JPS6014220B2 - hydraulic shock absorber - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION A conventional hydraulic shock absorber used in a front fork of a two-wheeled vehicle has a constant damping force regardless of its extended or contracted position.

For this reason, when the degree of compression of the shock absorber is large and the reaction force of the suspension spring is large, it will expand rapidly, and when the compression temperature is small and the reaction force of the spring is 4. , there was a drawback that good Qin Xin et al. could not be obtained. The present invention provides a hydraulic shock absorber that does not have these drawbacks. FIG. 1 is a longitudinal sectional view of an embodiment of the present invention, in which oil seals 3 are provided at the entrance ends of bottomed cylindrical outer cylinders 1 and 2, and the opening ends are arranged to face each other. Inner cylinder 4
Numashiki freely competes at both ends.

Further, pipes 5 and 6 are installed in the bottom surfaces of the outer cylinders 1 and 2, respectively, and pistons 7 and 8 formed at their tips are slidably fitted inside the inner cylinder 4. Check valves 9 and 10 are provided at both ends of the inner cylinder 4, which open when the buffer is compressed and close when the buffer is expanded, and orifices 11 and 12 are provided at appropriate positions near the tips of the pipes 5 and 6, and orifices 11 and 12 are provided at the base. Sufficiently large oil holes 13 and 14 are formed. Further, a spring 15 is stretched between the pistons 7 and 8 to press the outer cylinders 1 and 2 apart, and between the piston 7 and the inner cylinder 4, the inner cylinder is pressed in the direction of the outer cylinder 1. A spring 16 is tensioned. In addition, a sufficiently strong buffer spring 17 is provided at the bottom of the piston 8,
An annular cushioning rubber seat 18 is attached to the bottom surface of the outer cylinder 1, and guides 19, 20 are attached to the upper end of the inner cylinder 4 and the opening of the outer cylinder 1.
The outer cylinders 1 and 2 and the inner cylinder 4 are filled with oil 21. In the above-mentioned hydraulic shock absorber, when the front part of a two-wheeled vehicle is suspended on the outer tube 1 and the front wheel is tied to the outer section 2, when the front wheel runs onto a convex part of the road surface, the spring 15
is compressed and the outer segment 2 moves upward.

In this case, since the inner cylinder 4 is pressed toward the outer cylinder 1 by the spring 16, it rises together with the outer cylinder 2, and its upper end abuts against the rubber seat 18 of the outer cylinder 1 as shown in FIG. Therefore, next, only the outer cylinder 2 rises as shown in FIG. Further, when the elasticity of the spring IS starts the extension stroke from the above-mentioned state, first only the outer cylinder 2 descends, and the lower end of the inner cylinder 4 moves into the buffer 1 imitation 17.
When the inner cylinder 4 and the outer cylinder 2 hit, the inner cylinder 4 and the outer cylinder 2 simultaneously descend and return to the state shown in FIG. In such an operation, during the stroke in which the outer cylinder 2 and the inner cylinder 4 simultaneously rise, the check valve 9 opens and oil flows into the upper part of the piston 7, and the shock absorber is easily compressed with a small damping force.

Also, the upper end of the inner cylinder 4 hits the bottom surface of the outer cylinder 1, and the outer cylinder 2
During the stroke in which the piston 8 is raised, the check valve 10 opens and the piston 8
Oil flows into the lower part of the shock absorber, and in this case, a somewhat large damping force is generated, suppressing the compression of the shock absorber. Next, due to the elasticity of the spring 15, the outer cylinder 2 enters an extension stroke, and during the downward stroke, the check valve 10 closes, so that the oil at the bottom of the piston 8 flows out through the orifice 12, resulting in extremely large damping. force is generated. In other words, the spring 15 is compressed to the maximum limit and has a large elasticity, but in this case, a large damping force is generated, so that the outer cylinder 2 is prevented from rising rapidly. Next, when the outer cylinder 2 and the inner cylinder 4 enter the stroke of descending simultaneously, the check valve 9 closes and the oil at the top of the piston 7 flows into the orifice 1.
1, and in this case the damping force is somewhat reduced.
In other words, when the spring 15 stretches and its elasticity decreases,
Since the damping force also decreases accordingly, the shock absorber extends at an appropriate speed. As described above, the hydraulic shock absorber of the present invention can obtain appropriate damping force retention properties depending on the strokes in the compression and extension strokes.

Therefore, it is possible to effectively alleviate a small impact when the vehicle body runs over a pebble or the like on the road surface, and at the same time, it is also possible to extremely effectively alleviate an impact caused by a large stroke. In addition, since the length of competition between the inner cylinder 4 and the outer cylinder 1 can be made sufficiently large, the friction at the beginning of the compression stroke of the shock absorber can be reduced, and the impact of particularly small strokes can be effectively absorbed. Moreover, the spring can be completely immersed in oil to prevent its wear and noise generation, which is an excellent effect.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view of an embodiment of the present invention, and FIGS. 2 and 3 are longitudinal sectional views showing the state of each stroke in the buffer shown in FIG. 1, respectively. In the figure, 1 and 2 are outer cylinders, 4 is inner cylinders, 5 and 6 are pipes, 7 and 8 are pistons, 9 and 10 are check valves, 11 and 1
2 is an orifice, 15 and 16 are springs, and 21 is oil.
Figure 1 Figure 2 Figure 3

Claims (1)

[Claims] 1. Two outer cylinders each having a pipe installed coaxially on the bottom and a piston formed at the tip of the pipe are arranged so that their open ends face each other, and both ends are connected to the two outer cylinders. The piston is slidably fitted inside an inner cylinder that is slidably fitted to the inner cylinder, check valves are provided at both ends of the inner cylinder, and an orifice is formed at a position near the tip of the pipe. The two outer cylinders and the inner cylinder are filled with oil, and a spring that presses the two outer cylinders in a direction separating them from each other and a spring that presses the inner cylinder in the direction of one of the outer cylinders are provided. A hydraulic shock absorber characterized by the provision of a hydraulic shock absorber.