Stator and rotating electric machine

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

[Technical field]

[0001] The present invention relates to a stator and a rotating electric machine. [Background technology]

[0002] Conventionally, there has been a rotating electric machine in which a stator is provided with a magnetic wedge on the rotor side of a coil sandwiched between teeth (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2002-281709 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the rotating electric machine described in Patent Document 1, the influence of the magnetic wedge can cause the iron loss of the stator to increase and the magnetic flux of the stator to fluctuate.

[0005] An object of the present invention is to provide a stator and a rotating electric machine capable of suppressing iron loss and torque ripple in the stator. [Means for solving the problem]

[0006] In order to solve the above problems, the present invention proposes the following means. (1) A stator according to the present invention (e.g., stator 10 of the embodiment) includes a stator core (e.g., stator core 11 of the embodiment) having a plurality of teeth (e.g., tooth portion 110 of the embodiment) forming a slot (e.g., slot 11S of the embodiment), a winding (e.g., winding 12 of the embodiment) arranged in the slot, and a magnetic wedge (e.g., magnetic wedge 13 of the embodiment) provided between the winding and a rotor (e.g., rotor 20 of the embodiment), in which the magnetic wedge includes a protrusion (e.g., protrusion 131 of the embodiment) having an opposing surface (e.g., opposing surface 13A of the embodiment) facing the rotor and a side surface (e.g., side surface 13B of the embodiment) extending in a direction away from the rotor subsequent to the opposing surface, and the side surface and the teeth are spaced apart.

[0007] According to this configuration, the side surface and the teeth are spaced apart, which makes it possible to smooth the change in the circumferential distribution of magnetic flux density in the vicinity of the inner surface of the stator, thereby suppressing iron loss and torque ripple in the stator.

[0008] (2) In a cross section perpendicular to the rotation axis of the rotor (e.g., rotation axis P in the embodiment), the width of the opposing surface (e.g., width X in the embodiment) may be equal to or smaller than the width (e.g., width Y in the embodiment) of the innermost surface of the winding (e.g., innermost surface 12A in the embodiment).

[0009] According to this configuration, the width of the opposing surface is equal to or smaller than the width of the innermost surface of the winding, which makes it possible to reduce iron loss and torque ripple without significantly affecting torque, which is the main performance of a rotating electric machine.

[0010] (3) The width of the opposing surface may be 50% or more of the width of the innermost surface of the winding.

[0011] According to this configuration, the width of the opposing surface is 50% or more of the width of the innermost surface of the winding, which makes it possible to significantly reduce iron loss and torque ripple without significantly affecting torque, which is the main performance of a rotating electric machine.

[0012] (4) The opposing surface may be located along an extension surface of the inner surface of the stator (for example, extension surface M in the embodiment).

[0013] According to this configuration, the opposing surface is positioned along the extension surface of the inner surface of the stator, so that the opposing surface of the magnetic wedge can be precisely positioned along the extension surface of the inner surface of the stator, thereby suppressing the change in magnetic flux density in the circumferential direction near the inner surface of the stator.

[0014] (5) The magnetic wedge may have a magnetic powder content of 30% or more and 80% or less.

[0015] According to this configuration, the magnetic wedge has a magnetic powder content of 30% or more and 80% or less, which significantly reduces iron loss and torque ripple while maintaining torque.

[0016] (6) The magnetic wedge may include an insulating foam material (for example, foam material 133 in the embodiment) covering an outer surface of the magnetic wedge (for example, outer surface 13D in the embodiment).

[0017] According to this configuration, the magnetic wedge includes an insulating foam material that covers the outer surface of the magnetic wedge, thereby improving the insulation between the magnetic wedge and the winding.

[0018] (7) The tooth portion may have a groove (e.g., groove 112 in the embodiment) that runs along the rotation axis of the rotor, and the magnetic wedge may have a flange portion (e.g., flange portion 132 in the embodiment) that has the foam material on its outer surface, and the flange portion may be fitted into the groove.

[0019] According to this configuration, the tooth portion has a groove that is aligned with the rotation axis of the rotor. This allows the magnetic wedge to be reliably positioned and fixed relative to the tooth portion. The magnetic wedge also includes a flange portion (e.g., flange portion 132 in the embodiment) having the foam material on its outer surface, and the flange portion is fitted into the groove. This allows the flange portion of the magnetic wedge to be reliably fitted into the groove of the tooth portion by utilizing the pressure of the foam material.

