Damping device, hydraulic control unit, and brake system

Abstract

The present invention dampens pressure pulsation in a hydraulic control unit. A damping device according to the present invention comprises: a first piston that is provided in a housing; a first liquid chamber that is a space in the housing on one side in the sliding direction relative to the first piston and that communicates with each of the discharge side of a pump and a master cylinder; a second liquid chamber that is a space in the housing on the other side in the sliding direction relative to the first piston and that communicates with the master cylinder; a first internal space that is formed inside the first piston and that opens to the first liquid chamber side; a cylindrical first elastic member that is provided in the first internal space and that has a hole which opens to at least the first liquid chamber side; and a first opening / closing member that opens / closes between the first liquid chamber and the first internal space, wherein, when the pump is driven in a condition in which a brake operation is being performed, the first piston moves to the first liquid chamber side, thereby setting the first opening / closing member to an open state, and when the pump is driven in a condition in which the brake operation is not being performed, the first piston moves to the second liquid chamber side, thereby setting the first opening / closing member to a closed state.

Description

[0001] Damping device, hydraulic pressure control unit and brake system

[0002] [Document Name] Description

[0003] [Title of the Invention] Damping device, hydraulic pressure control unit and brake system

[0004] [Technical Field]

[0005]

[0001]

[0006] The present invention relates to a damping device, a hydraulic pressure control unit, and a brake system.

[0007] [Background Art]

[0008]

[0002]

[0009] 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 path within the hydraulic pressure control unit. In such a hydraulic pressure control unit, for example, in anti-lock brake control or the like, control is performed to set the open / closed states of the respective valves to specific states and drive the pump.

[0010] [Prior Art Document]

[0011] [Patent Document]

[0012]

[0003]

[0013] [Patent Document 1] Japanese Unexamined Patent Application Publication No. 2010-052519

[0014] [Summary of the Invention]

[0015] [Problem to be Solved by the Invention]

[0016]

[0004]

[0017] 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, which is a phenomenon in which the hydraulic pressure of the brake fluid pulsates. The sound produced by such pressure pulsation may be perceived as noise by the vehicle occupants and can be a factor that impairs comfort. In particular, when anti-lock brake control is being performed, the sound produced by pressure pulsation is likely to be a factor that impairs comfort. Therefore, from the perspective of improving comfort, it is desirable to appropriately attenuate the pressure pulsation in the hydraulic control unit.

[0018] [ 0 0 0 5 ]

[0019] 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.

[0020] [Means for solving the problem]

[0021] [ 0 0 0 6 ]

[0022] 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 to dampen pressure pulsations, and comprises a housing, a first piston slidably provided within the housing, a second fluid chamber which is the space within the housing on one side of the sliding direction of the first piston relative to the first piston and communicates with the discharge side of the pump and the master cylinder, respectively, a second fluid chamber which is the space within the housing on the other side of the sliding direction of the first piston and communicates with the master cylinder, a first internal space formed inside the first piston and opening to the first fluid chamber side, a cylindrical first elastic member provided in the first internal space and having at least a hole opening to the first fluid chamber side, and a first opening / closing member which opens and closes the space between the first fluid chamber and the first internal space, and when the pump is driven while the brakes are being operated, the first piston 1. When the first opening / closing member moves toward the liquid chamber, the first opening / closing member opens. When the pump is running without brake operation, the first piston moves toward the second liquid chamber, causing the first opening / closing member to close.

[0023] [ 0 0 0 7 ]

[0024] To solve the above problems, the hydraulic control unit is equipped with the damping device described above.

[0025] [ 0 0 0 8 ]

[0026] To solve the above problems, the brake system is equipped with the above-described hydraulic control unit. [Effects of the invention]

[0027] [ 0 0 0 9 ]

[0028] According to the present invention, it is possible to attenuate the pressure pulsation of the hydraulic control unit.

[0029] [Brief explanation of the drawing]

[0030] [ 0 0 1 0 ]

[0031] [Figure 1] This is a schematic diagram showing the general configuration of a brake system according to an embodiment of the present invention. [Figure 2] This is a cross-sectional view showing the general configuration of a damping device according to an embodiment of the present invention.

[0032] [Figure 3] This figure shows the state of the damping device according to an embodiment of the present invention during the execution of anti-lock brake control.

[0033] [Figure 4] This figure shows the state of the damping device according to an 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] < Brake system configuration >

[0041] Referring to Figure 1, the configuration of a brake system according to an embodiment of the present invention will be described. [0 0 1 4]

[0042] Fig. 1 is a schematic diagram showing a schematic configuration of a brake system 1. The brake system 1 is mounted on a vehicle and is a system for controlling braking force generated in the vehicle. As shown in Fig. 1, the brake system 1 includes a brake pedal 11, a booster device 12, a master cylinder 13, a reservoir 14, a hydraulic pressure control unit 15, a brake device 16, and wheels 17.

[0043] [ 0 0 1 5 ]

[0044] The brake system 1 is mounted on a vehicle having four wheels, and each wheel 17 is braked by the brake device 16 provided on each wheel 17. The braking force generated in each wheel 17 is controlled by the hydraulic pressure control unit 15. In Fig. 1, for ease of understanding, only portions related to two wheels 17 (e.g., a left front wheel and a right rear wheel) among the total four wheels 17 are shown, and illustration of portions related to the other two wheels 17 (e.g., a right front wheel and a left rear wheel) is omitted.

[0045] [ 0 0 1 6 ]

[0046] Note that the number of wheels 17 whose braking force is controlled by the hydraulic pressure control unit 15 may be other than four. For example, the number of wheels 17 whose braking force is controlled by the hydraulic pressure control unit 15 may be two. In that case, the brake system 1 can be mounted on a vehicle having two wheels 17.

[0047] [ 0 0 1 7 ]

[0048] The brake pedal 11 is used in a braking operation by a driver. In the braking operation, the brake pedal 11 is depressed by the driver. The booster 12 is connected to the brake pedal 11, and amplifies the depressing force applied to the brake pedal 11. The master cylinder 13 is connected to the booster 12, incorporates a piston that reciprocates in conjunction with the brake pedal 11, and generates hydraulic pressure corresponding to the operation amount of the braking operation. The reservoir 14 is attached to the master cylinder 13 and stores brake fluid.

