JP2020012375A - Refrigerant compressor and refrigerator using it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a highly reliable and highly efficient refrigerant compressor by improving wear resistance and early conformability of a sliding member. A hard coating (160) having a hardness equal to or higher than that of a main bearing (111) which is a mating sliding member is formed on the surface of a base material of a main shaft (109), and the mating sliding member is formed on the surface of the hard coating. A soft coating 170 having a hardness smaller than that of the above is formed. As a result, even when the oil film thickness between the sliding members becomes thin during low speed operation, etc., due to the initial conformability of the soft film formed on the surface of the hard film, the hard film and the main bearing that is the mating sliding member It is possible to avoid direct solid contact with 111, to provide a highly efficient and highly reliable refrigerant compressor with low input from the initial stage of operation. [Selection diagram] Figure 2

Description

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

  In recent years, in order to reduce the amount of fossil fuel used from the viewpoint of global environmental protection, development of a high-efficiency refrigerant compressor has been promoted.

  The high-efficiency refrigerant compressor forms a phosphate film on the sliding surface to prevent abrasion of a sliding portion such as a crankshaft, and the formation of the phosphate film forms a machined finish. Measures have been taken to eliminate irregularities on the processed surface and to improve the initial familiarity between sliding members (for example, see Patent Document 1).

  FIG. 7 shows a cross section of a conventional refrigerant compressor described in Patent Document 1. As shown in FIG.

  As shown in FIG. 7, a hermetic container 1 serving as an outer casing of a refrigerant compressor stores a lubricating oil 2 at a bottom portion, and includes an electric element 5 including a stator 3 and a rotor 4, and a reciprocating type driven by the electric element 5. Of the compression element 6 are accommodated.

  The compression element 6 includes a crankshaft 7, a cylinder block 11, a piston 15, and the like.

  The crankshaft 7 includes a main shaft 8 to which the rotor 4 is press-fitted and fixed, an eccentric shaft 9 formed eccentrically with respect to the main shaft 8, and includes an oil supply pump 10.

  The cylinder block 11 forms a compression chamber 13 composed of a substantially cylindrical cylinder bore 12 and has a main bearing 14 that supports the main shaft 8.

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

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

  The main shaft 8 and the main bearing 14 of the crankshaft 7, the piston 15 and the cylinder bore 12, the piston pin 16 and the connecting rod 17, the eccentric shaft 9 of the crankshaft 7 and the connecting rod 17 mutually constitute a sliding part.

  Among the sliding members constituting the sliding portion, in a combination of iron-based materials, the phosphate film is formed on one of the sliding portion surfaces as described above.

  The operation of the above configuration will be described below.

Electric power supplied from a commercial power supply (not shown) is supplied to the electric element 5 to rotate the rotor 4 of the electric element 5. The rotator 4 rotates the crankshaft 7 and drives the piston 15 via the connecting rod 17 and the piston pin 16 of the connecting means by the eccentric movement of the eccentric shaft 9. The piston 15 reciprocates in the cylinder bore 12, sucks the refrigerant gas guided into the closed casing 1 through the suction tube 20, and continuously compresses the compressed gas in the compression chamber 13.

  The lubricating oil 2 is supplied to each sliding portion from the oil supply pump 10 with the rotation of the crankshaft 7, lubricates each sliding portion, and controls a seal between the piston 15 and the cylinder bore 12.

  Here, the main shaft 8 and the main bearing 14 of the crankshaft 7 are rotating, and the rotation speed is 0 m / s when the refrigerant compressor is stopped, and the rotation starts from the metal contact state when the refrigerant compressor is started. As a result, a large frictional resistance is applied.

  In this type of refrigerant compressor, a phosphate film is formed on the main shaft 8 of the crankshaft 7, and the phosphate film has an initial conformability, so that abnormal wear due to metal contact at startup can be prevented.

  However, in recent years, in order to improve the efficiency of the refrigerant compressor, the lubricating oil 2 having a lower viscosity is used, or the sliding length between the sliding members is designed to be shorter. In the case of the phosphate film, there was a possibility that wear or abrasion would occur at an early stage, it would be difficult to maintain a conforming effect, and abrasion resistance would decrease.

  Further, the load applied to the main shaft 8 during one rotation of the crankshaft 7 greatly fluctuates, and the refrigerant gas dissolved in the lubricating oil 2 flows between the main shaft 8 and the main bearing 14 due to the load fluctuation. And may foam, thereby increasing the frequency of breaking the oil film and making metal contact. As a result, there is a concern that the phosphate film formed on the main shaft 8 is worn away early and the friction coefficient is increased, and accordingly, the heat generation of the sliding portion is increased, thereby causing abnormal wear such as adhesion.

  Therefore, as a measure to cope with this, there is a method of increasing the yield strength by forming a hard and dense compound layer, a so-called nitrocarburized film, on the sliding surface in a gas atmosphere or by immersion in a salt bath. Reference 2).

  In this refrigerant compressor, a soft nitrided film is formed on the main shaft 8 of the crankshaft 7, and the soft nitrided film generally has an HV (Vickers hardness) of 600 or more and has high mechanical strength. Abnormal wear due to metal contact at the time can be prevented.

JP-A-7-238885 JP-B-55-4958

  However, in recent years, in order to increase the efficiency of the refrigerant compressor, low-speed operation (for example, less than 20 Hz) by an inverter drive has been increasingly advanced, and a nitrocarburized film used for application to severe low-speed lubrication conditions has been developed. In addition, since the sliding surfaces are hard to be readily adapted to each other due to being hard and having a very high proof stress, there is a possibility that a sliding loss may increase particularly in an initial operation or in a low speed operation range.

This is because many small projections exist between the sliding members, for example, in both the main shaft 8 and the main bearing 14 in the roughness region, and when the operation is performed at a lower speed, the oil film thickness between the sliding members decreases. This is due to the frequent occurrence of solid contact in the roughness region. As a result, when a hard and high mechanical strength film such as a conventional nitrocarburized film is formed on the surface of the sliding member, the progress of abrasion of the projections in the roughness region is significantly slowed down upon solid contact. In addition, there is a concern that the operation in a state where the input is high from the beginning of the operation is continued for a long time.

  The present invention has been made in view of such a point, and by improving the wear resistance and early adaptability of a sliding member, a highly reliable, high-efficiency refrigerant compressor and a combination thereof have been used. An object is to provide a refrigeration apparatus.

  In order to achieve the above object, the refrigerant compressor of the present invention forms a hard coating having a hardness equal to or more than that of a mating sliding member on the surface of the sliding member, and also covers the entire surface of the hard coating or In some parts, a soft coating having a hardness smaller than that of the sliding member is formed.

  As a result, even if the oil film thickness between the sliding members becomes thin and solid contact with the mating sliding member occurs, an input from the initial operation due to the initial conformability of the soft film formed on the surface of the hard film. A low, highly efficient and highly reliable refrigerant compressor can be provided.

  Further, a refrigeration apparatus according to the present invention is configured to include the refrigerant compressor having the above-described configuration, a radiator, a pressure reducing device, and a refrigerant circuit in which a heat absorber is connected in a ring shape.

  This allows the refrigeration apparatus to be equipped with a refrigerant compressor with improved performance and reliability, thereby reducing power consumption, realizing energy saving, and improving reliability.

  According to the present invention, in addition to the configuration described above, the viscosity of the lubricating oil is lower and the sliding length between the sliding parts can be designed to be shorter. It is possible to provide a highly reliable and highly efficient refrigerant compressor and a refrigeration apparatus using the same, which can reduce the sliding loss from the initial operation.

Sectional view of a refrigerant compressor according to Embodiment 1 of the present invention. FIG. 2 is a schematic view showing a cross section of the sliding portion A of FIG. SIM image showing an example of the result of SIM (scanning ion microscope) observation of the coating on the spindle surface used in the embodiment. Characteristic diagram showing the hardness in the depth direction of the main shaft and the main bearing in the same embodiment FIG. 5 is a time-series change curve of the input of the refrigerant compressor and the COP in the embodiment. FIG. 4 is a schematic diagram illustrating a configuration of a refrigeration apparatus according to Embodiment 2 of the present invention. Cross section of conventional refrigerant compressor

  According to a first aspect of the present invention, there is provided an electric element housed in a closed container, a compression element driven by the electric element to compress a refrigerant, a lubricating oil for lubricating between sliding members forming the compression element, A hard coating having a hardness equal to or greater than that of the mating sliding member is formed on the surface of the moving member, and the entire surface or a part of the surface of the hard coating is formed of a soft material having a hardness smaller than that of the mating sliding member. It has a configuration in which a film is formed.

  As a result, even if the oil film thickness between the sliding members becomes thin and solid contact with the mating sliding member occurs, an input from the initial operation due to the initial adaptability of the soft film formed on the surface of the hard film. A low, highly efficient and highly reliable refrigerant compressor can be provided.

  In the second invention, in particular, the soft coating of the first invention has a configuration containing a resin as a main component.

  This makes it possible to eliminate irregularities on the surface of the hard film and easily form a smooth surface, and since the resin has initial conformability, the metal film is formed when the oil film is not formed at the start of operation. Abnormal wear due to contact can be prevented, sliding loss can be reduced from the beginning of operation, and a highly reliable and highly efficient refrigerant compressor can be provided.

  In the third invention, the resin of the second invention is a resin containing a solid lubricant.

