JP2005121164A - Sealing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sealing device having an excellent hermeticity that hardly causes a pressure difference even when used in an environment where a pressure difference is likely to occur between the inside and the outside of a sealed space.
A space 14 formed between an inner peripheral surface of an outer ring 1 of an automobile hub unit and an outer peripheral surface of an inner ring equivalent member 3 in which rolling elements 10 and 10 are arranged is formed by a seal device 12 and a seal ring 13. Sealed. A through hole 30 is provided in the metal core 15 of the sealing device 12, and the opening of the through hole 30 is blocked by a stretched porous polytetrafluoroethylene film 31 that has been coated with a fluoropolymer composition. ing.
[Selection] Figure 2

Description

  The present invention relates to a sealing device.

Some rubber seal devices used for rolling bearings have notched air holes on the outer diameter side, etc. for the purpose of adjusting internal pressure, but air is used to prevent liquid from entering the inside. Those that do not have holes are becoming common.
JP-A-5-320255 Japanese Patent Laid-Open No. 7-126428 JP-A-11-51192

However, a rubber seal device that does not have an air hole has a certain sealing property, but a pressure difference between the inside and the outside of the space sealed by the rubber seal device, such as when a sudden temperature change occurs. When used in an environment in which the rubber lip is generated, the rubber lip portion may be instantaneously deformed, or in the worst case, the rubber lip portion may be rolled up, resulting in a gap. In this case, foreign matters such as water and dust gradually enter the sealed space, adversely affecting the internal members (for example, rolling bearings), and in the worst case, there is a risk of causing problems.
Therefore, the present invention solves the problems of the conventional sealing device as described above, prevents a pressure difference between the inside of the sealed space and the outside, and prevents foreign matter from entering the sealed space. It is an object of the present invention to provide a sealing device with excellent sealing performance that suppresses intrusion.

In order to solve the above problems, the present invention has the following configuration. That is, the sealing device according to claim 1 of the present invention is a sealing device that is disposed between two spaces and seals one space from the other space, and has a through hole that communicates the two spaces. It is characterized in that the through hole is closed with a ventilation material having a property that gas passes but liquid does not pass.
A sealing device according to a second aspect of the present invention is the sealing device according to the first aspect, wherein a sealing member made of a rubber material composition for sealing and the sealing member integrally joined to the sealing member And a reinforcing member that reinforces, wherein the through-hole provided in the reinforcing member is closed with the porous ventilation material.

Furthermore, a sealing device according to a third aspect of the present invention is the sealing device according to the first or second aspect, wherein the ventilation member is a polytetrafluoroethylene film.
Furthermore, the sealing device of claim 4 according to the present invention is the sealing device of claim 3, wherein the polytetrafluoroethylene film is a stretched film and is made of polytetrafluoroethylene. A large number of fibrous materials are aggregated or connected to form a porous structure. The fibrous material includes 1 part by mass of a fluorinated polymer having a fluorinated aliphatic ring structure in the main chain, and a polyfluoroalkyl group. It is covered with a fluorine-containing polymer composition comprising 0.01 to 100 parts by mass of a fluorine-containing polymer having

  With such a configuration, the inside and the outside of the space sealed by the sealing device are communicated by the through-hole, so that the pressure difference between the inside and the outside of the sealed space is likely to occur (for example, suddenly Pressure difference is unlikely to occur even when used in a case where a large temperature change occurs. Therefore, there is almost no possibility that the sealing device is deformed due to the pressure difference and a gap is generated, and excellent sealing performance is maintained, so that foreign matters such as water and dust can enter the sealed space or enter the sealed space. It is difficult for the enclosed lubricant to leak out. In addition, since the through hole is closed with a ventilation material that has the property of allowing gas to pass but not liquid, liquids such as water and oil, and solids such as dust may enter the sealed space through the through hole. There is no.

  Even when used in an environment in which a pressure difference tends to occur between the inside and the outside of the sealed space, the sealing device of the present invention hardly causes a pressure difference and has excellent sealing properties.

