Pump device

Abstract

The present invention attenuates the noise caused by pulsation of brake fluid generated when driving the pump. The pulsation attenuation portion (80) provided in the pump device has a fixed member (86) that divides the housing chamber (58) into an upstream side region and a downstream side region, the fixed member (86) having a fixed member hole (86b). The upstream side region has an upstream side movable member (84), an inflow opening side damping portion (81a) that houses an inflow opening side elastomer (92), and a fixed member side damping portion (81b) that houses a fixed member side elastomer (91). The downstream side region has an outflow opening side damping portion (81c) that houses an outflow opening side elastomer (90), and a downstream side movable member (85) that has a downstream side hole (85c). The fixed member (86) has a cylindrical portion (86d) that extends toward the cover portion (82) and is capable of abutting against the valve member (94), and the upstream side movable member (84) has a through hole (84b) having a seat portion (84d) that is capable of being closed by the valve member (94).

Description

TECHNICAL FIELD

[0001] The present application relates to a pump device equipped in a hydraulic circuit of a brake. BACKGROUND

[0002] As a brake system for a vehicle in the related art, there is a brake system provided with a hydraulic circuit having a main flow path that communicates a master cylinder and a wheel cylinder, a sub flow path that discharges brake fluid of the main flow path, and a supply flow path that supplies brake fluid to a middle portion of the sub flow path.

[0003] For example, an upstream side end portion of a flow of brake fluid of the sub flow path is connected to a region of the main flow path on the wheel cylinder side with reference to an inlet valve, and a downstream side end portion of the sub flow path is connected to a region of the main flow path on the master cylinder side with reference to an outlet valve. Further, an upstream side end portion of a flow of brake fluid of the supply flow path is communicated to the master cylinder, and a downstream side end portion of the supply flow path is connected to a region on a downstream side of the sub flow path with reference to the outlet valve and to a suction side of a pump provided in the region. Further, a first switching valve is provided in a region of the main flow path on the master cylinder side with reference to a connection portion connected to the downstream side end portion of the sub flow path, and a second switching valve is provided in the middle portion of the supply flow path.

[0004] For example, the hydraulic control unit is configured by the inlet valve, the outlet valve, the pump, the first switching valve, the second switching valve, a base body in which these devices are housed, and a controller that manages the operation of these devices. In the hydraulic control unit, the hydraulic pressure of the hydraulic circuit is controlled by controlling the operation of the inlet valve, the outlet valve, the pump, the first switching valve, and the second switching valve.

[0005] In particular, when the need to raise the hydraulic pressure of brake fluid of the wheel cylinder arises regardless of the state of brake operation of an input portion (for example, a brake pedal or the like) of the brake system, the pump is driven in a state in which the inlet valve is open, the outlet valve is closed, the first switching valve is closed, and the second switching valve is open.

[0006] When the pump is driven, pulsation generated at the brake fluid is transmitted from the brake system to an engine room of the vehicle and noise is generated. The noise is sometimes of a size that is uncomfortable for a user (driver). Therefore, for the hydraulic control unit of the brake system in the related art, a scheme for attenuating the pulsation generated when the pump is driven has also been proposed. For example, the hydraulic control unit of the brake system described in Patent Document 1 is provided with one pump in one hydraulic circuit, and is provided with a pulsation attenuation portion that attenuates the pulsation of brake fluid discharged from the pump on the discharge side of the pump.

[0007] Patent Document 1: Japanese Patent Application Publication No. 2017-061246.

[0008] PROBLEMS TO BE SOLVED BY THE INVENTION

[0009] In recent brake systems, there are cases where a force multiplier is miniaturized or omitted in order to improve mountability of the brake system to a vehicle. In such brake systems, the hydraulic pressure of brake fluid of a wheel cylinder is mostly insufficient, so the number of times of driving of a pump increases. That is, in such brake systems, noise caused by pulsation generated at the time of driving of the pump becomes more likely to occur. Therefore, in recent years, further attenuation of the pulsation generated at the time of driving of the pump is required.

[0010] As a structure for achieving further attenuation of the pulsation generated at the time of driving of the pump, according to the structure of the hydraulic pressure control unit of the brake system described in Patent Document 1, a hydraulic brake device having a pulsation damper in which a plurality of metal films are overlapped is proposed. However, when the configuration in which a plurality of the same metal films are overlapped, there is a limit in terms of coping with the pulsation caused by the characteristics of the hydraulic pressure control unit based on the output and the rotational speed of the pump motor. SUMMARY

[0011] The present application is made in the light of the above-described problems, and provides a brake system capable of attenuating noise caused by pulsation generated at the time of driving of a pump.

[0012] Means for solving the problem

[0013] The pump device of the present application is provided in a base, and has a pulsation damping portion that damps pulsation of brake fluid discharged from a pump, wherein the pulsation damping portion includes a housing chamber, a fixed member, an upstream movable member, an inflow opening side damping portion, a fixed member side damping portion, a downstream movable member, an outflow opening side damping portion, a fixed member hole, a downstream hole, an inflow opening side elastic body, a fixed member side elastic body, and an outflow opening side elastic body, the housing chamber is provided in the base, the housing chamber is cylindrical, the fixed member divides the housing chamber into an upstream region and a downstream region, the upstream movable member is provided in the upstream region and is slidable in the axial direction, the inflow opening side damping portion is provided in the upstream region, communicates with an inflow opening through which the brake fluid flows, and is formed between the upstream movable member and a cover portion of the housing chamber, the fixed member side damping portion is provided in the upstream region, is formed between the upstream movable member and the fixed member, the downstream movable member is provided in the downstream region and is slidable in the axial direction, the outflow opening side damping portion is provided in the downstream region, communicates with an outflow opening through which the brake fluid flows, and is formed between the downstream movable member and a bottom portion of the housing chamber, the fixed member hole is formed in the fixed member, the downstream hole is formed in the downstream movable member, the inflow opening side elastic body is provided in the inflow opening side damping portion, applies a force to the upstream movable member toward the fixed member side, the fixed member side elastic body is provided in the fixed member side damping portion, applies a force to the upstream movable member toward the cover portion side, and the outflow opening side elastic body is provided in the outflow opening side damping portion, applies a force to the downstream movable member toward the fixed member side, the fixed member has a cylindrical portion that extends toward the cover portion side, the upstream movable member has a through hole having a seat portion configured to be closed by seating of a valve member that is pushed from the cover portion side, in a process in which the upstream movable member moves toward the fixed member side due to pressure of the brake fluid that flows into the inflow opening side damping portion, the valve member comes into abutment with the cylindrical portion to disengage from the seat portion, whereby the brake fluid flows into the through hole, the pressure of the fixed member side damping portion rises, the downstream movable member that is in abutment with the fixed member moves toward the bottom portion side due to the rise in the pressure of the fixed member side damping portion, and the brake fluid flows out from the outflow opening through the fixed member hole and the downstream hole.

