Manufacturing method for stator coil and manufacturing apparatus for stator coil

Abstract

To solve the problem in which there was no coil manufacturing method capable of forming a low coil height inserted into a stator slot with a simple configuration.SOLUTION: The manufacturing method includes steps of inserting a coil conductor into a slot formed along the axial direction of a stator core, gripping an end portion of the coil conductor protruding from an end face of the stator core of the inserted coil conductor radially from the stator core by a gripping portion rotatably supported by a claw portion, and rotating the claw portion in the circumferential direction of the stator core while moving it axially toward the end face of the stator core, thereby bending the gripped coil conductor end toward the end face of the stator core.SELECTED DRAWING: Figure 7

Description

[Technical Field]

[0001] The present disclosure relates to a method and an apparatus for manufacturing a stator coil. [Background technology]

[0002] Rotating electric machines are installed in vehicles as a drive source for electric vehicles and the like, or to recover power through regenerative braking. Rotating electric machines consist of a stator and a rotor, and the stator has multiple teeth protruding axially from a cylindrical iron core. Coil material such as copper is wound around the multiple teeth, and the coil material wound around certain teeth is connected to form a circular coil.

[0003] In segment coils, which use rectangular wire as the coil material, the coil material is formed into a U or I shape in advance and inserted into the slots formed between the stator teeth, and then the coil material that protrudes in the opposite direction to the insertion direction of the stator core is bent circumferentially.Then, the joints of the coil ends and the coil material that will be joined in the adjacent slot, which has also been bent in the same way, are brought close to each other and joined.

[0004] The coil material is covered with an insulating coating to provide insulation between the stator core and the coil, and the insulating coating is removed beforehand at the joints at the ends of the coil material to allow for electrical connection. Tungsten Inert Gas (TIG) welding, laser welding, or other methods are used for joining. The joints between the coil materials are located at the highest point of axial protrusion from the axial end face of the stator core, so reducing the height of the coil joints from the stator core allows for the production of high-output yet compact rotating electric machines. A known segment coil processing method that reduces the height of the coil joints from the core end face involves a continuous bending process in which the coil ends are bent circumferentially and a pressing process in which they are pressed axially (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2019-187049 A (page 11, lines 9 to 40, Figures 7 to 9A) Summary of the Invention [Problem to be solved by the invention]

[0006] In the processing method described in Patent Document 1, the tip of the coil material is bent in the circumferential direction by rotating the bending jig while being pressed in the circumferential direction against one circumferential surface of the bending jig. Continuing to bend in the circumferential direction increases the bending radius at the base of the coil, so by pressing the coil in the axial direction while holding it in the radial direction with the opposite circumferential surface of the same jig, it is possible to form the coil with a smaller bending radius at the base of the coil and lower the height of the joint at the tip of the coil.

[0007] However, with this method, the bending jig does not follow the same trajectory as the bending trajectory of the tip of the coil material, but rather it is necessary to transition between the trajectory for the bending process and the trajectory for the pressing process during the bending process. This type of trajectory transition is difficult to achieve with a simple combination of mechanisms, and it is necessary to detect the position of the bending jig and accurately control the trajectory using a CNC (Computerized Numerical Control) device or similar, which means the processing equipment becomes large and cannot be manufactured inexpensively.

[0008] Furthermore, the coil is often not only bent in the circumferential and axial directions but also expanded in the radial direction. In this case, in addition to the configuration of Patent Document 1, a separate radial bending mechanism must be installed, which further increases the size of the equipment.

[0009] The present disclosure has been made to solve the above-mentioned problems, and provides a method for manufacturing a stator coil that can be formed with a low coil joint height using equipment with a simple configuration, and is highly reliable and inexpensive. [Means for solving the problem]

[0010] The method for manufacturing a stator coil disclosed herein involves inserting a coil conductor into a slot formed along the axial direction of the stator core, gripping the end of the inserted coil conductor protruding from the end face of the stator core from the radial direction of the stator core with a gripping portion rotatably supported by a claw portion, and rotating the claw portion circumferentially around the stator core while moving it axially toward the end face of the stator core, thereby bending the gripped coil conductor end toward the end face of the stator core as the gripping portion rotates. [Effects of the Invention]

[0011] According to the stator coil manufacturing method of the present disclosure, a stator with a low coil height can be manufactured reliably and inexpensively using equipment with a simple configuration. [Brief explanation of the drawings]

