JP2000027926A - Shock absorber - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a shock absorber to improve durability and regulate the rise of a piston and a piston rod slidably in a cylinder through simple constitution as the generation of impact noise is efficiently suppressed. SOLUTION: A shock absorber comprises a cylinder 10; a piston 20 assembled on the inner peripheral surface of the cylinder 10 in a liquidtight manner and axially; and a piston rod 30 at the lower end part of which the piston 20 is fixed. An annular stopper 31 formed of a buffering material is fixed in the cylinder 10 and on the outer peripheral surface of the intermediate part of the piston rod 30. A plurality of leaf springs 41 are arranged at the inner upper end part of the cylinder 10. The leaf springs 41 are formed in an annular shape and a waveform and vertically laminated with the piston rod 30 extending therethrough. Further, an elastic member 42 is interposed between a part of the leaf springs 41 adjacent to each other.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the vibration of an object elastically supported by a support, for example, to generate a damping force provided between a wheel and a vehicle body to suppress the vibration of the vehicle body. The present invention relates to a shock absorber that generates a damping force for suppressing.

[0002]

2. Description of the Related Art Conventionally, this type of device has a cylinder divided into upper and lower chambers by a piston which is filled with hydraulic fluid and is slidably and axially slidable, and a lower end of the piston. And a piston rod whose upper end is projected from the upper end surface of the cylinder so as to be able to advance and retreat. In this case, a stopper is fixed on the outer peripheral surface of the intermediate part of the piston rod in the cylinder, and a coil spring is disposed at the upper end of the cylinder. The piston and the piston rod are brought into contact with the cylinder by the contact between the stopper and the coil spring. In some cases, the rise has been elastically damped to regulate the impact sound while suppressing it.

Further, as shown in, for example, Japanese Utility Model Application Laid-Open No. 56-127438, a stopper constituted by a cylindrical elastic member is fixed on the outer peripheral surface of the intermediate portion of the piston rod at the upper end of the cylinder. The abutment between the stopper and the upper end of the cylinder elastically cushions the rise of the piston and piston rod, thereby suppressing and controlling the impact sound. The stopper is provided with an opening and an annular groove to provide a spring constant of the stopper. (Ratio of load generated to shrinkage)
Has been configured to vary according to the amount of shrinkage, that is, the spring characteristics of the stopper are set to be non-linear to improve the buffering efficiency. Also, as shown in, for example, Japanese Utility Model Laid-Open No. 4-107193, it is well known that a motorcycle suspension device in which a coil spring is constituted by a plurality of portions having different winding densities and set to a non-linear spring characteristic is used. Have been.

[0004]

However, in the conventional apparatus in which the coil spring is disposed in the above-mentioned cylinder, the stopper has a small area in contact with the lower end of the coil spring, and a large impact is applied to the stopper. However, there is a problem that the durability is low. On the other hand, in the conventional device employing the stopper formed by the elastic member, the opening and the annular groove for obtaining appropriate nonlinear spring characteristics need to be formed in the stopper, so that the configuration is complicated. Was. On the other hand, as in the case of the conventional motorcycle suspension device, a coil spring having a non-linear spring characteristic may be constituted by a plurality of portions having different winding densities, and the coil spring may improve the buffering efficiency. However, in this case, it is difficult to change the winding density of the coil spring halfway, and it is difficult to obtain an appropriate nonlinear spring characteristic.

[0005]

SUMMARY OF THE INVENTION The present invention has been made to address the above problems, and has as its object the purpose of having a highly durable, simple structure, and effectively suppressing the impact noise while controlling the piston and piston rod relative to the cylinder. It is to provide a shock absorber for controlling the rise.

The structural features of the present invention for achieving the above object include a stopper fixed on the outer peripheral surface of the intermediate portion of the piston rod in the cylinder, and a piston rod formed in an annular and corrugated shape. A plurality of leaf springs laminated at the upper end of the cylinder are provided so as to penetrate, and the stopper and the lowermost leaf spring of the plurality of leaf springs abut against the cylinder to restrict the rise of the piston and the piston rod. That is to do. According to this, since the leaf spring is formed in a waveform, the entire lower surface of the lowermost leaf spring comes into contact with the stopper, and the convex portion of the leaf spring that comes into contact with the stopper has a curved surface. Therefore, the impact force applied to the stopper is dispersed, so that the durability of the stopper is kept high, and the rise of the piston and the piston rod is elastically damped and restricted while suppressing the impact sound. be able to.

Another feature of the present invention is that the stopper is made of a cushioning material in the shock absorber having the above-mentioned features. According to this, the rise of the piston and the piston rod can be more efficiently buffered and restricted while suppressing the impact noise. Further, in this case, since the impact force applied to the stopper is dispersed as described above, it is possible to maintain the durability of the stopper high and set the hardness of the cushioning material constituting the stopper low. It is possible to more efficiently buffer the rise of the piston and the piston rod, and to control the impact while suppressing the impact noise.

