JP2570015Y2 - Oil seal - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an oil seal used for, for example, an automobile shock absorber.

[0002]

2. Description of the Related Art FIG. 4 shows a configuration example of a conventional oil seal 100. The oil seal 100 has a metal ring 101 and a seal body 102 made of a rubber-like elastic body. The oil seal 100 is the outer cylinder 104 of the shock absorber 103
Are fitted and fixed to the inner periphery of On the inner periphery of the outer cylinder 104, one member having the shaft hole 105, that is, the guide 1 is provided.
06 is attached. A piston rod 107 as the other member is inserted into the shaft hole 105 so as to be capable of relative movement, that is, reciprocating movement.

A seal lip 108 and a dust lip 109 are provided on the inner peripheral side of the seal body 102 so as to contact the piston rod 107. An annular pressure adjusting lip 111 is provided on the seal body 102 at a position facing the end face 110 of the guide 106.
A first chamber 112 on the seal lip 108 side between the first chamber 112 and the guide 106, and a second chamber 1 adjacent to the outer peripheral side of the first chamber 112.
13 in the radial direction. This pressure adjusting lip 1
The tip of 11 is inclined toward the second chamber 113.

[0004] An inner cylinder 114 is assembled to the guide 106 to form an oil chamber 115 and an air chamber 116. The inner cylinder 114 is provided with an orifice 116a, while the piston 108 at the tip of the piston rod 107 is also provided with an orifice (not shown).

A passage 117 is provided on the end face of the metal ring 101 along the radial direction, and a drain 118 is provided on the outer peripheral face of the guide 106. Therefore, the second chamber 113
Communicates with the air chamber 116 through the passage 117 and the drain 118.

The shock absorber 103 having the above configuration is
The impact when the piston rod 107 reciprocates in the direction of the arrow is
The oil below the piston 108 is absorbed by the fluid resistance when passing through the orifice 116a and entering the air chamber 116. On the other hand, when the piston 107 rises, the oil in the oil chamber 115 enters the first chamber 112 through the shaft hole 105, but is sealed by the seal lip 108 and does not leak to the outside 119 of the shock absorber 103. .

[0007] When the piston 107 rises, the pressure in the first chamber 112 rises, and the pressure rise causes the pressure adjusting lip 111 to open to the outer peripheral side to form a gap with the end face 110. As a result, the oil in the first chamber 112 escapes into the second chamber 113 through the gap, and enters the air chamber 116 via the passage 117 and the drain 118.

As described above, since the pressure adjusting lip 111 functions as a pressure adjusting valve, the pressure in the first chamber 112 is prevented from rising, and the sealing property of the seal lip 108 is ensured.

[0009]

However, in the conventional oil seal 100, when the pressure in the second chamber 113 is abnormally high, for example, the piston rod 107 is lowered and the pressure in the air chamber 116 is increased. The pressure is drain 118,
When the pressure is transmitted into the second chamber 113 via the passage 117, the pressure adjusting lip 111 may be inverted toward the first chamber 112 as indicated by a two-dot chain line.

As a result, the pressure adjusting function of the first chamber 113 by the pressure adjusting lip 111 is impaired, and the first chamber 11
There is a possibility that the pressure in 3 increases and oil leaks to the outside 119 through the sealing surface of the sealing lip 108.

Therefore, it is conceivable to increase the rigidity by setting the thickness of the pressure adjusting lip 111 to be relatively large, but the valve opening pressure of the pressure adjusting lip 111 increases. It is also conceivable that the inclination angle of the pressure adjusting lip 111 is set to be large so that the pressure adjusting lip 111 approaches the horizontal in the drawing. However, in this case, when the oil seal 100 is molded, the pressure adjusting lip 111 is easily hooked on the mold when the mold is released from the mold, and there is a problem that the releasability is deteriorated.

This invention is intended to solve the above-mentioned problem, and has good releasability from a mold, maintains the operability of the pressure adjusting lip in the opening direction, and maintains the pressure adjusting lip when the pressure of the second chamber rises. It is an object of the present invention to provide an oil seal that can prevent the oil seal from being reversed to the first chamber side.

[0013]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides an annular seal body fixed to one of two members arranged so as to be movable relative to each other. A seal lip is formed in contact with the other member, and at a position of the seal body facing the end face of the one member, the seal lip side is provided between the seal body and one member in contact with the end face. In the oil seal in which a first chamber and a second chamber adjacent to the first chamber are provided with an annular pressure adjusting lip which is radially partitioned, and a tip side of the pressure adjusting lip is inclined toward the second chamber, Reinforcing means for preventing reversal of the pressure adjusting lip is provided on the second chamber side of the pressure adjusting lip, and the reinforcing means is provided on the pressure adjusting lip circumferentially.
A rigid part is formed along the direction,
As a result of the rise, the pressure adjustment
The low rigidity portion of the tip is deformed to be in an open state .

