JP3199289B2 - Hydraulic shock absorber damper - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a damper for a hydraulic shock absorber provided in a hydraulic shock absorber, and more particularly, to a structure for shutting off oil pressure at the time of oil lock, and requires a high degree of machining and assembly precision. The present invention relates to a damper for a hydraulic shock absorber that can ensure the slidability and liquid tightness of each sliding portion without any problem.

[0002]

2. Description of the Related Art FIG. 4 is a longitudinal sectional view of a main part of a conventional hydraulic shock absorber. The conventional hydraulic shock absorber 51 includes a slidable inner and outer cylinder 5.
2a and 52b, and a damper 53 inside the upper and lower end members of the telescopic cylinder 52, which acts on the upper and lower ends of the telescopic cylinder 52 to apply a damping force. A piston rod 55 to be connected and a rod guide portion 56 for moving the piston rod 55 forward and backward.
a at the end thereof, and the rod guide portion 56a of the damper cylinder 56 is fitted around the piston rod 55 when the hydraulic shock absorber 51 is most compressed, and is disposed around the piston rod 55. A damper 53 of a hydraulic shock absorber 51 provided with a cylindrical oil lock fitting portion 56b constituting an oil lock chamber A is known.

[0003]

However, when the hydraulic shock absorber 51 is most compressed, the high-pressure hydraulic oil is supplied from the oil lock chamber A formed by the oil lock fitting portion 56b of the damper cylinder 56 to the rod of the damper cylinder 56. By acting on the guide portion 56a, high pressure acts on the seal portions 56c and 56d of the rod guide portion 56a and the seal portion 54a of the piston 54, which may shorten the seal life. So that the rod guide 5
It is necessary to provide a defining member 57 for blocking the oil flow in the direction of 6a between the oil lock fitting portion 56b and the rod guide portion 56a so as to be slidable with respect to the piston rod.

However, the piston 54 and the rod guide 5
The piston rod 55, which is supported at two points by the two sliding portions 6a and 6a, further has
Since each sliding part is supported by the sliding parts, it is necessary to process and assemble all sliding supporting points concentrically in order to ensure the predetermined sliding property and liquid tightness for each sliding part. There is.

[0005] If there is eccentricity due to processing / assembly error of each sliding support point or bending of the piston rod, etc.,
If a large friction occurs on the sliding part, sometimes the sliding surface is damaged and it becomes impossible to slide, or if the liquid tightness of the sliding part is reduced due to abrasion, etc. This directly acts on the rod guide portion 56a from between the rod 55 and the defining member 57, or lowers the oil lock operation.

SUMMARY OF THE INVENTION An object of the present invention is to provide a telescopic cylinder comprising a slidable inner and outer cylinder, and a damper which is provided inside the upper and lower ends of the telescopic cylinder and exerts a damping force between both end members. Comprises a damper cylinder in which a piston that generates a damping force is slidably provided, and a piston rod that advances and retreats from a rod guide portion that forms an opening at one end of the damper cylinder and is connected to the piston. The guide portion has a cylindrical oil lock fitting portion which is fitted to the piston rod side at the time of maximum compression of the damper and constitutes an oil lock chamber around the piston rod. High processing / assembly accuracy is required after blocking the high pressure hydraulic oil in the oil lock chamber so that hydraulic oil does not act on the rod guide. And no is to ensure the sliding properties and liquid-tightness of the sliding portions.

[0007]

In order to solve the above-mentioned problems, a first aspect of the present invention comprises a telescopic cylinder having an outer cylinder attached to a vehicle body and an inner cylinder attached to an axle side, which are slidable with respect to each other. It comprises a telescopic cylinder to be fitted, a damper cylinder in which a piston generating a damping force is slidably housed, and a piston rod that advances and retreats from a rod guide portion that opens at one end of the damper cylinder, and is connected to the piston. A damper, the damper is attached to the outer cylinder, the piston rod is attached to the inner cylinder, an oil chamber is provided on the outer periphery of the damper, and an oil lock fitting portion is provided at an end of a rod guide portion of the damper cylinder. An oil lock fitting is fitted to the piston rod side to form an oil lock oil chamber with the oil lock fitting. In the hydraulic shock absorber provided with, a check valve slidably contacting the outer periphery of the piston rod is provided eccentrically in the oil lock fitting portion, and an oil chamber on the outer periphery of the damper is provided between the check valve and the rod guide portion. An internal oil chamber communicating with the oil lock case is formed, and when the check valve enters the oil lock case,
A flow of hydraulic oil from the oil lock oil chamber to the internal oil chamber is prevented, and a flow of hydraulic oil from the internal oil chamber to the oil lock oil chamber is allowed when the oil lock case is withdrawn from the oil lock case. And A second aspect of the present invention is characterized in that, in the first aspect, a sealing means for sealing the oil chamber in the damper cylinder to the oil chamber on the outer periphery of the damper cylinder is provided in the rod guide portion.

[0008]

The check valve provided on the valve holding portion of the oil lock fitting portion has a sliding portion that is eccentric to the oil lock fitting portion and slidable with respect to the piston rod. The piston rod is slidably supported by two points, a piston and a rod guide, and high-pressure hydraulic oil in the oil lock chamber is shut off by a check valve.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a longitudinal sectional view of a main part of a hydraulic shock absorber according to a first embodiment of the invention, and a longitudinal sectional view showing an oil locked state of the embodiment.

In FIG. 1, a hydraulic shock absorber 1 according to the invention is shown.
Is a telescopic cylinder 2 composed of slidable inner and outer cylinders 2a and 2b,
It comprises a damper 3 that acts on the damping force between both end members (not shown), which are located inside the telescopic cylinder 2 and constitute upper and lower ends of the telescopic cylinder 2. 2c
Is a suspension spring.

The damper 3 has a piston (not shown) that generates a damping force slidably provided therein, and is attached to the outer cylinder 2b.
A damper cylinder 5 and a piston rod 6 that moves forward and backward from a rod guide portion 5a opening at one end of the damper cylinder 5, is connected to the piston, and is attached to the inner cylinder 2a. . 3a is a rebound spring.

The rod guide portion 5 of the damper cylinder 5
a is provided with a one-way sealing means 5b which slidably holds the pressure in the damper cylinder 5 with respect to the piston rod 6, and is provided on the piston rod 6 side when the hydraulic shock absorber 1 is most compressed. Oil lock case 6 of FIG.
The cylindrical oil lock fitting portion 7 that fits and abuts on a to form an oil lock chamber protrudes.

One end of the oil lock fitting portion 7 is screw-fixed to the rod guide portion 5a to hold the sealing means 5b via a backup ring, and the other end to the valve holding portion 7c.
Make A lock valve 7a is formed on the outer periphery of the valve holding portion 7c so as to fit and abut on the piston rod 6 side to form an oil lock chamber. The lock valve 7a has a plurality of cutout grooves formed in the lower contact surface thereof, and is provided so as to be eccentric in the radial direction of the oil lock fitting portion 7. Block the flow.

Valve holding portion 7c of oil lock fitting portion 7
A check valve 7b for shutting off oil flow from the oil lock chamber formed by fitting engagement with the piston rod 6 in the direction of the rod guide portion 5a is eccentrically disposed on the inner peripheral side.

An outer peripheral side of the check valve 7b is provided with a valve holding portion 7 of an oil lock fitting portion 7 forming a valve case.
c, forming a gap as a flow path with a diameter smaller than the inner peripheral dimension, and having a plurality of cutout grooves on the holding side of the lower contact surface, and being eccentric in the range of the gap. 7c, and is urged in the valve closing direction so as to shut off the oil flow at the time of oil lock by movement in the axial direction.

On the inner peripheral side of the check valve 7b,
There is provided a sliding portion 7d formed of a guide bush that is fitted to the outer periphery of the piston rod 6 so as to be able to slide in a liquid-tight manner.

The check valve 7b has a floating structure in the radial direction.
b does not become eccentric with respect to the piston rod 6, and abnormal surface pressure of the sliding surface with the piston rod 6 is prevented. Accordingly, by determining the inner diameter of the sliding portion 7d of the check valve 7b in accordance with the outer diameter of the piston rod 6, high liquid tightness can be easily obtained.

The rod guide portion 5 of the oil lock fitting portion 7
The a side is provided with a hole 7e communicating the inside and the outside thereof. The hole 7e forms a supply path for hydraulic oil when the oil lock fitting portion 7 escapes from the oil lock state.

Also, at the time of oil lock, the hydraulic oil leaked from the minute gap between the sliding portion 7d of the check valve 7b and the outer periphery of the piston rod 6 escapes to the oil chamber on the outer periphery of the damper cylinder 5 through the hole 7e. Therefore, the hole 7e does not directly act on the sealing means 5b on the inner periphery of the rod guide portion 5a, and the hole 7e has a protective effect of the sealing means 5b.

The operation of the damper of the hydraulic shock absorber having the above configuration will be described below. In FIG. 2, when a cylindrical oil lock fitting portion 7 protruding from the rod guide portion 5a of the damper cylinder 5 fits and abuts on the oil lock case 6a on the piston rod 6 side when the hydraulic shock absorber 1 is most compressed. An oil lock chamber A is formed around the piston rod 6.

