JP2006224759A - Vehicle braking device and vehicle braking method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vehicle braking device and a vehicle braking method, capable of well suppressing the slipping down of a vehicle on an inclined road. <P>SOLUTION: The braking device 14 provided on the vehicle 1 comprises an actuator 20 capable of independently setting braking force to wheels FL to RR, wheel speed sensors 32 respectively provided on the wheels FL to RR, a parking gear of a transmission 4 for mechanically locking an output shaft 8 of the vehicle 1, and a linear sensor 36 converting the movement of a weight in a fore-and-aft direction of the vehicle 1 into an electric signal, and a brake ECU30. The ECU30 controls the actuator 20 to lock the output shaft 8 when the vehicle 1 is positioned on the inclined road, and add braking force to at least either one of the wheels FL to RR when one of the rear wheels RL and RR which are driving wheels rotates in an opposite direction to the other. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a vehicle braking device including an actuator capable of independently setting braking forces for a plurality of wheels provided in a vehicle, and a vehicle braking method using such an actuator.

Conventionally, as a technique for preventing a vehicle parked on a slope such as a slope from sliding down, a vehicle parked on a slope such as a slope even though the parking brake is operating. It is known that the fluid pressure increasing mechanism is controlled to increase the brake operating fluid pressure when the movement start is detected (see, for example, Patent Document 1). Also, in recent years, as a new type of parking brake unit, when the vehicle has stopped, the hydraulic brake unit functions as a parking brake by increasing and maintaining the brake pressure for all wheels, and a stage after a predetermined time has elapsed. A technique for releasing the braking force on all the wheels and operating a normal parking brake unit has also been proposed.
Japanese Patent Laid-Open No. 9-198880

  However, it is assumed that the parking brake is not activated when the vehicle is stopped on an inclined road such as a slope, and in such a case, the vehicle may slide down. Further, in the new type parking brake unit as described above, the braking force is applied to all the wheels from the hydraulic brake unit to the state where the braking force is applied to the predetermined two wheels by the normal parking brake unit. When shifting, the number of braked wheels may change, which may cause the vehicle parked on a slope such as a slope to slide down. Therefore, in these cases, it is necessary to prevent the vehicle from sliding down.

  Therefore, an object of the present invention is to provide a vehicle braking device and a vehicle braking method that can satisfactorily suppress a vehicle slippage on an inclined road.

  A vehicle braking device according to the present invention is provided for each of a plurality of wheels in a vehicle braking device including an actuator capable of independently setting a braking force for a plurality of wheels provided in the vehicle, and each of the corresponding wheels rotates. The rotation detection means for detecting the direction, the drive system lock means for mechanically locking the drive system of the vehicle, the ramp judgment means for judging whether or not the vehicle is located on the ramp, and the ramp judgment means Is determined to be located on the ramp and the drive system is locked by the drive system locking means, and one of the drive wheels of the wheels is rotating in the opposite direction to the other, And control means for controlling the actuator so that braking force is applied to at least one of the wheels.

  In general, if the slope of the ramp on which the vehicle is stopped is small, the vehicle can be stopped on the ramp by mechanically locking the drive system of the vehicle with drive system locking means. . However, even if the drive system is mechanically locked, since there is generally a differential gear between the left and right drive wheels, the slope of the ramp is large and the drive wheels are in contact with each other. When the friction coefficient of the road surface is different between right and left, there is a possibility that one of the driving wheels rotates in the opposite direction with respect to the other and the vehicle slips down.

  For this reason, in a vehicle to which this vehicle braking device is applied, the vehicle is located on the slope, the drive system is locked by the drive system locking means, and one of the drive wheels rotates in the opposite direction to the other. In this case, a braking force is applied to at least one of the wheels by the actuator. As a result, even after the vehicle is stopped on an inclined road having a relatively large degree of inclination, even if the driving system is locked by the driving system locking means and the parking brake unit is not operated, the vehicle is lowered on the inclined road. It becomes possible to suppress well. Here, “the state where one of the drive wheels is rotating in the opposite direction to the other” includes “the state where only one of the drive wheels is rotating” depending on the configuration of the drive system locking means. May be.

  In this case, the control means determines that the vehicle is located on the slope by the slope judgment means, the drive system is locked by the drive system lock means, and the rolling wheels of the wheels are in the downward direction. When one of the driving wheels rotates in the opposite direction to the other, a braking force is applied to the driving wheel rotating in the upward direction and no braking force is applied. It is preferable to control the actuator so that the speed becomes zero.

  In this way, when one of the drive wheels rotates in the opposite direction to the other and the vehicle is starting to slide down, a braking force is applied to the wheel rotating in the upward direction while generating friction with the road surface. By giving, it becomes possible to prevent the vehicle from sliding down.

  The control means determines that the vehicle is located on the slope by the slope judgment means, the drive system is locked by the drive system lock means, and the rolling wheels of the wheels are in the downward direction. When one of the driving wheels rotates in the direction opposite to the other, the braking force is applied to a part of the wheel rotating in the downward direction and the braking force is not applied. The actuator may be controlled so that the wheel speed becomes zero.

  Even if such a configuration is adopted, it is possible to suppress slipping of the vehicle by suppressing slipping of all the wheels.

  Further, the control means determines that the vehicle is positioned on the slope by the slope judgment means, the drive system is locked by the drive system lock means, and the rolling wheels of the wheels are in the downward direction. When one of the drive wheels rotates in the opposite direction to the other, the actuator is set so that braking force is applied to all of the wheels and the wheel speed is generated for any one of the wheels. It may be controlled.

