Method for manufacturing an armature, armature and core

Abstract

A method of manufacturing an armature including a core (20) and a coil (30) is provided. The core (20) includes slots (21). The coil (30) is mounted to the slots (21). Each slot (21) includes a constant portion (21A) and an enlarged portion (21B) disposed radially outward of the constant portion (21A). The method includes a disposing step of disposing conductors (40) in a row within each slot (21) across the constant portion (21A) and the enlarged portion (21B). The conductors (40) are included in the coil (30) and each have an outer surface covered by an insulating covering. The method further includes a first pressing step of pressing and plastically deforming the conductors (40) disposed in a row within each slot (21) in the disposing step using a first pressing jig (60). A width of the first pressing jig (60) is equal to a width of the constant portion (21A). In the first pressing step, the first pressing jig (60) is moved within a range of the constant portion (21A) of the slot (21) to plastically deform the conductors (40) disposed in a row.

Description

Technical Field

[0001] The present disclosure relates to a method for manufacturing an armature. The present disclosure also relates to an armature and an iron core. Background Art

[0002] Japanese Patent Application Laid-Open No. 2002-125338 discloses a method for manufacturing a stator used as an armature. The stator is part of an AC generator. The stator includes an iron core and a stator coil. The iron core includes slots. The stator coil is mounted in the slots of the iron core. In the method for manufacturing a stator disclosed in this document, the conductor of the stator coil is bent and deformed into a predetermined shape in advance, and a portion of the deformed conductor is arranged in each slot of the iron core. Then, the conductor is pressurized in each slot to plastically deform the cross-sectional shape of the conductor. This reduces the gap between the conductor and the slot, thereby increasing the space factor of the stator coil in the slot.

[0003] Japanese Patent Application Laid-Open No. 2015-082952 discloses a stator including an iron core with slots. The iron core includes teeth spaced at regular intervals in the circumferential direction. The circumferentially opposite side surfaces of the teeth are parallel to each other. The slots between the teeth are shaped so that their circumferential width increases radially outward.

[0004] When the method for manufacturing a stator disclosed in Japanese Patent Laid-Open No. 2002-125338 is applied to the stator disclosed in Japanese Patent Laid-Open No. 2015-082952, the following problems may arise.

[0005] like Figure 14 As shown, when the circumferential width of the slot 100 increases radially outward, the width of the pressurizing jig 120 for pressurizing the conductor 110 disposed in the slot 100 is made smaller than the width of the slot 100 so that the pressurizing jig 120 can move.

[0006] Therefore, if Figure 15 As shown, the press jig 120 plastically deforms the conductor 110 so as to bite into the conductor 110. As a result, the conductor 110 is formed to have a C-shaped cross section, which includes a main body 111, a first piece 112 and a second piece 113. The main body 111 is circumferentially ( Figure 15 The first piece 112 and the second piece 113 are formed to protrude radially inward from opposite ends of the main body 111.

[0007] like Figure 16 As shown, in this state, a new conductor 140 is placed in the slot 100, and the conductor 140 is pressurized using the pressurizing jig 120. In this case, as shown in FIG. Figure 16As shown by the arrow in FIG. 1, the newly arranged conductors 140 are plastically deformed so as to press the first and second pieces 112 and 113 against the side surfaces of the teeth 130. This can generate excessive compression forces acting on the first and second pieces 112 and 113, and can damage the insulating cover covering the outer surfaces of the conductors 110. This problem is not disclosed in the above-described patent document. Thus, there is room for improvement. SUMMARY

[0008] An object of the present disclosure is to provide a method for manufacturing an armature, an armature, and a core, which can ensure insulation of a coil arranged in a slot shaped so that a width in a circumferential direction increases toward an outer side in a radial direction, while improving a space factor of the coil.

[0009] This summary is provided to introduce a selection of concepts that are further described below in the detailed description. This summary is neither intended to nor should it be taken to be used to limit the claims in any fashion. This summary is provided to introduce a selection of concepts that are further described below in the detailed description. This summary is neither intended to nor should it be taken to be used to limit the claims in any fashion.

[0010] A method for manufacturing an armature that solves the above-described problem is provided. The armature includes a core and coils. The core includes slots. The coils are mounted to the slots. Each slot includes a constant portion and an enlarged portion. The constant portion has a constant width in a circumferential direction. The enlarged portion is arranged radially outward of the constant portion and is shaped so that the width increases toward an outer side in a radial direction. The method includes an arranging step of arranging conductors in a row across the constant portion and the enlarged portion in each slot. The conductors are included in the coils and each have an outer surface covered by an insulating cover. The method further includes a first pressing step of pressing and plastically deforming the conductors arranged in a row in each slot in the arranging step using a first pressing jig. A width of the first pressing jig is equal to the width of the constant portion. In the first pressing step, the first pressing jig is moved within a range of the constant portion of the slot to plastically deform the conductors arranged in a row.

