Refrigerant compressor, cooling system and refrigerator

Abstract

A refrigerant compressor having a compression element comprising sliding components made of metallic materials, wherein a mixed layer is formed by solid-dissolving molybdenum disulfide in at least one of the sliding faces of the sliding components, and a single molybdenum disulfide layer is further formed on the surface of the mixed layer. With this configuration, initial break-in is done using the single layer, and sliding loss is reduced. Even if the single layer peels off, because the molybdenum disulfide of the mixed layer is cleaved at a low friction coefficient, solid lubrication action is attained, the friction coefficient of the sliding section is lowered, and sliding loss is reduced.

Description

TECHNICAL FIELD[0001]The present invention relates to a refrigerant compressor being used mainly for household electric refrigerator-freezers and the like.BACKGROUND ART[0002]In recent years, highly efficient compressors consuming less fossil fuel have been being developed for the protection of global environment.[0003]In a conventional compressor, one of the sliding members constituting a sliding section is made of a nitrided iron-based material treated with manganese phosphate, and the other sliding member is made of anodized aluminum die cast (for example, refer to Japanese Patent Application Laid-open No. Hei 6-117371).[0004]FIG. 14 is a sectional view showing a conventional refrigerant compressor disclosed in Japanese Patent Application Laid-open No. Hei 6-117371. As shown in FIG. 14, in a closed container 1, oil 2 is accumulated at the bottom thereof, and the closed container 1 accommodates an electric driving element 5 comprising a stator 3 and a rotor 4, and also accommodate...

AI Technical Summary

Benefits of technology

[0026]An invention set forth in claim 2 is characterized in that the maximum concentration of the molybdenum disulfide in the mixed layer according to the invention set forth in claim 1 is 5 wt % or more. Hence, the self-lubrication of the molybdenum disulfide of the mixed layer is stabilized, and the friction coefficient is lowered further. For this reason, according to the invention set forth in claim 2, it is possible to suppress metal abrasion on the mixed layer, the base material and the sliding face of the mating sliding component, in addition to the effects of the invention set forth in claim 1, whereby it is possible to provide a refrigerant compressor having high reliability and high efficiency.

[0027]An invention set forth in claim 3 is characterized in that the thickness of the mixed layer according the invention set forth in claim 1 is 0.1 to 2.0 μm. By the setting of the thickness of the mixed layer at 0.1 to 2.0 μm, the solid lubrication action of the molybdenum disulfide of the mixed layer can be attained stably. Hence, according to the invention set forth in claim 3, the friction coefficient of the sliding component is lowered, and sliding loss can be reduced. For this reason, according to the invention set forth in claim 3, it is possible to suppress metal abrasion on the mixed layer, the base material and the sliding face of the mating sliding component, in addition to the effects of the invention set forth in claim 1, whereby it is possible to provide a refrigerant compressor having high reliability and high efficiency.

[0028]An invention set forth in claim 4 is characterized in that the purity of the molybdenum disulfide of the single molybdenum disulfide layer according to the invention set forth in claim 1 is 98% or more. Hence, the amounts of impurities having friction coefficients higher than that of the molybdenum disulfide become very small, whereby the friction coefficient of the single molybdenum disulfide layer can be lowered, and sliding loss can be reduced. For this reason, according to the invention set forth in claim 4, it is possible to suppress metal abrasion on the mixed layer, the base material and the sliding face of the mating sliding component, in addition to the effects of the invention set forth in claim 1, whereby it is possible to provide a refrigerant compressor having high reliability and high efficiency.

[0029]An invention set forth in claim 5 is characterized in that the thickness of the single molybdenum disulfide layer according to the invention set forth in claim 1 is 0.1 to 2.0 μm. Even if the single layer having a thickness of 0.1 to 2.0 μm peels off, the amount of leakage from between the piston and the bore section does not increase excessively, and freezing capacity is not lowered. For this reason, according to the invention set forth in claim 5, it is possible to provide a refrigerant compressor having higher efficiency, in addition to the effects of the invention set forth in claim 1.

