JPH06239126A - Hydraulic buffer - Google Patents

Abstract

PURPOSE:To reduce the damping force in a normal running condition, and to improve the riding feeling, by providing a disk valve to control the flow of a communicating oil between a reservoir chamber and a cylinder chamber so as to generate a damping force, and controlling the opening of the disk valve according to the braking hydraulic pressure in a braking condition. CONSTITUTION:In a normal running condition, a plunger 21 is moved to the bottom side of a cylinder bore 20 by the force of a spring 25, a projection 24 is abutted to the bottom of the cylinder bore 20, and the stopper 23 of the plunger 21 is separated from the disk valve 17 of a base valve 9. As a result, the valve 17 is at the maximum valve opening condition so as to reduce the damping force. On the other hand, in the braking condition of the vehicle, the hydraulic pressure of a braking circuit is operated to a fluid pressure chamber 20 through a pipe line 28, and the plunger 21 is moved to the base valve 9 side against the spring 25 by its hydraulic pressure. Consequently, the disk valve 17 is abutted to the stopper 32 before abutted to a washer 32, and thereby, its bending margin is regulated, the opening at the maximum valve opening condition is reduced, and the damping force is increased.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic shock absorber mounted on a suspension system of a vehicle such as an automobile.

[0002]

2. Description of the Related Art A conventional hydraulic shock absorber mounted on a suspension system of a vehicle will be described with reference to FIG.

As shown in FIG. 4, the hydraulic shock absorber 1 has a double cylinder structure having an inner cylinder 2 forming a cylinder and an outer cylinder 3 provided outside the inner cylinder 2. A cylinder upper and lower chamber, which will be described later, is formed in the inner cylinder 2, and a reservoir chamber 2c is formed between the inner cylinder 2 and the outer cylinder 3. A piston 4 is slidably fitted in the inner cylinder 2, and the interior of the inner cylinder 2 is defined by the piston 4 into a cylinder upper chamber 2a and a cylinder lower chamber 2b. One end side of a piston rod 5 is connected to the piston 4 by a nut 6, and the other end side of the piston rod 5 penetrates a rod guide 7 and a seal member 8 provided at the upper ends of the inner cylinder 2 and the outer cylinder 3. And extended to the outside of the cylinder. At the lower end of the inner cylinder 2,
A base valve 9 is provided, and the cylinder lower chamber 2b and the reservoir chamber 2c communicate with each other via the base valve 9. The cylinder upper chamber 2a and the cylinder lower chamber 2b are filled with oil liquid, and the reservoir chamber 2c is filled with oil liquid and pressurized or atmospheric pressure gas.

The piston 4 is provided with an extension-side oil liquid passage 10 and a compression-side oil liquid passage 11 which connect the cylinder upper chamber 2a and the cylinder lower chamber 2b. In the piston 4, the disc valve 12 and the compression-side oil liquid passage 11 that allow the oil liquid to flow from the cylinder upper chamber 2a side to the cylinder lower chamber 2b side of the extension-side oil liquid passage 10 to generate a damping force. A check valve 13 is provided which allows only the oil liquid to flow from the cylinder lower chamber 2b side to the cylinder upper chamber 2a side.

The base valve body 9a of the base valve 9 is provided with an extension side communication passage 14 and a compression side communication passage 15 for communicating the cylinder lower chamber 2b with the reservoir chamber 2c. Then, the base valve body 9a includes a check valve 16 that allows only the flow of the oil liquid from the reservoir chamber 2c side of the extension side communication passage 14 to the cylinder lower chamber 2b side and the cylinder lower chamber 2b side of the compression side communication passage 15 A disk valve 17 is provided which allows the oil liquid to flow from the side to the reservoir chamber 2c side to generate a damping force.

The operation of the hydraulic shock absorber 1 configured as described above will be described below.

During the extension stroke of the piston rod 5, the oil liquid in the cylinder upper chamber 2a flows through the extension side oil liquid passage 10 to the cylinder lower chamber 2b as the piston 4 moves, and the disc valve 12 bends and opens. , The damping force is generated according to the opening. At this time, the oil liquid corresponding to the piston rod 5 withdrawing from the inner cylinder 2 opens the check valve 16 of the base valve 9 from the reservoir chamber 2c and flows through the extension side communication passage 14 to the cylinder lower chamber 2b.

