JPS6350510Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a damping force adjusting device for a hydraulic shock absorber used as a suspension system for a vehicle.

As a hydraulic shock absorber used as a hydraulic actuator for the suspension of two-wheeled vehicles, four-wheeled vehicles, etc.
For example, the one shown in Figure 1 has been developed.

A piston rod 3 is slidably inserted into a cylinder 1 via a piston 2, and piston valves 8 and 9 are provided on the piston 2, and two liquid chambers 1 on the left and right are partitioned by the piston 2.
2 and 13 communicate through these piston valves 8 and 9.

An outer tube 4 concentric with the cylinder 1 is provided outside the cylinder 1, and a reservoir consisting of a gas chamber 6 and an oil chamber 5 is defined between the cylinder 1 and the outer tube 4.

A bearing 15 is fixed to the left end of the cylinder 1 and the outer tube 4.
A seal member 16 is provided on the left side, and the piston rod 3 passes through the center of the bearing 15 and the seal member 16 and projects to the outside.

A passage 26 and an oil hole 17 are provided in the piston rod 3, and a rotary valve 27 having one or more ports 18 is rotatably inserted into the passage 26. Rotatably inserted operating rod 2
It is designed to be rotated from the outside via 0.

The operating rod 20 is held by a seal 21 and a backup spring 22.

A valve housing 7 is fixed to the bottom on the right side of the cylinder 1, and a check valve 10 and a base valve 11 are provided within this valve housing 7.

A through hole 24 is bored in the bearing 15, and this through hole 24 allows the gas chamber 6 to communicate with the oil chamber 23, so that oil leaking from the bearing 15 and the seal 19 can be collected into the reservoir side.

When the piston rod is extended, the oil in the liquid chamber 12 is squeezed through the base valve 9 on one side, and the oil in the oil chamber 1 is
Part of it flows out to oil hole 17-port 18-
The oil flows out through the passage 26, exerts a damping force on the rebound side due to the flow resistance of the piston valve 9 and the port 18, and the oil equivalent to the volume of the piston rod 3 that has come out flows into the gap 14.
Oil in the oil chamber 5 is sucked through the check valve 10.

On the other hand, during operation on the pressure side, oil in the liquid chamber 13 flows out from the piston valve 8 into the liquid chamber 12, and at the same time, the oil in the passage 2
6 - port 18 - liquid chamber 1 via oil hole 17
2, pressure side damping force is generated due to the flow resistance of the port 18 and the piston valve 8, and at this time, the amount of oil corresponding to the volume of the intrusion of the piston rod flows into the base valve 11,
When the oil is returned to the oil chamber 5 through the gap 14 and the rotary valve 27 is rotated to allow the port 18 to face and communicate with the oil hole 17 as shown in FIG. 2, a soft damping force is obtained. When the port 18 is in the position where it is blocked from the oil hole 17 as shown in Figure 3, the through hole 1
Hard damping force can be obtained because oil does not flow from 8.

Therefore, when operating on the pressure side, the piston valve 8 is designed to allow oil to flow from the piston valve 8 at a flow rate equal to or greater than the piston speed multiplied by the area obtained by subtracting the piston rod cross-sectional area from the cylinder cross-sectional area, with respect to the throttle at the base valve 11. If the design is not designed to restrict the flow of oil at When submerged in water, the liquid chamber 12 is not filled with oil and no damping force is generated. For this reason, the pressure in the gas chamber 6 is increased to a certain value to prevent the liquid chamber 12 from becoming negative pressure.
Generally, the oil in the oil chamber 5 is forced out by this gas pressure. In particular, when generating a hard damping force as shown in FIG. 3, a considerably high pressure is sealed in the gas chamber 6. Therefore,
When the gas pressure in the gas chamber 6 is low, there is a problem in that the compression side damping force cannot be adjusted over a large range, and when the gas pressure is increased, the seal friction increases and the spring constant also increases. Furthermore, there was a problem in that the durability of the seals 16 and 19 was reduced, resulting in poor damping force if the gas pressure decreased or gas escaped for some reason.

