JPH0719358A - Check valve - Google Patents

Abstract

PURPOSE:To provide a check valve to be provided in a fluid passage like a bypass passage of a hydraulic buffer which has a simple structure, facilitates assembly and disassembly of each member, eliminates irregularity in valve opening pressure of individual check valve, facilitates its adjustment, is inexpensive, and has excellent durability. CONSTITUTION:In a check valve 20 which blocks a fluid passage 21 provided in a member 4 by a spherical valve element 22, an elastic O ring 23 is mounted on the member 4 in such a manner that it surrounds outer periphery of the member 4 including the part of the check valve 20, and the spherical valve element 22 is held on a valve seat by the O ring 23.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a check valve having a spherical valve body suitable for installation in a fluid passage such as a bypass passage provided in a rod guide portion of a hydraulic shock absorber.

[0002]

2. Description of the Related Art In a hydraulic shock absorber provided with an oil reservoir having a space formed by a gas such as an inert gas on the outer periphery of an oil chamber inside a cylinder filled with hydraulic oil, the gas in the oil reservoir is For some reason, it may be mixed in the oil chamber, which causes gas to accumulate in the upper part of the oil chamber, and the damping force characteristic of the shock absorber may change and become unstable.

Therefore, in order to return the gas accumulated in the upper part of the oil chamber to the oil reservoir, a bypass passage for returning the gas accumulated in the upper part of the oil chamber to the oil reservoir is provided in the rod guide portion in the upper part of the cylinder. It has been conventionally performed to provide a check valve having a spherical valve body in this bypass passage in order to prevent the gas from entering the oil chamber from the oil reservoir.

As shown in FIG. 5, a check valve formed by a spherical valve element installed in the bypass passage of the rod guide portion of such a hydraulic shock absorber has a return spring 27 held by a stopper 28 so that it is spherical. Valve body 22
A structure in which the bypass passage is closed by pressing the valve seat against the valve seat is conventionally known.

[0005]

By the way, according to the check valve of the conventional structure as described above, when the check valve is installed in the bypass passage of the rod guide portion, the rod guide portion is provided with a hole for attaching the stopper. Since it is necessary to drill according to the position of the check valve, machining of the rod guide itself becomes troublesome, the bypass passage and the check valve are small, and the return spring and stopper incorporated therein are also small members. Therefore, its assembly and disassembly become extremely troublesome.

Further, since the bypass passages are usually provided at a plurality of locations in the rod guide portion, if there is variation in the spring force of each return spring of the check valve installed in each bypass passage, the bypass passages have different variations. There is a problem that the valve opening pressure between the stop valves appears to be non-uniform, and it is also difficult to adjust the valve opening pressure.

An object of the present invention is to eliminate the above-mentioned inconveniences of the conventional check valves, and more specifically, a check valve installed in a fluid passage such as a bypass passage of a hydraulic shock absorber. The structure of the stop valve itself is simple, each member can be easily assembled and disassembled, there is no uneven opening pressure of each check valve, and its adjustment is easy, and it is cheap and durable. The purpose is to have excellent properties.

[0008]

SUMMARY OF THE INVENTION In order to solve the above problems and to achieve the object, the present invention provides a check valve in which a fluid passage provided in a member is closed by a spherical valve body.
The O-ring having elasticity is attached to the member so as to surround the outer circumference of the member including the check valve portion, and the spherical valve element is held on the valve seat by the O-ring.

[0009]

[Operation] With the above-described structure, even if a plurality of fluid passages are provided in a member, the valve bodies can be simultaneously valved to those fluid passages by simply installing one O-ring. It can be retained in the seat, and the check valve can be easily installed in the plurality of fluid passages.

Since one common O-ring acts on each check valve installed on the member with equal force, the opening pressure of each check valve becomes uniform and the check valve opens. The adjustment of the valve pressure is also performed once for each check valve by a simple operation of simply replacing the O-ring and changing the interference.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A check valve according to the present invention will be described below with reference to the accompanying drawings.

FIG. 1 shows an outline of a hydraulic shock absorber itself to which a check valve of the present invention is applied. In the hydraulic shock absorber 1, a piston 6 at the tip of a piston rod 5 is provided inside a cylinder 2. Upper oil chamber 8A and lower oil chamber 8B that are defined
However, oil storage chambers 9 defined by the cylinder 2 and the outer shell 3 are formed on the outer circumference of the cylinder 2.

