JPS5923886Y2 - Shock absorber with built-in damping force adjustment mechanism - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a shock absorber having a built-in mechanism for adjusting the damping force on the rebound side.

When a damping force adjustment mechanism is built into a shock absorber, the structure shown in FIG. 1 is the first consideration.

In the shock absorber shown in FIG. 1, a leaf valve 7 is provided on the piston 6, and the leaf valve generates a damping force on the compression side.

Further, a bypass passage 2 is formed in the piston rod 1, and a rotation adjustment member 3 is fitted into the upper open end portion of the bypass passage 2.

This rotation adjustment member 3 is formed with a plurality of orifices 4 having different diameters.

Now, if the shock absorber is maintained at its maximum extension and the rotation adjustment member 3 is brought into pressure contact with the cushion member 8 to rotate the piston rod 1, the piston rod 1 and the rotation adjustment member 3 will rotate relative to each other. The upper opening end of the bypass passage 2 is opposed to an arbitrary orifice 4 of the rotation adjustment member 3 to adjust the damping force on the expansion side.

In such a shock absorber, there is a problem that when the rebound side damping force is adjusted, the compression side damping force also changes.

In other words, since the bypass passage 2 always maintains a communicating state, the above-mentioned orifice 4 for exerting the rebound damping force
However, it may also affect the compression damping force.

Further, during the compression stroke, the high pressure below the piston 6 acts on the rotation adjustment member 3 via the bypass passage 2, so a choke-like gap 5 is formed between the piston rod 3 and the rotation adjustment member 3. .

Oil leaks from this gap 5, but the viscosity of the oil changes depending on changes in oil temperature.

As a result, the damping resistance varies and the problem arises that the damping force during the compression stroke is not stable.

In order to solve the above-mentioned problems, this invention provides a check valve that opens only during the extension stroke in the bypass passage of the piston rod. The purpose is to provide a buffer that does not cause

This will be explained below for each illustrated implementation.

In the first embodiment shown in FIGS. 2 and 3, a piston 12 is slidably installed inside a cylinder 11, and the other end of a piston rod 13, which has one end fixed to the piston 12, protrudes outward from the cylinder 11. I'm letting you do it.

The piston 12 has an oil passage hole 14, and a leaf valve 15 is disposed above the oil passage hole 14 to obtain a damping force during the compression stroke.

A positioning plate 16 is fixed above the leaf valve 15, and a rotation adjustment member 17 is placed on the positioning plate 16.
is rotatably engaged with the piston rod 13.

A plurality of orifices 18 having different diameters are formed in the rotation adjustment member 17, and a desired orifice 18 among these orifices 18 is formed in the piston rod 13, and a bypass opening is formed above and below the piston 12. aisle 19
By matching the upper opening of the orifice, the orifice characteristics can be arbitrarily selected.

The rotation adjustment member 17 is positioned as follows.

That is, the shock absorber is extended to bring the rotation adjustment member 17 into pressure contact with the cushion material 20.

When the piston rod 13 is then rotated, since the rotation adjustment member 17 is prevented from rotating by the cushion material 20, the piston rod 13 and the rotation adjustment member 17 rotate relative to each other.

At this time, the position where the ball 21 provided in the rotation adjustment member 17 is press-fitted into the recess 23 of the positioning plate 16 by the action of the spring 22 becomes the coincident point of the orifice and the bypass passage.

A check valve 24, which is the most important element of this invention, is provided in the bypass passage 19.

This check valve 24 allows oil to flow only when the shock absorber is extended, and blocks oil flow when it is compressed, and its specific configuration is as follows.

That is, the check valve 24, which has a reverse circular cross section, is inserted into the enlarged diameter portion 25 formed at the lower end of the bypass passage 19 so as to be vertically movable above the ring 26.

The check valve 24 is formed with a large number of small holes 27 that are raised by the upper surface of the enlarged diameter portion 25 when the check valve 24 is pressed upward.

Therefore, during the extension stroke of the shock absorber, check valve 2
4 descends downward, so the bypass passage 19 communicates through the small hole 27.

Further, during the compression stroke, the check valve comes into close contact with the upper surface of the enlarged diameter portion 25 and its small hole 27 is closed, so that the flow of oil in the bypass passage 19 is blocked.

Note that the check valve in this invention may be of any type, such as a ball valve or a pivot valve, as long as it can perform the above function.

Since the check valve 24 is provided to prevent the flow of oil in the bypass passage during the compression stroke, only the leaf valve 15 functions during the compression stroke.

In the second embodiment shown in FIGS. 4 and 5, a piston 32 is slidably installed inside a cylinder 31, and the other end of a piston rod 33, which has one end fixed to the piston 32, protrudes outward from the cylinder 31. I'm letting you do it.

An oil passage hole 34 is formed in the piston 32, and a leaf valve 35 is provided above the oil passage hole 34, but the function of this leaf valve 35 is completely the same as in the first embodiment.

In addition, the reference numeral 36 in the figure is a cushion material, and the reference numeral 37 is a member.

The inside of the piston rod 33 is hollow, and an operating rod 38 is rotatably inserted into the hollow portion, and a rotation adjustment member 40 is fixed to the tip of the operating rod 38 facing the bypass passage 39.

This rotation adjustment member 40 is formed with a plurality of orifices 41 having different diameters, and by rotating the operating rod 38 and aligning one of the orifices 41 with the communication hole 42 formed in the piston rod 33. , the orifice characteristics can be selected arbitrarily.

Note that the communication hole 42 constitutes a part of the bypass passage of this invention, and therefore, in this embodiment as well, the bypass passage opens above and below the piston.

The bypass passage 39 is provided with a check valve 43 similar to that of the first embodiment.

That is, a collar 44 is fixedly engaged with the lower end of the bypass passage 39, and the check valve 43 is slidably provided between the collar 44 and a ring 45 attached below the collar 44.

A small hole 46 similar to that of the first embodiment is formed in this check valve 43.

Note that, as in the first embodiment, the check valve may be of any type.

As is clear from the above explanation, according to this invention, only the leaf valve functions during the compression stroke of the shock absorber, so even if there is a gap between the rotation adjustment member and the piston rod, the compression stroke The damping force during the extension stroke can be adjusted independently without adversely affecting the damping force characteristics of the cylinder.

[Brief explanation of the drawing]

Figure 1 is a cross-sectional view of the main part of a shock absorber with a built-in damping force adjustment mechanism, Figures 2 and 3 show the first embodiment of this invention, Figure 2 is a cross-sectional view of the main part, and Figure 3 is a cross-sectional view of the main part. The figure is an enlarged sectional view of the check valve, and FIGS. 4 and 5 are sectional views of essential parts and enlarged sectional views of the check valve, respectively, showing the second embodiment. 12, 32... Piston, 15.35...
...Leaf valve, 17, 40...Rotation adjustment member, 18.41, curve, orifice, 19, 39...
...Bijas passage, 24.43...Tune check valve.

Claims (1)

[Scope of utility model registration request] A leaf valve is provided on the piston, and a rotation adjustment member is provided, which forms a bypass passage that opens above and below the piston, and has a plurality of types of orifices that provide throttling resistance to the flow passing through the bypass passage. The shock absorber has a built-in damping force adjustment mechanism on the rebound side, which is equipped with a check valve that closes the passage during the compression stroke.