JP2007112332A - Vehicular brake device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vehicular brake device capable of enhancing the pulsation reduction effect by smoothly allowing the elastic deformation of a seal member to be elastically deformed to a deformation permissible chamber side according to the discharge port side liquid pressure of a hydraulic pump. <P>SOLUTION: An annular seal member 24 is stored in an annular seal groove 22 formed in a cylinder member 20 arranged in and fixed to a pump housing 10 of a hydraulic pump HP1. The liquid pressure on a discharge port 16 side is applied to one side of the seal member 24. An annular deformation permissible chamber 66 is formed on the other side of the seal member 24. The liquid pressure on a suction port 14 side is fed to the deformation permissible chamber 66 by an axial groove 68 formed in an outer circumference of the cylinder member 20 so that the other side surface of the seal member 24, the other side surface of the seal groove 22, and an inner circumferential surface of the pump housing 10 are lubricated with a brake fluid, and the elastic deformation of the seal member 24 to the deformation permissible chamber 66 side is smoothly performed. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a vehicle brake device, and in particular, a master cylinder that generates a hydraulic pressure according to a brake operation, a wheel brake mechanism that includes a wheel cylinder that is operated by a hydraulic pressure supplied from the master cylinder, and the wheel brake. A hydraulic pressure control valve interposed between the wheel cylinder and the master cylinder to at least reduce and re-increase the hydraulic pressure of the wheel cylinder of the mechanism, and brake fluid discharged from the hydraulic pressure control valve temporarily A reservoir for accumulating, a hydraulic pump for recirculating brake fluid in the reservoir between the master cylinder and the hydraulic control valve, and an annular pressure pump on which the hydraulic pressure on the discharge port side of the hydraulic pump is applied to one side A seal member and a part of the seal member that elastically deforms in accordance with the hydraulic pressure on the discharge port side of the hydraulic pump while accommodating the seal member The deformation allowing chamber tolerated relates brake system equipped with an annular seal groove is formed on the other side of the seal member.

  A conventional vehicle brake device of this type is described in Patent Document 1 below. In the vehicle brake device described in Patent Document 1, a plug in which an annular seal member is accommodated in an annular seal groove on the outer periphery is incorporated in a damper hole of the housing to supply hydraulic pressure on the discharge port side of the hydraulic pump. In order to reduce the pulsation of the hydraulic pressure at the discharge port side of the hydraulic pump, a tapered portion is provided on the side surface of the plug seal groove opposite to the damper chamber to form an annular deformation allowance chamber. According to the discharge port side hydraulic pressure of the pressure pump, the seal member is elastically deformed toward the deformation permitting chamber side to reduce pulsation of the discharge port side hydraulic pressure of the hydraulic pump.

JP 2000-177564 A

  However, since the anti-damper chamber side of the seal member is exposed to the atmosphere and is in a dry state, when the seal member is elastically deformed to the deformation permissible chamber side, a damper hole that is a wall surface that forms the surface of the seal member and the deformation permissible chamber Since a relatively large frictional resistance is generated between the peripheral surface and the side of the seal groove, the seal member is elastically deformed according to the hydraulic pressure on the discharge port side of the hydraulic pump, but the amount of deformation is small, and the hydraulic pump The discharge port side hydraulic pressure pulsation reduction effect cannot be obtained sufficiently.

  Therefore, the present invention has an object to increase the elastic deformation amount of the seal member due to the hydraulic pressure on the discharge port side of the hydraulic pump as compared with the conventional device, and to increase the pulsation reduction effect of the hydraulic pressure on the discharge port side of the hydraulic pump. .

  According to a first aspect of the present invention, there is provided a wheel brake mechanism including a master cylinder that generates a hydraulic pressure corresponding to a brake operation, a wheel cylinder that is operated by a hydraulic pressure supplied from the master cylinder, and the wheel. A hydraulic pressure control valve interposed between the wheel cylinder and the master cylinder for at least reducing and re-increasing the hydraulic pressure of the wheel cylinder of the brake mechanism, and the brake fluid discharged from the hydraulic pressure control valve temporarily A hydraulic reservoir for recirculating the brake fluid in the reservoir between the master cylinder and the hydraulic pressure control valve, and a ring in which the hydraulic pressure on the discharge port side of the hydraulic pump acts on one side The seal member and the seal member are accommodated and part of the seal member is allowed to elastically deform according to the hydraulic pressure on the discharge port side of the hydraulic pump. A brake device for a vehicle having an annular seal groove for forming a deformation-permitted chamber on the other side of the seal member, wherein the hydraulic pressure on the suction port side of the hydraulic pump is supplied to the deformation-permitted chamber. To do.

