WO2024105476A1

WO2024105476A1 - Dampening device, liquid-pressure control unit, and brake system

Info

Publication number: WO2024105476A1
Application number: PCT/IB2023/060455
Authority: WO
Inventors: 貴紀坂本
Original assignee: ロベルト•ボッシュ•ゲゼルシャフト•ミト•ベシュレンクテル•ハフツング
Priority date: 2022-11-16
Filing date: 2023-10-17
Publication date: 2024-05-23

Abstract

An attenuation device (100) includes a first liquid chamber (S1) configured to communicate with an inlet port (P1) through a first opening (PO1); a second liquid chamber (S2) configured to communicate with the first liquid chamber (S1) through a communication hole (113c) and with an outlet port (P2) through a second opening (PO2); a first piston (121) provided in the first liquid chamber (S1); a first biasing member (141) configured to bias the first piston (121) toward side of the first opening (PO1); a bore portion (121e) formed in the first piston (121) to be recessed from side of the second opening (PO2) toward the side of the first opening (PO1); a second piston (122) provided in the bore portion (121e); a second biasing member (142) configured to bias the second piston (122) toward the side of the first opening (PO1); a first through hole (122c) provided through the second piston (122) from the side of the first opening (PO1) to the side of the second opening (PO2); a first valve body (151) capable of opening and closing the side of the first opening (PO1) of the first through hole (122c); a third biasing member (143) configured to bias the first valve body (151) toward the side of the second opening (PO2); a protruding member (161) that includes a protruding portion (161c) capable of being inserted into the first through hole (122c) and capable of coming into contact with the first valve body (151), and provided at part of the first piston (121) on the side of the second opening (PO2) with respect to the second piston (122); a second valve body (152) that is capable of opening and closing the side of the second opening (PO2) of the communication hole (113c); and a fourth biasing member (144) configured to bias the second valve body (152) toward the side of the first opening (PO1).

Description

[Document name] Statement

[Title of invention] Damping device, hydraulic control unit and brake system

【Technical field】

[.001] The present invention relates to a damping device, a hydraulic control unit, and a brake system.

[Background Art]

[.002] In conventional vehicles, a hydraulic control unit is provided to control the braking force applied to the wheels. For example, as disclosed in Patent Document 1, a plurality of valves and a pump are provided in the flow path within the hydraulic control unit. In such a hydraulic control unit, for example, in anti-lock brake control or anti-skid control, the opening and closing states of each valve are set to specific states, and the pump is driven.

[Prior art references]

[Patent documents]

【〇 0 0 3】

[Patent Document 1] JP 2010-052519 A

Summary of the Invention

[Problem to be solved by the invention]

[0004] In the hydraulic control unit, a reciprocating plunger pump is mainly used as the pump. Therefore, the pump pressurizes the brake fluid intermittently. Therefore, when the pump is driven, pressure pulsation occurs, which is a phenomenon in which the hydraulic pressure of the brake fluid pulsates in the flow path in the hydraulic control unit. The sound generated by such pressure pulsation may be perceived as noise by the vehicle occupants, and may be a factor that reduces comfort. Therefore, from the viewpoint of improving comfort, it is desirable to appropriately damp the pressure pulsation of the hydraulic control unit.

[0005] In view of the above problems, the present invention aims to provide a damping device capable of damping pressure pulsations of a hydraulic control unit, a hydraulic control unit, and a brake system.

[Means for solving the problem]

[0006] In order to achieve the above object, a damping device is provided in a hydraulic control unit that controls a braking force generated on a wheel, and has an inlet port connected to a discharge side of a pump and an outlet port that communicates with the inlet port, and damps pressure pulsation, the damping device comprising: a first fluid chamber that communicates with the inlet port via a first opening; a second fluid chamber that communicates with the first fluid chamber via a communication hole and with the outlet port via a second opening; a first piston slidably provided in the first fluid chamber; a first biasing member that biases the first piston toward the first opening side; a hole portion that is recessed from the second opening side toward the first opening side in the first piston; a second piston slidably provided in the hole portion; the first through hole penetrating from the first opening side to the second opening side, a first valve body capable of opening and closing the first opening side of the first through hole, a third biasing member biasing the first valve body toward the second opening side, a protrusion member capable of being inserted into the first through hole and having a protrusion capable of abutting against the first valve body, the protrusion member being provided on the second opening side of the first piston with respect to the second piston and moving integrally with the first piston, a second valve body provided in the second liquid chamber and capable of opening and closing the second opening side of the communication hole, and a fourth biasing member biasing the second valve body toward the first opening side.

[0007] In order to solve the above problem, the hydraulic control unit is equipped with the above damping device.

[0008] In order to solve the above problem, the brake system is equipped with the above hydraulic control unit.

【Effect of the invention】 [0009] According to the present invention, it is possible to damp the pressure pulsation of the hydraulic control unit.

[Brief description of the drawings]

[ 0 0 1 0 ]

[Figure 1] Schematic diagram showing the general configuration of a brake system according to an embodiment of the present invention.

[Figure 2] A cross-sectional view showing a schematic configuration of a damping device according to an embodiment of the present invention.

FIG. 3 is a diagram showing a state in which a first piston has moved to the right compared to the state in FIG. 2 in the damping device according to the embodiment of the present invention.

FIG. 4 is a diagram showing a state in which a second piston has moved to the right compared to the state in FIG. 3 in the damping device according to the embodiment of the present invention.

FIG. 5 is a diagram showing a state in which the first piston and the second piston have moved to the right compared to the state in FIG. 4 in the damping device according to the embodiment of the present invention.

[Mode for carrying out the invention]

[0011] Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings. The dimensions, materials, and other specific values shown in the embodiments are merely examples for facilitating understanding of the invention, and do not limit the present invention unless otherwise specified. In this specification and drawings, elements having substantially the same functions and configurations are denoted by the same reference numerals to avoid repetitive explanations, and elements not directly related to the present invention are not illustrated.