  In this way, when the vehicle is starting to slide down, all the wheels slip even if braking force is applied to all of the wheels and the actuator is controlled so that the wheel speed is generated for any one of the wheels. Therefore, it is possible to satisfactorily prevent the vehicle from sliding down.

  The drive system locking means preferably includes means for locking the parking gear or the propeller shaft of the automatic transmission or continuously variable transmission.

  Another vehicle braking device according to the present invention is provided for each wheel in a vehicle braking device including an actuator capable of independently setting a braking force for a plurality of wheels provided in the vehicle, and each corresponding wheel rotation. Rotation detecting means for detecting the direction, parking brake unit for braking any of the plurality of wheels, slope judging means for judging whether or not the vehicle is located on the slope, and a plurality of wheels when the vehicle is stopped. And a control means for operating the parking brake unit by releasing the braking force on all wheels after controlling the actuator so that the braking force is applied to all of the wheels. It is determined that the vehicle is positioned on the road, and the actuator is released from the state in which braking force is applied to all of the plurality of wheels. The actuator is controlled so that braking force is applied to at least one of the wheels when the king brake unit is operated and a wheel not braked by the parking brake unit is rotating in the downward direction. And

  In this vehicle braking device, when the vehicle is stopped, the actuator is controlled by the control means so that the braking force is applied to all the wheels, and when a predetermined time elapses, the braking force for all the wheels is released. Thus, the actuator is controlled, and the parking brake unit is operated without the driver's operation. In this case, when the braking force is applied to all the wheels by the actuator and the braking force is applied to the predetermined wheel by the parking brake unit, the number of braked wheels is changed from 4 wheels to 2 wheels, for example. Decrease. Therefore, when the slope of the slope is large, when a normal parking brake unit is operated, the wheels that are not braked by the parking brake unit rotate in the downward direction, and the vehicle may slide down. There is.

  For this reason, in the vehicle to which the vehicle braking device is applied, the vehicle is located on the ramp, the state in which the braking force is applied to all of the plurality of wheels by the actuator is released, the parking brake unit is operated, and When a wheel that is not braked by the parking brake unit is rotating in the downward direction, a braking force is applied to at least one of the wheels by the actuator. As a result, even when the vehicle is stopped on an inclined road having a relatively large degree of inclination, even if the parking brake unit is activated by releasing the braking force applied to all of the plurality of wheels by the actuator, It is possible to satisfactorily suppress the vehicle sliding down.

  In this case, the control means determines that the vehicle is positioned on the slope by the slope judgment means, and releases the state in which the braking force is applied to all of the plurality of wheels by the actuator, so that the parking brake unit is When a wheel that is actuated and not braked by the parking brake unit is rotating in the downward direction, a braking force is applied to a part of the wheel that is rotating in the downward direction, and no braking force is applied. It is preferable to control the actuator so that the wheel speed of the wheel becomes zero.

  Under such a configuration, since the actuator is controlled so that the wheel speed is generated for any one of the wheels, it is possible to prevent the vehicle from sliding down by suppressing the slipping of all the wheels. Is possible.

  Further, the control means determines that the vehicle is located on the slope by the slope judgment means, and releases the state in which the braking force is applied to all of the plurality of wheels by the actuator and operates the parking brake unit. In addition, when the wheels that are not braked by the parking brake unit are rotating in the downward direction, the braking force is applied to all the wheels that are rotating in the downward direction, and the wheel is applied to any one of the wheels. The actuator may be controlled so that the speed is generated.

  Even if such a configuration is adopted, it is possible to suppress slipping of the vehicle by suppressing slipping of all the wheels.

  The vehicle braking method according to the present invention is a vehicle braking method using an actuator capable of independently setting braking forces for a plurality of wheels provided in the vehicle, wherein the vehicle is positioned on a ramp and the drive system of the vehicle is mechanical. And the actuator is controlled so that braking force is applied to at least one of the wheels when one of the wheels is rotating in the opposite direction to the other. Features.

  Another vehicle braking method according to the present invention is a vehicle braking method using an actuator capable of independently setting a braking force applied to a plurality of wheels provided in the vehicle. When the parking brake unit is operated from a state where the braking force is applied to all of the actuators and the wheel not braked by the parking brake unit is rotating in the downward direction, the braking force is applied to at least one of the wheels. The actuator is controlled so that is given.

  According to the present invention, it is possible to realize a vehicle braking device and a vehicle braking method that can satisfactorily suppress vehicle slippage on an inclined road.

  Hereinafter, the best mode for carrying out the present invention will be described in detail with reference to the drawings.

[First Embodiment]
FIG. 1 is a schematic diagram showing a vehicle equipped with a vehicle braking device according to the present invention. The vehicle 1 shown in the figure has wheels FL, FR, RL, and RR. Here, the wheel FL is the front left side, the wheel FR is the front right side, the wheel RL is the rear left side, and the wheel RR is the rear right wheel as viewed from the driver's seat. The vehicle 1 includes an internal combustion engine 2 that is a gasoline engine or a diesel engine, and a transaxle 6 that includes a transmission 4 that is an automatic transmission or a continuously variable transmission. The vehicle 1 of the present embodiment is configured as a so-called rear wheel drive vehicle, and an output shaft 8 constituting a drive system of the vehicle 1 is connected to a transmission 4 included in the transaxle 6. The output shaft 8 extends rearward from the transaxle 6 and is connected to a differential 10 including a differential gear. The differential 10 is connected to the rear wheels RL and RR via drive shafts 12L and 12R. Are connected. In addition, it cannot be overemphasized that the vehicle 1 of this embodiment can be comprised as what is called a hybrid vehicle and an electric vehicle.

  The vehicle 1 also includes a braking device 14 including disc brake units 16FL, 16FR, 16RL, and 16RR provided for each of the wheels FR to RL. Each of the disc brake units 16FR to RR includes a brake disc 17 and a brake caliper 18, and each brake caliper 18 incorporates a wheel cylinder (not shown). The wheel cylinders of each brake caliper 18 are connected to the actuator 20 via independent hydraulic lines. The actuator 20 is connected to two output ports of the master cylinder 22, and a brake pedal 26 is connected to the master cylinder 22 via a booster 24. In the present embodiment, the brake pressure of the wheel cylinder included in each brake caliper 18 can be set independently regardless of the hydraulic pressure supplied from the master cylinder 22.

  FIG. 2 is a system diagram of the actuator 20 included in the braking device 14. As shown in the figure, the hydraulic circuit of the actuator 20 is configured as a front and rear piping system in which a system for front wheels FL and FR and a system for rear wheels RL and RR are independent. Thereby, even if some trouble is caused in one system, the function of the other system is reliably maintained. The actuator 20 includes M / C cut solenoid valves F1 and R1, holding solenoid valves F11, F12, R11 and R12, pressure reducing solenoid valves F13, F14, R13 and R14, pumps F15 and R15, and reservoirs F16 and R16. . The pumps F15 and R15 are driven by a single motor (not shown).

  As shown in FIG. 2, the front wheel FL and the FR M / C cut solenoid valve F <b> 1 are connected to one output port of the master cylinder 22. Normally open holding solenoid valves F11 and F12 are connected in parallel to the M / C cut solenoid valve F1. A wheel cylinder of the disc brake unit 16FL is connected to the holding solenoid valve F11 via a hydraulic pressure line, and a wheel cylinder of the disc brake unit 16FR is connected to the holding solenoid valve F12 via a hydraulic pressure line. A discharge port of the pump F15 is connected between the M / C cut solenoid valve F1 and the holding solenoid valves F11 and F12. Furthermore, the hydraulic pressure line connecting the disc brake unit 16FL and the holding solenoid valve F11 is connected via the normally closed pressure reducing solenoid valve F13, and the hydraulic pressure line connecting the disc brake unit 16FR and the holding solenoid valve F12 is normal. Each is connected to a reservoir F16 via a closed pressure reducing solenoid valve F14.

  On the other hand, the rear wheel RL and the M / C cut solenoid valve R1 for RR are connected to the other output port of the master cylinder 22. Normally open holding solenoid valves R11 and R12 are connected in parallel to the M / C cut solenoid valve R1. A wheel cylinder of the disc brake unit 16RL is connected to the holding solenoid valve R11 via a hydraulic pressure line, and a wheel cylinder of the disc brake unit 16RR is connected to the holding solenoid valve R12 via a hydraulic pressure line. A discharge port of the pump R15 is connected between the M / C cut solenoid valve R1 and the holding solenoid valves R11 and R12. Furthermore, the hydraulic pressure line connecting the disc brake unit 16RL and the holding solenoid valve R11 is connected via the normally closed pressure reducing solenoid valve R13, and the hydraulic pressure line connecting the disc brake unit 16RR and the holding solenoid valve R12 is normal. Each is connected to a reservoir R16 via a closed pressure reducing solenoid valve R14. In the present embodiment, a master cylinder pressure sensor 19 is connected between the master cylinder 22 and the M / C cut solenoid valve R1.

  According to the actuator 20 configured as described above, by controlling the energization state of the holding solenoid valves F11, F12, R11 and R12 and the pressure reducing solenoid valves F13, F14, R13 and R14, the disc brake units 16FL to 16RR are controlled. It becomes possible to increase, reduce or maintain the brake pressure individually. That is, when the holding solenoid valves F11 to R12 and the pressure reducing solenoid valves F13 to R14 are not energized, the brake fluid is supplied from the master cylinder 22 or the pump F15 or R15 to the wheel cylinders of the disc brake units 16FL to 16RR. The brake pressure of units 16FL to 16RR is increased.

  Further, when the holding solenoid valves F11 to R12 and the pressure reducing solenoid valves F13 to R14 are energized, the wheel cylinders of the disc brake units 16FL to 16RR communicate with the reservoir F16 or R16, whereby the brake pressures of the disc brake units 16FL to 16RR are Depressurized. Further, when the holding solenoid valves F11 to R12 are energized, while the depressurizing solenoid valves F13 to R14 are de-energized, the brake pressures of the disc brake units 16FL to 16RR are held. The brake pressure of the disc brake units 16FL to 16RR can be gradually increased (pulse increase) by adjusting the energization / non-energization time interval. In addition, in the braking device 14, if the M / C cut solenoid valves F1 and R1 are energized and closed, the brake fluid in the reservoirs F16 and R16 is boosted by the pumps F15 and R15 to the disc brake units 16FL to 16RR. By supplying, regardless of the operation amount of the brake pedal 26, it is possible to apply a braking force greater than the force corresponding to the driver's pedal operation amount to the wheels FL to RR.

  The actuator 20 configured as described above is controlled by a brake electronic control unit (hereinafter referred to as “brake ECU”) 30 as shown in FIG. The brake ECU 30 includes a CPU, a ROM, a RAM, an input / output interface, a storage device, and the like (not shown). The brake ECU 30 includes M / C cut solenoid valves F1 and R1, a holding solenoid valves F11 to R12, and a pressure reducing solenoid valve included in the actuator 20. Motors for driving F13 to R14 and pumps F15 and R15 are controlled by the brake ECU 30. The master cylinder pressure sensor 19 described above is also connected to the brake ECU 30.