[0020] (8) The magnetic wedge and the winding may be spaced apart via an air gap.

[0021] According to this configuration, the magnetic wedge and the winding are separated by a gap, which can improve the insulation between the magnetic wedge and the winding.

[0022] (9) The magnetic wedge may have a recess (for example, recess 134 in the embodiment) on its outer surface that is recessed in a direction toward the rotor.

[0023] According to this configuration, the magnetic wedge has an outer surface provided with a recess that is recessed in a direction toward the rotor, thereby making it possible to suppress a decrease in torque caused by a short circuit of the magnetic flux loop.

[0024] (10) A rotating electric machine according to the present invention (for example, the rotating electric machine 1 of the embodiment) may include the stator described above.

[0025] According to this configuration, a rotating electric machine includes the stator, whereby iron loss and torque ripple of the stator can be suppressed. Effect of the Invention

[0026] According to the present invention, it is possible to provide a stator and a rotating electric machine capable of suppressing iron loss and torque ripple in the stator. [Brief description of the drawings]

[0027] [Figure 1] 1 is a cross-sectional view of a rotating electric machine according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a detailed view of part A in FIG. [Diagram 3] FIG. 13 is a diagram showing the relationship between iron loss, torque, and torque ripple for cases (1) to (4) in which the relationship between the width of the opposing surface of the protruding portion of the magnetic wedge and the width of the innermost surface of the winding is different. [Figure 4] FIG. 1 is a comparative diagram showing iron loss distribution and magnetic flux density distribution for cases (1), (3), and (4). DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0028] Hereinafter, a stator 10 according to an embodiment of the present invention and a rotating electric machine 1 including the stator 10 will be described with reference to the drawings. Note that a direction perpendicular to the rotation axis P of the rotor 20 is sometimes referred to as a radial direction, and a direction that draws a circle centered on the rotation axis P of the rotor 20 is sometimes referred to as a circumferential direction. Note that a direction away from the rotation axis P is sometimes referred to as an outward direction, and a direction toward the rotation axis P is sometimes referred to as an inward direction. Note that an outer surface is sometimes referred to as an outer surface, and an inner surface is sometimes referred to as an inner surface.

[0029] <Rotary Electric Machines> Fig. 1 is a cross-sectional view of a rotating electric machine 1 according to this embodiment. Fig. 2 is a detailed view of part A in Fig. 1. Note that since the cross section of the rotating electric machine 1 is generally rotationally symmetrical according to the number of poles of the rotor, only a portion of it is shown in Fig. 1, and the other portions are not shown. 1 or 2, the rotating electric machine 1 includes a rotor 20 that rotates about a rotation axis P, and a stator 10 that covers the rotor 20 in an annular shape about the rotation axis P. The rotating electric machine 1 is, for example, a synchronous motor. The rotating electric machine 1 includes, for example, an 8-pole rotor 20, and a stator 10 that has 48 slots 11S that house windings 12.

[0030] <Rotor> The rotor 20 is a cylindrical structure that rotates about a rotation axis P. The rotor 20 has magnets with different poles arranged alternately in the circumferential direction. The rotor 20 includes, for example, a permanent magnet. The number of poles of the rotor 20 is, for example, eight.

[0031] <Stator> The stator 10 includes a stator core 11 having a plurality of teeth 110 forming slots 11S, a winding 12 arranged in the slots 11S, and a magnetic wedge 13 provided between the winding 12 and the rotor 20. The magnetic wedge 13 includes a protrusion 131 having a facing surface 13A facing the rotor 20 and a side surface 13B extending in a direction away from the rotor 20 from the facing surface 13A. Here, the side surface 13B is spaced apart from the tooth portion 110. In this manner, since the side surface 13B of the protrusion 131 of the magnetic wedge 13 is spaced apart from the tooth portion 110, it is possible to prevent magnetic flux from concentrating near the inner surface of the tooth portion 110. Therefore, it is possible to make the change in magnetic flux density occurring between the vicinity of the inner surface of the tooth portion 110 and the vicinity of the inner surface of the magnetic wedge 13 gentle, and it is possible to make the magnetic flux density near the inner surface of the stator 10 uniform in the circumferential direction. Therefore, it is possible to suppress the iron loss of the stator 10 and the torque ripple due to magnetic flux fluctuation.