The oil chambers 8A, 8B inside the cylinder 2 are filled with hydraulic oil, and the oil reservoir chamber 9 on the outer periphery of the cylinder 2 is filled with oil inside the cylinder 2 due to a change in the volume of the piston or a change in temperature. In order to compensate for the fluctuation of the quantity, a space 9A made of an inert gas such as N ₂ is provided.

The piston rod 5 is slidably held by the rod guide portion 4.
Oil passages 10 and 11 that connect the oil chamber 8A and the oil chamber 8B to each other are formed in the piston 6 at the tip of the oil passage 10. A check valve 14 that opens during the compression stroke is provided in the oil passage 10 and an extension stroke is provided in the oil passage 11. A check valve 15 and a throttle portion 16 which are sometimes opened are provided respectively.

Oil passages 12 and 13 for connecting the oil chamber 8B and the oil reservoir chamber 9 are formed in the bottom portion 7 located at the lower ends of the oil chamber 8B and the oil reservoir chamber 9, and the oil passage 12 has a throttle portion. However, the oil passage 13 is provided with a check valve 18 that opens during the extension stroke.

In the hydraulic shock absorber 1, during the compression stroke, the hydraulic oil in the oil chamber 8B flows into the oil chamber A through the oil passage 10 of the piston 6 and also enters the oil chamber 8A from the outside. Hydraulic oil equivalent to the volume of the rod 5 is transferred to the bottom portion 7.
The oil flows from the oil chamber 8B into the oil sump chamber 9 through the narrowed portion 17 of the flow path 12. The damping force generated at this time is adjusted to an appropriate one by the throttle portion 17.

During the extension stroke, the working oil in the oil chamber 8A flows into the oil chamber 8B through the oil passage 11 of the piston 6, and at the same time, the volume of the piston rod 5 flowing out from the oil chamber 8A to the outside. The hydraulic oil of No. 2 flows into the oil chamber 8B from the oil reservoir 9 through the flow path 13 of the bottom portion 7. The damping force generated at this time is adjusted to an appropriate one by the diaphragm portion 16.

In the hydraulic shock absorber 1 as described above, the gas in the oil sump chamber 9 is changed to the oil in the cylinder 2 due to the shock of the shock absorber sideways and the bubbling in the oil sump chamber due to the rapid flow of hydraulic oil. The gas may enter the chamber and accumulate in the upper part of the oil chamber 8A, which may change the damping force characteristic of the shock absorber to make it unstable.

Therefore, a bypass passage having a check valve 20 is provided in the rod guide portion 4 so as to connect the oil chamber 8A and the oil reservoir chamber 9, whereby the bypass passage is reserved above the oil chamber during the extension stroke. The gas is returned from the oil chamber 8A to the oil reservoir 9 and, at the same time, the gas is prevented from invading the oil chamber 8A from the oil reservoir 9 during the compression stroke.

An embodiment of the check valve of the present invention installed in the bypass passage of the rod guide portion 4 of the hydraulic shock absorber 1 as described above will be described below with reference to FIGS.

As shown in FIG. 2, the seal members 31, 32 are
The rod guide portion 4 fitted to the upper ends of the cylinder 2 and the outer shell 3 via the bearing slidably holds the piston rod 5 in the center through the bearing 33, the main oil seal 34, the dust seal 35, and the like. Thus, the cap 36 covers the upper part thereof.

The rod guide portion 4 includes a bypass passage 21.
The oil chamber 8A inside the cylinder 2 and the oil storage chamber 9 on the outer circumference of the cylinder 2 are penetrated by a gap between the oil-bearing bearing 33 and the piston rod 5, and the rod guide portion 4 and the piston rod. The gap between the oil chamber 8A and the oil reservoir 8 is irreversibly communicated with the oil chamber 8A by the bypass passage 21 having the check valve 20.

The bypass passage 21 is, as shown in FIG.
It is provided at three locations on the same plane at substantially the same angle from the center of the rod guide portion 4, each bypass passage 21 is provided with a check valve 20, and each check valve 20 has a spherical valve. One common O-ring 23 is arranged so as to contact the outside of the body 22.

