TECHNICAL FIELD 
       [0001]    The present invention relates to a power transmitting device, more specifically, to a power transmitting device capable of miniaturizing and reducing the weight of a generator motor for a hybrid car provided with an engine and the generator motor, preventing the internal resistance and the inertia of the generator motor from becoming the driving resistance, and capable of effectively utilizing the energy. 
       BACKGROUND ART 
       [0002]    As a power transmitting device for a hybrid vehicle provided with an engine and a generator motor as a power source, the Non Patent Literature 1, for example, discloses one in which an input shaft to which the power from an engine is transmitted and a rotor of a generator motor are coaxially connected to each other, and a clutch capable of blocking the input from the engine and the generator motor is arranged between the generator motor and a change gear. In the power transmitting device disclosed in the Non Patent Literature 1, because the input shaft and the rotor of the generator motor are connected coaxially, the rotor always rotates accompanying the rotation of the input shaft of the engine. Thus, the rotor acts as a flywheel also, and can suppress the fluctuations in the rotation of the engine. 
       CITATION LIST 
     Non Patent Literature 
       [0000]    
       
         [Non Patent Literature 1] “Honda Technology”, [online], Honda Motor Co., Ltd., [Searched on Apr. 10, 2009], internet &lt;URL: http://www.honda.co.jp/tech/auto/engine/honda-ima/detail/index.html&gt; 
       
     
       SUMMARY OF INVENTION 
     Technical Problem 
       [0004]    However, according to the power transmitting device disclosed in the Non Patent Literature 1, the rotor always rotates not only in travel assisting and in regenerating by the generator motor but also in high speed traveling when the vehicle travels only by the driving force of the engine. As a result, the motor frame requires the strength sufficient to support the high speed rotation of the rotor in the rotatable range of the engine (the maximum rotational speed may possibly reach approximately 10,000 rpm), and therefore there was a problem that the generator motor became large and was increased in weight. 
         [0005]    Also, because the rotor of the generator motor always rotates, there was a problem that the internal resistance and the inertia of the generator motor became the driving resistance and the energy loss was caused in normal traveling when travel assisting by the generator motor was not required. 
         [0006]    The present invention has been developed to address the problems described above, and its object is to provide a power transmitting device capable of miniaturizing and reducing the weight of a generator motor for a hybrid vehicle provided with an engine and a generator motor, preventing the internal resistance and the inertia of the generator motor from becoming the driving resistance, and capable of effectively utilizing the energy. 
       Solution to Problem and Advantageous Effects of Invention 
       [0007]    In order to achieve the object, according to the power transmitting device described in claim  1 , by a first clutch, while the power is transmitted from an input shaft to a transmission shaft, transmission of the power from the transmission shaft to the input shaft is blocked and transmission of the power from the input shaft to the transmission shaft can be blocked. Also, by a second clutch, the power is transmitted from the transmission shaft to the input shaft and transmission of the power from the input shaft to the transmission shaft is blocked. Accordingly, by the first clutch and the second clutch, in travel assisting by the generator motor, the power of the generator motor inputted from the transmission shaft is transmitted to the input shaft, whereas in regenerating, the power can be transmitted from the input shaft to the generator motor through the transmission shaft. On the other hand, in high speed traveling when the vehicle travels only by the driving force of the engine, transmission of the power from the input shaft to the transmission shaft is blocked by the first clutch and the second clutch, and transmission of the power to a rotor can be prevented. As a result, because the frame of the generator motor does not require the strength sufficient to support high speed rotation of the rotor, there is an effect that the generator motor can be miniaturized and reduced in weight. 
         [0008]    Also, because rotation of the rotor in normal traveling when the travel assistance by the generator motor is not required can be prevented, the event that the internal resistance and the inertia of the generator motor become the driving resistance and the energy loss is caused can be prevented, and there is an effect that the energy can be utilized effectively. 
         [0009]    According to the power transmitting device described in claim  2 , by a third clutch, transmission of the power from the input shaft to the change gear is blocked, and, by the first clutch, power transmission from the input shaft to the transmission shaft is blocked, thereby the power is transmitted from the generator motor to the engine through the second clutch, and the generator motor is allowed to act as a starter of the engine. Because transmission of the power from the input shaft to the generator motor side has been blocked, after the engine starts, the power can be transmitted to the change gear only by connecting the third clutch. 
         [0010]    On the other hand, in the past, when the generator motor was used as a starter of the engine, in order that the vehicle did not move when the engine started, the generator motor was rotated to rotate the engine in a state the clutch between the generator motor and the change gear was blocked, and the engine was started. In order to start the vehicle, it was necessary to connect the clutch after the generator motor was controlled in order not to resist the engine. As a result, there were problems that it took long time from starting of the engine until starting of the vehicle and the control became complicated. 
         [0011]    However, according to the power transmitting device described in claim  2 , because the third clutch blocking transmission of the power from the input shaft to the change gear is provided, in addition to the effect of claim  1 , there are the effects that the power can be transmitted from the input shaft to the change gear only by connecting the third clutch which results that complicated control is not required, and the time from start of the engine to transmission of the power to the change gear can be shortened. 
         [0012]    Also, by blocking transmission of the power from the input shaft to the change gear by the third clutch in starting the engine, there is an effect that the vibration of the engine in starting can be made hardly be propagated to the vehicle body. Further, there are effects that, by blocking transmission of the power from the input shaft to the change gear by the third clutch, all the power from the engine is transmitted to the rotor in a state the vehicle is stopped, and the electric power can be generated using the generator motor. 
         [0013]    According to the power transmitting device described in claim  3 , in a fourth clutch, an energizing force is applied to sprags by an energizing member, the sprags tilt toward the self-lock direction, thereby a friction force occurs at contact points of the engaging surfaces with the outer peripheral surface and the inner peripheral surface, and the sprags engage with an inner ring and an outer ring due to a self-lock angle. As a result, relative rotation with respect to the inner ring and the outer ring toward a specific rotational direction is restricted. On the other hand, a load is applied to the sprags by a load application device resisting the energizing force of the energizing member, the sprags tilt toward the counter-self-lock direction, thereby engagement of the sprags with the inner ring and the outer ring is released, and the inner ring and the outer ring rotate relatively with each other. Because transmitting and blocking of the rotation toward a specific direction are switched by tilting the sprags thus, in addition to the effects of claim  1  or claim  2 , there are effects that the time required for switching can be shortened and the speed can be changed quickly. 
         [0014]    Also, because the power is transmitted toward a specific direction and blocked by tilting the sprags, slipping of the inner ring and the outer ring with each other can be prevented in speed changing when the state transmission of the power is blocked changes to the state the power is transmitted. Therefore, there is an effect that generation of the impact in speed changing can be prevented. 
         [0015]    Further, by operating the load application device of the fourth clutch, transmission of the power from the connecting shaft to the output shaft is blocked, and, after the engine starts, the power can be transmitted from the connecting shaft to the output shaft by stopping operation of the load application device. Thus, because the power can be transmitted to the output shaft only by stopping operation of the load application device, there are effects that complicated control is not required and the time from the start of the engine until transmission of the power to the output shaft can be shortened. 
         [0016]    According to the power transmitting device described in claim  4 , because a fifth clutch blocking transmission of the power from the engine to a switching device is provided, in addition to any effect of claims  1  to  3 , there are effects that, by separating the engine from the switching device in regenerating, the engine can be prevented from becoming the driving resistance of the generator motor, the energy loss can be eliminated, and the regeneration amount can be increased. Also, by separating the engine from the switching device, the vehicle can travel by the driving force of the generator motor only, and therefore there is an effect that the fuel consumption amount of the engine can be suppressed. 
         [0017]    According to the power transmitting device described in claim  5 , because the change gear is connected to the switching device not through the clutch, the sprags can be tilted toward the self-lock direction by the energizing force of the energizing member only by the control of stopping operation of the load application device of the fourth clutch after the engine is started by the generator motor in a state the load application device of the fourth clutch is operated. Thus, the power from the engine is transmitted to the output shaft, and the vehicle can be started. Therefore, in addition to the effects of claim  3  or claim  4 , there are the effects that from the start of the engine to the start of the vehicle can be controlled easily, and the time required therefor can be shortened. 
         [0018]    According to the power transmitting device described in claim  6 , because a step-up gear for increasing the rotational speed of the rotor by rotation of the input shaft is provided, in addition to any effect of claims  1  to  5 , there are the effects that the rotational speed of the rotor is increased while the electric power is generated and the electric power generation amount can be increased. Also, there is an effect that the torque of the input shaft can be increased in starting the engine and in travel assisting by the generator motor. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0019]      FIG. 1  is a schematic view schematically showing a vehicle mounting a power transmitting device in a first embodiment of the present invention. 
           [0020]      FIG. 2  is a schematic view schematically showing a power transmitting device in the first embodiment. 
           [0021]      FIG. 3  is a cross-sectional view of the first clutch. 
           [0022]      FIG. 4  is a cross-sectional view of the first clutch taken along the line IV-IV in  FIG. 3 . 
           [0023]      FIG. 5  is a partial enlarged cross-sectional view of the first clutch showing a part shown in V of  FIG. 4  in an enlarged state. 
           [0024]      FIG. 6  is a schematic view schematically showing the internal structure of the second clutch. 
           [0025]      FIG. 7  is a schematic view schematically showing the internal structure of the power transmitting device in starting the engine. 
           [0026]      FIG. 8  is a schematic view schematically showing the internal structure of the power transmitting device in travel assisting by the generator motor. 
           [0027]      FIG. 9  is a schematic view schematically showing the internal structure of the power transmitting device in high speed traveling when the vehicle travels only by the driving force of the engine. 
           [0028]      FIG. 10  is a schematic view schematically showing the internal structure of the power transmitting device in shifting up. 
           [0029]      FIG. 11  is a schematic view schematically showing the internal structure of the power transmitting device in regenerating. 
           [0030]      FIG. 12  is a schematic view schematically showing the internal structure of the vehicle mounting the power transmitting device in a second embodiment of the present invention. 
           [0031]      FIG. 13  is a schematic view schematically showing a power transmitting device in the second embodiment. 
           [0032]      FIG. 14  is a schematic view schematically showing the internal structure of the power transmitting device in starting the engine. 
           [0033]      FIG. 15  is a schematic view schematically showing the internal structure of the power transmitting device in travel assisting by the generator motor. 
           [0034]      FIG. 16  is a schematic view schematically showing the internal structure of the power transmitting device in high speed traveling when the vehicle travels by only the driving force of the engine. 
           [0035]      FIG. 17  is a schematic view schematically showing the internal structure of the power transmitting device in regenerating. 
           [0036]      FIG. 18  is a schematic view schematically showing a power transmitting device in a third embodiment. 
