Armature, rotary electric machine, linear motor, and method for manufacturing armature

Abstract

Provided is an armature that has high insulation between adjacent coils in the same layer.　This armature is disposed so as to face a movable element via a gap. When a direction facing the movable element is defined as a first direction, a direction orthogonal to the first direction and in which the movable element moves relative to the armature is defined as a second direction, and a direction orthogonal to the first direction and the second direction is defined as a third direction, the armature comprises a coil the width of which varies along the third direction as viewed from the first direction. Coils (41, 42) are laminated in two or more layers via an insulator in the first direction, at least two or more coils (41, 43) are disposed in the second direction, and chamfered parts (40) are formed in the corner parts of the coils in a cross section in a direction orthogonal to the third direction.

Description

Armature, rotating electric machine, linear motor, and method of manufacturing the armature

[0001] The present disclosure relates to an armature, a rotating electric machine, a linear motor, and a method for manufacturing an armature.

[0002] A thin rotating electric machine is an axial gap type rotating electric machine in which a ring-shaped rotor and an armature are arranged facing each other. For example, an armature for an axial gap type rotating electric machine is disclosed in which a plurality of coils manufactured by punching copper plate are stacked with an insulating layer sandwiched therebetween (see, for example, Patent Document 1).

[0003] JP 2008-99429 A

[0004] In conventional armatures, multiple coils made by punching copper sheets are stacked with insulating layers in between, which poses the problem of poor insulation between adjacent coils on the same layer.

[0005] The present disclosure has been made to solve the above-mentioned problems, and has an object to provide an armature with high insulation between adjacent coils in the same layer.

[0006] The armature of the present disclosure is an armature arranged opposite the mover across a gap, and has a coil whose width changes from the first direction toward the third direction when viewed from the first direction, where the direction opposite the mover is defined as a first direction, the direction perpendicular to the first direction and in which the mover moves relative to the armature is defined as a second direction, and the direction perpendicular to the first and second directions is defined as a third direction, the coils are stacked in two or more layers in the first direction with an insulator interposed between them, at least two coils are arranged in the second direction, and chamfered portions are formed at the corners of the coils in a cross section perpendicular to the third direction.

[0007] In the armature of the present disclosure, chamfered portions are formed at the corners of the coils in a cross section perpendicular to the third direction, thereby improving the insulation between adjacent coils in the same layer.

[0008] 1 is a cross-sectional view of a rotating electric machine according to embodiment 1. FIG. 2 is a plan view of a rotor according to embodiment 1. FIG. 3 is a plan view of an armature according to embodiment 1. FIG. 4 is a side view of the armature according to embodiment 1. FIG. 5 is a plan view of the armature according to embodiment 1. FIG. 6 is a circuit diagram of the armature according to embodiment 1. FIG. 7 is a plan view of an armature of a reference example according to embodiment 1. FIG. 8 is an enlarged cross-sectional view of a coil of the armature according to embodiment 1. FIG. 9 is an enlarged cross-sectional view of a coil of an armature of a comparative example according to embodiment 1. FIG. 10 is an enlarged view of a coil of the armature according to embodiment 1. FIG. 11 is an enlarged view of a coil of the armature according to embodiment 1. FIG. 12 is a flowchart showing a manufacturing method of the armature according to embodiment 1. FIG. 13 is a view showing a coil in the middle of manufacturing according to embodiment 1. FIG. 14 is a view for explaining a manufacturing method of the armature according to embodiment 1. FIG. 15 is a view for explaining a manufacturing method of the armature according to embodiment 1. FIG. 16 is a view for explaining deformation of the coil in the armature according to embodiment 1 when pressed with a die. FIG. 17 is a view for explaining deformation of the coil in the armature according to embodiment 1 when pressed with a die. FIG. 18 is a view for explaining deformation of the coil in the armature according to embodiment 1 when pressed with a die. FIG. 19 is a plan view of an armature according to embodiment 1. 1 is an enlarged cross-sectional view of a coil of an armature according to embodiment 2. FIG. 2 is an enlarged view of a coil of an armature according to embodiment 2. FIG. 3 is an enlarged cross-sectional view of a coil of an armature according to embodiment 3. FIG. 4 is an enlarged cross-sectional view of a coil of an armature of a comparative example according to embodiment 3. FIG. 5 is an enlarged cross-sectional view of a coil of an armature according to embodiment 3. FIG. 6 is an enlarged cross-sectional view of a coil of an armature according to embodiment 3. FIG. 7 is an enlarged cross-sectional view of a coil of an armature according to embodiment 4. FIG. 8 is an enlarged cross-sectional view of a coil of an armature according to embodiment 4. FIG. 9 is an enlarged cross-sectional view of a coil of an armature according to embodiment 5. FIG. 10 is an enlarged view of a coil of an armature according to embodiment 5.

[0009] Armatures according to embodiments of the present disclosure will be described in detail below with reference to the drawings. Note that the same reference numerals in the various drawings indicate the same or corresponding parts.

