Motor and motor manufacturing method

Abstract

[Problem] To improve the space factor of a stator coil. [Solution] The present invention is configured so as to have a stator core 5 provided with a plurality of protrusions 18, and a plurality of coils 7 mounted to the plurality of protrusions 18 by using a concentrated winding method, wherein: each coil 7 is formed by winding a conducting wire W into a plurality of layers by aligned winding, and includes a slot part 20 housed in a slot 19 of the stator core 5, and a coil end part 21 disposed outside the slot 19; the arrangement of the conducting wire W in a cross section perpendicular to the wiring direction of the conducting wire W in the slot part 20 and the arrangement of the conducting wire W in a cross section at the coil end part 21 are different; and the outer shape of the cross section at the slot part 20 differs from the outer shape of the cross section at the coil end part 21.

Description

Motor and motor manufacturing method

[0001] The disclosed embodiments relate to a motor and a method for manufacturing a motor.

[0002] Patent Document 1 describes a rotating electric machine in which a coil wire is wound in an aligned manner around a bobbin attached to a stator core.

[0003] Japanese Patent Application Laid-Open No. 2014-230305

[0004] There is a demand for a motor that can improve the space factor of the stator coil.

[0005] The present invention has been made in view of the above problems, and has as its object to provide a motor and a motor manufacturing method that can improve the space factor of the stator coil.

[0006] In order to solve the above problems, according to one aspect of the present invention, a motor is provided which includes a stator core having a plurality of protrusions, and a plurality of coils attached to the plurality of protrusions using a concentrated winding method, the coils being formed by winding conductor wires in a plurality of layers using aligned winding, the motor having a slot portion housed in a slot of the stator core, and a coil end portion located outside the slot, the arrangement of the conductor wires in a cross section perpendicular to the wiring direction of the conductor wires in the slot portion being different from the arrangement of the conductor wires in the cross section in the coil end portion being different, and the outer shape of the cross section of the slot portion being different from the outer shape of the cross section of the coil end portion.

[0007] According to another aspect of the present invention, there is provided a motor comprising: a stator core having a plurality of protrusions; and a plurality of coils attached to the plurality of protrusions by a concentrated winding method, wherein the coils are formed by winding a conductor in a plurality of layers using aligned winding, and the motor comprises: a first coil section formed by winding a first conductor section from one end of the conductor to a predetermined intermediate position in a first winding direction starting from the predetermined intermediate position; and a second coil section formed by winding a second conductor section from the other end of the conductor to the predetermined intermediate position in a second winding direction opposite to the first winding direction starting from the predetermined intermediate position, wherein the one end and the other end of the conductor are drawn out from the outer circumferential layer of the coil, and the first coil section and the second coil section are adjacent to each other via a boundary section that is inclined with respect to a plane perpendicular to the axial direction of the coil.

[0008] According to another aspect of the present invention, there is provided a method for manufacturing a motor having a stator core with a plurality of protrusions and a plurality of coils attached to the plurality of protrusions using a concentrated winding method, the method comprising winding the conductors in a plurality of layers using aligned winding to form the coils so that the arrangement of the conductors in a cross section perpendicular to the wiring direction of the conductors in a slot portion accommodated in a slot of the stator core is different from the arrangement of the conductors in the cross section in a coil end portion located outside the slot, and so that the outer shape of the cross section of the slot portion is different from the outer shape of the cross section of the coil end portion.

[0009] According to another aspect of the present invention, there is provided a method for manufacturing a motor having a stator core with a plurality of protrusions and a plurality of coils attached to the plurality of protrusions using a concentrated winding method, the method comprising: winding a first conductor portion from one end of a conductor to a predetermined intermediate position in a plurality of layers using aligned winding in a first winding direction starting from the predetermined intermediate position to form a first coil portion; winding a second conductor portion from the other end of the conductor to the predetermined intermediate position in a second winding direction opposite to the first winding direction starting from the predetermined intermediate position in a plurality of layers using aligned winding, and winding the second conductor portion adjacent to the first coil portion with a boundary portion inclined with respect to a plane perpendicular to the axial direction of the coil; and drawing out the one end and the other end of the conductor from the layer on the outer periphery of the coil.

[0010] According to the motor etc. of the present invention, the space factor of the stator coil can be improved.

[0011] 1 is a longitudinal cross-sectional view showing an example of the overall configuration of a motor according to an embodiment; a transverse cross-sectional view corresponding to the II-II cross-section in FIG. 1; a plan view showing an example of a coil configuration as seen from the radial outside; a cross-sectional view showing an example of a cross-sectional shape perpendicular to the rotation axis of a slot portion of a coil according to Comparative Example 1; a cross-sectional view showing an example of a cross-sectional shape perpendicular to the rotation axis of a slot portion of a coil according to Comparative Example 2; a cross-sectional view showing an example of a cross-sectional shape perpendicular to the rotation axis of a slot portion of a coil according to the first embodiment; a cross-sectional view corresponding to the A-A cross-section in FIG. 3 showing an example of an outer shape of a cross section perpendicular to the wiring direction of the conductor wires and an example of an arrangement of the conductor wires in the slot portion of a coil according to the first embodiment; a cross-sectional view corresponding to the B-B cross-section in FIG. 3 showing an example of an outer shape of a cross section perpendicular to the wiring direction of the conductor wires and an example of an arrangement of the conductor wires in a coil end portion of a coil according to the first embodiment; a perspective view showing an example of the overall structure of a coil according to Comparative Example 3; a cross-sectional view corresponding to the C-C cross-section in FIG. 9 showing an example of a cross-sectional structure of a slot portion of a coil according to Comparative Example 3; a perspective view showing an example of the overall structure of a coil according to the second embodiment; a cross-sectional view corresponding to the D-D cross-section in FIG. 11 showing an example of a cross-sectional structure of a slot portion of a coil according to the second embodiment. 10A and 10B are cross-sectional views illustrating an example of the cross-sectional outer shape of a slot portion and a coil end portion of a coil according to a second embodiment and the arrangement of conductor wires; FIG. 10B are cross-sectional views illustrating an example of the cross-sectional outer shape of a slot portion of a coil according to a third embodiment and the arrangement of conductor wires, the cross-sectional views corresponding to the A-A section in FIG. 3; and FIG. 10C are cross-sectional views illustrating an example of the cross-sectional outer shape of a coil end portion of a coil according to a third embodiment and the arrangement of conductor wires, the cross-sectional views corresponding to the B-B section in FIG.

