JPH08178078A - Packing - Google Patents

Abstract

PURPOSE: To resolve the problem that a packing main body is dragged by another member and protruded by providing a recess on one end face in the axial direction of a backup ring in a packing assembled with the backup ring at the step section of the packing main body. CONSTITUTION: This packing applied to the rod section of a hydraulic cylinder or the like is provided with a lip section 2 closely stuck to another member 52 on one end side in the axial direction, a packing main body 1 made of a rubbery elastic material and having a step section 3 on the peripheral face on the other end side in the axial direction, a backup ring 4 made of a resin or a metal and assembled on the step section 3, a recess 7 formed on one end face 4b in the axial direction of the backup ring 4 and communicated with a space 54 surrounded by the packing main body 1, the backup ring 4, and the other member 52, and a through hole 8 penetrating the backup ring 4 in the axial direction and opened on the bottom face 7a of the recess 7.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a packing which is a kind of sealing device.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG. 2 and FIG. 3, an annular mounting groove 53 provided in one member 51 of two members 51, 52 that move relative to each other, such as a rod portion of a hydraulic cylinder. A reciprocating packing that is mounted and seals between the two members 51, 52. The one end in the axial direction (upper side in the drawing) is provided with the lip portion 2 in close contact with the other member 52 and the other end in the axial direction. A packing body 1 made of a rubber-like elastic material having a step portion 3 on its peripheral surface (upper and lower sides in the figure), and a resin or metal backup ring 4 incorporated in the step portion
Those with and are known.

However, in this conventional packing, the sealing fluid may slightly leak from the sliding portion between the lip portion 2 and the other member 52, which causes the packing body 1 and the backup ring. The seal fluid is accumulated in the space 54 surrounded by the fourth member 52 and the other member 52, the pressure in the space 54 rises, the close contact force of the lip portion 2 with the other member 52 is reduced, and finally the seal becomes impossible. However, there is a problem that blow-through leakage occurs.

In order to prevent the occurrence of blow-through leakage,
Conventionally, the following ideas have been made. As shown in FIG. 4, a groove 5 is provided on the peripheral surface 4a of the backup ring 4 on the side of the other member 52, and the groove 5 is used as a pressure relief channel from the space 54 to the low pressure side space 55 (see FIG. 3). Relieve pressure. As shown in FIG. 5, a U-shaped groove 6 is provided on one end surface 4b in the axial direction of the backup ring 4, the peripheral surface 4c on the packing body 1 side and the other end surface 4d in the axial direction, and the groove 6 is used as a pressure relief channel. The pressure is released from the space 54 to the low pressure side space 55 (see FIG. 3).

However, when the groove 5 is provided on the peripheral surface 4a on the other member 52 side of the backup ring 4 as described above, the packing body 1 made of a rubber-like elastic material is provided when a high pressure acts on the packing. May be extruded from the groove 5 by being dragged by the other member 52, which may cause the packing body 1 to be damaged. Also, as shown in FIG.
b, the peripheral surface 4c on the packing body 1 side and the other axial end surface 4
When the U-shaped groove 6 is provided in d, when a high pressure is applied to the packing, the packing main body 1 made of a rubber-like elastic material is bent in a U-shape of the groove 6 as shown in FIG. There is a case where the portion is filled up and the pressure relief flow path is closed, and as a result, there is a risk that blow-through leakage may occur.

[0006]

SUMMARY OF THE INVENTION In view of the above points, the present invention provides a packing in which the packing body is prevented from protruding by being dragged by the other member and thus the packing body is not damaged. The purpose is to In addition, it is another object of the present invention to provide a packing in which the packing body does not block the pressure relief flow path provided in the backup ring, so that the leakage does not occur.

[0007]

In order to achieve the above object, the packing of the present invention is mounted in an annular mounting groove provided in one of two members that move relative to each other, and is attached to one end in the axial direction. A packing body having a lip portion in close contact with the other member and a step portion provided on the circumferential surface on the other end side in the axial direction,
In a packing including a backup ring incorporated in the step portion, one end surface in the axial direction of the backup ring is provided with a recess communicating with a space surrounded by the packing body, the backup ring, and the other member, A through hole penetrating the backup ring in the axial direction is provided so as to open in the bottom surface of the recess.

[0008]

In the packing of the present invention having the above structure, the space surrounded by the packing main body, the backup ring and the other member and the low-pressure side space communicate with each other through the recess and the through hole, and the recess and the through hole are connected to each other. The depressurizing flow path is set. The through hole does not face the other member like the groove described above, so that it is possible to prevent the packing main body from being pulled out by being dragged by the other member. Further, since the pressure relief flow channel including the recess and the through hole does not have a U-shaped bent portion unlike the groove described above, the packing main body fills this bended portion and blocks the pressure relief flow path. Can be prevented. The recess prevents the opening of the through hole from being blocked by the packing body, and ensures that the space and the through hole are in communication.

[0009]

Next, an embodiment of the present invention will be described with reference to the drawings.

As shown in FIG. 1, the packing according to this embodiment has the other member 52 on one axial side (upper side in the figure).
(See FIG. 3 or FIG. 6) A packing body 1 made of a rubber-like elastic material, which is provided with a lip portion 2 which is in close contact with the same, and a step portion 3 is provided on a peripheral surface on the other end side (upper and lower sides in the axial direction) in the axial direction; Resin or metal backup ring 4 built into the part 3
And the following configuration. That is, the packing main body 1, the backup ring 4, and the other member 5 are attached to the axially one end surface 4b of the backup ring 4.
A recess 7 communicating with a space 54 surrounded by 2 (see FIG. 3 or 6) is provided, and a through hole 8 axially penetrating the backup ring 4 is formed in the recess 7. It is provided so as to open to the bottom surface 7a.