Therefore, the purpose of this invention is to prevent negative pressure in one of the liquid chambers during pressure side operation, to allow a wide adjustment range for the pressure side damping force even when the gas pressure in the gas chamber is low, and to reduce seal friction and spring constant. Moreover, it is an object of the present invention to provide a damping force adjustment device for a hydraulic shock absorber that does not impair the durability of a seal.

To achieve this objective, the present invention is characterized in that oil from the reservoir side oil chamber can be supplied to one of the liquid chambers, which expands during compression, through a check valve.

An embodiment of the present invention will be described below with reference to FIG. 4 and subsequent figures.

FIG. 4 shows a hydraulic shock absorber used as a suspension hydraulic actuator according to a preferred embodiment of the present invention.

That is, the piston rod 3 is slidably inserted into the cylinder 1 via the piston 2, and the piston rod 3 is slidably inserted into the cylinder 1 via the piston 2.
defines two left and right liquid chambers 12 and 13 within the cylinder 1, and the two liquid chambers 12 and 13 communicate with each other via piston valves 8 and 9 provided in the piston 2, respectively.

An outer tube 4 concentric with the cylinder 1 is provided outside the cylinder 1, and both ends of the outer tube 4 are sealed with a bearing 15 and a bottom 25. An annular diaphragm 26 is installed concentrically between the cylinder 1 and the outer tube 4, an oil chamber 5a along the longitudinal direction is defined between the cylinder 1 and the diaphragm 26, and an oil chamber 5a is defined between the outer tube 4 and the diaphragm 26. Similarly, a gas chamber 6a is defined along the longitudinal direction, and an arbitrary amount of gas pressure is filled into the gas chamber 6a from the outside via a gas filling member 28.

A seal member 16 consisting of an oil seal and a dust seal is held at the end of the outer tube 4, and the piston rod 3 slidably passes through the center of the bearing 15 and the seal member 16 and projects to the outside.

A base valve housing 7 is fixed to the right end of the cylinder 1, and the housing 7 is provided with a check valve 10 and a base valve 11.

The housing 7 stands up on the bottom 25, and a gap 14 formed in the leg of the housing 7 allows the oil chamber 5a to communicate with a chamber on the right side of the housing 7.

A through hole 24 is formed in the bearing 15, and this through hole 24 communicates the oil chamber 5a with the oil chamber 23 on the left side of the bearing 15. A vertical passage 26 and a radial oil hole 17 are formed in the piston rod 3, and a rotary valve 27 is rotatably inserted into the passage 26.

Port 18 is bored in rotary valve 27,
This rotary valve 27 is rotationally driven from the outside via an operating rod 20 rotatably inserted into the piston rod 3, and when the port 18 faces the oil hole 17, a soft damping force is obtained.
When it is in a position where it is blocked from the oil hole 17, oil does not flow from here and a hard damping force is generated. However, a plurality of ports having different diameters may be formed, and by selectively opening and closing each port, a damping force may be generated according to the inner diameter of the selected port.

The operating rod 20 is sealed and held by a seal 21 and a back-up spring 22.

The next thing to note is that a passage 29' is formed in the bearing 15, and this passage 29' communicates the oil chamber 23 with the left liquid chamber 12, and a check valve 29 can be opened and closed in the middle of this passage 29'. A check valve 2 is provided to check the oil in the oil chambers 5a and 23 during compression operation.
9 is opened to allow suction into the liquid chamber 12.

Next, we will discuss the operation.

During the extension operation, the piston rod 3 moves to the left in the figure, and at this time, the oil in the liquid chamber 12 flows out into the liquid chamber 13 through the piston valve 9 and port 18, and is softly damped by the piston valve 9 and port 18. You can gain strength. Further, when the rotary valve 27 is rotated via the operating rod 20 to block the port 18, a hard damping force can be obtained since no oil flows therefrom.

