JPH03265766A - Lip seal device - Google Patents

Abstract

PURPOSE:To prevent a generation of fluid leakage when a rorary shaft is stopped as well as to obtain an antiabrasive property of a lip by providing a seal member made of a rubber in a circular groove formed on the seal surface of a lip made of a synthetic resin. CONSTITUTION:When a compressor is operated, the inner circumferential surface of a seal member 10 is separated from the outer circumferential surface of rotary shaft 2 because the pressure of the sealing fluid is low and the elastic deformation amount of a thin thickness part 6a of a lip 6 is small. As a result, the seal member 10 made of a rubber whose antiabrasive property is little is never abraded by the rotation of the rotary shaft 2. On the other hand, a sufficient sealing function can be obtained by the double sealing with both side parts 9b and 9c of a circular groove 9. And when the compressor is stopped, the pressure of the sealing fluid is increased, thereby the thin thickness part 6a is deformed largely, and the inner circumferential surface of the seal member 10 in the circular groove 9 is contacted closely to the outer circumferential surface of the rotary shaft 2. But in this case, since the rotation of the rotary shaft 2 is stopped, no abrasion of the seal member 10 is generated, and even though the adhesive property of the lip 6 is not good, the adhesive property of the seal member 10 is good and a sufficient sealing function can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION "Field of Industrial Application" The present invention relates to a lip seal device having a lip that slides on a rotating shaft, and particularly to a lip seal device suitable for use in a compressor.

"Prior Art" Conventionally, a lip seal device has a case that surrounds a rotary shaft that is rotatably supported, an outer peripheral part is attached to the case, and an inner peripheral part is curved toward the sealing fluid side. There is a known device comprising a lip made of synthetic resin that is in sliding contact with the outer peripheral surface of the rotating shaft, and an annular groove that is formed on the sealing surface of the lip with the rotating shaft and that is continuous in the circumferential direction of the rotating shaft. There is (
JP-A-1-112082).

In addition, in a type of compressor in which the sealing device is placed on the low-pressure fluid side, the pressure of the sealed fluid near the sealing device sealed by the lip seal is higher when the compressor is stopped than when the compressor is operating, that is, when the rotating shaft is It is known that the value is higher when the motor is stopped than when it is rotating.

``Problems to be Solved by the Invention'' By the way, synthetic resins and rubbers having low friction and high wear resistance such as PT and FE are used as the material for the lip, but it is difficult to use a rubber lip. When used, the pressure of the sealing fluid makes it adhere well to the outer peripheral surface of the rotating shaft, so good sealing performance can be obtained when the rotating shaft is stopped.
It has the disadvantage of low wear resistance and low heat resistance.

On the other hand, when using a synthetic resin lip, greater wear resistance can be obtained compared to when using a rubber lip, but even under the pressure of the sealing fluid, the outer peripheral surface of the rotating shaft Since the degree of adhesion is inferior to that of the rubber lip, there is a risk of leakage, especially when the rotating shaft is stopped.

In view of such circumstances, the present invention provides a lip seal device that uses a lip made of synthetic resin to obtain high wear resistance and at the same time prevents leakage when the rotating shaft is stopped. It is something to do.

``Means for Solving the Problems'' That is, the present invention provides a lip seal device including a lip made of synthetic resin and having an annular groove formed on the sealing surface of the lip, in which a rubber sealing member is disposed within the annular groove. It was established.

"Function J When the lip seal device with the above configuration is used in a car compressor, when the rotation of the rotating shaft with high sealing fluid pressure is stopped, the wall thickness of the annular groove part of the lip becomes thinner than other parts. Therefore, the thin wall portion is easily compressed and deformed by the pressure from the sealing fluid side, and as a result, the seal member in the annular groove comes to be in close contact with the outer circumferential surface of the rotating shaft.As a result,
Leakage when rotation is stopped can be effectively prevented.

On the other hand, since the pressure of the sealing fluid decreases when the rotating shaft rotates, the large amount of pressure deformation of the annular groove portion of the lip is reduced, which reduces the adhesion force between the sealing member in the annular groove and the rotating shaft. , or the sealing member becomes separated from the rotating shaft.

Therefore, when the rotary shaft rotates, it is possible to prevent the sealing member from being worn out and to obtain a sealing effect by the synthetic resin lip having high wear resistance.

``Embodiment'' The present invention will be described below with reference to an illustrated embodiment. In FIG. 1, a rotating shaft 2 is rotatably supported by passing through a stepped hole 1a formed in a housing 1 of a car compressor.
A lip seal device 3 according to the present invention seals between the inner peripheral surface of the stepped hole 1a and the outer peripheral surface of the rotating shaft 2. In a car compressor of the type in which the lip seal device 3 is disposed on the low pressure fluid side, the lip seal device 3 is
For example, the pressure of the sealing fluid in the part sealed by the rotating shaft 2 is 1 to 2 kg/cm2 when the rotating shaft 2 is rotating, and 4 to 6 kg/cm2 when the rotating shaft 2 is stopped, and is higher when the rotating shaft is stopped than when it is rotating. It's starting to get expensive.

The lip seal device 3 includes a metal case 4, a rubber elastic member 5 vulcanized and bonded to the case 4, and a PTF
It includes a lip 6 made of a synthetic resin material having low friction and high wear resistance such as E, and a spacer 7 made of metal.