In the packing having the above structure, the space 54 surrounded by the packing body 1, the backup ring 4 and the other member 52 and the low pressure side space 55 (see FIG. 3 or 6) have the recess 7 and the through hole 8. Communication through
A pressure relief channel is set through the recess 7 and the through hole 8. Therefore, first, the lip portion 2 and the other member 52
Even if the sealing fluid leaks from the sliding portion with the sealing fluid, the sealing fluid can escape to the low-pressure side space 55 through the pressure relief flow path, thereby preventing the sealing fluid from accumulating in the space 54. can do. Therefore, this space 5
Since the pressure of No. 4 does not increase and the close contact force of the lip portion 2 with the other member 52 does not decrease, it is possible to prevent the occurrence of blowout leakage due to the failure of sealing. .

In the packing having the above structure, the through hole 8 does not face the other member 52. Therefore, the packing body 1 made of rubber-like elastic material is
It is possible to prevent the packing body 1 from being pulled out by being pulled out, so that the packing body 1 can be prevented from being damaged. In the packing having the above structure,
The pressure relief flow path including the recess 7 and the through hole 8 does not have a U-shaped bent portion. Therefore, it is possible to prevent the packing main body 1 from filling the bent portion and blocking the pressure relief flow path, and as a result, it is possible to prevent blow-through leakage.

If necessary, a plurality of pressure-relieving flow paths, which are composed of the recesses 7 and the through holes 8, are arranged in the circumferential direction. Recess 7
1 extends from the inner peripheral edge to the outer peripheral edge of the one end face 4b in the axial direction, the opening of the through hole 8 is originally the packing main body 1
Since it is provided so as to prevent the space 54 and the through hole 8 from communicating with each other by surely communicating with each other, if this action can be ensured, the inner peripheral edge of the one axial end surface 4b is reached. You don't have to. Further, it may not reach the outer peripheral edge of the axial one end surface 4b, and may not reach both the inner peripheral edge and the outer peripheral edge of the axial one end surface 4b.

Further, when the other axial end surface 4d of the backup ring 4 abuts on the side wall of the mounting groove 53 (see FIG. 3 or 6) and the opening of the through hole 8 on this side is closed by this side wall, As shown in FIG. 1, a recess 9 is also provided in the other axial end surface 4d so that the through hole 8 is opened in the bottom surface 9a of the recess 9, whereby the recess 7 and the through hole 8 are formed.
And the pressure relief channel consisting of the recess 9 is set. This recess 9 is also provided so as to prevent the opening of the through hole 8 from being blocked by the side wall of the mounting groove 53 and ensure the communication between the through hole 8 and the low pressure side space 55. If it is possible to ensure the
It does not need to reach from the inner peripheral edge to the outer peripheral edge of d. That is, it may not reach the inner peripheral edge of the other axial end surface 4d, may not reach the outer peripheral edge of the other axial end surface 4d, and may reach both the inner peripheral edge and the outer peripheral edge of the other axial end surface 4d. You don't have to.

[0015]

The present invention has the following effects.

That is, in the packing of the present invention having the above-mentioned structure, the through hole forming the depressurizing flow path does not face the other member, so that the packing body can be dragged by the other member. It is possible to prevent the packing body from protruding, and thus to prevent the packing body from being damaged. Further, in the packing of the present invention, the pressure relief channel formed of the concave portion and the through hole does not have a U-shaped bent portion, and therefore the packing body fills the bent portion and blocks the pressure relief flow path. It is possible to prevent the occurrence of blow-through leakage as a result.

[Brief description of drawings]

FIG. 1 is a half sectional view of a packing according to an embodiment of the present invention.

FIG. 2 is a half cutaway view of a packing according to a conventional example.

FIG. 3 is a cross-sectional view of essential parts showing a mounted state of the packing.

FIG. 4 is a half sectional view of a packing according to another conventional example.

FIG. 5 is a half sectional view of a packing according to another conventional example.

FIG. 6 is a cross-sectional view of essential parts showing a mounted state of the packing.

[Explanation of symbols]

 1 Packing Body 2 Lip Part 3 Step Part 4 Backup Ring 4a, 4c Circumferential Surface 4b Axial One End Surface 4d Axial Other End Surface 7,9 Recess 7a, 9a Bottom 8 Through Hole 51 One Member 52 Other Member 53 Mounting Groove 54 Space 55 Low pressure side space

Claims (1)

[Claims] 1. A lip (2) which is mounted in an annular mounting groove provided in one of the two members that move relative to each other and is in close contact with the other member at one end in the axial direction, and the other in the axial direction. A packing including a packing body (1) having a stepped portion (3) on the peripheral surface on the end side and a backup ring (4) incorporated in the stepped portion (3), wherein the backup ring (4) is A recess (7) communicating with a space surrounded by the packing body (1), the backup ring (4) and the other member on one axial end surface (4b).
And a through hole (8) penetrating the backup ring (4) in the axial direction so as to be opened in the bottom surface (7a) of the recess (7).