Hydraulic control unit

Abstract

The hydraulic control unit of the present invention is a hydraulic control unit for a vehicle braking system, comprising a discharge flow path (140) for discharging brake fluid pressurized by a pump (60), and a pulsation reduction device (80) disposed in the middle of the discharge flow path (140). The pulsation reduction device includes a pressure change suppressor (110) and a throttle valve (120). The capacity of the pressure change suppressor (110) can be changed according to the pressure of the flowing brake fluid. The throttle valve (120) is disposed downstream of the pressure change suppressor (110) in the discharge flow path (140). The throttle valve (120) includes a first housing (121), a first valve body (122), and a first spring. The component (124) has an opening at one end of the first housing (121) and an end face (121a) at the other end. The end face (121a) has a first through hole (121b) for brake fluid to flow into it. The first valve body (122) is movable along the axial direction of the first housing (121) inside the first housing (121). The first spring component (124) applies force to the first valve body (122) toward the first through hole (121b) of the first housing (121). The first valve body (122) has a sealing part (122b) that closes the first through hole (121b) of the first housing (121) and forms a throttling orifice (122ba).

Description

Technical Field

[0001] This invention relates to a brake hydraulic control unit, and more particularly to a hydraulic control unit comprising a pump that hydraulically raises the brake fluid. Background Technology

[0002] Previously, such vehicle brake hydraulic control units were known to have the following components: a base having a solenoid valve or the like installed to control the flow of brake fluid, and a pump mounted on the base, which causes the brake fluid discharged from the wheel cylinder to flow back to the master cylinder, and pressurizes the brake fluid drawn from the master cylinder to the wheel cylinder.

[0003] Furthermore, a brake hydraulic control unit exists where a damper is provided on the pump discharge side to reduce pulsation of the pumped brake fluid. Patent Document 1 discloses a damper with a dome-shaped damper housing, within which a tubular, elastically deformable damping element is provided. According to this damper, the inner or outer surface of the damping element is subjected to the action of the brake fluid, and pressure changes occurring at the brake fluid level can be suppressed. A throttling element is provided downstream of the damper to temporarily store the brake fluid discharged from the pump within the damping element.

[0004] Patent Document 1: Japanese Patent Publication No. 2017-537020.

[0005] To improve the pulsation reduction effect of the shock absorber, it is desirable to ensure the largest possible volume of the damping element. Furthermore, if the brake fluid pressure on the master cylinder side increases, there is a possibility of brake fluid backflow into the shock absorber. To prevent this, it is desirable to install a check valve on the downstream side of the shock absorber, but it is also desirable to ensure the volume of the damping element and to simplify the construction of the throttle valve and check valve as much as possible. Summary of the Invention

[0006] The present invention was made in light of the above-mentioned problems, and its purpose is to improve the construction of the throttle valve and check valve installed downstream of the shock absorber.

[0007] The hydraulic control unit of the present invention is a hydraulic control unit for a vehicle braking system, comprising a discharge flow path and a pulsation reduction device. The discharge flow path is for discharging brake fluid pressurized by a pump. The pulsation reduction device is disposed in the middle of the discharge flow path. The hydraulic control unit is characterized in that the pulsation reduction device comprises a pressure change suppressor and a throttle valve. The capacity of the pressure change suppressor can be changed according to the pressure of the flowing brake fluid. The throttle valve is disposed downstream of the pressure change suppressor in the discharge flow path. The throttle valve comprises a first housing, a first valve body, and a first spring member. One end of the first housing is open, and the other end has an end face. The end face forms a first through hole for brake fluid to flow into. The first valve body is movable axially within the first housing. The first spring member applies force to the first valve body toward the first through hole of the first housing. The first valve body has a sealing portion that closes the first through hole of the first housing and forms a throttle hole.

[0008] Invention Effects

[0009] According to the present invention, a throttle valve can be provided that can also respond to pressure variations of the brake fluid pumped out, ensuring stable operation. Furthermore, by sharing components for the throttle valve and the check valve, assembly processes can be simplified and costs reduced. Attached Figure Description

[0010] Figure 1 This is a diagram illustrating an example of the system structure of a braking system according to an embodiment of the present invention.

[0011] Figure 2 This is a partial cross-sectional view showing an example of the mounting state of the pump and pressure change suppressor of the hydraulic control unit of the braking system according to an embodiment of the present invention.

[0012] Figure 3 This is a conceptual diagram of a pulsation reduction device for a hydraulic control unit of a braking system according to an embodiment of the present invention.

[0013] Figure 4 This is a cross-sectional view of one embodiment of the throttle valve of the hydraulic control unit of the braking system according to an embodiment of the present invention.

[0014] Figure 5 This is an exploded view of one embodiment of the throttle valve of the hydraulic control unit of the braking system according to an embodiment of the present invention.

