JP4541769B2 - Roller bearing cage and rolling bearing - Google Patents

Description

  The present invention relates to a rolling bearing cage and a rolling bearing using the cage, and more particularly to a bearing cage used under vacuum conditions and a rolling bearing using the cage.

Normally, a lubricant is held inside the rolling bearing for the purpose of reducing the friction coefficient between the inner and outer rings, the rolling elements and the cage, and improving the durability of the bearing. As the lubricant, a liquid lubricant, a semi-solid lubricant, a solid lubricant, or the like is appropriately used depending on the application. For example, in a vacuum rolling bearing used in a clean atmosphere such as a semiconductor manufacturing facility, particularly in a low-pressure clean atmosphere such as a vacuum, steam generated from the above-described liquid lubricant and semi-solid lubricant, Since the scattered fine particles may adversely affect the performance of precision parts, low vapor pressure liquid lubricants and solid lubricants are used. In recent years, with the improvement in performance of precision parts such as semiconductors whose line widths of conductive patterns are extremely fine, extremely high low dust generation is required.
Conventionally, as a rolling bearing for vacuum that relatively well meets the above requirements for low dust generation, a low vapor pressure fluorinated oil is used as the lubricating oil, and the fluorinated oil is made of a polyamideimide resin porous body. And the like, which are impregnated in a cage made of (see Patent Document 1), and those in which a porous polyimide cage superior in heat resistance to polyamideimide is impregnated with the fluorinated oil (see Patent Document 2). In addition, a rolling bearing (see Patent Document 3) in which an alkylated cyclopentane oil is used as a lubricating oil and impregnated in a cage made of a porous material is also disclosed.

However, in the rolling bearings of Patent Document 1 and Patent Document 2, when the porous cage is impregnated with fluorinated oil as the lubricating oil, the centrifugal force applied to the cage during rotation increases, and the rotational efficiency of the bearing decreases. There is a problem that torque fluctuations also increase. In addition, this conventional rolling bearing cannot be said to be sufficiently reliable in terms of durability under use conditions at a high surface pressure (about 2 GPa).
In the bearing of Patent Document 3, although the above-mentioned problem of the bearing using fluorinated oil has been solved, the continuous ventilation hole of the cage is 5 to 25%, so that the amount of lubricating oil that can be impregnated is small and the service life is sufficient. There is a problem that it is not possible to plan for a long extension.
Japanese Patent Laid-Open No. 61-6429 JP-A-8-177866 JP-A-10-169661

  The present invention has been made to cope with such problems, and even when used under vacuum conditions, it does not generate a gas derived from lubricating oil, has low dust generation, and can be used for a long time with an increased oil content. An object is to provide a cage and a rolling bearing using the cage.

The bearing cage of the present invention is a rolling bearing cage comprising a molded body of a synthetic resin composition that holds a rolling element of a rolling bearing, and the molded body is a resin having a communication porosity of 30% or more. It is characterized by impregnating a porous body with a lubricating oil having a vapor pressure at 40 ° C. of 1.0 × 10 ⁻⁵ Pa or less.
The lubricating oil is an alkylated cyclopentane oil.
The lubricating oil is perfluoropolyether oil.

The resin porous body is formed by molding a resin containing at least one pore forming material selected from an organic alkali metal salt and an organic alkaline earth metal salt, and then dissolving the pore forming material. And it has the communicating hole obtained by extracting the said pore formation material from the said molded object using the solvent which does not melt | dissolve the said resin, It is characterized by the above-mentioned.

The rolling bearing of the present invention is a concentric arrangement of an inner ring having a rolling surface on the outer peripheral surface and an outer ring having a rolling surface on the inner peripheral surface, and a plurality of rolling elements interposed between the both rolling surfaces; A rolling bearing provided with a cage that holds the plurality of rolling elements, wherein the cage is the cage of the present invention.
Also, a grease-filled rolling bearing in which lubricating grease is enclosed around the plurality of rolling elements, wherein the base oil of the lubricating grease has a vapor pressure at 40 ° C. of 1.0 × 10 ⁻⁵ Pa or less. And

The cage for a rolling bearing of the present invention is formed by impregnating a porous resin body having a communication porosity of 30% or more with a lubricating oil having a vapor pressure at 40 ° C. of 1.0 × 10 ⁻⁵ Pa or less. The used rolling bearing has excellent low dust generation property without evaporation of the lubricating oil even under vacuum conditions (10 ⁻⁴ Pa), and has excellent durability and can be used for a long time.
In addition, the rolling bearing of the present invention in which the lubricating grease is enclosed has a vapor pressure at 40 ° C. of the base oil of the lubricating grease of 1.0 × 10 ⁻⁵ Pa or less. In addition to having excellent low dust generation, it has excellent durability and can be used for a long time.