First, the ventilation material used for the sealing device of the present invention will be described. The type of the ventilation material is not particularly limited as long as it has a property that gas passes and liquid does not pass. A porous body is particularly preferred, but it may be woven or non-woven. Moreover, the material is not particularly limited, and resin, ceramic, or the like is preferable.
Here, the stretched porous polytetrafluoroethylene film that is particularly preferably used as the ventilation material will be described in detail. The stretched porous polytetrafluoroethylene film is formed from a paste prepared by mixing fine powder of tetrafluoroethylene (PTFE) and a molding aid, and after removing the molding aid from the resulting molded article, the high temperature and high speed It is obtained by stretching at, and further firing.

  In the case of uniaxial stretching, the nodes (folded crystals) are in the form of thin islands extending perpendicular to the stretching direction, and the fibrils (folded crystals are unwound and drawn out by stretching to connect the nodes). Linear molecular bundles) are oriented in the stretching direction. Thereby, the space defined between the fibrils or between the fibrils and the nodes has a fine network structure in which holes are formed. In the case of biaxial stretching, the fibrils spread radially, the nodes connecting the fibrils are scattered in islands, and there are a lot of spaces defined by the fibrils and the nodes. It has become. The stretched porous polytetrafluoroethylene film can be used as an air-permeable material even if it is produced by any method of uniaxial stretching and biaxial stretching.

  The average pore diameter of the pores of the stretched porous polytetrafluoroethylene film can be appropriately set depending on the stretch ratio, but is preferably 0.1 μm or more and 15 μm or less. If the average pore diameter of the pores exceeds 15 μm, the air permeability is excellent, but the waterproof property may be lowered. Also, if the average pore diameter is less than 0.1 μm, the pores are too small, making it difficult to accurately produce a thin film such as a film, and insufficient stretching during production. Therefore, stable fiber orientation cannot be obtained, and the quality is not stable. In order to make such inconvenience difficult to occur, the average pore diameter is more preferably 0.5 μm or more and 2 μm or less.

Further, the porosity of the stretched porous polytetrafluoroethylene film can be appropriately set within a range of 10% or more and 90% or less depending on the stretch ratio, but considering the strength, durability, etc. of the film, it is 30% or more. A range of 85% or less is preferred.
The stretched porous polytetrafluoroethylene film has a porous structure due to a fine network structure in which the above-described fibrils and nodes (both correspond to fibrous materials which are constituent elements of the present invention) are connected. The surface of the fibrils and nodes is composed of 1 part by mass of a fluoropolymer having a fluorinated aliphatic ring structure in the main chain, and 0.01 part by mass or more and 100 parts by mass or less of a fluorinated polymer having a polyfluoroalkyl group. It is preferable to coat with a fluorine-containing polymer composition comprising, because the water resistance, oil repellency and oil resistance of the stretched porous polytetrafluoroethylene film are improved.

  The fluorine-containing polymer composition used as a coating material comprises a fluorine-containing polymer having a polyfluoroalkyl group having excellent water and oil repellency and a fluorine-containing polymer having a fluorine-containing aliphatic ring structure having excellent film forming properties. Since they are mixed, the formed film has excellent durability and water / oil repellency, and thus the durability and water / oil repellency of the stretched porous polytetrafluoroethylene film are improved.

  Examples of the fluorine-containing polymer having a fluorine-containing aliphatic ring structure in the main chain include a polymer obtained by polymerizing a monomer having a fluorine-containing aliphatic ring structure, and a fluorine-containing monomer having at least two polymerizable double bonds. A polymer having a ring structure in the main chain obtained by cyclopolymerization of is preferred. Specific examples of the polymer obtained by polymerizing a monomer having a fluorine-containing aliphatic ring structure include monomers having a fluorine-containing aliphatic ring structure such as perfluoro (2,2-dimethyl-1,3-dioxole). Examples thereof include homopolymers and copolymers of the monomers and radical polymerizable monomers such as tetrafluoroethylene. Specific examples of the polymer having a cyclic structure in the main chain obtained by cyclopolymerizing a fluorine-containing monomer having at least two polymerizable double bonds include perfluoro (allyl vinyl ether), perfluoro (butenyl). Cyclized polymers of monomers such as vinyl ether) and copolymers of such monomers with radical polymerizable monomers such as tetrafluoroethylene.

