JPH09105437A - Shock absorber - Google Patents

Abstract

PROBLEM TO BE SOLVED: To ensure a volume between an outer shell and a cylinder, for example, the volume of a reservoir chamber, at a high value and besides to press a pipe for reinforcement in the lower part of the outer shell with high precision. SOLUTION: An outer shell is arranged at the outside of a cylinder 1, and an outside reinforcement pipe 15 is pressed in the outer periphery of an outer shell 6A. A knuckle bracket is pressed in externally of the outside reinforcement pipe and the lower parts of the outer shell, the outside reinforcement pipe, and the knuckle bracket are welded together.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shock absorber which is interposed between a vehicle body and an axle of a vehicle such as a four-wheeled vehicle to damp vibrations from a road surface.

[0002]

2. Description of the Related Art Between a vehicle body and an axle of a four-wheeled vehicle, the transmission of vibrations to the vehicle body side is eased even if the traveling conditions or the condition of the road surface change, so that stable traveling is possible. Shock absorbers are suspended. An example of such a shock absorber is shown in FIG. To explain this, 1 is cylinder, 2 is
A piston with a damping force generating mechanism that divides the inside of the cylinder 1 into a rod-side chamber 3 and a piston-side chamber 4 is a piston rod, and 6 is a reservoir chamber 7 that covers the outside of the cylinder 1.
Is a base valve for applying a damping force to the hydraulic oil flowing between the reservoir chamber 7 and the piston side chamber 4, and 9 is a rod guide portion for connecting the upper ends of the rod side chamber 3 and the reservoir chamber 7 to each other. Block and piston rod 5
Is held in the cylinder 1 in an airtight manner so that it can freely move in and out. 10
Is a lower cap provided at the end of the cylinder 1 so as to enclose the base valve 8. Reference numeral 11 is a knuckle bracket that supports the outer periphery of the end of the outer shell 6 and is attached to the axle side, together with the cylinder 1 and the lower cap 10.
And are integrally connected at the lower weld portion 12. 13 is
The spring guide, 14 is a seam weld. In addition, the outer shell 6 includes the knuckle bracket 11
In order to obtain a sufficient mounting strength for the portion corresponding to, the seam welded portion 14 side is thin, but the lower welded portion 12 side is formed sufficiently thick, and as a whole, as a tapered pipe, the outer shell We are trying to reduce the weight of.

[0003] In such a shock absorber,
When the piston rod 5 is extended, the rod side chamber 3
Hydraulic fluid flows to the piston side chamber 4 via the damping force generation mechanism on the piston 2, and at this time, an extension side damping force is generated.
On the other hand, during the pressure stroke, the hydraulic oil in the piston side chamber 4 flows into the rod side chamber 3 via the damping force generating mechanism, and generates the compression side damping force. At this time, between the piston side chamber 4 and the reservoir chamber 7, the hydraulic oil at the time of each stroke operation is moved back and forth via the base valve 10.

Since the conventional shock absorber is constructed as described above, it is necessary to manufacture the outer shell 6 as a tapered pipe as described above, or as a stepped pipe if necessary, by drawing or the like. For this reason, it is necessary to use a mold die and a plug, which requires a large amount of equipment and power, requires a large amount of equipment investment, and has a problem that the processing time is long and the processing cost is high.

Therefore, a shock absorber as disclosed in Japanese Utility Model Laid-Open No. 4-966637 has been developed, and by using a thin pipe having a constant plate thickness as the outer shell, a desired strength can be obtained while the processing cost is low, and , Can be mass-produced efficiently.

As shown in FIG. 4, this shock absorber has a piston 2 with a damping force generating mechanism that divides the interior of the cylinder 1 into a rod-side chamber 3 and a piston-side chamber 4, and the piston 2 is attached to the inside of the cylinder 1. Piston rod 5 that is inserted into and removed from the cylinder 1, a base valve 8 provided at the open end of the piston side chamber 4 of the cylinder 1, and the cylinder 1
And an outer shell 6A that forms the reservoir chamber 7 by wrapping the outside of the
The outer periphery of the outer shell 6A is supported by a knuckle bracket 11, and the bottomed cylindrical body 10A is fitted to the inner periphery of the outer shell 6A so as to wrap the cylinder end. The outer shell 6A and the knuckle bracket It is welded together with 11.

According to this shock absorber, the bottomed cylindrical body 10A also serves as a conventional lower cap for sealing the working oil in the cylinder 1, and is fitted into the inner circumference of the end of the outer shell 6A to provide the knuckle bracket 11 Since it is also welded to the outer shell 6A, there is an effect that the outer shell end of the portion corresponding to the outer shell 6A is reinforced, and this reinforcement can be implemented easily and at low cost with a simple configuration.