[0032] <Stator core> The stator core 11 is formed, for example, by laminating electromagnetic steel sheets. The stator core 11 is cylindrical with a cavity in the center for accommodating the rotor 20. The stator core 11 has a plurality of teeth 110 extending from the outer periphery toward the rotation axis P of the rotor 20. In a cross section perpendicular to the rotation axis P of the rotor 20, the cross section of the teeth 110 is uniform along the rotation axis P. The stator core 11 has teeth 110 and slots 11S arranged alternately along the circumferential direction of the stator 10. The stator core 11 has, for example, 48 teeth 110 and 48 slots 11S.

[0033] The tooth portion 110 may have a groove 112 along the rotation axis 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 groove 112. When the magnetic wedge 13 has a flange portion 132 having a foam material 133 described later on its outer surface 13D, the flange portion 132 is fitted in the groove 112. That is, the flange portion 132 having the foam material 133 on its outer surface 13D may be fitted in the groove 112. In a state where the foam material 133 is applied to at least the outer surface 13D of the flange portion 132 of the magnetic wedge 13, the flange portion 132 is inserted into the groove 112 of the tooth portion 110, and the foam material 133 is heated, the foam material 133 foams and expands, generating a force that presses the flange portion 132 inward. Then, the magnetic wedge 13 is fitted into the groove 112 with its radial position determined, and is securely fixed therein.

[0034] <Winding> The winding 12 is arranged to pass through the slot 11S. The winding 12 is, for example, a rectangular copper wire. When the winding 12 is a rectangular wire, the winding 12 is bundled in the slot 11S in a radially overlapping manner with the short side of the cross section of the rectangular wire aligned in the radial direction away from the rotation axis P and the long side aligned in the circumferential direction. An insulating sheet is interposed between the winding 12 and the wall surface 111 of the tooth portion 110, and is filled with an insulating material such as varnish.

[0035] <Magnetic wedge> The magnetic wedge 13 is provided between the winding 12 and the rotor 20 in order to prevent the winding 12 from falling out of the slot 11S and to adjust the circumferential distribution of the magnetic flux density near the inner surface of the stator 10. The magnetic wedge 13 is a rod-shaped body extending along the rotation axis P. The magnetic wedge 13 spans between adjacent teeth 110 so as to close the inside of the slot 11S. The magnetic wedge 13 is formed of a magnetic material containing magnetic powder such as iron powder. The magnetic wedge 13 may be manufactured by injection molding a resin containing magnetic powder. The magnetic wedge 13 may be made of an amorphous metal.

[0036] The magnetic wedge 13 preferably has a magnetic powder content of 30% or more and 80% or less. The magnetic powder content 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. This significantly reduces iron loss and torque ripple while maintaining torque.

[0037] As shown in Fig. 2, the magnetic wedge 13 has a hat-shaped cross section. In detail, the magnetic wedge 13 has a protruding portion 131 having an opposing surface 13A that faces the rotor 20 and a side surface 13B that extends from the opposing surface 13A in a direction away from the rotor 20. Since the magnetic wedge 13 has the protruding portion 131, a gap can be formed between the magnetic wedge 13 and the tooth portion 110. This makes it possible to suppress the transmission of magnetic flux from the vicinity of the inner surface 113 of the tooth portion 110 to the vicinity of the opposing surface 13A of the magnetic wedge 13. This makes it possible to equalize the distribution of magnetic flux density in the circumferential direction near the inner surface of the stator 10.

[0038] The opposing surface 13A is located along an extension surface M of the inner surface 113 of the stator 10. As a result, the magnetic wedge 13 is fixed to the tooth portion 110 with the inner surface of the flange portion 132 in contact with the inner surface of the groove 112 of the tooth portion 110, so that the opposing surface 13A can be precisely positioned along the extension surface M of the inner surface 113 of the stator 10. Therefore, a change in magnetic flux density in the circumferential direction near the inner surface of the stator 10 can be suppressed.

