JPH0235064Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a hydraulic shock absorber used in a hydroneumatic suspension system.

[Conventional technology]

Various proposals have been made for hydraulic shock absorbers used in hydropneumatic suspension systems. To show an example of a conventional hydraulic shock absorber, as shown in Fig. 4, a piston d is installed in a cylinder b located inside a mount a and a sliding tube c installed on the axle side (wheel side). In a configuration in which cylinder b expands and contracts when the axle moves up and down relative to cylinder b, which is stored and connected to the vehicle body side (body side), a spherical accumulator e is attached to cylinder b at a position above mount a. It is set up. Inside this accumulator e,
It is separated into a gas chamber g and an oil chamber h by a diaphragm f, and an oil chamber i above the piston d is communicated with the oil chamber h via a damping valve j. Oil is configured to flow back and forth between the oil chamber h and the oil chamber h via a damping valve j, and therefore, the volume change of the oil chamber h is caused by the accumulator e.
This is absorbed by the deformation of the diaphragm f inside. Further, an oil inlet k is provided in the oil passage in the accumulator e, and the vehicle height can be arbitrarily adjusted by letting pressurized oil in and out from the oil inlet k.

[Problem that the invention attempts to solve]

However, in the conventional hydraulic shock absorber shown in Fig. 4,
Since the damping valve j is installed in the middle of the oil path of the accumulator e, an extra space is required for the space of the accumulator e. Furthermore, since the damping valve j is installed in the accumulator e section, a damping force adjustment function is added. There was a problem that it was difficult to do.

Therefore, the present invention aims to save space by changing the conventional method of providing the damping force generating section in the accumulator section, and to make it possible to switch the damping force at will.

[Means for solving problems]

In this invention, a hollow piston rod is slidably inserted into a cylinder via a piston, and the piston partitions a rod side oil chamber and a head side oil chamber in the cylinder, and the rod side oil chamber and the head side oil chamber are separated. In a hydraulic shock absorber, the piston communicates with the oil chamber through a piston port provided in the piston, an accumulator is provided above the piston rod, and the oil chamber of the accumulator communicates with the head side oil chamber through the oil chamber in the piston rod. It is formed into an annular shape and its center is attached to the upper outer periphery of the piston rod, and a piston nut is fixed to the lower end of the piston rod.
A control valve is rotatably provided inside the piston nut, the control valve is connected to a control rod rotatably inserted into an oil chamber within the piston rod, and a port is provided on the outer periphery of the control valve. Corresponding ports are provided on the side of the piston nut, and the oil chamber in the piston rod is opened and closed to the head side oil chamber through each port, and furthermore, the oil chamber in the piston rod is opened and closed to the head side oil chamber at the lower end of the piston nut from the expansion side leaf valve and the compression side leaf valve. The piston rod is equipped with a damping valve and a non-return valve that opens during the compression stroke to open and close the piston rod internal oil chamber and the head side oil chamber.

[Effect]

In the case of an extension stroke, oil in the oil chamber on the rod side of the cylinder flows into the oil chamber on the head side, and at the same time, oil corresponding to the amount of movement of the piston rod flows from the accumulator to the oil chamber in the piston rod, the control valve, the port provided in the piston nut, and the damping valve. and flows to the head side oil chamber. At this time, the damping force is adjusted by appropriately rotating the control valve.

Conversely, in the case of the compression stroke, oil flows in the opposite direction through the passage that flowed during the extension stroke, and also flows from the non-return valve, and the damping force is adjusted in the same manner.

〔Example〕

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

FIG. 1 shows an embodiment in which a hollow piston rod 3 is inserted into a cylinder 2 housed in an outer shell 1 so as to protrude upward from the upper ends of the outer shell 1 and the cylinder 2. A piston 4 is fitted onto the outer periphery of the lower end of the piston rod 3, and an inner piston nut 5 and an outer piston nut 6 are attached, and a chamber 7 within the inner piston nut 5 is fitted.
has a rotatably built-in control valve 8,
Further, a damping valve 9 is provided inside the lower end of the outer piston nut 6, and is composed of ports a and b, and a growth side leaf valve 9a and a compression side leaf valve 9b provided at the outlet ends of each port a and b. 8 is an actuator (not shown) fixed to the lower end of a control rod 10 disposed at the axial center of the piston rod 3 and provided at the upper end of the piston rod 3.
This allows the control valve 8 to rotate via the control rod 10.

The control valve 8 has an inner chamber 11, as shown in the enlarged view of FIG. The inner piston nut 5 has a side portion thereof and a partition wall 5.
Ports 5b and 5c corresponding to the ports 8a and 8b are provided on the outer piston nut 6, respectively, and a port 6a is provided on the side of the outer piston nut 6 at a position corresponding to the port 5c. is always in communication with chamber 7,
The control valve 8 rotates and the side port 8
a and the corresponding port 5 of the piston nut 5
The damping force can be adjusted by connecting or cutting off communication with b. In this communication state, oil can flow between the oil chamber A in the piston rod 3 and the head side oil chamber B of the cylinder 2.
Also, oil can flow between the oil chamber A in the piston rod 3 and the head side oil chamber B through the damping valve 9, the port 8b on the ceiling of the control valve 8, and the port 5c on the partition wall 5a. The rod side oil chamber C and the head side oil chamber B of the cylinder 2 are communicated through a piston port 12 penetrating the piston 4.

