Coil, motor, and manufacturing method of coil

Abstract

To provide a manufacturing method of coil capable of suppressing distortion of a coil shape when a multi-layer coil is formed by winding rectangular wire.SOLUTION: A coil 30 attached to a tooth 22 extending from an annular core back 21 surrounding a central axis of a motor to one side of a radial direction has a first winding body 31 configured by winding rectangular wire, and a second winding body 32 configured by winding the rectangular wire, located in the other side of the radial direction of the first winding body, and connected to the first winding body. When N is an arbitrary integer equal to or greater than one, and M is an arbitrary integer greater than N, the first winding body is a N layer winding body regularly wound in two rows in the radial direction, and the second winding body is a M layer winding body regularly wound in two rows in the radial direction.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a coil, a motor, and a method for manufacturing a coil. [Background technology]

[0002] Coils formed by winding rectangular wire are known. For example, Japanese Patent Application Laid-Open Publication No. 2004-180396 describes a coil in which the cross section of the winding is trapezoidal. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication: JP2004-180396A Summary of the Invention [Problem to be solved by the invention]

[0004] When winding rectangular wire to create a multi-layer coil, it can be difficult to align the rectangular wires precisely, which can result in a distorted coil shape.

[0005] In view of the above circumstances, an object of the present invention is to provide a coil having a structure capable of suppressing deformation of the coil, and a motor including such a coil, and a method for manufacturing the coil capable of suppressing deformation of the coil. [Means for solving the problem]

[0006] One embodiment of the coil of the present invention is a coil attached to teeth extending radially from an annular core back surrounding a central axis of a motor, and includes a first winding body formed by winding a rectangular wire, and a second winding body formed by winding a rectangular wire, located on the other radial side of the first winding body, and connected to the first winding body. When N is an arbitrary integer of 1 or more and M is an arbitrary integer greater than N, the first winding body is a winding body of N layers wound in alignment in two rows aligned in the radial direction, and the second winding body is a winding body of M layers wound in alignment in two rows aligned in the radial direction.

[0007] One aspect of the motor of the present invention includes a rotor rotatable about a central axis, and a stator radially opposed to the rotor with a gap therebetween. The stator has an annular core back surrounding the central axis, teeth extending radially from the core back to one side, and the coils described above attached to the teeth.

[0008] One embodiment of the coil manufacturing method of the present invention is a method for manufacturing a coil to be attached to a tooth extending radially from an annular core back surrounding a central axis of a motor, and includes the steps of winding a rectangular wire to make a first winding, winding a rectangular wire to make a second winding, and arranging the second winding on the other radial side of the first winding and connecting the first winding and the second winding. When N is an integer equal to or greater than 1 and M is an integer greater than N, the first winding is an N-layer winding wound in two aligned rows in the radial direction, and the second winding is an M-layer winding wound in two aligned rows in the radial direction. Effect of the Invention

[0009] According to one aspect of the present invention, distortion of the coil shape can be suppressed. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a cross-sectional view that illustrates a motor according to a first embodiment. [Diagram 2]FIG. 2 is a cross-sectional view showing a part of the stator of the first embodiment, taken along line II-II in FIG. [Diagram 3] FIG. 3 is a perspective view showing a part of the coil of the first embodiment. [Figure 4] FIG. 4 is a flowchart showing the steps of the method for manufacturing the coil according to the first embodiment. [Diagram 5] FIG. 5 is a cross-sectional view showing a part of a procedure in a manufacturing method of the coil of the first embodiment. [Figure 6] FIG. 6 is a cross-sectional view showing another part of the procedure in the method for manufacturing the coil of the first embodiment. [Figure 7] FIG. 7 is a cross-sectional view showing a coil according to the second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] The Z-axis direction shown in each drawing is an up-down direction with the positive side being the "upper side" and the negative side being the "lower side". The central axis J shown in each drawing is a virtual line that is parallel to the Z-axis direction and extends in the up-down direction. In the following description, the axial direction of the central axis J, i.e., the direction parallel to the up-down direction, is simply referred to as the "axial direction", the radial direction centered on the central axis J is simply referred to as the "radial direction", and the circumferential direction centered on the central axis J is simply referred to as the "circumferential direction". In each embodiment, the radially inner side is one radial side, and the radially outer side is the other radial side.

[0012] Note that the terms "upper" and "lower" are simply names used to explain the relative positions of the various parts, and the actual relative positions may be other than those indicated by these names.

