JP2022142154A - Stator and rotary electric machine - Google Patents

Abstract

To provide a stator capable of suppressing an iron loss and a torque ripple of the stator, and a rotary electric machine.SOLUTION: A stator comprises: a stator core including a plurality of teeth 110 forming a slot 11S; a coil 12 disposed in the slot 11S; and a magnetic wedge 13 provided between the coil 12 and a rotor 20. The magnetic wedge 13 comprises a projection 131 including an opposite face 13A opposed to the rotor 20 and a side face 13B continued to the opposite face 13A and extending away from the rotor 20. The side face 13B and the teeth 110 are separated.SELECTED DRAWING: Figure 2

Description

The present invention relates to stators and rotating electric machines.

2. Description of the Related Art Conventionally, in a stator, there has been a rotating electric machine in which a magnetic wedge is provided on the rotor side of a coil sandwiched between teeth (see, for example, Patent Document 1).

Japanese Patent Application Laid-Open No. 2002-281709

However, in the rotating electric machine disclosed in Patent Document 1, the influence of the magnetic wedge sometimes worsens the iron loss of the stator and fluctuates the magnetic flux of the stator.

An object of the present invention is to provide a stator and a rotating electric machine that can suppress iron loss and torque ripple of the stator.

In order to solve the above problems, the present invention proposes the following means.
(1) A stator according to the present invention (for example, the stator 10 of the embodiment) is a stator core (for example, a stator core ( For example, the stator core 11 of the embodiment), the winding arranged in the slot (for example, the winding 12 of the embodiment), and the winding provided between the winding and the rotor (for example, the rotor 20 of the embodiment). and a magnetic wedge (for example, the magnetic wedge 13 of the embodiment), the magnetic wedge has a facing surface facing the rotor (for example, the facing surface 13A of the embodiment) and a and a projection (eg, projection 131 in the embodiment) having a side surface (eg, side surface 13B in the embodiment) extending away from the rotor, and the side surface and the tooth are spaced apart.

According to this configuration, the side surface and the tooth portion are spaced apart. Therefore, the change in distribution of the magnetic flux density in the circumferential direction in the vicinity of the inner surface of the stator can be smoothed. Thereby, iron loss and torque ripple of the stator can be suppressed.

(2) In a cross section perpendicular to the rotation axis of the rotor (for example, the rotation axis P in the embodiment), the width of the facing surface (for example, the width X in the embodiment) is the innermost surface of the winding (for example, the rotation axis P in the embodiment). innermost surface 12A) (eg width Y in the embodiment) or less.

According to this configuration, the width of the facing surface is made equal to or less than the width of the innermost surface of the winding. Therefore, it is possible to reduce iron loss and reduce torque ripple without significantly affecting the torque, which is the main performance of the rotary electric machine.

(3) The width of the facing surface may be 50% or more of the width of the innermost surface of the winding.

According to this configuration, the width of the facing surface is 50% or more of the width of the innermost surface of the winding. Therefore, it is possible to significantly reduce iron loss and torque ripple without significantly affecting the torque, which is the main performance of the rotary electric machine.

(4) The facing surface may be positioned along an extension surface of the inner surface of the stator (for example, extension surface M in the embodiment).

According to this configuration, the facing surface is positioned along the extended surface of the inner surface of the stator. As a result, the facing surfaces of the magnetic wedges can be accurately arranged along the extended surface of the inner surface of the stator. Therefore, it is possible to suppress the change in the magnetic flux density in the circumferential direction near the inner surface of the stator.

(5) The magnetic wedge may have a magnetic powder content of 30% or more and 80% or less.

According to this configuration, the magnetic wedge had a magnetic powder content of 30% or more and 80% or less. As a result, it is possible to significantly reduce iron loss and torque ripple while maintaining torque.

(6) The magnetic wedge may include an insulating foam material (eg, the foam material 133 of the embodiment) that covers the outer surface of the magnetic wedge (eg, the outer surface 13D of the embodiment).

According to this configuration, the magnetic wedge includes an insulating foam material covering the outer surface of the magnetic wedge. Thereby, the insulation between the magnetic wedge and the winding can be enhanced.

(7) The tooth portion has a groove (for example, the groove 112 in the embodiment) along the rotation axis of the rotor, and the magnetic wedge has the foam material on its outer surface (for example, the flange in the embodiment). 132), and the collar may fit into the groove.