[0049] [ 0 0 1 8 ]

[0050] The hydraulic pressure control unit 15 includes a base body 15a in which a brake fluid flow path is formed. The master cylinder 13 and each brake device 16 are respectively connected to the base body 15a of the hydraulic pressure control unit 15. The brake fluid flow path in the base body 15a of the hydraulic pressure control unit 15 is connected to a 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 a wheel 17.

[0051] [ 0 0 1 9 ]

[0052] In the base body 15a of the hydraulic pressure control unit 15, a main flow path 21, a sub flow path 22, and a supply flow path 23 are formed as brake fluid flow paths. The main flow path 21 allows the brake fluid from the master cylinder 13 to flow to the wheel cylinder of the brake device 16. The sub flow path 22 discharges the brake fluid from the wheel cylinder of the brake device 16. The supply flow path 23 supplies the brake fluid from the master cylinder 13 to the sub flow path 22. Note that a part of the flow paths described above includes a flow path inside a damping device 100 described later.

[0053] [ 0 0 2 0 ]

[0054] Furthermore, the base 15a of the hydraulic control unit 15 is equipped with a suction valve (EV) 31, a release valve (AV) 32, a second 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.

[0055] [ 0 0 2 1 ]

[0056] 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.

[0057] [ 0 0 2 2 ]

[0058] The main flow path 21 connects the master cylinder 13 and the wheel cylinder of the brake device 6. 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 path 21b is provided with a suction valve 31.

[0059] [ 0 0 2 3 ]

[0060] 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.

[0061] [ 0 0 2 4 ]

[0062] Pump 36 is driven by motor 37 and draws brake fluid from the first sub-flow channel 22a and discharges it to the main flow channel 21. Pump 36 is a reciprocating plunger pump. Specifically, the plunger of pump 36 reciprocates when it is intermittently pressed by an eccentric cam located on the output shaft of motor 37. This causes pump 36 to pump the brake fluid.

[0063] [ 0 0 2 5 ]

[0064] The supply passage 23 connects the master cylinder 13 side of the main passage 21 via the first valve 33 to the suction side of the pump 36 in the sub-passage 22. A second valve 34 is provided in the supply passage 23.

[0065] [0 0 2 6] The suction valve 31 is, for example, a solenoid valve that is opened 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 opened 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 17 is controlled by controlling the operation of these valves and the motor 37.

[0066] [ 0 0 2 7 ]

[0067] 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 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.

[0068] [ 0 0 2 8 ]

[0069] 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.

[0070] [ 0 0 2 9 ]

[0071] 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.

[0072] [ 0 0 3 0 ]

[0073] Then, when both the fill valve 31 and the release valve 32 are closed from the above state, the flow of brake fluid between the main passage 21 and the sub-passage 22 and the wheel cylinder stops, and the hydraulic pressure of the brake fluid in the wheel cylinder is maintained, thus maintaining the braking force applied to the wheel 17. Subsequently, when the fill valve 31 is opened and the release valve 32 is closed, the flow of brake fluid between the main passage 21 and the wheel cylinder resumes, the hydraulic pressure of the brake fluid in the wheel cylinder increases, and the braking force applied to the wheel 17 increases.

[0074] [ 0 0 3 1 ]

[0075] 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, other types of control may also be implemented.

[0076] [ 0 0 3 2 ]

[0077] 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.

[0078] [ 0 0 3 3 ]

[0079] 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.

[0080] [ 0 0 3 4 ]

[0081] 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.

[0082] [ 0 0 3 5 ]

[0083] 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.

[0084] [ 0 0 3 6 ]

[0085] The damping device 100 includes a main body 200 and an opening / closing member 300 provided on the outside of the main body 200. The main body 200 is positioned in the brake fluid flow path between the discharge side of the pump 36 and the master cylinder 13. In the example in Figure 1, the main body 200 is positioned across the portion of the 11th main flow path 21a between the suction valve 31 and the first valve 33, and the portion of the second subflow path 22b downstream of the pump 36. The main body 200 has ports P1, P2, P3, and P4.

[0086] [ 0 0 3 7 ]

[0087] Within the main body 200, 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 main body 200 that is on the side of the inlet valve 31. Port P4 is connected to the portion of the first main flow path 21a that is on the side of the main body 200 that is on the side of the first valve 33. 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 main body 200 is included in the first main flow path 21a.

[0088] [ 0 0 3 8 ]

[0089] Within the main unit 200, ports P1 and P3 are in communication with each other. Port P1 is connected to the portion of the second sub-channel 22b that is on the pump 36 side relative to the main unit 200. Port P3 is connected to the portion of the second sub-channel 22b that is on the first main channel 21a side relative to the main unit 200. In other words, the second sub-channel 22b passes through ports P1 and P3. To put it another way, the channel connecting ports P1 and P3 within the main unit 200 is included in the second sub-channel 22b.

[0090] [ 0 0 3 9 ]

[0091] The opening / closing member 300 is provided between the port b P3 of the main body 200 and the first main flow path 21a in the second sub-flow path 22b. In other words, the flow path inside the opening / closing member 300 is included in the second sub-flow path 22b.

[0092] [ 0 0 4 0 ]

[0093] <Configuration of the damping device>

[0094] Referring to Figure 2, the details of the configuration of the damping device XX according to an embodiment of the present invention will be described.

[0095] [ 0 0 4 1 ]

[0096] 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 the 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.

[0042]

[0097] As described above, the damping device 100 includes a main body 200 and an opening / closing member 300 provided outside the main body 200. The opening / closing member 300 corresponds to an example of the third opening / closing member according to the present invention.

[0098] [ 0 0 4 3 ]

[0099] As shown in Figure 2, the main body 200 comprises a housing 201, a cover 211, a piston 221, a piston 222, a biasing member 231, a biasing member 232, an opening / closing member 241, an opening / closing member 242, an elastic member 251, a holding member 261, and an elastic member 271. Note that the pistons 221, 222, 241, 242, elastic member 251, and elastic member 271 correspond to examples of the first piston, second piston, first opening / closing member, second opening / closing member, first elastic member, and second elastic member according to the present invention.

[0100] [ 0 0 4 4 ]

[0101] The housing 201 is formed in a cylindrical shape with a hollow space inside. In Figure 2, the main body 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 3 and 4, which will be described later, coincides with the left-right direction in Figure 2.

[0102] [ 0 0 4 5 ]

[0103] The hollow space inside housing 201 opens on the left side of housing 201 and is closed on the right side. The inner circumferential surface 201a of housing 201 is formed in a substantially cylindrical shape.