[0039] The magnetic wedge 13 has a flange 132 that fits into the wall surface 111 of the tooth portion 110. The magnetic wedge 13 may be fitted into a groove 112 provided in the wall surface 111 of the tooth portion 110.

[0040] The magnetic wedge 13 has a recess 134 on the outer surface 13D that is recessed in a direction toward the rotor 20. This allows a gap to be formed in the recess 134. This allows the radial position of the portion where the magnetic wedge 13 and the tooth portion 110 contact each other (for example, the portion where the flange portion 132 and the groove 112 contact each other) and the gap to be shifted. This makes it difficult for magnetic flux to be transmitted from one of the adjacent tooth portions 110 to the other adjacent tooth portion 110 via the magnetic wedge 13. This makes it possible to suppress a decrease in torque caused by a short circuit of the magnetic flux loop.

[0041] 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 foamed and expanded when heated, or may be foamed and expanded over time. The foam material 133 may be a liquid paint, or may be a sheet-like material that can be attached to the outer surface 13D of the magnetic wedge 13. This can improve the insulation between the magnetic wedge 13 and the winding 12. In addition, if the outer surface 13D of the flange portion 132 of the magnetic wedge 13 is provided with the foam material 133, the magnetic wedge 13 can be inserted into the groove 112 of the tooth portion 110 with the foam material 133 provided thereon, and the magnetic wedge 13 can be fixed in a state of being securely fitted into the groove 112 by the expansion of the foam material 133.

[0042] It is preferable that the magnetic wedge 13 and the winding 12 are separated by a gap, whereby the insulation between the magnetic wedge 13 and the winding 12 can be improved.

[0043] A gap e may be provided in the circumferential direction between the flange 132 of the magnetic wedge 13 and the groove 112. The gap e may be filled with a foam material 133. This improves insulation and reduces the area where the magnetic flux is short-circuited from the tooth 110 to the magnetic wedge 13. This allows the distribution of the magnetic flux density in the circumferential direction near the inner surface 113 of the stator 10 to be appropriately uniform.

[0044] (Relationship between the protruding part of the magnetic wedge and the width of the winding) Next, the relationship between the width X of the facing surface 13A of the protruding portion 131 of the magnetic wedge 13 and the width Y of the winding 12 will be described. FIG. 3 is a diagram showing cases (1) to (4) in which the relationship between the width X of the opposing surface 13A of the protruding portion 131 of the magnetic wedge 13 and the width Y of the innermost surface 12A of the winding 12 is different, and the relationship between the iron loss, torque, and torque ripple. As shown in Fig. 3, a common rotor 20 was used, and numerical analysis and experiments were performed to measure the iron loss, torque, and torque ripple for cases (1) to (4) in which the structure of the stator 10 was changed. In each case, the magnetic powder content of the magnetic wedge 13 was changed. Case (1) is a case in which width X of facing surface 13A of protrusion 131 of magnetic wedge 13 is set to less than 50% of width Y of innermost surface 12A of winding 12. Case (2) is a case in which width X of facing surface 13A of protrusion 131 of magnetic wedge 13 is set to 50% or more and less than 90% of width Y of innermost surface 12A of winding 12. Case (3) is a case in which width X of facing surface 13A of protrusion 131 of magnetic wedge 13 is set to 90% or more and 100% or less of width Y of innermost surface 12A of winding 12. Case (4) is a case in which width X of facing surface 13A of protrusion 131 of magnetic wedge 13 is more than 100% of width Y of innermost surface 12A of winding 12. As a result of numerical analysis and experiments, it was confirmed that, as shown in FIG. 3, when the magnetic powder content of the magnetic wedge 13 is in the range of 30% to 80%, preferably in the range of 40% to 70%, and more preferably in the range of 45% to 65%, it is possible to significantly reduce iron loss while maintaining torque, and to reduce torque ripple.

[0045] In addition, the results of numerical analysis were compared regarding the distribution of iron loss and magnetic flux density in the cross sections of the stator core 11 and the rotor 20. FIG. 4 is a comparative diagram showing the iron loss distribution and the magnetic flux density distribution for case (1), case (3), and case (4). 4, it was confirmed that case (3) can reduce the iron loss of rotor 20, particularly the iron loss near the outer surface of rotor 20, compared to 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 rotor 20 compared to case (1). It was also confirmed that case (3) can reduce the magnetic flux fluctuation by mitigating the concentration of magnetic flux at the connection portion of stator core 11, particularly between tooth portion 110 and magnetic wedge 13, compared to case (4).