Also, the amount of oil corresponding to the volume of the piston rod coming out during the extension operation is oil chamber 5a - gap 4 - check valve 10.
The liquid is sucked into the liquid chamber 13 through the liquid chamber 13.

During compression operation, oil in the liquid chamber 13 flows out into the left liquid chamber 12 via the piston valve 8 and port 18.
A soft damping force is obtained by the flow resistance between the piston valve 8 and the port 18, and a hard damping force is obtained when the port 18 is closed.

What is important here is that if the piston valve 8 is throttled too much, in other words, from the liquid chamber 13 to the liquid chamber 12.
When the piston valve 8 is throttled so that the flow rate flowing into the piston rod is smaller than the flow rate obtained by multiplying the piston speed by subtracting the piston rod cross-sectional area from the cylinder cross-sectional area, the check valve 29 provided on the bearing 15 checks the oil in the oil chamber 5a. Since the oil flows into the liquid chamber 12, the liquid chamber 12 does not become a negative pressure and is filled with oil. Further, since the gas chamber 6a is sealed by the diaphragm 26, no gas can enter, and the desired damping force is generated when the extension operation is started.

The gas chamber 6a can be used by simply filling this extremely low pressure gas by sending the oil from the oil chamber 5a into the liquid chamber 12. This allows the compression side damping force to be increased, and therefore the hard and soft adjustment widths can also be adjusted. It can be taken in large quantities.

The amount of oil corresponding to the volume of the piston rod intrusion during compression is transferred to the oil chamber 5 via the base valve 11 and gap 14.
It is discharged to a.

FIG. 5 shows another embodiment of the present invention, in which the mounting position of the check valve is changed, and the other configurations, functions, and effects are exactly the same as those in FIG. 4.

That is, the valve housing 30 is provided at a position close to the head side of the cylinder 1, and this housing 30
A passage 31 is provided to communicate the oil chamber 5a and the liquid chamber 12, and a check valve 32 for opening and closing the passage 31 is installed in the middle of this passage 31, so that oil is sucked from the oil chamber 5a into the liquid chamber 12 during compression operation, and the oil is removed from the liquid chamber. 12, and the liquid chamber 12 is always filled with oil.
The damping force is generated as desired when shifting to the extension operation.

FIG. 6 shows another embodiment of the present invention, in which the positions of the gas chamber and oil chamber are reversed to those of FIG. 4, and the gas filling passage to the gas chamber is provided in the base valve housing. be.

That is, a gas chamber 6b partitioned by a diaphragm 26 is formed outside the cylinder 1, and the diaphragm 2
An oil chamber 5b is defined between the outer tube 6 and the outer tube 4, and the oil chamber 5b communicates with the oil hole 24 and the gap 4, respectively.

A chamber 33 is located in the center of the base valve housing 7a.
The chamber 33 communicates with the liquid chamber 13 through the through hole 31 and is opened and closed toward the oil chamber 5b through the base valve 11 and the check valve 7a.

The base valve housing 7a has a gas filling hole 3.
2 is formed, and gas is sealed into the gas chamber 6b from the inside of the cylinder through this filling hole 32, and the outer end of the filling hole 32 is sealed via a plug after filling the gas.

An arbitrary gas pressure is sealed in the gas chamber 6b, and even at an extremely low pressure, the oil in the oil chamber 5b passes through the hole 24- during compression operation.
Oil can be supplied to the liquid chamber 12 via the chamber 23, the check valve 29, and the passage 29'.

Furthermore, FIG. 7 shows another embodiment of the present invention, in which a restriction is provided downstream of the check valve. That is, in addition to the configuration shown in FIG.
A check valve 29 is provided in the middle of the passage 29' so that it can be opened and closed freely, and a restriction 34 such as an orifice is installed in the middle of the passage 29' downstream of the check valve 29.
It has been established.

