JP2015182651A - Vehicular brake device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vehicular brake device capable of generating proper friction brake force.SOLUTION: A vehicular brake device comprises: a master cylinder 11 for generating master pressure according to operation force of a driver which is inputted to a brake pedal 71 in master chambers 10a, 10b; a differential pressure control valve 536 for maintaining wheel cylinder pressure for control differential pressure according to current to be higher than the master pressure; a compression amount calculation part 6 for calculating a compression amount Pp based on execution regenerative brake force BF generated by a regenerative brake device A and brake stroke Bs detected by a brake sensor 72; a liquid pressure control part 6 for controlling current which is supplied to the differential pressure control valve 536 for compressing the wheel cylinder pressure by the compression amount Pp with respect to the master pressure; and a compression amount correction part 6 for adding liquid pressure corresponding to an execution regenerative brake force reduction amount ΔBFr as a correction amount C to the compression amount Pp when sharing of the friction brake force from the regenerative brake force is executed.

Description

  The present invention relates to a vehicle braking device that controls a braking force applied to a vehicle.

  As an example of a vehicle braking device that controls a braking force applied to a vehicle, a vehicle braking device disclosed in Patent Document 1 is known. This vehicle braking device includes a master cylinder that generates a master cylinder pressure in a master chamber by a driver's operation of a brake pedal, a friction braking device that includes a wheel cylinder, and a wheel differential pressure that corresponds to a control differential pressure corresponding to a supplied current. And a pump that pressurizes the wheel cylinder pressure by discharging brake fluid to the wheel cylinder.

  Such a vehicle braking device is mounted on a vehicle including a regenerative braking device that generates a regenerative braking force, and realizes regenerative cooperative control. In other words, the regenerative braking force varies depending on the vehicle speed and the state of charge of the battery, but the differential pressure control valve adjusts the wheel cylinder pressure so that the sum of the friction braking force and the regenerative braking force becomes the target braking force. The braking force is adjusted.

  In the vehicle braking device disclosed in Patent Document 1, a target braking force is calculated based on the stroke of the brake pedal detected by the stroke sensor, and the friction braking force based on the master pressure detected by the master pressure sensor is calculated from the target braking force. The control braking force is calculated by subtracting. The control braking force is a braking force that can be controlled by the vehicle braking device. The braking force excluding the friction braking force due to the master pressure out of the total braking force, that is, the friction braking force due to pump pressurization and the regenerative braking. This is the total power. Next, the regenerative braking force that can be generated by the regenerative braking device is subtracted from the control braking force to calculate a friction braking force (hereinafter, abbreviated as a pressurization amount as appropriate) by pump pressurization. Then, the differential pressure control valve is controlled so that the calculated friction braking force by the pump pressurization is generated in the friction braking device.

JP2013-71520A

  The master pressure varies depending on the operation of the brake pedal by the driver. In the vehicle braking apparatus disclosed in Patent Document 1, as described above, the control braking force is calculated by subtracting the friction braking force based on the master pressure detected by the master pressure sensor from the target braking force. For this reason, the control braking force changes due to the change in the master pressure, and as a result, the friction braking force (pressurization amount) due to pump pressurization also changes. When the friction braking force due to the pump pressurization changes, the brake fluid flows between the wheel cylinder and the master chamber by the operation of the differential pressure control valve, and as a result, the master pressure changes. For this reason, when the driver suddenly operates the brake pedal and the master pressure changes suddenly, the pressurization amount also changes suddenly, the master pressure changes as the pressurization amount changes suddenly, and the master pressure repeatedly increases and decreases. There was a possibility that a hunting phenomenon would occur. Thus, when the master pressure repeatedly increases and decreases, the friction braking force also repeatedly increases and decreases.

  In order to solve such a problem, the control braking force is calculated based only on the brake pedal stroke detected by the stroke sensor, not by the master pressure detected by the master pressure sensor, and then by pump pressurization. A method in which the friction braking force (pressurization amount) is calculated is conceivable.

  When the regenerative braking force is switched from the regenerative braking force to the friction braking force by pressurizing the pump due to deceleration of the vehicle speed, the hydraulic pressure component that generates the same friction braking force as the absolute value of the reduction amount of the regenerative braking force is the differential pressure. The control valve is pressurized, and control is performed to prevent the total braking force from decreasing. However, if the brake fluid flows from the master chamber to the wheel cylinder side as the amount of pressurization increases, the master pressure decreases, the friction braking force decreases as the master pressure decreases, and the total braking force decreases. Problems arise.

  This invention is made | formed in view of such a situation, and it aims at providing the braking device for vehicles which can generate | occur | produce an appropriate friction braking force.

  In order to solve the above-described problem, the invention of the vehicle braking device according to claim 1 includes an input member to which an operation force of a driver is input, and an operation amount detection unit that detects an operation amount of the input member. And a friction braking device that generates a friction braking force by the wheel cylinder pressure input to the wheel cylinder, and a master chamber connected to the wheel cylinder are formed, and the driver's operating force input to the input member is A master cylinder that generates a corresponding master pressure in the master chamber, and a flow path between the master chamber and the wheel cylinder. When energized, the wheel cylinder pressure is controlled by the control differential pressure corresponding to the current. A differential pressure control valve that maintains a state higher than the pressure, a regenerative braking device that generates regenerative braking force, the operation amount detected by the operation amount detection unit, and the regenerative braking device The wheel cylinder pressure is controlled with respect to the master pressure by controlling a current supplied to the differential pressure control valve and a pressurization amount calculation unit that calculates a pressurization amount based on the regenerative braking force being generated. Correction that increases the pressurization amount based on the decrease amount of the regenerative braking force when the fluid pressure control unit that pressurizes the pressurization amount and the replacement of the frictional braking force from the regenerative braking force are executed. And a pressurizing amount correction unit to be performed.

  According to the configuration of the vehicle braking device described above, the pressurization amount calculation unit calculates the pressurization amount based on the operation amount detected by the operation amount detection unit and the regenerative braking force generated by the regenerative braking device. . In this way, since the pressurization amount is calculated regardless of the master pressure, the pressurization amount does not change due to the change in the master pressure, the control differential pressure by the differential pressure control valve does not change, and the difference Since the brake fluid does not flow between the pressure control valve and the master chamber, the master pressure also does not change. For this reason, the occurrence of a hunting phenomenon in which the master pressure repeatedly increases and decreases due to a sudden change in the master pressure is prevented.

  The pressurization amount correction unit performs correction to increase the pressurization amount based on the decrease amount of the regenerative braking force when the replacement of the regenerative braking force with the friction braking force is performed. Thereby, even if the amount of pressurization increases by switching from the regenerative braking force to the friction braking force by pump pressurization and the master pressure decreases, the amount of pressurization is increased based on the amount of decrease in the regenerative braking force. Correction is performed, and a reduction in friction braking force is prevented. In this way, it is possible to provide a vehicle braking device that can generate an appropriate friction braking force.

It is a schematic diagram showing one embodiment of a hybrid vehicle on which the friction braking unit of this embodiment is mounted. It is a fragmentary sectional view showing the composition of the friction braking unit of this embodiment. It is an enlarged view of a spool piston and a spool cylinder at the time of “decompression mode”. It is a graph showing an example of the relationship between a brake stroke and braking force. FIG. 4 is an enlarged view of a spool piston and a spool cylinder in a “pressure increasing mode”. It is an enlarged view of a spool piston and a spool cylinder at the time of “holding mode”. It is detail drawing of a hydro booster rear part. It is a time chart showing the relationship between elapsed time, vehicle speed, and braking force in the vehicle braking device of the comparative example. 4 is a time chart showing the relationship between elapsed time, vehicle speed, effective regenerative braking force, friction braking force due to pump pressurization, and friction braking force due to master pressure in the vehicle braking apparatus of the present embodiment. It is a flowchart of a braking control process. It is a flowchart of a pressurization amount correction process.

(Hybrid vehicle)
Hereinafter, embodiments of the present invention will be described with reference to the drawings. As shown in FIG. 1, a hybrid vehicle (hereinafter simply referred to as a vehicle) on which a friction braking unit B (vehicle braking device) according to the present embodiment is mounted drives driving wheels such as left and right front wheels Wfl and Wfr. Vehicle. The vehicle includes a brake ECU 6, an engine ECU 8, a hybrid ECU 9, a hydro booster 10, a pressure regulator 53, a hydraulic pressure generator 60, a brake pedal 71, a brake sensor 72, an engine 501, a motor 502, a power split mechanism 503, and a power transmission mechanism 504. And an inverter 506 and a battery 507.

  Note that the friction braking unit B of the present embodiment mainly includes a brake ECU 6, a hydro booster 10, a pressure regulator 53, a hydraulic pressure generator 60, a brake pedal 71, and a brake sensor 72.

  The brake ECU 6 controls the friction braking unit B. The brake ECU 6 has a CPU, a RAM, a storage unit, and a bus that connects them. The CPU executes a program corresponding to the flowcharts shown in FIGS. The RAM temporarily stores variables necessary for executing the program. The storage unit is configured by a nonvolatile memory or the like and stores the program. The brake ECU 6 constitutes a “pressurization amount calculation unit”, “hydraulic pressure control unit”, “pressurization amount correction unit”, and “storage unit” described in the claims.

  The driving force of the engine 501 is transmitted to the drive wheels Wfl and Wfr via the power split mechanism 503 and the power transmission mechanism 504. The driving force of the motor 502 is transmitted to the drive wheels Wfl and Wfr via the power transmission mechanism 504.

