JP6807720B2 - Electric brake device - Google Patents

Description

The present invention relates to an electric braking device that applies a braking force to a vehicle such as an automobile.

As a disc brake provided in a vehicle, for example, not only a braking force is generated based on hydraulic pressure when the vehicle is running, but also a braking force is generated based on the drive (rotation) of an electric motor when the vehicle is stopped or parked. A hydraulic disc brake with an electric parking brake function is known (Patent Document 1). Here, in Patent Document 1, when the electric parking brake is applied (operated), it is reapplied (reclamped) after a lapse of a predetermined time from the application in consideration of a decrease in braking force due to heat shrinkage of the disc rotor and the brake pad. ) Techniques are described.

Japanese Unexamined Patent Publication No. 2016-89903

By the way, when the electric parking brake is applied, if the hydraulic pressure in the caliper cylinder (foil cylinder hydraulic pressure) is large, the reapply may be performed even if the reapply (restart) is not necessary. ..

An object of the present invention is to provide an electric braking device capable of limiting unnecessary reapplying.

In order to solve the above-mentioned problems, the electric brake device according to the present invention has a cylinder mechanism having a piston that moves by hydraulic pressure and presses the braking member against the braked member, and the electric brake moves the piston to move the braking member. the pressed against the braked member, an electric mechanism for holding the braking state, and controlling the operation of the electric motor, to complete the holding operation by the electric mechanism, after stopping the operation of the electric motor, the said braking member to be In an electric brake device including a control device that restarts the electric motor in a direction of pressing against a braking member, the control device has a hydraulic pressure on the piston at a predetermined value or more when the holding operation by the electric mechanism is completed. In this case, it is prohibited to restart the electric motor in the direction of pressing the braking member against the braked member.

The electric braking device according to the present invention can limit unnecessary reactivation (reapply).

The conceptual diagram of the vehicle equipped with the electric brake device by embodiment. FIG. 1 is an enlarged vertical sectional view showing a disc brake with an electric parking brake function provided on the rear wheel side in FIG. 1. The block diagram which shows the parking brake control device in FIG. 1 together with the rear wheel side disc brake and the like. The flow chart which shows the process by the parking brake control device in FIG. The flow chart which shows the reapply necessity determination process in FIG. The flow chart which shows the reapply start determination process in FIG. The characteristic diagram which shows an example of the time change of a hydraulic pressure Pa and a pressing pressure F. An example of the relationship between the temperature TMP and the pressing pressure F according to the first embodiment (upper left), an example of the relationship between the hydraulic pressure Pa at the completion of application and the pressing pressure F (upper right), and the restarting hydraulic pressure value Pm. The characteristic diagram which shows an example (lower right) of the relationship with the push pressure increase amount ΔF by a hydraulic pressure. FIG. 5 is a characteristic diagram showing an example of the relationship between the difference (ΔFt−ΔFp) between the pressing pressure decrease amount ΔFt due to heat shrinkage and the pressing pressure increase amount ΔFp due to hydraulic pressure and the target current value Am. An example of the relationship between the inclination G and the pressing force F according to the second embodiment (upper left), an example of the relationship between the hydraulic pressure Pa at the completion of application and the pressing force F (upper right), the restarting hydraulic pressure value Pm and the hydraulic pressure. FIG. 5 is a characteristic diagram showing an example of the relationship between the pressing force increase amount ΔF and the relationship between the inclination G and the target current value Am (lower left).

Hereinafter, a case where the electric brake device according to the embodiment is mounted on a four-wheeled vehicle will be described as an example, and will be described with reference to the accompanying drawings. Each step of the flow chart shown in FIGS. 4 to 6 uses the notation "S" (for example, step 1 = "S1").

1 to 9 show a first embodiment. In FIG. 1, on the lower side (road surface side) of the vehicle body 1 constituting the body of the vehicle, for example, a total of four front wheels 2 (FL, FR) and left and right rear wheels 3 (RL, RR) are formed. Wheels are provided. The wheels (2 front wheels and 3 rear wheels) form a vehicle together with the vehicle body 1. The vehicle is equipped with a braking system for applying braking force. The vehicle braking system will be described below.

The front wheels 2 and the rear wheels 3 are provided with a disc rotor 4 as a braked member (rotating member) that rotates together with the respective wheels (each front wheel 2 and each rear wheel 3). The disc rotor 4 for the front wheel 2 is subjected to braking force by the front wheel side disc brake 5, which is a hydraulic disc brake. The disc rotor 4 for the rear wheel 3 is provided with a braking force by the rear wheel side disc brake 6, which is a hydraulic disc brake with an electric parking brake function.

A pair (one set) of rear wheel side disc brakes 6 provided corresponding to the left and right rear wheels 3 constitutes a braking device (electric brake device) together with a parking brake control device 24 described later. As shown in FIG. 2, the rear wheel side disc brake 6 includes, for example, a mounting member 6A called a carrier, a caliper 6B as a wheel cylinder, and a pair of brake pads 6C as a braking member (friction member, friction pad). , The piston 6D as a pressing member is included. In this case, the caliper 6B and the piston 6D form a cylinder mechanism. The cylinder mechanism is a mechanism that moves by hydraulic pressure and presses the brake pad 6C against the disc rotor 4.

The mounting member 6A is fixed to the non-rotating portion of the vehicle and is formed so as to straddle the outer peripheral side of the disc rotor 4. The caliper 6B is provided on the mounting member 6A so that the disc rotor 4 can be moved in the axial direction. The caliper 6B includes a cylinder 6B1, a claw portion 6B2, a cylinder portion 6B3, and a bridge portion 6B4. The brake pad 6C is movably attached to the attachment member 6A and is arranged so as to be in contact with the disc rotor 4. The piston 6D presses the brake pad 6C against the disc rotor 4.

Here, the caliper 6B propels the brake pad 6C with the piston 6D by supplying (adding) the hydraulic pressure (brake hydraulic pressure) into the cylinder 6B1 based on the operation of the brake pedal 9 or the like. At this time, the brake pad 6C is pressed against both sides of the disc rotor 4 by the claw portion 6B2 of the caliper 6B and the piston 6D. As a result, braking force is applied to the rear wheels 3 that rotate together with the disc rotor 4.

Further, the rear wheel side disc brake 6 is provided with an electric actuator 7 and a pressing member holding mechanism 8. The electric actuator 7 includes an electric motor 7A as an electric motor, a deceleration mechanism (not shown) for decelerating the rotation of the electric motor 7A, and the like. The electric motor 7A serves as a drive source for propelling the piston 6D. The pressing member holding mechanism 8 constitutes a holding mechanism for holding the pressing force of the brake pad 6C. In this case, the pressing member holding mechanism 8 is configured to include a rotary linear motion member 8A that converts the rotation of the electric motor 7A into an axial displacement (linear displacement) of the piston 6D and propels the piston 6D. ..

That is, the pressing member holding mechanism 8 converts the rotation of the electric motor 7A into the axial displacement of the piston 6D, and holds the piston 6D propelled by the electric motor 7A. As a result, the pressing member holding mechanism 8 constitutes an electric mechanism together with the electric motor 7A. The electric mechanism operates the electric motor 7A in the direction of pressing the brake pad 6C against the disc rotor 4 to maintain the braking state. In other words, the pressing member holding mechanism 8 applies thrust to the piston 6D by the electric motor 7A, propels the brake pad 6C by the piston 6D, presses the disc rotor 4, and holds the thrust of the piston 6D. The pressing member holding mechanism 8 is configured as, for example, a rotation linear motion conversion mechanism such as a spindle nut mechanism.

The rear wheel side disc brake 6 propels the piston 6D by the brake fluid pressure generated based on the operation of the brake pedal 9, and presses the disc rotor 4 with the brake pad 6C to extend the wheels (rear wheel 3). Gives braking force to the vehicle. In addition to this, as will be described later, the rear wheel side disc brake 6 propels the piston 6D via the pressing member holding mechanism 8 by the electric motor 7A in response to an operation request based on a signal or the like from the parking brake switch 23. And apply braking force (parking brake or auxiliary brake) to the vehicle.

That is, the rear wheel side disc brake 6 constituting the electric brake device (electric parking brake mechanism) drives the electric motor 7A and propels the piston 6D by the rotary linear motion member 8A to make the brake pad 6C the disc rotor 4 Press and hold. In this case, the rear wheel side disc brake 6 propels the piston 6D with the electric motor 7A in response to the parking brake request signal (apply request signal), which is an apply request for applying the parking brake, to hold the braking of the vehicle. It is possible to do. At the same time, the rear wheel side disc brake 6 brakes the vehicle by supplying hydraulic pressure from a hydraulic pressure source (master cylinder 12 described later, if necessary, hydraulic pressure supply device 15) in response to the operation of the brake pedal 9. It is possible.

As described above, the rear wheel side disc brake 6 has a pressing member holding mechanism 8 that presses the brake pad 6C against the disc rotor 4 by the electric motor 7A and holds the pressing force of the brake pad 6C, and also has the electric motor 7A. The brake pad 6C can be pressed against the disc rotor 4 by a hydraulic pressure applied separately from the pressing by.

On the other hand, the pair (one set) of front wheel side disc brakes 5 provided corresponding to the left and right front wheels 2 have almost the same configuration as the rear wheel side disc brakes 6 except for the mechanism related to the operation of the parking brake. Has been done. That is, as shown in FIG. 1, the front wheel side disc brake 5 includes a mounting member (not shown), a caliper 5A, a brake pad (not shown), a piston 5B, and the like, but the parking brake is activated and released. The electric actuator 7 (electric motor 7A), the pressing member holding mechanism 8, and the like are not provided. However, the front wheel side disc brake 5 propels the piston 5B by the hydraulic pressure generated based on the operation of the brake pedal 9 or the like, and applies braking force to the wheels (front wheel 2) and the vehicle. This is the same as the disc brake 6.

The front wheel side disc brake 5 may be a disc brake with an electric parking brake function, similarly to the rear wheel side disc brake 6. Further, in the embodiment, a hydraulic disc brake 6 provided with an electric motor 7A is used as the electric brake device (parking brake device). However, the electric brake device is not limited to this, and for example, a disc brake equipped with an electric drum type parking brake, a cable puller type parking brake device that applies the parking brake by pulling a cable with an electric motor, and the like are used. You may. That is, the parking brake device presses (propulses) the friction member (pad, shoe) against the rotating member (rotor, drum) based on the drive of the electric motor (electric actuator), and holds and releases the pressing force. Various electric brake mechanisms (electric parking brake mechanisms) can be used as long as they can be configured.

