JP6597962B2 - A sliding mechanism, a refrigerant compressor and an air conditioner using the sliding mechanism, and a method for manufacturing the sliding mechanism. - Google Patents

Description

  The present invention relates to a sliding mechanism, and more particularly to a sliding mechanism having seizure resistance and low friction even during low-speed rotation at which the oil film thickness becomes thin, and more particularly suitable for a refrigerant compressor for air conditioning and the like. The present invention relates to a sliding mechanism.

  Sliding members equipped with sliding mechanisms such as refrigerant compressors used in expansion / compression cycles such as air conditioners and rotating bodies of internal combustion engines adjust the surface material of the sliding surface to improve friction resistance and friction loss. Has been done to reduce.

  In recent years, interest in reducing energy consumption has increased, and in the field of automobiles, fuel efficiency has been improved by reducing friction loss of the sliding mechanism. Particularly in an electric vehicle, the cruising distance can be extended by reducing the frictional resistance of a refrigerant compressor for air conditioning to reduce power consumption.

  In-vehicle refrigerant compressors are used not only for high-load operation under hot weather, but also for low-load operation such as anti-fogging at low outside temperatures, so high efficiency in a wide range of rotation from low to high rotation It is required to be.

  However, in the conventional refrigerant compressor using the surface-treated sliding member, the dynamic pressure generation effect is reduced, the oil film thickness is reduced, and the sliding operation is performed in the low speed region where the mixed lubrication region is likely to occur. There is a problem that the friction coefficient in the portion increases and the friction loss cannot be reduced.

  Japanese Patent Application Laid-Open No. 2012-36878 of Patent Document 1 discloses a rotating shaft in which a hard coating having a hardness of 1000 Hv or more such as a diamond-like carbon (DLC) film is formed on a sliding surface of an iron-based material, and polytetrafluoroethylene. A refrigerant compressor using a plain bearing impregnated with a resin material such as (PTFE) is disclosed. And according to the said refrigerant | coolant compressor, it is disclosed that the friction coefficient in the sliding member inside a compressor and the improvement of abrasion resistance can be aimed at.

  Japanese Patent Laid-Open No. 2013-108598 of Patent Document 2 discloses a sliding member in which a sliding surface having a low sliding resistance is formed by eutecting diamond particles on the outermost surface of the plating film on the sliding surface. It is disclosed.

JP 2012-36878 A JP 2013-108598 A

  However, in the thing of patent document 1, since it uses a diamond-like carbon film, it is difficult to obtain sufficient adhesiveness with an aluminum member, and high efficiency by weight reduction etc. is difficult. It is.

  Moreover, in the thing of patent document 2, since it aims at reducing the sliding resistance only by a sliding member, low friction reduction is still not enough.

  The present invention has been made in view of such problems of the prior art, and an object of the present invention is not only a sliding member but also a sliding including a lubricating composition interposed between the sliding members. An object of the present invention is to provide a sliding mechanism capable of reducing the friction of the entire moving mechanism and improving the efficiency of a refrigerant compressor or the like.

  As a result of intensive investigations to achieve the above object, the present inventor combines a sliding member having a specific composite plating layer formed on the sliding surface and a lubricating composition containing a specific lubricating base oil. Thus, the present inventors have found that the frictional resistance can be greatly reduced and have completed the present invention.

  That is, the sliding mechanism of the present invention includes a pair of sliding members that slide through the lubricating composition. At least one of the sliding members has a composite plating layer in which diamond particles are dispersed in a metal film on the sliding surface, and the lubricating composition contains an ester bond (—COO—) and / or an ether bond. A lubricating base oil having (—O—) is included.

  Moreover, the refrigerant compressor of this invention is equipped with the said sliding mechanism, It is characterized by the above-mentioned.

  Furthermore, an air conditioner according to the present invention includes the refrigerant compressor.

  In addition, the manufacturing method of the sliding mechanism of the present invention is a method of manufacturing the sliding mechanism. And depositing a metal plating film on the surface of the sliding member of the sliding mechanism, and dispersing and eutecting the diamond particles in the metal plating film to form the composite plating layer. A compressor is provided.

  According to the present invention, at least one of the pair of sliding members is a sliding member having a composite plating layer in which diamond particles are dispersed in a metal film on the sliding surface, and is interposed between the pair of sliding members. Since the lubricating base oil of the lubricating composition has an ester bond (—COO—) and / or an ether bond (—O—), the frictional resistance can be greatly reduced, and the efficiency of the refrigerant compressor and the like can be greatly improved. A sliding mechanism can be provided.

It is a schematic diagram of a rotary friction and abrasion tester. It is a Stribeck diagram which evaluated the sliding mechanism of the Example and the comparative example.

