JPH0530637U - Temperature compensated oil seal - Google Patents

Abstract

(57) [Summary] [Purpose] Deformation of the rubber lip seal due to temperature rise and sealing pressure during operation can be suppressed to maintain stable sealing performance even when the temperature rises, and the amount of wear of the rubber lip portion. The present invention is to provide a temperature-compensated oil seal in which the heat resistance is reduced and the durability is improved by preventing thermal deterioration due to frictional heat generated by sliding contact between the rubber lip portion and the rotary shaft. [Constitution] The base (14) is sealed and fixed in the housing (4),
A rubber lip seal (5) having a cone-shaped lip portion (16) formed by bulging the tip portion (15) to the rotary shaft (3) so as to swell toward the high-pressure sealed side (A), At the tip of the non-sealing side (B) of the lip seal made of synthetic resin, the minimum inner diameter is set larger than the outer diameter of the rotating shaft, which is made of synthetic resin with a thermal expansion coefficient of 5 × 10 ^-5 / ° C or more. The ring-shaped reinforcing ring (8) is closely attached.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an oil seal equipped with a rubber lip seal used for an open type compressor such as a compressor for an air conditioner of an automobile. More specifically, it suppresses deformation of the rubber lip seal due to temperature rise during operation and sealing pressure. The present invention relates to a temperature-compensated oil seal that has improved durability by preventing thermal deterioration due to frictional heat.

[0002]

[Prior Art]

Conventionally, various oil seals provided with a rubber lip seal having excellent sealing performance and followability to shaft runout have been provided. When used in open type compressors such as automobile air-conditioning compressors, the oil seal is always exposed to the atmosphere of refrigerating machine oil and refrigerant, which has a maximum temperature of 150 ° C and a maximum pressure of 15 kg / cm ² , and has a rotating shaft. Friction heat is generated due to sliding contact with. Therefore, the lip part of the rubber lip seal during operation softens as the temperature of the sealing oil liquid rises and the temperature rises due to the frictional heat with the rotating shaft, and the lip pressure deforms due to the sealing pressure to make contact with the rotating shaft. The area increases. As a result, the amount of wear of the rubber lip increases, and a vicious cycle phenomenon occurs such that the temperature rises due to frictional heat, resulting in a significant loss of its durability.

Therefore, as disclosed in Japanese Utility Model Laid-Open No. 3-12666, a synthetic resin ring having a low friction coefficient so as to be in sliding contact with the rotating shaft on the tip side of the rubber lip seal and on the side opposite to the seal side. Now, a lip-type seal that is integrally baked is provided.

However, since the deformation of the tip of the rubber lip seal is suppressed when the synthetic resin ring is in sliding contact with the rotating shaft, this synthetic resin ring also rubs due to sliding contact with the rotating shaft. The problem of heat generation and thermal deterioration of the lip of the rubber lip seal remains unsolved.

[0005]

SUMMARY OF THE INVENTION In view of the above situation, the present invention is to solve the problem by suppressing the temperature rise during operation and the deformation of the rubber lip seal due to the sealing pressure, so that the temperature rises. The stable sealing performance can be maintained, the amount of wear of the rubber lip part is reduced, and the thermal deterioration due to frictional heat generated by the sliding contact between the rubber lip part and the rotary shaft is prevented to improve durability. The point is to provide a temperature-compensated oil seal.

[0006]

[Means for Solving the Problems]

In order to solve the above-mentioned problems, the present invention is a rubber lip in which a base is hermetically fixed in a housing, and a tip is swollen to a high-pressure sealed side so that the tip slides on a rotating shaft to form a cone-shaped lip. The rubber lip seal is provided with a seal and is formed of synthetic resin having a heat expansion coefficient of 5 × 10 ⁻⁵ / ° C. or more at the tip of the rubber seal on the non-sealing side. A temperature-compensated oil seal was constructed by closely adhering a ring-shaped reinforcing ring with a large inner diameter.

