Damping device, hydraulic control unit, and brake system

Abstract

The pressure pulsation of the hydraulic control unit is attenuated. The present invention is provided with: a first liquid chamber that communicates with an inlet port via a first opening; a second liquid chamber communicating with the first liquid chamber via a communication hole and communicating with the outlet port via a second opening; a first piston slidably provided in the first liquid chamber; a first biasing member that biases the first piston toward the first opening side; a hole formed in the first piston so as to be recessed from the second opening side toward the first opening side; a second piston slidably provided in the hole; a second biasing member that biases the second piston toward the first opening side; a first through-hole provided in the second piston and penetrating from the first opening side to the second opening side; a first valve body capable of opening and closing a first opening side of the first through hole; a third biasing member that biases the first valve body toward the second opening side; a protruding member that has a protruding portion that can be inserted through the first through-hole and that can come into contact with the first valve body, is provided on the second opening side of the first piston with respect to the second piston, and moves integrally with the first piston; a second valve body provided in the second liquid chamber and capable of opening and closing a second opening side of the communication hole; and a fourth biasing member that biases the second valve body toward the first opening side. The present invention is provided with: a sliding member that is disposed in the recess of the protruding member, slides in the hole in response to the pressure liquid from the input port side, and has an internal passage; and a fifth biasing member that biases the sliding member toward the first opening side.

Description

TECHNICAL FIELD

[0001] The present application relates to an attenuation device, a hydraulic control unit, and a brake system. BACKGROUND

[0002] In the related art vehicle, a hydraulic control unit is provided in order to control a brake force generated at a wheel. For example, as disclosed in Patent Literature 1, a plurality of valves and a pump are provided in a flow path in the hydraulic control unit. In such a hydraulic control unit, in the antilock brake control or the anti-skid control, or the like, a control is performed in which the opening and closing states of the valves are set to specific states and the pump is driven.

[0003] PRIOR ART DOCUMENTS PATENT LITERATURE Patent Literature 1: Japanese Patent Application Publication No. 2010-052519 SUMMARY

[0004] PROBLEMS TO BE SOLVED BY THE INVENTION Incidentally, in the hydraulic control unit, as the pump, a plunger pump that performs a reciprocating motion is mainly used. Therefore, the pressure feeding of the brake fluid by the pump is performed intermittently. Due to this, if the pump is driven, a phenomenon in which a hydraulic pressure pulsation of the brake fluid occurs in the flow path in the hydraulic control unit, that is, a pressure pulsation occurs. There are cases in which a sound generated by such a pressure pulsation is perceived as a noise by an occupant of the vehicle, and this can become a major factor that impairs the comfort. Therefore, from the viewpoint of improving the comfort, it is desirable to appropriately attenuate the pressure pulsation of the hydraulic control unit.

[0005] Therefore, the present application is made in view of such a problem, and an object thereof is to provide an attenuation device, a hydraulic control unit, and a brake system that can attenuate a pressure pulsation of a hydraulic control unit.

[0006] MEANS FOR SOLVING THE PROBLEMS To solve the above problem, the damping device is provided in a hydraulic control unit that controls a braking force generated at a wheel, has an inlet port connected to an ejection side of a pump and an outlet port communicated with the inlet port, and attenuates pressure pulsation; provided are: a first liquid chamber communicated with the inlet port via a first opening; a second liquid chamber communicated with the first liquid chamber via a communication hole and communicated with the outlet port via a second opening; a first piston slidably provided in the first liquid chamber; a first force applying member applying a force to the first piston toward the first opening side; a hole portion recessed in the first piston from the second opening side toward the first opening side; a second piston slidably provided in the hole portion; a second force applying member applying a force to the second piston toward the first opening side; a first through hole provided in the second piston and 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 force applying member applying a force to the first valve body toward the second opening side; a protrusion member having a protrusion capable of being inserted in the first through hole and capable of abutting against the first valve body, provided in the first piston on the second opening side 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 force applying member applying a force to the second valve body toward the first opening side; and provided are: a sliding member disposed in a recess of the protrusion member, sliding in the recess according to pressure fluid from the inlet port side, and having an internal passage; and a fifth force applying member applying a force to the sliding member toward the first opening side.

[0007] To solve the above problem, the hydraulic control unit is provided with the above-described damping device.

[0008] To solve the above problem, the braking system is provided with the above-described hydraulic control unit.

[0009] Effects of Invention According to the present application, pressure pulsation of a hydraulic control unit can be attenuated. BRIEF DESCRIPTION OF DRAWINGS

[0010] Figure 1 is a schematic view showing a schematic configuration of a braking system relating to an embodiment of the present application.

[0011] Figure 2 is a sectional view showing a schematic configuration of a damping device relating to an embodiment of the present application, showing the damping device in a non-acting state.

[0012] Figure 3 is a sectional view showing a schematic configuration of a damping device relating to an embodiment of the present application, showing the damping device in a state of being acted on (before pressure release).

[0013] Figure 4 is a sectional view showing a schematic configuration of a damping device relating to an embodiment of the present application, showing the damping device in a state of being acted on (after pressure release). DETAILED DESCRIPTION

[0014] Hereinafter, a preferred embodiment of the present application will be described in detail with reference to the accompanying drawings. The dimensions, materials, other specific numerical values and the like shown in the embodiment are merely examples for facilitating understanding of the application, and do not limit the present application unless otherwise specified. In addition, in the present specification and the drawings, elements having substantially the same function and structure are designated by the same reference numerals, and repeated description is omitted, and elements not directly related to the present application are omitted from the drawings. Figure 1

[0015] In the present embodiment, a vehicle having four wheels 17 is exemplified as a vehicle, but the vehicle to which the present application is applied is not limited to the vehicle having four wheels 17, and for example, can be a vehicle having one, two, three or more wheels 17, or a vehicle having five or more wheels 17.

[0016] <Structure of brake system> Reference Signs Figure 1 The structure of the brake system 1 according to the embodiment of the present application will be described.

[0017] Figure 1 is a schematic view showing the outline structure of the brake system 1. The brake system 1 is mounted on a vehicle, and is a system for controlling the braking force generated in the vehicle. As shown in Figure 1 , the brake system 1 is provided with a brake pedal 11, a booster 12, a master cylinder 13, a reservoir 14, a hydraulic control unit 15, a brake device 16, and wheels 17.

[0018] The brake system 1 is mounted on a vehicle having four wheels 17, and brakes each wheel 17 by means of the brake device 16 provided in each wheel 17. Further, the braking force generated in each wheel 17 is controlled by the hydraulic control unit 15. In Figure 1 , in order to facilitate understanding, only the portion of the brake system 1 associated with one of the front and rear wheels is shown, and the illustration of the portion associated with the other of the front and rear wheels is omitted.