[0015] Figure 6 This is a cross-sectional view of one embodiment of the throttle valve and check valve of the hydraulic control unit of the braking system according to an embodiment of the present invention. Detailed Implementation

[0016] The hydraulic control unit of the present invention will now be described with reference to the accompanying drawings.

[0017] Furthermore, the following description pertains to a braking system including the hydraulic control unit of the present invention mounted on a four-wheeled vehicle; however, the braking system including the hydraulic control unit of the present invention can also be mounted on other vehicles besides four-wheeled vehicles (two-wheeled vehicles, trucks, buses, etc.). Moreover, the structures and operations described below are examples, and the braking system including the hydraulic control unit of the present invention is not limited to such structures and operations. Additionally, in the figures, the same or similar components or parts are labeled with the same reference numerals, or reference numerals are omitted. Furthermore, detailed construction details are appropriately simplified or omitted in the illustrations.

[0018] <Structure and Operation of Braking System 1>

[0019] The structure and operation of the braking system 1 in this embodiment will be explained.

[0020] Figure 1 This is a diagram illustrating an example of the system structure of a braking system according to an embodiment of the present invention.

[0021] like Figure 1 As shown, the braking system 1 includes a hydraulic circuit 2, which is mounted on the vehicle 1000. The hydraulic circuit 2 has a main flow path 13 connecting the master cylinder 11 and wheel cylinders 12, a secondary flow path 14 for discharging brake fluid from the main flow path 13, and a supply flow path 15 for supplying brake fluid to the secondary flow path 14. Brake fluid is filled in the hydraulic circuit 2. Furthermore, the braking system 1 of this embodiment includes two hydraulic circuits 2a and 2b as hydraulic circuit 2. Hydraulic circuit 2a is a hydraulic circuit that connects the master cylinder 11 to the wheel cylinders 12 of wheels RL and FR via the main flow path 13. Hydraulic circuit 2b is a hydraulic circuit that connects the master cylinder 11 to the wheel cylinders 12 of wheels FL and RR via the main flow path 13. These hydraulic circuits 2a and 2b have the same structure except that the connected wheel cylinders 12 are different.

[0022] At the master cylinder 11, a piston (not shown) is built in, which reciprocates in conjunction with the brake pedal 16, which serves as an input unit of the braking system 1. An assist device 17 is provided between the brake pedal 16 and the piston of the master cylinder 11, assisting the user's pedaling force and transmitting it to the piston. Alternatively, the assist device 17 can be a negative pressure assist device utilizing the engine's negative pressure, or an electric brake booster that controls the hydraulic pressure by moving the piston of the master cylinder 11 along its stroke using the driving force of a motor. Wheel cylinders 12 are located within the brake calipers 18. When the brake fluid pressure in the wheel cylinders 12 increases, the brake pads 19 of the brake calipers 18 are pushed against the rotor 20, braking the wheels.

[0023] The upstream end of the secondary flow path 14 is connected to the middle section 13a of the main flow path 13, and the downstream end of the secondary flow path 14 is connected to the middle section 13b of the main flow path 13. In addition, the upstream end of the supply flow path 15 is connected to the main cylinder 11, and the downstream end of the supply flow path 15 is connected to the middle section 14a of the secondary flow path 14.

[0024] In addition, the upstream side of the auxiliary flow path 14 refers to the upstream side of the brake fluid flow when the pump 41 is driven and the brake fluid flows back from the wheel cylinder to the master cylinder, and the downstream side refers to the downstream side of the brake fluid flow.

[0025] An inlet valve (EV) 31 is provided in the region between the intermediate sections 13b and 13a of the main flow path 13 (the region on the side of the wheel cylinder 12 with reference to the intermediate section 13b). An outlet valve (AV) 32 is provided in the region between the upstream end of the secondary flow path 14 and the intermediate section 14a. A reservoir 33 is provided in the region between the outlet valve 32 and the intermediate section 14a of the secondary flow path 14. The inlet valve 31 is, for example, a solenoid valve that opens when not energized and closes when energized. The outlet valve 32 is, for example, a solenoid valve that closes when not energized and opens when energized.

[0026] Furthermore, a pump 60 is provided in the region between the intermediate section 14a and the downstream end of the secondary flow path 14. The suction side of the pump 60 communicates with the intermediate section 14a. The discharge side of the pump 60 communicates with the downstream end of the secondary flow path 14. In detail, the braking system 1 has a structure in which the suction flow path 142 and the discharge flow path 140, which are part of the secondary flow path 14, are configured as a brake hydraulic control device 50. The suction flow path 142 forms a flow path between the upstream end of the secondary flow path 14 and the suction side of the pump 60, and the discharge flow path 140 forms a flow path between the discharge side of the pump 60 and the downstream end of the secondary flow path 14.