The sliding mechanism of the present invention will be described in detail.
The sliding mechanism of the present invention comprises a pair of sliding members and a lubricating composition interposed between the sliding members. At least one of the sliding members has a composite plating layer in which diamond particles are dispersed in a metal film on the sliding surface, and the lubricating composition comprises an ester bond (—COO—) and / or an ether. Includes a lubricating base oil having a bond (—O—).

  The reason why the sliding mechanism of the present invention can significantly reduce the frictional resistance is not clarified, but is considered as follows.

In the sliding mechanism of the present invention, the lubricating composition having an ester bond (—COO—) and / or an ether bond (—O—) reacts by a friction reaction due to an input such as an increase in pressure or temperature of the sliding surface. A product is formed. Further, the friction reaction product is adsorbed on the polycrystalline diamond particles in the composite plating layer and stays on the sliding surface to form a friction reaction product film, so that even if the dynamic pressure generation effect is small, the friction reducing effect Is considered to be obtained.

<Lubricating composition>
The lubricating composition of the present invention comprises a lubricating base oil having an ester bond (—COO—) and / or an ether bond (—O—), and contains a refrigerant, an additive or the like as necessary. .

(Lubricating base oil)
The lubricating base oil has an ester bond (—COO—) and / or an ether bond (—O—), and can use a polyol ester (POE) or a polyalkyl glycol (PAG). What is used as refrigerating machine oil used for a compressor can be used.

Since the refrigeration oil is in direct contact with the refrigerant, it has unique performance different from that of mineral oil, and is standardized by JISK2211 and the like.
In other words, refrigeration oil is sent from the compressor together with the refrigerant, circulates through the system, returns to the compressor, and lubricates the compressor. In addition to lubricity, refrigerant solubility, and low-temperature fluidity, the oil in the sealed system Since replacement is not premised, high durability stability and reliability equivalent to the service life of refrigeration and air conditioning equipment are required.

The polyol ester (POE) is an ester of a polyol having a plurality of hydroxyl groups and a fatty acid.
Examples of the polyol include neopentyl glycol, trimethylol ethane, trimethylol propane, trimethylol butane, and pentaerythritol. These can be used in combination of two or more.

The fatty acid is preferably a fatty acid having 5 to 12 carbon atoms, although it depends on the purpose of use of the sliding mechanism. When the number of carbon atoms is small, lubricity may be reduced, and when the number of carbon atoms is increased, compatibility with the refrigerant may be reduced.
The fatty acid may be either a linear fatty acid or a branched fatty acid, but a linear fatty acid is preferable from the viewpoint of lubricity, and a branched fatty acid is preferable from the viewpoint of hydrolysis stability. Furthermore, either a saturated fatty acid or an unsaturated fatty acid may be used.

Examples of the polyol ester (POE) include polyol esters such as trimethylolpropane caprylate, trimethylolpropane pelargonate, pentaerythritol-2-ethylhexanoate, pentaerythritol pelargonate, or a mixture of two or more of these. Can be mentioned.

The polyalkylene glycol (PAG) is obtained by addition polymerization of an alkylene oxide to an alcohol.
Examples of the polyalkylene glycol (PAG) include polypropylene glycol dimethyl ether, polyoxyethylene, polypropylene glycol dimethyl ether, polypropylene glycol monobutyl ether, polypropylene glycol diacetate, or a mixture of two or more of these.

The 40 ° C. kinematic viscosity of the lubricating base oil is preferably 5 mm / s ² or more and 100 mm / s ² or less. Oil film breakage is prevented by being 5 mm / s ² or more, and friction loss can be reduced by being 100 mm / s ² or less. The viscosity index of Jun Nameramoto oil is preferably 10 or more.
In addition, the kinematic viscosity and the viscosity index at 40 ° C. referred to in the present invention are values measured in accordance with JIS K2283, respectively.

Further, the pour point of the Jun Nameramoto oil is preferably -10 ° C. or less, more preferably -20 ° C. or less. In addition, the pour point as used in the field of this invention means the value measured based on JISK2269.

Moreover, the flash point of Jun Nameramoto oil is preferably 120 ° C. or higher, more preferably 200 ° C. or higher. In addition, the flash point as used in the field of this invention means the value measured based on JISK2265.

Polyol ester (POE) is generally used in compressors for refrigerating and air conditioning that are compatible with mixed refrigerants such as R407C and R410A, and polyalkyl glycol (PAG) is generally used in fluorocarbons such as HFC134a. Used in refrigeration and air conditioning compressors that support refrigerants.

(Additive)
The lubricating composition of the present invention can contain additives such as friction modifiers and detergents.

Examples of the friction modifier include fatty acid ester-based ashless friction modifiers and aliphatic amine-based ashless friction modifiers. Specifically, the carbon number is 6-30, preferably 8-24. Particularly preferred examples include fatty acid esters having a linear or branched hydrocarbon group having 10 to 20 carbon atoms, aliphatic amine compounds, and mixtures thereof.
When the carbon number of the ashless friction modifier is 6 to 30, a high friction reduction effect can be obtained.