[0012] In this embodiment, a vehicle having four wheels 17 will be described as an example of a vehicle. However, the vehicle to which the present invention is applied is not limited to a vehicle having four wheels 17. For example, the vehicle may be a vehicle having one, two, or three wheels 17, or a vehicle having five or more wheels 17.

[ 0 0 1 3 ]

<Configuration of Brake System> The configuration of a brake system according to an embodiment of the present invention will be described with reference to FIG.

[0014] Fig. 1 is a schematic diagram showing the general configuration of a brake system 1. The brake system 1 is installed in a vehicle and is a system for controlling the braking force generated in the vehicle. As shown in Fig. 1, the brake system 1 includes a brake pedal 11, a brake multiplier 12, a master cylinder 13, a reservoir 14, a hydraulic control unit 15, a brake device 16, and wheels 17.

[0015] Brake system 1 is mounted on a vehicle having four wheels 17, and each wheel 17 is braked by a brake device 16 provided on each wheel 17. The braking force generated on each wheel 17 is controlled by a hydraulic control unit 15. In order to facilitate understanding, FIG. 1 shows only a portion of brake system 1 related to one of the front wheels and rear wheels, and does not show a portion related to the other of the front wheels and rear wheels.

[0016] The number of wheels 17 whose braking force is controlled by the hydraulic control unit according to the present invention may be other than four. For example, the number of wheels 17 whose braking force is controlled by the hydraulic control unit 15 may be two. In that case, the brake system 15 may be installed in a vehicle having two wheels 17.

[0017] The brake pedal 11 is used by the driver to apply the brakes. In applying the brakes, the driver depresses the brake pedal 11. The brake booster 12 is connected to the brake pedal 11 and amplifies the depressing force of the brake pedal 11. Master cylinder The master cylinder 13 is connected to the brake fluid multiplier 12, has a built-in piston that reciprocates in conjunction with the brake pedal 11, and generates hydraulic pressure according to the amount of brake operation. The reservoir 14 is attached to the master cylinder 13 and stores brake fluid.

[0018] The hydraulic control unit 15 has a base 15a in which a flow path for brake fluid is formed. The master cylinder 13 and each brake device 16 are connected to the base 15a of the hydraulic control unit 15. The flow path for brake fluid in the base 15a of the hydraulic control unit 15 is connected to the wheel cylinder of the brake device 16. A braking force corresponding to the hydraulic pressure of the brake fluid in the wheel cylinder of the brake device 16 is generated in the wheel 1?.

[0019] A main flow path 21, a sub-flow path 22, and a supply flow path 23 are formed in a base body 15a of a hydraulic control unit 15 as flow paths for brake fluid. The main flow path 21 circulates the brake fluid in the master cylinder 13 to the wheel cylinder of the braking device 16. The sub-flow path 22 releases the brake fluid in the wheel cylinder of the braking device 16. The supply flow path 23 supplies the brake fluid in the master cylinder 13 to the sub-flow path 22.

[0020] The base 15a of the hydraulic control unit 15 is provided with an inlet valve (EV) 31, a release valve (AV) 32, a first valve (USV) 33, a second valve (HSV) 34, an accumulator 35, a pump 36, and a motor 37 as components for controlling the braking force generated on each wheel 17.

[0021] The configuration of the hydraulic control unit according to the present invention may be different from the configuration of hydraulic control unit 15 shown in Fig. 1 as long as it has pump 36. For example, a hydraulic control unit according to the present invention also includes a hydraulic control unit obtained by omitting supply flow path 23, first valve 33, and second valve 34 from hydraulic control unit 15 shown in Fig. 1.

[0022] The main flow path 21 communicates between the master cylinder 13 and the wheel cylinder of the braking device 16. The main flow path 21 includes a first main flow path 21a and two second main flow paths 21b. The first main flow path 21a is connected to the master cylinder 13. The two second main flow paths 21 branch off from the first main flow path 21a and are connected to each braking device 16. A first valve 33 is provided in the first main flow path 21a. An inlet valve 31 is provided in the second main flow path 21b.

[0023] The sub-path 22 communicates between the brake device 16 side of the main path 21 via the inlet valve 31, the master cylinder 13 side of the main path 21 via the inlet valve 31, and the brake device 16 side via a first valve 33. The sub-path 22 includes two first sub-paths 22a and a second sub-path 22b. Each of the first sub-paths 22a is connected to the brake device 16 side of the main path 21 via the inlet valve 31. The second sub-path 22b connects the joining point of the two first sub-paths 22a to the master cylinder 13 side of the main path 21 via the inlet valve 31 and to the brake device 16 side of the first valve 33. A release valve 32 is provided in the first sub-path 22a. An accumulator 35 and a pump 36 are provided in the second sub-path 22b, in this order from the first sub-path 22a side.

[0024] The pump 36 is driven by the motor 37, and sucks brake fluid from the first sub-path 22a side and discharges it to the main path 21 side. The pump 36 is a reciprocating plunger pump. Specifically, the plunger of the pump 36 reciprocates by being intermittently pressed by an eccentric cam provided on the output shaft of the motor 37. This causes the pump 36 to pump out brake fluid.

[0025] The supply flow path 23 communicates between the master cylinder 13 side of the first valve 33 in the main flow path 21 and the suction side of the pump 36 in the sub-flow path 22. A second valve 34 is provided in the supply flow path 23. [0026] The inlet valve 31 is, for example, a solenoid valve that is opened in a de-energized state and closed in an energized state. The release valve 32 is, for example, a solenoid valve that is closed in a de-energized state and opened in an energized state. The first valve 33 is, for example, a solenoid valve that is opened in a de-energized state and closed in an energized state. The second valve 34 is, for example, a solenoid valve that is closed in a de-energized state and opened in an energized state. By controlling the operation of these valves and the motor 37, the braking force generated in each wheel 1? is controlled.