[0013] First Embodiment As shown in Fig. 1, the motor 1 of this embodiment is an inner rotor type motor. The central axis of the motor 1 is a central axis J. The motor 1 includes a housing 2, a rotor 3, a stator 10, a bearing holder 4, and bearings 5a and 5b. The housing 2 accommodates the rotor 3, the stator 10, the bearing holder 4, and the bearings 5a and 5b. The rotor 3 is rotatable about the central axis J. The rotor 3 includes a shaft 3a and a rotor body 3b.

[0014] The shaft 3a extends in the axial direction along the central axis J. The shaft 3a is, for example, cylindrical and extends in the axial direction around the central axis J. The shaft 3a is supported by bearings 5a and 5b so as to be rotatable about the central axis J. The rotor body 3b is fixed to the outer circumferential surface of the shaft 3a. Although not shown, the rotor body 3b has a rotor core fixed to the outer circumferential surface of the shaft 3a and a magnet fixed to the rotor core. The bearing holder 4 holds the bearing 5b.

[0015] The stator 10 faces the rotor 3 in the radial direction with a gap therebetween. In this embodiment, the stator 10 is located radially outward of the rotor 3. As shown in FIG. 2 , the stator 10 has a stator core 20, a plurality of coils 30, and an insulator 40. The stator core 20 has an annular core back 21 surrounding the central axis J, and a plurality of teeth 22 extending radially inward from the core back 21. The core back 21 is, for example, cylindrical with the central axis J as its center.

[0016] The teeth 22 are arranged at intervals along the circumferential direction. For example, the teeth 22 are arranged at equal intervals around one circumference along the circumferential direction. In this embodiment, the teeth 22 are molded integrally with the core back 21. Each tooth 22 has a substantially rectangular parallelepiped shape that extends linearly along the radial direction. The circumferential dimension of the teeth 22 is substantially constant over the entire radial direction.

[0017] Note that the radially inner ends of the teeth 22 may be provided with umbrella portions protruding on both circumferential sides. The teeth 22 may be separate members from the core back 21. In this case, the teeth 22 may be fixed to the core back 21, for example, by press-fitting protrusions provided at the radially outer ends of the teeth 22 into recesses provided on the radially inner surface of the core back 21.

[0018] The multiple coils 30 are attached to the multiple teeth 22, respectively. In this embodiment, the coils 30 are attached to the teeth 22 via insulators 40. Each tooth 22 passes radially inside each coil 30. The radially inner ends of the teeth 22 protrude radially inward beyond the coils 30.

[0019] The coil 30 is formed by winding a rectangular wire. Therefore, the space factor of the coil 30 can be improved compared to when a round wire is used. In this specification, the term "rectangular wire" refers to a wire having a rectangular or substantially rectangular cross-sectional shape. In this specification, the term "substantially rectangular shape" includes a rectangular shape with rounded corners. Although not shown in the figures, the rectangular wire constituting the coil 30 in this embodiment is an enameled wire having an enamel coating on its surface.

[0020] The coil 30 includes a pair of axially extending portions 30b extending in the axial direction on both circumferential sides of the tooth 22 to which the coil 30 is attached. The pair of axially extending portions 30b sandwich the tooth 22 in the circumferential direction. The axially extending portions 30b are formed by bundling together a portion of the rectangular wire that constitutes the coil 30. The contour shape of the axially extending portions 30b in a cross section perpendicular to the axial direction is, for example, a sector shape whose circumferential dimension decreases radially inward.

[0021] In this specification, the term "sector shape" includes a shape surrounded by two arcs with the same center of curvature but different radii, and two line segments extending in the radial direction of a circle centered on the center of curvature and connecting both ends of the two arcs. In addition, in this specification, the term "sector shape" includes a case where the shape is strictly a sector shape and a case where the shape is approximately a sector shape. In this specification, the term "approximate sector shape" includes a shape in which the arcs of the sector shape are approximated by a plurality of line segments. In this embodiment, the contour shape of the axially extending portion 30b in a cross section perpendicular to the axial direction is a shape surrounded by the above-mentioned two arcs and two line segments. Although not shown in the figure, the center of curvature of the contour shape of the axially extending portion 30b in a cross section perpendicular to the axial direction is located radially inside the core back 21 and is at a position different from the central axis J.

