Hermetic refrigeration compressor and refrigerator-freezer appliance using the same

Abstract

The sealed refrigeration compressor comprises a sealed container 101 in which a lubricating oil 103 having a kinematic viscosity in the range of 1 mm 2 to 10 mm 2 at 40°C is stored, the sealed container 101 housing an electrical element 106 and a compression element 107 driven by the electrical element 106 and configured to compress a refrigerant. The lubricating oil 103 has a surface tension in the range of 23 mN / m to 45 mN / m.

Description

Technical Field

[0001] The present invention relates to a hermetically sealed refrigeration compressor used in, for example, refrigerators or air conditioners, and also to a refrigeration and freezing apparatus using the hermetically sealed refrigeration compressor. Background Technology

[0002] In recent years, from the perspective of protecting the global environment, highly efficient sealed refrigeration compressors that reduce the use of fossil fuels have been developed. For example, to achieve high efficiency, it has been proposed to form various films on the sliding surfaces of sliding components (included in the refrigeration compressor) and to use lubricating oils with low viscosity.

[0003] A hermetically sealed refrigeration compressor includes a sealed container in which lubricating oil is stored. The sealed container also houses electrical components and compression components. The compression components include sliding members (e.g., a crankshaft, piston, and connecting rod as a coupling). The crankshaft's main shaft and main bearings, piston and bore, piston pin and connecting rod, and crankshaft's eccentric shaft and connecting rod, etc., form sliding portions with each other.

[0004] For example, Patent Document 1 discloses a reciprocating compressor (sealed refrigeration compressor) using a low-viscosity lubricating oil. The reciprocating compressor is configured such that in the sliding components, both the piston and connecting rod are made of sintered iron material and are steam-treated. The steam layer is then removed from the piston surface by cutting, while the connecting rod is nitrided after steam treatment. In Patent Document 1, the lubricating oil used in this reciprocating compressor has a viscosity of 3 mm at 40°C. 2 / S to 10mm 2 Kinematic viscosity in the range of / S.

[0005] If the lubricating oil has low viscosity, it is not easy to form an oil film. In this regard, in the hermetically sealed refrigeration compressor disclosed in Patent Document 1, the surface of the sliding member forming the sliding part is specially treated so that even if a low-viscosity lubricating oil is used, wear or seizing of the piston and connecting rod will be prevented. Reference List Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No.: 2011-021530 Summary of the Invention Technical issues

[0007] As mentioned above, if the lubricating oil has a low viscosity, it is not easy to form an oil film. Therefore, in this case, the oil film may partially break down, and the sliding surfaces will come into contact with each other more frequently. If the sliding surfaces come into contact with each other more frequently, there is a concern that at least one of the sliding surfaces may wear, leading to an increase in the coefficient of friction, and the heat generated by the sliding parts may increase, resulting in abnormal wear, such as adhesion. In other words, if the oil film formed by the lubricating oil is prone to breakage, it will reduce the wear resistance of the sliding parts.

[0008] The reciprocating compressor (sealed refrigeration compressor) disclosed in Patent Document 1 uses a low-viscosity lubricating oil with a kinematic viscosity of 3 mm at 40°C. 2 / S to 10mm 2 Within the range of / S. However, the wear resistance to be improved in Patent Document 1 is only the wear resistance of the piston and connecting rod. Therefore, the technology in Patent Document 1 cannot adequately address the reduction in wear resistance of sliding parts that are different from the piston and connecting rod.

[0009] This invention was made to solve the above-mentioned problems. The object of this invention is to provide a sealed refrigeration compressor that can effectively suppress the reduction of wear resistance in sliding parts even when using lubricating oil with low viscosity. Solution to the problem

[0010] To address the aforementioned problems, the hermetically sealed refrigeration compressor according to the present invention includes a hermetically sealed container in which a substance with a kinematic viscosity of 1 mm at 40°C is stored. 2 / S to 10mm 2 The lubricating oil is within the range of / S, and the sealed container houses electrical components and a compression element, which is driven by the electrical components and configured to compress the refrigerant. The lubricating oil has a surface tension in the range of 23 mN / m to 45 mN / m.

