Method and device for manufacturing stator

Abstract

Provided is a method for manufacturing a stator with which it is possible to easily form a power line by bending of protrusions. In the method for manufacturing a stator by which protrusions 9 of a segment coil 7 held by a stator core 3 are bent, the tips 10a of the protrusions 9 are displaced to the radially outer side of the stator core 3, the protrusions 9 are bent so as to be positioned at first positions, the tips 10a of the bent protrusions 9 are displaced to the radially innter side thereof, and the bent portions 12a and 12b of the protrusions 9 are bent back so as to be positioned at second positions further to the radially outer side than the initial positions before the bending.

Description

Stator manufacturing method and device

[0001] The present invention relates to a method and apparatus for manufacturing a stator that bends protruding portions of segment coils held in a stator core.

[0002] Conventional methods and apparatus for manufacturing a stator include, for example, those described in Patent Document 1, which use an interlayer spreading member.

[0003] In this manufacturing method and device, the interlayer spreading member is radially engaged with the tips of the protrusions of the segment coils arranged in layers radially relative to the stator core, and in this state, the interlayer spreading member is moved radially outward from the stator core, bending the protrusions radially outward.

[0004] However, in this manufacturing method and device, when the tip of the protrusion disengages from the interlayer spreading member, it is displaced radially inward due to springback. Since the amount of springback is not constant, there is a problem that the position of the tip of the protrusion is likely to vary.

[0005] International Publication No. 2019 / 093515

[0006] The problem to be solved is that the positions of the tips of the protruding parts of the segment coils relative to the stator core tend to vary.

[0007] The present invention provides a method for manufacturing a stator, comprising: bending a tip of a protruding portion of a segment coil held by a stator core so that the tip is displaced radially outward or inward relative to the stator core to a first position; and then displacing the tip of the bent protruding portion to the other radial position so that the bent portion of the protruding portion is bent back to a second position that is one of the radially outward and inward positions relative to the initial position before bending.

[0008] The present invention also provides a stator manufacturing device that bends a protruding portion of a segment coil held by the stator core relative to the stator core. The manufacturing device includes: teeth arranged on at least one radial side of the stator core relative to a tip of the protruding portion; and a drive unit that moves the teeth in the radial direction to displace the tip of the protruding portion in the radial direction. The manufacturing device then bends the tip of the protruding portion of the stator core toward one of the radially outer and inner sides to a first position. The manufacturing device then displaces the tip of the bent protruding portion toward the other radially outer or inner side to unbend the bent portion of the protruding portion to a second position that is closer to the radially outer or inner side than its initial position before bending.

[0009] The present invention can stabilize the position of the tip of the protruding portion of the segment coil relative to the stator core.

[0010] FIG. 1 is a schematic perspective view showing a stator according to a first embodiment of the present invention. FIG. 2 is an enlarged cross-sectional view partially illustrating the stator of FIG. 1. FIG. 3 is an enlarged view showing a protruding portion of the stator of FIG. 1. FIG. 4 is a side view showing a manufacturing apparatus for the stator according to the first embodiment. FIG. 5 is an enlarged side view showing a state at the start of bending the protruding portion, according to the manufacturing method of the stator of the first embodiment. FIG. 6 is an enlarged side view showing a state during insertion of teeth of a bending jig into the protruding portion, according to the manufacturing method of the stator of the first embodiment. FIG. 7 is an enlarged side view showing a state in which teeth of a bending jig are inserted into the protruding portion, according to the manufacturing method of the stator of the first embodiment. FIGS. 8A and 8B are enlarged side views showing bending of the protruding portion, according to the manufacturing method of the stator of the first embodiment. FIG. 9 is an enlarged side view showing additional bending of the protruding portion, according to the manufacturing method of the stator of the first embodiment. FIG. 10 is an enlarged side view showing unbending of the protruding portion, according to the manufacturing method of the stator of the first embodiment. Fig. 11 is an enlarged side view showing the bending back of the protrusion in the method for manufacturing a stator according to Example 2 of the present invention. Fig. 12 is an enlarged side view showing the bending back of the protrusion in the method for manufacturing a stator according to Example 3 of the present invention. Fig. 13 is an enlarged side view showing additional bending of the protrusion after bending back in the method for manufacturing a stator according to Example 3.

[0011] The purpose of stabilizing the position of the tip of the protrusion relative to the stator core of the segment coil is achieved by bending the protrusion and then bending it back.