[0022] The coil 30 includes a first winding body 31 and a second winding body 32. The first winding body 31 and the second winding body 32 are each formed by winding a rectangular wire. In this embodiment, the first winding body 31 constitutes a radially inner portion of the coil 30. In this embodiment, the second winding body 32 constitutes a radially outer portion of the coil 30. In other words, the second winding body 32 is located radially outward of the first winding body 31.

[0023] The second winding body 32 is connected to the first winding body 31. More specifically, as shown in FIG. 3, one end 31c of the rectangular wire constituting the first winding body 31 is connected to one end 32c of the rectangular wire constituting the second winding body 32. As a result, the first winding body 31 and the second winding body 32 are connected in series to form one coil 30. The method of connecting the one end 31c and the one end 32c is not particularly limited. The one end 31c and the one end 32c may be fixed by soldering, by laser welding, or by ultrasonic bonding. In addition, the one end 31c and the one end 32c may each be provided with a recess that meshes with each other.

[0024] In the following description, N is an arbitrary integer equal to or greater than 1, and M is an arbitrary integer greater than N. In this case, the first winding body 31 is a winding body of N layers wound in two aligned rows aligned in the radial direction. The second winding body 32 is a winding body of M layers wound in two aligned rows aligned in the radial direction. As shown in FIG. 2, in this embodiment, the first winding body 31 is configured by stacking three layers of windings wound in aligned rows aligned in the radial direction. That is, in this embodiment, N is 3, and the first winding body 31 is a winding body of three layers wound in aligned rows aligned in the radial direction. As a result, the total number of turns of the first winding body 31 is 6.

[0025] In this embodiment, the second winding body 32 is configured by stacking four layers of aligned windings in two radially aligned rows. That is, in this embodiment, M is 4, and the second winding body 32 is a four-layered winding body that is aligned and wound in two radially aligned rows. As a result, the total number of turns of the second winding body 32 is 8. Therefore, the total number of turns of the coil 30 is 14.

[0026] The first winding body 31 has a pair of first axially extending portions 31b extending in the axial direction on both circumferential sides of the tooth 22 to which the first winding body 31 is attached. The contour shape of the first axially extending portions 31b in a cross section perpendicular to the axial direction is, for example, a sector shape whose circumferential dimension decreases toward the radially inner side. More specifically, the contour shape of the first axially extending portions 31b in a cross section perpendicular to the axial direction is a shape surrounded by two arcs and two line segments, similar to the above-mentioned axially extending portions 30b.

[0027] In this embodiment, the cross-sectional shape of the part of the rectangular wire constituting the first winding body 31 that constitutes the first axially extending portion 31b is a trapezoid whose circumferential dimension decreases toward the radially inward direction. More specifically, the cross-sectional shape of the part of the rectangular wire constituting the first winding body 31 that constitutes the first axially extending portion 31b is a trapezoid whose circumferential dimension decreases toward the radially inward direction. In the following description, the part of the rectangular wire constituting the first winding body 31 that constitutes the first axially extending portion 31b is referred to as the first coil wire portion 31a.

[0028] Each of the pair of first axially extending portions 31b is configured by bundling a plurality of first coil wire portions 31a. In this embodiment, each of the first axially extending portions 31b is configured by bundling six first coil wire portions 31a. More specifically, in this embodiment, each of the first axially extending portions 31b is configured by two rows in the radial direction, each row having three first coil wire portions 31a arranged in the circumferential direction. The circumferential dimension in the cross section of the first coil wire portion 31a constituting the radially outer row of the two rows arranged in the radial direction is larger than the circumferential dimension in the cross section of the first coil wire portion 31a constituting the radially inner row. The radial dimension in the cross section of the first coil wire portion 31a constituting the radially outer row is smaller than the radial dimension in the cross section of the first coil wire portion 31a constituting the radially inner row. The cross-sectional areas of the first coil wire portions 31a are the same as each other.

[0029] The second winding body 32 has a pair of second axially extending portions 32b extending in the axial direction on both circumferential sides of the tooth 22 to which the second winding body 32 is attached. The pair of second axially extending portions 32b are disposed adjacent to the radially outer sides of the pair of first axially extending portions 31b. The axially extending portion 30b of the coil 30 is constituted by the first axially extending portion 31b and the second axially extending portion 32b adjacent to each other in the radial direction. That is, the axially extending portion 30b has the first axially extending portion 31b provided on the first winding body 31 and the second axially extending portion 32b provided on the second winding body 32.

