Title of Invention: Parking device Abstract: A hydraulic unit and an electromagnetic unit are disposed in directions that are orthogonal to each other. In addition, in a parking locked state, a roller of a pin of a piston rod and a lower abutment surface of a distal end portion of a solenoid shaft are in abutment with each other. Further, when a coil is not energized, the solenoid shaft is allowed to be moved rightward in the drawing through abutment between the pin of the piston rod and the distal end portion of the solenoid shaft during movement of the piston rod. Detailed Description: Part general_description_paragraphs: Part CROSS REFERENCE TO RELATED APPLICATIONS: This application is a National Stage of International Application No. PCT/JP2014/066042 filed Jun. 17, 2014, claiming priority based on Japanese Patent Application Nos. +1-346-632-3145 filed Jun. 17, 2013 and +1-346-632-3145 filed Oct. 23, 2013, the contents of all of which are incorporated herein by reference in their entirety. Part TECHNICAL FIELD: The present disclosure relates to a parking device, and particularly to a parking device mounted on a vehicle to establish a parking locked state and a parking unlocked state. Part BACKGROUND ART: Hitherto, there has been proposed a parking device of this type, including a locking mechanism including a hydraulic piston 832 and a cylindrical tapered member 858 disposed on the same axis, the hydraulic piston 832 being coupled to a parking rod that operates in conjunction with a parking lock pawl that is engageable with a parking ratchet, and the tapered member 858 being fitted with a plunger of a solenoid 856 as illustrated in FIG. 15 and FIG. 16 which is a cross-sectional view taken along the line X-X of FIG. 15 (see Patent Document 1, for example). FIG. 15 illustrates the locking mechanism in the parking unlocked state. In the parking device, when the tapered member 858 is urged toward the hydraulic piston 832 (leftward in FIG. 15) by a spring 859 in the parking unlocked state, the hydraulic piston 832 is moved leftward in FIG. 15 with lug portions 862 formed on three plates 860 provided around the tapered member 858 pushed outward by the tapered member 858, which establishes the parking locked state. When the hydraulic piston 832 is moved rightward in FIG. 15 by a hydraulic pressure in the parking locked state and the tapered member 858 is pressed against the urging force of the spring 859, meanwhile, the lug portions 862 are closed inward to engage with a catching portion 834 of the hydraulic piston 832, and further the tapered member 858 is fixed in position by the solenoid 856 to lock the hydraulic piston 832 in position, which establishes the parking unlocked state. With such a configuration, the parking unlocked state can be held even when a hydraulic pressure for a hydraulic piston device is reduced with an engine-driven mechanical pump stopped during idle stop. Part RELATED-ART DOCUMENTS: Part Patent Documents: [Patent Document 1] Published Japanese Translation of PCT Application No. 2009-520163 (JP 2009-520163 A) Part SUMMARY OF THE DISCLOSURE: In the parking device discussed above, when switching is performed from the parking unlocked state to the parking locked state, the hydraulic piston is moved until movement of the hydraulic piston is restricted. Therefore, when switching is performed to the parking locked state by a hydraulic pressure thereafter, it is necessary to move the hydraulic piston relatively significantly, and a collision is caused between the hydraulic piston and the lug portions. In the parking device discussed above, in addition, the hydraulic piston, the solenoid, the tapered member, and so forth are provided on the same axis. Therefore, a space is required in the axial direction of the hydraulic piston, which is not suitable in the case where the parking device is disposed in a limited space. In particular, in the case where the parking device is incorporated in FF (front-engine front-drive) vehicles, the mountability of the parking device is an important issue. In order to address such an issue, there is also proposed a parking device in which a solenoid etc. is disposed in a direction that is orthogonal to a shaft of a hydraulic piston. In the parking device, a hook portion is formed at an end portion of a hydraulic piston, and a lug portion is formed at an end portion of a working member that is operable in a direction that is orthogonal to the direction of a shaft of the hydraulic piston by a solenoid attached to a side portion of the shaft of the hydraulic piston. The parking locked state is established by fitting the lug portion with the hook portion with the hydraulic piston moved rightward in the drawing by a hydraulic pressure against the urging force of a spring. Meanwhile, switching from the parking locked state to the parking unlocked state is performed by canceling a hydraulic pressure for the hydraulic piston and operating the working member downward in the drawing using the solenoid to release fitting between the lug portion and the hook portion. With the locking mechanism of the parking lock device, switching from the parking unlocked state to the parking locked state cannot be performed when a hydraulic pressure is not applied to the hydraulic piston. It is a main object of the parking device according to the present disclosure to allow components to be suitably disposed in a limited space, to reduce the amount of movement of a shaft member of a hydraulic unit made when switching is performed from a parking locked state to a parking unlocked state, to suppress occurrence of a collision between the shaft member of the hydraulic unit and a shaft member of an electromagnetic unit, and to establish the parking locked state more adequately. In order to achieve the foregoing main object, the parking device according to