Method for manufacturing compressor, and compressor

Abstract

To inspect, in the manufacturing process of a compressor, the state of fixation of a stator to a body without disassembling the compressor.SOLUTION: In a method for manufacturing a compressor, a fixing step, a measuring step, and a determining step are performed. In the fixing step, an assembly (70) is formed. In the assembly (70), a stator (50) is fixed to a body (16), and an insulating layer (56a) is put in between the body (16) and a core (51). In the measuring step, the electrical characteristics between a coil (57) and the body (16) in the assembly (70) are measured. In the determining step, it is determined whether the state of fixation of the stator (50) to the body (16) is good or bad on the basis of the thickness of the insulating layer (56a) estimated using the electrical characteristics of the assembly (70).SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present disclosure relates to a method for manufacturing a compressor and a compressor manufactured by the method. [Background technology]

[0002] In the compressor disclosed in Patent Document 1, a resin member is sandwiched between the casing body and the stator core. The resin member electrically insulates the casing body from the stator core. By electrically insulating the casing body from the stator core, this compressor aims to reduce electromagnetic noise caused by adjusting the rotational speed of the electric motor with an inverter device. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2023-067377 Summary of the Invention [Problem to be solved by the invention]

[0004] The manufacturing process for the compressor disclosed in Patent Document 1 includes a shrink fitting process in which a stator is fixed to a body of a casing by shrink fitting. In this shrink fitting process, a stator having a resin member attached to a core is inserted into a body whose inner diameter has been expanded by heating, and the body is cooled to reduce the inner diameter of the body, thereby fixing the stator to the body.

[0005] During the shrink fitting process, there is a risk that the resin member will melt when it comes into contact with the high-temperature body. If the resin member melts, it may flow as the inner diameter of the body shrinks, and the body may not be able to obtain sufficient holding force to hold the stator.

[0006] An object of the present disclosure is to inspect the state of fixation of the stator to the body without disassembling the compressor in a method of manufacturing a compressor in which the stator core is fixed to the body of a casing by shrink fitting. [Means for solving the problem]

[0007] A first aspect of the present disclosure is a method for manufacturing a compressor (10) in which a compression mechanism (30) and an electric motor (40) that drives the compression mechanism (30) are housed inside a casing (15) having a cylindrical metal body (16), and the stator (50) of the electric motor (40) has a core (51), a coil (57), and an insulating layer (56a) that covers an outer surface of the core (51), the method comprising: fixing the stator (50) to the body (16) by shrink fitting; and sandwiching the insulating layer (56a) between an inner surface of the body (16) and an outer surface of the core (51). The method includes a fixing step of forming an assembly (70) in which the body (16) and the stator (50) are combined in a fixed state; a measuring step of measuring electrical characteristics between the coil (57) and the body (16) in the assembly (70); and a judging step of estimating the thickness of the insulating layer (56a) in the assembly (70) based on the electrical characteristics of the assembly (70) measured in the measuring step, and judging whether the fixed state of the stator (50) to the body (16) is good or bad based on the estimated thickness of the insulating layer (56a).

[0008] In a first aspect, a method for manufacturing a compressor (10) includes a fixing step, a measuring step, and an evaluation step. In the assembly (70) formed in the fixing step, an insulating layer (56a) is sandwiched between the inner surface of the body (16) of the casing (15) and the outer surface of the core (51) of the stator (50). In the measuring step, electrical characteristics between the coil (57) and the body (16) in the assembly (70) are measured.

[0009] The electrical characteristics between the coil 57 and the body 16 in the assembly 70 vary depending on the thickness of the insulating layer 56a. Therefore, in the determining step, the thickness of the insulating layer 56a in the assembly 70 is estimated based on the electrical characteristics of the assembly 70 measured in the measuring step. Furthermore, if the thickness of the insulating layer 56a in the assembly 70 changes, the interference in the shrink fit changes, and therefore the holding force with which the body 16 of the casing 15 holds the stator 50 changes. Therefore, in the determining step, the quality of the fixation of the stator 50 to the body 16 is determined based on the estimated thickness of the insulating layer 56a. In this way, with this manufacturing method, the quality of the fixation of the stator 50 to the body 16 can be determined without disassembling the assembly 70.

[0010] A second aspect of the present disclosure is the first aspect, wherein the insulating layer (56a) is made of a resin.

[0011] In the second embodiment, the insulating layer (56a) is made of resin.

[0012] A third aspect of the present disclosure is the first or second aspect, wherein the electrical property measured in the measuring step is impedance.

[0013] In a third embodiment, in the measuring step, the impedance between the coil (57) and the body (16) in the assembly (70) is measured as the electrical characteristic.

[0014] A fourth aspect of the present disclosure is the third aspect, wherein in the determination step, the capacitance of a capacitor (84) formed by the core (51) and the body (16) is estimated based on the electrical characteristics of the assembly (70) measured in the measurement step, and the thickness of the insulating layer (56a) in the assembly (70) is estimated based on the estimated capacitance of the capacitor (84).