       
    
    
     DESCRIPTION OF EMBODIMENTS 
       [0037]    Below, embodiments of the present invention will be described referring to attached drawings.  FIG. 1  is a schematic view schematically showing a vehicle  100  mounting a power transmitting device  1  in a first embodiment of the present invention. Arrows F-B, L-R in  FIG. 1  respectively show the front-back direction and the left-right direction of the vehicle  100 . 
         [0038]    First, the constitution outline of the vehicle  100  will be described. As shown in  FIG. 1 , the vehicle  100  includes a front unit  110  driving front wheels  101  (a left front wheel  101 FL and a right front wheel  101 FR). The front unit  110  mainly includes an engine  111  and a generator motor  112  as power sources, and a power transmitting device  113  transmitting the power of the engine  111  and the generator motor  112  to the front wheels  101 , and is constituted so as to drive the front wheels  101  selecting the power of the two sources of the engine  111  and the generator motor  112 . Also, the front unit  110  is constituted so as to regenerate the power generated by the generator motor  112  as the generator motor  112  also has the function as a power generator. 
         [0039]    Next, the detailed constitution of the power transmitting device  1  will be described referring to  FIG. 2 .  FIG. 2  is a schematic view schematically showing the internal structure of the power transmitting device  1 . In  FIG. 2 , for the purpose of facilitating understanding, only the constitutions assuming the function of transmitting the power are shown. As shown in  FIG. 2 , the power transmitting device  1  is constituted so as to mainly include an input shaft  2  transmitting the power from the engine  111  to a change gear  5 , a transmission shaft  3  transmitting the power transmitted from the input shaft  2  to the generator motor  112 , and a switching device  4  disposed on a power transmission route from the input shaft  2  to the transmission shaft  3  and switching the power transmitting direction between the input shaft  2  and the transmission shaft  3 . In the present embodiment, the switching device  4  is disposed on the input shaft  2 . 
         [0040]    Further, the power transmitting device  1  is constituted so as to include a transmission gear pair  2   a  to which the power is transmitted from the input shaft  2 , and the change gear  5  to which the power is transmitted from the transmission gear pair  2   a . The change gear  5  is connected to the switching device  4  not through a clutch. The change gear  5  is constituted so as to mainly include a connecting shaft  5   a  connected to the input shaft  2  through the transmission gear pair  2   a  and inputted with the power from the engine  111 , an output shaft  5   b  disposed in parallel with the connecting shaft  5   a , plural first gear pairs  6 ,  7  disposed on the output shaft  5   b  and the connecting shaft  5   a  and set so as to mesh with each other and to make different gear ratios, and a second gear pair  8  disposed on the output shaft  5   b  and the input shaft  5   a  and engaging with each other. Also, the power transmitted to the output shaft  5   b  is constituted so as to be outputted to outside the power transmitting device  1  and transmitted to the front wheels  101 . 
         [0041]    The power transmitting device  1  transmits the power between the generator motor  112  including a stator  112   s  and a rotor  112   r  and the input shaft  2  through a step-up gear  80 . In the present embodiment, the step-up gear  80  is constituted so as to include a planetary gear device. The planetary gear device (the step-up gear  80 ) includes a sun gear  80   s  rotating with inputted rotation from the transmission shaft  3  connected to the rotor  112   r  being transmitted, plural planetary gears  80   p  meshed with the outer periphery of the sun gear  80   s , a ring gear  80   r  meshed with the plural planetary gears  80   p , and a carrier  80   c  supporting the plural planetary gears  80   p , rotated around the rotation center of the sun gear  80   s , and transmitting the inputted rotation from the transmission shaft  3  to the switching device  4 . The ring gear  80   r  is fixed to a case la composing an enclosure of the power transmitting device  1  so as not to be rotatable. 
         [0042]    Here, when the teeth number of the sun gear  80   s  is a, the teeth number of the planetary gear  80   p  is b, and the teeth number of the ring gear  80   r  is c, the reduction ratio (rotational speed of the sun gear  80   s /rotational speed of the carrier  80   c ) of the step-up gear  80  becomes l+c/a regardless of the teeth number b of the planetary gear  80   p , and the rotational speed of the sun gear  80   s  becomes (1+c/a) times of the rotational speed of the carrier  80   c . Thus, when the power is transmitted from the input shaft  2  to the transmission shaft  3 , the rotational speed of the transmission shaft  3  is increased to increase the rotational speed of the rotor  112   r , and the electric power generation amount by the generator motor  112  can be increased. On the other hand, in starting the engine  111  and in travel assisting by the generator motor  112  when the power of the generator motor  112  is transmitted from the transmission shaft  3  to the input shaft  2 , the torque of the input shaft  2  is increased, and the starting performance and the acceleration performance can be improved. 
         [0043]    The switching device  4  is constituted so as to include a first clutch  10  and a second clutch  20 . The first clutch  10  is for transmitting and blocking the power between the input shaft  2  and the transmission shaft  3 , and is constituted so as to block transmission of the power from the transmission shaft  3  to the input shaft  2  and to be capable of blocking transmission of the power from the input shaft  2  to the transmission shaft  3  while transmitting the power inputted from the input shaft  2  to the transmission shaft  3 . 
         [0044]    Here, the detailed constitution of the first clutch  10  will be described referring to  FIG. 3  and  FIG. 4 .  FIG. 3  is a cross-sectional view of the first clutch  10 , and  FIG. 4  is a cross-sectional view of the first clutch  10  taken along the line IV-IV in  FIG. 3 . As shown in  FIG. 3  and  FIG. 4 , the first clutch  10  is constituted so as to mainly include a first inner ring  11 , a first outer ring  12  surrounding the outer periphery of the first inner ring  11 , plural first sprags  13  disposed between the first inner ring  11  and the first outer ring  12 , a retainer  14  retaining the first sprags  13 , and a load application device  15 . 
         [0045]    The first inner ring  11  is a member assuming the function of transmitting the power, includes an outer peripheral surface  11   a  with a circular cross-sectional shape and is constituted so as to be rotatable around an axis O as shown in  FIG. 3  and  FIG. 4 . Also, the first inner ring  11  is connected to the carrier  80   c  (refer to  FIG. 2 ). The first outer ring  12  is a member assuming the function of transmitting the power with the first inner ring  11 , includes an inner peripheral surface  12   a  with a circular cross-sectional shape opposing the outer peripheral surface lie of the first inner ring  11  and is constituted so as to be rotatable around the axis O similarly to the first inner ring  11  as shown in  FIG. 3  and  FIG. 4 . Also, the first outer ring  12  is connected to the input shaft  2  (refer to  FIG. 2 ). 
         [0046]    The first sprags  13  are members assuming the function of engaging the first inner ring  11  and the first outer ring  12  with each other, include engaging surfaces  13   a ,  13   b  (refer to  FIG. 5 ) contacting the outer peripheral surface  11   a  and the inner peripheral surface  12   a  respectively, and are disposed by plural numbers at equal intervals in the peripheral direction between the opposing outer peripheral surface  11   a  and the inner peripheral surface  12   a  as shown in  FIG. 4 . Also, the first sprags  13  are energized toward the peripheral direction of the outer peripheral surface  11   a  and the inner peripheral surface  12   a  by a ribbon spring  16  (refer to  FIG. 5 ). Here, the ribbon spring  16  will be described referring to  FIG. 5 .  FIG. 5  is a partial enlarged cross-sectional view of the first clutch  10  showing a part shown in V of  FIG. 4  in an enlarged state. 
         [0047]    The ribbon spring  16  is a member generating an angular moment of the arrow S direction (hereinafter referred to as “the self-lock direction”) of  FIG. 5  in the first sprags  13  so as to apply an energizing force to the first sprags  13  and to make the engaging surfaces  13   a ,  13   b  contact the outer peripheral surface  11   a  and the inner peripheral surface  12   a , is formed by subjecting a metallic material with bending work in a wave shape as shown in  FIG. 5 , and is constituted so as to apply an energizing force to the first sprags  13  utilizing its elasticity. However, the ribbon spring  16  may be formed of a coil spring. By applying the energizing force to the first sprags  13  by the ribbon spring  16 , the first sprags  13  tilt toward the self-lock direction so that the engaging surfaces  13   a ,  13   b  contact the outer peripheral surface  11   a  and the inner peripheral surface  12   a . As a result, as shown in  FIG. 5 , friction forces are generated at contact points A of the inner peripheral surface  12   a  and the engaging surfaces  13   b  and contact points B of the outer peripheral surface  11   a  and the engaging surfaces  13   a , and, when the first inner ring  11  and the first outer ring  12  rotate toward a predetermined direction by positional shifting of the respective contact points A, B in the peripheral direction of the outer peripheral surface  11   a  and the inner peripheral surface  12   a , the first sprags  13  engage with the first inner ring  11  and the first outer ring  12 . 
         [0048]    That is, when the first outer ring  12  rotates relative to the first sprags  13  toward the arrow Ro direction (hereinafter referred to as “the lock direction”) of  FIG. 5  when viewed from the first inner ring  11  side in relative rotation with respect to the first inner ring  11 , the first sprags  13  engage with the first inner ring  11  and the first outer ring  12 . Thus, the input shaft  2  (refer to  FIG. 2 ) rotates with the first outer ring  12 . On the other hand, when the first outer ring  12  rotates relative to the first sprags  13  toward the counter-arrow Ro direction (hereinafter referred to as “the free direction”) of  FIG. 5  when viewed from the first inner ring  11  side in relative rotation with respect to the first inner ring  11 , the first sprags tilt toward the counter-self-lock direction resisting the energizing force of the ribbon spring  16  by the friction force applied to the contact points A, and engagement of the first sprags  13  with the first inner ring  11  and the first outer ring  12  is released. As a result, the first outer ring  12  makes the first inner ring  11  idly rotate. 
         [0049]    Also, when the first inner ring  11  rotates relative to the first sprags  13  toward the arrow Ri direction (the lock direction) of  FIG. 5  when viewed from the first outer ring  12  side in relative rotation with respect to the first outer ring  12 , the first sprags  13  engage with the first inner ring  11  and the first outer ring  12 . As a result, the first outer ring  12  rotates with the first inner ring  11  (refer to  FIG. 2 ). On the other hand, when the first inner ring  11  rotates relative to the first sprags  13  toward the counter-arrow Ri direction (the free direction) of  FIG. 5  when viewed from the first outer ring  12  side in relative rotation with respect to the first outer ring  12 , the first sprags tilt toward the counter-self-lock direction resisting the energizing force of the ribbon spring  16  by the friction force applied to the contact points B, and the first outer ring  12  makes the first inner ring  11  (refer to  FIG. 2 ) idly rotate. 