During the compression stroke of the piston rod 5, as the piston 4 moves, the oil liquid in the cylinder lower chamber 2b opens the check valve 13 and flows through the compression side oil liquid passage 11 to the cylinder upper chamber 2a. At this time, the oil liquid corresponding to the piston rod 5 entering the inner cylinder 2 flows from the cylinder lower chamber 2b through the contraction side communication passage 15 of the base valve 9 to the reservoir chamber 2c, and the disc valve 17 bends to open. , The damping force is generated according to the opening.

In this way, the damping force is generated by the disc valve 12 of the piston 4 during the extension stroke of the piston rod 5, and the damping force is generated by the disc valve 17 of the base valve 9 during the contraction stroke. The volume change in the inner cylinder 2 due to the expansion and contraction of the piston rod 5 is absorbed by the compression and expansion of the gas in the reservoir chamber 2c.

[0010]

By the way, in the conventional hydraulic shock absorber 1 described above, when the opening degree of the disc valves 12 and 17 at the time of maximum opening is set to be large, the damping force becomes small and the riding comfort during normal running is improved. improves. However, in such a case, the posture change (nose dive) cannot be obtained during braking because sufficient damping force cannot be obtained against the movement of the vehicle body load.
Causes a problem that becomes large.

The present invention has been made in view of the above points, and an object of the present invention is to provide a hydraulic shock absorber capable of increasing the damping force during braking.

[0012]

The hydraulic shock absorber of the present invention comprises:
In order to solve the above problems, a cylinder in which an oil liquid is sealed, a piston slidably fitted in the cylinder to define two chambers in the cylinder, and one end of the piston is connected to the piston. A base valve main body having a piston rod having the other end extended to the outside of the cylinder, a reservoir chamber in which oil liquid and gas are sealed, and a communication passage communicating the reservoir chamber and one chamber in the cylinder. A disc valve that controls the flow of the oil liquid in the communication passage of the base valve body to generate a damping force; and a disc valve that is disposed facing the disc valve and that is moved by the hydraulic pressure of the brake during braking to move the disc valve. It is characterized by comprising a plunger that regulates the opening degree.

[0013]

With this structure, during braking, the hydraulic pressure of the brake moves the plunger to regulate the opening of the disc valve, so that the damping force increases.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the drawings. Since the present embodiment is different from the conventional example shown in FIG. 4 only in the base valve portion, the same members as those shown in FIG. 4 are designated by the same reference numerals, and only the different portions will be described in detail. explain.

As shown in FIGS. 1 and 2, the hydraulic shock absorber
Reference numeral 18 denotes a cylinder lower chamber 2b that seals the outer cylinder 2 at the end of the outer cylinder 2 and
A substantially bottomed cylindrical plug 19 forming a passage that connects the reservoir chamber 2c and the reservoir chamber 2c is screwed. The plug 19 is provided with a cylinder bore 20 that opens so as to face the disc valve 17 of the base valve 9, and a plunger 21 is slidably fitted in the cylinder bore 20. Base valve body 9a
An annular retainer 22 is interposed between the plug 19 and the plug 19 to fix the base valve body 9a and the plunger.
The movement of 21 toward the base valve 9 side is restricted. The plunger 21 is provided with a cylindrical stopper portion 23 facing the disc valve 17 of the base valve 9. Also,
On the back side of the stopper 23 of the plunger 21,
Projection 24 that restricts the movement of the cylinder bore 20 of 21 to the bottom side
Is provided. A return spring 25 is interposed between the plunger 21 and the retainer 22 to bias the plunger 21 toward the bottom of the cylinder bore 20. Reference numeral 26 in the figure denotes a seal member that seals between the cylinder bore 20 and the plunger 21.

The plug 19 is provided with an oil liquid passage 27 which communicates with a hydraulic chamber 20a formed on the back side of the plunger 21 in the cylinder bore 20. A pipe 28 communicating with a hydraulic circuit (not shown) of the brake of the vehicle is connected to the oil liquid passage 27 by a joint 29 so that the hydraulic pressure of the brake hydraulic circuit is introduced into the hydraulic chamber. Has become. In the figure, 30 is a bleeder plug for bleeding air from the hydraulic chamber 20a and the conduit 28.

The operation of this embodiment having the above-mentioned structure will be described below.

