JP4541765B2 - 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.

  Conventional cages for rolling bearings are made of metal, polyamide resin, polyacetal resin, polybutylene terephthalate resin, etc. Especially when synthetic resin is used, it can be injection molded synthetic resin alone or molded synthetic resin Synthetic resin compositions reinforced by adding glass fiber, carbon fiber, organic fiber or the like to the material have been used. Lubricating oil or semi-solid lubricants such as lubricating grease have been used for lubricating rolling bearings equipped with such cages.

  However, when a large amount of semi-solid lubricant such as lubricating grease is used, the torque for rotating the rotating shaft supported by the bearing increases due to the stirring resistance caused by this lubricant, and the torque fluctuation during rotation Also grows. In particular, grease lubricated rolling bearings equipped with conventional cages rotate the shaft supported by the bearing due to the agitation resistance of a large amount of lubricating grease when the rotational speed of the shaft (inner ring or outer ring of the rolling bearing) increases. The required torque increases, and the bearing temperature rises. For this reason, torque fluctuations are likely to occur, and lubricating grease leakage is likely to occur. Further, there is a problem that a relatively large amount of dust tends to float around the bearing due to the presence of the lubricating grease.

In order to improve these problems, a rolling bearing cage or the like in which a cage material is impregnated with a lubricant and has a lubrication function has been proposed.
For example, in a cage for bearings (Patent Document 1) in which fluorinated oil is impregnated with a polyamide-imide resin molded into a porous shape by compression molding, a cage molded with an oil-containing plastic composed of a binder containing oil and a base material Further, a material impregnated with a lubricating oil (Patent Document 2), a polyolefin resin and a lubricating oil mixed together, a resin composition molded into a cage shape (Patent Document 3), a synthetic resin and a fibrous oil conducting material And a lubricating oil are mixed, and the resin composition is molded into a cage shape (Patent Document 4). Porous silica is impregnated with a lubricating oil and blended into a synthetic resin, and the resin composition is shaped into a cage shape. (Patent Document 5) and the like are known.

However, bearing cages made by impregnating a fluorinated oil with a polyamideimide resin that has been formed into a porous shape by compression molding are sintered after compression molding a powdery resin. In fact, the porosity cannot exceed 30%. For this reason, the amount of lubricating oil that can be impregnated is below this porosity, and the amount of lubricating oil may be insufficient depending on the use conditions. Moreover, the resin material which can compression-mold a communicating hole is limited, and there exists a problem that the resin which can be used is restrict | limited.
In addition, a cage molded with an oil-containing plastic composed of an oil-containing binder and a base material and impregnated with a lubricating oil has a high temperature (120 ° C to 130 ° C) for a long time (about 7 days) in order to increase the oil content. ) Since it is necessary to immerse in lubricating oil, there is a risk of deterioration of the lubricating oil and the resin forming the cage and a large dimensional change, resulting in poor product stability and maintaining stable lubrication over a long period of time. There is a problem that is difficult.
When a polyolefin resin and lubricating oil are mixed and the resin composition is molded into a cage shape, the lubricating oil is retained in the polyolefin resin by using a highly oil-absorbing polyolefin resin. There is little oil. Even if the lubricating oil is uniformly dispersed in the resin, the lubricating oil in the vicinity of the surface begins to bleed, but it is technically difficult to ooze out from the inside at a stable rate over a long period of time.
Further, when lubricating oil is blended, a problem arises in terms of manufacturing when the blending amount increases. For example, the screw slips during injection molding, the measurement becomes unstable and the cycle time becomes long, the dimensional accuracy is difficult, the lubricant adheres to the mold surface, and the finish of the molding surface deteriorates. It becomes easy. For this reason, there is a problem that the type of resin that can be used, the type of lubricating oil, viscosity, vapor pressure, and decomposition temperature are limited.