  The inverter 506 converts voltage between the motor 502 and the generator 505 and a battery 507 as a DC power source. The engine ECU 8 adjusts the driving force of the engine 501 based on a command from the hybrid ECU 9. The hybrid ECU 9 controls the motor 502 and the generator 505 through the inverter 506. The hybrid ECU 9 is connected to a battery 507 and monitors the charging state, charging current, and the like of the battery 507. The hybrid ECU 9 controls the inverter 506 so that the regenerative braking force generated by the generator 505 and applied to the wheels Wfl and Wfr becomes an “execution regenerative braking force” described later. The above-described generator 505, inverter 506, and battery 507 constitute a regenerative braking device A. In the embodiment shown in FIG. 1, the motor 502 and the generator 505 are separate bodies, but a motor generator in which the motor and the generator are integrated may be used.

  At positions adjacent to each wheel Wfl, Wfr, Wrl, Wrr, there are brake discs DRfl, DRfr, DRrl, DRrr that rotate integrally with each wheel Wfl, Wfr, Wrl, Wrr, and brake discs DRfl, DRfr, DRrl, DRrr. Friction braking devices Bfl, Bfr, Brl, and Brr that press a brake pad (not shown) to generate a friction braking force are provided. The friction braking devices Bfl, Bfr, Brl, Brr include wheel cylinders WCfl that press the brake pads against the brake discs DRfl, DRfr, DRrl, DRrr by a master pressure generated by a hydro booster 10 (shown in FIG. 2) described later. WCfr, WCrl, WCrr are provided.

  Wheel speed sensors Sfl, Sfr, Srl, Srr are provided at positions adjacent to the respective wheels Wfl, Wfr, Wrl, Wrr. The wheel speed sensors Sfl, Sfr, Srl, Srr output a pulse signal having a frequency corresponding to the rotation of each wheel Wfl, Wfr, Wrl, Wrr to the hybrid ECU 9 and the brake ECU 6. The hybrid ECU 9 and the brake ECU 6 calculate the vehicle speed V based on signals from the wheel speed sensors Sfl, Sfr, Srl, Srr.

  The brake sensor 72 detects an operation amount of the brake pedal 71 (hereinafter abbreviated as a brake stroke Bs) and outputs a detection signal to the brake ECU 6.

(Hydraulic pressure generator)
Next, the hydraulic pressure generator 60 will be described with reference to FIG. The hydraulic pressure generator 60 generates an accumulator pressure. The hydraulic pressure generator 60 includes an accumulator 61, a hydraulic pump 62, a motor 63, and an accumulator pressure sensor 65.

  The accumulator 61 accumulates the accumulator pressure that is the hydraulic pressure of the brake fluid generated by the hydraulic pump 62. The accumulator 61 is connected to the accumulator pressure sensor 65 and the hydraulic pump 62 by a flow channel 66. The hydraulic pump 62 is connected to the reservoir 19. The hydraulic pump 62 is driven by the motor 63 to supply the brake fluid stored in the reservoir 19 to the accumulator 61.

  The accumulator pressure sensor 65 detects an accumulator pressure that is a fluid pressure in the accumulator 61. When the accumulator pressure sensor 65 detects that the accumulator pressure has dropped below a predetermined value, the motor 63 is driven based on a control signal from the brake ECU 6.

(Hydro Booster)
Below, the hydro booster 10 is demonstrated using FIG. The hydro booster 10 adjusts the accumulator pressure generated by the hydraulic pressure generator 60 according to the operation of the brake pedal 71 to generate a servo pressure, and generates a master pressure Pm from the servo pressure.

  The hydro booster 10 includes a master cylinder 11, a fail cylinder 12, a first master piston 13, a second master piston 14, an input piston 15, an operating rod 16, a first return spring 17, a second return spring 18, a reservoir 19, and a stopper member 21. , Mechanical relief valve 22, spool piston 23, spool cylinder 24, spool spring 25, simulator spring 26, pedal return spring 27, swing member 28, first spring receiver 29, second spring receiver 30, connection member 31, moving member 32, holding piston 33, simulator rubber 34, receiving member 35, fail spring 36, buffer member 37, first spool spring receiving 38, second spool spring receiving 39, pressing member 40, and seal portion And has a 41 to 49.

  The side on which the first master piston 13 is provided is the front of the hydro booster 10, and the side on which the operating rod 16 is provided is the rear of the hydro booster 10. That is, the axial direction of the hydro booster 10 (master cylinder 11) is the front-rear direction.

  The master cylinder 11 has a bottom 11a at the front end and has a bottomed cylindrical shape that opens rearward. In other words, the master cylinder 11 has a cylindrical space 11p in the front-rear direction. The master cylinder 11 is attached to the vehicle. The master cylinder 11 has a first port 11b, a second port 11c, a third port 11d, a fourth port 11e, a fifth port 11f (supply port), communicating in the space 11p in order from the front to the rear. A sixth port 11g and a seventh port 11h are formed. The second port 11c, the fourth port 11e, the sixth port 11g, and the seventh port 11h are each connected to a reservoir 19 that stores brake fluid. That is, the reservoir 19 is connected to the space 11p of the master cylinder 11.

  Before and after the position where the second port 11c on the inner peripheral surface of the master cylinder 11 is provided, seal members 41 and 42 that contact the outer peripheral surface of the first master piston 13 (described later) over the entire periphery are provided. It has been. In addition, before and after the position where the fourth port 11e is provided on the inner peripheral surface of the master cylinder 11, seal members 43 and 44 that are in contact with the outer peripheral surface of the second master piston 14 (described later) over the entire periphery, respectively. Is provided.

  Further, before and after the position where the fifth port 11f on the inner peripheral surface of the master cylinder 11 is provided, respectively, a first cylinder portion 12b and a second cylinder portion 12c of the fail cylinder 12 which will be described later extend over the entire circumference. Sealing members 45 and 46 that come into contact with each other are provided. In addition, before and after the position where the seventh port 11h on the inner peripheral surface of the master cylinder 11 is provided, seal members 48 and 49 that are in contact with the second cylinder portion 12c of the fail cylinder 12 over the entire circumference, respectively. Is provided.

  A support member 59 is provided in front of the seal member 45. The seal member 45 and the support member 59 are held in the same holding recess 11j that is recessed in the master cylinder 11, and are in contact with each other (shown in FIG. 3). The support member 59 is a split ring. The support member 59 is formed with a slit. The support member 59 is made of an elastic material such as resin. As shown in FIG. 3, the inner peripheral surface of the support member 59 is in contact with the outer peripheral surface of a first cylinder portion 12 b of the fail cylinder 12 described later.

  As shown in FIG. 2, the fifth port 11 f (supply port) communicates with the outer peripheral surface of the master cylinder 11 and the space 11 p. The fifth port 11 f is connected to the accumulator 61 by a flow path 67. That is, the accumulator 61 is connected to the space 11p of the master cylinder 11, and the accumulator pressure is supplied to the fifth port 11f.

  The fifth port 11f and the sixth port 11g communicate with each other through a communication channel 11k. A mechanical relief valve 22 is provided in the communication channel 11k. The mechanical relief valve 22 prevents the flow of brake fluid from the sixth port 11g to the fifth port 11f, and when the fifth port 11f becomes equal to or higher than the specified pressure, the fifth port f changes to the sixth port 11g. Allow distribution of brake fluid.

  The first master piston 13 is provided in front of the space 11p of the master cylinder 11 (behind the bottom portion 11a) so as to be slidable in the front-rear direction. The first master piston 13 has a bottomed cylindrical shape composed of a cylindrical cylindrical portion 13a and a receiving portion 13b formed so as to close the cylindrical portion 13a behind the cylindrical portion 13a. A circulation hole 13c is formed in the cylindrical portion 13a. In addition, in the front side of the receiving part 13b, the 1st master chamber 10a is formed of the space enclosed by the internal peripheral surface of the master cylinder 11, the cylinder part 13a, and the receiving part 13b. The first port 11b communicates with the first master chamber 10a.

  A first return spring 17 is provided between the bottom portion 11 a of the master cylinder 11 and the receiving portion 13 b of the first master piston 13. When the first master piston 13 is urged rearward by the first return spring 17 and the brake pedal 71 is not depressed, the first master piston 13 returns to the original position shown in FIG. ing.

  In the state where the first master piston 13 is located at the original position, the second port 11c and the flow hole 13c are matched, and the reservoir 19 and the first master chamber 10a are in communication. For this reason, brake fluid is supplied from the reservoir 19 to the first master chamber 10 a, and surplus brake fluid in the first master chamber 10 a is returned to the reservoir 19. When the first master piston 13 moves forward from the original position, the second port 11c is blocked by the cylindrical portion 13a, the first master chamber 10a is sealed, and the master pressure Pm can be generated in the first master chamber 10a. It becomes.

  The second master piston 14 is provided behind the first master piston 13 in the space 11p of the master cylinder 11 so as to be slidable in the front-rear direction. The second master piston 14 includes a cylindrical first tube portion 14a formed at a front portion thereof, a cylindrical second tube portion 14b formed at the rear of the first tube portion 14a, and a first tube portion 14a. And a receiving portion 14c formed so as to close the first cylindrical portion 14a and the second cylindrical portion 14b at the connecting portion of the second cylindrical portion 14b. A flow hole 14d is formed in the first cylinder portion 14a.

