JP2009508029A - Refrigerant compressor, cooling device and refrigerator - Google Patents

Abstract

A compression element having a sliding part made of a metal material is formed, and a mixed layer in which molybdenum disulfide is dissolved is formed on at least one sliding surface of the sliding part, and molybdenum disulfide is further formed on the surface of the mixed layer. In addition to reducing the sliding loss and the separation of the single layer, molybdenum disulfide in the mixed layer is cleaved with a low coefficient of friction to form a solid. Exhibits a lubricating action, lowers the friction coefficient of the sliding part, and reduces the sliding loss.

Description

  The present invention relates to a refrigerant compressor mainly used for household electric refrigerator-freezers and the like.

  In recent years, development of highly efficient compressors that reduce the use of fossil fuels has been promoted from the viewpoint of global environmental protection.

  As a conventional compressor, the sliding member constituting the sliding portion is formed of a sliding material obtained by treating one of the nitriding-treated iron-based materials with manganese phosphate and the other sliding member being anodized aluminum. It is formed by die casting (for example, see Japanese Patent Laid-Open No. 6-117371).

  FIG. 14 shows a cross-sectional view of a prior art refrigerant compressor described in JP-A-6-117371. As shown in FIG. 14, the sealed container 1 stores oil 2 at the bottom, and houses an electric element 5 including a stator 3 and a rotor 4 and a reciprocating compression element 6 driven thereby.

Next, details of the compression element 6 will be described below.
The crankshaft 7 includes a main shaft portion 8 in which the rotor 4 is press-fitted and fixed, and an eccentric shaft 9 formed eccentric to the main shaft portion 8. The crankshaft 7 is provided with an oil supply pump 10. The cylinder block 11 forms a compression chamber 13 composed of a substantially cylindrical bore 12 and is provided with a bearing portion 14 that supports the main shaft portion 8.

  The piston 15 loosely fitted to the bore 12 is connected to the eccentric shaft 9 via a piston pin 16 by a connecting rod 17 which is a connecting means. The end face of the bore 12 is sealed with a valve plate 18.

  The head 19 forms a high-pressure chamber and is fixed to the opposite side of the valve plate 18 from the bore 12. The suction tube 20 is fixed to the sealed container 1 and connected to the low pressure side (not shown) of the refrigeration cycle, and guides a refrigerant gas (not shown) into the sealed container 1. The suction muffler 21 is sandwiched between the valve plate 18 and the head 19.

  The main shaft portion 8 and the bearing portion 14 of the crankshaft 7, the piston 15 and the bore 12, the piston pin 16 and the connecting rod 17, and the eccentric shaft 9 and the connecting rod 17 of the crankshaft 7 form a sliding portion. The sliding member constituting the sliding portion is formed of a sliding material obtained by treating one of the nitriding-treated iron-based materials with manganese phosphate, and the other sliding member is formed of anodized aluminum die cast. Has been.

  Next, the operation of the above configuration will be described. Electric power supplied from a commercial power source (not shown) is supplied to the electric element 5 to rotate the rotor 4 of the electric element 5. The rotor 4 rotates the crankshaft 7, and the eccentric motion of the eccentric shaft 9 drives the piston 15 from the connecting rod 17 of the connecting means via the piston pin 16. Thus, the piston 15 reciprocates in the bore 12, and the refrigerant gas introduced into the sealed container 1 through the suction tube 20 is sucked from the suction muffler 21 and continuously compressed in the compression chamber 13.

  As the crankshaft 7 rotates, the oil 2 is supplied to each sliding portion from the oil supply pump 10 to lubricate the sliding portion, and the oil 2 supplied functions as a seal between the piston 15 and the bore 12. Have

Here, the piston 15 and the bore 12 are loosely fitted with a very narrow clearance in order to reduce leakage loss. As a result, there may be a portion where the piston 15 and the bore 12 partially contact each other depending on variations in the shape and accuracy of the bore 12. However, since one of the sliding members in the sliding part is treated with manganese phosphate with low hardness and density, even if mutual contact occurs, the manganese phosphate at that part will wear out and become compatible with each other's shape (Initial familiarity) is possible. Therefore, sliding loss can be reduced in the sliding portion between the piston 15 and the bore 12.
JP-A-6-117371 International Publication No. 04/055371 Pamphlet

  In the refrigerant compressor described in JP-A-6-117371, the initial compatibility is good because one of the sliding members in the sliding portion uses manganese phosphate treatment with low hardness and density. However, when the sliding parts repeatedly contact with each other in a state where no oil film is generated at the sliding part, for example, at the start-up, the manganese phosphate layer is worn away and metal contact may occur between the base materials. . As a result, in the refrigerant compressor, when the friction coefficient increases and the sliding loss increases or the calorific value further increases, there is a possibility that increased wear and abnormal wear occur.

  In particular, if wear occurs between the piston 15 and the bore 12, the clearance between the piston 15 and the bore 12 increases, and the compressed refrigerant gas may leak from the clearance between the piston 15 and the bore 12, thereby reducing efficiency. It was.

  Further, the metal powder generated by this wear becomes sludge due to metal salt by reacting with the deteriorated oil. This sludge may adhere to the inner wall of the capillary tube and the expansion valve, which are generally employed as an expander in the cooling system, and may cause an inhibition of refrigerant circulation.

As another conventional technique, there is a material in which a mixed layer in which molybdenum disulfide (MoS ₂ ), which is a solid lubricant, is formed as a solid lubricant on the surface of a sliding part as a sliding material for a compressor ( For example, see International Publication No. 04/055371 pamphlet).

  FIG. 15 shows a cross section of a mixed layer in which molybdenum disulfide according to the prior art described in International Publication No. 04/055371 is dissolved.

  As shown in FIG. 15, in a compression element having a sliding part made of a metal material, a mixed layer 33 to which molybdenum disulfide is fixed is formed on the sliding surface of the sliding part. As a result, the speed of the piston 15 becomes zero at the top dead center and the bottom dead center, and even when metal contact occurs with the bore 12, the molybdenum disulfide in the mixed layer 33 formed on the surface of the piston 15 has. The coefficient of friction decreases due to solid lubricity, and sliding loss can be reduced. Further, by forming the fine depression 34 on the surface of the sliding portion, the fine depression 34 functions as a labyrinth seal at the time of compression, and it is possible to reduce leakage loss and improve wear resistance.