Specific examples of the linear or branched hydrocarbon group having 6 to 30 carbon atoms include hexyl group, heptyl group, octyl group, nonyl group, decyl group, undecyl group, dodecyl group, tridecyl group, tetradecyl group. Group, pentadecyl group, hexadecyl group, heptadecyl group, octadecyl group, nonadecyl group, icosyl group, henicosyl group, docosyl group, tricosyl group, tetracosyl group, pentacosyl group, hexacosyl group, heptacosyl group, octacosyl group, nonacosyl group, and triacontyl group Alkyl groups such as
In addition, hexenyl group, heptenyl group, octenyl group, nonenyl group, decenyl group, undecenyl group, dodecenyl group, tridecenyl group, tetradecenyl group, pentadecenyl group, hexadecenyl group, heptadecenyl group, octadecenyl group, nonadecenyl group, icocenyl group, heicosenyl group Examples thereof include alkenyl groups such as a dococenyl group, a tricocenyl group, a tetracocenyl group, a pentacocenyl group, a cefacosenyl group, a heptacocenyl group, an octacocenyl group, a nonacosenyl group, and a triaconenyl group.
In addition, the position of the double bond in the alkenyl group is arbitrary.

Examples of the fatty acid ester include esters of a fatty acid having 6 to 30 carbon atoms and an aliphatic monohydric alcohol or aliphatic polyhydric alcohol.
Specifically, glycerol monooleate, glycerol diolate, sorbitan monooleate, sorbitan diolate, and the like can be given as particularly preferable examples.

Examples of the aliphatic amine compound include aliphatic monoamines or their alkylene oxide adducts, aliphatic polyamines, imidazoline compounds, and derivatives thereof.
Specifically, fats such as laurylamine, lauryldiethylamine, lauryldiethanolamine, dodecyldipropanolamine, palmitylamine, stearylamine, stearyltetraethylenepentamine, oleylamine, oleylpropylenediamine, oleyldiethanolamine and N-hydroxyethyloleylimidazoline Amine alkylene compounds, amine alkylene oxide adducts such as N, N-dipolyoxyalkylene-N-alkyl (or alkenyl) (carbon number 6 to 28) of these aliphatic amine compounds, carbon numbers in these aliphatic amine compounds 2 to 30 monocarboxylic acids (fatty acids, etc.) and carboxylic acids such as oxalic acid, phthalic acid, trimellitic acid, pyromellitic acid, etc. one Or neutralized or amidated some or all of both the so-called acid-modified compounds, and the like. Preferable examples include N, N-dipolyoxyethylene-N-oleylamine.

The content of the fatty acid ester-based ashless friction modifier and / or the aliphatic amine-based ashless friction modifier contained in the lubricating composition is not particularly limited, but is 0.05 to 5 based on the total amount of the lubricating composition. It is preferably 3.0% by mass, and more preferably 0.1 to 2.0% by mass.
If the content is less than 0.05% by mass, the friction reducing effect tends to be small, and if it exceeds 3.0% by mass, solubility in the lubricating base oil and storage stability are reduced and precipitates are generated. There is.

Examples of the detergent include a detergent containing polybutenyl succinimide and / or a derivative thereof, and the polybutenyl succinimide is represented by the following formula (1) and formula (2). Compounds.

式（１）、式（２）中、ＰＩＢはポリブテニル基を示し、ｎは１〜５の整数を示す。

In formula (1) and formula (2), PIB represents a polybutenyl group, and n represents an integer of 1 to 5.

The polybutenyl group is obtained from polybutene having a number average molecular weight of 900 to 3500, preferably 1000 to 2000, and the polybutene is a high purity isobutene or a mixture of 1-butene and isobutene, a boron fluoride catalyst or an aluminum chloride catalyst. It is obtained by polymerizing with.
When the number average molecular weight of the polybutenyl group is less than 900, the cleaning effect tends to be poor, and when it exceeds 3,500, the low temperature fluidity may be lowered.
In addition, the polybutene has a small amount of fluorine and chlorine remaining due to the catalyst in the production process by an appropriate method such as an adsorption method or sufficient washing with water, preferably 50 ppm or less, more preferably 10 ppm or less, particularly preferably. It is also possible to use after removing to 1 ppm or less.
Moreover, n of said Formula (1) and Formula (2) is 1-5, and it is preferable that it is an integer of 2-4. It exists in the said range, and it is excellent in cleanliness.

  The method for producing the polybutenyl succinimide is not particularly limited. For example, by reacting polybutenyl succinic acid with polyamines such as diethylenetriamine, triethylenetetramine, tetraethylenepentamine and pentaethylenehexamine. Obtainable. The polybutenyl succinic acid is obtained by reacting the polybutene chlorinated product or polybutene from which chlorine and fluorine are sufficiently removed with maleic anhydride at 100 to 200 ° C.

