CN110036552B - Stator core component piece and rotating electrical machine - Google Patents

Abstract

A plurality of stator core constituting pieces (11a) constituting an annular stator core, characterized in that the stator core constituting pieces are composed of a back yoke (11a1) and teeth (11a2) provided on the inner peripheral side of the back yoke (11a1), the teeth (11a2) have a base portion (11a22) extending in the central axis direction from the circumferential center of the back yoke (11a1) and a tip portion (11a21) provided on the inner peripheral side of the base portion (11a22), the teeth (11a2) form a groove (3) having a shape in which the width in the circumferential direction changes stepwise toward the outer side in the radial direction of the stator core on the inner peripheral portion of the tip portion (11a21), the 2 nd width is narrower than the 1 st width when the width in the radial direction from the 1 st intersection point (IP1) to the 2 nd intersection point (IP2) is set as the 2 nd width, and the 2 nd width in the radial direction from the 1 st intersection point (IP1) to the 3 rd intersection point (IP3) is set as the 2 nd width.

Description

Stator Core Constituents and Rotary Electric Machines

technical field

The present invention relates to a stator core configuration sheet and a rotating electrical machine including a back yoke and a plurality of teeth provided on the inner peripheral side of the back yoke.

Background technique

The stator core of the rotating electrical machine disclosed in Patent Document 1 has a yoke and a plurality of teeth provided on the yoke, and in order to reduce vibration caused by torque pulsation, radially inner sides of the teeth are formed toward the center of the stator core An open incision is made. The width of the notch in the radial direction of the rotary electric machine is wider than the width of the notch in the circumferential direction of the central axis of the rotary electric machine.

Patent Document 1: Japanese Patent No. 4114372

SUMMARY OF THE INVENTION

However, in the stator core disclosed in Patent Document 1, there is a problem that only the cogging torque caused by the combination of the number of magnetic poles and the number of slots and the cogging caused by the fluctuation of the magnetic force of the magnet can be reduced one of the torques.

The present invention has been made in view of the above-mentioned circumstances, and an object thereof is to obtain a stator core capable of reducing both cogging torque due to the combination of the number of magnetic poles and the number of slots and cogging torque due to fluctuations in the magnetic force of the magnets constitute a slice.

In order to solve the above-mentioned problems and achieve the object, a stator core constituting sheet of the present invention comprises a plurality of stator core constituting sheets to constitute an annular stator core, and the stator core constituting sheet is characterized in that the stator core constituting sheet is composed of a rear The yoke is composed of teeth provided on the inner peripheral side of the back yoke, the teeth have a base extending in the central axis direction from the circumferential center of the back yoke, and a front end provided on the inner peripheral side of the base, and the inner peripheral portion of the front end , forming a groove of a shape whose width in the circumferential direction changes stepwise toward the outer side in the radial direction of the stator core, and in a cross section perpendicular to the central axis direction, a virtual line extending from the curve of the inner peripheral surface of the front end portion to the groove The width in the radial direction of the curve and the first intersection of the bisector that bisects the front end in the circumferential direction and the boundary between the base and the front end and the second intersection of the bisector is the first width, When the width in the radial direction from the first intersection to the third intersection of the bottom surface of the groove and the bisector is the second width, the second width is narrower than the first width.

effect of invention

The stator core constituent sheet according to the present invention has the effect of reducing both cogging torque caused by the combination of the number of magnetic poles and the number of slots and cogging torque caused by fluctuations in the magnetic force of the magnets.

Description of drawings

1 is a cross-sectional view in a direction orthogonal to the axial direction of a central axis of a rotary electric machine having a stator core according to Embodiment 1. FIG.

FIG. 2 is a perspective view of the stator core constituent sheet shown in FIG. 1 .

FIG. 3 is a view of the stator core constituent piece shown in FIG. 1 viewed from the end face side of the stator core in the axial direction of the central axis of the rotating electrical machine.

FIG. 4 is a diagram showing a first modification of the stator core configuration sheet shown in FIG. 1 .

FIG. 5 is a diagram showing a second modification of the stator core configuration sheet shown in FIG. 1 .

FIG. 6 is a diagram showing a third modification of the stator core configuration sheet shown in FIG. 1 .

FIG. 7 is a diagram showing a fourth modification of the stator core configuration sheet shown in FIG. 1 .

FIG. 8 is a diagram showing a fifth modification of the stator core configuration sheet shown in FIG. 1 .

FIG. 9 is a diagram showing a sixth modification of the stator core configuration sheet shown in FIG. 1 .

FIG. 10 is a diagram showing a seventh modification of the stator core configuration sheet shown in FIG. 1 .

FIG. 11 is a diagram showing an eighth modification of the stator core configuration sheet shown in FIG. 1 .

12 is a perspective view of a stator core according to Embodiment 2. FIG.

13 is a first diagram showing the relationship between the cogging torque generated in the rotors according to Embodiments 1 and 2 and the width of the slots.

14 is a second diagram showing the relationship between the cogging torque generated in the rotors according to Embodiments 1 and 2 and the width of the slots.

Detailed ways

Hereinafter, the stator core constituent sheet and the rotating electrical machine according to the embodiment of the present invention will be described in detail based on the drawings. In addition, this invention is not limited by this Embodiment.

Embodiment 1.

1 is a cross-sectional view in a direction orthogonal to the axial direction of a central axis of a rotary electric machine having a stator core according to Embodiment 1. FIG. FIG. 2 is a perspective view of the stator core constituent sheet shown in FIG. 1 . FIG. 3 is a view of the stator core constituent piece shown in FIG. 1 viewed from the end face side of the stator core in the axial direction of the central axis of the rotating electrical machine.

The rotating electrical machine 100 shown in FIG. 1 includes a stator 1 and a rotor 2 provided inside the stator 1 . The rotating electrical machine 100 is a 10-pole 12-slot electric motor.

The rotor 2 includes a rotor core 21 , a shaft 22 provided in the rotor core 21 , and a plurality of permanent magnets 23 . The number of poles 24 of the rotor 2 produced by the permanent magnets 23 is ten.

The rotor core 21 is formed by stacking a plurality of thin plates punched out in an annular shape from an electromagnetic steel sheet base material (not shown) in the axial direction of the central axis AX of the annular stator core 11 . The axial direction of the central axis AX of the stator core 11 is the direction indicated by the arrow D1 in FIG. 2 , and is equal to the axial direction of the central axis of the rotating electrical machine 100 . The plurality of sheets are fixed to each other by riveting, welding or gluing. A gap is ensured between the rotor core 21 and the stator 1 . The plurality of permanent magnets 23 may be embedded in the rotor core 21 or may be provided on the outer peripheral surface of the rotor core 21 . The shaft 22 is fixed to the axial center portion of the rotor core 21 by shrink fitting, cold press fitting, or press fitting.

The stator 1 includes a stator core 11 formed by connecting a plurality of stator core constituent pieces 11 a in an annular shape, and a coil 12 formed by winding a coil for generating a rotating magnetic field around the stator core 11 . The stator core configuration sheet 11a is formed by stacking a plurality of thin plates punched out in a T-shape from an electromagnetic steel sheet base material (not shown) in the axial direction D1. The plurality of sheets are fixed to each other by riveting, welding or gluing. The cross-sectional shape of the stator core constituent piece 11a perpendicular to the axial direction D1 is symmetrical with respect to the bisector CP10 of the cross-sectional shape. The bisecting line CP10 is a line which bisects the front-end|tip part 11a21 in the circumferential direction D2. It is a line extending in the direction of the central axis AX from the circumferential center 11a111 of the back yoke 11a1. The circumferential center 11a111 is located on the line 8 that bisects the width of the outer peripheral portion 11a11 of the back yoke 11a1 in the circumferential direction D2.

