Damping device, hydraulic control unit, and brake system

Abstract

The present invention dampens pulsations in the pressure of a hydraulic control unit. This damping device comprises a first liquid chamber communicating with a master cylinder and the discharge side of a pump, a second liquid chamber communicating with the first liquid chamber and the master cylinder, a first opening / closing member for opening / closing the communication between the first liquid chamber and the second liquid chamber, a first piston provided in the second liquid chamber, a second piston formed in the first piston and provided in an internal space opened to the first-liquid-chamber side, and a second opening / closing member for opening / closing a space on the side of the second piston away from the first liquid chamber within the internal space and a space on the side of the first piston away from the first liquid chamber within the second liquid chamber. When the pump is driven while a brake operation is performed, the first opening / closing member is in an open state, and the second opening / closing member is opened / closed according to sliding of the second piston with respect to the first piston. When the pump is driven while the brake operation is not performed, the first opening / closing member is in a closed state, and the second opening / closing member is in a closed state.

Description

[0001] upon receipt of translation, please add the JAP modified Title (J LA)

Document Name

[0002]

Title of the Invention

[0003]

Technical Field

[0004]

[0001]

[0005] The present invention relates to a damping device, a hydraulic pressure control unit, and a brake system.

[0006]

Background Art

[0007]

[0002]

[0008] In a conventional vehicle, a hydraulic pressure control unit is provided to control the braking force generated on wheels. For example, as disclosed in Patent Document 1, a plurality of valves and a pump are provided in a flow passage within the hydraulic pressure control unit. In such a hydraulic pressure control unit, for example, in antilock brake control or the like, control is performed to drive the pump by setting the open / close states of each valve to a specific state.

[0009]

Prior Art Literature

[0010]

Patent Literature

[0011]

[0003]

[0012]

Patent Document 1

[0013]

Summary of the Invention

[0014]

Problem to be Solved by the Invention

[0015]

[0004]

[0016] Incidentally, in hydraulic control units, a plunger pump that primarily moves in a reciprocating motion is used as the pump. Therefore, the pumping of brake fluid is performed intermittently. Consequently, when the pump is driven, pressure pulsation occurs in the fluid passages within the hydraulic control unit, causing fluctuations in the brake fluid pressure. The sound produced by such pressure pulsation can be perceived as noise by the vehicle's occupants and can impair comfort. In particular, when anti-lock brake control is in operation, the sound produced by pressure pulsation is likely to impair comfort. Therefore, from the perspective of improving comfort, it is desirable to appropriately attenuate the pressure pulsation in the hydraulic control unit.

[0017] [ 0 0 0 5 ]

[0018] Therefore, in view of these problems, the present invention aims to provide a damping device, a hydraulic control unit, and a brake system that can dampen the pressure pulsation of a hydraulic control unit.

[0019] [Means for solving the problem]

[0020] [ 0 0 0 6 ]

[0021] To solve the above problem, the damping device is provided in a hydraulic control unit that controls the braking force generated in the wheel, and is positioned in the brake fluid flow path between the discharge side of the pump and the master cylinder, and is a damping device that dampens pressure pulsations, and has a first number that communicates with the discharge side of the pump and the master cylinder, respectively! The pump comprises a liquid chamber, a second liquid chamber communicating with the first liquid chamber and the master cylinder, a first opening / closing member that opens and closes the space between the first and second liquid chambers, a first piston slidably mounted in the second liquid chamber, a first internal space formed inside the first piston and opening towards the first liquid chamber, a second piston provided in the first internal space and slidably mounted relative to the first piston, and a second opening / closing member that opens and closes the space in the first internal space opposite the first liquid chamber relative to the second piston and the space in the second liquid chamber opposite the first piston. When the pump is driven while the brakes are being applied, the first piston moves towards the first liquid chamber, causing the first opening / closing member to open, and the second opening / closing member opens relative to the first piston. As the piston slides, the opening and closing mechanism opens and closes. When the pump is running without brake operation, the first piston moves to the opposite side of the first liquid chamber, causing the first opening / closing member to close and the second opening / closing member to close.

[0022] [ 0 0 0 7 ]

[0023] To solve the above problems, the hydraulic control unit is equipped with the damping device described above.

[0024] [0 0 0 8] To solve the above problem, the brake system is equipped with the above-mentioned hydraulic control unit. [Effects of the invention]

[0025] [ 0 0 0 9 ]

[0026] According to the present invention, it is possible to attenuate the pressure pulsation of the hydraulic control unit.

[0027] [Brief explanation of the drawing]

[0028] [ 0 0 1 0 ]

[0029] [Figure 1] This is a schematic diagram showing the general configuration of a brake system according to the first embodiment of the present invention.

[0030] [Figure 2] This is a cross-sectional view showing the schematic configuration of the damping device according to the first embodiment of the present invention. [Figure 3] This is a diagram showing the state of the damping device according to the first embodiment of the present invention during the execution of anti-lock brake control.

[0031] [Figure 4] This figure shows the state of the damping device according to the first embodiment of the present invention during the execution of emergency automatic braking.

[0032] [Figure 5] This is a cross-sectional view showing the schematic configuration of the damping device according to the second embodiment of the present invention. [Figure 6] This is a diagram showing the state of the damping device according to the second embodiment of the present invention during the execution of anti-lock brake control.

[0033] [Figure 7] This figure shows the state of the damping device according to the second embodiment of the present invention during the execution of emergency automatic braking.

[0034] [Modes for Carrying Out the Invention]

[0035] [ 0 0 1 1 ]

[0036] Preferred embodiments of the present invention will be described in detail below with reference to the attached drawings. The dimensions, materials, and other specific numerical values ​​shown in these embodiments are merely illustrative to facilitate understanding of the invention and, unless otherwise specified, do not limit the present invention. In this specification and in the drawings, elements having substantially the same function and configuration are denoted by the same reference numerals to avoid redundant explanation, and elements not directly related to the present invention are omitted from the illustration.

[0037] [ 0 0 1 2 ]

[0038] In this embodiment, a vehicle having four wheels 17 is described as an example, but the vehicle to which the present invention applies is not limited to a vehicle having four wheels 17. For example, it may be a vehicle having one, two, or three wheels 17, or a vehicle having five or more wheels 17.

[0039] [ 0 0 1 3 ]

[0040] V First Embodiment >

[0041] A first embodiment of the present invention will be described with reference to FIGS. 1 to 4.

[0042] [ 0 0 1 4 ]

[0043] (Configuration of Brake System)

[0044] With reference to FIG. 1, the configuration of a brake system 1 according to a first embodiment of the present invention will be described.

[0045] [ 0 0 1 5 ]

[0046] FIG. 1 is a schematic diagram showing a schematic configuration of the brake system 1. The brake system 1 is a system mounted on a vehicle for controlling braking force generated in the vehicle. As shown in FIG. 1, the brake system 1 includes a brake pedal 11, a booster 12, a master cylinder 13, a reservoir 14, a hydraulic pressure control unit 15, a brake device 16, and wheels 17.

[0047] [ 0 0 1 6 ]

[0048] The brake system 1 is mounted on a vehicle having four wheels 17, and each wheel 17 is braked by the brake device 16 provided on each wheel 17. The braking force generated on each wheel 17 is controlled by the hydraulic pressure control unit 15. In FIG. 1, for ease of understanding, of the total four wheels 17, only portions related to two wheels 17 (e.g., the left front wheel and the right rear wheel) are shown, and illustration of portions related to the other two wheels 17 (e.g., the right front wheel and the left rear wheel) is omitted.

[0049] [ 0 0 1 7 ]

[0050] Furthermore, the number of wheels 17 whose braking force is controlled by the hydraulic control unit 15 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 1 can be installed on a vehicle having two wheels 17.

[0051] [ 0 0 1 8 ]

[0052] Brake pedal 11 is used by the driver to operate the brakes. During braking, the brake pedal 11 is pressed down by the driver. The power assist device 12 is connected to the brake pedal 11 and amplifies the force applied to the brake pedal 11. The master cylinder 13 is connected to the power assist device 12 and contains a piston that reciprocates in conjunction with the brake pedal 11, generating hydraulic pressure corresponding to the amount of brake operation. The reservoir 14 is attached to the master cylinder L3 and stores brake fluid.

[0053] [ 0 0 1 9 ]

[0054] The hydraulic control unit 15 comprises a base 15a in which a brake fluid flow path is formed. The master cylinder 13 and each brake device 16 are connected to the base 15a of the hydraulic control unit 15. The brake fluid flow path of 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 on the wheel 1y.

[0055] [ 0 0 2 0 ]

[0056] The base 15a of the hydraulic control unit 15 has a main passage 21, a secondary passage 22, and a supply passage 23 formed as brake fluid passages. The main passage 21 circulates the brake fluid from the master cylinder 13 to the wheel cylinder of the brake device 16. The secondary passage 22 releases the brake fluid from the wheel cylinder of the brake device 16. The supply passage 23 supplies the brake fluid from the master cylinder 13 to the secondary passage 22. Note that a portion of the above passages includes the internal passages of the damping device 1〇〇, which will be described later.

[0057] [ 0 0 2 1 ]

[0058] Furthermore, the base 5a of the hydraulic control unit 15 is equipped with a fill 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.

[0059] [ 0 0 2 2 ]

[0060] The hydraulic control unit 15 only needs to have a pump 36, and components may be added or omitted compared to the example shown in Figure 1.

[0061] [ 0 0 2 3 ]

[0062] The main flow path 21 connects the master cylinder 13 and the wheel cylinder of the brake 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 21b branch off from the first main flow path 21a and are connected to each brake device 16. The first main flow path 21a is provided with a first valve 33. The second main flow paths 21b are provided with a suction valve 31.

[0063] [ 0 0 2 4 ]

[0064] The sub-flow channel 22 connects the brake device 16 side from the suction valve 31 in the main flow channel 21, the master cylinder 13 side from the suction valve 31 in the main flow channel 21, and the brake device 16 side from the first valve 33. The sub-flow channel 22 includes two first sub-flow channels 22a and a second sub-flow channel 22b. Each first sub-flow channel 22a is connected to the brake device 16 side from the suction valve 31 in the main flow channel 21. The second sub-flow channel 22b connects the confluence of the two first sub-flow channels 22a to the master cylinder 13 side of the main flow channel 21 via the suction valve 31, and to the brake device 16 side of the first valve 33. The first sub-flow channel 22a is provided with a release valve 32. The second sub-flow channel 22b is provided with an accumulator 35 and a pump 36, in order from the first sub-flow channel 22a side.

[0065] [0 0 2 5] Pump 36 is driven by motor 37 and draws brake fluid from the first sub-flow channel 22a side and discharges it to the main flow channel 21 side. Pump 36 is a reciprocating plunger pump. Specifically, the plunger of pump 36 reciprocates by being intermittently pressed by an eccentric cam provided on the output shaft of motor 37. This causes pump 36 to pump the brake fluid.

[0066] [ 0 0 2 6 ]

[0067] The supply passage 23 connects the master cylinder 13 side of the first valve 33 in the main passage 21 to the suction side of the pump 36 in the sub-passage 22. A second valve 34 is provided in the supply passage 23.

[0068] [ 0 0 2 7 ]

[0069] The suction valve 31 is, for example, a solenoid valve that is open when de-energized and closed when energized. The release valve 32 is, for example, a solenoid valve that is closed when de-energized and opened when energized. The first valve 33 is, for example, a solenoid valve that is open when de-energized and closed when energized. The second valve 34 is, for example, a solenoid valve that is closed when de-energized and opened when energized. The braking force generated on each wheel 1y is controlled by controlling the operation of these valves and the motor 37.

[0070] [ 0 0 2 8 ]

[0071] For example, under normal conditions when anti-lock brake control or emergency automatic braking, as described later, is not being performed, the loading valve 31 is opened, the release valve 32 is closed, the first L valve 33 is opened, and the second valve 34 is closed. As a result, brake fluid flows from the master cylinder 13 to the wheel cylinder of the brake device 16 only through the main passage 21, without going through the sub-passage 22 and the supply passage 23. In this state, when the brake pedal 11 is pressed, the piston of the master cylinder 13 is pushed in, increasing the hydraulic pressure of the brake fluid in the wheel cylinder, and applying braking force to the wheel 17.

[0072] [ 0 0 2 9 ]

[0073] Anti-lock brake control is a control system designed to prevent wheel 17 from locking. Anti-lock brake control is performed when braking is being applied. Anti-lock brake control prevents wheel 17 from locking by reducing the braking force generated on wheel 17 in response to the braking operation.

[0074] [ 0 0 3 0 ]

[0075] For example, when anti-lock brake control is performed, first the loading valve 31 is closed, the release valve 32 is opened, the first valve 33 is opened, and the second valve 34 is closed. As a result, the flow of brake fluid between the main passage 21 and the wheel cylinder of the brake device 16 is stopped, and brake fluid becomes able to flow from the wheel cylinder to the sub-passage 22. Therefore, 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. In this state, the pump 36 is driven, and the brake fluid that has flowed into the accumulator 35 is returned to the main passage 21 via the sub-passage 22.

