Compressor, method for manufacturing compressor, and method for evaluating coating material for compressor

Abstract

A compressor (1) is provided with: a compression mechanism unit (13) that compresses a refrigerant; a motor for driving the compression mechanism part; and a housing that accommodates the compression mechanism part and the motor. The refrigerant compressed by the compression mechanism part (13) is discharged from the compressor (1) through a space inside the housing, and the compression mechanism part (13) is in a high-temperature atmosphere formed by the compressed refrigerant. An iron-based metal material is used as a base material of the case, and the nitrogen transmission rate of a coating film formed on the outer surface of the iron-based metal material is (a) 2500 [mol * [mu] m / (m2 * s * Pa)] or less at-40 DEG C, (b) 150 [mol * [mu] m / (m2 * s * Pa)] or less at normal temperature, and (c) 2500 [mol * [mu] m / (m2 * s * Pa)] or less at 100 DEG C.

Description

Technical Field

[0001] Embodiments of the present invention relate to a compressor, a method for manufacturing a compressor, and a method for evaluating a coating material for a compressor. Background Art

[0002] There is a so-called hermetic compressor in which a compression mechanism and an electric motor are housed in a hermetic casing.

[0003] In a hermetic compressor, after being compressed by the compression mechanism, the refrigerant passes through the space inside the hermetic shell and is discharged from the compressor via a discharge pipe such as a mirror plate provided in the hermetic shell. During operation of the compressor, the space inside the hermetic shell is filled with the compressed refrigerant, and the hermetic shell is heated by the compressed refrigerant.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Laid-Open No. 2020-153293 Summary of the Invention

[0007] Problems to be solved by the invention

[0008] In such compressors, when selecting the paint for coating the outer surface of the sealed casing, in order to ensure the rust-proof performance based on the paint, the main focus is on the close adhesion between the substrate and the coating film, and in reality, no special consideration is given to the air permeability of the coating film.

[0009] Here, in application to a refrigeration cycle device, the sealed casing is not only heated by the compressed refrigerant but also cooled by the low-temperature refrigerant returning from the evaporator, and the temperature is assumed to be lower than 0° C. depending on the location.

[0010] Therefore, when selecting the paint used for compressor coating, it is important to consider not only the adhesion between the substrate and the coating, but also the air permeability of the coating corresponding to the temperature, so that the penetration of air containing moisture can be effectively blocked under the actual operating environment of the compressor.

[0011] In view of such actual conditions, an object of the present invention is to provide a compressor with higher reliability by confirming the rust-proof performance of a coating through evaluation of the air permeability of a coating film.

[0012] Means for solving problems

[0013] A compressor according to one embodiment of the present invention comprises: a compression mechanism for compressing a refrigerant; an electric motor for driving the compression mechanism; and a housing for housing the compression mechanism and the electric motor. The refrigerant compressed by the compression mechanism is discharged from the compressor through a space inside the housing. The compression mechanism is exposed to a high-temperature atmosphere formed by the compressed refrigerant. The housing is made of an iron-based metal material, and the nitrogen permeability of the coating formed on the outer surface is (a) 2500 [mol·μm / (m 2 ·s·Pa)] or less, (b) at room temperature is 150[mol·μm / (m 2 ·s·Pa)] or less, and (c) 2500 [mol·μm / (m 2 ·s·Pa)] or less.

[0014] The nitrogen permeability of the coating film tends to increase not only in high-temperature environments but also in low-temperature environments relative to a reference temperature at or near room temperature. Based on this tendency, the nitrogen permeability of the coating film formed on the outer surface of the housing is (a) 2500 [mol·μm / m at -40°C. 2 ·s·Pa] or less, (b) 150[mol·μm / m at room temperature 2 ·s·Pa] or less, and (c) 2500 [mol·μm / m at 100°C 2 ·s·Pa] or less, so that the air permeability of the coating film is adapted to the actual operating environment of the compressor. This can provide a compressor that effectively suppresses the permeation of moisture and oxygen through the coating film throughout the entire housing, inhibiting the formation of rust in the housing and providing higher reliability.

[0015] Preferably, the compressor comprises: a low-pressure part, which is configured to introduce the refrigerant before being compressed by the compression mechanism part and is capable of separating the liquid refrigerant contained in the refrigerant; and a high-pressure part, which is formed separately from the low-pressure part and is connected to the low-pressure part in a manner capable of introducing the refrigerant after the liquid refrigerant is separated, the shell includes a first shell of the low-pressure part and a second shell of the high-pressure part, the compression mechanism part and the electric motor are accommodated in the second shell, and the coating is formed on the outer surface of at least one of the first shell and the second shell.

[0016] In this manner, by dividing (split) the compressor 1 into a low-pressure portion and a high-pressure portion, configuring the low-pressure portion to separate liquid refrigerant from the refrigerant, and housing the compression mechanism and electric motor in the high-pressure portion, it is possible to suppress the inflow of liquid refrigerant into the high-pressure portion, particularly the compression mechanism. In such a compressor, by forming a coating having the aforementioned specified gas permeability on at least one of the high-pressure portion and the low-pressure portion, it is possible to suppress not only the permeation of moisture and the like from areas heated by the compressed refrigerant but also from areas cooled by the refrigerant returning from the evaporator, thereby effectively suppressing the formation of rust in both the low-pressure portion and the high-pressure portion.