Each of the plurality of stator core configuration pieces 11a has a back yoke 11a1 and teeth 11a2 provided on the inner peripheral side 11a1a of the back yoke 11a1. The teeth 11a2 extend from the back yoke 11a1 toward the center axis AX. The teeth 11a2 have a base portion 11a22 extending in the direction of the central axis AX from the circumferential center 11a111 of the back yoke 11a1, and a front end portion 11a21 provided on the inner peripheral side of the base portion 11a22. A line shown by reference numeral 11a22a indicates the boundary between the base portion 11a22 and the front end portion 11a21. Each of the plurality of teeth 11a2 is spaced apart in the circumferential direction D2 of the stator 1 and arranged radially. The circumferential direction D2 is equal to the circumferential direction of the stator core 11 . On the stator 1, the slot 11a3 is formed in the area|region between the adjacent teeth 11a2.

2 and 3 show one of the plurality of stator core configuration pieces 11a shown in FIG. 1 . The teeth 11a2 have a base portion 11a22 and a front end portion 11a21 extending from the back yoke 11a1 toward the central axis AX. The front end portion 11a21 is formed on the center side of the stator core of the teeth 11a2 in the radial direction D3. An attachment root portion 11a23 is formed between the base portion 11a22 and the front end portion 11a21. The mounting root portion 11a23 is located at the boundary 11a22a of the base portion 11a22 and the front end portion 11a21. The front-end|tip part 11a21 is the shape extended in the circumferential direction D2. The inner peripheral portion 4 of the front end portion 11a21 faces the rotor 2 shown in FIG. 1 .

The groove 3 is formed in the inner peripheral part 4 of the front-end|tip part 11a21. The groove 3 is formed in the center part in the circumferential direction D2 of the front-end|tip part 11a21. The groove 3 is constituted by the first groove 31 and the second groove 32, and has a shape in which the width in the circumferential direction D2 is gradually narrowed toward the outer side in the radial direction D3.

Each of the first groove 31 and the second groove 32 has a shape recessed toward the outer peripheral portion 11 a 11 of the back yoke 11 a 1 from the central axis AX shown in FIG. 1 . The first grooves 31 extend from one end face of the teeth 11a2 in the axial direction D1 of the central axis AX of the stator core 11 to the other end face. The second groove 32 is formed at the center portion in the circumferential direction D2 of the first groove 31 and is formed on the outer side in the radial direction D3 of the first groove 31 . The second groove 32 extends from one end face of the tooth 11a2 in the axial direction D1 of the central axis AX of the stator core 11 to the other end face.

The corner portion 5 is formed at the front end portion 11a21. The corner portion 5 is formed between the inner peripheral portion 4 of the front end portion 11 a 21 and the first groove 31 .

As shown in FIG. 3 , the width in the circumferential direction D2 of the first groove 31 is W1, the width in the circumferential direction D2 of the base portion 11a22 of the tooth 11a2 is W2, and the circumferential direction D2 of the second groove 32 is When the width of W3 is set, the width W1 is narrower than the width W2 and wider than the width W3.

When the width from the bottom surface 32a of the second groove 32 in the radial direction D3 to the corner 5 is W4, and the width from the mounting base 11a23 in the radial direction D3 to the first intersection IP1 is W5, the width W4 is narrower than width W5. The width W4 is equal to the maximum depth of the groove 3 . The width W5 is equal to the radial minimum thickness of the front end portion 11a21 from the inner peripheral portion 4 of the front end portion 11a21 to the boundary 11a22a of the front end portion 11a21 and the base portion 11a22. That is, the maximum depth of the groove 3 is shallower than the radial minimum thickness of the front end portion 11a21. The first intersection IP1 is the intersection of the bisector CP10 and the virtual curve 11a4. The virtual curve 11a4 is a line extending the curve of the inner peripheral surface of the front end portion 11a21 to the groove 3 in a cross section perpendicular to the central axis AX direction.

Let the width in the radial direction from the first intersection IP1 to the second intersection IP2 of the boundary 11a22a and the bisector CP10 be the first width (W5), and the width from the first intersection IP1 to the third intersection IP3 When the width in the radial direction is the second width (W4), the second width is narrower than the first width. The third intersection IP3 is the intersection of the bottom surface 32a of the groove 3 and the bisector CP10.

According to the stator core 11 according to the first embodiment, the width of the slots 3 in the circumferential direction D2 is gradually narrowed toward the outer side in the radial direction D3, thereby reducing the number of magnetic poles and the number of slots in combination. Both the cogging torque and the cogging torque due to the fluctuation of the magnetic force of the permanent magnet 23 . The cogging torque generated by the combination of the number of magnetic poles and the number of slots is reduced by adjusting the width W1 of the first slot 31 , and the cogging torque generated by the fluctuation of the magnetic force of the permanent magnet 23 is reduced by adjusting the width W1 of the second slot 31 . The width W3 of 32 is adjusted and reduced.

Specifically, in the case of a 10-pole 12-slot rotary electric machine, the cogging torque generated by the combination of the number of magnetic poles and the number of slots is 60 times and 120 times when the rotor 2 shown in FIG. 1 makes one rotation. This number of times occurs. 60 times is the least common multiple of 10 and 12. In addition, in the case of a 10-pole 12-slot rotating electric machine, the cogging torque generated by the fluctuation of the magnetic force of the permanent magnet 23 is 12 times and 24 times when the rotor 2 shown in FIG. 1 makes one rotation. generated times. 12 times and 24 times are integer multiples of the number of slots.

According to the stator core 11 according to the first embodiment, by adjusting the width W1 of the first slot 31, the cogging torque generated at times such as 60 times and 120 times is reduced, and by adjusting the width W3 of the second slot 32 Adjustment so that the cogging torque of 12 times is reduced. In addition, in the stator core 11 according to the first embodiment, by providing the second slot 32, the magnetic permeability of the 24th order increases and the cogging torque of the 24th order increases, but the width in the circumferential direction D2 of the slot 3 is increased toward The radial direction D3 is changed in steps, and the change in the magnetic permeability is smoothed, so that the cogging torque of the 24th order is reduced.

In addition, in the stator core 11 shown in FIG. 1 , the width W4 from the bottom surface 32a of the second groove 32 in the radial direction D3 to the corner portion 5 is the first intersection point from the mounting base portion 11a23 in the radial direction D3 The width W5 up to IP1 is narrower than that, thereby preventing a decrease in torque due to a decrease in the gap magnetic flux density. In addition, in the stator core 11 shown in FIG. 1 , since the second grooves 32 are formed on the bottom surfaces of the first grooves 31, the first grooves 31 and the second grooves are formed separately from the inner peripheral portion 4 of the front end portion 11a21. Compared with the case of 32, the punching by the die becomes easier. In addition, the stator core 11 shown in FIG. 1 is formed with the slots 3 having a shape in which the relationship of W1>W3 is established, so that the reduction of the gap magnetic flux density and the reduction of the torque are suppressed.

In addition, the slot 3 of the stator core configuration piece 11a may be formed in a shape in which the relationship of W1>W3×2 holds. With the above-described configuration, the reduction in the gap magnetic flux density and the reduction in torque are further suppressed compared with the case where the grooves 3 having a shape in which the relationship W1 > W3 is established are formed.