  As a result, even when an oil film is not formed at the time of starting operation, the friction coefficient can be reduced by the solid lubricant, so that the sliding loss can be reduced even under poor oil conditions, and the sliding surfaces can be reduced. Can be reduced, so that a more efficient and highly reliable refrigerant compressor can be provided.

  In a fourth aspect, in particular, in any one of the first to third aspects, the electric element is driven by an inverter at a plurality of operation frequencies including an operation frequency equal to or lower than the commercial power supply frequency.

  As a result, even during low-speed operation in which the amount of lubrication to each sliding portion is reduced, the soft coating having good conformability can avoid solid contact between the hard coating and the mating sliding member. Thus, a highly efficient and highly reliable refrigerant compressor can be provided.

  The fifth invention is a refrigeration apparatus, which has a refrigerant circuit in which a refrigerant compressor, a radiator, a decompression device, and a heat sink are connected in a ring by piping. It is configured as a refrigerant compressor of any one of the inventions.

  Thereby, the power consumption of the refrigerating apparatus can be reduced by mounting the compressor with improved performance and reliability, energy saving can be realized, and reliability can be improved.

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

(Embodiment 1)
FIG. 1 is a sectional view of a refrigerant compressor according to Embodiment 1 of the present invention.

  In FIG. 1, a refrigerant compressor 100 includes a closed vessel 101 filled with R600a as a refrigerant gas 102, a mineral oil as a lubricating oil 103 at a bottom thereof, and an electric element 106 including a stator 104 and a rotor 105. And a reciprocating compression element 107 driven thereby.

  The compression element 107 includes a crankshaft 108, a cylinder block 112, a piston 132, and the like. The configuration will be described below.

  The crankshaft 108 includes a main shaft 109 into which the rotor 105 is press-fitted and fixed, and an eccentric shaft 110 formed eccentrically with respect to the main shaft 109, and has a lower end provided with an oil supply pump 120 communicating with the lubricating oil 103.

  The cylinder block 112 is made of cast iron, forms a substantially cylindrical cylinder bore 113, and has a main bearing 111 that supports the main shaft 109 by integral molding.

  The piston 132 is reciprocally inserted into the cylinder bore 113. The piston pin 115 has a substantially cylindrical shape, is disposed parallel to the eccentric shaft 110, and is non-rotatably locked in a piston pin hole 116 formed in the piston 132. The connecting means 117 is made of an aluminum cast product, includes an eccentric bearing 119 that supports the eccentric shaft 110, and connects the eccentric shaft 110 and the piston 132 via the piston pin 115. The end face of the cylinder bore 113 is sealed with a valve plate 139.

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

  FIG. 2 is a schematic diagram showing a cross section of the sliding portion A of FIG. 1, and FIG. 3 is a SIM image showing an example of a result of SIM (scanning ion microscope) observation of a film on a main shaft surface used in the embodiment. It shows.

  2 and 3, the crankshaft 108 uses gray cast iron (FC cast iron) as a base material 150, and has a hard coating on the surface of the main shaft 109 of the crankshaft 108. In this embodiment, an oxide coating 160 is formed. Further, on the surface of the oxide film 160, a soft film, that is, a resin film 170 in this embodiment is formed on the entire surface or a part thereof. The upper portion of the resin film 170 shown in FIG. 3 is a protective film for protecting the observation sample. First, the oxide film 160 will be described in detail.

  In FIG. 3, the oxide film 160 has, from the surface side, a first portion 151 including a first a portion 151 a and a first b portion 151 b having a microcrystalline structure and different crystal densities, and a vertically elongated portion below the first portion 151. A second portion 152 containing a columnar structure 156 is further provided, and a third portion 153 containing a horizontally elongated layered structure 157 further below the second portion 152. The lower portion of the third portion 153 is a substrate 150.

  In the first portion 151 formed on the outermost surface of the oxide film 160, the crystal density of the first a portion 151a on the outermost surface side is smaller than that of the first b portion 151b formed thereunder. I understand. The first a portion 151a includes a void portion 158 (corresponding to a blackish portion in FIG. 3) and a vertically elongated needle-like structure having a minor axis length of 100 nm or less and an aspect ratio of 1 to 10. 159 is contained. On the other hand, the first b portion 151b has a structure in which microcrystals 155 having a particle size of 100 nm or less are spread, and voids 158 and needle-like structures 159 as seen in the first a portion are almost observed. It turns out there is no.

In the first portion 151, as a result of performing EDS (energy dispersive X-ray spectroscopy) analysis or EELS (electron beam energy loss spectroscopy) analysis, the most occupying component is diiron trioxide (Fe ₂ O). ₃ ) shows that a silicon (Si) compound is also contained.

