Electric motor assembling method

Abstract

Provided is a scroll compressor assembling method comprising: a fixing step (S101), in which a stator has a plurality of excitation magnetic poles, and a rotor has a plurality of first magnetization portions magnetized to a N-pole and a plurality of second magnetization portions magnetized to a S-pole, the first magnetization portions and the second magnetization portions being alternately disposed along a circumferential direction around an axis line, a rotation position of the rotor being fixed so that the rotor does not rotate around the axis line; a current supply step of supplying a magnetization current to an excitation magnetic pole of a predetermined phase included in a plurality of excitation magnetic poles; and an insertion step (S103) in which, in a state in which a position of either a first magnetization portion or a second magnetization portion in a circumferential position having the same polarity as the excitation magnetic pole of the predetermined phase magnetized by the current supply step coincides with the position of the excitation magnetic pole of the predetermined phase in the circumferential direction, the rotor, of which the rotation position is fixed in the fixing step, is inserted into the stator along the axis line, and a tip portion of the rotor is brought into the state of being supported by a bearing portion.

Description

How to assemble an electric motor

[0001] The present disclosure relates to a method for assembling an electric motor.

[0002] Conventionally, an electric supercharging compressor including a motor that drives the compressor has been known (see, for example, Patent Document 1). Patent Document 1 discloses that when a stator is inserted into a rotor including a powerful permanent magnet and assembled, a protective sleeve made of a nonmagnetic material such as nylon is attached to the rotor to prevent the stator and other metal components from coming into contact with the rotor due to magnetic force and becoming stuck or being damaged. Patent Document 1 also discloses that after the stator is inserted into the rotor and assembled, the protective sleeve is pulled out and removed from the rotor.

[0003] JP 2015-169073 A

[0004] However, for example, when inserting and assembling a rotor into a fixed stator, if the structure does not allow the protective tube to be removed from the rotor after the rotor is inserted, the rotor and stator cannot be protected by components such as the protective tube disclosed in Patent Document 1.

[0005] The present disclosure has been made in consideration of the above circumstances, and aims to provide a method for assembling an electric motor that can prevent the rotor from coming into contact with the stator when inserting the rotor into the stator.

[0006] In a method for assembling an electric motor according to one aspect of the present disclosure, the electric motor comprises: a housing formed in a cylindrical shape extending along an axis; a motor having a stator arranged inside the housing so as to extend along the axis; and a rotor arranged on the inner periphery of the stator; a drive unit that is rotationally driven by the motor; and a bearing unit that is fixed to a bottom part of the housing and supports a tip end of the rotor, wherein the stator has a plurality of excitation poles corresponding to a plurality of phases of excitation current, and the rotor has a plurality of first magnetized portions magnetized to N poles and a plurality of second magnetized portions magnetized to S poles, and the first magnetized portions and the second magnetized portions are arranged to rotate around the axis. the rotors are arranged alternately along the circumferential direction, and the method comprises: a fixing step of fixing a rotational position of the rotor so that the rotor does not rotate around the axis; a current supply step of supplying a magnetizing current to the exciting magnetic poles of a predetermined phase included in the plurality of exciting magnetic poles; and an insertion step of inserting the rotor, whose rotational position has been fixed by the fixing step, into the stator along the axis in a state in which the circumferential position of either the first magnetized portion or the second magnetized portion, which has the same polarity as the exciting magnetic pole of the predetermined phase magnetized by the current supply step, coincides with the circumferential position of the exciting magnetic pole of the predetermined phase, so that the tip end of the rotor is supported by the bearing portion.

[0007] According to the present disclosure, it is possible to provide a method for assembling an electric motor that can prevent the rotor from coming into contact with the stator when inserting the rotor into the stator.

[0008] 1 is a longitudinal cross-sectional view showing a schematic configuration of a scroll compressor according to an embodiment of the present disclosure, illustrating an assembled state of the scroll compressor; FIG. 2 is a cross-sectional view taken along the arrows A-A of the scroll compressor shown in FIG. 1, with the front housing omitted; FIG. 3 is a longitudinal cross-sectional view showing a schematic configuration of a scroll compressor according to an embodiment of the present disclosure, illustrating a state before the scroll compressor is assembled; FIG. 4 is a cross-sectional view taken along the arrows B-B of the scroll compressor shown in FIG. 3, with the front housing omitted; and FIG. 5 is a flowchart showing an assembly method of a scroll compressor according to an embodiment of the present disclosure.

