Pulsation reducing device and brake hydraulic pressure control device of vehicle equipped with the same

Abstract

This invention relates to a pulsation reduction device installed in a vehicle's hydraulic braking system. The pulsation reduction device includes: a first chamber (A) into which brake hydraulic fluid is input from a brake hydraulic circuit (2); a second chamber (B) into which brake hydraulic fluid is output to the brake hydraulic circuit (2); and a connecting portion (80a) connecting the first chamber (A) and the second chamber (B); the connecting portion (80a) includes: a first valve body (86) movable to a non-connected position seated on a first valve seat (85b) without connecting the first chamber (A) and the second chamber (B), and a connected position dismounted from the first valve seat (85b) and connecting the first chamber (A) and the second chamber (B); and a force-applying member for applying force to the first valve body (86) towards the first valve seat (85b). b) Lateral force application; the force application components include a second force application component (89) and a third force application component (90) different from the second force application component (89); the second force application component (89) has a hysteresis characteristic that the recovery force (p) in the loading process and the recovery force (p) in the unloading process are different magnitudes when the displacement (s) is the same in the loading process and the unloading process; the third force application component (90) has a characteristic that the recovery force (p) in the unloading process when the displacement (s) is the same as that of the second force application component (89) is larger than the recovery force in the unloading process of the second force application component (89) when the displacement (s) is the same.

Description

Technical Field

[0001] This invention relates to a pulsation reduction device for reducing the pulsation of brake hydraulic fluid in a vehicle's brake hydraulic circuit, and a brake hydraulic control device for a vehicle equipped with the pulsation reduction device. Background Technology

[0002] Conventionally, brake hydraulic control devices for controlling the brake hydraulic fluid in a vehicle's braking system have the following structure: a brake hydraulic circuit that connects the brake hydraulic fluid between the master cylinder and wheel cylinders of the vehicle, a pump that increases the brake hydraulic fluid in the brake hydraulic circuit, and a solenoid valve that connects and disconnects the brake hydraulic fluid in the brake hydraulic circuit. When there is a need to increase the brake hydraulic fluid supplied to the wheel cylinders, the pump is driven and controlled to increase the brake hydraulic fluid supplied to the wheel cylinders regardless of the driver's operation of the vehicle's brake pedal (for example, see Patent Document 1, etc.).

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2017-061246 Summary of the Invention

[0006] The problem that the invention aims to solve

[0007] In the brake hydraulic control device described in Patent Document 1, there is a concern that pulsations in the brake hydraulic fluid generated by the pump propagate from the braking system to the vehicle's engine compartment, potentially causing unpleasant or uncomfortable noise for the vehicle's driver, passengers, or people outside the vehicle. In contrast, this brake hydraulic control device features a variable-volume chamber with a diaphragm that elastically deforms with changes in brake hydraulic fluid, which reduces the pulsations in the brake hydraulic fluid generated by the pump. However, in recent braking systems, there are concerns about increased brake hydraulic fluid pulsations due to higher pump speeds, thus requiring further reduction in brake hydraulic fluid pulsations.

[0008] The present invention was made in light of the aforementioned issues, and its purpose is to provide a brake hydraulic control device capable of reducing brake hydraulic pulsation in the brake hydraulic circuit of a vehicle.

[0009] Methods used to solve problems

[0010] The pulsation reduction device involved in this invention is a pulsation reduction device (37, 80) installed in the braking system of a vehicle equipped with a brake hydraulic circuit (2) that supplies brake hydraulic fluid to a wheel cylinder (12) and a pump (60) that raises the brake hydraulic fluid, and reduces the pulsation of the brake hydraulic fluid in the brake hydraulic circuit (2). It has the following structure: It includes: a first chamber (A) into which brake hydraulic fluid is input from the aforementioned brake hydraulic circuit (2); a second chamber (B) into which brake hydraulic fluid is output to the aforementioned brake hydraulic circuit (2); and a connecting part (80a) connecting the aforementioned first chamber (A) and the aforementioned second chamber (B); the aforementioned connecting part (80a) includes: a valve body (86) that moves to a non-connected position seated on a valve seat (85b) without connecting the aforementioned first chamber (A) and the aforementioned second chamber (B), and a valve body (86) that moves from the aforementioned valve seat (85b) to a non-connected position. The connection position connecting the first chamber (A) and the second chamber (B) is removed from the seat; and the force-applying components (89, 90) apply force to the valve body (86) towards the valve seat (85b); the force-applying components (89, 90) include a first force-applying component (89) and a second force-applying component (90) different from the first force-applying component (89); the first force-applying component (89) has a hysteresis characteristic that the recovery force during the loading process and the recovery force during the unloading process are different magnitudes when the displacement is the same during the loading process and the unloading process; the second force-applying component (90) has a characteristic that the recovery force during the unloading process when the displacement is the same as that of the first force-applying component (89) is greater than the recovery force during the unloading process of the first force-applying component (89) when the displacement is the same.

[0011] According to this structure, by means of the first force-applying component (89) and the second force-applying component (90), the fluctuation of brake hydraulic pressure inside the pulsation reduction device is absorbed, thereby reducing the pulsation of brake hydraulic pressure in the vehicle's brake hydraulic circuit.

[0012] Furthermore, the present invention may have only the inventive specific matter described in the claims of the present invention, or it may have a structure other than the inventive specific matter described in the claims of the present invention. Attached Figure Description

[0013] Figure 1 This is a diagram used to illustrate the structure of the braking system involved in the implementation method.

[0014] Figure 2 This diagram is used to illustrate the pump and the pulsation reduction device.

[0015] Figure 3 This diagram is used to illustrate the pulsation reduction device (pump non-driven state).

[0016] Figure 4 This diagram is used to illustrate the pulsation reduction device (pump-driven state).

[0017] Figure 5 This diagram is used to illustrate the pulsation reduction device (pump-driven state).

[0018] Figure 6 It is a diagram used to illustrate the relationship between the displacement of the force-applying component and the restoring force. Detailed Implementation

[0019] Examples of embodiments of the brake hydraulic control device and the brake system equipped with the brake hydraulic control device according to the present invention will be described using the accompanying drawings. Hereinafter, similar or identical descriptions may be appropriately simplified or omitted. Furthermore, in the figures, reference numerals may be omitted or the same reference numerals may be given to similar or identical components or parts. Additionally, detailed construction details may be appropriately simplified or omitted from the illustrations.

[0020] Furthermore, the structure and operation of the embodiments described below are merely examples. The present invention is not limited to such structures and operations, and appropriate modifications can be made within the scope of the present invention. For example, the braking system 1 and brake hydraulic control device 50 of this embodiment are structures mounted on a four-wheeled vehicle, but the brake hydraulic control device and braking system equipped with such a brake hydraulic control device according to the present invention can also be structures mounted on other vehicles besides four-wheeled vehicles, such as unicycles, two-wheeled vehicles, three-wheeled vehicles, trucks, buses, construction vehicles, etc.

[0021] [Regarding the braking system 1]

[0022] based on Figure 1 and Figure 2 The braking system 1 according to this embodiment will be described. The braking system 1 is a system for controlling the braking of each wheel of a four-wheeled vehicle 100.

