JPS5922357Y2 - Hydraulic shock absorber damping force generator - Google Patents

Description

[Detailed description of the invention] In a hydraulic shock absorber in which a cylinder is filled with oil and a piston is slidably fitted, an elastic valve is installed at the opening of the oil flow hole in order to obtain the desired damping force characteristics. A preset load may be applied to this valve.

Fig. 1 shows the structure of such a conventional damping force generator, in which an oil hole 3 is provided in a piston 2 that is slidably fitted into a cylinder 1 filled with oil. An annular valve 4 made of a flat plate of elastic material is disposed in the inner circumferential portion of the piston 3, and the inner peripheral portion of the valve is fixed to the piston 3.

In addition, a step δ is provided between the piston surface in contact with the inner circumference of the valve 4 and the piston surface in contact with the outer circumference, and a preset load is applied to the valve, in order to obtain the desired damping force characteristics. The dimensional accuracy of this step must be 0.01 mm or more.

However, in the above-mentioned apparatus, it is difficult to obtain a predetermined level difference due to wear of the mold for molding the piston from the sintered alloy, deformation during sintering, etc., and the level difference gradually becomes smaller due to wear of the piston due to use. there were.

The present invention provides a device that can eliminate such drawbacks and easily obtain predetermined damping force characteristics.

Fig. 2 is a side view of a part of the embodiment of the present invention, and Fig. 3 is an enlarged and further longitudinal sectional view of a part of Fig. 2.
A piston 2 is slidably fitted into a cylinder 1 filled with .

This piston is provided with a plurality of oil holes 3 and 6, respectively, and a check valve 8 pressed by a spring 7 is disposed on the upper surface of the piston, and an oil hole 9 is provided in the valve 8.

Further, an annular valve 4 made of an elastic flat metal plate is disposed on the lower surface of the piston 2 so as to face the opening of the oil hole 3, and its inner circumference is fixed to the piston 2 with a nut 10. be.

In addition, an annular flat plate 12 having a predetermined thickness is inserted between the outer periphery of the valve 4 and the opening surface 11 of the oil hole 3, and the opening surface 11 is the same on the inside and outside of the oil hole 3. It forms a plane.

Therefore, the outer circumference of the valve 4 is bent into a conical shape, and the plate 12
A preset load corresponding to the thickness of the valve 4 is generated on the valve 4.

Further, the diameter of the annular flat plate 12 is formed to be larger than that of the valve 4, and an annular stepped portion 13 facing the outer peripheral edge thereof is provided on the opening surface 11 of the oil hole 3.

That is, the stepped portion 13 prevents the annular flat plate 12 from moving, so that when the piston 2 descends, the valve 8 opens and the oil passing through the oil hole 6 generates a relatively small damping force, and when the piston 2 descends, a relatively small damping force is generated. In this case, when the oil pressure in the oil hole 3 becomes higher than the above-mentioned preset load, the valve 4 is further bent to open the oil hole.

Therefore, desired damping force characteristics determined by the preset load and the elasticity of the valve 4 can be obtained.

In this way, the present invention forms the opening surface 11 of the oil hole in a planar shape, and inserts an annular flat plate between the outer peripheral part of the valve 4 and the opening surface, and faces the outer peripheral edge of the flat plate. By providing a stepped portion, a preset load is applied to the valve, and the thickness of the metal plate can easily be about 0.001 mm, so a device having exactly desired damping force characteristics can be obtained.

In addition, since the opening surface 11 of the oil hole 3 is planar, there is no fear that the characteristics will change due to wear of the mold for molding the piston, so the life of the mold is extended and the shock absorber can be manufactured at low cost.

Further, by forming the annular flat plate from a hard metal plate, wear due to use is prevented, so that constant characteristics are maintained over a long period of time.

Moreover, it is extremely easy to manufacture since there is no need for difficult machining to provide a step having an accurate predetermined dimension on the opening surface of the oil hole.

[Brief explanation of drawings]

FIG. 1 is a vertical sectional view of a conventional device, FIG. 2 is a side view of an embodiment of the present invention, with a part thereof cut away vertically, and FIG. 3 is an enlarged view of a part of FIG. 2, taken further in longitudinal section. In the figure, 1 is a cylinder, 2 is a piston, 3 is an oil hole, 4 is a valve, 5 is oil, 6 is an oil hole, 7 is a spring, 8 is a check valve, 9 is an oil hole, 10 is a nut, 11 is the opening surface of the oil hole,
12 is an annular flat plate, and 13 is an annular stepped portion.

Claims (1)

[Scope of utility model registration request] A piston is slidably fitted into a cylinder filled with oil, and an annular valve made of a flat plate of an elastic body is arranged at the opening of an oil hole through which oil flows by movement of the piston. In a hydraulic shock absorber having a fixed inner circumferential portion, a circular flat plate having a predetermined thickness for applying a preset load to the annular valve is flush with the outer circumferential portion of the valve and the inside and outside of the oil hole. An annular step is formed on the opening surface of the oil hole to be inserted between the oil hole and the annular flat plate and to prevent the annular flat plate from moving. Damping force generator for hydraulic shock absorbers.