JP2015113457A - Lubrication film and slide bearing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lubrication film which has high adhesion strength, excellent seizure resistance under a high PV and thin lubrication condition, and low friction and low abrasion characteristics, and which rarely causes exposure of foundation even when it is locally abraded by tilting of a sliding mating member, and to provide a slide bearing having the lubrication film formed.SOLUTION: The slide bearing 1 comprises a metal plate 2 and a lubrication film 3 formed on the surface of the metal plate 2. The lubrication film 3 is a coating film containing a PAI resin as a matrix resin and being formed of a composition containing the PAI resin, at least one solid lubricant selected from a fluorine resin and graphite, and a carbon fiber having a fiber diameter of 5 to 15 μm and an average fiber length of 20 to 100 μm. Film thickness of the lubrication film is 3 to 15 times the fiber diameter of the carbon fiber.

Description

  The present invention relates to a lubricating coating containing a polyamideimide resin as a matrix resin and containing carbon fibers, and a sliding bearing formed by forming this lubricating coating.

  Replacement of metal rolling bearings is advancing in thrust bearings for compressors for room air conditioners and car air conditioners, and transmissions for automobiles and construction machinery. In the above applications, there is a case where it is used under the condition of high PV (PV: product of surface pressure (P) and sliding speed (V)) and insufficient lubrication and lean lubrication. Since simple resin bearings have low frictional heat dissipation, there has been a problem that they melt and wear due to frictional heat generation and seizure under dilute lubrication. Moreover, the load resistance at the time of use under high temperature and high pressure was insufficient.

  For this reason, as a substitute for the above-mentioned metal rolling bearing, a sliding bearing has been proposed in which a lubricating coating using a polyamideimide (hereinafter referred to as PAI) resin as a matrix resin is formed on the surface of a metal substrate. Since this plain bearing is a thin film having a film thickness of about 10 to 20 μm, it has excellent frictional heat dissipation and load resistance. The PAI resin has a very high heat resistance as compared with other matrix resins such as a phenol resin and an epoxy resin used for the lubricating coating. Moreover, a low friction characteristic can be provided by mix | blending solid lubricants, such as polytetrafluoroethylene (henceforth PTFE) resin, graphite, molybdenum disulfide.

  In addition, in order to improve the wear resistance at high PV, a lubricating coating in which a solid lubricant and an antiwear agent are blended with a PAI resin has been proposed (see Patent Document 1). Here, examples of the antiwear agent include granular antiwear agents such as alumina, silicon nitride, boron nitride, and silica, potassium titanate fibers, and carbon fibers. Similarly, for the purpose of improving wear resistance, it has also been proposed to blend a fibrous filler of a nanocarbon material into PAI resin or the like (see Patent Document 2).

JP 2002-53883 A JP 2012-246863 A

  However, in the lubricating coating described in Patent Document 1, the particulate antiwear agent is insufficient in imparting wear resistance under lubrication in which oil is diluted. Since the potassium titanate fiber is a very short fiber with a fiber diameter of 0.5 μm and a fiber length of 15 μm, the reinforcing effect of the PAI resin is poor. Carbon fibers are larger than potassium titanate fibers, but generally have a fiber diameter of about 5 to 20 μm, which is 1 to 2 times larger than the thickness of the lubricating coating of 10 to 20 μm. For this reason, not only does the adhesion between the base material and the coating film be disturbed, but the carbon fibers are likely to fall off due to sliding, and conversely, the wear resistance may be reduced.

  Further, since the nanocarbon material of Patent Document 2 is a microfiber having a fiber diameter of 150 nm or less and a fiber length of 8 μm or less, it has a poor PAI reinforcing effect like the potassium titanate fiber. Further, since the lubricating coating is as thin as about 10 to 20 μm, the tilt when the sliding contact surface with the mating member is slightly tilted cannot be allowed due to the dimensional accuracy of the peripheral mounting parts. For example, if it is tilted by 10 μm, even if the coating is locally worn by 10 μm during sliding contact and the contact becomes uniform, the base is exposed as soon as it wears, so that the wear life is insufficient.