A brake pedal 9 is provided on the front board side of the vehicle body 1. The brake pedal 9 is stepped on by the driver when the vehicle is braked, and based on this operation, the disc brakes 5 and 6 are applied and released with braking force as a normal brake (service brake). The brake pedal 9 is provided with a brake operation detection sensor (brake sensor) 10 such as a brake lamp switch, a pedal switch (brake switch), and a pedal stroke sensor.

The brake operation detection sensor 10 detects whether or not the brake pedal 9 is depressed or the amount of the operation, and outputs the detection signal to the ESC control device 17. The detection signal of the brake operation detection sensor 10 is transmitted, for example, via the vehicle data bus 20 or a communication line (not shown) connecting the ESC control device 17 and the parking brake control device 24 (parking brake control). Output to device 24).

The stepping operation of the brake pedal 9 is transmitted to the master cylinder 12 that functions as a hydraulic source (hydraulic pressure source) via the booster 11. The booster 11 is configured as a negative pressure booster (atmospheric pressure booster) or an electric booster (electric booster) provided between the brake pedal 9 and the master cylinder 12, and has a pedaling force when the brake pedal 9 is depressed. Is increased and transmitted to the master cylinder 12.

At this time, the master cylinder 12 generates hydraulic pressure by the brake fluid supplied (replenished) from the master reservoir 13. The master reservoir 13 serves as a hydraulic fluid tank in which the brake fluid is stored. The mechanism that generates hydraulic pressure by the brake pedal 9 is not limited to the above configuration, and may be a mechanism that generates hydraulic pressure in response to the operation of the brake pedal 9, for example, a brake-by-wire type mechanism. ..

The hydraulic pressure generated in the master cylinder 12 is sent to the hydraulic pressure supply device 15 (hereinafter referred to as ESC 15) via, for example, a pair of cylinder-side hydraulic pressure pipes 14A and 14B. The ESC 15 is arranged between the disc brakes 5 and 6 and the master cylinder 12. The ESC 15 distributes and supplies the hydraulic pressure output from the master cylinder 12 via the cylinder-side hydraulic pipes 14A and 14B to the disc brakes 5 and 6 via the brake-side piping portions 16A, 16B, 16C and 16D. .. That is, the ESC 15 applies the hydraulic pressure (brake hydraulic pressure) corresponding to the operation of the brake pedal 9 to the disc brakes 5, 6 (calipers 5A, 6B) provided on each wheel (front wheel 2, each rear wheel 3). It is for supplying. As a result, braking force can be applied to each of the wheels (each front wheel 2 and each rear wheel 3) independently of each other.

Here, the ESC 15 includes a plurality of control valves, a hydraulic pump that pressurizes the brake fluid pressure, an electric motor that drives the hydraulic pump, and a hydraulic pressure control reservoir that temporarily stores excess brake fluid ( Neither is shown) and is included. The ESC 15 (each control valve and electric motor) is connected to the ESC control device 17. The opening and closing of each control valve of the ESC 15 and the drive of the electric motor are controlled by the ESC control device 17. That is, the ESC control device 17 is an ESC control unit (ESC ECU) that controls the ESC 15. The ESC control device 17 is configured to include a microcomputer, and electrically drives and controls the ESC 15 (solenoid of each control valve, electric motor).

The ESC control device 17 individually drives and controls each control valve (solium) of the ESC 15 and the electric motor for the hydraulic pump to supply the brakes to the disc brakes 5 and 6 through the brake side piping portions 16A-16D. Control of depressurizing, holding, increasing or pressurizing the hydraulic pressure (wheel cylinder hydraulic pressure) is performed individually for each of the disc brakes 5 and 6.

In this case, the ESC control device 17 can execute the following controls (1)-(8) by controlling the operation of the ESC 15.
(1) Braking force distribution control that appropriately distributes braking force to each of the wheels 2 and 3 according to the ground contact load when the vehicle is braked.
(2) Anti-lock braking control (hydraulic ABS control) that automatically adjusts the braking force of each wheel 2 and 3 during braking to prevent locking (slip) of each wheel 2 and 3.
(3) Understeer and oversteer are performed while detecting skidding of each wheel 2 and 3 during running and automatically controlling the braking force applied to each wheel 2 and 3 regardless of the operation amount of the brake pedal 9. Vehicle stabilization control that suppresses and stabilizes the behavior of the vehicle.
(4) Slope start assist control that assists the start by maintaining the braking state on a slope (especially uphill).
(5) Traction control that prevents the wheels 2 and 3 from slipping when starting.
(6) Vehicle follow-up control that maintains a constant distance from the preceding vehicle.
(7) Lane departure avoidance control that keeps the driving lane.
(8) Obstacle avoidance control (automatic brake control, collision damage mitigation brake control) that avoids collision with obstacles in the vehicle traveling direction.

The ESC 15 directly supplies the hydraulic pressure generated in the master cylinder 12 to the disc brakes 5 and 6 (calipers 5A and 6B) during normal operation by the driver's brake operation. On the other hand, for example, when the anti-lock brake control or the like is executed, the hydraulic pressure of the disc brakes 5 and 6 is maintained by closing the control valve for increasing the pressure, and when the hydraulic pressure of the disc brakes 5 and 6 is reduced. The pressure reducing control valve is opened and the hydraulic pressures of the disc brakes 5 and 6 are discharged so as to escape to the hydraulic pressure control reservoir.

Furthermore, in order to perform stabilization control (sideslip prevention control) when the vehicle is running, when increasing or pressurizing the hydraulic pressure supplied to the disc brakes 5 and 6, the electric motor is operated with the supply control valve closed. The hydraulic pump is operated by a motor, and the brake fluid discharged from the hydraulic pump is supplied to the disc brakes 5 and 6. At this time, the brake fluid in the master reservoir 13 is supplied from the master cylinder 12 side to the suction side of the hydraulic pump.

Electric power from a battery 18 (or a generator driven by an engine), which is a vehicle power source, is supplied to the ESC control device 17 through a power supply line 19. As shown in FIG. 1, the ESC control device 17 is connected to the vehicle data bus 20. It is also possible to use a known ABS unit instead of the ESC15. Further, it is also possible to directly connect the master cylinder 12 and the brake side piping portion 16A-16D without providing the ESC 15 (that is, omitting it).

The vehicle data bus 20 constitutes a CAN (Controller Area Network) as a serial communication unit mounted on the vehicle body 1. A large number of electronic devices mounted on the vehicle (for example, various ECUs including the ESC control device 17, the parking brake control device 24, etc.) perform multiplex communication in the vehicle between them by the vehicle data bus 20. In this case, the vehicle information sent to the vehicle data bus 20 includes, for example, a brake operation detection sensor 10, an ignition switch, a seat belt sensor, a door lock sensor, a door open sensor, a seating sensor, a vehicle speed sensor, a steering angle sensor, and an accelerator sensor. (Accelerator operation sensor), Throttle sensor, Engine rotation sensor, Stereo camera, Millimeter wave radar, Gradient sensor (Inclination sensor), Shift sensor (Transmission data), Acceleration sensor (G sensor), Wheel speed sensor, Vehicle pitch direction Information (vehicle information) based on a detection signal (output signal) from a pitch sensor or the like that detects movement can be mentioned.

Further, vehicle information sent to the vehicle data bus 20 includes detection signals (information) from the W / C pressure sensor 21 and the M / C pressure sensor 22. The W / C pressure sensor 21 and the M / C pressure sensor 22 are connected to the ESC control device 17 in the same manner as the brake operation detection sensor 10, for example.

The W / C pressure sensor 21 as the wheel cylinder pressure detecting means is provided in each of the brake side piping portions 16A, 16B, 16C, 16D, and corresponds to the respective piping pressure (hydraulic pressure), that is, the piping pressure. The W / C hydraulic pressure P _{W / C} in the disc brakes 5 and 6 (calipers 5A and 6B) is detected individually. In FIG. 1, the W / C pressure sensor 21 is provided between the ESC 15 and the calipers 5A and 6B. For example, the W / C pressure sensor 21 may be provided in the ESC 15 (may be built-in). ).

One W / C pressure sensor 21 may be provided for one piping system. For example, in the case of X piping, one is provided in either the brake side piping portion 16A or 16D, and the brake side piping portion 16B or 16C. It may be configured to be provided in each of the above. Further, only one of the brake-side piping portions 16A and 16D and the brake-side piping portions 16B and 16C may be provided in any one system. Further, without providing the W / C pressure sensor 21 (omitted), the pressure inside the pipes (W) of the brake side piping portions 16A, 16B, 16C, 16D is obtained from the detection signal of the M / C pressure sensor 22 by the ESC control device 17. / C hydraulic pressure P _{W / C} ) may be estimated (calculated).

The M / C pressure sensor 22 as the master cylinder pressure detecting means is provided in each of the cylinder side hydraulic pressure pipes 14A and 14B, and corresponds to the respective pipe internal pressure (hydraulic pressure), that is, the pipe internal pressure (hydraulic pressure). the M / C hydraulic pressure P _{M / C} of the master cylinder 12 to plumbing (primary side, secondary side) is used to detect each. That, M / C pressure sensor 22 is for detecting the M / C hydraulic pressure _{P M / C} to be supplied to the disc brake 5,6 (caliper 5A, 6B). Although the M / C pressure sensor 22 is provided between the master cylinder 12 and the ESC 15 in FIG. 1, for example, the M / C pressure sensor 22 may be provided (or built-in) in the ESC 15. .. Further, only one M / C pressure sensor 22 may be provided, and for example, it may be provided only on the primary side.

Further, the booster 11 may be provided with a stroke sensor, and the M / C hydraulic pressure PM _{/ C} may be estimated and calculated (calculated) from the stroke detected by the stroke sensor. As this stroke sensor, the M / C hydraulic pressure PM _{/ C} is estimated (calculated) from the operation amount (stroke amount) detected by the brake operation detection sensor 10 provided on the brake pedal 9 instead of the booster 11. You may. When an electric actuator (electric motor) is used as the booster 11, the M / C hydraulic pressure PM _{/ C} may be estimated (calculated) from the current value or stroke amount (operating amount) of the electric actuator. .. Of course, if the electric actuator has a built-in pressure sensor, the M / C hydraulic pressure PM _{/ C} may be estimated and calculated (calculated) using the detected value of the pressure sensor.

The detection signals of the W / C pressure sensor 21 and the M / C pressure sensor 22 or the estimated calculated value of the hydraulic pressure are the W / C hydraulic pressure P _{W / C} and the M / C hydraulic pressure PM _{/ C.} As information, it is sent to the vehicle data bus 20. A large number of electronic devices (various ECUs) mounted on the vehicle obtain various vehicle information including W / C hydraulic pressure P _{W / C} and M / C hydraulic pressure PM _{/ C} through the vehicle data bus 20. be able to.