[0027] For example, during normal operation when antilock brake control or anti-skid control, which will be described later, is not being executed, the inlet valve 31 is opened, the release valve 32 is closed, the first valve 33 is opened, and the second valve 34 is closed. As a result, the brake fluid flows from the master cylinder 13 to the wheel cylinder of the brake device 16 only through the main flow path 21, without passing through the sub-flow path 22 and the supply flow path 23. When the brake pedal 11 is depressed in this state, the piston of the master cylinder 13 is pressed, increasing the hydraulic pressure of the brake fluid in the wheel cylinder, and applying a braking force to the wheel 17.

[0028] The antilock brake control is a control for preventing the wheels 17 from locking. For example, when the antilock brake control is executed, first, the inlet valve 31 is closed, the release valve 32 is opened, the first valve 33 is opened, and the second valve 34 is closed. This stops the flow of brake fluid between the main flow path 21 and the wheel cylinder of the brake device 16, and allows the brake fluid to flow from the wheel cylinder to the sub-flow path 22. Therefore, the brake fluid flows from the wheel cylinder to the accumulator 35, the hydraulic pressure of the brake fluid in the wheel cylinder decreases, and the braking force applied to the wheel 17 decreases. The brake fluid that has flowed into the accumulator 35 is returned to the main flow path 21 via the sub-flow path 22 by driving the pump 36.

[0029] Then, from the above state, both inlet valve 31 and release valve 32 are closed, stopping the flow of brake fluid between main flow path 21 and sub flow path 22 and the wheel cylinder, maintaining the hydraulic pressure of the brake fluid in the wheel cylinder and maintaining the braking force applied to the wheel 17. Thereafter, inlet valve 31 is opened and release valve 32 is closed, restarting the flow of brake fluid between main flow path 21 and the wheel cylinder, increasing the hydraulic pressure of the brake fluid in the wheel cylinder, and increasing the braking force applied to the wheel 17.

[0030] Anti-skid control is a control for stabilizing the behavior of a vehicle. In anti-skid control, the driving force and braking force of the vehicle are appropriately controlled. For example, when the vehicle is braked without brake operation during execution of anti-skid control, the inlet valve 31 is opened, the release valve 32 is closed, the first valve 33 is closed, and the second valve 34 is opened. As a result, the brake fluid flows from the master cylinder 13 to the wheel cylinder of the brake device 16 through the supply flow path 23 and the sub-flow path 22. In this state, the pump 36 is driven to increase the hydraulic pressure of the brake fluid in the wheel cylinder, and a braking force that brakes the wheel 17 is generated.

[0031] As described above, the hydraulic control unit 15 controls the driving of the pump 36. When the pump 36 is driven, pressure pulsation occurs, which is a phenomenon in which the hydraulic pressure of the brake fluid pulsates in the flow path in the hydraulic control unit 15. The sound generated by such pressure pulsation may be perceived as noise by the vehicle occupants, which may cause a decrease in comfort. Therefore, the hydraulic control unit 15 is provided with a damping device 100 that damps the pressure pulsation.

[0032] The damping device 100 is provided in the sub-flow path 22 (specifically, the second sub-flow path 22b) downstream of the pump 36. The damping device 100 has an inlet port P1, an outlet port P2, and The inlet port P1 is connected to the discharge side of the pump 36. The inlet port P1 and the outlet port P2 are connected to each other. Therefore, the brake fluid discharged from the pump 36 flows into the damping device 1 XX through the inlet port P!, passes through the damping device 1 XX, and then flows out of the damping device 1 XX through the outlet port P2.

[ 0 0 3 3 ]

<Configuration of the damping device> With reference to Figure 2, the configuration of the damping device 100 according to an embodiment of the present invention will be described.

[0034] Fig. 2 is a cross-sectional view showing a schematic configuration of a damping device 100. However, the damping device 100 shown in Fig. 2 is merely one example of a damping device according to the present invention, and as will be described later, damping devices according to the present invention also include those obtained by adding various modifications to the example of Fig. 2.

[0035] In FIG. 2 and FIG. 3 to FIG. 5 described later, the damping device 100 is shown so that the axial direction of the housing 101 is the left-right direction, the first opening PO! connected to the inlet port P1 is located on the left side in the axial direction, and the second opening PO2 connected to the outlet port P2 is located on the right side in the axial direction. Hereinafter, the left-right direction, which is the axial direction of the housing 101, is also simply referred to as the axial direction. The first opening PO1 side means the side facing the first opening PO1 with the second opening PO2 as the reference in the axial direction (the left side in FIG. 2 to FIG. 5), or the upstream side of the flow direction of the brake fluid from the first opening PO1 to the second opening PO2. The second opening PO2 side means the side facing the second opening PO2 in the axial direction with the first opening PO1 as the reference (the right side in Figures 2 to 5), or the downstream side in the flow direction of the brake fluid from the first opening PO1 to the second opening PO2.

[0036] As shown in FIG. 2, the damping device 100 includes a housing 101, a first cover 111, a second cover 112, a third cover 113, a fourth cover 114, a first piston 121, a second piston 122, a first seal member 131, a second seal member 132, a first urging member 141, a second urging member 142, a third urging member 143, a fourth urging member 144, a first valve body 151, a second valve body 152, a protrusion member 161, and a buffer member. 1 7 1 Equipped with

[0037] The housing 101 is formed, for example, in a cylindrical shape having a hollow space inside. The axial direction of the housing 101 is the left-right direction. The housing 101 has an internal space that penetrates from the left end face to the right end face. The internal space of the housing 101 includes a first hole portion 101a and a second hole portion 101b. Each of the first hole portion 101a and the second hole portion 101b has a cylindrical shape and is arranged coaxially with the central axis of the housing 101. The first hole portion 101a and the second hole portion 101b are continuous in this order from the left side. The diameter of the second hole portion 101b is smaller than the diameter of the first hole portion 101a.

