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 6 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 6 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 sections (legs) of a plurality of U-shaped conductor segments (segment coils) into corresponding slots so that they protrude from one end (twisted side) in the axial direction of the stator core, and twisting each straight section in the circumferential direction to join the tips of two corresponding straight sections. In other words, the multiple conductor segments include a first conductor segment in which a pair of linear sections are inserted into two first slots spaced five slots apart, a second conductor segment in which a pair of linear sections are inserted into two second slots spaced seven slots apart on either side of the first slot, and a third conductor segment in which a pair of linear sections 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, the 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). Then, at one end of the stator core, the 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 an electric motor including a stator as described in Patent Document 1, the output characteristics change according to 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 electric motor 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 a pair of legs inserted into different slots and forming a plurality of stator coils by electrical joining of the tips of the corresponding legs, wherein when the number of poles is "p" and the number of slots is "n", n = 6·p, and the plurality of stator coils are each connected in parallel in a number of 4·m (where "m" is an integer of 1 or more). The segment coils include a parallel coil, in which an even number of the legs are inserted radially into one slot, and the plurality of segment coils include a first segment coil in which the pair of legs are inserted so as to protrude from one end of the stator core into one 2·i-1 layer on one side of two first slots spaced 5 slots apart in the circumferential direction (where "i" is an integer greater than or equal to 1, i=1,...,imax) and the other 2·i layer, and a second segment coil in which the pair of legs are inserted so as to protrude from one end of the stator core into two second slots spaced 7 slots apart on both sides of the first slot The stator core includes a second segment coil that spans the corresponding first segment coil, with the pair of legs inserted into the 2·i-1 layer and the other 2·i layer so as to protrude from one end of the stator core, and a third segment coil that forms the end of the winding in the 2·i layer or the beginning of the winding in the 2·i+1 layer, with the pair of legs inserted into the 2·i-1 layer and the other 2·i layer on one side of the circumferential direction of predetermined first and second slots spaced 6 slots apart, with the pair of legs protruding from the one end of the stator core, and the stator core includes a second segment coil that spans the corresponding first segment coil, and the stator core includes a second segment coil that spans the corresponding first segment coil, with the pair of legs inserted into the 2·i-1 layer and the other 2·i layer on one side so as to protrude from the one end of the stator core, and the end of the winding in the 2·i layer or the beginning of the winding in the 2·i+1 layer, At one end of the core, the 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 six 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, so that the 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 six slots apart are twisted so that their tips are joined together.

[0008] The stator of the present disclosure includes a first segment coil, the legs of which are inserted into two first slots spaced five slots apart; a second segment coil, the legs of which are inserted into two second slots spaced seven slots apart on either side of the first slot; and a third segment coil, the legs of which are inserted into predetermined first and second slots spaced six slots apart. The 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 and the other 2·i layer on one side of the two first slots in the circumferential direction. The 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 the two second slots in the circumferential direction, and the second segment coil straddles the corresponding first segment coil. A pair of legs of the third segment coil are inserted into one 2·i-1 layer and the other 2·i layer on one side of predetermined first and second slots in the circumferential direction, with the legs protruding from one end of the stator core, forming the winding end portion in the 2·i layer or the winding start portion in the 2·i+1 layer. At one end of the stator core, the two legs protruding from one 2·i layer and the other 2·i-1 layer on one side of the first and second slots, which are spaced 6 slots apart in the circumferential direction, are twisted so that their tips are joined together. Furthermore, at one end of the stator core, the two legs protruding from one 2·i layer and the other 2·i+1 layer on one side of the first and second slots, which are spaced 6 slots apart in the circumferential direction, are twisted so that the winding end portion in the 2·i layer and the winding start portion in the 2·i+1 layer are connected, with their tips being joined together.

[0009] In other words, each parallel coil is formed by inserting a second segment coil into two second slots spaced seven slots apart, so as to straddle a first segment coil inserted into two first slots spaced five slots apart, and then joining the corresponding legs at one end of the stator core at a six-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 inclination direction with respect to the radial direction of the stator core of the portion connecting the pair of legs of the third segment coil (jumper wire portion) is the same as that of the first and second segment coils, so that the first to third segment coils wound around the 2·i-1 layer and 2·i layer can be assembled to the stator core after being arranged 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 of this disclosure suppresses the generation of circulating current even when the effective number of turns is not an integer, and improves productivity and reduces manufacturing costs. [Brief explanation of the drawing]

[0010] [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 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 6] 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 7] This is a perspective view showing an assembly of segment coils. [Figure 8] This is a perspective view showing the assembly procedure for the segment coil assembly to the stator core. [Figure 9] This is an enlarged perspective view showing the essential parts of the stator of this disclosure. [Figure 10] This is a schematic diagram showing other stator coils applicable to the stator of this disclosure. [Modes for carrying out the invention]

[0011] Next, with reference to the drawings, embodiments for carrying out the invention of this disclosure will be described.

