JPH0632246U - Brake fluid pressure control device - Google Patents

Abstract

(57) [Abstract] [Purpose] To prevent the function of the throttle of the brake fluid passage from being impaired by the entry of foreign matter in the brake fluid. [Structure] First and second spools 11 and 21 are vertically movably fitted in a hole 1A of a body 1, and a throttle member 9 is provided at an upper end portion of the second spool 21. When the lower end and the throttle member 9 are pressed against _{each other} at the lower position P ₁ , the throttle groove 9B of the throttle member 9 forms a throttle passage having a predetermined cross-sectional area.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a brake fluid pressure control device, and more particularly, to a brake fluid pressure control device incorporated in an anti-lock brake system (ABS) of a vehicle.

[0002]

[Prior art]

 Conventionally, as this type of hydraulic pressure control device, for example, one described in Japanese Utility Model Laid-Open No. 3-52269 is known.

In such a hydraulic pressure control device, a return passage for returning brake fluid from a reservoir to a master cylinder is merged with a communication passage between a master cylinder and a wheel cylinder, and a throttle amount is fixed at the merged portion. Further, there is provided a narrowed portion, that is, a narrowed portion in which the cross section of the flow channel is fixed to a predetermined size. The throttle prevents the pulse pressure in the return passage from being transmitted to the master cylinder, that is, the pulse pressure of the brake fluid generated by the pump that pumps brake fluid from the reservoir to the master cylinder. It is configured to do.

[0004]

[Problems to be solved by the device]

 However, in the above-mentioned conventional hydraulic pressure control device, since the flow passage cross section of the throttle portion is always small, foreign matter in the brake fluid enters the throttle portion to sufficiently reduce the pulse pressure in the brake fluid. However, there was a risk that noise and kickback to the brake pedal would occur due to the pulse pressure.

An object of the present invention is to provide a brake fluid pressure control device that can prevent the function of the throttle portion of the brake fluid passage from being impaired due to the entry of foreign matter in the brake fluid.

[0006]

[Means for Solving the Problems] A brake fluid pressure control device of the present invention is a master cylinder that outputs a brake fluid pressure according to the amount of depression of a brake pedal, and a wheel control device that responds to an input brake fluid pressure. A brake fluid pressure control device connected in a communication passage with a wheel cylinder that generates power, wherein the brake fluid pressure on the master cylinder side moves from a first position to a second position when the brake fluid pressure is a predetermined value or more. From the first position, when the brake fluid pressure on the wheel cylinder side is higher than the brake fluid pressure on the master cylinder side by a predetermined amount or more, facing the first mobile body and the first mobile body. A second moving body that moves to the second position, and a first moving body that communicates the master cylinder side and the wheel cylinder side when the second moving body is at the first position. A passage, a second communication passage that opens to one side of the facing portion of the first and second moving bodies and communicates the master cylinder side and the wheel cylinder side, and the first and second transfer passages. A throttle portion that is provided on the other side of the facing portion of the moving body and narrows down the opening portion of the second communication passage when the first and second moving bodies are in pressure contact with each other, and is interposed in the second communication passage. And a one-way valve that allows the flow of the brake fluid from the wheel cylinder side to the master cylinder side and blocks the flow of the brake fluid in the opposite direction.

[0007]

[Action]

 The brake fluid pressure control device of the present invention narrows or opens the opening portion of the communication passage between both cylinders by the first and second moving bodies that move according to the pressure difference between the master cylinder side and the wheel cylinder side. This prevents the function of the throttle of the brake fluid passage from being impaired by the entry of foreign matter in the brake fluid, and fully exerts the function of the throttle.

[0008]

【Example】

 An embodiment of the present invention will be described below with reference to the drawings.

In FIG. 1, reference numeral 1 denotes a body provided with first and second ports 1A and 1B, and the first port 1A is a master cylinder that outputs a brake fluid pressure according to a depression amount of a brake pedal. The second port 1B is connected to a wheel cylinder (not shown) via a control unit (not shown) of the ABS. The wheel cylinder generates a braking force for the wheels according to the input brake fluid pressure. The control unit includes a brake fluid passage that connects and disconnects the second port 1B and the wheel cylinder via a check valve or a solenoid valve, and a brake fluid that is pumped from the reservoir by a pump. The return passage leading to the port 1B of the is constructed.