the present disclosure adopts the following means. The present disclosure provides a parking device mounted on a vehicle to establish a parking locked state and a parking unlocked state, including: a hydraulic unit that includes a first shaft member that is movable in a first direction, a first elastic member that urges the first shaft member toward a lock side on which the parking locked state is established, in the first direction, using an elastic force, and a hydraulic pressure generation portion that moves the first shaft member toward an unlock side which is opposite to the lock side, in the first direction, using a hydraulic pressure against the elastic force of the first elastic member; and an electromagnetic unit that includes a second shaft member that is movable in a second direction which is orthogonal to the first direction, a second elastic member that urges the second shaft member toward the first shaft member, in the second direction, using an elastic force, and a magnetic force holding portion that can hold the second shaft member on a side of the first shaft member using a magnetic force, in which: the first shaft member is provided with an abutment portion that can abut against a distal end portion of the second shaft member; a lock side surface of the distal end portion of the second shaft member on the lock side is formed to be inclined toward the lock side from a distal end side toward a base end side of the second shaft member; and the hydraulic unit is configured such that the abutment portion of the first shaft member abuts against the lock side surface of the second shaft member when the parking locked state is established. In the parking device according to the present disclosure, when a hydraulic pressure that resists against the elastic force of the first elastic member is applied to the first shaft member when the second shaft member is not held on the first shaft member side by a magnetic force in the parking locked state, the first shaft member is moved toward the unlock side while moving the second shaft member away from the first shaft member through abutment between the abutment portion of the first shaft member and the distal end portion of the second shaft member, which establishes the parking unlocked state. In the parking device according to the present disclosure, when the parking locked state is established, the abutment portion of the first shaft member is in abutment with the lock side surface of the second shaft member. Thus, it is possible to reduce the amount of movement of the first shaft member toward the unlock side required to establish the parking unlocked state and to suppress a collision between the abutment portion of the first shaft member and the distal end portion of the second shaft member compared to a configuration in which such components are not in abutment with each other. If a state in which the second shaft member can be held on the first shaft member side by a magnetic force is (has been) established before a hydraulic pressure is reduced (e.g. before an engine-driven mechanical pump that generates the hydraulic pressure is stopped by idle stop) when the parking unlocked state is established by a hydraulic pressure, the first shaft member is held in position with the abutment portion of the first shaft member in abutment with the distal end portion of the second shaft member when a hydraulic pressure is reduced thereafter, although a force toward the lock side is applied to the first shaft member by the elastic force of the first elastic member. Consequently, the parking unlocked state can be held even when a hydraulic pressure is reduced after the parking unlocked state is established by a hydraulic pressure. When a hydraulic pressure is reduced when the second shaft member is not held on the first shaft member side by a magnetic force in the parking unlocked state, the first shaft member is moved toward the lock side by the elastic force of the first elastic member while moving the second shaft member away from the first shaft member through abutment between the abutment portion of the first shaft member and the distal end portion of the second shaft member, which establishes the parking locked state. Consequently, the parking locked state can be established more adequately when the second shaft member is not held on the first shaft member side by a magnetic force and a hydraulic pressure that resists against the elastic force of the first elastic member is not applied to the first shaft member. Originally, the hydraulic unit (in particular, the first shaft member) and the electromagnetic unit (in particular, the second shaft member) are disposed in directions that are orthogonal to each other. Thus, such components can be suitably disposed in a limited space compared to a configuration in which the two components are disposed in the direction of the same axis. In the thus configured parking device according to the present disclosure, the second shaft member of the electromagnetic unit may be moved away from the first shaft member when the parking locked state is established and the abutment portion of the first shaft member is in abutment with the lock side surface of the second shaft member compared to a time when the abutment portion of the first shaft member is not in abutment with the distal end portion of the second shaft member. In the parking device according to the present disclosure, in addition, the lock side surface of the second shaft member may be formed as a curved surface that is convex toward the lock side. With this configuration, a component, in the second direction, of the force applied from the first shaft member to the second shaft member is increased along with movement of the first shaft member toward the unlock side during movement of the first shaft member toward the unlock side due