WO2017179496A1

WO2017179496A1 - Brake device and plunger pump

Info

Publication number: WO2017179496A1
Application number: PCT/JP2017/014443
Authority: WO
Inventors: 淳喜大平; 雅記御簾納; 千春中澤
Original assignee: 日立オートモティブシステムズ株式会社
Priority date: 2016-04-14
Filing date: 2017-04-07
Publication date: 2017-10-19
Also published as: JP2017190066A

Abstract

Provided is a plunger pump capable of achieving minimization of energy loss. This plunger pump comprises a cylinder, a piston, and a seal member. The piston is movably housed within the cylinder. The seal member partitions the interior of the cylinder in the moving axis direction of the piston. The inner periphery of the seal member is brought into partial contact with the outer periphery of the piston.

Description

Brake device and plunger pump

The present invention relates to a plunger pump.

Generally, a plunger pump includes a seal member that separates the inside of a cylinder in the direction of a moving axis of a piston (for example, Patent Document 1).

Special table 2013-527899 gazette

The energy loss could not be suppressed with the above plunger pump.

In the plunger pump according to one embodiment of the present invention, the seal member partially contacts the surface of the member on which the seal member is mounted.

Therefore, according to one embodiment of the present invention, energy loss can be suppressed.

1 shows a schematic configuration of a brake system 1 of an embodiment. It is a perspective view of the housing 6 of the embodiment. FIG. 3 is a cross-sectional view of a second unit 1B of the embodiment. FIG. 4 is an enlarged view of a cross section of a pump section 7A in FIG. FIG. 4 is a perspective view of a cross section of a pump section 7A in FIG. FIG. 5 is an exploded perspective view of some components in the pump unit 7A of the first embodiment. FIG. 5 is an exploded perspective view of some components in the pump unit 7A of the first embodiment. FIG. 4 shows the cylinder 71, the piston 75, and the third seal member 793 of the first embodiment in the cross-sectional view taken along the line VIII-VIII of FIG. The piston 75 and the third seal member 793 of the first embodiment are shown in the VIII-VIII sectional view of FIG. FIG. 6 is an exploded perspective view of some components in a pump unit 7A of a second embodiment. FIG. 4 shows a cylinder 71, a piston 75, and a third seal member 793 of the second embodiment in the cross-sectional view taken along the line VIII-VIII of FIG. FIG. 9 is an exploded perspective view of some components in a pump unit 7A of a third embodiment. FIG. 4 shows a cylinder 71, a piston 75, and a third seal member 793 of the third embodiment in the cross-sectional view taken along the line VIII-VIII of FIG. FIG. 10 is an exploded perspective view of some components in a pump unit 7A of a fourth embodiment. FIG. 4 shows a cylinder 71, a piston 75, and a third seal member 793 of the fourth embodiment in the cross-sectional view taken along the line VIII-VIII of FIG. FIG. 10 is an exploded perspective view of some components in a pump unit 7A of a fifth embodiment. FIG. 4 shows a cylinder 71, a piston 75, and a third seal member 793 of the fifth embodiment in the VIII-VIII sectional view of FIG. FIG. 10 is an exploded perspective view of some components in a pump unit 7A of a sixth embodiment. FIG. 4 shows a cylinder 71, a piston 75, and a third seal member 793 of the sixth embodiment in the XIX-IXXIX sectional view of FIG. FIG. 4 shows a piston 75 and a third seal member 793 of the sixth embodiment in the cross-sectional view taken along the line VIII-VIII of FIG. FIG. 10 is an exploded perspective view of some components in a pump unit 7A of a seventh embodiment. FIG. 8 is an enlarged view of an end portion of a piston 75, a valve case 76, a first ball 771, a first spring 781, and a third seal member 793 in the cross section of the pump portion 7A in FIG. Part XXIII in FIG. 22 is shown enlarged. FIG. 20 is an exploded perspective view of some components in a pump unit 7A of an eighth embodiment. FIG. 25 is an enlarged perspective view showing a part 794 (third seal member 793 and valve case 76) of FIG. FIG. 25 is a perspective view of the component 794 in FIG. 24 as viewed from the Z axis positive direction side.

Hereinafter, modes for carrying out the present invention will be described with reference to the drawings.

[First embodiment]
First, the configuration will be described. The brake system 1 shown in FIG. 1 is a vehicle equipped with only an internal combustion engine (engine) as a prime mover for driving wheels, a hybrid vehicle equipped with an electric motor (generator) in addition to the internal combustion engine, This is a hydraulic brake system that can be mounted on an electric vehicle equipped with only a motor. The system 1 includes a first unit 1A and a second unit 1B. FIG. 1 shows a hydraulic circuit of the second unit 1B together with a cross section of the first unit 1A. For convenience of explanation, the x axis is provided in the moving axis direction of the piston 41 of the master cylinder 4, and the side on which the piston 41 moves in response to the depression operation of the brake pedal 100 is positive. The first unit 1A is connected to the brake pedal 100 via a push rod 100a. The first unit 1A and the second unit 1B are installed in the engine compartment of the vehicle and are connected to each other by a plurality of pipes 10. The plurality of pipes 10 include a master cylinder pipe 10M (primary pipe 10MP, secondary pipe 10MS), a suction pipe 10R, and a back pressure pipe 10X. The wheel cylinder 101 and the second unit 1B of the left front wheel FL, the right front wheel FR, the left rear wheel RL, and the right rear wheel RR of the vehicle are connected to each other by a wheel cylinder pipe 10W. The pipes 10M, 10W, and 10X are metal brake pipes, and the pipe 10R is a rubber hose. The system 1 supplies the brake fluid as hydraulic fluid to the wheel cylinder 101 and generates the wheel cylinder hydraulic pressure (brake hydraulic pressure), thereby applying the friction braking force (hydraulic braking force) to each wheel FL to RR. . System 1 has two brake pipes (primary P system and secondary S system). The piping type is X piping, but front and rear piping may be adopted. In order to distinguish a member corresponding to the P system and a member corresponding to the S system, the suffixes P and S are added to the end of each symbol.

The first unit 1A has a reservoir tank 2, a housing 3, a master cylinder 4, a stroke simulator 5, and a stroke sensor 91. The reservoir tank 2 is a brake fluid source that stores brake fluid, and is opened to atmospheric pressure. The reservoir tank 2 is installed in the housing 3. The reservoir tank 2 has a first partition wall 21 and a second partition wall 22. The partition walls 21 and 22 extend from the bottom of the reservoir tank 2 to a predetermined height, and divide the bottom of the reservoir tank 2 into three chambers. These three chambers have

first chambers

23P and 23S and a second chamber 23R. The second chamber 23R includes a liquid level sensor 24.

The housing 3 accommodates (internally) the master cylinder 4 and the stroke simulator 5 therein. The x-axis negative direction side of the housing 3 is fixed to the dash panel on the vehicle body side with bolts or the like. The housing 3 includes a first cylinder 30, a second cylinder 31, a replenishment liquid path 32, a supply liquid path 33, a positive pressure liquid path 34, a back pressure liquid path 35, a supply port 36, and a back pressure port. 37. The ports 36 and 37 open on the outer surface of the housing 3. The first cylinder 30 extends in the x-axis direction. The cylinder 30 has two seal grooves 301 and 302 and one supply port 303 on both sides in the x-axis direction (for each of the P and S systems). The grooves 301 and 302 and the port 303 have an annular shape extending in the direction around the axis of the cylinder 30. The port 303 is between the grooves 301 and 302. The second cylinder 31 extends in the x-axis direction, and is arranged coaxially with the first cylinder 30 on the x-axis positive direction side of the cylinder 30. The cylinder 31 has a small diameter portion 311 on the x axis negative direction side and a large diameter portion 312 on the x axis positive direction side. The small diameter portion 311 has two

seal grooves

313 and 314. The

grooves

313 and 314 are annular extending in the direction around the axis of the cylinder 31. The replenishment liquid path 32 connects the replenishment port 303 and the

first chambers

23P and 23S. The supply liquid path 33 connects the first cylinder 30 and the supply port 36. The positive pressure liquid passage 34 connects the first cylinder 30 and the small diameter portion 311. The back pressure liquid path 35 connects the large diameter portion 312 and the back pressure port 37. One end of the master cylinder pipe 10M is connected to the supply port 36. One end of a back pressure pipe 10X is connected to the back pressure port 37.

The master cylinder 4 is a first hydraulic pressure source that operates according to the operation of the brake pedal 100 by the driver and can supply hydraulic fluid pressure to the wheel cylinder 101. The master cylinder 4 has a piston 41 and a spring unit 42 for each of the P and S systems. The master cylinder 4 is a tandem type, and has, as a piston 41, a primary piston 41P connected to the push rod 100a and a free piston type secondary piston 41S in series. The piston 41 has a bottomed cylindrical shape, and a supply hole 410 passes through the peripheral wall of the piston 41. The piston 41 is accommodated in the cylinder 30 and can move in the x-axis direction along the inner peripheral surface of the cylinder 30. The stroke sensor 91 detects the movement amount (pedal stroke) of the primary piston 41P in the x-axis direction. The piston 41 defines a hydraulic chamber 40. In the cylinder 30, a primary chamber 40P is defined between the primary piston 41P and the secondary piston 41S, and a secondary chamber 40S is defined between the secondary piston 41S and the x-axis positive direction end of the cylinder 30. A supply liquid path 33 is always open in the chamber 40. A spring unit 42 is accommodated in the hydraulic chamber 40. The spring unit 42 includes a spring 420, a first retainer 421, a second retainer 422, and a stopper 423. The spring 420 is a compression coil spring, and both ends thereof are held by the retainers 421 and 422, respectively. The spring 420 has a maximum axial length limited by the stopper 423, is in a state of being constantly compressed, and can be compressed and elastically deformed within a predetermined amount in the axial direction. The spring 420 functions as a return spring that constantly biases the piston 41 in the negative x-axis direction. Seal members 431 and 432 as rod seals are fitted in the seal grooves 301 and 302, respectively. The seal members 431 and 432 are annular and have a U-shaped cross section. The seal member 432 on the x axis positive direction side suppresses the flow of brake fluid from the hydraulic pressure chamber 40 side to the replenishment port 303 side on the outer peripheral side of the piston 41, and allows the flow of brake fluid in the reverse direction. . In an initial state in which the piston 41 is maximum displaced in the x-axis negative direction side, the supply hole 410 is located between the inner peripheral lips of the seal members 431 and 432 and communicates with the supply port 303.

The stroke simulator 5 operates in accordance with the driver's braking operation, and applies a reaction force and a stroke to the brake pedal 100. The stroke simulator 5 includes a piston 51, a first spring unit 52, and a second spring unit 53. The piston 51 has a bottomed cylindrical shape and is accommodated in the second cylinder 31. The piston 51 is movable in the x-axis direction along the inner peripheral surface of the small diameter portion 311. The second cylinder 31 has a positive pressure chamber 501 (main chamber) defined between the piston 51 and the x axis negative direction end of the small diameter portion 311, and the piston 51 and the x axis positive direction end of the large diameter portion 312 In the meantime, a back pressure chamber 502 (sub chamber) is defined. A back pressure liquid path 35 is always open in the back pressure chamber 502.

Seal members

541 and 542 as rod seals are fitted in the

seal grooves

313 and 314, respectively. The

seal members

541 and 542 are ring-shaped packings having a U-shaped cross section. On the outer peripheral side of the piston 51, the seal member 542 on the x-axis positive direction side suppresses the flow of brake fluid from the back pressure chamber 502 side to the positive pressure chamber 501 side, and the seal member 541 on the x-axis negative direction side. Suppresses the flow of brake fluid from the positive pressure chamber 501 side toward the back pressure chamber 502 side. Both chambers 501 and 502 are liquid-tightly separated by

seal members

541 and 542. First and

second spring units

52 and 53 are accommodated in the back pressure chamber 502. The first spring unit 52 includes a first spring 520, a first retainer 521, a second retainer 522, a stopper 523, and a first damper 524. The first spring 520 is a compression coil spring, and both ends thereof are held by the first and

second retainers

521 and 522, respectively. The first spring 520 has a maximum axial length limited by a stopper 523, is in a state of being constantly compressed, and can be compressed and elastically deformed within a predetermined amount in the axial direction. The first damper 524 is an elastic member such as rubber, and is between the stopper 523 and the piston 51 inside the first retainer 521. The second spring unit 53 includes a second spring 530, a third retainer 531, a plug member 532, and a second damper 533. The plug member 532 closes the opening of the second cylinder 31 on the x axis positive direction side. The second spring 530 is a large-diameter compression coil spring having a spring coefficient larger than that of the first spring 520, and both ends are held by the third retainer 531 and the plug member 532. The third retainer 531 holds the second retainer 522. The second spring 530 is in a state where it is always compressed and can be compressed and elastically deformed within a predetermined amount in the axial direction. The second damper 533 is an elastic member such as rubber and is installed on the plug member 532. The first spring unit 52 is located between the second spring unit 53 and the piston 51. The first and

second springs

520 and 530 function as return springs that constantly urge the piston 51 toward the negative x-axis direction. The first damper 524 starts compressive elastic deformation when the first spring 520 is compressed by a predetermined amount or more in the axial direction, and alleviates the impact. When the second spring 530 is compressed by a predetermined amount or more in the axial direction, the second damper 533 starts compressive elastic deformation and alleviates the impact.

The second unit 1B is a hydraulic pressure control device as a brake device. The second unit 1B includes a housing 6, a motor 7a, a pump 7, a plurality of electromagnetic valves 81 and the like, a plurality of hydraulic pressure sensors 92 and the like, and an electronic control unit (control unit; hereinafter referred to as ECU) 90. Have The housing 6 accommodates valve bodies such as the pump 7 and the electromagnetic valve 81 therein. Inside the housing 6, the above-mentioned two systems (P system and S system) in which the brake fluid flows (brake fluid pressure circuit) are formed by a plurality of fluid paths. The plurality of liquid paths are the supply liquid path 11, the suction liquid path 12, the discharge liquid path 13, the pressure regulation liquid path 14, the decompression liquid path 15, the back pressure liquid path 16, and the first simulator liquid path 17. And a second simulator liquid path 18. There are a plurality of ports 67 inside the housing 6, and these ports 67 open to the outer surface of the housing 6. The plurality of ports 67 are continuous with the liquid path 11 and the like inside the housing 6 and connect the liquid path 11 and the like inside the housing 6 with a liquid path (pipe 10M and the like) outside the housing 6. The plurality of ports 67 include a master cylinder port 671 (primary port 671P, secondary port 671S), a wheel cylinder port 672, a suction port 673, and a back pressure port 674. The master cylinder port 671 connects to the supply liquid path 11 inside the housing 6 and connects the housing 6 (second unit 1B) to the master cylinder 4 (hydraulic pressure chamber 40). The other end of the primary pipe 10MP is connected to the primary port 671P. The other end of the secondary pipe 10MS is connected to the secondary port 671S. The suction port 673 connects to the first liquid reservoir chamber 63 inside the housing 6 and connects the housing 6 to the reservoir tank 2 (second chamber 23R). The other end of the suction pipe 10R is connected to the suction port 673. The back pressure port 674 connects to the back pressure liquid path 16 inside the housing 6 and connects the housing 6 to the stroke simulator 5 (back pressure chamber 502). The other end of the back pressure pipe 10X is connected to the back pressure port 674. The wheel cylinder port 672 connects to the supply liquid path 11 inside the housing 6 and connects the housing 6 (second unit 1B) to the wheel cylinder 101. One end of a wheel cylinder pipe 10W is connected to the wheel cylinder port 672.