[0019] In addition, the number of wheels 17 whose braking force is controlled by the hydraulic control unit according to the present application can be other than four. For example, the number of wheels 17 whose braking force is controlled by the hydraulic control unit 15 can be two. In this case, the brake system 1 can be mounted on a vehicle having two wheels 17.

[0020] ​The brake pedal 11 is used in a brake operation by the driver. In the brake operation, the brake pedal 11 is depressed by the driver. The booster 12 is connected to the brake pedal 11, and amplifies the depression force of the brake pedal 11. The master cylinder 13 is connected to the booster 12, and has a piston that reciprocates in conjunction with the brake pedal 11 to generate hydraulic pressure corresponding to the operation amount of the brake operation. The reservoir 14 is attached to the master cylinder 13, and stores brake fluid.

[0021] The hydraulic control unit 15 has a base 15a that forms a flow path of brake fluid. The base 15a of the hydraulic control unit 15 is connected to the master cylinder 13 and each of the brake devices 16. The flow path of brake fluid of the base 15a of the hydraulic control unit 15 is connected to the wheel cylinders of the brake devices 16. The wheels 17 generate braking force corresponding to the hydraulic pressure of brake fluid in the wheel cylinders of the brake devices 16.

[0022] The base 15a of the hydraulic control unit 15 has a main flow path 21, a sub flow path 22, and a supply flow path 23 formed as flow paths of brake fluid. The main flow path 21 circulates brake fluid of the master cylinder 13 to the wheel cylinders of the brake devices 16. The sub flow path 22 drains brake fluid of the wheel cylinders of the brake devices 16. The supply flow path 23 supplies brake fluid of the master cylinder 13 to the sub flow path 22.

[0023] Further, the base 15a of the hydraulic control unit 15 has a charge 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 provided as components for controlling the braking force generated at each of the wheels 17.

[0024] In addition, the structure of the hydraulic control unit of the present application can have only the pump 36, and can be different from the structure of the hydraulic control unit 15 shown in Figure 1 For example, the structure of the hydraulic control unit 15 shown in Figure 1 The structure of the supply flow path 23, the first valve 33, and the second valve 34 is also included in the hydraulic control unit of the present application.

[0025] The main flow path 21 communicates the master cylinder 13 with the wheel cylinders of the brake devices 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 21b branch from the first main flow path 21a and are connected to each of the brake devices 16. The first valve 33 is provided in the first main flow path 21a. The charge valve 31 is provided in the second main flow path 21b.

[0026] The sub flow path 22 connects the side of the main flow path 21 closer to the brake device 16 than the filling valve 31 to the side of the main flow path 21 closer to the master cylinder 13 than the first valve 33 and closer to the brake device 16 than the first valve 33. The sub flow path 22 includes two first sub flow paths 22a and a second sub flow path 22b. Each first sub flow path 22a is connected to the side of the main flow path 21 closer to the brake device 16 than the filling valve 31. The second sub flow path 22b connects the confluence of the two first sub flow paths 22a to the side of the main flow path 21 closer to the master cylinder 13 than the filling valve 31 and closer to the brake device 16 than the first valve 33. A release valve 32 is provided in the first sub flow path 22a. In the second sub flow path 22b, a reservoir 35 and a pump 36 are provided in this order from the side of the first sub flow path 22a.

[0027] The pump 36 is driven by a motor 37 to suck brake fluid from the side of the first sub flow path 22a and eject it toward the side of the main flow path 21. The pump 36 is a plunger pump that performs reciprocating motion. Specifically, the plunger of the pump 36 performs reciprocating motion by being intermittently pushed by an eccentric cam provided on the output shaft of the motor 37. Thus, pressure feeding of brake fluid by the pump 36 is performed.

[0028] The supply flow path 23 connects the side of the main flow path 21 closer to the master cylinder 13 than the first valve 33 to 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.

[0029] The filling valve 31 is, for example, an electromagnetic valve that is opened in a non-energized state and closed in an energized state. The release valve 32 is, for example, an electromagnetic valve that is closed in a non-energized state and opened in an energized state. The first valve 33 is, for example, an electromagnetic valve that is opened in a non-energized state and closed in an energized state. The second valve 34 is, for example, an electromagnetic valve that is closed in a non-energized state and opened in an energized state. By controlling the operation of these valves and the motor 37, the brake force generated at each wheel 17 is controlled.

[0030] For example, in normal times when the antilock brake control or the anti-skid control or the like described later is not executed, the filling valve 31 is opened, the release valve 32 is closed, the first valve 33 is opened, and the second valve 34 is closed. Thus, a state is achieved in which brake fluid flows from the master cylinder 13 to the wheel cylinder of the brake device 16 not via the sub flow path 22 and the supply flow path 23 but only via the main flow path 21. In this state, if the brake pedal 11 is depressed, the piston of the master cylinder 13 is pushed in, the hydraulic pressure of the brake fluid of the wheel cylinder increases, and a brake force is imparted to the wheel 17.

[0031] The antilock brake control is control for avoiding lock of the wheels 17. For example, if the antilock brake control is executed, first, the charge valve 31 is closed, the release valve 32 is opened, the 1st valve 33 is opened, and the 2nd valve 34 is closed. Thereby, the flow of the brake fluid between the main flow path 21 and the wheel cylinder of the brake device 16 is stopped, and a state in which the brake fluid can flow from the wheel cylinder to the sub flow path 22 is made. Therefore, the brake fluid flows from the wheel cylinder to the accumulator 35, the hydraulic pressure of the brake fluid of the wheel cylinder is reduced, and the brake force applied to the wheel 17 is reduced. The brake fluid flowing into the accumulator 35 is sent back to the main flow path 21 via the sub flow path 22 by the pump 36 being driven.

[0032] Then, by both the charge valve 31 and the release valve 32 being closed from the above state, the flow of the brake fluid between the main flow path 21 and the sub flow path 22 and the wheel cylinder is stopped, the hydraulic pressure of the brake fluid of the wheel cylinder is maintained, and the brake force applied to the wheel 17 is maintained. Then, by the charge valve 31 being opened and the release valve 32 being closed, the flow of the brake fluid between the main flow path 21 and the wheel cylinder is started again, the hydraulic pressure of the brake fluid of the wheel cylinder is increased, and the brake force applied to the wheel 17 is increased.

