Motor, blower, air conditioning device and method for manufacturing motor

Abstract

The electric motor comprises: an annular stator core, which is formed by connecting a plurality of core parts by a connecting part in the circumferential direction centered on an axis; a cover portion, which covers the stator core and includes a core peripheral portion surrounding the stator core from the radial outer side centered on the axis; and a rotor, which comprises a rotor core arranged on the radial inner side of the stator core and a magnet mounted on the rotor core, wherein the magnet constitutes a first magnetic pole and a part of the rotor core constitutes a second magnetic pole. The shortest radial distance R1 from the axis to the outer periphery of the core peripheral portion and the shortest radial distance R2 from the axis to the outer periphery of the stator core satisfy R1≥1.15×R2.

Description

Technical Field

[0001] The invention relates to a motor, a blower, an air conditioning device and a method for manufacturing the motor. Background Art

[0002] The electric motor has a rotor with magnets mounted on a rotor core and a stator surrounding the rotor. In recent years, an alternating-pole rotor has been developed in which the first magnetic pole is formed by the magnet and the second magnetic pole is formed by a part of the rotor core (for example, see Patent Document 1).

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: International Publication No. 2017 / 183162 (reference Figure 1 ) Summary of the invention

[0006] Problems to be solved by the invention

[0007] The alternating-pole rotor tends to have a larger outer diameter than the non-alternating-pole rotor, and the outer diameter of the stator tends to increase accordingly. Therefore, if the output of the motor is increased, the rigidity of the stator is insufficient, and the vibration and noise of the motor may increase.

[0008] The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to reduce vibration and noise of a motor having an alternating-pole rotor.

[0009] Solutions to Solve Problems

[0010] An electric motor according to one embodiment of the present invention comprises: an annular stator core, which is formed by connecting a plurality of core parts by a connecting part in a circumferential direction centered on an axis; a cover portion, which covers the stator core, and the cover portion includes a core peripheral portion, which surrounds the stator core from the radial outer side centered on the axis; and a rotor, which comprises: a rotor core, which is arranged on the radial inner side of the stator core; and a magnet, which is mounted on the rotor core, the magnet constituting a first magnetic pole, and a part of the rotor core constituting a second magnetic pole. The shortest radial distance R1 from the axis to the outer periphery of the core peripheral portion and the shortest radial distance R2 from the axis to the outer periphery of the stator core satisfy R1≥1.15×R2.

[0011] Effects of the Invention

[0012] According to the present invention, since the shortest distance R1 from the axis to the outer periphery of the core periphery and the shortest distance R2 from the axis to the outer periphery of the stator core satisfy R1≥1.15×R2, the stator core can be firmly held by the cover, thereby reducing vibration and noise of the motor having an alternating pole rotor. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a partial longitudinal sectional view showing the electric motor according to the first embodiment.

[0014] Figure 2 It is a top view showing the stator core in Embodiment 1.

[0015] Figure 3 This is a longitudinal sectional view showing the rotor in the first embodiment.

[0016] Figure 4 This is a cross-sectional view showing the rotor according to the first embodiment.

[0017] Figure 5 It is a rear view showing the electric motor in Embodiment 1.

[0018] Figure 6 It is a partial cross-sectional view showing the mold stator according to the first embodiment.

[0019] Figure 7 This is a graph showing the relationship between R1 / R2 and the noise level in the first embodiment.

[0020] Figure 8 This is a longitudinal sectional view showing a mold used in the manufacturing process of the electric motor according to the first embodiment.

[0021] Fig. 9 This is a flowchart showing the manufacturing process of the electric motor in the first embodiment.

[0022] Fig.10 It is a partial longitudinal sectional view showing the electric motor in the second embodiment.

[0023] Fig.11 This is a flowchart showing the manufacturing process of the electric motor in the second embodiment.

[0024] Fig.12 It is a partial cross-sectional view showing a molded stator of the electric motor according to the second embodiment.

[0025] Fig.13 This is a flowchart showing the manufacturing process of the electric motor in the second embodiment.

[0026] Fig.14 It is a partial cross-sectional view showing a molded stator of the electric motor according to the third embodiment.

[0027] Fig.15 (A) is a diagram showing an air-conditioning apparatus to which the electric motor according to each embodiment can be applied, and (B) is a cross-sectional view showing an outdoor unit of the air-conditioning apparatus. DETAILED DESCRIPTION

[0028] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the present invention is not limited to the embodiments.

[0029] Implementation Method 1

[0030] [Structure of the electric motor 1]

[0031] Figure 1 1 is a partial longitudinal sectional view showing the motor 1 in Embodiment 1. The motor 1 is used, for example, in a blower of an air conditioning device and is a brushless DC motor driven by an inverter. The motor 1 is an IPM (Interior Permanent Magnet) motor in which a magnet 25 is embedded in a rotor 2.

[0032] The electric motor 1 includes a rotor 2 having a shaft 11 as a rotation axis and a molded stator 50 surrounding the rotor 2. The molded stator 50 includes a stator 5 provided so as to surround the rotor 2 and a cover 40 covering the stator 5.

[0033] In the following description, the direction of the axis C1 as the central axis of the shaft 11 is referred to as the "axial direction". In addition, the circumferential direction centered on the axis C1 is referred to as the "circumferential direction". Figure 2 Indicated by arrow S. The radial direction centered on the axis C1 is referred to as the “radial direction.” A cross-sectional view of a section parallel to the axial direction is referred to as a “longitudinal cross-sectional view,” and a cross-sectional view of a section perpendicular to the axial direction is referred to as a “transverse cross-sectional view.”

[0034] The shaft 11 extends from the molded stator 50 to the Figure 1 The left side of the protrusion is protruded, and an impeller 505 (for example, a blower) is mounted on the mounting portion 11a formed on the protrusion. Fig.15 (A)). Therefore, the protruding side of the shaft 11 is referred to as a "load side", and the opposite side thereof is referred to as an "anti-load side".

[0035] [Structure of the molded stator 50]

[0036] As described above, the molded stator 50 includes the stator 5 and the cover 40. The stator 5 surrounds the rotor 2 from the radially outer side. The stator 5 includes the stator core 51, the insulating portion 52 provided on the stator core 51, and the coil 53 wound on the stator core 51 via the insulating portion 52.

[0037] The cover 40 is formed of a thermosetting resin such as BMC (bulk molding compound). Alternatively, it may be formed of a thermoplastic resin such as PBT (polybutylene terephthalate) or PPS (polyphenylene sulfide). The cover 40 has mounting legs 55 on its periphery. The mounting legs 55 are provided to mount the motor 1 on an air conditioning device.