[0030] The contour shape of the second axially extending portion 32b in a cross section perpendicular to the axial direction is, for example, a sector shape whose circumferential dimension decreases toward the radially inner side. More specifically, the contour shape of the second axially extending portion 32b in a cross section perpendicular to the axial direction is a shape surrounded by two arcs and two line segments, similar to the above-mentioned axially extending portion 30b.

[0031] In this embodiment, the cross-sectional shape of the part of the rectangular wire constituting the second winding body 32 that constitutes the second axially extending portion 32b is a trapezoid whose circumferential dimension decreases toward the radially inward direction. More specifically, the cross-sectional shape of the part of the rectangular wire constituting the second winding body 32 that constitutes the second axially extending portion 32b is a trapezoid whose circumferential dimension decreases toward the radially inward direction. In the following description, the part of the rectangular wire constituting the second winding body 32 that constitutes the second axially extending portion 32b is referred to as the second coil wire portion 32a.

[0032] Each of the pair of second axially extending portions 32b is configured by bundling a plurality of second coil wire portions 32a. In this embodiment, each second axially extending portion 32b is configured by bundling eight second coil wire portions 32a. More specifically, in this embodiment, each second axially extending portion 32b is configured by two rows in the radial direction, each row having four second coil wire portions 32a arranged in the circumferential direction. Of the two rows arranged in the radial direction, the circumferential dimension in the cross section of the second coil wire portion 32a constituting the radially outer row is larger than the circumferential dimension in the cross section of the second coil wire portion 32a constituting the radially inner row. The circumferential dimension in the cross section of the second coil wire portion 32a is smaller than the circumferential dimension in the cross section of the first coil wire portion 31a.

[0033] The radial dimension in the cross section of the second coil wire portion 32a constituting the radially outer row is smaller than the radial dimension in the cross section of the second coil wire portion 32a constituting the radially inner row. The radial dimension in the cross section of the second coil wire portion 32a is larger than the radial dimension in the cross section of the first coil wire portion 31a. The cross-sectional areas of the second coil wire portions 32a are the same as each other.

[0034] 3, one end 31c connected to the second winding body 32 is drawn out obliquely upward from one of the pair of first axially extending portions 31b. One end 32c connected to the first winding body 31 is drawn out obliquely upward from one of the pair of second axially extending portions 32b. The first axially extending portion 31b from which the one end 31c is drawn out and the second axially extending portion 32b from which the one end 32c is drawn out are located on opposite sides in the circumferential direction with the tooth 22 sandwiched therebetween.

[0035] Although not shown, the cross-sectional shape of the rectangular wire constituting the first winding body 31 other than the first axially extending portion 31b is, for example, a square with rounded corners. The cross-sectional shape of the rectangular wire constituting the second winding body 32 other than the second axially extending portion 32b is, for example, a square with rounded corners.

[0036] As shown in FIG. 2, the insulator 40 is, for example, a sheet-like insulating member. The insulator 40 may be an insulating tape or insulating paper. In this embodiment, the insulator 40 is provided for each of the pair of axially extending portions 30b. The insulator 40 is wound around each of the pair of axially extending portions 30b. The insulator 40 provided on the axially extending portion 30b surrounds the axially extending portion 30b in a cross section perpendicular to the axial direction. Although not shown, the insulator 40 is provided over almost the entire axial direction of the axially extending portion 30b.

[0037] As shown in Fig. 4, the manufacturing method of the coil 30 described above includes a first winding step S1, a second winding step S2, a compression step S3, and a connection step S4. As shown in Fig. 5, the first winding step S1 is a step of winding a rectangular wire to make a first winding body 131. The second winding step S2 is a step of winding a rectangular wire to make a second winding body 132. The first winding step S1 and the second winding step S2 may be performed in either order, or may be performed simultaneously.

[0038] The first winding body 131 is a winding body before it becomes the above-mentioned first winding body 31. In the first winding body 131, the cross-sectional shape of the multiple first coil wire portions 131a constituting the first axial extension portion 131b is a square with rounded corners. The outline shape of the first axial extension portion 131b in a cross section perpendicular to the axial direction is, for example, approximately rectangular. The cross-sectional shape of the rectangular wire constituting the first winding body 131 is the same in all parts. The first winding body 131 is a three-layer winding body wound in two aligned rows aligned in the radial direction.