  The vehicle brake device according to claim 1, wherein the vehicle brake device is installed in a pump housing having a cylinder and a suction port and a discharge port that are provided apart from each other in the axial direction of the cylinder. A seal groove is formed on the outer periphery of the cylinder member, and in order to form a deformation allowance chamber, the side surface on the suction port side of both side surfaces of the seal groove is one-half to the depth of the seal groove. It is preferable that it is cut out so that a stepped portion or a tapered portion is formed from the one third position to the radially outer end.

  In the vehicle brake device according to claim 2, as described in claim 3, the cylinder member is press-fitted into the cylinder at a portion adjacent to the suction port side of the seal groove, It is preferable that a groove for communicating the suction port and the deformation allowing chamber is formed.

  Since this invention is comprised as mentioned above, there exist the following effects. That is, in the vehicle brake device according to the first aspect, the surface of the seal member and the wall surface forming the deformation allowance chamber are formed by supplying the suction port side hydraulic pressure of the hydraulic pump to the deformation allowance chamber. Therefore, when the seal member is elastically deformed to the deformation permissible chamber side according to the hydraulic pressure on the discharge port side of the hydraulic pump, the friction resistance between the seal member and the wall surface forming the deformation permissible chamber is the conventional device. Compared to Accordingly, the amount of elastic deformation of the seal member due to the hydraulic pressure on the discharge port side of the hydraulic pump is larger than that of the conventional device, and the effect of reducing the pulsation of the hydraulic pressure on the discharge port side of the hydraulic pump is enhanced.

  In the vehicle brake device according to the second aspect, it is possible to easily form the deformation allowing chamber having an effective volume for reducing the pulsation of the hydraulic pressure on the discharge port side of the hydraulic pump.

  In the vehicle brake device according to the third aspect, the cylinder member can be easily and reliably fixed to the pump housing, and the suction port side hydraulic pressure can be reliably supplied to the deformation allowing chamber.

  Embodiments of the present invention will be described below with reference to the drawings. In the vehicle brake device according to the present embodiment, as shown in FIG. 1, a brake pedal BP as a brake operation member is operatively connected to a known tandem master cylinder MC via a known vacuum booster VB. Yes. That is, when the brake pedal BP is operated, the two front and rear pressure generation chambers inside the master cylinder MC (the pressure generation chambers separated into right and left in FIG. 1, the left is the front and the right is the rear) are large. It is configured so that the hydraulic pressure corresponding to the brake pedal operating force is generated in these pressure generating chambers by being cut off from the atmospheric pressure reservoir RS.

  Of the two pressure chambers before and after the master cylinder MC, the rear pressure generation chamber is the first hydraulic system H1 on the front right wheel brake mechanism FR and rear left wheel brake mechanism RL side, and the front pressure generation chamber is the front left The wheel brake mechanism FL and the rear right wheel brake mechanism RR are connected to the second hydraulic system H2 on the side. In addition, in this embodiment, what is called X piping is comprised, However, It is good also as front and back piping.

  In the first hydraulic system H1, the pressure generation chamber of the master cylinder MC is connected to the wheel cylinder Wfr and the rear left wheel brake of the front right wheel brake mechanism FR via the main hydraulic path MF and the branched hydraulic paths MFr and MF1, respectively. Connected to the wheel cylinder Wrl of the mechanism RL, a normally open proportional solenoid valve SC1 is interposed in the main hydraulic pressure path MF. The pressure generation chamber of the master cylinder MC is connected between check valves CV5 and CV6, which will be described later, via an auxiliary hydraulic pressure path MFc, and a normally closed electromagnetic valve SI1 is interposed in the auxiliary hydraulic pressure path MFc. Has been. Further, in parallel with the proportional solenoid valve SC1, a check valve CV11 that allows the brake fluid to flow downstream (in the direction of the wheel cylinders Wfr and Wrl) and blocks the fluid in the reverse direction is interposed. When the hydraulic pressure generated by the master cylinder MC becomes larger than the hydraulic pressure downstream of the proportional solenoid valve SC1, even if the proportional solenoid valve SC1 is in the closed position by the check valve CV11, the master cylinder Brake fluid can be supplied from the MC to the downstream side of the proportional solenoid valve SC1. The proportional solenoid valve SC1 controls the hydraulic pressure difference between the master cylinder side hydraulic pressure path and the wheel cylinder Wfr and wrl side hydraulic pressure paths to a hydraulic pressure difference corresponding to the supplied current value.

