Stator and rotating electrical machine

Abstract

The present invention provides a stator and a rotating electric machine that can suppress iron loss and torque ripple of the stator. The stator includes: a stator core having a plurality of tooth portions (110) that form slots (11S); a winding (12) disposed in the slots (11S); and a magnetic wedge (13) provided between the winding (12) and a rotor (20). The magnetic wedge (13) has a convex portion (131), and the convex portion (131) has an opposing surface (13A) that faces the rotor (20) and a side surface (13B) that continuously extends in a direction separating from the rotor (20) and is continuous with the opposing surface (13A). The side surface (13B) is separated from the tooth portion (110).

Description

Technical Field

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

[0002] Conventionally, there has been a rotating electric machine having a magnetic wedge on the rotor side of a coil sandwiched between teeth in a stator (for example, refer to Patent Document 1 (Japanese Patent Application Laid-Open No. 2002-281709)). Summary of the Invention

[0003] [Summary of the Invention]

[0004] [Problems to be Solved by the Invention]

[0005] However, in the rotating electric machine described in Patent Document 1, the iron loss of the stator may deteriorate or the magnetic flux of the stator may fluctuate due to the influence of the magnetic wedge.

[0006] An object of the present invention is to provide a stator and a rotating electric machine capable of suppressing the iron loss and torque ripple of the stator.

[0007] [Means for Solving the Problems]

[0008] In order to solve the above-described problems, the present invention proposes the following means.

[0009] (1) A stator according to an aspect of the present invention includes: a stator core having a plurality of tooth portions forming slots; a winding disposed in the slots; and a magnetic wedge disposed between the winding and a rotor, wherein the magnetic wedge has a convex portion having an opposed surface facing the rotor and a side surface continuously extending in a direction separating from the rotor from the opposed surface, and the side surface is separated from the tooth portion.

[0010] According to the means (1), the side surface is separated from the tooth portion. Thereby, it is possible to smooth the change in the circumferential distribution of the magnetic flux density near the inner surface of the stator. Thereby, it is possible to suppress the iron loss and torque ripple of the stator.

[0011] (2) In the stator according to the means (1) above, in a cross section perpendicular to the rotation axis of the rotor, the width of the opposed surface may be equal to or less than the width of the innermost surface of the winding.

[0012] According to the means (2), the width of the opposed surface is equal to or less than the width of the innermost surface of the winding. Thereby, it is possible to reduce the iron loss and torque ripple without significantly affecting the main performance of the rotating electric machine, i.e., the torque.

[0013] (3) In the stator according to the means (2) above, the width of the opposed surface may be 50% or more of the width of the innermost surface of the winding.

[0014] According to the solution of (3), the width of the opposing surface is 50% or more of the width of the innermost surface of the winding. Thus, it will not have a great impact on the main performance of the rotating electrical machine, i.e., torque, and can significantly reduce iron loss and torque ripple.

[0015] (4) In the stator of any one of the above (1) to (3) solutions, it may also be that the opposing surface is located at a position along the extension surface of the inner surface of the stator.

[0016] According to the solution of (4), the opposing surface is located at a position along the extension surface of the inner surface of the stator. Thus, the opposing surface of the magnetic wedge can be accurately arranged along the extension surface of the inner surface of the stator. Thus, the change in the circumferential magnetic flux density near the inner surface of the stator can be suppressed.

[0017] (5) In the stator of any one of the above (1) to (4) solutions, it may also be that the magnetic wedge has a magnetic powder content of 30% or more and 80% or less.

[0018] According to the solution of (5), the magnetic wedge has a magnetic powder content of 30% or more and 80% or less. Thus, torque can be significantly maintained while reducing iron loss, and torque ripple can be reduced.

[0019] (6) In the stator of any one of the above (1) to (5) solutions, it may also be that the magnetic wedge is provided with a foaming material that covers the outer surface of the magnetic wedge and has insulation properties.

[0020] According to the solution of (6), the magnetic wedge is provided with a foaming material that covers the outer surface of the magnetic wedge and has insulation properties. Thus, the insulation between the magnetic wedge and the winding can be improved.

[0021] (7) In the stator of the solution of the above (6), it may also be that the tooth portion has a groove along the rotation axis of the rotor, and the magnetic wedge is provided with a flange portion having the foaming material on the outer surface, and the flange portion is fitted into the groove.

[0022] According to the solution of (7), the tooth portion has a groove along the rotation axis of the rotor. Thus, the magnetic wedge can be reliably positioned and fixed relative to the tooth portion. The magnetic wedge is provided with a flange portion (for example, the flange portion 132 in the embodiment) having the foaming material on the outer surface, and the flange portion is fitted into the groove. Thus, the flange portion of the magnetic wedge can be reliably fitted into the groove of the tooth portion by the pressure of the foaming material.

