JPH0557520U - Lip seal - Google Patents

Abstract

(57) [Summary] [Purpose] To improve the heat resistance and pressure resistance of the lip member 14 and to maintain the sealing property for a long time. [Structure] The lip member 14 is made of a resin material having higher rigidity and lower penetrability of freon than an elastomer.
41 and a synthetic rubber thin film 142 adhered to the inner peripheral surface of the inner diameter portion 141a of the main body 141, and the back surface of the lip member 14 is supported by a support ring 15 made of a resin material having higher rigidity than an elastomer. The inner diameter of the support ring 15 has a lip portion 15a that is in sliding contact with the outer peripheral surface of the shaft 18 and is in contact with the inner diameter portion of the lip member 14.

Description

[Detailed description of the device]

[0001]

[Industrial application]

 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. A rubber-made lip member 2 made of nitryl rubber (NBR) reinforced with a metal ring 3, a PTFE lip member 4 having heat resistance on the anti-seal space (atmosphere) B side, and the PTFE lip member 4 are provided. The metal backup ring 5 supported from the anti-seal space B side is held in a state where the outer diameter portions thereof are in close contact with each other, and the inner diameter portions 2a, 4a of the lip members 2, 4 become the outer peripheral surface of the shaft 8. Airtight sliding contact is made to prevent the refrigerant and refrigerating machine oil in the sealed space A from leaking to the anti-sealed space B, that is, the atmosphere.

[0003]

[Problems to be solved by the device]

In the above lip-type seal, the pressure in the sealed space A during normal operation is about 1 kg / cm ² to 4 kg / cm ² , and it is used for a compressor having relatively loose operating conditions represented by a so-called swash plate type. There were many. However, recent cooler compressors tend to increase the temperature of the sealed space A (compression chamber) due to downsizing and speeding up, and the newly developed variable displacement compressor is Since the pressure in the space A (compression chamber) increases, the amount of heat generated by the sliding of the rubber-made lip member 2 and the shaft 8 on the sealed space A side tends to increase accordingly.

However, according to the above-mentioned conventional lip-type seal, since the nitrile rubber, which is the material of the rubber-made lip member 2, emphasizes oil resistance, wear resistance, and freon resistance, high temperature atmosphere conditions and high speed Under high heat generation conditions due to sliding, rubber elasticity deteriorated, and cracks and leakage due to abnormal wear were found to occur. Further, since the inner diameter portion 2a of the rubber lip member 2 is not backed up by the PTFE lip member 4, when the sealed space A has a high pressure, the inner diameter portion 2a of the rubber lip member 2 with respect to the shaft 8 is The sliding load became extremely large, and the above cracks, wear, and seizure were likely to occur.

By the way, in order to improve the heat resistance, it is desirable to use fluorine rubber as the material of the rubber-made lip member 2, but an increase in sliding load under high pressure conditions cannot be avoided. Moreover, since fluororubber has a high permeability of Freon, which is a refrigerant in the sealed space A, a large amount of Freon easily penetrates into the rubber, and if the ambient temperature rises while Freon has permeated, the Freon in the rubber atmosphere becomes Since the saturated vapor pressure becomes high and the rubber-made lip member 2 is cracked due to foaming, the fluororubber cannot be actually used.

The lip-type seal of the present invention has been made in view of the above points, and an object thereof is to improve the heat resistance and pressure resistance of the lip member and maintain the sealing property for a long period of time. It is in.

[0007]

[Means for Solving the Problems]

 In order to solve the above problems, a lip-type seal according to the present invention is a lip in which an inner peripheral portion of a metal case, which has an inner diameter portion slidably contacting an outer peripheral surface of a shaft, is bent and extends toward a sealed space, and is integrally held. In the mold seal, the lip member consists of a liquid-side body made of resin, which is more rigid than elastomer and has low penetrability of freon, and a synthetic rubber thin film adhered to the inner surface of the inner diameter of this body. The back surface including the inner diameter of the lip member is supported by a support ring made of a resin material, which has a lip portion that is in sliding contact with the outer peripheral surface of the shaft on the inner diameter and has higher rigidity than elastomer. ..