FIG. 4 is a diagram showing a first modification of the stator core configuration sheet shown in FIG. 1 . Slots 3A are formed in the teeth 11a2 of the stator core configuration piece 11A shown in FIG. 4 instead of the slots 3 shown in FIG. 3 . The groove 3A is formed at the center portion in the circumferential direction D2 of the distal end portion 11a21 in the inner peripheral portion 4 of the distal end portion 11a21. The groove 3A includes a first groove 31 , a second groove 32 and a third groove 33 . The groove 3A has a shape in which the width in the circumferential direction D2 gradually narrows toward the outer side in the radial direction D3, and the width in the circumferential direction D2 changes in three steps.

The third groove 33 is formed at the center portion of the second groove 32 in the circumferential direction D2. The third groove 33 extends from one end face of the tooth 11a2 in the axial direction D1 of the central axis AX of the stator core 11 shown in FIG. 1 to the other end face.

When the width in the circumferential direction D2 of the second groove 32 is W3 and the width in the circumferential direction D2 of the third groove 33 is W6, the width W6 is narrower than the width W3. In addition, when the width from the bottom surface 33a of the third groove 33 in the radial direction D3 to the corner portion 5 is W4, and the width from the mounting base 11a23 in the radial direction D3 to the first intersection IP1 is W5 , the width W4 is narrower than the width W5. The width W4 is equal to the maximum depth of the groove 3A. The width W5 is equal to the radial minimum thickness of the front end portion 11a21 from the inner peripheral portion 4 of the front end portion 11a21 to the boundary 11a22a of the front end portion 11a21 and the base portion 11a22. That is, the maximum depth of the groove 3A is shallower than the radial minimum thickness of the front end portion 11a21.

Let the width in the radial direction from the first intersection IP1 to the second intersection IP2 of the boundary 11a22a and the bisector CP10 be the first width (W5), and the width from the first intersection IP1 to the third intersection IP3 When the width in the radial direction is the second width (W4), the second width is narrower than the first width. The third intersection IP3 is the intersection of the bottom surface 33a of the groove 3A and the bisector CP10.

According to the stator core 11 using the stator core configuration sheet 11A shown in FIG. 4 , the cogging torque is generated at integer multiples of the number of slots such as 12 times, 24 times, and 60 times due to fluctuations in the magnetic force of the permanent magnets 23 . decreases, and the cogging torque generated at times other than an integer multiple of the number of slots also decreases.

FIG. 5 is a diagram showing a second modification of the stator core configuration sheet shown in FIG. 1 . Slots 3B are formed in the teeth 11a2 of the stator core configuration piece 11B shown in FIG. 5 instead of the slots 3 shown in FIG. 3 . The groove 3B is formed in the center part in the circumferential direction D2 of the front end part 11a21 in the inner peripheral part 4 of the front end part 11a21. The groove 3B has a shape in which the width in the circumferential direction D2 gradually increases toward the outer side in the radial direction D3. In other words, the groove 3B has a shape in which the width in the circumferential direction D2 gradually narrows toward the inner side in the radial direction D3.

Let the width in the circumferential direction D2 of the groove 3B on the back yoke 11a1 side be W1, and let the width in the circumferential direction D2 of the base 11a22 of the teeth 11a2 be W2, and let the circumferential direction of the groove 3B opposite to the back yoke 11a1 be W2. When the width on D2 is set to W3, the width W1 is narrower than the width W2 and wider than the width W3.

The corner portion 5 is formed at the front end portion 11a21. The corner portion 5 is formed between the inner peripheral portion 4 of the front end portion 11a21 and the groove 3B. When the width from the bottom surface 3B1 of the groove 3B in the radial direction D3 to the corner 5 is W4, and the width from the mounting base 11a23 in the radial direction D3 to the first intersection IP1 is W5, the width W4 is larger than The width W5 is narrow. The width W4 is equal to the maximum depth of the groove 3B. The width W5 is equal to the radial minimum thickness of the front end portion 11a21 from the inner peripheral portion 4 of the front end portion 11a21 to the boundary 11a22a of the front end portion 11a21 and the base portion 11a22. That is, the maximum depth of the groove 3B is shallower than the radial minimum thickness of the front end portion 11a21.

Let the width in the radial direction from the first intersection IP1 to the second intersection IP2 of the boundary 11a22a and the bisector CP10 be the first width (W5), and the width from the first intersection IP1 to the third intersection IP3 When the width in the radial direction is the second width (W4), the second width is narrower than the first width. The third intersection IP3 is the intersection of the bottom surface 3B1 of the groove 3B and the bisector CP10.

According to the stator core 11 using the stator core configuration sheet 11B shown in FIG. 5 , the cogging torque is generated at times of integral multiples of the number of slots, such as 12 times, 24 times, and 60 times, due to fluctuations in the magnetic force of the permanent magnets 23 . decreases, and the cogging torque generated at times other than an integer multiple of the number of slots also decreases. In addition, according to the stator core 11 using the stator core configuration sheet 11B, the width W1 is wider than the width W3, so the leakage magnetic flux between the slots is reduced, and the reduction of torque under high load is suppressed. Specifically, in the rotating electrical machine 100 under a high load, the leakage magnetic flux that flows through the adjacent teeth 11a2 via the tip portion 11a21 increases. Therefore, the reduction in torque becomes large in the rotary electric machine 100 having a large slot opening width. When the width W1 is wider than the width W3, the leakage magnetic flux flowing in the adjacent teeth 11a2 through the tip portion 11a21 is suppressed in the stepped portion of the slot, so that the leakage magnetic flux becomes smaller and the decrease in torque becomes smaller. The slot upper stepped portion is a portion corresponding to a region on the side of the attachment base portion 11a23 compared to the front end portion 11a21 in the slot 11a3 shown in FIG. 2 .

FIG. 6 is a diagram showing a third modification of the stator core configuration sheet shown in FIG. 1 . In the teeth 11a2 of the stator core configuration piece 11C shown in FIG. 6 , a slot group 3C is formed instead of the slot 3 shown in FIG. 3 . The groove group 3C is formed in the center part in the circumferential direction D2 of the front end part 11a21 in the inner peripheral part 4 of the front end part 11a21. The groove group 3C includes two first grooves 31 formed in the inner peripheral portion 4 of the distal end portion 11a21 and second grooves 32 formed in the inner peripheral portion 4 of the distal end portion 11a21.

The second grooves 32 are provided between the two first grooves 31, and the two first grooves 31 and the second grooves 32 are arranged in the circumferential direction D2 in the order of the first grooves 31, the second grooves 32, and the first grooves 31. . The first grooves 31 and the second grooves 32 are arranged to be separated from each other in the circumferential direction D2. A protrusion 41 is formed between the first groove 31 and the second groove 32 .

A corner portion 51 is formed between the inner peripheral portion 4 of the front end portion 11 a 21 and the first groove 31 . A corner portion 52 is formed between the inner peripheral portion 4 of the front end portion 11 a 21 and the second groove 32 .

The width from the bottom surface 31a of the first groove 31 in the radial direction D3 to the corner 51 is W41, and the width from the bottom surface 32a of the second groove 32 in the radial direction D3 to the corner 52 is W42 , when the width from the mounting base 11a23 in the radial direction D3 to the first intersection IP1 is W5, the width W42 is narrower than the width W5 and wider than the width W41. The width W42 is equal to the maximum depth of the second groove 32 . The width W5 is equal to the radial minimum thickness of the front end portion 11a21 from the inner peripheral portion 4 of the front end portion 11a21 to the boundary 11a22a of the front end portion 11a21 and the base portion 11a22. That is, the maximum depth of the second groove 32 is shallower than the radial minimum thickness of the distal end portion 11a21.

