Jig and device for stator twisting

Abstract

Provided is a jig for stator twisting, with which it is possible to easily suppress radial-direction deformation of a projecting portion of a segment coil that projects from a stator core during twisting. A jig 9A for twisting a stator 1, in which projecting portions 7A that include coil ends 7a of a segment coil 7 held by a stator core 3 are bent in a circumferential direction by twisting, comprises: a twisting member 13 having a grasping portion 17 that grasps and displaces the coil ends 7a in an axial direction and a circumferential direction relative to the stator core 3 so as to bend the projecting portions 7A; and a restraint wall 31 which is supported so as to be movable in an axial direction on a radially outer side with respect to the twisting member 13 and which restrains the projecting portions 7A on the radially outer side during bending in the state of projecting in an axial direction with respect to the grasping portion 17.

Description

Stator twisting jig and device

[0001] The present invention relates to a twisting jig and device for a stator of a rotating electrical machine such as a motor or a generator.

[0002] A conventional stator twisting device is, for example, a stator manufacturing device described in Patent Document 1.

[0003] This manufacturing equipment includes an inner conductor bending mold and an outer conductor bending mold, which correspond to the inner conductor protrusions and outer conductor protrusions, respectively, that are the portions of the segment coil that protrude from the stator core. A partition wall is provided between these inner conductor protrusions and outer conductor protrusions.

[0004] When using this manufacturing apparatus, the inner and outer restraint walls are disposed radially inside and outside the inner and outer conductor extensions, respectively. Then, the inner and outer conductor bending dies are lowered while inserting the partitions into the radial spaces between the inner and outer conductor extensions. The inner and outer conductor bending dies are rotated in opposite directions to each other, bending the inner and outer conductor extensions in the circumferential direction.

[0005] At this time, the inner and outer restraint walls and the partition wall prevent the inner and outer conductor protruding portions from falling in the radial direction, thereby preventing damage to the insulating layers of the inner and outer conductor protruding portions.

[0006] However, with such a manufacturing device, when the inner and outer conductor protrusions are lowered, separate inner and outer restraint walls must be placed on the inside and outside of the inner and outer conductor protrusions, which makes the operation time-consuming.

[0007] Japanese Patent Application Laid-Open No. 2018-170910

[0008] The problem to be solved is that it takes time and effort to prevent the protruding portions of the segment coils protruding from the stator core from deforming in the radial direction during twisting processing.

[0009] The present invention provides a stator twisting jig for twisting a protruding portion of a stator core, including a coil end of a segment coil held in the stator core, in a circumferential direction by twisting. The twisting jig includes a twisting member having a gripping portion that grips the coil end and displaces it axially and circumferentially relative to the stator core to bend the protruding portion, and a restraining wall that is supported radially outside or inside the twisting member so as to be movable in the axial direction and that restrains the protruding portion on the radial outside or inside during bending in a protruding state relative to the gripping portion.

[0010] The present invention also provides a twisting device equipped with the twisting jig.

[0011] According to the present invention, it is possible to easily prevent the protruding portions of the segment coils protruding from the stator core from being deformed in the radial direction during twisting processing.

[0012] FIG. 1 is a perspective view of a stator according to an embodiment of the present invention after bending of the protruding portions. FIG. 2 is a perspective view of a stator before bending of the protruding portions. FIG. 3 is a schematic perspective view of a first twisting jig according to an embodiment of the present invention, with the first constraint wall in a retracted state. FIG. 4 is a schematic perspective view of the first constraint wall of the first twisting jig of FIG. 3 in a protruding state. FIGS. 5(A) and 5(B) are cross-sectional views showing a state in which the first twisting jig of FIG. 3 is disposed relative to the stator, with FIG. 5(A) showing the state before twisting and FIG. 5(B) showing the state after twisting. FIG. 6 is an enlarged cross-sectional view of a portion of FIG. 5(A). FIG. 7 is an enlarged cross-sectional view of a portion of FIG. 5(B). FIG. 8 is a schematic perspective view of a second twisting jig according to an embodiment of the present invention, with the second constraint wall in a retracted state. FIG. 9 is a schematic perspective view of the second twisting jig according to FIG. 8, with the second constraint wall in a protruding state. 10(A) and (B) are cross-sectional views showing a state in which the second twisting jig is disposed relative to the stator, with Fig. 10(A) being the state before twisting and Fig. 10(B) being the state after twisting. Fig. 11 is an enlarged cross-sectional view showing a portion of Fig. 10(A). Fig. 12 is an enlarged cross-sectional view showing a portion of Fig. 10(B).

