Stator and rotary electric machine

Abstract

To make it possible to secure a cross-sectional area of a rectangular conductor and suppress an increase in copper loss.SOLUTION: According to an embodiment, a stator 100 includes a stator winding 120 including a stator core, a coil segment 130 having two straight portions 131 and a bridging portion 132, and a segment connecting portion 128 connecting them, and a phase conductor 121 extending from a lead wire connecting portion 141 to a neutral dotted line connecting portion 142. The phase conductor 121 repeats an inner direction wiring 121a laid from a first layer to a Nth layer without connection between the same layers, an innermost layer circumferential direction wiring 121f laid in a circumferential direction in the Nth layer, an outer direction wiring 121b extending from the Nth layer without connection between the same layers and laid to the first layer, and an outermost layer circumferential direction wiring 121g laid in the circumferential direction in the first layer. The second innermost layer circumferential direction wiring 121f is laid to a position shifted by a predetermined number of slots in the Nth layer.SELECTED DRAWING: Figure 4

Description

[Technical Field]

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

[0002] In electric motors and generators used in EVs (electric vehicles) and PEVs (plug-in electric vehicles), large currents flow through the stator windings, so rectangular wires with large cross-sectional areas are used as the conductors for the stator windings.

[0003] Furthermore, from the viewpoint of facilitating control of the rotation speed in a desired pattern, a method of driving the electric motor by an inverter is often adopted. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-152006 Summary of the Invention [Problem to be solved by the invention]

[0005] In recent years, the adoption of inverter drive systems has led to a trend toward higher voltages in the drive power of rotating electrical machines. This increases the potential difference between the rectangular conductors (layers) stacked in the stator slots. Furthermore, the high-frequency components in the drive power are not distributed evenly across the stator windings, and tend to be biased toward the surface of the stator. This tends to increase the voltage distribution, especially in the areas closer to the connections with the external lead wires.

[0006] In this way, the potential difference between the layers of the rectangular conductors stacked in the stator slot increases. As a result, the required thickness of the insulation between the layers increases. Expanding the space of the stator slot to accommodate the increased thickness of the insulation would narrow the magnetic path in the stator core, making it difficult. Therefore, to accommodate the increased thickness of the insulation, the cross-sectional area of ​​the rectangular conductor must be reduced, resulting in increased copper loss and reduced efficiency of the rotating electric machine.

[0007] An object of the embodiments of the present invention is to provide a stator and a rotating electric machine that can ensure the cross-sectional area of ​​a rectangular conductor and suppress an increase in copper loss. [Means for solving the problem]

[0008] In order to achieve the above-mentioned object, the stator according to this embodiment is 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; 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 axial end of the stator core; and a stator winding provided with phase conductors for each phase, each 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 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, The plurality of straight portions form N layers (N is an even number equal to or greater than 3) in the radial direction in each of the plurality of stator slots, and the phase conductors are arranged in a repeated pattern of inward directional wiring extending from a first layer, which is the outermost layer in the radial direction, toward the inside in the radial direction without connection between layers, and laid to an Nth layer, which is the innermost layer in the radial direction, an innermost layer circumferential wiring laid in the circumferential direction in the Nth layer, an outward directional wiring extending from the Nth layer toward the outside in the radial direction without connection between layers, and laid to the first layer, and an outermost layer circumferential wiring laid in the circumferential direction in the first layer, and the second time the innermost layer circumferential wiring is laid in the Nth layer to a position shifted by a predetermined number of slots. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a vertical cross-sectional view showing an example of the configuration of a rotating electric machine according to a first embodiment. [Figure 2] 1 is a cross-sectional view of a rotor and a stator showing an example of the configuration of a rotating electric machine according to a first embodiment. [Figure 3] 2 is a partial cross-sectional view of a rotor and a stator showing a state in which a stator winding is housed in the stator according to the first embodiment. FIG. [Figure 4] FIG. 2 is a connection diagram showing a connection state between straight portions of each layer in each stator slot of the stator winding of the stator according to the first embodiment. [Figure 5] FIG. 10 is a connection diagram showing an example of a connection state between straight portions of each layer in each stator slot of a conventional stator winding for comparison. [Figure 6] FIG. 10 is a connection diagram showing a connection state between straight portions of each layer in each stator slot of a stator winding of a stator according to a second embodiment. [Figure 7] FIG. 10 is a connection diagram showing a connection state between straight portions of each layer in each stator slot of a stator winding of a stator according to a third embodiment. [Figure 8] FIG. 10 is a connection diagram showing a connection state between straight portions of each layer in each stator slot of a stator winding of a stator according to a fourth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] 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.

