JP2001027328A - Lip shaped seal - Google Patents

Abstract

PROBLEM TO BE SOLVED: To ensure a good contacting state with reference to a rotation shaft by preventing a second seal member from pushing out a seal lip of a first seal member to a sealed space. SOLUTION: A projection engaged into a border position between a clipped portion 131 and a bending portion 132 of a second seal member 13 is provided on a flange portion of a metal ring 11. The second seal member 13 is easily bent and expanded using an engaging part of the projection as a starting point at the time of being attached to an outer periphery of a rotation shaft 2, so that the generation of stress urging a seal lip 133 of the second seal member 13 to displace to a sealed space A can be suppressed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technology for improving the sealing performance of a lip-type seal for sealing various rotating devices by stabilizing a sealing member made of synthetic resin.

[0002]

2. Description of the Related Art A lip seal 100 as shown in FIG. 3 has conventionally been used as a shaft sealing device used in a compressor or the like. This type of lip seal 100 includes a cylindrical portion 101a.
And a metal ring 101 composed of a flange portion 101b extending from the end on the atmosphere B side to the inner peripheral side, and an outer peripheral base 102b closely contacted with the inner peripheral surface of the housing 1.
01 is integrally vulcanized and bonded to the cylindrical portion 101a, and the inner end of the seal lip 102a extending from the inner periphery to the sealed space A via the radial portion 102c is sealed to the outer peripheral surface of the rotary shaft 2. First sealing member 1 made of elastomer to be in sliding contact
02 and the clamped portion 103b on the outer periphery are
1b and a radial portion 102c of the first seal member 102
The seal lip 103a is bonded to the flange portion 101b while being sandwiched between the first seal member 102 and the seal lip 103a extending from the inner periphery to the sealed space A via the bent portion 103c. PT which is more in sliding contact with the outer peripheral surface of the rotating shaft 2 on the atmosphere side
A second seal member 103 made of a synthetic resin such as FE.

[0003]

The above-mentioned lip seal 1
Reference numeral 00 denotes a mounted state as shown in FIG. 3, in which the seal lips 102 of the first and second seal members 102 and 103 are mounted.
The fluids a and 103a are in sliding contact with the outer peripheral surface of the rotating shaft 2 to seal the fluid to be sealed in the sealed space A.

However, according to the conventional structure, the rotating shaft 2
At the time of attachment to the outer periphery, the seal lip 103a of the second seal member 103 is expanded in diameter to generate a tensile force on the back side, so that the clamped portion 103b of the second seal member 103 and the metal ring 101 Flange portion 101
If there is a variation in the adhesion between the sealing lip 103 and the sealing lip 103, as shown in FIG.
In a, the sliding contact position with the rotating shaft 2 may move to the sealed space A side from the set position (the position shown in FIG. 3). In this case, the head of the seal lip 102a in the first seal member 102a is pushed by the second seal member 103a from the back side to expand the diameter, and the close contact load with the outer peripheral surface of the rotating shaft 2 decreases. It is pointed out that the sealing performance is reduced due to the occurrence of the gap G2.

As a method for preventing this, it is conceivable to shorten the seal lip 103a of the second seal member 103.
In addition to the decrease in the sliding seal area of the first sealing member 10a in the normal mounting state shown in FIG.
The distance L from the second seal lip 102a to the seal lip 102a becomes large, and the seal lip 102a tends to be solid on the outer peripheral surface of the rotating shaft 2 at high pressure.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and a main technical problem thereof is to stabilize a second seal member in a state of being mounted on the outer periphery of a rotating shaft. Thereby, the seal lip of the first seal member is brought into a good contact state with the rotating shaft.

[0007]

As a means for effectively solving the above-mentioned technical problems, a lip-type seal according to the present invention comprises a metal ring having a flange portion extending at one end in the axial direction toward the inner periphery. A first seal member made of an elastomer and having an inner diameter side sealing lip extending to the sealed space side sealingly slidingly contacting the outer peripheral surface of the rotating shaft; and a first seal member made of a synthetic resin material, the flange portion and the first seal member. An outer peripheral surface of the rotating shaft, which extends from the inner periphery thereof to the sealed space side via the bent portion to the sealed space side from the seal lip of the first seal member, and which is sandwiched between the outer periphery of the seal lip and the inner periphery thereof; A second seal member having a seal lip that is sealingly slidably contacted with the second seal member, and the flange portion has a protrusion that cuts into a boundary position between a pinched portion and a bent portion of the second seal member. It is. Therefore, the second seal member is easily bent and expanded from the biting portion of the projection when mounted on the outer periphery of the rotating shaft, so that the seal lip of the second seal member is displaced toward the sealed space. The generation of such stress is suppressed.

[0008]

FIG. 1 is a half sectional view showing an embodiment of a lip seal according to the present invention, taken along a plane passing through an axis, in an unmounted state, and FIG. 2 is a half sectional view in the same mounted state. FIG. The lip seal 10 includes a metal ring 11, a first seal member 12, and a second seal member 13.

The metal ring 11 includes a cylindrical portion 111 and a flange portion 112 extending inward from an end on the atmosphere B side, and the cylindrical portion 111 has a relatively large diameter at the flange portion 112 side. And a step portion 111a that is continuous in the circumferential direction so that

The first seal member 12 includes a base 121 formed by embedding and integrating the cylindrical portion 111 of the metal ring 11, a radial portion 122 extending from an intermediate position in the axial direction to the inner peripheral side, A seal lip 123 extends from 122 to the side opposite to the flange 112 of the metal ring 11 (toward the sealed space A), and is vulcanized and formed of an elastomer material.

