Method for manufacturing electric motor

Abstract

This method for manufacturing an electric motor involves performing: a first operation for winding a conductive wire from one end side (Y1) to the other end side (Y2) of a winding drum part (42) in the radial direction (Y) of a yoke part while leaving a gap (G) between adjacent windings (46) in a first layer (1L); and a second operation for, after the first operation, winding the conductive wire around the first layer (1L) so as to contact the winding (46) positioned on the other end side (Y2), thereby moving at least some of the windings (46) wound in the first operation toward the one end side (Y1) and filling the gap (G).

Description

Electric motor manufacturing method

[0001] The present invention relates to a method for manufacturing an electric motor.

[0002] A known electric motor includes a stator core and an insulator provided at an end of the stator core, and a winding portion having multiple layers formed by winding a conductor in a concentrated manner around the teeth of the stator core and the winding drum of the insulator. In this type of electric motor, miniaturization and high efficiency are achieved by increasing the space factor of the conductor in the winding portion.

[0003] International Publication No. 2015 / 063877 Japanese Patent Application Laid-Open No. 2020-127255 Japanese Patent Application Laid-Open No. 2018-85870

[0004] In the electric motor described in Patent Document 1, the surface of the winding drum of the insulator is formed flat along the radial direction of the stator core. The winding portion includes a first layer formed by winding a conductor along the surface of the winding drum from one end side (outer diameter side) to the other end side (inner diameter side) in the radial direction of the stator core, and a second layer stacked on top of the first layer and formed by winding a conductor from the other end side (inner diameter side) to one end side (outer diameter side) in the radial direction of the stator core.

[0005] In such an electric motor, if the winding pitch (the amount of movement per turn of the nozzle in the winding process using a winding machine) of the first layer of windings, which are wound side by side in the radial direction of the stator core, is reduced in order to increase the space factor of the winding, a portion of a later-wound winding may ride up on an earlier-wound winding when forming the first layer of the winding. In this case, the later-wound winding may not be aligned with the other end (inner diameter side) of the earlier-wound winding, but may intrude on one end (outer diameter side) of the earlier-wound winding, and the slippery surface of the insulating film of the conductor may cause the earlier-wound winding to be pushed out toward the other end (inner diameter side) of the stator core (hereinafter also referred to as "winding irregularity"). When winding irregularities occur, the conductor wire that constitutes the winding, which is pulled so as to be pushed out to the end on the inner diameter side, may break, or the cross-sectional area of ​​the pulled conductor wire may decrease, increasing electrical resistance and the amount of heat generated by the conductor wire. In other words, the reliability of the conductor wire wound in the first layer of the winding may decrease. Note that this phenomenon is not limited to when the first layer of the winding is wound from the outer diameter side to the inner diameter side in the radial direction of the stator core, but can also occur when the first layer of the winding is wound from the inner diameter side to the outer diameter side in the radial direction of the stator core.

[0006] Meanwhile, there is a structure in which a groove or the like is provided on the winding drum of the insulator to prevent slippage of the conductor wound in the first layer of the winding section (Patent Document 2, Patent Document 3). However, in this structure, the groove or the like that matches the outer diameter of the conductor is provided on the winding drum, which requires changing the insulator depending on the outer diameter of the conductor, resulting in a problem of increased manufacturing costs for the motor. Furthermore, if a conductor with an outer diameter that does not match the size of the groove or the like is wound on the winding drum, a load may be applied to the conductor that has climbed onto the groove or the like, which may reduce the reliability of the current-carrying state of the conductor. In addition, as a result, a gap may be formed between the groove or the like and the conductor, which may actually reduce the space factor.

[0007] The disclosed technology has been made in consideration of the above, and aims to provide a method for manufacturing an electric motor that can increase the space factor of the winding portion while avoiding an increase in the manufacturing cost of the electric motor and improving the reliability of the wire wound in the first layer of the winding portion.

[0008] One aspect of the method for manufacturing an electric motor disclosed in the present application is a method for manufacturing an electric motor including a stator core having an annular yoke portion and teeth extending radially from the yoke portion, an insulator having a winding drum attached to the teeth portion, and a winding portion formed with multiple layers of windings in which a conductor wire is wound around the teeth portion via the winding drum, the method comprising: a first operation in which the conductor wire is wound from one end side to the other end side of the winding drum in the radial direction while leaving a gap between adjacent windings in the first layer of the winding portion; and a second operation in which, after the first operation, the conductor wire is wound in the first layer so as to be in contact with the winding located at the other end side, thereby moving at least a portion of the winding wound in the first operation toward the one end side and closing the gap.

[0009] According to one aspect of the method for manufacturing an electric motor disclosed in the present application, it is possible to avoid an increase in the manufacturing cost of the electric motor, improve the reliability of the conductor wound in the first layer of the winding portion, and increase the space factor of the winding portion.

[0010] FIG. 1 is a longitudinal cross-sectional view showing a compressor manufactured by a manufacturing method for an electric motor according to an embodiment. FIG. 2 is a bottom view showing a stator core according to the embodiment. FIG. 3 is a perspective view schematically showing an insulator according to the embodiment. FIG. 4 is a bottom view showing a stator according to the embodiment. FIG. 5 is a cross-sectional view schematically showing a winding section of an electric motor according to an embodiment. FIG. 6 is a cross-sectional view schematically showing a winding section of an electric motor according to a comparative example. FIG. 7 is a cross-sectional view illustrating a case where the first layer of winding is normally wound in the winding process of the comparative example. FIG. 8 is a cross-sectional view illustrating a case where the winding position of the first layer of winding is shifted in the winding process of the comparative example. FIG. 9 is a side view illustrating a case where the winding position of the first layer of winding is shifted in the winding process of the comparative example. FIG. 10 is a flowchart illustrating a winding process in the manufacturing method for an electric motor according to an embodiment. FIG. 11 is a flowchart illustrating the winding pitch in the winding process in the manufacturing method for an electric motor according to an embodiment. FIG. 12 is a cross-sectional view illustrating a first operation and a second operation performed in the winding process of the embodiment. Fig. 13 is a cross-sectional view for explaining a case where the first layer of winding is normally wound in the first operation of the winding process of the embodiment. Fig. 14 is a cross-sectional view for explaining a case where the winding position of the first layer of winding is shifted in the first operation of the winding process of the embodiment. Fig. 15 is a cross-sectional view for explaining a second operation in the embodiment. Fig. 16 is a cross-sectional view for explaining the first operation and the second operation performed in the winding process of the modified example.

[0011] Hereinafter, examples of the method for manufacturing an electric motor disclosed in the present application will be described in detail with reference to the drawings. Note that the method for manufacturing an electric motor disclosed in the present application is not limited to the following examples.

[0012] (Compressor) FIG. 1 is a longitudinal cross-sectional view showing a compressor including an electric motor manufactured by the electric motor manufacturing method of the embodiment. As shown in FIG. 1, compressor 1 is a so-called rotary compressor and includes a container 2, a shaft 3, a compression unit 5, and an electric motor 6. The container 2 is made of a metal material and defines a sealed internal space 7. The internal space 7 is generally cylindrical. When placed upright on a horizontal surface, the container 2 is shaped so that the central axis of the internal space 7 is parallel to the vertical direction. The container 2 defines an oil reservoir 8 below the internal space 7. The oil reservoir 8 stores lubricating oil for lubricating the compression unit 5. The container 2 is connected to a suction pipe 11 for drawing in refrigerant and a discharge pipe 12 for discharging compressed refrigerant. A shaft 3 is provided vertically and is disposed in the internal space 7 of the container 2 with one end immersed in the oil reservoir 8. The shaft 3 is supported by the container 2 so as to be rotatable about the central axis of the internal space 7. As the shaft 3 rotates, it supplies lubricating oil stored in an oil reservoir 8 to the compression section 5 .