[0009] A method for assembling a scroll compressor (electric motor) 100 according to an embodiment of the present disclosure will be described with reference to the drawings. The scroll compressor 100 of this embodiment is used in, for example, a vehicle air conditioner.

[0010] Fig. 1 is a vertical cross-sectional view showing a schematic configuration of a scroll compressor 100 according to this embodiment, showing the assembled state of the scroll compressor 100. As shown in Fig. 1, the scroll compressor 100 includes a bearing housing (first housing) 10, a rear housing (second housing) 20, a front housing (third housing) 30, a scroll compression mechanism (drive unit; compression unit) 40, a motor 50, a first bearing unit 60, a second bearing unit 65, an inverter 70, and a gasket 80.

[0011] The bearing housing 10, the rear housing 20, and the front housing 30 form the outer shell of the scroll compressor 100 and are made of an aluminum alloy. The bearing housing 10 is formed in a cylindrical shape along an axis X1 that is the center of rotation of the orbiting scroll 42. The bearing housing 10 has an internal space that accommodates the first bearing portion 60 and the scroll compression mechanism 40.

[0012] The rear housing 20 seals one end of the bearing housing 10 along the axis X1, and is provided with a discharge port (not shown) for refrigerant gas compressed by the scroll compression mechanism 40. The front housing 30 seals the other end of the bearing housing 10 along the axis X1, and is provided with an internal space that houses the motor 50 and the inverter 70. The internal space of the front housing 30 that houses the motor 50 communicates with the internal space of the bearing housing 10 that houses the first bearing portion 60. The internal space that houses the motor 50 and the internal space that houses the inverter 70 are independent spaces that do not communicate with each other.

[0013] The front housing 30 is provided with a suction port 31 for drawing in a refrigerant. Refrigerant supplied from the outside is introduced into the internal space of the front housing 30 through the suction port 31. The refrigerant introduced into the front housing 30 passes through the motor 50 along the axis X1 and is guided toward the scroll compression mechanism 40. The refrigerant drawn through the suction port 31 is a mixed refrigerant (fluid) containing lubricating oil and refrigerant gas.

[0014] The bearing housing 10 and the rear housing 20 are formed with insertion holes into which fastening bolts 90 are inserted. The end of the front housing 30 on the bearing housing 10 side is formed with fastening holes (not shown) into which male threads formed at the tip of the fastening bolts 90 are fastened. By fastening the fastening bolts 90 into the fastening holes formed in the front housing 30, the bearing housing 10 is fixed in a state where it is sandwiched between the rear housing 20 and the front housing 30 along the axis X1.

[0015] The scroll compression mechanism 40 is a device that is disposed inside the bearing housing 10 and rotates about the axis X1 to compress the refrigerant gas. The scroll compression mechanism 40 is driven to rotate about the axis X1 by a motor 50. The scroll compression mechanism 40 has a fixed scroll 41 that is fixedly sandwiched between the bearing housing 10 and the rear housing 20, and an orbiting scroll 42 that meshes with the fixed scroll 41. The scroll compression mechanism 40 compresses the refrigerant gas by orbiting the orbiting scroll 42 relative to the fixed scroll 41 using the driving force of the motor 50.

[0016] The fixed scroll 41 has a spiral wrap (first wall) 41B that is a wall provided on one side of an end plate (first end plate) 41A. The end plate 41A has a discharge port 41C formed therein through which the refrigerant gas compressed by the fixed scroll 41 and the orbiting scroll 42 is discharged.

[0017] The orbiting scroll 42 has a spiral wrap (second wall) 42B, which is a wall provided on one side of an end plate (second end plate) 42A. The orbiting scroll 42 is connected to an eccentric shaft (not shown) connected to a motor 50, and is supported so as to be capable of orbital rotation via a rotation-preventing mechanism (not shown). The orbiting scroll 42 is meshed with the spiral wrap 41B of the fixed scroll 41, and is supported so as to be capable of orbital rotation while being prevented from rotating.