  Furthermore, in the present embodiment, normally open solenoid valves NOfr and NOrl are interposed in the branch hydraulic pressure paths MFr and MFl, respectively. Further, check valves CV1 and CV2 are interposed in parallel with these. The check valves CV1 and CV2 allow the brake fluid to flow in the direction of the master cylinder MC and prevent the brake fluid from flowing in the direction of the wheel cylinders Wfr and Wrl. The check valves CV1 and CV2 The brake fluid in the wheel cylinders Wfr and Wrl is returned to the master cylinder MC and thus to the atmospheric pressure reservoir RS via the proportional solenoid valve SC1 in the open position. Thus, when the brake pedal BP is released, the hydraulic pressure in the wheel cylinders Wfr and Wrl can quickly follow the decrease in hydraulic pressure on the master cylinder MC side. Further, normally-closed electromagnetic valves NCfr and NCrl are interposed in the discharge-side branch hydraulic pressure paths RFr and RFl connected to the wheel cylinders Wfr and Wrl, and the branch hydraulic pressure paths RFr and RFl merge. The discharge hydraulic pressure channel RF is connected to the reservoir RS1. This reservoir RS1 is provided separately from the atmospheric pressure reservoir RS of the master cylinder MC, and can also be referred to as an accumulator. The reservoir RS1 includes a piston and a spring so as to be able to temporarily store brake fluid having a capacity necessary for various controls. It is configured.

  The hydraulic pump HP1 interposed in the first hydraulic system H1 has a suction port connected to a communication path between the master cylinder MC and the proportional solenoid valve SC1 via the electromagnetic valve SI1, and the hydraulic pump HP1 The discharge port is connected to a communication path between the proportional solenoid valve SC1 and the solenoid valves NOfr and NOrl via a check valve CV7. A reservoir RS1 is connected to the suction port of the hydraulic pump HP1 via check valves CV5 and CV6. The hydraulic pump HP1 is driven by a single electric motor M together with the hydraulic pump HP2, and is configured to suck in brake fluid from the suction port, boost the pressure, and output the pressure from the discharge port. The electric motor M is driven and controlled by the electronic control unit ECU1.

  The master cylinder MC is connected in communication between the check valve CV5 and the check valve CV6 on the suction port side of the hydraulic pump HP1 via the auxiliary hydraulic pressure path MFc and the electromagnetic valve SI1 interposed therein. Yes. The check valve CV5 prevents the brake fluid from flowing into the reservoir RS1 and allows the fluid to flow in the reverse direction. In the solenoid valve SI1, communication between the master cylinder MC and the suction port of the hydraulic pump HP1 is cut off at the normal closed position shown in FIG. 1, and communication between the master cylinder MC and the suction port of the hydraulic pump HP1 is established at the open position. To be switched.

  The proportional solenoid valve SC1, solenoid valve SI1, solenoid valves NOfr and NOrl, and solenoid valves NCfr and NCrl are driven and controlled by the electronic control unit ECU1, and the hydraulic pressures in the wheel cylinders Wfr and Wrl are adjusted.

  Similarly in the hydraulic system H2, the normally open type proportional solenoid valve SC2, the normally closed type solenoid valve SI2, the reservoir RS2, the normally open type solenoid valves NOfl and NOrr, and the normally closed type solenoid valves NCfl and NCrr. , Check valves CV3, CV4, CV8 to CV10, and check valve CV12 are arranged. The hydraulic pump HP2 is driven by the electric motor M together with the hydraulic pump HP1. The proportional solenoid valve SC2, the solenoid valve SI2, the solenoid valves NOfl and NOrr, and the solenoid valves NCfl and NCrr are driven and controlled by the electronic control unit ECU1, and the hydraulic pressures in the wheel cylinders Wfl and Wrr are adjusted.