At this time, the check valve 7b eccentrically provided in the valve holding portion 7c of the oil lock fitting portion 7 is provided.
Takes a position corresponding to the piston rod 6 even when the oil lock fitting portion 7 and the piston rod 6 are eccentric, and furthermore, the lock valve 7a and the check valve 7b receive an axial force from the oil lock chamber A. By shutting off the oil pressure in the oil lock chamber A, an oil lock state is set.

The sliding portion 7d on the inner peripheral side of the check valve 7b
In this case, the high-pressure hydraulic oil in the oil lock chamber A is shut off without leaking because it is slidably fitted to the outer periphery of the piston rod 6 in a liquid-tight manner.

Next, when the hydraulic shock absorber 1 is extended and the damper cylinder 5 escapes from the oil lock state, the oil lock chamber A becomes negative pressure, and the check valve 7 is released.
b and the lock valve 7a are opened.

When the check valve 7b is opened, hydraulic oil outside the damper 3 is supplied to the oil lock chamber A through a hole 7e communicating between the inside and the outside of the oil lock fitting portion 7 on the rod guide 5a side. Similarly, when the lock valve 7a is opened, the oil lock fitting portion 7 and the oil lock case 6
The hydraulic oil outside the damper 3 is supplied from between the position a. Thereby, the damper cylinder 5 is quickly escaped from the oil lock state.

In the subsequent extension stroke, the check valve 7b provided in the oil lock fitting portion 7 is used when the oil lock fitting portion 7 and the piston rod 6 are eccentric.
Since the valve holding portion 7c is positioned at the same position as the piston rod 6, the surface pressure of the sliding surface does not increase and the increase in the sliding resistance is suppressed, so that the sliding is performed along the piston rod 6 without any trouble. . The function and effect are the same even if the lock valve 7a is configured as a fixed fitting body.

FIG. 3 is a longitudinal sectional view of a main part of a hydraulic shock absorber according to a second embodiment of the present invention. Parts similar to those of the hydraulic shock absorber are denoted by the same reference numerals.

The hydraulic shock absorber 11 is provided with an upright damper 13 in the sliding cylinder 2. The damper 13 includes a damper cylinder 5 in which a piston (not shown) that generates a damping force is slidably provided, and a piston that advances and retreats from a rod guide portion 5a that opens at one end of the damper cylinder 5 and is connected to the piston. And a rod 6. A suspension spring 2c is provided between the damper cylinder 5 provided on the inner cylinder 2a side and the outer cylinder 2b.

The rod guide 5 of the damper cylinder 5
a has a sealing means 5b made of a guide bush slidable with respect to the piston rod 6, and is fitted to an oil lock piece (not shown) on the piston rod 6 side when the hydraulic shock absorber 11 is compressed most. A cylindrical oil lock fitting portion 7 forming an oil lock chamber is projected.

The inner peripheral side of the oil lock fitting portion 7 forms a valve holding portion 7c for holding a check valve 7b which moves in the axial direction to open and close. The valve holding portion 7c includes an oil chamber 7f formed in the valve holding portion 7c from an oil lock chamber formed by fitting and contact with the piston rod 6 side.
The check valve 7b which shuts off the oil flow in the direction of is disposed eccentrically.

An outer peripheral side of the check valve 7b is provided with a valve holding portion 7 of an oil lock fitting portion 7 forming a valve case.
c to form a gap as a flow path with a smaller diameter than the inner peripheral dimension, and is held eccentrically in the valve holding portion 7c in the range of this gap, and the oil flow at the time of fitting by the axial movement. Is shut off in the valve closing direction.

On the inner peripheral side of the check valve 7b,
There is provided a sliding portion 7d formed of a guide bush that is fitted to the outer periphery of the piston rod 6 so as to be able to slide in a liquid-tight manner.

The check valve 7b has a floating structure in the radial direction.
b does not become eccentric with respect to the piston rod 6, and abnormal surface pressure of the sliding surface with the piston rod 6 is prevented. Accordingly, by determining the inner diameter of the sliding portion 7d of the check valve 7b in accordance with the outer diameter of the piston rod 6, high liquid tightness can be easily obtained.

The rod guide part 5 of the oil lock fitting part 7
The a side is provided with a hole 7e communicating the inside and the outside thereof. The hole 7e forms a supply path for hydraulic oil when the oil lock fitting portion 7 escapes from the oil lock state.

In the damper of the hydraulic shock absorber having the above-described structure, the oil lock fitting portion 7 performs an oil lock operation by the hydraulic oil held above the check valve 7b at the time of the most compression. The high-pressure hydraulic oil in the oil lock chamber is shut off by 7b.

