JP2008286377A - Rolling bearing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rolling bering free from separation of a coating film formed on a surface of a cage and elution of a metallic component, even in use in an environment contacting with lubricating oil including a sulfur-based additive. <P>SOLUTION: This rolling bearing 1 has a plurality of rolling elements 3 and the cage 2 holding these rolling elements 3, and is used in the environment contacting with the lubricating oil including the sulfur-based additive. The cage 2 is characterized in that a polyamide-imide resin coating film having an elongation percentage of 60-120% is formed on a surface part of the cage. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a rolling bearing, and more particularly to a rolling bearing in which a coating that is not affected by a lubricating oil containing a sulfur-based additive is formed on the surface of a cage.

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.
Japanese Patent Laying-Open No. 2005-147306 JP 2002-195266 A

  The present invention has been made to cope with such problems, and even when used in an environment in contact with a lubricating oil containing a sulfur-based additive, peeling of a coating formed on the surface of the cage or metal An object of the present invention is to provide a rolling bearing in which elution of components hardly occurs.

  A rolling bearing according to the present invention is a rolling bearing that 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. The cage is characterized in that a polyamide-imide resin film having an elongation of 60% to 120% is formed on the surface portion of the cage where the lubricating oil contacts.

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 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. It is a roller bearing guided by.

  A rolling bearing according to the present invention is a rolling bearing that includes a plurality of rolling elements and a cage that holds the rolling elements, and is used in an environment that comes into contact with a lubricating oil containing a sulfur-based additive. Since the polyamide-imide resin film having a rate of 60% to 120% is formed on the surface portion of the cage in contact with the lubricating oil, the peeling of the film and the elution of the film components into the lubricating oil can be suppressed. The lubricity of the cage can be maintained for a longer period than metal plating.

  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.

  As a result of intensive studies on rolling bearings that have coatings that are unlikely to elute in an environment where they come into contact with lubricating oil containing sulfur components, polyamideimide resin coatings with excellent adhesion and heat resistance are immersed in lubricating oils containing sulfur components. Even if it is a metal with low sulfidation resistance, it has been found that by forming a polyamideimide resin film on the surface, metal elution into the lubricating oil is unlikely to occur. . The present invention is based on such knowledge.

  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 polyamideimide resin film, which will be described later, 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 coating can be formed on the surface of the needle roller 3 that is a rolling element or the inner diameter surface of the connecting rod 7.

  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. As an environment in contact with the lubricating oil, for example, as described above, an air-fuel mixture in which a rolling bearing is attached to a connecting rod of a two-cycle engine or a four-cycle engine and gasoline and engine oil are mixed, or engine oil is used. And 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 size of 3 mm × 3 mm × 20 mm (surface area 258 mm ² ). When three test pieces having the above-mentioned film formed on a base material piece were immersed in poly-α-olefin (PAO) oil containing 1% by weight of ZnDTP at 150 ° C. for 200 hours, the test piece From the above, the amount of the coating component eluted in the lubricating oil is 200 ppm or less in the lubricating oil as measured by a fluorescent X-ray measuring device.

In the present invention, the polyamideimide resin film formed on the metal surface has an elongation of 60% to 120%, preferably 70% to 110%.
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 or the lubricating oil tends to swell.

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.

The polyamide-imide resin 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. Since the polyamideimide resin that can be used in the present invention has an elongation of 60% or more, 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.

A method disclosed in patent publications such as US Pat. No. 3,625,911 and Japanese Patent Publication No. 50-33120 can be adopted as a method for producing the polyamide-imide resin. For example, aromatic tricarboxylic acid anhydride, aliphatic dicarboxylic acid, and organic diisocyanate are reacted at a predetermined temperature in an organic polar solvent such as dimethylacetamide, dimethylformamide, N-methylpyrrolidone, phenol, cresol, or xylenol for a required time. Can be obtained.
As a commercial item of the polyamideimide resin whose elongation rate of the resin film is 60% to 120%, for example, Hitachi Chemical Co., Ltd .: HPC7200-30 (trade name) can be mentioned.

  The polyamideimide resin film can be formed by the following method. First, the ferrous metal cage used as a base 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.

  Next, a resin film is formed on the surface of the cage by a spray coating method, a dip coating method, or the like. The preferred coating thickness is 1 μm to 100 μm, more preferably 5 μm to 50 μm. When the thickness of the coating is less than 1 μm, the durability is insufficient, and when it exceeds 100 μm, the roundness of the cage deteriorates.

  Since the rolling bearing of the present invention uses a cage having a polyamideimide resin film formed on the surface thereof by post-processing, bearing steel, carburized steel, or carbon steel for mechanical structure can be used as the cage body. Among these, it is preferable to use carburized steel having high heat resistance and rigidity capable of withstanding high loads. Examples of the carburized steel include SCM415.

  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.

Example 1
Polyamideimide resin varnish is applied to the outer surface of SUJ ring with outer diameter 40 mm × inner diameter 20 mm × thickness 10 mm (sub-curvature R 60), and then dried to form a polyamideimide resin coating with a thickness of 20-30 μm. Formed with. The polyamide-imide resin varnish used was HPC7200-30 with an elongation of 101%. The conditions for forming the coating film were predrying at 80 ° C for 30 minutes, then 150 ° C for 10 minutes, and finally drying at 200 ° C for 30 minutes. . The sliding test shown below was performed using the obtained ring-shaped test piece. The results are shown in Table 1.

