JP2008286375A - Composition for sliding member and rolling bearing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent the occurrence of separation of a coating film formed on a surface of a cage and elution of a coating film component, even in use in an environment contacting with lubricating oil including a sulfur-based additive or in an atmosphere including a sulfur-based compound. <P>SOLUTION: This composition for a sliding member is used for a mechanical part of forming at least a surface part of the sliding member, wherein the composition includes fullerene and at least one disulfide selected from molybdenum disulfide and tungsten disulfide in a polyimide resin, and the fullerene is included by 0.1-10 volume%, and the disulfide is included by 0.5-20 volume% to the whole composition for the sliding member, and the mechanical part has a plurality of rolling elements 3 and the cage 2 holding these rolling elements 3. The rolling bearing 1 is used in the environment contacting with the lubricating oil including the sulfur-based additive. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  INDUSTRIAL APPLICABILITY The present invention is used in a sliding member composition using a synthetic resin as a binder and an environment in contact with a lubricating oil containing a sulfur-based additive using the sliding member composition or an atmosphere containing a sulfur-based compound. It relates to rolling bearings.

The two-cycle engine includes a piston that performs linear reciprocating motion by combustion of an air-fuel mixture, a crankshaft that outputs rotational motion, and a connecting rod that couples the piston and crankshaft to convert linear reciprocating motion into rotational motion.
The connecting rod is formed by providing a large end portion below the linear rod body and a small end portion above. The crankshaft is rotatably supported at the large end of the connecting rod, and the piston pin connecting the piston and the connecting rod is rotatably supported at the small end of the connecting rod through roller bearings attached to the engagement holes. The roller bearing that supports the rotating shaft includes a plurality of rollers and a cage that holds the plurality of rollers.

  The roller bearings that are attached to the engagement holes provided at the small and large ends of the connecting rod and support the piston pin and the crankshaft are subjected to a heavy load even though the projected area of the bearing is small. Needle roller bearings that can be used and have high rigidity are used. Here, the needle roller bearing includes a plurality of needle rollers and a cage that holds the plurality of needle rollers. The cage is provided with pockets for holding the needle rollers, and the interval between the needle rollers is held by a pillar portion located between the pockets. Needle roller bearings at the small and large ends of the connecting rod are positively attached to the small and large ends in order to reduce the load on the needle roller bearing due to the rotation and revolution of the needle rollers. It is used in the outer diameter guide in which the outer diameter surface of the cage is brought into contact with the inner diameter surface of the provided engagement hole.

  On the other hand, a general rolling bearing has an inner ring, an outer ring, a sealing material, and the like sealed inside, and a rolling element and a cage are provided inside the bearing, and grease is filled, and the rolling element and the cage are filled with the grease. Is always lubricated. On the other hand, the needle roller bearing does not have an inner ring, an outer ring, a sealing material, and the like, so the inside of the bearing is not sealed and grease cannot be filled inside the bearing. Therefore, when the needle roller bearing rotates, it is necessary to always supply lubricating oil to the sliding portion with a pump or the like.

Since the pump or the like starts operating simultaneously with the rotation of the needle roller bearing, the lubricating oil has not yet spread over the entire needle roller bearing immediately after the rotation starts, and sufficient lubrication is not performed. For this reason, a large friction is generated between the cage and the needle roller, and the surface of the cage or needle roller is worn, or the cage outer diameter surface and the actual housing inner surface are worn. There is a risk of burning.
Therefore, in order to prevent wear and seizure immediately after the start of rotation of the needle roller bearing, there has been proposed a technique of previously forming a film having lubricity on the surface of the cage.

  For example, a hard diamond-like carbon (hereinafter referred to as DLC) film is formed on the guide surface of a rolling element of a cage made of steel having a hardened layer formed on the surface by carburizing treatment by sputtering or the like. A method of forming a soft metal film such as is known (see Patent Document 1). This soft metal coating reduces the friction between the cage and the needle roller, and the friction between the cage outer diameter surface and the housing inner diameter surface. It is said that seizure can be prevented, and even if this soft metal film is worn with use, the underlying DLC film is newly exposed and the DLC film prevents wear.

  A technique for directly forming the soft metal film on the surface of the cage by a plating method has also been proposed. For example, a method of forming a silver plating film of about 25 to 50 μm on the surface of low carbon steel is known (see Patent Document 2). This silver plating film reduces friction between the cage and needle rollers, and between the cage outer diameter surface and the housing, respectively. It can be prevented. Furthermore, since the copper plating film has the effect of reducing the friction between the cage and the needle rollers like the silver plating film, it is said that seizure can be prevented.

  However, in the method shown in Patent Document 1, the hard coating is exposed after the soft metal is worn away and the housing inner diameter portion slides on the hard coating. In this case, the cage is not worn, but there is a possibility that the inner diameter portion of the housing is worn by the hard coating on the surface of the cage. Moreover, since the carburizing process is performed on the cage from the viewpoint of manufacturing, the DLC film is formed by the sputtering apparatus, and the soft metal film is formed, the work process is complicated and requires a lot of man-hours. Moreover, since the sputtering apparatus is expensive and the production efficiency is not good, there is a problem that the processing using the apparatus is expensive.

  In the method shown in Patent Document 2, in a lubricating system containing a sulfur-based additive, a silver plating film formed on the surface of the cage is combined with a sulfur component contained in the lubricating oil to form silver sulfide. Silver covers the surface of the silver plating film. Since this silver sulfide is fragile compared to silver, the coating is peeled off or inferior in oil resistance, so the coating is dissolved by the lubricating oil. As a result, there is a problem that the friction between the outer diameter surface of the cage where the silver plating film has disappeared and the inner diameter surface of the housing increases, and seizure tends to occur. Similarly, the copper plating film also has a problem that copper sulfide is generated and the lubricity of the cage deteriorates due to peeling or dissolution of the film.

