JP2010047044A - Vehicular brake device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To compensate for an increase in pad clearance of a wheel cylinder due to a knockback phenomenon in a brake device including a slave cylinder.
Even if a knock-back phenomenon occurs in a side force acting on a wheel during turning when the vehicle is not braked, and a piston of the wheel cylinders 16, 17; After a steering angle greater than a predetermined value or a lateral acceleration greater than a predetermined value is detected, that is, after a side force that causes a knockback phenomenon is generated, the slave cylinder 23 is operated for a predetermined time to generate a brake hydraulic pressure. Therefore, with the brake fluid pressure, the retracted piston of the wheel cylinders 16, 17; 20, 21 can be advanced to the normal position (position before the occurrence of knockback) to maintain the pad clearance at an appropriate value. It is possible to prevent a decrease in response of braking force generation accompanying an increase in pad clearance.
[Selection] Figure 1

Description

  The present invention includes a master cylinder that generates a brake hydraulic pressure by a driver's braking operation, an electric hydraulic pressure generating unit that generates a brake hydraulic pressure by an electric motor that operates according to the driver's braking operation, and the master cylinder or The present invention relates to a vehicle brake device including a wheel cylinder that operates with a brake hydraulic pressure generated by the electric hydraulic pressure generating means and brakes a wheel, and a control means that controls the operation of the electric hydraulic pressure generating means.

  When the vehicle turns during non-braking, the rotation surface of the brake disc of the disc brake device changes due to the side force acting on the wheels, and the brake disc pushes back the piston of the wheel cylinder to increase the pad clearance (knockback phenomenon) Will occur. A vehicle brake device that compensates for such a knockback phenomenon and maintains an appropriate pad clearance is known from Patent Document 1 below.

The wheel cylinder of the vehicle brake device generates a braking force by driving a piston with an electric motor and a ball screw mechanism. The actual pad clearance detected by the position detection unit of the electric motor depends on the steering angle and the vehicle speed. The drive of the electric motor is controlled so as to coincide with the target pad clearance calculated based on the above.
JP 2005-67247 A

  By the way, the conventional vehicle brake device generates a braking force by driving a piston with an electric motor and a ball screw mechanism. The hydraulic brake device that drives a piston of a wheel cylinder with a brake hydraulic pressure is used as a hydraulic brake device. There was a problem that it was not applicable.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to compensate for an increase in pad clearance of a wheel cylinder due to a knockback phenomenon in a brake device including an electric hydraulic pressure generating means.

  In order to achieve the above object, according to the first aspect of the present invention, a brake is generated by a master cylinder that generates a brake fluid pressure by a driver's braking operation and an electric motor that operates according to the driver's braking operation. Electric hydraulic pressure generating means for generating hydraulic pressure, a wheel cylinder that operates with the brake hydraulic pressure generated by the master cylinder or the electric hydraulic pressure generating means and brakes the wheel, and controls the operation of the electric hydraulic pressure generating means In the vehicle brake device including the control means, the control means operates the electrohydraulic pressure generating means for a predetermined time after a steering angle greater than a predetermined value or a lateral acceleration greater than the predetermined value is detected. A vehicular brake device characterized by generating hydraulic pressure is proposed.

  According to the second aspect of the present invention, in addition to the configuration of the first aspect, the reservoir of the master cylinder and the wheel cylinder communicate with each other when the electric hydraulic pressure generating means is not in operation. Further, a vehicular brake device is proposed in which a one-way valve for preventing release of brake fluid pressure from the wheel cylinder to the reservoir is disposed between the wheel cylinders.

  The slave cylinder 23 of the embodiment corresponds to the electric hydraulic pressure generating means of the present invention, and the front first to third cup seals C3, C4, C5 of the embodiment correspond to the one-way valve of the present invention. The electronic control unit U of the embodiment corresponds to the control means of the present invention.