[0013] The objective of easily preventing the protruding portion of the segment coil protruding from the stator core from deforming radially during twisting is achieved by supporting a restraint wall so that it can move axially relative to the gripping portion that grips the protruding portion during twisting.

[0014] That is, the twisting jig 9 (9A and 9B) is a twisting jig for the stator 1 in which the protruding portion 7A relative to the stator core 3, including the coil end 7a of the segment coil 7 held in the stator core 3, is bent circumferentially by twisting.

[0015] This twisting jig 9 includes twisting members 13, 15, 41, and 43 and restraining walls 31 and 59. The twisting members 13, 15, 41, and 43 have gripping portions 17, 19, 45, and 47 that grip the coil end 7a and bend the protruding portion 7A by displacing it in the axial and circumferential directions relative to the stator core 3. The restraining walls 31 and 59 are supported radially outward or inward relative to the twisting members 13, 15, 41, and 43 so as to be axially movable, and restrain the protruding portion 7A radially outward or inward when bending it in a protruding state relative to the gripping portions 17, 19, 45, and 47.

[0016] The twist members 13 , 15 , 41 , and 43 may be circular, and the restraining walls 31 and 59 may be circular and positioned radially outward or inward relative to the twist members 13 , 15 , 41 , and 43 .

[0017] The restraining walls 31 and 59 may abut against the stator core 3 in the axial direction during the twisting process, and the gripping portions 17, 19, 45, and 47 may move in the axial direction relative to the restraining walls 31 and 59 abutting against the stator core 3 during the twisting process.

[0018] The twisting jig 9 may include biasing members 37 and 65 that bias the restraining walls 31 and 59 in the axial direction to maintain the protruding state relative to the gripping portions 17 , 19 , 45 , and 47 .

[0019] The twist members 13, 15, 41, and 43 may include outer members 13 and 41 and inner members 15 and 43 that are positioned radially outward and inward and rotate in opposite directions to each other to bend the protrusion 7A in opposite circumferential directions. In this case, the restraint walls 31 and 59 may be disposed radially outward of the outer members 13 and 41 or radially inward of the inner members 15 and 43.

[0020] The twisting device is equipped with such a twisting jig 9 and twists the protruding portion 7A of the segment coil 7.

[0021] [Stator] Fig. 1 is a perspective view of a stator according to an embodiment of the present invention, showing the protrusions after bending, and Fig. 2 is a perspective view of the stator before bending.

[0022] 1 and a rotor (not shown) constitute a rotating electric machine. 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.

[0023] 1 and 2 show a state in which the stator coils 5 are assembled into the stator core 3 and supported by a support jig 6. In the state shown in Fig. 1, protrusions 7A including the coil ends 7a of each segment coil 7 protrude in the axial direction from the stator core 3, are arranged circumferentially, and are bent in the circumferential direction. In the state shown in Fig. 2, the protrusions 7A extend along the axial direction without being bent in the circumferential direction.

[0024] The axial direction and the circumferential direction respectively refer to the direction along the axis and the outer periphery of the stator 1. The radial direction refers to the direction along the diameter of the stator 1. The up and down refer to the up and down in the direction of gravity.

[0025] The coil ends 7a are joined by welding each set of radially adjacent coil ends 7a together. As a result, the plurality of segment coils 7 collectively form the stator coil 5. The coil ends 7a are then coated with an insulating paint, and the stator coil 5 is sealed with resin, etc., to form the stator 1 for the rotating electric machine. For convenience in the following explanation, the one shown in Figures 1 and 2 will be referred to as the stator 1.

[0026] The stator core 3 of the stator 1 is formed by laminating, for example, a plurality of annular electromagnetic steel plates, silicon steel plates, etc. The stator coil 5 is provided in three phases on the stator core 3 and is configured to be wave-wound.