In the extension stroke, the check valve 7b
Is opened, and the negative pressure in the oil lock chamber is supplemented through the hole 7e, whereby the oil lock is quickly released.

When the oil lock fitting portion 7 and the piston rod 6 are eccentric, the check valve 7b provided in the oil lock fitting portion takes a position corresponding to the piston rod 6 in the valve holding portion 7c. Since the surface pressure of the sliding surface does not increase and the increase in the sliding resistance is suppressed, the sliding is slid along the piston rod 6 without any trouble.

[0038]

As described above, according to the present invention, the telescopic cylinder comprises an outer cylinder mounted on the vehicle body side and an inner cylinder mounted on the axle side, and is slidably fitted to each other. A damper cylinder slidably housed with a piston that generates a damping force, and a damper comprising a piston rod that advances and retreats from a rod guide that forms an opening at one end of the damper cylinder, and that is connected to the piston.
Attach the damper to the outer cylinder and the piston rod to the inner cylinder respectively, provide an oil chamber on the outer periphery of the damper, provide an oil lock fitting at the end of the rod guide part of the damper cylinder, and fit an oil look on the piston rod side Parts are mated,
In a hydraulic shock absorber provided with an oil lock case forming an oil lock oil chamber between the oil lock fitting portion and the oil lock fitting portion, a check valve slidably contacting the outer periphery of the piston rod is provided eccentrically in the oil lock fitting portion, An internal oil chamber communicating with the oil chamber on the outer periphery of the damper is formed between the check valve and the rod guide, and the check valve is
Permissible upon entry into the oil lock case, to block the flow of hydraulic oil from the oil lock oil chamber to the inside oil chamber, at exit from the oil lock case, the flow of hydraulic fluid from the internal oil chamber to the oil lock oil chamber I did it. Therefore, the check valve provided in the oil lock fitting part enables the high-pressure hydraulic oil to be shut off during the oil lock and the oil lock to be quickly released, and the check valve is held eccentrically in the valve holding part. This ensures good slidability and liquid tightness.

Accordingly, the problem of eccentricity due to processing and assembly errors in the case of three-point sliding support is eliminated, and both good slidability and liquid tightness are ensured by simple processing and assembly.
In addition, the durability of the damper can be improved.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a main part of a hydraulic shock absorber according to a first embodiment of the invention.

FIG. 2 is a longitudinal sectional view showing an oil lock state of the embodiment.

FIG. 3 is a longitudinal sectional view of a main part of a hydraulic shock absorber according to a second embodiment of the invention.

FIG. 4 is a longitudinal sectional view of a main part of a conventional hydraulic shock absorber;

[Explanation of symbols]

1 ... hydraulic shock absorber , 2 ... telescopic cylinder , 2a ... inner cylinder, 2b
... outer cylinder, 3 ... damper , 5 ... damper cylinder , 5
a: rod guide portion , 6: piston rod , 6a: oil lock case , 7: oil lock fitting portion , 7c
... Valve holding part , 7b ... Check valve , 7d ... Sliding part , 7e ... Hole , 11 ... Hydraulic shock absorber , 13 ... Damper , A ... Oil lock chamber .

Claims (2)

(57) [Claims] 1. A telescopic cylinder comprising an outer cylinder attached to a vehicle body side and an inner cylinder attached to an axle side, which are slidably fitted to each other, and a piston which generates a damping force is slidable. A damper comprising a built-in damper cylinder, a piston rod which reciprocates from a rod guide portion forming an opening at one end side of the damper cylinder, and a piston rod connected to the piston, the damper being an outer cylinder, and the piston rod being an inner cylinder. Respectively, an oil chamber is provided on the outer periphery of the damper, an oil lock fitting portion is provided at an end of a rod guide portion of the damper cylinder, and the oil lock fitting portion is fitted on the piston rod side. In a hydraulic shock absorber provided with an oil lock case forming an oil lock oil chamber between the oil lock and the oil lock fitting portion, A check valve slidably contacting the outer periphery of the piston rod is provided eccentrically in the fitting portion, and an inner oil chamber communicating with an oil chamber on the outer periphery of the damper is formed between the check valve and the rod guide portion, the check valve, upon entry into the oil lock case, wherein the blocking the flow of hydraulic oil from the oil lock oil chamber into the inner oil chamber, when exiting from the oil lock case, the oil from the inner oil chamber A hydraulic shock absorber, which allows a flow of hydraulic oil to a lock oil chamber. 2. A hydraulic shock absorber according to claim 1, wherein said rod guide portion is provided with sealing means for sealing an oil chamber in said damper cylinder to an oil chamber on an outer periphery of said damper cylinder.