  A second master chamber 10b is formed in front of the receiving portion 14c by a space surrounded by the receiving portion 13b, the inner peripheral surface of the master cylinder 11, the first cylindrical portion 14a, and the receiving portion 14c. The third port 11d communicates with the second master chamber 10b.

  Between the receiving part 13b of the first master piston 13 and the receiving part 14c, a second return spring 18 having a larger set load than the first return spring 17 is provided. When the second master piston 14 is urged rearward by the second return spring 18 and the brake pedal 71 is not depressed, the second master piston 14 returns to the original position shown in FIG. ing.

  In a state where the second master piston 14 is located at the original position, the fourth port 11e and the flow hole 14d are matched, and the reservoir 19 and the second master chamber 10b are in communication. For this reason, brake fluid is supplied from the reservoir 19 to the second master chamber 10 b, and surplus brake fluid in the second master chamber 10 b is returned to the reservoir 19. When the second master piston 14 moves forward from the original position, the fourth port 11e is blocked by the cylindrical portion 14a, the second master chamber 10b is sealed, and the master pressure Pm can be generated in the second master chamber 10b. It becomes.

  The fail cylinder 12 is provided behind the second master piston 14 in the space 11p of the master cylinder 11 so as to be slidable in the front-rear direction. In the fail cylinder 12, a front end cylindrical portion 12a, a first cylindrical portion 12b, and a second cylindrical portion 12c are integrally formed coaxially from the front to the rear. All of the tip cylinder part 12a, the first cylinder part 12b, and the second cylinder part 12c are cylindrical. The outer diameter a of the front end cylinder part 12a, the outer diameter b of the first cylinder part 12b, and the outer diameter c of the second cylinder part 12c increase in this order. A stepped surface 12i is formed between the tip tube portion 12a and the first tube portion 12b.

  At the rear end of the second cylindrical portion 12c, a flange-like contact portion 12h is formed extending outward. The abutting portion 12 h abuts on a stopper member 21 described later so that the fail cylinder 12 does not fall off the master cylinder 11. The inner peripheral surface of the rear portion of the second cylindrical portion 12c has a larger inner diameter than other portions, and a step surface 12j is formed.

  The distal end cylinder part 12 a is inserted into the second cylinder part 14 b of the second master piston 14. A first inner port 12d that communicates from the outer peripheral surface of the first cylindrical portion 12b to the inner peripheral surface is formed at the rear portion of the first cylindrical portion 12b. A second inner port 12e and a third inner port 12f are formed at the front portion of the second cylindrical portion 12c, and communicate with the inner peripheral surface from the outer peripheral surface of the second cylindrical portion 12c. The middle part of the second cylinder part 12c communicates the outer peripheral surface and the inner peripheral surface of the second cylinder part 12c, and a fourth inner port 12g that opens toward the front of the input piston 15 provided in the fail cylinder 12. Is formed

  As shown in FIG. 3, a stopper 12m is formed to project from the front portion of the inner periphery of the second cylinder portion 12c. A channel 12n is formed in communication with the stopper 12m in the front-rear direction.

  As shown in FIG. 2, the input piston 15 is disposed in the front-rear direction inside the rear portion of the second cylinder portion 12 c of the fail cylinder 12 (inside the space 11 p of the master cylinder 11) behind a spool cylinder 24 and a spool piston 23 described later. It is slidably provided. The input piston 15 has a substantially cylindrical shape having a circular cross section. At the rear end of the input piston 15, a rod receiving portion 15 a having a conical recess at the bottom is formed. A spring receiving portion 15 b is recessed in the front portion of the input piston 15. The rear portion of the input piston 15 has a smaller outer diameter than other portions, and a step surface 15e is formed.

  Seal holding recesses 15 c and 15 d are formed in the outer peripheral surface of the input piston 15. Seal members 55 and 56 that are in contact with the inner peripheral surface of the second cylinder portion 12c of the fail cylinder 12 over the entire circumference are attached to the seal holding recesses 15c and 15d.

  The input piston 15 is connected to the brake pedal 71 via the operating rod 16 and the connecting member 31. Therefore, the operating force from the brake pedal 71 is transmitted to the input piston 15 via the connecting member 31 and the operating rod 16. The input piston 15 transmits the transmitted operation force to the spool piston 23 via the simulator spring 26, the moving member 32, the simulator rubber 34, the holding piston 33, and the buffer member 37 to drive the spool piston 23. To do.

  As shown in FIG. 7, the receiving member 35 includes a cylindrical portion 35a and a ring-shaped receiving portion 35b extending inward from the front end of the cylindrical portion 35a. The receiving member 35 is provided at the rear end portion inside the second cylindrical portion 12c such that the front end surface of the receiving portion 35b contacts the stepped surface 12j of the second cylindrical portion 12c and the stepped surface 15e of the input piston 15. Yes.

  The stopper member 21 is slidably provided at the rear part inside the master cylinder 11. The stopper member 21 includes a ring-shaped base portion 21a, a cylindrical cylindrical portion 21b protruding forward from the front surface of the base portion, and a ring-shaped stopper portion 21c extending inward from the front end of the cylindrical portion 21b. .

  A receiving surface 21d is formed on the front surface of the base portion 21a inside the cylindrical portion 21b. The contact portion 12h of the fail cylinder 12 is in contact with the receiving surface 21d. A holding recess 21f that is recessed in a ring shape is formed inside the receiving surface 21d on the front surface of the base 21a. The rear end of the cylindrical portion 35a of the receiving member 35 is inserted into the holding recess 21f. A protruding portion 21g protruding forward in a ring shape is formed inside the holding recess 21f on the front surface of the base portion 21a.

  A receiving hole 21e having a concave shape in a spherical shape is formed at the center of the rear end surface of the base portion 21a. A C ring 86 is attached to the rear end of the master cylinder 11, that is, the opening of the master cylinder 11. The C ring 86 prevents the stopper member 21 from falling off the master cylinder 11.

  The swing member 28 has a ring shape. A spherical pressing surface 28a that matches the receiving hole 21e is formed in the front portion of the swing member 28. The pressing surface 28a is in close contact with the receiving hole 21e, and the swinging member 28 is provided behind the stopper member 21. The swing member 28 can swing with respect to the stopper member 21.

  The fail spring 36 is provided between the receiving portion 35 b of the receiving member 35 and the protruding portion 21 g of the stopper member 21 in the cylindrical portion 35 a of the receiving member 35. In the present embodiment, the fail spring 36 is a plurality of diaphragm springs. With such a configuration, the fail spring 36 biases the fail cylinder 12 forward with respect to the master cylinder 11.

  The first spring receiver 29 is composed of a cylindrical portion 29a and a flange-shaped flange portion 29b formed to extend inward and outward at the front end of the cylindrical portion 29a. The flange portion 29 b is in close contact with the rear end surface of the swing member 28, and the first spring receiver 29 is provided behind the swing member 28.

  A spherical pressing portion 16 a is formed at the front end of the operating rod 16. A screw portion 16 b is formed at the rear end of the operating rod 16. The pressing portion 16a is inserted through the rod receiving portion 15a, and the operating rod 16 is connected to the rear end of the input piston 15. The longitudinal direction of the operating rod 16 is the front-rear direction. The operating rod 16 is inserted through the swing member 28 and the first spring receiver 29.

  The second spring receiver 30 is provided behind the first spring receiver 29 so as to face the first spring receiver 29. The second spring receiver 30 has a bottomed cylindrical shape composed of a bottom portion 30a formed at the rear end thereof and a cylindrical portion 30b formed forward from the bottom portion 30a. A screw hole 30c is formed in the bottom 30a. The screw portion 16b of the operating rod 16 is screwed into the screw hole 30c.

  The pedal return spring 27 is provided between the flange portion 29 b of the first spring receiver 29 and the bottom portion 30 a of the second spring receiver 30. The pedal return spring 27 is held inside the cylindrical portion 29 a of the first spring receiver 29 and the cylindrical portion 30 b of the second spring receiver 30.

  A screw hole 31 a is formed at the front end of the connecting member 31. The threaded portion 16b of the operating rod 16 is screwed into the screw hole 31a, and the connecting member 31 is connected to the rear end of the operating rod 16. The bottom portion 30 a of the second spring receiver 30 is in contact with the front end of the connecting member 31. A shaft hole 31 b is formed in communication with the intermediate portion of the connecting member 31 in the front-rear direction. The screw hole 30 c of the second spring receiver 30 and the screw hole 31 a of the connecting member 31 are screwed to the screw portion 16 b of the operating rod 16. With such a structure, the front-rear direction position of the connecting member 31 with respect to the operating rod 16 can be adjusted.

  The brake pedal 71 is a lever-like member to which the driver's pedaling force (operation force) is transmitted. A shaft hole 71 a is formed in an intermediate portion of the brake pedal 71. A mounting hole 71 b is formed at the upper end of the brake pedal 71. A bolt 81 is inserted into the mounting hole 71b, and the brake pedal 71 is swingably mounted on a mounting portion (a chain line shown in FIG. 2) with the mounting hole 71b as a swing center. A connecting pin 82 is inserted into the shaft hole 71 a and the shaft hole 31 b of the connecting member 31, and the brake pedal 71 is swingably connected to the connecting member 31. Due to the urging force of the pedal return spring 27, the second spring receiver 30 and the connecting member 31 are urged rearward, and the brake pedal 71 returns to the original position shown in FIG.