[0012] 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).

[0013] 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.

[0014] 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.

[0015] 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 bridging portion 41 that connects the pair of leg portions 40 to each other. Further, a crank portion 42 is formed on the bridging 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 bridging portions 41 of the first to third segment coils 4a, 4b, 4c are aligned on the other end side of the stator core 2.

[0016] 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 that protrude from each of the plurality of slots 20 and are circumferentially adjacent to each other on the stator core 2. Hereinafter, the layer of the plurality of leg portions 40 (tip portions) that are circumferentially adjacent to each other 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 that are circumferentially adjacent to each other 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.

[0017] Next, while referring to FIG. 4, taking the stator coil 3u as an example, the assembling manner 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 of the first segment coil 4a are inserted from the other 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 2·i - 1 layer (where "i" is an integer of 1 or more, i = 1,..., imax (in this embodiment, imax = 3)) and the other 2·i layer on one side (starting side of winding) in the circumferential direction of two first slots 21 separated by 5 slots.

[0018] 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 9 and the second layer of slot 14, the first layer of slot 33 and the second layer of slot 38, the third layer of slot 21 and the fourth layer of slot 26, the third layer of slot 45 and the fourth layer of slot 2, and the fifth layer of slot 33 and the sixth layer of slot 38, 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 21 and the second layer of slot 26, the first layer of slot 45 and the second layer of slot 2, the third layer of slot 33 and the fourth layer of slot 38, the fifth layer of slot 21 and the sixth layer of slot 26, and the fifth layer of slot 45 and the sixth layer of slot 2, as shown in FIG. 4.

[0019] 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 15 and the second layer of slot 20, the first layer of slot 39 and the second layer of slot 44, the third layer of slot 27 and the fourth layer of slot 32, the fifth layer of slot 15 and the sixth layer of slot 20, and the fifth layer of slot 39 and the sixth layer of slot 44. 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 27 and the second layer of slot 32, the third layer of slot 15 and the fourth layer of slot 20, the third layer of slot 39 and the fourth layer of slot 44, the fifth layer of slot 27 and the sixth layer of slot 32, and the fifth layer of slot 3 and the sixth layer of slot 8.

[0020] The pair of legs 40 of the second segment coil 4b 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 seven 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. 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 20 and the second layer of slot 27, the first layer of slot 44 and the second layer of slot 3, the third layer of slot 32 and the fourth layer of slot 39, the fifth layer of slot 20 and the sixth layer of slot 27, and the fifth layer of slot 44 and the sixth layer of slot 3, 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 8 and the second layer of slot 15, the first layer of slot 32 and the second layer of slot 39, the third layer of slot 20 and the fourth layer of slot 27, the third layer of slot 44 and the fourth layer of slot 3, and the fifth layer of slot 32 and the sixth layer of slot 39.

[0021] Furthermore, as shown in Figure 4, the pair of legs 40 of the second segment coil 4b that form the parallel coil U3 are inserted into the first layer of slot 26 and the second layer of slot 33, the third layer of slot 14 and the fourth layer of slot 21, the third layer of slot 38 and the fourth layer of slot 45, the fifth layer of slot 26 and the sixth layer of slot 33, as well as the fifth layer of slot 2 and the sixth layer of slot 9. Also, as shown in Figure 4, the pair of legs 40 of the second segment coil 4b that form the parallel coil U4 are inserted into the first layer of slot 14 and the second layer of slot 21, the first layer of slot 38 and the second layer of slot 45, the third layer of slot 26 and the fourth layer of slot 33, the fifth layer of slot 14 and the sixth layer of slot 21, as well as the fifth layer of slot 38 and the sixth layer of slot 45.