Next, the parking brake switch 23 and the parking brake control device 24 will be described.

A parking brake switch (PKB-SW) 23 as an operation switch is provided in the vehicle body 1 at a position near the driver's seat (not shown). The parking brake switch 23 serves as an operation instruction unit operated by the driver. The parking brake switch 23 sends a signal (operation request signal) corresponding to a parking brake operation request (holding request apply request, release request release request) in response to the driver's operation instruction to the parking brake control device 24. Communicate to. That is, the parking brake switch 23 is an operation request signal (holding request) for operating the piston 6D and the brake pad 6C based on the drive (rotation) of the electric motor 7A to apply operation (hold operation) or release operation (release operation). An apply request signal as a signal and a release request signal as a release request signal are output to the parking brake control device 24 which is a parking brake control unit (parking brake ECU).

When the parking brake switch 23 is operated by the driver to the braking side (apply side), that is, when there is an apply request (braking holding request) for applying a braking force to the vehicle, the parking brake switch 23 applies. A request signal (parking brake request signal, apply command) is output. In this case, electric power for rotating the electric motor 7A to the braking side is supplied to the electric motor 7A of the rear wheel side disc brake 6 via the parking brake control device 24. At this time, the pressing member holding mechanism 8 propels (presses) the piston 6D toward the disc rotor 4 based on the rotation of the electric motor 7A, and holds the propelled piston 6D. As a result, the rear wheel side disc brake 6 is in a state in which a braking force as a parking brake (or an auxiliary brake) is applied, that is, an apply state (braking holding state).

On the other hand, when the parking brake switch 23 is operated by the driver to the braking release side (release side), that is, when there is a release request (braking release request) for releasing the braking force of the vehicle, the parking brake switch A release request signal (parking brake release request signal, release command) is output from 23. In this case, electric power for rotating the electric motor 7A in the direction opposite to the braking side is supplied to the electric motor 7A of the rear wheel side disc brake 6 via the parking brake control device 24. At this time, the pressing member holding mechanism 8 releases the holding of the piston 6D by the rotation of the electric motor 7A (the pressing force by the piston 6D is released). As a result, the rear wheel side disc brake 6 is in a state in which the braking force applied as the parking brake (or auxiliary brake) is released, that is, in the released state (braking release state).

The parking brake stops the engine, for example, when the vehicle has stopped for a predetermined time (for example, it is determined that the parking brake has stopped when the detection speed of the vehicle speed sensor has been less than 5 km / h for a predetermined time due to deceleration while driving). When, when the shift lever is operated to P, when the door opens, when the seat belt is released, etc., based on the automatic apply request by the parking brake apply determination logic in the parking brake control device 24, etc. It can be configured to be automatically given (auto-applied). Further, the parking brake is used, for example, when the vehicle is traveling (for example, it is determined that the parking brake is traveling when the detection speed of the vehicle speed sensor continues to be 6 km / h or more for a predetermined time as the speed increases from the stop). When operated, when the clutch pedal is operated, when the shift lever is operated other than P and N, etc., based on the automatic release request by the parking brake release determination logic in the parking brake control device 24, etc. It can be configured to be automatically released (auto-released). The auto apply and auto release can be configured as a switch failure auxiliary function that automatically applies or releases the braking force when the parking brake switch 23 fails.

Further, when there is an apply request by the parking brake switch 23 when the vehicle is running, more specifically, a request for a dynamic parking brake (dynamic apply) such as urgently using the parking brake as an auxiliary brake while driving. Even if there is, the parking brake control device 24 applies and releases the braking force according to the operation of the parking brake switch 23. For example, the parking brake control device 24 applies a braking force while the parking brake switch 23 is being operated on the braking side (while the operation on the braking side is continuing), and when the operation is completed, the braking force is applied. To cancel. At this time, the parking brake control device 24 automatically applies and releases the braking force (ABS control) according to the state of the wheels (each rear wheel 3), that is, whether or not the wheels lock (slip). It can be configured to be performed.

The parking brake control device 24 as a control device constitutes an electric brake device (electric parking brake device) together with the caliper 6B, the piston 6D, the electric motor 7A, and the pressing member holding mechanism 8 of the rear wheel side disc brake 6. As shown in FIG. 3, the parking brake control device 24 has an arithmetic circuit (CPU) 25 configured by a microcomputer or the like, and the parking brake control device 24 includes a battery 18 (or a generator driven by an engine). The power from is supplied through the power supply line 19.

The parking brake control device 24 controls the drive of the electric motors 7A and 7A of the rear wheel side disc brakes 6 and 6, and brakes (parking brake, auxiliary brake) when the vehicle is parked or stopped (when traveling as necessary). ) Is generated. That is, the parking brake control device 24 operates (applies and releases) the disc brakes 6 and 6 as parking brakes (auxiliary brakes if necessary) by driving the left and right electric motors 7A and 7A. For this purpose, the parking brake control device 24 has an input side connected to the parking brake switch 23 and an output side connected to the electric motors 7A and 7A of the disc brakes 6 and 6.

The parking brake control device 24 is left and right based on an operation request (apply request, release request) by the driver's operation of the parking brake switch 23, an operation request by the parking brake apply / release determination logic, and an operation request by ABS control. The electric motors 7A and 7A of the above are driven to apply (hold) or release (release) the left and right disc brakes 6 and 6. At this time, in the rear wheel side disc brake 6, the piston 6D and the brake pad 6C are held or released by the pressing member holding mechanism 8 based on the drive of each electric motor 7A. In this way, the parking brake control device 24 responds to the operation request signal for the holding operation (apply) or the release operation (release) of the piston 6D (and thus the brake pad 6C), and the piston 6D (and thus the brake) The electric motor 7A is driven and controlled to propel the pad 6C).

As shown in FIG. 3, in the arithmetic circuit 25 of the parking brake control device 24, in addition to the memory 26 as a storage unit, the parking brake switch 23, the vehicle data bus 20, the voltage sensor unit 27, the motor drive circuit 28, and the current The sensor unit 29 and the like are connected. From the vehicle data bus 20, various state quantities of the vehicle required for controlling (operating) the parking brake, that is, various vehicle information can be acquired.

The vehicle information acquired from the vehicle data bus 20 may be acquired by directly connecting a sensor for detecting the information to the parking brake control device 24 (calculation circuit 25). Further, the arithmetic circuit 25 of the parking brake control device 24 is such that an operation request based on the above-mentioned determination logic and ABS control is input from another control device (for example, ESC control device 17) connected to the vehicle data bus 20. It may be configured. In this case, the parking brake apply / release determination and ABS control by the above-mentioned determination logic can be performed by another control device, for example, the ESC control device 17, instead of the parking brake control device 24. .. That is, it is possible to integrate the control contents of the parking brake control device 24 into the ESC control device 17.

The parking brake control device 24 includes a memory 26 as a storage unit including, for example, a flash memory, a ROM, a RAM, an EEPROM, and the like. The memory 26 stores the parking brake apply / release determination logic and the ABS control program. In addition to this, the memory 26 has a processing program for executing the processing flow shown in FIGS. 4 to 6 described later, that is, a processing program used for control processing when the parking brake is applied, in the upper left of FIG. The relationship between the temperature shown and the pressing force, the relationship between the restart hydraulic pressure value shown in the lower right of FIG. 8 and the pressing force increase amount due to the hydraulic pressure, the pressing force decrease amount due to heat shrinkage and the pressing force due to the hydraulic pressure shown in FIG. The relationship between the difference from the increase amount and the target current value is stored. Further, the memory 26 stores the current state (status) of the parking brake by the electric motor 7A, that is, whether it is in the apply state or the release state. In this case, the state of the parking brake is renewably stored in the memory 26 every time the state is changed.

In the embodiment, the parking brake control device 24 is separated from the ESC control device 17, but the parking brake control device 24 may be integrally configured with the ESC control device 17. Further, although the parking brake control device 24 controls two rear wheel side disc brakes 6 and 6 on the left and right, it may be provided for each of the left and right rear wheel side disc brakes 6 and 6. In that case, each parking brake control device 24 may be integrally provided on the rear wheel side disc brake 6.

As shown in FIG. 3, the parking brake control device 24 includes a voltage sensor unit 27 that detects a voltage from the power supply line 19, left and right motor drive circuits 28 and 28 that drive the left and right electric motors 7A and 7A, respectively, and left and right. The left and right current sensor units 29, 29 and the like for detecting the motor currents of the electric motors 7A and 7A are built-in. The voltage sensor unit 27, the motor drive circuit 28, and the current sensor unit 29 are each connected to the arithmetic circuit 25.

As a result, in the arithmetic circuit 25 of the parking brake control device 24, when the parking brake is applied, the electric motors 7A and 7A are based on the current values of the electric motors 7A and 7A detected by the current sensors 29 and 29. The drive can be stopped. That is, the parking brake control device 24 drives the electric motor 7A until the pressing force of the piston 6D reaches the target pressing force value in response to the parking brake request signal by the parking brake switch 23 or the above-mentioned parking brake operation determination logic or the like. To do. At this time, the parking brake control device 24 sets the target pressing force value according to the target current value for driving the electric motor 7A. That is, when the parking brake control device 24 propels the piston 6D by driving (rotating) the electric motor 7A to apply a braking force, the parking brake control device 24 drives the electric motor 7A until the target current value corresponding to the target pressing force value is reached. To do.

By the way, according to the above-mentioned Patent Document 1, when the electric parking brake is applied (operated), it is reapplied after a lapse of a predetermined time from the application in consideration of a decrease in braking force due to heat shrinkage of the disc and the brake pad. Reclamp). However, when the electric parking brake is applied, if the hydraulic pressure in the caliper cylinder (foil cylinder hydraulic pressure) is large, the reapply may be performed even though the reapply is not necessary. That is, if the wheel cylinder hydraulic pressure (W / C hydraulic pressure) is large when the operation of the electric parking brake is completed, the thrust (pushing pressure) required for stopping the vehicle can be secured even if the brake pads are thermally contracted. There is sex. For this reason, for example, if the configuration is such that the restart (reclamp) is performed simply on the condition of temperature or the passage of time, unnecessary restart is performed, and unnecessary power may be consumed.

