JPH0568766U - Anti-skid brake device - Google Patents

Abstract

(57) [Summary] [Purpose] To improve the quick braking response during normal braking without compromising anti-skid control performance. [Structure] Flow control valve 20 provided in main brake circuit 1
Is the difference between the hydraulic pressure of the wheel cylinder 4 introduced into the first hydraulic chamber 24 on one side of the piston 22 and the hydraulic pressure of the master cylinder 3 introduced into the second hydraulic chamber 25 on the other side of the piston 22. The piston 22 is moved to the first liquid chamber 24 side by the pressure, so that the flow passage in the second liquid chamber 25 is changed from the open state to the throttled state. The third liquid chamber 26 adjacent to the second liquid chamber 25 communicates with the master cylinder 3 via the orifice 34, and the valve shaft 44 protruding from the valve body 43 of the valve portion 40.
The pressure receiving surface 44 a at the rear end is arranged in the third liquid chamber 26.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a brake fluid recirculation type anti-skiked brake device used in a vehicle such as an automobile.

[0002]

[Prior Art]

 Various brake fluid recirculation type anti-skid brake devices are known, but among them, as disclosed in Japanese Utility Model Laid-Open No. 3870/1993, the main brake fluid is supplied from a master cylinder to a wheel cylinder. In the middle of the brake circuit, open the flow path until the differential pressure between the master cylinder side hydraulic pressure and the wheel cylinder side hydraulic pressure reaches the set value, and when the differential pressure exceeds the set value during anti-skid control, the flow path is opened. It is known that a flow control valve that restricts the hydraulic pressure is provided to obtain a moderate pressure increase characteristic that suppresses the rising gradient of the hydraulic pressure on the wheel cylinder side during anti-skid control, and attempts to control the hydraulic pressure to an appropriate value.

[0003]

[Problems to be solved by the device]

 As described above, the flow control valve operates to throttle the flow path when the differential pressure between the master cylinder side hydraulic pressure and the wheel cylinder side hydraulic pressure exceeds the set value, so when the anti-skid non-actuated pressure increase, that is, Even at the time of sudden braking, when the differential pressure exceeds the set value, the flow rate control valve operates and the orifice effect due to the flow passage restriction is generated, resulting in poor braking.

In view of the above, the present invention can obtain a slowly increasing pressure characteristic of the wheel cylinder due to the orifice effect during anti-skid control, and the difference between the master cylinder side hydraulic pressure and the wheel cylinder side hydraulic pressure during normal normal braking. Provided is an anti-skid brake device equipped with a flow control valve capable of enhancing a rapid braking effect by keeping a flow path open even when a pressure exceeds a set value.

[0005]

[Means for Solving the Problems]

 A main brake circuit that supplies brake fluid from the master cylinder to the wheel cylinder during normal braking, and a return circuit that pressurizes and recirculates brake fluid from the wheel cylinder to the main brake circuit side during anti-skid control are provided. The brake circuit operates according to the pressure difference between the master cylinder side hydraulic pressure and the wheel cylinder side hydraulic pressure, opens the flow path until the pressure difference reaches the set value, and when the pressure difference exceeds the set value. A structure in which a flow rate control valve for narrowing a flow path is provided, wherein the flow rate control valve includes a cylinder body, a piston provided in the cylinder body, and a wheel cylinder side which is separated from one side portion of the piston. The hydraulic pressure on the master cylinder side is introduced by being separated from the first hydraulic chamber where the hydraulic pressure is introduced to the other side of the piston, and this hydraulic pressure is applied to the wheel cylinder side. A second liquid chamber to be used, a third liquid chamber adjacent to the second liquid chamber, into which the hydraulic pressure on the master cylinder side is introduced via an orifice, and the piston in the second liquid chamber. A valve portion having a valve body which is opposed to and is elastically contacted by a spring at the piston end by a movement of the piston to open or restrict the flow path, and a rear end portion of the valve body The second liquid chamber and the third liquid chamber are separated from each other by penetrating the partition between the second liquid chamber and the third liquid chamber, and are provided in the third liquid chamber.