  Examples of the polybutenyl succinic acid derivative include boron-modified or acid-modified compounds of the compounds represented by the above formulas (1) and (2), and boron-containing polybutenyl succinimides, Boron-containing bispolybutenyl succinimide is preferred.

The boron-modified or acid-modified compound of the polybutenyl succinate is obtained by allowing a boron compound or an oxygen-containing organic compound to act on the compounds represented by the above formulas (1) and (2), thereby remaining amino groups and imino. It is obtained by neutralizing or amidating part or all of one or both of the groups.

Examples of the boron compound include boric acid, borates, and borate esters.
Specifically, examples of the boric acid include orthoboric acid, metaboric acid, and tetraboric acid.
Moreover, as said borate, ammonium borates, such as ammonium salt etc., specifically, ammonium metaborate, ammonium tetraborate, ammonium pentaborate, and ammonium octaborate, are mentioned as a suitable example.
The boric acid ester is an ester of boric acid and preferably an alkyl alcohol having 1 to 6 carbon atoms, more specifically, monomethyl borate, dimethyl borate, trimethyl borate, monoethyl borate, diethyl borate Preferable examples include triethyl borate, monopropyl borate, dipropyl borate, triplypropyl borate, monobutyl borate, dibutyl borate, and tributyl borate.
In addition, the mass ratio “B / N” of the boron content B and the nitrogen content N in the boron-containing polybutenyl succinimide is usually 0.1 to 3, preferably 0.2 to 1.

  Specific examples of the oxygen-containing organic compound include formic acid, acetic acid, glycolic acid, propionic acid, lactic acid, butyric acid, valeric acid, caproic acid, enanthic acid, caprylic acid, pelargonic acid, capric acid, and undecyl acid. , Lauric acid, tridecanoic acid, myristic acid, pentadecanoic acid, palmitic acid, margaric acid, stearic acid, oleic acid, nonadecanoic acid and eicosanoic acid, etc., monocarboxylic acid having 1 to 30 carbon atoms, oxalic acid, phthalic acid, trimellit Examples thereof include polycarboxylic acids having 2 to 30 carbon atoms such as acid and pyromellitic acid and anhydrides or ester compounds thereof, alkylene oxides having 2 to 6 carbon atoms, and hydroxy (poly) oxyalkylene carbonate.

  In the lubricating composition used in the present invention, the content of polybutenyl succinimide and / or a derivative thereof is not particularly limited, but is preferably 0.1 to 15% by mass, and preferably 1.0 to 12% by mass. % Is more preferable. If it is less than 0.1% by mass, the cleaning effect may be poor, and if it exceeds 15%, it is difficult to obtain a cleaning effect corresponding to the content, and the demulsibility tends to deteriorate.

  Moreover, the said lubricating composition can contain the zinc dithiophosphate represented by following General formula (3).

上記式（３）中、Ｒ^４、Ｒ^５、Ｒ^６及びＲ^７は、それぞれ個別に炭素数１〜２４の炭化水素基を示す。

In the above formula ^{(3), R 4, R} 5, R 6 and ^{R 7} are each independently a hydrocarbon group having 1 to 24 carbon atoms.

Examples of the hydrocarbon group include a linear or branched alkyl group having 1 to 24 carbon atoms, a linear or branched alkenyl group having 3 to 24 carbon atoms, and a cycloalkyl group having 5 to 13 carbon atoms. Or a linear or branched alkylcycloalkyl group, an aryl group having 6 to 18 carbon atoms, a linear or branched alkylaryl group, an arylalkyl group having 7 to 19 carbon atoms, and the like. . The alkyl group and alkenyl group may be any of primary, secondary and tertiary.