Let the width in the radial direction from the first intersection IP1 to the second intersection IP2 of the boundary 11a22a and the bisector CP10 be the first width (W5), and the width from the first intersection IP1 to the third intersection IP3 When the width in the radial direction is the second width (W4), the second width is narrower than the first width. The third intersection IP3 is the intersection of the bottom surface 32a of the second groove 32 and the bisector CP10.

Let the width from one corner portion 51 to the other corner portion 51 in the circumferential direction D2 be W1, the width of the first groove 31 in the circumferential direction D2 be W11, and the circumferential direction D2 of the base portion 11a22 of the tooth 11a2 When the width of the second groove 32 in the circumferential direction D2 is W3, the width W1 is narrower than the width W2, and the width W11 is narrower than the width W2 and wider than the width W3.

Similar to the grooves 3 shown in FIG. 3 , the groove group 3C has a shape in which the width in the circumferential direction D2 is gradually narrowed toward the outer side in the radial direction D3 . According to the stator core 11 using the stator core configuration sheet 11C shown in FIG. 6 , by adjusting the width W11 of the first slot 31 , the cogging torque generated by the combination of the number of magnetic poles and the number of slots is reduced. The width W3 of the slot 32 is adjusted so that the cogging torque due to the fluctuation of the magnetic force of the permanent magnet 23 is reduced. In addition, when the shape of the first groove 31 and the second groove 32 is not a simple shape such as a circle and a rectangle, but a complex shape such as a star shape and a V shape, the electromagnetic steel sheet base material may be punched. The shape of the die to be cut becomes complicated, the manufacture of the die becomes difficult, and the blanking of the electromagnetic steel sheet base material becomes difficult. According to the stator core 11 using the stator core configuration sheet 11C shown in FIG. 6 , the shapes of the first slots 31 and the second slots 32 constituting the slot group 3C can be made into simple rectangles, so that the production of the mold is easy. Fabrication of the core 11 is easy.

In FIGS. 3 to 6 , an example in which a groove portion having a shape in which the width in the circumferential direction D2 is gradually narrowed toward the outer or inner side in the radial direction D3 has been described has been described. Next, an example in which a through hole having a shape in which the width in the circumferential direction D2 is gradually narrowed toward the outer side in the radial direction D3 will be described.

FIG. 7 is a diagram showing a fourth modification of the stator core configuration sheet shown in FIG. 1 . In the teeth 11 a 2 of the stator core configuration piece 11D shown in FIG. 7 , through holes 6 are formed instead of the slots 3 shown in FIG. 3 . The through-hole 6 is formed in the center part in the circumferential direction D2 of the front-end|tip part 11a21. The through hole 6 penetrates one end surface and the other end surface of the tooth 11a2 in the axial direction D1 shown in FIG. 1 .

The through hole 6 includes a first region 6a having a width W1 in the circumferential direction D2 narrower than the width W2 of the base portion 11a22, and a second region 6b having a width W3 narrower than the width W1 in the circumferential direction D2. The second region 6b communicates with the first region 6a, and is formed at the center portion in the circumferential direction D2 of the first region 6a. The 2nd area|region 6b is formed in the base part 11a22 side rather than the 1st area|region 6a.

The width from the end face 6d of the second region 6b in the radial direction D3 to the end face 6c of the first region 6a in the radial direction D3 on the opposite side to the teeth 11a2 is set to W4, and from the mounting base in the radial direction D3 When the width from 11a23 to the first intersection IP1 is set to W5, the width W4 is narrower than the width W5. The width W4 is equal to the maximum depth of the through hole 6 from the inner peripheral portion 4 of the front end portion 11a21 toward the outer side in the radial direction. The width W5 is equal to the radial minimum thickness of the front end portion 11a21 from the inner peripheral portion 4 of the front end portion 11a21 to the boundary 11a22a of the front end portion 11a21 and the base portion 11a22. That is, the maximum depth of the through hole 6 is shallower than the radial minimum thickness of the distal end portion 11a21. The first intersection IP1 is the intersection of the bisector CP10 and the inner peripheral surface of the tip portion 11a21.

Let the width in the radial direction from the first intersection IP1 to the second intersection IP2 of the boundary 11a22a and the bisector CP10 be the first width (W5), and the width from the first intersection IP1 to the third intersection IP3 When the width in the radial direction is the second width (W4), the second width is narrower than the first width. The third intersection IP3 is the intersection of the radially outer end surface of the through hole 6 and the bisector CP10.

As described above, the width of the through hole 6 in the circumferential direction D2 is gradually narrowed toward the outer side in the radial direction D3. According to the stator core 11 using the stator core configuration sheet 11D shown in FIG. 7, the cogging torque generated by the combination of the number of magnetic poles and the number of slots is reduced by adjusting the width W1 of the first region 6a, and the permanent magnet The cogging torque generated by the fluctuation of the magnetic force of 23 is reduced by adjusting the width W3 of the second region 6b. In addition, according to the stator core 11 using the stator core configuration sheet 11D shown in FIG. 7 , instead of providing a plurality of through holes in one tooth 11 a 2 , only one through hole 6 may be formed. made easy. In addition, in the stator core 11 using the stator core configuration sheet 11D shown in FIG. 7, the slots 3, 3A, 3B and the slot group 3C shown in FIG. 3 to FIG. Compared with the case of 3B and the slot group 3C, the roundness of the inner diameter of the stator does not decrease due to the manufacturing fluctuation of the through hole 6, and the roundness of the stator core 11 is improved.

FIG. 8 is a diagram showing a fifth modification of the stator core configuration sheet shown in FIG. 1 . In the teeth 11a2 of the stator core configuration piece 11E shown in FIG. 8 , a through-hole group 6A is formed instead of the slot 3 shown in FIG. 3 . The through-hole group 6A is formed in the center part in the circumferential direction D2 of the front-end|tip part 11a21. The through-hole group 6A includes two first through-holes 61 and second through-holes 62 . The second through-hole 62 is provided between the two first through-holes 61 , and the two first through-holes 61 and the second through-hole 62 are arranged in the circumferential direction D2 according to the first through-hole 61 , the second through-hole 62 and the second through-hole 62 . 1 through holes 61 are arranged in order. The first through holes 61 and the second through holes 62 are arranged to be separated from each other in the circumferential direction D2.

In FIG. 8 , regarding the position of the end face of the first through hole 61 in the radial direction D3 on the opposite side to the back yoke 11a1, the portion closest to the second through hole 62 is the distance between the second through hole 62 in the radial direction D3 The position of the end surface on the opposite side of the back yoke 11a1 is the same.

The width from the end face on the back yoke 11a1 side of the first through hole 61 in the radial direction D3 to the end face on the opposite side to the back yoke 11a1 of the first through hole 61 in the radial direction D3 is W41, The width from the end face of the second through hole 62 on D3 on the back yoke 11a1 side to the end face of the second through hole 62 on the radial direction D3 opposite to the back yoke 11a1 is W42, When the width from the attachment base 11a23 to the first intersection IP1 is set to W5, the width W42 is narrower than the width W5 and wider than the width W41. The width W42 is equal to the maximum depth of the second through hole 62 from the inner peripheral portion 4 of the distal end portion 11a21 toward the outer side in the radial direction. The width W5 is equal to the radial minimum thickness of the front end portion 11a21 from the inner peripheral portion 4 of the front end portion 11a21 to the boundary 11a22a of the front end portion 11a21 and the base portion 11a22. That is, the maximum depth of the second through hole 62 is shallower than the radial minimum thickness of the distal end portion 11a21. The first intersection IP1 is the intersection of the bisector CP10 and the inner peripheral surface of the tip portion 11a21.