  According to the configuration of the first aspect, even if a knockback phenomenon occurs in the side force acting on the wheel during turning when the vehicle is not braked and the piston of the wheel cylinder moves backward to increase the pad clearance, a predetermined value is obtained. After the above steering angle or a lateral acceleration of a predetermined value or more is detected, that is, after a side force that causes a knockback phenomenon is generated, the electrohydraulic pressure generating means is operated for a predetermined time to generate the brake hydraulic pressure. Therefore, with the brake fluid pressure, the retracted piston of the wheel cylinder can be advanced to the normal position (position before knockback) to maintain the pad clearance at an appropriate value. It is possible to prevent a decrease in responsiveness of power generation.

  According to the second aspect of the present invention, since the reservoir of the master cylinder and the wheel cylinder are in communication when the electric hydraulic pressure generating means is not operated, the electric hydraulic pressure generating means is operated for a predetermined time so that the brake hydraulic pressure is increased. Even if the pressure is reduced after the pressure is increased, the brake fluid in the reservoir is replenished to the wheel cylinder at the time of the pressure reduction, so that the piston of the wheel cylinder that has returned to the normal position (the position before the occurrence of knockback) has moved back again. It is possible to prevent the clearance from increasing. In addition, a one-way valve that prevents the brake fluid pressure from being released from the wheel cylinder to the reservoir is arranged between the reservoir and the wheel cylinder, so that the brake fluid pressure is prevented from being released to the reservoir during operation of the wheel cylinder. Power can be generated without hindrance.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

  1 to 5 show an embodiment of the present invention. FIG. 1 is a hydraulic circuit diagram in a normal state of a vehicle brake device. FIG. 2 is a hydraulic circuit diagram in an abnormal state corresponding to FIG. 3 is an enlarged sectional view of the slave cylinder, FIG. 4 is a block diagram of the control system, and FIG. 5 is a time chart for explaining the operation of knockback compensation.

  As shown in FIG. 1, the tandem master cylinder 11 includes two hydraulic chambers 13A and 13B that output brake hydraulic pressure in accordance with the pedaling force of the driver stepping on the brake pedal 12, and one hydraulic pressure is provided. The chamber 13A is connected to the wheel cylinders 16 and 17 of the disc brake devices 14 and 15 of, for example, the left front wheel and the right rear wheel via liquid passages Pa, Pb, Pc, Pd, and Pe (first system). The hydraulic chamber 13B is connected to the wheel cylinders 20 and 21 of the disc brake devices 18 and 19 of the right front wheel and the left rear wheel, for example, via the fluid paths Qa, Qb, Qc, Qd, and Qe (second system).

  A shutoff valve 22A, which is a normally open solenoid valve, is disposed between the fluid paths Pa, Pb, and a shutoff valve 22B, which is a normally open solenoid valve, is disposed between the fluid paths Qa, Qb, and the fluid paths Pb, Qb and the fluid path. A slave cylinder 23 is disposed between Pc and Qc, and a VSA (vehicle stability assist) device 24 is disposed between the liquid paths Pc and Qc and the liquid paths Pd and Pe; Qd and Qe.

  A stroke simulator 26 is connected to the liquid paths Ra and Rb branched from the liquid path Qa via a reaction force permission valve 25 which is a normally closed solenoid valve. The stroke simulator 26 is a cylinder 27 slidably fitted with a piston 29 urged by a spring 28, and a hydraulic chamber 30 formed on the side opposite to the spring 28 of the piston 29 communicates with a liquid path Rb. To do.

  The actuator 31 of the slave cylinder 23 includes an electric motor 32, a drive bevel gear 33 provided on the output shaft thereof, a driven bevel gear 34 that meshes with the drive bevel gear 33, and a ball screw mechanism 35 that is operated by the driven bevel gear 34.

  A rear piston 38A and a front piston 38B, which are urged in a backward direction by return springs 37A and 37B, are slidably disposed on the rear and front portions of the cylinder body 36 of the slave cylinder 23, respectively. A rear hydraulic chamber 39A and a front hydraulic chamber 39B are defined on the front surface of the front piston 38B.