Mixing fibrous oil conducting material and lubricating oil in synthetic resin, molding the resin composition into a cage shape, or impregnating porous silica with lubricating oil and blending into synthetic resin, For those molded into a cage shape, resin and lubricating oil are mixed before molding. In this case, the lubricating oil must withstand the molding temperature of the resin, and the type of resin that can be used in the same manner as described above, and the type of lubricating oil, viscosity, vapor pressure, and decomposition temperature are limited. Since the screw slides at the time of injection molding, it is necessary to suppress the amount of lubricating oil that can be blended in order to stably feed the raw material into the molding machine. Since the amount of lubricating oil is less than 30% at the maximum, the amount of lubrication may be insufficient depending on the usage conditions of the rolling bearing.
Japanese Patent Laid-Open No. 61-6429 JP-A-1-93623 JP-A-8-21450 Japanese Patent Laid-Open No. 11-166541 JP 2000-98152 A

  The present invention has been made to cope with such a problem. In a resin cage containing a lubricating oil, the amount of oil contained in the cage is increased and the use efficiency of the lubricating oil is increased. Use a cage that can be used without enclosing grease or reducing the amount of lubrication grease, and a cage that allows any combination of resin material and lubricating oil depending on the intended use, and this cage. The purpose is to provide rolling bearings.

The rolling bearing cage of the present invention is a rolling bearing cage made of a synthetic resin composition molded body that holds the rolling element of the rolling bearing, and the molded body has a communication porosity of 30% or more. The resin porous body is impregnated with a lubricant.
The porous resin body is molded using a solvent that dissolves the pore-forming material and does not dissolve the resin, after molding a resin containing a pore-forming material, which is a weak alkaline substance, into a molded body. It has the communicating hole obtained by extracting a pore formation material from a body.
The pore-forming material is at least one selected from organic alkali metal salts and organic alkaline earth metal salts.

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 cage for holding the plurality of rolling elements, and 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 lubricating oil impregnated in the porous resin body and the base oil of the lubricating grease are rolling bearing operating environment conditions. It is characterized by mutual dissolution.
In addition, the amount of the lubricating grease filled is 5 to 20% of the total space volume of the bearing.

  Since the rolling bearing retainer of the present invention is formed by impregnating a porous resin body having a communication porosity of 30% or more with a lubricant, the rolling bearing using this retainer has a small torque required for rotation and a torque. Fluctuation of less. Further, since the lubricating oil is supplied from the cage over a long period of time, excellent durability is exhibited. Further, since the lubricating oil impregnated in the porous resin body and the base oil of the lubricating grease are mutually dissolved under the rolling bearing operating environment conditions, the amount of grease filled can be 5 to 20% of the total space volume of the bearing. Therefore, a rolling bearing with less grease leakage can be obtained.

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 rate) 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 the conventional sintered resin molding 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 resin porous 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 diameter 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.

  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.
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, 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 diameter 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 the resin powder, the porous body forming material, and the filler. If the volume is 30% by volume or less, the pores of the porous body are difficult to become continuous pores, and if it is 90% by volume or more, the 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, it is obtained by impregnating a lubricant into a resin porous body having a communicating porosity of 30% or more obtained by extracting a pore-forming material using a solvent that does not dissolve the molded body.
As the lubricant, lubricating oil is preferable, for example, mineral oil such as spindle oil, refrigerating machine oil, turbine oil, machine oil, dynamo oil, paraffinic mineral oil, naphthenic mineral oil, polybutene, polyalphaolefin, alkylbenzene, alkylnaphthalene, fat. Non-carbonized hydrocarbon synthetic oils such as cyclic compounds, or natural oils and fats, polyol ester oils, phosphate esters, diester oils, polyglycol oils, silicone oils, polyphenyl ether oils, alkyl diphenyl ether oils, fluorinated oils, etc. Any commonly used lubricating oil such as a hydrogen-based synthetic oil can be used without any particular limitation.
In the above lubricating oil, as long as the purpose of the present invention is not impaired, an extreme pressure agent, an antioxidant, a rust inhibitor, a pour point depressant, an ashless dispersant, a metal detergent, an interface Activators, wear modifiers, etc. can be blended. As the antioxidant, phenol, amine, sulfur and the like can be used alone or in combination.

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.

Since this bearing 6 uses the rolling bearing cage of the present invention as the cage 1, it 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.
Further, even when lubricating grease is enclosed, the operation can be performed in a smaller amount than the amount of lubricating grease enclosed normally.
When encapsulating the lubricating grease, the lubricating oil that is impregnated in the porous resin body of the cage and the oil that mutually dissolves under the rolling bearing operating environment conditions are used as the base oil of the lubricating grease. 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.