[0076] [ 0 0 3 1 ]

[0077] Then, as described above, both the loading valve 31 and the release valve 32 are closed, stopping the flow of brake fluid between the main flow path 21 and the 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. Subsequently, when the loading valve 31 is opened and the release valve 32 is closed, the flow of brake fluid between the main flow path 21 and the wheel cylinder resumes, increasing the hydraulic pressure of the brake fluid in the wheel cylinder and increasing the braking force applied to the wheel 17.

[0078] [ 0 0 3 2 ]

[0079] In the following, we will explain an example of when pump 3 6 is driven while braking is being performed, specifically when anti-lock brake control is being implemented. However, when pump 3 6 is driven while braking is being performed, the anti-lock brake control is not implemented.

[0080]

[0081] [ 0 0 3 3 ]

[0082] The emergency automatic braking system is activated when the likelihood of a vehicle colliding with an obstacle, such as another vehicle, exceeds a certain threshold, and is designed to automatically stop the vehicle. The emergency automatic braking system is activated when no brakes are being applied. The system avoids collisions by automatically applying braking force to the wheels 17.

[0083] [ 0 0 3 4 ]

[0084] For example, when the emergency automatic brake is activated, first the loading 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, brake fluid flows from the master cylinder 13 to the wheel cylinder of the brake device 6 via the supply passage 23 and the sub-passage 22. In this state, the pump 36 is driven, increasing the hydraulic pressure of the brake fluid in the wheel cylinder and generating a braking force to stop the wheel 17.

[0085] [ 0 0 3 5 ]

[0086] In the following, we will explain an example of when pump 3 6 is operating while no brake operation is performed, using the case where emergency automatic braking is activated. However, when pump 3 6 is operating while no brake operation is performed, other types of control may also be activated.

[0087] [ 0 0 3 6 ]

[0088] As described above, the hydraulic control unit 15 controls the operation of the pump 36. When the pump 36 is driven, pressure pulsation occurs in the fluid passages within the hydraulic control unit 15, causing fluctuations in the brake fluid pressure. The noise generated by such pressure pulsation can be perceived as noise by the vehicle's occupants and can impair comfort. In particular, when anti-lock brake control is in operation, the noise generated by pressure pulsation is likely to impair comfort. Therefore, the hydraulic control unit 15 is equipped with a damping device 100 to reduce pressure pulsation.

[0089] [ 0 0 3 7 ]

[0090] The damping device 100 is positioned in the brake fluid flow path between the discharge side of the pump 36 and the master cylinder 13. In the example shown in Figure 1, the damping device 100 spans the portion of the first main flow path 21a between the fill valve 31 and the first valve 33, and the portion of the second subflow path 22b downstream of the pump 36. The damping device 100 has ports P1, P2, P3, and P4.

[0091] [ 0 0 3 8 ]

[0092] Within the damping device 100, ports P2 and P4 are in communication with each other. Port P2 is connected to the portion of the first main flow path 21a that is on the side of the containment valve 31 relative to the damping device 100. Port P4 is connected to the portion of the first main flow path 21a that is on the side of the first valve 33 relative to the damping device 100. In other words, the first main flow path 21a passes through ports P2 and P4. To put it another way, the flow path connecting ports P2 and P4 within the damping device 100 is included in the first main flow path 21a.

[0093] [ 0 0 3 9 ]

[0094] Inside damping device 1 XX, ports P1 and P3 are in communication with each other. Port P1 is connected to the portion of the second sub-flow channel 2 2 b that is on the pump 3 6 side relative to damping device XX. Port P3 is connected to the portion of the second sub-flow channel 2 2 b that is on the first main flow channel 2 1 a side relative to damping device 1 XX. In other words, the second sub-flow channel 2 2 b passes through ports P1 and P3. To put it another way, the flow channel connecting ports P1 and P3 inside damping device 1 XX is included in the second sub-flow channel 2 2 b.

[0095] [ 0 0 4 0 ]

[0096] (Configuration of the damping device)

[0097] Referring to Figure 2, the details of the configuration of the damping device 100 according to the embodiment of the present invention will be described.

[0098] [0 0 4 1] Figure 2 is a cross-sectional view showing the schematic configuration of the damping device 100. Specifically, Figure 2 shows the damping device 100 under normal circumstances when brake operation is being performed, and when anti-lock brake control or emergency automatic braking is not being performed. Note that the damping device 100 shown in Figure 2 is merely one example of a damping device according to the present invention, and various modifications to the example in Figure 2, as described later, are also included in the damping device according to the present invention.

[0099] [ 0 0 4 2 ]

[0100] As shown in Figure 2, the damping device 100 comprises a housing 101, a cover 111, a cover 112, a valve seat 113, an opening / closing member 122, an opening / closing member 123, a piston 131, a piston 132, a piston 133, a biasing member 42, a biasing member 142, and an elastic member 151. Note that opening / closing members 121, 122, 123, pistons 131, 132, and 133 correspond to examples of the first opening / closing member, third opening / closing member, second opening / closing member, first piston, second piston, and third piston according to the present invention.

[0101] [ 0 0 4 3 ]

[0102] The housing I101 is formed in a cylindrical shape with a hollow space inside. In Figure 2, the damping device 100 is shown such that the axial direction of the housing 101 is the left-right direction. Hereafter, the left-right direction in the drawings will also be simply referred to as the left-right direction. Note that the left-right direction in Figures 3 and 4, which will be described later, coincides with the left-right direction in Figure 2.

[0103] [ 0 0 4 4 ]

[0104] The hollow space inside housing 1 is open on the left side of housing 1 and closed on the right side. The inner circumferential surface 1a of housing 1 is formed in a substantially cylindrical shape.

[0105] [ 0 0 4 5 ]

[0106] Of the hollow space inside housing Z e 〇 1, the space where the cover 1 1 1 described later is placed corresponds to the first liquid chamber s !. Of the hollow space inside housing 1 〇 1, the space to the right of the cover 1 1 1 described later corresponds to the second liquid chamber S 2.

[0107] [ 0 0 4 6 ]

[0108] The aforementioned ports P1, P2, P3, and P4 are formed on the outer circumferential surface of the housing 101.

[0109] [ 0 0 4 7 ]

[0110] Port p1 communicates with the first liquid chamber S1 through a through hole 10b formed in the housing 101. The through hole 10b extends radially in the housing 101 and opens to the inner circumferential surface 10a.

[0111] [ 0 0 4 8 ]

[0112] Port P2 communicates with the second liquid chamber S2 through a through-hole ☐c formed in the housing 1☐c. The through-hole ☐c extends radially in the housing 1☐c and opens to the inner circumferential surface 1☐a.

[0113] [ 0 0 4 9 ]

[0114] Port P3 communicates with the first liquid chamber S1 through a hole 101d formed in the housing 101. For example, hole 101 is located outside the inner circumferential surface 101a in the radial direction of the housing 101 and has a cylindrical shape that extends radially along the housing 101. On the outer circumferential surface side of hole 101d, a groove 101e is provided, which is formed in an annular shape coaxial with hole 101d and whose inner diameter expands. An annular cover 112 is provided in groove 101e. The outer circumferential surface of cover 112 is fitted to the inner circumferential surface of groove 101e. The through hole formed in the center of cover 112 corresponds to port P3. On the inner circumferential surface side of hole 101d, a through hole 101f is provided. Through hole 101f connects hole 101d to the first liquid chamber S.

[0115] [ 0 0 5 0 ]

[0116] Port P4 communicates with the second liquid chamber S2 through a through-hole g formed in the housing 1. The through-hole g extends radially in the housing 1 and opens to the inner circumferential surface 1.

[0117] The first liquid chamber S1 is connected to the discharge side of the pump 36 via port P1 and to the master cylinder 13 via port P3. The second liquid chamber S2 is connected to the first liquid chamber S1 and to the master cylinder 13 via port P4.

[0118] [ 0 0 5 2 ]

[0119] Cover 111 is provided in the first liquid chamber S1. Cover 111 has a substantially cylindrical shape that extends axially from housing 1. Cover 111 is, for example, positioned coaxially with housing 1. The outer circumferential surface of cover 111 is fitted into the inner circumferential surface 101a. Cover 111 is fixed to housing 101. Cover 111 has a hole 111a and a groove 111

[0120] A through hole 111d and a groove 111 are provided.

[0121]

[0122] Hole 111a is positioned coaxially with cover 111, opening on the right side of cover 111 and closing on the left side. Hole 111a has a substantially cylindrical shape and extends axially along cover 111. Groove 111b is formed in an annular shape coaxial with hole 111a to the right of hole 111a, and is a portion where the inner diameter expands. Through hole 111c connects hole 111a and through hole 111b. Through hole 111c extends radially along housing 111, for example. Through hole 111d connects hole 111a and through hole 101f. The through hole 111d extends radially to the housing 1〇1, for example. The groove 111e is formed in an annular shape on the right side surface of the cover 111, recessed to the left. The groove 111e is positioned coaxially with the cover 111, for example. The groove 111e is located radially outward of the cover 111 relative to the groove 111b.

[0123] [ 0 0 5 4 ]

[0124] The opening / closing member 121 is provided in the hole 1Ila of the cover 111. The opening / closing member 121 includes a valve body 121a and a biasing member 121b. The valve body 121a is, for example, spherical. The biasing member 121b is, for example, a spring. The biasing member 121b is positioned between the bottom surface of the hole Illa (i.e., the right-facing surface) and the valve body 21a. The biasing member 21b is positioned so that its expansion and contraction direction is left-right, and is in a contracted state relative to its natural length. Therefore, the valve body 121a is biased to the right by the biasing member 121b.

[0125] [ 0 0 5 5 ]

[0126] The valve seat 113 is provided in the groove 111b of the cover 111. The valve seat 113 is formed in an annular shape coaxial with the housing 1. The valve seat 113 is provided with a through hole 113a that penetrates the valve seat 113 in the left-right direction. The outer circumferential surface of the valve seat 113 is fitted into the inner circumferential surface of the groove 111b. The valve seat 113 is fixed to the cover 111.

[0127] [ 0 0 5 6 ]

[0128] The valve body 121a of the opening / closing member 121 is positioned to the left of the through hole 113a of the valve seat 113, and the diameter of the valve body 121a is larger than the diameter of the through hole 113a. The valve body 121a can abut against the edge of the through hole 113a.

[0129] 0 0 5 7 ]

[0130] In the example shown in Figure 2, the valve body 121a is separated from the edge of the through hole 13a. In this case, the through hole 113a is opened by the valve body 121a, and the space between the first fluid chamber S1 and the second fluid chamber S2 is opened (that is, brake fluid can flow between the first fluid chamber S1 and the second fluid chamber S2).

[0131] [ 0 0 5 8 ]

[0132] On the other hand, when the valve body 121a comes into contact with the edge of the through hole 13a, the through hole 113a is closed by the valve body 121a, and the space between the first fluid chamber S1 and the second fluid chamber S2 is closed (that is, brake fluid cannot flow between the first fluid chamber S1 and the second fluid chamber S2). In this way, the valve body 121a opens and closes the through hole 113a of the valve seat 113, thereby opening and closing the space between the first fluid chamber S1 and the second fluid chamber S2.

[0133] [ 0 0 5 9 ]

[0134] The opening / closing member 122 is provided in the hole 10d of the housing 10!. The opening / closing member 122 includes a valve body 22a and a biasing member 122b. The valve body 122a has, for example, a spherical shape. The biasing member 122b is, for example, a spring. The biasing member 22b is positioned between the cover 112 and the valve body 22a. The biasing member 22b is positioned so that its expansion and contraction direction is radial to the housing 101, and is in a contracted state relative to its natural length. Therefore, the valve body 122a is biased toward the through hole 101f by the biasing member 122b.

[0135] [ 0 0 6 0 ]

[0136] The valve body 122a of the opening / closing member 122 is positioned radially outward of the housing 101 relative to the through hole 101f. The diameter of the valve body 122a is greater than the diameter of the through hole 01f. The valve body 122a can abut against the edge of the through hole 101f.

[0137] [ 0 0 6 1 ]

[0138] In the example shown in Figure 2, the valve body 122a is in contact with the edge of the through hole 101f. In this case, the through hole 101f is closed by the valve body 22a, and the space between the first fluid chamber S1 and the port P3 is closed (i.e., brake fluid cannot flow between the first fluid chamber S1 and the master cylinder 13).

[0139] [ 0 0 6 2 ]

[0140] On the other hand, when the valve body 122a is separated from the edge of the through hole 101f, the through hole 101f is opened by the valve body 122a, and the space between the first fluid chamber S1 and the port P3 is opened (that is, brake fluid can flow between the first fluid chamber S1 and the master cylinder 13). In this way, the opening and closing member 122 opens and closes the space between the first fluid chamber S1 and the master cylinder 13 by opening and closing the through hole 101f with the valve body 122a.

