stata

Abstract

To provide a stator that can suppress the generation of circulating current even when the effective number of turns is not an integer, thereby improving productivity and reducing manufacturing costs. [Solution] In the stator of the present disclosure, at one end of the stator core, the tips of two legs protruding from one 2·i layer and the other 2·i-1 layer on one side in the circumferential direction of the first and second slots spaced five slots apart are joined together, and the tips of two legs protruding from one 2·i layer and the other 2·i+1 layer on one side in the circumferential direction of the first and second slots spaced five slots apart are joined together so that the winding end of the 2·i layer and the winding start of the 2·i+1 layer are connected.

Description

Technical Field

[0001] The present disclosure relates to a stator including a stator core including a plurality of slots and a plurality of stator coils wound around the stator core.

Background Art

[0002] Conventionally, a stator is known that includes a stator core having a plurality of slots arranged in the circumferential direction, and three-phase (U-phase, V-phase, W-phase) stator coils wound around the stator core (see, for example, Patent Document 1). In this stator, the three-phase stator coils each include a multiple of four parallel windings (parallel coils) connected in parallel, and are connected by a Y-connection. Each parallel winding is formed by inserting a pair of straight portions (legs) of a plurality of U-shaped conductor segments (segment coils) into corresponding slots so as to protrude from one end (twisted side) in the axial direction of the stator core, and twisting each straight portion in the circumferential direction to join the tips of two corresponding straight portions. In other words, the multiple conductor segments include a first conductor segment having a pair of linear sections that are inserted into two first slots spaced five slots apart, a second conductor segment having a pair of linear sections that are inserted into two second slots spaced seven slots apart on either side of the first slot, and a third conductor segment having a pair of linear sections that are inserted into predetermined first and second slots spaced six slots apart. The pair of linear sections of the first conductor segment are inserted into one 2·i-1 layer (where i=3,2,1 in the example of Patent Document 1) and the other 2·i layer on one side (winding start side) of the two first slots in the circumferential direction. The pair of linear sections of the second conductor segment are inserted into one 2·i-1 layer and the other 2·i layer on one side of the two second slots in the circumferential direction, such that the second conductor segment straddles the corresponding first conductor segment. Furthermore, a pair of legs of the third conductor segment are inserted into one 2·i layer and the other 2·i+1 layer on one side of predetermined first and second slots spaced six slots apart in the circumferential direction, forming a jumper wire (57) that spans between the 2·i layer and the 2·i+1 layer at the other end of the stator core (opposite the twisted side). Also, at one end of the stator core, two legs protruding from one 2·i layer and the other 2·i-1 layer on one side of two slots spaced six slots apart in the circumferential direction are twisted together so that their ends are joined.As a result, in each parallel winding, the linear portions of the conductor segments are evenly distributed in both the first and second slots adjacent to each other in the circumferential direction. This eliminates the timing difference in the generation of induced voltages at each magnetic pole of the parallel winding in response to the passage of the rotor's magnets, thereby preventing the generation of circulating currents in each parallel winding.

[0003] Furthermore, a ring-aligning device for segment coils is known that aligns multiple segment coils, each having first and second ends (legs) connected to one another via bent or curved portions, in a ring shape (see, for example, Patent Document 2). This ring-aligning device includes an aligning ring section, a segment coil insertion section, and a coil guiding section. The aligning ring section includes storage grooves that open in one direction of the cylindrical axis along the outer circumference of a cylindrical shape and are arranged at a predetermined pitch, and that rotatably support the segment coils with the first end as the pivot axis, and performs a ring-rotation movement about the cylindrical axis. The segment coil insertion section inserts the first end of a segment coil into at least one storage groove following the rearmost storage groove into which the first end is inserted, in accordance with the ring-rotation movement of the aligning ring section. The coil guiding section guides the second end of a segment coil, whose first end is inserted into a storage groove, to a storage groove different from the storage groove into which the first end of the segment coil is inserted, in accordance with the ring-rotation movement of the aligning ring section. In this annular alignment device, the insertion of the first end of the segment coil into the storage groove and the guidance of the second end of the segment coil into the storage groove are performed simultaneously in accordance with the annular rotational movement of the alignment annular section. This makes it possible to align multiple segment coils in an annular shape by aligning the inclination direction of the bent or curved portions of the stator core with respect to the radial direction, while shortening the working time. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 5896250 (Figures 13A-15) [Patent Document 2] Patent No. 3975891 [Overview of the Initiative] [Problems that the invention aims to solve]

[0005] In a rotating electric machine including a stator as described in Patent Document 1, the output characteristics change depending on the number of turns (hereinafter referred to as "effective number of turns") obtained by dividing the number of linear sections (number of layers) in one slot by the number of parallel windings (number of parallel connections), and the mounting target of the rotating electric machine may require a stator with a non-integer number of turns (for example, 1.5 or 2.5). Furthermore, according to the stator described in Patent Document 1, even if the effective number of turns is a non-integer, it is possible to prevent the generation of circulating current between multiple parallel windings. However, in the stator described in Patent Document 1, the inclination direction with respect to the radial direction of the stator core of the part connecting the pair of legs of the third conductor segment (the part forming the jumper wire) is in the opposite direction to that of the first and second conductor segments, so it is not possible to arrange the first to third conductor segments in a ring shape using a ring arrangement device as described in Patent Document 2. For this reason, it becomes necessary to assemble the third conductor segment to the stator using a multi-axis robot or the like, which leads to a decrease in stator productivity and an increase in manufacturing costs.

[0006] Therefore, the primary objective of this disclosure is to provide a stator that can suppress the generation of circulating current even when the effective number of turns is not an integer, thereby improving productivity and reducing manufacturing costs. [Means for solving the problem]

[0007] The stator of this disclosure includes a stator core including a plurality of slots formed circumferentially spaced apart so as to extend radially, and a plurality of segment coils having pairs of legs inserted into different slots and forming a plurality of stator coils by electrical connections between the tips of the corresponding legs. In such a stator, when the number of poles is "p" and the number of slots is "n", n = 6·p. Each plurality of stator coils includes 4·m parallel coils (where "m" is an integer of 1 or more) connected in parallel. An even number of legs are inserted radially into one slot. The plurality of segment coils include a first segment coil, a second segment coil, and a third segment coil. A pair of legs of the first segment coil are inserted so as to protrude from one end of the stator core into one 2·i-1 layer (where "i" is an integer of 1 or more, i=1,...,imax) on one side of two first slots spaced 6 slots apart in the circumferential direction and into the other 2·i layer. A pair of legs of the second segment coil are inserted so as to protrude from one end of the stator core into one 2·i-1 layer and the other 2·i layer on one side of two second slots spaced eight slots apart on both sides of the first slot, and the second segment coil straddles the corresponding first segment coil. A pair of legs of the third segment coil are inserted so as to protrude from one end of the stator core into one 2·i-1 layer and the other 2·i layer on one side of predetermined first and second slots spaced seven slots apart, and the third segment coil forms the winding start in the 2·i+1 layer. At one end of the stator core, two legs protruding from one 2·i layer and the other 2·i-1 layer on one side of first and second slots spaced five slots apart are twisted so that their ends are joined together. Furthermore, at one end of the stator core, two legs protruding from one 2·i layer and the other 2·i+1 layer on one side of the circumferential direction of the first and second slots, which are spaced five slots apart, are twisted together so that the winding end of the 2·i layer and the winding start of the 2·i+1 layer are connected, and their tips are joined together.

[0008] In other words, each parallel coil is basically formed by inserting a second segment coil into two second slots spaced eight slots apart, straddling a first segment coil inserted into two first slots spaced six slots apart, and then joining the corresponding legs at one end of the stator core at a five-slot pitch. This makes it possible to cancel out the circulating current generated by the timing difference in the induced voltage generated at each magnetic pole of the parallel coil in response to the passage of the rotor's magnets, even if the effective number of turns is not an integer, within each parallel winding, thereby suppressing the flow of circulating current in the stator coil. Furthermore, in the stator of this disclosure, the legs of the first to third segment coils forming one phase of the stator coil are inserted into every three adjacent slots in the circumferential direction, and each of the multiple stator coils is wound around the stator core by short-section winding. As a result, a rotating electric machine including this stator can achieve higher output and reduce vibration and noise compared to a rotating electric machine including a stator in which the stator coil is wound around the stator core by full-section winding. In addition, this stator eliminates the need for skew and other measures to reduce torque ripple. Furthermore, in the stator of this disclosure, the inclination direction of the portion connecting the pair of legs of the third segment coil (jumper wire portion) with respect to the radial direction of the stator core is the same as that of the first and second segment coils. This makes it possible to assemble the first to third segment coils wound around the 2·i-1 and 2·i layers into the stator core after arranging them in a ring shape using a well-known ring arrangement device. This allows for a reduction in cycle time and cost reduction by eliminating the need for multi-axis robots, etc. As a result, the stator of this disclosure suppresses the generation of circulating current even when the effective number of turns is not an integer, and improves productivity, thereby reducing manufacturing costs.

[0009] Other stators in this disclosure include a stator core comprising a plurality of slots formed circumferentially spaced so as to extend radially, and a plurality of segment coils, each having a pair of legs inserted into different slots, and forming a plurality of stator coils by electrical connections between the tips of the corresponding legs. In such a stator, when the number of poles is "p" and the number of slots is "n", n = 6·p. Each plurality of stator coils comprises 4·m parallel coils (where "m" is an integer of 1 or more) connected in parallel. An even number of legs are inserted radially into a single slot. The plurality of segment coils comprises a first segment coil, a second segment coil, and a third segment coil. A pair of legs of the first segment coil are inserted so as to protrude from one end of the stator core into one 2·i-1 layer (where "i" is an integer of 1 or more, i=1,...,imax) on one side of two first slots spaced 4 slots apart, and into the other 2·i layer. A pair of legs of the second segment coil are inserted so as to protrude from one end of the stator core into one 2·i-1 layer and the other 2·i layer on one side of two second slots spaced six slots apart on both sides of the first slot, and the second segment coil straddles the corresponding first segment coil. A pair of legs of the third segment coil are inserted so as to protrude from one end of the stator core into one 2·i-1 layer and the other 2·i layer on one side of predetermined first and second slots spaced five slots apart, and the third segment coil forms the winding start in the 2·i+1 layer. At one end of the stator core, two legs protruding from one 2·i layer and the other 2·i-1 layer on one side of first and second slots spaced seven slots apart are twisted together so that their ends are joined. Furthermore, at one end of the stator core, two legs protruding from one 2·i layer and the other 2·i+1 layer on one side of the circumferential direction of the first and second slots, which are spaced 7 slots apart, are twisted together so that the winding end of the 2·i layer and the winding start of the 2·i+1 layer are connected, and their tips are joined together.

