JPH01164830A - Hydraulic buffer - Google Patents

Abstract

PURPOSE:To prevent lowering of a damping force and decrease of a spring constant during actuation, by a method wherein the upper part of a reservoir is communicated to the inner upper part of an inner cylinder through a check valve, and a breeder valve is communicated to the upper part of a cylinder. CONSTITUTION:During working of a hydraulic buffer, air present in a reservoir 3 opens a check valve 28 flows through a communicating groove 26 and further flows through a space 25 and a hole 30 and is discharged in the open air after it opens a breeder valve 13. Air present in a piston upper chamber 16 flows in a space 17, and air present spaces 17 and 18 flows through a slit 27, the space 25, and the hole 30 to open the breeder valve 13, and is discharged in the open air. Further, since the check valve 28 is situated to the upper part of the reservoir 3, air in the space 25 is prevented from flowing in the reservoir 3. Rapid discharge of the air enables prevention of lowering of a damping force and reduction of a spring constant during working of a hydraulic buffer.

Description

DETAILED DESCRIPTION OF THE INVENTION "Field of Industrial Application" The present invention relates to a hydraulic shock absorber having a damping force generating mechanism within a cylinder.

``Prior Art'' As is well known, a hydropneumatic shock absorber is installed between the body of an automobile and the axle to adjust the vehicle height and absorb sudden changes in the axle. A suspension (hereinafter abbreviated as suspension) is installed.

As a conventional suspension of this type, for example, a suspension suspension as shown in FIG. 2 is known.

This suspension has an inner cylinder 1 of a double cylinder consisting of an inner cylinder 1 and an outer cylinder 2.

A reservoir 3 is formed between the outer cylinder 2, and a rod guide 4 is provided at the upper part of the inner cylinder 1 and the reservoir 3. A piston 8 is slidably inserted into the inner cylinder 1 at the lower end of a rod 7 that is slidably inserted into the seal member 5 and the lock ring 6.
is attached to the piston 8, and a damping force generating mechanism, that is, a communication hole 9. Damping valves IOa and 10b are provided, and the piston lower chamber 11
and the reservoir 3 are communicated through a communication hole 12, and a bleeder valve 13 attached to the outer cylinder 2 is communicated with the upper part of the reservoir 3. Pressure oil is supplied into the cylinder through a passage 14 provided at the center of the rod 7 to raise the vehicle height, and the vehicle is held at a predetermined height position to buffer sudden changes in the axle. When the load on the vehicle decreases and the height of the vehicle increases, the pressure oil in the cylinder is returned to the pressure oil supply source to lower the height of the vehicle and adjust the vehicle height. Note that 15 is an O-ring.

In this type of suspension, when pressure oil is supplied into the cylinder, if air exists (remains) in the cylinder chamber or reservoir, this air will cause a decrease in damping force and a decrease in the spring constant. It is necessary to exclude air, and for this purpose, the bleeder valve 13 is provided above the reservoir of the suspension, as shown in FIG.

"Problems to be Solved by the Invention" However, in the conventional suspension as described above, although it is easy to eliminate the air present in the reservoir 3, the air inside the cylinder, especially in the upper chamber 16 of the piston. Although it is possible to eliminate the air in the spaces 17 and 18 of the rod guide 4 to the outside by repeatedly moving the rod 7 up and down, it is extremely difficult to sufficiently eliminate this air.

An object of the present invention is to provide a hydraulic shock absorber that solves the above-mentioned problems of conventional shock absorbers.

"Means for Solving the Problems" The present invention has the following configuration in order to achieve the above object. That is, a reservoir is formed between the inner cylinder and the outer cylinder of a double cylinder consisting of an inner cylinder and an outer cylinder, and the reservoir is slidably inserted into a rod guide and a seal member provided at the upper part of the inner cylinder and the reservoir. In the hydraulic shock absorber, a piston is slidably attached to the inner cylinder on a rod, and a damping force generation mechanism is provided in the inner cylinder. A bleeder valve is connected to the upper part of the inner cylinder.

"Function" Damping valves 10a and 10 are used during the contraction process and extension process, respectively.
b opens to generate damping force.

When pressure oil is supplied to the hydraulic shock absorber and when the hydraulic shock absorber is operated, the air present in the reservoir is discharged into the atmosphere by opening a check valve, passing through the upper part of the cylinder, and opening a bleeder valve. Furthermore, the air present in the piston upper chamber and its upper part is discharged into the atmosphere via the upper part of the cylinder by opening the bleeder valve.

Note that since a check valve is provided at the top of the reservoir, air will not flow into the reservoir from the top of the inner cylinder.

Therefore, when filling the cylinder with pressure oil and operating the hydraulic shock absorber, the air in the upper part of the inner cylinder and inside the rehearsal chamber is discharged to the atmosphere, resulting in a decrease in damping force and a decrease in the damping constant during operation. prevent.