[0141] [ 0 0 6 3 ]

[0142] The piston 131 is provided in the second liquid chamber S2. The piston 131 has a substantially cylindrical shape that extends axially from the housing 101. The piston 131 is provided in the housing 101, for example. The piston 131 is provided in the second liquid chamber S2 so as to be slidable in the axial direction. The piston 131 consists of a body 131a, a cover 131b, and a cover 131c, which form the general shape of the piston 131. The body 131a has a substantially cylindrical shape. The body 131a is provided in the housing 101, for example. The outer surface of the main body 131a is slidable relative to the inner surface 01a, and is provided with a seal 131al, a hole 131a2, a groove 31a3, a hole 1a5, and a through hole 131a6.

[0143] For example, a ring. Seal 131a1 is formed on the body 131a and fitted onto the outer surface of the body 131a. Seal 13

[0144]

[0145] It is pressed against 1a. This seals the gap between the outer surface of the main body 131a and the inner surface 1Ola into a liquid-tight seal. In the example in Figure 2, there are two seals 131a1. However, there may be one seal 131al or three or more seals.

[0146] [ 0 0 6 6 ]

[0147] Hole 131a2 is positioned coaxially with the main body 131a, opening to the left side of the main body 131a and closing to the right side. Hole 131a2 has a substantially cylindrical shape that extends axially along the main body 131a. As will be described later, hole 131a2 opens to the first liquid chamber S1 side through the through hole 131b1 of the cover 131b. In other words, hole 131a2 corresponds to the first internal space S3 formed inside the piston 131 and opening to the first liquid chamber S1 side.

[0148] [ 0 0 6 7 ]

[0149] Groove 131a3 is formed to the left of hole 131a2, coaxially with hole 131a2, and is an annular shape in which the inner diameter expands. Cover 131b is fitted into this groove 131a3.

[0150]

[0151] It is fixed in place. The cover 131b is formed in a substantially disc shape coaxial with the housing 101. The outer surface of the cover 131b is fitted into the inner surface of the groove 131a3. The cover 131b is provided with a through hole 131b1 and a projection 131b2.

[0152] bl penetrates the cover 131b in the left-right direction. Therefore, it connects the first internal space S3 of the through-hole 131b to the first liquid chamber S!. For example, multiple 1s are provided at intervals around the circumferential direction of the cover 131b. However, the number of 1s may be just one.

[0153] Projection 2 protrudes to the left from the left end face of cover 131b. Projection 131b2 is coaxial with . In the example in Figure 2, the tip of projection 131b2 (i.e., located to the left of hole 113a) is pushed by the valve body 121a to the left of projection 1, thereby opening the through hole 113a. Hole 131a4 is coaxial with body 131a and closes to the right of body 131a. Hole 131a4 is a roughly circular hole extending axially from body 131a.

[0154]

[0155] This is a portion formed to the right of hole 31a4, coaxially with hole 131a4, in an annular shape, and whose inner diameter is enlarged. Cover 131c is fitted into this groove 131a5.

[0156] [ 0 0 7 3 ]

[0157] The cover 131c is fixed to the groove 131a5 of the main body 131a. The cover 131c is formed in a substantially annular shape coaxial with the housing 1〇1. The outer circumferential surface of the cover 131c is fitted to the inner circumferential surface of the groove 131a5.

[0158] [ 0 0 7 4 ]

[0159] The through hole 131a6 is located on the left side of hole 131a4. The through hole 131a6 connects hole 131a4 to the first internal space S3 of piston 131.

[0160] [ 0 0 7 5 ]

[0161] The biasing member 141 is, for example, a spring. The biasing member 141 is positioned between the bottom surface of the groove 111e of the cover 111 (i.e., the side facing to the right) and the body 131a of the piston 131. The biasing member 141 is positioned so that its extension and contraction direction is left-right, and is in a contracted state relative to its natural length. Therefore, the piston 131 is biased to the right by the biasing member 141.

[0162] [ 0 0 7 6 ]

[0163] The piston 132 is located in the first internal space S3 of the piston 131. The piston 132 has a substantially cylindrical shape that extends axially from the housing 101. The piston 132 is, for example, positioned coaxially with the housing 101. The piston 132 is slidably mounted axially within the first internal space S3. That is, the piston 132 is slidably mounted relative to the piston 131. The piston 132 includes a body 132a and a cover 132b.

[0077]

[0164] The main body 132a forms the general shape of the piston 132. The main body 132a has a substantially cylindrical shape that extends axially from the housing 1〇1. The main body 132a is arranged coaxially with the housing 101, for example. The outer circumferential surface of the main body 132a is slidable against the inner circumferential surface of the hole 131a2 of the piston 131. The main body 132a is provided with a seal 132al and a hole 132a2.

[0165] [ 0 0 7 8 ]

[0166] The seal 132a1 is, for example, an O-ring. The seal 132a1 is formed in an annular shape extending circumferentially from the body 132a and is fitted to the outer circumferential surface of the body 132a. The seal 132a1 is pressed against the inner circumferential surface of the hole 131a2 of the piston 131. This ensures that the gap between the outer circumferential surface of the piston 132 and the inner circumferential surface is liquid-tight.

[0167]

[0168] The seals are sealed. In the example in Figure 2, there are two seals 132a1. However, the number of seals 132a1 may be one or three or more.

[0169] [ 0 0 7 9 ]

[0170] Hole 132a2 is positioned coaxially with the main body 132a, opening to the left side of the main body 132a and closing to the right side. Hole 132a2 has a substantially cylindrical shape that extends in the axial direction of the main body l32a. As will be described later, hole 132a2 opens to the first liquid chamber S1 side through a through hole in the cover 132b. In other words, hole 132a2 is formed inside the piston 132 and corresponds to the second internal space S4 that opens to the first liquid chamber S1 side.

[0171] [ 0 0 8 0 ]

[0172] Cover 132b is fixed to the left side of the inner circumferential surface of hole 132a2 in the main body 132a. Cover 132b is formed in a substantially annular shape coaxial with housing 101. The outer circumferential surface of cover 132b is fitted to the inner circumferential surface of hole 132a2. The second internal space S4 of piston 132 communicates with the first liquid chamber S1 through a through hole provided in the center of cover 132b.

[0173] [ 0 0 8 1 ]

[0174] The biasing member 142 is, for example, a spring. The biasing member 142 is provided in the first internal space S3 of the piston 131. The biasing member 142 is positioned between the bottom surface of the hole 131a2 (i.e., the side facing left) and the piston 132. The biasing member 142 is positioned in a posture where its expansion and contraction direction is left-right, and is in a contracted state relative to its natural length. Therefore, the piston 132 is biased to the left by the biasing member 142.

[0175] [ 0 0 8 2 ]

[0176] Piston 133 is provided in the second internal space S4 of piston 132. Piston 133 has a substantially cylindrical shape that extends axially from the housing 101. Piston 133 is, for example, positioned coaxially with the housing 101. Piston 133 is provided so as to be axially slidable in the second internal space S4. The outer circumferential surface of piston 133 is slidable against the inner circumferential surface of the hole 132a2 of piston 132. In other words, piston 133 is provided so as to be slidable relative to piston 132. A seal 133a is provided on piston 133.

[0177] [ 0 0 8 3 ]

[0178] The seal 133a is, for example, an O-ring. The seal 133a is formed in an annular shape extending circumferentially around the piston 133 and is fitted onto the outer surface of the piston 133. The seal 133a is pressed against the inner surface of the hole 132a2 of the piston 132. This seals the gap between the outer surface of the piston 133 and the inner surface of the hole 132a2 of the piston 132 in a liquid-tight seal. In the example in Figure 2, there is one seal 133a. However, there may be two or more seals 133a.

[0179] [ 0 0 8 4 ]

[0180] The elastic member 151 is provided in the space to the right of the piston 133 within the second internal space S4 of the piston 132. The elastic member 151 is attached to at least one of the pistons 132 and l33, sandwiched between the bottom surface of the hole 132a2 of the piston 132 (i.e., the side facing left) and the piston l33. The elastic member 151 may be fixed to both the piston 132 and the piston 133, or to only one of the pistons 132 and l33. The elastic member 151 is formed of a material with a high elastic limit, such as rubber.

[0181] [ 0 0 8 5 ]

[0182] The elastic member 151 has a substantially cylindrical shape. The elastic member L51 is positioned coaxially with, for example, the housing 101. The left end face of the elastic member 151 is in contact with the right end face of the piston 133, and the right end face of the elastic member 15I is in contact with the bottom surface (i.e., the left-facing side) of the hole 132a2 of the piston l32.

[0183] [ 0 0 8 6 ]

[0184] The elastic member 151 includes multiple regions R1, R2, and R3 with different hardnesses. Specifically, the hardness of each region decreases in the order of R1, R2, and R3. That is, of regions R1, R2, and R3, region R1 is the hardest region. On the other hand, of regions R1, R2, and R3, region R3 is the softest region. Region R1 is located at the right end of the elastic member 151 and is positioned on the central axis of the elastic member 151. Region R2 is positioned to surround region R1. Region R3 is positioned to surround region R2. The left end face and outer circumferential face of the elastic member 151 are formed by region R3. On the right end face of the elastic member 1 5 1, region R 1 is located at the center, region R 2 is located around region R 1, and region R 3 is located around region R 2.

[0185] [ 0 0 8 7 ]

[0186] However, the positional relationship and number of regions with different hardnesses in the elastic member 1 5 1 are not limited to the example in Figure 2. The number of regions with different hardnesses in the elastic member 1 5 1 may be two, or it may be four or more. Also, for example, the hardness may differ among multiple regions obtained by dividing the elastic member 1 5 1 in the left-right direction (i.e., multiple regions having a cylindrical shape and being continuous with respect to each other in the left-right direction).

[0187] [ 0 0 8 8 ]

[0188] The opening / closing member 123 is provided in the hole 131a4 of the body 131a of the piston 131. The opening / closing member 123 includes a valve body 123a and a biasing member 123b. The valve body 123a has a substantially cylindrical shape that extends axially from the housing 101. The valve body 123a includes a head 123a1, a flange 123a2, a seal 123a3, and an internal passage 123a4.

[0189] [ 0 0 8 9 ]

[0190] The head !23a1 corresponds to the left end of the valve body !23a. The head !23a1 has, for example, a hemispherical shape. The flange 123a2 is located on the axially central side of the valve body 123a and is the portion where the outer diameter is enlarged. The outer circumferential surface of the flange 123a2 is slidable against the inner circumferential surface of the hole 131a4. The seal 123a3 is, for example, an O-ring. The seal 123a3 is formed in an annular shape extending in the circumferential direction of the valve body :L23a and is fitted to the outer circumferential surface of the flange 123a2. The seal !23a3 is pressed against the inner circumferential surface of the hole 131a4. As a result, the gap between the outer surface of flange 2 3 a 2 and the inner surface of hole 1 3 1 a 4 is sealed to the liquid. The internal flow path 1 2 3 a 4 is a flow path formed inside valve body 1 2 3 a. The internal flow path 1 2 3 a 4 connects the left side of flange 1 2 3 a 2 and the right side of flange 1 2 3 a 2 on the outer surface of valve body 1 2 3 a.

[0191] [ 0 0 9 0 ]

[0192] The biasing member 123b is, for example, a spring. The biasing member 123b is positioned between the cover 131c and the valve body 123a. The biasing member 23b is positioned so that its expansion and contraction direction is left-right, and is in a contracted state relative to its natural length. Therefore, the valve body 123a is biased to the left by the biasing member 23b.

[0193] [ 0 0 9 1 ]

[0194] The head 123a1 of the valve body 123a of the opening / closing member 123 is positioned to the right of the through hole 31a6 of the body 131a of the piston 131. The diameter of the head 123a1 of the valve body 123a is larger than the diameter of the through hole 31a6. The head 123a1 of the valve body 23a can contact the edge of the through hole 131a6.

[0195] [ 0 0 9 2 ]

[0196] In the example shown in Figure 2, the head 123a1 of valve body 23a is in contact with the edge of through hole 31a6. In this case, through hole 31a6 is closed by valve body 123a, and the space to the right of piston 132 in the first internal space S3 and the space to the right of piston 131 in the second fluid chamber S2 are closed (that is, brake fluid cannot flow between the space to the right of piston 132 in the first internal space S3 and the space to the right of piston 131 in the second fluid chamber S2).

[0197] [ 0 0 9 3 ]

[0198] On the other hand, when the head 123a of valve body 23a is separated from the edge of through hole 31a6, the through hole 131a6 is opened by valve body 123a, and the space to the right of piston 132 in the first internal space S3 and the space to the right of piston 131 in the second fluid chamber S2 are opened (that is, brake fluid can flow between the space to the right of piston 132 in the first internal space S3 and the space to the right of piston 131 in the second fluid chamber S2). In this way, by the valve body 123a opening and closing the through hole 31a6, the opening and closing member 123 opens and closes the space between the piston 132 and the space to the right of the first internal space S3.

[0199]

[0200] Furthermore, as described above, the outer circumferential surface of flange 123a2 is slidable relative to the inner circumferential surface of hole 131a4. As a result, valve body 23a can slide linearly in the axial direction of housing 101. In other words, valve body 23a is provided so as to be slidable linearly in the direction of opening and closing between the space to the right of piston 132 in the first internal space S3 and the space to the right of piston 131 in the second liquid chamber S2.