[0104] [ 0 0 4 6 ]

[0105] Of the hollow space inside housing 2 0 1, the space to the left of piston 2 2 1 (described later) corresponds to the first liquid chamber S 1. Of the hollow space inside housing 2 0 1, the space to the right of piston 2 2 1 (described later) corresponds to the second liquid chamber S 2.

[0106] [ 0 0 4 7 ]

[0107] The aforementioned ports P1, P2, P3, and P4 are formed on the outer circumferential surface of the housing 201.

[0108] [ 0 0 4 8 ]

[0109] 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 20l and opens to the inner circumferential surface 20a.

[0110] [ 0 0 4 9 ]

[0111] 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.

[0112] [ 0 0 5 0 ]

[0113] Port P3 communicates with the first liquid chamber S1 through a through-hole 2Old formed in the housing 201. The through-hole 2Old extends radially in the housing 201 and opens to the inner circumferential surface 2Oa.

[0114] [ 0 0 5 1 ]

[0115] Port P4 communicates with the second liquid chamber S2 through a through-hole 201e formed in the housing 201. The through-hole 20le extends radially in the housing 201 and opens to the inner circumferential surface 20a.

[0116] [ 0 0 5 2 ]

[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 master cylinder 13 via port P4.

[0118] [ 0 0 5 3 ]

[0119] Cover 211 is attached to the left side of housing 201 and covers the internal space of housing 201 from the left side. Cover 211 has a substantially cylindrical shape that extends in the axial direction of housing 201. Cover 211 is positioned, for example, coaxially with housing 201. Cover 211 is fitted onto the inner circumferential surface 201a. Cover 211 is fixed to housing 201. Cover 211 is provided with a projection 2I la, a hole 2 lib, a base 211 c, and a projection 2 lid.

[0120] [ 0 0 5 4 ]

[0121] The projection 211a protrudes to the right from the right side of the cover 211. The projection 211a has a substantially cylindrical shape and is coaxial with the housing 2〇1. The outer circumferential surface of the projection 211a is fitted into the inner circumferential surface 2Ola of the housing 2〇1.

[0122] [ 0 0 5 5 ]

[0123] Hole 211b is recessed from the right side of projection 211a to the left side. Hole 211b opens on the right side of projection 211a and closes on the left side. Hole 211b has a substantially cylindrical shape and is coaxial with housing 2〇1.

[0124] [ 0 0 5 6 ]

[0125] Base 211c protrudes to the right from the bottom surface of hole 211b (i.e., the surface facing the right). Base 211c has a substantially cylindrical shape and is coaxial with housing 201. The outer diameter of base 211c is smaller than the inner diameter of hole 211b. In other words, the outer surface of base 211c is separated from the inner surface of hole 211b. The right surface of base 211c is located to the left of the right surface of projection 211a.

[0126] [ 0 0 5 7 ]

[0127] Projection 2 lid protrudes to the right from the right surface of base 211c. Projection 211d has a substantially cylindrical shape and is coaxial with housing 201. The outer diameter of projection 211d is smaller than the outer diameter of base 211c. The tip (i.e., the right end) of projection 211d is located to the right of the right surface of projection 211a.

[0128] [ 0 0 5 8 ]

[0129] The piston 221 is located in the internal space of the housing 201, which is partitioned by the inner surface of the housing 201 and the right side of the cover 211. The piston 221 has a substantially cylindrical shape that extends axially from the housing 201. The piston 221 is, for example, positioned coaxially with the housing 201. The piston 221 is slidably mounted axially within the housing 201. The piston 221 includes a body 221a, a cover 221b, a valve seat 221c, and a cover 221d.

[0130] [ 0 0 5 9 ]

[0131] The main body 221a forms the general shape of the piston 221. The main body 221a has a substantially cylindrical shape that extends axially from the housing 201. The main body 221a is, for example, positioned coaxially with the housing 201. The outer circumferential surface of the main body 221a is slidable relative to the inner circumferential surface 201a. The main body 221a is provided with a seal 221al, a hole 221a2, a groove 221a3, a hole 221a4, a groove 221a5, and a through hole 221a6.

[0132] [ 0 0 6 0 ]

[0133] The seal 221a1 is, for example, an O-ring. The seal 221a1 is formed in an annular shape extending circumferentially from the main body 221a and is fitted onto the outer circumferential surface of the main body 221a. The seal 221a1 is pressed against the inner circumferential surface 2Ola. This seals the gap between the outer circumferential surface of the main body 221a and the inner circumferential surface 2Ola in a liquid-tight manner. In the example in Figure 2, there are two seals 221a1. However, the number of seals 221a1 may be one, three or more.

[0134] [ 0 0 6 1 ]

[0135] Hole 221a2 is located coaxially with the main body 221a, opening to the left side of the main body 221a and closing to the right side. Hole 221a2 has a substantially cylindrical shape that extends axially along the main body 221a. As will be described later, hole 221a2 opens to the first fluid chamber S1 side through the through hole 221cl of the valve seat 221c and the through hole 221b3 of the cover 221b. In other words, hole 221a2 is formed inside the piston 221 and corresponds to the first internal space S3 that opens to the first fluid chamber S1 side.

[0136] [0 0 6 2] Groove 221a3 is formed to the left of hole 221a2 in an annular shape coaxial with hole 221a2, and is a portion in which the inner diameter is enlarged. Cover 221b is fitted into this groove 221a3.

[0137] [ 0 0 6 3 ]

[0138] Cover 221b is fixed to groove 221a3 of main body 221a. Cover 221b is formed in a substantially cylindrical shape coaxial with housing 2〇1. The outer surface of cover 221b is sintered to the inner surface of groove 221a3. Cover 221b is provided with hole 221bl, groove 221b2, and through hole 221b3.

[0139] [ 0 0 6 4 ]

[0140] Hole 221b is located coaxially with cover 221b, opening on the left side of cover 221b and closing on the right side. Hole 221b has a roughly cylindrical shape that extends in the axial direction of cover 221b. Groove 221b2 is formed to the left of hole 221b1 in an annular shape coaxial with hole 221b1, and is a portion where the inner diameter expands. Through hole 221b3 is formed on the bottom surface of hole 221b1 (the surface facing left) and connects cover 221b in the left-right direction.

[0141] 0 0 6 5 ]

[0142] The valve seat 221c is provided in the groove 221b2 of the cover 221b. The valve seat 221c is formed in an annular shape coaxial with the housing 2〇1. The valve seat 221c is provided with a through hole 221c1 that penetrates the valve seat 221c in the left-right direction. The outer circumferential surface of the valve seat 221c is fitted into the inner circumferential surface of the groove 221b2. The valve seat 221c is fixed to the cover 221b.