式中、Ｒは直鎖状または分岐状のアルキル基であり、ｍは 3 〜 4 の整数である。
上記アルキル化シクロペンタン系油の具体例としては、トリ（２−オクチルドデシル）シクロペンタン（蒸気圧（ 40 ℃）：1.0 ×10^-8 Pa ＮＹＥ ＬＵＢＩＣＡＮＴＳ社製ＮＹＥ ＳＹＮＴＨＥＴＩＣ ＯＩＬ ２００１Ａ）が挙げられる。 As the lubricating oil impregnated in the cage of the present invention, any lubricating oil having a vapor pressure at 40 ° C. of 1.0 × 10 ⁻⁵ Pa or less can be used. When the vapor pressure of the lubricating oil at 40 ° C. is 1.0 × 10 ⁻⁵ Pa or less, the lubricating oil can be prevented from divergence in a vacuum and can be used under vacuum conditions.
Examples of the lubricating oil include petroleum-based lubricating oil, alkylated cyclopentane-based oil, and perfluoropolyether oil that have been highly refined so as to have the low vapor pressure.
An alkylated cyclopentane oil is preferably used because it is a lubricating oil that can sufficiently withstand use under vacuum conditions and has excellent heat resistance, chemical resistance, solvent resistance, load resistance, and the like. Further, when the surface pressure applied to the rolling surface is low, perfluoropolyether oil can be suitably used.
The alkylated cyclopentane oil is a lubricating oil having a structure shown in Chemical Formula 1 below.

In the formula, R is a linear or branched alkyl group, and m is an integer of 3 to 4.
Specific examples of the alkylated cyclopentane oil include tri (2-octyldodecyl) cyclopentane (vapor pressure (40 ° C.): 1.0 × 10 ⁻⁸ Pa NYE SYNTHETIC OIL 2001A manufactured by NYE LUBICANTS).

As the perfluoropolyether oil, either a linear type or a branched type can be used as long as the above vapor pressure condition is satisfied. Specific examples of perfluoropolyether oil include demnum S-200 (vapor pressure (40 ° C.): 1.0 × 10 ⁻⁶ Pa made by Daikin Industries), Fomblin YHVAC 140/13 (vapor pressure (40 ° C.): 1.0 × 10 ⁻⁹ Pa Solvay Solexis), Fomblin Z25 (Vapor Pressure (40 ° C.): 1.0 × 10 ⁻⁹ Pa Solvay Solexis), Fomblin Z60 (Vapor Pressure (40 ° C.): 1.0 × 10 ^{− 11} Pa Solvay Solexis), Krytox 143AC (vapor pressure (40 ° C.): 1.0 × 10 ⁻⁵ Pa DuPont), Krytox 143AD (vapor pressure (40 ° C.): 8.0 × 10 ⁻⁷ Pa DuPont And Crytox L220 (vapor pressure (40 ° C.): 6.0 × 10 ⁻⁸ Pa manufactured by DuPont).

The lubricating oil may be used alone or in combination as long as it satisfies the vapor pressure condition.
Moreover, in the above-mentioned lubricating oil, as long as it does not impair the purpose of the present invention, an extreme pressure agent, an antioxidant, a rust inhibitor, a pour point depressant, an ashless dispersant, a metal detergent, Surfactants, wear modifiers, etc. can be blended. As the antioxidant, phenol, amine, sulfur and the like can be used alone or in combination.