[0201] [ 0 0 9 5 ]

[0202] (Operation of the damping device)

[0203] Referring to Figures 2 to 4, the operation of the damping device 1〇〇 according to the first embodiment of the present invention will be described.

[0204] [ 0 0 9 6 ]

[0205] As described above, Figure 2 shows the damping device 100 under normal circumstances when brake operation is being performed, without anti-lock brake control or emergency automatic braking being activated. In this case, brake fluid is sent from the master cylinder 13 to the inside of the damping device 100 via port P4 as the brake operation is performed. As a result, the pressure in the space to the right of the piston 131 in the second fluid chamber S2 increases, causing the piston 131 to move to the left. Therefore, the projection 131b2 of the piston 131 pushes the valve body 121a of the opening / closing member 121 to the left, opening the through hole 113a. In other words, the opening / closing member 121 is in the open state, allowing brake fluid to flow between the first fluid chamber S1 and the second fluid chamber S2 through the through hole 113a.

[0206] [ 0 0 9 7 ]

[0207] Furthermore, in the example shown in Figure 2, the valve body ☐ 22a of the opening / closing member 122 is in contact with the edge of the through-hole 101f due to the biasing force from the biasing member 122b. In other words, the opening / closing member 122 is in the closed state, and brake fluid cannot flow between the first fluid chamber S1 and the master cylinder 13 through the through-hole ☐ 01f.

[0208] [ 0 0 9 8 ]

[0209] Under normal circumstances, when anti-lock brake control or emergency automatic braking is not being performed, and when the brakes are being applied, the brake fluid sent from the master cylinder 13 to the damping device 100 via port P4 is then sent to the wheel cylinder through port P2. Therefore, a braking force corresponding to the amount of brake operation is generated on the wheel 17.

[0210] [ 0 0 9 9 ]

[0211] Figure 3 shows the state of damping device 100 during anti-lock brake control. As described above, during anti-lock brake control, pump 36 is driven while the brakes are being applied.

[0212] [ 0 1 0 0 ]

[0213] During anti-lock brake control, the brakes are being applied, and as in normal operation, the pressure in the space to the right of the piston 131 in the second fluid chamber S2 increases, causing the piston 131 to move to the left. Therefore, the projection 131b2 of the piston 131 pushes the valve body 121a of the opening / closing member 121 to the left, opening the through hole 113a. In other words, the opening / closing member 121 becomes open, and brake fluid can flow between the first fluid chamber S1 and the second fluid chamber S2 through the through hole 113a.

[0214] [ 0 1 0 1 ]

[0215] Furthermore, during anti-lock brake control, the pump 3 6 is driven, and brake fluid is sent from the pump 3 6 to the inside of the damping device XX via port P !. Here, as described above, during anti-lock brake control, the opening / closing member 1 2 1 is in the open state, and brake fluid can flow between the first fluid chamber S 1 and the second fluid chamber S 2 through the through hole ! 1 3 a. Therefore, as shown by the dashed arrow in Figure 3, the brake fluid sent to the first fluid chamber S ! is sent from the first fluid chamber S ! to the first internal space S 3 of the piston 1 3 1 via the through hole 1 1 3 a. Therefore, the pressure in the space to the left of piston I32 in the first internal space S3 increases, pushing piston I32 to the right and moving to the right relative to piston 131. As a result, pressure is accumulated in the space to the right of piston 132 in the first internal space S3, and the pressure pulsation is attenuated. Furthermore, the force acting on piston 132 is absorbed by the biasing member 142. Thus, the pressure pulsation is also attenuated by the expansion and contraction of the biasing member 142 in conjunction with the sliding of piston 132 relative to piston 131.

[0216] [ 0 1 0 2 ]

[0217] Furthermore, during anti-lock brake control, the brake fluid sent from the first fluid chamber S1 to the first internal space S3 is also sent to the second internal space S4 of the piston 132. As a result, the pressure in the space to the left of the piston 133 in the second internal space S4 increases, and as shown by the solid arrow in Figure 3, the piston 133 is pushed to the right and moves to the right relative to the piston 132. Consequently, the elastic member 151 undergoes elastic deformation as it is pressed to the right by the right end face of the piston 133. In this way, the elastic member 151 undergoes elastic deformation in accordance with the sliding motion of the piston 133 relative to the piston 132. Therefore, the pressure pulsation is also dampened by the expansion and contraction of the elastic member 151 as the piston 133 slides against the piston 132.

[0218] [ 0 1 0 3 ]

[0219] During anti-lock brake control, the opening / closing member 122 opens and closes the gap between the first fluid chamber S1 and the master cylinder 13 in response to pressure changes in the first fluid chamber S1. For example, if the pressure in the first fluid chamber S1 is not very high during anti-lock brake control, the valve body 122a of the opening / closing member 122 will be in contact with the edge of the through-hole f due to the biasing force of the biasing member 122b. In other words, the opening / closing member 122 will be in a closed state, and brake fluid will not be able to flow between the first fluid chamber S1 and the master cylinder 13 through the through-hole f.

[0220] [ 0 1 0 4 ]

[0221] On the other hand, during anti-lock brake control, if the pressure in the first fluid chamber S1 rises to a certain level, the valve body 122a of the opening / closing member 122 overcomes the biasing force of the biasing member 22b and moves radially outward from the housing 101, causing the valve body 122a to separate from the through hole 101f. Therefore, the through hole 101f is opened, the opening / closing member 122 becomes open, and brake fluid can flow between the first fluid chamber S1 and the master cylinder 13 through the through hole 01f. Thus, the brake fluid sent from port P1 to the first fluid chamber S1 is gradually returned to the master cylinder 13 side through port P3.

[0222] [ 0 1 0 5 ]

[0223] Here, during the execution of anti-lock brake control, the opening / closing members 123 open and close in accordance with the sliding of piston 132 relative to piston 131. For example, during the execution of anti-lock brake control, if piston 132 has not moved significantly to the right relative to piston 131, and the pressure in the space to the right of piston 132 within the first internal space S3 is not very high, then the valve body 23a of the opening / closing member 123 will be in contact with the edge of the through hole 131a6 due to the biasing force of the biasing member 123b. In other words, brake fluid cannot flow through the through hole 131a6 between the space to the right of piston 132 within the first internal space S3 and the space to the right of piston 131 within the second fluid chamber S2.

[0224] [ 0 1 0 6 ]

[0225] On the other hand, during the execution of anti-lock brake control, when piston 132 moves to a certain extent to the right relative to piston 131, and the pressure in the space to the right of piston 132 within the first internal space S3 increases to a certain extent, the valve body 123a of the opening / closing member 123 moves to the right, overcoming the biasing force of the biasing member 123b, and the valve body 123a separates from the through hole 131a6. Therefore, the through hole 131a6 is opened, the opening / closing member 123 is in the open state, and brake fluid can flow through the through hole 131a6 between the space to the right of piston 132 within the first internal space S3 and the space to the right of piston 131 within the second fluid chamber S2. Therefore, as shown by the dashed arrow in Figure 3, brake fluid is discharged from the space to the right of the piston 132 in the first internal space S3, and the pressure in that space decreases. This allows for further pressure accumulation in the space to the right of the piston 132 in the first internal space S3, and this accumulation of pressure enhances the effect of attenuating pressure pulsations.

[0226] [ 0 1 0 7 ]

[0227] As shown in Figure 3, when the opening / closing member 123 is in the open position, the valve body 123a comes into contact with the surrounding member, the cover 131c. For example, in this case, the right end surface of the valve body 123a makes surface contact with the left end surface of the cover 131c. This allows the opening position of the opening / closing member 123 to be stably maintained.

[0228] [ 0 1 0 8 ]

[0229] Figure 4 shows the state of the damping device 100 during the execution of the emergency automatic braking system. As described above, during the execution of the emergency automatic braking system, the pump 36 is driven even when no brake operation is being performed.

[0230] [ 0 1 0 9 ]

[0231] During emergency automatic braking, no brake operation is performed, so brake fluid is not supplied from the master cylinder 13 to the damping device 100 via port P4. As a result, the biasing force of the biasing member 141 overcomes the pressure in the space to the right of the piston 131 in the second fluid chamber S2, and the piston 131 is pushed to the right by the biasing member 141 and moves to the right. Therefore, the projection I31b2 of the piston 131 separates from the valve body 121a of the opening / closing member 121, and the valve body 121a is pushed to the right by the biasing member 121b and moves to the right. As a result, the valve body 121a abuts against the edge of the through hole 113a, and the through hole 113a is closed by the valve body 121a. In other words, the opening / closing member 121 becomes closed, and brake fluid cannot flow between the first fluid chamber S1 and the second fluid chamber S2 through the through hole 13a.

[0232] [ 〇 1 1 〇 ]

[0233] Furthermore, during the execution of the emergency automatic brake, the pump 3 6 is driven, and brake fluid is sent from the pump 3 6 to the inside of the damping device 1 XX via port P !. Here, as described above, during the execution of the emergency automatic brake, the opening / closing member 1 2 1 is in a closed state, and brake fluid cannot flow between the first fluid chamber S ! and the second fluid chamber S 2 through the through hole 1 1 3 a. Therefore, the brake fluid sent to the first fluid chamber S 1 is not sent from the first fluid chamber S ! to the first internal space S 3 of the piston 1 3 1 via the through hole 1 1 3 a.

[0234] [ 0 1 1 1 ]

[0235] Therefore, during the execution of the emergency automatic brake, the pressure in the first fluid chamber S1 increases, pushing the valve body 122a of the opening / closing member 122 radially outward from the housing 101 and moving the valve body 122a away from the through hole 01f. Thus, the through hole 01f is opened, the opening / closing member 122 becomes open, and brake fluid can flow between the first fluid chamber S1 and the master cylinder 13 through the through hole 01f. Therefore, as shown by the dashed arrow in Figure 4, the brake fluid sent to the first fluid chamber S1 passes through hole 1Old and is discharged from port P3. Subsequently, the brake fluid discharged from port P3 is sent again to the damping device 10〇 via port P4, and then sent to the wheel cylinder through port P2. Thus, braking force is automatically generated on the wheel 17.

[0236] [ 0 1 1 2 ]

[0237] Here, during the execution of the emergency automatic brake, the opening / closing member 123 is in the closed state. Specifically, during the execution of the emergency automatic brake, the brake fluid sent to the first fluid chamber S1 is not sent from the first fluid chamber S1 to the first internal space S3 of the piston 131 through the through hole 113a, so there is no relative movement of piston 132 with respect to piston 131. Therefore, the pressure in the space to the right of piston 132 in the first internal space S3 does not increase, and the valve body 123a of the opening / closing member 123 is in contact with the edge of the through hole 31a6 due to the biasing force of the biasing member 123b. In other words, brake fluid cannot flow through the through-hole 131a6 between the space to the right of piston 132 in the first internal space S3 and the space to the right of piston 131 in the second fluid chamber S2.

[0238] [ 0 1 1 3 ]

[0239] (Effect of damping device)

[0240] The effects of the damping device 1〇〇 according to the first embodiment of the present invention will be described.

[0241] [〇 ! 1 4]

[0242] The damping device 100 comprises a first liquid chamber S1 communicating with the discharge side of the pump 36 and the master cylinder 13, a second liquid chamber S2 communicating with the first liquid chamber S1 and the master cylinder 13, a first opening / closing member (in the above example, opening / closing member 121) that opens and closes the space between the first liquid chamber S1 and the second liquid chamber S2, a first piston (in the above example, piston 131) slidably mounted in the second liquid chamber S2, a first internal space S3 formed inside the first piston and opening to the first liquid chamber S1 side, and a second piston (in the above example, piston 132) provided in the first internal space S3 and slidably mounted relative to the first piston. The device also includes a second opening / closing member (in the above example, opening / closing members 1, 2, and 3) that opens and closes the space in the first internal space S3 that is opposite to the first liquid chamber S1 relative to the second piston, and the space in the second liquid chamber S2 that is opposite to the first liquid chamber S1 relative to the first piston. Furthermore, when the pump 36 is driven while the brakes are being applied (in the above example, when anti-lock brake control is being performed), the first piston moves toward the first liquid chamber S1, causing the first opening / closing member to open, and the second opening / closing member opens and closes as the second piston slides toward the first piston. When the pump 36 is driven while the brakes are not being applied (in the above example, when the emergency automatic brake is being performed), the first piston moves toward the opposite side of the first liquid chamber S1, causing the first opening / closing member to close, and the second opening / closing member to close.

[0243] [ 0 1 1 5 ]

[0244] As a result, when the pump 36 is driven while the brakes are being applied, the brake fluid sent to the first fluid chamber S1 by the operation of the pump 36 is sent to the second internal space S3, thereby damping the pressure pulsation caused by the sliding of the second piston against the first piston. Here, in situations such as when anti-lock brake control is being performed, the noise generated by pressure pulsation tends to be a factor that impairs comfort. Therefore, in such situations, there is a high need to dampen pressure pulsation.

