Stator and rotary electrical machine

Abstract

According to an embodiment, a stator (100) comprises a stator core and a stator winding (120). The stator winding (120) comprises, for each phase, a phase conductor (121) comprising coil segments (130) and a segment connection portion (128) connecting the coil segments (130) in series, each coil segment (130) using a flat conductor and having a bridge portion and a straight line portion (131) accommodated in two stator slots (111), the phase conductor (121) leading from a lead wire connection portion (141) to a neutral point wire connection portion (142). The phase conductor (121) has a parallel portion (123) and a non-parallel portion (122). The non-parallel portion (122) is laid over the entire circumference in the circumferential direction M times (M is an integer of 2 or more) in every two layers from the outside in the radial direction, and the parallel portion (123) is laid thereover a number of times less than M.

Description

Stator and rotating electric machine

[0001] An embodiment of the present invention relates to a stator and a rotating electric machine.

[0002] In electric motors and generators used in EVs (electric vehicles), PEVs (plug-in electric vehicles), and the like, a large current flows through the stator windings, and therefore rectangular wires with large cross-sectional areas are used as the conductors of the stator windings.

[0003] In recent years, rotating electrical machines have become faster and operate at higher frequencies. This has led to a problem of AC copper loss in rectangular wires. To address this issue, a technique has been developed to split the inner conductor and transpose them into parallel circuits.

[0004] Patent No. 7186927

[0005] If the above-mentioned technology is used, the connections on the inner and outer peripheries become complicated, posing a problem in terms of manufacturability.

[0006] An object of the present invention is to provide a stator and a rotating electric machine that reduce the complexity of a stator winding having a transposed parallel portion.

[0007] In order to achieve the above-mentioned object, the stator according to this embodiment comprises a cylindrical stator core having a plurality of axially extending stator slots formed on its inner peripheral surface at intervals in the circumferential direction, a plurality of coil segments using flat rectangular conductors, each having a straight portion accommodated in two different stator slots and a bridging portion connecting the two straight portions outside a first end of the stator core in the axial direction, and a plurality of segment connection portions connecting the plurality of coil segments in series outside a second end of the stator core in the axial direction, the phase conductors extending from a lead wire connection portion connecting to an external lead wire to a neutral wire connection portion connecting to a neutral point, and a stator winding provided for each phase, wherein the plurality of straight portions form N layers (N is an even number of 4 or more) from the radially outer side, namely, a first layer to an Nth layer, in each of the plurality of stator slots, and the phase conductor has a parallel portion in which a first portion and a second portion arranged in two layers, the Nth layer and the (N-1)th layer on the inner circumferential side, are connected in parallel to each other, and non-parallel portions of the phase conductor excluding the parallel portion are laid M times (M is an integer of 2 or more) around the entire circumference in the radially outer two layers, and the parallel portion is laid fewer than M times around the entire circumference in the circumferential direction.

[0008] 1 is a longitudinal cross-sectional view showing an example of the configuration of a rotating electric machine according to a first embodiment; a cross-sectional view of a rotor and a stator showing an example of the configuration of a rotating electric machine according to the first embodiment; a partial cross-sectional view of a rotor and a stator showing how the stator winding is housed in the stator according to the first embodiment; a connection diagram showing how the straight portions of each layer in each slot of the stator winding of the stator according to the first embodiment are connected; a connection diagram showing how the straight portions of each layer in each slot of the stator winding of the stator according to the first embodiment are connected; a connection diagram showing an example of how the straight portions of each layer in each slot of a conventional stator winding for comparison are connected; a partial cross-sectional view of a rotor and a stator showing how the stator winding is housed in a stator according to a second embodiment; a connection diagram showing how the straight portions of each layer in each slot of the stator winding of the stator according to the second embodiment are connected; a connection diagram showing how the straight portions of each layer in each slot of the stator winding of the stator according to the second embodiment are connected; a connection diagram showing how the straight portions of each layer in each slot of the stator winding of the stator according to the second embodiment are connected; Fig. 10 is a connection diagram showing the connection state between straight portions of each layer in each slot of a stator winding of a stator according to a third embodiment. Fig. 11 is a connection diagram showing the connection state between straight portions of each layer in each slot of a stator winding of a stator according to a fourth embodiment. Fig. 12 is a connection diagram showing the connection state between straight portions of each layer in each slot of a stator winding of a stator according to the fourth embodiment.