Therefore, in the embodiment, unnecessary re-operation is restricted (suppressed) by deciding whether or not re-operation (re-apply) is possible according to the hydraulic pressure when the electric parking brake is operated (applied). That is, in the embodiment, the reapply operation when the temperature of the disc rotor 4 and the brake pad 6C is high is unnecessary when the hydraulic pressure is high (when the hydraulic pressure is equal to or higher than a predetermined pressure), so that wasteful power consumption is consumed. Avoid (energy consumption).

For this purpose, the parking brake control device 24 has a temperature acquisition means for acquiring the temperature of the disc rotor 4 or the brake pad 6C. The temperature acquisition means may be configured to detect the actual temperature from a temperature sensor that detects the temperature of the rear wheel side disc brake 6, and may be configured to calculate (estimate) the temperature with the parking brake control device 24. Can be done. In this case, the temperature of the disc rotor 4 or the brake pad 6C is estimated (calculated) from information such as hydraulic pressure and wheel speed obtained from the vehicle data bus 20, for example, as described in the above-mentioned Patent Document 1 and the like. can do.

Further, the parking brake control device 24 controls the operation of the electric motor 7A, stops the operation of the electric motor 7A when the holding operation by the pressing member holding mechanism 8 is completed, and then presses the brake pad 6C against the disc rotor 4. The electric motor 7A is operated in the direction. In other words, the parking brake control device 24 controls the operation of the electric motor 7A, and restarts the electric motor 7A after the holding operation by the pressing member holding mechanism 8 is completed. That is, the parking brake control device 24 controls the operation (drive) of the electric motor 7A to apply (hold) and release (release) the parking brake. In addition to this, the parking brake control device 24 restarts (reapplies) the electric motor 7A after a predetermined time has elapsed from the completion of the holding operation (applying). In this case, the parking brake control device 24 is the electric motor in the direction of pressing the brake pad 6C against the disc rotor 4 based on the hydraulic pressure information to the piston 6D when the holding operation by the electric motor 7A and the pressing member holding mechanism 8 is completed. Limit the operation of 7A. That is, the parking brake control device 24 limits (suppresses) the restart of the electric motor 7A based on the hydraulic pressure information to the piston 6D when the holding operation by the electric motor 7A and the pressing member holding mechanism 8 is completed.

More specifically, the parking brake control device 24 discs the brake pad 6C when the hydraulic pressure at the completion of the holding operation by the electric motor 7A and the pressing member holding mechanism 8 is equal to or higher than a predetermined value (restarting hydraulic pressure value). The operation of the electric motor 7A in the direction of pressing the rotor 4 is restricted. That is, in this case, in order to suppress the restart of the electric motor 7A, the restart is not performed (restart is prohibited). In short, the parking brake control device 24 is based on the hydraulic pressure information (hydraulic pressure at the completion of the holding operation) at the time of normal operation (operation according to the apply command from the driver or the like) performed before the restart, and then thereafter. Judge the necessity of restarting. Then, when the hydraulic pressure at the time of normal operation (more specifically, the hydraulic pressure at the completion of holding operation) is high (more than a predetermined value), it is determined that restart is unnecessary, and restart after normal operation is performed. Restrict (prohibit) operation.

On the other hand, when the hydraulic pressure at the completion of the holding operation by the electric motor 7A and the pressing member holding mechanism 8 is less than a predetermined value (restarting hydraulic pressure value), the parking brake control device 24 uses the brake pad 6C as a disc rotor. The electric motor 7A is operated in the direction of pressing against 4. That is, the electric motor 7A is restarted (restarting is permitted). In short, the parking brake control device 24 restarts the electric motor 7A after a predetermined time has elapsed from the completion of the holding operation of the electric motor 7A and the pressing member holding mechanism 8. For a predetermined time, before the braking force of the rear wheel side disc brake 6 becomes smaller than the braking force required to maintain the vehicle stop due to the decrease in the braking force due to the thermal contraction of the disc rotor 4 and the brake pad 6C. It is set so that the restart (reapply) of the electric motor 7A is started.

Such a predetermined time is obtained in advance by, for example, calculation, experiment, simulation, or the like. In addition, the predetermined time can be set to a preset fixed value, for example, the temperature of the disc rotor 4 or the brake pad 6C at the time of application (more specifically, at the time of completion of application), and the liquid at the time of application. It can be made variable according to the pressure and the like. The control of the electric motor 7A by the parking brake control device 24 will be described in detail later.

The brake system of the four-wheeled vehicle according to the embodiment has the above-described configuration, and its operation will be described next.

When the driver of the vehicle depresses the brake pedal 9, the pedaling force is transmitted to the master cylinder 12 via the booster 11, and the brake fluid pressure is generated by the master cylinder 12. The brake fluid pressure generated in the master cylinder 12 is distributed to the disc brakes 5 and 6 via the cylinder side hydraulic pressure pipes 14A, 14B, ESC15 and the brake side piping portions 16A, 16B, 16C, 16D, and the left and right front wheels. Braking force is applied to 2 and the left and right rear wheels 3, respectively.

In this case, in the disc brakes 5 and 6, the pistons 5B and 6D are slidably displaced toward the brake pads 6C as the brake fluid pressure in the calipers 5A and 6B rises, and the brake pads 6C are the disc rotors 4 and 4. Is pressed against. As a result, a braking force based on the brake fluid pressure is applied. On the other hand, when the brake operation is released, the supply of the brake fluid pressure into the calipers 5A and 6B is stopped, so that the pistons 5B and 6D are displaced so as to be separated (backward) from the disc rotors 4 and 4. As a result, the brake pads 6C are separated from the disc rotors 4 and 4, and the vehicle is returned to the non-braking state.

Next, when the driver of the vehicle operates the parking brake switch 23 to the braking side (apply side), power is supplied from the parking brake control device 24 to the electric motors 7A and 7A of the rear wheel side disc brakes 6 and 6. , The electric motors 7A and 7A are rotationally driven. In the rear wheel side disc brakes 6 and 6, the rotary motion of the electric motors 7A and 7A is converted into a linear motion by the pressing member holding mechanisms 8 and 8, and the pistons 6D and 6D are propelled by the rotary linear motion members 8A and 8A. As a result, the disc rotors 4 and 4 are pressed by the brake pads 6C and 6C. At this time, the pressing member holding mechanism 8 (rotary linear motion members 8A, 8A) is held in a braking state by, for example, a frictional force (holding force) due to screwing. As a result, the rear wheel side disc brakes 6 and 6 are operated (applied) as parking brakes. That is, even after the power supply to the electric motors 7A and 7A is stopped, the pistons 6D and 6D are held in the braking position by the pressing member holding mechanisms 8 and 8.

On the other hand, when the driver operates the parking brake switch 23 to the braking release side (release side), power is supplied from the parking brake control device 24 to the electric motors 7A and 7A so that the motors reverse. By this power supply, the electric motors 7A and 7A are rotated in the direction opposite to that when the parking brake is operated (when applied). At this time, the holding of the braking force by the pressing member holding mechanism 8 is released, and the piston 6D can be displaced in the direction away from the disc rotor 4. As a result, the rear wheel side disc brakes 6 and 6 are released from the operation as parking brakes.

Next, the control process performed by the arithmetic circuit 25 of the parking brake control device 24 will be described with reference to FIGS. 4 to 6. The left electric motor 7A and the right electric motor 7A, which are built in the electric actuators 7 and 7 of the left and right rear wheel side disc brakes 6 and 6, respectively, perform the same control processing. Therefore, the control process of one of the electric motors 7A will be described below. Further, the process of FIG. 4 corresponds to the main process of the apply control process, the process of FIG. 5 corresponds to the process of S9 in FIG. 4 (reapply necessity determination process), and the process of FIG. 6 corresponds to the process of FIG. Corresponds to the process of S10 in FIG. 4 (reapply start determination process). Further, the control process of FIG. 4 is repeatedly executed, for example, in a predetermined control cycle, that is, every predetermined time (for example, 10 ms) while the parking brake control device 24 is energized.

When the control process of FIG. 4 is started, the parking brake control device 24 determines in S1 whether or not the flag F1 is ON. This flag F1 is an apply flag F1 for determining whether or not the electric motor 7A is being driven (rotating), in other words, whether or not to proceed to S6 without going through the processes of S2 to S5. Is. As will be described later, the apply operating flag F1 is turned on in S4 or S25 when the electric motor 7A is started to be driven. Further, the apply operating flag F1 is turned off in S7 immediately before the electric motor 7A is stopped.

When "YES" in S1, that is, when the applying flag F1 is determined to be on (applying), the electric motor 7A is being driven (applying), so the process from S2 to S5 is performed. Proceed to S6 without. On the other hand, when "NO" in S1, that is, when the applying flag F1 is determined to be OFF, the electric motor 7A is not being driven (stopped), so the process proceeds to S2.

In S2, it is determined whether or not the parking brake is in the released state and there is an apply instruction (command / request) by the parking brake switch 23 or the like. If it is determined in S2 that "NO", that is, the parking brake is not in the released state or there is no apply instruction, the process proceeds to S10 described later. On the other hand, if it is determined in S2 as "YES", that is, in the release state and there is an apply instruction, the process proceeds to S3.

In S3, the target current value Am and the restart hydraulic pressure value Pm are set by the characteristic line 38 in the lower right of FIG. 8 (and the characteristic line 39 of FIG. 9 if necessary). Details will be described later. After setting the target current value Am and the restart hydraulic pressure value Pm in S3, in the subsequent S4, the apply operating flag F1 is turned on. In the following S5, the electric motor 7A is driven to the apply side (the direction in which the rotary linear motion member 8A is directed toward the disc rotor 4), and the process proceeds to S6. In S6, it is determined whether or not the motor stop condition is satisfied. The motor stop condition is a condition for determining whether or not to stop the electric motor 7A.

Whether or not the motor stop condition is satisfied is determined by whether or not both of the following (i) and (ii) are satisfied.
(I) A predetermined time has elapsed since the driving of the electric motor 7A was started.
(Ii) The current value of the electric motor 7A became equal to or higher than the target current value Am set in S3 (or S24 described later), and continued for a predetermined time.

The predetermined time (i) can be set as a time until the inrush current due to the start of the electric motor 7A becomes sufficiently small. The predetermined time of (ii) can be set as a time during which it can be determined that the target current value Am has been reached, that is, a time during which it can be determined that the target current value Am has been reached without erroneous determination due to noise or the like.

If it is determined in S6 that "NO", that is, the motor stop condition is not satisfied, the process returns to the start via the end. Then, after a predetermined time, the process proceeds from the start to S1, and the processing after S1 is repeated. On the other hand, if "YES" in S6, that is, if it is determined that the motor stop condition is satisfied, the process proceeds to S7. In S7, the flag F1 during the apply operation is cleared (off). In the following S8, the electric motor 7A is stopped and the process proceeds to S9.

