JP2005113865A - Refrigerant compressor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a refrigerant compressor capable of using oil with low viscosity as refrigerator oil. <P>SOLUTION: By approximately uniformly providing fine recesses 123 on a sliding face of a piston 115, a bore 113 or the like serving as sliding components of the refrigerant compressor, oil can be held on the sliding face, and clearance between the sliding parts is minutely changed at the time of sliding. This generates dynamic pressure between the sliding parts, and makes it easy to hold an oil film. Accordingly, since generation of abnormal wear can be prevented, oil with low viscosity of which oil film on the sliding face is easily broken can be used. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a refrigerant compressor used for a refrigerator, an air conditioner and the like.

  Conventionally, as this kind of refrigerant compressor, development of a high-efficiency refrigerant compressor that reduces the use of fossil fuels from the viewpoint of protecting the global environment has been underway, and one of the sliding members that constitute the sliding portion is being developed. A nitriding-treated iron-based material is formed of a sliding material that is treated with manganese phosphate, and the other sliding member is formed of an anodized aluminum die cast (see, for example, Patent Document 1).

  FIG. 9 shows a cross-sectional view of a prior art hermetic electric refrigerant compressor described in Patent Document 1. In FIG. As shown in FIG. 9, 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 mechanism 6 driven thereby.

  Next, details of the compression mechanism 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 portion 9 formed eccentric to the main shaft portion 8, and 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 in the bore 12 is connected to the eccentric portion 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 valve plate 18 on the side opposite to 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 portion 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 movement of the eccentric portion 9 drives the piston 15 from the connecting rod 17 of the connecting means via the piston pin 16, whereby the piston 15 reciprocates in the bore 12, and the suction tube The refrigerant gas introduced into the sealed container 1 through 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, lubricates the sliding portion, and controls the seal between the piston 15 and the bore 12.
Japanese Patent Laid-Open No. 6-117371

  However, in the specification of the above conventional sliding material, if the viscosity of the oil 2 is lowered in order to reduce the viscous resistance, the solid contact between the sliding portions increases, and the sliding portion uses a manganese phosphate treatment with low hardness. Therefore, there is a problem that abnormal wear may occur.

  In addition, in the conventional specification of the sliding material, if the viscosity of the oil 2 is lowered, the retention of the oil 2 at the sliding portion is deteriorated, and the oil 2 flows out from the sliding portion when the refrigerant compressor is stopped. When restarted, the operation was started in a state where no oil film was generated on the sliding portion, and there was a problem that abnormal wear was likely to be caused.

  Further, when the viscosity of the oil 2 is lowered between the piston 15 and the bore 12, the compressed high-pressure refrigerant gas blows off the oil 2, the oil seal is cut and refrigerant gas leakage increases, and the gap between the piston 15 and the bore 12 increases. There has been a problem that volumetric efficiency decreases due to a significant increase in the leakage of refrigerant gas.

  The present invention solves the above-described conventional problems, and an object thereof is to provide a refrigerant compressor having high reliability and high efficiency while using low-viscosity oil.

  In order to solve the above-described conventional problems, a refrigerant compressor according to the present invention includes a compression mechanism that stores oil in a sealed container and compresses refrigerant gas, and is made of a metal material that constitutes the compression mechanism. A fine recess is formed almost uniformly on the sliding surface of the component, and the oil has a viscosity of less than VG10 and not less than VG5. As a result, oil accumulates in the recess on the surface of the sliding portion, and oil on the sliding surface. In addition, the gap between the sliding parts changes minutely during sliding, so that dynamic pressure is generated between the sliding parts and the oil film is easily held, and the frequency of solid contact is reduced. Sealability is improved.

  The refrigerant compressor of the present invention can provide a refrigerant compressor with high reliability and high efficiency while using low-viscosity oil.

  According to the first aspect of the present invention, a compression mechanism that stores oil in a sealed container and compresses a refrigerant gas is housed, and a fine depression is formed on a sliding surface of a sliding component made of a metal material that constitutes the compression mechanism. The oil is formed almost uniformly and the viscosity of the oil is less than VG10 and VG5 or more, so that the oil accumulates in the recess of the surface of the sliding part, and the oil can be held on the sliding surface and the gap between the sliding parts during sliding As a result of a slight change in pressure, dynamic pressure is generated between the sliding parts and the oil film is easily held, the frequency of solid contact is reduced, and the sealing part is improved in sealing performance. Can be high.