         [0050]    Description will be made coming back to  FIG. 3  and  FIG. 4 . The retainer  14  is a member retaining the first sprags  13  so as to tilt toward the peripheral direction of the outer peripheral surface  11   a  and the inner peripheral surface  12   a , and is constituted so as to include a retaining part  14   a  and a load transmitting part  14   b  as shown in  FIG. 3  and  FIG. 4 . The retaining part  14   a  is a portion retaining the first sprags  13 , is extended toward the axis O direction and retains the upper end side of the first sprags  13  as shown in  FIG. 3  and  FIG. 4 . 
         [0051]    The load transmitting part  14   b  is a portion to which a load from the load application device  15  is transmitted, and is extended toward the direction crossing the axis O direction as shown in  FIG. 3 . Thus, when compared with the case the load transmitting part  14   b  is extended toward the axis O direction, the dimension of the retainer  14  in the axis O direction can be shortened, and the first clutch  10  can be miniaturized. Also, as shown in  FIG. 4 , the load transmitting part  14   b  is formed in a gear shape and is constituted so that the load is transmitted from the load application device  15  through a gear mechanism constituted with a pinion  15   b  described below. Thus, the energy loss caused through a load transmission route from the load application device  15  to the retainer  14  can be reduced, and the load can be transmitted to the retainer  14  efficiently. 
         [0052]    The load application device  15  is a device for applying a load to the first sprags  13  resisting the energizing force of the ribbon spring  16  and tilting the first sprags  13  toward the counter-self-lock direction (opposite to the arrow S rotational direction of  FIG. 5 ), and is constituted so as to include an actuator  15   a  and the pinion  15   b  as shown in  FIG. 3  and  FIG. 4 . 
         [0053]    The actuator  15   a  is a power source generating a load applied to the first sprags  13 , is constituted of a motor (an AC motor or a DC motor), and is constituted so as to be driven by the electric power supplied from an electric power source (not shown). Thus, because the actuator  15   a  is constituted of the motor, when compared with the case the actuator  15   a  is constituted of a cylinder, a solenoid, and the like for example, the structure of the load application device  15  can be simplified and miniaturized. Also, when the structure of the load application device  15  is complicated, the load application device  15  becomes large and the first clutch  10  becomes large, however, when the structure of the load application device  15  can be simplified and miniaturized, the first clutch  10  can be miniaturized. 
         [0054]    The pinion  15   b  is a member for transmitting the power of the actuator  15   a  to the retainer  14 , is formed into a gear shape engaging with the load transmitting part  14   b  of the retainer  14 , and constitutes the gear mechanism with the load transmitting part  14   b  as shown in  FIG. 3 . By transmission of the power of the actuator  15   a  to the retainer  14  by the pinion  15   b , the load is applied to the first sprags  13  through the retainer  14 . Thus, because the load application device  15  applies the load to the first sprags  13  through the retainer  14 , the load can be applied to plural the first sprags  13  at one time, and the load can be applied to the first sprags  13  efficiently. 
         [0055]    According to the load application device  15  constituted as described above, by applying the load to the first sprags  13  resisting the energizing force of the ribbon spring  16 , the first sprags  13  are tilted toward the counter-self-lock direction, and engagement of the first sprags  13  with the first inner ring  11  and the first outer ring  12  can be released forcibly. Thus, even when the power transmitted from the generator motor  112  is inputted to the first inner ring  11  of the first clutch  10  and the first inner ring  11  rotates to the lock direction (the arrow Ri direction of  FIG. 5 ) relative to the first sprags  13 , engagement of the first sprags  13  with the first inner ring  11  and the first outer ring  12  is released forcibly by the load application device  15 , thereby the first outer ring  12  is rotated idly, and transmission of the power between the input shaft  2  and the transmission shaft  3  can be blocked. Also, even when the power transmitted from the engine  111  is inputted to the first outer ring  12  of the first clutch  10  and the first outer ring  12  rotates toward the lock direction (the arrow Ro direction of  FIG. 5 ) relative to the first sprags  13 , engagement of the first sprags  13  with the first inner ring  11  and the first outer ring  12  is released forcibly by the load application device  15 , thereby the first inner ring  11  is rotated idly, and transmission of the power between the input shaft  2  and the transmission shaft  3  can be blocked. 
         [0056]    Next, the second clutch  20  of the switching device  4  will be described referring to  FIG. 6 .  FIG. 6  is a schematic view schematically showing the internal structure of the second clutch  20 . The second clutch  20  is for transmitting the power inputted from the transmission shaft  3  to the input shaft  2  while blocking transmission of the power from the input shaft  2  to the transmission shaft  3 . Because the second clutch  20  is constituted similarly to the first clutch  10  with the exception that the load application device  15  is omitted, detailed description will be omitted. A second inner ring  21  (refer to  FIG. 2 ) of the second clutch  20  is connected to the carrier  80   c , and a second outer ring  22  (refer to  FIG. 2 ) is connected to the input shaft  2 . 
         [0057]    According to the second clutch  20 , when the power of the engine  111  is inputted from the second outer ring  22  and the second outer ring  22  rotates relative to the second sprags  23  toward the arrow Ro direction (the lock direction) of  FIG. 6  when viewed from the second inner ring  21  side in relative rotation with respect to the second inner ring  21 , second sprags  23  engage with an outer peripheral surface  21   a  of the second inner ring  21  and an inner peripheral surface  22   a  of the second outer ring  22 . As a result, the second outer ring  22  rotates with the second inner ring  21 , and the power is transmitted from the second outer ring  22  to the second inner ring  21 . On the other hand, when the second outer ring  22  rotates relative to the second sprags  23  toward the counter-arrow Ro direction (the free direction) of  FIG. 6  when viewed from the second inner ring  21  side in relative rotation with respect to the second inner ring  21 , engagement of the second sprags  23  with the second inner ring  21  and the second outer ring  22  is released, and the second outer ring  22  makes the second inner ring  21  idly rotate. 
         [0058]    Also, when the power from the generator motor  112  is transmitted to the second clutch  20  and the second inner ring  21  rotates relative to the second sprags  23  toward the counter-arrow Ri direction (the free direction) of  FIG. 6  when viewed from the second outer ring  22  side in relative rotation with respect to the second outer ring  22 , engagement of the second sprags  23  with the second inner ring  21  and the second outer ring  22  is released. As a result, the second outer ring  22  makes the input shaft  2  idly rotate, and transmission of the power between the input shaft  2  and the transmission shaft  3  is blocked. On the other hand, when the second inner ring  21  rotates relative to the second sprags  23  toward the arrow Ri direction (the lock direction) of  FIG. 6  when viewed from the second outer ring  22  side in relative rotation with respect to the second outer ring  22 , the second sprags  23  engage with the second inner ring  21  and the second outer ring  22 . As a result, the second outer ring  22  rotates with the second inner ring  21 , and the power is transmitted between the input shaft  2  and the transmission shaft  13 . 
         [0059]    Description will be made coming back to  FIG. 2 . In the input shaft  2  from the engine  111  to the switching device  4 , a fifth clutch  50  is disposed. With the fifth clutch  50 , transmission of the power from the engine  111  to the switching device  4  and the change gear  5  can be blocked. The first gear pairs  6 ,  7  of the change gear  5  include driving gears  6   a ,  7   a  disposed on the connecting shaft  5   a  and driven by the power transmitted from the input shaft  2  to the connecting shaft  5   a , and driven gears  6   b ,  7   b  disposed on the output shaft  5   b  and followingly driven by the driving gears  6   a ,  7   a . Here, with respect to the first gear pairs  6 ,  7 , the first speed and the second speed are disposed so as to be closer to the transmission gear pair  2   a  in the order of decreasing gear ratio (teeth number of driven gear/teeth number of driving gear), and, in the present embodiment, the first gear pair  6  is the first speed and the first gear pair  7  is the second speed. Also, the reverse travel stage is omitted in the illustration. With respect to the reverse travel stage, a pinion gear can be inserted between the first gear pair. 
         [0060]    The driving gears  6   a ,  7   a  constituting the first gear pairs  6 ,  7  are formed integrally with the connecting shaft  5   a  respectively. On the other hand, the driven gears  6   b ,  7   b  respectively opposing to and engaging with the driving gears  6   a ,  7   a  are fixed to the output shaft  5   b  through a fourth clutch  40  described below. The fourth clutch  40  is for blocking transmission of the power from the output shaft  5   b  to the connecting shaft  5   a  while transmitting the power from the connecting shaft  5   a  to the output shaft  5   b , and is constituted so as to be capable of blocking transmission of the power from the connecting shaft  5   a  to the output shaft  5   b . Because the fourth clutch  40  is constituted similarly to the first clutch  10 , detailed description will be omitted. Also, with respect to a portion same with the corresponding portion of the first clutch, a same reference numeral is used and description will be hereinafter omitted. 
         [0061]    A fourth inner ring  41  of the fourth clutch  40  is formed integrally with the output shaft  5   b , and a fourth outer ring  42  is formed integrally with the driven gears  6   b ,  7   b . According to the fourth clutch  40 , when the power of the engine  111  and the generator motor  112  is inputted from the driven gears  6   b ,  7   b  through the input shaft  2 , the connecting shaft  5   a  and the driving gears  6   a ,  7   a  and the fourth outer ring  42  connected to the driven gears  6   b ,  7   b  rotates relative to fourth sprags  43  toward the lock direction (the arrow Ro direction of  FIG. 5 ) when viewed from the fourth inner ring  41  side in relative rotation with respect to the fourth inner ring  41 , the fourth sprags  43  engage with the fourth inner ring  41  and the fourth outer ring  42 . As a result, the output shaft  5   b  rotates with the driven gears  6   b ,  7   b  and the power is transmitted. On the other hand, when the fourth outer ring  42  rotates relative to the fourth sprags  43  toward the free direction (the counter-arrow Ro direction of  FIG. 5 ) when viewed from the fourth inner ring  41  side in relative rotation with respect to the fourth inner ring  41 , engagement of the fourth sprags  43  with the fourth inner ring  41  and the fourth outer ring  42  is released, and the driven gears  6   b ,  7   b  make the output shaft  5   b  idly rotate. 
         [0062]    Also, when the power is transmitted from the output shaft  5   b  to the fourth inner ring  41  of the fourth clutch  40 , the fourth inner ring  41  rotates relative to the fourth sprags  43  to the free direction (the counter-arrow Ri direction of  FIG. 5 ) when viewed from the fourth outer ring  42  side in relative rotation with respect to the fourth outer ring  42 , engagement of the fourth sprags  43  with the fourth inner ring  41  and the fourth outer ring  42  is released. As a result, the driven gears  6   b ,  7   b  make the output shaft  5   b  idly rotate, and transmission of the power from the output shaft  5   b  to the connecting shaft  5   a  is blocked. On the other hand, when the fourth inner ring  41  rotates relative to the fourth sprags  43  toward the lock direction (the arrow Ri direction of  FIG. 5 ) when viewed from the fourth outer ring  42  side in relative rotation with respect to the fourth outer ring  42 , the fourth sprags  23  engage with the fourth inner ring  41  and the fourth outer ring  42 . As a result, the driven gears  6   b ,  7   b  rotate with the output shaft  5   b , and the power is transmitted. 
