JPS6227724Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a bottom piece of a so-called double-tube hydraulic shock absorber having a dual structure of inner and outer cylinders.

In this type of hydraulic shock absorber, a piston equipped with a damping force generating device is slidably fitted into an inner cylinder, and the piston is fixed at one end. It operates by discharging water into the reservoir chamber or replenishing it into the inner cylinder. During the so-called pushing stroke, in which the piston advances into the inner cylinder, the piston moves downward while providing a certain amount of resistance, and conversely, during the retracting stroke, there is a non-return check at the bottom of the inner cylinder so that oil can be quickly replenished into the inner cylinder. Generally, a bottom piece with a valve structure is fitted. Therefore, the pressure inside the inner cylinder during the pushing stroke is several tens of atmospheres, so the inner cylinder receives a force that pushes it outward in the radial direction due to the hydraulic pressure inside the inner cylinder.
When used for a long time or when abnormally high internal pressure is applied, the press-fit part between the inner cylinder and the bottom piece may loosen, and in the worst case, oil may leak from this part, resulting in disturbances in the damping force during the pushing stroke. This causes a problem in which the original buffering function cannot be maintained.

The purpose of this invention is to prevent such problems, and the inner and outer cylinders 1,
In a double-tube hydraulic shock absorber in which a bottom piece 6 having an oil passage 5 communicating with an oil reservoir chamber 4 between two cylinders is press-fitted, an end face of the inner cylinder 1 protrudes outward from the press-fitted inner cylinder part 6a of the bottom piece 6. A side wall 6c is provided perpendicularly to the step portion 6b and comes into contact with the outer circumferential surface of the inner cylinder 1, and the side wall 6c and the inner cylinder press-fitting portion 6a form a It is characterized by sandwiching the inner and outer walls of the lower end.

In the drawing, the bottom piece 6 has an oil passage 5 formed in its inner cylinder press-fitted part 6a, and a first valve plate 8 that is elastically attached to the press-fitted part 6a via a spring 7 so as to close the oil passage 5. An elastic second valve plate 10 is provided to close a valve hole 9 provided in the first valve plate 8, so that the damping force can be adjusted by the bottom piece 6. A piston 11 is fitted into the inner cylinder 1, and the piston rod 12 of the piston 11 protrudes from one end cover of the shock absorber body 1 and is fixed to the case 13, and the spring seat 14 provided in the case 13 and the shock absorber body are connected to each other. A coil spring 16 is interposed between the spring seat 15 provided at 1 and the spring seat 15 provided at 1. The side wall 6c of the bottom piece 6 may be formed in an annular shape around the entire circumference of the stepped portion 6b, or may be provided in a plurality of protrusions at intervals. Since it is possible to visually check whether the tip of the cylinder is securely in contact with the upper surface of the stepped portion 6b of the bottom piece, errors in assembly can be reduced.

In this way, according to the present invention, the bottom piece 6 that is press-fitted into the bottom surface of the inner cylinder 1 is formed with a stepped part 6b that projects outward from the inner cylinder press-fitting part 6a and comes into contact with the end surface of the inner cylinder 1, A side wall 6c is provided which is perpendicular to the stepped portion 6b and abuts on the outer circumferential surface of the inner cylinder 1.
Since the inner and outer walls of the lower end of the inner cylinder 1 are sandwiched between the press-fitting part 6a of the bottom piece 6 and the press-fitting part 6a of the inner cylinder 1, the end surface of the inner cylinder 1 is held between the press-fitting part 6a of the bottom piece 6 and the side wall. Since the bottom piece 6c is not held between the bottom piece 6c and pushed apart in the radial direction
This has the effect of preventing oil from leaking from the press-fit portion 6a and maintaining the buffering function over a long period of time.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention, and FIG. 1 is a partially cutaway front view, and FIG. 2 is an enlarged sectional view of the main part. 1...Inner cylinder, 2...Outer cylinder, 3...Buffer body,
4...Oil reservoir chamber, 5...Oil passage, 6...Bottom piece, 6a...Inner cylinder fitting part, 6b...Step part, 6c
...side wall.

Claims (1)

[Scope of utility model registration request] An oil reservoir chamber 4 between the inner and outer cylinders 1 and 2 is provided on the bottom surface of the inner cylinder 1 of the shock absorber main body 3 in which the inner cylinder 1 and the outer cylinder 2 are coaxially fitted.
In a double-tube hydraulic shock absorber in which a bottom piece 6 having an oil passage 5 communicating with the bottom piece 6 is press-fitted, the bottom piece 6
A step part 6b is formed which protrudes outward from the inner cylinder press-fitting part 6a and comes into contact with the end surface of the inner cylinder 1, and a side wall 6c which is perpendicular to the step part 6b and comes into contact with the outer peripheral surface of the inner cylinder 1. A bottom piece of a double-tube hydraulic shock absorber, characterized in that the inner and outer walls of the lower end of the inner cylinder 1 are sandwiched between the side wall 6c and the inner cylinder press-fitting part 6a.