[0011] According to the above structure, the lubricating oil stored in the sealed container has low viscosity and high surface tension. Therefore, at the sliding part included in the compression element, the oil film formed between the sliding surfaces can be maintained as a thin film. Therefore, even if the oil film forms a thin film, its rupture can be effectively suppressed. Thus, while improving the efficiency of the sealed refrigeration compressor, it is advantageous to suppress the reduction of wear resistance at the sliding part.

[0012] The refrigeration and freezing apparatus according to the present invention includes a refrigerant circuit comprising: a hermetically sealed refrigeration compressor as described above; a radiator; a pressure reducer; and a heat absorber. In the refrigerant circuit, the hermetically sealed refrigeration compressor, the radiator, the pressure reducer, and the heat absorber are connected in a loop via pipes.

[0013] According to the above structure, since the hermetic refrigeration compressor uses a lubricating oil with low viscosity and high surface tension, good wear resistance is achieved at the sliding parts. Therefore, by including a hermetic refrigeration compressor with these advantages in the refrigeration and freezing unit, the power consumption of the refrigeration and freezing unit can be reduced, and the refrigeration and freezing unit can also be made highly reliable.

[0014] The above-mentioned and other objects, features and advantages of the present invention will become more fully apparent from the following detailed description of preferred embodiments taken in conjunction with the accompanying drawings. Beneficial effects of the invention

[0015] The present invention is constructed as described above and has the advantage of providing a sealed refrigeration compressor that can effectively suppress the reduction of wear resistance of sliding parts even when using lubricating oil with low viscosity. Attached Figure Description

[0016] Figure 1 This is a schematic cross-sectional view illustrating an example of the construction of a hermetically sealed refrigeration compressor according to an embodiment of the present disclosure. Figure 2 This is a scatter plot showing the relationship between the kinematic viscosity and surface tension of the lubricating oil used in a hermetically sealed refrigeration compressor according to an embodiment of the present disclosure. Figure 3 It shows including Figure 1 A schematic diagram illustrating an example configuration of a refrigeration and freezing unit with a refrigeration compressor. Detailed Implementation

[0017] The hermetically sealed refrigeration compressor according to this disclosure includes a hermetically sealed container in which a substance with a kinematic viscosity of 1 mm at 40°C is stored. 2 / S to 10mm 2 The lubricating oil is within the range of / S, and the sealed container houses electrical components and a compression element, which is driven by the electrical components and configured to compress the refrigerant. The lubricating oil has a surface tension in the range of 23 mN / m to 45 mN / m.

[0018] According to the above structure, the lubricating oil stored in the sealed container has low viscosity and high surface tension. Therefore, at the sliding part included in the compression element, the oil film formed between the sliding surfaces can be maintained as a thin film. Thus, even if the oil film forms a thin film, its rupture can be effectively suppressed. Therefore, while improving the efficiency of the sealed refrigeration compressor, it is advantageous to suppress the reduction of wear resistance at the sliding part.

[0019] In a hermetically sealed refrigeration compressor with the above-described structure, the surface tension of the lubricating oil can be in the range of 25 mN / m to 35 mN / m.

[0020] According to the above structure, the surface tension of the lubricating oil stored in the sealed container is within a more preferred range. Therefore, the rupture of the thin oil film at the sliding parts can be suppressed more effectively. Thus, while improving the efficiency of the sealed refrigeration compressor, the reduction of wear resistance at the sliding parts can be advantageously suppressed.

[0021] In the hermetic refrigeration compressor configured as described above, the lubricating oil may contain a surface tension modifier, which is a sulfur-based compound or a phosphorus-based compound.

[0022] Based on the above structure, since the low-viscosity lubricating oil contains a surface tension modifier, the surface tension can be adjusted within the aforementioned range. Therefore, the rupture of the thin oil film at the sliding parts can be more effectively suppressed. Thus, while improving the efficiency of the sealed refrigeration compressor, it is advantageously possible to suppress the reduction of wear resistance at the sliding parts.

[0023] In the hermetic refrigeration compressor configured as described above, electrical components can be driven by the inverter at multiple operating frequencies.

[0024] Based on the above structure, when the electrical components are driven by an inverter, a thin film of lubricating oil with low viscosity and high surface tension is maintained at the sliding part, regardless of whether the operation is at low or high speed. Therefore, good wear resistance can be achieved at the sliding part, improving the reliability of the hermetically sealed refrigeration compressor.