  Furthermore, a wheel speed sensor 32 provided for each of the wheels FR to RL is connected to the brake ECU 30, and each wheel speed sensor 32 has a rotation speed of the corresponding wheel FL to RR, that is, a wheel speed and a rotation direction. Is given to the brake ECU 30. Further, a stop lamp switch 34 and a linear G sensor 36 are connected to the brake ECU 30. The stop lamp switch 34 is turned on when the brake pedal 26 is depressed by the driver, and gives a signal to that effect to the brake ECU 30. The linear G sensor 36 converts the movement of the weight in the front-rear direction of the vehicle into an electric signal, and gives a signal that is linearly proportional to the acceleration (including deceleration) of the vehicle to the brake ECU 30.

  In addition, a shift unit 38 of the transmission 4 is connected to the brake ECU 30. The shift unit 38 automatically or continuously changes the speed of the transmission 4 according to the stopped state (parking: P), the reverse state (reverse: R), the neutral state (neutral: N), and the traveling state of the vehicle. The brake ECU 30 is operated by the user in order to set the automatic forward state (drive: D) to be set, and gives a signal indicating the shift range to the brake ECU 30. When the shift range of the shift unit 38 is set to “parking”, a parking gear (not shown) included in the transmission 4 is engaged with the output shaft 8, thereby the output constituting the drive system of the vehicle 1. The shaft 8 is mechanically locked. When the shift range of the shift unit 38 is set to “parking”, the propeller shaft may be mechanically locked instead of the output shaft.

  Further, the braking device 14 includes a parking brake unit 40 for braking the rear wheels RL and RR that are drive wheels. In the present embodiment, a so-called electric parking brake is employed as the parking brake unit 40, and an electric motor (not shown) for operating the parking brake unit 40 is also controlled by the brake ECU 30. A PB switch 42 for operating the parking brake unit 40 is also connected to the brake ECU 30. When the PB switch 42 is operated, the brake ECU 30 activates the electric motor, whereby the parking brake unit 40 brakes the rear wheels RL and RR. The parking brake unit 40 may be a manual or foot-operated type.

  Now, it is assumed that the parking brake unit 40 is not operated by the driver after the vehicle 1 is stopped on an inclined road such as a slope and the shift range is set to “parking”. There is also a risk that the vehicle 1 will slide down. For this reason, in the braking device 14 of the present embodiment, a routine shown in FIG. 3 is executed by the brake ECU 30 in order to suppress the sliding of the vehicle 1 in such a case.

  As shown in FIG. 3, the brake ECU 30 determines whether or not the vehicle 1 is stopped on the slope based on a signal from the linear G sensor 36 when the ignition switch is turned on ( S10). The brake ECU 30 repeats this determination process until it is determined that the vehicle 1 is stopped on the slope (No in S10). If the brake ECU 30 determines that the vehicle 1 is stopped on the slope (Yes in S10), then, It is determined whether or not the shift range of the shift unit 38 is set to “parking” (S12). If the brake ECU 30 determines that the shift range is not set to “parking” (No in S12), the brake ECU 30 determines again whether or not the vehicle 1 is stopped on the slope in S10.

  When it is determined that the shift range is set to “parking” (Yes in S12), the brake ECU 30 determines whether or not the PB switch 42 is turned on, that is, whether or not the parking brake unit 40 is operated ( S14). If it is determined that the PB switch 42 is turned on and the parking brake unit 40 has been operated (Yes in S14), the brake ECU 30 regards the possibility that the vehicle 1 will slide down as low as possible, and once ends this routine.

  On the other hand, the parking brake unit 40 is operated regardless of whether the vehicle 1 is stopped on the slope (Yes in S10) and the shift range is set to “parking” (Yes in S12). If not (No in S14), the vehicle 1 may slip down as described above. That is, when the shift range is set to “parking”, the parking gear included in the transmission 4 and the output shaft 8 are engaged with each other, and basically the rear wheels RL and RR that are drive wheels are mechanically engaged. However, a differential device 10 is provided between the rear wheel RL and the rear wheel RR to give a rotational difference therebetween. In this case, if the slope of the slope is small, the vehicle 1 can be stopped on the slope by mechanically locking the output shaft 8 of the vehicle 1 with the parking gear, but the slope of the slope is large. In addition, when the friction coefficient of the road surface in contact with the rear wheels RL and RR which are driving wheels is different on the left and right, the rear wheel RL and the rear wheel RR rotate in opposite directions, so that the vehicle 1 moves on the slope. There is a possibility of causing a situation of sliding down.

  In view of these points, if the brake ECU 30 makes a negative determination in S14, based on the signal from each wheel speed sensor 32, whether or not the vehicle 1 has slipped, that is, It is determined whether the front wheels FL and FR, which are driving wheels, rotate in the downward direction of the slope, and the rear wheel RL and the rear wheel RR, which are drive wheels, rotate in directions opposite to each other (S16). When it is determined that the vehicle 1 has not slipped down (No in S16), the brake ECU 30 determines again whether the vehicle 1 is stopped on the slope in S10. On the other hand, if it is determined that front wheels FL and FR are rotating in the downward direction of the slope and that rear wheel RL and rear wheel RR are rotating in opposite directions (Yes in S16), brake ECU 30 causes wheels FL to A slide-down suppressing process (S18) for controlling the actuator 20 so that a braking force is applied to at least one of the RRs is started.