Let the width in the radial direction from the first intersection IP1 to the second intersection IP2 of the boundary 11a22a and the bisector CP10 be the first width (W5), and the width from the first intersection IP1 to the third intersection IP3 When the width in the radial direction is the second width (W4), the second width is narrower than the first width. The third intersection IP3 is the intersection between the radially outer end surface of the second through hole 62 and the bisector CP10.

W1 is the width from one end face of one first through hole 61 in the circumferential direction D2 to the other end face of the other first through hole 61 in the circumferential direction D2, and the circumferential direction of the first through hole 61 is defined as W1. When the width in the circumferential direction D2 of the tooth 11a2 is W11, the width in the circumferential direction D2 of the base portion 11a22 of the tooth 11a2 is W2, and the width in the circumferential direction D2 of the second through hole 62 is W3, the width W1 is narrower than the width W2, The width W11 is narrower than the width W2 and wider than the width W3.

As described above, the through-hole group 6A has a shape in which the width in the circumferential direction D2 is gradually narrowed toward the outer side in the radial direction D3. According to the stator core 11 using the stator core configuration sheet 11E shown in FIG. 8 , the cogging torque generated by the combination of the number of magnetic poles and the number of slots is reduced by adjusting the width W11 of the first through hole 61 . The cogging torque generated by the fluctuation of the magnetic force of the magnet 23 is reduced by adjusting the width W3 of the second through hole 62 .

In addition, according to the stator core 11 using the stator core configuration sheet 11E, the first through holes 61 and the second through holes constituting the through hole group 6A can be formed in the same manner as the first slot 31 and the second slot 32 shown in FIG. 6 . Since the shape of 62 is a simple rectangle, it is easy to manufacture a mold and also to manufacture the stator core 11 . In addition, in the stator core 11 using the stator core configuration sheet 11E shown in FIG. 8, the slots 3, 3A, 3B and the slot group 3C shown in FIG. 3 to FIG. Compared with the case of 3B and the slot group 3C, the roundness of the inner diameter of the stator does not decrease due to the manufacturing fluctuation of the through-hole group 6A, and the roundness of the stator core 11 is improved.

FIG. 9 is a diagram showing a sixth modification of the stator core configuration sheet shown in FIG. 1 . A through-hole group 6B is formed in the teeth 11a2 of the stator core configuration piece 11F shown in FIG. 9 instead of the slots 3 shown in FIG. 3 . The through-hole group 6B is formed in the center part in the circumferential direction D2 of the front-end|tip part 11a21. The through-hole group 6B is composed of a first through-hole 61 and a second through-hole 62 arranged in the radial direction D3. The first through holes 61 and the second through holes 62 are arranged to be separated from each other in the radial direction D3. The first through hole 61 is provided close to the inner peripheral portion 4 of the front end portion 11a21 , and the second through hole 62 is provided on the back yoke 11a1 side of the first through hole 61 and at the center portion of the first through hole 61 in the circumferential direction D2 .

W4 is the width from the end face of the second through hole 62 on the back yoke 11a1 side in the radial direction D3 to the end face of the first through hole 61 on the opposite side of the back yoke 11a1 in the radial direction D3, and When the width from the mounting base 11a23 on D3 to the first intersection IP1 is set to W5, the width W4 is narrower than the width W5. The width W4 is equal to the maximum width from the radially inner side of the first through hole 61 to the radially outer side of the second through hole 62 . The width W5 is equal to the radial minimum thickness of the front end portion 11a21 from the inner peripheral portion 4 of the front end portion 11a21 to the boundary 11a22a of the front end portion 11a21 and the base portion 11a22. That is, the maximum width from the radially inner side of the first through hole 61 to the radially outer side of the second through hole 62 is narrower than the radial minimum thickness of the distal end portion 11 a 21 . The first intersection IP1 is the intersection of the bisector CP10 and the inner peripheral surface of the tip portion 11a21.

Let the width in the radial direction from the first intersection IP1 to the second intersection IP2 of the boundary 11a22a and the bisector CP10 be the first width (W5), and the width from the first intersection IP1 to the third intersection IP3 When the width in the radial direction is the second width (W4), the second width is narrower than the first width. The third intersection IP3 is the intersection between the radially outer end surface of the second through hole 62 and the bisector CP10.

Let the width in the circumferential direction D2 of the first through hole 61 be W1, the width in the circumferential direction D2 of the base portion 11a22 of the teeth 11a2 in the circumferential direction D2 be W2, and the width in the circumferential direction D2 of the second through hole 62 shall be At W3, the width W1 is narrower than the width W2 and wider than the width W3.

As described above, the through-hole group 6B has a shape in which the width in the circumferential direction D2 is gradually narrowed toward the outer side in the radial direction D3. According to the stator core 11 using the stator core configuration sheet 11F shown in FIG. 9 , the cogging torque generated by the combination of the number of magnetic poles and the number of slots is reduced by adjusting the width W1 of the first through hole 61 . The cogging torque generated by the fluctuation of the magnetic force of the magnet 23 is reduced by adjusting the width W3 of the second through hole 62 . In addition, according to the stator core 11 using the stator core configuration sheet 11F, the first through holes 61 and the second through holes constituting the through hole group 6B can be formed in the same manner as the first slot 31 and the second slot 32 shown in FIG. 6 . Since the shape of 62 is a simple rectangle, it is easy to manufacture a mold and also to manufacture the stator core 11 . In addition, in the stator core configuration piece 11E shown in FIG. 8 , the number of through holes provided in the teeth 11a2 is three, whereas the number of through holes provided in the teeth 11a2 in the stator core configuration piece 11F shown in FIG. 9 is two. Therefore, the number of through holes can be reduced. Therefore, using the stator core 11 of the stator core configuration sheet 11F shown in FIG. 9 facilitates the manufacture of the stator core 11 .

FIG. 10 is a diagram showing a seventh modification of the stator core configuration sheet shown in FIG. 1 . In the teeth 11a2 of the stator core configuration piece 11G shown in FIG. 10 , a slot 3D and a through hole 6C are formed instead of the slot 3 shown in FIG. 3 . The groove 3D is formed at the center portion in the circumferential direction D2 of the distal end portion 11a21 in the inner peripheral portion 4 of the distal end portion 11a21. The through-hole 6C is formed in the center part in the circumferential direction D2 of the front-end|tip part 11a21. The through hole 6C is formed on the back yoke 11a1 side of the groove 3D in the radial direction D3.

The corner portion 5 is formed at the front end portion 11a21. The corner portion 5 is formed between the inner peripheral portion 4 of the front end portion 11a21 and the groove 3D.

Let the width from the end face on the back yoke 11a1 side of the through-hole 6C in the radial direction D3 to the corner 5 be W4, and the width from the mounting base 11a23 in the radial direction D3 to the first intersection IP1 be W5 , the width W4 is narrower than the width W5. The width W4 is equal to the maximum width from the corner portion 5 between the inner peripheral surface of the front end portion 11a21 and the groove 3D to the radially outer side of the through hole 6C. The width W5 is equal to the radial minimum thickness of the front end portion 11a21 from the inner peripheral portion 4 of the front end portion 11a21 to the boundary 11a22a of the front end portion 11a21 and the base portion 11a22. The first intersection IP1 is the intersection of the bisector CP10 and the virtual curve 11a4.