[0013] The compression section 5 is disposed at the bottom of the internal space 7 and above the oil sump 8. The compressor 1 further includes an upper muffler cover 14 and a lower muffler cover 15. The upper muffler cover 14 is disposed above the compression section 5 in the internal space 7. The upper muffler cover 14 defines an upper muffler chamber 16 therein. The lower muffler cover 15 is disposed below the compression section 5 in the internal space 7 and above the oil sump 8. A lower muffler chamber 17 is defined within the lower muffler cover 15. The lower muffler chamber 17 is in communication with the upper muffler chamber 16 via a communication passage (not shown) formed in the compression section 5. A discharge hole 18 for discharging compressed refrigerant is defined between the upper muffler cover 14 and the shaft 3, and the upper muffler chamber 16 is in communication with the internal space 7 via the discharge hole 18.

[0014] The compression section 5 compresses the refrigerant supplied from the suction pipe 11 as the shaft 3 driven by the electric motor 6 rotates, and supplies the compressed refrigerant to the upper muffler chamber 16 and the lower muffler chamber 17. The refrigerant is compatible with the lubricating oil.

[0015] (Electric Motor) The electric motor 6 is disposed above the compression section 5 in the internal space 7. The electric motor 6 is a three-phase electric motor and includes a rotor 21 and a stator 22. The rotor 21 is fixed to the shaft 3. The stator 22 is formed in a generally cylindrical shape and is disposed on the outer periphery of the rotor 21 so as to surround the rotor 21, and is fixed to the container 2. The stator 22 includes a stator core 23, a lower insulator 25B as a first insulator, an upper insulator 25A as a second insulator, and a plurality of windings 46.

[0016] The upper insulator 25A is attached to the upper end of the stator core 23 in the axial direction of the shaft 3. The lower insulator 25B is attached to the lower end of the stator core 23 in the axial direction of the shaft 3. The upper insulator 25A and the lower insulator 25B are an example of an insulating portion that insulates the stator core 23 from the windings 46. In this embodiment, the upper insulator 25A and the lower insulator 25B are formed in the same shape and are used as the upper insulator 25A when provided at the upper end of the stator core 23, and as the lower insulator 25B when provided at the lower end of the stator core 23. Hereinafter, in this embodiment, the upper insulator 25A and the lower insulator 25B will be collectively referred to as the insulator 25. Note that the upper insulator 25A and the lower insulator 25B may be formed in different shapes.

[0017] FIG. 2 is a bottom view showing the stator core 23 according to the embodiment. As shown in FIG. 2, the stator core 23 is formed by stacking multiple metal plates made of a soft magnetic material, such as electromagnetic steel plates, and includes a yoke portion 31 and multiple stator core teeth portions 32 (32-1 to 32-9). The yoke portion 31 is formed in a generally annular (cylindrical) shape. Of the multiple stator core teeth portions 32-1 to 32-9, the first stator core teeth portion 32-1 is formed in a generally columnar shape extending in the radial direction of the stator core 23. One end of the first stator core teeth portion 32-1 is connected to the inner circumferential surface of the yoke portion 31, i.e., it extends from the inner circumferential surface of the yoke portion 31 inward in the radial direction of the yoke portion 31. Of the multiple stator core teeth portions 32-1 to 32-9, stator core teeth portions 32-2 to 32-9 that are different from first stator core teeth portion 32-1 are also formed in a generally cylindrical shape, similar to first stator core teeth portion 32-1, and extend radially inward from the inner circumferential surface of yoke portion 31. In the case of stator 22 with nine slots, the multiple stator core teeth portions 32-1 to 32-9 are formed on the inner circumferential surface of yoke portion 31 so as to be equally spaced at 40° intervals in the circumferential direction of yoke portion 31.

[0018] FIG. 3 is a perspective view schematically illustrating an insulator 25 according to an embodiment. As shown in FIG. 3, the insulator 25 (upper insulator 25A and lower insulator 25B) is formed into a ring shape from an insulating material, such as polybutylene terephthalate (PBT) resin. As shown in FIG. 3, the insulator 25 includes an outer peripheral wall 41, a plurality of insulator teeth 42 (42-1 to 42-9) that serve as a winding body around which a conductor (winding 46) is wound, and a plurality of flanges 43 (43-1 to 43-9). The outer peripheral wall 41 is formed in a generally cylindrical shape. A plurality of slits 44 are formed in the outer peripheral wall 41 at intervals around the circumferential direction of the outer peripheral wall 41, extending from one end of the outer peripheral wall 41 in a direction along the central axis of the outer peripheral wall 41 (the axial direction of the shaft 3) along the central axis of the outer peripheral wall 41. The other end of the outer peripheral wall 41 in the direction along the central axis of the outer peripheral wall 41 contacts the stator core 23. In other words, the multiple slits 44 are formed to extend from one end of the outer peripheral wall 41 opposite the stator core 23 toward the stator core 23. When a winding 46 (conductor) drawn from a winding portion 45 (described later) is passed through each slit 44, the winding 46 drawn from the inner peripheral side to the outer peripheral side of the outer peripheral wall 41 forms a crossover wire 49 that is suspended along the outer peripheral surface of the outer peripheral wall 41. Note that the insulator 25 shown in FIG. 3 schematically illustrates the shape and arrangement of each slit 44 in the outer peripheral wall 41, and the shape and arrangement of each slit 44 will be described in detail later.

[0019] Of the multiple insulator teeth 42-1 to 42-9, the first insulator tooth 42-1 is formed in the shape of a right column with a roughly semicircular cross section. One end of the first insulator tooth 42-1 is formed to be connected to the inner circumferential surface of the outer peripheral wall 41, that is, it extends from the inner circumferential surface of the outer peripheral wall 41 to the radially inward direction of the outer peripheral wall 41. Of the multiple insulator teeth 42-1 to 42-9, the insulator teeth 42-2 to 42-9 that are different from the first insulator tooth 42-1 are also formed in the shape of a right column with a roughly semicircular cross section, like the first insulator tooth 42-1, and extend from the inner circumferential surface of the outer peripheral wall 41 to the radially inward direction of the outer peripheral wall 41. The multiple insulator teeth 42-1 to 42-9 are formed on the inner peripheral surface of the outer peripheral wall 41 and are arranged at equal intervals of 40 degrees in the circumferential direction of the outer peripheral wall 41. Note that the insulator teeth 42 in the embodiment are not limited to a shape of a rectangular column having a substantially semicircular cross section, and may be formed, for example, in a shape of a rectangular column having a substantially polygonal cross section.

[0020] The plurality of flanges 43-1 to 43-9 correspond to the plurality of insulator teeth 42-1 to 42-9 and are each formed in a generally semicircular plate shape. Of the plurality of flanges 43-1 to 43-9, the first flange 43-1 corresponding to the first insulator tooth 42-1 is continuous with the other end of the first insulator tooth 42-1 and is formed integrally with the first insulator tooth 42-1. Similarly to the first flange 43-1, the other flanges 43 of the plurality of flanges 43-1 to 43-9 that are different from the first flange 43-1 are also continuous with the other ends of the plurality of insulator teeth 42-1 to 42-9 and are formed integrally with the respective insulator teeth 42-1 to 42-9.