  Note that a pair of solenoid valves NOfr and NCfr, a pair of solenoid valves NOrl and NCrl, a pair of solenoid valves NOfl and NCfl, and a pair of solenoid valves NOrr and NCrr correspond to the hydraulic control valves according to claim 1, respectively.

  The electronic control unit ECU1 detects an output signal of a front right wheel speed sensor, a front left wheel speed sensor, a rear right wheel speed sensor, a rear left wheel speed sensor not shown, and whether or not the brake pedal BP is operated. An anti-lock control that adjusts the hydraulic pressure of the wheel cylinder so that the brake slip amount of the wheel does not become excessive during braking of the vehicle, and when the vehicle starts In addition, traction control is performed to supply and adjust the hydraulic pressure to the wheel cylinder so that the driving slip amount of the driving wheel does not become excessive during acceleration.

  In the vehicular brake device configured as described above, during normal times, each electromagnetic valve is in the normal position shown in FIG. 1 and the electric motor M is stopped. When the brake pedal BP is operated in this normal state, the vacuum booster VB is activated to operate the master cylinder MC. The master cylinder MC generates a hydraulic pressure corresponding to the brake pedal operating force in two hydraulic pressure generation chambers inside and behind the master cylinder MC, and outputs the hydraulic pressure to the hydraulic systems H1 and H2. The hydraulic pressure output from the master cylinder MC to the hydraulic pressure system H1 is supplied to the wheel cylinder Wfr of the wheel brake mechanism FR via the proportional solenoid valve SC1 and the solenoid valve NOfr, and the proportional solenoid valve SC1 and the solenoid valve NOrl. To the wheel cylinder Wrl of the wheel brake mechanism RL. At the same time, the hydraulic pressure output from the master cylinder MC to the hydraulic pressure system H2 is supplied to the wheel cylinder Wfl of the wheel brake mechanism FL via the proportional solenoid valve SC2 and the solenoid valve NOfl, and the proportional solenoid valve SC2 and It is supplied to the wheel cylinder Wrr of the wheel brake mechanism RR via the electromagnetic valve NOrr. Accordingly, the wheel brake mechanisms FR, FL, RR, and RL are actuated to apply brake torque to the front right wheel, front left wheel, rear right wheel, and rear left wheel of the vehicle, and the vehicle is braked.

  When the operated brake pedal BP is released, the vacuum booster VB returns to the normal state, thereby returning the master cylinder MC to the normal state, and the hydraulic system from the two pressure generation chambers inside and behind the master cylinder. The hydraulic pressure output to H1 and H2 decreases to atmospheric pressure. Accordingly, the hydraulic pressures of the wheel cylinders Wfr, Wrl, Wfl, Wrr are also reduced to atmospheric pressure, the wheel brake mechanisms FR, FL, RR, RL are returned to the normal state, and the braking of the vehicle is finished.

  Next, antilock control will be described. When braking the vehicle, the electronic control unit ECU1 determines whether or not the braking slip amount is likely to be excessive for each wheel based on the output signal of each wheel speed sensor. When the amount is likely to be excessive, the solenoid valve NOfr is switched from the normal open position to the closed position and the solenoid valve NCfr is switched from the normal close position to the open position, and at the same time, the motor M is started. As a result, the brake fluid in the wheel cylinder Wfr is discharged to the reservoir RS1 via the solenoid valve NCfr, the fluid pressure in the wheel cylinder Wfr is reduced, and the brake torque applied by the front right wheel brake mechanism FR to the front right wheel is reduced. Therefore, the braking slip amount of the front right wheel is reduced. The brake fluid discharged from the wheel cylinder Wfr to the reservoir RS1 via the solenoid valve NCfr is driven between the proportional solenoid valve SC1 and the solenoid valves NOfr and NOrl by driving the hydraulic pump HP1 by the motor M. It is returned to the passage and further returned to the rear pressure generating chamber of the master cylinder MC via the proportional solenoid valve SC1.

  When the braking slip amount of the front right wheel is sufficiently reduced as described above, the electronic control unit ECU1 switches the electromagnetic valve NCfr from the open position to the closed position and switches the electromagnetic valve NOfr from the closed position to the open position. As a result, the brake fluid is supplied from the master cylinder MC to the wheel cylinder Wfr, the hydraulic pressure in the wheel cylinder Wfr is increased again, and the brake torque applied to the front right wheel by the front right wheel brake mechanism FR increases. The braking slip amount of the wheel increases. When the braking slip amount of the front right wheel approaches the excessive braking slip amount, the electronic control unit ECU1 switches the electromagnetic valve NOfr from the open position to the closed position, so that the hydraulic pressure in the wheel cylinder Wfr is maintained.