Face-centered cubic lattice and hexagonal close-packed packing are the most densely packed spheres by point contact, and their filling ratio is (volume of sphere ÷ volume of circumscribed cube) ÷ (height of equilateral triangle ÷ base) ÷ (Height of regular tetrahedron ÷ one side) and both are 74%. The porosity defined as (100-filling factor) is 26%.
The above calculation is a case where spheres of the same size are considered. However, when spheres of a plurality of sizes are filled, the filling rate becomes larger than the hexagonal close-packed filling, and the porosity becomes smaller.
Further, when the powdered spherical resin particles are sintered after compression molding, there is no point contact, and the spherical resin particles are deformed and brought into surface contact. For this reason, a filling rate becomes larger than a hexagonal close-packing, and a porosity becomes smaller. For this reason, the porosity of conventional sintered resin moldings is limited to about 20%.

上記、数１において、各符号の意味を以下に示す。
Ｖ；加熱圧縮成形法にて成形された洗浄前成形体の体積
ρ；加熱圧縮成形法にて成形された洗浄前成形体の密度
Ｗ；加熱圧縮成形法にて成形された洗浄前成形体の重量
Ｖ₁；樹脂粉末の体積
ρ₁；樹脂粉末の密度
Ｗ₁；樹脂粉末の重量
Ｖ₂；気孔形成材の体積
ρ₂；気孔形成材の密度
Ｗ₂；気孔形成材の重量
Ｖ₃；洗浄後の多孔体の体積
Ｗ₃；洗浄後の多孔体の重量
Ｖ’₂；洗浄後に多孔体に残存する気孔形成材の体積 The communication porosity in the present invention is the same definition as the above porosity, and refers to the porosity in a state where the pores are continuous. That is, it refers to the ratio of the total volume of pores that are continuous to the resin molded body.
Specifically, the communication porosity was calculated by the method shown in Equation (1) in Equation 1.

In the above Equation 1, the meaning of each symbol is shown below.
V: Volume ρ of the pre-cleaning molded body formed by the heat compression molding method; density W of the pre-cleaning molded body molded by the heat compression molding method; Weight V ₁ ; Volume ρ _{1 of} resin powder; Density W _{1 of} resin powder; Weight V _{2 of} resin powder; Volume ρ _{2 of} pore forming material; Density W _{2 of} pore forming material; Weight V _{3 of} pore forming material; Washing The volume W ₃ of the porous body after; the weight V ′ ₂ of the porous body after cleaning; the volume of the pore forming material remaining in the porous body after cleaning

  In the present invention, a porous resin body of a synthetic resin composition having a communicating porosity of 30% or more, preferably 30% to 90%, more preferably 30 to 70% is obtained by the production method described below.

  The resin porous body that can be used in the present invention is obtained by molding a resin containing a pore-forming material into a molded body, then dissolving the pore-forming material and using a solvent that does not dissolve the resin from the molded body. It is obtained by extracting the forming material. 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. Is extracted with water to obtain a porous body.

As resin which can be used for this invention, resin powder and pellets, such as a thermoplastic resin, a thermosetting resin, an elastomer, or rubber | gum, can be used. The particle size and shape of the resin powder and pellets are not particularly limited when melt molding because they are kneaded with the pore forming material at the time of melting. In the case of dry blending and compression molding as it is, an average particle size of 1 to 500 μm is preferable.
Examples of the thermoplastic resin or thermosetting resin include polyethylene resins such as low density polyethylene, high density polyethylene, and ultrahigh molecular weight polyethylene, modified polyethylene resins, water-crosslinked polyolefin resins, polyamide resins, aromatic polyamide resins, polystyrene resins, Polypropylene resin, silicone resin, urethane resin, polytetrafluoroethylene resin, chlorotrifluoroethylene resin, tetrafluoroethylene / hexafluoropropylene copolymer resin, tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer resin, vinylidene fluoride resin , Ethylene / tetrafluoroethylene copolymer resin, polyacetal resin, polyethylene terephthalate resin, polybutylene terephthalate resin, polyphenylene ether resin, Recarbonate resin, aliphatic polyketone resin, polyvinylpyrrolidone resin, polyoxazoline resin, polyphenylene sulfide resin, polyethersulfone resin, polyetherimide resin, polyamideimide resin, polyetheretherketone resin, thermoplastic polyimide resin, thermosetting Examples thereof include a functional polyimide resin, an epoxy resin, a phenol resin, an unsaturated polyester resin, and a vinyl ester resin. Moreover, the mixture of 2 or more types of materials chosen from the said synthetic resin, ie, a polymer alloy, etc. can be illustrated.