The motor 7a is a rotary electric motor and includes a rotating shaft for driving the pump 7. The motor 7a may be a motor with a brush, or may be a brushless motor provided with a resolver that detects the rotation angle or the rotation speed of the rotating shaft. The pump 7 is a second hydraulic pressure source that is driven by a motor 7a and can supply hydraulic fluid pressure to the wheel cylinder 101, and is commonly used in the S system and the P system. The electromagnetic valve 81 or the like is an actuator that operates in response to a control signal, and includes a solenoid and a valve body. The valve body strokes in response to energization of the solenoid, and switches between opening and closing the liquid path (connecting and disconnecting the liquid path). The electromagnetic valve 81 or the like generates a control hydraulic pressure by controlling the communication state of the circuit and adjusting the flow state of the brake fluid. The plurality of solenoid valves 81 and the like include a shut-off valve 81, a pressure increasing valve (hereinafter referred to as SOL / V IN) 82, a communication valve 83, a pressure regulating valve 84, and a pressure reducing valve (hereinafter referred to as SOL / V OUT). 85 and a stroke simulator in valve (hereinafter referred to as SS / V IN) 87 and a stroke simulator out valve (hereinafter referred to as SS / V OUT) 88. The shut-off valve 81, the SOL / V IN 82, and the pressure regulating valve 84 are normally open valves that open in a non-energized state. The communication valve 83, the pressure reducing valve 25, SS / V IN87, and SS / V OUT88 are normally closed valves that close in a non-energized state. The shut-off valve 81, the SOL / V IN 82, and the pressure regulating valve 84 are proportional control valves in which the opening degrees of the valves are adjusted according to the current supplied to the solenoid. The communication valve 83, the pressure reducing valve 25, SS / V IN87, and SS / V OUT88 are on / off valves that are controlled to be switched in a binary manner. These valves may be proportional control valves. The hydraulic pressure sensor 92 and the like detect the discharge pressure of the pump 7 and the master cylinder pressure. The plurality of hydraulic pressure sensors 92 and the like include a master cylinder pressure sensor 92, a wheel cylinder pressure sensor 93 (a primary pressure sensor 93P and a secondary pressure sensor 93S), and a discharge pressure sensor 94. The ECU 90 receives detection values of the stroke sensor 91 and the hydraulic pressure sensor 92 and information on the running state from the vehicle side, and based on a built-in program, opens and closes the electromagnetic valve 81 and the rotational speed of the motor 7a (that is, By controlling the discharge amount of the pump 7, the wheel cylinder hydraulic pressure (hydraulic braking force) of each wheel FL to RR is controlled. As a result, the ECU 90 can be used for various brake controls (anti-lock brake control to suppress wheel slip due to braking, boost control to reduce the driver's brake operation force, and vehicle motion control. Brake control, automatic brake control such as preceding vehicle follow-up control, regenerative cooperative brake control, etc.). Vehicle motion control includes vehicle behavior stabilization control such as skidding prevention. In regenerative cooperative brake control, the wheel cylinder hydraulic pressure is controlled so as to achieve the target deceleration (target braking force) in cooperation with the regenerative brake.

Hereinafter, the brake hydraulic circuit of the second unit 1B will be described. The members corresponding to the wheels FL to RR are appropriately distinguished by adding suffixes a to d at the end of the reference numerals. One end side of the supply liquid path 11P is connected to the primary port 671P. The other end of the liquid path 11P branches into a liquid path 11a for the front left wheel and a liquid path 11d for the rear right wheel. Each

fluid passage

11a, 11d is connected to a corresponding wheel cylinder port 672. One end side of the supply liquid path 11S is connected to the secondary port 671S. The other end of the liquid path 11S branches into a liquid path 11b for the front right wheel and a liquid path 11c for the rear left wheel. Each

fluid passage

11b, 11c is connected to a corresponding wheel cylinder port 672. A shut-off valve 81 is provided on the one end side of the liquid path 11. The liquid paths 11a to 11d on the other end side have SOL / VSOLIN82. There is a bypass liquid passage 110 in parallel with each liquid passage 11 bypassing SOL / V IN 82, and a check valve 820 is provided in the liquid passage 110. The valve 820 allows only the flow of brake fluid from the wheel cylinder port 672 side to the master cylinder port 671 side.

The suction liquid path 12 connects the first liquid reservoir chamber 63 and the suction port 623a of the pump 7. The first liquid reservoir chamber 63 is a volume chamber on the suction liquid passage 12, and functions as a reservoir (internal reservoir). One end side of the discharge liquid passage 13 is connected to the discharge port 624a of the pump 7. The other end side of the discharge liquid path 13 branches into a liquid path 13P for the P system and a liquid path 13S for the S system. Each

liquid path

13P, 13S is connected between the shutoff valve 81 and the SOL / V IN 82 in the supply liquid path 11. Each

fluid passage

13P, 13S has a communication valve 83. Each of the

liquid paths

13P and 13S functions as a communication path that connects the supply liquid path 11P of the P system and the supply liquid path 11S of the S system. The pump 7 is connected to each wheel cylinder port 672 via the communication path (discharge

liquid paths

13P, 13S) and the

supply liquid paths

11P, 11S. The pressure adjusting liquid path 14 connects the pump 7 and the communication valve 83 in the discharge liquid path 13 to the first liquid reservoir chamber 63. The liquid passage 14 has a pressure regulating valve 84 as a first pressure reducing valve. The depressurizing liquid path 15 connects the first liquid reservoir chamber 63 between the SOL / V IN 82 and the wheel cylinder port 672 in each of the liquid paths 11a to 11d of the supply liquid path 11. The liquid path 15 has SOL / V OUT85 as a second pressure reducing valve.

一端 One end of the back pressure fluid passage 16 is connected to the back pressure port 674. The other end side of the liquid path 16 branches into a first simulator liquid path 17 and a second simulator liquid path 18. The first simulator liquid path 17 is connected between the shutoff valve 81S and the SOL / V IN 82b, 22c in the supply liquid path 11S. In liquid line 17, there is SS / V 液 IN87. Bypassing SS / V170IN87, there is a bypass fluid passage 170 in parallel with the fluid passage 17, and the fluid passage 170 has a check valve 870. The valve 870 allows only the flow of brake fluid from the back pressure fluid passage 16 side to the supply fluid passage 11S side. The second simulator liquid path 18 is connected to the first liquid reservoir chamber 63. There is SS / V OUT88 in the liquid channel 18. Bypassing SS / V180OUT88, there is a bypass liquid path 180 in parallel with the liquid path 18, and the liquid path 180 has a check valve 880. The valve 880 allows only the flow of the brake fluid from the first liquid reservoir chamber 63 side toward the back pressure fluid path 16 side. Between the shutoff valve 81S and the secondary port 671S in the supply fluid path 11S, a fluid pressure sensor 92 that detects the fluid pressure at this location (the fluid pressure in the positive pressure chamber 501 of the stroke simulator 5 and the master cylinder pressure) is provided. is there. Between the shut-off valve 81 and the SOL / V IN 82 in the supply fluid path 11, there is a fluid pressure sensor 93 that detects the fluid pressure at this location (corresponding to the wheel cylinder fluid pressure). Between the pump 7 and the communication valve 83 in the discharge liquid passage 13, there is a liquid pressure sensor 94 that detects the liquid pressure (pump discharge pressure) at this location.

The

brake chambers

40P and 40S of the master cylinder 4 are supplied with brake fluid from the reservoir tank 2, and generate hydraulic pressure (master cylinder pressure) by the movement of the piston 41. The second unit 1B can supply a master cylinder pressure to each wheel cylinder 101. The master cylinder 4 is connected to the wheel cylinder 101 via the master cylinder pipe 10M, the supply liquid path 11 (of the second unit 1B), and the wheel cylinder pipe 10W, and the wheel cylinder hydraulic pressure can be increased. The brake fluid that has flowed out of the master cylinder 4 due to the driver's braking operation flows into the master cylinder piping 10M and is taken into the supply liquid passage 11 through the master cylinder port 671. The master cylinder 4 can pressurize the wheel cylinders 101 (FL) and 101 (RR) through the P system liquid passage (supply liquid passage 11P) by the master cylinder pressure generated in the primary chamber 40P. At the same time, the master cylinder 4 can pressurize the wheel cylinders 101 (FR) and 101 (RL) via the S system liquid path (supply liquid path 11S) by the master cylinder pressure generated in the secondary chamber 40S. The first unit 1A does not include a negative pressure booster that boosts the driver's brake operation force by using negative pressure generated by a vehicle engine or a negative pressure pump provided separately. The ECU 90 deactivates the pump 7, and controls the shut-off valve 81 in the opening direction, SS / V IN87 in the closing direction, and SS / V OUT88 in the closing direction. In a state where the shut-off valve 81 is controlled in the opening direction, a fluid passage system (supply fluid passage 11 or the like) that connects the hydraulic chamber 40 of the master cylinder 4 and the wheel cylinder 101 is a master that is generated using pedal depression force. A pedal force brake (non-boosting control) that creates wheel cylinder hydraulic pressure using cylinder pressure is realized. The ECU 90 controls the SS / V OUT 88 in the closing direction. As a result, the stroke simulator 5 does not function.

In a state where communication between the master cylinder 4 and the wheel cylinder 101 is cut off, the second unit 1B uses the hydraulic pressure generated by the pump 7 to control the hydraulic pressure of each wheel cylinder 101 independently of the brake operation by the driver. It can be controlled individually. The ECU 90 controls the shut-off valve 81 in the closing direction. In this state, the brake system (the suction fluid passage 12, the discharge fluid passage 13, etc.) connecting the first fluid reservoir 63 and the wheel cylinder 101 creates the wheel cylinder fluid pressure by the fluid pressure generated using the pump 7. It functions as a so-called brake-by-wire system. The pump 7 sucks and discharges the brake fluid in the first liquid reservoir chamber 63. The first fluid reservoir chamber 63 is supplied with brake fluid from the reservoir tank 2 via the pipe 10R. The second unit 1B supplies the brake fluid boosted by the pump 7 to the wheel cylinder 101 via the wheel cylinder pipe 10W. As a result, it is possible to generate a brake fluid pressure (wheel cylinder fluid pressure) and generate a braking torque in a vehicle on which the brake system 1 is mounted. The ECU 90 controls SS / V IN87 in the closing direction and SS / V OUT88 in the opening direction. Thereby, the stroke simulator 5 functions. When the brake fluid flows from the master cylinder 4 into the positive pressure chamber 501 of the stroke simulator 5 according to the driver's brake operation, a pedal stroke occurs and the urging force of the first and

second springs

520 and 530 causes the driver to A brake operation reaction force (pedal reaction force) is generated.

For example, the ECU 90 creates a wheel cylinder hydraulic pressure higher than the master cylinder pressure using the discharge pressure of the pump 7 as a hydraulic pressure source when the driver operates the brake, and generates a hydraulic braking force that is insufficient for the driver's brake operating force. The generated boost control is executed. Specifically, based on the detected pedal stroke, a desired boost ratio, that is, the ideal relationship between the pedal stroke and the driver's required brake fluid pressure (vehicle deceleration requested by the driver) is achieved. The target wheel cylinder hydraulic pressure is calculated. The pump 7 is operated to control the shut-off valve 81 in the closing direction and the communication valve 83 in the opening direction. The target wheel cylinder hydraulic pressure is realized by adjusting the amount of brake fluid supplied from the pump 7 to the wheel cylinder 101 by controlling the pressure regulating valve 84 while operating the pump 7 at a predetermined rotational speed. That is, the brake system 1 exhibits a boost function that assists the brake operation force by operating the pump 7 of the second unit 1B instead of the engine negative pressure booster. Further, the ECU 90 calculates the target wheel cylinder hydraulic pressure in relation to the regenerative braking force during regenerative cooperative brake control. For example, the target wheel cylinder in which the sum of the regenerative braking force input from the control unit of the regenerative braking device of the vehicle and the hydraulic braking force corresponding to the target wheel cylinder hydraulic pressure satisfies the vehicle deceleration required by the driver. Calculate fluid pressure. At the time of motion control, for example, the target wheel cylinder hydraulic pressure of each wheel FL to RR is calculated so as to realize a desired vehicle motion state based on the detected vehicle motion state amount (lateral acceleration or the like).

¡SS / V OUT88, SS / VIN87 and check valve 870 adjust the flow of brake fluid flowing from the back pressure port 674 into the housing 6 through the back pressure pipe 10X. These valves 88 and the like allow or prohibit the brake fluid flowing into the housing 6 from the back pressure port 674 from flowing toward any low pressure part (the first liquid reservoir chamber 63 or the wheel cylinder 101), Allow or prohibit the flow of brake fluid from the master cylinder 4 into the stroke simulator 5 (positive pressure chamber 501). Thereby, the operation of the stroke simulator 5 is adjusted. Further, these valves 88 and the like provide a supply destination (outflow destination) of the brake fluid flowing into the housing 6 (back pressure fluid passage 16) from the back pressure port 674 between the first fluid reservoir chamber 63 and the wheel cylinder 101. It functions as a switching unit that switches at. For example, when the ECU 90 determines that the brake operation state is a predetermined sudden brake operation state, the ECU 90 operates the pump 7, controls the shut-off valve 81 in the closing direction, and sets SS / V IN87 in the opening direction, and the SS / V Controls OUT88 in the closing direction. Thus, the second pedal force brake that creates the wheel cylinder hydraulic pressure using the brake fluid flowing out from the back pressure chamber 502 of the stroke simulator 5 until the pump 7 can generate a sufficiently high wheel cylinder pressure. Is realized. Thereby, the pressurization responsiveness of wheel cylinder hydraulic pressure is securable. When the pump 7 can generate a sufficiently high wheel cylinder pressure, it switches to boost control or the like.

Next, the housing 6 of the second unit 1B will be described with reference to FIG. In FIG. 2, a three-dimensional orthogonal coordinate system having an X axis, a Y axis, and a Z axis is provided for convenience of explanation. When the second unit 1B is mounted on the vehicle, the Z-axis direction is the vertical direction, and the Z-axis positive direction side is the vertical direction upper side. The X-axis direction is the vehicle front-rear direction, and the X-axis positive direction side is the vehicle front side. The Y-axis direction is the lateral direction of the vehicle. In actual use, the arrangement of the housing 6 is not restricted at all, and the housing 6 can be arranged at an arbitrary position and orientation in accordance with the vehicle layout and the like. In FIG. 2, the housing 6 is viewed from the X axis positive direction side, the Y axis negative direction side, and the Z axis positive direction side. The housing 6 is a substantially rectangular parallelepiped block formed of an aluminum alloy. The outer surface of the housing 6 has a front surface 601, a back surface, a lower surface 603, an upper surface 604, a left side surface 605, and a right side surface 606. The front surface 601 and the back surface are planes having a relatively large area and are orthogonal to the Y axis. The lower surface 603 and the upper surface 604 are planes connected to the front surface 601 and the back surface, and are orthogonal to the Z axis. The left side surface 605 and the right side surface 606 are planes connected to the front surface 601, the back surface, the lower surface 603, and the upper surface 604, and are orthogonal to the X axis.

There is a recess 60 at the corner of the housing 6 on the front 601 side and the upper surface 604 side. That is, the apex formed by the front 601, the upper surface 604 and the right side 606, and the apex formed by the front 601, the upper surface 604 and the left side 605 are cut out shapes, respectively, Two

recesses

60a and 60b are provided. The first recess 60a is opened (opened) to the front surface 601, the upper surface 604, and the left side surface 605. The second recess 60b is opened to the front surface 601, the upper surface 604, and the right side surface 606. The housing 6 includes a cam accommodating hole 61, a plurality (five) of cylinder accommodating holes 62A to 62E, a first liquid reservoir chamber 63, a second liquid reservoir chamber 64, a plurality of fixing holes 65, and a plurality of valves. It has an accommodation hole, a plurality of sensor accommodation holes, a power supply hole 66, a plurality of ports 67, a plurality of liquid passages 11 and the like. These holes and ports are formed by a drill or the like. The cam accommodation hole 61 has a bottomed cylindrical shape having an axis O extending in the Y-axis direction, and opens in the approximate center of the front surface 601.