[0014] Effect of the Invention

[0015] In the brake system, noise caused by pulsation of brake fluid generated when a pump is driven can be reduced. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1is a diagram showing an example of a system configuration of a brake system of an embodiment of the present application.

[0017] Figure 2 is a partial cross-sectional view showing an example of a mounting state of a pump and a damper unit of a hydraulic control unit of a brake system of an embodiment of the present application to a base.

[0018] Figure 3 is an enlarged cross-sectional view of a pulsation damping portion in a state where a pump is not driven in an embodiment of the present application.

[0019] Figure 4 is an enlarged cross-sectional view of a pulsation damping portion in a state where a movable member on an upstream side is moving halfway after a pump is driven in an embodiment of the present application.

[0020] Figure 5 is an enlarged cross-sectional view of a pulsation damping portion in a state where brake fluid is flowing out from an outflow opening after a pump is driven in an embodiment of the present application. DETAILED DESCRIPTION

[0021] Hereinafter, a hydraulic control unit of the present application will be described with reference to the drawings. Note that hereinafter, a case where a brake system including the hydraulic control unit of the present application is mounted on a four-wheeled vehicle will be described, but the brake system including the hydraulic control unit of the present application can be mounted on other vehicles (two-wheeled vehicles, trucks, buses, and the like) other than four-wheeled vehicles. Furthermore, the structure, operation, and the like described below are examples, and the brake system including the hydraulic control unit of the present application is not limited to the structure, operation, and the like. Furthermore, in each drawing, the same reference signs or no reference signs are attached to the same or similar components or portions. Furthermore, regarding detailed structures, illustration is appropriately simplified or omitted.

[0022] <Structure and operation of brake system 1>

[0023] The structure and operation of the brake system 1 of the present embodiment will be described. Figure 1 is a diagram showing an example of a system configuration of a brake system of an embodiment of the present application.

[0024] As shown in Figure 1 , the brake system 1 is mounted on a vehicle 100, and includes a hydraulic circuit 2 having a main flow path 13 that communicates a master cylinder 11 and a wheel cylinder 12, a sub flow path 14 that discharges brake fluid of the main flow path 13, and a supply flow path 15 that supplies brake fluid to the sub flow path 14. The hydraulic circuit 2 is filled with brake fluid.

[0025] Further, the brake system 1 of the present embodiment has two hydraulic circuits 2a, 2b. The hydraulic circuit 2a is a hydraulic circuit in which the master cylinder 11 and the wheel cylinders 12 of the wheels RL, FR are communicated by the main flow path 13. The hydraulic circuit 2b is a hydraulic circuit in which the master cylinder 11 and the wheel cylinders 12 of the wheels FL, RR are communicated by the main flow path 13. These hydraulic circuits 2a, 2b are the same structure except for the communicated wheel cylinders 12.

[0026] A piston (not shown) that reciprocates in conjunction with a brake pedal 16 that is an example of an input portion of the brake system 1 is built in the master cylinder 11. A force multiplying device 17 is located between the brake pedal 16 and the piston of the master cylinder 11, and the user's stepping force is amplified and transmitted to the piston. The wheel cylinders 12 are provided to brake calipers 18. When the hydraulic pressure of the brake fluid of the wheel cylinders 12 is increased, the brake pads 19 of the brake calipers 18 are pushed against the rotors 20, and the wheels are braked.

[0027] The upstream side end portion of the sub flow path 14 is connected to the first intermediate portion 13a of the main flow path 13, and the downstream side end portion of the sub flow path 14 is connected to the second intermediate portion 13b of the main flow path 13 that is upstream of the first intermediate portion 13a. Further, the upstream side end portion of the supply flow path 15 is communicated with the master cylinder 11, and the downstream side end portion of the supply flow path 15 is connected to the third intermediate portion 14a of the sub flow path 14.

[0028] An inlet valve (EV) 31 is provided in the region between the second intermediate portion 13b and the first intermediate portion 13a in the main flow path 13. An outlet valve (AV) 32 is provided in the region between the first intermediate portion 13a and the third intermediate portion 14a in the sub flow path 14. A reservoir 33 is provided in the region between the outlet valve 32 and the third intermediate portion 14a in the sub flow path 14. The inlet valve 31 is, for example, an electromagnetic valve that is open in a non-energized state and closed in an energized state. The outlet valve 32 is, for example, an electromagnetic valve that is closed in a non-energized state and open in an energized state.

[0029] Further, a pump 60 is provided in the region between the third intermediate portion 14a and the second intermediate portion 13b in the sub flow path 14. The suction side of the pump 60 is communicated with the third intermediate portion 14a. The discharge side of the pump 60 is communicated with the second intermediate portion 13b of the main flow path 13. A pulsation damping portion 80 is provided in the region between the discharge side of the pump 60 and the second intermediate portion 13b that is a part of the sub flow path 14.

[0030] The pulsation damping portion 80 attenuates the pulsation of the brake fluid discharged from the pump 60. In detail, the discharge side of the pump 60 is connected to an inflow opening 95b (refer to Figure 2 ) of the pulsation damping portion 80 into which the brake fluid flows, and an outflow opening 95c (refer to Figure 2) is connected to the second intermediate portion 13b of the main flow passage 13. In the following description, the flow passage between the discharge side of the pump 60 and the inflow opening 95b is referred to as a first discharge flow passage 140a, and the flow passage between the outflow opening 95c and the second intermediate portion 13b of the main flow passage 13 is referred to as a second discharge flow passage 140b.