[0010] In other words, each parallel coil is basically formed by inserting a second segment coil into two second slots spaced six slots apart, so as to straddle a first segment coil inserted into two first slots spaced four slots apart, and joining the corresponding legs at one end of the stator core at a seven-slot pitch. This makes it possible to cancel out the circulating current generated by the timing difference in the generation of induced voltages at each magnetic pole of the parallel coil in response to the passage of the rotor magnets within each parallel winding, even if the effective number of turns is not an integer, thereby suppressing the flow of circulating current in the stator coil. In addition, in other stators of this disclosure, the legs of the first to third segment coils forming a single-phase stator coil are inserted into every three adjacent slots in the circumferential direction, and each of the multiple stator coils is wound around the stator core by short-section winding. As a result, in a rotating electric machine including this stator, it is possible to increase the output and reduce vibration and noise compared to a rotating electric machine including a stator in which the stator coils are wound around the stator core by full-section winding. In addition, this stator eliminates the need for skew and other measures to reduce torque ripple. Furthermore, in the stator of this disclosure, the inclination direction of the portion connecting the pair of legs of the third segment coil (jumper wire portion) with respect to the radial direction of the stator core is the same as that of the first and second segment coils. This makes it possible to assemble the first to third segment coils wound around the 2·i-1 and 2·i layers into the stator core after arranging them in a ring shape using a well-known ring arrangement device. This allows for a reduction in cycle time and cost reduction by eliminating the need for multi-axis robots, etc. As a result, the stator of this disclosure suppresses the generation of circulating current even when the effective number of turns is not an integer, and improves productivity, thereby reducing manufacturing costs. [Brief explanation of the drawing]

[0011] [Figure 1] This is a perspective view showing the status of this disclosure. [Figure 2] This is a schematic diagram showing an example of a stator coil of the stator described herein. [Figure 3]This is a schematic diagram showing the segment coils that form the stator coil of the stator of the present disclosure. [Figure 4] This is an explanatory diagram illustrating an example of how the segment coils are assembled to the stator core of the stator according to the present disclosure. [Figure 5] This is a perspective view showing an assembly of segment coils. [Figure 6] This is a perspective view showing the assembly procedure for the segment coil assembly to the stator core. [Figure 7] This is an enlarged perspective view showing the essential parts of the stator of this disclosure. [Figure 8] This is a schematic diagram showing other stator coils applicable to the stator of this disclosure. [Figure 9] This is an explanatory diagram illustrating another configuration of the segment coils to the stator core of the stator of the present disclosure. [Modes for carrying out the invention]

[0012] Next, with reference to the drawings, embodiments for carrying out the invention of this disclosure will be described.

[0013] Figure 1 is a perspective view showing the stator 1 of this disclosure. The stator 1 shown in the figure, together with a rotor (not shown), constitutes a three-phase AC motor (rotating electric machine) used, for example, as a driving source or generator for electric vehicles or hybrid vehicles. In this embodiment, the stator 1 includes an annular stator core 2, a stator coil 3u (U-phase coil), a stator coil 3v (V-phase coil), and a stator coil 3w (W-phase coil).

[0014] The stator core 2 of the stator 1 is formed in an annular shape by, for example, stacking multiple electromagnetic steel sheets formed in a substantially annular shape by press working and connecting them in the stacking direction, or by, for example, press-molding and sintering ferromagnetic powder. As shown in Figure 1, the stator core 2 includes a central hole 2o in which the rotor is arranged, a plurality of teeth portions 2t that extend radially from the annular outer circumference (yoke portion) toward the axis and are adjacent to each other at a certain interval in the circumferential direction, and a plurality of slots 20 (for example, 48 in this embodiment) formed between adjacent teeth portions 2t. Each of the plurality of slots 20 extends radially from the stator core 2 and is arranged circumferentially at a certain interval, opening through the central hole 2o. In addition, an insulator (insulating paper), not shown, is placed inside each slot 20. Furthermore, the stator 1 has the same number of magnetic poles as the rotor (eight in this embodiment), and when the number of magnetic poles (number of poles) of the stator 1 is "p" and the number of slots 20 is "n", the relationship n = 6·p holds.

[0015] The stator coils 3u, 3v, and 3w are each formed by electrically joining multiple segment coils (coil wires) 4. As shown in Figure 2, the stator coil 3u includes four parallel coils U1, U2, U3, and U4 that are electrically connected in parallel. The stator coil 3v includes four parallel coils V1, V2, V3, and V4 that are electrically connected in parallel with each other, and the stator coil 3w includes four parallel coils W1, W2, W3, and W4 that are electrically connected in parallel with each other. The stator coils 3u, 3v, and 3w are then connected to each other by a star connection (Y connection), as shown in Figure 2. That is, the parallel coils U1-U4, V1-V4, and W1-W4 are connected to each other by a so-called 4Y connection.

[0016] The segment coil 4 is an electric conductor formed by bending a rectangular wire, for example, with an insulating coating made of enamel resin, in the flatwise direction and the edgewise direction. In the present embodiment, as shown in FIG. 3, the segment coil 4 includes a first segment coil 4a, a second segment coil 4b, and a third segment coil 4c. The first to third segment coils 4a, 4b, 4c are formed in a substantially U shape, and each has a pair (two) of leg portions 40 and a connecting wire portion 41 connecting the pair of leg portions 40. Further, a crank portion 42 is formed in the connecting wire portion 41 of the first to third segment coils 4a, 4b, 4c so as to extend obliquely between two flatwise bending portions. The two leg portions 40 of the first to third segment coils 4a, 4b, 4c are inserted into different slots 20 from the other end side of the stator core 2 so as to protrude from one end (the upper end in FIG. 1) of the stator core 2, and the connecting wire portions 41 of the first to third segment coils 4a, 4b, 4c are aligned on the other end side of the stator core 2.

[0017] In the present embodiment, the first to third segment coils 4a, 4b, 4c are assembled to the stator core 2 such that an even number (six in the present embodiment) of leg portions 40 protrude radially adjacent to each other from each of the plurality of slots 20, and a plurality of layers are formed by the plurality of leg portions 40 protruding from each of the plurality of slots 20 and adjacent to each other in the circumferential direction of the stator core 2. Hereinafter, the layer of the plurality of leg portions 40 (tip portions) adjacent to each other in the circumferential direction on the outermost peripheral side of the stator core 2 is referred to as the "first layer", the radially inner layers are sequentially referred to as the "second layer", the "third layer",..., and the layer of the plurality of leg portions 40 adjacent to each other in the circumferential direction on the innermost peripheral side is referred to as the "sixth layer". The number of "layers" in the stator 1 corresponds to the number of leg portions 40 arranged in each slot 20.

[0018] Next, while referring to FIG. 4, taking the stator coil 3u as an example, the assembly mode of the first to third segment coils 4a, 4b, 4c with respect to the stator core 2 will be described. As shown in FIG. 4, a pair of legs 40 (refer to the circled marks in FIG. 4) of the first segment coil 4a are inserted from one end side (front side of the paper surface in FIG. 4) of the stator core 2 so as to protrude from one end (back side of the paper surface in FIG. 4) of the stator core 2 into one of the 2·i - 1 layers (where "i" is an integer greater than or equal to 1, i = 1, …, imax (in this embodiment, imax = 3)) and the other 2·i layers on one side (start winding side) in the circumferential direction of two first slots 21 separated by 6 slots.

[0019] More specifically, a pair of legs 40 of the first segment coil 4a forming the parallel coil U1 of the stator coil 3u are inserted into the first layer of slot 18 and the second layer of slot 24, the first layer of slot 42 and the second layer of slot 48, the third layer of slot 30 and the fourth layer of slot 36, the fifth layer of slot 18 and the sixth layer of slot 24, and the fifth layer of slot 42 and the sixth layer of slot 48 as shown in FIG. 4. Also, a pair of legs 40 of the first segment coil 4a forming the parallel coil U2 are inserted into the first layer of slot 6 and the second layer of slot 12, the first layer of slot 30 and the second layer of slot 36, the third layer of slot 18 and the fourth layer of slot 24, the third layer of slot 42 and the fourth layer of slot 48, and the fifth layer of slot 30 and the sixth layer of slot 36 as shown in FIG. 4.

[0020] Furthermore, as shown in Figure 4, the pair of legs 40 of the first segment coil 4a forming the parallel coil U3 are inserted into the first layer of slot 24 and the second layer of slot 30, the first layer of slot 48 and the second layer of slot 6, the third layer of slot 36 and the fourth layer of slot 42, the fifth layer of slot 24 and the sixth layer of slot 30, and the fifth layer of slot 48 and the sixth layer of slot 6. Also, as shown in Figure 4, the pair of legs 40 of the first segment coil 4a forming the parallel coil U4 are inserted into the first layer of slot 12 and the second layer of slot 18, the first layer of slot 36 and the second layer of slot 42, the third layer of slot 24 and the fourth layer of slot 30, the third layer of slot 48 and the fourth layer of slot 6, and the fifth layer of slot 36 and the sixth layer of slot 42.