According to this configuration, the tooth portion had a groove along the rotation axis of the rotor. As a result, the magnetic wedge can be reliably positioned and fixed with respect to the teeth. Further, the magnetic wedge has a flange portion (for example, the flange portion 132 of the embodiment) having the foam material on its outer surface, and the flange portion is fitted in the groove. As a result, the pressure of the foam material can be used to reliably fit the flange of the magnetic wedge into the groove of the tooth.

(8) The magnetic wedge and the winding may be separated by an air gap.

According to this configuration, the magnetic wedge and the winding are spaced apart through the air gap. Thereby, the insulation between the magnetic wedge and the winding can be enhanced.

(9) The magnetic wedge may have, on its outer surface, a recessed portion (for example, the recessed portion 134 in the embodiment) that is recessed in the direction toward the rotor.

According to this configuration, the magnetic wedge has a recess on the outer surface that is recessed in the direction toward the rotor. As a result, it is possible to suppress a decrease in torque due to short-circuiting of the magnetic flux loop.

(10) A rotating electrical machine according to the present invention (for example, rotating electrical machine 1 of the embodiment) may include the stator.

According to this configuration, the rotating electrical machine includes the stator. Thereby, iron loss and torque ripple of the stator can be suppressed.

ADVANTAGE OF THE INVENTION According to this invention, the stator and rotary electric machine which can suppress the iron loss and torque ripple of a stator can be provided.

1 is a cross-sectional view of a rotating electric machine according to an embodiment; FIG. FIG. 2 is a detailed view of part A in FIG. 1; FIG. 4 is a diagram showing the relationship between cases (1) to (4) in which the relationship between the width of the facing surface of the convex portion of the magnetic wedge and the width of the innermost surface of the winding is different, and the relationship between iron loss, torque, and torque ripple. . FIG. 4 is a comparison diagram showing iron loss distribution and magnetic flux density distribution for case (1), case (3) and case (4).

A stator 10 according to an embodiment of the present invention and a rotary electric machine 1 including the stator 10 will be described below with reference to the drawings. The direction perpendicular to the rotation axis P of the rotor 20 is sometimes called the radial direction, and the direction in which a circle is formed around the rotation axis P of the rotor 20 is sometimes called the circumferential direction. In addition, the direction away from the rotation axis P may be referred to as the outward direction, and the direction toward the rotation axis P may be referred to as the inner direction. In addition, an outer surface may be called an outer surface, and an inner surface may be called an inner surface.

<Rotating electric machine>
FIG. 1 is a cross-sectional view of a rotating electrical machine 1 according to this embodiment. FIG. 2 is a detailed view of part A in FIG. Note that the cross section of the rotating electrical machine 1 is generally rotationally symmetrical according to the number of poles of the rotor, so only a portion thereof is illustrated in FIG. 1 and the other portions are omitted.
As shown in FIG. 1 or FIG. 2 , the rotary electric machine 1 includes a rotor 20 that rotates about a rotation axis P, and a stator 10 that annularly covers the rotor 20 about the rotation axis P. As shown in FIG. The rotary electric machine 1 is, for example, a synchronous motor. The rotating electrical machine 1 includes, for example, a rotor 20 with eight poles, and a stator 10 having 48 slots 11S containing windings 12 .

<Rotor>
The rotor 20 is a cylindrical structure that rotates around the rotation axis P. As shown in FIG. The rotor 20 has magnets with different poles alternately arranged in the circumferential direction. The rotor 20 includes, for example, permanent magnets. The rotor 20 has eight poles, for example.

<Stator>
The stator 10 includes a stator core 11 having a plurality of teeth 110 forming slots 11S, windings 12 arranged in the slots 11S, and magnetic wedges 13 provided between the windings 12 and the rotor 20. I have.
The magnetic wedge 13 includes a convex portion 131 having a facing surface 13A facing the rotor 20 and a side surface 13B extending in a direction away from the rotor 20 following the facing surface 13A.
Here, the side surface 13B and the tooth portion 110 are separated. Thus, since the side surface 13B of the protrusion 131 of the magnetic wedge 13 and the toothed portion 110 are separated from each other, magnetic flux can be prevented from concentrating in the vicinity of the inner surface of the toothed portion 110 . Therefore, the change in the magnetic flux density generated from the vicinity of the inner surface of the tooth portion 110 to the vicinity of the inner surface of the magnetic wedge 13 can be smoothed, and the magnetic flux density in the vicinity of the inner surface of the stator 10 can be made uniform in the circumferential direction. Therefore, torque ripple due to iron loss and magnetic flux fluctuation of the stator 10 can be suppressed.

<Stator core>
The stator core 11 is formed by laminating electromagnetic steel sheets, for example. The stator core 11 has a cylindrical shape with a cavity in the center that accommodates the rotor 20 . Stator core 11 has a plurality of teeth 110 extending from the outer peripheral portion toward rotation axis P of rotor 20 . The cross section of the tooth portion 110 is uniform along the rotation axis P in the cross section perpendicular to the rotation axis P of the rotor 20 .
The stator core 11 has teeth 110 and slots 11S alternately arranged along the circumferential direction of the stator 10 . The stator core 11 has, for example, 48 teeth 110 and 48 slots 11S.

The teeth 110 may have grooves 112 along the axis of rotation P of the rotor 20 . The groove 112 is provided so as to open to the slot 11S. Both ends of the magnetic wedge 13 are fitted and fixed in the grooves 112 . If the magnetic wedge 13 has a flange 132 having a foam material 133 described later on the outer surface 13D, the flange 132 fits into the groove 112 . That is, the groove 112 may be fitted with a collar portion 132 having a foam material 133 on the outer surface 13D. When the foam material 133 is applied to at least the outer surface 13D of the flange part 132 of the magnetic wedge 13, the flange part 132 is inserted into the groove 112 of the tooth part 110, and the foam material 133 is heated, the foam material 133 foams and expands. Then, a force is generated that presses the flange 132 inward. Then, the magnetic wedge 13 is securely fixed by fitting into the groove 112 with its radial position determined.

<Winding>
Winding 12 is arranged to pass through slot 11S. The winding 12 is, for example, a rectangular wire made of copper. When the winding 12 is a rectangular wire, the winding 12 is arranged such that the short side of the cross section of the rectangular wire is along the radial direction away from the rotation axis P, and the long side is along the circumferential direction, and the slot 11S is closed. Inside, they are radially stacked and bundled.
An insulating sheet is interposed between the winding 12 and the wall surface 111 of the tooth portion 110, and filled with an insulating material such as varnish.

<Magnetic wedge>
The magnetic wedges 13 are provided between the windings 12 and the rotor 20 to prevent the windings 12 from falling out of the slots 11S and to adjust the distribution of the magnetic flux density in the circumferential direction near the inner surface of the stator 10. is provided. The magnetic wedge 13 is a rod-shaped body extending along the rotation axis P. As shown in FIG. The magnetic wedge 13 is bridged between adjacent tooth portions 110 so as to block the inside of the slot 11S.
The magnetic wedge 13 is made of a magnetic material containing magnetic powder such as iron powder. The magnetic wedge 13 may be manufactured, for example, by injection molding a resin containing magnetic powder. Magnetic wedge 13 may be, for example, an amorphous metal.

The magnetic wedge 13 preferably has a magnetic powder content of 30% or more and 80% or less. Note that the magnetic powder content rate is the ratio of the volume of the magnetic powder to the volume of the entire components constituting the magnetic wedge 13 excluding the foam material 133 . As a result, it is possible to significantly reduce iron loss and torque ripple while maintaining torque.

The magnetic wedge 13 has a hat-shaped cross section, as shown in FIG. Specifically, the magnetic wedge 13 includes a convex portion 131 having a facing surface 13A facing the rotor 20 and a side surface 13B extending in a direction away from the rotor 20 following the facing surface 13A. Since the magnetic wedge 13 has the convex portion 131 , a gap can be formed between the magnetic wedge 13 and the tooth portion 110 . Therefore, the transmission of magnetic flux from the vicinity of the inner surface 113 of the tooth portion 110 to the vicinity of the facing surface 13A of the magnetic wedge 13 can be suppressed. Therefore, the distribution of the magnetic flux density in the circumferential direction near the inner surface of the stator 10 can be made uniform.

The facing surface 13A is positioned along the extended surface M of the inner surface 113 of the stator 10. As shown in FIG. As a result, the magnetic wedge 13 is fixed to the teeth 110 with the inner surface of the flange 132 in contact with the inner surface of the groove 112 of the teeth 110 . It can be precisely arranged along M. Therefore, changes in the magnetic flux density in the circumferential direction near the inner surface of the stator 10 can be suppressed.

The magnetic wedge 13 has a collar portion 132 that fits on the wall surface 111 of the tooth portion 110 . The magnetic wedge 13 may fit into a groove 112 provided in the wall surface 111 of the tooth portion 110 .

The magnetic wedge 13 has a recess 134 recessed in the direction toward the rotor 20 on the outer surface 13D. Thereby, a gap can be formed in the concave portion 134 . Then, it is possible to shift the position in the radial direction between the portion where the magnetic wedge 13 and the tooth portion 110 are in contact (for example, the portion where the collar portion 132 and the groove 112 are in contact) and the gap therebetween. Therefore, magnetic flux can be made difficult to be transmitted from one of the adjacent tooth portions 110 to the other of the adjacent tooth portions 110 via the magnetic wedge 13 . Therefore, it is possible to suppress a decrease in torque due to short-circuiting of the magnetic flux loop.

The magnetic wedge 13 may include a foam material 133 that covers the outer surface 13D of the magnetic wedge 13 and has insulating properties. The foam material 133 may be one that foams and expands when heated, or one that foams and expands over time. The foam material 133 may be liquid paint or may be in the form of a sheet that can be applied to the outer surface 13D of the magnetic wedge 13 . Thereby, the insulation between the magnetic wedge 13 and the winding 12 can be improved. Further, when the outer surface 13D of the flange portion 132 of the magnetic wedge 13 is provided with the foam material 133 and is inserted into the groove 112 of the tooth portion 110, the expansion of the foam material 133 causes the magnetic wedge 13 to move against the groove 112. It can be fixed in a securely fitted state.

Magnetic wedge 13 and winding 12 are preferably separated by an air gap. Thereby, the insulation between the magnetic wedge 13 and the winding 12 can be improved.

Between the flange portion 132 of the magnetic wedge 13 and the groove 112, there may be a gap e in the circumferential direction. Further, the gap e may be filled with a foam material 133 . As a result, it is possible to improve the insulating property and reduce the area where the magnetic flux is short-circuited from the tooth portion 110 to the magnetic wedge 13 . Therefore, the distribution of the magnetic flux density in the circumferential direction near the inner surface 113 of the stator 10 can be appropriately leveled.

(Relationship between convex portion of magnetic wedge and width of winding)
Next, the relationship between the width X of the facing surface 13A of the protrusion 131 of the magnetic wedge 13 and the width Y of the winding 12 will be described.
FIG. 3 shows cases (1) to (4) in which the relationship between the width X of the facing surface 13A of the convex portion 131 of the magnetic wedge 13 and the width Y of the innermost surface 12A of the winding 12 is different, iron loss, It is a figure showing the relationship between a torque and a torque ripple.
As shown in FIG. 3, using a common rotor 20, numerical analysis and experiments were conducted to measure iron loss, torque, and torque ripple for cases (1) to (4) in which the structure of the stator 10 was changed. rice field. In each case, the magnetic powder content of the magnetic wedge 13 was varied.
Case (1) is a case in which the width X of the facing surface 13A of the protrusion 131 of the magnetic wedge 13 is less than 50% of the width Y of the innermost surface 12A of the winding 12 .
Case (2) is a case in which the width X of the facing surface 13A of the protrusion 131 of the magnetic wedge 13 is 50% or more and less than 90% of the width Y of the innermost surface 12A of the winding 12 .
Case (3) is a case in which the width X of the facing surface 13A of the convex portion 131 of the magnetic wedge 13 is set to 90% or more and 100% or less of the width Y of the innermost surface 12A of the winding 12 .
Case (4) is a case in which the width X of the facing surface 13A of the convex portion 131 of the magnetic wedge 13 is set to more than 100% of the width Y of the innermost surface 12A of the winding 12 .
As a result of numerical analysis and experiments, as shown in FIG. % range, it was confirmed that iron loss and torque ripple could be reduced remarkably while maintaining torque.