In the base 121 of the first seal member 12, a thick portion formed on the outer periphery of the cylindrical portion 111 of the metal ring 11 on the small diameter side of the step portion 111 a is closely fitted to the inner peripheral surface of the housing 1. A required number of circumferentially continuous sealing ridges 121a are formed to enhance the sealing performance. Further, the seal lip 123 of the first seal member 12 has a head 123 a at the distal end thereof, which has a rotating shaft 2 inserted through the housing 1.
And is slidably contacted with the outer peripheral surface of the main body.

The second seal member 13 includes a flange portion 112 of the metal ring 11 and a radial portion 12 of the first seal member 12.
2 and a bent portion 132 which is adhered to the flange portion 112 in a state where the bent portion 132
And a seal lip 133 extending on the inner peripheral side of the first seal member 12 to the side opposite to the flange portion 112 of the metal ring 11 (on the side of the sealed space A) through the seal ring 133, and is formed of a synthetic resin material such as PTFE. I have. In addition, the second sealing member 1
Reference numeral 3 denotes an integrated member shown in FIG. 1 which is disposed together with the metal ring 11 in a molding die when the first seal member 12 is vulcanized.

A protrusion 113 protruding toward the second seal member 13 is provided on a flange 112 of the metal ring 11.
Are continuously formed in the circumferential direction. The protrusion 113 is fitted in a recess 134 formed on the back surface of the boundary between the held portion 131 and the bent portion 132 in the second seal member 13. In such a structure, when the first seal member 12 is vulcanized and formed, the protrusion 113 cuts into the back surface of the boundary position of the heat-softened second seal member 13 due to the molding pressure. It is formed by:

The lip seal 1 constructed as described above
0 is a seal mounting step 1a in which the flange 112 of the metal ring 11 is formed on the housing 1 as shown in FIG.
Is mounted on the housing 1 so as to be in contact with the housing 1. In this mounted state, the seal ridge 121 a formed on the outer peripheral surface of the base 121 of the first seal member 12 made of the elastomer is attached to the cylindrical portion 111 of the metal ring 11.
And is held in a non-rotating state by being pressed against the inner peripheral surface of the housing 1 with an appropriate close load.

On the other hand, the head 123a of the seal lip 123 in the first seal member 12 is brought into sliding contact with the outer peripheral surface of the rotary shaft 2 all around, and the seal lip 133 in the second seal member 13 is The atmosphere B is higher than the head 123a of the seal lip 123 in the seal member 12.
On the side, the entire circumference is in sliding contact with the outer peripheral surface of the rotating shaft 2. Then, in the mounted state shown in FIG.
3 is the first seal member 12
, The seal lip 123 of the first seal member 12 and the seal lip 133 of the second seal member 13 are moved from the inner peripheral side when the sealed space A becomes high pressure. Bearing, the head 12
It also has a function of preventing the outer peripheral surface of the rotary shaft 2 from coming into solid contact with the outer peripheral surface of the rotating shaft 2.

The lip-type seal 10 is mounted on the outer periphery of the rotary shaft 2 in a state shown in FIG. 1 as the diameter of the seal lip 133 of the second seal member 13 is increased from the original shape. From the state shown in FIG. At this time, the boundary portion between the pinched portion 131 and the bent portion 132 in the second seal member 13 is made thin by the biting of the projection 113 formed on the flange portion 112 of the metal ring 11, so that this portion is formed. , The bending deformation accompanying the diameter expansion is easily performed, and the second sealing member 1
No large stress is generated in 3. For this reason, the second seal member 13 is effectively prevented from moving the seal lip 133 toward the sealed space A side by the reaction force against the deformation, and as a result, the seal lip 123 of the first seal member 12 is prevented from moving. The head 123a is not pushed by the second seal member 13 from the back side to expand the diameter, and a good sealing performance is secured.

[0017]

As described above, according to the lip-type seal of the present invention, the second seal member on the atmosphere side made of a synthetic resin material seals the head of the seal lip of the first seal member made of an elastomer. Since there is no adverse effect on the close contact with the rotating shaft by being pushed to the space side, excellent sealing performance can be ensured.

[Brief description of the drawings]

FIG. 1 shows an embodiment of a lip seal according to the present invention;
FIG. 5 is a half sectional view of an unmounted state shown cut along a plane passing through an axis.

FIG. 2 is a half sectional view of the mounted state, showing the embodiment cut along a plane passing through an axis.

FIG. 3 is a half sectional view showing a mounted state of a lip-type seal according to the related art, which is cut along a plane passing through an axis.

FIG. 4 is a half cross-sectional view showing a state in which a defect has occurred in the above-described conventional technique, cut along a plane passing through an axis.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Housing 2 Rotation shaft 10 Lip type seal 11 Metal ring 112 Flange part 113 Projection part 12 First seal member 123, 133 Seal lip 13 Second seal member 131 Clamped part 132 Bent part A Sealed space B Atmosphere

Claims (1)

[Claims] 1. A metal ring having an axially-extending flange portion at one end in an axial direction, a seal lip made of an elastomer and extending toward a sealed space on an inner diameter side sealingly slidingly contacting the outer peripheral surface of the rotating shaft. A sealing member, which is made of a synthetic resin material, is sandwiched between the flange portion and the outer peripheral portion of the seal lip of the first sealing member, and from the inner periphery thereof to the sealed space side via the bent portion; A second sealing member having a sealing lip extending and sealingly slidingly contacting the outer peripheral surface of the rotary shaft on the side opposite to the sealing space from the sealing lip of the first sealing member; A lip seal having a projection biting into a boundary position between the held portion and the bent portion of the seal member.