JP2014181814A - Cage for rolling bearing, and rolling bearing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cage for a self-lubrication rolling bearing capable of improving bearing life at a high temperature and realizing low torque by being incorporated in the rolling bearing, and to provide the rolling bearing incorporating the same.SOLUTION: A cage 1 for a rolling bearing holds rolling elements of a rolling bearing, and includes a cage body composed of a molding of a synthetic resin composition. The cage body has a surface communication hole; the surface communication hole is impregnated with an ionic liquid having an imidazolium cation structure and the like; and an impregnation rate represented as a volume of the ionic liquid to the total volume of the cage body including a part of the surface communication hole, is 20% or more and less than 50%.

Description

  The present invention relates to a resin-made rolling bearing cage having self-lubricating properties and a rolling bearing incorporating the same.

  Rolling bearings filled with grease or the like are often used for general purposes such as automobiles and industrial equipment because they have a long service life and do not require an external lubrication unit. On the other hand, various self-lubricating bearings have been proposed because they have grease agitation resistance inside the bearing, a large torque, and the possibility of grease leakage. For example, there is known a bearing in which a solid lubricant obtained by encapsulating a lubricant or a mixture of grease and a synthetic resin into a solid state through a heating / cooling process is known (Patent Document 1 and Patent Document). 2). Further, as a cage constituting a rolling bearing, there is known a bearing made of a synthetic resin composition porous body having a predetermined communication hole structure and impregnated with a lubricating oil (see Patent Document 3).

  Further, there is known a rolling bearing used for a position control flywheel or the like, which incorporates a porous body cage impregnated with an ionic liquid (see Patent Document 4). In this bearing, examples of materials for the cage body include metals such as iron-based and copper-based sintered alloys, heat-resistant resins such as phenol resins and polyimide resins, and ceramics such as silicon nitride, aluminum oxide, and silicon carbide. In view of processability, it is preferably formed from a heat-resistant resin, and the porosity is preferably 2 to 10% by volume in order to obtain sufficient lubrication performance. Further, this bearing can be provided with a porous lubricant holding member separately from the cage, and as the lubricant holding member, polypropylene, polyethylene, polyethylene terephthalate, polybutylene terephthalate, nylon 6, nylon 66, There are mentioned those obtained by impregnating an ionic liquid into a felt made of a fiber such as aromatic nylon or polyacrylonitrile.

Japanese Patent Application Laid-Open No. 08-183982 Japanese Patent Laid-Open No. 08-021450 JP 2005-344906 A JP 2007-139127 A

  Rolling bearings are often used in a high temperature environment. For example, a film forming apparatus such as an electronic component, an optical system, liquid crystal glass, or a semiconductor manufacturing apparatus, or a thin film manufacturing apparatus for a solar cell requires a manufacturing process for performing an organic or inorganic thin film forming process. A surface treatment apparatus such as a sputtering apparatus or a vapor deposition apparatus (PVD, CVD) is used for the film formation process, and an in-line apparatus using a belt conveyance or a multi-chamber apparatus using a robot conveyance is used to move a processed product. In these apparatuses, there is a movable part in the vacuum processing chamber, and the rolling bearing used for the movable part is required to be compatible with air and vacuum, low dust generation, low torque, and high temperature durability (heat resistance degradation).

  In the solid lubricants of Patent Document 1 and Patent Document 2, combinations of resin and lubricating oil are limited, and heat resistance is not necessarily high in resins such as polyethylene and urethane. For this reason, it is difficult to use in a high temperature environment such as 150 ° C. or higher. In addition, since sufficient strength cannot be secured due to the limitation of the resin, the solid lubricant itself cannot be a structural material such as a cage, and the rolling surface is filled in the space around the steel plate cage. Lubricating oil is supplied.