  FIG. 4 is a flowchart for explaining the slip-down suppressing process in S18. As shown in the figure, the brake ECU 30 first determines, based on the signals from the respective wheel speed sensors 32, the left and right rear wheels RL and RR in the opposite direction to the front wheels FL and FR and other rear wheels. That is, the rear wheel rotating in the upward direction is determined, and a command signal is given to the actuator 20 so that a predetermined amount of braking force is applied to the rear wheel (S100). Specifically, in S100, the brake ECU 30 energizes (closes) the rear wheel M / C cut solenoid valve R1, and then sets the holding solenoid valves R11, R12 and the pressure reducing solenoid valves R13, R14. In addition, the one corresponding to the rear wheel rotating in the upward direction is de-energized, and among the holding solenoid valves R11 and R12, only the one corresponding to the rear wheel rotating in the downward direction is energized. The rear wheel pump R15 is operated for a predetermined time. As a result, the brake fluid in the reservoir R16 is pressurized by the pump R15 and is supplied only to the wheel cylinder of the disc brake units 16RL and 16RR corresponding to the wheel rotating in the upward direction. A predetermined amount of braking force is applied to the rear wheel that is rotating in the forward direction.

  When the process of S100 is executed, the brake ECU 30 determines that the wheel speeds of the non-braking wheels, that is, the rear wheels and the front wheels FL and FR to which no braking force was applied in S100, are all based on the signal from the wheel speed sensor 32. It is determined whether or not it is zero (S102). If it is determined that the wheel speeds of all the non-braking wheels are not zero (No in S102), the brake ECU 30 executes the process of S100 and increases the braking force for the rear wheels rotating in the upward direction. On the other hand, if it is determined that the wheel speeds of all the non-braking wheels are zero (Yes in S102), the brake ECU 30 corresponds to the rear wheel rotating in the upward direction among the holding solenoid valves R11 and R12. After energizing the valve, the pressure-reducing solenoid valves R13 and R14 corresponding to the rear wheel rotating in the upward direction are de-energized, and the disc brake units 16RL and 16RR are rotated in the upward direction. The brake pressure corresponding to the wheel is maintained (S104).

  When the process of S104 is executed, the brake ECU 30 executes the determination process of S102 again, and when an affirmative determination is made in S102, after the disc brake units 16RL and 16RR rotate in the upward direction in S104. The brake pressure corresponding to the wheel is maintained. If a negative determination is made in S102, the processing of S100 is executed to increase the brake pressure of the disc brake units 16RL and 16RR corresponding to the rear wheel rotating in the upward direction.

  As described above, according to the braking device 14 of the present embodiment, the vehicle 1 is located on the slope, the output shaft 8 is locked by the parking gear, and one of the rear wheels RL and RR that are drive wheels. Is rotating in the opposite direction to the other, the actuator 20 also applies a braking force to the rear wheel rotating in the upward direction while generating friction with the road surface. As a result, the differential 10 The braking force is also applied to the rear wheels that are not slipping on the road surface. As a result, after the vehicle 1 is stopped on an inclined road having a relatively high degree of inclination, the vehicle 1 slides down on the slope even when the output brake 8 is locked by the parking gear and the parking brake unit 40 is not operated. Can be suppressed satisfactorily.

  As shown in FIG. 3, when the process of S18 is started, the brake ECU 30 determines whether or not the stop lamp switch 34 is turned on, that is, whether or not the brake pedal 26 is operated by the driver (S20). When it is determined that the brake pedal 26 has not been operated by the driver (No in S20), the brake ECU 30 continues the slip-down suppressing process (S18) in FIG. Further, when it is determined that the brake pedal 26 is operated by the driver (Yes in S20), the brake ECU 30 stops the slip-down suppressing process of FIG. 4 (S22) and temporarily ends this routine.

  In S100 of FIG. 4, based on the signal from each wheel speed sensor 32, among all the wheels FL to RR, the wheel rotating in the downward direction is discriminated and the wheel rotating in the downward direction. A command signal may be given to the actuator 20 so that a predetermined amount of braking force is applied to a part of the motor (with at least one wheel remaining). In this case, in S102, it is only necessary to determine whether or not the wheel speeds of the wheels rotating in the downward direction to which no braking force is applied are zero. If such a procedure is adopted, the wheel speed can be generated on at least one of the wheels. Therefore, after the vehicle 1 is stopped on an inclined road having a relatively large degree of inclination, the output shaft 8 is moved by the parking gear. Even if the parking brake unit 40 is not operated simply by being locked, it is possible to prevent the vehicle 1 from sliding down by suppressing the slipping of all the wheels.

  FIG. 5 is a flowchart for explaining another slip-down suppressing process that can be executed in S18 of FIG.

  Under the routine shown in FIG. 5, the brake ECU 30 first gives a command signal to the actuator 20 so that a predetermined amount of braking force is applied to all the wheels FL to FR (S110). Specifically, in S110, the brake ECU 30 sets all of the holding solenoid valves F11 to R12 and the pressure reducing solenoid valves F13 to R14 to the non-conductive state after the M / C cut solenoid valves F1 and R1 are energized (closed). Energization is performed, and the pumps F15 and R15 are operated for a predetermined time. As a result, the brake fluid in the reservoirs F16 and R16 is boosted by the pumps F15 and R15 and supplied to the wheel cylinders of the disc brake units 16FL to 16RR, whereby a predetermined amount of braking force is applied to all the wheels FL to FR. Is granted.

