JPS6246924Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a shock absorber, and more specifically to a shock absorber in which a reservoir chamber is provided between an inner cylinder and an outer cylinder coaxially arranged with a space between them on the outside of the inner cylinder. In particular, the present invention relates to a shock absorber that is most suitable for being incorporated into a front wheel suspension system of an automobile.

Shock absorbers built into automobile suspension systems absorb shocks applied to the wheels during normal driving, providing a comfortable ride. On the other hand, when a large deceleration is applied to the vehicle body, such as when braking suddenly, the front of the vehicle body sinks, causing so-called nose dive.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a shock absorber that provides good cushioning during normal driving and prevents nose dive during braking.

Incidentally, a shock absorber used in an automobile suspension system has a hydraulic fluid reservoir chamber between an inner cylinder on which a piston connected to a piston rod slides and an outer cylinder coaxially arranged outside the inner cylinder. There is a type in which a free piston is slidably arranged in a single cylinder in addition to the piston connected to the piston rod, and an air chamber is formed between the free piston and the cylinder. In the former, the amount of liquid in the reservoir chamber is increased or decreased by the flow of hydraulic fluid generated between the inner cylinder and the reservoir chamber as the piston moves up and down, thereby absorbing the volume change due to the movement of the piston. In the latter case, the free piston moves up and down following the up and down movement of the piston to absorb volume changes. The present invention was devised by focusing on the fact that the former type causes a flow of hydraulic fluid within the reservoir chamber.

The shock absorber of the present invention has its upper and lower ends fixed to the inner circumferential surface of a mounting tube fitted into an outer tube or to the inner circumferential surface of an outer tube, and together with this inner circumferential surface, a fluid chamber is formed in a reservoir chamber. a diaphragm that opens into the reservoir chamber above the upper end of the diaphragm and below the lower end of the diaphragm; a check valve installed in the bypass pipe; and pressurizing means for supplying pressurized fluid to the fluid chamber. The diaphragm partitions the reservoir chamber into upper and lower parts when pressure fluid is supplied to the fluid chamber. Further, the check valve allows the hydraulic fluid to flow only from the upper reservoir chamber portion of the diaphragm to the lower reservoir chamber portion.

Embodiments of the present invention will be described below with reference to the accompanying drawings.

As shown in FIG. 1, the shock absorber of the present invention has an inner cylinder 10 and an outer cylinder 12 coaxially arranged outside the inner cylinder 10 with a space between the inner cylinder 10 and the outer cylinder 12. and the hydraulic fluid reservoir chamber 1.
This is the type marked 4. The upper end of the inner cylinder 10 and the outer cylinder 12 are fixed by a rod guide 16, a seal member 18, and a cover 20, which are arranged at the upper ends of the inner cylinder 10 and the outer cylinder 12. The lower part is fixed by the disposed foot valve mechanism 22 and bottom cover 24, and the inner cylinder 10 and the outer cylinder 12 maintain a predetermined distance, and the reservoir chamber 1
4 is formed. Compressed gas is sealed in this reservoir chamber 14 together with the working fluid. The outer cylinder 12 is connected to a suspension arm at its lower end.

A piston 26 is disposed so as to be able to slide on the inner peripheral surface of the inner cylinder 10, and a piston rod 28 connected to the piston 26 at its lower end projects to the outside through the rod guide 16, the seal member 18 and the cover 20. and is connected to the vehicle body at its upper end. The liquid chambers 30 and 32 in the inner cylinder 10, which are partitioned vertically by the piston 26, communicate with each other via a valve mechanism 34 provided on the piston 26, while the lower liquid chamber 32 and the reservoir chamber 14 are in communication with each other via the foot valve mechanism 22 and passage 36. With the above configuration, when the piston 26 moves up and down within the inner cylinder 10, a flow of hydraulic fluid occurs between the liquid chamber 32 and the reservoir chamber 14, and the amount of liquid within the reservoir chamber 14 increases or decreases.

A mounting cylinder 38 is fitted into the outer cylinder 12, and a lower end of the mounting cylinder 38 is fixed to the bottom cover 24. As shown in Figure 2, the mounting tube 3
The upper and lower ends 42 and 43 of the diaphragm 40 are fixed to the inner circumferential surface 39 of the diaphragm 40 by ring-shaped caulking members 44, respectively, and the diaphragm 40, together with the inner circumferential surface 39, forms a fluid chamber 46 in the reservoir chamber 14.
is depicted. This diaphragm 40 is made of rubber, and when pressure fluid is supplied to the fluid chamber 46, it expands inward and comes into close contact with the outer circumferential surface 11 of the inner cylinder 10, and partitions the inside of the reservoir chamber 14 into upper and lower parts. Cut off the flow. The diaphragm 40 is connected to the passageway 36.
installed in a location that does not block the

A bypass pipe 48 is attached to the outer cylinder 12 in a liquid-tight manner. This bypass pipe 48 opens into the reservoir chamber 14 above the upper end 42 of the diaphragm 40 and below the lower end 43. As a result, the fluid chamber 46
Even if pressure fluid is supplied to the reservoir chamber 14 and the diaphragm 40 partitions the reservoir chamber 14 into upper and lower parts, the reservoir chamber 14
are in communication via a bypass pipe 48.

A check valve 50 is installed in the bypass pipe 48. The check valve 50 allows the hydraulic fluid to flow from the reservoir chamber section 13 located above the diaphragm 40 to the reservoir chamber section 15 located below, but prevents the opposite flow. The check valve 50 may be installed at any location other than the inlet of the bypass pipe 48, as in the illustrated example.