[0012] Hereinafter, embodiments will be described with reference to the drawings.

[0013] <1. Motor Configuration> First, the configuration of the motor 1 according to the embodiment will be described. The coils of the first to third embodiments, which will be described later, are mounted on the motor 1. FIG. 1 is a longitudinal cross-sectional view showing an example of the overall configuration of the motor 1 according to the embodiment, and FIG. 2 is a transverse cross-sectional view corresponding to the II-II cross section in FIG. 1. In the embodiment, the "load side" refers to the direction in which a load is attached to the motor 1, i.e., in the example of FIG. 1, the direction in which the shaft 10 protrudes (the right side in FIG. 1). The "anti-load side" refers to the opposite side from the load side, i.e., in FIG. 1, the direction in which the encoder 15 is disposed relative to the motor 1 (the left side in FIG. 1). In the embodiment, the "axial direction" refers to the direction along the rotational axis AX, the "circumferential direction" refers to the circumferential direction around the rotational axis AX, and the "radial direction" refers to the radial direction centered on the rotational axis AX.

[0014] As shown in FIG. 1 , the motor 1 is an inner rotor motor equipped with a stator 2 and a rotor 3, with the rotor 3 located inside the stator 2. The stator 2 includes a laminated core ring 30, a stator core 5, a bobbin 6, and a coil 7. The laminated core ring 30 is fixed to the inner circumferential surface of a frame 4, which is the housing of the motor 1. The stator core 5 is fixed to the inner circumferential surface of the laminated core ring 30. The coil 7 is attached to the stator core 5 via the bobbin 6. The bobbin 6 is made of an insulating material to electrically insulate the stator core 5 and the laminated core ring 30 from the coil 7. The coil 7 is an air-core coil formed by winding a conductor W in multiple layers using an aligned winding method. The conductor W is a round wire with a circular cross-section. Note that a rectangular wire with a rectangular cross-section may also be used as the conductor W. A substrate 8 is provided on the anti-load side (left side in FIG. 1 ) of the bobbin 6. The circuit provided on the substrate 8 and the winding start and end of the conductor W drawn out from the coil 7 are electrically connected by, for example, solder 9 or the like.

[0015] The rotor 3 is fixed to the outer periphery of the shaft 10 and is disposed on the inner periphery of the stator 2. The rotor 3 includes a rotor core 32 and a magnet 33 disposed on the outer periphery of the rotor core 32. The outer periphery of the magnet 33 is disposed so as to radially oppose the inner periphery of the stator core 5 via a predetermined gap G. Note that the magnet 33 is not limited to being disposed on the outer periphery of the rotor core 32, but may also be disposed inside the rotor core 32. The shaft 10 is rotatably supported about the rotation axis AX by a load-side bearing 12 having an outer ring fitted to a load-side bracket 11 disposed on the load side (right side in FIG. 1 ) of the frame 4, and a counter-load-side bearing 14 having an outer ring fitted to a counter-load-side bracket 13 disposed on the counter-load side (left side in FIG. 1 ) of the frame 4. An encoder 15 for detecting the rotational position or rotational speed of the rotor 3 is disposed on the counter-load-side end of the shaft 10. The encoder 15 is covered by an encoder cover 16. It should be noted that a resolver or the like may be provided instead of the encoder.

[0016] As shown in FIG. 2 , the stator core 5 has a plurality of (e.g., 12 in FIG. 2 ) protrusions 18 that protrude radially outward. The radially inner sides of the protrusions 18 are connected circumferentially to form a ring shape, and each protrusion 18 protrudes radially outward. A coil 7 is attached to each protrusion 18 from the outer periphery via a bobbin 6 using a concentrated winding method. In slots 19, which are spaces between two adjacent protrusions 18, opposing sides of the coils 7 attached to each protrusion 18 are arranged with a gap between them. The stator 2 is assembled by attaching a plurality of (e.g., 12 in FIG. 2 ) coils 7 to each protrusion 18 of the stator core 5 from the radially outer side via bobbins 6, and then fixing the stator core 5 to the inner periphery of an annular laminated core ring 30, which is then attached to the inner periphery of the frame 4. Resin is then pressed into the slots 19, and the bobbin 6, coils 7, etc. are molded with the resin.

[0017] Although the embodiment will be described with reference to a motor, the present invention may also be applied to a generator. Motors and generators are examples of rotating electrical machines.

[0018] 2. First Embodiment Next, a coil according to the first embodiment will be described. In the coil according to the first embodiment, the arrangement of the conductor wires in the slot portion of the coil is made different from the arrangement of the conductor wires in the coil end portion, thereby making the outer shape of the cross section of the slot portion different from the outer shape of the cross section of the coil end portion.

[0019] (2-1. Coil Configuration) The configuration of the coil 7 according to the first embodiment will be described with reference to Figures 3 to 8. Figure 3 is a plan view showing an example of the configuration of the coil 7 as seen from the radial outside. Figure 4 is a cross-sectional view showing an example of a cross-sectional shape perpendicular to the rotation axis AX of the slot portion 20A of the coil 7A according to Comparative Example 1. Figure 5 is a cross-sectional view showing an example of a cross-sectional shape perpendicular to the rotation axis AX of the slot portion 20B of the coil 7B according to Comparative Example 2. Figure 6 is a cross-sectional view showing an example of a cross-sectional shape perpendicular to the rotation axis AX of the slot portion 20 of the coil 7 according to the first embodiment. Figure 7 is a cross-sectional view corresponding to the A-A cross-section in Figure 3 showing an example of the outer shape of a cross-section perpendicular to the wiring direction of the conductor wires W in the slot portion 20 of the coil 7 according to the first embodiment and an example of the arrangement of the conductor wires W. Figure 8 is a cross-sectional view corresponding to the B-B cross-section in Figure 3 showing an example of the outer shape of a cross-section perpendicular to the wiring direction of the conductor wires W in the coil end portion 21 of the coil 7 according to the first embodiment and an example of the arrangement of the conductor wires W.