  As shown in FIG. 2, the holding piston 33 is provided to be slidable in the front-rear direction in the front of the second cylinder portion 12 c of the fail cylinder 12 (in the space 11 p of the master cylinder 11). The holding piston 33 has a bottomed cylindrical shape composed of a bottom 33a formed at the front thereof and a cylinder 33b formed at the rear of the bottom 33a. A holding recess 33c is formed in the front end surface of the bottom 33a. A seal holding recess 33d is formed in the outer peripheral surface of the cylindrical portion 33b. A seal member 75 that is in contact with the inner peripheral surface of the second cylinder 12c of the fail cylinder 12 over the entire circumference is attached to the seal holding recess 33d. As shown in FIG. 3, a C-ring 85 is attached to the inner peripheral surface of the second cylindrical portion 12c. The rear end of the holding piston 33 comes into contact with the C-ring 85 and the holding piston 33 is prevented from sliding backward.

  As shown in FIG. 2, the moving member 32 is slidable in the front-rear direction behind the holding piston 33 (spool piston 23) in the second cylinder portion 12c of the fail cylinder 12 (in the space 11p of the master cylinder 11). Is provided. The moving member 32 includes a flange-shaped flange portion 32a formed at the front end portion thereof, and a shaft portion 32b formed at the rear of the flange portion 32a.

  A rubber receiving recess 32c is formed in the front end surface of the flange portion 32a. A cylindrical simulator rubber 34 is attached to the rubber receiving recess 32c. The simulator rubber 34 protrudes forward from the flange portion 32a. In the original position, the simulator rubber 34 (moving member 32) is separated from the holding piston 33 (spool piston 23).

  The flange portion 32a is formed with a flow path 32h that communicates a space formed between the front of the flange portion 32a and the holding piston 33 and a simulator chamber 10f described later. For this reason, when the moving member 32 slides with respect to the holding piston 33, the brake fluid flows between the space and the simulator chamber 10f, and the sliding of the moving member 32 with respect to the holding piston 33 is not hindered.

  A simulator chamber 10 f is formed by a space surrounded by the second cylinder portion 12 c of the fail cylinder 12, the holding piston 33, and the input piston 15. The brake fluid is filled in the simulator room 10f.

  The simulator spring 26 is provided between the flange portion 32a of the moving member 32 and the spring receiving portion 15b of the input piston 15 in the simulator chamber 10f. That is, the simulator spring 26 is provided in front of the input piston 15 in the second cylinder portion 12c of the fail cylinder 12 (in the space 11p of the master cylinder 11). The shaft portion 32b of the moving member 32 is inserted into the simulator spring 26, and the simulator spring 26 is held by the shaft portion 32b. In the present embodiment, the front portion of the simulator spring 26 is press-fitted into the shaft portion 32 b of the moving member 32. With such a configuration, when the input piston 15 further moves forward from the state in which the simulator rubber 34 (moving member 32) is in contact with the holding piston 33, the input piston 15 is urged rearward by the simulator spring 26. The operating force of the driver is input to the moving member 32 via the brake pedal 71, the connecting member 31, the operating rod 16, the input piston 15, and the simulator spring 26.

  The fifth port 11 f opens toward the outer peripheral surface of the first cylinder portion 12 b of the fail cylinder 12. As described above, the outer diameter c of the second cylindrical portion 12c is larger than the outer diameter b of the first cylindrical portion 12b. For this reason, when the accumulator pressure acts on the fifth port 11f, the backward force acts on the fail cylinder 12 due to the accumulator pressure and the cross-sectional area difference between the first cylinder portion 12b and the second cylinder portion 12c. The member 21 is pressed against the member 21, and the fail cylinder 12 is located at the original position at the end of the sliding range.

  In a state where the fail cylinder 12 is in the original position, the fourth inner port 12 g communicates with the seventh port 11 h of the master cylinder 11. As described above, the simulator chamber 10f and the reservoir 19 communicate with each other through the “reservoir flow path” including the fourth inner port 12g and the seventh port 11h, and as the input piston 15 slides in the front-rear direction, the simulator chamber 10f When the volume changes, the brake fluid in the simulator chamber 10f is returned to the reservoir 19, or the brake fluid is supplied from the reservoir 19 to the simulator chamber 10f. For this reason, sliding in the front-rear direction of the input piston 15 is not hindered.

  As shown in FIG. 3, the spool cylinder 24 is fixed behind the second master piston 14 in the first cylinder portion 12 b of the fail cylinder 12 (in the space 11 p of the master cylinder 11). The spool cylinder 24 has a cylindrical shape. Seal holding recesses 24 a and 24 b are formed in the outer peripheral surface of the spool cylinder 24. Seal members 57 and 58 that are in contact with the inner peripheral surface of the first cylindrical portion 12b over the entire circumference are held in the seal holding recesses 24a and 24b. The forward movement of the spool cylinder 24 relative to the first cylinder portion 12b is prevented by the frictional force between the seal members 57 and 58 and the inner peripheral surface of the first cylinder portion 12b. The rear end of the spool cylinder 24 abuts against the stopper 12m, and the backward movement of the spool cylinder 24 is prevented.

  The spool cylinder 24 is formed with a spool port 24 c that communicates the outer peripheral surface and the inner peripheral surface of the spool cylinder 24. The spool port 24c communicates with the first inner port 12d. On the inner peripheral surface of the spool cylinder 24 behind the spool port 24c, a first spool recess 24d is formed to be recessed over the entire periphery. On the inner peripheral surface of the spool cylinder 24 rearward of the first spool recess 24d, a second spool recess 24f is formed to be recessed over the entire circumference.

  On the outer peripheral surface of the spool cylinder 24 behind the seal holding recess 24b, a circulation recess 24e is formed to be recessed over the entire periphery. The third inner port 12f opens toward the flow recess 24e. Accordingly, the flow recess 24e communicates with the reservoir 19 via the third inner port 12f and the sixth port 11g.

  The spool piston 23 has a cylindrical shape having a circular cross section. The spool piston 23 is inserted into the spool cylinder 24 so as to be slidable in the front-rear direction. The rear end portion 23 a of the spool piston 23 is inserted into the holding recess 33 c of the holding piston 33, and the spool piston 23 is held by the holding piston 33.

  A buffer member 37 is provided between the bottom of the holding recess 33 c and the rear end surface of the spool piston 23. In the present embodiment, the buffer member 37 is made of a cylindrical rubber having elasticity, but may be a biasing member such as a coil spring or a diaphragm spring.

  A third spool recess 23b is formed in the middle of the longitudinal direction of the outer peripheral surface of the spool piston 23 over the entire circumference. A fourth spool recess 23c is formed in the outer peripheral surface of the spool piston 23 at the rear position of the third spool recess 23b over the entire circumference. A flow hole 23e is formed in the spool piston 23 from its front end to a position slightly rearward from the middle. The spool piston 23 is formed with a first flow port 23d and a second flow port 23f that communicate with the fourth spool recess 23c and the flow hole 23e.

  As shown in FIG. 2, in the space 11 p of the master cylinder 11 behind the receiving portion 14 c of the second master piston 14, the second master piston 14, the space 11 p of the master cylinder 11, the front end of the spool piston 23, the spool cylinder 24. The space surrounded by the front end of the servo chamber 10c.

  As shown in FIG. 2, the first spool spring receiver 38 includes a receiving portion 38 a and an attachment portion 38 b. The receiving portion 38a has a disk shape. The receiving portion 38a is attached to the front side of the distal end cylindrical portion 12a so as to close the opening of the distal end cylindrical portion 12a of the fail cylinder 12. The attachment portion 38b has a cylindrical shape and is formed to protrude forward from the center of the front surface of the receiving portion 38a. A screw groove is formed on the inner peripheral surface of the attachment portion 38b. At the center of the rear surface of the receiving portion 38a, a protruding portion 38c is formed to protrude rearward. The receiving portion 38a is formed with a circulation hole 38d communicating in the front-rear direction.

  The pressing member 40 has a rod shape. The rear portion of the pressing member 40 is screwed into the thread groove of the attachment portion 38b.

  As shown in FIG. 3, the second spool spring receiver 39 has a bottomed cylindrical main body 39a having a bottom 39c at the front end thereof, and a ring-shaped receiver extended outwardly at the rear end of the main body 39a. Part 39b. The front end of the spool piston 23 is fitted to the inner peripheral surface of the main body 39a, and the second spool spring receiver 39 is attached to the tip of the spool piston 23. A communication hole 39d is formed in the bottom 39c. As shown in FIG. 2, the second spool spring receiver 39 faces the protruding portion 38c of the first spool spring receiver 38 with a predetermined distance therebetween.

  As shown in FIGS. 2 and 3, the spool spring 25 is provided between the receiving portion 38 a of the first spool spring receiver 38 and the receiving portion 39 b of the second spool spring receiver 39. The spool piston 25 is urged backward by the spool spring 25 with respect to the fail cylinder 12 (master cylinder 11) and the spool cylinder 24.

  The spring constant of the simulator spring 26 is set larger than the spring constant of the spool spring 25. Further, the spring constant of the simulator spring 26 is set larger than the spring constant of the pedal return spring 27.

(Simulator)
Hereinafter, a “simulator” including the simulator spring 26, the pedal return spring 27, and the simulator rubber 34 will be described. The “simulator” is a mechanism that generates a load (reaction force) on the brake pedal 71 in accordance with the stroke of the brake pedal 71 and reproduces an operational feeling (feeling force) of a normal brake device.