Similar to the conventional example shown in FIG. 4, a damping force is generated by the disc valve 12 of the piston 4 during the expansion stroke of the piston rod 5, and the base valve 9 during the compression stroke.
A damping force is generated by the disc valve 17 of. Also,
During braking, the hydraulic pressure generated in the hydraulic circuit of the brake is
And acts on the hydraulic chamber 20a via.

During normal running of the vehicle (state without braking)
2, the hydraulic pressure in the hydraulic chamber of the brake is not generated and the hydraulic pressure in the hydraulic chamber 20a is low. Therefore, as shown in FIG. 2, the plunger 21 is moved to the bottom side of the cylinder bore 20 by the elastic force of the return spring 25. , The projection 24 is in contact with the bottom of the cylinder bore 20, and the stopper 23 of the plunger 21
Is sufficiently separated from the disc valve 17 of the base valve 9. Therefore, the bending margin of the disc valve 17, that is, the opening degree when the valve is opened at maximum is determined by the thickness of the retainer 31 and the washer.
Since the disc valve 17 can be bent until it contacts the washer 32 depending on the diameter of 32, the opening degree at the time of maximum valve opening becomes large and the damping force becomes small.

During braking of the vehicle, the hydraulic pressure of the hydraulic circuit of the brake acts on the hydraulic chamber 20a via the conduit 28, and this hydraulic pressure causes the plunger 21 to act on the elastic force of the return spring 25 as shown in FIG. It moves to the base valve 9 side against, and the stopper portion 23 approaches the disc valve 17. As a result, the disc valve 17 contacts the stopper portion 32 before it comes into contact with the washer 32, so that the amount of bending is restricted, so that the opening degree at the time of maximum valve opening becomes small and the damping force becomes large.

In this way, by restricting the opening of the disc valve 17 at the time of maximum opening during braking, it is possible to increase the damping force on the compression side and suppress the posture change of the vehicle body. Ride comfort can be improved by setting a small damping force. Especially the hydraulic shock absorber
By mounting 18 on the suspension device on the front wheel side of the vehicle, the nose dive during braking can be effectively suppressed.

In general, the wheels and the brake caliper are attached to the lower end side of the hydraulic shock absorber 18, and the hydraulic circuit of the brake is connected to the brake caliper from the vehicle body near the lower end of the hydraulic shock absorber 18. Therefore, in this embodiment,
Since the line 28 is connected to the lower end of the hydraulic shock absorber 18, the line 28
Since the brake pipe can be shortened, the brake pipe can be easily routed, and the possibility of pipe damage or the like is reduced.

In this embodiment, the disc valve is used to generate the damping force of the valve characteristic. However, the expansion side oil liquid passage 10 of the piston 4 and the contraction side oil liquid passage 15 of the base valve 9 are always communicated. It is also possible to provide an orifice passage that allows the damping force of the orifice characteristic to be obtained in addition to the valve characteristic.

[0024]

As described above in detail, according to the hydraulic shock absorber of the present invention, during braking, the plunger moves due to the hydraulic pressure of the brake to regulate the opening of the disc valve, so that the damping force increases. As a result, a change in the posture of the vehicle during braking is suppressed, so that the damping force during normal traveling can be set to be small and the riding comfort can be improved.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of an embodiment of the present invention.

FIG. 2 is an enlarged view of a main part showing a state in which braking is not performed in the device of FIG.

3 is an enlarged view of an essential part showing a state of the device of FIG. 1 during braking.

FIG. 4 is a vertical sectional view of a conventional hydraulic shock absorber.

[Explanation of symbols]

 2 Inner cylinder (cylinder) 2a Cylinder upper chamber 2b Cylinder lower chamber 2c Reservoir chamber 4 Piston 5 Piston rod 9a Base valve body 15 Contraction side communication passage (communication passage) 17 Disc valve 21 Plunger

Claims (1)

[Claims] 1. A cylinder in which oil liquid is sealed, a piston slidably fitted in the cylinder to define two chambers in the cylinder, one end of which is connected to the piston and the other end of which is A piston rod extended to the outside of the cylinder,
A base chamber having a reservoir chamber filled with oil and gas, a communication passage communicating the reservoir chamber with one of the chambers in the cylinder, and a flow of oil in the communication passage of the base valve body is controlled. A disc valve that generates a damping force, and a plunger that is arranged so as to face the disc valve and that is moved by the hydraulic pressure of the brake during braking to regulate the opening degree of the disc valve. Hydraulic shock absorber.