[0025] The refrigeration and freezing apparatus according to this disclosure includes a refrigerant circuit comprising: a hermetically sealed refrigeration compressor as described above; a radiator; a pressure reducer; and a heat absorber. In the refrigerant circuit, the hermetically sealed refrigeration compressor, radiator, pressure reducer, and heat absorber are connected in a loop via piping.

[0026] According to the above structure, since the hermetic refrigeration compressor uses a lubricating oil with low viscosity and high surface tension, good wear resistance is achieved at the sliding parts. Therefore, by including a hermetic refrigeration compressor with these advantages in the refrigeration and freezing unit, the power consumption of the refrigeration and freezing unit can be reduced, and the refrigeration and freezing unit can also be made highly reliable.

[0027] In the following description, representative embodiments of the invention are illustrated with reference to the accompanying drawings. In the drawings, the same or corresponding elements are indicated by the same reference numerals, and repetition of the same descriptions is avoided below.

[0028] (Example 1) [Structure of a Refrigeration Compressor] First, refer to Figure 1 Here is a specific example of the construction of a hermetically sealed refrigeration compressor according to Embodiment 1 of this disclosure. Figure 1This is a schematic cross-sectional view showing an example of the construction of a hermetically sealed refrigeration compressor 100 according to Embodiment 1 of the present disclosure (hereinafter, the hermetically sealed refrigeration compressor 100 may be simply referred to as "refrigeration compressor 100").

[0029] like Figure 1 As shown, the refrigeration compressor 100 includes a sealed container 101 filled with refrigerant (e.g., R600a). Mineral oil, as lubricating oil 103, is stored at the bottom of the sealed container 101. In this disclosure, the lubricating oil 103 has a viscosity of 1 mm at 40°C. 2 / S to 10mm 2 It has a kinematic viscosity in the range of / S and a surface tension in the range of 23mN / m to 45mN / m. It should be noted that, in Example 1, although the lubricating oil 103 is a low-viscosity mineral oil, the lubricating oil 103 is not limited to mineral oil, as described below.

[0030] Additionally, an electrical component 106 and a compression component 107 are housed within the sealed container 101. The electrical component 106 consists of a stator 104 and a rotor 105. The compression component 107 is a reciprocating element driven by the electrical component 106. The compression component 107 includes, for example, a crankshaft 108, a cylinder block 112, and a piston 120.

[0031] The crankshaft 108 comprises a main shaft 109 and an eccentric shaft 110. The rotor 105 is fixed to the main shaft 109 by press fitting. The eccentric shaft 110 is formed to be eccentric to the main shaft 109. In Embodiment 1, the outer peripheral surface of the main shaft 109 of the crankshaft 108 serves as a sliding surface. In this disclosure, the term "sliding surface" refers to the outer or inner peripheral surface of each sliding member forming a sliding portion, and such outer or inner peripheral surface slidably contacts another inner or outer peripheral surface. An oil pump (not shown) is provided at the lower end of the crankshaft 108.

[0032] In embodiment 1, for example, the cylinder block 112 is made of cast iron. The cylinder block 112 forms a generally cylindrical bore 113 and includes a main bearing 114 that pivotally supports the main shaft 109 of the crankshaft 108. The inner circumferential surface of the main bearing 114 is in sliding contact with the outer circumferential surface (i.e., the sliding surface) of the main shaft 109. Therefore, the inner circumferential surface of the main bearing 114 also serves as the sliding surface. It should be noted that either the entire outer circumferential surface of the main shaft 109 or the entire inner circumferential surface of the main bearing 114 can also serve as the sliding surface. Alternatively, a portion of the outer circumferential surface of the main shaft 109 or a portion of the inner circumferential surface of the main bearing 114, rather than the entire outer circumferential surface, can also serve as the sliding surface.

[0033] It should be noted that, such as Figure 1As shown, the eccentric shaft 110 of the crankshaft 108 is located above the refrigeration compressor 100, while the main shaft 109 of the crankshaft 108 is located below the refrigeration compressor 100. Therefore, this vertical positional relationship (direction) is used when describing the position on the crankshaft 108 here. For example, the upper end of the eccentric shaft 110 faces the inner upper surface of the sealed container 101, and the lower end of the eccentric shaft 110 is connected to the main shaft 109. The upper end of the main shaft 109 is connected to the eccentric shaft 110, and the lower end of the main shaft 109 faces the inner lower surface of the sealed container 101. The lower end of the main shaft 109 is immersed in lubricating oil 103.