  The fluorine-containing polymer having a fluorine-containing aliphatic ring structure is preferably a polymer having a ring structure in the main chain, but those containing 20 mol% or more of the ring structure in the repeating unit are water and oil repellent and It is preferable from the viewpoint of mechanical properties. The molecular weight of the fluorine-containing polymer having a fluorine-containing aliphatic ring structure is preferably 0.01 dl / g or more and 3.0 dl / g or less in terms of intrinsic viscosity. When the intrinsic viscosity is less than 0.01 dl / g, the film formability is inferior, and when it is more than 3.0 dl / g, the solubility in the solvent is deteriorated, and the coating process by the dipping process becomes difficult.

  Examples of the fluoropolymer having a polyfluoroalkyl group include a homopolymer obtained by radical polymerization of an α, β-unsaturated monomer having a polyfluoroalkyl group, and an α, β- having the polyfluoroalkyl group. A copolymer of an unsaturated monomer and a radically polymerizable unsaturated monomer is preferred. The α, β-unsaturated monomer having a polyfluoroalkyl group has a structure in which the polyfluoroalkyl group is bonded to a polymerizable unsaturated group directly or via a divalent linking group. Examples of the polyfluoroalkyl group usually include those in which a hydrogen atom in a hydrocarbon group such as a linear or branched alkyl group or alkenyl group is substituted with a fluorine atom. It may have a structure. In general, the polyfluoroalkyl group has 1 to 20 carbon atoms, preferably 4 to 16 carbon atoms.

  As the α, β-unsaturated monomer having a polyfluoroalkyl group, an acrylate monomer and a methacrylate monomer are preferable because of good polymerizability. Examples of the radical polymerizable unsaturated monomer include 2-ethylhexyl methacrylate, stearyl methacrylate, cyclohexyl methacrylate, methacrylamide, vinyl fluoride, and butadiene.

In the copolymerization of the α, β-unsaturated monomer having a polyfluoroalkyl group and the aforementioned radical polymerizable unsaturated monomer, the former ratio is preferably 60% by mass or more, and 80% by mass. % Or more is more preferable.
Further, the number average molecular weight of the fluoropolymer having a polyfluoroalkyl group is preferably from 1,000 to 1,000,000, and particularly preferably from 1,000 to 200,000 in consideration of solubility in a solvent.

  Furthermore, the ratio of the fluorinated polymer having a fluorinated aliphatic ring structure in the main chain to the fluorinated polymer having a polyfluoroalkyl group is usually 0.01% by mass with respect to 1 part by mass of the former. It is preferable to set it as mass parts or more and 100 mass parts or less. If the latter is less than 0.01 parts by mass, there is a disadvantage that the oil repellency becomes insufficient, and if it exceeds 100 parts by mass, the film-forming property is insufficient and the durability of the coating is lowered. In order to make it difficult for such an inconvenience to occur, it is more preferable that the latter is 0.5 parts by mass or more and 20 parts by mass or less with respect to 1 part by mass of the former.

  Furthermore, when a stretched porous polytetrafluoroethylene film is coated with a fluoropolymer composition comprising a mixture of both, a solution in which the fluoropolymer composition is dissolved is immersed by a method such as immersion or spraying. It may be brought into contact with the stretched porous polytetrafluoroethylene film. If it does so, it is possible to perform a coating process without impairing the air permeability of the stretched porous polytetrafluoroethylene film. The concentration of the fluoropolymer composition in the solution is usually about 0.01 to 5% by mass, and the type of the solvent is preferably a fluorine-based solvent such as perfluorohexane. In addition, after making a solution contact an extending | stretching porous polytetrafluoroethylene film, you may remove a solvent by air-drying or heat-processing at the temperature of about 50-200 degreeC.

  Examples of the coating material that imparts oil repellency to the stretched porous polytetrafluoroethylene film include the following amorphous fluororesins in addition to the above-mentioned fluoropolymer composition. That is, it is a polymer having a fluorine-containing aliphatic ether ring structure in the main chain. Specifically, it is obtained by cyclopolymerizing a monomer composed of alkenyl vinyl ether such as perfluoro (allyl vinyl ether) or perfluoro (butenyl vinyl ether). Or obtained by copolymerizing these monomers with radically polymerizable monomers such as tetrafluoroethylene, chlorotrifluoroethylene, and perfluoro (methyl vinyl ether). This amorphous fluororesin preferably has a functional group such as a carboxyl group introduced at the end or the like in order to improve adhesion to the substrate.