  The rear hydraulic chamber 39A communicates with the fluid path Pb via the rear input port 40A, communicates with the fluid path Pc via the rear output port 41A, and the front hydraulic chamber 39B communicates with the front input port 40B. The fluid channel Qb communicates with the fluid channel Qc via the front output port 41B.

  In FIG. 1, when the electric motor 32 is driven in one direction, the rear and front pistons 38A and 38B move forward through the drive bevel gear 33, the driven bevel gear 34, and the ball screw mechanism 35, and enter the liquid paths Pb and Qb. Brake fluid pressure is generated in the rear and front fluid pressure chambers 39A and 39B at the moment when the rear and front input ports 40A and 40B are closed, and the brake fluid pressure is transmitted via the rear and front output ports 41A and 41B. Can be output to the liquid passages Pc and Qc.

  The structure of the VSA device 24 is well known. The first brake actuator 51A for controlling the first system of the disc brake devices 14 and 15 for the left front wheel and the right rear wheel, the disc brake device 18 for the right front wheel and the left rear wheel, A second brake actuator 51B that controls the 19 second system is provided with the same structure.

  Hereinafter, as a representative example, the first brake actuator 51A of the first system of the disc brake devices 14 and 15 for the left front wheel and the right rear wheel will be described.

  The first brake actuator 51A includes a fluid path Pc that communicates with the rear output port 41A of the slave cylinder 23 located on the upstream side, and a fluid path Pd that communicates with the left front wheel and right rear wheel wheel cylinders 16 and 17 located on the downstream side. , Pe.

  The first brake actuator 51A has a common fluid path 52 and a fluid path 53 for the left front wheel and right rear wheel wheel cylinders 16 and 17, and a variable opening disposed between the fluid path Pc and the fluid path 52. A regulator valve 54 composed of a normally open solenoid valve, a check valve 55 arranged in parallel to the regulator valve 54 and allowing the brake fluid to flow from the liquid path Pc side to the liquid path 52 side, and a liquid path 52 and an in-valve 56 made of a normally open solenoid valve having a variable opening disposed between the fluid passage Pe and a brake fluid from the fluid passage Pe side to the fluid passage 52 side which is disposed in parallel to the in-valve 56. A check valve 57 that allows flow, an in-valve 58 that is a normally-open electromagnetic valve with a variable opening disposed between the liquid passage 52 and the liquid passage Pd, and the in-valve 58 in parallel And a check valve 59 that allows the brake fluid to flow from the fluid passage Pd side to the fluid passage 52 side, and a normally closed electromagnetic valve with a variable opening disposed between the fluid passage Pe and the fluid passage 53. A valve 60, an out valve 61 composed of a normally closed electromagnetic valve with a variable opening disposed between the liquid passage Pd and the liquid passage 53, a reservoir 62 connected to the liquid passage 53, and the liquid passage 53 and the liquid passage 52. A check valve 63 disposed between the liquid path 53 side and the liquid path 52 side, and a check valve 63 disposed between the check valve 63 and the liquid path 52 and disposed between the liquid path 53 side and the liquid path 52 side. A suction valve comprising a pump 64 for supplying brake fluid to the motor, an electric motor 65 for driving the pump 64, and a normally closed electromagnetic valve disposed between the check valve 63 and the intermediate position of the pump 64 and the fluid passage Pc. And a 6.

  The electric motor 65 is shared with the pumps 64 and 64 of the first and second brake actuators 51A and 51B. However, dedicated electric motors 65 and 65 are provided for the pumps 64 and 64, respectively. It is also possible to provide it.

  A hydraulic pressure sensor Sa for detecting a brake hydraulic pressure is provided in a hydraulic path Pa extending from one hydraulic pressure chamber 13A of the master cylinder 11, and a brake generated by the slave cylinder 23 in a hydraulic path Pc on one inlet side of the VSA device 24. A hydraulic pressure sensor Sb for detecting hydraulic pressure is provided, and a wheel speed sensor Sc is provided for each of the four wheels.

