Sliding component, compressor, or liquid pump

Abstract

Disclosed is a sliding component comprising: a fixing member; a sliding member disposed facing and spaced apart from the fixing member; and a liquid disposed between the fixing member and the sliding member, wherein the sliding member has a first substrate and a first coating layer directly or indirectly laminated on a surface of the first substrate facing the fixing member, the first coating layer contains engineering plastic and a solid lubricant, and the ratio of the friction coefficient at a bearing characteristic number of 8×10-9 to the friction coefficient at a bearing characteristic number of 8×10-10 on a surface of the sliding member facing the fixing member is 75% or less.

Description

Sliding parts, compressors or liquid pumps

[0001] This application claims priority to Japanese Patent Application No. 2024-106142, filed July 1, 2024, and incorporates by reference all of the contents of that application.

[0002] Wear resistance and heat resistance are required for sliding parts such as oil pumps that pump engine oil to various locations inside an engine. Cross-linked fluororesins have been disclosed as coating agents for rotors, which are the sliding parts of such oil pumps. In the prior art, for example, it has been proposed to coat a substrate with a fluororesin that has been irradiated with ionizing radiation (see Patent Document 1).

[0003] Japanese Patent Application Laid-Open No. 2011-208802

[0004] The sliding component of the present disclosure includes a fixed member, a sliding member disposed opposite the fixed member with a gap therebetween, and a liquid interposed between the fixed member and the sliding member, the sliding member having a first base and a first coating layer laminated directly or indirectly on a surface of the first base facing the fixed member, the first coating layer containing an engineering plastic and a solid lubricant, and a bearing characteristic number of 8×10 on the surface of the sliding member facing the fixed member. －１０ Bearing characteristics for the friction coefficient at 8 x 10 －９ The coefficient of friction at is 75% or less.

[0005] Fig. 1 is a schematic cross-sectional view showing a sliding component according to an embodiment of the present disclosure. Fig. 2 is a schematic configuration diagram showing a compressor according to an embodiment of the present disclosure including the sliding component. Fig. 3 is a schematic cross-sectional view showing a sliding component according to another embodiment of the present disclosure.

[0006] In recent years, with the increasing demand for higher speeds and improved fuel efficiency in sliding parts, there has been a demand for further improvement in the seizure resistance of sliding parts, for example, those provided in rotary and piston-type liquid pumping devices.

[0007] An object of the present disclosure is to provide a sliding component that has excellent seizure resistance.

[0008] The sliding component of the present disclosure has excellent seizure resistance.

[0009] First, embodiments of the present disclosure will be listed and described.

[0010] (1) A sliding component according to the present disclosure includes a fixed member, a sliding member disposed opposite the fixed member with a gap therebetween, and a liquid interposed between the fixed member and the sliding member, the sliding member having a first base and a first coating layer laminated directly or indirectly on a surface of the first base facing the fixed member, the first coating layer containing an engineering plastic and a solid lubricant, and a bearing characteristic number of 8×10 on the surface of the sliding member facing the fixed member. －１０ Bearing characteristics for the friction coefficient at 8 x 10 －９ The coefficient of friction at is 75% or less.

[0011] In the sliding component, the sliding member has a first base and a first coating layer laminated directly or indirectly on the surface of the first base facing the fixed member, and the first coating layer contains an engineering plastic and a solid lubricant, thereby increasing the hardness of the first coating layer of the sliding member disposed opposite the fixed member and improving the sliding properties of the sliding member. －１０ Bearing characteristics for the friction coefficient at 8 x 10 －９ When the ratio of the friction coefficient at 8×10 is 75% or less, the sliding property of the sliding member arranged opposite to the fixed member is improved. Therefore, the sliding part has excellent seizure resistance. In the present disclosure, the above-mentioned "bearing characteristic number" is an index representing the lubrication state of the bearing, and is represented by ηv / p. Here, η is the viscosity of the liquid [mPa·s], v is the sliding speed on the sliding surface [m / min], and p is the average surface pressure [Pa]. "Bearing characteristic number 8×10 －９ "Friction coefficient at" and "Bearing characteristics number 8 x 10 －１０ The "coefficient of friction at" can be measured by a pin-on-disk method ("T-PID / 44, MCR Tribology Cell" manufactured by Anton Paar).

[0012] (2) In the above (1), the number of bearing characteristics on the surface of the sliding member facing the fixed member is 8×10 －１０ Bearing characteristics for the friction coefficient at 8 x 10 －８ The ratio of the friction coefficient at the time of the bearing characteristic number 8×10 may be 30% or less. －１０ Bearing characteristics for the friction coefficient at 8 x 10 －８ When the ratio of the friction coefficient at 8×10 is 30% or less, the sliding property of the sliding member is improved, and therefore the sliding part can have improved seizure resistance. －８ The "coefficient of friction at" can be measured by a pin-on-disk method ("T-PID / 44, MCR Tribology Cell" manufactured by Anton Paar).

[0013] (3) In the above (1) or (2), the fixed member may have a second base and a second coating layer laminated directly or indirectly on the surface of the second base facing the sliding member, the second coating layer containing an engineering plastic and a solid lubricant. In this sliding component, the fixed member has a second base and a second coating layer laminated directly or indirectly on the surface of the second base facing the sliding member, and the second coating layer contains an engineering plastic and a solid lubricant, thereby increasing the hardness of the second coating layer of the fixed member and improving the sliding properties of the fixed member.

[0014] (4) In (3) above, the viscosity of the liquid may be 10,000 mPa·s or less. When the viscosity of the liquid is 10,000 mPa·s or less, the initial coefficient of friction is low. This allows for improved fuel economy in addition to improved seizure resistance. The "viscosity of the liquid" refers to the viscosity of the liquid at the temperature during the friction test using the pin-on-disk method.

[0015] (5) In any of (1) to (4) above, at least one of the surfaces of the first coating layer of the sliding member and the second coating layer of the fixed member may have a pencil hardness of 3H or higher. In this sliding component, the pencil hardness of at least one of the surfaces of the first coating layer of the sliding member and the second coating layer of the fixed member is 3H or higher, thereby further improving the wear resistance of at least one of the surfaces of the sliding member facing the fixed member and the surfaces of the fixed member facing the sliding member. Therefore, the sliding component can have improved seizure resistance. Here, "pencil hardness" refers to a value measured in accordance with JIS-K5600-5-4:1999 "General Test Methods for Coating Materials - Part 5: Mechanical Properties of Coating Films - Section 4: Scratch Hardness (Pencil Method)."