  The second portion 152 located below the first portion 151 has a vertical diameter of about 100 nm to 1 μm, a horizontal diameter of about 100 nm to 150 nm, and the vertical diameter is divided by the horizontal diameter. It can be seen that a so-called vertically long columnar structure 156 having a vertically long aspect ratio of about 3 to 10 is formed in the same direction.

In addition, according to the result of EDS and EELS analysis, the second portion 152 is composed of a portion containing silicon (Si) compound, in which the most occupying component is triiron tetroxide (Fe ₃ O ₄ ). I understand.

  Next, the third portion 153 located below the second portion 152 has a vertical diameter of several tens nm or less, a horizontal diameter of about several hundred nm, and a vertical diameter of the horizontal diameter. It can be seen that a so-called horizontally long layered structure 157 is formed which is long in the horizontal direction and whose aspect ratio is 0.01 to 0.1.

In the third portion 153, the result of the EDS or EELS analysis shows that the most occupying component is triiron tetroxide (Fe ₃ O ₄ ), which includes a silicon (Si) compound and a silicon (Si) solid solution part. It can be seen that it is composed of parts.

  The thickness of oxide film 160 in the present embodiment is about 3 μm.

  As described above, the oxide film 160 is composed of a first portion 151, a second portion 152, and a third portion 153 in order from the outermost surface. Not limited.

  The oxide film 160 may have a configuration including the above-described first portion 151, second portion 152, and third portion 153, and may include a portion having a composition other than these. Further, the oxide film 160 is not limited to the configuration in which the first portion 151, the second portion 152, and the third portion 153 are stacked in this order from the outermost surface. For example, other configurations of the oxide film 160 include a configuration in which the first portion 151 and the second portion 152 are stacked in this order from the outermost surface, a first portion 151 and a third portion 153 from the uppermost surface. Alternatively, a configuration in which the first portion 151 also exists between the first portion 151 and the second portion 152 and the third portion 153 from the outermost surface, or a single layer of the first portion 151 may be used. As described above, a configuration including other portions or a configuration in which the stacking order of each portion is different can be realized by adjusting various conditions.

  Typical conditions include a method of forming (forming) the oxide film 160. A known method of oxidizing an iron-based material can be suitably used for the method of manufacturing the oxide film 160, and is not particularly limited. The manufacturing conditions and the like can be set as appropriate according to the type of the iron-based material serving as the base material 150, its surface state (the above-described polishing finish and the like), and various conditions such as the physical properties of the oxide film 160 to be obtained. In the present disclosure, using a known oxidizing gas such as carbon dioxide (carbon dioxide gas) and a known oxidizing equipment, the gray cast iron which is the base material 122 within a range of several hundred degrees Celsius, for example, within a range of 400 to 800 ° C. Is oxidized, an oxide film 160 can be formed on the surface of the base material 15.

  Next, the resin film 170 will be described.

The resin film 170 is formed on the surface of the oxide film 160 and has a structure containing polyamideimide (PAI) as a binder and molybdenum disulfide (MoS ₂ ) particles (not shown) as a solid lubricant.

  Such a resin film 170 is formed by the following method.

First, preheating is performed to raise the temperature of the crankshaft 108 on which the oxide film 160 is formed to a predetermined temperature. This is intended to promote the adhesion of the resin film 170 to the surface of the oxide film 160.

  Next, while rotating the crankshaft 108 about the axis of the main shaft 109 as a center axis, a coating agent blended and adjusted for preparing the resin film 170 is applied by spraying. At the time of application, a masking jig having an appropriate shape is attached in order to prevent the coating agent from adhering to unnecessary places. After that, temporary drying is performed for several minutes at a temperature higher than the temperature at the time of preheating to cure the resin film 170.

  Further, the surface of the dried and cured resin film 170 is lightly buffed. This is for the purpose of finely adjusting the surface roughness of the outermost surface of the resin film 170, and a horse hair buff is more preferable than a nylon buff containing abrasive grains or a relatively hard steel buff.

  Finally, baking is performed at about 200 to 250 ° C. for about 30 minutes to about 2 hours to completely evaporate the diluent in the coating agent, thereby completely fixing the resin film 170 to the surface of the oxide film 160.

  In the present embodiment, with respect to the structure of the resin film 170, polyamideimide is used as a binder. However, the thermosetting resin is excellent in oil resistance, heat resistance, refrigerant resistance, and organic agent resistance. The same effect can be obtained by using an epoxy resin or a phenol resin.

  Further, in the present embodiment, molybdenum disulfide is used as the solid lubricant contained in resin film 170, but ethylene tetrafluoride resin (PTFE) and graphite (C) are used alone or as a mixture. The same effect can be obtained even if the same is performed.