[0038] The cover 40 has an opening 57 on the load side in the axial direction and a bearing support 58 on the opposite side of the load. The rotor 2 is inserted into the hollow portion inside the molded stator 50 from the opening 57. A metal bracket 15 is mounted on the opening 57. The bracket 15 holds a bearing 12 on one side of the support shaft 11. A waterproof cover 14 is mounted on the outside of the bracket 15 to prevent the intrusion of water or the like. The bearing support 58 of the cover 40 has a cylindrical inner peripheral surface, and the other bearing 13 on the support shaft 11 is held on the inner peripheral surface.

[0039] Figure 2 : is a top view showing the stator core 51. The stator core 51 is formed by stacking a plurality of stacked elements in the axial direction and fixing them together by riveting, welding or bonding. The stacked elements are, for example, electromagnetic steel plates. The stator core 51 has a yoke 511 extending in a ring shape in the circumferential direction centered on the axis C1 and a plurality of teeth 512 extending radially inward from the yoke 511. The tooth tip 513 on the radial inner side of the tooth 512 is aligned with the rotor 2 ( Figure 1 The number of teeth 512 is 12 here, but is not limited to this.

[0040] The stator core 51 has a structure divided into a plurality of core parts 51A for each tooth 512. The core part 51A is divided by a dividing surface part 514 formed on the yoke 511. The dividing surface part 514 extends radially outward from the inner peripheral surface of the yoke 511. A thin-walled part, i.e., a thin-walled connecting part 515, which is a plastically deformable thin-walled part, is formed between the terminal end of the dividing surface part 514 and the outer peripheral surface of the yoke 511.

[0041] The thin-walled connection portion 515 is a connection portion that connects the core portions 51A adjacent to each other in the circumferential direction. That is, the stator core 51 has a structure in which a plurality of core portions 51A are connected in the circumferential direction by the thin-walled connection portion 515. The stator core 51 can be expanded into a belt shape by plastic deformation of the thin-walled connection portion 515.

[0042] The coil 53 can be wound around the teeth 512 while the stator core 51 is expanded into a strip shape. After the coil 53 is wound, the strip-shaped stator core 51 is bent into a ring shape, and the ends W are welded to each other. In addition, the connecting portion connecting the adjacent core parts 51A is not limited to the thin-walled connecting portion 515, and may be a rivet portion, for example.

[0043] return Figure 1 The insulating portion 52 is formed of, for example, a thermoplastic resin such as PBT. The insulating portion 52 is formed by integrally molding a thermoplastic resin with the stator core 51 or by assembling a thermoplastic resin molded body to the stator core 51 .

[0044] The coil 53 is a magnetic wire wound around the teeth 512 ( Figure 2The insulating portion 52 has wall portions on the radially inner side and the radially outer side of the coil 53, respectively, to guide the coil 53 from both radial sides.

[0045] A wiring substrate 6 is arranged on one side in the axial direction relative to the stator 5. A drive circuit 60 such as a power transistor for driving the motor 1 and a magnetic sensor are mounted on the wiring substrate 6, and leads 61 are arranged. The leads 61 of the wiring substrate 6 are led out to the outside of the motor 1 from a lead-out portion 62 mounted on the outer peripheral portion of the cover portion 40.

[0046] [Structure of the rotor 2]

[0047] Figure 3 It is a longitudinal sectional view showing the rotor 2 . Figure 4 It is a longitudinal sectional view showing a part of the rotor 2 in an enlarged manner. Figure 4 Yes means Figure 3 A cross-sectional view of the rotor 2 is shown along line segment IV-IV.

[0048] like Figure 4 As shown, the rotor 2 includes: a shaft 11 as a rotating shaft; a rotor core 20 provided at a distance radially outside the shaft 11; a plurality of magnets 25 embedded in the rotor core 20; and a resin portion 3 provided between the shaft 11 and the rotor core 20. The number of the magnets 25 is 5 here. The magnets 25 are also called main magnets or rotor magnets.

[0049] The rotor core 20 is an annular member centered on the axis C1. The rotor core 20 has an outer periphery 20a and an inner periphery 20b, and the inner periphery 20b is spaced apart from the shaft 11 and faces the shaft 11. The rotor core 20 is formed by stacking a plurality of stacked elements in the axial direction and fixing them together by riveting, welding, or bonding. The stacked elements are, for example, electromagnetic steel plates with a thickness of 0.1 mm to 0.7 mm.

[0050] The rotor core 20 has a plurality of magnet insertion holes 21 in the circumferential direction. The magnet insertion holes 21 are arranged at equal intervals in the circumferential direction and at equal distances from the axis C1. The number of the magnet insertion holes 21 is 5. The magnet insertion holes 21 are formed along the outer circumference 20a of the rotor core 20 and penetrate the rotor core 20 in the axial direction.

[0051] A magnet 25 is inserted into each magnet insertion hole 21. The magnet 25 is in the shape of a flat plate, and the cross-sectional shape perpendicular to the axial direction is in the shape of a rectangle. The magnet 25 is a rare earth magnet, more specifically, a neodymium sintered magnet mainly composed of Nd (neodymium), Fe (iron) and B (boron). A magnetic shielding bridge 22 is formed as a gap at both ends of the magnet insertion hole 21 in the circumferential direction. The magnetic shielding bridge 22 suppresses the short circuit of the magnetic flux between adjacent magnets 25.

[0052] The five magnets 25 are arranged so that the same magnetic poles face the outer circumference of the rotor core 20. In the rotor core 20, magnetic poles opposite to those of the magnets 25 are formed in regions between the magnets 25 adjacent to each other in the circumferential direction.

[0053] Therefore, in the rotor 2, five first magnetic poles P1 and five second magnetic poles P2 are arranged alternately in the circumferential direction. The first magnetic poles P1 are formed by the magnets 25, and the second magnetic poles P2 are formed by the rotor core 20. Such a structure is called an alternating pole type.

[0054] Hereinafter, when simply referring to a "magnetic pole", both the first magnetic pole P1 and the second magnetic pole P2 are included. The number of poles of the rotor 2 is 10. The magnetic poles P1 and P2 of the rotor 2 are arranged at equal angular intervals in the circumferential direction with a pole pitch of 36 degrees (360 degrees / 10). The first magnetic pole P1 and the second magnetic pole P2 form an inter-pole space M.