The cylinder accommodation hole 62 has a stepped cylindrical shape having an axis Q extending in the radial direction of the cam accommodation hole 61 (radial direction centered on the axis O). The plurality of holes 62 are provided radially about the axis O. The holes 62A to 62E are evenly (equally spaced) in the direction around the axis O. The angle formed by the axis Q of the holes 62 adjacent in the direction around the axis O is 72 °. The holes 62A to 62E are in a single row along the Y-axis direction and are arranged on the Y-axis negative direction side of the housing 6. The axial centers Q of the holes 62A to 62E are in the same plane orthogonal to the axial center O. FIG. 3 shows a cross section of the second unit 1B cut along this plane. The hole 62 has a minimum diameter portion 621, a small diameter portion 622, a medium diameter portion 623, a large diameter portion 624, and a maximum diameter portion 625 in order from the side closer to the cam housing hole 61 to the side farther from the cam accommodation hole 61. Each of these parts is cylindrical and has the same axis Q. Between the medium-diameter portion 623 and the large-diameter portion 624, there is a flat portion 626 that extends in a direction (axial direction) orthogonal to the axis Q of the hole 62. In the medium diameter portion 623, a portion 623a closer to the small diameter portion 622 has a slightly larger diameter than the other portions. The portions 623a of the holes 62A to 62E are connected to each other by the suction liquid passage 12 and to the first liquid reservoir chamber 63, and function as suction ports for the pump portions 7A to 7E. In the large diameter portion 624 of each hole 62A to 62E, the portion 624a on the side close to the medium diameter portion 623 is connected to each other by the discharge liquid passage 13, and functions as a discharge port of the pump portions 7A to 7E.

The holes 62A to 62E are arranged inside the housing 6 as follows. The hole 62A extends from the lower surface 603 to the Z axis positive direction side. The hole 62B extends from the portion of the left side surface 605 located on the lower side in the Z-axis negative direction with respect to the axis O to the X-axis positive direction side and the Z-axis positive direction side. The hole 62C extends from the first recess 60a to the X axis positive direction side and the Z axis negative direction side. The hole 62D extends from the second recess 60b to the X-axis negative direction side and the Z-axis negative direction side. The hole 62E extends from the portion of the right side surface 606 located on the lower side in the Z-axis negative direction with respect to the axis O to the X-axis negative direction side and the Z-axis positive direction side. The hole 62A is at the same X-axis position as the axis O on the Z-axis negative direction side with respect to the axis O, and the

holes

62B and 62E are arranged on both sides in the X-axis direction with the axis O (hole 62A) in between. The The holes 62C and 62D are arranged on both sides in the X-axis direction with the axis O in between on the Z-axis positive direction side with respect to the axis O. The minimum diameter portion 621 of each of the holes 62A to 62E opens on the inner peripheral surface of the cam accommodating hole 61. The maximum diameter portion 625 of the hole 62A opens to the approximate center of the lower surface 603 in the X-axis direction and the negative Y-axis side. The maximum diameter portion 625 of the hole 62B opens on the Y axis negative direction side and the Z axis negative direction side of the left side surface 605. The maximum diameter portion 625 of the hole 62E opens on the Y axis negative direction side and the Z axis negative direction side of the right side surface 606. The maximum diameter portions 625 of the

holes

62C and 62D open to the first and

second recesses

60a and 60b, respectively.

The first liquid reservoir chamber 63 has a bottomed cylindrical shape whose axial center extends in the Z-axis direction, and opens toward the approximate center in the X-axis direction on the upper surface 604 and closer to the negative Y-axis direction. The second liquid reservoir chamber 64 has a bottomed cylindrical shape whose axis extends in the Z-axis direction, and opens toward the X-axis negative direction side and the Y-axis negative direction side of the lower surface 603. The cam housing hole 61 and the second liquid reservoir chamber 64 are connected by a drain liquid passage 19. The plurality of valve accommodation holes and sensor accommodation holes extend in the Y-axis direction and open on the back surface. These holes are in a single row along the Y-axis direction, and are disposed on the Y-axis positive direction side of the housing 6. When viewed from the Y-axis direction, the cylinder accommodation hole 62 and the valve accommodation hole and the like overlap at least partially. The valve portion of the electromagnetic valve is fitted in each valve accommodation hole, and the valve body is accommodated. Each sensor accommodation hole accommodates a pressure sensitive part such as the hydraulic pressure sensor 92. The power supply hole 66 is disposed in a region between adjacent

cylinder accommodation holes

62C and 62D, and penetrates the housing 6 (between the front surface 601 and the back surface) in the Y-axis direction. The suction port 673 is an opening of the first liquid reservoir chamber 63 on the upper surface 604. The master cylinder port 671 has a bottomed cylindrical shape whose axial center extends in the Y-axis direction, and opens at a portion of the front 601 on the Z-axis positive direction side and sandwiched between the

recesses

60a and 60b. The wheel cylinder port 672 has a bottomed cylindrical shape whose axis extends in the Z-axis direction, and opens on the Y axis positive direction side of the upper surface 604. Ports 672a to 872d are arranged in a line in the X-axis direction. The back pressure port 674 has a bottomed cylindrical shape whose axial center extends in the X-axis direction, and opens to the Z-axis negative direction side of the right side surface 606. The plurality of liquid passages 11 and the like connect the port 67, the

liquid reservoir chambers

63 and 64, the cylinder accommodation hole 62, the valve accommodation hole, and the hydraulic pressure sensor accommodation hole.

The plurality of fixing holes 65 include a bolt hole 651 for fixing the motor, a bolt hole for fixing the ECU, a bolt hole 652 for fixing the housing, and a pin hole. A motor 7a is disposed on the front surface 601 of the housing 6, and the motor housing is attached to the hole 651 with a bolt. The housing 6 (accommodating the pump 7) and the motor 7a are integrated as a second unit 1B, and the second unit 1B functions as a pump device. A conductive member (power connector) is connected to the rotor of the motor 7a via a brush. The conductive member is accommodated in the power supply hole 66. An ECU 90 is disposed on the back surface of the housing 6. That is, the ECU 90 is provided integrally with the housing 6, and the ECU 90 and the housing 6 are integrated as the second unit 1B. The housing 6 is sandwiched between the motor 7a and the ECU 90. That is, the motor 7a, the housing 6, and the ECU 90 are arranged in this order along the axial direction of the motor 7a. The ECU 90 has a control board and a housing (case). The control board is accommodated in the case and arranged in parallel with the back surface. The case is attached to the back surface of the housing 6. From the back, a solenoid terminal such as the electromagnetic valve 81, a terminal such as the hydraulic pressure sensor 92, and a conductive member from the motor 7a protrude. The terminals and conductive members extend to the Y axis positive direction side and are directly connected to the control board. Power is supplied to the control board from an external power source (battery). The conductive member functions as a connecting portion that electrically connects the control board and the motor 7a (rotor), and power is supplied from the control board to the motor 7a (rotor) via the conductive member. Various sensors for detecting the motion state of the vehicle, for example, an acceleration sensor for detecting the acceleration of the vehicle and an angular velocity sensor for detecting the angular velocity (yaw rate) of the vehicle may be mounted on the control board. A pedestal (mounting member) is fixed to the vehicle body side. Bolts and pins are fixed in the holes 652 of the housing 6. The bolts and the like fix the housing 6 to the base via an insulator (an elastic member for suppressing vibration).

Hereinafter, the details of the pump 7 will be described with reference to FIGS. In FIG. 5, the cross section of the pump portion 7A is viewed from the X-axis negative direction side, the Y-axis negative direction side, and the Z-axis negative direction side. In FIG. 6, the cylinder 71, the piston 75, the valve case 76, the first ball 771, the third spring 783, and the third seal member 793 that are disassembled and arranged coaxially are viewed obliquely. In FIG. 7, the piston 75, the valve case 76, the first ball 771, the first spring 781, and the third seal member 793 disassembled and arranged coaxially are viewed obliquely. As shown in FIG. 3, the cam housing hole 61 (inside the housing 6) accommodates a rotation drive shaft 700 that is a rotation shaft and a drive shaft of the pump 7, and a cam mechanism 70. The rotational drive shaft 700 is a drive shaft of the pump 7. The rotational drive shaft 700 is connected and fixed to the rotational shaft of the motor 7a, and is rotationally driven by the motor 7a. The axis (axis) of the rotation drive shaft 700 (the rotation axis of the motor 7a) substantially coincides with the axis O of the cam accommodation hole 61 (within the tolerance of each member, the same applies hereinafter). The rotation drive shaft 700 rotates around the axis O together with the rotation shaft of the motor 7a. The cam mechanism 70 is provided on the outer periphery of the rotary drive shaft 700, and includes a cam (eccentric part) 70a and a drive unit 70b. The cam mechanism 70 is a mechanism for driving the piston 75 using the cam 70a. The cam 70a is a cylindrical eccentric cam, and has an axis P that is eccentric with respect to the axis O of the rotary drive shaft 700. The axis P extends substantially parallel to the axis O. The cam 70a oscillates (the shaft center P rotates relative to the shaft center O) while rotating around the shaft center O integrally with the rotation drive shaft 700. The drive unit 70b is cylindrical and is disposed on the outer peripheral side of the cam 70a. The axis of the drive unit 70b coincides with the axis P. The drive unit 70b includes a plurality of rolling elements 701, a holder 702, and a drive member 703 as one assembly. This assembly has the same configuration as a so-called shell-shaped needle roller bearing. The rolling element 701 is a needle roller and extends in the axial direction of the rotation drive shaft 700. The cage 702 has a cylindrical shape, and holds the rolling elements 701 in a rotatable manner independently of each other at substantially constant intervals in the circumferential direction. The drive member 703 has the same configuration as the outer ring of the rolling bearing, and is disposed on the outer peripheral side of the cage 702. The drive member 703 can rotate around the axis P with respect to the cam 70a. The plurality of rolling elements 701 are disposed between the outer peripheral surface of the cam 70a and the inner peripheral surface of the drive member 703.

The pump 7 is a fixed cylinder type radial plunger pump, and includes a housing 6, a rotary drive shaft 700, a cam mechanism 70, and a plurality (five) of pump units 7A to 7E. When the configurations of the pump units 7A to 7E are distinguished from each other, suffixes A to E are added to the reference numerals. The pump units 7A to 7E are plunger pumps (piston pumps) as reciprocating pumps, and operate by rotation of the rotary drive shaft 700. As the piston (plunger) 75 reciprocates, the brake fluid is sucked and discharged as hydraulic fluid. The pump portions 7A to 7E are arranged around the cam mechanism 70 and are received in the cylinder receiving holes 62, respectively. The axial center of the piston 75 substantially coincides with the axial center Q of the cylinder accommodation hole 62 (within a width that allows smooth operation of the piston 75), and extends in the radial direction of the rotary drive shaft 700. In other words, the pistons 75 are provided in the number corresponding to the number of the cylinder accommodation holes 62 (five), and extend in the radial direction with respect to the axis O. The pistons 75A to 75E are arranged evenly (at equal intervals) in the direction around the rotational drive shaft 700 (hereinafter simply referred to as the circumferential direction), that is, in the rotational direction of the rotational drive shaft 700. The axes Q of the pistons 75A to 75E are in the same plane. The pistons 75A to 75E are driven by the same rotation drive shaft 700 and the same cam mechanism 70. Each pump portion 7A to 7E includes a cylinder 71, a plug member 72a, a stopper 72b, a filter member 73, a guide 74, a piston 75, a valve case 76, a first ball 771, and a second ball 772. The first spring 781, the second spring 782, the third spring 783, the first seal member 791, the second seal member 792, and the third seal member 793 are provided. Hereinafter, the pump unit 7A will be described as an example with reference to FIGS. The other pump units 7B to 7E have the same configuration.

The cylinder (cylinder sleeve) 71 has a bottomed cylindrical shape, and has a cylindrical inner periphery 717 and a bottom portion 710. The bottom 710 has a first hole 711 and a second hole 712. Both

holes

711 and 712 extend in the axial direction on the axial center of the cylinder 71. The first hole 711 is a bottomed cylindrical recess and opens on the surface of one side of the bottom 710 in the axial direction (Z-axis positive direction side, the same applies hereinafter). The second hole 712 has a smaller diameter than the first hole 711. The second hole 712 passes through the bottom portion 710 and opens to the bottom surface of the first hole 711 and the other surface in the axial direction of the bottom portion 710 (the Z-axis negative direction side, the same applies hereinafter). A surface 716 on the other side in the axial direction of the bottom portion 710 has a planar shape extending in a direction perpendicular to the axis of the cylinder 71. The periphery of the opening of the second hole 712 in the surface 716 is a conical surface. The outer peripheral side of the cylinder 71 has a main body portion 71a, a first end portion 71b, and a second end portion 71c. The main body 71a has a cylindrical shape, and its diameter is substantially equal to the diameter of the middle diameter portion 623 of the cylinder accommodation hole 62. The first end portion 71b has a cylindrical shape coaxial with the main body portion 71a, is on one side in the axial direction with respect to the main body portion 71a, and has a smaller diameter than the main body portion 71a. Between the main body portion 71a and the first end portion 71b, there is a tapered portion 71d whose diameter gradually decreases from the main body portion 71a side toward the first end portion 71b side. The second end 71c is on the other side in the axial direction with respect to the main body 71a, has a cylindrical shape coaxial with the main body 71a, and has a larger diameter than the main body 71a. The second end portion 71c has a first flange portion 71c1 and a second flange portion 71c2. The first flange portion 71c1 protrudes radially outward from the end on the one axial side of the second end portion 71c. A portion connected to the first flange portion 71c1 in the main body portion 71a has a groove 713 extending in the circumferential direction. One axial direction side of the first flange portion 71c1 has a flat surface portion 714 that extends in the direction perpendicular to the axial direction of the cylinder 71. The other axial side of the first flange portion 71c1 has a tapered portion 715 that gradually decreases in diameter toward the other axial side. The diameter of the first flange portion 71c1 (plane portion 714) is larger than the diameter of the medium diameter portion 623 of the cylinder accommodation hole 62 and smaller than the diameter of the large diameter portion 624. The second flange portion 71c2 protrudes radially outward from the other axial end of the second end portion 71c and has a smaller diameter than the first flange portion 71c1. The cylinder 71 is accommodated in the cylinder accommodation hole 62 and is fixed to the hole 62 by, for example, press fitting. The main body portion 71a is fixed to the middle diameter portion 623 of the hole 62. The axis of the cylinder 71 substantially coincides with the axis Q of the cylinder accommodation hole 62. When the flat surface portion 714 of the first flange portion 71c1 contacts the flat surface portion 626 of the hole 62, the axial position of the cylinder 71 with respect to the hole 62 is restricted. The first end portion 71b is disposed in the middle diameter portion 623 (suction port 623a) of the hole 62, and the second end portion 71c (and bottom portion 710) is disposed in the large diameter portion 624 (discharge port 624a) of the hole 62.