  In the second aspect of the invention, the surface area of the fine recess of the first aspect of the invention is a spherical surface, so that the cross-sectional area becomes larger than the shape of the polygonal cone having the same projected area on the sliding portion. Since the amount of oil that accumulates in the recess increases and the surface has a circular shape, the amount of change in the gap between the sliding parts that occurs during sliding is uniform, so the dynamic pressure generated during sliding Becomes uniform and efficiency can be increased.

In addition to the invention described in claim 1 or 2, the invention described in claim 3 has a fine recess size of 2 μm to 50 μm in diameter and 0.5 μm to 10 μm in depth. The reliability and efficiency can be increased while using low-viscosity oil even under the actual use conditions of the compressor. The invention according to claim 4 is a fine recess according to any one of claims 1 to 3. The surface of the steel is hardened by work hardening, etc. Even if metal contact occurs between the sliding parts, the high hardness will prevent abnormal wear and increase reliability while using low viscosity oil The invention according to claim 5 is the refrigerant of the invention according to any one of claims 1 to 4, wherein the refrigerant is one of R600a, R290, or a mixture thereof, and the oil is alkylbenzene, mineral oil, Tellurium, polyvinyl ether, polyalkylene glycol, or a mixture thereof, which is easy to dissolve in oil, and in combination with a refrigerant that tends to reduce the viscosity of the oil, holds the oil in the sliding part, By improving the wear resistance, abnormal wear of the sliding portion can be prevented, and reliability and efficiency can be increased while using low viscosity oil.

  According to a sixth aspect of the present invention, the compression mechanism according to any one of the first to fifth aspects is a reciprocating compression mechanism, and the sliding parts are a crankshaft, a bearing, a piston, a bore, and a piston pin. In the reciprocating compression mechanism, at least one of the sliding portions can obtain the effects of claims 1 to 5, and the reliability and efficiency can be increased while using low-viscosity oil. Can do.

  According to a seventh aspect of the present invention, the compression mechanism according to any one of the first to fifth aspects is a rotary compression mechanism, and the sliding parts are a shaft, a main bearing, a sub-bearing, and a rolling piston. Therefore, it is possible to obtain the effects of claims 1 to 5 at each sliding portion in a rotary compression mechanism, and to improve reliability and efficiency while using low-viscosity oil. Can do.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The present invention is not limited to the embodiments.

(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 of the same embodiment. FIG. 3 is a diagram showing the flow of oil during sliding in the same embodiment. FIG. 4 is a characteristic diagram of the friction coefficient between the sliding surface on which the fine depressions are formed substantially uniformly and the manganese phosphate layer. FIG. 5 is a characteristic diagram of the refrigerating capacity of the compressor when the fine depressions are formed almost uniformly on the sliding surface and when the manganese phosphate layer is applied. FIG. 6 is a characteristic diagram of the efficiency in the compressor when the fine depressions are formed almost uniformly on the sliding surface and when the manganese phosphate layer is applied.

  1, 2, and 3, the sealed container 101 is filled with a refrigerant gas 102 made of R600a, and an oil 103 made of mineral oil and having a viscosity of less than VG10 and having a viscosity of VG5 or more is stored at the bottom, and the stator 104, An electric element 106 including a rotor 105 and a reciprocating compression mechanism 107 driven by the electric element 106 are housed.

  Next, details of the compression mechanism 107 will be described below.

  The crankshaft 108 is composed of a main shaft portion 109 in which the rotor 105 is press-fitted and fixed, and an eccentric portion 110 formed eccentric to the main shaft portion 109, and an oil supply pump 111 communicating with the oil 103 is provided at the lower end. The cylinder block 112 made of cast iron forms a substantially cylindrical bore 113 and a bearing portion 114 that supports the main shaft portion 109.

