JPH0583543U - Lip seal - Google Patents

Abstract

(57) [Summary] [Object] To prevent the lip member 120 from slipping out toward the inner diameter side due to the pressure in the sealed space A, improve heat resistance and freon resistance, and maintain the sealing property for a long time. [Constitution] The lip member 120 is a main body 121 made of PTFE.
And a synthetic rubber thin film 122 attached to the back surface including the inner peripheral surface of the inner diameter portion 121a of the main body 121. The inner diameter flange 103 of the outer case 100 and the inner diameter flange 112 of the inner case 110 face each other. One of them is formed with a punched-out portion 104 that extends in a circumferential shape and projects toward the lip member 120.

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. 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. That is, when the PTFE lip member 4 receives a high pressure in the sealed space A via the rubber lip member 2, the PTFE lip member 4 is largely bent and deformed toward the inner diameter side, and as shown by an arrow F in the figure. Since the inner diameter 2a of the rubber lip member 2 is crouched as shown by the broken line in the figure, the sliding area with the shaft 8 increases and the friction heat rises abnormally. It becomes.

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, attaches importance to oil resistance and wear resistance, the rubber is not heated under high heat conditions due to high pressure. It was observed that the elasticity deteriorated and leaks due to cracks and abnormal wear occurred.

Therefore, in order to improve the heat resistance, it is desirable to use fluorine rubber as the material of the rubber-made lip member 2. However, fluororubber has a high permeability to Freon, which is a refrigerant in the sealed space A. Since it is high, a large amount of freon easily penetrates into the rubber, and when the ambient temperature rises while the freon penetrates, the saturated vapor pressure of freon in the rubber atmosphere increases and cracks due to foaming occur in the rubber lip member 2. In practice, fluororubber could not be used because it would occur. Moreover, the sliding load of the inner diameter portion 2a of the rubber-made lip member 2 increases as the PTFE lip member 4 slips out toward the inner diameter side due to the high pressure in the sealed space A. The problem still remained.

The lip-type seal of the present invention has been made in view of the above points, and its purpose is to prevent the lip member from coming off to the inner diameter side due to the pressure of the sealed space, and to improve heat resistance and heat resistance. It is to improve the freon resistance and maintain the sealing property for a long time.

[0007]

[Means for Solving the Problems]

 In order to solve the above-mentioned problems, the present invention provides a shaft in a facing gap between an inner diameter flange portion of an outer case and an inner diameter flange of an inner case fitted to an inner circumference of an outer diameter tubular portion of the outer case. In a lip-type seal in which an inner diameter portion slidingly contacting the outer peripheral surface of the lip member sandwiches an outer diameter portion of a lip member that extends toward the sealed space side, the lip member includes a PTFE main body and an inner peripheral surface of the inner diameter portion of the main body. A synthetic rubber thin film adhered to the back surface of the inner diameter flange, and a punched-out portion extending in a circumferential shape protruding toward the lip member is formed on one of the facing portions of the inner diameter flanges. It is configured as follows.

[0008]

[Action]

 According to the above configuration, the PTFE main body of the lip member that is in contact with the sealed space has a low permeability of Freon, while the synthetic rubber thin film on the inner peripheral surface of the inner diameter of the main body is attached to the outer peripheral surface of the shaft by its elasticity. It is a close contact, and the end face exposed from the inner diameter of the tip of the main body only slightly contacts the sealed space, so that the permeation of Freon in the sealed space is suppressed. Further, the PTFE main body of the lip member has higher rigidity than the elastomer, and moreover, the lip member is attached to one of the inner case inner flange portion and the inner case inner flange portion which sandwich the outer diameter portion of the lip member. A protruding part that protrudes to the side is formed, and this protruding part presses the outer diameter of the lip member so as to press it to fix the lip member in a completely immovable state, so that even if the sealed space becomes high pressure, The member does not move so as to slip out toward the inner diameter side, and the load on the sliding surface made of the synthetic rubber thin film on the inner diameter portion of the lip member with respect to the shaft 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 for a compressor for a cooler. 100 is a metal outer case having an L-shaped section, and 110 is a metal inner case having an L-shaped section. , 120 are lip members whose inner diameter portion 120a is bent and extends toward the sealed space A side. The outer diameter tubular portion 111 of the inner case 110 is fitted to the inner circumference of the outer diameter tubular portion 101 of the outer case 100, and is fixed by the caulking portion 102. The inner case flanges 103 and 112 of the outer case 100 and the inner case 110 are axially opposed to each other, and the outer diameter portion 120b of the lip member 120 is sandwiched between the inner diameter flanges 103 and 112.

The lip member 120 has a main body 121 made of PTFE, which has higher rigidity than an elastomer such as synthetic rubber and hardly penetrates freon, and an adhesive on the entire back surface including the inner peripheral surface of the inner diameter portion 121 a of the main body 121 made of PTFE. The thin film 122 made of fluororubber is attached. Specifically, for example, the thickness of the PTFE main body 121 is about 1.0 mm, while the thickness of the fluororubber thin film 122 is 0.1 mm to 0.5 mm.

The inner diameter flange 103 of the outer case 100, which is in pressure contact with the back surface of the outer diameter portion 120 b of the lip member 120, extends in a circumferential shape that faces the inner diameter flange 112 of the inner case 110 and projects toward the lip member 120. The embossed portion 104 is formed. The punched-out portion 104 partially largely compresses and cuts into the fluororubber thin film 122 in the outer diameter portion 120b of the lip member 120.