In S9, the reapply necessity determination process is performed. Specifically, the process shown in FIG. 5 is performed. When the reapply necessity determination process is started, in S11, it is determined whether or not the flag F3 is on. This flag F3 is a flag for determining whether or not the stop of the electric motor 7A in the immediately preceding S8 is a stop due to restart (when the application is completed due to restart). In other words, the flag F3 is a restart flag F3 that is off when it is necessary to proceed to determine whether or not to perform a restart (reapply) and is turned on when a restart is required. As will be described later, the restart flag F3 is turned on in S15 when it is necessary to perform the restart. Further, the restart flag F3 is turned off in S14 after the restarted electric motor 7A is stopped.

When "YES" in S11, that is, when the restart flag F3 is determined to be ON, in order to correspond to the timing when the restarted electric motor 7A is stopped (when the application is completed by restarting), S12, S13, S15 Proceed to S14 without going through the process. In this case, the restart flag F3 is cleared in S14. As a result, the restart flag F3 is turned off after the restart is completed. After turning off the restart flag F3 in S14, the process returns to FIG. 4 via the return and proceeds to the end. That is, the process returns to the start via the end of FIG. 4, and after a predetermined time, the process proceeds from the start to S1.

On the other hand, when "NO" in S11, that is, when the restart flag F3 is determined to be off, it corresponds to the timing when the electric motor 7A starts driving from the released state and stops. That is, it corresponds to the timing when the electric motor 7A is stopped at the first application (before reoperation) (when the application is completed by the first operation). In this case, the process proceeds to S12 and S13 (progresses to determine whether or not to restart).

In S12, P information (hydraulic pressure information) is acquired. That is, in S12, the hydraulic pressure Pa of the current (current control cycle) rear wheel side disc brake 6 (inside the cylinder 6B1) is acquired from the vehicle data bus 20. For the hydraulic pressure Pa, for example, the value of the W / C pressure sensor 21 (W / C hydraulic pressure P _{W / C} ) or the value of the M / C pressure sensor 22 (M / C hydraulic pressure PM _{/ C} ) is used. be able to. The hydraulic pressure Pa is, for example, the detection amount (stroke amount) of the stroke sensor provided in the booster 11, the detection amount (stroke amount, pedaling force) of the brake operation detection sensor 10 provided in the brake pedal 9, and the booster 11. When the electric actuator is used as the above, it may be estimated (calculated) from the current value or the operating amount (stroke amount, rotation amount) of the electric actuator.

In the following S13, it is determined whether or not the hydraulic pressure Pa is equal to or higher than the restart hydraulic pressure value Pm set in S3. If "YES" in S13, that is, if it is determined that the hydraulic pressure Pa is equal to or higher than the restart hydraulic pressure value Pm, the process returns to FIG. 4 via the return. On the other hand, when it is determined in S13 that "NO", that is, the hydraulic pressure Pa is less than the restart hydraulic pressure value Pm, the restart (reapply) is required, so the restart flag F3 is turned on in S15. Then, it returns to FIG. 4 via a return.

Next, the reapply start determination process of S10 of FIG. 4 will be described. If it is determined in S2 of FIG. 4 that the parking brake is not in the released state or there is no apply instruction, the process proceeds to S10. In S10, the reapply start determination process is performed. Specifically, the process shown in FIG. 6 is performed. When the reapply start determination process is started, S21 determines whether or not the restart flag F3 is on. When it is determined in S21 that "NO", that is, the restart flag F3 is off, the electric motor 7A does not need to be restarted, so the process returns to FIG. 4 via the return. On the other hand, if "YES" in S21, that is, if it is determined that the restart flag F3 is on, the electric motor 7A needs to be restarted, so the process proceeds to S22.

In S22, it is determined whether or not there is a release command. That is, in S22, it is determined whether or not there is a release command from the completion of the first application to the start of the reapply (restart). If "YES" in S22, that is, if it is determined that there is a release command, the release command is in standby for restart (waiting for reapply). In this case, the parking brake is released, eliminating the need for reapplying. Therefore, in this case, the process proceeds from S23 to S26 without going through the process of S27, and the restart flag F3 is cleared (off) in S27. Then, it returns to FIG. 4 via the return.

On the other hand, if it is determined in S22 that "NO", that is, there is no release command, the process proceeds to S23. In S23, it is determined whether or not the reapply condition is satisfied. Here, the reapply condition is a condition for determining whether or not it is the timing for reapplying, in other words, whether or not the timing for starting the restart of the electric motor 7A has been reached. In the first embodiment, the reapply condition is set as the elapsed time from the completion of the first apply operation. That is, in S23, it is determined whether or not a predetermined time has elapsed since the completion of the first apply operation.

The predetermined time can be set as the time until the pressing force approaches the pressing force required for stopping the vehicle body 1 due to heat shrinkage due to cooling (temperature drop) of the disc rotor 4 and the brake pad 6C. In this case, the predetermined time can be set as the time before the pressing force by the first apply becomes smaller than the pressing force required for stopping the vehicle. Further, the predetermined time can be made variable according to, for example, the temperature of the disc rotor 4 or the brake pad 6C at the time of application, the hydraulic pressure at the time of application (more specifically, at the time of completion of application), and the like. .. For example, the higher the hydraulic pressure at the completion of application, the longer the time can be set.

If it is determined in S23 that "NO", that is, the reapply condition is not satisfied, the process returns to FIG. 4 via a return. On the other hand, if "YES" in S23, that is, if it is determined that the reapply condition is satisfied, the process proceeds to S24. In S24, the target current value Am and the restart hydraulic pressure value Pm are set in the same manner as in S3 of FIG. Here, the target current value Am set in S24, that is, the target current value Am for restart (reapply) is set in S3 in consideration of the possibility that the hydraulic pressure cannot be obtained at the time of restart, for example. It may be set as a value larger than the target current value Am. After setting the target current value Am and the restart hydraulic pressure value Pm in S24, the apply operating flag F1 is turned on in the subsequent S25. In the following S26, the electric motor 7A is driven to the apply side, and the process returns to FIG. 4 via the return.

When the driver turns off the ignition switch and gets off the vehicle, the parking brake control device 24 is usually turned off like other in-vehicle systems. However, when the restart flag F3 is on, power is supplied to the parking brake control device 24 until a predetermined time elapses and the reapply operation is completed (the process shown in FIGS. 4 to 6 is continued). To do).

Next, an example when the processing of FIGS. 4 to 6 is performed by the parking brake control device 24 will be described with reference to FIGS. 7 to 9. Note that FIG. 7 is a characteristic diagram (time chart) showing changes in the hydraulic pressure Pa and the pressing pressure F over time. FIG. 8 is a characteristic diagram showing the relationship between the temperature TMP, the pressing force F, the hydraulic pressure Pa, the restarting hydraulic pressure value Pm, and the pressing force increase amount ΔF. More specifically, the upper left of FIG. 8 shows an example of the relationship between the temperature TMP and the pressing force F, and the upper right of FIG. 8 shows an example of the relationship between the hydraulic pressure Pa and the pressing force F when the application is completed. The lower right of FIG. 8 shows an example of the relationship between the restart hydraulic pressure value Pm and the pressing pressure increase amount ΔF due to the hydraulic pressure. The value of the temperature TMP in the upper left of FIG. 8 increases (the temperature increases) as it goes to the left. The value of the pressing force increase amount ΔF in the lower right of FIG. 8 increases as it goes downward (the pressing force increase amount increases). FIG. 9 is a characteristic diagram showing the relationship between the difference (ΔFt−ΔFp) between the pressing pressure decrease amount ΔFt due to heat shrinkage and the pressing pressure increase amount ΔFp due to hydraulic pressure and the target current value Am.

As shown in FIG. 7, when the brake pedal 9 is started to be depressed at time t1, the hydraulic pressure Pa supplied to the rear wheel side disc brake 6 rises and is applied to the brake pad 6C based on the hydraulic pressure Pa. The pressing force F increases. The characteristic lines 31, 32, and 33 in FIG. 7 correspond to the time change when the hydraulic pressure at the completion of application is high (in the case of the hydraulic pressure P12 which does not need to be restarted), and are shown by the broken lines in FIG. The characteristic lines 34, 35, and 36 correspond to the time change when the hydraulic pressure at the completion of application is low (in the case of the hydraulic pressure P11 requiring restart). Further, the characteristic lines 32 and 35 correspond to the pressing force (load) F applied to the brake pad 6C, and the characteristic lines 33 and 36 correspond to the pressing force (load) F applied to the pressing member holding mechanism 8.

At time t2 in FIG. 7, an apply command is input to the parking brake control device 24 in a state where a pressing force due to the hydraulic pressure P12 or the hydraulic pressure P11 is generated. As a result, the pressing force F increases based on the drive of the electric motor 7A. Here, when the pressing force required to maintain the vehicle body 1 stopped is F10 and the target pressing force is F11 equal to F10, the corresponding target current value Am is set to A11. In this case, the target current value A11 corresponds to the current value at which the pressing force F10 is obtained when the hydraulic pressure Pa = 0. Further, if the target current value A11 is applied while the hydraulic pressure is generated, the pressing force F11 is added to the pressing force due to the hydraulic pressure.

The target current value Am set in S3 of FIG. 4 may be set to A11, or may be set to a value larger than A11 in consideration of the possibility that the apply operation is performed without the brake pedal 9 being depressed. It may be set. Further, since the target current value Am set in S24 of FIG. 6 is the target current value Am at the time of restart, for example, it is larger than the target current value Am at the time of initial operation set in S3 of FIG. You may. Here, the target current value Am will be described as A11. The characteristic line 39 shown in FIG. 9, which will be described later, that is, the characteristic for setting the target current value Am from the difference (ΔFt−ΔFp) between the pressing pressure decrease amount ΔFt due to heat shrinkage and the pressing pressure increase amount ΔFp due to hydraulic pressure. The line Am1'will be described later.

At time t2 in FIG. 7, the estimated temperature of the disc rotor 4 or the brake pad 6C is TMP12, and the minimum set temperature in consideration of the change in the temperature during parking is TMP11. In this case, the amount of decrease in pressing force due to heat shrinkage of the disc rotor 4 and the brake pad 6C is ΔFt11 from the characteristic line 37 on the upper left of FIG. 8, that is, the characteristic line Tm1 which is the relationship between the temperature TMP and the pressing force F. .. Here, the minimum set temperature TMP11 is a temperature set according to the usage environment of the vehicle and the like. That is, the minimum set temperature TMP11 is a design requirement, but can be set to a value such as 0 ° C. or −40 ° C. in consideration of cold regions, for example. The characteristic line 37 of FIG. 8 can be obtained in advance by, for example, calculation, experiment, simulation, or the like. Further, the temperature of the disc rotor 4 or the brake pad 6C can be calculated (estimated) from information obtained from the vehicle data bus 20 such as hydraulic pressure and wheel speed, as described in the above-mentioned Patent Document 1 and the like. it can.

