JPS6114672Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a valve device for a shock absorber, and more particularly to a valve device for a shock absorber that is suitable for use with a base valve that prevents oil from falling when it is stationary.

In a conventional shock absorber, the cylinder is divided into upper and lower oil chambers via a piston, a reservoir consisting of an upper gas chamber and an oil chamber is defined on the outer periphery of the cylinder, and a lower oil chamber in the cylinder is separated via a base valve. It is designed to open and close the oil chamber in the reservoir. However, with this base valve,
A leaf valve as a compression side damping valve is arranged on the valve seat of the valve case so that it can be opened and closed freely.
A stamped orifice is formed between this leaf valve and the valve seat, and this orifice communicates the lower oil chamber in the cylinder with the oil chamber in the reservoir. In the neutral position, which is the stationary state, the oil in the oil chamber in the cylinder flows out into the oil chamber in the reservoir through this stamped orifice. On the other hand, gas in the reservoir leaks and enters the oil chamber above the cylinder, causing an oil level drop phenomenon in which the oil level in the oil chamber in the reservoir becomes equal to the oil level in the upper oil chamber of the cylinder.

This phenomenon gives the occupant a stiff feeling at the beginning of the shock absorber's operation, and causes aeration as the shock absorber progresses.
For this reason, a base valve device has been developed in which an orifice with a relatively large diameter is bored in the disk of the base valve, and a plate-shaped valve installed at the end of the orifice mouth prevents the hydraulic oil from falling.
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However, such a valve device requires the closure valve to be attached to a small disk, which is difficult to process and manufacture.Furthermore, since the movable mass is large even as it is, the weight increases with the addition of the closure valve, resulting in poor operability. Responsiveness deteriorates and there are many aspects that lack practicality.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a valve device for a shock absorber that prevents hydraulic pressure from dropping when left unused, has good operability and responsiveness, and is easy to process.

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

A cylinder 2 is inserted concentrically into the outer shell 1, a bearing 3 is fixed to the head portions of the outer shell 1 and the cylinder 2, and the lower end of the outer shell 1 is connected to a lower cap 4.

A piston rod 6 is slidably inserted into the cylinder 2 via a piston 5. The piston 5 defines two upper and lower liquid chambers 7 and 8 within the cylinder 2, and the piston rod 6 passes through the bearing 3.

A disk 10 in the base valve device 9 is fixed to the lower end of the cylinder 2.
Legs 35 provided at the lower end stand up on the lower cap 4, and the disk 10 defines a liquid chamber 11 within the lower cap 4.

A reservoir A is formed between the outer shell 1 and the cylinder 2, and this reservoir A consists of a lower liquid chamber 12 and an upper gas chamber 13.

Inside the piston 5 are provided valve members and passages that open and close the two upper and lower liquid chambers 7 and 8 to generate a damping force during expansion, and within the bearing 3 there are also upper liquid chambers 7 and gas passages. A valve member and passageway are provided for opening and closing the chamber 13.

Liquid chamber 11 at the bottom of the disk and liquid chamber 1 in reservoir A
2 communicate with each other via passages 14 provided in leg portions 35.

A support rod 15 is inserted and fixed in the center of the disk 10, and upper and lower flanges 16,
17 are provided. One or more pressure side ports 18 and expansion side suction ports 19 are bored in the disk 10 to communicate the upper and lower liquid chambers 8 and 11.

Valve seats 20 and 21 are protruded from the disk 10, and a check valve 22 made of a plate valve is placed on the valve seats 20 and 21, and a plate spring or other material is installed between the check valve 22 and the flange 16. A similar spring member 23 is interposed, and in a stationary state, this spring member 28 presses the check valve 22 against the valve seats 20, 21 to
When the check valve 22 is extended, hydraulic oil from the port 19 pushes the check valve 22 open against the spring member 23.

The check valve 22 and the spring member 28 have a through hole 24,
25 are formed, and the pressure side port 18 is always opened to the liquid chamber 8 at the lower part of the piston through the through holes 24 and 25.

At the bottom of the disk 10, a valve seat 26 is provided to protrude downward from the mouth end of the pressure side port 18, and a pressure side damping valve 27 consisting of a plate valve is disposed on this valve seat 26 to open and close the port 18. It's getting old.

A stamped orifice 28 is formed in the valve seat 26 to allow the port 18 to communicate with the liquid chamber 11 at all times. A guide 2 is placed on the flange 17 of the support rod 15.
9, a support plate 30, and a spacer 31 are held one on top of the other, and the base end of the damping valve 37 is supported on the spacer 31.

A cap-shaped closure valve 32 is inserted into the outer periphery of the guide 29 so as to be movable up and down.
A spring 34 is interposed between the flange-shaped spring seat 33 provided on the guide 29 and the spring 34, and this spring 34 pushes up the normally closed valve 32 and presses it against the lower surface of the disk 10, and prevents the hydraulic oil leaking from the stamping orifice 28 when it is stationary. The liquid chambers 11 and 1
This prevents you from missing out on 2. In this case, the spring force of the spring 34 is determined by the oil level height in the upper liquid chamber 7 of the cylinder 2, that is, the lower surface height _H1 of the bearing 3 and the oil level in the liquid chamber 12 in the reservoir A, at least when the shock absorber is in the neutral state. Difference H (= _{H 1
-H2} ) is preset to carry a load equal to supporting the weight of oil inside the cylinder 2.