[0034] The non-sliding outer peripheral surface constitutes a portion of the outer peripheral surface of the spindle 109. However, unlike the first sliding surface and the second sliding surface of the outer peripheral surface of the spindle 109, the non-sliding outer peripheral surface is a surface recessed (or sunken) from the sliding surfaces (the first sliding surface and the second sliding surface), such that the non-sliding outer peripheral surface does not contact the inner peripheral surface of the bearing portion. In other words, the diameter or radius of the portion of the spindle 109 that serves as the sliding surface is larger than the diameter or radius of the portion of the spindle 109 that serves as the non-sliding outer peripheral surface.

[0035] The piston 120 is inserted into the bore 113 in a reciprocating manner, thereby forming a compression chamber 121. A piston pin 115, having a generally cylindrical shape, is disposed parallel to the eccentric shaft 110. The piston pin 115 is locked in a non-rotatable manner into a piston pin bore formed in the piston 120.

[0036] The connector 117 is made, for example, of an aluminum casting. The connector 117 includes an eccentric bearing 119 that pivotally supports the eccentric shaft 110, and the connector 117 connects the eccentric shaft 110 and the piston 120 via a piston pin 115. The end face of the bore 113 is sealed by a valve plate 122.

[0037] It should be noted that in this disclosure, the main shaft 109 and the eccentric shaft 110 included in the crankshaft 108 are collectively referred to as "shaft portions". In addition, the main bearing 114 of the cylinder block 112 (pivotibly supporting the main shaft 109) and the eccentric bearing 119 of the coupling 117 (pivotibly supporting the eccentric shaft 110) are collectively referred to as the aforementioned "bearing portions".

[0038] Cylinder head 123 forms a high-pressure chamber (not shown) and is fixed to valve plate 122 on the side opposite to bore 113. Suction pipe (not shown) is fixed to sealed container 101 and also connected to the low-pressure side (not shown) of the refrigeration cycle; the suction pipe introduces refrigerant gas into sealed container 101. Suction muffler 124 is held between valve plate 122 and cylinder head 123 in a clamping manner.

[0039] The crankshaft 108's main shaft 109 and main bearing 114, piston 120 and bore 113, piston pin 115 and connecting rod of connector 117, and crankshaft 108's eccentric shaft 110 and connector 117's eccentric bearing 119 form sliding parts with each other.

[0040] In the refrigeration compressor 100 configured in this way, power is first supplied from a commercial power source (not shown) to the electrical components 106 to rotate the rotor 105 of the electrical components 106. The rotor 105 rotates the crankshaft 108, and the eccentric movement of the eccentric shaft 110 from the coupling 117 drives the piston 120 via the piston pin 115. The piston 120 reciprocates in the bore 113, and refrigerant gas, which has been introduced into the sealed container 101 through the suction pipe, is drawn in from the suction muffler 124 and compressed in the compression chamber 121.

[0041] It should be noted that the specific method of driving the refrigeration compressor 100 is not particularly limited. For example, the refrigeration compressor 100 can be driven by simple on-off control, or it can be driven by an inverter at multiple operating frequencies. When the refrigeration compressor 100 is driven by an inverter, low-speed operation or high-speed operation is performed to optimize the operation control of the refrigeration compressor 100. When low-speed operation is performed, the amount of oil supplied to each sliding part is reduced, while when high-speed operation is performed, the rotational speed of the electrical component 106 is increased. In the refrigeration compressor 100, the wear resistance of the main shaft 109 can be improved as described later. Therefore, the reliability of the refrigeration compressor 100 can be improved.

[0042] In the multiple sliding portions included in the refrigeration compressor 100, the main shaft 109 of the crankshaft 108 is rotatably adapted to the main bearing 114, thereby forming a sliding portion. Similarly, the eccentric shaft 110 of the crankshaft 108 is rotatably adapted to the eccentric bearing 119, thereby forming a sliding portion. Furthermore, the piston 120 and bore 113, or the piston pin 115 and coupling 117, also form sliding portions. Depending on the rotation of the crankshaft 108, an oil pump supplies lubricating oil 103 to each of these sliding portions.