In addition, the present inventors have proposed a technique for forming a resin film in which fullerene is blended on the surface of a cage (Patent Document 3). By blending fullerene, a lubricating film having excellent wear resistance can be formed.
However, it is not known about the behavior of a wear-resistant lubricating film containing fullerene in a lubricating system or atmosphere containing a sulfur-based additive.
Japanese Patent Laying-Open No. 2005-147306 JP 2002-195266 A JP 2005-299852 A

  The present invention has been made to cope with such problems, and is formed on the surface of a cage even when used in an environment in contact with a lubricating oil containing a sulfur-based additive or in an atmosphere containing a sulfur-based compound. An object of the present invention is to provide a composition for a sliding member in which peeling of the coated film and elution of the coating component are unlikely to occur, and a rolling bearing using the composition for sliding member.

The composition for a sliding member of the present invention is a composition for a sliding member that is used for a machine part having at least a surface portion formed of a sliding member. The composition includes a fullerene, a disulfide, a synthetic resin, and the like. At least one disulfide selected from molybdenum and tungsten disulfide, and the fullerene content is 0.1 to 10% by volume and the disulfide content is 0.5 to 20 with respect to the entire sliding member composition. It is characterized by being included in volume%.
Further, the sliding member formed on the surface part of the machine part is a synthetic resin film, and particularly a polyimide resin film.

The rolling bearing of the present invention includes a plurality of rolling elements and a cage that holds the rolling elements, and is used in an environment in contact with a lubricating oil containing a sulfur-based additive or an atmosphere containing a sulfur-based compound. A rolling bearing is characterized in that the composition film for a sliding member of the present invention is formed on a surface portion of the cage.
Further, the cage is a molded body of an iron-based metal material. The rolling element has a roller shape, particularly a needle roller shape.
The rolling bearing may be attached to an engagement hole provided at a large end portion of a connecting rod that supports a crankshaft that outputs rotational motion and converts linear reciprocating motion into rotational motion.

  In the composition for a sliding member of the present invention, the fullerene and the disulfide are blended in a predetermined amount in the synthetic resin, so that the fine particle-shaped fullerene and the disulfide powder are blended uniformly in the resin body or coating. As a result, due to these synergistic effects, the wear resistance and peel resistance are improved, and at the same time, the friction coefficient is lowered.

  The rolling bearing of the present invention includes a plurality of rolling elements and a cage that holds the rolling elements, and is used in an environment that contacts a lubricating oil containing a sulfur-based additive or an atmosphere that includes a sulfur-based compound. Since it is a bearing and the composition film for a sliding member of the present invention is formed on the surface portion of the cage, peeling of the film and elution of the film component into the lubricating oil can be suppressed. Thus, the lubricity of the cage can be maintained for a longer period.

  Since the rolling element has a roller shape, it can receive a heavy load. Further, by using a highly rigid needle roller bearing, it is possible to receive a higher load.

  The rolling bearing of the present invention is attached to an engagement hole provided at a large end portion of a connecting rod that supports a crankshaft that outputs rotational motion and converts linear reciprocating motion into rotational motion, and has an outer diameter surface of the cage. Since the above-mentioned polyamide-imide resin film can maintain the lubricity of the cage for a longer period than conventional metal plating, wear of the cage outer diameter surface and the engagement hole inner diameter surface is prevented, The lifetime of the entire apparatus can be extended.

  The synthetic resin that can be used in the composition for a sliding member of the present invention is not particularly limited as long as it is a material that has oil resistance, has high coating strength when formed into a coating, and excellent wear resistance. Examples of such resins include epoxy resins, phenol resins, polycarbodiimide resins, furan resins, bismaleimide triazine resins, unsaturated polyester resins, silicone resins, polyamino bismaleimide resins, aromatic polyimide resins and other thermosetting resins, polyolefins Resin, polyacetal resin, polyamide resin, polyphenylene ether resin, polyphenylene sulfide resin, polysulfone resin, polyether sulfone resin, polyetherimide resin, thermoplastic polyimide resin, aromatic polyamideimide resin, polybenzimidazole resin, polyether ketone resin And thermoplastic resins such as polyether nitrile resin, fluororesin, and aromatic polyester resin. Among these, preferred are aromatic polyamideimide resin, aromatic polyimide resin, epochine resin, phenol resin, polyphenylene sulfide resin and the like. These synthetic resins can be blended with various fillers in the form of fibers and particles as necessary.

  In the present invention, a particularly preferable synthetic resin is a polyimide resin excellent in film forming ability. Examples of the polyimide resin include a polyimide resin having an imide bond in the molecule and a polyamideimide resin having an imide bond and an amide bond in the molecule.

Among the polyimide resins, an aromatic polyimide resin is preferable. The aromatic polyimide resin is a resin having a repeating unit represented by Chemical Formula 1, and a polyamic acid that is a precursor of a resin having a repeating unit represented by Chemical Formula 1 can also be used. R ₁ is the residue of an aromatic tetracarboxylic acid or derivative thereof, and R ₂ is the residue of an aromatic diamine or derivative thereof. Examples of such R ₁ or R ₂ include a phenyl group, a naphthyl group, a diphenyl group, and an aromatic group in which these are connected by a connecting group such as a methylene group, an ether group, a carbonyl group, or a sulfone group.

  Examples of aromatic tetracarboxylic acids or derivatives thereof include pyromellitic dianhydride, 2,2 ′, 3,3′-biphenyltetracarboxylic dianhydride, 3,3 ′, 4,4′-biphenyltetra Carboxylic dianhydride, 3,3 ′, 4,4′-benzophenone tetracarboxylic dianhydride, 1,2,5,6-naphthalene tetracarboxylic dianhydride, bis (2,3-dicarboxyphenyl) Examples thereof include methanoic dianhydride, and these are used alone or in combination.

