JPH0448365Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an improvement of a lip-type seal for sealing the rotating shaft of a machine body such as a compressor for a car air conditioner.

[Prior Art] Conventionally, in lip-type seals for car air conditioner compressors, etc., as shown in FIG.
When sealing the rotating shaft 3 inserted therein, the small diameter part 2a and the large diameter part 2b in the seal box 2 are sealed.
A lip seal 6 made of synthetic resin, such as PTFE, whose outer circumferential portion 6a is sandwiched between an outer casing 4 and an inner casing 5, and an inner diameter wall made of
is inserted in the axial direction from the sealing liquid W side, which is the large diameter part 2b side in the seal box 2, and abuts against the stepped surface 2c between the small diameter part 2a and the large diameter part 2b in the seal box 2. Some have a configuration in which the lip portion 61 is slid around the circumference of the rotating shaft 3 and sealed by fixing and assembling the rotary shaft 3.

[Problems to be solved by the invention] However, in the lip type seal of this conventional structure, since the seal of the sliding part to the rotating shaft 3 is only the resin lip 61, when the sealing liquid pressure increases, However, there were problems such as liquid leakage from the sliding part with the rotating shaft 3, instability in particular due to pulsation, and poor sealing performance.

[Purpose of the invention] The present invention was made under the above circumstances, and its purpose is to provide a lip-type seal that can improve sealing performance.

[Means for solving the problems] In order to solve the above problems, the present invention has the following features:
In a lip type seal formed by fixing a lip seal made of synthetic resin whose outer periphery is sandwiched between an outer casing and an inner casing to the inner diameter wall of a seal box of a housing into which a rotating shaft is inserted to seal the shaft, the lip seal is wetted with liquid. A floating ring whose inner circumferential surface is curved to correspond to the lip of the lip seal is disposed on the side, and the inner circumferential surface of the floating ring is closely opposed to the lip of the lip seal.

[Function] That is, in the present invention, with the above structure, the floating ring is disposed on the liquid contact side of the lip seal, so that the sealing liquid pressure acting on the outer circumferential surface of the lip of the lip seal is floating. When the pressure is reduced by the ring and the sealing liquid pressure becomes a reverse pressure state lower than the atmospheric pressure, the inner circumferential surface of the floating ring, which is closely opposed to the outer circumferential surface of the lip portion, absorbs the lip from the rotating shaft. This prevents the parts from lifting up.
It becomes possible to obtain stable sealing performance against pulsation.

[Example] The present invention will be described below with reference to an example shown in FIG. In the illustrated embodiment of the present invention, the same reference numerals are used for the parts having the same structure as those of the conventional lip type seal shown in FIG. 3, and the explanation thereof will be omitted.

That is, in the present invention, as shown in FIG. 1, a floating ring 7 made of carbon or synthetic resin is disposed on the sealing liquid W side, which is the wetted side of the lip seal 6. It is configured to hold the outer circumference of the lip part 61, and when the sealing liquid pressure becomes high, the liquid pressure acting on the outer circumferential surface of the lip part 61 is reduced, and the liquid pressure is lower than atmospheric pressure. When the reverse pressure becomes low, the liquid pressure acting on the outer circumferential surface of the lip portion 61 is suppressed from decreasing, and the lip portion 61 is prevented from being lifted from the outer circumferential surface of the rotating shaft 3 due to the pressure difference between the lip portion 61 and the atmospheric pressure. ,
It is restrained by the inner circumferential surface of the floating ring 7 which is curved to correspond to the lip portion 61 and is closely opposed to the lip portion 61.

By the way, according to the above-mentioned lip seal 6 according to the present invention, for example, the sealing liquid is turbine oil, the pressure is 2 Kg/cm ² G, the rotation speed is 2000 rpm, and the cumulative amount of oil leakage g over a specific period of time Hr is measured. As a result, as shown in FIG. 2, the lip seal of the present invention (plot: □) had almost no sudden leakage compared to the conventional lip seal (plot: ◯).

It should be noted that the present invention is not limited to the above-described embodiments, and it goes without saying that various modifications can be made without departing from the gist of the present invention.

[Effect of the invention] As is clear from the above explanation, according to the invention, when the sealing liquid pressure is high and positive, the sealing liquid pressure acting on the outer peripheral surface of the lip portion is reduced by the floating ring. Furthermore, when the sealing liquid pressure is lower than the atmospheric pressure, the inner circumferential surface of the floating ring that closely opposes the outer circumferential surface of the lip prevents the lip from lifting up from the rotating shaft, thereby preventing pulsation. However, it has an excellent effect in that stable sealing performance can be obtained.

[Brief explanation of drawings]

Fig. 1 is a schematic longitudinal sectional side view of the main parts showing an embodiment of the lip seal according to the present invention, and Fig. 2 compares the measurement results of the cumulative oil leakage amount over time of the lip seal of the present invention with that of a conventional product. Explanatory diagram shown as 3rd
The figure is a schematic longitudinal sectional side view of the main parts of a conventional lip-type seal. 1...Housing, 2...Seal box, 3
... Rotating shaft, 4... Outer casing, 5... Inner casing, 6... Lip seal, 61... Lip portion, 7... Floating ring, W... Sealing liquid.

Claims (1)

[Scope of utility model registration request] A lip seal made of synthetic resin whose outer periphery is sandwiched between an outer casing and an inner casing and whose inner periphery lip part that makes sliding contact with the rotating shaft is curved and protrudes toward the sealing fluid side, on the inner diameter wall of the seal box of the housing into which the rotating shaft is inserted. In a lip-type seal with a lip fixed thereon, a floating ring whose inner circumferential surface is formed into a curved shape corresponding to the lip part is disposed on the liquid contact side of the lip seal, and the inner circumferential surface of the floating ring is connected to the outer circumferential surface of the lip part. A lip-type seal characterized by closely facing each other.