[0027] The stator core 3 has a plurality of slots 3 a arranged at equal intervals in the circumferential direction. Segment coils 7 are inserted into the slots 3 a. As a result, the segment coils 7 are held in the stator core 3.

[0028] Each segment coil 7 is formed in a U-shape, for example, a hairpin shape. Multiple segment coils 7 are combined in the circumferential direction around the stator core 3. These segment coils 7 are arranged along the circumferential direction, and are shifted to the adjacent layer at the apex of the hairpin shape. The apex is located on the underside of Figures 1 and 2 and is not shown in Figures 1 and 2.

[0029] 1 and 2, the segment coil 7 is formed, for example, from a rectangular wire having a rectangular cross section with a predetermined aspect ratio. However, the cross-sectional shape of the segment coil 7 is not particularly limited. This segment coil 7 has a protruding portion 7A, including coil ends 7a without an insulating layer, protruding from the stator core 3. An insulating layer is formed on the entire segment coil 7A except for the coil ends 7a.

[0030] The protrusion 7A is twisted and bent as shown in Figure 1. The protrusion 7A includes portions that are inclined with respect to the axial and circumferential directions. Therefore, before bending as shown in Figure 2, the protrusion 7A corresponds to the tip region of the hairpin-shaped leg of the segment coil 7 where bending is performed.

[0031] The protrusions 7A are arranged in the circumferential direction, and in this figure they are arranged in six layers in the radial direction. The protrusions 7A are twisted in opposite directions in the circumferential direction, with each set consisting of two inner and outer layers, from the first layer at the outermost periphery to the sixth layer at the innermost periphery. In each set of two inner and outer layers, the coil ends 7a of the protrusions 7A are joined by welding. The number of layers of the protrusions 7A is set appropriately depending on the characteristics of the stator 1, etc.

[0032] [Twisting Device for Stator] In this embodiment, the twisting device for the stator 1 bends the protruding portion 7A, which protrudes in the axial direction from the stator core 3 as shown in FIG. 2 before being twisted, in the circumferential direction as shown in FIG.

[0033] Although not shown as a whole, the twisting device of this embodiment includes a plurality of twisting jigs 9. The twisting jigs 9 are provided for each of the inner and outer radial layers of the sets of protrusions 7A. In this embodiment, only the first twisting jig 9A (FIGS. 3 to 7) for the outermost set of protrusions 7A and the second twisting jig 9B (FIGS. 8 to 12) for the innermost set of protrusions 7A will be described.

[0034] The twisting device also includes a lifting mechanism, a rotation mechanism, a jig exchange mechanism, a control device, and the like, all of which are not shown. The lifting mechanism is configured to displace the twisting jig 9 up and down relative to the stator 1. The rotation mechanism is configured to rotate the twisting jig 9 (twist ring, described later). The jig exchange mechanism is configured to exchange multiple twisting jigs 9 for different layers and position them on the stator 1. The control device is configured by a computer, and controls each part of the twisting device to perform twisting. This twisting device performs bending on different sets of protrusions 7A while exchanging between multiple twisting jigs 9.

[0035] [First twist jig] Fig. 3 is a schematic perspective view showing the first twist jig according to this embodiment with the first restraint wall in a retracted state. Fig. 4 is a schematic perspective view showing the protruding state of the first restraint wall of the first twist jig of Fig. 3. Figs. 5(A) and (B) are cross-sectional views of the first twist jig of Fig. 3 placed relative to the stator, Fig. 5(A) showing the state before twisting, and Fig. 5(B) showing the state after twisting. Fig. 6 is an enlarged cross-sectional view showing a portion of Fig. 5(A). Fig. 7 is an enlarged cross-sectional view showing a portion of Fig. 5(B).

[0036] As shown in FIGS. 3 to 7, the first twist jig 9A includes a first twist ring 13 which is an outer member of the twisting member, a second twist ring 15 which is an inner member thereof, and a first restraining wall 31.

[0037] The first twist ring 13 twists the group of protrusions 7A arranged in the first layer on the outermost periphery of the stator 1 in one circumferential direction. The second twist ring 15 twists the group of protrusions 7A arranged in the second innermost layer on the outermost periphery in the opposite circumferential direction relative to the group of protrusions 7A in the first layer.