[0020] As shown in Figure 3, the coil 7 has a pair of slot portions 20 accommodated in the slots 19 of the stator core 5, and a pair of coil end portions 21 located outside the slots 19. The two slot portions 20 are arranged opposite each other in the circumferential direction, and the two coil end portions 21 are arranged opposite each other in the axial direction. The coil 7 is formed as an air-core coil having an air-core portion S, which is a hollow space, by winding a conductor W in multiple layers in an aligned manner around a winding jig (not shown). The coil 7 is attached to the protrusions 18 of the stator core 5 from the radial outside via a bobbin 6. The protrusions 18 and the bobbin 6 are inserted into the air-core portion S.

[0021] Fig. 4 shows an example of the cross-sectional shape of the slot portion 20A of the coil 7A according to Comparative Example 1. The coil 7A is configured so that the cross-sectional arrangement and outer shape of the slot portion 20A are substantially the same as the cross-sectional arrangement and outer shape of the coil end portion 21A. As shown in Fig. 4, in Comparative Example 1, the coil 7A is formed so that the cross-sectional outer shape of the slot portion 20A reaches near the inner circumferential tip of the protrusion 18 of the stator core 5. In this case, as shown in Fig. 4, the cross-sectional outer shape of the coil end portion 21A protrudes radially inward from the inner circumferential surface 5a of the stator core 5, which may cause interference with the gap G between the stator 2 and the rotor 3.

[0022] FIG. 5 shows an example of the cross-sectional shape of the slot portion 20B of the coil 7B according to Comparative Example 2. Similar to the coil 7A according to Comparative Example 1, the coil 7B is configured so that the cross-sectional arrangement and outer shape of the slot portion 20B are substantially the same as the cross-sectional arrangement and outer shape of the coil end portion 21B. As shown in FIG. 5 , in Comparative Example 2, in order to prevent the cross-sectional outer shape of the coil end portion 21B from protruding radially inward from the inner circumferential surface 5a of the stator core 5, the coil 7B is formed so that the cross-sectional outer shape of the slot portion 20B does not reach the inner circumferential tip of the protrusion 18. In this case, as shown in FIG. 5 , a dead space DS where the coil 7B is not disposed may be generated in the slot 19 near the inner circumferential tip of the protrusion 18, resulting in a decrease in the space factor of the slot 19.

[0023] FIG. 6 shows an example of the cross-sectional shape of the slot portion 20 of the coil 7 according to the first embodiment. The coil 7 is configured such that the arrangement of the conductor wires W in the slot portion 20 differs from the arrangement of the conductor wires W in the coil end portion 21, thereby making the cross-sectional outer shape of the slot portion 20 different from the cross-sectional outer shape of the coil end portion 21. Specifically, as shown in FIG. 6 , the coil 7 is configured such that the radially inner surface 21a of the coil end portion 21 is located radially outward of a line L connecting a portion 20a1 of one slot portion 20 closest to the rotation axis AX and a portion 20a2 of the other slot portion 20 closest to the rotation axis AX. The coil 7 is also configured such that the shortest radial distance D between the coil end portion 21 and the rotation axis AX is greater than the radial distance R between the inner circumferential surface 5a of the stator core 5 and the rotation axis AX. Note that the shortest distance D and the distance R may be substantially equal. The distance R is the inner diameter of the stator core 5. Furthermore, the coil 7 is configured so that at least a portion of the straight line L is located radially inward of the inner circumferential surface 5 a of the stator core 5 .

[0024] 7 and 8 show an example of the cross-sectional outline of the slot portion 20 and the coil end portion 21 of the coil 7 and the arrangement of the conductor wire W. In addition, in Fig. 7 and Fig. 8, the numbers inside each conductor wire W indicate an example of the winding order of the regular winding.

[0025] 7 and 8, the arrangement of the conductors W in the slot portions 20 and the arrangement of the conductors W in the coil end portions 21 are partially common to each other and differ from each other in other portions. In Figures 7 and 8, the conductors W shown in white are conductors that are arranged in the same manner in the slot portions 20 and the coil end portions 21, and the conductors W shown with diagonal hatching are conductors that are arranged differently in the slot portions 20 and the coil end portions 21. As shown in Figures 7 and 8, the conductors W that are arranged differently are arranged near the end on the rotation axis AX side.

[0026] Specifically, as shown in FIG. 7 , in the slot portion 20, the conductor wire W starts winding at the top end of the first layer, which is the innermost layer in the radial direction of the coil, in the axial direction (No. 1), and is wound sequentially downward from the top end (Nos. 1 to 7). When it reaches the bottom end of the first layer (No. 7), it moves from the bottom end of the second layer outside the first layer to the second position (No. 8) and continues winding upward (Nos. 8 to 13). When it reaches the top end of the second layer (No. 13), it moves to the top end of the third layer outside the second layer (No. 14) and continues winding downward (Nos. 14 to 19). When it reaches the second position from the bottom end of the third layer (No. 19), it moves from the second position from the bottom end of the fourth layer outside the third layer (No. 20) and continues winding upward (Nos. 20 to 24). When the wire reaches the top of the fourth layer (No. 24), it moves to the top of the fifth layer, which is the outermost layer (No. 25), and continues winding downward (Nos. 25 to 29). When the wire reaches the second position from the bottom of the fifth layer (No. 29), it moves to the bottom of the second layer (No. 30), then the bottom of the third layer (No. 31), then the bottom of the fourth layer (No. 32), and finally the bottom of the fifth layer (No. 33), completing the winding. As a result of winding the wire W in the above-described arrangement, the cross-sectional outer shape OL1 of the slot portion 20 is substantially pentagonal, with a vertex projecting downward in the coil axis direction, i.e., radially inward of the motor 1.

[0027] 8 , in the coil end portion 21, the conductor wire W is wound in the same manner as in the slot portion 20 from positions 1 to 29. When it reaches the third position from the bottom of the fifth layer (position 29), it moves to the bottom position of the third layer (position 30), then to the bottom position of the fourth layer (position 31), then to the second position from the bottom of the fifth layer (position 32), and finally to the bottom position of the fifth layer (position 33), where it ends. As a result of winding the conductor wire W in the above-described arrangement, the outer shape OL2 of the cross section of the coil end portion 21 is a substantially rectangular shape with substantially flat upper and lower sides in the coil axis direction.

