JPS6335037Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a pressure-sensing type tank-separate hydraulic shock absorber mainly used in vehicles such as two-wheeled vehicles.

Conventionally, the damping force was made variable by sensing the internal pressure generated in accordance with the stroke of a hydraulic shock absorber, but the present applicant proposed Japanese Patent Application No. 55-151029 (Japanese Unexamined Patent Publication No. 57-76338) and others. This has been proposed in Japanese Patent Application No. 1983-120406 (Japanese Unexamined Patent Publication No. 58-210383).

As shown in Figs. 1 and 2, a piston 2 is housed in a cylinder 1, and as a piston rod 3 connected to the piston 2 expands and contracts, part of the hydraulic oil is transferred to a tank 4 with gas sealed inside. In this hydraulic shock absorber, a relief valve 6 is provided at the inlet of the tank 4 to provide resistance to the hydraulic oil flowing in during pressure side operation, and a relief spring 7 of the relief valve 6 is supported. One end of the spool 8 is connected to the atmosphere chamber 9, and the other end is connected to the oil reservoir chamber 5.
The valve plate 10 facing the spool 8 and fitted into the spool 8
is locked by the valve case 11 to prevent the spool 8 from moving toward the atmospheric chamber 9, and the relief setting pressure is changed in proportion to the pressure in the oil reservoir chamber 5.

The inside of the tank 4 is defined by a free piston 12 into a gas chamber 13 and an oil reservoir chamber 5,
During compression operation, the hydraulic oil in the lower chamber F of the cylinder 1 enters the oil chamber 15 of the tank 4 through the oil feed pipe 14, and is introduced into the oil reservoir chamber 5 via the relief valve 6.

The pressure in the oil reservoir chamber 5 is the amount of oil, that is,
It changes depending on the stroke position of the piston rod 3. Therefore, the set pressure of the relief valve 6 changes in response to the pressure in the oil reservoir chamber 5, which changes in proportion to the stroke position of the piston rod.

By the way, the outside temperature or the pistons 2, 12
The temperature of the hydraulic oil rises and expands depending on the frequency of operation of the hydraulic oil, which is pressed by the free piston 12 and changes the volume of the gas chamber 13. As a result, the gas chamber 1
There is a problem in that the spring constant of No. 3 changes, and therefore the relief stroke position of the relief valve changes.

This idea was made to solve the above-mentioned problem, and the compression side damping valve is operated according to the displacement of the swing arm or link.
It is an object of the present invention to provide a pressure-sensing type tank-separate hydraulic shock absorber that is not affected by temperature changes.

Embodiments of the present invention will be described below based on the drawings.

First, to explain the configuration, as shown in Figure 3,
The lower end of the cylinder 1 is attached to the lower side 16A of the frame 16, and the upper end is connected to the swing arm 18 via links 17A and 17B. On the other hand, the tank 4 is fixedly installed along the side 16B of the frame 16, and both are connected by an oil pipe 14.
Note that a rear wheel 19 is attached to the end of the swing arm 18.
is pivoted.

The cylinder 1 is in this embodiment similar to that of FIG. 1, and the tank 4 will be described with reference to FIG.

The tank 4 includes a tank body 20 and a valve body 21. The inside of the tank body 20 has a gas chamber E formed by the free piston 12 and the cover 22.
and an oil sump chamber D.

The valve body 21 is connected to the tank body 20 by an end bolt 23.
3, the hollow pipe 24 and cover 2 are caulked together.
5 defines an oil chamber C.

Further, a bolt 26 is screwed into the end bolt 23, and a relief valve 29 is attached to the bolt 26 as a compression side damping valve, which is in sliding contact with the inner surface of the hollow pipe 24 through a set piece 27 that is in sliding contact with the inner surface of the hollow pipe 24, and is equipped with a deflection valve 28. The interior of the hollow pipe 24 is divided into an oil chamber A and an oil chamber B.

The relief valve 29 is biased by a relief spring 30 interposed between the end bolt 23 and is locked to the head of the bolt 26. In this state, the relief valve 29 is provided in the hollow pipe 24 and connects the oil chamber A and the oil chamber C. The communicating orifice 31 is closed. Reference numeral 32 denotes a check valve, which is biased by a spring 33 interposed between it and the end bolt 23, and is in contact with the lower surface of the relief valve 29. Also, a check valve 32 is provided in the hollow pipe 24 opposite to the check valve 32. A suction port 34 is provided.

On the other hand, a valve cavity 35 is formed in the tank body 20 and is perpendicular to the axis, and rotary valves 36 and 37 are provided facing each other in the valve cavity 35.

The oil chamber B includes a passage 38 provided in the end bolt 23, a valve cavity 35, and a rotary valve 36.
and 37, communicating with the oil chamber C via passages 39 and 40 arranged in parallel in the tank body 20, a gap 41, and a passage 42 provided in the valve body 21,
The oil chamber C is a passage 4 provided in the tank body 20.
3 to the oil reservoir chamber D.

