JP2518483Y2 - Hydraulic shock absorber - Google Patents

Description

[Detailed Description of the Invention] [Industrial field of application] The present invention is for use in a front fork that doubles as a shock absorber and a fork that is interposed between a vehicle body and wheels of a motorcycle or the like and damps vibrations from the road surface. A suitable hydraulic shock absorber.

[Conventional technology]

As this type of conventional front fork, for example, the one disclosed in Japanese Utility Model Laid-Open No. 63-50795 is known.

This front fork slidably inserts the inner tube, which is the wheel side tube, into the outer tube, which is the wheel side tube.The damper cylinder is erected from the lower center of the outer tube, and the piston rod is moved through the piston in the damper cylinder. The piston divides into two upper and lower oil chambers in the damper cylinder.The two oil chambers are opened and closed via the port and leaf valve provided in the piston, and also the lower passage of the piston rod and this passage. It is opened and closed via a needle valve.

The needle valve is driven vertically from the outside to adjust the opening of the passage in the piston rod, and in the low speed range, the oil in the upper oil chamber flows out to the lower oil chamber through the passage narrowed by this needle valve. When the orifice characteristic damping force is generated, the leaf valve of the piston opens in the high speed range and the valve characteristic damping force is also generated.

[Problems to be solved by the device]

In the above-mentioned front fork, only the needle valve is provided in the passage in the piston rod, so that there is a problem that only the damping force in the low speed range can be adjusted by the needle valve.

Therefore, an object of the present invention is to provide a hydraulic shock absorber capable of adjusting the damping force not only in the low speed region but also in the high speed region and improving the riding comfort.

[Means for solving the problem]

In order to achieve the above object, the configuration of the present invention is such that the wheel side tube and the vehicle body side tube are slidably fitted, and the damper cylinder is erected from the lower center of the wheel side tube.
A hollow piston rod is movably inserted into the damper cylinder via a piston, and the piston divides two oil chambers in the damper cylinder.The two oil chambers are provided in a port and a valve provided in the piston and in the piston rod. In a hydraulic shock absorber that communicates with each other through a passage and a valve, when the two oil chambers are connected, a needle valve that is movable in the axial direction and the rotational direction in the middle of the passage in the piston rod and a relief spring close And a relief valve biased in a direction is provided so as to be openable and closable, and one end of the relief spring is supported by a slider that is converted into axial movement by axial and rotational movements of the needle valve. The valve is connected to a control rod that is inserted into the piston rod from the outside so that it can move axially and rotationally. And it is characterized in that is.

[Action]

In the low speed range, the oil flowing through the passage in the piston rod is throttled by the needle valve to generate a damping force, and in the high speed range, the relief valve opens and the damping force is generated. When the control rod is moved in the axial direction or the rotation direction, the needle valve moves in the same direction, and the opening degree of the needle valve and the spring load of the relief spring are adjusted.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings.

1 and 2 show a hydraulic shock absorber as a front fork according to an embodiment of the present invention.

A vehicle body side tube 2 which is an inner tube is slidably inserted into a wheel side tube 1 which is an outer tube,
A damper cylinder 3 stands up from the center of the lower part of the wheel-side tube 1, a hollow piston rod 5 is movably inserted into the damper cylinder 3 via a piston 4, and the piston rod 5 is attached to a vehicle-body-side tube via a cap body 6a. Two
It is connected to.

A spacer 7 and a seat 8 are provided below the cap body 6a, and a suspension spring 9 is interposed between the seat 8 and an upper portion of the damper cylinder 3 to constantly urge the vehicle body side tube 2 and the piston rod 5 in the extending direction.

The piston 4 has two upper and lower oil chambers inside the damper cylinder 3.
The two oil chambers 10 and 11 are divided into 10 and 11 and are opened and closed via a port 12 provided in the piston 4, an extension leaf valve 12a and a check valve 12b.

The first hollow valve body at the bottom of the piston rod 5.
5a and the second hollow valve body 13a are connected. A passage 14 communicating with the lower oil chamber 11 is provided in the second valve body 13a.
And a port 28 communicating with the upper oil chamber 10 are formed, and the passage 14
The port a communicates with the port 28 via the chamber of the first valve body 5a. Further, the passage 14 communicates with the upper oil chamber 10 via a passage shown by a dotted line formed in the second valve body 13a in the radial direction.

The needle valve 18a is inserted into the first and second valve bodies 5a and 13a so as to be movable in the rotational direction and the vertical axis direction.
A leaf valve 16a, which is a plate-shaped relief valve, is openably and closably provided at the upper opening end of the port 28 provided in the valve body 13a of the valve body 13a, and the needle valve 18a has a passage 2 communicating with the passage 14.
9 is formed.