Examples of the base oil constituting the lubricating grease include mineral oils such as paraffinic mineral oil and naphthenic mineral oil, hydrocarbon synthetic oils such as polybutene, polyalphaolefin, alkylbenzene, alkylnaphthalene, and alicyclic compounds, or natural oils and fats. And non-hydrocarbon synthetic oils such as polyol ester oil, phosphate ester, diester oil, polyglycol oil, silicone oil, polyphenyl ether oil, alkyl diphenyl ether oil, and fluorinated oil. Any oil can be used without any particular limitation.
Examples of the thickener include metal soap-based thickeners such as aluminum soap, lithium soap, sodium soap, composite lithium soap, composite calcium soap, composite aluminum soap, and urea compounds such as diurea compounds and polyurea 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.

The rolling bearing having the above-described configuration incorporating the cage of the present invention has a small torque required for rotation and a small torque fluctuation. For this reason, since excellent lubrication is performed over a long period of time, excellent durability is exhibited. Even when lubricating grease is sealed, the amount of lubricating grease charged can be made smaller than usual, so that a rolling bearing with less lubricating grease leakage can be obtained.
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
Ultra high molecular weight polyethylene powder (Miperon XM220 manufactured by Mitsui Chemicals, Inc.) and sodium benzoate powder (reagent manufactured by Wako Pure Chemical Industries, Ltd.) are mixed in a mixer at a volume ratio of 50:50 for 5 minutes to obtain a mixed powder Got. Using this mixed powder, a disk having a diameter of 30 mm and a thickness of t5 mm was molded by a heat compression molding method (200 ° C. × 30 minutes). The molded body 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 48%. This porous material was vacuum impregnated with polyalphaolefin oil (PAO) (Shinfluid 801 manufactured by Nippon Steel Chemical Co., Ltd. (viscosity: 46 mm ² / s (40 ° C.)) at 60 ° C. The oil content was 45% of the total volume. This sample was used to conduct the impregnation oil oozing test, which is an important characteristic of a cage.

Example 2
Mixed powder of ethylene tetrafluoride resin powder (M15 manufactured by Daikin Industries, Ltd.) and sodium benzoate powder (reagent manufactured by Wako Pure Chemical Industries, Ltd.) at a volume ratio of 50:50 with a mixer for 5 minutes. Got. Using this mixed powder, a disk having a diameter of 30 mm and a thickness of t5 mm was molded by a heat compression molding method (350 ° C. × 30 minutes). The molded body 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 48%. This porous body was vacuum impregnated with synthetic hydrocarbon oil (Lucant HC-20 manufactured by Mitsui Chemicals Co., Ltd. (viscosity 155 mm ² / s (40 ° C.)) at 100 ° C. The oil content was 44% of the total volume. This sample was used to conduct the impregnation oil bleeding test.

Example 3
Polyetheretherketone (PEEK) resin powder (150 PF manufactured by Victrex Co., Ltd.), carbon fiber, and sodium benzoate powder (reagent manufactured by Wako Pure Chemical Industries, Ltd.) in a volume ratio of 50:10:40 The mixture was melt kneaded and then pulverized to obtain a mixed powder. Using this mixed powder, a disk having a diameter of 30 mm and a thickness of t5 mm was molded by a heat compression molding method (350 ° C. × 30 minutes). The molded body 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 39%. The porous body was vacuum impregnated with polyalphaolefin oil (PAO) (Shinflud 801 manufactured by Nippon Steel Chemical Co., Ltd. (viscosity: 46 mm ² / s (40 ° C.)) at 60 ° C. The oil content was 38 with respect to the total volume. This sample was used to conduct a test for bleeding of impregnated oil.

Comparative Example 1
Ultra high molecular weight polyethylene powder (Miperon XM220 manufactured by Mitsui Chemicals, Inc.), polyethylene wax (Suntite S manufactured by Seiko Chemical Co., Ltd.) and poly alpha olefin oil (PAO) (Shinflud 801 manufactured by Nippon Steel Chemical Co., Ltd. (viscosity 46 mm ²⁾ / S (40 ° C.)) at a volume ratio of 20:15:65 and put into a mold, and a disk having a diameter of 30 mm and a thickness of t5 mm was formed by a free sintering method (160 ° C. × 30 minutes). The oil content after molding was 60% with respect to the total volume.