[0018] 1, the scroll compression mechanism 40 has a reed valve 43 attached to the fixed scroll 41 so as to close the discharge port 41C. The reed valve 43 opens when the pressure of the refrigerant gas in the compression chamber 40A reaches or exceeds a predetermined pressure, and guides the refrigerant gas discharged from the discharge port 41C to the discharge space 41D. The refrigerant gas guided to the discharge space 41D is then guided to the outside through a discharge port (not shown).

[0019] The motor 50 is a device that drives the orbiting scroll 42 of the scroll compression mechanism 40 to rotate about the axis X1 relative to the fixed scroll 41. The motor 50 is connected to the orbiting scroll 42 via an eccentric shaft (not shown). Here, details of the motor 50 will be described with reference to FIG. 2. FIG. 2 is a cross-sectional view of the scroll compressor 100 shown in FIG. 1 taken along the line A-A, with the front housing 30 omitted. As shown in FIGS. 1 and 2, the motor 50 has a stator 51 and a rotor 52 that is disposed on the inner circumferential side of the stator 51.

[0020] The stator 51 is formed by laminating a predetermined number of electromagnetic steel plates that have been punched into an annular shape. The stator 51 is disposed inside the bearing housing 10 so as to extend along the axis X1. As shown in FIG. 2 , a plurality of teeth 51 a are provided on the inner periphery of the stator 51. Coil windings 51 b are wound around each of the plurality of teeth 51 a via bobbins (not shown).

[0021] During normal operation of the motor 50, the stator 51 has a first excitation magnetic pole 51c1 corresponding to a U-phase excitation current, a second excitation magnetic pole 51c2 corresponding to a V-phase excitation current, and a third excitation magnetic pole 51c3 corresponding to a W-phase excitation current. As shown in Fig. 2, the first excitation magnetic pole 51c1 is arranged at three positions at 120-degree intervals along the circumferential direction CD about the axis X1, the second excitation magnetic pole 51c2 is arranged at three positions at 120-degree intervals along the circumferential direction CD about the axis X1, and the third excitation magnetic pole 51c3 is arranged at three positions at 120-degree intervals along the circumferential direction CD about the axis X1.

[0022] In this embodiment, the first excitation magnetic pole 51c1, the second excitation magnetic pole 51c2, and the third excitation magnetic pole 51c3 are provided corresponding to the three phases of U, V, and W, but other configurations are also possible. The excitation magnetic poles may be arranged at intervals along the circumferential direction CD so as to correspond to multiple phases other than the three phases.

[0023] The rotor 52 has a plurality of first magnetized portions 52a1 magnetized to N poles and a plurality of second magnetized portions 52a2 magnetized to S poles. The first magnetized portions 52a1 and the second magnetized portions 52a2 are alternately arranged along the circumferential direction CD about the axis X1.

[0024] The first bearing 60 is a member that supports one end of the rotor 52 that rotates about the axis X1 by the motor 50. An eccentric shaft that is disposed eccentrically with respect to the axis X1 is provided at the end of the rotor 52 on the scroll compression mechanism 40 side.

[0025] The second bearing portion 65 will now be described with reference to Figures 3 and 4. Figure 3 is a vertical cross-sectional view showing a schematic configuration of the scroll compressor 100 according to an embodiment of the present disclosure, illustrating a state before the scroll compressor 100 is assembled. Figure 4 is a cross-sectional view of the scroll compressor 100 shown in Figure 3 taken along the line B-B, with the front housing 30 omitted.

[0026] 3 and 4 , the second bearing 65 is a member that supports the tip end 52 a of the rotor 52 that rotates about the axis X1 by the motor 50. The second bearing 65 is fixed to the bottom 30 a of the front housing 30.

[0027] The inverter 70 is a device that generates a drive voltage for driving the motor 50 and controls the rotation speed of the motor 50 .

[0028] The gasket 80 is a member that is arranged between the end face 20a of the bearing housing 10 on the rear housing 20 side and the end face of the rear housing 20 on the bearing housing 10 side, and forms a sealing area to prevent refrigerant from leaking out from between the end face 10a and the end face 20a.

[0029] Next, a method for assembling the scroll compressor 100 of this embodiment will be described with reference to Fig. 5. Fig. 5 is a flowchart showing a method for assembling the scroll compressor 100 according to an embodiment of the present disclosure. The method for assembling the scroll compressor 100 of this embodiment is a method for changing the pre-assembly state of the scroll compressor 100 shown in Fig. 3 into the assembled state of the scroll compressor 100 shown in Fig. 1.