[0055] The outer periphery 20a of the rotor core 20 has a so-called flower shape in a cross section perpendicular to the axial direction. In other words, the outer periphery 20a of the rotor core 20 has the largest outer diameter at the pole center of each of the magnetic poles P1 and P2, and the smallest outer diameter at the inter-pole M, and is arc-shaped from the pole center to the inter-pole M. The outer periphery 20a of the rotor core 20 is not limited to the flower shape, but may also be circular. The inner periphery 20b of the rotor core 20 has a circular shape in a cross section perpendicular to the axial direction.

[0056] In the alternating-pole rotor 2, the number of magnets 25 can be halved compared to a non-alternating-pole rotor having the same number of poles. Since the number of expensive magnets 25 is reduced, the manufacturing cost of the rotor 2 is reduced.

[0057] Here, the number of poles of the rotor 2 is set to 10, but the number of poles may be an even number of 4 or more. In addition, here, one magnet 25 is arranged in one magnet insertion hole 21 , but two or more magnets 25 may be arranged in one magnet insertion hole 21 .

[0058] The resin portion 3 is provided between the shaft 11 and the rotor core 20. The resin portion 3 is formed of a non-magnetic body to keep the shaft 11 and the rotor core 20 separated from each other. The resin portion 3 is preferably formed of a thermoplastic resin such as PBT.

[0059] The resin portion 3 includes an annular inner ring portion 31 in contact with the outer periphery of the shaft 11, an annular outer ring portion 33 in contact with the inner periphery 20b of the rotor core 20, and a plurality of ribs 32 connecting the inner ring portion 31 and the outer ring portion 33. The ribs 32 are arranged at equal intervals in the circumferential direction with the axis C1 as the center. The number of ribs 32 is, for example, half the number of poles, which is 5 in this case.

[0060] The shaft 11 is fitted inside the inner ring portion 31 of the resin portion 3. The ribs 32 are arranged at equal intervals in the circumferential direction and extend radially outward from the inner ring portion 31. A cavity portion 35 is formed between the ribs 32 adjacent to each other in the circumferential direction. Here, the number of ribs 32 is half the number of poles, and the circumferential position of the ribs 32 coincides with the pole center of the second magnetic pole P2, but is not limited to such a number and arrangement.

[0061] like Figure 3 As shown in FIG. 1 , a sensor magnet 26 is arranged so as to face the rotor core 20 in the axial direction. The sensor magnet 26 is held by the resin portion 3. The sensor magnet 26 has the same number of magnetic poles as the number of poles of the rotor 2. The magnetic field of the sensor magnet 26 is detected by a magnetic sensor mounted on the wiring substrate 6, thereby detecting the circumferential position of the rotor 2, that is, the rotational position.

[0062] [Structure of the Cover 40 Molding the Stator 50]

[0063] like Figure 1 As shown, the cover portion 40 includes a core peripheral portion 41 surrounding the stator core 51 from the radially outer side and core adjacent portions 42, 43 protruding in the axial direction to both sides of the stator core 51. The core peripheral portion 41 includes the above-mentioned mounting legs 55.

[0064] The core adjacent portion 42 is located on the load side of the core surrounding portion 41. Figure 1 The core adjacent portion 42 is a portion covering the insulating portion 52 and the coil 53 protruding from the axial end surface of the stator core 51 , and has the above-mentioned opening portion 57 .

[0065] The core adjacent portion 43 is located on the opposite side of the core surrounding portion 41 from the load side. Figure 1 The core adjacent portion 43 is a portion that covers the insulating portion 52 protruding from the axial end surface of the stator core 51 , the coil 53 , and the wiring substrate 6 , and has the bearing support portion 58 described above.

[0066] The shortest radial distance from the axis C1 to the outer periphery of the core peripheral portion 41 is set to R1. Here, the outer periphery of the core peripheral portion 41 is cylindrical, but it can also have a tapered shape. In addition, the shortest radial distance from the axis C1 to the outer periphery of the stator core 51 is set to R2. R1 and R2 satisfy R1≥1.15×R2.

[0067] The minimum radial thickness of the core peripheral portion 41 is set to T1. The minimum thickness T1 is the shortest radial distance between the outer periphery of the core peripheral portion 41 and the outer periphery of the stator core 51. Here, the radial thickness of the core peripheral portion 41 is constant in the axial direction except for the mounting legs 55, but the thickness may vary in the axial direction.

[0068] The minimum radial thickness of the core adjacent portions 42 and 43 is set to T2. The minimum thickness of the core adjacent portion 42 is the shortest radial distance between the outer periphery of the core adjacent portion 42 and the component covered by the core adjacent portion 42. Here, the outer periphery of the core adjacent portion 42 has a tapered shape, and the outer diameter of the core adjacent portion 42 decreases as it moves away from the core surrounding portion 41 in the axial direction. Therefore, the minimum thickness T2 of the core adjacent portion 42 becomes the radial distance between the outer periphery of the core adjacent portion 42 and the protruding end of the insulating portion 52.

[0069] The minimum thickness of the core adjacent portion 43 is the shortest distance in the radial direction between the outer periphery of the core adjacent portion 43 and the component covered by the core adjacent portion 43. The outer diameter of the core adjacent portion 43 is larger than the outer diameter of the core adjacent portion 42. Therefore, the minimum thickness T2 of the portion including the core adjacent portions 42 and 43 becomes the radial distance between the outer periphery of the core adjacent portion 42 and the protruding end of the insulating portion 52.

[0070] Figure 5 is from Figure 1 The figure shows the motor 1 viewed from the direction indicated by the arrow V, i.e., a rear view. Figure 6 Yes means Figure 1 A partial cross-sectional view of the molded stator 50 in the plane indicated by the middle line segment VI to VI. Figure 6 , the cover portion 40 in the molded stator 50 is shown in cross section.

[0071] like Figure 5 As shown, the molded stator 50 has an annular outer periphery centered on the axis, and is formed with mounting legs 55 protruding radially outward from the outer periphery. In this example, four mounting legs 55 are formed at 90-degree intervals in the circumferential direction. However, the number of mounting legs 55 is arbitrary. A hole 56 is formed in the mounting leg 55 for inserting a fixing member for mounting the motor 1 on the air conditioning device.

[0072] like Figure 6 As shown, the core surrounding portion 41 of the cover portion 40 is arranged in an annular shape so as to surround the stator core 51 from the radial outside, and also has the above-mentioned mounting legs 55. The core surrounding portion 41 has a first portion 411 located radially outside the thin-walled connecting portion 515 of the stator core 51 and a second portion 412 located radially outside the teeth 512 of the stator core 51.