In addition, a rubber lip seal having a cone-shaped lip portion formed by hermetically fixing the base portion inside the housing and bulging toward the high-pressure sealing side so that the tip portion slides on the rotating shaft, and the inside of the housing. And has a cone-shaped lip portion that is located on the anti-sealing side of the rubber lip seal, seals and fixes the flange portion to the base portion, and extends radially inward of the lip portion from the flange portion. and a synthetic resin lip seal, said a counter-sealing side of the distal end portion of the rubber-made lip seal, the radially outer position of the ripple-flop portion of the synthetic resin lip seal, the coefficient of thermal expansion 5 × 10 ^{- A} temperature-compensated oil seal was constructed by closely adhering a ring-shaped reinforcing ring made of a synthetic resin with a heat resistance of ⁵ / ° C or higher, the minimum inner diameter of which is set larger than the outer diameter of the rotating shaft.

As a structure for mounting the reinforcing ring, a structure in which the reinforcing ring is attached in a close contact state in an annular groove formed at the tip of the rubber lip seal on the non-sealing side, or a reinforcing ring made of rubber is used. A structure is adopted in which the tip of the lip seal on the non-sealing side is baked and attached.

[0009]

[Action]

The temperature-compensated oil seal of the present invention having the above-mentioned contents is a rubber lip seal, particularly the lip portion at the tip of the rubber lip seal due to the temperature rise of the sealing oil liquid during operation and the temperature rise due to frictional heat with the rotating shaft. Is softened and the lip is deformed by the sealing pressure and excessively contacts the peripheral surface of the rotating shaft. Prevent it. That is, the sealing pressure acts in the direction of pressing the lip part against the peripheral surface of the rotating shaft, but the reinforcing ring made of synthetic resin having a heat expansion coefficient of 5 × 10 ^-5 / ℃ or more has an ambient temperature. Thermal expansion of about 0.5 to 1% of its diameter is performed at 100 to 150 ° C, and the expansion force acts outward in the radial direction to expand the lip portion, and the sealing pressure and the expansion force are balanced to make the rubber lid. The deformation of the seal is suppressed. Also, since the minimum inner diameter of the reinforcing ring is set larger than the outer diameter of the rotating shaft, the reinforcing ring does not slide on the rotating shaft to generate friction heat, and the contact area between the lip and the rotating shaft is small. Since the frictional heat does not rise excessively since it is maintained at a substantially constant level, thermal deterioration due to frictional heat at the lip can be suppressed.

[0010]

【Example】

 The present invention will be further described in detail with reference to the embodiments shown in the accompanying drawings.

FIG. 1 shows a typical embodiment of a temperature-compensated oil seal 1 of the present invention, which is installed between an opening of a casing 2 of a compressor main body and a rotary shaft 3 penetrating therethrough, and an oil One of the seals 1 is a high-pressure sealed side A for enclosing refrigerating machine oil, a refrigerant, etc., and the other is an anti-sealing side B.

In the oil seal 1 of the present invention, a rubber lip seal 5 and a synthetic resin lip seal 6 are hermetically attached to an inside of a housing 4 which is hermetically attached to a casing 2 by an annular support member 7, and a rubber lip seal is also attached. 5 has a structure in which a reinforcing ring 8 made of a synthetic resin having thermal expansion properties and heat resistance is attached in close contact with the tip portion of 5 on the side opposite to the hermetically sealed side. The details of each part will be described below.

The housing 4 is hermetically mounted in the opening of the casing 2 of the compressor main body, and has an outer annular wall in the radial direction on one axial side of the metal hollow ring body 9, that is, on the anti-sealing side B. 10 on the other side, that is, on the other side, that is, on the sealing side A, an inner annular wall 11 is extended inward in the radial direction, and an inner peripheral edge of the inner annular wall 11 is extended outward along the axial direction. In addition, an O-ring groove 12 that extends outward in the semi-radial direction and is open to the outside is formed, so that the inner wall of the hollow ring body 9 and the outer annular wall 10 and the inner annular wall 11 form an annular recess that opens inward. Location 13 is formed. In addition, the outer annular wall 10 has the rubber lip seal 5, the synthetic resin lip seal 6, and the annular support member 7 housed in the annular recess 13, and then the end of the hollow annular body 9 is radially inward. It is formed by caulking or notching at the end of the hollow ring 9 and bending inward in the radial direction.