[0010] Embodiment 1. Fig. 1 is a cross-sectional view of a rotating electric machine according to embodiment 1. Fig. 1 is a cross-sectional view showing the structure of the right half from the center of rotation, which will be described later, in order to explain the structure of the rotating electric machine according to this embodiment. The rotating electric machine 1 of this embodiment is an axial gap type rotating electric machine in which an annular rotor and an armature are arranged facing each other in the axial direction.

[0011] The rotating electric machine 1 of this embodiment is composed of a stator 2 and a rotor 3. The stator 2 has an annular armature 21, a housing 22 that holds the armature 21, a bearing 23, and a bracket 24. The rotor 3 has a rotating shaft 31 that is rotatably supported relative to the stator 2 via the bearing 23, an annular rotor core 32 that is fastened to the rotating shaft 31, and magnets 33 that are arranged in the circumferential direction of the rotor core 32.

[0012] The rotating shaft 31 rotates around the center of rotation C. Hereinafter, the direction parallel to the center of rotation C will be referred to as the axial direction, the direction perpendicular to the axial direction as the radial direction, and the circumferential direction of the annular armature 21 as the circumferential direction. Furthermore, the inner diameter side refers to the direction approaching the center of rotation C in the radial direction, and the outer diameter side refers to the direction moving away from the center of rotation C in the radial direction. The rotor core 32 is disposed on both sides of the armature 21 in the axial direction, and the magnets 33 are disposed facing the armature 21 across a gap in the axial direction. A coil is formed in the armature 21, and a current is applied to this coil from the power supply terminal 4. The armature 21 generates a rotating magnetic field due to the applied current. The rotor 3 rotates due to this rotating magnetic field. Therefore, the rotor 3 can also be described as a mover that is disposed coaxially with the armature 21 across a gap and moves relative to the armature 21.

[0013] Fig. 2 is a plan view of the rotor 3 of this embodiment, viewed from the armature 21 side. As shown in Fig. 2, in the rotor 3 of this embodiment, the magnets 33 are arranged in a line in the circumferential direction of the annular rotor core 32. The magnets 33 are magnetized in a direction perpendicular to the plane of the paper in Fig. 2, with south poles and north poles arranged alternately in the circumferential direction.

[0014] Fig. 3 is a plan view of the armature 21 of this embodiment, and Fig. 4 is a side view of the armature 21 of this embodiment. The armature 21 of this embodiment is composed of two layers of coils stacked in the axial direction. Therefore, Fig. 3 shows the coils of the first layer. Fig. 5 is a plan view of the coils of the second layer of the armature 21 of this embodiment. The coils of each layer are made of a conductive metal such as copper, and an insulating coating is formed on the surface.

[0015] As shown in FIGS. 3 and 5 , the armature 21 of this embodiment has 72 coils 26 divided circumferentially by slits 25. Each coil 26 includes a slot 26a in the radial center, an outer turn portion 26b located radially outward from the slot 26a, and an inner turn portion 26c located radially inward from the slot 26a. The first-layer coil 26 is joined to the second-layer coil 26 at an outer joint 27. The second-layer coil 26 joined at the outer joint 27 is joined to the first-layer coil 26 at an inner joint 28. The thus-joined coils 26 are joined to the coils 26 located six pitches apart circumferentially by a bus bar 29. The bus bar 29 may be used for purposes other than electrically connecting the coils in the stacking direction. For example, it may be used to connect the neutral point in a Y-connection. Furthermore, the bus bar 29 is not limited to joining coils spaced apart by six slot pitches, but may join coils spaced apart by five slot pitches or seven slot pitches.

[0016] The first and second layer coils, which are six pitches apart, are joined in sequence to form a wave-wound armature coil. The armature of this embodiment has a distributed winding with full pitch winding of 2 per pole per phase, and as shown in Figure 3, the coils U1, U2, W1, W2, V1, and V2 are arranged in this order. Also, as shown in Figure 4, power supply terminals 4 are connected to both ends of the coils U1, U2, W1, W2, V1, and V2.

[0017] 6 is a circuit diagram of an armature according to this embodiment. A U-phase coil, in which U1 and U2 coils are connected in series, a W-phase coil, in which W1 and W2 coils are connected in series, and a V-phase coil, in which V1 and V2 coils are connected in series, are connected in a Y-connection, and a three-phase AC power supply 30 such as an inverter is connected to the ends of the coils of each phase. A rotating magnetic field is generated in the armature by applying a three-phase AC current from the three-phase AC power supply 30 to the coils of each phase.

[0018] In this embodiment, the armature is of distributed winding with full pitch winding of two coils per pole per phase, but the armature may be of fractional pitch winding, distributed winding with one coil per pole per phase, salient pole concentrated winding, etc., as long as the winding method generates a rotating magnetic field and the coils set to different potentials are arranged adjacent to each other. Furthermore, the armature of this embodiment is not limited to three phases, and can also be applied to a dual three-phase structure or a structure that generates a rotating magnetic field with five-phase or seven-phase current.

[0019] Fig. 7 is a plan view of an armature wound with magnet wire of the same cross-sectional shape as a reference example. Note that bus bars and power supply terminals are omitted from Fig. 7. In this reference example, the width of the coil 26 must be determined by physical constraints such as space interference constraints on the inner diameter and ensuring insulation distance. In this case, the space other than the coil becomes large on the outer diameter side. As a result, it is not possible to increase the coil space factor, which leads to reduced efficiency and reduced output.