  In Patent Document 3, an inorganic salt that can be extracted in a subsequent manufacturing process is blended as a pore-forming agent, then molded, and the pore-forming agent is extracted to form a porous cage. A combination of resin and lubricating oil can be made arbitrary by impregnating the communicating hole portion with lubricating oil after forming the cage. In addition, hydrocarbon oil such as poly α-olefin oil or fluorine oil is used as the lubricating oil to be impregnated. However, hydrocarbon oils have a low decomposition temperature and may not be used in a high temperature environment such as those described above. On the other hand, although fluorine oil is excellent in heat resistance, it is highly corrosive, so the bearing life is not necessarily longer than that of hydrocarbon oil. In use, grease is mainly used together, and the bearing torque increases due to the stirring resistance of the grease. From these viewpoints, a bearing having high heat resistance, low corrosiveness to bearing steel, excellent bearing life at high temperature, and low torque cannot be easily obtained.

  As in Patent Document 4, when the amount of the lubricant is 2 to 10% with respect to the cage volume, the viscosity of the ionic liquid is lowered particularly when the high-speed rotation is performed at a high temperature, and the lubricant is quickly scattered by the centrifugal force. There is a possibility that a sufficient bearing life cannot be obtained. In addition, the porous resin obtained by impregnating felt with thermosetting resin, forming a ring by sheet winding method, and impregnating lubricant is not necessarily continuous pores, and impregnate all holes with lubricant. There is a possibility that the strength of the material may be reduced.

  The present invention has been made in order to cope with such a problem, and by incorporating it in a rolling bearing, it is excellent in bearing life at high temperature, and a self-lubricating rolling bearing cage capable of realizing low torque, And it aims at provision of the rolling bearing incorporating this.

  A rolling bearing cage of the present invention is a rolling bearing cage that holds rolling elements of a rolling bearing, and the cage includes a cage body that is a molded body of a synthetic resin composition, and the cage The main body has surface communication holes, and the surface communication holes are impregnated with an ionic liquid, and the impregnation ratio expressed as the volume of the ionic liquid with respect to the entire volume of the cage main body including the surface communication holes is 20 % Or more and less than 50%.

ここで、Ｍ_１およびＭ_２は、それぞれ炭化水素基であり、Ｍ_１とＭ_２とは、同一であっても異なっていてもよい。Ｘ^-はアニオンである。 The ionic liquid has an imidazolium cation structure represented by the following formula (1).

Here, M ₁ and M ₂ are each a hydrocarbon group, and M ₁ and M ₂ may be the same or different. X ⁻ is an anion.

In the imidazolium cation structure, M ₁ is an n-octyl group or n-hexyl group, and M ₂ is a methyl group.

  The synthetic resin composition is characterized in that a polyether ether ketone resin is blended with carbon fibers. Further, the cage is a cage used for a rolling bearing that does not enclose a lubricant other than the ionic liquid.

  The surface communication hole of the cage body is formed of a synthetic resin composition containing a pore-forming material to form a molded body, and then a solvent that dissolves the pore-forming material and does not dissolve the synthetic resin composition. It is the hole obtained by extracting the said pore formation material from the said molded object, and using it.

  The rolling bearing of the present invention is a rolling bearing comprising an inner ring and an outer ring, a plurality of rolling elements interposed between the inner and outer rings, and a cage that holds the rolling elements, and the cage is the present invention. It is characterized by being a rolling bearing retainer.

  The cage for a rolling bearing according to the present invention is obtained by impregnating a cage body having a surface communication hole with an ionic liquid at an impregnation rate of 20% or more and less than 50%. By using a vessel, operation can be performed without enclosing grease or the like. For this reason, there is no stirring resistance like a grease-filled bearing, and it can be a low torque bearing. In addition, the use of an ionic liquid reduces the corrosiveness to bearing steel compared to the case where fluorine oil is used, is excellent in heat deterioration resistance, and the impregnation rate is more than 20% and less than 50%. The rolling bearing using is excellent in bearing life at a high temperature such as 150 ° C. or higher.

  In particular, by using a liquid having a predetermined imidazolium cation structure as the ionic liquid to be impregnated, the heat deterioration resistance and lubricity (low friction) are further improved. In addition, by adopting a molded body of a synthetic resin composition in which carbon fiber is blended with polyetheretherketone resin as a cage body, it has excellent mechanical strength and has a high communication porosity to ensure the above impregnation rate. Even in this case, cages of various shapes can be formed, and deformation and breakage during use can be prevented.