[0031] The first switching valve (USV) 35 is provided in a region of the main flow passage 13 on the master cylinder 11 side with the second intermediate portion 13b as a reference. The second switching valve (HSV) 36, the damping unit 37 are provided on the supply flow passage 15. The damping unit 37 is provided in a region of the supply flow passage 15 between the second switching valve 36 and the third intermediate portion 14a of the sub flow passage 14. The first switching valve 35 is, for example, an electromagnetic valve that is open in a non-energized state and closed in an energized state. The second switching valve 36 is, for example, an electromagnetic valve that is closed in a non-energized state and open in an energized state.

[0032] The inlet valve 31, the outlet valve 32, the reservoir 33, the pump 60, the first switching valve 35, the second switching valve 36, the damping unit 37, and the pulsation damping portion 80 are provided to a base 51 that is internally formed with flow passages for constituting the main flow passage 13, the sub flow passage 14, and the supply flow passage 15. The components (the inlet valve 31, the outlet valve 32, the reservoir 33, the pump 60, the first switching valve 35, the second switching valve 36, the damping unit 37, and the pulsation damping portion 80) can be provided in a concentrated manner to one base 51, or can be provided separately to a plurality of bases 51.

[0033] The hydraulic control unit 50 is constituted at least by the base 51, the components provided to the base 51, and the controller (ECU) 52. In the hydraulic control unit 50, the actions of the inlet valve 31, the outlet valve 32, the pump 60, the first switching valve 35, and the second switching valve 36 are controlled by the controller 52, whereby the hydraulic pressure of the brake fluid of the wheel cylinder 12 is controlled. That is, the controller 52 manages the actions of the inlet valve 31, the outlet valve 32, the pump 60, the first switching valve 35, and the second switching valve 36.

[0034] The controller 52 can be one, or can be divided into a plurality. Further, the controller 52 can be mounted to the base 51, or can be mounted to other components. Further, a part or all of the controller 52 can be constituted by, for example, a personal computer, a microprocessor unit, or the like, or can be constituted by a component that can be updated such as firmware, or can be a program module or the like that is executed in accordance with an instruction from a CPU or the like.

[0035] The controller 52 implements the following hydraulic control operation in addition to the well-known hydraulic control operation (ABS control operation, ESP control operation, etc.). When the inlet valve 31 is open, the outlet valve 32 is closed, the first switching valve 35 is open, and the second switching valve 36 is closed, if a deficiency or a possibility of deficiency in the hydraulic pressure of the hydraulic circuit 2 is detected from the detection signal of the position sensor of the brake pedal 16 and the detection signal of the hydraulic pressure sensor of the hydraulic circuit 2 when the brake pedal 16 of the vehicle 100 is operated, the controller 52 starts a positive pressure control operation.

[0036] In the positive pressure control operation, the controller 52 makes the flow of brake fluid from the second intermediate portion 13b of the main flow passage 13 to the wheel cylinder 12 possible by making the inlet valve 31 in an open state. Further, the controller 52 restricts the flow of brake fluid from the wheel cylinder 12 to the reservoir 33 by making the outlet valve 32 in a closed state. Further, the controller 52 restricts the flow of brake fluid from the master cylinder 11 to the second intermediate portion 13b of the main flow passage 13 without passing through the pump 60 by closing the first switching valve 35. Further, the controller 52 makes the flow of brake fluid from the master cylinder 11 to the second intermediate portion 13b of the main flow passage 13 possible via the pump 60 by opening the second switching valve 36. Further, the controller 52 makes the hydraulic pressure of the brake fluid of the wheel cylinder 12 rise (increase) by driving the pump 60.

[0037] If the resolution or avoidance of the deficiency in the hydraulic pressure of the hydraulic circuit 2 is detected, the controller 52 opens the first switching valve 35, closes the second switching valve 36, and stops the driving of the pump 60, whereby the positive pressure control operation is ended.

[0038] Here, if the pump 60 is driven, there is a case where the pulsation generated in the brake fluid is transmitted to the wheel cylinder 12 through the sub flow passage 14 and the main flow passage 13. Also, there is a case where the pulsation is also transmitted to the engine room in which the hydraulic control unit 50 of the brake system 1 is accommodated to generate noise. The noise sometimes becomes a size that the user (driver) feels uncomfortable. Therefore, it is important to achieve the attenuation of the pulsation generated when the pump 60 is driven.

[0039] Thus, in the brake system 1, that is, the hydraulic control unit 50 of the present embodiment, the brake fluid discharged from the pump 60 flows into the pulsation attenuation portion 80. Also, the brake fluid that has flowed into the pulsation attenuation portion 80 is attenuated in pulsation in the pulsation attenuation portion 80 and then flows to the downstream side from the pulsation attenuation portion 80. Therefore, the brake system 1, that is, the hydraulic control unit 50 of the present embodiment can attenuate the pulsation generated when the pump 60 is driven.

[0040] Further, in the above-mentioned active supercharging control, the pump 60 is driven in a state where the user operates (steps on) the brake pedal 16 and the second switching valve 36 is open. Therefore, pulsation generated in the brake fluid propagates to the brake pedal 16 via the supply flow path 15 and the master cylinder 11, which can cause the user to feel uncomfortable. Therefore, the brake system 1, i.e., the hydraulic control unit 50 of the present embodiment preferably has the damping unit 37 as shown in Figure 1 Because, by means of the damping unit 37, pulsation of the brake fluid propagating from the pump 60 to the brake pedal 16 can be attenuated.

[0041] Further, in the case where the damping unit 37 is provided in the brake system 1 omitting the force multiplication device 17, the damping unit 37 can be provided in a region between the upstream side end portion of the supply flow path 15 and the second switching valve 36. By providing the damping unit 37 in such a position, when the user steps on the brake pedal 16, the brake fluid can flow into the damping unit 37, and the reaction force of the brake fluid in the hydraulic circuit 2 toward the brake pedal 16 is reduced. Therefore, when the user steps on the brake pedal, the same stepping amount of the brake pedal 16 as in the brake system 1 having the force multiplication device 17 is obtained. Therefore, the user can obtain the same feeling of use as in the brake system 1 having the force multiplication device 17 in the brake system 1 omitting the force multiplication device 17.