  Examples of aromatic diamines or derivatives thereof include 4,4′-diaminodiphenyl ether, 3,3′-diaminodiphenyl sulfone, 4,4′-diaminodiphenylmethane, metaphenylenediamine, paraphenylenediamine, and 4,4′-bis. Examples include diamines such as (3-aminophenoxy) biphenyl ether or diisocyanates.

Examples of the aromatic polyimide resin obtained by a combination of the aromatic tetracarboxylic acid or derivative thereof and the aromatic diamine or derivative thereof include those having a repeating unit shown in Table 1. These are resins having no heteroatoms in R ₁ and R ₂ .

In the aromatic polyimide resin in Table 1, polyimides C and D having a high ratio of aromatic rings in the molecule are preferable, and polyimide D is particularly suitable for the present invention. As a commercial item of aromatic polyimide resin varnish, U varnish by Ube Industries, Ltd. is mentioned, for example.

The polyamide-imide resin that can be used in the present invention is a resin having an amide bond and an imide bond in the polymer main chain, and can be obtained by reacting a polycarboxylic acid or a derivative thereof with a diamine or a derivative thereof.
Examples of polycarboxylic acids include dicarboxylic acids, tricarboxylic acids, and tetracarboxylic acids. Polyamideimide resins include (1) combinations of dicarboxylic acids and tricarboxylic acids and diamines, and (2) dicarboxylic acids and tetracarboxylic acids and diamines. (3) a combination of tricarboxylic acid and diamine, and (4) a combination of tricarboxylic acid or tetracarboxylic acid and diamine. Each of the polycarboxylic acid and the diamine may be a derivative. Examples of polycarboxylic acid derivatives include acid anhydrides and acid chlorides, and examples of diamine derivatives include diisocyanates. Diisocyanate may be used that has been stabilized with a blocking agent necessary to prevent the isocyanate group from changing over time. Examples of the blocking agent include alcohol, phenol and oxime.
Moreover, an aromatic and an aliphatic compound can be used for polycarboxylic acid and diamine, respectively. The polyamideimide resin that can be used in the present invention is preferably excellent in elongation, and it is preferable to use an aliphatic compound in combination with an aromatic compound.
Further, it can be modified with an epoxy compound.

Examples of tricarboxylic acid or derivatives thereof include trimellitic anhydride, 2,2 ′, 3-biphenyltricarboxylic anhydride, 3,3 ′, 4-biphenyltricarboxylic anhydride, 3,3 ′, 4-benzophenone Examples include tricarboxylic acid anhydride, 1,2,5-naphthalene tricarboxylic acid anhydride, 2,3-dicarboxyphenylmethylbenzoic acid anhydride, and these are used alone or in combination.
Trimellitic anhydride is preferred because it is mass-produced and is easy to use industrially.

  Examples of tetracarboxylic acid or derivatives thereof include pyromellitic dianhydride, 3,3 ′, 4,4′-benzophenone tetracarboxylic dianhydride, 3,3 ′, 4,4′-biphenyltetracarboxylic acid Dianhydride, 1,2,5,6-naphthalenetetracarboxylic dianhydride, 2,3,5,6-pyridinetetracarboxylic dianhydride, 1,4,5,8-naphthalenetetracarboxylic dianhydride 3,4,9,10-perylenetetracarboxylic dianhydride, 4,4'-sulfonyldiphthalic dianhydride, m-terphenyl-3,3 ', 4,4'-tetracarboxylic acid Dianhydride, 4,4'-oxydiphthalic dianhydride, 1,1,1,3,3,3-hexafluoro-2,2-bis (2,3- or 3,4-dicarboxyphenyl) propane Dianhydride, 2,2-bis (2,3- or , 4-Dicarboxyphenyl) propane dianhydride, 2,2-bis [4- (2,3- or 3,4-dicarboxyphenoxy) phenyl] propane dianhydride, 1,1,1,3,3 , 3-Hexafluoro-2,2-bis [4- (2,3- or 3,4-dicarboxyphenoxy) phenyl] propane dianhydride, 1,3-bis (3,4-dicarboxyphenyl)- 1,1,3,3-tetramethyldisiloxane dianhydride, butanetetracarboxylic dianhydride, bicyclo- [2,2,2] -oct-7-ene-2: 3: 5: 6-tetracarboxylic An acid dianhydride etc. are mentioned.

  Examples of dicarboxylic acids or derivatives thereof include succinic acid, glutaric acid, adipic acid, azelaic acid, suberic acid, sebacic acid, decanedioic acid, dodecanedioic acid, dimer acid, isophthalic acid, terephthalic acid, phthalic acid, naphthalenedicarboxylic acid , Oxydibenzoic acid, aliphatic dicarboxylic acid having carboxyl groups at both ends of a polybutadiene oligomer (Nisso-PB, C series manufactured by Nippon Soda Co., Ltd., Hycar-RLP, CT series manufactured by Ube Industries, Ltd., manufactured by Thiokol Co., Ltd. HC-polymer series, General Tire's Telagen series, Phillips Petroleum's Butaretz series, etc.), carbonate diols (trade names PLACEL, CD-205, 205PL, manufactured by Daicel Chemical Industries, Ltd.) 5HL, 210,210PL, 210HL, 220,220PL, hydroxyl equivalent or more carboxyl equivalent become dicarboxylic acid ester dicarboxylic acid obtained by reaction of 220HL) can be mentioned.