Impregnation oil bleeding test:
The disks produced in Example 1, Example 2, Example 3 and Comparative Example 1 were measured with quantitative filter paper No. The amount of impregnated oil transferred to a fixed amount filter paper was examined as the amount of oil reduction in the disc, sandwiched between 5C (φ100 mm, 2 sheets). The results are shown in FIG.
As shown in FIG. 3, in each of the examples, bleeding of about 75% of the initial oil content was possible. However, in Comparative Example 1, although the initial oil content was about twice that of Example 2, the amount of the impregnated oil oozed out was about 20% of Example 2. It can be seen that the oil-containing porous body of each example has communication holes, and the impregnated oil can be used effectively.

Example 4
Polyetheretherketone (PEEK) resin powder (150 PF manufactured by Victrex Co., Ltd.), carbon fiber, and sodium benzoate powder (reagent manufactured by Wako Pure Chemical Industries, Ltd.) in a volume ratio of 50:10:40 The mixture was melt kneaded and then pulverized to obtain a mixed powder. Using this mixed powder, a crown type cage for ball bearing # 608 was molded by injection molding. The molded body 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 39%. The porous body was vacuum impregnated with synthetic hydrocarbon oil (Lucant HC-20 (viscosity 155 mm ² / s (40 ° C.)) manufactured by Mitsui Chemicals, Inc.) at 100 ° C. The oil content was 39% of the total volume. This cage was incorporated into a # 608 bearing, and a torque fluctuation test was performed using this rolling bearing.

Comparative Example 2
A crown type cage for ball bearing # 608 was molded by injection molding using polyamide 66 resin filled with 25% by weight of glass fiber. Incorporating the retainer # 608 bearing further synthetic hydrocarbon oil (Mitsui Chemicals Co., Ltd. Lucant HC-20 (viscosity ^{155mm 2 / s (40 ℃)} ) as the base oil, the thickener lithium soap 0.12 g of lubricating grease (30% of the total space volume of the bearing) was enclosed, and a torque fluctuation test was performed using this rolling bearing.

Torque fluctuation test:
The # 608 bearings obtained in Example 4 and Comparative Example 2 were set in an endurance test apparatus, respectively, operated at an axial load of 970 N and a rotational speed of 500 rpm, and the torque fluctuation of the rotating shaft was measured. The results are shown in FIG.
As shown in FIG. 4, Example 4 has a low torque over 800 hours and has a small torque fluctuation range. In Comparative Example 2, the torque tended to increase with time, and the fluctuation range of the torque was also large.
The bearing of Example 4 can be operated stably, and can be operated for a long time only with the lubricating oil impregnated in the cage.

Example 5
The # 608 bearing obtained in Example 4 was filled with 0.04 g (10% of the total space volume of the bearing) of the lubricating grease used in Comparative Example 2. As a result of performing a torque fluctuation test using this rolling bearing, the torque was low for 800 hours as in Example 4, and the fluctuation width of the torque was small.

  Since the rolling bearing retainer of the present invention can supply lubricating oil over a long period of time, the rolling bearing using this retainer exhibits excellent durability with low torque and small fluctuation width. There are few leaks. For this reason, it can be used as a versatile basic part.

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. It is a figure which shows the oozing-out test of impregnation oil. It is a figure which shows a torque fluctuation test result.

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 compacts, Ri Na was impregnated with lubricant to a resin porous body having continuous pores of not less than 30%,
The resin porous body is formed using a solvent that dissolves the pore forming material and does not dissolve the resin after molding a resin containing a pore forming material that is a weak alkaline substance into a molded body. A rolling bearing retainer having a communicating hole obtained by extracting the pore forming material from the bearing.   The rolling bearing retainer according to claim 1, wherein the pore forming material is at least one selected from an organic alkali metal salt and an organic alkaline earth metal salt. 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 claim 1 or 2, wherein the cage is the cage for rolling bearings. A grease-enclosed rolling bearing in which lubricating grease is enclosed around the plurality of rolling elements,
The rolling bearing according to claim 3, wherein the lubricating oil impregnated in the porous resin body and the base oil of the lubricating grease are mutually dissolved under rolling bearing operating environment conditions.   The rolling bearing according to claim 3 or 4, wherein the amount of the lubricating grease enclosed is 5 to 20% of the total space volume of the bearing.

Images