[0027] Here, the hydraulic control unit 50 includes a pulsation reduction device 100 in the discharge flow path to attenuate the pulsation of the brake fluid discharged from the pump 60. The pulsation reduction device 100 includes a pressure change suppressor 110, a throttle valve 120, and a check valve 130. The pressure change suppressor 110 has a built-in pressure suppression element 111 that elastically deforms in response to the pressure of the flowing brake fluid. The throttle valve 120 changes the flow rate of the brake fluid in response to the pressure of the brake fluid flowing out of the pressure change suppressor 110. The check valve 130 prevents brake fluid from flowing back into the pressure change suppressor 110. Alternatively, depending on the type of vehicle and the required braking force, the check valve 130 may be omitted.

[0028] A first switching valve (USV) 35 is provided in the region on the side of wheel cylinder 11, with reference to the midpoint 13b, in the main flow path 13. A second switching valve (HSV) 36 and a damper unit 37 are provided in the supply flow path 15. The damper unit 37 is located in the region between the second switching valve 36 and the downstream end in the supply flow path 15. The first switching valve 35 is, for example, a solenoid valve that opens when not energized and closes when energized. The second switching valve 36 is, for example, a solenoid valve that closes when not energized and opens when energized. Furthermore, the damper unit 37 can be omitted even if the installation space and required pulsation damping characteristics are considered.

[0029] The hydraulic control unit 50 includes at least a housing 51, various components disposed therein, and a controller (ECU) 52. At the brake hydraulic control device 50, the operation of the inlet valve 31, outlet valve 32, pump 60, first switching valve 35, and second switching valve 36 is controlled by the controller 52, thereby controlling the hydraulic pressure of the brake fluid in the wheel cylinder 12. That is, the controller 52 manages the operation of the inlet valve 31, outlet valve 32, pump 60, first switching valve 35, and second switching valve 36.

[0030] The controller 52 can be a single unit, or it can be multiple units. Furthermore, the controller 52 can be mounted on the base 51, or it can be mounted on other components. Additionally, part or all of the control unit 52 can be composed of, for example, a personal computer, a microprocessor unit, or an updatable structure such as firmware, or it can be a program component executed according to instructions from a central processing unit, etc.

[0031] The controller 52 performs, for example, the following hydraulic control actions.

[0032] When the inlet valve 31 is open, the outlet valve 32 is closed, the first switching valve 35 is open and the second switching valve 36 is closed, if the brake pedal 16 of the vehicle 1000 is operated, and if the detection signal of the position sensor (BPS) of the brake pedal 16 and the detection signal of the hydraulic sensor of the hydraulic circuit 2 detects that the hydraulic pressure of the hydraulic circuit 2 is insufficient or there is a possibility of insufficient pressure, the controller 52 starts the active pressure boosting control action.

[0033] During the active boost control operation, the controller 52 keeps the inlet valve 31 open, allowing brake fluid to flow from the middle section 13b of the main flow path 13 to the wheel cylinder 12. Furthermore, the controller 52 keeps the outlet valve 32 closed, thereby restricting the flow of brake fluid from the wheel cylinder 12 to the reservoir 33. Additionally, the controller 52 closes the first switching valve 35, thereby restricting the flow of brake fluid from the master cylinder 11 to the middle section 13b of the main flow path 13 without passing through the pump 60. Furthermore, the controller 52 opens the second switching valve 36, allowing brake fluid to flow from the master cylinder 11 to the middle section 13b of the main flow path 13 via the pump 60. Finally, the controller 52 drives the pump 60, thereby increasing the hydraulic pressure of the brake fluid in the wheel cylinder 12.

[0034] When the insufficient hydraulic pressure in hydraulic circuit 2 is detected to be eliminated or avoided, the controller 52 terminates the active boost control action by opening the first switching valve 35, closing the second switching valve 36, and stopping the drive of the pump 60.

[0035] Here, when pump 60 is driven, the pulsations generated in the brake fluid sometimes travel through the secondary flow path 14 and the main flow path 13 to the wheel cylinder 12. Furthermore, these pulsations are also transmitted to the engine compartment housing the hydraulic control unit 50 of the braking system 1, sometimes generating noise. This noise can sometimes be a factor affecting the level of discomfort felt by the user (driver). Therefore, it is important to reduce the pulsations generated when pump 60 is driven.

[0036] Therefore, in the braking system 1 of this embodiment, specifically in the hydraulic control unit 50, the brake fluid discharged from the pump 60 flows into the pressure change suppressor 110. Furthermore, after the brake fluid flowing into the pressure change suppressor 110 experiences pulsation attenuation due to the pressure suppression element, it passes through the throttle valve 120 and the check valve 130 and is transmitted to the wheel cylinder.

[0037] Therefore, the braking system 1 of this embodiment, namely the hydraulic control unit 50, can reduce the pulsation generated when the pump 60 is driven.