[0017] The coating film is preferably formed of an epoxy resin having a benzene ring in a part of a main chain of an amorphous molecular structure and in an additive.

[0018] Thus, by using a coating material in which an epoxy resin having a high crosslinking density is combined with benzene rings having a rigid molecular structure, it is possible to further reduce air permeability and promote further improvement in rust prevention performance by coating.

[0019] Another embodiment of the present invention provides a method for manufacturing a compressor, which is a method for manufacturing a compressor in which a compression mechanism for compressing a refrigerant and an electric motor for driving the compression mechanism are housed in a shell, wherein the method for manufacturing the compressor includes a paint selection process for selecting a paint for coating the outer surface of the shell, in which the gas permeability of a coating film based on the paint is measured at multiple temperatures including a first temperature less than 0°C, or the gas permeability represented by the coating film is obtained at the multiple temperatures, and a paint is selected whose gas permeability is within a range pre-set for each of the multiple temperatures.

[0020] In this way, during the paint selection process, by measuring the gas permeability of the coating film and performing a selection evaluation based on this gas permeability, it is possible to confirm the rust-preventive performance of the coating from the perspective of air permeability and select a more appropriate paint. Furthermore, by measuring the gas permeability at multiple temperatures, including a first temperature below 0°C, and evaluating the air permeability of the coating film, it is possible to perform the evaluation under conditions that simulate the actual operating environment of the compressor, thereby suppressing the formation of rust on the entire casing.

[0021] Preferably, in the paint selection step, the following paint is selected: the multiple temperatures include the first temperature and room temperature, the gas permeability is below a predetermined first threshold at the first temperature, and is below a predetermined second threshold lower than the first threshold at room temperature.

[0022] In this way, by measuring the gas permeability at a first temperature and at room temperature, and setting the second threshold value for comparison with the gas permeability at room temperature to be lower than the first threshold value for comparison with the gas permeability at the first temperature, changes in the gas permeability with temperature can be reflected in the selection and evaluation of the coating film, thereby enabling the selection of a more appropriate coating.

[0023] Preferably, the first temperature is not less than -40°C and not more than -20°C.

[0024] By setting the first temperature to a temperature between -40°C and -20°C in this manner, it is possible to perform a more appropriate evaluation based on the increasing tendency of the gas permeability with respect to a decrease in temperature and select an appropriate coating material.

[0025] Another embodiment of the present invention is a method for evaluating a compressor coating for coating a compressor that houses a compression mechanism for compressing a refrigerant and an electric motor for driving the compression mechanism in a shell, wherein a sample in which the coating is formed into a film is prepared, a gas permeability indicating the amount of gas passing through the sample per specified time is measured at multiple temperatures including a first temperature below 0°C, and performance evaluation of the coating film based on the coating is performed based on the gas permeability measured at the multiple temperatures.

[0026] By preparing a sample of a coating formed into a film and evaluating the coating's performance based on the sample's gas permeability, the rust-preventive performance of the coating can be confirmed and an appropriate coating can be selected using a relatively simple method. Furthermore, by measuring the gas permeability at multiple temperatures, including a first temperature below 0°C, and performing the performance evaluation, evaluation can be performed under conditions that simulate the actual operating environment of a compressor, enabling even more reliable performance evaluation.

[0027] Effects of the Invention

[0028] According to the present invention, the rust prevention performance of the coating can be appropriately evaluated from the viewpoint of air permeability, thereby providing a compressor with higher reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is a schematic diagram showing the configuration of a refrigeration cycle device including a compressor according to one embodiment of the present invention.

[0030] Figure 2 It is a cross-sectional view showing the structure of the above-mentioned compressor.

[0031] Figure 3 This is a flowchart showing the basic steps of the paint selection process.

[0032] Figure 4This is a schematic diagram schematically showing the structure of a coating film evaluation test device.

[0033] Figure 5 This is a schematic diagram showing test results of changes in differential pressure between the high temperature chamber and the low temperature chamber in the above-mentioned evaluation test apparatus in a high temperature range above room temperature.

[0034] Figure 6 This is a schematic diagram showing the test results of changes in the differential pressure between the high temperature chamber and the low temperature chamber in the above-mentioned evaluation test apparatus in a low temperature region below room temperature.

[0035] Figure 7 This is a schematic diagram showing the relationship between the nitrogen gas permeability of the coating film and the temperature. DETAILED DESCRIPTION

[0036] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

[0037] (Structure of Refrigeration Cycle Device)

[0038] Figure 1 Schematic diagram showing the configuration of a refrigeration cycle device C including a compressor 1 according to an embodiment of the present invention.

[0039] The refrigeration cycle device C is configured as an air conditioner and includes, in addition to a compressor 1, a four-way valve 2, an outdoor heat exchanger 3, an expansion valve 4, and an indoor heat exchanger 5. It also includes refrigerant pipes 6 (6a to 6f) connecting these refrigeration cycle elements 1 to 5. Refrigerant circulates through the refrigeration cycle device C via the refrigerant pipes 6. Examples of refrigerants applicable to this embodiment include R32, R410A, R448A, R449A, R404A, R407C, R454A, R454B, R454C, and R744.