  If the braking slip amount of the front right wheel increases while the hydraulic pressure of the wheel cylinder Wfr is maintained as described above, and the slip amount is likely to become excessive again, the electronic control unit ECU1 switches the electromagnetic valve NOfr on. The solenoid valve NCfr is switched from the closed position to the open position while switching from the open position to the closed position. As a result, the brake fluid in the wheel cylinder Wfr is discharged to the reservoir RS1 via the solenoid valve NCfr, the fluid pressure in the wheel cylinder Wfr is reduced, and the brake torque applied by the front right wheel brake mechanism FR to the front right wheel is reduced. Therefore, the braking slip amount of the front right wheel is reduced.

  As described above, the electronic control unit ECU1 switches the solenoid valves NOfr and NCfr between the two positions according to the braking slip amount of the front right wheel during vehicle braking, and operates the hydraulic pump HP1 with the electric motor M. As a result, the hydraulic pressure of the wheel cylinder Wfr is switched and adjusted between reduced pressure, increased pressure, and held, so that an excessive braking slip amount of the front right wheel during vehicle braking is avoided.

  When the braking slip amount of the front left wheel during vehicle braking becomes excessive, the electronic control unit ECU1 causes the solenoid valves NOfl and NCfl to move between two positions according to the braking slip amount of the front left wheel during vehicle braking. By switching and operating the hydraulic pump HP2 with the electric motor M, the hydraulic pressure of the wheel cylinder Wfl is switched and adjusted between pressure reduction, re-pressure increase and holding, and is avoided.

  When the braking slip amount of the rear right wheel during vehicle braking becomes excessive, the electronic control unit ECU1 causes the solenoid valves NOrr and NCrr to move between the two positions according to the braking slip amount of the rear right wheel during vehicle braking. By switching and operating the hydraulic pump HP2 with the electric motor M, the hydraulic pressure of the wheel cylinder Wrr is switched and adjusted between pressure reduction, re-pressure increase and holding, and is avoided. Then, the braking slip amount of the rear left wheel during vehicle braking becomes excessive because the electronic control unit ECU1 sets the solenoid valves NOrl and NCrl in two positions according to the braking slip amount of the rear left wheel during vehicle braking. By operating the hydraulic pump HP1 with the electric motor M, the hydraulic pressure of the wheel cylinder Wrl can be avoided by being adjusted by switching between depressurization, re-increase and hold.

  Next, traction control for avoiding an excessive drive slip amount on the drive wheels when the vehicle starts or accelerates will be described. The vehicle brake device shown in FIG. 1 is applied to a front wheel drive vehicle. When the vehicle starts or accelerates, generally, the brake pedal BP is not operated, each solenoid valve is in the normal position shown in FIG. 1, and the electric motor M is stopped. For example, when the driving slip amount of the front right wheel of the vehicle is likely to become excessive, the electronic control unit ECU1 switches the proportional solenoid valve SC1 from the fully open position to the fully closed position and switches the solenoid valve SI1 from the closed position to the open position. Then, the electric motor M is started to drive the hydraulic pumps HP1 and HP2. Thereby, the hydraulic pump HP1 sucks the brake fluid in the atmospheric pressure reservoir RS from the suction port via the master cylinder MC and the electromagnetic valve SI1, raises the pressure, and discharges it from the discharge port. Since the brake fluid discharged from the hydraulic pump HP1 is supplied to the wheel cylinder Wfr via the solenoid valve NOfr, the hydraulic pressure of the wheel cylinder Wfr rises and the wheel brake mechanism FR operates to apply brake torque to the front right wheel. In addition, an increase in the wheel speed of the front right wheel is suppressed, and an increase in the drive slip amount of the front right wheel is suppressed. Then, the proportional solenoid valve SC1 is opened by the electronic control unit ECU1, and the hydraulic pressure of the wheel cylinder Wfr is adjusted by adjusting the opening of the proportional solenoid valve SC1, so that the driving slip amount of the front right wheel is appropriate. It adjusts so that it may become a driving slip amount.