  The rolling bearing of the present invention incorporates the above cage, has an excellent bearing life at a high temperature, and has a low torque. Therefore, the rolling bearing can be applied to applications requiring high-temperature high-speed rotation and low torque. Moreover, it is excellent in low dust generation and can be applied to vacuum applications. As a result, the rolling bearing of the present invention can be used for various applications such as industrial equipment used in the semiconductor manufacturing process.

It is a partial expansion perspective view of the crown type cage which is an example of the cage for rolling bearings of the present invention. It is a perspective view of the machined cage which is another example of the cage for rolling bearings of this invention. It is an assembly perspective view of the snap type retainer which is other examples of the cage for rolling bearings of the present invention. It is sectional drawing of the deep groove ball bearing (a crown type cage is used) which is an example of the rolling bearing of this invention.

  The cage for rolling bearings of the present invention includes a cage body that is a molded body of a synthetic resin composition, the cage body has surface communication holes, and the surface communication holes are impregnated with an ionic liquid. Here, the “surface communication hole” is a space structure portion that is composed of mutually continuous holes and communicates with the surface of the cage body. If the cage body is a porous body having such a surface communication hole structure, the inside of the cage body can be impregnated with an ionic liquid without causing an unintentional decrease in strength.

  In the rolling bearing cage of the present invention, the impregnation rate of the ionic liquid is 20% or more and less than 50%. The impregnation rate of the ionic liquid is a ratio in which the volume of the impregnated ionic liquid occupies the entire volume (including the surface communication hole portion) of the cage body. Further, the surface communication porosity of the cage body is composed of mutually continuous holes, and the volume of the space structure portion communicating to the cage body surface, that is, the volume of the surface communication hole is the entire volume of the cage body. It is a ratio of the total (including the surface communication hole portion). For this reason, when the surface communication hole of the cage body is completely impregnated with the ionic liquid, the impregnation rate of the ionic liquid and the surface communication hole rate of the cage body are substantially the same.

  When the impregnation rate of the ionic liquid is less than 20%, the bearing life may be shortened at high temperature and high speed rotation. This is because the viscosity of the ionic liquid is reduced, the ionic liquid is quickly scattered from the site requiring lubrication due to centrifugal force, and the absolute amount of the ionic liquid that can be exuded is insufficient. In addition, when the impregnation rate of the ionic liquid is 50% or more, the surface communication porosity of the cage body is also 50% or more, and the mechanical strength and elastic modulus are greatly reduced. The cage is deformed by force, the cage and the outer ring come into contact with each other, the cage may be broken, and the wear amount may be abnormally increased. The impregnation rate of the ionic liquid is preferably 23 to 45%, more preferably 25 to 40%, and still more preferably 30 to 40%.

An ionic liquid is a substance that becomes a liquid near room temperature in spite of being an ion-binding compound composed of a cation component and an anion component. As the ionic liquid used in the present invention, one having an imidazolium cation structure represented by the following formula (1) in the cation component is preferable because of excellent heat resistance and lubricity.

In the above formula (1), M ₁ and M ₂ are each a hydrocarbon group, and M ₁ and M ₂ may be the same or different. The specific structure is not particularly limited as long as it has excellent heat resistance and lubricity and does not corrode bearing structural materials (such as bearing steel). As said hydrocarbon group, a C1-C12 alkyl group or an alkoxy group is mentioned, for example, C1-C8 is more preferable for torque reduction. Moreover, the alkyl group which has an ether group, ester group, a nitrile group, etc. may be sufficient.