The plug member 72a has a columnar main body 72a1 and a columnar projection 72a2 coaxially. The diameter of the main body portion 72a1 is slightly smaller than the diameter of the large diameter portion 624 of the cylinder accommodation hole 62. The outer periphery of the main body 72a1 has a groove 720 extending in the circumferential direction. One side of the main body portion 72a1 in the axial direction has a first hole 721, a second hole 722, and a plurality of grooves 723. Both

holes

721 and 722 extend in the axial direction on the axial center of the main body 72a1. The first hole 721 is a bottomed cylindrical recess. The diameter of the first hole 721 is slightly larger than the diameter of the second flange portion 71c2 of the cylinder 71. The bottom surface 724 of the first hole 721 has a planar shape that extends in the direction perpendicular to the axis of the main body 72a1. The second hole 722 is a bottomed cylindrical recess that opens to the bottom surface 724. The diameter of the second hole 722 is smaller than the diameter of the first hole 721 and larger than the diameter of the second hole 712 of the cylinder 71. The groove 723 is provided in the bottom surface 724 to a predetermined depth, extends in the radial direction from the second hole 722, and opens to the outer periphery of the main body 72a1. The convex portion 72a2 protrudes from the surface on the other side in the axial direction of the main body portion 72a1. The plug member 72 a is accommodated in the large diameter portion 624 of the cylinder accommodation hole 62 and closes the opening of the cylinder accommodation hole 62 on the outer peripheral surface of the housing 6. The axial center of the plug member 72a substantially coincides with the axial center Q of the cylinder accommodation hole 62 and the cylinder 71. One side of the plug member 72a in the axial direction is installed at the bottom 710 of the cylinder 71. The second flange portion 71c2 of the cylinder 71 is accommodated in the first hole 721 of the plug member 72a, and the surface 716 of the bottom portion 710 contacts the bottom surface 724 of the first hole 721. A passage is formed between the groove 723 and the surface 716. The second hole 712 of the cylinder 71 is connected to the second hole 722 of the plug member 72a.

The stopper 72b has an annular shape. The outer diameter of the stopper 72b is substantially the same as the diameter of the maximum diameter portion 625 of the cylinder accommodation hole 62. One end of the stopper 72b in the axial direction has a bottomed cylindrical recess 725. The bottom surface 726 of the recess 725 has a planar shape extending in the direction perpendicular to the axis of the stopper 72b. The diameter of the recess 725 is slightly larger than the diameter of the main body 72a1 of the plug member 72a. The stopper 72b has a first hole 727 and a second hole 728. Both

holes

727 and 728 penetrate the stopper 72b in the axial direction and open on the surface 726. The first hole 727 extends on the axis of the stopper 72b, and a plurality of second holes 728 are arranged in the circumferential direction so as to surround the first hole 727. The diameter of the first hole 727 is slightly larger than the diameter of the convex portion 72a2 of the plug member 72a. The stopper 72b is accommodated in the maximum diameter portion 625 of the cylinder accommodation hole 62. The outer periphery of the stopper 72b is fixed to the maximum diameter portion 625. The convex part 72a2 of the plug member 72a is accommodated in the first hole 727, and the other axial side of the main body part 72a1 of the plug member 72a is accommodated in the concave part 725. The axial position of the plug member 72a with respect to the hole 62 is regulated by the bottom surface 726 of the recess 725 coming into contact with the surface on the other axial side of the main body 72a1.

The filter member 73 is substantially cylindrical. The inner peripheral side of the filter member 73 has a large diameter portion 73a1, a small diameter portion 73a2, a first taper portion 73a3, and a second taper portion 73a4. The large-diameter portion 73a1 has a bottomed cylindrical shape, and opens on the end surface on the other axial side of the filter member 73. The diameter of the large diameter portion 73a1 is substantially the same as the diameter of the first end portion 71b of the cylinder 71. The small diameter portion 73a2 is on one side of the filter member 73 in the axial direction. The small-diameter portion 73a2 has a cylindrical shape that is coaxial with the large-diameter portion 73a1, and opens on the end surface on one axial side of the filter member 73. The small diameter portion 73a2 has a smaller diameter than the large diameter portion 73a1. The first taper portion 73a3 opens at the bottom of the large diameter portion 73a1, and the diameter gradually decreases from the large diameter portion 73a1 side toward the small diameter portion 73a2. The second taper portion 73a4 is between the first taper portion 73a3 and the small diameter portion 73a2, and gradually (from the first taper portion 73a3 side toward the small diameter portion 73a2 side (slower than the first taper portion 73a3) The diameter becomes smaller (with a gradient). The outer peripheral side of the filter member 73 has a large diameter portion 73b1 and a small diameter portion 73b2. The large diameter portion 73b1 is cylindrical and is on the other side in the axial direction of the filter member 73. The diameter of the large diameter portion 73b1 is smaller than the diameter of the medium diameter portion 623 of the cylinder accommodation hole 62 and larger than the diameter of the small diameter portion 622. The small diameter portion 73b2 is on one side of the filter member 73 in the axial direction. The small diameter portion 73b2 has a cylindrical shape coaxial with the large diameter portion 73b1, and has a smaller diameter than the large diameter portion 73b1. The diameter of the small diameter portion 73b2 is slightly smaller than the diameter of the small diameter portion 622 of the cylinder accommodation hole 62. A plurality of holes penetrates the filter member 73 in the radial direction. These holes open to the first tapered portion 73a3 on the inner peripheral side of the filter member 73, and open to the large diameter portion 73b1 on the outer peripheral side of the filter member 73. A filter covers each hole. The filter member 73 is fixed to the first end 71b of the cylinder 71. The first end 71b is fitted into the large diameter portion 73a1 on the inner peripheral side of the filter member 73. The axis of the filter member 73 substantially coincides with the axis of the cylinder 71. The large-diameter portion 73b1 on the outer peripheral side of the filter member 73 is accommodated on one axial side of the medium-diameter portion 623 of the cylinder accommodation hole 62, and a part of the small-diameter portion 73b2 is the other axial side of the small-diameter portion 622 of the cylinder accommodation hole 62 Is housed in. On the outer peripheral side of the filter member 73, there is a gap between the large diameter portion 73b1 (where the hole is opened) and the medium diameter portion 623 (suction port 623a) of the cylinder accommodation hole 62.

The guide 74 has an annular shape, and has a substantially rectangular cross section cut by a plane passing through its axis. The outer diameter of the guide 74 is substantially equal to the diameter of the small diameter portion 622 of the cylinder accommodation hole 62. The guide 74 is accommodated on one side of the small diameter portion 622 in the axial direction. The outer periphery of the guide 74 is fixed to the small diameter portion 622 by press fitting or the like. The axis of the guide 74 (inner and outer periphery) substantially coincides with the axis Q of the cylinder accommodation hole 62.

The piston 75 has a columnar shape and has a main body portion 75a, an end portion 75b, and a flange portion 75c. The outer periphery of the main body 75a is cylindrical. The outer diameter of the main body 75a is slightly smaller than the diameter of the small diameter portion 73a2 on the inner peripheral side of the filter member 73 and slightly smaller than the inner diameter of the guide 74. An end surface (hereinafter referred to as a piston end surface) 750 in the axial direction of the main body 75a is a flat surface extending in a direction orthogonal to the axial center of the piston 75, and has a circular shape centering on this axial center. The flange portion 75c protrudes radially outward from the other axial side of the main body portion 75a. The outer periphery of the flange portion 75c has a cylindrical shape that is coaxial with the outer periphery of the main body portion 75a. The outer diameter of the flange portion 75c is slightly smaller than the diameter (inner diameter) of the inner periphery 717 of the cylinder 71. The surface 754 on the other axial side of the flange portion 75c is an annular shape centering on the axial center of the piston 75, and has a planar shape extending in the direction perpendicular to the axis. The end portion 75b is at the tip of the main body portion 75a1 on the other side in the axial direction from the flange portion 75c, and the outer periphery thereof is cylindrical. The outer diameter of the end portion 75b is smaller than the outer diameter of the main body portion 75a1. On the outer periphery of the piston 75, there is a tapered portion 75d between the main body portion 75a1 and the end portion 75b. The diameter of the tapered portion 75d gradually decreases from the main body portion 75a1 side toward the end portion 75b side. The piston 75 has a first hole 751 and a second hole 752 therein. The first hole 751 penetrates a portion of the main body 75a adjacent to one side in the axial direction with respect to the flange 75c in the radial direction of the piston 75. The first hole 751 has a cylindrical shape, and its axis crosses the axis of the piston 75. The second hole 752 has a cylindrical shape extending in the axial direction on the axial center of the piston 75, and one end of the second hole 752 is connected to the central part in the axial direction of the first hole 751. The other end of the second hole 752 opens in the end surface 753 on the other axial side of the piston 75. The periphery of the opening of the second hole 752 in the surface 753 is a conical surface.

The valve case 76 has a bottomed cylindrical shape made of a thin plate, and includes a bottom portion 76a, a side wall portion 76b, and a flange portion 76c. The bottom 76a has a disk shape, and the first hole 761 passes through the center of the bottom 76a. The side wall part 76b is cylindrical, has a small diameter part 76b1 on the side close to the bottom part 76a, and has a large diameter part 76b2 on the side far from the bottom part. The inner diameter of the large diameter portion 76b2 is smaller than the outer diameter of the main body portion 75a of the piston 75 and slightly larger than the outer diameter of the end portion 75b of the piston 75. The second hole 762 passes through the side wall portion 76b. A plurality (three) of the second holes 762 are provided in the circumferential direction of the valve case 76 and extend in the axial direction of the valve case 76. The circumferential dimension (width) of the second hole 762 is larger in the large diameter portion 76b2 than in the small diameter portion 76b1. The flange portion 76c extends radially outward from the opening end of the side wall portion 76b (large diameter portion 76b2). The flange portion 76c has a planar shape extending in the direction perpendicular to the side wall portion 76b, and has an annular shape centered on the axis of the side wall portion 76b. The outer diameter of the flange portion 76c is slightly smaller than the inner diameter of the cylinder 71. A third hole 763 passes through the flange portion 76c. The third hole 763 is plural (three) in the circumferential direction of the valve case 76, extends in the radial direction of the valve case 76, and opens to the inner and outer circumferences of the flange portion 76c. The third hole 763 is continuous with the second hole 762. In other words, the valve case 76 is cut at three locations in the circumferential direction by the

holes

762 and 763 and connected to one at the bottom 76a. The valve case 76 is installed at the end 75b of the piston 75. The outer periphery of the end portion 75b is fitted to the inner periphery on the opening side of the side wall portion 76b (large diameter portion 76b2).

The diameter of the first ball 771 is larger than the diameter of the second hole 752 of the piston 75 and smaller than the inner diameter of the valve case 76 (large diameter portion 76b2). The first ball 771 is on the inner peripheral side of the valve case 76 and between the bottom 76a and the end 75b of the piston 75. The first spring 781 is a compression coil spring, and the inner diameter thereof is smaller than the diameter of the first ball 771. The first spring 781 is in the compressed state between the bottom 76a and the first ball 771 on the inner peripheral side of the valve case 76. One end of the first spring 781 is in contact with the bottom 76a (around the opening of the first hole 761), and the other end of the first spring 781 is in contact with the first ball 771 (the outer surface thereof). The first ball 771 and the first spring 781 are elements constituting the suction valve 77a. The first ball 771 functions as a valve body, and the first spring 781 functions as a return spring. The periphery of the opening of the second hole 752 in the end surface 753 of the piston 75 functions as a valve seat. When the first ball 771 is seated on the valve seat, the second hole 752 is closed. The first spring 781 always urges the first ball 771 toward the valve seat with respect to the valve case 76 (piston 75).

The diameter of the second ball 772 is larger than the diameter of the second hole 712 of the bottom portion 710 of the cylinder 71 and smaller than the diameter of the second hole 722 of the plug member 72a. The second ball 772 is on the inner peripheral side of the second hole 722 and between the plug member 72a and the bottom portion 710. The second spring 782 is a compression coil spring, and the inner diameter thereof is smaller than the diameter of the second ball 772. The second spring 782 is in a state of being compressed between the bottom of the hole and the second ball 772 in the hole of the plug member 72a. The second ball 772 and the second spring 782 are elements constituting the discharge valve 77b. The second ball 772 functions as a valve body, and the second spring 782 functions as a return spring. The periphery of the opening of the second hole 712 in the surface 716 of the cylinder 71 functions as a valve seat. The second hole 712 is closed when the second ball 772 is seated on the valve seat. The second spring 782 always urges the second ball 772 toward the valve seat with respect to the plug member 72a.

The third spring 783 is a compression coil spring, and the inner diameter thereof is slightly larger than the outer diameter of the side wall portion 76b (large diameter portion 76b2) of the valve case 76 and smaller than the outer diameter of the flange portion 76c. The third spring 783 has a larger wire diameter and spring constant than the first spring 781. The outer diameter of the third spring 783 is smaller than the inner diameter of the cylinder 71. The third spring 783 is on the inner peripheral side of the cylinder 71 and is compressed between the bottom 710 and the piston 75. One end of the third spring 783 is in contact with the bottom portion 310 (around the opening of the first hole 711), and the other end of the third spring 783 is in contact with the flange portion 76c of the valve case 76. The third spring 783 always biases the valve case 76 (piston 75) toward the cam housing hole 61 with respect to the cylinder 71 (cylinder housing hole 62).

The first seal member 791 is a fixing (stationary) seal, for example, a rubber gasket. The first seal member 791 has an annular shape, and is a D-ring having a substantially D-shaped cross section cut along a plane passing through its axis. The first seal member 791 is accommodated in the groove 720 of the plug member 72a. The second seal member 792 is a contact-type reciprocating seal, for example, a squeeze packing. The second seal member 792 has an annular shape, and has a cross-sectional shape cut along a plane passing through the axial center of the second seal member 792 having an X shape or a rectangular shape (substantially square) with four corners bulging outward. The second seal member 792 is located between the guide 74 and the filter member 73 in the cylinder accommodation hole 62 (small diameter portion 622).

The third seal member 793 is a contact-type reciprocating seal, and is an elastic member formed from a non-metallic material such as resin. The resin is, for example, a polyamide system. At least a part of the material of the third seal member 793 is, for example, polytetrafluoroethylene PTFE. Details of the third seal member 793 will be described with reference to FIGS. FIG. 8 shows a cross section of the piston 75 assembled with the third seal member 793 and the cylinder 71 that accommodates the piston 75 in a plane perpendicular to the axis Q so as to pass through the third seal member 793. . FIG. 9 shows a cross section of the piston 75, to which the third seal member 793 is assembled, cut so as to pass through the third seal member 793 in a plane orthogonal to the axial center thereof. The third seal member 793 has an annular shape, and has a rectangular (square) cross-sectional shape cut along a plane passing through the axis. Each vertex (corner) of the cross section has a curve (R). The cross section may be circular, for example. The third seal member 793 has an end surface 79a on one axial side, an end surface 79b on the other axial side, an inner periphery (surface) 79c, and an outer periphery (surface) 79d. The

surfaces

79a and 79b have a planar shape extending in the direction perpendicular to the axis of the third seal member 793. The inner periphery 79c is polygonal when viewed from the axial direction of the third seal member 793. Specifically, it is a regular hexagon having six sides. In other words, the inner circumference 79 c is a rectangular rectangular (rectangular) side surface 79 c 1 having a regular hexagonal bottom surface, and each side surface 79 c 1 extends in the axial direction of the third seal member 793. Each vertex of the regular hexagon, in other words, each boundary line (connection part) 79c2 of the side surface 79c1 adjacent in the circumferential direction has a curve (R). The (shortest) distance from the axis of the third seal member 793 to each side (side surface) 79c1 is slightly shorter than the distance from the axis of the piston 75 to the outer periphery of the main body 75a1 (radius of the main body 75a1). . The (shortest) distance from the axial center of the third seal member 793 to each vertex (boundary line) 79c2 is longer than the radius of the main body 75a1. The axial dimension of the inner periphery 79c is slightly larger than the axial dimension of the main body 75a1. The outer periphery 79d is cylindrical, and its diameter is substantially the same as or slightly larger than the inner diameter of the cylinder 71. The third seal member 793 is installed between the flange portion 76c of the valve case 76 and the flange portion 75c of the piston 75 so as to surround the main body portion 75a1. The inner periphery 79c faces the outer periphery of the main body portion 75a1. The axis of the third seal member 793 substantially coincides with the axis of the piston 75.