[0008]

With the above structure, the liquid-contacting side body of the lip member that is in contact with the sealed space has low permeability to freon, while the synthetic rubber thin film adhered to the inner peripheral surface of the inner diameter of the body is The elasticity ensures close contact with the outer peripheral surface of the shaft, and the end surface exposed from the inner diameter of the tip of the main body only slightly contacts the sealed space, so that penetration of freon in the sealed space is suppressed. The body of the lip member on the liquid contact side is more rigid than the elastomer, and the back surface of the lip member except for the sliding surface with the shaft is supported by a support ring. Since it has a lip part that is almost in sliding contact with the surface and is made of a resin material that is more rigid than an elastomer, it has a large supporting force for the lip member, so that even if the sealed space is at high pressure, the inner diameter of the lip member with respect to the shaft The load on the sliding surface made of synthetic rubber thin film does not increase.

[0009]

【Example】

 FIG. 1 shows an embodiment of a lip-type seal of the present invention used as a shaft sealing device of a compressor for a cooler. Reference numeral 11 denotes a metal outer case having an L-shaped cross section, and 12 denotes an inner circumference of the outer case 11. It is a metal inner case with an L-shaped cross section that is fixed by crimping. The outer case 11 has a gasket portion 13a protruding annularly on the outer circumference of the outer diameter tubular portion 11a, and a dust lip extending from the inner diameter end portion of the inner diameter flange 11b to the anti-sealing space B, that is, the atmosphere side. A sealing member 13 made of nitrite rubber having an adhesive 13b is vulcanized and adhered.

Inner diameter flanges 11b and 12a of the outer case 11 and the inner case 12 are opposed to each other in the axial direction, and between the flanges 11b and 12a, a lip member whose inner diameter portion is bent and extends toward the sealed space A side. 14 and a support ring 15 on the side opposite to the sealed space B are sandwiched. Of these, the lip member 14 includes a liquid contact side body 141 made of a resin material such as PTFE that has higher rigidity than an elastomer such as synthetic rubber and hardly penetrates freon, and an inner peripheral surface of an inner diameter portion 141a of the body 141. It is composed of a fluororubber thin film 142 adhered to the entire back surface including an adhesive. Specifically, for example, the thickness of the liquid contact side body 141 is about 1.0 mm, while the thickness of the fluororubber thin film 142 is 0.1 mm to 0.5 mm.

The support ring 15 is made of a resin material such as PTFE having a sufficiently high rigidity as compared with an elastomer such as synthetic rubber, and has an inner diameter inclined toward the sealed space A side. A lip portion 15a is provided. The front surface 15b of the support ring 15 including the lip portion 15a has a gentle curved surface conforming to the shape of the lip member 14, and is in contact with the back surface of the lip member 14, that is, the back surface of the fluororubber thin film 142. The back surface 15c of the support ring 15 is a flat surface that is in close contact with the thin film portion 13c that is a part of the seal member 13 and is attached to the front surface of the inner diameter flange 11b of the outer case 11.

The lip-type seal having the above-mentioned structure is tightly fitted to the mounting portion 16 a formed in the shaft hole of the housing 16 at the gasket portion 13 a of the seal member 13, fixed by the snap ring 17 and at the same time, the lip member 14 Since the inner peripheral surface of the inner peripheral portion of the inner peripheral surface, that is, the inner peripheral portion 142a of the fluorine rubber thin film 142 is in airtight sliding contact with the outer peripheral surface of the shaft 18, the refrigerant and the refrigerating machine oil in the sealed space A are exposed to the atmosphere in the anti-sealed space B. It prevents it from leaking in.

The resin material (PTFE) that constitutes the liquid contact side body 141 has high heat resistance and does not penetrate freon, but the fluororubber thin film 142 has a tip surface 142 b of the inner diameter part 142 a of the body 141. Since it is exposed to the sealed space A from the inner diameter of the tip, Freon in the sealed space A permeates from the tip surface 142b. However, according to the configuration of the present embodiment, the thickness of the fluororubber thin film 132, that is, the width of exposure to the sealed space A is as small as 0.1 mm to 0.2 mm, so the permeation amount of freon can be suppressed to a very small amount. .. Further, due to its thin wall, even if the permeated freon vaporizes at high temperature or low pressure, the vaporized freon is released from the rubber surface, and the foaming phenomenon does not occur in the rubber atmosphere. Therefore, it is possible to prevent a large amount of freon from penetrating and the foaming phenomenon due to the penetration of freon, even though the fluorine rubber is used.