to a hydraulic pressure. Thus, the first shaft member can be moved toward the unlock side while smoothly moving the second shaft member away from the first shaft member. In the parking device according to such an aspect of the present disclosure, the abutment portion of the first shaft member may be formed in a cylindrical shape; and the lock side surface of the second shaft member may be formed as a curved surface with a radius of curvature that is smaller than a radius of curvature of the abutment portion of the first shaft member. With this configuration, the component discussed above tends to be increased more during movement of the first shaft member toward the unlock side due to a hydraulic pressure. Thus, the first shaft member can be moved toward the unlock side while smoothly moving the second shaft member away from the first shaft member even when the hydraulic pressure is more or less low. In the parking device according to the present disclosure, further, an unlock side surface of the distal end portion of the second shaft member on the unlock side may be formed to be inclined toward the unlock side from a distal end side toward a base end side of the second shaft member. With such a configuration, the second shaft member can be moved away from the first shaft member by a component, in the second direction, of the force applied from the first shaft member to the second shaft member when the abutment portion of the first shaft member and the unlock side surface of the second shaft member abut against each other during movement of the first shaft member toward the lock side. In the parking device according to the present disclosure, the magnetic force holding portion may be capable of holding the second shaft member on the first shaft member side using the magnetic force when a coil is energized; and the electromagnetic unit may be configured to allow the second shaft member to be moved away from the first shaft member, in the second direction, by a force applied from the abutment portion of the first shaft member to the distal end portion of the second shaft member during movement of the first shaft member when the coil is not energized. In this case, when the coil is energized, the second shaft member can be held on the first shaft member side by a magnetic force. Thus, when a hydraulic pressure is reduced when the coil is energized in the parking unlocked state, movement of the first shaft member toward the lock side is restricted through abutment between the abutment portion of the first shaft member and the distal end portion of the second shaft member. Consequently, the parking unlocked state can be held. In the parking device according to the present disclosure, moreover, the second shaft member is not moved (stroked) in the second direction by energizing the coil. Thus, the desired magnetic flux can be reduced compared to a configuration in which the second shaft member is moved in the second direction by energizing the coil. As a result, the number of turns of the coil required to obtain the desired magnetic flux can be reduced, which makes it possible to downsize the coil and hence the electromagnetic unit. When the coil is not energized, meanwhile, the second shaft member is allowed to be moved away from the first shaft member. Thus, when a hydraulic pressure is reduced when the coil is not energized in the parking unlocked state, the first shaft member is moved toward the lock side along with movement of the second shaft member away from the first shaft member through abutment between the abutment portion of the first shaft member and the distal end portion of the second shaft member, which establishes the parking locked state. Consequently, the parking locked state can be established more adequately when a hydraulic pressure that resists against the elastic force of the first elastic member is not applied to the first shaft member with the coil not energized (including an occasion in which the coil cannot be energized for some reason). In the parking device according to the present disclosure, the magnetic force holding portion may be a permanent magnet that holds the second shaft member on the first shaft member side using the magnetic force; and the electromagnetic unit may be configured to release holding of the second shaft member by the permanent magnet and allow the second shaft member to be moved away from the first shaft member, in the second direction, by a force applied from the abutment portion of the first shaft member to the distal end portion of the second shaft member during movement of the first shaft member when the coil is energized. In this case, when the coil is not energized, the second shaft member is held on the first shaft member side by the magnetic force of the permanent magnet. Thus, when a hydraulic pressure is reduced when the coil is not energized in the parking unlocked state, movement of the first shaft member toward the lock side is restricted through abutment between the abutment portion of the first shaft member and the distal end portion of the second shaft member. Consequently, the parking unlocked state can be held. When the coil is energized, meanwhile, the second shaft member is allowed to be moved away from the first shaft member. Thus, when a hydraulic pressure is reduced when the coil is energized in the parking unlocked state, the first shaft member is moved toward the lock side along with movement of the second shaft member away from the first shaft member through abutment between the abutment portion of the first shaft member and the distal end portion of the second shaft member, which establishes the parking locked state. Consequently, the parking locked state can be established more adequately. A modification of the present disclosure provides a parking device mounted on a vehicle to establish a parking locked state and a parking unlocked state, including: a first shaft member that is movable in a first direction by an elastic force of a first elastic member or a hydraulic pressure to switch between the parking locked state and the parking unlocked state; and a magnetic unit that includes a second shaft member that is advanceable and retractable in a second direction which is orthogonal to the first direction and that can restrict movement of the first shaft member through abutment between a distal end portion of the second shaft member and an abutment portion provided to the first shaft member, a second elastic member that urges the second shaft member toward the first shaft member in the second direction using an elastic force, a permanent magnet that locks the second shaft member using a magnetic force so as not to retract from the first shaft member, and an unlock portion that unlocks the second shaft member which has been locked by the permanent magnet along with energization of a coil, in which the magnetic unit is configured to allow the second shaft member to be retracted from the first shaft member by a force applied from the abutment portion of the first shaft member to the distal end portion of the second shaft member by the elastic force of the first elastic member or the hydraulic pressure when the coil is energized. In the parking device according to the modification of the present disclosure, the first shaft member and the second shaft member of the magnetic unit are disposed so as to move in directions that are orthogonal to each other. Thus, such components can be suitably disposed in a limited space compared to a configuration in which the two components are disposed (on the same axis) so as to be movable in the same direction. When the coil of the unlock portion of the magnetic unit is not energized, in addition, the second shaft member is locked by the magnetic force of the permanent magnet so as not to retract from the first shaft member. Consequently, movement of the first shaft member in the first direction is restricted when the abutment portion of the first shaft member and the distal end portion of the second shaft member abut against each other, which makes it possible to hold the parking locked state and the parking unlocked state. When the coil is energized, on the other hand, the second shaft member which has been locked by the permanent magnet is unlocked by the unlock portion, and the second shaft member is allowed to be retracted from the first shaft member by a force applied from the abutment portion of the first shaft member to the distal end portion of the second shaft member by the elastic force of the first elastic member or the hydraulic pressure. Consequently, the first shaft member is moved in the first direction by the elastic force of the first elastic member or the hydraulic pressure along with retraction of the second shaft member from the first shaft member, which makes it possible to switch between the parking locked state and the parking unlocked state. From what has been described above, it is not necessary to energize the coil in order to hold the parking locked state and the parking unlocked state, which makes it possible to suppress electric power consumption. In the thus configured parking device according to the modification of the present disclosure, the permanent magnet may be fixed to the second shaft member; the unlock portion may include a facing portion that is formed from a magnetic body and that faces the permanent magnet in the second direction; and the second shaft member may be locked by the attraction between the permanent magnet and the facing portion. In this case, it is considered that the permanent magnet can be fixed to the second shaft member easily and accurately by bonding or the like. In the parking device according to the modification of the present disclosure, in addition, the permanent magnet may be fixed to the unlock portion; the second shaft member may include a magnetic body portion formed from a magnetic body; the permanent magnet and the magnetic body portion may be disposed so as to face each other in the second direction; and the second shaft member may be locked by the attraction between the permanent magnet and the magnetic body portion. In the parking device according to the modification of the present disclosure in the aspect in which the permanent magnet is fixed to the second shaft member or the unlock portion, the second shaft member may include a shaft formed from a non-magnetic body and a plunger formed from a magnetic body; the shaft may include a small diameter portion that has the distal end portion and an expanded diameter portion that extends from the small diameter portion toward a side that is opposite to the abutment portion and that is larger in diameter than the small diameter portion; the plunger may be formed to be larger in diameter than the expanded diameter portion; the shaft and the plunger may be urged toward the first shaft member by the elastic force of the second elastic member such that an end surface of the plunger on a side of the first shaft member abuts against an end surface of the expanded diameter portion on a side that is opposite to a side of the small diameter portion, an end surface of the expanded diameter portion on the small diameter portion side abuts against a part of the unlock portion, and the distal end portion of the shaft can abut against the abutment portion of the first shaft member; and the permanent magnet may be disposed so as to surround an outer periphery of the expanded diameter portion. With this configuration, the shaft and the plunger are urged together toward the first shaft member by the elastic force of the second elastic member so that an end surface of the expanded diameter portion of the shaft on the small diameter