[0038] The first twist ring 13 and the second twist ring 15 are cylindrical with different outer diameters and are concentrically assembled. However, the twist members do not have to be cylindrical like the first twist ring 13 and the second twist ring 15, and may be arc-shaped in plan view. Furthermore, the twist members may be formed by arranging multiple arc-shaped members in the circumferential direction to form a discontinuous circular shape. The first twist ring 13 and the second twist ring 15 can also be used independently.

[0039] The first and second twist rings 13 and 15 are rotatable relative to each other in the circumferential direction. The first and second twist rings 13 and 15 each have an outer gripping portion 17 and an inner gripping portion 19 as gripping portions for gripping the protruding portion 7A. The outer gripping portion 17 and the inner gripping portion 19 are formed in a comb-teeth shape at the lower ends of the first and second twist rings 13 and 15, respectively. Note that the outer gripping portion 17 and the inner gripping portion 19 do not need to be comb-teeth shaped as long as they can grip the protruding portion 7A, but it is preferable that they be shaped so that the protruding portion 7A is inserted in the axial direction.

[0040] An outer drive cylinder 21 is integrally provided on the upper end of the first twist ring 13. An inner drive cylinder 23 is integrally provided on the upper end of the second twist ring 15. Engagement portions 25 and 27 for rotational drive are formed on the outer drive cylinder 21 and the inner drive cylinder 23. The outer drive cylinder 21 is provided with a flange 29 for attachment to a jig exchange mechanism.

[0041] A first restraint wall 31 is supported on the radially outer side of the first twist ring 13 so as to be movable in the axial direction. The axial movement of the first restraint wall 31 occurs between a retracted state and a protruding state. The retracted state of the first restraint wall 31 is a state in which the first restraint wall 31 is retracted so as to be pressed into the first twist ring 13 in the axial direction. The protruding state of the first restraint wall 31 is a state in which the first restraint wall 31 protrudes relative to the first twist ring 13. Note that another restraint wall can also be added inside the second twist ring 15.

[0042] The first restraint wall 31 of this embodiment has a circular shape, particularly a cylindrical shape, and is concentrically fitted to the first twist ring 13. Note that the restraint wall does not need to be cylindrical like the first restraint wall 31, and may be arc-shaped in plan view. Furthermore, the restraint wall may be a discontinuous circular shape formed by arranging multiple arc-shaped walls in the circumferential direction.

[0043] This first restraining wall 31 restrains the protruding portion 7A at the radially outer side when bending, in a protruding state in the axial direction relative to the outer gripping portion 17 of the first twist ring 13 by moving in the axial direction. The restraint is performed to a degree that prevents the protruding portion 7A from falling in the radial direction when bending the protruding portion 7A and suppresses deformation such as escaping and bulging outward in the radial direction.

[0044] Such restraint is performed at least up to the bending position 7Aa (see FIG. 1) above the deformation of the protrusion 7A. Preferably, the restraint is performed up to the upper bending position 7Aa and the upper bending position 7Ab. Note that, in order to suppress deformation in which the protrusion 7A escapes radially outward and bulges, it is preferable to perform the restraint so as to reduce the gap through which the protrusion 7A escapes as much as possible.

[0045] A guide slope 31c is formed on the inner periphery of the lower end of the first restraint wall 31. The lower end of this first restraint wall 31 abuts against a first stopper 39 (described later), and in this state the first restraint wall 31 restrains the protruding portion 7A.

[0046] A radial flange 31b is formed at the upper end of the first restraint wall 31. The flange 31b protrudes radially outward from the first restraint wall 31 and faces the lower surface of the outer drive barrel 21. A first guide pin 33 is provided between the flange 31b and the outer drive barrel 21.

[0047] The first guide pin 33 supports the first restraint wall 31 relative to the first twist ring 13 and guides the axial movement of the first restraint wall 31. The first guide pin 33 is fixed with its upper end inserted into the pin mounting hole 21 a of the outer drive barrel 21.

[0048] The first guide pin 33 passes through the flange 31b of the first restraint wall 31. A circular first coupling ring 35 is coupled to the lower end of the first guide pin 33. The first coupling ring 35 is disposed around the outer periphery of the first restraint wall 31 and fits loosely. Instead of the first coupling ring 35, a retaining member such as a nut may be attached to the lower end of the first guide pin 33.