Also, the anion component (X ⁻ ) can be used without particular limitation as long as it is excellent in heat deterioration resistance and lubricity and does not corrode the bearing structural material (bearing steel or the like), like the cation component. Examples of the anion component (X ⁻ ) include halide ions such as Cl ⁻ , SCN ⁻ , BF ₄ ⁻ , ClO ₄ ⁻ , PF ₆ ⁻ , (CF ₃ SO ₂ ) ₂ N ⁻ , and (CF ₃ CF ₂ SO ₂ ) ₂ N ⁻ , CF ₃ SO ₃ ⁻ , CF ₃ COO ⁻ , Ph ₄ B ⁻ , (CF ₃ SO ₂ ) ₃ C ⁻ , PF ₃ (C ₂ F ₅ ) ₃ ^{— and the} like.

Among these, the ionic liquid suitable in the present invention is a case where M ₁ is an n-octyl group or n-hexyl group and M ₂ is a methyl group. Among these, those in which M ₁ is an n-octyl group are particularly preferable. Specific examples of such ionic liquids include: (1) 1-octyl-3-methylimidazolium-bistrifluoromethylsulfonylimide (“MOI-TFSI”: M ₁ = C ₈ H ₁₇ , M ₂ = CH ₃ , X ⁻ = (CF ₃ SO ₂ ) ₂ N ⁻ ), (2) 1-octyl-3-methylimidazolium-tetrafluoroborate (“MOI-TFB”: M ₁ = C ₈ H ₁₇ , M ₂ = CH ₃ , X ⁻ = BF ₄ ⁻ ), (3) 1-octyl-3-methylimidazolium-hexafluorophosphate (M ₁ = C ₈ H ₁₇ , M ₂ = CH ₃ , X ⁻ = PF ₆ ⁻ ). It is done. As shown in Examples described later, these are low torque and particularly excellent in heat resistance and durability.

The kinetic viscosity of the ionic liquid at 40 ° C. is preferably 0.5 to 150 mm ² / sec or less. If it exceeds 150 mm ² / sec, there is a risk that low torque cannot be achieved due to viscous resistance. On the other hand, if it is less than 0.5 mm ² / sec, the bearing life may be shortened due to scattering. Further, the evaporation loss increases, making it difficult to use in a vacuum environment where low dust generation is required.

  In this invention, an ionic liquid may be used individually by 1 type, or multiple types may be mixed and used for it. Moreover, you may mix | blend a corrosion inhibitor, antioxidant, extreme pressure agent, a viscosity index improver, etc. with an ionic liquid as needed in the range which does not impair the objective of this invention before impregnation.

  The synthetic resin composition constituting the cage body can be injection-molded, has sufficient heat resistance, mechanical strength, and elastic modulus as a cage, and has chemical resistance to the ionic liquid to be impregnated. That's fine. Examples thereof include those based on polyether ether ketone (PEEK) resin, polyphenylene sulfide (PPS) resin, thermoplastic polyimide resin, polyamideimide resin, polyamide (PA) 66 resin, polyamide (PA) 46 resin and the like. . These may be used alone or in combination as a polymer alloy.

  The manufacturing method of the cage body having the surface communication hole is not particularly limited, but it is easy to ensure the surface communication hole ratio that can achieve the above-described impregnation rate (20% or more and less than 50%) of the ionic liquid. It is preferable to use the following extraction method using a salt (pore forming material) soluble in water or a solvent. That is, after molding a synthetic resin composition containing a pore-forming material into a molded body, the pore-forming material is dissolved from the molded body using a solvent that dissolves the pore-forming material and does not dissolve the synthetic resin composition. It is obtained by extracting. For example, a water-soluble powder B having a melting point Y ° C. higher than X ° C. is blended with a resin A having a molding temperature X ° C., and molded at X ° C. to form a molded body. By washing and extracting with water or the like, a porous cage body in which surface communication holes are formed in the portion filled with the pore forming material is obtained.

  As a molding method, it is preferable to employ injection molding in terms of excellent manufacturing efficiency, but extrusion molding, heat compression molding, or the like can also be employed. Any known injection molding method and injection molding machine can be used. Moreover, it is good also as a target shape by machining after shaping | molding. Moreover, you may employ | adopt processes, such as an annealing process, for the physical property improvement with respect to the holder | retainer which is a molded article.