  The piston 115 loosely fitted in the bore 113 is made of an iron-based material, forms a compression chamber 116 together with the bore 113, and is connected to the eccentric portion 110 via a piston pin 117 by a connecting rod 118 as connecting means. The end surface of the bore 113 is sealed with a valve plate 119.

  The head 120 forms a high pressure chamber and is fixed to the valve plate 119 on the side opposite to the bore 113. The suction tube 121 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 122 is sandwiched between the valve plate 119 and the head 120.

  The main shaft portion 109 and the bearing portion 114, the piston 115 and the bore 113, the piston pin 117 and the connecting rod 118, and the eccentric portion 110 and the connecting rod 118 form a sliding portion.

  On the surface of the sliding portion, a fine recess 123 having a diameter of 2 μm to 50 μm and a depth of 0.5 μm to 10 μm is formed substantially uniformly on the surface of the iron-based material as a base material.

  Examples of a method for forming such a fine recess 123 include surface etching and press molding. In the present embodiment, the fine recess 123 is formed by a method in which a hard sphere such as a steel ball or a ceramic sphere collides at a certain speed or higher.

  The operation of the refrigerant compressor configured as described above will be described below.

  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 rotor 105 rotates the crankshaft 108, and the eccentric movement of the eccentric portion 110 drives the piston 115 from the connecting rod 118 of the connecting means via the piston pin 117, whereby the piston 115 reciprocates in the bore 113, and the suction tube The refrigerant gas 102 introduced into the sealed container 101 through 121 is sucked from the suction muffler 122 and continuously compressed in the compression chamber 116.

  As the crankshaft 108 rotates, the oil 103 is supplied to each sliding portion from the oil supply pump 111, lubricates the sliding portion, and controls the seal between the piston 115 and the bore 113.

  Here, the operation of each sliding portion formed between the sliding members of the main shaft portion 109 and the bearing portion 114, the piston 115 and the bore 113, the piston pin 117 and the connecting rod 118, and the eccentric portion 110 and the connecting rod 118 will be described.

  Since the viscosity of the oil 103 is as low as less than VG10 or more than VG5 between the sliding parts, the sliding parts are likely to be brought into solid contact with each other. Further, since the refrigerant is R600a, the oil 103 easily dissolves in the oil 103 made of mineral oil. Since the viscosity of the oil 103 is reduced, solid contact is more likely to occur.

  However, as shown in FIG. 3, the oil flow 103a that generates an oil film generated when the sliding portion slides easily forms a vortex flow in the spherical fine recess 123, and as a result, hydraulic pressure is generated. This prevents solid contact and improves wear resistance.

  In addition, in the present embodiment, since the fine recess 123 is formed by a method in which a hard ball such as a steel ball or a ceramic ball is collided at a certain speed or more, the surface hardness increases due to work hardening or the like. Even when solid contact occurs, abnormal wear is prevented and wear resistance is improved. In particular, when the sliding part is the piston 115 and the bore 113, and the piston pin 117 and the connecting rod 118, the mutual sliding speed becomes 0 m / s twice per compression process, so the hydraulic pressure becomes zero and solid contact is likely to occur. Therefore, this technique is extremely effective.

  Here, with reference to FIG. 4, the friction coefficient when the oil viscosity is changed between the case where the fine recesses 123 are formed almost uniformly on the sliding surface according to the present embodiment and the case where the manganese phosphate layer is applied will be described. .

  FIG. 4 shows a disk having a diameter of 2 μm to 15 μm and a depth of 0.5 μm to 1 μm using ester oil of VG4 to VG22 and ethanol equivalent to VG1 under an atmospheric pressure of 0.4 MPa of HFC134a refrigerant. And a fine dent 123 having a diameter of 40 μm to 50 μm and a depth of 7 μm to 10 μm, and a fine dent 123 having a diameter of 60 μm to 70 μm and a depth of 15 μm to 20 μm. Is a result of a wear test carried out under the condition that the sliding speed is rotated at 1.0 m / s and the opposing material formed in a ring shape is pressed at a surface pressure of 0.5 MPa.

  (Table 1) is the numerical data of FIG.