Next, the function and effect will be described. One side in the axial direction of the piston 75 from the first hole 751 is on the inner peripheral side of the small diameter portion 73a2, the second seal member 792, and the guide 74 of the filter member 73, and is guided and supported by these. One end of the piston 75 in the axial direction (piston end surface 750) projects into the cam housing hole 61. The piston end surface 750 comes into contact with the outer peripheral surface of the drive member 703 of the cam mechanism 70 by the force with which the third spring 783 biases the valve case 76 (piston 75). The other axial side of the piston 75 is on the inner peripheral side of the cylinder 71, and the flange portion 75 c is guided and supported by the inner periphery 717 of the cylinder 71. Inside the cylinder housing hole 62, the inner periphery of the large diameter portion 624 (discharge port 624a), the second end portion 71c of the cylinder 71, the outer periphery of the plug member 72a on the Z-axis positive direction side, and the Z of the first seal member 791 A space surrounded by the surface in the positive axial direction is the first space 121. The first space 121 is prevented from communicating with the maximum diameter portion 625 side of the cylinder accommodation hole 62 by the first seal member 791. The first seal member 791 is in a state of being compressed and elastically deformed in the radial direction. The first seal member 791 applies pressure (or stress, hereinafter referred to as contact pressure) due to elastic contact between the plug member 72a and the bottom surface of the groove 720 and between the cylinder housing hole 62 and the large diameter portion 624. generate. With these contact pressures, one axial side (the first space 121 side) and the other side (the maximum diameter portion 625 side) of the first seal member 791 inside the cylinder housing hole 62 are liquid-tightly partitioned. The Inside the cylinder housing hole 62, the outer surface of the Z-axis positive direction surface 755 and the main body 75a of the flange portion 75c of the piston 75, the surface of the cylinder 71 on the Z-axis positive direction side, the medium diameter portion 623 of the cylinder housing hole 62 The space surrounded by the inner periphery of (the suction port 623a) and the surface of the second seal member 792 on the Z-axis negative direction side is the second space 122. The volume of the second space 122 changes with the reciprocation (stroke) of the piston 75 with respect to the cylinder 71. The second space 122 has a space 1221 on the outer peripheral side of the filter member 73 and a space 1222 on the inner peripheral side. The suction liquid passage 12 opens in the space 1221, and the first hole 751 of the piston 75 opens in the space 1222. The communication between the space 1221 and the cam housing hole 61 side is suppressed by the second seal member 792. In the attached state, the second seal member 792 is compressed and elastically deformed in the radial direction at the axially opposite ends of the inner and outer peripheries thereof, and between the small diameter portion 622 in the cylinder housing hole 62 and the piston 75. A contact pressure is generated between the outer periphery of (main body portion 75a). Due to these contact pressures, one side in the axial direction (cam housing hole 61 side) and the other side (second space 122 side) of the second sealing member 792 inside the cylinder housing hole 62 are liquid-tightly partitioned. The Note that brake fluid can leak from each cylinder accommodation hole 62 to the cam accommodation hole 61 via the second seal member 792. For example, the brake fluid can leak from the second space 122 through a gap between the piston 75 and the second seal member 792. The brake fluid leaking into the cam accommodation hole 61 flows into the second liquid reservoir chamber 64 via the drain liquid passage 19 and is stored in the chamber 64.

On the inner peripheral side of the cylinder 71, the space surrounded by the surface 754 of the flange 75c on the negative Z-axis side of the piston 75 and the surface on the negative Z-axis side of the flange 75c, and the inner periphery 717 of the cylinder 71, This is the third space 123. The volume of the third space 123 changes with the stroke of the piston 75. The third space 123 is prevented from communicating with the second space 122 (1222) by the third seal member 793. Similar to the squeeze packing, the third seal member 793 generates a contact pressure with the inner periphery (wall surface) 717 of the cylinder 71 by a certain compression elastic force applied in an attached state and a pressure transmitted from the sealing fluid. The outer periphery 79d of the third seal member 793 is in general contact with the inner periphery 717 of the cylinder 71 in the circumferential direction and the axial direction of the piston 75 in a range facing the inner periphery 717 of the cylinder 71 in the radial direction. The end surface 79a on the one axial side of the third seal member 793 can contact the flange portion 75c of the piston 75 as a whole in the circumferential direction of the piston 75. The end surface 79b on the other axial side of the third seal member 793 can contact the flange portion 76c of the valve case 76 as a whole in the circumferential direction of the piston 75. At the time of attachment, the third seal member 793 is compressed and elastically deformed in the axial direction between the flange portion 76c and the flange portion 75c. That is, the third seal member 793 is sandwiched between the flange portion 76c and the flange portion 75c. A third spring 783 biases the valve case 76. The end surface 79a of the third seal member 793 generates a contact pressure with respect to the surface 754 of the flange portion 75c as a whole in the circumferential direction of the piston 75. Further, the third seal member 793 is slightly compressed in the axial direction by the urging force of the third spring 783. Thus, the outer periphery 79d of the third seal member 793 generates a contact pressure with respect to the inner periphery 717 of the cylinder 71 as a whole in the circumferential direction of the piston 75. Further, when the third seal member 793 is urged to one side in the axial direction by the hydraulic pressure in the pressure chamber (third space 123), the end surface 79a of the third seal member 793 is entirely in the circumferential direction of the piston 75. Then, a (further) contact pressure with respect to the surface 754 of the flange portion 75c is generated. The third seal member 793 is slightly compressed in the axial direction by the hydraulic pressure in the pressure chamber (third space 123). Also by this, the outer periphery 79d of the third seal member 793 generates a (further) contact pressure with the inner periphery 717 of the cylinder 71 in the entire circumferential direction of the piston 75. It should be noted that the third seal member 793 does not have to be in a state of being compressed and elastically deformed in the axial direction between the flange portion 76c of the valve case 76 and the flange portion 75c of the piston 75 at the time of attachment. For example, the large diameter portion 76b2 of the valve case 76 is fixed to the end portion 75b of the piston 75 by press fitting or the like, and the third spring 783 does not bias the second seal member 792 via the valve case 76. Also good. Due to the contact pressure between the end surface 79a of the third seal member 793 and the surface 754 of the flange portion 75c, and the contact pressure between the outer periphery 79d of the third seal member 793 and the inner periphery 717 of the cylinder 71, the third pressure inside the cylinder 71 is increased. One axial side (the second space 122 side) and the other side (the third space 123 side) of the seal member 793 are partitioned liquid-tightly. In this way, the third seal member 793 separates the inside of the cylinder 71 in the direction of the movement axis of the piston 75 and functions as a high pressure seal.

The first hole 751 of the piston 75 opens in the second space 122. The second hole 752 functions as a passage connecting the first hole 751 (second space 122) and the third space 123. A suction valve 77a is provided between the passage (second hole 752) and the third space 123. The intake valve 77a switches between communication and blocking between the second hole 752 and the third space 123. The suction valve 77a is a normally closed valve, and opens the second hole 752 and the third space 123 in communication with each other. In the first space 121, a groove 723 (passage) and a discharge liquid passage 13 are opened. The

holes

711 and 712 of the cylinder 71, the second hole 722 of the plug member 72a, and the plurality of grooves 723 function as a passage connecting the third space 123 and the first space 121. This passage has a discharge valve 77b. The discharge valve 77b switches communication / blocking between the hole 712 (the third space 123 side), the hole 722, and the plurality of grooves 723 (the first space 121 side). The discharge valve 77b is a normally closed valve, and opens the hole 712 to allow the hole 722 and the plurality of grooves 723 to communicate with each other. When the piston 75 moves to one side in the axial direction (side approaching the cam housing hole 61), the volume of the third space 123 increases and the pressure of the third space 123 decreases. Brake fluid as hydraulic fluid flows from the second space 122 into the third space 123 by opening the intake valve 77a. When the piston 75 moves to the other side in the axial direction (side away from the cam housing hole 61), the volume of the second space 122 increases and the pressure of the second space 122 decreases. The working fluid flows into the second space 122 from the suction fluid path 12. Further, the volume of the third space 123 decreases, and the pressure of the third space 123 increases. The third space 123 functions as a pressure chamber that is compressed and generates a high pressure. The discharge valve 77b is opened, and the brake fluid flows from the third space 123 to the first space 121 (discharge fluid passage 13). By repeating this operation, the brake fluid is discharged from the pump portions 7A to 7E to the discharge fluid passage 13 as the piston 75 reciprocates. The brake fluid discharged from each pump unit 7A to 7E is collected in one discharge liquid passage 13, and is used in common in two systems of hydraulic circuits.

The mechanism that causes the piston 75 to reciprocate is a (eccentric) cam mechanism 70. The cam mechanism 70 converts the rotational motion of the rotary drive shaft 700 into the reciprocating motion of the piston 75. When the rotary drive shaft 700 rotates, the cam 70a rotates integrally therewith. The cam 70a functions as a driving node of the cam mechanism 70. The drive unit 70b (drive member 703) is disposed on the outer peripheral side of the cam 70a, and swings around the rotation axis O of the cam 70a (rotation drive shaft 700) by the rotation of the cam 70a. The plurality of rolling elements 701 roll around the axis O while rolling with respect to the outer circumferential surface of the cam 70a and rolling with respect to the inner circumferential surface of the driving member 703, and swing the cam 70a to drive the driving member 703. Communicate as rocking. The piston 75 is disposed around the drive member 703 and functions as a follower of the cam mechanism 70. As the drive member 703 swings, the pistons 75 of the pump portions 7A to 7E are pushed by the drive member 703 and reciprocate. The plurality of rolling elements 701 allow the relative displacement (rotation) between the cam 70a and the drive member 703, thereby suppressing the rotation of the drive member 703 accompanying the rotation of the cam 70a, and the direction around the axis O relative to the piston 75 The movement of the driving member 703 is suppressed. As a result, the drive member 703 swings without changing its posture in an ideal state. The drive member 703 is displaced (rotated) relative to the cam 70a on the inner peripheral side. The drive member 703 drives the piston 75 by pushing the piston 75 radially outward of the cam 70a (rotation drive shaft 700) on the outer peripheral side thereof. Each point (for example, each part on the outer peripheral surface 731) of the drive member 703 is a distance between the axis P and the axis O of the drive unit 70b (drive member 703) in a plane orthogonal to the axis O ( It moves on a small circle whose radius is eccentricity. Therefore, the relative displacement between the drive member 703 and the piston 75 can be suppressed within the range of the small circle, and the friction between them can be reduced. While the rotation drive shaft 700 makes one rotation, the respective portions of the drive member 703 make one rotation on the small circle. Therefore, during this time, each of the above-mentioned parts not only reciprocates a distance twice the eccentric amount in the axial direction of the piston 75, but also in a direction (circumferential direction) perpendicular to the axial center of the piston 75 with respect to the piston 75. Reciprocate twice as much as the eccentric amount. The contour curve of the cam 70a is not limited to a circular shape. As a means for allowing the relative rotation of the drive member 703, a member such as a bush constituting a sliding bearing may be provided instead of the rolling element 701. Also, instead of providing a separate member constituting the bearing, a low friction material or film is provided on the sliding portion of the cam 70a and the drive member 703 (the outer peripheral surface of the cam 70a or the inner peripheral surface of the drive member 703). May be. Further, the drive unit 70b may be omitted, and the cam 70a may directly push the piston 75.

The inner circumference 79c of the third seal member 793 partially contacts the outer circumference of the piston 75 in the circumferential direction of the piston 75 in a range facing the outer circumference of the piston 75 in the radial direction. When the third seal member 793 is viewed from the axial direction, the circumferential central portion 79c0 of each hexagonal side 79c1 of the inner periphery 79c of the third seal member 793 is a portion that contacts the piston 75 and serves as a contact portion. Function. In other words, the third seal member 793 has a contact portion 79c0 on its inner periphery 79c. There are a plurality of contact portions 79c0 on the inner periphery 79c of the third seal member 793, and they are arranged at regular intervals in the circumferential direction. The inner periphery 79c of the third seal member 793 is in contact with the outer periphery of the piston 75 at a major portion in the axial direction (range facing the outer periphery of the piston 75 in the radial direction) at each contact portion 79c0. The outer periphery of the main body 75a1 of the piston 75 is in contact with each contact portion 79c0 of the third seal member 793 substantially in the axial direction (range facing the inner periphery 79c of the third seal member 793 in the radial direction). . With the third seal member 793 attached, at least the contact portion 79c0 and its vicinity are in a state of being compressed and elastically deformed at least in the radial direction, and contact pressure is generated between the contact portion 79c0 and the outer peripheral surface of the piston 75. To do. The compressive elastic force of the contact portion 79c0 is an additional contact between the portion 79d0 on the outer periphery 79d of the third seal member 793 on the radial straight line passing through the contact portion 79c0 and its vicinity and the inner periphery 717 of the cylinder 71. Generate pressure. In the outer periphery 79d of the third seal member 793, the contact pressure between the portion 79d1 sandwiched in the circumferential direction by the portion 79d0 and the inner periphery 717 of the cylinder 71 is the contact pressure between the portion 79d0 and the inner periphery 717 of the cylinder 71. Smaller than.

There is a slight gap between the outer periphery of the flange portion 75c of the piston 75 and the inner periphery 717 of the cylinder 71. Within this gap, the flange portion 75 c of the piston 75 can move in the radial direction with respect to the cylinder 71. This radial movement may cause the piston 75 to vibrate. The drive unit 70b moves (reciprocates) relative to the end surface 750 of the piston 75 in the radial direction of the piston 75. A radial force acts on the end surface 750 from the drive unit 70b (drive member 703). As a result, when the piston 75 reciprocates in the axial direction with respect to the cylinder 71, at the same time, the piston 75 moves in the radial direction (reciprocating) with respect to the cylinder 71, and there is a high possibility that the piston 75 swings (oscillates). As a result, vibration of the pump 7 occurs, and the silence of the pump 7 may be reduced. The inner periphery 79c of the third seal member 793 contacts (even partially) the outer periphery of the piston 75. Therefore, unlike the case where the inner periphery 79c of the third seal member 793 does not contact the outer periphery of the piston 75, the piston 75 is held by the cylinder 71 via the third seal member 793. In other words, the radial position of the outer periphery of the piston 75 (flange portion 75c) with respect to the inner periphery 717 of the cylinder 71 is regulated by the third seal member 793. Therefore, since the radial movement of the piston 75 is suppressed, the vibration of the piston 75 is suppressed.

While the rotation drive shaft 700 makes one rotation, the piston 75 includes a force due to the discharge pressure, an urging force of the third spring 783, and a piston 75 (including a third seal member 793) against the cylinder 71. Hereinafter, referred to as a piston 75 or the like. )) And the frictional force. When the frictional force increases, the torque of the rotary drive shaft 700 for driving the piston 75 (hereinafter referred to as drive torque) increases. The frictional force may increase due to variations in dimensions of parts to be assembled, temperature changes during operation, etc., and drive torque may increase. In particular, when the piston 75 is held in the cylinder 71 via the third seal member 793, the third seal member 793 and the cylinder 71 are equivalent to the amount that the third seal member 793 generates a contact pressure with the outer periphery of the piston 75. An additional contact pressure (in addition to the contact pressure for ensuring the sealing performance) is generated between the inner periphery 717 and the inner periphery 717. Thereby, there exists a possibility that the said friction force may increase. Since the material of the third seal member 793 includes a solid lubricant, the third seal member 793 (outer periphery 79d in sliding contact with the cylinder 71) has lubricity. Since the frictional force is reduced, an increase in driving torque can be suppressed. In order to obtain this function and effect, the material of the third seal member 793 (of which the outer periphery 79d slidably contacting the cylinder 71) may be a solid material having self-lubricating properties, and is not limited to PTFE. Further, a lubricating film may be provided on the outer periphery 79d of the third seal member 793 that is in sliding contact with the cylinder 71.

