JP2532010Y2 - Lip type seal - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a lip seal for sealing the circumference of a rotating shaft.

[0002]

2. Description of the Related Art Conventionally, for example, as shown in FIG.
A rubber material lip member 2 on the sealed space A side is provided on the inner periphery of the metal case 1 tightly fixed to the shaft hole via an O-ring 7.
A PTFE lip member 3 on the side of the anti-sealed space (atmosphere) B,
A metal backup ring 4 for supporting the PTFE lip member 3 from the side of the non-sealing space B and a dust lip member 5 on the side of the non-sealing space B are held in a state where their outer diameters are in close contact with each other. A lip-shaped seal with a different structure is used.

In this lip type seal, the inner ends 21 and 31 of the rubber lip member 2 and the PTFE lip member 3 extending in a curved manner toward the sealed space A are in air-tight sliding contact with the outer peripheral surface of the shaft 8, so that the sealed space is provided. A for preventing the refrigerant in A and the refrigerating machine oil from leaking into the anti-sealed space B, that is, the atmosphere.
The inner diameter end 31 of the PTFE lip member 3 supports the waist 22 near the inner diameter end 21 of the rubber lip member 2 from the inner peripheral side, and the waist 22 and the inner diameter end 21 are pressed by the pressure of the sealed space A. It suppresses collapse and deformation.

[0004]

In this type of lip seal, the inner peripheral surface of the inner end portion 31 of the PTFE lip member 3 slides in a cylindrical shape with respect to the outer peripheral surface of the shaft 8. The sliding surface 33 is in sliding contact with the moving surface 33, and the sliding surface 33 is in sliding contact with the rubber material lip member 2 while receiving the pressure of the sealed space A via the waist portion 22. Some of this heat is released through the shaft 8, the backup ring 4 and the case 1.

However, according to the above-mentioned conventional structure, the inner peripheral surface of the waist portion 22 of the rubber lip member 2 is in close contact with the outer peripheral surface of the inner diameter end portion 31 which generates heat due to the pressure of the sealed space A. A large amount of heat is short-circuited to the inner diameter end 21 of the rubber lip member 2 from the inner rim member 22. Accordingly, the inner diameter end 21 of the rubber lip member 2 generates not only its own sliding heat but also the PTFE lip member. There was a problem that elasticity was reduced by heat from the third side, cracks were generated, and sealing performance was impaired.

The lip seal of the present invention has been made in view of the above circumstances, and it is an object of the present invention to prevent the rubber lip member from deteriorating due to heat conduction from the PTFE lip member and preventing the sealing performance from being deteriorated due to the deterioration. It was done.

[0007]

In order to solve the above problems, the present invention provides a rubber lip member on a sealed space side and a PTFE lip member on a non-sealed space side on an inner periphery of a metal case. The lip members are integrally held, and the inner diameter ends of both lip members are in airtight sliding contact with the outer peripheral surface of the shaft, and the inner diameter end of the PTFE lip member supports the waist near the inner diameter end of the rubber lip member from the inner diameter side. A lip seal having a required number of recesses on one of an inner peripheral surface of a waist portion of the rubber lip member and an outer peripheral surface of an inner diameter end portion of the PTFE lip member. It is.

[0008]

According to the above construction, the contact area between the inner peripheral surface of the waist portion of the rubber lip member and the outer peripheral surface of the inner diameter end of the PTFE lip member is reduced by providing the concave portion, and the contact area is formed in the concave portion. Since the gap acts as an insulating portion against heat, short-circuited heat conduction from the inner diameter end of the PTFE lip member to the inner diameter end of the rubber lip member via the waist portion can be suppressed. .

[0009]

1 and 2 show a lip seal according to the present invention.
This will be described with reference to the embodiment shown in FIG. In the illustrated embodiment, the same parts as those in the conventional structure of FIG. 3 described above are denoted by the same reference numerals, and the description thereof will be omitted.

First, a first embodiment shown in FIG.
A plurality of grooves 23 as recesses continuous in the circumferential direction are provided on the inner peripheral surface of the waist portion 22 of the rubber lip member 2 which is in contact with the outer peripheral surface of the inner diameter end 31 of the lip member 3.

In the above configuration, the cylindrical inner end 31 of the PTFE lip member 3 comes into sliding contact with the outer peripheral surface of the shaft 8 while receiving the pressure in the sealed space A via the waist portion 22 of the rubber lip member 2. However, the contact area between the inner peripheral surface of the waist portion 22 of the rubber lip member 2 and the outer peripheral surface of the inner diameter end portion 31 of the PTFE lip member 3 is equal to the groove width of the plurality of grooves 23. And the gap formed in each groove 23 acts as an insulating portion against the heat. Accordingly, short-circuit heat conduction from the contact portion between the inner diameter end 31 of the PTFE lip member 3 and the waist portion 22 to the inner diameter end 21 of the rubber lip member 2 is suppressed.

A second embodiment shown in FIG. 2 is a PTFE contacting the inner peripheral surface of the waist portion 22 of the rubber lip member 2.
By providing a plurality of grooves 33 as concave portions continuous in the circumferential direction on the outer peripheral surface of the inner diameter end portion 31 of the lip-making member 3, the same effect as in the first embodiment can be obtained.

The recess is not limited to the circumferentially continuous grooves 23 and 33 as in the above embodiment. For example, the recess may be discontinuous in the circumferential direction, may extend in the axial direction, or may have a dimple shape. Various modifications are possible, such as a number of recesses.

[0014]

As described above, according to the present invention, the contact area between the inner peripheral surface of the waist portion of the rubber lip member and the outer peripheral surface of the inner diameter end of the PTFE lip member is reduced by providing the concave portion. Since the gap formed in the recess acts as an insulating portion against heat, short-circuit heat conduction from the inner diameter end of the PTFE lip member to the inner diameter end of the rubber lip member via the waist portion is suppressed. Thus, it is possible to prevent deterioration of the inner diameter end portion of the rubber lip member due to the heat and maintain excellent sealing performance for a long period of time.

[Brief description of the drawings]

FIG. 1 is a half sectional view showing a first embodiment of the present invention.

FIG. 2 is a half sectional view showing a second embodiment of the present invention.

FIG. 3 is a half sectional view showing an example of a conventional structure.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 metal case 2 rubber lip member 3 PTFE lip member 8 shaft 21, 31 inner diameter end 22 waist 23, 33 groove (recess) A sealed space B anti-sealed space

Claims (1)

(57) [Scope of request for utility model registration] A lip member made of rubber on the sealed space side and a lip member made of PTFE on the side opposite to the sealed space are integrally held on the inner periphery of the metal case, and the inner diameter ends of both lip members are formed on the shaft. In the lip-type seal, which is in air-tight sliding contact with the outer peripheral surface and in which the inner diameter end of the PTFE lip member supports the waist near the inner diameter end of the rubber lip member from the inner diameter side, the rubber material is in contact with each other. A lip seal having a required number of recesses provided on one of an inner peripheral surface of a waist portion of a lip member and an outer peripheral surface of an inner diameter end of a PTFE lip member.