Stator, electric motor, compressor, and air-conditioning device

Abstract

In a stator (2), distributed windings (20) around slots (13) of a stator iron core (10) have: first windings (21) in each of which a first outer layer winding (21a) and a first inner / outer layer winding (21b) are connected in series; and second windings (22) in each of which a first inner layer winding (22a) and a second inner / outer layer winding (22b) are connected in series. The first windings (21) and the second windings (22) are connected in parallel. When a first circle (C11) passes through radially outermost parts of the slots (13), a second circle (C12) passes through the radially innermost part of the stator iron core (10), and a third circle (C13) radially bisects the interval between the first circle (C11) and the second circle (C12), the first inner layer windings (22a) each extend across two of the slots (13), and either the center of gravity or the center in the radial direction of each of the slots (13) is positioned radially inward of the third circle (C13). The windings (20) are formed in a plurality of phases. The first inner layer windings (22a) of the respective phases are disposed at different positions in the circumferential direction.

Description

Stator, Electric Motor, Compressor, and Air Conditioning Apparatus

[0001] The present disclosure relates to a stator, an electric motor, a compressor, and an air conditioning apparatus.

[0002] As winding methods in the stator of an electric motor, there are concentrated windings and distributed windings. Distributed windings are easy to suppress the electromagnetic vibration force generated in the stator, and since the winding coefficient is higher than that of concentrated windings, the magnetic force generated from the rotor can be effectively utilized, and the motor efficiency and motor output can be improved.

[0003] For example, in the case of Patent Document 1, a stator that improves motor efficiency while reducing the manufacturing cost of windings is disclosed in a stator using distributed windings.

[0004] International Publication No. 2020 / 089994

[0005] However, when one-phase windings are connected in parallel, there is a problem that the insertability of the windings decreases depending on the arrangement position of the windings accommodated in the slots.

[0006] An object of the present disclosure is to provide a stator, an electric motor, a compressor, and an air conditioning apparatus that can improve the insertability of windings.

[0007] The stator according to this disclosure comprises a stator core constructed by laminating electromagnetic steel sheets in the axial direction, and a winding wound around the stator core in a distributed winding manner, wherein the stator core has a plurality of slots in the circumferential direction, and the winding has a first winding and a second winding, the first winding and the second winding are connected in parallel, the first winding has a first outer layer winding and a first inner and outer layer winding connected in series, and the second winding has a first inner layer winding and a second inner and outer layer winding connected in series. In a plane perpendicular to the axial direction, when a circle passing through the outermost diameter portion of the slot in the radial direction with respect to the rotation axis of the stator core is defined as the first circle, a circle passing through the innermost diameter portion of the stator core in the radial direction with respect to the rotation axis of the stator core is defined as the second circle, and a circle bisecting the first circle and the second circle in the radial direction with respect to the rotation axis of the stator core is defined as the third circle, the first outer layer winding is arranged across two slots, and in one slot and the other slot, either the radial center or the center of gravity of the first outer layer winding is located on the outer diameter side of the third circle, the first inner and outer layer winding is arranged across two slots, and in one slot, either the radial center or the center of gravity of the first inner and outer layer winding is located on the outer diameter side of the third circle, and in the other slot, either the radial center or the center of gravity of the first inner and outer layer winding is located on the inner diameter side of the third circle, In a stator, the first inner layer winding is arranged across two slots, with either the radial center or the centroid of the first inner layer winding located inward from the third circle in one slot and the other slot, and the second inner and outer layer winding is arranged across two slots, with either the radial center or the centroid of the second inner and outer layer winding located outward from the third circle in one slot and either the radial center or the centroid of the second inner and outer layer winding located inward from the third circle in the other slot, the winding is formed in multiple phases, the winding is arranged such that only windings of the same phase are arranged in one slot, the first inner layer windings of each phase are arranged at different positions in the circumferential direction, and the first inner layer windings of each phase are formed such that no first inner layer windings of other phases are arranged between the slots where the first inner layer windings of one phase are arranged.Furthermore, the electric motor of this disclosure is an electric motor comprising the stator and rotor described above, wherein the rotor has permanent magnets and a rotor core, the rotor core is constructed by laminating electromagnetic steel sheets in the axial direction and is provided with magnet insertion holes, one or more magnet insertion holes are provided for one magnetic pole, and the permanent magnets are inserted to form magnetic poles of number P. Furthermore, the compressor of this disclosure comprises the electric motor described above and a compression mechanism driven by the electric motor. Furthermore, the air conditioning system of this disclosure comprises the compressor described above, a condenser, a pressure reducing device, and an evaporator.

[0008] The stator, motor, compressor, and air conditioning system of this disclosure can improve the ease of winding insertion.

[0009] This is a cross-sectional view of the electric motor according to Embodiment 1. This is a cross-sectional view of the rotor according to Embodiment 1. This is a cross-sectional view of the stator according to Embodiment 1. This is a circuit diagram of the windings according to Embodiment 1. This is a perspective view of the stator according to Embodiment 1. This is a cross-sectional view along line A-A in Figure 3. This is a wiring diagram of the U-phase, V-phase, and W-phase of the windings according to Embodiment 1. This is a cross-sectional view of the stator showing only the W-phase according to Embodiment 1. This is a cross-sectional view of the stator showing only the V-phase according to Embodiment 1. This is a cross-sectional view of the stator showing only the U-phase according to Embodiment 1. This is a cross-sectional view of the stator showing the U-phase, V-phase, and W-phase in a combined state of Figures 8, 9, and 10. This is a cross-sectional view of the stator showing the U-phase, V-phase, and W-phase according to a comparative example. This is a cross-sectional view of the stator showing an example of the arrangement of the first inner layer windings of the U-phase, V-phase, and W-phase according to Embodiment 1. This is a cross-sectional view of the stator showing an example of the arrangement of the first inner layer windings of the U-phase, V-phase, and W-phase according to Embodiment 1. This is a cross-sectional view of the stator showing an example of the arrangement of the first inner layer windings of the U-phase, V-phase, and W-phase according to Embodiment 1. This is a cross-sectional view of a stator showing an example of the arrangement of the first inner layer windings of the U-phase, V-phase, and W-phase according to Embodiment 1. This is a cross-sectional view of a stator showing an example of the arrangement of the first inner layer windings of the U-phase, V-phase, and W-phase according to Embodiment 1. This is a cross-sectional view of a stator showing an example of the arrangement of the first inner layer windings of the U-phase, V-phase, and W-phase according to Embodiment 1. This is a cross-sectional view of a stator showing an example of the arrangement of the first inner layer windings of the U-phase, V-phase, and W-phase according to Embodiment 1. This is a cross-sectional view of a stator showing an example of the arrangement of the first inner layer windings of the U-phase, V-phase, and W-phase according to Embodiment 1. This is a top view showing the windings according to Embodiment 1 inserted into the inserter. This is a side view of the inserter according to Embodiment 1. This is a cross-sectional view of a stator according to Comparative Example 1. This is a circuit diagram of the windings according to Comparative Example 1. This is a cross-sectional view of a stator according to Comparative Example 2. This is a circuit diagram of the windings according to Comparative Example 2. This is a waveform diagram of the current flowing through the U-phase winding of the motor according to Comparative Example 1. This is a waveform diagram of the current flowing through the U-phase winding of the motor according to Comparative Example 2. This is a waveform diagram of the current flowing through the U-phase winding of the motor according to Embodiment 1. These are the numerical data of the current flowing through the U-phase winding of the motors according to Comparative Example 1, Comparative Example 2, and Embodiment 1.This is data on copper loss occurring in the U-phase winding of the motor according to Comparative Example 1, Comparative Example 2, and Embodiment 1. This is a schematic diagram for explaining the impedance of the coil. This is data representing the inductance ratio of the first winding to the second winding in the motor according to Comparative Example 1 and the motor according to Embodiment 1. This is a schematic diagram showing the magnetic flux flowing around the winding when the winding is located on the outer diameter side of the slot. This is a schematic diagram showing the magnetic flux flowing around the winding when the winding is located on the inner diameter side of the slot. This is a cross-sectional view showing an example of a compressor according to Embodiment 3. This is a cross-sectional view showing the configuration of the compression mechanism according to Embodiment 3. This is a diagram schematically showing the configuration of an air conditioning system according to Embodiment 4. This is a refrigerant circuit diagram showing the flow of refrigerant during cooling operation in the air conditioning system according to Embodiment 4. This is a refrigerant circuit diagram showing the flow of refrigerant during heating operation in the air conditioning system according to Embodiment 4. This is an enlarged cross-sectional view showing the configuration of part B enclosed by the dotted line in Figure 3. This is a cross-sectional view of the stator according to Embodiment 2. This is a circuit diagram of the winding according to Embodiment 2. This is a top view showing the winding according to Embodiment 2 inserted into the inserter.

[0010] Embodiments of this disclosure will be described below with reference to the drawings. In the following drawings, identical or corresponding parts are given the same reference numeral, and their descriptions will not be repeated. Also, in the following drawings, including Figure 1, the size relationships of each component may differ from those of the actual components. Furthermore, the forms of components shown in the entire specification are merely examples and are not limited to these descriptions. The direction along the circumference of the circle centered on axis C1, which is the rotation center of the stator 2, is called the "circumferential direction," the direction parallel to axis C1 is called the "axial direction," and the direction perpendicular to axis C1 is called the "radial direction." In addition, the drawings show an xyz Cartesian coordinate system to facilitate understanding between the drawings. The z axis is a coordinate axis parallel to axis C1 of the stator 2. The y axis is a coordinate axis perpendicular to the z axis. The x axis is a coordinate axis perpendicular to both the y axis and the z axis.

[0011] Embodiment 1. <Configuration of the electric motor> Figure 1 is a cross-sectional view of the electric motor 1 according to this embodiment 1. The electric motor 1 shown in Figure 1 consists of a circular stator 2 and a rotor 3 arranged on the inner diameter side of the stator 2 with a gap of 0.25 to 1.25 [mm] between them.

[0012] <Rotor Configuration> Figure 2 is a cross-sectional view of the rotor 3 according to this embodiment 1. The rotor 3 shown in Figure 2 is composed of a circular rotor core 50 and a plurality of permanent magnets 58.

[0013] The rotor core 50 is cylindrical with axis C1 as its center, and is constructed by laminating multiple electromagnetic steel sheets of thickness t in the axial direction and fastening them together with crimping 53 and rivets (not shown). The sheet thickness t is, for example, 0.1 [mm] to 0.7 [mm].

[0014] As shown in Figure 2, the rotor core 50 is provided with a magnet insertion hole 51, a shaft hole 52, and a slit 54 that penetrate in the axial direction.

[0015] One or more magnet insertion holes 51 are provided in the rotor core 50, and permanent magnets 58 are inserted into the magnet insertion holes 51 to form magnetic poles. In Figure 2, six magnet insertion holes 51 are provided, but there are no limit to six magnet insertion holes 51; two or more are sufficient.

[0016] The shaft hole 52 is a hole into which a shaft (not shown) is inserted. The rotating shaft is, for example, a crankshaft 65. Details of the crankshaft 65 will be described later.

[0017] The slit 54 is provided on the outer diameter side of the magnet insertion hole 51. The slit 54 can regulate the flow of magnetic flux from the permanent magnet 58 toward the stator core 10, thereby suppressing the electromagnetic excitation force generated in the stator core 10 during the operation of the electric motor 1. The shape and number of slits 54 are arbitrary, and it is not necessary to provide slits 54 on the rotor core 50.

[0018] The permanent magnet 58 can be a rare-earth magnet mainly composed of neodymium (Nd), iron (Fe), and boron (B), or a ferrite magnet mainly composed of iron oxide (FeO). While either a rare-earth magnet or a ferrite magnet is acceptable, the energy product (product of magnetic flux density B and magnetic field H), one of the indicators of the permanent magnet 58's performance, is higher for rare-earth magnets than for ferrite magnets. Therefore, to ensure the same efficiency for both types of permanent magnets 1, the volume of the permanent magnet 58 can be reduced when using a rare-earth magnet compared to a ferrite magnet.