  The rolling bearing of the present invention is mainly used under a vacuum condition, and the heat conductivity is lower than that in the air under the vacuum condition. There are many. Accordingly, among the resins listed above, polytetrafluoroethylene resin, polyether ether ketone resin, polyimide resin, and the like are particularly preferable.

  Examples of the elastomer or rubber include acrylonitrile butadiene rubber, isoprene rubber, styrene rubber, butadiene rubber, nitrile rubber, chloroprene rubber, butyl rubber, acrylic rubber, silicone rubber, fluorine rubber, ethylene propylene rubber, chlorosulfonated polyethylene rubber, chlorinated Examples thereof include vulcanized rubbers such as polyethylene rubber and epichlorohydrin rubber; and thermoplastic elastomers such as polyurethane elastomer, polyester elastomer, polyamide elastomer, polybutadiene elastomer, and soft nylon elastomer.

The pore-forming material is a substance that has a melting point higher than the molding temperature of the resin and can be extracted by being dissolved from the molded body using a solvent that does not dissolve the resin after being blended with the resin to form a molded body. You can use it if you want.
The pore forming material is preferably a water-soluble substance that facilitates the washing and extracting process. Further, an alkaline substance, preferably a weak alkaline substance that can be used as a rust preventive is preferred. Examples of the weak alkali salt include organic alkali metal salts, organic alkaline earth metal salts, inorganic alkali metal salts, inorganic alkaline earth metal salts, and the like. It is preferable to use an organic alkali metal salt or an organic alkaline earth metal salt because even when the unextracted component falls off, it is relatively soft and hardly damages the rolling surface and the sliding surface. In addition, you may use these metal salts 1 type or in mixture of 2 or more types. In addition, it is preferable to use a water-soluble weak alkali salt because inexpensive water can be used as a cleaning solvent, and waste liquid treatment at the time of pore formation is facilitated.
In order to prevent dissolution of the pore forming material during molding, the pore forming material uses a substance having a melting point higher than the molding temperature of the resin used.
Examples of water-soluble organic alkali metal salts that can be suitably used in the present invention include sodium benzoate (melting point: 430 ° C.), sodium acetate (melting point: 320 ° C.) or sodium sebacate (melting point: 340 ° C.), sodium succinate, and stearic acid. Sodium etc. are mentioned. Sodium benzoate, sodium acetate, or sodium sebacate is particularly preferred because of its high melting point, compatibility with various resins, and high water solubility.
Examples of the inorganic alkali metal salt include potassium carbonate, sodium molybdate, potassium molybdate, and sodium tungstate.

The pore forming material manages the average particle size according to the use of the resin porous body. When used as a rolling bearing cage, a pore forming material having an average particle size of 1 to 500 μm is preferable.
The ratio of the pore forming material is 30% by volume to 90% by volume, preferably 40% by volume to 90% by volume, with respect to the total amount including other materials such as resin powder, porous body forming material and filler. If it is 30% by volume or less, the pores of the porous body are hardly formed into continuous pores, and if it is 90% by volume or more, desired mechanical strength cannot be obtained.
Moreover, you may mix | blend the filler insoluble in the solvent used for extraction of a pore formation material at the time of a mixing | blending. For example, when the solvent is water, glass fibers, carbon fibers, and the like can be blended for the purpose of improving the mechanical strength of the porous body.

The mixing method of the resin material and the pore forming material is not particularly limited, and a kneading method generally used for mixing the resin such as dry blending and melt kneading can be applied.
Alternatively, a method may be used in which the pore-forming material is dissolved in a liquid solvent to form a transparent solution, and then resin powder is dispersed and mixed in the solution, and then the solvent is removed.
The method of dispersing and mixing is not particularly limited as long as it can be mixed in a liquid, and examples thereof include a ball mill, an ultrasonic disperser, a homogenizer, a juicer mixer, and a Henschel mixer. It is also effective to add a small amount of a surfactant in order to suppress separation of the dispersion. At the time of mixing, the amount of solvent is secured so that the pore forming material is completely dissolved by mixing.
As a method for removing the solvent, methods such as heat evaporation, vacuum evaporation, bubbling with nitrogen gas, dialysis, and freeze-drying can be used. Since the method is easy and the equipment is inexpensive, it is preferable to remove the liquid solvent by heat evaporation.
For molding a mixture in which a pore molding material is blended with a resin, any molding method such as compression molding, injection molding, extrusion molding, blow molding, vacuum molding, transfer molding or the like can be employed. Moreover, in order to improve workability | operativity before shaping | molding, you may process into a pellet, a prepreg, etc.