[0011] An armature that solves the above-described problem is provided. The armature includes a core and coils. The core includes slots. The coils are mounted to the slots. Each slot includes a constant portion and an enlarged portion. The constant portion has a constant width in a circumferential direction. The enlarged portion is arranged radially outward of the constant portion and is shaped so that the width increases toward an outer side in a radial direction. The coils include arranged portions arranged in the slots and coil ends arranged outside the slots, respectively. Each arranged portion is formed by a conductor. The conductors are included in the coils and each have an outer surface covered by an insulating cover. The conductors are arranged in a row across the constant portion and the enlarged portion of a corresponding one of the slots. Adjacent ones of the conductors of the arranged portions each include a contact surface. The contact surfaces of the adjacent conductors are in contact with each other. The widths of the contact surfaces in the circumferential direction are equal to each other. Opposite surfaces of the conductors opposite to inner circumferential surfaces of the corresponding one of the slots are in close contact with the inner circumferential surfaces.

[0012] A core that solves the above problems is provided. The core includes a ring-shaped back yoke and teeth that project radially inward from the back yoke. The core includes grooves each defined by a side surface in the circumferential direction of the teeth and an inner peripheral surface portion of the back yoke. Each groove includes a constant portion and an enlarged portion. The constant portion has a constant width in the circumferential direction. The enlarged portion is disposed radially outward of the constant portion and is shaped such that the width increases toward the radially outward side.

[0013] Other features and aspects will become apparent from the following detailed description, drawings and claims. BRIEF DESCRIPTION OF DRAWINGS

[0014] Figure 1 is a perspective view of a stator.

[0015] Figure 2 is an enlarged sectional view showing the structure of a portion of the stator.

[0016] Figure 3 is a perspective view showing a conductor mounted to a stator core.

[0017] Figure 4 is a sectional view showing the conductor disposed in a groove in a first disposition step.

[0018] Figure 5 is a sectional view showing a first pressing jig disposed in the groove.

[0019] Figure 6 is a sectional view showing the conductor plastically deformed using the first pressing jig.

[0020] Figure 7 is a sectional view showing the conductor disposed in the groove in a second disposition step.

[0021] Figure 8 is a sectional view showing a second pressing jig disposed in the groove.

[0022] Figure 9 is a sectional view showing the conductor plastically deformed using the second pressing jig.

[0023] Figure 10 is a plan view showing the shape of a groove of a stator core.

[0024] Figure 11 is a graph showing an example of the relationship between a boundary position and an output torque.

[0025] Figure 12 is a plan view showing the shape of a groove of a stator core of a deformation example.

[0026] Figure 13 is a plan view showing the shape of a groove of a stator core of another deformation example.

[0027] Figure 14 is a plan view showing a conductor and a press jig configured in a slot of a stator core in a stator having a conventional structure.

[0028] Figure 15 is a plan view showing a conductor and a press jig configured in a slot of a stator core in a stator having a conventional structure. Figure 14 is a sectional view of a conductor plastically deformed by the press jig of the conventional structure shown in

[0029] Figure 16 is a plan view showing a conductor and a press jig configured in a slot of a stator core in a stator having a conventional structure. Figure 14 and Figure 15 is a plan view showing a conductor and a press jig configured in a slot of a stator core in a stator having a conventional structure.

[0030] Throughout the drawings and specific embodiments, identical reference numerals indicate identical elements. The drawings can not be to scale and the dimensions, proportions, and shapes of the elements in the drawings can be exaggerated for clarity, illustration, and convenience. DETAILED DESCRIPTION

[0031] The present detailed description provides a comprehensive understanding of the described methods, apparatus, and / or systems. Variations and equivalents of the described methods, apparatus, and / or systems will be apparent to those skilled in the art. The sequence of operations is exemplary, and can be changed as will be obvious to those skilled in the art, except operations that must be performed in a particular order. Descriptions of functions and constructions known to those skilled in the art can be omitted.

[0032] The exemplary embodiments can have different forms and are not limited to the described examples. However, the described examples are thorough and complete, and convey the full scope of the disclosure to those skilled in the art.

[0033] In this specification, "at least one of A and B" is understood to mean "only A, only B, or both A and B".

[0034] A stator according to an embodiment will now be described with reference to Figures 1 to 13 A stator according to an embodiment will now be described with reference to

[0035] As shown in Figure 1 The stator 10 includes a stator core 20 serving as an iron core and a stator coil 30 mounted to the stator core 20. The stator core 20 is substantially cylindrical. The stator core 20 is formed by, for example, laminating thin and ring-shaped electrical steel sheets.