[0016] (6) The compressor or liquid pump of the present disclosure includes the sliding component according to any one of (1) to (5) above. Because the compressor or liquid pump includes the sliding component according to any one of (1) to (5) above, the sliding component has excellent seizure resistance.

[0017] [Details of Embodiments of the Present Disclosure] Hereinafter, sliding components, compressors, or liquid pumps according to embodiments of the present disclosure will be described in detail with reference to the drawings.

[0018] <Sliding Component> A sliding component according to an embodiment of the present disclosure includes a fixed member, a sliding member disposed opposite the fixed member with a gap therebetween, and a liquid interposed between the fixed member and the sliding member. That is, the fixed member serves as a mating member for the sliding member. The sliding member also includes a first substrate and a first coating layer laminated directly or indirectly on a surface of the first substrate facing the fixed member. FIG. 1 is a schematic cross-sectional view showing a sliding component 20 according to an embodiment of the present disclosure. The sliding component 20 includes a fixed member 10, a sliding member 1 disposed opposite the fixed member 10 with a gap therebetween, and a liquid 5 interposed between the fixed member 10 and the sliding member 1.

[0019] [Sliding Member] The sliding member 1 has a first substrate 2 and a first coating layer 3 laminated directly or indirectly on the surface of the first substrate 2 facing the fixing member 10 .

[0020] (First Base) The shape of the first base 2 is not particularly limited and can be changed appropriately depending on the application. For example, it is not limited to a plate-like, cylindrical, conical, elliptical cone-like, pyramidal, gourd-like, elliptical cylinder-like, or rectangular cylinder-like shape, and various shapes of sliding parts such as a rotor can be used.

[0021] The main component of the first substrate 2 is not particularly limited and may be, for example, a metal, super engineering plastic, ceramic, or carbon material. Examples of the metal include iron alloys such as stainless steel, nickel, aluminum, aluminum alloys, copper, and copper alloys. The metals may be used alone or in combination. Examples of the super engineering plastic include polyimide, polyamideimide, polyetherimide, polyetheretherketone, polyphenylene sulfide, polyarylate, liquid crystal polymer, polysulfone, and polyethersulfone. Examples of the ceramic include alumina, aluminum nitride, silicon nitride, boron nitride, silicon carbide, zirconia, cordierite, sialon, steatite, sapphire, and cermet. Examples of the carbon material include diamond, graphite, C / C composites, and C / SiC composites. Among these, the first substrate 2 may be a metal sintered body. Since the surface of a metal sintered body has pores and an uneven shape, the adhesion between the first substrate 2 and the first coating layer 3 can be improved by using a metal sintered body as the first substrate 2. The metal sintered body is formed by compressing a metal powder material in a mold and heating the resulting powder compact at a high temperature below the melting point. The "main component" mentioned above refers to the component with the highest content ratio in terms of mass, for example, a component with a content of 60 mass% or more.

[0022] The average thickness of the first substrate 2 is not particularly limited and can be changed appropriately depending on the application. The first substrate 2 may have through holes.

[0023] (First Coating Layer) In this embodiment, the first coating layer 3 is laminated directly on the surface of the first substrate 2. The first coating layer 3 may be a coating layer. When the first coating layer 3 is a coating layer, it becomes easy to control the surface roughness of the first coating layer 3 and the accuracy of the average thickness of the first coating layer 3.

[0024] The first coating layer 3 contains an engineering plastic and a solid lubricant. The inclusion of the engineering plastic in the first coating layer 3 increases the hardness of the first coating layer 3. This improves the abrasion resistance of the first coating layer 3 during sliding, allowing it to be used as a sliding member that can withstand long-term use. Furthermore, the inclusion of the solid lubricant in the first coating layer 3 improves the wear resistance of the sliding member 1.

[0025] The first coating layer 3 does not need to be laminated over the entire surface of the first substrate 2, but only needs to be laminated over at least the surface of the first substrate 2 facing the fixing member 10. For example, when the first substrate 2 is plate-shaped as shown in FIG. 1 , the first coating layer 3 may be laminated directly over only the first surface of the first substrate 2, or may be laminated directly over both the first and second surfaces of the first substrate 2. Furthermore, when the first substrate 2 is cylindrical, the first coating layer 3 may be laminated directly over the entire surface of the first substrate 2, or may be laminated directly over only the surface of the first substrate 2 facing the fixing member 10. Furthermore, the surface of the first coating layer 3 does not need to be flat, and a pattern such as grooves or dimples (depressions) may be formed on the surface.

[0026] The lower limit of the average thickness of the first coating layer 3 may be 3.0 μm or 4.0 μm. On the other hand, the upper limit of the average thickness may be 60.0 μm, 50.0 μm, or 40.0 μm. When the average thickness is 3.0 μm or more, the abrasion resistance when foreign matter is caught can be improved. On the other hand, when the average thickness is 60.0 μm or less, the elasticity of the sliding member 1 is less likely to decrease. The "average thickness" refers to the average value of thicknesses measured at any ten points.

[0027] The flatness of the surface of the first coating layer 3 may be 0.005 or less, and the parallelism may be 0.005 or less. When the flatness of the surface of the first coating layer 3 is 0.005 or less and the parallelism is 0.005 or less, the sliding properties of the first coating layer 3 are further improved, and as a result, the wear resistance of the sliding member 1 can be further increased. The units of flatness and parallelism are mm. The flatness and parallelism of the surface of the first coating layer 3 can be adjusted by polishing the coating film of the first coating layer 3, as described below. Here, "flatness" is a value measured in accordance with JIS-B0684-1:2019. Furthermore, "parallelism" is a value measured in accordance with JIS-B0621:1984.

[0028] (Engineering plastics) Examples of engineering plastics include polyimide, polycarbonate, polyamideimide, polybenzimidazole, polyphenylsulfone, polyethersulfone, and polyetheretherketone. Among these, polyimide or polyamideimide may be used from the viewpoint of further improving surface properties and abrasion resistance. These engineering plastics may be used alone or in combination.