  The present invention has been made to address such problems, and is a high adhesion strength coating that has excellent seizure resistance under conditions of high PV and lean lubrication, and has low friction and low wear characteristics. It is another object of the present invention to provide a lubricating coating that hardly causes base exposure even if it is locally worn due to the inclination of a mating member that is in sliding contact, and a sliding bearing formed with the lubricating coating.

  The lubricating coating of the present invention is a lubricating coating formed on a sliding surface with a counterpart material using a PAI resin as a matrix resin, and the lubricating coating is at least one selected from the PAI resin, a fluororesin, and graphite. It is a coating film made of a composition containing two solid lubricants and carbon fibers having a fiber diameter of 5 to 15 μm and an average fiber length of 20 to 100 μm, and the film thickness of the lubricating coating is the fiber diameter of the carbon fibers. 3 to 15 times.

  The lubricating coating contains 10 to 150 parts by weight of the solid lubricant and 3 to 50 parts by weight of the carbon fiber with respect to 100 parts by weight of the PAI resin. The lubricating coating has a thickness of 30 to 100 μm.

  The solid lubricant contains at least the fluororesin, and the fluororesin is a PTFE resin. Further, the solid lubricant includes the graphite, and the graphite is artificial graphite having 97.5% or more of fixed carbon.

  The lubricating coating is formed by dispenser coating and then polishing the surface of the counterpart material.

  The sliding bearing of the present invention is a sliding bearing having a metal substrate and a lubricating coating formed on the surface of the metallic substrate, wherein the lubricating coating is the lubricating coating of the present invention. The sliding bearing is a bearing whose sliding surface is lubricated with oil or grease.

  The lubricating coating of the present invention is a lubricating coating formed on a sliding surface with a mating material using a PAI resin as a matrix resin, at least one solid lubricant selected from PAI resin, fluororesin and graphite, and fiber Carbon fiber having a diameter of 5 to 15 μm and an average fiber length of 20 to 100 μm, and a film thickness of 3 to 15 times the fiber diameter of the carbon fiber. Is difficult to drop off from the lubricating coating and does not hinder the adhesion between the substrate and the coating, so even under conditions of high PV and insufficient lubricating oil supply and lean lubrication, low friction and low wear characteristics, No seizure occurs.

  Since the lubricant film contains 10 to 150 parts by weight of the solid lubricant and 3 to 50 parts by weight of the carbon fiber with respect to 100 parts by weight of the PAI resin, the friction characteristics, wear resistance, elastic modulus and the like of the lubricant film Especially excellent in strength. Moreover, since it is the lubricating film which consists of this mixing | blending, even when a film thickness is 30-100 micrometers thick, a limit PV value is high and it is excellent in abrasion resistance.

  Since the lubricating film has a thickness of 30 to 100 μm and is a thick film, a slight inclination of the sliding contact surface of the mating member is compatible with initial wear, and local exposure of the base metal can be eliminated.

  Since the solid lubricant contains at least a fluororesin and the fluororesin is a PTFE resin, there is no seizure under the conditions of high PV and lean lubrication, and the low friction characteristics can be further improved. In addition, since the solid lubricant includes graphite and the graphite is artificial graphite having 97.5% or more of fixed carbon, it can impart low friction characteristics under oil lubrication to the lubricating coating, and at the same time, wear resistance, elasticity Rate and strength can be imparted.

  The sliding bearing of the present invention is formed by forming the lubricating coating of the present invention on the surface of the metal base material, and therefore has a high limit PV value and seizure resistance, and has a low friction and low wear characteristic. Further, it is suitable as a liquid lubrication bearing whose sliding surface is lubricated with oil or grease.

It is a perspective view of the sliding bearing (thrust sliding bearing) of this invention.