[0019] The permanent magnets 58 are arranged at regular intervals in the circumferential direction of the rotor core 50. In Figure 2, one permanent magnet 58 is provided for each magnet insertion hole 51, but two or more permanent magnets 58 may be provided for each magnet insertion hole 51.

[0020] <Stator Configuration> Figure 3 is a cross-sectional view of the stator 2 according to this embodiment 1. Figure 42 is an enlarged cross-sectional view showing the configuration of part B enclosed by the dotted line in Figure 3. The stator 2 shown in Figures 3 and 42 is composed of a circular stator core 10, a plurality of windings 20, a plurality of wedges 61, a plurality of slot cells 62, and a plurality of interphase insulating papers (not shown).

[0021] The stator core 10 is an annular shape centered on axis C1, and is constructed by laminating multiple electromagnetic steel sheets with a thickness of 0.1 mm to 0.7 mm in the axial direction and fastening them together by crimping (not shown). The stator core 10 also includes an annular back yoke 11 and multiple teeth 12 that protrude radially inward from the back yoke 11. Furthermore, slots 13, which are insertion spaces for the windings 20, are formed between the teeth 12 in the circumferential direction. In this embodiment 1, four D-cuts are provided on the outer circumferential surface of the back yoke 11 and penetrate through in the axial direction. The number of D-cuts is not limited to four; one or more are sufficient.

[0022] The teeth 12 are arranged at regular intervals in the circumferential direction of the stator core 10, and in this embodiment 1, 18 teeth 12 are provided. However, the number of teeth 12 is not limited to 18.

[0023] The winding 20 is constructed by winding a wire, which consists of a conductor (not shown) mainly composed of copper (Cu) or aluminum (Al) and an insulating coating (not shown) covering the outer circumference of the conductor, around the teeth 12. The main component of the conductor is not limited to copper (Cu) or aluminum (Al), but may also be silver (Ag) or iron (Fe). However, copper (Cu) or aluminum (Al) can be procured at a lower cost than silver (Ag). Also, since copper (Cu) or aluminum (Al) has a lower resistivity than iron (Fe), losses in the winding 20 are reduced, and the efficiency of the motor 1 can be improved. Therefore, by constructing the conductor of the winding 20 in this embodiment 1 from copper (Cu) or aluminum (Al), an inexpensive and highly efficient motor 1 can be constructed.

[0024] In the electric motor 1 according to this embodiment 1, the winding method of the winding 20 is distributed winding. Compared to concentrated winding, in which the winding 20 is wound around one tooth 12, distributed winding, in which the winding is wound across multiple teeth 12, tends to have coil ends that are higher in the axial direction. However, because distributed winding has a higher winding coefficient than concentrated winding, the magnetic flux generated from the permanent magnet 58 can be effectively utilized, resulting in higher efficiency and higher output. Furthermore, compared to concentrated winding, distributed winding can bring the magnetic flux linked to the winding 20 closer to a sinusoidal wave, making it easier to suppress the electromagnetic excitation force generated in the stator core 10, and thus suppressing sound vibrations generated from the electric motor 1.

[0025] As shown in Figure 3, the stator 2 according to this embodiment 1 has a single winding 20 wound across three teeth 12. The detailed configuration of the winding 20 will be described later.

[0026] The wedge 61, slot cell 62, and interphase insulating paper (not shown) are made of, for example, polyethylene terephthalate film (polyester film). The wedge 61 is used to insulate the slot 13 of the stator 2 from the winding 20, and the interphase insulating paper is used to insulate the phases of the winding 20 and the coil ends.

[0027] <Winding Configuration> The configuration of the winding 20 in the stator 2 according to this embodiment 1 will be described. The winding 20 of the stator 2 according to this embodiment 1 is a three-phase system consisting of U-phase, V-phase, and W-phase. However, in Figure 3, only the U-phase is shown for explanatory purposes, and the arrangement of the V-phase and W-phase will be described later.

[0028] Figure 4 is a circuit diagram of the winding 20 according to this embodiment 1. As shown in Figure 4, the winding 20 according to this embodiment 1 has a first winding 21 and a second winding 22 connected in parallel.

[0029] As shown in Figures 3 and 4, the first winding 21 consists of a winding housed on the outer diameter side of the slot 13 (hereinafter referred to as the "first outer layer winding 21a"), a winding housed on the inner diameter side of the slot 13 and the outer diameter side of the slot 13 (hereinafter referred to as the "first inner / outer layer winding 21b"), and a winding housed on the inner diameter side of the slot 13 and the outer diameter side of the slot 13 (hereinafter referred to as the "third inner / outer layer winding 21c"), all connected in series. The first outer layer winding 21a, the first inner / outer layer winding 21b, and the third inner / outer layer winding 21c are each bundles of multiple wires.

[0030] As shown in Figure 3, the first outer layer winding 21a, the first inner and outer layer winding 21b, and the third inner and outer layer winding 21c are each wound at a 3-slot pitch, or in other words, every 3 slots. Slot pitch refers to the circumferential angle between adjacent slots. In this embodiment 1, the stator 2 has 18 slots 13 formed at equal intervals in the stator core 10, so the slot pitch is 360 degrees / 18 = 20 degrees in mechanical angle.

[0031] In other words, the same first outer layer winding 21a is inserted into the third slot from the slot 13 into which the first outer layer winding 21a is inserted. To put it another way, the first outer layer winding 21a, the first inner / outer layer winding 21b, and the third inner / outer layer winding 21c are wound so as to span three teeth 12.

[0032] Since the windings 20 are wound at a 3-slot pitch, each winding 20 is wound over a mechanical angle of 360 degrees × 3 / 18 = 60 degrees. In other words, the coil pitch is a mechanical angle of 60 degrees. The coil pitch refers to the circumferential angle from one coil side 210 of the winding 20 to the other coil side 210 of the same winding 20, which will be described later.

[0033] Furthermore, the first outer layer winding 21a, the first inner and outer layer winding 21b, and the third inner and outer layer winding 21c are each arranged at intervals of 3 slot pitches.

[0034] The second winding 22 consists of a winding housed on the inner diameter side of the slot 13 (hereinafter referred to as the "first inner layer winding 22a"), windings arranged every three slot pitches from the first inner layer winding 22a and housed on the inner diameter side of the slot 13 and on the outer diameter side of the slot 13 (hereinafter referred to as the "second inner and outer layer winding 22b"), and windings arranged every three slot pitches from the second inner and outer layer winding 22b and housed on the inner diameter side of the slot 13 and on the outer diameter side of the slot 13 (hereinafter referred to as the "fourth inner and outer layer winding 22c"), all connected in series. The first inner layer winding 22a, the second inner and outer layer winding 22b, and the fourth inner and outer layer winding 22c are each bundles of multiple wires.

[0035] As shown in Figure 3, in the stator core 10 according to this embodiment 1, a first circle C11, a second circle C12, and a third circle C13 are defined. Specifically, in a plane perpendicular to the axial direction, the first circle C11 is a virtual circle centered on the axis C1 of the stator core 10 and passing through the outermost diameter portion of the slot 13 in the radial direction. The second circle C12 is a virtual circle centered on the axis C1 of the stator core 10 and passing through the innermost diameter portion of the stator core 10 in the radial direction. The third circle C13 is a virtual circle that bisects the first circle C11 and the second circle C12 in the radial direction, centered on the axis C1 of the stator core 10.

[0036] The first outer layer winding 21a provided on the first winding 21 will now be described. As shown in Figure 3, the first outer layer winding 21a is arranged across two slots 13. In one slot 13 and the other slot 13, either the radial center or the centroid of the first outer layer winding 21a is located on the outer diameter side of the third circle C13.

[0037] The first inner and outer layer windings 21b provided on the first winding 21 will now be described. As shown in Figure 3, the first inner and outer layer windings 21b are arranged across two slots 13, with either the radial center or the centroid of the first inner and outer layer windings 21b located on the outer diameter side of the third circle C13 in one slot 13, and either the radial center or the centroid of the first inner and outer layer windings 21b located on the inner diameter side of the third circle C13 in the other slot 13.

[0038] Next, we will describe the third inner and outer layer winding 21c provided on the first winding 21. As shown in Figure 3, the third inner and outer layer winding 21c is arranged across two slots 13, with either the radial center or the centroid of the third inner and outer layer winding 21c located on the outer diameter side of the third circle C13 in one slot 13, and either the radial center or the centroid of the third inner and outer layer winding 21c located on the inner diameter side of the third circle C13 in the other slot 13.

[0039] The first inner layer winding 22a provided in the second winding 22 will now be described. As shown in Figure 3, the first inner layer winding 22a is arranged across two slots 13, and in one slot 13 and the other slot 13, either the radial center or the centroid of the first inner layer winding 22a is located on the inner diameter side of the third circle C13.

[0040] The second inner and outer layer winding 22b provided on the second winding 22 will now be described. As shown in Figure 3, the second inner and outer layer winding 22b is arranged across two slots 13, with either the radial center or the centroid of the second inner and outer layer winding 22b located on the outer diameter side of the third circle C13 in one slot 13, and either the radial center or the centroid of the second inner and outer layer winding 22b located on the inner diameter side of the third circle C13 in the other slot 13.

[0041] A description will be given of the fourth inner and outer layer winding 22c provided in the second layer winding 22. As shown in FIG. 3, the fourth inner and outer layer winding 22c is arranged across two slots 13, and either the radial center or the centroid of the fourth inner and outer layer winding 22c is located on the outer diameter side of the third circle C13 in one slot 13, and either the radial center or the centroid of the fourth inner and outer layer winding 22c is located on the inner diameter side of the third circle C13 in the other slot 13.

[0042] That is, in the stator 2 according to the first embodiment, six windings 20 are provided per phase.

[0043] In the stator 2 according to the first embodiment, a form in which six windings 20 are provided per phase has been shown, but the total number of windings 20 is not limited to six. The first winding 21 only needs to be provided with a first outer layer winding 21a and a first inner and outer layer winding 21b, respectively. Similarly, the second winding 22 only needs to be provided with a first inner layer winding 22a and a second inner and outer layer winding 22b, respectively. In this case, the total number of windings 20 per phase is four.

[0044] FIG. 5 is a perspective view of the stator 2 according to the first embodiment. FIG. 6 is a cross-sectional view taken along line A-A in FIG. 3.

[0045] As shown in FIGS. 5 and 6, each winding 20 has a coil side 210, a coil end 211, and a coil root 212. The coil side 210 is a portion inserted into the slot 13. The coil end 211 is a portion formed along the axial end surface of the stator core 10. The coil root 212 is a portion that protrudes axially from the stator core 10 and is formed between the coil side 210 and the coil end 211.

[0046] A gap portion 213 is formed between the axial end surface of the stator core 10 and the coil end 211. If the axial height of the gap portion 213 is Hc, it is desirable to satisfy 4 ≤ Hc ≤ 8 [mm]. By satisfying 4 ≤ Hc [mm], in the winding process described later, while ensuring the mechanical strength of the blade 201 provided in the inserter 200, the insertion of the blade 201 into the gap portion 213 becomes easy, so that the productivity of winding can be improved.

[0047] Also, in the six-pole and eighteen-slot motor 1, it is common to configure it with three windings 20 per phase. However, in this case, since the winding 20 per unit becomes large, Hc tends to bulge to 8 [mm] or more. In the stator 2 according to the first embodiment, since it is configured with six windings 20 per phase, the winding 20 per unit can be made smaller. That is, the stator 2 according to the first embodiment can satisfy Hc ≤ 8 [mm]. As a result, a significant increase in the circumferential length of the winding 20 can be suppressed, and an increase in copper loss generated in the winding can be suppressed.

[0048] As shown in FIG. 3, by winding the first winding 21 and the second winding 22 around the stator core 10, six windings 20 per phase are wound around the stator 2. Each winding 20 is wound with a three-slot pitch.