[0012] [Figure 1] 1 is a cross-sectional view of a rotating electric machine according to a first embodiment. [Figure 2] 1 is a perspective view showing the structure of a stator manufactured by the stator coil manufacturing method according to Embodiment 1. FIG. [Figure 3] 3A and 3B are diagrams showing a U-shaped coil material used in the method for manufacturing the stator coil according to the first embodiment. [Figure 4] 3A and 3B are diagrams showing an I-shaped coil material used in the method for manufacturing the stator coil according to the first embodiment. [Figure 5] 3 is a flowchart showing steps of a method for manufacturing a stator coil according to the first embodiment. FIG. [Figure 6] 1 is an external view of a stator coil manufacturing apparatus according to the first embodiment, showing a state before the coil material is bent and shaped. [Figure 7] FIG. 7 is a cross-sectional view of the stator coil manufacturing apparatus shown in FIG. 6. [Figure 8] 3 is an external view of the stator coil manufacturing apparatus according to the first embodiment, showing the state after the coil material has been bent and shaped. FIG. [Figure 9] FIG. 7 is a cross-sectional view of the stator coil manufacturing apparatus shown in FIG. 6. [Figure 10]2 is a perspective view showing the configuration of a coil clamp unit of the stator coil manufacturing apparatus according to the first embodiment. FIG. [Figure 11] 4A and 4B are diagrams showing a processed state of the coil material and a state of a gripping part of a coil clamp when the coil material is bent by the stator coil manufacturing apparatus according to the first embodiment. [Figure 12] 3A to 3C are diagrams illustrating the configuration of a driven bracket and a cylindrical cam of the stator coil manufacturing apparatus according to the first embodiment. [Figure 13] 3A to 3C are diagrams illustrating the configuration of a driven bracket and a cylindrical cam of the stator coil manufacturing apparatus according to the first embodiment. [Figure 14] 3A to 3C are diagrams illustrating an example of processing of a coil material by the stator coil manufacturing apparatus according to the first embodiment. [Figure 15] FIG. 10 is a cross-sectional view of a stator coil manufacturing apparatus according to a second embodiment. [Figure 16] FIG. 10 is a cross-sectional view of a stator coil manufacturing apparatus according to a second embodiment. [Figure 17] 10A and 10B are diagrams illustrating an example of processing of a coil material by the stator coil manufacturing apparatus according to the second embodiment. [Figure 18] 10 is a diagram showing the structure of a claw portion and a gripping portion of a stator coil manufacturing apparatus according to a third embodiment. FIG. [Figure 19] 10A and 10B are diagrams showing the structure of claws and grippers of a stator coil manufacturing device according to a third embodiment. [Figure 20] 10A and 10B are diagrams illustrating the shape of a groove formed at the tip of the coil material by a gripping unit of the stator coil manufacturing device according to the third embodiment. [Figure 21] 10 is a diagram illustrating a state in which coil materials that have been grooved by the stator coil manufacturing apparatus according to the third embodiment are joined together. FIG. [Figure 22] 10A and 10B are diagrams showing the structure of claws and grippers of a stator coil manufacturing device according to a third embodiment. [Figure 23] 10A and 10B are diagrams showing the structure of claws and grippers of a stator coil manufacturing device according to a third embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0013] Embodiment 1 <Configuration of rotating electric machine> FIG. 1 is a cross-sectional view of a rotating electric machine 20, showing the basic configuration of the rotating electric machine. The rotating electric machine 20 comprises a rotor 1 and a stator 2. A shaft 6 fixed to the center of the rotor 1 has the axis of rotation of the rotor 1 (indicated by the dashed-dotted line in FIG. 1, hereafter referred to as the shaft), and is held by a case 3 that constitutes the housing of the rotating electric machine 20 and a bearing 5 that is arranged on a bracket 4 above in the axial direction. The bearing 5 is positioned at the axial center of the case 3 and bracket 4, and the rotor 1 is held rotatably facing the stator 2. A plurality of permanent magnets are embedded inside the iron core that constitutes the rotor 1 at predetermined intervals around the circumference. Rotational torque is output to the outside by the shaft 6.

[0014] As shown in Figure 2, the stator 2 comprises an iron core 9, insulating members 11, and coils 10, as well as a frame 7 (see Figure 1) that holds them. The iron core 9 is made of electromagnetic steel sheets laminated in the axial direction. The electromagnetic steel sheets are composed of a yoke section that forms an annular ring on the outer periphery, and teeth sections that are narrower in the circumferential direction than the yoke section and protrude toward the rotor. The electromagnetic steel sheets laminated in the axial direction are integrated together by welding, crimping, or other methods. The iron core 9 may be an integrated iron core that is integrated in the circumferential direction, or it may be a split core in which multiple split laminated iron cores are combined circumferentially.

[0015] Coils 10 are wound around the teeth. Coils 10 are distributed winding coils in which rectangular wire segment coils are wound across the multiple teeth of the laminated core. The coil 10 uses a conductor wire (coil conductor) with an insulating coating. The conductor wire may be copper wire or aluminum wire. The coil 10 is insulated from the iron core 9 and other coils with different electrical phases by the insulating coating. Insulation is ensured between the coil 10 and the iron core 9 by inserting an insulating material such as paper or resin between them to prevent insulation breakdown between the coil 10 and the iron core 9 due to pinholes or the like that may occur in the insulating coating of the coil 10.

[0016] The core 9 and frame 7 are assembled by press fitting, shrink fitting, or other methods. The frame 7 is configured to be longer in the axial direction than the coil 10 and core 9, preventing the insulation of the coil 10 from being damaged due to scratches or other damage to the coating during assembly of the stator 2.

[0017] As shown in FIG. 1, one axial end of the frame 7 is configured with a flange 8 for fixing the frame 7 to the case 3. The flange 8 is fixed to the case 3 by screws or the like. The rotor 1 and stator 2 may be delivered assembled to the case 3 and bracket 4 as a finished rotating electric machine, or the rotor 1 and stator 2 may be delivered as components so that the customer can freely change the shapes of the case 3 and bracket 4 to suit the product specifications. When the stator 2 is delivered as a component, the stator 2 is fixed to the frame 7, and the flange 8 configured on one axial end of the frame 7 is attached to the customer's case 3 by screws or the like to form a finished rotating electric machine.

[0018] In the rotating electric machine 20, magnetic force is generated by supplying electric power from an external source to the coil 10 of the stator 2. By changing the phase of the electric power supplied to the coil 10 over time, attraction and repulsion occur continuously between the magnetic force generated in the stator 2 and the magnet embedded in the rotor 1. This causes the rotor 1 to rotate, transmitting rotational torque to the shaft 6 fixed to the rotor 1.