  When the driving slip amount of the front left wheel of the vehicle is likely to become excessive, the electronic control unit ECU1 switches the proportional solenoid valve SC2 from the fully open position to the fully closed position and switches the solenoid valve SI2 from the closed position to the open position. Then, the electric motor M is started to drive the hydraulic pumps HP1 and HP2. As a result, the hydraulic pump HP2 sucks the brake fluid in the atmospheric pressure reservoir RS from the suction port via the master cylinder MC and the electromagnetic valve SI2, raises the pressure, and discharges it from the discharge port. Since the brake fluid discharged from the hydraulic pump HP2 is supplied to the wheel cylinder Wfl via the solenoid valve NOfl, the hydraulic pressure of the wheel cylinder Wfl rises and the wheel brake mechanism FL operates to apply brake torque to the front left wheel. In addition, an increase in the wheel speed of the front left wheel is suppressed, and an increase in the driving slip amount of the front left wheel is suppressed. Then, the proportional solenoid valve SC2 is opened by the electronic control unit ECU1, and the hydraulic pressure of the wheel cylinder Wfl is adjusted by adjusting the opening of the proportional solenoid valve SC2, so that the driving slip amount of the front left wheel is appropriate. It adjusts so that it may become a driving slip amount.

  FIG. 2 is a cross-sectional view showing a detailed structure of the hydraulic pump HP1 shown in FIG. FIG. 3 is an enlarged view of a main part of FIG. Since the configuration of the hydraulic pump HP2 shown in FIG. 1 is the same as that of the hydraulic pump HP1, only the hydraulic pump HP1 will be described. In FIG. 2, the pump housing 10 has a stepped cylinder 12, and a suction port 14 and a discharge port 16 that are provided at intervals in the axial direction of the stepped cylinder 12 and open to the stepped cylinder 12. Yes. The plug 18 for closing the left end opening of the stepped cylinder 12 is fixed to the pump housing 10 in a liquid-tight manner by caulking the pump housing 10.

  The cylinder member 20 located on the right side of the plug 18 in the stepped cylinder 12 is press-fitted into the stepped cylinder 12 by a flange portion 20a adjacent to the right side of the annular seal groove 22 formed on the outer periphery. It is fixed to the pump housing 10. An annular seal member 24 accommodated in the seal groove 22 seals between the outer periphery of the cylinder member 20 and the pump housing 10. The cylinder member 20 is formed with a cylinder 26 that is open at the right end and closed at the left end, and a stepped through hole 30 that connects the cylinder 26 to a discharge chamber 28 between the plug 18 and the cylinder member 20. An intermediate portion of the stepped through hole 30 is formed in the valve seat 30 a, and a spherical valve body 34 seated on the valve seat 30 a by the urging force of the compression coil spring 32 is in the left portion of the stepped through hole 30. It is arranged. The valve seat 30a, the compression coil spring 32 and the valve body 34 constitute a check valve CV7 shown in FIG. The discharge chamber 28 is always in communication with the discharge port 16.

  The piston 36 installed in the right portion of the stepped cylinder 12 includes a right first member 38 and a left second member 40. The right end portion of the first member 38 is slidably fitted to the right end portion of the stepped cylinder 12. An annular seal member 42 accommodated in an annular seal groove formed on the outer periphery of the right end portion of the first member 38 seals between the pump housing 10 and the outer periphery of the piston 36. An annular sliding ring groove 44 formed in the first member 38 accommodates an inner peripheral portion of a sliding ring 46 that is liquid-tightly and slidably engaged with the stepped cylinder 12 at the outer periphery. As a result, a supply chamber 48 is formed on the right side of the sliding ring 46.

  The passage 50 formed in the first member 38 always communicates the bottom portion of the sliding ring groove 44 and the supply chamber 48, and always communicates the supply chamber 48 and the right end of the through hole 52 formed in the second member 40. To do. The axial dimension of the sliding ring groove 44 is slightly larger than the axial dimension of the inner peripheral portion of the sliding ring 46, and the diameter of the bottom surface of the sliding ring groove 44 is smaller than the inner peripheral diameter of the sliding ring 46. . Thus, as shown in FIG. 2, when the right end of the inner peripheral portion of the sliding ring 46 is in contact with the right side surface of the sliding ring groove 44, the bottom surface of the sliding ring groove 44 and the inner periphery of the sliding ring 46 are obtained. And the outer periphery of the right end portion of the cylinder member 20 through an annular passage formed between the left side surface of the sliding ring groove 44 and the left end of the sliding ring 46. The annular suction chamber 54 and the passage 50 of the piston 36 communicate with each other. The suction chamber 54 is always in communication with the suction port 14.