Extraction of the pore-forming material from the obtained molded body is performed by washing the molded body with a solvent that dissolves the pore-forming material and does not dissolve the resin.
As the solvent, for example, water and alcohol solvents, ester solvents, ketone solvents, and the like can be used as solvents compatible with water. Among these, it is appropriately selected according to the above conditions depending on the type of resin and pore forming material. These solvents may be used alone or in combination of two or more. It is preferable to use water because of its advantages such as easy waste liquid treatment and low cost.
By performing the extraction treatment, a portion filled with the pore forming material is dissolved, and a resin porous body having pores formed in the dissolved portion is obtained.

  An example of the structure of a rolling bearing cage using the resin porous body is shown in FIG. FIG. 1 is a partially enlarged perspective view of a crown-shaped cage integrally molded with a resin composition. The rolling bearing retainer 1 is formed with a pair of opposing retainer claws 3 on the upper surface of an annular retainer body 2 at a constant pitch in the circumferential direction, and the opposing retainer claws 3 are arranged so as to 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.

A rolling bearing cage 1 shown in FIG. 1 is formed by molding a resin in which the alkaline pore forming material described above is blended to form a molded body of a rolling bearing cage, and then dissolves the included pore forming material. In addition, the above-mentioned vapor pressure at 40 ° C. is 1.0 × 10 ⁻⁵ Pa or less in the resin porous body having a communicating porosity of 30% or more obtained by extracting the pore-forming material using a solvent that does not dissolve the molded body Obtained by impregnating lubricating oil.

An example of a rolling bearing using the cage of the present invention is shown in FIG. FIG. 2 is a cross-sectional view of a grease-filled deep groove ball bearing.
In the grease-filled deep groove ball bearing 6, an inner ring 7 having a rolling surface 7a on the outer peripheral surface and an outer ring 8 having a rolling surface 8a on the inner peripheral surface are arranged concentrically, and the rolling surface 7a of the inner ring and the outer ring roll. A plurality of rolling elements 9 are interposed between the surface 8a. The cage 1 includes a plurality of rolling elements 9 and a seal member 10 fixed to the outer ring 8 or the like. Lubricating grease 11 is enclosed around the rolling elements 9.

As the base oil constituting the lubricating grease, any base oil having a vapor pressure at 40 ° C. of 1.0 × 10 ⁻⁵ Pa or less can be used. For example, what was mentioned as the said lubricating oil can be used.
Thickeners constituting the lubricating grease include aluminum soaps, lithium soaps, sodium soaps, composite lithium soaps, composite calcium soaps, composite aluminum soaps, and other urea, such as diurea compounds and polyurea compounds. System compounds. These thickeners may be used alone or in combination of two or more.
Also known additives added to lubricating grease, for example, extreme pressure agents, amine-based, phenol-based antioxidants, metal deactivators such as benzotriazole, sodium nitrite, viscosity index such as polymethacrylate, polystyrene, etc. Examples include improvers, solid lubricants such as molybdenum disulfide and graphite. These can be added alone or in combination of two or more.

As the base oil of the lubricating grease, it is preferable to use a lubricating oil impregnated in the resin porous body of the cage and an oil that mutually dissolves under the rolling bearing operating environment conditions. The mutually soluble oils are preferably oils having the same chemical structure, and more preferably, the lubricating oil and the base oil are the same type of oil and have substantially the same viscosity. preferable. By using together with this lubricating grease, since the base oil consumed by the lubricating grease is supplied from the lubricating oil impregnated in the cage, the amount of lubricating grease enclosed can be reduced. The amount of lubrication grease enclosed is 20% or less, preferably 5 to 20% of the total space volume of the bearing. If the amount of grease filled exceeds 20%, grease leakage or torque fluctuation may occur easily.
In addition, since the lubricating oil is supplied from the cage by using the rolling bearing cage of the present invention as the cage 1, the bearing 6 can be used without enclosing the lubricating grease 11. In applications where low torque and torque stability are prioritized, it is possible to operate with only the lubricating oil contained in the cage without enclosing lubricating grease.

