JPH07215189A - Hydraulic control valve - Google Patents

Abstract

(57) [Summary] [Purpose] To prevent the occurrence of cavitation between the poppet valve body and the valve seat during a quick load. [Configuration] The apex angle of the valve seat 1 is gradually increased toward the inlet. The hydraulic fluid due to the rapid injection from the inlet side does not cause cavitation by being transmitted to the wheel cylinder side at a reduced flow velocity.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic control valve used in a hydraulic brake circuit of a vehicle or the like.

[0002]

2. Description of the Related Art FIG.
The hydraulic pressure control valve 10 disclosed in Japanese Patent No. 574 is shown. In this figure, an inlet 17 connected to the master cylinder, an outlet 18 connected to the wheel cylinder, and the inlet 17 and the outlet 18 are connected. Formed with the stepped hole 19, a stepped piston 20 movably inserted into the stepped hole 19, an inlet 17 and an outlet 1 for the piston 20.
And a through hole 20a formed by connecting the
A mortar-shaped valve seat 25 formed at the opening end on the inlet side of a
And the poppet valve body 4 arranged to face the valve seat 25.
0 and the valve seat 25 formed on the poppet valve body 40.
And a preload spring 28 that biases the piston 20 toward the outlet 18 side, and a valve spring that biases the poppet valve body 40 toward the valve seat 25. It is clear that

As is well known, the hydraulic pressure control valve 10 passes through the notch 40a of the poppet valve body 40 and the through hole 20a of the stepped piston 20 when hydraulic pressure is applied to its inlet 17 from the master cylinder side. A pressure liquid is applied from the outlet 18 to the wheel cylinder side to brake. The hydraulic pressure from the master cylinder side is a predetermined pressure (that is, preload spring 2
8) and the pressure receiving area difference on both sides of the stepped piston 20), the stepped piston 20 moves upward in the figure, and the valve seat 25 formed on the upper end of the stepped piston 20 moves to the poppet valve body 40. By contacting the protrusion 45, the master cylinder side and the wheel cylinder side are disconnected from each other, and when the hydraulic pressure on the master cylinder side further rises, the pressure in the smaller pressure receiving area increases with respect to the wheel cylinder side pressure. As a result, the stepped piston 20 moves downward. The pressure reduction control is performed as is known by repeating the seating and the separation of the poppet valve body 20 and the protrusion 45 as described above. However, when the brake is loosened, the stepped piston 20 moves downward and the poppet The protrusion 45 of the valve body 40 separates, and a large amount of brake fluid flows back between them from the wheel cylinder side to the master cylinder side, so that the brake is loosened. However, a large amount of brake fluid is contained in the poppet valve body. Since the poppet valve element 40 rapidly flows between the protrusion 45 of the valve 20 and the valve seat 25, the poppet valve element 40 has a spring force of its valve spring and the poppet valve element 40.
It receives a force that causes it to oscillate laterally at a resonance frequency determined by its mass.

However, the valve seat 25 formed at the tip of the stepped piston 20 has a mortar-shaped cross section as shown in FIG.
Alternatively, it has a triangular shape, and the apex angle α is set to 60 degrees. Conventionally, this α is 90 degrees, and when the brake is released, a large force is applied to vibrate the poppet valve body 40 in the lateral direction, which causes vibration to the left and right with respect to this axis, which may occur due to collision with the side wall of the valve hole. It was making a sound.
On the other hand, in the conventional example of FIG. 3, by setting the apex angle α to 60 degrees, the angle at which the brake fluid flows out is made small, and the force for vibrating the poppet valve body 40 in the lateral direction is made small to reduce the poppet valve body. It is possible to suppress the vibration of 40 and thus reduce the abnormal noise when the brake fluid is returned.

However, when the hydraulic fluid is rapidly transmitted from the master cylinder to the wheel cylinder side, that is, when the hydraulic fluid is suddenly loaded, the hydraulic fluid enters the gap formed between the valve seat 25 and the projection 45 of the poppet valve body 40. The poppet valve body 40 was damaged due to the rapid flow and the rapid constriction here, causing cavitation around the poppet valve body 40. That is, the projection 45 of the poppet valve body 40 and the valve seat 2
When the hydraulic fluid rapidly flows through the clearance between the poppet valve body 4 and the small gap 5, a large number of small bubbles are generated.
Was damaging 0.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and can reduce abnormal noise when the brake is loosened and can prevent cavitation around the poppet valve body when the vehicle is rushed. An object is to provide a hydraulic control valve.

[0007]

[Means for Solving the Problems] The above object is to provide an inlet communicating with the master cylinder, an outlet communicating with the wheel cylinder, and a stepped hole formed by communicating with the inlet and the outlet. A stepped piston movably inserted into the stepped hole, a through hole formed by connecting the piston with an inlet and an outlet, and a mortar-shaped valve seat formed at the inlet side opening of the through hole. A poppet valve element arranged to face the valve seat, a projection formed on the poppet valve element and seatable on the valve seat, and a preload spring for biasing the piston toward the outlet side. And a valve spring for urging the poppet valve element toward the valve seat, wherein the apex angle of the valve seat is gradually increased toward the inlet. Achieved by.

[0008]

[Function] Since the apex of the valve seat gradually increases toward the inlet, the gap between the projection of the poppet valve body and the valve seat gradually decreases during rapid loading, so that the abruptness increases rapidly. Even if the hydraulic fluid flows into this gap from the inlet side,
The cavitation is hardly generated from the beginning, and the cavitation is hardly generated because the diameter is gradually reduced toward the minimum gap portion. Therefore, damage to the poppet valve body due to cavitation is prevented.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A hydraulic control valve according to an embodiment of the present invention will be described below with reference to the drawings. The parts corresponding to those in FIG. 3 of the conventional example are denoted by the same reference numerals, and detailed description thereof will be omitted.