[0028] In this way, the coil 7 is formed by winding the conductor W in multiple layers by aligned winding so that the arrangement of the conductor W in a cross section perpendicular to the wiring direction of the conductor W in the slot portions 20 housed in the slots 19 of the stator core 5 is different from the arrangement of the conductor W in a cross section in the coil end portions 21 located outside the slots 19, and so that the outer shape of the cross section of the slot portions 20 is different from the outer shape of the cross section of the coil end portions 21. The procedure for forming the coil 7 is an example of a motor manufacturing method.

[0029] The number of turns and the winding order of the conductor W described above are merely examples, and other arrangements may be used. For example, the arrangement of the conductor W in the slot portion 20 may be different from the arrangement of the conductor W in the coil end portion 21 in a region other than the end portion on the rotation axis AX side, or may be different not only in a partial region but also in the entire region in the cross section.

[0030] (2-2. Effects of the First Embodiment) According to the first embodiment described above, by differentiating the cross-sectional outer shape OL1 of the slot portion 20 of the coil 7 from the cross-sectional outer shape OL2 of the coil end portion 21, the cross-sectional outer shape OL1 of the slot portion 20 can be shaped to reach the inner circumferential tip of the protrusion 18 of the stator core 5, while the cross-sectional outer shape OL2 of the coil end portion 21 can be shaped so as not to protrude radially inward from the inner circumferential surface 5a of the stator core 5. This makes it possible to improve the space factor of the stator coil while preventing interference with the gap G of the stator coil. Furthermore, because the cross-sectional shape is changed by differentiating the arrangement of the conductor wire W between the slot portion 20 and the coil end portion 21, the outer shapes of the two can be made different without pressure molding or the like. As a result, it is possible to simplify the manufacturing process and reduce manufacturing costs.

[0031] Furthermore, in the present embodiment, the coil 7 may be configured such that, when viewed in a cross section perpendicular to the rotation axis AX, the radially inner surface 21a of the coil end portion 21 is located radially outward of a straight line L connecting a portion 20a1 of one slot portion 20 closest to the rotation axis AX and a portion 20a2 of the other slot portion 20 closest to the rotation axis AX. This allows the conductor W to be arranged up to the inner circumferential tip of the protrusion 18 in the slot portion 20, while the conductor W in the coil end portion 21 can be arranged so as not to protrude radially inward from the inner circumferential surface 5a of the stator core 5.

[0032] Furthermore, in this embodiment, the coil 7 may be configured so that the shortest radial distance D between the coil end portion 21 and the rotation axis AX is greater than the radial distance R between the inner circumferential surface 5a of the stator core 5 and the rotation axis AX. This allows the coil end portion 21 to be positioned radially outward of the inner circumferential surface 5a of the stator core 5. This prevents the coil end portion 21 from interfering with the gap G.

[0033] Furthermore, in this embodiment, when viewed in a cross section perpendicular to the rotation axis AX, the coil 7 may be configured such that at least a part of a straight line L connecting a portion 20a1 of one slot portion 20 closest to the rotation axis AX and a portion 20a2 of the other slot portion 20 closest to the rotation axis AX is located radially inward of the inner circumferential surface 5a of the stator core 5. This allows the conductor W to be positioned as close as possible to the inner circumferential tip of the protrusion 18 in the slot portion 20, while preventing interference with the gap G of the coil end portion 21.

[0034] In this embodiment, the coil 7 may be configured such that the arrangement of the slots 20 and the arrangement of the coil end portions 21 are partially the same and partially different from each other. This makes it easier to wind the conductor W than when the arrangements of the slots 20 and the coil end portions 21 are entirely different.

[0035] Furthermore, in this embodiment, the coil 7 may be configured such that the portions of the slot portions 20 and the coil end portions 21 where the arrangement differs are located near the end portion on the rotation axis AX side. This allows the shapes of the inner peripheral sides of the slot portions 20 and the coil end portions 21 of the coil 7 to be different. For example, it is possible to form the inner peripheral surface of the coil end portions 21 in a shape that is curved radially outward more than the inner peripheral surface of the slot portions 20.

[0036] 3. Second Embodiment Next, a coil according to a second embodiment will be described. The coil according to the second embodiment is formed by a winding method in which both ends of the coil are pulled out from the outer periphery of the coil (so-called alpha winding).

[0037] (3-1. Coil Configuration) The configuration of the coil 22 according to the second embodiment will be described with reference to FIGS. 9 to 13. FIG. 9 is a perspective view illustrating an example of the overall structure of the coil 22A according to Comparative Example 3. FIG. 10 is a cross-sectional view corresponding to the cross-section C-C in FIG. 9 illustrating an example of the cross-sectional structure of the slot portion 23A of the coil 22A according to Comparative Example 3. FIG. 11 is a perspective view illustrating an example of the overall structure of the coil 22 according to the second embodiment. FIG. 12 is a cross-sectional view corresponding to the cross-section D-D in FIG. 11 illustrating an example of the cross-sectional structure of the slot portion 23 of the coil 22 according to the second embodiment. FIG. 13 is a cross-sectional view illustrating an example of the outline of a cross section perpendicular to the wiring direction of the conductor W and the arrangement of the conductor W in the slot portion 23 and the coil end portion 24 of the coil 22 according to the second embodiment. Note that FIGS. 9 to 12 illustrate the number of turns and the number of layers of the conductor W in a simplified manner.

[0038] 9 and 10 show an example of the overall structure of a coil 22A and the cross-sectional structure of a slot portion 23A according to Comparative Example 3. The coil 22A is configured so that the cross-sectional arrangement and outer shape of the slot portion 23A are substantially the same as the cross-sectional arrangement and outer shape of the coil end portion 24A. As shown in FIGS. 9 and 10 , the coil 22A of Comparative Example 3 starts winding the conductor wire W from the inner periphery and pulls it out from the outer periphery, so the winding start end WS of the conductor wire W is located on the inner periphery. Therefore, pulling the winding start end WS outward creates dead spaces DS1 and DS2, for example, as shown in FIG. 10 , which reduces the space factor. Furthermore, for example, if a relief groove is formed in the bobbin 6, this hinders the improvement of the space factor within the slot 19.