In this case, during compression operation, oil in the oil chamber 5b is sucked into the liquid chamber 12 via the check valve 29 and the throttle 34, but at this time, it is possible to lower the pressure in the liquid chamber 12, and as a result, the pressure in the liquid chamber 12 can be reduced. Liquid chamber 13
This increases the differential pressure between the damping force and the damping force. Similarly, FIG. 8 shows another embodiment of the present invention.

As in FIG. 1, a reservoir consisting of a gas chamber 6 and an oil chamber 5 is divided between the cylinder 1 and the outer tube 4, and a reservoir can be placed at any position in the oil chamber 5.
For example, a pipe 35 extending downward is provided along the axial direction, and the head portion of this pipe 35 is connected to the through hole 24, so that the oil in the oil chamber 5 is not connected to the gas chamber 6 during compression operation. The liquid is supplied to the liquid chamber 12 via the chamber 23, the check valve 29, and the throttle 34. However, it can be used without the diaphragm 34.

In this case as well, only the oil in the oil chamber 5 is sucked into the liquid chamber 12 during the compression operation, so the liquid chamber 12 does not become a negative pressure and is filled with oil.

Similarly, FIG. 9 is substantially the same as that in FIG. 8, in this case chamber 3 corresponding to chamber 23 in FIG.
It is a larger version of 6. In this case, since the chamber 36 is large, a sufficient amount of oil is always stored in the chamber 36, and a sufficient amount of oil can be supplied to the liquid chamber 12 during compression operation.

As described above, the present invention allows oil in the reservoir side oil chamber to be supplied to one of the expanding liquid chambers during compression operation, so this expanding liquid chamber is always filled with oil and does not generate negative pressure. Similarly, because the liquid chamber is filled with oil, the desired extension-side damping force is generated even when the extension operation shifts.
The compression side damping force can be increased even when the gas chamber is at extremely low pressure, which allows for a wide range of hard and soft adjustment, and even if the gas pressure in the gas chamber is low or the gas escapes, the damping force will not fail. The fact that this gas pressure does not occur and that the gas pressure can be kept low means that this gas pressure does not adversely affect the durability of the seals it acts on, prevents the seal friction from increasing, and allows the piston rod to slide smoothly. It has excellent effects such as the ability to

[Brief explanation of the drawing]

Figure 1 is a longitudinal sectional front view of a conventional hydraulic shock absorber, Figure 2
Figure 3 is an enlarged cross-sectional side view of the rotary valve section, Figure 4, Figure 5, Figure 6, Figure 7, Figure 8,
FIG. 9 is a whole or partial longitudinal sectional front view of a hydraulic shock absorber according to another embodiment of the present invention. 1... Cylinder, 2... Piston, 3... Piston rod, 5, 5a, 5b... Oil chamber on the reservoir side, 6, 6a, 6b... Gas chamber, 7... Bearing, 8, 9... Piston valve , 10... Check valve, 11... Base valve, 12, 13...
...Liquid chamber, 15...Head, 26...Diaphragm, 34...Aperture.

Claims (1)

[Claims for Utility Model Registration] (1) A piston rod is movably inserted into the cylinder via a piston, and two liquid chambers are defined within the cylinder via the piston. In a hydraulic shock absorber, two liquid chambers communicate with each other through a base valve and a check valve, and one liquid chamber communicates with a reservoir side consisting of a gas chamber and an oil chamber through a base valve and a check valve. A damping force adjustment device for a hydraulic shock absorber in which an oil chamber is communicated with an upper liquid chamber defined by the piston via a check valve. (2) The damping force adjusting device for a hydraulic shock absorber according to claim 1, wherein the check valve is provided on the bearing. (3) The damping force adjusting device for a hydraulic shock absorber according to claim 1, wherein the check valve is provided near the cylinder head side. (4) A damping force adjusting device for a hydraulic shock absorber according to claim 2 or 3 of the utility model registration claim, which is provided with a throttle in series with a check valve. (5) The damping force adjusting device for a hydraulic shock absorber according to claim 1, wherein the reservoir is composed of a gas chamber and an oil chamber, and the gas chamber and the oil chamber are separated by a diaphragm.