That is, the valve seat 1 formed at the upper end portion of the stepped piston 20 of this embodiment has a mortar shape as a whole, but a first straight portion 2 having an apex angle of 60 degrees from below, and The second straight portion 3 has a larger apex angle. Therefore, the gap 4 between the protrusion 45 of the poppet valve body 40 and the valve seat 1
Initially, the gap is relatively large when viewed from the inlet side (master cylinder side), so the gap is large, and the gap in the valve seat 1 is gradually reduced. Alternatively, the plunging speed of the hydraulic fluid into the through hole 20a of the stepped piston 20 is reduced.

The other structure is exactly the same as the conventional example.
Next, this operation will be described.

The operation at the time of first applying the brake is exactly the same as that of the conventional one, but when the brake pedal is suddenly depressed to make a quick withdrawal, the protrusion 45 of the poppet valve body 40 is as described above. , Valve seat 1 of stepped piston 20
Means that the desired braking force is obtained by repeating seating and leaving, but by applying this sudden braking, the stepped piston 20 is pressed downward and the state shown in FIG. 1 is obtained.
As a result, the gap 4 between the projection 45 of the poppet valve body 40 and the valve seat 1 is brought into a state as shown in the drawing, but the hydraulic fluid from the master cylinder is sufficiently laterally provided on the upper end side of the gap 4. As it extends, the hydraulic fluid is not rapidly throttled, but gradually toward smaller gaps. Therefore, the flow velocity of the hydraulic fluid flowing through the gap 4 also gradually increases. As a result, it is possible to prevent the occurrence of cavitation.
Therefore, it is possible to prevent the poppet valve body 40 from being damaged due to this.

FIG. 2 shows the essential parts of a hydraulic control valve according to another embodiment of the present invention. Similar to the first embodiment, parts corresponding to those of the conventional example are designated by the same reference numerals. , Its detailed description is omitted.

In this embodiment, the valve seat 5 formed at the upper end of the stepped piston 20 is composed of a straight portion 6 and an R portion (curved portion) 7 having an apex angle of 60 degrees from below. The gap 8 between the R portion 7 and the protrusion 45 of the poppet valve body 40 is large on the upper end side and extends laterally. That is, the apex angle gradually increases toward the upper end. Now the gap 8
Is gradually reduced toward the minimum gap.

With the above-described structure, when the brake is suddenly pressed, the state shown in FIG. 2 is taken and the hydraulic fluid is made to flow to the wheel cylinder side. At the entrance of the gap 8 , the valve seat 5 extends laterally. The gap is large in this portion, and gradually decreases toward the minimum gap portion below. Therefore, the hydraulic fluid having a high flow velocity due to the rapid injection is guided to the minimum clearance portion of the clearance 8 without being rapidly throttled, and flows toward the wheel cylinder through the axial through hole 20a of the stepped piston 20, but the passage 20a. Since the hydraulic fluid is gradually squeezed in the gap 8 when the hydraulic fluid flows into the inside, it is possible to prevent the poppet valve element 40 from being damaged due to this without causing cavitation.

Although each embodiment of the present invention has been described above, the present invention is not limited to this, and various modifications can be made based on the technical idea of the present invention.

For example, in the above embodiments, the vertical angle of the straight portions 2 and 6 of the valve seats 1 and 5 is set to 60 degrees, but it may be smaller than this.

Further, in the first embodiment, the valve seat 1 has the first straight portion 2
And the second straight line portion 3, the apex angle of the second straight line portion 3 is larger than the apex angle of the first straight line portion 2;
... It is possible to form a straight line portion and sequentially decrease the apex angle to gradually decrease the flow rate of the brake fluid at the time of sudden pressing.

Further, the shape of the poppet valve body 40 is not limited to the one shown in the figure, and is, for example, JP-A-3-246148.
The present invention is also applicable to a poppet valve body in which a passage is formed asymmetrically about the axial center thereof as disclosed in Japanese Patent Laid-Open Publication No.

[0023]

As described above, according to the hydraulic control valve of the present invention, the cavitation that occurs when the brake is pushed in is reduced while reducing the generation of the abnormal noise due to the vibration of the poppet valve body as in the conventional case. Can be prevented. Therefore, damage to the poppet valve body due to this is prevented.

[Brief description of drawings]

FIG. 1 is a sectional view of an essential part of a hydraulic control valve according to a first embodiment of the present invention.

FIG. 2 is a sectional view of an essential part of the second embodiment.

FIG. 3 is a sectional view of a conventional hydraulic control valve.

[Explanation of symbols]

 1 Valve Seat 2 1st Straight Part 3 2nd Straight Part 4 Gap 5 Valve Seat 6 Gap 7 R Part 8 Gap

Claims (1)

[Claims] 1. An inlet connected to a master cylinder, an outlet connected to a wheel cylinder, a stepped hole formed to connect the inlet and the outlet, and movably inserted into the stepped hole. A stepped piston, a through hole formed by connecting the piston to an inlet and an outlet, a mortar-shaped valve seat formed at an opening of the through hole on the inlet side, and the valve seat facing the valve seat. A poppet valve body, a projection formed on the poppet valve body that can be seated on the valve seat, a preload spring that biases the piston toward the outlet side, and the poppet valve body that serves as the valve seat. A fluid pressure control valve, comprising: a valve spring that biases the valve seat toward the valve seat, the valve seat having an apex angle gradually increasing toward the inlet.