The body 1 is provided with a hole 1C penetrating in the vertical direction and communicating with the first and second ports 1A and 1B, and the upper end of the hole 1C is liquid-tight by the screw 2. The plug 3 and the screw 4 close the lower end thereof in a liquid-tight manner. Further, in the hole 1C, first and second spools (first and second moving bodies) 11 and 21 are arranged vertically and are fitted in a vertically slidable manner. . The first spool 11 is urged downward by the spring 5, while the second spool 21 is urged upward by the spring 6, and the urging force of the former spring 5 is greater than that of the latter spring 5. It is set larger than the spring 6. Therefore, normally, as shown in FIG. 1, the first spool 11 is in the downward movement limit position, and the lower end thereof and the upper end portion of the second spool 21 are at a predetermined lower position (first position) P. Pressed on ₁ .

The second spool 21 is formed with a first through hole 21A penetrating in the vertical direction and a second through hole 21B penetrating radially outward from an intermediate portion of the through hole 21A. The outer opening of the second through hole 21B faces the annular groove 1D on the body 1 side regardless of the vertical movement of the second spool 21. The annular groove 1D communicates with the second port 1B. Therefore, the first and second through holes 21A and 21B connect the wheel cylinder and the master cylinder to each other and have a communication passage (second communication passage) that has an opening at a position facing the first spool 11. ) Will be formed. Further, a cutout portion 21C is formed on the outer peripheral surface on the upper side of the spool 21, and the cutout portion 21C is provided with an upper chamber R ₁ which will be described later when the upper end portion of the spool 21 is at the lower position P _1. The upper chamber R ₁ and the annular groove 1D are not communicated with each other when the upper end portion of the spool 21 is at an upper position (second position) P ₂ described later. Therefore, the cutout portion 21C forms a communication passage (first communication passage) that communicates between the wheel cylinder and the master cylinder when the spool 21 is at the lower position P ₁ .

A diaphragm member 7 for narrowing down the inner diameter of the first through hole 21A is fitted to the lower end portion of the first through hole 21A, and the upper end portion of the through hole 21A is unidirectional as shown in FIG. A valve 8 and a throttle member 9 are provided. The one-way valve 8 is provided with a ball 8B, which is urged downward by a spring 8A, as a valve element, allows the brake fluid to flow from the lower side to the upper side in the figure, and allows the brake fluid to flow in the opposite direction. Block. The diaphragm member 9 is formed with a through hole 9A penetrating the central portion thereof in the vertical direction and a diaphragm groove 9B formed on the upper surface of the diaphragm member 9 and extending radially from the upper opening of the through hole 9A. In FIG. 1, 10A and 10B are annular seal members.

Next, the operation will be described.

A liquid chamber (hereinafter, referred to as “upper chamber”) R above the second spool 21 in the hole 1C of the body 1₁ Always communicates with a master cylinder (not shown) through the first port 1A, while the liquid chamber (hereinafter referred to as “lower chamber”) R below the spool 21 is ₂ Is always connected via the throttle member 7, the first and second through holes 21A and 21B, the annular groove 1D, and the second port 1B to the above-mentioned brake fluid passage in the ABS control unit (not shown). It is connected to the passage. Upper chamber R like this₁ And R₂ The internal pressure of the pump changes depending on the operating state of the brake, and "when the brake is not operated", "when the brake is operated normally", and when "ABS" is activated (the pump pumps the brake fluid in the reservoir to the return passage). The hydraulic pressure control device operates in the following manner by the change of their internal pressures at the time of "operation of").

[When the brake is not operated] The internal pressures of the upper chamber R ₁ and the lower chamber R ₂ both become low pressures close to atmospheric pressure, and the first spool 11 moves downward as shown in FIGS. 1 and 2. At the limit position, the lower end thereof and the upper surface of the throttle member 9 of the second spool 21 are in pressure contact with each other at the lower position P ₁ . At this time, the notch 21C of the spool 21 communicates between the upper chamber R ₁ and the annular groove 1D. Therefore, the ports 1A and 1B are in communication with each other.

“During Normal Brake Operation” During normal brake operation in which the ABS does not operate, the pressure in the upper chamber R ₁ rises, and the spool 11 resists the urging force of the spring 5, as shown in FIG. Is pushed up to the upper limit position, and its lower end is located above the upper position P ₂ . On the other hand, the spool 21 is located below as shown in FIG. 3, and allows the flow of the brake fluid from the port 1A side to the port 1B side, which changes according to the brake operation amount, and the flow in the opposite direction. That is, when the former brake fluid flows, the spool 21 is pressed and maintained downward to allow the brake fluid to flow through the notch portion 21C, while the latter brake fluid flows, the notch portion 21C and The flow of the break liquid is allowed through the one-way valve 8. Further, during the latter flow, the pressure increase in the lower chamber R ₂ is delayed by the action of the throttle member 7 and the upward movement of the spool 21 is suppressed, and the through hole 9A and the throttle groove 9B of the throttle member 9 are suppressed. There is no opening in the upper part, and foreign matter in the brake fluid does not get stuck inside them.