The rolling bearing having the above-described structure incorporating the cage of the present invention can be suitably used even under the conditions because the lubricating oil impregnated in the cage and the base oil of the lubricating grease do not evaporate under vacuum conditions.
Further, the rolling bearing of the present invention is not limited to a ball bearing, and can be used for a cylindrical roller bearing, a tapered roller bearing, and the like.

Example 1
Polyetheretherketone resin powder (150 PF manufactured by Victrex Co., Ltd.), carbon fiber, and sodium benzoate powder (reagent manufactured by Wako Pure Chemical Industries, Ltd.) are melted by Brabender in a volume ratio of 50:10:40 After kneading, the mixture was pulverized to obtain a mixed powder. Using this mixed powder, a crown type cage for ball bearing # 608 was molded by injection molding. This molded product was washed with warm water at 80 ° C. for 10 hours with an ultrasonic cleaner to elute the sodium benzoate powder. Thereafter, it was dried at 100 ° C. for 8 hours to obtain a porous body having a communication porosity of 40%. This porous material was impregnated with an alkylated cyclopentane oil (NYESYNTHETIC OIL 2001A manufactured by NYE LUBICANTS) at 100 ° C. under vacuum. The oil content was 39% of the total volume, and the oil content was 0.1 g. The cage was assembled in a # 608 bearing (608 model number: outer diameter 22 mm, inner diameter 8 mm, width 7 mm) made of SUS440C.

Example 2
Polyetheretherketone resin powder (150 PF manufactured by Victrex Co., Ltd.), carbon fiber, and sodium benzoate powder (reagent manufactured by Wako Pure Chemical Industries, Ltd.) are melted by Brabender in a volume ratio of 50:10:40 After kneading, the mixture was pulverized to obtain a mixed powder. Using this mixed powder, a crown type cage for ball bearing # 608 was molded by injection molding. This molded product was washed with warm water at 80 ° C. for 10 hours with an ultrasonic cleaner to elute the sodium benzoate powder. Thereafter, it was dried at 100 ° C. for 8 hours to obtain a porous body having a communication porosity of 40%. This porous material was vacuum impregnated with perfluoropolyether oil (N-Demnam S-200, manufactured by Daikin Industries, Ltd.) at 100 ° C. The oil content was 39% of the total volume, and the oil content was 0.18g. The cage was incorporated into a # 608 bearing made of SUS440C.

比較例２
化２で示される繰り返し単位構造のポリイミド樹脂粉末（宇部興産社製：ＵＩＰ−Ｒ、平均粒径 9 μm）を成形圧力 4000 kgf/cm²で成形し、さらに窒素雰囲気下に 400℃で2 時間焼結し、得られた焼結体を切削加工して連通孔率 15 ％の多孔体からなる玉軸受＃６０８用冠型保持器を得た。この保持器にパーフルオロポリエーテル油（ダイキン工業社製ＮデムナムＳ−２００）を100℃にて真空含浸した。含油量は 0.065g であった。該保持器をＳＵＳ４４０Ｃ製の＃６０８軸受に組み込んだ。 Comparative Example 1
Polyimide resin powder (Ube Industries, Ltd .: UIP-R, average particle size 9 μm) having a repeating unit structure represented by the following chemical formula ² is molded at a molding pressure of 4000 kgf / cm ² and further at 400 ° C. in a nitrogen atmosphere. Sintering was performed for 2 hours, and the obtained sintered body was cut to obtain a crown type cage for ball bearing # 608 made of a porous body having a communication porosity of 15%. The cage was vacuum impregnated with alkylated cyclopentane oil (NYESYNTHETIC OIL 2001A manufactured by NYE LUBICANTS) at 100 ° C. The oil content was 0.035 g. The cage was incorporated into a # 608 bearing made of SUS440C.