[0006]

[Action]

 During normal braking, the wheel cylinder fluid pressure acts on the first fluid chamber of the flow control valve, and the fluid pressure on the master cylinder side acts on the second fluid chamber and the third fluid chamber. Since the differential pressure between the 2nd fluid chamber and the 3rd fluid chamber is less than the set value, the valve body keeps the flow path open, and the brake fluid from the master cylinder is supplied to the wheel cylinder via the 2nd fluid chamber. To be done.

During the anti-skid control, the brake fluid in the wheel cylinder is discharged to the recirculation circuit to reduce the pressure in the wheel cylinder, so that the difference between the first fluid chamber, the second fluid chamber, and the third fluid chamber. When the pressure exceeds the set value, the valve element moves in the same direction as the piston moves to the first liquid chamber side, narrows the flow path, and exhibits the orifice effect.

When a high hydraulic pressure is generated in the master cylinder during sudden braking of the normal brake, the high-pressure brake fluid is introduced into the second hydraulic chamber, so that the differential pressure between the first hydraulic chamber and the second hydraulic chamber is increased. The piston moves to the first liquid chamber side above the set value, but the third liquid chamber maintains a lower pressure state than the second liquid chamber because the introduction of a sudden increase in master cylinder hydraulic pressure is restricted by the orifice. The valve body moves to the third liquid chamber side by the pressure difference between the second liquid chamber and the third liquid chamber to open the flow path, and supplies the high-pressure brake fluid from the master cylinder to the wheel cylinder.

[0009]

【Example】

 Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 1 exemplifies a brake fluid circuit for one wheel cylinder, where 1 is a brake fluid from a master cylinder 3 to a wheel cylinder 4 that generates fluid pressure according to the amount of depression of a brake pedal 2 during normal braking. The main brake circuit 5 supplies a recirculation circuit for recirculating the brake fluid in the wheel cylinder 4 to the main brake circuit 1 during anti-skid control. The main brake circuit 1 and the recirculation circuit 5 connect the master cylinder 3 and the wheel cylinder 4 to each other. It is connected in parallel between.

Reference numeral 6 is a normally open type inlet valve as a hydraulic pressure control valve arranged in the main brake circuit 1, and 7 is a normally closed type outlet valve as a hydraulic pressure control valve arranged in the reflux circuit 5. Each of the inlet valve 6 and the outlet valve 7 is controlled to be opened / closed in accordance with a skid state of a wheel by a control signal from a control unit (not shown).

In the return circuit 5, a reservoir 8 and a hydraulic pump 9 are arranged in this order on the discharge side of the outlet valve 7, and a damper chamber 10 is arranged on the discharge side passage of the hydraulic pump 9. The brake fluid discharged from the wheel cylinder 4 through the outlet valve 7 passes through the damper chamber 10 and is returned to the main brake circuit 1 side.

A flow rate control valve 20 is arranged between the inlet valve 6 and the confluence portion 11 of the main brake circuit 1 and the return circuit 5.

In this embodiment, a check valve 12 for returning the brake fluid from the wheel cylinder 4 to the master cylinder 3 when releasing the brake is provided in parallel with the inlet valve 6. The flow rate control valve 20 may be provided by-pass.

Reference numeral 21 denotes a cylinder body of the flow control valve 20, and the piston 22 and the liquid chamber partitioning member 23 are sequentially inserted and arranged in the cylinder body 21 from the opening end portion on one side, and the piston 22 A first liquid chamber 24 is formed on one side, a second liquid chamber 25 is formed on the other side of the piston 22, and a third liquid chamber 26 is formed adjacent to the second liquid chamber 25.

A spring seat 27 a is formed on the first pressure receiving surface 27 of the piston 22 facing the first liquid chamber 24, and a spring 28 is provided between the spring seat 27 a and the end wall of the first liquid chamber 24. The piston 22 is biased toward the second liquid chamber 25 side by being elastically mounted.

On the second pressure receiving surface 29 of the piston 22 facing the second liquid chamber 25, there is provided a push rod 29a which is formed in a pin-like shape from the center of the piston 22 so as to actuate a valve body 43 of a valve portion 40 described later. Has been formed.