[0030] As shown in FIG. 3 , before assembly, the scroll compressor 100 is in a state in which the stator 51 is fixed inside the front housing 30 by shrink fitting, and the rotor 52 is removed from the front housing 30 .

[0031] In step S101, an operator attaches a fixing jig 110 to the rotor 52 to fix the rotational position of the rotor 52 about the axis X1 so as to prevent the rotor 52 from rotating about the axis X1 (fixing step). Note that the work of step S101 may be performed by an automatic attachment device (not shown) that attaches the fixing jig 110 to the rotor 52, rather than by an operator. In step S101, as shown in FIG. 2 , the rotational position of the rotor 52 about the axis X1 is fixed so that the positions of the multiple first magnetized portions 52a1 in the circumferential direction CD coincide with the position of the second exciting magnetic pole 51c2 in the circumferential direction CD.

[0032] In step S102, the operator operates current supply source 120 to start supplying magnetizing current to the plurality of second excitation magnetic poles 51c2 corresponding to phase V. In response to an instruction from the operator to start supplying magnetizing current, current supply source 120 starts supplying magnetizing current to the plurality of second excitation magnetic poles 51c2 via current supply line 121. The magnetizing current supplied from current supply source 120 magnetizes second excitation magnetic pole 51c2 to the N pole, which is the same polarity as first magnetized portion 52a1.

[0033] The instruction in step S102 may be given by a control device (not shown) rather than by an operator. The supply of the magnetizing current to the second exciting magnetic pole 51c2, which was started in step S102, is continued until it is stopped in step S104.

[0034] In step S103, the worker moves the rotor 52, whose rotational position has been fixed in step S101, along the axis X1 toward the front housing 30 so as to insert the rotor 52 into the stator 51 along the axis X1. For example, the worker moves the rotor 52 along the axis X1 toward the front housing 30 by operating a holding jig (not shown) that holds the rotor 52 on the axis X1. Note that the operation in step S103 may be performed by a control device (not shown) rather than by the worker.

[0035] 2, when the rotor 52 moves along the axis X1 toward the front housing 30, the position in the circumferential direction CD of the first magnetized portion 52a1 magnetized to the N pole is maintained by the fixing jig 110 so as to coincide with the position in the circumferential direction CD of the plurality of second excitation magnetic poles 51c2. The plurality of second excitation magnetic poles 51c2 are magnetic poles corresponding to the V phase magnetized to the N pole by the magnetizing current in step S102.

[0036] Since the position in the circumferential direction CD of the first magnetized portion 52a1 magnetized to the N pole matches the position in the circumferential direction CD of the second excitation magnetic pole 51c2 magnetized to the N pole, the rotor 52 receives uniform magnetic force (repulsive force) from the stator 51 toward the axis X1 at three points in the circumferential direction CD. Therefore, the rotor 52 does not come into contact with the stator 51 and is maintained so that its central axis is positioned on the axis X1.

[0037] In step S103, the operation of moving the rotor 52 along the axis X1 toward the front housing 30 is performed until the tip end 52 a of the rotor 52 is supported by the second bearing 65. When the tip end 52 a of the rotor 52 is supported by the second bearing 65, the operation of moving the rotor 52 along the axis X1 toward the front housing 30 is stopped.

[0038] In step S104, the operator operates the current supply source 120 to stop the supply of the magnetizing current to the plurality of second exciting magnetic poles 51c2 corresponding to phase V. In response to the operator's instruction to stop the supply of the magnetizing current, the current supply source 120 stops the supply of the magnetizing current to the plurality of second exciting magnetic poles 51c2 via the current supply line 121.

[0039] Through the above steps S101 to S104, the scroll compressor 100 is brought into the assembled state shown in Fig. 1. In the state shown in Fig. 1, the worker tightens the fastening bolts 90 into the fastening holes formed in the front housing 30, thereby fixing the bearing housing 10 in a state where it is sandwiched between the rear housing 20 and the front housing 30 along the axis X1, and the bearing housing 10, the rear housing 20, and the front housing 30 are integrated together.