  The lubricating coating of the present invention is formed on a sliding surface with a mating material using a PAI resin as a matrix resin, and at least one solid lubricant selected from (1) PAI resin, (2) fluororesin and graphite. It is the coating film formed from the composition containing an agent and (3) carbon fiber of a predetermined shape. Moreover, the film thickness of this lubricating coating is 3 to 15 times the fiber diameter of the carbon fiber. Hereinafter, this lubricating coating will be described in detail.

  The lubricating coating of the present invention uses PAI resin as the matrix resin. The PAI resin is a resin having an imide bond and an amide bond in the polymer main chain. Among the PAI resins, an aromatic PAI resin in which an imide bond and an amide bond are bonded via an aromatic group is preferable. When it is an aromatic PAI resin, it is excellent in the binding property with the metal base material as a base, and the heat resistance of the resulting lubricating coating is particularly excellent. Here, the imide bond of the aromatic PAI resin may be a precursor such as polyamic acid, a closed imide ring, or a state in which they are mixed.

  Such aromatic PAI resins include PAI resins produced from aromatic primary diamines such as diphenylmethanediamine and aromatic tribasic acid anhydrides, such as mono- or diacyl halide derivatives of trimellitic acid anhydride, aromatic There are PAI resins produced from tribasic acid anhydrides and aromatic diisocyanate compounds such as diphenylmethane diisocyanate. Furthermore, as a PAI resin having a larger ratio of imide bonds than amide bonds, it is produced from aromatic, aliphatic or alicyclic diisocyanate compounds and aromatic tetrabasic acid dianhydrides and aromatic tribasic acid anhydrides. Any PAI resin can be used.

Any fluororesin can be used as long as it can impart low friction properties to the lubricating coating and has heat resistance that can withstand the operating temperature atmosphere of the coating. Examples of the fluororesin include PTFE resin, tetrafluoroethylene-perfluoroalkyl vinyl ether (PFA) copolymer resin, tetrafluoroethylene-hexafluoropropylene (FEP) copolymer resin, and tetrafluoroethylene-ethylene (ETFE) copolymer. Polymer resin etc. are mentioned. Among these, it is preferable to use PTFE resin powder. PTFE resin has a high melt viscosity of about 10 ¹⁰ to 10 ¹¹ Pa · s at about 340 to 380 ° C., hardly flows even when the melting point is exceeded, has the highest heat resistance among fluororesins, and is excellent even at low temperatures It exhibits properties and excellent friction and wear characteristics.

The PTFE _{resin, - (CF 2 -CF 2)} n- in can be used ordinary PTFE resin represented, also generally of PTFE resin perfluoroalkyl ether group _{(-C p} F 2p -O- ) (P is an integer of 1-4) or a modified PTFE resin into which a polyfluoroalkyl group (H (CF ₂ ) _q- ) (q is an integer of 1-20) or the like is introduced. These PTFE resins and modified PTFE resins may be obtained by employing either a suspension polymerization method for obtaining a general molding powder or an emulsion polymerization method for obtaining a fine powder.

  The average particle diameter (measured value by laser analysis method) of the PTFE resin powder is not particularly limited, but is preferably 20 μm or less in view of the strength and wear resistance of the lubricating coating.

  As the PTFE resin powder, a PTFE resin obtained by heating and baking at a melting point or higher can be used. Further, a powder obtained by further irradiating a heat-fired powder with γ rays or electron beams can also be used. These PTFE resin powders were formed with excellent uniform dispersibility in a resin coating that forms a lubricating coating (coating film) as compared with PTFE resins (molding powder, fine powder) that were not heated and fired. The wear resistance of the lubricating coating is excellent.

  Graphite has excellent properties as a solid lubricant. Graphite is roughly classified into natural graphite and artificial graphite. The shape includes flakes, granules, and spheres, but any of them can be used. Artificial graphite is generally not suitable for lubricants because it is difficult to make graphite with sufficiently advanced graphitization because it is difficult to make artificial graphite because it is carborundum produced during the manufacturing process. . Since natural graphite is produced that is completely graphitized, it has very high lubricating properties and is suitable as a solid lubricant. However, since the impurity contains a lot of impurities and this impurity lowers the lubricity, the impurities must be removed, but it is difficult to completely remove them.