[0023] (8) In the stator of any one of the above (1) to (7) solutions, it may also be that the magnetic wedge is separated from the winding by a gap.

[0024] According to the solution of (8), the magnetic wedge is separated from the winding with a gap therebetween. Thus, the insulation between the magnetic wedge and the winding can be improved.

[0025] (9) In the stator of any one of the above (1) to (8) solutions, it is also possible that the magnetic wedge has a concave portion on the outer surface that is recessed in the direction toward the rotor.

[0026] According to the solution of (9), the magnetic wedge has a concave portion on the outer surface that is recessed in the direction toward the rotor. Thus, a reduction in torque caused by a loop short circuit of magnetic flux can be suppressed.

[0027] (10) A rotating electric machine according to one solution of the present invention may include the stator.

[0028] According to the solution of (10), the rotating electric machine includes the stator. Thus, the iron loss and torque ripple of the stator can be suppressed.

[0029]

Invention Effects

[0030] According to the present invention, it is possible to provide a stator and a rotating electric machine that can suppress the iron loss and torque ripple of the stator.

Description of the Drawings

[0031] Figure 1 is a cross-sectional view of the rotating electric machine of the present embodiment.

[0032] Figure 2 is Figure 1 a detailed view of part A of

[0033] Figure 3 is a graph showing the relationships between cases (1) to (4) where the widths of the opposing surfaces in the convex portion of the magnetic wedge and the width of the innermost surface of the winding are different, and iron loss, torque, and torque ripple.

[0034] Figure 4 is a comparison graph showing the iron loss distribution and magnetic flux density distribution for cases (1), (3), and (4).

[0035]

Reference Signs

[0036] 1 Rotating electric machine

[0037] 10 Stator

[0038] 11 Stator core

[0039] 11S Slot

[0040] 12 Winding

[0041] 12A Innermost surface

[0042] 13 Magnetic wedge

[0043] 13A Opposite side

[0044] 13B Side

[0045] 13D outer surface

[0046] 20 Rotor

[0047] 110 teeth

[0048] 111 wall

[0049] 112 slots

[0050] 113 Inner surface

[0051] 131 convex part

[0052] 132 flange

[0053] 133 Foam material

[0054] 134 recess

[0055] M Extended surface

[0056] P Rotation axis

[0057] X Width (of facing surface)

[0058] Y (innermost surface) width DETAILED DESCRIPTION

[0059] Hereinafter, a stator 10 and a rotating electrical machine 1 including the stator 10 according to an embodiment of the present invention will be described with reference to the accompanying drawings. It should be noted that the direction orthogonal to the rotation axis P of the rotor 20 is sometimes referred to as a radial direction, and the direction describing a circle with the rotation axis P of the rotor 20 as the center is sometimes referred to as a circumferential direction. It should be noted that the direction away from the rotation axis P is sometimes referred to as an outer direction, and the direction toward the rotation axis P is sometimes referred to as an inner direction. It should be noted that the outer surface is sometimes referred to as an outer surface, and the inner surface is sometimes referred to as an inner surface.

[0060] <Rotary electrical machines>

[0061] Figure 1 It is a cross-sectional view of the rotating electrical machine 1 according to the present embodiment. Figure 2 yes Figure 1 It should be noted that the cross section of the rotating electrical machine 1 is rotationally symmetrical corresponding to the number of poles of the rotor. Figure 1 Only a part is shown in the figure, and the other parts are omitted.

[0062] like Figure 1 or Figure 2As shown, the rotating electrical 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. The rotating electrical machine 1 is, for example, a synchronous motor. The rotating electrical machine 1 includes, for example: an 8-pole rotor 20; and a stator 10 having 48 slots 11S for accommodating windings 12.

[0063] <Rotor>

[0064] The rotor 20 is a cylindrical structure that rotates about the rotation axis P. The rotor 20 has a structure in which magnets with different polarities are alternately arranged in the circumferential direction. The rotor 20 includes, for example, permanent magnets. The number of poles of the rotor 20 is, for example, 8 poles.

[0065] <Stator>

[0066] The stator 10 includes: a stator core 11 having a plurality of tooth portions 110 forming the slots 11S; a winding 12 disposed in the slots 11S; and a magnetic wedge 13 provided between the winding 12 and the rotor 20.

[0067] The magnetic wedge 13 includes a convex portion 131 having an opposed surface 13A opposed to the rotor 20 and a side surface 13B that continuously extends in a direction separating from the rotor 20 from the opposed surface 13A.