[0021] FIG. 4 is a bottom view showing the stator 22 in the embodiment, as viewed from the side of the lower insulator 25B. As shown in FIG. 4, a plurality of windings 46 (U-phase windings 46-U1 to 46-U3, V-phase windings 46-V1 to 46-V3, and W-phase windings 46-W1 to 46-W3, which will be described later) are wound around each of the plurality of stator core teeth 32-1 to 32-9 of the stator core 23. As shown in FIG. 4, a winding section (coil) 45 is formed on each of the stator core teeth 32-1 to 32-9 by the windings 46 (conductor wires) of each phase. Each winding section 45 has a plurality of layers, for example, six to eight layers, of windings 46, in which conductor wires are wound around the stator core teeth 32 via the insulator teeth 42. The nine slot-forming winding portions 45 are numbered 1 to 9 in clockwise order in Fig. 4. The nine winding portions 45 are arranged along the circumferential direction of the stator core 23 so that the three phases repeat the same order. That is, they are arranged so that the U phase, V phase, and W phase repeat in clockwise order in Fig. 4.

[0022] The electric motor 6 in this embodiment is a 6-pole, 9-slot concentrated winding type electric motor. The windings (conductors) 46 include a plurality of U-phase windings 46-U1 to 46-U3 that form the U-phase winding portion 45, a plurality of V-phase windings 46-V1 to 46-V3 that form the V-phase winding portion 45, and a plurality of W-phase windings 46-W1 to 46-W3 that form the W-phase winding portion 45.

[0023] Although the electric motor 6 of the embodiment is configured with nine slots, the number of slots, i.e., the number of winding portions 45 (or the number of stator core teeth portions 32) is not limited thereto.

[0024] Furthermore, although the stator core 23 in the embodiment has an annular yoke portion 31 that is integrally formed, the yoke portion may be formed by connecting and assembling a plurality of arc-shaped yoke components (not shown) into an annular shape. Furthermore, although the stator core teeth 32 of the stator core 23 in the embodiment extend from the inner peripheral surface of the yoke portion 31 radially inward of the yoke portion 31, they may extend from the outer peripheral surface of the yoke portion 31 radially outward of the yoke portion 31. Similarly, the insulator teeth 42 of the insulator 25 are not limited to a shape that extends from the inner peripheral surface of the outer peripheral wall portion 41 radially inward of the outer peripheral wall portion 41, but may extend from the outer peripheral surface of the outer peripheral wall portion 41 radially outward of the outer peripheral wall portion 41.

[0025] (Winding Section of Electric Motor) Figure 5 is a cross-sectional view that schematically shows the winding section (coil) 45 of the electric motor 6 of the embodiment. In Figure 5, the windings of the first layer 1L of the winding section 45 are indicated by the letters "F" and "S" to distinguish between the windings, with the windings 46 wound in a first operation (described below) being indicated by the letter "F" and the windings 46 wound in a second operation (described below) being indicated by the letter "S." Also, in Figure 5, the numbers "2 to 8" that are indicated on the windings 46 of each layer of the winding section 45 indicate the second layer 2L to the eighth layer 8L.

[0026] 5 , the conductor wire supplied from the nozzle N is wound around the winding portion 45 in this embodiment at a predetermined winding pitch (the amount of movement of the nozzle N in the radial direction Y per turn) so as to be aligned in the radial direction Y of the yoke portion 31 (which also corresponds to the radial direction Y of the outer peripheral wall portion 41; hereinafter simply referred to as the radial direction Y). The winding 46 wound as the first layer 1L of the winding portion 45 is wound in the radial direction Y in contact with the first layer 1L of the winding portion 45, i.e., the surface of the insulator teeth 42 on which the conductor wire is wound (hereinafter referred to as the surface of the insulator teeth 42). The winding portion 45 in this embodiment has an increased space factor without causing any irregular winding of the winding 46 of the first layer 1L, which will be described in detail later.

[0027] The winding pitch here refers to the amount of movement of the nozzle N in the radial direction Y per turn of the conductor (winding 46) wound in the radial direction Y around the insulator teeth 42 and the stator core teeth 32, and is different from the pitch dimension between adjacent windings 46 in the radial direction Y. For convenience, the winding pitch is also shown as a pitch dimension in the drawings, but in the following description, the winding pitch refers to the amount of movement of the nozzle N in the radial direction Y per turn. Note that the amount of movement of the nozzle N refers to the amount of change in the relative position between the nozzle N and the insulator teeth 42. In other words, when changing the relative position of the nozzle N with respect to the insulator teeth 42, the insulator teeth 42 side may be fixed and the nozzle N side may move, the nozzle N side may be fixed and the insulator teeth 42 side may move, or both the insulator teeth 42 side and the nozzle N side may move.

[0028] (Method of Manufacturing Electric Motor) The method of manufacturing an electric motor according to the embodiment includes a winding step in which a conductor wire is wound around the stator core teeth 32 via the insulator teeth 42 to form a winding portion (coil) 45. As shown in Fig. 5 , in the winding step of the embodiment, the conductor wire is wound using a winding machine (not shown) having a nozzle N that supplies the conductor wire. Features of the method of manufacturing an electric motor according to the embodiment include that in the winding step, the operation of winding the conductor wire into the first layer 1L of the winding portion 45 and the amount of movement (winding pitch) of the nozzle N that supplies the conductor wire to be wound into the first layer 1L are controlled by a controller C of the winding machine.

[0029] In the winding process, the winding 46 is supplied from a nozzle N that moves in the radial direction Y of the stator core 23, and is wound around the stator core teeth portions 32 of the stator core 23 and the insulator teeth portions 42 of the insulator 25 that are attached to and overlap the stator core teeth portions 32, and the crossover wire 49 drawn out from the winding portion 45 is wound around the outer peripheral wall portion 41 of the insulator 25. In the embodiment, when forming each of the three-phase winding portions 45 using a winding machine, for example, a so-called three-nozzle winding method is applied, in which the winding portion 45 is formed for each phase using three nozzles N, and the winding portions 45 for each phase are formed in order to form the three-phase winding portions 45.

[0030] (Winding Process of Comparative Example) First, the winding process of the electric motor manufacturing method of the comparative example will be described for comparison with the winding process of the electric motor manufacturing method of the embodiment. In the winding process of the comparison, in order to increase the space factor of the winding portion, the conductor is wound so that P<B (e.g., P=0.8B) is satisfied, where B is the outer diameter of the conductor before winding and P is the winding pitch of the first layer 1L of the winding portion (the amount of movement of the nozzle N in the radial direction Y per turn). Note that the outer diameter B of the conductor tends to be slightly smaller when the conductor is wound around the winding portion because the conductor stretches in the longitudinal direction due to tension applied when the conductor is wound around the stator core teeth 32 via the insulator teeth 42.

[0031] FIG. 6 is a cross-sectional view schematically illustrating the winding section 145 of the electric motor of the comparative example when the first layer 1L of the winding is wound normally. In FIG. 6, the numbers "1 to 8" attached to the windings 46 of each layer of the winding section 145 indicate the first layer 1L to the eighth layer 8L. As shown in FIG. 6, the winding section 145 of the comparative example has, for example, eight layers of windings 46, and the conductor is wound so that the winding pitch P of all layers from the first layer 1L to the eighth layer 8L satisfies P<B. Therefore, the first layer 1L to the eighth layer 8L of the winding section 145 are wound so that adjacent windings 46 in the radial direction Y are in close contact with each other.