[0019] <Configuration of stator> The stator shown in Figure 2 is an example in which rectangular wire is used for the coil material, which is the coil conductor. Coil 10 is usually made up of multiple layers from the inside of iron core 9, and the coils in each layer are connected to the coils in other layers via bridge sections that span between the layers in the axial direction of iron core 9.

[0020] The iron core 9 and the coil material are insulated by an insulating material such as paper or resin. When bending the coil material in the circumferential direction of the iron core 9 (hereinafter referred to as the circumferential direction), the end of the iron core forms a bending radius, which may damage the insulating coating of the coil material that comes into contact with the end of the iron core. Therefore, by inserting a resin part of the insulating member 11 into the bending radius at the base of the coil, contact with the iron core 9 is prevented, protecting the insulating coating and ensuring an insulating distance.

[0021] The rectangular coil materials 10a and 10b are shaped as shown in Figure 3 or as shown in Figure 4. The insulating coating is removed from both ends of the coil material 10a to allow electrical connection with other coil materials. For the U-shaped coil material, a single coil material is pre-formed to form bridge sections 25 between different layers on the insertion side of the core 9, which is then inserted into the slots of the core 9. The coil material protruding from the axial end face of the core 9 is shaped circumferentially and axially to bring it close to adjacent coil materials, and the coil ends are joined to form the bridge sections between layers. For the I-shaped coil material 10b, the coil materials 26 and 27 protruding from the axial end face of the core 9 are shaped circumferentially and axially to bring it close to adjacent coil materials, and the coil ends are joined to form the bridge sections between layers. Furthermore, on the insertion side of the core 9, the ends of the coil materials shaped circumferentially and axially before insertion are joined to form the bridge sections between layers.

[0022] 5 is a flow diagram showing the steps of the method for manufacturing a stator coil according to embodiment 1. As described above, the insulating coating of the coil materials 10a, 10b is first stripped from the joints where they are joined to other coil materials, and then, for the U-shaped coil material 10a, a jumper section 25 between layers is formed on the insertion side of the coil material, and for the I-shaped coil material 10b, the coil material is shaped so that the insertion side of the coil material is close to the joints of other coils and a jumper section is formed by joining the coil ends.

[0023] In step S1, preformed coil materials 10a and 10b are inserted into the slots of the iron core 9 from one side of the iron core 9, and the inserted height in the axial direction is made equal to that of other adjacent coil materials.

[0024] In step S2, the coil material inserted into the slots of the core 9 is bent in the circumferential and axial directions so that the portion protruding axially from the core 9 is close to the joint of the end of the coil material. At this time, the bending direction of the coil material to be bent and the coil material to be joined are opposite to each other in the circumferential direction. At this time, depending on the final coil shape, a process of bending in the radial direction of the core 9 (hereinafter referred to as the radial direction) in addition to the bending in the circumferential and axial directions (step S2A in Figure 5) may be performed simultaneously or separately. In either case, the coil material is shaped in this process and the joint positions of the coil material ends are aligned.

[0025] In step S3, the joints between the coil materials 10a and 10b are joined using TIG welding or laser welding, etc., to electrically connect them. For the U-shaped coil material 10a, the protruding side from the iron core 9 is joined, and for the I-shaped coil material 10b, the coil ends protruding on both axial sides of the iron core are joined. Because the joint position of each coil material 10a and 10b is prone to variation due to springback and other factors, the coil ends are held together and joined while aligned. Joining is performed at all connections of the coil material at the transition sections between layers.

[0026] 6 and 8 are external views showing the stator coil manufacturing apparatus according to the first embodiment, with FIG. 7 being a cross-sectional view of FIG. 6 and FIG. 9 being a cross-sectional view of FIG. 8. FIG. 6 shows the state before, for example, the coil material 10a is bent and shaped in the above-mentioned step S2, and shows the state in which the coil clamp unit 40, which will be described later, grips the coating stripped portion at the end of the coil material 10a. FIG. 8 shows the external appearance of the stator coil manufacturing apparatus after the coil material is bent and shaped in step S2. The stator coil manufacturing apparatus is divided into a coil material shaping unit 30 and a fixing unit that fixes the stator 2 so that it does not move relative to the shaping unit. The fixing unit is omitted from this drawing because it fixes the core of the stator 2 using a general holding mechanism.

[0027] FIG. 10 is a perspective view showing the configuration of a coil clamping unit 40 that grips the coating-stripped portion at the tip of the coil material 10a attached to the coil material forming unit 30 in FIG. 6. The coil clamping unit 40 is composed of a chuck jaw end 41 that grips the joint where the insulating coating at the tip of the coil material has been stripped, drive-side chuck jaws 42 and fixed-side chuck jaws 43 that rotatably support the chuck jaw end 41, and a linear motion mechanism 45 and actuator 44 that drive the drive-side chuck jaws 42. As a result, the chuck jaw end 41, which serves as the gripping portion, is rotatable relative to the drive-side chuck jaws 42 and fixed-side chuck jaws 43, which serve as the jaw portions. The fixed-side chuck jaws 43 are attached to an L-shaped plate 46, which is fixed to a driven bracket 31 (described later) with screws or the like. As a result, the drive-side chuck jaws 42 and fixed-side chuck jaws 43 are axially arranged to face the ends of the coil materials 10a and 10b that protrude axially from the iron core 9.