[0014]

According to the operation of the present invention based on the above configuration, the seal lip seals the fluid in the first chamber. Then, when the fluid pressure in the first chamber rises, the pressure adjusting lip is opened and a gap is formed between the first pressure adjusting lip and one of the members. Then, the fluid in the first chamber is released to the second chamber through the gap, and the pressure in the first chamber decreases.

Further, since the pressure adjusting lip is reinforced by the reinforcing means, even if the pressure in the second chamber increases, it does not reverse to the first chamber side.

Here, since the reinforcing means is partially provided, the pressure adjusting lip is formed with a portion having high rigidity and a portion having low rigidity along the circumferential direction, and is opened by deforming the low rigidity portion. State. Therefore, the pressure of the opening operation does not fluctuate. Further, the pressure adjusting lip can maintain a predetermined angle with respect to the direction of release from the mold during molding.

[0017]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 and 2 show a first embodiment. The oil seal 1 has a metal ring 2 and a seal body 3 made of a rubber-like elastic body baked on the metal ring 2, and the outer periphery thereof is fitted and fixed to the inner periphery of an outer cylinder 5 of a shock absorber 4. . One member having a shaft hole 6, that is, a guide 7, is attached to the inner periphery of the outer cylinder 5, and its end surface is in contact with the end surface of the metal ring 2.

An inner cylinder 50 is attached to the annular step 7a provided on the guide 7 on the opposite side of the oil seal 1. An oil chamber 51 is formed in the inner cylinder 50.
An air chamber 52 is formed between the outer cylinder 5 and the outer cylinder 5. Also,
While the inner cylinder 50 is provided with an orifice 53 connecting the oil chamber 51 and the air chamber 52, relative movement into the shaft hole 6, that is,
An orifice (not shown) is formed in the eccentric position of the piston 54 at the tip end of the piston rod 8 inserted reciprocally so as to penetrate in the axial direction.

A piston rod 8 is provided on the inner peripheral side of the seal body 3.
A seal lip 9 and a dust lip 10 are provided to be in contact with. A spring 16 is mounted on the seal lip 9. An annular pressure adjusting lip 12 is provided on the seal body 3 at a position facing the end face 11 of the guide 6,
The front end of the pressure adjusting lip 12 contacts the end face 11 and is located between the pressure adjusting lip 12 and the guide 7 of the seal body 3 on the seal lip 9 side, that is,
It is radially divided into an annular first chamber 13 on the inner peripheral side and a second chamber 14 adjacent to the outer peripheral side of the first chamber 13.

A passage 55 is provided in the metal ring 2 on the guide 7 side end surface along the radial direction, and a drain 56 is provided on the outer peripheral surface of the guide 7. Therefore, the second chamber 14 communicates with the air chamber 52 via the passage 55 and the drain 56. As shown in FIG. 2A, the passages 55 are equally arranged at a plurality of locations at predetermined intervals.

The tip end of the pressure adjusting lip 12 is inclined toward the second chamber 14, and its base, that is,
At a position on the metal ring 2 side facing the second chamber 14, a rib 15 is provided as a reinforcing means for preventing the pressure adjusting lip 12 from turning over to the first chamber 13 side. This rib 1
5 is partially formed on the metal ring 2 as shown in FIG.
That is, a plurality of radial members are provided corresponding to the passages 55. Note that the rib 15 may be formed regardless of the passage 55. Further, the cross-sectional shape of the rib 15 is not limited to the rectangular shape in FIG. 4 and may be a triangle, a semicircle, or the like.

Next, the operation of the above embodiment will be described. In the shock absorber 4, the piston rod 8 reciprocates in the direction of arrow A, and when the piston 54 descends, a part of the oil below the piston 54 enters the piston 54 through an orifice (not shown) of the piston 54. And others pass through the orifice 53 and enter the air chamber 52. As described above, the shock applied to the piston rod 8 is absorbed by the fluid resistance when the oil passes through the orifice.

On the other hand, when the piston rod 8 rises, the oil in the air chamber 52 returns to the oil chamber 51 through the orifice 53, while the oil above the piston 54 in the oil chamber 51 passes through the shaft hole 6. Although it enters into the one chamber 13, the space between the piston rod 8 and the piston rod 8 is sealed by the seal lip 9 and does not leak to the outside 57 of the shock absorber 4.

When the piston rod 8 is raised, the first chamber 13
When the internal pressure rises, the pressure rise causes the pressure adjusting lip 12 to open to the outer peripheral side as shown in FIG. 1B, and a gap L is formed between the pressure adjusting lip 12 and the end face 11 of the guide 7. Then, the oil in the first chamber 13 is released into the second chamber 12 through the gap L, and enters the air chamber 52 through the passage 55 and the drain 56, so that the pressure in the first chamber 13 is reduced. Be lowered. As a result, the pressure adjusting lip 12 returns to its original position as shown in FIG.