[0009] Hereinafter, a stator and a rotating electrical machine according to an embodiment of the present invention will be described with reference to the drawings. Here, the same or similar parts are denoted by the same reference numerals, and overlapping descriptions will be omitted.

[0010] First Embodiment FIG. 1 is a cross-sectional view showing an example of the configuration of a rotating electrical machine 1 having a stator 100 according to an embodiment.

[0011] The rotating electric machine 1 includes a rotor 10 , a stator 100 , a bearing 21 , a bearing bracket 22 , and a frame 23 .

[0012] The rotor 10 has a rotor shaft 11 extending in a direction (axial direction) parallel to the direction of extension of the rotation axis CL, a rotor core 12 attached radially outside the rotor shaft 11, and permanent magnets 13 arranged in the rotor core 12. Note that while Fig. 1 illustrates a permanent magnet type synchronous machine as an example of the rotor 10, it may be a wound type or an induction type rotor. Hereinafter, the radial direction refers to the direction radially away from the rotation axis CL in a cross section perpendicular to the rotation axis CL, and the circumferential direction refers to the direction in which any part in the rotating body moves.

[0013] The stator 100 has a cylindrical stator core 110 provided radially outside the rotor core 12 , and a stator winding 120 wound around the stator core 110 .

[0014] The stator winding 120 is a winding using a rectangular conductor insulated with, for example, enamel. The stator winding 120 forms a multi-phase, e.g., three-phase, circuit. Each phase of the stator winding has a phase conductor 121 extending from a lead wire connection 141 (FIG. 4) that connects to an external lead wire to a neutral wire connection 142 (FIG. 4) that connects to a neutral point. The phase conductor 121 of each phase of the stator winding 120 has a plurality of coil segments 130 and segment connection portions 128 that connect the coil segments 130 together.

[0015] Each coil segment 130 has two straight portions 131 and a bridge portion 132 connecting these two straight portions 131. The straight portions 131 pass through the interior of the stator slots 111 formed in the stator core 110. The bridge portion 132 of each coil segment 130 is disposed axially outside the first end 110a of the stator core 110. Furthermore, the ends of each of the two straight portions 131 that are not connected to the bridge portion 132 protrude outside the second axial end 110b of the stator core 110. The two straight portions 131 are connected to other coil segments 130 by segment connection portions 128 outside the second end 110b. Here, the segment connection portions 128 are, for example, welded or brazed portions. It should be noted that the straight portion 131 on the outside of the second end 110b has a shape that follows the circumferential direction and is not linear, but in the following explanation, for convenience, this portion will not be distinguished and will be referred to as the straight portion 131.

[0016] FIG. 2 is a cross-sectional view of the rotor 10 and the stator 100 showing an example of the configuration of the rotating electric machine 1 according to the first embodiment.

[0017] A plurality of stator slots 111 are formed in the stator core 110 at intervals in the circumferential direction. Adjacent stator slots 111 form stator teeth 112. Straight portions 131 of the coil segments 130 are housed in each stator slot 111 so as to be stacked in the radial direction.

[0018] The rotor 10 shown in Fig. 2 has two permanent magnets 13 housed in each magnetic pole within a rotor core 12 attached to the radial outside of a rotor shaft 11. Note that the rotor 10 shown in Fig. 2 is an example, and the stator 100 and rotating electric machine 1 according to this embodiment can also be applied to rotors of other types.

[0019] 3 is a partial cross-sectional view showing the state of the straight portion 131 in the stator slot 111 of the stator 100 according to the first embodiment. FIG. 3 shows the details of part A in FIG.

[0020] A plurality of stator slots 111, which are axial through-grooves extending in the axial direction and spaced apart from one another in the circumferential direction, are formed on the radial inner peripheral surface of the stator core 110. The stator slots 111 are formed adjacent to one another in the circumferential direction, thereby forming stator teeth 112, respectively.

[0021] In each stator slot 111, a plurality of rectangular conductors with rectangular cross sections, which form the straight portions 131 of the coil segments 130, are stacked radially while being electrically insulated from one another. When the phase conductors 121 (FIG. 1) of the stator winding 120 are formed by the coil segments 130 and the segment connection portions 128 (FIG. 1), the number N of laminations of the straight portions 131 stacked in each stator slot 111 is an even number. In this embodiment, N is an even number equal to or greater than 4. The following description will be given taking the case where N is 6 as an example.