A pressurizing means 52 is communicated with the fluid chamber 46 .
In the illustrated example, the pressurizing means 52 includes a cylinder 54 and a piston 56 that slides within the cylinder 54, and a connector 58 is attached to the output side of the cylinder 54. This connector 58 is connected to the outer cylinder 12
The outer cylinder 12 and the connector 58 are fitted into a hole 60 provided in the outer cylinder 12 and a hole 62 provided in a corresponding position in the mounting cylinder 38, and the outer cylinder 12 and the connector 58 are welded. On the other hand, the cylinder 54
The input side of is connected via a pipe 64 to, for example, a booster of a braking system of an automobile.

The cylinder 54 is filled with fluid, such as brake oil. This brake oil also flows into the fluid chamber 46. A coil spring 66 is further disposed within the cylinder 54 and biases the piston 56 toward the input side of the cylinder 54 . As shown in FIG.
When the brake oil is biased toward the input side, part of the brake oil filled in the fluid chamber 46 is sucked into the cylinder 54, and the diaphragm 40 becomes relaxed and separated from the outer circumferential surface 11 of the inner cylinder 10. , the volumes of the liquid chamber 55 and the fluid chamber 46 of the cylinder 54 are determined.

When the automobile is braked while the vehicle is running, the pressure generated in the braking device acts on the input side of the pressurizing means 52, pushing the piston 56 against the coil spring 66 toward the output side. As a result, high pressure is generated within the liquid chamber 55 of the cylinder 54, and the fluid chamber 46 is placed under high pressure, so that the diaphragm 40 protrudes inward as shown in FIG. Face 11
Close to. As a result, the inside of the reservoir chamber 14 is partitioned into upper and lower sections. Moreover, in this case, the bypass pipe 48
The check valve 50 provided in the diaphragm 40 does not allow the hydraulic fluid to flow from the lower reservoir chamber portion 15 to the upper reservoir chamber portion 13. Therefore, since the flow of the hydraulic fluid is blocked, the piston 2
It provides a large resistance to the movement of 6 and suppresses nose dive. When the brake is released, the pressurizing means 5
The second piston 56 is connected to the second piston 56 by a coil spring 66.
The diaphragm 40 returns to the position shown in the figure.
is relaxed, and the inside of the reservoir chamber 14 becomes in the same state as the reservoir chamber of a normal shock absorber, providing a buffering effect during normal running.

If the braking condition is maintained, the front part of the vehicle will rise and return to its original position after the nose dive, and the shock absorber will extend. As this expansion occurs, the hydraulic fluid in the upper reservoir chamber section 13 of the diaphragm 40 passes through the bypass pipe 48 and the check valve 50 to the lower reservoir chamber section 15 and flows into the fluid chamber 32 .

In the above example, the diaphragm is fixed to the inner circumferential surface of the mounting tube fitted into the outer tube, and forms a fluid chamber together with the inner circumferential surface. Alternatively, the diaphragm may be directly fixed to the inner circumferential surface of the outer cylinder and form a fluid chamber together with the inner circumferential surface of the outer cylinder. In addition, although an independent pressure means is provided,
For example, the output from the booster of the braking device may be led directly to the fluid chamber. The pressurizing means in this case is a booster.

According to the present invention, the diaphragm placed in the reservoir chamber is brought into close contact with the outer peripheral surface of the inner cylinder by the pressure fluid supplied during braking of the automobile, and partitions the reservoir chamber into upper and lower parts, so that nose dive does not occur. Further, during normal driving, the cushioning effect is performed well, so the riding comfort is not deteriorated. Furthermore, when the front part of the car rises after a nose dive and the shock absorber expands accordingly, even if the brake is maintained and the reservoir chamber is shut off by the diaphragm, the hydraulic fluid will flow through the bypass pipe. Then, by the action of the check valve, it flows into the liquid chamber below the piston. For this reason, if there is no bypass pipe or check valve, air bubbles will be sucked into the liquid chamber.
In subsequent use, it is possible to effectively prevent the occurrence of a situation that would lead to insufficient damping force.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of the shock absorber of the present invention, showing a state in which the diaphragm is tensioned to partition a reservoir chamber, and FIG. 2 is an enlarged sectional view of the main part, showing a state in which the diaphragm is relaxed. 10: Inner cylinder, 11: Outer surface, 12: Outer cylinder, 1
3: Upper reservoir chamber part, 14: Reservoir chamber,
15: Lower reservoir chamber part, 26: Piston,
28: Piston rod, 38: Mounting tube, 39:
Inner peripheral surface, 40: Diaphragm, 46: Fluid chamber, 4
8: bypass pipe, 50: check valve, 52: pressurizing means, 54: cylinder, 56: piston.

Claims (1)

[Scope of utility model registration request] The shock absorber has a hydraulic fluid reservoir chamber between an inner cylinder and an outer cylinder coaxially arranged outside the inner cylinder with a space therebetween, and the inner cylinder of the mounting cylinder fitted with the outer cylinder has a hydraulic fluid reservoir chamber. A diaphragm whose upper and lower ends are fixed to the circumferential surface or to the inner circumferential surface of the outer cylinder, and which together with the inner circumferential surface define a fluid chamber within the reservoir chamber, into which pressurized fluid is supplied. a diaphragm that is in close contact with the outer peripheral surface of the inner cylinder to partition the reservoir chamber into upper and lower parts; a bypass pipe that opens into the reservoir chamber above the upper end of the diaphragm and below the lower end of the diaphragm; A check valve is installed in the bypass pipe and allows the hydraulic fluid to flow only from the reservoir chamber above the diaphragm to the reservoir chamber below; and pressurizing means for supplying fluid.