A port 30 is formed in the first liquid chamber 24, and the hydraulic pressure of the wheel cylinder 4 is introduced from the port 30.

Two ports 31 and 32 are formed in the second liquid chamber 25. The port 31 is connected to the master cylinder 3 side, and the port 32 is connected to the inlet valve 6 side so that the master cylinder 3 The brake fluid from the side is supplied to the wheel cylinder 4 via the second fluid chamber 25.

The third liquid chamber 26 is formed in the liquid chamber partitioning member 23 itself, and a port 33 is formed in the third liquid chamber 26, and an orifice 34 is formed in the port 33, and the port 33 is formed. Is connected to the master cylinder 3 so that the hydraulic pressure of the master cylinder 3 is introduced through the orifice 34.

A valve section 40 is provided in the second liquid chamber 25 at an intermediate portion between the port 31 and the port 32.

The valve portion 40 has a valve seat 41 having an orifice groove 42 formed in the seating surface for narrowing the flow passage when the valve body is seated, and a substantially hemispherical valve urged by a spring 45 in the direction of seating on the valve seat 41. Body 43, and the valve seat 41 is arranged at a position surrounding the front end of the push rod 22a of the piston 22. In a normal state, the valve body 43 elastically contacts the end surface of the push rod 22a. It is separated from 41 so that the flow path can be opened.

A valve shaft 44 is projectingly provided at the center of the back surface of the valve body 43. The valve shaft 44 has a rear end portion thereof on the liquid chamber partitioning member 23. A bearing hole 46 formed penetrating the chamber 26 is slidably and liquid-tightly inserted and arranged, and the valve shaft rear end face faces the third liquid chamber 26 as a pressure receiving face 44a. ..

In the figure, 47 is a seal member mounted on each circumferential side of the piston 22 and the liquid chamber partitioning member 23, and 48 is a nut screwed to the open end of the cylinder body 21.

Next, the operation of the apparatus of the above embodiment will be described.

During normal braking, the hydraulic pressure generated in the master cylinder 3 acts on the second hydraulic chamber 25 according to the depression amount of the brake pedal 2, but the brake fluid in the wheel cylinder 4 is not discharged to the return circuit 5 side. Therefore, the differential pressure between the first liquid chamber 24 and the second liquid chamber 25 never exceeds the set value, and the piston 22 is in the set position. On the other hand, since the hydraulic pressure of the master cylinder 3 is also introduced into the third hydraulic chamber 26 via the orifice 34, the second hydraulic chamber 25 and the third hydraulic chamber 26 are kept at the same hydraulic pressure. Therefore, the valve body 43 is elastically contacted with the end of the push rod 22a of the piston 22 by the spring force of the spring 45 to keep the flow path open, and the brake fluid from the master cylinder 3 is opened to the second fluid chamber 25 and the open state. It is supplied to the wheel cylinder 4 via an inlet valve 6 and the internal pressure of the wheel cylinder 4 is increased to obtain a quick braking response.

At the time of anti-skid control, the outlet valve 7 is opened and the hydraulic pump 9 is operated, the brake fluid in the wheel cylinder 4 is discharged to the reflux circuit 5, and the wheel cylinder 4 is depressurized. , When the pressure difference between the first liquid chamber 24 and the second liquid chamber 25 exceeds the set value, the piston 22 moves to the first liquid chamber 24 side against the spring force of the spring 28, and the piston 22 is pushed. The end of the rod 22a is separated from the valve body 43 of the valve portion 40, and the seating restriction of the valve body 43 is released. At this time, the hydraulic pressure on the master cylinder 3 side is introduced into the third liquid chamber 26 via the orifice 34 in the same manner as described above, and the hydraulic pressure is the same as that of the second liquid chamber 25. Is seated by the spring force of the spring 45, the flow passage is narrowed to the open groove area of the orifice groove 42, and the orifice effect is exhibited, so that the gradual pressure increase characteristic of the wheel cylinder 4 can be obtained.