[0029] <Polyimide> The polyimide is a polymer having an imide bond (-CONCO-) in the main chain. Polyimide has excellent heat resistance and high toughness. Polyimide is a polymer of an aromatic tetracarboxylic dianhydride and an aromatic diamine. In other words, polyimide is a polymer having a structure in which structural units derived from an aromatic tetracarboxylic dianhydride and structural units derived from an aromatic diamine are repeatedly bonded. Here, "acid dianhydride" refers to a compound having a structure in which two water molecules are eliminated from four carboxylic acid groups contained in the molecule (a structure in which one molecule contains two carboxylic acid group pairs each consisting of two adjacent carboxylic acid groups, and one water molecule is eliminated from each carboxylic acid group pair).

[0030] The polyimide is formed by curing the polyimide precursor by heating the resin composition for the coating layer used to form the first coating layer 3. That is, the polyimide precursor undergoes a dehydration cycloreaction (imidization reaction) to form a cyclic imide, thereby becoming a polyimide. The polyimide precursor is a reaction product obtained by a polycondensation reaction between an aromatic tetracarboxylic dianhydride and an aromatic diamine. The polyimide precursor is a compound also known as a polyamic acid (polyamic acid).

[0031] When the aromatic tetracarboxylic dianhydride contains pyromellitic dianhydride (PMDA), the heat resistance of the first coating layer 3 can be improved. This is because PMDA has a rigid and linear molecular structure. The aromatic tetracarboxylic dianhydride may contain an aromatic tetracarboxylic dianhydride other than PMDA (hereinafter, also referred to as "another aromatic tetracarboxylic dianhydride").

[0032] Examples of the other aromatic tetracarboxylic dianhydrides include 3,3',4,4'-biphenyltetracarboxylic dianhydride (s-BPDA), 2,3,3',4'-biphenyltetracarboxylic dianhydride (a-BPDA), 2,2',3,3'-biphenyltetracarboxylic dianhydride (i-BPDA), 3,3',4,4'-benzophenonetetracarboxylic dianhydride, 4,4'-oxydiphthalic dianhydride, 2,2',3,3'-benzophenonetetracarboxylic dianhydride, 2,2-bis(3,4-dicarboxyphenyl)propane dianhydride, 2,2-bis(3,4-dicarboxyphenyl)propane dianhydride, and 2,2-bis(3,4-dicarboxyphenyl)propane dianhydride. Examples of the other aromatic tetracarboxylic dianhydrides include bis(2,3-dicarboxyphenyl)propane dianhydride, 1,1-bis(3,4-dicarboxyphenyl)ethane dianhydride, 1,1-bis(2,3-dicarboxyphenyl)ethane dianhydride, bis(3,4-dicarboxyphenyl)methane dianhydride, bis(2,3-dicarboxyphenyl)methane dianhydride, bis(3,4-dicarboxyphenyl)sulfone dianhydride, bis(3,4-dicarboxyphenyl)ether dianhydride, 1,2,5,6-naphthalenetetracarboxylic dianhydride, and 2,3,6,7-naphthalenetetracarboxylic dianhydride. These other aromatic tetracarboxylic dianhydrides may be used alone or in combination of two or more.

[0033] When the other aromatic tetracarboxylic dianhydride is biphenyltetracarboxylic dianhydride (BPDA), the hydrolysis resistance of the polyimide precursor can be improved.

[0034] The lower limit of the amount of PMDA relative to 100 mol% of the aromatic tetracarboxylic dianhydride may be 10 mol%, 20 mol%, or 30 mol%, and the upper limit of the amount of PMDA relative to 100 mol% of the aromatic tetracarboxylic dianhydride may be 100 mol%, 90 mol%, 80 mol%, or 70 mol%.

[0035] The content of the other aromatic tetracarboxylic dianhydride relative to 100 mol% of the aromatic tetracarboxylic dianhydride can be appropriately determined within a range that does not impair the effects of the present disclosure. The upper limit of the content may be 30 mol% or 20 mol%. The lower limit of the content may be 0 mol% or 10 mol%.

[0036] When the aromatic diamine contains diaminodiphenyl ether (ODA), the heat resistance of the first coating layer 3 can be improved. This is because ODA has a rigid and linear molecular structure. Examples of diaminodiphenyl ethers include 4,4'-diaminodiphenyl ether (4,4'-ODA), 3,4'-diaminodiphenyl ether (3,4'-ODA), 3,3'-diaminodiphenyl ether (3,3'-ODA), 2,4'-diaminodiphenyl ether (2,4'-ODA), and 2,2'-diaminodiphenyl ether (2,2'-ODA). 4,4'-diaminodiphenyl ether (4,4'-ODA) can improve the film elongation of the first coating layer 3.

[0037] The lower limit of the ODA content relative to 100 mol% of the aromatic diamine may be 50 mol%, 60 mol%, or 70 mol%, and the upper limit of the ODA content relative to 100 mol% of the aromatic diamine may be 100 mol% or 90 mol%.

[0038] The aromatic diamine may further contain an aromatic diamine other than ODA (hereinafter also referred to as "other aromatic diamine"). Examples of the other aromatic diamine include 2,2-bis[4-(4-aminophenoxy)phenyl]propane (BAPP), 4,4'-bis(4-aminophenoxy)biphenyl (BAPB), 4,4'-diaminodiphenylmethane, 3,4'-diaminodiphenylmethane, 3,3'-diaminodiphenylmethane, 2,4'-diaminodiphenylmethane, 2,2'-diaminodiphenylmethane, 4,4'-diaminodiphenylsulfone, 3,4'-diaminodiphenylsulfone, 3,3'-diaminodiphenylsulfone, 2,4'-diaminodiphenylsulfone, 2,2'-diaminodiphenylsulfone, 4,4' Examples of the other aromatic diamines include 4,4'-diaminodiphenyl sulfide, 3,4'-diaminodiphenyl sulfide, 3,3'-diaminodiphenyl sulfide, 2,4'-diaminodiphenyl sulfide, 2,2'-diaminodiphenyl sulfide, paraphenylenediamine, metaphenylenediamine, p-xylylenediamine, m-xylylenediamine, 2,2'-dimethyl-4,4'-diaminobiphenyl (mTBHG), 1,5-diaminonaphthalene, 4,4'-benzophenonediamine, 3,3'-dimethyl-4,4'-diaminodiphenylmethane, and 3,3',5,5'-tetramethyl-4,4'-diaminodiphenylmethane. The other aromatic diamines may be used alone or in combination of two or more.