[0143] [ 0 0 6 6 ]

[0144] The opening / closing member 241 is provided in the hole 221b1 of the cover 221b. The opening / closing member 241 includes a valve body 241a and a biasing member 241b. The valve body 241a is, for example, spherical in shape. The biasing member 241b is, for example, a spring. The biasing member 241b is positioned between the bottom surface of the hole 221bl (i.e., the left-facing surface) and the valve body 241a. The biasing member 241b 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 241a is biased to the left by the biasing member 241b.

[0145] [ 0 0 6 7 ]

[0146] The valve body 241a of the opening / closing member 241 is positioned to the right of the through hole 221c1 of the valve seat 221c. The diameter of the valve body 241a is larger than the diameter of the through hole 221c1. The valve body 241a can contact the edge of the through hole 221c1.

[0147] Benma [I 0 0 6 8]

[0148] In the example shown in Figure 2, the valve body 241a is separated from the edge of the through hole 221c1. In this case, the through hole 221c1 is opened by the valve body 241a, and the space between the first fluid chamber S1 and the first internal space S3 is opened (that is, brake fluid can flow between the first fluid chamber S1 and the first internal space S3).

[0149] [ 0 0 6 9 ]

[0150] On the other hand, when the valve body 241a comes into contact with the edge of the through hole 221c1, the through hole 221c1 is closed by the valve body 241a, and the space between the first fluid chamber S1 and the first internal space S3 is closed (that is, brake fluid cannot flow between the first fluid chamber S1 and the first internal space S3). In this way, the valve body 241a opens and closes the through hole 221cl of the valve seat 221c, thereby opening and closing the space between the first fluid chamber S1 and the first internal space S3.

[0151] [ 0 0 7 0 ]

[0152] The hole 221a4 of the main body 221a is positioned coaxially with the main body 221a, opens to the right side of the main body 221a, and closes to the left side. The hole 221a4 has a substantially cylindrical shape that extends in the axial direction of the main body 221a.

[0153] [ 0 0 7 1 ]

[0154] Groove 221a5 is formed to the right of hole 221a4, coaxially with hole 221a4, and is an annular shape in which the inner diameter expands. Cover 221d is fitted into this groove 221a5.

[0155] [ 0 0 7 2 ]

[0156] The cover 221d is fixed to the groove 221a5 of the main body 221a. The cover 221d is formed in a substantially annular shape coaxial with the housing 201. The outer circumferential surface of the cover 221d is fitted to the inner circumferential surface of the groove 221a5.

[0157] [ 0 0 7 3 ]

[0158] The through hole 221a6 is located on the left side of hole 221a4. The through hole 221a6 connects hole 221a4 to the first internal space S3 of piston 221.

[0159] [ 0 0 7 4 ]

[0160] The biasing member 231 is, for example, a spring. The biasing member 231 is positioned between the bottom surface of the hole 211b of the cover 211 (i.e., the side facing to the right) and the cover 221b of the piston 221. The biasing member 231 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 221 is biased to the right by the biasing member 231.

[0161] [ 0 0 7 5 ]

[0162] Piston 222 is provided in the first internal space S3 of piston 221. Piston 222 has a substantially cylindrical shape that extends axially from the housing 201. Piston 222 is, for example, positioned coaxially with the housing 201. Piston 222 is provided so as to be axially slidable in the first internal space S3. That is, piston 222 is provided so as to be slidable relative to piston 221. Piston 222 includes a body 222a and a cover 222b.

[0163] [ 0 0 7 6 ]

[0164] The main body 222a forms the general shape of the piston 222. The main body 222a has a substantially cylindrical shape that extends axially from the housing 201. The main body 222a is, for example, positioned coaxially with the housing 201. The outer circumferential surface of the main body 222a is slidable against the inner circumferential surface of the hole 221a2 of the piston 221. The main body 222a is provided with a seal 222al and the hole 222a2.

[0165] [ 0 0 7 7 ]

[0166] The seal 222a1 is, for example, an O-ring. The seal 222a1 is formed in an annular shape extending circumferentially from the body 222a and is fitted onto the outer circumferential surface of the body 222a. The seal 222a1 is pressed against the inner circumferential surface of the hole 221a2 of the piston 221. This seals the gap between the outer circumferential surface of the piston 222 and the inner circumferential surface of the hole 221a2 of the piston 221 in a liquid-tight seal. In the example in Figure 2, there are two seals 222a1. However, there may be one seal 222a1 or three or more seals 222a1.

[0167] [ 0 0 7 8 ]

[0168] Hole 222a2 is positioned coaxially with the main body 222a, opening to the left side of the main body 222a and closing to the right side. Hole 222a2 has a substantially cylindrical shape and extends axially along the main body 222a. As will be described later, hole 222a2 opens to the first liquid chamber S1 side through a through hole in the cover 222b. In other words, hole 222a2 corresponds to the second internal space S4 formed inside the piston 222 and opening to the first liquid chamber S1 side.

[0169] [ 0 0 7 9 ]

[0170] Cover 222b is fixed to the left side of the inner circumferential surface of hole 222a2 in the main body 222a. Cover 222b is formed in a substantially annular shape coaxial with housing 201. The outer circumferential surface of cover 222b is fitted to the inner circumferential surface of hole 222a2. The second internal space S4 of piston 222 communicates with the first liquid chamber S1 through a through hole provided in the center of cover 222b.

[0171] [ 0 0 8 0 ]

[0172] The biasing member 232 is, for example, a spring. The biasing member 232 is provided in the first internal space S3 of the piston 221. The biasing member 232 is positioned between the bottom surface of the hole 221a2 (i.e., the side facing left) and the piston 222. The biasing member 232 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 piston 222 is biased to the left by the biasing member 232.

[0173] [ 0 0 8 1 ]

[0174] The elastic member 251 is provided in the first internal space S3 of the piston 221. In the example of Figure 2, the elastic member 251 is provided in the second internal space S4 of the piston 222 within the first internal space S3. The elastic member 251 has a cylindrical shape (in the example of Figure 2, a cylindrical shape with a bottom) that extends axially from the housing 201. The elastic member 251 is positioned, for example, coaxially with the housing 201. For example, the outer circumferential surface of the elastic member 251 is fitted into the inner circumferential surface of the hole 222a2 of the piston 222. Furthermore, the elastic member 251 is sandwiched in the left-right direction between the bottom surface of the hole 222a2 of the piston 222 (i.e., the side facing left) and the cover 222b. For example, the entire right surface of the elastic member 251 is in contact with the bottom surface of the hole 222a2 of the piston 222 (i.e., the side facing left), and the entire left surface of the elastic member 251 is in contact with the cover 222b.