[0040] The operation of the refrigeration cycle device C can be switched between cooling operation and heating operation by switching the flow path of the four-way valve 2 .

[0041] (Cooling operation)

[0042] During cooling operation, the refrigerant Figure 1 It circulates along the path indicated by the solid arrow A1.

[0043] Specifically, after the refrigerant comes out of the compressor 1, it flows through the refrigerant piping 6 in the order of the four-way valve 2, the outdoor heat exchanger 3, the expansion valve 4, and the indoor heat exchanger 5. The high-pressure gas refrigerant compressed by the compressor 1 is cooled and condensed by heat exchange with the outside air when passing through the outdoor heat exchanger 3. The outdoor heat exchanger 3 is equipped with an outdoor fan 3', which uses the outdoor fan 3' to blow outdoor air (i.e., outside air) into the interior. The pressure of the condensed gas-liquid mixed refrigerant drops when passing through the expansion valve 4, and it becomes a low-pressure liquid refrigerant and is supplied to the indoor heat exchanger 5. The liquid refrigerant flowing into the indoor heat exchanger 5 is heated and evaporated by heat exchange with the indoor air. The indoor heat exchanger 5 is equipped with an indoor fan 5', which uses the indoor fan 5' to blow indoor air into the interior. The evaporated gas-liquid mixed refrigerant then returns to the compressor 1 through the four-way valve 2.

[0044] (Heating operation)

[0045] During heating operation, the refrigerant Figure 1 Circulate in the path shown by the dotted arrow A2.

[0046] Specifically, after the refrigerant exits the compressor 1, it flows through the refrigerant piping 6 in the order of the four-way valve 2, the indoor heat exchanger 5, the expansion valve 4, and the outdoor heat exchanger 3. The high-pressure gas refrigerant compressed by the compressor 1 is cooled (i.e., releases heat to the indoor air) by heat exchange with the indoor air as it passes through the indoor heat exchanger 5, and condenses. The condensed gas-liquid mixed refrigerant drops in pressure as it passes through the expansion valve 4, becoming a low-pressure liquid refrigerant that is supplied to the outdoor heat exchanger 3. The liquid refrigerant that flows into the outdoor heat exchanger 3 is heated (i.e., absorbs heat from the outside air) by heat exchange with the outside air and evaporates. The evaporated gas-liquid mixed refrigerant then returns to the compressor 1 via the four-way valve 2.

[0047] (Defrost operation)

[0048] During heating operation, as the refrigerant evaporates in the outdoor heat exchanger 3, it removes heat from the outside air, causing water vapor in the outside air to condense into water droplets that adhere to the heat exchange components inside the outdoor heat exchanger 3. Due to the low temperature of the outside air, this adhered water may freeze and form frost. In this case, frost hinders heat exchange and may reduce heat exchange efficiency, so a defrost operation is performed to remove the frost.

[0049] During defrost operation, the four-way valve 2 is set to the same state as during cooling operation, allowing the refrigerant to circulate in the same order as during cooling operation. However, both the outdoor fan 3' and the indoor fan 5' are stopped, and the high-temperature, high-pressure gas refrigerant delivered from the compressor 1 heats the heat exchange components of the outdoor heat exchanger 3, thereby melting the frost. The dissolved water is then discharged from the outdoor heat exchanger 3 as drainage water.

[0050] (Compressor Structure)

[0051] Figure 2 It is a cross-sectional view showing the internal structure of the compressor 1 according to the present embodiment.

[0052] The compressor 1 includes a compressor body 1a and an accumulator 1b. The accumulator 1b includes an intake pipe 21, through which the refrigerant flowing out of the heat exchanger operating as an evaporator is supplied to the accumulator 1b. The evaporator corresponds to the indoor heat exchanger 5 during cooling operation or the outdoor heat exchanger 3 during heating operation. The accumulator 1b separates the supplied refrigerant into gas and liquid, and supplies the refrigerant after the liquid refrigerant is separated (i.e., gas refrigerant) to the compressor body 1a. In this way, the compressor 1 is divided into the compressor body 1a and the accumulator 1b, and the compressor body 1a and the accumulator 1b are connected to each other via the refrigerant inlet pipe 22. Here, the compressor body 1a constitutes the "high-pressure part" of the compressor 1, and the accumulator 1b constitutes the "low-pressure part" of the compressor 1. In addition, the sealed shell 11 of the compressor body 1a corresponds to the "first shell", and the shell of the accumulator 1b corresponds to the "second shell".

[0053] In the present embodiment, the compressor 1 is a sealed rotary compressor. The compressor 1, specifically the compressor body 1a, includes a sealed shell 11, and an electric motor (hereinafter referred to as "motor") 12 and a compression mechanism 13 as a power source are housed inside the sealed shell 11. The motor 12 and the compression mechanism 13 are connected via a drive shaft 14, and the rotational driving force of the motor 12 is transmitted to the compression mechanism 13 via the drive shaft 14, thereby driving the compression mechanism 13. Electricity is supplied to the motor 12 from an external power source via a sealed terminal 15. The drive shaft 14 is supported by a plurality of bearings, in the present embodiment, by a main bearing 16a and a sub-bearing 16b so as to be rotatable relative to the sealed shell 11.