[0020] In contrast, in the armature of this embodiment, as shown in Figure 3, the coil width as viewed from the axial direction is varied, allowing the coils to be densely arranged even on the outer diameter side, resulting in higher efficiency and higher output. On the other hand, in order to obtain coil shapes with different cross-sectional areas, the coils must be formed by stamping, laser processing, etching, etc. For example, when the coils are formed by stamping, the corners of the coils will have a shape that is close to a right angle.

[0021] FIG. 8 is an enlarged cross-sectional view of a coil of an armature according to this embodiment. FIG. 8 is a cross-sectional view of the portion indicated by A-A in FIG. 3, i.e., a cross-sectional view perpendicular to the radial direction, with the vertical direction of the page being the axial direction and the horizontal direction being the circumferential direction. FIG. 8 shows an enlarged view of a slot portion in which coils of different phases are adjacent in the circumferential direction. In FIG. 8, for example, coils 41 and 42, which are stacked in two layers in the axial direction, are U-phase coils, and coils 43 and 44, which are stacked in two layers in the axial direction, are W-phase coils. These coils 41 to 44 are covered with an insulating coating 45. The potential difference between coils 41 and 43 of different phases is greater than the potential difference between coils 41 and 42 of the same phase.

[0022] As shown in FIG. 8 , in the armature of this embodiment, the corners of the coils are chamfered in a radial cross section. Here, chamfering refers to removing sharp corners after machining to form a flat, curved surface, or the like, and the chamfered shape refers to a shape that can reduce electric field concentration by removing sharp corners. Specifically, in the armature of this embodiment, the corners of the coils are rounded. Hereinafter, the chamfered shape will be referred to as chamfered portion 40. Note that, as long as the shape of the chamfered portion defined in this embodiment is achieved, it is not limited to a processing method that removes sharp corners after machining, but may also be a processing method that directly forms a chamfered portion using a near-net shape by a 3D printer, die casting, or the like.

[0023] FIG. 9 is an enlarged cross-sectional view of a coil of an armature of a comparative example according to the present embodiment. FIG. 9 is a cross-sectional view in a direction perpendicular to the radial direction, with the vertical direction of the page being the axial direction and the horizontal direction being the circumferential direction. FIG. 9 shows an enlarged view of a slot portion in which coils of different phases are adjacent in the circumferential direction. In FIG. 9, for example, coils 41 and 42 stacked in two layers in the axial direction are U-phase coils, and coils 43 and 44 stacked in two layers in the axial direction are W-phase coils. These coils 41 to 44 are covered with an insulating coating 45. The potential difference between coils 41 and 43 of different phases is larger than the potential difference between coils 41 and 42 of the same phase.

[0024] In the armature of the comparative example shown in Fig. 9, the corners of the coils are not chamfered, so the corners of the coils are nearly right-angled in the radial cross section. In this embodiment, if the corners of the coils are not chamfered in the radial cross section, the corners of the coils will be nearly right-angled.

[0025] FIG. 10 is an enlarged view of the portion indicated by the dashed circle in FIG. 8 , and FIG. 11 is an enlarged view of the portion indicated by the dashed circle in FIG. 9 . As shown in FIGS. 10 and 11 , three locations are assumed to be potential locations where short-circuiting with other coils occurs, based on coil 41: between the corner of coil 41 indicated by double-headed arrow a and the corner of coil 42; between the corner of coil 41 indicated by double-headed arrow b and the corner of coil 43; and between the corner of coil 41 indicated by double-headed arrow c and the corner of coil 44. The lengths of double-headed arrow a and double-headed arrow b are the same between the armature of this embodiment and the armature of the comparative example. However, in the armature of this embodiment shown in FIG. 10 , the corners are shaped like chamfered portions 40, so electric field concentration is alleviated compared to the armature of the comparative example shown in FIG. 11 .

[0026] The length of double-ended arrow c is longer in the armature of this embodiment shown in Fig. 10 than in the armature of the comparative example shown in Fig. 11. Therefore, the insulation between the corners of coil 41 and coil 44 is higher in the armature of this embodiment than in the armature of the comparative example. Furthermore, in the armature of this embodiment, the corners are chamfered, so electric field concentration is alleviated compared to the armature of the comparative example shown in Fig. 11.

[0027] As described above, in the armature of this embodiment, the corners of the coils in the radial cross section are chamfered portions 40, which improves the insulation between adjacent coils in the same layer. Furthermore, in the armature of this embodiment, the insulation between adjacent coils in the same layer is improved compared to the armature of the comparative example, so the thickness of the insulating coating 45 can be reduced. Reducing the thickness of the insulating coating 45 also improves the coil space factor. As a result, there are also effects of realizing a smaller armature, higher output, and higher efficiency.

[0028] In the armature of this embodiment, the chamfered portion has a rounded shape, but the chamfered portion may have a shape called C-chamfering, in which a sharp corner after machining is chamfered at a 45-degree angle, a shape called light chamfering, in which only the tip of a sharp corner is chamfered, or a shape in which a sharp corner is chamfered into a polygonal shape.