The inner periphery 79c of the third seal member 793 partially contacts the outer periphery of the piston 75 (in a range facing the outer periphery of the piston 75 in the radial direction). Therefore, the third seal member 793 has a compression elasticity in the third seal member 793 as compared with the case where the inner periphery 79c of the third seal member 793 is in total contact with the outer periphery of the piston 75 (in a range facing the outer periphery of the piston 75 in the radial direction). A portion with a large amount of deformation decreases (a portion with a small amount of compressive elastic deformation increases). As a result, the portion of the outer periphery 79d of the third seal member 793 where the contact pressure with respect to the inner periphery 717 of the cylinder 71 is large (additional contact pressure is generated) is reduced. In other words, the portion where the contact pressure (the pressing force of the third seal member 793 against the inner periphery 717 of the cylinder 71) is small increases. Accordingly, since the frictional force between the outer periphery 79d of the third seal member 793 and the inner periphery 717 of the cylinder 71 is reduced as a whole, the frictional force of the piston 75 and the like against the cylinder 71 is reduced. Even if there is a dimensional variation of each part, the increase in the frictional force is suppressed. As a result, an increase in driving torque is suppressed, so that energy loss can be suppressed. In other words, it is possible to achieve both suppression of vibration of the piston 75 and suppression of increase in drive torque.

The inner circumference 79c of the third seal member 793 partially contacts the outer circumference of the piston 75 in the circumferential direction of the piston 75 (in a range facing the outer circumference of the piston 75 in the radial direction). Therefore, it is possible to more effectively achieve both suppression of vibration of the piston 75 and suppression of increase in driving torque.

The contact portion 79c0 is a portion that contacts the outer periphery of the piston 75 regardless of the position of the piston 75 relative to the piston 75 in the circumferential direction, and is the contact portion 79c0 on the seal member side. Therefore, in order for the third seal member 793 to partially contact the outer periphery of the piston 75 in the circumferential direction of the piston 75, the inner periphery 79c of the third seal member 793 in the circumferential direction of the piston 75 Changing the shape is sufficient. As a result, the outer periphery of the piston 75 can have a simple shape (cylindrical shape) in the circumferential direction at least in a range facing the inner periphery 79c of the third seal member 793 in the radial direction. Therefore, the productivity of the piston 75 (and hence the pump 7, the same applies hereinafter) can be improved.

Specifically, the contact portion 79c0 is located on each side 79c1 of the hexagon as viewed from the axial direction of the third seal member 793 (the moving axis direction of the piston 75). The hexagon is a polygon. Therefore, the inner periphery 79c of the third seal member 793 can be easily molded (for example, can be molded), and the contact portion 79c0 can be easily provided. For this reason, the productivity of the third seal member 793 (and hence the pump 7, the same applies hereinafter) can be improved. Further, since the number of contact portions 79c0 is three or more, the contact pressure is dispersed in the circumferential direction and the balance of contact pressure is improved as compared with the case where the number of contact portions 79c0 is two or less. Therefore, the radial position of the piston 75 can be regulated more stably, the piston holding performance can be improved, and the sealing performance can be stabilized. The contact portion 79c0 is not limited to a hexagon, and may be on each side of an arbitrary polygon. The sides of these polygons are not limited to straight lines, and may be curves that are convex in the direction away from the axis of the third seal member 793 or convex in the direction of approaching the axis of the third seal member 793. Also in these cases, the side can function as the contact portion 79c0. In the present embodiment, since the side 79c1 is a straight line, it is easy to form the side (side surface) 79c1 on the inner periphery 79c of the third seal member 793, and the contact portion 79c0 can be easily provided. Note that when the side is a convex curve in a direction approaching the axial center of the third seal member 793, the side makes more positive contact with the outer periphery of the piston 75. Therefore, the piston 75 is more securely held in the cylinder 71, and the radial position of the piston 75 with respect to the cylinder 71 is regulated. Therefore, the vibration of the piston 75 is more effectively suppressed. When the side is a convex curve in a direction away from the axis of the third seal member 793, the angle between the sides adjacent in the circumferential direction (angle at the vertex of the polygon) is large. Therefore, even when there is an upper limit on the outer diameter of the third seal member 793, the thickness of the thinnest portion of the third seal member 793 in the radial direction (the third seal member 793 on the radial straight line passing through the apex of the polygon) In other words, the distance from the corner portion of the inner periphery 79c of the third seal member 793 to the outer periphery 79d of the third seal member 793 (the thickness of the inner and outer diameters) can be easily set to a certain value or more. Therefore, since the radial thickness of the third seal member 793 can be ensured even at the thinnest portion, the durability and formability (workability) of the third seal member 793 can be improved.

In the present embodiment, the polygon is a hexagon. Therefore, compared with the case where the polygon is a pentagon, for example, the angle formed by each side 79c1 adjacent to the polygon (the angle at the vertex 79c2) can be increased. Therefore, it is easier to set the thickness of the thinnest portion of the third seal member 793 in the radial direction to a certain value or more. In addition, the number of polygon sides 79c1 (contact portions 79c0) is larger than when the polygon is, for example, a pentagon. Therefore, the contact pressure is more dispersed in the circumferential direction, and the balance of the contact pressure is further improved. The number of hexagonal sides 79c1 (vertices 79c2) is 6, that is, an even number. In other words, the hexagon is an even square. Therefore, the moldability of the third seal member 793 can be improved compared to the case of an odd-numbered square. The hexagon is a regular hexagon. A regular hexagon is a regular polygon. Therefore, the thickness of the thinnest portion of the third seal member 793 can be made uniform. Thereby, the sealing performance and durability of the third seal member 793 can be improved. Further, the shape of the inner periphery 79 c of the third seal member 793 is symmetric in the direction around the axis of the third seal member 793. In other words, the contact portion 79c0 is positioned symmetrically with respect to the axis of the third seal member 793. As a result, the contact pressure is more evenly distributed in the circumferential direction and the balance of the contact pressure is improved, so that the piston holding performance and the sealing performance can be further improved.

The drive source of the pump 7 is not limited to the motor 7a but may be an internal combustion engine or the like. In the present embodiment, the use of the electric motor 7a, which is more quiet than the other drive sources, as the drive source of the pump 7, makes the effect of improving the sound vibration of the pump 7 stand out. Further, the pump 7 may be used in a device other than the brake device. In the present embodiment, by using the pump 7 in the brake device, vibration and noise when brake control is performed by the operation of the pump 7 can be reduced, and the uncomfortable feeling given to the driver can be reduced.

[Second Embodiment]
First, the configuration will be described with reference to FIG. 10 and FIG. FIG. 10 is an exploded perspective view similar to FIG. 7, including the third seal member 793 of the present embodiment. FIG. 11 is a cross-sectional view similar to FIG. 8, including the third seal member 793 of the present embodiment. The inner periphery 79c of the third seal member 793 is a regular pentagon when viewed from the axial direction of the third seal member 793. In other words, the inner circumference 79c of the third seal member 793 is each side surface of a right prism having a regular pentagonal bottom surface, and each side surface is rectangular. The (shortest) distance from the axial center of the third seal member 793 to each side (side surface) 79c1 of the regular pentagon is slightly shorter than the distance (radius) from the axial center of the piston 75 to the outer periphery of the main body 75a1. The distance from the axial center of the third seal member 793 to each vertex 79c2 of the regular pentagon, in other words, the boundary line (connection part) 79c2 of each side surface 79c1 is longer than the radius of the main body 75a1. A substantial center portion of each pentagonal side 79c1 of the inner periphery 79c of the third seal member 793 when the third seal member 793 is viewed from the axial direction functions as the contact portion 79c0 (on the seal member side). Since other configurations are the same as those of the first embodiment, members common to the first embodiment are denoted by the same reference numerals as those of the first embodiment, and description thereof is omitted.

Next, the operational effects will be described. The inner periphery 79c is a polygon when viewed from the axial direction of the third seal member 793, and this polygon is a pentagon. Therefore, there are five contact portions 79c0. The number of contact portions 79c0 is smaller than when the polygon is a hexagon, for example. In other words, the number of portions where additional contact pressure is generated on the outer periphery 79d of the third seal member 793 is small. As a result, the frictional force of the piston 75 or the like with respect to the cylinder 71 is reduced, so that an increase in driving torque can be further suppressed. In addition, the thickness of the thinnest portion of the third seal member 793 in the radial direction can be ensured as compared with the case where the polygon is a triangle or a rectangle. Other functions and effects are the same as those of the first embodiment.

[Third embodiment]
First, the configuration will be described with reference to FIG. 12 and FIG. FIG. 12 is an exploded perspective view similar to FIG. 7, including the third seal member 793 of the present embodiment. FIG. 13 is a cross-sectional view similar to FIG. 8, including the third seal member 793 of the present embodiment. The third seal member 793 has a seal body and a protrusion 79c3. The inner periphery 793c of the seal body has a cylindrical shape substantially concentric with the outer periphery 79d of the third seal member 793. There are a plurality (eight) protrusions 79c3 on the inner periphery 79c of the third seal member 793, and they are arranged at equal intervals in the circumferential direction of the third seal member 793. The protrusion 79c3 is integrated with the seal body (as one component) and protrudes radially inward from the inner periphery 793c of the seal body. The protrusion 79c3 has a prismatic shape extending in the axial direction of the third seal member 793, and has one side surface 79c30 extending in the circumferential direction and two side surfaces 79c31 and 79c32 extending in the radial direction. Each of the side surfaces 79c30 to 79c32 is planar. The protrusion 79c3 extends over the entire axial range of the third seal member 793. The axial end surface of the protrusion 79c3 constitutes the same plane as the axial end surfaces 79a and 79b of the seal body. The outer diameter of the seal body is substantially the same as or slightly larger than the inner diameter of the cylinder 71. The inner diameter of the seal main body (the diameter of the inner periphery 793c) is slightly larger than the outer diameter of the main body 75a1 of the piston 75. The (shortest) distance from the axial center of the third seal member 793 to the side surface 79c30 of the protrusion 79c3 is slightly shorter than the distance (radius) from the axial center of the piston 75 to the outer peripheral surface of the main body 75a1. Since other configurations are the same as those of the first embodiment, members common to the first embodiment are denoted by the same reference numerals as those of the first embodiment, and description thereof is omitted.

Next, the operational effects will be described. The protrusion 79c3 (side surface 79c30) functions as a contact portion 79c0 that comes into contact with the main body portion 75a1 of the piston 75. The inner periphery 79c of the third seal member 793 is substantially entirely in the axial direction at each projection 79c3 and partially in the circumferential direction of the piston 75 (in a range facing the outer periphery of the main body 75a1 in the radial direction). The piston 75 comes into contact with the outer periphery. The inner periphery 79c of the third seal member 793 does not contact the outer periphery of the piston 75 in a recess sandwiched between the protrusions 79c3 adjacent in the circumferential direction of the piston 75. The contact portion 79c0 is a contact portion 79c0 on the seal member side, and is positioned symmetrically with respect to the axis of the third seal member 793. The contact portion 79c0 is a protrusion 79c3 that protrudes radially inward from the inner periphery 793 c of the seal body. Therefore, the inner periphery 79c of the third seal member 793 comes into more active contact with the outer periphery of the piston 75 at the contact portion 79c0. By this contact, the piston 75 is more securely held in the cylinder 71, and the radial position of the piston 75 with respect to the cylinder 71 is regulated. Note that the shape of the protrusion 79c3 is arbitrary, and is not limited to a prism shape, for example, and each side surface thereof may be a curved surface. Further, the number of protrusions 79c3 is not limited to eight. The dimension (length) in the axial direction of the protrusion 79c3 and the width in the circumferential direction of the protrusion 79c3 (or the interval between the protrusions 79c3) are also arbitrary. The protrusions 79c3 may be provided discontinuously (plural) in the axial direction of the third seal member 793. The protrusion 79c3 is integral with the seal body. Therefore, the number of parts can be reduced and the assembling property of the third seal member 793 can be improved as compared with the case where the projection 79c3 is separate from the seal body. Other functions and effects are the same as those of the first embodiment.

[Fourth embodiment]
First, the configuration will be described with reference to FIG. 14 and FIG. FIG. 14 is an exploded perspective view similar to FIG. 7, including the third seal member 793 of the present embodiment. FIG. 15 is a cross-sectional view similar to FIG. 8, including the third seal member 793 of the present embodiment. The third seal member 793 has a seal body and an interposition member 79c4. The seal main body is a main body portion of the third seal member 793, and an inner periphery 793c thereof has a cylindrical shape substantially concentric with the outer periphery 79d of the third seal member 793. The interposed member 79c4 is a separate member separated from the seal body. There are a plurality (three) of interposed members 79c4 on the inner periphery 79c of the third seal member 793, and the interposed members 79c4 are arranged so as to be arranged at substantially equal intervals in the circumferential direction of the third seal member 793. The interposed member 79c4 has a columnar shape and is disposed so as to extend in the axial direction of the third seal member 793. The axial dimension of the interposed member 79c4 is substantially the same as the axial dimension of the seal body. The interposed member 79c4 is disposed such that the outer periphery thereof is in contact with the inner periphery 793c of the seal body over the entire axial range of the third seal member 793. The interposed member 79c4 is disposed such that its axial end surface forms the same plane as the axial end surfaces 79a and 79b of the seal body. The outer diameter of the seal body is substantially the same as or slightly larger than the inner diameter of the cylinder 71. The inner diameter of the seal main body (the diameter of the inner periphery 793c) is slightly larger than the outer diameter of the main body 75a1 of the piston 75. The diameter of the interposed member 79c4 is slightly larger than the distance from the outer periphery of the main body 75a1 to the inner periphery 793c of the seal body when the piston 75 and the third seal member 793 are coaxial.

¡The outer periphery of the seal body contacts the inner periphery 717 of the cylinder 71. The outer periphery of the interposed member 79c4 is in contact with the inner periphery 793c of the seal body on the side far from the axis of the third seal member 793, and on the side close to the axis of the third seal member 793, Contact the outer periphery. The interposition member 79c4 (the side close to the axis of the third seal member 793) functions as a contact portion 79c0 that contacts the piston 75 (on the seal member side). The inner circumference 79c of the third seal member 793 is partly in the circumferential direction of the piston 75 in each interposed member 79c4 substantially in the axial direction and (in the range facing the outer circumference of the main body 75a1 in the radial direction). In addition, it contacts the outer periphery of the piston 75. The inner periphery 79c of the third seal member 793 does not contact the outer periphery of the piston 75 in a gap between the interposed members 79c4 adjacent in the circumferential direction of the piston 75. The contact portion 79c0 is a contact portion on the seal member side, and is disposed substantially symmetrically with respect to the axis of the third seal member 793. Since other configurations are the same as those of the first embodiment, members common to the first embodiment are denoted by the same reference numerals as those of the first embodiment, and description thereof is omitted.

Next, the operational effects will be described. The interposed member 79c4 is disposed so as to protrude radially inward with respect to the inner periphery 793c of the seal body. Therefore, the inner periphery 79c of the third seal member 793 is more positively brought into contact with the outer periphery of the piston 75 at the contact portion 79c0 (interposition member 79c4). Note that the shape of the interposed member 79c4 is arbitrary, and is not limited to a cylindrical shape, and may be, for example, a prismatic shape. Further, the number of the interposition members 79c4 is not limited to three, and the dimension (length) in the axial direction of the interposition members 79c4 and the width in the circumferential direction of the interposition members 79c4 (or the interval between the interposition members 79c4) are also arbitrary. The interposed member 79c4 may be provided discontinuously (plural) in the axial direction of the third seal member 793. The interposed member 79c4 is a separate body from the seal body. Therefore, compared to the case where the interposition member 79c4 is integrated with the seal body, the inner periphery 793c of the seal body can be formed in a simple shape (cylindrical shape) in the circumferential direction, and the productivity of the seal body can be improved. In addition, the design freedom of the shape and properties of the interposition member 79c4 that functions as the contact portion 79c0 can be improved. For example, the interposition member 79c4 is formed of a softer material (rubber or the like) than the seal body. Thereby, an additional contact pressure with the inner periphery 717 of the cylinder 71 at the outer periphery 79d of the third seal member 793 can be reduced while holding the piston 75. Other functions and effects are the same as those of the first embodiment.