[0015] In the determination step of the fourth aspect, the capacitance of a capacitor 84 formed by the core 51 and the body 16 is estimated based on the impedance of the assembly 70 measured in the measurement step. In the assembly 70, an insulating layer 56a is sandwiched between the core 51 and the body 16. Therefore, the capacitance of the capacitor 84 formed by the core 51 and the body 16 varies depending on the thickness of the insulating layer 56a. Therefore, in the determination step, the thickness of the insulating layer 56a in the assembly 70 is estimated based on the estimated capacitance of the capacitor 84.

[0016] A fifth aspect of the present disclosure is any one of the first to fourth aspects, and includes an attachment step of attaching the compression mechanism (30), the rotor (45) of the electric motor (40), and end plate members (17, 18) that close the ends of the body (16) to the assembly (70) determined in the determination step to be in a good state of fixation of the stator (50) to the body (16).

[0017] In the fifth aspect, the fixing step, the measuring step, and the determining step are performed before the attaching step. Therefore, in the measuring step, the electrical characteristics between the coil (57) and the body (16) are measured for the assembly (70) to which the compression mechanism (30), the rotor (45), and the end plate members (17, 18) are not attached. Therefore, in the measuring step, the electrical characteristics between the coil (57) and the body (16) can be measured in a state where factors affecting the electrical characteristics between the coil (57) and the body (16) are minimal. As a result, the error in the estimated thickness of the insulating layer (56a) in the assembly (70) is reduced, and the accuracy of determining whether the stator (50) is properly fixed to the body (16) is improved.

[0018] A sixth aspect of the present disclosure is a compressor including a casing (15) having a cylindrical metal body (16), a compression mechanism (30) housed in the casing (15), and an electric motor (40) housed in the casing (15) and driving the compression mechanism (30), wherein a stator (50) of the electric motor (40) has a core (51), a coil (57), and an insulating layer (56a) covering an outer surface of the core (51), and the compressor is manufactured by the manufacturing method of any one of the first to fifth aspects.

[0019] In a fifth aspect, a compressor (10) in which a compression mechanism (30) and an electric motor (40) are housed in a casing (15) is manufactured by the manufacturing method of any one of the first to fourth aspects. [Brief explanation of the drawings]

[0020] [Figure 1] FIG. 1 is a vertical cross-sectional view of a compressor manufactured by a manufacturing method according to an embodiment. [Figure 2] FIG. 2 is a cross-sectional view of the compressor taken along line II-II in FIG. [Figure 3] FIG. 3 is a schematic vertical cross-sectional view showing the configuration of an assembly formed in the manufacturing process of the compressor. [Figure 4] FIG. 4 is a cross-sectional view of the assembly taken along line IV-IV in FIG. [Figure 5] FIG. 5 is a diagram showing a schematic diagram of the connection state between the assembly and the impedance measuring instrument. [Figure 6] FIG. 6 is a flow chart showing the operation of the determination device in the determination step. [Figure 7] FIG. 7 shows an equivalent circuit of the electric circuit formed in the assembly and a mathematical formula that represents the impedance of this equivalent circuit. [Figure 8] FIG. 8 is a schematic longitudinal cross-sectional view of the test assembly corresponding to FIG. [Figure 9] FIG. 9 shows an equivalent circuit of the electrical circuit formed in the test assembly and a mathematical formula that represents the impedance of this equivalent circuit. [Figure 10]FIG. 10 is a graph showing the relationship between the impedance of the electrical circuit formed in the test assembly and the frequency of the AC current. DETAILED DESCRIPTION OF THE INVENTION

[0021] The present embodiment is a method for manufacturing a compressor (10).

[0022] -Compressor- The compressor (10) manufactured by the manufacturing method of this embodiment will be described. The compressor (10) manufactured by this manufacturing method is a hermetic compressor in which a compression mechanism (30) and an electric motor (40) are housed in a single casing (15).

[0023] As shown in Fig. 1, the compressor (10) is a scroll compressor. Note that the type of compressor (10) shown here is merely an example. The compressor (10) manufactured by the manufacturing method of this embodiment is not limited to a scroll compressor, and may be, for example, a rolling piston type or a swing piston type rotary compressor.

[0024] The compressor (10) includes a casing (15), a compression mechanism (30), an electric motor (40), a lower bearing (60), and a drive shaft (65). In the internal space of the casing (15), the compression mechanism (30) is provided above the electric motor (40), and the lower bearing (60) is provided below the electric motor (40). The drive shaft (65) is attached to the rotor (45) of the electric motor (40) and drives the compression mechanism (30).

[0025] <Casing> As shown in Fig. 1, the casing (15) is a cylindrical member with both ends closed, and is disposed with its central axis extending substantially vertically.