[0032] (Winding Process of Comparative Example) Figure 7 is a cross-sectional view illustrating a case where the winding of the first layer 1L is normally wound in the winding process of the comparative example. As shown in Figure 7, in the comparative example, in the first layer 1L, the second-turn 2T winding 46 slides down the outer peripheral surface of the first-turn 1T winding 46 to the other end side Y2 in the radial direction Y (the inner diameter side, which is inward in the radial direction Y). As a result, the conductor is wound so that the second-turn 2T winding 46 and the third-turn 3T winding 46 are adjacent to and in contact with each other in order, following the first-turn 1T winding 46. From the fourth turn 4T onwards, the winding pitch P satisfies P < B, so that the conductor is wound in an aligned state so that adjacent windings 46 are in contact with each other in the radial direction Y. In other words, when the windings 46 (conductors) forming the first layer 1L are normally wound, the windings 46 of the first layer 1L are densely wound with no gaps between them.

[0033] Fig. 8 is a cross-sectional view illustrating a case where the winding position of the winding 46 of the first layer 1L is shifted during the winding process of the comparative example. Fig. 9 is a side view illustrating a case where the winding position of the winding 46 is shifted during the winding process of the comparative example.

[0034] As shown in FIG. 8 , in the winding process of the comparative example, in the first layer 1L wound on the insulator tooth portion 42, for example, the second turn 2T winding 46 wound following the first turn 1T winding 46 may slide toward the other end Y2 in the radial direction Y (the inner diameter side, which is inside in the radial direction Y) from the position adjacent to and in contact with the first turn 1T winding 46, and the winding position of the second turn 2T winding 46 may become significantly separated from the first turn 1T winding 46.

[0035] At this time, in the comparative example, because the winding pitch (the amount of movement of the nozzle N in the radial direction Y per turn) P is P<B (P=0.8B), the third turn 3T winding 46 is advanced by 0.8B from the winding position where the second turn 2T winding 46 would normally be wound. As a result, the third turn 3T winding 46 cannot get over the second turn 2T winding 46 toward the other end Y2 in the radial direction Y (the inner diameter side, which is the inside in the radial direction Y), and is wound closer to the first turn 1T winding 46 side (the outer diameter side, which is one end Y1 in the radial direction Y) than the position of the second turn 2T winding 46. As a result, the third turn 3T winding 46 gets caught between the first turn 1T winding 46 and the second turn 2T winding 46, causing a part of the third turn 3T winding 46 to ride up onto the second turn 2T winding 46 and get wound around, causing winding irregularities.

[0036] Next, the fourth turn 4T winding 46 is advanced by 0.8 B, which is smaller than the outer diameter B of the conductor before winding, from the winding position of the second turn 2T winding 46, which is located at the winding position where the third turn 3T winding 46 would normally be wound. As a result, the fourth turn 4T winding 46 is wound adjacent to the second turn 2T winding 46 on the opposite side in the radial direction Y from the third turn 3T winding 46 side (one end Y1 in the radial direction Y).

[0037] 9 , for example, if the third turn 3T and fourth turn 4T windings 46 are sandwiched between the first turn 1T winding 46 and the second turn 2T winding 46, the second turn 2T winding 46 continues to shift in the radial direction Y away from the first turn 1T winding 46 (toward the other end Y2, which is the direction toward the flange 43), causing winding irregularities and pulling the second turn 2T winding 46 in particular toward the other end Y2 in the radial direction Y (the inner diameter side, which is the inside of the radial direction Y), reducing the cross-sectional area, increasing the electrical resistance, and increasing the heat generation of the winding 46. Furthermore, if winding irregularities occur in the first layer 1L, the conductor wound in the second layer 2L will ride up on the winding 46 with the irregular winding, causing the winding portion 45 to bulge significantly in the lamination direction (the winding radial direction, for example, the axial direction of the shaft 3), resulting in a problem of distortion and enlargement of the winding portion 45.

[0038] As described above, if the winding pitch P of the wire 46 (conductor) wound on the first layer 1L is set to satisfy P<B in order to increase the space factor of the winding portion 145, there is a problem that winding irregularities are likely to occur in the wire 46 wound on the first layer 1L. Note that, as an example, a case has been shown here in which winding irregularities begin when the second turn 2T of the wire 46 on the first layer 1L slips on the insulator teeth 42, but similar winding irregularities may occur at any position in the radial direction Y in the first layer 1L where the wire 46 is wound in contact with the surface of the insulator teeth 42.

[0039] (Winding Process of the Example) In the winding process of the method for manufacturing the electric motor of the example, when continuously winding one conductor wire to form the first layer 1L, a first operation of winding the conductor wire and a second operation of winding the conductor wire after the first operation are performed. Fig. 10 is a flowchart for explaining the winding process in the method for manufacturing the electric motor of the example.

[0040] 10 , in a first operation, the conductor is wound from the outer peripheral wall 41 side, which is one end side Y1 in the radial direction Y of the insulator teeth 42, toward the flange 43 side, which is the other end side Y2 in the radial direction Y, while leaving a gap G between adjacent windings 46 in the first layer 1L of the winding portion 45 (step S1). In a second operation, after the first operation, the next conductor is wound onto the first layer 1L so as to be in contact with the winding 46 located on the flange 43 side (the other end side Y2 in the radial direction Y) wound in the first operation, thereby moving at least a portion of the winding 46 wound in the first operation toward the outer peripheral wall 41 side (the one end side Y1 in the radial direction Y) and closing the gap G (step S2).

[0041] In the second operation, it is preferable that the conductor be wound so as to contact the winding 46 (hereinafter also referred to as the "other-end winding 46") located on the other end side Y2 (inner diameter side) in the radial direction Y of the insulator tooth portion 42, among the windings 46 wound in the first operation, because this closes the gap G from the other end side Y2 (inner diameter side) in the radial direction Y. This is not limited to this, and in the second operation, the conductor may be wound so as to enter and contact the winding 46 at the other end and the adjacent winding 46 on the outer peripheral wall portion 41 side of the other end winding 46, thereby pushing the adjacent winding 46 toward the outer peripheral wall portion 41 (one end side Y1). Furthermore, it is preferable that the conductor be wound so as to contact the outer peripheral surface of the other end winding 46 on the flange portion 43 side (the other end side Y2 in the radial direction Y) of the outer peripheral surface of the other end winding 46. 15 , which will be described later, the winding 46(S) wound in the second operation comes into contact with the outer peripheral surface of the other end winding 46(F) wound in the first operation, on the flange 43 side, whereby a force f1 directed toward one end side Y1 (outer diameter side) in the radial direction Y and a force f2 directed toward the stator core 23 in the central axis direction of the outer peripheral wall 41 are applied to the other end winding 46(S) wound in the first operation. Then, the force f1 directed toward the one end side Y1 (outer diameter side) in the radial direction Y, which is received from the winding 46(S) wound in the second operation, can push the other end winding 46(F) wound in the first operation toward the outer peripheral wall 41 side (the outer diameter side, which is the one end side Y1 in the radial direction Y).

[0042] In the second operation, if the conductor is wound so as to contact the outer peripheral surface of the other-end winding 46(F) on the outer peripheral wall 41 side (one end side Y1 in the radial direction Y), the winding 46(S) wound in the second operation will enter between the other-end winding 46(F) wound in the first operation and the adjacent winding 46(F) on the outer peripheral wall 41 side (one end side Y1 in the radial direction Y) of the other-end winding 46, and will push the adjacent winding 46(F) toward the outer peripheral wall 41 side (one end side Y1 in the radial direction Y). In this case, a part of the winding 46(S) wound in the second operation will ride up on the other-end winding 46(F) wound in the first operation, causing slight winding irregularities on the other end side Y2 in the radial direction Y of the first layer 1L. However, such winding irregularities only occur on the other end side Y2 in the radial direction Y of the first layer 1L after the winding of the winding 46 in the first layer 1L is almost complete, and are tolerable because they have little effect on the winding state of the winding portion 45 or the reliability of the wire.

