JPS6228336B2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a shock absorber.

FIG. 1 is a side view showing a shock absorber 1 used in a general two-wheeled motor vehicle. It is interposed between the front wheel 5 and the front wheel 5. The shock absorber 1 uses a spring to buffer vibrations caused by unevenness of the road surface, and also suppresses and damps vertical vibrations of the springs by using oil flow resistance.

FIGS. 2 and 3 are cross-sectional views showing the internal structure of a conventional shock absorber.
1 is slidably inserted into the outer tube 12, and a hollow rod 13, which is vertically installed at the inner bottom of the outer tube 12, is inserted into the end surface 1 of the inner tube 11.
1A and is loosely inserted into the inner tube 11. An auxiliary piston 14 is formed at the tip of the hollow rod 13, a spring 15 is interposed between the other end surface of the inner tube 11 and the auxiliary piston 14, and an oil reservoir 16 formed by the inner tube 11 is filled with oil. is stored. A pressure chamber 17 defined by the inner tube 11, the hollow rod 13, and the auxiliary piston 14 is communicated with the oil reservoir chamber 16 through the throttle hole 18, and the inner tube 11 and outer tube 12 of this shock absorber are mutually connected. It is possible to generate damping force during the extension stroke.

During the compression stroke in which the inner tube 11 and the outer tube 12 of the conventional shock absorber mutually contract, the oil filling the chamber 19 flows into the pressure chamber 17 via the check valve 20, and excess oil flows into the pressure chamber 17 through the check valve 20. Oil is led from the through hole 21 to the oil reservoir chamber 16 through the hollow part of the hollow rod 23. As the compression stroke further progresses, the lock piece 22 integrated at the tip of the inner tube 11 fits into the lock taper 23 integrated at the bottom of the outer tube 12, and the outer tube 12, the lock tube 22, and the lock taper 23 engage By forming a hydraulic lock chamber 24 as shown in FIG. 3 and trapping oil in this hydraulic lock chamber 24,
The compressive resistance force generated between the inner tube 11 and the outer tube 12 is rapidly increased to prevent the occurrence of impact due to bottom collision between the inner tube 11 and the outer tube 12.

However, in such a conventional shock absorber, as the compression process progresses, a large compression resistance force suddenly occurs at the end of the compression process.
When such a shock absorber is applied to a vehicle, for example, there is a problem that a good riding feeling cannot be ensured.

The present invention has been made in view of the above-mentioned conventional problems, and an object of the present invention is to provide a shock absorber that can smoothly alleviate the impact caused by the bottom collision between the inner tube and the outer tube.

In order to achieve the above object, the present invention includes a sliding contact portion extending over substantially the entire length of an inner tube, which is slidably inserted into a sliding contact portion extending over substantially the entire length of the outer tube, and a hollow rod fixed to the inner bottom of the outer tube is inserted into the inner tube. The oil reservoir chamber formed inside the inner tube and the chamber formed inside the outer tube communicate with each other through a through hole and a hollow part provided in the hollow rod, and an oil reservoir chamber formed inside the inner tube and a chamber formed inside the outer tube communicate with each other through a through hole and a hollow part provided in the hollow rod. The pressure chamber is communicated with the oil reservoir chamber through a throttle hole, and the pressure chamber is connected to the inside of the outer tube through a check valve that is provided in the inner tube and opens during a compression stroke in which the inner tube and the outer tube mutually contract. A buffer that communicates with the formed chamber and generates a damping force during the extension stroke by discharging the oil in the pressure chamber through the throttle hole into the oil reservoir chamber during the extension stroke when the inner tube and outer tube mutually extend. In the device, the outer circumference of the tip of the inner tube inserted into the outer tube is the small outer diameter part, the inner circumference of the bottom side of the outer tube is the small inner diameter part, and the communication hole of the check valve provided in the inner tube is the small outer diameter part of the inner tube. In a first stage in which the inner tube is opened, the compression stroke approaches the end end, and the small outer diameter portion of the inner tube fits into the small inner diameter portion of the outer tube,
A second stage in which a sealed first hydraulic lock chamber is formed between the inner tube and the outer tube, and when the compression stroke approaches the end end, the communication hole of the check valve provided in the inner tube is closed to the small inner diameter portion of the outer tube. A sealed second hydraulic lock chamber is formed between the inner tube and the outer tube.