[0036] As shown in Figure 2As shown, the stator core 20 includes slots 21. The slots 21 include back yokes 22 and teeth 23. The back yokes 22 are annular. The teeth 23 each project inwardly from an inner circumferential surface portion 22A of the back yoke 22 in a radial direction (hereinafter, simply referred to as a radial direction) of the stator core 20. The teeth 23 are spaced apart from each other in a circumferential direction. The inner circumferential surface portion 22A of the back yoke 22 and the side surface 24 in the circumferential direction of the teeth 23 define the slot 21.

[0037] The side surface 24 in the circumferential direction of the tooth 23 includes a parallel portion 24A and an inclined portion 24B. The parallel portion 24A extends in the radial direction. More specifically, the parallel portion 24A of each tooth 23 extends along a first imaginary line L1 that passes through a middle portion of an adjacent tooth 23. The parallel portion 24A of each tooth 23 is parallel to the side surface 24 (more specifically, the parallel portion 24A) of the opposite tooth 23. Thus, the distance between the opposite parallel portions 24A is constant. The parallel portion 24A of the side surface 24 defines a constant portion 21A of the slot 21. That is, the constant portion 21A of the slot 21 has a constant width in the circumferential direction.

[0038] The inclined portion 24B is located radially outward of the parallel portion 24A. The inclined portion 24B of each tooth 23 is inclined with respect to the first imaginary line L1 such that the inclined portion 24B becomes distanced from the side surface 24 (more specifically, the inclined portion 24B) of the opposite tooth 23 toward the radially outward side. Thus, the distance between the opposite inclined portions 24B becomes longer toward the radially outward side. The inclined portion 24B of the side surface 24 of the tooth 23 and the inner circumferential surface portion 22A of the back yoke 22 define an enlarged portion 21B of the slot 21. That is, the enlarged portion 21B of the slot 21 is shaped such that the width in the circumferential direction increases toward the radially outward side.

[0039] Each tooth 23 includes an opening protrusion 24C. The opening protrusion 24C is located radially inward of the parallel portion 24A in the side surface 24. The opening protrusion 24C of each tooth 23 is shaped to project from the corresponding parallel portion 24A toward the opposite tooth 23. Thus, the distance between the opposite opening protrusions 24C is shorter than the distance between the opposite parallel portions 24A. The opening protrusion 24C of the side surface 24 defines an opening 21C of the slot 21. That is, the opening 21C of the slot 21 has a width in the circumferential direction that is smaller than that of the constant portion 21A.

[0040] Thus, each slot 21 extends in the radial direction and includes, in order from the radially inward side, the opening 21C, the constant portion 21A, and the enlarged portion 21B.

[0041] As Figure 1 and Figure 2As shown, the stator coil 30 includes a placement portion 31 disposed within each slot 21 and a coil end 32 disposed outside the slot 21. The stator coil 30 includes three stator coils 30 corresponding to a U-phase coil, a V-phase coil, and a W-phase coil. The U-phase coil, the V-phase coil, and the W-phase coil have substantially the same structure. Therefore, these coils will now be collectively described as stator coils 30 without distinguishing them.

[0042] like Figure 3 As shown, the stator coil 30 includes a conductor 40. In this embodiment, the conductor 40 is a square wire with a rectangular cross section. The conductor 40 may be a square wire with a polygonal cross section other than a rectangular cross section, or may be a circular wire with a circular cross section. The conductor 40 is made of a metal such as aluminum. The outer surface of the conductor 40 is covered with an insulating layer. The conductor 40 includes two straight portions 41 extending in parallel and a base end ( Figure 3 Each straight portion 41 extends from the distal end ( Figure 3 The conductor 40 is inserted through the corresponding slot 21. The base end of the straight portion 41 is disposed within the slot 21. The distal end of the straight portion 41 is disposed outside the slot 21. The conductor 40 includes an inner portion 50 disposed within the slot 21 and an outer portion 51 located outside the slot 21. Specifically, the inner portion 50 is defined by the base end of the straight portion 41, and the outer portion 51 is defined by the distal end or curved portion 42 of the straight portion 41.

[0043] like Figure 2 As shown, eight straight sections 41 of conductors 40 are radially arranged in each slot 21. The two straight sections 41 of a conductor 40 are each inserted through a different slot 21. Each conductor 40 is attached to the stator core 20 and then formed into a desired shape through, for example, a pressing and bending step. Subsequently, the distal end of the straight section 41 of one conductor 40 is joined to the distal end of the straight section 41 of another conductor 40. As a result, the conductors 40 are connected to one another, forming the stator coil 30 wound around the stator core 20.

