JPH0628377U - Fluid pressure type shock absorber - Google Patents

Abstract

(57) [Abstract] [Purpose] A fluid pressure type shock absorber that absorbs the kinetic energy of a load by a fluid such as hydraulic pressure. The purpose is to reduce the fluctuation of the action. A cam 51 arranged to face a plurality of holes 41 provided in the pressure tube 12 from the outer peripheral side of the pressure tube, and a cam parallel to the axis of the pressure tube for rotating the cam 51. It has a shaft 52 and a rotation operating portion 53 for rotating the cam shaft, and is configured such that the distance e between the hole and the surface of the cam is variable depending on the rotation angle position of the cam.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a fluid pressure type shock absorber that absorbs kinetic energy of a load by a fluid such as hydraulic pressure.

[0002]

[Prior art]

 Generally, in a hydraulic shock absorber, a piston moves in a pressure tube having a plurality of holes arranged along the axial direction, so that the pressure oil in the pressure tube flows out from the hole and The back pressure in the pressure tube based on the outflow resistance exerts a cushioning effect.

Further, since the magnitude of the buffering action is adjusted according to the magnitude of the kinetic energy of the load, the outflow resistance of the pressure oil from the hole can be variably adjusted. FIG. 4 is a sectional view showing an adjusting mechanism of a conventional hydraulic shock absorber 80.

In the conventional hydraulic shock absorber 80, in order to adjust the outflow resistance of the pressure oil HY, the shaft having an inner diameter substantially equal to the outer diameter of the pressure tube 81 and corresponding to the hole 82 of the pressure tube 81. The metering tubes 84 each having an orifice 85 at each of the directional positions are arranged coaxially with the pressure tube 81, and communicate with each hole 82 on the outer peripheral surface of the pressure tube 81, and the bottom portion is with respect to the outer peripheral circle. An eccentric eccentric groove 83 is formed over a central angle of about 180 degrees.

The outflow resistance in this case increases or decreases according to the viscosity length L along the arc from the point a at which the eccentric groove 83 is raised to the point b at which the orifice 85 is present, so the pressure of the metering tube 84 is reduced. The rotational angle position with respect to the tube 81 is varied to adjust the viscosity length L, and thereby the outflow resistance of the pressure oil HY is adjusted.

[0006]

However, in the above-described conventional hydraulic shock absorber 80, the outer peripheral surface of the pressure tube 81, the inner peripheral surface of the metering tube 84, the eccentric groove 83, and the like require high machining accuracy. Therefore, the manufacturing cost becomes high.

Further, since the resistance to the pressure oil HY is increased / decreased by variably adjusting the viscosity length L, it is easily affected by the fluctuation of the viscosity coefficient due to the temperature change of the pressure oil HY, and the buffering effect by the temperature change is caused. , That is, the fluctuation of the performance of the shock absorber 80 was large.

In view of the above problems, the present invention provides a fluid pressure type shock absorber in which the metering tube that requires high accuracy and precision is not required, the cost is reduced, and the fluctuation of the shock absorbing action due to the temperature change is small. To aim.

[0009]

[Means for Solving the Problems]

 In the shock absorber according to the present invention, in order to solve the above-mentioned problems, a piston moves in a pressure tube having a plurality of holes arranged along the axial direction, so that the fluid in the pressure tube has the above-mentioned structure. In a fluid pressure type shock absorber in which a back pressure in the pressure tube based on the resistance to flow out from the hole is exerted to exert a buffering action, a plurality of holes provided in the pressure tube are connected to each other. A cam arranged to face each other from the outer peripheral side of the pressure tube, a cam shaft for rotating the cam, the cam shaft being parallel to the axis of the pressure tube, and a rotation operation section for rotating the cam shaft. And the distance between the hole and the surface of the cam is variable depending on the rotational angular position of the cam.

[0010]

[Action]

 The rotation angle position of the cam is changed by rotating the rotation operation unit. As a result, the distance (jet length) between the hole and the surface of the cam is changed, and the resistance of the fluid is variably adjusted.

[0011]

1 is a sectional front view of a shock absorber 1 according to the present invention, FIG. 2 is an enlarged sectional front view of an adjusting device 20 of the shock absorber 1 of FIG. 1, and FIG. 3 is an enlarged view of the adjusting device 20. FIG.

The shock absorber 1 includes a reservoir tube 11, a pressure tube (inner tube) 12, covers 13 and 14, a piston 15, a piston rod 16, a rod bush 17, a compression coil spring 18, an accumulator 19, and an adjusting device 20. It is being touched.