[0026] The casing 15 includes a body 16, an upper end plate 17, and a lower end plate 18. The body 16, upper end plate 17, and lower end plate 18 are all made of metal such as steel. The body 16 is a cylindrical member. The upper end plate 17 and the lower end plate 18 are end plate members that close the ends of the body 16 and are formed in a bowl shape. The upper end plate 17 is provided to cover the upper end of the body 16. The lower end plate 18 is provided to cover the lower end of the body 16. The upper end plate 17 and the lower end plate 18 are each joined to the body 16 by welding.

[0027] An intake pipe 21 and a discharge pipe 22 are attached to the casing 15. The intake pipe 21 passes through the upper end plate 17 and connects to the compression mechanism 30. The discharge pipe 22 passes through the body 16 and opens into the space between the compression mechanism 30 and the electric motor 40 within the casing 15.

[0028] A power supply terminal 25 and a terminal cover 26 are attached to the body 16 of the casing 15. The power supply terminal 25 is provided so as to pass through the body 16. The power supply terminal 25 is electrically connected to a coil 57 of the stator 50, which will be described later. The terminal cover 26 is fixed to the outer surface of the body 16 and covers the power supply terminal 25.

[0029] <Compression mechanism> As shown in FIG. 1, the compression mechanism (30) is a scroll-type fluid machine.

[0030] The compression mechanism (30) includes a fixed scroll (31), an orbiting scroll (32), and a housing (33). The housing (33) is disposed across the upper portion of the body (16). The housing (33) is fixed to the body (16) by spot welding. A main bearing (34) is formed in the housing (33). The main bearing (34) is a plain bearing that supports the drive shaft (65). The fixed scroll (31) is disposed on top of the housing (33). The fixed scroll (31) is fixed to the housing (33) by bolts. The orbiting scroll (32) is disposed between the housing (33) and the fixed scroll (31). The orbiting scroll (32) is driven by the drive shaft (65).

[0031] The fixed scroll (31) and the orbiting scroll (32) each have a spiral wall-shaped wrap. In the compression mechanism (30), the wraps of the fixed scroll (31) and the orbiting scroll (32) mesh with each other to form a compression chamber (35).

[0032] <Electric motor> 1 and 2, the electric motor (40) includes a stator (50) and a rotor (45). The stator (50) is fixed to the body (16) of the casing (15). The rotor (45) is disposed inside the stator (50).

[0033] The stator (50) includes a core (51), a coil (57), and a resin member (56). The core (51) is made of a large number of laminated electromagnetic steel plates. The core (51) includes a back yoke (52) and a plurality of (six in this embodiment) teeth (53). The back yoke (52) is formed in a generally cylindrical shape. Each tooth (53) protrudes radially inward from the inner circumferential surface of the back yoke (52). The coil (57) is made of copper wire wound around each tooth (53).

[0034] A plurality of (six in this embodiment) core cuts 54 are formed on the outer peripheral surface of the back yoke 52. The core cuts 54 are grooves extending in the axial direction of the core 51. The core cuts 54 are formed from one end to the other end of the core 51.

[0035] In the back yoke (52), the portions between adjacent core cuts (54) form protrusions (55). Six protrusions (55) are formed in the core (51) of this embodiment. The protrusions (55) are portions that protrude relatively outward in the radial direction of the back yoke (52). Like the core cuts (54), the protrusions (55) are formed from one end to the other end of the core (51). The protruding end surfaces (55a) of the protrusions (55) are part of the outer surface of the core (51) and face the inner surface of the body (16) of the casing (15).

[0036] The resin member (56) is a plate-like member formed in a groove shape. The core (51) is provided with the same number of resin members (56) as the number of protrusions (55). One resin member (56) is provided for each protrusion (55). Each resin member (56) covers its corresponding protrusion (55). The resin member (56) is provided from one end to the other end of the core (51). The resin member (56) covers the entire end faces (55a) of the protrusions (55). The portion of the resin member (56) that covers the end faces (55a) of the protrusions (55) constitutes a resin insulating layer (56a). The insulating layer (56a) provides electrical insulation between the core (51) of the stator (50) and the body (16) of the casing (15).

[0037] The resin member 56 is made of a thermoplastic resin. Examples of resins that can be used to make the resin member 56 include PPS (polyphenylene sulfide), LCP (liquid crystal polymer), PBT (polybutylene terephthalate), polyimide, PBI (polybenzimidazole), PEEK (polyether ether ketone), PSF (polysulfone), and PPO (polyphenylene oxide). The resin member 56 may also be made of a composite material in which glass fiber is mixed into one of these thermoplastic resins. Note that the materials for the resin member 56 shown here are merely examples.

[0038] The rotor (45) is cylindrical. A plurality of slots (46) (four in this embodiment) are formed in the rotor (45). A permanent magnet is embedded in each slot (46). A drive shaft (65) is inserted through the rotor (45).

[0039] <Lower bearing> The lower bearing 60 includes a main body 61 and multiple (e.g., three) leg portions 62. The main body 61 is generally cylindrical and serves as a sliding bearing supporting the drive shaft 65. The leg portions 62 protrude radially outward from the main body 61. Each leg portion 62 is joined to the trunk 16 of the casing 15 by spot welding.