[0043] Furthermore, in the second operation, the conductor wire is not limited to being wound one turn (one revolution), but may be wound multiple times, for example, two to four turns, depending on the size of the gap G between the windings 46 (F) wound in the first operation. Increasing the number of turns in this way enhances the effect of reducing the gap G, and also increases the number of windings 46 (F, S) wound in the first layer 1L, thereby improving the space factor.

[0044] In the winding process of the embodiment, the first operation is an operation to prevent winding irregularities that tend to occur in the windings 46 of the first layer 1L. The second operation is an operation to close the gaps G between the windings 46 (F) wound in one operation. The second operation may be an operation to reduce (narrow) at least one gap G among the gaps G at multiple locations. The second operation increases the number of turns of the windings 46 in the first layer 1L, thereby improving the alignment of the windings 46 of the second layer 2L and subsequent layers that are layered on the first layer 1L where the gaps G between the windings 46 have been reduced.

[0045] (Winding Pitch) Fig. 11 is a flowchart illustrating the winding pitch in the winding process in the manufacturing method of the electric motor of the embodiment. Fig. 12 is a cross-sectional view illustrating the first and second operations performed in the winding process of the embodiment. The following description will be made with reference to Figs. 11, 12, and 5. In Fig. 12, as in Fig. 5, in the first layer 1L of the winding section 45, the windings 46 wound in the first operation are indicated by an "F" and the windings 46 wound in the second operation are indicated by an "S."

[0046] While the winding pitch P (the amount of movement of the nozzle N in the radial direction Y per turn) in the comparative example described above is P<B (P=0.8B), in the first operation of the winding process in the example, as shown in FIGS. 5 and 11 , the conductor is wound in the first layer 1L of the winding section 45 so that the first pitch P1 satisfies P1>B, where P1 is the winding pitch at which the conductor is wound in the first operation and B is the outer diameter of the conductor before winding (step S3). This allows the winding 46(F) to be wound without winding irregularities in the first layer 1L (see FIG. 14 ). When winding the conductor in the first layer 1L in the first operation, the nozzle N moves along the radial direction Y from the outer peripheral wall portion 41 side, which is one end side Y1 of the insulator teeth 42 in the radial direction Y, toward the flange portion 43 side, which is the other end side Y2 in the radial direction Y. The first pitch P1, which is the amount of movement of the nozzle N, is controlled by a control unit C of the winding machine.

[0047] When the second pitch, which is the winding pitch for winding the conductor in the second operation after the first operation, is P2, in the second operation, the conductor is wound on the first layer 1L of the winding unit 45 so that the second pitch P2 satisfies P2 < P1 (step S4). This allows the winding 46(S) wound in the second operation to close the gap G between the windings 46(F) wound in the first operation (see FIG. 15). In the second operation, the second pitch P2, which is the amount of movement of the nozzle N, is also controlled by the control unit C of the winding machine.

[0048] When the third pitch, which is the winding pitch of the conductor wire wound in the second layer 2L and subsequent layers of the winding unit 45, is P3, after the second operation in which the winding of the winding wire 46 in the first layer 1L is completed, the conductor wire is wound in the second layer 2L and subsequent layers so that the third pitch P3 satisfies P3 < P1 (step S5). This increases the number of turns in each layer from the second layer 2L onwards, thereby increasing the space factor of the winding unit 45. The third pitch P3, which is the amount of movement of the nozzle N, is also controlled by the control unit C of the winding machine. In this embodiment, the third pitch P3 is set to a value that satisfies P2 < P3 < P1.

[0049] As described above, the nozzle N winds the conductor wire while reciprocating in the radial direction Y. That is, the nozzle N winds the conductor wire in the first layer 1L by a first operation and a second operation on the outward path of the reciprocating movement, winds the conductor wire in the second layer 2L on the return path of the reciprocating movement, and winds the conductor wire from the third layer 3L onward by repeating the reciprocating movement a predetermined number of times. Furthermore, in the winding process of the embodiment, the stator core 23 and the insulator 25 are rotated in the radial direction Y in accordance with the movement of the nozzle N, so that the conductor wire is wound around the stator core teeth 32 via the insulator teeth 42. In addition, the direction in which the winding 46 (conductor) is wound in the radial direction Y in the first layer 1L, i.e., the movement direction of the nozzle N in the first layer 1L, is not limited to the direction from the outer wall portion 41 side toward the flange portion 43 side (the direction from one end side Y1 (outside) in the radial direction Y toward the other end side Y2 (inside)), but may also be the direction from the flange portion 43 side toward the outer wall portion 41 side (the direction from the other end side Y2 (inside) in the radial direction Y toward one end side Y1 (outside)).

[0050] In the first operation, it is preferable to wind the conductor wire so that the first pitch P1 satisfies P1<2B. If the first pitch P1 is 2B or more, the gap G between adjacent windings 46 becomes large, and there is a risk that the gap G will not be properly closed by the second operation. Furthermore, if the first pitch P1 is 2B or more, the number of turns in the first layer 1L decreases, making it easier for the windings 46 of the second layer 2L to enter the gap G between the windings 46 in the first layer 1L, which may reduce the alignment of the winding portion 45. These problems can be avoided by making the first pitch P1 satisfy P1<2B.

[0051] In the second operation, multiple turns of the conductor are wound. In the embodiment, as an example, the winding 46 (conductor) is wound two turns in the second operation, but the number of turns of the winding 46 in the second operation is not limited. The number of turns of the winding 46 in the second operation is set to, for example, approximately one to four turns. In the second operation, the second turn of the winding 46 (S) is wound by advancing the second pitch P2 relative to the first turn of the winding 46 (S), but the second pitch P2 may be different for each turn. In the second operation, the conductor may be wound so that the second pitch P2 gradually decreases, for example, from the first turn to the last turn.

[0052] In the second operation, the conductor is wound so that the second pitch P2 satisfies 0≦P2<(B / 2), thereby appropriately narrowing the gap G between the windings 46 wound in the first operation.

[0053] When the second pitch P2 satisfies P2 = 0, the conductor wire is wound at the same position on the insulator tooth portion 42 in the radial direction Y. In other words, when the second pitch P2 satisfies P2 = 0, the conductor wire wound in the second operation is wound around the winding 46 (F) located at the other end (on the flange 43 side) wound in the first operation while contacting either the flange 43 side (the other end side Y2 in the radial direction Y) or the outer circumferential wall portion 41 side (one end side Y1 in the radial direction Y) of the outer circumferential surface of the other end winding 46.

[0054] In this case, from the viewpoint of moving the other-end winding 46 toward the outer peripheral wall 41 by the conductor wound in the second operation to close the gap G, it is desirable for the conductor wound in the second operation to contact the flange 43 side of the outer peripheral surface of the other-end winding 46, but it may also contact the outer peripheral wall 41 side of the outer peripheral surface of the other-end winding 46. When the conductor wound in the second operation is wound in contact with the outer peripheral wall 41 side of the outer peripheral surface of the other-end winding 46, it enters between the other-end winding 46 and the adjacent winding 46, pushing the adjacent winding 46 toward the outer peripheral wall 41 side (one end side Y1 in the radial direction Y) and closing the gap G. At this time, a portion of the winding 46 wound in the second operation rides up on the other-end winding 46, causing slight winding irregularities at the other end side Y2 in the radial direction Y of the first layer 1L. However, such irregular winding occurs only at the other end Y2 in the radial direction Y of the first layer 1L after the winding of the winding 46 in the first layer 1L is almost complete, and is tolerable because it has little effect on the winding state of the winding portion 45 or the reliability of the conductor. If the second pitch P2 is (B / 2) or greater, the conductor wound in the second operation will be wound away from the winding 46 at the other end (on the flange 43 side) wound in the first operation without coming into contact with it, and there is a risk that the gap G will not be closed.