[0043] [Composition of Lubricating Oil] Next, a more detailed description will be given of the composition of the lubricating oil 103 stored in the sealed container 101.

[0044] According to this disclosure, the lubricating oil 103 is not limited to a specific type of lubricating oil, as long as the lubricating oil 103 has the property of maintaining a viscosity of 1 mm at 40°C. 2 / S to 10mm 2 It has a kinematic viscosity in the range of / S and a surface tension in the range of 23mN / m to 45mN / m.

[0045] Typically, for example, at least one oily substance selected from the group consisting of mineral oils, alkylbenzene oils, and ester oils may be suitably used as lubricant 103. Only one of these oily substances may be used as lubricant 103, or a suitable combination of two or more oily substances may be used as lubricant 103. The definition of a combination of two or more different oily substances herein includes not only combinations of two or more different oily substances, such as mineral oils, but also, for example, one or more oily substances that are each mineral oils and one or more oily substances that are each alkylbenzene oils (or one or more oily substances that are each ester oils).

[0046] As previously stated, the lubricating oil 103 according to this disclosure needs to have a temperature of 1 mm at 40°C. 2 / S to 10mm 2 Kinematic viscosity within the range of / s. A preferred example of the kinematic viscosity range at 40°C is 1 mm. 2 / S to 9mm 2 / S. If the kinematic viscosity at 40℃ is less than 1 mm. 2 If the surface tension of the lubricating oil 103 is less than 10 m / s, the viscosity becomes too low. In this case, even if the surface tension of the lubricating oil 103 is in the range of 23 mN / m to 45 mN / m, an oil film that can be well maintained on the sliding parts cannot be formed. On the other hand, if the kinematic viscosity at 40°C is greater than 10 mm... 2 If / S, then the lubricating oil 103 is no longer a "low viscosity oil", which affects the sliding of the sliding parts to each other, and therefore may hinder the realization of improved efficiency of the sliding parts.

[0047] As previously stated, the lubricating oil 103 according to this disclosure needs to have a surface tension in the range of 23 mN / m to 45 mN / m. A preferred example of the surface tension range is 25 mN / m to 35 mN / m. If the surface tension of the lubricating oil 103 is less than 23 mN / m, the surface tension is too low. In this case, an oil film that can be well maintained on the sliding parts cannot be formed. On the other hand, if the surface tension of the lubricating oil 103 is greater than 45 mN / m, the surface tension is too high, which affects the sliding of the sliding parts relative to each other, and therefore may hinder the improvement of the efficiency of the sliding part.

[0048] Actual machine reliability testing was conducted on the refrigeration compressor 100, which used a low-viscosity, high-surface-tension lubricating oil 103. In this test, R600a was used as the refrigerant gas. Figure 2 As shown, a total of 7 types of lubricating oil 103 were used, and the kinematic viscosity of each lubricating oil at 40°C was less than 1 mm. 2 / S to 10mm 2The surface tension is between 20 mN / m and 45 mN / m. For the sliding parts to be evaluated, the crankshaft 108's main shaft 109 and main bearing 114 are selected. Furthermore, to accelerate the wear of the main shaft 109, a high-temperature and high-load intermittent operation mode involving repeated starting and stopping in a short time under high-temperature conditions is adopted as the operating mode.

[0049] After the actual machine reliability test was completed, the refrigeration compressor 100 was disassembled and the crankshaft 108 was removed. The sliding parts were then observed. The results were as follows: Figure 2 As indicated by the symbol "X", in the test results where the surface tension of each lubricating oil 103 was less than 23 mN / m, it was confirmed that the spindle 109 was significantly worn. On the other hand, as... Figure 2 The "circle" and "triangle" symbols indicate that in the test results where the surface tension of each lubricating oil 103 is greater than or equal to 23 mN / m, almost no wear on the spindle 109 or only minor wear on the spindle 109 was observed.

[0050] However, in the case of Figure 2 In the test results represented by the "triangle" symbol, although the surface tension of the lubricating oil 103 is approximately 42 mN / m, the wear of the spindle 109 is greater than that represented by the "circle" symbol. Therefore, in this disclosure, where the surface tension of the lubricating oil 103 is required to be in the range of 23 mN / m to 45 mN / m, a preferred example of the surface tension range is 25 mN / m to 35 mN / m. It should be noted that the method used to measure surface tension is not particularly limited. In this embodiment, the du Noüy ring method as defined in JIS K2241 is used, and the DY-300 (trade name) manufactured by Kyowa Interface Science Co., LTD. is used as the surface tension measuring device.