  According to the specification described in the pamphlet of International Publication No. 04/055371, the self-lubricating action can be exerted by cleaving molybdenum disulfide in the mixed layer 33 with a low friction coefficient even when solid contact occurs. However, in this specification, the mixed layer has a hardness close to that of the base material, and the effect of initial familiarity is hardly obtained, so there is a problem that the sliding loss cannot be reduced and the efficiency of the compressor is lowered. It was.

  In addition, although it has a self-lubricating action, when the mixed layer or the mating sliding surface is worn, there is still a problem that metal powder is generated and a metal salt is generated.

  Here, for example, a mixed layer in which molybdenum disulfide having the specifications described in International Publication No. 04/055371 is dissolved is formed on the sliding surface. It is conceivable that both merits can be exhibited by performing the manganese phosphate treatment of the specification described. However, when manganese phosphate treatment is performed on the mixed layer, molybdenum disulfide is dissolved by the following chemical reaction formulas (chemical formula 1), (chemical formula 2), and (chemical formula 3) of the sliding portion surface and manganese phosphate treatment. The mixed layer is corroded and lost. For this reason, the above configuration is almost impossible to realize.

2H ₃ PO ₄ + Fe → Fe (H ₂ PO ₄ ) ₂ + H ₂ (Chemical Formula 1)
Me (H ₂ PO ₄ ) ₂ → MeHPO ₄ + H ₃ PO ₄ (Chemical Formula 2)
3MeHPO ₄ → Me ₃ (PO ₄ ) ₂ + H ₃ PO ₄ (Chemical formula 3)

Here, Me is a divalent metal salt (Fe, Mn).
Me (H ₂ PO ₄ ) ₂ : primary phosphate, MeHPO ₄ : secondary phosphate, Me ₃ (PO ₄ ) ₂ : tertiary phosphate

  The present invention solves the above-described conventional problems, and an object of the present invention is to provide a highly reliable and highly efficient refrigerant compressor that can reduce sliding loss.

  In order to solve the above-described conventional problems, the refrigerant compressor of the present invention forms a mixed layer in which molybdenum disulfide is dissolved in at least one sliding surface of a sliding part made of a metal material, and the mixed layer Further, a single layer of molybdenum disulfide is formed on the surface of the substrate. As a result, the single layer of molybdenum disulfide produces initial conformation, reduces sliding loss, suppresses wear of the base material and the mixed layer or the mating sliding surface, and prevents the generation of metal powder. Have. Furthermore, in the refrigerant compressor of the present invention, even if a single layer is peeled off, the structure of molybdenum disulfide in the mixed layer is a dense hexagonal crystal, so even if solid contact occurs, molybdenum disulfide has a low friction coefficient. By cleaving, the solid lubricating action is exerted, the friction coefficient of the sliding portion is lowered, and the sliding loss is reduced.

  In the refrigerant compressor of the present invention, as described above, a mixed layer in which molybdenum disulfide is dissolved is formed on the sliding surface, and a single layer of molybdenum disulfide is further formed on the surface of the mixed layer. A friction coefficient can be reduced, and a highly reliable and highly efficient refrigerant compressor can be provided. Further, in the refrigerant compressor of the present invention, since generation of metal wear powder on the mixed layer, base material, and mating sliding surface can be suppressed, metal salt due to metal wear powder and deteriorated oil is reduced, and the refrigerant path Even if a fine path such as a capillary tube or an expansion valve is provided, blockage of the fine path by a metal salt can be prevented.

  The invention according to claim 1 has a compression layer having a sliding component formed of a metal material, and a mixed layer in which molybdenum disulfide is dissolved in at least one sliding surface of the sliding component. And a single layer of molybdenum disulfide is further formed on the surface of the mixed layer. Thus, according to the first aspect of the present invention, the molybdenum disulfide in a single layer has the effect of reducing the friction coefficient due to the self-lubricating action of molybdenum disulfide and reducing the sliding loss. Further, according to the first aspect of the present invention, even if a single layer is peeled off, the structure of molybdenum disulfide in the mixed layer is a dense hexagonal crystal, so that even if solid contact occurs, molybdenum disulfide has a low friction coefficient. By cleaving at, it exerts a solid lubricating action. As a result, the friction coefficient of the sliding portion is lowered and the sliding loss can be reduced. Therefore, according to the first aspect of the invention, metal wear of the mixed layer, the base material, and the mating sliding surface is suppressed. Thus, a highly reliable and highly efficient refrigerant compressor can be provided.

  The invention according to claim 2 is the invention according to claim 1, wherein the maximum concentration of molybdenum disulfide in the mixed layer is 5 wt% or more, and the self-lubricating property of molybdenum disulfide in the mixed layer is stabilized, and the friction The coefficient further decreases. Therefore, according to the invention described in claim 2, in addition to the effect of the invention described in claim 1, it is possible to further suppress metal wear of the mixed layer, the base material, and the mating sliding surface, and high reliability. In addition, a highly efficient refrigerant compressor can be provided.

  The invention according to claim 3 is the invention according to claim 1, wherein the thickness of the mixed layer is 0.1 μm to 2.0 μm, and the thickness of the mixed layer is secured to 0.1 μm to 2.0 μm. Then, the solid lubricating action of molybdenum disulfide in the mixed layer can be stably exhibited. For this reason, the invention according to claim 3 can reduce the friction loss of the sliding portion and reduce the sliding loss. Therefore, according to the invention described in claim 3, in addition to the effect of the invention described in claim 1, it is possible to further suppress metal wear of the mixed layer, the base material, and the mating sliding surface, and high reliability. In addition, a highly efficient refrigerant compressor can be provided.