[0012] The method for manufacturing the stator involves bending the protrusions 9 so that the tip ends 10a of the protrusions 9 of the segment coils 7 held by the stator core 3 are displaced toward one of the radially outer and inner sides of the stator core 3 and positioned at a first position. Thereafter, the tip ends 10a of the bent protrusions 9 are displaced toward the other radially outer and inner side, and the bent portions of the protrusions 9 are bent back so that they are positioned at a second position that is radially outer or inner than the initial position before bending.

[0013] The bending and unbending may be performed in a state where the base end 10 b of the protrusion 9 is aligned with the axial direction of the stator core 3 .

[0014] Moreover, the bending and unbending may be performed with the tip 10a of the protrusion 9 aligned in the axial direction.

[0015] Alternatively, the bending and unbending may be performed with the tip portion 10a aligned with the intermediate portion 10c. In this case, after unbending, the tip portion 10a may be additionally bent with respect to the intermediate portion 10c so that it is aligned with the axial direction.

[0016] Alternatively, the bending may be performed with the tip portion 10a aligned with the intermediate portion 10c, and after bending, the tip portion 10a may be additionally bent with respect to the intermediate portion 10c so that it is aligned with the axial direction. In this case, the bending back may be performed with the tip portion 10a aligned with the axial direction.

[0017] The stator manufacturing device 15 bends the protruding portion 9 of the segment coil 7 and includes teeth 25a, 25b, and 25c and a drive unit 17. The teeth 25a, 25b, and 25c are arranged on at least one radial side of the stator core 3 with respect to the tip end 10a of the protruding portion 9. The drive unit 17 moves the teeth 25a, 25b, and 25c in the radial direction to displace the tip end 10a of the protruding portion 9 in the radial direction.

[0018] This manufacturing device 15 bends the protrusion 9 so that the tip 10a of the protrusion 9 is displaced toward one of the outer and inner sides in the radial direction and positioned at a first position, and then displaces the bent tip 10a of the protrusion 9 toward the other of the outer and inner sides in the radial direction, and bends back the bent portions 12a and 12b of the protrusion 9 so that the tip 10a is positioned at a second position that is either outer or inner in the radial direction than the initial position before bending.

[0019] The manufacturing apparatus 15 may include a restraining body 20. The restraining body 20 restrains the base end 10b of the protrusion 9 from the radial direction, and holds the base end 10b of the protrusion 9 in a state aligned with the axial direction of the stator core 3 when bending and unbending.

[0020] The teeth 25a, 25b, and 25c may be arranged on both radial sides of the protrusion 9. In this case, the teeth 25a, 25b, and 25c on both radial sides hold the tip 10a of the protrusion 9 in a state aligned with the axial direction when bending and unbending.

[0021] The manufacturing apparatus 15 may also include a pusher 21 that is movable in the radial direction relative to the teeth 25. In this case, bending and unbending are performed by moving the teeth 25a in the radial direction, with the tip portion 10a aligned with the intermediate portion 10c. After unbending, the pusher 21 presses the tip portion 10a against the teeth 25a, and the tip portion 10a is additionally bent relative to the intermediate portion 10c so that it is aligned with the axial direction.

[0022] Alternatively, if the manufacturing apparatus 15 includes a pusher 21, the pusher 21 may be used to press the tip portion 10a against the teeth 25a after bending, and the tip portion 10a may be additionally bent relative to the intermediate portion 10c so that it is aligned in the axial direction. In this case, the tooth 25a is moved to the other of the outer and inner radial directions, and the tip portion 10a is aligned in the axial direction.

[0023] In this case, the bending back may be performed in a state where the pusher 21 is moved together with the teeth 25a and pressed against the teeth 25a of the tip end portion 10a.

[0024] [Stator] Fig. 1 is a schematic perspective view showing a stator according to Example 1 of the present invention. Fig. 2 is an enlarged cross-sectional view showing a part of the stator in Fig. 1. Fig. 3 is an enlarged view showing a protruding portion of the stator in Fig. 1.

[0025] 1 and 2 constitute a rotating electric machine together with a rotor (not shown). The rotating electric machine is constituted, for example, as a three-phase (U-phase, V-phase, W-phase) eight-pole AC permanent magnet synchronous motor.