  From this result, in the case where the manganese phosphate layer and the fine dent 123 having a diameter of 60 μm to 70 μm and a depth of 15 μm to 20 μm are formed almost uniformly, the friction coefficient increases when the oil viscosity is less than VG10. When the fine dent 123 having a diameter of 40 μm to 50 μm and a depth of 7 μm to 10 μm is formed almost uniformly, and a fine dent 123 having a diameter of 2 μm to 15 μm and a depth of 0.5 μm to 1 μm When the oil viscosity is reduced to VG8, the friction coefficient is not increased even when the oil viscosity is decreased to VG8. Even when the oil viscosity is decreased to VG4, the friction coefficient is only slightly increased. It can also be seen that the coefficient of friction is lower than that of the manganese phosphate treatment.

  This is because the microscopic recesses 123 having a diameter of 40 μm to 50 μm and a depth of 7 μm to 10 μm or a diameter of 2 μm to 15 μm and a depth of 0.5 μm to 1 μm are provided almost uniformly on the sliding portion. The gap is constant when the dynamic pressure between the sliding parts is made uniform, and the volume fluctuation in the fine depression is reduced, and the gap that occurs when oil containing refrigerant is supplied to the fine depression. The pressure drop in the oil is small, the foaming phenomenon in the oil is suppressed and the oil film is prevented from breaking, and the oil pressure of the formed oil film is increased, so the load on the solid contact portion is reduced and the friction coefficient is lowered. This is probably due to the fact that

  Furthermore, changes in the refrigerating capacity of the reciprocating refrigerant compressor and the coefficient of performance (COP) of the refrigerant compressor were measured using the oil viscosity as a parameter.

  5 and FIG. 6, a fine recess 123 having a diameter of 2 μm to 50 μm and a depth of 0.5 μm to 10 μm is uniformly provided on the sliding portion of the piston 115, and R600a refrigerant, VG5 and VG10 mineral oil are used, The refrigerant compressor's refrigeration capacity and coefficient of performance (COP) were measured under the conditions of condensation temperature / evaporation temperature: 54.4 ° C./−23.3° C., intake gas, temperature before expansion valve: 32.2 ° C. The results are compared with the manganese phosphate treatment.

  (Table 2) is the numerical data of FIG. 5, and (Table 3) is the numerical data of FIG.

  From these results, in FIG. 5, when the manganese phosphate treatment lowered the viscosity of the oil 103 from VG10 to VG5, compared with the fact that the refrigerating capacity was greatly reduced to about 11 W, the fine depression 123 was provided. Then, it can be seen that the decrease in the refrigerating capacity is about 1 W, which is very small.

  This is because when the piston 115 reciprocates in the bore 113 and compresses the refrigerant gas 102, the viscosity of the oil 103 is very low, so that the sealing performance is lowered, and the refrigerant gas 102 compressed in the compression chamber 116 is reduced. Despite leakage from the gap between the piston 115 and the bore 113 into the sealed container 101 and the refrigeration capacity being easily reduced, a wedge-shaped oil film is formed by the fine depression 123 provided in the piston 115, and the gap between the piston 115 and the bore 113. It can be presumed that the amount of refrigerant gas leaking from the fuel is reduced.

  That is, when the leaked refrigerant gas 102 in the gap between the piston 115 and the bore 113 reaches the fine depression 123, the volume of the gap between the piston 115 and the bore 113 increases in the fine depression 123, so that the same action as the labyrinth seal occurs. It is considered that the flow rate of the leaked refrigerant gas 102 is rapidly reduced, so that the leakage amount of the refrigerant gas 102 is reduced, and as a result, the reduction in the refrigerating capacity of the refrigerant compressor can be suppressed very little.

  Similarly, in FIG. 6, the coefficient of performance (COP) indicating the efficiency of the compressor is higher in the case where the fine depression is provided than in the case of the manganese phosphate treatment. As shown in FIG. In addition to maintaining the volumetric efficiency due to the fact that the reduction in the refrigeration capacity of the compressor can be suppressed to a very low level, as shown in FIG. 4, the increase in the coefficient of friction at the sliding portion is extremely higher than that of the manganese phosphate treatment. It is considered that the reduction of the input due to the small amount and the reduction of the viscous resistance accompanying the decrease of the oil viscosity from VG10 to VG5 greatly contributed to the reduction of the input of the refrigerant compressor.