[0038] A first cover 111 is fitted into the first hole portion 101a. The first cover 111 has a generally circular plate shape. A left end portion of the outer circumferential surface of the first cover 111 expands in diameter radially outward. The portion of the first cover 111 that expands in diameter radially outward is fitted into the first hole portion 101a.

[0039] A third cover 113 is fitted into the second hole portion 101b. The third cover 113 has a substantially cylindrical shape. The third cover 113 has a first cylindrical portion 113a and a second cylindrical portion 113b. The first cylindrical portion 113a and the second cylindrical portion 113b have a cylindrical shape and are arranged coaxially with each other. The first cylindrical portion 113a and the second cylindrical portion 113b are continuous in this order from the right side. The outer diameter of the second cylindrical portion 113b is smaller than the outer diameter of the first cylindrical portion 113a. The first cylindrical portion 113a is fitted into the right end portion of the second hole portion 101b. The outer peripheral surface of the second cylindrical portion 113 b is radially spaced apart from the inner peripheral surface of the second hole portion 101 b.

[ 0 0 4 0 ]

The first biasing member 141 is, for example, an elastic member such as a spring. The first biasing member 141 is disposed between the first piston 121 and the third cover 113. One end (the left end in FIG. 2) of the first biasing member 141 abuts against the right end surface of the first piston 121. The other end (the right end in FIG. 2) of the first biasing member 141 abuts against the left surface of the first cylindrical portion 113a of the third cover 113. The first biasing member 141 expands and contracts in the left-right direction. The first biasing member 141 is in a contracted state relative to its natural length.

[0048] A hole 121d is formed on the left side of the first piston 121. The hole 121d is a portion of the first piston 121 that is recessed from the left side to the right side. The hole 121d is recessed from the left end face of the first piston 121 to the right side. The hole 121d has a cylindrical shape and is disposed coaxially with the central axis of the housing 101. However, the hole 121d does not have to be disposed coaxially with the central axis of the housing 101.

[0049] A hole 121e is formed on the right side of the first piston 121. The hole 121e is a portion of the first piston 121 that is recessed from the right side to the left side. The hole 121e is recessed from the right end face of the first piston 121 to the left side. The hole 121e has a cylindrical shape and is disposed coaxially with the central axis of the housing 101. However, the hole 121e does not have to be disposed coaxially with the central axis of the housing 101.

[0050] Hole portion 121d and hole portion 121e are communicated with each other. Thus, hole portion 121d and hole portion 121e penetrate first piston 121 from the left side to the right side. Hole portion 121d and hole portion 121e are continuous in this order from the left side and are arranged coaxially with each other. The inner diameter of hole portion 121d is smaller than the inner diameter of hole portion 121e.

[0051] The second piston 122 is housed in the hole 121e. The second piston 122 has a substantially cylindrical shape. The second piston 122 is disposed coaxially with the central axis of the hole 121e. The outer peripheral surface of the second piston 122 is slidable against the inner peripheral surface of the hole 121e. Therefore, the second piston 122 is provided in the hole 121e so as to be slidable in the axial direction.

[0052] An annular groove 122a is formed on the outer circumferential surface of the second piston 122. The annular groove 122a extends in the circumferential direction of the second piston 122. A second seal member 132 is fitted into the annular groove 122a. The second seal member 132 is, for example, an O ring. The second seal member 132 is pressed against the inner circumferential surface of the hole 121e. This provides a liquid-tight seal to the gap between the outer circumferential surface of the second piston 122 and the inner circumferential surface of the hole 121e.

[0053] The second piston 122 is urged to the left by the second urging member 142. The second urging member 142 is, for example, an elastic member such as a spring. As will be described later, a protrusion member 161 is fitted into the right end portion of the inner circumferential surface of the hole portion 121e. The second urging member 142 is disposed between the second piston 122 and the protrusion member 161. One end of the second urging member 142 (the left end in FIG. 2) abuts against the right surface of the second piston 122. Specifically, in the example of FIG. 2, the center of the right surface of the second piston 122 protrudes to the right, and one end of the second urging member 142 abuts against the surface surrounding the protruding portion. The other end (the right end in FIG. 2) of the second urging member 142 abuts against the left surface of the first cylindrical portion 161a of the protruding member 161 described later. Specifically, in the example of FIG. 2, a ring-shaped groove extending in the circumferential direction is provided on the left surface of the first cylindrical portion 161a of the protruding member 161, and the other end of the second urging member 142 abuts against the bottom surface of the groove. The second urging member 142 expands and contracts in the left-right direction. The second urging member 142 is in a contracted state relative to its natural length.

[0054] A hole 122b is formed on the left side of the second piston 122. The hole 122b is a portion of the second piston 122 that is recessed from the left side to the right side. Hole 122b is recessed to the right side from the left end face of piston 122. Hole 122b has a substantially cylindrical shape and is disposed coaxially with the central axis of hole 121e. However, hole 122b does not have to be disposed coaxially with the central axis of hole 121e.

[0055] A fourth cover 114 is fitted into the left end of the inner circumferential surface of hole 122b. The fourth cover 114 is formed in a disk shape with a through hole 114a in the center. The through hole 114a penetrates the fourth cover 114 from the left side to the right side. The left end of the inner circumferential surface of hole 122b has an expanded diameter. The fourth cover 114 is fitted into the expanded diameter portion of the inner circumferential surface of hole 122b. A space in the first fluid chamber S! to the left of the second piston 122 and hole 122b communicate with each other via the through hole 114a of the fourth cover 114.

[0056] The second piston 122 is provided with a first through hole 122c that penetrates from the bottom of the hole 122b (the right part in FIG. 2) to the right end face of the second piston 122. The first through hole 122c penetrates the second piston 122 from the left side to the right side. The hole 122b and the first through hole 122c are continuous in this order from the left side and are arranged coaxially with each other. The inner diameter of the first through hole 122c is smaller than the inner diameter of the hole 122b.