At time t2, when the pressing pressure decrease amount ΔFt11 due to heat shrinkage is obtained from the temperature TMP12 at that time, the restart hydraulic pressure value Pm, that is, the restart hydraulic pressure that becomes the determination value (threshold value) of whether or not to perform the restart. The value Pm is set to P13 using the characteristic line 38 at the lower right of FIG. 8, that is, the characteristic line Pm1 which is the relationship between the restarting hydraulic pressure value Pm and the pressing pressure increase amount ΔF due to the hydraulic pressure. The characteristic line Pm1 can be predetermined from the amount of increase in the pressing force remaining when the apply operation is completed while the hydraulic pressure is acting and then the hydraulic pressure is released. At time t2, the pressing pressure reduction amount ΔFt11 is determined from the temperature TMP = TMP12 at that time under the target current value Am = A11 by the processing of S3 in FIG. 4, and the pressing pressure reduction amount ΔFt11 is equivalent to this pressing pressure reduction amount ΔFt11. The restart hydraulic pressure value Pm = P13 corresponding to the hydraulic pressure value required to obtain the pressure increase amount is determined.

When the first apply operation is completed at time t3, F11 driven by the electric motor 7A is added to the pressing force. Here, assuming that the hydraulic pressure Pa at time t3 is P12, the pressing pressure is F15 in total. At this time, since the hydraulic pressure P12 is larger than the restart hydraulic pressure value Pm = P13 (see the lower right of FIG. 8), it is determined as “YES” in S13 of FIG. 5, and the process does not proceed to S15. That is, the restart flag F3 is not turned on, remains off, and the reapply operation is not performed.

Next, when the hydraulic pressure is released, the pressing member holding mechanism until the load applied to the cylinder portion 6B3, the bridge portion 6B4, the claw portion 6B2 and the brake pad 6C of the caliper 6B and the load applied to the pressing member holding mechanism 8 are balanced. Since 8 is elastically deformed, the pressing force is slightly reduced and becomes F14 at time t4. The pressing force at this time is ΔFp12 minutes larger than that of F11 by the electric motor 7A because the hydraulic pressure P12 is generated at the time of applying.

After that, with the passage of time, the temperatures of the disc rotor 4 and the brake pad 6C decrease, and the pressing force decreases by ΔFt11 minutes at time t6 due to heat shrinkage, but the pressing force F10 required for stopping the vehicle body 1 can be secured. is made of.

As described above, when the hydraulic pressure Pa is equal to or higher than the restart hydraulic pressure value Pm, the pressing force can be secured without reapplying even if the temperatures of the disc rotor 4 and the brake pad 6C are high. This is because the amount of decrease in pressing force due to heat shrinkage is ΔFt11, whereas the amount of increase in pressing force due to hydraulic pressure is ΔFp12, which is larger than ΔFt11. According to the embodiment, the necessity of reapplying can be determined by the hydraulic pressure Pa at the time of applying (when applying is completed).

On the other hand, when the hydraulic pressure Pa at time t3 is P11, which is smaller than P13, the pressing force becomes F13 even if the hydraulic pressure is added, and the pressing force becomes F12 at time t4 after the hydraulic pressure is released. That is, the increase in the pressing force due to the hydraulic pressure is ΔFp11, which is smaller than ΔFt11. In this case, since the hydraulic pressure P11 is smaller than the restart hydraulic pressure value Pm = P13 at time t3 (see the lower right of FIG. 8), it is determined as "NO" in S13 of FIG. 5, and the restart flag is in S15. Is turned on. As a result, in the embodiment, before the pressing force falls below the required pressing force F10 at time t5, "YES" is determined in S23 of FIG. 6, and the electric motor 7A is driven in the following S26 to perform reapply. Be told. The broken line characteristic line 35 in FIG. 7 shows a case where the pressing force falls below the required pressing force F10 without reapplying.

Here, at the time of reapply, the driver may get off and the hydraulic pressure may not be obtained. Therefore, the target current value Am at the time of reapply, that is, the target current value Am set in S24 is energized from A11. You may raise it to the extent possible. For example, the target current value Am is not constant and can be set as the characteristic line 39 shown in FIG. 9, that is, the characteristic line Am1'. In this case, the target current value Am is a value obtained according to ΔFt−ΔFp. Here, ΔFt−ΔFp corresponds to the difference between the pressing pressure decrease amount ΔFt due to the temperature decrease (heat shrinkage) and the pressing pressure increase amount ΔFp due to the hydraulic pressure, that is, the insufficient pressing force.

In the present embodiment, if the temperature at the completion of application is TMP12, ΔFt−ΔFp = 0 when the hydraulic pressure Pa = P13. Here, in the positive range (ΔFt> ΔFp) on the right side where the pressing force is insufficient, if the target current value Am is raised to A12, which is larger than A11, the condition for reapplying is the broken line 40, which requires A12 or more. Is limited to the range of. As a result, the frequency of reapplying can be further reduced. Note that A12 can be, for example, a maximum current value (a current value capable of generating a maximum pressing force).

Thus, in the first embodiment, unnecessary restart (reapply) can be restricted (suppressed).

That is, in the first embodiment, the parking brake control device 24 restarts the electric motor 7A based on the hydraulic pressure information Pa to the piston 6D when the holding operation by the electric motor 7A and the pressing member holding mechanism 8 is completed. Limit (suppress). More specifically, when the parking brake control device 24 determines that the hydraulic pressure Pa at the completion of the holding operation is equal to or higher than a predetermined value (restarting hydraulic pressure value) by the processes of S12 and S13 of FIG. Do not proceed to S15. In this case, the predetermined value (restarting hydraulic pressure value) can be set as, for example, the hydraulic pressure P13 capable of obtaining the pressing pressure increase amount ΔF corresponding to the pressing pressure decrease amount ΔFt11 determined from the temperature TMP12 at the time of application. Therefore, when the hydraulic pressure when applied at the temperature TMP12 is P13 or higher, the restart flag F3 is not turned on and the restart is prohibited. At this time, the pressing force can be maintained at F10 or higher without restarting. That is, the vehicle can be maintained even if the temperature drops.

In other words, the parking brake control device 24 determines the necessity of restarting by the processing of S3, S12, and S13 in consideration of the pushing pressure increase amount ΔFp due to the hydraulic pressure Pa at the completion of the holding operation. Then, when it is determined that the restart is not necessary, that is, when the pressing pressure increase amount ΔF corresponding to the pressing pressure decrease amount ΔFt11 due to the temperature decrease is obtained by the hydraulic pressure Pa at the completion of the application, the restarting is performed. Not done. As a result, unnecessary restart can be suppressed and power consumption can be reduced.

On the other hand, when the hydraulic pressure Pa at the completion of the holding operation is less than a predetermined value (for example, Pa <P13), the parking brake control device 24 has passed a predetermined time after the completion of the holding operation by the process of S23. (For example, when the time t5 in FIG. 7 is reached), the electric motor 7A is restarted by the process of S26. Therefore, when the pressing force is expected to be insufficient (when it is necessary to add the pressing force), the electric motor 7A can be restarted. As a result, the braking force (pushing pressure, thrust) by the electric motor 7A and the pressing member holding mechanism 8 can be secured.

In the first embodiment, a case where the electric motor 7A is reactivated when a predetermined time has elapsed from the completion of the holding operation has been described as an example. However, the present invention is not limited to this, and for example, when the temperature of the brake pad 6C becomes lower than the predetermined temperature after the holding operation is completed, the electric motor 7A may be restarted. In this case, the predetermined temperature is the braking force required to maintain the vehicle stop due to the braking force generated by the electric mechanism (electric motor 7A and pressing member holding mechanism 8), which is the same as the predetermined time, due to the decrease in braking force due to heat shrinkage. It is set so that the restart of the electric motor (electric motor 7A) is started before it becomes smaller than. The predetermined temperature or the predetermined time is, for example, immediately before the braking force by the electric mechanism decreases to the braking force required to maintain the stop of the vehicle from the target current value, the hydraulic pressure, and the temperature when the application is applied (when the holding operation is completed). It can be calculated as the time of time or the temperature immediately before. Then, when the determined time elapses or when the temperature becomes lower than the determined temperature, the electric motor 7A is restarted.

Next, FIG. 10 shows a second embodiment. In the first embodiment described above, the reapply operation when the temperature of the disc rotor 4 and the brake pad 6C is high is not required when the hydraulic pressure is high. On the other hand, in the second embodiment, the target pressing force (target current value) is changed according to the inclination (gradient) of the road surface on which the vehicle is stopped at the time of application, and the ignition switch is turned off. In the configuration in which the target pressing force (target current value) is maximized and reapplied when the vehicle is completely parked due to the above, the reapply is not required when the hydraulic pressure is high. Here, the reason for maximizing the target pressing force when reapplying in the fully parked state is to maintain the stop even when the road surface inclination changes while the vehicle is stopped, for example, when transporting a vehicle by ship. To make it.

That is, the feature of the second embodiment is that the target current value at which the minimum pressing force corresponding to the road surface inclination is obtained is applied, and the maximum target is when the vehicle is completely parked (when the driver gets off). In the configuration of reapplying with the current value, when the hydraulic pressure at the time of applying is high, the reapplying is unnecessary. In the second embodiment, the same components as those in the first embodiment are designated by the same reference numerals, and the description thereof will be omitted.

In the second embodiment, the parking brake control device 24 acquires, for example, an inclination angle (gradient) of the road surface on which the vehicle is stopped by an acceleration sensor. That is, the acceleration sensor is provided on the vehicle body 1 and detects the acceleration of the vehicle, for example, the acceleration in the front-rear direction of the vehicle. In this case, the acceleration sensor can also serve as a sensor (inclination detecting means) for detecting the inclination angle (inclination) of the road surface on which the vehicle is stopped. That is, not only the front-rear acceleration based on the acceleration and deceleration (braking) of the vehicle (front-back acceleration based on the running of the vehicle) is applied to the acceleration sensor, but also the gravitational acceleration according to the slope of the road surface (tilt of the vehicle) is added to the acceleration sensor. .. In other words, when the vehicle is stopped (stopped), the accelerometer is subjected to only the gravitational acceleration according to the slope of the road surface on which the vehicle is stopped (the slope of the vehicle).