[0023] like Figure 1 As shown, the braking system 1 includes: a master cylinder 11, which has a built-in piston (not shown) that reciprocates in conjunction with the brake pedal 16 installed in the vehicle; wheel cylinders 12, which are provided corresponding to each wheel of the four-wheeled vehicle to generate braking force for each wheel; and a brake hydraulic control device 50, which independently controls the brake hydraulic pressure supplied to each wheel cylinder 12 based on the state of the braking operation performed by the driver of the vehicle.

[0024] A force amplification device 17 is clamped between the brake pedal 16 and the piston of the master cylinder 11 to multiply the pedal force transmitted to the driver and transfer it to the piston of the master cylinder 11. Wheel cylinders 12 are mounted on the brake calipers 18. If the brake fluid pressure in the wheel cylinder 12 increases, the brake pads 19 of the brake calipers 18 are pressed against the rotor 20, and the wheels are braked.

[0025] The brake hydraulic control device 50 includes a base 51, which forms a brake fluid hydraulic circuit 2 that hydraulically connects the master cylinder 11 and the wheel cylinder 12. Inside the base 51, the hydraulic circuit 2 includes a main flow path 13 that connects the master cylinder 11 and the wheel cylinder 12, a secondary flow path 14 that drains brake fluid from the main flow path 13, and a supply flow path 15 that supplies brake fluid to the secondary flow path 14. The hydraulic circuit 2 is filled with brake fluid.

[0026] Furthermore, the braking system 1 according to this embodiment has 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 wheel cylinders 12 they connect to are different.

[0027] The upstream end of the secondary flow path 14 is connected to the intermediate portion 13a of the main flow path 13, and the downstream end of the secondary flow path 14 is connected to the intermediate portion 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 intermediate portion 14a of the secondary flow path 14.

[0028] In addition, the upstream side of the auxiliary flow path 14 refers to the upstream side of the brake fluid flow when the pump 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.

[0029] A filling valve (EV) 31 is provided in the region between intermediate sections 13b and 13a in the main flow path 13 (the region on the side of wheel cylinder 12 with reference to intermediate section 13b). A release valve (AV) 32 is provided in the region between intermediate sections 13a and 14a in the secondary flow path 14. An accumulator 33 is provided in the region between the release valve 32 and intermediate section 14a in the secondary flow path 14. The filling valve 31 is, for example, a solenoid valve that opens when not energized and closes when energized. The release valve 32 is, for example, a solenoid valve that closes when not energized and opens when energized.

[0030] Furthermore, a pump 60 is provided in the region between intermediate section 14a and intermediate section 13b in the secondary flow path 14. The suction side of the pump 60 communicates with intermediate section 14a. The discharge side of the pump 60 communicates with intermediate section 13b of the secondary flow path 14. In detail, the braking system 1, as a structure of the brake hydraulic control device 50, includes a suction flow path 142 and a discharge flow path 140, which are part of the secondary flow path 14. The suction flow path 142 forms the flow path between intermediate section 13a of the secondary flow path 14 and the suction side of the pump 60, and the discharge flow path 140 forms the flow path between the discharge side of the pump 60 and intermediate section 13b of the secondary flow path 14.

[0031] Here, the brake hydraulic control device 50 has a pulsation reduction section 80 on the ejection flow path 140 to attenuate the pulsation of the brake fluid ejected from the pump 60. Specifically, the inflow opening 91b of the pump 60 ejection side and the pulsation reduction section 80 into which the brake fluid flows (see reference) Figure 2 The brake fluid is connected to the outlet opening 91c (refer to) where it flows out from the brake fluid temporarily stored in the pulsation reduction section 80. Figure 2 It is connected to the intermediate part 13b of the auxiliary flow path. In addition, in the following description, the flow path between the pump's ejection side and the inlet opening 91b is referred to as the first ejection flow path 140a, and the flow path between the outlet opening 91c and the intermediate part 13b of the auxiliary flow path is referred to as the second ejection flow path 140b.

[0032] A first switching valve (USV) 35 is provided in the area on the master cylinder 11 side of the main flow path 13, with the intermediate section 13b as a reference. 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 area between the second switching valve 36 and the intermediate section 13b 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, this embodiment shows a structure where both the ejection flow path 140 and the supply flow path 15 have a damper unit 37 and a pulsation reduction section 80 as pulsation reduction devices; however, depending on the installation space and the required pulsation attenuation characteristics, the damper unit 37 may not be provided.

[0033] A filling valve 31, a release valve 32, an accumulator 33, a pump 60, a first switching valve 35, a second switching valve 36, a damping unit 37, and a pulsation reduction section 80 are disposed on a base 51, which internally forms flow paths for constituting a main flow path 13, a secondary flow path 14, and a supply flow path 15. The components (filling valve 31, release valve 32, accumulator 33, pump 60, first switching valve 35, second switching valve 36, damping unit 37, and pulsation reduction section 80) can be centrally disposed in one base 51, or they can be separately disposed in multiple bases 51.

[0034] The brake hydraulic control device 50 is composed of at least a base 51, various components disposed on the base 51, and a controller 52. In the brake hydraulic control device 50, the hydraulic pressure of the brake fluid in the wheel cylinder 12 is controlled by the controller 52 through the control of the operation of the filling valve 31, the release valve 32, the pump 60, the first switching valve 35, and the second switching valve 36. That is, the controller 52 manages the operation of the filling valve 31, the release valve 32, the pump 60, the first switching valve 35, and the second switching valve 36.

[0035] The controller 52 can be a single unit or multiple units. Furthermore, the controller 52 can be mounted on the base 51 or other components. Additionally, part or all of the controller 52 can be composed of, for example, a microcomputer, a microprocessor unit, or an updatable element such as firmware, or a program module executed by instructions from a CPU, etc.

[0036] In addition to well-known hydraulic control actions (ABS control actions, ESP control actions, etc.), controller 52 also performs the following hydraulic control actions.

[0037] If, with the filling valve 31 open, the release valve 32 closed, the first switching valve 35 open, and the second switching valve 36 closed, when the brake pedal 16 of the vehicle 100 is operated, and the controller 52 detects a lack of hydraulic pressure or a possibility of insufficient hydraulic pressure in the hydraulic circuit 2 based on the detection signal from the position sensor of the brake pedal 16 and the detection signal from the hydraulic sensor of the hydraulic circuit 2, then the controller 52 begins an active pressurization control action.

[0038] In the active boost control operation, the controller 52 allows brake fluid to flow from the intermediate section 13b of the main flow path 13 to the wheel cylinder 12 by keeping the fill valve 31 open. Furthermore, the controller 52 restricts the flow of brake fluid from the wheel cylinder 12 to the accumulator 33 by keeping the release valve 32 closed. Additionally, the controller 52 restricts the flow of brake fluid from the master cylinder 11 to the intermediate section 13b of the main flow path 13 without passing through the pump 60 by closing the first switching valve 35. Furthermore, the controller 52 allows the flow of brake fluid from the master cylinder 11 to the intermediate section 13b of the main flow path 13 via the pump 60 by opening the second switching valve 36. Additionally, the controller 52 increases the hydraulic pressure of the brake fluid in the wheel cylinder 12 by driving the pump 60.