  As apparent from FIG. 3, the rear hydraulic pressure chamber 39A communicates with the liquid path Pb via the rear input port 40A and the rear supply port 42A, and communicates with the liquid path Pc via the rear output port 41A. The front hydraulic pressure chamber 39B communicates with the liquid path Qb through the front input port 40B and the front first supply port 42B, and also communicates with the liquid path Qc through the front output port 41B.

  A rear first cup seal C1 is provided forward (at the front end of the rear piston 38A so as to exhibit a sealing function during advance), and a rear second cup seal C2 is provided forward at the rear end of the rear piston 38A. A front first cup seal C3 is provided forward at the front end of the front piston 38B, and a front second cup seal C4 is provided rearward at the rear end of the front piston 38B (so as to exhibit a sealing function when moving backward). Is provided. Furthermore, a front-facing front third cup seal C5 is provided at an intermediate portion of the front piston 38B.

  A rear reservoir chamber 38a sandwiched between the rear first and second cup seals C1 and C2 is formed at an intermediate portion of the rear piston 38A, and a rear supply port 42A communicates with the rear reservoir chamber 38a. A front first reservoir chamber 38b sandwiched between front first and third cup seals C3 and C5 is formed at the front of the front piston 38B, and the front first reservoir chamber 38b has a front part first reservoir chamber 38b. One supply port 42B communicates. A front second reservoir chamber 38c sandwiched between the front second and third cup seals C4 and C5 is formed at the rear of the front piston 38B, and the front second reservoir chamber 38c has a front second reservoir chamber 38c. 2 Supply port 43 communicates. The front second supply port 43 communicates with the reservoir 44 of the master cylinder 11 via the liquid path Rc (see FIG. 1).

  The rear hydraulic chamber 39A is sandwiched between the forward rear first cup seal C1 and the rearward front second cup seal C4 to ensure liquid tightness, and the backward fluid leakage from the rear reservoir chamber 38a is forward. It is blocked by the rear second cup seal C2. The front hydraulic chamber 39B is liquid-tight by the forward-facing front first cup seal C3, and the backward liquid leakage from the front first reservoir chamber 38b is prevented by the forward-facing front third cup seal C5. Is done.

  The brake fluid in the front second reservoir chamber 38c communicating with the reservoir 44 of the master cylinder 11 via the front second supply port 43 and the fluid path Rc passes through the second front cup seal C4 that functions as a one-way valve. It can flow into the rear hydraulic chamber 39A and can flow into the front hydraulic chamber 39B via the front third cup seal C5 and the front first cup seal C3 functioning as a one-way valve.

  When the slave cylinder 23 is not operated, the rear first cup seal C1 of the rear piston 38A is positioned immediately behind the rear input port 40A. When the rear piston 38A is slightly advanced, the rear first cup seal C1 is moved to the rear input port 40A. The brake fluid pressure is generated in the rear fluid pressure chamber 39A. When the slave cylinder 23 is not operated, the front first cup seal C3 of the front piston 38B is located immediately after the front input port 40B, and when the front piston 38B slightly advances, the front first cup seal C3 is moved forward. Passes through the front input port 40B, and brake fluid pressure is generated in the front fluid pressure chamber 39B.

  FIG. 4 is a block diagram of the control system of the brake device described in FIG. 1, and in addition to signals from the hydraulic pressure sensors Sa, Sb and wheel speed sensors Sc, a steering angle for detecting the steering angle of the vehicle. The electronic control unit U to which signals from the sensor Sd and the lateral acceleration sensor Se that detects the lateral acceleration of the vehicle are input controls the operation of the shutoff valves 22A and 22B, the VSA device 24, the reaction force permission valve 25, and the electric motor 32. To do.

  Next, the operation of the embodiment of the present invention having the above configuration will be described.