[0049] The stator 2 according to the first embodiment has six windings 20 wound per phase, which is the same number as the number of poles of the rotor 3 (the rotor 3 according to the first embodiment has six poles). Since the winding 20 of the stator 2 according to the first embodiment is wound with a three-slot pitch, the coil pitch of the stator 2 is 360 [degrees] × 3 / 18 = 60 [degrees] in mechanical angle. The coil pitch represents the circumferential angle from one coil side 210 of the winding 20 to the other coil side 210 of the same winding 20. In other words, one winding 20 is wound over a mechanical angle of 60 [degrees]. Also, the pole pitch of the rotor 3 is 360 [degrees] / 6 = 60 [degrees] in mechanical angle. In other words, adjacent poles in the rotor 3 are arranged at intervals of 60 [degrees] in mechanical angle.

[0050] In the electric motor 1 according to this embodiment 1, the coil pitch of the stator 2 and the magnetic pole pitch of the rotor 3 both coincide at a mechanical angle of 60 degrees. This type of winding configuration, where the coil pitch and magnetic pole pitch are equal, is called "full-slot winding." That is, coils of the same phase are arranged in the same slot. In the electric motor 1 according to this embodiment 1, the primary winding coefficient Kw1 is 1. The primary winding coefficient Kw1 is an index that shows the proportion of the magnetic flux generated from the permanent magnet 58 on the rotor 3 that can contribute as the effective magnetic flux of the fundamental wave linked to the winding 20 of the stator 2. In other words, in the electric motor 1 according to this embodiment 1, the primary winding coefficient Kw1 can be maximized to 1, so the magnetic flux of the permanent magnet 58 can be effectively utilized, and the efficiency of the electric motor 1 can be increased.

[0051] In the motor 1 according to this embodiment 1, the total number of slots 13 in the stator 2, the number of phases M, and the number of poles P in the rotor 3 are S / (MP) = 18 / (3 × 6) = 1. That is, the number of slots 13 per phase and per pole (hereinafter referred to as "number of slots per pole per phase") is 1. Having an integer number of slots per pole per phase reduces the electromagnetic excitation force generated in the stator 2 during the operation of the motor 1.

[0052] Figure 7 is a wiring diagram of the U-phase, V-phase, and W-phase of the winding 20 according to this first embodiment. As shown in Figure 7, the first winding 21 and the second winding 22, which are connected in parallel, are configured in a Y-connection connected to the neutral point N. In Figure 7, the first winding 21U and second winding 22U of the U-phase, the first winding 21V and second winding 22V of the V-phase, the first winding 21W and second winding 22W of the W-phase are shown, respectively.

[0053] The electric motor 1 according to this embodiment 1 has 6 poles P and a total of 18 slots S, and is fully wound. In this winding configuration, the primary winding coefficient Kw1 is 1, and the tertiary winding coefficient Kw3 is also 1.

[0054] In an electric motor 1 with a tertiary winding coefficient Kw3 of 1, if the U-phase, V-phase, and W-phase are configured in a delta connection, a current (hereinafter referred to as "circulating current") will be generated that circulates between the U-phase, V-phase, and W-phase. During operation of the electric motor 1, the circulating current does not contribute to the torque generated by the rotor 3 and becomes a factor that increases copper loss in the winding 20.

[0055] Therefore, in the motor 1 according to this embodiment 1, by configuring it in a Y-connection, a closed loop is not formed between the U-phase, V-phase, and W-phase, thus interrupting the current path circulating between the U-phase, V-phase, and W-phase. As a result, since no circulating current is generated in the Y-connection, the efficiency of the motor 1 can be increased.

[0056] Next, the arrangement of the U-phase, V-phase, and W-phase windings 20 in the stator 2 according to this embodiment 1 will be described in detail. Figure 8 shows the arrangement of the W-phase winding 20, Figure 9 shows the arrangement of the V-phase winding 20, and Figure 10 shows the arrangement of the U-phase winding 20. Note that these arrangements are just examples and are not limited to this configuration; for example, Figure 8 could be the U-phase, Figure 9 the W-phase, and Figure 10 the V-phase. When each phase is shown separately, they will be referred to as the first inner winding 22aw for the W phase, the first inner winding 22av for the V phase, the first inner winding 22au for the U phase, the first outer winding 21aw for the W phase, the first outer winding 21av for the V phase, the first outer winding 21au for the U phase, the second inner and outer winding 22bw for the W phase, the second inner and outer winding 22bv for the V phase, and the second inner and outer winding 22bu for the U phase. When the phases are not shown separately, they will be described as the first inner winding 22a, the first outer winding 21a, and the second inner and outer winding 22b.

[0057] In Figure 8, the first inner and outer layer winding 21bw, the third inner and outer layer winding 21cw, and the fourth inner and outer layer winding 22cw of the W phase are shown; in Figure 9, the first inner and outer layer winding 21bv, the third inner and outer layer winding 21cv, and the fourth inner and outer layer winding 22cv of the V phase are shown; and in Figure 10, the first inner and outer layer winding 21bu, the third inner and outer layer winding 21cu, and the fourth inner and outer layer winding 22cu of the U phase are shown.

[0058] As shown in Figures 8, 9, and 10, the first inner layer windings 22aw, 22av, and 22au of each phase are formed across two slots 13 at different positions in the circumferential direction. In this first inner layer winding 22a, either the radial center or the centroid of the first inner layer winding 22a in one slot 13 and the other slot 13 is located radially inward from the third circle C13.

[0059] As shown in Figure 8, within the slot 13 where the first inner layer winding 22aw of the W phase is located, either the first outer layer winding 21aw of the same phase or the second inner / outer layer winding 22bw of the same phase is always located on the radial outer diameter side of the first inner layer winding 22aw of the W phase.

[0060] Furthermore, as shown in Figure 9, within the slot 13 where the first inner layer winding 22av of the V phase is arranged, either the first outer layer winding 21av of the V phase of the same phase or the second inner / outer layer winding 22bv of the V phase of the same phase is always arranged on the radial outer diameter side of the first inner layer winding 22av of the V phase.

[0061] Furthermore, as shown in Figure 10, within the slot 13 where the first inner layer winding 22au of the U phase is arranged, either the first outer layer winding 21au of the U phase of the same phase or the second inner / outer layer winding 22bu of the U phase of the same phase is always arranged on the radial outer diameter side of the first inner layer winding 22au of the U phase.

[0062] Figure 11 shows the result when Figures 8, 9, and 10 are combined. As shown in Figure 11, the windings 20 of the U-phase, V-phase, and W-phase of the stator 2 according to this embodiment 1 are arranged. As is clear from comparing Figure 11 with the first inner layer windings 22aw, 22av, and 22au of each phase in Figures 8, 9, and 10, the first inner layer windings 22aw, 22av, and 22au of each phase are all arranged in different positions in the circumferential direction.

[0063] Therefore, as shown in Figure 11, there are no overlapping locations in the radial direction of the first inner layer windings 22aw, 22av, and 22au of each phase in Figures 8, 9, and 10, and no first inner layer windings 22aw, 22av, and 22au of other phases are placed between the slots 13 where the first inner layer windings 22aw, 22av, and 22au of one phase are placed. In Figure 11, in order to clarify the formation positions in the circumferential direction of the first inner layer winding 22au of the U phase, the first inner layer winding 22av of the V phase, and the first inner layer winding 22aw of the W phase, the formation positions in the circumferential direction are shown extended to the inner diameter side.

[0064] In this way, the first inner layer windings 22aw, 22av, and 22au of each phase are arranged such that in the circumferential direction between the slots 13 where one of the first inner layer windings 22aw, 22av, and 22au of each phase is located, the remaining two first inner layer windings 22aw, 22av, and 22au of each phase located on the inner diameter side of the third circle C13 are not arranged. This enables a distributed arrangement of the first inner layer windings 22aw, 22av, and 22au of each phase located on the inner diameter side of the third circle C13, thereby improving the insertability of the windings 20 and wedges 61 into the slots 13.

[0065] Furthermore, since the first inner layer windings 22aw, 22av, and 22au of each phase are arranged at different positions in the circumferential direction, in a location other than the slot 13 into which the first inner layer winding 22a is inserted, in the portion 211a of the coil end 211a (the area enclosed by hatching in Figures 8, 9, and 10) of the first inner layer winding 22a that spans between the said slots 13, one of the windings 20 of the other phases, either the first outer layer winding 21a, the first inner / outer layer winding 21b, the second inner / outer layer winding 22b, the third inner / outer layer winding 21c, or the fourth inner / outer layer winding 22c, is always arranged on the radial outer diameter side, as is clear from Figure 11.

[0066] Because the first inner layer winding 22a is positioned in this manner, if a force of a certain magnitude is applied to the first inner layer winding 22a from the inner diameter side to the outer diameter side after it has been inserted into the slot 13, the amount by which the first inner layer winding 22a moves toward the outer diameter side is small compared to the other windings, namely the first outer layer winding 21a, the first inner / outer layer winding 21b, the second inner / outer layer winding 22b, the third inner / outer layer winding 21c, and the fourth inner / outer layer winding 22c, because one of the other windings, namely the first outer layer winding 21a, the first inner / outer layer winding 21b, the second inner / outer layer winding 22b, the third inner / outer layer winding 21c, and the fourth inner / outer layer winding 22c, is present.

[0067] In contrast, as a comparative example, Figure 12 shows a case where, when inserting the U-phase, V-phase, and W-phase windings 20, the first inner layer winding 22au of the U-phase, the first inner layer winding 22av of the V-phase, and the first inner layer winding 22aw of the W-phase are arranged to overlap in the circumferential direction. In Figure 12, in order to clarify the formation positions of the first inner layer windings 22au of the U-phase, 22av of the V-phase, and 22aw of the W-phase in the circumferential direction, their circumferential formation positions are shown extended towards the inner diameter side.

[0068] As is clear from Figure 12, when the first inner layer winding 22au of the U phase, the first inner layer winding 22av of the V phase, and the first inner layer winding 22aw of the W phase are arranged to overlap in the circumferential direction, the windings 20 located on the inner diameter side of the third circle C13 will be arranged to have varying density. Therefore, at the locations where each first inner layer winding 22a overlaps in the radial direction, the rigidity of the windings 20 increases, making it difficult to insert the windings 20 and the wedge 61 into the slot 13.

[0069] Note that the arrangement of the U-phase, V-phase, and W-phase windings 20 in this embodiment 1 shown in Figure 11 (Figures 8, 9, and 10) is just one example, and there are a total of nine arrangement patterns for the number of slots 13. All nine arrangement examples in this embodiment 1 are shown in Figures 13, 14, 15, 16, 17, 18, 19, 20, and 21. Note that in Figures 13 to 21, the circumferential formation positions of the first inner layer winding 22au of the U-phase, the first inner layer winding 22av of the V-phase, and the first inner layer winding 22aw of the W-phase are shown extended to the inner diameter side in order to clarify their respective formation positions.

[0070] In Figures 13, 14, 15, 16, 17, 18, 19, 20, and 21, for explanatory purposes, only the first inner layer winding 22au of the U phase, the first inner layer winding 22av of the V phase, and the first inner layer winding 22aw of the W phase are shown, and the other windings 20, namely the first outer layer winding 21a, the first inner / outer layer winding 21b, the second inner / outer layer winding 22b, the third inner / outer layer winding 21c, and the fourth inner / outer layer winding 22c, are omitted. Note that Figure 13 shows the same arrangement pattern as Figure 11 (Figures 8, 9, and 10).

[0071] As shown in Figures 13 to 21, in all of these, the first inner layer windings 22aw, 22av, and 22au of the U, V, and W phases are all positioned at different locations in the circumferential direction. Therefore, as in the case described above, the first inner layer windings 22aw, 22av, and 22au of each phase do not overlap in the radial direction, and the structure is such that the first inner layer windings 22aw, 22av, and 22au of other phases are not positioned between the slots 13 where the first inner layer windings 22aw, 22av, and 22au of one phase are located.