  As a method for impregnating the cage body with the ionic liquid, any method may be used as long as it is appropriately impregnated. For example, a vacuum impregnation method may be mentioned. The cage main body is put into an ionic liquid that has been heated to reduce the viscosity, and the inside of the surface communication hole of the cage can be impregnated with the ionic liquid by creating a vacuum environment.

  The pore-forming material used in the case of adopting the extraction method has a melting point higher than the molding temperature of the resin, and is molded with a solvent that does not dissolve the resin after blended with the resin to form a molded body. Any substance that can be dissolved and extracted from the body can be used. A water-soluble substance is preferable because the washing and extraction process becomes easy. In addition, the pore-forming material may remain during extraction, and may fall off during use. By using an alkaline substance (particularly a water-soluble weak alkali salt) that can act as a corrosion inhibitor as the pore forming material, it is possible to prevent corrosion of the bearing structure material (bearing steel, etc.) due to the ionic liquid at the time of dropping. Examples of such pore forming material include sodium tripolyphosphate, sodium sebacate, sodium benzoate, sodium acetate and the like. Further, the pore forming material is preferably controlled to have an average particle size of 1 to 500 μm.

  In addition, the pore forming material serving as a corrosion inhibitor may be partly extracted so as to be partly left in the surface communication hole of the cage body, and the surface communication hole may be impregnated with an ionic liquid. Thereby, an ionic liquid can be impregnated in the form containing a corrosion inhibitor in the surface communication hole.

  The blending amount of the pore-forming material is set such that the surface communication porosity is 20% or more and less than 50% in order to achieve the above-described impregnation rate (20% or more and less than 50%) of the ionic liquid. Specifically, it is preferable to blend 30% by volume or more with respect to the entire synthetic resin composition. If it is less than 30% by volume, the pore-forming material that does not become surface communication holes and remains independently inside the resin increases, and the surface communication porosity of 20% may not be obtained. In addition, when the amount of the pore-forming material is 35% by volume or more, almost complete extraction is possible, and surface communication holes corresponding to the amount of the amount can be obtained.

  In the synthetic resin composition constituting the cage body, fillers and additives such as reinforcing fibers may be blended for the purpose of increasing the mechanical strength and elastic modulus and improving the heat deterioration resistance. Examples of reinforcing fibers include PAN-based carbon fibers, pitch-based carbon fibers, glass fibers, aramid fibers, whiskers, etc., and additives include solid lubricants, antioxidants, plasticizers, colorants, release agents. Examples include molds.

  Moreover, the compounding quantity of a reinforced fiber is 2-30 volume% with respect to the whole synthetic resin composition, Preferably it is 2-20 volume%, More preferably, it is 5-15 volume%. In addition, when using an extraction method, this is the compounding quantity with respect to the whole synthetic resin composition including a pore formation material, and the ratio of the reinforced fiber with respect to the resin base material of the cage main body after manufacture becomes a higher range. When the amount of the reinforcing fiber is less than 5% by volume, sufficient strength or elastic modulus may not be improved. When it exceeds 30% by volume, when molding a crown type cage or the like, There is a risk that it will not be able to cope with forcible removal, and the cage pocket surface and the claw will crack and whiten.

  As an example of the rolling bearing cage of the present invention, a crown type rolling bearing cage will be described with reference to FIG. FIG. 1 shows a partially enlarged perspective view of a crown type cage. As shown in FIG. 1, the cage 1 forms a pair of opposed holding claws 3 on the upper surface of the annular main body 2 at a constant pitch in the circumferential direction, and the opposed holding claws 3 approach each other. A rolling element holding pocket 4 for holding a ball as a rolling element is formed between the holding claws 3 while bending. Further, a flat portion 5 serving as a rising reference surface for the holding claws 3 is formed between the back surfaces of the holding claws 3 adjacent to each other in the adjacent pockets 4. The holding claw 3 has a bent tip portion 3a. When the extraction method is adopted, the pore forming material remains in the molded body at the time of die cutting after injection molding, and cracking and whitening can be prevented when the cage nails are forcibly removed.