[0028] With this configuration, as shown in Figures 6 and 7, the coating stripping portion at the tip of the coil material 10a is moved so as to be pinched from the radial direction of the coil material by the actuator 44 between the driving side chuck jaws 42 and the fixed side chuck jaws 43, and is gripped by the chuck jaw ends 41, and the entire coil clamp unit 40 is driven in the circumferential and axial directions relative to the stator 2, thereby shaping the coil material in the circumferential and axial directions.

[0029] FIG. 11 shows the processed state of the coil material and the states of the drive-side and fixed-side chuck jaws when the coil material is bent with the chuck jaw ends 41 rotatably supported by the drive-side chuck jaws 42 and the fixed-side chuck jaws 43. FIG. 11(a) shows a view from the circumferential direction of the stator 2, in which the coating stripped portion at the tip of the coil material 10a is gripped from the radial direction by the actuator 44 between the chuck jaw ends 41, which are gripping portions rotatably supported by the drive-side chuck jaws 42, which are claw portions, and the chuck jaw ends 41, which are gripping portions rotatably supported by the fixed-side chuck jaws 43, which are claw portions. FIG. 11(b) shows a view from the radial direction of FIG. 11(a). T0 to T3 in FIG. 11(c) show the progress of the forming of the coil material 10a in step S2. The arrows on the chuck jaw end 41 indicate the orientation of the chuck jaw end 41 relative to the drive-side chuck jaws 42 and the fixed-side chuck jaws 43. With this configuration, the gripping parts rotatably supported on the jaw parts grip the coil material so as to pinch it from the radial direction of the stator core, and while rotating the jaw parts in the circumferential direction of the stator core, they are moved in the axial direction toward the end face of the stator core, whereby the gripping parts rotate and bend the ends of the gripped coil material toward the end face of the stator core.

[0030] When the chuck jaw ends 41 are fixed to the drive side chuck jaws 42 and the fixed side chuck jaws 43 during circumferential and axial forming of the coil material, the coil material end gripped by the chuck jaw ends 41 from the axial direction remains facing the axial direction even when the coil clamp unit 40 is driven in the circumferential and axial directions, so the coil height cannot be reduced even when the coil material is completely formed.

[0031] In contrast, when the coil clamping unit 40 is driven in the circumferential and axial directions, as shown by the arrows in Figure 11(c), the chuck jaw ends 41 can rotate in the bending direction of the coil relative to the driving-side chuck jaws 42 and the fixed-side chuck jaws 43. As a result, when the forming of the coil material is completed, the coil ends are tilted in the circumferential direction, allowing the coil height to be reduced.

[0032] The coil clamp unit 40 fixes the number of coil materials to be formed on the circumference of the driven bracket 31 using L-shaped plates 46. When forming coils of different layers in the circumferential direction, the coil clamp unit 40 is moved radially so that it can grip the coil material of the layer to be processed.

[0033] The configurations of cylindrical cam 33 and driven bracket 31, which are the movable mechanism of coil clamp unit 40, are shown in Figures 12 and 13. Driven bracket 31 is movable in the axial direction along shaft 35, and is biased so as to press against cylindrical cam 33 by coil spring 32 (see Figures 6 and 7) attached to shaft 35. Driven bracket 31 is configured to move smoothly in the circumferential direction around shaft 35 in accordance with the shape of the cam (cam curve) by being pressed against cylindrical cam 33 via cam follower 34. Cylindrical cam 33 is fixed to iron core 9, and its position is fixed relative to stator 2, so that rotation of driven bracket 31 relative to cylindrical cam 33 causes driven bracket 31 to move in the axial direction of stator 2.

[0034] The driven bracket 31 is positioned in the rotational direction by a key 36 (see FIG. 7) driven into the middle of the axis of the shaft 35. Therefore, when the shaft 35 is rotated, the driven bracket rotates in the circumferential direction and is also driven axially in accordance with the cam curve of the cylindrical cam 33. FIG. 12 shows the state shown in FIGS. 6 and 7 in which the cam follower 34 is located above the cam curve and the driven bracket 31 is located axially higher, while FIG. 13 shows the state shown in FIGS. 8 and 9 in which the cam follower 34 is located below the cam curve and the driven bracket 31 is located axially lower. In FIG. 9, the key 36 also rotates when the shaft 35 rotates, so in FIG. 9 the key 36 is located on the front side of the shaft 35 and is not visible. The same applies to FIG. 16, which will be described later.

[0035] Instead of using the key 36 to position the shaft 35 and the driven bracket 31 in the rotational direction, a linear motion part such as a ball spline may be used. Also, a servo motor or the like is used to rotate the shaft 35, but this is not limiting and any actuator that can control the rotation angle may be used.

[0036] The coil material can be formed into a desired shape by configuring the cam curve of the cylindrical cam 33 to be the same as the trajectory that bends the joint at the tip of the coil material. In addition, by using the cylindrical cam 33, the coil material can be formed simultaneously in the circumferential and axial directions.

[0037] Furthermore, by making the cam curve of cylindrical cam 33 circumferentially symmetrical, one cylindrical cam can be used to form the coil material in both a clockwise and counterclockwise direction. When processing adjacent layers of coil material, the forming directions of the coil material on the inside and outside are opposite in the circumferential direction, so for example, after forming the coil material in the counterclockwise direction by rotating the outer driven bracket 31 counterclockwise, the coil clamp unit 40 can be moved one layer inward and the driven bracket 31 can be rotated clockwise, making it easy to form the coil material in the clockwise direction.