The rotary valve 36 is provided with a valve hole 44, as shown in detail in FIG.
It rotates to open and close communication with the passage 39. As shown in FIG. 3, this lever 45 engages with the link 17B and is rotated by the swinging of the swing arm 18.

The rotary valve 37 also has orifices 46 with different opening areas, as shown in detail in FIG.
A to 46B are provided to constitute a variable orifice whose opening degree with respect to the passage 40 is changed by the rotation of the adjuster 47.

Note that 48 is a detent mechanism that biases the ball 49 with a spring 50 and locks the rotary valves 36 and 37.

Next, the effect will be explained.

When the piston rod 3 is compressed, the hydraulic oil introduced by the piston rod 3 flows from the lower chamber F of the cylinder 1 into the oil chamber A of the tank 4 through the oil feed pipe 14. While the piston speed is low, the oil in the oil chamber A opens the flexible valve 28 and enters the oil chamber B, and a damping force is generated by the flexible valve 28. The oil that has entered the oil chamber B passes through the passage 38 and the valve cavity 35, and most of the oil passes through the rotary valve 36, the passage 39, the gap 41,
The oil enters the oil chamber C through the passage 42, and part of the oil also enters the oil chamber C through the rotary valve 37, the passage 40, the gap 41, and the passage 42, and the oil in the oil chamber C passes through the passage 43 and enters the oil sump chamber D. enter.

Then, when the piston speed reaches a high speed, the pressure difference between the oil chamber A and the oil chamber B before and after the relief valve 29 becomes large, so that the relief valve 29 moves against the relief spring 30 and opens the orifice 31. As a result, the oil in the oil chamber A flows directly from the orifice 31 to the oil chamber C, thereby providing damping characteristics for high-speed cutting.

Then, when the piston stroke reaches the second half,
As shown in FIG. 3, the link 17B rotates in the direction of the arrow. Then, the lever 45 engaged with the link 17B also rotates in the direction of the arrow, thereby rotating the rotary valve 36, and the communication state between the valve hole 44 and the passage 39 shown in FIG. 5 is interrupted. As a result, oil chamber B and oil chamber C are communicated only by the rotary valve 37, and the pressure in oil chamber B is
It becomes high due to the drawing resistance of the orifices 46A to 46D. Therefore, the differential pressure between oil chamber A and oil chamber B becomes smaller, and as a result, the relief pressure that moves the relief valve 29 against the relief spring 30 is lowered, and a large damping force is obtained, thereby preventing bottoming out. Prevented. This relief pressure is
Turn the adjuster 47 and orifice 46A~4
It can be adjusted by selecting the opening area of 6D.

In this way, the relief of the relief valve is similar to cutting off the communication of the rotary valve 36 with the lever 45.
and mechanically dependent on the piston stroke associated with the displacement of 17A. Therefore, it is not affected by expansion of the hydraulic oil due to temperature changes.
Note that the pressure side damping valve is not limited to the relief valve described above, and it goes without saying that other valves can be used. As explained above, according to the present invention, since the compression side damping valve is operated in accordance with the displacement of the swing arm, the operation of the compression side damping valve is not affected by temperature changes, and good steering stability is always achieved. This has the effect of improving performance and riding comfort.

[Brief explanation of the drawing]

1 and 2 are cross-sectional views showing the main parts of the conventional device, FIG. 3 is an overall view showing the embodiment of the present invention, FIG. 4 is a cross-sectional view showing the tank, and FIG. Fig. 6 is a sectional view taken along the line arrow, and Fig. 6 is a - of Fig. 4.
It is a sectional view taken along the line. 1... Cylinder, 2... Piston, 3... Piston rod, 4... Tank, 12... Free piston, 17A, 17B... Link, 18... Swing arm, 21... Valve body, 23... End bolt, 24...Hollow pipe, 28...Deflection valve, 29...Relief valve, 30...Relief spring, 31...Orifice, 35...
Valve cavity, 36, 37...Rotary valve, 3
8, 39, 40, 42, 43...Aisle, 41...
Gap, 44...Valve hole, 45...Lever, 46
...Orifice, A, B, C...Oil chamber, D...Oil sump chamber.

Claims (1)

[Scope of utility model registration request] In a hydraulic shock absorber, a piston is slidably housed in a cylinder, and as the piston strokes, a portion of the hydraulic oil is guided into the oil reservoir chamber of the tank, which has gas sealed inside. A pressure side damping valve is provided, flow paths are arranged in parallel so as to communicate the pressure side damping valve and the oil reservoir chamber, a rotary valve is interposed in one of these flow paths, and the rotary valve is connected via a link mechanism. A hydraulic shock absorber is connected to a swing arm, and the movement of the swing arm is converted into rotational motion by a link mechanism to open and close a rotary valve to change damping force.