As said R < ⁴ >, R < ⁵ >, R < ⁶ > and R < ⁷ >, methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, heptyl group, octyl group, nonyl group, decyl group, undecyl group, dodecyl group Alkyl groups such as tridecyl group, tetradecyl group, pentadecyl group, hexadecyl group, heptadecyl group, octadecyl group, nonadecyl group, icosyl group, heicosyl group, docosyl group, tricosyl group and tetracosyl group,
Propenyl group, isopropenyl group, butenyl group, butadienyl group, pentenyl group, hexenyl group, heptenyl group, octenyl group, nonenyl group, decenyl group, undecenyl group, dodecenyl group, tridecenyl group, tetradecenyl group, pentadecenyl group, hexadecenyl group, heptadecenyl group Octadecenyl group such as oleyl group, nonadecenyl group, icocenyl group, hencocenyl group, dococenyl group, tricocenyl group, tetracocenyl group, alkenyl group such as cyclopentyl group, cyclohexyl group and cycloheptyl group,
Methylcyclopentyl group, dimethylcyclopentyl group, ethylcyclopentyl group, propylcyclopentyl group, ethylmethylcyclopentyl group, trimethylcyclopentyl group, diethylcyclopentyl group, ethyldimethylcyclopentyl group, propylmethylcyclopentyl group, propylethylcyclopentyl group, di-propylcyclopentyl group, Propyl ethyl methyl cyclopentyl group, methyl cyclohexyl group, dimethyl cyclohexyl group, ethyl cyclohexyl group, propyl cyclohexyl group, ethyl methyl cyclohexyl group, trimethyl cyclohexyl group, diethyl cyclohexyl group, ethyl dimethyl cyclohexyl group, propyl methyl cyclohexyl group, propyl ethyl cyclohexyl group, Di-propylcyclohexyl group, propyl Tylmethylcyclohexyl, methylcycloheptyl, dimethylcycloheptyl, ethylcycloheptyl, propylcycloheptyl, ethylmethylcycloheptyl, trimethylcycloheptyl, diethylcycloheptyl, ethyldimethylcycloheptyl, propylmethylcyclo Alkyl cycloalkyl groups such as heptyl, propylethylcycloheptyl, di-propylcycloheptyl and propylethylmethylcycloheptyl;
Aryl groups such as phenyl and naphthyl groups;
Tolyl group, xylyl group, ethylphenyl group, propylphenyl group, ethylmethylphenyl group, trimethylphenyl group, butylphenyl group, propylmethylphenyl group, diethylphenyl group, ethyldimethylphenyl group, tetramethylphenyl group, pentylphenyl group, Alkylaryl groups such as hexylphenyl, heptylphenyl, octylphenyl, nonylphenyl, decylphenyl, undecylphenyl and dodecylphenyl;
Examples include arylalkyl groups such as benzyl group, methylbenzyl group, dimethylbenzyl group, phenethyl group, methylphenethyl group, and dimethylphenethyl group.
The hydrocarbon group which R ⁴ , R ⁵ , R ⁶ and R ⁷ can take include all possible linear structures and branched structures, and the position of the double bond of the alkenyl group. The bonding position of the alkyl group to the cycloalkyl group, the bonding position of the alkyl group to the aryl group, and the bonding position of the aryl group to the alkyl group are arbitrary.
Further, among the hydrocarbon groups, when the hydrocarbon group is a linear or branched alkyl group having 1 to 18 carbon atoms, an aryl group having 6 to 18 carbon atoms, or a linear or branched group. Particularly preferred is a branched alkylaryl group.

  Preferred examples of the zinc dithiophosphate include zinc diisopropyldithiophosphate, zinc diisobutyldithiophosphate, zinc di-sec-butyldithiophosphate, zinc di-sec-pentyldithiophosphate, zinc di-n-hexyldithiophosphate, di- Zinc-sec-hexyldithiophosphate, zinc di-n-decyldiophosphate, zinc di-2-ethylhexyldithiophosphate, zinc di-n-decyldithiophosphate, zinc di-n-dodecyldithiophosphate, zinc diisotridecyldithiophosphate and The mixture etc. which concern on these arbitrary combinations are mentioned.

Further, the content of the zinc dithiophosphate is not particularly limited, but may be 0.06% by mass or more and 0.1% by mass or less based on the total amount of the lubricating composition from the viewpoint of exerting a higher friction reduction effect. preferable.
When the content of zinc dithiophosphate exceeds 0.1% by mass, the fatty acid ester-based ashless friction modifier and the aliphatic amine-based ashless friction modifier on the sliding surface of the member coated with the hard carbon thin film There is a possibility that an excellent friction reducing effect may be inhibited.

As a method for producing such zinc dithiophosphate, a conventional method can be arbitrarily adopted, and is not particularly limited. Specifically, hydrocarbon groups corresponding to the above R ⁴ , R ⁵ , R ⁶ and R ⁷ are used. It can be synthesized by reacting the alcohol or phenol possessed with phosphorus pentoxide (P ₂ O ₅ ) to give dithiophosphoric acid and neutralizing it with zinc oxide.
In addition, it cannot be overemphasized that the structure of the said zinc dithiophosphate changes with raw material alcohol to be used.

  In the present invention, two or more kinds of zinc dithiophosphates included in the above (3) may be mixed and used at an arbitrary ratio.

(Refrigerant)
As said refrigerant | coolant, a global warming potential (GWP) can use 0 or a small thing, and can substitute CFC (HFC) and non-CFC (HC).

<Sliding member>
The sliding member of the present invention slides with each other via the lubricating composition, at least one of which has a composite plating layer on the sliding surface, and the composite plating layer contains diamond particles. It is.

  Other sliding members that slide with the sliding member having the composite plating layer include the plating layer provided on the conventional sliding member such as tin plating, nickel plating, and chromium plating in addition to the composite plating layer. However, an aluminum base material on which no plating layer is formed is preferable.

  As the diamond particles contained in the composite plating layer, single crystal type, polycrystalline type, and cluster type nano diamond can be used. Among them, polycrystalline nanodiamond has a substantially spherical structure, and has a small opponent attack and high wear resistance, and therefore can be preferably used for the sliding surface of the sliding member.