[0011] [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.

[0012] The rotating electric machine 1 includes a rotor 10, a stator 100, a bearing 21, a bearing bracket 22, and a frame 23.

[0013] 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 to the radial outside of the rotor shaft 11, and a permanent magnet 13 arranged in the rotor core 12. Note that while Fig. 1 illustrates a permanent magnet type synchronous machine as the rotor 10, it may be a wound type or an induction type rotor.

[0014] Hereinafter, the radial direction is the direction radially away from the rotation axis CL in a cross section perpendicular to the rotation axis CL, and the circumferential direction is the direction in which any part in the rotating body moves.

[0015] The stator 100 has a stator core 110 provided radially outside the rotor core 12 , and a stator winding 120 wound around the stator core 110 .

[0016] The stator winding 120 is a winding using a rectangular conductor insulated with, for example, enamel. The stator winding 120 forms a multi-phase, for example, three-phase, circuit. Each phase of the stator winding 120 has a phase conductor 121 extending from a lead wire connection portion 141 (FIG. 4) that connects to an external lead wire to a neutral wire connection portion 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.

[0017] 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 inside 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 portion 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 portion 110b of the stator core 110.

[0018] The two straight portions 131 are connected to other coil segments 130 at the outside of the second end 110b by segment connection portions 128. Here, the segment connection portions 128 are, for example, welded or brazed portions. Note that the straight portion 131 at the outside of the second end 110b has a shape that follows the circumferential direction and is not linear, but in the following description, for convenience, this portion will not be distinguished and will be referred to as the straight portion 131.

[0019] 2 is a cross-sectional view of a rotor 10 and a stator 100 showing an example of the configuration of a rotating electric machine 1 according to the first embodiment. A surrounded by a dashed line will be described later with reference to FIG.

[0020] 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.

[0021] 2 has two permanent magnets 13 housed at each magnetic pole in 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.

[0022] 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 details of part A of the rotating electric machine 1 shown in FIG.

[0023] A plurality of stator slots 111, which are through grooves extending in the axial direction and spaced apart from one another in the circumferential direction, are formed on the radially 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.

[0024] In each stator slot 111, a plurality of flat conductors with rectangular cross sections, which are straight portions 131 of coil segments 130, are stacked radially while being electrically insulated from one another. When the coil segments 130 and the segment connection portions 128 (FIG. 1) form the phase conductors 121 (FIG. 1) of the stator winding 120, the number N of laminations of the straight portions 131 stacked in each stator slot 111 is an even number of 2 or more.

[0025] 3, each stator slot 111 is provided with a first layer conductor 131a, a second layer conductor 131b, a third layer conductor 131c, a fourth layer conductor 131d, a fifth layer conductor 131e, and a sixth layer conductor 131f arranged in this order from the outside to the inside in the radial direction. That is, in this case, the number of laminations N is 6. The straight portion 131 is a general term for these.

[0026] Hereinafter, these rectangular conductors that are straight portions 131 will be referred to as n-th layer conductors (n=1 to N) according to the order of the layers, regardless of the stator slots 111. Alternatively, they will be referred to as n-th layer straight portion 131 or n-th layer straight portion 131.

[0027] FIG. 4 is a connection diagram showing the connection state between the straight portions 131 of the respective layers in each stator slot 111 of the stator winding 120 of the stator 100 according to the first embodiment.