Further, in the damping force generating section of the present invention, as a damping force generating mechanism, a port 13 that communicates between the inner chamber 11 of the control valve 8 and the head side oil chamber B is provided on the inner chamber 11 side thereof, which is closed during the extension stroke. A non-return valve 14 is provided that is pushed open during the compression stroke, and a spring 15 normally closes port 1.
Make sure it is pressed to the 3rd side.

On the other hand, on the outer periphery of the upper end of the piston rod 3, there is an annular accumulator 16 in which an annular oil chamber D and a gas chamber E are partitioned into inner and outer parts by a bellows 17.
is installed so that it is coaxial with the piston rod 3, and the oil chamber D in the annular accumulator 16 and the oil chamber A in the piston rod 3 are communicated through the port 18, so that the oil in both oil chambers A and D is Make it possible for them to come and go. Pressure oil can be supplied and discharged from the outside to the oil chamber D in the accumulator 16 through an oil passage 19, so that the vehicle height can be adjusted.

In addition, 20 is the seal of the piston rod 3, 21
is the nutkuru bracket, 22 is the bottom cap,
23 is the lower cap, 24 is the extension stopper, 25
is the drain plug.

When the hydraulic shock absorber of the present invention enters an extension stroke due to an impact while the vehicle is running, the oil in the rod-side oil chamber C of the cylinder 2 flows into the piston port 12 of the piston 4.
At the same time, oil corresponding to the amount of movement of the piston rod 3 flows from the oil chamber A in the piston rod 3 to the ports 5c, 8b, 8a,
Pass through 5b and 6a in this order and enter the head side oil chamber B.
At the same time, the oil enters the head side oil chamber B from the inner chamber 11 of the control valve 8 through the damping valve 9. When the oil in the oil chamber A in the piston rod 3 flows to the head side oil chamber B, the oil in the oil chamber D in the accumulator 16 flows into the oil chamber A in the piston rod 3 through the port 18.
, the bellows 17 is deformed and the volume of the gas chamber E increases. Further, at this time, the damping force can be switched and adjusted by appropriately rotating the control valve 8 and appropriately changing the position of the port 8a relative to the port 5b. In this case, for example, as shown in FIG.
By shifting the positions of the large diameter port 5b and the small diameter port 5b, by rotating the control valve 8, the port 8a of the control valve 8 can be moved to the three positions of the port 5b, large diameter, small diameter, and no port. By adjusting the port area, the port area can be switched in three stages.

Also, during the compression stroke, the oil in the head side oil chamber B of the cylinder 2 enters the rod side oil chamber C through the piston port 12, and the oil in the head side oil chamber B also flows in line with the oil flow during the extension stroke. flows in the opposite direction into the oil chamber A inside the piston rod 3. At this time, the oil in the oil chamber A in the piston rod 3 enters the oil chamber D in the accumulator 16 through the port 18, so the bellows 17 in the accumulator 16 is deformed, the volume of the gas chamber E decreases, and the gas The pressure in chamber E increases.

In the above, if the non-return valve 14 is provided, during the compression stroke, the oil in the head side oil chamber B passes through the port 13, pushes open the non-return valve 14, and enters the inner chamber 11 of the control valve 8. Since the oil enters the oil chamber A in the piston rod 3 through the ports 8b and 5c, further damping force can be generated.

Note that the present invention is not limited to the above-mentioned embodiments; for example, the accumulator 16 may be of a spherical type, and other various changes may be made without departing from the gist of the present invention. Of course.

[Effect of idea]

According to the present invention, there are the following effects.

The damping valve, which was conventionally provided in the accumulator, is provided in the piston nut in the cylinder, and the control valve and non-return valve are also incorporated in the piston nut, so the structure is compact and space can be saved.

Since the control valve is connected to the control rod inserted through the oil chamber of the piston rod, the damping force adjustment mechanism becomes compact and can be adjusted from the outside.

Since the accumulator is formed into an annular shape and its center is attached to the upper outer periphery of the piston rod, the accumulator is compact and does not protrude outwards, so it can be easily attached even in a small space, and space can be saved.

[Brief explanation of drawings]

Fig. 1 is a longitudinal sectional view showing an example of the hydraulic shock absorber of the present invention, Fig. 2 is an enlarged view of the part shown in Fig. 1, and Fig. 3 shows the damping force switching in three stages in the hydraulic shock absorber of the present invention. An example diagram, FIG. 4, is a schematic diagram of a conventional hydraulic shock absorber. 2...Cylinder, 3...Piston rod, 4...
...Piston, 5...Inner piston nut, 6...
Outer piston nut, 7...chamber, 8...
Control valve, 9... Damping valve, 11...
...inner room.

Claims (1)

[Scope of utility model registration request] A hollow piston rod is slidably inserted into the cylinder via a piston, and the piston divides the cylinder into a rod-side oil chamber and a head-side oil chamber, and the rod-side oil chamber and the head-side oil chamber are provided in the piston. In a hydraulic shock absorber, an accumulator is provided in the upper part of the piston rod, and the oil chamber of the accumulator is communicated with the head side oil chamber via the oil chamber in the piston rod. A piston nut is fixed to the lower end of the piston rod, a control valve is rotatably provided inside the piston nut, and the control valve is rotatably inserted into an oil chamber within the piston rod. A port is provided on the outer periphery of the control valve, and a corresponding port is provided on the side of the piston nut, and the oil chamber in the piston rod is connected to the head side oil through each port. A damping valve consisting of a compression side leaf valve and a compression side leaf valve is provided at the lower end of the piston nut, and a non-return valve that opens during the compression stroke is opened and closed in the piston rod inner oil chamber and the head side oil chamber. A hydraulic shock absorber featuring: