JPH0581566U - Lip seal - Google Patents

Abstract

(57) [Abstract] [Purpose] To improve the heat resistance and freon resistance of the elastomer lip member 110 so that it can be used as a shaft sealing device for a high pressure compressor. [Structure] An elastomer lip member 110 is provided on an inner circumference of a metal case 100, and the elastomer lip member 110 is provided.
First PT facing the sealed space A, which is spaced apart from the front side of the
The FE lip member 120 and the second PT on the atmosphere B side that is arranged along the back surface of the elastomer lip member 110.
The FE lip member 130 is integrally held.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 TECHNICAL FIELD The present invention relates to a lip-type seal, in which freon, which is a refrigerant of a refrigerator, is sealed.

[0002]

[Prior Art]

 2. Description of the Related Art Conventionally, as a shaft sealing device used in, for example, a car cooler compressor, there is a lip type seal as shown in FIG. This lip-type seal has a base portion having an outer diameter on the inner side of the sealed space A on the inner periphery of the metal case 1 which is tightly fitted and fixed to the mounting portion 6a formed in the shaft hole of the housing 6 via the O-ring 7. An elastomer lip member 2 reinforced by a metal ring 3, a PTFE lip member 4 having heat resistance on the atmosphere B side, and a metal back-up ring 5 supporting the PTFE lip member 4 from its anti-seal space B side. , The respective outer diameter portions are held in close contact with each other, and the inner diameter portion 2a of the 5 elastomer lip member 2 makes airtight sliding contact with the outer peripheral surface of the shaft 8, and the refrigerant and the refrigeration oil in the sealed space A leak into the atmosphere B. To prevent the

[0003]

[Problems to be solved by the device]

In the lip type seal having the above-described conventional structure, the elastomer lip member 2 receives the high pressure in the sealed space A and is bent and deformed to the inner diameter side, and the inner diameter portion 2a is tilted as shown by the broken line in the figure to slide with the shaft 8. because results in an increase in the increase thus sliding load of the dynamic range, the pressure of the blame tax sealed space a is Tsu Naka available only in 1kg / cm ² ~4kg / cm ² about conditions. That is, when used under a high pressure condition such that the pressure in the sealed space A exceeds 4 kg / cm ² , the inner diameter portion 2a of the elastomer lip member 2 is deteriorated due to the increase in frictional heat, and cracks and leakage due to abnormal wear occur in a short period of time. Because. However, there are some cooler compressors in recent years that greatly exceed the above-mentioned operating limit pressure, for example, those that increase up to about 20 kg / cm ² , and as a shaft seal device for such a high-pressure compressor. Inevitably, they have no choice but to use expensive mechanical seals.

Further, in order to improve the heat resistance, it is most preferable to use fluororubber for the elastomer lip member 2. However, since fluororubber has high permeability of Freon, which is a refrigerant liquid in the sealed space A, If a large amount of freon permeates and swells, and the ambient temperature rises or the pressure drops in this state, the permeated freon vaporizes, causing a foaming phenomenon in the elastomer lip member 2, which may cause cracking. Therefore, after all, fluororubber cannot be used.

The lip-type seal of the present invention has been made in view of the above points, and an object thereof is to be usable as a shaft sealing device for a high-pressure compressor.

[0006]

[Means for Solving the Problems]

 In order to solve the above-mentioned problems, the lip-type seal according to the present invention integrally holds, on the inner circumference of a metal case, a plurality of lip members whose inner diameter portions in sliding contact with the outer circumferential surface of the shaft protrude toward the sealed space side. These lip members are, respectively, a fluororubber lip member, a first PTFE lip member that is spaced apart from the front face side of the fluororubber lip member and faces the sealed space, and a back face of the fluororubber lip member. The second PTFE lip member on the atmosphere side, which is arranged in the same manner, is used.

[0007]

[Action]

 According to the above configuration, the pressure in the sealed space is blocked by the first PTFE lip member that is spaced apart on the front side of the fluororubber lip member, so the pressure acting on the fluororubber lip member from the front is reduced. To be done. Further, since the freon leaking from the sealed space to the back side of the first PTFE lip member is vaporized by the above-mentioned decompression, the swelling of the fluororubber lip member due to the freon is slight. The fluororubber lip member slides on the shaft without liquid lubrication, but it has good heat resistance due to its material, and the second PTFE backs up this fluororubber lip member from the atmosphere side. This reduces the sliding load on the fluororubber lip member without lubrication.

[0008]

【Example】

 FIG. 1 shows an embodiment of a lip type seal of the present invention used as a shaft seal device for a compressor for a cooler. It is made of a metal case 100 made of steel such as SPCC and an FKM (fluorine rubber) excellent in heat resistance. Fluoro rubber lip member 110, first PTFE lip member 120 arranged on the front side of fluoro rubber lip member 110, and second PT FE lip arranged on the back side of fluoro rubber lip member 110. And a member 130.

Of the lip members 110, 120, 130, the inner diameter portion 111 of the fluororubber lip member 110 projects toward the front side (sealed space A side), and a sliding edge 111 a is formed on the inner diameter at the tip thereof. The outer diameter base 113 in which the reinforcing ring 112 having an L-shaped cross section is embedded is formed with a spacer portion 113a protruding toward the front side. The first PTFE lip member 120 has a sheet-like shape with a substantially square cross section in which the inner diameter portion 121 is curved and protrudes to the front side, and the second PTFE lip member 130 is made of a fluororubber lid. The inner diameter portion 131 protrudes along the back surface of the push member 110 while curving to the front side, and like the first PTFE lip member 120, has a sheet shape with a substantially "C" cross section.

A metal pressing ring 140 is arranged on the front surface of the outer diameter portion 122 of the first PTFE lip member 120, and the back surface of the outer diameter portion 122 and the spacer portion 113 a of the fluororubber lip member 110 are connected to each other. The first metal backup plate 150 having the elastomer film 151 adhered to the front surface is disposed between the two, and the second metal backup plate 150 is disposed on the back surface of the outer diameter portion 132 of the second PTFE lip member 130. A metal backup plate 160 is arranged.

The cylindrical metal case 100 comprehensively holds the above-mentioned members on its inner circumference. That is, in each of the above members, with the metal pressing ring 140 as the frontmost side, the first PTFE lip member 120, the first metal backup plate 150, the fluororubber lip member 110, the second PTFE lip member 130, and the second PTFE lip member 130 The metal back-up plates 160 are sequentially arranged, and are sandwiched between the annular O-ring mounting portion 101 that is bent toward the inner diameter side at one end of the metal case 100 and the crimping portion 102 formed at the other end. .. In this state, the inner diameter portion 111 of the fluororubber lip member 110 and the inner diameter portion 121 of the first PTFE lip member 120 on the front side of the fluororubber lip member 110 are separated from each other by the spacer portion 113a having the outer diameter of the fluororubber lip member 110. It is separated. In addition, an annular protrusion 113b is formed on the outer periphery of the base 113 of the fluororubber lip member 110 including the spacer 113a, and a part of the elastomer is protruded, and the protrusion 113b is a metal case. It adheres to the inner peripheral surface of 100 in a compressed state to maintain airtightness with the metal case 100.

The lip-type seal having the above-described structure is press-fitted to the mounting portion 11 formed in steps in the shaft hole of the housing 10 via the O-ring 20 mounted to the O-ring mounting portion 101 of the metal case 100. The sliding edge 111a of the fluoro rubber lip member 110 and the inner peripheral surfaces of the inner diameter portions 121 and 131 of the PTFE lip members 120 and 130 are fixed to the inner circumference of the shaft hole. The refrigerant and refrigerating machine oil in the sealed space A are prevented from leaking into the atmosphere B by making sliding contact with the outer peripheral surface of the shaft 40 inserted into the air.

Here, the first PTFE lip member 120 facing the sealed space A shuts off the high pressure of the sealed space A to the inner diameter portion 111 of the fluororubber lip member 110. That is, since the first PTFE lip member 120 is poor in elasticity, it cannot be expected that the inner peripheral surface of the inner diameter portion 121 of the first PTFE lip member 120 is sufficiently brought into close contact with the outer peripheral surface of the shaft 40 to exert a complete sealing function, but the sealed space is small. The leak liquid slightly passing through the first PTFE lip member 120 from A is sufficiently decompressed, and therefore the sealed space A is formed in the inner diameter portion 111 of the fluororubber lip member 110 which is spaced apart from the back surface thereof. High pressure of does not work. The first PTFE lip member 120, which directly receives the high pressure of the sealed space A on the front side, is supported from the back side by the first metal backup plate 150, and its deformation due to pressure is restricted.

Freon in the leaked liquid that has leaked from the sealed space A to the back side of the first PTFE lip member 120 is vaporized by the above-mentioned depressurization, so that the sliding formed on the inner diameter portion 111 of the fluororubber lip member 110. The edge 111a comes into sliding contact with the outer peripheral surface of the shaft 40 in a state where it is hardly liquid-lubricated, and the amount of heat generated by sliding increases, but since the lip member 110 made of fluorine rubber is excellent in heat resistance, it is sufficient. Has excellent resistance. Further, generally, this fluororubber has a problem that it is easily swelled by the Freon liquid, but as described above, it leaks from the first PTFE lip member 120 to the front space of the fluororubber lip member 110. Since Freon is in a vaporized state, such swelling and foaming phenomenon in the fluororubber are prevented. If it is expected that the sliding conditions will not be able to withstand the heat even with fluororubber, heat-resistant grease should be filled between the first PTFE E lip member 120 and the fluororubber lip member 110. It is effective to set.

When the vaporized Freon fills the space in front of the fluororubber lip member 110, the pressure of the freon gas acts on the inner diameter portion 111 of the fluororubber lip member 110 as a load in the radial contraction direction. Since the back surface of the member 110 including the inner peripheral surface of the inner diameter portion 111 is backed up by the second PTFE lip member 130 from the atmosphere B side, the fluororubber lip member 110 with respect to the outer peripheral surface of the shaft 40 is backed up. The sliding width of the sliding edge 111a does not become excessively large, and the increase in heat generation due to unlubricated sliding can be suppressed. Further, at this time, the deformation of the second PTFE lip member 130 itself, which receives the pressure of the Freon gas via the fluororubber lip member 110, is restricted by the second backup plate 160 which supports the back surface thereof. ..

It should be noted that the present invention is not limited to the structure of the illustrated embodiment, and for example, the reinforcing ring 112 embedded in the fluoro rubber lip member 110 and the first metal back-up plate 150 are integrated. Alternatively, the inner diameter of the second metal backup plate 160 may be provided with a dust lip member facing the atmosphere B side, and other various shapes may be changed.

[0017]

[Effect of the device]

 As described above, according to the lip-type seal of the present invention, (1) the fluororubber lip member, which is the main seal, does not contact the liquid freon in the sealed space, so that it does not swell due to the penetration of freon, and Therefore, the fluororubber lip member is not cracked due to the foaming phenomenon of the elastomer due to the vaporization of the infiltrated freon. (2) As described in (2) above, the fluororubber lip member does not swell or foam due to the penetration of freon. Using, it is possible to obtain sufficient resistance to frictional heat during sliding. (3) The high pressure of the sealed space does not directly act on the front surface of the fluororubber lip member, and as described in (2) above, the heat resistance of the fluororubber lip member can be improved, so it is not excessive. It is possible to prevent cracks and abnormal wear of the inner diameter of the fluororubber lip member due to various sliding loads (heat generation).

[Brief description of drawings]

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

FIG. 2 is a half-cut sectional view showing an example of a conventional structure.

[Explanation of symbols]

 10 Housing 20 O-ring 40 Shaft 100 Metal Case 110 Fluororubber Lip Member 111, 121, 131 Inner Diameter Part 111a Sliding Edge 113a Spacer Part 120 First PTFE Lip Member 130 Second PTFE Lip Member 140 Metal Pressing Ring 150th First metal backup plate 160 Second metal backup plate A Sealed space B Atmosphere

Claims (1)

[Scope of utility model registration request] 1. A plurality of lip members, each having an inner diameter portion slidably contacting the outer peripheral surface of the shaft and protruding toward the sealed space, are integrally held on the inner circumference of the metal case, and each of these lip members is made of a fluororubber lip member. And the first P facing the sealed space, which is spaced apart from the front side of the fluororubber lip member.
A lip type seal comprising a TFE lip member and a second PTFE lip member on the atmosphere side arranged along the back surface of the fluororubber lip member.