[0029] Next, a method for manufacturing the armature according to this embodiment will be described. Fig. 12 is a flowchart showing the method for manufacturing the armature according to this embodiment. The method for manufacturing the armature according to this embodiment comprises a coil forming step S1, a chamfered portion forming step S2, an insulating coating forming step S3, a coil joining step S4, and a coil cutting step S5.

[0030] First, in the coil formation process S1, a coil is formed by punching or laser processing a sheet-shaped metal plate such as copper to form a slit. Fig. 13 is a diagram showing the coil after the slit has been formed in the coil formation process S1. As shown in Fig. 13, in the coil formation process S1, the metal plate 34 is processed into a ring shape, and a slit 25 is formed through the metal plate 34. By forming the slit 25, a coil 26 is formed in the metal plate 34, which is composed of a slot portion 26a, an outer diameter turn portion 26b, and an inner diameter turn portion 26c.

[0031] In the coil forming step S1, the outer diameter joint portion 27 and the inner diameter joint portion 28 are formed at the same time as the coil 26 is formed. At this time, the outer diameter joint portion 27 is connected to the outer diameter connecting portion 36 via the outer diameter cutting portion 35. Furthermore, the inner diameter joint portion 28 is connected to the inner diameter connecting portion 38 via the inner diameter cutting portion 37. Furthermore, in the coil forming step S1, a positioning hole 39 is formed in the outer diameter connecting portion 36.

[0032] By connecting the coil 26 to the outer diameter connecting portion 36 and the inner diameter connecting portion 38 in this manner, the coil can be easily transported, and by forming the positioning holes 39, positioning in subsequent processes can be easily performed.

[0033] Next, in the chamfer forming step S2, chamfers are formed at the corners of the coil in a radial cross section. FIG. 14 is a diagram for explaining the chamfer forming step S2. The coil 26 formed in the coil forming step S1 has corners that are approximately right angles. As shown in FIG. 14, the coil 26 is placed on a lower mold 51. An upper mold 52 is pressed from above onto the coil 26 placed on the lower mold 51. Through this process, chamfers 40 are formed at the corners of the coil 26. Note that, as shown in FIG. 15, multiple coils 26 arranged in the circumferential direction may be pressed simultaneously using the lower mold 51 and the upper mold 52. Alternatively, the entire coil 26 may be pressed simultaneously.

[0034] FIG. 16 is a diagram illustrating the deformation of a coil when a limited number of coils are pressed with a die. In FIG. 16, the arrows indicate the force applied from the coil 26 to the upper die 52. Note that a similar force is also applied to the lower die 51, but this is not shown. As shown in FIG. 16, a force is applied perpendicular to the coil at the end of the upper die 52, which may cause deformation of the die. In an actual coil, a small circumferential gap is desirable to improve the coil space factor, so the thickness of the die at the circumferential end is small. If the circumferential gap of the coil is increased to suppress die deformation, the output of the rotating electric machine will decrease.

[0035] Figure 17 is a diagram illustrating the deformation of coils when a limited number of coils are pressed with a die. As shown in Figure 17, a method of forming a chamfer on only one side of the coil adjacent to the die edge is also possible. In this case, the imbalance of force on the die is smaller than in the method shown in Figure 16, but the coil adjacent to the die edge will move. If the coil shifts circumferentially, in the worst case scenario, a short circuit will occur with the adjacent coil. Even if a short circuit does not occur, the required insulation distance cannot be secured, and insulation reliability cannot be ensured.

[0036] FIG. 18 is a diagram illustrating the deformation of the coil when the entire coil is pressed simultaneously with a mold. As shown in FIG. 18, when the entire coil is pressed simultaneously with a mold, the circumferential ends of the mold are eliminated, which has the effect of suppressing deformation of the coil 26. Suppressing deformation of the coil 26 and reducing variations in the circumferential gap of the coil has the effect of improving insulation reliability. Furthermore, when the entire coil 26 is pressed simultaneously, the force acting on the mold is reduced because the ends are eliminated, which has the effect of extending the life of the mold. Furthermore, pressing the entire coil 26 simultaneously can also prevent warping of the coil.

[0037] Next, in the insulating coating forming step S3, an insulating coating is formed on the surface of the coil. The insulating coating can be formed by electro-deposition coating, powder coating, or the like.

[0038] The first and second layer coils are manufactured by carrying out the coil forming step S1, the chamfered portion forming step S2, and the insulating coating forming step S3 on two metal plates, respectively.

[0039] Next, in the coil joining step S4, first, the insulating coating formed on the surfaces of the outer diameter joining portion 27 and the inner diameter joining portion 28 is peeled off. After that, the first layer coil and the second layer coil are overlapped and joined at the outer diameter joining portion 27 and the inner diameter joining portion 28. The coils can be joined by methods such as welding, crimping, and soldering. Furthermore, in the coil joining step S4, the power supply terminal 4 and the bus bar 29 are joined to the coil 26, respectively.

[0040] Finally, in the coil cutting step S5, the outer diameter cutting portion 35 and the inner diameter cutting portion 37 are cut to separate the outer diameter connecting portion 36 and the inner diameter connecting portion 38 from the coil 26. Through these steps, the armature of this embodiment is manufactured.