[0245] [ 0 1 1 6 ]

[0246] Furthermore, when the pump 36 is driven while the brakes are being applied, the second opening / closing member opens and closes in accordance with the sliding of the second piston relative to the first piston, thereby enhancing the effect of attenuating pressure pulsations by accumulating pressure in the space to the right of the second piston within the first internal space S3, as described above.

[0247] [ 0 1 1 7 ]

[0248] On the other hand, when pump 36 is driven while no brake operation is being performed, the brake fluid sent to the first fluid chamber S1 as a result of pump 36 being driven can be sent to the wheel cylinder without being sent to the first internal space S3. In situations such as when emergency automatic braking is being performed, there is a high need to quickly brake the vehicle in order to attenuate pressure pulsations. Therefore, in such situations, the vehicle can be quickly braked by sending the brake fluid to the wheel cylinder without sending it to the first internal space S3.

[0249] [〇 ! 1 8]

[0250] As described above, the damping device 1〇〇 can appropriately dampen the pressure pulsations of the hydraulic control unit 15.

[0251] [ 0 1 1 9 ]

[0252] In this specification, the side of the first liquid chamber S1 relative to the object may mean the side moving from the object toward the first liquid chamber S1, or the side on which the first liquid chamber S1 exists relative to the object. For example, in the above example, the side of the first liquid chamber S1 relative to piston 131 corresponds to the left side. Also, the side opposite to the first liquid chamber S1 relative to the object may mean the side opposite to the side moving from the object toward the first liquid chamber S1, or the side opposite to the side on which the first liquid chamber S1 exists relative to the object. For example, in the above example, the side opposite to the first liquid chamber S1 relative to piston 31 corresponds to the right side.

[0253] [ 0 1 2 0 ]

[0254] Furthermore, the damping device 100 includes a biasing member 42 that biases the second piston (piston 132 in the above example) toward the first liquid chamber S1. This enhances the effect of damping pressure pulsations caused by the sliding of the second piston relative to the first piston. However, the biasing member 142 may be omitted from the damping device 100.

[0255] [ 0 1 2 1 ]

[0256] Furthermore, the damping device 100 includes a second internal space S4 formed inside the second piston (piston 132 in the above example) and opening to the first liquid chamber S1 side, a third piston (piston 133 in the above example) provided in the second internal space S4 and slidable relative to the second piston, and a first elastic member (elastic member 151 in the above example) provided in the second internal space S4 on the side opposite to the first liquid chamber S1 relative to the third piston 133, and elastically deforms as the third piston slides relative to the second piston. As a result, when the pump 36 is driven while the brakes are being applied, pressure pulsation can be dampened not only by the sliding of the second piston relative to the first piston, but also by the expansion and contraction of the elastic member 151. However, the first elastic member may be omitted from the damping device 100.

[0257] [ 0 1 2 2 ]

[0258] Furthermore, in the damping device 100, the first elastic member (elastic member 151 in the above example) includes multiple regions with different hardnesses (regions R1, R2, and R3 in the above example). Here, the effect of damping pressure pulsations by the elastic member 151 varies depending on the hardness of the elastic member 151. Also, the hardness of the elastic member 151 that is suitable (i.e., effective) for damping pressure pulsations may change depending on the state of the pressure pulsations (e.g., period, amplitude, etc.). Therefore, by providing multiple regions R1, R2, and R3 with different hardnesses in the elastic member 151, pressure pulsations can be effectively damped in any of these regions, regardless of the state of the pressure pulsations. Thus, the effect of damping pressure pulsations can be enhanced as the elastic member 151 expands and contracts. However, the first elastic member described above does not necessarily have to include multiple regions with different thicknesses.

[0259] [ 0 1 2 3 ]

[0260] Furthermore, the damping device 100 includes a valve body 123a that opens and closes the space in the first internal space S3 opposite to the first liquid chamber S1 relative to the second piston (piston 132 in the above example) and the space in the second liquid chamber S2 opposite to the first liquid chamber S1 relative to the first piston (piston 131 in the above example). When the second opening and closing member is in the open state, the valve body 123a comes into contact with the surrounding member (cover 131c in the above example). This allows the open state of the second opening and closing member to be stably maintained. However, when the second opening and closing member is in the open state, the valve body 123a does not need to come into contact with the surrounding member.

[0261] [ 0 1 2 4 ]

[0262] Furthermore, the damping device 100 includes a second opening / closing member (in the above example, opening / closing member 23) which includes a valve body 123a that opens and closes the space in the first internal space S3 that is opposite to the first liquid chamber S1 with respect to the second piston (in the above example, piston 32) and the space in the second liquid chamber S2 that is opposite to the first liquid chamber S1 with respect to the first piston (in the above example, piston 131). The valve body 123a is provided so as to be linearly slidable in the direction of opening and closing the space in the first internal space S3 that is opposite to the first liquid chamber S1 with respect to the second piston and the space in the second liquid chamber S2 that is opposite to the first liquid chamber S1 with respect to the first piston. This prevents the valve body 123a from moving in directions other than the direction of opening and closing between the two spaces (for example, in the radial direction of the housing 101 in the above example), thus enabling stable opening and closing of the through hole 31a6 by the valve body 123a. However, the valve body 123a does not necessarily have to be provided so as to be able to slide linearly in the direction of opening and closing between the two spaces.

[0263] [ 0 1 2 5 ]

[0264] Furthermore, the damping device 100 includes a third opening / closing member (in the above example, opening / closing member 22) that opens and closes the gap between the first fluid chamber S1 and the master cylinder 13 in response to pressure changes in the first fluid chamber S1. As a result, as shown in Figure 2, in normal operation when anti-lock brake control or emergency automatic braking is not being performed, it is possible to prevent brake fluid from flowing between the first fluid chamber S1 and the master cylinder 13 through the through hole 1f. Therefore, it is possible to suppress the supply of brake fluid from the master cylinder 13 to the first fluid chamber S1 via port P3 when the brakes are applied. Therefore, under normal circumstances, it is possible to suppress the unnecessary sending of a portion of the brake fluid supplied from the master cylinder 13 to the first internal space S3. This suppresses, for example, a decrease in responsiveness when generating braking force on the wheel 17 through brake operation. However, the third opening / closing member may be omitted from the damping device 100.

[0265] [ 0 1 2 6 ]

[0266] Second Embodiment >

[0267] A second embodiment of the present invention will be described with reference to Figures 5 to 7.

[0268] [ 0 1 2 7 ]

[0269] In the second embodiment, the difference from the first embodiment described above is that the damping device L〇〇 is replaced with damping device 2〇〇. Other aspects of the brake system 1 are the same as in the first embodiment described above, so a description is omitted.

[0270] [ 0 1 2 8 ]

[0271] (Configuration of the damping device)

[0272] Referring to Figure 5, the details of the configuration of the damping device 200 according to the second embodiment of the present invention will be described.

[0273] [ 0 1 2 9 ]

[0274] Figure 5 is a cross-sectional view showing the schematic configuration of the damping device 200. Specifically, Figure 5 shows the damping device 200 under normal circumstances when brake operation is being performed, and when anti-lock brake control or emergency automatic braking is not being performed. Note that the damping device 200 shown in Figure 5 is merely one example of a damping device according to the present invention, and various modifications to the example in Figure 5, as described later, are also included in the damping device according to the present invention.

[0275] [ 0 1 3 0 ]

[0276] As shown in Figure 5, the damping device 200 comprises a housing 201, a cover 211, a cover 212, a valve seat 213, an opening / closing member 221, an opening / closing member 222, an opening / closing member 223, a piston 231, a piston 232, a biasing member 241, a biasing member 242, and an elastic member 251. Note that the opening / closing members 221, 222, 223, piston 231, and piston 232 correspond to examples of the first opening / closing member, third opening / closing member, second opening / closing member, first piston, and second piston according to the present invention.

[0277] [ 0 1 3 1 ]

[0278] The housing 201 is formed in a cylindrical shape with a hollow space inside. In Figure 5, the damping device 200 is shown such that the axial direction of the housing 201 is the left-right direction. Hereafter, the left-right direction in the drawings will also be simply referred to as the left-right direction. Note that the left-right direction in Figures 6 and 7, which will be described later, coincides with the left-right direction in Figure 5.

[0279] [ 0 1 3 2 ]

[0280] The hollow space inside housing 2 0 1 opens on the left side of housing 2 0 1 and is closed on the right side. The inner circumferential surface 2 0 1a of housing 2 0 1 is formed in a substantially cylindrical shape.

[0281] [ 0 1 3 3 ]

[0282] Of the hollow space inside housing 2 0 1, the space where the cover 2 1 1, described later, is placed corresponds to the first liquid chamber S 1. Of the hollow space inside housing 2 0 1, the space to the right of the cover 2 1 1, described later, corresponds to the second liquid chamber S 2.

[0283] [0 1 3 4] The ports P1, P2, P3, and P4 described above are formed on the outer circumferential surface of the housing 201.

[0284] [ 0 1 3 5 ]

[0285] Port P1 communicates with the first liquid chamber S1 through a through-hole 201b formed in the housing 201. The through-hole 201b extends radially in the housing 201 and opens to the inner circumferential surface 20la.

[0286] [ 0 1 3 6 ]

[0287] Port P2 communicates with the second liquid chamber S2 through a through-hole 201c formed in the housing 201. The through-hole 201c extends radially in the housing 201 and opens to the inner circumferential surface 20a.

[0288] [ 0 1 3 7 ]

[0289] Port P3 communicates with the first liquid chamber S1 through a hole 201d formed in the housing 201. For example, hole 201d is located outside the inner circumferential surface 201a in the radial direction of the housing 201 and has a cylindrical shape that extends radially across the housing 201. On the outer circumferential surface side of hole 201, a groove 201e is provided, which is formed in an annular shape coaxial with hole 201 and whose inner diameter expands. An annular cover 212 is provided in groove 201e. The outer circumferential surface of cover 212 is fitted into the inner circumferential surface of groove 201e. This corresponds to the center of cover 212. On the inner circumferential surface 2〇1a side of hole 201d, through hole 201f connects hole 201d and liquid chamber S!

[0290]

[0291] Port P4 communicates with the second liquid chamber S2 through a through-hole 2〇!g formed in the housing 201. The through-hole 2〇1g extends radially in the housing 201 and opens to the inner circumferential surface 2〇!a.

[0292] [ 0 1 3 9 ]

[0293] The first liquid chamber S1 is connected to the discharge side of the pump 36 via port P1 and to the master cylinder 13 via port P3. The second liquid chamber S2 is connected to the first liquid chamber S1 and to the master cylinder 13 via port P4.

[0294] [ 0 1 4 0 ]

[0295] Cover 211 is provided in the first liquid chamber S1. Cover 211 has a substantially cylindrical shape that extends axially from housing 201. Cover 211 is positioned coaxially with housing 201, for example. The outer circumferential surface of cover 21I is fitted onto the inner circumferential surface 2Ola. Cover 211 is fixed to housing 201. Cover 211 is provided with a hole 2Ila, a groove 211b, a through hole 211c, and a through hole 211d.

[0296] [ 0 1 4 1 ]

[0297] Hole 211a is located coaxially with cover 211, opening on the right side of cover 211 and closing on the left side. Hole 2Ila has a substantially cylindrical shape and extends axially along cover 211. Groove 211b is formed to the right of hole 211a in an annular shape coaxial with hole 211a, and is a portion where the inner diameter expands. Through hole 211c connects hole 211a and through hole 2O1b. Through hole 211c extends radially along housing 20I, for example. Through hole 211d connects hole 2Ila and through hole 201f. The through hole 2 1 1 d is, for example, in the radial direction of housing 2 〇 1

[0298] [ 0 1 4

[0299] Opening / closing parts

[0300]

[0301] It is provided in the opening / closing member 221, which includes a valve body 221a and a biasing member 221b. The valve body 221a is, for example, spherical in shape. The biasing member 221b is, for example, a spring. The biasing member 221b is positioned between the bottom surface of the hole 211a (i.e., the right-facing surface) and the valve body 221a. The biasing member 221b is positioned so that its expansion and contraction direction is left-right, and is in a contracted state relative to its natural length. Therefore, the valve body 221a is biased to the right by the biasing member 221b.

[0302] [0 1 4 3] The valve seat 2 1 3 is provided in the groove 2 1 1 b of the cover 2 1 I. The valve seat 2 1 3 is formed in an annular shape coaxial with the housing 2 0 1. The valve seat 2 1 3 is provided with a through hole 2 1 3 a that penetrates the valve seat 2 1 3 in the left-right direction. The outer circumferential surface of the valve seat 2 1 3 is fitted into the inner circumferential surface of the groove 2 1 1 b. The valve seat 2 1 3 is fixed to the cover 2 1 1.

[0303] [ 0 1 4 4 ]

[0304] The valve body 221a of the opening / closing member 221 is positioned to the left of the through hole 213a of the valve seat 213. The diameter of the valve body 221a is larger than the diameter of the through hole 213a. The valve body 221a can contact the edge of the through hole 213a.