As described above, the pressure adjusting lip 12 functions as a pressure adjusting valve, thereby preventing an increase in the pressure in the first chamber 13 and ensuring the sealing property of the seal lip 9. If the pressure in the second chamber 14 is abnormally increased during the above operation, for example, the piston rod 8 is lowered to increase the pressure of the oil in the air chamber 52, and the pressure is increased via the drain 56 and the passage 55. Even if it is transmitted into the first chamber 14, since the pressure adjusting lip 12 is reinforced by the rib 15, the first chamber 1
There is no inversion to the third side.

Accordingly, the pressure in the first chamber 13 can be prevented from rising, and the sealing property of the seal lip 9 can be stably maintained. Further, since the ribs 15 are partially evenly distributed, the pressure adjusting lip 12 has a high rigidity portion and a low rigidity portion along the circumferential direction, and the low rigidity portion is deformed to open. Becomes Therefore, there is no fluctuation in the valve opening pressure. Therefore, FIG.
The gap L is formed smoothly without affecting the opening operation shown in FIG.

In the illustrated embodiment, the oil passage 55
Since the ribs 15 are provided corresponding to the above, the reinforcing function works effectively. Further, the pressure adjusting lip 12 can maintain a predetermined angle with respect to the direction of release from the mold during molding. Therefore, when the oil seal 1 is released from the mold after molding,
The pressure adjusting lip 12 does not catch on the mold, and the mold releasing property is good.

FIG. 3 shows a second embodiment. In this embodiment, a plurality of ribs 15 are provided radially only on the tip side of the pressure adjusting lip 12. (C) and (D) show FIG.
It is a top view sectional view in the CC line of (B).

The ribs 15 may be provided at eight positions at equal angular intervals as shown in FIG. 3C, or may be formed at nine positions or more as shown in FIG. On the inner peripheral side of the seal lip 9, an annular parallel projection 70 is provided. Other configurations are the same as those of the first embodiment, and the same operation and effect can be obtained.

Although the first and second embodiments are applied for reciprocating movement, they may be used between two members which rotate. Further, the oil seal may be fixed to the shaft, and the seal lip may be brought into contact with the housing.

[0031]

[Effect of the Invention] The present invention is constructed as described above, so that when the pressure in the second chamber increases, the pressure adjusting lip does not reverse to the first chamber side. Therefore, the pressure rise in the first chamber can be always prevented, and the sealing property of the seal lip can be stably maintained.

Since the reinforcing means is partially provided, the operating pressure in the opening direction of the pressure adjusting lip does not fluctuate. Further, the releasability from the mold after molding is good.

[Brief description of the drawings]

1A is a half sectional view of a first embodiment in which the present invention is applied to a shock absorber, and FIG. 1B is a partial half sectional view showing an open state of a pressure adjusting lip of an oil seal of FIG.

2A is a plan view of the oil seal of FIG. 1 as viewed from the pressure adjusting lip side, and FIG. 2B is a partial cross-sectional plan view taken along line BB of FIG. 2A.

3A is a half sectional view showing an oil seal according to a second embodiment, FIG. 3B is an enlarged sectional view of a main part of FIG. 3A, and FIGS.
FIG. 4 is a plan cross-sectional view taken along line CC of FIG.

FIG. 4 is a half sectional view showing a conventional oil seal for a shock absorber.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 oil seal 2 metal ring 3 seal body 4 shock absorber 5 outer cylinder 6 shaft hole 7 guide 8 piston rod 9 seal lip 10 dust lip 11 end face 12 pressure adjustment lip 13 first chamber 14 second chamber 15 rib 50 inner cylinder 51 oil Chamber 52 Air chamber 53 Orifice 54 Piston 55 Passage 56 Drain 57 External

Claims (1)

(57) [Scope of request for utility model registration] 1. An annular seal body fixed to one of two members arranged so as to be relatively movable,
A seal lip is formed on the seal body so as to be in contact with the other member, and a seal lip is provided between the seal body and the one member in contact with the end surface at a position facing the end surface of the one member. The first chamber on the seal lip side and the second chamber adjacent to the first chamber are provided with an annular pressure adjustment lip radially partitioned, and the tip side of the pressure adjustment lip is inclined toward the second chamber. In the oil seal, reinforcing means for preventing the reversal of the pressure adjusting lip is provided on the second chamber side of the pressure adjusting lip, and the reinforcing means is provided in a partly equal manner.
Form a rigid portion along the circumferential direction on the force adjustment lip
And the reinforcing means is provided by the pressure increase in the first chamber
The low rigidity part of the pressure adjustment lip is deformed and opened.
An oil seal characterized by being in a state .