[0042] <Mounting structure of pump 60 and pulsation attenuating portion 80 to base 51>

[0043] An example of the structure when the pump 60 and the pulsation attenuating portion 80 are mounted to the base 51 in the hydraulic control unit 50 of the brake system 1 of the present embodiment will be described. Figure 2 is a partial cross-sectional view showing an example of the mounting state of the pump 60 and the pulsation attenuating portion 80 to the base in the hydraulic control unit of the brake system of the present embodiment. Figure 2 shows a state where the drive shaft 57 of the piston 62 of the drive pump 60 is dismounted. Therefore, Figure 2 In

[0044] As shown in Figure 2 , a drive shaft housing chamber 59 in which the drive shaft 57 of the piston 62 of the drive pump 60 is provided is formed in the base 51. The drive shaft housing chamber 59 is a bottomed hole formed in the outer wall of the base 51. Further, a pump housing chamber 53 in which the pump 60 is housed is formed in the base 51. The pump housing chamber 53 is a cylindrical stepped hole which penetrates the outer wall of the base 51 toward the drive shaft housing chamber 59.

[0045] The pump 60 housed in the pump housing chamber 53 is provided with a pressure cylinder 61 and a piston 62. The pressure cylinder 61 is formed in a cylindrical shape having a pressure cylinder bottom portion 61b. The piston 62 is housed in the pressure cylinder 61 on one end side thereof. Further, a space surrounded by the inner peripheral surface of the pressure cylinder 61 and the one end of the piston 62 is a pump chamber 63. The piston 62 is freely reciprocated in the axial direction of the pressure cylinder 61. Furthermore, an end portion 62a on the other end side of the piston 62 protrudes into the drive shaft housing chamber 59. Furthermore, an annular pressure cylinder side sealing member 66 is attached to the portion of the piston 62 housed in the pressure cylinder 61. With the pressure cylinder side sealing member 66, the brake fluid is prevented from leaking between the outer peripheral surface of the piston 62 and the inner peripheral surface of the pressure cylinder 61.

[0046] Further, in the pressure cylinder 61, a piston spring 67 is housed between the pressure cylinder bottom portion 61b and the piston 62, that is, in the pump chamber 63. With the piston spring 67, the piston 62 is always urged toward the drive shaft housing chamber 59 side. Thus, the end portion 62a of the piston 62 abuts against the eccentric portion 57a of the drive shaft 57 formed in the drive shaft housing chamber 59. The center position of the eccentric portion 57a is eccentric with respect to the center of rotation of the drive shaft 57. Therefore, if the drive shaft 57 is rotated by a drive source not shown, the eccentric portion 57a eccentrically rotates with respect to the center of rotation of the drive shaft 57. That is, by the eccentric rotation of the eccentric portion 57a, the piston 62 whose end portion 62a abuts against the eccentric portion 57a reciprocates in the axial direction of the pressure cylinder 61.

[0047] The portion of the piston 62 protruding from the pressure cylinder 61 is slidably guided by a piston guide member 68 provided to the inner peripheral surface of the pump housing chamber 53. Further, an annular drive shaft side sealing member 69 is attached to the pump housing chamber 53 in abutment with the piston guide member 68. With the drive shaft side sealing member 69, the brake fluid is prevented from leaking from the outer peripheral surface of the piston 62 toward the drive shaft housing chamber 59 side.

[0048] In the piston 62, a bottomed hole 62b is formed which opens to the pump chamber 63 side of the pressure cylinder 61 in the axial direction. In the piston 62, a suction port 62c is also formed which communicates the outer peripheral surface and the bottomed hole 62b. Further, a suction valve not shown which freely blocks and unblocks the opening of the bottomed hole 62b is provided to the piston 62. The suction valve is provided with a suction valve member which is a ball valve that blocks the opening of the bottomed hole 62b, and a suction valve spring which urges the suction valve member from the pressure cylinder 61 side. Further, on the end portion of the pressure cylinder 61 on the piston 62 side, a cylindrical filter 70 is attached in a manner to cover the opening of the suction port 62c of the piston 62.

[0049] A communication hole 61c that communicates the pump chamber 63 and the outside of the pressure cylinder 61 is formed in the bottom portion 61b of the pressure cylinder 61. An opening portion side discharge valve 64 is provided on the opening portion side of the communication hole 61c on the side opposite the pump chamber 63. The opening portion side discharge valve 64 has an opening portion side valve member 64a that is a ball valve, an opening portion side valve seat 64b formed in the opening end of the communication hole 61c, and an opening portion side spring 64c that exerts a force on the opening portion side valve member 64a in a direction that causes the opening portion side valve member 64a to seat against the opening portion side valve seat 64b. The opening portion side discharge valve 64 is disposed between the pressure cylinder 61 and a cover 65.

[0050] In detail, the cover 65 is attached to the pressure cylinder bottom portion 61b, for example, by press fitting. A bottomed hole 65a is formed in the cover 65, and the bottomed hole 65a has an opening portion at a position facing the communication hole 61c of the pressure cylinder bottom portion 61b. Further, the opening portion side spring 64c of the opening portion side discharge valve 64 is housed in the bottomed hole 65a. In addition, the inner diameter of the bottomed hole 65a is larger than the outer diameter of the opening portion side valve member 64a. Therefore, when the opening portion side valve member 64a is disengaged from the opening portion side valve seat 64b, the opening portion side valve member 64a moves into the bottomed hole 65a. That is, when the hydraulic pressure of the brake fluid in the pump chamber 63 of the pressure cylinder 61 rises and the force with which the brake fluid pushes against the opening portion side valve member 64a becomes greater than the force of the opening portion side spring 64c, the opening portion side valve member 64a is disengaged from the opening portion side valve seat 64b, and the pump chamber 63 and the bottomed hole 65a of the cover 65 communicate via the communication hole 61c. Further, the brake fluid in the pump chamber 63 flows into the bottomed hole 65a. In the cover 65, a drain hole 65b is formed as a passage that communicates the outside of the cover 65 and the bottomed hole 65a. The brake fluid that has flowed into the bottomed hole 65a of the cover 65 passes through the drain hole 65b and is discharged to the outside of the pump 60 from a discharge chamber 54 described later.