[0175] [ 0 0 8 2 ]

[0176] 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 opens on the left side of the elastic member 251 and is closed on the right side. However, the hole 251a only needs to open on the left side. For example, the hole 251a may be a through hole that penetrates the elastic member 251 from left to right. Also, the elastic member 251 may be cylindrical, but does not have to be cylindrical.

[0177] [ 0 0 8 3 ]

[0178] The retaining member 261 is provided in the space to the right of the piston 222 in the first internal space S3. The retaining member 261 is a member for holding the elastic member 27I, which will be described later. The retaining member 261 is fixed to the right side of the piston 222. The retaining member 261 has a cylindrical shape that extends in the axial direction of the housing 2〇1. The retaining member 261 is arranged coaxially with the housing 201, for example. A projection 261a is provided on the right side of the retaining member 261, projecting to the right. The projection 261a has a cylindrical shape that extends in the axial direction of the housing 2〇1. The projection 261a is arranged coaxially with the housing 201, for example.

[0179] [ 0 0 8 4 ]

[0180] The elastic member 271 is provided in the space to the right of the piston 222 within the first internal space S3. The elastic member 271 is formed of a material with a high elastic limit, such as rubber. For example, the elastic member 271 is harder than the elastic member 251. However, the elastic member 271 may be as hard as the elastic member 251, or softer than the elastic member 251. The elastic member 271 has a substantially cylindrical shape that extends in the axial direction of the housing 201. The elastic member 271 is arranged coaxially with the housing 201, for example. Furthermore, from the viewpoint of ensuring the strength of the elastic member 271, it is preferable that the central side of the elastic member 271 in the left-right direction is thicker than the other parts of the elastic member 271 (i.e., the radial length of the elastic member 271 is longer in that side).

[0181] [ 0 0 8 5 ]

[0182] The elastic member 271 is attached to the retaining member 261, sandwiched in the left-right direction between the bottom surface of the hole 221a2 of the piston 221 (i.e., the side facing left) and the retaining member 261. In the example in Figure 2, the elastic member 271 is fitted to the outer circumferential surface of the projection 261a of the retaining member 26I and fixed to the retaining member 261. However, the elastic member 271 may be fixed to the bottom surface of the hole 221a2 of the piston 221, or it may be fixed to both the bottom surface of the hole 221a2 of the piston 221 and the retaining member 261.

[0183] [ 0 0 8 6 ]

[0184] The opening / closing member 242 is provided in the hole 221a4 of the body 221a of the piston 221. The opening / closing member 242 includes a valve body 242a and a biasing member 242b. The valve body 242a has, for example, a spherical shape. The biasing member 242b is, for example, a spring. The biasing member 242b is positioned between the cover 221d and the valve body 242a. The biasing member 242b 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 242a is biased to the left by the biasing member 242b.

[0185] [ 0 0 8 7 ]

[0186] The valve body 242a is positioned to the right of the through-hole 221a6 of the piston 221. The diameter of the valve body 242a is greater than the diameter of the through-hole 221a6. The valve body 242a can contact the edge of the through-hole 221a6.

[0088]

[0187] In the example shown in Figure 2, the valve body 242a is in contact with the edge of the through hole 221a6. In this case, the through hole 221a6 is closed by the valve body 242a, and the space to the right of the piston > 22 in the first internal space S3 and the second fluid chamber S2 are closed off (that is, brake fluid cannot flow between the space to the right of the piston 222 in the first internal space S3 and the second fluid chamber S2).

[0188] [ 0 0 8 9 ]

[0189] On the other hand, when the valve body 242a is separated from the edge of the through hole 221a6, the through hole 221a6 is opened by the valve body 242a, and the space to the right of the piston 222 in the first internal space S3 and the second fluid chamber S2 are opened (that is, brake fluid can flow between the space to the right of the piston 222 in the first internal space S3 and the second fluid chamber S2). In this way, by opening and closing the through hole 221a6 with the valve body 242a, the opening and closing member 242 opens and closes the space to the right of the piston 222 in the first internal space S3 and the second fluid chamber S2.

[0190] [ 0 0 9 0 ]

[0191] As shown in Figure 2, the opening / closing member 300 comprises a housing 301, a cover 311, a piston 321, and a biasing member 331.

[0192] [ 0 0 9 1 ]

[0193] The housing 301 is formed in a cylindrical shape with a hollow space inside. In Figure 2, the opening and closing member 300 is shown so that the axial direction of the housing 301 is left to right. The housing 301 is provided with a hole 301a and a through hole 301b. Hole 301a opens on the right side of the housing 301 and is closed on the left side. The through hole 301b is provided on the bottom surface of hole 301a (i.e., the side facing to the right) and penetrates the housing 301 in the left to right direction. The internal space of the housing 301 communicates with port P3 through the through hole 301b.

[0194] [ 0 0 9 2 ]

[0195] Cover 311 is fixed to the right side of the inner circumferential surface of hole 301a in housing 301. Cover 311 is formed in a substantially annular shape coaxial with housing 301. The outer circumferential surface of cover 311 is fitted to the inner circumferential surface of hole 301a. Cover 311 is provided with a through hole, and the internal space of housing 301 communicates with the first main flow channel 21a through this through hole.

[0196] [ 0 0 9 3 ]

[0197] The piston 321 is provided in the internal space of the housing 30l. The piston 321 has a substantially cylindrical shape that extends axially from the housing 30l. The piston 321 is positioned, for example, coaxially with the housing 30l. The piston 321 is slidably mounted against the inner circumferential surface of the hole 301a in the housing 30l. A projection 321a is provided on the left side of the piston 32l. The projection 321a has, for example, a hemispherical shape.

[0198] [ 0 0 9 4 ]

[0199] The biasing member 331 is, for example, a spring. The biasing member 331 is provided in the internal space of the housing 301. The biasing member 331 is positioned between the cover 311 and the piston 321. The biasing member 331 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 321 is biased to the left by the biasing member 331.

[0200] [ 0 0 9 5 ]

[0201] The projection 321a of the piston 321 is positioned to the right of the through hole 301b. The diameter of projection 321a is greater than the diameter of the through hole 301b. Projection 321a can contact the edge of the through hole 301b.