[0040] <Drive shaft> The drive shaft (65) is provided along the axial direction (vertical direction) of the casing (15). An upper end of the drive shaft (65) forms an eccentric portion (66) that is connected to the orbiting scroll (32). The drive shaft (65) is rotatably supported by the main bearing (34) of the housing (33) and the body portion (61) of the lower bearing (60).

[0041] -Compressor operation- The operation of the compressor (10) will now be described.

[0042] When power is supplied to the coil (57) of the electric motor (40) through the power supply terminal (25), the rotor (45) of the electric motor (40) rotates, and the orbiting scroll (32) is driven by the drive shaft (65). When the orbiting scroll (32) is driven, low-pressure refrigerant is drawn into the compression chamber (35) through the suction pipe (21) and compressed. The refrigerant compressed in the compression chamber (35) is discharged from the compression mechanism (30) into the internal space of the casing (15) and flows out of the casing (15) through the discharge pipe (22).

[0043] -Compressor manufacturing method- The following describes a method for manufacturing the compressor 10. This manufacturing method includes a fixing step, a measuring step, a determining step, and an attaching step.

[0044] <Fixed process> The fixing process is a process of combining the body 16 of the casing 15 with the stator 50 of the electric motor 40 to form an assembly 70. In the fixing process, the stator 50 is fixed to the body 16 by shrink fitting.

[0045] At room temperature, the inner diameter of the single body 16 is slightly smaller than the outer diameter of the stator 50. The body 16 is heated, for example, to 250°C or higher. The inner diameter of the heated body 16 is slightly larger than the outer diameter of the stator 50. The stator 50 is inserted into the heated body 16, which has reached a high temperature. The body 16 is then cooled. As the temperature of the body 16 decreases and the inner diameter of the body 16 shrinks, the inner surface of the body 16 comes into close contact with the stator 50. As a result, the stator 50 is fixed to the body 16.

[0046] As shown in FIGS. 3 and 4 , the assembly 70 is formed by fixing the stator 50 to the body 16. In the assembly 70, the stator 50 is disposed near the center of the body 16 in the axial direction (vertical direction). As described above, the protruding portions 55 of the core 51 constituting the stator 50 have their end faces 55 a covered with an insulating layer 56 a made of a resin member 56. Therefore, in the assembly 70, the insulating layer 56 a is sandwiched between the end faces 55 a of the protruding portions 55 of the core 51 and the inner surface of the body 16. In the assembly 70, the coil 57 of the stator 50 is electrically connected to the power supply terminal 25 via the power supply wire 27.

[0047] <Measurement process> The measurement step is a step of measuring the electrical characteristics of the assembly 70 formed in the fixing step. The electrical characteristic of the assembly 70 measured in the measurement step is impedance. The measurement step is performed after the temperature of the body 16 of the assembly 70 formed in the fixing step has returned to approximately room temperature.

[0048] As shown in Fig. 5, in the measurement step, an impedance meter 75 is electrically connected to the assembly 70. An LCR meter may be used as the impedance meter 75. The impedance meter 75 is electrically connected to the coil 57 of the stator 50 via the power supply terminal 25 and the power supply line 27. The impedance meter 75 is also electrically connected to the body 16 that constitutes the assembly 70.

[0049] The impedance meter 75 measures the impedance between the coil 57 of the assembly 70 and the body 16. The impedance meter 75 measures the impedance at a predetermined reference frequency. The reference frequency is, for example, 10 kHz to 600 kHz. The impedance meter 75 transmits the measured impedance value to a determination device 76.

[0050] <Judgment process> The determination step is a step of estimating the thickness of the insulating layer 56 a in the assembly 70 based on the impedance of the assembly 70 measured by the impedance measuring instrument 75, and determining whether the stator 50 is properly fixed to the body 16 based on the estimated thickness of the insulating layer 56 a.

[0051] The determination step is performed by a determination device 76. The determination device 76 is configured by a computer. This computer functions as the determination device 76 by executing a predetermined program.

[0052] The process performed by the determination device (76) in the determination step will be described with reference to the flowchart of FIG.

[0053] (Step ST1) In the process of step ST1, the determination device 76 acquires the impedance of the assembly 70 measured by the impedance measuring device 75 in the measurement step.

[0054] (Step ST2) In the next step ST2, the determination device 76 compares the impedance measurement value Z acquired in step ST1 with a predetermined reference impedance Z c Compare with.

[0055] The measured impedance value Z is the reference impedance Z c is greater than or equal to (Z≧Z c If the above condition is met, the decision device (76) performs the process of step ST3.

[0056] On the other hand, if this condition is not met, the measured impedance value Z will be less than the reference impedance Z c If the difference is smaller than 1 / 2, it can be determined that the insulation between the core 51 and the body 16 in the assembly 70 is insufficient. If this condition is not met, the determination device 76 determines that the assembly 70 being determined is defective, and performs the process of step ST7.

