Rotating electrical machine

Abstract

To provide a rotary electric machine capable of rotating at high speed.SOLUTION: An electric motor comprises a stator, and a rotor capable of rotating relatively to the stator. The stator includes a stator core including a cylindrical yoke part and 12 teeth protruding from the yoke part to the radially inside, and a three-phase coil in which windings are concentratedly wound around the teeth. The number of poles of the rotor is 2. Two teeth, out of the teeth, that are adjacent in the circumferential direction constitute a tooth part, and in-phase windings are wound around the tooth part continuously in series and in the same direction. The teeth are arranged so that the adjacent tooth parts have their phases differentiated, and each phase, out of the three phases, is aligned in order in the circumferential direction.SELECTED DRAWING: Figure 5

Description

Technical Field

[0001] The present disclosure relates to a rotating electrical machine.

Background Art

[0002] Japanese Unexamined Patent Application Publication No. 2006-296146 (Patent Document 1) discloses a stator of an electric motor in which tooth portions are arranged annularly, a resin bobbin is attached to the tooth portions, and windings are concentrically wound on the resin bobbin. The starting wire of the winding is wound around the side surface of the tooth portion on the inner-tooth side of the slot of the resin bobbin attached to the tooth portion, and after finishing the winding of the final turn of the tooth portion, the winding is led to an adjacent tooth portion by a jumper wire.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In an electric motor that requires high-speed rotation, from a control perspective, it is desirable that the number of poles be minimized to 2 poles. In the electric motor described in the above document, since the winding directions of the windings are wound in opposite directions in adjacent tooth portions, the number of poles has to be increased, making it difficult to cope with high-speed rotation.

[0005] In the present disclosure, a rotating electrical machine capable of high-speed rotation is proposed.

Means for Solving the Problems

[0006] The inventor of the present invention has intensively studied a rotating electrical machine capable of high-speed rotation, and in order to realize a rotating electrical machine with a simple and small structure having 2 poles and 12 slots, the following configuration has been devised.

[0007] That is, according to the present disclosure, a rotating electrical machine is proposed, which includes a stator and a rotor that can rotate relative to the stator. The stator includes a stator core including a cylindrical yoke portion and twelve teeth protruding radially inward from the yoke portion, and a three-phase coil in which windings are wound around the teeth in concentrated winding. The number of poles of the rotor is two poles. The teeth are such that two adjacent teeth in the circumferential direction are defined as a tooth portion, and windings of the same phase are connected in series to the tooth portion and wound in the same direction. The teeth are arranged such that adjacent tooth portions have different phases and each of the three phases is arranged in order in the circumferential direction.

[0008] As a result, a rotating electrical machine with a two-pole twelve-slot configuration that is simple in structure and small in size can be realized. Since the number of poles is the minimum of two poles, the rotating electrical machine can rotate at high speed.

[0009] In the above rotating electrical machine, the three-phase coils are arranged in the order of the first-phase coil, the second-phase coil, and the third-phase coil with respect to six tooth portions arranged in the circumferential direction. The second-phase coil is mounted on the tooth portion adjacent to the tooth portion on which the first-phase coil is mounted. A first-phase lead wire is drawn from one of the windings of the first-phase coil toward the neutral point, and a second-phase lead wire is drawn from one of the windings of the second-phase coil toward the neutral point. The winding forming the first-phase coil from which the first-phase lead wire is drawn and the winding forming the second-phase coil from which the second-phase lead wire is drawn may each be wound around two adjacent teeth in the circumferential direction.

[0010] Both the first-phase coil and the second-phase coil mounted on two adjacent tooth portions are connected to the neutral point, and the potential difference between the winding forming the first-phase coil and the winding forming the second-phase coil is reduced to a level where insulation is not required. As a result, the phase insulation between the first-phase coil and the second-phase coil can be made unnecessary, and the locations where phase insulation is required in the stator can be reduced.

[0011] In the above-described rotating electrical machine, a coil of a third phase is mounted on a tooth portion adjacent to and on the opposite side of a tooth portion on which a coil of a second phase is mounted with respect to a tooth portion on which a coil of a first phase is mounted. The stator is disposed between a winding forming an adjacent coil of the first phase and a winding forming a coil of the third phase, and may further include an inter-phase insulator that insulates the winding forming the coil of the first phase and the winding forming the coil of the third phase. By disposing an inter-phase insulator between the coil of the first phase and the coil of the third phase, the coil of the first phase and the coil of the third phase can be reliably insulated from each other.

[0012] The above-described rotating electrical machine further includes three-phase power supply conductors that constitute a power supply path to the three-phase coils, and a neutral conductor that electrically connects the three-phase coils and a neutral point. The three-phase power supply conductors and the neutral conductor are disposed along the yoke portion and each have an arc shape. The three-phase power supply conductors and the neutral conductor are positioned by an annular resin, and the number of the three-phase power supply conductors and the neutral conductor arranged in the radial direction may be three or less. Thereby, the arrangement space of the conductors can be reduced, and the stator can be miniaturized.

[0013] In the above-described rotating electrical machine, the three-phase power supply conductors include a first-phase power supply conductor, a second-phase power supply conductor, and a third-phase power supply conductor. The second-phase power supply conductor may have a first portion disposed outside the first-phase power supply conductor in the radial direction and a second portion disposed inside the third-phase power supply conductor in the radial direction. In this way, a configuration can be realized in which the number of the three-phase power supply conductors and the neutral conductor arranged in the radial direction is three or less.

Advantages of the Invention

[0014] The rotating electrical machine of the present disclosure can rotate at high speed.

Brief Description of the Drawings

[0015]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Mode for Carrying Out the Invention

[0016] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the following description of the embodiments, the same or substantially the same configurations are denoted by the same reference numerals, and redundant descriptions will not be repeated.

[0017] FIG. 1 is a partial cross-sectional view showing a schematic configuration of an electric compressor 110 including a rotating electric machine according to an embodiment. The electric compressor 110 is, as an example, a turbo-type air pump mounted on a fuel cell vehicle and driven by high-speed rotation.

[0018] As shown in FIG. 1, the electric compressor 110 includes a housing 112, a compression unit 115, and an electric motor 1.

[0019] An electric motor 1 as an example of a rotating electric machine according to the embodiment includes a rotor 3 and a stator 4. The rotor 3 is fixed to the rotating shaft 2. The rotating shaft 2 is rotatably supported in the housing 112 while being inserted into the stator 4. The stator 4 is configured to include a stator core 10 and a coil 20. The stator core 10 is fixed to the inner peripheral surface of the housing 112. The coil 20 is attached to teeth of the stator core 10, which will be described later.

[0020] When power is supplied to the electric motor 1, the rotor 3 and the rotating shaft 2 rotate relative to the stator 4 and the housing 112. Due to this rotation, the compression section 115 is driven. When the compression section 115 is driven, air is supplied to the fuel cell.

[0021] FIG. 2 is a schematic plan view of the stator core 10. FIG. 2 shows a schematic shape of the stator core 10 as viewed in the axial direction of the electric motor 1 (in FIG. 1, the left - right direction in the drawing). The stator core 10 may be formed by laminating a plurality of annular electromagnetic steel sheets, or may be formed from an integral member made of a magnetic material.

[0022] As shown in FIG. 2, the stator core 10 as a whole has a hollow cylindrical outer shape. In the following embodiments, the axial direction of the cylindrical stator core 10 will simply be referred to as the axial direction, the radial direction of the stator core 10 will simply be referred to as the radial direction, and the circumferential direction of the stator core 10 will simply be referred to as the circumferential direction for explanation.

[0023] The stator core 10 includes a cylindrical yoke portion 12 and a plurality of teeth 16. The teeth 16 project radially inward from the inner peripheral surface of the yoke portion 12. The teeth 16 are arranged at intervals in the circumferential direction of the stator core 10. A slot 18 extending along the axial direction is formed between two adjacent teeth 16. The stator core 10 of the embodiment has 12 teeth 16. The number of slots 18 is also 12, the same as the number of teeth 16.

[0024] More specifically, the stator core 10 includes twelve teeth 1601 - 1612. A slot 1801 is formed between the adjacent teeth 1601 and 1602 in the circumferential direction. A slot 1802 is formed between the adjacent teeth 1602 and 1603 in the circumferential direction. A slot 1803 is formed between the adjacent teeth 1603 and 1604 in the circumferential direction. A slot 1804 is formed between the adjacent teeth 1604 and 1605 in the circumferential direction.