[0021] The pair of legs 40 of the second segment coil 4b (see circles in Figure 4) are inserted from the other end of the stator core 2 so as to protrude from one end of the stator core 2 into one 2·i-1 layer and the other 2·i layer on one side (winding start side) of two second slots 22 spaced 8 slots apart on both sides of the first slot 21, and the jumper wires 41 of the second segment coil 4b straddle the jumper wires 41 of the corresponding first segment coil 4a (see Figure 1). More specifically, the pair of legs 40 of the second segment coil 4b forming the parallel coil U1 of the stator coil 3u are inserted into the first layer of slot 5 and the second layer of slot 13, the first layer of slot 9 and the second layer of slot 37, the third layer of slot 17 and the fourth layer of slot 25, the third layer of slot 41 and the fourth layer of slot 1, and the fifth layer of slot 29 and the sixth layer of slot 37, as shown in Figure 4. Furthermore, as shown in Figure 4, the pair of legs 40 of the second segment coil 4b forming the parallel coil U2 are inserted into the first layer of slot 17 and the second layer of slot 25, the first layer of slot 41 and the second layer of slot 1, the third layer of slot 29 and the fourth layer of slot 37, the fifth layer of slot 17 and the sixth layer of slot 25, and the fifth layer of slot 41 and the sixth layer of slot 1.

[0022] Furthermore, as shown in Figure 4, the pair of legs 40 of the second segment coil 4b forming the parallel coil U3 are inserted into the first layer of slot 11 and the second layer of slot 19, the first layer of slot 35 and the second layer of slot 43, the third layer of slot 23 and the fourth layer of slot 31, the third layer of slot 47 and the fourth layer of slot 7, and the fifth layer of slot 35 and the sixth layer of slot 43. Also, as shown in Figure 4, the pair of legs 40 of the second segment coil 4b forming the parallel coil U4 are inserted into the first layer of slot 23 and the second layer of slot 31, the first layer of slot 47 and the second layer of slot 7, the third layer of slot 35 and the fourth layer of slot 43, the fifth layer of slot 23 and the sixth layer of slot 31, and the fifth layer of slot 47 and the sixth layer of slot 7.

[0023] The pair of legs 40 of the third segment coil 4c (see circles in Figure 4) are inserted from the other end of the stator core 2 so as to protrude from one end of the stator core 2 into one 2·i+1 (=2·(i+1)-1) layer and the other 2·(i+1) layer on one side (winding start side) of predetermined first and second slots 21 and 22 that are spaced 7 slots apart in the circumferential direction, and one of the pair of legs 40 forms the winding start portion in the 2·i+1 layer. That is, the parallel coil U1 of the stator coil 3u includes two third segment coils 4c. The pair of legs 40 of one of the third segment coils 4c of the parallel coil U1 are inserted into the third layer of slot 5 and the fourth layer of slot 12, as shown in Figure 4, forming the winding start portion in the third layer (2·i+1 layer). The pair of legs 40 of the other third-segment coil 4c of the parallel coil U1 are inserted into the fifth layer of the sixth slot and the sixth layer of the thirteenth slot, as shown in Figure 4, forming the starting point of the winding in the fifth layer (2·i+1 layer).

[0024] The parallel coil U2 of the stator coil 3u includes two third-segment coils 4c. A pair of legs 40 of one of the third-segment coils 4c of the parallel coil U2 are inserted into the third layer of slot 6 and the fourth layer of slot 13, as shown in Figure 4, forming the starting point of the winding in the third layer (2·i+1 layer). The pair of legs 40 of the other third-segment coil 4c of the parallel coil U2 are inserted into the fifth layer of slot 5 and the sixth layer of slot 12, as shown in Figure 4, forming the starting point of the winding in the fifth layer (2·i+1 layer). The parallel coil U3 of the stator coil 3u includes two third-segment coils 4c. A pair of legs 40 of one of the third-segment coils 4c of the parallel coil U3 are inserted into the third layer of slot 11 and the fourth layer of slot 18, as shown in Figure 4, forming the starting point of the winding in the third layer (2·i+1 layer). Furthermore, as shown in Figure 4, the pair of legs 40 of the other third-segment coil 4c of the parallel coil U3 are inserted into the fifth layer of slot 12 and the sixth layer of slot 19, forming the starting point of the winding in the fifth layer (2·i+1 layer). The parallel coil U4 of the stator coil 3u includes two third-segment coils 4c. As shown in Figure 4, the pair of legs 40 of one of the third-segment coils 4c of the parallel coil U4 are inserted into the third layer of slot 12 and the fourth layer of slot 19, forming the starting point of the winding in the third layer (2·i+1 layer). Furthermore, as shown in Figure 4, the pair of legs 40 of the other third-segment coil 4c of the parallel coil U4 are inserted into the fifth layer of slot 11 and the sixth layer of slot 18, forming the starting point of the winding in the fifth layer (2·i+1 layer).

[0025] The first to third segment coils 4a, 4b, and 4c that form the parallel coils V1-V4 of the stator coil 3v are assembled with a 4-slot offset in the circumferential direction (to the left in Figure 4) relative to the first to third segment coils 4a, 4b, and 4c that form the parallel coils U1-U4 of the U phase. Similarly, the first to third segment coils 4a, 4b, and 4c that form the parallel coils W1 and W2 of the stator coil 3w are assembled with a 4-slot offset in the circumferential direction relative to the first to third segment coils 4a, 4b, and 4c that form the parallel coils U1 and U2 of the U phase, on the opposite side (to the right in Figure 4) from the parallel coils V1 and V2. Furthermore, the first-to-third segment coils 4a, 4b, and 4c that form the parallel coils W3 and W4 of the stator coil 3w are assembled with a 4-slot offset in the circumferential direction from the parallel coils U1 and U2 (to the left in Figure 4) relative to the first-to-third segment coils 4a, 4b, and 4c that form the parallel coils V3 and V4 of the V phase.

[0026] As can be seen from Figure 4, the inclination direction of the connecting wire portions 41 (crank portions 42) of the first and second segment coils 4a and 4b with respect to the radial direction of the stator core 2 is the same, and the inclination direction of the connecting wire portion 41 (crank portions 42) of the third segment coil 4c with respect to the radial direction of the stator core 2 is also the same as that of the first and second segment coils 4a and 4b. Therefore, the first to third segment coils 4a, 4b, and 4c wound around the 2·i-1 and 2·i layers of the multiple slots 20, i.e., the first and second layers, the third and fourth layers, and the fifth and sixth layers, can be arranged in a ring shape as shown in Figure 5 using a well-known ring arrangement device (see, for example, Patent Document 2).

[0027] In assembly A, in which two layers of first-to-third segment coils 4a, 4b, and 4c are arranged in a ring shape, each second segment coil 4b is positioned to straddle the connecting wire portion 41 of the corresponding first segment coil 4a, and the multiple (six) third segment coils 4c are arranged circumferentially so that their connecting wire portions 41 overlap each other. As a result, as shown in Figure 6, it becomes possible to sequentially assemble the three assemblies A (first-to-third segment coils 4a, 4b, and 4c) that are wound around the first and second layers, the third and fourth layers, and the fifth and sixth layers onto the stator core 2. In this embodiment, as can be seen from Figures 4 and 6, the first and second segment coils 4a and 4b each include three types of segment coils with different spacings in the circumferential direction of a pair of legs 40, and the third segment coil 4c each includes two types of segment coils with different spacings in the circumferential direction of a pair of legs 40.

[0028] After the assembly of the first to third segment coils 4a, 4b, and 4c to the stator core 2 is complete, the legs 40 of the first to third segment coils 4a, 4b, and 4c that protrude from one end (twisted side) of the stator core 2 are twisted using a twisting device (not shown). In this embodiment, each pair of legs 40 of the first to third segment coils 4a, 4b, and 4c are twisted in opposite directions so that they are spaced apart from each other in the circumferential direction (see dashed lines in Figure 4). As can be seen in Figure 4, the tips of the two legs 40 of the first and second segment coils 4a and 4b that protrude from one 2·i layer and the other 2·i-1 layer on one side (winding start side) of the first and second slots 21 and 22, which are spaced five slots apart in the circumferential direction (for example, the second layer of slot 13 and the first layer of slot 18, etc.) are electrically joined together by welding (for example, laser welding, etc.).

[0029] As a result, multiple connecting wire portions 45 are formed on one end of the stator core 2, connecting the tips of the corresponding two legs 40 of the first and second segment coils 4a and 4b. As can be seen from Figure 4, the direction in which each connecting wire portion 45 crosses layers on one end of the stator core 2 (from layer 2·i to layer 2·i-1) is opposite to the direction in which the connecting wire portions 41 of the first to third segment coils 4a, 4b, and 4c cross layers on the other end of the stator core 2 (opposite the twisted side) (from layer 2·i-1 to layer 2·i). Prior to welding, the insulating coating is removed from the tips of each leg 40 so that the conductive material is exposed.

[0030] Furthermore, as shown in Figure 4, at one end of the stator core 2, two legs 40 protruding from one 2·i layer and the other 2·i+1 layer on one side (winding start side) of the circumferential direction of the first and second slots 21 and 22, which are spaced five slots apart (for example, the second layer of slot 48 and the third layer of slot 5, or the fourth layer of slot 1 and the fifth layer of slot 6), are twisted together and their tips are electrically joined by welding, so that the legs 40 of the first or second segment coils 4a and 4b that form the winding end portion in the 2·i layer are connected to the legs 40 of the third segment coil 4c that forms the winding start portion in the 2·i+1 layer. More specifically, at one end of the stator core 2, the legs 40 of the third segment coil 4c protruding from one of the 2·i+1 layers (for example, the third layer of slot 5 or the fifth layer of slot 6 in Figure 4) on one side (winding start side) of the predetermined first and second slots 21, 22 (for example, slots 5 and 12, and slots 6 and 13 in Figure 4, etc.) in the circumferential direction, and the legs 40 of the first or second segment coils 4a, 4b protruding from the 2·i layer (for example, the second layer of slot 48 or the fourth layer of slot 1 in Figure 4, etc.) of slot 20 located 5 slots away from one of the predetermined first and second slots 21, 22 (for example, slot 5 or slot 6 in Figure 4, etc.) are twisted together so that the ends of both are electrically joined.