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

4 to 6 are cross-sectional views showing different operating states of a shock absorber as an embodiment of the present invention. The inner tube 31 is slidably inserted into the outer tube 32 via the sliding contact portion 31A and the sliding contact portion 32A. The outer circumference on the tip side of the inner tube 31 is a small outer diameter part 31B, and the inner circumference on the bottom side of the outer tube 32 is a small inner diameter part 32B.
The small outer diameter portion 31B can be fitted into the small inner diameter portion 32B.

A hollow rod 33, which is vertically provided at the inner bottom of the outer tube 32, passes through the distal end surface of the inner tube 31 and is loosely inserted into the inner tube 31, and an auxiliary piston 34 is disposed at the distal end of the hollow rod 33. A spring 35 is compressably inserted between the inner tube 31 and the auxiliary piston 34,
The oil reservoir chamber 36 within the inner tube 31 is filled with oil at a predetermined level. The oil in the oil reservoir chamber 36 can flow through the hollow portion of the hollow rod 33 and the through hole 37 into a chamber 38 defined by the tip of the inner tube 31, the outer tube 32, and the hollow rod 33. The pressure chamber 39 defined by the inner tube 31, the hollow rod 33, and the auxiliary piston 34 includes the inner tube 31 of this shock absorber.
During the compression stroke in which the inner tube 31 and the outer tube 32 mutually contract, oil is led from the chamber 38 through the check valve 40 and the communication hole 40A, and the oil led to the pressure chamber 39 is transferred to the inner tube 31 and the outer tube 32 of this shock absorber. are discharged to the oil reservoir chamber 36 side through the throttle hole 41 during the extension stroke in which they mutually extend, making it possible to generate a damping force during the extension stroke. Note that the communication hole 40A is connected to the small outer diameter portion 31 of the inner tube 31.
It opens at B.

Furthermore, inner tube 31 and outer tube 3
At the end of the compression stroke, a closed space consisting of a first hydraulic lock chamber 42 shown in FIG. 5 and a second hydraulic lock chamber 43 shown in FIG. can be formed in two stages. That is, the compression stroke progresses, and the small outer diameter portion 31B of the inner tube 31 becomes the outer tube 32.
5, the first hydraulic lock chamber 42 is inserted between the distal end surface of the inner tube 31 and the bottom of the outer tube 32.
is formed, and when the compression stroke further progresses to a recompressed state, the communication hole 40A is closed by the small inner diameter portion 32B of the outer tube 32, and the small outer diameter portion 31B of the inner tube 31 and the sliding contact portion 32A of the outer tube 32 are closed. A second hydraulic lock chamber 43 is formed between the two.

Next, the operation of the above embodiment will be explained. During the extension stroke of the shock absorber, oil in the oil reservoir chamber 36 flows into the chamber 38 through the hollow portion of the hollow rod 33 and the through hole 37, and during this extension stroke, the check valve 40 is closed. Therefore, the oil in the pressure chamber 39 is discharged to the oil reservoir chamber 36 side through the throttle hole 41, and generates a damping force during expansion. During the compression stroke of the shock absorber, oil in the chamber 38 flows into the pressure chamber 39 via the communication hole 40A and the check valve 40, and excess oil flows from the communication hole 37 through the hollow part of the hollow rod 33. and is guided to the oil sump chamber 36. As the compression stroke progresses and approaches its end, the small outer diameter portion 31B of the inner tube 31 fits into the small inner diameter portion 32B of the outer tube 32, as shown in FIG. A first hydraulic lock chamber 42 is formed to slightly increase the compression resistance generated between the inner tube 31 and the outer tube 32. In addition, at the stage where the first hydraulic lock chamber 42 is formed, the oil surrounded between the small outer diameter portion 31B of the inner tube 31 and the sliding contact portion 32A of the outer tube 32 flows through the communication hole 40A and the check valve. 4
0 and can flow into the pressure chamber 39 side.
When the compression stroke further advances and reaches the maximum compression state, as shown in FIG. 6, the communication hole 40A is closed by the small inner diameter portion 32B of the outer tube 32, and a second A hydraulic lock chamber 43 is formed to rapidly increase the compressive resistance force generated between the inner tube 31 and the outer tube 32, and to reduce the impact caused by the bottom end of the inner tube 31 colliding with the bottom of the outer tube 32.