  As the graphite, graphite having 97.5% or more of fixed carbon is preferably used, and artificial graphite having 98.5% or more of fixed carbon is more preferable. Such graphite has high compatibility with the lubricating oil, and even if the lubricating oil does not adhere to the surface, the lubricating property is maintained by the lubricating oil impregnated in a trace amount in the graphite.

  The average particle diameter of graphite (measured by a laser analysis method) is not particularly limited, but is preferably 20 μm or less in view of the strength and wear resistance of the lubricating coating.

  As the shape of the carbon fiber, one having the following fiber diameter and average fiber length is used. The fiber diameter of the carbon fiber is 5 to 15 μm. A thick carbon fiber exceeding this range reduces the strength of the lubricating coating, and the carbon fiber tends to fall off. On the other hand, if the fiber diameter is less than 5 μm, the effect of reinforcing the coating is poor, the wear resistance is poor, and a high limit PV value cannot be obtained. A more preferable fiber diameter is 5 to 10 μm. In addition, about a fiber diameter, the fiber diameter of a carbon fiber base yarn should just be in the said range.

  The average fiber length of the carbon fiber is 20 to 100 μm. If the average fiber length is less than 20 μm, a sufficient reinforcing effect cannot be obtained and the load resistance and wear resistance are poor. When the average fiber length exceeds 100 μm, the uniformity of the strength of the lubricating coating is lowered, and the ratio of carbon fibers on the friction surface is lowered, so that the wear resistance is lowered. Moreover, it becomes a factor which inhibits the adhesive force of a base material and a film. A more preferable average fiber length is 20 to 60 μm. In addition, the average fiber length in this invention is a number average fiber length.

  The type of carbon fiber is not limited as long as the above shape can be satisfied, and may be any of pitch type or PAN type classified from raw materials. Among these, PAN-based carbon fibers having a high elastic modulus are preferable. The firing temperature is not particularly limited, but a carbonized product fired at about 1000 to 1500 ° C. is higher than that fired at a high temperature of 2000 ° C. or higher and converted to graphite (graphite). Even under PV, it is preferable because the mating material is hardly damaged by wear. By using PAN-based carbon fiber as the carbon fiber, the elastic modulus of the resin coating is increased, and the deformation and wear of the coating are reduced. Furthermore, the true contact area of the friction surface is reduced, and frictional heat generation is reduced.

  Commercially available carbon fibers that can be used in the present invention include Kureha Kureka M-2007S as pitch-based carbon fibers, Toho Tenax's Best Fight HTA-CMF0040-0H as PAN-based carbon fibers, and Torayca MLD-30 from Toray. Etc.

  In the resin composition for forming the lubricating coating of the present invention, it is preferable that at least one solid lubricant selected from fluororesin and graphite is blended in an amount of 10 to 150 parts by weight based on 100 parts by weight of the PAI resin. That is, as a solid lubricant, when (1) the fluororesin is used alone, the fluororesin is 10 to 150 parts by weight with respect to 100 parts by weight of the PAI resin, and (2) when the graphite is used alone, the graphite Is 10 to 150 parts by weight with respect to 100 parts by weight of the PAI resin. (3) When the fluororesin and graphite are used in combination, the total amount of the fluororesin and the graphite is 100 parts by weight of the PAI resin. 10 to 150 parts by weight.

  Fluororesin is used for the purpose of imparting low friction properties under dilute lubrication and prevention of seizure, and graphite is used for the purpose of imparting low friction properties under oil lubrication, wear resistance, strength of the lubricating coating, and elastic modulus. Mix each one. When the blending amount of the fluororesin is less than 10 parts by weight with respect to 100 parts by weight of the PAI resin, the low friction property is inferior, and there is a possibility that wear promotion and seizure occur due to heat generation. On the other hand, when the blending amount of the fluororesin exceeds 150 parts by weight, the low friction property is excellent, but the coating strength and wear resistance property may be deteriorated.