[0051] According to this disclosure, the method for adjusting the surface tension of the lubricating oil 103 to fall within the aforementioned range is not particularly limited. For example, a commercially available oily substance that satisfies the aforementioned kinematic viscosity and surface tension can be used as lubricating oil 103, or multiple oily substances can be mixed together to adjust the kinematic viscosity and surface tension of the resulting oily substance mixture to the aforementioned kinematic viscosity and surface tension. Furthermore, a surface tension modifier can be added to (or included in) one or more oily substances to adjust the surface tension. Therefore, the lubricating oil 103 used in the refrigeration compressor 100 according to this disclosure needs to contain at least one oily substance (as its main component (multiple main components)) and can be a lubricating oil composition consisting of at least one or more oily substances and a surface tension modifier.

[0052] There are no particular restrictions on the specific type of surface tension modifier, as long as when the surface tension modifier is added to a known oily substance (i.e., when the surface tension modifier and the known oily substance constitute a lubricating oil composition), the surface tension modifier allows the surface tension of the oily substance (lubricating oil composition) to fall within the aforementioned range.

[0053] Representative examples of surface tension modifiers include sulfur-based and phosphorus-based compounds. Specific examples of sulfur-based compounds include, but are not particularly limited to, sulfurized alkenes, sulfur-based compounds (e.g., dibenzyl disulfide (DBDS)), xanthate esters, thiadiazoles, thiocarbonates, sulfurized oils or fats, sulfurized esters, dithiocarbamates, and sulfurized terpenes. Specific examples of phosphorus-based compounds include, but are not particularly limited to, tricresyl phosphate (TCP), tributyl phosphate (TBP), and triphenyl phosphate (TPP). Only one of these compounds can be used as a surface tension modifier, or a suitable combination of two or more of these compounds can be used as a surface tension modifier.

[0054] The content of surface tension modifier in the lubricating oil composition is not particularly limited and can be appropriately set according to various conditions, such as the type of oily substance, the required surface tension range, and the more specific construction of the refrigeration compressor 100. Generally, if the total amount of the lubricating oil composition is 100% by weight, it is required that the lubricating oil composition contain 0.01 to 8% by weight of surface tension modifier. As a more preferred example, the lubricating oil composition may contain 1 to 3% by weight of surface tension modifier. If the content of surface tension modifier in the lubricating oil composition is less than 0.01% by weight, there is a risk that the surface tension may not be adjusted to the required value, and the oil film may rupture, although this depends on various conditions. On the other hand, if the content of surface tension modifier in the lubricating oil composition is greater than 8% by weight, the surface tension may remain unchanged, although this depends on various conditions.

[0055] In addition to the aforementioned oily substances and surface tension modifiers, various additives may be added to the lubricating oil 103 (lubricating oil composition) according to this disclosure. As various additives to be added to the lubricating oil 103, additives known in the art of lubricating oil 103 may be appropriately used. Typical examples of such additives include extreme pressure additives, oiliness agents, anti-wear agents, antioxidants, acid binders, metal passivators, defoamers, corrosion inhibitors, and dispersants. The specific types and amounts of these additives are not particularly limited and can be added within the known range.

[0056] Next, referring to the operation of the refrigeration compressor 100 configured as described above, the lubricating effect of the lubricating oil 103 will be explained. Power is supplied to the electrical component 106 from a commercial power source (not shown) to rotate the rotor 105 of the electrical component 106. The rotor 105 rotates the main shaft 109 of the crankshaft 108, and the eccentric movement of the eccentric shaft 110 from the coupling 117 drives the piston 120 via the piston pin 115. The piston 120 reciprocates in the bore 113, and the refrigerant gas, which has been introduced into the sealed container 101 through the suction pipe (not shown), is drawn in from the suction muffler 124 and compressed in the compression chamber 121.

[0057] As the crankshaft 108 rotates, an oil pump (not shown) supplies lubricating oil 103 to each sliding part, thereby lubricating the sliding parts. Sliding components forming the sliding parts include, for example, the main shaft 109 and main bearing 114, the eccentric shaft 110 and eccentric bearing 119 (of the coupling 117), the piston pin 115 and coupling 117, and the piston 120 and bore 113. Lubricating oil 103 is supplied to the sliding surfaces of these sliding components. Additionally, the lubricating oil 103 also serves to seal between the piston 120 and the bore 113.