Let the width in the radial direction from the first intersection IP1 to the second intersection IP2 of the boundary 11a22a and the bisector CP10 be the first width (W5), and the width from the first intersection IP1 to the third intersection IP3 When the width in the radial direction is the second width (W4), the second width is narrower than the first width. The third intersection IP3 is the intersection between the radially outer end surface of the through hole 6C and the bisector CP10.

When the width in the circumferential direction D2 of the groove 3D is W1, the width in the circumferential direction D2 of the base portion 11a22 of the tooth 11a2 is W2, and the width in the circumferential direction D2 of the through hole 6C is W3, the width W1 Narrower than width W2 and wider than width W3.

According to the stator core 11 using the stator core configuration sheet 11G shown in FIG. 10 , by adjusting the width W1 of the slot 3D, the cogging torque generated by the combination of the number of magnetic poles and the number of slots is reduced, and the through hole 6C is adjusted to reduce the cogging torque. The width W3 of the permanent magnet 23 is adjusted so that the cogging torque due to the fluctuation of the magnetic force of the permanent magnet 23 is reduced. In addition, according to the stator core 11 using the stator core configuration sheet 11G, like the first slot 31 and the second slot 32 shown in FIG. is easy to manufacture, and in addition, the manufacture of the stator core 11 is easy. In addition, according to the stator core 11 using the stator core configuration sheet 11G, by increasing the width W1 of the slot 3D compared to the width W3 of the through hole 6C, the decrease in the gap magnetic flux density can be suppressed, and the decrease in torque can be minimized .

In addition, in FIG. 10, the example in the case where the width W1 of the groove 3D is wider than the width W3 of the through hole 6C has been described, but when the width W1 of the groove 3D is narrower than the width W3 of the through hole 6C, the get the same effect.

FIG. 11 is a diagram showing an eighth modification of the stator core configuration sheet shown in FIG. 1 . In the teeth 11a2 of the stator core configuration piece 11H shown in FIG. 11 , two slots 3E and through holes 6D are formed instead of the slots 3 shown in FIG. 3 . The two grooves 3E and the through hole 6D are formed at the center portion in the circumferential direction D2 of the distal end portion 11a21 in the inner peripheral portion 4 of the distal end portion 11a21. The through hole 6D is provided between the two grooves 3E, and the two grooves 3E and the through hole 6D are arranged in the order of the groove 3E, the through hole 6D, and the groove 3E in the circumferential direction D2.

A corner portion 5 is formed between the inner peripheral portion 4 of the front end portion 11a21 and the groove 3E. Let the width from the end face of the through hole 6D on the radial direction D3 on the back yoke 11a1 side to the corner 5 be W41, and the width from the bottom surface 3E1 of the groove 3E on the radial direction D3 to the corner 5 is set as W41 W42, when the width from the mounting base 11a23 in the radial direction D3 to the first intersection IP1 is W5, the width W41 is narrower than the width W5 and wider than the width W42. In addition, the width W42 is narrower than the width of the through hole 6D in the radial direction D3. The width W4 is equal to the maximum width from the corner portion 5 between the inner peripheral surface of the front end portion 11a21 and the groove 3E to the radially outer side of the through hole 6D. The width W5 is equal to the radial minimum thickness of the front end portion 11a21 from the inner peripheral portion 4 of the front end portion 11a21 to the boundary 11a22a of the front end portion 11a21 and the base portion 11a22. The first intersection IP1 is the intersection of the bisector CP10 and the inner peripheral surface of the tip portion 11a21.

Let the width in the radial direction from the first intersection IP1 to the second intersection IP2 of the boundary 11a22a and the bisector CP10 be the first width (W5), and the width from the first intersection IP1 to the third intersection IP3 When the width in the radial direction is the second width (W4), the second width is narrower than the first width. The third intersection IP3 is the intersection between the radially outer end surface of the through hole 6D and the bisector CP10.

Let the width from one end face of one groove 3E in the circumferential direction D2 to the other end face of the other groove 3E in the circumferential direction D2 be W1, and let the width of the groove 3E in the circumferential direction D2 be W11, and let When the width in the circumferential direction D2 of the base portion 11a22 of the tooth 11a2 is W2 and the width in the circumferential direction D2 of the through hole 6D is W3, the width W1 is narrower than the width W2, and the width W3 is narrower than the width W1 and equal to the width W11.

According to the stator core 11 using the stator core configuration sheet 11H shown in FIG. 11 , by adjusting the width W1 including the two slots 3E, the cogging torque due to the combination of the number of magnetic poles and the number of slots is reduced, By adjusting the width W3 of the through hole 6D, the cogging torque caused by the fluctuation of the magnetic force of the permanent magnet 23 is reduced. In addition, according to the stator core 11 using the stator core configuration sheet 11H, like the first slot 31 and the second slot 32 shown in FIG. is easy to manufacture, and in addition, the manufacture of the stator core 11 is easy. In addition, according to the stator core 11 using the stator core configuration sheet 11H, by providing the plurality of slots 3E, the cogging torque generated by the combination of the number of magnetic poles and the number of slots is further reduced.

Embodiment 2.

12 is a perspective view of a stator core according to Embodiment 2. FIG. The stator core 1A is composed of a plurality of stator core configuration pieces 11J instead of the plurality of stator core configuration pieces 11a shown in FIG. 1 . Slots 3 shown in FIG. 3 are formed at a plurality of locations at the tip end portions 11a21 of the teeth 11a2 of the stator core configuration piece 11J. The plurality of grooves 3 are arranged to be separated from each other in the axial direction D1. The stator core constituting sheet 11J is formed by alternately stacking a first steel plate group 7a composed of a plurality of thin plates having grooves 3 formed thereon and a second steel plate group 7b composed of a plurality of thin plates not forming the grooves in the axial direction D1. .

In the stator core 1A, the width in the circumferential direction D2 of each of the first slot 31 and the second slot 32 shown in FIG. 3 is adjusted so that the cogging torque generated in the first steel plate group 7a and the second The respective phases of the cogging torques generated in the steel plate group 7b are reversed. The phase and amplitude of the cogging torque generated by the combination of the number of magnetic poles and the number of slots are adjusted according to the width W1 of the first slot 31 , and the phase and amplitude of the cogging torque generated by the fluctuation of the magnetic force of the permanent magnet 23 are adjusted , and is adjusted according to the width W3 of the second groove 32 .

In addition, by adjusting the lamination thickness in the axial direction D1 of the first steel plate group 7a and the second steel plate group 7b, the amplitude of the cogging torque whose phase is reversed is adjusted in each tooth. The generated cogging torque is added to reduce the cogging torque of the entire stator. Further, by locally forming the grooves 3 in the distal end portion 11a21, compared with the case where the grooves 3 are formed over the entirety from one end to the other end in the axial direction D1 of the distal end portion 11a21, the following effects are obtained. The reduction of the gap magnetic flux density is suppressed, and the torque is improved.

In addition, in Embodiment 2, three grooves 3 are formed from one end to the other end of the distal end portion 11a21 in the axial direction D1, but the number of grooves 3 may be two or more, and is not limited to the illustrated example .

