JP2010249391A - Sliding member, hermetic compressor, and refrigeration cycle apparatus - Google Patents

Abstract

A highly reliable hermetic compressor that can be used under high load conditions is provided.
The crankshaft is made of austenite and is cast iron containing vanadium spherical carbide in the structure, thereby dispersing the high-hardness spherical carbide in the structure and increasing the hardness of the sliding member. Even when metal contact occurs under a high load due to increased toughness, it does not generate peeling due to frictional force, and has the effect of improving wear resistance at the sliding part, so it is a highly reliable sealed type A compressor can be provided.
[Selection] Figure 1

Description

  The present invention relates to a hermetic compressor mainly used in an electric refrigerator-freezer for home use.

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

  Conventionally, this type of sliding member and hermetic compressor have formed a phosphate coating on the sliding surfaces of pistons, crankshafts, etc., thereby eliminating the irregularities on the machined surface. There is one with good initial familiarity (see, for example, Patent Document 1).

  The conventional sliding member and hermetic compressor will be described below with reference to the drawings.

  FIG. 2 shows a cross-sectional view of a conventional hermetic compressor described in Patent Document 1. In FIG.

  In FIG. 2, 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 by the electric element 5.

  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, and an oil supply pump 10 is provided. 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 that 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 (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. In the combination of iron-based materials among the sliding members constituting the structure, an insoluble phosphate film (not shown) made of a porous crystal is formed on the surface of one of the sliding parts. Yes.

  The operation of the hermetic 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 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 shaft 9 drives the piston 15 from the connecting rod 17 of the connecting means through the piston pin 16, whereby the piston 15 reciprocates in the bore 12, and the suction tube The refrigerant 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.

Here, the main shaft portion 8 and the bearing portion 14 of the crankshaft 7 are rotating, and naturally when the hermetic compressor is stopped, the speed is 0 m / s. Exercise begins. However, by forming the phosphate film on the main shaft portion 8 of the crankshaft 7, abnormal wear due to metal contact at start-up can be prevented due to the initial familiarity of the phosphate film.
Japanese Patent Application Laid-Open No. 7-238885

  However, in the above-described conventional configuration, the phosphate coating is designed to reduce the viscosity of the oil 2 and increase the clearance between the sliding portions with the recent increase in efficiency of hermetic compressors. The salt film may be worn or worn away, making it difficult to maintain the conforming effect and lowering the wear resistance.

  In particular, in a hermetic compressor, the load acting on the main shaft portion 8 of the crankshaft 7 greatly fluctuates while the crankshaft 7 makes one revolution, and the refrigerant dissolved in the oil 2 foams due to this load fluctuation. Metal contact between the main shaft portion 8 of the crankshaft 7 and the bearing portion 14 increases, the phosphate film formed on the main shaft portion 8 of the crankshaft 7 wears, and the friction coefficient increases, so that heat generation at the sliding portion increases. There was a possibility that abnormal wear such as adhesion would occur.

  Moreover, since the same phenomenon is caused between the piston 15 and the bore 12, there is a similar problem.

  The present invention solves the above-mentioned conventional problems, and provides a sliding member with improved wear resistance, and an object of the present invention is to provide a highly reliable hermetic compressor with high reliability.

  In order to solve the above-mentioned conventional problems, the sliding member of the present invention is formed of cast iron containing spherical carbide in the structure, thereby improving the mechanical strength of the cast iron and thereby improving the wear resistance. It has the effect of improving.

  Since the sliding member and the hermetic compressor of the present invention have improved wear resistance due to an increase in mechanical strength, a highly reliable sliding member and a highly reliable hermetic compressor are provided. Can do.

  The invention described in claim 1 is characterized in that it is formed of cast iron containing spherical carbide in the structure, which increases mechanical strength and improves wear resistance at the sliding portion. By having the action, a highly reliable sliding member can be provided.

The invention according to claim 2 is the invention according to claim 1, wherein the spherical carbide contained in the sliding member is vanadium carbide, whereby the high-hardness spherical carbide is dispersed and slid in the tissue. By increasing the hardness of the member and increasing the toughness, there is no peeling due to frictional force even when metal contact occurs under high load, and it has the effect of improving the wear resistance at the sliding part In addition to the effects of the invention described in claim 1, a highly reliable sliding member can be provided.

  The invention according to claim 3 is the invention according to claim 1 or 2, wherein the base of the sliding member is austenite, whereby the base structure becomes a face-centered cubic lattice structure and wear resistance of the base. In addition to the effect of the invention according to claim 1, further providing a highly reliable sliding member by improving the wear resistance and further improving the wear resistance at the sliding portion. Can do.

  According to a fourth aspect of the present invention, lubricating oil is stored in an airtight container, and an electric element and a compression element that drives the electric element and compresses a refrigerant are accommodated, and the compression element constitutes an iron-based metal material. The sliding member according to any one of claims 1 to 3 is used for at least one sliding member made of the above, and the sliding portion is made of cast iron including a spherical carbide in the structure. The mechanical strength of the portion is increased and the sliding properties such as wear resistance are improved, whereby a highly reliable hermetic compressor can be provided.