  If the compounding amount of graphite is less than 10 parts by weight with respect to 100 parts by weight of PAI resin, there is a possibility that the effect of modifying the frictional wear characteristics and the strength and elastic modulus of the lubricating coating when graphite is blended may not be obtained. . On the other hand, if the blending amount of graphite exceeds 150 parts by weight, the strength of the lubricating coating is lowered, the wear resistance is lowered, the adhesion of the lubricating coating is impaired, and peeling may occur.

  In order to obtain a low-friction property under lean lubrication and oil lubrication, and to obtain a lubricating film with a high safety factor that is hardly affected by the state of lubrication, a fluorine resin and graphite are used in combination as a solid lubricant. Is preferred. In this case, it is more preferable that the resin composition for forming the lubricating coating contains 50 to 100 parts by weight of fluororesin and 5 to 30 parts by weight of graphite with respect to 100 parts by weight of PAI resin.

  In the resin composition for forming the lubricating coating of the present invention, the predetermined carbon fiber is preferably blended in an amount of 3 to 50 parts by weight with respect to 100 parts by weight of the PAI resin. Carbon fiber is blended for the purpose of imparting abrasion resistance, coating strength, and elastic modulus, and its effect is higher than that of graphite. If the blending amount of the carbon fiber is less than 3 parts by weight with respect to 100 parts by weight of the PAI resin, there is a possibility that the effect of improving the wear resistance and the strength and elastic modulus of the lubricating coating cannot be obtained. On the other hand, when the blending amount of the carbon fiber exceeds 50 parts by weight, the strength of the lubricating coating is lowered and the wear resistance may be lowered. When combined with graphite, carbon fiber plays a role of macro-reinforcement and graphite as micro-reinforcement for wear resistance, lubrication film strength, and elasticity. It is done.

  The film thickness of the lubricating coating of the present invention is 3 to 15 times the fiber diameter of the carbon fiber. Since the fiber diameter of the carbon fiber is 5 to 15 μm as described above, the film thickness is specifically 15 to 225 μm. The thinner the lubricant film, the higher the load resistance and frictional heat dissipation, and the higher limit PV and the better the wear resistance. However, if the film thickness is as thin as less than 3 times the fiber diameter of the carbon fiber, the carbon fiber is likely to drop off, and the strength of the lubricating coating also decreases. On the other hand, if it exceeds 15 times, the load resistance and frictional heat dissipation of the lubricating coating are lowered, and the wear resistance is inferior. The lubricating coating of the present invention uses a PAI resin as a matrix resin, and is a thick coating as a lubricating coating formed on a sliding surface, etc., and has a carbon size that can provide a sufficient reinforcing effect in the coating. The thick film is used in order to include the fiber.

  The film thickness of the lubricating coating is preferably 30 to 100 μm. By making the film thickness 3 to 15 times the fiber diameter of the carbon fiber and 30 to 100 μm, the load resistance and frictional heat dissipation are high, the high limit PV is excellent in wear resistance, and the sliding contact of the counterpart material If the surface has a slight inclination, the remaining film thickness after the initial wear can be secured, and local exposure of the underlying metal can be eliminated.

  In addition to the above PAI resin, fluororesin, graphite, and carbon fiber, the resin composition for forming the lubricating coating of the present invention contains other additives such as pigments as long as the necessary characteristics of the present invention are not reduced. May be included. Moreover, it is preferable that carbon fiber other than the said predetermined shape carbon fiber, and other fibrous reinforcements, such as glass fiber and a whisker, are not included from the point of being lacking in a reinforcement effect and being liable to fall off. Most preferably, as shown in the examples described later, it is composed of three components of PAI resin, fluororesin, and carbon fiber of a predetermined shape, or composed of four components obtained by adding graphite to this. .