portion side abuts against a part of the unlock portion. Thus, rattle of the shaft in the second direction can be suppressed. In addition, the permanent magnet is disposed so as to surround the outer periphery of the expanded diameter portion of the shaft. Thus, even if the shaft rattles in the radial direction, such rattle can be absorbed by the clearance between the outer peripheral surface of the expanded diameter portion and the inner peripheral surface of the permanent magnet. As a result, a magnetic gap formed at the outer periphery of the plunger can be reduced compared to a configuration in which the shaft, the plunger, and the permanent magnet are constituted integrally. In addition, the shaft is formed from a non-magnetic body. Thus, leakage of magnetic flux from the magnetic unit can be reduced. As a result, the magnetic efficiency can be enhanced while suppressing an increase in size of the magnetic unit. In the parking device according to the modification of the present disclosure in the aspect in which the permanent magnet is disposed so as to surround the outer periphery of the expanded diameter portion of the shaft, a length of the permanent magnet in the second direction may be smaller than a length of the expanded diameter portion in the second direction. With this configuration, in the case where the permanent magnet is fixed to the plunger, it is possible to suppress abutment (a collision) of the permanent magnet against a part (the facing portion which faces the permanent magnet in the second direction) of the unlock portion when the shaft and the plunger are moved toward the first shaft member, which protects the permanent magnet better. In the case where the permanent magnet is fixed to the unlock portion, meanwhile, it is possible to suppress abutment (a collision) of the permanent magnet against the plunger when the shaft and the plunger are moved toward the first shaft member, which protects the permanent magnet better. In the parking device according to the modification of the present disclosure, the distal end portion of the second shaft member may have an unlock side surface that receives a force from the abutment portion of the first shaft member during movement of the first shaft member toward a lock side, in the first direction, on which the parking locked state is established; and the unlock side surface may be formed to be inclined toward the unlock side from a distal end portion side toward a base end portion side of the second shaft member. With this configuration, the second shaft member can be retracted from the first shaft member by a component, in the second direction, of the force applied from the first shaft member to the second shaft member when the abutment portion of the first shaft member and the unlock side surface of the distal end portion of the second shaft member abut against each other during movement of the first shaft member toward the lock side. In the parking device according to the modification of the present disclosure, in addition, the distal end portion of the second shaft member may have a lock side surface that receives a force from the abutment portion of the first shaft member during movement of the first shaft member toward an unlock side, in the first direction, on which the parking unlocked state is established; and the lock side surface may be formed to be inclined toward the lock side from a distal end portion side toward a base end portion side of the second shaft member. With this configuration, the second shaft member can be retracted from the first shaft member by a component, in the second direction, of the force applied from the first shaft member to the second shaft member when the abutment portion of the first shaft member and the lock side surface of the distal end portion of the second shaft member abut against each other during movement of the first shaft member toward the unlock side. In the parking device according to the modification of the present disclosure, further, the abutment portion may be constituted as a roller that is rotatable with respect to the first shaft member. With this configuration, the frictional resistance between the abutment portion of the first shaft member and the distal end portion of the second shaft member can be reduced. In the parking device according to the modification of the present disclosure, additionally, the magnetic unit may include a bearing member that slidably supports the second shaft member. With this configuration, it is possible to make movement of the second shaft member in the second direction smoother. In the parking device according to the modification of the present disclosure, the first shaft member may be formed with a hole portion into which the distal end portion of the second shaft member is advanceable and which penetrates through the first shaft member; and the distal end portion of the second shaft member may be positioned in the hole portion. In the parking device according to the modification of the present disclosure, the magnetic unit may be configured such that when the coil is not energized, the second shaft member is not retracted from the first shaft member by a force applied from the abutment portion of the first shaft member to the distal end portion of the second shaft member by the elastic force of the first elastic member, but is allowed to be retracted from the first shaft member by a force applied from the abutment portion of the first shaft member to the distal end portion of the second shaft member by the elastic force of the first elastic member and a hydraulic pressure that resists against a force with which the permanent magnet locks the second shaft member. In the parking device according to the modification of the present disclosure, the first shaft member may be urged by the elastic force of the first elastic member