Furthermore, when molybdenum disulfide or graphite is used as the solid lubricant, antimony trioxide (Sb ₂ O ₃ ) is used together with the antimony trioxide to capture air and oxygen that have entered the resin film 170. By being oxidized first, the solid lubricant in the resin film 170 is prevented from being deteriorated due to oxidation, and the effect of suppressing wear can be sufficiently exhibited.

  Next, comparison of hardness between sliding members will be described.

  Hardness is one of the mechanical properties of a substance or material, especially at or near the surface.When a material is liable to be deformed or scratched by a foreign substance, it is difficult to deform or damage the object. It is. There are various measurement means (definitions) and corresponding values (a measure of hardness) for hardness.

  If the sliding members are made of metal or non-ferrous metal, the coating on the surface of the sliding member is slid using the same indentation hardness test method (eg, nanoindentation method, Vickers or Rockwell hardness method). You may judge whether it is harder than a member.

  On the other hand, when it is difficult to use the indentation hardness test method such as the resin film 170 or the phosphate film of the present embodiment, it is desirable to make a determination by, for example, a ring-on-disk wear test. As an example of the evaluation method, a film is formed on the disk surface, and the disk is operated for about one hour in a state of being immersed in oil at a load of 1000 N, a rotation speed of 1 m / s, and the state of the sliding surface is observed. As a result, among the disks provided with the ring and the coating, it may be determined that the one that is relatively significantly worn has lower hardness.

  FIG. 4 is a characteristic diagram showing the hardness in the depth direction of the main shaft and the main bearing in the embodiment based on the above concept. In addition, hardness is shown by Vickers hardness.

  For measuring the hardness of the oxide film 160 on the surface of the main shaft 109, a nanoindentation device (tribo indenter) manufactured by Sienta Omicron Co., Ltd. was used. The hardness is measured by pressing the indenter for a certain period of time, then unloading it a little, and then pushing it in with a higher load than before 15 times, conducting a load-unloading test up to 1N. Then, the hardness of the oxide film 160 and the hardness distribution in the depth direction were measured.

  Since the hardness of the resin film 170 is significantly smaller than that of the main shaft 109 and the oxide film 160 and cannot be measured by the same apparatus, an estimation line of the hardness is calculated based on the result of the relative comparison by the wear test. This is indicated by a dotted line.

  The abrasion test was performed by the ring-on-disk method described above. The ring used in the test was made of the same material as the main bearing 111, while the disc was made of the same material as the crankshaft 108, and then a PAI resin having a film thickness of about 3 μm used in the present embodiment was used. Coated on the surface.

  As a result, while the wear amount of the ring was almost zero, the resin film on the disk surface was worn by about 1 to 2 μm. From this, it was determined that the resin film 170 was lower than the main bearing 111 in terms of the hardness index.

  On the other hand, regarding the Vickers hardness of the main bearing 111, a part of the inner peripheral surface of the main bearing 111 of the cylinder block 112 was cut out with a fine cutter, and the Vickers hardness was measured under the condition of a load of 0.5 kgf.

  From this result, it was found that an oxide film 160 having a hardness equal to or higher than that of the main bearing 111 as a mating sliding member was formed on the surface of the main shaft 109 constituting the journal bearing.

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

  Electric power supplied from a commercial power supply (not shown) is supplied to the electric element 106 via an external inverter drive circuit (not shown), and the electric element 106 is inverter-driven at a plurality of operating frequencies. The rotor 105 of the electric element 106 rotates the crankshaft 108, and the eccentric movement of the eccentric shaft 110 drives the piston 132 from the connecting means 117 via the piston pin 115. The piston 132 reciprocates in the cylinder bore 113, sucks the refrigerant gas 102 guided into the sealed container 101 through the suction tube (not shown) from the suction muffler 142, and compresses the refrigerant gas 102 in the compression chamber 134.

  The lubricating oil 103 is supplied to each sliding portion from an oil supply pump 120 with the rotation of the crankshaft 108, lubricates the sliding portion, and controls a seal between the piston 132 and the cylinder bore 113.

  Here, FIG. 5 shows a time-series change curve of the input of the refrigerant compressor and the COP in the embodiment.

  FIG. 5 (a) shows a time-series change of the compressor input over time, and FIG. 5 (b) shows a coefficient of performance COP (Coefficient of Performance) which is a coefficient used as a measure of energy consumption efficiency of a refrigerator or a refrigerator. (W) is a value obtained by dividing (W) by the input (W). For comparison, the results of the conventional refrigerant compressor are also shown.