  The lubricating coating (coating film) of the present invention is formed by a coating method such as spraying, dispenser, screen printing, roll coating, etc., using a resin coating comprising the above resin composition. This resin coating is obtained by dispersing or dissolving solid PAI resin, fluororesin, graphite, and carbon fiber in a solvent at the above-described blending ratio. Solvents include ketones such as acetone and methyl ethyl ketone, esters such as methyl acetate and ethyl acetate, aromatic hydrocarbons such as toluene and xylene, and organic halogenated compounds such as methyl chloroform, trichloroethylene, and trichlorotrifluoroethane. And aprotic polar solvents such as N-methyl-2-pyrrolidone (NMP), methylisopyrrolidone (MIP), dimethylformamide (DMF), and dimethylacetamide (DMAC). These solvents can be used alone or as a mixture. According to the coating method, the type of solvent and the liquid viscosity may be adjusted.

  In the lubricating coating of the present invention, since the above-mentioned carbon fiber is blended, in consideration of non-uniformity of the coating film composition resulting from the precipitation of the carbon fiber in the resin paint and the coating method, rather than spray coating, Dispensers, screen printing and roll coating are suitable. In particular, by adopting dispenser coating, there is no waste of paint, and a thick lubricating film can be easily formed in a short time. After the resin paint is applied to the base material, it is baked to obtain a cured and adhered lubricating film.

  About the film thickness range of the above-mentioned lubricating coating, the film thickness after baking may be set to a predetermined range, or the film thickness after baking may be formed to be thicker and may be set to a predetermined range by machining such as polishing. In order to increase the flatness of the sliding surface, achieve a stable boundary lubrication state with the lubricant, and stabilize the frictional wear characteristics in the boundary lubrication state even when the lubricant is depleted, It is preferable to form a thick film and to obtain a predetermined film thickness by machining such as polishing. In addition, since the lubricating coating of the present invention is thick, by adjusting the film thickness by post-processing, even if the accuracy of the flatness on the substrate side is inferior, this is absorbed on the lubricating coating, Since the accuracy of flatness can be ensured, it is not necessary to process the substrate itself with high accuracy.

  An example of the sliding bearing of the present invention will be described with reference to FIG. FIG. 1 is a perspective view of a thrust slide bearing. The sliding bearing 1 is composed of a metal plate 2 serving as a base substrate and a lubricating coating 3 formed on a sliding surface of the metal plate 2 with a mating member. This lubricating coating 3 is the lubricating coating of the present invention.

  By using a sliding bearing in which the lubricating coating is formed on the surface of a metal substrate such as a metal plate, the bearing has low friction and low wear characteristics and a high limit PV value even under oil lubrication and lean lubrication. Further, a slight inclination of the sliding contact surface with the counterpart material is acceptable, and can be used without exposing the base and peeling off the lubricating coating.

  Any metal material can be adopted as the material of the metal substrate. For example, by adopting iron, aluminum, aluminum alloy, copper, copper alloy, etc., the required thermal conductivity and load resistance can be ensured, and heat is released from the resin coating to the metal substrate and from the metal substrate to the outside. Easy to use and can be used even under high loads. Examples of iron include general structural carbon steel (SS400, etc.), mild steel (SPCC, SPCE, etc.), stainless steel (SUS304, SUS316, etc.), and these irons may be plated with zinc, nickel, copper, or the like. . Examples of aluminum include A1100 and A1050, examples of aluminum alloys include A2017 and A5052 (including anodized products), examples of copper include C1100, and examples of copper alloys include C2700 and C2801.

  In order to improve the adhesion with the coating film, the surface on which the lubricant film is formed on the metal substrate should be roughened by shot blasting, tumbling, machining, etc., or subjected to chemical surface treatment to form a fine uneven shape. Is preferred.