[0057] (Step ST3) In the process of step ST3, the determination device 76 calculates the capacitance C2. The capacitance C2 is the capacitance of a pseudo-capacitor formed by the core 51 and the body 16 of the assembly 70. The process by which the determination device 76 calculates the capacitance C2 will be described later.

[0058] (Step ST4) In the process of step ST4, the determination device 76 calculates the thickness t of the insulating layer 56a in the assembly 70 based on the capacitance C2 calculated in the process of step ST3. The process of the determination device 76 calculating the thickness t of the insulating layer 56a will be described later.

[0059] (Step ST5) In the process of step ST5, the determination device 76 calculates the thickness t of the insulating layer 56a calculated in the process of step ST4 by comparing it with a predetermined reference thickness t c Compare with.

[0060] As described above, in the fixing process, the stator 50 is fixed to the body 16 by shrink fitting. During this process, if the resin member 56 of the stator 50 comes into contact with the high-temperature body 16, the resin member 56 may melt. If the body 16 contracts while the resin member 56 is molten, part of the molten resin member 56 will be extruded from between the protruding portion 55 of the stator 50 and the body 16.

[0061] When a portion of the molten resin member 56 is extruded from between the protruding portion 55 of the stator 50 and the body 16, the interference caused by the shrink fit is smaller than when the resin member 56 does not melt, and the holding force with which the body 16 holds the stator 50 is reduced. Also, in this case, the thickness of the insulating layer 56a when the temperature of the body 16 returns to approximately room temperature is thinner than when the resin member 56 does not melt during the shrink fit process. Therefore, the degree of holding force with which the body 16 holds the stator 50 can be estimated based on the thickness of the insulating layer 56a when the temperature of the body 16 returns to approximately room temperature.

[0062] Therefore, the thickness t of the insulating layer (56a) calculated in the process of step ST4 is set to the reference thickness t c The condition is that t≧t c ) is satisfied, the determination device 76 determines that the body 16 has a sufficient holding force to hold the stator 50, and performs the process of step ST6. On the other hand, if this condition is not satisfied, the determination device 76 determines that the body 16 does not have enough holding force to hold the stator 50, and performs the process of step ST7.

[0063] (Step ST6) In the process of step ST6, the determination device 76 displays a message that the assembly 70 being determined is a pass product. Examples of the display that the assembly 70 is a pass product include displaying a message on a display screen and turning on a blue lamp.

[0064] (Step ST7) In the process of step ST7, the determination device 76 displays a message that the assembly 70 being determined is defective. Examples of the display that the assembly 70 is defective include displaying a message on a display screen and turning on a red lamp.

[0065] <Installation process> The attachment step is a step of attaching components of the compressor (10) to the assembly (70) that has been determined to be a non-defective product in the determination step.

[0066] In the installation process, the compression mechanism 30 and the rotor 45 combined with the drive shaft 65 are installed to the assembly 70. Also, in the installation process, the upper end plate 17 and the lower end plate 18 are installed to the body 16 of the assembly 70.

[0067] -Capacitance C2- The process of calculating the capacitance C2 by the determination device (76) will be described.

[0068] <Equivalent circuit of assembly> As shown in Figure 7, the equivalent circuit, which is a simplified representation of the electrical circuit formed between the coil 57 of the assembly 70 and the body 16, is a circuit in which a composite resistor 81, a composite inductor 82, a first capacitor 83, and a second capacitor 84 are connected in series. The first capacitor 83 is a pseudo-capacitor formed by the coil 57 and the core 51 of the stator 50. The second capacitor 84 is a pseudo-capacitor formed by the core 51 of the assembly 70 and the body 16.

[0069] The impedance Z of this equivalent circuit is calculated using Equation 1 and Equation 2 shown in FIG. 7. R is the resistance value of the combined resistor (81). L is the inductance of the combined inductor (82). C1 is the capacitance of the first capacitor (83). C2 is the capacitance of the second capacitor (84). ω is the angular frequency expressed as ω = 2πf. f is the frequency of the AC current flowing through the equivalent circuit.

[0070] <Calculation of R, L, and C1> The resistance value R of the combined resistor (81), the inductance L of the combined inductor (82), and the capacitance C1 of the first capacitor (83) are constant regardless of the thickness t of the insulating layer (56a). The resistance value R, the inductance L, and the capacitance C1 are substantially the same for each assembly (70) constituting the same model of compressor (10). Therefore, the determining device (76) stores the "resistance value R, inductance L, and capacitance C1" for each model of compressor (10) manufactured in association with the model of the compressor (10).

[0071] The resistance value R of the combined resistor (81), the inductance L of the combined inductor (82), and the capacitance C1 of the first capacitor (83) are calculated in advance before production of the compressor (10) is started, and are recorded in the determination device (76). The process of calculating the resistance value R, the inductance L, and the capacitance C1 will be described.

[0072] First, a test assembly (90) is prepared as shown in Fig. 8. The test assembly (90) is the assembly (70) shown in Fig. 3 from which the resin member (56) of the stator (50) is omitted.

