JPH08135795A - Sealing device - Google Patents

Abstract

PURPOSE: To prevent damages to a sealing device due to the partial extrusion thereof into a mounting gap between members via the use of a backup ring, and simplify dimensional accuracy for machining the ring. CONSTITUTION: This sealing device is fitted to a mounting groove 6 formed on one of opposite two members 3 and 4, and has an annular seal 1 of rubber type elastic material, and an annular backup ring 2 laid at a position opposite to the side of the member 1 where a hydraulic fluid acts, and made of harder material than the seal 1. Furthermore, the side 11 of the ring 2 is formed, so that one end thereof parts from the bearing surface 5 of the groove 6, even when the other end comes in contact therewith. Also, the side 11 of the ring 2 is formed to be elastic, so as to be capable of elastic deformation under exposure to the pressure of a hydraulic fluid for enabling the separated section thereof to be jointed to the surface 5.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a sealing device. In particular, the present invention relates to a fixing or exercising seal device that prevents the seal portion from being damaged in the gap between the first member and the second member.

[0002]

2. Description of the Related Art As a prior art relating to the present invention, an actual flat blade
-62964 publication exists. This publication describes the sealing device shown in FIG.

FIG. 4 is a sectional view of this sealing device.
In FIG. 4, a mounting groove 33 is formed in the piston 31 fitted into the cylinder tube 32. This mounting groove 3
3, a back ring 34 is fitted and a piston seal 35 is fitted to the outer peripheral surface of the back ring 34. Since this piston seal 35 is made of a soft material, it lacks elasticity. For this reason, the piston seal 35 is elastically supported by the rubber back ring 34 so as to come into pressure contact with the cylinder tube 32.

Even if the piston seal 35 is made of a soft material, it is elastically deformed in order to exert a sealing effect. Moreover, the seal surface is pressed against the mating sliding surface.

FIG. 5 is a sectional view of a sealing device showing another conventional technique. In FIG. 5, the hole 43 of the housing 41
The housing 41 between the shaft 42 and
A mounting groove 44 for the sealing device 40 is formed.

The seal device 4 fitted in the mounting groove 44
Reference numeral 0 is composed of an O-ring 45 made of a rubber material and a backup ring 46 arranged on one surface of the O-ring 45. The backup ring 46 is the O ring 45.
Made of harder material. Then, it is a ring-shaped body having a Γ-shaped cross section.

[0007]

In the prior art configured as described above, the seal device shown in FIG. 4 must have elasticity because the piston seal 35 needs to be in close contact with the cylinder tube 32. Therefore, when the working fluid pressure is received, a part of the piston seal 35 is
Fitting gap 36 between cylinder tube 32 and piston 31
This causes the problem of protrusion and damage to the protrusion. Further, if the piston seal 35 is hardened, it is necessary to insert it into the mounting groove 33, so that it is necessary to cut a part of the ring to form the divided portion 37. Therefore, this causes a problem that the fluid flows out from the divided portion 37.

If the piston seal 35 is made hard,
Even if it is elastically supported by the back ring 34, there is a drawback that the sealing effect is lowered.

As a means for solving such a problem,
There is a sealing device shown in FIG. In this sealing device, when the working fluid pressure is applied to the O-ring 45, a part of the O-ring 45 protrudes into the gap between the housing 41 and the shaft 42, and this is intended to be prevented by the backup ring 46.

However, if the gap between the backup ring 46 and the shaft 42 is increased, a problem similar to that of the sealing device shown in FIG. 4 occurs. On the other hand, if the gap is made smaller, the operating pressure acts on the O-ring, and the backup ring receives all the accumulated pressure, so that the backup ring 46 is extended in the radial direction to tighten the shaft. The backup ring 46 will be damaged.

Therefore, when the backup ring 46 is processed, it is extremely difficult to obtain the accuracy because it is necessary to consider the operating pressure and the thermal dimensional change. In particular, since the backup ring made of a resin material changes in size due to the influence of heat, its processing accuracy is more difficult.