[0039] If the other aromatic diamine is 2,2-bis[4-(4-aminophenoxy)phenyl]propane (BAPP) or 4,4′-bis(4-aminophenoxy)biphenyl (BAPB), the relative dielectric constant of the first coating layer 3 can be reduced.

[0040] The content of the other aromatic diamine relative to 100 mol% of the aromatic diamine can be appropriately determined within a range that does not impair the effects of the present disclosure. The upper limit of the content may be 40 mol% or 30 mol%. The lower limit of the content may be 0 mol% or 10 mol%.

[0041] The molar ratio of the aromatic tetracarboxylic dianhydride to the aromatic diamine used as raw materials for the polyimide precursor (aromatic tetracarboxylic dianhydride:aromatic diamine) may be, for example, 95:105 or more and 105:95 or less, 97:103 or more and 103:97 or less, or 99:101 or more and 101:99 or less, from the viewpoint of ease of synthesis of the polyimide precursor. The aromatic tetracarboxylic dianhydride and the aromatic diamine may be substantially equimolar amounts. In this case, the molecular weight of the polyimide precursor can be easily increased. The term "substantially equimolar amount" refers to a molar ratio of the aromatic tetracarboxylic dianhydride to the aromatic diamine (aromatic tetracarboxylic dianhydride:aromatic diamine) in the range of 99:101 or more and 101:99 or less.

[0042] The first coating layer 3 may contain a resin other than engineering plastics, such as thermosetting resins such as polyvinyl formal, polyurethane, alkyl resin, epoxy resin, phenoxy resin, polyester, polyesterimide, and polyesteramideimide, and thermoplastic resins such as polyetherimide.

[0043] The lower limit of the polyimide content in the first coating layer 3 may be 55 mass%, 60 mass%, or 70 mass%. When the polyimide content is 55 mass% or more, the first coating layer 3 can obtain sufficient hardness. On the other hand, the upper limit of the polyimide content in the first coating layer 3 may be 95 mass%, 90 mass%, or 85 mass%. When the polyimide content is 95 mass% or less, the proportion of solid lubricant can be maintained and good wear resistance can be obtained.

[0044] (Solid Lubricant) The first coating layer 3 contains a solid lubricant. When the first coating layer 3 contains a solid lubricant, the wear resistance of the sliding member 1 is improved. Examples of solid lubricants include polytetrafluoroethylene (PTFE), tetrafluoroethylene-perfluoroalkoxyethylene copolymer (PFA), molybdenum disulfide, graphite, tetrafluoroethylene-hexafluoropropylene copolymer (FEP), ultra-high molecular weight polyethylene, and combinations thereof. Among these, polytetrafluoroethylene and tetrafluoroethylene-perfluoroalkoxyethylene copolymer may be used from the viewpoint of exhibiting better wear resistance.

[0045] The lower limit of the volume ratio of the solid lubricant to the engineering plastic may be 5% or 10%. When the volume ratio of the solid lubricant is 5% or more, the surface quality and wear resistance of the first coating layer 3 can be improved. On the other hand, the upper limit of the volume ratio of the solid lubricant may be 30%, 25%, or 20%. When the volume ratio of the solid lubricant is 30% or less, the hardness of the first coating layer 3 can be improved and the wear resistance can be improved.

[0046] The lower limit of the average particle size of the solid lubricant may be 0.1 μm or 0.2 μm. When the average particle size of the solid lubricant is 0.1 μm or more, the first coating layer 3 is less likely to soften, and deterioration of wear resistance and inclusion of foreign matter can be further reduced. On the other hand, the upper limit of the average particle size of the solid lubricant may be 10.0 μm or 9.0 μm. When the average particle size of the solid lubricant is 10.0 μm or less, the surface roughness of the first coating layer 3 is further reduced, and the wear amount and torque of the first coating layer 3 are less likely to increase. The "average particle size" refers to the median diameter (D50), which is the value at which the volume-based cumulative distribution calculated in accordance with JIS-Z-8819-2:2001 is 50%. Specifically, the median diameter (D50) can be measured using the following method. Measurement is performed using a laser diffraction particle size distribution analyzer. A scattering measurement mode is adopted, and a laser beam is irradiated onto a wet cell in which the particles of the sample to be measured are dispersed in a dispersion solvent, and a scattered light distribution is obtained from the measurement sample.The scattered light distribution is then approximated by a log-normal distribution, and the particle diameter at a cumulative degree of 50% (D50) is taken as the median diameter.In addition, even if the shape of the solid lubricant is scaly, the particle shape is assumed to be spherical, and measurement is similarly performed using a laser diffraction particle size distribution analyzer.

[0047] (Silicon Compound) The first coating layer 3 may further contain a silicon compound. By containing a silicon compound as an additive in the first coating layer 3, the surface properties of the first coating layer 3 are improved, and the slipperiness of the first coating layer 3 is improved, thereby making it possible to further increase the wear resistance.

[0048] The silicon compound may be modified polydimethylsiloxane. Modified polydimethylsiloxane has a structure in which a substituent has been introduced into a portion of a silicone having a siloxane bond as its main skeleton. When the first coating layer 3 contains modified polydimethylsiloxane as an additive, the surface tension of the resin composition for the coating layer forming the first coating layer 3 is significantly reduced, effectively acting as a leveling agent during application and improving film thickness accuracy. This improves the surface properties of the first coating layer 3, further improving the slipperiness of the first coating layer 3 and thereby increasing abrasion resistance. Furthermore, thixotropy suitable for application of the resin composition for the coating layer can be imparted.

