JPH11325283A - Check valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To show stable performance of a check valve even under application of high pulsative pressure by expanding a terminal of the coil spring on the side of a spring seat from other portions outward in a winding direction, and providing the coil spring pressing the terminal against the inner wall of a valve housing. SOLUTION: A coil spring 5 gradually shows a large diameter toward a terminal 5a on the side of a spring seat. The terminal 5a is projected outward from other portions of the coil spring 5, providing an outermost diameter d3 greater than an inner diameter of a case. The coil spring 5 is thus attached in the case while pressing the terminal 5a inward. The coil spring 5, other than the terminal 5a, having a diameter not more than a diameter d1 is held by three projections in the case. The terminal 5a is pressed against the inner wall of the case with constant force. When pulsative hydraulic pressure, showing 15 MPa at the highest intensity, is repetitively applied, the coil spring 5 may be rotated together with a movable valve element. However, the terminal 5a is kept contact with the inner wall of the case.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a check valve, and more particularly to an improvement of a check valve used in a hydraulic system to which a pulse pressure is applied.

[0002]

2. Description of the Related Art In a check valve, a movable valve body is urged in a valve closing direction by a coil spring mounted inside the check valve. When a high pulse pressure of a fluid (oil or the like) is repeatedly applied to the check valve, the coil spring rotates together with the movable valve body and receives a force pushed to the discharge port side. As a result, the terminal portion of the coil spring may protrude from the discharge port to the outside. When the terminal of the coil spring protrudes from the discharge port, the coil spring does not function properly. Specifically, the pulse pressure of the hydraulic pressure of 10 to 12 MPa is the withstand pressure limit of the conventional check valve. On the other hand, when a high pulse pressure is applied, the terminal portion of the coil spring may be lifted and entangled with another coil portion. When such entanglement occurs, the coil spring can no longer function as a "spring". As described above, when the conventional check valve is used in a hydraulic system or the like to which a high pulse pressure is likely to be applied, a malfunction may be caused.

[0003] In view of the above-mentioned conventional problems, an object of the present invention is to provide a check valve that exhibits stable performance even when a high pulse pressure is applied.

[0004]

SUMMARY OF THE INVENTION A check valve according to the present invention has a valve housing having a valve seat and a fluid supply port at one end, and a spring receiving portion and a fluid discharge port at the other end. In the valve housing, a movable valve body provided so as to be able to contact and separate from the valve seat, and disposed between the spring receiving portion and the movable valve body to press the movable valve body against the valve seat. The coil spring is biased to form a terminal portion on the side of the spring receiving portion bulging outward from the other portion, and the terminal portion is provided with a coil spring pressed against the inner wall of the valve housing ( Claim 1). In the check valve configured as described above, a terminal portion formed so as to protrude outward from the other portion of the coil spring is always stuck to the inner wall of the valve housing with a constant force. Therefore, even if the pulse pressure of the fluid is applied to the check valve,
The end of the coil spring is not lifted or protruded from the outlet of the valve housing.

[0005] In the above check valve, the terminal portion of the coil spring may be bonded to a corresponding portion of an adjacent coil at a position a predetermined distance from an end of the coil spring. In this case, the range in which the terminal portion can freely move is limited to a predetermined length from the adhesive portion to the end. Therefore, the entanglement between the terminal portion and another coil portion is prevented.

[0006]

FIG. 1 is a view showing a check valve according to a first embodiment of the present invention. FIG. 1 (a) is a vertical sectional view, and FIG. 1 (b) is a BB line in FIG. 1 (a). It is sectional drawing. In the drawing, a check valve 1 includes a case 2, a valve seat 3 attached to an upper end of the case 2, a movable valve body 4 arranged to be able to contact and separate from the valve seat 3, and a movable valve body 4. And a coil spring 5 that is mounted between the spring member 2a and the lower part of the case 2 and urges the movable valve body 4 upward and presses the movable valve body 4 against the valve seat 3. The case 2 is a "valve housing" together with the valve seat 3.
Is composed.

FIG. 2 is a diagram showing only the case 2.
(A) is a plan view, (b) is a vertical sectional view. Case 2
Has a spring receiving portion 2a and three protruding pieces 2c at the bottom, and the other cutout portion is a fluid discharge port 2b. The projecting piece 2c is formed to be inclined upward by 60 degrees, and has a role of holding the coil spring 5 (FIG. 1) in the case 2. FIG. 3 is a diagram showing only the valve seat 3,
(A) is a vertical sectional view, and (b) is a bottom view. Valve seat 3
Has a dish-like shape provided with a fluid supply port 3a at the center. FIG. 4 is a diagram showing only the movable valve body 4,
(A) is a plan view, (b) is a vertical sectional view. At three locations around the movable valve body 4, there are provided engagement portions 4 a for engaging the inside of the case 2 (FIG. 1) to maintain the posture of the movable valve body 4. An escape hole 4b for the high-pressure fluid is formed at the center.

FIG. 5 is a view showing the coil spring 5.
(A) is a vertical cross-sectional view, (b) is a plan view showing only one extra lower portion of the coil spring 5. In FIG. 5 with reference to FIG. 1, the coil spring 5 has a winding diameter d1 on the spring receiving portion 2a side.
(Numerical example 7.46 mm) is larger than the winding diameter d2 on the movable valve body 4 side (Numerical example 4.46 mm). Further, the end portion 5a (the hatched portion in FIG. 5B) on the spring receiving portion side gradually increases in radius toward the end, so that the terminal portion 5a extends outward from the other portions of the coil spring 5. The case 2 bulges and its maximum outer diameter d3 (numerical example 8.5 mm) is larger than the inner diameter d4 of the case 2 (FIG. 2, numerical example 8.3 mm). Accordingly, the coil spring 5 compresses the terminal portion 5a inward while the case 2
It is installed inside. When mounted, the portion of the coil spring 5 having the winding diameter d1 excluding the terminal portion 5a is held by the three projecting pieces 2c of the case 2, and the terminal portion 5a is pressed against the inner wall of the case 2 with a substantially constant force (FIG. 1 (b)).