[0033] The anti-skid control is control for stabilizing the behavior of the vehicle. In the anti-skid control, the driving force and the brake force of the vehicle are appropriately controlled. For example, in the execution of the anti-skid control, when the vehicle is braked without depending on the brake operation, the charge valve 31 is opened, the release valve 32 is closed, the 1st valve 33 is closed, and the 2nd valve 34 is opened. Thereby, a state in which the brake fluid flows from the master cylinder 13 to the wheel cylinder of the brake device 16 via the supply flow path 23 and the sub flow path 22 is made. By the pump 36 being driven in this state, the hydraulic pressure of the brake fluid of the wheel cylinder is increased, and the brake force that brakes the wheel 17 is generated.

[0034] As described above, in the hydraulic control unit 15, control that drives the pump 36 is performed. If the pump 36 is driven, a phenomenon in which the hydraulic pressure of the brake fluid pulsates in the flow path within the hydraulic control unit 15, that is, pressure pulsation occurs. There is a case in which the sound generated by such pressure pulsation is perceived as noise by the occupant of the vehicle, and can become a major factor that impairs comfort. Therefore, in the hydraulic control unit 15, the attenuation device 100 that attenuates the pressure pulsation is provided.

[0035] The attenuation device 100 is provided in the sub flow path 22, specifically, the 2nd sub flow path 22b, on the downstream side from the pump 36. The attenuation device 100 has an inlet port P1 and an outlet port P2. The inlet port P1 is connected to the discharge side of the pump 36. The inlet port P1 communicates with the outlet port P2. Therefore, the brake fluid discharged from the pump 36 flows into the attenuation device 100 via the inlet port P1, and after passing through the attenuation device 100, flows out of the attenuation device 100 via the outlet port P2.

[0036] <Structure of the attenuation device> Reference Figure 2 The structure of the attenuation device 100 according to the embodiment of the present application will be described.

[0037] Figure 2 is a cross-sectional view showing the schematic structure of the attenuation device 100. However, Figure 2 The attenuation device 100 shown in the drawing is merely an example of the attenuation device according to the present application, and the following Figure 2 will be described with various modified structures of the example shown in the drawing included in the attenuation device according to the present application.

[0038] In Figure 2 and the following Figures 3-4 , the axial direction of the housing 101 is taken as the left-right direction, and the attenuation device 100 is shown in such a manner that the first opening P01 connected to the inlet port P1 is located on the left side in the axial direction, and the second opening P02 connected to the outlet port P2 is located on the right side in the axial direction. Hereinafter, the axial direction of the housing 101, i.e., the left-right direction, will be simply referred to as the axial direction. The first opening P01 side refers to the side toward the first opening P01 in the axial direction with the second opening P02 as a reference (the left side in the drawing) or the upstream side in the flow direction of the brake fluid from the first opening P01 toward the second opening P02. The second opening P02 side refers to the side toward the second opening P02 in the axial direction with the first opening P01 as a reference (the right side in the drawing) or the downstream side in the flow direction of the brake fluid from the first opening P01 toward the second opening P02. Figures 2-4 Figures 2-4

[0039] As shown in Figure 2 , the attenuation device 100 includes the housing 101, the first cover 111, the second cover 112, the third cover 113, the fourth cover 114, the first piston 121, the second piston 122, the first seal member 131, the second seal member 132, the first urging member 141, the second urging member 142, the third urging member 143, the fourth urging member 144, the fifth urging member 300b, the first valve body 151, the second valve body 152, the protrusion member 161, and the sliding member 300.

[0040] ​​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. In the housing 101, an internal space is formed in a manner that penetrates from the left end surface to the right end surface. The internal space of the housing 101 includes a first hole portion 101a, a second hole portion 101b, and a third hole portion 101c. Each of the first hole portion 101a, the second hole portion 101b, and the third hole portion 101c has a cylindrical shape and is disposed coaxially with the central axis of the housing 101. The first hole portion 101a, the second hole portion 101b, and the third hole portion 101c are continuous in this order from the left side. Further, the diameters of the respective hole portions are shaped as third hole portion 101c < second hole portion 101b < first hole portion 101a.

[0041] In the first hole portion 101a and the second hole portion 101b, the first cover 111 is fitted. The first cover 111 has a substantially circular plate shape. The left end portion of the outer peripheral surface of the first cover 111 is expanded in the radial direction. The portion of the first cover 111 that is expanded in the radial direction is fitted in the first hole portion 101a, and the portion of the first cover 111 that is not expanded in the radial direction is fitted in the second hole portion 101b.

[0042] Further, the first cover 111 has one or a plurality of slits 111a that are connected to the first opening PO1.

[0043] In the third hole portion 101c, the third cover 113 is fitted. 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 cylindrical shapes and are disposed 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 in the right end portion of the third hole portion 101c. The outer peripheral surface of the second cylindrical portion 113b is radially separated from the inner peripheral surface of the second hole portion 101b.

[0044] Further, the right end surface of the first cylindrical portion 113a has one or a plurality of slits 113d that are connected to the second opening PO2.

[0045] A first opening PO1 is formed between the first cover 111 and the third cover 113 in the peripheral wall portion of the case 101. The first opening PO1 communicates with the second hole portion 101b. The first liquid chamber S1 is demarcated by the right side face of the first cover 111, the left side face of the third cover 113, and the inner peripheral face of the second hole portion 101b of the case 101. That is, the first cover 111 covers the first liquid chamber S1 from the left side. In other words, the right side face of the first cover 111 constitutes the left side wall face of the first liquid chamber S1. The third cover 113 covers the first liquid chamber S1 from the right side. In other words, the left side face of the third cover 113 constitutes the right side wall face of the first liquid chamber S1. The first liquid chamber S1 has a substantially cylindrical shape. The first liquid chamber S1 communicates with the inlet port P1 via the first opening PO1.

[0046] The second liquid chamber S2 is demarcated by the inner peripheral face of the third cover 113. The left end portion in the inner peripheral face of the third cover 113 is tapered inward in the radial direction. Thus, a communication hole 113c is formed in the center of the left end portion of the third cover 113. The second liquid chamber S2 communicates with the first liquid chamber S1 via the communication hole 113c.

[0047] The second cover 112 is fitted in the right end portion in the inner peripheral face of the third cover 113. The second cover 112 is formed in a substantially circular plate shape having a second opening PO2. The second opening PO2 is disposed on the radially outer side than the center of the second cover 112. In the example shown in FIG. 1, the second cover 112 is disposed on the radially outer side than the third cover 113. In other words, the second cover 112 is disposed on the radially outer side than the third cover 113 in the axial direction. The second cover 112 is disposed on the radially outer side than the third cover 113 in the axial direction. Figure 2 In the example shown in FIG. 1, the number of the second openings PO2 is plural. However, the number of the second openings PO2 can be one.