         [0063]    Because the fourth clutch  40  includes the load application device  15  (refer to  FIG. 4 ) similarly to the first clutch  10 , even when the power is transmitted to the fourth inner ring  41  and the fourth outer ring  42  and the fourth inner ring  41  and the fourth outer ring  42  rotate relative to the fourth sprags  43  toward the lock direction (the arrow Ri direction or the arrow Ro direction of  FIG. 5 ), engagement of the fourth sprags  43  with the fourth inner ring  41  and the fourth outer ring  42  can be forcibly released by the load application device  15 . Thus the fourth outer ring  42  is rotated idly, and transmission of the power can be blocked. 
         [0064]    A driving gear  8   a  constituting the second gear pair  8  is formed integrally with the connecting shaft  5   a  through a sixth clutch  60  described below. On the other hand, a driven gear  8   b  opposing to and engaging with the driving gear  8   a  is fixed to the output shaft  5   b . The sixth clutch  60  is for blocking transmission of the power from the connecting shaft  5   a  to the output shaft  5   b  while transmitting the power from the output shaft  5   b  to the connecting shaft  5   a , and is constituted so as to be capable of blocking transmission of the power from the output shaft  5   b  to the connecting shaft  5   a . Because the sixth clutch  60  is constituted similarly to the first clutch  10  (refer to  FIG. 5 ) with the exception that the load application device  15  is omitted, detailed description will be omitted. Also, with respect to a portion same with the corresponding portion of the first clutch  10 , a same reference numeral is used and description will be hereinafter omitted. 
         [0065]    A sixth inner ring  61  of the sixth clutch  60  is formed integrally with the connecting shaft  5   a , and a sixth outer ring  62  is formed integrally with the driving gear  8   a . According to the sixth clutch  60 , when the power of the engine  111  and the generator motor  112  is transmitted to the input shaft  2  and the connecting shaft  5   a  and the sixth inner ring  61  of the sixth clutch  60  rotates relative to sixth sprags  63  to the free direction (the counter-arrow Ri direction of  FIG. 5 ) when viewed from the sixth outer ring  62  side in relative rotation with respect to the sixth outer ring  62 , engagement of the sixth sprags  63  with the sixth inner ring  61  and the sixth outer ring  62  is released, the connecting shaft  5   a  makes the driving gear  8   a  idly rotate, and transmission of the power from the connecting shaft  5   a  to the output shaft  5   b  is blocked. On the other hand, when the sixth inner ring  61  rotates relative to the sixth sprags  63  toward the lock direction (the arrow Ri direction of  FIG. 5 ) when viewed from the sixth outer ring  62  side in relative rotation with respect to the sixth outer ring  62 , the sixth sprags  63  engage with the sixth inner ring  61  and the sixth outer ring  62 . As a result, the connecting shaft  5   a  rotates with the driving gear  8   a , and the power is transmitted. 
         [0066]    Also, when the power is transmitted to the sixth clutch  60  from the output shaft  5   b  through the driven gear  8   b  and the driving gear  8   a , the sixth outer ring  62  rotates relative to the sixth sprags  63  to the lock direction (the arrow Ro direction of  FIG. 5 ) when viewed from the sixth inner ring  61  side in relative rotation with respect to the sixth inner ring  61 , and the sixth sprags  63  engage with the sixth inner ring  61  and the sixth outer ring  62 . As a result, the driving gear  8   a  rotates with the connecting shaft  5   a , and the power is transmitted. On the other hand, when the sixth outer ring  62  rotates relative to the sixth sprags  63  toward the free direction (the counter-arrow Ro direction of  FIG. 5 ) when viewed from the sixth inner ring  61  side in relative rotation with respect to the sixth inner ring  61 , engagement of the sixth sprags  63  with the sixth inner ring  61  and the sixth outer ring  62  is released. As a result, the driving gear  8   a  makes the connection shaft  5   a  idly rotate, and transmission of the power from the output shaft  5   b  to the connecting shaft  5   a  is blocked. 
         [0067]    Next, the working condition of the power transmitting device  1  in the first embodiment constituted as described above will be described referring to  FIG. 7  through to  FIG. 11 .  FIG. 7  through to  FIG. 11  schematically show the front views of the internal structure of the power transmitting device  1 . In  FIG. 6  through to  FIG. 11 , in order to facilitate understanding, the transmission route of the power is shown in the arrow P, and respective rotational directions of the driving gears  6   a ,  7   a ,  8   a , the driven gears  6   b ,  7   b ,  8   b , the fourth outer ring  42  of the fourth clutch  40  and the sixth outer ring  62  of the sixth clutch  60  are shown in the arrows. Also, the case in which the load application devices  15  of the first clutch  10  and the fourth clutch  40  are operated and engagement of the first sprags  13  and the fourth sprags  43  with the first inner ring  11  and the first outer ring  12 , as well as the fourth inner ring  41  and the fourth outer ring  42  is released is described as “ON”, whereas the case in which the load application devices  15  of the first clutch  10  and the fourth clutch  40  are not operated and the first sprags  13  and the fourth sprags  43  can engage is described as “OFF”. 
         [0068]    Also, as described above, in the present embodiment, the first gear pairs  6 ,  7  are disposed so as to be closer to the transmission gear pair  2   a  in the order of decreasing gear ratio (teeth number of driven gear/teeth number of driving gear). When the gear ratios of the first gear pairs  6 ,  7  and the second gear pair  8  are k 1 , k 2 , k 3  in this order, the gear ratios have the relation of k 1 &gt;k 2 &gt;k 3 . Further, the driven gear  8   b  of the second gear pair  8  is formed so that the teeth number thereof becomes smaller than the minimum teeth number between the teeth number of the driven gears  6   b ,  7   b  of the first gear pairs  6 ,  7  (the teeth number of the driven gear  7   b  in the present embodiment). Thus, when the power is transmitted from the connecting shaft  5   a  to the output shaft  5   b  and the rotational speeds of the driven gears  6   b ,  7   b ,  8   b  are α 1 , α 2 , α 3  respectively, respective rotational speeds are unequivocally decided by the rotational speed of the connecting shaft  5   a , and have the relation of α 1 &lt;α 2 &lt;α 3  from the relation of the gear ratio. Also, the rotational speed of the output shaft  5   b  becomes the rotational speed according to the shift stage. 
         [0069]    First, the power transmitting device  1  in starting the engine  111  will be described referring to  FIG. 7 .  FIG. 7  is a schematic view schematically showing the internal structure of the power transmitting device  1  in starting the engine  111 . In starting the engine  111 , the fifth clutch  50  is connected, and the load application device  15  (refer to  FIG. 4 ) of the first clutch  10  and the load application device  15  (refer to  FIG. 4 ) of the fourth clutch  40  are operated (ON). Under this condition, when the generator motor  112  is activated and the rotor  112   r  is rotated, the power is transmitted to the transmission shaft  3  and the sun gear  80   s  rotates. Accompanying it, the carrier  80   c  rotates, the first inner ring  11  of the first clutch  10  rotates toward the free direction (the counter-arrow Ri direction of  FIG. 5 ) when viewed from the first outer ring  12  side in relative rotation with respect to the first outer ring  12 , and the second inner ring  21  of the second clutch  20  rotates toward the lock direction (the arrow Ri direction of  FIG. 6 ) when viewed from the second outer ring  22  side in relative rotation with respect to the second outer ring  22 . Thus, the second sprags  23  engage with the second inner ring  21  and the second outer ring  22  of the second clutch  20 , and the power of the carrier  80   c  is transmitted to the input shaft  2 . As a result, the engine  111  is rotated through the fifth clutch  50 , and the engine  111  starts. 
         [0070]    When the engine  111  starts and the input shaft  2  is driven by the engine  111 , the second outer ring  22  of the second clutch  20  rotates toward the free direction (the counter-arrow Ro direction of  FIG. 6 ) when viewed from the second inner ring  21  side in relative rotation with respect to the second inner ring  21 . Also, by rotation of the input shaft  2 , the first outer ring  12  of the first clutch  10  rotates toward the lock direction (the arrow Ro direction of  FIG. 5 ) when viewed from the first inner ring  11  side in relative rotation with respect to the first inner ring  11 , however, because the load application device  15  of the first clutch  10  has been operated, the first inner ring  11  idly rotates inside the first outer ring  12 . Accordingly, after the engine  111  starts, the power from the input shaft  2  to the transmission shaft  3  is blocked. When the rotational speed of the engine  111  is increased also, transmission of the power from the input shaft  2  to the transmission shaft  3  is similarly blocked. Accordingly, the generator motor frame does not require the strength sufficient to support high speed rotation of the rotor  112   r , and therefore the generator motor  112  can be miniaturized and reduced in weight. 
         [0071]    Also, when the power from the input shaft  2  is transmitted to the connecting shaft  5   a  through the transmission gear pair  2   a , the driven gears  6   b ,  7   b  of the first gear pairs  6 ,  7  rotate to rotate the fourth outer ring  42  (refer to  FIG. 2 ) of the fourth clutch  40 , and the sixth inner ring  61  (refer to  FIG. 2 ) of the sixth clutch  60  rotates. Although the fourth outer ring  42  of the fourth clutch  40  rotates toward the lock direction (the arrow Ro direction of  FIG. 5 ) when viewed from the fourth inner ring  41  side in relative rotation with respect to the fourth inner ring  41 , because the load application device  15  (refer to  FIG. 4 ) of the fourth clutch  40  has been operated, the fourth outer ring  42  makes the fourth inner ring  41  idly rotate. Accordingly, the power is not transmitted to the output shaft  5   b . Further, because the sixth inner ring  61  (refer to  FIG. 2 ) of the sixth clutch  60  rotates toward the free direction (the counter-arrow Ri direction of  FIG. 5 ) when viewed from the sixth outer ring  62  side in relative rotation with respect to the sixth outer ring  62 , the sixth inner ring  61  makes the sixth outer ring  62  idly rotate. Accordingly, the power is not transmitted to the output shaft  5   b . Therefore, transmission of the power to the front wheels  101  in starting the engine  111  can be prevented, and, even when a cell motor (starter) has not been mounted, the power can be transmitted from the input shaft  2  to the engine  111  using the generator motor  112 , and the engine  111  can be started. Also, by stopping operation of the load application device  15  (refer to  FIG. 4 ) of the fourth clutch  40  of the first gear pair  6 , the fourth sprags  43  engage with the fourth inner ring  41  and the fourth outer ring  42 , and the power is transmitted to the output shaft  5   b . Accordingly, by simple control of only stopping operation of the load application device  15  of the fourth clutch  40 , the time after the start of the engine  111  until transmission of the power to the output shaft  5   b  can be shortened. 