  When the brake pedal 71 is depressed, first, the pedal return spring 27 is contracted. At this time, the reaction force acting on the brake pedal 71 is obtained by adding a value obtained by multiplying the set load of the pedal return spring 27 by the spring constant of the pedal return spring 27 to the stroke of the brake pedal 71 (the connecting member 31). Become.

  When the brake pedal 71 is further depressed and the simulator rubber 34 comes into contact with the holding piston 33, the pedal return spring 27 and the simulator spring 26 are contracted. At this time, the reaction force acting on the brake pedal 71 is a composite value of the load generated by the simulator spring 26 and the pedal return spring 27. For this reason, the amount of increase in the reaction force acting on the brake pedal 71 per stroke of the brake pedal 71 becomes larger than before the simulator rubber 34 contacts the holding piston 33.

  Since the simulator rubber 34 exists, the simulator rubber 34 is actually compressed when the brake pedal 71 is further depressed after the simulator rubber 34 abuts the holding piston 33. Due to the nature of the simulator rubber 34, the spring constant gradually increases as it is compressed. For this reason, the reaction force acting on the brake pedal 71 per stroke of the brake pedal 71 gradually changes before and after the simulator rubber 34 contacts the holding piston 33, and the driver's uncomfortable feeling due to the sudden change of the reaction force is suppressed. The

  Thus, until the simulator rubber 34 comes into contact with the holding piston 33, the amount of increase in the reaction force acting on the brake pedal 71 per stroke of the brake pedal 71 is small, and after the simulator rubber 34 comes into contact with the holding piston 33, The amount of increase in the reaction force acting on the brake pedal 71 per stroke of the brake pedal 71 is increased, so that the operational feeling of a normal brake device is reproduced.

(Pressure regulator)
The pressure adjusting device 53 increases or decreases the wheel cylinder pressure generated in the wheel cylinders WCfl, WCfr, WCrl, WCrr, and realizes well-known antilock brake control and side slip prevention control. Wheel cylinders WCfr and WCfl are connected to the first port 11b communicating with the first master chamber 10a via the main flow path 52 and the pressure regulator 53. The wheel cylinders WCrr and WCrl are connected to the third port 11d communicating with the second master chamber 10b via the main flow path 51 and the pressure regulator 53.

  Here, the configuration of supplying the wheel cylinder pressure to one of the four wheel cylinders (WCfr) will be described for the pressure adjusting device 53, and the description of the other configurations is omitted because they are the same. As shown in FIG. 2, the pressure adjusting device 53 includes a holding valve 531, a pressure reducing valve 532, a pressure adjusting reservoir 533, a pump 534, a motor 535, a differential pressure control valve 536, and a master pressure sensor 539. The holding valve 531 is a normally-open electromagnetic valve, and opening / closing thereof is controlled by the brake ECU 6. One of the holding valves 531 is connected to the differential pressure control valve 536, and the other is connected to the wheel cylinder WCfr and the pressure reducing valve 532.

  The pressure reducing valve 532 is a normally closed electromagnetic valve, and opening / closing thereof is controlled by the brake ECU 6. One of the pressure reducing valves 532 is connected to the wheel cylinder WCfr and the holding valve 531, and the other is connected to the storage chamber 533 e of the pressure regulating reservoir 533 through the pressure reducing flow path 157. When the pressure reducing valve 532 is opened, the wheel cylinder WCfr communicates with the storage chamber 533e of the pressure regulating reservoir 533, and the wheel cylinder pressure of the wheel cylinder WCfr decreases.

  The differential pressure control valve 536 is a normally open electromagnetic valve, and is controlled by the brake ECU 6. One of the differential pressure control valves 536 is connected to the first port 11 b communicating with the first master chamber 10 a, and the other is connected to the holding valve 531. That is, the differential pressure control valve 536 is provided in the main flow path 52 between the first master chamber 10a and the wheel cylinder WCfr. When the differential pressure control valve 536 is energized, the differential pressure control valve 536 enters the differential pressure state, and the first master from the wheel cylinder WCfr side only when the wheel cylinder pressure becomes higher than the master pressure Pm by the control differential pressure. Distribution of brake fluid to the chamber 10a side is allowed.

  When the differential pressure control valve 536 is in a differential pressure state, the wheel cylinder pressure is maintained higher than the master pressure Pm by a control differential pressure by brake fluid pressurized by a pump 534 described later. That is, when the master pressure Pm is 0, the wheel cylinder pressure is a control differential pressure. The control differential pressure increases in proportion to the amount of current supplied to the differential pressure control valve 536. The amount of current supplied to the differential pressure control valve 536 is linear current controlled by the brake ECU 6. Here, the linear current control includes PWM control that changes the voltage DUTY ratio for driving the differential pressure control valve 536 and changes the effective current.

  The pressure regulation reservoir 533 includes a cylinder 533a, a piston 533b, a spring 533c, and a flow path adjustment valve 533d. A piston 533b is slidably provided in the cylinder 533a. A storage chamber 533e is formed by a space surrounded by the cylinder 533a and the piston 533b. As the piston 533b slides, the volume of the storage chamber 533e changes. Brake fluid is stored in the storage chamber 533e. The spring 533c is provided in a space between the bottom of the cylinder 533a and the piston 533b, and urges the piston 533b in a direction to reduce the volume of the storage chamber 533e.

  The first master chamber 10a side of the main flow path 52 with respect to the differential pressure control valve 536 is connected to the storage chamber 533e via the first suction flow path 158 and the flow path adjustment valve 533d. As the pressure in the storage chamber 533e increases, that is, as the piston 533b slides in a direction in which the volume of the storage chamber 533e increases, the flow path between the storage chamber 533e and the first suction flow path 158 by the flow path adjustment valve 533d. Is squeezed.

  The pump 534 is driven by the operation of the motor 535 according to the command from the brake ECU 6. The suction port of the pump 534 is connected to the storage chamber 533 e via the second suction channel 159. The discharge port of the pump 534 is connected to the main flow path 52 between the differential pressure control valve 536 and the holding valve 531 via the pump pressurization flow path 156. A check valve z is provided in the pump pressurization flow path 156. The check valve z here allows the flow from the pump 534 to the main flow path 52 (first master chamber 10a) and restricts the flow in the reverse direction. Note that a damper (not shown) may be provided on the upstream side of the pump 534 in order to reduce the pulsation of the brake fluid discharged by the pump 534.

  The first suction flow path 158 is provided with a master pressure sensor 539 that detects the master pressure Pm by detecting the hydraulic pressure in the first suction flow path 158 and outputs the detected value to the brake ECU 6. .

  In the state where the master pressure Pm is not generated in the first master chamber 10a, the pressure in the storage chamber 533e connected to the first master chamber 10a via the first suction channel 158 is not high. The flow path between the first suction flow path 158 and the storage chamber 533e is not restricted by the valve 533d. For this reason, the pump 534 can suck the brake fluid from the first master chamber 10a through the first suction flow path 158 and the storage chamber 533e.

  On the other hand, when the master pressure Pm rises in the first master chamber 10a, the flow regulating valve 533d is operated by the force that the master pressure Pm acts on the piston 533b via the first suction flow channel 158, and the flow channel is adjusted. The flow path between the storage chamber 533e and the first suction flow path 158 is throttled and closed by the adjustment valve 533d.

  When the pump 534 is driven in this state, the brake fluid in the storage chamber 533e is discharged by the pump 534. When a brake fluid of a predetermined amount or more is supplied from the storage chamber 533e to the pump 534, the flow path between the storage chamber 533e closed by the flow path adjustment valve 533d and the first suction flow path 158 is slightly opened. The brake fluid is supplied from the first master chamber 10 a to the storage chamber 533 e via the first suction flow path 158 and then supplied to the pump 534.

  When the pressure regulator 53 is in the pressure reducing mode, the pressure reducing valve 532 is opened, and the wheel cylinder pressure of the wheel cylinder WCfr decreases. Then, the differential pressure control valve 536 is opened, and the pump 534 sucks in the brake fluid in the wheel cylinder WCfr or the brake fluid stored in the storage chamber 533e and returns it to the first master chamber 10a.

  In the pressure increasing mode of the pressure regulator 53, the pressure reducing valve 532 is closed, the holding valve 531 is opened, the differential pressure control valve 536 is in a differential pressure state, and the brake fluid pressurized by the pump 534 is applied to the wheel cylinder. By being supplied to WCfr, a wheel cylinder pressure higher than the master pressure Pm by the control differential pressure is generated in the wheel cylinder WCfr. In the following description, the pressurization amount of the wheel cylinder pressure by the pump 534 and the differential pressure control valve 536, that is, the pressurization amount of the wheel cylinder pressure with respect to the master pressure Pm is represented as the pressurization amount Pp. That is, the pressurization amount Pp is equal to the control differential pressure.

  In the holding mode of the pressure regulator 53, the pressure reducing valve 532 is closed and the holding valve 531 is closed, and the wheel cylinder pressure of the wheel cylinder WCfr is held.

  As described above, the pressure adjusting device 53 adjusts the wheel cylinder pressure regardless of the operation of the brake pedal 71.

(Operation of hydro booster)
Below, operation | movement of the hydro booster 10 is demonstrated. In response to an operating force (pedal load) input to the brake pedal 71, a “pressure adjusting unit” composed of the spool cylinder 24 and the spool piston 23 is driven, and the hydro booster 10 is operated in the “decompression mode”, “pressure increase mode”, It can be switched to one of the “holding modes”.