[0048] Further, the right side end face of the first cylindrical portion 113a is fitted in the fifth cover 304, and the second openings PO2 are connected to the outlet port P2 connected to the first main flow passage 21a.

[0049] The right end portion in the inner peripheral face of the third cover 113 is expanded in diameter. The second cover 112 is fitted in the expanded portion in the inner peripheral face of the third cover 113. Thus, the second liquid chamber S2 is demarcated by the left side face of the second cover 112. That is, the second cover 112 covers the second liquid chamber S2 from the right side. In other words, the left side face of the second cover 112 constitutes the right side wall face of the second liquid chamber S2. The second liquid chamber S2 communicates with the outlet port P2 via the second openings PO2.

[0050] The first piston 121 is housed in the second hole portion 101b. The first piston 121 has a substantially cylindrical shape. The first piston 121 is disposed coaxially with the central axis of the second hole portion 101b. The first piston 121 has a cylindrical portion 121a in a cylindrical shape.

[0051] The outer peripheral surface of the cylindrical portion 121a is able to slide with respect to the inner peripheral surface of the second hole portion 101b. Therefore, the first piston 121 is provided so as to be able to slide in the axial direction in the first liquid chamber S1. In addition, the first liquid chamber S1 is connected to the first opening PO1 via the gap between the left side outer peripheral surface of the first piston 121 and the second hole portion 101b, and the slit 111a.

[0052] Further, in the outer peripheral surface of the cylindrical portion 121a, an annular groove 121c is formed. The annular groove 121c extends in the circumferential direction of the first piston 121. In the annular groove 121c, the first seal member 131 is fitted. The first seal member 131 is, for example, an O-ring. The first seal member 131 is pressed against the inner peripheral surface of the second hole portion 101b. Thereby, the gap between the outer peripheral surface of the second cylindrical portion 121b and the inner peripheral surface of the second hole portion 101b is liquid-tightly sealed. In Figure 2 In the example, two annular grooves 121c are arranged at intervals in the axial direction, and the first seal member 131 is fitted in each of the annular grooves 121c. However, the number of annular grooves 121c can be one or more than three.

[0053] Further, in the cylindrical portion 121a, a small-diameter hole 121b that communicates between the first liquid chamber S1 and the second liquid chamber S2 is formed. It is used to prevent the sharp sliding of the first piston 121 and the damage accompanying it in the case where high-pressure liquid temporarily flows into the first liquid chamber S1. In addition, the small-diameter hole 121b can be formed one or more.

[0054] The first piston 121 is urged to the left side by the first urging member 141. The first urging member 141 is, for example, an elastic member such as a spring. The first urging member 141 is arranged between the first piston 121 and the third cover 113. One end (the left end in Figure 2 ) of the first urging member 141 abuts against the right end surface of the first piston 121. The other end (the right end in Figure 2 ) of the first urging member 141 abuts against the surface on the left side of the first cylindrical portion 113a of the third cover 113. The extension direction of the first urging member 141 becomes the left-right direction. The first urging member 141 becomes a state of contraction with respect to the natural length.

[0055] In the left side of the first piston 121, a hole portion 121d is formed. The hole portion 121d is a portion that is recessed from the left side toward the right side in the first piston 121. The hole portion 121d is recessed from the left end surface of the first piston 121 toward the right side. The hole portion 121d has a cylindrical shape and is arranged coaxially with the central axis of the case 101. However, the hole portion 121d can not be arranged coaxially with the central axis of the case 101.

[0056] On the right side of the first piston 121, a hole portion 121e is formed. The hole portion 121e is a portion recessed from the right side toward the left side in the first piston 121. The hole portion 121e is recessed from the right end surface of the first piston 121 toward the left side. The hole portion 121e has a cylindrical shape and is disposed coaxially with the central axis of the housing 101. However, the hole portion 121e can not be disposed coaxially with the central axis of the housing 101.

[0057] The hole portion 121d and the hole portion 121e communicate with each other. Therefore, the hole portion 121d and the hole portion 121e pass through the first piston 121 from the left side to the right side. The hole portion 121d and the hole portion 121e are continuous in this order from the left side and are disposed coaxially with each other. The inner diameter of the hole portion 121d is smaller than the inner diameter of the hole portion 121e.

[0058] The second piston 122 is housed in the hole portion 121e. The second piston 122 has a substantially cylindrical shape. The second piston 122 is disposed coaxially with the central axis of the hole portion 121e. The outer peripheral surface of the second piston 122 is slidable with respect to the inner peripheral surface of the hole portion 121e. Therefore, the second piston 122 is disposed so as to be slidable in the axial direction in the hole portion 121e.

[0059] On the outer peripheral surface of the second piston 122, an annular groove 122a is formed. The annular groove 122a extends in the circumferential direction of the second piston 122. In the annular groove 122a, a second sealing member 132 is fitted. The second sealing member 132 is, for example, an O-ring. The second sealing member 132 is pressed against the inner peripheral surface of the hole portion 121e. Thereby, the gap between the outer peripheral surface of the second piston 122 and the inner peripheral surface of the hole portion 121e is liquid-tightly sealed.

[0060] The second piston 122 is urged to the left side by a second urging member 142. The second urging member 142 is, for example, an elastic member such as a spring. As described later, a protruding member 161 is fitted in the right end portion of the inner peripheral surface of the hole portion 121e. The second urging member 142 is disposed between the second piston 122 and the protruding member 161. One end (left end) of the second urging member 142 abuts against the surface on the right side of the second piston 122. Further, the other end (right end) of the second urging member 142 abuts against the recessed portion bottom surface 161g formed in the front end portion 161f of the protruding member 161 described later. The extension direction of the second urging member 142 becomes the left-right direction. The second urging member 142 becomes a state of contraction with respect to the natural length. Figure 2 Figure 2

[0061] ​​On the left side of the 2nd piston 122, a hole portion 122b is formed. The hole portion 122b is a portion recessed from the left side toward the right side in the 2nd piston 122. The hole portion 122b is recessed from the left end surface of the 2nd piston 122 toward the right side. The hole portion 122b has a substantially cylindrical shape, and is disposed coaxially with the central axis of the hole portion 121e. However, the hole portion 122b can also be disposed non-coaxially with the central axis of the hole portion 121e.

