Title of Invention: Process and device for actuating a braking system during the starting of a motor vehicle
Abstract: A process and device for starting a motor vehicle having a braking system in which a brake force is at least partially supplied by at least brake energy storage devices. Prior to starting a motor vehicle, the vehicle is initially switched into a non-drivable state in which the vehicle is disabled from movement. A charging state of each brake energy storage device may be checked to ensure an adequate charging state. If the charging state of at least one of the brake energy storage devices is greater than or equal to a predetermined minimum charging state, the vehicle may be switched into a drivable state and, thus, operable by the driver.
Detailed Description: Part PAC: DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Part PAR: The particulars shown herein are by way of example and for purposes of illustrative discussion of the preferred embodiments of the present invention only and are presented in the cause of providing what is believed to be the most useful and readily understood description of the principles and conceptual aspects of the invention. In this regard, no attempt is made to show structural details of the invention in more detail than is necessary for the fundamental understanding of the invention, the description taken with the drawings making apparent to those skilled in the art how the invention may be embodied in practice.
Part PAR_2: FIG. 1 illustrates a schematic representation of a braking system for a motor vehicle in which energy, e.g., electrical energy, utilized for performing a braking procedure may be supplied from brake energy storage devices. A vehicle driver determines an amount of desired braking by exerting a foot force on a brake pedal 2.
Part PAR_3: A sensor 24 may be positioned to detect the path covered by brake pedal 2 upon the application of foot force. Sensor 24 may convert the detected path into an electrical signal corresponding to the driver's amount of desired braking. Sensor 24 may transmit a signal to control units 6 through respective lines 4. A respective control unit 6 may be associated with each of the front and rear axles of the vehicle to convert the sensor signal into a control signal to control the braking procedure. Control units 6 may transmit control signals to respective brake actuators 12 through lines 26.
Part PAR_4: Each brake actuator 12 may exert a brake application force, in accordance with the control signal from control unit 6, on a respective brake disk 14. The brake application force may be applied through an electrically driven brake application device, discussed below, which may produce a braking action at each of the wheels 16. Each brake actuator 12 may receive all, or at least a portion, of the electrical energy necessary to perform a braking operation from brake energy storage devices 8, e.g., brake batteries. Each axle of the vehicle may have a brake energy storage device 8 associated therewith to supply the brake actuator 12. Brake storage device 8 may be coupled to either or both brake actuators 12 associated with the respective axle of the vehicle. That is, brake energy storage device 8 may communicate directly with control units 6 through electrical lines 28 and, through lines 26 from control unit 6, to brake actuators 12. When only a portion of the electrical energy is supplied via the brake energy storage devices 8, the remaining portion may be supplied from the vehicle's wiring system 10, which may communicate with brake actuators 12 in a similar manner to the brake energy storage device 8.
Part PAR_5: Whether or not the braking energy for a braking operation is fully or partially supplied from brake energy storage devices 8, safe braking of the vehicle may only be possible when brake energy storage devices 8 are included. Accordingly, at least one of the brake energy storage devices 8 should have a sufficient minimum charging state to properly actuate brake actuators 12. Particularly, when starting the vehicle, the brake energy storage devices 8 should be tested to ensure that a sufficient charging state exists. That is, when the vehicle has not been run or operated for an extended period of time, partial discharging of the brake energy storage devices 8 may occur, resulting in an improper charging level for actuating brake actuators 12. Brake energy storage devices 8 may be coupled to charge state sensors 18, for checking the charging state. Charge state sensors 18 may transmit a result of charging state detection (or check) to a control device 20 via lines 30. Control device 20 may assess whether the charging state of at least one of the brake energy stores 8 has a sufficient magnitude or level to safely operate the braking system of the vehicle. If a sufficient level is detected, an immobilizer 22, activated by a signal from control device 20 prior to checking the charging state to switch the vehicle into a non-drivable state, may be "released" via another signal from control device 20. The vehicle is now in a drivable state and operable by the driver. Conversely, if an insufficient level is detected, control device 20 will not send a second signal to immobilizer 22 to release the vehicle. Thus, if the charging state is inadequate, then the vehicle will remain in the non-drivable state and, thus, be inoperable by the driver.