  When the process of S110 is executed, the brake ECU 30 determines whether the wheel speed of any three of the wheels FL to RR is zero based on the signal from the wheel speed sensor 32 (S112). If it is determined that the wheel speed of any of the three wheels is zero (Yes in S112), the brake ECU 30 energizes the holding solenoid valves F11 to R12 and deenergizes the pressure reducing solenoid valves F13 to R14, thereby disc brake. The brake pressure of the units 16FL to 16RR is held (S114). When the process of S114 is executed, the brake ECU 30 executes the determination process of S112 again.

  On the other hand, if it is determined that the wheel speed of any three wheels is not zero (No in S112), the brake ECU 30 determines whether the wheel speeds of all the wheels FL to RR are zero (S116). If it is determined that the wheel speeds of all the wheels FL to RR are not zero (No in S116), the brake ECU 30 increases the braking force for all the wheels FL to RR in S110. On the other hand, if it is determined that the wheel speeds of all the wheels FL to RR are zero (Yes in S116), the brake ECU 30 causes the actuator 20 to reduce the brake pressure for any one of the predetermined wheels. A command signal is given to (S118). In S118, the brake ECU 30 energizes the holding solenoid valves F11 to R12 and the pressure reducing solenoid valves F13 to R14 corresponding to one target wheel for a predetermined time, and then executes the determination process of S112 again.

  As described above, when the vehicle 1 is being lowered, the braking force is applied to all the wheels FL to RR, and the actuator 20 is controlled so that the wheel speed is generated for any one of the wheels. Good. As a result, it is possible to suppress slipping of the vehicle 1 by suppressing slipping of all the wheels.

[Second Embodiment]
Hereinafter, a second embodiment of the present invention will be described with reference to FIGS. Note that the same reference numerals are given to the same elements as those described in relation to the first embodiment described above, and redundant descriptions are omitted.

  FIG. 6 relates to the second embodiment of the present invention, and is a flowchart showing another routine executed to suppress the vehicle 1 from sliding down in the braking device 14 of FIG. In the routine of FIG. 6, when the vehicle 1 is stopped, the brake ECU 30 applies a braking force to all the wheels FL to RR so that each of the disc brake units 16FL to 16RR is substantially operated as a parking brake unit. When the actuator 20 is controlled as described above and a predetermined time elapses, the actuator 20 is controlled so that the braking force for all the wheels FL to RR is released, and the electric parking brake unit (electric) 40 is operated without the driver's operation. It is premised on a case that can be operated.

  Even under the routine of FIG. 6, the brake ECU 30 determines whether or not the vehicle 1 is stopped on the slope based on a signal from the linear G sensor 36 when the ignition switch is turned on. (S30). The brake ECU 30 repeats this determination process until it is determined that the vehicle 1 is stopped on the slope (No in S30). As described above, when the vehicle 1 is stopped on the slope, in the present embodiment, the actuator 20 is controlled by the brake ECU 30 so that the braking force is applied to all the wheels FL to RR, and then the predetermined time has elapsed. When the time has elapsed, the braking force is released to all the wheels FL to RR, and the parking brake unit 40 is operated. For this reason, if the brake ECU 30 determines that the vehicle 1 is stopped on the slope (Yes in S30), the brake ECU 30 then determines whether or not the parking brake unit 40 is operating (S32). If it is determined that the parking brake unit 40 is not operating (No in S32), the brake ECU 30 determines again whether or not the vehicle 1 is stopped on the slope in S30.

  Here, if the braking force is applied to all the wheels FL to RR by the actuator 20 and the braking force is applied to the rear wheels FL and FR by the parking brake unit 40, the number of braked wheels is four. Decrease from wheel to two. Accordingly, when the slope of the slope is large, when the parking brake unit 40 is operated, the front wheels FL and RR that are not braked by the parking brake unit 40 rotate in the downward direction of the slope, and the vehicle 1 slides down. May occur.

  Therefore, when it is determined that the parking brake unit 40 is operating (Yes in S32), the brake ECU 30 determines that the front wheels FL and FR that are not braked by the parking brake unit 40 are based on the signals from the wheel speed sensors 32. It is determined whether or not is rotating in the downward direction of the slope (S34). When it is determined that the front wheels FL and FR are not rotating in the downward direction (No in S34), the brake ECU 30 determines again whether or not the vehicle 1 is stopped on the slope in S30. On the other hand, when determining that the front wheels FL and FR are rotating in the downward direction (Yes in S34), the brake ECU 30 controls the actuator 20 so that braking force is applied to at least one of the wheels FL to RR. The sliding down suppression process (S36) is started.

  FIG. 7 is a flowchart for explaining the slip-down suppressing process in S36. As shown in the figure, the brake ECU 30 first applies the actuator 20 so that a predetermined amount of braking force is applied to one of the predetermined front wheels FL and FR rotating in the downward direction. A command signal is given to (S120). Specifically, in S120, the brake ECU 30 energizes (closes) the front wheel M / C cut solenoid valve F1, and then among the holding solenoid valves F11 and F12 and the pressure reducing solenoid valves F13 and F14, The target wheel corresponding to the front wheel rotating in the downward direction is de-energized, the non-target solenoid valve F11, F12 is energized, and the front wheel pump F15 is turned on for a predetermined time. Only operate.

  As a result, the brake fluid in the reservoir F16 is boosted by the pump F15, and is supplied only to the target wheel cylinder of the disc brake units 16FL and 16FR, so that it is applied to one of the front wheels rotating in the downward direction. A predetermined amount of braking force is applied. That is, by executing the process of S120, braking force is applied to the three wheels of one of the front wheels and the rear wheels RL and RR.