  As described above, in the present embodiment, the constant speed compressor has been described. However, as the speed of the refrigerant compressor is reduced along with the inverter, the oil 103 is further reduced particularly in an ultra-low speed operation of less than 20 Hz. Needless to say, problems in viscosity increase become significant and the effects of the present invention become remarkable.

  Also, this time, the combination of R600a and mineral oil has been described as an example, but when the refrigerant used is R290, which is the same hydrocarbon refrigerant, the oil 103 used is also alkylbenzene, ester, polyvinyl ether, poly Even when the oil 103 such as alkylene glycol is used, a similar effect can be obtained because the refrigerant dissolves in the oil 103 and further reduces the viscosity.

  In the present embodiment, the fine recesses 123 having a diameter of 2 μm to 50 μm and a depth of 0.5 μm to 10 μm are provided almost uniformly on both of the sliding parts. The same effect can be obtained. Further, it is needless to say that the same action and effect can be obtained even when the sliding portion material is made of other materials such as aluminum in view of the oil film formation principle.

(Embodiment 2)
FIG. 7 is a cross-sectional view of the refrigerant compressor in the second embodiment of the present invention. FIG. 8 is an enlarged view of part B of the same embodiment.

  7 and 8, the hermetic container 201 accommodates an electric element 204 including a stator 202 and a rotor 203, and a rolling piston type compression mechanism 205 driven by the electric element 204. A refrigerant gas (not shown) composed of an oil 206 having a viscosity of R and a R600a is enclosed.

  The compression mechanism 205 seals the shaft 210 having the eccentric portion 207, the main shaft portion 208, and the sub shaft portion 209, the cylinder 212 forming the compression chamber 211, and both ends of the cylinder 212, and the main shaft portion 208 and the sub shaft portion, respectively. 209, the main bearing 213 and the sub-bearing 214, the rolling piston 215 that is loosely fitted in the eccentric part 207 and rolls in the compression chamber 211, and the pressure is inserted into the rolling piston 215. And a plate-like vane 216 which is divided on the side, and a rotor 203 is fixed to the main shaft portion 208. 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 form a sliding portion.

  The oil pump 217 fixed to the sub-bearing 214 has one end communicating with the oil 206 and the other end communicating with each sliding portion.

  And the surface of each said sliding part has formed the micro indentation 218 with a diameter of 2 micrometers-50 micrometers and a depth of 0.5 micrometer-10 micrometers on the surface of the iron-type material which is a base material substantially uniformly.

  The operation of the refrigerant compressor configured as described above will be described below.

  Electric power supplied from a commercial power source (not shown) is supplied to the electric element 204 to rotate the rotor 203, whereby the shaft 210 rotates, and the rolling piston 215 loosely fitted in the eccentric part 207 moves inside the compression chamber 211. Rolling and the vane 216 partitions the compression chamber 211 into a high pressure side and a low pressure side, so that the refrigerant gas is continuously compressed in the compression chamber 211.

  Further, as the shaft 210 rotates, the oil pump 217 continuously supplies the oil 206 to the sliding portions. Then, by forming the fine recesses 218 substantially uniformly, the oil 206 is drawn into the gaps between the sliding portions, and a wedge-shaped oil film is formed.

Here, 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 and the main bearing 213. The relative speed between the auxiliary shaft portion 209 and the auxiliary bearing 214 becomes smaller. This means that the Sommerfeld number S (Equation 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. This is a disadvantageous condition in which solid contact is likely to occur.
S = μ × N / P × (R / C) ² (Equation 1)
However, a fine indentation having a diameter of 2 μm to 50 μm and a depth of 0.5 μm to 10 μm by a method in which a hard ball such as a steel ball or a ceramic ball collides with the sliding part surface of the eccentric part 207 at a certain speed or more. By providing 218 substantially uniformly, even if solid contact occurs, the surface hardness of the sliding portion increases due to work hardening or the like, thereby improving wear resistance and preventing abnormal wear.