[0025] A slot 1805 is formed between adjacent teeth 1605 and 1606 in the circumferential direction. A slot 1806 is formed between adjacent teeth 1606 and 1607 in the circumferential direction. A slot 1807 is formed between adjacent teeth 1607 and 1608 in the circumferential direction. A slot 1808 is formed between adjacent teeth 1608 and 1609 in the circumferential direction.

[0026] A slot 1809 is formed between adjacent teeth 1609 and 1610 in the circumferential direction. A slot 1810 is formed between adjacent teeth 1610 and 1611 in the circumferential direction. A slot 1811 is formed between adjacent teeth 1611 and 1612 in the circumferential direction. A slot 1812 is formed between adjacent teeth 1612 and 1601 in the circumferential direction.

[0027] Two adjacent teeth 1601 and 1602 in the circumferential direction constitute a tooth portion 171. Two adjacent teeth 1603 and 1604 in the circumferential direction constitute a tooth portion 172. Two adjacent teeth 1605 and 1606 in the circumferential direction constitute a tooth portion 173. Two adjacent teeth 1607 and 1608 in the circumferential direction constitute a tooth portion 174. Two adjacent teeth 1609 and 1610 in the circumferential direction constitute a tooth portion 175. Two adjacent teeth 1611 and 1612 in the circumferential direction constitute a tooth portion 176.

[0028] FIG. 3 is a schematic plan view of the electric motor 1. Windings are wound around each of the 12 teeth 16 in concentrated winding to form a three-phase coil 20. The three-phase coil 20 includes a U-phase coil formed by winding the U-phase winding around the teeth 16, a V-phase coil formed by winding the V-phase winding around the teeth 16, and a W-phase coil formed by winding the W-phase winding around the teeth 16. In the present embodiment, 12 coils are arranged side by side in the circumferential direction, and each phase coil is composed of 4 coils 20 respectively.

[0029] Specifically, a U-phase coil 24Up1 is mounted on the tooth 1601. A U-phase coil 24Up2 is mounted on the tooth 1602. The teeth 1601 and 1602 constitute a tooth portion 171 (FIG. 2), and the U-phase windings of the same phase are wound around the tooth portion 171 to form a U-phase coil.

[0030] A V-phase coil 34Vm3 is mounted on the tooth 1603. A V-phase coil 34Vm4 is mounted on the tooth 1604. The teeth 1603 and 1604 constitute a tooth portion 172 (FIG. 2), and the V-phase windings of the same phase are wound around the tooth portion 172 to form a V-phase coil.

[0031] A W-phase coil 44Wp5 is mounted on the tooth 1605. A W-phase coil 44Wp6 is mounted on the tooth 1606. The teeth 1605 and 1606 constitute a tooth portion 173 (FIG. 2), and the W-phase windings of the same phase are wound around the tooth portion 173 to form a W-phase coil.

[0032] A U-phase coil 24Um7 is mounted on the tooth 1607. A U-phase coil 24Um8 is mounted on the tooth 1608. The teeth 1607 and 1608 constitute a tooth portion 174 (FIG. 2), and the U-phase windings of the same phase are wound around the tooth portion 174 to form a U-phase coil.

[0033] The V-phase coil 34Vp9 is mounted on the tooth 1609. The V-phase coil 34Vp10 is mounted on the tooth 1610. The teeth 1609 and 1610 constitute the tooth portion 175 (Fig. 2), and the windings of the V-phase of the same phase are wound around the tooth portion 175 to form the V-phase coil.

[0034] The W-phase coil 44Wm11 is mounted on the tooth 1611. The W-phase coil 44Wm12 is mounted on the tooth 1612. The teeth 1611 and 1612 constitute the tooth portion 176 (Fig. 2), and the windings of the W-phase of the same phase are wound around the tooth portion 176 to form the W-phase coil.

[0035] The windings of the U-phase are wound around each of two adjacent teeth 16 to form two U-phase coils. For example, the U-phase coils 24Up1 and 24Up2 are mounted on the adjacent teeth 1601 and 1602 that constitute the tooth portion 171. The windings of the V-phase are wound around the two teeth 16 adjacent to the two teeth 16 on which the U-phase coils are mounted to form two V-phase coils. For example, the V-phase coils 34Vm3 and 34Vm4 are mounted on the teeth 1603 and 1604 that constitute the tooth portion 172 adjacent to the tooth portion 171.

[0036] The windings of the W-phase are wound around the teeth 16 adjacent to the two teeth 16 on the opposite side of the V-phase coil with respect to the two teeth 16 around which the windings of the U-phase are wound to form the W-phase coil. For example, the W-phase coils 44Wm11 and 44Wm12 are mounted on the teeth 1611 and 1612 that constitute the tooth portion 176 on the opposite side of the tooth portion 172 on which the V-phase coil is mounted with respect to the tooth portion 171.

[0037] The teeth 16 are arranged such that adjacent tooth portions are out of phase and the phases of the three phases are arranged in order in the circumferential direction. The three-phase coils are arranged in the order of the first-phase coil, the second-phase coil, and the third-phase coil with respect to six tooth portions 171 to 176 arranged in the circumferential direction. A U-phase coil is mounted on the tooth portion 171. A V-phase coil is mounted on the tooth portion 172 adjacent to the tooth portion 171. A W-phase coil is mounted on the tooth portion 173 adjacent to the tooth portion 172. A U-phase coil is mounted on the tooth portion 174 adjacent to the tooth portion 173. A V-phase coil is mounted on the tooth portion 175 adjacent to the tooth portion 174. A W-phase coil is mounted on the tooth portion 176 adjacent to the tooth portion 175.

[0038] The U-phase coil 24Up1 and the W-phase coil 44Wm12 are adjacent to each other in the circumferential direction, and phase insulation paper 61 is disposed between the U-phase winding forming the U-phase coil 24Up1 and the W-phase winding forming the W-phase coil 44Wm12. The phase insulation paper 61 is an example of a phase insulator and insulates the U-phase winding forming the U-phase coil 24Up1 and the W-phase winding forming the W-phase coil 44Wm12.

[0039] Also, phase insulation paper 62 is disposed between the V-phase winding forming the V-phase coil 34Vm4 and the W-phase winding forming the W-phase coil 44Wp5. The phase insulation paper 62 insulates the V-phase winding forming the V-phase coil 34Vm4 and the W-phase winding forming the W-phase coil 44Wp5. Phase insulation paper 63 is disposed between the U-phase winding forming the U-phase coil 24Um8 and the V-phase winding forming the V-phase coil 34Vp9. The phase insulation paper 63 insulates the U-phase winding forming the U-phase coil 24Um8 and the V-phase winding forming the V-phase coil 34Vp9.

[0040] As shown in FIG. 3, the rotor 3 has an N - pole core portion 3N and an S - pole core portion 3S, and the number of poles of the rotor 3 is two poles. The rotor 3 may be an IPM (Interior Permanent Magnet) type rotor in which permanent magnets are embedded in each core portion, or may be an SPM (Surface Permanent Magnet) type rotor in which magnets are attached to the surface of each core portion.

[0041] FIG. 4 is a schematic diagram showing the winding wound around the tooth 16. As shown in FIG. 4, a bobbin 70 is mounted on the tooth 16. The bobbin 70 is made of an insulating material typified by resin. The bobbin 70 is arranged so as to surround the outer periphery of the tooth 16. The winding constituting the coil 20 is wound in a laminated manner around the bobbin 70. The bobbin 70 is an insulating member that electrically insulates the stator core 10 and the coil 20. The bobbin 70 has a winding portion 71, a first flange portion 72, and a second flange portion 73.

[0042] The winding portion 71 has a cylindrical shape and extends in the radial direction. The bobbin 70 is relatively moved with respect to the stator core 10 so that the tooth 16 is inserted into the inside of the winding portion 71, and the bobbin 70 is attached to the stator core 10. The inner peripheral surface of the winding portion 71 faces the tooth 16. The inner peripheral surface of the winding portion 71 is in contact with the tooth 16. The winding is wound in a laminated manner on the outer peripheral surface of the winding portion 71.