  Since this amorphous fluororesin has the property of being dissolved in a perfluoro solvent such as perfluoro (2-butyltetrahydrofuran), it is necessary to apply a coating treatment to the stretched porous polytetrafluoroethylene film. The stretched porous polytetrafluoroethylene film may be dipped in a solution in which an amorphous fluororesin is dissolved in a fluoro solvent at a concentration of about 1 to 10% by mass and dried.

Since the thickness of the above-mentioned fluoropolymer composition or amorphous fluororesin coating depends on the solution concentration, the concentration is appropriately adjusted so as to obtain a desired thickness. In order to impart sufficient oil repellency, the film thickness is preferably 0.01 μm or more and 1 μm or less. When the film thickness is less than 0.01 μm, it is difficult to form a film having a stable thickness, and it is difficult to ensure sufficient oil repellency. On the other hand, even if the film thickness exceeds 1 μm, the oil repellency is not further improved, and it is difficult to form a film having a uniform thickness. Furthermore, there exists a possibility of inhibiting the air permeability of the stretched porous polytetrafluoroethylene film. In order to make it difficult to cause such inconvenience, the film thickness is more preferably 0.1 μm or more and 0.5 μm or less.
In order to improve the adhesion (adhesiveness) between the coating and the substrate, it is more preferable to perform a heat treatment at about 100 to 120 ° C. for about 0.5 to 2 hours, or to perform a primer treatment on the substrate. is there.

Hereinafter, embodiments of the sealing device according to the present invention will be described in detail.
[First embodiment]
An automotive hub unit which is an example of a rolling bearing provided with the sealing device of the present invention will be described with reference to FIGS.
This hub unit supports the wheel of an automobile rotatably with respect to a suspension device. The outer ring 1 which is a stationary side member is supported and fixed to the suspension device by a mounting portion 2 formed on the outer peripheral surface thereof, and does not rotate even when the automobile is used. On the inner diameter side of the outer ring 1, an inner ring equivalent member 3, which is a rotation side member, is arranged concentrically with the outer ring 1, and the inner ring equivalent member 3 rotates when the automobile is used. The inner ring equivalent member 3 includes a hub 4 and an inner ring 5, and a mounting flange 7 is formed on the outer peripheral surface of the outer end portion of the hub 4, and a wheel is fixed to the mounting flange 7. ing. In the first embodiment, for convenience of explanation, in a state where the hub unit is attached to the vehicle, an end portion facing the outer side in the width direction of the vehicle (left side in FIGS. 1 and 2) is referred to as an “outer end”. An end facing the center in the width direction of the vehicle (right side in FIGS. 1 and 2) is referred to as an “inner end”.

  Further, double-row outer ring raceways 8, 8 are formed on the inner peripheral surface of the outer ring 1, and inner ring raceways 9, 9 are formed on the outer peripheral surface of the intermediate portion of the hub 4 and the outer peripheral surface of the inner ring 5. A plurality of rolling elements 10 and 10 are disposed between the outer ring raceways 8 and 8 and the inner ring raceways 9 and 9, respectively, so that the inner ring equivalent member 3 is rotatable. In addition, each rolling element 10 and 10 is hold | maintained so that rolling is possible by the holder | retainers 11 and 11, respectively. Further, in the example of FIG. 1, a ball is used as the rolling element 10, but in the case of a heavy vehicle hub unit, a tapered roller may be used as the rolling element.

  Further, a sealing device 12 is attached between the inner peripheral surface of the inner end of the outer ring 1 and the outer peripheral surface of the inner end of the inner ring 5, and between the outer peripheral surface of the outer end of the outer ring 1 and the outer peripheral surface of the intermediate portion of the hub 4. A seal ring 13 is attached. The sealing device 12 and the seal ring 13 close the openings at both ends of the space 14 formed between the inner peripheral surface of the outer ring 1 and the outer peripheral surface of the inner ring equivalent member 3 and in which the rolling elements 10 and 10 are arranged. It is peeling off.