[0044] A detailed description will now be given of a method for manufacturing the stator 10. In the present embodiment, the conductor 40 is installed inside each slot 21 by sequentially performing a first arranging step, a first pressurizing step, a second arranging step, and a second pressurizing step.

[0045] like Figure 4As shown, in the first arrangement step, the conductors 40 are arranged in a row across the constant portion 21A and the expanded portion 21B of the slot 21. In this embodiment, seven conductors 40 are arranged in the slot 21 from the side where the expanded portion 21B is located. Hereinafter, the conductors 40 are referred to as the first conductor 40A, the second conductor 40B, the third conductor 40C, the fourth conductor 40D, the fifth conductor 40E, the sixth conductor 40F, and the seventh conductor 40G, starting from the back yoke 22. The first conductor 40A to the third conductor 40C are arranged in the expanded portion 21B of the slot 21. The fourth conductor 40D is arranged in the portion of the slot 21 that extends from the expanded portion 21B to the constant portion 21A. The fifth conductor 40E to the seventh conductor 40G are arranged in the constant portion 21A of the slot 21.

[0046] Then, if Figure 5 As shown, in the first pressurizing step, the first pressurizing jig 60 is arranged in the constant portion 21A of the groove 21. The first pressurizing jig 60 includes a pressurizing portion 60A and a driving portion 60B installed on the pressurizing portion 60A. The pressurizing portion 60A is arranged between the conductor 40 and the opening 21C in the constant portion 21A. The driving portion 60B extends radially inward through the opening 21C. The circumferential width of the pressurizing portion 60A is equal to the width of the constant portion 21A. The situation where the width of the pressurizing portion 60A is equal to the width of the constant portion 21A not only refers to the situation where the widths are completely equal to each other, but also refers to the situation where the width of the pressurizing portion 60A is slightly smaller than the width of the constant portion 21A. In the latter case, a gap is generated so that the pressurizing portion 60A can be installed inside the constant portion 21A and the pressurizing portion 60A can move radially in the constant portion 21A.

[0047] like Figure 6As shown, in the first pressurizing step, after configuring the first pressurizing jig 60, the driving portion 60B is moved radially outward so that the pressurizing portion 60A pressurizes the seventh conductor 40G radially outward. The moving distance D1 of the first pressurizing jig 60 is pre-set so that the pressurizing portion 60A falls within the range D2 of the constant portion 21A. The first pressurizing jig 60 is used to pressurize the conductor 40 toward the back yoke 22 so that the cross-sectional shape of the inner portion 50 is plastically deformed according to the shape of the slot 21. Each inner portion 50 is squeezed so that the width of its cross section becomes equal to the width of the slot 21. As a result, the inner portion 50 is deformed into the shape of a thin plate. The conductors 40 are plastically deformed while in contact with each other. Therefore, when the width of each conductor 40 increases to be equal to the width of the slot 21, the contact surface of the conductor 40 is uniformly deformed. For example, the first contact surface S1 of the first conductor 40A, which contacts the second conductor 40B, is deformed so that the width of the first contact surface S1 remains equal to the width of the second contact surface S2 of the second conductor 40B, which contacts the first conductor 40A. Furthermore, the third contact surface S3 of the second conductor 40B, which contacts the third conductor 40C, is deformed so that the width of the third contact surface S3 remains equal to the width of the fourth contact surface S4 of the third conductor 40C, which contacts the second conductor 40B. Thus, adjacent conductors 40 among the conductors 40 each include a contact surface, and the contact surfaces of the adjacent conductors 40 are in contact with each other. Furthermore, the circumferential widths of the contact surfaces are equal. The term "equal" refers not only to situations where the widths are completely equal, but also to situations where the widths differ slightly due to changes in the amount of elastic deformation during pressurization.

[0048] The first conductor 40A includes an opposing surface ( Figure 6 The left surface in the middle), the opposite surface ( Figure 6 ) and an opposite surface ( Figure 6 After the conductor 40 is pressurized in the first pressurizing step, these opposing surfaces are in close contact with the inner peripheral surface of the slot 21. In addition, the remaining conductors 40 except the first conductor 40A, that is, the second conductor 40B to the seventh conductor 40G, each include an opposing surface ( Figure 6 ) and an opposite surface ( Figure 6 These opposing surfaces are in close contact with the inner circumferential surface of the groove 21.

[0049] After the first pressurizing step is performed to plastically deform the first to seventh conductors 40A to 40G in this manner, the second arranging step is performed.