[0039] 11 and 12 show an example of the overall structure of the coil 22 and the cross-sectional structure of the slot portions 23 according to the second embodiment. The coil 22 is configured so that the cross-sectional arrangement and outer shape of the slot portions 23 are substantially the same as the cross-sectional arrangement and outer shape of the coil end portions 24. As shown in FIGS. 11 and 12 , the coil 22 has a first coil portion 22a and a second coil portion 22b. The first coil portion 22a is formed by winding a conductor W (an example of a first conductor portion) from one end WE1 of the conductor W to an intermediate position WM (an example of a predetermined intermediate position) in a winding direction WD1 (an example of a first winding direction) starting from the intermediate position WM. The second coil portion 22b is formed by winding the conductor W (an example of a second conductor portion) from the other end WE2 of the conductor W to an intermediate position WM in a winding direction WD2 (an example of a second winding direction) opposite to the winding direction WD1, starting from the intermediate position WM. The first coil portion 22a and the second coil portion 22b are continuously connected at the intermediate position WM to form a single conductor W. The one end WE1 and the other end WE2 of the conductor W are drawn out from the outermost layer of the coil 22. Note that, for ease of understanding, in FIG. 11 , the first coil portion 22a is illustrated in white and the second coil portion 22b is illustrated with dotted hatching. In FIG. 12 , the first coil portion 22a is illustrated with wide diagonal hatching and the second coil portion 22b is illustrated with narrow diagonal hatching.

[0040] With the above configuration, both ends WE1 and WE2 of the coil 22 can be pulled out from the outer periphery of the coil 22. This reduces dead space and eliminates the need for a relief groove or the like in the bobbin 6, thereby improving the space factor of the stator coil.

[0041] Fig. 13 shows an example of the outer shape and arrangement of the conductor wire W in the slot portion 23 and coil end portion 24 of the coil 22. In Fig. 13, the numbers inside each conductor wire W indicate an example of the winding order of regular winding, with numbers without a sign indicating the winding order of the first coil portion 22a and numbers with a negative sign indicating the winding order of the second coil portion 22b.

[0042] As shown in FIG. 13 , the first coil portion 22a of the conductor W starts winding at the top end of the first layer, which is the innermost layer in the radial direction of the coil (No. 1), in the winding direction WD1, and is wound sequentially downward from the top end (Nos. 1 to 7). When it reaches the bottom end of the first layer (No. 7), it moves to the bottom end of the second layer outside the first layer (No. 8) and continues winding upward (Nos. 8 to 13). When it reaches the second position from the top end of the second layer (No. 13), it moves from the top end of the third layer outside the second layer to the third position (No. 14) and continues winding downward (Nos. 14 to 18). When it reaches the bottom end of the third layer (No. 18), it moves to the bottom end of the fourth layer outside the third layer (No. 19) and continues winding upward (Nos. 19 to 22). When it reaches the third position from the top of the fourth layer (No. 22), it moves to the fourth position from the top of the fifth layer, which is the outermost layer (No. 23), and continues to be wound downward (Nos. 23 to 25). When it reaches the bottom of the fifth layer, it finishes winding (No. 25) and is pulled out as one end WE1.

[0043] The second coil portion 22b of the conductor W starts winding at the top end of the first layer, the innermost layer in the radial direction (No. 1), and continues winding in a winding direction WD2 opposite to the winding direction WD1, moving to the top end of the second layer (No. -1), then moving to the second position from the top of the third layer (No. -2), and continuing upward (Nos. -2 to -3). When it reaches the top of the third layer (No. -3), it moves to the top of the fourth layer (No. -4), and continues downward (Nos. -4 to -5). When it reaches the second position from the top of the fourth layer (No. -5), it moves to the third position from the top of the fifth layer (No. -6), and continues upward (Nos. -6 to -8). When it reaches the top of the fifth layer, it ends winding (No. -8), and is drawn out as the other end WE2.

[0044] As a result of winding the conductor W in the above-described arrangement, the cross-sectional outer shape OL3 of the slot portion 23 and the coil end portion 24 is approximately pentagonal in shape with a vertex protruding downward in the coil axis direction, i.e., radially inward of the motor 1.

[0045] 13 , the first coil portion 22a and the second coil portion 22b are arranged adjacent to each other via a boundary portion BP that is inclined with respect to a plane HP perpendicular to the axial direction of the coils. The first coil portion 22a and the second coil portion 22b are also arranged such that an uneven portion 25 (an example of a first uneven portion) formed by the arrangement of the conductor wires W of the first coil portion 22a and an uneven portion 26 (an example of a second uneven portion) formed by the arrangement of the conductor wires W of the second coil portion 22b fit together at the boundary portion BP. The uneven portions 25, 26 are formed by bulges due to the circular shape of each conductor wire W and depressions due to gaps between adjacent conductor wires W, and the uneven portion 25 of the first coil portion 22a and the uneven portion 26 of the second coil portion 22b fit together by being alternately interlocked. 13. At least a part of the first coil portion 22a, for example, the conductors W of the first and second coil portions 22b and 22c in FIG. 13, is disposed between the second coil portion 22b and the air core portion S.

[0046] In this manner, the first coil portion 22a is formed by winding the portion of the conductor W from one end WE1 to a predetermined intermediate position WM in a winding direction WD1 in multiple layers starting from the predetermined intermediate position WM, while the second coil portion 22b is formed by winding the portion of the conductor W from the other end WE2 to the predetermined intermediate position WM in a winding direction WD2 opposite to the winding direction WD1 in multiple layers starting from the predetermined intermediate position WM, with the second coil portion 22b adjacent to the first coil portion 22a across a boundary BP that is inclined with respect to a plane perpendicular to the axial direction of the coil 22. The coil 22 is formed by drawing out the end WE1 and the end WE2 of the conductor W from the outer layer of the coil 22. This procedure for forming the coil 22 is an example of a motor manufacturing method.