[0031] As a result, multiple connecting wires 47 are formed on one end of the stator core 2, connecting the legs 40 of the first or second segment coils 4a, 4b that form the winding end portion in layer 2·i and the legs 40 of the third segment coil 4c that forms the winding start portion in layer 2·i+1 (see the area enclosed by the dashed line in Figure 7). As can be seen from Figure 4, on one end of the stator core 2, the direction in which each connecting wire 47 crosses layers (from layer 2·i to layer 2·i+1) is opposite to the direction in which the other connecting wires 45 (see the area enclosed by the double-dotted line in Figure 7) cross layers (from layer 2·i-1 to layer 2·i).

[0032] Once the corresponding leg portions 40 are joined together, the first to third segment coils 4a, 4b, and 4c are wound in a wave winding manner around the first and second layers, the third and fourth layers, and the fifth and sixth layers. The leg portions 40 inserted into the first layer of slots 5 and 6, and the sixth layer of slots 6 and 7, are used as lead wires Pu1, Pu2, Pu3, and Pu4 of parallel coils U1, U2, U3, and U4, as shown in Figure 4, and are electrically connected to the U-phase power lines at one end of the stator core 2 via a busbar unit (not shown). Furthermore, the legs 40 inserted into the 6th layer of slots 48 and 1, and the 1st layer of slots 11 and 12, are used as neutral wires Nu1, Nu2, Nu3, and Nu4 for parallel coils U1, U2, U3, and U4, as shown in Figure 4, and are electrically connected to the neutral point at one end of the stator core 2 via a busbar unit (not shown).

[0033] Furthermore, the legs 40 inserted into the first layer of slots 9 and 10, and the sixth layer of slots 10 and 11, are used as lead wires Pv1, Pv2, Pv3, and Pv4 of parallel coils V1, V2, V3, and V4, as shown in Figure 4, and are electrically connected to the V-phase power lines at one end of the stator core 2 via a busbar unit (not shown). In addition, the legs 40 inserted into the sixth layer of slots 4 and 5, and the first layer of slots 15 and 16, are used as neutral wires Nv1, Nv2, Nv3, and Nv4 of parallel coils V1, V2, V3, and V4, as shown in Figure 4, and are electrically connected to the neutral point at one end of the stator core 2 via a busbar unit (not shown). Furthermore, the legs 40 inserted into the first layer of slots 1 and 2, and the sixth layer of slots 14 and 15, are used as lead wires Pw1, Pw2, Pw3, and Pw4 of parallel coils W1, W2, W3, and W4, as shown in Figure 4, and are electrically connected to the W-phase power lines at one end of the stator core 2 via a busbar unit (not shown). In addition, the legs 40 inserted into the sixth layer of slots 44 and 45, and the first layer of slots 19 and 20, are used as neutral wires Nw1, Nw2, Nw3, and Nw4 of parallel coils W1, W2, W3, and W4, as shown in Figure 4, and are electrically connected to the neutral point at one end of the stator core 2 via a busbar unit (not shown). As a result, multiple stator coils 3u, 3v, and 3w are wound around the stator core 2 in a distributed winding manner.

[0034] In the multiple stator coils 3u, 3v, and 3w wound around the stator core 2, the joints between the tips of the numerous leg portions 40 are arranged radially in predetermined numbers to form an annular first coil end portion that protrudes outward from the end face of one end (twisted side) of the stator core 2. As described above, in the stator 1, since the corresponding leg portions 40 are joined at a 5-slot pitch on one end of the stator core 2, the first coil end portion can be made low-profile (the amount protruding from the end face of one end of the stator core 2 can be shortened).

[0035] Furthermore, in multiple stator coils 3u, 3v, 3w, the connecting wire portions 41 of the first to third segment coils 4a, 4b, 4c form an annular second coil end portion that protrudes outward from the other end (opposite side from the twisted side) of the stator core 2. In the second coil end portion, the connecting wire portion 41 of the second segment coil 4b straddles the connecting wire portion 41 of the first segment coil 4a. By limiting the overlap of the connecting wire portions 41 to two, the increase in axial length in the stator 1 can be effectively suppressed.

[0036] As described above, the stator 1 includes a plurality of first segment coils 4a, each having a pair of legs 40 inserted into two first slots 21 spaced six slots apart; a plurality of second segment coils 4b, each having a pair of legs 40 inserted into two second slots 22 spaced eight slots apart on either side of the first slots 21; and a plurality of third segment coils 4c, each having a pair of legs 40 inserted into predetermined first and second slots 21 and 22 spaced seven slots apart. The pair of legs 40 of the first segment coils 4a are inserted so as to protrude from one end of the stator core 2 into one 2·i-1 layer and the other 2·i layer on one side of the two first slots 21 in the circumferential direction. The pair of legs 40 of the second segment coil 4b are inserted so as to protrude from one end of the stator core 2 into one 2·i-1 layer and the other 2·i layer on one side of the two second slots 22 in the circumferential direction, and the second segment coil 4b straddles the corresponding first segment coil 4a. The pair of legs 40 of the third segment coil 4c are inserted so as to protrude from one end of the stator core 2 into one 2·i-1 layer and the other 2·i layer on one side of predetermined first and second slots 21, 22 in the circumferential direction, and the third segment coil 4c forms the winding start portion in the 2·i+1 layer. Also, at one end of the stator core 2, the two legs 40 protruding from one 2·i layer and the other 2·i-1 layer on one side of the first and second slots 21, 22, which are spaced 5 slots apart in the circumferential direction, are twisted together so that their ends are joined. Furthermore, at one end of the stator core 2, the two legs 40 protruding from one side of the 2·i layer and the other side of the 2·i+1 layer in the circumferential direction of the first and second slots 21 and 22, which are spaced five slots apart, are twisted so that the winding end in the 2·i layer and the winding start in the 2·i+1 layer are connected, and their tips are joined together.

[0037] In other words, each parallel coil U1-U4, V1-V4, W1-W4 is basically formed by inserting a second segment coil 4b into two second slots 22 spaced 8 slots apart, so as to straddle a first segment coil 4a inserted into two first slots 21 spaced 6 slots apart, and then joining the corresponding legs 40 at one end of the stator core 2 at a 5-slot pitch. As a result, even if the effective number of turns obtained by dividing the number of legs 40 in one slot 20 (number of layers = 6) by the number of parallel coils U-U4 (number of parallel = 4) is a non-integer (1.5 in this embodiment), the circulating current generated due to the timing difference in the generation of induced voltages at each magnetic pole of the parallel coils U1-U4, V1-V4, W1-W4 in response to the passage of the rotor's magnets can be canceled out within each parallel coil U1-U4, V1-V4, W1-W4, thereby suppressing the flow of circulating current to the stator coils 3u, 3v, 3w.

[0038] Taking the parallel coil U1 as an example, eight magnetic poles are formed in the parallel coil U1. As shown in Figure 4, in the magnetic poles (windings) formed in the range from slot 5 to slot 13, the legs 40 are evenly distributed on both sides in the circumferential direction with respect to the magnetic pole center (see the triangle in Figure 4) (two in slots 5 and 13, and one in slots 6 and 12). Similarly, in the magnetic poles formed in the range from slot 17 to slot 25, the legs 40 are evenly distributed on both sides in the circumferential direction with respect to the magnetic pole center (one in slots 17 and 25, and two in slots 18 and 24). Furthermore, in the magnetic poles formed in the range from slot 29 to slot 37, the legs 40 are evenly distributed on both sides in the circumferential direction with respect to the magnetic pole center (two in slots 29 and 37, and one in slots 30 and 36). Furthermore, in the magnetic poles formed in the range from slot 41 to slot 1, the legs 40 are evenly arranged on both sides in the circumferential direction with respect to the center of the magnetic pole (one each in slots 41 and 1, and two each in slots 42 and 48). Therefore, in these magnetic poles, there is no timing difference in the generation of induced voltage in response to the passage of a magnet.

[0039] On the other hand, in the magnetic poles formed in the range from slot 12 to slot 18, the legs 40 are biased to the other side in the circumferential direction relative to the magnetic pole center (the winding end side, the left side in Figure 4) (one each in slots 12 and 17, and two each in slots 13 and 18). Also, in the magnetic poles formed in the range from slot 36 to slot 42, the legs 40 are biased to the other side in the circumferential direction relative to the magnetic pole center (one each in slots 36 and 41, and two each in slots 37 and 42). As a result, in these magnetic poles, the timing of the generation of induced voltage in response to the passage of a magnet is shifted, for example, to the delayed side. In contrast, in the magnetic poles formed in the range from slot 24 to slot 30, the legs 40 are biased to one side in the circumferential direction relative to the magnetic pole center (the winding start side, the right side in Figure 4) (two each in slots 24 and 29, and one each in slots 25 and 30). Furthermore, in the magnetic poles formed in the range from slot 48 to slot 6, the legs 40 are arranged to be biased to one side in the circumferential direction relative to the magnetic pole center (two each in slots 48 and 5, and one each in slots 1 and 6). As a result, in these magnetic poles, the timing of the generation of induced voltage in response to the passage of a magnet is shifted, for example, to the leading side. Therefore, it can be understood that in parallel coil U1, the circulating current caused by the shift in the timing of induced voltage generation in the magnetic poles formed in the range from slot 12 to slot 18 and in the range from slot 36 to slot 42 can be canceled out with the circulating current caused by the shift in the timing of induced voltage generation in the magnetic poles formed in the range from slot 24 to slot 30 and in the range from slot 48 to slot 6. Then, in stator 1, similar to parallel coil U1, the circulating current due to the timing of induced voltage generation is canceled out within each parallel coil U2-U4, V1-V4, W1-W4.

[0040] In addition, in the stator 1, the legs 40 of the first to third segment coils 4a, 4b, and 4c, which form a single-phase stator coil 3u, 3v, or 3w, are inserted into every three adjacent slots 20 in the circumferential direction, and each of the multiple stator coils 3u, 3v, and 3w is wound around the stator core 2 by short-segment winding. For example, in the U-layer stator coil 3u, as shown in Figure 4, the legs 40 of the first to third segment coils 4a, 4b, and 4c are inserted at a 4-slot pitch, with 12 legs 40 each into slots 20 5, 6, and 7, slots 20 11, 12, and 13, slots 20 17, 18, and 19, slots 20 23, 24, and 25, slots 20 29, 30, and 31, slots 20 35, 36, and 37, slots 20 41, 42, and 43, and slots 20 47, 48, and 1. This makes it possible to increase the output (power) and reduce vibration and noise in a rotating electric machine including a stator 1 compared to a rotating electric machine including a stator in which the stator coil is wound around the stator core by full-slot winding. In addition, stator 1 eliminates the need for skew and other measures to reduce torque ripple of the order 6 × pole pair (e.g., 24th order).