[0072] Furthermore, within the slot 13 where the first inner layer winding 22a is located, either a first outer layer winding 21a of the same phase or a second inner / outer layer winding 22b of the same phase is always located on the radial outer diameter side of the first inner layer winding 22a.

[0073] Furthermore, in areas other than the slot 13 into which the first inner layer winding 22a is inserted, in the portion 211a of the coil end 211a of the first inner layer winding 22a that spans between the said slots 13 (the portion enclosed by hatching in each figure), one of the windings 20 of the other phases—the first outer layer winding 21a, the first inner / outer layer winding 21b, the second inner / outer layer winding 22b, the third inner / outer layer winding 21c, or the fourth inner / outer layer winding 22c—is always arranged on the radial outer diameter side. These are just examples, and naturally, if the number of slots 13 is different (for example, if the size of the stator core 10 of the stator 2 is different, or if the stator core 10 of the stator 2 is the same size but the number of slots 13 is different), it is possible to arrange them based on the same idea.

[0074] <Production Method for Windings> The production method for the winding 20 according to this embodiment 1 will now be described. Figure 22 is a top view showing the winding 20 according to this embodiment 1 inserted into the inserter 200. To insert the winding 20 into the slot 13, an inserter 200 as shown in Figure 22 is used.

[0075] Figure 23 is a side view of the inserter 200 according to this first embodiment. As shown in Figures 22 and 23, the inserter 200 comprises a plurality of blades 201 and a connecting portion 202 that connects each blade 201. The number of blades 201 is the same as the number of slots 13, and they are arranged at equal intervals in the circumferential direction with respect to the axis C1, and they extend axially from the connecting portion 202.

[0076] As shown in Figure 22, the first outer layer winding 21a, the first inner and outer layer winding 21b, the third inner and outer layer winding 21c, the first inner layer winding 22a, the second inner and outer layer winding 22b, and the fourth inner and outer layer winding 22c are mounted on the inserter 200. The windings are mounted on the inserter 200 in the following order: first inner layer winding 22a, second inner and outer layer winding 22b, fourth inner and outer layer winding 22c, third inner and outer layer winding 21c, first inner and outer layer winding 21b, and first outer layer winding 21a. In other words, after being mounted on the inserter 200, the first inner layer winding 22a, the second inner / outer layer winding 22b, the fourth inner / outer layer winding 22c, the third inner / outer layer winding 21c, the first inner / outer layer winding 21b, and the first outer layer winding 21a are arranged in a stepped manner, overlapping upwards in the z-axis direction, as shown in Figure 22. Each winding 20 is stretched across the three blades 201. Note that Figure 22 shows an example of the case shown in Figure 3.

[0077] The inserter 200 is inserted into the inner diameter side of the stator core 10 so that each blade 201 faces the radially inward side of the teeth 12, and then pulled out axially. As a result, each winding stretched across the blade 201 is housed in the slot 13 in the order of first outer layer winding 21a, first inner and outer layer winding 21b, third inner and outer layer winding 21c, fourth inner and outer layer winding 22c, second inner and outer layer winding 22b, and first inner layer winding 22a, and wound around the stator core 10.

[0078] The windings 20 for the U-phase, V-phase, and W-phase are arranged as follows: first, one of the windings 20 for any one phase, for example the W-phase winding 20, is inserted into the slot 13 by the inserter 200; then, one of the remaining two windings 20 for any one phase, for example the V-phase winding 20, is inserted into the slot 13 by the inserter 200; and then, the remaining one winding 20 for any one phase, for example the U-phase winding 20, is inserted into the slot by the inserter 200.

[0079] Furthermore, as shown in Figures 11 and 13 to 21, by adjusting the circumferential mounting position of the windings 20 in the inserter 200 so that the first inner layer winding 22au of the U phase, the first inner layer winding 22av of the V phase, and the first inner layer winding 22aw of the W phase do not overlap radially when inserted into the slot 13, the insertion of the winding 20 of the last phase to be inserted becomes easier.

[0080] Furthermore, as shown in Figures 11 and 13 to 21, the windings mounted on the inserter 200—the first inner layer winding 22a, the first outer layer winding 21a, the first inner / outer layer winding 21b, the second inner / outer layer winding 22b, the third inner / outer layer winding 21c, and the fourth inner / outer layer winding 22c—are arranged in the same order circumferentially in each phase. Therefore, after mounting one phase's winding 20 to the inserter 200, the circumferential arrangement of the winding 20 in the slot 13 can be determined simply by rotating it circumferentially to match the circumferential position of the slot 13, thereby improving work efficiency.

[0081] Specifically, as shown in Figures 8, 9, and 10, the first inner layer winding 22a, first outer layer winding 21a, first inner / outer layer winding 21b, second inner / outer layer winding 22b, third inner / outer layer winding 21c, and fourth inner / outer layer winding 22c of each phase are arranged in the same order in the circumferential direction. Therefore, first, in order to form the W-phase winding 20 shown in Figure 8, the first inner layer winding 22a, first outer layer winding 21a, first inner / outer layer winding 21b, second inner / outer layer winding 22b, third inner / outer layer winding 21c, and fourth inner / outer layer winding 22c are fitted into the slot 13 by an inserter 200 which is appropriately installed to form the W-phase winding 20.

[0082] Next, similarly, the first inner layer winding 22a, the first outer layer winding 21a, the first inner / outer layer winding 21b, the second inner / outer layer winding 22b, the third inner / outer layer winding 21c, and the fourth inner / outer layer winding 22c are installed on the inserter 200 to form the V-phase winding 20 shown in Figure 9. In this case, the V-phase winding 20 shown in Figure 9 can be formed by rotating the inserter 200 four slots clockwise in the circumferential direction from its previous position and then inserting it into slot 13. Similarly, the U-phase winding 20 shown in Figure 10 can be formed by performing the same procedure, rotating the inserter 200 seven slots clockwise in the circumferential direction from its previous position and then inserting it into slot 13.

[0083] <Regarding Comparative Examples> In order to explain the effects of the electric motor 1 according to this embodiment 1, the configurations and effects of Comparative Example 1 and Comparative Example 2 will be described.

[0084] <Explanation of Comparative Example 1> Figure 24 is a cross-sectional view of the stator 2a according to Comparative Example 1. Figure 25 is a circuit diagram of the winding 20a according to Comparative Example 1. Similar to Figures 3 and 4, only the U phase will be shown and explained in Figures 24 and 25.

[0085] As shown in Figure 25, in Comparative Example 1, the winding 20a has the first winding 31 and the second winding 32 connected in parallel.

[0086] As shown in Figures 24 and 25, the first winding 31 consists of a winding housed on the outer diameter side of the slot 13 (hereinafter referred to as "first outer layer winding 31a"), windings arranged every six slot pitches from the first outer layer winding 31a and housed on the outer diameter side of the slot 13 (hereinafter referred to as "second outer layer winding 31b"), and windings arranged every six slot pitches from the second outer layer winding 31b and housed on the outer diameter side of the slot 13 (hereinafter referred to as "third outer layer winding 31c"), all connected in series.

[0087] The second winding 32 consists of a winding housed on the inner diameter side of the slot 13 (hereinafter referred to as "first inner layer winding 32a"), windings arranged every six slot pitches from the first inner layer winding 32a and housed on the inner diameter side of the slot 13 (hereinafter referred to as "second inner layer winding 32b"), and windings arranged every six slot pitches from the second inner layer winding 32b and housed on the inner diameter side of the slot 13 (hereinafter referred to as "third inner layer winding 32c"), all connected in series.

[0088] <Explanation of Comparative Example 2> Figure 26 is a cross-sectional view of the stator 2b according to Comparative Example 2. Figure 27 is a circuit diagram of the winding 20b according to Comparative Example 2. Similar to Figures 3 and 4, only the U phase will be shown and explained in Figures 26 and 27.

[0089] As shown in Figure 27, in Comparative Example 2, the winding 20b has the first winding 41 and the second winding 42 connected in series.

[0090] As shown in Figures 26 and 27, the first winding 41 consists of a winding housed on the outer diameter side of the slot 13 (hereinafter referred to as "first outer layer winding 41a"), windings arranged every six slot pitches from the first outer layer winding 41a and housed on the outer diameter side of the slot 13 (hereinafter referred to as "second outer layer winding 41b"), and windings arranged every six slot pitches from the second outer layer winding 41b and housed on the outer diameter side of the slot 13 (hereinafter referred to as "third outer layer winding 41c"), all connected in series.

[0091] The second winding 42 consists of a winding housed on the inner diameter side of the slot 13 (hereinafter referred to as "first inner layer winding 42a"), windings arranged every six slot pitches from the first inner layer winding 42a and housed on the inner diameter side of the slot 13 (hereinafter referred to as "second inner layer winding 42b"), and windings arranged every six slot pitches from the second inner layer winding 42b and housed on the inner diameter side of the slot 13 (hereinafter referred to as "third inner layer winding 42c"), all connected in series.

[0092] <Effects of the motor according to this embodiment 1> The effects of the motor 1 according to this embodiment 1 will be explained. Figure 28 is a waveform diagram of the current flowing through the U-phase winding of motor 1a according to comparative example 1. Figure 29 is a waveform diagram of the current flowing through the U-phase winding of motor 1b according to comparative example 2. Figure 30 is a waveform diagram of the current flowing through the U-phase winding of motor 1 according to this embodiment 1. Figures 28 to 30 all show the waveform of the current flowing through the U-phase winding calculated by numerical analysis when the rotational speed of the rotor 3 is 90 [rpm] and the torque of the rotor 3 is 15 [Nm].

[0093] As shown in Figure 28, in the motor 1a according to Comparative Example 1, there is a significant difference between the waveform of the current Iu31 flowing through the first winding 31 and the waveform of the current Iu32 flowing through the second winding 32. Specifically, the current Iu32 flowing through the second winding 32 is larger than the current Iu31 flowing through the first winding 41.

[0094] On the other hand, as shown in Figure 29, in the motor 1b according to Comparative Example 2, the waveform of the current Iu41 flowing through the first winding 41 and the waveform of the current Iu42 flowing through the second winding 42 are identical. This is because, in the winding according to Comparative Example 2, the first winding 41 and the second winding 42 are connected in series, so Iu41 = Iu42 holds true.

[0095] Furthermore, as shown in Figure 30, in the motor 1 according to this embodiment 1, the waveform of the current Iu21 flowing through the first winding 21 and the waveform of the current Iu22 flowing through the second winding 22 are generally identical. In other words, although the winding 20 according to this embodiment 1 is connected in parallel, similar to the winding 20a according to comparative example 1, the motor 1 according to this embodiment 1 can suppress the current imbalance between the first winding 21 and the second winding 22 compared to the motor 1a according to comparative example 1.

[0096] Figure 31 shows numerical data of the current flowing through the U-phase windings of the electric motors 1a, 1b, and 1 according to Comparative Example 1, Comparative Example 2, and Embodiment 1.

[0097] As shown in Figure 31, when calculating the ratio Iu31 / Iu32, which is the ratio of the current Iu31 in the first winding 31 to the current Iu32 in the second winding 32 of the electric motor 1a according to Comparative Example 1, we get Iu31 / Iu32 = (Iu3 × 0.472) / (Iu3 × 0.730) = 64.7 [%].

[0098] In contrast, as shown in Figure 31, when calculating the ratio Iu21 / Iu22, which is the ratio of the current Iu21 in the first winding 21 to the current Iu22 in the second winding 22 in the motor 1 according to this embodiment 1, we get Iu21 / Iu22 = (Iu2 × 0.491) / (Iu2 × 0.509) = 96.5 [%].

[0099] In other words, compared to the motor 1a according to Comparative Example 1, the motor 1 according to this embodiment 1 can bring the ratio of the current Iu21 in the first winding 21 to the current Iu22 in the second winding 22 closer to 100%, and it can be seen that the imbalance in current between the first winding 21 and the second winding 22 can be suppressed.

[0100] Next, the effects of suppressing the current imbalance between the first winding 21 and the second winding 22 in the motor 1 according to this embodiment 1 will be explained. Figure 32 shows the data of copper loss occurring in the U-phase windings of Comparative Example 1, Comparative Example 2, and motors 1a, 1b, and 1 according to this embodiment 1. Figure 32 shows the copper loss occurring in the U-phase windings calculated by numerical analysis when the rotational speed of the rotor 3 is 90 [rpm] and the torque of the rotor 3 is 15 [Nm].

[0101] As shown in Figure 32, in the motor 1a according to Comparative Example 1, a copper loss W3 of 73.7 [W] occurs in the U-phase winding 20a. In contrast, in the motor 1b according to Comparative Example 2, a copper loss W4 of 40 [W] occurs in the U-phase winding 20b, which is a 45.7 [%] reduction compared to the copper loss that occurs in the motor 1a according to Comparative Example 1. In the motor 1 according to this embodiment 1, a copper loss W2 of 40.5 [W] occurs in the U-phase winding 20, which is reduced to a value close to the copper loss that occurs in the motor 1b according to Comparative Example 2.

[0102] We will now analyze the occurrence of copper loss in detail. As shown in Figure 32, in the motor 1a according to Comparative Example 1, the copper loss W31 occurring in the first winding 31 is 21.7 [W], while the copper loss W32 occurring in the second winding 32 is 52.0 [W]. The reason why the copper loss W32 occurring in the second winding 32 is larger is that the current Iu32 flowing through the second winding 32 is larger, as shown in Figure 31.

[0103] On the other hand, as shown in Figure 32, in the motor 1b according to Comparative Example 2, the copper loss W41 generated in the first winding 41 is 20.0 [W], while the copper loss W42 generated in the second winding 42 is 20.0 [W]. In the stator 2b according to Comparative Example 2, since the first winding 41 and the second winding 42 are connected in series, no current imbalance occurs, and therefore the copper loss W41 generated in the first winding 41 and the copper loss W42 generated in the second winding 42 are the same value.

[0104] Furthermore, as shown in Figure 32, in the motor 1 according to this embodiment 1, the copper loss W21 generated in the first winding 21 is 19.5 [W], while the copper loss W22 generated in the second winding 22 is 21.0 [W]. Thus, in the motor 1 according to this embodiment 1, even though the first winding 21 and the second winding 22 are connected in parallel, the values ​​of the copper loss W21 generated in the first winding 21 and the copper loss W22 generated in the second winding 22 are similar, and the effect of current imbalance is reduced.

[0105] Next, the reason why current imbalance can be suppressed in the electric motor 1 according to this embodiment 1 will be explained. Figure 33 is a schematic diagram for explaining the impedance of the coil.

[0106] As shown in Figure 33, the equivalent circuit of the first winding 21 can be considered as a series connection of the first winding resistance R21 [Ω] and the first winding inductance L21 [H]. Similarly, the equivalent circuit of the second winding 22 can be considered as a series connection of the second winding resistance R22 [Ω] and the second winding inductance L22 [H]. Here, the first winding resistance R21 and the second winding resistance R22 are determined by the material, diameter, and circumference of the wires constituting the winding 20. The first winding inductance L21 and the second winding inductance L22 are determined by the number of turns of the winding 20 and the flux linkage. The first winding impedance Z21 and the second winding impedance Z22 are expressed by the following equations 1-2. In equations (1) and (2), j is a complex number and ω [rad / sec] is the angular velocity.

[0107]

[0108]

[0109] Current imbalance occurs due to an imbalance between the impedance of the first winding Z21 and the impedance of the second winding Z22. From Equation 1-2, it can be seen that in order to suppress the imbalance between the impedance of the first winding Z21 and the impedance of the second winding Z22, it is desirable that the resistance of the first winding R21 and the resistance of the second winding R22 match, and that the inductance of the first winding L21 and the inductance of the second winding L22 match.

[0110] If the material, diameter, and circumference of the wires constituting the winding 20 are the same, the first winding resistance R21 and the second winding resistance R22 will generally coincide. On the other hand, as will be described later, the flux linkage changes depending on the positional relationship inside the slots 13 of the winding 20, so the first winding inductance L21 and the second winding inductance L22 are not necessarily the same. Therefore, the motor 1 according to this embodiment 1 aims to approximate the values ​​of the first winding inductance L21 and the second winding inductance L22.

[0111] The relationship between the first winding inductance L21 and the second winding inductance L22 in the motor 1 according to this embodiment 1 will be explained. Figure 34 shows data representing the inductance ratio (L1 / L2) of the first winding 21 and the second winding 22 in the motor 1a according to comparative example 1 and the motor 1 according to this embodiment 1. The closer the inductance ratio (L1 / L2) approaches 100%, the closer the values ​​of the first winding inductance L21 and the second winding inductance L22 become.

[0112] As shown in Figure 34, the inductance ratio of the motor 1a according to Comparative Example 1 is 104.6%, while the inductance ratio of the motor 1 according to Embodiment 1 is 100.9%. In other words, the values ​​of the first winding impedance Z21 and the second winding impedance Z22 can be made closer in the motor 1 according to Embodiment 1 compared to the motor 1a according to Comparative Example 1.

[0113] The reason why the inductance ratio (L1 / L2) of the motor 1 according to this embodiment 1 approaches 100% compared to the motor 1a according to comparative example 1 will be explained. Figure 35 is a schematic diagram showing the magnetic flux flowing around the winding 20 when the winding 20 is located on the outer diameter side of the slot 13. Figure 36 is a schematic diagram showing the magnetic flux flowing around the winding 20 when the winding 20 is located on the inner diameter side of the slot 13.

[0114] As shown in Figure 35, magnetic flux flows in a circular motion along the outer circumference of the winding 20, and the inductance of the winding 20 is determined based on this amount of magnetic flux. When the winding 20 is located on the outer diameter side of the slot 13, a closed-loop magnetic path is formed in which the magnetic flux passes from tooth 12 towards back yoke 11, from back yoke 11 towards the next tooth 12, from the next tooth 12 through the slot 13, and back to tooth 12.

[0115] As shown in Figure 36, when the winding 20 is located on the inner diameter side of the slot 13, a closed-loop magnetic path is formed in which the magnetic flux flows from tooth 12 through the slot 13 to the adjacent tooth 12, flows toward the inner diameter side of tooth 12, and returns to tooth 12.

[0116] In other words, even within the same slot 13, the inductance tends to be larger near the winding 20 located on the outer diameter side of the slot 13 because there is less air in the magnetic path near the winding 20. On the other hand, the inductance tends to be smaller near the winding 20 located on the inner diameter side of the slot 13 because there is more air in the magnetic path compared to the winding 20 located on the outer diameter side of the slot 13.

[0117] As a result, by connecting the winding 20 located on the outer diameter side of the slot 13 and the winding 20 located on the inner diameter side of the slot 13 in parallel, the difference in inductance causes an imbalance in the current flowing through each winding 20. This results in a current with a large amplitude flowing through the winding 20 located on the inner diameter side of the slot 13, and a current with a small amplitude flowing through the winding 20 located on the outer diameter side of the slot 13.

[0118] Based on the above, in the motor 1a according to Comparative Example 1, when comparing the first winding 31, in which the first outer layer winding 31a, the second outer layer winding 31b, and the third outer layer winding 31c are connected in series, with the second winding 32, in which the first inner layer winding 32a, the second inner layer winding 32b, and the third inner layer winding 32c are connected in series, the relationship between the current Iu31 flowing through the first winding 31 and the current Iu32 flowing through the second winding 32 is Iu31 < Iu32.

[0119] As shown in Figures 27 and 29, in the motor 1b according to Comparative Example 2, since the first winding 41 and the second winding 42 are connected in series, an imbalance in current does not occur even if there is an imbalance in the inductance between the first winding 41 and the second winding 42, and therefore, there is no increase in internal copper loss. However, compared to the motor 1 according to Embodiment 1, where the first winding 21 and the second winding 22 are connected in parallel, connecting the first winding 41 and the second winding 42 in series as in the motor 1b according to Comparative Example 2 halves the number of turns in one winding 20. As a result, the cross-sectional area of ​​each wire constituting the winding 20 doubles, resulting in thicker wires. This thicker wire may make it more difficult to bend the wires when winding the winding 20 around the stator core 10, or increase the cycle time in the winding process.

[0120] In the motor 1 according to this embodiment 1, even though the first winding 21 and the second winding 22 are connected in parallel, the amplitude and phase of the current Iu21 flowing through the first winding 21 and the current Iu22 flowing through the second winding 22 can be matched, as shown in Figure 30. In other words, the motor 1 according to this embodiment 1 can improve motor efficiency by reducing copper loss in the windings and suppress deterioration in the productivity of the windings 20.

[0121] As described above, the stator 2 according to this embodiment 1 comprises a stator core 10 constructed by stacking electromagnetic steel sheets in the axial direction, and a winding 20 wound around the stator core 10 in a distributed winding. The stator core 10 has a plurality of slots 13 in the circumferential direction, and the winding 20 has a first winding 21 and a second winding 22. The first winding 21 has a first outer layer winding 21a and a first inner and outer layer winding 21b connected in series, and the second winding 22 has a first inner layer winding 22a and a second inner and outer layer winding 22b connected in series. In a plane perpendicular to the axial direction, when the first circle C11 is defined as the circle centered on the axis C1 of the stator core 10 and passing through the outermost diameter portion of the slot 13 in the radial direction, the second circle C12 is defined as the circle centered on the axis C1 of the stator core 10 and passing through the innermost diameter portion of the stator core 10 in the radial direction, and the third circle C13 is defined as the circle that bisects the first circle C11 and the second circle C12 in the radial direction with respect to the axis C1 of the stator core 10, the first outer layer winding 21a is arranged across two slots 13, and the radial center of the first outer layer winding 21a in one slot 13 and the other slot 13 is located on the outer diameter side of the third circle C13. The first inner and outer layer winding 21b is arranged across two slots 13, with the radial center of the first inner and outer layer winding 21b located on the outer side of the third circle C13 in one slot 13, and the radial center of the first inner and outer layer winding 21b located on the inner side of the third circle C13 in the other slot 13. The first inner layer winding 22a is arranged across two slots 13, with the radial center of the first inner layer winding 22a located on the inner side of the third circle C13 in both slots 13 and the other slot 13. The second inner and outer layer winding 22b is arranged across two slots 13, with the radial center of the second inner and outer layer winding 22b located on the outer side of the third circle C13 in one slot 13, and the radial center of the second inner and outer layer winding 22b located on the inner side of the third circle C13 in the other slot 13.

[0122] This feature allows the motor 1 according to this embodiment 1 to suppress imbalance in the inductance of the windings 20 even when the single-phase windings 20 are connected in parallel. As a result, the current is distributed uniformly through the parallel connection, reducing copper losses in the windings 20. Therefore, it has the effect of improving motor efficiency.

[0123] Furthermore, the motor 1 according to this embodiment 1 can increase the number of turns in a single winding 20 by connecting the single-phase windings 20 in parallel, compared to the case where the single-phase windings 20 are connected in series. In other words, the cross-sectional area of ​​each wire constituting the winding 20 can be reduced. As a result, since the wires can be made thinner, it is possible to bend the wires when winding the windings 20 around the stator core 10, thereby suppressing the deterioration of the productivity of the windings 20.