[0022] In the example shown in Fig. 3, the first layer conductor 131a, the second layer conductor 131b, the third layer conductor 131c, the fourth layer conductor 131d, the fifth layer conductor 131e, and the sixth layer conductor 131f are arranged in each stator slot 111 from the outside to the inside in the radial direction. That is, in this case, the number of laminations N is 6. Hereinafter, regardless of the stator slot 111, these flat rectangular conductors that make up the straight portion 131 will be referred to as the nth layer conductor (n = 1 to N) in accordance with the layer order. In the example shown in Fig. 2, the first layer conductor 131a, the second layer conductor 131b, the third layer conductor 131c, the fourth layer conductor 131d, the fifth layer conductor 131e, and the sixth layer conductor 131f are arranged in this order.

[0023] The radial thicknesses t0 of the first layer conductor 131a, the second layer conductor 131b, the third layer conductor 131c, and the fourth layer conductor 131d are substantially the same. Meanwhile, the radial thickness t1 of the fifth layer conductor 131e and the sixth layer conductor 131f, which correspond to the parallel portion 123 (FIG. 5) described below, is substantially half of t0. Furthermore, within the range of the parallel portion 123, not only the thickness of the straight portion 131 but also the thickness of the bridging portion 132 and the segment connection portion 128 is half of t0. In other words, the parallel portion 123 is disposed on the Nth layer and the (N-1)th layer, and the example shown in FIG. 3 shows a case where the number of stacked layers N is 6.

[0024] Here, "substantially the same" means that the dimensions are the same in design and match within the range of manufacturing tolerances, and "t1 is substantially half" of t0 also means that t1 is half of t0 in design and becomes half within the range of manufacturing tolerances. Here, manufacturing tolerances include errors in processing, assembly, measurement, etc.

[0025] Fig. 4 is a connection diagram showing the connection state between the straight portions 131 of each layer in each stator slot 111 of the stator winding 120 of the stator 100 according to the first embodiment. Fig. 5 is a connection diagram showing the connection state between the straight portions 131 of each layer in each stator slot 111 of the stator winding 120 of the stator 100 according to the first embodiment.

[0026] 4 and 5 illustrate an example in which there are three phases, eight poles, and two slots per pole per phase, for a total of 48. In the case of full-pitch winding, one pole corresponds to six slots. Therefore, a shift of one pole corresponds to a shift of six slots. While FIG. 5 shows the configuration of the U phase, the V and W phases have similar configurations.

[0027] 4 shows the U-phase conductor 121. The V-phase is shifted from the U-phase by four slots, and the W-phase is shifted from the U-phase by eight slots.

[0028] 4, dashed lines indicate bridge portions 132 of coil segments 130, or portions outside the first end 110a of the stator 100. Both ends of the bridge portions 132 indicate straight portions 131 housed in the corresponding layers of the stator slots 111. Solid lines indicate portions outside the second end 110b of the stator 100, including the segment connection portions 128.

[0029] 4 and 5 , the U-phase phase conductor 121 starts from the radially outermost lead wire connection portion 141, extends radially inward, and then extends radially outward again to reach the neutral wire connection portion 142. The numbers 1u to 80u are consistent numbers that indicate the connection order of the straight portions 131.

[0030] As shown in Fig. 5, the phase conductor 121 of each phase has a non-parallel portion 122 and a parallel portion 123. The phase conductor 121 of each phase has the non-parallel portion 122 wound radially inward from the outermost layer between the first and second layers or between the (N-3)th and (N-2)th layers, and then connected to the parallel portion 123. Here, as described above, in the case of Fig. 5, N is 6, so the (N-3)th and (N-2)th layers are the third and fourth layers.

[0031] The parallel portion 123 is inverted in the innermost layer. The period up to this point is called the outward path. The period after the inversion is called the return path. After the parallel portion 123 is inverted in the innermost layer, it is wound in the opposite circumferential direction. Then, the parallel portion 123 is connected to the non-parallel portion 122. The non-parallel portion 122 is wound in the opposite circumferential direction toward the radially outer side.

[0032] In each of the forward and backward passes, the number of times that the non-parallel portion 122 is wound in the circumferential direction between each two layers is set to M times (M is an integer of 2 or more). Also, the number of times that the parallel portion 123 is wound in the circumferential direction between each two layers is set to M times. Ｐ times (M Ｐ is an integer). In this case, M Ｐ is smaller than M.

[0033] The details of the route and configuration between these will be explained below. Ｐ is 1 and N is 6 as described above.

[0034] The paths will be explained using the numbers of the straight line sections 131. The numbers shown in the figure will be used for the straight line sections 131. In Figure 5, the right side of the wiring diagram indicates which layer each part of the phase conductor 121 is arranged on.

[0035] <Regarding the non-parallel portion> First, from straight portion 1u connected to lead wire connection portion 141 to straight portion 8u, it makes one circumferential turn while crossing between the first and second layers. During this time, it extends while being shifted by one pole in the circumferential direction, i.e., six slots. Furthermore, from the next straight portion 9u to straight portion 16u, it also makes one circumferential turn while crossing between the first and second layers. As a result, from straight portion 1u to straight portion 16u, it makes two circumferential turns while crossing between the first and second layers.

[0036] Next, the straight line portion 17u connected to the straight line portion 16u to the straight line portion 32u also makes two turns in the circumferential direction while crossing between the third and fourth layers.

[0037] The straight line portions 1u to 32u are connected in series to form the non-parallel portion 122. The straight line portion 32u arranged on the fourth layer is then connected to the parallel portion 123. That is, the straight line portions 1u to 32u form the outward path of the non-parallel portion 122, extending from the lead wire connection portion 141 to the connection portion with the parallel portion 123.

[0038] The return path of the non-parallel section 122 is the section from the straight section 49u to the straight section 80u. The straight section 49u is connected to the end of the parallel section 123 and is housed in the fourth layer of the first slot. The straight section 80u is housed in the first layer of the sixth slot and is connected to the neutral conductor connection section 142.

[0039] In the return path portion of the non-parallel section 122, the section from the straight line section 49u to the straight line section 64u makes two circumferential turns while crossing between the fourth and third layers, and the section from the straight line section 65u to the straight line section 80u makes two circumferential turns while crossing between the second and first layers. However, the outward path portion and the return path portion of the non-parallel section 122 are oriented in opposite directions in the circumferential direction.

[0040] <Parallel Section> The parallel section 123 has a first section 123a and a second section 123b that are electrically connected in parallel to each other. The first section 123a will be described below. Here, the first section 123a and the second section 123b each have a forward section from the straight section 33u to the straight section 40u and a return section from the straight section 41u to the straight section 48u after turning back.

[0041] <First Portion> The first portion 123a starts from the straight portion 33u housed in the fifth layer of the 48th stator slot 111 that connects to the straight portion 32u.

[0042] The first portion 123a extends circumferentially across the fifth and sixth layers. The two straight portions 131 of the coil segment 130 alternately alternate between being offset from each other by one pole plus one slot and one pole minus one slot in the circumferential direction. The connection between these portions is indicated by the straight portions 131 at both ends of the bridge portion 132 shown by the dashed line in Figure 4 .

[0043] Note that, in the illustrated example, the straight portions 131 of the coil segments 130 of the first portion 123a alternate between being offset from each other in the circumferential direction by one pole plus one slot and being offset from each other by one pole minus one slot, but this is not limiting. It is also possible for the straight portions 131 of the coil segments 130 to alternate at least one of the cases where they are offset from each other in the circumferential direction by one pole plus one slot and the case where they are offset from each other by one pole minus one slot, to occur one or more times. Similarly, for the second portion 123b described below, it is also possible for the straight portions 131 of the coil segments 130 to alternate at least one of the cases where they are offset from each other in the circumferential direction by one pole plus one slot and the case where they are offset from each other by one pole minus one slot, to occur one or more times.

[0044] For example, in the first coil segment 130, one straight portion 33u is housed in the fifth layer of the 48th stator slot 111, and the other straight portion 34u is housed in the sixth layer of the seventh stator slot 111. The 48th and seventh stator slots 111 are offset by seven slots, i.e., one pole plus one slot.

[0045] Looking at the next coil segment 130, one straight portion 35u is housed in the fifth layer of the thirteenth stator slot 111, and the other straight portion 36u is housed in the sixth layer of the eighteenth stator slot 111. The thirteenth and eighteenth stator slots 111 are offset by five slots, i.e., one pole minus one slot.

[0046] After arranging the four coil segments 130 in this manner, the circumferential direction is reversed, and then four more coil segments 130 are arranged in the same manner. Then, they are connected to the straight portion 49u of the non-parallel portion 122. Here, the straight portion 49u is housed in the fourth layer of the first slot of the stator slots 111.

[0047] As described above, the first portion 123a of the parallel portion 123 has eight coil segments 130. In the straight portions 131 of four of the eight coil segments 130, one of the coil segments 130 is offset from the other by one pole plus one slot. In other words, these four coil segments 130 are long coil segments. In addition, in the straight portions 131 of another four of the eight coil segments 130, one of the coil segments 130 is offset from the other by one pole minus one slot. In other words, these four coil segments 130 are short coil segments.

[0048] Thus, the first portion 123a of the parallel portion 123 has four long segments and four short segments, and the long segments and the four short segments are arranged alternately.

[0049] Next, the second portion 123b of the parallel portion 123 will be described. Each straight portion 131 in the second portion 123b is indicated by the same number as the corresponding straight portion 131 in the first portion 123a. As shown in FIG. 5 , the arrangement of each straight portion 131 in the second portion 123b is the same as the arrangement of the corresponding straight portions 131 in the first portion 123a. The second portion 123b is also similar to the first portion 123a in that it has four long segments and four short segments, with the long segments and four short segments arranged alternately.

[0050] The second portion 123b differs from the first portion 123a in the order of the long and short segments, i.e., the second portion 123b starts with the short segments.

[0051] <Second Part> The second part 123b will be described in detail below, focusing on the differences from the first part 123a.

[0052] One straight portion 33u of the first coil segment 130 of the second portion 123b is housed in the fifth layer of the first stator slot 111, and the other straight portion 34u is housed in the sixth layer of the sixth stator slot 111. In other words, the first coil segment 130 is a short coil segment.

[0053] Looking at the next coil segment 130 of the second portion 123b, one straight portion 35u is housed in the fifth layer of the twelfth stator slot 111, and the other straight portion 36u is housed in the sixth layer of the nineteenth stator slot 111. The twelfth and nineteenth stator slots 111 are offset by seven slots, i.e., one pole plus one slot. In other words, the next coil segment 130 is a long coil segment.

[0054] <Relationship Between First Portion and Second Portion> Here, the relationship between the coil segments 130 of the first portion 123a and the coil segments 130 of the second portion 123b will be further explained below.

[0055] First, the relationship between the respective first coil segments 130 will be described.

[0056] The first coil segment 130 of the first portion 123a has a straight portion 33u that is housed in the fifth layer of the 48th stator slot 111 and a straight portion 34u that is housed in the sixth layer of the seventh stator slot 111. The first coil segment 130 of the second portion 123b has a straight portion 33u that is housed in the fifth layer of the first stator slot 111 and a straight portion 34u that is housed in the sixth layer of the sixth stator slot 111.

[0057] As a result, the first coil segment 130 of the first portion 123a is arranged along the first coil segment 130 of the second portion 123b and outside the first coil segment 130 of the second portion 123b on the axial outside of the first end 110a of the stator core 110. This means that the first coil segment 130 of the first portion 123a and the first coil segment 130 of the second portion 123b are transposed relative to each other in the circumferential direction.

[0058] Next, the relationship between the second coil segments 130 will be described.

[0059] The first coil segment 130 of the first portion 123a has a straight portion 35u that is housed in the fifth layer of the 13th stator slot 111 and a straight portion 36u that is housed in the sixth layer of the 18th stator slot 111. The first coil segment 130 of the second portion 123b has a straight portion 35u that is housed in the fifth layer of the 12th stator slot 111 and a straight portion 36u that is housed in the sixth layer of the 19th stator slot 111.

[0060] As a result, on the axial outside of the first end 110a of the stator core 110, the first coil segment 130 of the first portion 123a is arranged along and inside the first coil segment 130 of the second portion 123b. That is, in the second coil segment 130, the first coil segment 130 of the first portion 123a and the first coil segment 130 of the second portion 123b are also transposed relative to each other in the circumferential direction. However, the relationship between the first portion 123a and the second portion 123b in the second coil segment 130 is the opposite of the relationship between the first portion 123a and the second portion 123b in the first coil segment 130.

[0061] As shown in this example, on the axial outside of the first end 110a of the stator core 110, the coil segments 130 of the first portion 123a and the coil segments 130 of the second portion 123b are transposed in the circumferential direction, alternating between them. This relationship is also true for the folded portion.

[0062] Comparative Example FIG. 6 is a connection diagram showing an example of the connection state between the straight portions of each layer in each stator slot 111 of a conventional stator winding as a comparison example.

[0063] First, the non-parallel section is made from the straight section 1u connected to the lead wire connection section 141 to the straight section 8u, going around the first and second layers, with a circumferential offset of 5 slots and a circumferential offset of 7 slots alternately repeated. That is, the arrangement is such that a circumferential offset of 1 pole minus 1 slot and a circumferential offset of 1 pole plus 1 slot are repeated.

[0064] After making one circuit between the first and second layers, the wire is similarly wound around the third and fourth layers from the straight portion 9u to the straight portion 16u as a non-parallel portion 122.

[0065] Next, the coil segments 130 are connected to the parallel portion 123. In the parallel portion 123, the coil segments 130 are arranged from the straight portion 17u to the straight portion 20u, then turn back to the straight portion 24u, and are connected to the straight portion 25u of the fourth layer, which is a non-parallel portion. As for the slot spacing, the coil segments 130 of the first portion and the coil segments 130 of the second portion are displaced relative to each other in the circumferential direction, as in the present embodiment.

[0066] The return non-parallel portion 122 makes one circumferential turn between the fourth and third layers from the straight portion 25u to the straight portion 32u, and then makes one circumferential turn between the second and first layers from the straight portion 33u to the straight portion 40u.

[0067] Next, the wires extend from the first layer 40u to the first layer 41u. Similarly, the wires extend from the first layer 41u to the first layer 80u connected to the neutral wire connection portion 142, from the outer side to the inner side in the radial direction, and then turn around and extend toward the outer side in the circumferential direction. That is, as follows.

[0068] The non-parallel section extends from the straight section 41u to the straight section 48u, spanning between the first and second layers, and goes around the circumference. The poles are alternately shifted by 7 slots and 5 slots. That is, the poles are arranged so that the poles are shifted by 1 pole plus 1 slot and minus 1 slot in the circumferential direction.

[0069] After making one circuit between the first and second layers, the wire is wound around the third and fourth layers in the same manner from the straight portion 49u to the straight portion 56u as a non-parallel portion 122.

[0070] Next, the coil segments 130 are connected to the parallel portion 123. In the parallel portion 123, the coil segments 130 are arranged from the straight portion 57u to the straight portion 60u, then turn back to the straight portion 64u, and are connected to the straight portion 65u of the fourth layer, which is the non-parallel portion 122. As for the slot spacing, the coil segments 130 of the first portion and the coil segments 130 of the second portion are displaced relative to each other in the circumferential direction, as in the present embodiment.

[0071] The return non-parallel portion 122 makes one circumferential turn between the fourth and third layers from the straight portion 65u to the straight portion 72u, and then makes one circumferential turn between the second and first layers from the straight portion 73u to the straight portion 80u.

[0072] As described above, in the conventional example, the phase conductors 121 are arranged from the radially outer side toward the radially inner side, folded back at the innermost periphery, returned to the outermost periphery, and then arranged again in the same manner. As a result, there are four folds in the parallel portion 123 and one fold in the non-parallel portion 122.

[0073] <Actions and Effects of the Present Embodiment> In the present embodiment, the two inner layers are parallel to each other and are transposed relative to each other in the circumferential direction, thereby making it possible to reduce AC copper loss, which becomes a problem particularly on the inner side as the frequency increases.

[0074] Furthermore, in this embodiment, by winding the non-parallel portion 122 twice between each two layers, it is possible to simplify the wiring and improve workability while ensuring the same number of windings as in the conventional case.

[0075] That is, in this embodiment, the phase conductor 121 is wound two times between the first and second layers and between the third and fourth layers in the forward and return paths. As a result, the non-parallel portion 122 and the parallel portion 123 are connected only once in each of the forward and return paths. As a result, the conductor is folded back only at the innermost portion of the parallel portion 123. In other words, there are only two folds. Specifically, the number of folds is reduced to two from five in the conventional example. Furthermore, the number of folds at the outermost periphery, which has a particularly large impact on the layout, can be reduced.

[0076] In this way, as shown in the example of the number of folding points, the wiring is simplified. Furthermore, since the number of transitions to different phases is reduced, the number of times that the position of the stator core 110 on the work stand and the number of times that the worker needs to change the access direction to the stator core 110 are also reduced. As a result, the burden on the manufacturing work can be reduced and the work time can be shortened.

[0077] Second Embodiment FIG. 7 is a partial cross-sectional view of a rotor and a stator showing a state in which a stator winding 120a is housed in a stator 100 according to a second embodiment.

[0078] This embodiment is a modification of the first embodiment. The range of the parallel portion 123 extends to the third layer conductor 131c, the fourth layer conductor 131d, the fifth layer conductor 131e, and the sixth layer conductor 131f. The radial thickness of the first layer conductor 131a and the second layer conductor 131b is t0, and the thickness t1 of the range of the parallel portion 123 is half of t0.

[0079] Fig. 8 is a connection diagram showing the connection state between the straight portions 131 of each layer in each stator slot 111 of the stator winding 120a of the stator 100 according to the second embodiment. Also, Fig. 9 is a connection diagram showing the connection state between the straight portions 131 of each layer in each stator slot 111 of the stator winding 120a of the stator 100 according to the second embodiment.

[0080] The first and second layers of the non-parallel portion 122 are arranged in the same manner as in the first embodiment.

[0081] The arrangement of the third and fourth layers and the arrangement of the fifth and sixth layers, which are the parallel portion 123, are similar to the arrangement of the fifth and sixth layers in the first embodiment.

[0082] <Operations and Effects> In the second embodiment, the two inner layers are parallel sections, which makes it possible to reduce AC copper loss, which becomes a problem particularly on the inner side as the frequency increases.

[0083] In the future, if the frequency of the rotating electrical machine 1 continues to increase, it is expected that AC copper loss will become a problem not only at the innermost periphery but also on the outer radial side thereof.

[0084] In addition to the same effects as those of the first embodiment, this embodiment can reduce AC copper loss even when the frequency increases as described above.

[0085] [Third embodiment] Fig. 10 is a connection diagram showing the connection state between the straight portions 131 of each layer in each stator slot 111 of the stator winding 120b of the stator 100 according to the third embodiment. Fig. 11 is a connection diagram showing the connection state between the straight portions 131 of each layer in each stator slot 111 of the stator winding 120b of the stator 100 according to the third embodiment.

[0086] This embodiment is a modification of the first embodiment. While the phase conductors 121 in the stator winding 120 of the first embodiment are formed in a single row, the phase conductors 121b in the stator winding 120b of this embodiment have a first series phase conductor 135a and a second series phase conductor 135b arranged in parallel with each other.

[0087] <First series phase conductor 135a> The first series phase conductor 135a is similar to the outgoing part in Embodiment 1. Here, the outgoing part in the first embodiment includes the part from the straight part 1u connected to the lead wire connection part 141 to the straight part 32u, which is the outgoing part of the non-parallel part 122, and the part from the straight part 33u to the straight part 40u of the first part 123a and the second part 123c, which is the outgoing part of the parallel part 123.

[0088] In the first embodiment, the straight line portion 40u is folded back to the straight line portion 41u and connected to the return path portion. On the other hand, in the present embodiment, the straight line portion 40u of each of the first portion 123a and the second portion 123c is connected to the neutral line connection portion 142.

[0089] <Second-series phase conductor 135b> In the second-series phase conductor 135b, the straight portion 131 is arranged in the same manner as the return path portion in the first embodiment. The straight portion 1u of each of the first portion 123b and the second portion 123d is connected to the neutral line connection portion 142. However, instead of functioning as a return path, it functions as a circuit in parallel with the first-series phase conductor 135a.

[0090] Moreover, the straight line portions 131 corresponding to the two straight line portions 40u of the parallel circuit in the first embodiment are the two straight line portions 1u connected to the neutral wire connection portion 142. Moreover, the straight line portion 131 corresponding to the straight line portion 1u connected to the lead wire connection portion 141 in the first embodiment is the straight line portion 40u connected to the lead wire connection portion 141. In this way, the second series phase conductor 135b is configured such that the two straight line portions 1u connected to the neutral wire connection portion 142 to the straight line portion 40u connected to the lead wire connection portion 141 are connected.

[0091] <Functions and Effects> In this embodiment, the phase conductors 121 are broadly divided into first-series phase conductors 135a and second-series phase conductors 135b. As a result, each of the first-series phase conductors 135a and second-series phase conductors 135b is arranged in only one direction from the connection portion with the lead wire connection portion 141 to the neutral wire connection portion 142, and does not have any folded-back portions. As a result, the arrangement of the phase conductors 121 is simplified, and workability is improved.

[0092] [Fourth embodiment] Fig. 12 is a connection diagram showing the connection state between the straight portions 131 of each layer in each stator slot 111 of the stator winding 120c of the stator 100 according to the fourth embodiment. Fig. 13 is a connection diagram showing the connection state between the straight portions 131 of each layer in each stator slot 111 of the stator winding 120c of the stator 100 according to the fourth embodiment.

[0093] This embodiment is a modification of the first embodiment, and combines the features of the second embodiment and the third embodiment. That is, the phase conductor 121c of the stator winding 120c has both the feature of the third embodiment in that the phase conductor 121b has a first-series phase conductor 135a and a second-series phase conductor 135b, and the feature of the second embodiment in that the area of ​​the parallel portion 123 is expanded.

[0094] The configuration has been explained in the second and third embodiments, so the explanation will be omitted in this embodiment.

[0095] With this configuration of the present embodiment, it is possible to have the features of both the second and third embodiments.

[0096] According to the embodiments described above, it is possible to provide a stator and a rotating electric machine in which the complexity of the stator winding having transposed parallel portions is reduced.

[0097] [Other Embodiments] Although the embodiments of the present invention have been described above, they are presented as examples and are not intended to limit the scope of the invention. Furthermore, features of each embodiment may be combined. Furthermore, the embodiments may be implemented in various other forms, and various omissions, substitutions, and modifications may be made without departing from the spirit of the invention. The embodiments and their modifications are intended to be included within the scope and spirit of the invention, as well as within the scope of the invention and its equivalents as set forth in the claims.

[0098] 1... rotating electric 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, 112... stator teeth, 120, 120a, 120b, 120c... stator winding, 12 1, 121b, 121c...phase conductor, 122...non-parallel portion, 123...parallel portion, 123a, 123c...first portion, 123b, 123d...second portion, 128...segment connection portion, 130...coil segment, 131...straight portion, 132...bridge portion, 135a...first series phase conductor, 135b...second series phase conductor, 141...lead wire connection portion, 142...neutral wire connection portion

Claims

1. A stator comprising: a cylindrical stator core having a plurality of axially extending stator slots formed on its inner peripheral surface at intervals in the circumferential direction; and a stator winding comprising, for each phase, a plurality of coil segments using flat rectangular conductors, each having a straight portion accommodated in two mutually different stator slots and a bridging portion connecting the two straight portions outside a first axial end of the stator core; and a phase conductor comprising a plurality of segment connection portions connecting the plurality of coil segments in series outside a second axial end of the stator core, the phase conductor extending from a lead wire connection portion connecting to an external lead wire to a neutral wire connection portion connecting to a neutral point, wherein the straight portions form N layers (N is an even number of 4 or more) from the radial outside in each of the plurality of stator slots, from the first layer to the Nth layer; and the phase conductor has a parallel portion in which first and second portions arranged in two layers, the Nth layer and the (N-1)th layer on the inner peripheral side, are connected in parallel to each other, a stator characterized in that non-parallel portions of the phase conductors excluding the parallel portions are laid M times (M is an integer of 2 or more) around the entire circumference in two layers from the outside in the radial direction, and the parallel portions are laid fewer than M times around the entire circumference in the circumferential direction.

2. A stator as described in claim 1, characterized in that the straight portions of the coil segments of the first portion are offset from each other at least once by one pole plus one slot or by the one pole minus the one slot, and the second portion is located at a position offset from the first portion by the one slot, and the straight portions of the coil segments are offset from each other at least once by one pole minus the one slot or by the one pole plus the one slot.

3. The stator according to claim 1, wherein the parallel portion is also formed in two layers, the (N-3)th layer and the (N-4)th layer.

4. A stator as described in claim 1, characterized in that the phase conductors consist of a first series phase conductor and a second series phase conductor arranged in parallel, the first series phase conductor has the lead wire connection portion arranged in the outermost layer and the neutral wire connection portion arranged in the innermost layer, and the second series phase conductor has the lead wire connection portion arranged in the innermost layer and the neutral wire connection portion arranged in the outermost layer.

5. A stator according to claim 1, characterized in that the radial thickness of the rectangular conductors in the parallel section is substantially half the radial thickness of the rectangular conductors in the non-parallel section.

6. A rotating electric machine comprising: a rotor having a rotor shaft extending in the axial direction and a rotor core attached to the rotor shaft and accommodating a permanent magnet; and a stator according to any one of claims 1 to 5.

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