[0062] On the left end portion in the inner peripheral surface of the hole portion 122b, the 4th cover 114 is fitted. The 4th cover 114 is formed in a circular plate shape having a through-hole 114a in the center. The through-hole 114a penetrates the 4th cover 114 from the left side to the right side. The left end portion of the inner peripheral surface of the hole portion 122b is enlarged in diameter. The 4th cover 114 is fitted in the portion of the inner peripheral surface of the hole portion 122b that is enlarged in diameter. The space in the 1st fluid chamber S1 that is to the left of the 2nd piston 122 communicates with the hole portion 122b via the through-hole 114a of the 4th cover 114.

[0063] In the 2nd piston 122, a 1st through-hole 122c that penetrates from a portion of the bottom of the hole portion 122b to the right of the 2nd piston 122 (to the right end surface of the 2nd piston 122) is provided. The 1st through-hole 122c penetrates the 2nd piston 122 from the left side to the right side. The hole portion 122b and the 1st through-hole 122c are continuous in this order from the left side, and are disposed coaxially with each other. The inner diameter of the 1st through-hole 122c is smaller than the inner diameter of the hole portion 122b. Figure 2

[0064] The 1st valve body 151 is disposed in the hole portion 122b, and is capable of opening and closing the left side of the 1st through-hole 122c. In an open state in which the 1st valve body 151 does not block the 1st through-hole 122c, brake fluid is capable of flowing through the 1st through-hole 122c. This state corresponds to an open state of the 1st valve body 151 and an open state of the 1st through-hole 122c. In a closed state in which the 1st valve body 151 blocks the 1st through-hole 122c, brake fluid is not capable of flowing through the 1st through-hole 122c. This state corresponds to a closed state of the 1st valve body 151 and a closed state of the 1st through-hole 122c.

[0065] The 1st valve body 151 has, for example, a spherical shape. However, the shape of the 1st valve body 151 can also be a shape other than a spherical shape. The 3rd urging member 143 is, for example, an elastic member such as a spring. The 3rd urging member 143 is disposed between the 4th cover 114 and the 1st valve body 151. The direction in which the 3rd urging member 143 is stretched and contracted is the left-right direction. The 3rd urging member 143 is in a state of being naturally contracted. Therefore, the 1st valve body 151 is urged to the right side by the 3rd urging member 143.

[0066] ​Further, in the first cylindrical portion 161a of the protrusion member 161, a bottomed recess 161d is formed in which the slide member 300 is fitted. The fifth urging member 300b is, for example, an elastic member such as a spring. The fifth urging member 300b is disposed between the slide member 300 and an occlusion member 303 described later. The direction of extension and contraction of the fifth urging member 300b is the left-right direction. The fifth urging member 300b is in a state of natural contraction. Therefore, the slide member 300 is urged to the left by the fifth urging member 300b.

[0067] In the left end surface of the slide member 300, a recess is formed which constitutes a damping chamber 301, the volume of which expands if the slide member 300 starts to slide to the right in a case where pressure fluid has flowed in. Further, in the slide member 300, an internal passage 300a is formed through which movement of pressure fluid between the left and right (= between the upstream side and the downstream side) of the slide member 300 is possible. Furthermore, in the first cylindrical portion 161a of the protrusion member 161, the occlusion member 303 is integrally formed, movement of pressure fluid between the left and right (= between the upstream side and the downstream side) of the occlusion member 303 being possible.

[0068] Further, the operation and effects of the slide member 300 are described later.

[0069] The protrusion member 161 is provided in order 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 disposed on the right side with respect to the second piston 122 in the first piston 121. Specifically, the protrusion member 161 is fitted to the right end portion in the inner peripheral surface of the hole portion 121e.

[0070] The protrusion member 161 has a first cylindrical portion 161a, a second cylindrical portion 161b, a protrusion portion 161c, and a front end portion 161f. The first cylindrical portion 161a, the second cylindrical portion 161b, the protrusion portion 161c, and the front end portion 161f have substantially cylindrical shapes and are disposed coaxially with each other. The first cylindrical portion 161a, the second cylindrical portion 161b, the protrusion portion 161c, and the front end portion 161f are continuous in this order from the right side. Among the outer diameters of the first cylindrical portion 161a, the second cylindrical portion 161b, the protrusion portion 161c, and the front end portion 161f, the diameters of the first cylindrical portion 161a and the front end portion 161f are substantially the same and smaller than the diameter of the second cylindrical portion 161b. Further, the diameter of the front end portion 161f is the smallest. The first cylindrical portion 161a is fitted to the right end portion in the inner peripheral surface of the hole portion 121e. The outer peripheral surface of the second cylindrical portion 161b is engaged in the radial direction with respect to the inner peripheral surface of the hole portion 121e. The protrusion portion 161c protrudes to the left side from the recess bottom surface 161g.

[0071] The protruding portion 161c is disposed coaxially with the first through-hole 122c of the second piston 122. By moving the second piston 122 from Figure 2 the position to the right relative to the first piston 121, the protruding portion 161c is inserted through the first through-hole 122c, and the front end of the protruding portion 161c can abut against the first valve body 151. By the front end of the protruding portion 161c abutting against the first valve body 151, the relative position of the first valve body 151 relative to the first piston 121 is maintained. By further moving the second piston 122 from the position to the right relative to the first piston 121 in this state, the first valve body 151 becomes the open state. In this way, the protruding portion 161c can be inserted through the first through-hole 122c, and can abut against the first valve body 151.

[0072] A recessed portion 161d is formed on the right side of the protruding member 161. The recessed portion 161d is a portion recessed from the right side toward the left side in the protruding member 161. The recessed portion 161d is recessed from the right end surface of the protruding member 161 toward the left side. The recessed portion 161d is disposed coaxially with the center axis of the hole portion 121e. However, the recessed portion 161d can not be disposed coaxially with the center axis of the hole portion 121e.

[0073] A plurality of second through-holes 161e are formed in the protruding member 161. The second through-holes 161e pass through the protruding member 161 from the left side to the right side. In Figure 2 the example, the second through-holes 161e extend to the recessed portion bottom surface 161g of the recessed portion 161d. The inner diameter of the second through-holes 161e is, for example, about 0.4 mm to 0.5 mm in diameter. In Figure 2 the example, the second through-holes 161e extend in the axial direction. However, the path of the second through-holes 161e is not particularly limited, and for example, the second through-holes 161e can extend in a direction inclined with respect to the axial direction, or can be curved or bent.