  As another example of the rolling bearing cage of the present invention, a machined type rolling bearing cage will be described with reference to FIG. FIG. 2 shows a perspective view of a machined cage obtained by cutting after molding a shaped material using the synthetic resin composition. As shown in FIG. 2, the cage 1 is provided with a plurality of rolling element holding pockets 7 holding a ball as a rolling element at a constant interval in an annular main body 6. The planar shape of the pocket 7 is a flat circular shape, but may be a perfect circle.

  As another example of the rolling bearing cage of the present invention, a snap-type rolling bearing cage will be described with reference to FIG. FIG. 3 is an assembled perspective view of a snap-type cage obtained by injection molding the synthetic resin composition. The cage 1 is obtained by engaging two annular bodies 8. The annular body 8 includes a plurality of hemispherical rolling element holding portions 10 and a plurality of plate-like coupling portions 9. The rolling body holding portions 10 and the coupling portions 9 are alternately formed in the circumferential direction, and A pocket 11 that opens on one side of the annular body 8 is provided in the moving body holding unit 10. The inner surface of the pocket 11 is a hemispherical surface along the outer periphery of the ball. The coupling portion 9 is formed with an engagement hole 9a penetrating both side surfaces and an engagement claw 9b inserted into the engagement hole 9a of the other annular body, and is engaged with the inner periphery of the engagement hole 9a. A step 9c is provided. On the other hand, a hook 9d that can be engaged with the engaging step 9c is formed at the tip of the engaging claw 9b, and the end surface of the hook 9d in the circumferential direction of the cage is an inclined surface.

  The present invention can be applied to any of the above-described rolling bearing cages. When the surface porosity and impregnation rate are high (for example, 35% or more), it is easy to suppress deformation due to centrifugal force etc. It is good also as a vessel.

  An example of the rolling bearing of the present invention will be described with reference to FIG. FIG. 4 is a cross-sectional view of a rolling bearing using the rolling bearing cage (crown cage) of the present invention. In the rolling bearing 12, an inner ring 13 having a rolling surface 13a on the outer peripheral surface and an outer ring 14 having a rolling surface 14a on the inner peripheral surface are arranged concentrically. A plurality of rolling elements 15 are disposed between the rolling surface 13a of the inner ring and the rolling surface 14a of the outer ring. The plurality of rolling elements 15 are held by the cage 1 of the present invention. The rolling bearing 12 does not enclose a lubricant such as grease other than the ionic liquid impregnated in the cage 1, and is lubricated by the ionic liquid supplied from the cage 1.

  If necessary, a small amount of grease may be enclosed as long as low torque can be maintained. In addition, the rolling bearing of the present invention may be any type such as a ball bearing, a tapered roller bearing, a self-aligning roller bearing, or a needle roller bearing.

  Hereinafter, the present invention will be further described with reference to examples and comparative examples, but the present invention is not limited thereto.

Examples 1 to 10 and Comparative Examples 1 to 5
The resin base material, carbon fiber, and pore forming material were melt kneaded with a Brabender with the compositions (volume ratios) shown in Table 1 and Table 2, and then pulverized to obtain a mixed powder. Using this, a crown type cage for a ball bearing (nominal number 6204, outer diameter 47 mm, inner diameter 20 mm, width 14 mm) was obtained by injection molding. The injection molded body was washed with warm water at 100 ° C. for 100 hours to elute the pore forming material. Thereafter, drying was performed at 100 ° C. for 3 hours to obtain a cage having surface communication holes. The surface communication holes of this cage were vacuum impregnated with ionic liquids or oils shown in Tables 1 and 2 at 200 ° C. The impregnation rate is as shown in each table.

  The obtained cage was incorporated into a ball bearing (nominal number 6204, outer diameter 47 mm, inner diameter 20 mm, width 14 mm) to obtain a test bearing, which was subjected to the following bearing life test and bearing torque test. The results are shown in Tables 1 and 2. In addition, grease etc. are not enclosed in the test bearing.