  When the process of S120 is executed, the brake ECU 30 determines whether the wheel speed of the non-braking wheel, that is, the front wheel to which the braking force is not applied in S100, is zero based on the signal from the wheel speed sensor 32. Determination is made (S122). If it is determined that the wheel speed of the front wheel that is a non-braking wheel is not zero (No in S122), the brake ECU 30 executes the process of S120 to increase the braking force for one of the front wheels that is rotating in the downward direction. Let If it is determined that the wheel speed of the front wheel which is a non-braking wheel is zero (Yes in S122), the brake ECU 30 applies one of the holding solenoid valves F11 and F12 to the front wheel rotating in the downward direction. While energizing the corresponding one, among the decompression solenoid valves F13 and F14, the one corresponding to one of the front wheels rotating in the downward direction is de-energized, and the brake of the target of the disc brake units 16FL and 16FR The pressure is maintained (S124).

  When the process of S124 is executed, the brake ECU 30 executes the determination process of S122 again, and when an affirmative determination is made in S122, one of the disc brake units 16FL and 16FR rotating in the downward direction in S124. The brake pressure corresponding to the front wheel is maintained. If a negative determination is made in S122, the process of S120 is executed to increase the brake pressure of the disc brake unit 16FL and 16FR corresponding to one of the front wheels rotating in the downward direction.

  7 is executed, the state in which the vehicle 1 is positioned on the slope and the braking force is applied to all the wheels FL to RR by the actuator 20 is released. When the parking brake unit 40 is activated and both front wheels FL and FR not braked by the parking brake unit 40 are rotating in the downward direction, the front wheel FL rotating in the downward direction by the actuator 20 and A braking force is applied to one of the FRs. As a result, the vehicle 1 is braked so that the wheel speed is generated for any one of the wheels, so that the slipping of the vehicle 1 can be satisfactorily prevented by preventing all the wheels FL to RR from slipping. It becomes possible.

  Also in the routine of FIG. 6, when the process of S36 is started, the brake ECU 30 determines whether or not the stop lamp switch 34 is turned on, that is, whether or not the brake pedal 26 is operated by the driver (S38). If it is determined that the brake pedal 26 has not been operated by the driver (No in S38), the brake ECU 30 continues the slip-down suppressing process (S36) in FIG. Further, when it is determined that the brake pedal 26 is operated by the driver (Yes in S38), the brake ECU 30 stops the slip-down suppressing process of FIG. 7 (S40), and temporarily terminates this routine.

  FIG. 8 is a flowchart for explaining another slip-down suppressing process that can be executed in S36 of FIG.

  Under the routine shown in FIG. 8, the brake ECU 30 first applies a predetermined amount of braking force to all the wheels rotating in the downward direction, that is, both the front wheels FL and FR. A command signal is given to the actuator 20 (S130). Specifically, in S130, the brake ECU 30 deenergizes the holding solenoid valves F11 and F12 and the pressure-reducing solenoid valves F13 and F14 after energizing (closing) the front-wheel M / C cut solenoid valve F1. Furthermore, the pump F15 is operated for a predetermined time. As a result, the brake fluid in the reservoir F16 is boosted by the pump F15 and supplied to the disc brake units 16FL and 16FR, whereby a predetermined amount of braking force is applied to both the front wheels FL and FR rotating in the downward direction. Is granted. That is, by executing the process of S130, the braking force is applied to all the wheels FL to RR.

  When the process of S130 is executed, the brake ECU 30 determines whether the wheel speed of any three of the wheels FL to RR is zero based on the signal from the wheel speed sensor 32 (S132). If it is determined that the wheel speed of any of the three wheels is zero (Yes in S132), the brake ECU 30 energizes the holding solenoid valves F11 and F12, and deenergizes the decompression solenoid valves F13 and F14. The brake pressures of the brake units 16RL and 16RR are held (S134). When the process of S134 is executed, the brake ECU 30 executes the determination process of S132 again.

  On the other hand, if it is determined that the wheel speed of any three wheels is not zero (No in S132), the brake ECU 30 determines whether the wheel speeds of all the wheels FL to RR are zero (S136). When it is determined that the wheel speeds of all the wheels FL to RR are not zero (No in S136), the brake ECU 30 increases the braking force for both the front wheels FL and FR rotating in the downward direction in S130. . On the other hand, if it is determined that the wheel speeds of all the wheels FL to RR are zero (Yes in S136), the brake ECU 30 causes the actuator 20 to reduce the brake pressure for one of the predetermined front wheels. To give a command signal (S138). In S138, the brake ECU 30 energizes the holding solenoid valve F11 or F12 and the pressure-reducing solenoid valve F13 or F14 corresponding to one target front wheel for a predetermined time, and then executes the determination process of S132 again.

  As described above, the vehicle 1 is located on the slope, the state in which the braking force is applied to all of the plurality of wheels FL to RR is released by the actuator 20, the parking brake unit 40 is operated, and the parking is performed. When both front wheels FL and RR that are not braked by the brake unit 40 are rotating in the downward direction, braking force is applied to all of the front wheels FL and FR that are rotating in the downward direction, The actuator 20 may be controlled so that the wheel speed is generated for the front wheel. As a result, it is possible to suppress slipping of the vehicle satisfactorily by preventing all wheels from slipping.