[0046] In a cross section perpendicular to the rotation axis P of the rotor 20, that is, as shown in Figs. 1 to 4, it is preferable that the width X of the opposing surface 13A at the protrusion 131 of the magnetic wedge 13 is equal to or smaller than the width Y of the innermost surface 12A of the winding 12 (cases (1), (2), and (3)). Note that the innermost surface 12A refers to the inner surface of the winding 12 that is closest to the rotation axis P and the rotor 20, and in the case where a plurality of windings 12 are bundled together in a stack in the slot 11S, it refers to the inner surface of the innermost winding 12. Note that the width Y of the innermost surface 12A refers to the maximum dimension in the circumferential direction of the innermost winding 12, and in the case where the winding 12 is a rectangular wire as shown in the figures, it refers to the dimension of the side (long side) along the circumferential direction in the cross section of the rectangular wire. By setting the relationship between width X of opposing surface 13A of protrusion 131 of magnetic wedge 13 and width Y of innermost surface 12A of winding 12 in this manner, it is possible to reduce iron loss and torque ripple without significantly affecting torque, which is the main performance of rotating electric machine 1, as shown in FIG. 3.

[0047] 1 to 4, it is more preferable that the width X of the facing surface 13A at the protrusion 131 of the magnetic wedge 13 is 50% or more of the width Y of the innermost surface 12A of the winding 12 (cases (2) and (3)). By setting the relationship between the width X of the facing surface 13A at the protrusion 131 of the magnetic wedge 13 and the width Y of the innermost surface 12A of the winding 12 in this way, it is possible to significantly reduce iron loss and torque ripple without significantly affecting the torque, which is the main performance of the rotating electric machine 1, as shown in FIG.

[0048] The technical scope of the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention.

[0049] In addition, within the scope of the invention, the components in the above-described embodiments may be replaced with well-known components, and the above-described modified examples may be combined as appropriate. [Explanation of symbols]

[0050] 1 Rotating Electric Machine 10 Stator 11 Stator core 11S Slot 12 Windings 12A innermost surface 13 Magnetic wedge 13A Opposite surface 13B Side 13D Exterior 20 Rotors 110 Tooth 111 Wall 112 Groove 113 Inside 131 Convex 132 Flange 133 Foam material 134 Recess M extension surface P Rotational axis X (opposite faces) width Y (innermost) width

Claims

1. a stator core having a plurality of teeth forming slots; A winding disposed in the slot; a magnetic wedge provided between the winding and the rotor, the magnetic wedge includes a protrusion having a facing surface facing the rotor and a side surface extending in a direction away from the rotor; The side surface and the tooth portion are spaced apart, In a cross section perpendicular to the rotation axis of the rotor, the width of the opposing surface is equal to or smaller than the width of the innermost surface of the winding. A stator comprising:

2. The width of the facing surface is 50% or more of the width of the innermost surface of the winding.

2. The stator according to claim 1 .

3. The opposing surface is located along an extension surface of the inner surface of the stator.

3. The stator according to claim 1 or 2.

4. The magnetic wedge has a magnetic powder content of 30% to 80%.

4. The stator according to claim 1, wherein the first and second rotors are arranged in a first direction.

5. The magnetic wedge includes a foam material having insulating properties and covering an outer surface of the magnetic wedge.

5. A stator according to claim 1, wherein the first and second rotors are arranged in a first direction.

6. The tooth portion has a groove along a rotation axis of the rotor, the magnetic wedge includes a flange having the foam material on an outer surface thereof; The flange is fitted into the groove.

6. The stator according to claim 5.

7. The magnetic wedge and the winding are separated by an air gap.

7. A stator according to claim 1, wherein the first and second rotors are arranged in a first direction.

8. The magnetic wedge has a recess on its outer surface that is recessed in a direction toward the rotor.

8. A stator according to claim 1, wherein the first and second rotors are arranged in a first direction.

9. A rotating electric machine comprising the stator according to any one of claims 1 to 8.

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