[0124] Furthermore, the stator of Embodiment 1 configured as described above comprises: a stator core formed by stacking electromagnetic steel sheets in the axial direction; and windings wound around the stator core in a distributed winding manner, wherein the stator core has a plurality of slots in the circumferential direction; the windings have a first winding and a second winding; the first winding and the second winding are connected in parallel; the first winding has a first outer layer winding and a first inner and outer layer winding connected in series; and the second winding has a first inner layer winding and a second inner and outer layer winding connected in series. In a plane perpendicular to the axial direction, when a circle passing through the outermost diameter portion of the slot in the radial direction with respect to the rotation axis of the stator core is defined as the first circle, a circle passing through the innermost diameter portion of the stator core in the radial direction with respect to the rotation axis of the stator core is defined as the second circle, and a circle bisecting the first circle and the second circle in the radial direction with respect to the rotation axis of the stator core is defined as the third circle, the first outer layer winding is arranged across two slots, and in one slot and the other slot, either the radial center or the center of gravity of the first outer layer winding is located on the outer diameter side of the third circle, the first inner and outer layer winding is arranged across two slots, and in one slot, either the radial center or the center of gravity of the first inner and outer layer winding is located on the outer diameter side of the third circle, and in the other slot, either the radial center or the center of gravity of the first inner and outer layer winding is located on the inner diameter side of the third circle, In a stator, the first inner layer winding is arranged across two slots, with either the radial center or the centroid of the first inner layer winding located inward from the third circle in one slot and the other slot, and the second inner and outer layer winding is arranged across two slots, with either the radial center or the centroid of the second inner and outer layer winding located outward from the third circle in one slot and either the radial center or the centroid of the second inner and outer layer winding located inward from the third circle in the other slot, the winding is formed in multiple phases, only windings of the same phase are arranged in one slot, the first inner layer windings of each phase are arranged at different positions in the circumferential direction, and the first inner layer windings of each phase are formed such that no first inner layer windings of other phases are arranged between the slots where the first inner layer windings of one phase are arranged.In a stator using distributed windings, the windings of each phase are arranged so that their density is dispersed, thereby providing a stator that reduces the load on winding insertion and improves the insertion of the wedge, which is an insulating paper.

[0125] Furthermore, the motor of Embodiment 1 configured as described above further comprises: the first winding further having a third inner and outer layer winding connected in series with the first inner and outer layer winding; the second winding further having a fourth inner and outer layer winding connected in series with the second inner and outer layer winding; the third inner and outer layer winding is arranged across two slots, with either the radial center or the center of gravity of the third inner and outer layer winding located on the outer diameter side of the third circle in one slot, and either the radial center or the center of gravity of the third inner and outer layer winding located on the inner diameter side of the third circle in the other slot; the fourth inner and outer layer winding is arranged across two slots, with either the radial center or the center of gravity of the fourth inner and outer layer winding located on the outer diameter side of the third circle in one slot, and either the radial center or the center of gravity of the fourth inner and outer layer winding located on the inner diameter side of the third circle in the other slot; To explain in more detail, in the structure shown in Comparative Example 1 in Figure 24, that is, in the parallel connection of the first winding 31 in which each winding 31a, 31b, and 31c are arranged radially outward from the third circle C13, and the second winding 32 in which each winding 32a, 32b, and 32c are arranged radially inward from the third circle C13, there was a problem with the current imbalance state, as shown in Figure 28 of Comparative Example 1, where there was a significant difference between the waveform of the current Iu31 flowing through the first winding 31 and the waveform of the current Iu32 flowing through the second winding 32. By adopting the winding configuration of the motor in Embodiment 1 shown in Figure 3, even though the winding 20 in Embodiment 1 is connected in parallel, similar to the winding 20a in Comparative Example 1, the motor 1 in Embodiment 1 can suppress the current imbalance state between the first winding 21 and the second winding 22 compared to the motor 1a in Comparative Example 1. As a result, the performance of the motor can be improved and productivity can be increased.

[0126] Furthermore, in the stator of Embodiment 1 configured as described above, the first winding and the second winding are connected to the neutral point, so the path of circulating current is interrupted, and thus the efficiency of the motor can be increased.

[0127] Furthermore, in the stator of Embodiment 1 configured as described above, the winding has three phases and is configured in a Y-connection, so the path of circulating current is reliably interrupted, preventing the generation of circulating current and thus reliably increasing the efficiency of the motor.

[0128] Furthermore, in the stator of Embodiment 1 configured as described above, the winding has a coil end that extends radially to the outside of the axial end face of the stator core, and there is a gap between the axial end face of the stator core and the coil end. Therefore, it is possible to insert equipment for forming the winding into the gap, thereby improving the productivity of winding.

[0129] Furthermore, the electric motor of Embodiment 1 configured as described above is an electric motor comprising the stator and rotor described above, wherein the rotor has permanent magnets and a rotor core, the rotor core is constructed by laminating electromagnetic steel sheets in the axial direction and has magnet insertion holes, one or more magnet insertion holes are provided for each magnetic pole, and the permanent magnets are inserted to form magnetic poles of number P, thereby improving the performance of the electric motor and improving productivity.

[0130] Embodiment 2. Regarding Embodiment 2, the parts that are the same as those in Embodiment 1 will be omitted from the explanation as appropriate, and the explanation will focus on the differences from Embodiment 1. Note that the <Motor Configuration>, <Rotor Configuration>, and <Stator Configuration> are the same as in Embodiment 1, so their explanations will be omitted.

[0131] <Winding Configuration> The configuration of the winding 20c in the stator 2c according to this second embodiment will be described. The winding 20c of the stator 2c according to this second embodiment is a three-phase system consisting of U-phase, V-phase, and W-phase, but only the U-phase is shown in Figure 43 for explanatory purposes. Note that the V-phase and W-phase are formed in the same way as the U-phase, so their explanation will be omitted as appropriate.

[0132] Figure 44 is a circuit diagram of the winding 20c according to this second embodiment. As shown in Figure 44, the winding 20c according to this second embodiment has the first winding 151 and the second winding 152 connected in parallel.

[0133] As shown in Figures 43 and 44, the first winding 151 consists of a winding housed on the outer diameter side of the slot 13 (hereinafter referred to as "first outer layer winding 151a"), a winding housed on the inner diameter side of the slot 13 (hereinafter referred to as "first inner / outer layer winding 151b"), and a winding housed on the inner diameter side of the slot 13 (hereinafter referred to as "second inner layer winding 151c"), all connected in series. The first outer layer winding 151a, the first inner / outer layer winding 151b, and the second inner layer winding 151c are each bundles of multiple wires.

[0134] As shown in Figure 43, the first outer layer winding 151a, the first inner and outer layer winding 151b, and the second inner layer winding 151c are each wound at a 3-slot pitch, or in other words, every 3 slots. Slot pitch refers to the circumferential angle between adjacent slots. In the stator 2c according to this second embodiment, 18 slots 13 are formed at equal intervals in the stator core 10, so the slot pitch is 360 degrees / 18 = 20 degrees in mechanical angle.

[0135] In other words, the same first outer layer winding 151a is inserted into the third slot from the slot 13 into which the first outer layer winding 151a is inserted. To put it another way, the first outer layer winding 151a, the first inner and outer layer winding 151b, and the second inner layer winding 151c are wound so as to span three teeth 12.

[0136] Since the winding 20c is wound with a 3-slot pitch, each individual winding 20c is wound over a mechanical angle of 360 degrees × 3 / 18 = 60 degrees. In other words, the coil pitch is 60 degrees mechanically.

[0137] Furthermore, the first outer layer winding 151a, the first inner and outer layer winding 151b, and the second inner layer winding 151c are each arranged at intervals of 3 slot pitches.

[0138] The second winding 152 consists of a winding housed on the inner diameter side of the slot 13 (hereinafter referred to as "first inner layer winding 152a"), windings arranged every three slot pitches from the first inner layer winding 152a and housed on the inner diameter side of the slot 13 and on the outer diameter side of the slot 13 (hereinafter referred to as "second inner / outer layer winding 152b"), and windings arranged every three slot pitches from the second inner / outer layer winding 152b and housed on the outer diameter side of the slot 13 (hereinafter referred to as "second outer layer winding 152c"), all connected in series. The first inner layer winding 152a, the second inner / outer layer winding 152b, and the second outer layer winding 152c are each bundles of multiple wires.

[0139] As shown in Figure 43, in the stator core 10 according to this second embodiment, a first circle C11, a second circle C12, and a third circle C13 are defined. Specifically, similar to the first embodiment described above, in a plane perpendicular to the axial direction, the first circle C11 is a virtual circle centered on the axis C1 of the stator core 10 and passing through the outermost diameter portion of the slot 13 in the radial direction. The second circle C12 is a virtual circle centered on the axis C1 of the stator core 10 and passing through the innermost diameter portion of the stator core 10 in the radial direction. The third circle C13 is a virtual circle that bisects the first circle C11 and the second circle C12 in the radial direction, centered on the axis C1 of the stator core 10.

[0140] The first outer layer winding 151a provided on the first winding 151 will now be described. As shown in Figure 43, the first outer layer winding 151a is arranged across two slots 13. In one slot 13 and the other slot 13, either the radial center or the centroid of the first outer layer winding 151a is located on the outer diameter side of the third circle C13.

[0141] The first inner and outer layer windings 151b provided on the first winding 151 will now be described. As shown in Figure 43, the first inner and outer layer windings 151b are arranged across two slots 13, with either the radial center or the centroid of the first inner and outer layer windings 151b located on the outer diameter side of the third circle C13 in one slot 13, and either the radial center or the centroid of the first inner and outer layer windings 151b located on the inner diameter side of the third circle C13 in the other slot 13.

[0142] The second inner layer winding 151c provided on the first winding 151 will now be described. As shown in Figure 43, the second inner layer winding 151c is arranged across two slots 13, with either the radial center or the centroid of the second inner layer winding 151c located on the inner side of the third circle C13 in one slot 13, and either the radial center or the centroid of the second inner layer winding 151c located on the inner side of the third circle C13 in the other slot 13.

[0143] The first inner layer winding 152a provided in the second winding 152 will now be described. As shown in Figure 43, the first inner layer winding 152a is arranged across two slots 13, and in one slot 13 and the other slot 13, either the radial center or the centroid of the first inner layer winding 22a is located on the inner diameter side of the third circle C13.

[0144] The second inner and outer layer winding 152b provided on the second winding 152 will now be described. As shown in Figure 43, the second inner and outer layer winding 152b is arranged across two slots 13, with either the radial center or the centroid of the second inner and outer layer winding 152b located on the outer diameter side of the third circle C13 in one slot 13, and either the radial center or the centroid of the second inner and outer layer winding 152b located on the inner diameter side of the third circle C13 in the other slot 13.

[0145] The second outer layer winding 152c provided on the second winding 152 will now be described. As shown in Figure 43, the second outer layer winding 152c is arranged across two slots 13, with either the radial center or the centroid of the second outer layer winding 152c located on the outer diameter side of the third circle C13 in one slot 13, and either the radial center or the centroid of the second outer layer winding 152c located on the outer diameter side of the third circle C13 in the other slot 13.

[0146] In other words, the stator 2c according to this second embodiment is provided with six windings 20c per phase.

[0147] <Production Method of Windings> The production method of windings 20c according to this second embodiment will be explained, focusing on the differences from the first embodiment described above. Figure 45 is a top view showing windings 20c according to this second embodiment inserted into an inserter 200. An inserter 200 as shown in Figure 45 is used to insert windings 20c into slots 13.

[0148] As shown in Figure 45, the first outer layer winding 151a, the first inner and outer layer winding 151b, the second inner layer winding 151c, the first inner layer winding 152a, the second inner and outer layer winding 152b, and the second outer layer winding 152c are mounted on the inserter 200. The inserter 200 is fitted in the following order: either the second inner layer winding 151c or the first inner layer winding 152a, the other of either the second inner layer winding 151c or the first inner layer winding 152a, either the first inner / outer layer winding 151b or the second inner / outer layer winding 152b, the other of either the first inner / outer layer winding 151b or the second inner / outer layer winding 152b, either the first outer layer winding 151a or the second inner layer winding 151c, and the other of either the first outer layer winding 151a or the second inner layer winding 151c. In other words, after being mounted on the inserter 200, the second inner layer winding 151c, the first inner and outer layer winding 151b, and the first outer layer winding 151a are arranged in a stepped manner, as shown in Figure 45, and the first inner layer winding 152a, the second inner and outer layer winding 152b, and the second outer layer winding 152c are also arranged in a stepped manner. Each winding 20c is stretched across the three blades 201. Note that Figure 45 shows an example of the case shown in Figure 43.