  The seal ring 13 that closes the outer end opening of the space 14 includes a cored bar 26 and a seal member 27 each formed in an annular shape. Of these, the cored bar 26 is integrally formed by subjecting a metal plate such as a low-carbon steel plate to punching processing such as press processing and plastic processing. The seal member 27 is made of an elastic material such as an elastomer such as rubber. Such a sealing member 27 is joined to the cored bar 26 by molding with the cored bar 26 set in the cavity of the molding die. The seal member 27 seals the outer end opening of the space 14 by bringing the tip edges of the seal lips 28 a, 28 b, 28 c provided on the seal member 27 into direct contact with the surface of the hub 4.

On the other hand, as shown in FIG. 2, the sealing device 12 that closes the inner end opening of the space 14 includes a cored bar 15 (corresponding to a reinforcing member that is a constituent element of the present invention) and a seal each formed in an annular shape. A seal ring 17 formed of the member 16 and a slinger 18 that is also formed in an annular shape are provided.
Among these, the slinger 18 is integrally formed by performing punching processing such as press working and plastic working on a metal plate having excellent corrosion resistance such as a stainless steel plate. Such a slinger 18 has an inner diameter side cylindrical portion 21 that can be fitted and fixed to the outer peripheral surface of the inner end portion of the inner ring 5, and radially outward from the inner end edge (right end edge in FIG. 2) of the inner diameter side cylindrical portion 21. It has an L-shaped cross section including an outer ring portion 22 that is bent in a circle, and has a circular shape as a whole.

  Further, the core bar 15 constituting the seal ring 17 is integrally formed by performing a punching process such as a press process and a plastic process on a metal plate such as a low carbon steel plate. The cored bar 15 may be made of a resin material or ceramics. Such a metal core 15 includes an outer diameter side cylindrical portion 19 that can be fitted and fixed to the inner peripheral surface of the inner end portion of the outer ring 1, and an axial outer end edge (left end edge in FIG. 2) of the outer diameter side cylindrical portion 19. The cross section is substantially L-shaped and includes an inner annular portion 20 that is bent radially inward from the inside, and has an annular shape as a whole.

  Further, as shown in FIG. 2, the cored bar 15 is provided with a through hole 30 having a diameter of 2 mm, for example, and the opening on the inner end side of the through hole 30 is covered with the aforementioned fluoropolymer composition. The stretched porous polytetrafluoroethylene film 31 (trade name Gore-Tex Oreovent filter patch type manufactured by Japan Gore-Tex Co., Ltd.) is closed. This stretched porous polytetrafluoroethylene film 31 is composed of 1 part by mass of a fluoropolymer having a fluorinated aliphatic ring structure in the main chain and 0.01 part by mass or more and 100 parts by mass of a fluoropolymer having a polyfluoroalkyl group. And a coating treatment for coating a fluoropolymer composition comprising: The stretched porous polytetrafluoroethylene film 31 may block the opening on the outer end side of the through-hole 30 or may block the opening on both sides.

  The stretched porous polytetrafluoroethylene film 31 is adhered to the cored bar 15 by a pressure-sensitive adhesive 32 applied in a ring shape to the outer periphery thereof, and the central circle portion to which the pressure-sensitive adhesive 32 is not applied is the through hole 30. It is arranged to cover the opening. In addition, the diameter of the center circular part to which the adhesive 32 is not applied is 2.5 mm, the thickness of the stretched porous polytetrafluoroethylene film 31 is 0.25 mm, and the pores of the stretched porous polytetrafluoroethylene film 31 The average pore diameter is 3 μm.

  Further, the core metal 15 is preliminarily baked with a phenol-based vulcanized adhesive for rubber, and is made of rubber by vulcanizing and bonding in a mold together with unvulcanized rubber (for example, nitrile rubber). The seal member 16 and the cored bar 15 are integrally joined. At this time, if the outer peripheral portion of the stretched porous polytetrafluoroethylene film 31 is covered with rubber, the stretched porous polytetrafluoroethylene film 31 is prevented from falling off.