In the second embodiment, the example in which the grooves 3 are formed has been described, but instead of the grooves 3, the grooves shown in FIGS. 4 to 6 or the through holes shown in FIGS. The same effect is obtained also when two or more pieces are formed from one end to the other end of the front-end|tip part 11a21 in the direction D1.

In addition, the example in which the grooves 3 are formed in the second embodiment has been described, but instead of the grooves 3, a pair of the grooves and through holes shown in FIG. 10 or FIG. 11 may be formed at the front end portion 11a21 in the axial direction D1 The same effect is obtained also when two or more are formed from one end to the other end.

In addition, in Embodiments 1 and 2, the example in which the slots or through-holes are formed in the teeth provided in the stator core of the rotating electrical machine has been described, but the slots or through-holes described in Embodiments 1 and 2 are applied to linear motors The same effect will be obtained for the stator.

In addition, in Embodiments 1 and 2, the groove or the through hole is formed at the center portion in the circumferential direction D2 of the tooth tip portion, but the groove or the through hole is formed at a position close to the end portion in the circumferential direction D2 of the tooth tip portion In the case of a groove or a through hole, the same effect can be obtained if the groove or the through-hole has a shape in which the width in the circumferential direction D2 is gradually narrowed toward the outer or inner side in the radial direction D3.

In addition, in Embodiments 1 and 2, the grooves or through holes are formed symmetrically in the circumferential direction D2 with respect to the center portion in the circumferential direction D2 of the tooth tip portion, but if the grooves or through holes are formed in the circumferential direction D2 If the width is gradually narrowed toward the outside or inside of the radial direction D3, the same effect can be obtained even if it is asymmetric.

In addition, in Embodiments 1 and 2, a description has been given of the stator core formed by connecting a plurality of stator core constituent pieces in a ring shape, but instead of the stator core formed of a plurality of stator core constituent pieces, it is also possible to use Arbitrary of the stator core formed by lamination of sheets from the stator core punched out in the ring, the wrapped core connected to a part of the stator core, the wrapped core in which the stator core is partially superimposed, and the inner and outer split cores of the stator separated from the core seat and the teeth. Alternatively, the same effect can be obtained by forming a groove or a through hole having a shape in which the width in the circumferential direction D2 of the groove or through hole is gradually narrowed toward the outside or inside of the radial direction D3.

13 is a first diagram showing the relationship between the cogging torque generated in the rotors according to Embodiments 1 and 2 and the width of the slots. The vertical axis of FIG. 13 represents the cogging torque T1 due to the fluctuation of the magnetic force of the magnet, and the horizontal axis of FIG. 13 represents the width W3 of the second slot 32 shown in FIG. 14 is a second diagram showing the relationship between the cogging torque generated in the rotors according to Embodiments 1 and 2 and the width of the slots. The vertical axis of FIG. 14 represents the cogging torque T2 generated by the combination of the number of magnetic poles and the number of slots, and the horizontal axis of FIG. 14 sets the reference value to 1 and passes the width W1 of the first slot 31 shown in FIG. 3 and the like through Ratio representation.

By changing the width W3 of the second slot 32, the magnetic permeability distribution of the gap changes, and the amplitude and phase of the cogging torque generated by the magnetic permeability change. It can be seen that the inclination of the cogging torque in the region where the width W3 of the second groove 32 is smaller than 0.4 [p.u] is different from the inclination of the cogging torque in the region where the width W3 of the second groove 32 is larger than 0.4 [p.u]. In addition, it can be seen that the inclination of the cogging torque in the region where the width W1 of the first groove 31 is smaller than 0.4 [p.u] is different from the inclination of the cogging torque in the region where the width W1 of the first groove 31 is larger than 0.7 [p.u] of. In addition, it can be seen that the inclination of the cogging torque varies from 0.4 [p.u] to 0.7 [p.u] of the width W1 of the first groove 31 . In the stator core according to the present embodiment, the width of the slot or the through hole is set in consideration of the relationship between the cogging torque and the slot width as described above.

The configurations shown in the above embodiments represent an example of the contents of the present invention, and can be combined with other known technologies, and a part of the configurations can be omitted or changed without departing from the gist of the present invention.

Description of the label

1 Stator, 2 Rotor, 3, 3A, 3B, 3D, 3E Slots, 3B1, 3E1, 31a, 32a, 33a Bottom, 3C Slot Group, 4 Inner Circumference, 5, 51, 52 Corners, 6, 6C, 6D Through hole, 6A, 6B through hole group, 6a first area, 6b second area, 6c, 6d end face, 7a first steel plate group, 7b second steel plate group, 8 wires, 11 stator core, 11a, 11A, 11B, 11C, 11D, 11E, 11F, 11G, 11H, 11J stator core constituent pieces, 11a1 back yoke, 11a1a inner peripheral side, 11a22a boundary, 11a11 outer peripheral portion, 11a111 circumferential center, 11a2 teeth, 11a21 front end portion, 11a22 base portion, 11a23 Mounting Root, 11a3 Slot, 11a4 Imaginary Curve, 12 Winding, 21 Rotor Core, 22 Shaft, 23 Permanent Magnet, 24 Pole, 31 1st Slot, 32 2nd Slot, 33 3rd Slot, 41 Boss, 61 1st Slot Through hole, 62 second through hole, 100 rotating electrical machine, IP1 first intersection, IP2 second intersection, IP3 third intersection.

Claims (18)