[0043] The first flange portion 72 is provided at the radially outer end of the winding portion 71 and extends in the circumferential direction and the axial direction. The first flange portion 72 is in contact with the inner peripheral surface of the yoke portion 12. The second flange portion 73 is provided at the radially inner end of the winding portion 71 and extends in the circumferential direction and the axial direction.

[0044] As shown in FIG. 4, the starting winding is guided to a position where it contacts the winding portion 71 and the first flange portion 72, and is wound around the winding portion 71. The winding is wound around the winding portion 71 while heading radially inward (in FIG. 4, the lower side in the figure). When the winding reaches the second flange portion 73, it is folded back to the second layer, and the winding is wound around the first layer winding while heading radially outward (in FIG. 4, the upper side in the figure).

[0045] Similarly, the third layer winding is wound around the second layer winding while heading radially inward, the fourth layer winding is wound around the third layer winding while heading radially outward, and the fifth layer winding is wound around the fourth layer winding while heading radially inward. The sixth layer winding is wound around the fifth layer winding near the first flange portion 72 to complete the winding.

[0046] The second layer winding is farther from the teeth 16 than the first layer winding. The third layer winding is farther from the teeth 16 than the second layer winding. The sixth layer winding at the end of the winding is the farthest from the teeth 16. The winding is farther from the teeth 16 as it goes from the start to the end of the winding around the teeth 16. The power supply side lead wire described later is drawn out from the innermost diameter side of the winding wound in layers around the teeth 16. The neutral point side lead wire described later is drawn out from the outermost diameter side of the winding wound in layers around the teeth 16.

[0047] FIG. 4 exemplarily shows a winding wound in six layers around the bobbin 70. The number of layers of the winding wound around the bobbin 70 may be five or less, or may be seven or more. The number of windings in each layer arranged between the first flange portion 72 and the second flange portion 73 is also arbitrary.

[0048] FIG. 5 is a wiring diagram of the stator 4. The U-phase input terminal 21U, the V-phase input terminal 31V, and the W-phase input terminal 41W are electrically connected to an inverter (not shown). Three-phase AC power is input to the U-phase input terminal 21U, the V-phase input terminal 31V, and the W-phase input terminal 41W.

[0049] A U-phase power supply conductor 22U is connected to a U-phase input terminal 21U. A U-phase power supply side lead wire 23U1 is drawn from the starting end of the winding of a U-phase coil 24Up1, and the U-phase power supply side lead wire 23U1 is connected to the U-phase power supply conductor 22U. The U-phase input terminal 21U, the U-phase power supply conductor 22U, and the U-phase power supply side lead wire 23U1 constitute a power supply path to the U-phase coils 24Up1 and 24Up2.

[0050] When the U-phase coil 24Up1 and the U-phase coil 24Up2 are viewed from the same direction, the winding directions of the windings are the same. The U-phase winding forming the U-phase coil 24Up1 shown in FIG. 5 is wound around the teeth 1601 (FIGS. 2 and 3) in the counterclockwise direction, and the U-phase winding forming the U-phase coil 24Up2 is wound around the teeth 1602 in the counterclockwise direction. The U-phase windings of the same phase are wound around the circumferentially adjacent teeth 1601 and 1602 in the same direction.

[0051] A U-phase crossover conductor 25U12 is connected to the U-phase coil 24Up1 and the U-phase coil 24Up2. The U-phase crossover conductor 25U12 electrically connects the end of the winding of the U-phase coil 24Up1 and the starting end of the winding of the U-phase coil 24Up2 to each other. The circumferentially adjacent U-phase coils 24Up1 and 24Up2 are connected in series via the U-phase crossover conductor 25U12. The U-phase crossover conductor 25U12 may be arranged on the radially outer side of the first flange portion 72 of the bobbin 70 or on the radially inner side of the first flange portion 72.

[0052] A U-phase neutral point side lead wire 26U2 is drawn from the end of the winding of the U-phase coil 24Up2. The U-phase neutral point side lead wire 26U2 is connected to the neutral point 52 via a neutral conductor 54. The neutral conductor 54 electrically connects the U-phase coil 24Up2 and the neutral point 52.

[0053] The U-phase power supply side lead wire 23U8 is drawn from the starting end of the winding of the U-phase coil 24Um8, and the U-phase power supply side lead wire 23U8 is connected to the U-phase power supply conductor 22U. The U-phase input terminal 21U, the U-phase power supply conductor 22U, and the U-phase power supply side lead wire 23U8 constitute a power supply path to the U-phase coils 24Um8 and 24Um7.

[0054] When the U-phase coil 24Um8 and the U-phase coil 24Um7 are viewed from the same direction, the winding directions of the windings are the same. The U-phase winding forming the U-phase coil 24Um8 shown in FIG. 5 is wound around the tooth 1608 in the clockwise direction, and the U-phase winding forming the U-phase coil 24Um7 is wound around the tooth 1607 in the clockwise direction. The U-phase windings of the same phase are wound in the same direction around the circumferentially adjacent teeth 1607 and 1608.

[0055] The U-phase cross conductor 25U78 is connected to the U-phase coil 24Um7 and the U-phase coil 24Um8. The U-phase cross conductor 25U78 electrically connects the ending end of the winding of the U-phase coil 24Um8 and the starting end of the winding of the U-phase coil 24Um7 to each other. The circumferentially adjacent U-phase coils 24Um7 and 24Um8 are connected in series via the U-phase cross conductor 25U78. The U-phase cross conductor 25U78 may be arranged on the radially outer side of the first flange portion 72 of the bobbin 70 or on the radially inner side of the first flange portion 72.

[0056] The U-phase neutral point side lead wire 26U7 is drawn from the ending end of the winding of the U-phase coil 24Um7. The U-phase neutral point side lead wire 26U7 is connected to the neutral point 51.

[0057] The V-phase power supply conductor 32V is connected to the V-phase input terminal 31V. The V-phase power supply side lead wire 33V4 is drawn from the starting end of the winding of the V-phase coil 34Vm4, and the V-phase power supply side lead wire 33V4 is connected to the V-phase power supply conductor 32V. The V-phase input terminal 31V, the V-phase power supply conductor 32V, and the V-phase power supply side lead wire 33V4 constitute a power supply path to the V-phase coils 34Vm4 and 34Vm3.

[0058] When the V-phase coil 34Vm4 and the V-phase coil 34Vm3 are viewed from the same direction, the winding directions of the windings are the same. The V-phase winding forming the V-phase coil 34Vm4 shown in FIG. 5 is wound around the tooth 1604 in the clockwise direction, and the V-phase winding forming the V-phase coil 34Vm3 is wound around the tooth 1603 in the clockwise direction. The V-phase windings of the same phase are wound in the same direction around the circumferentially adjacent teeth 1603 and 1604.

[0059] The V-phase jumper conductor 35V34 is connected to the V-phase coil 34Vm3 and the V-phase coil 34Vm4. The V-phase jumper conductor 35V34 electrically connects the winding end portion of the V-phase coil 34Vm4 and the winding start portion of the V-phase coil 34Vm3 to each other. The circumferentially adjacent V-phase coils 34Vm3 and 34Vm4 are connected in series via the V-phase jumper conductor 35V34. The V-phase jumper conductor 35V34 may be disposed on the radially outer side of the first flange portion 72 of the bobbin 70 or may be disposed on the radially inner side of the first flange portion 72.

[0060] The V-phase neutral point side lead wire 36V3 is drawn out from the winding end portion of the V-phase coil 34Vm3. The V-phase neutral point side lead wire 36V3 is connected to the neutral point 52 via the neutral conductor 54. The neutral conductor 54 electrically connects the V-phase coil 34Vm3 and the neutral point 52.

[0061] The V-phase power supply side lead wire 33V9 is drawn out from the winding start portion of the V-phase coil 34Vp9, and the V-phase power supply side lead wire 33V9 is connected to the V-phase power supply conductor 32V. The V-phase input terminal 31V, the V-phase power supply conductor 32V, and the V-phase power supply side lead wire 33V9 constitute a power supply path to the V-phase coils 34Vp9 and 34Vp10.

[0062] When the V-phase coils 34Vp9 and 34Vp10 are viewed from the same direction, the winding directions of the windings are the same. The V-phase winding forming the V-phase coil 34Vp9 shown in FIG. 5 is wound around the tooth 1609 in the counterclockwise direction, and the V-phase winding forming the V-phase coil 34Vp10 is wound around the tooth 1610 in the counterclockwise direction. The V-phase windings of the same phase are wound in the same direction around the circumferentially adjacent teeth 1609 and 1610.