[0008]

However, although the newly developed shock absorber shown in FIG. 4 does not have a special defect in use, it does not have the following problems. That is, when the bottomed cylindrical body 10a is press-fitted inside the outer shell 6A, the volume of the volume reservoir chamber 7 is regulated.

The outer peripheral surface of the bottomed cylindrical body 10A can be accurately and smoothly finished by drawing or the like. However, since the outer shell 6A is an electric resistance welded pipe, it is difficult to form the inner peripheral surface of the outer shell 6A accurately and smoothly. , Therefore outer shell 6A
It may be difficult to press-fit the bottomed cylindrical body 10A into the inner periphery of the cylinder with high accuracy, and it is difficult to manage the pressure.

Therefore, an object of the present invention is to provide a shock absorber which can secure a large volume between the outer shell and the cylinder, for example, the volume of the reservoir chamber, and can press a reinforcing pipe into the lower portion of the outer shell with high precision. It is to be.

[0011]

In order to achieve the above object, the structure of the present invention is such that a piston having a damping force generating mechanism that divides the inside of a cylinder into a rod side chamber and a piston side chamber, and the piston is attached. A piston rod that is inserted into and removed from the cylinder, a base valve that is provided at the open end of the piston side chamber of the cylinder, an outer shell that wraps the outside of the cylinder to form a reservoir chamber and is formed with a constant thickness over the entire length. In a shock absorber consisting of, an outer reinforcement pipe press-fitted to the outer periphery of the end portion of the outer shell, and a knuckle bracket press-fitted to the outer periphery of the reinforcement pipe, the lower end of the outer shell, the lower end of the outer reinforcement pipe, and the lower end of the knuckle bracket. Is welded.

In this case, a row cap may be provided in the lower portion of the outer shell, and the lower end of the outer shell, the lower end of the outer reinforcing pipe, the lower end of the knuckle bracket, and the outer periphery of the lower cap may be welded together.

Further, the lower part of the outer shell is formed by drawing to have a smaller diameter than the upper part, and the upper part of the reinforcing pipe is extended along the outer periphery of the outer shell to a position higher than the drawing starting point between the upper part and the lower part of the outer shell. May be extended.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows one embodiment of the present invention.

The basic structure of this shock absorber is the same as that of the conventional shock absorber shown in FIG. 4, and includes a piston 2 with a damping force generating mechanism that divides the inside of the cylinder 1 into a rod side chamber 3 and a piston side chamber 4, A piston rod 5 attached to and withdrawn from the cylinder 1 with the piston 2 attached, a base valve 8 provided at the open end of the piston side chamber 3 of the cylinder 1, and a reservoir chamber 7 wrapping the outside of the cylinder 1 are formed. And an outer shell 6A having a constant thickness over the entire length.

Further, the shock absorber is provided with an outer reinforcing pipe 15 press-fitted into the outer periphery of the lower end portion of the outer shell 6A and a knuckle bracket 11 press-fitted into the outer periphery of the reinforcing pipe 15 and serves as the lower end of the outer shell 6A. The lower outer periphery, the lower lower end of the outer reinforcing pipe 15 and the lower lower end of the knuckle bracket 11 are joined by welding 16. The welding position may be the outer periphery of the lower portion slightly above this rather than the lower portion.

In the shock absorber having such a configuration, as described in the above-mentioned prior art, the desired damping force generating action is exhibited during the extension stroke and the compression stroke of the piston rod 5, respectively. Also, in this shock absorber, the outer shell 6A is thin over the entire length,
Although the strength of the knuckle bracket 11 is significantly reduced at the mounting portion, the outer reinforcing pipe 15 is press-fitted onto the outer peripheral surface side of the end of the outer shell 6A, and this is joined to the outer shell 6A and the knuckle bracket 11 by welding. By doing so, the strength can be made sufficiently large. Therefore, the outer shell 6A is firmly attached to the knuckle bracket 11 while being reinforced by the outer reinforcing pipe 15. Further, since the outer shell 6A is made of a thin tubular body, it is lightweight and easily obtained at a low cost. Therefore, without preparing expensive equipment,
By using the current inexpensive welding equipment, the efficiency of shock absorber assembly can be improved, and the quality is reliable.

FIG. 2 shows another embodiment of the present invention, which is substantially the same as the embodiment of FIG.

In this embodiment, the lower inner peripheral niloar cap 17 of the outer shell 6A is coupled to the lower end of the outer shell 6A, the lower end of the outer reinforcing pipe 15, the lower end of the knuckle bracket 11, and the outer periphery of the lower cap 17. Are integrally joined by welding 16, and the action and effect are
This is the same as the embodiment of FIG.