[0057] The second piston 122 has a plurality of third through holes 122d formed therein, which are different from the first through holes 122c. The third through holes 122d penetrate the second piston 122 from the left side to the right side. In the example of FIG. 2, the third through holes 122d are arranged around the first through holes 122c and extend from the right side of the inner surface of the hole portion 122b to the right end surface of the second piston 122. The inner diameter of the third through holes 122d is, for example, about 0.4 mm to 0.5 mm in diameter. In the example of FIG. 2, the third through holes 122d extend in the axial direction. However, the path of the third through hole 122d is not particularly limited. For example, the third through hole 122d may extend in a direction inclined with respect to the axial direction, or may be curved or bent.

[0058] The third through holes 122d are arranged at equal intervals in the circumferential direction of the second piston 122. However, the arrangement of the third through holes 122d is not limited to this example. For example, the third through holes 122d may be arranged at unequal intervals in the circumferential direction. The number of the third through holes 122d may be one. The brake fluid can flow from the left side to the right side of the second piston 122 through the third through hole 122d. In particular, even when the first valve body 151 described later is in a closed state, the brake fluid can flow from the left side to the right side of the second piston 122 through the third through hole 122d. The third through hole 122d is provided to enhance the effect of reducing pressure pulsation. The function of the third through hole 122d will be described later.

[0059] The first valve body 151 is provided in the hole portion 122b and can open and close the left side of the first through hole 122c. In an open state in which the first valve body 151 does not block the first through hole 122c, brake fluid can flow through the first through hole 122c. This state corresponds to the open state of the first valve body 151 and the open state of the first through hole 122c. In a closed state in which the first valve body 151 blocks the first through hole 122c, brake fluid cannot flow through the first through hole 122c. This state corresponds to the closed state of the first valve body 151 and the closed state of the first through hole 122c.

[0060] The first valve body 151 has, for example, a spherical shape. However, the shape of the first valve body 151 may be a shape other than a spherical shape. The third biasing member 143 is, for example, an elastic member such as a spring. The third biasing member 143 is disposed between the fourth cover 114 and the first valve body 151. The third biasing member 143 expands and contracts in the left-right direction. The third biasing member 143 is in a contracted state relative to its natural length. Therefore, the first valve body 151 is biased to the right by the third biasing member 143.

[ 0 0 6 1 ] The protrusion member 161 is provided to open and close the first valve body 151. The protrusion member 161 is attached to the first piston 121 and moves integrally with the first piston 121. The protrusion member 161 is provided on the right side of the first piston 121 with respect to the second piston 122. Specifically, the protrusion member 161 is fitted into the right end of the inner circumferential surface of the hole portion 121e.

[0062] The protrusion member 161 has a first cylindrical portion 161a, a second cylindrical portion 161b, and a protrusion 161c. The first cylindrical portion 161a, the second cylindrical portion 161b, and the protrusion 161c have a substantially cylindrical shape and are arranged coaxially with each other. The first cylindrical portion 161a, the second cylindrical portion 161b, and the protrusion 161c are continuous in this order from the right side. The outer diameters of the first cylindrical portion 161a, the second cylindrical portion 161b, and the protrusion 161c decrease in this order. The first cylindrical portion 161a is fitted into a right end portion of the inner circumferential surface of the hole 121e. The outer circumferential surface of the second cylindrical portion 161b is radially spaced apart from the inner circumferential surface of the hole 121e. The protrusion 161c protrudes to the left from the left face of the second cylindrical portion 161b.

[0063] The protrusion 161c is disposed coaxially with the first through hole 122c of the second piston 122. When the second piston 122 moves relatively to the right with respect to the first piston 121 from the position shown in Fig. 2, the protrusion 161c can be inserted into the first through hole 122c and a tip of the protrusion 161c can abut against the first valve body 151. When the tip of the protrusion 161c abuts against the first valve body 151, the relative position of the first valve body 151 with respect to the first piston 121 is maintained. In this state, the second piston 122 further moves to the right relative to the first piston 121, whereby the first valve body 151 is opened. In this manner, the protrusion 161c can be inserted into the first through hole 122c and can come into contact with the first valve body 151.

[0064] A hole 161d is formed on the right side of the protrusion member 161. The hole 161d is a portion of the protrusion member 161 that is recessed from the right side to the left side. The hole 161d is recessed from the right end face of the protrusion member 161 to the left side. The hole 161d is disposed coaxially with the central axis of the hole 121e. However, the hole 161d does not have to be disposed coaxially with the central axis of the hole 121e.

[0065] A plurality of second through holes 161e are formed in the protruding member 161. The second through holes 161e penetrate the protruding member 161 from the left side to the right side. In the example of FIG. 2, the second through holes 161e extend from the left side surface of the second cylindrical portion 161b to the bottom of the hole portion 161d (the left side portion in FIG. 2). The inner diameter of the second through holes 161e is, for example, about 0.4 mm to 0.5 mm in diameter. In the example of FIG. 2, the second through holes 161e extend in the axial direction. However, the path of the second through hole 161e is not particularly limited, and for example, the second through hole 161e may extend in a direction inclined with respect to the axial direction, or may be curved or bent.

[0066] The second through holes 161e are arranged at equal intervals in the circumferential direction of the protruding member 161. However, the arrangement of the second through holes 161e is not limited to this example. For example, the second through holes 161e may be arranged at unequal intervals in the circumferential direction. The number of second through holes 161e may be one. The brake fluid can flow from the left side to the right side of the protruding member 161 through the second through hole 161e. The second through hole 161e is provided to enhance the effect of reducing pressure pulsation. The function of the second through hole 161e will be described later.

