JPH0617704B2 - Shock absorber - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a shock absorber, and more particularly, to an improvement of a shock absorber that allows oil lock during extension.

[Prior Art] Various proposals have been made in the past as a shock absorber capable of allowing oil lock at the time of distraction. For example, in the shock absorber as shown in FIG. It is assumed that the bearing member 2 disposed inside the extension side end (upper end in the drawing) has a recess 2a formed toward the piston portion 3 in the cylinder 1, while the piston portion 3 is provided at the lower end. In the piston rod 4 whose upper end side penetrates the shaft core portion of the bearing member 2, a stopper 5 which is a fitting member fitted in the recess 2a is provided near the lower end of the piston rod 4, that is, above the piston portion 3. It is supposed to be installed.

An oil passage 5a is formed on the inner peripheral side of the stopper 5, and the opening on the lower end side of the oil passage 5a is closed.
An annular valve 6 is arranged at the lower end of the stopper 5. The valve 6 is supported by the valve stopper 7 from below. The valve stopper 7 is formed with a port 7a facing the lower surface of the valve 6, and the valve stopper 7 is fixed to a predetermined position by a stop O-ring 8 with respect to the piston rod 4. Has been formed.

Therefore, in the above-mentioned conventional proposal, when the piston portion 3 further rises in the cylinder 1 from the state shown in the drawing, the stopper 5 is fitted into the recess 2a of the bearing member 2, and An oil lock chamber A'is formed in the recess 2a, so that a so-called oil lock state in which the working oil is confined in the oil lock chamber A'can be brought about.
When the stopper 5 is fitted into the recess 2a, the inside of the recess 2a is not suddenly brought into a high-pressure oil lock state, but the working oil in the recess 2a passes through the oil passage 5a of the stopper 5 and the valve. Considering that the inside of the recess 2a is gradually increased in pressure by letting it open to the outside in the expansion side chamber A by opening 6, the desired oil lock state at the so-called extension of the shock absorber can be obtained in a preferable state. There is.

[Problems to be solved by the invention]

However, in the above-mentioned conventional proposal, since the bearing member 2 is arranged in the cylinder 1 and the stopper 5 fitted in the recess 2a of the bearing member 2 is arranged in the piston rod 4, In the formation of the bearing member 2 and the stopper 5, extremely precise precision control is required for so-called centering around the shaft center of the piston rod 4, and when the control is not sufficient, a desired oil lock state is brought about. There is an inconvenience.

Therefore, in view of the above-mentioned circumstances, an object of the present invention is to newly provide a shock absorber capable of obtaining a desired oil lock effect without requiring a precise precision control.

[Means for solving problems]

In order to solve the above-mentioned problems, the structure of the present invention is such that a sleeve is arranged on the inner circumference of the extension side end of the cylinder, and the inner circumference of the other end side of the sleeve is fixed to the outer circumference of the piston rod. The stopper is capable of sliding contact with the outer circumference of the valve that is held so that it can move in the axial direction and the radial direction, and when the piston rod is extended, the sliding contact between the outer circumference of the valve and the inner circumference of the sleeve is allowed. It is characterized in that a desired oil lock chamber can be formed inside the extension side end of the cylinder.

〔Example〕

 Hereinafter, the present invention will be described based on the illustrated embodiments.

As shown in FIG. 1, a shock absorber according to a preferred embodiment of the present invention has a piston portion 11 inside a cylinder 10.
And a piston rod 12 having the piston portion 11 at the lower end thereof penetrates the shaft core portion of a bearing member 13 disposed at the upper end of the cylinder 10 and has its upper end extended to the outside. Is formed.

The inside of the cylinder 10 is partitioned by the piston part 11 into the expansion side chamber A and the compression side chamber B, and the both side chambers A and B are allowed to communicate with each other via the piston part 11, so that the working oil is the piston. It is formed so that a desired damping force is generated when passing through the portion 11.

In this embodiment, the outer cylinder 14 is arranged outside the cylinder 10 to form a so-called multi-cylinder type shock absorber.
A reservoir chamber C is provided between and. Although not shown, the reservoir chamber C and the pressure side chamber B are formed so as to communicate with each other via a base valve portion provided at the lower bottom portion of the cylinder 10.

The upper end, which is the extension side end of the cylinder 10, has a bearing member 13
The bearing member 13 has an oil seal 15 and a check seal 16 housed therein. Further, the bearing member 13 is formed with a drain port 13a which allows the inner peripheral side and the outer peripheral side to communicate with each other, and the outer peripheral side opening of the drain port 13a has a gas above the reservoir chamber C. It opens to chamber D. Further, a bush 17 is arranged on the inner peripheral side of the bearing member 13 so that the piston rod 12 can slide.

The bearing member 13 is formed to be fixed at a predetermined position by bending the upper end of the outer cylinder 14 inward.

Next, the oil lock mechanism according to the present invention is formed as follows.

