JPS63266235A - Hydraulic shock absorber valve structure - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to a valve structure for a hydraulic shock absorber for a vehicle.

(Prior Art) A hydraulic shock absorber used in a motorcycle is, for example, as shown in FIGS. 5 and 6, in which a piston 53 attached to the tip of a piston rod 52 is slidably mounted inside a cylinder 51. A plurality of compression oil passages 54 and expansion oil passages 55 are formed in the piston 53, and petal-shaped valve seats 53a and 53b are integrally formed on both sides of the piston 53. A compression side valve 56 consisting of a disk-shaped valve that opens the oil passage 54 during the compression stroke, and an extension side valve 57 consisting of a disk-shaped valve that opens the oil passage 55 during the extension stroke are attached to both ends of the cylinder 53. Are known.

In this hydraulic shock absorber, when the piston 53 moves upward in the direction of arrow A during the compression stroke, the hydraulic oil in the upper oil chamber S1 passes through the compression side oil passage 54 and pushes down the compression side valve 56 to open it. It flows as shown by arrow C and flows into the lower oil chamber S2. Also, when the piston 53 moves downward in the direction of arrow B during the extension stroke, the hydraulic oil in the lower oil chamber S2 passes through the extension side oil passage 55 and pushes up the extension side valve 57 to open it, as shown by the arrow. The oil flows into the upper oil chamber S1.

(Problems to be Solved by the Invention) In the valve structure of the hydraulic shock absorber described above, disc-shaped valves are used as the compression side valve and the expansion side valve, so the compression side valve is connected to the expansion side oil passage. Since the extension side valve faces the inlet of the compression side oil passage, the flow of hydraulic oil is obstructed by the extension side valve and the compression side valve as shown by arrows C and D, meandering, and does not flow smoothly.
Cavitation occurs when the valve is pushed and deflected, making the damping force characteristics and temperature characteristics unstable.

Furthermore, since it is a circular disc valve, when it is pushed and bent by hydraulic oil, it bends in multiple directions, making the damping force curve characteristics unstable.

Furthermore, since the round surface of the valve seat formed on the piston is shaped like a flower petal, hydraulic pressure is applied to the part without the round surface and the valve flexes, impairing the sealing performance to the part with the round surface. Each characteristic becomes unstable.

(Means for Solving the Problems) In order to solve the above problems, the present invention provides a compression side valve and an expansion side valve in the shape of a disc-shaped valve with both sides cut out, and crosses both sides of the piston. They are mounted in a positional relationship, and the piston is provided with a compression side oil passage and an extension side oil passage at parts corresponding to both ends of each valve, as well as a round surface that follows the outer peripheral shape of each valve.

(Function) Each valve has a shape obtained by cutting out both sides of a disc-shaped valve, and is mounted on the piston in an intersecting positional relationship, and oil passages are formed at parts corresponding to both ends of each valve. , the extension side valve no longer blocks the compression side oil passage, and the compression side valve no longer blocks the extension side oil passage, making the flow of hydraulic oil smoother, and even when it is pushed and deflected by the hydraulic oil, the direction of deflection is consistent. The round surface of the piston that receives each valve follows the outer circumferential shape of the valve, which improves sealing performance.

(Example) Embodiments of the present invention will be described below based on the accompanying drawings.

Fig. 1 is a sectional view of a hydraulic shock absorber to which the valve structure according to the present invention is applied, Fig. 2 is an enlarged sectional view of the main part of Fig. 1, Fig. 3 is a top view of the piston part of Fig. 2, and Fig. 4 The figure is a bottom view of the 251i piston section.

The hydraulic shock absorber l has a hollow rod 3 inserted into a cylinder 2 filled with hydraulic oil, and a piston 4 fixed to the tip of the hollow rod 3. It is divided into a chamber St and a lower oil chamber S2.

An upper metal 6 is attached to the upper part of the cylinder 2, and a sub-tank 7 that communicates with the upper oil chamber S1 is attached to the upper part, and the hollow rod 3 has a damping force adjustment mechanism 8 built inside, and a spring seat 9 and a lower metal part are attached to the lower end. 10 is added, and a spring seat 12 and a hollow rod 3 are screwed into a screw 11 carved on the outer peripheral surface of the cylinder 2 so as to be able to move up and down.
A suspension spring 13 is stretched between the spring seat 9 and the lower end of the spring seat 9.

Further, an extension valve 15 having a drum-like shape obtained by cutting both sides of a disk-shaped valve is fitted above the piston 4, and a valve stopper 16 is fitted above the extension valve 15.
Further, a compression side valve 17 having a drum-like shape obtained by cutting both sides of a disk-shaped valve is fitted under the piston 4, and a valve stock is installed under the compression side valve 17. -/pa 18 is installed, and the expansion side valve 15 and compression side valve 17 are installed in a positional relationship that intersects with each other with a 90° phase.