[0039] The second winding body 132 is a winding body before it becomes the above-mentioned second winding body 32. In the second winding body 132, the cross-sectional shape of the multiple second coil wire portions 132a constituting the second axial extension portion 132b is a square shape with rounded corners. The contour shape of the second axial extension portion 132b in a cross section perpendicular to the axial direction is, for example, approximately rectangular. The cross-sectional shape of the rectangular wire constituting the second winding body 132 is the same in every part. The cross-sectional shape of the rectangular wire constituting the second winding body 132 is the same as the cross-sectional shape of the rectangular wire constituting the first winding body 131. The second winding body 132 is a four-layer winding body wound in two rows aligned in the radial direction.

[0040] As shown in Fig. 6, the compression step S3 is a step of compressing and deforming the first winding body 131 and the second winding body 132. As shown in Fig. 4, in this embodiment, the compression step S3 includes a first compression step S3a and a second compression step S3b. The first compression step S3a is a step of compressing and deforming the first winding body 131. The second compression step S3b is a step of compressing and deforming the second winding body 132. In this embodiment, the first compression step S3a and the second compression step S3b are provided before the connection step S4. Either the first compression step S3a or the second compression step S3b may be performed first, or they may be performed simultaneously.

[0041] In the first compression step S3a of this embodiment, the contour shape of the first axially extending portion 131b in a cross section perpendicular to the axial direction is deformed into a sector shape whose circumferential dimension decreases toward the radially inward direction. As a result, the cross-sectional shape of the part of the rectangular wire constituting the first winding body 131 that constitutes the first axially extending portion 131b, i.e., the cross-sectional shape of the first coil wire portion 131a, is deformed into a trapezoid whose circumferential dimension decreases toward the radially inward direction. By the first compression step S3a, the first axially extending portion 131b becomes the first axially extending portion 31b, and the above-mentioned first winding body 31 is produced.

[0042] In the second compression step S3b of this embodiment, the contour shape of the second axially extending portion 132b in a cross section perpendicular to the axial direction is deformed into a sector shape whose circumferential dimension decreases toward the radially inward direction. As a result, the cross-sectional shape of the part of the rectangular wire constituting the second axially extending portion 132b that constitutes the second winding body 132, i.e., the cross-sectional shape of the second coil wire portion 132a, is deformed into a trapezoid whose circumferential dimension decreases toward the radially inward direction. By the second compression step S3b, the second axially extending portion 132b becomes the second axially extending portion 32b, and the above-mentioned second winding body 32 is produced.

[0043] As described above, in the compression process S3, the contour shape of the first axial extension portion 131b in a cross section perpendicular to the axial direction is deformed into a sector shape whose circumferential dimension decreases toward the radially inward direction, and the contour shape of the second axial extension portion 132b in a cross section perpendicular to the central axis J is deformed into a sector shape whose circumferential dimension decreases toward the radially inward direction.

[0044] In the first compression step S3a and the second compression step S3b, the method of compressing and deforming each of the winding bodies is not particularly limited. In the first compression step S3a and the second compression step S3b of the present embodiment, each axially extending portion of each of the winding bodies is pressed by a die surrounding the axially extending portion, thereby compressing and deforming each of the winding bodies.

[0045] The connecting step S4 is a step of disposing the second winding body 32 radially outside the first winding body 31 and connecting the first winding body 31 and the second winding body 32. In the connecting step S4 of this embodiment, one end 31c of the first winding body 31 and one end 32c of the second winding body 32 are connected. As described above, the method of connecting one end 31c and one end 32c is not particularly limited. Through the above steps, the coil 30 is manufactured.

[0046] According to this embodiment, the coil 30 includes a first winding body 31 and a second winding body 32 connected to the first winding body 31. When N is an arbitrary integer of 1 or more and M is an arbitrary integer greater than N, the first winding body 31 is a winding body of N layers wound in two rows aligned in the radial direction, and the second winding body 32 is a winding body of M layers wound in two rows aligned in the radial direction. When the rectangular wire is wound in two rows, it is easier to wind the rectangular wire by aligning them with high precision compared to when the rectangular wire is wound in three or more rows. Therefore, by connecting multiple winding bodies each aligned in two rows, it is possible to easily manufacture a coil 30 in which the rectangular wire is aligned with high precision in four or more rows. This makes it possible to prevent the shape of the coil 30 from becoming distorted.