         [0072]    Next, the power transmitting device  1  in travel assisting when the driving force of the engine  111  is assisted by the driving force of the generator motor  112  will be described referring to  FIG. 8 .  FIG. 8  is a schematic view schematically showing the internal structure of the power transmitting device  1  in travel assisting by the generator motor  112 . In travel assisting by the generator motor  112 , the fifth clutch  50  maintains the connecting state, and operation of the load application device  15  (refer to  FIG. 4 ) of the first clutch  10  is maintained (ON). Also, the load application device  15  of the fourth clutch of the first gear pair  6  is made a non-operated state (OFF), and the load application device  15  of the fourth clutch of the first gear pair  7  is operated (ON). Under the condition, when the power from the engine  111  is transmitted to the input shaft  2 , the first outer ring  12  (refer to  FIG. 2 ) of the first clutch  10  rotates toward the lock direction (the arrow Ro direction of  FIG. 5 ) when viewed from the first inner ring  11  side in relative rotation with respect to the first inner ring  11 . However, because the load application device  15  of the first clutch  10  has been operated, the first outer ring  12  of the first clutch  10  makes the first inner ring  11  of the first clutch  10  idly rotate. Also, in the second clutch  20 , because the second outer ring  22  rotates toward the free direction (the counter-arrow Ro direction of  FIG. 6 ) when viewed from the second inner ring  21  side in relative rotation with respect to the second inner ring  21 , the second outer ring  22  makes the second inner ring  21  idly rotate. Accordingly, transmission of the power from the input shaft  2  to the generator motor  112  is blocked. 
         [0073]    On the other hand, when the generator motor  112  is driven and the power from the rotor  112   r  is transmitted to the switching device  4 , the second inner ring  21  (refer to  FIG. 2 ) of the second clutch  20  rotates toward the lock direction (the arrow Ri direction of  FIG. 5 ) when viewed from the second outer ring  22  side in relative rotation with respect to the second outer ring  22 . Accordingly, the power of the engine  111  and the generator motor  112  is transmitted to the input shaft  2 . 
         [0074]    When the power from the input shaft  2  is transmitted to the connecting shaft  5   a  through the transmission gear pair  2   a , the driven gears  6   b ,  7   b  of the first gear pairs  6 ,  7  rotate, and the fourth outer ring  42  (refer to  FIG. 2 ) of the fourth clutch  40  and the sixth inner ring  61  of the sixth clutch  60  rotate. The fourth outer ring  42  of the fourth clutch  40  rotates toward the lock direction (the arrow Ro direction of  FIG. 5 ) when viewed from the fourth inner ring  41  side in relative rotation with respect to the fourth inner ring  41 , however, because the load application device  15  (refer to  FIG. 4 ) of the fourth clutch  40  of the first gear pair  7  has been operated (ON), the fourth outer ring  42  (refer to  FIG. 2 ) of the fourth clutch  40  of the first gear pair  7  makes the fourth inner ring  41  of the fourth clutch  40  idly rotate. In contrast to this, because the load application device  15  of the fourth clutch  40  of the first gear pair  6  is in the non-operated state (OFF), the power is transmitted from the fourth outer ring  42  (refer to  FIG. 2 ) of the fourth clutch  40  of the first gear pair  6  to the fourth inner ring  41 , and the output shaft  5   b  rotates. The rotational speed of the output shaft  5   b  is al which is equal with the rotational speed of the driven gear  6   b  of the first gear pair  6 . 
         [0075]    On the other hand, in this case, the driving gear  8   a  is rotated by the output shaft  5   b  through the driven gear  8   b . In the present embodiment, because the gear ratio (teeth number of driven gear/teeth number of driving gear) k 3  of the second gear pair  8  is set to be less than the gear ratio k 1  of the first gear pair  6 , the rotational speed (α 1 ·k 3 =k 3 /k 1 ·α) of the driving gear  8   a  of the second gear pair  8  becomes less than the rotational speed (α) of the input shaft  2 . Therefore, in the sixth clutch  60 , the rotational speed of the sixth outer ring  62  (refer to  FIG. 2 ) becomes slower than the rotational speed a of the sixth inner ring  61 , which is same with the condition in which the sixth outer ring  62  relatively rotates toward the free direction (the counter-arrow Ro direction of  FIG. 5 ). Accordingly, in the sixth clutch  60 , the sixth sprags  63  cannot engage with the sixth inner ring  61  and the sixth outer ring  62 , and the sixth outer ring  62  makes the sixth inner ring  61  idly rotate. Thus, rotation of the output shaft  5   b  (rotational speed: al) is transmitted to the front wheels  101 , and the vehicle  100  travels forward. 
         [0076]    Also, because the power transmitting device  1  includes the fifth clutch  50  blocking transmission of the power from the engine  111  to the switching device  4 , by releasing connection of the fifth clutch  50 , the vehicle  100  can travel by the driving force of the generator motor  112  only. Thus, the fuel consumption of the engine  111  can be suppressed. In this case, in order to further suppress the fuel consumption, it is also possible to stop the engine  111  and to stop operation of a valve (not shown) of the engine  111 . 
         [0077]    Next, the power transmitting device  1  in high speed traveling when the vehicle travels by only the driving force of the engine  111  will be described.  FIG. 9  is a schematic view schematically showing the internal structure of the power transmitting device  1  in high speed traveling when the vehicle travels by only the driving force of the engine  111 . In high speed traveling, under the state described in  FIG. 8  (the state of travel assisting by the generator motor  112 ), the generator motor  112  is stopped. Although the first outer ring  12  (refer to  FIG. 2 ) of the first clutch  10  rotates toward the lock direction (the arrow Ro direction of  FIG. 5 ) when viewed from the first inner ring  11  side in relative rotation with respect to the first inner ring  11  by the power transmitted to the input shaft  2  from the engine  111 , because the load application device  15  (refer to  FIG. 4 ) of the first clutch  10  has been operated, the first outer ring  12  of the first clutch  10  makes the first inner ring  11  idly rotate. Also, in the second clutch  20 , because the second outer ring  22  (refer to  FIG. 2 ) rotates toward the free direction (the counter-arrow Ro direction of  FIG. 5 ) when viewed from the second inner ring  21  side in relative rotation with respect to the second inner ring  21 , the second outer ring  22  makes the second inner ring  21  idly rotate. Accordingly, transmission of the power from the input shaft  2  to the generator motor  112  is blocked, and only the power of the engine  111  is transmitted from the input shaft  2  to the change gear  5 . 
         [0078]    As a result, even when the number of revolution of the input shaft  2  increases by increase of the vehicle speed and increase of the number of revolution of the engine  111 , because the rotor  112   r  is not interlocked, the generator motor  112  does not require the strength sufficient to support high speed rotation of the rotor  112   r , and therefore the generator motor  112  can be miniaturized and reduced in weight. Also, because rotation of the rotor  112   r  in high speed traveling when the vehicle travels by only the driving force of the engine  111  can be prevented, the event that the internal resistance and the inertia of the generator motor  112  become the driving resistance and the energy loss is caused can be prevented, and energy can be utilized effectively. 
         [0079]    Also, when shift-up speed change is to be performed, as shown in  FIG. 9 , operation of the load application device  15  (refer to  FIG. 4 ) of the fourth clutch  40  of the first gear pair  7  on the high stage side of the first gear pair  6  is stopped (OFF). As a result, similarly to the fourth clutch  40  of the first gear pair  6 , the fourth clutch  40  of the first gear pair  7  also become the state the fourth sprags  43  can engage with the fourth inner ring  41  (refer to  FIG. 2 ) and the fourth outer ring  42 . 
         [0080]    Here, because the rotational speed α 2  of the driven gear  7   b  of the first gear pair  7  is faster than the rotational speed α 1  of the driven gear  6   b  of the first gear pair  6  (α 1 &lt;α 2 ), the rotational speed α 2  of the driven gear  7   b  comes to exceed the rotational speed (α 1 ) of the output shaft  5   b . Accordingly, in the fourth clutch  40  of the first gear pair  7 , the fourth outer ring  42  (refer to  FIG. 2 ) rotates toward the lock direction (the arrow Ro direction of  FIG. 5 ) when viewed from the fourth inner ring  41  side in relative rotation with respect to the fourth inner ring  41 . As a result, the power is transmitted from the fourth outer ring  42  toward the fourth inner ring  41 , the driven gear  7   b  rotates with the output shaft  5   b , and the output shaft  5   b  rotates at the rotational speed of α 2 . 
         [0081]    On the other hand, the rotational speed (α 1 ) of the driven gear  6   b  of the first gear pair  6  becomes slower than the rotational speed (α 2 ) of the output shaft  5   b  (α 1 &lt;α 2 ). Accordingly, in the fourth clutch  40  of the first gear pair  6 , the rotational speed of the fourth outer ring  42  becomes slower than the rotational speed of the fourth inner ring  41  which is same with the state the fourth inner ring  41  relatively rotates toward the free direction (the counter-arrow Ri direction of  FIG. 5 ). Therefore, in the fourth clutch  40  of the first gear pair  6 , the fourth sprags  43  cannot engage with the fourth inner ring  41  and the fourth outer ring  42 . As a result, the driven gear  6   b  makes the output shaft  5   b  idly rotate, and the power is not transmitted. Also, because the sixth outer ring  62  (refer to  FIG. 2 ) of the sixth clutch  60  rotates toward the free direction (the counter-arrow Ro direction of  FIG. 5 ) when viewed from the sixth inner ring  61  side in relative rotation with respect to the sixth inner ring  61  through the driven gear  8   b  that is integral with the output shaft  5   b , the sixth outer ring  62  makes the sixth inner ring  61  idly rotate, and the power is not transmitted. 
         [0082]    Thus, when shift-up speed change is to be performed, the speed change is achieved by only stopping operation of the load application device  15  of the fourth clutch  40  of the first gear pair  7  on the high stage side without any operation on the low stage side (the first gear pair  6  in the present embodiment). Also, in the fourth clutch  40  of the first gear pair  7 , by stopping operation of the load application device  15 , the fourth sprags  43  tilt toward the self-lock direction, and relative rotation toward a specific direction with respect to the fourth inner ring  41  and the fourth outer ring  42  is restricted instantly. Accordingly, the time required for switching can be shortened, and quick speed change is achieved. Also, because the time required for switching can be shortened, the fourth inner ring  41  and the fourth outer ring  42  do not idly rotate relative to each other during the time from when they are in the state not transmitting the power until when they become the state transmitting the power, and the impact in changing the speed can be prevented. 