Part PAR_6: FIG. 2 illustrates an exemplary flow diagram of the process for starting a motor vehicle in accordance with the present invention. At step 201, the vehicle may be automatically switched into a non-drivable state, e.g., via actuation of an immobilizer. In accordance with the present invention, the actuation of the immobilizer may be automatically effected prior to the starting process, e.g., when the vehicle was previously turned off.
Part PAR_7: After it is determined that the vehicle is in a non-drivable state, a measurement of the charging state of the brake energy storage devices 8 may occur through the charge state sensors 18 at step 202. The result of the charging state measurement may be transmitted to control device 20. At step 203, the process, via control device 20, determines whether the measured charging state is greater than or equal to a predetermined minimum charging state that may be stored within a memory storage device in control device 20. Further, control device 20 may include a comparator device to carry out a comparison of the measured charging state to the predetermined value. When a positive result is found, i.e., at least one of the brake energy storage devices 8 is greater than or equal to the predetermined minimum charging state, the vehicle may be safely switched over to the drivable state. Accordingly, control device 20, at step 204, may transmit a signal to the immobilizer to effectuate a release. The process for safely starting the vehicle can be further enhanced by alternatively adjusting the process to include an additional step of transferring the vehicle into the drivable state only if each brake energy storage device 8 is found to meet or exceed the predetermined minimum charging state.
Part PAR_8: Conversely, when a negative result is found, i.e., the measured charging state of each brake energy storage device 8 is found to be lower than the predetermined minimum charging state, the brake energy storage devices 8 may be recharged at step 205. The recharging process can be carried out by either a vehicle-based generator or an external recharging device. The recharged charging state of the brake energy storage devices 8 may be measured at step 202. The result of the charging state measurement may be transmitted to control device 20 for comparison with the predetermined minimum charging state at step 203. A loop including steps 202, 203, and 205 may be repeated as necessary until the measured charging state of at least one brake energy storage device 8 enables a positive result from control device 20. Upon transmission of the positive result to immobilizer 22, the immobilizer may be released, thus, switching the vehicle into its drivable state.
Part PAR_9: FIGS. 3a and 3b illustrate an exemplary diagram of a drivable and non-drivable state, respectively. Immobilizer 22, e.g., an electrical parking brake, may be constructed to actuate the non-drivable state when in a non-current carrying state and to effectuate a release of the vehicle (into the drivable state) when in a current carrying state. FIG. 3 shows schematic representations of only the components sufficient for the purposes of explanation. The electrical parking brake may be integrated into brake actuator 12. Brake actuator 12 may also include an electromotor 32 for imparting rotational movement on a spindle nut 34 and for imparting axial movement on a spindle rod 58 engaged with spindle nut 34.
Part PAR_10: Rotational movement of spindle nut 34 may produce axial movement of spindle rod 58 to force brake piston 36 in a direction toward or away from brake disk 14. As a result, during a braking operation, brake linings 38, which may be operatively connected to piston 36, may likewise be imparted with axial movement in a direction toward or away from brake disk 14 through brake linings 38. In a brake actuation, i.e., towards brake disk 14, after traversing an air gap 52, brake linings 38 may abuttingly rest against brake disk 14 to produce a predetermined braking force. After the braking operation, brake linings 38, brake piston 36, the spindle rod 58 may be substantially returned to their initial positions by restoring forces.
Part PAR_11: In addition to the above-described components of the vehicle braking system, brake actuator 12 may also include an electrical parking brake (brake lock) 40 that may selectively lock disk brake 14. Electrical parking brake 45 may include, e.g., an electromagnetic friction slip coupling. Electromagnetic friction slip coupling may include, e.g., an electromagnet comprising a conductive coil 42 wound around a metal core 54 and may be located within a housing 44 of electrical parking brake 40. Electrical parking brake 40 may also include a metal pin 48, having a friction head 56, that may be supported to axially move within housing 44. Further, a compression spring 46 may be disposed between metal core 54 and metal pin 48 to bias metal core 54 and metal pin 48 away from each other.