[0047] Moreover, M is any integer larger than N. Therefore, the number of layers of the second winding body 32 located radially outside the first winding body 31 is larger than the number of layers of the first winding body 31. Here, when the motor 1 is an inner rotor type motor, the interval between the teeth 22 adjacent in the circumferential direction increases toward the radially outer side. Therefore, by making the number of layers of the second winding body 32 located radially outside the first winding body 31 larger than the number of layers of the first winding body 31, it is possible to arrange more windings between the teeth 22 with space efficiency. This allows the total number of turns of the coil 30 to be suitably increased.

[0048] Also, for example, when a multi-layered coil is made by simply winding rectangular wire in an aligned manner, the total number of turns of the coil is the number obtained by multiplying the number of layers by the number of alignments. Therefore, for example, when there is a limit to at least one of the number of alignments and the number of layers, there is a risk that the total number of turns of the coil that can be adopted may be limited. In contrast, according to this embodiment, since the number of layers of the first winding body 31 and the number of layers of the second winding body 32 are different from each other, it is easy to adjust the total number of turns of the coil 30 by adjusting the number of layers of each winding body. Therefore, the degree of freedom of the total number of turns of the coil 30 that can be adopted can be improved. In this embodiment, for example, the total number of turns of the coil 30 can be any even number equal to or greater than 6.

[0049] According to this embodiment, the contour shape of the axially extending portion 30b in a cross section perpendicular to the axial direction is a sector shape whose circumferential dimension decreases toward the radially inner side. This allows the coil 30 to be suitably packed and disposed between the teeth 22 adjacent to each other in the circumferential direction. This makes it easier to improve the space factor of the coil 30.

[0050] Also, for example, in the case of a conventional multi-layered coil, when the contour shape of the axial extension portion is made into a sector shape as described above, the cross-sectional shape of the coil wire portion located radially inward is smaller in circumferential dimension and larger in radial dimension. On the other hand, the cross-sectional shape of the coil wire portion located radially outward is larger in circumferential dimension and smaller in radial dimension. As a result, the cross-sectional shape of at least a part of the coil wire portion is likely to be flat. In this case, the eddy current loss of the coil is likely to be large. In addition, when a flat wire having a substantially square cross-sectional shape is deformed to make the cross-sectional shape of the flat wire into a flat shape, the deformation amount of the flat wire is likely to be large. Therefore, when the flat wire is deformed, there is a risk that the enamel coating provided on the surface will be broken. In addition, the deformation of each coil wire portion constituting the axial extension portion is likely to be non-uniform.

[0051] In contrast, according to this embodiment, the number of layers of the second winding body 32 located radially outside the first winding body 31 is greater than the number of layers of the first winding body 31. Therefore, the number of layers of the second winding body 32 constituting the radially outer portion of the axially extended portion 30b can be made relatively large, while the number of layers of the first winding body 31 constituting the radially inner portion of the axially extended portion 30b can be made relatively small. As a result, even if the contour shape of the axially extended portion 30b is deformed into a sector shape, the deformation amount of each coil wire portion constituting the axially extended portion 30b can be made small. Therefore, the cross-sectional shape of each coil wire portion can be prevented from becoming flat. Therefore, the eddy current loss of the coil 30 can be prevented from increasing. In addition, the enamel coating provided on the surface of the rectangular wire can be prevented from breaking. In addition, the deformation of each coil wire portion constituting the axially extended portion 30b can be prevented from becoming uneven.

[0052] Also, for example, when simply winding a rectangular wire in an aligned manner to make a multi-layered coil, depending on the number of layers, etc., it may be difficult to compress and deform the contour shape of the axially extended portion into a fan shape due to the large amount of deformation of the rectangular wire as described above. Therefore, when making the contour shape of the axially extended portion into a fan shape, there is a risk that the number of layers, etc. will be limited, and the total number of turns of the coil that can be adopted will be limited. In contrast, according to this embodiment, the contour shape of the axially extended portion can be made into a fan shape while suppressing the amount of deformation of each coil wire portion as described above. Therefore, it is possible to suppress the occurrence of limitations on the total number of turns of the coil 30 that can be adopted, and it is easy to adopt the desired total number of turns of the coil 30 within the range of an even number of 6 or more.