         [0083]    Further, because the speed change is allowed by only switching operation and non-operation of the load application device  15  of the fourth clutch  40 , a complicated meshing mechanism, shift forks and the like are not required, and weight reduction and miniaturization can be achieved. Thus, a number of first gear pairs can be accommodatingly mounted inside a limited space of the change gear  5 , and a multi-stage power transmitting device  1  of six-speeds or more for example can be achieved. 
         [0084]    Also, in shift-up speed changing, although the traveling speed of the vehicle  100  remains unchanged between before and after the speed change, the gear ratio changes between the gear pairs of the high speed stage and the low speed stage, therefore due to the effect of the internal resistance and the inertia of the engine  111 , the number of revolution of the engine  111  drops after the speed change, and the speed change shock occurs. In order to prevent it, it is preferable to change the speed after the number of revolution of the engine  111  is dropped to a number of revolution matching the gear pair of the high speed stage. However, a certain time becomes necessary to drop the number of revolution of the engine  111 , and, as a result, there were problems that the shift-up time became long and deceleration feeling was caused. 
         [0085]    On the other hand, the power transmitting device  1  can drop the number of revolution of the engine  111  in a short time in shifting up, and shift-up can be performed in a short time without causing the deceleration feeling. The case the number of revolution of the engine  111  is dropped in shifting up will be described referring to  FIG. 10 .  FIG. 10  is a schematic view schematically showing the internal structure of the power transmitting device  1  in shifting up. 
         [0086]    When the shift-up speed change for transmitting the power by the first gear pair  7  is to be performed in the state the power is transmitted by the first gear pair  6  and the vehicle is traveling (the load application device of the fourth clutch  40  of the first gear pair  6  is OFF, and the load application device of the fourth clutch  40  of the first gear pair  7  is ON), the load application device  15  (refer to  FIG. 2 ) of the first clutch  10  is made a non-operated state (OFF) under the state the fifth clutch  50  is connected. As a result, the first outer ring  12  (refer to  FIG. 2 ) of the first clutch  10  rotates toward the lock direction (the arrow Ro direction of  FIG. 5 ) when viewed from the first inner ring  11  side in relative rotation with respect to the first inner ring  11 , and, in the second clutch  20 , the second outer ring  22  (refer to  FIG. 2 ) rotates toward the free direction (the counter-arrow Ri direction of  FIG. 6 ) when viewed from the second inner ring  21  side in relative rotation with respect to the second inner ring  21 . Therefore, the first inner ring  11  of the first clutch  10  rotates with the first outer ring  12 . Accompanying rotation of the first outer ring  12 , the carrier  80   c  rotates, and the sun gear  80   s  meshing with the planetary gear  80   p  rotates. As a result, the power is transmitted from the sun gear  80   s  to the transmission shaft  3 , the rotor  112   r  rotates, and the electric power is generated. Because a part of the energy transmitted to the input shaft  2  is used and consumed for rotating the rotor  112   r , the number of revolution of the engine  111  connected to the input shaft  2  drops in a short time. 
         [0087]    The number of revolution of the connecting shaft  5   a  connected to the input shaft  2  also drops then. Accompanying it, the number of revolution of the driven gear  6   b  meshing with the driving gear  6   a  drops, and the number of revolution of the fourth outer ring  42  drops. Therefore, in the fourth clutch  40  in the driven gear  6   b , the fourth outer ring  42  (refer to  FIG. 2 ) rotates toward the free direction (the counter-arrow Ro direction of  FIG. 5 ) when viewed from the fourth inner ring  41  side in relative rotation with respect to the fourth inner ring  41 . As a result, transmission of the power from the fourth outer ring  42  to the fourth inner ring  41  is blocked. Therefore, drop of the number of revolution of the driven gear  6   b  does not affect the number of revolution of the output shaft  5   b , that is the traveling speed of the vehicle  100 . Accordingly, the power transmitting device  1  can drop the number of revolution of the input shaft  2   a  (the number of revolution of the engine  111 ) without giving a deceleration feeling of the vehicle  100  to a driver and a fellow passenger. Also, as described in  FIG. 9 , by making the load application device  15  (refer to  FIG. 4 ) of the fourth clutch  40  of the first gear pair  7  a non-operated state (OFF), the shock in shifting up is prevented, and the speed can be changed smoothly in a short time without giving a deceleration feeling. Furthermore, the energy can be utilized effectively, and the electric power generation amount can be increased. 
         [0088]    Next, the power transmitting device  1  in regenerating performed in coast traveling and braking will be described.  FIG. 11  is a schematic view schematically showing the internal structure of the power transmitting device  1  in regenerating. In regenerating, connection of the fifth clutch  50  is released, and the load application device  15  (refer to  FIG. 4 ) of the first clutch  10  is made a non-operated state (OFF). Under the state an accelerator pedal is not operated, as shown in  FIG. 11 , the power is inputted from the output shaft  5   b  (the rotational speed: α 2 ) to the power transmitting device  1 . As a result, the power is transmitted from the output shaft  5   b  to the driving gear  8   a  through the driven gear  8   b  of the second gear pair  8 , and the power is transmitted to the sixth outer ring  62  (refer to  FIG. 2 ) of the sixth clutch  60 . 
         [0089]    Here, because the gear ratio of the second gear pair  8  is k 3  and the rotational speed of the driven gear  8   b  is α 2 , the rotational speed of the sixth outer ring  62  which is integral with the driving gear  8   a  is k 3 ·α 2 . On the other hand, because the sixth inner ring  61  of the sixth clutch  60  is in the state the driving force from the connecting shaft  5   a  is not applied, its rotational speed is slower than the rotational speed of the driving gear  8   a . As a result, the sixth outer ring  62  rotates toward the lock direction (the arrow Ro direction of  FIG. 5 ) when viewed from the sixth inner ring  61  side in relative rotation with respect to the sixth inner ring  61 . When the load application device  15  of the sixth clutch  60  is not operated (OFF), the sixth sprags  63  engage with the sixth outer ring  62  and the sixth inner ring  61 . As a result, the power is transmitted from the sixth outer ring  62  of the sixth clutch  60  toward the sixth inner ring  61 , and the driving gear  8   a  rotates with the connecting shaft  5   a  (rotational speed: k 3 ·α 2 ). Accompanying rotation of the driving gear  8   a , the connecting shaft  5   a  rotates, and the driving gears  6   a ,  7   a  of the first gear pairs  6 ,  7  also rotate (rotational speed: k 3 ·α 2 ). 
         [0090]    As a result, the power is transmitted to the driven gears  6   b ,  7   b  that mesh with the driving gears  6   a ,  7   a  of the first gear pairs  6 ,  7 , and the driven gears  6   b ,  7   b  rotate at speeds matching respective gear ratios. The rotational speed β 2  of the driven gear  6   b  is k 3 /k 1 ·α 2 , and the rotational speed β 2  of the driven gear  7   b  is k 3 /k 2 ·α 2 . Because of the relation k 1 &gt;k 2 &gt;k 3 , both of the rotational speeds β 1 , β 2  of the driven gears  6   b ,  7   b  become lower than α 2 . 
         [0091]    On the other hand, because the rotational speed of the output shaft  5   b  is α 2 , in the fourth clutch  40  of the first gear pair  7 , the fourth inner ring  41  rotates at the speed α 2 . Therefore, in the fourth clutch  40  of the first gear pair  7 , the rotational speed of the fourth inner ring  41  becomes faster than the rotational speed of the fourth outer ring  42  which is a state same with the state the fourth inner ring  41  relatively rotates toward the free direction (the counter-arrow Ri direction of  FIG. 5 ). This happens similarly in the first gear pair  6  also. Therefore, in the fourth clutch  40  of the first gear pairs  6 ,  7 , the fourth sprags  43  cannot engage with the fourth inner ring  41  and the fourth outer ring  42 . Accordingly, under the state the load application devices  15  of the fourth clutch  40  of the first gear pairs  6 ,  7  are not operated (OFF), the power from the output shaft  5   b  can be transmitted to the connecting shaft  5   a.    
         [0092]    The power transmitted to the connecting shaft  5   a  is transmitted to the input shaft  2  through the transmission gear pair  2   a . When the power is transmitted to the input shaft  2 , the first outer ring  12  (refer to  FIG. 2 ) of the first clutch  10  rotates toward the lock direction (the arrow Ro direction of  FIG. 5 ) when viewed from the first inner ring  11  side in relative rotation with respect to the first inner ring  11 , and in the second clutch  20 , the second outer ring  22  (refer to  FIG. 2 ) rotates toward the free direction (the counter-arrow Ri direction of  FIG. 6 ) when viewed from the second inner ring  21  side in relative rotation with respect to the second inner ring  21 . Therefore, the first inner ring  11  of the first clutch  10  rotates with the first outer ring  12 . Accompanying rotation of the first inner ring  11  of the first clutch  10 , the carrier  80   c  rotates, and the sun gear  80   s  meshing with the planetary gear  80   p  rotates. As a result, the power is transmitted from the sun gear  80   s  to the transmission shaft  3 , the rotor  112   r  rotates, and the electric power is generated. 
         [0093]    Thus, the generator motor  112  is allowed to function as a power generator by the power inputted from the output shaft  2 , and the electric power generated by the generator motor  112  can be regenerated to an electric power source. Also, because the fifth clutch  50  blocking transmission of the power from the engine  111  to the switching device  4  is provided, by separating the engine  111  from the switching device  4  in regenerating, the engine  111  can be prevented from becoming the driving resistance of the generator motor  112 , the energy loss can be eliminated, and the regeneration amount can be increased. 
         [0094]    Next, a power transmitting device  70  in a second embodiment of the present invention will be described referring to  FIG. 12 . In the first embodiment, the case in which the power transmitting device was mounted on the front-wheel-drive vehicle  100  was described. On the other hand, in the second embodiment, the power transmitting device  70  is mounted on a rear-wheel-drive vehicle  200 .  FIG. 12  is a schematic view schematically showing the vehicle  200  mounting the power transmitting device  70  in the second embodiment of the present invention. Also, arrows F-B, L-R of  FIG. 12  show the front-rear direction and the left-right direction of the vehicle  200  respectively. 
         [0095]    First, the constitution outline of the vehicle  200  will be described. As shown in  FIG. 12 , the vehicle  200  includes a rear unit  120  driving rear wheels  102  (a left rear wheel  102 FL and a right rear wheel  102 FR). The rear unit  120  mainly includes the engine  111  and the generator motor  112  as power sources and the power transmitting device  70  transmitting the power of the engine  111  and the generator motor  112  to the rear wheels  102 , and is constituted so that the power transmitted to the output shaft  2  of the power transmitting device  70  is transmitted to the right and left rear wheels  102  through a differential device. 