  The left end portion of the first member 38 of the piston 36 and the second member 40 are slidably fitted into the cylinder 26 of the cylinder member 20, thereby forming a pump chamber 56 in the cylinder 26. In the pump chamber 56, a compression coil spring 58 for pushing the piston 36 to the right, a spherical valve body 60 assembled to the second member 40 of the piston 36, and the valve body 60 through the through hole A compression coil spring 64 for seating on a valve seat 62 formed so as to be adjacent to the left end of 52 is installed. The valve body 60, the compression coil spring 64, and the valve seat 62 constitute a check valve CV6 shown in FIG.

  The hydraulic pressure on the discharge port 16 side always acts on the left side of the seal member 24. As shown in FIG. 3, the right side surface of the seal groove 22 has an outer diameter side portion located radially outward from a third position of the depth of the seal groove. The deformable chamber 66 is formed by cutting so as to form a stepped portion 22a that is biased toward the surface. An axial groove 68 that always communicates the suction chamber 54 and the deformation allowing chamber 66 is formed in the flange portion 20 a of the cylinder member 20. A plurality of the axial grooves 68 are formed at intervals in the circumferential direction. Thus, the fluid pressure on the suction port 14 side is constantly supplied to the deformation allowing chamber 66. The radial dimension of the stepped portion 22a is one half or one third of the depth of the seal groove 22.

  The right end surface of the piston 36 is engaged with an eccentric cam 70 driven by the electric motor M shown in FIG. 1, is pushed leftward by the eccentric cam 70, and is pushed rightward by the compression coil spring 58. FIG. 2 shows a state where the piston 36 is located at the top dead center. The piston 36 is pushed rightward by the compression coil spring 58 in response to the rightward sliding of the piston 36 by the rotation of the eccentric cam. Moved. That is, the piston 36 slides toward the bottom dead center. When the piston 36 is pushed to the right from the position of FIG. 2, the left side surface of the sliding ring groove 44 is in the inner peripheral portion of the sliding ring 46 that is stationary due to sliding resistance with the pump housing 10. Contact between the left end and communication between the suction chamber 54 and the passage 50 is blocked. In the suction stroke in which the piston 36 is continuously pushed toward the bottom dead center, the volume of the supply chamber 48 is reduced by the sliding ring 46 sliding to the right integrally with the piston 36, and the piston 36 Since the volume of the pump chamber 56 increases due to the sliding, the brake fluid in the supply chamber 48 flows through the passage 50 and the through hole 52 and opens the check valve CV6 to flow into the pump chamber 56.

  In the discharge stroke in which the piston 36 slides toward the top dead center after the sliding of the piston 36 reaches the bottom dead center, the volume of the pump chamber 56 decreases according to the sliding of the piston 36. The brake fluid in the pump chamber 56 is pressurized to open the check valve CV7 and flows into the discharge chamber 28. Further, the left side surface of the sliding ring groove 44 of the piston 36 is separated from the inner peripheral portion of the sliding ring 46 which is stationary due to the sliding resistance with the pump housing 10 and slides on the left end of the sliding ring 46. A passage is formed between the left side surface of the ring groove 44 and the suction chamber 54 and the passage 50 communicate with each other again. Then, as the piston 36 continues to slide toward the top dead center, the sliding ring 46 slides integrally with the piston 36 and the volume of the supply chamber 48 increases, so that the brake in the suction chamber 54 is increased. Liquid is drawn into the supply chamber 48 through the passage 50.