Another structural feature of the present invention resides in that in the shock absorber having the above-described feature, at least one of the plurality of leaf springs is formed to have a different thickness from the other. According to this, since the spring constant of each leaf spring differs according to its wall thickness, the spring characteristics of the plurality of leaf springs are set nonlinearly. That is, the spring characteristics of the entire leaf spring can be set to appropriate nonlinear characteristics only by the combination of the thicknesses of the leaf springs, so that the piston and the piston rod can be more efficiently raised with a simple configuration. It is possible to regulate while suppressing the impact sound.

Another feature of the present invention is that in the shock absorber having the above feature, an elastic member is interposed between at least a part of adjacent leaf springs among a plurality of leaf springs. It is in. According to this, the spring characteristics of the plurality of leaf springs are set to more appropriate non-linear characteristics by adding the spring characteristics of the elastic member, the rise of the piston and the piston rod is more efficiently buffered, and the impact noise is reduced. It is possible to control while suppressing, and it is also possible to suppress the interference sound between the leaf springs.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a cross-sectional view illustrating an entire shock absorber according to the embodiment applied to a vehicle.
This shock absorber includes a cylinder 10, a piston 20 mounted on the inner peripheral surface of the cylinder 10 in a liquid-tight and slidable manner in the axial direction, and a piston rod 30 having the piston 20 fixed at a lower end portion. I have.

The cylinder 10 includes an outer cylinder 11 and an inner cylinder 12 which are both formed in a cylindrical shape and arranged coaxially. The outer cylinder 11 is mounted on a carrier CR as a unsprung member at a lower end side wall. The inner cylinder 12 is connected to the outer cylinder 11 via an annular support member 13 at its upper end.
Liquid-tightly supported on the inner peripheral surface of the upper end of the
The lower end is supported on the inner peripheral surface of the lower end of the outer cylinder 11 via the support member 14. The lower end of the cylindrical support member 15 is coaxially intruded and fixed to the upper end of the inner cylinder 12.

The interior of the inner cylinder 12 is partitioned by a piston 20 into upper and lower chambers R1 and R2. Upper and lower chamber R1,
R2 is filled with hydraulic oil (hydraulic fluid), and the lower chamber R2 communicates via a support member 14 with an annular chamber R3 formed between the outer cylinder 11 and the inner cylinder 12. The annular chamber R3 is filled with gas, and absorbs a change in volume of hydraulic oil in the upper and lower chambers R1 and R2 due to the advance and retreat of the piston rod 30.

The piston 20 is provided with an orifice (not shown) for communicating the upper and lower chambers R1 and R2, and a damping force is generated by the orifice as the piston rod 30 moves up and down. The piston rod 30 is formed in a cylindrical and long shape, and has an upper end protruding from the upper end surface of the cylinder 10 so as to be able to advance and retreat, and is assembled to the vehicle body BD as a sprung member at the upper end.

In the cylinder 10, the piston rod 3
An annular stopper 31 formed of a cushioning material made of an elastic material such as rubber or synthetic resin is fixed on the outer peripheral surface of the intermediate portion 0 by a bracket 32. As shown in detail in FIG. 2, a plurality of (14 in this embodiment) leaf springs 41 are provided at the upper end inside the cylinder 10. As shown in detail in FIG. 3, the leaf springs 41 are formed in an annular and corrugated shape. The leaf springs 41 are vertically stacked while penetrating the piston rod 30 and bonding the projections of the adjacent leaf springs 41 to each other. ing. The uppermost leaf spring 41 is fixed to the lower surface of the support member 13 at the upper surface.

A part of the leaf spring 41 (six pieces from the uppermost layer in this embodiment) is formed to have a large thickness and their spring constant is set high, and the other part is formed to have a small thickness. Thus, their spring constants are set low. In addition, a part (in this embodiment, 5
An elastic member 42 made of, for example, rubber, synthetic resin, or the like is interposed between the adjacent leaf springs 41.
Due to the mixture of the different spring constants and the interposition of the elastic member 42, the spring constant of the plurality of leaf springs 41 changes according to the amount of contraction as shown in detail in FIG. That is, the spring characteristics of the entire leaf spring 41 are set to be non-linear. In this case, when the contraction amount of the whole leaf spring 41 is small, the spring constant is small, that is, the load generated with respect to the contraction amount is small, in other words, the contraction of the leaf spring 41 is easy. When the amount of contraction is large, the spring constant is large, that is, the load generated with respect to the amount of contraction is large, in other words, it is difficult to contract with respect to the load.