[0049] The modified polydimethylsiloxane may be either a linear modified polydimethylsiloxane or a cyclic modified polydimethylsiloxane. A mixture of a linear modified polydimethylsiloxane and a cyclic modified polydimethylsiloxane may also be used. A mixture of modified polydimethylsiloxanes with different molecular weights may also be used. Examples of modified polydimethylsiloxanes include modified polydimethylsiloxanes having a structure substituted with hydroxyl groups, amino groups, (poly)ether groups, epoxy groups, carboxy groups, carbinol groups, mercapto groups, phenol groups, ester groups, alkoxy groups, halogen atoms, aralkyl groups, aralkyl groups, long-chain alkyl groups, higher fatty acid ester groups, higher aliphatic amide groups, etc. Specific examples of modified polydimethylsiloxanes include polyether-modified polydimethylsiloxanes, polyester-modified polydimethylsiloxanes, hydroxyl-containing polyester-modified polydimethylsiloxanes, polyarakyl-modified polydimethylsiloxanes, and epoxy-functional polyether-modified polydimethylsiloxanes. Among these, the modified polydimethylsiloxane may be a polyether-modified polydimethylsiloxane having a polyether-modifying group, from the viewpoint of the effect of reducing surface tension.

[0050] When the first coating layer 3 further contains a silicon compound, the lower limit of the content of the silicon compound in the first coating layer 3 may be 0.01% by mass, 0.02% by mass, or 0.03% by mass. When the content of the silicon compound is 0.01% by mass or more, the surface quality and abrasion resistance of the first coating layer 3 can be improved. On the other hand, the upper limit of the content of the silicon compound may be 10.00% by mass, 9.00% by mass, or 8.00% by mass. When the content of the silicon compound is less than 10.00% by mass, the hardness and surface quality of the first coating layer 3 can be improved.

[0051] The first coating layer 3 may further contain additives other than the silicon compound, as needed, such as anti-settling agents, dispersants, anti-foaming agents, coloring pigments, antioxidants, ultraviolet absorbers, antistatic agents, and surfactants.

[0052] The lower limit of the pencil hardness of the surface of the first coating layer 3 may be 3H or 4H. In the sliding component 20, when the pencil hardness of the surface of the first coating layer 3 is 3H or more, the surface properties of the first coating layer 3 can be further improved, the wear resistance of the surface of the sliding member 1 facing the fixed member 10 can be further increased, and seizure resistance can be improved. In addition, in the sliding member 1, when the pencil hardness of the surface of the first coating layer 3 is 3H or more, the first coating layer 3 has sufficient hardness, and therefore the likelihood of foreign matter getting caught in the sliding member 1 can be further reduced. The upper limit of the pencil hardness of the surface of the first coating layer 3 is not particularly limited, but may be, for example, 7H.

[0053] [Fixed Member] The fixed member 10 has a second substrate 12. For the second substrate 12, the same material as that for the first substrate 2 of the slide member 1 described above can be used.

[0054] [Liquid] The liquid 5 may be, for example, oil as a lubricant or water as a refrigerant. Examples of the oil include mineral oil, alkylbenzene oil, ether oil, ester oil, and polyalkyl glycol.

[0055] The upper limit of the viscosity of the liquid 5 may be 10,000 mPa·s or 9,000 mPa·s. When the viscosity of the liquid 5 is 10,000 mPa·s or less, the lubricity between the fixed member 10 and the sliding member 1 can be improved, thereby further improving the seizure resistance of the sliding component 20. The lower limit of the viscosity of the liquid 5 is not particularly limited, but may be, for example, 0.1 mPa·s.

[0056] The number of bearing characteristics on the surface of the sliding member 1 facing the fixed member 10 is 8×10 －１０ Bearing characteristics for the friction coefficient at 8 x 10 －９ The upper limit of the ratio of the friction coefficient at the sliding member 1 is 75%, and it may be 70%. －１０ Bearing characteristics for the friction coefficient at 8 x 10 －９ When the ratio of the friction coefficient at the sliding element 1 is 75% or less, the sliding property of the sliding element 1 is improved. Therefore, the sliding element 20 has excellent seizure resistance. Furthermore, since the friction coefficient is an index of power consumption, fuel efficiency can be further improved. －１０ The lower limit of the ratio of the friction coefficient at the bearing characteristic number 1.08×10 −7 to the friction coefficient at the bearing characteristic number 1.08×10 −7 is not particularly limited, but may be, for example, 50%.

[0057] The number of bearing characteristics on the surface of the sliding member 1 facing the fixed member 10 is 8×10 －１０ Bearing characteristics for the friction coefficient at 8 x 10 －８ The upper limit of the ratio of the friction coefficient at the sliding member 1 is 30%, and it may be 28%. －１０ Bearing characteristics for the friction coefficient at 8 x 10 －８ When the ratio of the friction coefficient at 8×10 is 30% or less, the sliding property of the sliding member 1 is improved. Therefore, the sliding component 20 can have improved seizure resistance. －１０ Bearing characteristics for the friction coefficient at 8 x 10 －８ The lower limit of the ratio of the coefficient of friction is not particularly limited, but may be, for example, 15%.

[0058] [Method for Manufacturing Sliding Component] A method for manufacturing the sliding component according to one embodiment includes the steps of: laminating a first coating layer containing, for example, an engineering plastic and a solid lubricant directly or indirectly on at least a part of the surface of a first base used in the sliding component; arranging a fixing member and a sliding component; and providing a liquid between the fixing member and the sliding component.

[0059] (Laminating Step) In this step, a first coating layer containing an engineering plastic and a solid lubricant is laminated directly or indirectly onto at least a portion of the surface of the first substrate.

[0060] Examples of the lamination method include a method of applying a coating material for forming the first coating layer to the surface of the first substrate, using, for example, precision coating by air spray, a roll coater, a bar coater, an inkjet printer, a dispenser, dip coating, or screen printing.

[0061] Examples of the coating material include a coating material in which a resin composition for the first coating layer containing a polyimide precursor and a solid lubricant is dispersed in a solvent, or a coating material in which the resin composition is dissolved in a solvent. Examples of the solvent include amide-based solvents such as N-methylpyrrolidone, 2-pyrrolidone, dimethylacetamide, N,N-dimethylformamide, and N,N-diethylformamide, as well as mixtures of the amide-based solvents with other solvents such as water, alcohols, ketones, ethers, esters, amines, and combinations thereof. The coating material can be prepared by mechanically stirring and mixing a resin composition for the coating layer, which is prepared by blending predetermined amounts of the polyimide precursor and the solid lubricant, in the solvent.