[0040] The operation and effect of the assembling method of the scroll compressor 100 of this embodiment described above will be described. According to the assembling method of the scroll compressor 100 of this embodiment, the rotor 52, whose rotational position is fixed in the fixing step (step S101), is inserted into the stator 51 along the axis X1 in a state in which the position in the circumferential direction CD of the first magnetized portion 52a1, which has the same polarity as the V-phase second excitation magnetic pole 51c2 magnetized in the current supply step (steps S102 to S104), is aligned with the position in the circumferential direction CD of the V-phase second excitation magnetic pole 51c2. Because the first magnetized portion 52a1 of the same polarity (N pole) is aligned with the magnetized V-phase second excitation magnetic pole 51c2 in the circumferential direction CD, the rotor 52 is subjected to a uniform magnetic force (repulsive force) from the stator 51 toward the axis X1. Since the rotor 52 does not come into contact with the stator 51 and its central axis is maintained aligned with the axis X1, a method for assembling the scroll compressor 100 can be provided that can prevent the rotor 52 from coming into contact with the stator 51 when inserting the rotor 52 into the stator 51.

[0041] According to the assembly method of the scroll compressor 100 of this embodiment, if the position in the circumferential direction CD of the first magnetized portion 52a1, which has the same polarity as the V-phase second excitation magnetic pole 51c2 magnetized in the current supply step (steps S102 to S104), does not completely match the position in the circumferential direction CD of the V-phase second excitation magnetic pole 51c2, the rotor 52 does not receive an equal magnetic force from the stator 51 toward the axis X1, and the rotor 52 moves in a direction rotating around the axis X1 relative to the stator 51.

[0042] Here, in the current supply step (steps S102 to S104), the flow direction of the magnetizing current is switched so that the polarity of the V-phase second excitation magnetic pole 51c2 is temporarily reversed. This switching reverses the direction in which the rotor 52 rotates about the axis X1 relative to the stator 51, and the rotational position of the rotor 52 is pulled back. By repeating this operation, a state is created in which the position in the circumferential direction CD of the first magnetized portion 52a1, which has the same polarity as the V-phase second excitation magnetic pole 51c2 magnetized in the current supply step (steps S102 to S104), completely coincides with the position in the circumferential direction CD of the V-phase second excitation magnetic pole 51c2. In this state, the flow direction of the excitation current is switched again, so that the rotor 52 can receive a uniform magnetic force (repulsive force) from the stator 51 toward the axis X1.

[0043] According to the assembly method of the scroll compressor 100 of this embodiment, the rotational position of the rotor 52 is fixed so that the rotor 52 can oscillate within a predetermined rotational angle range. Therefore, when the flow direction of the magnetizing current is switched in the current supply step (steps S102 to S104) so ​​that the polarity of the V-phase second exciting magnetic pole 51c2 is temporarily reversed, the rotor 52 can be oscillated about the axis X1, thereby creating a state in which the position in the circumferential direction CD of the first magnetized portion 52a1, which has the same polarity as the V-phase second exciting magnetic pole 51c2 magnetized in the current supply step, completely coincides with the position in the circumferential direction CD of the V-phase second exciting magnetic pole 51c2.

[0044] In the above description, in steps S102 to S104, the magnetizing current is supplied to the plurality of second excitation magnetic poles 51c2 corresponding to the V phase, but other embodiments are also possible. For example, the magnetizing current may be supplied to the first excitation magnetic pole 51c1 corresponding to the U phase. Also, the magnetizing current may be supplied to the third excitation magnetic pole 51c3 corresponding to the W phase.

[0045] In the above description, in steps S102 to S104, a magnetizing current is supplied so as to magnetize the plurality of second excitation magnetic poles 51c2 corresponding to the V phase to N poles, but other configurations are also possible. For example, in steps S102 to S104, a magnetizing current may be supplied so as to magnetize the plurality of second excitation magnetic poles 51c2 corresponding to the V phase to S poles. In this case, in step S101, the rotational position of the rotor 52 about the axis X1 is fixed so that the positions in the circumferential direction CD of the plurality of second magnetized portions 52a2 magnetized to S poles coincide with the position in the circumferential direction CD of the second excitation magnetic poles 51c2.