[0050] like Figure 7As shown, in the second placement step, a new conductor 40 is placed in the gap in the slot 21 created by plastically deforming the conductor 40 in the first pressurizing step. In this embodiment, one conductor 40 is placed as the new conductor 40. Hereinafter, the newly placed conductor 40 is referred to as the eighth conductor 40H. The eighth conductor 40H is placed between the seventh conductor 40G and the opening 21C of the slot 21.

[0051] Then, if Figure 8 As shown, in the second pressurizing step, the second pressurizing jig 61 is positioned within the opening 21C of the groove 21. The circumferential width of the second pressurizing jig 61 is smaller than the width of the constant portion 21A and is equal to the width of the opening 21C. The fact that the width of the second pressurizing jig 61 is equal to the width of the opening 21C of the groove 21 not only refers to a case where the widths are completely equal, but also to a case where the width of the second pressurizing jig 61 is slightly smaller than the width of the opening 21C. In the latter case, a gap is created, allowing the second pressurizing jig 61 to be installed within the opening 21C and to move radially within the opening 21C.

[0052] like Figure 9 As shown, in the second pressurizing step, a second pressurizing jig 61 is deployed and then moved radially outward to pressurize the eighth conductor 40H radially outward. Because the first to seventh conductors 40A to 40G, already plastically deformed in the first pressurizing step, resist deformation due to strain hardening, the inner portion 50 of the newly deployed eighth conductor 40H is plastically deformed. The inner portion 50 of the eighth conductor 40H is compressed, causing the cross-sectional width of the inner portion 50 to become equal to the width of the constant portion 21A. As a result, the inner portion 50 is deformed. Because the width of the second pressurizing jig 61 is smaller than the width of the constant portion 21A, the second pressurizing jig 61 plastically deforms the eighth conductor 40H by biting into it. As a result, the cross-sectional shape of the eighth conductor 40H is plastically deformed to a C-shape comprising a main body 40H1, a first piece 40H2, and a second piece 40H3. The main body 40H1 is in the shape of a thin plate and extends circumferentially. The first piece 40H2 and the second piece 40H3 are formed to protrude radially inward from opposite ends of the main body 40H1 .

[0053] The seventh conductor 40G includes a fifth contact surface S5 that contacts the eighth conductor 40H, and the eighth conductor 40H includes a sixth contact surface S6 that contacts the seventh conductor 40G. After the eighth conductor 40H is pressurized in the second pressurization step, the fifth contact surface S5 has the same width as the sixth contact surface S6. Thus, the seventh conductor 40G and the eighth conductor 40H both include contact surfaces, and the contact surfaces of adjacent conductors 40 are in contact with each other. In addition, the circumferential widths of the contact surfaces are equal to each other. The eighth conductor 40H includes an opposing surface ( Figure 9 ) and an opposite surface ( Figure 9 These opposing surfaces are in close contact with the inner circumferential surface of the groove 21.

[0054] After the conductors 40 are installed inside the slots 21 by sequentially performing the first arrangement step, the first pressurizing step, the second arrangement step, and the second pressurizing step in this manner, a bending step is performed to bend the outer side portions 51 of the conductors 40 in the radial and circumferential directions. Subsequently, the straight portion 41 of each conductor 40 is joined to the straight portion 41 of another conductor 40. As a result, the stator coil 30 wound around the stator core 20 is formed using the conductors 40 that are continuous with each other.

[0055] like Figure 1 and Figure 2 As shown, in the stator coil 30, the inner portion 50 of the conductor 40 forms the arrangement portion 31 arranged within the slot 21, and the outer portion 51 of the conductor 40 forms the coil end 32 arranged outside the slot 21. As described above, the arrangement portion 31 is formed by the conductors 40 arranged in a row across the constant portion 21A and the expanded portion 21B of the slot 21. Among the conductors 40 in the arrangement portion 31, adjacent ones of the conductors 40 each include a contact surface, and the contact surfaces of adjacent conductors 40 are in contact with each other. Furthermore, the circumferential widths of the contact surfaces are equal. The opposing surface of the conductor 40, which faces the inner circumferential surface of the slot 21, is in close contact with the inner circumferential surface.

[0056] A rotor including permanent magnets is arranged on the inner peripheral side of the stator 10. This forms a rotating electrical machine such as a motor or a generator. When forming a motor, for example, the rotor is rotated by performing energization control on the stator coil 30 of the stator 10.

[0057] In this embodiment, the shape of the groove 21 is set as follows.