[0051] The pump 60 thus configured is housed in the pump housing chamber 53 formed in the base 51 as described above. Specifically, the pump 60 is press fitted to a position where the annular protrusion 61a formed in the outer peripheral portion of the pressure cylinder 61 abuts against the stepped portion 53a of the pump housing chamber 53, and is thereby fixed in the pump housing chamber 53 of the base 51.

[0052] When the pump 60 is thus housed in the pump housing chamber 53, a space, i.e., a discharge chamber 54, that communicates with the drain hole 65b of the pump 60 is formed between the outer peripheral surface of the pump 60 and the inner peripheral surface of the pump housing chamber 53. The discharge chamber 54 is a space that is annularly formed on the outer peripheral side of the pump 60 in a manner that communicates with the drain hole 65b of the pump 60. The discharge chamber 54 is connected to the first discharge passage 140a as described later.

[0053] Further, at the pump 60, the space between the annular protrusion 61a of the pressure cylinder 61 and the cover 65 is partitioned into two spaces by the partition 71. Also, the space on the cover 65 side than the partition 71 becomes the discharge chamber 54. In the present embodiment, an O-ring (not shown) is provided in the annular groove formed in the partition 71.

[0054] Further, in the present embodiment, when the pump 60 is housed in the pump housing chamber 53, a space, i.e., the annular flow path 56, which communicates with the suction port 62c of the pump 60 is formed between the outer peripheral surface of the pump 60 and the inner peripheral surface of the pump housing chamber 53. That is, the annular flow path 56 is a space formed annularly on the outer peripheral side of the pump 60 in a manner to communicate with the suction port 62c of the pump 60. The annular flow path 56 is formed between the annular protrusion 61a of the pressure cylinder 61 and the drive shaft side sealing member 69. In other words, the annular flow path 56 is formed on the outer peripheral side of the filter 70 provided in a manner to cover the opening of the suction port 62c.

[0055] The annular flow path 56 communicates with the 3rd intermediate portion 14a of the sub flow path 14 in the hydraulic control unit 50 by means of an internal flow path, not shown, formed in the base 51. Figure 1 In other words, the annular flow path 56 constitutes a part of the sub flow path 14. When the pump 60 is housed in the pump housing chamber 53, the suction port 62c of the pump 60 and the 3rd intermediate portion 14a need to communicate. Since the annular flow path 56 is provided, when the pump 60 is housed in the pump housing chamber 53, no alignment for communicating the suction port 62c of the pump 60 and the 3rd intermediate portion 14a is required. Therefore, since the annular flow path 56 is provided, the assembly of the hydraulic control unit 50 becomes easy. Further, since the annular flow path 56 is provided, when the pump housing chamber 53 is machined in the base 51, a part of the sub flow path 14 is also machined. Therefore, it is also possible to reduce the machining cost of the base 51, i.e., the manufacturing cost of the hydraulic control unit 50. Further, since the annular flow path 56 is provided, it is possible to effectively utilize the space on the outer peripheral side of the pump 60 as the sub flow path 14, so it is also possible to downsize the base 51, i.e., the hydraulic control unit 50.

[0056] The housing chamber 58 is a housing chamber which houses the pulsation damping portion 80, and is a bottomed hole formed in the outer wall of the base 51. As described above, the discharge chamber 54 formed on the outer peripheral surface side of the pump 60 is connected to the 1st discharge flow path 140a which constitutes a part of the discharge flow path 140. The discharge chamber 54 is connected to the inflow opening 95b of the pulsation damping portion 80 via the 1st discharge flow path 140a. Figure 2 In the present embodiment, the housing chamber 58 is configured such that the brake fluid flows in from the lateral direction with respect to the axis of the pulsation damping portion 80. Also, the outflow opening 95c located at the bottom of the housing chamber 58 is connected to the 2nd discharge flow path 140b. The 2nd discharge flow path 140b communicates with the 2nd intermediate portion 13b of the main flow path 13 in the hydraulic control unit 50 by means of an internal flow path, not shown, formed in the base 51. Figure 1 In other words, the annular flow path 56 constitutes a part of the sub flow path 14. When the pump 60 is housed in the pump housing chamber 53, the suction port 62c of the pump 60 and the 3rd intermediate portion 14a need to communicate. Since the annular flow path 56 is provided, when the pump 60 is housed in the pump housing chamber 53, no alignment for communicating the suction port 62c of the pump 60 and the 3rd intermediate portion 14a is required. Therefore, since the annular flow path 56 is provided, the assembly of the hydraulic control unit 50 becomes easy. Further, since the annular flow path 56 is provided, when the pump housing chamber 53 is machined in the base 51, a part of the sub flow path 14 is also machined. Therefore, it is also possible to reduce the machining cost of the base 51, i.e., the manufacturing cost of the hydraulic control unit 50. Further, since the annular flow path 56 is provided, it is possible to effectively utilize the space on the outer peripheral side of the pump 60 as the sub flow path 14, so it is also possible to downsize the base 51, i.e., the hydraulic control unit 50.

[0057] As Figure 2 shown in the case where the pump 60 and the pulsation damping portion 80 are mounted to the base 51, when the pump 60 is driven, the brake fluid flows as described below.

[0058] The drive shaft 57 is rotated by a drive source not shown, and when the eccentric portion 57a formed in the drive shaft 57 is biased toward the piston 62, the piston 62 is pushed against the pressure cylinder 61 against the force of the piston spring 67. Thus, the pressure in the pump chamber 63 becomes high, the opening portion side valve member 64a is separated from the opening portion side valve seat 64b, and the opening portion side discharge valve 64 opens. Thus, the brake fluid in the pump chamber 63 is discharged from the discharge port 65b to the discharge chamber 54 through the communication hole 61c and the bottomed hole 65a of the cover 65.