The present invention has been made in view of the above-mentioned problems of the prior art. Its purpose is to simplify the dimensional accuracy of the backup ring and prevent the seal portion from protruding into the member gap. To do.

[0013]

The present invention has been made in order to achieve the above-mentioned object, and its technical means is constituted as follows. That is, the seal device is attached to the mounting groove provided in one of the two opposing members, and is a ring-shaped seal portion made of a rubber-like elastic material and opposite to the side on which the working fluid acts on the seal portion. Has a ring-shaped backup ring that is harder than the seal portion, and the side surface of the backup ring has a shape in which one end of the side surface is in contact with the supporting side surface of the mounting groove, but the other end is separated. The elastic body is formed and elastically deformed by the pressure of the working fluid so that the distant side of the side surface can be joined to the support side surface.

[0014]

When the working fluid pressure acts on the sealing device, the sealing portion seals the working fluid by the rubber-like elastic force. At this time, the seal portion receives the pressure of the working fluid and is pressed against one side surface of the mounting groove, but is supported by a hard and elastically deformable backup ring. Then, all the side surfaces of the backup ring are deformed until they are joined to the supporting side surfaces of the mounting groove and extend in the radial direction to prevent a part of the seal portion from protruding into the gap between the members.

[0015]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a cross-sectional view in which the sealing device according to the present invention is mounted in a mounting groove. 1 is a seal part. The seal portion 1 is made of a rubber-like elastic material and is formed as an O-ring. A backup ring 2 is arranged in parallel on the side surface of the seal portion 1. The sealing unit 1 and the backup ring 2 constitute a sealing device 10.

The seal portion 1 is made of a rubber material or a resin material having elasticity. In the case of rubber materials, acrylic, nitrile rubber, etc. are also used depending on the type of working fluid. In the case of a resin material, an elastic plastic material such as polyester resin or polyolefin resin is also used. The seal portion 1 has an annular shape and is O-shaped in cross section, but various types such as D-shaped, elliptical, quadrangular, and U-shaped can be used.

The backup ring 2 forms an annular body,
The cross section is formed into a parallelogram as shown in the figure. The length of one side H0 of the backup ring 2 is formed slightly larger than the depth H1 of the mounting groove. That is, the length of one side H0 of the backup ring 2 is a dimension to be joined to the outer peripheral surface of the second member 4 when the backup ring is deformed into a quadrangle.

The material of the backup ring 2 is set by the operating pressure. Backup ring 2 shown in FIG.
At a low pressure, is harder than the seal portion 1 and is made of, for example, elastic plastic or fluororesin material.

The sealing device 10 composed of the sealing portion 1 and the backup ring 2 is mounted in the mounting groove 6 formed in the first member 3 as shown in FIG.

FIG. 2 shows another embodiment of the arrangement of the backup ring 2 according to the present invention. In FIG. 2, the first member 3 is a piston and is attached to the mounting groove 6. The backup ring 2 has the shape shown in FIG. 1 and is arranged on both sides of the seal portion 1. Other shapes are almost the same as the backup ring 2 in FIG.
Note that the backup rings 2 may be symmetrically arranged on both sides of the seal portion 1 unlike FIG. A hard elastic member 13 is embedded in the seal portion 1 in an inclined state.

FIG. 3 shows still another embodiment according to the present invention. The backup ring 2 shown in FIG. 3 has a high pressure. The backup ring 2 is formed by two reinforcing portions 8 and an elastic portion 9 that joins the reinforcing portions 8.
The elastic portion 9 is harder than the seal portion 1. Also, the reinforcing portion 8
Is harder than the elastic portion 9. And the whole is an annular body, and the cross section is formed in a substantially parallelogram shape. This cross-sectional shape may be formed so as to be symmetrical in the radial direction with respect to the backup ring 2 shown in FIG.

The sliding portion of the reinforcing portion 8 of the backup ring 2 facing the opposing member (second member) is chamfered by the arc portion 12. Further, the bottom surface side of the mounting groove 6 has an elastic portion 9 '.
Is wrapping around.