[0022] The pair of legs 40 of the third segment coil 4c 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 predetermined first and second slots 21 and 22 spaced 6 slots apart in the circumferential direction, and one of the pair of legs 40 forms the winding end portion in the 2·i layer or the winding start portion in the 2·i+1 (=2·(i+1)-1) layer. That is, the parallel coil U1 of the stator coil 3u includes two third segment coils 4c, and 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 9 and the fourth layer of slot 15, as shown in Figure 4, to form 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 8th slot and the sixth layer of the 14th slot, as shown in Figure 4, forming the starting point of the winding in the fifth layer (2·i+1 layer).

[0023] 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 8 and the fourth layer of slot 14, as shown in Figure 4, forming the winding start 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 9 and the sixth layer of slot 15, as shown in Figure 4, forming the winding start 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 first layer of slot 2 and the second layer of slot 8, as shown in Figure 4, forming the winding end in the second layer (2·i 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 third layer of the third slot and the fourth layer of the ninth slot, forming the end of the winding in the fourth layer (2·i layer). The parallel coil U4 of the stator coil 3u includes two third-segment coils 4c, and the pair of legs 40 of one of the third-segment coils 4c of the parallel coil U4 are inserted into the first layer of the third slot and the second layer of the ninth slot, forming the end of the winding in the second layer (2·i layer), as shown in Figure 4. Furthermore, the pair of legs 40 of the other third-segment coil 4c of the parallel coil U4 are inserted into the third layer of the second slot and the fourth layer of the eighth slot, as shown in Figure 4, forming the end of the winding in the fourth layer (2·i layer).

[0024] 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 Figures 4 and 5) relative to the first to third segment coils 4a, 4b, and 4c that form the parallel coils U1-U4 of the U phase, as shown in Figure 5. Furthermore, the first to third segment coils 4a, 4b, and 4c that form the parallel coils W1-W4 of the stator coil 3w are assembled with a 2-slot offset in the circumferential direction (to the left in Figures 4 and 5) relative to the first to third segment coils 4a, 4b, and 4c that form the parallel coils U1-U4 of the U phase, as shown in Figure 6.

[0025] As can be seen from Figures 4-6, 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 7 using a well-known ring arrangement device (see, for example, Patent Document 2).

[0026] 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 8, 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 in Figure 8, the first-to-third segment coils 4a, 4b, and 4c each include three types of segment coils with different spacings in the circumferential direction of a pair of legs 40.

[0027] 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 to opposite sides so that they are spaced apart from each other in the circumferential direction (see dashed lines in Figures 4-6). As can be seen from Figures 4-6, 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 six slots apart in the circumferential direction (for example, the second layer of slot 14 and the first layer of slot 20, etc.) are electrically joined together by welding (for example, laser welding, etc.).

[0028] As a result, multiple connecting wires 45 are formed on one end of the stator core 2, connecting the corresponding ends of the first and second segment coils 4a and 4b. As can be seen from Figures 4-6, the direction in which each connecting wire 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 wires 41 of the first to third segment coils 4a, 4b, and 4c cross layers on the other end of the stator core 2 (from layer 2·i-1 to layer 2·i). Prior to welding, the insulating coating is removed from the ends of each leg portion 40 so that the conductive material is exposed.

[0029] Furthermore, as shown in Figures 4-6, 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 6 slots apart (for example, the second layer of slot 3 and the third layer of slot 9, or the fourth layer of slot 2 and the fifth layer of slot 8), are twisted together and their tips are electrically joined by welding, so that the legs 40 of the third segment coil 4c that forms the winding end portion in the 2·i layer and the legs 40 of the third segment coil 4c that forms the winding start portion in the 2·i+1 layer are connected.

[0030] 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 9 or the fifth layer of slot 8 in Figure 4) on one side (winding start side) of the predetermined first and second slots 21, 22 (for example, slots 9 and 15, and slots 8 and 14 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 3 or the fourth layer of slot 2 in Figure 4, etc.) of slot 20 located 6 slots away from one of the predetermined first and second slots 21, 22 (for example, slot 9 or slot 8 in Figure 4, etc.) are twisted together so that the ends of both are electrically joined. Furthermore, at one end of the stator core 2, the legs 40 of the third segment coil 4c protruding from the 2·i layer (e.g., the second or fourth layer) of the other side (e.g., the eighth or ninth slot in Figure 4) opposite to one side (the winding start side) of the predetermined first and second slots 21, 22 (e.g., the second and eighth slots, and the third and ninth slots in Figure 4, etc.) are twisted together, and the legs 40 of the first or second segment coils 4a, 4b protruding from the 2·i+1 layer (e.g., the third layer of the 14th slot or the third layer of the 15th slot in Figure 4, etc.) of the slot 20 located six slots away from the other side of the predetermined first and second slots 21, 22 are twisted together, and their ends are electrically joined.