[0038] In the first embodiment, a cylindrical cam 33 is used as shown in Figures 12 and 13, but a grooved cam or other mechanism may also be used. That is, if a grooved cam is used instead of using the coil spring 32 to bias the driven bracket 31 into contact with the cylindrical cam 33, the cam follower can be pressed in the axial direction from the upper side of the grooved cam, so that the biasing spring can be eliminated and a simpler configuration can be achieved.

[0039] Coil processing is performed sequentially from the outer periphery to the inner periphery, or from the inner periphery to the outer periphery. Coils other than those in the layer to be processed are retracted in the insertion direction of the iron core 9 to prevent interference with the processing jig. Coils in a layer for which bending processing has been completed cannot be retracted in the axial direction due to the bending R at the base caused by forming the coil material. When the coils have a structure in which the coil layers are closely packed together, as in the stator shown in Figure 2, there is no gap between the coils, so the chuck jaw tips 41, drive-side chuck jaws 42, and fixed-side chuck jaws 43 may not be able to be inserted between the processed coil and the coil to be processed.

[0040] In this case, the chuck jaw ends 41, drive-side chuck jaws 42, and fixed-side chuck jaws 43 that grip the coil to be processed are positioned at a height that does not interfere with the processed coil, as shown in Fig. 14(a). At this time, the coil has already been bent at its base, so the bend R does not increase even if the coil is pressed in the axial direction.

[0041] 14(b) and (c), the processed target coil is pressed axially to form it close to the coil to be joined. The axial pressing can be performed by adding a pressing part to the forming equipment, or by using a positioning mechanism to position the coils relative to each other in the joining equipment, which is the next process.

[0042] As described above, by processing the coil material using the stator coil manufacturing device, the height of the coil material from the iron core 9 can be reduced. Simultaneous processing of circumferential bending and axial bending of the coil material can be achieved with a simple equipment configuration, so the coil material can be formed inexpensively.

[0043] Embodiment 2 15 and 16 are cross-sectional views of a stator coil manufacturing device according to embodiment 2. FIG. 15 shows the state before the coil is formed, and FIG. 16 shows the state after it has been formed. In addition to the forming described in embodiment 1, embodiment 2 adds a function to form the coil material in the radial direction of the iron core 9. The coating stripped portion of the coil material 10a is gripped by the rotatable chuck claw ends 41 of the coil clamp unit 40, and the coil material is formed in the circumferential and axial directions, just as described in embodiment 1.

[0044] In the first embodiment, coil clamp unit 40 is fixed to driven bracket 31 by L-shaped plate 46, but in the second embodiment, coil clamp unit 40 is configured to be movable in the radial direction of driven bracket 31. That is, a truncated cone-shaped lifter 51 is disposed between driven bracket 31 and coil spring 32, with shaft 54 ​​passing through it. Coil spring 32 is attached to lifter 51, and lifter 51 is disposed so that the surface of the minor diameter of the truncated cone faces the surface of driven bracket 31.

[0045] One end of the L-shaped plate 52 is provided with a tapered portion 53 that comes into contact with the lifter 51, and the fixed chuck jaws 43 are fixed to the other end of the L-shaped plate 52. A shoulder screw 55 is used that fits into an elongated hole drilled in the L-shaped plate 52 in the elongated hole direction, and the L-shaped plate 52 is held in the axial direction with the screw head, allowing the coil clamp unit 40 to move radially on the driven bracket 31. While Fig. 13 shows an example using an elongated hole and a shoulder screw, a configuration that uses a linear motion component such as an LM guide (Linear Motion Guide) is also acceptable.

[0046] The tapered portion 53 of the L-shaped plate 52 is configured to be in close contact with the lifter 51 by the biasing force of the coil spring 32 or the like. In FIG. 15 , a portion of the side surface of the minor axis of the truncated cone shape of the lifter 51 is in close contact with the lifter 51, and a lowering space for the lifter 51 is formed between the minor axis of the truncated cone shape of the lifter 51 and the upper surface of the driven bracket 31. Note that the multiple axial lines drawn in the lowering space in FIG. 15 show the arrangement of the tapered portion 53 arranged circumferentially on the far side of the page of the shaft 54. During coil forming, as shown in FIG. 16 , as the lifter 51 descends in the axial direction, the tapered portion 53 comes into close contact with the minor axis side of the truncated cone shape of the lifter 51 from the major axis side, and presses against the tapered portion 53, causing the L-shaped plate 52 to move radially along the elongated hole. This causes the coil clamp portion 40 to expand radially around the iron core 9, allowing the coil material 10a to be formed radially as well. At this time, if the shaft 54 ​​does not descend in the axial direction, the coil spring 32 will expand and the radial biasing force of the tapered portion 53 will weaken, so the shaft 54 ​​will also descend by the amount that the lifter 51 descends. The lifter 51 descends only up to the top surface of the key 36. Furthermore, the coil spring 32 biases the driven bracket 31 axially downward, so that the driven bracket 31 is biased so as to be pressed against the cylindrical cam 33, as in the first embodiment. In this way, by using the coil clamp unit 40 having the lifter 51 and the L-shaped plate 52 on which the tapered portion 53 is formed, the coil material 10a can be formed in the radial direction as well as the circumferential and axial directions at the same time.