Examples of diamines or derivatives thereof include 4,4'-diphenylmethane diisocyanate, tolylene diisocyanate, xylylene diisocyanate, 4,4'-diphenyl ether diisocyanate, 4,4 '-[2,2-bis (4- Phenoxyphenyl) propane] diisocyanate, biphenyl-4,4'-diisocyanate, biphenyl-3,3'-diisocyanate, biphenyl-3,4'-diisocyanate, 3,3'-dimethylbiphenyl-4,4'-diisocyanate, 2, 2,2′-dimethylbiphenyl-4,4′-diisocyanate, 3,3′-diethylbiphenyl-4,4′-diisocyanate, 2,2′-diethylbiphenyl-4,4′-diisocyanate, 3,3′-dimethoxy Biphenyl-4,4'-diisocyanate 2,2′-dimethoxybiphenyl-4,4′-diisocyanate, naphthalene-1,5-diisocyanate, naphthalene-2,6-diisocyanate, hexamethylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, isophorone diisocyanate 4,4'-dicyclohexylmethane diisocyanate, transcyclohexane-1,4-diisocyanate, hydrogenated m-xylylene diisocyanate, lysine diisocyanate, carbonate diols (trade names PLACEL, CD-205, 205PL manufactured by Daicel Chemical Industries, Ltd.) , 205HL, 210, 210PL, 210HL, 220, 220PL, 220HL), obtained by reacting diisocyanate having an isocyanate equivalent of a hydroxyl equivalent or higher Diisocyanate such as diisocyanate.

  Examples of diamines include siloxane diamines (silicone oil X-22-161AS (amine equivalent 450), X-22-161A (amine equivalent 840), X-22-161B (amine) having amino groups bonded to both ends of dimethylsiloxane. Equivalent 1500), X-22-9409 (amine equivalent 700), X-22-1660B-3 (amine equivalent 2200) (above, manufactured by Shin-Etsu Chemical Co., Ltd., trade name), BY16-853 (amine equivalent 650), BY16 -853B (amine equivalent 2200) (above, manufactured by Toray Dow Corning Silicone Co., Ltd., trade name)), both-terminal aminated oligomers such as both-terminal aminated polyethylene and both-terminal aminated polypropylene, both-terminal aminated polymer, oxyalkylene Diamines with groups (Jeffamine D series, Jeffamine ED series, Jeffamine XTJ-511, Jeffamine XTJ-512, both of San Techno Chemical Co., trade name), and the like.

  Unlike an aromatic polyimide resin, a polyamide-imide resin having a repeating unit of an amide bond and an imide bond in a resin solution state without passing through a precursor is particularly preferred in the present invention. Further, diisocyanate-modified, BPDA-modified, sulfone-modified and rubber-modified resins of polyamideimide resin can be used. Examples of commercially available polyamideimide resin varnishes include HPC5020 and HPC7200 manufactured by Hitachi Chemical Co., Ltd.

  In the present invention, the polyamideimide resin is preferably a polyamideimide resin having an elongation percentage of the resin film of 60% to 120%. If the elongation is less than 60%, the adhesiveness to the base material is poor and peeling easily occurs, and peeling or elution of the metal base material easily occurs in an environment in contact with a lubricating oil containing a sulfur-based additive. If the elongation exceeds 120%, the heat resistance is lowered and the oil tends to swell. As a commercial item of the polyamide-imide resin whose elongation rate of a resin film is 60%-120%, Hitachi Chemical Co., Ltd. make and brand name HPC7200-30 are mentioned, for example.

In the present invention, the elongation percentage of the polyamideimide resin film is measured by the following method.
The polyamide-imide resin solution is applied onto a glass substrate that has been degreased with acetone and then cleaned with nitrogen gas blow, pre-dried at 80 ° C for 30 minutes and then at 150 ° C for 10 minutes, and finally the molecular structure of the polyamide-imide resin is obtained. Dry for 30 minutes at a suitable curing temperature. The cured coating film is peeled off from the glass substrate to obtain a resin film with a thickness of 80 ± 8 μm. This film is made into a 10 mm × 60 mm strip test piece, the distance between chucks is 20 mm, the tensile speed is 5 mm / Elongation (%) is measured with a tensile tester at room temperature in minutes.

Fullerene blended in the polyimide resin is a carbon molecule composed of a carbon 5-membered ring and a 6-membered ring and having various polyhedral structures closed in a spherical shape. As a third carbon allotrope following graphite and diamond, H. W. Kroto and R.K. E. It is a new carbon material discovered by Smalley et al. As a typical molecular structure, a C _{60 having} a so-called soccer ball-like structure in which ₆₀ carbon atoms constitute a spherical truncated icosahedron composed of 12 five-membered rings and 20 six-membered rings. Similarly, there are C ₇₀ composed of ₇₀ carbon atoms, and higher fullerenes having a larger number of carbon atoms such as C ₇₆ , C ₇₈ , C ₈₂ , C ₈₄ , C ₉₀ , C ₉₄ , C _96, etc. . Of these, C ₆₀ and C ₇₀ are typical fullerenes. Moreover, a multimer is obtained by making these react. In the present invention, any fullerene can be used, either spherical or multimeric.

  The fullerene production method includes a laser evaporation method, a resistance heating method, an arc discharge method, a thermal decomposition method, etc., and specifically disclosed in, for example, Japanese Patent No. 2802324, which is under reduced pressure or inactive. Fullerenes are obtained by gas existence, generation of carbon vapor, cooling and cluster growth.

On the other hand, in recent years, a combustion method has been put to practical use as an economical and efficient mass production method. As an example of the combustion method, an apparatus in which a burner is installed in a decompression chamber is used, and a hydrocarbon raw material and oxygen are mixed and supplied to the burner while ventilating the inside of the system with a vacuum pump to generate a flame. Then, the soot-like substance produced | generated by the said flame is collect | recovered with the collection | recovery apparatus provided downstream. In this production method, fullerene is obtained as a solvent-soluble component in soot and is isolated by solvent extraction, sublimation or the like. The obtained fullerene is usually a mixture of C ₆₀ , C ₇₀ and higher order fullerene, and can be further purified to isolate C ₆₀ , C _{70 and the} like.
The fullerene used in the present invention is not particularly limited in its structure and production method, but those having a carbon number of C ₆₀ or C ₇₀ or a mixture thereof are particularly preferred.