In the shock absorber configured as described above, when the vehicle body BD moves up and down, the piston 20 and the piston rod 30 move up and down with respect to the cylinder.
A damping force is applied to the vertical movement by the orifice of the piston 20. In this case, when the vehicle body BD rises with respect to the carrier CR, that is, when the piston 20 and the piston rod 30 rise with respect to the cylinder 10, the stopper 31 and the lower surface of the leaf spring 41 of the lowermost layer make the same rise. Is regulated.

In this case, since the leaf spring 41 is formed in a waveform, the entire lower surface of the lowermost leaf spring 41 abuts against the stopper 31, and furthermore, the convex portion of the leaf spring 41 abuts against the stopper 31. Becomes a curved surface. Therefore, the stopper 3
Since the impact force applied to the piston 1 is dispersed, the durability of the stopper 31 is kept high, and the rise of the piston 20 and the piston rod 30 is elastically buffered, so that the impact noise is suppressed and suppressed.

Further, since the stopper 31 is made of a cushioning material made of an elastic material, the rise of the piston 20 and the piston rod 30 is more efficiently buffered and the impact noise is suppressed while being suppressed. ing. Further, in this case, since the impact force applied to the stopper 31 is dispersed as described above, the hardness of the cushioning material forming the stopper 31 is set low while maintaining the durability of the stopper 31 high. It is possible to more efficiently buffer the rise of the piston 20 and the piston rod 30 and to restrict the impact while suppressing the impact noise.

The spring characteristics of the plurality of leaf springs 41 are set to be non-linear. When the amount of contraction of the entire leaf spring 41 is small, it is easy to contract against a load, and when the amount of contraction of the whole leaf spring 41 is large, the load is On the other hand, since the piston 20 and the piston rod 30 are less likely to shrink, the rise of the piston 20 and the piston rod 30 is more efficiently buffered, and the impact noise is suppressed while being suppressed. In this case, the leaf spring 41
The entire spring characteristic can be set to an appropriate nonlinear characteristic only by a combination of the thickness of each leaf spring 41. In the above embodiment, two types of leaf springs 41 having a large thickness are used.
Are disposed in the upper layer portion and the lower layer portion. However, depending on the necessity and application, leaf springs 41 having further different thicknesses may be employed, and the number and arrangement positions of the leaf springs 41 having different thicknesses may be set differently. By doing so, it is also possible to set the spring characteristics of the entire leaf spring 41 to more appropriate nonlinear characteristics. Therefore, with a simple configuration, it is possible to more efficiently buffer the rise of the piston 20 and the piston rod 30 and to restrict the impact while suppressing the impact noise.

Further, since the elastic member 42 is interposed between some adjacent leaf springs 41 of the plurality of leaf springs 41, the spring constant of the elastic member 42 is added and the plurality of leaf springs 41 are added. The spring characteristics of the entire piston 41 and the piston rod 30 are set to more appropriate nonlinear characteristics.
Rise is more efficiently buffered and the impact sound is suppressed while being suppressed, and the interference sound between the leaf springs 41 is also suppressed. Note that the elastic member 42 may be interposed between all adjacent leaf springs 41 of the plurality of leaf springs 41 or may be omitted and not provided at all, depending on necessity and application. .

[Brief description of the drawings]

FIG. 1 is an overall partial cutaway view of a shock absorber according to one embodiment of the present invention.

FIG. 2 is an enlarged view of an upper portion of the inner cylinder of FIG.

FIG. 3 is a perspective view of the leaf spring of FIGS.

FIG. 4 is a graph showing spring characteristics of the whole leaf spring of FIGS.

[Explanation of symbols]

10: cylinder, 20: piston, 30: piston rod, 31: stopper, 41: leaf spring, 42: elastic member.

Claims (4)

[Claims] 1. A cylinder partitioned into upper and lower chambers by a piston in which a hydraulic fluid is sealed and which is incorporated in a liquid-tight and axially slidable manner, wherein said piston is fixed at a lower end and an upper end is fixed. A shock absorber comprising a piston rod protruding from the upper end surface of the cylinder so as to be able to advance and retreat, a stopper fixed on an outer peripheral surface of an intermediate portion of the piston rod within the cylinder, and a ring-shaped and waveform-shaped stopper. A plurality of leaf springs stacked on the upper end portion of the cylinder through the piston rod, and the stopper is brought into contact with a lowermost leaf spring of the plurality of leaf springs to provide the A shock absorber for restricting a rise of the piston and the piston rod with respect to a cylinder. 2. The shock absorber according to claim 1, wherein said stopper is made of a cushioning material. 3. The shock absorber according to claim 1, wherein at least one of the plurality of leaf springs is formed to have a different thickness from the other. 4. The shock absorber according to claim 1, wherein an elastic member is interposed between at least a part of adjacent leaf springs of the plurality of leaf springs. Shock absorber characterized by having made it.