[0038] <Mounting structure of pump 60 and pressure change suppressor 110 to housing 51>

[0039] In this embodiment, an example of the structure of the hydraulic control unit 50 of the braking system 1 when the pump and pressure change suppressor 110 are mounted on the housing 51 will be described.

[0040] Figure 2 This is a partial cross-sectional view showing an example of the mounting state of the pump and pressure change suppressor 110 of the hydraulic control unit of the braking system 1 according to an embodiment of the present invention towards the housing 51. Additionally, Figure 2 This example shows a pump 60 installed at a hydraulic circuit.

[0041] like Figure 2 As shown, a receiving chamber 59 is formed in the shell 51, and a drive shaft for the piston 62 of the pump 60 is disposed in the aforementioned receiving chamber 59. The receiving chamber 59 has a bottom hole formed in the outer wall of the shell 51. In addition, a receiving chamber 53 for receiving the pump 60 is formed in the shell 51. These receiving chambers 53 are stepped through holes that extend from the outer wall of the shell 51 into the receiving chambers 59.

[0042] The pump 60, housed in the receiving chamber 53, includes a pressure cylinder 61 and a piston 62. The pressure cylinder 61 is formed into a bottomed cylindrical shape with a bottom 61b. A connector 72, one end of which is connected to the piston 62, and an annular sealing member 66, connected to the other end of the connector 72, are housed in the pressure cylinder 61. The space surrounded by the inner circumferential surface of the pressure cylinder 61 and the annular sealing member 66 is the pump chamber 63. The piston 62, connector 72, and annular sealing member 66 can reciprocate freely in the axial direction of the pressure cylinder 61. At this time, the annular sealing member 66 prevents brake fluid from leaking from the pump chamber 63 into the inflow chamber 74. The other end 62a of the piston 62 protrudes into the receiving chamber 59.

[0043] Furthermore, a spring 67 is housed in the pressure cylinder 61, between the bottom 61b and the piston 62, i.e., in the pump chamber 63. This spring 67 exerts a force on the annular sealing member 66 towards the inflow chamber, so the piston 62 is always exerted a force towards the receiving chamber 59. Consequently, the end 62a of the piston 62 abuts against an eccentric portion 57 formed by the drive shaft within the receiving chamber 59. The center position of the eccentric portion 57 is eccentric relative to the rotation center of the drive shaft. Therefore, when the drive shaft rotates by means of the motor 40, the eccentric portion 57 rotates eccentrically relative to the rotation center of the drive shaft. That is, the eccentric portion 57 performs an eccentric rotational motion, thereby causing the piston 62, with its end 62a abutting against the eccentric portion 57, to reciprocate axially in the pressure cylinder 61.

[0044] The piston 62 is slidably guided by a guide member 68 provided on the inner circumferential surface of the receiving chamber 53. Furthermore, an annular sealing member 69 is mounted adjacent to the guide member 68 in the receiving chamber 53. This sealing member 69 liquidally seals the outflow from the outer circumferential surface of the piston 62.

[0045] A suction port 72a is formed on the outer peripheral surface of the connector 72. Furthermore, at the end of the connector 72, a suction valve 73 is provided that can freely open and close an opening communicating with the pump chamber 63. This suction valve 73 includes a ball valve 73a that blocks the opening of the connector 72 and a spring 73b that applies force to the ball valve 73a from the pressure cylinder 61 side. Additionally, a cylindrical filter 70 is installed to cover the suction port 72a of the connector 72.

[0046] At the bottom 61b of the pressure cylinder 61, a through hole 61c is formed, connecting the pump chamber 63 and the outside of the pressure cylinder 61. A discharge valve 64 is provided on the opening side of the through hole 61c opposite to the pump chamber 63. The discharge valve 64 includes a ball valve 64a, a valve seat 64b formed around the opening end of the through hole 61c to allow the ball valve 64a to sit and unsitate, and a spring 64c that applies force in the direction that causes the ball valve 64a to sit on the valve seat 64b. The discharge valve 64 is disposed between the pressure cylinder 61 and the cover 65.

[0047] In detail, the cover 65 is installed on the bottom 61b of the pressure cylinder 61, for example, by pressing. A bottomed hole 65a with an opening is formed on the cover 65, facing the through hole 61c of the bottom 61b. The spring 64c of the discharge valve 64 is received in the bottomed hole 65a. Furthermore, the inner diameter of the bottomed hole 65a is larger than the outer diameter of the ball valve 64a. Therefore, when the ball valve 64a is disengaged from the valve seat 64b, it moves into the bottomed hole 65a. That is, when the brake fluid in the pump chamber 63 of the pressure cylinder 61 rises hydraulically, and the force of the brake fluid pushing the ball valve 64a is greater than the force of the spring 64c, the ball valve 64a disengages from the valve seat 64b, and the pump chamber 63 and the bottomed hole 65a of the cover 65 are connected via the through hole 61c. The brake fluid in the pump chamber 63 flows into the bottomed hole 65a. At cover 65, a groove is formed as an outlet (not shown) that connects the outside of cover 65 to a bottom hole 65a. Brake fluid flowing into cover 65 through the bottom hole 65a is discharged from this outlet to the outside of cover 65, i.e., to the outside of pump 60.