  When the system functions normally, as shown in FIG. 1, the shut-off valves 22A and 22B made of normally open solenoid valves are demagnetized and opened, and the reaction force permission valve 25 made of normally closed solenoid valves is excited. Open the valve. In this state, when the hydraulic pressure sensor Sa provided in the liquid path Pa detects that the driver depresses the brake pedal 12, the electric motor 32 of the slave cylinder 23 is activated, and the rear and front pistons 38A and 38B move forward. Brake hydraulic pressure is generated in the rear and front hydraulic chambers 39A and 39B. This brake hydraulic pressure is transmitted to the wheel cylinders 16, 17; 20, 21 of the disc brake devices 14, 15; 18, 19 via the opened in valves 56, 56; Braking.

  When the rear and front pistons 38A and 38B of the slave cylinder 23 are slightly advanced, the communication between the fluid passages Pb and Qb and the rear and front hydraulic chambers 39A and 39B is cut off, so that the brake generated by the master cylinder 11 occurs. The hydraulic pressure is not transmitted to the disc brake devices 14, 15; At this time, the brake fluid pressure generated in the fluid pressure chamber 13B of the master cylinder 11 is transmitted to the fluid pressure chamber 30 of the stroke simulator 26 via the opened reaction force permission valve 25, and the piston 29 resists the spring 28. Thus, the stroke of the brake pedal 12 can be allowed and a pseudo pedal reaction force can be generated to eliminate the driver's uncomfortable feeling.

  At this time, the operation of the slave cylinder 23 is performed so that the brake fluid pressure detected by the fluid pressure sensor Sb provided in the fluid passage Pc becomes a value corresponding to the brake fluid pressure detected by the fluid pressure sensor Sa provided in the fluid passage Pa. The wheel cylinders 16, 17; 20, 21 can generate a braking force corresponding to the pedaling force applied to the brake pedal 12 by the driver.

  Next, the operation of the VSA device 24 will be described.

  When the driver steps on the brake pedal 11 to perform braking, the electric motor 65 stops operating, the regulator valves 54 and 54 are demagnetized and opened, the suction valves 66 and 66 are demagnetized and closed, The in valves 56, 56; 58, 58 are demagnetized and opened, and the out valves 60, 60; 61, 61 are demagnetized and closed. Accordingly, the brake fluid pressure output from the rear and front output ports 41A and 41B of the slave cylinder 23 in operation passes through the in-valves 56 and 56; 58 and 58 which are opened from the regulator valves 54 and 54, and the wheel cylinders. 16, 17; 20, 21 to brake the four wheels.

  When the driver is not stepping on the brake pedal 11, if the pumps 64, 64 are driven by the electric motor 65 with the suction valves 66, 66 opened while being excited, they pass from the slave cylinder 23 through the suction valves 66, 66. The brake fluid sucked and pressurized by the pumps 64 and 64 is supplied to the regulator valves 54 and 54 and the in valves 56 and 56; 58 and 58. Accordingly, the regulator valves 54, 54 are excited to adjust the opening, thereby adjusting the brake fluid pressure in the fluid passages 52, 52, and the brake valve pressure is opened to a predetermined opening by excitation. By selectively supplying the wheel cylinders 16, 17; 20, 21 via 56; 58, 58, the braking force of the four wheels can be individually controlled even when the driver is not stepping on the brake pedal 11. Can do.

  Therefore, the braking force of the four wheels is individually controlled by the first and second brake actuators 51A and 51B, and the braking force of the inner turning wheel is increased to improve the turning performance, or the braking force of the outer turning wheel is increased to stabilize straight running. Performance can be improved.

  Further, when the driver steps on the brake pedal 11 suddenly to avoid a collision, the brake fluid pressure generated by the slave cylinder 23 is further increased by the pumps 64 and 64, and the wheel is driven by the increased brake fluid pressure. Maximum braking force is generated in the cylinders 16, 17; That is, when the pumps 64 and 64 are driven by the electric motor 65 with the regulator valves 54 and 54 excited and closed, and the suction valves 66 and 66 excited and opened, the brake fluid generated by the slave cylinder 23 is generated. The pressure is sucked into the pumps 64 and 64 through the suction valves 66 and 66, and further supplied to the wheel cylinders 16, 17; 20 and 21 through the in-valves 56, 56; Assisting the driver's braking operation can generate a large braking force for avoiding a collision.