[Decompression mode]
When the brake pedal 71 is not depressed or when the brake stroke Bs is equal to or less than the master pressure generation stroke Sm (shown in FIG. 4), the “decompression mode” is set. As shown in FIG. 2, in a state where the brake pedal 71 is not depressed, that is, in the “decompression mode”, the simulator rubber 34 (moving member 32) and the bottom 33 a of the holding piston 33 are separated from each other.

  In a state where the simulator rubber 34 and the bottom 33a of the holding piston 33 are separated from each other, the spool piston 23 is moved toward the “reduced pressure position” (shown in FIG. 3) by the urging force of the spool spring 25. ). In this state, as shown in FIG. 3, the spool port 24 c is closed by the outer peripheral surface of the spool piston 23. That is, the accumulator pressure from the accumulator 61 does not act on the servo chamber 10c.

  Further, as shown in FIG. 3, the fourth spool recess 23 c of the spool piston 23 communicates with the second spool recess 24 f of the spool cylinder 24. That is, the servo chamber 10c includes a flow hole 23e, a first flow port 23d, a fourth spool recess 23c, a second spool recess 24f, a flow path 12n, a flow recess 24e, a third inner port 12f, and a sixth port 11g. It communicates with the reservoir 19 via a “decompression channel”. For this reason, in the “decompression mode”, the servo chamber 10c is the same as the atmospheric pressure, and the master pressure Pm is not generated in the first master chamber 10a and the second master chamber 10b.

  Even if the brake pedal 71 is stepped on and the simulator rubber 34 comes into contact with the bottom 33a of the holding piston 33 and a forward input load is applied to the spool piston 23 via the holding piston 33, the input load is applied to the spool spring. When the urging force is smaller than 25, the spool piston 23 is positioned at the “decompression position” without moving forward. The input load is a force obtained by subtracting a load necessary for the pedal return spring 27 to be compressed by the operation force from the load input to the connecting member 31 by the operation of the brake pedal 71. In a state where the brake stroke Bs is equal to or less than the master pressure generation stroke Sm, the hydro booster 10 is not in the “pressure increasing mode”, the servo pressure and the master pressure are not generated, and the friction braking devices Bfl, Bfr, Brl, Brr “Friction braking force” is not generated.

[Pressure increase mode]
When the brake stroke Bs becomes larger than the master pressure generation stroke Sm, the hydro booster 10 enters the “pressure increasing mode”. That is, when the holding piston 33 is pressed by the simulator rubber 34 (moving member 32) by the operating force input to the brake pedal 71 and a forward load is applied to the spool piston 23, the spool piston 23 is attached to the spool spring 25. It moves to the “pressure increasing position” ahead of the sliding range of the spool piston 23 against the force (the state of FIG. 5).

  As shown in FIG. 5, in the state where the spool piston 23 is located at the “pressure increasing position”, the first flow port 23d is closed by the inner peripheral surface of the spool cylinder 24, and the first flow port 23d and the second spool The recess 24f is blocked. For this reason, the servo chamber 10c and the reservoir 19 are shut off.

  Further, when the spool piston 23 is positioned at the “pressure increasing position”, the spool port 24 c communicates with the third spool recess 23 b. Further, the third spool recess 23b, the first spool recess 24d, and the fourth spool recess 23c communicate with each other. For this reason, the accumulator pressure from the accumulator 61 causes the first inner port 12d, the spool port 24c, the third spool recess 23b, the first spool recess 24d, the fourth spool recess 23c, the second flow port 23f, the flow hole 23e, and the communication. The servo pressure is increased by being supplied to the servo chamber 10c through the “pressure-increasing flow path” formed by the holes 39d.

  When the servo pressure increases, the second master piston 14 moves forward due to the servo pressure, and the first master piston 13 pressed by the second return spring 18 also moves forward. Then, the master pressure Pm is generated in the second master chamber 10b and the first master chamber 10a. As the servo pressure increases, the master pressure Pm increases. In the present embodiment, the seal diameters on the front and rear sides of the second master piston 14 and the seal diameters on the front and rear sides of the first master piston 13 are the same. Therefore, the servo pressure and the master pressure Pm generated in the second master chamber 10b and the first master chamber 10a are the same.

  When the master pressure Pm is generated in the second master chamber 10b and the first master chamber 10a, the wheel cylinders WCfr, WCfl, Brake fluid is supplied to WCrr, WCrl, and wheel cylinder pressure is generated in the wheel cylinders WCfr, WCfl, WCrr, WCrl, and friction braking force is generated. The wheel cylinder pressure is the total pressure of the master pressure Pm and the pressurization amount Pp.

[Retention mode]
In a state where the spool piston 23 is in the “pressure increasing position”, the accumulator pressure acts on the servo chamber 10c, and the servo pressure increases. Then, a restoring force obtained by multiplying the servo pressure by the cross-sectional area (seal area) of the spool piston 23 acts on the spool piston 23 backward. When the resultant force of the return force and the urging force of the spool spring 25 becomes larger than the input load acting on the spool piston 23, the spool piston 23 moves rearward and is at a position between the “decompression position” and the “pressure increase position”. It is positioned at a certain “holding position” (state shown in FIG. 6).

  As shown in FIG. 6, the spool port 24 c is closed by the outer peripheral surface of the spool piston 23 when the spool piston 23 is in the “holding position”. Therefore, the spool port 24c and the second flow port 23f are blocked, the servo chamber 10c and the accumulator 61 are blocked, and the accumulator pressure does not act on the servo chamber 10c.

  Further, the first flow port 23 d is closed by the inner peripheral surface of the spool cylinder 24. For this reason, the first flow port 23d and the second spool recess 24f are blocked, and the servo chamber 10c and the reservoir 19 are blocked. Therefore, the servo chamber 10c is hermetically sealed, and the servo pressure at the time of switching from the “pressure increasing mode” to the “holding mode” is maintained.

  When the resultant force of the restoring force acting on the spool piston 23 and the urging force of the spool spring 25 balances the input load acting on the spool piston 23, the “holding mode” is maintained. On the other hand, the operation force to the brake pedal 71 is reduced, the input load acting on the spool piston 23 is reduced, and the resultant force of the return force acting on the spool piston 23 and the biasing force of the spool spring 25 is applied to the spool piston 23. When the input load becomes larger than the applied input load, the spool piston 23 moves rearward and is positioned at the “decompression position” (shown in FIG. 3) to enter the “decompression mode”, and the servo pressure in the servo chamber 10c decreases.

  On the other hand, when the spool piston 23 is in the “holding position”, the operating force input to the brake pedal 71 is increased, and the operating force acting on the spool piston 23 is increased to act on the spool piston 23. When the input load to be applied becomes larger than the resultant force of the return force acting on the spool piston 23 and the urging force of the spool spring 25, the spool piston 23 moves forward and is positioned at the “pressure increasing position” (shown in FIG. 5). “Pressurization mode” is entered, and the servo pressure in the servo chamber 10c increases.

  In addition, hysteresis occurs in the movement of the spool piston 23 due to resistance such as sliding resistance between the outer peripheral surface of the spool piston 23 and the inner peripheral surface of the spool cylinder 24, and the movement of the spool piston 23 in the front-rear direction is caused by the hysteresis. Be inhibited. Therefore, the “holding mode” is not frequently switched to the “depressurization mode” or the “holding mode” to the “pressure increasing mode”.

(Relationship between regenerative braking force and friction braking force)
Hereinafter, the relationship between the regenerative braking force and the friction braking force will be described with reference to FIG. As shown in FIG. 4, when the brake stroke Bs is equal to or less than the master pressure generation stroke Sm, the hydro booster 10 does not switch from the “pressure reduction mode” to the “pressure increase mode” but remains in the “pressure reduction mode” and depends on the master pressure Pm. No friction braking force is generated.

  As shown in FIG. 4, when the brake stroke Bs is equal to or less than the master pressure generation stroke Sm, the brake ECU 6 determines that the total value of the regenerative braking force and the friction braking force generated by the pump pressurization generated by the pump 534 is “control control. The pressure regulating device 53 is controlled so as to be “power”. The “control braking force” is calculated by the brake ECU 6 based on the brake stroke Bs detected by the brake sensor 72. That is, as the brake stroke Bs increases, a larger value of “control braking force” is calculated.

  When the brake stroke Bs is larger than the master pressure generation stroke Sm, the hydro booster 10 is switched from the “pressure reduction mode” to the “pressure increase mode”, and a friction braking force is generated by the master pressure Pm. Then, the brake ECU 6 calculates “control braking force” when the brake stroke Bs is the master pressure generation stroke Sm as “control braking force”. That is, even if the brake stroke Bs becomes larger than the master pressure generation stroke Sm, the “control braking force” when the brake stroke Bs is the master pressure generation stroke Sm is maintained, and the “control braking force” does not increase. Then, the brake ECU 6 controls the pressure adjusting device 53 so that the total value of the regenerative braking force and the friction braking force by the pump pressurization that is the hydraulic pressure generated by the pump 534 of the pressure adjusting device 53 becomes the “control braking force”. To control. As a result, the total braking force applied to the vehicle is the sum of the “control braking force” and the friction braking force generated by the master pressure Pm.