[0041] Furthermore, in stator 1, the inclination direction of the jumper wire section 41 (crank section 42) connecting the pair of legs 40 of the third segment coil 4c with respect to the radial direction of the stator core 2 is the same as that of the first and second segment coils 4a and 4b. Therefore, it becomes possible to assemble the first to third segment coils 4a, 4b, and 4c, which are wound around the 2·i-1 layer and the 2·i layer, into the stator core 2 after arranging them in a ring shape using a well-known ring arrangement device. This makes it possible to shorten the cycle time and reduce costs by eliminating the use of multi-axis robots, etc. As a result, in stator 1, it is possible to suppress the generation of circulating current even if the effective number of turns is not an integer, and to improve productivity and reduce manufacturing costs.

[0042] Furthermore, in the stator 1, at one end of the stator core 2, the tip of the leg portion 40 of the third segment coil 4c that protrudes from one of the 2·i+1 layers on one side in the circumferential direction of predetermined first and second slots 21, 22, and the leg portion 40 that protrudes from the 2·i layer of slot 20 located 5 slots away from that side of the predetermined first and second slots 21, 22 are twisted together so that the tips of both are joined, thereby forming a jumper portion 47. In other words, in the stator 1, the leg portion 40 of the third segment coil 4c that forms the winding start portion in the 2·i+1 layer and the corresponding other leg portion 40 form a jumper portion 47 that spans the layer in the opposite direction to the other jumper portions 45. This makes it possible to arrange each second segment coil 4b in the stator core 2 so as to straddle the corresponding first segment coil 4a, and to join the corresponding leg portions 40 at a 5-slot pitch at one end of the stator core 2.

[0043] Furthermore, a portion of the leg portion 40 protruding from one end (the twisted end face) of the stator core 2 (see Figure 1) is used as lead wires Pu1, Pu2, Pu3, Pu4, Pv1, Pv2, Pv3, Pv4, Pw1, Pw2, Pw3, Pw4, and is connected to the U-phase, V-phase, or W-phase power lines to which power is applied. In addition, in the stator 1, the multiple stator coils 3u, 3v, 3w are connected by a Y connection, and a portion of the leg portion 40 protruding from one end (the twisted end face) of the stator core 2 (see Figure 1) is used as neutral wires Nu1, Nu2, Nu3, Nu4, Nv1, Nv2, Nv3, Nv4, Nw1, Nw2, Nw3, Nw4, which are connected to the neutral point. This allows the lead wires Pu1-Pw4 and neutral wires Nu1-Nw4 to be concentrated on one end of the stator core 2, simplifying the routing of power lines and the structure of the busbar unit. However, the multiple stator coils 3u, 3v, and 3w do not necessarily have to be connected by a Y connection; they may be connected by a delta connection or an open connection. Furthermore, the multiple stator coils 3u, 3v, and 3w may be composed of parallel coils U1-U4, V1-V4, and W1-W4 connected as shown in Figure 8.

[0044] Furthermore, as can be seen from Figures 1 and 4, in the stator 1, the legs 40 used as lead wires Pu1 and neutral wire Nu1 can be concentrated within a relatively narrow area of ​​the first coil end. This makes it possible to position the stator 1 inside a case or the like so that the legs 40 used as lead wires Pu1 and neutral wire Nu1 are not submerged in the coolant (cooling oil) when the rotating electric machine including the stator 1 is cooled by the coolant. As a result, the stator 1 can significantly reduce the cost required for insulating the exposed conductors of lead wires Pu1 and neutral wire Nu1. In addition, in the stator 1, the tips of the legs 40 inserted into the sixth layer on the innermost circumference are not joined together, eliminating the need to shift (protrude) the legs 40 inserted into the sixth layer toward the axis of the central hole 2o. Therefore, it becomes possible to assemble the rotor to the central hole 2o of the stator core 2 from both one end and the other end of the stator core 2.

[0045] Furthermore, in stator 1, the number of layers in each slot 20, 2·imax, may be an even number greater than 6, and the number of parallel coils in each stator coil 3u, 3v, 3w may be a multiple of 4 = 4·m (where "m" is an integer greater than or equal to 1). Also, the combination of the number of layers in each slot 20, 2·imax, and the number of parallel coils in each stator coil 3u, 3v, 3w, 4·m (2·imax, 4·m) is not limited to (6,4) in the above embodiment, but may be any of (10,4), (14,4), and (12,8), for example.

[0046] Figure 9 is an explanatory diagram illustrating another assembly configuration of the segment coil 4 to the stator core 2 of the stator 1 that satisfies the relationship n=6·p.

[0047] The stator coils 3u, 3v, and 3w, which are wound around the stator core 2 in the configuration shown in Figure 9, are formed by electrically joining a plurality of first, second, and third segment coils 4a', 4b', and 4c', respectively. Furthermore, the stator coil 3u includes four parallel coils U1, U2, U3, and U4 that are electrically connected in parallel. In addition, the stator coil 3v includes four parallel coils V1, V2, V3, and V4 that are electrically connected in parallel with each other, and the stator coil 3w includes four parallel coils W1, W2, W3, and W4 that are electrically connected in parallel with each other. The parallel coils U1-U4, V1-V4, and W1-W4 are connected to each other by a so-called 4Y connection.

[0048] The two legs 40 of the first-third segment coils 4a', 4b', and 4c' are inserted into different slots 20 from the other end of the stator core 2 so that they protrude from one end of the stator core 2 (the upper end in Figure 1), and the connecting wires 41 of the first-third segment coils 4a', 4b', and 4c' are aligned at the other end of the stator core 2. Furthermore, the first-third segment coils 4a', 4b', and 4c' are assembled to the stator core 2 such that an even number (in this case, six) of legs 40 protrude radially adjacent from each of the multiple slots 20. In addition, multiple layers (six layers in this embodiment) are formed by the multiple legs 40 protruding from each of the multiple slots 20 and adjacent in the circumferential direction of the stator core 2.

[0049] As shown in Figure 9, a pair of legs 40 of the first segment coil 4a' (see circles in Figure 9) are inserted from the other end of the stator core 2 (the front end of the paper in Figure 9) so as to protrude from one end of the stator core 2 (the back end of the paper in Figure 9). This is done by inserting the legs 40 of the first segment coil 4a' (see circles in Figure 9) into one 2·i-1 layer (where "i" is an integer greater than or equal to 1, i=1, ..., imax (in this embodiment, imax=3)) on one side (the winding start side) and the other 2·i layer on the other side of the stator core 2 on the circumferential direction of two first slots 21 that are spaced 4 slots apart. More specifically, the pair of legs 40 of the first segment coil 4a' that forms the parallel coil U1 of the stator coil 3u are inserted into the first layer of slot 5 and the second layer of slot 1, the first layer of slot 29 and the second layer of slot 25, the third layer of slot 41 and the fourth layer of slot 37, the third layer of slot 17 and the fourth layer of slot 13, and the fifth layer of slot 29 and the sixth layer of slot 25, as shown in Figure 9. Also, the pair of legs 40 of the first segment coil 4a' that forms the parallel coil U2 are inserted into the first layer of slot 41 and the second layer of slot 37, the first layer of slot 17 and the second layer of slot 13, the third layer of slot 29 and the fourth layer of slot 25, the fifth layer of slot 41 and the sixth layer of slot 37, and the fifth layer of slot 17 and the sixth layer of slot 13, as shown in Figure 9.

[0050] Furthermore, as shown in Figure 9, the pair of legs 40 of the first segment coil 4a' that forms the parallel coil U3 are inserted into the first layer of slot 47 and the second layer of slot 43, the first layer of slot 23 and the second layer of slot 19, the third layer of slot 35 and the fourth layer of slot 31, the third layer of slot 11 and the fourth layer of slot 7, and the fifth layer of slot 23 and the sixth layer of slot 19. Also, as shown in Figure 9, the pair of legs 40 of the first segment coil 4a' that forms the parallel coil U4 are inserted into the first layer of slot 35 and the second layer of slot 31, the first layer of slot 11 and the second layer of slot 7, the third layer of slot 23 and the fourth layer of slot 19, the fifth layer of slot 35 and the sixth layer of slot 31, and the fifth layer of slot 11 and the sixth layer of slot 7.

[0051] The pair of legs 40 of the second segment coil 4b' (see circles in Figure 9) are inserted from the other end of the stator core 2 so as to protrude from one end of the stator core 2 into one of the 2·i-1 layers and the other of the 2·i layers on one side (winding start side) of the circumferential direction of two second slots 22 spaced 6 slots apart on both sides of the first slot 21, and the connecting wire portion (not shown) of the second segment coil 4b' straddles the connecting wire portion (not shown) of the corresponding first segment coil 4a'. More specifically, the pair of legs 40 of the second segment coil 4b' that forms the parallel coil U1 of the stator coil 3u are inserted into the first layer of slot 42 and the second layer of slot 36, the first layer of slot 18 and the second layer of slot 12, the third layer of slot 30 and the fourth layer of slot 24, the fifth layer of slot 42 and the sixth layer of slot 36, and the fifth layer of slot 18 and the sixth layer of slot 12, as shown in Figure 9. Also, the pair of legs 40 of the second segment coil 4b' that forms the parallel coil U2 are inserted into the first layer of slot 6 and the second layer of slot 48, the first layer of slot 30 and the second layer of slot 24, the third layer of slot 42 and the fourth layer of slot 36, the third layer of slot 18 and the fourth layer of slot 12, and the fifth layer of slot 30 and the sixth layer of slot 24, as shown in Figure 9.