  From FIG. 5 (a), the input immediately after the start of operation (hereinafter, referred to as an initial input) of both the refrigerant compressor of the present embodiment and the conventional refrigerant compressor is the highest, and thereafter, as the operation time elapses, It can be seen that the input gradually decreases and finally shows a substantially constant value (hereinafter, referred to as a steady input). Further, it can be seen that the refrigerant compressor of the present embodiment has a lower initial input than the conventional refrigerant compressor, and also has a reduced time to shift from the initial input to the steady input. Assuming that the transition time of the refrigerant compressor of the present embodiment is t1 and that of the conventional refrigerant compressor is t2, t1 is about 1/2 of t2. Thereby, as shown in FIG.5 (b), it turned out that COP is stabilized early and improves.

  Considering the results of FIG. 5, in the conventional refrigerant compressor, local contact occurs between the main shaft 109 and the main bearing 111 when the oil film thickness between the sliding members is reduced, particularly at a low speed operation (for example, 20 Hz or less). It is considered that the oil film breaks and the solid contact frequently occurs in the roughness region. In addition, since the oxide film 160 having high wear resistance (hard) is formed on the surface of the main shaft 109, the projections on the surfaces of the sliding members (main shaft and main bearing) do not wear away quickly, making it difficult to fit. Therefore, the time for solid contact is prolonged. Therefore, it is considered that the initial input is high and the time required to shift from the initial input to the steady input is also long.

  On the other hand, in the refrigerant compressor of the present embodiment, an oxide film 160 having a higher hardness than main bearing 111 is formed on the surface of main shaft 109, and a resin film 170 having a significantly lower hardness than main bearing 111 is formed on the surface. Due to the formation, even when the oil film thickness between the sliding members becomes extremely thin in the low-speed operation range and solid contact with the main bearing 111 occurs, the oil film is formed on the surface of the oxide film 160 which is a hard film. Due to the initial conformability of the resin film 170, which is a soft film, an input is low from the beginning of operation, and a highly efficient and highly reliable refrigerant compressor can be provided.

  Further, even if the oil film breaks during poor oil operation such as at the start of operation, molybdenum disulfide particles contained as a part of the resin film 170 on the surface of the main shaft 109 and as a solid lubricant are formed on the surface of the main bearing 111. Since the transfer and sliding are performed, the coefficient of friction can be reduced, and the efficiency of the refrigerant compressor can be increased.

Further, in the present embodiment, the hard film formed on the surface of the sliding member such as the main shaft 109 is the oxide film 160. The oxide film 160 is composed of microcrystals and the most occupied component is dioxide. Iron (Fe ₂ O ₃ ), a first portion 151 on the outermost surface that also contains a silicon (Si) compound, and a vertically occupied columnar structure underneath the first portion 151 are triiron tetroxide (Fe ₃ O ₄ ). A second portion 152 containing a silicon (Si) compound, and a layered structure below the second portion 152, and a silicon (Si) compound and a silicon (Si) solid solution portion containing triiron tetroxide (Fe ₃ O ₄ ). Therefore, not only the wear resistance is improved, but also the aggressiveness of the sliding member is reduced, and the adaptability at the initial stage of the sliding is also improved.

  Therefore, the resin film 170 is provided on a part of the oxide film 160, not on the entire surface, or is provided on the entire surface, and is partially worn out due to unevenness of the mating sliding member, and the oxide film 160 is Even if there is any contact, the operation of the oxide film 160 below the resin film 170 can be performed with low input from the initial operation and high efficiency operation can be realized, and the operation is highly reliable because of high wear resistance. Becomes possible.

  The high abrasion resistance of the oxide film 160, the reduction of the aggressiveness of the sliding member and the improvement of the conformability at the initial stage of sliding are described in Japanese Patent Application Nos. 2006-003910 and 2016-003909 of the present applicant. As described above, one of the reasons is considered as follows.

In other words, regarding the abrasion resistance, since the oxide film 160 is an oxide of iron, it is harder and chemically more stable than a conventional phosphate film, and moreover, it is harder than the outermost surface. Since the first portion 151 contains a silicon (Si) compound having a higher hardness than the oxide of iron, it is considered that the first portion 151 exhibits high wear resistance. Therefore, reliable operation is possible.

On the other hand, regarding the conformability, in the oxide film 160, the most occupied component of the first portion 151, which is the outermost surface, is diiron trioxide (Fe ₂ O ₃ ). The crystal structure of ₂ O ₃ ) is rhombohedral. The crystal structure of the rhombohedral crystal structure includes a cubic crystal structure of triiron tetroxide (Fe ₃ O ₄ ) located below the crystal structure, a close-packed hexagonal crystal, a face-centered cubic crystal, and a body-centered tetragonal crystal structure of a nitride film. It is more flexible in terms of crystal structure. Therefore, the first portion 151 containing a large amount of diiron trioxide (Fe ₂ O ₃ ) is compared with a conventional gas nitride film or a general oxide film (triiron tetroxide (Fe ₃ O ₄ ) single-part film). It is thought that while having a high hardness, the aggressiveness of the opponent is low, and the conformability at the beginning of sliding is improved. Therefore, even with the familiarity of the oxide film 160 itself, the input is low from the beginning of the operation and a highly efficient operation can be realized.