[0068] Here, the side surface 13B is separated from the tooth portion 110. Thus, since the side surface 13B of the convex portion 131 of the magnetic wedge 13 is separated from the tooth portion 110, it is possible to avoid magnetic flux concentration near the inner surface of the tooth portion 110. Therefore, it is possible to make the change in magnetic flux density generated between the vicinity of the inner surface of the tooth portion 110 and the vicinity of the inner surface of the magnetic wedge 13 smooth, and it is possible to make the magnetic flux density near the inner surface of the stator 10 uniform in the circumferential direction. As a result, it is possible to suppress iron loss of the stator 10 and torque ripple caused by magnetic flux fluctuation.

[0069] <Stator core>

[0070] The stator core 11 is formed, for example, by laminating electromagnetic steel sheets. The stator core 11 is a cylindrical shape having a cavity for accommodating the rotor 20 at the center. The stator core 11 has a plurality of tooth portions 110 extending from the outer peripheral portion 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 tooth portion 110 coincides with the rotation axis P.

[0071] The stator core 11 alternately arranges the tooth portions 110 and the slots 11S along the circumferential direction of the stator 10. The stator core 11 has, for example, 48 tooth portions 110 and 48 slots 11S.

[0072] 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 foaming material 133 to be described later on the outer surface 13D, the flange portion 132 is fitted into the groove 112. That is, the flange portion 132 having the foaming material 133 on the outer surface 13D can be fitted into the groove 112. When the flange portion 132 is inserted into the groove 112 of the tooth portion 110 and the foaming material 133 is heated in a state where the foaming material 133 is applied to at least the outer surface 13D of the flange portion 132 of the magnetic wedge 13, the foaming material 133 foams and expands, generating a force that presses the flange portion 132 inward. And the magnetic wedge 13 is fitted into the groove 112 in a state where the radial position is determined and is reliably fixed.

[0073] <Winding>

[0074] The winding 12 is arranged so as to pass through the slot 11S. The winding 12 is, for example, a flat wire made of copper. When the winding 12 is a flat wire, the winding 12 is bundled in the slot 11S so as to overlap in the radial direction in a state where the short side in the cross section of the flat wire is along the radial direction separated from the rotation axis P and the long side is along the circumferential direction.

[0075] It should be noted that an insulating sheet is interposed between the winding 12 and the wall surface 111 of the tooth portion 110, and an insulating material such as varnish is filled.

[0076] <Magnetic wedge>

[0077] The magnetic wedge 13 is provided between the winding 12 and the rotor 20 in order to prevent the winding 12 from coming off 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 is installed between adjacent tooth portions 110 so as to block the inner side of the slot 11S.

[0078] The magnetic wedge 13 is formed of a magnetic material containing magnetic powder such as iron powder, for example. The magnetic wedge 13 can be manufactured, for example, by injection molding a resin containing magnetic powder. The magnetic wedge 13 can be, for example, an amorphous metal.

[0079] The magnetic wedge 13 preferably has a magnetic powder content of 30% or more and 80% or less. It should be noted that the magnetic powder content is the ratio of the volume of the magnetic powder to the total volume of the components constituting the magnetic wedge 13 other than the foaming material 133. Thereby, the torque can be significantly maintained while reducing the iron loss, and the torque ripple can be reduced.

[0080] As Figure 2As shown, the cross-section of the magnetic wedge 13 forms a cap shape. Specifically, the magnetic wedge 13 includes a convex portion 131, and the convex portion 131 has an opposed surface 13A facing the rotor 20 and a side surface 13B that is continuous with the opposed surface 13A and extends in a direction separating from the rotor 20. Since the magnetic wedge 13 includes the convex portion 131, a gap can be formed between the magnetic wedge 13 and the tooth portion 110. Therefore, the transfer of magnetic flux from the vicinity of the inner surface 113 of the tooth portion 110 to the vicinity of the opposed surface 13A of the magnetic wedge 13 can be suppressed. Thereby, the distribution of the magnetic flux density in the circumferential direction near the inner surface of the stator 10 can be made uniform.

[0081] The opposed surface 13A is located at a position along the extended surface M of the inner surface 113 of the stator 10. Thus, the magnetic wedge 13 is fixed to the tooth portion 110 in a state where the inner surface of the flange portion 132 is in contact with the inner surface of the groove 112 of the tooth portion 110, so that the opposed surface 13A can be arranged with high precision along the extended surface M of the inner surface 113 of the stator 10. Thereby, the change in the magnetic flux density in the circumferential direction near the inner surface of the stator 10 can be suppressed.