[0031] As a result, multiple connecting wires 47 are formed on one end of the stator core 2, each connecting the leg portion 40 of the third segment coil 4c that forms the winding end portion in layer 2·i to the leg portion 40 of the first or second segment coils 4a,4b that form the winding start portion in layer 2·i+1, and the connecting wires 47 that connect the leg portion 40 of the first or second segment coils 4a,4b that form the winding end portion in layer 2·i to the leg portion 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 9). As can be seen from Figures 4-6, 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 other connecting wires 45 (see the area enclosed by the double-dotted line in Figure 9) cross layers (from layer 2·i-1 to layer 2·i).

[0032] 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 and sixth layers of slots 8 and 9 are used as lead wires for 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 sixth layer of slots 2 and 3, and the first layer of slots 14 and 15, are used as neutral wires for parallel coils U1, U2, U3, and U4, as shown in Figure 4, and are electrically connected to the neutral point via a busbar unit (not shown).

[0033] Furthermore, the legs 40 inserted into the first and sixth layers of slots 12 and 13 are used as lead wires for 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 6 and 7, and the first layer of slots 18 and 19, are used as neutral wires for parallel coils V1, V2, V3, and V4, as shown in Figure 4, and are electrically connected to the neutral point via a busbar unit (not shown). Furthermore, the legs 40 inserted into the sixth layer of slots 4 and 5, and the first layer of slots 16 and 17, are used as lead wires for 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). Furthermore, the legs 40 inserted into the first and sixth layers of slots 10 and 11 are used as neutral wires for parallel coils W1, W2, W3, and W4, as shown in Figure 4, and are electrically connected to the neutral point 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 legs 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 of the stator core 2. In the stator 1, as can be seen from Figures 1 and 4-6, the legs 40 used as lead wires and neutral wires can be concentrated within a relatively narrow area of ​​the first coil end portion. This allows the stator 1 to be placed inside a case or the like so that the legs 40 used as lead wires and neutral wires are not submerged in the coolant (cooling oil) when the motor, including the stator 1, is cooled by the coolant (cooling oil). As a result, the stator 1 can significantly reduce the cost required for insulating the exposed conductor portions of the lead wires and neutral wires. Furthermore, in the multiple stator coils 3u, 3v, and 3w, the connecting wire portions 41 of the first to third segment coils 4a, 4b, and 4c form an annular second coil end portion that protrudes outward from the end face on the other end 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 of the stator 1 can be effectively suppressed.

[0035] As described above, the stator 1 includes a first segment coil 4a into which a pair of legs 40 are inserted into two first slots 21 spaced 5 slots apart, a second segment coil 4b into which a pair of legs 40 are inserted into two second slots 22 spaced 7 slots apart on both sides of the first slots 21, and a third segment coil 4c into which a pair of legs 40 are inserted into predetermined first and second slots 21,22 spaced 6 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 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. A 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 22 spaced 6 slots apart in the circumferential direction, forming the winding end portion in the 2·i layer or the winding start portion in the 2·i+1 layer. 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 22 spaced 6 slots apart in the circumferential direction are twisted so that their tips are joined together. Furthermore, 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 22 spaced 6 slots apart in the circumferential direction are twisted so that the winding end portion in the 2·i layer and the winding start portion in the 2·i+1 layer are connected, and their tips are joined together.

[0036] In other words, each parallel coil U1-U4, V1-V4, W1-W4 is formed by inserting a second segment coil 4b into two second slots 22 spaced seven slots apart, so as to straddle a first segment coil 4a inserted into two first slots 21 spaced five slots apart, and then joining the corresponding legs 40 at one end of the stator core 2 at a six-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), it becomes 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 coils U1-U4, V1-V4, W1-W4 in response to the passage of the rotor's magnets, within each parallel coil U1-U4, V1-V4, W1-W4, and suppress the flow of circulating current to the stator coils 3u, 3v, 3w.