Part PAR_12: FIG. 3a shows brake actuator 12 as a "released" parking brake, i.e., immobilizer 22 is disposed in its "released" (current carrying) state. The "released" state of electrical parking brake 40 may be effected by applying an electric voltage across conductive coil 42 to provide a current therethrough. In operation, if at least one of brake energy storage devices 8 has been shown, e.g., through the exemplary procedure shown in FIG. 2, to have a sufficient charging state when the vehicle is started, control device 20 may effectuate the application of electric voltage to brake actuators 12 to actuate the electromagnet.
Part PAR_13: When the electromagnet is actuated via current flow through conductive coil 42, metal pin 48 may be attracted toward the electromagnet and pulled into housing 44. The magnetic attraction of the conductive coil 42 to metal pin 48 is sufficient to overcome the spring force of spring 46. In the "released" state, electrical parking brake 40 does not hinder the rotational movement of spindle nut 34, thus, enabling the actuation or resetting of brake linings 38 and brake pistons 36.
Part PAR_14: FIG. 3b shows brake actuator 12 located in a locked state, i.e., the immobilizer 22 is in its active state. Preferably, the active state of immobilizer 22 may be automatically enabled when the vehicle is turned off.
Part PAR_15: In the "released" electrical parking brake, brake actuator 12 may be actuated until brake linings 38 abuttingly rest against brake disk 14. As discussed above, the actuation of brake actuator 12 may be carried out, for example, by control device 20 when the vehicle is shut off. While maintaining this state, electrical parking brake 40 may be switched over from the current carrying "released" state into the non-current carrying "locked" or "set" state. The braking system may also be located in the locked state by actuation of by control device 20 when the vehicle is shut off, i.e., while brake linings 38 are abuttingly resting against brake disk 14. The action of the electromagnet may then cancelled by control device 20, i.e., the voltage may be removed from conductive coil 42. Upon the cessation of the magnetic attraction between conductive coil 42 and metal pin 48, compression spring 46 may bias metal pin 48 (and friction head 56 ) outward, i.e., toward spindle nut 34. The outward biased force exerted on metal pin 48 against spindle nut 34 may produce a friction force that is greater than the restoring force of brake linings 38 or the spindle rod 58. Thus, the braking system will remain in the locked position until an outside force, e.g., via control device 20, releases the brakes.
Part PAR_16: Thus, brake linings 38 may be locked in their position even when electromotor 32 is not being driven and, consequently, brake linings 38 may also immobilize brake disks 14.
Part PAR_17: It is noted that the foregoing examples have been provided merely for the purpose of explanation and are in no way to be construed as limiting of the present invention. While the invention has been described with reference to a preferred embodiment, it is understood that the words which have been used herein are words of description and illustration, rather than words of limitation. Changes may be made, within the purview of the appended claims, as presently stated and as amended, without departing from the scope and spirit of the invention in its aspects. Although the invention has been described herein with reference to particular means, materials and embodiments, the invention is not intended to be limited to the particulars disclosed herein; rather, the invention extends to all functionally equivalent structures, methods and uses, such as are within the scope of the appended claims. For example, the present invention may utilize a higher or lower number of press gaps depending on the specific need.
Part PAC_2: Reference Numeral List
Part TBL: ______________________________________ 2 brake pedal 4 lines 6 control unit for brake actuators 8 brake energy storage device (battery) 10 wiring system 12 brake actuators 14 brake disk 16 wheel 18 charge state sensor 20 control device 22 immobilizer 24 sensor 26 lines 28 lines 30 lines 32 electromotor 34 spindle nut 36 brake piston 38 brake lining 40 electrical parking brake, e.g., an electrical metal friction slip coupling 42 conductive coil 44 housing of friction slip coupling 46 compression spring 48 metal pin 52 air gap 54 metal core 56 friction head 58 spindle rod ______________________________________


{'bibliographic_information': "{'Patent Number': '059575514', 'Series Code': '8', 'Application Number': '7969481', 'Application Type': '1', 'Art unit': '363', 'Application Filing Date': '19970207', 'Title of Invention': 'Process and device for actuating a braking system during the starting of a motor vehicle', 'Issue Date': '19990928', 'Number of Claims': '28', 'Exemplary Claim Number(s)': '1', 'Primary Examiner': 'Schwartz; Chris', 'Number of Drawing Sheets': '4', 'Number of figures': '4'}", 'source_file': './grant/1999/pftaps19990928_wk39.txt', 'source_data': 'USPTO-Grant'}