As a result of conducting a hydraulic pressure application experiment on the check valve 1 having the coil spring 5 mounted as described above, when a pulse pressure of a maximum hydraulic pressure of 15 MPa is repeatedly applied,
Although the coil spring 5 may rotate with the movable valve body 4, the terminal portion 5 a is always stuck to the inner wall of the case 2. That is, the terminal 5a of the coil spring 5 did not protrude from the discharge port 2b of the case 2. Also, the terminal 5a was not lifted.

FIG. 6 is a view showing a coil spring 5 of a check valve according to a second embodiment, wherein (a) is a vertical sectional view and (b).
FIG. 3 is a plan view showing only about 1.5 lines below the coil spring 5. The configuration other than the configuration related to the coil spring 5 is the same as that of the first embodiment. The difference between the configuration of the coil spring 5 shown in FIG. 6 and the coil spring 5 of the first embodiment is that, as shown in FIG. Are partially adhered by solder 6 or brazing or welding.

By performing such bonding, the terminal portion 5a becomes a portion in which only a predetermined length from the starting point 5b to the end can freely move. In other words, the free movement of the terminal unit 5a is considerably restricted. In addition, due to the bonding, the positional relationship in which the lowermost coil including the terminal portion 5a is always lower than the coil one layer above it is maintained. This is advantageous, for example, when the coil spring 5 is mounted.
In order to mount the coil spring 5 on the case 2, FIG.
The coil spring 5 is inserted from above the case 2 shown in FIG.
In the coil spring 5 of the first embodiment, when the terminal portion 5a, which is to be expanded outward, is to be inserted while being compressed, the terminal portion 5a pops out and enters the inside of the coil spring 5 or rises upward to form a strip. In some cases, entanglement may occur and quick mounting work may not be possible. However, the coil spring 5 of the second embodiment does not have such a disadvantage. Therefore, the mounting work becomes easy. Also, after mounting,
In the coil spring 5 of the second embodiment, the terminal portion 5a is unlikely to float upward, so that entanglement with other coil portions is prevented.

The shape of the coil spring 5 is not limited to those shown in the first and second embodiments, and various forms are possible. 7 and 8 are views showing coil springs 5 having other shapes. FIG. 7 shows a terminal portion 5a which is extended substantially linearly in a tangential direction so as to bulge outward from other portions. Is shown. FIG. 8 shows the terminal portion 5a which is extended substantially linearly in the tangential direction and then bent inward.

[0013]

The present invention configured as described above has the following effects. According to the check valve of the first aspect, since the terminal portion of the coil spring is always stuck to the inner wall of the valve housing with a constant force, even if pulse pressure is applied to the check valve, the terminal portion of the coil spring can be used. No part is lifted or protruded from the outlet of the valve housing. Therefore, it is possible to provide a check valve exhibiting stable performance even with a high pulse pressure.

According to the check valve of the second aspect, the range in which the terminal portion can freely move is limited, and movement of the terminal portion and entanglement between the terminal portion and another coil are prevented. Therefore, it is possible to provide a check valve that allows easy installation of the coil spring and exhibits more stable performance against a high pulse pressure after the installation.

[Brief description of the drawings]

1A is a vertical sectional view showing a check valve according to an embodiment of the present invention, and FIG. 1B is a sectional view taken along line BB of FIG.

FIG. 2 is a view showing only a case of the check valve,
(A) is a plan view, (b) is a vertical sectional view.

FIG. 3 is a view showing only a valve seat of the check valve, and FIG.
Is a vertical sectional view, and (b) is a bottom view.

FIG. 4 is a view showing only a movable valve body of the check valve;
(A) is a plan view, (b) is a vertical sectional view.

FIG. 5 is a view showing a coil spring of the check valve.

FIG. 6 is a diagram illustrating a coil spring in a check valve according to a second embodiment.

FIG. 7 is a diagram showing a coil spring having another shape according to the present invention.

FIG. 8 is a diagram showing a coil spring of still another shape according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Check valve 2 Case 2a Spring receiving part 2b Discharge port 3 Valve seat 3a Supply port 4 Movable valve element 5 Coil spring 5a Terminal part 6 Solder

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Muneori Adachi 3-5-8 Minamisenba, Chuo-ku, Osaka-shi Koyo Seiko Co., Ltd.

Claims (2)

[Claims] A valve housing having a valve seat and a fluid supply port on one end side and a spring receiving portion and a fluid discharge port on the other end side; A movable valve body that is provided so as to be disposed between the spring receiving portion and the movable valve body to urge the movable valve body in a direction of pressing the movable valve body against the valve seat, and a terminal portion on the spring receiving portion side Is formed so as to bulge outwardly from the other portion of the valve housing, and the terminal portion includes a coil spring that presses against the inner wall of the valve housing. 2. The check valve according to claim 1, wherein the terminal portion of the coil spring is bonded to a corresponding portion of an adjacent coil at a position a predetermined distance from an end of the coil spring.