Therefore, when the vehicle is stopped, the slope of the road surface (inclination amount, inclination angle) can be calculated based on the acceleration detected by the acceleration sensor. In this case, whether or not the vehicle is stopped can be detected, for example, from the detection signals of the wheel speed sensor or the vehicle speed sensor. The detection (or calculation) of the inclination angle of the road surface on which the vehicle is stopped detects (detects) the inclination of the road surface (inclination of the vehicle) of a sensor other than the acceleration sensor, for example, a gyro sensor, an inclination sensor, or an inclination sensor. ) A sensor that can be used may be used.

When the apply command is input, the parking brake control device 24 of the second embodiment drives the electric motor 7A until the pressing force of the piston 6D reaches the target pressing force value. Specifically, the parking brake control device 24 drives the electric motor 7A until the target current value corresponding to the target pressing force is reached. In this case, the target pressing force is set as follows. That is, as shown as a characteristic line 41 in the upper left of FIG. 10, the target pressing force value when the inclination angle G of the road surface is equal to or less than the predetermined angle Ga is set to the first predetermined pressing force value Fa, and the inclination angle of the road surface is set. The target pressing force value when G is larger than the predetermined pressing force value Ga is larger than the first predetermined pressing force value Fa, and increases from the first predetermined pressing force value Fa each time the inclination angle G of the road surface increases. It is set to the value of.

Along with this, the target current value Am for obtaining the target pressing force F is also set as follows. That is, as shown as the characteristic line 42 in the lower left of FIG. 10, the target current value when the inclination angle G of the road surface is equal to or less than the predetermined angle Ga is set to the first predetermined current value Aa, and the inclination angle G of the road surface is set. The target current value when the angle is larger than the predetermined current value Ga is set to be larger than the first predetermined current value Aa and to be larger than the first predetermined current value Aa each time the inclination angle G of the road surface is increased. ing.

The parking brake control device 24 of the second embodiment also controls the operation of the electric motor 7A as in the first embodiment, and restarts the electric motor 7A after the holding operation is completed. In the second embodiment, the parking brake control device 24 restarts the electric motor 7A after a predetermined time has elapsed from the completion of the holding operation, that is, when it is determined that the vehicle is completely parked (the driver has disembarked). (Reapply). In this case, the parking brake control device 24 limits (suppresses) the restart of the electric motor 7A when the hydraulic pressure on the piston 6D at the completion of the holding operation is equal to or higher than a predetermined value (restarting hydraulic pressure value). In short, the parking brake control device 24 is based on the hydraulic pressure information (hydraulic pressure at the completion of the holding operation) at the time of normal operation (operation according to the apply command from the driver or the like) performed before the restart, and then thereafter. Judge the necessity of restarting. Then, when the hydraulic pressure at the time of normal operation (more specifically, the hydraulic pressure at the completion of holding operation) is high (more than a predetermined value), it is determined that restart is unnecessary, and restart after normal operation is performed. Restrict (prohibit) operation.

The parking brake control device 24 of the second embodiment also performs the processes shown in FIGS. 4 to 6 as in the first embodiment. Since the parking brake control device 24 of the second embodiment basically performs the same processing as the processing of the first embodiment, a processing different from that of the first embodiment will be described here.

In the second embodiment, in S3 of FIG. 4, the target current value Am and the restart hydraulic pressure value Pm are set using the characteristic lines 41, 42, 43 of FIG. In this case, in S3 of FIG. 4, the target current value Am is set from the slope G at the time of application based on the characteristic line 42 at the lower left of FIG. Further, in S24 of FIG. 6, the target current value Am is set to, for example, the target current value Am = A22 at which the pressing force F = F22 required to maintain the vehicle stop at the maximum inclination G22 can be obtained. Details will be described later.

In the second embodiment, the determination in S23 of FIG. 6, that is, the determination as to whether or not the reapply condition is satisfied is performed as follows. The reapply condition is a condition for determining whether or not the timing for starting the restart of the electric motor 7A has been reached. In the second embodiment, the reapply condition is completely when the driver gets off the vehicle. It is set as a condition for determining whether or not the vehicle is parked.

Specifically, whether or not the reapply condition is satisfied (whether or not the vehicle is completely parked) is determined by whether or not both of the following (a) and (b) are satisfied.
(A) The ignition switch is OFF. In other words, the vehicle engine is stopped. The vehicle system is off. The accessory is off.
(B) The brake pedal 9 is not operated by the brake operation detection sensor 10 (the pedal switch is OFF).

The determination of (b), for example, W / C pressure by the pressure sensor 21 (W / C hydraulic pressure _{P W /} C), or, M / C pressure the pressure by the sensor 22 (M / C hydraulic pressure _{P M / C} ) may be used. In this case, when the pressure is 0, it is determined that the brake pedal 9 is not operated.

Further, in order to increase the reliability of the determination, in addition to (a) and (b), whether or not the following (c), (d), and (e) are satisfied may be appropriately added to the determination conditions. .. The information necessary for the determination of (a), (b), (c), (d), and (e) can be acquired, for example, via the vehicle data bus 20.
(C) The driver's door opened.
(D) The driver's seat belt was released.
(E) The seating sensor in the driver's seat is OFF (the driver is away).

Next, an example when the processing of FIGS. 4 to 6 is performed by the parking brake control device 24 will be described with reference to FIG. FIG. 10 is a characteristic diagram showing the relationship between the inclination G, the pressing force F, the hydraulic pressure Pa, the restarting hydraulic pressure value Pm, the pressing force increase amount ΔF, and the target current value Am. More specifically, the upper left of FIG. 10 shows an example of the relationship between the inclination G and the pressing force F, and the upper right of FIG. 10 shows an example of the relationship between the hydraulic pressure Pa at the completion of application and the pressing force F. The lower right of FIG. 10 shows an example of the relationship between the restart hydraulic pressure value Pm and the pressing pressure increase amount ΔF due to the hydraulic pressure, and the lower left of FIG. 10 shows the inclination G and the target current value Am. An example of the relationship with is shown. The values of the slopes G at the upper left and the lower left of FIG. 10 increase as they move to the left (the slope increases). The target current value Am in the lower left of FIG. 10 becomes larger (the current value becomes larger) as it goes downward. The value of the pressing force increase amount ΔF in the lower right of FIG. 10 increases as it goes downward (the pressing force increase amount increases).

First, before driving the electric motor 7A in response to the apply command, the target current value Am and the restart hydraulic pressure value Pm are determined based on the inclination G. That is, when an apply command is input to the parking brake control device 24, it is determined as "YES" in S2 of FIG. 4, and the target current value Am and the restart hydraulic pressure value Pm are determined in S3. At this time, the target current value Am is set from the characteristic line 42 at the lower left of FIG. 10, that is, the characteristic line Am2 which is the relationship between the inclination G and the target current value Am. Here, the slope G of the road surface on which the vehicle is stopped at the time of application is G = 21. In this case, the target current value Am is set to A21 from the characteristic line Am2.

The characteristic line Am2 can be set as, for example, a target current value Am that can obtain a minimum pressing force F according to the road surface inclination G. In this case, the characteristic line Am2 has a constant value (first predetermined current value Aa) from 0 to a predetermined angle Ga at which the inclination G becomes a predetermined value, and increases monotonically when the inclination G becomes larger than the predetermined angle Ga (1st predetermined current value Aa). Proportional relationship). That is, the target current value Am becomes larger as the inclination G becomes larger than the predetermined angle Ga. Then, at the maximum inclination G22, for example, the target current value Am = G22 at which the maximum pressing force (full clamping force) F = F22 can be obtained.

Next, the pressing force (target pressing force) F required for the inclination G21 is the characteristic line 41 on the upper left of FIG. 10, that is, the characteristic line Fc2 which is the relationship between the inclination G and the pressing force F required for stopping. It becomes F21. On the other hand, if the maximum value of the target pressing force F is F22 corresponding to the maximum set inclination G22, the difference between F22 and F21, that is, the shortage for the pressing force required at the time of complete parking is ΔFp21. By using this ΔFp21 and the characteristic line 43 at the lower right of FIG. 10, that is, the characteristic line Pm2 which is the relationship between the restart hydraulic pressure value Pm and the pressing pressure increase amount ΔF due to the hydraulic pressure, the restart hydraulic pressure value Pm = P21 can be set. The characteristic line Pm2 is predetermined from the amount of increase in the pressing force remaining when the apply operation is completed while the hydraulic pressure is acting and then the hydraulic pressure is released, as in the first embodiment. Can be done.

After setting the target current value Am and the restart hydraulic pressure value Pm in this way (for example, if Am = A21 and Pm = P21 are set), the electric motor 7A is started to be driven in S5 of FIG. By the process, the electric motor 7A is stopped at the target current value Am = A21. As a result, the pressing force F21 is obtained. Here, when the hydraulic pressure Pa at the time of application completion (at the time of operation completion) is, for example, Pa = P21, the pressing pressure is also added to the hydraulic pressure, so that the total is F23. After that, when the hydraulic pressure is released, the pressing pressure drops to F22 due to elastic deformation of the pressing member holding mechanism 8 and the like. In other words, the pressing pressure F21 increases by ΔFp21 by the hydraulic pressure P21 to become F22.

Therefore, if the hydraulic pressure at the time of the first apply operation is the restart hydraulic pressure value P21 or more, the pressing pressure F22 or more required at the time of complete parking can be obtained. Therefore, reapply, that is, to the maximum target current value A22. It is possible to avoid reapplying. That is, the parking brake control device 24 obtains a pressing force increase amount ΔFp21 corresponding to the difference ΔFp21 between the target pressing force F21 at that time and the target pressing force F22 required for the maximum set inclination G22 by the hydraulic pressure P21 when the application is completed. If it is, do not restart (reapply). As a result, unnecessary restart can be suppressed and power consumption can be reduced.

As described above, in the second embodiment, in S3 of FIG. 4, the target current value Am is the road surface inclination G (for example, G21) in which the vehicle is stopped at the time of application based on the characteristic line 42 at the lower left of FIG. ), The target current value Am (for example, A21) is set so that the minimum pressing force F can be obtained. At this time, the restart hydraulic pressure value Pm is the pressing force F (for example, F21) obtained at the set target current value Am (for example, A21) based on the characteristic line 41 and the characteristic line 43 in FIG. The hydraulic pressure value (for example, P21) is set so that the pressing pressure increase amount ΔF corresponding to the difference ΔF (for example, ΔFp21) from the pressing pressure F22 required for the maximum setting inclination G22 can be obtained. Then, when the pressing pressure increase amount (for example, ΔFp21) corresponding to the difference ΔF is obtained by the hydraulic pressure Pa at the completion of application, it is determined as “YES” by the process of S13 in FIG. As a result, the restart flag F3 remains off, and the restart is suppressed. On the other hand, when the pressing force increase amount (for example, ΔFp21) corresponding to the difference ΔF cannot be obtained due to the hydraulic pressure Pa at the completion of application, it is determined as “NO” by the process of S13 in FIG. The restart flag F3 is turned on. In this case, when it is determined in S23 of FIG. 6 that the vehicle is in a completely parked state, the target current value Am = G22 is set in S24, and reoperation (reapply) is performed.