         [0096]    Next, the power transmitting device  70  in the second embodiment will be described referring to  FIG. 13 .  FIG. 13  is a schematic view schematically showing the internal structure of the power transmitting device  70  in the second embodiment. Below, with respect to a portion same with the corresponding portion of the first embodiment, a same reference numeral is put and description thereof will be omitted. Also, in  FIG. 13 , in order to facilitate understanding, only the constitutions assuming the function of transmitting the power are illustrated. 
         [0097]    Unlike the power transmitting device  1  in the first embodiment, as shown in  FIG. 13 , in the power transmitting device  70 , a third clutch  30  is disposed in the input shaft  2  between the switching device  4  and the transmission gear pair  2   a . The third clutch  30  is for blocking transmission of the power from the input shaft  2  to a change gear  71 . Also, the power transmitting device  1  in the first embodiment included the change gear  5  having the fourth clutch  40  and the sixth clutch  60 , however, the power transmitting device  70  in the second embodiment differs in including the change gear  71  instead of the change gear  5 . 
         [0098]    Also, in the power transmitting device  1  in the first embodiment, the first inner ring  11  of the first clutch  10  and the second inner ring  21  of the second clutch  20  were connected to the carrier  80   c , and the first outer ring  12  of the first clutch  10  and the second outer ring  22  of the second clutch  20  were connected to the input shaft  2 . On the other hand, the power transmitting device  70  in the second embodiment differs in that the first inner ring  11  of the first clutch  10  and the second inner ring  21  of the second clutch  20  are connected to the input shaft  2  and that the first outer ring  12  of the first clutch  10  and the second outer ring  22  of the second clutch  20  are connected to the carrier  80   c . However, the constitutions themselves of the first clutch  10  and the second clutch  20  are similar, and the first clutch  10  is a clutch blocking transmission of the power from the transmission shaft  3  to the input shaft  2  while blockably transmitting the power inputted from the input shaft  2  to the transmission shaft  3 . Also, the second clutch  20  is a clutch transmitting the power inputted from the transmission shaft  3  to the input shaft  2  while blocking transmission of the power from the input shaft  2  to the transmission shaft  3 , which are similar to what was described in the first embodiment, and therefore detailed description on the motion of the first clutch  10  and the second clutch  20  will be omitted. 
         [0099]    The change gear  71  in the power transmitting device  70  does not include the fourth clutch  40  and the sixth clutch  60 , and includes a connecting shaft  71   a  connected to the input shaft  2  through the transmission gear pair  2   a , an output shaft  71   b  disposed in parallel with the connecting shaft  71   a , and plural first gear pairs  72 ,  73  disposed on the output shaft  71   b  and the connecting shaft  71   a  and set to mesh with each other and to make gear ratios different with each other. The first gear pairs  72 ,  73  include driving gears  72   a ,  73   a  disposed on the connecting shaft  71   a  and driven by the power transmitted from the input shaft  2 , and driven gears  72   b ,  73   b  disposed on the output shaft  71   b  and followingly driven by the driving gears  72   a ,  73   a . Also, in the change gear  71 , a meshing mechanism, shift forks and the like are omitted in the illustration. Further, the reverse travel stage is also omitted in the illustration. In the reverse travel stage, a pinion gear can be inserted between the first gear pairs  72 ,  73 . 
         [0100]    Next, the operating state of the power transmitting device  70  in the second embodiment constituted as described above will be described referring to  FIG. 14  through to  FIG. 17 .  FIG. 14  through to  FIG. 17  schematically show the front views of the internal structure of the power transmitting device  70 . Here, in  FIG. 14  and  FIG. 17 , in order to facilitate understanding, the transmission route of the power is shown by an arrow P, and respective rotational directions of the driving gears  72   a ,  73   a , the driven gears  72   b ,  73   b , the first inner ring  11  of the first clutch  10 , and the second inner ring  21  of the second clutch  20  are shown in the arrows. Also, the case the load application device  15  (refer to  FIG. 4 ) of the first clutch  10  is operated and engagement of the first sprags  13  with the first inner ring  11  (refer to  FIG. 13 ) and the first outer ring  12  is released is described as “ON”, whereas the case the load application device  15  of the first clutch  10  is made a non-operated state and the first sprags  13  can engage with the first inner ring  11  and the first outer ring  12  is described as “OFF”. 
         [0101]    First, the power transmitting device  70  in starting the engine  111  will be described referring to  FIG. 14 .  FIG. 14  is a schematic view schematically showing the internal structure of the power transmitting device  70  in starting the engine  111 . In starting the engine  111 , connection of the third clutch  30  is released, and the load application device  15  (refer to  FIG. 4 ) of the first clutch  10  is operated (ON). When the generator motor  112  is operated and the rotor  112   r  is rotated, the power is transmitted to the switching device  4  through the step-up gear  80 , the first outer ring  12  (refer to  FIG. 13 ) of the first clutch  10  rotates toward the free direction (the counter-arrow Ro direction of  FIG. 6 ) when viewed from the first inner ring  11  side in relative rotation with respect to the first inner ring  11 , and the second outer ring  22  (refer to FIG.  13 ) of the second clutch  20  rotates toward the lock direction (the arrow Ro direction of  FIG. 5 ) when viewed from the second inner ring  21  side in relative rotation with respect to the second inner ring  21 . Accompanying rotation of the second outer ring  22  of the second clutch  20 , the second inner ring  21  rotates. Because connection of the third clutch  30  has been released, the input shaft  2  rotates accompanying the rotation of them. As a result, the engine  111  is rotated, and the engine  111  starts. Accordingly, even when a cell motor (starter) is not mounted, the generator motor  112  can transmit the power to the engine  111  from the input shaft  2  through the second clutch  20 , and the engine  111  can be started. 
         [0102]    When the engine  111  starts and the input shaft  2  is driven by the engine  111 , the second inner ring  21  (refer to  FIG. 13 ) of the second clutch  20  rotates toward the free direction (the counter-arrow Ri direction of  FIG. 5 ) when viewed from the second outer ring  22  side in relative rotation with respect to the second outer ring  22 . Also, by rotation of the input shaft  2 , the first inner ring  11  of the first clutch  10  rotates toward the lock direction (the arrow Ri direction of  FIG. 6 ) when viewed from the first outer ring  12  side in relative rotation with respect to the first outer ring  12 , however, because the load application device  15  of the first clutch  10  has been operated, the first inner ring  11  idly rotates inside the first outer ring  12 . Accordingly, after the engine  111  starts, the power from the input shaft  2  to the transmission shaft  3  is blocked. In a similar manner, when the number of revolution of the engine  111  is increased also, transmission of the power from the input shaft  2  to the transmission shaft  3  is blocked. Therefore, because the generator frame does not require the strength sufficient to support high speed rotation of the rotor  112   r , the generator motor  112  can be miniaturized and reduced in weight. Also, because transmission of the power from the input shaft  2  to the change gear  71  is blocked by the third clutch  30 , vibration of the engine  111  in starting can be made hardly be propagated to a vehicle body. 
         [0103]    Here, although it is not illustrated in  FIG. 14 , connection of the third clutch  30  is released and the load application device  15  (refer to  FIG. 4 ) of the first clutch  10  is made a non-operated state (OFF) under the state the engine  111  is driven. As a result, the first inner ring  11  (refer to  FIG. 13 ) of the first clutch  10  rotates toward the lock direction (the arrow Ri direction of  FIG. 6 ) when viewed from the first outer ring  12  side in relative rotation with respect to the first outer ring  12 , and, in the second clutch  20 , the second inner ring  21  (refer to  FIG. 13 ) rotates toward the free direction (the counter-arrow Ri direction of  FIG. 5 ) when viewed from the second outer ring  22  side in relative rotation with respect to the second outer ring  22 . Therefore, the first outer ring  12  of the first clutch  10  rotates with the first inner ring  11 . Accompanying rotation of the first outer ring  12  of the first clutch  10 , the carrier  80   c  rotates and the sun gear  80   s  meshing with the planetary gear  80 P rotates. As a result, the power is transmitted from the sun gear  80   s  to the transmission shaft  3 , the rotor  112   r  rotates, and the electric power is generated. Thus, by blocking transmission of the power from the input shaft  2  to the change gear  71  by the third clutch  30 , all the power from the engine  111  can be transmitted to the rotor  112   r , and the electric power can be generated using the generator motor  112 . 
         [0104]    Next, the power transmitting device  70  in travel assisting when the driving force of the engine  111  is assisted by the driving force of the generator motor  112  will be described referring to  FIG. 15 .  FIG. 15  is a schematic view schematically showing the internal structure of the power transmitting device  70  in travel assisting by the generator motor  112 . In travel assisting by the generator motor  112 , the third clutch  30  is connected, and the operated state of the load application device  15  (refer to  FIG. 4 ) of the first clutch  10  is maintained (ON). When the power from the engine  111  is transmitted to the input shaft  2 , the first inner ring  11  (refer to  FIG. 13 ) of the first clutch  10  rotates toward the lock direction (the arrow Ri direction of  FIG. 6 ) when viewed from the first outer ring  12  side in relative rotation with respect to the first outer ring  12 . 
         [0105]    However, because the load application device  15  of the first clutch  10  has been operated, the first inner ring  11  of the first clutch  10  idly rotates inside the first outer ring  12 . Also, in the second clutch  20 , because the second inner ring  21  (refer to  FIG. 13 ) rotates toward the free direction (the counter-arrow Ri direction of  FIG. 5 ) when viewed from the second outer ring  22  side in relative rotation with respect to the second outer ring  22 , the second inner ring  21  of the second clutch  20  also idly rotates inside the second outer ring  22 . Therefore, transmission of the power from the input shaft  2  to the generator motor  112  is blocked. 
         [0106]    On the other hand, when the generator motor  112  is driven and the power from the rotor  112   r  is transmitted to the switching device  4 , the first outer ring  12  (refer to  FIG. 13 ) of the first clutch  10  rotates toward the free direction (the counter-arrow Ro direction of  FIG. 6 ) when viewed from the first inner ring  11  side in relative rotation with respect to the first inner ring  11 , and the second outer ring  22  (refer to  FIG. 13 ) of the second clutch  20  rotates toward the lock direction (the arrow Ro direction of  FIG. 5 ) when viewed from the second inner ring  21  side in relative rotation with respect to the second inner ring  21 . Because relative rotational direction of the first outer ring  12  of the first clutch  10  is the free direction, the first outer ring  12  of the first clutch  10  makes the first inner ring  11  idly rotate. On the other hand, by rotation of the second outer ring  22  of the second clutch  20 , the second inner ring  21  rotates, and, accompanying it, the input shaft  2  rotates. Therefore, the power of the engine  111  and the generator motor  112  is transmitted to the input shaft  2 . When the power from the input shaft  2  is transmitted to the connecting shaft  71   a  through the transmission gear pair  2   a , the vehicle  100  travels by meshing of the first gear pairs  72 ,  73  of a desired shift stage in the change gear  71 . 