[0049] The first guide pin 33 is inserted through a first coil spring 37 serving as a biasing member. The biasing member is not limited to a coil spring, and may be other elastic material such as rubber. The first coil spring 37 is provided between the first twist ring 13 (outer drive barrel 21) and the first restraint wall 31 (flange 31b) and biases the first restraint wall 31 in the axial direction. This biasing force keeps the restraint wall 31 protruding from the outer grip portion 17.

[0050] These sets of first guide pins 33 and first coil springs 37 are arranged at a plurality of locations on the first restraining wall 31 at equal intervals in the circumferential direction, and are attached in the same structure.

[0051] The first stopper 39 receives the lower end of the first restraint wall 31 in the axial direction and allows relative rotation in the circumferential direction. The first stopper 39 is disposed on the stator core 3 as a processing jig separate from the first twisting jig 9A. The first stopper 39 may also be configured with a roller bearing or the like. The first stopper 39 may be omitted. In this case, a roller may be attached to the lower end of the first restraint wall 31.

[0052] The first restraint wall 31 moves when the outer gripping portion 17 of the first twist ring 13 grips the coil end 7a of the protruding portion 7A and displaces it in the circumferential direction. The lower end of this first restraint wall 31 can be smoothly guided in the circumferential direction toward the stator core 3 by a first stopper 39. The first stopper 39 can also be substituted by a jig used to bend the protruding portion 7A in the radial direction before twisting it.

[0053] [Second twist jig] Figure 8 is a schematic perspective view showing a second twist jig used in a stator twisting device according to an embodiment of the present invention, with the second constraint wall in a retracted state. Figure 9 is a schematic perspective view showing the second twist jig of Figure 8, with the second constraint wall in a protruding state. Figures 10(A) and (B) are cross-sectional views showing a state in which the second twist jig is positioned relative to the stator, with Figure 10(A) showing the state before twisting and Figure 10(B) showing the state after twisting. Figure 11 is an enlarged cross-sectional view showing a portion of Figure 10(A). Figure 12 is an enlarged cross-sectional view showing a portion of Figure 10(B).

[0054] As shown in FIGS. 8 to 12, the second twisting jig 9B has substantially the same structure as the first twisting jig 9A, and includes cylindrical third twisting ring 41 and fourth twisting ring 43 as circular twisting members.

[0055] The third twist ring 41 and the fourth twist ring 43 are formed by twisting the protrusions 7A arranged in the fifth and sixth layers of the stator 1 in the opposite circumferential direction. The third and fourth twist rings 41 and 43 correspond to the first and second twist rings 13 and 15, and have comb-tooth-shaped outer gripping portions 45 and inner gripping portions 47 at their respective lower ends.

[0056] An outer drive cylinder 49 and an inner drive cylinder 51 are integrally provided on the upper ends of the third twist ring 41 and the fourth twist ring 43, respectively, and engagement portions 53 and 55 for rotational drive are formed on the outer drive cylinder 49 and the inner drive cylinder 51. The outer drive cylinder 49 is provided with a flange 57 for attachment to the jig exchange mechanism.

[0057] A circular second restraint wall 59 is supported radially inward of the fourth twist ring 43 so as to be axially movable. The structure of the second restraint wall 59 corresponds to that of the first restraint wall 31. However, the radial orientation of the first restraint wall 31 on the radially outer side differs from that of the second restraint wall 59 on the radially inner side.

[0058] This second restraining wall 59 restrains the protruding portion 7A radially inward when bending, in a protruding state in which it protrudes axially relative to the inner gripping portion 47 of the fourth twist ring 13 by moving in the axial direction. The restraint is performed to a degree that prevents the protruding portion 7A from falling in the radial direction when bending the protruding portion 7A and suppresses deformation such as escaping radially inward and bulging.

[0059] The restraint range of the second restraint wall 59, as in the case of the first restraint wall 31, is the bending position 7Aa above the deformation of the protrusion 7A, preferably between the upper and lower bending positions 7Aa and 7Ab, more preferably up to the lower bending position 7Ab, and even more preferably the entire axial range of the protrusion 7A.