[0026] 1 and 2 show the state in which the stator coil 5 is assembled into the stator core 3. In the state shown in FIG. 1, the tip end 10a of the protrusion 9 of each segment coil 7 constituting the stator coil 5 is aligned along the axial direction (not bent in the circumferential direction). The axial direction refers to the direction along the axis of the stator core 3. The circumferential direction refers to the direction along the outer periphery of the stator core 3.

[0027] 1, the protruding portion 9 is bent in the circumferential direction and then joined by welding to form the stator coil 5. Thereafter, the coil end 10aa of the protruding portion 9 is coated with an insulating paint, and the stator coil 5 portion is sealed with resin, etc., to form the stator 1 for the rotating electric machine. In the following explanation, for convenience, the one shown in FIG. 1 will be described as the stator 1.

[0028] As described above, the stator 1 includes the stator core 3 and the stator coil 5. The stator core 3 is formed by laminating, for example, a plurality of annular electromagnetic steel plates or silicon steel plates. The stator core 3 includes a plurality of slots 3a spaced equally apart in the circumferential direction.

[0029] The stator coil 5 is provided on the stator core 3 for three phases and configured to have a wave-wound shape. The stator coil 5 is configured with a plurality of segment coils 7.

[0030] 1 to 3, each segment coil 7 is formed, for example, from a rectangular wire having a rectangular cross section into a U-shape, such as a hairpin shape. Note that the cross-sectional shape of the segment coil 7 is not particularly limited. Multiple segment coils 7 are combined around the stator core 3 in the circumferential direction.

[0031] Each segment coil 7 has its legs 8, including the coil ends 10aa without an insulating layer, inserted into the slots 3a of the stator core 3. This holds the segment coil 7 in place in the stator core 3. Note that an insulating layer is formed on the entire portion of the segment coil 7 except for the coil ends 10aa.

[0032] The leg portions 8 of the segment coil 7 penetrate the stator core 3. As a result, a portion of the leg portion 8, including the coil end 10aa, protrudes axially from the stator core 3 to form a protrusion 9. Note that Figures 1 and 2 show a state in which the leg portions 8 of the segment coil 7 are assembled to the stator core 3 from below and protrude upward.

[0033] The protrusions 9 are arranged in a row in the radial direction within each slot 3 a. In this embodiment, the first protrusion 9 a at the outermost periphery to the sixth protrusion 9 f at the innermost periphery are positioned within the slot 3 a according to the layer of the stator coil 5.

[0034] The first protrusion 9a (and the first protrusion 9Aa described later) to the innermost sixth protrusion 9f refer to multiple protrusions 9 within the same slot 3a, and are used in particular to identify the protrusions 9 within each slot 3a.

[0035] In the slot 3a having the power line 11, the power line 11 is formed by bending the first protrusion 9Aa for the power line, and the second to sixth protrusions 9b to 9f are positioned together with the power line 11 within the slot 3a.

[0036] A radial gap 13 is formed between the tip ends 10a of the protrusions 9 of adjacent layers. This gap 13 makes it easier to circumferentially bend the protrusions 9 in a later process. The gap 13 is defined by bending the protrusions 9 in the radial direction.

[0037] The protrusion 9 has bent portions 12a and 12b between the base end portion 10b, the tip end portion 10a, and the intermediate portion 10c. The base end portion 10b and the tip end portion 10a are aligned along the axial direction, and the intermediate portion 10c is inclined radially outward from the base end portion 10b toward the tip end portion 10a.

[0038] The distal end 10a and the proximal end 10b do not need to be strictly aligned with the axial direction, and may be slightly inclined. When the distal end 10a is slightly inclined with respect to the axial direction, the inclination of the intermediate portion 10c means that the intermediate portion 10c is more inclined than the distal end 10a.

[0039] [Apparatus and Method for Manufacturing Stator] FIG. 4 is a side view showing an apparatus for manufacturing a stator according to the first embodiment.

[0040] In this example, the stator 1 is manufactured using a manufacturing apparatus 15 shown in Fig. 4. The manufacturing apparatus 15 includes a robot manipulator 17 as a drive unit, a bending jig 19, a clamp 20 as a restraining body, a pusher 21, and a controller 31.

[0041] The robot manipulator 17 is, for example, a six-axis vertical articulated robot. A bending jig 19 serving as an end effector is attached to the end of the robot manipulator 17. Although only one robot manipulator 17 is shown in FIG. 4, a plurality of robot manipulators 17 may be provided in the circumferential direction of the stator 1.