[0054] The sealed shell 11 is cylindrical in shape as a whole. The sealed shell 11 is a structure in which the upper and lower ends of the cylindrical shell body 11a, which is open at the top and bottom, are respectively closed by hemispherical mirror plates 11b and 11c. The shell body 11a and the mirror plate 11c on the lower side can be formed integrally. A refrigerant inlet pipe 22 extending from the liquid accumulator 1b is connected to the shell body 11a, and the gas refrigerant separated by the liquid accumulator 1b is introduced into the interior of the sealed shell 11 through the refrigerant inlet pipe 22. The gas refrigerant compressed by the compression mechanism 13 passes through the space S inside the sealed shell 11, specifically, through the gap in the entire interior of the sealed shell 11 except for the space occupied by the motor 12, the compression mechanism 13, the drive shaft 14, etc., and is discharged to the outside of the sealed shell 11 through the discharge pipe 23 installed on the mirror plate 11b on the upper side.

[0055] Inside the sealed casing 11 , the electric motor 12 is housed in the upper half of the casing body 11 a , and the compression mechanism 12 is housed in the lower half of the casing body 11 a .

[0056] The motor 12 includes a stator 121 fixed to the housing body 11a, and a rotor 122 disposed within the inner diameter portion of the stator 121 and fixed to the drive shaft 14. The rotor 122 is rotatable integrally with the stator 121 and the drive shaft 14. The motor 12 is a permanent magnet synchronous motor, with coils formed in the stator 121 and permanent magnets mounted or embedded in the rotor 122. By applying current to the coils, the rotor 122 rotates, driving the compression mechanism 13 via the drive shaft 14.

[0057] The compression mechanism 13 is disposed between the main bearing 16a and the auxiliary bearing 16b. In this embodiment, the compression mechanism 13 comprises a single-stage compression mechanism, which is composed of a cylinder 131, an eccentric portion 141 of the drive shaft 14, and a rotary piston 132. The number of stages of the compression mechanism is not limited to a single stage and may also be multiple.

[0058] The cylinder body 131 defines a cylinder chamber, and the annular rotary piston 132 is housed in the cylinder chamber together with the eccentric portion 141 in a clearance fit with the eccentric portion 141. The inner diameter of the cylinder body 131 is larger than the outer diameter of the rotary piston 132, forming a gap between the cylinder body 131 and the rotary piston 132.

[0059] The cylinder 131 has a vane groove extending radially from the inner periphery of the cylinder 131. The sliding vane 133 is inserted into the vane groove. A spring 134 is interposed in a compressed state between the cylinder 131 and the sliding vane 133. The sliding vane 133 is pressed against the outer periphery of the rotary piston 132 by the spring 134.

[0060] The gap between the cylinder 131 and the rotary piston 132 is divided into two spaces, a suction chamber and a compression chamber, by the sliding vane 133. The suction chamber and the compression chamber of the compression mechanism 13 are sealed by the main bearing 16a arranged on the upper side and the auxiliary bearing 16b arranged on the lower side.

[0061] The cylinder 131 has a suction port formed on its inner circumference and connected to the suction chamber. The refrigerant introduction pipe 22 extending from the accumulator 1b is inserted and connected to the suction port. As a result, the refrigerant flowing out of the accumulator 1b is introduced from the refrigerant introduction pipe 22 into the suction chamber via the suction port.

[0062] Lubricating oil is enclosed in the sealed housing 11, and the compression mechanism 13 is mostly immersed in the lubricating oil. Examples of circulating oil applicable to this embodiment include polyol ester lubricating oil to which 0.5% by mass of glycidyl epoxy and 0.1% by mass of a phenolic antioxidant are added.

[0063] The base materials of the compressor 1's housing, specifically the sealed housing 11 of the compressor body 1a and the housing of the accumulator 1b, are all made of iron-based metal materials. Examples of materials that can be used as the base materials for these housings include steel plates, specifically hot-rolled steel plates (SPHE materials). In this embodiment, SPHE-P materials are used. Furthermore, the base materials of the housings are subjected to an appropriate plating treatment, such as electrogalvanizing, for the purpose of protecting against rust, and then painted on their outer surfaces to form a coating film. In actual practice regarding the coating of the compressor 1, the selection of the paint used to coat the outer surface of the sealed housing 11 primarily focuses on the close adhesion between the base material and the coating film, with no particular consideration given to the air permeability of the coating film.

[0064] During operation of the compressor 1, the space inside the sealed housing 11 is filled with compressed refrigerant, heating the sealed housing 11. Meanwhile, the housing of the accumulator 1b is assumed to be cooled to below 0°C by the relatively low-temperature refrigerant returning from the evaporator. The same is true for the housing of the compressor body 1a, i.e., the sealed housing 11. It is assumed that the joint connecting the refrigerant inlet pipe 22 and its surrounding areas are cooled to below 0°C.