[0058] In recent years, several measures have been taken to further improve the efficiency of refrigeration compressors 100, such as using lubricating oil with low viscosity as lubricant 103 and designing the length of the sliding surface of each sliding member forming the sliding part to be shorter. For these reasons, the sliding conditions become more demanding. Specifically, the oil film between the sliding parts tends to be thinner, or the oil film between the sliding parts tends to break more easily. Therefore, at the sliding parts, such as between the main shaft 109 of the crankshaft 108 and the main bearing 114, oil film rupture is prone to occur, and the metal of the sliding surfaces comes into contact more frequently.

[0059] In this respect, in the refrigeration compressor 100 according to this disclosure, the lubricating oil 103 has a temperature of 1 mm at 40°C. 2 / S to 10mm 2 It has a kinematic viscosity in the range of / S and a surface tension in the range of 23mN / m to 45mN / m. By using a lubricant 103 with these characteristics, a thin oil film can be well maintained at each sliding part, and the rupture of the oil film can be effectively suppressed. Therefore, while improving the efficiency of the hermetic refrigeration compressor, it is advantageous to suppress the reduction of wear resistance at the sliding parts.

[0060] It should be noted that, as previously stated, the refrigeration compressor 100 according to this disclosure can be driven by an inverter at multiple operating frequencies. When the refrigeration compressor 100 is driven by an inverter, there are two operating modes for the electrical component 106: in one mode, the electrical component 106 operates at a low rotational speed (low-speed operation), and in the other mode, the electrical component 106 operates at a high rotational speed (high-speed operation). When the electrical component 106 operates at a low rotational speed, the amount of lubricating oil 103 supplied to the main shaft 109 of the crankshaft 108 and the main bearing 114 (i.e., the sliding portion of the main shaft 109) is reduced. In this respect, in this disclosure, since the lubricating oil 103 has the low viscosity and high surface tension described above, good wear resistance can be achieved at the sliding portion of the main shaft 109 even when the amount of lubricating oil 103 supplied to the sliding portion of the main shaft 109 is reduced.

[0061] Furthermore, even when the rotational speed of the electrical component 106 changes from a low speed to a high speed (i.e., when the rotational speed of the electrical component 106 increases), good wear resistance of the sliding portion of the main shaft 109 can be achieved. Therefore, when the refrigeration compressor 100 is driven by the inverter, good wear resistance at the sliding portion can be achieved regardless of whether it is operating at low speed or high speed. As a result, the reliability of the refrigeration compressor 100 can be improved, and its operating efficiency can be increased.

[0062] (Example 2) In this embodiment 2, reference Figure 3 Here is an example of a refrigeration and freezing apparatus equipped with the refrigeration compressor 100 described in Embodiment 1 above. Figure 3 This is a schematic diagram illustrating the refrigeration and freezing apparatus including the refrigeration compressor 100 according to Embodiment 1. Therefore, in Embodiment 2, only the basic configuration of the refrigeration and freezing apparatus is briefly described.

[0063] like Figure 3 As shown, the refrigeration and freezing apparatus according to Embodiment 2 includes, for example, a main body 275, an isolation wall 278, and a refrigerant circuit 270. The main body 275 includes an insulated enclosure, a door, etc. The enclosure is configured to have an opening, and the door is configured to open / close the opening of the enclosure. The interior of the main body 275 is divided by the isolation wall 278 into a storage space 276 for articles and a machine compartment 277. A blower (not shown) is provided in the storage space 276. It should be noted that the interior of the main body 275 can be divided into spaces, for example, different from the storage space 276 and the machine compartment 277.

[0064] The refrigerant circuit 270 is configured to cool the interior of the storage space 276. For example, the refrigerant circuit 270 includes the refrigeration compressor 100, radiator 272, pressure reducer 273, and absorber 274 described in Embodiment 1 above, which are connected in a ring-like manner via pipes. The absorber 274 is disposed within the storage space 276. The cooling heat from the absorber 274 is circulated within the storage space 276 by agitation using a blower (not shown). Figure 3 As shown by the dashed arrow in the diagram. In this way, the interior of storage space 276 is cooled.