The clearance passage on the outer circumference of the needle head of the needle valve 18a moves along the second valve body 1 as the needle valve 18a moves up and down.
The opening is adjusted in cooperation with the inner circumference of 3a.

A relief spring 31 for urging the relief valve 16a in the closing direction is interposed between the upper side of the relief valve 16a and the slider 30, and the slider 30 is provided with a needle valve 18a.
When the needle valve 18a rotates, the slider 30 moves up and down via the screw, and the spring load of the relief spring 31 is adjusted.

The needle valve 18a is connected to the control rod 25 via the pin 33, and the control rod 25 is connected to the second adjuster 34 inserted into the cap body 6a,
The adjuster 34 is connected to the first adjuster 35 via the detent 37 and the screw 36, and the first adjuster 35 is screwed to the cap body 6a. Detent 37 has a long hole 38
It is fitted to and guides the vertical movement.

When the second adjuster 34 is rotated, the second adjuster 34
The adjuster 34 moves up and down, and the needle valve 18a moves up and down via the control rod 25 to adjust the opening area of the passage on the outer circumference of the valve head.At this time, the slider 30 also interlocks with the spring load of the relief spring 31. Also adjust.

When the first adjuster 35 is rotated, the second adjuster 34 is rotated integrally with the rotation of the first adjuster 35, and the needle valve 18a is also rotated.

At this time, the slider 30 is converted into axial movement via a screw and moves up and down, and only the spring load of the relief spring 31 is adjusted.

At the time of extension, in the low speed range, the oil in the upper oil chamber 10 passes through the gap in the outer circumference of the needle head of the needle valve 18a and the passage 14 to the lower oil chamber 1
Flows to 1 and generates damping force in the low speed range.

In the medium speed range, the port 12 opens the leaf valve 12a, and in the high speed range, the relief valve 16a opens to generate damping force in the middle and high speed ranges depending on the valve characteristics.

When compressed, the oil in the lower oil chamber 11 will pass through the passage 14 and the needle valve.
It flows into the upper oil chamber 10 through the outer peripheral gap of 18a, and part of it flows into the upper oil chamber 10 by opening the check valve 12b from the port of the piston 4.

The magnitude of the damping force is set by adjusting the spring load of the relief spring 31 in the relief valve 16a, adjusting the opening area of the clearance on the outer circumference of the needle head of the needle valve 18a, or simultaneously adjusting it.

[Effect of device]

 The present invention has the following effects.

(1) Since the passage connecting the two oil chambers partitioned by the piston is provided in the piston rod, and the needle valve and the relief valve are provided in the middle of this passage so as to be openable and closable,
The damping force is generated by the needle valve in the low speed range, and the damping force is generated by the relief valve in the high speed range.

(2) A control rod that can be operated from the outside is connected to the needle valve, and the slider that supports the relief spring is converted into axial movement by the movement of the needle valve. Therefore, the needle valve can be operated by operating one control rod. The structure is simple because the opening degree of the passage and the spring load of the relief spring can be adjusted simultaneously or separately by using, and no separate operating mechanism is required.

(3) Since only one control rod is inserted into the hollow piston rod, the structure is simple and it is not necessary to increase the inner diameter of the hollow portion of the piston rod, so that the strength of the piston rod can be maintained.

[Brief description of drawings]

FIG. 1 is a partially longitudinal front view of a hydraulic shock absorber according to an embodiment of the present invention, and FIG. 2 is a partially enlarged sectional view of FIG. 1 …… Wheel side tube, 2 …… Vehicle body side tube, 3 ……
Damper cylinder, 4 ... Piston, 5 ... Piston rod, 10,11 ... Oil chamber, 12 ... Port, 12a ... Valve,
14,29 ... passage, 16a ... relief valve, 18a ... needle valve, 25 ... control rod, 30 ... slider, 31 ... relief spring.

Claims (1)

(57) [Scope of utility model registration request] 1. A wheel side tube and a vehicle body side tube are slidably fitted together, a damper cylinder is erected from the lower center of the wheel side tube, and a hollow piston rod is movable in the damper cylinder via a piston. Is inserted into the damper cylinder, the two oil chambers are defined in the damper cylinder, and the two oil chambers are connected to each other through a port and a valve provided in the piston and a passage and a valve in the piston rod. And a needle valve that is movable in the axial direction and the rotation direction and a relief valve that is urged in the closing direction by a relief spring are openably and closably provided in the passage in the piston rod that connects the two oil chambers. , One end of the relief spring is supported by a slider that is converted into axial movement by axial and rotational movements of the needle valve. Further wherein the hydraulic shock absorber needle valve characterized in that attached to the control rod inserted freely axially and rotationally moved from the outside into the piston rod.