More specifically, a shock absorber is attached to the vehicle body, and in its stationary state, the shock absorber is in a neutral state. on the other hand,
A weight corresponding to the amount of oil in the cylinder 2 acts on the top surface of the blockage valve 32, and a weight corresponding to the oil level in the reservoir A acts on the back surface of the blockage valve 32. In order to prevent cylinder 32 from opening, at least the cylinder 2 in the neutral state must be
The closing valve 32 may be closed with a spring force equal to supporting the weight of the oil inside the cylinder corresponding to the difference between the oil level in the cylinder A and the oil level in the reservoir A.

At this time, the spring force that is equal to the weight of oil inside the cylinder corresponding to the oil level height should be set at least in the neutral state, but the spring force should be set at least in the neutral state, but the spring force should be set at the oil level at any position from the neutral state to the maximum extension. It is also possible to set the spring force to be equal to the weight of the oil inside the cylinder.

Next, we will discuss the operation.

In a stationary state, since the closing valve 32 of the embossing orifice 28 is closed, the hydraulic oil in the liquid chamber 8 at the lower part of the piston does not escape to the liquid chambers 11 and 12, so that the oil level does not drop. (Fig. 2) When the piston 5 is extended, the piston 5 rises, and at this time, the damping force generator inside the piston 5 generates an extension-side damping force, and when the liquid chamber 8 is expanded, the check valve 32 is moved against the spring member 23. is opened, and the hydraulic oil in the liquid chambers 11 and 12 is sucked in through the expansion side suction port 19 to prevent negative pressure. In this case, the occlusion valve 32 is closed and does not participate in the extension process.

Furthermore, during compression, the piston 5 descends and the liquid chamber 8 is reduced, but at this time, when compression starts, the internal pressure of the liquid chamber 8 rises and hydraulic oil flows out from the pressure side port 18 and the stamped orifice 28, and this pressure closes the closing valve. 32 is pushed open against the spring 34. (Fig. 3) When the compression speed increases from the state shown in Fig. 3,
The hydraulic oil from the pressure side port 18 pushes the pressure side damping valve 27 open, and the stamped orifice 28 and the pressure side damping valve 2
7 generates a normal compression damping force.

The influence of the spring 34 on the compression side damping force is 1 to 2 kg since its load is usually around 200 to 300 g.
The difference in damping force characteristics is considered to be within the error range and can be ignored. The present invention also relates to a so-called standard double-tube hydraulic shock absorber in which gas is to be filled in the reservoir A, and when gas is filled, the oil level in the operating cylinder does not drop.

The stamped orifice 28 is stamped into the annular seat 26 of the compression side damping valve 27 for generating compression side damping force, but this orifice 28 can also be used even if a notch or a small hole is formed in the damping valve 27 itself. It is.

The compression side damping force is generated by further deflecting the damping valve 27 from the state shown in FIG.

As described above, the present invention has a coil spring 34 with a set load equal to supporting the weight of oil inside the cylinder corresponding to the oil level height inside and outside the cylinder in at least the neutral state of the shock absorber, and a cap-shaped closing valve 32. By attaching it to the bottom of the disk 10, which is the base valve case, so that it can be opened and closed, it is possible to prevent the oil level in the cylinder from falling when left unused, and the movable mass can also be reduced, improving operability and responsiveness, and improving the expansion pressure. Since the open ports can be provided independently, the open ports can be designed freely and the suction performance is good.

[Brief explanation of the drawing]

The attached drawings relate to one embodiment of the present invention and are
2 is an enlarged sectional view of the valve portion of FIG. 1, and FIG. 3 is an enlarged sectional view of the valve portion at the time of compression start. 2...Cylinder, 7...Upper liquid chamber, 10...Disk, 12...Liquid chamber, 18...Pressure side port, 2
2... Check valve, 23... Extension side suction port,
27... Compression side damping valve, 28... Orifice, 32
...Closing valve, 34...Coil spring.

Claims (1)

[Scope of Claim for Utility Model Registration] (1) A compression side port and a rebound suction port are provided in the disk, a compression damping valve and an orifice are provided at the lower mouth end of the compression side port, and a compression side damping valve and an orifice are provided at the lower mouth end of the compression side port. A check valve is provided at the end, and the pressure side damping valve and the orifice are covered by a blockage valve that can be opened and closed freely. The shock absorber valve device is energized in a closing manner under a spring force equal to supporting the weight of oil in the valve. (2) The valve device for a shock absorber according to claim 1, wherein the blocking valve is cap-shaped. (3) A valve device for a shock absorber according to claim 1, in which the closing valve is pushed up from the rear side by a coil spring. (4) Request for utility model registration in which the spring force of the coil spring is equal to supporting the weight of the oil amount in the upper liquid chamber in the cylinder, which is the difference between the lower surface of the bearing in the neutral state of the shock absorber and the oil level height in the liquid chamber in the reservoir. A valve device for a shock absorber according to item 3.