[0065] As shown in Example 1 above, the lubricating oil 103 used in the refrigeration compressor 100 included in the refrigerant circuit 270 has a particle size of 1 mm at 40°C. 2 / S to 10mm 2 It exhibits a kinematic viscosity within the range of / S and a surface tension within the range of 23 mN / m to 45 mN / m. Therefore, it is possible to achieve good wear resistance in the sliding parts constituting the refrigeration compressor 100. Consequently, the reliability of the refrigeration compressor 100 can be improved.

[0066] As described above, the refrigeration and freezing apparatus of Embodiment 2 includes the refrigeration compressor 100 of Embodiment 1. In the refrigeration compressor 100, a low-viscosity lubricating oil 103 is used; the sliding area of ​​the sliding part of the shaft is reduced; and the reliability of the shaft is improved. Since the refrigeration and freezing apparatus includes a hermetically sealed refrigeration compressor, which is highly efficient and reliable, the power consumption of the refrigeration and freezing apparatus can be reduced, and the refrigeration and freezing apparatus can also be made highly reliable.

[0067] It should be noted that the present invention is not limited to the above embodiments, and various modifications can be made within the scope of the claims. Embodiments obtained by appropriately combining the technical means disclosed in different embodiments and variations also fall within the technical scope of the present invention.

[0068] Based on the foregoing description, numerous modifications and other embodiments of the present invention will be apparent to those skilled in the art. Therefore, the above description should be interpreted as illustrative only and is provided for the purpose of teaching those skilled in the art the best mode for carrying out the invention. Substantial modifications to the construction and / or functional details may be made without departing from the spirit of the invention. Industrial applicability

[0069] As described above, according to the present invention, a refrigeration compressor using low-viscosity lubricating oil and exhibiting excellent reliability can be provided, and a refrigeration and freezing apparatus using the refrigeration compressor can be provided. Therefore, the present invention can be widely applied to various devices that utilize refrigeration cycles. Figure Labels

[0070] 100: Refrigeration compressor 101: Sealed Container 103: Lubricating oil 106: Electrical Components 107: Compression Component 108: Crankshaft 109: Spindle (shaft section) 110: Eccentric shaft (shaft portion) 112: Cylinder block 113: Hole (sliding component) 114: Main bearing (sliding component) 115: Piston pin (sliding component) 119: Eccentric bearing (sliding component) 120: Piston (sliding component) 121: Compression Chamber 270: Refrigerant Circuit 272: Radiator 273: Pressure Reducer 274: Heat absorber

Claims

1. A hermetically sealed refrigeration compressor, comprising a hermetically sealed container in which a substance with a kinematic viscosity of 1 mm at 40°C is stored. 2 / s to 4 mm 2 The sealed container houses an electrical component and a compression component, which are driven by the electrical component and configured to compress the refrigerant. The refrigerant is within a range of [value missing]. The lubricating oil includes mineral oil and has a surface tension in the range of 23 mN / m to 45 mN / m when the surface tension is measured by the ring method as defined in JIS K2241.

2. The hermetically sealed refrigeration compressor according to claim 1, wherein... The compression element is a reciprocating element driven by the electrical element, and includes a crankshaft and a cylinder block, and The crankshaft's main shaft is pivotally supported by a main bearing included in the cylinder block.

3. The hermetically sealed refrigeration compressor according to claim 1, wherein... The refrigerant is R600a.

4. The hermetically sealed refrigeration compressor according to claim 1, wherein The surface tension of the lubricating oil is in the range of 25 mN / m to 35 mN / m.

5. The hermetically sealed refrigeration compressor according to claim 1, wherein... The lubricating oil contains a surface tension modifier, which is a sulfur-based compound or a phosphorus-based compound.

6. The hermetically sealed refrigeration compressor according to claim 1, wherein... The electrical components are driven by the inverter at multiple operating frequencies.

7. A refrigeration-freezing apparatus, comprising a refrigerant circuit, the refrigerant circuit comprising: The hermetically sealed refrigeration compressor according to claim 1; heat sink; Pressure reducer; as well as Heat absorber, among which In the refrigerant circuit, the hermetically sealed refrigeration compressor, the radiator, the pressure reducer, and the heat absorber are connected in a ring-shaped manner via pipes.

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