<Sliding test>
The sliding tester (Sabang type friction and wear tester) shown in FIG. 3 was used. 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 a predetermined load 22 is applied from above in the drawing, and the lubricating oil is supplied to the outer peripheral surface of the ring-shaped test piece 17 from the felt pad 24 impregnated with the lubricating oil. 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 elapsed, the number of portions where the polyamideimide resin coating film formed on the outer peripheral surface of the ring-shaped test piece 17 was peeled was visually measured as the number of peel points.
The steel plate 20 was an SCM415 carburized and tempered product (Hv 700), and the lubricating oil was Mobil Velocity Oil No. 3 (Exxon Mobil Corp .: VG2). The load is 50 N, the sliding speed is 5 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.

Comparative Example 1
As the polyamideimide resin varnish, HPC4250-30 having an elongation of 14% was used. The film formation conditions on the ring-shaped test piece were 80 ° C for 30 minutes, followed by predrying at 150 ° C for 10 minutes, and finally drying at 180 ° C for 60 minutes to form a polyamideimide resin film with a thickness of 20-30 μm. Formed with. A sliding test was conducted in the same manner as in Example 1 except that this ring-shaped test piece was used. The results are shown in Table 1.

Comparative Example 2
A film was formed under the same conditions as in Comparative Example 1 except that HPC9000-21 having an elongation of 10% was used as the polyamideimide resin varnish, and a sliding test was performed under the same measurement conditions. The results are shown in Table 1.

伸び率が大きいポリアミドイミド樹脂被膜（実施例１）は剥離点数が少ない、すなわち摺動面の損傷が少ないため摩擦係数も小さくなっている。伸び率が小さいポリアミドイミド樹脂被膜（比較例１、２）は剥離点数が多く、摺動面が損傷し粗さが大きくなるため摩擦係数が実施例１よりも大きくなっている。

The polyamideimide resin coating (Example 1) having a large elongation has a small number of peeling points, that is, a small friction coefficient because the sliding surface is less damaged. The polyamideimide resin coating film (Comparative Examples 1 and 2) having a small elongation rate has a large number of peeling points, and the sliding surface is damaged and the roughness is increased. Therefore, the friction coefficient is larger than that of Example 1.

Example 2
In order to evaluate the chemical stability of the polyamideimide resin coating, a lubricating oil immersion test was conducted.
A coating composed of polyamideimide resin (90% by volume) and MoS ₂ (10% by volume) on the entire surface of three SCM415 substrate pieces having dimensions of 3 mm × 3 mm × 20 mm (surface area 258 mm ² ). A test piece was formed. The polyamide-imide resin varnish is HPC7200-30 used in Example 1. The conditions for coating film formation were 80 ° C. for 30 minutes, followed by preliminary drying at 150 ° C. for 10 minutes, and finally drying at 200 ° C. for 30 minutes. The film was μm thick. As MoS ₂ , Nichimori A powder (trade name) manufactured by Daizo Co., Ltd. was added as a detection element when the film was eluted. This test piece was subjected to the lubricating oil immersion test shown below, and the amount of the coating component eluted in the lubricating oil was measured. The results are shown in Table 2.

<Lubricating oil immersion test>
Test was conducted when 3 test pieces were immersed in 150 g of PAO oil (Mitsui Chemicals: Lucant HC-10) containing 1% by weight of ZnDTP (LUBRIZOL: LUBRIZOL677A) for 200 hours. The amount of coating component eluted from the piece into the lubricating oil is measured using a fluorescent X-ray measurement apparatus (Rigaku ZSX100e, manufactured by Rigaku Corporation).

Comparative Example 3
Three SCM415 substrate pieces having dimensions of 3 mm × 3 mm × 20 mm (surface area 258 mm ² ) were subjected to copper plating to form a 30 μm copper film, thereby obtaining test pieces. The test piece was subjected to the same measurement as in Example 2. The results are shown in Table 2.

Comparative Example 4
Three SCM415 substrate pieces with dimensions of 3 mm x 3 mm x 20 mm (surface area 258 mm ² ) were subjected to copper plating treatment to form a 5 µm copper film as an undercoat, and then silver plating treatment to 25 µm A silver film was formed to obtain a test piece. The test piece was subjected to the same measurement as in Example 2. The results are shown in Table 2.

伸び率が大きいポリアミドイミド樹脂被膜を用いることにより、金属の溶出量がなく化学的に安定した被膜が得られる。
表１および表２の結果から、伸び率が大きいポリアミドイミド樹脂被膜は耐剥離性を備えた被膜を得ることができ、保持器は潤滑性をより長期間維持することができる。

By using a polyamide-imide resin film having a high elongation rate, a chemically stable film without a metal elution amount can be obtained.
From the results of Tables 1 and 2, a polyamideimide resin film having a high elongation can provide a film having peeling resistance, and the cage can maintain lubricity for a longer period.

  The rolling bearing of the present invention is provided with a polyamideimide resin film having a high elongation rate on the cage surface, so that the lubricity of the cage can be maintained for a long time in an environment in contact with a lubricating oil containing a sulfur-based additive. And can be suitably used as a rolling bearing used in this environment.

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.

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 (5)

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,
The rolling bearing is characterized in that a polyamide-imide resin film having an elongation rate of 60% to 120% is formed on a surface portion of the cage in contact with the lubricating oil.   The rolling bearing according to claim 1, wherein the cage is a molded body of an iron-based metal material.   The rolling bearing according to claim 1, wherein the rolling element has a roller shape.   The rolling bearing according to claim 3, wherein the roller shape is a needle roller shape.   The rolling bearing is attached to an engagement hole provided at a large end of a connecting rod that supports a crankshaft that outputs rotational motion and converts linear reciprocating motion into rotational motion, and is guided by an outer diameter surface of the cage. The rolling bearing according to any one of claims 1 to 4, wherein the roller bearing is a roller bearing.

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