  The invention according to claim 4 is the invention according to claim 1, wherein the purity of molybdenum disulfide forming the single layer of molybdenum disulfide is 98% or more, and usually has a higher friction coefficient than molybdenum disulfide. Since the amount of impurities having a very small amount, the friction coefficient of a single layer of molybdenum disulfide can be reduced, and sliding loss can be reduced. Therefore, according to the invention described in claim 4, in addition to the effect of the invention described in claim 1, metal wear of the mixed layer, the base material, and the mating sliding surface can be further suppressed. A highly efficient refrigerant compressor can be provided.

  The invention according to claim 5 is the invention according to claim 1, wherein the thickness of the single layer of molybdenum disulfide is 0.1 μm to 2.0 μm, and the single layer is peeled off If the thickness of the single layer is 0.1 μm to 2.0 μm, the amount of leakage from the piston / bore does not increase extremely, so that the refrigerating capacity does not decrease. Therefore, according to the invention described in claim 5, in addition to the effect of the invention described in claim 1, a further highly efficient refrigerant compressor can be provided.

  According to a sixth aspect of the present invention, in the invention according to any one of the first to fifth aspects, oil is stored in a sealed container and a compression element is accommodated, and the compression element has a main shaft and an eccentric shaft. A crankshaft provided, a thrust portion formed integrally with the crankshaft and the other integrally formed with the bearing portion, a bearing portion rotatably supporting the main shaft, and a cylinder block forming a cylinder A reciprocating-type compression element comprising: a piston that reciprocates in the cylinder; a piston pin that is disposed in parallel with the eccentric shaft and that is fixed to the piston; and a connecting rod that connects the eccentric shaft and the piston. The sliding parts formed of a metal material include the crankshaft, the thrust part, the cylinder block, the piston, and the piston. Tonpin, and at least one of said connecting rod. For this reason, the invention described in claim 6 has an effect of reducing initial loss due to molybdenum disulfide in a single layer and reducing sliding loss. Even if the single layer is peeled off, the mixed layer Since the structure of molybdenum disulfide is a dense hexagonal crystal, molybdenum disulfide is cleaved with a low friction coefficient even when solid contact occurs, thereby exhibiting a solid lubricating action. Accordingly, the friction coefficient of the sliding portion is lowered, and the effect of reducing the sliding loss is obtained. Therefore, according to the invention described in claim 6, metal wear of the mixed layer, the base material, and the mating sliding surface is reduced. A refrigerant compressor having a reciprocating compression element that can be suppressed and has high reliability and high efficiency can be provided.

  The invention according to claim 7 is the invention according to any one of claims 1 to 5, wherein oil is stored in a sealed container and a compression element is accommodated, and the compression element has a main shaft and an eccentric shaft. A crankshaft provided, a thrust portion formed integrally with the crankshaft and the other integrally formed with the bearing portion, a bearing portion rotatably supporting the main shaft, and a cylinder block forming a cylinder And a piston that reciprocates in the cylinder, and a connecting rod that fixes a ball on the connecting side of the piston, the piston forms a reciprocating compression element that fixes the ball by caulking, and a metal material The sliding parts constituted by the crankshaft, the thrust part, the cylinder block, the piston, and the connecting rod At least is one either. For this reason, the invention described in claim 7 has an effect of reducing initial loss due to molybdenum disulfide in a single layer and reducing sliding loss. Even if the single layer is peeled off, the mixed layer Since the structure of molybdenum disulfide is a dense hexagonal crystal, molybdenum disulfide is cleaved with a low friction coefficient even when solid contact occurs, thereby exhibiting a solid lubricating action. Accordingly, since the friction coefficient of the sliding portion is lowered and the sliding loss is reduced, according to the seventh aspect of the invention, the metal wear of the mixed layer, the base material, and the mating sliding surface is reduced. Along with this, the amount of metal wear powder entering the piston and ball caulking portion is reduced and the amount of biting is reduced, so that obstruction can be prevented and a highly reliable and efficient reciprocating compression element. A refrigerant compressor having the above can be provided.

  According to an eighth aspect of the present invention, in the invention according to any one of the first to fifth aspects, oil is stored in a sealed container and a compression element is accommodated, and the compression element has a shaft having an eccentric portion. A cylinder that forms a compression chamber concentric with the rotation center of the shaft, a rolling piston that is fitted in the eccentric portion and rolls in the compression chamber, and is in pressure contact with the rolling piston to move through the compression chamber. The vane that partitions the high-pressure side and the low-pressure side, and both side surfaces of the cylinder are sealed, and the main bearing on the electric element side and the auxiliary bearing on the counter-electric element side that support the shaft are fixed to one end of the shaft. A rolling piston type compression element having an oil supply spring and an oil supply pipe having one end opened in the oil and containing the oil supply spring is formed, and a metal Sliding component formed by the charges, the shaft, the cylinder, the rolling piston, said vane, said main bearing, said auxiliary bearing, the oil supply spring, and said at least one of the oil supply pipe. For this reason, the invention described in claim 8 has the effect of causing initial familiarity and reducing sliding loss due to the molybdenum disulfide of the single layer, and even if the single layer peels off, the mixed layer Since the structure of molybdenum disulfide is dense hexagonal, even if solid contact occurs, molybdenum disulfide cleaves with a low coefficient of friction and exhibits a solid lubricating action. Accordingly, the friction coefficient of the sliding portion is lowered, and the effect of reducing the sliding loss is obtained. Therefore, according to the invention described in claim 8, metal wear of the mixed layer, the base material, and the mating sliding surface is reduced. A refrigerant compressor having a rotary compression element that can be suppressed and has high reliability and high efficiency can be provided.

  The invention described in claim 9 is a cooling device comprising the refrigerant compressor according to any one of claims 1 to 8, and at least one of a capillary tube and an expansion valve in an expander. In the invention according to claim 9, since metal wear powder discharged from the compressor is small, metal wear powder and metal salt due to deteriorated oil are formed on the inner surface of the capillary tube, which is a fine path, and on the fine path of the expansion valve. It is possible to provide a highly reliable cooling device in which the amount of adhesion is reduced and the circulation of the refrigerant is prevented from being hindered.