[0042] The bending jig 19 is used to form the gaps 13 between the protrusions 9 of adjacent layers. The formation of the gaps 13 may be performed separately using different jigs, etc. The bending jig 19 may also be used to form the power lines 11.

[0043] The bending jig 19 includes a main body 23 and comb teeth 25 .

[0044] The main body 23 is, for example, a plate made of metal. Comb teeth 25 are provided on one side of the main body 23. The shape and material of the main body 23 can be set arbitrarily.

[0045] The comb teeth 25 include a plurality of teeth, three in this embodiment, 25a, 25b, and 25c, arranged at intervals in the axial direction of the sixth axis A6 of the robot manipulator 17. The teeth 25a, 25b, and 25c are formed in a plate shape.

[0046] The teeth 25a, 25b, and 25c extend in a direction away from the sixth axis A6 and have a single-edged pointed tip. These teeth 25a, 25b, and 25c are arranged along the axial direction of the stator core 3 with the alignment direction coinciding with the radial direction of the stator 1 in which the protrusions 9 are aligned within the slots 3a, and the single-edged inclined surface faces radially outward. In this state, the length of the teeth 25a gradually decreases in the axial direction from the radially inner tooth 25c to the outer tooth 25a.

[0047] The clamp 20 is formed into a plate shape, for example, from metal or the like. The clamp 20 grips the base end 10b of the protrusion 9 in the slot 3a from both the inside and outside in the radial direction. This gripping protects the insulating paper 22 between the slot 3a and the protrusion 9 and also forms a starting point for bending the protrusion 9. The clamp 20 of this embodiment restrains the base end 10b of the protrusion 9 from the radial direction and holds the base end 10b of the protrusion 9 in a state aligned with the axial direction of the stator core 3 when bending and unbending.

[0048] The pusher 21 is columnar and made of resin, etc. The pusher 21 is movable toward and away from the teeth 25a on the outside in a direction along the sixth axis A6 of the robot manipulator 17.

[0049] The movement direction of the pusher 21 is the radial direction, which is perpendicular to the axial direction, which is the direction in which the teeth 25a are inserted between the protrusions 9. However, the movement direction of the pusher 21 may be a direction inclined with respect to the radial direction and the sixth axis A6. Even when the movement direction of the pusher 21 is inclined with respect to the radial direction, the pusher 21 moves in the radial direction relative to the teeth 25a as long as there is a radial movement component.

[0050] The pusher 21 may be moved by an appropriate actuator such as a linear actuator, and the pusher 21 may be supported by the robot manipulator 17 or another member.

[0051] The controller 31 is composed of a computer having a processor, memory, etc. Note that the controller 31 is only conceptually shown in Fig. 4 .

[0052] The controller 31 controls the bending jig 19, i.e., the teeth 25a, 25b, and 25c, and the pusher 21 through the robot manipulator 17. Through this control, the manufacturing method of the stator 1 is realized.

[0053] Hereinafter, a method for manufacturing the stator 1 will be described, in which the controller 31 controls the manufacturing device 15 .

[0054] The method for manufacturing the stator 1 involves layer expansion, which involves expanding the gaps 13 between the protrusions 9 of adjacent layers within the slots 3a, as shown in FIGS.

[0055] 4, in this embodiment, the stator 1 is first held in a predetermined position and the axial direction of the stator core 3 is aligned in the vertical direction. At this time, the base ends of the protrusions 9 are gripped by the clamps 20. Specifically, the clamps 20 clamp the first to sixth protrusions 9a to 9f together from the inside and outside in the radial direction.

[0056] This provides protection for the insulating paper 22 and forms the starting point for bending the protrusion 9. Furthermore, the clamp 20 restrains the base end 10b of the protrusion 9 from the radial direction, and the base end 10b of the protrusion 9 is held in a state aligned with the axial direction of the stator core 3.

[0057] Before being bent, the first protrusion 9a to the sixth protrusion 9f are aligned along the axial direction as a whole, and the axial length gradually decreases from the first protrusion 9a to the sixth protrusion 9f within each slot 3a.

[0058] A bending jig 19 is positioned above the stator 1 by a robot manipulator 17. At this time, the teeth 25a, 25b, and 25c of the comb teeth 25 of the bending jig 19 are aligned along the axial direction, with the single-edged inclined surface facing outward in the radial direction of the stator core 3.

[0059] FIG. 5 is an enlarged side view showing the state at the start of bending the protruding portion.