  The above-mentioned polycrystalline nano-diamond is artificially detonated by detonation, etc., in which an explosive (mixture of trinitrotoluene and trimethylenetrinitroamine) is exploded and the carbon atoms in the explosive are changed to a diamond structure at high temperature and pressure. Manufactured.

  The polycrystalline nano-diamond has a strong cohesive force and it is difficult to stably exist as primary particles. However, the nanodiamond produced by the detonation method has a structure having amorphous carbon (sp2 carbon) on the surface of diamond (sp3 carbon), and the amorphous carbon is modified with a hydrophilic polymer or an ionic functional group. Can improve dispersibility.

  The hydrophilic polymer increases the steric repulsion force by the polymer chain and stably disperses the diamond particles. Examples of the hydrophilic polymer include polyethylene glycol (PEG) residues and polymethylsiloxane (PDMS) residues.

  The ionic functional group may be either a cationic functional group or an anionic functional group. Examples of the cationic functional group include a functional group that easily binds to a proton under acidic conditions to form onium, and examples thereof include an amino group, a thiol group, a hydroxyl group, and a phosphine group.

The average primary particle size of the diamond particles is preferably 3 nm or more and 10 nm or less, and more preferably 4 nm or more and 6 nm or less. Moreover, it is preferable that the average secondary particle diameter of a diamond particle is 25 nm or more and 50 nm or less.
Ultradispersed diamond (UDD) having an average primary particle size of 4 to 5 nm by the detonation method is sold in the form of a dispersion.

Examples of the metal forming the metal film include nickel (Ni), chromium (Cr), copper (Cu), silver (Ag), tin (Sn), zinc (Zn), iron (Fe), and gold (Au). These may be used as a mixture of two or more. Among these, nickel (Ni) and chromium (Cr) are preferable.

The composite plating layer of the present invention preferably contains 0.1% to 15% by volume of diamond particles.

The composite plating layer may contain fluororesin fine particles.
Examples of the fluororesin fine particles include polytetrafluoroethylene (PTFE), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA), and polyvinylidene fluoride (PVDF). ), Ethylene-chlorotrifluoroethylene copolymer (ECTFE), and ethylene-tetrafluoroethylene copolymer (ETFE). Among these, fine particles made of PTFE are preferable.
The said fluororesin particle | grains can acquire the outstanding sliding characteristic as an average primary particle diameter is 5-50 micrometers.

  There is no restriction | limiting in particular as a base material which comprises the said sliding member, Aluminum, an iron-type material, etc. can be mentioned, It is preferable that it is aluminum.

(Production of composite plating film)
The composite plating film can be formed using a composite plating solution in which diamond fine particles are stably dispersed in a metal plating solution. Specifically, the base material (to-be-plated body) is immersed in the composite plating solution, and by electroless plating treatment in which diamond particles are dispersed and co-deposited in the metal plating film, A composite plating film in which diamond fine particles are uniformly dispersed in nano order can be formed.

The metal plating solution is not particularly limited, but nickel (Ni), chromium (Cr), copper (Cu), silver (Ag), tin (Sn), zinc (Zn), iron (Fe), gold (Au A material containing a metal ion of a metal selected from

The composite plating solution preferably contains a surfactant as a dispersant. By containing the surfactant, it is possible to prevent the electrostatic repulsion force acting between the diamond fine particles from being canceled due to the strong ionic strength of electrolyte ions such as nickel ions, and to suppress aggregation and precipitation.

Examples of the surfactant include anionic and cationic ionic surfactants, and nonionic surfactants. For example, in the case of an ionic surfactant, there are alkylbenzene sulfonate, dialkyldimethylammonium salt, etc., and these may be appropriately selected depending on the ionic functional group introduced on the surface of the diamond fine particles.

  In the case of diamond fine particles into which a hydrophilic polymer is introduced, it is preferable to use a nonionic surfactant. For example, when the hydrophilic polymer is polyethylene glycol, the surface activity of polyethylene glycol mono-4-octylphenyl ether or alkylphenol is used. Agents.

  The surfactant used as the dispersant is preferably a homopolymer or copolymer surfactant having a molecular weight of 30,000 to 200,000. When the molecular weight is larger than 200,000, it causes cross-linking between diamond fine particles, and acts as an aggregating agent rather than a dispersing agent. On the other hand, if the molecular weight is smaller than 30,000, desorption from the diamond fine particles is likely to occur even if the adsorption rate is high, and the effect as a dispersant is reduced.

When the composite plating solution is manufactured by adding the dispersion prepared as described above to the metal plating solution, the amount of diamond fine particles added may be 0.5 to 10 g / liter in the composition of the composite plating solution. preferable.
When plating is performed using a composite plating solution in which the amount of added diamond fine particles is adjusted within this range, the diamond fine particles can be uniformly dispersed in the plating film, and the content of the diamond fine particles is 0.1 to 30 volumes. % Can also be adjusted.