[0047] The number of turns and winding order of the conductor W described above are merely examples, and other arrangements may be used. For example, the ratio of the second coil portion 22b in the arrangement of the conductor W in the cross sections of the slot portion 23 and the coil end portion 24 may be further increased or further decreased.

[0048] (3-2. Effects of the Second Embodiment) According to the second embodiment described above, both end portions WE1, WE2 of the coil 22 can be pulled out from the outer periphery of the coil 22. This reduces dead space and eliminates the need for a relief groove or the like in the bobbin 6, thereby improving the space factor of the stator coil. Furthermore, since the first coil portion 22a and the second coil portion 22b are adjacent to each other with a slanted boundary portion BP therebetween, unnecessary gaps between the first coil portion 22a and the second coil portion 22b can be prevented, improving the space factor, and slanting the boundary portion BP can prevent the winding from collapsing during the winding operation, making the winding operation easier.

[0049] In this embodiment, the coil 22 may be configured such that the uneven portion 25 formed by the arrangement of the conductor wires W of the first coil portion 22a and the uneven portion 26 formed by the arrangement of the conductor wires W of the second coil portion 22b fit together at the boundary portion BP. This further reduces the gap between the first coil portion 22a and the second coil portion 22b, thereby improving the space factor. In addition, the fit between the uneven portions prevents the winding from becoming unbalanced during the winding process, making the winding process easier.

[0050] In this embodiment, the coil 22 may be configured such that at least a portion of the first coil portion 22a is interposed between the second coil portion 22b and the air-core portion S. This allows the second coil portion 22b to be wound so as to ride on the outer layer of the first coil portion 22a, making the winding process easier.

[0051] 4. Third Embodiment Next, a coil according to a third embodiment will be described. The coil according to the third embodiment differs between the arrangement of the conductor wires in the slot portion of the coil and the arrangement of the conductor wires in the coil end portion, thereby making the cross-sectional outer shape of the slot portion different from the cross-sectional outer shape of the coil end portion, and is formed using a winding method in which both ends of the coil are pulled out from the outer periphery of the coil (so-called alpha winding). In other words, the third embodiment is an embodiment that has features of both the first and second embodiments described above.

[0052] (4-1. Coil Configuration) The coil 27 according to the third embodiment is an air-core coil with an air-core portion S, which has a pair of slots 28 and a pair of coil end portions 29, similar to the coils 7 and 22 described above. The coil 27 has the same configuration as that shown in FIG. 6 described above. That is, as shown in FIG. 6, the coil 27 is configured such that the radially inner surface 29a of the coil end portion 29 is located radially outward of a line L connecting a portion 28a1 of one slot 28 closest to the rotation axis AX and a portion 28a2 of the other slot 28 closest to the rotation axis AX. The coil 27 is also configured such that the shortest radial distance D between the coil end portion 29 and the rotation axis AX is greater than the radial distance R between the inner circumferential surface 5a of the stator core 5 and the rotation axis AX. Note that the shortest distance D and the distance R may be equal. Furthermore, the coil 27 is configured so that at least a portion of the straight line L is located radially inward of the inner circumferential surface 5 a of the stator core 5 .

[0053] The coil 27 has the same configuration as that shown in FIGS. 11 and 12 . That is, as shown in FIGS. 11 and 12 , the coil 27 has a first coil portion 27 a and a second coil portion 27 b. The first coil portion 27 a is formed by winding the conductor W from one end WE1 of the conductor W to an intermediate position WM in a winding direction WD1 starting from the intermediate position WM. The second coil portion 27 b is formed by winding the conductor W from the other end WE2 of the conductor W to the intermediate position WM in a winding direction WD2 starting from the intermediate position WM. The first coil portion 27 a and the second coil portion 27 b are continuously connected at the intermediate position WM to form a single conductor W. The one end WE1 and the other end WE2 of the conductor W are drawn out from the outermost layer of the coil 27.

[0054] 14 and 15 show an example of the outer shape and arrangement of the conductor wires W in the slot portions 28 and coil end portions 29 of the coil 27 according to the third embodiment. Fig. 14 is a cross-sectional view corresponding to the A-A section in Fig. 3 , illustrating an example of the outer shape and arrangement of the conductor wires W in a cross section perpendicular to the wiring direction of the conductor wires W in the slot portions 28 of the coil 27 according to the third embodiment. Fig. 15 is a cross-sectional view corresponding to the B-B section in Fig. 3 , illustrating an example of the outer shape and arrangement of the conductor wires W in a cross section perpendicular to the wiring direction of the conductor wires W in the coil end portions 29 of the coil 27 according to the third embodiment. Note that in Figs. 14 and 15 , the numbers inside each conductor wire W indicate an example of the winding order of regular winding, with numbers without a sign indicating the winding order of the first coil portion 27a and numbers with a negative sign indicating the winding order of the second coil portion 27b.

[0055] 14 and 15, the arrangement of the conductors W in the slots 28 and the arrangement of the conductors W in the coil end portions 29 are partially common to each other and differ in other portions. In Figures 14 and 15, the conductors W shown in white are conductors that are arranged in the same manner in the slots 28 and the coil end portions 29, and the conductors W shown with diagonal hatching are conductors that are arranged differently in the slots 28 and the coil end portions 29. As shown in Figures 14 and 15, the conductors W that are arranged differently are arranged near the end on the rotation axis AX side.

[0056] As shown in FIG. 14 , in the slot portion 28, the first coil portion 27a of the conductor wire W starts winding at the top end of the first layer, which is the innermost layer in the coil radial direction (No. 1), in the winding direction WD1, and is wound sequentially downward from the top end (Nos. 1 to 7). When it reaches the bottom end of the first layer (No. 7), it moves to the second position from the bottom end of the second layer outside the first layer (No. 8) and continues winding upward (Nos. 8 to 12). When it reaches the second position from the top end of the second layer (No. 12), it moves to the third position from the top end of the third layer outside the second layer (No. 13) and continues winding downward (Nos. 13 to 16). When it reaches the second position from the bottom end of the third layer (No. 16), it moves to the second position from the bottom end of the fourth layer outside the third layer (No. 17) and continues winding upward (Nos. 17 to 19). When it reaches the third position from the top of the fourth layer (No. 19), it moves to the fourth position from the top of the fifth layer, which is the outermost layer (No. 20), and continues winding downward (Nos. 20 to 21). When it reaches the second position from the bottom of the fifth layer (No. 21), it moves to the bottom of the second layer (No. 22), then the bottom of the third layer (No. 23), then the bottom of the fourth layer (No. 24), and finally the bottom of the fifth layer, where it finishes winding (No. 25) and is pulled out as one end WE1.