[0063] The V-phase jumper conductor 35V910 is connected to the V-phase coil 34Vp9 and the V-phase coil 34Vp10. The V-phase jumper conductor 35V910 electrically connects the winding end portion of the V-phase coil 34Vp9 and the winding start portion of the V-phase coil 34Vp10 to each other. The circumferentially adjacent V-phase coils 34Vp9 and 34Vp10 are connected in series via the V-phase jumper conductor 35V910. The V-phase jumper conductor 35V910 may be arranged on the radially outer side of the first flange portion 72 of the bobbin 70, or may be arranged on the radially inner side of the first flange portion 72.

[0064] The V-phase neutral point side lead wire 36V10 is drawn out from the winding end portion of the V-phase coil 34Vp10. The V-phase neutral point side lead wire 36V10 is connected to the neutral point 51 via the neutral conductor 53. The neutral conductor 53 is a member different from the neutral conductor 54. The neutral conductor 53 electrically connects the V-phase coil 34Vp10 and the neutral point 51.

[0065] The W-phase power supply conductor 42W is connected to the W-phase input terminal 41W. The W-phase power supply side lead wire 43W5 is drawn out from the winding start portion of the W-phase coil 44Wp5, and the W-phase power supply side lead wire 43W5 is connected to the W-phase power supply conductor 42W. The W-phase input terminal 41W, the W-phase power supply conductor 42W, and the W-phase power supply side lead wire 43W5 constitute a power supply path to the W-phase coils 44Wp5 and 44Wp6.

[0066] When viewing the W-phase coil 44Wp5 and the W-phase coil 44Wp6 from the same direction, the winding directions of the windings are the same. The W-phase winding forming the W-phase coil 44Wp5 shown in FIG. 5 is wound around the tooth 1605 in the counterclockwise direction, and the W-phase winding forming the W-phase coil 44Wp6 is wound around the tooth 1606 in the counterclockwise direction. The W-phase windings of the same phase are wound in the same direction around the circumferentially adjacent teeth 1605 and 1606.

[0067] The W-phase bridging conductor 45W56 is connected to the W-phase coil 44Wp5 and the W-phase coil 44Wp6. The W-phase bridging conductor 45W56 electrically connects the winding end of the W-phase coil 44Wp5 and the winding start end of the W-phase coil 44Wp6 to each other. The circumferentially adjacent W-phase coils 44Wp5 and 44Wp6 are connected in series via the W-phase bridging conductor 45W56. The W-phase bridging conductor 45W56 may be arranged on the radially outer side of the first flange portion 72 of the bobbin 70 or on the radially inner side of the first flange portion 72.

[0068] The W-phase neutral point side lead wire 46W6 is drawn out from the winding end of the W-phase coil 44Wp6. The W-phase neutral point side lead wire 46W6 is connected to the neutral point 51.

[0069] The W-phase power supply side lead wire 43W12 is drawn out from the winding start end of the W-phase coil 44Wm12, and the W-phase power supply side lead wire 43W12 is connected to the W-phase power supply conductor 42W. The W-phase input terminal 41W, the W-phase power supply conductor 42W, and the W-phase power supply side lead wire 43W12 constitute a power supply path to the W-phase coils 44Wm12 and 44Wm11.

[0070] When the W-phase coils 44Wm12 and 44Wm11 are viewed from the same direction, the winding directions of the windings are the same. The W-phase winding forming the W-phase coil 44Wm12 shown in Fig. 5 is wound around the tooth 1612 in the clockwise direction, and the W-phase winding forming the W-phase coil 44Wm11 is wound around the tooth 1611 in the clockwise direction. The W-phase windings of the same phase are wound in the same direction around the circumferentially adjacent teeth 1611 and 1612.

[0071] The W-phase bridging conductor 45W1112 is connected to the W-phase coil 44Wm11 and the W-phase coil 44Wm12. The W-phase bridging conductor 45W1112 electrically connects the winding end of the W-phase coil 44Wm12 and the winding start end of the W-phase coil 44Wm11 to each other. The circumferentially adjacent W-phase coils 44Wm11 and 44Wm12 are connected in series via the W-phase bridging conductor 45W1112. The W-phase bridging conductor 45W1112 may be arranged on the radially outer side of the first flange portion 72 of the bobbin 70, or may be arranged on the radially inner side of the first flange portion 72.

[0072] The W-phase neutral point side lead wire 46W11 is drawn out from the winding end of the W-phase coil 44Wm11. The W-phase neutral point side lead wire 46W11 is connected to the neutral point 52.

[0073] The plus and minus signs in Fig. 5 indicate the winding direction of the winding around the tooth 16. The U-phase coils 24Up1, 24Up2, the V-phase coils 34Vp9, 34Vp10, and the W-phase coils 44Wp5, 44Wp6 are all formed by winding the winding in the counterclockwise direction around the tooth 16 in Fig. 5. The U-phase coils 24Um7, 24Um8, the V-phase coils 34Vm3, 34Vm4, and the W-phase coils 44Wm11, 44Wm12 are all formed by winding the winding in the clockwise direction around the tooth 16 in Fig. 5.

[0074] The U-phase current flows through the U-phase coils 24Up1 and 24Up2. In the direction of the current flow, the U-phase coil 24Up1 is on the upstream side, and the U-phase coil 24Up2 is on the downstream side. From the upstream U-phase coil 24Up1, the U-phase power supply side lead wire 23U1 connected to the U-phase input terminal 41W is drawn out. From the downstream U-phase coil 24Up2, the U-phase neutral point side lead wire 26U2 towards the neutral point 52 is drawn out.

[0075] The V-phase current flows through the V-phase coils 34Vm3 and 34Vm4. In the direction of the current flow, the V-phase coil 34Vm4 is on the upstream side, and the V-phase coil 34Vm3 is on the downstream side. From the upstream V-phase coil 34Vm4, the V-phase power supply side lead wire 33V4 connected to the V-phase input terminal 31V is drawn out. From the downstream V-phase coil 34Vm3, the V-phase neutral point side lead wire 36V3 towards the neutral point 52 is drawn out.

[0076] The U-phase coil 24Up2 from which the U-phase neutral point side lead wire 26U2 is drawn out is mounted on the tooth 1602. The V-phase coil 34Vm3 from which the V-phase neutral point side lead wire 36V3 is drawn out is mounted on the tooth 1603. The U-phase coil 24Up2 and the V-phase coil 34Vm3 are each mounted on two circumferentially adjacent teeth 16. There is no phase insulation paper arranged between the U-phase winding forming the U-phase coil 24Up2 and the V-phase winding forming the V-phase coil 34Vm3.

[0077] The W-phase current flows through the W-phase coils 44Wp5 and 44Wp6. In the direction of the current flow, the W-phase coil 44Wp5 is on the upstream side, and the W-phase coil 44Wp6 is on the downstream side. From the upstream W-phase coil 44Wp5, the W-phase power supply side lead wire 43W5 connected to the W-phase input terminal 41W is drawn out. From the downstream W-phase coil 44Wp6, the W-phase neutral point side lead wire 46W6 towards the neutral point 51 is drawn out.

[0078] The U-phase windings are wound around two teeth 1601 and 1602 adjacent to the teeth 1603 and 1604 around which the V-phase windings are wound, forming U-phase coils 24Up1 and 24Up2. The W-phase windings are wound around two teeth 1605 and 1606 adjacent to the teeth 1603 and 1604 on the side opposite to the U-phase coils 24Up1 and 24Up2, forming W-phase coils 44Wp5 and 44Wp6. An inter-phase insulating paper 62 is arranged between the V-phase coil 34Vm4 and the W-phase coil 44Wp5. The inter-phase insulating paper 62 electrically insulates the V-phase winding forming the V-phase coil 34Vm4 and the W-phase winding forming the W-phase coil 44Wp5.

[0079] A U-phase current flows through the U-phase coils 24Um7 and 24Um8. In the direction of the current flow, the U-phase coil 24Um8 is on the upstream side and the U-phase coil 24Um7 is on the downstream side. A U-phase power supply side lead wire 23U8 connected to the U-phase input terminal 21U is drawn out from the upstream U-phase coil 24Um8. A U-phase neutral point side lead wire 26U7 leading to the neutral point 51 is drawn out from the downstream U-phase coil 24Um7.