  Further, in the rolling piston type refrigerant compressor, since the inside of the sealed container 201 generally has a condensation pressure, the internal pressure is high, and the refrigerant of the oil 206 is likely to be melted. This is to reduce the viscosity of the oil 206, 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, since the fine depression 218 is fine, even if the oil 206 into which the refrigerant is melted is supplied into the fine depression 218, the volume change in the depression is small and the decrease in the atmospheric pressure is reduced, and the pressure of the compressed refrigerant gas is reduced. Since the high pressure is maintained, a decrease in the amount of the refrigerant that can be dissolved in the oil 206 is suppressed, the foaming phenomenon of the refrigerant in the oil 206 is reduced, and the oil film formed on the sliding portion by the foaming breaks. The occurrence of solid contact is reduced, and an increase in the friction coefficient can be prevented.

  Furthermore, when the sliding speed is changed by an inverter or the like, it can be easily estimated that a great effect can be obtained particularly in a low-speed operation of less than 20 Hz.

  Moreover, this time, the combination of R600a and mineral oil has been described as an example, but when the refrigerant used is R290, which is the same hydrocarbon refrigerant, the oil 206 used is also an alkylbenzene, ester, polyvinyl ether, poly Even when the oil 206 such as alkylene glycol is used, a similar effect can be obtained because the refrigerant dissolves in the oil 206 and further reduces the viscosity.

  In this embodiment, fine recesses 218 each having a diameter of 2 μm to 50 μm and a depth of 0.5 μm to 10 μm are provided almost uniformly on both of the iron-based sliding parts. Needless to say, the same action and effect can be obtained by considering the oil film formation principle as other materials.

  As described above, the refrigerant compressor according to the present invention can provide a compressor having high reliability and high efficiency, and thus can be widely applied to devices using a refrigeration cycle.

Sectional drawing of the refrigerant compressor in Embodiment 1 of this invention. Part A enlarged view in FIG. The figure which showed the flow of the oil at the time of sliding in Embodiment 1 of this invention Friction coefficient characteristic diagram in Embodiment 1 of the present invention Characteristics diagram of refrigeration capacity in Embodiment 1 of the present invention Efficiency characteristic diagram according to Embodiment 1 of the present invention Sectional drawing of the refrigerant compressor in Embodiment 2 of this invention. Part B enlarged view in FIG. Sectional view of a conventional refrigerant compressor

Explanation of symbols

101, 201 Airtight container 102 Refrigerant gas 103, 206 Oil 107, 205 Compression mechanism 108 Crankshaft 113 Bore 114 Bearing 115 Piston 116 Piston pin 123, 218 Fine recess 210 Shaft 213 Main bearing 214 Sub bearing 215 Rolling piston

Claims (7)

A compression mechanism that stores oil in a sealed container and compresses a refrigerant gas is accommodated, and a fine recess is formed almost uniformly on a sliding surface of a sliding part of a metal material that constitutes the compression mechanism. A refrigerant compressor having a viscosity of less than VG10 and VG5 or more. The refrigerant compressor according to claim 1, wherein the surface shape of the fine recess is a spherical surface. The refrigerant compressor according to claim 1 or 2, wherein the fine recess has a diameter of 2 µm to 50 µm and a depth of 0.5 µm to 10 µm. The refrigerant compressor according to any one of claims 1 to 3, wherein the surface of the fine depression is increased in hardness by work hardening or the like. The refrigerant is any one of R600a and R290, or a mixture thereof, and the oil is any one of alkylbenzene, mineral oil, ester, polyvinyl ether, polyalkylene glycol, or a mixture thereof. The refrigerant compressor described in 1. The refrigerant compressor according to any one of claims 1 to 5, wherein the compression mechanism is a reciprocating compression mechanism, and the sliding component is at least one of a crankshaft, a bearing, a piston, a bore, and a piston pin. The refrigerant compressor according to any one of claims 1 to 5, wherein the compression mechanism is a rotary compression mechanism, and the sliding component is at least one of a shaft, a main bearing, a sub bearing, and a rolling piston.

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