[0057] The second coil portion 27b of the conductor W starts winding at the top end of the first layer, the innermost layer in the radial direction (No. 1), and continues winding in a winding direction WD2 opposite to the winding direction WD1, moving to the top end of the second layer (No. -1), then moving to the second position from the top of the third layer (No. -2), and continuing upward (Nos. -2 to -3). When it reaches the top of the third layer (No. -3), it moves to the top of the fourth layer (No. -4), and continues downward (Nos. -4 to -5). When it reaches the second position from the top of the fourth layer (No. -5), it moves to the third position from the top of the fifth layer (No. -6), and continues upward (Nos. -6 to -8). When it reaches the top of the fifth layer, it ends winding (No. -8), and is drawn out as the other end WE2.

[0058] As a result of winding the conductor W in the above-described arrangement, the cross-sectional outer shape OL4 of the slot portion 28 is approximately pentagonal in shape with a vertex protruding downward in the coil axis direction, i.e., radially inward of the motor 1.

[0059] As shown in FIG. 15 , in the coil end portion 29, the first coil portion 27a of the conductor W is wound in the same manner as in the slot portion 28 from slots 1 to 21. When it reaches the third position from the bottom of the fifth layer (21), it moves to the bottom position of the third layer (22), then the bottom position of the fourth layer (23), then the second position from the bottom of the fifth layer (24), and finally reaches the bottom position of the fifth layer (25), where the winding ends. The second coil portion 27b of the conductor W is wound in the same manner as in the slot portion 28 from slots −1 to −8. As a result of winding the conductor W in the above-described arrangement, the outer shape OL5 of the cross section of the coil end portion 29 is a substantially rectangular shape with substantially flat upper and lower sides in the coil axis direction.

[0060] 14 and 15 , the first coil portion 27a and the second coil portion 27b are arranged adjacent to each other via a boundary portion BP that is inclined with respect to a plane HP perpendicular to the axial direction of the coils. The first coil portion 27a and the second coil portion 27b are arranged such that an uneven portion 34 (an example of a first uneven portion) formed by the arrangement of the conductor wires W of the first coil portion 27a and an uneven portion 35 (an example of a second uneven portion) formed by the arrangement of the conductor wires W of the second coil portion 27b fit together at the boundary portion BP. Furthermore, at least a portion of the first coil portion 27a, such as the conductor wires W numbered 1 and 2 in FIGS. 14 and 15 , is arranged between the second coil portion 27b and the air-core portion S.

[0061] In this manner, the first coil portion 27a is formed by winding the portion of the conductor W from one end WE1 to a predetermined intermediate position WM in a winding direction WD1 in multiple layers starting from the predetermined intermediate position WM, while the second coil portion 27b is formed by winding the portion of the conductor W from the other end WE2 to the predetermined intermediate position WM in a winding direction WD2 opposite to the winding direction WD1 in multiple layers starting from the predetermined intermediate position WM, with the second coil portion 27b adjacent to the first coil portion 27a across a boundary BP that is inclined with respect to a plane perpendicular to the axial direction of the coil 27. The coil 27 is formed by drawing out the end WE1 and the end WE2 of the conductor W from the outer layer of the coil 27. This procedure for forming the coil 27 is an example of a motor manufacturing method.

[0062] The number of turns and winding order of the conductor W described above are merely examples, and other arrangements may be used. For example, the arrangement of the conductor W in the slot portion 28 may be different from the arrangement of the conductor W in the coil end portion 29 in a region other than the end portion on the rotation axis AX side, or may be different not only in a partial region but also in the entire region of the cross section. Furthermore, for example, the proportion of the second coil portion 27b in the arrangement of the conductor W in the cross section of the slot portion 28 and the coil end portion 29 may be further increased or further decreased.

[0063] (4-2. Effects of the Third Embodiment) According to the third embodiment described above, it is possible to obtain both the effects of the first embodiment and the effects of the second embodiment.

[0064] 5. Modifications The disclosed embodiments are not limited to those described above, and various modifications are possible within the scope of the spirit and technical concept thereof.

[0065] For example, the coils 7, 22, and 27 may be press-molded to form a predetermined shape by plastically deforming the conductor wire W by the pressure. The predetermined shape may be, for example, a shape corresponding to the slot 19 or the bobbin 6. This can further reduce the gaps between the conductor wires W, thereby further increasing the space factor.

[0066] In addition, in the embodiment, although the cross-sectional shape of the boundary portion BP is shown to be approximately linear in Figures 13 to 15, the cross-sectional shape of the boundary portion BP is not limited to an approximately linear shape, and may be, for example, a stepped shape with steps, or a jagged shape in which a straight line is bent multiple times.

[0067] In the above description, when terms such as "vertical," "parallel," and "plane" are used, these terms are not used in their strict sense. These terms "vertical," "parallel," and "plane" mean "substantially vertical," "substantially parallel," and "substantially plane," allowing for tolerances and errors in design and manufacturing.

[0068] In the above description, when the external dimensions, size, shape, position, etc. are described as "same," "equal," "different," etc., these descriptions do not have the strict meaning. The terms "same," "equal," and "different" mean "substantially the same," "substantially the same," "substantially equal," and "substantially different," allowing for design and manufacturing tolerances and errors.

[0069] In addition to what has already been described above, the methods according to the above-described embodiments and modifications may be combined as appropriate. Although not specifically illustrated, the above-described embodiments and modifications may be modified in various ways within the spirit and scope of the invention.

[0070] The problems and effects that the above-described embodiments and modifications are intended to solve are not limited to those described above. The embodiments and modifications may solve problems or achieve effects that are not described above, or may solve only some of the problems or achieve only some of the effects that are described.