[0202] [ 0 0 9 6 ]

[0203] In the example shown in Figure 2, projection 321a is in contact with the edge of through-hole 301b. In this case, through-hole 301b is closed by projection 321a, and the space between port P3 and the internal space of housing 301 is closed (i.e., brake fluid cannot flow between the first fluid chamber S1 and the master cylinder 13).

[0097]

[0204] On the other hand, when projection 321a is separated from the edge of through hole 301b, through hole 301b is opened by projection 321a, and the space between port P3 and the internal space of housing 301 is opened (that is, brake fluid can flow between the first fluid chamber S1 and the master cylinder 13). In this way, projection 321a opens and closes through hole 301b, and the opening / closing member 300 opens and closes the space between the first fluid chamber S1 and the master cylinder 13.

[0205] [ 0 0 9 8 ]

[0206] <Operation of the damping device>

[0207] The operation of the damping device 100 according to an embodiment of the present invention will be described with reference to Figures 2 to 4.

[0208] [ 0 0 9 9 ]

[0209] 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, when brake operation is performed, brake fluid is sent from the master cylinder 13 to the inside of the main body 200 via port P4. As a result, the pressure in the second fluid chamber S2 increases, causing the piston 221 to move to the left. Therefore, the projection 211d of the cover 211 pushes the valve body 241a of the opening / closing member 241 to the right, opening the through hole 221c!. In other words, the opening / closing member 241 becomes open, and brake fluid can flow between the first fluid chamber S1 and the first internal space S3 through the through hole 221c1.

[0210] [ 0 1 0 0 ]

[0211] Furthermore, in the example shown in Figure 2, the projection 321a of the opening / closing member 300 comes into contact with the edge of the through-hole 301b due to the biasing force from the biasing member 331. In other words, the opening / closing member 300 closes, making it impossible for brake fluid to flow between the first fluid chamber S1 and the master cylinder 13 through the through-hole 301b.

[0212] [ 0 1 0 1 ]

[0213] 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 main body 200 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.

[0214] [ 0 1 0 2 ]

[0215] Figure 3 shows the state of the damping device 100 during anti-lock brake control. As described above, during anti-lock brake control, the pump 36 is driven while the brakes are being applied.

[0216] [ 0 1 0 3 ]

[0217] During anti-lock brake control, braking is performed, and as in normal operation, the pressure in the second fluid chamber S2 increases, causing the piston 221 to move to the left. Therefore, the projection 211d of the cover 211 pushes the valve body 241a of the opening / closing member 241 to the right, opening the through hole 221c1. In other words, the opening / closing member 241 becomes open, allowing brake fluid to flow between the first fluid chamber S1 and the first internal space S3 through the through hole 221c1.

[0218] [ 0 1 0 4 ]

[0219] 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 main body 2 XX via port P 1. Here, as described above, during anti-lock brake control, the opening / closing member 2 4 1 is in the open state, and brake fluid can flow between the first fluid chamber S 1 and the first internal space S 3 through the through hole 2 2 1 c 1. 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 2 2 1 via the through hole 2 2 1 c 1. Therefore, the pressure in the space to the left of piston 222 in the first internal space S3 increases, pushing piston 222 to the right and moving to the right relative to piston 221. As a result, pressure is accumulated in the space to the right of piston 222 in the first internal space S3, which dampens the pressure pulsation. Furthermore, the force acting on piston 222 is absorbed by the biasing member 232. Thus, the pressure pulsation is also dampened by the expansion and contraction of the biasing member 232 in conjunction with the sliding of piston 222 relative to piston 221.

[0220] [ 0 1 0 5 ]

[0221] Furthermore, as piston 222 moves to the right relative to piston 221, elastic member 271 undergoes elastic deformation as it is pressed to the right by retaining member 261, as shown by the solid arrow in Figure 3. In this way, elastic member 271 undergoes elastic deformation in accordance with the sliding of piston 222 relative to piston 221. Therefore, the pressure pulsation is also dampened by the expansion and contraction of elastic member 271 in accordance with the sliding of piston 222 relative to piston 221.

[0222] [ 0 1 0 6 ]

[0223] 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 222. 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 222 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 the inner surface of the elastic member 251 to stretch outward and the volume of the hole 251a to expand, as shown by the solid arrow in Figure 3. 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.

[0224] [ 0 1 0 7 ]

[0225] During anti-lock brake control, the opening / closing member 300 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 projection 321a of the piston 321 of the opening / closing member 300 will come into contact with the edge of the through hole 301b due to the biasing force of the biasing member 331. In other words, the opening / closing member 300 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 301b.

[0226] [ 0 1 0 8 ]

[0227] On the other hand, during anti-lock brake control, if the pressure in the first fluid chamber S1 rises to a certain level, the piston 321 of the opening / closing member 300 moves to the right, overcoming the biasing force of the biasing member 331, and the projection 321a separates from the through hole 301b. Therefore, the through hole 301b is opened, the opening / closing member 300 becomes open, and brake fluid can flow between the first fluid chamber S1 and the master cylinder 13 through the through hole 301b. 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.

[0228] [ 0 1 0 9 ]

[0229] Here, during the execution of anti-lock brake control, the opening / closing member 242 opens and closes in accordance with the sliding of piston 222 relative to piston 221. For example, during the execution of anti-lock brake control, if piston 222 has not moved significantly to the right relative to piston 221, and the pressure in the space to the right of piston 222 within the first internal space S3 is not very high, then the valve body 242a of the opening / closing member 242 will be in contact with the edge of the through hole 221a6 due to the biasing force of the biasing member 242b. In other words, brake fluid cannot flow through the through hole 221a6 between the space to the right of piston 222 within the first internal space S3 and the second fluid chamber S2.

[0230] [ 〇 1 1 〇 ]

[0231] On the other hand, during anti-lock brake control, if piston 222 moves to a certain extent to the right relative to piston 221, and the pressure in the space to the right of piston 222 within the first internal space S3 increases to a certain extent, the valve body 242a of the opening / closing member 242 moves to the right, overcoming the biasing force of the biasing member 242b, and the valve body 242a separates from the through hole 221a6. Therefore, the through hole 221a6 is opened, the opening / closing member 242 is in the open state, and brake fluid can flow between the space to the right of piston 222 within the first internal space S3 and the second fluid chamber S2 through the through hole 221a6. Therefore, as shown by the dashed arrow in Figure 3, brake fluid is discharged from the space to the right of the piston 222 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 222 in the first internal space S3, and this accumulation of pressure enhances the effect of attenuating pressure pulsations.