[0149] The inserter 200 is inserted into the inner diameter side of the stator core 10 so that each blade 201 faces the radially inward side of the teeth 12, and is then withdrawn axially. As a result, each winding stretched across the blade 201 is housed in the slot 13 in the order of first outer layer winding 151a and second inner layer winding 151c, first inner and outer layer winding 151b and second inner and outer layer winding 152b, second inner layer winding 151c and first inner layer winding 152a, and wound around the stator core 10.

[0150] <Effects of the motor according to this embodiment 2> The effects of the motor according to this embodiment 2 will be explained. For comparison, in this embodiment 1, each winding stretched across the blade 201 in Figure 22 is housed in the slot 13 in the order of the first outer layer winding 21a, the first inner and outer layer winding 21b, the third inner and outer layer winding 21c, the fourth inner and outer layer winding 22c, the second inner and outer layer winding 22b, and the first inner layer winding 22a. Therefore, the insertion force generated by the drive source of the equipment that inserts the windings is transmitted from the blade 201 in the order of the first outer layer winding 21a, the first inner and outer layer winding 21b, the third inner and outer layer winding 21c, the fourth inner and outer layer winding 22c, the second inner and outer layer winding 22b, and the first inner layer winding 22a. In other words, each winding 20 transmits the insertion force to each other.

[0151] On the other hand, in this second embodiment, the windings stretched across the blade 201 in Figure 45 are housed in the slot 13 in the following order: first outer layer winding 151a and second outer layer winding 152c, first inner / outer layer winding 151b and second inner / outer layer winding 152b, second inner layer winding 151c and first inner layer winding 152a. Therefore, the insertion force generated by the drive source of the winding insertion equipment is transmitted from the blade 201 in the following order: first outer layer winding 151a and second outer layer winding 152c, first inner / outer layer winding 151b and second inner / outer layer winding 152b, second inner layer winding 151c and first inner layer winding 152a. In other words, compared to the first embodiment, in this second embodiment, there are fewer points where the windings 20c transmit insertion force to each other, and there are more points where the blade 201 directly pushes up the windings 20c. Therefore, compared to Embodiment 1, Embodiment 2 improves the insertability of the windings, making it possible to suppress insertion defects in the winding insertion process, such as defects caused by insufficient insertion of the winding 20c, and thereby improving productivity.

[0152] As described above, the stator 2c according to this second embodiment comprises a stator core 10 constructed by stacking electromagnetic steel sheets in the axial direction, and a winding 20c wound around the stator core 10 in a distributed winding. The stator core 10 has a plurality of slots 13 in the circumferential direction, and the winding 20c has a first winding 151 and a second winding 152. The first winding 151 has a first outer layer winding 151a and a first inner / outer layer winding 151b connected in series, and the second winding 152 has a first inner layer winding 152a and a second inner / outer layer winding 152b connected in series. In a plane perpendicular to the axial direction, when the first circle C11 is defined as the circle that passes through the outermost diameter portion of the slot 13 in the radial direction with the axis C1 of the stator core 10 as the center, the second circle C12 is defined as the circle that passes through the innermost diameter portion of the stator core 10 in the radial direction with the axis C1 of the stator core 10 as the center, and the third circle C13 is defined as the circle that bisects the first circle C11 and the second circle C12 in the radial direction with the axis C1 of the stator core 10 as the center, the first outer layer winding 151a is arranged across two slots 13, and the radial center of the first outer layer winding 151a in one slot 13 and the other slot 13 is located on the outer diameter side of the third circle C13. The first inner and outer layer winding 151b is arranged across two slots 13, with the radial center of the first inner and outer layer winding 151b located on the outer side of the third circle C13 in one slot 13, and the radial center of the first inner and outer layer winding 151b located on the inner side of the third circle C13 in the other slot 13. The first inner layer winding 152a is arranged across two slots 13, with the radial center of the first inner layer winding 152a located on the inner side of the third circle C13 in both slots 13 and the other slot 13. The second inner and outer layer winding 152b is arranged across two slots 13, with the radial center of the second inner and outer layer winding 152b located on the outer side of the third circle C13 in one slot 13, and the radial center of the second inner and outer layer winding 152b located on the inner side of the third circle C13 in the other slot 13.

[0153] This feature allows the motor according to this second embodiment to suppress imbalance in the inductance of the windings 20c even when the single-phase windings 20c are connected in parallel. As a result, the current is distributed uniformly through the parallel connection, reducing copper losses in the windings 20c. This has the effect of improving motor efficiency.

[0154] Furthermore, in the motor according to this second embodiment, by connecting the one-phase windings 20c in parallel, the number of turns in a single winding 20c can be increased compared to when the one-phase windings 20c are connected in series. In other words, the cross-sectional area of ​​each wire constituting the winding 20c can be reduced. As a result, since the wires can be made thinner, it is possible to make it easier to bend the wires when winding the windings 20c around the stator core 10, thereby suppressing the deterioration of the productivity of the windings 20c. In addition, the insertion force generated by the drive source of the winding insertion equipment causes the blade 201 to directly push up the windings 20c in many places. Therefore, the insertability of the windings is improved, and it is possible to suppress insertion defects in the winding insertion process, such as defects due to insufficient insertion of the windings 20c, thereby improving productivity.

[0155] Furthermore, the stator of Embodiment 2 configured as described above provides the same effects as Embodiment 1, and the first winding further comprises a second inner winding connected in series with the first inner and outer layer windings, the second winding further comprises a second outer winding connected in series with the second inner and outer layer windings, the second inner winding is arranged across two slots, with either the radial center or the centroid of the second inner winding located inward from the third circle in one slot and the other slot, and the second outer winding is arranged across two slots, with either the radial center or the centroid of the second outer winding located outward from the third circle in one slot and the other slot. Therefore, the motor according to Embodiment 2 can not only suppress the current imbalance between the first winding 151 and the second winding 152, but also improve the insertability of the winding 20c. As a result, the performance of the motor can be improved and productivity can be increased.

[0156] Embodiment 3. <Compressor Configuration and Operation> The compressor 60 according to Embodiment 3 will now be described. Figure 37 is a cross-sectional view showing an example of the compressor 60 according to Embodiment 3. The compressor 60 is, for example, a rotary compressor. Note that the compressor 60 is not limited to a rotary compressor, but may be other compressors 60 such as a low-pressure compressor or a scroll compressor.

[0157] As shown in Figure 37, the compressor 60 includes the electric motor 1 described in Embodiment 1, a crankshaft 65 as a rotating shaft, a compression mechanism 70, and a sealed container 90. The electric motor 1 drives the compression mechanism 70. The compression mechanism 70 compresses a refrigerant (not shown) drawn in from the accumulator 100. The configuration of the compression mechanism 70 will be described later.

[0158] The crankshaft 65 connects the electric motor 1 and the compression mechanism 70. The crankshaft 65 has a shaft body portion 65a fixed to the rotor 3 of the electric motor 1 and an eccentric shaft portion 65b fixed to the rolling piston 80 of the compression mechanism 70.

[0159] The sealed container 90 is cylindrical and houses the electric motor 1 and the compression mechanism 70. Refrigerant oil (not shown) is stored in an oil reservoir at the bottom of the sealed container 90. The refrigerant oil is a lubricant that lubricates the sliding parts of the compression mechanism 70 (for example, the fitting portion between the rolling piston 80 and the eccentric shaft 65b). The refrigerant oil lubricates the sliding parts of the compression mechanism 70 through an oil supply passage formed inside the crankshaft 65.

[0160] The compressor 60 further includes a discharge pipe 91 and a terminal 92 attached to the top of the sealed container 90. The discharge pipe 91 discharges the refrigerant compressed by the compression mechanism 70 to the outside of the sealed container 90. The discharge pipe 91 is connected to the refrigerant circuit shown in Figure 40 or 41, which will be described later in Embodiment 4 below.

[0161] Terminal 92 is connected to a drive device (not shown) located outside the compressor 60. Terminal 92 also supplies motor current Ia to the windings 20 of the stator 2 of the electric motor 1 via lead wire 93. This causes the rotor 3 of the electric motor 1 to rotate.

[0162] Figure 38 is a cross-sectional view showing the configuration of the compression mechanism 70 according to this third embodiment. As shown in Figure 38, the compression mechanism 70 includes a cylinder 71, a rolling piston 80, a vane 81, an upper bearing portion 82, and a lower bearing portion 84. The cylinder 71 has an intake port 71a, a cylinder chamber 71b, and a vane groove 71c. The intake port 71a is connected to the accumulator 100 via an intake pipe 72. The intake port 71a is a passage through which the refrigerant drawn in from the accumulator 100 flows, and is in communication with the cylinder chamber 71b.

[0163] In the following explanation, the direction along the circumference of the circle centered on the crankshaft 65 is referred to as the "circumferential direction," the direction of the axis C1, which is the rotation center of the crankshaft 65, is referred to as the "axial direction," and the direction of the straight line passing through the crankshaft 65 perpendicular to the axial direction is referred to as the "radial direction." In addition, the drawings show an xyz Cartesian coordinate system to facilitate understanding between the drawings. The z-axis is a coordinate axis parallel to the axis C1 of the crankshaft 65. The y-axis is a coordinate axis perpendicular to the z-axis. The x-axis is a coordinate axis perpendicular to both the y-axis and the z-axis.

[0164] The cylinder chamber 71b is a cylindrical space centered on axis C1. The cylinder chamber 71b houses the eccentric shaft portion 65b of the crankshaft 65, the rolling piston 80, and the vanes 81. When viewed in the z-axis direction, the rolling piston 80 has a ring shape. The rolling piston 80 is fixed to the eccentric shaft portion 65b of the crankshaft 65.

[0165] The vane groove 71c is in communication with the cylinder chamber 71b. A vane 81 is mounted in the vane groove 71c. A back pressure chamber 71d is formed at the end of the vane groove 71c. The vane 81 is pressed toward the axis C1 by a spring (not shown) located in the back pressure chamber 71d, and contacts the outer circumferential surface of the rolling piston 80. As a result, the vane 81 divides the space enclosed by the inner circumferential surface of the cylinder chamber 71b, the outer circumferential surface of the rolling piston 80, the upper bearing portion 82, and the lower bearing portion 84 into an intake-side working chamber (hereinafter referred to as the "intake chamber 86a") and a compression-side working chamber (hereinafter referred to as the "compression chamber 86b"). The intake chamber 86a is in communication with the intake port 71a.

[0166] The vane 81 reciprocates in the y-axis direction within the vane groove 71c when the rolling piston 80 is rotating eccentrically. The vane 81 is, for example, plate-shaped. In the example shown in Figure 38, the rolling piston 80 and the vane 81 are separate components, but the rolling piston 80 and the vane 81 may be integrated.

[0167] As shown in Figure 37, the upper bearing portion 82 closes the +z-axis end of the cylinder chamber 71b. The lower bearing portion 84 closes the -z-axis end of the cylinder chamber 71b. The upper bearing portion 82 and the lower bearing portion 84 are each fixed to the cylinder 71 by fastening members (not shown), such as bolts.

[0168] The upper bearing section 82 and the lower bearing section 84 each have a discharge port for discharging compressed refrigerant to the outside of the cylinder chamber 71b. The discharge ports of the upper bearing section 82 and the lower bearing section 84 are in communication with the compression chamber 86b of the cylinder chamber 71b. The discharge ports are equipped with discharge valves (not shown). The discharge valves open when the pressure of the refrigerant compressed in the compression chamber exceeds a predetermined pressure, discharging the high-temperature, high-pressure refrigerant into the internal space of the sealed container 90. The lower bearing section 84 does not necessarily have to be equipped with a discharge port.