  The seal member 16 includes three seal lips 23, 24, and 25 on the outer side, the middle side, and the inner side, and the base end portion is fixed to the core metal 15. Then, with respect to the inner and outer directions of the space 14, the tip edge of the outer seal lip 23 located on the outermost side is brought into sliding contact with the inner surface of the outer ring portion 22 of the slinger 18, and the tips of the intermediate seal lip 24 and the inner seal lip 25. The edge is brought into sliding contact with the outer peripheral surface of the inner diameter side cylindrical portion 21 of the slinger 18 to prevent leakage of grease from the space 14 and water, muddy water, oil, dust, etc. from the outside to the space 14. Prevents foreign material from entering.

  When the automobile is used, the automobile hub unit rotates to generate heat, and a pressure difference is likely to occur between the space 14 sealed by the sealing device 12 and the seal ring 13 and the external space of the automobile hub unit. 14 and the external space of the automobile hub unit are communicated with each other through a through-hole 30, and the stretched porous polytetrafluoroethylene film 31 has air permeability. Therefore, even if heat is generated, a pressure difference hardly occurs. .

  Therefore, there is almost no possibility that the sealing device 12 is deformed due to the pressure difference and a gap is generated, and excellent sealing performance is maintained, so that foreign matters such as water and dust enter the space 14 or are enclosed in the space 14. It is difficult for the applied lubricant to leak into the external space. Further, since the stretched porous polytetrafluoroethylene film 31 has a property of breathing but does not allow liquid to pass through, liquids such as water and oil and solids such as dust pass through the through holes 30. It does not enter the space 14. Therefore, the automotive hub unit is excellent in various performances such as durability.

[Second Embodiment]
A water pump incorporating a rolling bearing provided with the sealing device of the present invention will be described with reference to FIG. 3 and FIG. 4 showing an enlarged view of part A of FIG. In addition, about the part similar to the above-mentioned 1st embodiment among the structure of the sealing apparatus in 2nd embodiment, an effect | action and an effect, the description is abbreviate | omitted and only a different part is demonstrated.
The water pump 101 of FIG. 3 is for circulating the cooling water of the automobile engine. FIG. 3 shows a drive mechanism for rotating the water pump 101 and the cooling fan 102 for sending air to the radiator for radiating the cooling water by a single rotating shaft 103.

  The rotating shaft 103 of the water pump 101 is rotatably supported by the bearing unit 104. That is, the rotation shaft 103 is rotatably supported at its intermediate portion by the bearing unit 104 supported by the housing 105 of the water pump 101. In addition, an impeller 106 is attached to an end portion (right end portion in FIG. 3) located in the housing 105 among the end portions of the rotating shaft 103, and an end portion (left end portion in FIG. 3) similarly located outside the housing 105. Is attached with a driven pulley 107. An endless belt 108 is stretched between the driven pulley 107 and a driving pulley fixed to the end of a crankshaft (not shown) so that the rotary shaft 103 is driven to rotate during engine operation. .

  The cooling fan 102 is supported by an inner hub 109 for fixing the driven pulley 107 to the end of the rotating shaft 103 via a rolling bearing 110 and a fluid coupling 111. On the other hand, between the housing 105 and a portion of the rotating shaft 103 between the impeller 106 and the bearing unit 104 and the housing 105, a mechanical that prevents the coolant flowing in the housing 105 from entering the bearing unit 104 side. Further, a seal 112 is provided. Further, in order to prevent cooling water that has entered the bearing unit 104 side beyond the mechanical seal 112 from entering the bearing unit 104, the impeller side of the bearing unit 104 (FIGS. 3 and 4). 4 is provided with a sealing device 113 as shown in FIG.