The case 4 is formed into a ring shape so as to surround the rotating shaft 2, and its axial cross-sectional shape includes a cylindrical portion 4a extending in the axial direction and flanges extending radially inward from both ends of the cylindrical portion 4a. The portions 4b and 4C form a substantially U-shaped cross section.

Further, the elastic member 5 is provided so as to cover continuously from the outer circumferential side of the cylindrical portion 4a, the outer and inner portions of the flange portion 4b, and further the inner circumferential side of the cylindrical portion 4a.

The radially outer circumferential portion of the lip 6 includes the inner portion of the flange portion 4b of the elastic member 5 and the cylindrical portion 4a.
The lip 6 is brought into contact with a portion covering the inner circumferential portion of the lip 6, and is integrally connected to the case 4 in a fluid-tight manner by a spacer 7 disposed between the outer circumferential portion of the lip 6 and the flange portion 4C.

Furthermore, the inner circumferential portion of the lip 6 is curved so as to protrude toward the sealed fluid side, that is, to the left, and the inner circumferential surface side of the protruding portion is brought into elastic contact with the outer circumferential surface of the rotating shaft 2 by its own elasticity. , the sealing fluid present on the left side of the lip 6 is prevented from leaking to the atmosphere side on the right side.

At this time, the inner peripheral portion of the spacer 7 may be curved toward the sealing fluid side, and the lip 6 may be curved toward the sealing fluid side along the curvature of the spacer. Alternatively, the inner circumferential surface of the elastic member 5 may be brought into close contact with the sealed fluid side surface of the lip 6, and the inner circumferential surface of the lip 6 may be brought into elastic contact with the outer circumferential surface of the rotating shaft 2 due to the elasticity of the elastic member 5. good.

Then, an annular groove 9 continuous in the circumferential direction of the rotating shaft 2 is formed on the sealing surface of the lip 6 with the rotating shaft 2, and
A sealing member 10 made of a rubber O-ring having an appropriate shape such as a circular or trapezoidal cross section is provided within the annular groove 9.

As shown in FIG. 2, the outer diameter of this sealing member IO is in contact with the bottom surface 9a of the annular groove 9, and the inner diameter is slightly larger than the diameter of the rotating shaft 2. , in a natural state where no pressure is applied, it does not come into close contact with the outer circumferential surface of the rotating shaft 2.

According to the above structure, since the annular groove 9 is formed in the sealing surface of the lip 6, the wall thickness of the lip 6 becomes thinner at that portion, and the thin walled portion 6a is deformed when receiving the pressure of the sealing fluid. become more susceptible to As a result, both side portions 9 of the annular groove 9
b and 9C are relatively pressed against the outer circumferential surface of the rotating shaft 2, and both side portions thereof come into contact in a continuous line or band shape in the circumferential direction.

During operation of the compressor shown in FIG. The circumferential surface is maintained separated from the outer circumferential surface of the rotating shaft 2. As a result, the rubber sealing member 10 with low wear resistance is not worn out by the rotation of the rotary shaft 2, and on the other hand, the double seal provided by the both side portions 9b and 9c of the annular groove 9 provides sufficient sealing action. is obtained.

On the other hand, when the compressor is stopped as shown in FIG. The inner circumferential surface of the member 10 comes to be in close contact with the outer circumferential surface of the rotating shaft 2. In this state, the rotation of the rotating shaft 2 is stopped, so the sealing member IO is not worn out, and even if the synthetic resin lip 6 has poor adhesion, the rubber sealing member IO has good adhesion. Therefore, a sufficient sealing effect can be obtained even when the rotating shaft 2 stops rotating.

In the above embodiment, the inner circumferential surface of the seal member 10 is separated from the outer circumferential surface of the rotating shaft 2 in the natural state. It may be made to adhere lightly to the surface.

"Effects of the Invention" As described above, according to the present invention, when the rotation of the rotating shaft is stopped, such as in a car compressor where the pressure of the sealed fluid is high, the sealing member in the annular groove is in close contact with the outer peripheral surface of the rotating shaft. This can effectively prevent leakage, and when the rotary shaft rotates when the pressure of the sealed fluid is low, the adhesion between the seal member and the rotary shaft can be reduced or separated, reducing wear on the seal member. In addition to being able to prevent leakage, the double seal provided by both side portions of the annular groove provided on the sealing surface provides the effect that leakage can be effectively prevented.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing one embodiment of the present invention, and FIG.
FIG. 3 is an enlarged cross-sectional view of the main part of the figure, and FIG. 3 is a cross-sectional view showing a state different from that in FIG. 2. 1... Housing 3... Lip seal device 5... Outer seal member 9... Annular groove 2... Rotating shaft 4... Case 6... Lip 10... Seal member

Claims (1)

[Claims] A case surrounding a rotating shaft that is rotatably supported;
A synthetic resin lip whose outer peripheral part is attached to the case and whose inner peripheral part is curved toward the sealed fluid side and comes into sliding contact with the outer peripheral surface of the rotating shaft, and formed on the sealing surface of the lip with the rotating shaft. A lip seal device comprising an annular groove continuous in the circumferential direction of a rotating shaft, characterized in that a rubber seal member is provided in the annular groove.