[0080] The W-phase coil 44Wp6 from which the W-phase neutral point side lead wire 46W6 is drawn out is mounted on the tooth 1606. The U-phase coil 24Um7 from which the U-phase neutral point side lead wire 26U7 is drawn out is mounted on the tooth 1607. The W-phase coil 44Wp6 and the U-phase coil 24Um7 are each mounted on two teeth 16 adjacent to each other in the circumferential direction. An inter-phase insulating paper is not arranged between the W-phase winding forming the W-phase coil 44Wp6 and the U-phase winding forming the U-phase coil 24Um7.

[0081] A V-phase current flows through the V-phase coils 34Vp9 and 34Vp10. In the direction of the current flow, the V-phase coil 34Vp9 is on the upstream side and the V-phase coil 34Vp10 is on the downstream side. A V-phase power supply side lead wire 33V9 connected to the V-phase input terminal 31V is drawn out from the upstream V-phase coil 34Vp9. A V-phase neutral point side lead wire 36V10 leading to the neutral point 51 is drawn out from the downstream V-phase coil 34Vp10.

[0082] The W-phase windings are wound around two adjacent teeth 1605 and 1606 adjacent to the teeth 1607 and 1608 around which the U-phase windings are wound, forming W-phase coils 44Wp5 and 44Wp6. The V-phase windings are wound around two adjacent teeth 1609 and 1610 on the opposite side of the teeth 1607 and 1608 from the W-phase coils 44Wp5 and 44Wp6, forming V-phase coils 34Vp9 and 34Vp10. An interphase insulating paper 63 is disposed between the U-phase coil 24Um8 and the V-phase coil 34Vp9. The interphase insulating paper 63 electrically insulates the U-phase winding forming the U-phase coil 24Um8 and the V-phase winding forming the V-phase coil 34Vp9.

[0083] A W-phase current flows through the W-phase coils 44Wm11 and 44Wm12. In the direction of the current flow, the W-phase coil 44Wm12 is on the upstream side and the W-phase coil 44Wm11 is on the downstream side. A W-phase power supply side lead wire 43W12 connected to the W-phase input terminal 41W is drawn out from the upstream W-phase coil 44Wm12. A W-phase neutral point side lead wire 46W11 leading to the neutral point 52 is drawn out from the downstream W-phase coil 44Wm11.

[0084] The V-phase coil 34Vp10 from which the V-phase neutral point side lead wire 36V10 is drawn out is mounted on the tooth 1610. The W-phase coil 44Wm11 from which the W-phase neutral point side lead wire 46W11 is drawn out is mounted on the tooth 1611. The V-phase coil 34Vp10 and the W-phase coil 44Wm11 are each mounted on two circumferentially adjacent teeth 16. No interphase insulating paper is disposed between the V-phase winding forming the V-phase coil 34Vp10 and the W-phase winding forming the W-phase coil 44Wm11.

[0085] The V-phase windings are wound around two adjacent teeth 1609 and 1610 adjacent to the teeth 1611 and 1612 around which the W-phase windings are wound, forming V-phase coils 34Vp9 and 34Vp10. The U-phase windings are wound around two adjacent teeth 1601 and 1602 (see FIGS. 2 and 3) on the opposite side of the teeth 1611 and 1612 from the V-phase coils 34Vp9 and 34Vp10, forming U-phase coils 24Up1 and 24Up2. An interphase insulating paper 61 is disposed between the W-phase coil 44Wm12 and the U-phase coil 24Up1. The interphase insulating paper 61 electrically insulates the W-phase winding forming the W-phase coil 44Wm12 and the U-phase winding forming the U-phase coil 24Up1.

[0086] In the U-phase coils 24Up1 and 24Up2, V-phase coils 34Vp9 and 34Vp10, and W-phase coils 44Wp5 and 44Wp6 formed by winding the windings counterclockwise around the teeth 16 in FIG. 5, each coil 20 on the upstream side in the current flow direction is disposed on the left side in FIG. 5 (the counterclockwise direction side in FIGS. 2 and 3). In the U-phase coils 24Um7 and 24Um8, V-phase coils 34Vm3 and 34Vm4, and W-phase coils 44Wm11 and 44Wm12 formed by winding the windings clockwise around the teeth 16 in FIG. 5, each coil 20 on the upstream side in the current flow direction is disposed on the right side in FIG. 5 (the clockwise direction side in FIGS. 2 and 3).

[0087] The U-phase neutral-point side lead wire 26U7 drawn from the U-phase coil 24Um7, the V-phase neutral-point side lead wire 36V10 drawn from the V-phase coil 34Vp10, and the W-phase neutral-point side lead wire 46W6 drawn from the W-phase coil 44Wp6 are electrically connected at the neutral point 51. The U-phase neutral-point side lead wire 26U2 drawn from the U-phase coil 24Up2, the V-phase neutral-point side lead wire 36V3 drawn from the V-phase coil 34Vm3, and the W-phase neutral-point side lead wire 46W11 drawn from the W-phase coil 44Wm11 are electrically connected at the neutral point 52.

[0088] The neutral points 51 and 52 are at the same potential. The neutral points 51 and 52 are grounded and have the same zero potential. The potential difference between the neutral point 51 and the neutral point 52 is maintained at approximately zero.

[0089] The U-phase power supply conductor 22U, the V-phase power supply conductor 32V, the W-phase power supply conductor 42W, and the neutral conductors 53 and 54 shown in FIG. 5 may be composed of windings or may be composed of busbars. FIG. 6 is a perspective view of the annular busbar 80. FIG. 7 is a schematic view of the annular busbar 80 in a plan view.

[0090] As shown in FIGS. 6 and 7, the U-phase power supply conductor 22U, the V-phase power supply conductor 32V, the W-phase power supply conductor 42W, and the neutral conductors 53 and 54 are each composed of a busbar having a substantially arc-shaped shape in a plan view. By arranging these busbars, an annular busbar 80 having a substantially annular shape in a plan view is formed. The U-phase power supply conductor 22U, the V-phase power supply conductor 32V, the W-phase power supply conductor 42W, and the neutral conductors 53 and 54 are arranged with a gap therebetween.

[0091] FIG. 8 is a schematic view showing the resin 81 covering the annular busbar 80. Among the conductors shown in FIG. 7, the portions covered with the resin 81 in FIG. 8 are indicated by broken lines. The U-phase power supply conductor 22U, the V-phase power supply conductor 32V, the W-phase power supply conductor 42W, and the neutral conductors 53 and 54 are integrated by the annular resin 81. The resin 81 ensures insulation between the U-phase power supply conductor 22U, the V-phase power supply conductor 32V, the W-phase power supply conductor 42W, and the neutral conductors 53 and 54. The resin 81 also has a function of positioning the U-phase power supply conductor 22U, the V-phase power supply conductor 32V, the W-phase power supply conductor 42W, and the neutral conductors 53 and 54.

[0092] In the annular bus bar 80, the neutral conductors 53 and 54 are arranged on the innermost side in the radial direction. The neutral conductor 53 and the neutral conductor 54 have the same curvature and are arranged concentrically. The U-phase power supply conductor 22U has a smaller curvature than the neutral conductors 53 and 54 and is arranged on the outside in the radial direction of the neutral conductors 53 and 54. The W-phase power supply conductor 42W has a smaller curvature than the U-phase power supply conductor 22U and is arranged on the outside in the radial direction of the U-phase power supply conductor 22U.

[0093] The V-phase power supply conductor 32V has a first portion 32V1 arranged on the outside in the radial direction of the U-phase power supply conductor 22U and a second portion 32V2 arranged on the inside in the radial direction of the W-phase power supply conductor 42W. The second portion 32V2 is arranged between the neutral conductors 53 and 54 and the W-phase power supply conductor 42W in the radial direction.

[0094] The first portion 32V1 of the V-phase power supply conductor 32V and the W-phase power supply conductor 42W have the same curvature and are arranged concentrically. The second portion 32V2 of the V-phase power supply conductor 32V and the U-phase power supply conductor 22U have the same curvature and are arranged concentrically. The V-phase power supply conductor 32V changes its position in the radial direction at the connecting portion between the first portion 32V1 and the second portion 32V2. The first portion 32V1 is arranged on the outside in the radial direction of the second portion 32V2. The first portion 32V1 has a smaller curvature than the second portion 32V2.