Since the liquid contact side body 141 is made of a resin material having a higher Young's modulus than the fluororubber thin film 142, the amount of contraction deformation due to the pressure in the sealed space A is small, and therefore the lip member 14 at high pressure is reduced. An increase in the amount of sliding heat generated due to an increase in the contact width with the outer peripheral surface of the shaft 18 is suppressed. On the contrary, since the main body 141 has a high Young's modulus, the initial tightening force, that is, the tightening force with respect to the shaft 18 becomes large. The inner diameter portion 141a of 141 has a thin structure with a thickness of about 1.0 mm. It should be noted that this wall thickness may be appropriately set in consideration of use conditions such as the pressure in the sealed space A.

Further, in the support ring 15 made of a resin material such as PTFE having a sufficiently high rigidity as compared with an elastomer such as synthetic rubber, the front surface 15b of the support ring 15 including the lip portion 15a having the inner diameter is a lip member. The rear surface of 14 is supported up to the vicinity of the inner diameter portion 142a which is a sliding surface with the shaft 18, and the lip portion 15a of the support ring 15 is formed so as to be substantially in sliding contact with the outer peripheral surface of the shaft 18. Therefore, the supporting force for the lip member 14 is large. That is, since the support ring 15 has an excellent supporting force for the lip member 14 in addition to the high rigidity of the liquid contact side body 141 of the lip member 14, even if the sealed space A has a high pressure, the shaft 18 It is possible to suppress the increase of the sliding load of the lip member 14 with respect to the minute.

When the inclination angle of the front surface 15b of the support ring 15 with respect to the plane orthogonal to the axis is increased, the total load applied to the lip member 14 is reduced, and the sliding surface pressure on the shaft 18 is reduced, so that the sealing performance is improved. If the inclination angle is decreased, the contact width between the lip member 14 and the shaft 18 becomes large when the pressure in the sealed space A rises, resulting in an increase in the amount of heat generation. Therefore, the inclination angle is 20 to 70 °. It is desirable to set the range to.

The seal portion 13 integrally vulcanized and bonded to the outer case 11 does not generate frictional heat unlike the sliding portion except the dust lip 13b, and the dust lip 13b is also sealed in the sealed space A. Since it does not receive the pressure of, the sliding load is small and it is not necessary to require such high heat resistance. Therefore, it is possible to use nitrile rubber with low heat resistance.

The present invention is not limited to the structure of the illustrated embodiment. For example, the fluorine rubber thin film 132 is attached only to the inner peripheral surface of the inner diameter portion 131a of the PTFE main body 13. It is also possible to have a structure. Further, the dust lip 13b is for preventing the intervention of foreign matter in the atmosphere, but the necessity thereof is determined by the environmental conditions of use.

[0019]

[Effect of the device]

 As described above, according to the present invention, the liquid contact side body of the lip member that contacts the sealed space is made of a highly rigid resin material, and the back surface of the lip member except the sliding surface with the shaft is supported by the support ring. Since this support ring has a lip part on its inner diameter that is almost in sliding contact with the outer peripheral surface of the shaft and is made of a resin material that is more rigid than an elastomer, it has a large supporting force for the lip member and, therefore, the sealed space has a high pressure. However, the sliding load of the lip member on the shaft does not increase, the pressure resistance and heat resistance are improved, and excellent sealing performance can be maintained for a long time.

[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]

 11 Outer Case (Metal Case) 12 Inner Case (Metal Case) 14 Lip Member 141 Liquid Contact Side Body 142 Fluorine Rubber Thin Film (Synthetic Rubber Thin Film) 15 Support Ring 15a Lip Part 18 Shaft A Sealed Space B Anti-sealed Space

Claims (1)

[Scope of utility model registration request] 1. A lip-type seal integrally holding, on an inner periphery of a metal case, a lip member whose inner diameter portion slidably contacting an outer peripheral surface of a shaft bends and extends toward a sealed space, wherein the lip member is more rigid than an elastomer. The main body is made of a resin material with high permeability and low freon permeability, and a synthetic rubber thin film adhered to the inner peripheral surface of the inner diameter of the main body. A lip-type seal characterized in that the back surface except for is supported by a support ring made of a resin material, which has a lip portion that is in sliding contact with the outer peripheral surface of the shaft on the inner diameter and has higher rigidity than an elastomer.