The seal device 113 is formed in a ring shape, and a seal ring 117 composed of a cored bar 115 (corresponding to a reinforcing member which is a constituent element of the present invention) and a seal member 116 each formed in an annular shape. And a slinger 118.
Among these, the slinger 118 is similar to the slinger 18 described in the first embodiment described above. It is made of a metal plate with excellent corrosion resistance against corrosion caused by oil, muddy water, etc. Such a slinger 118 is formed from an inner diameter side cylindrical portion 121 that can be fitted and fixed to the outer peripheral surface of the rotation shaft 103 that is a rotation side member, and an impeller side end edge (right end edge in FIG. 4) of the inner diameter side cylindrical portion 121. An outer circular ring portion 122 bent outward in the diameter direction, and a second inner cylindrical portion bent substantially perpendicularly from the outer end edge of the outer circular ring portion 122 to the axially opposite impeller side (left side in FIG. 4) 126 and a substantially U-shaped cross section with a circular shape as a whole.

  Further, the core metal 115 constituting the seal ring 117 is formed in an annular shape by subjecting a metal plate such as a low carbon steel plate to punching processing such as press processing and plastic processing. The core metal 115 may be made of a resin material or ceramics. The cored bar 115 is provided with a through hole 130 as in the case of the first embodiment, and the opening on the impeller side of the through hole 130 is adhered with an adhesive 132 as in the case of the first embodiment. The stretched porous polytetrafluoroethylene film 131 is closed. Further, as in the case of the first embodiment, the phenolic rubber vulcanized adhesive is baked on the core metal 115 in advance, and together with unvulcanized rubber (for example, nitrile rubber) in the mold. By vulcanizing and bonding, the seal member 116 made of rubber and the core metal 115 are integrally joined. At this time, if the outer peripheral portion of the stretched porous polytetrafluoroethylene film 131 is covered with rubber, the stretched porous polytetrafluoroethylene film 131 is prevented from falling off.

  Such a seal member 116 locks the outer peripheral edge of the outer ring 119a, which is a stationary side member constituting the bearing unit 104, on the inner peripheral surface of the end portion of the outer ring 119 over the entire circumference without gaps. Has been. The seal member 116 includes two outer seal lips 123, 124 and one inner seal lip 125, and the second outer seal lip 124 of the three seal lips 123, 124, 125 and The inner seal lip 125 is brought into sliding contact with the inner diameter side cylindrical portion 121 of the slinger 118 and the outer peripheral surface of the rotary shaft 103, and the first outer seal lip 123 is brought into sliding contact with the outer peripheral surface of the second inner diameter side cylindrical portion 126. ing.

[Third embodiment]
An electromagnetic clutch for an air conditioner in which a rolling bearing having the sealing device of the present invention is incorporated will be described with reference to FIGS. In addition, about the part similar to 1st embodiment mentioned above among the structure of the sealing apparatus in 3rd embodiment, an effect | action and an effect, the description is abbreviate | omitted and only a different part is demonstrated.

  The air conditioner electromagnetic clutch shown in FIG. 5 is attached to the air conditioner compressor 201 and transmits engine power (not shown) to the drive shaft 202 of the compressor 201. In other words, the electromagnetic clutch pulley 205 is rotatably supported by the cylindrical portion 203 protruding from the housing of the compressor 201 so as to cover the drive shaft 202 of the compressor 201 via the double-row angular contact ball bearing 210, and the power of the engine Is transmitted to the electromagnetic clutch pulley 205 via a crank pulley and a belt (both not shown). The friction plate 206 arranged at the end of the electromagnetic clutch pulley 205 is attracted to the electromagnetic clutch pulley 205 by the electromagnetic force of the electromagnetic coil 207, whereby the transmitted engine power is transmitted to the compressor 201. Is to be driven.

  The double row angular contact ball bearing 210 incorporated in such an electromagnetic clutch for an air conditioner is equipped with a seal device 212 for sealing the bearing internal space. FIG. 6 is an enlarged cross-sectional view showing only one row of the double row angular contact ball bearing 210 in an enlarged manner. The configuration of the seal device 212 is substantially the same as that of a contact-type rubber seal device generally used for rolling bearings, and is composed of a cored bar 215 as a reinforcing member and a seal member 216 made of a rubber material composition. However, as in the case of the first and second embodiments described above, the cored bar 215 is provided with a through hole 230, and the opening thereof is closed with a stretched porous polytetrafluoroethylene film 231.

