JPH0451259Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an improvement of a lip seal that seals the outer periphery of a shaft of a device such as a compressor.

[Conventional technology]

A typical conventional example of this type of lip seal is disclosed, for example, in Japanese Patent Publication No. 30-3106.

As shown in FIG. 3, this lip seal has improved pressure resistance by attaching a metal reinforcing body 103 to the back surface of a lip member 101 made of an elastic body, excluding the tip 102. .

[The problem that the idea attempts to solve]

However, according to the above-mentioned conventional lip seal, as shown in FIG. 4 in its usage state, the tip 102 of the lip member 101 that projects into the sealed space A side in a tapered manner is in pressure contact with the outer circumferential surface of the shaft 105 and seals. The shaft 105 is deformed into a curved shape by the pressure P in the space A, and its inner periphery receives tensile stress.
Separation 102a is likely to occur between the surface of the lip member 101 facing the atmosphere B and the inner diameter end 104 of the metal reinforcing body 103 extending in a tapered shape, and the width of the sliding surface 106 with the outer peripheral surface of the shaft 105 increases (solid hit)
There is no denying that it is easy to do.

In this structure, in order to increase the pressure resistance of the lip member 101, it is effective to extend the inner diameter end 104 of the metal reinforcement 103 to the vicinity of the sliding surface 106. body 1
Since the inner diameter end 104 of 03 exists on the inner circumference of the tip 102 of the lip member 101, the inner diameter end 104 of the metal reinforcing body 103 will not interfere with the outer circumferential surface of the shaft 105 even if there is slight shaft vibration. Therefore, it is practically difficult to improve the pressure resistance by extending the inner diameter end portion 104.

Therefore, when the pressure P in the sealed space A increases, the tip 102 of the lip member 101 deforms and makes solid contact with the shaft 105, resulting in increased sliding heat generation due to excessive load and deterioration of the material due to this. Abnormal wear and other problems may occur.

The present invention was developed in view of these problems, and its purpose is to improve the pressure resistance of the lip member and maintain stable sealing performance over a long period of time.

[Means to solve the problem]

The above technical problems can be effectively solved by the present invention.

In other words, in the lip seal of the present invention, a metal reinforcing ring is bonded to the lip member in contact with the sealing liquid so as to cover the surface on the side of the sealed space excluding the tip, and the surface of the tip in contact with the sealing liquid is radially It is characterized by comprising a tapered outward pressure-receiving surface and an inward-facing pressure-receiving surface on the inner diameter thereof, which cancel out the pressure in the sealed space against each other.

[Effect]

According to the configuration of the present invention, the surface of the lip member on the sealed space side that is in contact with the sealing liquid is not subjected to the pressure of the sealed space due to the presence of the metal reinforcing ring. The lip member hardly bends toward the atmosphere, and the pressure in the sealed space acting on the tip of the lip member is balanced in the radial direction by the outward pressure receiving surface and the inward pressure receiving surface that are in contact with the sealing fluid. Therefore, even under high pressure conditions, the tip does not come into contact with the shaft.

[Embodiments] The present invention will be described below based on typical embodiments shown in the drawings.

The lip seal of the first embodiment shown in FIG.
A lip member 2 made of rubber is in contact with the refrigerant liquid (gas) that is the sealing liquid of the sealed space A and the refrigerating machine oil, and the air B
A lip member 3 made of synthetic resin such as PTFE on the side, a back-up spring 4 that supports this lip member 3 made of synthetic resin from the atmosphere B side, and both lip members 2, 3.
and a metal case 1 to which the outer diameter portion of the back-up spring 4 is fixed by caulking.

Then, the metal case 1 is airtightly attached to the inner circumferential surface 8 of the shaft hole of the housing 7 via the O-ring 5.
A lip member 2 made of a rubber material is fixed between the stepped portion of the inner circumferential surface 8 of the shaft hole and the snap ring 6 fitted into the groove of the inner circumferential surface 8 of the shaft hole, and is bent and extends toward the sealed space A side. The inner diameter sliding surface 10 of the tip portion 2' is
It is in sliding contact with the outer circumferential surface of the shaft 9 inserted into the shaft hole of the housing 7, and prevents the sealing fluid in the sealed space A, that is, the compressor, from leaking to the atmosphere B side.