[0305] 0 1 4 5 ]

[0306] In the example shown in Figure 5, the valve body 221a is separated from the edge of the through hole 213. In this case, the through hole 213a is opened by the valve body 221a, and the space between the first fluid chamber S1 and the second fluid chamber S2 is opened (that is, brake fluid can flow between the first fluid chamber S1 and the second fluid chamber S2).

[0307] [ 0 1 4 6 ]

[0308] On the other hand, when the valve body 221a comes into contact with the edge of the through hole 213a, the through hole 213a is closed by the valve body 221a, and the space between the first fluid chamber S1 and the second fluid chamber S2 is closed (that is, brake fluid cannot flow between the first fluid chamber S1 and the second fluid chamber S2). In this way, the valve body 221a opens and closes the through hole 213a of the valve seat 213, thereby opening and closing the space between the first fluid chamber S1 and the second fluid chamber S2.

[0309] [ 0 1 4 7 ]

[0310] The opening / closing member 222 is provided in the hole 2Old of the housing 201. The opening / closing member 222 includes a valve body 222a and a biasing member 222b. The valve body 222a is, for example, spherical in shape. The biasing member 222b is, for example, a spring. The biasing member 222b is positioned between the cover 212 and the valve body 222a. The biasing member 222b is positioned so that its expansion and contraction direction is radial to the housing 201, and is in a contracted state relative to its natural length. Therefore, the valve body 222a is biased toward the through hole 201f by the biasing member 222b.

[0311] [ 0 1 4 8 ]

[0312] The valve body 222a of the opening / closing member 222 is positioned radially outward of the housing 201 relative to the through hole 201f. The diameter of the valve body 222a is greater than the diameter of the through hole 201f. The valve body 222a can abut against the edge of the through hole 201f.

[0313]

[0149]

[0314] In the example shown in Figure 5, the valve body 222a is in contact with the edge of the through hole 201f. In this case, the through hole 201f is closed by the valve body 222a, and the space between the first fluid chamber S1 and the port P3 is closed (i.e., brake fluid cannot flow between the first fluid chamber S1 and the master cylinder 13).

[0315] [ 0 1 5 0 ]

[0316] On the other hand, when the valve body 222a is separated from the edge of the through hole 201f, the through hole 201f is opened by the valve body 222a, and the space between the first fluid chamber S1 and the port P3 is opened (that is, brake fluid can flow between the first fluid chamber S1 and the master cylinder 13). In this way, the valve body 222a opens and closes the through hole 201f, and the opening / closing mechanism 5 member 222 opens and closes the space between the first fluid chamber S1 and the master cylinder 13.

[0317] [ 0 1 5 1 ]

[0318] The piston 231 is provided in the second fluid chamber S2. The piston 231 has a substantially cylindrical shape that extends axially from the housing 201. The piston 231 is positioned, for example, coaxially with the housing 201. The piston 231 is provided so as to be slidable in the axial direction within the second fluid chamber S2. The piston 231 includes a body 231a, a cover 231b, and a cover 231c.

[0319] [ 0 1 5 2 ]

[0320] The main body 231a forms the general shape of the piston 231. The main body 231a has a substantially cylindrical shape that extends axially from the housing 201. The main body 231a is arranged coaxially with, for example, the housing 201. The outer circumferential surface of the main body 231a is slidable with respect to the inner circumferential surface 201a. The main body 231a is provided with a seal 231al, a hole 231a2, a groove 231a3, a hole 231a4, a groove 231a5, and a through hole 231a6.

[0321] [ 0 1 5 3 ]

[0322] Seal 231a1 is, for example, a ring. Seal 231a1 is formed in an annular shape extending circumferentially from body 231a and is fitted onto the outer circumferential surface of body 231a. Seal 23lai is pressed against the inner circumferential surface 2Ola. This seals the gap between the outer circumferential surface of body 231a and the inner circumferential surface 2Ola to a liquid-tight seal. In the example in Figure 5, there are two seals 231a1. However, the number of seals 231a1 may be one, three or more, etc.

[0323] [ 0 1 5 4 ]

[0324] Hole 231a2 is positioned coaxially with the main body 231a, opening to the left side of the main body 231a and closing to the right side. Hole 231a2 has a substantially cylindrical shape that extends axially along the main body 231a. As will be described later, hole 231a2 opens to the first liquid chamber S1 side through the through hole 231bl of the cover 231b. In other words, hole 231a2 corresponds to the first internal space S3 formed inside the piston 231 and opening to the first liquid chamber S1 side.

[0325] [ 0 1 5 5 ]

[0326] Groove 231a3 is formed to the left of hole 231a2, coaxially with hole 231a2, and is an annular shape in which the inner diameter expands. Cover 231b is fretted into this groove 231a3.

[0327] [ 0 1 5 6 ]

[0328] The cover 231b is fixed to the groove 231a3 of the main body 231a. The cover 231b is formed in a roughly disc shape coaxial with the housing 201. The outer surface of the cover 231b is fitted to the inner surface of the groove 231a3. The cover 231b is provided with a through hole 231b! and a projection 231b2.

[0329] [ 0 1 5 7 ]

[0330] The through-hole 231bl penetrates the cover 231b in the left-right direction. Therefore, the through-hole 231b1 connects the first internal space S3 of the piston 231 with the first liquid chamber S!. For example, multiple through-holes 231b1 are provided at intervals in the circumferential direction of the cover 231b. However, the number of through-holes 231b1 may be just one.

[0331] [ 0 1 5 8 ]

[0332] The projection 231b2 protrudes to the left from the left end face of the cover 231b. The projection 231b2 is positioned coaxially with the cover 231b. In the example in Figure 5, the tip (i.e., the left end) of the projection 231b2 is located to the left of the through hole 213a. Therefore, the through hole 213a is opened by the valve body 221a being pushed to the left by the projection 231b2.

[0333]

[0159]

[0334] The hole 231a4 of the main body 231a is positioned coaxially with the main body 231a, opens to the right side of the main body 231a, and closes to the left side. The hole 231a4 has a substantially cylindrical shape that extends in the axial direction of the main body 231a.

[0335] [ 0 1 6 0 ]

[0336] Groove 231a5 is formed to the right of hole 231a4, coaxially with hole 231a4, and is an annular shape in which the inner diameter expands. Cover 231c is fitted into this groove 231a5.

[0337] [ 0 1 6 1 ]

[0338] The cover 231c is fixed to the groove 231a5 of the main body 231a. The cover 231c is formed in a substantially annular shape coaxial with the housing 2〇1. The outer surface of the cover 231c is fitted to the inner surface of the groove 231a5.

[0339] [ 0 1 6 2 ]

[0340] The through hole 231a6 is located on the left side of hole 231a4. The through hole 231a6 connects hole 231a4 to the first internal space S3 of piston 231.

[0341] [ 0 1 6 3 ]

[0342] The biasing member 241 is, for example, a spring. The biasing member 241 is positioned between the right side of the cover 211 and the cover 231b of the piston 231. The biasing member 241 is positioned so that its extension and contraction direction is left-right, and is in a contracted state relative to its natural length. Therefore, the piston 231 is biased to the right by the biasing member 241.

[0343]

[0164]

[0344] Piston 232 is provided in the first internal space S3 of piston 231. Piston 232 has a substantially cylindrical shape that extends axially from the housing 201. Piston 232 is positioned, for example, coaxially with the housing 201. Piston 232 is provided so as to be axially slidable in the first internal space S3. That is, piston 232 is provided so as to be slidable relative to piston 231. Piston 232 includes a body 232a and a cover 232b.

[0165]

[0345] The main body 232a forms the general shape of the piston 232. The main body 232a has a substantially cylindrical shape that extends axially from the housing 201. The main body 232a is arranged coaxially with the housing 201, for example. The outer circumferential surface of the main body 232a is slidable against the inner circumferential surface of the hole 231a2 of the piston 231. The main body 232a is provided with a seal 232a1, a hole 232a2, and a through hole 232a3.

[0346]

[0166]

[0347] Seal 232a1 is, for example, an O-ring. Seal 232a1 is formed in an annular shape extending circumferentially from the main body 232a and is fitted onto the outer circumferential surface of the main body 232a. Seal 232a1 is pressed against the inner circumferential surface of the hole 231a2 of the piston 231. This seals the gap between the outer circumferential surface of the piston 232 and the inner circumferential surface of the hole 231a2 of the piston 231 in a liquid-tight seal. In the example in Figure 5, there are two seals 232a1. However, there may be one seal 232a1 or three or more seals 232a1.

[0348] [ 0 1 6 7 ]

[0349] Hole 232a2 is positioned coaxially with the main body 232a, opening on the right side of the main body 232a and closing on the left side. Hole 232a2 has a roughly cylindrical shape that extends in the axial direction of the main body 232a. A through hole 232a3 is provided in the center of the bottom surface of hole 232a2 (i.e., the side facing to the right). The through hole 232a3 penetrates the main body 232a in the left-right direction. As a result, hole 232a2 opens to the liquid chamber S1 side through the through hole 232a3. In other words, hole 232a2 is formed inside piston 232 and corresponds to the second internal space S4 that opens to the liquid chamber S1 side. Note that the edge of through hole 232a3 protrudes to the right.

[0350] [ 0 1 6 8 ]

[0351] Cover 232b is fixed to the right side of the inner circumferential surface of hole 232a2 in the main body 232a. Cover 232b is formed in a roughly disc shape coaxial with housing 201. The outer circumferential surface of cover 232b is fitted into the inner circumferential surface of hole 232a2. A through hole 232b1 is provided in the center of cover 232b. The through hole 232b1 penetrates cover 232b in the left-right direction. The edge of the through hole 232b1 protrudes to the left.

[0352]

[0169]

[0353] The biasing member 242 is, for example, a spring. The biasing member 242 is provided in the first internal space S3 of the piston 231. The biasing member 242 is positioned between the bottom surface of the hole 231a2 (i.e., the side facing left) and the cover 232b of the piston 232. The biasing member 242 is positioned so that its extension and contraction direction is left-right, and is in a contracted state relative to its natural length. Therefore, the piston 232 is biased to the left by the biasing member 242.

[0354] [ 0 1 7 0 ]

[0355] The elastic member 251 is provided in the second internal space S4 of the piston 232. The elastic member 251 has a cylindrical shape that extends axially from the housing 201. The elastic member 251 is positioned coaxially with the housing 201, for example. For example, the outer circumferential surface of the elastic member 251 is fitted into the inner circumferential surface of the hole 232a2 of the piston 232. The elastic member 251 is also sandwiched in the left-right direction between the bottom surface of the hole 232a2 of the piston 232 (i.e., the surface facing the right) and the cover 232b. For example, the entire left surface of the elastic part is within the hole 2 of the piston 232

[0356]

[0357] The bottom surface of 3 2 a 2 (i.e., the side facing to the right) is in contact with the cover 2 3 2 b, and the entire right surface of the elastic member 2 5 1 is in contact with the cover 2 3 2 b.

[0358] [ 0 1 7 1 ]

[0359] The elastic member 251 is formed of a material with a high elastic limit, such as rubber. A hole 251a is formed inside the elastic member 251. The hole 251a is a through hole that penetrates the elastic member 251 from left to right. However, the hole 251a only needs to open on the left side. For example, the hole 251a may open on the left side of the elastic member 251 but be closed on the right side. Also, the elastic member 251 may be cylindrical, but does not have to be cylindrical.

[0360] [ 0 1 7 2 ]

[0361] The opening / closing member 223 is provided in the hole 231a4 of the body 231a of the piston 231. The opening / closing member 223 includes a valve body 223a and a biasing member 223b. The valve body 223a has a substantially cylindrical shape that extends axially from the housing 201. The valve body 223a includes a head 223a1, a flange 223a2, a seal 223a3, and an internal passage 223a4.

[0362] [ 0 1 7 3 ]

[0363] The head 223a1 corresponds to the left end of the valve body 223a. The head 223a1 has, for example, a hemispherical shape. The flange 223a2 is located on the axially central side of the valve body 223a and is the portion where the outer diameter is enlarged. The outer circumferential surface of the flange 223a2 is slidable against the inner circumferential surface of the hole 231a4. The seal 223a3 is, for example, an O-ring. The seal 223a3 is formed in an annular shape extending in the circumferential direction of the valve body 223a and is fitted to the outer circumferential surface of the flange 223a2. The seal 223a3 is pressed against the inner circumferential surface of the hole 231a4. As a result, the gap between the outer surface of flange 223a2 and the inner surface of hole 231a4 is sealed to the liquid. The internal flow path 223a4 is a flow path formed inside valve body 223a. The internal flow path 223a4 connects the left side of flange 223a2 and the right side of the outer surface of valve body 223a.

[0364] [ 0 1 7 4 ]

[0365] The biasing member 223b is, for example, a spring. The biasing member 223b is positioned between the cover 231c and the valve body 223a. The biasing member 223b is positioned so that its expansion and contraction direction is left-right, and is in a contracted state relative to its natural length. Therefore, the valve body 223a is biased to the left by the biasing member 223b.