  Since the sliding bearing of the present invention is composed of the above lubricating coating and a metal substrate, it has high load resistance, friction heat dissipation, low friction and low wear characteristics, seizure resistance, and critical PV characteristics under lubrication with oil or grease. It becomes a bearing for liquid lubrication. Examples of the sliding bearing include a thrust sliding bearing in which a lubricating coating is formed on the surface of a flat plate such as a metal disk as shown in FIG. 1 and a radial sliding bearing in which a lubricating coating is formed on a cylindrical inner diameter surface. Examples of the application of the lubricating coating of the present invention include pins and pistons having a lubricating coating formed on a cylindrical outer diameter surface.

Examples 1 to 8 and Comparative Examples 3 to 8
A disk-shaped S45C (outer diameter φ90 mm, thickness 6 mm) polished after lathe was used as a metal substrate, and shot blasting (target Rz 5.0 μm) was performed to increase the surface roughness. On one side of the metal base material, the resin paints ((a) to (l)) having the composition shown in Tables 1 and 2 are applied as solids so as to be 50 to 120 μm after firing with a dispenser coating, and fired at 240 ° C. Later, it was polished to a flatness of 15 μm or less and a film thickness of 30 to 100 μm to obtain a test piece.

Comparative Example 1
A metal substrate was processed in the same manner as in Example 1. The resin paint (a) having the composition shown in Table 2 as a solid content was applied so as to be about 40 μm after firing with a dispenser coating, and was ground at a flatness of 15 μm or less and a film thickness of 15 μm after firing at 240 ° C. Got a piece

Comparative Example 2
A metal substrate was processed in the same manner as in Example 1. The resin paint (a) having the composition shown in Table 2 as a solid content is applied to a thickness of about 150 μm after firing with a dispenser coating, and is ground at a flatness of 15 μm or less and a thickness of 140 μm after firing at 240 ° C. Got a piece

The raw materials for the lubricating coating used in the examples and comparative examples are collectively shown below. As the resin paint, a PAI resin varnish in which a PAI resin was dispersed in N-methylpyrrolidone was used, and a viscosity was adjusted by adding a filler to the varnish and diluting it.
(1) PAI: Glass transition temperature 245 ° C product (aromatic PAI resin)
(2) PTFE: PTFE resin (average particle size 10 μm, heat-fired type)
(3) Graphite: Artificial graphite (average particle size 10 μm)
(4) CF-1: PAN-based carbon fiber (fiber diameter 7 μm, average fiber length 30 μm)
(5) CF-2: PAN-based carbon fiber (fiber diameter 7 μm, average fiber length 130 μm)
(6) CF-3: pitch-based carbon fiber (fiber diameter 18 μm, average fiber length 130 μm)
(7) Whisker: Potassium titanate whisker (fiber diameter 0.3 to 0.6 μm, fiber length 10 to 20 μm)
(8) Inorganic powder: Alumina (average particle size 8μm)
(9) GF: Glass fiber (fiber diameter 10 μm, average fiber length 30 μm)

<Friction test>
Friction and wear test using a thrust type tester (3 shoe-on-type) that slides three steel shoes (SUJ2, φ13 mm (effective sliding part)) for each test piece of Example and Comparative Example And the coefficient of friction after 60 minutes was measured. The test conditions are as follows. The results are shown in Tables 1 and 2.
Load: 400N
Sliding speed: 32m / min
Lubrication condition: Dry Test time: 60 minutes

<Limit surface pressure test>
The critical surface pressure was confirmed using the same thrust type testing machine (3-shoe on type) as the frictional wear test. The test conditions are as follows. The surface pressure immediately before the surface pressure at which the substrate exposure including the sudden fluctuation of the friction coefficient and the local exposure occurred was defined as the limit surface pressure (MPa). Judgment is made as the proof strength to the extreme pressure state by the piece of shoe that comes into sliding contact. The results are shown in Tables 1 and 2.
Surface pressure: Additional 1MPa per hour from 8MPa Sliding speed: 25m / sec
Lubrication conditions: in refrigeration oil (100 ° C, with circulation)