[0074] The plurality of second through-holes 161e are disposed at equal intervals in the circumferential direction of the protruding member 161. However, the disposition of the plurality of second through-holes 161e is not limited to this example. For example, the plurality of second through-holes 161e can be disposed at unequal intervals in the circumferential direction. In addition, the number of the second through-holes 161e can be one. Brake fluid can flow from the left side to the right side of the protruding member 161 through the second through-holes 161e. The second through-holes 161e are provided to improve the effect of reducing pressure pulsation. In addition, the function of the second through-holes 161e is described later.

[0075] The second valve body 152 is provided in the second liquid 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, the brake fluid is capable of flowing through the communication hole 113c. This state corresponds to an open state of the second valve body 152 and an open state of the communication hole 113c. In a closed state in which the second valve body 152 blocks the communication hole 113c, the brake fluid is not capable of flowing through the communication hole 113c. This state corresponds to a closed state of the second valve body 152 and a closed state of the communication hole 113c.

[0076] The second valve body 152 passes through the head portion 152a and the shaft portion 152b. The head portion 152a has a substantially spherical shape. Further, the head portion 152a is capable of opening and closing the communication hole 113c by being seated. The shaft portion 152b is integrally fixed to the right side of the head portion 152a. The shaft portion 152b is disposed coaxially with the central axis of the housing 101. In the center of the second cover 112, a through hole 112a is formed which communicates with the second opening PO2.

[0077] 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 extending and contracting direction of the fourth biasing member 144 is the left-right direction. The fourth biasing member 144 is in a state of being naturally elongated and contracted. Therefore, the second valve body 152 is biased to the left side by the fourth biasing member 144.

[0078] <Operation of the attenuation device> Reference will be made to Figures 2-4 the operation of the attenuation device 100 according to the embodiment of the application.

[0079] In the above-described Figure 2 , the attenuation device 100 in a normal time when the pump 36 is not driven in the hydraulic control unit 15 is shown. In this case, the first piston 121 is biased to the left side by the first biasing member 141 and is positioned at the leftmost side in the movable region. The second piston 122 is biased to the left side by the second biasing member 142 and is positioned at the leftmost side in the movable region. The left end surface of the first piston 121 abuts against the first cover 111. The left end surface of the second piston 122 abuts against the bottom portion of the hole portion 121e (the portion on the left side in Figure 2 ). Further, the sliding member 300 abuts against the bottom portion of the recess 161d (the portion on the left side in Figure 2 ).

[0080] The first valve body 151 does not abut against the protrusion portion 161c of the protrusion member 161, is biased to the right side by the third biasing member 143, and is in a closed state. The second valve body 152 is biased to the left side by the fourth biasing member 144 and is in a closed state.

[0081] Here, in the hydraulic control unit 15, the pump 36 is driven in a case where the antilock brake control or the anti-skid control or the like is executed as described above. If the pump 36 is driven in the state of Figure 2 , the brake fluid flows into the damping device 100 via the first opening POl, and the pressure of the space on the left side of the first piston 121 in the first fluid chamber SI is raised. Thus, first, the first piston 121 moves to the right side. In Figure 3 , this state is shown.

[0082] Further, the following will be described as an example in which the second piston 122 starts to move relatively to the first piston 121 after the movement of the first piston 121 is started, using Figure 3 . 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 can be simultaneous, or the first piston 121 can start to move after the second piston 122 starts to move relatively to the first piston 121.

[0083] Figure 3 is a view showing a state in which the first piston 121 moves to the right side from the state of Figure 2 . In the state of Figure 3 , the pressure is accumulated in the space on the left side of the first piston 121 in the first fluid chamber SI. Then, by the pressure of the space on the left side of the first piston 121 in the first fluid chamber SI, the first piston 121 is urged to the right side, and the first piston 121 moves to the right side from the state of Figure 2 . When the first piston 121 moves to the right side, the first urging member 141 is stretched and contracted, but as a result, the first urging member 141 is contracted. Thus, the force acting on the first piston 121 is absorbed by the first urging member 141. In this way, by the stretching and contraction of the first urging member 141 with the movement of the first piston 121, the pressure pulsation is damped.

[0084] In the state of Figure 3 , the brake fluid in the first fluid chamber SI can flow into the second fluid chamber S2 via the small-diameter hole 121b. Thus, it is possible to prevent the damage of the damping device 100 due to the sharp pressure rise of the first fluid chamber SI, and a large resistance is applied to the brake fluid flowing into the small-diameter hole 121b. Therefore, by the flow of the brake fluid in the small-diameter hole 121b, the pressure pulsation can also be damped.

[0085] Further, in the state of Figure 3 , since the first valve body 151 is maintained in the closed state, the brake fluid in the first fluid chamber SI does not flow to the protrusion member 161 side, and does not flow to the damper chamber 301 of the sliding member 300. Therefore, the sliding member 300 does not move from the bottom of the recessed portion 161d of the protrusion member 161.

[0086] If Figure 3 the state of the first liquid chamber S1 is continued, the hydraulic pressure of the first liquid chamber S1 further rises, the first piston 121 moves to the right, the first valve body 151 abuts against the protruding portion 161c, and thus, as shown in Figure 4 , the first valve body 151 becomes the open state.

[0087] Figure 4 is a view showing a state in which the second piston 122 moves to the right relative to Figure 3 , the first valve body 151 becomes the open state, and the second valve body 152 also becomes the open state.

[0088] In this view, the second piston 122 is pushed to the right by the pressure of the space in the first liquid chamber S1 that is to the left of the second piston 122, and moves to the right relative to the first piston 121. When the second piston 122 moves to the right relative to the first piston 121, the second force applying member 142 extends and contracts, but as a result, contracts. Thus, the force acting on the second piston 122 is absorbed by the second force applying member 142. In this way, by the extension and contraction of the second force applying member 142 along with the movement of the second piston 122, pressure pulsation is attenuated.

[0089] In addition, when the second piston 122 moves to the right relative to the first piston 121, the first piston 121 actually also moves to the right. Therefore, not only is pressure pulsation attenuated by the absorption of force by the second force applying member 142, but also by the absorption of force by the first force applying member 141.

[0090] Further, in this view, by the second piston 122 being pushed to the right, the first valve body 151 becomes the open state, and the pressure fluid flows into the damping chamber 301 via the second through-hole 161e, and thus, the sliding member 300 moves to the right while causing the fifth force applying member 300b to contract. At this time, pressure pulsation is also expected to be attenuated by the absorption of force by the fifth force applying member 300b.

[0091] Furthermore, the pressure fluid that has flowed into the damping chamber 301 flows into the communication hole 113c provided in the third cover 113 via the internal passage 300a provided in the sliding member 300 and the connection hole 302 provided in the blocking member 303.