[0082] The magnetic wedge 13 includes a flange portion 132 that fits into the wall surface 111 of the tooth portion 110. The magnetic wedge 13 can fit into a groove 112 provided on the wall surface 111 of the tooth portion 110.

[0083] The outer surface 13D of the magnetic wedge 13 has a recess 134 that is recessed in the direction toward the rotor 20. Thus, a gap can be formed in the recess 134. Moreover, the position in the radial direction of the portion where the magnetic wedge 13 is in contact with the tooth portion 110 (for example, the portion where the flange portion 132 and the groove 112 are in contact) can be offset from the position of this gap. Therefore, it is possible to make it difficult for magnetic flux to be transferred from one of the adjacent tooth portions 110 to the other adjacent tooth portion 110 via the magnetic wedge 13. Thereby, a reduction in torque caused by a loop short circuit of magnetic flux can be suppressed.

[0084] The magnetic wedge 13 may include a foaming material 133 that covers the outer surface 13D of the magnetic wedge 13 and has insulating properties. The foaming material 133 may be structured to foam and expand when heated, or may be structured to foam and expand over time. The foaming material 133 may be a liquid coating or a sheet-like material that can be attached 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. Moreover, when the magnetic wedge 13 is inserted into the groove 112 of the tooth portion 110 in a state where the foaming material 133 is provided on the outer surface 13D of the flange portion 132 of the magnetic wedge 13, the magnetic wedge 13 can be fixed in a state of being reliably fitted to the groove 112 by the expansion of the foaming material 133.

[0085] The magnetic wedge 13 and the winding 12 are preferably separated by a gap. Thereby, the insulation between the magnetic wedge 13 and the winding 12 can be improved.

[0086] A clearance e may be provided circumferentially between the flange portion 132 of the magnetic wedge 13 and the slot 112. A foamed material 133 may be filled in the clearance e. Thereby, insulation can be improved, and the area where magnetic flux is short-circuited from the tooth portion 110 to the magnetic wedge 13 can be reduced. Thereby, the circumferential distribution of the magnetic flux density near the inner surface 113 of the stator 10 can be appropriately made uniform.

[0087] (Relationship between the convex portion of the magnetic wedge and the width of the winding)

[0088] Next, the relationship between the width X of the opposed surface 13A in the convex portion 131 of the magnetic wedge 13 and the width Y of the winding 12 will be described.

[0089] Figure 3 It is a graph showing the relationship between the width X of the opposed surface 13A in the convex portion 131 of the magnetic wedge 13 and the width Y of the innermost surface 12A of the winding 12 in different cases (1) to (4) and the relationship with iron loss, torque, and torque ripple.

[0090] As Figure 3 shown, for cases (1) to (4) in which the structure of the stator 10 is changed while using the common rotor 20, numerical analysis and experiments for measuring iron loss, torque, and torque ripple were performed. Note that, in each case, the magnetic powder content rate of the magnetic wedge 13 was made variable.

[0091] In case (1), the width X of the opposed surface 13A in the convex portion 131 of the magnetic wedge 13 is set to be less than 50% of the width Y of the innermost surface 12A of the winding 12.

[0092] In case (2), the width X of the opposed surface 13A in the convex portion 131 of the magnetic wedge 13 is set to be 50% or more and less than 90% of the width Y of the innermost surface 12A of the winding 12.

[0093] In case (3), the width X of the opposed surface 13A in the convex portion 131 of the magnetic wedge 13 is set to be 90% or more and 100% or less of the width Y of the innermost surface 12A of the winding 12.

[0094] In case (4), the width X of the opposed surface 13A in the convex portion 131 of the magnetic wedge 13 is set to be more than 100% of the width Y of the innermost surface 12A of the winding 12.

[0095] As a result of the numerical analysis and experiments Figure 3 shown, it was confirmed that when the magnetic powder content rate 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%, the torque can be significantly maintained while reducing the iron loss, and the torque ripple can be reduced.

[0096] The numerical analysis results of the iron loss and the magnetic flux density distribution in the cross sections of the stator core 11 and the rotor 20 were compared respectively.

[0097] Figure 4 It is a comparison diagram showing the iron loss distribution and the magnetic flux density distribution for Case (1), Case (3), and Case (4).

[0098] As Figure 4 shown, it can be confirmed that, compared with Case (1), Case (3) can reduce the iron loss of the rotor 20, particularly the iron loss near the outer surface of the rotor 20. Moreover, it can be confirmed that, compared with Case (4), Case (3) can reduce the iron loss of the stator core 11, particularly the iron loss near the inner surface of the tooth portion 110 of the stator core 11.