[0041] In the chamfer forming step S2 of this embodiment, a method of forming the chamfer by pressing the corners of the coil using a mold has been described. However, the chamfer may also be formed by cutting the corners of the coil using an abrasive. Methods using an abrasive, such as sandblasting, shot blasting, and barrel polishing, may also be used. The method using an abrasive can form the chamfer without using a mold, which has the effect of reducing costs. Furthermore, the abrasive increases the surface roughness of the coil, improving adhesion between the coil and the insulating coating and suppressing pinholes and peeling in the insulating coating. As a result, the reliability of the coil's insulation is improved.

[0042] Furthermore, in the armature manufacturing method of this embodiment, the insulating coating is formed after chamfering the coil corners, which allows for a more uniform thickness of the insulating coating at the coil corners compared to coils without chamfering. If the insulating coating were formed without chamfering, the thickness of the insulating coating would be uneven due to electric field concentration at the corners. Therefore, to ensure the insulating properties of the insulating coating, it is necessary to increase the average thickness of the entire insulating coating. As a result, armatures without chamfering have a lower coil space factor. In the armature manufacturing method of this embodiment, the insulating coating is formed after chamfering the coil corners, which eliminates the need to increase the average thickness of the insulating coating more than necessary, thereby also improving the coil space factor.

[0043] In the method for manufacturing the armature of this embodiment, an example has been shown in which the coil 26 is processed while connected to the outer diameter connecting portion 36 and the inner diameter connecting portion 38, but the coil 26 may also be processed while separated. Even in this case, by providing the chamfered portion forming step S2 before the insulating coating forming step S3, the thickness of the insulating coating at the corners of the coil can be made uniform.

[0044] Although the present embodiment has been described as an armature for an axial gap type rotating electric machine, the same effect as this embodiment can be obtained by forming chamfered portions at the corners of the coils in an armature for a linear motor in which disk-shaped coils 26 are linearly arranged as shown in Fig. 19. Also, in a radial gap type rotating electric machine in which an armature is constructed by processing linearly arranged coils into a cylindrical shape, the same effect as this embodiment can be obtained by forming chamfered portions at the corners of the coils.

[0045] Furthermore, although the present embodiment has been described as an example of an armature configured with two layers of coils, the same effect as this embodiment can be obtained in an armature configured with three or more layers of coils by forming chamfered portions at the corners of the coils. By multi-layering the coils, the axial thickness of the coils can be reduced, thereby reducing the skin effect, eddy current loss, and the like. Furthermore, although the armature of this embodiment has been described as an example of Y-connected coils, it may also be a coil with parallel connection, delta connection, or the like.

[0046] Embodiment 2. In an armature according to embodiment 2, two layers of coils are arranged circumferentially offset from each other in the armature of embodiment 1. Note that a rotating electric machine having an armature according to this embodiment is similar to the rotating electric machine shown in FIG. 1 according to embodiment 1.

[0047] FIG. 20 is an enlarged cross-sectional view of a coil of an armature according to this embodiment. FIG. 20 is a cross-sectional view in a direction perpendicular to the radial direction, with the vertical direction of the page being the axial direction and the horizontal direction being the circumferential direction. FIG. 20 shows an enlarged view of a slot portion in which coils of different phases are adjacent in the circumferential direction. In FIG. 20, for example, coils 41 and 42, which are stacked in two layers in the axial direction, are U-phase coils, and coils 43 and 44, which are stacked in two layers in the axial direction, are W-phase coils. These coils 41 to 44 are covered with an insulating coating 45.

[0048] As shown in Fig. 20 , in the armature of this embodiment, chamfered portions 40 are formed at the corners of the coils in a radial cross section. Furthermore, in the armature of this embodiment, the coils in the second layer are arranged circumferentially shifted relative to the coils in the first layer. Fig. 21 is an enlarged view of the portion indicated by the dashed circle in Fig. 20 . As shown in Fig. 21 , in the armature of this embodiment, the corners of axially adjacent coils do not face each other, but the corner of one coil faces the flat portion of the axially adjacent coil. Therefore, in the armature of this embodiment, the insulation is improved compared to the armature of embodiment 1, in which the corners of axially adjacent coils face each other.

[0049] 21 , the amount of circumferential deviation between axially adjacent coils is X, the distance between circumferentially adjacent coils is Y, and the distance from the circumferential end of a coil to the start position of chamfered portion 40 is R. In the armature of this embodiment, it is preferable that X>R. By satisfying this condition, corners of axially adjacent coils do not face each other, and a corner of one coil always faces a flat portion of an axially adjacent coil.

[0050] Furthermore, in the armature of this embodiment, it is preferable that X<Y+2R. If X≧Y+2R, the distance between coils 42 and 43 of different phases becomes small, which may result in a decrease in insulation. By satisfying X<Y+2R, the distance between coils of different phases can be increased, thereby preventing a decrease in insulation.

[0051] Embodiment 3 In the armature of embodiment 1, the two layers of coils stacked in the axial direction ensure insulation between the coils by an insulating coating formed on the surface of the coils. In the armature according to embodiment 3, an insulating sheet is placed between the two layers of coils stacked in the axial direction to ensure insulation between the coils. Note that a rotating electric machine having an armature of this embodiment is similar to the rotating electric machine shown in FIG. 1 of embodiment 1.