[0065] Therefore, in selecting the paint used for coating the compressor 1, not only the close adhesion between the substrate and the coating is considered, but in this embodiment, in the selection of the paint, the air permeability of the coating corresponding to the temperature is also considered in the order shown below, so as to effectively suppress the penetration of air containing moisture in the actual operating environment of the compressor 1. In other words, in addition to the normal environment at room temperature, the necessary gas barrier properties are ensured in both the heating environment of the compressed refrigerant and the cooling environment of the refrigerant returning from the evaporator.

[0066] (Description of the coating selection process)

[0067] Figure 3 This is a flowchart showing the basic steps of the coating material selection process according to this embodiment.

[0068] Figure 4 It is a schematic diagram schematically showing the structure of a coating film evaluation test apparatus 101 .

[0069] While making appropriate reference Figure 4 , mainly through Figure 3 A description will be given of a process for selecting a coating film that can be used in manufacturing the compressor 1 according to the present embodiment.

[0070] The coating selection process of this embodiment includes a step of measuring the nitrogen permeability R of the coating. While the coating is intended to prevent the transmission of oxygen and moisture in the air, nitrogen is used as the measurement gas because a correlation has been observed between the permeability of oxygen and moisture and nitrogen. The nitrogen permeability R is measured using a method based on Japanese Industrial Standard (JIS) K 7126-1 or International Organization for Standardization (ISO) standard 15105-2, specifically using the differential pressure method specified in JIS K 7126-1.

[0071] In S201 , a coating film sample F is produced or prepared and placed in the evaluation test apparatus 101 .

[0072] Sample F is prepared by forming the paint into a film of a predetermined thickness (e.g., 130 μm). Specifically, the paint to be tested is sintered on a mold of an appropriate shape coated with a releasing agent. Only the film is then released from the mold. The paint is then applied a desired number of times onto the released film to produce Sample F of the predetermined thickness. The paint is sintered during film formation because the coating process is sintered during mass production.

[0073] like Figure 4 As shown, the evaluation test apparatus 101 includes a container 111 that can be divided into an upper half 111a and a lower half 111b. The interior of container 111 is divided into a high-pressure space (hereinafter referred to as the "high-pressure chamber") Ca and a low-pressure space (hereinafter referred to as the "low-pressure chamber") Cb by a sample F held between the upper half 111a and the lower half 111b. Specifically, in this embodiment, the interior of the upper half 111a forms the high-pressure chamber Ca, and the interior of the lower half 111b forms the low-pressure chamber Cb. An appropriate sealing material 201, such as an O-ring, is interposed between the sample F and the upper half 111a.

[0074] A first vacuum / gas inlet port ha is formed in the upper portion 111a, extending through the upper portion 111a. A second vacuum / gas inlet port hb is formed in the lower portion 111b, extending through the lower portion 111b. The first vacuum / gas inlet port ha allows residual gas to be exhausted from the high-pressure chamber Ca and a predetermined test gas to be introduced. Conversely, the second vacuum / gas inlet port hb allows residual gas to be exhausted from the low-pressure chamber Cb and a predetermined test gas to be introduced. Specifically, a vacuum pump and a first gas supply are connected to the high-pressure chamber Ca via the first vacuum / gas inlet port ha, while a vacuum pump and a second gas supply are connected to the low-pressure chamber Cb via the second vacuum / gas inlet port hb. In this embodiment, nitrogen is used as the test gas. Pressure sensors 301a and 301a, respectively, are connected to the upper portion 111a and the lower portion 111b, respectively, to detect the pressures Pa and Pb in the high-pressure chamber Ca and the low-pressure chamber Cb.

[0075] In S202, the residual gas is sucked from both the high-pressure chamber Ca and the low-pressure chamber Cb, and each chamber Ca and Cb is evacuated. This removes the dissolved gas from the sample F and discharges it from each chamber Ca and Cb together with the residual gas.

[0076] In S203 , nitrogen gas is introduced into the high-pressure chamber Ca and the low-pressure chamber Cb until the pressure reaches atmospheric pressure.

[0077] In S204, a differential pressure Pd is established between the high-pressure chamber Ca and the low-pressure chamber Cb. Specifically, after the pressures in chambers Ca and Cb reach atmospheric pressure, nitrogen gas is further introduced into the high-pressure chamber Ca. In this embodiment, the differential pressure Pd is set to 0.020 [MPa]. The differential pressure Pd can be appropriately set within a range that does not cause deformation of the sample F placed in the apparatus 101.

[0078] In addition to the above, the differential pressure Pd can be formed by, after evacuating each chamber Ca, Cb, introducing nitrogen gas into the high-pressure chamber Ca until the pressure reaches a predetermined value (0.020 [MPa] in this embodiment).

[0079] In S205, the pressure change in the high-pressure chamber Ca is monitored over a predetermined period of time. In this embodiment, the pressure change is monitored for approximately 10 hours. Nitrogen gas permeates through the sample F from the high-pressure chamber Ca to the low-pressure chamber Cb, causing the pressure in the high-pressure chamber Ca to decrease. By maintaining the pressure in the low-pressure chamber Cb at atmospheric pressure, the pressure change in the high-pressure chamber Ca represents the change in the differential pressure Pd between the high-pressure chamber Ca and the low-pressure chamber Cb.