Eventually, the ports 1A and 1B are in communication even during this normal brake operation. Further, when the brake operation is released, the state returns to the state of FIGS. 1 and 2 described above.

[At ABS Operation] When ABS is operated and the brake fluid in the reservoir is pumped to the return passage by the pump and introduced into the port 1B, the spool 21 is moved upward as shown in FIG. moving towards the lower end of the stop member 9 and the spool 11 of the upper end portion is pressed at the upper position P ₂ above. Therefore, the notch 21C of the spool 21 does not communicate between the upper chamber R ₁ and the annular groove 1D, and the throttle member 9 is opened by the spool 11 in the through hole 9A as in the case of FIG. The portion is closed and the throttle groove 9B is throttled so as to form a throttle passage having a predetermined cross-sectional area, and the through hole 9A communicates with the upper chamber R ₁ through the throttle passage.

As a result, the brake fluid pumped into the port 1B passes through the one-way valve 8 and is throttled by the throttle groove 9B forming the above-mentioned throttle passage, and then flows into the port 1A, and the master cylinder Returned inside. At this time, the throttle groove 9B causes the pulse pressure in the brake fluid to be transmitted to the master cylinder due to the throttle action, that is, the pulse pressure in the brake fluid generated by the pump that pumps the brake fluid in the reservoir into the return passage. Will be prevented from being transmitted to the master cylinder. When the brake operation is released, the state returns to the state shown in FIGS. 1 and 2 and the ports 1A and 1B are in a communication state in which the brake fluid can smoothly pass.

[0020]

[Effect of device]

 As described above, in the brake fluid pressure control device of the present invention, the first and second moving bodies that move according to the pressure difference between the master cylinder side and the wheel cylinder side cause the communication passage between the two cylinders to move. Since the opening is squeezed and opened, it is possible to prevent the function of the throttle of the brake fluid passage from being impaired by the entry of foreign matter in the brake fluid, and to fully exhibit the function of the throttle. be able to.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view showing an embodiment of the present invention when a brake is not operated.

FIG. 2 is an enlarged sectional view of a II circle portion in FIG.

3 is a vertical cross-sectional view of the brake fluid pressure control device shown in FIG. 1 in a state during normal brake operation.

FIG. 4 is a vertical cross-sectional view of the brake fluid pressure control device shown in FIG. 1 in a state during ABS operation.

[Explanation of symbols]

1 Body 1A 1st port 1B 2nd port 2 Screw 3 Plug 4 Screw 5,6 Spring 7 Throttling member 8 One-way valve 9 Throttling member 9A Through hole 9B Throttling groove 11 1st spool (1st moving body) 21 Second Spool (Second Moving Body) 21A, 21B Through Hole (Second Communication Passage) 21C Notch (First Communication Passage) R ₁ Upper Chamber R ₂ Lower Chamber P ₁ Lower Position (1st Position) P ₂ upper position (second position)

Claims (2)

[Scope of utility model registration request] 1. A brake connected in a communication path between a master cylinder that outputs a brake fluid pressure according to the amount of depression of a brake pedal and a wheel cylinder that generates a braking force for a wheel according to the input brake fluid pressure. A hydraulic pressure control device, comprising: a first moving body that moves from a first position to a second position when the brake hydraulic pressure on the master cylinder side is equal to or higher than a predetermined value; and a first moving body that faces the first moving body. A second moving body that moves from the first position to the second position when the brake fluid pressure on the wheel cylinder side becomes higher than the brake fluid pressure on the master cylinder side by a predetermined amount or more; A first communication passage that connects the master cylinder side and the wheel cylinder side when the second moving body is at the first position; and one of the facing portions of the first and second moving bodies. A second communication passage that opens to the side to connect the master cylinder side and the wheel cylinder side to each other, and the second communication path that is provided on the other side of the facing portion of the first and second moving bodies. A throttle portion that narrows the opening portion of the second communication passage when the moving bodies are pressed against each other, and a flow of brake fluid from the wheel cylinder side to the master cylinder side that is interposed in the second communication passage. A brake fluid pressure control device, comprising: a one-way valve that allows the brake fluid to flow in the opposite direction. 2. A throttle groove extending outward is formed in an opening portion of the second communication passage, and the throttle portion is configured such that when the first moving body and the second moving body are in pressure contact with each other. The brake fluid pressure control device according to claim 1, wherein the opening portion of the second communication passage except the groove is closed.