(Replacement from regenerative braking to friction braking by pump pressurization)
When the vehicle speed V of the vehicle falls below a predetermined speed, the regenerative braking device A cannot generate a regenerative braking force. When the vehicle speed V becomes equal to or lower than the first specified speed V1 (for example, 10 km / h), the hybrid ECU 9 gradually decreases the regenerative braking force in accordance with the decrease in the vehicle speed V as shown in 1 of FIG. Then, the switching from the regenerative braking to the friction braking by pump pressurization (hereinafter, abbreviated as “replacement” as appropriate) is executed to increase the friction braking force by pump pressurization by the decrease of the regenerative braking force. This replacement is completed when the vehicle speed V reaches the second specified speed V2 (for example, 5 km), and when the vehicle speed V reaches the second specified speed V2, the regenerative braking force is zero.

  When the friction braking force due to pump pressurization is increased by the differential pressure control valve 536, the brake fluid flows from the master chambers 10a, 10b to the wheel cylinders WCfl, WCfr, WCrl, WCrr, the master pressure Pm decreases, and the master pressure The friction braking force due to Pm decreases (2 in FIG. 8), and the total braking force decreases (3 in FIG. 8). When the spool piston 23 slides forward after the master pressure Pm decreases and the hydro booster 10 enters the “pressure increasing mode”, the master pressure Pm recovers to a value corresponding to the brake stroke Bs. The friction braking force due to the pressure Pm is restored (4 in FIG. 8).

  In the present embodiment, as shown in 1 of FIG. 9, at the time of replacement, the decrease in the regenerative braking force is added to the friction braking force due to the pump pressurization, thereby reducing the total braking force due to the decrease in the master pressure Pm. Is preventing. In FIG. 9, the broken line represents the friction braking force due to the pump pressurization when the “pressurization amount correction process” described below is not executed. Hereinafter, description will be made with reference to the time chart shown in FIG. 9 and the flowcharts shown in FIGS.

(Brake control process)
When the vehicle is ready to run, the “braking control process” shown in FIG. 10 starts, and the program proceeds to S10. In S10, when the brake ECU 6 determines that the brake pedal 71 is operated based on the detection signal from the brake sensor 72 (S10: YES), the program proceeds to S11, and the brake pedal 71 is not operated. (S10: NO), the process of S10 is repeated.

  In S <b> 11, the brake ECU 6 calculates a “control braking force” based on the brake stroke Bs detected by the brake sensor 72. When S11 ends, the program proceeds to S12.

  In S <b> 12, the brake ECU 6 transmits “control braking force” to the hybrid ECU 9. When S12 ends, the program proceeds to S13.

  The hybrid ECU 9 calculates an “executed regenerative braking force” that is a regenerative braking force that can be actually generated in the regenerative braking device A, based on the vehicle speed V, the state of charge of the battery 507, and the “control braking force”. To do. Further, the “execution regenerative braking force” is calculated so as not to exceed the “control braking force”. Then, the hybrid ECU 9 transmits “execution regenerative braking force” to the brake ECU 6.

  In S13, the brake ECU 6 receives “execution regenerative braking force”. When S13 ends, the program proceeds to S14.

  In S14, the brake ECU 6 calculates the friction braking force by pump pressurization by subtracting the “execution regenerative braking force” from the “control braking force”. Next, the brake ECU 6 calculates the pressurization amount Pp at which the friction braking force generated by the pump pressurization calculated above is generated in the friction braking devices Bfl, Bfr, Brl, Brr. When S14 ends, the program proceeds to S15.

  In S15, the brake ECU 6 executes a “pressurization amount correction process”. The “pressurization amount correction process” will be described with reference to the flowchart shown in FIG. When the “pressurization amount correction process” is started, if the brake ECU 6 determines in S109 that the replacement has started (S109: YES), the program proceeds to S110 and it is determined that the replacement has not started. If so (S109: NO), the program proceeds to S111. The brake ECU 6 determines that the replacement has started when it is determined that the vehicle speed V has become equal to or lower than the first specified speed V1 for the first time, or when it is determined that a signal for starting replacement has been received from the hybrid ECU 9.

  In S110, the brake ECU 6 stores the effective regenerative braking force BFrs at the time of starting replacement in the “storage unit”. When S110 ends, the program proceeds to S111.

  If the brake ECU 6 determines in S111 that replacement is in progress (S111: YES), the program proceeds to S131. If it is determined that replacement is not in progress (S111: NO), the program proceeds to S121. When the brake ECU 6 determines that the vehicle speed V is between the first specified speed V1 and the second specified speed V2, or receives a signal during replacement from the hybrid ECU 9, the brake ECU 6 determines that replacement is being performed. To do.

  In S121, the brake ECU 6 sets 0 as the correction amount C and advances the program to S122.

  In S122, the brake ECU 6 sets the master pressure increase flag to OFF and advances the program to S181.

  In S131, when the brake ECU 6 determines that the master pressure Pm is increased and the master pressure increase flag is OFF based on the detection signal from the master pressure sensor 539 (S131: YES), the program is executed in S161. If it is determined that the master pressure Pm is decreased or the master pressure increase flag is ON (S131: NO), the program proceeds to S141. In addition, as shown in 2 of FIG. 9, when the decreasing master pressure Pm increases first, it is judged as YES in S131.

  In S141, when the brake ECU 6 determines that the master pressure increase flag is OFF (S141: YES), the program proceeds to S151, and when it is determined that the master pressure increase flag is ON (S141: NO), the program proceeds to S171.

In S151, the brake ECU 6 calculates the effective regenerative braking force reduction amount ΔBFr based on the following equation (1).
ΔBFr = BFrs−BFr (1)
ΔBFr: Execution regenerative braking force decrease amount BFrs: Execution regenerative braking force at the start of replacement BFr: Current execution regenerative braking force When S151 ends, the program proceeds to S152.

  In S152, the brake ECU 6 calculates the correction amount C from the effective regenerative braking force decrease amount ΔBFr. The correction amount C is a pressurization amount (hydraulic pressure) by pump pressurization that generates the same frictional braking force as the absolute value of the effective regenerative braking force decrease amount ΔBFr. When S152 ends, the program proceeds to S181.

  In S161, the brake ECU 6 has a master pressure increase correction amount C1 that is a correction amount C when the master pressure Pm is increased (when YES is determined in S131), and an execution regenerative braking force BFrm when the master pressure Pm is increased. The execution regenerative braking force BFrm1 when the master pressure is increased is stored. When S161 ends, the program proceeds to S162.

  In S162, the brake ECU 6 sets the master pressure increase flag to ON and advances the program to S141.

In S171, the brake ECU 6 calculates and sets the correction amount C based on the following equation (2).
C = C1 × BFr / BFrm1 (2)
C: Correction amount C1: Correction amount when master pressure is increased BFr: Current execution regenerative braking force BFrm1: Execution regenerative braking force when master pressure is increased Note that the calculated correction amount C is the correction amount C calculated in the previous S171. If it is greater, the brake ECU 6 sets the correction amount C calculated in the previous S171. The brake ECU 6 sets the correction amount C so as not to be less than 0.
When S171 ends, the program proceeds to S181.

In S181, the brake ECU 6 calculates the corrected pressurization amount Ppc based on the following equation (3).
Ppc = Pp + C (3)
Ppc: Corrected pressurization amount Pp: Pressurization amount C: Correction amount When S181 ends, the “pressurization amount correction process” ends, and the program proceeds to S16 in FIG.

  In S16, the brake ECU 6 controls the differential pressure control valve 536 so that the control differential pressure generated by the differential pressure control valve 536 becomes the corrected pressurization amount Ppc by setting the pressure regulating device 53 to the “pressure increasing mode”. The motor 535 is driven. When S16 ends, the program returns to S10.

(Effect of this embodiment)
As is clear from the above description, the brake ECU 6 (pressurization amount calculation unit) calculates the “control braking force” based on the brake stroke Bs detected by the brake sensor 72 in S11 of FIG. In S14, the brake ECU 6 calculates the friction braking force by pump pressurization by subtracting the “executed regenerative braking force” from the “control braking force”, and then calculates the pressurization amount Pp. Thus, since the pressurization amount Pp is calculated regardless of the master pressure Pm, the pressurization amount Pp does not change due to the change in the master pressure Pm. As a result, the control differential pressure by the differential pressure control valve 536 does not change, and the brake fluid does not flow between the differential pressure control valve 536 and the master chambers 10a, 10b, so the master pressure Pm also does not change. For this reason, the occurrence of a hunting phenomenon in which the master pressure Pm repeatedly increases and decreases due to a sudden change in the master pressure Pm is prevented.

  As shown in 1 of FIG. 9, the brake ECU 6 (pressurization amount correction unit) applies an increase based on the decrease amount of the effective regenerative braking force BF when the replacement of the regenerative braking force with the friction braking force is executed. Correction for increasing the pressure amount Pp is performed. Thereby, even if the pressurization amount Pp is increased by switching from the regenerative braking force to the friction braking force by pump pressurization and the master pressure Pm is decreased, the pressurization amount Pp is based on the decrease amount of the regenerative braking force. Increased correction is performed. Therefore, it is possible to provide a friction braking unit B (vehicle braking device) that can prevent a decrease in the friction braking force and generate an appropriate friction braking force.

  In S151 and S152 of FIG. 11, the brake ECU 6 (pressurization amount correction unit) reduces the amount of execution regenerative braking force BFr from the execution regenerative braking force BFrs stored in the “storage unit” at the start of replacement (execution regenerative braking). Correction is performed by adding the hydraulic pressure at which the same friction braking force as the absolute value of the braking force reduction amount ΔBFr) is added to the pressurization amount Pp as the correction amount C. As a result, the amount of decrease in the master pressure Pm corresponding to the effective regenerative braking force decrease amount ΔBFr (3 in FIG. 9) is added as the correction amount C to the pressurization amount Pp. Can be prevented.