Thus, in the case of the second embodiment as well, the unnecessary restart (reapply) can be restricted (suppressed) as in the first embodiment.

That is, in the second embodiment, the parking brake control device 24 is determined by the processes of S12 and S13 of FIG. 5 that the hydraulic pressure Pa at the completion of the holding operation is equal to or higher than a predetermined value (restarting hydraulic pressure value). Then, it does not proceed to S15. In this case, the predetermined value (restarting hydraulic pressure value) is, for example, the amount of increase in pressing force ΔFp21 corresponding to the difference between the pressing force F21 obtained at the target current value A21 at the time of application and the pressing force F22 required at the maximum set inclination G22. Can be set as the hydraulic pressure P21 capable of obtaining. Therefore, when the hydraulic pressure when applied on the inclination G21 is equal to or higher than the restart hydraulic pressure value P21, the restart flag F3 is not turned on and the restart is prohibited. At this time, since the pressing force is F22 or higher even if the vehicle is not restarted, the vehicle can be maintained even if the road surface reaches the maximum inclination G22 while the vehicle is stopped.

In other words, the parking brake control device 24 determines the necessity of restarting at the time of complete parking by the processing of S3, S12 and S13 in consideration of the pushing pressure increase amount ΔF due to the hydraulic pressure Pa at the completion of the holding operation. To do. Then, when it is determined that restart is not necessary, that is, the pressing force F obtained at the target current value Am at the time of application and the pressing force F22 required at the maximum set inclination G22 are determined by the hydraulic pressure Pa at the completion of application. When the pressing force increase amount ΔF corresponding to the difference is obtained, the restart is not performed. As a result, unnecessary restart can be suppressed and power consumption can be reduced.

On the other hand, when the hydraulic pressure Pa at the completion of the holding operation is less than a predetermined value (for example, Pa <P21), the parking brake control device 24 is in a completely parked state in which the driver gets off by the process of S23. When it is determined, the electric motor 7A is restarted by the process of S26. At this time, the target current value Am is set to A22 in S24. In this case, the target current value Am can be, for example, the target current value A22 that can obtain a full clamping force. Therefore, when the pressing force is expected to be insufficient (when it is necessary to add the pressing force), the electric motor 7A can be restarted. As a result, the braking force (pushing pressure, thrust) by the electric motor 7A and the pressing member holding mechanism 8 can be secured when the driver is completely parked so as to get off the vehicle.

As described above, in the second embodiment, the target pressing force is changed according to the road surface inclination G in which the vehicle is stopped, based on the characteristic line 42 at the lower left of FIG. As a result, the current consumption for each operation can be suppressed. In addition to this, when the driver is completely parked by the process of S23 in FIG. 6, the vehicle is transported by, for example, a ship by reapplying by maximizing the target pressing force by the process of S24. Even when the road surface slope changes while the vehicle is stopped, the braking force can be maintained (the vehicle can be kept stopped). Further, by the processing of S12 and S13 of FIG. 5, when the hydraulic pressure Pa at the completion of application is high, it is possible to avoid power consumption (energy consumption) due to unnecessary reapply by eliminating the need for reapply. it can.

In the second embodiment, the reapply can be limited to when the driver gets off, that is, when the hydraulic pressure is not acting. Therefore, it is possible to prevent the pressing force of the electric motor 7A from becoming excessive due to the hydraulic pressure at the time of application. That is, it is possible to suppress excessive propulsion of the piston 6D, shorten the time required for subsequently releasing the parking brake, and reduce the power consumption (current consumption) at this time.

In each embodiment, a case where the restart is suppressed based on the hydraulic pressure information at the completion of the holding operation by the electric mechanism has been described as an example. That is, as the "restriction of the operation of the electric motor", the case of suppressing the restart, that is, the case of prohibiting the restart has been described as an example. However, the present invention is not limited to this, and for example, the operation amount of the restart may be changed (smaller) based on the hydraulic pressure information at the completion of the holding operation by the electric mechanism. For example, the restart may be performed with an operation amount smaller than the full reclamp amount based on the hydraulic pressure information at the completion of the holding operation by the electric mechanism. That is, the "restriction of the operation of the electric motor" includes not only prohibiting the restart but also restarting (restarting with an operating amount smaller than the full reclamp amount). Conversely, "restriction of motor operation" means "do not restart with a full reclamp amount", that is, "reactivate with a smaller amount of operation than the full reclamp amount, or perform a restart. Corresponds to "nothing".

In each embodiment, the case where the left and right rear wheel side disc brakes 6 are disc brakes with an electric parking brake function has been described as an example. However, the present invention is not limited to this, and the left and right front wheel side disc brakes 5 may be used as disc brakes with an electric parking brake function. Further, the brakes of all the front wheels and the rear wheels (all four wheels) may be configured by a disc brake having an electric parking brake function. That is, the brakes of at least a pair of wheels of the vehicle can be configured by a disc brake with an electric parking brake function.

In each embodiment, as a parking brake device (electric parking brake mechanism), a hydraulic disc brake 6 with an electric parking brake has been described as an example. However, the brake mechanism is not limited to the disc brake type, and may be configured as a drum brake type brake mechanism. Further, various brake mechanisms can be adopted, such as a drum-in disc brake provided with a drum type electric parking brake on the disc brake, and a configuration in which the parking brake is held by pulling a cable with an electric motor.

That is, the present invention can be applied to an electric brake device in which two pressing forces, a hydraulic mechanism (cylinder mechanism) as a regular brake and an electric mechanism as a parking brake, are applied to a brake pad or a brake shoe. Therefore, in addition to the hydraulic disc brake with an electric parking brake given as an example of the embodiment, for example, a disc brake or a drum brake with a parking brake mechanism according to a conventional technique and an electric motor that pulls a cable attached to the parking brake mechanism. It can also be applied to an electric braking device combined with a mechanism.

Further, it is needless to say that each embodiment is an example, and partial replacement or combination of the configurations shown in different embodiments is possible.

As the electric brake device based on the embodiment described above, for example, the one described below can be considered.

As the first aspect, a mechanism that moves by hydraulic pressure to press the braking member against the braked member and an electric mechanism that operates the electric motor in the direction of pressing the braking member against the braked member to maintain the braking state. A control device that controls the operation of the electric motor, stops the operation of the electric motor when the holding operation by the electric mechanism is completed, and then operates the electric motor in a direction of pressing the braking member against the braked member. In the electric brake device including, the control device operates the electric motor in a direction of pressing the braking member against the braked member based on hydraulic pressure information to the piston when the holding operation by the electric mechanism is completed. Limit that.

According to this first aspect, in order to limit the operation of the motor after the operation of the motor is stopped based on the hydraulic pressure information to the piston at the completion of the holding operation, an increase in the pressing force due to the hydraulic pressure is considered. Therefore, it is possible to determine whether or not the electric motor needs to be operated thereafter. As a result, unnecessary restart can be suppressed and power consumption can be reduced. Further, the operating amount when operating the electric motor after that may be changed (smaller) in consideration of the increase in the pressing force due to the hydraulic pressure. In this case as well, the amount of operation can be reduced, so that the power consumption can be reduced.

In the second aspect, in the first aspect, when the hydraulic pressure at the completion of the holding operation by the electric mechanism is equal to or higher than a predetermined value, the control device presses the braking member against the braked member. The operation of the electric motor is restricted to.

According to this second aspect, when the hydraulic pressure at the completion of the holding operation is equal to or higher than a predetermined value, the hydraulic pressure is equal to or higher than the predetermined value in order to limit the operation of the motor after the operation of the motor is stopped. Whether or not it is necessary to operate the electric motor after that can be determined. As a result, unnecessary restart can be suppressed and power consumption can be reduced. Further, the operating amount when operating the electric motor after that may be changed (smaller) depending on whether or not the hydraulic pressure is equal to or higher than a predetermined value. In this case as well, the amount of operation can be reduced, so that the power consumption can be reduced.

As a third aspect, in the first aspect, when the hydraulic pressure at the completion of the holding operation by the electric mechanism is less than a predetermined value, the control device of the braking member after the holding operation of the electric mechanism is completed. When the temperature becomes lower than the predetermined temperature, or when a predetermined time elapses after the holding operation of the electric mechanism is completed, the electric motor is operated in the direction of pressing the braking member against the braked member.

According to this third aspect, when it is necessary to add the pressing force (that is, when the pressing force is expected to be insufficient), the electric motor can be operated, and the braking force (pressing force, thrust) by the electric mechanism can be operated. ) Can be secured.

4 Disc rotor (braked member)
6 Rear wheel side disc brake (electric brake device)
6B caliper (cylinder mechanism)
6C Brake pad (braking member)
6D piston (cylinder mechanism)
7A electric motor (electric motor, electric mechanism)
8 Pressing member holding mechanism (electric mechanism)
21 W / C pressure sensor 22 M / C pressure sensor 24 Parking brake control device (control device)

Claims (2)

A cylinder mechanism having a piston that moves by hydraulic pressure and presses the braking member against the braking member,
An electric mechanism by an electric motor to move the piston, and presses the braking member to the braked member, to hold the braking state,
The controls operation of the electric motor, the complete holding operation by the electric mechanism, after stopping the operation of the electric motor, and a control device for re-operating the motor and the brake member in a direction of pressing the the braked member, In the electric brake device equipped with
The control device prohibits restarting the electric motor in the direction of pressing the braking member against the braked member when the hydraulic pressure on the piston at the completion of the holding operation by the electric mechanism is equal to or higher than a predetermined value. An electric braking device characterized by In claim 1,
In the control device, when the hydraulic pressure at the completion of the holding operation by the electric mechanism is less than a predetermined value, the temperature of the braking member becomes lower than the predetermined temperature after the holding operation of the electric mechanism is completed, or the electric mechanism An electric braking device characterized in that the electric motor is reactivated in a direction of pressing the braking member against the braked member when a predetermined time has elapsed from the completion of the holding operation of the brake member.

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