[0073] The first parts 411 and the second parts 412 are alternately arranged in the circumferential direction. The number of the first parts 411 and the number of the second parts 412 are the same as the number of the teeth 512, which is 12. The above-mentioned mounting legs 55 are formed on the radial outer sides of four of the 12 first parts 411.

[0074] The first portion 411 may have any circumferential width as long as it is located radially outside the thin-walled connection portion 515. Similarly, the second portion 412 may have any circumferential width as long as it is located radially outside the teeth 512.

[0075] In the core peripheral portion 41 , the maximum radial thickness of the first portion 411 is A1. The maximum thickness A1 of the first portion 411 is the maximum distance from the outer periphery of the stator core 51 to the outer periphery of the first portion 411 , and is the distance from the outer periphery of the stator core 51 to the outer periphery of the mounting leg 55 .

[0076] The maximum thickness of the second portion 412 in the radial direction is defined as A2. The maximum thickness A2 of the second portion 412 is the maximum distance from the outer periphery of the stator core 51 to the outer periphery of the second portion 412. The maximum thickness A1 of the first portion 411 is thicker than the maximum thickness A2 of the second portion 412.

[0077] The shortest distance R1 from the axis C1 to the outer periphery of the core peripheral portion 41, the shortest distance R2 from the axis C1 to the outer periphery of the stator core 51, and the maximum thickness A1 of the first portion 411 satisfy R2+A1≥R1. That is, the first portion 411 including the mounting legs 55 protrudes radially outward from other portions of the core peripheral portion 41.

[0078] Figure 7 The graph shows the relationship between the ratio R1 / R2 of the shortest distance R1 from the axis C1 to the outer periphery of the core peripheral portion 41 and the shortest distance R2 from the axis C1 to the outer periphery of the stator core 51 and the noise level. The noise level is expressed as a relative value relative to the reference value, with the noise level when R1 / R2=1.07 as the reference value.

[0079] like Figure 7 As shown in FIG. 1 , as R1 / R2 increases, the noise level decreases. This is because the cover 40 can firmly hold the stator core 51 by increasing the outer diameter of the cover 40 relative to the outer diameter of the stator core 51 .

[0080] When R1 / R2 is 1.15 or more, the noise level decreases slowly. That is, the point where R1 / R2=1.15 is equivalent to the inflection point of the curve. In addition, if R1 / R2 exceeds 1.20, the noise level is constant. Therefore, it can be seen that in order to fully suppress noise, it is preferred that R1 / R2 is 1.15 or more.

[0081] The stator core 51 has a structure in which a plurality of core parts 51A are connected by a thin-walled connecting part 515, and therefore has a lower strength than an integrated stator. The shortest distance R1 from the axis C1 to the outer periphery of the core peripheral part 41 and the shortest distance R2 from the axis C1 to the outer periphery of the stator core 51 satisfy R1 ≥ 1.15 × R2, so that the cover part 40 can firmly hold the stator core 51. Thus, the deformation of the stator core 51 can be suppressed, and the vibration and noise of the motor 1 can be reduced.

[0082] Furthermore, if the shortest distance R1 from the axis C1 to the outer periphery of the core peripheral portion 41 and the shortest distance R2 from the axis C1 to the outer periphery of the stator core 51 satisfy R1 ≥ 1.20×R2, vibration and noise of the motor 1 can be further suppressed.

[0083] In addition, as described above, in the core peripheral portion 41, the maximum thickness A1 of the first portion 411 is thicker than the maximum thickness A2 of the second portion 412. In the stator core 51, the thin-walled connecting portion 515 is a portion with low strength, but by thickening the maximum thickness A1 of the first portion 411 located radially outside the thin-walled connecting portion 515, deformation of the stator core 51 can be suppressed, and vibration and noise of the motor 1 can be reduced.

[0084] It should be noted that if the entire first portion 411 of the core peripheral portion 41 has the maximum thickness A1, the effect of reducing the vibration and noise of the motor 1 can be further improved, but if a part of the first portion 411 has the maximum thickness A1, the vibration and noise of the motor 1 can be reduced to a certain extent.

[0085] In addition, as described above, the shortest distance R1 from the axis C1 to the outer periphery of the core peripheral portion 41, the shortest distance R2 from the axis C1 to the outer periphery of the stator core 51, and the maximum thickness A1 of the first portion 411 of the cover portion 40 satisfy R2+A1≥R1. That is, the first portion 411 protrudes radially outward more than other portions of the core peripheral portion 41. Therefore, compared with the case where the core peripheral portion 41 is enlarged as a whole in the radial direction, the amount of material used can be reduced, the deformation of the stator core 51 can be suppressed, and the vibration and noise of the motor 1 can be reduced.

[0086] As described above, since the minimum thickness T1 of the core peripheral portion 41 is thicker than the minimum thickness T2 of the core adjacent portions 42 , 43 , deformation of the stator core 51 can be suppressed by the core peripheral portion 41 , and the amount of material used to form the cover portion 40 can be reduced.

[0087] [Manufacturing method of electric motor 1]

[0088] Next, a method for manufacturing the electric motor 1 will be described. First, a mold 200 used in a manufacturing process of the stator 5 will be described. Figure 8Schematic diagram showing a mold 200 used in the molding step.

[0089] The mold 200 is configured to include an upper mold 201 and a lower mold 202 that can be opened and closed, and a cavity 204 as a hollow portion is formed between the upper mold 201 and the lower mold 202. A runner 206 is formed between the upper mold 201 and the lower mold 202 as a flow path for injecting resin into the cavity 204. The runner 206 is connected to the upper end portion of the cavity 204.

[0090] The lower mold 202 is formed with a cylindrical core 203 protruding into the cavity 204. The core 203 engages with the inner side of the stator 5. A large diameter portion 207 extending radially outward from the core 203 is formed at the lower end of the core 203. The large diameter portion 207 is aligned with the opening 57 ( Figure 1 ) corresponding part.

[0091] Fig. 9 1 is a flowchart showing the manufacturing process of the motor 1. First, the stacking elements are stacked and fixed together by caulking or the like to form the stator core 51 (step S101). At this stage, the plurality of core portions 51A of the stator core 51 are not bent into a ring shape but expanded into a belt shape.

[0092] Next, a thermoplastic resin molded body is attached to the stator core 51, or a thermoplastic resin is integrally molded with the stator core 51, thereby forming the insulating portion 52. Thereafter, the coil 53 is wound around the teeth 512 of the stator core 51 via the insulating portion 52, and the plurality of core portions 51A of the stator core 51 are bent into a ring shape and the ends W are welded (step S102).