[0232] [ 0 1 1 1 ]

[0233] 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.

[0234] [ 0 1 1 2 ]

[0235] During emergency automatic braking, no brake operation is performed, so brake fluid is not supplied from the master cylinder 13 to the main body 200 via port P4. As a result, the biasing force of the biasing member 231 overcomes the pressure in the second fluid chamber S2, and the piston 221 is pushed to the right by the biasing member 231 and moves to the right. Therefore, the projection 211d of the cover 211 separates from the valve body 241a of the opening / closing member 241, and the valve body 241a is pushed to the left by the biasing member 241b and moves to the left. As a result, the valve body 241a contacts the edge of the through hole 221c1, and the through hole 221c1 is closed by the valve body 241a. In other words, the opening / closing member 241 is in the closed state, making it impossible for brake fluid to flow between the first fluid chamber S1 and the first internal space S3 through the through hole 221c1.

[0236] [ 0 1 1 3 ]

[0237] 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 main body 2 0 0 via port P 1. Here, as described above, during the execution of the emergency automatic brake, the opening / closing member 2 4 1 is in a closed state, and brake fluid cannot flow between the first fluid chamber S 1 and the first internal space S 3 through the through hole 2 2 1 c 1. Therefore, the brake fluid sent to the first fluid chamber S 1 is not sent from the first fluid chamber S 1 to the first internal space S 3 of the piston 2 2 1 via the through hole 2 2 1 c 1.

[0238] [〇 ! 1 4]

[0239] Therefore, during the execution of the emergency automatic brake, the pressure in the first fluid chamber S1 increases, pushing the piston 321 of the opening / closing member 30〇 to the right and moving it, causing the projection 321a of the piston 321 to separate from the through hole 301b. Thus, the through hole 301b is opened, the opening / closing member 300 is in the open state, and brake fluid can flow between the first fluid chamber S1 and the master cylinder 13 through the through hole 3〇⁻b. Therefore, as shown by the dashed arrow in Figure 4, the brake fluid sent to the first fluid chamber S1 is discharged into the first main flow path 21a through port P3 and the through hole 301b. Subsequently, the brake fluid discharged into the first main channel 21a is sent back into the main body 200 via port P4, and then sent to the wheel cylinder through port P2. Thus, braking force is automatically generated on the wheel 17.

[0240] [ 0 1 1 5 ]

[0241] Here, during the execution of the emergency automatic brake, the opening / closing member 242 is in a 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 221 via the through hole 221c1, so there is no relative movement of the piston 222 relative to the piston 221. Therefore, the pressure in the space to the right of the piston 222 in the first internal space S3 does not increase, and the valve body 242a of the opening / closing member 242 is in contact with the edge of the through hole 221a6 due to the biasing force of the biasing member 242b. In other words, brake fluid cannot flow through the through-hole 221a6 between the space to the right of the piston 222 in the first internal space S3 and the second fluid chamber S2. <Effect of the braking device>

[0242] The effects of the damping device 1〇〇 according to an embodiment of the present invention will be described.

[0243] [ 0 1 1 7 ]

[0244] The damping device 100 comprises a housing 201, a first piston (piston 221 in the above example) slidably mounted within the housing 201, a first liquid chamber S1 which is the space within the housing 201 on one side (left side in the above example) in the sliding direction of the piston and communicates with the discharge side of the pump 36 and the master cylinder 13, respectively, a second liquid chamber S2 which is the space within the housing 201 on the other side (right side in the above example) in the sliding direction of the first piston and communicates with the master cylinder L3, a first internal space S3 formed inside the first piston and opening to the first liquid chamber S1, and provided in the first internal space S3, at least The device comprises a cylindrical first elastic member (elastic member 251 in the above example) having a hole 251a opening to the liquid chamber S1 side, and a first opening / closing member (opening / closing member 241 in the above example) that opens and closes the space between the first liquid chamber S1 and the first internal space S3. When the pump 36 is driven while the brake operation is being performed (in the above example, when anti-lock brake control is being executed), the first piston moves to the first liquid chamber S1 side, causing the first opening / closing member to open. When the pump 36 is driven while the brake operation is not being performed (in the above example, when emergency automatic braking is being executed), the first piston moves to the second liquid chamber S2 side, causing the first opening / closing member to close.

[0245] [〇 1 1 8 ]

[0246] 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 a result of the pump 36 being driven is sent to the first internal space S3, thereby attenuating the pressure pulsation caused by the expansion and contraction of the first elastic member. 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 attenuate pressure pulsation.

[0247]

[0119]

[0248] On the other hand, when the pump 36 is operating but no brake operation is being performed, the brake fluid sent to the first fluid chamber S1 as a result of the pump 36 operating 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] [ 0 1 2 0 ]

[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 2 1 ]

[0252] In this specification, the side of the object to the first liquid chamber S1 may mean the side 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 piston 221 to the first liquid chamber S1 corresponds to the left side. Also, the side of the object to the second liquid chamber S2 may mean the side from the object toward the second liquid chamber S2, or the side on which the second liquid chamber S2 exists relative to the object. For example, in the above example, the side of the piston 221 to the second liquid chamber S2 corresponds to the right side.

[0253] [ 0 1 2 2 ]

[0254] Furthermore, the damping device 100 includes a second piston (piston 222 in the above example) provided in the first internal space S3 and slidable relative to the first piston (piston 221 in the above example), and a second internal space S4 formed inside the second piston and opening to the first liquid chamber S1 side, with the first elastic member (elastic member 251 in the above example) provided in the second internal space S4. Thus, when the pump 36 is driven under conditions where the brake is being operated, pressure pulsation can be dampened not only by the expansion and contraction of the first elastic member, but also by the sliding of the second piston relative to the first:L piston. However, the second piston may be omitted from the damping device 100. In that case, for example, the elastic member 251 may be directly fitted to the inner circumferential surface of the hole 221a2 of the piston 221.

[0255] [ 0 1 2 3 ]

[0256] Furthermore, the damping device 100 includes a biasing member 232 that biases the second piston (piston 222 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 232 may be omitted from the damping device 100.