  The invention according to claim 10 employs at least one of a finer capillary tube and an expansion valve than a general refrigerator warehouse or a commercial refrigerator with a large amount of refrigerant circulation, for example, a household refrigerator It is used for. In the invention according to claim 10, since the cooling device according to claim 9 is provided, the metal wear powder discharged from the compressor is small, so the inner surface of the capillary tube, which is a fine path, and the expansion valve This reduces the amount of metal wear powder and metal salt due to deteriorated oil adhering to the fine path, prevents the circulation of the refrigerant, and provides a highly reliable refrigerator for home use, for example.

(Embodiment 1)
1 is a cross-sectional view of a refrigerant compressor according to Embodiment 1 of the present invention, FIG. 2 is an enlarged view of part A in FIG. 1, FIG. 3 is an enlarged view of part B in FIG. 2, and FIG. FIG. 5 is a characteristic diagram showing the relationship between the clearance of the piston / bore and the refrigerating capacity in the same embodiment, and FIG. 6 is a concentration distribution diagram of molybdenum disulfide in the same embodiment. FIG. 7 is a characteristic diagram showing the relationship between the molybdenum disulfide concentration and the efficiency in the same embodiment, FIG. 8 is a connecting rod assembly diagram in which the ball fixed to the connecting rod by the piston in the same embodiment is caulking freely fixed, FIG. 9 is a configuration diagram of the household refrigerator in the same embodiment, and FIG. 10 is a cross-sectional view of the expansion valve in the first embodiment.

  1, 2, and 3, the sealed container 101 is filled with a refrigerant gas 102 made of R600a, and oil 103 is stored at the bottom of the sealed container 101. The sealed container 101 houses an electric element 106 including a stator 104 and a rotor 105, and a reciprocating compression element 107 driven by the electric element 106.

Details of the compression element 107 will be described below.
The crankshaft 108 has a main shaft 109 into which the rotor 105 is press-fitted and fixed, and an eccentric shaft 110 formed eccentric to the main shaft 109. An oil supply pump 111 communicating with the oil 103 is provided at the lower end of the crankshaft 108. A cylinder block 112 made of cast iron forms a bearing portion 114 that supports a substantially cylindrical bore 113 and a main shaft 109.

  Further, the rotor surface 105 is formed on the rotor 105, and the upper end surface of the bearing portion 114 is a thrust portion 122. A thrust washer 124 is inserted between the flange surface 120 and the thrust portion 122 of the bearing portion 114. A thrust bearing portion 126 is configured by the flange surface 120, the thrust portion 122, and the thrust washer 124.

  The piston 132 loosely fitted in the bore 113 while maintaining a certain amount of clearance is made of an iron-based material, forms a compression chamber 134 together with the bore 113, and is eccentric by a connecting rod 138 as a connecting means via a piston pin 137. The shaft 110 is connected. The end surface of the bore 113 is sealed with a valve plate 139.

  The head 140 forms a high-pressure chamber and is fixed to the opposite side of the valve plate 139 from the bore 113. A suction tube (not shown) is fixed to the sealed container 101 and connected to the low-pressure side (not shown) of the refrigeration cycle, and guides the refrigerant gas 102 into the sealed container 101. The suction muffler 142 is sandwiched between the valve plate 139 and the head 140.

  The piston 132 and the bore 113, the main shaft 109 and the bearing portion 114, the thrust portion 122 and the thrust washer 124, the piston pin 137 and the connecting rod 138, and the eccentric shaft 110 and the connecting rod 138 form a sliding portion. At least one of the sliding portions is formed with a mixed layer 150 in which molybdenum disulfide is dissolved on the surface of the base material, and a single layer 160 of molybdenum disulfide is further formed on the surface of the mixed layer 150. .

Here, the piston 132 will be described in detail as an example.
Of the sliding portions formed by the piston 132 and the bore 113, the mixed layer 150 in which molybdenum disulfide is dissolved in the surface of the iron-based material that is the base material on the sliding portion surface of the piston 132, and this mixing A single layer 160 of molybdenum disulfide is further formed on the surface of the layer 150. More preferably, the purity of molybdenum disulfide is 98% or more, the thickness of the single layer 160 of molybdenum disulfide is 0.1 μm to 2.0 μm, and the thickness of the mixed layer 150 is 0.1 μm to 2.0 μm. The maximum concentration of molybdenum disulfide in the mixed layer 150 is 5 wt% or more and 50 wt% or less.

  In the first embodiment of the present invention, the purity of the mixed layer 150 in which molybdenum disulfide is dissolved and a single layer 160 of molybdenum disulfide on the surface of the mixed layer 150 is 98% or more. A method is used in which molybdenum disulfide grains are collided with a sliding surface of a metal, which is a base material of a sliding component, at a certain speed or higher.

At this time, the projection pressure of molybdenum disulfide is preferably 1.0 MPa to 1.5 MPa. The thermal energy generated at the time of collision by this method diffuses oxygen on the surface of the base material to form a single layer 160 of molybdenum disulfide, and part of the molybdenum disulfide particles dissolve into the base material due to collision of the molybdenum disulfide grains. It has been found that the mixed layer 150 in which molybdenum disulfide is dissolved and the single layer 160 of molybdenum disulfide can be simultaneously formed by metal bonding.
The piston 132 and the bore 113 are loosely fitted with a very narrow clearance, for example, a clearance dimension of about 5 μm to 15 μm in diameter to reduce leakage loss.

The operation of the refrigerant compressor according to Embodiment 1 configured as described above will be described.
Electric power supplied from a commercial power source (not shown) is supplied to the electric element 106 to rotate the rotor 105 of the electric element 106. The rotation of the rotor 105 rotates the crankshaft 108 and causes the eccentric shaft 110 to move eccentrically. The eccentric movement of the eccentric shaft 110 drives the piston 132 from the connecting rod 138 of the connecting means via the piston pin 137, so that the piston 132 reciprocates in the bore 113. As a result, the refrigerant gas 102 introduced into the sealed container 101 through the suction tube (not shown) is sucked from the suction muffler 142 and compressed in the compression chamber 134.