[0039] If 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.

[0040] Here, if pump 60 is driven, there is a concern that pulsations generated in the brake fluid will be transmitted to wheel cylinders 12 via the secondary flow path 14 and the main flow path 13. Furthermore, these pulsations are also transmitted to the engine compartment housing the brake hydraulic control device 50, which houses the brake system 1, raising concerns about noise generation. There is also concern about the extent to which this noise might cause unpleasantness to the driver or others. Therefore, it is important to reduce the pulsations generated when pump 60 is driven.

[0041] Therefore, in the brake hydraulic control device 50 of the brake system 1 of this embodiment, the brake fluid ejected from the pump 60 flows into the pulsation reduction section 80. Then, after the pulsation of the brake fluid flowing into the pulsation reduction section 80 is reduced, it flows downstream of the pulsation reduction section 80. Therefore, the brake hydraulic control device 50 of this embodiment can reduce the pulsation generated by the driving of the pump 60.

[0042] Furthermore, in the aforementioned active boost control, when the user operates the brake pedal 16, the pump 60 is driven when the second switching valve 36 is open. Therefore, pulsations generated in the brake fluid are transmitted to the brake pedal 16 via the supply path 15 and the master cylinder 11, causing an unpleasant sensation for the user. Therefore, the brake hydraulic control device 50 of this embodiment is preferably as follows: Figure 1 As shown, it has a damping unit 37. The damping unit 37 can reduce the pulsation of brake fluid transmitted from the pump 60 to the brake pedal 16.

[0043] Alternatively, when the damping unit 37 is provided in the braking system 1 without the booster device 17, the damping unit 37 can be located in the region between the upstream end of the supply flow path 15 and the second switching valve 36. By providing the damping unit 37 at such a location, when the user depresses the brake pedal 16, brake fluid can flow into the damping unit 37, reducing the reaction force of the brake fluid in the hydraulic circuit 2 transmitted to the brake pedal 16. Therefore, when the user operates the brake pedal, the same amount of brake pedal 16 operation is obtained as in the braking system 1 with the booster device 17. Thus, the user can obtain the same user experience in the braking system 1 without the booster device 17 as in the braking system 1 with the booster device 17.

[0044] [Regarding Pump 60]

[0045] based on Figure 2 The pump 60 involved in this embodiment will be described. Figure 2 This is a partial cross-sectional view of the base 51 of the brake hydraulic control device 50, in which the pump 60 and the pulsation reduction section 80 are mounted, and the drive shaft 57 that drives the piston 62 of the pump 60 is removed. Additionally, Figure 2 The double-dotted line in the figure represents the drive shaft 57 and the eccentric portion 57a ​​formed on the drive shaft 57.

[0046] like Figure 2 As shown, a receiving chamber 59 is formed in the base 51, and the receiving chamber 59 is provided with a drive shaft 57 that drives the piston 62 of the pump 60. The receiving chamber 59 has a bottom hole formed in the outer wall of the base 51. In addition, a receiving chamber 53 for receiving the pump 60 is formed in the base 51. These receiving chambers 53 are stepped through holes that extend from the outer wall of the base 51 into the receiving chambers 59.

[0047] The pump 60, housed in the housing chamber 53, includes a cylinder 61 and a piston 62. The cylinder 61 is formed into a bottomed cylindrical shape with a bottom 61b. One end of the piston 62 is housed within the cylinder 61. The space enclosed by the inner circumferential surface of the cylinder 61 and the aforementioned end of the piston 62 forms the pump chamber 63. The piston 62 can reciprocate freely in the axial direction of the cylinder 61. Furthermore, the end portion 62a of the other end of the piston 62 protrudes into the housing chamber 59. An annular sealing member 66 is installed on the portion of the piston 62 housed in the cylinder 61. This sealing member 66 prevents brake fluid leakage between the outer circumferential surface of the piston 62 and the inner circumferential surface of the cylinder 61.

[0048] Furthermore, a spring 67 is housed in the cylinder 61, between the bottom 61b and the piston 62, i.e., in the pump chamber 63. Normally, this spring 67 exerts a force on the piston 62 towards the housing chamber 59. Consequently, the end 62a of the piston 62 abuts against an eccentric portion 57a, which is formed within the housing chamber 59 of the drive shaft 57. The center of the eccentric portion 57a ​​is eccentric relative to the rotation center of the drive shaft 57. Therefore, if the drive shaft 57 is rotated by a drive source (not shown), the eccentric portion 57a ​​undergoes an eccentric rotational motion relative to the rotation center of the drive shaft 57. That is, through the eccentric rotational motion of the eccentric portion 57a, the piston 62, whose end 62a abuts against the eccentric portion 57a, reciprocates axially in the cylinder 61.

[0049] The portion of piston 62 protruding from cylinder 61 is slidably guided by guide member 68, which is disposed on the inner circumferential surface of receiving chamber 53. Furthermore, an annular sealing member 69 is installed adjacent to guide member 68 in receiving chamber 53. This sealing member 69 liquid-tightly seals the flow from the outer circumferential surface of piston 62.

[0050] The piston 62 has a bottomed hole 62b formed axially, opening onto the pump chamber 63 side of the cylinder 61. The piston 62 also has a suction port 62c, which serves as a through hole communicating with the bottomed hole 62b on its outer circumferential surface. Furthermore, the piston 62 is provided with a suction valve (not shown) that can freely close the opening of the bottomed hole 62b. This suction valve includes a ball valve that closes the opening of the bottomed hole 62b and a spring that applies force to the ball valve from the cylinder 61 side. Additionally, a cylindrical filter 70 is installed at the piston 62 side end of the cylinder 61, covering the opening of the suction port 62c of the piston 62.

[0051] A through hole 61c is formed at the bottom 61b of cylinder 61, communicating with the outside of pump chamber 63. A spray valve 64 is provided on the opening side of the through hole 61c opposite to pump chamber 63. The spray valve 64 includes a ball valve 64a, a valve seat 64b formed around the opening end of the through hole 61c and capable of seating / unseatment of the ball valve 64a, and a spring 64c that applies force to the ball valve 64a in the direction of its seat on the valve seat 64b. The spray valve 64 is disposed between cylinder 61 and cover 65.

[0052] In detail, the cover 65 is installed at the bottom 61b of the cylinder 61 by means of a press-fit, for example. The cover 65 has a bottomed hole 65a with an opening opposite to the through hole 61c in the bottom 61b. Furthermore, the spring 64c of the ejector valve 64 is housed in the bottomed hole 65a. Moreover, 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 hydraulic pressure of the brake fluid in the pump chamber 63 of the cylinder 61 rises, and the force of the brake fluid pushing the ball valve 64a becomes greater than the force of the spring 64c, the ball valve 64a disengages from the valve seat 64b, and the pump chamber 63 communicates with the bottomed hole 65a of the cover 65 via the through hole 61c. Then, the brake fluid in the pump chamber 63 flows into the bottomed hole 65a. In the cover 65, a groove is formed as the nozzle 65b, which communicates the outside of the cover 65 with the bottom hole 65a. The brake fluid flowing into the bottom hole 65a of the cover 65 is sprayed from the nozzle 65b to the outside of the cover 65, that is, the outside of the pump 60 (for example, to the continuous flow path of the pulsation reduction section 80).