[0092] The pressure of the communication hole 113c rises, and as a result, the pressure to the right of the second valve body 152 becomes greater than the pressure to the left, the fourth force applying member 144 contracts, the second valve body 152 is pushed to the right and moves while being pushed to the right, and becomes the open state by moving away from the communication hole 113c, and the brake fluid flows from the left to the right in the communication hole 113c. Then, the brake fluid after passing through the communication hole 113c flows out from the second liquid chamber S2 via the second opening PO2.

[0093] If the brake fluid flows out from the second fluid chamber S2 through the second opening PO2 as described above, the pressure in the damping device 100 decreases. Thus, the first piston 121 located on the right side in the damping device 100 moves to the left side, returning to the state described in Figure 2 Reference is made to the operation described above, and the brake fluid flows into the damping device 100 through the first opening PO1, and the operation is repeated. Figures 2-4

[0094] <Effects of the damping device> The effects of the damping device 100 according to the embodiment of the present application will be described.

[0095] The damping device 100 includes: a first fluid chamber S1 communicating with an 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 an outlet port P2 through a second opening PO2; a first piston 121 slidably provided in the first fluid chamber S1; a first force applying member 141 applying a force to the first piston 121 toward the first opening PO1; a hole portion 121e recessed in the first piston 121 from the second opening PO2 side toward the first opening PO1 side; a second piston 122 slidably provided in the hole portion 121e; a second force applying member 142 applying a force to the second piston 122 toward the first opening PO1; 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 force applying member 143 applying a force to the first valve body 151 toward the second opening PO2; a protrusion member 161 having a protrusion 161c capable of being inserted into the first through-hole 122c and capable of abutting against the first valve body 151, provided in the first piston 121 on the second opening PO2 side with respect to the second piston 122, 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 communication hole 113c; and a fourth force applying member 144 applying a force to the second valve body 152 toward the first opening PO1.

[0096] Further, the damping device 100 includes: a sliding member 300 disposed in the recessed portion 161d of the protrusion member 161, sliding in the recessed portion 161d according to the pressure fluid from the inlet port P1 side, and having an internal passage 300a; and a fifth force applying member 300b applying a force to the sliding member 300 toward the first opening PO1.

[0097] ​Thus, in a case where the pump 36 is driven, first, the pressure of the space on the left side of the first piston 121 in the first liquid chamber S1 is accumulated. Then, during this period, the energy of the pressure rise is absorbed by the gradual contraction of the first urging member 141 with the movement of the first piston 121. Further, the energy of the pressure rise is absorbed by the gradual contraction of the second urging member 142 with the relative movement of the second piston 122 with respect to the first piston 121. Thus, the speed of the pressure rise on the side of the second opening P02 with respect to the first piston 121 is slower than the speed of the pressure rise on the side of the first opening POl with respect to the first piston 121.

[0098] Further, when the pressure on the side of the first opening POl is lowered and the first piston 121 moves to the side of the first opening POl, the speed of the pressure lowering on the side of the second opening P02 with respect to the first piston 121 is slower than the speed of the pressure lowering on the side of the first opening POl with respect to the first piston 121 by the gradual elongation of the first urging member 141 and the second urging member 142. Thus, the pressure pulsation on the side of the second opening P02 can be attenuated with respect to the pressure pulsation on the side of the first opening POl.

[0099] Further, during the movement of the first piston 121 and the second piston 122 to the side of the second opening P02, the first valve body 151 can be set to the open state by the protrusion 161c of the protrusion member 161. Therefore, the brake fluid can be appropriately delivered from the first piston 121 to the side of the second opening P02. Thus, by increasing the pressure of the communication hole 113c, the second valve body 152 can be set to the open state, and the brake fluid can be appropriately delivered from the second liquid chamber S2 through the second opening P02. In this way, according to the attenuation device 100, the pressure pulsation of the hydraulic control unit 15 can be attenuated.

[0100] Further, when the sliding member 300 moves to the side of the second opening P02, the pulsation that cannot be attenuated by the first piston 121 and the second piston 122 can be attenuated by the extension and contraction of the fifth urging member 300b, and a further attenuation effect can be achieved.

[0101] Preferably, in the attenuation device 100, the protrusion member 161 is formed with at least one second through hole 161e that penetrates from the side of the first opening POl to the side of the second opening P02. Thus, by the flow of the brake fluid through the second through hole 161e, the pressure pulsation can also be attenuated.

[0102] Furthermore, although in the above-described embodiment the attenuation device 100 is provided in the hydraulic control unit 15, the attenuation device 100 can be provided in the brake fluid circuit 10. Figures 2-4However, in the case where the plurality of through-holes (not shown) are arranged at equal intervals in the circumferential direction of the protruding member 161, the flow field of the brake fluid is homogenized in the circumferential direction around the protruding member 161 by passing the brake fluid through the plurality of through-holes (not shown). Therefore, the brake fluid can flow smoothly within the attenuation device 100.

[0103] Further, although the attenuation device 100 is not disclosed in the above-described embodiment, in the case where the through-hole (not shown) is formed in the second piston 122 so as to bypass the first valve body 151, the pressure pulsation can be attenuated by passing the brake fluid through the through-hole (not shown). Figures 2-4 Further, although the attenuation device 100 is not disclosed in the above-described embodiment, in the case where the through-hole (not shown) is formed in the second piston 122 so as to bypass the first valve body 151, the pressure pulsation can be attenuated by passing the brake fluid through the through-hole (not shown).

[0104] Figures 2-4 Further, although the attenuation device 100 is not disclosed in the above-described embodiment, in the case where the through-hole (not shown) is formed in the second piston 122 so as to bypass the first valve body 151, the pressure pulsation can be attenuated by passing the brake fluid through the through-hole (not shown).

[0105] Further, in the case where the attenuation device 100 includes the first cover 111 that covers the first liquid chamber S1 from the first opening PO1 side, and the buffer member (not shown) that can abut against the first cover 111 is provided on the first opening PO1 side in the first piston 121, the impact at the time of collision between the first piston 121 and the first cover 111 can be mitigated.

[0106] Further, if the attenuation device 100 includes the second cover 112 that covers the second liquid chamber S2 from the second opening PO2 side, and the guide hole (not shown) formed in the shaft portion 152b is used to guide the sliding, the posture of the shaft portion 152b at the time of opening and closing of the second valve body 152 is stabilized. Therefore, the opening and closing operation of the second valve body 152 can be smoothed.