<Tensile shear test>
In order to measure the film strength, the sliding surfaces of the test pieces of Examples and Comparative Examples were surface-treated with a surface treatment agent (Tetra H), and SPCC steel (SS400, 15 × 45 × 2 mm) and epoxy-based two-liquid adhesion Adhesion was performed using an agent. The bonding condition was that the test piece was fixed at 0.5 MPa, placed in an electric furnace as it was, and left to cure at 110 ° C. for 45 minutes. The adhesion area is 2 cm ² . About each obtained test piece, the metal plate was pulled at the speed | rate of 5 mm / min with the tension tester (Shimadzu Corporation autograph), and the tensile shear bond strength (MPa) was measured. The results are shown in Tables 1 and 2.

  In Examples, the coefficient of friction was low, the critical surface pressure was as high as 12 MPa or more, and a balance with the adhesion strength of the coating was also ensured. On the other hand, in Comparative Example 1 in which the film thickness was less than 3 times the fiber diameter of the carbon fiber, the carbon fiber dropped out and the limit surface pressure was low. Since the comparative example 2 whose film thickness exceeds 15 times the fiber diameter of the carbon fiber is inferior in frictional heat dissipation, the critical surface pressure is low. In Comparative Examples 3 to 8, in which an inorganic compounding agent other than carbon fiber or a carbon fiber other than a predetermined shape was blended in the coating, the limit surface pressure did not reach 10 MPa. In Comparative Example 8 using a glass fiber having the same shape as the carbon fiber in the present invention, the friction coefficient was large and the critical surface pressure was low.

  From the above results, the lubricating coating and the multi-layer bearing according to the present invention have a sufficient balance of high limit surface pressure, low friction characteristics, wear resistance, and adhesion strength of the coating, and the supply of lubricating oil is insufficient. It can be seen that even when lubrication occurs, the frictional heat dissipation is high and seizure does not occur.

  Sliding bearings with a lubricating coating of the present invention can satisfy a good balance of low friction properties, wear resistance properties, and coating adhesion strength, so they can be used under oil lubrication, such as thrust receivers for compressors, transmissions, and hydraulic pumps. It can be suitably used as a bearing.

1 Sliding bearing 2 Metal plate 3 Lubrication coating

Claims (8)

A polyamideimide resin as a matrix resin, a lubricating film formed on a sliding surface with a counterpart material,
The lubricating coating comprises a composition comprising the polyamideimide resin, at least one solid lubricant selected from fluororesin and graphite, and carbon fibers having a fiber diameter of 5 to 15 μm and an average fiber length of 20 to 100 μm. A coating film,
The lubricating coating is characterized in that the thickness of the lubricating coating is 3 to 15 times the fiber diameter of the carbon fiber.   The lubricating coating according to claim 1, wherein the lubricating coating contains 10 to 150 parts by weight of the solid lubricant and 3 to 50 parts by weight of the carbon fiber with respect to 100 parts by weight of the polyamideimide resin.   The lubricating coating according to claim 1 or 2, wherein the lubricating coating has a thickness of 30 to 100 µm.   4. The lubricating coating according to claim 1, wherein the solid lubricant includes at least the fluororesin, and the fluororesin is a polytetrafluoroethylene resin.   The lubricating coating according to claim 4, wherein the solid lubricant includes the graphite, and the graphite is artificial graphite having 97.5% or more of fixed carbon.   The lubricating film according to any one of claims 1 to 5, wherein the lubricating film is formed by dispenser coating and then the surface of the counterpart material is polished.   It is a sliding bearing which has a metal base material and the lubricating film formed in this metal base material surface, Comprising: The said lubricating film is a lubricating film of any one of Claims 1-6. Characteristic sliding bearing.   The sliding bearing according to claim 7, wherein the sliding bearing is a bearing whose sliding surface is lubricated with oil or grease.

Images