[0053] The pump 60 thus constructed is housed in the housing chamber 53 formed in the base 51 as described above. Specifically, the pump 60 is fixed in the housing chamber 53 of the base 51 by closing the periphery of the opening of the housing chamber 53 while the annular protrusion 61a formed on the outer periphery of the cylinder 61 abuts against the stepped portion 53a of the housing chamber 53.

[0054] When the pump 60 is housed in the housing chamber 53, an ejection chamber 54 is formed between the outer peripheral surface of the pump 60 and the inner peripheral surface of the housing chamber 53, serving as a space communicating with the ejection outlet 65b of the pump 60. That is, the ejection chamber 54 is formed annularly on the outer peripheral side of the pump 60 to communicate with the ejection outlet 65b of the pump 60. The ejection chamber 54 constitutes part of the first ejection flow path 140a, as described later.

[0055] Furthermore, in the pump 60, the space between the annular protrusion 61a of the 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 then becomes the ejection chamber 54. Furthermore, the space closer to the protrusion 61a than the partition 71 becomes the annular flow path 55. Additionally, as... Figure 2 As shown, in this embodiment, the partition 71 is formed by a protrusion that protrudes in an annular shape on the outer peripheral surface of the cylinder 61 and an O-ring provided on the protrusion. However, the structure of the partition 71 is arbitrary as long as it can divide the space between the annular protrusion 61a of the cylinder 61 and the cover 65 into two spaces. For example, the partition 71 may be formed solely by the protrusion that protrudes in an annular shape on the outer peripheral surface of the cylinder 61. Furthermore, the partition 71 may be formed solely by the O-ring provided on the outer peripheral surface of the cylinder 61.

[0056] Furthermore, in this embodiment, when the pump 60 is housed in the housing 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 housing chamber 53, serving as a space communicating with the suction port 62c of the pump 60. That is, the annular flow path 56 is formed in a ring shape on the outer peripheral side of the pump 60 to communicate with the suction port 62c of the pump 60. The annular flow path 56 is formed between the annular protrusion 61a of the 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 in a manner that covers the opening of the suction port 62c.

[0057] The annular flow path 56 interacts with the substrate 51 via an internal flow path (not shown). Figure 1 The intermediate portion 14a of the secondary flow path 14 is connected. In other words, the annular flow path 56 constitutes a part of the secondary flow path 14. When the pump 60 is housed in the housing chamber 53, the suction port 62c of the pump 60 needs to be connected to the intermediate portion 14a. By having the annular flow path 56, when the pump 60 is housed in the housing chamber 53, the alignment required to connect the suction port 62c of the pump 60 to the intermediate portion 14a is no longer needed. Therefore, by having the annular flow path 56, the assembly of the brake hydraulic control device 50 becomes easier. Furthermore, by having the annular flow path 56, a part of the secondary flow path 14 is also machined when machining the housing chamber 53 on the base 51. Therefore, the machining cost of the base 51, i.e., the manufacturing cost of the brake hydraulic control device 50, can also be reduced. In addition, by having the annular flow path 56, the space on the outer periphery of the pump 60 can be effectively utilized as the secondary flow path 14, so the base 51, i.e., the brake hydraulic control device 50, can also be miniaturized.

[0058] As described above, the ejection chamber 54 formed on the outer peripheral surface of the pump 60 is connected to the first ejection flow path 140a, which forms part of the ejection flow path 140. The receiving chamber 58, which houses the pulsation reduction section 80, is a bottomed hole formed on the outer wall of the base 51. The ejection chamber 54 is connected to the inflow opening 91b of the pulsation reduction section 80 via the first ejection flow path 140a. In the figure, the brake fluid is configured to flow laterally relative to the axis of the receiving chamber 58 of the pulsation reduction section 80. Furthermore, the outflow opening 91c located at the bottom of the receiving chamber 58 is connected to the second ejection flow path 140b. The second ejection flow path 140b is connected to the base 51 via an internal flow path (not shown). Figure 1 The middle part 13b of the main path 13 is connected.

[0059] like Figure 2 As shown, when the pump 60 and the pulsation reduction section 80 are mounted on the base 51, if the pump 60 is driven, the brake fluid flows as follows.

[0060] If the drive shaft 57 is rotated by a drive source not shown, the eccentric portion 57a ​​formed on the drive shaft 57 moves closer to the piston 62, and the piston 62 is pushed towards the cylinder 61 against the force of the spring 67. Therefore, the pressure in the pump chamber 63 increases, the ball valve 64a disengages from the valve seat 64b, and the ejection valve 64 opens. As a result, the brake fluid in the pump chamber 63 is ejected from the ejection port 65b into the ejection chamber 54 through the through hole 61c and the bottomed hole 65a of the cover 65.

[0061] If the drive shaft 57 rotates further, the eccentric portion 57a ​​formed on the drive shaft 57 begins to rotate away from the piston 62. Due to the force of the spring 67, the piston 62 moves away from the cylinder 61. Therefore, the pressure in the pump chamber 63 decreases, the ball valve 64a sits on the valve seat 64b, the ejection valve 64 closes, and the intake valve (not shown), which freely closes the opening of the bottomed hole 62b of the piston 62, opens. Thus, the brake fluid in the annular flow path 56 flows into the pump chamber 63 through the filter 70, the intake port 62c, and the bottomed hole 62b.

[0062] If the drive shaft 57 rotates further, the eccentric portion 57a ​​formed on the drive shaft 57 moves closer to the piston 62, and the piston 62 is pushed towards the cylinder 61 as described above. Brake fluid in the pump chamber 63 is then ejected from the nozzle 65b into the ejection chamber 54. Thus, the piston 62 reciprocates axially in the cylinder 61, selectively opening and closing the intake valve and ejection valve 64 (not shown), thereby increasing the hydraulic pressure and ejecting the pressurized brake fluid from the nozzle 65b into the ejection chamber 54. Therefore, the brake fluid pressurized by the pump 60 pulsates. The brake fluid accompanying this pulsation flows into the pulsation reduction section 80 via the first ejection flow path 140a.

[0063] [Regarding the pulsation reduction device]

[0064] based on Figures 3 to 6 The pulsation reduction device according to this embodiment will be described. Furthermore, the structure of the pulsation reduction device described later uses an example of application of the pulsation reduction section 80, but this structure can also be applied to both the damping unit 37 and the pulsation reduction section 80, or only to one of the damping unit 37 and the pulsation reduction section 80. In this embodiment, the brake hydraulic circuit 2 is structured to include both the damping unit 37 and the pulsation reduction section 80 as a pulsation reduction device, but the brake hydraulic circuit 2 can also be structured to include only the pulsation reduction section 80 as a pulsation reduction device. Hereinafter, the damping unit 37 and the pulsation reduction section 80 will be referred to together as the pulsation reduction device.