[0052] Furthermore, as shown in Figure 9, the pair of legs 40 of the second segment coil 4b' that forms the parallel coil U3 are inserted into the first layer of slot 36 and the second layer of slot 30, the first layer of slot 12 and the second layer of slot 6, the third layer of slot 24 and the fourth layer of slot 18, the fifth layer of slot 36 and the sixth layer of slot 30, and the fifth layer of slot 12 and the sixth layer of slot 6. Also, as shown in Figure 9, the pair of legs 40 of the second segment coil 4b' that forms the parallel coil U4 are inserted into the first layer of slot 48 and the second layer of slot 42, the first layer of slot 24 and the second layer of slot 18, the third layer of slot 36 and the fourth layer of slot 30, the third layer of slot 12 and the fourth layer of slot 6, and the fifth layer of slot 24 and the sixth layer of slot 18.

[0053] The pair of legs 40 of the third segment coil 4c' (see the circle in Figure 9) are inserted from the other end of the stator core 2 so as to protrude from one end of the stator core 2 into one 2·i+1 (=2·(i+1)-1) layer and the other 2·(i+1) layer on one side (winding start side) of predetermined first and second slots 21 and 22 spaced 5 slots apart in the circumferential direction, and one of the pair of legs 40 forms the winding start portion in the 2·i+1 layer. That is, the parallel coil U1 of the stator coil 3u includes two third segment coils 4c'. The pair of legs 40 of one of the third segment coils 4c' of the parallel coil U1 are inserted into the third layer of slot 5 and the fourth layer of slot 48, as shown in Figure 9, forming the winding start portion in the third layer (2·i+1 layer). As shown in Figure 9, the pair of legs 40 of the other third-segment coil 4c' of parallel coil U1 are inserted into the fifth layer of slot 6 and the sixth layer of slot 1, forming the starting point of the winding in the fifth layer (2·i+1 layer). The parallel coil U2 of the stator coil 3u includes two third-segment coils 4c'. As shown in Figure 9, the pair of legs 40 of one third-segment coil 4c' of parallel coil U2 are inserted into the third layer of slot 6 and the fourth layer of slot 1, forming the starting point of the winding in the third layer (2·i+1 layer). Also, as shown in Figure 9, the pair of legs 40 of the other third-segment coil 4c' of parallel coil U2 are inserted into the fifth layer of slot 5 and the sixth layer of slot 48, forming the starting point of the winding in the fifth layer (2·i+1 layer).

[0054] The parallel coil U3 of the stator coil 3u includes two third-segment coils 4c'. A pair of legs 40 of one of the third-segment coils 4c' of the parallel coil U3 are inserted into the third layer of slot 47 and the fourth layer of slot 42, as shown in Figure 9, forming the starting point of the winding in the third layer (2·i+1 layer). The pair of legs 40 of the other third-segment coil 4c' of the parallel coil U3 are inserted into the fifth layer of slot 48 and the sixth layer of slot 43, as shown in Figure 9, forming the starting point of the winding in the fifth layer (2·i+1 layer). The parallel coil U4 of the stator coil 3u includes two third-segment coils 4c'. A pair of legs 40 of one of the third-segment coils 4c' of the parallel coil U4 are inserted into the third layer of slot 48 and the fourth layer of slot 43, as shown in Figure 9, forming the starting point of the winding in the third layer (2·i+1 layer). Furthermore, the pair of legs 40 of the other third segment coil 4c' of the parallel coil U4 are inserted into the fifth layer of slot 47 and the sixth layer of slot 42, as shown in Figure 9, forming the starting point of the winding in the fifth layer (2·i+1 layer).

[0055] The first to third segment coils 4a', 4b', and 4c' that form the parallel coils V1-V4 of the stator coil 3v are assembled with a 4-slot offset in the circumferential direction (to the left in Figure 9) relative to the first to third segment coils 4a', 4b', and 4c' that form the parallel coils U1-U4 of the U phase. Similarly, the first to third segment coils 4a', 4b', and 4c' that form the parallel coils W1 and W2 of the stator coil 3w are assembled with a 4-slot offset in the circumferential direction relative to the first to third segment coils 4a', 4b', and 4c' that form the parallel coils U1 and U2 of the U phase (to the right in Figure 9). Furthermore, the first-to-third segment coils 4a', 4b', and 4c' that form the parallel coils W3 and W4 of the stator coil 3w are assembled with a 4-slot offset in the circumferential direction from the parallel coils U1 and U2 (to the left in Figure 9) relative to the first-to-third segment coils 4a', 4b', and 4c' that form the parallel coils V3 and V4 of the V phase.

[0056] As can be seen from Figure 9, the inclination direction of the connecting wire portions 41 (crank portions 42) of the first and second segment coils 4a' and 4b' with respect to the radial direction of the stator core 2 is the same, and the inclination direction of the connecting wire portion 41 (crank portions 42) of the third segment coil 4c' with respect to the radial direction of the stator core 2 is also the same as that of the first and second segment coils 4a' and 4b'. Therefore, the first to third segment coils 4a', 4b', and 4c' wound around the 2·i-1 and 2·i layers of the multiple slots 20, i.e., the first and second layers, the third and fourth layers, and the fifth and sixth layers, can be arranged in a ring shape using a well-known ring arrangement device (see, for example, Patent Document 2) (see Figure 5). As a result, it becomes possible to sequentially assemble the three assemblies (first-third segment coils 4a', 4b', 4c') that are wound around the first and second layers, the third and fourth layers, and the fifth and sixth layers onto the stator core 2. The first and second segment coils 4a' and 4b' each include three types of segment coils with different spacings in the circumferential direction of a pair of legs 40, and the third segment coil 4c' each includes two types of segment coils with different spacings in the circumferential direction of a pair of legs 40.

[0057] After the assembly of the first to third segment coils 4a', 4b', and 4c' to the stator core 2 is complete, the pair of legs 40 of each first to third segment coil 4a', 4b', and 4c' are twisted to opposite sides so that they are spaced apart from each other in the circumferential direction (see dashed lines in Figure 9). As can be seen in Figure 9, the tips of the two legs 40 of the first and second segment coils 4a' and 4b' that protrude from one side (winding start side) of the first and second slots 21 and 22, which are spaced seven slots apart in the circumferential direction (for example, the second layer of slot 1 and the first layer of slot 42, etc.) are electrically joined together by welding (for example, laser welding, etc.). As a result, multiple jumper wires 45 connecting the tips of the corresponding two legs 40 of the first and second segment coils 4a' and 4b' are formed on one end side of the stator core 2. As can be seen from Figure 9, the direction in which each connecting wire portion 45 crosses layers at one end of the stator core 2 (from layer 2·i to layer 2·i-1) is opposite to the direction in which the connecting wire portions 41 of the first to third segment coils 4a′, 4b′, 4c′ cross layers at the other end of the stator core 2 (from layer 2·i-1 to layer 2·i).

[0058] Furthermore, as shown in Figure 9, at one end of the stator core 2, two legs 40 protruding from one 2·i layer and the other 2·i+1 layer on one side (winding start side) of the circumferential direction of the first and second slots 21 and 22, which are spaced 7 slots apart (for example, the second layer of slot 12 and the third layer of slot 5, or the fourth layer of slot 13 and the fifth layer of slot 6), are twisted together and their tips are electrically joined by welding, so that the legs 40 of the first or second segment coils 4a', 4b' that form the winding end portion in the 2·i layer and the legs 40 of the third segment coil 4c' that form the winding start portion in the 2·i+1 layer are connected. More specifically, at one end of the stator core 2, the legs 40 of the third segment coil 4c' protruding from one of the 2·i+1 layers (for example, the third layer of slot 5 or the fifth layer of slot 6 in Figure 9) on one side (winding start side) of the predetermined first and second slots 21, 22 (for example, slots 5 and 48, and slots 6 and 1 in Figure 9) in the circumferential direction, and the legs 40 of the first or second segment coils 4a', 4b' protruding from the 2·i layer (for example, the second layer of slot 12 or the fourth layer of slot 13 in Figure 9) of slot 20 located 7 slots away from one of the predetermined first and second slots 21, 22 (for example, slot 5 or slot 6 in Figure 9), are twisted together so that the ends of both are electrically joined.

[0059] As a result, multiple connecting wires 47 are formed on one end of the stator core 2, connecting the legs 40 of the first or second segment coils 4a', 4b' that form the winding end portion in layer 2·i and the legs 40 of the third segment coil 4c' that forms the winding start portion in layer 2·i+1 (see the area enclosed by the dashed line in Figure 7). As can be seen from Figure 9, on one end of the stator core 2, the direction in which each connecting wire 47 crosses layers (from layer 2·i to layer 2·i+1) is opposite to the direction in which the other connecting wires 45 (see the area enclosed by the double-dotted line in Figure 7) cross layers (from layer 2·i-1 to layer 2·i).

[0060] Once the corresponding ends of the legs 40 are joined together, the first to third segment coils 4a', 4b', and 4c' are wound in a wave winding manner around the first and second layers, the third and fourth layers, and the fifth and sixth layers. The legs 40 inserted into the first layer of slots 5 and 6, and the sixth layer of slots 6 and 7, are used as lead wires Pu1, Pu2, Pu3, and Pu4 of parallel coils U1, U2, U3, and U4, as shown in Figure 9, and are electrically connected to the U-phase power lines at one end of the stator core 2 via a busbar unit (not shown). Furthermore, the legs 40 inserted into the sixth layer of slots 12 and 13, and the first layer of slots 47 and 48, are used as neutral wires Nu1, Nu2, Nu3, and Nu4 for parallel coils U1, U2, U3, and U4, respectively, as shown in Figure 9, and are electrically connected to the neutral point at one end of the stator core 2 via a busbar unit (not shown).