[0080] In S206 , the nitrogen permeability R of the sample F is calculated based on the change in the pressure in the high pressure chamber Ca, that is, the change in the differential pressure Pd between the high pressure chamber Ca and the low pressure chamber Cb. The nitrogen permeability R is calculated based on the following formula.

[0081] μ={Vc / (R×T×Pu×A)}×dP / dt…(1)

[0082] Q=μ×h…(2)

[0083] The above formula (1) is the air permeability [mol / (m 2 ·s·Pa)], the above formula (2) is the formula for the air permeability coefficient [mol·μm / (m 2 ·s·Pa)]. Vc represents the volume of the high-pressure chamber Ca [m 3 ], R represents the gas constant, T represents the test temperature [K], Pu represents the differential pressure [Pa], A represents the gas permeation area [m 2 ], dP / dt represents the pressure change [Pa / s]. Furthermore, h represents the thickness of sample F [μm]. In this embodiment, the nitrogen gas permeability coefficient Q is used as the nitrogen gas permeability R, and the performance of the coating film is evaluated from the perspective of nitrogen gas permeability. As described above, even when the low-pressure chamber Cb is maintained in a vacuum state and nitrogen gas at a predetermined pressure is introduced into the high-pressure chamber Ca, the pressure change in the low-pressure chamber Cb can be monitored and the nitrogen gas permeability R can be calculated based on the pressure in the low-pressure chamber Cb.

[0084] In this embodiment, a plurality of test temperatures T including a temperature below 0°C are tested. Figure 3 The process is shown in the flowchart. In this embodiment, the test temperature T is -40°C, -20°C, -10°C, 0°C, 25°C, 40°C, 50°C, 70°C, and 106°C. Furthermore, in this embodiment, the coating material uses an epoxy resin having benzene rings in part of the main chain of the amorphous molecular structure and in the additive. Here, 25°C is considered normal temperature, and 106°C corresponds to the glass transition temperature of the coating film formed by the epoxy resin.

[0085] Figure 5 This is a schematic diagram showing test results of changes in the differential pressure Pd between the high temperature chamber Ca and the low temperature chamber Cb in the evaluation test apparatus 101 for test temperatures T above room temperature.

[0086] In this figure, the horizontal axis represents time t, and the vertical axis represents differential pressure Pd. The thick solid line La represents differential pressure Pd at a test temperature Tr = 25°C, the dotted line Lb represents differential pressure Pd at a test temperature Tp1 = 40°C, the double-dashed line Lc represents differential pressure Pd at a test temperature Tp2 = 50°C, the long-dashed line Ld represents differential pressure Pd at a test temperature Tp3 = 70°C, and the single-dashed line Le represents differential pressure Pd at a test temperature Tp4 = 106°C.

[0087] Under high-temperature conditions above room temperature Tr, the differential pressure Pd remains roughly the same at room temperature Tr and Tp1 = 40°C, or even slightly decreases at Tp1 = 40°C. This indicates that the nitrogen permeability R does not change significantly at room temperature Tr and Tp1 = 40°C. In contrast, at Tp2 = 50°C, the differential pressure Pd decreases significantly compared to Tp1 = 40°C, and the nitrogen permeability R shifts to an increasing trend during the temperature increase from Tp1 = 40°C to Tp2 = 50°C. At Tp2 = 50°C and Tp3 = 70°C, the differential pressure Pd barely changes. At Tp4 = 106°C, the glass transition temperature, the differential pressure Pd decreases again, resulting in a sharp increase in the nitrogen permeability R.

[0088] Figure 6 This is a schematic diagram showing test results of changes in the differential pressure Pd between the high temperature chamber Ca and the low temperature chamber Cb in the evaluation test apparatus 101 for test temperatures T below room temperature.

[0089] In this figure, the horizontal axis represents time t, and the vertical axis represents differential pressure Pd. The thick solid line La represents the differential pressure Pd at a test temperature Tr = 25°C, the dashed line Lf represents the differential pressure Pd at a test temperature Tn1 = 0°C, the two-dot chain line Lg represents the differential pressure Pd at a test temperature Tn2 = -10°C, the long dashed line Lh represents the differential pressure Pd at a test temperature Tn3 = -20°C, and the single-dot chain line Li represents the differential pressure Pd at a test temperature Tn4 = -40°C.

[0090] Under low-temperature conditions below room temperature Tr, from room temperature Tr = 25°C to Tn2 = -10°C, the lower the test temperature T, the slower the decrease in differential pressure Pd. This indicates that the nitrogen permeability R continues to decrease until at least Tn2 = -10°C. In contrast, at Tn3 = -20°C, the differential pressure Pd decreases compared to the case of room temperature Tr = 25°C. As the temperature decreases from Tn2 = -10°C to Tn3 = -20°C, the nitrogen permeability R shifts to an increasing trend. Furthermore, at Tn4 = -40°C, the differential pressure Pd decreases sharply, indicating a sharp increase in the nitrogen permeability R.