[0065] like Figure 3As shown, a receiving chamber 58 is provided in the base 51 of the brake hydraulic control device 50, formed by a cylindrical perforation extending along the axis Ax1, which houses the pulsation reduction portion 80. The receiving chamber 58 includes: a large-diameter portion 58a, formed on the outer periphery of the base 51; a medium-diameter portion 58b, smaller than the large-diameter portion 58a, formed on the inner side of the base 51 closer to the large-diameter portion 58a; and a small-diameter portion 58c, smaller than the medium-diameter portion 58b, formed on the inner side of the base 51 closer to the medium-diameter portion 58b. These large-diameter portions 58a, medium-diameter portions 58b, and small-diameter portions 58c are arranged with the axis Ax1 as a common central axis.

[0066] Furthermore, an inflow opening 91b is provided on the side of the intermediate diameter portion 58b, into which brake fluid F1, compressed by the aforementioned pump 60 and ejected from the nozzle 65b, flows. Additionally, an outflow opening 91c is provided on the bottom surface 58d of the minor diameter portion 58c, communicating with the main flow path 13 and allowing brake fluid F2 to flow from the pulsation reduction portion 80 into the main flow path 13. Furthermore, the opening 58e of the continuously extending receiving chamber 58 to the outer peripheral surface of the base 51 is blocked by a blocking member 81.

[0067] Inside the intermediate diameter portion 58b, a partition member 85 is embedded along the inner circumferential surface of the intermediate diameter portion 58b on the side closer to the small diameter portion 58c than the inflow opening 91b. The partition member 85 is formed in the shape of a disk with an outer diameter approximately equal to the inner diameter of the intermediate diameter portion 58b. This creates a first chamber A, defined by the inner circumferential surface of the intermediate diameter portion 58b, the stepped surface connecting the intermediate diameter portion 58b to the large diameter portion 58a, the inner circumferential surface of the large diameter portion 58a, one end face of the blocking member 81, and one end face of the partition member 85. An inflow opening 91b communicating with the nozzle 65b of the pump 60 is provided on the inner circumferential surface of the first chamber A, and the brake hydraulic pressure, raised by the pump 60, is input to the first chamber A. Furthermore, a second chamber B is formed, defined by the inner circumferential surface and bottom surface of the small diameter portion 58c and one end face of the partition member 85. On the inner circumferential surface of the second chamber B, there is an outflow opening 91c that is connected to the main flow path 13 of the brake hydraulic circuit 2.

[0068] Inside the large-diameter portion 58a are arranged: a first movable body 83, which is formed into a disk shape with an outer diameter approximately equal to the inner diameter of the large-diameter portion 58a, and moves in the direction of axis Ax1; a sealing member 84, which seals the outer peripheral surface of the first movable body 83 with the inner peripheral surface of the large-diameter portion 58a; and a first force-applying member 82, which applies force to the first movable body 83 toward the intermediate-diameter portion 58b. Furthermore, the first movable body 83 has the sealing member 84 disposed on its outer peripheral surface, and slides along the inner peripheral surface of the large-diameter portion 58a in the direction of axis Ax1 while clamping the sealing member 84. As the raw material for the sealing member 84, PTFE can be used, for example, to make the sliding smooth.

[0069] Furthermore, the first chamber A is sealed by the sealing member 84 through the outer peripheral surface of the first moving body 83 and the inner peripheral surface of the large-diameter portion 58a. The first moving body 83 divides the first chamber A into two regions: a first region A1 defined by the inner peripheral surface of the middle-diameter portion 58b, one end face of the separating member 85, and one end face of the first moving body 83; and a second region A2 defined by the inner peripheral surface of the large-diameter portion 58a, one end face of the first moving body 83, and one end face of the blocking member 81. As the first moving body 83 moves towards the blocking member 81, the volume of the first region A1 is increased and the volume of the second region A2 is decreased. Conversely, as the first moving body 83 moves towards the separating member 85, the volume of the first region A1 is decreased and the volume of the second region A2 is increased (see reference). Figure 4 ).

[0070] By means of the brake hydraulic fluid input from the inlet 91b, the first moving body 83 moves against the force of the first force-applying member 82. In the first chamber A, a portion of the energy of the brake hydraulic fluid is consumed by the first force-applying member 82. Therefore, the rate of change and amplitude of change of the brake hydraulic fluid in the first chamber A can be reduced compared to the rate of change and amplitude of change of the brake hydraulic fluid input to the first chamber A, thereby reducing the pulsation of the brake hydraulic fluid output from the pulsation reduction device.

[0071] like Figure 3 As shown, the partition member 85 has, for example, two connecting holes 85a that connect the middle diameter portion 58b side to the small diameter portion 58c side. On the small diameter portion 58c side of each connecting hole 85a, a first valve seat 85b is formed, which is seated on the first valve body 86 corresponding to each connecting hole 85a. By these partition members 85, the first valve seat 85b, the first valve body 86, and the force members (second force member 89 and third force member 90) that apply force to the first valve body 86 toward the first valve seat 85b side as described later, a connecting portion 80a connecting the first chamber A and the second chamber B is formed.

[0072] Furthermore, when at least one first valve body 86 is in a connection position not seated in the corresponding first valve seat 85b, the middle diameter portion 58b side and the small diameter portion 58c side of the connecting hole 85a, i.e., the first chamber A side and the second chamber B side, are connected, and brake hydraulic pressure is transmitted between the first chamber A and the second chamber B (see reference). Figure 4 On the other hand, when all the first valve bodies 86 are in the non-connected position seated on the corresponding first valve seat 85b, all the connecting holes 85a are closed by the first valve bodies 86, resulting in a state where the first chamber A side and the second chamber B side are not connected, and brake hydraulic pressure is not transmitted between the first chamber A and the second chamber B (see reference). Figure 3 ).

[0073] In addition, the pulsation reduction section 80 of this embodiment has a structure in which the separating member 85 has two first valve seats 85b and two first valve bodies 86 corresponding to the first valve seats 85b. However, the pulsation reduction section may also have a structure in which each has one first valve seat and one first valve body, or it may have a structure in which each has three or more first valve seats and one first valve bodies.

[0074] Inside the small-diameter portion 58c, there are: the aforementioned first valve body 86; a second moving body 87, which is formed into a disk shape with an outer diameter smaller than the inner diameter of the small-diameter portion 58c and moves in the direction of axis Ax1; a second force-applying member 89, which applies force to the second moving body 87 toward the separating member 85; a second valve body 88, which is seated on the second valve seat 87e provided on the second moving body 87; and a third force-applying member 90, which applies force to the second valve body 88 toward the second valve seat 87e.

[0075] The second movable body 87 includes: a main body 87a, which is formed in a disc shape; a groove-shaped groove 87b formed on one end face of the main body 87a to position the first valve body 86; a protrusion 87c formed to protrude toward the end face opposite to the groove 87b to position the second force-applying member 89; and a through hole 87d that extends from one end face of the main body 87a to the other end face. Furthermore, a second valve seat 87e is formed at the end of the through hole 87d on the protrusion 87c side, on which the second valve body 88 sits.