[0169] An upper discharge muffler 83 is attached to the upper bearing portion 82 by fastening members (for example, bolts). A muffler chamber 83a is provided between the upper bearing portion 82 and the upper discharge muffler 83. As a result, the refrigerant discharged from the discharge port of the upper bearing portion 82 diffuses into the muffler chamber 83a, thereby suppressing the generation of discharge noise from the refrigerant discharged from the discharge port of the upper bearing portion 82.

[0170] Furthermore, a lower discharge muffler 85 is attached to the lower bearing portion 84 by fastening members (for example, bolts). A muffler chamber 85a is provided between the lower bearing portion 84 and the lower discharge muffler 85. As a result, the refrigerant discharged from the discharge port of the lower bearing portion 84 diffuses into the muffler chamber 85a, thereby suppressing the generation of discharge noise from the refrigerant discharged from the lower bearing portion 84. Note that if a discharge port is formed in either the upper bearing portion 82 or the lower bearing portion 84, the discharge muffler may be provided on the frame in which the discharge port is formed.

[0171] In the compressor 60 according to this third embodiment, the electric motor 1 described in the first embodiment is used, so the same advantages as those described in the first embodiment can be obtained. As a result, a highly efficient compressor 60 can be provided.

[0172] Embodiment 4. The air conditioning system 250 according to Embodiment 4 will be described in detail below with reference to the drawings.

[0173] <Configuration and Operation of the Air Conditioning System> Figure 39 is a schematic diagram showing the configuration of the air conditioning system 250 according to this embodiment 4. The air conditioning system 250 of this embodiment 4 consists of an outdoor unit 260, an indoor unit 270, and refrigerant piping 280.

[0174] Figures 40 and 41 are refrigerant circuit diagrams showing the flow of refrigerant in the air conditioning system 250 according to this fourth embodiment. Figure 40 shows the cooling operation, and Figure 41 shows the heating operation.

[0175] The outdoor unit 260 consists of an outdoor heat exchanger 261, an outdoor blower 262, a compressor 60 according to embodiment 3, a four-way valve 263, and an expansion valve 264.

[0176] The indoor unit 270 consists of an indoor heat exchanger 271 and an indoor blower 272.

[0177] The outdoor heat exchanger 261 functions as a condenser during cooling operation and as an evaporator during heating operation. Similarly, the indoor heat exchanger 271 functions as an evaporator during cooling operation and as a condenser during heating operation. Switching between cooling and heating operation is performed by switching the flow path using a four-way valve 263.

[0178] The compressor 60 compresses the refrigerant it inhales and then discharges it.

[0179] The four-way valve 263 changes the direction of flow of the refrigerant in the refrigerant circuit. The expansion valve 264 depressurizes the refrigerant and causes it to expand.

[0180] Let's explain the operation of the condenser. The air conditioning system 250 sends high-temperature, high-pressure refrigerant gas from the compressor 60 to the condenser, where it exchanges heat with a medium (for example, air) to condense the refrigerant gas and send it out as low-temperature, high-pressure liquid refrigerant. Heat exchange with the medium occurs when the refrigerant flows into the condenser and the medium passes between two fins in a direction perpendicular to the axis of the heat transfer tube. As a result, heat equivalent to the amount of heat lost from the refrigerant due to condensation is released to the outside of the condenser.

[0181] During cooling operation, heat is released from the outdoor heat exchanger 261, which functions as a condenser, and the warm air is released to the outside of the outdoor unit 260 by the outdoor fan 262. During heating operation, heat is released from the indoor heat exchanger 271, which functions as a condenser, and the warm air is supplied to the room by the indoor fan 272.

[0182] Let's explain the operation of the evaporator. The low-temperature gas-liquid mixed refrigerant, sent out from the expansion valve 264, flows into the evaporator and evaporates through heat exchange with a medium (for example, air), releasing it as a low-temperature refrigerant gas. Heat exchange with the medium occurs when the refrigerant flows into the evaporator and the medium passes between two fins in a direction perpendicular to the axis of the heat transfer tube. As a result, the area outside the evaporator is cooled by the amount of heat increased by the refrigerant due to evaporation.

[0183] During heating operation, the outdoor heat exchanger 261, which functions as an evaporator, cools the air, and the outdoor fan 262 releases the cool air to the outside of the outdoor unit 260. During cooling operation, the indoor heat exchanger 271, which functions as an evaporator, cools the air, and the indoor fan 272 supplies the cool air to the room.

[0184] The refrigerant is a mixed refrigerant containing ethylene-based fluorinated hydrocarbons having carbon double bonds. By using a mixed refrigerant containing ethylene-based fluorinated hydrocarbons having carbon double bonds, the operating pressure of the compressor 60 is reduced, and the disproportionation reaction of the refrigerant can be prevented. In this embodiment 4, the refrigerant is a mixed refrigerant containing R1123. Note that the refrigerant is not limited to R1123, but may be a mixed refrigerant containing other ethylene-based fluorinated hydrocarbons.

[0185] The refrigerant only needs to contain one or more types of ethylene-based fluorinated hydrocarbons, and is a mixed refrigerant obtained by mixing ethylene-based fluorinated hydrocarbons with other refrigerants. For example, the refrigerant is a mixed refrigerant of R1123 and R32. It is desirable that the proportion of R1123 in this mixed refrigerant be set within the range of 40 wt% to 60 wt%. By setting the proportion of R1123 within the range of 40 wt% to 60 wt%, it is possible to construct a refrigerant with high refrigerant performance while having a low global warming potential (GWP). Note that R1123 is not limited to R32, but may be mixed with one or more of the following refrigerants: R1234yf, R1234ze(E), R1234ze(Z), R125, and R134a.

[0186] Furthermore, the refrigerant may also be a refrigerant having two or more types of ethylene-based fluorinated hydrocarbons. For example, R1123 may be mixed with one or more of the ethylene-based fluorinated hydrocarbons R1141, R1132a, R1132(E), and R1132(Z). In addition, the refrigerant may be a mixture of R516A, R445A, R444A, R454C, R444B, R454A, R455A, R457A, R459B, R452B, R454B, R447B, R447A, R446A, and R459A.

[0187] Furthermore, the refrigerant may be a single refrigerant such as R1234yf, R1234ze, R32, or R290.

[0188] In the air conditioning system 250 according to this fourth embodiment, the electric motor 1 described in the first embodiment is used for the compressor 60, so the same advantages as those described in the first embodiment can be obtained. As a result, a highly efficient air conditioning system 250 can be provided.

[0189] The electric motor 1 described in Embodiment 1 can be mounted on any electrical equipment that has a drive source, such as machine tools, electric vehicles, drones, and robots.

[0190] While this disclosure describes various exemplary embodiments and examples, the various features, aspects, and functions described in one or more embodiments are not limited to the application of a particular embodiment, but are applicable individually or in various combinations to the embodiments. Accordingly, countless variations not illustrated are envisioned within the scope of the art disclosed in this specification. For example, these include modifying, adding or omitting at least one component, and further, extracting at least one component and combining it with a component from another embodiment.

[0191] 1. Electric motor, 151. First winding, 151a. First outer layer winding, 151b. First inner and outer layer winding, 151c. Second inner layer winding, 152. Second winding, 152a. First inner layer winding, 152b. Second inner and outer layer winding, 152c. Second outer layer winding, 2. Stator, 2c. Stator, 3. Rotor, 10. Stator core, 13. Slot, 20. Winding, 20c. Winding, 21. First winding, 21a. First outer layer winding, 21b. First inner and outer layer winding, 21c. Third inner and outer layer winding, 22. Second winding, 22a. First inner layer winding, 22b. Second inner and outer layer winding, 22c. Fourth inner and outer layer winding, 50. Rotor core, 51. Magnet insertion hole, 58. Permanent magnet, 60. Compressor, 70. Compression mechanism section, 211 coil end, 213 gap section, 250 air conditioning device, C1 axis, C11 first circle, C12 second circle, C13 third circle, N neutral point.

Claims

1. A stator core is constructed by laminating electromagnetic steel sheets in the axial direction, and a winding is wound around the stator core in a distributed winding manner, wherein the stator core has a plurality of slots in the circumferential direction, and the winding has a first winding and a second winding, the first winding and the second winding are connected in parallel, the first winding has a first outer layer winding and a first inner and outer layer winding connected in series, the second winding has a first inner layer winding and a second inner and outer layer winding connected in series, and in a plane perpendicular to the axial direction, when the circle passing through the outermost diameter portion of the slots in the radial direction with respect to the rotation axis of the stator core is defined as the first circle, the circle passing through the innermost diameter portion of the stator core in the radial direction with respect to the rotation axis of the stator core is defined as the second circle, and the circle bisecting the first circle and the second circle in the radial direction with respect to the rotation axis of the stator core is defined as the third circle, The first outer layer winding is arranged across two slots, with either the radial center or the center of gravity of the first outer layer winding located on the outer side of the third circle in one slot and the other slot; the first inner layer winding is arranged across two slots, with either the radial center or the center of gravity of the first inner layer winding located on the outer side of the third circle in one slot and either the radial center or the center of gravity of the first inner layer winding located on the inner side of the third circle in the other slot; the first inner layer winding is arranged across two slots, with either the radial center or the center of gravity of the first inner layer winding located on the inner side of the third circle in one slot and the other slot; In a stator, the second inner and outer layer windings are arranged across two slots, with the radial center or centroid of the second inner and outer layer windings located on the outer diameter side of the third circle in one slot, and the radial center or centroid of the second inner and outer layer windings located on the inner diameter side of the third circle in the other slot, the windings are formed in multiple phases, only windings of the same phase are arranged in one slot, the first inner layer windings of each phase are arranged at different positions in the circumferential direction, and the first inner layer windings of each phase are formed such that no first inner layer windings of other phases are arranged between the slots where the first inner layer windings of one phase are arranged.

2. The stator according to claim 1, wherein the first winding further comprises a third inner / outer layer winding connected in series with the first inner / outer layer winding, the second winding further comprises a fourth inner / outer layer winding connected in series with the second inner / outer layer winding, the third inner / outer layer winding is arranged across two slots, in one slot either the radial center or the centroid of the third inner / outer layer winding is located on the outer diameter side of the third circle, and in the other slot either the radial center or the centroid of the third inner / outer layer winding is located on the inner diameter side of the third circle, and the fourth inner / outer layer winding is arranged across two slots, in one slot either the radial center or the centroid of the fourth inner / outer layer winding is located on the outer diameter side of the third circle, and in the other slot either the radial center or the centroid of the fourth inner / outer layer winding is located on the inner diameter side of the third circle.

3. The stator according to claim 1, wherein the first winding further comprises a second inner layer winding connected in series with the first inner and outer layer windings, the second winding further comprises a second outer layer winding connected in series with the second inner and outer layer windings, the second inner layer winding is arranged across two slots, with either the radial center or the centroid of the second inner layer winding located inward from the third circle in one slot and the other slot, and the second outer layer winding is arranged across two slots, with either the radial center or the centroid of the second outer layer winding located outward from the third circle in one slot and the other slot.

4. The stator according to any one of claims 1 to 3, wherein the first winding and the second winding are connected to a neutral point.

5. The stator according to any one of claims 1 to 4, wherein the winding has three phases and is configured in a Y-connection.

6. The stator according to any one of claims 1 to 5, wherein the winding has a coil end extending radially to the outside of the axial end face of the stator core, and there is a gap between the axial end face of the stator core and the coil end.

7. An electric motor comprising a stator according to any one of claims 1 to 6 and a rotor, wherein the rotor has permanent magnets and a rotor core, the rotor core is constructed by laminating electromagnetic steel sheets in the axial direction and is provided with magnet insertion holes, one or more magnet insertion holes are provided for one magnetic pole, and the permanent magnets are inserted to form magnetic poles of number P.

8. A compressor comprising: an electric motor according to claim 7; and a compression mechanism driven by the electric motor.

9. An air conditioning system comprising the compressor, condenser, pressure reducing device, and evaporator described in claim 8.

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