[0061] Furthermore, the legs 40 inserted into the first layer of slots 9 and 10, and the sixth layer of slots 10 and 11, are used as lead wires Pv1, Pv2, Pv3, and Pv4 of parallel coils V1, V2, V3, and V4, as shown in Figure 9, and are electrically connected to the V-phase power lines at one end of the stator core 2 via a busbar unit (not shown). In addition, the legs 40 inserted into the sixth layer of slots 16 and 17, and the first layer of slots 3 and 4, are used as neutral wires Nv1, Nv2, Nv3, and Nv4 of parallel coils V1, V2, V3, and V4, as shown in Figure 9, and are electrically connected to the neutral point at one end of the stator core 2 via a busbar unit (not shown). Furthermore, the legs 40 inserted into the first layer of slots 1 and 2, and the sixth layer of slots 14 and 15, are used as lead wires Pw1, Pw2, Pw3, and Pw4 of parallel coils W1, W2, W3, and W4, as shown in Figure 9, and are electrically connected to the W-phase power lines at one end of the stator core 2 via a busbar unit (not shown). In addition, the legs 40 inserted into the sixth layer of slots 8 and 9, and the first layer of slots 7 and 8, are used as neutral wires Nw1, Nw2, Nw3, and Nw4 of parallel coils W1, W2, W3, and W4, as shown in Figure 9, and are electrically connected to the neutral point at one end of the stator core 2 via a busbar unit (not shown). As a result, multiple stator coils 3u, 3v, and 3w are wound around the stator core 2 in a distributed winding manner.

[0062] In the stator coils 3u, 3v, and 3w wound around the stator core 2 in the manner shown in Figure 9, the joints between the tips of the numerous leg portions 40 are arranged radially in predetermined numbers to form annular first coil end portions that protrude outward from the end face of one end (torsion side) of the stator core 2. Furthermore, in the stator coils 3u, 3v, and 3w wound around the stator core 2 in the manner shown in Figure 9, the connecting wire portions 41 of the first to third segment coils 4a', 4b', and 4c' form annular second coil end portions that protrude outward from the end face of the other end (opposite side from the torsion side) of the stator core 2. In the second coil end portions, the connecting wire portion 41 of the second segment coil 4b' straddles the connecting wire portion 41 of the first segment coil 4a', but by limiting the overlap of the connecting wire portions 41 to a double, the increase in the axial length of the stator 1 to which the manner shown in Figure 9 is applied can be effectively suppressed.

[0063] As described above, the stator 1 to which the embodiment shown in Figure 9 is applied includes a first segment coil 4a' having a pair of legs 40 inserted into two first slots 21 spaced four slots apart, a second segment coil 4b' having a pair of legs 40 inserted into two second slots 22 spaced six slots apart on both sides of the first slots 21, and a third segment coil 4c' having a pair of legs 40 inserted into predetermined first and second slots 21, 22 spaced five slots apart. The pair of legs 40 of the first segment coil 4a' are inserted so as to protrude from one end of the stator core 2 into one 2·i-1 layer and the other 2·i layer on one side in the circumferential direction of the two first slots 21. The pair of legs 40 of the second segment coil 4b' are inserted so as to protrude from one end of the stator core 2 into one 2·i-1 layer and the other 2·i layer on one side of the two second slots 22 in the circumferential direction, and the second segment coil 4b' straddles the corresponding first segment coil 4a'. The pair of legs 40 of the third segment coil 4c' are inserted so as to protrude from one end of the stator core 2 into one 2·i-1 layer and the other 2·i layer on one side of predetermined first and second slots 21, 22 in the circumferential direction, forming the winding start portion in the 2·i+1 layer. Also, at one end of the stator core 2, the two legs 40 protruding from one 2·i layer and the other 2·i-1 layer on one side of the first and second slots 21, 22, which are spaced 7 slots apart, are twisted together so that their ends are joined. Furthermore, at one end of the stator core 2, two legs 40 protruding from one side of the 2·i layer and the other side of the 2·i+1 layer in the circumferential direction of the first and second slots 21 and 22, which are spaced 7 slots apart, are twisted so that the winding end in the 2·i layer and the winding start in the 2·i+1 layer are connected, and their tips are joined together.

[0064] In other words, each parallel coil U1-U4, V1-V4, W1-W4 shown in Figure 9 is basically formed by inserting a second segment coil 4b' into two second slots 22 spaced six slots apart, so as to straddle a first segment coil 4a' inserted into two first slots 21 spaced four slots apart, and then joining the corresponding legs 40 at one end of the stator core 2 at a seven-slot pitch. As a result, even if the effective number of turns obtained by dividing the number of legs 40 in one slot 20 (number of layers = 6) by the number of parallel coils U-U4 (number of parallel = 4) is a non-integer (1.5 in this embodiment), the circulating current generated by the timing difference in the generation of induced voltages at each magnetic pole of the parallel coils U1-U4, V1-V4, W1-W4 in response to the passage of the rotor's magnets can be canceled out within each parallel coil U1-U4, V1-V4, W1-W4, thereby suppressing the flow of circulating current to the stator coils 3u, 3v, 3w.

[0065] Taking the parallel coil U1 as an example, eight magnetic poles are formed in the parallel coil U1. As shown in Figure 9, in the magnetic poles (windings) formed in the range from slot 6 to slot 48, the legs 40 are evenly distributed on both sides in the circumferential direction with respect to the magnetic pole center (see the triangle in Figure 9) (one each in slots 6 and 48, and two each in slots 5 and 1). Similarly, in the magnetic poles formed in the range from slot 42 to slot 36, the legs 40 are evenly distributed on both sides in the circumferential direction with respect to the magnetic pole center (two each in slots 42 and 36, and one each in slots 41 and 37). Furthermore, in the magnetic poles formed in the range from slot 30 to slot 24, the legs 40 are evenly distributed on both sides in the circumferential direction with respect to the magnetic pole center (one each in slots 30 and 24, and two each in slots 29 and 25). Furthermore, in the magnetic poles formed in the range from slot 18 to slot 12, the legs 40 are evenly arranged on both sides in the circumferential direction with respect to the center of the magnetic pole (two in slots 18 and 12, and one in slots 17 and 13). Therefore, in these magnetic poles, there is no timing difference in the generation of induced voltage in response to the passage of a magnet.

[0066] On the other hand, in the magnetic poles formed in the range from slot 1 to slot 41, the legs 40 are biased to one side in the circumferential direction relative to the magnetic pole center (the winding start side, the left side in Figure 9) (two in slots 1 and 42, and one in slots 48 and 41). Also, in the magnetic poles formed in the range from slot 25 to slot 17, the legs 40 are biased to one side in the circumferential direction relative to the magnetic pole center (two in slots 25 and 18, and one in slots 24 and 17). As a result, in these magnetic poles, the timing of the generation of induced voltage in response to the passage of a magnet is shifted, for example, to the delayed side. In contrast, in the magnetic poles formed in the range from slot 37 to slot 29, the legs 40 are biased to the other side in the circumferential direction relative to the magnetic pole center (the winding end side, the right side in Figure 9) (one in slots 37 and 30, and two in slots 36 and 29). Furthermore, in the magnetic poles formed in the range from slot 13 to slot 5, the legs 40 are arranged to be biased to the other side in the circumferential direction relative to the magnetic pole center (one each in slots 13 and 6, and two each in slots 12 and 5). As a result, in these magnetic poles, the timing of the generation of induced voltage in response to the passage of a magnet is shifted, for example, to the leading side. Therefore, it can be understood that in parallel coil U1, the circulating current caused by the shift in the timing of induced voltage generation in the magnetic poles formed in the range from slot 1 to slot 41 and in the range from slot 25 to slot 17 can be canceled out with the circulating current caused by the shift in the timing of induced voltage generation in the magnetic poles formed in the range from slot 37 to slot 29 and in the range from slot 13 to slot 5. In the embodiment shown in Figure 9, similar to parallel coil U1, the circulating current due to the timing of induced voltage generation is canceled out within each parallel coil U2-U4, V1-V4, W1-W4.

[0067] Furthermore, in the stator 1 to which the embodiment shown in Figure 9 is applied, the legs 40 of the first to third segment coils 4a', 4b', 4c' that form a single-phase stator coil 3u, 3v, or 3w are inserted into every three adjacent slots 20 in the circumferential direction, and each of the multiple stator coils 3u, 3v, 3w is wound around the stator core 2 by short-segment winding. For example, in the U-layer stator coil 3u, as shown in Figure 9, the legs 40 of the first to third segment coils 4a', 4b', and 4c' are inserted at a 4-slot pitch, with 12 legs 40 each into slots 20 7, 6, and 5; slots 20 1, 48, and 47; slots 20 43, 42, and 41; slots 20 37, 36, and 35; slots 20 31, 30, and 29; slots 20 25, 24, and 23; slots 20 19, 18, and 17; and slots 20 13, 12, and 11. As a result, a rotating electric machine including a stator 1 to which the embodiment shown in Figure 9 is applied can have higher output (power) and reduced vibration and noise compared to a rotating electric machine including a stator in which the stator coil is wound around the stator core by full-slot winding. In addition, according to the embodiment shown in Figure 9, skew and other measures to reduce torque ripple of the 6th order × pole pair order (for example, 24th order) can be omitted.

[0068] Furthermore, in the stator 1 to which the embodiment shown in Figure 9 is applied, the inclination direction of the jumper wire portion 41 (crank portion 42) connecting the pair of legs 40 of the third segment coil 4c' with respect to the radial direction of the stator core 2 is the same as that of the first and second segment coils 4a', 4b'. Therefore, it becomes possible to assemble the first to third segment coils 4a', 4b', 4c' wound around the 2·i-1 layer and 2·i layer into the stator core 2 after arranging them in a ring shape using a well-known ring arrangement device. This makes it possible to shorten the cycle time and reduce costs by eliminating the use of multi-axis robots, etc. As a result, the stator 1 can suppress the generation of circulating current even if the effective number of turns is not an integer, and it is possible to improve productivity and reduce manufacturing costs.

[0069] Furthermore, in the stator 1 to which the embodiment shown in Figure 9 is applied, at one end of the stator core 2, the tip of the leg portion 40 of the third segment coil 4c' that protrudes from one of the 2·i+1 layers on one side in the circumferential direction of predetermined first and second slots 21, 22 and the leg portion 40 that protrudes from the 2·i layer of slot 20 located 7 slots away from that side of the predetermined first and second slots 21, 22 are twisted together so that the tips of both are joined, thereby forming a jumper portion 47. In other words, in the stator 1, the leg portion 40 of the third segment coil 4c' that forms the winding start portion in the 2·i+1 layer and the corresponding other leg portion 40 form a jumper portion 47 that spans the layer in the opposite direction to the other jumper portions 45. This allows each second segment coil 4b' to be positioned on the stator core 2 so as to straddle the corresponding first segment coil 4a', and also makes it possible to join the corresponding leg portions 40 at one end of the stator core 2 at a 7-slot pitch.