[0076] By disposing the first valve body 86 inside the groove 87b of the second movable body 87, the positional relationship between the first valve body 86 and the second movable body 87 is determined, and the first valve body 86 can be seated on the first valve seat 86e.

[0077] Furthermore, the second force-applying member 89 is formed in a ring shape. By being arranged such that the inner peripheral surface of the second force-applying member 89 abuts against the outer peripheral surface of the protrusion 87c of the second moving body 87, the positional relationship between the second force-applying member 89 and the second moving body 87 is determined. The second force-applying member 89 applies force to the second moving body 87 toward the separating member 85 side, and the second force-applying member 89 applies force to the first valve body 86 toward the first valve seat 85b side via the second moving body 87.

[0078] Furthermore, the second valve body 88 is seated on the second valve seat 87e by the force applied by the third force-applying member 90. The third force-applying member 90 applies force to the second valve body 88 towards the second valve seat 87e, and also applies force to the first valve body 86 towards the first valve seat 85b via the second valve body 88 and the second moving body 87. That is, the second force-applying member 89 and the third force-applying member 90 apply force to the first valve body 86 and the second moving body 87 towards the first valve seat 85b.

[0079] Furthermore, the second force-applying component 89 is formed of a resin material such as elastomeric rubber, as described later. When the second force-applying component 89 is in close contact with the positioning part of the second moving body 87 and the second valve seat 87e of the second moving body 87 is seated by the second valve body 88, the second chamber B is divided into two regions B1 and B2 by the second moving body 87, the second force-applying component 89, and the second valve body 88. A third region B1 is formed by the inner peripheral surface and bottom surface of the small diameter portion 58c, the outer peripheral surface of the second force-applying component 89, the outer peripheral surface of the second moving body, and the outer peripheral surface of the second valve body 88. A fourth region B2 is formed by the bottom surface of the small diameter portion 58c, the inner peripheral surface of the second force-applying component 89, the outer peripheral surface of the second moving body 87, and the outer peripheral surface of the second valve body 88. By moving the second moving body 87 toward the bottom surface of the small-diameter portion 58c, the volume of the third region B1 is expanded and the volume of the fourth region B2 is reduced. On the other hand, by moving the second moving body 87 toward the separating member 85, the volume of the third region B1 is reduced and the volume of the fourth region B2 is expanded (see reference). Figure 4 ).

[0080] Furthermore, when the brake hydraulic pressure on the third region B1 side is lower than that on the fourth region B2 side, the second valve body 88 remains seated with force applied to the second valve seat 87e by the third force-applying component 90, thus the third region B1 side and the fourth region B2 side are not connected, and brake hydraulic pressure is not transmitted between the third region B1 and the fourth region B2 (see reference). Figure 3 , Figure 4 On the other hand, when the brake hydraulic pressure on the third region B1 side is higher than that on the fourth region B2 side, the second valve body 88 disengages from the second valve seat 87e, resulting in a connection between the third region B1 side and the fourth region B2 side. Brake hydraulic pressure is then transferred between the third region B1 and the fourth region B2 (see reference). Figure 5 ).

[0081] The first force-applying component 82 and the second force-applying component 89 are as follows: Figure 6As shown, the elastic body, which exhibits different hysteresis characteristics R1 during the loading process (displacement changing from 0 to s1) and the unloading process (displacement changing from s1 to 0) when the displacement s is the same, is formed into a ring-shaped component. For example, elastic springs made of materials such as ethylene propylene diene monomer (EPDM) rubber or silicone can be used as materials for the first force-applying component 82 and the second force-applying component 89. Furthermore, the first force-applying component 82 and the second force-applying component 89 can be formed from one material or multiple materials. For example, EPDM with a relatively low resilience can be sandwiched between silicone with a relatively high resilience. Depending on the combination of materials and the shape, the resilience of the force-applying component can be adjusted to match the inherent pulsation frequency generated by the performance of the pump 60 originating from the braking hydraulic pressure.

[0082] The third force-applying component 90 is as follows Figure 6 The elastic body shown has a characteristic R2 that is larger in the unloading process (the process of displacement changing from s2 to 0) when the displacement s is the same as that of the second force-applying component 89, than in the unloading process (the process of displacement changing from s1 to 0) or the loading process (the process of displacement changing from 0 to s1) of the second force-applying component 89 when the displacement s is the same. As the third force-applying component 90, a metal spring can be used, for example. Furthermore, the third force-applying component 90 can be formed from one material or multiple materials. Depending on the combination of materials and its shape, the rebound coefficient of this force-applying component can be adjusted to match the inherent pulsation frequency generated by the performance of the pump 60 caused by the braking hydraulic pressure.

[0083] Next, based on Figures 3 to 5 The operation of the pulsation reduction device in this embodiment will be explained.

[0084] like Figure 3 As shown, when pump 60 is in a non-driven state without being driven, or when the brake hydraulic output pressure on the ejection side of pump 60 has not exceeded a predetermined first pressure value P1 immediately after pump 60 is started, the first valve body 86 is seated in the first valve seat 85b, and the second valve body 88 is seated in the second valve seat 87e. In this state, the brake hydraulic pressure on the ejection side of pump 60 is supplied only to the first region A1 of the first chamber A.

[0085] Then, as Figure 4As shown, from the moment the pump 60 is started until the brake hydraulic pressure on the ejection side of the pump 60 rises to a predetermined first pressure value P1, the brake hydraulic pressure acts on the first moving body 83 as the brake hydraulic pressure on the ejection side of the pump 60 rises. The first moving body 83 moves against the force exerted by the first force-applying member 82. At this time, because the first moving body 83 moves against the force exerted by the first force-applying member 82, a portion of the energy of the brake hydraulic pressure is consumed. Furthermore, along with the movement of the first moving body 83, a portion of the energy of the brake hydraulic pressure is also consumed by the sliding resistance of the sealing member 84 disposed on the outer peripheral surface of the first moving body 83. Due to this energy consumption, the variation in brake hydraulic pressure within the first region A1 is reduced compared to the variation in brake hydraulic pressure on the ejection side of the pump 60.

[0086] Then, when the brake hydraulic pressure on the ejection side of pump 60 exceeds the first pressure value P1 due to the driving of pump 60, the first valve body 86 and the second moving body 87 move against the forces of the second force-applying member 89 and the third force-applying member 90, and the first valve body 86 disengages from the first valve seat 85b, connecting the first chamber A and the second chamber. At this time, since the first valve body 86 and the second moving body 87 move against the forces exerted by the second force-applying member 89 and the third force-applying member 90, a portion of the energy of the brake hydraulic pressure is consumed by these force-applying members, and the variation in brake hydraulic pressure in the third region B1 of the second chamber B is reduced compared to the variation in brake hydraulic pressure in the first region A1 of the first chamber A.