[0046] In the above description, a magnetizing current is supplied to magnetize the plurality of second excitation magnetic poles 51c2 corresponding to the V phase to north poles, but other configurations are also possible. For example, in steps S102 to S104, in a state where a magnetizing current is supplied to magnetize the plurality of second excitation magnetic poles 51c2 corresponding to the V phase to north poles, the flow direction of the magnetizing current may be switched so that the plurality of second excitation magnetic poles 51c2 are temporarily magnetized to south poles. For example, it is preferable to switch the flow direction of the magnetizing current so that the plurality of second excitation magnetic poles 51c2 are temporarily magnetized to south poles at a frequency of 1 to 5 Hz.

[0047] When the flow direction of the magnetizing current is switched so that the plurality of second excitation magnetic poles 51c2 magnetized to N poles are temporarily magnetized to S poles, in step S101, the fixing jig 110 fixes the rotational position of the rotor 52 so that the rotor 52 can oscillate within a predetermined rotation angle range. As shown in Fig. 4, when the angle in the circumferential direction CD between adjacent teeth 51a along the circumferential direction CD is θ, the predetermined rotation angle at which the fixing jig 110 can oscillate the rotor 52 is preferably set to be equal to or greater than θ and equal to or less than 2θ.

[0048] The method for assembling the electric motor according to the present embodiment described above can be understood, for example, as follows: In the method for assembling the electric motor (100) according to the first aspect of the present disclosure, the electric motor includes a housing (10, 20, 30) formed in a cylindrical shape extending along an axis (X1), a motor (50) having a stator (51) arranged inside the housing so as to extend along the axis, and a rotor (52) arranged on the inner periphery of the stator, a drive unit (40) that is rotationally driven by the motor, and a bearing unit (65) that is fixed to a bottom portion (30a) of the housing and supports a tip end of the rotor, the stator having a plurality of excitation magnetic poles (51c1, 51c2, 51c3) corresponding to a plurality of excitation currents of phases, and the rotor having a plurality of first magnetized portions (52a1) magnetized to N poles and a plurality of second magnetized portions (52a2) magnetized to S poles. The first magnetized portions and the second magnetized portions are alternately arranged along the circumferential direction around the axis, and the method includes a fixing step (S101) of fixing a rotational position of the rotor so that the rotor does not rotate around the axis, a current supplying step (S102 to S104) of supplying a magnetizing current to the exciting magnetic pole of a predetermined phase included in the plurality of exciting magnetic poles, and an inserting step (S103) of inserting the rotor, whose rotational position has been fixed in the fixing step, into the stator along the axis in a state in which the circumferential position of either the first magnetized portion or the second magnetized portion, which has the same polarity as the exciting magnetic pole of the predetermined phase magnetized in the current supplying step, coincides with the circumferential position of the exciting magnetic pole of the predetermined phase, so that the tip end of the rotor is supported by the bearing.

[0049] According to a method for assembling an electric motor according to a first aspect of the present disclosure, the rotor, whose rotational position has been fixed in a fixing step, is inserted into a stator along the axis in a state in which the circumferential position of either the first magnetized portion or the second magnetized portion, which has the same polarity as the excitation magnetic pole of a predetermined phase magnetized in the current supply step, coincides with the circumferential position of the excitation magnetic pole of the predetermined phase. Because the first magnetized portion or the second magnetized portion, which has the same polarity as the magnetized excitation magnetic pole of the predetermined phase, is positioned in a position that coincides with the circumferential position, the rotor receives a uniform magnetic force (repulsive force) from the stator toward the axis. Because the rotor does not come into contact with the stator and its central axis is maintained aligned with the axis, a method for assembling an electric motor can be provided that prevents the rotor from coming into contact with the stator when the rotor is inserted into the stator.

[0050] A method of assembling an electric motor according to a second aspect of the present disclosure is the same as the first aspect, further including the following configuration: the current supply step switches the flow direction of the magnetizing current so that the polarity of the exciting magnetic pole of the predetermined phase is temporarily reversed.

[0051] According to the method for assembling an electric motor according to the second aspect of the present disclosure, if the circumferential position of either the first magnetized portion or the second magnetized portion, which has the same polarity as the exciting magnetic pole of a specified phase magnetized by the current supply process, does not perfectly match the circumferential position of the exciting magnetic pole of the specified phase, the rotor will not receive an equal magnetic force from the stator toward the axis, and the rotor will move in a direction rotating about the axis relative to the stator.