[0048] As described above, the pump 60, constructed in this way, is housed in a receiving chamber 53 formed in the housing 51. Specifically, with the annular protrusion 61a formed on the outer periphery of the pressure cylinder 61 abutting against the stepped portion 53a of the receiving chamber 53, the periphery of the opening of the receiving chamber 53 is riveted, thereby fixing the pump 60 inside the receiving chamber 53 of the housing 51.

[0049] When pump 60 is housed in housing chamber 53, a discharge chamber 54 is formed between the outer peripheral surface of pump 60 and the inner peripheral surface of housing chamber 53, communicating with the discharge port of pump 60. That is, discharge chamber 54 is formed in an annular shape on the outer peripheral side of pump 60 in a manner communicating with the discharge port of pump 60. As described later, discharge chamber 54 constitutes part of discharge flow path 140.

[0050] Furthermore, at the pump 60, the space between the annular protrusion 61a of the pressure cylinder 61 and the cover 65 is divided into two spaces by the partition 71. The space closer to the cover 65 than the partition 71 is the discharge chamber 54. Furthermore, the space closer to the protrusion 61a than the partition 71 is the annular flow path 55.

[0051] In this embodiment, when the pump 60 is housed in the receiving chamber 53, an annular flow path 56 is formed between the outer peripheral surface of the pump 60 and the inner peripheral surface of the receiving chamber 53, communicating with the suction port 72a of the pump 60. That is, the annular flow path 56 is formed as an annular space on the outer peripheral side of the pump 60 in a manner communicating with the suction port 72a of the pump 60. The annular flow path 56 is formed between the annular protrusion 61a of the pressure cylinder 61 and the sealing member 69. In other words, the annular flow path 56 is formed on the outer peripheral side of the filter 70, which is provided to cover the opening of the suction port 72a. Thus, brake fluid flowing in from the reservoir 33 enters the connector 72 from the suction port 72a via the annular flow path 56 and the filter 70.

[0052] The discharge chamber 54 is connected to the pressure suppression element 111 of the pressure change suppressor 110 via the connecting pipe 58. Hereinafter, an embodiment of the pressure change suppressor that reduces brake fluid pulsation will be described.

[0053] The pressure change suppressor 110 has a tubular suppressor housing 112 with an open end and a closed end. A tubular pressure suppressor element 113 is disposed inside the suppressor housing 112. The pressure suppressor element 113 also has an open end and a closed end, with the closed end disposed inside the closed end of the suppressor housing 112.

[0054] The open end of the pressure suppression element 113 is fixed to the open end of the suppressor housing 112 by means of an annular mounting component 114.

[0055] The pressure suppressing element 113 is made of an elastomer, which can be foam. The pressure suppressing element 113 is elastically deformable, and its wall thickness can also change elastically. The pressure suppressing element 113 and the suppressor housing 112 are sealed by air or other gases. Furthermore, the inner surface of the pressure suppressing element 113 communicates with the pump's discharge chamber 54 through the connecting pipe 58.

[0056] The pressure suppression element 113 suppresses deformation based on the material properties of the elastic body it is made of. The brake fluid entering the pressure suppression element 113 consumes energy when the pressure suppression element 113 undergoes elastic deformation, thus suppressing pressure changes in the brake fluid.

[0057] <Structure and Operation of Pulsation Reduction Device 100>

[0058] use Figure 3 The hydraulic circuit diagram shown in the figure includes the pulsation reduction device 100 and its surrounding components, and explains the operation of the pulsation reduction device.

[0059] The pulsation reduction device 100 consists of a pressure change suppressor 110, a throttle valve 120, and a check valve 130.

[0060] Throttle valve 120 is a valve capable of changing the flow rate in accordance with the pressure of the brake fluid flowing out of pressure change suppressor 110. For example, if the pressure of the brake fluid flowing out of pressure change suppressor 110 is less than a predetermined pressure, it flows to check valve 130 via throttle flow path 120a. On the other hand, if the pressure of the brake fluid flowing out of pressure change suppressor 110 is greater than or equal to a predetermined pressure, throttle valve 120 opens, and brake fluid flows out from throttle flow path 120a and also from valve flow path 120b.

[0061] The set pressure can be adjusted by appropriately changing the size of the throttling device opening and the valve spring force.

[0062] Thus, until the predetermined pressure is reached, the brake fluid accumulates in the pressure change suppressor 110. As a result, when the brake fluid flowing out of the pressure change suppressor 110 reaches the predetermined pressure, the valve opening of the throttle valve 120 is activated.