[0087] Then, as Figure 5 As shown, with the actuation of pump 60, the brake hydraulic pressure on the ejection side of pump 60 is further increased. When the brake hydraulic pressure in the third region B1 exceeds a second pressure value P2 that is higher than a predetermined first pressure value P1, the second valve body 88 moves against the force of the third force-applying member 90. The second valve body 88 disengages from the second valve seat 87e, and the third region B1 and the fourth region B2 of the second chamber B are connected. Then, the brake hydraulic pressure increased with the actuation of pump 60 is output from the pulsation reduction device to the brake hydraulic circuit 2. At this time, since the second valve body 88 moves against the force exerted by the third force-applying member 90, a portion of the energy of the brake hydraulic pressure is consumed by the third force-applying member 90, and the fluctuation of the brake hydraulic pressure in the fourth region B2 of the second chamber B is reduced compared to the fluctuation of the brake hydraulic pressure in the third region B1 of the second chamber B. Therefore, within the pulsation reduction device, the fluctuation of the brake hydraulic fluid is reduced by the forces exerted by the first force-applying component 82, the second force-applying component 89, and the third force-applying component 90, as well as the sliding resistance from the sealing component 84. As a result, the pulsation of the brake hydraulic fluid output from the pulsation reduction device to the brake hydraulic fluid circuit 2 is reduced compared to the pulsation of the brake hydraulic fluid on the ejection side of the pump 60.

[0088] If the brake hydraulic pressure in the third region B1 exceeds the second pressure value P2 and then falls below the second pressure value P2 again, the second valve body 88 moves by means of the force of the third force-applying component 90 and sits on the second valve seat 87e. The second valve body 88 and the second valve seat 87e act as a check valve, and the decrease in brake hydraulic pressure in the fourth region B2 is reduced.

[0089] Then, as the brake hydraulic pressure in region B1 further decreases, the second moving body 87 and the first valve body 86 move towards the first valve seat 85b by means of the force of the third force-applying component 90. At this time, the second force-applying component 89, due to the hysteresis in the restoring force during the loading and unloading processes as described above, contracts due to the thrust from the first valve body 86, and needs a predetermined period of time to return to the displacement where the force can be applied to the second moving body 87 and the first valve body 86. Then, as the brake hydraulic pressure in region B1 begins to rise before the force from the second force-applying component 89 begins to act on the second moving body 87 and the first valve body 86, the second moving body 87 and the first valve body 86 move only against the force from the third force-applying component 90, and in a shorter period than when the force from the second force-applying component 89 is applied, the brake hydraulic pressure in region B1 can exceed the second pressure value P2. This reduces the drop in brake hydraulic pressure within region B2 of zone 4.

[0090] The pulsation reduction device of this embodiment, as described above, sequentially changes state according to the fluctuation of the brake hydraulic pressure accompanying the drive of the pump 60: the first valve body 86 is seated on the first valve seat 85b, the first valve body 86 is removed from the first valve seat 85b, the second valve body 88 is seated on the second valve seat 87e, and the second valve body 88 is removed from the second valve seat 87e. This reduces the pulsation of the brake hydraulic pressure accompanying the drive of the pump 60. As a result, noise caused by the pulsation accompanying the drive of the pump 60 can be reduced.

[0091] [Regarding the function and effect of the pulsation reduction device]

[0092] The vehicle's braking system 1 includes a brake hydraulic circuit 2 that supplies brake hydraulic fluid from the master cylinder 11 to the wheel cylinders 12, a pump 60 that raises the brake hydraulic fluid in the brake hydraulic circuit 2, and a brake hydraulic control device 50 that controls the brake hydraulic fluid. In such a braking system 1, there is a possibility that pulsations may occur in the brake hydraulic fluid due to the driving of the pump 60. These pulsations may be propagated through the brake hydraulic circuit 2 to the wheel cylinders 12 or to the engine compartment of the vehicle equipped with the braking system 1 containing the pump 60. There is a concern that this may generate noise that could cause unpleasantness or discomfort to the vehicle's driver, passengers, or people outside the vehicle.

[0093] In contrast, the brake hydraulic control device 50 of the brake system 1 in this embodiment includes a pulsation reduction device for reducing the pulsation of brake hydraulic fluid in the brake hydraulic circuit 2. The pulsation reduction device has the following structure: a first chamber A, into which brake hydraulic fluid is input from the brake hydraulic circuit 2; a second chamber B, into which brake hydraulic fluid is output to the brake hydraulic circuit 2; and a connecting portion 80a connecting the first chamber A and the second chamber B; the connecting portion 80a includes: a first valve body 86, which can be moved to a non-connected position where it is seated on a first valve seat 85b without connecting the first chamber A and the second chamber B, and a connected position where it is removed from the first valve seat 85b and connects the first chamber A and the second chamber B; and a force-applying member that applies force to the first valve body 86 toward the first valve seat 85b; the force-applying member includes a second force-applying member 89 and a force-applying member 89 connected to the first valve body 86. The force-applying component 89 is different from the third force-applying component 90; the second force-applying component 89 has a hysteresis characteristic that the restoring force p in the loading process and the restoring force p in the unloading process are different magnitudes when the displacement s is the same in the loading process (the process of displacement changing from 0 to s1) and the unloading process (the process of displacement changing from s1 to 0); the third force-applying component 90 has a characteristic that the restoring force p in the unloading process (the process of displacement changing from s2 to 0) when the displacement s is the same as that of the second force-applying component 89 is larger than the restoring force p in the unloading process (the process of displacement changing from s1 to 0) of the second force-applying component 89 when the displacement s is the same.

[0094] According to this structure, the connection 80a between the first chamber A and the second chamber B includes a first valve body 86, and a second force-applying member 89 and a third force-applying member 90 that apply force to the first valve body 86 toward the first valve seat 85b. The second force-applying member 89 has a hysteresis characteristic that the recovery force p during the load process and the recovery force p during the unload process are different magnitudes when the displacement s is the same during the load process and the unload process. The third force-applying member 90 has a characteristic that the recovery force p during the unload process when the displacement s is the same as that of the second force-applying member 89 is larger than the recovery force p during the unload process of the second force-applying member 89 when the displacement s is the same. Therefore, when the input brake hydraulic pressure from the brake hydraulic circuit 2 to the first chamber A exceeds a predetermined first pressure value P1, and the brake hydraulic pressure on the first chamber A side is higher than the brake hydraulic pressure on the second chamber B side, the first valve body 86 is subjected to force by the second force-applying member 89 and the third force-applying member 90. Therefore, as the brake hydraulic fluid input to chamber A rises with the drive of pump 60, the first valve body 86 moves against the two forces exerted by the second force-applying component 89 and the third force-applying component 90. That is, in this process, a portion of the energy of the brake hydraulic fluid input to chamber A is consumed by the two force-applying components and output to chamber B, so the rate of change of the brake hydraulic fluid rising on the side of chamber B can be reduced compared to the rate of change of the brake hydraulic fluid input on the side of chamber A.