[0067] The second valve body 152 is provided in the second fluid chamber S2 and is capable of opening and closing the right side of the communication hole 113c. In an open state in which the second valve body 152 does not block the communication hole 113c, brake fluid can flow through the communication hole 113c. This state corresponds to the open state of the second valve body 152 and the open state of the communication hole 113c. In a closed state in which the second valve body 152 blocks the communication hole 113c, brake fluid cannot flow through the communication hole 113c. This state corresponds to the open state of the second valve body 152 and the open state of the communication hole 113c. This corresponds to the closed state of hole 152 and the closed state of communicating hole 113c.

[0068] The second valve body 152 has a head 152a, a first shaft portion 152b, and a second shaft portion 152c. The head 152a has a substantially hemispherical shape. The left side of the head 152a is spherical and can open and close the communication hole 113c. The first shaft portion 152b extends to the right from the right surface of the head 152a. The second shaft portion 152c extends to the right from the right surface of the first shaft portion 152b. The outer diameter of the second shaft portion 152c is smaller than the outer diameter of the first shaft portion 152b. The cross-sectional shape of the first shaft portion 152 b and the second shaft portion 152 c is, for example, a circular or polygonal shape. The first shaft portion 152 b and the second shaft portion 152 c are arranged coaxially with the central axis of the housing 101. A through hole 112 a is formed in the center of the second cover 112, and the second shaft portion 152 c is inserted into the through hole 112 a.

[0069] The fourth biasing member 144 is, for example, an elastic member such as a spring. The fourth biasing member 144 is disposed between the second cover 112 and the second valve body 152. The fourth biasing member 144 expands and contracts in the left-right direction. The fourth biasing member 144 is in a contracted state relative to its natural length. Therefore, the second valve body 152 is biased to the left by the fourth biasing member 144.

[0070] The cushioning member 171 is provided to reduce the impact when the first piston 121 collides with the first cover 111. The cushioning member 171 is a member that easily absorbs impact, such as rubber. The cushioning member 171 is provided on the left side of the first piston 121. Specifically, the cushioning member 171 is attached to the left end of the first piston 121 and moves integrally with the first piston 121. As shown in FIG. 2, when the first piston 121 is located at the leftmost position in its movable range, the cushioning member 171 comes into contact with the first cover 111. In this manner, the buffer member 171 is arranged so as to be able to come into contact with the first cover 111.

[ 0 0 7 1 ]

<Operation of the damping device> The operation of the damping device 100 according to the embodiment of the present invention will be described with reference to Figures 2 to 5.

[0072] FIG. 2 above shows the damping device 100 in the hydraulic control unit 15 under normal conditions when the pump 36 is not driven. In this case, the first piston 121 is biased to the left by the first biasing member 141 and is located at the leftmost position in the movable range. The second piston 122 is biased to the left by the second biasing member 142 and is located at the leftmost position in the movable range. The left end face of the first piston 121 abuts against the first cover 111 via the buffer member 171. The left end face of the second piston 122 abuts against the bottom of the hole portion 121e (the left portion in FIG. 2). The first valve body 151 is not in contact with the protrusion 161c of the protrusion member 161, and is biased to the right by the third biasing member 143 to be in a closed state. The second valve body 152 is biased to the left by the fourth biasing member 144 to be in a closed state.

[0073] Here, in the hydraulic control unit 15, as described above, when antilock brake control, anti-skid control, or the like is executed, the pump 36 is driven. In the state of FIG. 2, when the pump 36 is driven, brake fluid flows into the damping device 100 through the first opening PO1, and the pressure in the space to the left of the first piston 121 in the first fluid chamber S! increases. As a result, first, the first piston 121 moves to the right.

[0074] In the following, an example will be described in which the second piston 122 starts to move relatively to the first piston 121 after the first piston 121 starts to move. However, the timing at which the first piston 121 starts to move and the timing at which the second piston 122 starts to move relatively to the first piston 121 may be simultaneous, or the first piston 121 may start to move after the second piston 122 starts to move relatively to the first piston 121. [0075] Fig. 3 is a diagram showing a state in which the first piston 121 in the damping device 100 has moved to the right compared to the state in Fig. 2. In the state in Fig. 3, pressure is stored in the space to the left of the first piston 121 in the first liquid chamber S1. The first piston 121 is pressed to the right by the pressure in the space to the left of the first piston 121 in the first liquid chamber S1, and the first piston 121 has moved to the right compared to the state in Fig. 2. When the first piston 121 moves to the right, the first biasing member 141 expands and contracts, and as a result, it contracts. As a result, the force acting on the first piston 121 is absorbed by the first biasing member 141. In this manner, the first biasing member 141 expands and contracts as the first piston 121 moves, thereby attenuating the pressure pulsation.

[0076] In the state shown in Fig. 3, brake fluid is sent from the space on the left side of the second piston 122 to the space on the right side of the second piston 122 through the third through hole 122d of the second piston 122. In this way, even when the tip of the protrusion 161c of the protrusion member 161 is not in contact with the first valve body 151 and the first valve body 151 is in the closed state, the brake fluid can pass through the third through hole 122d and flow from the space on the left side of the second piston 122 to the space on the right side of the second piston 122. Here, the inner diameter of the third through hole 122d is small, and a large resistance is applied to the brake fluid flowing through the third through hole 122d. Therefore, the pressure pulsation is also attenuated by the brake fluid flowing through the third through hole 122d.

[0077] In the state shown in Fig. 3, brake fluid passes through the second through hole 161e of the protruding member 161 from the space to the left of the protruding member 161 to the space to the right of the protruding member 161. Here, the inner diameter of the second through hole 161e is small, and a large resistance is applied to the brake fluid flowing through the second through hole 161e. Therefore, the pressure pulsation is attenuated by the brake fluid flowing through the second through hole 161e.