The lip-type seal having the above-described structure is tightly fitted to the mounting portion formed in a stepped manner in the shaft hole of the housing 10 through the O-ring 20, fixed by the snap ring 30, and the inner diameter portion of the lip member 120. When the inner peripheral surface of 120a, that is, the inner diameter portion 122a of the fluororubber thin film 122 is in airtight sliding contact with the outer peripheral surface of the shaft 40, the refrigerant and the refrigerating machine oil in the sealed space A are prevented from leaking to the atmosphere in the anti-sealed space B. It will prevent. Since the O-ring 20 that seals between the housing 10 and the outer case 100 does not generate frictional heat unlike the moving part, it does not need to have such high heat resistance, and therefore the heat resistance is high. Nitrile rubber, which has a low but low freon permeability, is used.

Although the PTFE main body 121 has high heat resistance and does not allow the penetration of freon, the fluororubber thin film 122 has a tip surface 122b of its inner diameter 122a exposed from the tip inner diameter of the PTFE main body 121 to the sealed space A. Therefore, Freon in the sealed space A penetrates from the tip surface 122b. However, according to the structure of the present embodiment, the thickness of the fluororubber thin film 122, that is, the width of exposure to the sealed space A is extremely small at 0.1 mm to 0.5 mm, so the amount of permeation of freon is suppressed to a very small amount. Be done. Also, because of its thin wall, even if the permeated freon vaporizes at high temperature or low pressure, the vaporized freon is easily 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 a foaming phenomenon due to the penetration, even though the fluororubber that allows the freon to easily penetrate is used.

Since the PTFE main body 121 has a higher Young's modulus than the fluororubber thin film 122, the diameter reduction deformation amount due to the pressure in the sealed space A is small. Therefore, even if the sealed space A has a high pressure, an increase in the contact width between the inner diameter portion 122a of the fluororubber thin film 122 of the lip member 120 and the outer peripheral surface of the shaft 40 and an accompanying increase in the amount of sliding heat generation are suppressed. Be done. On the contrary, since the body 121 has a high Young's modulus, the initial tightening force, that is, the tightening force on the shaft 40 becomes large. Therefore, in order to reduce the sliding load due to such a tightening force, at least the body 121. The inner diameter portion 121a of the above has a thin structure with a thickness of about 1.0 mm. It should be noted that this wall thickness may be set appropriately in consideration of the usage conditions, such as the pressure in the sealed space A.

The inner diameter flange 103 of the outer case 100 has a function of backing up the outer diameter portion 120b of the lip member 120 from the side of the anti-sealing space B, and restricting the deformation of the lip member 120 due to the pressure of the sealing space A. The airtightness between the outer case 100 and the lip member 120 is maintained by being pressed against the outer diameter portion 122c of the fluororubber thin film 122, and the punching portion 104 formed on the inner diameter flange 103 of the outer case 100 is At the outer diameter portion 120b of the lip member 120, the outer diameter portion 120b of the lip member 120 is firmly clamped between the outer diameter portion 120b of the lip member 120 and the fluororubber thin film 122 on the back surface. ing. Therefore, the airtightness between the outer case 100 and the lip member 120 is very good, and the lip member 120 does not move to the inner diameter side due to the pressure in the sealed space A. The increase in the contact width between the inner diameter portion 122a of the fluororubber thin film 122 of 120 and the outer peripheral surface of the shaft 40 and the accompanying increase in the amount of sliding heat generation are suppressed.

The present invention is not limited to the structure of the illustrated embodiment. For example, the fluorine rubber thin film 122 is only covered on the inner peripheral surface of the inner diameter portion 121 a of the PTFE main body 121. It may be worn as a structure. Further, instead of the embossed portion 104, an embossed portion facing the inner diameter flange 103 of the outer case 100 may be formed on the inner diameter flange 112 of the inner sleeve 110.

[0017]

[Effect of the device]

 As described above, according to the present invention, first, the freon to be sealed is less likely to penetrate into the lip member. Also, crimp the punched part formed on one of the inner diameter flange of the outer case and the inner diameter flange of the inner case, which sandwich the outer diameter part of the lip member, so as to bite into the outer diameter part of the lip member. Since the lip member is fixed so that it does not move completely, the lip member does not move toward the inner diameter side even if the sealed space is at a high pressure, and is made of a synthetic rubber thin film on the inner diameter portion of the lip member relative to the shaft. Since the load on the sliding surface does not increase, sliding heat generation is suppressed and the heat resistance of the lip member can be improved. Therefore, it is possible to prevent the rapid vaporization of freon that has penetrated into the synthetic rubber thin film on the inner peripheral surface of the lip member and the foaming phenomenon that accompanies this.

[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]

 100 Outer Case 103, 112 Inner Diameter Flange 104 Stamping Part 110 Inner Case 120 Lip Member 121 PTFE Main Body 122 Fluoro Rubber Thin Film (Synthetic Rubber Thin Film) A Sealed Space B Anti-sealed Space

Claims (1)

[Scope of utility model registration request] 1. An inner diameter portion slidably contacting an outer peripheral surface of a shaft in a facing gap between an inner diameter flange portion of an outer case and an inner diameter flange of an inner case fitted to an inner circumference of an outer diameter cylindrical portion of the outer case. In a lip-type seal in which an outer diameter portion of a lip member that bends and extends to the sealed space side is sandwiched, the lip member is attached to the PTFE main body and the back surface including the inner peripheral surface of the inner diameter portion of the PTFE main body. A synthetic rubber thin film formed on the inner peripheral surface of the inner peripheral surface of the inner peripheral surface of the inner peripheral surface of the inner peripheral surface of the inner peripheral surface of the inner peripheral surface of the inner peripheral surface of the inner peripheral surface of the inner peripheral surface of the inner peripheral surface of the inner peripheral surface of the inner peripheral surface of the inner peripheral surface. Mold seal.