  That is, the oxide film 160 constituting the surface of the sliding member has a low input from the initial operation due to the conformability of the oxide film 160 itself, as well as the conformability effect of the resin film 170, and has high operation efficiency and reliability. High driving can be realized.

  Since the second portion 152 and the third portion 153 of the oxide film 160 both contain a silicon (Si) compound, the adhesion of the oxide film 160 including the first portion 151 to the substrate is strong. It will be. Moreover, the third portion 153 has a higher silicon content than the second portion 152. As described above, the portion containing the silicon (Si) compound is laminated, and the silicon content on the side in contact with the base material is large, so that the adhesion of the oxide film 160 is further enhanced. As a result, it is considered that the proof stress of the oxide film 160 is improved with respect to the load during sliding, and the wear resistance of the oxide film 160 is further increased. Then, even if the first portion 151, which is the outermost surface, is worn, the presence of the second portion 152 and the third portion 153 is presumed to exert more excellent wear resistance, and the reliability is improved.

  Further, from a different viewpoint, the high wear resistance of the oxide film 160, the reduction of the aggressiveness of the sliding member and the improvement of the conformability at the initial stage of the sliding are considered to be due to the following reasons.

  That is, regarding the abrasion resistance, the first portion 151 constituting the outermost surface of the oxide film 160 contains a silicon (Si) compound and has a fine microcrystalline structure as described above. Therefore, it is considered that the steel exhibits high wear resistance.

  On the other hand, regarding the conformability, the first portion 151 of the oxide film 160 has a microcrystalline structure as described above, and a slight void portion 158 is formed between the microcrystals. Or the surface has minute irregularities. Therefore, the lubricating oil 103 is easily held on the surface (sliding surface) of the oxide film 160 due to the capillary phenomenon. In other words, the presence of such small voids 158 and / or minute irregularities allows the lubricating oil 103 to be retained on the sliding surface even in a severe sliding state, that is, exhibits a so-called “oil retaining property”. It will be possible to do so.

  Further, the oxide film 160 has a columnar structure 156 (second portion 152) and a layered structure 157 (third portion 153) on the substrate 150 side below the first portion 151. Has relatively lower hardness (softer) than the microcrystal 155 of the first portion 151. Therefore, at the time of sliding, the columnar tissue 156 and the layered tissue 157 function like a "buffer" (the function of the "buffer" is only one of the second portion 152 and the third portion 153, and Therefore, the second portion 152 and / or the third portion 153 (preferably both) may be located below the first portion 151). Accordingly, it is considered that the microcrystal 155 on the outermost surface behaves so as to be compressed toward the base material 150 side by the pressure from the mating sliding member on the surface of the oxide film 160 during sliding. The aggressiveness is remarkably reduced as compared with other surface treatment films, and it is presumed that this leads to conformability.

  In other words, the oxide film 160 exhibits good adaptability from the low aggressiveness of the opponent and the “oil retention”, and therefore, as well as the adaptability effect of the resin film 170, the oxide film 160 itself also has an adaptability from the initial operation due to the adaptability. High efficiency operation with low input and highly reliable operation can be realized. Therefore, for example, even when the resin film 170 is worn and the oxide film 160 comes into contact with the other sliding member, the input is low from the beginning of the operation for a long period of time, so that the operation with high efficiency can be continued.

  As described above, by using the oxide film 160, it is possible to realize a high efficiency operation and a highly reliable operation with a low input from the initial operation in combination with the effect of the resin film 170 over a long period of time. However, the hard film formed on the sliding member of the present invention may be a film other than the oxide film 160 as long as it has at least the same hardness as the mating sliding member. is there.

  For example, if the base material 150 is an iron-based material, it may be a film formed by a method of impregnating carbon, nitrogen, or the like into the surface layer in addition to general quenching.

  Further, it may be a film formed by oxidation treatment using steam or dipping in an aqueous solution of sodium hydroxide.

  Furthermore, not only the film consisting of the compound layer formed by the above-mentioned oxidation, carburization, nitriding, oxidation treatment, etc., but also dislocation by cold working, work hardening, solid solution strengthening, precipitation strengthening, dispersion strengthening, grain refinement, etc. (Hereinafter, such a layer is referred to as a mechanical strength improving layer) in which the sliding motion is suppressed to strengthen the substrate.

  In addition, a layer formed by a coating method such as plating, thermal spraying, PVD, or CVD may be used.

  Therefore, in the present invention, such a compound layer, a mechanical strength improving layer, and a layer formed by a coating method are defined as a hard coating.