As the crankshaft 108 rotates, the oil 103 is supplied to each sliding portion from the oil supply pump 111 to lubricate the sliding portion, and the supplied oil 103 functions as a seal between the piston 132 and the bore 113. .
In this sliding operation, since the clearance between the piston 132 and the bore 113 is very narrow, there may be a part that causes mutual contact depending on variations in the shape and accuracy of the piston 132 and the bore 113. In Embodiment 1, since the molybdenum disulfide of the single layer 160 has a property of being easily cleaved, the initial conformability to the shape of the sliding partner is good. As a result, the molybdenum disulfide in the single layer 160 at the site where mutual contact occurs wears out and fits, so that sliding loss can be reduced and a highly efficient refrigerant compressor can be provided.

Here, the relationship between the amount of leakage from the piston 132 and the bore 113 and the refrigerating capacity will be described with reference to FIG.
The horizontal axis in FIG. 5 indicates the clearance between the piston 132 and the bore 113, and the vertical axis indicates the refrigeration capacity.

From the results shown in FIG. 5, when the specified clearance range is A to B μm, the refrigeration capacity suddenly decreases from around B + 4 μm.
Therefore, by forming the thickness of the single layer 160 on the surface of the sliding portion of the piston 132 to be 0.1 μm to 2.0 μm, even if the single layer 160 of molybdenum disulfide is peeled off during operation, the piston 132 The clearance between the bore 113 and the bore 113 is only increased by 4.0 μm at the maximum. As a result, in the configuration of the first embodiment, the amount of leakage from between the piston 132 and the bore 113 does not increase excessively, and the refrigeration capacity does not extremely decrease. The refrigerant compressor provided with can be provided.

Next, in the refrigerant compressor according to the first embodiment of the present invention, an effect obtained by forming the single layer 160 of molybdenum disulfide and the mixed layer 150 will be described.
When the piston 132 is positioned at the top dead center and the bottom dead center, the speed becomes 0 m / s, and no hydraulic pressure is theoretically generated, and no oil film is formed. For this reason, metal contact often occurs at the top dead center and the bottom dead center.

Further, in the refrigerant compressor, when the piston 132 is near the top dead center, the piston 132 receives a large compressive load due to the compressed high-pressure refrigerant. This compressive load is transmitted to the crankshaft 108 via the stone pin 137 and the connecting rod 138, and the crankshaft 108 is pressed and inclined by the piston 132 near the top dead center. The inclination of the crankshaft 108 becomes a force for inclining the piston 132 in the bore 113. As a result, twisting with the bore 113 occurs at one end of the upper end surface of the piston 132 and the other end of the lower end surface. Due to this twisting, the piston 132 slides with the bore 113 and wear occurs. In particular, in the case of the cantilever bearing refrigerant compressor shown in the first embodiment, since the inclination of the crankshaft 108 becomes large, this twist appears prominently.
As a result, the single layer 160 of molybdenum disulfide is worn away, and the mixed layer 150 may be exposed on the surface, which may become a sliding surface.

In Embodiment 1, since the structure of molybdenum disulfide in the mixed layer 150 is a dense hexagonal crystal and the molecular size is as small as about 6 × 10 ⁻⁴ μm, it is cleaved with a low friction coefficient. Therefore, even if metal contact occurs between the piston 132 and the bore 113, the friction coefficient of the sliding portion is lowered and the sliding loss is reduced, so that a highly reliable refrigerant compressor can be provided. .

FIG. 6 shows the concentration distribution of molybdenum disulfide formed on the surface of the sliding portion of the piston 132 employed in the first embodiment of the present invention.
In general, an energy dispersive X-ray analyzer is used for measuring the concentration of molybdenum disulfide formed on the surface of the sliding portion of the piston 132 in FIG. This energy dispersive X-ray analyzer will be briefly described.

  Electrons irradiated to the sliding portion of the piston 132 from the energy dispersive X-ray analyzer enter from the sliding portion surface to a certain depth and generate characteristic X-rays. Characteristic X-rays means that when electrons at a high energy level are transferred due to vacancies formed by electrons that have penetrated to a certain depth and electrons that travel around the nucleus are ejected out of the atoms, X It was generated as a line.

  The energy dispersive X-ray analyzer can analyze the constituent elements on the surface of the sliding part of the piston 132 using this characteristic X-ray, so the concentration of molybdenum disulfide formed on the surface of the sliding part is measured. can do. Since the maximum concentration of molybdenum disulfide in the mixed layer 150 is obtained near the outermost surface, it can be detected by measuring this.

  As shown in FIG. 6, the mixed layer 150 containing molybdenum disulfide has a thickness of 0.1 μm to 2.0 μm and a maximum concentration of 5 to 20 wt%. When the molybdenum disulfide of the mixed layer 150 is thus formed, the self-lubricating property of the molybdenum disulfide is stabilized and the friction coefficient is further reduced.

  Next, the maximum concentration of molybdenum disulfide in the mixed layer 150 and the efficiency of the refrigerant compressor will be described in detail with reference to FIG. FIG. 7 shows the relationship between the maximum concentration of molybdenum disulfide in the mixed layer 150 in FIG. 3 and the efficiency (COP: coefficient of performance) of the refrigerant compressor. The refrigerant compressor that has been operated to some extent is used. As described above, the oblique piston 132 moves in the bore 113, and one end of the upper end surface of the piston 132, the other end of the lower end surface, and the bore The one in which the mixed layer 150 of the piston 132 is a sliding surface by being twisted with 113 is used.

  As shown in FIG. 7, when the maximum concentration of molybdenum disulfide in the mixed layer 150 exceeds 5 wt%, the efficiency of the refrigerant compressor is rapidly improved. The efficiency of the refrigerant compressor is almost constant from the point where it exceeds 15 wt%. Therefore, it is considered that the self-lubricating property of molybdenum disulfide is stabilized if the maximum concentration of molybdenum disulfide in the mixed layer 150 is at least 5 wt% or more.