  Examples of the reducing agent used in the composite plating solution include hypophosphites such as sodium hypophosphite, dimethylamine borane, and hydrazine, amine boranes, and hydrazine salts. The concentration of the reducing agent in the composite plating solution varies depending on the type of reducing agent used and the metal to be deposited, but is preferably 20 to 50 g / liter in the composition in the composite plating solution.

  In preparing the composite plating solution, it is preferable to add a complexing agent as long as the dispersed state of the diamond fine particles is not hindered. Complexing agents that can be used in the composite plating solution include citric acid, lactic acid, succinic acid, malonic acid, propionic acid, adipic acid, malic acid, glycolic acid and other organic acids and their water-soluble salts. Of these, one or a combination of two or more can be used. The concentration of the complexing agent to be added is preferably 10 to 40 g / liter in the composition in the composite plating solution.

The sliding mechanism of the present invention can be suitably used as a sliding mechanism for a refrigerant compressor such as a rotary compressor, a scroll compressor, etc. in addition to a sliding member of an internal combustion engine. Used for air conditioners.

  EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited to the following Example.

[Example 1]
By electroless plating, 3% by mass of nanodiamond particles (average primary particle size 4 nm, average secondary particle size 40 nm) and 5% on the sliding surface of a ring-shaped aluminum substrate having a diameter of 35 mm and a width of 8.74 mm, and 5 A nickel-phosphorus composite plating having a thickness of 15 μm in which polytetrafluoroethylene particles of mass% were uniformly dispersed was formed to obtain a ring-shaped sliding member.

  As a mating member on which the ring-shaped sliding member slides, a block-shaped sliding member having a width of 10 mm and a length of 10 mm, in which a tin plating layer having a thickness of 15 μm is formed on the surface of an aluminum base, is used, and a polyol ester (VG90) is used. A sliding mechanism using a lubricating base oil was formed.

[Example 2]
A sliding mechanism was formed in the same manner as in Example 1 except that the block-shaped sliding member was made of an aluminum substrate without forming a tin plating layer.

[Comparative Example 1]
A sliding mechanism was formed in the same manner as in Example 1 except that the ring-shaped sliding member was replaced with one having electroless nickel / phosphorous plating formed on the sliding surface.

[Comparative Example 2]
A sliding mechanism is formed in the same manner as in Example 1 except that the ring-shaped sliding member is replaced with an electroless nickel / phosphorous plating containing 30% by mass of polytetrafluoroethylene particles on the sliding surface. did.

<Evaluation>
An anti-adhesion test and a friction measurement test were performed under the following conditions using the rotary friction and abrasion tester shown in FIG.

(Anti-adhesion test)
The block-shaped sliding member was brought into contact with the ring-shaped sliding member, and the ring-shaped sliding member was rotated at a peripheral speed of 1 m / sec at a lubricating composition temperature of 60 ° C.
Then, the presence or absence of adhesion was measured by a step load method in which 111 N was loaded every minute with a block-shaped sliding member (maximum 890 N). In addition, it was judged that it adhered when the friction force became 30N.

(Friction measurement test)
For those adhesion in the adhesion resistance test did not occur, as in the adhesion resistance test, on the ring-shaped sliding member is brought into contact with the block-shaped slide member, in the lubricating composition temperature 60 ° C., The ring-shaped sliding member was rotated at a peripheral speed of 1 m / sec with a load of 890 N, and the change in the friction force was measured by reducing the peripheral speed to ½ every 3 minutes.
In addition, since the sliding mechanism of Comparative Example 2 was adhered at 330 N, the friction measurement test was not performed.

The results of the friction measurement test are shown in FIG. FIG. 2 is a Stribeck diagram in which the horizontal axis represents the dimensionless number of viscosity (η) / circumferential speed (v) / load (W), and the vertical axis represents the friction force (N).
FIG. 2 shows a state where the oil film is thin on the left side of the horizontal axis and the oil film is thick on the right side.

Examples 1 and 2 having a composite plating layer containing nanodiamond particles on the sliding surface have a smaller friction force than Comparative Example 1 in which nickel / phosphorous plating is formed, and even under sliding conditions where the oil film thickness is reduced. It can be seen that the increase in friction is suppressed and that the efficiency is high in a wide range of rotation.
Further, Example 2 in which the composite plating layer and the aluminum base material were combined had a smaller frictional force than Example 1 in which the composite plating layer and the tin plating layer slide.

In the sliding mechanism of Comparative Example 2, the plating layer on the sliding surface was completely worn out, and strong adhesion marks were observed on both the ring-shaped sliding member and the block-shaped sliding member.
In the sliding mechanism of Comparative Example 1, slight adhesion marks were observed on both sliding members, but in the sliding mechanisms of Examples 1 and 2, only the sliding marks were seen on the block-shaped sliding member. Thus, there was almost no wear on the ring-shaped sliding member side.