"Example" An embodiment of the present invention will be described below with reference to FIG.

In this embodiment, the same parts as in the conventional example are given the same reference numerals, and the explanation thereof will be omitted.

Reference numeral 21 in FIG. 1 is a rod guide, and a ring-shaped protrusion 22 that is brought into contact with the seal member 5 is provided on the surface of the rod guide 21 facing the seal member 5. In addition, a step 23 is provided on the end surface of the rod guide 21 on the reservoir 3 side.
．． 24 is formed.

Further, a communication groove 26 is formed on the outer circumference of the rod guide 21 to communicate the space 25 formed between the protrusion 22 and the inner circumferential surface of the outer cylinder 2 with the reservoir 3. A slit 27 is formed to communicate the space 18 between the seal member 5 and the space 25.

A check valve 28 is provided at the upper end of the reservoir 3 so as to tightly fit around the outer periphery of the step 23 of the rod guide 21 and abut against the step 24 . The check valve 28 is a one-way valve that prevents fluid from flowing from the space 25 to the reservoir 3 and allows fluid to flow from the reservoir 3 to the space 25.

On the other hand, a rod guide 21 and a block 29 are fixed to the outer circumference of the outer cylinder 2 so as to be located outside of the seal member 5. A bleeder valve 13 is attached to this block 29. This bleeder valve I3 is connected to the outer cylinder 2.
It communicates with the space 25 through a hole 30 formed in the outer circumferential wall of.

Then, pressure oil is filled into the inner cylinder l through the passage 14 of the rod 7 from a pressure oil supply source such as a pump or an accumulator.

At this time and when the hydraulic shock absorber of this embodiment is in operation, the air present in the reservoir 3 opens the check valve 28 and passes through the communication groove 26 into the space 25. The bleeder valve 13 is opened and the liquid is discharged into the atmosphere via the hole 3o.

Moreover, the air existing in the piston upper chamber 16 is
The air flowing into the slit 27.18 and present in the space 17.18 flows into the slit 27.18. Space 25. Bleeder valve 13 via hole 30
is opened and discharged into the atmosphere.

Note that since the check valve 28 is provided at the upper part of the reservoir 3, air in the space 25 will not flow into the reservoir 3.

Further, during the contraction process and the expansion process of the hydraulic shock absorber of this embodiment, the damping valves 10a and tpb open, respectively, to generate a damping force.

Therefore, according to this embodiment, when filling the cylinder with pressure oil and when operating the hydraulic shock absorber, the two pistons 16
．． Since the air in the spaces 17, 18, 25 and the reservoir 3 is discharged to the atmosphere, it is possible to prevent a decrease in the damping force and a decrease in the damping constant when the hydraulic shock absorber is activated.

In addition, in the above-mentioned Examples, the present invention was described as Hydro-2,
- Although applied to Matic The Suspension, the present invention is not limited thereto, and can also be applied to general hydraulic shock absorbers.

[Effects of the Invention] According to the present invention, in a hydraulic shock absorber consisting of a double cylinder of an inner cylinder and an outer cylinder in which a damping force generation mechanism is provided in the inner cylinder, the upper part of the reservoir between the inner and outer cylinders is prevented from returning. The inner cylinder is communicated with the upper part of the inner cylinder through the valve, and the bleeder valve is communicated with the upper part of the inner cylinder, so that when filling the cylinder with pressure oil and operating the hydraulic shock absorber, the two pistons, the rod and Space between the rod guide.

The air in the space between the rod guide and the seal member and in the reservoir can be quickly discharged to the atmosphere, thereby preventing a decrease in damping force or a decrease in the damping constant when the hydraulic shock absorber is activated. can.

[Brief explanation of the drawing]

FIG. 1 is a partially omitted longitudinal cross-sectional view showing an embodiment of the present invention, and FIG. 2 is a partially omitted longitudinal cross-sectional view of a conventional hydro-pneumatic suspension. 1...Inner cylinder, 2...Outer cylinder, 3...
... Reservoir, 4 ... Rod guide, 5 ... Seal member, 7 ... Rod, 8 ... Piston, 10
a, 10b - damping valve (damping force generation mechanism), 13.
bleeder valve.

Claims (1)

[Claims] A reservoir is formed between the inner cylinder and the outer cylinder of a double cylinder consisting of an inner cylinder and an outer cylinder, and the rod is slidably inserted into a rod guide and a seal member provided at the upper part of the inner cylinder and the reservoir. In the hydraulic shock absorber, a piston is slidably attached to the inner cylinder, and a damping force generation mechanism is provided in the inner cylinder, and an upper part of the reservoir is communicated with an inner upper part of the inner cylinder via a check valve. A hydraulic shock absorber, characterized in that a bleeder valve is communicated with the upper part of the inner cylinder.