toward a lock side, in the first direction, on which the parking lock is established, and moved by a hydraulic pressure that resists against the elastic force of the first elastic member toward an unlock side, in the first direction, on which the parking unlocked state is established. Part DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS: Now, a mode for carrying out the present disclosure will be described by way of preferred embodiments. FIG. 1 is a diagram illustrating a schematic configuration of a parking device 20 according to a first embodiment of the present disclosure in a parking locked state. FIG. 2 is a diagram illustrating a schematic configuration around a hole portion 36 formed in a piston rod 32 of the parking device 20. FIG. 3 is a diagram illustrating a schematic configuration of the parking device 20 according to the first embodiment in a parking unlocked state (with the parking unlocked state established by a hydraulic pressure). The parking device 20 according to the first embodiment is mounted on a vehicle. As illustrated in FIGS. 1 and 3, the parking device 20 includes: a parking gear 21 attached to a rotary shaft coupled to the side of an axle; a parking pawl 22 having a lug-like engagement portion that can mesh with the parking gear 21; a parking rod 24, to one end portion of which a cam member 23 is attached, the cam member 23 being abutting against the back surface of the lug-like engagement portion of the parking pawl 22 to turn the parking pawl 22; a turning member 25, one end portion of which is rotatably attached to the other end portion of the parking rod 24, the turning member 25 being turnable about a rotary shaft 26; a hydraulic unit 30 that applies a force to the other end portion of the turning member 25 through movement of the piston rod 32 which serves as a first shaft member in a first direction (up-down direction in the drawing) to turn the turning member 25; and an electromagnetic unit (magnetic unit) 50 that holds a solenoid shaft 52 that serves as a second shaft member that is movable in a second direction (left-right direction in the drawing) that is orthogonal to the first direction using a magnetic force when a coil 64 is energized to restrict movement of the piston rod 32 in the up-down direction in the drawing. In the parking device 20, as discussed in detail later, when the piston rod 32 is moved upward in the drawing from the parking locked state of FIG. 1, the turning member 25 is turned clockwise in the drawing to move the parking rod 24 rightward in the drawing, and the parking pawl 22 is moved upward in the drawing by the cam member 23 to be released from meshing with the parking gear 21, which establishes the parking unlocked state. When the piston rod 32 is moved downward in the drawing from the parking unlocked state of FIG. 3, meanwhile, the turning member 25 is turned counterclockwise in the drawing to move the parking rod 24 leftward in the drawing, and the parking pawl 22 is moved downward in the drawing by the cam member 23 to be brought into meshing with the parking gear 21, which establishes the parking locked state. Hereinafter, the lower side in the drawing and the upper side in the drawing are occasionally referred to as a “lock side” and an “unlock side”, respectively. The hydraulic unit 30 includes: the piston rod 32 which is movable in the up-down direction in the drawing and to which the other end portion of the turning member 25 is attached with a relatively large allowance by two pins 33 and 34; a piston 38 formed integrally with the piston rod 32; a case (cylinder) 40 which houses the piston 38 and in which a working oil inlet/discharge hole 41 for introducing working oil is formed; and a return spring 42 that serves as an elastic member disposed in the case 40 to urge the piston 38 downward in the drawing (toward the lock side) using an elastic force. In the hydraulic unit 30, the piston 38 (piston rod 32) is moved upward in the drawing (toward the unlock side) by a hydraulic pressure that resists against the elastic force of the return spring 42. As illustrated in FIGS. 1 to 3, the piston rod 32 is formed with the hole portion 36 (see in particular FIG. 2) which extends in the up-down direction in the drawing, and a pin 46 that extends across the hole portion 36 in the left-right direction in FIG. 2 (front-back direction in FIG. 1) is provided. The pin 46 includes a support shaft (shaft portion) 47 that is cylindrical in shape and that is fixed to the piston rod 32, and a roller 48 that serves as an abutment portion that is hollow and cylindrical in shape and that is rotatable with respect to the support shaft 47. As illustrated in FIG. 1, the roller 48 of the pin 46 of the piston rod 32 is in abutment with a lower abutment surface 56 of a distal end portion 54 of a solenoid shaft 52 (to be discussed in detail later). As illustrated in FIGS. 1 and 3, the electromagnetic unit 50 includes: the solenoid shaft 52 which is movable in the left-right direction in the drawing and which includes a small diameter portion 53 and a large diameter portion 57 that is larger in outside diameter than the small diameter portion 53; a yoke 60 that serves as a case that houses the large diameter portion 57 of the solenoid shaft 52; the coil 64 which is disposed on the inner peripheral side of the yoke 60; a core 66 disposed on the inner peripheral side of the coil 64 to support the large diameter portion 57 of the solenoid shaft 52 so as to be slidable in the left-right direction in the drawing; a bearing member (linear motion bearing) 68 fixed to the yoke 60 to support the small diameter portion 53 of the solenoid shaft 52 so as to be slidable in the left-right direction in the drawing; and a spring 70 disposed inside the yoke 60 to urge the solenoid shaft 52 toward the piston rod 32 (leftward in the