[0047] In the example of Figure 15, a shoulder screw 55 is used that fits into an elongated hole drilled in the L-shaped plate 52 in the elongated hole direction. The head of the screw holds the L-shaped plate 52 in the axial direction, allowing radial movement of the coil clamp part 40. Figure 13 shows an example using an elongated hole and a shoulder screw, but other configurations that use linear motion parts such as an LM guide (Linear Motion Guide) are also acceptable.

[0048] The actuator that drives the shaft in the rotational and axial directions may be a combination of a servo motor and a cylinder, but is not limited to this. The mechanism that moves in the rotational and axial directions is a common structure and will not be described here.

[0049] In the second embodiment, the chuck section consisting of the chuck jaw tips 41, the drive-side chuck jaws 42, and the fixed-side chuck jaws 43 is configured to be movable in the radial direction, so that the coil can be formed in a position that is open in the circumferential direction. In cases where there is no gap between the coils and the chuck jaw tips 41, the drive-side chuck jaws 42, and the fixed-side chuck jaws 43 cannot be inserted between the processed coil and the coil to be processed, a radial gap can be created between the processed coil and the coil to be processed as shown in Fig. 17(a), so that the chuck jaw tips 41, the drive-side chuck jaws 42, and the fixed-side chuck jaws 43 can be inserted between the coil layers.

[0050] After forming the coil material, the coil is expanded in the circumferential direction and pressed radially to bring the joints into close proximity, as shown in Figure 17(b). The radial pressing can be performed by adding a pressing part to the coil forming equipment, or it can be performed by the positioning mechanism on the coil joining equipment side in step S3, which also positions the coils relative to each other.

[0051] As a result, the forming equipment is inexpensive and the processing costs are low. At the same time, the height of the coil material from the iron core can be reduced. Simultaneous processing can be achieved with a simple equipment configuration, so the forming of coil material can be achieved inexpensively.

[0052] Embodiment 3 An example of the structure of the claws and gripping portion of a stator coil manufacturing apparatus according to the third embodiment is shown in Figures 18 and 19. A mountain-shaped groove is formed in the chuck claw tips 41 that grip the coil material, and Figure 18 shows the angle of the groove when gripping the end of the coil material, while Figure 19 shows the angle of the groove when the chuck claw tips 41 have rotated after the circumferential bending of the coil material end is completed. Because the coil material is made of a relatively soft metal such as copper, the grooves formed in the chuck claw tips 41 when gripping the peeled portion of the insulating coating on the end of the coil material form a groove shape at the joint where the coil material is joined together. The groove shape is formed by the pressure of the actuator that drives the chuck claw tips 41.

[0053] An example of the groove shape formed by the chuck jaws 41 on the end of the coil material is shown in Figure 20. The groove is formed on one side of the end of the coil material by a groove formed on the chuck jaws 41 supported by the drive-side chuck jaws 42. However, a similar groove may also be formed on the chuck jaws 41 supported by the fixed-side chuck jaws 43, so that grooves are formed on one or both sides of the end of the coil material. The groove shape is not limited to the triangular groove shown in this figure; it can be any concave-convex shape such as a chevron groove, a square groove, or a semicircular groove. Any shape that allows the concave and convex portions to catch can be used, and the number of grooves can also be selected arbitrarily. The coil material is positioned relative to adjacent coil material by machining in the circumferential and axial directions, and then joined by TIG welding, laser welding, or the like.

[0054] The positioning of the coil material is subject to constraints on the equipment configuration due to the coil arrangement of the stator or the space required for the joining device. Furthermore, if equipment constraints prevent the gripping force on the end of the coil material from being strong enough, the position of the coil joining part is likely to shift. By forming grooves on the ends of the coil material to be joined, the grooves formed on the coil ends interlock with each other when the coil materials are positioned as shown in Figure 21. This makes it possible to position the coil ends with a weak grip in the radial direction, allowing the positioning mechanism to be made smaller.

[0055] When forming a groove in the end of the coil material, the angle of the groove needs to be adjusted so that the groove will mesh with the other coils that will be joined at the end of bending the coil material. Therefore, the angle of the groove in Figure 18 provided on the chuck jaw end 41 that forms the groove in the end of the coil material at the start of forming the coil material needs to be constant.

[0056] 22 shows an example of a structure for keeping the angle of the chuck jaw end 41 constant at the start of forming the coil material. As shown in the figure, spring hooks are provided on both the side of the chuck jaw end 41 that does not grip the end of the coil material and the drive-side chuck jaw 42 that supports the chuck jaw end 41, and a torsion spring 63 urges the chuck jaw end 41 in a counterclockwise direction. A stopper that engages with the spring hook provided on the chuck jaw end 41 is provided on the lower left of the drive-side chuck jaw 42. The engagement of the chuck jaw end 41 with this stopper keeps the angle of the groove formed in the chuck jaw end 41 constant when gripping. As shown in Figure 23, when bending the end of the coil material in the circumferential direction, the chuck jaws 41 rotate in the direction B, causing the stopper and the chuck jaws 41 to disengage. Thereafter, the chuck jaws 41 rotate against the biasing force of the torsion spring until the groove angle of the chuck jaws 41 is in the same vertical direction as the axial direction. When the bending process is completed and the chuck jaws 41 release their grip on the end of the coil material, the biasing force of the torsion spring 43 returns the chuck jaws 41 to the position of the stopper shown in Figure 22 and engages with the stopper. By allowing the chuck jaws 41 to follow the bending angle of the coil material, the groove angle at the end of forming the coil material can be oriented in a direction that allows the grooves to interlock with each other.