[0091] Figure 7 This is a schematic diagram showing the relationship between the nitrogen gas permeability R of the coating film and the temperature T. The horizontal axis represents the temperature T, and the vertical axis represents the nitrogen gas permeability R.

[0092] according to Figure 4 and Figure 5The experimental results shown show that the nitrogen gas permeability R reaches its lowest value at room temperature Tr = 25°C or at a temperature close to it, Tn1 = 0°C, and increases as the temperature T rises from around Tp1 = 40°C to Tp4 = 106°C. On the other hand, the nitrogen gas permeability R begins to increase below Tn2 = -10°C and increases further as the temperature T decreases toward Tn4 = -40°C. Figure 7 Based on these results, the relationship between the temperature T and the nitrogen permeability R is schematically represented and organized into a diagram showing a rough relationship.

[0093] In this embodiment, as the temperature T for evaluating the nitrogen gas permeability R of the coating film, a plurality of temperatures T1 to T3, including T1 below 0°C, are used. Specifically, assuming the actual operating environment of the compressor 1 in the refrigeration cycle device C, T1 = -40°C, T2 = 25°C, and T3 = 100°C are used. T1 = -40°C is a temperature that simulates the cooling environment of the refrigerant returning from the evaporator, T2 = 25°C is a temperature that simulates a normal state at room temperature, and T3 = 100°C is a temperature that simulates the heating environment of the compressed refrigerant. The temperatures T1 to T3 can be appropriately set according to the actual operating environment of the compressor 1, that is, the temperature that the refrigerant can achieve during the operation of the compressor 1. Here, the temperature T1 corresponds to the "first temperature" of this embodiment.

[0094] Then, in Figure 3 In S206 of the flowchart shown in FIG. 1 , the nitrogen permeability R is measured at the test temperatures T1 = -40°C, T2 = 25°C, and T3 = 100°C, respectively, to evaluate the performance of the coating film. Specifically, (a) the nitrogen permeability R at T1 = -40°C is 2500 [mol·μm / (m 2 ·s·Pa)] or less, (b) the nitrogen permeability R at T2 = 25°C is 150 [mol·μm / (m 2 ·s·Pa)] or less and (c) the nitrogen permeability R at T3 = 100°C is 2500 [mol·μm / (m 2 ·s·Pa)], and the paint of this sample was selected as the paint used for painting the compressor 1. Here, R=2500[mol·μm / (m 2 ·s·Pa)] corresponds to the "first threshold value" of the gas permeability in this embodiment, R = 150 [mol·μm / (m 2 ·s·Pa)] corresponds to the “second threshold value” of the gas permeability in this embodiment.

[0095] After selecting the paint, the compressor 1 is coated by powder coating. Specifically, the outer surface of the sealed housing of the compressor body 1a and the outer surface of the housing of the accumulator 1b are coated, and the compressor 1 is assembled. The assembly process after coating can be carried out in the same way as before.

[0096] (Explanation of the effects)

[0097] In this embodiment, the nitrogen permeability R(a) of the coating formed on the housing of the compressor 1, specifically, on the outer surfaces of the compressor body 1a and the accumulator 1b, is 2500 [mol·μm / m 2 ·s·Pa] or less, (b) 150[mol·μm / m at room temperature 2 ·s·Pa] or less, and (c) 2500 [mol·μm / m at 100°C 2 ·s·Pa] or less, thereby effectively suppressing the permeation of moisture and oxygen through the coating film under the actual operating environment of the compressor 1, suppressing the generation of rust in the base material of the iron-based metal material throughout the entire housing, and providing a more reliable compressor 1.

[0098] The compressor 1 is divided into a low-pressure portion (liquid reservoir 1b) and a high-pressure portion (compressor body 1a). A coating having the above-specified nitrogen permeability R is formed on at least one of the housing of the low-pressure portion, i.e., the housing of the liquid reservoir 1b, and the housing of the high-pressure portion, i.e., the sealed housing 11 of the compressor body 1a. This effectively suppresses not only the permeation of moisture and the like from areas heated by the compressed refrigerant, but also the permeation from areas cooled by the refrigerant returning from the evaporator, thereby suppressing the formation of rust in both the low-pressure portion and the high-pressure portion.

[0099] As a specific coating material, by using a coating material in which an epoxy resin having a high crosslinking density is combined with benzene rings having a rigid molecular structure, it is possible to further reduce air permeability and promote further improvement in the rust prevention performance of the coating.

[0100] When selecting a coating for use in the compressor 1 casing, measuring the gas permeability of the coating film and conducting a performance evaluation based on this measurement allows confirmation of the coating film's rust-proof performance from the perspective of air permeability, allowing for the selection of a more appropriate coating. Using nitrogen as the test gas allows for correlation with the actual permeability of oxygen and moisture, the targets of the coating, allowing for safe and appropriate performance evaluation.

[0101] Furthermore, by measuring the gas permeability at multiple temperatures, including temperatures below 0°C (the first temperature), and evaluating the gas permeability of the coating, the evaluation can be performed under conditions that simulate the actual operating environment of the compressor 1, thereby suppressing the formation of rust in the casing of the entire compressor 1. By evaluating the adhesion between the substrate and the coating in conjunction with the gas permeability, further improvements in the performance of the coating can be achieved.