The rubber lip seal 5 has a base portion 14 that is in close contact with the inner wall of the annular recess 13 and the inner annular wall 11, and extends radially inward from the base portion 14 and further bulges toward the sealing side A. It has a tip portion 15, and the tip of the tip portion 15 is a cone-shaped lip portion 16 that is in sliding contact with the rotating shaft 3. A metallic core ring 17 is embedded in the base 14 for reinforcement. An annular groove 18 is formed at the intermediate position of the inner peripheral surface of the tip portion 15 on the side opposite to the hermetically sealed side B, and a reinforcing ring 8 is attached to the annular groove 18 in a close contact state. ing.

The synthetic resin lip seal 6 is formed of synthetic resin such as ethylene tetrafluoride resin, and has a flange portion 19 that can be in close contact with the base portion 14 of the rubber lip seal 5, and a rotary shaft from the flange portion 19. 3 has a cone-shaped lip portion 20 extending to the sealed side A. It is more preferable to add 5 to 10% by weight of graphite fine particles and 5 to 10% by weight of carbon short fibers to an ethylene tetrafluoride resin because they are excellent in low friction, low abrasion, mechanical strength and the like. ..

The annular support member 7 includes a radially inner annular wall 21 that contacts the flange portion 19 of the synthetic resin lip seal 6 and an axial cylindrical wall 22 that contacts the inner wall of the annular recess 13. And an outer annular wall 23 that contacts the inner surface of the outer annular wall 10.

The reinforcing ring 8 is made of synthetic resin having a thermal expansion coefficient of 5 × 10 ⁻⁵ / ° C. or more, and in this embodiment, the tip portion 15 of the rubber lip seal 5 is inclined. Therefore, the diameter of the sealed side A is slightly reduced to form a tapered shape. The minimum inner diameter is set to be larger than the outer diameter of the rotary shaft 3 so as not to directly contact the rotary shaft 3. As the material of the reinforcing ring 8, ethylene tetrafluoroethylene resin (coefficient of thermal expansion 9 × 10 ⁻⁵ / ° C.), polyphenylene sulfide resin (coefficient of thermal expansion 7 to 9 × 10 ⁻⁵ / ° C.) or the like can be used. The reinforcing ring 8 thermally expands by 0.5 to 1.0% of the diameter at an ambient temperature of 100 to 150 ° C., and has a size of about 0.15 mm when used for a general automobile air conditioning compressor. Thermal expansion occurs. The dimensional change amount of the reinforcing ring 8 is a value that does not impair the sealing performance of the lip portion 16 of the rubber lip seal 5 and is appropriately balanced with the compressive deformation of the rubber lip seal 5 due to high pressure. Further, when the reinforcing ring 8 is fitted and mounted in the annular groove 18 that is slightly wider than the axial dimension of the reinforcing ring 8, the followability to the axial runout of the rubber lip seal 5 is not impeded at all. ..

Therefore, in order to assemble the oil seal 1 of the present invention, a rubber lip seal 5 having a reinforcing ring 8 fitted in an annular groove 18 in the annular recess 13 of the housing 4, a synthetic resin After the lip seal 6 and the annular support member 7 are inserted one after another, the outer annular wall 10 is formed as described above, and each member is pressed toward the inner annular wall 11 so that the rubber lip seal 5 and The synthetic resin lip seal 6 is fixed in the housing 4 in a sealed state.

Then, with the O-ring 24 fitted in the O-ring groove 12 of the oil seal 1, the O-ring 24 is fitted in the opening of the casing 2 and the rotary shaft 3 is inserted through the center of the O-ring 24 so that the outer annular wall 10 is inserted. It is stopped by the step portion 25, and the end portion on the sealed side A is stopped by the retaining ring 26 fitted to the inner wall of the casing 2. In this state, the reinforcing ring 8 is set to be located between the tip portion 15 of the rubber lip seal 5 and the lip portion 16 of the synthetic resin lip seal 6. By doing so, it is possible to reliably prevent the reinforcing ring 8 from directly contacting the rotary shaft 3.