[0095] The U-phase input terminal 21U is integrally formed with the U-phase power supply conductor 22U and extends radially outward from the arc-shaped portion of the U-phase power supply conductor 22U. The V-phase input terminal 31V is integrally formed with the V-phase power supply conductor 32V and extends radially outward from the arc-shaped portion of the V-phase power supply conductor 32V. The W-phase input terminal 41W is integrally formed with the W-phase power supply conductor 42W and extends radially outward from the arc-shaped portion of the W-phase power supply conductor 42W.

[0096] The U-phase power supply conductor 22U, V-phase power supply conductor 32V, W-phase power supply conductor 42W, and neutral conductors 53, 54 that make up the annular bus bar 80 are arranged side by side at intervals in the radial direction. At any position in the circumferential direction of the annular bus bar 80, the number of conductors arranged in the radial direction at the same circumferential position is 3 or less. For example, at the position where the U-phase input terminal 21U is provided on the U-phase power supply conductor 22U, the number of conductors arranged in the radial direction is 1. At the position where the V-phase input terminal 31V is provided on the V-phase power supply conductor 32V and at the position where the W-phase input terminal 41W is provided on the W-phase power supply conductor 42W, the number of conductors arranged in the radial direction is 2. At the position where the neutral conductor 53 is provided, the number of conductors arranged in the radial direction is 2 or 3. At the position where the neutral conductor 54 is provided, the number of conductors arranged in the radial direction is 2 or 3.

[0097] The U-phase power supply conductor 22U has U-phase connection parts 22UC1, 22UC8. The U-phase connection parts 22UC1, 22UC8 are formed to rise from the arc-shaped part of the U-phase power supply conductor 22U and have hook-shaped parts bent radially inward at the tips. As shown in FIG. 8, the U-phase connection parts 22UC1, 22UC8 are arranged outside the resin 81.

[0098] The U-phase power supply side lead wire 23U1 drawn from the U-phase coil 24Up1 is connected to the hook-shaped part of the U-phase connection part 22UC1. The U-phase power supply side lead wire 23U1 is arranged to rise from below between the hook-shaped parts of the U-phase connection part 22UC1, caulked by the hook-shaped parts and further welded to the hook-shaped parts, and held by the hook-shaped parts.

[0099] The U-phase power supply side lead wire 23U8 drawn from the U-phase coil 24Um8 is connected to the hook-shaped part of the U-phase connection part 22UC8. The U-phase power supply side lead wire 23U8 is arranged to rise from below between the hook-shaped parts of the U-phase connection part 22UC8, caulked by the hook-shaped parts and further welded to the hook-shaped parts, and held by the hook-shaped parts.

[0100] The V-phase power supply conductor 32V has V-phase connection parts 32VC4 and 32VC9. The V-phase connection parts 32VC4 and 32VC9 are formed to rise from the arc-shaped part of the V-phase power supply conductor 32V and have hook-shaped parts bent radially inward at the tips. As shown in FIG. 8, the V-phase connection parts 32VC4 and 32VC9 are arranged outside the resin 81.

[0101] The V-phase power supply side lead wire 33V4 drawn from the V-phase coil 34Vm4 is connected to the hook-shaped part of the V-phase connection part 32VC4. The V-phase power supply side lead wire 33V4 is arranged to rise from below between the hook-shaped parts of the V-phase connection part 32VC4, caulked by the hook-shaped part and further welded to the hook-shaped part, and held by the hook-shaped part.

[0102] The V-phase power supply side lead wire 33V9 drawn from the V-phase coil 34Vp9 is connected to the hook-shaped part of the V-phase connection part 32VC9. The V-phase power supply side lead wire 33V9 is arranged to rise from below between the hook-shaped parts of the V-phase connection part 32VC9, caulked by the hook-shaped part and further welded to the hook-shaped part, and held by the hook-shaped part.

[0103] The W-phase power supply conductor 42W has W-phase connection parts 42WC5 and 42WC12. The W-phase connection parts 42WC5 and 42WC12 are formed to rise from the arc-shaped part of the W-phase power supply conductor 42W and have hook-shaped parts bent radially inward at the tips. As shown in FIG. 8, the W-phase connection parts 42WC5 and 42WC12 are arranged outside the resin 81.

[0104] The W-phase power supply side lead wire 43W5 drawn from the W-phase coil 44Wp5 is connected to the hook-shaped part of the W-phase connection part 42WC5. The W-phase power supply side lead wire 43W5 is arranged to rise from below between the hook-shaped parts of the W-phase connection part 42WC5, caulked by the hook-shaped part and further welded to the hook-shaped part, and held by the hook-shaped part.

[0105] The W-phase power supply side lead wire 43W12 drawn from the W-phase coil 44Wm12 is connected to the hook-shaped portion of the W-phase connection portion 42WC12. The W-phase power supply side lead wire 43W12 is arranged to rise from below between the hook-shaped portions of the W-phase connection portion 42WC12, caulked by the hook-shaped portion and further welded to the hook-shaped portion, and held by the hook-shaped portion.

[0106] The neutral conductor 53 has neutral connection portions 53C6, 53C7, 53C10. The neutral connection portions 53C6, 53C7, 53C10 are formed to rise from the arc-shaped portion of the neutral conductor 53 and have hook-shaped portions bent radially inward at the tips. As shown in FIG. 8, the neutral connection portions 53C6, 53C7, 53C10 are arranged outside the resin 81.

[0107] The W-phase neutral point side lead wire 46W6 drawn from the W-phase coil 44Wp6 is connected to the hook-shaped portion of the neutral connection portion 53C6. The W-phase neutral point side lead wire 46W6 is arranged to rise from below between the hook-shaped portions of the neutral connection portion 53C6, caulked by the hook-shaped portion and further welded to the hook-shaped portion, and held by the hook-shaped portion.

[0108] The U-phase neutral point side lead wire 26U7 drawn from the U-phase coil 24Um7 is connected to the hook-shaped portion of the neutral connection portion 53C7. The U-phase neutral point side lead wire 26U7 is arranged to rise from below between the hook-shaped portions of the neutral connection portion 53C7, caulked by the hook-shaped portion and further welded to the hook-shaped portion, and held by the hook-shaped portion.

[0109] The V-phase neutral point side lead wire 36V10 drawn from the V-phase coil 34Vp10 is connected to the hook-shaped portion of the neutral connection portion 53C10. The V-phase neutral point side lead wire 36V10 is arranged to rise from below between the hook-shaped portions of the neutral connection portion 53C10, caulked by the hook-shaped portion and further welded to the hook-shaped portion, and held by the hook-shaped portion.

[0110] The neutral conductor 54 has neutral connection parts 54C2, 54C3, 54C11. The neutral connection parts 54C2, 54C3, 54C11 are formed to rise from the arc-shaped part of the neutral conductor 54 and have hook-shaped parts bent radially inward at their tips. As shown in FIG. 8, the neutral connection parts 54C2, 54C3, 54C11 are arranged outside the resin 81.

[0111] The U-phase neutral-point side lead wire 26U2 drawn from the U-phase coil 24Up2 is connected to the hook-shaped part of the neutral connection part 54C2. The U-phase neutral-point side lead wire 26U2 is arranged to rise from below between the hook-shaped parts of the neutral connection part 54C2, caulked by the hook-shaped part, further welded to the hook-shaped part, and gripped by the hook-shaped part.

[0112] The V-phase neutral-point side lead wire 36V3 drawn from the V-phase coil 34Vm3 is connected to the hook-shaped part of the neutral connection part 54C3. The V-phase neutral-point side lead wire 36V3 is arranged to rise from below between the hook-shaped parts of the neutral connection part 54C3, caulked by the hook-shaped part, further welded to the hook-shaped part, and gripped by the hook-shaped part.

[0113] The W-phase neutral-point side lead wire 46W11 drawn from the W-phase coil 44Wm11 is connected to the hook-shaped part of the neutral connection part 54C11. The W-phase neutral-point side lead wire 46W11 is arranged to rise from below between the hook-shaped parts of the neutral connection part 54C11, caulked by the hook-shaped part, further welded to the hook-shaped part, and gripped by the hook-shaped part.