[0058] like Figure 10The side surface 24 of each tooth 23 includes a parallel portion 24A extending along the first imaginary line L1 and an inclined portion 24B extending obliquely with respect to the first imaginary line L1, as indicated by a solid line in FIG. 6. The inclined portion 24B of each tooth 23 has an inclination angle Θ with respect to the first imaginary line L1. The inclination angle Θ is set to an angle at which the inclined portion 24B is parallel to a second imaginary line L2 extending in the radial direction through the center of the tooth 23 at the angle. As indicated by a dashed line in FIG. 6, in the case where the two side surfaces 24 of the tooth 23 are parallel to each other (i.e., in the case where the tooth 23 is a parallel tooth), the second imaginary line L2 is parallel to the side surface 24i. In the present embodiment, a boundary between the parallel portion 24A and the inclined portion 24B, i.e., a boundary position Pi between the constant portion 21A and the enlarged portion 21B of the groove 21 is located near the middle in the radial direction of the groove 21. Figure 10 As indicated by a dashed line in FIG. 6, in the case where the two side surfaces 24 of the tooth 23 are parallel to each other (i.e., in the case where the tooth 23 is a parallel tooth), the second imaginary line L2 is parallel to the side surface 24i. In the present embodiment, a boundary between the parallel portion 24A and the inclined portion 24B, i.e., a boundary position Pi between the constant portion 21A and the enlarged portion 21B of the groove 21 is located near the middle in the radial direction of the groove 21.

[0059] In Figure 10 In the first comparative example, the parallel portion 24A is set to be longer than that of the present embodiment and extends to the outer side in the radial direction. That is, a boundary position P2 between the constant portion 21A and the enlarged portion 21B of the groove 21 of the first comparative example is located on the outer side in the radial direction of the boundary position Pi of the present embodiment. The inclined portion 24B of the first comparative example extends parallel to the second imaginary line L2.

[0060] In Figure 10 In the second comparative example, the parallel portion 24A is set to be shorter than that of the present embodiment. That is, a boundary position P3 between the constant portion 21A and the enlarged portion 21B of the groove 21 of the second comparative example is located on the inner side in the radial direction of the boundary position Pi of the present embodiment. The inclined portion 24B of the second comparative example extends parallel to the second imaginary line L2.

[0061] When the boundary position between the constant portion 21A and the enlarged portion 21B of the groove 21 is changed while the inclination angle Θ of the inclined portion 24B is maintained in this manner, the output torque changes in the case where the stator 10 of the electric motor is used. Figure 11 This change is shown.

[0062] More specifically, in the case where the boundary position is located on the radially inner side and close to the opening 21C as in the second comparative example, the enlarged portion 21B of the slot 21 has an increased volume, and thus the space factor of the enlarged portion 21B is improved. However, the width of the tooth 23 is narrow, and thus the output torque is small. From this state, as the boundary position moves radially outward, that is, as the distance between the boundary position and the opening 21C becomes longer, the improvement effect of the output torque due to the increase in the width of the tooth 23 is greater than the decrease effect of the output torque due to the decrease in the space factor. Thus, the output torque increases. In contrast, as the boundary position moves radially outward from the predetermined position Pa (for example, to the boundary position P2 in the first comparative example), the improvement effect of the output torque due to the increase in the width of the tooth 23 is smaller than the decrease effect of the output torque due to the decrease in the space factor. Thus, the output torque decreases. This indicates that the output torque tends to be the greatest when the boundary position is located at the predetermined position Pa, and the farther the boundary position is from the predetermined position Pa, the lower the output torque tends to be. In the present embodiment, the length of the parallel portion 24A is obtained and set in advance so that the boundary position P1 is located at the predetermined position Pa at which the output torque is the greatest.

[0063] The effects and advantages of the present embodiment will now be described.

[0064] (1) In the present embodiment, the slots 21 formed in the stator core 20 each include a constant portion 21A and an enlarged portion 21B. The constant portion 21A has a constant width in the circumferential direction. The enlarged portion 21B is located on the radially outer side of the constant portion 21A and is shaped so that the width increases toward the radially outer side. The conductors 40 are included in the stator coil 30, and the outer surfaces of the respective conductors 40 are covered with an insulating cover. A first arrangement step is performed to arrange the conductors 40 in a row across the constant portion 21A and the enlarged portion 21B within the slot 21. Then, a first pressing step is performed to press and plastically deform the conductors 40 arranged in the row in the first arrangement step using a first pressing jig 60 having the same width as the constant portion 21A. In the first pressing step, the first pressing jig 60 is moved within the range of the constant portion 21A of the slot 21 to plastically deform the conductors 40 arranged in the row.