[0055] 13 is a cross-sectional view illustrating a case where the winding wire 46 of the first layer 1L is normally wound in the first operation of the winding process of the embodiment. As shown in FIG. 13 , in the first operation of the winding process of the embodiment, in the first layer 1L, the conductor is wound in order from the first turn 1T of the winding wire 46 to the second turn 2T of the winding wire 46 and the third turn 3T of the winding wire 46 so that a gap G is left between them. By winding the conductor from the fourth turn 4T onwards so that the first pitch P1 satisfies P1 > B, the winding wires 46 are wound in alignment with a gap G left between adjacent turns in the radial direction Y.

[0056] 14 is a cross-sectional view illustrating a case where the winding position of the first layer 1L winding 46 is shifted in the first operation of the winding process of the embodiment. As shown in Fig. 14, in the first operation of the winding process of the embodiment, as in the winding process of the comparative example described above (see Fig. 8), for example, in the first layer 1L, the second turn 2T winding 46 wound following the first turn 1T winding 46 may slip in the radial direction Y on the insulator teeth 42 from the winding position where the second turn 2T winding 46 would normally be wound, and the winding position of the second turn 2T winding 46 may become separated from the first turn 1T winding 46.

[0057] Even in such a case, in the first operation of the winding process of this embodiment, the conductor wire is wound so that the first pitch P1 of the first layer 1L satisfies P1 > B, thereby ensuring an appropriate amount of movement of the nozzle N, and therefore the next third-turn 3T winding 46 can smoothly pass over the misaligned second-turn 2T winding 46. The third-turn 3T winding 46 is wound around the surface of the insulator teeth 42 while contacting the flange 43 side of the outer peripheral surface of the second-turn 2T winding 46. Therefore, the third-turn 3T winding 46 does not get caught between the first-turn 1T winding 46 and the second-turn 2T winding 46 as in the comparative example, but is appropriately wound on the opposite side of the second-turn 2T winding 46 from the first-turn 1T winding 46.

[0058] In other words, the first pitch P1 (the movement amount of the nozzle N) of the first layer 1L in the first operation is preferably set to a value obtained by adding a predetermined value corresponding to the maximum amount of misalignment of the winding position of the winding 46 expected in the first layer 1L, i.e., the maximum amount of slippage of the winding 46, to the outer diameter B of the conductor (the upper limit of the dimensional tolerance). Note that the first pitch P1 of the first layer 1L in the first operation may be set to a value equal to or greater than a value that allows the next winding 46 to be wound so as to come into contact with the outer peripheral surface of the misaligned winding 46 (the other end side Y2 of the outer peripheral surface that is closer to the flange 43). This allows the next winding 46 to pass over the misaligned winding 46 in the first operation of the winding process of this embodiment. Therefore, in the first operation of the winding process of the embodiment, the order of each turn of the winding 46 wound on the first layer 1L is not disturbed, and the order of each turn of the winding 46 is correctly wound, thereby preventing winding disturbances from occurring on the first layer 1L.

[0059] In the first operation, even if the winding position of the previously wound winding 46 after the fourth turn 4T is shifted, the next winding 46 is wound smoothly over the previously wound winding 46, so that winding irregularities in the first layer 1L can be prevented.

[0060] 15 is a cross-sectional view illustrating the second operation in the embodiment. In FIG. 15, in the first layer 1L of the winding section 45, the windings 46 wound in the first operation are indicated by an "F" and the windings 46 wound in the second operation are indicated by an "S."

[0061] 15 , in the second operation, the conductor wire is wound so that the second pitch P2 satisfies P2 < P1, whereby the conductor wire (S) is wound so as to be in contact with the winding 46(F) located at the other end in the radial direction Y, of the windings 46(F) wound in the first operation. When the conductor wire (S) is wound in the second operation, this conductor wire (S) is wound around the surface of the insulator teeth 42 while being in contact with the outer circumferential surface of the winding 46(F) at the other end in the radial direction Y, on the flange 43 side (the other end side Y2 in the radial direction Y), whereby a force f1 is applied from the winding 46(S) wound in the second operation to the winding 46(F) at the other end, wound in the first operation, in a direction toward one end side Y1 in the radial direction Y (outer diameter side). This force f1 toward the one end side Y1 (outer diameter side) in the radial direction Y pushes the winding 46(F) at the other end toward the one end side Y1 (outer diameter side) in the radial direction Y, moving it toward the outer circumferential wall portion 41 (one end side Y1 in the radial direction Y). As a result, the gap G between the winding 46(F) at the other end and the winding 46(F) adjacent to the winding 46(F) at the other end is closed, and the windings 46(F) at these two locations come into contact with each other.

[0062] Subsequently, in the second operation, the next conductor wire (S) is wound so that the second pitch P2 satisfies P2 < P1. This causes the conductor wire (S) to be wound around the surface of the insulator teeth 42 while contacting the outer peripheral surface on the flange 43 side (the other end side Y2 in the radial direction Y) of the winding 46 (S) previously wound in the second operation. This pushes the winding 46 (S) previously wound in the second operation and moves it toward the outer peripheral wall 41 side (one end side Y1 in the radial direction Y). This closes the gaps G between the windings 46 (F) located closer to the outer peripheral wall 41 than the winding 46 (S) previously wound in the second operation. The same applies when further conductor wires are wound in the second operation, and the gaps G between the windings 46 (F) wound on the outer peripheral wall 41 side are further closed.

[0063] In addition, when viewed in cross section along the radial direction Y, the surface of the insulator tooth 42 around which the conductor wire is wound has a flat surface 42a extending along the radial direction Y and an arc-shaped curved surface 42b that is inclined relative to the flat surface 42a. The flat surface 42a extends from the inner circumferential surface of the outer peripheral wall 41. The curved surface 42b extends from a side surface of the flange 43 that faces the outer peripheral wall 41, and is formed smoothly and continuously on the flange 43 side of the flat surface 42a (the other end side Y2 in the radial direction Y).

[0064] In the second operation, the winding 46 wound on the curved surface 42b of the insulator tooth 42 may slide along the curved surface 42b toward the flat surface 42a, thereby moving the winding 46 wound on the flange 43 side of the insulator tooth 42 in the radial direction Y (the other end side Y2 in the radial direction Y) toward the outer circumferential wall 41 side (the one end side Y1 in the radial direction Y). By utilizing the sliding force of the winding 46 wound on the curved surface 42b in this way, the gap G between the windings 46 (F) wound in the first operation can be smoothly closed.

[0065] The inclined surfaces formed on the insulator teeth 42 are not limited to curved surfaces (R-surfaces) 42b formed with a single curvature, but may be, for example, C-surfaces, surfaces formed by a series of C-surfaces with different inclination angles, or surfaces formed by a series of R-surfaces with different curvatures. To facilitate sliding of the winding 46 wound on the inclined surfaces, the flange 43 side of the insulator teeth 42 may be subjected to a surface treatment such as a coating that reduces the static friction coefficient.