[0114] The annular bus bar 80 is arranged radially outside the teeth 16 on which each coil 20 is mounted. The annular bus bar 80 is arranged along the yoke part 12. The annular bus bar 80 is arranged to overlap the yoke part 12. The annular bus bar 80 is arranged so as not to protrude radially outside the outer peripheral surface of the yoke part 12, thereby avoiding an increase in the radial size of the stator 4.

[0115] When the neutral conductors 53 and 54 are formed by windings, the neutral conductors 53 and 54 may be arranged on the radially outer side of the teeth 16, similarly to the annular bus bar 80. Alternatively, the neutral conductors 53 and 54 may be arranged at the coil ends.

[0116] Grooves for arranging the respective lead wires may be formed in the first flange portion 72 of the bobbin 70 shown in FIG. 4. Each power supply side lead wire and each neutral point side lead wire are arranged through the grooves and can extend from the position of the yoke portion 12 of the stator core 10 in the radial direction to the position of the teeth 16.

[0117] In FIG. 5, the neutral point 51 is shown in the vicinity of the W-phase coil 44Wp6, and the neutral point 52 is shown in the vicinity of the W-phase coil 44Wm11. However, the arrangement of the neutral points 51 and 52 is not limited. The neutral points 51 and 52 may be arranged at any position as long as the U-phase, V-phase, and W-phase are connected at one location.

[0118] It is desirable that the neutral conductor 53 and the neutral conductor 54 are configured as separate members and are not electrically connected to each other. When the neutral conductor 53 and the neutral conductor 54 are connected, for example, when a potential difference of the line voltage occurs between the V-phase neutral point side lead wire 36V10 and the W-phase neutral point side lead wire 46W11, a current flows between the neutral point 51 and the neutral point 52, and a current (circulating current) flows through the coil 20 connected to the neutral point 52. Since this circulating current becomes a loss and the efficiency of the electric motor 1 decreases, it is desirable that the neutral conductors 53 and 54 are separate members.

[0119] FIG. 9 is a wiring diagram of another example of the stator 4. In the following description of FIG. 9, the description of the same configuration as that of FIG. 5 will be omitted, and the description will focus on the configuration specific to FIG. 9 that is different from FIG. 5.

[0120] In the example shown in FIG. 5, for the coil 20 of each phase, the neutral point side lead wire of each phase extends on the side where the power supply side lead wire of each phase extends. On the other hand, in FIG. 9, for the coil 20 of each phase, the neutral point side lead wire of each phase extends on the side opposite to the side where the power supply side lead wire of each phase extends. In the case of the example shown in FIG. 9, the neutral conductors 53, 54 and the neutral points 51, 52 may be arranged at the coil ends or may be arranged radially inward of the teeth 16.

[0121] In the electric motor 1 of the embodiment described above, as shown in FIGS. 2 and 3, the number of poles of the rotor 3 is 2 poles, and the number of teeth 16 is 12. As shown in FIG. 4, the windings are wound around the teeth 16 in concentrated winding to form the coils 20. As shown in FIGS. 2, 3, and 5, two adjacent teeth 1601, 1602 in the circumferential direction constitute the tooth portion 171, and the windings of the U-phase are connected in series to the tooth portion 171 and wound in the same direction. The teeth 16 are arranged such that adjacent tooth portions have different phases and the phases of the three phases are arranged in order in the circumferential direction.

[0122] By winding the windings around the teeth 16 in concentrated winding to form the coils 20, connecting the windings of the same phase in series and winding them in the same direction around the adjacent teeth 16 in the circumferential direction, and arranging the adjacent tooth portions to have different phases and the phases of the three phases to be arranged in order in the circumferential direction, an electric motor 1 with a 2-pole 12-slot configuration that is simple in structure and small in size can be realized. Since the number of poles is the minimum 2 poles, the electric motor 1 can rotate at high speed.

[0123] The windings forming the coil 20 are separated from the teeth 16 around which the windings are wound as the winding progresses from the start to the end of the winding around the teeth 16. By defining the start and end positions of the winding of the coil 20, the positions of the lead wires connected to the power supply conductors or neutral conductors of each phase can be determined, and the positions of the insulating tubes for insulating each lead wire can be determined.

[0124] The two series-connected windings of the same phase are connected in series, and the voltage applied to the electric motor 1 is divided into two coils 20. Therefore, the potential difference between adjacent coils 20 of the same phase is halved. By reducing the potential difference (in-phase potential difference) across the films of adjacent coils 20, the withstand voltage stress on the insulating materials such as the film of the coil 20 and the bobbin 70 can be reduced. Therefore, it is possible to ensure insulation with a standard magnet wire.

[0125] Compared with a 6-slot electric motor generally selected when having two poles, in the 12-slot electric motor 1 of the embodiment, the demagnetizing field from the stator 4 is dispersed to two teeth 16, thereby reducing the magnetic flux variation with respect to the magnet and suppressing the heat generation of the magnet. The skewing effect due to the windings of the stator 4 is realized, and the torque ripple can be reduced. By increasing the contact area between the coil 20 and the stator core 10 and increasing the heat transfer amount, the coil 20 can be effectively cooled.

[0126] As shown in FIGS. 2, 3, and 5, the V-phase winding is wound around the tooth portion 172 adjacent to the tooth portion 171 where the U-phase coil is mounted, and two V-phase coils 34Vm3 and 34Vm4 are formed. A U-phase neutral point side lead wire 26U2 is drawn from the U-phase coil 24Up2 toward the neutral point 52. A V-phase neutral point side lead wire 36V3 is drawn from the V-phase coil 34Vm3 toward the neutral point 52. The tooth 1602 where the U-phase coil 24Up2 is mounted and the tooth 1603 where the V-phase coil 34Vm3 is mounted are adjacent to each other.

[0127] Since both the U-phase coil 24Up2 and the V-phase coil 34Vm3 are connected to the neutral point 52, the potential difference between the U-phase coil 24Up2 and the V-phase coil 34Vm3 is reduced to a level where insulation is not required. By arranging the U-phase coil 24Up2 and the V-phase coil 34Vm3 adjacent to each other, the inter-phase insulation between the U-phase coil 24Up2 and the V-phase coil 34Vm3 can be made unnecessary. Since it is possible to reduce the number of locations where inter-phase insulation is required in the stator 4 to three, the configuration of the stator 4 can be simplified and the manufacturing cost can be reduced.

[0128] For the electric motor 1 having a two-pole and twelve-slot configuration, among the two U-phase coils 24Up1 and 24Up2 connected in series, it is necessary to place the U-phase coil 24Up1 on the upstream side of the current flow and the U-phase coil 24Up2 on the downstream side. Among the two V-phase coils 34Vm3 and 34Vm4 connected in series adjacent to the U-phase coils 24Up1 and 24Up2, it is necessary to place the V-phase coil 34Vm4 on the upstream side of the current flow and the V-phase coil 34Vm3 on the downstream side. As a result, the U-phase coil 24Up2 and the V-phase coil 34Vm3 will be adjacent to each other, eliminating the need for insulation between the U-phase coil 24Up2 and the V-phase coil 34Vm3.

[0129] The V-phase coil 34Vp10 shown in FIG. 5 is connected to the neutral point 51, and the adjacent W-phase coil 44Wm11 is connected to the neutral point 52. Since the potentials of both the neutral point 51 and the neutral point 52 are zero and equal, the potential difference between the V-phase coil 34Vp10 and the W-phase coil 44Wm11 is also reduced to a level where insulation is not required. Therefore, insulation between the V-phase coil 34Vp10 and the W-phase coil 44Wm11 can also be eliminated, and only three locations where phase insulation is required can be provided in the stator 4.

[0130] As shown in FIGS. 2, 3, and 5, a W-phase winding is wound around the tooth portion 176 adjacent to and on the opposite side of the tooth portion 172 where the V-phase coils 34Vm3 and 34Vm4 are mounted, with respect to the tooth portion 171 where the U-phase coils are mounted, to form the W-phase coil 44Wm12. An interphase insulation paper 61 is disposed between the U-phase winding forming the U-phase coil 24Up1 and the W-phase winding forming the W-phase coil 44Wm12. The interphase insulation paper 61 insulates the U-phase winding forming the U-phase coil 24Up1 and the W-phase winding forming the W-phase coil 44Wm12.