[0057] As a method for keeping the posture of the chuck jaw end 41 constant when gripping the coil material, an example of biasing in one direction with a torsion spring has been shown, but this is not limited to this as long as the gripping position of the chuck jaw end can be kept constant and the chuck jaw end can follow the shaping of the coil material.

[0058] By providing the above-described configuration, the positioning device for joining the coil materials can be easily configured, so that welding equipment can be procured at low cost, and joining of the coil materials can be realized at low cost.

[0059] Although the present disclosure describes various exemplary embodiments and examples, the various features, aspects, and functions described in one or more embodiments are not limited to application to a particular embodiment, but may be applied to the embodiments alone or in various combinations. Therefore, countless variations not exemplified are conceivable within the scope of the technology disclosed in this specification, including, for example, cases where at least one component is modified, added, or omitted, and cases where at least one component is extracted and combined with components of another embodiment.

[0060] Various aspects of the present disclosure are summarized below as appendices.

[0061] (Appendix 1) A method for manufacturing a stator coil, comprising the steps of: inserting a coil conductor into a slot formed along the axial direction of a stator core; gripping an end of the inserted coil conductor protruding from an end face of the stator core from the radial direction of the stator core with a gripping portion rotatably supported by a claw portion; rotating the claw portion circumferentially of the stator core while moving it axially toward the end face of the stator core, thereby bending the gripped coil conductor end toward the stator end face while the gripping portion rotates. (Appendix 2) The method for manufacturing a stator coil described in Appendix 1, characterized in that the claw portions are arranged on a driven bracket that is movable along a shaft extending in the axial direction, and the driven bracket moves along a cam curve formed on a cylindrical cam fixed to the stator core, thereby causing the claw portions to move in the circumferential direction and the axial direction. (Appendix 3) The method for manufacturing a stator coil described in Appendix 2, wherein the driven bracket is biased so as to press against the cylindrical cam by a coil spring attached to the shaft. (Appendix 4) The method for manufacturing a stator coil described in any one of appendixes 1 to 3, characterized in that the claw portions also move in the radial direction, and the ends of the coil conductor are bent so as to extend radially wider than the diameter of the stator core. (Appendix 5) The method for manufacturing a stator coil according to Appendix 3, characterized in that a lifter having a truncated cone shape with a long diameter bottom surface facing the coil spring and a short diameter end surface facing the driven bracket is disposed around the shaft between the coil spring and the driven bracket, the claw portions are attached to a plate having a tapered portion that is in contact with a side surface of the lifter and is movable in the radial direction on the driven bracket in response to axial movement of the lifter, and the claw portions move in the radial direction as the lifter moves in the axial direction. (Appendix 6) The method for manufacturing a stator coil according to any one of Supplementary Notes 1 to 5, wherein a groove is formed in the gripping portion. (Appendix 7) The method for manufacturing a stator coil according to Appendix 6 is characterized in that it includes a stopper that engages with the gripping portion biased by an elastic material so that multiple grooves formed in the gripping portion are held at a predetermined angle before gripping the coil conductor end. (Appendix 8) A method for manufacturing a stator coil, comprising: inserting a first coil conductor into a slot formed along the axial direction of a stator core; gripping an end of the inserted first coil conductor protruding from an end face of the stator core from the radial direction of the stator core with a gripping portion rotatably supported by a claw portion; rotating the claw portion in one direction around the stator core while moving it in the axial direction toward the end face of the stator core, thereby bending the gripped end of the first coil conductor toward the end face of the stator core; then gripping an end of a second coil conductor inserted into an adjacent slot with the gripping portion; rotating the claw portion in the direction opposite to the one direction around the circumferential direction, thereby bending the end of the second coil conductor in the direction opposite to the end of the first coil conductor; and joining the bent end of the first coil conductor to the end of the second coil conductor. (Appendix 9) The method for manufacturing a stator coil described in Appendix 8 is characterized in that the claw portions are arranged on a driven bracket that is movable along a shaft extending in the axial direction, the driven bracket moves in the circumferential and axial directions of the stator core along a cam curve of a cylindrical cam fixed to the stator core, and the cam curve is made circumferentially symmetrical, so that the cylindrical cam is used both for clockwise shaping of the first coil conductor and counterclockwise shaping of the second coil conductor. (Appendix 10) a cylindrical cam that guides the movement of the driven bracket; claws attached to plates that extend radially outward from the driven bracket to the stator core; and grippers rotatably supported on the claws, wherein ends of coil conductors that are inserted into slots formed along the axial direction of the stator core and that protrude from an end face of the stator core are gripped by the grippers in the radial direction of the stator core, and the grippers rotate as the claws move around the stator core in both the axial and circumferential directions of the stator core due to movement of the driven bracket, thereby bending the gripped coil conductor ends toward the end face of the stator core. (Appendix 11) 11. The stator coil manufacturing device according to claim 10, further comprising: a coil spring attached to the shaft and biasing the driven bracket so as to press it against the cylindrical cam; a lifter arranged around the shaft and having a truncated cone shape with a longer diameter bottom surface facing the coil spring and a shorter diameter end surface facing the driven bracket; and a tapered portion formed on the plate that is in contact with a side surface of the lifter and is movable in the radial direction of the stator core in response to movement of the lifter in the axial direction, wherein the claw portions are moved in the radial direction by the lifter that moves in response to movement of the shaft in the axial direction. (Appendix 12) 12. The stator coil manufacturing apparatus according to claim 10, wherein a groove is formed in the gripping portion. (Appendix 13) 13. The stator coil manufacturing apparatus according to claim 12, further comprising a stopper attached to the claw portion and engaging with the gripping portion biased by an elastic material so as to hold the gripping portion at a predetermined angle to the claw portion. [Explanation of symbols]