[0093] Next, wiring board 6 is mounted on insulating portion 52 of stator core 51, and motor 1 and wiring board 6 are electrically connected (step S103). Thus, stator 5 including stator core 51, insulating portion 52, coil 53, and wiring board 6 is manufactured.

[0094] Next, the stator 5 is arranged at Figure 8 The mold 200 shown molds the cover 40 with resin (step S104). Specifically, the upper mold 201 is moved upward to open the cavity 204, and the stator 5 is arranged in the cavity 204. The lead portion 62 of the stator 5 protrudes to the outside of the cavity 204.

[0095] Then, the upper mold 201 is moved downward to close the cavity 204, and a resin such as BMC is injected into the cavity 204 from the runner 206 and cured. When a thermosetting resin is used, after the resin is injected into the cavity 204, the mold 200 is heated to cure the resin.

[0096] The resin cured in the cavity 204 becomes the cover portion 40 covering the stator 5. Thus, the molded stator 50 is formed. The resin is not limited to a thermosetting resin, and may be, for example, a thermoplastic resin.

[0097] On the other hand, the rotor 2 is manufactured as follows. First, the stacked elements are stacked and fixed together by riveting or the like to form the rotor core 20, and the magnet 25 is inserted into the magnet insertion hole 21 of the rotor core 20. Then, the rotor core 20 is placed in a rotor mold together with the shaft 11 and the sensor magnet 26, and resin is injected into the mold and cured to form the resin portion 3. Thus, the rotor 2 ( Figure 3 ).

[0098] Then, bearings 12 and 13 are mounted on shaft 11 of rotor 2, and rotor 2 is inserted into molded stator 50 from opening 57. Bracket 15 and waterproof cover 14 are mounted to opening 57 of molded stator 50 (step S105). Thus, manufacture of motor 1 is completed.

[0099] [Effects of Embodiment]

[0100] As described above, the motor 1 of the first embodiment includes: an annular stator core 51 formed by connecting a plurality of core portions 51A in the circumferential direction; and a cover portion 40 including a core peripheral portion 41 surrounding the stator core 51 from the radially outer side. The rotor 2 includes a rotor core 20 disposed radially inside the stator core 51 and a magnet 25 mounted on the rotor core 20, the magnet 25 constituting a first magnetic pole P1, and a portion of the rotor core 20 constituting a second magnetic pole P2. In addition, the shortest radial distance R1 from the axis C1 to the outer periphery of the core peripheral portion 41 and the shortest radial distance R2 from the axis C1 to the outer periphery of the stator core 51 satisfy R1 ≥ 1.15 × R2. Therefore, the stator core 51 can be firmly held by the cover portion 40, thereby suppressing deformation of the stator core 51 and reducing vibration and noise of the motor 1.

[0101] In addition, since the minimum thickness T1 of the core surrounding portion 41 surrounding the stator core 51 is thicker than the minimum thickness T2 of the core adjacent portions 42 and 43 protruding axially beyond the stator core 51, the amount of material used to constitute the cover portion 40 can be reduced, and the deformation of the stator core 51 can be suppressed, thereby reducing the vibration and noise of the motor 1.

[0102] In addition, in the cover portion 40, since the radial maximum thickness A1 of the first portion 411 located radially outside the thin-walled connecting portion 515 of the stator core 51 and the above-mentioned shortest distances R1 and R2 satisfy R2+A1>R1, the amount of material used to constitute the cover portion 40 can be reduced, and the effect of suppressing the deformation of the stator core 51 and the effect of reducing the vibration and noise of the motor 1 can be improved.

[0103] In addition, in the cover portion 40, since the radial maximum thickness A1 of the first portion 411 located radially outside the thin-walled connecting portion 515 of the stator core 51 and the radial maximum thickness A2 of the second portion 412 located radially outside the tooth 512 satisfy A1>A2, the thin-walled connecting portion 515 of the stator core 51 can be particularly firmly maintained, thereby improving the effect of suppressing deformation of the stator core 51.

[0104] In addition, the maximum thickness A2 of the second portion 412 located radially outside the tooth 512 is the narrowest in the thickness of the core peripheral portion 41, thereby reducing the amount of material used to constitute the cover portion 40, thereby improving the effect of suppressing deformation of the stator core 51 and reducing vibration and noise of the motor 1.

[0105] In addition, the cover portion 40 has mounting legs 55 radially outside the thin-walled connecting portion 515, so that the stator core 51 can be firmly held by the mounting legs 55 for mounting the motor 1 on the air conditioning device. This can improve the effect of suppressing deformation of the stator core 51 and the effect of reducing vibration and noise of the motor 1.

[0106] Implementation Method 2

[0107] Next, the electric motor 1 according to the second embodiment will be described. Fig.10 1 is a partial longitudinal sectional view of the motor 1 of the second embodiment. In the motor 1 of the second embodiment, the core surrounding portion 41A and the core adjacent portions 42A and 43A of the cover portion 40A of the molded stator 50 are made of materials having different mechanical properties. The core surrounding portion 41A is also referred to as the first component, and the core adjacent portions 42A and 43A are also referred to as the second component. The mechanical properties refer to strength such as tensile strength, for example.

[0108] The core peripheral portion 41A is preferably made of a material having a particularly high strength in order to hold the stator core 51. On the other hand, the core adjacent portions 42A and 43A cover components having complex shapes such as the wiring substrate 6, the lead portion 62, and the insulating portion 52, and are therefore preferably made of a material having high fluidity during molding.

[0109] The core surrounding portion 41A and the core adjacent portions 42A and 43A can be formed of a thermosetting resin such as BMC, for example. As an example, BMC contains 20% by weight of unsaturated polyester, 70% by weight of fillers such as calcium carbonate or calcium hydroxide, 5 to 7% by weight of crosslinking agents such as styrene monomers, and 2 to 3% by weight of additives such as release agents or coloring pigments.

[0110] In this embodiment 2, the core surrounding portion 41A of the cover portion 40A is made of a material obtained by adding reinforcing materials such as glass fiber to the above-mentioned BMC. The amount of reinforcing material added is, for example, 5% by weight. On the other hand, the core adjacent portions 42A and 43A are made of BMC without reinforcing materials added. Thus, the stator core 51 can be firmly held by the core surrounding portion 41A, and the components such as the wiring substrate 6 can be covered without gaps by the core adjacent portions 42A and 43A. That is, the vibration and noise of the motor 1 can be suppressed, and the quality of the motor 1 can be improved.