Further, FIG. 3 shows a shock absorber according to another embodiment of the present invention. This is a modification of the shock absorber according to the embodiment of FIG.

That is, this shock absorber relates to the case where an outer shell 6A having a large outer diameter is used. The outer shell 6A is formed by drawing the lower portion 6C into a smaller diameter than the upper portion 6B. There is. Then, the upper portion 15A of the reinforcing pipe 15 is extended along the outer periphery of the outer shell 6A to a position above the drawing starting point 18 which is a bent portion between the upper portion 6B and the lower portion 6C of the outer shell 6A.

When the outer shell 6A is drawn, a taper portion 19 is formed between the upper portion 6B and the lower portion 6C, so that the upper portion 15A of the reinforcing pipe 15 also tapers along the outer periphery of the outer shell 6A. The part 20 is formed. In the above-described embodiment, the drawing processing starting portion 18
Since the upper portion 15A of the reinforcing pipe 15 extends further upward, concentrated stress can be dispersed in the drawing starting point portion 18 and the strength can be increased. Further, even if the outer shell 6A having a large diameter is used, since the lower portion 6B is drawn to a small diameter, the reinforcing pipe 15 and the knuckle bracket 11 having the same outer diameter shown in FIG. 2 can be used, and the common parts can be used. It has excellent processability and economic efficiency. Other configurations, functions and effects are the same as those of the shock absorber shown in FIGS.

[0023]

According to the invention of each claim, there are the following effects.

Although the overall thickness is reduced by using a thin cylindrical body as the outer shell, the strength of the knuckle bracket portion can be maintained at a sufficient size, so that the shock absorber can be assembled efficiently. There is an effect that a good, simple, and low-cost product can be obtained.

Since the outer reinforcing pipe is press-fitted to the outer periphery of the outer shell and the knuckle bracket is press-fitted to the outer periphery of the outer pipe, the outer shell and the outer reinforcing pipe are press-fitted with high precision, and the press-fitting is easily controlled. That is, the outer peripheral surface of the outer shell is originally machined smoothly and accurately, and since the outer reinforcing pipe is short, the inner peripheral surface of the outer reinforcing pipe can be machined smoothly and accurately, and two members with high accuracy are press-fitted. Therefore, the press-fitting accuracy is good and the press-fitting work becomes easy.

Since the outer pipe can be press-fitted into the outer shell while the knuckle bracket is press-fitted into the outer pipe, the press-fitting work can be speeded up.

[Brief description of the drawings]

FIG. 1 is a partially cutaway sectional view of a shock absorber according to an embodiment of the present invention.

FIG. 2 is a partially cutaway sectional view of a shock absorber according to another embodiment.

FIG. 3 is a partially cutaway sectional view of a shock absorber according to still another embodiment.

FIG. 4 is a sectional view of a conventional shock absorber.

FIG. 5 is a sectional view of a conventional shock absorber.

[Explanation of symbols]

 1 Cylinder 2 Piston 3 Rod Side Chamber 4 Piston Side Chamber 5 Piston Rod 6A Outer Shell 7 Reservoir Chamber 8 Base Valve 11 Knuckle Bracket 15 Reinforcement Pipe 15A Reinforcement Pipe Top 16 Welding 17 Lower Cap 18 Throttle Starting Point 19,20 Taper Section

Claims (3)

[Claims] 1. A piston having a damping force generating mechanism that divides the inside of a cylinder into a rod side chamber and a piston side chamber, a piston rod that is mounted in and out of the cylinder, and an open end of the piston side chamber of the cylinder. In a shock absorber consisting of a base valve provided in the outer cylinder and an outer shell that wraps the outside of the cylinder to form a reservoir chamber and has a constant wall thickness over the entire length, an outer reinforcement that is press-fitted to the outer periphery of the end of the outer shell. A shock absorber comprising a pipe and a knuckle bracket press-fitted to the outer periphery of the reinforcing pipe, wherein the lower end of the outer shell, the lower end of the outer reinforcing pipe, and the lower end of the knuckle bracket are welded. 2. A lower cap is connected to the inner periphery of the lower portion of the outer shell, and the lower end of the outer shell, the lower end of the outer reinforcing pipe, the lower end of the knuckle bracket, and the outer periphery of the lower cap are welded together. The shock absorber according to claim 1. 3. A lower part of the outer shell is formed to have a smaller diameter than the upper part by drawing, and the upper part of the reinforcing pipe extends along the outer periphery of the outer shell up to a position higher than a drawing starting point between the upper part and the lower part of the outer shell. The shock absorber according to claim 1 or 2, wherein the shock absorber is extended.