[0366] [ 0 1 7 5 ]

[0367] The head 223al of the valve body 223a of the opening / closing member 223 is positioned to the right of the through hole 231a6 of the body 231a of the piston 231. The diameter of the head 223a1 of the valve body 223a is larger than the diameter of the through hole 231a6. The head 223a1 of the valve body 223a can contact the edge of the through hole 231a6.

[0368] [ 0 1 7 6 ]

[0369] In the example shown in Figure 5, the head 223a1 of the valve body 223a is in contact with the edge of the through hole 231a6. In this case, the through hole 231a6 is closed by the valve body 223a, and the space to the right of the piston 232 within the first internal space S3© and the space to the right of the piston 231 within the second fluid chamber S2 are closed (that is, brake fluid cannot flow between the space to the right of the piston 232 within the first internal space S3 and the space to the right of the piston 231 within the second fluid chamber S2).

[0370] [ 0 1 7 7 ]

[0371] On the other hand, when the head 223a1 of the valve body 223a is separated from the edge of the through hole 231a6, the through hole 231a6 is opened by the valve body 223a, and the space to the right of the piston 232 in the first internal space S3 and the space to the right of the piston 231 in the second fluid chamber S2 are opened (that is, brake fluid can flow between the space to the right of the piston 232 in the first internal space S3 and the space to the right of the piston 231 in the second fluid chamber S2). In this way, by the valve body 223a opening and closing the through hole 231a6, the opening and closing member 223 opens and closes the space to the right of the piston 232 in the first internal space S3 and the space to the right of the piston 231 in the second liquid chamber S2.

[0372] [ 0 1 7 8 ]

[0373] Furthermore, as described above, the outer circumferential surface of flange 223a2 is slidable relative to the inner circumferential surface of hole 231a4. As a result, valve body 223a can slide linearly in the axial direction of housing 201. In other words, valve body 223a is provided so as to be slidable linearly in the direction of opening and closing between the space to the right of piston 232 in the first internal space S3 and the space to the right of piston 231 in the second liquid chamber S2.

[0374]

[0179]

[0375] (Operation of the damping device)

[0376] Referring to Figures 5 to 7, the operation of the damping device 200 according to the second embodiment of the present invention will be described.

[0377] [ 0 1 8 0 ]

[0378] As described above, Figure 5 shows the damping device 200 under normal circumstances when brake operation is being performed, without anti-lock brake control or emergency automatic braking being activated. In this case, brake fluid is sent from the master cylinder 13 to the inside of the damping device 200 via port P4 as the brake operation is performed. As a result, the pressure in the space to the right of the piston 231 in the second fluid chamber S2 increases, causing the piston 23I to move to the left. Therefore, the projection 231b2 of the piston 231 pushes the valve body 221a of the opening / closing member 22I to the left, opening the through hole 213a. In other words, the opening / closing member 2 2 ! is in the open state, allowing brake fluid to flow between the first fluid chamber S 1 and the second fluid chamber S 2 through the through hole 2 1 3 a.

[0379] [ 0 1 8 1 ]

[0380] Furthermore, in the example shown in Figure 5, the valve body 222a of the opening / closing member 222 is in contact with the edge of the through hole 201f due to the biasing force from the biasing member 222b. In other words, the opening / closing member 222 is in the closed state, and brake fluid cannot flow between the first fluid chamber S1 and the master cylinder 13 through the through hole 201f.

[0381] [ 0 1 8 2 ]

[0382] Under normal circumstances, when anti-lock brake control or emergency automatic braking is not being performed, and when the brakes are being applied, the brake fluid sent from the master cylinder 13 to the damping device 200 via port P4 is then sent to the wheel cylinder via port P2. Therefore, a braking force corresponding to the amount of brake operation is generated on the wheel 17.

[0383] [ 0 1 8 3 ]

[0384] Figure 6 shows the state of damping device 200 during anti-lock brake control. As described above, during anti-lock brake control, pump 36 is driven while the brakes are being applied.

[0385] [ 0 1 8 4 ]

[0386] During anti-lock brake control, since the brakes are being applied, the pressure in the space to the right of the piston 231 in the second fluid chamber S2 increases, just as in normal operation, causing the piston 231 to move to the left. Therefore, the projection 231b2 of the piston 231 pushes the valve body 221a of the opening / closing member 221 to the left, opening the through hole 213a. In other words, the opening / closing member 221 becomes open, and brake fluid can flow between the first fluid chamber S1 and the second fluid chamber S2 through the through hole 213a.

[0387] [ 0 1 8 5 ]

[0388] Furthermore, during anti-lock brake control, the pump 3 6 is driven, and brake fluid is sent from the pump 3 6 to the inside of the damping device 2 XX via port P !. Here, as described above, during anti-lock brake control, the opening / closing member 2 2 1 is in the open state, and brake fluid can flow between the first fluid chamber S 1 and the second fluid chamber S 2 through the through hole 2 1 3 a. Therefore, as shown by the dashed arrow in Figure 6, once the fluid is sent to the first fluid chamber S 1, it flows through the through hole 2 1 3 a to the piston 2 3 1.

[0389]

[0390] It is sent to the first internal space S3. As a result, the pressure in the space to the left of piston 232 in the first internal space S3 increases, pushing piston 232 to the right and moving to the right relative to piston 231. This causes pressure to accumulate in the space to the right of piston 232 in the first internal space S3, thereby dampening the pressure pulsation. Furthermore, the force acting on piston 232 is absorbed by the biasing member 242. Therefore, the pressure pulsation is also dampened by the expansion and contraction of the biasing member 242 in conjunction with the sliding of piston 232 relative to piston 231.

[0391] [ 0 1 8 6 ]

[0392] Furthermore, during anti-lock brake control, the brake fluid sent from the first fluid chamber S1 to the first internal space S3 is also sent to the second internal space S4 of the piston 232. As described above, the second internal space S4 is provided with a cylindrical elastic member 251 having a hole 251a. Therefore, the brake fluid sent to the second internal space S4 of the piston 232 is sent into the hole 251a of the elastic member 251. As a result, the pressure in the hole 251a increases, and the elastic member 251 undergoes elastic deformation, causing its inner surface to stretch outward and the volume of the hole 251a to expand, as shown by the solid arrow in Figure 6. Subsequently, in response to the pressure fluctuations in hole 251a, the elastic member 251 deforms such that its inner surface repeatedly expands and contracts. This also dampens the pressure pulsation.

[0393] [ 0 1 8 7 ]

[0394] During anti-lock brake control, the opening / closing member 222 opens and closes the gap between the first fluid chamber S1 and the master cylinder 13 in response to pressure changes in the first fluid chamber S1. For example, if the pressure in the first fluid chamber S1 is not very high during anti-lock brake control, the valve body 222a of the opening / closing member 222 will be in contact with the edge of the through hole 201f due to the biasing force of the biasing member 222b. In other words, the opening / closing member 222 will be in a closed state, and brake fluid will not be able to flow between the first fluid chamber S1 and the master cylinder 13 through the through hole 201f.

[0395] [ 0 1 8 8 ]

[0396] On the other hand, during anti-lock brake control, if the pressure in the first fluid chamber S1 rises to a certain level, the valve body 222a of the opening / closing member 222 overcomes the biasing force of the biasing member 222b and moves radially outward from the housing 201, causing the valve body 222a to separate from the through hole 201f. Therefore, the through hole 20f is opened, the opening / closing member 222 becomes open, and brake fluid can flow between the first fluid chamber S1 and the master cylinder 13 through the through hole 20f. Thus, the brake fluid sent from port P1 to the first fluid chamber S1 is gradually returned to the master cylinder 13 side through port P3.

[0397] [ 0 1 8 9 ]

[0398] Here, during the execution of anti-lock brake control, the opening / closing member 223 opens and closes in accordance with the sliding of piston 232 relative to piston 231. For example, during the execution of anti-lock brake control, if piston 232 has not moved significantly to the right relative to piston 231, and the pressure in the space to the right of piston 232 within the first internal space S3 is not very high, then the valve body 223a of the opening / closing member 223 will be in contact with the edge of the through hole 231a6 due to the biasing force of the biasing member 223b. In other words, brake fluid cannot flow through the through-hole 231a6 between the space to the right of piston 232 in the first internal space S3 and the space to the right of piston 231 in the second fluid chamber S2.

[0399] [ 0 1 9 0 ]

[0400] On the other hand, during the execution of anti-lock brake control, when piston 232 moves to the right relative to piston 231 to a certain extent, and the pressure in the space to the right of piston 232 within the second internal space S3 increases to a certain extent, the valve body 223a of the opening / closing member 223 moves to the right, overcoming the biasing force of the biasing member 223b, and the valve body 223a separates from the through hole 231a6. Therefore, the through hole 231a6 is opened, the opening / closing member 223 is in an open state, and brake fluid can flow through the through hole 231a6 between the space to the right of piston 232 within the second internal space S3 and the space to the right of piston 231 within the second fluid chamber S2. Therefore, as shown by the dashed arrow in Figure 6, brake fluid is discharged from the space to the right of the piston 232 in the first internal space S3, and the pressure in that space decreases. This allows for further pressure accumulation in the space to the right of the piston 232 in the first internal space S3, and this accumulation of pressure enhances the effect of attenuating pressure pulsations.

[0401] [ 0 1 9 1 ]

[0402] As shown in Figure 6, when the opening / closing member 223 is in the open position, the valve body 223a comes into contact with the surrounding member, the cover 231c. For example, in this case, the right end surface of the valve body 223a makes surface contact with the left end surface of the cover 231c. This allows the opening / closing member 223 to be stably maintained in the open position.

[0403] [ 0 1 9 2 ]

[0404] Figure 7 shows the state of the damping device 200 during the execution of the emergency automatic braking system. As described above, during the execution of the emergency automatic braking system, the pump 36 is driven even when no brake operation is being performed.

[0405]

[0193]

[0406] During emergency automatic braking, no brake operation is performed, so brake fluid is not supplied from the master cylinder 13 to the damping device 200 via port P4. As a result, the biasing force of the biasing member 241 overcomes the pressure in the space to the right of the piston 231 in the second fluid chamber S2, and the piston 231 is pushed to the right by the biasing member 241 and moves to the right. Therefore, the projection 231b2 of the piston 231 separates from the valve body 221a of the opening / closing member 221, and the valve body 221a is pushed to the right by the biasing member 221b and moves to the right. As a result, the valve body 221a abuts against the edge of the through hole 213a, and the through hole 213a is closed by the valve body 221a. In other words, the opening / closing member 221 is in the closed state, and brake fluid cannot flow between the first fluid chamber 2 and the through hole 213a. During braking, the pump 36 is driven, and brake fluid is sent into the damping device 200 via the pump 3. Here, while the automatic braking described above is in operation, the opening / closing member 221 is in a closed state, and brake fluid cannot flow between it and the first fluid chamber 2 through the through hole 213a. As a result, the brake fluid sent to the first fluid chamber S1 is not sent from the first fluid chamber S1 to the internal space S3 through the through hole 21231.

[0407] During the application of the brake, the pressure in the first fluid chamber S1 increases, pushing the opening / closing member 22 radially outward from the housing 21 and moving away from the valve body 222a. Therefore, the through hole 201f is opened, and the opening / closing member 222 moves between the first fluid chamber S1 and the master cylinder 13 through the through hole 201f.

[0408]

[0409] This results in a state where braking is possible. Therefore, as shown by the dashed arrow in Figure 7, the brake fluid sent to the fluid chamber S1 passes through hole 2 and is discharged from port P3. After that, the brake fluid discharged from port P3 is sent again to the inside of the damping device 20 via port P4, and then sent to the wheel cylinder through port P2. Thus, braking force is automatically generated on the wheel 17.

[0410]

[0196]

[0411] Here, during the execution of the emergency automatic brake, the opening / closing member 223 is in the closed state. Specifically, during the execution of the emergency automatic brake, the brake fluid sent to the first fluid chamber S1 is not sent from the first fluid chamber S1 to the first internal space S3 of the piston 231 via the through hole 213a, so there is no relative movement of piston 232 with respect to piston 231. Therefore, the pressure in the space to the right of piston 232 within the first internal space S3 does not increase, and the valve body 223a of the opening / closing member 223 is in contact with the edge of the through hole 231a6 due to the biasing force of the biasing member 223b. In other words, brake fluid cannot flow through the through-hole 231a6 between the space to the right of piston 232 in the first internal space S3 and the space to the right of piston 231 in the second fluid chamber S2.

[0412]

[0197]

[0413] (Effect of damping device)

[0414] The effects of the damping device 2〇〇 according to the second embodiment of the present invention will be described.