Comparative Example 6
A crown type cage for a ball bearing (nominal number 6204T2ZZ, an outer diameter of 47 mm, an inner diameter of 20 mm, and a width of 14 mm) was obtained by injection molding using a resin material in which 25% by weight of glass fiber was blended with BioPA66. The obtained cage was assembled in a ball bearing (nominal number 6204T2ZZ), and grease shown in Table 2 was sealed to obtain a test bearing. The test bearing was subjected to the following bearing life test and bearing torque test in the same manner as in Example 1.

<Bearing life test>
The test bearing was rotated at an axial load of 67 N and a radial load of 67 N at a bearing temperature of 150 ° C. and a rotational speed of 10,000 rpm, and the time until seizure was measured as the bearing test life (h).

<Bearing torque test>
The test bearing is fixed to the static pressure gas bearing so that it is a vertical type, the rotational speed is 5000 rpm, the room temperature (25 ° C.) atmosphere, the axial load is 39.2 N, and 15 minutes after the start of operation when the inner ring is rotated, The average value of the generated rotational torque was calculated. The average value of the calculated rotational torque was evaluated in two stages as follows.
“O” mark: Rotational torque less than 5 × 10 ⁻² Nm “X” mark: Rotational torque greater than 5 × 10 ⁻² Nm

<Comprehensive evaluation>
If the bearing life test is 200 hours or more and the bearing torque test is marked with “○”, the bearing life test and the bearing torque test are evaluated as “○” as a long-life and low-torque bearing. The value below the specified value was expressed as comprehensive evaluation “x”.

  As shown in Table 1, it can be seen that the rolling bearing incorporating the porous resin cage impregnated with the ionic liquid of each example exhibits a low torque while ensuring a high temperature life.

  The rolling bearing of the present invention has excellent bearing life at high temperatures and low torque, and therefore can be suitably used for various applications such as industrial equipment used in semiconductor manufacturing processes.

DESCRIPTION OF SYMBOLS 1 Cage 2 Main body 3 Holding claw 4 Rolling body holding pocket 5 Flat part 6 Main body 7 Rolling body holding pocket 8 Annular body 9 Coupling part 10 Rolling body holding part 11 Pocket 12 Rolling bearing 13 Inner ring 14 Outer ring 15 Rolling body

Claims (7)

A rolling bearing cage for holding rolling elements of a rolling bearing,
The cage includes a cage body that is a molded body of a synthetic resin composition, the cage body has a surface communication hole, and the surface communication hole is impregnated with an ionic liquid;
The rolling bearing retainer, wherein an impregnation ratio expressed as a volume of the ionic liquid with respect to a total volume of the retainer main body including the surface communication hole portion is 20% or more and less than 50%. The rolling bearing retainer according to claim 1, wherein the ionic liquid has an imidazolium cation structure represented by the following formula (1).

Here, M ₁ and M ₂ are each a hydrocarbon group, and M ₁ and M ₂ may be the same or different. X ⁻ is an anion. The cage for a rolling bearing according to claim 2, wherein, in the imidazolium cation structure, M ₁ is an n-octyl group or n-hexyl group, and M ₂ is a methyl group.   4. The rolling bearing retainer according to claim 1, wherein the synthetic resin composition is formed by blending carbon fiber with a polyether ether ketone resin.   The rolling bearing retainer according to any one of claims 1 to 4, wherein the retainer is a retainer used for a rolling bearing that does not enclose a lubricant other than the ionic liquid.   The surface communication hole of the cage body is formed by molding a synthetic resin composition containing a pore-forming material into a molded body, and then dissolving the pore-forming material and not dissolving the synthetic resin composition. The rolling bearing retainer according to any one of claims 1 to 5, wherein the retainer is a hole obtained by extracting the pore forming material from the molded body. A rolling bearing comprising an inner ring and an outer ring, a plurality of rolling elements interposed between the inner and outer rings, and a cage for holding the rolling elements,
The rolling bearing according to any one of claims 1 to 6, wherein the cage is a rolling bearing cage.

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