[0059] When the eccentric portion 57a formed in the drive shaft 57 starts to rotate in a direction away from the piston 62 as the drive shaft 57 further rotates, the piston 62 moves in a direction away from the pressure cylinder 61 by the force of the piston spring 67. Thus, the pressure in the pump chamber 63 becomes low, the opening portion side valve member 64a seats on the opening portion side valve seat 64b, the opening portion side discharge valve 64 closes, and a suction valve not shown that opens and closes the opening of the bottomed hole 62b of the piston 62 opens. Thus, the brake fluid in the annular flow path 56 flows into the pump chamber 63 through the filter 70, the suction port 62c, and the bottomed hole 62b.

[0060] When the eccentric portion 57a formed in the drive shaft 57 again biases the piston 62 as the drive shaft 57 further rotates, as described above, the piston 62 is pushed against the pressure cylinder 61, and the brake fluid in the pump chamber 63 is discharged from the discharge port 65b to the discharge chamber 54. In this way, the piston 62 repeatedly moves reciprocally in the axial direction of the pressure cylinder 61, and the suction valve not shown and the opening portion side discharge valve 64 selectively open and close, whereby the brake fluid whose pressure has risen, i.e., whose pressure has been boosted, is discharged from the discharge port 65b to the discharge chamber 54. Thus, pulsation occurs in the brake fluid whose pressure has been boosted by the pump 60. The brake fluid accompanying the pulsation flows into the pulsation damping portion 80 via the first discharge flow path 140a.

[0061] <Structure Example and Operation of Pulsation Damping Portion 80>

[0062] Hereinafter, the structure example and operation of the pulsation damping portion 80 will be described with reference to Figures 3 to 5 As described above, the pulsation damping portion 80 is used to dampen the pulsation of the brake fluid generated when the pump 60 is driven, and to dampen the noise caused by the pulsation.

[0063] Figure 3The pulsation damping portion 80 represents a state in which the pump 60 is not driven. The cylindrical accommodation chamber 58 that accommodates the pulsation damping portion 80 is formed in the base 51. The pulsation damping portion 80 is provided with an inflow opening 95b through which the brake fluid flows in and an outflow opening 95c through which the brake fluid flows out. Further, the pulsation damping portion 80 is provided with a fixing member 86 that divides the inside of the pulsation damping portion 80 into an upstream side region on the inflow opening 95b side and a downstream side region on the outflow opening 95c side.

[0064] The cylindrical shape of the accommodation chamber 58 is a stepped shape provided with a small-diameter portion 58b and a large-diameter portion 58d. The large-diameter portion 58d is formed on the cap portion 82 side that closes the opening portion 58e of the accommodation chamber 58, and the small-diameter portion 58b is formed on the bottom portion 58a side of the accommodation chamber 58 on the side opposite the opening portion 58e. Between the small-diameter portion 58b and the large-diameter portion 58d, a step portion 58c is formed in parallel with the bottom portion 58a, in other words, in a direction orthogonal to the axis Axc of the length direction of the pulsation damping portion 80. The inflow opening 95b is formed in the large-diameter portion 58d, and the outflow opening 95c is formed in the bottom portion 58a.

[0065] The fixing member 86 is fixed to the small-diameter portion 58b side of the accommodation chamber 58. The fixing member 86 is provided with a fixing member disc portion 86a in a disc shape, a fixing member outer cylindrical portion 86c in a cylindrical shape formed from the outer peripheral portion of the fixing member disc portion 86a toward the bottom portion 58a side, and a cylindrical portion 86d in a cylindrical shape formed in the central portion of the fixing member disc portion 86a toward the cap portion 82 side. Further, the fixing member disc portion 86a is provided with a fixing member hole 86b that penetrates the fixing member disc portion 86a in the axis Axc direction of the accommodation chamber 58 at a position that is on the outer side in the circumferential direction than the cylindrical portion 86d and on the inner side in the circumferential direction than the fixing member outer cylindrical portion 86c.

[0066] The pulsation damping portion 80 is provided with a guide member 87. The guide member 87 is a stepped hollow cylindrical member provided with a small-diameter portion guide portion 87a that covers the inner surface of the small-diameter portion 58b of the accommodation chamber 58, a bottom portion guide portion 87b that covers the surface of the bottom portion 58a of the accommodation chamber 58, and an outflow opening guide portion 87c that covers the inner surface of the outflow opening 95c. The fixing member outer cylindrical portion 86c is fixed to the small-diameter portion guide portion 87a of the guide member 87 by an appropriate method such as press-fitting or welding.

[0067] On the fixing member 86 side of the large-diameter portion 58d than the inflow opening 95b, an upstream side movable member 84 is provided that is in a disc shape and is able to slide in the axis Axc direction of the accommodation chamber 58. A sliding member 84a is attached to the side surface of the upstream side movable member 84 that faces the large-diameter portion 58d. The sliding member 84a slides with respect to the large-diameter portion 58d when the upstream side movable member 84 moves. In order to make the sliding smooth, PTFE can be used as the material of the sliding member 84a, for example.

[0068] The upstream movable member 84 has a through-hole 84b that penetrates in the axial direction Axc of the accommodation chamber 58 at the central portion. The through-hole 84b has a seat portion 84d in which the valve member 94 can be seated at the lid portion 82 side. The valve member 94 is urged toward the seat portion 84d with a predetermined installation force by a valve spring 93 provided between the surface of the upstream movable member 84 on the lid portion 82 side, i.e., the inner surface 82a of the lid portion, and the valve member 94. On the radial direction outside of the through-hole 84b, a plurality of upstream side holes 84c that are smaller in diameter than the through-hole 84b and that penetrate the upstream movable member 84 in the axial direction Axc of the accommodation chamber 58 are formed.