[Fifth Embodiment]
First, the configuration will be described with reference to FIGS. FIG. 16 is an exploded perspective view similar to FIG. 7, including the third seal member 793 of the present embodiment. FIG. 17 is a cross-sectional view similar to FIG. 8, including the third seal member 793 of the present embodiment. The inner periphery 79c of the third seal member 793 is a regular hexagon when viewed from the axial direction. Each vertex 79c2 of the regular hexagon has a curve (R). Between each side (side surface) 79c1 and the outer periphery 79d of the inner periphery 79c of the third seal member 793, there is a hole (hollow) 79e. The hole 79e extends in the axial direction and penetrates the third seal member 793. That is, the hole 79e opens in both axial end surfaces 79a and 79b of the third seal member 793. The hole 79e has a flat shape and extends substantially parallel to each side surface 79c1. In the circumferential direction of the third seal member 793, the dimension of the hole 79e is smaller than the dimension of the side surface 79c1. In the circumferential direction, the center of the hole 79e is substantially at the same position as the center of the side surface 79c1. There is a hole 79e on the outer side in the radial direction of the side surface 79c1 excluding both ends in the circumferential direction (on the central side in the circumferential direction). There are no holes 79e on the radially outer side of the side surface 79c1 in the circumferential direction at both ends in the circumferential direction (connection portions between adjacent side surfaces 79c1) 79c2, and this portion is solid. When the third seal member 793 is viewed from the axial direction, the central portion in the circumferential direction on each side 79c1 of the inner periphery 79c functions as a contact portion 79c0 that contacts the piston 75 (on the seal member side). The third seal member 793 has a hole 79e between its outer periphery 79d and the contact portion 79c0. Since other configurations are the same as those of the first embodiment, members common to the first embodiment are denoted by the same reference numerals as those of the first embodiment, and description thereof is omitted.

Next, the operational effects will be described. The compression elastic deformation of the contact portion 79c0 due to the contact with the outer periphery of the piston 75 (main body portion 75a1) is so-called absorbed by the hole 79e, and the deformation is less likely to be transmitted radially outward than the hole 79e. The compression elastic force of the contact portion 79c0 is an additional contact pressure between the portion 79d0 on the radial straight line passing through the contact portion 79c0 and its vicinity and the inner periphery 717 of the cylinder 71 on the outer periphery 79d of the third seal member 793. Generation | occurrence | production of is suppressed by the hole 79e. Accordingly, the frictional force of the piston 75 and the like with respect to the cylinder 71 is reduced, so that an increase in driving torque can be further suppressed. If there is at least a part of the hole 79e on the radial straight line passing through the contact portion 79c0, the above-described operation can be obtained more effectively. The hole 79e may not penetrate the third seal member 793 in the axial direction, and may occupy a part of the third seal member 793 in the axial direction inside the third seal member 793. The shape of the hole 79e is arbitrary, and may be an ellipse or the like when viewed from the axial direction. The number of holes 79e is arbitrary, and two or more holes 79e (in the circumferential direction or the axial direction) may be arranged on one side surface 79c1. There may be a side surface of the polygonal side surface 79c1 where the hole 79e is not disposed. In the third seal member 793, a material having a smaller elastic modulus in the radial direction than other portions may be disposed at a portion on the radial straight line passing through the contact portion 79c0 in place of the hole 79e. Other functions and effects are the same as those of the first embodiment.

[Sixth embodiment]
First, the configuration will be described with reference to FIGS. FIG. 18 is an exploded perspective view similar to FIG. 7, including the third seal member 793 and the piston 75 of the present embodiment. FIG. 19 is a plan view of the piston 75 assembled with the third seal member 793 and the cylinder 71 that accommodates the piston 75 including the end surface 79b of the third seal member 793 and perpendicular to the axis Q. A cut section is shown. FIG. 19 corresponds to a cross section taken along line XIX-XIX in FIG. 20 is a cross-sectional view similar to FIG. 9, including the third seal member 793 and the piston 75 of the present embodiment. The outer periphery of the main body 75a1 on the other axial side of the flange 75c of the piston 75 is polygonal when viewed from the axial direction of the piston 75. Specifically, it is a regular hexagon. In other words, the outer periphery of the main body 75a1 of the piston 75 is each side surface 75a2 of a right prism having a regular hexagonal bottom surface. The inner periphery 79c of the third seal member 793 has a cylindrical shape substantially concentric with the outer periphery 79d. The (shortest) distance from the axis of the piston 75 to each side surface (each side of the regular hexagon) 75a2 is shorter than the distance (radius) from the axis of the third seal member 793 to the inner periphery 79c. The distance from the axial center of the piston 75 to each vertex 75a3 of the regular hexagon, in other words, the boundary line (connection part) 75a3 of each side surface 75a2, is slightly longer than the radius of the inner periphery 79c of the third seal member 793. Since other configurations are the same as those of the first embodiment, members common to the first embodiment are denoted by the same reference numerals as those of the first embodiment, and description thereof is omitted.

Next, the operational effects will be described. The inner periphery 79c of the third seal member 793 partially contacts the outer periphery of the piston 75 in the circumferential direction of the piston 75 in a range facing the outer periphery of the piston 75 (main body portion 75a1) in the radial direction. When the piston 75 is viewed from the axial direction, each of the hexagonal apexes (boundary lines of the side surfaces 75a2) 75a3 of the main body 75a1 and its vicinity (75a0) in the circumferential direction are located on the inner periphery 79c of the third seal member 793. It is a part which contacts and functions as a contact part. In other words, the piston 75 has a contact portion 75a0 on its outer periphery. There are a plurality of contact portions 75a0 on the outer periphery of the piston 75, and they are arranged at regular intervals in the circumferential direction. Each contact portion 75a0 is substantially in contact with the inner periphery 79c of the third seal member 793 in the axial direction. In a state in which the third seal member 793 is attached, at least a portion of the inner periphery 79c of the third seal member 793 that contacts the contact portion 75a0 and its vicinity are in a state of being compressed and elastically deformed at least in the radial direction. Contact pressure is generated between the contact portion 75a0 of the member 793 and the contact portion 75a0. The compressive elastic force of the above portion is an additional contact pressure between the portion 79d0 on the outer periphery 79d of the third seal member 793 on the radial straight line passing through the contact portion 75a0 and its vicinity and the inner periphery 717 of the cylinder 71. Is generated. In the outer periphery 79d of the third seal member 793, the contact pressure between the portion 79d1 sandwiched in the circumferential direction by the portion 79d0 and the inner periphery 717 of the cylinder 71 is the contact pressure between the portion 79d0 and the inner periphery 717 of the cylinder 71. Smaller than.

The contact portion 75a0 is a contact portion on the piston side, and is a portion that contacts the inner periphery 79c of the third seal member 793 regardless of the position of the piston 75 in the circumferential direction with respect to the third seal member 793. Therefore, in order to make the piston 75 partially contact with the inner circumference 79c of the third seal member 793 in the circumferential direction of the piston 75, the shape of the outer circumference of the piston 75 (main body portion 75a1) in the circumferential direction. It is enough to change. Therefore, the inner circumference 79c of the third seal member 793 can be a simple shape (cylindrical shape) in the circumferential direction at least in the range facing the outer circumference of the piston 75 in the radial direction, and the productivity of the third seal member 793 is increased. Can be improved.

Specifically, the contact portion 75a0 is a polygonal vertex 75a3 and its vicinity as seen from the moving axis direction of the piston 75, and includes the polygonal vertex 75a3.
Therefore, the contact portion 75a0 can be easily formed on the outer periphery of the piston 75, and the contact portion 75a0 can be easily provided, so that the productivity of the piston 75 can be improved. The polygon is not limited to a hexagon, and may be a pentagon, for example. The outer periphery of the piston 75 may have a protrusion or an interposed member extending in the axial direction of the piston 75 as the contact portion 75a0. Each vertex of the polygon, in other words, a boundary line (connection part) on each side surface of the main body 75a1 may be provided with a curve (R). Other functions and effects are the same as those of the first embodiment.

[Seventh embodiment]
First, the configuration will be described with reference to FIGS. FIG. 21 is an exploded perspective view similar to FIG. 7, including the third seal member 793 of the present embodiment. FIG. 22 is a cross-sectional view of the end of the piston 75 assembled with the valve case 76, the first ball 771, the first spring 781, and the third seal member 793 of the present embodiment, cut by a plane including its axis. Indicates. The inner periphery 79c of the third seal member 793 has a cylindrical shape with a step in the axial direction. The inner periphery 79c has a large diameter part 79c5 and a small diameter part 79c6. The large-diameter portion 79c5 and the small-diameter portion 79c6 have a cylindrical shape substantially concentric with the outer periphery 79d of the third seal member 793, and the small-diameter portion 79c6 has a smaller diameter than the large-diameter portion 79c5. The diameter of the small diameter portion 79c6 is slightly smaller than the diameter of the main body portion 75a1 of the piston 75. The diameter of the large diameter part 79c5 is larger than the diameter of the main body part 75a1. The large-diameter portion 79c5 and the small-diameter portion 79c6 have the same axial dimension, or the small-diameter portion 79c6 has a slightly smaller axial dimension than the large-diameter portion 79c5. In other words, the axial dimension of the small diameter portion 79c6 is less than or equal to half of the overall axial dimension of the third seal member 793. The axial dimension of the small diameter part 79c6 is smaller than the axial dimension of the main body part 75a1. The small-diameter portion 79c6 is on one side in the axial direction of the third seal member 793, and opens on the end surface 79a on one side in the axial direction of the third seal member 793. The large diameter portion 79c5 is on the other axial side of the third seal member 793, and opens to the end surface 79b on the other axial side of the third seal member 793. The third seal member 793 is such that one side in the axial direction (small diameter portion 79c6) is on the side close to the flange portion 75c of the piston 75 and the other side in the axial direction (large diameter portion 79c5) is on the side far from the flange portion 75c. The piston 75 is installed. The end surface 79a of the third seal member 793 can contact the surface 754 of the flange portion 75c as a whole in the circumferential direction of the piston 75. Since other configurations are the same as those of the first embodiment, members common to the first embodiment are denoted by the same reference numerals as those of the first embodiment, and description thereof is omitted.

Next, the operational effects will be described. The inner periphery 79c of the third seal member 793 partially contacts the outer periphery of the piston 75 in the moving axis direction of the piston 75. The small diameter portion 79c6 functions as a contact portion 79c0 that is a portion that contacts the piston 75 (on the seal member side). In other words, the third seal member 793 has a contact portion 79c0 on its inner periphery 79c. The inner circumference 79c is in contact with the outer circumference of the piston 75 (main body 75a1) at the small diameter portion 79c6 in the circumferential direction. The small diameter portion 79c6 contacts the outer periphery of the piston 75 in the entire axial range. The outer periphery of the piston 75 (main body portion 75a1) faces the inner periphery 79c of the third seal member 793 in the entire axial range, and a part in the axial direction contacts the small diameter portion 79c6. The third seal member 793 is in a state in which at least the small diameter portion 79c6 and its vicinity are compressed and elastically deformed at least in the radial direction in the attached state, and between the small diameter portion 79c6 and the outer periphery of the piston 75 (main body portion 75a1). Contact pressure is generated. The compression elastic force of the small diameter part 79c6 generates an additional contact pressure between the outer periphery 79d of the third seal member 793 and the inner periphery 717 of the cylinder 71. On the other hand, the large-diameter portion 79c5 of the third seal member 793 and its vicinity do not contact the outer periphery of the piston 75, so that the compression elastic deformation of this portion is suppressed. The contact pressure between the portion 79d0 that overlaps the small-diameter portion 79c6 in the axial direction (as viewed from the radial direction) and the inner periphery 717 of the cylinder 71 on the outer periphery 79d of the third seal member 793 is axially (as viewed from the radial direction). The contact pressure between the portion 79d1 overlapping the large diameter portion 79c5 and the inner periphery 717 of the cylinder 71 is smaller. This reduces the portion of the outer periphery 79d of the third seal member 793 where the contact pressure with the inner periphery 717 of the cylinder 71 is large (additional contact pressure is generated). As a whole, the frictional force with the inner circumference 717 is reduced. Therefore, the frictional force of the piston 75 etc. against the cylinder 71 is reduced.

The inner periphery 79c of the third seal member 793 partially contacts the outer periphery of the piston 75 in the moving axis direction of the piston 75 in a range facing the outer periphery of the piston 75 (main body portion 75a1) in the radial direction. The axial dimension of the contact part 79c0 (small diameter part 79c6) is less than or equal to half the axial dimension of the third seal member 793. Therefore, the inner periphery 79c of the third seal member 793 contacts the outer periphery of the piston 75 in the (moving) axial direction of the piston 75 in a range in which the inner periphery 79c faces the outer periphery of the piston 75 (main body portion 75a1) in the radial direction. The range of the portion is suppressed to a certain level or less. For this reason, in the outer periphery 79d of the third seal member 793, the range of the portion 79d0 where the contact pressure with respect to the inner periphery 717 of the cylinder 71 is large (additional contact pressure is generated) becomes a certain level or less. Therefore, the frictional force of the piston 75 etc. against the cylinder 71 is more effectively reduced.

Note that the inner periphery 79c of the third seal member 793 may not only partially contact the outer periphery of the piston 75 in the axial direction but also partially contact in the circumferential direction. For example, the portion corresponding to the small-diameter portion 79c6 of the third seal member 793 is a polygonal column shape, or a protrusion or unevenness (integrated with the third seal member 793) extending in the axial direction or separate from the third seal member 793. Or an intervening member, and may have a region that does not partially contact the outer periphery of the piston 75 in the circumferential direction. In the present embodiment, the inner periphery 79c of the third seal member 793 contacts the outer periphery of the piston 75 (main body portion 75a1) in the circumferential direction of the piston 75 at the contact portion 79c0 (small diameter portion 79c6). . The compression elastic force of the contact portion 79c0 generates an additional contact pressure with the inner periphery 717 of the cylinder 71 in the entire circumferential range of the outer periphery 79d (part 79d0) of the third seal member 793. Therefore, the sealing performance of the third seal member 793 is improved. Further, the shape of the inner periphery 79c of the third seal member 793 can be made uniform over the entire circumferential range. At least the inner periphery 79c of the small-diameter portion 79c6 can have a simple shape (annular shape) in the circumferential direction. Therefore, the productivity of the third seal member 793 can be improved. The shape of the portion (large diameter portion 79c5) that does not contact the outer periphery of the piston 75 on the inner periphery 79c of the third seal member 793 is arbitrary. In the present embodiment, the shape of this portion (large diameter portion 79c5) is also a simple shape (cylindrical shape). Therefore, the productivity of the third seal member 793 can be improved.