[0060] In this embodiment, a guide slope 59c is formed on the outer periphery of the lower end of the second restraint wall 59. The lower end of this second restraint wall 59 abuts against a second stopper 67 (described later), so that the second restraint wall 59 restrains the entire axial area of ​​the protruding portion 7A.

[0061] A radially inward flange 59b is formed at the upper end of the second restraint wall 59, and the flange 59b faces the underside of the inner drive cylinder 51. A second guide pin 61 and a second coil spring 65 are disposed between the fourth twist ring 43 (inner drive cylinder 51) and the second restraint wall 59 (flange 59b). The second guide pin 61 is attached to the pin attachment hole 51a of the inner drive cylinder 51 and passes through the flange 59b of the second restraint wall 59. A second connecting ring 63 having an annular shape is connected to the lower end of the second guide pin 61.

[0062] The second guide pins 61 and the second coil springs 65 are arranged at a plurality of locations at equal intervals around the circumference of the second restraint wall 59 and are attached in a similar manner. Note that a separate restraint wall may be added to the outside of the third twist ring 41.

[0063] [Twisting Process] In twisting the stator 1, first, the stator 1 fixed and supported by the support jig 6 is set in a twisting device as shown in Fig. 2. In this embodiment, a jig exchange mechanism sequentially places a plurality of twisting jigs 9 on the stator 1, and sequentially bends the protruding portions 7A of the first to sixth layers in the circumferential direction.

[0064] When placing the first twist jig 9A on the stator 1, the first stopper 39 is placed on the stator core 3. In this state, the first twist jig 9A is lowered toward the stator 1 by the lifting mechanism. Alternatively, the stator 1 may be raised. Alternatively, the first twist jig 9A may be lowered while the stator 1 is raised.

[0065] 5A and 6, the coil ends 7a of the protruding portions 7A of the first layer on the outermost periphery are inserted between the comb teeth of the outer gripping portion 17. At the same time, the coil ends 7a of the protruding portions 7A of the second layer are inserted between the comb teeth of the inner gripping portion 19. This insertion completes the attachment of the first twisting jig 9A to the stator 1.

[0066] During this installation, the first restraint wall 31 is positioned around the outer periphery of the group of protruding portions 7A of the first layer. That is, the first restraint wall 31, which is protruding from the outer grip portion 17, moves down together with the first twist ring 13 and is positioned around the outer periphery of the group of protruding portions 7A of the first layer.

[0067] In this state, the lower end of the first restraint wall 31 abuts against the first stopper 39 in the axial direction. Note that the first restraint wall 31 may be arranged with an initial gap in the axial direction relative to the first stopper 39 when the first twisting jig 9A is attached to the stator 1.

[0068] The first restraint wall 31 may be locked in the retracted state and then unlocked and moved to the protruding state when the first twist jig 9A is attached to the stator 1. This movement may be achieved by the bias of the first coil spring 37, or by its own weight when the first coil spring 37 is omitted. The lock may be any mechanism that prevents the first restraint wall 31 from moving to the protruding state, and a well-known locking mechanism may be used, and the locking mechanism may be released manually or automatically.

[0069] Next, the first twist ring 13 for the first layer and the second twist ring 15 for the second layer are driven by the rotation drive mechanism to rotate in opposite circumferential directions. At the same time, the lifting mechanism is controlled to lower the first twist jig 9A toward the stator 1. As a result, the stator 1 moves closer to the first twist jig 9A in the axial direction, as shown in Figures 5(B) and 7.

[0070] This operation displaces the coil end 7a of the protruding portion 7A in the axial and circumferential directions relative to the stator core 3. As a result, the protruding portion 7A is bent by twisting. In other words, the protruding portion 7A is bent as shown in the first and second layers in FIG. 1 .

[0071] At this time, the lower end of the first restraint wall 31 receives an upward force from the first stopper 39 in response to the approaching movement of the stator 1. In response to this upward force, the first coil spring 37 bends, causing the first restraint wall 31 to rise and move away from the first twist ring 13.