Fullerene can be used as a solid compounding agent or as a compounding agent obtained by dissolving and dispersing fullerene in an organic solvent. In any case, C ₆₀ , C _{70 and} higher order fullerenes can be used alone or in a mixed state, but these are used in a mixed state from the viewpoint of dispersibility in the resin. It is preferable.
In order to further improve the dispersibility, the average particle size at the time of mixing is 100 μm or less, preferably 50 μm or less, more preferably 10 μm or less.

  The blending ratio of fullerene to the sliding member composition is 0.1 to 10% by volume, preferably 0.1 to 5% by volume of solid fullerene based on the whole composition. If it is less than 0.1% by volume, sufficient wear resistance cannot be obtained, and if it exceeds 10% by volume, the dispersion becomes poor and the wear resistance deteriorates.

  Powdered molybdenum disulfide and tungsten disulfide can be used. From the viewpoint of dispersibility and surface smoothness of the coating, the particle size is 10 μm or less, preferably 5 μm or less. The blending ratio of molybdenum disulfide and tungsten disulfide to the sliding member composition is 0.5 to 20% by volume, preferably 0.5 to 15% by volume, based on the entire composition. If it is less than 0.1% by volume, sufficient friction and wear characteristics cannot be obtained, and if it exceeds 20% by volume, the wear resistance deteriorates.

In the composition for a sliding member of the present invention, a solid lubricant such as polytetrafluoroethylene and graphite is added for the purpose of stabilizing the friction coefficient and improving the initial conformability without reducing the wear resistance. It can be used in combination with fullerene and molybdenum disulfide or tungsten disulfide.
A preferred embodiment of the composition for a sliding member of the present invention is a resin composition in which fullerene and at least one disulfide selected from molybdenum disulfide and tungsten disulfide are dispersed and blended in a polyimide resin. is there.

  The case where the composition for a sliding member of the present invention is applied to a rolling bearing having a metal film that hardly causes elution in an environment in contact with a lubricating oil or sulfur atmosphere containing a sulfur component will be described. As a result of diligent investigation on the rolling bearing, the polyimide resin coating excellent in adhesion and heat resistance does not swell or dissolve even when immersed in a lubricating oil containing a sulfur component. It was found that metal elution into the lubricating oil hardly occurs by forming a polyimide resin film on the surface even with a low metal. For this reason, it is possible to produce a rolling bearing having a coating that is unlikely to elute in an environment where it comes into contact with a lubricating oil containing sulfur components by making a cage having a polyimide resin coating on the surface and attaching this cage. It became.

  The usage aspect of the rolling bearing of this invention is demonstrated based on drawing. FIG. 1 is a longitudinal sectional view of a two-cycle engine using a needle rolling bearing as the rolling bearing of the present invention. As shown in FIG. 1, the two-cycle engine has a piston 8 that performs linear reciprocating motion by combustion of an air-fuel mixture in which gasoline and lubricating oil that is engine oil are mixed, a crankshaft 6 that outputs rotational motion, and a piston 8. Connecting rod 7 and crankshaft 6 and connecting rod 7 for converting linear reciprocating motion into rotational motion. The crankshaft 6 rotates around the rotation center shaft 12 and balances rotation by a balance weight 13.

The connecting rod 7 is formed by providing a large end 15 below the linear rod and a small end 16 above. The crankshaft 6 is rotatably supported via a needle roller bearing 1 a attached to the engagement hole of the large end 15 of the connecting rod 7. The piston pin 14 that connects the piston 8 and the connecting rod 7 is rotatably supported via a needle roller bearing 1 b that is attached to the engagement hole of the small end portion 16 of the connecting rod 7.
The air-fuel mixture obtained by mixing gasoline and lubricating oil is fed into the crank chamber 5 from the intake hole 9 and then guided to the combustion chamber 11 above the cylinder 4 and burned in accordance with the vertical movement of the piston 8. The burned exhaust gas is discharged from the exhaust hole 10.

  FIG. 2 is a perspective view showing a needle roller bearing which is an embodiment of the rolling bearing of the present invention. As shown in FIG. 2, the needle roller bearing 1 includes a plurality of needle rollers 3 and a cage 2 that holds the needle rollers 3 at regular intervals or unequal intervals. The inner ring and the outer ring are not provided, and the shaft such as the crankshaft 6 and the piston pin 14 is directly inserted into the inner diameter side of the cage 3, and the outer diameter side of the cage 3 is fitted into the engagement hole of the connecting rod 7 as a housing. (See FIG. 1). Since the needle roller 3 having no inner and outer rings and having a smaller diameter than the length is used as a rolling element, the needle roller bearing 1 is more compact than a general rolling bearing having inner and outer rings. Become.

The cage 2 is provided with pockets 2a for holding the needle rollers 3, and the intervals between the needle rollers 3 are held by the column portions 2b positioned between the pockets. A polyimide resin film is formed on the surface portion of the cage 2. The surface portion of the cage that forms the resin film is a portion that contacts the lubricating oil, and the entire surface of the cage 2 including the surface of the pocket 2a that contacts the needle roller 3 is preferable.
In addition to the surface portion of the cage 2, a similar resin film can be formed on the surface of the needle roller 3 that is a rolling element or the connecting rod inner diameter surface 7.