  When the driver depresses the brake pedal 12 and detects, for example, that the left front wheel is in a locking tendency by stepping on the low friction coefficient road based on the output of the wheel speed sensor Sc. One brake valve 51A of the first brake actuator 51A is energized and closed, and one of the out valves 61 is excited and opened, so that the brake fluid pressure of the wheel cylinder 16 of the left front wheel is released to the reservoir 62 and predetermined. Then, the brake fluid pressure of the wheel cylinder 16 of the left front wheel is maintained by demagnetizing and closing the out valve 61. As a result, when the locking tendency of the wheel cylinder 16 of the left front wheel is resolved, the brake fluid pressure from the rear output port 41A of the slave cylinder 23 is opened by demagnetizing the in-valve 58, so that the wheel cylinder 16 of the left front wheel And the braking force is increased by increasing the pressure to a predetermined pressure.

  When the left front wheel becomes locked again due to this pressure increase, by repeating the pressure reduction → holding → pressure increase, the ABS (anti-lock brake) that minimizes the braking distance while suppressing the lock on the left front wheel is repeated.・ System) Control can be performed.

  The ABS control when the left front wheel wheel cylinder 16 tends to lock has been described above. However, the right rear wheel wheel cylinder 17, the right front wheel wheel cylinder 20, and the left rear wheel wheel cylinder 21 tend to lock. The ABS control can be performed in the same manner.

  While the above-described VSA control (including ABS control) is being executed, the shutoff valves 22A and 22B are maintained in the closed state, so that the change in hydraulic pressure due to the operation of the VSA device 24 becomes a kickback and the master cylinder. Transmission from the brake pedal 12 to the brake pedal 12 can be prevented.

  When the power supply fails, as shown in FIG. 2, the shut-off valves 22A and 22B made of normally open solenoid valves are automatically opened, and the reaction force permission valve 25 made of normally closed solenoid valves is automatically turned on. The in-valves 56, 56; 58, 58 consisting of normally-open solenoid valves are automatically opened, and the out-valves 60, 60; 61, 61 consisting of normally-closed solenoid valves are automatically closed. To do. In this state, the brake hydraulic pressure generated in the two hydraulic chambers 13A and 13B of the master cylinder 11 is not absorbed by the stroke simulator 26, and the rear and front hydraulic pressures of the shutoff valves 22A and 22B and the slave cylinder 23 are detected. Passing through the chambers 39A and 39B and the in-valves 56, 56; 58, 58, the wheel cylinders 16, 17; 20, 21 of the disc brake devices 14, 15; 18, 19 of each wheel are operated to generate braking force without any trouble. Can be made.

  By the way, when the vehicle turns at a high speed or turns at a large steering angle, a large side force acts to slightly distort the rotating surface of the wheel, and the brake discs of the disc brake devices 14, 15; In some cases, the pistons of the cylinders 16, 17; When such a state occurs during non-braking, the pistons of the wheel cylinders 16, 17; 20, 21 are slightly pushed into the cylinder bores, and the pistons are in their normal positions (before the knockback occurs) even after the side force disappears. Therefore, a phenomenon (knockback phenomenon) in which the pad clearance of the wheel cylinders 16, 17; 20, 21 is increased occurs. When such a knockback phenomenon occurs, the next time the wheel cylinders 16, 17; 20, 21 are operated, there is a problem that the response of the braking force generation is reduced by the amount corresponding to the increased pad clearance.

  Therefore, as shown in FIG. 5, when the steering angle detected by the steering angle sensor Sd becomes a predetermined value or more, or when the lateral acceleration detected by the lateral acceleration sensor Se becomes a predetermined value or more, the slave cylinder 23 Is operated for a predetermined time, and the rear and front pistons 38A, 38B are moved forward by a predetermined stroke and then moved back to their original positions, so that the brake fluid pressure is applied to the wheel cylinders 16, 17; The piston retracted due to the phenomenon is advanced to the original position.