[0111] In addition, the core peripheral portion 41A and the core adjacent portions 42A and 43A may also be formed of thermoplastic resins such as PBT (polybutylene terephthalate) and PPS (polyphenylene sulfide). Generally, the strength of PPS is higher than that of PBT, so the core peripheral portion 41A may be formed of PPS, and the core adjacent portions 42A and 43A may be formed of PBT.

[0112] Alternatively, the core surrounding portion 41A may be formed of a thermoplastic resin to which a reinforcing material such as glass fiber is added. The amount of the reinforcing material added is, for example, 15 to 50% by weight. In this case, the core adjacent portions 42A and 43A may be formed of a thermoplastic resin to which no reinforcing material is added.

[0113] Alternatively, at least one of the core peripheral portion 41A and the core adjacent portions 42A, 43A may be formed of a material other than resin. For example, the core peripheral portion 41A may be formed of a die-cast aluminum body, and the core adjacent portions 42A, 43A may be formed of the above-mentioned thermosetting resin or thermoplastic resin.

[0114] In addition, the core surrounding portion 41A has the function of reinforcing the stator 5, and thus may be formed of a thermoplastic resin to which a reinforcing material such as glass fiber is added. In addition, the core adjacent portions 42A and 43A include the bearing support portion 58 and the like, and thus may be formed of a thermosetting resin that is easy to obtain high dimensional accuracy. That is, a thermoplastic resin and a thermosetting resin may be used in combination.

[0115] The motor 1 according to the second embodiment is configured similarly to the motor 1 according to the first embodiment except for the above-mentioned points.

[0116] Fig.11 This is a flowchart showing the manufacturing process of the electric motor 1 according to the second embodiment. The process of manufacturing the stator 5 (steps S101 to S103 ) is the same as that of the first embodiment.

[0117] In this second embodiment, the core surrounding portion 41A and the core adjacent portions 42A and 43A of the cover portion 40A are made of different materials, so three moldings are performed. In the first molding, the stator 5 is arranged in a first mold having a cavity in a region corresponding to the core adjacent portion 42A, and, for example, BMC without reinforcing material is injected into the mold and heated (step S104A). Thus, the core adjacent portion 42A covering the load side of the stator 5 is formed.

[0118] Next, the stator 5 is arranged in a second mold having a cavity in a region corresponding to the core peripheral portion 41A, and for example, BMC with added reinforcement material is injected into the mold and heated (step S104B). Thus, the core peripheral portion 41A covering the stator core 51 is formed adjacent to the core adjacent portion 42A.

[0119] Next, the stator 5 is arranged in a third mold having a cavity in a region corresponding to the core adjacent portion 43A, and, for example, BMC without reinforcing material is injected into the mold and heated (step S104C). Thus, the core adjacent portion 43A covering the opposite side of the stator 5 on the load side is formed adjacent to the core surrounding portion 41A.

[0120] In this way, the molded stator 50 is formed. Then, as described in the first embodiment, the rotor 2 is inserted into the molded stator 50, and the bracket 15 and the waterproof cover 14 are attached to the molded stator 50 (step S105). Thus, the manufacture of the motor 1 is completed.

[0121] Here, the manufacturing process is described in which the core surrounding portion 41A and the core adjacent portions 42A and 43A are formed of a thermosetting resin, but the core surrounding portion 41A and the core adjacent portions 42A and 43A may be formed of a thermoplastic resin. In this case, in steps S104A to S104C, instead of injecting the resin into the mold and curing it by heating, the resin that has been molten by heating is injected into the mold and cured by cooling.

[0122] In addition, Fig.11 In the manufacturing process shown, the core surrounding portion 41A and the core adjacent portions 42A and 43A are formed by three steps of steps S104A to S104C, but the manufacturing process is not limited to this. For example, if the core surrounding portion 41A is formed in step S104A, and the core adjacent portions 42A and 43A are simultaneously formed on both axial sides of the core surrounding portion 41A, the core surrounding portion 41A and the core adjacent portions 42A and 43A can be formed in two steps.

[0123] As described above, in the second embodiment, the core surrounding portion 41A and the core adjacent portions 42A and 43A of the cover portion 40A that molds the stator 50 are made of materials having different mechanical properties, so the stator core 51 can be firmly held by the core surrounding portion 41A, and the wiring substrate 6 and the like can be covered without a gap by the core adjacent portions 42A and 43A. Therefore, the vibration and noise of the motor 1 can be reduced, and the performance of the motor 1 can be further improved.

[0124] Furthermore, since the core surrounding portion 41A and the core adjacent portions 42A and 43A are made of a material containing resin, the core surrounding portion 41A and the core adjacent portions 42A and 43A having different mechanical properties can be manufactured by relatively simple processes.

[0125] In particular, by forming at least one of the core surrounding portion 41A and the core adjacent portions 42A, 43A from a material containing a thermosetting resin or a material containing a thermoplastic resin, molding using a plurality of molds can be performed as described above, and the manufacturing process can be further simplified.

[0126] Implementation 3

[0127] Next, the electric motor 1 according to the third embodiment will be described. Fig.12 1 is a partial cross-sectional view showing a molded stator 50 of the electric motor 1 according to the third embodiment. The core surrounding portion 41B of the cover portion 40B according to the third embodiment includes an annular first component 45 surrounding the stator core 51 from the radially outer side and an annular second component 46 further surrounding the first component 45 from the radially outer side. The first component 45 and the second component 46 are made of materials having different mechanical properties. The mechanical properties refer to strength such as tensile strength, for example.

[0128] First component 45 is preferably made of a material having particularly high strength in order to hold stator core 51. Second component 46 is provided radially outside first component 45 and is required to be lower in strength than first component 45, so is preferably made of a low-cost material.

[0129] The first component 45 and the second component 46 can be made of a thermosetting resin such as BMC. That is, the first component 45 can be made of a material in which a reinforcing material such as glass fiber is added to a thermosetting resin, similarly to the core surrounding portion 41A of Embodiment 2. The second component 46 can be made of a thermosetting resin without adding a reinforcing material, similarly to the core adjacent portions 42A and 43A of Embodiment 2.

[0130] Furthermore, the first component 45 and the second component 46 may be made of thermoplastic resin such as PBT or PPS. Specifically, the first component 45 may be made of a thermoplastic resin with a reinforcing material added thereto, and the second component 46 may be made of a thermoplastic resin without a reinforcing material added thereto.

[0131] Alternatively, at least one of the first component 45 and the second component 46 may be formed of a material other than resin. For example, the first component 45 may be formed of a die-cast aluminum body, and the second component 46 may be formed of the above-mentioned thermosetting resin or thermoplastic resin.