[0070] Furthermore, a portion of the leg portion 40 protruding from one end (the twisted end face) of the stator core 2 is used as lead wires Pu1, Pu2, Pu3, Pu4, Pv1, Pv2, Pv3, Pv4, Pw1, Pw2, Pw3, Pw4, and is connected to the U-phase, V-phase, or W-phase power lines to which power is applied. In addition, in the stator 1 to which the embodiment shown in Figure 9 is applied, the multiple stator coils 3u, 3v, 3w are connected by a Y connection, and a portion of the leg portion 40 protruding from one end (the twisted end face) of the stator core 2 is used as neutral wires Nu1, Nu2, Nu3, Nu4, Nv1, Nv2, Nv3, Nv4, Nw1, Nw2, Nw3, Nw4 connected to the neutral point. This allows the lead wires Pu1-Pw4 and neutral wires Nu1-Nw4 to be concentrated on one end of the stator core 2, simplifying the routing of power lines and the structure of the busbar unit. However, in the stator 1 to which the embodiment shown in Figure 9 is applied, the multiple stator coils 3u, 3v, and 3w do not necessarily have to be connected by a Y connection, but may be connected by a delta connection or an open connection, and may be composed of parallel coils U1-U4, V1-V4, and W1-W4 connected as shown in Figure 8.

[0071] Furthermore, in the embodiment shown in Figure 9, the leg portions 40 used as lead wires Pu1, neutral wire Nu1, etc., can be concentrated within a relatively narrow area of ​​the first coil end. This makes it possible to position the stator 1 inside the case, etc., so that the leg portions 40 used as lead wires Pu1, etc., and neutral wire Nu1, etc., are not submerged (immersed) in the coolant (cooling oil) when the rotating electric machine including the stator 1 is cooled by the coolant. As a result, the cost required for insulating the exposed conductor portions of lead wires Pu1, etc., and neutral wire Nu1, etc., can be significantly reduced. In addition, in the embodiment shown in Figure 9, the tips of the leg portions 40 inserted into the sixth layer on the innermost circumference side are not joined together, eliminating the need to shift (protrude) the leg portions 40 inserted into the sixth layer toward the axis of the central hole 2o. Therefore, it becomes possible to assemble the rotor to the central hole 2o of the stator core 2 from both one end and the other end of the stator core 2. Furthermore, in the embodiment shown in Figure 9, the second segment coil 4b' is inserted into two second slots 22 spaced six slots apart, so as to straddle the first segment coil 4a' which is inserted into two first slots 21 spaced four slots apart. This makes it possible to further reduce the height of the second coil end portion (shorten the amount of protrusion from the other end face of the stator core 2).

[0072] Furthermore, in the stator 1 to which the embodiment shown in Figure 9 is applied, the number of layers in each slot 20, 2·imax, may be an even number greater than 6, and the number of parallel coils in each stator coil 3u, 3v, 3w may be a multiple of 4 = 4·m (where "m" is an integer greater than or equal to 1). Also, the combination of the number of layers in each slot 20, 2·imax, and the number of parallel coils in each stator coil 3u, 3v, 3w, 4·m (2·imax, 4·m) is not limited to (6,4) in the above embodiment, but may be any of (10,4), (14,4), and (12,8), for example.

[0073] Furthermore, the invention disclosed herein is not limited in any way to the embodiments described above, and it goes without saying that various modifications can be made within the scope of this disclosure. Moreover, the embodiments described above are merely one specific form of the invention described in the summary of the invention, and do not limit the elements of the invention described in the summary of the invention. [Industrial applicability]

[0074] The invention disclosed herein can be used in industries such as stator manufacturing. [Explanation of Symbols]

[0075] 1 Stator, 2 Stator core, 2o Center hole, 2t Teeth section, 20 Slot, 21 First slot, 22 Second slot, 3u, 3v, 3w Stator coil, 4 Segment coil, 4a, 4a' First segment coil, 4b, 4b' Second segment coil, 4c, 4c' Third segment coil, 40 Leg section, 41, 45, 47 Jumper wire section, 42 Crank section, A Assembly, Nu1, Nu2, Nu3, Nu4, Nv1, Nv2, Nv3, Nv4, Nw1, Nw2, Nw3, Nw4 Neutral wire, Pu1, Pu2, Pu3, Pu4, Pv1, Pv2, Pv3, Pv4, Pw1, Pw2, Pw3, Pw4 Lead wires, U1, U2, U3, U4, V1, V2, V3, V4, W1, W2, W3, W4 parallel coils.

Claims

1. A stator comprising a stator core including a plurality of slots formed circumferentially spaced apart so as to extend radially, and a plurality of segment coils having pairs of legs inserted into different slots and forming a plurality of stator coils by electrical joining of the tips of the corresponding legs, Let the number of poles be "p" and the number of slots be "n", then n = 6 * p, Each of the aforementioned multiple stator coils includes 4·m parallel coils (where "m" is an integer of 1 or more) connected in parallel. An even number of the legs are inserted into one of the slots, arranged in the radial direction. The plurality of segment coils are, A first segment coil is inserted into one of the 2.i-1 layers (where "i" is an integer greater than or equal to 1, i = 1, ..., imax) and the other 2.i layer of two first slots spaced six slots apart, such that the pair of legs protrude from one end of the stator core. The pair of legs are inserted into the 2.i-1 layer on one side and the 2.i layer on the other side of the circumferential direction of the two second slots, which are spaced eight slots apart on both sides of the first slot, so as to protrude from one end of the stator core, and the second segment coil spans the corresponding first segment coil, The stator core includes a third segment coil in which the pair of legs are inserted into one 2.i-1 layer and the other 2.i layer on one side of predetermined first and second slots spaced seven slots apart in the circumferential direction, with the legs protruding from one end of the stator core, and forming a winding start portion in the 2.i+1 layer, A stator in which, at one end of the stator core, two legs protruding from one 2.i layer and the other 2.i-1 layer on one side in the circumferential direction of the first and second slots spaced five slots apart are twisted so that their tips are joined together, and the winding end of the 2.i layer and the winding start of the 2.i+1 layer are connected, by which two legs protruding from one 2.i layer and the other 2.i+1 layer on one side in the circumferential direction of the first and second slots spaced five slots apart are twisted so that their tips are joined together.

2. In the stator according to claim 1, A stator in which, at one end of the stator core, the tip of the leg of the third segment coil protruding from one of the 2.i+1 layers on one side in the circumferential direction of the predetermined first and second slots and the leg protruding from the 2.i layer of the slot located 5 slots away from one side of the predetermined first and second slots are twisted and joined together.

3. In the stator according to claim 1 or 2, A portion of the leg portion protruding from one end of the stator core is connected to a power line to which power is applied.

4. In the stator according to claim 3, The plurality of stator coils are connected by a Y-connection, and a portion of the leg portion protruding from one end of the stator core is connected to the neutral point of the stator.

5. In the stator according to claim 1 or 2, A stator in which the combination of the number of layers in the slot (2 imax) and the number of parallel coils (4 m) is one of the following: (6, 4), (10, 4), (14, 4), and (12, 8).

6. A stator comprising a stator core including a plurality of slots formed circumferentially spaced apart so as to extend radially, and a plurality of segment coils having pairs of legs inserted into different slots and forming a plurality of stator coils by electrical joining of the tips of the corresponding legs, Let the number of poles be "p" and the number of slots be "n", then n = 6 * p, Each of the aforementioned multiple stator coils includes 4·m parallel coils (where "m" is an integer of 1 or more) connected in parallel. An even number of the legs are inserted into one of the slots, arranged in the radial direction. The plurality of segment coils are, A first segment coil is inserted into one of the 2.i-1 layers (where "i" is an integer greater than or equal to 1, i = 1, ..., imax) and the other 2.i layer of two first slots spaced four slots apart, such that the pair of legs protrude from one end of the stator core. The pair of legs are inserted into the 2.i-1 layer on one side and the 2.i layer on the other side of the circumferential direction of the two second slots, which are spaced six slots apart on both sides of the first slot, so as to protrude from one end of the stator core, and the second segment coil spans the corresponding first segment coil, The stator core includes a third segment coil in which the pair of legs are inserted into one 2.i-1 layer and the other 2.i layer on one side of predetermined first and second slots spaced five slots apart in the circumferential direction, with the legs protruding from one end of the stator core, and forming a winding start portion in the 2.i+1 layer, A stator in which, at one end of the stator core, two legs protruding from one 2.i layer and the other 2.i-1 layer on one side in the circumferential direction of the first and second slots spaced seven slots apart are twisted so that their tips are joined together, and the winding end of the 2.i layer and the winding start of the 2.i+1 layer are connected, by which two legs protruding from one 2.i layer and the other 2.i+1 layer on one side in the circumferential direction of the first and second slots spaced seven slots apart are twisted so that their tips are joined together.

7. In the stator according to claim 6, A stator in which, at one end of the stator core, the tip of the leg of the third segment coil protruding from one of the 2.i+1 layers on one side in the circumferential direction of the predetermined first and second slots and the leg protruding from the 2.i layer of the slot located 7 slots away from one side of the predetermined first and second slots are twisted and joined together.

8. In the stator according to claim 6 or 7, A portion of the leg portion protruding from one end of the stator core is connected to a power line to which power is applied.

9. In the stator according to claim 8, The plurality of stator coils are connected by a Y-connection, and a portion of the leg portion protruding from one end of the stator core is connected to the neutral point of the stator.

10. In the stator according to claim 6 or 7, A stator in which the combination of the number of layers in the slot (2 imax) and the number of parallel coils (4 m) is one of the following: (6, 4), (10, 4), (14, 4), and (12, 8).

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