[0065] The first press jig 60 moves within the range of the constant portion 21A and has the same width as the constant portion 21A. This limits the case where the first press jig 60 bites into the conductor 40 being pressed in the constant portion 21A. In the enlarged portion 21B, the conductors 40 are plastically deformed in contact with each other. Thus, when the width of each conductor 40 increases to be equal to the width of the slot 21, the contact surfaces of the conductors 40 are uniformly deformed. This keeps the width of the contact surfaces of the conductors 40 equal to each other during plastic deformation and limits the case where one conductor 40 bites into another conductor 40. Thus, the case where the conductor 40 is bitten by another conductor 40 or the first press jig 60 is limited. This prevents an excessive compression force from acting on a part of the conductor 40. Therefore, even if the conductors 40 are plastically deformed in close contact with the inner circumferential surface of the slot 21, damage to the insulating cover on the outer surface of the conductor 40 is prevented. In addition, the conductors 40 are in contact with the inner circumferential surface of the slot 21. This ensures the insulation of the stator coil 30 arranged in the slot 21 shaped so that the width in the circumferential direction increases toward the outside, while improving the space factor of the stator coil 30.

[0066] (2) The present embodiment further includes a second arrangement step and a second pressing step. In the second arrangement step, a new conductor 40 is arranged in the constant portion 21A of the slot 21 after the first pressing step is performed. In the second pressing step, the conductor 40 arranged in the second arrangement step is pressed and plastically deformed using a second press jig 61 having a width smaller than the constant portion 21A. In the second pressing step, the eighth conductor 40H located at the radially innermost position in the constant portion 21A is pressed radially outward using the second press jig 61. This plastically deforms the cross-sectional shape of the eighth conductor 40H into a C shape.

[0067] In the second pressing step, when the eighth conductor 40H located at the radially innermost position in the constant portion 21A is shaped to have a C-shaped cross-section, the eighth conductor 40H has a shape that is concave radially outward compared to a structure in which the eighth conductor 40H is shaped to have a rectangular cross-section rather than a C-shaped cross-section. Thus, when a rotor is mounted to the inner circumferential side of the stator 10 to form a rotary electric machine, the distance between the permanent magnet of the rotor and the eighth conductor 40H becomes longer. This reduces eddy currents generated in the eighth conductor 40H due to rotation of the rotor. Therefore, forming a rotary electric machine by using such a stator 10 contributes to reducing eddy current loss in the rotary electric machine.

[0068] (3) In the present embodiment, the shape of the slot 21 is set so that the boundary position P1 between the constant portion 21A and the enlarged portion 21B of the slot 21 is located at the same position as a predetermined position Pa at which the output torque is the largest. This contributes to increasing the torque in the rotary electric machine and reducing the size of the rotary electric machine.

[0069] The present embodiment can be modified as follows. The present embodiment and the following modified examples can be combined as long as they are technically consistent with each other.

[0070] In the above embodiment, eight conductors 40 are installed inside each slot 21. The number of conductors 40 can be changed. Further, the number of conductors 40 arranged in the first arrangement step is not limited to seven and can be changed as long as the conductors 40 can be arranged in a row across the constant portion 21A and the enlarged portion 21B inside the slot 21. Even in this structure, the first pressing step allows the conductors 40 arranged inside the enlarged portion 21B of the slot 21 to be deformed in accordance with the shape of the enlarged portion 21B while ensuring the insulation of the stator coil 30. Further, the number of conductors 40 arranged in the second arrangement step is not limited to one and can be two or more as long as the conductors 40 can be arranged inside the constant portion 21A of the slot 21. Even in this structure, by pressing the conductor 40 located at the radially innermost position using the second pressing jig 61, the conductor 40 can be deformed to have a C-shaped cross section.

[0071] In the second pressing step, the eighth conductor 40H is plastically deformed to have a C-shaped cross section. This structure can be omitted. For example, the eighth conductor 40H can be plastically deformed to have a rectangular cross section. This structure can be obtained by arranging a pressing jig having the same width as the constant portion 21A between the eighth conductor 40H and the opening 21C and pressing it between the eighth conductor 40H and the opening 21C.

[0072] In the above embodiment, the side surface 24 of the tooth 23 is arranged with the opening protrusion 24C, and the slot 21 is arranged with the opening 21C having a smaller width than the constant portion 21A. Alternatively, a structure in which the side surface 24 of the tooth 23 is not arranged with the opening protrusion 24C can be employed.

[0073] In the above embodiment, the boundary position P1 between the constant portion 21A and the enlarged portion 21B of the slot 21 is set to be located at the same position as the predetermined position Pa at which the output torque is the largest. The boundary position P1 is not necessarily set in this way. For example, the boundary position P1 can be set to a position different from the predetermined position Pa, such as the boundary position P2 of the first comparative example or the boundary position P3 of the second comparative example. Thus, the stator core 20 includes a stator core having a slot 21 shaped as shown in the first comparative example and the second comparative example. That is, even in the case of using the stator core 20 having a slot 21 shaped as shown in the first comparative example and the second comparative example, the same effects and advantages as (1) are obtained.