The elastic portion 9 is made of a rubber material or an elastic plastic material. The reinforcing portion 8 is made of plastic material, oil-impregnated sintered metal, aluminum material, copper material, or the like.

Since the reinforcing portion 8 fits into the mounting groove,
You may divide one part of a ring. Then, it is integrally molded with the elastic portion 9. Further, the reinforcing portion 8 and the elastic portion 9 may be assembled without bonding.

Although the above-described embodiment is a motion sealing device, it can also be used as a stationary sealing device. Further, when the first member 3 and the second member 4 are joined to a flat surface, an annular mounting groove 6 is formed along the flat surface, and a sealing device is also formed on the flat surface so as to be mounted in the mounting groove 6. It is also possible to do so.

According to the present invention constructed as described above, when it is mounted in the mounting groove 6 and receives the pressure of the working fluid, the seal portion 1 is crushed by the pressure toward the supporting side surface 5 side of the mounting groove 6. Then, due to this pressing force, the backup ring 2
The whole is deformed into a shape that is joined to the supporting side surface and becomes large in the radial direction, supports the seal portion 1, and closes the gap 7 between the first member 3 and the second member 4. Therefore, the seal portion 1
Does not enter the gap.

[0028]

EFFECTS OF THE INVENTION Since the side surface of the elastic backup ring of the present invention is formed such that one end has a gap with respect to the supporting side surface of the mounting groove, when the pressure of the working fluid is applied, the entire side surface is opened. Elastically deforms in the direction of joining to the supporting side surface. At this time, the sliding side of the backup ring with respect to the mating member is deformed in the direction of reducing the gap as it is deformed. Therefore, the effect of preventing the seal portion from entering the gap between the first member and the second member by reducing the gap with the mating member of the backup ring can be expected. As a result, even if the dimensional accuracy of the backup ring is not precisely machined, a superior effect can be achieved than ever before. or,
The seal portion can be elastically supported and deformed by the backup ring even when subjected to a high pressure of the working fluid, so that the seal portion can be prevented from being cracked or damaged by a sudden force.

[Brief description of drawings]

FIG. 1 is a sectional view of an essential part of a sealing device according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view of essential parts of a sealing device according to another embodiment of the present invention.

FIG. 3 is a sectional view of a main part of a backup ring according to still another embodiment of the present invention.

FIG. 4 is a sectional view of a main part of a conventional sealing device.

FIG. 5 is a cross-sectional view of the main parts of another conventional sealing device.

[Explanation of symbols]

 1 ... Seal part 2,46 ... Backup ring 3 ... First member 4 ... Second member 5 ... Supporting side surface 6,33 ... Mounting groove 7 ... Gap 8 ... Reinforcement part 9 ... Resilient part 9 '... Elastic part 10, 30, 40 ... Sealing device 11 ... Side surface 12 ... Arc part 13 ... Elastic member 31 ... Piston 32 ... Cylinder tube 34 ... Back ring 35 ... Piston seal 36 ... … Gap 37 …… Split part 41 …… Housing 42 …… Shaft 43 …… Hole 44 …… Mounting groove 45 …… O ring

Claims (1)

[Claims] 1. A seal device which is attached to a mounting groove (6) provided in one member of two members (3, 4) facing each other, and which is a ring-shaped seal portion made of a rubber-like elastic material. 1) and a backup ring (2), which is arranged on the side opposite to the side on which the working fluid acts on the seal portion (1) and has an annular shape that is harder than the seal portion (1). The side surface (11) of the ring (2) is formed such that even if one end of the side surface (11) is in contact with the supporting side surface (5) of the mounting groove (6), the other end is separated from the supporting side surface (5). It is characterized in that the seal portion (1) which receives the pressure of the working fluid is elastically deformed by being pressed and the distant side of the side surface (11) is an elastic body that can be joined to the supporting side surface (5). Sealing device.