On the side of the piston 4, extension side oil passages 19 are formed in the axial direction at parts corresponding to both ends of the extension side valve 15, and extension side oil passages 19 are formed in axial directions at parts corresponding to both ends of the compression side valve 17. A plurality of compression side oil passages 20 are formed in. Further, a round surface 21 that follows the outer peripheral shape of the expansion side valve 15 is formed on the upper surface of the piston 4, and a round surface 22 that follows the outer peripheral shape of the compression side valve 17 is formed on the lower surface of the piston 4.

The operation of the valve structure constructed as described above will be explained below.

First, when the cylinder 2 descends and the piston 4 moves relatively upward during the compression stroke of the hydraulic shock absorber 1, the volume of the upper oil chamber S1 decreases and the hydraulic oil in the upper oil chamber S1 is pressurized. , whereby the hydraulic oil in the upper oil chamber S1 is
As shown, the oil flows through the compression side oil passage 20 of the piston 4, pushes down the compression side valve 17, is generated between the lower surface of the piston 4, and flows into the lower oil chamber S2 from the opening.

In this case, the extension valve 1 installed on the upper side of the piston 4
Since the portion located on the compression side oil passage 20 of No. 5 is cut off and there is nothing blocking the inlet side of the compression side oil passage 20, the hydraulic oil flows smoothly. Further, since the compression side valve 17 has a drum-like shape, both ends are bent downward by the hydraulic oil applied from the oil passage 20, but since this bending is in one direction, it is easy to set the damping force. Furthermore, the extension side valve 15
Since hydraulic pressure is applied from above, the round surface 21 of the piston 4 follows the outer circumference of the extension-side valve 15, so the outer circumference of the extension-side valve 15 is uniformly pressed against the round surface 21 and deformed by an uneven load. Never.

Next, when the cylinder 2 rises and the piston 4 moves relatively downward during the extension stroke of the hydraulic shock absorber l, the volume of the lower oil chamber S2 decreases and the hydraulic oil in the lower oil chamber S2 is pressurized. . As a result, the hydraulic oil in the lower oil chamber S2 passes through the extension side oil passage 19 of the piston 4, pushes up the extension side valve 15, and is generated between the lower surface of the piston 4 and the upper oil from the opening. It flows into the chamber S1.

In this case, the compression side valve 1 attached to the lower side of the piston 4
Since the portion located below the extension side oil passage 19 of 7 is cut off and there is nothing blocking the inlet side of the extension side oil passage 19, the hydraulic oil flows smoothly. In addition, since the extension side valve 15 has a drum-like shape, both ends are bent upward by the hydraulic oil applied from the oil passage 19, but this bending is in one direction, making it easy to set the damping force. Become. Furthermore, compression side valve 1
Hydraulic pressure is applied to piston 7 from below, but since the round surface 22 of the piston 4 follows the outer periphery of the compression valve 17, the outer periphery of the compression valve 17 is uniformly pressed against the round surface 22 and deformed by the uneven load. There's nothing to do.

(Effects of the Invention) As explained above, according to the present invention, the compression side valve and the expansion side valve are each shaped like a circular valve with both sides cut out, and are mounted on the piston in an intersecting positional relationship. Oil passages are formed in the piston at locations corresponding to both ends of each valve, so the extension side valve no longer blocks the compression side oil passage of the compression side valve, and the compression side valve no longer blocks the extension side oil passage of the compression side valve.
The flow of hydraulic oil becomes smoother, and the damping force characteristics and temperature characteristics become stable, and even when the hydraulic oil is pushed and deflected, the direction of deflection is unidirectional, functioning like a leaf spring, resulting in damping force curve characteristics. Furthermore, since the round surface of the piston that receives each valve follows the outer peripheral shape of the valve, the sealing performance is improved and each characteristic is stabilized.

[Brief explanation of drawings]

Fig. 1 is a sectional view of a hydraulic shock absorber to which the valve structure according to the present invention is applied, Fig. 2 is an enlarged sectional view of the main part of Fig. 1, Fig. 3 is a top view of the piston part of Fig. 2, and Fig. 4 The figure is a bottom view of the piston part in FIG. 2, and FIGS. 5 and 6 are a sectional view and a guide view showing a conventional valve structure. In the figure, 1 is a hydraulic shock absorber, 2 is a cylinder, 4 is a piston, 15 is an extension side valve, 17 is a compression side valve, 19 is an extension side oil passage, 20 is a compression side oil passage, and 21.22 is a round. It is a surface. Patent applicant Showa Seisakusho Co., Ltd. Agent
Patent Attorney Part 2 1) Patent Attorney Kuni Ohashi Part 1 Patent Attorney Yuyuki Koyama Patent Attorney No 1)
Shigeru Figure 2 Figure 3 Figure 4 Figure 5

Claims (1)

[Claims] In a hydraulic shock absorber in which a compression side oil passage and an extension side oil passage are formed in the piston, and a compression side valve and an expansion side valve are provided corresponding to these compression side oil passage and extension side oil passage, each of the above-mentioned valves is Shaped by cutting off both sides of the disc-shaped valve,
A valve of a hydraulic shock absorber, characterized in that the cut-out part of the compression-side valve faces the inlet of the compression-side oil passage, and the cut-out part of the extension-side valve faces the inlet of the compression-side oil passage. structure.