[0099] It can be confirmed that, compared with Case (1), Case (3) can reduce the magnetic flux variation of the rotor 20. It can be confirmed that, compared with Case (4), Case (3) can alleviate the magnetic flux concentration at the connection portion between the tooth portion 110 and the magnetic wedge 13 of the stator core 11, and reduce the magnetic flux variation.

[0100] In the cross section perpendicular to the rotation axis P of the rotor 20, that is, as Figures 1 to 4 shown, the width X of the opposing surface 13A in the convex portion 131 of the magnetic wedge 13 is preferably equal to or less than the width Y of the innermost surface 12A of the winding 12 (Case (1), Case (2), and Case (3)). It should be noted that the innermost surface 12A refers to the inner surface of the winding 12 that is closest to the rotation axis P and closest to the rotor 20. When a plurality of windings 12 are overlapped and bundled in the slot 11S, it refers to the inner surface of the innermost winding 12. It should be noted that the width Y of the innermost surface 12A refers to the maximum dimension in the circumferential direction of the innermost winding 12. When the winding 12 is a flat wire as shown in the figure, it refers to the dimension of the side (long side) along the circumferential direction in the cross section of the flat wire. By making the relationship between the width X of the opposing surface 13A in the convex portion 131 of the magnetic wedge 13 and the width Y of the innermost surface 12A of the winding 12 like this, thus as Figure 3 shown, it will not have a great impact on the main performance of the rotating electrical machine 1, that is, the torque, and can reduce the iron loss and reduce the torque ripple.

[0101] In the cross section perpendicular to the rotation axis P of the rotor 20, that is, as Figures 1 to 4 shown, the width X of the opposing surface 13A in the convex portion 131 of the magnetic wedge 13 is more preferably 50% or more of the width Y of the innermost surface 12A of the winding 12 (Case (2) and Case (3)). By making the relationship between the width X of the opposing surface 13A in the convex portion 131 of the magnetic wedge 13 and the width Y of the innermost surface 12A of the winding 12 like this, thus asFigure 3 As shown, it will not have a great impact on the main performance of the rotating electrical machine 1, i.e., torque, and can greatly reduce iron loss and torque ripple.

[0102] It should be noted that the technical scope of the present invention is not limited to the foregoing embodiments, and various changes can be made without departing from the gist of the present invention.

[0103] In addition, without departing from the gist of the present invention, the constituent elements in the foregoing embodiments can be appropriately replaced with well-known constituent elements, and the foregoing modification examples can also be appropriately combined.

Claims

1. A stator, comprising: A stator core having a plurality of tooth portions forming slots; A winding disposed in the slots; and A magnetic wedge disposed between the winding and the rotor, wherein The magnetic wedge has a convex portion having an opposing surface facing the rotor and a side surface continuously extending in a direction separating from the rotor with respect to the opposing surface, The side surface is separated from the tooth portion, In a cross-section perpendicular to the rotation axis of the rotor, the width of the opposing surface is less than or equal to the width of the innermost surface of the winding, The tooth portion has a groove along the rotation axis of the rotor, The magnetic wedge has a flange portion fitted into the groove, In a state where the flange portion is fitted into the groove, a gap is provided in the circumferential direction between the flange portion and the groove, The magnetic wedge has a foaming material covering the outer surface of the magnetic wedge and having insulation properties, In a state where the flange portion is fitted into the groove, the foaming material fixes the magnetic wedge in a state of pressing the inner surface of the flange portion against the inner surface of the groove of the tooth portion, The foaming material is housed in the groove together with the flange portion.

2. The stator according to claim 1, wherein When the width of the opposing surface is X and the width of the innermost surface of the winding is Y, 0.5Y ≤ X ≤ Y.

3. The stator according to claim 1, wherein The opposing surface is located at a position along the extension surface of the inner surface of the stator.

4. The stator according to claim 1, wherein The magnetic wedge has a magnetic powder content of 30% or more and 80% or less.

5. The stator according to claim 1, wherein The foaming material is provided on the outer surface of the flange portion.

6. The stator according to claim 1, wherein The magnetic wedge is separated from the winding with a gap therebetween.

7. The stator according to claim 1, wherein The magnetic wedge has a recess on the outer surface that is recessed in a direction toward the rotor, A gap is formed between the recess and the winding, The positions of the portion where the magnetic wedge is in contact with the tooth portion and the gap in the radial direction of the rotor are different from each other, The winding is disposed at a position radially outside the end portion of the magnetic wedge that is located at the outermost position in the radial direction.

8. A rotating electric machine, wherein The rotating electric machine includes the stator according to any one of claims 1 to 7.

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