[0066] The relational expression for the outer diameter B of the conductor used in the winding process of the embodiment preferably holds even when this outer diameter B is set to the upper limit of the dimensional tolerance of the outer diameter of the conductor (maximum finished outer diameter). This allows the winding pitch (first pitch P1, second pitch P2, etc.) to be optimally set, thereby most appropriately preventing irregular winding of the winding 46 wound in the first layer 1L by the first operation and reducing the gap G between the windings 46 by the second operation. As shown in FIG. 5 , the conductor (winding 46) here includes a conductor 46a and an insulating film 46b covering the conductor 46a, and the outer diameter B of the conductor includes the thickness of the insulating film 46b. For example, the outer diameter of the conductor 46a in the embodiment is 0.8 mm, and the upper limit of the dimensional tolerance of the outer diameter B of the conductor covered with the insulating film 46b is set to 0.88 mm.

[0067] Note that the crossover wire 49 drawn out from the winding portion 45 is less likely to stretch due to tension than the winding 46, and therefore has a larger outer diameter than the portion of the conductor forming the winding 46 and is closer to the outer diameter B of the conductor before being wound. Therefore, the outer diameter B of the conductor before being wound can be approximated to the outer diameter of the conductor as the crossover wire 49 extending from the winding portion 45 to the outer peripheral wall 41. Therefore, in this embodiment, the outer diameter of the conductor of the crossover wire 49 extending from the winding portion 45 to the outer peripheral wall 41 is treated as the outer diameter B of the conductor before being wound.

[0068] The insulating film 46b contains, for example, polyamideimide, and has a static friction coefficient of 0.12 or less. In the example, the insulating film 46b has high lubricity, with a static friction coefficient of approximately 0.05. Therefore, the winding 46 wound in the second operation easily slides the winding 46 wound in the first operation in the radial direction Y on the surface of the insulator teeth 42, allowing the gaps G between the windings 46 to be smoothly closed. Additionally, as described above, a conductor (winding 46) with a small static friction coefficient on the surface of the insulating film 46b can prevent the conductor from getting caught during the winding process, but it also easily slides on the first layer 1L that contacts the surface of the insulator teeth 42, making it more likely for the winding position of the winding 46 to shift. Therefore, when using a conductor with a small static friction coefficient for the insulating film 46b as described above, satisfying the first pitch P1 of the first layer 1L in the first operation (P1 > B) as in the example effectively prevents winding irregularities in the first layer 1L.

[0069] In addition, the insulator 25 in the embodiment contains 15% by weight or more and 45% by weight or less of glass fiber, which increases the dynamic friction coefficient on the surface of the insulator teeth 42. Addition of less than 15% by weight is undesirable because it increases the molding shrinkage rate of the resin material containing glass fiber and reduces the moldability of the insulator 25. Addition of more than 45% by weight is undesirable because it does not significantly increase the dynamic friction coefficient and simply increases manufacturing costs. By adding glass fiber in this way, the insulator 25 prevents the winding 46 wound on the surface of the insulator teeth 42 from slipping, thereby preventing irregular winding of the first layer 1L wound in the first operation and improving the reliability of the conductor wound in the first layer 1L.

[0070] In addition, in the winding process of the embodiment, the conductor wire is wound using a winding machine having a nozzle N, and the control unit C of the winding machine controls the movement amount of the nozzle N (first pitch P1 and second pitch P2), so that in the first operation, a winding portion 45 without winding irregularities can be easily formed at the desired first pitch P1, and in the second operation, the gap G between the windings 46 can be appropriately narrowed at the desired second pitch P2.

[0071] (Modification) In the winding process of the modification, the number of turns of the winding 46 wound in the second operation is four, which differs from the winding process of the embodiment in that the number of turns of the winding 46 in the second operation is two. Fig. 16 is a cross-sectional view for explaining the first operation and the second operation performed in the winding process of the modification. In Fig. 16, in the first layer 1L of the winding section 45, the winding 46 wound in the first operation is indicated by an "F" and the winding 46 wound in the second operation is indicated by an "S."

[0072] 16 , in a first operation in the winding process of the modified example, as in the example, the conductor wire is wound in the first layer 1L of the winding section 55 so that the first pitch P1 satisfies P1 > B, thereby winding the winding 46 so that winding irregularities do not occur in the first layer 1L. In a second operation in the winding process of the modified example, the conductor wire is wound so that the second pitch P2 satisfies P2 < P1, thereby reducing the gap G on the flange portion 43 side (the other end side Y2 in the radial direction Y) between the windings 46 wound in the first operation.

[0073] In the second operation of the modified example, the conductor is wound multiple times up to four turns at the second pitch P2, thereby closing the gaps G between the windings 46 wound in the first operation in order from the flange 43 side, and by closing all of the gaps G, the windings 56 of the first layer 1L are brought into close contact with each other. In the winding process of the modified example, as in the example, the conductor is wound in the second layer 2L and subsequent layers so that the third pitch P3 satisfies P3 < P1, thereby forming the winding portion 55.

[0074] (Effects of the embodiment) As described above, the manufacturing method of the electric motor of the embodiment includes a first operation of winding the conductor from the outer peripheral wall portion 41 side (one end side Y1 in the radial direction Y) of the insulator tooth portion 42 toward the flange portion 43 side (the other end side Y2 in the radial direction Y) in the radial direction Y while leaving a gap G between adjacent windings 46 in the first layer 1L of the winding portion 45, and a second operation of winding the conductor in the first operation after the first operation so as to contact the winding 46 located on the flange portion 43 side (the other end side Y2 in the radial direction Y), thereby moving at least a portion of the winding 46 wound in the first operation toward the outer peripheral wall portion 41 side (one end side Y1 in the radial direction Y) and closing the gap G. By winding the conductor wire on the first layer 1L in the first operation while leaving gaps G between the windings 46 in this way, even if the winding 46 wound on the first layer 1L slips on the surface of the insulator teeth 42, the next winding 46 can smoothly ride over the misaligned winding 46 and be wound appropriately, preventing winding irregularities in the first layer 1L. Also, by winding the conductor wire on the first layer 1L in the second operation so as to reduce the gaps G between the windings 46, the number of turns of the winding 46 in the first layer 1L can be increased, improving the alignment of the windings 46 of the second layer 2L and subsequent layers that are layered on the first layer 1L with reduced gaps G between the windings 46 of the first layer 1L. Therefore, according to this embodiment, for example, there is no need to change the insulator having grooves to prevent winding slippage depending on the outer diameter of the conductor wire, and an increase in the manufacturing cost of the motor 6 can be avoided. Furthermore, according to the embodiment, the winding 46 of the first layer 1L of the winding portion 45 can be prevented from stretching due to winding irregularities, thereby suppressing increases in the resistance value and heat generation of the winding 46 and improving the reliability of the conductor wound in the first layer 1L.

[0075] Furthermore, in the manufacturing method of the electric motor of the embodiment, in the first operation, the conductor wire is wound so that the first pitch P1 satisfies P1 > B. As a result, even if the winding 46 wound in the first layer 1L slips on the surface of the insulator teeth 42, the next winding 46 can smoothly overcome the misaligned winding 46 and be wound appropriately. Therefore, the winding 46 can be wound without any irregularities in the winding in the first layer 1L.

[0076] In the manufacturing method of the electric motor according to the embodiment, in the first operation, the conductor wire is wound so that the first pitch P1 satisfies P1 < 2B. In other words, the outer diameter B and the winding pitch P of the winding wire 46 wound in the first layer 1L of the winding portion 45 satisfy 2B > P. If the first pitch P1 is 2B or greater, the gap G between adjacent winding wires 46 becomes large, and there is a risk that the gap G will not be adequately closed by the second operation. Furthermore, if the first pitch P1 is 2B or greater, the number of turns in the first layer 1L decreases, making it easier for the winding wire 46 of the second layer 2L to enter the gap G between the winding wires 46 in the first layer 1L, which could reduce the alignment of the winding portion 45. These problems can be avoided by ensuring that the first pitch P1 satisfies P1 < 2B.