[0069] In the present embodiment, the region between the upstream movable member 84 and the lid portion 82 of the accommodation chamber 58 is referred to as the inflow opening side damping portion 81a, the region between the upstream movable member 84 and the fixed member 86 is referred to as the fixed member side damping portion 81b, and the region between the fixed member 86 and the bottom portion 58a is referred to as the outflow opening side damping portion 81c. That is, in the accommodation chamber 58, the inflow opening side damping portion 81a and the fixed member side damping portion 81b constitute the upstream side region of the accommodation chamber 58, and the outflow opening side damping portion 81c constitutes the downstream side region of the accommodation chamber 58.

[0070] In the inflow opening side damping portion 81a, an elastic body that exerts a force on the upstream movable member 84 toward the fixed member 86, i.e., an inflow opening side elastic body 92, is provided. In the fixed member side damping portion 81b, an elastic body that exerts a force on the upstream movable member 84 toward the lid portion 82, i.e., a fixed member side elastic body 91, is provided.

[0071] A coil spring can be used as the inflow opening side elastic body 92. The inflow opening side elastic body 92 is disposed on the circumferential direction outside of the valve spring 93 and the upstream side hole 84c.

[0072] The fixed member side elastic body 91 can be provided as a cylindrical cushion member. As the material of the cushion member, for example, a material such as ethylene propylene diene rubber (EPDM) and / or silicon can be used. The fixed member side elastic body 91 is disposed on the radial direction outside of the fixed member hole 86b and the upstream side hole 84c.

[0073] In the case where a cushion member is used as the elastic body, the cushion member can be formed of one material or can be formed of a plurality of materials. For example, the cushion member can be formed with silicon having a relatively high rebound rate sandwiching EPDM having a relatively low rebound rate. By the combination of materials, the rebound rate of the cushion member can be adjusted in accordance with the inherent pulsation frequency of the brake fluid due to the performance of the pump.

[0074] The outflow opening-side damping portion 81c includes a downstream movable member 85 that is slidable in the direction of the axis Axc of the accommodating chamber 58. The downstream movable member 85 includes a cylindrical downstream hole 85c in its center, facing the outflow opening 95c. Furthermore, the downstream movable member 85 includes a first dish portion 85a circumferentially outward of the downstream hole 85c, which is capable of abutting against the fixed member disk portion 86a of the fixed member 86. Alternatively, the downstream hole 85c may be a through-hole extending through the first dish portion 85a rather than a cylindrical hole.

[0075] Furthermore, the downstream movable member 85 is integrally formed with a cylindrical movable member cylindrical portion 85e extending from the outer periphery of the first dish portion 85a toward the bottom portion 58a, and a second dish portion 85d extending radially outward from the upper end of the movable member cylindrical portion 85e. The movable member cylindrical portion 85e forms a space on the top surface of the first dish portion 85a. Furthermore, the outer periphery of the second dish portion 85d is guided by the small-diameter guide portion 87a of the guide member 87.

[0076] The second dish portion 85d is formed at a position such that, when the first dish portion 85a is in contact with the fixed member disc portion 86a of the fixed member 86, a predetermined distance is maintained between the second dish portion 85d and the bottom guide portion 87b of the guide member 87. Furthermore, when the first dish portion 85a is in contact with the fixed member disc portion 86a, the fixed member hole 86b of the fixed member 86 is blocked by the first dish portion 85a, and the downstream side hole 85c of the downstream side movable member 85 is blocked by the fixed member disc portion 86a.

[0077] Between the first dish portion 85a of the downstream movable member 85 and the bottom guide portion 87b of the guide member 87, a hollow cylindrical outflow opening side elastic body 90 is provided to bias the downstream movable member 85 toward the fixed member 86. The outflow opening side elastic body 90 is provided circumferentially outward of the downstream hole 85c and circumferentially inward of the movable member cylindrical portion 85e. The outflow opening side elastic body 90 can also be an elastic body having the same conditions as those for the fixed member side elastic body 91 described above.

[0078] exist Figure 3 In the closed state, i.e., in the state where the pump 60 is not driven, the upstream movable member 84 is subjected to a force acting in the direction of the cover portion 82 from the fixed member-side elastic body 91. On the other hand, it is subjected to a force acting in the direction of the fixed member 86 from the valve spring 93 and the inlet opening-side elastic body 92. As a result, the forces acting on the elastic bodies are adjusted so that the upstream movable member 84 is located between the stepped portion 58c and the inlet opening 95b in the large diameter portion 58d. In this state, the valve member 94 and the cylindrical portion 86d do not abut. In addition, the first disc portion 85a of the downstream movable member 85 abuts against the fixed member disc portion 86a of the fixed member 86.

[0079] When the pump 60 starts to be driven, the brake fluid flows in from the inflow opening 95b, and the pressure of the inflow opening side damper portion 81a rises. When the pressure of the inflow opening side damper portion 81a rises, the valve member 94 and the upstream side movable member 84 move to the fixed member 86 side in a state where the valve member 94 is seated on the seat portion 84d.

[0080] Next, the valve member 94 comes into abutment with the cylindrical portion 86d of the fixed member 86, but the upstream side movable member 84 continues to move. Thereby, the valve member 94 is disengaged from the seat portion 84d at this time. After that, the upstream side movable member 84 comes into abutment with the stepped portion 58c, and thereby the movement ends. That is, the dimensions of the members are set so that the movement amount of the upstream side movable member 84 is larger than the movement amount of the valve member 94.

[0081] Figure 4 This shows a state where the valve member 94 comes into abutment with the cylindrical portion 86d but is still in abutment with the seat portion 84d. After this state, the upstream side movable member 84 further moves to come into abutment with the stepped portion 58c.

[0082] The valve member 94 and the upstream side movable member 84 rise, and thereby the pressure of the fixed member side damper portion 81b also rises. Next, the valve member 94 is disengaged from the seat portion 84d, and thereby the brake fluid flows from the inflow opening side damper portion 81a to the fixed member side damper portion 81b through the through hole 84b, so the pressure of the fixed member side damper portion 81b further rises. And, the rise in the pressure of the fixed member side damper portion 81b acts on the downstream side movable member 85 through the fixed member hole 86b, overcomes the force of the outflow opening side elastic body 90, and moves the downstream side movable member 85 to the bottom portion 58a side.