That is, as shown in FIG. 2, the oil lock mechanism according to the present invention includes the sleeve 18 disposed on the inner periphery of the upper end, which is the extension side end of the cylinder 10, and the piston rod 12.
An appropriate gap δ is formed on the outer circumference of the stopper 19 fixed on the outer circumference of
And a valve 20 formed so that the piston rod 12 rises in the cylinder 10 at the end of the extension side stroke as shown in FIG. The outer circumference of the valve 20 is slidably contacted with the inner circumference of the sleeve 18 at the time of the extension, thereby forming a desired oil lock chamber A'on the inner circumference side of the sleeve 18.

The sleeve 18 is the cylinder 1 in this embodiment.
The upper end, which is one end of the bearing member 13 disposed at the upper end of 0, is formed adjacent to the bearing member 13. However, instead of this, the one end is separated from the bearing member 13 and is formed in the vicinity thereof. It may be done. In addition, the sleeve 1
The outer periphery of 8 is supposed to be in close contact with the inner periphery of the cylinder 10, but it is not necessary to be in close contact, and so-called backlash may be maintained.

In the present embodiment, the stopper 19 is arranged by the C ring 21 fitted on the outer periphery of the piston rod 12 so as not to descend further to the piston rod 12, and the stopper 19 is The lower end of the stopper 19 is bent toward the piston rod 12 so that the stopper 19 does not rise above the piston rod 12. The stopper 19 is a C ring 21.
However, instead of this, the pin may be fixed by using a pin, for example.

An orifice 19a is formed on the stopper 19 along the axial direction. As shown in FIG. 3, the outer periphery of the valve 20 is slidably contacted with the inner periphery of the sleeve 18, and the oil lock chamber A It is taken into consideration that the hydraulic oil in the oil lock chamber A ′ will flow into the extension side chamber A via the orifice 19a when ′ ′ is formed. That is, the inside of the oil lock chamber A'is taken into consideration so as not to be suddenly increased in pressure.

Although the outer circumference of the valve 20 is in sliding contact with the inner circumference of the sleeve 18, it is needless to say that the outer circumference of the valve 20 is not in a close contact state in order to secure so-called slidability.

In the present embodiment, as shown in FIG. 4, the valve 20 is formed in a cap shape as a whole, and has a wide body portion 20a formed in an annular shape, the body portion 20a, An annular locking portion 20b that is connected to one side edge of the body portion 20a, that is, the side edge on the oil lock chamber A'side, and the other side edge of the body portion 20a, that is, the side edge on the extension side chamber A side. And a locking piece 20c continuously arranged in the form of a tongue, the locking portion 20b and the locking piece 20c.
Between the stopper 19 and the stopper 19 is formed so that the stopper 19 can move in the axial direction thereof, that is, the valve 20 can move relative to the stopper 19 (FIGS. 2 and 5). See figure).

Further, in the present embodiment, it is assumed that the valve 20 is urged by the spring 22 so that the valve 20 does not become idle with respect to the stopper 19 more than necessary. The inner circumference is the stopper 19
It is assumed that the outer peripheral side is disposed at the lower end of the above so as to come into contact with the locking pieces 20c, respectively. Therefore, the valve 20 closes the gap δ formed between the outer periphery of the stopper 19 and the inner periphery of the valve 20 with the engaging portion 20b by the urging force of the spring 22, and the gap δ is filled with hydraulic oil. Are formed so as to prevent the passage of the.

Since the gap δ is formed between the stopper 19 and the valve 20, the valve 20 is of course movable in the so-called radial direction with respect to the stopper 19.

In the oil lock mechanism of the present invention formed as described above, the oil lock effect can be exhibited and released as follows.

That is, first, as shown in FIG. 3, the oil lock effect is exerted by the piston rod 12 moving up in the cylinder 10 and, at the time of extension, the valve 20 is fitted into the sleeve 18, and The hydraulic oil in the oil lock chamber A'formed inside 18 is allowed to flow into the extension side chamber A only through the orifice 19a of the stopper 19 (see arrow a in FIG. 3).

At this time, of course, the gap δ between the stopper 19 and the valve 20 is closed by the locking portion 20b.

Therefore, the pressure in the oil lock chamber A'is gradually increased, the piston rod 12 rises in the cylinder 10, that is, the so-called piston speed is reduced, and the desired oil lock effect is obtained.

Next, when the piston rod 12 enters the pressure side stroke in which the piston rod 12 descends in the cylinder 10 by reversing from the oil lock time,
Negative pressure will be generated in the oil lock chamber A ',
Since the orifice 19a is formed on the stopper 19,
The hydraulic oil on the extension side chamber A side flows into the oil lock chamber A'side via the orifice 19a (see arrow b in FIG. 5).

The negative pressure generated in the oil lock chamber A'is released to allow the stopper 19 to descend to overcome the spring 22. Then, due to the lowering of the stopper 19, the working oil in the extension side chamber A flows into the oil lock chamber A ′ even through the gap δ formed between the outer periphery of the stopper 19 and the inner periphery of the valve 20. (Refer to arrow b'in FIG. 5), the negative pressure generation in the oil lock chamber A'is released more smoothly.