[0037] 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 8 to slot 15, 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) (one each in slots 8 and 15, and two each in slots 9 and 14). Similarly, in the magnetic poles formed in the range from slot 20 to slot 27, the legs 40 are evenly distributed on both sides in the circumferential direction with respect to the magnetic pole center (two each in slots 20 and 27, and one each in slots 21 and 26). Furthermore, in the magnetic poles formed in the range from slot 32 to slot 39, the legs 40 are evenly distributed on both sides in the circumferential direction with respect to the magnetic pole center (one each in slots 32 and 39, and two each in slots 33 and 38). Furthermore, in the magnetic poles formed in the range from slot 44 to slot 3, 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 44 and 3, and one in slots 45 and 2). Therefore, in these magnetic poles, there is no timing difference in the generation of induced voltage in response to the passage of a magnet.

[0038] On the other hand, in the magnetic poles formed in the range from slot 14 to slot 21, the legs 40 are arranged with a bias to one side in the circumferential direction relative to the magnetic pole center (two in slots 14 and 20, and one in slots 15 and 21). Also, in the magnetic poles formed in the range from slot 38 to slot 45, the legs 40 are arranged with a bias to one side in the circumferential direction relative to the magnetic pole center (two in slots 38 and 44, and one in slots 39 and 45). 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. In contrast, in the magnetic poles formed in the range from slot 26 to slot 33, the legs 40 are arranged with a bias to the other side in the circumferential direction relative to the magnetic pole center (one in slots 26 and 32, and two in slots 27 and 33). Furthermore, in the magnetic poles formed in the range from slot 2 to slot 9, 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 2 and 8, and two each in slots 3 and 9). 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. Therefore, it can be understood that in parallel coil U1, the circulating current caused by the shift in the timing of the generation of induced voltage in the magnetic poles formed in the range from slot 14 to slot 21 and in the range from slot 38 to slot 45 can be canceled out with the circulating current caused by the shift in the timing of the generation of induced voltage in the magnetic poles formed in the range from slot 26 to slot 33 and in the range from slot 2 to slot 9. Then, in stator 1, similar to parallel coil U1, the circulating current due to the timing of the generation of induced voltage is canceled out within each parallel coil U2-U4, V1-V4, W1-W4.

[0039] 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, the first to third segment coils 4a, 4b, and 4c wound around the 2·i-1 and 2·i layers can be assembled to the stator core 2 after being arranged 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.

[0040] 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 protruding 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 protruding from the 2·i layer of slot 20 located 6 slots away from the other side of the predetermined first and second slots 21, 22 are twisted together so that their tips are joined, thereby forming a jumper wire portion 47. In other words, in the stator 1, the leg portion 40 of the third segment coil 4c that forms the winding end portion in layer 2·i or the winding start portion in layer 2·i+1, and the corresponding other leg portion 40 form a jumper portion 47 that spans the layers in the opposite direction to the other jumper portion 45. This allows each second segment coil 4b to be arranged in 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 a 6-slot pitch on one end of the stator core 2.

[0041] Furthermore, a portion of the leg portion 40 protruding from one end of the stator core 2 is used as a lead wire and 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, and 3w are connected by a Y connection, and a portion of the leg portion 40 protruding from one end of the stator core 2 is used as a neutral wire connected to the neutral point. This allows the lead wires and neutral wire 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 also 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 11.

[0042] 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, for example, either (10,4) or (12,8).

[0043] 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]

[0044] The invention disclosed herein can be used in industries such as stator manufacturing. [Explanation of symbols]

[0045] 1 Stator, 2 Stator core, 2o Center hole, 2t Teeth section, 20 Slot, 21 First slot, 22 Second slot, 3u Stator coil, 3v Stator coil, 3w Stator coil, 4 Segment coil, 4a First segment coil, 4b Second segment coil, 4c Third segment coil, 40 Leg section, 41, 45, 47 Connecting wire section, 42 Crank section, A Assembly, 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 five 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 seven 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 six slots apart in the circumferential direction, with the legs protruding from one end of the stator core, forming the winding end portion in the 2.i layer or the 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 six 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 six slots apart are twisted so that their tips are joined together.

2. In the stator according to claim 1, At one end of the stator core, the tip of the leg of the third segment coil that protrudes 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 that protrudes from the 2.i layer of the slot spaced 6 slots apart from one side of the predetermined first and second slots, are twisted so that their tips are joined together. A stator in which, at one end of the stator core, the leg portion of the third segment coil protruding from the other 2.i layer of the predetermined first and second slots opposite to the one side, and the leg portion protruding from the 2.i+1 layer of the slot located 6 slots away from the other side of the predetermined first and second slots, are twisted and their tips are 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 aforementioned multiple stator coils are connected by a Y-connection, 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 (6, 4), (10, 4), or (12, 8).

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