[0073] The structure of the stator 50 constituting the test assembly 90 is the same as the structure of the stator 50 constituting the assembly 70, except that the resin member 56 is omitted. The inner diameter of the body 16 constituting the test assembly 90 is slightly smaller than the inner diameter of the body 16 constituting the assembly 70. Therefore, in the test assembly 90, when the stator 50 is fixed to the body 16 by shrink fitting, the protruding end surface 55a of the protruding portion 55 of the core 51 is in close contact with the inner surface of the body 16, and the core 51 of the stator 50 and the body 16 are electrically connected.

[0074] As shown in FIG. 9, the equivalent circuit, which is a simplified representation of the electrical circuit formed between the coil (57) and the body (16) of the test assembly (90), is a circuit in which a combined resistor (81), a combined inductor (82), and a first capacitor (83) are connected in series.

[0075] The impedance Z of this equivalent circuit is calculated using Equation 3 shown in FIG. 9. R is the resistance value of the combined resistor (81). L is the inductance of the combined inductor (82). C1 is the capacitance of the first capacitor (83). ω is the angular frequency expressed as ω=2πf. f is the frequency of the AC current flowing through the equivalent circuit.

[0076] As described above, the only substantial difference between the test assembly 90 and the assembly 70 is the omission of the resin member 56. Therefore, the resistance value R of the combined resistor 81, the inductance L of the combined inductor 82, and the capacitance C1 of the first capacitor 83 in the test assembly 90 are substantially equal to the resistance value R of the combined resistor 81, the inductance L of the combined inductor 82, and the capacitance C1 of the first capacitor 83 in the assembly 70, respectively. Therefore, the process of calculating the resistance value R, inductance L, and capacitance C1 in the test assembly 90 is now described.

[0077] First, the impedance between the coil 57 and the body 16 in the test assembly 90 is measured. The impedance is measured at multiple frequencies. The measured impedance for the test assembly 90 is shown by the solid line in the graph of FIG. 10. In the graph of FIG. 10, the relationship between frequency and impedance shown by the solid line is roughly linear in the frequency range of 10 kHz to 600 kHz. Therefore, the resistance R, inductance L, and capacitance C1 of the test assembly 90 are calculated using the least squares method based on the data in the frequency range of 10 kHz to 600 kHz and Equation 3.

[0078] 10, the relationship between frequency and impedance for the assembly 70 having the resin member 56 is shown by a dashed line. Because the equivalent circuit of the assembly 70 includes the second capacitor 84, the impedance of the assembly 70 is higher than the impedance of the test assembly 90 at all frequencies.

[0079] <Calculation of C2> The capacitance C2 of the second capacitor (84) varies depending on the thickness t of the insulating layer (56a). Therefore, the capacitance C2 of each of the assemblies (70) constituting the same model of compressor (10) is not necessarily the same.

[0080] Therefore, the determination device (76) calculates the capacitance C2 of the assembly (70) to be determined in the process shown in step ST3 of Fig. 6. Specifically, the determination device (76) reads out the resistance R, inductance L, and capacitance C1 corresponding to the model of the compressor (10) included in the assembly (70) to be determined from a storage device such as a memory device. Then, the determination device (76) calculates the capacitance C2 of the assembly (70) to be determined by substituting the "impedance Z of the assembly (70) to be determined" obtained in the process of step ST1 of Fig. 6 and the resistance R, inductance L, and capacitance C1 read out from the storage device into Equation 1 and Equation 2 shown in Fig. 7.

[0081] -thickness of insulating layer t- 6, the determination device 76 calculates the thickness t of the insulating layer 56a in the assembly 70 based on the capacitance C2 of the second capacitor 84 calculated in step ST3. The process of calculating the thickness t of the insulating layer 56a by the determination device 76 will be described.

[0082] As described above, the second capacitor 84 is a pseudo-capacitor formed by the core 51 and the body 16 of the assembly 70. The second capacitor 84 can be approximated as a parallel plate capacitor, with the core 51 as one electrode, the body 16 as the other electrode, and the insulating layer 56a as the dielectric. The capacitance C2 of the second capacitor 84 when approximated as a parallel plate capacitor is expressed by the following equation 4: C2=εS / d (Equation 4)

[0083] ε is the dielectric constant of the insulating layer (56a), which is a dielectric. S is the area of ​​the electrode. The area S of the electrode of the second capacitor (84) is the sum of the areas of the tip faces (55a) of all the protrusions (55) formed on the core (51). d is the distance between the electrodes. The distance between the electrodes of the second capacitor (84) is equal to the thickness t of the insulating layer (56a). The determination device (76) stores the "dielectric constant ε and electrode area S of the second capacitor (84)" for each model of the compressor (10) to be manufactured, in association with the model of the compressor (10).