[0053] Furthermore, according to this embodiment, the first compression step S3a and the second compression step S3b are performed before the connection step S4. Therefore, the first winding body 31 and the second winding body 32 can be formed by deforming the first winding body 131 and the second winding body 32, respectively, and then the first winding body 31 and the second winding body 32 can be connected. This makes it easier to compress and deform each winding body compared to a case in which the first winding body 131 and the second winding body 132 are joined and then compressed and deformed together.

[0054] <Second embodiment> As shown in Fig. 7, the coil 230 of this embodiment further includes a third winding body 233. The third winding body 233 is configured by winding a rectangular wire. The third winding body 233 is located radially outside the second winding body 32. The third winding body 233 is connected to the second winding body 32. The second winding body 32 and the third winding body 233 can be connected in the same manner as the first winding body 31 and the second winding body 32.

[0055] In the following description, L is any integer greater than M. In this case, the third winding body 233 is a winding body with L layers wound in two aligned rows aligned in the radial direction. In this embodiment, the third winding body 233 is configured by stacking five layers of windings wound in aligned rows aligned in the radial direction. That is, in this embodiment, L is 5, and the third winding body 233 is a winding body with five layers wound in aligned rows aligned in the radial direction. As a result, the total number of turns of the third winding body 233 is 10.

[0056] The third winding body 233 has a pair of third axial extensions 233b extending in the axial direction on both circumferential sides of the tooth 22 to which the third winding body 233 is attached. The pair of third axial extensions 233b are disposed adjacent to the radially outer side of the pair of second axial extensions 32b. The contour shape of the third axial extensions 233b in a cross section perpendicular to the axial direction is, for example, a fan shape whose circumferential dimension decreases toward the radially inner side. More specifically, the contour shape of the third axial extensions 233b in a cross section perpendicular to the axial direction is a shape surrounded by two arcs and two line segments, similar to the above-mentioned axial extensions 30b.

[0057] In this embodiment, the cross-sectional shape of the part of the rectangular wire constituting the third winding body 233 that constitutes the third axial extension portion 233b is a trapezoid whose circumferential dimension decreases toward the radially inner side. More specifically, the cross-sectional shape of the part of the rectangular wire constituting the third winding body 233 that constitutes the third axial extension portion 233b is a trapezoid whose circumferential dimension decreases toward the radially inner side. In the following description, the part of the rectangular wire constituting the third winding body 233 that constitutes the third axial extension portion 233b is referred to as the third coil wire portion 233a.

[0058] Each of the pair of third axial extension parts 233b is configured by bundling a plurality of third coil wire parts 233a. In this embodiment, each third axial extension part 233b is configured by bundling ten third coil wire parts 233a. More specifically, in this embodiment, each third axial extension part 233b is configured by arranging five third coil wire parts 233a in the circumferential direction in two rows in the radial direction. The circumferential dimension in the cross section of the third coil wire part 233a constituting the radially outer row of the two rows arranged in the radial direction is larger than the circumferential dimension in the cross section of the third coil wire part 233a constituting the radially inner row. The circumferential dimension in the cross section of the third coil wire part 233a is smaller than the circumferential dimension in the cross section of the second coil wire part 32a.

[0059] The radial dimension in the cross section of the third coil wire portion 233a constituting the radially outer row is smaller than the radial dimension in the cross section of the third coil wire portion 233a constituting the radially inner row. The radial dimension in the cross section of the third coil wire portion 233a is larger than the radial dimension in the cross section of the second coil wire portion 32a. The cross-sectional areas of each of the third coil wire portions 233a are the same.

[0060] Although not shown in the drawings, the cross-sectional shape of the portion of the rectangular wire constituting the third winding body 233 other than the third axially extending portion 233b is, for example, a square shape with rounded corners. The other configurations of the coil 230 are similar to those of the coil 30 of the first embodiment.

[0061] According to this embodiment, since coil 230 is composed of three winding bodies, the total number of turns of coil 230 can be increased while precisely aligning the windings to prevent the shape of coil 230 from becoming distorted.