On the other hand, in order to increase the maximum concentration of molybdenum disulfide in the mixed layer 150, it is necessary to make the molybdenum disulfide grains collide with the metal sliding surface for a long time, that is, with many molybdenum disulfide grains. For this reason, considering the cost and productivity of molybdenum disulfide, it is practical to keep the maximum concentration at about 20 wt%.
Therefore, in Embodiment 1, the maximum concentration of molybdenum disulfide in the mixed layer 150 is controlled between 5 wt% and 20 wt%.

  As described above, in the first embodiment of the present invention, the constant speed compressor has been described. As the speed of the refrigerant compressor progresses with the inverter, especially in ultra-low speed operation at a frequency of less than 20 Hz, it becomes more difficult to establish fluid lubrication and it is easy to cause metal contact. Become.

  In the first embodiment of the present invention, a mixed layer 150 in which molybdenum disulfide is dissolved is formed on the surface of the sliding portion of the piston 132, and a single layer 160 of molybdenum disulfide is further formed on the surface of the mixed layer 150. It was explained in the configuration in which is formed. However, in the refrigerant compressor of the present invention, the mixed layer 150 and the single layer 160 of molybdenum disulfide may be formed on the sliding surface of the bore 113, or may be formed on both the piston 132 and the bore 113. May be. Thus, by forming the mixed layer 150 and the single layer 160 of molybdenum disulfide on both sliding parts, higher wear resistance can be obtained.

  In the first embodiment of the present invention, a mixed layer 150 in which molybdenum disulfide is dissolved is formed on the surface of the sliding portion of the piston 132, and a single layer 160 of molybdenum disulfide is further formed on the surface of the mixed layer 150. I gave a detailed example of what I did. However, the main shaft 109 and the bearing portion 114 of the crankshaft 108 that form sliding portions with each other, the flange surface 120 and the thrust washer 124 of the rotor 105, the thrust portion 122 and the thrust washer 124 on the upper end surface of the bearing portion 114, In the sliding portion of the piston pin 137 and the connecting rod 138 and the eccentric shaft 110 and the connecting rod 138, the same excellent effect can be obtained by forming the mixed layer 150 and the single layer 160 of molybdenum disulfide. .

  In the first embodiment of the present invention, the thrust bearing portion 126 is configured by the flange surface 120, the thrust portion 122, and the thrust washer 124. However, the thrust bearing portion 126 is formed between the main shaft 109 of the crankshaft 108 and the eccentric shaft 110. In the case where a thrust bearing is constituted by the thrust surface 172 of the crankshaft 108 provided on the opposite eccentric shaft 110 side of the flange portion 170 and the thrust portion 122 of the bearing portion 114, the same excellent effect can be obtained.

Moreover, the connecting rod 183 which fixed the ball | bowl 182 was provided in the side connected with the piston 181 shown in FIG. 8, and the piston 181 was comprised so that the ball | bowl 182 could be caulking freely fixed. In the case of a connection specification generally called a ball joint, metal wear powder enters this caulking floating fixing part, and the amount of biting is reduced, so that the floating inhibition can be prevented and high reliability is achieved. And the high efficiency of the initial stage of manufacture can be maintained.
FIG. 8 shows a specification in which a resin 184 is sandwiched between the piston 181 and the ball 182 as an inclusion for smooth sliding.

  The household refrigerator described in FIG. 9 employs a capillary tube 188 as an expander. The temperature of the freezer compartment ensures the Forster performance in accordance with Japanese Industrial Standards (JIS) and maintains −18 ° C., so that the vacuum pressure of the capillary tube 188 is increased so that the temperature of the evaporator 196 is about −30 ° C. In other words, the inner diameter is designed to be smaller than 1 mm. Adherence of foreign matter to a fine path typified by the capillary tube 188 and a refrigerant path in the high-temperature compressor 197 causes a significant decrease in cooling capacity. For this reason, in a domestic refrigerator that is a durable consumer goods for 10 years or more, the contamination of foreign matters during production is severely restricted, and refrigerant, oil purity, residual moisture regulation, processing oil regulation, etc. are provided. Furthermore, since the remaining air causes the generation of foreign matter due to oxidation, it is evacuated to a high vacuum and the refrigerant is hermetically sealed.

  Next, the flow of the refrigerant will be described. The refrigerant is compressed by the compressor 197, dissipated heat through the condenser 198, decompressed by the capillary tube 188, absorbed by the evaporator 196 in the refrigerator 199, and then circulated to the compressor 197.

  At the inlet (not shown) and outlet (not shown) of the capillary tube, the refrigerant flows in a complicated manner with a gas-liquid mixed flow, so that foreign substances that are difficult to dissolve in oil generally adhere to the inlet and outlet, and the refrigerant flows. Impairs circulation. In the household refrigerator 195 according to the first embodiment, since foreign matter is strictly restricted during production, the foreign matter hardly adheres to the inlet or outlet of the capillary tube as described above. In addition, in the household refrigerator configured as described above, there is less metal wear powder, and accordingly, the amount of metal wear powder and metal salt due to deteriorated oil adheres to the refrigerant path, and also adheres to the refrigerant path. Since the amount of foreign matter to be suppressed can be suppressed to a very low level, it is possible to provide a highly reliable household refrigerator that does not decrease the refrigerant circulation rate.

  Further, in the first embodiment, the capillary tube 188 is employed, but even when the expansion valve 189 shown in FIG. 10 is employed, it is possible to prevent the refrigerant circulation inhibition due to the foreign matter adhering to the valve seat surface 190, An excellent effect can be obtained.

(Embodiment 2)
11 is a cross-sectional view of the refrigerant compressor according to Embodiment 2 of the present invention, FIG. 12 is a cross-sectional view taken along line CD in FIG. 11, and FIG. 13 is an enlarged view of a portion E in FIG.
11, 12, and 13, an airtight container 201 contains an electric element 204 including a stator 202 and a rotor 203, and a rolling piston type compression element 205 driven by the electric element 204 together with oil 206. Yes.