[0072] Therefore, regardless of the axial approach of the stator 1 to the first twist jig 9A, the first restraint wall 31 is positioned on the outer periphery of the group of protrusions 7A in the first layer being twisted. As a result, the twisting of the group of protrusions 7A is performed while the first guide portion 31a restrains the outer periphery of the group of protrusions 7A on the outermost periphery. This restraint prevents deformation of the protrusions 7A, such as bulging outward in the radial direction.

[0073] If there is an initial axial gap between the first restraint wall 31 and the first stopper 39 when the first twist jig 9A is attached to the stator 1, the first restraint wall 31 may come into contact with the first stopper 39 as the twisting process progresses. The initial gap between the first restraint wall 31 and the first stopper 39 is set within a range that suppresses deformation of the protrusion 7A that would otherwise cause it to bulge outward in the radial direction until the first restraint wall 31 comes into contact with the first stopper 39.

[0074] If the initial gap is large, there is a risk that the protrusion 7A will bulge radially outward and deform through the gap between the first restraint wall 31 and the first stopper 39 before the first restraint wall 31 abuts against the first stopper 39.

[0075] Therefore, the initial gap is defined at least in a state where the first restraint wall 31 reaches the bending position 7Aa (see Figure 1), preferably between the upper and lower bending positions 7Aa and 7Ab, more preferably, reaches the lower bending position 7Ab, and even more preferably, is eliminated as in the embodiment.

[0076] In addition, the group of protrusions 7A in the second layer may deform radially inward depending on the situation, so it is effective to add a separate restraining wall to the inside of the second twist ring 15 as described above.

[0077] When the twisting process is completed, the first twisting jig 9A is raised, and as a result, the first and second twist rings 13 and 15 of the first twisting jig 9A are pulled out from the bent coil ends 7a of the first and second layers.

[0078] Before the first twist jig 9A is pulled out, the first twist jig 9A is twisted back, causing the first twist ring 13 and the second twist ring 15 to rotate in opposite directions and return slightly.

[0079] By twisting back, the circumferential pressing force between the outer gripping portion 17 and the inner protruding portion 19 and the coil end 7a is eliminated or alleviated, so that the first twist ring 13 and the second twist ring 15 can be smoothly released from the coil end 7a of the twisted protruding portion 7A.

[0080] When the twisting of the protrusions 7A in the first and second layers is completed in this manner, the jig exchanging mechanism positions the next twist jig 9 on the stator 1. The next twist jig 9 has inner and outer twist rings, not shown, similar to the first twist jig 9A. The positioned next twist jig 9 bends the protrusions 7A in the third and fourth layers by twisting, as shown in FIG. 1, using the same procedure as the first twist jig 9A. This twist jig 9 may also have restraining walls on either or both of the inner and outer radial sides.

[0081] When the twisting of the protrusions 7A in the third and fourth layers is completed, the jig exchanging mechanism positions the second twisting jig 9B on the stator 1. The positioned second twisting jig 9B bends the protrusions 7A in the fifth and sixth layers by twisting them as shown in FIG. 1 in the same manner as the first twisting jig 9A.

[0082] In the case of the second twist jig 9B, the second restraint wall 59 is positioned radially inward of the group of protrusions 7A in the sixth layer being twisted. Therefore, the twisting of the group of protrusions 7A is performed while the radially inward side of the innermost group of protrusions 7A is restrained by the second restraint wall 59. This restraint prevents the protrusions 7A from bending between the bending positions 7Aa and bulging radially inward.

[0083] In addition, the group of protrusions 7A in the fifth layer may deform radially outward depending on the situation. For this reason, it is effective to add a fifth restraining wall to the outside of the third twist ring 41.

[0084] After the twisting process, the coil ends 7 a are joined adjacent to each other in the radial direction of the stator core 3 between the first and second layers, between the third and fourth layers, and between the fifth and sixth layers.

[0085] As described above, in this embodiment, the first restraint wall 31 (second restraint wall 59) is supported by the first twist ring 13 (fourth twist ring 43) so as to be axially movable. Therefore, simply by performing the twisting operation, the first restraint wall 31 (second restraint wall 59) can be positioned radially outward (or inward) of the protruding portion 7A, and the first restraint wall 31 (second restraint wall 59) can suppress deformation of the protruding portion 7A during the twisting process, such as bulging outward (or inward) in the radial direction. As a result, damage to the insulating layer of the protruding portion 7A, such as breakage, is also suppressed.