A metal reinforcing ring 11 having a bent cross-sectional shape corresponding to the lip member 2 is adhered to the sealed space A side surface 2c of the rubber lip member 2 which is on the sealed space A side and comes into contact with the sealing liquid. ing. The tip end 2' of the lip member 2 is exposed to the sealed space A from the tip edge 11' of the metal reinforcing ring 11.
The ability to follow the radial displacement of the shaft 9 is ensured, and the liquid-contacted portion between the tip edge 11' of the metal reinforcing ring 11 and the sliding surface 10 has a structure that biases the pressure of the sealed space A toward the inner diameter direction. a tapered outward pressure receiving surface 2a on the outer diameter side that receives the pressure in the direction of the outer diameter, and a reverse taper on the inner diameter side that receives the pressure of the sealed space A in a direction biased toward the outer diameter direction and balances the pressure on the outward pressure receiving surface 2a. An inward pressure receiving surface 2b having a shape is formed.

The lip seal described above has a lip member 2 made of rubber material.
Since the metal reinforcing ring 11 is attached to the surface 2c on the side of the sealed space A, the lip member 2 as a whole will not be greatly bent toward the atmosphere B side by the pressure of the sealed space A. Moreover, the metal reinforcing ring 11
an outward pressure-receiving surface 2a of the tip portion 2' exposed from the
Since the pressures Pa and Pb of the sealed space A acting on the inward pressure receiving surface 2b of the inner diameter are balanced in the radial direction,
Even if the pressure in the sealed space A becomes high, the tip portion 2' will not be strongly pressed toward the inner diameter side and will not come into solid contact with the outer circumferential surface of the shaft 9.

Therefore, even under high pressure conditions, the sliding surface 10 on the inner diameter of the tip 2' of the rubber lip member 2 and the shaft 9
It is possible to prevent an increase in heat generation and an increase in the amount of wear due to the sliding load on the outer circumferential surface of the metal reinforcing ring 11 when the tip portion 2' is caused by the pressure Pa from the outer circumference side.
It will not peel off from the leading edge 11'.

Note that since the tip edge 11' of the metal reinforcing ring 11 is located on the outer peripheral side of the rubber lip member 2, the reinforcing ring 11 does not interfere with the outer peripheral surface of the shaft 9.

Next, the lip seal of the second embodiment shown in FIG. 2 is provided with a circumferential recess 12 extending along the inner circumference of the tip edge 11' of the metal reinforcing ring 11 in the rubber lip member 2. Particularly, the tip portion 2' having the sliding surface 10 is formed so as to branch toward the inner diameter side, and the outward pressure receiving surface 2a formed by the recess 12 and the inward pressure receiving surface on the inner diameter side thereof are formed. Side 2
The configuration is such that the pressure is balanced in the radial direction by b, and the same effects as in the first embodiment can be obtained. Furthermore, the structure is such that peeling of the tip edge 11' of the metal reinforcing ring 11 and the rubber lip member 2 due to the pressure in the sealed space A is less likely to occur.

[Effect of idea]

As explained above, according to the lip seal of the present invention, the reinforcing ring is bonded to the surface of the lip member on the side of the sealed space, and the pressure is balanced in the radial direction at the tip having a sliding surface with the shaft. The sliding surface of the inner diameter of the tip does not contact the outer peripheral surface of the shaft, the reinforcing ring does not interfere with the outer peripheral surface of the shaft, and the lip member does not separate from the reinforcing ring due to the pressure. . Therefore, pressure resistance is improved, problems such as abnormal heat generation and reduced sealing performance can be eliminated, and stable performance can be maintained for a long period of time even under high pressure conditions.

[Brief explanation of drawings]

Fig. 1 is a half-cut sectional view showing the first embodiment of the present invention in a used state, Fig. 2 is a half-cut sectional view showing the second embodiment in a used state, and Fig. 3 is a partial sectional view showing a conventional example. FIG. 4 is a half-cut sectional view showing a state in which a problem occurs during use of the conventional example. DESCRIPTION OF SYMBOLS 1...Metal case, 2...Lip member in contact with sealing liquid, 2'...Tip part, 2a...Outward pressure receiving surface,
2b...Inward pressure receiving surface, 7...Housing, 9...
...Shaft, 10...Sliding surface, 11...Metal reinforcement ring, A...Sealed space.

Claims (1)

[Scope of utility model registration request] Among one or more lip members that extend bent toward the sealed space side and whose tip inner periphery slides into contact with the shaft outer circumferential surface, the lip member that comes into contact with the sealing fluid is provided with a metal so as to cover the surface of the sealed space side excluding the tip. A reinforcing ring is bonded thereto, and the surface of the tip that comes into contact with the sealing liquid is comprised of a tapered outward pressure receiving surface that cancels out the pressure of the sealed space in the radial direction, and an inward pressure receiving surface of the inner diameter thereof. Lipstick.