[0060] 5, the bending jig 19 is moved relative to the stator core 3 and also moved radially. As a result, the tips of the teeth 25a, 25b, and 25c of the comb teeth 25 of the bending jig 19 are brought into radial contact with the protrusions 9 (the second, fourth, and sixth protrusions 9b, 9d, and 9f in this embodiment) located radially inward of each layer. This contact is performed based on the difference in axial length between the teeth 25a, 25b, and 25c and the difference in axial length between the protrusions 9.

[0061] As a result, the tips of the teeth 25a, 25b, and 25c of the comb tooth 25 are located between the protruding portions 9 of adjacent layers. That is, the tooth 25a is located between the second and third protruding portions 9b and 9c, the tooth 25b is located between the fourth and fifth protruding portions 9d and 9e, and the tooth 25c is located radially inward of the sixth protruding portion 9f.

[0062] FIG. 6 is an enlarged side view showing a state in which the teeth of the bending jig are being inserted into the protrusion.

[0063] 6, the bending jig 19 is further moved in the axial direction by the robot manipulator 17 toward the stator core 3. As a result, the teeth 25a and 25b of the comb teeth 25 are inserted between the protrusions 9 of adjacent layers, that is, between the second and third protrusions 9b and 9c, and between the fourth and fifth protrusions 9d and 9e.

[0064] During this insertion, the bending jig 19 is tilted around an axis perpendicular to the radial direction of the stator core 3, which is the arrangement direction of the teeth 25a, 25b, and 25c, and the axial direction of the stator core 3, in this embodiment, around the fifth axis A5 of the robot manipulator 17. As a result, the tips of the teeth 25a, 25b, and 25c of the comb teeth 25 are not in contact with the insulating layer of the protrusion 9.

[0065] FIG. 7 is an enlarged side view showing the state in which the teeth of the bending jig are inserted into the protrusion.

[0066] During the process of inserting the teeth 25a, 25b, and 25c, the bending jig 19 is moved by the robot manipulator 17 so that the teeth 25a, 25b, and 25c are again aligned along the axial direction as shown in FIG.

[0067] When the teeth 25a, 25b, and 25c of the comb teeth 25 are fully inserted between the layers, the third and fourth protrusions 9c and 9d are housed between the teeth 25a and 25b along the axial direction. The first and second protrusions 9a and 9b and the fifth and sixth protrusions 9e and 9f are slightly spread outward and inward in the radial direction by the teeth 25b and 25c, respectively. This spreading results in elastic deformation of the protrusions 9, but may also be plastic deformation.

[0068] In this state, teeth 25a and 25b are arranged on both radial sides of the tip end 10a of the third and fourth protrusions 9c and 9d. Note that the third protrusion 9c has the tooth 25a arranged on one radial side and the tooth 25b arranged on the other radial side, via the fourth protrusion 9d. The fourth protrusion 9d also has the tooth 25b arranged on one radial side and the tooth 25a arranged on the other radial side, via the third protrusion 9c.

[0069] Similarly, teeth 25b and 25c are arranged on both radial sides of the tip end 10a of the fifth and sixth protrusions 9e and 9f.

[0070] The teeth 25a are arranged on one radial side of the tip end 10a of the first and second protrusions 9a and 9b. The teeth 25a are arranged adjacent to the second protrusion 9b on one radial side, and the teeth 25b are arranged on one radial side of the first protrusion 9a, with the second protrusion 9b interposed therebetween.

[0071] 8A is an enlarged side view showing the bending of the protrusion, and FIG. 8B is an enlarged view showing the protrusion of FIG. 8A.

[0072] 8A and 8B, the bending jig 19 is moved radially outward by the robot manipulator 17. As a result, the tip end 10a of the protrusion 9 of the stator core 3 is displaced radially outward of the stator core 3, and the protrusion 9 is bent so as to be positioned at the first position.

[0073] Depending on the specifications of the stator core 1, the bending jig 19 may be moved radially inward. In this case, the tip end 10 a of the protrusion 9 is moved radially inward and bent. Therefore, the bending of the protrusion 9 may be performed by moving the tip end 10 a either radially inward or radially outward.