The oil seal 1 shown in FIG. 2 has the same structure as described above, but the reinforcing ring 8 is attached to the tip portion 15 of the rubber lip seal 5 by baking. .. When the reinforcing ring 8 is additionally provided by baking as described above, there is no possibility that the reinforcing ring 8 is displaced in the axial direction. Since other configurations are the same as the above, the same configurations are denoted by the same reference numerals and the description thereof will be omitted.

Finally, the function and effect of the reinforcing ring 8 according to the present invention will be further described with reference to FIG. The sealing pressure P of the sealed oil liquid such as a refrigerator oil or a refrigerant is uniformly applied to the surface of the tip end 15 of the rubber lip seal 5 on the sealed side A. When the rotary shaft 3 rotates due to the operation of the compressor or the like, the temperature of the lip portion 16 of the rubber lip seal 5 rises due to its frictional heat, and the temperature of the sealing oil liquid rises to soften. As a result, the tip portion 15 is pressed in the circumferential direction of the rotary shaft 3 by the action of the sealing pressure P. On the other hand, the temperature of the reinforcing ring 8 rises during operation due to heat conduction from the rubber lip seal 5 and the ambient temperature, and the temperature reaches about 100 to 150 ° C., and the thermal expansion coefficient of the material is Thermal expansion due to its high properties. Along with the thermal expansion, expansion tension F acts radially outward on the inner surface of the tip portion 15 of the rubber lip seal 5. This stabilizes the sealing pressure P and the expansion force F in balance. Therefore, even if the ambient temperature rises, the lip portion 16 of the rubber lip seal 5 excessively contacts the rotating shaft 3 due to the thermal expansion effect of the reinforcing ring 8, and the contact area and frictional resistance increase. The increase in the amount of wear of the portion 16 and the remarkable increase in frictional heat are suppressed, and the thermal deterioration of the lip portion 16 can be prevented.

Further, the mounting position of the reinforcing ring 8 is set between the tip portion 15 of the rubber lip seal 5 and the lip portion 20 of the synthetic resin lip seal 6, and the rotary shaft 3 is centered. If the inner surface of the reinforcing ring 8 is set to contact the outer surface of the tip of the lip portion 20 of the synthetic resin lip seal 6 in the inserted state, the reinforcing ring 8 will not rattle even if excessive shaft runout occurs. Even if the reinforcing ring 8 is deformed inward due to a larger sealing pressure P, the lip portion 20 can restrict the deformation. Of course, it is possible to set the reinforcing ring 8 and the lip portion 20 so that they do not come into contact with each other, and in this case, the followability to shaft runout is excellent.

[0023]

[Effect of the device]

According to the temperature-compensated oil seal of the present invention as described above, the tip of the rubber lip seal on the non-sealing side is made of a synthetic resin having a thermal expansion coefficient of 5 × 10 ^-5 / ° C or more. The ring-shaped reinforcing ring, whose minimum inner diameter is set larger than the outer diameter of the rotating shaft, is formed in close contact with the rotating shaft, which increases the temperature of the sealed oil liquid during operation and the temperature due to the friction heat with the rotating shaft. Along with this, the rubber lip seal, especially the lip portion at the tip of the rubber lip softens, and it is possible to prevent the lip portion from being deformed by the sealing pressure and excessively contacting the peripheral surface of the rotating shaft with the reinforcing ring. Also, since the minimum inner diameter of the reinforcing ring is set larger than the outer diameter of the rotating shaft, the reinforcing ring does not slide on the rotating shaft to generate frictional heat, and the contact area between the lip and the rotating shaft is small. Since it is maintained at a substantially constant level, friction heat rises excessively. Not Rukoto a result, suppression can control the thermal degradation due to frictional heat of the lip portion, it is of can be improved durability.