[0415]

[0198]

[0416] The damping device 200 includes a first liquid chamber S1 that communicates with the discharge side of the pump 36 and the master cylinder 13, a second liquid chamber S2 that communicates with the first liquid chamber S1 and the master cylinder 13, a first opening / closing member (in the above example, opening / closing member 221) that opens and closes the space between the first liquid chamber S1 and the second liquid chamber S2, a first piston (in the above example, piston 231) slidably mounted in the second liquid chamber S2, a first internal space S3 formed inside the first piston and opening to the first liquid chamber S1 side, a second piston (in the above example, piston 232) mounted in the first internal space S3 and slidably mounted relative to the first piston, and The device includes a second opening / closing member (in the above example, opening / closing member 223) that opens and closes the space in the internal space S3 that is opposite to the first liquid chamber S1 relative to the second piston, and the space in the second liquid chamber S2 that is opposite to the first liquid chamber S1 relative to the first piston. Furthermore, when the pump 36 is driven while the brakes are being applied (in the above example, when anti-lock brake control is being performed), the first piston moves toward the first liquid chamber S1, causing the first opening / closing member to open, and the second opening / closing member opens and closes as the second piston slides toward the first piston. When the pump 36 is driven while the brakes are not being applied (in the above example, when the emergency automatic brake is being performed), the L piston moves toward the opposite side of the first liquid chamber S1, causing the first opening / closing member to close, and the second opening / closing member to close.

[0417]

[0199]

[0418] As a result, when the pump 36 is driven while the brakes are being applied, the brake fluid sent to the first fluid chamber S1 as the pump 36 is driven is sent to the first internal space S3, similar to the damping device 100 described above, thereby damping the pressure pulsation caused by the sliding of the second piston against the first piston. Furthermore, when the pump 36 is driven while the brakes are being applied, the second opening / closing member opens and closes in accordance with the sliding of the second piston against the first piston, similar to the damping device 1〇〇 described above, thereby enhancing the effect of damping pressure pulsation by accumulating pressure in the space to the right of the second piston within the first internal space S3, as described above. On the other hand, when the pump 36 is driven while the brakes are not being applied, the brake fluid sent to the first fluid chamber S1 as a result of the pump 36 being driven can be sent to the wheel cylinder without being sent to the first internal space S3, similar to the damping device 100 described above. Therefore, the damping device 200 can appropriately dampen the pressure pulsation of the hydraulic control unit 15, similar to the damping device 100 described above.

[0419] [ 0 2 0 0 ]

[0420] Furthermore, the damping device 200 includes a biasing member 242 that biases the second piston (piston 232 in the above example) toward the first liquid chamber S!. This enhances the effect of damping pressure pulsations caused by the sliding of the second piston relative to the first piston!. However, the biasing member 242 may be omitted from the damping device 200.

[0421] [ 0 2 0 1 ]

[0422] Furthermore, the damping device 200 includes a second internal space S4 formed inside the second piston (piston 232 in the above example) and opening to the first liquid chamber S1, and a cylindrical second elastic member (elastic member 251 in the above example) provided in the second internal space S4 and having at least a hole 251a opening to the first liquid chamber S1. Thus, when the pump 36 is driven under conditions where the brake is being operated, pressure pulsation can be dampened not only by the sliding of the second piston relative to the first piston, but also by the expansion and contraction of the elastic member 251. However, the second elastic member may be omitted from the damping device 200.

[0423] [0 2 0 2] Furthermore, the damping device 200 includes a valve body 223a that opens and closes the space in the first internal space S3 that is opposite to the first liquid chamber S1 relative to the second piston (piston 232 in the above example) and the space in the second liquid chamber S2 that is opposite to the first liquid chamber S1 relative to the first piston (piston 231 in the above example). When the second opening and closing member is in the open state, the valve body 223a comes into contact with the surrounding member (cover 231c in the above example). This allows the open state of the second opening and closing member to be stably maintained. However, when the second opening / closing member is in the open position, the valve body 223a does not need to be in contact with the surrounding members.

[0424] [ 0 2 0 3 ]

[0425] Furthermore, the damping device 200 includes a second opening / closing member (in the above example, opening / closing member 223) which includes a valve body 223a that opens and closes the space in the first internal space S3 that is opposite to the first liquid chamber S1 with respect to the second piston (in the above example, piston 232) and the space in the second liquid chamber S2 that is opposite to the first liquid chamber S! with respect to the first piston (in the above example, piston 231). The valve body 223a is provided so as to be linearly slidable in the direction of opening and closing the space in the first internal space S3 that is opposite to the first liquid chamber S! with respect to the second piston and the space in the second liquid chamber S2 that is opposite to the first liquid chamber S! with respect to the first piston. This prevents the valve body 223a from moving in directions other than the direction of opening and closing the two spaces mentioned above (for example, in the radial direction of the housing 201 in the above example), thus enabling stable opening and closing of the through hole 231a6 by the valve body 223a. However, the valve body 223a does not necessarily have to be provided so as to be able to slide linearly in the direction of opening and closing the two spaces mentioned above.

[0426] [ 0 2 0 4 ]

[0427] Furthermore, the damping device 200 includes a third opening / closing member (in the above example, opening / closing member 222) that opens and closes the space between the first liquid chamber S1 and the master cylinder 13 in response to pressure changes in the first liquid chamber S1. As a result, as shown in Figure 5, in normal operation when anti-lock brake control or emergency automatic braking is not being performed, it is possible to make it impossible for brake fluid to flow between the first liquid chamber S1 and the master cylinder 13 through the through hole 201f. Therefore, it is possible to suppress the supply of brake fluid from the master cylinder 13 to the first liquid chamber S1 via port P3 when the brakes are operated. Thus, in normal operation, it is possible to suppress the unnecessary supply of a portion of the brake fluid supplied from the master cylinder 13 to the first internal space S3. This makes it possible to suppress a decrease in responsiveness when generating braking force on the wheel 17 by braking, for example. However, the third opening / closing member may be omitted from the damping device 100.

[0428]

[0205]

[0429] Although preferred embodiments of the present invention have been described above with reference to the attached drawings, it goes without saying that the present invention is not limited to the embodiments described above, and that various modifications or alterations within the scope of the claims also fall within the technical scope of the present invention.

[0430]

[0206]

[0431] For example, the sliding direction of pistons 1 3 1 and 2 3 1 may differ from the axial direction of the housing. For example, the central axis of the second liquid chamber S 2 may be different from the housing

[0432]

[0433] When not arranged coaxially with 0 1, the sliding direction of pistons 1 3 1 and 2 3 1 is different from the axial direction of housings 1 0 1 and 2 0 1. Furthermore, the sliding direction of pistons 1 3 2, 1 3 3, and 2 3 2 may also be different from the axial direction of housings 1 0 1 and 2 0 1.

[0434] [0 2 0 7]

[0435] Furthermore, for example, the cross-sectional shape of the second liquid chamber S 2 in a cross section orthogonal to the sliding direction of pistons 1 3 1 and 2 3 1 does not need to be circular. The cross-sectional shape may be, for example, elliptical or polygonal. In this case, the cross-sectional shape of each member such as pistons 1 3 1 and 2 3 1 can be appropriately set corresponding to the cross-sectional shape of the second liquid chamber S 2. Furthermore, the cross-sectional shapes of pistons 1 3 2, 1 3 3, 2 3 2, the first internal space S 3, and the second internal space S 4 do not need to be circular either.

[0436] Description of Symbols

[0437] [0 2 0 8]Brake system

[0438] 1 Brake pedal

[0439] 2 Booster device

[0440] 3 Master cylinder

[0441] 4 Reservoir

[0442] 5 Hydraulic pressure control unit

[0443] 6 Brake device

[0444] 7 Wheel

[0445] 1 Main flow path

[0446] 2 Sub flow path

[0447] 3 Supply flow path

[0448] 1 Inlet valve

[0449] 2 Outlet valve

[0450] 3 First valve

[0451] 4 Second valve

[0452] 5. Accumulator

[0453] 6 pumps

[0454] 7 Motor

[0455] 〇 〇 Damping device

[0456] 〇 ! Housing

[0457] 1! Cover

[0458] 1 2 Cover

[0459] 1 3 valve seats

[0460] 2 1 Opening / closing member (first opening / closing member) 2 1 a Valve body

[0461] 2 1 b Biasing member

[0462] 2 2 Opening / closing member (third opening / closing member) 2 2 a Valve body

[0463] 2 2 b Biasing member

[0464] 2 3 Opening / closing member (second opening / closing member) 2 3 a Valve body

[0465] 2 3 b Biasing member

[0466] 3 1 Piston (1st piston) 3 2 Piston (2nd piston) 3 3 Piston (3rd piston) 4 1 Biasing member

[0467] 4 2 Biasing member

[0468] 5! Elastic member (1st elastic member) ○ ○ Damping device

[0469] 〇 ! Housing

[0470] 1! Cover

[0471] 1 2 Cover

[0472] 1 3 valve seats

[0473] 2 1 Opening / closing member (first opening / closing member) 2 1 a Valve body

[0474] 2 1 b Biasing member

[0475] 2 2 Opening / closing member (third opening / closing member) 2 2 a Valve body

[0476] 2 2 b Biasing member

[0477] 2 3 Opening / closing member (second opening / closing member) piston) piston) elastic member)

[0478]

[0479] S 3 First internal space

[0480] S 4 Second internal space

Claims

1. [Document Name ] Claims

1. A damping device (100, 200) is provided in a hydraulic control unit (15) that controls the braking force generated on the wheel (17), and is positioned in the brake fluid flow path between the discharge side of the pump (36) and the master cylinder (13) to dampen pressure pulsations, The first liquid chamber (S1) communicates with the discharge side of the pump (36) and the master cylinder (13), respectively. The first liquid chamber (S1) and the second liquid chamber (S2) communicate with the master cylinder (13), respectively. A first opening / closing member (1 2 1 2 2 1) opens and closes the gap between the first liquid chamber (S 1) and the second liquid chamber (S 2), A first piston (131, 231) is slidably mounted in the second liquid chamber (S2), and a first internal space (S3) is formed inside the first piston (131, 231) and opens to the first liquid chamber (S1). A second piston (132, 232) is provided in the first internal space (S3) and is slidable relative to the first piston (131, 231), A second opening / closing member (123, 223) opens and closes the space in the first internal space (S3) that is opposite to the first liquid chamber (S1) relative to the second piston (132, 232), and the space in the second liquid chamber (S2) that is opposite to the first liquid chamber (S1) relative to the first piston (131, 231), Equipped with, When the pump (36) is driven while the brakes are being applied, the first piston (131, 231) moves toward the first liquid chamber (S1), causing the first opening / closing member (121, 221) to open, and the second opening / closing member (123, 223) opens and closes in accordance with the sliding of the second piston (132, 232) relative to the first piston (131, 231). When the pump (36) is driven while the aforementioned brake operation is not performed, the first piston (131, 231) moves to the opposite side from the first liquid chamber (S1), causing the first opening / closing member (121, 221) to close and the second opening / closing member (123, 223) to close. Damping device.

2. The device includes biasing members (142, 242) that bias the second piston (132, 232) toward the first liquid chamber (S1). The damping device according to claim 1.

3. A second internal space (S4) is formed inside the second piston (132) and opens to the first liquid chamber (S1), A third piston (133) is provided in the second internal space (S4) and is slidable relative to the second piston (132), A first elastic member (151) is provided in the second internal space (S4) on the side opposite to the first liquid chamber (S1) relative to the third piston (133), and elastically deforms as the third piston (133) slides relative to the second piston (132), Equipped with, The damping device according to claim !.

4. The first elastic member (151) includes a plurality of regions (R1, R2, R3) with different hardnesses. The damping device according to claim 3.

5. A second internal space (S4) formed inside the second piston (232) and opening to the liquid chamber (S1) side, A cylindrical second elastic member (251) is provided in the second internal space (S4) and has a hole (251a) that opens at least to the first liquid chamber (S1) side, Equipped with, The damping device according to claim 1.

6. The second opening / closing member (123, 223) includes valve bodies (123a, 223a) that open and close the space in the first internal space (S3) opposite to the first liquid chamber (S1) relative to the second piston (132, 232), and the space in the second liquid chamber (S2) opposite to the first liquid chamber (S1) relative to the L piston (131, 231). When the second opening / closing member (123, 223) is in the open position, the valve body (123a, 223a) comes into contact with the surrounding members (131c, 231c). The damping device according to claim 1.

7. The second opening / closing member (123, 223) includes valve bodies (123a, 223a) that open and close the space in the first internal space (S3) opposite to the first liquid chamber (S1) relative to the second piston (132, 232), and the space in the second liquid chamber (S2) opposite to the first liquid chamber (S1) relative to the first piston (131, 231). The valve body (123a, 223a) is provided so as to be linearly slidable in a direction that opens and closes the space in the first internal space (S3) that is opposite to the first liquid chamber (S1) relative to the second piston (132, 232), and the space in the second liquid chamber (S2) that is opposite to the first liquid chamber (S1) relative to the first piston (131, 231). The damping device according to claim 1.

8. The system includes a third opening / closing member (122, 222) that opens and closes the gap between the first liquid chamber (S1) and the master cylinder (13) in accordance with the pressure change in the first liquid chamber (S1). The damping device according to claim 1.

9. A hydraulic control unit comprising a damping device (100, 200) according to any one of claims 1 to 8. [Claim 1〇] A brake system comprising the hydraulic control unit (15) according to claim 9.

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