  The operation amount of the slave cylinder 23 at this time is set according to the steering angle or the lateral acceleration, and the operation amount is such that the wheel cylinder pressure does not rise, that is, the wheel cylinders 16, 17; The size is set so that no drag occurs.

  When the slave cylinder 23 is actuated and the rear and front pistons 38A and 38B move forward and then move back to their original positions, the fluid paths Pc to Pe, Qc to the slave cylinder 23 and the wheel cylinders 16, 17; When Qe is sealed, there is a problem that a negative pressure acts on the wheel cylinders 16, 17; 20, 21, and the piston that has moved forward moves backward again to increase the pad clearance.

  However, the reservoir 44 of the master cylinder 11 communicates with the front second reservoir chamber 38c via the liquid path Rc and the front second supply port 43, and before the front second reservoir chamber 38c functions as a one-way valve. The second cup seal C4, the rear hydraulic pressure chamber 39A, the rear output port 41A and the fluid passages Pc to Pe communicate with the wheel cylinders 16 and 17, and the front second reservoir chamber 38c functions as a one-way valve. The front third cup seal C5, the front first reservoir chamber 38b, the front first cup seal C3 functioning as a one-way valve, the front hydraulic pressure chamber 39B, the front output port 41B, and the liquid paths Qc to Qe Because the brake fluid in the reservoir 44 is replenished to the wheel cylinders 16, 17; It is possible to prevent the pad clearance is increased in.

  During braking in which brake fluid pressure is applied to the wheel cylinders 16, 17; 20, 21, the front first to third cup seals C <b> 3 to C <b> 5 prevent the brake fluid pressure from being released to the reservoir 44. , 17; 20, 21 can generate braking force without any problem.

  The embodiments of the present invention have been described above, but various design changes can be made without departing from the scope of the present invention.

  For example, although the brake device according to the embodiment includes the VSA device 24, the ABS device may be provided instead of the VSA device 24, or may not be provided.

Hydraulic circuit diagram for a normal brake system for vehicles Hydraulic circuit diagram at the time of abnormality corresponding to FIG. Enlarged cross section of slave cylinder Block diagram of control system Time chart explaining the effect of knockback compensation

Explanation of symbols

11 Master cylinder 16 Wheel cylinder 17 Wheel cylinder 20 Wheel cylinder 21 Wheel cylinder 23 Slave cylinder (electric hydraulic pressure generating means)
32 electric motor 44 reservoir C3 front first cup seal (one-way valve)
C4 Front second cup seal (one-way valve)
C5 Front third cup seal (one-way valve)
U Electronic control unit (control means)

Claims (2)

A master cylinder (11) for generating a brake fluid pressure by a driver's braking operation;
Electric hydraulic pressure generating means (23) for generating a brake hydraulic pressure by an electric motor (32) that operates in accordance with a driver's braking operation;
A wheel cylinder (16, 17; 20, 21) that operates with the brake hydraulic pressure generated by the master cylinder (11) or the electric hydraulic pressure generating means (23) to brake the wheel;
Control means (U) for controlling the operation of the electric hydraulic pressure generating means (23);
In a vehicle brake device comprising:
The control means (U) activates the electrohydraulic pressure generating means (23) for a predetermined time to generate a brake hydraulic pressure after a steering angle greater than a predetermined value or a lateral acceleration greater than a predetermined value is detected. Brake device for vehicles characterized by this.   The reservoir (44) of the master cylinder (11) and the wheel cylinder (16, 17; 20, 21) are in communication with each other when the electric hydraulic pressure generating means (23) is not in operation, and the reservoir (44) and Between the wheel cylinders (16, 17; 20, 21), a one-way valve (C3, which prevents release of brake fluid pressure from the wheel cylinders (16, 17; 20, 21) to the reservoir (44)). The vehicle brake device according to claim 1, wherein C4 and C5) are arranged.

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