[0074] In the above-described embodiment, the inclination angle θ of the inclined portion 24B is set to be parallel to the second imaginary line L2. Instead, the inclination angle θ of the inclined portion 24B can be inclined with respect to the second imaginary line L2. Even in this structure, when the enlarged portion 21B is located on the radially outer side of the constant portion 21A and is shaped such that the width increases toward the radially outer side, the same effects and advantages as (1) are obtained. In addition, the inclined portion 24B is not necessarily straight in a plan view. For example, as shown in Figure 12 one inclined portion 24B can be shaped to have a curve that protrudes inward, so that the inclined portion 24B becomes farther from the opposite inclined portion 24B toward the radially outer side. Instead, as shown in Figure 13 one inclined portion 24B can be shaped to have a curve that protrudes outward, so that the distance from the opposite inclined portion 24B becomes smaller toward the radially outer side.

[0075] As an example of the armature, the stator 10 including the stator core 20 and the stator coil 30 is described. The armature is not limited to the stator 10. For example, the armature can be a rotor including a rotor core having the slots 21 and a rotor coil installed to the slots 21 of the rotor core, and the armature can have the same structure as the above-described embodiment.

[0076] Various changes can be made to the above examples without departing from the spirit and scope of the claims and their equivalents. The above examples are merely illustrative, and are not to be taken as limiting the present disclosure in any way. The description of features or aspects within each example should be taken as being applicable to similar features or aspects in other examples unless incompatible. Suitable results can be achieved if the described arrangements are performed in a different order, and / or if components are used in combination with, or in place of, other components or their equivalents. Nothing in the present disclosure is to be taken as an admission that the present disclosure is not entitled to antedate this disclosure by virtue of prior application. The scope of the present disclosure is to be defined solely by the claims that follow and the equivalents thereof. All changes coming within the meaning and equivalency of the claims are intended to be embraced therein.

Claims

1. A method for manufacturing an armature, the armature comprising an iron core and a coil, the iron core comprising slots, the coil being mounted in the slots, wherein: Each of the grooves includes a constant portion and an enlarged portion, wherein the constant portion has a constant circumferential width, and the enlarged portion is arranged radially outside the constant portion and is formed so that the width increases toward the radial outside. The method comprises: an arranging step of arranging conductors in a row in each of the slots across the constant portion and the expanded portion, the conductors being included in the coil and each having an outer surface covered by an insulating cover; and a first pressurizing step of pressurizing the conductors arranged in the slots in the arrangement step and causing the conductors to be plastically deformed using a first pressurizing jig, wherein the width of the first pressurizing jig is equal to the width of the constant portion; and In the first pressurizing step, the first pressurizing jig is moved within the range of the constant portion of the groove to plastically deform the conductors arranged in a row. The conductor disposed in the enlarged portion is in close contact with the inner peripheral surface of the enlarged portion in the circumferential direction. The configuration steps include: a first arranging step of arranging the conductors to be pressurized in the first pressurizing step in a row across the constant portion and the expanded portion of the slot; and a second arranging step of arranging a new conductor in the constant portion of the slot after performing the first pressurizing step; The method further includes a second pressurizing step of pressurizing the conductor arranged in the second arrangement step and plastically deforming the conductor using a second pressurizing jig, wherein the width of the second pressurizing jig is smaller than the width of the constant portion, and In the second pressurizing step, the second pressurizing jig is used to pressurize the radially innermost conductor in the constant portion of each slot in the radially outward direction, so that the conductor is plastically deformed to have a C-shaped cross section.

2. An armature comprising: an iron core having slots; and The coil is mounted in the slot, wherein Each of the grooves includes a constant portion and an enlarged portion, wherein the constant portion has a constant circumferential width, and the enlarged portion is arranged radially outside the constant portion and is formed so that the width increases toward the radial outside. The coil includes a configuration portion configured in the slot and a coil end configured outside the slot. Each of the arrangement portions is formed of a conductor included in the coil and each having an outer surface covered by an insulating cover, the conductors being arranged in a row across the constant portion and the expanded portion of a corresponding one of the slots. Adjacent conductors in the conductor arrangement portion each include a contact surface, the contact surfaces of the adjacent conductors are in contact with each other, and the widths of the contact surfaces in the circumferential direction are equal to each other, and The opposing surface of the conductor, which is opposed to the inner peripheral surface of the corresponding slot, is in close contact with the inner peripheral surface. The conductor disposed in the enlarged portion is in close contact with the inner peripheral surface of the enlarged portion in the circumferential direction. The number of the conductors arranged in a row across the constant portion and the expanded portion of the corresponding slot is three or more, A conductor located most radially inner than the conductors in the constant portion of each slot has a C-shaped cross section.

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