drawing) using an elastic force. The spring load of the spring 70 is set to be smaller than the spring load of the return spring 42. In the electromagnetic unit 50, terminals from the coil 64 are disposed in a connector portion (not illustrated) formed on the outer peripheral side of the yoke 60, and the coil 64 is energized via the terminals. The yoke 60 is formed from a magnetic material, and includes an annular flange portion (projecting portion) 61 formed to project radially inward so as to have an inside diameter that is smaller than the inside diameter of the coil 64 and the outside diameter of the large diameter portion 57 of the solenoid shaft 52. A portion of the flange portion 61 on the radially inner side with respect to the inside diameter of the core 66 (a portion of the flange portion 61 that faces the large diameter portion 57 of the solenoid shaft 52 in the left-right direction in the drawing) attracts a magnetic body portion of the solenoid shaft 52 that is formed from a magnetic material through a magnetic force (formation of a magnetic circuit) when the coil 64 is energized, and thus will hereinafter be referred to as an “attracting portion 62”. The solenoid shaft 52 is disposed such that the distal end portion 54 (left end portion of the small diameter portion 53 in the drawing) of the solenoid shaft 52 faces about the right half, in the drawing, of the roller 48 of the pin 46 in the hole portion 36 of the piston rod 32 in the up-down direction in the drawing. A surface of the distal end portion 54 of the solenoid shaft 52 on the upper side in the drawing (unlock side) (a surface that abuts against the roller 48 to receive a force from the roller 48 during movement of the piston rod 32 toward the lower side in the drawing from the state of FIG. 3; hereinafter referred to as an “upper abutment surface 55”) is formed to be inclined upward in the drawing at a constant angle from the distal end side toward the base end side (from the left side toward the right side in the drawing). A surface of the distal end portion 54 of the solenoid shaft 52 on the lower side in the drawing (lock side) (a surface that abuts against the roller 48 to receive a force from the roller 48 during movement of the piston rod 32 toward the upper side in the drawing from the state of FIG. 1 or that state; hereinafter referred to as a “lower abutment surface 56”) is formed to be curved (arcuately curved as seen from the front side in the drawing) to be convex downward in the drawing from the distal end side toward the base end side with a radius of curvature that is smaller than the radius of curvature of the roller 48. In addition, the solenoid shaft 52 is formed from a non-magnetic material for the small diameter portion 53 and a part of the large diameter portion 57 on the radially inner side, and the remainder of the large diameter portion 57 is formed from a magnetic material (which corresponds to the magnetic body portion discussed above). A surface of the large diameter portion 57 of the solenoid shaft 52 on the left side in the drawing is pressed against a surface of the attracting portion 62 of the yoke 60 on the right side in the drawing by the elastic force of the spring 70 when the distal end portion 54 of the solenoid shaft 52 is not in abutment with the roller 48 of the pin 46 of the piston rod 32 and the coil 64 is not energized (when the parking unlocked state is established by a hydraulic pressure). In the parking locked state, meanwhile, as illustrated in FIG. 1, the pin 46 of the piston rod 32 abuts against the distal end portion 54 of the solenoid shaft 52, and the large diameter portion 57 is located away from the attracting portion 62 (has been moved rightward in the drawing with respect to the state of FIG. 3). Therefore, in the state of FIG. 1, the spring 70 has been contracted compared to the state of FIG. 3. The electromagnetic unit 50 is configured with the specifications of the coil 64 and the spring 70, the current for energizing the coil 64 (the magnitude of the attracting force of the attracting portion 62 of the yoke 60), and so forth adjusted such that when the coil 64 is energized, the solenoid shaft 52 is held on the left side in the drawing (on the piston rod 32 side) (movement of the solenoid shaft 52 toward the right side in the drawing (toward the side away from the piston rod 32) is restricted) with the attracting portion 62 of the yoke 60 attracting the large diameter portion 57 (in particular, the magnetic body portion) of the solenoid shaft 52 irrespective of whether or not a force is applied from the roller 48 of the pin 46 of the piston rod 32 to the distal end portion 54 (the upper abutment surface 55 or the lower abutment surface 56) of the solenoid shaft 52, and such that when the coil 64 is not energized, the solenoid shaft 52 is allowed to be moved rightward in the drawing by a force applied from the roller 48 of the piston rod 32 to the distal end portion 54 of the solenoid shaft 52 during movement of the piston rod 32. In the parking device 20 according to the first embodiment configured as described above, the hydraulic unit 30 (such as the piston rod 32) and the electromagnetic unit 50 (such as the solenoid shaft 52) are disposed in directions that are orthogonal to each other. Thus, such components can be suitably disposed in a limited space compared to a configuration in which the two components are disposed on the same axis. Now, operation of the parking device 20 according to the first embodiment configured as described above will be described. First, switching from the parking locked state in FIG. 1 to the parking unlocked state in FIG. 3 is considered. In the parking locked state, as discussed above, the roller 48 of the pin 46 of the piston rod 32 and the lower abutment surface 56 of the distal end portion 54 of the solenoid