Further, at a tip end portion on the anti-sealing side of the rubber lip seal, which is radially outward of the lip portion of the synthetic resin lip seal, a heat expansion coefficient of 5 × 10 ⁻⁵ / ° C. or more is applied. Since the ring-shaped reinforcing ring is made of synthetic resin and has a minimum inner diameter set larger than the outer diameter of the rotating shaft, the reinforcing ring is attached even if a large shaft run-out occurs on the rotating shaft. It is possible to reliably control the rattling and displacement of the reinforcing ring without directly contacting with, and to suppress the deformation to the minimum even if a large inward deforming force acts on the reinforcing ring. ..

Further, when the reinforcing ring is attached in close contact with the annular groove formed at the tip of the rubber lip seal on the opposite side to the non-sealing side, the degree of freedom with respect to the shaft runout increases, and When it is attached by baking, the reinforcing ring stably holds its position.

[Brief description of drawings]

FIG. 1 is a partial sectional view showing a typical embodiment of the present invention.

FIG. 2 is a partial sectional view showing another embodiment of the present invention.

FIG. 3 is a partial sectional view for explaining the action of the reinforcing ring according to the present invention.

[Explanation of symbols]

1 Oil seal 2 Casing 3 Rotating shaft 4 Housing 5 Rubber lip seal 6 Synthetic resin lip seal 7 Annular support member 8 Reinforcing ring 9 Hollow annulus 10 Outer annular wall 11 Inner annular wall 12 O-ring groove 13 Annular recess 14 Base 15 Tip part 16 Lip part 17 Core ring 18 Annular groove 19 Flange part 20 Lip part 21 Inner annular wall 22 Cylindrical wall 23 Outer annular wall 24 O-ring 25 Stepped part 26 Locking ring A Sealing side B Anti-sealing side

Claims (6)

[Scope of utility model registration request] 1. An oil seal, which is hermetically mounted on a main body having a rotating shaft and sealingly engages with the rotating shaft to form a sealed chamber inside the main body, wherein a base is hermetically fixed in a housing,
A rubber lip seal having a cone-shaped lip portion formed by bulging toward the high-pressure sealing side so that the tip portion is in sliding contact with the rotating shaft is provided, and the coefficient of thermal expansion is provided at the tip portion on the non-sealing side of the rubber lip seal. Temperature compensation, characterized in that it is made of a synthetic resin having a heat resistance of 5 × 10 ⁻⁵ / ° C. or more, and a ring-shaped reinforcing ring in which the minimum inner diameter is set larger than the outer diameter of the rotating shaft is in close contact. Type oil seal. 2. The temperature-compensated oil seal according to claim 1, wherein the reinforcing ring is attached in a close contact state in an annular groove formed in the tip of the rubber lip seal on the side opposite to the sealing side. 3. The temperature-compensated oil seal according to claim 1, wherein the reinforcing ring is baked and attached to the tip of the rubber lip seal on the side opposite to the hermetically sealed side. 4. An oil seal, which is hermetically mounted on a main body having a rotary shaft and which is sealingly engaged with the rotary shaft to form a sealed chamber inside the main body, wherein a base is hermetically fixed in a housing.
A rubber lip seal in which a cone-shaped lip portion is formed by bulging toward the high-pressure sealing side so that the tip portion slides on the rotating shaft, and is located in the housing on the anti-sealing side of the rubber lip seal, And a synthetic resin lip seal having a cone-shaped lip portion extending from the flange portion inward in the radial direction of the lip portion while sealingly fixing the flange portion to the base portion, and anti-sealing of the rubber lip seal. Of the rotary shaft, which is made of a synthetic resin having a thermal expansion coefficient of 5 × 10 ⁻⁵ / ° C. or more at the outer end in the radial direction of the lip portion of the synthetic resin lip seal. A temperature-compensated oil seal, characterized in that a ring-shaped reinforcing ring whose minimum inner diameter is set larger than the outer diameter is in close contact. 5. The temperature-compensated oil seal according to claim 4, wherein the reinforcing ring is attached in a close contact state in an annular groove formed in the tip of the rubber lip seal on the side opposite to the sealing side. 6. The temperature-compensated oil seal according to claim 4, wherein the reinforcing ring is baked and attached to the tip of the rubber lip seal on the side opposite to the hermetically sealed side.