[0078] Fig. 4 is a diagram showing a state in which the second piston 122 in the damping device 100 has moved to the right compared to the state in Fig. 3. In the state in Fig. 4, the second piston 122 is pressed to the right by the pressure in the space to the left of the second piston 122 in the first fluid chamber S1, and moves to the right relatively to the first piston 121. When the second piston 122 moves to the right relatively to the first piston 121, the second biasing member 142 expands and contracts, and as a result, it contracts. As a result, the force acting on the second piston 122 is absorbed by the second biasing member 142. In this way, the second biasing member 142 expands and contracts as the second piston 122 moves, thereby attenuating the pressure pulsation.

[0079] When the second piston 122 moves to the right relative to the first piston 121, the first piston 121 also actually moves to the right. Therefore, the pressure pulsation is attenuated not only by the absorption of force by the second biasing member 142, but also by the absorption of force by the first biasing member 141.

[0080] Fig. 5 is a diagram showing a state in which the first piston 121 and the second piston 122 in the damping device 100 have moved to the right compared to the state in Fig. 4. In the state in Fig. 5, compared to the state in Fig. 4, the first piston 121 has moved further to the right, and the second piston 122 has moved further to the right relative to the first piston 121. In the state in Fig. 5, the tip of the protrusion 161c of the protrusion member 161 abuts against the first valve body 151, and the relative position of the first valve body 151 to the first piston 121 is maintained. As a result, the first valve body 151 is separated from the first through hole 122c and enters an open state, and brake fluid flows through the first through hole 122c from the left side to the right side.

[0081] Furthermore, in the state shown in FIG. 5, as a result of the increase in pressure in the communication hole 113c, the second valve body 152 moves to the right. As a result, the second valve body 152 is moved toward the left side. As a result, the second valve body 152 is separated from the communication hole 113c and is in an open state, and the brake fluid flows through the communication hole 113c from the left side to the right side. Then, the brake fluid that has passed through the communication hole 113c flows out from the second fluid chamber S2 via the second opening PO2.

[0082] As shown in Fig. 5, when the second valve body 152 is in an open state, the second valve body 152 can come into contact with the second cover 112. In the example of Fig. 5, the first shaft portion 152b and the second shaft portion 152c of the second valve body 152 move along the central axis of the housing 101. As described above, the second cover 112 is formed with the second opening PO2 as well as the through hole 112a. Here, the inner diameter of the through hole 112a is larger than the outer diameter of the second shaft portion 152c and smaller than the outer diameter of the first shaft portion 152b. Therefore, the step surface between the first shaft portion 152 b and the second shaft portion 152 c of the second valve body 152 can abut against the second cover 112. As a result, even when the second valve body 152 is in the open state, the second valve body 152 does not vibrate, and the posture of the second valve body 152 is stabilized.

[0083] As described above, when the brake fluid flows out from the second fluid chamber S2 through the second opening PO2, the pressure in the damping device 100 drops. As a result, the first piston 121 located on the right side in the damping device 100 moves to the left and returns to the state shown in FIG. 2. Thereafter, the brake fluid flows into the damping device 100 through the first opening PO!, and the operation described with reference to FIGS. 2 to 5 is repeated. Here, as described above, the left side of the first piston 121 is provided with the buffer member 171 that can come into contact with the first cover 111. Therefore, when the first piston 121 moves to the right and then returns to the left, the impact caused by the collision between the first piston 121 and the first cover 111 can be mitigated.

[ 0 0 8 4 ]

<Effects of the Damping Device> The effects of the damping device 1 according to the embodiment of the present invention will be described.

[0085] The damping device 100 includes a first fluid chamber S! communicating with an inlet port P1 via a first opening PO1, a second fluid chamber S2 communicating with the first fluid chamber S! via a communication hole 113c and communicating with an outlet port P2 via a second opening PO2, a first piston 121 slidably provided in the first fluid chamber S1, a first biasing member 141 biasing the first piston 121 toward the first opening PO1 side, a hole 121e formed in the first piston 121 so as to be recessed from the second opening PO2 side toward the first opening PO1 side, and a hole 121f formed in the first piston 121. a second piston 122 slidably provided in the first opening PO1 side of the valve member 142; a first through hole 122c provided in the second piston 122 and penetrating from the first opening PO1 side to the second opening PO2 side; a first valve body 151 capable of opening and closing the first opening PO1 side of the first through hole 122c; a third biasing member 143 biasing the first valve body 151 toward the second opening PO2 side; and a protrusion 161c capable of being inserted into the first through hole 122c and being able to come into contact with the first valve body 151. a protrusion member 161 provided in the second fluid chamber S2 on the second opening PO2 side with respect to the second piston 122 of the first piston 121 and moving integrally with the first piston 121; a second valve body 152 provided in the second fluid chamber S2 and capable of opening and closing the second opening PO2 side of the communicating hole 113c; and a fourth biasing member 144 biasing the second valve body 152 toward the first opening PO1 side.

[0086] As a result, when the pump 36 is driven, pressure is first stored in the space of the first liquid chamber S1 to the left of the first piston 121. During this time, the first urging member 141 gradually contracts as the first piston 121 moves, absorbing the energy of the pressure rise. Furthermore, the second urging member 142 gradually contracts as the second piston 122 moves relative to the first piston 121, absorbing the energy of the pressure rise. As a result, the rate of increase in pressure on the second opening PO2 side of the first piston 121 becomes slower than the rate of increase in pressure on the first opening PO! side of the first piston 121.

Nor.

[0096] The configuration of the damping device 100 has been described above with reference to Fig. 2. However, damping devices according to the present invention may include those that are modified in various ways from the example of Fig. 2.

[0097] For example, the sliding direction of the first piston 121 and the second piston 122 may be different from the axial direction of the housing 101. For example, when the central axis of the first liquid chamber S1 is not arranged coaxially with the housing 101, the sliding direction of the first piston 121 and the second piston 122 is different from the axial direction of the housing 101.