[0062] 1: rotor, 2: stator, 3: case, 4: bracket, 5: bearing, 6: shaft, 7: frame, 8: flange portion, 9: iron core, 10: coil, 10a, 10b: coil material, 11: insulating member, 20: rotating electric machine, 25: transition portion, 26, 27: coil material, 30: coil material forming portion, 31: driven bracket, 32: coil spring, 33: cylindrical cam, 34: cam follower, 35: shaft, 36: key, 40: coil clamp portion, 41: chuck jaw end, 42: drive side chuck jaw, 43: fixed side chuck jaw, 44: actuator, 45: linear motion mechanism, 46: L-shaped plate, 51: lifter, 52: L-shaped plate, 53: tapered portion, 54: shaft, 55: stepped screw, 63: torsion spring.

Claims

1. A method for manufacturing a stator coil, comprising the steps of: inserting a coil conductor into a slot formed along the axial direction of a stator core; gripping an end of the inserted coil conductor protruding from an end face of the stator core from the radial direction of the stator core with a gripping portion rotatably supported by a claw portion; rotating the claw portion circumferentially of the stator core while moving it axially toward the end face of the stator core, thereby bending the gripped coil conductor end toward the end face of the stator core as the gripping portion rotates.

2. 2. The method for manufacturing a stator coil according to claim 1, characterized in that the claw portions are arranged on a driven bracket that is movable along a shaft extending in the axial direction, and the driven bracket moves along a cam curve formed on a cylindrical cam fixed to the stator core, thereby causing the claw portions to move in the circumferential direction and the axial direction.

3. 3. The method for manufacturing a stator coil according to claim 2, wherein the driven bracket is biased so as to press against the cylindrical cam by a coil spring attached to the shaft.

4. 4. The method for manufacturing a stator coil according to claim 1, wherein the claw portions also move in the radial direction, and the ends of the coil conductors are bent so as to be wider in the radial direction than the diameter of the stator core.

5. 4. The method for manufacturing a stator coil according to claim 3, wherein a lifter having a truncated cone shape with a long diameter bottom surface facing the coil spring and a short diameter end surface facing the driven bracket is arranged around the shaft between the coil spring and the driven bracket, the claw portions are attached to a plate having a tapered portion that is in contact with a side surface of the lifter and can move in the radial direction on the driven bracket in response to axial movement of the lifter, and the claw portions move in the radial direction as the lifter moves in the axial direction.

6. 2. The method for manufacturing a stator coil according to claim 1, wherein a groove is formed in the gripping portion.

7. 7. The method for manufacturing a stator coil according to claim 6, further comprising a stopper that engages with the gripping portion, which is biased by an elastic material, so that a plurality of grooves formed in the gripping portion are held at a predetermined angle before gripping the coil conductor end.

8. A method for manufacturing a stator coil, comprising: inserting a first coil conductor into a slot formed along the axial direction of a stator core; gripping an end of the inserted first coil conductor protruding from an end face of the stator core from a radial direction of the stator core with a gripping portion rotatably supported on a claw portion; rotating the claw portion in one direction around the stator core while moving it in the axial direction toward the end face of the stator core, thereby bending the gripped end of the first coil conductor toward the end face of the stator core; then gripping an end of a second coil conductor inserted into an adjacent slot with the gripping portion; rotating the claw portion in a direction opposite to the one direction around the circumferential direction, thereby bending the end of the second coil conductor in the opposite direction to the end of the first coil conductor; and joining the bent end of the first coil conductor to the end of the second coil conductor.

9. The method for manufacturing a stator coil according to claim 8, characterized in that the claw portions are arranged on a driven bracket that is movable along a shaft extending in the axial direction, the driven bracket moves in the circumferential and axial directions of the stator core along a cam curve of a cylindrical cam fixed to the stator core, and by making the cam curve circumferentially symmetrical, the cylindrical cam is used to both shape the first coil conductor clockwise and the second coil conductor counterclockwise.

10. a cylindrical cam that guides the movement of the driven bracket; claws attached to plates that extend radially outward from the driven bracket to the stator core; and grippers rotatably supported on the claws, wherein ends of coil conductors that are inserted into slots formed along the axial direction of the stator core and that protrude from an end face of the stator core are gripped by the grippers in the radial direction of the stator core, and the grippers rotate as the claws move around the stator core in both the axial and circumferential directions of the stator core due to movement of the driven bracket, thereby bending the gripped coil conductor ends toward the end face of the stator core.

11. 11. The stator coil manufacturing device according to claim 10, further comprising: a coil spring attached to the shaft and biasing the driven bracket so as to press it against the cylindrical cam; a lifter arranged around the shaft and having a truncated cone shape with a longer diameter bottom surface facing the coil spring and a shorter diameter end surface facing the driven bracket; and a tapered portion formed on the plate that contacts a side surface of the lifter and is movable in the radial direction of the stator core in response to the axial movement of the lifter, wherein the claw portions move in the radial direction due to the lifter moving in response to the axial movement of the shaft.

12. 12. The stator coil manufacturing device according to claim 10, wherein a groove is formed in the gripping portion.

13. 13. The stator coil manufacturing apparatus according to claim 12, further comprising a stopper attached to the claw portion and engaging with the gripping portion biased by an elastic material so as to hold the gripping portion at a predetermined angle to the claw portion.

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