Therefore, even when heat generation occurs due to the use of the electromagnetic clutch for the air conditioner and a pressure difference is likely to occur between the bearing inner space of the double row angular contact ball bearing 210 and the outside, the pressure difference is less likely to occur. Sealing performance is maintained.
The above-described embodiments are merely examples of the present invention, and the present invention is not limited to the above-described embodiments. For example, in the first to third embodiments, the through hole is closed by covering the opening of the through hole with a ventilation material, but even if the through hole is blocked by filling the ventilation material partially or entirely in the through hole. Good. Moreover, in 1st-3rd embodiment, although the ventilation material was a film form, other shapes, such as a sheet form, may be sufficient.

[For sealing test]
Using a double-row angular contact ball bearing (inner diameter: 35 mm, outer diameter: 45 mm, width: 20 mm) shown in FIG. 6, a static water injection test was conducted assuming the use environment in an electromagnetic clutch. That is, after the bearing is heated at 100 ° C. for 1 hour, 20 ° C. water is sprayed onto the seal portion for 5 minutes at a water injection amount of 500 ml / min to quench the bearing under severer conditions than the bearing internal space becomes negative pressure. A test was conducted. Then, the amount of water penetrating into the bearing was measured based on the increase in mass of the bearing after the test, and the sealing performance of the sealing device was evaluated based on the increase in mass. The seal lip (seal member) of the seal device was made of acrylic rubber.

  The double row angular contact ball bearing shown in FIG. 6 has a through-hole provided in the sealing device, and this through-hole is closed with a stretched porous polytetrafluoroethylene film, so that air can pass through the through-hole. Yes (no water passes). Therefore, even if it is cooled rapidly in the above test, the pressure is adjusted and the bearing internal space does not become negative pressure, so there is no instantaneous swell of the seal lip, and no water enters the bearing internal space. Did not happen.

  On the other hand, the double row angular contact ball bearing of the same configuration as the double row angular contact ball bearing shown in FIG. 6 except that a general seal device (that is, a seal device having no through hole) is mounted. When a static water injection test similar to that described above was performed using a ball bearing, the inner space of the bearing became negative pressure when it was rapidly cooled, and the seal lip swelled momentarily, causing a slight amount of water into the inner space of the bearing. (20 mg) entered.

  The sealing device of the present invention is suitable as a rolling bearing sealing device or an oil seal, and can be used particularly for a rolling bearing for a vehicle wheel, a rolling bearing for an electromagnetic clutch, or the like.

It is sectional drawing which shows the structure of the hub unit for motor vehicles. It is an expanded sectional view of the sealing device incorporated in the hub unit for automobiles of FIG. It is sectional drawing which shows the structure of a water pump. FIG. 4 is an enlarged sectional view of a sealing device incorporated in the water pump of FIG. 3. It is sectional drawing which shows the structure of the electromagnetic clutch for air conditioners. FIG. 6 is an enlarged cross-sectional view of a double row angular contact ball bearing incorporated in the electromagnetic clutch for an air conditioner of FIG. 5.

Explanation of symbols

12, 113, 212 Sealing device 14 Space 15, 115, 215 Core metal 16, 116, 216 Seal member 30, 130, 230 Through hole 31, 131, 231 Stretched porous polytetrafluoroethylene film

Claims (4)

  A sealing device that is disposed between two spaces and seals one space from the other by sealing it with a through hole that communicates the two spaces, and has a property of allowing gas to pass but not liquid to pass. A sealing device, wherein the through hole is closed with a material.   A sealing member made of a rubber material composition that seals, and a reinforcing member that is integrally joined to the sealing member and reinforces the sealing member, wherein the through hole provided in the reinforcing member is porous The sealing device according to claim 1, wherein the sealing device is closed with a ventilation material.   The sealing device according to claim 1, wherein the ventilation material is a polytetrafluoroethylene film.   The film made of polytetrafluoroethylene is a stretched film and has a porous structure formed by aggregation or connection of many fibrous materials composed of polytetrafluoroethylene, and the fibrous material Is a fluorine-containing polymer comprising 1 part by mass of a fluorine-containing polymer having a fluorine-containing aliphatic ring structure in the main chain and 0.01 to 100 parts by mass of a fluorine-containing polymer having a polyfluoroalkyl group. The sealing device according to claim 3, wherein the sealing device is coated with a composition.

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