[0083] Figure 5 This shows a state where the downstream side movable member 85 moves to the bottom portion 58a side. The downstream side movable member 85 moves to the bottom portion 58a side, and thereby the fixed member hole 86b blocked by the downstream side movable member 85 is opened, and the brake fluid flows out from the fixed member side damper portion 81b to the outflow opening side damper portion 81c via the fixed member hole 86b. The brake fluid that flows out to the outflow opening side damper portion 81c flows out to the outside of the pulsation damping portion 80 through the downstream side hole 85c formed at the downstream side movable member 85 from the outflow opening 95c.

[0084] In addition, Figure 5 The second disc portion 85d of the downstream side movable member 85 comes into abutment with the bottom portion guide portion 87b. That is, the position of the second disc portion 85d before the pump 60 is driven defines the movement amount of the downstream side movable member 85 at the time when the pump 60 is driven.

[0085] Further, in a state where the pump 60 is just driven and the valve member 94 is seated in the seat portion 84d, the brake fluid flowing into the inflow opening side damper portion 81a also flows out to the fixed member side damper portion 81b little by little through the upstream side hole 84c formed at the upstream side movable member 84. Thus, it is possible to prevent a situation where the pressure in the fixed member side damper portion 81b sharply rises after the valve member 94 is detached from the seat portion 84d.

[0086] Further, the downstream side hole 85c is provided at the central portion of the downstream side movable member 85, and the fixed member holes 86b are formed at a plurality of positions on the outer side in the circumferential direction than the downstream side hole 85c. By providing such a structure, the brake fluid flows toward the center through the plurality of fixed member holes 86b, and the brake fluid flowing out from each of the fixed member holes 86b collides near the downstream side hole 85c, and the flow of the brake fluid becomes weak. As a result, it is possible to stabilize the flow of the brake fluid.

[0087] Further, by the action of each of the elastic bodies, the rapid action of the upstream side movable member 84 and the downstream side movable member 85 is hindered, and it is possible to stabilize the flow of the brake fluid.

[0088] As described above, according to the present application, by the action of each of the elastic bodies, the rapid action of the upstream side movable member 84 and the downstream side movable member 85 is hindered, and by the action of each of the holes, the rapid flow of the brake fluid is hindered, and thus, it is possible to stabilize the flow of the brake fluid and attenuate the pressure pulsation in the pulsation attenuation portion 80. As a result, it is possible to attenuate the noise caused by the pulsation generated when the pump 60 is driven.

[0089] Explanation of Reference Numerals

[0090] 51: base, 58: accommodation chamber, 58a: bottom, 60: pump, 80: pulsation attenuation portion, 81a: inflow opening side damper portion, 81b: fixed member side damper portion, 81c: outflow opening side damper portion, 82: cover portion, 84: upstream side movable member, 84b: through hole, 84c: upstream side hole, 84d: seat portion, 85: downstream side movable member, 85c: downstream side hole, 86: fixed member, 86b: fixed member hole, 86d: cylindrical portion, 90: outflow opening side elastic body, 91: fixed member side elastic body, 92: inflow opening side elastic body, 94: valve member, 95b: inflow opening, 95c: outflow opening.

Claims

1. A pump device, the pump device being provided in a base (51) and comprising a pulsation damping portion (80) for damping pulsation of brake fluid discharged from a pump (60), wherein: The pulsation attenuation unit (80) includes: a cylindrical receiving chamber (58) provided on the base (51); a fixing member (86) for dividing the accommodation chamber (58) into an upstream area and a downstream area; An upstream movable member (84) equipped in the upstream region and capable of sliding in the axial direction; an inflow opening-side damping portion (81a) communicating with an inflow opening (95b) through which the brake fluid flows and formed between the upstream movable member (84) and a cover portion (82) of the accommodating chamber (58); and a fixed member-side damping portion (81b) formed between the upstream movable member (84) and the fixed member (86); a downstream movable member (85) provided in the downstream region and capable of sliding in the axial direction; an outflow opening-side damping portion (81c) communicating with an outflow opening (95c) through which the brake fluid flows out and formed between the downstream movable member (85) and the bottom (58a) of the accommodating chamber (58); a fixing member hole (86b) formed in the fixing member (86); a downstream side hole (85c) formed in the downstream side movable member (85); an inflow opening side elastic body (92) provided on the inflow opening side damping portion (81a) for urging the upstream side movable component (84) toward the fixed component (86); a fixed component side elastic body (91) provided on the fixed component side damping portion (81b) for urging the upstream side movable component (84) toward the cover portion (82); and An outflow opening side elastic body (90) provided on the outflow opening side damping portion (81c) for urging the downstream side movable member (85) toward the fixed member (86) side, The fixing member (86) includes a cylindrical portion (86d) extending toward the cover portion (82). The upstream movable member (84) has a through hole (84b), and the through hole (84b) has a seat portion (84d). The seat portion (84d) is configured to be closed by seating the valve member (94) pushed from the cover portion (82). During the process in which the upstream side movable member (84) moves toward the fixed member (86) side by the pressure caused by the brake fluid flowing into the inlet opening side damping portion (81a), the valve member (94) abuts against the cylindrical portion (86d) and detaches from the seat portion (84d), thereby causing the brake fluid to flow from the through hole (84b) and the pressure of the fixed member side damping portion (81b) to rise. With the help of the pressure increase of the damping part (81b) on the fixed part side, the downstream side movable part (85) abutting against the fixed part (86) moves toward the bottom (58a) side, and the brake fluid flows out from the outflow opening (95c) through the fixed part hole (86b) and the downstream side hole (85c).

2. The pump device according to claim 1, wherein The downstream side hole (85c) is formed at the radial center of the downstream side movable component (85), and a plurality of the fixed component holes (86b) are formed radially outward of the downstream side hole (85c) when viewed in the axial direction.

3. The pump device according to claim 1 or 2, characterized in that The upstream movable component (84) has an upstream hole (84c) on the radially outer side of the through hole (84b) for communicating the inflow opening side damping portion (81a) and the fixed component side damping portion (81b).

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