[0052] FIG. 22 is an enlarged cross-sectional view of a coil of an armature according to this embodiment. FIG. 22 is a cross-sectional view in a direction perpendicular to the radial direction, with the vertical direction of the page being the axial direction and the horizontal direction being the circumferential direction. FIG. 22 shows an enlarged view of a slot in which coils of different phases are adjacent in the circumferential direction. In FIG. 22, for example, coils 41 and 42, which are stacked in two layers in the axial direction, are U-phase coils, and coils 43 and 44, which are stacked in two layers in the axial direction, are W-phase coils. Chamfered portions 40 are formed at the corners of these coils 41 to 44. Furthermore, no insulating coating is formed on the surfaces of these coils 41 to 44, and insulating sheets 46 are disposed between axially adjacent coils.

[0053] The armature of this embodiment is manufactured by excluding the insulating coating forming step S3 from the armature manufacturing method shown in FIG. 12 of the first embodiment, and by arranging an insulating sheet in areas other than the outer diameter joint portion and the inner diameter joint portion when overlapping the first layer coil and the second layer coil in the coil joining step S4.

[0054] FIG. 23 is an enlarged cross-sectional view of a coil of an armature of a comparative example according to the present embodiment. FIG. 23 is a cross-sectional view in a direction perpendicular to the radial direction, with the vertical direction of the page being the axial direction and the horizontal direction being the circumferential direction. FIG. 23 shows an enlarged view of a slot in which coils of different phases are adjacent in the circumferential direction. In FIG. 23, for example, coils 41 and 42, which are stacked in two layers in the axial direction, are U-phase coils, and coils 43 and 44, which are stacked in two layers in the axial direction, are W-phase coils. No chamfers are formed at the corners of these coils 41 to 44. Furthermore, no insulating coating is formed on the surfaces of these coils 41 to 44, and an insulating sheet 46 is disposed between axially adjacent coils.

[0055] Fig. 24 is an enlarged view of the portion indicated by the dashed circle in Fig. 22, and Fig. 25 is an enlarged view of the portion indicated by the dashed circle in Fig. 23. In Figs. 24 and 25, the creepage distance between circumferentially adjacent coils is indicated by a double-headed arrow d. The length of the double-headed arrow d is longer in the armature of the present embodiment shown in Fig. 24 than in the armature of the comparative example shown in Fig. 25. Therefore, the insulation between circumferentially adjacent coils is higher in the armature of the present embodiment in which chamfered portion 40 is formed than in the armature of the comparative example.

[0056] Fig. 26 is an enlarged cross-sectional view of a coil of an armature of another comparative example according to the present embodiment. The armature of the comparative example shown in Fig. 26 employs a punching process in the coil forming process, and does not have a chamfered portion.

[0057] As shown in Figure 26, when punching is used in the coil formation process, protrusions 47 called burrs are generated at the corners of the coil. In the armature of this comparative example, which does not have chamfered portions, these protrusions 47 can damage the insulating sheet 46, potentially reducing the insulating properties of the insulating sheet 46. Even if the protrusions 47 do not damage the insulating sheet 46, gaps 48 can still form between the insulating sheet 46 and the protrusions 47. These gaps 48 reduce the coil space factor and increase the thermal resistance from the coil to the insulating sheet. As a result, a rotating electric machine equipped with the armature of this comparative example experiences a decrease in output.

[0058] In contrast, in the armature of this embodiment, the coil and the insulating sheet are in close contact with each other as shown in Fig. 24, so the space factor of the coil can be improved and the thermal resistance from the coil to the insulating sheet can be reduced. As a result, a rotating electric machine equipped with the armature of this embodiment can achieve high output.

[0059] Embodiment 4 In the armature of embodiment 3, an insulating sheet is disposed between two layers of coils stacked in the axial direction. The armature of embodiment 4 is the armature of embodiment 3, in which adjacent coils in the circumferential direction are fixed with fixing members. Note that a rotating electric machine having an armature of this embodiment is similar to the rotating electric machine of embodiment 1 shown in FIG. 1.

[0060] FIG. 27 is an enlarged cross-sectional view of a coil of an armature according to this embodiment. FIG. 27 is a cross-sectional view perpendicular to the radial direction, with the vertical direction of the page representing the axial direction and the horizontal direction representing the circumferential direction. FIG. 27 shows an enlarged view of a slot in which coils of different phases are adjacent in the circumferential direction. In FIG. 27, for example, coils 41 and 42, which are stacked in two layers in the axial direction, are U-phase coils, and coils 43 and 44, which are stacked in two layers in the axial direction, are W-phase coils. Chamfered portions 40 are formed at the corners of these coils 41 to 44. Furthermore, no insulating coating is formed on the surfaces of these coils 41 to 44, and an insulating sheet 46 is disposed between adjacent coils in the axial direction. Furthermore, fixing members 49 are disposed between adjacent coils 41 and 43 in the circumferential direction and between adjacent coils 42 and 44 in the circumferential direction. The fixing members 49 secure adjacent coils in the circumferential direction. Examples of fixing members 49 include thermosetting resins and room-temperature curing adhesives.