[0063] Brake fluid flowing from throttle valve 120 flows to main flow path 13 via check valve 130. Then, if first switching valve 35 is closed and inlet valve 31 is open, brake fluid flows into wheel cylinder 12; if first switching valve 35 is open and inlet valve 31 is closed, brake fluid flows back to master cylinder 11.

[0064] Here, when the hydraulic pressure of the master cylinder 11 or wheel cylinder 12 increases and at least one of the first switching valve 35 and the inlet valve 31 is open, the check valve 130 prevents the brake fluid from flowing back through the main flow path 13. However, if the hydraulic pressure loss in the master cylinder and wheel cylinder caused by the backflow of brake fluid is permissible according to the vehicle-side specifications, the check valve can be omitted.

[0065] Furthermore, as shown in this embodiment, the pressure change suppressor 110 and the throttle valve 120 are separate units, which allows the pressure change suppressor 110 to have a larger volume, thereby further improving the pulsation reduction effect brought about by the pressure change suppressor 110.

[0066] <Structure and Operation of Throttling Valves>

[0067] Figure 4 A cross-sectional view showing a throttle valve 120 according to an embodiment of the present invention.

[0068] also, Figure 5 It is a three-dimensional diagram showing the detailed structure of the throttle valve.

[0069] The throttle valve 120 has a hollow cylindrical first housing 121, a first valve body 122 that can move axially inside the first housing 121, a first spring member 124 that applies force to the first valve body 122 toward a first through hole 121b formed on the end face of the first housing 121, and a cover 123 that blocks the opening of the first housing 121 and forms a flow path for brake fluid.

[0070] The first shell 121 is open at one end and has an end face 121a at the other end, with a first through hole 121b formed therein. The first through hole 121b is formed such that its diameter gradually decreases from the outside to the inside of the end face 121a. An annular stepped portion 121c is formed on the outer periphery of the end face 121a. Furthermore, a sliding groove 121e is formed parallel to the axial direction on the inner wall of the side surface 121d of the first shell 121.

[0071] The sliding groove 121e extends from the opening of the first shell 121 to the front of the end face 121a. In this embodiment, three sliding grooves are arranged at equal intervals along the inner periphery of the side face 121d.

[0072] The first valve body 122 has a hollow sleeve 122a, a first sealing portion 122b that closes the first through hole 121b from the inside of the first housing 121, a support portion 122c formed between the first sealing portion 122b and one end of the sleeve 122a to support the first sealing portion, and a guide 122d formed on the outer wall of the sleeve 122a.

[0073] The first sealing part 122b is formed in a dome shape, and a throttling orifice 122ba is formed on its top portion. The top portion of the first sealing part 122b with the throttling orifice 122ba opens, and the orifice diameter gradually decreases as it moves inward, maintaining a constant orifice diameter from the middle and extending to the inner side of the sealing member (see reference). Figure 4 In this embodiment, the support portion 122c is formed in a fan shape, and three are evenly arranged circumferentially along the end of the sleeve 122a. A gap leading to the interior of the sleeve is formed between each support portion 122c.

[0074] The guide member 122d bulges out from the outer wall of the sleeve 122a while maintaining a constant height and width, extending from one end of the sleeve's opening side parallel to the axis of the first valve body 122 to near the other end of the sleeve 122a. In this embodiment, three guide members 122d are evenly arranged along the circumference of the sleeve 122a. Furthermore, the width and height of the guide member 122d are formed to be slightly smaller and shallower than the width and height of the sliding groove, allowing the guide member 122d to fit into the sliding groove 121e of the first housing 121.

[0075] The sleeve 122a, the first sealing part 122b, the support part 122c, and the guide 122d of the first valve body 122 are integrally formed by resin molding, etc.

[0076] The cover 123 has a circular bottom 123a and a side 123b that stands vertically from the bottom 123a.

[0077] At the bottom 123a, a spring support portion 123aa is formed to support the first spring member 124, and a flow path 123ab for brake fluid flow is formed around it. In addition, at the side portion 123b, an opening 123ba is formed for brake fluid to flow out to the auxiliary flow path.

[0078] Next, the operation of the throttle valve will be explained.

[0079] Active boost control is initiated, causing brake fluid discharged from pump 60 to accumulate in pressure change suppressor 110, and then reach the first through-hole 121b of the first housing 121 via connecting pipe 58. When the force (F1s) pushing the first valve body 122 by the first spring member 124 is greater than the force (F1p) pushing the first valve body 122 downward by the hydraulic pressure of the brake fluid on the first seal 122b, the first seal 122b remains in a state of blocking the first through-hole 121b, so brake fluid only flows into the interior of the first valve body 122 through the throttle orifice 122ba. When the amount of brake fluid accumulated in pressure change suppressor 110 increases and F1p becomes greater than F1s, the first valve body 122 is pushed downward. In this way, the first sealing part 122b leaves the first through hole 121b, so the brake fluid that reaches the first through hole 121b flows into the interior of the first valve body 122 through the gap between the support parts 122c.