When a high hydraulic pressure is generated in the master cylinder 3 during sudden braking of the normal brake, this high-pressure brake fluid is introduced into the second hydraulic chamber 25, and the second hydraulic chamber 25 is rapidly increased in pressure. When the differential pressure between the first liquid chamber 24 and the second liquid chamber 25 becomes a set value or more, the piston 22 moves to the first liquid chamber 24 side and the end of the push rod 22a moves from the valve body 43 of the valve portion 40. The seat 43 is separated, and the seating restriction of the valve body 43 is released. However, the third liquid chamber 26 is kept at a lower pressure than the second liquid chamber 25 by restricting the introduction of the sudden increase in pressure of the master cylinder 3 by the orifice 34 of the port 33, and thus the second liquid chamber 25 is maintained. The valve body 43 moves toward the third liquid chamber 26 side against the spring force of the spring 45 by the pressure difference between the third liquid chamber 26 and the third liquid chamber 26, and maintains the flow path of the valve portion 40 in the open state. Therefore, the high-pressure brake fluid from the master cylinder 3 can be supplied to the wheel cylinder 4 through the second fluid chamber 25, and a quick braking response can be obtained.

[0029]

[Effect of the device]

 As described above, according to the present invention, during anti-skid control, the differential pressure between the hydraulic pressure on the master cylinder side and the hydraulic pressure on the wheel cylinder side is sensed to narrow the flow path of the valve section, and the wheel cylinder based on the orifice effect is detected. It is possible to obtain the slowly increasing pressure characteristic of the valve body, and when the normal braking is suddenly applied, the differential pressure is generated and the piston moves, so that even if the seating regulation of the valve body is released, the rear end of the valve body is installed, Since a differential pressure can be generated between the arranged third liquid chamber and the second liquid chamber to move the valve body in the flow passage opening direction, high-pressure brake fluid can be quickly supplied to the wheel cylinder. It has a practically great effect that the sudden braking response can be improved.

[Brief description of drawings]

FIG. 1 is a brake system diagram showing an embodiment of the present invention.

FIG. 2 is a schematic sectional view of a valve portion of the embodiment.

[Explanation of symbols]

1 ... Main brake circuit, 2 ... Brake pedal, 3 ... Master cylinder, 4 ... Wheel cylinder, 5 ... Reflux circuit, 2
0 ... Flow control valve, 21 ... Cylinder body, 22 ... Piston, 24 ... First liquid chamber, 25 ... Second liquid chamber, 26 ... Third liquid chamber, 34 ... Orifice, 40 ... Valve part, 43 ... Valve body, 45
…spring.

Claims (1)

[Scope of utility model registration request] 1. A main brake circuit that supplies brake fluid from a master cylinder to a wheel cylinder during normal braking, and a return circuit that pressurizes and recirculates brake fluid from the wheel cylinder to the main brake circuit side during anti-skid control. At the same time, the main brake circuit operates according to the differential pressure between the master cylinder side hydraulic pressure and the wheel cylinder side hydraulic pressure, and the flow path is opened until the differential pressure reaches the set value, and the differential pressure is set to the set value. In the structure described above, a flow control valve for narrowing the flow path is provided, and the flow control valve includes a cylinder body, a piston arranged in the cylinder body, and a wheel which is separated from one side of the piston. The first hydraulic chamber into which the hydraulic pressure on the cylinder side is introduced and the other side portion of the piston are separated from each other to introduce the hydraulic pressure on the master cylinder side, and the hydraulic pressure is applied to the wheel cylinder side. To act on the second liquid chamber, a third liquid chamber adjacent to the second liquid chamber, into which the hydraulic pressure on the master cylinder side is introduced via an orifice, and the second liquid chamber facing the piston. And a valve portion having a valve body that is elastically contacted and arranged by a spring at the end of the piston to open or throttle the flow passage by the movement of the piston, and the rear end portion of the valve body is provided with the second liquid chamber. An anti-skidded brake device characterized in that the anti-skidd brake device is provided by penetrating a partition between the third liquid chamber and the third liquid chamber.