[0084] In the process of calculating the thickness t of the insulating layer (56a) in the assembly (70), the determination device (76) reads out from a storage device such as a memory device the "dielectric constant ε and electrode area S of the second capacitor (84)" corresponding to the model of the compressor (10) included in the assembly (70) to be determined. The determination device (76) then calculates the inter-electrode distance d by substituting the read-out dielectric constant ε and electrode area S and the capacitance C2 of the second capacitor (84) calculated in the process of step ST3 in FIG. 6 into Equation 4. The determination device (76) stores the calculated inter-electrode distance d in the storage device as the thickness t of the insulating layer (56a) in the assembly (70) to be determined.

[0085] <Accuracy of estimated thickness t> In the assembly 70, a capacitor is formed not only between the protrusion 55 of the core 51 and the body 16, but also between the portion of the core 51 corresponding to the core cut 54 and the body 16. However, in the determination step of this embodiment, the capacitance of the capacitor formed by the portion of the core 51 corresponding to the core cut 54 and the body 16 is ignored, and the thickness t of the insulating layer 56a in the assembly 70 is calculated using the above equation 4. The reason for this will be explained.

[0086] As shown in Figure 4, the inter-electrode distance of the capacitor formed by the protrusion (55) of the core (51) and the body (16) is the thickness t of the insulating layer (56a). The thickness t of the insulating layer (56a) is, for example, about 1 mm. The inter-electrode distance of the capacitor formed by the part of the core (51) corresponding to the core cut (54) and the body (16) is the depth D of the core cut (54). The depth D of the core cut (54) is, for example, about 5 mm.

[0087] The depth D of the core cut (54) can be considered to be sufficiently larger than the thickness t of the insulating layer (56a). Therefore, the capacitance of the capacitor formed by the portion of the core (51) corresponding to the core cut (54) and the body (16) can be considered to be sufficiently smaller than the capacitance of the capacitor formed by the protrusion (55) of the core (51) and the body (16). This is the first reason.

[0088] In the determination step of this embodiment, the thickness t of the insulating layer 56a is calculated to determine whether the body 16 has sufficient holding power to hold the stator 50. To accurately determine whether the body 16 has sufficient holding power to hold the stator 50, it is sufficient to estimate with relatively high accuracy the relative difference in the thickness t of the insulating layer 56a for each of the assemblies 70 to be determined. Therefore, even if the calculated value of the thickness t of the insulating layer 56a for each assembly 70 contains some error, it is still possible to accurately determine whether the body 16 has sufficient holding power to hold the stator 50. This is the second reason.

[0089] In the determination process of this embodiment, for the first and second reasons described above, the capacitance C2 of the pseudo-capacitor (condenser) formed by the core (51) and the body (16) of the assembly (70) is considered to be substantially equal to the capacitance of the capacitor formed by the protrusion (55) of the core (51) and the body (16), and the thickness t of the insulating layer (56a) in the assembly (70) is calculated using the above-mentioned equation 4.

[0090] -Features of the embodiment (1)- The manufacturing method of this embodiment includes a fixing step, a measuring step, and a determining step. In the assembly 70 formed in the fixing step, an insulating layer 56a is sandwiched between the inner surface of the body 16 of the casing 15 and the outer surface of the core 51 of the stator 50. In the measuring step, the impedance between the coil 57 and the body 16 in the assembly 70 is measured.

[0091] The impedance between the coil 57 and the body 16 in the assembly 70 varies depending on the thickness t of the insulating layer 56a. Therefore, in the determination step, the thickness t of the insulating layer 56a in the assembly 70 is estimated based on the impedance measured in the measurement step. Furthermore, if the thickness t of the insulating layer 56a in the assembly 70 changes, the interference in the shrink fit changes, and therefore the holding force with which the body 16 of the casing 15 holds the stator 50 changes. Therefore, in the determination step, the quality of the fixation of the stator 50 to the body 16 is determined based on the estimated thickness t of the insulating layer 56a. In this way, the manufacturing method of this embodiment allows the quality of the fixation of the stator 50 to the body 16 to be determined without disassembling the assembly 70.

[0092] -Features of the embodiment (2)- In the manufacturing method of this embodiment, the fixing step, the measuring step, and the determining step are performed before the mounting step. Therefore, in the measuring step, the impedance between the coil 57 and the body 16 is measured for the assembly 70 to which the compression mechanism 30, the rotor 45, and the end plate members 17, 18 are not attached. Therefore, in the measuring step, the impedance between the coil 57 and the body 16 can be measured in a state where factors affecting the impedance between the coil 57 and the body 16 are minimal. As a result, the error in the estimated value of the thickness t of the insulating layer 56a in the assembly 70 can be reduced, thereby improving the accuracy of determining whether the stator 50 is properly fixed to the body 16.

[0093] -Modification 1 of the embodiment- The determination device (76) used in the manufacturing method of this embodiment calculates the capacitance C2 of the assembly (70) to be determined using Equations 1 and 2 shown in FIG. 7 in the process shown in step ST3 of FIG. 6.

[0094] However, the formulas used by the determination device 76 to calculate the capacitance C2 are not limited to Formula 1 and Formula 2 shown in Fig. 7. For example, the determination device 76 may be configured to calculate the capacitance C2 of the assembly 70 using one or both of Formulas 1 and 2 shown in Fig. 7 with a correction coefficient or correction term introduced therein.