Also, the results of numerical analysis were compared with respect to the respective distributions of iron loss and magnetic flux density in the cross sections of the stator core 11 and rotor 20 .
FIG. 4 is a comparative diagram showing iron loss distribution and magnetic flux density distribution for case (1), case (3) and case (4).
As shown in FIG. 4, it was confirmed that the iron loss of the rotor 20, especially the iron loss in the vicinity of the outer surface of the rotor 20, can be reduced in the case (3) compared to the case (1). It was also confirmed that case (3) can reduce the iron loss of stator core 11, particularly the iron loss near the inner surface of tooth portion 110 of stator core 11, compared to case (4).
It was also confirmed that case (3) can reduce the magnetic flux fluctuation of the rotor 20 compared to case (1). In addition, it was confirmed that case (3) alleviated the concentration of magnetic flux, particularly at the connecting portion between tooth 110 and magnetic wedge 13 of stator core 11, and reduced magnetic flux fluctuation, compared to case (4).

In a cross section perpendicular to the rotation axis P of the rotor 20, that is, as shown in FIGS. Preferably (case (1), case (2) and case (3)): The innermost surface 12A is the inner surface of the windings 12 that is closest to the rotation axis P and closest to the rotor 20. means the inner surface of the winding 12 at . The width Y of the innermost surface 12A means the maximum dimension in the circumferential direction of the innermost winding 12. If the winding 12 is a flat wire as shown in the figure, the width Y of the flat wire in cross section is It means the dimension of the side (long side) along the direction. By setting the relationship between the width X of the facing surface 13A of the convex portion 131 of the magnetic wedge 13 and the width Y of the innermost surface 12A of the winding 12, as shown in FIG. It is possible to reduce iron loss and reduce torque ripple without significantly affecting torque.

In a cross section perpendicular to the rotation axis P of the rotor 20, that is, as shown in FIGS. More preferably, it is 50% or more of the width Y (case (2) and case (3)). By setting the relationship between the width X of the facing surface 13A of the convex portion 131 of the magnetic wedge 13 and the width Y of the innermost surface 12A of the winding 12, as shown in FIG. Iron loss can be greatly reduced and torque ripple can be reduced without significantly affecting torque.

The technical scope of the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the scope of the present invention.

In addition, it is possible to appropriately replace the constituent elements in the above-described embodiment with well-known constituent elements without departing from the spirit of the present invention, and the modifications described above may be combined as appropriate.

1 Rotating electric machine 10 Stator 11 Stator core 11S Slot 12 Winding 12A Innermost surface 13 Magnetic wedge 13A Opposed surface 13B Side surface 13D Outer surface 20 Rotor 110 Toothed portion 111 Wall surface 112 Groove 113 Inner surface 131 Convex portion 132 Collar portion 133 Foam material 134 Concave portion M Extended surface P Axis of rotation X Width Y (of facing surface) Width (of innermost surface)

Claims (10)

a stator core having a plurality of teeth forming slots;
a winding arranged in the slot;
and a magnetic wedge provided between the winding and the rotor,
The magnetic wedge has a convex portion that has a facing surface that faces the rotor and a side surface that follows the facing surface and extends in a direction away from the rotor,
A stator, wherein the side surface and the tooth portion are separated from each other. 2. The stator according to claim 1, wherein the width of the facing surface is equal to or less than the width of the innermost surface of the winding in a cross section perpendicular to the rotating shaft of the rotor. 3. The stator according to claim 2, wherein the width of said facing surface is 50% or more of the width of the innermost surface of said winding. 4. The stator according to any one of claims 1 to 3, wherein the facing surface is positioned along an extension surface of the inner surface of the stator. 5. The stator according to any one of claims 1 to 4, wherein the magnetic wedge has a magnetic powder content of 30% or more and 80% or less. 6. The stator according to any one of claims 1 to 5, wherein the magnetic wedge includes a foam material covering an outer surface of the magnetic wedge and having insulating properties. the tooth portion has a groove along the rotation axis of the rotor;
The magnetic wedge includes a collar portion having the foam material on its outer surface,
7. The stator according to claim 6, wherein said flange is fitted in said groove. 8. The stator according to any one of claims 1 to 7, wherein the magnetic wedge and the winding are separated by an air gap. 9. The stator according to any one of claims 1 to 8, wherein the magnetic wedge has, on its outer surface, a recess recessed in a direction toward the rotor. A rotary electric machine comprising the stator according to any one of claims 1 to 9.

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