Stator and rotary electric machine

Abstract

To shorten the axial length of a coil end in a stator winding using a phase conductor of a rectangular wire.SOLUTION: A stator includes: a stator core in which a plurality of stator slots are formed on an inner peripheral face; and a stator winding including, for each phase, a plurality of coil segments 130 each of which has straight line parts 131x and 131y stored in two different stator slots by using a flat conductor and a connection part 132 for connecting the straight line parts on the outside of a first axial end of the stator core, and a plurality of crossover parts which connect in series the plurality of coil segments 130 on the outside of a second axial end of the stator core. The flat conductor of at least one connection part has thickness smaller than the flat conductor in the straight line parts 131x and 131y at a cross portion so that the two connection parts 132 can cross each other on the outside of the first axial end.SELECTED DRAWING: Figure 5

Description

Technical Field

[0001] Embodiments of the present invention relate to a stator and a rotating electrical machine.

Background Art

[0002] In motors and generators used in EVs (electric vehicles), PEVs (plug-in electric vehicles), etc., since a large current flows through the stator winding, a rectangular wire with a large cross-sectional area is used as the conductor of the stator winding. Therefore, since the connection unit including the rectangular wire becomes large-sized and causes interference with the peripheral components of the motor, a technique for compactly housing the connection unit near the motor is desired.

[0003] In view of such a situation, in a conventional rotating electrical machine, there is known a method of arranging rectangular wires in a plurality of axial layers axially outward in the axial direction of the coil end of the stator winding to make the connection unit compact.

[0004] FIG. 8 is a developed view showing a conventional example of the end portion of the stator winding of the stator. FIG. 8 shows the coil segments of the u-phase, v-phase, and w-phase in a partial angular region of one coil end portion of the stator.

[0005] Here, the coil segment includes a straight portion housed in two stator slots and a connection portion connecting the two straight portions. In FIG. 8, a case is shown where one straight portion is housed in the first layer in the stator slot and the other straight portion connected thereto is housed in the second layer in the stator slot. That is, the straight portions of the coil segment are housed in the first layer and the second layer. As shown in FIG. 8, the connection portions outside the straight portions housed in the first layer are arranged in parallel with each other. Similarly, the connection portions outside the straight portions housed in the second layer are arranged in parallel with each other. In the case of a total of six layers, the same applies between the third layer and the fourth layer, and further between the fifth layer and the sixth layer.

[0006] FIG. 9 is a wiring diagram showing a conventional connection state example of a stator winding. The horizontal direction in FIG. 9 indicates the slot numbers when consecutive numbers are assigned to the stator slots, and the vertical direction indicates the order of radial lamination in the stator slots. Signs such as 49u described in each cell indicate the numbers of the straight portions to which consecutive numbers of coil segments are assigned. The dashed line portions indicate connection portions that form coil segments outside one axial end of the stator core between two straight portions. Also, the solid line portions indicate crossover portions that connect coil segments to each other outside the other axial end of the stator core.

[0007] In FIG. 9, the u-phase portion of the stator winding is shown. The v-phase is obtained by shifting the slot numbers of the u-phase four by four to the right side in FIG. 9, and the w-phase is obtained by shifting the slot numbers of the u-phase eight by eight to the right side in FIG. 9.

[0008] In order to install these three-phase stator windings so that they do not interfere with each other outside the axial ends on both sides of the stator core, they have been conventionally arranged as follows.

[0009] (1) In the solid line portions, for example, the larger slot number of the first layer and the smaller slot number of the second layer are connected, and the connections are parallel to each other. The same applies to between the third layer / fourth layer and between the fifth layer / sixth layer. That is, the crossover portions between coil segments connect the odd layers and the even layers of different stator slots so as to be parallel to each other.

[0010] (2) In the dashed line portions, for example, the smaller slot number of the second layer and the larger slot number of the first layer are connected, and the connections are parallel to each other. The same applies to between the third layer / fourth layer and between the fifth layer / sixth layer. That is, the connection portions of coil segments connect the odd layers and the even layers of different stator slots so as to be parallel to each other.

[0011] (3) The intervals between slots are the same as the interval of the full-pitch winding on both the solid line side and the dashed line side.

Prior Art Documents

Patent Document

[0012]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0013] As described above, when winding using a flat wire with a rectangular cross - section as a phase conductor, even when the number of slots per pole per phase is greater than 1, a full - pitch winding with a winding pitch of one pole is used. However, in a full - pitch winding, since the winding pitch is long, the length of the winding becomes long. As a result, there is a problem that the conductor resistance increases and the efficiency of the rotating electrical machine decreases. Also, since the pitch is long, there is a problem that the axial length of the coil end becomes long.

[0014] An object of the present invention is to provide a stator and a rotating electrical machine that can shorten the axial length of the coil end of the stator winding using a flat wire as a phase conductor and can be miniaturized.

Means for Solving the Problems

[0015] To achieve the above object, a stator according to an embodiment of the present invention is arranged via a gap on the radially outer side of a rotor that extends in the axial direction and rotates around the rotation center axis in a rotating electrical machine. The stator includes a stator core having a plurality of stator slots formed at intervals in the circumferential direction on the inner peripheral surface, and a plurality of coil segments each having a straight portion accommodated in two different ones of the stator slots using a flat conductor and a connecting portion connecting the two straight portions outside the first axial end of the stator core. The stator winding includes a plurality of connecting portions that connect the plurality of coil segments in series outside the second axial end of the stator core. The flat conductor of at least one of the connecting portions has a thickness smaller than that of the flat conductor in the straight portion at the crossing portion so that the two connecting portions can cross outside the first axial end.

Brief Description of the Drawings

[0016]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Embodiment for Carrying Out the Invention

[0017] Hereinafter, with reference to the drawings, a stator and a rotating electrical machine according to an embodiment of the present invention will be described. Here, the same or similar parts are denoted by common reference numerals, and redundant descriptions are omitted.

[0018] [First Embodiment] FIG. 1 is a longitudinal sectional view showing a rotating electrical machine 1 according to the first embodiment. FIG. 2 is a cross-sectional view showing the rotating electrical machine according to the first embodiment. Further, FIG. 3 is a partial cross-sectional view for explaining the accommodation of the stator winding 120 in the stator slot 111 of the stator 100 according to the first embodiment. FIG. 3 shows the details of part A in FIG. 2.

[0019] As shown in FIG. 1, the rotating electrical machine 1 includes a rotor 10, a stator 100, two bearings 21, two bearing brackets 22, and a frame 23.

[0020] The rotor 10 has a rotor shaft 11 extending in the direction of the rotation axis CL and rotatably supported by two bearings 21, a rotor core 12 attached to the outer side in the radial direction of the rotor shaft 11, and a plurality of permanent magnets 13 housed in the rotor core 12. Note that in FIGS. 1 to 3, an example using a permanent magnet type rotor is shown, but a synchronous machine or an induction machine using a wound type rotor, or an induction machine using a rotor having conductor bars may also be used.

[0021] The stator 100 is housed in the frame 23 and has a stator core 110 and a stator winding 120 wound around the stator core 110.

[0022] As shown in FIGS. 2 and 3, the stator core 110 has a plurality of stator slots 111 formed at intervals in the circumferential direction, and stator teeth 112 each formed by adjacent stator slots 111.

[0023] As shown in FIG. 1, the stator winding 120 has a plurality of coil segments 130 and a connecting portion 125 connecting them. Each coil segment 130 has two straight portions 131 having portions housed in the stator slots 111 and a connecting portion 132 connecting them.

[0024] The two straight portions 131 of each coil segment 130 are inserted into the stator slots 111 from the side of the first end portion 110a of the stator core 110, respectively. Each straight portion 131 protruding from the side of the second end portion 110b is bent and connected by the connecting portion 125. Therefore, the connecting portion 132 of each coil segment 130 is arranged axially outside the first end portion 110a, and each connecting portion 125 is arranged axially outside the second end portion 110b.

[0025] Hereinafter, the portion axially outside the first end portion 110a of the stator winding 120 is referred to as the first coil end portion 120a, and the portion axially outside the second end portion 110b of the stator winding 120 is referred to as the second coil end portion 120b. Specifically, the first coil end portion 120a is the connecting portion 132 of the coil segment 130 and the portion outside the first end portion 110a of the straight portion 131. The second coil end portion 120b is the straight portion outside the second end portion 110b of the straight portion 131 of the coil segment 130 and the connecting portion 125 connected thereto.

[0026] As shown in FIG. 3, in each slot, the straight portions 131a, 131b, 131c, 131d, 131e, 131f of different coil segments are housed so as to be laminated in the radial direction. Hereinafter, from the radially outer side toward the radially inner side, that is, from the radial position where the straight portion 131a is housed to the radial position where the straight portion 131f is housed, they are sequentially referred to as the first layer to the sixth layer.

[0027] FIG. 4 is a developed view showing the end portion of the stator winding 120 of the stator 100 according to the first embodiment. Specifically, it is a developed view seen from the radially outer side. Further, FIG. 5 is a cross-sectional view showing the end portion of the stator winding 120 of the stator 100 according to the first embodiment, and is a cross-sectional view taken along the line A-A of FIG. 4.

[0028] Here, FIG. 4 shows the coil segments 130 of the u-phase, v-phase, and w-phase in a partial angular region of one coil end portion 120a of the stator 100. Further, in FIG. 4, a portion of one layer in the first coil end portion 120a is shown. Further, FIG. 5 shows one coil segment 130 among the first coil end portions 120a shown in FIG. 4.

[0029] As shown in FIG. 5, the coil segment 130 has a first straight portion 131x, a second straight portion 131y, and a connecting portion 132 connecting these. Further, the connecting portion 132 has a connecting portion first region 132x and a connecting portion second region 132y. In the connecting portion first region 132x, a thickness reduction portion 132d is formed on the radially outer surface. Further, in the connecting portion second region 132y, a thickness reduction portion 132d is formed on the radially inner surface. As a result, a stepped portion 132s is formed between the connecting portion first region 132x and the connecting portion second region 132y.

[0030] Here, the straight line of the portion where the thickness reduction portion 132d is formed is formed thinner than the thickness of the straight lines 131x and 131y. The straight line of the portion where the thickness reduction portion 132d is formed is, for example, half of the thickness of the straight lines 131x and 131y. Thereby, when they cross each other, they can be arranged in the same arrangement as in the conventional case. Note that the arrangement is also established even if it is larger than half of the thickness of the straight lines 131x and 131y, but in order to arrange them in the same arrangement as in the conventional case, about half of the thickness of the straight lines 131x and 131y is preferable.

[0031] As a method of forming a thickness reduction portion 132d in the straight conductor, that is, reducing the thickness of the straight conductor, methods such as reducing the thickness of the straight conductor by pressing or the like before the insulating film treatment, reducing the thickness by removing the thickness reduction portion 132d from the straight conductor, reducing the thickness by pressing or the like in the state after the insulating film treatment, and connecting thin straight conductors may be used.

[0032] In the first coil end portion 120a in the present embodiment in which the coil segment 130 formed in this way is arranged, it is arranged as follows.

[0033] (1) Different from the conventional example shown in FIG. 8, in each coil segment 130, the first straight portion 131x and the second straight portion 131y are accommodated in the same nth layer.

[0034] (2) The coil segments 130 of the u-phase, v-phase, and w-phase are arranged at the same radial position in the nth layer.

[0035] In this way, by forming the thickness reduction portion 132d at the portion where the connection portions 132 cross each other, it is possible to make them cross while maintaining the same radial position in the nth layer.

[0036] FIG. 6 is a wiring diagram showing an example of the connection state of the stator winding 120 of the stator 100 according to the first embodiment.

[0037] The horizontal direction in FIG. 6 indicates the slot number when consecutive numbers are assigned to the stator slots 111, and the vertical direction indicates the order of radial lamination in the stator slots 111. Signs such as 1u described in each cell indicate the numbers of the straight portions 131 to which consecutive numbers of the coil segments 130 are assigned.

[0038] The broken line portion indicates the connection portion 132 that forms the coil segment 130 outside one first end portion 110a of the stator core 110 between two straight portions 131.

[0039] The solid line portion indicates a connecting portion 125 that connects coil segments 130 to each other outside the other second end 110b of the stator core 110.

[0040] In FIG. 6, the u-phase portion of the stator winding 120 is shown. The v-phase is obtained by shifting the slot numbers of the u-phase four by four to the right side of the figure in FIG. 6, and the w-phase is obtained by shifting the slot numbers of the u-phase eight by eight to the right side of the figure in FIG. 6.

[0041] The stator winding 120 in this embodiment is configured as follows as shown in FIG. 6.

[0042] (1) The connecting portion 132 of the broken line portion, that is, the first coil end portion 120a, connects the first layer to the first layer and the sixth layer to the sixth layer. Also, the interval between the stator slots 111 is a short-pitch winding that is one slot shorter than in the conventional example.

[0043] (2) The connecting portion 125 of the solid line portion, that is, the second coil end portion 120b, connects, for example, the one with the larger slot number in the first layer and the one with the smaller slot number in the second layer, and the connections are parallel to each other. The same applies between the second layer and the third layer, between the third layer and the fourth layer, between the fourth layer and the fifth layer, and between the fifth layer and the sixth layer.

[0044] (3) In the connecting portion 132, for example, the one with the smaller slot number in the second layer and the one with the larger slot number in the third layer are connected, and the connections are parallel to each other. The same applies between the second layer and the third layer, between the third layer and the fourth layer, between the fourth layer and the fifth layer, and between the fifth layer and the sixth layer.

[0045] (4) Both the connecting portion 132 and the connecting portion 125 are short-pitch windings with an interval between slots that is one slot shorter than before.

[0046] As described above, in the present embodiment, by using a flat angle wire in which a thickness reduction portion 132d is formed at the intersection in the connecting portion 132 and the bridging portion 125, that is, a flat angle wire with a small thickness, the stator winding 120 having a short coil turn portion can be realized, and the length of the stator winding 120 can be shortened. As a result, the conductor resistance of the stator winding 120 can be reduced to improve the efficiency, the axial length of the coil end portion can be shortened, and miniaturization can be achieved.

[0047] [Second Embodiment] FIG. 7 is a wiring diagram showing an example of the connection state of the stator winding 120 of the stator 100 according to the second embodiment. Since the description method of FIG. 7 is the same as that of FIG. 6 described above, the description is omitted.

[0048] The stator winding 120 in the present embodiment is configured as follows as shown in FIG. 7.

[0049] (1) The connecting portion 132 of the broken line portion, that is, the first coil end portion 120a, connects the first layer to the first layer, the second layer to the second layer, the third layer to the third layer, the fourth layer to the fourth layer, the fifth layer to the fifth layer, and the sixth layer to the sixth layer. Also, the interval between the stator slots 111 is a short coil turn that is one slot shorter than the conventional example. Here, a flat angle wire having a portion where the thickness reduction portion 132d is formed is used.

[0050] (2) The bridging portion 125 of the solid line portion, that is, the second coil end portion 120b, connects the one with the larger slot number in the first layer and the one with the smaller slot number in the second layer, and the connections are parallel to each other. The same applies between the third layer and the fourth layer, and between the fifth layer and the sixth layer.

[0051] (3) The solid line side connects the one with the smaller slot number in the second layer and the one with the larger slot number in the third layer, and the connections are parallel to each other. The same applies between the fourth layer and the fifth layer.

[0052] (4) The solid line side is a full coil turn.

[0053] As described above, also in this embodiment, by using a flat wire in which a thickness reduction portion 132d is formed at the intersection in the connecting portion 132, that is, a flat wire having a small thickness, the stator winding 120 having a short pitch winding portion can be realized, and the length of the stator winding 120 can be shortened. As a result, the conductor resistance of the stator winding 120 can be reduced to improve the efficiency, the axial length of the coil end portion can be shortened, and miniaturization can be realized.

[0054] According to the embodiment described above, it is possible to provide a stator and a rotating electric machine that can reduce the conductor resistance of the stator winding using a flat wire phase conductor to improve the efficiency, shorten the axial length of the coil end, and enable miniaturization.

[0055] [Other Embodiments] Although the embodiments of the present invention have been described above, the embodiments are presented as examples and are not intended to limit the scope of the invention. Also, the features of each embodiment may be combined. Furthermore, the embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the gist of the invention. The embodiments and their modifications are included in the scope and gist of the invention, and are also included in the invention described in the claims and the equivalent scope thereof. [Description of Reference Numerals]

[0056] 1…Rotating electrical machine, 10…Rotor, 11…Rotor shaft, 12…Rotor core, 13…Permanent magnet, 21…Bearing, 22…Bearing bracket, 23…Frame, 100…Stator, 110…Stator core, 110a…First end, 110b…Second end, 111…Stator slot, 120…Stator winding, 120a…First coil end portion, 120b…Second coil end portion, 125…Crossing portion, 130…Coil segment, 131…Straight portion, 131a…First layer storage portion, 131b…Second layer storage portion, 131c…Third layer storage portion, 131d…Fourth layer storage portion, 131e…Fifth layer storage portion, 131f…Sixth layer storage portion, 131x…First straight portion, 131y…Second straight portion, 132…Connection portion, 132d…Thickness reduction portion, 132x…Connection portion first region, 132y…Connection portion second region, 132s…Step portion, 141…Lead wire, 142…Neutral point wire

Claims

1. In a rotating electrical machine, a stator core disposed via a gap on the radially outer side of a rotor that extends in the axial direction and rotates around a rotation center axis, and a plurality of stator slots are formed at intervals in the circumferential direction on the inner peripheral surface; A plurality of coil segments each having a straight portion accommodated in two different ones of the stator slots using a flat conductor and a connecting portion connecting the two straight portions outside the first axial end of the stator core, and a plurality of bridging portions connecting the plurality of coil segments in series outside the second axial end of the stator core; provided with; At a first intersection portion so that the two connecting portions can intersect outside the first axial end, the flat conductor of at least one of the connecting portions has a thickness smaller than that of the flat conductor in the straight portion. A stator characterized by this.

2. At the first intersection portion, the flat conductors of both intersecting connecting portions have a thickness of half that of the flat conductor in the straight portion. The stator according to claim 1, characterized by this.

3. At a second intersection portion so that the two bridging portions can intersect outside the second axial end, the flat conductor of at least one of the bridging portions has a thickness smaller than that of the flat conductor in the straight portion. The stator according to claim 1, characterized by this.

4. At the second intersection portion, the flat conductors of both intersecting bridging portions have a thickness of half that of the flat conductor in the straight portion. The stator according to claim 3, characterized by this.

5. The stator according to any one of claims 1 to 4, characterized in that the stator winding has a short-pitch winding portion.

6. A rotor, A stator according to any one of claims 1 to 4 disposed radially outside the rotor, A rotating electrical machine characterized by comprising the same.

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