[0077] In the manufacturing method of the electric motor of the embodiment, in the second operation, the conductor wire is wound so that the second pitch P2 satisfies P2 < P1, thereby making it possible to close the gap G between the windings 46 wound in the first operation by the windings 46 wound in the second operation.

[0078] In the manufacturing method of the electric motor of the embodiment, in the second operation, the conductor is wound so that the second pitch P2 and the outer diameter B of the conductor satisfy the relationship 0≦P2<(B / 2). This allows the gap G between the windings 46 wound in the first operation to be appropriately reduced.

[0079] In the manufacturing method of the electric motor of the embodiment, the second operation involves winding the conductor wire multiple times. By increasing the number of turns in this manner, the effect of reducing the gap G is enhanced and the number of windings 46 wound in the first layer 1L can be increased.

[0080] In addition, in the manufacturing method of the electric motor of the embodiment, the conductor wire is wound so that the third pitch P3 of the winding 46 wound in the second layer 2L and thereafter of the winding portion 45 satisfies P3 < P1. This allows the number of turns in each layer from the second layer 2L onwards to be increased, thereby increasing the space factor of the winding portion 45.

[0081] Furthermore, the outer diameter B of the conductor used in the manufacturing method of the electric motor of the embodiment is the upper limit of the dimensional tolerance, which allows the winding pitch (first pitch P1, second pitch P2, etc.) to be set optimally, thereby most appropriately preventing irregular winding of the winding 46 wound in the first layer 1L in the first operation and most appropriately reducing the gap G between the windings 46 in the second operation.

[0082] Furthermore, when viewed in cross section along the radial direction Y, the insulator teeth 42 of the insulator 25 used in the manufacturing method of the electric motor of the embodiment have a flat surface 42a extending along the radial direction Y and a curved surface 42b formed continuously with the flat surface 42a on the flange 43 side (the other end side Y2 in the radial direction Y) and inclined with respect to the radial direction Y. In the second operation, the winding 46 wound on the curved surface 42b slides along the curved surface 42b toward the flat surface 42a, thereby moving the winding 46 wound on the flange 43 side toward the outer circumferential wall 41 (the one end side Y1 in the radial direction Y). By utilizing the sliding force of the winding 46 wound on the curved surface 42b in this manner, the gap G between the windings 46 wound in the first operation can be smoothly closed.

[0083] Furthermore, the insulating film 46b of the conductor wire (winding 46) used in the manufacturing method of the electric motor of the embodiment contains polyamideimide. This provides the insulating film 46b with high lubricity, which allows the winding 46 wound in the second operation to easily slide the winding 46 wound in the first operation in the radial direction Y on the surface of the insulator teeth 42, thereby smoothly closing the gaps G between the windings 46. Additionally, while the insulating film 46b's high lubricity prevents the conductor wire from getting caught during the winding process, it also makes the first layer 1L, which contacts the surface of the insulator teeth 42, more likely to slip, resulting in misalignment of the winding position of the winding 46. Therefore, by making the first pitch P1 of the first layer 1L in the first operation satisfy P1 > B, as in the embodiment, it is highly effective in preventing winding irregularities in the first layer 1L.

[0084] Furthermore, the insulators 25 used in the manufacturing method of the electric motor of the embodiment contain glass fiber in an amount of 15% by weight or more and 45% by weight or less, which increases the coefficient of dynamic friction on the surfaces of the insulator teeth 42 and prevents the winding 46 wound on the surfaces of the insulator teeth 42 from slipping, thereby preventing irregular winding of the first layer 1L wound in the first operation and improving the reliability of the conductor wound in the first layer 1L.

[0085] In addition, in the manufacturing method of the electric motor of the embodiment, the conductor wire is wound using a winding machine having a nozzle N that supplies the conductor wire. As a result, by having a control unit C of the winding machine control the movement amount (first pitch P1, second pitch P2) of the nozzle N, it is possible to easily form a winding portion 45 without winding irregularities at the desired first pitch P1 in the first operation, and to appropriately close the gaps G between the windings 46 at the desired second pitch P2 in the second operation.

[0086] 6 Electric motor 23 Stator core 25 (25A, 25B) Insulator 31 Yoke portion 32 (32-1 to 32-9) Stator core teeth portion (teeth portion) 41 Outer peripheral wall portion 42 (42-1 to 42-9) Insulator teeth portion (winding drum portion) 42a Flat surface 45, 55 Winding portion 46 Winding 46a Conductor 46b Insulating film 49 Jumper wire B Outer diameter of conductor G Gap P1 First pitch (winding pitch in first operation) P2 Second pitch (winding pitch in second operation) P3 Winding pitch for second and subsequent layers 1L First layer 2L to 8L Second to eighth layers M Length N Nozzle Y Radial direction

Claims

1. A method for manufacturing an electric motor including a stator core having an annular yoke portion and teeth extending radially from the yoke portion; an insulator having a winding drum attached to the teeth portion; and a winding portion formed with multiple layers of wire wound around the teeth portion via the winding drum, the method comprising: a first operation of winding the wire from one end side to the other end side of the winding drum in the radial direction while leaving a gap between adjacent wires in a first layer of the winding portion; and a second operation of winding the wire into the first layer after the first operation so that the wire is in contact with the wire located at the other end side, thereby moving at least a portion of the wire wound in the first operation toward the one end side and closing the gap.

2. A method for manufacturing an electric motor according to claim 1, wherein in the first operation, the conductor is wound so that P1 > B, where P1 is a first pitch that is the winding pitch in the first operation and B is an outer diameter of the conductor.

3. The method for manufacturing an electric motor according to claim 2, wherein in the first operation, the conductor is wound so as to satisfy P1<2B.

4. A method for manufacturing an electric motor according to claim 2, wherein in the second operation, when a second pitch that is the winding pitch in the second operation is P2, the conductor is wound so that P2 < P1 is satisfied.

5. The method for manufacturing an electric motor according to claim 4, wherein in the second operation, the conductor is wound so as to satisfy 0≦P2<(B / 2).

6. The method for manufacturing an electric motor according to claim 1, wherein the second operation involves winding the conductor a plurality of times.

7. A method for manufacturing an electric motor according to claim 1, wherein when a third pitch, which is the winding pitch of the conductor wound in the second and subsequent layers of the winding portion, is defined as P3, the conductor is wound so that P3 < P1 is satisfied.

8. A method for manufacturing an electric motor according to any one of claims 2 to 5, wherein the outer diameter B of the conductor is the upper limit of the dimensional tolerance of the outer diameter.

9. A method for manufacturing an electric motor as set forth in claim 1, wherein, when viewed in a cross section of the winding drum along the radial direction, the winding drum of the insulator has a flat surface extending along the radial direction and an inclined surface formed continuously with the other end side of the flat surface and inclined with respect to the radial direction, and in the second operation, the winding wound on the inclined surface slides along the inclined surface towards the flat surface, thereby moving the winding wound on the other end side towards the one end side.

10. The method for manufacturing an electric motor according to claim 1, wherein the conducting wire has a conductor and an insulating film covering the conductor, and the insulating film contains polyamideimide.

11. The method for manufacturing an electric motor according to claim 1, wherein the insulator contains glass fiber in an amount of 15% by weight or more and 45% by weight or less.

12. The method for manufacturing an electric motor according to claim 1, wherein the conductor wire is wound using a winding machine having a nozzle for supplying the conductor wire.

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