The reservoir tube 11 and the covers 13 and 14 constitute an entire container that seals and stores the pressure oil HY. The piston 15 slides on the inner peripheral surface of the pressure tube 12 mounted concentrically with the reservoir tube 11. The piston 15 is provided with a check valve that is closed when the piston 15 moves in the left direction (arrow M1 direction) in FIG. 1 and opens when it moves in the opposite direction.

A piston rod 16 is connected to the piston 15, and the piston rod 16 penetrates the cover 14 and the rod bush 17 and projects to the outside. The compression coil spring 18 urges the piston 15 to the left and normally returns the piston 15. The accumulator 19 absorbs the volume change in the chamber 31 due to the position of the piston 15.

Referring to FIGS. 2 and 3, the pressure tube 12 is provided with a plurality of holes 41, 41 ... Arranged along the axial direction. A cam 51 is arranged so as to face the outer peripheral side of the sleeve 12. The cam 51 is provided so as to be parallel to the axis of the pressure tube 12 and is attached so as to rotate integrally with a cam shaft 52 that penetrates through the cover 14 and projects.

An adjustment knob 53 for rotating the cam shaft 52 to adjust its rotational angle position, and a lock nut 54 for locking are attached to the outer end portion of the cam shaft 52. A washer 55 for bearing in the thrust direction is provided on the inner end of the cam shaft 52.

Further, since the pressure oil HY flowing out or jetting from the hole 41 receives a force acting on the cam 51, it is made of synthetic resin or gun metal between the cam shaft 52 and the inner peripheral surface of the reservoir tube 11. Reaction force receivers 56, 56 are attached. The reaction force receiver 56 prevents the cam shaft 52 from vibrating and prevents the performance of the shock absorber 1 from varying. Reference numeral 57 is a retaining ring.

The adjustment device 20 is configured by the cam 51, the cam shaft 52, the adjustment knob 53, the reaction force receiver 56, and the like. Therefore, by operating the adjustment knob 53 to rotate the cam 51, the distance (spout length) e between the hole 41 and the surface of the cam 51 is changed. This increases or decreases the resistance when the pressure tube 12 flows from the inner chamber 31 of the pressure tube 12 through the hole 41 to the outer chamber 32. Therefore, by setting the variable range of the distance e to an appropriate range, The magnitude of the cushioning effect can be adjusted appropriately.

Since this shock absorber 1 varies the ejection length from the hole 41 depending on the rotational angle position of the cam 51, the effect of the fluctuation of the viscosity coefficient of the pressure oil HY is small, and the shock absorbing effect of the temperature change is small. There is little fluctuation.

Further, since the structure of the shock absorber 1 is simple and the conventional metering tube which requires high precision hammering with the pressure tube 12 is unnecessary, the cost can be reduced.

In the above-described embodiment, the cam shaft 52 may be rotated by a motor or the like instead of the adjustment knob 53 or together with the adjustment knob 53. In addition, the structure, shape, size, material, etc. of each part of the shock absorber 1 can be variously changed in accordance with the gist of the present invention.

[0022]

[Effect of device]

 According to the present invention, it is possible to reduce the cost by eliminating the need for a metering tube that requires high precision and accuracy, and to reduce the fluctuation of the cushioning action due to the temperature change.

Therefore, the performance of the shock absorber is not affected by the temperature, and a stable shock absorbing action can be exhibited.

[Brief description of drawings]

FIG. 1 is a sectional front view of a shock absorber according to the present invention.

FIG. 2 is an enlarged sectional front view showing an adjusting device of the shock absorber of FIG.

FIG. 3 is a sectional side view of the adjusting device.

FIG. 4 is a sectional view showing an adjusting mechanism of a conventional hydraulic shock absorber.

[Explanation of symbols]

 1 shock absorber (fluid pressure shock absorber) 12 pressure tube 15 piston 41 hole 51 cam 52 cam shaft 53 adjustment knob (rotation operation part) HY pressure oil (fluid)

Claims (1)

[Scope of utility model registration request] 1. A piston moves in a pressure tube having a plurality of holes arranged in the axial direction, whereby the fluid in the pressure tube flows out from the hole and resistance to flow out from the hole is increased. A fluid pressure type shock absorber configured to exert a cushioning action by back pressure in the pressure tube based on a cam arranged to face a plurality of holes provided in the pressure tube from an outer peripheral side of the pressure tube. A cam shaft for rotating the cam, the cam shaft being parallel to the axis of the pressure tube, and a rotation operating portion for rotating the cam shaft, and the hole depending on the rotation angle position of the cam. A fluid pressure shock absorber, characterized in that the distance from the surface of the cam is variable.