[0132] In addition, Fig.12 FIG. 4 shows the core surrounding portion 41B of the cover portion 40B, but the core adjacent portions 42, 43 ( Figure 1 ) can be formed in the same manner as in Embodiment 1 or Embodiment 2. In terms of ease of forming, it is preferred that the core adjacent portions 42 and 43 of the cover portion 40B are integrally formed with the first component 45 using the same material as the first component 45.

[0133] The motor 1 according to the third embodiment is configured similarly to the motor 1 according to the first embodiment except for the above-mentioned points.

[0134] Fig.13 1 is a flowchart showing a manufacturing process of the electric motor 1 according to the third embodiment. The process of manufacturing the stator 5 (steps S101 to S103 ) is the same as that of the first embodiment.

[0135] In the third embodiment, since the first component 45 and the second component 46 of the cover 40B are made of different materials, two moldings are performed. In the first molding, the stator 5 is arranged in a first mold having a cavity in a region corresponding to the first component 45, and, for example, BMC to which a reinforcing material is added is injected into the mold and heated (step S104D). Thus, the first component 45 covering the stator core 51 and the core adjacent portions 42, 43 ( Figure 1 ).

[0136] Next, the stator 5 is arranged in a second mold having a cavity in a region corresponding to the second component 46, and for example, BMC without reinforcing material is injected into the mold and heated (step S104E). Thus, the second component 46 covering the first component 45 from the radial outside is formed.

[0137] In this way, the molded stator 50 is formed. Then, as described in the first embodiment, the rotor 2 is inserted into the molded stator 50, and the bracket 15 and the waterproof cover 14 are attached to the molded stator 50 (step S105). Thus, the manufacture of the motor 1 is completed.

[0138] Here, the manufacturing process is described in the case where the first component 45 and the second component 46 are composed of a thermosetting resin, but the first component 45 and the second component 46 may be composed of a thermoplastic resin. In this case, in steps S104D to S104E, instead of injecting the resin into the mold and curing it by heating, the resin that has been molten by heating is injected into the mold and cured by cooling.

[0139] As described above, in the third embodiment, the first component 45 and the second component 46 of the cover portion 40B that molds the stator 50 are made of materials having different mechanical properties, so the stator core 51 can be firmly held by the first component 45, and the second component 46 can be made of a low-cost material. This can reduce vibration and noise of the motor 1, and can reduce manufacturing costs.

[0140] Furthermore, since both the first component portion 45 and the second component portion 46 are made of a material including a resin, the first component portion 45 and the second component portion 46 having different mechanical properties can be formed by a relatively simple manufacturing method.

[0141] In particular, when the first component 45 and the second component 46 are made of a material containing a thermosetting resin or a material containing a thermoplastic resin, molding using a plurality of molds can be performed as described above, and the manufacturing process can be further simplified.

[0142] Implementation 4

[0143] Next, the electric motor 1 according to the fourth embodiment will be described. Fig.14 1 is a partial cross-sectional view showing a molded stator 50 of the electric motor 1 according to Embodiment 4. The core surrounding portion 41C of the cover portion 40C according to Embodiment 4 includes a first component portion 47 located radially outside the thin-walled connecting portion 515 of the stator core 51 and a second component portion 48 located radially outside the teeth 512 of the stator core 51. The first component portion 47 and the second component portion 48 are made of materials having different mechanical properties. The mechanical properties refer to strength such as tensile strength, for example.

[0144] The first component 47 is preferably made of a material with particularly high strength because it maintains the thin-walled connection portion 515 with low strength in the stator core 51. On the other hand, the second component 48 is a portion with high strength in the stator core 51, and is required to be lower in strength than the first component 47, and is preferably made of a low-cost material.

[0145] The first component 47 and the second component 48 can be made of a thermosetting resin such as BMC. That is, the first component 47 can be made of a material in which a reinforcing material such as glass fiber is added to a thermosetting resin, similarly to the core surrounding portion 41A of Embodiment 2. In addition, the second component 48 can be made of a thermosetting resin without adding a reinforcing material, similarly to the core adjacent portions 42A and 43A of Embodiment 2.

[0146] In addition, the first component 47 and the second component 48 may also be made of a thermoplastic resin such as PBT or PPS. Specifically, the first component 47 may be made of a material obtained by adding a reinforcing material such as glass fiber to a thermoplastic resin. In addition, the second component 48 may be made of a thermoplastic resin without adding a reinforcing material.

[0147] Alternatively, at least one of the first component 47 and the second component 48 may be formed of a material other than resin. For example, the first component 47 may be formed of a die-cast aluminum body, and the second component 48 may be formed of the above-mentioned thermosetting resin or thermoplastic resin.

[0148] In addition, Fig.14 The core surrounding portion 41C of the cover portion 40C is shown in FIG. 4 , but the core adjacent portions 42, 43 ( Figure 1 ) can be formed in the same manner as in Embodiment 1 or Embodiment 2.

[0149] The motor 1 according to the fourth embodiment is configured similarly to the motor 1 according to the first embodiment except for the above-mentioned points.

[0150] As described above, in the fourth embodiment, the first component 47 and the second component 48 of the cover portion 40C that molds the stator 50 are made of materials having different mechanical properties, so the stator core 51 can be firmly held by the first component 47, and the second component 48 can be made of a low-cost material. As a result, the vibration and noise of the motor 1 can be reduced, and the manufacturing cost can be reduced.

[0151] [Air conditioning device]

[0152] Next, an air conditioning apparatus to which the electric motor 1 according to the above-described first to fourth embodiments can be applied will be described. Fig.15 (A) is a diagram showing a configuration of an air-conditioning apparatus 500 to which the electric motor 1 according to Embodiment 1 is applied. The air-conditioning apparatus 500 includes an outdoor unit 501 , an indoor unit 502 , and a refrigerant pipe 503 connecting these.

[0153] The outdoor unit 501 includes an outdoor blower 510 such as a propeller fan, and the indoor unit 502 includes an indoor blower 520 such as a cross flow fan. The outdoor blower 510 includes an impeller 505 and a motor 1 for driving the impeller 505. The indoor blower 520 includes an impeller 521 and a motor 1 for driving the impeller 521. The motor 1 has the same structure as described in Embodiment 1. Fig.15 (A) also shows a compressor 504 for compressing the refrigerant.

[0154] Fig.15 (B) is a cross-sectional view of the outdoor unit 501. The electric motor 1 is supported by a frame 509 disposed in a housing 508 of the outdoor unit 501. An impeller 505 is attached to the shaft 11 of the electric motor 1 via a hub 506.