The inner periphery 79c of the third seal member 793 may have a plurality of contact portions 79c0 (small diameter portions 79c6) or non-contact portions (large diameter portions 79c5) with the piston 75 in the axial direction. The shape of the inner periphery of the small diameter portion 79c6 cut by a plane passing through the axis of the third seal member 793 is convex in a direction away from the axis of the third seal member 793 or in a direction approaching the axis of the third seal member 793. It may be a convex curve. In other words, the inner periphery 79c of the third seal member 793 may have irregularities extending partially in the axial direction in the circumferential direction. Also in these cases, the portion closest to the axial center on the inner periphery 79c of the third seal member 793 can function as a contact portion 79c0 that partially contacts the outer periphery of the piston 75 in the moving axis direction of the piston 75. . In addition, the inner periphery 79c of the third seal member 793 has, as a contact portion 79c0, a protrusion (integrated with the third seal member 793) extending in the circumferential direction or an interposition member (separate from the third seal member 793) as a shaft. You may have partial in direction.

The contact portion 79c0 is a portion that contacts the outer periphery of the piston 75 regardless of the position of the piston 75 relative to the piston 75 in the movement axis direction, and is a contact portion on the seal member side. Therefore, in order for the third seal member 793 to partially contact the outer periphery of the piston 75 in the moving axis direction of the piston 75, the third seal member in the axial direction of the third seal member 793 is used. It is sufficient to change the shape of the inner periphery 79c of 793. Therefore, when the outer periphery of the piston 75 (main body portion 75a1) is cut in a simple shape in the axial direction (at a plane passing through the axial center of the piston 75) at least in the range facing the inner periphery 79c of the third seal member 793 in the radial direction. Linear), and the productivity of the piston 75 can be improved. In the present embodiment, the contact portion 79c0 (small diameter portion 79c6) has a simple shape (annular shape) in the circumferential direction. Therefore, the outer periphery of the main body portion 75a1 that is in general contact with the contact portion 79c0 in the circumferential direction can have a simple shape in the axial direction (linear shape when cut by a plane passing through the axis of the piston 75). The outer periphery of the piston 75 may have a contact portion that partially contacts the inner periphery 79c of the third seal member 793 in the moving axis direction of the piston 75. This contact portion is a portion that contacts the inner periphery 79c of the third seal member 793 regardless of the position of the piston 75 in the movement axis direction with respect to the third seal member 793, and is a piston-side contact portion. For example, the outer periphery of the main body portion 75a1 may have a step having a different diameter, an unevenness or a protrusion (extending in the circumferential direction), or an interposition member extending in the circumferential direction (as a part of the main body portion 75a1). Also good. In these cases, the inner periphery 79c has a simple shape in the axial direction (straight when cut by a plane passing through the axial center of the third seal member 793) at least in a range facing the outer periphery of the main body 75a1 in the radial direction. be able to.

The small diameter part 79c6 is on the side close to the flange part 75c. Therefore, unlike the case where the small diameter portion 79c6 is on the side far from the flange portion 75c, the entire range in the axial direction of the small diameter portion 79c6 can contact the outer periphery of the piston 75 (main body portion 75a1). For this reason, compared with the above case, the range in which additional contact pressure is generated between the outer periphery 79d of the third seal member 793 and the inner periphery 717 of the cylinder 71 due to the compression elastic force of the small diameter portion 79c6 is wide. Therefore, the sealing performance of the third seal member 793 is improved. Further, when the third seal member 793 is urged in one axial direction by the hydraulic pressure in the pressure chamber (the third space 123), the end surface 79a on the one axial side of the third seal member 793 is formed on the flange portion 75c. A (further) contact pressure against surface 754 is generated. Here, the small diameter portion 79c6 opens in the end face 79a. Therefore, compared with the case where the large-diameter portion 79c5 opens to the end surface 79a, the area of the end surface 79a that contacts the surface 754 is large, so the range in which the contact pressure due to the hydraulic pressure is generated is wide. Therefore, the sealing performance of the third seal member 793 is improved. The boundary (corner portion) between the small diameter portion 79c6 and the end surface 79a of the third seal member 793 has a curved surface (R). For this reason, even when the small diameter portion 79c6 opens in the end surface 79a, the degree of adhesion between the small diameter portion 79c6 and the outer periphery of the main body portion 75a1 and between the end surface 79a and the flange portion 75c (surface 754) is improved. The small diameter portion 79c6 and the end surface 79a of the third seal member 793 function as a so-called continuous (unbroken) seal surface. Therefore, the sealing performance of the third seal member 793 is improved. Other functions and effects are the same as those of the first embodiment.

[Eighth embodiment]
First, the configuration will be described with reference to FIGS. FIG. 24 is an exploded perspective view similar to FIG. 6, including the third seal member 793 of the present embodiment. The illustration of the first spring 781 is omitted. The third seal member 793 is integrated with the valve case 76 as one part 794. The component 794 is made of, for example, a polyamide-based resin. Therefore, the number of parts can be reduced and the assembling property can be improved. Other configurations and operational effects are the same as those of the first embodiment. The seal body of the third seal member 793 of the second, third, fifth, and seventh embodiments and the third seal member 793 of the fourth embodiment may be integrated with the valve case 76. Further, the third seal member 793 of the sixth embodiment may be integrated with the valve case 76, and the main body 75a1 of the piston 75 may be the one of the sixth embodiment.

[Other Embodiments]
As mentioned above, although the form for implementing this invention was demonstrated based on drawing, the specific structure of this invention is not limited to embodiment, The design change etc. of the range which does not deviate from the summary of invention are included. Even if it exists, it is included in this invention. For example, the specific structures of the first unit 1A and the second unit 1B are not limited to those in the embodiment. The pump 7 may be a plunger pump provided with a seal member that separates the inside of the cylinder in the direction of the movement axis of the piston, and its specific configuration is not limited to that of this embodiment. The number of pistons (pump parts) is arbitrary. The member that drives the piston is not limited to the eccentric cam, and may be a swash plate or the like. The arrangement form of the pistons is not limited to the radial type, but may be an axial type. The cylinder is not limited to a fixed one (fixed cylinder type), and may rotate with the piston (rotary cylinder type). In the embodiment, the outer periphery of the third seal member 793 has a cylindrical shape that can come into full contact with the inner periphery of the cylinder 71. The shape may be in contact with The shape of the third seal member 793 facing the pressure chamber (third space 123) on the other side in the axial direction may be a concave shape such as V packing or U packing. In the embodiment, the third seal member 793 is a piston seal that is attached to the piston 75 and slides against the inner periphery of the cylinder 71, but is a rod seal that is attached to the cylinder 71 and the outer periphery of the piston 75 slides relative thereto. There may be. In this case, if the outer periphery of the third seal member 793 is in partial contact with the inner periphery of the cylinder 71, the radial position of the piston 75 relative to the cylinder 71 is regulated via the third seal member 793. At the same time, the frictional force of the piston 75 against the cylinder 71 (including the third seal member 793) decreases. The point is that the seal member may be configured to partially contact the surface in a range where the seal member is opposed to the surface of the member to which the seal member is mounted in the radial direction.

[Technical ideas that can be grasped from the embodiment]
The technical idea (or technical solution, the same applies hereinafter) that can be understood from the embodiment described above will be described below.
(1) The brake device of the present technical idea is, in one aspect thereof,
A housing having a liquid passage and a hole therein;
A cylinder housed in the hole, a piston housed in the cylinder so as to be movable, and the inside of the cylinder is separated in a direction of a movement axis of the piston, and an inner circumference is a part of an outer circumference of the piston A plunger pump connected to the liquid path,
Is provided.
(2) In a more preferred embodiment, in the above embodiment,
The inner periphery of the seal member partially contacts the outer periphery of the piston in the circumferential direction of the piston.
(3) In another preferred embodiment, in any of the above embodiments,
The seal member has, on its inner periphery, a seal member side contact portion that is a portion that contacts the outer periphery of the piston regardless of the position of the piston in the circumferential direction with respect to the piston.
(4) In still another preferred embodiment, in any of the above embodiments,
The seal member side contact portion is on each side of the polygon as viewed from the moving axis direction of the piston.
(5) In still another preferred embodiment, in any of the above embodiments,
The polygon is a hexagon.
(6) In still another preferred embodiment, in any of the above embodiments,
The polygon is a pentagon.
(7) In still another preferred embodiment, in any of the above embodiments,
The seal member has a hole between an outer peripheral surface thereof and the seal member side contact portion.
(8) In still another preferred embodiment, in any of the above embodiments,
The seal member side contact portion is a protrusion protruding inward in the radial direction of the seal member.
(9) In still another preferred embodiment, in any of the above embodiments,
The piston has a piston side contact portion on the outer periphery thereof, which is a portion that contacts the inner periphery of the seal member regardless of the position of the piston in the circumferential direction with respect to the seal member. (10) In still another preferred embodiment, in any of the above embodiments,
The piston-side contact portion includes each vertex of a polygon as viewed from the moving axis direction of the piston.
(11) In still another preferred embodiment, in any of the above embodiments,
The seal member includes a main body portion that contacts the inner periphery of the cylinder, and an interposition member that contacts the inner periphery of the main body portion and the outer periphery of the piston.
(12) In still another preferred embodiment, in any of the above embodiments,
The inner periphery of the seal member partially contacts the outer periphery of the piston in the direction of the movement axis of the piston.
(13) In another aspect, the brake device of the present technical idea,
A housing having a liquid passage and a hole formed therein;
A cylinder housed in the hole, a piston housed in the cylinder so as to be movable, and the inside of the cylinder is separated in a direction of a movement axis of the piston, and an inner circumference is a part of an outer circumference of the piston A plunger pump having a sealing member that comes into contact with each other, and capable of discharging brake fluid into the fluid path;
A cam mechanism for moving the piston in contact with an end surface on one side in the movement axis direction of the piston;
A rotary drive shaft provided on the outer periphery with the cam mechanism;
An electric motor for rotating the rotary drive shaft;
Is provided.
(14) In a more preferred embodiment, in the above embodiment,
The inner periphery of the seal member is polygonal when viewed from the moving axis direction of the piston.
(15) From another viewpoint, the plunger pump of the present technical idea is
A cylinder,
A piston movably accommodated within the cylinder;
A seal member that divides the inside of the cylinder in the direction of the movement axis of the piston, and the inner periphery partially contacts the outer periphery of the piston;
Is provided.
(16) In a more preferred embodiment, in the above embodiment,
The inner periphery of the seal member partially contacts the outer periphery of the piston in the circumferential direction of the piston.
(17) In still another preferred embodiment, in any of the above embodiments,
The seal member has, on its inner periphery, a seal member side contact portion that is a portion that contacts the outer periphery of the piston regardless of the position of the seal member with respect to the piston in the circumferential direction of the piston.
(18) In still another preferred embodiment, in any of the above embodiments,
The seal member side contact portion is on each side of the polygon as viewed from the moving axis direction of the piston.
(19) In still another preferred embodiment, in any of the above embodiments,
The seal member side contact portion is a protrusion protruding inward in the radial direction of the seal member.
(20) In still another preferred embodiment, in any of the above embodiments,
The piston has, on its outer periphery, a piston-side contact portion that is a portion that contacts the inner periphery of the seal member regardless of the position of the piston in the circumferential direction with respect to the seal member.

Although only a few embodiments of the present invention have been described above, various modifications or improvements can be made to the illustrated embodiments without substantially departing from the novel teachings and advantages of the present invention. Will be easily understood by those skilled in the art. Therefore, it is intended that the embodiment added with such changes or improvements is also included in the technical scope of the present invention. You may combine the said embodiment arbitrarily.

This application claims priority based on Japanese Patent Application No. 2016-081087 filed on Apr. 14, 2016. The entire disclosure including the specification, claims, drawings, and abstract of Japanese Patent Application No. 2016-081087 filed on April 14, 2016 is incorporated herein by reference in its entirety.

1B Second unit (brake device) 13 Discharge liquid path 6 Housing 62 Cylinder housing hole 7 Plunger pump 7a Electric motor 70 Cam mechanism 700 Rotation drive shaft 71 Cylinder 75 Piston 793 Third seal member

Claims

A brake device, the brake device comprising:
A housing having a liquid passage and a hole therein;
A plunger pump connected to the liquid path, the plunger pump comprising:
A cylinder housed in the hole;
A piston movably accommodated within the cylinder;
A brake device comprising: the seal member that divides the inside of the cylinder in a direction of a movement axis of the piston, and the inner periphery of the seal member partially contacts the outer periphery of the piston.
The brake device according to claim 1, wherein
The brake device, wherein an inner periphery of the seal member partially contacts an outer periphery of the piston in a circumferential direction of the piston.
The brake device according to claim 2,
The said sealing member is a brake device which has a sealing member side contact part which is a part which contacts with respect to the outer periphery of the said piston irrespective of the position with respect to the said piston in the circumferential direction of the said piston at the inner periphery of this sealing member.
The brake device according to claim 3,
The said sealing member side contact part is a brake device which exists in each polygonal side seeing from the moving-axis direction of the said piston.
The brake device according to claim 4,
The brake device, wherein the polygon is a hexagon.
The brake device according to claim 4,
The brake device, wherein the polygon is a pentagon.
The brake device according to claim 4,
The said sealing member is a brake device which has a hole between the outer peripheral surface of this sealing member, and the said sealing member side contact part.
The brake device according to claim 3,
The seal member-side contact portion is a brake device that is a protrusion protruding radially inward of the seal member.
The brake device according to claim 2,
The said piston has a piston side contact part which is a part which contacts with respect to the inner periphery of the said sealing member regardless of the position with respect to the said sealing member in the circumferential direction of the said piston on the outer periphery of this piston.
The brake device according to claim 9,
The said piston side contact part is a brake device containing each vertex of a polygon seeing from the moving-axis direction of the said piston.
The brake device according to claim 1, wherein
The said sealing member is a brake device which has a main-body part which contacts with respect to the inner periphery of the said cylinder, and the interposition member which contacts with respect to the inner periphery of the said main-body part, and the outer periphery of the said piston.
The brake device according to claim 1, wherein
The brake device, wherein an inner periphery of the seal member is partially in contact with an outer periphery of the piston in a moving axis direction of the piston.
A brake device, the brake device comprising:
A housing having a liquid passage and a hole formed therein;
A plunger pump capable of discharging brake fluid into the fluid path;
The plunger pump
A cylinder housed in the hole;
A piston movably accommodated within the cylinder;
The inside of the cylinder is separated in the direction of the movement axis of the piston, and the seal member has an inner periphery partly in contact with the outer periphery of the piston,
The brake device is further in contact with an end surface on one side in the movement axis direction of the piston, and a cam mechanism for moving the piston;
A rotary drive shaft provided on the outer periphery with the cam mechanism;
An electric motor for rotating the rotary drive shaft;
A brake device comprising:
The brake device according to claim 13,
The brake device according to claim 1, wherein an inner periphery of the seal member is polygonal when viewed from a moving axis direction of the piston.
A plunger pump, the plunger pump comprising:
A cylinder,
A piston movably accommodated within the cylinder;
The seal member that divides the inside of the cylinder in the direction of the movement axis of the piston, and the inner periphery of the seal member partially contacts the outer periphery of the piston;
A plunger pump comprising:
The plunger pump according to claim 15,
The plunger pump, wherein an inner periphery of the seal member is partially in contact with an outer periphery of the piston in a circumferential direction of the piston.
The plunger pump according to claim 16,
The said seal member is a plunger pump which has a seal member side contact part which is a part which contacts with respect to the outer periphery of the said piston irrespective of the position with respect to the said piston in the circumferential direction of the said piston at the inner periphery of this seal member.
The plunger pump according to claim 17,
The said seal member side contact part is a plunger pump which exists in each polygonal side seeing from the moving-axis direction of the said piston.
The plunger pump according to claim 17,
The seal member-side contact portion is a plunger pump that is a protrusion that protrudes radially inward of the seal member.
The plunger pump according to claim 16,
The said piston has a piston side contact part which is a part which contacts with respect to the inner periphery of the said sealing member regardless of the position with respect to the said sealing member in the circumferential direction of the said piston on the outer periphery of this piston.