[0095] -Modification 2 of the embodiment- In the process shown in step ST3 of FIG. 6, the determination device (76) used in the manufacturing method of this embodiment performs a calculation process in which the resistance value R, inductance L, and capacitance C1 read from the storage device and the impedance of the assembly (70) acquired in the process of step ST1 are substituted into Formula 1 and Formula 2 shown in FIG. 7, and the calculation process calculates the capacitance C2 of the assembly (70) to be determined.

[0096] However, the process for calculating the capacitance C2 of the assembly 70 in the manufacturing method of this embodiment is not limited to this calculation process. In the manufacturing method of this embodiment, the capacitance C2 of the assembly 70 to be determined may be calculated by, for example, performing the following process.

[0097] In the measurement step of the manufacturing method of this modified example, the impedance between the coil 57 and the body 16 of the assembly 70 is measured at multiple frequencies. The impedance of the assembly 70 measured in the measurement step is recorded in a storage device such as a memory device in association with the frequency at which the impedance was measured. In this way, the measurement step obtains multiple data sets, each consisting of the "impedance of the assembly 70" and the "frequency at which the impedance was measured."

[0098] In the determination step of the manufacturing method of this modified example, the determination device (76) reads from the storage device the plurality of data sets obtained in the measurement step, and also reads from the storage device the resistance R, the inductance L, and the capacitance C1 corresponding to the model of the compressor (10) included in the assembly (70) to be determined.

[0099] The determination device 76 calculates the impedance of the assembly 70 using the resistance value R, inductance L, and capacitance C1 read from the storage device and Equation 1 and Equation 2 shown in Fig. 7. The determination device 76 then calculates, using, for example, the least squares method, the value of capacitance C2 that minimizes the error between the "calculated impedance (calculated value)" and the "impedance (actual measured value) constituting each data set obtained in the measurement process."

[0100] Although the embodiments and modifications have been described above, it will be understood that various modifications in form and detail are possible without departing from the spirit and scope of the claims. Furthermore, elements of the above embodiments, modifications, and other embodiments may be combined or substituted as appropriate. Furthermore, the terms "first," "second," "third," etc. in the specification and claims are used to distinguish the terms to which these terms are attached, and do not limit the number or order of the terms. [Industrial Applicability]

[0101] As described above, the present disclosure is useful for a compressor manufacturing method and a compressor. [Explanation of symbols]

[0102] 10 Compressor 15 Casing 16 Torso 17 Upper end plate (end plate member) 18 Lower end plate (end plate member) 30 Compression mechanism 40 Electric motor 50 stator 51 cores 56a Insulating layer 57 Coil 70 Assembly

Claims

1. A method for manufacturing a compressor (10) in which a compression mechanism (30) and an electric motor (40) for driving the compression mechanism (30) are housed inside a casing (15) having a cylindrical metal body (16), and the stator (50) of the electric motor (40) has a core (51), a coil (57), and an insulating layer (56a) covering an outer surface of the core (51), a fixing step of fixing the stator (50) to the body (16) by shrink fitting, thereby forming an assembly (70) in which the body (16) and the stator (50) are combined with each other in a state in which the insulating layer (56a) is sandwiched between the inner surface of the body (16) and the outer surface of the core (51); a measuring step of measuring an electrical characteristic between the coil (57) and the body (16) in the assembly (70); and a determining step of estimating a thickness of the insulating layer (56a) in the assembly (70) based on the electrical characteristics of the assembly (70) measured in the measuring step, and determining whether or not the state of fixation of the stator (50) to the body (16) is good based on the estimated thickness of the insulating layer (56a). A method for manufacturing a compressor.

2. The insulating layer (56a) is made of resin. A method for manufacturing the compressor according to claim 1.

3. The electrical characteristic measured in the measurement step is impedance. A method for manufacturing a compressor according to claim 1 or 2.

4. In the determination step, estimating the capacitance of a capacitor (84) formed by the core (51) and the body (16) based on the electrical characteristics of the assembly (70) measured in the measuring step; The thickness of the insulating layer (56a) in the assembly (70) is estimated based on the estimated capacitance of the capacitor (84). The method for manufacturing the compressor according to claim 3.

5. and an attachment step of attaching the compression mechanism (30), the rotor (45) of the electric motor (40), and end plate members (17, 18) for closing the ends of the body (16) to the assembly (70) determined in the determination step to be in a good state of fixation of the stator (50) to the body (16). A method for manufacturing a compressor according to claim 1 or 2.

6. a casing (15) having a cylindrical metal body (16); a compression mechanism (30) housed in the casing (15); an electric motor (40) accommodated in the casing (15) and driving the compression mechanism (30); The stator (50) of the electric motor (40) includes a core (51), a coil (57), and an insulating layer (56a) covering the outer surface of the core (51), A compressor manufactured by the manufacturing method according to claim 1 or 2.

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