JPH0137350Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION This invention relates to a damping force adjusting device for a hydraulic shock absorber used, for example, as a front cushion of a motorcycle.

Conventionally, as shown in FIG. 1, a damping force adjustment device during the extension process has a seat pipe 2 installed inside a bottom case 1 with an oil hole 3 for generating a damping force that communicates with the inner and outer oil chambers. An adjustment rod 5 having oil holes 4 of different sizes in the circumferential direction corresponding to the oil holes 3 is fitted into the sheet pipe 2, and the rod 5 is rotated to obtain the desired adjustment. A desired damping force adjustment value is set by associating the oil hole 3 with the different diameter oil hole 4 of a size required to obtain a damping force.

However, this type of adjustment means can only provide intermittent damping values in fixed stages based on the size of the oil holes of different diameters, so it is difficult to handle all kinds of damping applications.
It was not possible to adjust the attenuation value steplessly over a wide range.

Therefore, the object of this invention is to provide a damping force adjustment device for a hydraulic shock absorber that can perform accurate adjustment according to the application without causing any trouble in adjusting the damping force.

An embodiment of this invention will be described below based on the drawings.

Figure 2 shows hydraulic shock absorber 1 used in motorcycles.
1, 12 is a bottom case, and a fork pipe 1 is inserted into the bottom case 12 from above.
3 is slidably inserted, and this fork pipe 1
3 and the outer circumferential surface of a sheet pipe 14 installed concentrically on the inner bottom surface of the bottom case 12 are provided so as to come into sliding contact, and as the fork pipe 13 expands and contracts, the sealed oil 15 is applied to the sheet. Damping force is obtained by flowing through each oil hole of the pipe 14.

A damping force generating mechanism 16 during the extension process is provided at the upper end of the sheet pipe 14 described above.

As shown in FIG. 3, this damping force generation mechanism 16 includes an oil hole 19 that is bored in the upper part of the seat pipe 14 and communicates between the inner and outer oil chambers 17 and 18 that are partitioned by the seat pipe, and the oil hole 19. 19, a cylindrical valve 20 that is fitted into the seat pipe 14 so as to be openable and closable, and a coil spring 2 that biases the valve downward.
1 and an adjustment rod 22 for adjusting the spring pressure.

As shown in FIG. 4, the above-mentioned cylindrical valve 20 is formed into a stepped cylindrical body with a large diameter at the upper outer periphery and a small diameter at the lower outer periphery. The small diameter portion 24 of the outer circumference corresponds to the oil hole 19 of the seat pipe 14, and the small diameter portion 24 of the outer circumference corresponds to the oil hole 19 of the seat pipe 14. Oil chamber 1
A cavity 25 is formed for guiding the oil 15 from 8. The lower end surface of the valve is brought into contact with the inner peripheral stepped surface 26 of the seat pipe 14, and this contact surface is provided as the valve surface 27 for generating damping force, and the upper end surface is provided as the upper spring seat surface of the coil spring 21. The cylindrical valve 20 is always urged downward.

The above-mentioned adjustment rod 22 is screwed into a rod support ring 28 attached to the upper end of the seat pipe 14 so that it can move forward and backward. Its lower end presses the coil spring 21 downward,
The spring pressure is adjusted based on the forward and backward movement of the adjustment rod 22, and the opening degree of the valve surface 27 is adjusted.

If the damping force adjustment device configured in this way is used, the oil 15 will be transferred to the outer oil chamber 1 during the extension process.
8, the oil is led to the inner oil chamber 17 through the oil hole 19 of the seat pipe, the cavity 25, and the valve surface 27. At this time, a damping force is obtained when the valve surface 27 flows, and a desired damping value can be set steplessly by adjusting the pressure of the valve surface 27 based on the rotation of the adjustment rod 22 as appropriate. .

As mentioned above, this idea has a cylindrical valve that can be opened and closed freely corresponding to the oil hole in the seat pipe, and the degree of opening of the valve surface is adjusted based on the biasing pressure of this valve. can be easily set up.

[Brief explanation of the drawing]

Figure 1 is a vertical cross-sectional view of main parts showing a damping force adjustment device for a hydraulic shock absorber used in a conventional motorcycle;
The figure is a vertical sectional view showing a hydraulic shock absorber equipped with the damping force adjusting device of this invention, Figure 3 is a longitudinal sectional view of the main part showing the damping force adjusting device, and Figure 4 shows the operating state of the cylindrical valve. FIG. 11...Hydraulic shock absorber, 14...Sheet pipe,
16... Damping force generation mechanism, 19... Oil hole, 20...
... Cylindrical valve, 21 ... Coil spring, 22 ... Adjustment rod, 26 ... Inner peripheral stepped surface, 27 ... Valve surface.

Claims (1)

[Scope of utility model registration request] A hydraulic shock absorber in which oil sealed inside the bottom case flows through the oil hole of the seat pipe and the flow path of the damping force adjustment rod to generate damping force based on the extension stroke of the fork pipe inserted into the bottom case. In the damping force adjusting device, a damping force adjusting rod is screwed into the upper end of the seat pipe so that it can move forward and backward, and a cylindrical valve corresponding to the oil hole of the seat pipe is slid in the axial direction of the pipe. The cylindrical valve has a small diameter portion on the lower outer periphery, and has a lower end surface in contact with the inner stepped surface of the seat pipe, and is between the upper end surface and the lower end surface of the damping force adjustment rod. A coil spring is interposed between the cylindrical valve and the cylindrical valve to urge the cylindrical valve downward, and a gap between the lower end surface of the cylindrical valve and the inner peripheral stepped surface of the seat pipe is formed as a valve surface for adjusting the damping force. A damping force adjustment device for a hydraulic shock absorber, characterized in that a hollow portion is formed between the small diameter portion of the pipe and the inner peripheral surface of the seat pipe.