[0028] Here, Figure 4 explains an example of a three-phase, eight-pole rotor with two slots per pole per phase, for a total of 48. Therefore, in the case of full-pitch winding, one pole is six slots. Also, a shift of one pole means a shift of six slots.

[0029] 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.

[0030] In FIG. 4, dashed lines indicate bridge portions 132 of coil segments 130. Alternatively, dashed lines may indicate portions of coil segments 130 that include part of straight portions 131 and are located outside the first end 110a of the stator 100. The reference numerals written on the cells on both ends of the dashed lines of the bridge portions 132 indicate the straight portions 131 housed in that layer of the stator slot 111. Furthermore, solid lines indicate portions located outside the second end 110b of the stator 100, including the segment connection portion 128. In the phase conductor 121, the coil segments 130 are connected in series from the lead wire connection portion 141 to the neutral wire connection portion 142. The straight portions 131 along this line are indicated by consistent numbers from straight portion 1u to straight portion 96u.

[0031] The phase conductor 121 in this embodiment has an inside directional wire 121a, an outside directional wire 121b, an innermost layer circumferential wire 121f, and an outermost layer circumferential wire 121g, which will be described below.

[0032] The inner directional wiring 121a extends from the first layer, which is the outermost layer in the radial direction, toward the inside in the radial direction without connection between layers, and is laid down to the Nth layer, which is the innermost layer in the radial direction. The inner directional wiring 121a extends from the first layer to the Nth layer, passing through stator slots 111 that are shifted by one pole. Here, the direction of the shift by one pole is the same in each layer. That is, the direction is the direction in which the slot number increases by six slots, or conversely, the direction in which the slot number decreases by six slots.

[0033] The outer directional wiring 121b extends radially outward from the Nth layer to the first layer without connection between layers. The outer directional wiring 121b extends from the Nth layer to the first layer, passing through stator slots 111 that are shifted by one pole. The direction of the shift by one pole is the same in each layer. The direction is opposite to the shift direction of the inner directional wiring 121a. That is, the direction is one in which the slot number decreases by six slots, or conversely, one in which the slot number increases by six slots.

[0034] The innermost circumferential wiring 121f is laid in the circumferential direction in the Nth layer so as to connect the Nth layer of the inside directional wiring 121a and the Nth layer of the outside directional wiring 121b. As a result, the phase conductor 121 changes direction from the inside directional wiring 121a directed radially inward to the outside directional wiring 121b directed radially outward.

[0035] The outermost layer circumferential wiring 121g is laid in the circumferential direction in the first layer so as to connect the first layer of the outer directional wiring 121b and the first layer of the inner directional wiring 121a. As a result, the phase conductor 121 changes direction from the outer directional wiring 121b extending radially outward to the inner directional wiring 121a extending radially inward.

[0036] The wiring of the phase conductor 121 repeats, between the lead wire connection portion 141 and the neutral wire connection portion 142, an inside directional wiring 121a, an innermost layer circumferential wiring 121f, an outside directional wiring 121b, and an outermost layer circumferential wiring 121g.

[0037] Furthermore, a feature of this embodiment is that the second innermost circumferential wiring 121f, which connects the second inner directional wiring 121a and the second outer directional wiring 121b, is offset by a predetermined number of slots. Here, the predetermined number of slots is either the number of slots for an odd number of poles, the number of slots for the odd number of poles minus one slot, or the number of slots for the odd number of poles plus one slot. Here, the odd number of poles is used because if an even number of poles were used, the direction of the current would be reversed, preventing the formation of a coil, i.e., reducing the magnetic force.

[0038] Specific details of the layout of the phase conductor 121 will be described below with reference to FIG.

[0039] First, the lead wire connection portion 141 is connected to the straight portion 1u housed in the first layer of the 48th stator slot 111.

[0040] The first inward directional wiring 121a is laid extending from the straight portion 1u to the straight portion 6u. Specifically, the straight portion 1u is connected in the first layer of the 48th stator slot 111, the straight portion 2u is connected in the second layer of the 6th stator slot 111, the straight portion 2u is connected in the second layer of the 6th stator slot 111, the straight portion 3u is connected in the third layer of the 12th stator slot 111, the straight portion 4u is connected in the fourth layer of the 18th stator slot 111, the straight portion 5u is connected in the fifth layer of the 24th stator slot 111, and the straight portion 6u is connected in the sixth layer of the 30th stator slot 111.

[0041] In this way, the stator slots 111 are laid so that the circumferential positions of the slots 111 shift by one pole in the direction in which the slot numbers increase as one moves toward the innermost layer. Hereinafter, the direction in which the stator slot 111 numbers increase circumferentially will be referred to as the positive circumferential direction, and the direction in which the stator slot 111 numbers decrease circumferentially will be referred to as the negative circumferential direction.

[0042] The first innermost circumferential wiring 121f extends from the straight portion 6u housed in the sixth layer of the 30th stator slot 111 to the straight portion 7u housed in the sixth layer of the 24th stator slot 111. In other words, it extends in the negative circumferential direction, which is opposite to the circumferential direction of the inward circumferential wiring 121a that extends in the positive circumferential direction.

[0043] The first outer directional wiring 121b is laid extending from the straight portion 7u to the straight portion 12u. More specifically, the straight portion 7u is connected in the sixth layer of the 24th stator slot 111, the straight portion 8u is connected in the fifth layer of the 18th stator slot 111, the straight portion 9u is connected in the fourth layer of the 12th stator slot 111, the straight portion 10u is connected in the third layer of the 6th stator slot 111, the straight portion 11u is connected in the second layer of the 48th stator slot 111, and the straight portion 12u is connected in the first layer of the 42nd stator slot 111. In this way, the circumferential positions of the stator slots 111 are shifted by one pole as they move toward the outer layers, i.e., in the negative circumferential direction.

[0044] The first outermost circumferential wiring 121g extends from the straight portion 12u housed in the first layer of the 42nd stator slot 111 to the straight portion 13u housed in the first layer of the 36th stator slot 111. In other words, it extends in the same circumferential direction as the outer circumferential wiring 121b.

[0045] This cycle is repeated until the wire finally extends to the straight portion 96u housed in the first layer of the 19th stator slot 111, and is then connected to the neutral wire connection portion 142. As a result, two parallel-arranged inner directional wirings 121a and two parallel-arranged outer directional wirings 121b are alternately arranged in the circumferential direction.

[0046] The deviation widths of the innermost layer circumferential wiring 121f and the outermost layer circumferential wiring 121g are as follows:

[0047] The innermost circumferential wiring 121f has a deviation of six slots in the negative circumferential direction the first time, a predetermined deviation in the positive circumferential direction the second time, and a deviation of six slots in the positive circumferential direction from the third to eighth times.

[0048] Here, the predetermined shift width in the positive circumferential direction for the second time is either the number of slots for the odd number of poles, the number of slots one slot less than the number of odd poles, or the number of slots one slot more than the number of odd poles. Also, the number of odd poles is three or more. 4, the second innermost circumferential wiring 121f is a portion extending from the straight portion 18u to the straight portion 19u. In the case shown in Fig. 4, the straight portion 18u is housed in the 6th layer of the 18th stator slot 111, and the straight portion 19u is housed in the 6th layer of the 36th stator slot 111. In other words, the straight portion 19u is offset from the straight portion 18u by 18 slots, or three poles, in the direction in which the slot number increases.

[0049] The outermost layer circumferential wiring 121g has a deviation of 6 slots in the negative circumferential direction for the first time, a predetermined deviation in the positive circumferential direction for the second and third times, a deviation of 5 slots in the negative circumferential direction for the fourth time, and a deviation of 6 slots in the positive circumferential direction for the fifth to seventh times.

[0050] <Transformation> In the embodiment described above, the dashed lines indicate the bridge portions 132 of the coil segments 130, and the solid lines indicate the outer portions of the second end 110b of the stator 100, including the segment connection portions 128. Alternatively, the solid lines may indicate the bridge portions 132 of the coil segments 130, and the dashed lines may indicate the outer portions of the second end 110b of the stator 100, including the segment connection portions 128. Also, in the embodiment, the straight portion 1u is connected to the lead wire connection portion 141, and the straight portion 96u is connected to the neutral wire connection portion 142. Alternatively, the straight portion 96u may be connected to the lead wire connection portion 141, and the straight portion 1u may be connected to the neutral wire connection portion 142, in the opposite direction. This also applies to the following embodiments.

[0051] <Comparative Example> FIG. 5 is a connection diagram showing an example of the connection state between the straight portions of each layer in each slot of a conventional stator winding for comparison.

[0052] 5 is similar to the present embodiment in that an inside directional wiring 121a, an innermost layer circumferential wiring 121f, an outside directional wiring 121b, and an outermost layer circumferential wiring 121g are repeated between a lead wire connection portion 141 and a neutral dot wire connection portion 142. The inside directional wiring 121a and the outside directional wiring 121b are also similar to the present embodiment.

[0053] On the other hand, the innermost layer circumferential wirings 121f are all offset by six slots in the negative circumferential direction, i.e., one pole. Also, the outermost layer circumferential wirings 121g are all offset by six slots in the positive circumferential direction, i.e., one pole. Thus, the comparative example is a case of wiring using a simple method.

[0054] <Comparison of Effects Between This Embodiment and Comparative Example> Because the voltage share in the portion closer to the lead wire connection portion 141 is large, the potential difference between adjacent straight portions 111 in the same stator slot 111 becomes particularly problematic in the portion closer to the lead wire connection portion 141. Below, we will look at the straight portion 131 closer to the lead wire connection portion 141, which is particularly problematic.

[0055] In the case of the straight portion 131 close to the lead wire connection portion 141 in the comparative example, the straight portion 1u is adjacent to the straight portion 11u, the straight portion 2u is adjacent to the straight portion 48u, the straight portion 3u is adjacent to the straight portion 47u, the straight portion 4u is adjacent to the straight portion 46u, and the straight portion 5u is adjacent to the straight portion 45u.

[0056] On the other hand, in the case of the straight line portion 131 close to the lead wire connection portion 141 in this embodiment, the following applies: the straight line portion 1u is adjacent to the straight line portion 11u, the straight line portion 2u is adjacent to the straight line portion 24u, the straight line portion 3u is adjacent to the straight line portion 23u, the straight line portion 4u is adjacent to the straight line portion 22u, and the straight line portion 5u is adjacent to the straight line portion 21u.

[0057] As described above, in this embodiment, compared to the comparative example, the outer directional wiring 121b adjacent to the first inner directional wiring 121a has a straight portion 131 that is closer to the lead wire connection portion 141. As a result, in this embodiment, the potential difference between adjacent straight portions 131 in the same stator slot 111 is smaller than in the comparative example.

[0058] Here, we will show an example of a method for semi-quantitatively confirming the effect. As indicators of the effect of reducing the potential difference between layers of rectangular conductors stacked in a stator slot, the interlayer index Δm and the interlayer index ratio r are defined as follows:

[0059] First, let the total number of straight portions 131 be M. In this embodiment, M is 96. Let m (m = 1 to M) be the number of the straight portions 131. For example, if the straight portion 131 is 9u, m is 9. For each m-th straight portion 131 in the range of 1 to M0, the absolute value of the difference between the number m1 of the adjacent straight portion 131 in the same stator slot 111 is taken as the interlayer index Δm (> 0). Here, if there are two adjacent straight portions 131, the one with the larger interlayer index Δm is selected. This total value within the range of Δm (m = 1 to M / 4) is taken as the interlayer index Z. Let the ratio of the interlayer index Δm in this embodiment to the interlayer index Δm in the comparative example be taken as the interlayer index ratio r.

[0060] For example, the interlayer index Δm in the range until the second inner directional wiring 121a is completed, i.e., when M0 is 18, is 308 in the comparative example and 293 in the present embodiment. The interlayer index Δm ratio r at this time is 0.95. The interlayer index Δm in the range until the first outer directional wiring 121b is completed, i.e., when M0 is 12, is 260 in the comparative example and 133 in the present embodiment. The interlayer index ratio r at this time is 0.51. Furthermore, the interlayer index Δm in the range until the first inner directional wiring 121a is completed, i.e., when M0 is 6, is 220 in the comparative example and 100 in the present embodiment. The interlayer index ratio r at this time is 0.45.

[0061] In this way, the effect of this embodiment becomes greater in a portion closer to the lead wire connection portion 141 where the voltage share increases and the interlayer potential difference widens.

[0062] As described above, in this embodiment, the offset widths of the innermost layer circumferential wiring 121f and the outermost layer circumferential wiring 121g are set so that the interlayer index Δm becomes small when the inward directional wiring 121a and the outward directional wiring 121b, which extend in one of the circumferential and radial directions, are adjacent to each other. Here, the second innermost layer circumferential wiring 121f is offset by a predetermined number of slots, i.e., three poles, so that the interlayer index Δm does not increase.

[0063] This configuration prevents an increase in the potential difference between the rectangular conductors stacked in the stator slot 111, and also prevents an increase in the required thickness of the insulating portion between the layers. As a result, the cross-sectional area of ​​the rectangular conductors can be secured, and an increase in copper loss can be prevented.

[0064] [Second embodiment] FIG. 6 is a connection diagram showing the connection state between the straight portions 131 of the respective layers in each stator slot 111 of the stator winding 120a of the stator 100 according to the second embodiment.

[0065] This embodiment is a modification of the first embodiment.

[0066] The phase conductor 121 in this embodiment has an inside directional wire 121c, an outside directional wire 121d, an innermost layer circumferential wire 121f, and an outermost layer circumferential wire 121g, which will be described below.

[0067] The inward direction wiring 121c extends radially inward in the positive circumferential direction on the bridge portion 132 side of the coil segment 130 shown by the dashed line, and in the negative circumferential direction on the segment connection portion 128 side shown by the solid line.

[0068] Similarly, the outermost layer circumferential wiring 121g extends radially outward in the negative circumferential direction on the side of the bridge portion 132 of the coil segment 130 shown by the dashed line, and in the positive circumferential direction on the side of the segment connection portion 128 shown by the solid line.

[0069] The innermost layer circumferential wiring 121f and the outermost layer circumferential wiring 121g are offset by a width such that the interlayer index Δm between the adjacent inner directional wiring 121a and outer directional wiring 121b is small. To prevent the interlayer index Δm from increasing, the second innermost layer circumferential wiring 121f is offset by a predetermined number of slots, i.e., three poles. As a result, two parallel-arranged inner directional wirings 121a and two parallel-arranged outer directional wirings 121b are alternately arranged in the circumferential direction.

[0070] In the present embodiment, the interlayer index Δm and the interlayer index ratio r are as follows:

[0071] For example, the interlayer index Δm in the range until the second inner directional wiring 121a is completed, i.e., when M0 is 18, is 308 in the comparative example and 225 in the present embodiment. The interlayer index Δm ratio r at this time is 0.73. The interlayer index Δm in the range until the first outer directional wiring 121b is completed, i.e., when M0 is 12, is 260 in the comparative example and 109 in the present embodiment. The interlayer index ratio r at this time is 0.42. Furthermore, the interlayer index Δm in the range until the first inner directional wiring 121a is completed, i.e., when M0 is 6, is 220 in the comparative example and 76 in the present embodiment. The interlayer index ratio r at this time is 0.35.

[0072] In this way, in the portion close to the lead wire connection portion 141 where the voltage share increases and the interlayer potential difference widens, the interlayer index ratio r further decreases compared to the first embodiment.

[0073] That is, when the high frequency component is large, the voltage share in the portion close to the lead wire connection portion 141 becomes large, and the interlayer potential difference tends to increase, this embodiment is more effective.

[0074] [Third embodiment] FIG. 7 is a connection diagram showing the connection state between the straight portions 131 of the respective layers in each stator slot 111 of the stator winding 120b of the stator 100 according to the third embodiment.

[0075] This embodiment is a modification of the first embodiment. The second innermost layer circumferential wiring is offset by a predetermined number of slots. Here, the predetermined number of slots is either the number of slots for an odd number of poles, the number of slots for an odd number of poles minus one slot, or the number of slots for an odd number of poles plus one slot.

[0076] In the first embodiment, the predetermined number of slots in the second innermost circumferential wire 121f is three poles, i.e., 18 slots. On the other hand, in the present embodiment, the predetermined number of slots in the second innermost circumferential wire 121f is one pole, i.e., 6 slots. Except for this, the present embodiment is the same as the first embodiment.

[0077] In the present embodiment, the interlayer index Δm and the interlayer index ratio r are as follows:

[0078] For example, the interlayer index Δm in the range until the second inner directional wiring 121a is completed, i.e., when M0 is 18, is 308 in the comparative example and 836 in the present embodiment. The interlayer index Δm ratio r at this time is 2.71. The interlayer index Δm in the range until the first outer directional wiring 121b is completed, i.e., when M0 is 12, is 260 in the comparative example and 432 in the present embodiment. The interlayer index ratio r at this time is 1.66. Furthermore, the interlayer index Δm in the range until the first inner directional wiring 121a is completed, i.e., when M0 is 6, is 220 in the comparative example and 100 in the present embodiment. The interlayer index ratio r at this time is 0.45.

[0079] That is, although the effect is smaller than that of the first embodiment, it can be used as an alternative method to the first embodiment when it is difficult to set the number of slots to three poles due to limitations on wiring routing, and when the high frequency components are particularly large.

[0080] [Fourth embodiment] FIG. 8 is a connection diagram showing the connection state between the straight portions 131 of the respective layers in each stator slot 111 of the stator winding 120c of the stator 100 according to the fourth embodiment.

[0081] This embodiment is a modification of the second embodiment. The second innermost layer circumferential wiring is offset by a predetermined number of slots. Here, the predetermined number of slots is either the number of slots for an odd number of poles, the number of slots for an odd number of poles minus one slot, or the number of slots for an odd number of poles plus one slot.

[0082] In the second embodiment, the predetermined number of slots in the second innermost circumferential wire 121f is three poles, i.e., 18 slots. On the other hand, in the present embodiment, the predetermined number of slots in the second innermost circumferential wire 121h is three poles, i.e., 18 slots. Except for this, the present embodiment is the same as the second embodiment.

[0083] In the present embodiment, the interlayer index Δm and the interlayer index ratio r are as follows:

[0084] For example, the interlayer index Δm in the range until the second inner directional wiring 121a is completed, i.e., when M0 is 18, is 308 in the comparative example and 580 in the present embodiment. The interlayer index Δm ratio r at this time is 1.88. The interlayer index Δm in the range until the first outer directional wiring 121b is completed, i.e., when M0 is 12, is 260 in the comparative example and 292 in the present embodiment. The interlayer index ratio r at this time is 1.12. Furthermore, the interlayer index Δm in the range until the first inner directional wiring 121a is completed, i.e., when M0 is 6, is 220 in the comparative example and 76 in the present embodiment. The interlayer index ratio r at this time is 0.35.

[0085] That is, although the effect is smaller than that of the second embodiment, it can be used as an alternative to the second embodiment when it is difficult to set the number of slots to three poles due to limitations on wiring routing, and when the high frequency components are particularly large.

[0086] According to the embodiments described above, it is possible to provide a stator and a rotating electric machine that can ensure the cross-sectional area of ​​the rectangular conductor and suppress an increase in copper loss.

[0087] [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. [Explanation of symbols]

[0088] DESCRIPTION OF SYMBOLS 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... stator winding, 121... phase conductor, 121a, 121c... inward directional wiring, 121b, 121d... outward directional wiring, 121f... innermost layer circumferential wiring, 121g... outermost layer circumferential wiring, 128... segment connection portion, 130... coil segment, 131... straight portion, 132... bridge portion, 141... lead wire connection portion, 142... neutral wire connection portion

Claims

1. a cylindrical stator core having a plurality of axially extending stator slots formed on its inner circumferential surface at intervals in the circumferential direction; a stator winding including, for each phase, a plurality of coil segments each using a rectangular conductor, each having a straight portion accommodated in each of the two different stator slots and a bridging portion connecting the two straight portions outside the first axial end of the stator core, and a plurality of segment connection portions connecting the plurality of coil segments in series outside the second axial end of the stator core, 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; A stator comprising: the plurality of linear portions form N layers (N is an even number equal to or greater than 2) in the radial direction in each of the plurality of stator slots, The phase conductor is Inward direction wiring extending from a first layer, which is the outermost layer in the radial direction, toward the inside in the radial direction without connection between the same layers, and laid to an Nth layer, which is the innermost layer in the radial direction; an innermost layer circumferential wiring laid in the circumferential direction in the Nth layer; Outer directional wiring extending from the Nth layer toward the outside in the radial direction without connection between the same layers and laid down to the first layer; an outermost layer circumferential wiring laid in the circumferential direction in the first layer; Repeat The second innermost layer circumferential wiring is laid to a position shifted by a predetermined number of slots in the Nth layer. A stator characterized by:

2. 2. The stator according to claim 1, wherein the predetermined number of slots is one of the number of slots for an odd number of poles, the number of slots one slot less than the number of odd poles, and the number of slots one slot more than the number of odd poles.

3. a cylindrical stator core having a plurality of axially extending stator slots formed on its inner circumferential surface at intervals in the circumferential direction; a stator winding including, for each phase, a plurality of coil segments each using a rectangular conductor, each having a straight portion accommodated in each of the two different stator slots and a bridging portion connecting the two straight portions outside the first axial end of the stator core, and a plurality of segment connection portions connecting the plurality of coil segments in series outside the second axial end of the stator core, 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; A stator comprising: the plurality of linear portions form N layers (N is an even number equal to or greater than 4) in the radial direction in each of the plurality of stator slots, The phase conductor is Inward direction wiring extending from a first layer, which is the outermost layer in the radial direction, toward the inside in the radial direction without connection between the same layers, and laid to an Nth layer, which is the innermost layer in the radial direction; an innermost layer circumferential wiring laid in the circumferential direction in the Nth layer; Outer directional wiring extending from the Nth layer toward the outside in the radial direction without connection between the same layers and laid down to the first layer; an outermost layer circumferential wiring laid in the circumferential direction in the first layer; Repeat the first outermost layer circumferential wiring is laid to a position shifted by a predetermined number of slots in the first layer; A stator characterized by:

4. 4. The stator according to claim 3, wherein the predetermined number of slots is either one of the number of slots for one pole less by one slot, and the number of slots for one pole more by one slot.

5. the inward directional wiring is arranged in the same direction as the extension from the first layer to the Nth layer in the circumferential direction, the outward directional wiring is arranged in the same direction as the circumferential direction with respect to the extension from the Nth layer to the first layer; 5. The stator according to claim 1, wherein the stator is a stator having a first end and a second end.

6. the inward direction wiring is alternately arranged in the opposite direction to the extension from the first layer to the Nth layer in the circumferential direction, the outward direction wiring is alternately arranged in the opposite direction to the extension from the Nth layer to the first layer in the circumferential direction; 5. The stator according to claim 1, wherein the stator is a stator having a first end and a second end.

7. a rotor including a rotor shaft extending in the axial direction, a rotor core attached to the rotor shaft, and a plurality of permanent magnets housed in the rotor core; The stator according to claim 1 ; A rotating electric machine comprising:

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