1. A stator core constituting sheet comprising a plurality of stator core constituting sheets to constitute an annular stator core, The stator core constituent sheet is characterized in that: The stator core constituting piece is composed of a back yoke and teeth provided on the inner peripheral side of the back yoke, The teeth have a base portion extending in a central axis direction from a circumferential center of the back yoke, and a front end portion provided on an inner circumferential side of the base portion, A groove of a shape whose width in the circumferential direction changes stepwise toward the outer side in the radial direction of the stator core is formed on the inner peripheral portion of the front end portion, the width of the groove varies discontinuously, In the cross section perpendicular to the central axis direction, the width in the radial direction from the first intersection point to the second intersection point is the first width, the first intersection point being the following imaginary curve and the following bisector The imaginary curve is an imaginary curve extending the curve of the inner peripheral surface of the front end portion to the groove, and the bisector is the bisector that bisects the front end portion in the circumferential direction. bisector, the second intersection is the intersection between the bisector and the boundary between the base and the front end, When the width in the radial direction from the first intersection to the third intersection of the bottom surface of the groove and the bisector is the second width, The second width is narrower than the first width. 2 . The stator core constituent sheet according to claim 1 , wherein: 2 . The groove of the shape in which the width in the circumferential direction gradually narrows toward the outer side in the radial direction is formed by a first groove and a center portion in the circumferential direction of the first groove and formed in the groove. The second groove on the outer side in the radial direction of the first groove is constituted, The width of the first groove in the circumferential direction is wider than the width of the second groove in the circumferential direction. 3. The stator core forming sheet according to claim 2, characterized in that: The width of the first groove in the circumferential direction is wider than twice the width of the second groove in the circumferential direction. 4. The stator core constituent sheet according to any one of claims 1 to 3, characterized in that: The grooves are formed at eight or more corners, and the width in the circumferential direction changes stepwise toward the outer side in the radial direction of the stator core. 5. The stator core constituent sheet according to claim 1, characterized in that: In the front end portion, two or more of the grooves are formed from one end to the other end of the front end portion in the axial direction of the stator core. 6. A stator core forming sheet, comprising a plurality of stator core forming sheets to form an annular stator core, The stator core constituent sheet is characterized in that: The stator core constituting piece is composed of a back yoke and teeth provided on the inner peripheral side of the back yoke, The teeth have a base portion extending in a central axis direction from a circumferential center of the back yoke, and a front end portion provided on an inner circumferential side of the base portion, In the inner peripheral portion of the front end portion, there are formed a plurality of first grooves that are spaced apart and arranged in the circumferential direction, and a second groove provided between each of the plurality of the first grooves, The width of the second slot in the radial direction of the stator core is wider than the width of the first slot in the radial direction, In the cross section perpendicular to the central axis direction, the width in the radial direction from the first intersection point to the second intersection point is the first width, the first intersection point being the following imaginary curve and the following bisector The imaginary curve is an imaginary curve extending the curve of the inner peripheral surface of the front end portion to the groove, and the bisector is the bisector that bisects the front end portion in the circumferential direction. bisector, the second intersection is the intersection between the bisector and the boundary between the base and the front end, in the radial direction from the first intersection to the third intersection of the bottom surface of the second groove and the bisector from the inner peripheral portion of the front end portion toward the outer side in the radial direction When the width is set to the second width, The second width is narrower than the first width. 7. The stator core forming sheet according to claim 6, wherein In the front end portion, from one end to the other end of the front end portion in the axial direction of the stator core, two or more sets of the plurality of first slots and the second slots are formed. . 8. A stator core constituting sheet comprising a plurality of stator core constituting sheets to constitute an annular stator core, The stator core constituent sheet is characterized in that: The stator core constituting piece is composed of a back yoke and teeth provided on the inner peripheral side of the back yoke, The teeth have a base portion extending in a central axis direction from a circumferential center of the back yoke, and a front end portion provided on an inner circumferential side of the base portion, In the inner peripheral portion of the front end portion, a through hole having a shape whose width in the circumferential direction changes stepwise toward the outer side in the radial direction of the stator core is formed, From the first intersection point of the inner peripheral surface of the front end portion and the bisector that bisects the front end portion in the circumferential direction, to the base portion and the The width in the radial direction up to the boundary of the front end portion and the second intersection of the bisector is the first width, When the width in the radial direction from the first intersection to the radially outer end face of the through hole and the third intersection of the bisector is the second width, The second width is narrower than the first width. 9 . The stator core constituent sheet according to claim 8 , wherein: 10 . In the front end portion, two or more of the through holes are formed from one end to the other end of the front end portion in the axial direction of the stator core. 10. A stator core constituting sheet comprising a plurality of stator core constituting sheets constituting an annular stator core, The stator core constituent sheet is characterized in that: The stator core constituting piece is composed of a back yoke and teeth provided on the inner peripheral side of the back yoke, The teeth have a base portion extending in a central axis direction from a circumferential center of the back yoke, and a front end portion provided on an inner circumferential side of the base portion, In the inner peripheral portion of the front end portion, there are formed a plurality of first through holes spaced apart and arranged in the circumferential direction, and a second through hole provided between each of the plurality of the first through holes, The width of the second through hole in the radial direction of the stator core is wider than the width of the first through hole in the radial direction, From the first intersection point of the inner peripheral surface of the front end portion and the bisector that bisects the front end portion in the circumferential direction, to the base portion and the The width in the radial direction up to the boundary of the front end portion and the second intersection of the bisector is the first width, When the width in the radial direction from the first intersection to the radially outer end face of the second through hole and the third intersection of the bisector is the second width, The second width is narrower than the first width. 11. The stator core constituent sheet according to claim 10, characterized in that: In the front end portion, from one end to the other end of the front end portion in the axial direction of the stator core, a plurality of sets of the first through holes and the second through holes are formed to be greater than or equal to 2. 12. A stator core constituting sheet comprising a plurality of stator core constituting sheets constituting an annular stator core, The stator core constituent sheet is characterized in that: The stator core constituting piece is composed of a back yoke and teeth provided on the inner peripheral side of the back yoke, The teeth have a base portion extending in a central axis direction from a circumferential center of the back yoke, and a front end portion provided on an inner circumferential side of the base portion, A first through hole and a second through hole provided between the first through hole and the back yoke are formed in the inner peripheral portion of the front end portion, The width in the circumferential direction of the second through hole is narrower than the width in the circumferential direction of the first through hole, From the first intersection point of the inner peripheral surface of the front end portion and the bisector that bisects the front end portion in the circumferential direction, to the base portion and the The width in the radial direction up to the boundary of the front end portion and the second intersection of the bisector is the first width, When the width in the radial direction from the first intersection to the radially outer end face of the second through hole and the third intersection of the bisector is the second width, The second width is narrower than the first width. 13. The stator core forming sheet according to claim 12, characterized in that: In the front end portion, two or more sets of the first through hole and the second through hole are formed from one end to the other end of the front end portion in the axial direction of the stator core. . 14. A stator core forming sheet comprising a plurality of stator core forming sheets to form an annular stator core, The stator core constituent sheet is characterized in that: The stator core constituting piece is composed of a back yoke and teeth provided on the inner peripheral side of the back yoke, The teeth have a base portion extending in a central axis direction from a circumferential center of the back yoke, and a front end portion provided on an inner circumferential side of the base portion, A groove is formed in the inner peripheral portion of the front end portion, and a through hole provided between the groove and the back yoke is formed separately from the groove, The width in the circumferential direction of the groove is wider than the width in the circumferential direction of the through hole, or narrower than the width in the circumferential direction of the through hole, In the cross section perpendicular to the central axis direction, the width in the radial direction from the first intersection point to the second intersection point is the first width, the first intersection point being the following imaginary curve and the following bisector The imaginary curve is an imaginary curve extending the curve of the inner peripheral surface of the front end portion to the groove, and the bisector is the bisector that bisects the front end portion in the circumferential direction. bisector, the second intersection is the intersection between the bisector and the boundary between the base and the front end, When the width in the radial direction from the first intersection to the radially outer end face of the through hole and the third intersection of the bisector is the second width, The second width is narrower than the first width. 15. The stator core forming sheet according to claim 14, characterized in that: In the front end portion, two or more sets of the grooves and the through holes are formed from one end to the other end of the front end portion in the axial direction of the stator core. 16. A stator core forming sheet comprising a plurality of stator core forming sheets to form an annular stator core, The stator core constituent sheet is characterized in that: The stator core constituting piece is composed of a back yoke and teeth provided on the inner peripheral side of the back yoke, The teeth have a base portion extending in a central axis direction from a circumferential center of the back yoke, and a front end portion provided on an inner circumferential side of the base portion, In the inner peripheral portion of the front end portion, a plurality of grooves are formed which are spaced apart and arranged in the circumferential direction, and through holes provided between each of the plurality of the grooves are formed, From the first intersection point of the inner peripheral surface of the front end portion and the bisector that bisects the front end portion in the circumferential direction, to the base portion and the The width in the radial direction up to the boundary of the front end portion and the second intersection of the bisector is the first width, When the width in the radial direction from the first intersection to the radially outer end face of the through hole and the third intersection of the bisector is the second width, The second width is narrower than the first width. 17. The stator core forming sheet according to claim 16, characterized in that: In the front end portion, two or more sets of the grooves and the through holes are formed from one end to the other end of the front end portion in the axial direction of the stator core. 18 . A rotating electrical machine comprising a stator core formed by connecting a plurality of stator core forming sheets according to claim 1 in a ring shape. 19 .

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