[0074] The first position is a position radially outward from the second position, and the second position is radially outward from the initial position. When the tip portion 10a is aligned in the axial direction in both cases, the first and second positions can be simply considered in terms of the position of the tip portion 10a. In this case, the second position is the position of the tip portion 10a of the protrusion 9 where it should be positioned for subsequent processing, and the first position is a position where the tip portion 10a is displaced excessively in the radial direction beyond the second position relative to the initial position. Therefore, the bending amount of the tip portion 10a at the first position is excessive compared to the second position. Note that when the tip portion 10a is inclined together with the intermediate portion 10c at the first position and the tip portion 10a is aligned in the axial direction at the second position, the first and second positions can be considered in terms of the inclination amount of the intermediate portion 10c. The position where the inclination amount of the intermediate portion 10c is relatively large is the first position, and the position where the inclination amount of the intermediate portion 10c is relatively small is the second position. The amount of inclination can be the angle formed between the axial direction and the intermediate portion 10c.

[0075] During bending, the base end portions 10b of the first to sixth protruding portions 9a to 9f are held by the clamps 20 in a state aligned along the axial direction of the stator core 3. Furthermore, the tip end portions 10a of the third to sixth protruding portions 9c to 9f are held in a state aligned along the axial direction by the teeth 25a to 25c on both sides in the radial direction.

[0076] Therefore, the third to sixth protrusions 9c to 9f are bent so that the bent portions 12a and 12b are formed between the distal end 10a and the proximal end 10b along the axial direction and the inclined intermediate portion 10c. The inclination of the intermediate portion 10c is inclined outward from the proximal end 10b toward the distal end 10a.

[0077] On the other hand, since the first and second protrusions 9a and 9b do not have teeth on the radially outer side, the bent portion 12a is formed between the base end 10b and the intermediate portion 10c when the first and second protrusions 9a and 9b are bent. As a result, the first and second protrusions 9a and 9b are inclined as a whole from the intermediate portion 10c to the tip end 10a.

[0078] FIG. 9 is an enlarged side view showing additional bending of the protrusion.

[0079] 9, the tip portions 10a of the first and second protrusions 9a and 9b are pressed against the teeth 25a from the outside in the radial direction by the pusher 21. As a result, the tip portions 10a of the first and second protrusions 9a and 9b are additionally bent to be aligned in the axial direction.

[0080] Thereafter, the pusher 21 is moved away from the tip end portions 10a of the first and second protrusions 9a and 9b, and the bending is performed.

[0081] 10 is an enlarged side view showing the protrusion 9 bent back. For details of the protrusion 9, refer to FIG.

[0082] 10 and 3, the bending jig 19 is moved radially inward by the robot manipulator 17. This bends back the bent portions 12a and 12b of the protrusion 9 so that the tip 10a of the protrusion 9 is positioned at the second position.

[0083] The radially inward movement of the bending jig 19 may involve moving the bending jig 19 only in the radial direction, or may involve moving the bending jig 19 in both the radial and axial directions. When moving the bending jig 19 in both the radial and axial directions, the bending jig 19 may be moved in a diagonal straight line or in an arc.

[0084] The bending back refers to bending (plastically deforming) the bent portions 12 a and 12 b inward in the opposite radial direction, thereby reducing the amount of bending outward in the radial direction. The bending amount can be thought of as the radial dimension between the distal end portion 10 a and the proximal end portion 10 b.

[0085] When the tip portion 10a is bent radially inward, it is bent back by bending it radially outward in the opposite direction. Therefore, the bending back only needs to move the tip portion 10a toward the other of the radially inward and outward directions. The other of the radially inward and outward directions is the opposite direction to the radially inward and outward direction.

[0086] In this embodiment, bending back is performed while maintaining the base end 10 b and the tip end 10 a in an axially aligned state. Specifically, the tip ends 10 a of the first and second protrusions 9 a and 9 b abut against the tooth 25 a in the radial direction, the tip ends of the third and fourth protrusions 9 c and 9 d are held between the teeth 25 a and 25 b, and the tip ends of the fifth and sixth protrusions 9 e and 9 f are held between the teeth 25 b and 25 c.

[0087] In this embodiment, this bending back suppresses springback of the protrusion 9 located at the second position, thereby suppressing variations in the position of the tip end 10a. Note that the tip end 10a of the first and second protrusions 9a and 9b on the radially outer side undergoes a bending back operation, but does not undergo bending back (plastic deformation). The first and second protrusions 9a and 9b undergo a larger amount of plastic deformation than the other protrusions 9, and are bent while being tightly sandwiched between the pusher 21 and the teeth 25a. For this reason, the tip end 10a of the first and second protrusions 9a and 9b has a stable amount of springback and is stable in position.