[0062] The present invention is not limited to the above-mentioned embodiment, and other configurations may be adopted within the scope of the technical concept of the present invention. N is not particularly limited as long as it is an integer of 1 or more. M is not particularly limited as long as it is an integer larger than N. L is not particularly limited as long as it is an integer larger than M. For example, N may be 1, M may be 2, and L may be 3. That is, the first winding body may be a winding body of one layer, the second winding body may be a winding body of two layers, and the third winding body may be a winding body of three layers. Also, M may be 2 or more larger than N, and L may be 2 or more larger than M. N, M, and L are preferably, for example, 10 or less. This is because it is easy to wind the rectangular wire to form each winding body and to compressively deform each winding body. Also, M is preferably, for example, 3 times or less than N. In this way, when compressively deforming the second winding body, it is possible to suppress the cross-sectional shape of the coil wire portion constituting the second axial extension portion from becoming more flat. The contour shape of the axially extending portion in a cross section perpendicular to the axial direction does not have to be a sector shape, and the cross-sectional shape of the coil wire portion constituting the axially extending portion does not have to be a trapezoid.

[0063] The step of compressively deforming the first winding body and the step of compressively deforming the second winding body may be performed after the step of connecting the first winding body and the second winding body. The steps of compressively deforming the first winding body and the second winding body do not necessarily have to be performed.

[0064] The motor to which the coil of the present invention is applied is not particularly limited. The motor to which the coil of the present invention is applied may be an outer rotor type motor. In this case, the radially outer side corresponds to one radial side, and the radially inner side corresponds to the other radial side. The configurations described in this specification above can be appropriately combined within a range that does not contradict each other.

Claims

1. A coil is attached to a tooth extending radially from an annular core back surrounding a central axis of a motor, A first winding body formed by winding a rectangular wire; A second winding body is configured by winding a rectangular wire, is located on the other radial side of the first winding body, and is connected to the first winding body; Equipped with When N is an integer equal to or greater than 1, and M is an integer greater than N, The first winding body is a winding body having N layers wound in line in two rows aligned in the radial direction, The second winding body is a winding body having M layers wound in two rows aligned in the radial direction, the first winding body has a pair of first axially extending portions extending in an axial direction of the central axis on both circumferential sides of the tooth, the second winding body has a pair of second axially extending portions extending in an axial direction of the central axis on both circumferential sides of the tooth, The pair of second axially extending portions are disposed adjacent to the pair of first axially extending portions on the other radial side thereof, the pair of first axially extending portions and the pair of second axially extending portions define a pair of axially extending portions extending in an axial direction of the central axis on both circumferential sides of the tooth, A contour shape of the axially extending portion in a cross section perpendicular to the axial direction of the central axis is a sector shape whose circumferential dimension decreases toward one radial side, A coil, wherein the radial dimension of a cross section of a second coil wire portion constituting the second axial extension portion of the flat wire constituting the second winding body is larger than the radial dimension of a cross section of a first coil wire portion constituting the first axial extension portion of the flat wire constituting the first winding body.

2. 2. The coil of claim 1, wherein in the first winding body, the radial dimension of a cross section of the one coil wire portion constituting a radially outer row is smaller than the radial dimension of a cross section of the first coil wire portion constituting a radially inner row.

3. The coil of claim 2 , wherein the cross-sectional areas of the first coil wire portions are the same as each other.

4. 2. The coil of claim 1, wherein in the second winding body, the radial dimension of a cross section of the two coil wire portions constituting a radially outer row is smaller than the radial dimension of a cross section of the second coil wire portion constituting a radially inner row.

5. The coil of claim 4 , wherein the cross-sectional areas of the second coil wire portions are the same as each other.

6. 2. The coil of claim 1, wherein the circumferential dimension of the cross section of the portion of the flat wire constituting the second winding body that constitutes the second axially extending portion is smaller than the circumferential dimension of the cross section of the portion of the flat wire constituting the first winding body that constitutes the first axially extending portion.

7. The coil as described in claim 1, wherein the cross-sectional shape of the flat wire constituting the first winding body and the second winding body other than the first axially extending portion and the second axially extending portion is a square with rounded corners.

8. The rotor further includes a third winding body that is configured by winding a rectangular wire, is located on the other radial side of the second winding body, and is connected to the second winding body.

2. The coil according to claim 1, wherein the third winding body is a winding body having L layers wound in regular order in two rows aligned in the radial direction, where L is an arbitrary integer greater than M.

9. A rotor rotatable about a central axis; a stator that faces the rotor in a radial direction with a gap therebetween; Equipped with The stator includes an annular core back surrounding the central axis, Teeth extending from the core back to one side in a radial direction; The coil according to any one of claims 1 to 8 attached to the teeth; A motor having

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