  And such a hard coating, that is, the compound layer, the mechanical strength improving layer, the layer formed by the coating method may be any one as long as it is harder than the mating sliding member. By providing a hard film and a soft film composed of at least one of a compound layer, a mechanical strength improving layer, and a layer formed by a coating method, a stable and highly efficient refrigerant compressor with low input from the initial operation is provided. can do.

  The base material on which the film is formed may be other than iron-based, as long as it can form a film having a hardness equal to or higher than that of the opposing main bearing 111.

  Further, in this embodiment, one kind of soft film is formed as one kind of film, but two or more kinds of plural layers may be used as long as the film is smaller in hardness than the mating sliding member. The effect is obtained.

  Further, in the present embodiment, an example in which the present invention is applied to a sliding portion between the main shaft 109 and the main bearing 111 has been described. However, this is a sliding portion between the eccentric shaft 110 and the eccentric bearing 119, or the piston 115 and the cylinder bore 112. Further, the hard coating 160 and the soft coating 170 may be provided on the sliding member on the bearing component side such as the main bearing instead of the shaft component side such as the main shaft, and the same effect can be obtained. Needless to say.

  In the present embodiment, a reciprocating (reciprocating) refrigerant compressor has been described as an example of a refrigerant compressor. It is needless to say that the same effect can be obtained also in the compressor described above.

  Furthermore, if the sliding member described in the present embodiment is exemplified by the one used in the refrigerant compressor, this is a component using the sliding member, a device such as a pump or a motor. It may be something, and there is no restriction on its application.

(Embodiment 2)
FIG. 6 is a schematic diagram illustrating a configuration of a refrigeration apparatus according to Embodiment 2 of the present invention. Here, only the outline of the basic configuration of the refrigeration apparatus will be described.

  In FIG. 6, the refrigeration apparatus has a heat-insulating box body with one side open, a main body 301 having a door body that opens and closes the opening, and a section that divides the inside of the main body 301 into a storage space 303 for articles and a machine room 305. A wall 307 and a refrigerant circuit 309 for cooling the inside of the storage space 303 are provided.

  The refrigerant circuit 309 is configured by connecting a refrigerant compressor 300, a radiator 313, a decompression device 315, and a heat absorber 317 in an annular pipe connection. The refrigerant compressor 300 is the refrigerant described in the first embodiment. There is as a compressor.

  The heat absorber 317 is arranged in the storage space 303 provided with a blower (not shown). The heat of cooling of the heat absorber 317 is agitated by a blower so as to circulate in the storage space 303 as indicated by an arrow, and the storage space 303 is cooled.

  In the refrigeration apparatus having the above-described configuration, by mounting the refrigerant compressor according to Embodiment 1 of the present invention as the refrigerant compressor 300, the power consumption of the refrigeration apparatus can be reduced, and energy saving can be achieved. Reliability can be improved. That is, the refrigerant compressor 300 forms the oxide film 160 having a hardness equal to or greater than that of the main bearing 111 on the surface of the main shaft 109, and forms the main surface on the entire surface or a part of the surface of the oxide film 160. Since the resin film 170 having a smaller hardness than the bearing 111 is formed, wear resistance between the shaft component and the bearing component is improved, and local contact sliding between the shaft component and the bearing component can be reduced. Improves reliability and performance. By improving the reliability and performance of the refrigerant compressor 300, the power consumption of the refrigeration apparatus can be reduced, energy saving can be realized, and the reliability of the refrigeration apparatus can be improved.

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

100, 300 Refrigerant compressor 101 Airtight container 103 Lubricating oil 106 Electric element 107 Compression element 109 Main shaft (sliding member)
111 Main bearing (sliding member)
160 Oxide film (hard film)
170 resin film (soft film)
309 Refrigerant circuit 313 Radiator 315 Pressure reducing device

Claims (5)

An electric element housed in a closed container, a compression element driven by the electric element to compress a refrigerant, a lubricating oil for lubricating between sliding members constituting the compression element, Refrigerant compression in which a hard film having a hardness equal to or greater than that of the sliding member is formed, and a soft film having a hardness smaller than that of the mating sliding member is formed on the entire surface or a part of the surface of the hard film. Machine. The refrigerant compressor according to claim 1, wherein the soft coating mainly comprises a resin. The refrigerant compressor according to claim 2, wherein the resin contains a solid lubricant. The refrigerant compressor according to any one of claims 1 to 3, wherein the electric element is inverter-driven at a plurality of operation frequencies including an operation frequency equal to or lower than a commercial power supply frequency. A refrigeration apparatus having a refrigerant circuit in which a refrigerant compressor, a radiator, a decompression device, and a heat absorber are connected in a ring by piping, wherein the refrigerant compressor is the refrigerant compressor according to any one of claims 1 to 4. .

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