It is a schematic block diagram which shows the vehicle provided with the vehicle braking device by this invention. It is a systematic diagram of the actuator contained in the vehicle braking device of FIG. FIG. 3 is a flowchart related to the first embodiment of the present invention, showing a routine that is executed in the vehicle braking device of FIG. 1 in order to suppress vehicle slippage. It is a flowchart for demonstrating the slip-down suppression process in the routine of FIG. It is a flowchart for demonstrating the other sliding suppression process which can be applied to the routine of FIG. FIG. 6 is a flowchart related to the second embodiment of the present invention, showing another routine executed to suppress the vehicle from sliding down in the vehicle braking device of FIG. 1. It is a flowchart for demonstrating the slip-down suppression process in the routine of FIG. It is a flowchart for demonstrating the other sliding suppression process which can be applied to the routine of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Vehicle, 2 Internal combustion engine, 4 Transmission, 6 Transaxle, 8 Output shaft, 10 Differential, 12L, 12R Drive shaft, 14 Braking device, 16FL, 16FR, 16RL, 16RR Disc brake unit, 17 Brake disc, 18 Brake caliper, 19 Master cylinder pressure sensor, 20 Actuator, 22 Master cylinder, 24 Booster, 26 Brake pedal, 30 Brake ECU, 32 Wheel speed sensor, 34 Stop lamp switch, 36 Linear G sensor, 38 Shift unit, 40 Parking brake unit 42 PB switch, F1, R1 M / C cut solenoid valve, F11, F12, R11, R12 Holding solenoid valve, F13, F14, R13, R14 Noid valve, F15, R15 pump, F16, R16 reservoir, FL, FR, RL, RR wheels.

Claims (10)

In a vehicle braking device including an actuator capable of independently setting braking force for a plurality of wheels provided in a vehicle,
Rotation detection means provided for each of the plurality of wheels, each detecting a rotation direction of the corresponding wheel;
Drive system locking means for mechanically locking the drive system of the vehicle;
Ramp judging means for judging whether or not the vehicle is located on the ramp;
It is judged by the ramp judging means that the vehicle is located on the ramp, the drive system is locked by the drive system locking means, and one of the wheels is driven by the other A vehicle braking device comprising: control means for controlling the actuator so that braking force is applied to at least one of the wheels when rotating in a reverse direction.   The control means determines that the vehicle is located on the slope by the slope judgment means, the drive system is locked by the drive system lock means, and a rolling wheel of the wheels. Is rotated in the downward direction and one of the driving wheels is rotated in the opposite direction to the other, a braking force is applied to the driving wheel rotating in the upward direction, and the braking force is The vehicle braking device according to claim 1, wherein the actuator is controlled so that a wheel speed of a wheel that is not applied is zero.   The control means determines that the vehicle is located on the slope by the slope judgment means, the drive system is locked by the drive system lock means, and a rolling wheel of the wheels. When one of the drive wheels rotates in the direction opposite to the other, a braking force is applied to a part of the wheel rotating in the downward direction, and The vehicle braking device according to claim 1, wherein the actuator is controlled so that a wheel speed of a wheel to which no power is applied becomes zero.   The control means determines that the vehicle is located on the slope by the slope judgment means, the drive system is locked by the drive system lock means, and a rolling wheel of the wheels. Is rotated in the downward direction and one of the drive wheels is rotated in the opposite direction to the other, a braking force is applied to all of the plurality of wheels, and the wheel speed is set to any one of the wheels. The vehicle braking device according to claim 1, wherein the actuator is controlled to be generated.   5. The vehicle braking device according to claim 1, wherein the drive system lock means includes a parking gear of an automatic transmission or a continuously variable transmission. In a vehicle braking device including an actuator capable of independently setting braking force for a plurality of wheels provided in a vehicle,
Rotation detection means provided for each of the plurality of wheels, each detecting a rotation direction of the corresponding wheel;
A parking brake unit for braking any of the plurality of wheels;
Ramp judging means for judging whether or not the vehicle is located on the ramp;
Control means for operating the parking brake unit by releasing the braking force on all the wheels after controlling the actuator so that the braking force is applied to all of the plurality of wheels when the vehicle stops. The control means determines that the vehicle is located on the slope by the slope judging means, and releases the state in which braking force is applied to all of the plurality of wheels by the actuator, so that the parking brake Controlling the actuator so that a braking force is applied to at least one of the wheels when the unit is operated and a wheel not braked by the parking brake unit is rotating in the downward direction. A vehicle braking device.   The control means determines that the vehicle is located on the slope by the slope judgment means, and releases the state in which the braking force is applied to all of the plurality of wheels by the actuator. When the brake unit is actuated and a wheel not braked by the parking brake unit is rotating in the downward direction, a braking force is applied to a part of the wheel rotating in the downward direction and the braking force is applied. The vehicle braking device according to claim 6, wherein the actuator is controlled so that a wheel speed of a wheel to which no power is applied is zero.   The control means determines that the vehicle is located on the slope by the slope judgment means, and releases the state in which the braking force is applied to all of the plurality of wheels by the actuator. When the brake unit is operated and the wheels not braked by the parking brake unit are rotating in the downward direction, braking force is applied to all the wheels rotating in the downward direction, and either The vehicle braking device according to claim 6, wherein the actuator is controlled so that a wheel speed is generated for one wheel. In a vehicle braking method using an actuator capable of independently setting a braking force for a plurality of wheels provided in a vehicle,
When the vehicle is located on a ramp and the drive system of the vehicle is mechanically locked and one of the wheels is rotating in the opposite direction to the other, the wheel A vehicle braking method, wherein the actuator is controlled so that a braking force is applied to at least one of the above. In a vehicle braking method using an actuator capable of independently setting a braking force for a plurality of wheels provided in a vehicle,
The vehicle is located on an inclined road, the state in which braking force is applied to all of the plurality of wheels by the actuator is released, the parking brake unit is operated, and is not braked by the parking brake unit. A vehicle braking method, wherein the actuator is controlled so that a braking force is applied to at least one of the wheels when the wheels are rotating in a downward direction.

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