[0062] The lower limit of the solids concentration of the coating material may be 2 mass%, 25 mass%, or 40 mass%, while the upper limit of the solids concentration of the coating material may be 60 mass%, 50 mass%, or 45 mass%. By setting the solids concentration of the coating material within the above range, coatability can be improved, and as a result, a coating film with few coating defects can be easily and reliably formed.

[0063] After coating the surface of the first substrate with paint, the first substrate is placed in a heating furnace and heated to bake the resin composition for the coating layer formed in a layer. The baking process allows the solvent in the paint to be removed and the first coating layer to be formed. The heating temperature when baking the coating film of the resin composition for the coating layer can be, for example, 350°C or higher and 400°C or lower. The heating time when baking the coating film can be, for example, 5 minutes or higher and 60 minutes or lower. By setting the heating temperature and heating time within the above ranges, a film with excellent density can be formed while suppressing resin decomposition. After cooling the first substrate, the surface of the coating film may be polished. By polishing the surface of the coating film, the surface properties of the first coating layer can be improved. In this way, the first coating layer is laminated on the surface of the first substrate.

[0064] In order to improve the adhesion between the first substrate and the coating film, the surface of the first substrate may be subjected to a surface treatment or roughening treatment such as sandblasting, shot peening, etching, zinc phosphate treatment, zinc calcium phosphate treatment, manganese phosphate treatment, nickel plating, zinc plating, other plating treatments, or roughening treatment by sanding.

[0065] As described above, the first coating layer does not need to be laminated on the entire surface of the first substrate, but only needs to be laminated on at least the surface of the first substrate that faces the fixing member.

[0066] (Step of Arranging the Fixed Member and the Sliding Member) In this step, the second base used as the fixed member and the sliding member obtained after the lamination step are arranged. Specifically, in this step, the sliding member is arranged opposite the second base used as the fixed member with a gap therebetween.

[0067] (Step of providing a liquid) In this step, a liquid is provided between the fixed member and the sliding member. The amount of liquid provided between the fixed member and the sliding member can be adjusted as appropriate. Details of each element of the sliding component obtained by the above-mentioned method for manufacturing a sliding component are as described above.

[0068] The sliding component has excellent seizure resistance and can therefore be suitably used as a sliding component for a swing compressor, a rotary compressor, a piston compressor that moves up and down, a rotor for an oil pump, or other rotary devices and components, a reciprocating mold, or the like.

[0069] <Compressor> When pressure equipment such as a compressor or a liquid pump is provided with the sliding component, the sliding component has excellent seizure resistance. Fig. 2 is a schematic diagram showing the configuration of a compressor according to one embodiment that is provided with the sliding component.

[0070] The rotary compressor 50 comprises a cylinder 48, which is a fixed member; a roller 42, which is disposed opposite the cylinder 48 with a gap therebetween and moves eccentrically within the cylinder 48; a vane 40, which abuts against the roller 42 and divides the interior of the cylinder 48 into a low-pressure chamber and a high-pressure chamber; and a first coating layer 44, which is laminated on the surface of the roller 42. In the compressor 50, the roller 42 and the first coating layer 44 are sliding members. The first coating layer 44 contains an engineering plastic and a solid lubricant. The bearing characteristic number of the roller 42 and the first coating layer 44, which are sliding members, on the surface facing the cylinder 48, is 8×10. －１０ Bearing characteristics for the friction coefficient at 8 x 10 －９ The coefficient of friction at is 75% or less.

[0071] A groove is formed in the cylinder 48, and the vane 40 is disposed in the groove. The vane 40 can reciprocate due to a spring (not shown). The roller 42 is engaged with an eccentric part 43 having a rotation shaft (not shown) that rotates eccentrically electrically. By engaging the roller 42 with the eccentric part 43, the roller 42 slides and moves eccentrically while in contact with the inner surface of the cylinder 48.

[0072] Oil (not shown) is poured into a space 46 provided between the cylinder 48, which is a fixed member, and the roller 42 and first coating layer 44, which are sliding members arranged opposite the cylinder 48. The presence of oil between the cylinder 48, which is a fixed member, and the roller 42 and first coating layer 44, which are sliding members, improves the lubricity between the cylinder 48, which is a fixed member, and the roller 42 and first coating layer 44, which are sliding members. Furthermore, in the compressor 50, by providing the roller 42, which has the first coating layer 44 laminated on its surface as a sliding member, the sliding properties of the sliding member are improved. In addition, the bearing characteristic number 8×10 on the surface of the roller 42 and first coating layer 44 facing the cylinder 48 is －１０ Bearing characteristics for the friction coefficient at 8 x 10 －９ When the ratio of the coefficient of friction at 1000 to 15000 is 75% or less, the sliding properties of the roller 42 and the first coating layer 44 that are arranged opposite the cylinder 48 can be further improved. Therefore, the compressor 50 has excellent seizure resistance.

[0073] [Other Embodiments] The embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive. The scope of the present invention is not limited to the configurations of the above-described embodiments, but is defined by the claims, and is intended to include all modifications within the meaning and scope of the claims.

[0074] In the above embodiment, the fixing member is formed from a second base. However, in the sliding component, the fixing member may include a second base and a second coating layer laminated directly or indirectly on the surface of the second base facing the slide member. FIG. 3 is a schematic cross-sectional view showing a sliding component according to another embodiment. As shown in FIG. 3 , the sliding component 30 includes a fixing member 15, a slide member 1 disposed facing the fixing member 15 at a distance, and a liquid 5 interposed between the fixing member 15 and the slide member 1. The fixing member 15 includes a second base 12 and a second coating layer 11 laminated directly or indirectly on the surface of the second base 12 facing the slide member 1. The second base 12 and the second coating layer 11 may have the same configuration as the first base and the first coating layer described above.

[0075] Like the first coating layer 3 of the sliding member 1 described above, the second coating layer 11 contains an engineering plastic, which increases the hardness of the second coating layer 11. This improves the abrasion resistance of the second coating layer 11 during sliding, and as a result, the second coating layer 11 can be used as a fixing member 15 that can withstand long-term use. Furthermore, the second coating layer 11 contains a solid lubricant, which improves the wear resistance of the fixing member 15.

