JPS6114673Y2 - - 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. When the oil chamber is in its neutral position, the oil in the oil chamber in the cylinder flows out into the oil chamber in the reservoir through this stamping 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. −31111).

However, such a valve device requires the closure valve to be attached to a small disk, which is difficult to process and manufacture.Furthermore, even though the movable mass is large, the weight increases due to the addition of the closure valve, and the operability is poor. In many cases, it lacks practicality due to poor response and poor response.

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 serving as a valve case in the base valve device 9 is fixed to the lower end of the cylinder 2. Legs 35 provided at the lower end of the disk 10 stand up on the lower cap 4, and the disk 10 has a liquid chamber in the lower cap 4. It is divided into 11 areas.

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 so as to be openable and closable. A spring or other similar spring member 23 is interposed,
In the stationary state, the check valve 22 is pressed against the valve seats 20 and 21 by the spring member 23 to close the port 19, and in the extended state, the port 19 is closed.
The hydraulic oil from the check valve 22 pushes open the check valve 22 against the spring member 23.

The check valve 22 and the spring member 23 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 lower end of the disk 10, a valve seat 26 is provided to protrude downward from the mouth end of the opening 18a communicating with the pressure side port 18, and a pressure side damping valve 27 consisting of a plate valve is disposed on this valve seat 26 so as to be openable and closable. The port 18 and the opening 18a are opened and closed.

A stamped orifice 28 is formed in the valve seat 26 to allow the opening 18a to communicate with the liquid chamber 11 at all times.

On the flange 17 of the support rod 15, a support plate 30, a spacer 36, and a blocking valve 29 are held in an overlapping manner, and the base end of the damping valve 27 is supported on the spacer 36.

The blocking valve 29 is a cup-shaped elastic leaf valve that is initially loaded. The blocking valve 29 is disposed at the outlet end of the pressure side port 18, that is, upstream of the pressure side damping valve 27, so as to be openable and closable. At times, the pressure side port 18 is closed by its own elasticity, and hydraulic oil is prevented from flowing out from the pressure side port 18 to the opening 18a and the liquid chamber 11 side.
In this case, the spring force of the closing valve 29 itself is equal to the oil level in the upper liquid chamber 7 of the cylinder 2, that is, the bearing 3.
A load equal to the weight of oil inside the cylinder ₂ equal to the difference H (= H ₁ − H ₂ ) between the lower surface height H ₁ of the tank A and the oil level height H 2 of the liquid chamber 12 in the reservoir A It is preset to take charge of

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 outlet of the pressure side port 18 is closed by the closing valve 29, 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 22 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 blocking valve 29 is closed and does not participate in the extension process. Furthermore, during compression, piston 5
is lowered and the liquid chamber 8 is reduced in size, but at this time, the internal pressure of the liquid chamber 8 increases at the time of starting compression, and the hydraulic oil flows into the pressure side port 1.
8, and this pressure pushes the closing valve 29 open against its spring force. (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 force of the closing valve 29 on the compression side damping force is 1 because its load is usually around 200 to 300 g.
Differences in damping force characteristics of about 2 Kgf are 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.

Next, FIG. 4 shows another embodiment of the present invention, in which a blockage valve 31 made of an annular disk valve body is disposed at the outlet end of the pressure side port 18 so as to be openable and closable.
This closing valve 31 is biased in the closing direction by a cup-shaped spring 32 having the same spring force as described above, and the base end of the spring 32 is supported between the disk 10 and the damping valve 27 via a spacer 33. It is. In this case, in the stationary state, the pressure side port 18 is closed by the blockage valve 31, so that no oil falls, and during compression, the pressure of the pressure side port 18 pushes open the blockage valve 31, and the damping valve 27 and orifice 26
It is designed to obtain a compression damping force of .

As described above, the present invention provides a closing valve 2 having a set load equal to supporting the weight of oil inside the cylinder commensurate with the oil level height inside and outside the cylinder in at least the neutral state of the shock absorber.
9 and 31 are attached to the mouth end of the compression side port 18 so as to be openable and closable, 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 opening ports can be provided independently, the opening 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
The figure is a partially cutaway longitudinal side view of the shock absorber, Figure 2 is an enlarged sectional view of the valve part in Figure 1, and Figure 3 is an enlarged sectional view of the valve part at the time of compression start.
FIG. 4 is an enlarged sectional view of a valve portion according to another embodiment. 2...Cylinder, 7...Upper liquid chamber, 10...Disk, 12...Liquid chamber, 18...Pressure side port, 1
8a...opening, 22...check valve, 23...
Growth side suction port, 26... Orifice, 27...
...Compression side damping valve, 29, 31...Opening valve, 32
……spring.

Claims (1)

[Scope of Claim for Utility Model Registration] (1) A compression side port and a rebound side suction port are bored in the disk, a compression side damping valve and an orifice are provided at the mouth end of the opening communicating with the compression side port, and a rebound side suction port is provided. A check valve is provided at the upper port end, and a blockage valve is provided at the outlet end of the pressure side port on the upstream side of the pressure side damping valve so that it can be opened and closed. A shock absorber valve device biased in the closing direction under a spring force equal to the weight of oil inside the cylinder commensurate with the difference in oil level between the inside and outside. (2) The valve device for a shock absorber according to claim 1, wherein the closing valve is a cap-shaped leaf valve subjected to an initial load. (3) A valve device for a shock absorber according to claim 1, which is comprised of a disk valve body that closes only the pressure side port of a blocking valve, and a spring. (4) Utility model registration request where the spring force of the 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 and the oil level height in the liquid chamber in the reservoir when the shock absorber is in its neutral state. A valve device for a shock absorber according to item 3.