[0052] In the current supply step, the flow direction of the magnetizing current is switched so that the polarity of the exciting magnetic pole of the predetermined phase is temporarily reversed. This switching reverses the direction in which the rotor rotates about its axis relative to the stator, and the rotor's rotational position is pulled back. By repeating this operation, a state is created in which the circumferential position of either the first magnetized portion or the second magnetized portion, which has the same polarity as the exciting magnetic pole of the predetermined phase magnetized in the current supply step, completely coincides with the circumferential position of the exciting magnetic pole of the predetermined phase. In this state, the flow direction of the magnetizing current is switched again, allowing the rotor 52 to receive a uniform magnetic force (repulsive force) from the stator 51 toward the axis X1.

[0053] According to the electric motor assembly method of the third aspect of the present disclosure, in the second aspect, the method further includes the following configuration: the fixing step fixes the rotational position of the rotor so that the rotor can oscillate within a predetermined rotation angle range.

[0054] According to the method for assembling an electric motor according to the third aspect of the present disclosure, the rotational position of the rotor is fixed so that the rotor can oscillate within a predetermined rotation angle range. Therefore, when the flow direction of the magnetizing current is switched in the current supply step so that the polarity of the exciting magnetic pole of a predetermined phase is temporarily reversed, the rotor can be oscillated about its axis so that the circumferential position of either the first magnetized portion or the second magnetized portion, which has the same polarity as the exciting magnetic pole of the predetermined phase magnetized in the current supply step, gradually approaches a state in which it is completely aligned with the circumferential position of the exciting magnetic pole of the predetermined phase.

[0055] DESCRIPTION OF SYMBOLS 10 Bearing housing 20 Rear housing 30 Front housing 30a Bottom portion 40 Scroll compression mechanism (drive portion; compression portion) 41 Fixed scroll 42 Orbiting scroll 50 Motor 51 Stator 51a Teeth portion 51b Coil winding 51c1 First exciting magnetic pole 51c2 Second exciting magnetic pole 51c3 Third exciting magnetic pole 52 Rotor 52a Tip portion 52a1 First magnetized portion 52a2 Second magnetized portion 60 First bearing portion 65 Second bearing portion 70 Inverter 80 Gasket 90 Fastening bolt 100 Scroll compressor (electric motor) 110 Fixing jig 120 Current supply source 121 Current supply line CD Circumferential direction X1 Axial line

Claims

1. A method of assembling an electric motor, the electric motor comprising: a housing formed in a cylindrical shape extending along an axis; a motor having a stator arranged inside the housing to extend along the axis, and a rotor arranged on the inner periphery of the stator; a drive unit that is rotationally driven by the motor; and a bearing unit that is fixed to the bottom of the housing and supports a tip end of the rotor, the stator having a plurality of exciting magnetic poles corresponding to a plurality of phases of exciting current, the rotor having a plurality of first magnetized portions magnetized to N poles and a plurality of second magnetized portions magnetized to S poles, the first magnetized portions and the second magnetized portions being alternately arranged along the circumferential direction around the axis, the method comprising: a fixing step of fixing a rotational position of the rotor so that the rotor does not rotate around the axis; and a current supply step of supplying a magnetizing current to the exciting magnetic poles of a predetermined phase included in the plurality of exciting magnetic poles. and an insertion process of inserting the rotor, the rotational position of which is fixed in the fixing process, into the stator along the axis in a state in which the circumferential position of either the first magnetized portion or the second magnetized portion, which has the same polarity as the exciting magnetic pole of the specified phase magnetized in the current supplying process, coincides with the circumferential position of the exciting magnetic pole of the specified phase, so as to bring the tip end of the rotor into a state in which it is supported by the bearing portion.

2. A method for assembling an electric motor according to claim 1, wherein said current supplying step switches the flow direction of said magnetizing current so that the polarity of the exciting magnetic pole of said predetermined phase is temporarily reversed.

3. A method for assembling an electric motor as set forth in claim 2, wherein said fixing step fixes the rotational position of said rotor so that said rotor can oscillate within a range of a predetermined rotation angle.

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