[0257] [ 0 1 2 4 ]

[0258] Furthermore, the damping device 100 is provided in the space of the first internal space S3 on the second liquid chamber S2 side relative to the second piston (piston 222 in the above example), and includes a second elastic member (elastic member 271 in the above example) that elastically deforms in accordance with the sliding of the second piston relative to the first piston (piston 221 in the above example). As a result, when the pump 36 is driven while the brake operation is being performed, pressure pulsation can be dampened not only by the expansion and contraction of the first elastic member, but also by the expansion and contraction of the second elastic member. However, the above second elastic member may be omitted from the damping device 100.

[0259] [ 0 1 2 5 ]

[0260] Furthermore, the damping device 100 includes a second opening / closing member (in the example above, opening / closing member 242) that opens and closes the space on the second liquid chamber S2 side of the first internal space S3 relative to the second piston (in the example above, piston 222) and the second liquid chamber S2. When the pump 36 is driven while the brake operation is being performed (in the example above, when anti-lock brake control is being executed), the second opening / closing member opens and closes in accordance with the sliding of the second piston relative to the first piston (in the example above, piston 221). When the pump 36 is driven while the brake operation is not being performed (in the example above, when emergency automatic braking is being executed), the second opening / closing member is in a closed state. As a result, 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. However, the above-mentioned second opening / closing member may be omitted from the damping device 100.

[0261] [ 0 1 2 6 ]

[0262] Furthermore, the damping device 1〇〇 includes a third opening / closing member (in the above example, opening / closing member 300) that opens and closes the space between the first fluid chamber S! and the master cylinder 13 in response to pressure changes in the first fluid chamber S!. 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 S! and the master cylinder 13 through the through hole 301b. Therefore, it is possible to suppress the supply of brake fluid from the master cylinder 13 to the first fluid chamber S! via port P3 when the brakes are applied. 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 internal space S!. This makes it possible to suppress a decrease in responsiveness when generating braking force on the wheel 17 through brake operation, for example. However, the above-mentioned third opening / closing member may be omitted from the damping device 100. [0 1 2 7]

[0263] 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.

[0264] [ 0 1 2 8 ]

[0265] For example, the sliding direction of piston 221 may differ from the axial direction of housing 2〇1. For instance, if the central axis of the internal space of housing 201 is not coaxial with housing 201, the sliding direction of piston 221 will be different from the axial direction of housing 2〇1. The sliding direction of piston 222 may also differ from the axial direction of housing 201. [0 1 2 9]

[0266] Furthermore, for example, the cross-sectional shape of the internal space of the housing 201 in a cross-section perpendicular to the sliding direction of the piston 221 does not have to be circular. This cross-sectional shape may be, for example, elliptical or polygonal. In that case, the cross-sectional shapes of each component, such as the piston 22i, can be appropriately set in correspondence with the cross-sectional shape of the internal space of the housing 201. Note that the cross-sectional shapes of the piston 222, the first internal space S3, and the second internal space S4 may also be other than circular.

[0267] stem

[0268] pedal

[0269] Cylinder

[0270] unit

[0271] Device

[0272] Let's

[0273] Place

[0274] ng

[0275] (First piston)

[0276] (Second piston)

[0277] Material

[0278]

[0279] Material

[0280] 2 4 1 Opening / closing member (First opening / closing member)

[0281] 2 4 2 Opening / closing member (second opening / closing member)

[0282] 2 5 1 Elastic member (First elastic member)

[0283] 2 6 1 Retaining member

[0284] 2 7 1 Elastic member (Second elastic member)

[0285] 3. Opening / Closing Member (Third Opening / Closing Member)

[0286] 3 ○ 1 Housing

[0287] 3 1 1

[0288] 3 2 1 Piston

[0289] 3 3 1 Biasing member

[0290] P! Port

[0291] P2 port

[0292] P3 port P4 port

[0293] S ! 1st liquid chamber S 2 2nd liquid chamber S 3 1st internal space S 4 2nd internal space

Claims

[Document Name] Scope of Claim

1. A damping device (100) 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, Housing (201) and, A first piston (221) slidably provided within the housing (201), and a first liquid chamber (S1) which is a space within the housing (201) on one side in the sliding direction of the first piston (221), and which communicates with the discharge side of the pump (36) and the master cylinder (13), respectively. The space within the housing (201) is the space on the other side of the sliding direction relative to the first piston (221), and is the second liquid chamber (S2) which communicates with the master cylinder (13), A first internal space (S3) is formed inside the first piston (221) and opens to the first liquid chamber (S1), A cylindrical first elastic member (251) is provided in the first internal space (S3) and has a hole (251a) that opens at least to the first liquid chamber (S1) side, A first opening / closing member (241) opens and closes the space between the first liquid chamber (S1) and the first internal space (S3), Equipped with, When the pump (36) is driven while the brakes are being applied, the first piston (221) moves toward the first liquid chamber (S1), causing the first opening / closing member (241) to open. When the pump (36) is driven while the aforementioned brake operation is not performed, the first piston (221) moves toward the second liquid chamber (S2), causing the first opening / closing member (241) to close. Damping device.

2. A second piston (222) is provided in the first internal space (S3) and is slidable relative to the first piston (221), A second internal space (S4) is formed inside the second piston (222) and opens to the first liquid chamber (S1), Equipped with, The damping device according to claim 1, wherein the first elastic member (251) is provided in the second internal space (S4).

3. The device includes a biasing member (232) that biases the aforementioned second piston (222) toward the aforementioned liquid chamber (S1), The damping device according to claim 2.

4. The first internal space (S3) includes a second elastic member (271) provided in the space on the second liquid chamber (52) side relative to the second piston (222), which elastically deforms in accordance with the sliding of the second piston (222) relative to the first piston (221). The damping device according to claim 2.

5. The first internal space (S3) includes a second opening / closing member (242) that opens and closes the space on the second liquid chamber (S2) side relative to the second piston (222) and the second liquid chamber (S2), When the pump (36) is driven while the aforementioned brake operation is being performed, the second opening / closing member (242) opens and closes in accordance with the sliding of the second piston (222) relative to the first piston (221). When the pump (36) is operating while the aforementioned brake operation is not being performed, the second opening / closing member (242) is in the closed state. The damping device according to claim 2.

6. The system includes a third opening / closing member (300) that opens and closes the gap between the first liquid chamber (S1) and the master cylinder (13) in response to pressure changes in the first liquid chamber (S1). The damping device according to claim 1.

7. A hydraulic control unit comprising a damping device (100) according to any one of claims 1 to 6.

8. A brake system comprising the hydraulic control unit (15) according to claim 7.

Images