  The invention according to claim 5 is the invention according to claim 4, wherein the refrigerant is any one of R600a and R290, or a mixture thereof, and the lubricating oil is alkylbenzene, mineral oil, ester, polyvinyl ether, polyalkylene. In addition to any one of glycols or a mixture thereof, the lubricating oil has a viscosity grade of less than VG10 and VG2 or more, and has an effect of improving wear resistance by increasing mechanical strength and toughness. Thereby, in addition to the effect of the invention of the fourth aspect, a highly reliable hermetic compressor can be provided.

  The invention according to claim 6 is the invention according to claim 4, wherein the refrigerant is an HFC refrigerant, and the lubricating oil is any one of alkylbenzene, mineral oil, ester, polyvinyl ether, polyalkylene glycol, or these The lubricant according to claim 4, wherein the lubricating oil has a viscosity grade less than VG10 and VG2 or more, and has an effect of improving wear resistance by increasing mechanical strength and toughness. In addition to the effects of the invention, a highly reliable hermetic compressor can be provided.

  The invention according to claim 7 is the invention according to any one of claims 4 to 6, wherein the compression element is composed of a reciprocating compression mechanism, and has high mechanical strength and toughness. Thus, by preventing the peeling at the sliding portion, it has the effect that it can cope with the deterioration of the lubrication state due to the sliding condition such as the load changing according to the operating load. In addition to the effect of the invention described in the above item 1, a highly reliable hermetic compressor can be provided.

  The invention according to claim 8 includes the hermetic compressor according to any one of claims 4 to 7, wherein an HFC-based refrigerant or an HC refrigerant is used as a refrigerant, and the concentration of sulfur dioxide contained in the refrigerant The sulfur dioxide reacts with moisture contained in the refrigeration cycle to form sulfurous acid, corroding the reaction layer and the base material, thereby promoting wear and preventing clogging of the cycle due to the wear powder. Thus, a highly reliable refrigeration cycle apparatus can be provided.

(Embodiment 1)
1 is a cross-sectional view of a hermetic compressor according to a first embodiment of the present invention.

  In FIG. 1, an airtight container 101 is filled with a refrigerant 102 made of R600a, and an oil 103 which is a lubricating oil of less than VG2 and more than VG2 is stored at the bottom, and an electric element made up of a stator 104 and a rotor 105. 106 and a reciprocating compression element 107 driven thereby are accommodated.

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

  The crankshaft 108, which is made of austenite and is cast iron containing vanadium spherical carbide in the structure, includes a main shaft 109 in which a 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 103 is provided. A cylinder block 112 made of cast iron forms a substantially cylindrical bore 113 and a bearing portion 114 that supports the 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 constituted 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 connected to the eccentric shaft 138 as a connecting means via a piston pin 137. 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 side opposite to the bore 113 of the valve plate 139. 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 102 into the sealed container 101. The suction muffler 142 is sandwiched between the valve plate 139 and the head 140.

  The operation of the hermetic compressor 153 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 shaft 110 drives the piston 132 from the connecting rod 138 of the connecting means through the piston pin 137, whereby the piston 132 reciprocates in the bore 113, and the suction tube The refrigerant 102 introduced into the sealed container 101 through (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, lubricates the sliding portion, and controls the seal between the piston 132 and the bore 113.

  At this time, the main shaft 109 of the crankshaft 108 and the eccentric shaft 110 formed eccentrically with respect to the main shaft 109 due to the gas pressure of the compressed refrigerant 102 and the bearing portion 114 of the cylinder block 112 and the connecting rod 138 vary with load variation. A load is applied.

  As the load fluctuates, the refrigerant 102 dissolved in the oil 103 repeatedly foams, and the clearance becomes smaller as the efficiency increases, so that the frequency of metal contact increases.

Furthermore, since the oil viscosity is less than VG10 and VG2 or more, the amount of oil 103 held between the sliding portions is reduced when the hermetic compressor 153 is stopped, and the frequency of metal contact immediately after startup is increased.

  In the present embodiment, the crankshaft 108 has a face-centered cubic lattice structure of vanadium spherical carbide having a hardness of 2300 HV, and carbon penetrates into the face-centered cubic lattice. Compared with the body-centered cubic lattice structure, which is a general iron crystal structure, because the vanadium spherical carbide has a high hardness and the base has a face-centered cubic lattice structure. Thus, high toughness can be obtained because of the high mechanical properties.

  Therefore, even if metal contact frequently occurs between the eccentric shaft 110 formed eccentric to the main shaft 109 and the bearing portion 114 of the cylinder block 112 and the connecting rod 138, wear such as peeling is caused. Thus, abnormal wear does not occur and a highly reliable hermetic compressor 153 can be provided.