[0071] REFERENCE SIGNS LIST 1 motor 2 stator 3 rotor 5 stator core 5a inner peripheral surface 6 bobbin 7 coil 18 protrusion 19 slot 20 slot portion 20a1 closest portion 20a2 closest portion 21 coil end portion 21a surface 22 coil 22a first coil portion 22b second coil portion 23 slot portion 24 coil end portion 25 uneven portion 26 uneven portion 27 coil 27a first coil portion 27b second coil portion 28 slot portion 28a1 closest portion 28a2 closest portion 29 coil end portion 29a surface 34 uneven portion 35 uneven portion AX rotation axis BP boundary portion D shortest distance DS dead space DS1 dead space DS2 dead space G gap HP Surface L Straight line OL1 Outline OL2 Outline OL3 Outline OL4 Outline OL5 Outline R Distance S Air core W Conductor WD1 Winding direction WD2 Winding direction WE1 End WE2 End WM Middle position

Claims

1. A motor comprising: a stator core having a plurality of protrusions; and a plurality of coils attached to the plurality of protrusions using a concentrated winding method, wherein the coils are formed by winding a conductor in a plurality of layers using aligned winding, and have a slot portion received in a slot of the stator core; and a coil end portion located outside the slot, wherein an arrangement of the conductors in a cross section perpendicular to the wiring direction of the conductors in the slot portion differs from an arrangement of the conductors in the cross section at the coil end portion, and wherein an outer shape of the cross section of the slot portion differs from an outer shape of the cross section of the coil end portion.

2. The motor as described in claim 1, wherein the motor has a rotor that rotates around a rotational axis, the coil has a pair of slot portions arranged opposite each other in the circumferential direction around the rotational axis, and when viewed in a cross section perpendicular to the rotational axis, the radially inner surface of the coil end portion is configured to be located radially outward of a straight line connecting a portion of the slot portion on one side closest to the rotational axis and a portion of the slot portion on the other side closest to the rotational axis.

3. The motor described in claim 2, wherein the coil is configured so that the shortest radial distance between the coil end portion and the rotational shaft center is greater than the radial distance between the inner surface of the stator core and the rotational shaft center.

4. A motor as described in claim 3, wherein, when viewed in a cross section perpendicular to the rotation axis, at least a part of a straight line connecting a portion of one slot portion closest to the rotation axis and a portion of the other slot portion closest to the rotation axis is configured to be located radially inward relative to the inner surface of the stator core.

5. A motor as claimed in any one of claims 1 to 4, wherein the coil is configured so that the arrangement of the slot portions and the arrangement of the coil end portions are common to each other in some parts and differ from each other in other parts other than the certain parts.

6. The motor according to claim 5, wherein the motor has a rotor that rotates around a rotation axis, and the coils are configured such that, in the arrangement of the slot portions and the arrangement of the coil end portions, the other portions are positioned near the end on the rotation axis side.

7. The motor described in claim 1, wherein the coil has a first coil section formed by winding a first conductor section from one end of the conductor to a predetermined intermediate position in a first winding direction starting from the predetermined intermediate position, and a second coil section formed by winding a second conductor section from the other end of the conductor to the predetermined intermediate position in a second winding direction opposite to the first winding direction, starting from the predetermined intermediate position, wherein the one end and the other end of the conductor are pulled out from the layer on the outer periphery of the coil, and the first coil section and the second coil section are configured to be adjacent to each other via a boundary section that is inclined with respect to a plane perpendicular to the axial direction of the coil.

8. The motor according to claim 7, wherein the coil is configured such that a first uneven portion formed by the arrangement of the conductor wires of the first coil section and a second uneven portion formed by the arrangement of the conductor wires of the second coil section fit together at the boundary portion.

9. The motor according to claim 7 or 8, wherein the coil is an air-core coil, and at least a portion of either one of the first coil portion or the second coil portion is interposed between the air-core portion and the coil portion of the other coil portion.

10. A motor as claimed in claim 1 or 7, wherein the conductor is a round wire, and the coil is formed into a shape corresponding to the slot by plastic deformation of the conductor by applying pressure.

11. A motor comprising: a stator core having a plurality of protrusions; and a plurality of coils attached to the plurality of protrusions using a concentrated winding method, wherein the coils are formed by winding a conductor in a plurality of layers using aligned winding, and comprising: a first coil section formed by winding a first conductor section from one end of the conductor to a predetermined intermediate position in a first winding direction starting from the predetermined intermediate position; and a second coil section formed by winding a second conductor section from the other end of the conductor to the predetermined intermediate position in a second winding direction opposite to the first winding direction, starting from the predetermined intermediate position; the one end and the other end of the conductor are pulled out from the layer on the outer periphery of the coil, and the first coil section and the second coil section are configured to be adjacent to each other via a boundary section that is inclined with respect to a plane perpendicular to the axial direction of the coil.

12. A method for manufacturing a motor having a stator core having a plurality of protrusions, and a plurality of coils attached to the plurality of protrusions using a concentrated winding method, comprising winding the conductors in a plurality of layers by aligned winding to form the coils, such that an arrangement of the conductors in a cross section perpendicular to the wiring direction of the conductors in a slot portion accommodated in a slot of the stator core is different from an arrangement of the conductors in the cross section at a coil end portion placed outside the slot, and such that an outer shape of the cross section of the slot portion is different from an outer shape of the cross section of the coil end portion.

13. A method for manufacturing a motor having a stator core with a plurality of protrusions and a plurality of coils attached to the plurality of protrusions using a concentrated winding method, the method comprising: winding a first conductor portion from one end of a conductor to a predetermined intermediate position in a first winding direction starting from the predetermined intermediate position into a plurality of layers using aligned winding to form a first coil portion; winding a second conductor portion from the other end of the conductor to the predetermined intermediate position in a second winding direction opposite to the first winding direction starting from the predetermined intermediate position into a plurality of layers using aligned winding, and winding the second conductor portion adjacent to the first coil portion via a boundary portion that is inclined with respect to a plane perpendicular to the axial direction of the coil, to form a second coil portion; and drawing out the one end and the other end of the conductor from the layer on the outer periphery of the coil.

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