[0107] The above-described preferred embodiments of the present application have been described with reference to the accompanying drawings, but the present application is of course not limited to the above-described embodiments, and various modifications or alterations within the scope of the claims recited in the present application naturally belong to the technical scope of the present application. Figure 1 In the above-described embodiments, the preferred embodiments of the present application have been described with reference to the accompanying drawings, but the present application is of course not limited to the above-described embodiments, and various modifications or alterations within the scope of the claims recited in the present application naturally belong to the technical scope of the present application.

[0108] Figure 2 The structure of the attenuation device 100 has been described. However, the structure of the attenuation device 100 can be variously modified. Figure 2 Examples of the attenuation device according to the present application include the above-described attenuation device 100.

[0109] ​​For example, the sliding directions of the first and second pistons 121 and 122 can also be different from the axial direction of the housing 101. For example, in a case where the central axis of the first liquid chamber S1 is not disposed coaxially with the housing 101, the sliding directions of the first and second pistons 121 and 122 become directions different from the axial direction of the housing 101.

[0110] Further, for example, the cross-sectional shape of the first liquid chamber S1 orthogonal to the sliding directions of the first and second pistons 121 and 122 can also not be a circular shape. The cross-sectional shape can also be, for example, an elliptical shape or a polygonal shape, or the like. In this case, the circumferential direction of each of the first and second pistons 121 and 122 is also a direction along the outer periphery of each of the first and second pistons 121 and 122, and becomes a direction around the central axis of each of the first and second pistons 121 and 122.

[0111] Further, for example, the cross-sectional shape of the protruding member 161 orthogonal to the axial direction can also not be a circular shape. The cross-sectional shape can also be, for example, an elliptical shape or a polygonal shape, or the like. In this case, the circumferential direction of the protruding member 161 is also a direction along the outer periphery of the protruding member 161, and becomes a direction around the central axis of the protruding member 161.

[0112] Further, for example, for the example of Figure 2 Even if the shape of the second valve body 152 is not a spherical shape, as long as it is a shape that functions as an on-off valve.

[0113] Further, for example, for the example of Figure 2 The first opening PO1 can also be provided to the first cover 111 instead of the peripheral wall portion of the housing 101.

[0114] Reference Signs 1 brake system 15 hydraulic control unit 17 wheel 36 pump 100 attenuator 101 housing 111 first cover 112 second cover 113 third cover 113c communication hole 114 fourth cover 121 first piston 121e hole portion 122 second piston 122c first through-hole 141 first urging member 142 second urging member 143 3rd urging member 144 4th urging member 151 1st valve body 152 2nd valve body 161 protruding member 161c protrusion 161d recess 161e 2nd through-hole P1 inlet port P2 outlet port PO1 1st opening PO2 2nd opening S1 1st liquid chamber S2 2nd liquid chamber 300 sliding member 300a internal passage 300b 5th urging member 301 damping chamber 302 connecting hole 303 blocking member

Claims

1. An attenuation device (100) provided in a hydraulic control unit (15) that controls a braking force generated at a wheel (17), having an inlet port (Pl) connected to a discharge side of a pump (36) and an outlet port (P2) communicating with the aforementioned inlet port (Pl) to attenuate pressure pulsation, characterized by comprising: a first liquid chamber (Sl) communicating with the aforementioned inlet port (Pl) via a first opening (POl); a second liquid chamber (S2) communicating with the aforementioned first liquid chamber (Sl) via a communication hole (113c) and communicating with the aforementioned outlet port (P2) via a second opening (PO2); a first piston (121) slidably provided in the aforementioned first liquid chamber (Sl); a first urging member (141) urging the aforementioned first piston (121) toward the aforementioned first opening (POl) side; a hole portion (121e) recessed in the aforementioned first piston (121) from the aforementioned second opening (PO2) side toward the aforementioned first opening (POl) side; a second piston (122) slidably provided in the aforementioned hole portion (121e); a second urging member (142) urging the aforementioned second piston (122) toward the aforementioned first opening (POl) side; a first through hole (122c) provided in the aforementioned second piston (122) and passing through from the aforementioned first opening (POl) side to the aforementioned second opening (PO2) side; a first valve body (151) capable of opening and closing the aforementioned first opening (POl) side of the aforementioned first through hole (122c); a third urging member (143) urging the aforementioned first valve body (151) toward the aforementioned second opening (PO2) side; a protrusion member (161) having a protrusion portion (161c) capable of being inserted into the aforementioned first through hole (122c) and capable of abutting against the aforementioned first valve body (151) and provided in the aforementioned first piston (121) on the aforementioned second opening (PO2) side with respect to the aforementioned second piston (122) and moving integrally with the aforementioned first piston (121); a second valve body (152) provided in the aforementioned second liquid chamber (S2) and capable of opening and closing the aforementioned second opening (PO2) side of the aforementioned communication hole (113c); and a fourth urging member (144) urging the aforementioned second valve body (152) toward the aforementioned first opening (POl) side; and further comprising: a sliding member (300) disposed in a recessed portion (161d) of the aforementioned protrusion member (161), sliding in the aforementioned hole portion (161d) according to pressure fluid from the aforementioned inlet port (Pl) side, and having an internal passage (300a); and a fifth urging member (300b) urging the aforementioned sliding member (300) toward the aforementioned first opening (POl) side.

2. The attenuation device according to claim 1, characterized in that the aforementioned hole portion (161d) is formed at an end portion on the opposite side of the aforementioned protrusion portion (161c).

3. The attenuation device according to claim 1 or 2, characterized in that ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ The aforementioned slide member (300) is extended and contracted by the aforementioned 5th force applying member (300b), and the volume of the damping chamber (301) formed on the input port (P1) side of the aforementioned slide member (300) is expanded and contracted.

4. The damping device according to any one of claims 1 to 3, characterized in that On the aforementioned 2nd fluid chamber (S2) side end portion of the aforementioned protrusion member (161), an occlusion member (303) is integrally installed on the aforementioned protrusion member (161); In the occlusion member (303), a connection hole (302) is formed which communicates between the aforementioned damping chamber (301) and the aforementioned 2nd fluid chamber (S2).

5. The damping device according to any one of claims 1 to 4, characterized in that One end of the aforementioned 5th force applying member (300b) is engaged with the slide member (300), and the other end is engaged with the aforementioned occlusion member (303), and the aforementioned slide member (300) is urged to the inaction state.

6. A hydraulic control unit characterized in that The damping device (100) according to any one of claims 1 to 5 is provided.

7. A brake system characterized in that The hydraulic control unit (15) according to claim 6 is provided.

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