  Since the rolling element used for the rolling bearing in the present invention has a roller shape, the rolling bearing of the present invention is attached to the engagement holes provided in the small end portion and the large end portion of the connecting rod, and the piston pin and the crankshaft are mounted. It can be supported and can receive a heavy load despite the small bearing projected area. In particular, a rolling bearing using a highly rigid needle roller as a rolling element can receive a higher load than a rolling bearing using a roller as a rolling element.

The rolling bearing of the present invention supports a crankshaft that outputs rotational motion, and is attached to an engagement hole provided in a large end portion of a connecting rod that converts linear reciprocating motion into rotational motion. Because it is a roller bearing guided by the outer diameter surface, there is almost no peeling of the coating or elution of the metal into the lubricating oil, and the cage can maintain the lubricity for a longer period than conventional metal plating. Wear of the outer diameter surface and the engagement hole inner diameter surface is prevented, and the life of the entire apparatus can be extended.
Further, as shown in FIG. 1, the rolling bearing of the present invention supports a piston pin that outputs a linear reciprocating motion, and an engagement hole provided at a small end portion of a connecting rod that converts the linear reciprocating motion into a rotational motion. It can also be attached to.

  The rolling bearing of the present invention can be applied in an environment where it comes into contact with a lubricating oil containing a sulfur-based additive. For example, as described above, a rolling bearing is attached to a connecting rod of a two-cycle or four-cycle engine, and contacts an air-fuel mixture or engine oil in which gasoline and engine oil are mixed. And the case of contact by lubrication or the like to the cage pocket portion of the rolling bearing.

A sulfur-based additive is an additive containing a sulfur-based compound. Examples of the additive types include antioxidants, rust inhibitors, extreme pressure agents, detergent dispersants, metal deactivators, and antiwear agents. Can be mentioned.
Examples of the lubricating oil to which an additive containing a sulfur compound is added include mineral oil, synthetic oil, ester oil, ether oil and the like.
Examples of the sulfur compounds include thiophosphates such as zinc dialkyldithiophosphate (hereinafter referred to as ZnDTP), zinc diallyldithiophosphate, sulfurized terpene, phenothiazine, mercaptobenzothiazole, petroleum sulfonate, alkylbenzene sulfonate, polybutene. -P ₂ S ₅ reaction product salts, ammonium salts of organic sulfonic acids, alkaline earth metal organic sulfonate, mercapto fatty acids or metal salts thereof such as 1-mercapto stearate, 2,5-dimercapto-1, Thiazoles such as 3,4-thiadiazole, 2-mercaptothiadiazole, disulfide compounds such as 2- (decyldithio) -benzimidazole, 2,5-bis (dodecyldithio) -benzimidazole, dilauryl thiopropionate, etc. Thiocarboxylic acid ester compounds Sulfurized fats and oils such as dibenzyl disulfide, diphenyl disulfide, and sulphated sulfur oil, sulfurized esters such as sulfurized olefins and sulfurized fatty esters, dibenzyl disulfide, alkyl polysulfides, olefin polysulfides, sulfides such as xanthic sulfide, calcium sulfonate, magnesium sulfonate And alkyldithiophosphate amines.
Among the sulfur compounds, a compound that easily affects the roller bearing for connecting rods is ZnDTP.

In the present invention, the phrase “hard to peel or dissolve in an environment in contact with a lubricating oil containing a sulfur-based additive” means, for example, SCM415 having a dimension of 3 mm × 3 mm × 20 mm (surface area 258 mm ² ). When three test pieces having the above-mentioned coating film formed on a base material piece were immersed in 2.2 g of poly-α-olefin containing 1% by weight of ZnDTP at 150 ° C. for 200 hours, the above-mentioned lubricating oil was removed from the test piece. It means that the amount of coating components eluting in is 200 ppm or less in lubricating oil as measured by a fluorescent X-ray measuring device.

The material of the cage used for the rolling bearing is not particularly limited, and iron-based metal materials, copper-based metal materials, aluminum-based metal materials, and resin materials can be used.
Examples of ferrous metal materials include case hardening steel (SCM), cold rolled steel (SPCC), hot rolled steel (SPHC), carbon steel (S25C to S55C), stainless steel (SUS304 to SUS316), mild steel (SS400). Etc. can be used.
As the cage body, bearing steel, carburized steel, or carbon steel for machine structure can be used. Among these, carburized steel having high heat resistance and rigidity capable of withstanding a high load is preferably used. Examples of the carburized steel include SCM415.

Moreover, as a copper-type metal material, a copper-zinc alloy (HBsC1, HBsBE1, BSP1-3), a copper-aluminum-iron alloy (AlBC1), etc., an aluminum-silicon alloy (ADC12) etc. can be used as an aluminum-type metal. .
In addition, resin materials such as polyphenylene sulfide and polyether ether ketone can be used. A resin material containing glass fiber or carbon fiber as a reinforcing material can also be used.

When the composition for a sliding member of the present invention is used as a coating for a rolling bearing cage, the coating can be formed by the following method.
First, a cage as a base formed of an iron-based metal material is sufficiently washed to remove surface contamination. Examples of the cleaning method include immersion cleaning with an organic solvent, ultrasonic cleaning, steam cleaning, acid / alkali cleaning, and the like.
For the purpose of improving the adhesion of the coating, it is possible to perform shot blasting (including shot peening, WPC, etc.), chemical etching, and phosphate coating treatment as pretreatment. The surface roughness of the substrate can be set within a range of Ra = 0.3 or more, and preferably Ra = 0.5 to 1.0. When Ra is less than 0.3, a sufficient anchor effect cannot be obtained, and the adhesion cannot be improved. On the other hand, when the surface roughness of the substrate is large, the finished surface becomes rough. However, if the surface roughness is adjusted to be small by machining such as polishing, it can be used as a cage. Moreover, if Ra = 0.5 to 1.0, it is possible to obtain a small surface roughness without performing sufficient adhesion and machining.
Next, a coating film of the sliding member composition is formed on the cage surface by spray coating, dip coating, electrostatic coating, tumbler coating, electrodeposition coating, or the like. A preferred coating thickness is 1-100 μm, more preferably 1-50 μm. Further, in the process of forming the film, the excessively adhered varnish can be removed by physical and chemical methods such as wiping, centrifuging and air blowing, and adjusted to a desired thickness.
After the formation of the coating, solvent removal, drying, melting, crosslinking, and the like are performed by heat treatment to complete the cage having the coating formed on the surface. When the film thickness is increased, it may be overcoated. It is also possible to perform machining or tumbling after the coating is completed.