[0155] In the outdoor blower 510, the impeller 505 rotates by the rotation of the rotor 2 of the motor 1, and blows air outdoors. Similarly, in the indoor blower 520, the impeller 521 rotates by the rotation of the rotor 2 of the motor 1, and blows air indoors.

[0156] During cooling operation, the heat generated when the refrigerant is condensed in the condenser is released outdoors by the air supplied by the outdoor blower 510. In addition, the air from which the heat has been removed by the evaporator is supplied indoors by the indoor blower 520.

[0157] The motor 1 of the first embodiment has a structure that reduces vibration and noise, and thus can improve the quietness of the air conditioning device 500. In addition, the motor 1 of any of the second to fourth embodiments may be used instead of the motor 1 of the first embodiment. In addition, here, the motor 1 is used as the driving source of the outdoor blower 510 and the driving source of the indoor blower 520, respectively, but it is sufficient as long as the driving source of at least one of the blowers uses the motor 1.

[0158] Furthermore, the electric motor 1 described in the first to fourth embodiments can also be mounted on electrical equipment other than the blower of the air-conditioning apparatus.

[0159] As mentioned above, although the preferred embodiment of the present invention has been described in detail, the present invention is not limited to the above-mentioned embodiment, and various improvements or modifications can be made without departing from the gist of the present invention.

[0160] Description of Reference Numerals

[0161] 1 motor, 2 rotor, 3 resin portion, 5 stator, 6 wiring board, 11 shaft, 12, 13 bearings, 15 bracket, 20 rotor core, 21 magnet insertion hole, 22 magnetic shielding bridge, 25 magnet, 26 sensor magnet, 40 cover portion, 41 core surrounding portion, 41A core surrounding portion (first component), 42 core adjacent portion, 42A core adjacent portion (second component), 43 core adjacent portion, 43A core adjacent portion (second component), 45, 47 first component, 46, 48 Two components, 50 molded stator, 51 stator core, 51A core part, 52 insulating part, 53 coil, 55 mounting leg, 200 mold, 411 first part, 412 second part, 500 air conditioning device, 501 outdoor unit, 502 indoor unit, 503 refrigerant piping, 504 compressor, 505 impeller, 510 outdoor fan, 511 yoke, 512 teeth, 514 split surface, 515 thin-walled connecting part (connecting part), 520 indoor fan, impeller 521.

Claims

1. An electric motor, wherein: The motor has: The annular stator core is formed by connecting a plurality of core parts via a connecting portion in a circumferential direction centered on the axis. a cover portion covering the stator core, the cover portion including a core surrounding portion surrounding the stator core from the outer side in a radial direction centered on the axis and a core adjacent portion protruding from the stator core in the direction of the axis; as well as The rotor comprises: a rotor core disposed on the inner side of the stator core in the radial direction; and a magnet mounted on the rotor core, wherein the magnet constitutes a first magnetic pole and a part of the rotor core constitutes a second magnetic pole. The shortest distance R1 in the radial direction from the axis to the outer periphery of the core peripheral portion and the shortest distance R2 in the radial direction from the axis to the outer periphery of the stator core satisfy R1 ≥ 1.15 × R2, The core surrounding portion and the core adjacent portion are made of materials having different mechanical properties, the core surrounding portion is stronger than the core adjacent portion, and the minimum radial thickness T1 of the core surrounding portion is thicker than the minimum radial thickness T2 of the core adjacent portion.

2. The electric motor according to claim 1, wherein: The shortest distance R1 and the shortest distance R2 satisfy R1≥1.20×R2.

3. The electric motor according to claim 1 or 2, wherein: The core peripheral portion includes a first portion located outside the connection portion of the stator core in the radial direction and a second portion adjacent to the first portion in the circumferential direction.

4. The electric motor according to claim 3, wherein: The maximum radial thickness A1 of the first portion, the shortest distance R1, and the shortest distance R2 satisfy R2+A1>R1.

5. The electric motor according to claim 3, wherein: The maximum radial thickness A1 of the first portion and the maximum radial thickness A2 of the second portion satisfy A1>A2.

6. The electric motor according to claim 3, wherein: The maximum thickness A2 of the second portion in the radial direction is the thinnest among the thicknesses in the radial direction of the core peripheral portion.

7. The electric motor according to claim 3, wherein: The first portion includes mounting legs formed on an outer periphery of the cover portion.

8. The electric motor according to claim 1 or 2, wherein: The materials having different mechanical properties all contain resin.

9. The electric motor according to claim 1 or 2, wherein: At least one of the materials having different mechanical properties contains a thermosetting resin.

10. The electric motor according to claim 1 or 2, wherein: At least one of the materials having different mechanical properties contains a thermoplastic resin.

11. A blower, wherein: The blower has: The electric motor according to any one of claims 1 to 10; and The impeller is driven to rotate by the motor.

12. An air conditioning device, wherein: The air conditioning apparatus includes an outdoor unit and an indoor unit connected to the outdoor unit via a refrigerant pipe. At least one of the outdoor unit and the indoor unit includes the air blower according to claim 11.

13. A method for manufacturing an electric motor, wherein: The method for manufacturing the electric motor comprises: A step of forming an annular stator core by connecting a plurality of core parts by a connecting portion in a circumferential direction centered on the axis; forming a cover portion that covers the stator core and includes a core peripheral portion that covers the stator core from the outside in a radial direction centered on the axis and a core adjacent portion that protrudes from the stator core in the direction of the axis; as well as a step of inserting a rotor into the radially inner side of the stator core, the rotor comprising a rotor core and a magnet mounted on the rotor core, the magnet constituting a first magnetic pole, and a portion of the rotor core constituting a second magnetic pole, In the process of forming the cover portion, the core surrounding portion and the core adjacent portion are formed of materials with different mechanical properties, and the cover portion is formed in a manner such that the shortest radial distance R1 from the axis to the outer periphery of the core surrounding portion and the shortest radial distance R2 from the axis to the outer periphery of the stator core satisfy R1≥1.15×R2, the strength of the core surrounding portion is higher than the strength of the core adjacent portion, and the minimum radial thickness T1 of the core surrounding portion is thicker than the minimum radial thickness T2 of the core adjacent portion.

14. The method for manufacturing an electric motor according to claim 13, wherein: In the step of forming the cover portion, the stator core is placed in a mold, and resin is injected into the mold to mold the cover portion.

15. The method for manufacturing a motor according to claim 13, wherein: In the step of forming the cover portion, The stator core is disposed in a first mold, and resin is injected into the first mold to form the core adjacent portion. The stator core is disposed in a second mold, and resin is injected into the second mold to mold the core peripheral portion.

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