[0030]An invention set forth in claim 6 provides the refrigerant compressor set forth in any one of claims 1 to 5, wherein oil is accumulated and a compression element is accommodated in a closed container, the compression element is a reciprocating compression element comprising a crankshaft equipped with a main shaft and an eccentric shaft; a thrust section, one end of which is integrated with the crankshaft and the other end of which is integrated with a bearing section; the bearing section rotatably journaling the main shaft; a cylinder block in which a cylindrical bore section is formed; a piston reciprocating inside the cylindrical bore section; a piston pin disposed in parallel with the eccentric shaft and secured to the piston; and a connecting rod for connecting the eccentric shaft to the piston, and the sliding component made of a metallic material is at least either one of the crankshaft, the thrust section, the cylinder block, the piston, the piston pin, and the connecting rod. With this configuration of the invention set forth in claim 6, initial break-in is done using the single molybdenum disulfide layer. This produces an effect of reducing sliding loss. Even if the single layer peels off and solid-to-solid contact occurs, because the molybdenum disulfide of the mixed layer has a hexagonal closed packing crystal structure, the molybdenum disulfide is cleaved at a low friction coefficient, whereby solid lubrication action is attained. This produces effects of lowering the friction coefficient of the sliding component and reducing sliding loss. For this reason, according to the invention set forth in claim 6, it is possible to suppress metal abrasion on the mixed layer, the base material and the sliding face of the mating sliding component, whereby it is possible to provide a refrigerant compressor comprising a reciprocating compression element and having high reliability and high efficiency.

[0031]An invention set forth in claim 7 provides the refrigerant compressor according to the invention set forth in any one of claims 1 to 5, wherein oil is accumulated and a compression element is accommodated in a closed container, the compression element comprises a crankshaft equipped with a main shaft and an eccentric shaft; a thrust section, one end of which is integrated with the crankshaft and the other end of which is integrated with a bearing section; the bearing section rotatably journaling the main shaft; a cylinder block in which a cylindrical bore section is formed; a piston reciprocating inside the cylindrical bore section; and a connecting rod to which a ball is secured on the side connected to the piston, the piston in which the ball is movably held by crimping constitutes a reciprocating compression element, and the sliding component made of a metallic material is at least either one of the crankshaft, the thrust section, the cylinder block, the piston, and the connecting rod. With this configuration of the invention set forth in claim 7, initial break-in is done using the single molybdenum disulfide layer. This produces an action of reducing sliding loss. Even if the single layer peels off and solid-to-solid contact occurs, because the molybdenum disulfide of the mixed layer has a hexagonal closed packing crystal structure, the molybdenum disulfide is cleaved at a low friction coefficient, whereby solid lubrication action is attained. This produces effects of lowering the friction coefficient of the sliding component and reducing sliding loss. For this reason, according to the invention set forth in claim 7, it is possible to suppress metal abrasion on the mixed layer, the base material and the sliding face of the mating sliding component. As a result, the amount of metal abrasion powder that enters the crimped section between the piston and the ball and is trapped therebetween is reduced. Hence the free movement of the ball cannot be restricted, and it is possible to provide a reciprocating refrigerant compressor comprising a reciprocating compression element and having high reliability and high efficiency.

Problems solved by technology

However, for example, if the sliding members make contact with each other repeatedly at the time of startup or the like during which no oil film is formed between the sliding members, the manganese phosphate layer is abraded and lost, and the base materials of the sliding members may make metallic contact with each other.

As a result, the friction coefficient rises and sliding loss increases in the refrigerant compressor.

If the heat generated from the sliding members increases, abrasion may increase and abnormal abrasion may occur.

This sludge adheres to the inner wall of a capillary tube having a minute flow path, and an expansion valve, being generally used as an expander in a cooling system, and may inhibit the circulation of the refrigerant.

However, according to the specifications, the mixed layer has hardness close to that of the base material, and the effect of initial break-in is hardly obtained.

Hence, sliding loss cannot be reduced, and there is a problem of lowering the efficiency of the compressor.

Additionally, although the mixed layer has self-lubrication action, if the mixed layer or the sliding face of the mating sliding component is abraded, there is a problem of generating metal powder and metallic salts.

However, if the manganese phosphate treatment is carried out on the mixed layer, the surface of the sliding component and the mixed layer formed by solid-dissolving molybdenum disulfide in the surface are corroded and lost because of the chemical reactions carried out during the manganese phosphate treatment according to the chemical reaction formulas: (chemical formula 1), (chemical formula 2) and (chemical formula 3) described below.

For this reason, it is almost impossible to realize the configuration described above.

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