[0061] An armature configured in this manner has improved rigidity, which has the effect of suppressing vibration and noise. Fig. 28 is an enlarged cross-sectional view of a coil of another armature according to this embodiment. Fig. 28 is a cross-sectional view in a direction perpendicular to the radial direction, with the vertical direction on the page being the axial direction and the horizontal direction being the circumferential direction. As shown in Fig. 28, in the armature of this embodiment, it is preferable that the surface of the fixing member 49 is curved.

[0062] Fig. 29 is an enlarged view of the portion indicated by the dashed circle in Fig. 27, and Fig. 30 is an enlarged view of the portion indicated by the dashed circle in Fig. 28. In Figs. 29 and 30, the creepage distance between circumferentially adjacent coils is indicated by a double-headed arrow d. The length of the double-headed arrow d is longer in the armature shown in Fig. 30 than in the armature shown in Fig. 29. Therefore, the insulation between circumferentially adjacent coils is higher in the armature shown in Fig. 30 than in the armature shown in Fig. 29. For these reasons, in the armature of this embodiment, it is preferable that the surface of the fixing member 49 is curved.

[0063] Embodiment 5 The armature of embodiment 5 is the armature of embodiment 1, in which a magnetic member is disposed between circumferentially adjacent coils. Note that a rotating electric machine having an armature of this embodiment is similar to the rotating electric machine of embodiment 1 shown in FIG. 1.

[0064] FIG. 31 is an enlarged cross-sectional view of a coil of the armature according to this embodiment. FIG. 31 is a cross-sectional view perpendicular to the radial direction, with the vertical direction of the page representing the axial direction and the horizontal direction representing the circumferential direction. FIG. 31 also shows an enlarged view of a slot in which coils of different phases are adjacent in the circumferential direction. In FIG. 31 , for example, coils 41 and 42, which are stacked in two layers in the axial direction, are U-phase coils, and coils 43 and 44, which are stacked in two layers in the axial direction, are W-phase coils. Chamfered portions 40 are formed at the corners of these coils 41 to 44. These coils 41 to 44 are also coated with an insulating coating 45. Furthermore, in the armature according to this embodiment, a magnetic member 50 is inserted between the circumferentially adjacent coils. FIG. 32 is an enlarged view of the portion indicated by the dashed circle in FIG. 31. The magnetic member 50 can be, for example, a material obtained by solidifying magnetic metal particles, such as iron-based or iron-silicon-based particles, with a resin.

[0065] The magnetic member 50 may be inserted into at least a portion of the circumferentially adjacent coils. For example, the magnetic member may be inserted only between the slots 26a of the coil 26 in FIG. 5 of the first embodiment. Because magnetic members are usually conductive, it is necessary to ensure insulation between the coil and the magnetic member. Even in this case, however, providing the coil with a chamfered portion has the effect of improving insulation. Furthermore, in the portions where no magnetic material is inserted, the coils are adjacent to each other in the circumferential direction without any magnetic material in between, so the same effect as in the first embodiment can be expected.

[0066] In an armature configured in this manner, the magnetic resistance of the armature as a magnetic circuit is reduced, so that a large torque can be obtained with the same current value. As a result, a rotating electric machine equipped with the armature of this embodiment can achieve high output.

[0067] Various aspects of the present disclosure are described below as appendices. (Appendix 1) An armature disposed opposite a mover across a gap, the armature having a coil whose width changes from the first direction toward the third direction when viewed from the first direction, where a direction facing the mover is defined as a first direction, a direction perpendicular to the first direction and in which the mover moves relative to the armature is defined as a second direction, and a direction perpendicular to the first and second directions is defined as a third direction, the coils are stacked in two or more layers in the first direction with an insulator interposed therebetween, at least two of the coils are arranged in the second direction, and chamfered portions are formed at corners of the coils in a cross section perpendicular to the third direction. (Appendix 2) The armature according to Appendix 1, wherein the coils adjacent to each other in the stacking direction are shifted from each other in a direction perpendicular to the stacking direction. (Appendix 3) The armature according to Appendix 2, wherein X is an amount of shift between the coils adjacent to each other in the stacking direction in a direction perpendicular to the stacking direction, and R is the distance between the end of the coil and the start position of the chamfered portion, and X>R. (Appendix 4) The armature according to Appendices 3, characterized in that X<Y+2R, where Y is the distance between the coils adjacent in a direction perpendicular to the lamination direction. (Appendix 5) The armature according to any one of Appendices 1 to 4, characterized in that an insulating coating is formed on the surface of the coil. (Appendix 6) The armature according to any one of Appendices 1 to 4, characterized in that an insulating sheet is disposed between the coils adjacent to each other in the lamination direction. (Appendix 7) The armature according to Appendices 6, characterized in that a fixing member for fixing the coils to each other is disposed between the coils adjacent in the direction perpendicular to the lamination direction. (Appendix 8) The armature according to any one of Appendices 1 to 4, characterized in that a magnetic member is disposed between the coils adjacent in the direction perpendicular to the lamination direction. (Appendix 9) A rotating electric machine comprising the armature according to any one of Appendices 1 to 8, and a mover disposed coaxially opposite the armature with a gap interposed therebetween. (Supplementary Note 10) A linear motor comprising: the armature according to any one of Supplementary Notes 1 to 8; and a mover arranged linearly opposite the armature with a gap interposed therebetween.(Appendix 11) A method for manufacturing an armature, comprising: a coil forming step of forming two or more coils by drilling slits in a metal plate; a chamfering portion forming step of forming chamfered portions at corners of the two or more coils formed in the coil forming step; an insulating coating forming step of forming an insulating coating on the surfaces of the two or more coils on which the chamfered portions have been formed in the chamfering portion forming step; and a coil joining step of overlapping and joining the two or more coils on which the insulating coatings have been formed in the insulating coating forming step. (Appendix 12) A method for manufacturing an armature according to Appendix 11, characterized in that the chamfering portion forming step involves pressing the corners of the coils using a mold to form the chamfered portions. (Appendix 13) A method for manufacturing an armature according to Appendix 11, characterized in that the chamfering portion forming step involves cutting the corners of the coils using an abrasive to form the chamfered portions.