The type of the rolling bearing according to the present invention may be either a radial bearing or a thrust bearing. Further, the shape of the rolling element is not particularly limited, but the effect of the present invention can be enjoyed more particularly in the case of the roller shape and the needle roller shape. The roller shape includes a cylindrical roller, a tapered roller, a spherical roller, and the like.
In addition, the rolling bearing according to the present invention can be suitably used for rolling bearings used under lean lubrication conditions, such as the above-mentioned connecting rods and compressors, particularly compressors for air conditioners such as air conditioners and car air conditioners.

The materials used in the examples and comparative examples of the present invention are collectively shown as follows. [] Is an abbreviation shown in Table 1 and Table 2.
(1) Polyamideimide resin varnish [PAI]
Hitachi Chemical Co., Ltd. HPC-5020, Elongation: 70%
(2) Aromatic polyimide resin varnish [PI]
U varnish-A made by Ube Industries
(3) Mixed fullerene [mixed fullerene]
Frontier Carbon's mixed fullerene, C ₆₀ (diameter: 0.71 nm) is about 60 wt%, C ₇₀ (major axis diameter: 0.796 nm, minor axis diameter: 0.712 nm) is about 25 wt% with the balance being higher order fullerene It is a mixture.
(4) Molybdenum disulfide powder [MoS ₂ -0.5 μm]
Nippon Molybdenum M5, average particle size 0.5 μm
(5) Tungsten disulfide powder [WS ₂ -1 μm]
WS2A manufactured by Nippon Lubricant Co., average particle size 1 μm
(6) Polytetrafluoroethylene powder [PTFE-0.3 μm]
KD-1000AS dispersion (solvent: NMP) manufactured by Kitamura Co., Ltd., average particle size 0.3 μm
(7) Graphite powder [graphite-6 μm]
Lonza KS-6, average particle size 6 μm

Example 1, Examples 3-7, Comparative Examples 3-10
Various fillers are mixed with the solid content of polyamideimide resin varnish (solvent: N-methyl-2-pyrrolidone) in the proportions shown in Tables 1 and 2 until they are sufficiently uniformly dispersed by a ball mill, and the mixed solution is rubbed Coating the outer diameter surface of the SUJ2 ring for test [outer diameter 40 mm × inner diameter 20 mm × thickness 10 mm (subcurvature R 60), surface roughness Ra 0.7 μm: 17 in Fig. 3] by shot blasting did. Moreover, the surface of a SPCC square bar (3 mm × 3 mm × 20 mm) was coated by a dipping method for a lubricating oil immersion test. After coating, it was dried at 100 ° C. for 1 hour, further at 150 ° C. for 1 hour, and baked at 250 ° C. for 1 hour. The number of sprays was adjusted so that the film thickness was 20-30 μm. The coating liquid containing fullerene was prepared in advance as a concentrated liquid in which fullerene was dissolved at a 5% concentration in a mixed solvent of toluene and N-methyl-2-pyrrolidone (mixing weight ratio 50:50). The imide resin varnish was prepared by adding to a predetermined concentration. In addition, the mixture ratio of each component of Table 2 and Table 3 is a ratio in solid content, and all are volume%.

A sliding test was performed using the obtained ring-shaped test piece. FIG. 3 is a view showing a sliding tester. 3A shows a front view, and FIG. 3B shows a side view.
The ring-shaped test piece 17 is attached to the rotating shaft 18, and the steel plate 20 is fixed to the air slider 21 of the arm portion 19. The ring-shaped test piece 17 is rotationally brought into contact with the steel plate 20 while applying a predetermined load 22 from the upper side of the drawing, and the lubricating oil is supplied to the outer diameter surface of the ring-shaped test piece 17 from the felt pad 24 impregnated with the lubricating oil. The The frictional force generated when the ring-shaped test piece 17 is rotated is detected by the load cell 23. Further, after a predetermined time, the state of the polyamide-imide resin coating film formed on the outer diameter surface of the ring-shaped test piece 17 is visually: ○: no significant wear and no peeling, Δ: no significant wear, but there is peeling , X: Indicated in three stages of large wear.
The steel plate 20 used was an SCM415 carburized and tempered product (Hv 700, surface roughness Ra 0.01 μm), and the lubricating oil used was Mobile Velocity Oil No. 3 (VG2, manufactured by ExxonMobil Corp.). The load is 50 N, the sliding speed is 5.0 m / s, and the test time is 30 minutes. The coefficient of friction was expressed as an average value for 10 minutes before the end of the test. The results are shown in Table 2 and Table 3.

  Moreover, the lubricating oil immersion test was done using the obtained SPCC square bar. Three 150 ° C. lubricating oil (poly-α-olefin: Lucant HL-10 (manufactured by Mitsui Chemicals) to which 1% by weight of ZnDTP (LUBRIZOL677A, LUBRIZOL) was added) 2.2 g After 200 hours of immersion, the concentration of the coating components eluted in the lubricating oil was measured. The concentration was quantified by fluorescent X-ray measurement [fluorescent X-ray measurement apparatus: Rigaku ZSX100e (manufactured by Rigaku Corporation)]. The results are shown in Table 2 and Table 3.