  Moreover, sulfur dioxide (SO2) is contained in the atmosphere today due to emissions of automobile exhaust gas, volcanic gas, and the like. This sulfur dioxide (SO2) reacts with water to become sulfurous acid (H2SO3).

  Therefore, in a refrigeration cycle having a condenser (not shown), a dryer (not shown), a capillary (not shown), an evaporator (not shown), etc., vacuuming or the like when sealing the refrigerant 102 is not required. If sufficient, sulfur dioxide (SO2) remains in the refrigeration cycle and reacts with moisture contained in the refrigeration cycle to become sulfurous acid (H2SO3), and this acidic substance, sulfurous acid (H2SO3) is the base material of the sliding part. There is a possibility of oxidative degradation of ferrous materials.

  However, since vanadium spherical carbide that is chemically stable and does not cause a corrosion reaction is uniformly dispersed in the dough, the oxidation reaction rate is reduced even in a sulfurous acid (H2SO3) atmosphere, and the deterioration of the iron-based material can be prevented. I understood. Therefore, if the concentration of sulfur dioxide (SO2) contained in the refrigeration cycle is up to 50 ppm, oxidative deterioration can be prevented, and a highly reliable refrigeration cycle apparatus can be provided.

  Therefore, removing sulfur dioxide (SO2) in the refrigeration cycle reduces productivity and increases costs, but by allowing the concentration of sulfur dioxide (SO2) in the refrigeration cycle to 50 ppm, production Thus, the cost can be reduced.

  As described above, in the first embodiment of the present invention, the sealed compressor 153 having a constant speed has been described. However, as the speed of the hermetic compressor 153 decreases as the inverter is changed, an ultra-low speed operation particularly lower than 20 Hz is performed. In this case, it becomes more difficult to establish fluid lubrication, and metal contact is likely to occur, so that the effect of the present invention becomes more remarkable.

  Furthermore, in Embodiment 1 of the present invention, the refrigerant is described as R600a, but the refrigerant 102 is R290 or a mixture of R600a and R290, and the oil 103 is any one of alkylbenzene, mineral oil, ester, polyvinyl ether, and polyalkylene glycol. The same effect can be obtained when the refrigerant 102 is an HFC refrigerant and the oil 103 is any one of alkylbenzene, mineral oil, ester, polyvinyl ether, polyalkylene glycol, or a mixture thereof.

In the first embodiment of the present invention, the crankshaft 108 is austenite based on the crankshaft and is described in detail as an example of cast iron containing vanadium spherical carbide in the structure. Even in the bearing portion 114 of the block 112 and the sliding portion of the connecting rod 138, a considerable effect can be obtained. Furthermore, considerable effects can be obtained also in other sliding parts.

  Moreover, by providing the above-described hermetic compressor in a refrigeration cycle apparatus, a refrigeration cycle apparatus with high productivity and high reliability can be provided.

  As described above, in the sliding member and the hermetic compressor according to the present invention, the base of at least one sliding member of the sliding component made of a metal material is austenite, and the cast iron containing vanadium spherical carbide in the structure. As a result, it is possible to improve wear resistance by increasing the mechanical strength and to provide a highly reliable hermetic compressor, so it can be widely applied to equipment using a refrigeration cycle. it can.

Sectional drawing of the hermetic compressor in Embodiment 1 of this invention Cross section of a conventional hermetic compressor

101 Airtight container 102 Refrigerant 103 Oil (lubricating oil)
106 electric element 107 compression element 153 hermetic compressor

Claims (8)

A sliding member formed of cast iron containing a spherical carbide in the structure. The sliding member according to claim 1, wherein the spherical carbide contained in the sliding member is vanadium carbide. The sliding member according to claim 1 or 2, wherein the base of the sliding member is austenite. The lubricating oil is stored in a sealed container, and the electric element and the compression element that drives the electric element and compresses the refrigerant are accommodated. At least one sliding member that constitutes the compression element and is made of an iron-based metal material. A hermetic compressor using the sliding member according to any one of claims 1 to 3. The refrigerant is any one of R600a and R290, or a mixture thereof, and the lubricating oil is any one of alkylbenzene, mineral oil, ester, polyvinyl ether, polyalkylene glycol, or a mixture thereof, and the lubricating oil is The hermetic compressor according to claim 4, wherein the viscosity grade is less than VG10 and VG2 or more. The refrigerant is an HFC-based refrigerant, and the lubricating oil is one of alkylbenzene, mineral oil, ester, polyvinyl ether, polyalkylene glycol, or a mixture thereof, and the lubricating oil has a viscosity grade of less than VG10 and VG2 or more. The hermetic compressor according to claim 4. The hermetic compressor according to any one of claims 4 to 6, wherein the compression element includes a reciprocating compression mechanism. A refrigeration cycle apparatus comprising the hermetic compressor according to any one of claims 4 to 7, wherein an HFC refrigerant or HC refrigerant is used as a refrigerant, and a concentration of sulfur dioxide contained in the refrigerant is 50 ppm or less.