[0076] The lower limit of the pencil hardness of the surface of the second coating layer 11 may be 3H or 4H, as with the first coating layer 3. In the sliding component 30, when the pencil hardness of the surface of the second coating layer 11 is 3H or higher, the surface properties of the second coating layer 11 can be further improved, the wear resistance of the surface of the fixed member 15 facing the sliding member 1 can be further increased, and the seizure resistance can be further increased. Note that in the sliding component 30, the pencil hardness of only the surface of the second coating layer of the fixed member may be 3H or higher. The upper limit of the pencil hardness of the surface of the second coating layer 11 is not particularly limited, but may be, for example, 7H.

[0077] In the plate-like first base 2 in the sliding member 1 of the sliding part 20 and the sliding part 30 and the plate-like second base 12 in the fixing member 15 of the sliding part 30, the first coating layer 3 or the second coating layer 11 is laminated only on the first surface (one surface). However, the first coating layer or the second coating layer may be laminated directly or indirectly on the first surface and the second surface (both surfaces) of the plate-like first base 2 and the plate-like second base 12.

[0078] In the above embodiment, the first coating layer 3 is laminated directly on the surface of the first substrate 2, but an intermediate layer may be further provided between the first substrate 2 and the first coating layer 3. Providing the sliding component with an intermediate layer can further increase the hardness of the first coating layer 3. An example of the intermediate layer is a resin layer containing the above-mentioned engineering plastic as a main component.

[0079] The present disclosure will be described in more detail below with reference to examples, but the present disclosure is not limited to the following examples.

[0080] <Sliding Parts No. 1, No. 2, No. 4 to No. 12> A coating layer containing an engineering plastic, solid lubricant, and additives in the amounts shown in Table 1 was directly laminated onto the end face of a stainless steel pin with a diameter of 6 mm and an average thickness of 8 mm as a sliding member, using the following procedure. First, the solid lubricant shown in Table 1 was added to the engineering plastic in an amount of 10.00 volume % relative to the engineering plastic, except for No. 2. For No. 2, the solid lubricant was added in an amount of 20.00 volume % relative to the engineering plastic. Furthermore, modified polydimethylsiloxane was added as a silicone-based leveling additive, adjusted to the content [mass %] in the first coating layer shown in Tables 1 and 2. For Nos. 2 and 5, the surfactant "Ftergent 710FL" manufactured by Neos Corporation was added in a mass ratio of 0.12 relative to the solid lubricant. Next, a magnetic stirrer was used to stir the mixture at 1200 rpm for 3 hours to prepare a resin composition for the first coating layer. The resin composition for the first coating layer was then dissolved in a solvent to prepare a paint for the first coating layer. Next, for evaluation of the friction coefficient, the curved surface of a stainless steel pin with a diameter of 6 mm and an average thickness of 8 mm was masked with tape. The paint was bar-coated onto the pin to an average thickness of approximately 20 μm, dried at 100°C for 10 minutes, and then baked at 380°C for 15 minutes to laminate the first coating layer and prepare a test piece for the sliding member. The average thickness [μm] is the dry film thickness. A "-" in the table indicates that the corresponding raw material was not blended.

[0081] A stainless steel (SUS) plate with an average thickness of 5 mm was prepared as the second substrate of the fixing member. The friction coefficient was measured by attaching a tribology cell PID / 44 to an Anton Paar MCR302 rheometer and installing the pin with the first coating layer in the tribology cell. 10 mL of the lubricating oil described below was added as a liquid to the tribology cell tank, and sliding parts No. 1, No. 2, No. 4 to No. 12 were prepared.

[0082] <Sliding Component No. 3> Sliding component No. 3 was prepared as a comparative example in the same manner as Sliding Component No. 1, except that the first coating layer was not laminated on the pin.

[0083] <Sliding Component Nos. 13 to 18> A resin composition for a first coating layer having the composition shown in Table 2 was prepared using the same procedure as for sliding component No. 1, and a paint for a first coating layer was prepared. Pins with a first coating layer laminated thereon were prepared as sliding components for sliding component Nos. 13 to 18. Next, a resin composition for a second coating layer having the composition shown in Table 2 was prepared using the same procedure as for the paint for the first coating layer, and a paint for the second coating layer was prepared. The paint for the second coating layer was then applied to the surface of the second substrate of the fixing member, and a second coating layer was laminated. Sliding components Nos. 13 to 18 were then prepared using the same procedure as for sliding component No. 1.

[0084] The materials used are as follows: (Engineering plastics) (1) Polyimide "UPIA-AT-1001" manufactured by UBE, glass transition temperature 274 to 278°C (2) Polyamideimide "Vylomax HR-11NN" manufactured by Toyobo Co., Ltd. (3) Polycarbonate "Iupizeta FPC-0330" manufactured by Mitsubishi Chemical Corporation (Additives) (1) Polytetrafluoroethylene "TF9207Z" manufactured by 3M Japan Ltd. (2) Molybdenum disulfide "T Powder" manufactured by Daizo Co., Ltd. (3) Tetrafluoroethylene-perfluoroalkoxyethylene copolymer (PFA) "EA-2000 PW10" manufactured by AGC Co., Ltd. (4) Modified polydimethylsiloxane "BYK3760" manufactured by BYK Corporation (Liquids) (1) Low viscosity liquid (viscosity 16 mPa·s at 80°C) "SUNICE" manufactured by Japan Sun Oil Co., Ltd. HYBRID 46" (2) High viscosity liquid (viscosity 9,800 mPa·s at 60°C, viscosity 12,000 mPa·s at 0°C) Shin-Etsu Chemical Co., Ltd. silicone oil "KF96-10,000 CS"

[0085]

[0086]

[0087] <Evaluation> Next, the pencil hardness, friction coefficient, and seizure resistance of sliding components No. 1 to No. 18 were evaluated.