  The compression element 205 includes a shaft 210 having an eccentric portion 207, a main shaft portion 208, and a sub shaft portion 209, a cylinder 212 forming a compression chamber 211, and both end surfaces of the cylinder 212, and the main shaft portion 208 and the sub shaft. A main bearing 213 and a sub-bearing 214 that pivotally support the portion 209, a rolling piston 215 that is loosely fitted in the eccentric portion 207 and rolls in the compression chamber 211, and is inserted into the rolling piston 215 so that the compression chamber 211 is placed on the high-pressure side. And a plate-like vane 216 for partitioning to the low-pressure side. A rotor 203 is fixed to the main shaft portion 208.

  The oil pump 217 fixed to the sub-bearing 214 includes an oil supply pipe 220 and an oil supply spring 222 that is loosely fitted to the oil supply pipe 220. The oil pump 217 supplies oil 206 to sliding portions formed by the eccentric portion 207 and the rolling piston 215, the main shaft portion 208 and the main bearing 213, and the sub shaft portion 209 and the sub bearing 214.

  In the second embodiment, a mixture in which molybdenum disulfide is dissolved in a base iron (Fe) -based material which is a sliding surface of the eccentric portion 207, the main shaft portion 208, and the sub shaft portion 209 of the shaft 210 is mixed. A layer 224 is formed, and a single layer 228 of molybdenum disulfide is further formed on the surface of the mixed layer 224.

  More preferably, the purity of molybdenum disulfide is 98% or more, the thickness of the single layer of molybdenum disulfide 228 is 0.1 μm to 2.0 μm, and the thickness of the mixed layer 224 is 0.1 μm to 2.0 μm. The maximum concentration of molybdenum disulfide in the mixed layer 224 is 5 wt% or more and 50 wt% or less.

About the refrigerant | coolant compressor of Embodiment 2 comprised as mentioned above, the operation | movement is demonstrated.
As the rotor 203 rotates, the shaft 210 rotates and the rolling piston 215 loosely fitted in the eccentric portion 207 rolls in the compression chamber 211. Thereby, the volume of the high-pressure side and the low-pressure side of the compression chamber 211 continuously changes in volume, and the refrigerant gas is continuously compressed. Further, the compressed refrigerant gas is discharged into the sealed container 201, and the inside of the sealed container 201 becomes a high-pressure atmosphere. Further, since the inside of the sealed container 201 is at a high pressure, the atmospheric pressure in the sealed container 201 acts as a back pressure on the vane 216, and the tip of the vane 216 is pressed against the outer peripheral surface of the rolling piston 215.

Further, the oil supply spring 222 loosely fitted in the oil supply pipe 220 with the rotation of the shaft 210 continuously supplies the oil 206 to each sliding portion.
In the rolling piston type refrigerant compressor, since the rolling piston 215 is freely loosely fitted to the eccentric portion 207, the relative speed between the rolling piston 215 and the eccentric portion 207 is the main shaft portion 208, the main bearing 213, and the auxiliary shaft portion. It becomes small compared with the relative speed between 209 and the sub bearing 214. This means that the Sommerfeld number S (Formula 1) indicating the characteristics of the journal bearing obtained from the bearing radius R, the radial clearance C, the speed N, the oil viscosity μ, and the surface pressure P is reduced, and sliding lubrication is achieved. This is an unfavorable condition in which upper metal contact is likely to occur.

S = μ × N / P × (R / C) ² (Formula 1)

  Generally, in a rolling piston type refrigerant compressor, since the inside of the hermetic container 201 becomes a condensation pressure, the internal pressure is high and the refrigerant is likely to be dissolved in the oil 206. This is to reduce the viscosity of the oil, to reduce the Sommerfeld number S (Equation 1) indicating the characteristics of the journal bearing described above, which is a disadvantageous condition for sliding lubrication.

  However, a mixed layer 224 in which molybdenum disulfide is dissolved is formed on the surface of the sliding portion of the eccentric portion 207, the main shaft portion 208, and the auxiliary shaft portion 209 of the shaft 210, and molybdenum disulfide is further formed on the surface of the mixed layer 224. By forming the single layer 228, the molybdenum disulfide of the single layer 228 is very easy to cleave even under disadvantageous sliding lubrication conditions where the Sommerfeld number S (Equation 1) is small. Therefore, the initial conformability to adapt to the shape of the sliding partner is improved. As a result, the molybdenum disulfide in the single layer 228 at the site of mutual contact wears out and fits, so the rolling piston type refrigerant compressor can reduce sliding loss and provide highly efficient refrigerant compression can do.

Further, even when contact occurs between the sliding portions and the single layer 228 is worn away and peeled off, the structure of molybdenum disulfide in the mixed layer 224 is a dense hexagonal crystal and the molecular size is about 6. Since it is as small as × 10 ⁻⁴ μm, it is cleaved with a low friction coefficient. Thus, even if metal contact occurs between the rolling piston 215 and the eccentric portion 207, between the main shaft portion 208 and the main bearing 213, and between the sub shaft portion 209 and the sub bearing 214, the sliding portion The friction coefficient is lowered, and the sliding loss is reduced. For this reason, according to the structure of Embodiment 2, a reliable refrigerant compressor can be provided.

  In addition, when the thickness of the mixed layer 224 is 0.1 μm to 2.0 μm and the maximum concentration of molybdenum disulfide in the mixed layer 224 is 5 wt% or more and 20 wt% or less, the self-lubricating property of molybdenum disulfide is stabilized. Further, the friction coefficient is further reduced. For this reason, by comprising as mentioned above, a highly reliable and highly efficient refrigerant compressor can be provided.

  In the second embodiment of the present invention, a mixed layer 224 in which molybdenum disulfide is dissolved is formed on the sliding surfaces of the eccentric portion 207, the main shaft portion 208, and the auxiliary shaft portion 209. Further, a single layer 228 of molybdenum disulfide was formed on the surface, but a mixed layer 224 and a single layer of molybdenum disulfide 228 were formed on the inner peripheral surface of the rolling piston 215, the main bearing 213, and the auxiliary bearing 214. Also good. Further, a mixed layer 224 and a single layer 228 of molybdenum disulfide are formed on both the eccentric portion 207 and the inner peripheral surface of the rolling piston 215, both the main shaft portion 208 and the main bearing 213, and both the sub shaft portion 209 and the sub bearing 214. May be. As described above, by forming the mixed layer 224 and the single layer of molybdenum disulfide 228 in the sliding portion, an excellent effect that a highly reliable and highly efficient refrigerant compressor can be provided is obtained. .