Example 2
The same method as in Example 1 except that aromatic polyimide resin varnish (solvent: N-methyl-2-pyrrolidone) is used and fullerene is blended in the proportions shown in Table 1 and the firing temperature after coating is 350 ° C. A test piece was prepared and evaluated in the same manner as in Example 1. The results are shown in Table 2.

Comparative Example 1
The same test piece as in Example 1 was subjected to copper plating (plating thickness: 5 μm) as a base by electroplating, and further silver plating (plating thickness: 20 μm) was applied to the surface layer. The obtained test piece was evaluated in the same manner as in Example 1. The results are shown in Table 3.

Comparative Example 2
The same test piece as in Example 1 was subjected to copper plating (plating thickness: 25 μm) by electroplating. The obtained test piece was evaluated in the same manner as in Example 1. The results are shown in Table 3.

FIG. 4 shows a ring surface photograph after the sliding test of Example 5, FIG. 5 shows a ring surface photograph after the sliding test of Comparative Example 3, and FIG. 5 shows a ring surface photograph after the sliding test of Comparative Example 8. 6 respectively.
As is apparent from the results shown in Table 3, in Comparative Example 1 and Comparative Example 2, which are conventionally used metal platings, metal components are eluted in the lubricating oil in the lubricating oil immersion test. In particular, the result was a large amount of copper elution during copper plating. In Comparative Example 3 in which a resin film containing no additive was formed, the friction coefficient was small, but peeling occurred during the friction test (see FIG. 5). Although the comparative example 4 which mix | blended only fullerene did not peel in a friction test, the friction coefficient increased compared with the resin single-piece | unit. In Comparative Example 5 in which polytetrafluoroethylene was blended in addition to fullerene, the friction coefficient was lowered, but peeling occurred. In Comparative Example 6 in which graphite was blended, wear was great. Since Comparative Example 7 has a small amount of fullerene, the peel resistance is not improved. In Comparative Examples 8 and 9, since the blending amount of fullerene or molybdenum disulfide was larger than a predetermined amount, the dispersion was poor, and the amount of wear was increased because the amount of resin as a binder was small and could not hold the additive. In Comparative Example 8, wear marks were observed (see FIG. 6). Further, Comparative Example 10 containing only molybdenum disulfide had almost the same characteristics as the resin alone (Comparative Example 3).

  On the other hand, Examples 1 to 7 shown in Table 2 are polyimide resin films in which a predetermined amount of fullerene and molybdenum disulfide or tungsten disulfide is blended. Therefore, the friction coefficient is low, and peeling during the friction test is remarkable. There was no wear. Neither wear scar nor peeling was observed on the ring surface after the sliding test of Example 5 (see FIG. 4). In the lubricating oil immersion test, no elution of the coating component into the lubricating oil was observed.

  Roller bearing cages are formed with a polyimide resin film containing fullerene and molybdenum disulfide or tungsten disulfide, so there is little friction due to contact between the cage and the bearing ring, and there is no wear or peeling. Less likely to occur, long life and high reliability. Further, the lubricity of the cage can be maintained for a long period of time in an environment in contact with the lubricating oil containing the sulfur-based additive. Therefore, it can utilize suitably for the cage of the rolling bearing used under severe conditions.

It is a longitudinal cross-sectional view of the 2-cycle engine which uses the rolling bearing of this invention. It is a perspective view which shows the needle roller bearing which is one Example of the rolling bearing of this invention. It is a figure which shows a sliding test machine. 6 is a ring surface photograph after a sliding test of Example 5. FIG. 6 is a ring surface photograph after a sliding test of Comparative Example 3. 10 is a ring surface photograph after a sliding test of Comparative Example 8.

Explanation of symbols

1 Needle roller bearings (rolling bearings)
DESCRIPTION OF SYMBOLS 1a Needle roller bearing 1b Needle roller bearing 2 Cage 2a Pocket part 2b Column part 3 Needle roller (rolling element)
4 Cylinder 5 Crank chamber 6 Crankshaft 7 Connecting rod 8 Piston 9 Intake hole 10 Exhaust hole 11 Combustion chamber 12 Rotation center shaft 13 Balance weight 14 Piston pin 15 Large end portion 16 Small end portion 17 Ring-shaped test piece 18 Rotation shaft 19 Arm portion 20 Steel plate 21 Air slider 22 Load 23 Load cell 24 Felt pad

Claims (8)

A composition for a sliding member used for a machine part having at least a surface portion formed of a sliding member,
In the composition, the synthetic resin contains fullerene and at least one disulfide selected from molybdenum disulfide and tungsten disulfide, and the fullerene is contained in an amount of 0.1 to 10 volumes with respect to the entire composition. %, And the disulfide content is 0.5 to 20% by volume.   The sliding member composition according to claim 1, wherein the sliding member formed on the surface portion is a synthetic resin coating.   The composition for a sliding member according to claim 1 or 2, wherein the synthetic resin is a polyimide resin.   A rolling bearing comprising a plurality of rolling elements and a cage for holding the rolling elements, and used in an environment in contact with a lubricating oil containing a sulfur-based additive, or in an atmosphere containing a sulfur-based compound, A rolling bearing according to claim 1, wherein the composition film for a sliding member according to claim 1, 2 or 3 is formed on a surface portion of the cage.   The rolling bearing according to claim 4, wherein the cage is a molded body of an iron-based metal material.   6. A rolling bearing according to claim 4, wherein the rolling element has a roller shape.   The rolling bearing according to claim 6, wherein the roller shape is a needle roller shape. 5. The rolling bearing according to claim 4, wherein the rolling bearing is attached to an engagement hole provided at a large end portion of a connecting rod that supports a crankshaft that outputs rotational motion and converts linear reciprocating motion into rotational motion. Item 8. The rolling bearing according to any one of Items 7.