  Thus, the brake fluid is pumped from the suction port 14 to the discharge port 16 by the piston 36 repeating the suction stroke from the top dead center to the bottom dead center and the discharge stroke from the bottom dead center to the top dead center. At this time, pulsation occurs in the hydraulic pressure on the discharge port 16 side, but when the hydraulic pressure on the discharge port 16 side rises, a part of the seal member 24 is connected to the hydraulic pressure on the discharge port 16 side and the suction port 14 side. The deformation permitting chamber is elastically deformed into the deformation permitting chamber 66 due to the hydraulic pressure difference with the hydraulic pressure, and when the hydraulic pressure on the discharge port side of a part of the seal member 24 elastically deformed into the deformation permitting chamber 66 is lowered. 66 Restore outside. Thereby, the pulsation of the hydraulic pressure on the discharge port side is reduced. In the present embodiment, in accordance with the present invention, the hydraulic pressure on the suction port 14 side is supplied to the deformation allowing chamber 66, and the surface of the seal member 24, the side surface of the seal groove 22, and the stepped cylinder 12 forming the deformation allowing chamber 66. Since the inner peripheral surface is lubricated with the brake fluid, the elastic deformation of the seal member 24 toward the deformation permitting chamber 66 and the restoration thereof are smoothly performed, and thus a good pulsation reducing effect can be obtained.

  FIG. 4 is an enlarged view of a main part of an embodiment different from the embodiment shown in FIGS. 2 and 3 of the hydraulic pump. In the present embodiment, on the right side surface of the seal groove 22, the outer diameter side portion located radially outward from the one-third position of the depth of the seal groove 22 is formed with a tapered portion 22 b. The deformation allowing chamber 66 is formed by cutting. The deformation permitting chamber 66 is supplied with hydraulic pressure on the suction port 14 side through a groove 68 formed in the cylinder member 20. Therefore, also in this embodiment, since the surface forming the deformation allowance chamber 66 is lubricated by the brake fluid, the seal member 24 can be smoothly and repeatedly elastically deformed according to the pulsation of the discharge port 16 side hydraulic pressure. A pulsation reducing effect can be obtained.

It is a figure which shows schematic structure of embodiment of this invention. It is sectional drawing which shows the detailed structure of embodiment of the pump shown in FIG. It is an enlarged view of the principal part of FIG. It is an enlarged view of the principal part of embodiment different from embodiment of FIG.

Explanation of symbols

BP ... Brake pedal (brake operation member)
MC: Master cylinder FR, FL, RL, RR ... Wheel brake mechanism Wfr, Wfl, Wrl, Wrr ... Wheel cylinder NOfr, NCfr ... Solenoid valve (hydraulic pressure control valve)
RS1, RS2 ... Reservoir HP1, HP2 ... Hydraulic pump 14 ... Suction port 16 ... Discharge port 20 ... Pump housing 22 ... Seal groove 24 ... Seal member 66 ... Deformable chamber

Claims (3)

  A master cylinder that generates a hydraulic pressure in accordance with a brake operation, a wheel brake mechanism that includes a wheel cylinder that is operated by a hydraulic pressure supplied from the master cylinder, and at least reduces a hydraulic pressure of the wheel cylinder of the wheel brake mechanism; A hydraulic pressure control valve interposed between the wheel cylinder and the master cylinder for re-increasing pressure, a reservoir for temporarily storing brake fluid discharged from the hydraulic pressure control valve, and a brake in the reservoir A hydraulic pump for causing liquid to flow back between the master cylinder and the hydraulic pressure control valve, an annular seal member in which the hydraulic pressure on the discharge port side of the hydraulic pump acts on one side, and the seal member And a deformation permitting chamber for allowing a part of the seal member to elastically deform in accordance with the hydraulic pressure on the discharge port side of the hydraulic pump. A vehicle brake device having an annular seal groove formed on the other side of the control member, wherein the hydraulic pressure on the suction port side of the hydraulic pump is supplied to the deformation allowing chamber. Brake device.   2. The vehicle brake device according to claim 1, wherein the seal is provided on an outer periphery of a cylinder member installed in a pump housing having a cylinder and a suction port and a discharge port that are spaced apart in the axial direction of the cylinder. A groove is formed, and in order to form the deformation allowing chamber, the side surface on the suction port side of both side surfaces of the seal groove is one half or one third of the depth of the seal groove. A vehicular brake device that is cut out so that a stepped portion or a tapered portion is formed from a position to a radially outer end. 3. The vehicle brake device according to claim 2, wherein the cylinder member is press-fitted into the cylinder at a portion adjacent to the suction port side of the seal groove, and the suction port and the deformation allowance are included in the portion. A vehicle brake device characterized in that a groove communicating with the chamber is formed.