The stopper piece 20 of the valve 20 is lowered by lowering the stopper 19.
The stopper 19 is brought into contact with c, and the valve 20 is connected to the stopper 1.
9 descends in the sleeve 18 together with 9, and comes out from the lower end of the sleeve 18.

As described above, the cylinder 10 of the piston rod 12
At the time of inward extension, the valve 20 is fitted into the sleeve 18 to form a desired oil lock chamber A ′.
Since it is arranged in a floating state, that is, the valve 2
Since the stopper 19 that locks 0 is formed so as to have an appropriate gap δ with the valve 20, the sleeve 1
If only the accuracy control in the main body portion 20a of the valve 20 for 8 is sufficient, the stopper 19 fixed to the piston rod 12 does not need the accuracy control more than necessary.

FIG. 6 shows another embodiment of the valve 20 described above, in which the valve 23 is formed in a slightly long tubular main body 23a and one side edge of the main body 23a. A locking portion 23b, and a locking piece 23c that is formed by cutting an approximately central portion of the main body portion 23a and bending it inward, and
The main body portion 23a has a tapered portion 23a '.
The taper portion 23a 'is formed so as to descend and incline from the extension side chamber A side edge (right edge in the figure) to the oil lock chamber A'side edge (left edge in the figure).
The a'is replaced with the orifice 19a of the stopper 19 described above.

The taper portion 23a 'is formed on the outer peripheral side of the main body portion 23a, but instead of this, the main body portion 23a itself is preliminarily formed in the shape of a truncated cone, and the taper portion 23a' is formed. It may be formed on the inner peripheral side. Also in the present embodiment, it goes without saying that a gap δ is formed between the valve 23 and the stopper 19.

FIG. 7 shows still another embodiment of the valve 20, which is constructed as a modification of the valve 23 shown in FIG.

That is, the valve 24 has a main body portion 24a, a locking portion 24b, and a locking piece 24c.
It is assumed that an incision 24a 'is formed instead of a'. Even in this embodiment, the stopper 19 (see FIG. 2) has a gap δ with respect to the valve 24.
Needless to say, it is so-called movable.

〔The invention's effect〕

As described above, according to the present invention, since an appropriate gap is formed between the stopper fixed to the piston rod and the valve interposed therein, extremely precise accuracy control is required. It is an advantage to obtain a shock absorber capable of exhibiting a desired oil-rolling-side oil lock effect.

Further, according to the present invention, even when the expansion side oil lock is reversed to the compression side stroke, the negative pressure is released in a preferable state, and the smooth start of the compression side stroke of the piston rod is enabled.

[Brief description of drawings]

FIG. 1 is a partially cutaway front view showing a shock absorber according to a preferred embodiment of the present invention, FIG. 2 is a partial sectional view showing an enlarged main part, and FIGS. 3 and 5 show the main part. FIG. 4 is a view showing an operating state similarly to FIG. 2, FIG. 4 is a perspective view showing a valve,
FIGS. 6 and 7 are views showing another embodiment of the valve in the same manner as in FIG. 4, and FIG. 8 is a view showing the main part of the conventional shock absorber in the same manner as in FIG. 10 ... Cylinder, 11 ... Piston part, 12 ... Piston rod, 13 ... Bearing part, 14 ... Outer cylinder, 15 ... Oil seal, 16 ... Check seal, 18 ... Sleeve, 19 ... Stopper, 19a ... Orifice, 20, 23, 24 … Valve, 20a, 23
a, 24a ... main body, 20b, 23b, 24b ... locking portion, 20c, 23c, 24c ...
Locking piece, 23a '... Tapered portion, 24a' ... Incision portion, A ... Extension side chamber, A '... Oil lock chamber, B ... Pressure side chamber, C ... Reservoir chamber, D ... Gas chamber, δ ... Gap.

Claims (4)

[Claims] 1. A shock absorber capable of forming an oil lock chamber inside the extension side end of a cylinder, wherein a sleeve is disposed on the inner side of the extension side end of the cylinder, and the inner periphery of the other end side of the sleeve. The outer circumference of the valve, which is held by the stopper fixed to the outer circumference of the piston rod so as to be movable in the axial direction and the radial direction, is slidable. A shock absorber characterized in that a desired oil lock chamber can be formed inside the extension side end of the cylinder by allowing sliding contact with the inner circumference of the sleeve. 2. The shock absorber according to claim 1, wherein one end of the sleeve is formed so as to be adjacent to or adjacent to a bearing member disposed inside the extension side end of the cylinder. 3. A spring is interposed between the stopper and the valve, and the spring prevents the hydraulic oil from passing through a gap formed between the stopper outer periphery and the valve inner periphery. The shock absorber according to claim 1, wherein a valve is energized on the shock absorber. 4. The invention according to claim 1, which is formed so as to prevent hydraulic oil from passing through a gap formed between the outer circumference of the stopper and the inner circumference of the valve when the piston rod is fully extended.
The shock absorber described in the item.