[0088] In this way, bending back with plastic deformation is performed on at least some of the protrusions 9. However, bending back with plastic deformation may be performed on all of the protrusions 9. The displacement of the tip ends 10a of the protrusions 9 to the first position may also be performed on at least some of the protrusions 9 that are to be bent back with plastic deformation.

[0089] After the bending back is completed in this manner, the bending jig 19 is displaced in the axial direction by the robot manipulator 17 so as to move away from the stator core 3, and the comb teeth 25 are pulled out from the protruding portion 9. This completes the expansion of the interlayer space of the protruding portion 9.

[0090] As described above, in this embodiment, the protruding portions 9 of the stator core 3 are bent so that the tip ends 10a of the protruding portions 9 are displaced radially outward of the stator core 3 and positioned at a first position. Then, the bent portions of the protruding portions 9 are bent back so that the tip ends 10a of the bent protruding portions 9 are displaced radially inward and positioned at a second position.

[0091] As a result, in this embodiment, springback of the tip 10 a of the protrusion 9 disposed at the second position can be suppressed, and the position of the tip 10 a can be stabilized, which makes it easier to process the protrusion 9 in a subsequent process.

[0092] The bending and unbending are performed with the base end 10b and the tip end 10a of the protrusion 9 aligned with the axial direction of the stator core 3. Therefore, the bending can be reliably performed at the bent portions 12a and 12b between the base end 10b and the tip end 10a and the intermediate portion 10c. Furthermore, since the tip end 10a of the protrusion 9 is ultimately positioned along the axial direction, the position can be more reliably stabilized by bending it back while maintaining that final position.

[0093] The first and second protrusions 9a and 9b are bent with the tip end 10a aligned with the intermediate portion, and after bending, the tip end 10a is additionally bent relative to the intermediate portion 10c to be aligned with the axial direction. Therefore, even if the first and second protrusions 9a and 9b are located on the radially outer side, the application of inadvertent force during bending can be suppressed, and the tip end 10a can be reliably aligned with the axial direction by the additional bending.

[0094] 11 is an enlarged side view showing bending back of a protrusion in a method for manufacturing a stator according to Example 2 of the present invention. Note that Example 2 has a basic configuration in common with Example 1, and therefore, components corresponding to those in Example 1 are designated by the same reference numerals and redundant description will be omitted.

[0095] In the second embodiment, as shown in FIG. 11, the pusher 21 that has been additionally bent is unbent without being separated from the tip end portions 10a of the first and second protrusions 9a and 9b.

[0096] The process up to the additional bending of the first and second protrusions 9a and 9b by the pusher 21 is the same as in Example 1, so refer to Example 1. Also, refer to Figure 3 for details of the protrusions 9 when they are unbent.

[0097] To unbend the protrusion 9, the bending jig 19 is moved radially inward by the robot manipulator 17, and the pusher 21 is moved to follow the teeth 25a. As a result, the bent portions 12a and 12b of the protrusion 9 are unbent so that the tip 10a of the protrusion 9 is positioned at the second position.

[0098] In this embodiment, in addition to the effects of the first embodiment, the first and second protrusions 9a and 9b can be bent back. As a result, in this embodiment, the position of the tip 10a can be more reliably stabilized.

[0099] Fig. 12 is an enlarged side view showing bending back the protrusion in a method for manufacturing a stator according to a third embodiment of the present invention. Fig. 13 is an enlarged side view showing additional bending of the protrusion after bending back the protrusion in Fig. 12. Note that, since the third embodiment has a basic configuration in common with the first embodiment, components corresponding to those in the first embodiment are designated by the same reference numerals, and redundant description will be omitted.

[0100] In this embodiment, as shown in FIGS. 12 and 13, after the bending back, the first and second protruding portions 9a and 9b are additionally bent.

[0101] The process up to the bending of the first to sixth protruding portions 9a to 9f is the same as in Example 1, so Example 1 will be referred to.

[0102] After bending, the first to sixth protruding portions 9a to 9f are bent back as shown in Fig. 12. When bending back, the bending jig 19 is moved radially inward by the robot manipulator 17. As a result, the third to sixth protruding portions 9c to 9f are bent back in the same manner as in Example 1, and the first and second protruding portions 9a and 9b are bent back with the tip portions 10a aligned with the middle portions 10c.