Moreover, the following sliding mechanisms were produced and the friction coefficient was measured with the rotary friction wear tester shown in FIG. The evaluation results are shown in Table 1 together with the friction coefficient of Example 2.

[Comparative Example 3]
A sliding mechanism was formed in the same manner as in Example 2 except that the ring-shaped sliding member was replaced with one having electroless nickel / phosphorous plating formed on the sliding surface.

[Example 3]
A sliding mechanism was formed in the same manner as in Example 2 except that the lubricating composition was replaced with a synthetic oil PAO (Poly alpha olefin) containing 1% of an ester-based additive (GMO: Glycerol mono-oleate).

[Comparative Example 4]
A sliding mechanism was formed in the same manner as in Example 3 except that the ring-shaped sliding member was replaced with one having electroless nickel / phosphorous plating formed on the sliding surface.

  When the lubricating composition contains a lubricating base oil having an ester bond or an ether bond, the friction coefficient of Example 2 in which the sliding surface is NiP plating containing nanodiamonds is 0.011, and the sliding surface is nanodiamonds. The friction coefficient is significantly reduced to 1/10 or less of the friction coefficient of 0.123 of Comparative Example 3 which is NiP plating that does not contain Ni.

On the other hand, when the lubricating base oil is a synthetic oil (PAO), even if an additive containing an ester bond is added, the friction coefficient of Comparative Example 4 in which the sliding surface is NiP plating containing nanodiamonds is 0. 020 and the sliding surface is NiP plating that does not contain nano diamonds. The friction coefficient is only reduced to two thirds compared to the friction coefficient of 0.030 of Comparative Example 5. Is not obtained.

From the above results, it can be seen that the composite plating layer containing diamond particles has a significantly reduced friction coefficient when combined with a lubricating base oil having an ester bond or an ether bond.

Claims (16)

A sliding mechanism comprising a pair of sliding members that slide through a lubricating composition,
At least one of the sliding members has a composite plating layer on the sliding surface, and the composite plating layer is a metal film containing diamond particles,
A sliding mechanism, wherein the lubricating composition comprises a lubricating base oil having an ester bond (—COO—) and / or an ether bond (—O—).   The sliding member according to claim 1, wherein the pair of sliding members is a combination of a sliding member whose sliding surface is the composite plating layer and a sliding member whose sliding surface is aluminum. Moving mechanism.   The sliding mechanism according to claim 1 or 2, wherein the lubricating base oil contains a polyol ester (POE) and / or a polyalkyl glycol (PAG). 4. The sliding mechanism according to claim 1, wherein the lubricating base oil has a kinematic viscosity at 40 ° C. of 5 mm / s ² or more and 100 mm / s ² or less. The lubricating composition contains an additive,
The additive is a fatty acid ester ashless friction modifier having a hydrocarbon group having 6 to 30 carbon atoms, an aliphatic amine ashless friction modifier having a hydrocarbon group having 6 to 30 carbon atoms, and polybutenyl succinate The sliding mechanism according to any one of claims 1 to 4, wherein the sliding mechanism is selected from a detergent containing acid imide and / or a derivative thereof and zinc dithiophosphate. The sliding mechanism according to any one of claims 1 to 5 , wherein the lubricating composition contains a refrigerant, and the lubricating base oil is a refrigerating machine oil.   The sliding mechanism according to any one of claims 1 to 6, wherein the composite plating layer contains 0.1 vol% to 15 vol% of diamond particles.   The sliding mechanism according to any one of claims 1 to 6, wherein an average secondary particle size of the diamond particles is 25 nm or more and 50 nm or less.   The sliding mechanism according to any one of claims 1 to 7, wherein an average primary particle size of the diamond particles is 3 nm or more and 10 nm or less.   The sliding mechanism according to any one of claims 1 to 8, wherein the diamond particles have amorphous carbon on the surface.   The sliding mechanism according to any one of claims 1 to 9, wherein the composite plating layer contains polytetrafluoroethylene (PTFE) particles.   The composite plating layer is a metal selected from nickel (Ni), chromium (Cr), copper (Cu), silver (Ag), tin (Sn), zinc (Zn), iron (Fe), and gold (Au) The sliding mechanism according to any one of claims 1 to 10, wherein A sliding mechanism for a refrigerant compressor, wherein the sliding mechanism according to any one of claims 1 to 12 is used for a refrigerant compressor.   A refrigerant compressor comprising the sliding mechanism for a refrigerant compressor according to claim 13.   An air conditioner comprising the refrigerant compressor according to claim 14.   It is a manufacturing method of the sliding mechanism as described in any one of the said Claims 1-12, Comprising: While depositing a metal plating film on the surface of a sliding member, the said diamond particle is disperse | distributed in this metal plating film A method for manufacturing a sliding mechanism, comprising eutectoid forming the composite plating layer.

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