         [0107]    Next, the power transmitting device  70  in high speed traveling when the vehicle travels by only the driving force of the engine  111  will be described.  FIG. 16  is a schematic view schematically showing the internal structure of the power transmitting device  70  in high speed traveling when the vehicle travels by only the driving force of the engine  111 . In high speed traveling, under the state described in  FIG. 15  (the state of travel assisting by the generator motor  112 ), the generator motor  112  is stopped. Although the first inner ring  11  (refer to  FIG. 13 ) of the first clutch  10  rotates toward the lock direction (the arrow Ri direction of  FIG. 6 ) when viewed from the first outer ring  12  side in relative rotation with respect to the first outer ring  12  by the power transmitted to the input shaft  2 , because the load application device  15  (refer to  FIG. 4 ) of the first clutch  10  has been operated, the first inner ring  11  idly rotates inside the first outer ring  12 . Also, in the second clutch  20 , because the second inner ring  21  (refer to  FIG. 13 ) rotates toward the free direction (the counter-arrow Ri direction of  FIG. 5 ) when viewed from the second outer ring  22  side in relative rotation with respect to the second outer ring  22 , the second inner ring  21  also idly rotates inside the second outer ring  22 . Therefore, transmission of the power from the input shaft  2  to the generator motor  112  is blocked, and the power is transmitted from the input shaft  2  to the change gear  71 . 
         [0108]    As a result, because the generator motor  112  does not require the strength sufficient to support high speed rotation of the rotor  112   r , the generator motor  112  can be miniaturized and reduced in weight. Also, because rotation of the rotor  112   r  in high speed traveling when the vehicle travels by only the driving force of the engine  111  can be prevented, the event that the internal resistance and the inertia of the generator motor  112  become the driving resistance and the energy loss is caused can be prevented, and the energy can be utilized effectively. 
         [0109]    Next, the power transmitting device  70  in regenerating will be described.  FIG. 17  is a schematic view schematically showing the internal structure of the power transmitting device  70  in regenerating. In regenerating, the third clutch  30  is connected, and the load application device  15  (refer to  FIG. 4 ) of the first clutch  10  is made a non-operated state (OFF). Under the state the accelerator pedal is not operated, the power is transmitted from the output shaft  71   b  toward the input shaft  2 . When the power is transmitted to the input shaft  2 , the first inner ring  11  (refer to  FIG. 13 ) of the first clutch  10  rotates toward the lock direction (the arrow Ri direction of  FIG. 6 ) when viewed from the first outer ring  12  side in relative rotation with respect to the first outer ring  12 , and, in the second clutch  20 , the second inner ring  21  (refer to  FIG. 13 ) rotates toward the free direction (the counter-arrow Ri direction of  FIG. 5 ) when viewed from the second outer ring  22  side in relative rotation with respect to the second outer ring  22  and idly rotates. Therefore, the first outer ring  12  of the first clutch  10  rotates with the first inner ring  11 . Accompanying rotation of the first outer ring  12  of the first clutch  10 , the carrier  80   c  of the step-up gear  80  rotates, and the sun gear  80   s  meshing with the planetary gear  80 P rotates. As a result, the power is transmitted from the sun gear  80   s  to the transmission shaft  3 , the rotor  112   r  rotates, and the electric power is generated. 
         [0110]    Next, a power transmitting device  74  in a third embodiment will be described referring to  FIG. 18 .  FIG. 18  is a schematic view schematically showing the power transmitting device  74  in the third embodiment. The power transmitting device  74  is mounted on the front-wheel-drive vehicle  100  described in the first embodiment. The power transmitting device  74  differs from the power transmitting device  1  in the first embodiment in that the switching device  4  and the fifth clutch  50  described in the first embodiment are not provided. Also, with respect to a portion same with the corresponding portion of the first embodiment, a same reference numeral is put, and description thereof will be omitted. 
         [0111]    As shown in  FIG. 18 , in the power transmitting device  74 , the carrier  80   c  of the step-up gear  80  (the ring gear  80   r  is fixed unrotatably to a case  74   a  of the power transmitting device  74 ) is connected to the input shaft  2  not through the switching device  4 . In order to start the engine  111 , the generator motor  112  is rotated under the state the load application device  15  (refer to  FIG. 4 ) of the fourth clutch  40  has been operated. Because its power is transmitted to the input shaft  2  through the step-up gear  80 , the engine  111  is rotated, and the engine  111  can be started. Also, because transmission of the power is blocked in the fourth clutch  40  by operating the load application device  15  (refer to  FIG. 4 ) of the fourth clutch  40 , the wheels  101  can be prevented from rotating. 
         [0112]    In order to start the vehicle  100 , the fourth sprags  43  can be tilted toward the self-lock direction by the energizing force of the ribbon spring  16  by stopping operation of the load application device  15  (refer to  FIG. 4 ) of the fourth clutch  40 . As a result, the power is transmitted to the output shaft  5   b . Thus, the power from the engine  111  can be transmitted to the output shaft  5   b , and the vehicle  100  can be started. Therefore, the processes from the start of the engine till the start of the vehicle  100  can be performed by simple control of switching the load application device  15  of the fourth clutch  40  between operation and non-operation, and the time from the start of the engine till the start of the vehicle  100  can be shortened. 
         [0113]    Also, shift-up speed change and shift-down speed change can be performed in a manner similar to that in the first embodiment. Also, in coast traveling and braking, regeneration can be performed also in a manner similarly to that in the first embodiment. Because the motion of the power transmitting device  74  in these cases is similar to that described in the first embodiment, description will be omitted. The power transmitting device  74  can achieve respective functions of starting the engine  111 , starting the vehicle  100 , speed changing, and regenerating by a simplified structure not provided with the switching device  4 . Also, the power transmitting device  74  may possibly be mounted on a rear-wheel-drive vehicle  200 . 
         [0114]    The present invention was described as above based on the embodiments, however the present invention is not limited to the embodiments by any means, and it can be easily surmised that a variety of improvements and alterations are possible within the range not departing from the purpose of the present invention. 
         [0115]    In the respective embodiments, the case the load application device  15  (the actuator  15   a ) was constituted by the motor (AC motor or DC motor) was described, however, it is not necessarily limited to this, and other power sources can rightly be adopted. As the other power sources, for example, a DC motor, hydraulic motor, pneumatic cylinder, hydraulic cylinder, AC solenoid, DC solenoid and the like can be exemplarily cited. 
         [0116]    Here, when the actuator  15   a  is constituted by the solenoid, the case is not limited to apply the load to the sprags  13  by a gear mechanism and the like, but, for example, the constitution of applying the load to the sprags  13  utilizing an electro-magnetic force is also possible. 
         [0117]    In the first embodiment, the case the fourth clutch  40  was arranged on the output shaft  5   b  and the sixth clutch  60  was arranged on the connecting shaft  5   a  was described, however, the first embodiment is not necessarily limited to this, and the fourth clutch  40  can be rightly arranged in either of the output shaft  5   b  and the connecting shaft  5   a.    
         [0118]    In the respective embodiments, the case the step-up gear  80  was constituted by a planetary gear device was described, however, it is not necessarily limited to this, and a gear device other than the planetary gear device can be rightly used. 
         [0119]    In the respective embodiments, the case the first clutch  10  was constituted so as to include a sprag type one-way clutch with the function of releasing the first sprags  13  was described, however, it is not necessarily limited to this. As far as the power is transmitted to a specific direction and the function of blocking transmission of the power is provided, other clutches can be used. As the other clutches, a clutch transmitting the power by rollers and the like can be cited. 
         [0120]    Although the power transmitting device  1  in the first embodiment does not include the third clutch  30  disposed on the power transmission route from the switching device  4  to the change gear  5 , as described in the second embodiment, it is possible to arrange the third clutch  30  on the input shaft  2 . By providing the third clutch  30 , transmission of the power from the engine  111  to the change gear  71  can be blocked, the vibration of the engine  111  in starting can be made hardly be propagated to the vehicle body, and the comfortability can be improved. 
         [0121]    Although the description was omitted in the first embodiment, it is also possible that the load application device  15  of the fourth clutch  40  of the first gear pair  6  on the low stage side is operated after the shift-up speed change is performed and engagement of the fourth sprags  43  with the fourth inner ring  41  and the fourth outer ring  42  is forcibly released. 
         [0122]    In the second embodiment, the case the change gear  71  included a gear type speed change mechanism was described, however, it is not necessarily limited to this, and other change gears can be used. As the other change gears, a continuously variable change gear of a belt type and the like, a manual change gear and the like can be cited for example. 
       REFERENCE SIGNS LIST 
       [0000]    
       
         
           
               1 ,  70 ,  74  Power transmitting device 
               2  Input shaft 
               3  Transmission shaft 
               4  Switching device 
               5 ,  71  Change gear 
               5   a ,  71   a  Connecting shaft 
               5   b ,  71   b  Output shaft 
               6 ,  7 ,  72 ,  73  First gear pair 
               8  Second gear pair 
               10  First clutch 
               11  First inner ring (inner ring) 
               11   a  Outer peripheral surface 
               12  First outer ring (outer ring) 
               12   a  Inner peripheral surface 
               13  First sprags (sprags) 
               13   a ,  13   b  Engaging surface 
               14  Retainer 
               15  Load application device 
               16  Ribbon spring (energizing member) 
               20  Second clutch 
               30  Third clutch 
               40  Fourth clutch 
               41  Fourth inner ring (inner ring) 
               42  Fourth outer ring (outer ring) 
               43  Fourth sprags (sprags) 
               50  Fifth clutch 
               80  Step-up gear 
               111  Engine 
               112  Generator motor 
               112   r  Rotor 
             A, B Contact point 
             O Axis
Provided is a power transmitting device that lets a motor in a hybrid vehicle be smaller and lighter, prevents internal resistance and inertia of the generator motor from becoming driving resistance, and can effectively utilize energy. Via a first clutch ( 10), power is transmitted from an input shaft ( 2) to a transmission shaft ( 3) but power transmission from the transmission shaft ( 3) to the input shaft ( 2) is blocked, and power transmission from the input shaft ( 2) to the transmission shaft ( 3) can be blocked. Via a second clutch ( 20), power is transmitted from the transmission shaft ( 3) to the input shaft ( 2), while power transmission from the input shaft ( 2) to the transmission shaft ( 3) is blocked. Thus, when driving using only the power of the engine ( 111), power transmission from the input shaft ( 2) to the transmission shaft ( 3) is blocked, thereby preventing transmission of power to a generator motor ( 112). Consequently, the generator motor ( 112) can be made smaller and lighter, and energy losses can be prevented.