[0131] A U-phase power supply side lead wire 23U1 connected to a U-phase input terminal 21U is drawn out from a U-phase coil 24Up1. A W-phase power supply side lead wire 43W12 connected to a W-phase input terminal 41W is drawn out from a W-phase coil 44Wm12. A potential difference may occur between the adjacent U-phase coil 24Up1 and W-phase coil 44Wm12. By disposing an inter-phase insulating paper 61 between the U-phase coil 24Up1 and the W-phase coil 44Wm12, the U-phase coil 24Up1 and the W-phase coil 44Wm12 can be surely insulated from each other.

[0132] As shown in FIG. 5, the electric motor 1 further includes a U-phase power supply conductor 22U, a V-phase power supply conductor 32V, a W-phase power supply conductor 42W, and neutral conductors 53, 54. The U-phase power supply conductor 22U constitutes a power supply path to the U-phase coils 24Up1, 24Up2. The V-phase power supply conductor 32V constitutes a power supply path to the V-phase coils 34Vm3, 34Vm4. The W-phase power supply conductor 42W constitutes a power supply path to the W-phase coils 44Wm11, 44Wm12. The neutral conductor 54 electrically connects the U-phase coils 24Up1, 24Up2 to the neutral point 52, electrically connects the V-phase coils 34Vm3, 34Vm4 to the neutral point 52, and electrically connects the W-phase coils 44Wm11, 44Wm12 to the neutral point 52. As shown in FIGS. 6 and 7, the U-phase power supply conductor 22U, the V-phase power supply conductor 32V, the W-phase power supply conductor 42W, and the neutral conductors 53, 54 each have an arc shape. As shown in FIG. 8, the three-phase power supply conductors 22U, 32V, 42W and the neutral conductors 53, 54 are positioned by an annular resin 81. The number of the U-phase power supply conductor 22U, the V-phase power supply conductor 32V, the W-phase power supply conductor 42W, and the neutral conductors 53, 54 arranged in the radial direction is 3 or less.

[0133] Among the U-phase power supply conductor 22U, the V-phase power supply conductor 32V, the W-phase power supply conductor 42W, and the neutral conductors 53, 54, the number of conductors at the same position in the circumferential direction arranged in the radial direction is 3 or less at any position in the circumferential direction. Thereby, the arrangement space of the conductors can be reduced, and the stator 4 can be miniaturized. In addition, the locations that require insulation between the conductors can be reduced.

[0134] As shown in FIGS. 6 and 7, the V-phase power supply conductor 32V has a first portion 32V1 disposed radially outside the U-phase power supply conductor 22U and a second portion 32V2 disposed radially inside the W-phase power supply conductor 42W.

[0135] In this way, a configuration can be realized in which the number of the U-phase power supply conductor 22U, the V-phase power supply conductor 32V, the W-phase power supply conductor 42W, and the neutral conductors 53 and 54 arranged in the radial direction is 3 or less, and an increase in the size of the stator 4 in the radial direction can be avoided.

[0136] Although the embodiments have been described as above, it should be considered that all the embodiments disclosed this time are illustrative in all respects and not restrictive. The scope of the present invention is shown not by the above description but by the claims, and it is intended that all meanings equivalent to the claims and all changes within the scope are included.

Explanation of Reference Numerals

[0137] 1 Electric motor, 2 Rotating shaft, 3 Rotor, 3N N - pole core part, 3S S - pole core part, 10 Stator core, 12 Yoke part, 16, 1601 - 1612 Teeth, 18, 1801 - 1812 Slots, 20 Coil, 21U U - phase input terminal, 22U U - phase power supply conductor, 22UC1, 22UC8 U - phase connection part, 23U1, 23U8 U - phase power supply side lead wire, 24Um7, 24Um8, 24Up1, 24Up2 U - phase coil, 25U12, 25U78 U - phase cross - conductor, 26U2, 26U7 U - phase neutral point side lead wire, 31V V - phase input terminal, 32V V - phase power supply conductor, 32V1 First part, 32V2 Second part, 32VC4, 32VC9 V - phase connection part, 33V4, 33V9 V - phase power supply side lead wire, 34Vm3, 34Vm4, 34Vp9, 34Vp10 V - phase coil, 35V34, 35V910 V - phase cross - conductor, 36V3, 36V10 V - phase neutral point side lead wire, 41W W - phase input terminal, 42W W - phase power supply conductor, 42WC5, 42WC12 W - phase connection part, 43W5, 43W12 W - phase power supply side lead wire, 44Wm11, 44Wm12, 44Wp5, 44Wp6 W - phase coil, 45W1112, 45W56 W - phase cross - conductor, 46W6, 46W11 U - phase neutral point side lead wire, 51, 52 Neutral points, 53, 54 Neutral conductors, 53C6, 53C7, 53C10, 54C2, 54C3, 54C11 Neutral connection parts, 61, 62, 63 Phase - to - phase insulation paper, 70 Bobbin, 71 Winding part, 72 First flange part, 73 Second flange part, 80 Annular busbar, 81 Resin, 110 Electric compressor, 171 - 176 Tooth parts.

Claims

1. A stator comprising a cylindrical yoke portion and twelve teeth protruding radially inward from the yoke portion, and a three-phase coil in which windings are wound around the teeth in concentrated winding, a rotor having two poles and being rotatable relative to the stator, wherein the teeth are wound such that two circumferentially adjacent teeth are used as a tooth portion, and the windings of the same phase are connected in series to the tooth portion in the same direction and with the same current direction, and the teeth are arranged such that adjacent tooth portions have different phases and each of the three phases is arranged in order in the circumferential direction, a rotating electrical machine.

2. The three-phase coils are arranged such that the coils of the first phase, the coils of the second phase, and the coils of the third phase are arranged in order with respect to six tooth portions arranged in the circumferential direction, the coils of the second phase are mounted on the tooth portion adjacent to the tooth portion on which the coils of the first phase are mounted, a first-phase lead wire is drawn from one of the windings of the coils of the first phase toward the neutral point, and a second-phase lead wire is drawn from one of the windings of the coils of the second phase toward the neutral point, and the winding forming the coils of the first phase from which the first-phase lead wire is drawn and the winding forming the coils of the second phase from which the second-phase lead wire is drawn are each wound around two circumferentially adjacent teeth, the rotating electrical machine according to claim 1.

3. the coils of the third phase are mounted on the tooth portion adjacent to the opposite side of the tooth portion on which the coils of the second phase are mounted with respect to the tooth portion on which the coils of the first phase are mounted, the stator further includes a phase insulation body disposed between the winding forming the coils of the first phase and the winding forming the coils of the third phase and insulating the winding forming the coils of the first phase and the winding forming the coils of the third phase, the rotating electrical machine according to claim 2.

4. three-phase power supply conductors constituting a power supply path to the three-phase coils, and a neutral conductor electrically connecting the three-phase coils and the neutral point. The three-phase power supply conductors and the neutral conductor are arranged along the yoke portion and each have an arc shape, the three-phase power supply conductors and the neutral conductor are positioned by an annular resin, and the number of the three-phase power supply conductors and the neutral conductor arranged in the radial direction is 3 or less. The rotating electrical machine according to any one of claims 1 to 3.

5. The three-phase power supply conductors include a first-phase power supply conductor, a second-phase power supply conductor, and a third-phase power supply conductor. The second-phase power supply conductor has a first portion arranged outside the first-phase power supply conductor in the radial direction and a second portion arranged inside the third-phase power supply conductor in the radial direction. The rotating electrical machine according to claim 4.

6. A stator core including a cylindrical yoke portion and twelve teeth protruding radially inward from the yoke portion, and a three-phase coil in which windings are wound around the teeth in concentrated winding. A rotor having 2 poles and being rotatable relative to the stator. Two adjacent teeth in the circumferential direction are defined as a tooth portion, and windings of the same phase are connected in series to the tooth portion and wound in the same direction. The teeth are arranged such that adjacent tooth portions have different phases and each of the three phases is arranged in order in the circumferential direction. The rotating electrical machine further includes a jumper conductor that connects the end portion where winding ends of the winding wound around one of the two circumferentially adjacent teeth constituting the tooth portion and the start portion where winding starts of the winding wound around the other of the two circumferentially adjacent teeth constituting the tooth portion.

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