[0080] Then, the brake fluid flows through the flow path 123ab of the cover 123 and flows out from the opening 123ba to the main flow path 13.

[0081] In this way, the first sealing portion 122b of the first valve body 122 opens and closes the first through hole 121b, so the flow rate of the brake fluid can be controlled in accordance with the hydraulic pressure of the brake fluid flowing into the throttle valve 120. In addition, when the first valve body 122 is pushed downward, the guide 122d moves along the sliding groove 121e, so the axial movement of the first valve body can be stabilized.

[0082] <Structure and Operation of Throttling Valves and Check Valves>

[0083] use Figure 6 The structure and operation of the throttle valve 120 and check valve 130 of the pulsation reduction device 100 of the second embodiment of the present invention will be described.

[0084] Furthermore, descriptions of structures identical to the throttle valve in the first embodiment are omitted or simplified.

[0085] The throttle valve 130 has a hollow cylindrical second housing 131, a second valve body 132 that can move axially inside the second housing 131, a second spring member 134 that applies force to the second valve body 132 toward the second through hole 131b formed on the end face 131a of the second housing 131, and a cover 133 that blocks the opening of the second housing 131 and forms a flow path for brake fluid.

[0086] The second housing 131 is open at one end and has an end face 131a at the other end, with a second through hole 131b formed therein. The second through hole 131b is formed such that its diameter gradually decreases from the outside to the inside of the end face 131a. An annular stepped portion 131c is formed on the outer periphery of the end face. Furthermore, a sliding groove 131e is formed parallel to the axial direction on the inner wall of the side surface 131d of the second housing 131. The sliding groove 131e extends from the opening of the second housing 131 to near the front of the end face 131a. Similar to the sliding groove 121e of the throttle valve, there are three sliding grooves 131e, which are equally spaced along the inner periphery of the side surface 131d.

[0087] The second valve body 132 has a hollow sleeve 132a, a second sealing portion 132b that closes the second through hole 131b from the inside of the second housing 131, a support portion 132c formed between the second sealing portion 132b and one end of the sleeve 132a to support the second sealing portion 132b, and a guide 132d formed on the outer wall of the sleeve 132a.

[0088] The second sealing part 132b is formed in a dome shape. Unlike the first sealing part 122b of the first valve body, it does not have a throttling orifice 122ba or other holes.

[0089] The support portion 132c is formed in a fan shape, and three are evenly arranged circumferentially along the end of the sleeve 132a. A gap is formed between each support portion 132c to lead into the interior of the sleeve 132a.

[0090] The guide member 132d bulges out from the outer wall of the sleeve 132a and extends from the opening side of the sleeve toward the sealing side, parallel to the axis of the second valve body 132. In this embodiment, three guide members 132d are evenly arranged along the circumference of the sleeve 132a.

[0091] The cover 133 has a circular bottom and a side that stands vertically from the bottom. At the bottom, a spring support portion supporting the second spring member 134 is formed, and a flow path for brake fluid flow is formed around it. Furthermore, an opening is formed on the side for allowing brake fluid to flow into a secondary flow path.

[0092] use Figure 6 b. The assembly status of the throttle valve 120, check valve 130 and cover 133 is described.

[0093] The opening of the throttle valve fits into the stepped portion 131c formed at the second housing 131 of the check valve 130, thus assembling them together. At this time, the end of the first spring member 124 of the throttle valve 120 is provided at the end face 131a of the second housing 131. Therefore, by means of the force of the first spring member 124, the first valve body 122 is pushed up, so the opening of the first valve body 122 is slightly separated from the end face of the second housing 131. In addition, to prevent liquid from leaking between the first and second housings, an O-ring (not shown) or the like can be assembled to the stepped portion of the second housing and fitted together.

[0094] The opening of the second housing 131 fits into the side of the cover 133, thereby assembling the check valve 130 and the cover 133. The end of the second spring member 134 is provided at the spring support portion of the cover 133, and the second valve body 132 is pushed up by the force of the second spring member 134, so that the second valve body 132 is slightly separated from the spring support portion.

[0095] Next, the operation of the throttle valve and check valve of the pulsation reduction device in the second embodiment will be explained.

[0096] Brake fluid flowing from the inside of the throttle valve 120 into the opening passes through the second through hole 131b of the check valve 130 to the second seal 132b. If the force (F2p) that pushes the second valve body 132 downward by means of the hydraulic pressure on the second seal 132b becomes greater than the force (F2s) that pushes the second valve body 132 upward by means of the second spring member 134, the second valve body moves downward.