[0103] 13, the first and second protrusions 9a and 9b are additionally bent by the pusher 21. That is, the tip portions 10a of the first and second protrusions 9a and 9b are pressed against the teeth 25a from the outside in the radial direction by the pusher 21. As a result, the tip portions 10a of the first and second protrusions 9a and 9b are additionally bent to be aligned in the axial direction.

[0104] The bent portions 12a and 12b (see Figure 3) between the tip end 10a and the middle portion 10c of the first and second protrusions 9a and 9b have less spring back than the bent portion between the base end 10b and the middle portion 10c, and do not need to be bent back.

[0105] Thereafter, the pusher 21 is moved away from the tip ends 10a of the first and second protrusions 9a and 9b. Then, the bending jig 19 is moved axially by the robot manipulator 17 so as to move away from the stator core 3. In this way, the interlayer widening of the protrusions 9 is completed.

[0106] In this embodiment, the same effects as those in the first embodiment can be achieved.

[0107] DESCRIPTION OF SYMBOLS 1 stator 3 stator core 5 stator coil 7 segment coil 9 protruding portion 10a tip portion 10b base end portion 10c middle portion 15 manufacturing device 17 robot manipulator (driving portion) 20 clamp (restraint body) 21 pusher 25a, 25b, and 25c teeth

Claims

1. A method for manufacturing a stator, comprising: displacing a tip of a protrusion of a segment coil held by a stator core toward one of the radially outward and inward sides of the stator core, bending the protrusion so that it is located at a first position; and displacing the tip of the bent protrusion toward the other of the radially outward and inward sides, and bending the bent portion of the protrusion back so that it is located at a second position, one of the radially outward and inward sides, rather than its initial position before bending.

2. A method for manufacturing a stator as claimed in claim 1, wherein the bending and unbending are performed with the base end of the protrusion aligned in the axial direction of the stator core.

3. A method for manufacturing a stator according to claim 2, wherein the bending and unbending are performed with the tip of the protrusion aligned in the axial direction.

4. A method for manufacturing a stator as claimed in claim 2, wherein the bending and the bending back are performed with the tip portion aligned with the middle portion, and after the bending back, the tip portion is additionally bent with respect to the middle portion to be aligned with the axial direction.

5. A method for manufacturing a stator as claimed in claim 2, wherein the bending is performed with the tip portion aligned with the intermediate portion, and after the bending, the tip portion is additionally bent with respect to the intermediate portion so as to be aligned with the axial direction, and the bending back is performed with the tip portion aligned with the axial direction.

6. A stator manufacturing device which bends a protrusion of a segment coil held in a stator core relative to the stator core, comprising: teeth arranged on at least one radial side of the stator core relative to a tip of the protrusion; and a drive unit which moves the teeth in the radial direction to displace the tip of the protrusion in the radial direction, bending the tip of the protrusion toward one of the radially outward and inward sides so that it is positioned in a first position; and displacing the tip of the bent protrusion toward the other of the radially outward and inward sides so that it is positioned in a second position that is closer to one of the radially outward and inward sides than its initial position before bending.

7. A stator manufacturing apparatus according to claim 6, comprising a restraining body that restrains the base end of the protrusion from the radial direction and holds the base end of the protrusion in a state aligned with the axial direction of the stator core during the bending and unbending.

8. A stator manufacturing apparatus as claimed in claim 7, wherein the teeth are arranged on both radial sides of the tip of the protrusion, and the teeth on both radial sides hold the tip of the protrusion in a state aligned with the axial direction during the bending and unbending.

9. A stator manufacturing apparatus as claimed in claim 7, further comprising a pusher movable in the radial direction relative to the teeth, wherein the bending and unbending are performed by moving the teeth in the radial direction so that the tip portion is aligned with the middle portion, and after unbending, the pusher presses the tip portion against the teeth, and additionally bends the tip portion against the middle portion to be aligned with the axial direction.

10. A stator manufacturing apparatus as claimed in claim 7, further comprising a pusher movable in the radial direction relative to the teeth, wherein the bending is performed by moving the teeth towards one of the radially outward and inward directions so that the tip is aligned with the middle portion, and after the bending, the tip is pressed against the teeth by the pusher and the tip is additionally bent against the middle portion so that it is aligned with the axial direction, and the bending back is performed by moving the teeth towards the other radially outward and inward direction so that the tip is aligned with the axial direction.

11. The stator manufacturing apparatus according to claim 10, wherein the bending back is performed while the pusher is moved together with the teeth and pressed against the teeth at the tip end.

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