shaft 52 are in abutment with each other. In this state, the coil 64 is not energized. When a hydraulic pressure that resists against the elastic force of the return spring 42 is applied to the piston 38 (piston rod 32) in this state, a force directed obliquely rightward and upward in the drawing (specifically, directed from a location of abutment of the lower abutment surface 56 which is arcuately curved with the roller 48 toward the center of a circle having the arc as a part of the circumference) is applied from the piston rod 32 (roller 48) to the solenoid shaft 52, and the piston rod 32 is moved upward in the drawing (toward the unlock side) while moving the solenoid shaft 52 rightward in the drawing (toward the side away from the piston rod 32) using a component of the force in the left-right direction in the drawing. Then, after the piston rod 32 is moved to a position at which the rightmost portion, in the drawing, of the roller 48 of the piston rod 32 and the distal end (leftmost portion in the drawing) of the solenoid shaft 52 abut against each other as illustrated in FIG. 4, the piston rod 32 is moved upward in the drawing while the solenoid shaft 52 is returned leftward in the drawing (toward the piston rod 32) by the elastic force of the spring 70. Then, the piston rod 32 is moved to a position at which the roller 48 is not in contact with the distal end portion 54 of the solenoid shaft 52 as illustrated in FIG. 3. Switching to the parking unlocked state is performed in this way. In the first embodiment, in the parking locked state, the pin 46 of the piston rod 32 and the lower abutment surface 56 of the distal end portion 54 of the solenoid shaft 52 are in abutment with each other. Thus, it is possible to reduce the amount of movement of the piston rod 46 toward the upper side in FIG. 1 (unlock side) required to establish the parking unlocked state and to suppress a collision between the pin 46 and the lower abutment surface 56 compared to a configuration in which the two components are not in abutment with each other (the pin 46 is positioned slightly away on the lower side in FIG. 1 (lock side) from the lower abutment surface 56). In the parking locked state, in addition, the pin 46 of the piston rod 32 abuts against the distal end portion 54 of the solenoid shaft 52, and the large diameter portion 57 of the solenoid shaft 52 is located away from the attracting portion 62 of the yoke 60 (the solenoid shaft 52 has been moved rightward in FIG. 1 with respect to the state of FIG. 3). Thus, it is possible to reduce the amount of movement to be made before the piston rod 32 is moved upward in the drawing to reach the state of FIG. 4, and hence to reduce the amount of movement required to establish the parking unlocked state. In the first embodiment, in addition, the roller 48 which is rotatable with respect to the piston rod 32 (support shaft 47) is used as the abutment portion of the piston rod 32. Thus, the frictional resistance generated when the roller 48 of the piston rod 32 and the distal end portion 54 of the solenoid shaft 52 abut against each other can be reduced, which makes it possible to suppress wear of such components and to make movement of the piston rod 32 and the solenoid shaft 52 smoother. Further, the piston rod 32 is held by the bearing member 68. Thus, the sliding resistance of the solenoid shaft 52 can be reduced, which makes it possible to make movement of the solenoid shaft 52 smoother. Additionally, the lower abutment surface 56 is formed as a curved surface with a radius of curvature that is smaller than the radius of curvature of the roller 48. Thus, a force toward the right side in the drawing applied to the solenoid shaft 32 along with movement of the piston rod 32 toward the upper side in the drawing tends to be large. Thus, the piston rod 32 can be moved upward in the drawing while moving the solenoid shaft 52 rightward in the drawing even when the hydraulic pressure is more or less low. When the parking unlocked state is thus established by a hydraulic pressure, energization of the coil 64 is started before a hydraulic pressure for the piston 38 is reduced (e.g. before an engine-driven mechanical pump that generates the hydraulic pressure is stopped by idle stop). Consequently, the solenoid shaft 52 is held (movement of the solenoid shaft 52 is restricted) with a relatively large holding force with the attracting portion 62 attracting the large diameter portion 57 (in particular, the magnetic body portion) of the solenoid shaft 52. Thus, the piston rod 32 is held in position with the roller 48 of the pin 46 of the piston rod 32 in abutment with the upper abutment surface 55 of the distal end portion 54 of the solenoid shaft 52 as illustrated in FIG. 5 when a hydraulic pressure for the piston 38 is reduced thereafter (e.g. when idle stop is performed), although the piston rod 32 is moved downward in the drawing (toward the lock side) by the elastic force of the return spring 42. Consequently, the parking unlocked state can be held even when a hydraulic pressure for the piston 38 is reduced. In the electromagnetic unit 50 according to the first embodiment, moreover, the solenoid shaft 52 is attracted toward the attracting portion 62 to be held when the coil 64 is energized. Thus, the desired magnetic flux can be reduced compared to a configuration in which the solenoid shaft 52 is moved in the second direction (left-right direction in the drawing). As a result, the number of turns of the coil 64 required to obtain the desired magnetic flux can be reduced, which makes it possible to downsize the coil 64 and hence the
{'bibliographic_information': "{'country': 'US', 'doc-number': '14891766', 'kind': 'B2', 'date': '20140617', 'invention_title': 'Parking device'}", 'source_file': './grant/2017/ipg170711.xml', 'source_data': 'USPTO-Grant'}