  When the brake ECU 6 (pressurization amount correction unit) detects an increase in the master pressure Pm during execution of replacement (determined as YES in 2 in FIG. 9 and S131 in FIG. 11), as shown in 4 in FIG. Then, the reduction of the correction amount C is started. As a result, when the spool piston 23 slides forward and the hydro booster 10 enters the “pressure increasing mode” and the master pressure Pm increases, the correction amount C decreases, so that excessive friction braking force is generated. Is prevented.

  In S171 of FIG. 11, the brake ECU 6 (pressurization amount correction unit) decreases the correction amount C according to the decrease amount of the effective regenerative braking force BFr based on the above equation (2). As a result, when the master pressure Pm increases during replacement, the correction amount C gradually decreases according to the decrease amount of the effective regenerative braking force BFr, so that the total braking force is generated without excess or deficiency. Further, since the correction amount C gradually decreases, a sudden change in the total braking force is prevented, and a sudden change in the vehicle deceleration is prevented. Further, since the correction amount C is 0 at the end of replacement (T3 in FIG. 9), excessive friction braking force is prevented from being generated at the end of replacement.

  In the friction braking unit B of this embodiment, the spool piston 23 slides in the front-rear direction by the driver's operating force input to the brake pedal 71, thereby generating a master pressure Pm corresponding to the driver's operating force. To do. On the other hand, in the friction braking unit in which the brake pedal is mechanically connected to the master piston and the operating force of the driver input to the brake pedal directly acts on the master piston to generate master pressure, the following problems occur. Arise. That is, in a situation where the pressurization amount Pp is increasing, the brake fluid from the master chamber is sucked out by the pump, the master piston slides forward, the brake pedal moves forward, and the brake pedal The driver who operates the vehicle feels uncomfortable. However, in the friction braking unit B of the present embodiment, even if the brake fluid is sucked out from the master chambers 10a and 10b by the pump 535 and the master pistons 13 and 14 slide forward as the pressurization amount Pp increases. Since the brake pedal 71 is not mechanically connected to the master pistons 13 and 14, the brake pedal 71 does not move forward, and the driver operating the brake pedal 71 does not feel uncomfortable.

  The moving member 32 is separated from the holding piston 33 holding the spool piston 23. For this reason, even if the brake pedal 71 is stepped on, the operation force from the brake pedal 71 is not transmitted to the spool piston 23 until the simulator rubber 34 attached to the moving member 32 comes into contact with the holding piston 33, and the brake piston 71 Since the master pressure Pm is generated until the stroke Bs reaches the master pressure generation stroke Sm (shown in FIG. 4), the friction braking force by the master pressure Pm is not generated. As described above, as shown in FIG. 4, since the friction braking force by the master pressure Pm is not generated until the brake stroke Bs reaches the master pressure generation stroke Sm, the motion of the vehicle in the friction braking devices Bfl, Bfr, Brl, Brr. The energy is prevented from being dissipated as heat energy, and more kinetic energy of the vehicle can be recovered as electric power in the regenerative braking device A.

  Further, the “pressure reduction mode”, “pressure increase mode”, and “holding mode” are switched depending on the position of the spool piston 23 driven by the operation force from the brake pedal 71 in the front-rear direction, and the “friction braking force” is switched. Is variable. As described above, since the “friction braking force” is made variable by the “spool valve” which is a mechanical component composed of the spool piston 23 and the spool cylinder 24, the “friction braking force” is set using the electromagnetic valve. Compared to a variable structure, the “friction braking force” can be made linearly variable.

  In other words, in the solenoid valve, when the valve body is opened away from the valve seat, a force that separates the valve body from the valve seat is generated by the flow of the brake fluid, the brake fluid flows out excessively, and it is difficult to adjust the pressure. As a result, it is difficult to control the increase and decrease of the “friction braking force” linearly. On the other hand, in the present embodiment, the driver's operating force acts on the spool piston 23, and the increase / decrease of the operating force switches between the “decompression mode”, the “pressure increase mode”, and the “holding mode”. Since “power” increases or decreases, “friction braking force” in accordance with the driver's intention can be generated.

(Another embodiment)
In the embodiment described above, the brake sensor 72 that detects the operation amount input to the brake pedal 71 detects the stroke of the brake pedal 71. However, the brake sensor 72 may be a stroke sensor that detects the stroke of the input member such as the input piston 15, the connecting member 31, and the operating rod 16. Alternatively, the brake sensor 72 may be a load sensor that detects an operation force of the driver acting on the brake pedal 71, the input piston 15, the connecting member 31, and the operating rod 16.

  The master pressure sensor 539 for detecting the master pressure may be provided in the main flow path 52.

  In the embodiment described above, the input member to which the driver's operating force is input is the brake pedal 71. However, the input member is not limited to the brake pedal 71, and may be a brake lever or a brake handle, for example.

  At the time of replacement, the brake ECU 6 does not correct the pressurization amount Pp, but adds a hydraulic pressure equivalent to twice the effective regenerative braking force reduction amount ΔBFr to the pressurization amount Pp at the start of replacement. The embodiment for calculating the pressurization amount Pp may be used. Then, the pressurization amount Pp calculated by such an embodiment is corrected by adding the hydraulic pressure corresponding to the effective regenerative braking force decrease amount ΔBFr as the correction amount C to the pressurization amount Pp. It is the same value as the pressure amount Ppc. Therefore, it should be understood that such embodiments are also included in the technical scope of the present invention.

  6 ... Brake ECU (pressurization amount calculation unit, hydraulic pressure control unit, pressurization amount correction unit, storage unit), 10a ... first master chamber, 10b ... second master chamber, 11 ... master cylinder, 13 ... first master Piston, 14 ... second master piston, 19 ... reservoir, 23 ... spool piston (spool valve), 24 ... spool cylinder (spool valve), 32 ... moving member, 61 ... accumulator, 71 ... brake pedal (input member), 72 ... Brake sensor (operation amount detection unit), 536 ... Differential pressure control valve, 539 ... Master pressure sensor (master pressure detection unit), A ... Regenerative braking device, B ... Friction braking unit (vehicle braking device), Bfl, Bfr , Brl, Brr ... friction braking device, Sfl, Sfr, Srl, Srr ... wheel speed sensor, WCfl, WCfr, WCrl (vehicle speed detector), WCrr ... wheel system Sunda

Claims (6)

An input member (71) to which the operating force of the driver is input;
An operation amount detector (72) for detecting an operation amount of the input member;
A friction braking device (Bfl, Bfr, Brl, Brr) that generates a friction braking force by the wheel cylinder pressure input to the wheel cylinder (WCfl, WCfr, WCrl, WCrr);
A master chamber (10a, 10b) connected to the wheel cylinder is formed, and a master cylinder (11) for generating in the master chamber a master pressure corresponding to the operating force of the driver input to the input member;
A differential pressure control valve (536) which is provided in a flow path between the master chamber and the wheel cylinder and maintains the wheel cylinder pressure higher than the master pressure by a control differential pressure corresponding to a current when energized; ,
A regenerative braking device (A) for generating a regenerative braking force;
A pressurization amount calculation unit (6) for calculating a pressurization amount based on the operation amount detected by the operation amount detection unit and the regenerative braking force generated by the regenerative braking device;
A hydraulic pressure control section (6) for controlling the current supplied to the differential pressure control valve to pressurize the wheel cylinder pressure by the pressurization amount with respect to the master pressure;
A vehicle having a pressurization amount correction unit (6) for performing correction to increase the pressurization amount based on the decrease amount of the regenerative braking force when the regenerative braking force is replaced with the friction braking force. Braking device. A storage unit for storing the regenerative braking force at the time of starting the replacement;
The pressurization amount correction unit uses the hydraulic pressure at which the same friction braking force as the absolute value of the reduction amount of the regenerative braking force from the regenerative braking force stored at the storage unit as the correction amount is stored as the correction amount. The vehicle braking device according to claim 1, wherein correction for adding to the amount of pressurization is performed. A master pressure detector (539) for detecting the master pressure;
The said pressurization amount correction | amendment part starts the reduction | decrease of the said correction amount, when the said master pressure detection part detects the increase in the said master pressure in execution of the said replacement. Vehicle braking system.   The vehicular braking apparatus according to claim 3, wherein the pressurization amount correction unit decreases the correction amount according to a decrease amount of the regenerative braking force. A columnar space (11p) is formed in the master cylinder in the front-rear direction,
An accumulator (61) for accumulating the fluid pressure of the brake fluid;
A reservoir (19) for storing brake fluid;
A master provided in the space of the master cylinder so as to be slidable in the front-rear direction, wherein the master chamber is formed with the master cylinder in the front, and a servo chamber (10c) is formed with the master cylinder in the rear Pistons (13, 14);
A decompression mode in which the servo chamber and the reservoir communicate with each other by sliding in the front-rear direction by the operating force of the driver input to the input member, provided behind the master piston in the space of the master cylinder; 5. The spool valve according to claim 1, further comprising: a pressure increasing mode in which the servo chamber and the accumulator communicate with each other, and a spool valve (23, 24) that switches a holding mode in which the servo chamber is sealed. Brake device for vehicles.   A moving member (32) which is provided behind the spool valve so as to be separated from the spool valve and is slidable in the front-rear direction in the space of the master cylinder and to which the operating force of the driver is input via the input member. The vehicle braking device according to claim 5, further comprising: