Stator core, rotating electric machine, and drive device

Abstract

This invention provides a stator core, a rotary motor, and a drive device. The stator core is a stator core composed of multiple stacked steel plates, including: an annular core back centered on a central axis; and multiple pole teeth extending radially from the core back. The radially facing side of the core back is provided with multiple axially extending welded portions that fix the multiple steel plates together, and axially extending grooves. The multiple welded portions include a first welded portion, a second welded portion, and a third welded portion arranged sequentially in the circumferential direction. The angle formed by the central axis, the first welded portion, and the second welded portion is greater than the angle formed by the central axis, the second welded portion, and the third welded portion. The grooves are disposed between adjacent first and second welded portions in the circumferential direction.

Description

Technical Field

[0001] This invention relates to a stator core, a rotary electric motor, and a drive device. Background Technology

[0002] As a stator core of a rotating electric machine, a structure composed of multiple layers of electromagnetic steel plates is known. In this case, the stacked steel plates are fixed to each other by welding their peripheries. Patent Document 1 discloses a structure in which welded portions are arranged at equal intervals on the outer peripheral surface of the stator core.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent document 1: Japanese Patent Application Publication No. 2010-268603. Summary of the Invention

[0006] However, magnetic flux also flows through the back portion of the stator core. Therefore, when the stator core is fixed by welding, it will affect the magnetic circuit and may worsen torque fluctuations. Therefore, a structure that can reduce torque fluctuations while fixing the stator core (steel plate) is required.

[0007] In view of the above, one of the objects of the present invention is to provide a stator core, a rotary motor and a drive device that can reduce torque ripple.

[0008] One embodiment of the stator core of the present invention is a stator core comprising multiple stacked steel plates. The stator core includes: an annular core back centered on a central axis; and multiple pole teeth extending radially from the core back. The radially facing side of the core back is provided with: multiple weld portions extending axially and fixing the multiple steel plates together; and a groove extending axially. The multiple weld portions include a first weld portion, a second weld portion, and a third weld portion arranged sequentially in a circumferential direction. The angle formed by the central axis, the first weld portion, and the second weld portion is greater than the angle formed by the central axis, the second weld portion, and the third weld portion. The groove is disposed between adjacent first and second weld portions in the circumferential direction.

[0009] One embodiment of the rotary electric motor of the present invention includes: a stator having the aforementioned stator core; and a rotor capable of rotating relative to the stator.

[0010] One embodiment of the drive device of the present invention includes: the aforementioned rotary motor; and a transmission device connected to the rotor.

[0011] According to one aspect of the present invention, a stator core, a rotary motor, and a drive device that can reduce torque ripple can be provided. Attached Figure Description

[0012] Figure 1 This is a schematic diagram of a driving device according to one embodiment.

[0013] Figure 2 This is an exploded perspective view of the stator core of one embodiment.

[0014] Figure 3 This is a perspective view of the stator core of one embodiment.

[0015] Figure 4 This is a top view of the stator core according to one embodiment.

[0016] Figure 5 It is Figure 4 A portion of the enlarged top view is shown.

[0017] Figure 6 This is a partial enlarged view of the stator core of the modified example.

[0018] Figure 7 This is a magnified view of a portion of the stator core in a modified example.

[0019] Figure 8 This is a graph showing the simulation results of torque fluctuations in the above embodiments.

[0020] (Symbol Explanation)

[0021] 10 Rotary motor; 30 Rotor; 40 Stator; 42 Coil; 43 Coil wire; 43U, 43V, 43W coil wire; 70 Stator core; 71 Core back; 72 Pole teeth; 75 Positioning slot (slot); 76 Welding part; 76A First welding part; 76B Second welding part; 76C Third welding part; 79 Steel plate; 100 Drive unit; J Central axis; L Bisection line; S slot; S2 V phase slot (first slot); S3 W phase slot (second slot); SL ​​slot center line (center line); TL Pole tooth center line (center line) Detailed Implementation

[0022] Hereinafter, with reference to the accompanying drawings, embodiments of which the present invention is applied will be described in detail.

[0023] Furthermore, in the accompanying drawings used in the following description, sometimes the characteristic parts are shown enlarged for emphasis and convenience, and the dimensional ratios of the constituent elements may not be the same as the actual dimensions. Additionally, sometimes non-characteristic parts are omitted from the illustrations for the same purpose.

[0024] Figure 1 This is a schematic diagram of the drive device 100 in this embodiment.

[0025] The drive unit 100 is a drive device installed in a vehicle that rotates the axle 64. Vehicles equipped with the drive unit 100 are hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHVs), and electric vehicles (EVs), which are powered by an electric motor. Figure 1 As shown, the drive device 100 includes a rotary motor 10 and a transmission device 60.

[0026] The transmission device 60 is connected to the rotary motor 10 and transmits the rotation of the rotary motor 10, i.e., the rotation of the rotor 30 described later, to the axle 64 of the vehicle. The transmission device 60 in this embodiment has a gear housing 61, a reduction gear 62 connected to the rotary motor 10, and a differential gear 63 connected to the reduction gear 62.

[0027] The differential 63 has a gear ring 63a. The torque output from the rotary motor 10 is transmitted to the gear ring 63a via the reduction gear 62. The lower end of the gear ring 63a is immersed in oil O stored in the gear housing 61. The oil O is lifted up by the rotation of the gear ring 63a. The lifted oil O is supplied to the reduction gear 62 and the differential 63, for example, as lubricating oil.

[0028] The rotary motor 10 is the part that drives the drive unit 100. The rotary motor 10 functions as both a motor and a generator. The rotary motor 10 is driven by a supplied alternating current to rotate the wheels and drive the vehicle. In addition, the rotary motor 10 regenerates the rotation of the gears and generates electricity from the alternating current.

[0029] The rotary electric motor 10 includes a motor housing 20, a rotor 30 rotatable about a central axis J extending axially, a stator 40, and bearings 34 and 35. The rotor 30 rotates relative to the stator 40. The bearings 34 and 35 support the rotor 30 for rotation.

[0030] The rotor 30 has a shaft 31 and a rotor body 32. Although not shown in the figure, the rotor body 32 has a rotor core and a rotor magnet fixed to the rotor core. The torque of the rotor 30 is transmitted to the transmission device 60.

[0031] Shaft 31 is rotatable about its central axis J. Shaft 31 is supported for rotation by bearings 34 and 35. Thus, bearings 34 and 35 support the rotor 30 for rotation. Bearings 34 and 35 are, for example, ball bearings. One end of shaft 31 protrudes into the gear housing 61. A reduction gear 62 is connected to the left end of shaft 31.

[0032] The stator 40 is radially opposed to the rotor 30 with a gap. More specifically, the stator 40 is located radially outside the rotor 30. The stator 40 is fixed inside the motor housing 20. The stator 40 has a stator core 70 and coils 42.

[0033] The stator core 70 is annular, surrounding the central axis J of the rotary motor 10. The stator core 70 is located radially outside the rotor 30. The stator core 70 surrounds the rotor 30.

[0034] Figure 2 This is an exploded perspective view of the stator core 70 of this embodiment. Figure 3 This is a perspective view of the stator core 70 of this embodiment. Figure 4 This is a top view of the stator core 70 in this embodiment. Figure 5 It is shown in magnification Figure 4 A magnified top view of a portion of the image.

[0035] like Figure 3 As shown, the stator core 70 of this embodiment is constructed by stacking multiple steel plates 79 in the thickness direction. The multiple steel plates 79 have the same shape. The steel plates 79 are formed, for example, by punching a rolled sheet-like base material. Known non-directional electromagnetic steel plates can be used as the steel plates 79. Alternatively, directional electromagnetic steel plates can be used instead of non-directional electromagnetic steel plates as the steel plates 79. The steel plates 79 have an easy magnetization direction. The easy magnetization direction of the steel plates 79 coincides with the rolling direction. Directional electromagnetic steel plates have a high directional magnetization ease, while the directional magnetization ease of non-directional electromagnetic steel plates is below a threshold value.

[0036] The steel plate 79 has an annular portion 79p and a plurality of pole tooth element portions 79t extending radially inward from the annular portion 79p. By stacking the steel plates 79 along the thickness direction, the annular portions 79p and the pole tooth element portions 79t are made to have the same shape when viewed along the axial thickness direction. By stacking the steel plates 79 along the thickness direction, the stacked plurality of annular portions 79p form a core back 71, and the stacked plurality of pole tooth element portions 79t form pole teeth 72.

[0037] like Figure 4 As shown, the stator core 70 has a core back 71 and a plurality of pole teeth 72. The core back 71 is annular about a central axis J. More specifically, the core back 71 is cylindrical and extends axially about the central axis J. Furthermore, the pole teeth 72 extend radially inward from the inner circumferential surface of the core back 71. That is, the pole teeth 72 extend radially from the core back 71.

[0038] Multiple pole teeth 72 are arranged at equal intervals along the circumferential direction. In this embodiment, 48 pole teeth 72 are provided on the core back 71. Grooves S are provided between adjacent pole teeth 72 in the circumferential direction.

[0039] like Figure 5As shown, the coil 42 is mounted on the stator core 70 by passing the coil wire 43 through slot S. The coil wire 43 passing through slot S is classified into U-phase coil wire 43U, V-phase coil wire 43V, and W-phase coil wire 43W. The U-phase, V-phase, and W-phase coil wires 43U, 43V, and 43W are subjected to AC voltages that are 120° out of phase with each other. Here, the slot S through which the U-phase coil wire 43U passes is designated as U-phase slot S1, the slot S through which the V-phase coil wire 43V passes is designated as V-phase slot S2, and the slot S through which the W-phase coil wire 43W passes is designated as W-phase slot S3. In the stator core 70, the slots S through which the U-phase coil wire 43U passes, the slots S through which the V-phase coil wire 43V passes, and the slots S through which the W-phase coil wire 43W passes are arranged in pairs along the circumferential direction.

[0040] like Figure 4 As shown, the outer edge of the annular portion 79p of the steel plate 79 is provided with three first recesses 79a for welding, three second recesses 79b for welding, and one positioning recess 79c for positioning. The first recesses 79a, the second recesses 79b, and the positioning recess 79c are notches that open radially outward.

[0041] In this embodiment, the first recess 79a and the second recess 79b have the same shape. However, the first recess 79a and the second recess 79b may also have different shapes. The three first recesses 79a are arranged at equal intervals along the circumference. Similarly, the three second recesses 79b are arranged at equal intervals along the circumference. That is, the three first recesses 79a are arranged at 120° intervals, and the three second recesses 79b are arranged at 120° intervals. The first recesses 79a and the second recesses 79b are arranged alternately along the circumference. The second recesses 79b are configured to be slightly offset from the circumferential center of the circumferentially adjacent first recesses 79a.

[0042] A positioning recess 79c is disposed circumferentially between the first recess 79a and the second recess 79b. The positioning recess 79c is located at the circumferential center between the first recess 79a and the second recess 79b. In this embodiment, the positioning recess 79c has a different shape than the first recess 79a and the second recess 79b. Alternatively, in this embodiment, the positioning recess 79c may have the same shape as the first recess 79a and the second recess 79b.

[0043] like Figure 2 As shown, the stator core 70 is divided into multiple blocks 78 in the thickness direction. In this embodiment, the stator core 70 has three blocks 78 stacked on top of each other. The three blocks 78 are each constructed by stacking the same number of steel plates 79 in the thickness direction. Here, the three blocks 78 are referred to as the first block 78A, the second block 78B, and the third block 78C, respectively.

[0044] The multiple steel plates 79 included in each block 78 are stacked in a state where their circumferential positions in the positioning recesses 79c are consistent with each other. Therefore, the rolling directions of the multiple steel plates 79 in each block 78 are consistent with each other.

[0045] The first plate 78A, the second plate 78B, and the third plate 78C are rotated and stacked relative to each other. The first plate 78A is rotated 120° relative to the second plate 78B and then stacked. The second plate 78B is rotated 120° relative to the third plate 78C and then stacked. That is, in the stator core 70 of this embodiment, a plurality of steel plates 79 are rotated and stacked at a rotation angle of 120°. In the rotated and stacked stator core 70, the first recesses 79a and the second recesses 79b of the steel plates 79 included in the different plates 78 are aligned with each other in the circumferential direction. On the other hand, the positioning recesses 79c of the steel plates 79 included in the different plates 78 are different in the circumferential direction.

[0046] According to this embodiment, by stacking multiple steel plates 79 in a rotating manner, the thickness deviation of the steel plates 79 can be averaged out overall. Furthermore, the direction of the easily magnetized axis caused by the rolling of the steel plates can be averaged out throughout the stator core 70, thus suppressing torque fluctuations.

[0047] like Figure 3 As shown, the first recesses 79a of the steel plates 79 of the first plate 78A, the second plate 78B, and the third plate 78C are axially connected to each other, forming a first groove 77a. Similarly, the second recesses 79b of the steel plates 79 of the first plate 78A, the second plate 78B, and the third plate 78C are axially connected to each other, forming a second groove 77b. The first groove 77a and the second groove 77b extend axially in the radially outward surface (i.e., the outer peripheral surface 71a) of the core back 71. The ends of the first groove 77a and the second groove 77b open axially to both sides at the axial end faces of the stator core 70.

[0048] like Figure 4 As shown, welding portions 76 are provided in a plurality of first groove portions 77a and a plurality of second groove portions 77b. As described above, the outer peripheral surface 71a of the core back 71 is provided with three first groove portions 77a and three second groove portions 77b. Therefore, the outer peripheral surface 71a of the core back 71 is provided with six welding portions 76. The six welding portions 76 fix the plurality of steel plates 79 constituting the stator core portion 70 to each other along the axial direction. The welding portions 76 are provided along the entire axial length of the stator core portion 70.

[0049] In this embodiment, the six welding portions 76 are referred to as first welding portion 76A, second welding portion 76B, third welding portion 76C, fourth welding portion 76D, fifth welding portion 76E, and sixth welding portion 76F, respectively. The first welding portion 76A, second welding portion 76B, third welding portion 76C, fourth welding portion 76D, fifth welding portion 76E, and sixth welding portion 76F are arranged sequentially in the circumferential direction. That is, the plurality of welding portions 76 includes the first welding portion 76A, second welding portion 76B, third welding portion 76C, fourth welding portion 76D, fifth welding portion 76E, and sixth welding portion 76F arranged in the circumferential direction.

[0050] The odd-numbered welding portions 76 of the six welding portions 76, namely the first welding portion 76A, the third welding portion 76C, and the fifth welding portion 76E, are disposed in the first recessed portion 77a. On the other hand, the even-numbered welding portions 76 of the six welding portions 76, namely the second welding portion 76B, the fourth welding portion 76D, and the sixth welding portion 76F, are disposed in the second recessed portion 77b.

[0051] The positioning recesses 79c of each steel plate 79 of the first piece 78A, the positioning recesses 79c of each steel plate 79 of the second piece 78B, and the positioning recesses 79c of each steel plate 79 of the third piece 78C are connected axially to form positioning grooves (grooves) 75. Therefore, the outer peripheral surface 71a of the core back 71 is provided with positioning grooves 75.

[0052] The positioning groove 75 extends axially along the outer peripheral surface of the first block 78A, the second block 78B, and the third block 78C. The positioning groove 75 of the first block 78A, the second block 78B, and the third block 78C are interrupted at the boundary of the block 78 and are arranged at equal intervals in the circumferential direction.

[0053] The positioning groove 75 of any one of the first block 78A, the second block 78B, and the third block 78C functions as a keyway. A key (not shown) disposed on the inner circumferential surface of the motor housing 20 is inserted into the positioning groove 75 of any one of the first block 78A, the second block 78B, and the third block 78C. As a result, circumferential movement of the stator core 70 relative to the motor housing 20 is suppressed.

[0054] like Figure 5 As shown, the angle formed by the central axis J, the first welded portion 76A, and the second welded portion 76B when the stator core 70 is viewed axially is defined as the first angle θ1. Furthermore, the angle formed by the central axis J, the second welded portion 76B, and the third welded portion 76C when the stator core 70 is viewed axially is defined as the second angle θ2. And, the angle formed by the central axis J, the first welded portion 76A, and the third welded portion 76C is defined as the third angle θ3. In this embodiment, the first angle θ1 is 64°, the second angle θ2 is 56°, and the third angle θ3 is 120°.

[0055] In addition, such as Figure 4 As shown, the circumferential positional relationships of the first welded part 76A, the second welded part 76B, and the third welded part 76C, the circumferential positional relationships of the third welded part 76C, the fourth welded part 76D, and the fifth welded part 76E, and the circumferential positional relationships of the fifth welded part 76E, the sixth welded part 76F, and the first welded part 76A are identical. That is, the angles formed by the central axis J, the third welded part 76C, and the fourth welded part 76D, and the central axis J, the fifth welded part 76E, and the sixth welded part 76F are consistent with the first angle θ1. That is, the angles formed by the central axis J, the fourth welded part 76D, and the fifth welded part 76E, and the central axis J, the sixth welded part 76F, and the first welded part 76A are consistent with the second angle θ2.

[0056] like Figure 5 As shown, we focus on the first weld portion 76A, the second weld portion 76B, and the third weld portion 76C. In this embodiment, the first angle θ1 is larger than the second angle θ2 (θ1 > θ2). Therefore, the second weld portion 76B is positioned offset towards the third weld portion 76C from the center of the circumferential direction relative to the first weld portion 76A and the third weld portion 76C. Consequently, the circumferential distance between the first weld portion 76A and the second weld portion 76B is relatively wide, and the circumferential distance between the second weld portion 76B and the third weld portion 76C is relatively narrow. Similarly, the circumferential distance between the third weld portion 76C and the fourth weld portion 76D is relatively wide, and the circumferential distance between the fourth weld portion 76D and the fifth weld portion 76E is relatively narrow. Furthermore, the circumferential distance between the fifth weld portion 76E and the sixth weld portion 76F is relatively wide, and the circumferential distance between the sixth weld portion 76F and the first weld portion 76A is relatively narrow. Thus, the circumferential distances between the plurality of weld portions 76 are set to alternate between wide and narrow regions.

[0057] In this embodiment, the positioning groove 75 is disposed between the first welded portion 76A and the second welded portion 76B, which are circumferentially adjacent. Therefore, the positioning groove 75 is disposed between the two welded portions 76 and in an area with a relatively wide circumferential distance.

[0058] Generally, when a positioning groove 75 is provided for circumferential positioning of the stator core 70, the radial dimension of the core back 71 becomes locally smaller due to the positioning groove 75. Therefore, in the radially inner region of the positioning groove 75, the magnetic reluctance of the core back 71 increases, making it difficult for magnetic flux to pass through. On the other hand, in the steel plate 79 constituting the stator core 70, due to the heat imparted during welding, the crystallization state changes, and near the welded portion 76, the magnetic reluctance increases, making it difficult for magnetic flux to pass through.

[0059] According to this embodiment, the positioning grooves 75 are arranged in areas where the circumferential spacing of the welded portions 76 is ensured to be relatively wide. Therefore, areas where the magnetic reluctance increases due to the positioning grooves 75 and areas where the magnetic reluctance increases due to the influence of the welded portions can be arranged circumferentially further apart. As a result, the balance of magnetic reluctance in the circumferential direction of the core back 71 can be improved, thereby reducing torque fluctuations in the rotary motor 10.

[0060] Furthermore, in this embodiment, the positioning groove 75 is a notch whose opening width widens as it moves radially outward, but the shape of the positioning groove 75 is not limited to this embodiment. As the radial depth dimension of the positioning groove 75 increases, the torque fluctuation of the rotary motor 10 increases. Conversely, by making the radial depth dimension of the positioning groove 75 sufficiently small relative to the radial dimension of the core back 71, the increase in torque fluctuation caused by the positioning groove 75 can be suppressed, but the radial dimension of the rotary motor 10 becomes larger. That is, according to this embodiment, the increase in torque fluctuation accompanying the miniaturization of the rotary motor 10 can be suppressed.

[0061] In this embodiment, the positioning groove 75 is disposed on the bisecting line L of the first angle θ1. According to this embodiment, the distance between the positioning groove 75 and the welding portions 76 (i.e., the first welding portion 76A and the second welding portion 76B) located on both sides of its circumference can be maximized, and the torque fluctuation of the rotary motor 10 can be effectively reduced.

[0062] In this embodiment, the sum of the first angle θ1 and the second angle θ2, i.e., the third angle θ3, is equal to the rotational stacking angle. Therefore, the plurality of welded portions 76 and the plurality of positioning groove portions 75 are arranged in the same manner in each block 78, rotating by the third angle θ3. According to the stator core 70 of this embodiment, the plurality of welded portions 76 and the plurality of positioning groove portions 75 can be arranged periodically in the circumferential direction every rotational stacking angle, which can further suppress torque fluctuations of the rotary motor 10.

[0063] like Figure 5 As shown, in this embodiment, pole teeth 72 are arranged radially inward on the first welding portion 76A and the third welding portion 76C. Here, the center line along the extending direction of the pole teeth 72 is defined as the pole tooth center line (center line) TL. In this embodiment, the first welding portion 76A is arranged on the pole tooth center line TL of the pole teeth 72 on its radially inward side when viewed axially. Similarly, the third welding portion 76C is arranged on the pole tooth center line TL of the pole teeth 72 on its radially inward side when viewed axially.

[0064] By allowing current to flow through the coil 42 of the stator 40, a magnetic circuit is formed in the stator core 70. The magnetic flux of the magnetic circuit branches outward in the circumferential direction at the core back 71, which is radially outer of the pole teeth 72. Therefore, the magnetic flux density tends to be lower at the radially outer side of the pole teeth 72 and at the outer edge of the core back 71.

[0065] In this embodiment, by placing the weld portion 76 on the center line TL of the pole tooth 72 when viewed along the axial direction, the weld portion 76 can be placed in a part of the magnetic circuit where the magnetic flux density is relatively easy to decrease, thereby suppressing the influence of the weld portion 76 on the magnetic circuit and suppressing the torque fluctuation of the rotary motor 10.

[0066] Furthermore, in this embodiment, the first weld portion 76A, the third weld portion 76C, and the fifth weld portion 76E are described as being arranged on the pole tooth centerline TL of the pole tooth 72. However, the second weld portion 76B, the fourth weld portion 76D, and the sixth weld portion 76F may also be arranged on the pole tooth centerline TL of the pole tooth 72. And, as a variation, such as... Figure 6 As shown, the positioning groove 175 can also be disposed on the center line TL of the pole tooth 72. With the above structure, the influence of the positioning groove 175 on the magnetic circuit can be suppressed, and the torque fluctuation of the rotary motor 10 can be suppressed.

[0067] like Figure 5 As shown, a groove S is disposed on the radially inner side of the second welding portion 76B in this embodiment. Here, the radial centerline of the groove S is defined as the groove centerline (centerline) SL. In this embodiment, the second welding portion 76B is disposed on the groove centerline SL of the groove S on its radially inner side when viewed axially.

[0068] When current flows through coil 42, a circumferential magnetic circuit is formed on core back 71. When the radial dimension of core back 71 is sufficiently large, the magnetic flux density near the outer edge of core back 71 decreases. Furthermore, since the current flowing through coil 42 is alternating current, the magnetic circuit changes over time. At the outer edge of core back 71, the region radially outer of slot S is less susceptible to the time-varying magnetic circuit. Therefore, by arranging the weld portion 76 radially outer of slot S and at the outer edge of core back 71, the influence on torque fluctuations can be reduced.

[0069] In this embodiment, by placing the welded part 76 on the center line SL of the groove S when viewed along the axial direction, the influence of the welded part 76 on the magnetic circuit can be suppressed, and the torque fluctuation of the rotary motor 10 can be suppressed.

[0070] Furthermore, in this embodiment, the second weld portion 76B, the fourth weld portion 76D, and the sixth weld portion 76F among the plurality of weld portions 76 are described as being arranged on the groove center line SL of the groove S. However, the first weld portion 76A, the third weld portion 76C, and the fifth weld portion 76E may also be arranged on the groove center line SL of the groove S. And, as a variation, such as... Figure 7As shown, the positioning groove 275 can also be disposed on the center line SL of the groove S. With the above structure, the influence of the positioning groove 275 on the magnetic circuit can be suppressed, and sometimes the effect of suppressing torque fluctuations of the rotary motor 10 can be achieved.

[0071] like Figure 5 As shown, in the stator core 70 of this embodiment, the slots S through which the coil lines 43 of the same phase pass are arranged circumferentially in pairs. As described above, the plurality of slots S includes a U-phase slot S1, a V-phase slot (first slot) S2, and a W-phase slot (second slot) S3 through which the coil lines 43 of different phases pass. The positioning slot portion 75 is disposed between the center line SL of the V-phase slot S2 and the center line SL of the W-phase slot S3 when viewed axially.

[0072] Different phase voltages are applied to the coil lines 43 of different phases, and different phase currents flow through them. The pole teeth 72, located between the slots S through which the coil lines 43 of different phases pass, are unlikely to generate a large radial magnetic field. That is, in a region of the core back 71 located between the slots S through which the coil lines 43 of different phases are arranged, the magnetic flux density of the magnetic circuit decreases.

[0073] According to this embodiment, by placing the positioning groove 75 between the center lines SL of the groove S through which the coil lines 43 of different phases pass when viewed along the axial direction, the influence of the positioning groove 75 on the magnetic circuit can be suppressed, and the torque fluctuation of the rotary motor 10 can be suppressed.

[0074] Figure 8 This is a graph illustrating the simulation results of torque fluctuations in the above-described embodiments. Figure 8 In the diagram, the horizontal axis represents the first angle θ1, and the vertical axis represents the ratio of torque fluctuation relative to the maximum output of the rotating motor 10.

[0075] In the above simulation, the third angle θ3 was set to 120°, and the first angle θ1 was modified in various ways. Furthermore, the positioning groove 75 was positioned on the bisecting line of each of the first angles θ1. In the above simulation, the structure other than the modified first angles θ1 (and second angle θ2) adopted the structure of the stator core 70 of the above embodiment.

[0076] in addition, Figure 8 The results are from simulations of 24 torque fluctuations; other torque fluctuations also show the same trend.

[0077] according to Figure 8 It can be seen that in the structure of this embodiment, setting the first angle θ1 to approximately 64° best reduces torque ripple. Furthermore, in the above case, the second angle θ2 is 56°. According to... Figure 8When the first angle θ1 and the second angle θ2 are set to the same angle of 60°, the distance between the first welding part 76A and the second welding part 76B and the positioning groove part 75 becomes closer, and the torque fluctuation becomes larger.

[0078] like Figure 8 As shown, the torque fluctuation increases or decreases periodically relative to the change in the first angle θ1. This increase or decrease is caused by the phase relationship between the positioning slots 75, which are located on the bisecting line of the first angle θ1, and each slot S. Figure 8 Within the range shown, the first angle θ1, which represents the minimum torque ripple, is between 60° and 67.5° and between 75° and 82.5°. When the first angle θ1 is within the range described above, the positioning slot 75 is positioned radially outward of the pole tooth 72. Therefore, torque ripple is reduced. Furthermore, when the first angle θ1 is between 60° and 67.5°, the positioning slot 75 is positioned between the slots S through which the coil lines 43 of different phases pass, further reducing torque ripple.

[0079] The embodiments of the present invention have been described above. However, each structure and combination thereof in each embodiment is an example, and structural additions, omissions, substitutions, and other changes can be made without departing from the spirit of the present invention. Moreover, the present invention is not limited to the embodiments.

[0080] For example, the rotary motor 10 is not limited to a motor, but can also be a generator. The application of the rotary motor 10 is not particularly limited. For example, the rotary motor can be installed in a vehicle for purposes other than rotating an axle, or in equipment other than a vehicle. The posture when using the rotary motor is not particularly limited. The central axis of the rotary motor can also extend in a vertical direction.

[0081] In the above embodiment, the internal rotor type rotary motor 10 was described, but the same structure can also be used in the external rotor type rotary motor 10. Furthermore, in the above embodiment, the case where the welding portion 76 is provided within the recess was described. However, the welding portion can also be directly provided on the outer peripheral surface of the stator core.

Claims

1. A stator core, wherein the stator core is a stator core formed by stacking multiple steel plates, comprising: A ring-shaped core back, with the core back centered on the central axis; as well as Multiple pole teeth, the multiple pole teeth extending radially from the back of the core. The radially facing side of the core back is provided with: Multiple welded sections, the multiple welded sections extending axially and fixing the multiple steel plates together; and The groove extends axially. The plurality of welded portions include a first welded portion, a second welded portion, and a third welded portion arranged sequentially along the circumference. The angle formed by the central axis, the first welded part, and the second welded part is greater than the angle formed by the central axis, the second welded part, and the third welded part. The groove is positioned between the first weld portion and the second weld portion, which are adjacent in the circumferential direction. The stator core has multiple blocks stacked along the thickness direction, and the slots included in the different blocks are arranged at equal intervals in the circumferential direction.

2. The stator core according to claim 1, wherein, The groove is positioned on the bisecting line of the angle formed by the central axis, the first welded portion, and the second welded portion.

3. The stator core according to claim 1 or 2, wherein, Multiple steel plates are stacked in a rotating stacking angle. The angle formed by the central axis, the first welded part, and the third welded part is equal to the rotational stacking angle.

4. The stator core according to claim 1 or 2, wherein, The welded portion or the groove portion is positioned on the center line of the pole tooth when viewed axially.

5. The stator core according to claim 1 or 2, wherein, The welded portion or the groove portion is positioned on the center line of the groove between adjacent pole teeth when viewed axially.

6. The stator core according to claim 1 or 2, wherein, The circumferentially adjacent pole teeth are provided with grooves between each other. The plurality of slots includes a first slot and a second slot through which coil wires of different phases pass. The groove is positioned between the centerline of the first groove and the centerline of the second groove when viewed axially.

7. A rotary electric motor, comprising: Stator, said stator having a stator core as described in any one of claims 1 to 6; as well as The rotor is capable of rotating relative to the stator.

8. A driving device, comprising: The rotary motor according to claim 7; as well as A transmission device, which is connected to the rotor.

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