[0097] At this time, brake fluid flows into the interior of the second valve body 132 through the gap between the support portions 132c. In addition, the spring constant of the first spring component 124 of the throttle valve 120 is greater than the spring constant of the second spring component 134 of the check valve 130, so the second valve body 132 is pushed downward by a hydraulic pressure that is less than the hydraulic pressure necessary for the first valve body to move downward.

[0098] After that, the brake fluid flows out from the opening of the cover 133 through the flow path of the cover 133.

[0099] Even if the hydraulic pressure of the main flow path 13 is high and the brake fluid flows back into the interior of the second valve body 132, the second sealing part 132b will also close the second through hole 131b, so the brake fluid will not flow back into the throttle valve.

[0100] Furthermore, since the first housing 121 and the second housing 131, the first valve body 122 and the second valve body 132 are formed with common dimensions, shapes and materials, manufacturing costs can be reduced.

[0101] Explanation of reference numerals in the attached figures

[0102] 1 Braking system, 2 Hydraulic circuit, 11 Master cylinder, 12 Wheel cylinder, 13 Main flow path, 14 Secondary flow path, 15 Supply flow path, 35 First switching valve, 36 Second switching valve, 40 Motor, 54 Discharge chamber, 60 Pump, 100 Pulsation reduction device, 110 Pressure change suppressor, 120 Throttle valve, 120a Throttle flow path, 120b Valve flow path, 121 First housing, 121a End face, 121c Stepped portion, 121d Side, 121e Sliding groove, 122 First valve body, 122a Sleeve, 122b First sealing portion, 122ba Throttle orifice, 122c Support portion, 122d Guide, 123 Cover, 123a Bottom, 123aa Spring support portion, 123ab Flow path, 123b Side, 123ba opening, 124 first spring component, 130 check valve, 131 second housing, 131a end face, 131b second through hole, 131c step, 131d side, 131e sliding groove, 132 second valve body, 132a sleeve, 132b second sealing part, 132c support part, 132d guide, 133 cover, 134 second spring component, 140 discharge flow path, 142 suction flow path.

Claims

1. A hydraulic control unit comprising a discharge flow path (140) and a pulsation reduction device (100), wherein the discharge flow path (140) is for discharging brake fluid pressurized by a pump (60), and the pulsation reduction device (100) is disposed midway through the discharge flow path (140), the hydraulic control unit being characterized in that, The aforementioned pulsation reduction device (100) includes a pressure change suppressor (110) and a throttle valve (120). The capacity of the aforementioned pressure change suppressor (110) can be changed according to the pressure of the flowing brake fluid. The aforementioned throttle valve (120) is positioned downstream of the aforementioned pressure change suppressor (110) in the aforementioned discharge flow path (140). The aforementioned throttle valve (120) includes a first housing (121), a first valve body (122), and a first spring component (124). The aforementioned first housing (121) has an opening at one end and an end face (121a) at the other end, wherein the aforementioned end face (121a) has a first through hole (121b) for brake fluid to flow in. The aforementioned first valve body (122) is capable of moving axially along the aforementioned first housing (121) within the aforementioned first housing (121). The aforementioned first spring component (124) applies force to the aforementioned first valve body (122) in the direction of the aforementioned first through hole (121b) of the aforementioned first housing (121). The aforementioned first valve body (122) includes a sealing portion (122b), which closes the aforementioned first through hole (121b) of the aforementioned first housing (121) and forms a throttling orifice (122ba). The aforementioned first valve body (122) has a hollow sleeve (122a) and a support portion (122c) provided at one end of the aforementioned sleeve (122a) to support the aforementioned sealing portion (122b).

2. The hydraulic control unit as described in claim 1, characterized in that, The aforementioned first valve body (122) has a guide (122d) at the aforementioned sleeve (122a) to guide the aforementioned axial movement, and the aforementioned first housing (121) has a sliding groove (121e) on the inner wall facing the aforementioned sleeve (122a) for engaging the aforementioned guide (122d).

3. The hydraulic control unit as described in claim 1 or 2, characterized in that, The aforementioned pulsation reduction device (100) has a check valve (130) downstream of the aforementioned throttle valve (120). The aforementioned check valve (130) includes a second housing (131), a second valve body (132), and a second spring component (134). The aforementioned second shell (131) has an opening at one end and an end face at the other end, with a second through hole (131b) formed on the end face for brake fluid to flow in. The aforementioned second valve body (132) is capable of moving axially along the aforementioned second housing (131) within the aforementioned second housing (131). The aforementioned second spring component (134) applies force to the aforementioned second valve body (132) in the direction of the aforementioned second through hole (131b) of the aforementioned second housing (131). The aforementioned second valve body (132) has a second sealing part (132b), which closes the aforementioned second through hole (131b) of the aforementioned second housing (131).

4. The hydraulic control unit as described in claim 3, characterized in that, The spring constant of the first spring component (124) is greater than the spring constant of the second spring component (134).

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