The check valve 20 is installed in the vicinity of the opening of the bypass passage 21 on the oil reservoir 9 side. As shown in FIG. 4, the spherical valve body 22 has an outer side (oil reservoir 9). It is held so as to be pressed against the valve seat 24 by an O-ring 23 made of elastic synthetic resin, rubber or the like disposed on the side).

The inner diameter of the O-ring 23 is the same as or slightly smaller than the circle passing through the outer apex of each valve element 22 in the seated state, and the O-ring 23
When the valve bodies 22 are seated on the valve seats 24, they are in contact with the outside of each valve body 22 with little elastic deformation or in a slightly expanded state.

Regarding the sectional shape of the O-ring 23,
In the illustrated embodiment, the shape is a vertically elongated elliptical shape close to a perfect circle, but the shape is not limited to such a shape, and may be a quadrangle or any other suitable shape.

An annular groove 25 is provided on the outer circumference of the rod guide portion 4 so as to pass through the outside of each check valve 20, and an O-ring is fitted therein. The inner diameter of the groove 25 from the center of the rod guide portion 4 is
As shown in FIGS. 3 and 4, the diameter is the same as the circle passing through the outer apex of each valve body 22 in the seated state.

The annular groove 25 serves as a positioning means when the O-ring is mounted and prevents the O-ring from being displaced after the mounting. In this embodiment, the inner diameter of each of the valve bodies is as described above. Although the diameter is the same as the circle passing through the outer apex of 22, the diameter may be smaller than this.

The O-ring positioning and movement preventing means may be provided by, for example, providing projections above and below the O-ring mounting position, and is not limited to the groove 25.

The check valve 20 as described above includes an O-ring 23.
The valve body 22 is pressed against the valve seat 24 by the valve closed state, and the bypass passage 21 is moved from the oil chamber 8A side to the oil reservoir 9
When the fluid flows to the side, the valve body 22 is separated from the valve seat 24 while being elastically deformed by the pressure so as to extend so that the O-ring 23 is opened and the valve is opened. When the fluid flow stops, the extended O-ring 23
The valve body 22 is pushed back to the valve seat 24 by the contraction due to the elastic restoring force of, and returns to the original closed state.

In the hydraulic shock absorber 1 having the check valve 20 as described above, the check valve 20 is assembled to the rod guide portion 4,
The disassembly and adjustment of the valve opening pressure can be performed very easily, and the check valve 20 prevents the reverse penetration of gas into the cylinder 2 and stabilizes the damping force characteristic thereof.

Although the check valve of the present invention has been described above by way of an embodiment in which it is applied to a fluid passage of a member called a rod guide portion of a hydraulic shock absorber, the present invention is limited to the above-mentioned ones. Rather, it is a check valve that closes the fluid passage with a spherical valve body, and the member itself in which the fluid passage is provided can be mounted so as to surround its outer periphery with an elastic O-ring. Needless to say, it is widely and generally applicable regardless of its use.

[0033]

According to the present invention as described above, for example, a check valve having a spherical valve body, which is installed in a bypass passage of a rod guide portion of a hydraulic shock absorber, has a structure itself. Simple, easy to assemble and disassemble each member,
The non-uniformity of the opening pressure of each check valve does not occur, its adjustment is easy, and it is inexpensive and has excellent durability.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing an outline of a hydraulic shock absorber to which a check valve of the present invention is applied.

FIG. 2 is a vertical sectional view showing an embodiment in which the check valve of the present invention is applied to a bypass passage of a rod guide portion of a hydraulic shock absorber.

3 is a cross-sectional view showing a portion of a bypass passage and a check valve of the rod guide portion shown in FIG.

FIG. 4 is a partially enlarged vertical sectional view showing a bypass passage and a check valve portion of the rod guide portion shown in FIG.

FIG. 5 is a longitudinal sectional view showing a conventional example of a check valve installed in a bypass passage of a rod guide portion of a hydraulic shock absorber.

[Explanation of symbols]

 4 member (rod guide part) 20 check valve 21 fluid passage (bypass passage) 22 spherical valve body 23 O-ring

Claims (1)

[Claims] 1. A check valve in which a fluid passage provided in a member is closed by a spherical valve body, and an elastic O-ring is attached to the member so as to surround the outer circumference of the member including the check valve portion. The check valve is characterized in that the spherical valve element is held on the valve seat by the O-ring.