[0102] By measuring the gas permeability at a first temperature and at room temperature, and setting a second threshold value for comparison with the gas permeability at room temperature to be lower than the first threshold value for comparison with the gas permeability at the first temperature, changes in the gas permeability with temperature can be reflected in the performance evaluation of the coating film, enabling the selection of a more appropriate coating.

[0103] By setting the first temperature to a temperature of -40°C or higher and -20°C or lower, a more appropriate evaluation based on the increasing tendency of the gas permeability, specifically, the nitrogen permeability R, with respect to a temperature decrease can be performed.

[0104] Furthermore, by preparing a sample F in which the paint is formed into a film, and evaluating the performance of the paint based on the gas permeability of the sample F, the rust prevention performance of the coating can be confirmed by a relatively simple method, and an appropriate paint can be selected.

[0105] While several embodiments of the present invention have been described, these embodiments are provided as examples and are not intended to limit the scope of the invention. These novel embodiments may be implemented in various other ways, and various omissions, substitutions, and modifications may be made without departing from the spirit of the invention. These embodiments and their variations are intended to be included within the scope and spirit of the invention, and are intended to be included within the invention set forth in the claims and their equivalents.

[0106] Description of Reference Numerals

[0107] C...Refrigeration cycle device, 1...Compressor, 1a...Compressor body, 1b...Accumulator, 11...Sealed casing, 11a...Casing body, 11b, 11c...Mirror plate, 12...Motor, 121...Stator, 122...Rotor, 13...Compression mechanism, 131...Cylinder, 132...Rotary piston, 133...Sliding vane, 134...Spring, 14...Drive shaft, 15...Sealed terminal, 16a...Main bearing, 16b...Auxiliary bearing, 21...Suction pipe, 22...Discharge pipe, 23...Refrigerant inlet pipe, 2...Four-way valve, 3...Outdoor heat exchanger, 3'...Outdoor fan, 4...Expansion valve, 5...Indoor heat exchanger, 5'...Indoor fan, 6 (6a to 6f)...Refrigerant piping, S...Space inside the sealed casing.

Claims

1. A compressor comprising: The compression mechanism compresses the refrigerant; an electric motor that drives the compression mechanism; and a housing for accommodating the compression mechanism and the electric motor; The refrigerant compressed by the compression mechanism is discharged from the compressor through the space inside the shell. The compression mechanism is exposed to a high-temperature atmosphere formed by the compressed refrigerant. in, The base material of the shell is made of iron-based metal material. The nitrogen permeability of the coating film formed on the outer surface is (a) 2500 [mol·μm / (m 2 ·s·Pa)] or less, (b) at room temperature is 150[mol·μm / (m 2 ·s·Pa)] or less, and (c) 2500 [mol·μm / (m 2 ·s·Pa)] or less.

2. The compressor according to claim 1, wherein The compressor comprises: a low-pressure portion configured to introduce refrigerant before compression by the compression mechanism portion and to separate liquid refrigerant contained in the refrigerant; and The high-pressure portion is formed separately from the low-pressure portion and is connected to the low-pressure portion in a manner capable of introducing the refrigerant after the liquid refrigerant is separated. The housing includes a first housing for the low-pressure portion and a second housing for the high-pressure portion, and the compression mechanism and the motor are housed in the second housing. The coating film is formed on the outer surface of at least one of the first housing and the second housing.

3. The compressor according to claim 1 or 2, wherein: The coating film is formed of an epoxy resin having a benzene ring in a part of a main chain of an amorphous molecular structure and in an additive.

4. A method for manufacturing a compressor, wherein a compressor housing a compression mechanism for compressing a refrigerant and a motor for driving the compression mechanism is housed in a housing, wherein: The compressor manufacturing method includes a paint selection step of selecting a paint to be applied to the outer surface of the housing. In the coating selection process, The gas permeability of the coating film made of the coating material is measured at a plurality of temperatures including a first temperature lower than 0° C., or the gas permeability of the coating film is obtained at the plurality of temperatures. The coating material having the gas permeability within a range preset for each of the plurality of temperatures is selected.

5. The method for manufacturing a compressor according to claim 4, wherein: In the coating selection process, the following coatings are selected: The multiple temperatures include the first temperature and normal temperature, The gas permeability is equal to or lower than a predetermined first threshold value at the first temperature, and is equal to or lower than a predetermined second threshold value lower than the first threshold value at room temperature.

6. The method for manufacturing a compressor according to claim 5, wherein: The first temperature is a temperature not less than -40°C and not more than -20°C.

7. A method for evaluating a coating for a compressor, wherein the coating is used for coating a compressor having a housing containing a compression mechanism for compressing a refrigerant and a motor for driving the compression mechanism, wherein: Prepare a sample in which the coating is formed into a film. measuring a gas permeability indicating the amount of gas permeating the sample per predetermined time at a plurality of temperatures including a first temperature lower than 0° C., Performance evaluation of the coating film formed by the coating material is performed based on the gas permeability measured at each of the plurality of temperatures.

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