[0095] On the other hand, since the second force-applying component 89 has a hysteresis characteristic of restoring force p, and the third force-applying component 90 has a greater restoring force p during the unloading process than the second force-applying component 89 when the displacement s is the same, the second force-applying component 89 returns to the unloaded state at a slower speed than the third force-applying component 90. Therefore, when the input brake hydraulic pressure from the brake hydraulic circuit 2 to the first chamber A exceeds the second pressure value P2, and the brake hydraulic pressure on the first chamber A side becomes lower than the brake hydraulic pressure on the second chamber B side, for a predetermined period of time, the first valve body 86 is only force-applying by the third force-applying component 90. During the process of the brake hydraulic pressure in the first chamber A decreasing, the first valve body 86 is force-applying by the third force-applying component and moves towards the first valve seat 85b. The brake hydraulic pressure in the first chamber A decreases to a predetermined second pressure value P2, which is lower than the first pressure value P1, and thus the first valve body 86 sits on the first valve seat 85b. On the other hand, if the brake hydraulic pressure in chamber A drops to the second pressure value P2 and then begins to rise again, the first valve body 86 moves only against the force of the third force-applying component 90. A portion of the energy of the brake hydraulic pressure input to chamber A is not consumed by the second force-applying component 89, and the corresponding energy is used to increase the brake hydraulic pressure in chamber B. That is, in this case, the rate of decrease in brake hydraulic pressure on the chamber B side can be reduced. Therefore, by means of a pulsation reduction device with the structure described above, the rate and magnitude of change of brake hydraulic pressure in chamber B output to the brake hydraulic circuit 2 can be reduced, and the pulsation of brake hydraulic pressure within the vehicle's brake hydraulic circuit 2 can be reduced.

[0096] In the pulsation reduction device of this embodiment, the second force-applying member 89 is an elastic spring, for example, formed of ethylene propylene diene monomer (EPDM) rubber, silicone, or similar materials. With this structure, the second force-applying member 89 possesses a hysteresis characteristic where the restoring force during the loading process and the restoring force during the unloading process are of different magnitudes when the displacement is the same during the loading and unloading processes. Therefore, the pulsation of the brake hydraulic pressure within the vehicle's brake hydraulic circuit 2 can be reduced by means of the pulsation reduction device.

[0097] Furthermore, in the pulsation reduction device of this embodiment, the third force-applying member 90 is a metal spring. With this structure, the third force-applying member 90 has the characteristic that its restoring force p during the unloading process when it has the same displacement s as the second force-applying member 89 is greater than the restoring force p during the unloading process of the second force-applying member 89 when it has the same displacement s. By means of the pulsation reduction device, the pulsation of the brake hydraulic pressure within the vehicle's brake hydraulic circuit 2 can be reduced.

[0098] Furthermore, the pulsation reduction device of this embodiment has the following structure: in the first chamber A upstream of the connecting portion 80a, there is a first moving body 83 that moves in the direction of axis Ax1 and a first force-applying member 82 that applies force to the first moving body 83; the first moving body 83 divides the first chamber A into two regions, and the volume of the first region A1, which receives brake hydraulic fluid from the brake hydraulic circuit 2, changes as the first moving body 83 moves. With this structure, in the first region A1 upstream of the connecting portion 80a, pre-processing to reduce the fluctuation of brake hydraulic fluid input from the brake hydraulic circuit 2 can be performed, and the pulsation of brake hydraulic fluid at the connecting portion 80a downstream of the first region A1 can be further reduced.

[0099] Furthermore, the pulsation reduction device of this embodiment has the following structure: in the first chamber A upstream of the connecting part 80a, there is a first moving body 83 that moves in the direction of axis Ax1 and a first force-applying member 82 that applies force to the first moving body 83; the first force-applying member 82 is an elastic spring, for example, formed of ethylene propylene diene monomer (EPDM) rubber, silicone or the like. According to this structure, the first force-applying member 82 can have a hysteresis characteristic that the recovery force during the loading process and the recovery force during the unloading process are different magnitudes when the displacement is the same during the loading process and the unloading process, and the pulsation of the brake hydraulic pressure in the brake hydraulic circuit 2 of the vehicle can be reduced by means of the pulsation reduction device.

[0100] The above describes examples of embodiments of the present invention, but the present invention is not limited to these examples. Any changes or additions that do not depart from the spirit of the present invention are naturally included in the present invention.

[0101] Explanation of reference numerals in the attached figures

[0102] 1. Braking system

[0103] 2. Brake hydraulic circuit

[0104] 50 Brake hydraulic control device

[0105] 37 Damping Units

[0106] 50 Brake hydraulic control device

[0107] 60 pumps

[0108] 80 Pulsation Reduction Section

[0109] 81 Blocking components

[0110] 80a Connection Part

[0111] 82 First force-applying component

[0112] 83 The first moving body

[0113] 84 Sealing components

[0114] 85. Separating components

[0115] 86 Valve Body No. 1

[0116] 87 The 2nd moving body

[0117] 88. Valve body No. 2

[0118] 89 Second force-applying component

[0119] 90 Third force-applying component

Claims

1. A pulsation reduction device (37, 80) is installed in the braking system of a vehicle having a brake hydraulic circuit (2) supplying brake hydraulic fluid to a wheel cylinder (12) and a pump (60) for increasing the brake hydraulic fluid, characterized in that, have: Chamber 1 (A) is supplied with brake hydraulic fluid from the aforementioned brake hydraulic circuit (2); Chamber 2 (B) outputs brake hydraulic pressure to the aforementioned brake hydraulic circuit (2); as well as The connecting part (80a) connects the aforementioned first chamber (A) and the aforementioned second chamber (B); The aforementioned connecting part (80a) includes: The valve body (86) is moved to a non-connected position where it is seated on the valve seat (85b) without connecting the first chamber (A) and the second chamber (B), and to a connected position where it is removed from the valve seat (85b) and connects the first chamber (A) and the second chamber (B); and The force-applying components (89, 90) apply force to the valve body (86) towards the valve seat (85b); The aforementioned force-applying components (89, 90) include a first force-applying component (89) and a second force-applying component (90) that is different from the first force-applying component (89); The aforementioned first force-applying component (89) has a hysteresis characteristic that the restoring force during the loading process and the restoring force during the unloading process are different magnitudes when the displacement is the same during the loading process and the unloading process. The aforementioned second force-applying component (90) has the characteristic that the restoring force during the unloading process when it is in the same displacement as the aforementioned first force-applying component (89) is greater than the restoring force during the unloading process of the aforementioned first force-applying component (89) when it is in the same displacement.

2. The pulsation reduction device as described in claim 1, characterized in that, The aforementioned first force-applying component (89) is formed of an elastic spring.

3. The pulsation reduction device as described in claim 1 or 2, characterized in that, The aforementioned second force-applying component (90) is formed of a metal spring.

4. The pulsation reduction device according to any one of claims 1 to 3, characterized in that, have: The moving body (83) divides the aforementioned first chamber (A) into a first region (A1) including an inlet (91b) into which brake hydraulic fluid is input from the aforementioned brake hydraulic circuit (2) and a second region (A2) excluding the inlet (91b), and moves within the first chamber (A); as well as The third force-applying component (82) applies force to the moving body (83).

5. The pulsation reduction device as described in claim 4, characterized in that, The aforementioned third force-applying component (82) is formed of an elastic spring.

6. A vehicle brake hydraulic control device (50), characterized in that, The device comprising any one of claims 1 to 5.

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