[0068] Although various exemplary embodiments and examples are described in this disclosure, the various features, aspects, and functions described in one or more embodiments are not limited to the application of a particular embodiment, but may be applied to the embodiments alone or in various combinations. Therefore, countless variations not illustrated are contemplated within the scope of the technology disclosed in this specification. For example, this includes cases where at least one component is modified, added, or omitted, or where at least one component is extracted and combined with components of another embodiment.

[0069] REFERENCE SIGNS LIST 1 Rotating electric machine, 2 Stator, 3 Rotor, 4 Power supply terminal, 21 Armature, 22 Housing, 23 Bearing, 24 Bracket, 25 Slit, 26 Coil, 26a Slot portion, 26b Outer diameter turn portion, 26c Inner diameter turn portion, 27 Outer diameter joint portion, 28 Inner diameter joint portion, 29 Bus bar, 30 Three-phase AC power supply, 31 Rotating shaft, 32 Rotor core, 33 Magnet, 34 Metal plate, 35 Outer diameter cut portion, 36 Outer diameter connecting portion, 37 Inner diameter cut portion, 38 Inner diameter connecting portion, 39 Positioning hole, 40 Chamfered portion, 41, 42, 43, 44 Coil, 45 Insulating coating, 46 Insulating sheet, 47 Protrusion, 48 Gap, 49 Fixing member, 50 Magnetic member, 51 Lower mold, 52 Upper mold.

Claims

1. An armature disposed opposite a mover across a gap, wherein the direction opposite the mover is defined as a first direction, the direction perpendicular to the first direction in which the mover moves relative to the armature is defined as a second direction, and the direction perpendicular to the first and second directions is defined as a third direction, the armature has a coil whose width changes from the first direction toward the third direction, the coils are stacked in two or more layers in the first direction with an insulator interposed between them, at least two or more of the coils are arranged in the second direction, and chamfered portions are formed at the corners of the coils in a cross section perpendicular to the third direction.

2. The armature according to claim 1, wherein the coils adjacent to each other in the stacking direction are arranged offset from each other in a direction perpendicular to the stacking direction.

3. The armature according to claim 2, characterized in that X is the amount of misalignment between adjacent coils in the stacking direction in a direction perpendicular to the stacking direction, and R is the distance between the end of the coil and the starting position of the chamfered portion, such that X>R.

4. The armature according to claim 3, wherein, when the distance between adjacent coils in a direction perpendicular to the lamination direction is Y, X<Y+2R.

5. An armature according to any one of claims 1 to 4, characterized in that an insulating coating is formed on the surface of the coil.

6. An armature according to any one of claims 1 to 4, characterized in that an insulating sheet is disposed between the coils adjacent to each other in the lamination direction.

7. The armature according to claim 6, wherein a fixing member for fixing the coils to each other is disposed between the coils adjacent in the direction perpendicular to the lamination direction.

8. An armature according to any one of claims 1 to 4, characterized in that a magnetic member is disposed between the coils adjacent in a direction perpendicular to the lamination direction.

9. A rotating electric machine comprising the armature according to any one of claims 1 to 8 and a mover arranged coaxially opposite the armature with a gap therebetween.

10. A linear motor comprising the armature according to any one of claims 1 to 8 and a mover arranged linearly opposite the armature with a gap between them.

11. A method for manufacturing an armature, comprising: a coil forming step of forming two or more coils by drilling slits in a metal plate; a chamfer forming step of forming chamfered portions at the corners of the two or more coils formed in the coil forming step; an insulating coating forming step of forming an insulating coating on the surfaces of the two or more coils on which the chamfered portions have been formed in the chamfer forming step; and a coil joining step of overlapping and joining the two or more coils on which the insulating coating has been formed in the insulating coating forming step.

12. The method for manufacturing an armature according to claim 11, wherein the chamfered portion forming step uses a die to press the corners of the coil to form the chamfered portions.

13. The method for manufacturing an armature according to claim 11, wherein the chamfered portion forming step involves cutting the corners of the coil using an abrasive to form the chamfered portions.

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