Comparative Example 2
Polyimide resin powder (Ube Industries, Ltd .: UIP-R, average particle size 9 μm) having the repeating unit structure shown in Chemical Formula ² was molded at a molding pressure of 4000 kgf / cm ² and further at 400 ° C. for 2 hours in a nitrogen atmosphere Sintering was performed, and the obtained sintered body was cut to obtain a crown type cage for a ball bearing # 608 made of a porous body having a communication porosity of 15%. The cage was vacuum impregnated with perfluoropolyether oil (N-Demnum S-200 manufactured by Daikin Industries, Ltd.) at 100 ° C. The oil content was 0.065g. The cage was incorporated into a # 608 bearing made of SUS440C.

The following tests were performed on the bearings of the obtained examples and comparative examples. The results are shown in Table 1.
Dust generation test:
Rotate the bearing obtained under the conditions of room temperature, degree of vacuum (1-10) x ^10-5 Pa, thrust load 9.8N (surface pressure 0.7GPa) or 980N (surface pressure 2.7GPa), rotation speed 50rpm, Using a dust detector (a sensor that uses a laser beam sensor to measure the number of dust) placed directly below, dust of 0.3 μm or more was detected for 150 hours to determine the total number of dust.

Torque fluctuation test:
Torque fluctuation range of bearings obtained under conditions of room temperature, degree of vacuum (1-10) x ^10-5 Pa, rotation speed 200 rpm, thrust load 9.8N (surface pressure 0.7GPa) or 980N (surface pressure 2.7GPa) Was measured. Evaluation is made in two stages: torque fluctuation exceeding 2 × 10 ^-3 N · m, “large” torque fluctuation, and torque fluctuation width of 1 × 10 ^-3 N · m or less, “small” torque fluctuation. Evaluated.

An endurance test:
Vibration width of the bearing obtained under the conditions of room temperature, degree of vacuum (1-10) x ^10-5 Pa, rotation speed 2500 rpm, thrust load 9.8N (surface pressure 0.7GPa) or 980N (surface pressure 2.7GPa) Was measured as the time (h) required until the test time became three times that at the start of the test.

  In Example 1, the dust generation and torque fluctuation were similar to those in Comparative Example 1, but the durability was excellent. This is thought to be due to an increase in the oil content of the cage. Further, Example 2 was excellent in durability when the surface pressure was low.

  The rolling bearing retainer of the present invention and the rolling bearing using the retainer are free from the generation of lubricating oil-derived gas even under vacuum conditions, have low dust generation, and can be used for a long time. It can be suitably used as a basic part such as a device used under conditions or a device used in a clean room.

FIG. 3 is a partially enlarged perspective view of a crown type cage integrally molded with a resin composition. It is sectional drawing of a grease enclosure deep groove ball bearing.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Roller bearing cage 2 Cage body 3 Cage claw 4 Rolling element holding pocket 5 Flat part 6 Grease-filled deep groove ball bearing 7 Inner ring 8 Outer ring 9 Rolling element 10 Seal member 11 Lubricating grease

Claims (5)

A rolling bearing cage comprising a molded product of a synthetic resin composition that holds rolling elements of a rolling bearing,
The shaped body is a porous resin body having a communication hole ratio of 30% or more, Ri vapor pressure at 40 ° C. the name impregnated with 1.0 × 10 ^-5 Pa or less of the lubricating oil,
The resin porous body is formed by molding a resin containing at least one pore forming material selected from an organic alkali metal salt and an organic alkaline earth metal salt, and then dissolving the pore forming material. A rolling bearing retainer comprising a communication hole obtained by extracting the pore forming material from the molded body using a solvent that does not dissolve the resin .   The rolling bearing retainer according to claim 1, wherein the lubricating oil is an alkylated cyclopentane oil.   The rolling bearing retainer according to claim 1, wherein the lubricating oil is perfluoropolyether oil. An inner ring having a rolling surface on the outer peripheral surface and an outer ring having a rolling surface on the inner peripheral surface are arranged concentrically, and hold a plurality of rolling elements interposed between the both rolling surfaces, and the plurality of rolling elements A rolling bearing with a cage
The rolling bearing according to any one of claims 1 to 3 , wherein the cage is a rolling bearing cage. A grease-enclosed rolling bearing in which lubricating grease is enclosed around the plurality of rolling elements,
The rolling bearing according to claim 4, wherein the base oil of the lubricating grease has a vapor pressure at 40 ° C. of 1.0 × 10 ⁻⁵ Pa or less.

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