According to the above embodiment, a certain amount of shock during the compression stroke is alleviated by the first hydraulic lock chamber 42, and a larger shock is relieved by the first hydraulic lock chamber 42 and the second hydraulic lock chamber 43. Since the hydraulic lock chamber is formed in two stages, it is possible to smoothly alleviate the impact caused by the bottom collision between the inner tube 31 and the outer tube 32.

As described above, in the present invention, the sliding contact portion extending over approximately the entire length of the inner tube is slidably inserted into the sliding contact portion extending over the approximately entire length of the outer tube, and the hollow rod fixed to the inner bottom of the outer tube is inserted into the inner tube. The oil reservoir chamber formed inside the inner tube and the chamber formed inside the outer tube are communicated through a through hole and a hollow part provided in the hollow rod, and the pressure chamber formed between the inner tube and the hollow rod is connected. The pressure chamber is formed inside the outer tube via a check valve that communicates with the oil reservoir chamber through a throttle hole and is provided in the inner tube and opens during a compression stroke in which the inner tube and the outer tube mutually contract. A shock absorber that communicates with a chamber and generates a damping force during an extension stroke by discharging oil in the pressure chamber into an oil reservoir chamber through a throttle hole during an extension stroke in which the inner tube and the outer tube mutually extend;
The outer periphery of the inner tube on the tip side inserted into the outer tube is a small outer diameter part, the inner periphery of the bottom side of the outer tube is a small inner diameter part, and the communication hole of the check valve provided in the inner tube is opened in the small outer diameter part of the inner tube, In the first stage when the compression stroke approaches the end and the small outer diameter portion of the inner tube fits into the small inner diameter portion of the outer tube, a sealed first hydraulic lock chamber is formed between the inner tube and the outer tube, and the compression stroke As the stroke approaches the end, the communication hole of the check valve provided in the inner tube is closed to the small inner diameter part of the outer tube.
Since the sealed second hydraulic lock chamber is formed between the inner tube and the outer tube in this step, there is an effect that the impact against the bottom collision between the inner tube and the outer tube can be smoothly alleviated.

[Brief explanation of the drawing]

Figure 1 is a partial side view showing a shock absorber used in general motorcycles, Figure 2 is a cross-sectional view showing the internal structure of a conventional shock absorber, and Figure 3 is the same as that of Figure 2. FIG. 4 is a sectional view showing the internal structure of the shock absorber according to the present invention, and FIGS. 5 and 6 are sectional views showing different operating states of FIG. 4. 31... Inner tube, 32... Outer tube, 39... Pressure chamber, 42... First hydraulic lock chamber, 43... Second hydraulic lock chamber.

Claims (1)

[Claims] 1. A sliding contact portion extending over approximately the entire length of the inner tube is slidably inserted into a sliding contact portion extending over approximately the entire length of the outer tube, and a hollow rod fixed to the inner bottom of the outer tube is inserted into the inner tube to form an oil reservoir inside the inner tube. The chamber and the chamber formed inside the outer tube communicate with each other through a through hole provided in the hollow rod and the hollow part, and the pressure chamber formed between the inner tube and the hollow rod is connected to the oil sump through a throttle hole. The pressure chamber is communicated with a chamber formed inside the outer tube through a check valve that is provided in the inner tube and opens during a compression stroke in which the inner tube and the outer tube mutually contract. In a shock absorber that generates a damping force during the extension stroke by discharging the oil in the pressure chamber into the oil reservoir chamber through the throttle hole during the extension stroke in which the inner tube and the inner tube extend each other, the tip is inserted into the outer tube of the inner tube. The side outer periphery is a small outer diameter part, the bottom inner periphery of the outer tube is a small inner diameter part, a communication hole of a check valve provided in the inner tube is opened in the small outer diameter part of the inner tube, and the compression stroke approaches the end end. , in a first stage in which the small outer diameter portion of the inner tube fits into the small inner diameter portion of the outer tube, a sealed first hydraulic lock chamber is formed between the inner tube and the outer tube, and the compression stroke further approaches the end end; A shock absorber characterized in that, in a second stage in which a communication hole of a check valve provided in the inner tube is closed to a small inner diameter portion of the outer tube, a sealed second hydraulic lock chamber is formed between the inner tube and the outer tube.