[0098] For example, the cross-sectional shape perpendicular to the sliding direction of the first liquid chamber S1, the first piston 121, and the second piston 122 does not have to be a circle. The cross-sectional shape may be, for example, an ellipse or a polygon. In this case, the circumferential direction of each of the first piston 121 and the second piston 122 is a direction along the outer circumferential edge of each of the first piston 121 and the second piston 122, and is a direction around the central axis of each of the first piston 121 and the second piston 122.

[0099] For example, the cross-sectional shape perpendicular to the axial direction of the protrusion member 161 does not have to be circular. The cross-sectional shape may be, for example, an ellipse or a polygon. Even in this case, the circumferential direction of the protrusion member 161 is the direction along the outer periphery of the protrusion member 161, and is the direction around the central axis of the protrusion member 161.

[0100] For example, the damping device according to the present invention may also include the example shown in Fig. 2 in which the second through hole 161e is omitted. When the second through hole 161e is omitted, for example, a groove extending in the axial direction may be provided on the inner circumferential surface of the hole portion 121e, and the brake fluid may be able to flow from the left side to the right side of the protruding member 161 through the groove.

[0101] For example, the damping device according to the present invention may also include one in which the third through hole 122d is omitted from the example of Fig. 2. When the third through hole 122d is omitted, for example, a groove extending in the axial direction may be provided on the inner circumferential surface of the hole portion 121e, and the brake fluid may be able to flow from the left side to the right side of the second piston 122 through the groove.

[0102] For example, the damping device according to the present invention may also include the example of FIG. 2 in which the buffer member 171 is omitted.

[0103] For example, in the example of FIG. 2, the shape of the second valve body 152 may be changed to another shape, such as a spherical shape, and the second valve body 152 may not come into contact with the second cover 112.

2 1 Main flow path 2 2 Secondary flow path

2 3 Supply channel

3 1 In valve 3 2 Release valve 3 3 First valve 3 4 Second valve 3 5 Accumulator 3 6 Pump 3 7 Motor 1 0 0 Damping device 1 0 1 Housing 1 1 1 First cover 1 1 2 Second cover 1 1 3 Third cover 1 1 3 c Communication hole 1 1 4 Fourth cover 1 2 1 First piston 1 2 1 e Hole 1 2 2 Second piston 1 2 2 c First through hole

1 2 2 d 3rd Through Hole

1 3 1 !Sealing material

1 3 2 Second seal member

1 4 1 First biasing member 1 4 2 Second biasing member 1 4 3 Third biasing member

1 4 4 Fourth biasing member

1 5 1 First valve body

1 5 2 Second valve body

1 6 1 Protruding member 1 6 1 c Protruding part

1 6 1 e Second through hole

1 7 1 Cushioning material P 1 Inlet port

P 2 Outlet port P 〇 1 First opening P 〇 2 Second opening S 1 First fluid chamber S 2 Second fluid chamber

Claims

[Document name] Scope of claims

[Claim 1] A hydraulic control unit (15) for controlling the braking force acting on a wheel (17), comprising: a pump

A damping device (100) for damping pressure pulsation, comprising: an inlet port (P1) connected to a discharge side of a pressure vessel (36) and an outlet port (P2) communicating with the inlet port (P1); a first fluid chamber (S1) communicating with the inlet port (P1) through a first opening (PO1); a second fluid chamber (S2) communicating with the first fluid chamber (S1) through a communication hole (113c) and communicating with the outlet port (P2) through a second opening (PO2); a first piston (121) slidably provided in the first fluid chamber (S1); A first biasing member (1) biasing the

a hole portion (121e) formed in the first piston (121) so as to be recessed from the second opening (P02) side toward the first opening (P0!) side; a second piston (122) slidably provided in the hole portion (121e); and a second biasing member (122) biasing the second piston (122) toward the first opening (P01) side.

a piston (122) provided with a first opening (P01) and a second opening (122) provided with a second opening (12 ...

a first through hole (122c) penetrating to the first opening (PO2) side, and a first valve body (15) capable of opening and closing the first opening (PO1) side of the first through hole (122c).

a third biasing member (143) for biasing the first valve body (151) toward the second opening (P02); a protrusion member (161) having a protrusion portion (161c) that can be inserted into the first through hole (122c) and can come into contact with the first valve body (151), the protrusion member (161) being provided on the second opening (P02) side of the second piston (122) of the first piston (121) and moving integrally with the first piston (121); a second valve body (152) capable of opening and closing a first opening (P01) side, and a fourth biasing member (144) biasing the second valve body (152) toward the first opening (P01).

[Claim 2] The damping device according to claim 1, wherein at least one second through hole (161e) penetrating from the first opening (PO1) side to the second opening (PO2) side is formed in the protrusion member (161).

[Claim 3] The damping device according to claim 2, wherein a plurality of the second through holes (161e) are formed in the protrusion member (161), and the plurality of second through holes (161e) are disposed at equal intervals in the circumferential direction of the protrusion member (161).

[Claim 4] The second piston (122) has a first opening (P01) and a second opening (P02).

2) and at least one third through hole (122d) different from the first through hole (122c).

[Claim 5] A plurality of the third through holes (122d) are formed in the second piston (122), and the third through holes (122d) are arranged at equal intervals in a circumferential direction of the second piston (122). The damping device according to claim 4, wherein the damping device is disposed on a substrate.

[Claim 6] A first cover (111) is provided to cover the first fluid chamber (S1) from the first opening (PO1) side, and a first cover (111) is provided on the first opening (PO1) side of the first piston (121).

The damping device according to claim 1, further comprising a buffer member (171) capable of abutting against the bearing member (111).

[Claim 7] The damping device according to claim 1, further comprising a second cover (112) covering the second fluid chamber (S2) from the second opening (PO2) side, and the second valve body (152) is capable of abutting against the second cover (112).

[Claim 8] A hydraulic control unit comprising the damping device (100) according to any one of claims 1 to 7.

[Claim 9] A brake system comprising the hydraulic control unit (15) according to claim 8.