[0088] [Pencil Hardness] After sharpening the pencil tip into a conical shape using an electric sharpener, the pencil was polished vertically on waterproof abrasive paper #2000 manufactured by Nihon Kenshi Co., Ltd., so that the flat portion was within the range of φ0.9 to φ1.1. The polished pencil was pressed firmly against the test piece at an angle of approximately 45° and moved at a speed of approximately 100 mm / sec to evaluate whether the first coating layer was gouged and the first substrate was exposed. Specifically, evaluations were performed in order from 6B, and if the first coating layer was not gouged or the pencil lead broke after three evaluations, the pencil grit was considered to be acceptable. The evaluation was performed by increasing the grit of the pencil until the first coating layer was gouged and the first substrate was exposed. Mitsubishi Pencil uni 6B to 9H pencils were used. The pencil hardness of sliding parts No. 1 to No. 18 is shown in Tables 1 and 2.

[0089] [Friction Test] For sliding parts No. 1 to No. 18, the following procedure was used to measure the bearing characteristics of the sliding member on the surface facing the fixed member: (1) Number of bearing characteristics: 8 × 10 －１０ Friction coefficient at (2) bearing characteristics number 8 x 10 －９ Friction coefficient at, and (3) bearing characteristics number 8 × 10 －８ The friction coefficient was measured at 100°C. Specifically, a tribology cell PID / 44 was attached to a rheometer MCR302 manufactured by Anton Paar, a pin laminated with a first coating layer was attached as a sliding member, and 10 mL of "SUNICE HYBRID 46" manufactured by Nippon Sun Oil Co., Ltd. was dropped into the tank as a lubricant. The normal force FN, which is the load, was set to 10 N, and the bearing characteristic number was 8 × 10. －１０ From 8 x 10 －８ The friction coefficient of the surface of the sliding member facing the fixed member was measured in the range of 8×10. －１０ Bearing characteristics for the friction coefficient at 8 x 10 －９ The ratio of the friction coefficient at the －１０ Bearing characteristics for the friction coefficient at 8 x 10 －８The ratio of the coefficient of friction at each temperature was calculated. The temperature of the liquid with a viscosity of 16 mPa s during measurement was 80°C. For Nos. 10 and 14, which have a liquid viscosity of 9,800 mPa s, measurements were taken using silicone oil KF96-10,000cs manufactured by Shin-Etsu Chemical Co., Ltd. at 60°C, and for Nos. 11 and 15, which have a liquid viscosity of 12,000 mPa s, measurements were taken using silicone oil KF96-10,000cs manufactured by Shin-Etsu Chemical Co., Ltd. at 10°C.

[0090] [Seizure Resistance] The seizure resistance of sliding parts No. 1 to No. 18 was evaluated by the following procedure. The rheometer was set to FN 10N, the temperature was set to 80°C, and the number of bearing characteristics was 8 × 10 －１０ From 8 x 10 －８ A total of 81 seconds of measurement in a logarithmic ramp speed increase mode was counted as one set, and this was repeated three times. The number of sets until the measurement was stopped due to seizure was evaluated. One count was only performed when one set of 81 seconds was completed, and if the measurement stopped midway, it was stopped without being counted. The evaluation criteria were rated on a three-point scale, from A to C. A was assigned to cases where no seizure occurred after three or more repetitions, B was assigned to cases where no seizure occurred after one or two repetitions, and C was assigned to cases where no seizure occurred less than once. A and B were considered to be acceptable. For sliding part No. 3, the first bearing characteristic number, 8 x 10, which is in the high-speed range, was used. －８ At this point, image sticking occurred, so the measurement was stopped and the result was recorded as C.

[0091] The results of evaluation of the friction coefficient μ and seizure resistance of the sliding parts are shown in Tables 3 and 4.

[0092]

[0093]

[0094] As shown in Tables 3 and 4, the sliding member has a first substrate and a first coating layer laminated directly or indirectly on the surface of the first substrate facing the fixed member, the first coating layer containing an engineering plastic and a solid lubricant, and the bearing characteristic number of the surface of the sliding member facing the fixed member is 8×10 －１０ Bearing characteristics for the friction coefficient at 8 x 10 －９The sliding parts No. 1, No. 2 and No. 4 to No. 18, in which the ratio of the friction coefficient at 1000 kJ / cm2 was 75% or less, exhibited good results in terms of seizure resistance.

[0095] On the other hand, the first substrate does not have the first coating layer laminated on the surface facing the fixed member, and the bearing characteristic number of the surface of the sliding member facing the fixed member is 8×10 －１０ Bearing characteristics for the friction coefficient at 8 x 10 －９ The sliding part No. 3, in which the ratio of the friction coefficient at 85% was greater than 75%, was poor in seizure resistance.

[0096] From the above, it was shown that the sliding component has excellent seizure resistance.

[0097] REFERENCE SIGNS LIST 1 Sliding member 2 First base 3, 44 First coating layer 5 Liquid 10, 15 Fixed member 11 Second coating layer 12 Second base 20, 30 Sliding part 40 Vane 42 Roller 43 Eccentric part 46 Space 48 Cylinder 50 Compressor

Claims

1. A method for manufacturing a sliding member comprising: a fixed member; a sliding member disposed opposite the fixed member with a gap therebetween; and a liquid interposed between the fixed member and the sliding member; wherein the sliding member has a first base and a first coating layer laminated directly or indirectly on the surface of the first base facing the fixed member, the first coating layer containing an engineering plastic and a solid lubricant; and wherein the bearing characteristic number of the surface of the sliding member facing the fixed member is 8×10 －１０ Bearing characteristics for the friction coefficient at 8 x 10 －９ A sliding part in which the ratio of the coefficient of friction at is 75% or less.

2. The number of bearing characteristics on the surface of the sliding member facing the fixed member is 8 x 10 －１０ Bearing characteristics for the friction coefficient at 8 x 10 －８ 2. The sliding component according to claim 1, wherein the ratio of the coefficient of friction at 3. A sliding component according to claim 1 or 2, wherein the fixed member has a second base and a second coating layer laminated directly or indirectly on the surface of the second base facing the sliding member, and the second coating layer contains an engineering plastic and a solid lubricant.

4. A sliding component according to any one of claims 1 to 3, wherein the viscosity of the liquid is 10,000 mPa·s or less.

5. A sliding component according to any one of claims 1 to 4, wherein at least one of the surface of the first coating layer of the sliding member and the surface of the second coating layer of the fixed member has a pencil hardness of 3H or higher.

6. A compressor or a liquid pump comprising a sliding component according to any one of claims 1 to 5.

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