  Further, the rolling piston 215 and the vane 216, the main bearing 213 and the vane 216, the auxiliary bearing 214 and the vane 216, the main bearing 213 and the rolling piston 215, the auxiliary bearing 214 and the rolling piston 215, and the cylinder, which form sliding portions with each other, are formed. 212 and vane 216, cylinder 212 and rolling piston 215, and a mixed layer 224 in which molybdenum disulfide is dissolved are formed on the sliding surface of the oil supply pipe and the oil supply spring, and further disulfide is formed on the surface of this mixed layer 224. When the single layer 228 of molybdenum is formed, the friction coefficient at each sliding portion is reduced, and a highly reliable and highly efficient refrigerant compressor can be provided.

  As described above, the constant speed compressor has been described in the second embodiment of the present invention. While the speed of the refrigerant compressor is decreasing with the increase in the inverter, the problem of abnormal wear is further increased particularly in the ultra-low speed operation at a frequency lower than 20 Hz, so the effect of the present invention becomes more remarkable.

  As described above, in the refrigerant compressor of the present invention, a mixed layer in which molybdenum disulfide is dissolved is formed on the sliding surface of the sliding component, and a single layer of molybdenum disulfide is further formed on the surface of the mixed layer. Since the friction coefficient can be reduced and a highly reliable and highly efficient compressor can be provided, it can be widely applied to equipment using a refrigeration cycle.

It is sectional drawing of the refrigerant compressor in Embodiment 1 of this invention. It is the A section enlarged view in FIG. It is the B section enlarged view in FIG. It is a formation figure of molybdenum disulfide in Embodiment 1 of the present invention. It is the characteristic view which showed the relationship between the clearance of the piston / bore and refrigerating capacity in Embodiment 1 of this invention. It is a concentration distribution map of molybdenum disulfide in Embodiment 1 of the present invention. It is the characteristic view which showed the relationship between the molybdenum disulfide density | concentration and efficiency in Embodiment 1 of this invention. It is a connecting rod assembly figure which fixed the ball | bowl in Embodiment 1 of this invention by caulking. It is a block diagram of the household refrigerator in Embodiment 1 of this invention. It is sectional drawing of the expansion valve in Embodiment 1 of this invention. It is sectional drawing of the refrigerant compressor in Embodiment 2 of this invention. It is sectional drawing by the CD line in FIG. It is the E section enlarged view in FIG. It is sectional drawing of the conventional refrigerant compressor. It is sectional drawing of the mixed layer which made the conventional molybdenum disulfide solid solution.

Claims (10)

  A compression element having a sliding component made of a metal material is formed, and a mixed layer in which molybdenum disulfide is dissolved is formed on at least one sliding surface of the sliding component, and the surface of the mixed layer A refrigerant compressor in which a single layer of molybdenum disulfide is further formed.   The refrigerant compressor according to claim 1, wherein the maximum concentration of molybdenum disulfide in the mixed layer is 5 wt% or more.   The refrigerant compressor according to claim 1, wherein the mixed layer has a thickness of 0.1 μm to 2.0 μm.   The refrigerant compressor according to claim 1, wherein the purity of molybdenum disulfide forming the single layer of molybdenum disulfide is 98% or more.   The refrigerant compressor according to claim 1, wherein the thickness of the single layer of molybdenum disulfide is 0.1 μm to 2.0 μm. Stores oil in a sealed container and houses compression elements,
The compression element includes a crankshaft having a main shaft and an eccentric shaft, one of which is integrally formed with the crankshaft and the other of which is integrally formed with a bearing portion, and the main shaft rotatably supports the main shaft. A bearing block, a cylinder block that forms a cylinder, a piston that reciprocates in the cylinder, a piston pin that is disposed in parallel to the eccentric shaft and is fixed to the piston, and a connecting rod that connects the eccentric shaft and the piston. A reciprocating compression element with
The sliding component formed of a metal material is at least one of the crankshaft, the thrust portion, the cylinder block, the piston, the piston pin, and the connecting rod. The refrigerant compressor described in 1. Stores oil in a sealed container and houses compression elements,
The compression element includes a crankshaft having a main shaft and an eccentric shaft, one of which is integrally formed with the crankshaft and the other of which is integrally formed with a bearing portion, and the main shaft rotatably supports the main shaft. A bearing portion, a cylinder block that forms a cylinder, a piston that reciprocates in the cylinder, and a connecting rod that fixes a ball on the side to which the piston is connected;
The piston forms a reciprocating type compression element for caulking and fixing the ball;
The refrigerant according to any one of claims 1 to 5, wherein the sliding component formed of a metal material is at least one of the crankshaft, the thrust portion, the cylinder block, the piston, and the connecting rod. Compressor. Stores oil in a sealed container and houses compression elements,
The compression element includes a shaft having an eccentric portion, a cylinder forming a compression chamber concentric with the rotation center of the shaft, a rolling piston fitted in the eccentric portion and rolling in the compression chamber, and the rolling piston And a vane that partitions the compression chamber into a high pressure side and a low pressure side, and seals both side surfaces of the cylinder, and a main bearing on the electric element side that supports the shaft and a sub-element on the counter electric element side. Forming a rolling piston type compression element comprising a bearing, an oil supply spring fixed to one end of the shaft, and an oil supply pipe containing the oil supply spring and having one end opened in the oil;
The sliding part formed of a metal material is at least one of the shaft, the cylinder, the rolling piston, the vane, the main bearing, the auxiliary bearing, the oil supply spring, and the oil supply pipe. To 5. The refrigerant compressor according to any one of 5 to 5.   A cooling device comprising: the refrigerant compressor according to any one of claims 1 to 8, and at least one of a capillary tube and an expansion valve in an expander.   A refrigerator comprising the refrigerant compressor according to any one of claims 1 to 8, and a cooling device having at least one of a capillary tube and an expansion valve in an expander.

Images