[0086] Furthermore, in this embodiment, the first restraint wall 31 (second restraint wall 59) is made to protrude in the axial direction from the outer gripping portion 17 (inner gripping portion 47), thereby making it possible to reduce or eliminate the initial axial gap between the first restraint wall 31 (second restraint wall 59) and the stator core 3 when performing twist processing.

[0087] As a result, the first restraint wall 31 (second restraint wall 59) can more reliably suppress deformation of the protrusion 7A that causes it to bulge radially outward during twisting processing, and damage such as breakage of the insulating layer of the protrusion 7A can also be suppressed.

[0088] Even in this case, when the first constraint wall 31 (second constraint wall 59) comes into contact with the stator core 3 as the twisting process progresses, it is pushed axially toward the first twist ring 13 (fourth twist ring 43). This makes it possible to avoid problems such as interference between the stator core 3 and the first constraint wall 31 (second constraint wall 59) that would hinder the twisting process.

[0089] In this embodiment, the first restraint wall 31 (second restraint wall 59) abuts against the stator core 3 in the axial direction during twisting, and the outer gripping portion 17 (inner gripping portion 47) moves axially and circumferentially relative to the first restraint wall 31 (second restraint wall 59) that abuts against the stator core 3 during twisting.

[0090] Therefore, in this embodiment, the first restraint wall 31 (second restraint wall 59) is abutted against the stator core 3, and the outer gripping portion 17 (inner gripping portion 47) is moved axially and circumferentially in a stable state to perform twisting processing.

[0091] The twisting jig 9 of this embodiment includes a first coil spring 37 (second coil spring 65) that axially biases the first restraint wall 31 (second restraint wall 59) to maintain a protruding state relative to the outer gripping portion 17 (inner gripping portion 47). This prevents the first restraint wall 31 (second restraint wall 59) from accidentally moving to retract, and more reliably prevents deformation of the protruding portion 7A that would otherwise bulge outward in the radial direction.

[0092] REFERENCE SIGNS LIST 1 Stator 3 Stator core 7 Segment coil 7A Protrusion 7Aa Bending position 7a Coil end 9A First twist jig 9B Second twist jig 13 First twist ring (twisting member) 15 Second twist ring (twisting member) 17 Outer gripping portion (gripping portion) 19 Inner gripping portion (gripping portion) 31 First restraining wall 37 First coil spring (biasing member) 41 Third twist ring (twisting member) 43 Fourth twist ring (twisting member) 45 Outer gripping portion (gripping portion) 47 Inner gripping portion (gripping portion) 59 Second restraining wall 65 Second coil spring (biasing member)

Claims

1. A stator twisting jig in which a protruding portion relative to a stator core, including a coil end of a segment coil held in the stator core, is bent circumferentially by twisting, comprising: a twisting member having a gripping portion that grips the coil end and displaces it relatively in the axial and circumferential directions with respect to the stator core to bend the protruding portion; and a restraining wall that is supported radially outside or inside the twisting member so as to be movable in the axial direction, and that restrains the protruding portion on the radial outside or inside when bent in a protruding state protruding in the axial direction relative to the gripping portion.

2. A twist processing jig according to claim 1, wherein the twist member has a circular shape, and the restraint wall has a circular shape located on the outer or inner side in the radial direction relative to the twist member.

3. A twist processing jig as claimed in claim 1, wherein the restraining wall abuts against the stator core in the axial direction during the twisting process, and the gripping portion moves in the axial direction relative to the restraining wall that abuts against the stator core during the twisting process.

4. A twist processing jig according to any one of claims 1 to 3, comprising an urging member that urges the restraint wall in the axial direction to maintain the protruding state relative to the gripping portion.

5. A twist processing jig according to any one of claims 1 to 3, wherein the twist member comprises an outer member and an inner member located on the outside and inside of the radial direction and rotating in opposite directions to each other to bend the protrusion in opposite circumferential directions on the outside and inside of the radial direction, and the restraint wall is located on the outside of the radial direction of the outer member of the twist member or on the inside of the radial direction of the inner member of the twist member.

6. A twisting device equipped with the twisting jig according to any one of claims 1 to 3.

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