Method for manufacturing stator of rotary electric machine, and method for manufacturing rotary electric machine

Abstract

A method for manufacturing a stator of a rotary electric machine, the stator comprising an annular stator core in which a slot is formed, and a coil of rectangular cross section that penetrates the slot, the coil having a coil end part protruding axially outward from the stator core, and a welding connection part joined to another coil. A plurality of the slots are formed along the circumferential direction of the stator core. The plurality of coils are inserted along the radial direction of the slots. The coil end part includes a first coil end part that is the coil end part of a first coil among the coils, and a second coil end part that is the coil end part of a second coil adjacent to the first coil. The first coil end part and the second coil end part are provided with facing surfaces that face each other, and end surfaces that are the surface of the tip protruding axially outward. By inclining the second coil end part with respect to the first coil end part, the facing surface of the first coil end part and the end surface of the second coil end part are brought into contact with each other. The welding connection part is formed by directing a laser from a torch over a range defined by the contact between the facing surface of the first coil end part and the end surface of the second coil end part. the laser having an inclination angle α with reference to the facing surface of the first coil end part. In the process of forming the welding connection part, the torch is driven in the radial direction and / or the circumferential direction.

Description

Method for manufacturing a stator of a rotating electrical machine, method for manufacturing a rotating electrical machine

[0001] The present invention relates to a method for manufacturing a stator of a rotating electrical machine and a method for manufacturing a rotating electrical machine.

[0002] In a drive motor, when joining coil ends of coils inserted into a stator, since the number of coil ends to be welded is large, shortening of the total welding time is required. As an example of coil end welding, Patent Document 1 below discloses a laser welding technique for welding a fillet portion F at a defined constant angle α.

[0003] Japanese Patent Application Laid-Open No. 2019-115188

[0004] During coil end welding, there are variations in the length of the coils and variations in the height of the coil ends. Therefore, when welding with a laser, steps or gaps occur on the irradiation surface. In addition, the heat input by the laser becomes non-uniform in each welded portion, resulting in a problem that the quality of the welding becomes unstable. Therefore, in view of the technique described in Patent Document 1, an object of the present invention is to provide a method for manufacturing a stator of a rotating electrical machine and a method for manufacturing a rotating electrical machine that achieve stabilization of welding quality and shortening of welding time.

[0005] A stator for a rotating electric machine and a method for manufacturing a rotating electric machine, comprising: an annular stator core with slots formed therein; and coils penetrating the slots and having a rectangular cross-section, wherein each coil has a coil end portion projecting axially outward from the stator core and a welded connection portion joined to other coils, wherein a plurality of slots are formed along the circumferential direction of the stator core, the plurality of coils are inserted along the radial direction of the slots, and the coil end portion includes a first coil end portion which is the coil end portion of a first coil, and a second coil end portion which is the coil end portion of a second coil adjacent to the first coil, and the first coil end The end portion and the second coil end portion each have opposing surfaces which are surfaces facing each other and an end surface which is a tip surface projecting outward in the axial direction. The second coil end portion is tilted relative to the first coil end portion so that the opposing surface of the first coil end portion and the end surface of the second coil end portion come into contact. The welding joint is formed by irradiating a laser with an inclination angle α relative to the opposing surface of the first coil end portion from the torch over the area defined by the contact between the opposing surface of the first coil end portion and the end surface of the second coil end portion, and during the process of forming the welding joint, the torch is driven in at least one direction of the radial and circumferential directions.

[0006] This invention provides a method for manufacturing a stator for a rotating electric machine and a method for manufacturing a rotating electric machine, which can stabilize welding quality and shorten welding time.

[0007] A cross-sectional view illustrating the configuration of a rotating electric machine. A diagram illustrating the coil inserted into the stator core and the contact state between coils according to the manufacturing method of the present invention. A diagram illustrating the welding joint between coil ends according to the manufacturing method of the present invention. A diagram illustrating the process from contact between coil ends to welding joint according to the manufacturing method of the present invention. First modified example, second modified example.

[0008] Embodiments of the present invention will be described below with reference to the drawings. The following description and drawings are illustrative for illustrating the present invention, and have been omitted and simplified as appropriate for clarity of explanation. The present invention can also be carried out in various other forms. Unless otherwise specified, each component may be singular or plural.

[0009] The positions, sizes, shapes, and ranges of the components shown in the drawings may not represent their actual positions, sizes, shapes, and ranges in order to facilitate understanding of the invention. Therefore, the present invention is not necessarily limited to the positions, sizes, shapes, and ranges disclosed in the drawings.

[0010] (Overall Configuration and Manufacturing Method) (Figures 1 and 2) Figure 2(a) is a cross-sectional view illustrating multiple coils inserted into slots, and Figure 2(b) is a diagram illustrating the contact state of the coil ends before welding. The rotating electric machine 100 comprises a stator 1 and a rotor 2. The stator 1 has an annular stator core 1a with multiple slots 4 formed along the circumferential direction. Multiple coils 3, each with a rectangular cross-section, are inserted through the slots 4. The cross-section of the coils 3 may be substantially rectangular. The coils 3 have coil end portions that protrude axially outward from the stator core 1a. The coils 3 are connected to each other by forming a welded connection portion, described later, at the point where each coil end portion contacts each other.

[0011] Of the coils 3, the first coil 6 and the second coil 7 are inserted alternately in the radial direction within the slot 4. The first coil end portion 6a of the first coil 6 and the second coil end portion 7a of the second coil 7 are each covered at least partially with the insulating coating 5. In other words, at least a portion of the conductive parts of the first coil 6 and the second coil 7 is exposed from the insulating coating 5. The portions of the first coil end portion 6a and the second coil end portion 7a that are covered with the insulating coating 5 are the portions that are inserted into the slot 4 of the stator core 1a.

[0012] In the process of welding the first coil end portion 6a and the second coil end portion 7a together, it is necessary to ensure that the heights of the first coil end portion 6a and the second coil end portion 7a from the stator core 1a are different. For example, as shown in Figure 2, the height of the first coil end portion 6a from the stator core 1a is higher than the height of the second coil end portion 7a from the stator core 1a. In this way, the coil winding on the fixed core 1a is completed in advance so that the heights of the coil end portions to be welded are a combination of a high side and a low side. The first coil end portion 6a is fixed, and the second coil end portion 7a is tilted relative to the first coil end portion 6a so that they come into contact with each other.

[0013] (Figure 3) The first coil end portion 6a and the second coil end portion 7a each have opposing surfaces 6b and 7b that face each other, and end surfaces 6c and 7c that are the tip surfaces that protrude outward in the axial direction from the stator core 1a. Of the conductors of the first coil 6 and the second coil 7, a portion of the opposing surfaces 6b and 7b and the end surfaces 6c and 7c are exposed from the insulating coating 5 (Figure 2) described above.

[0014] The second coil end portion 7a is positioned relative to the first coil end portion 6a of the central axis 16 parallel to the axial direction of the stator 1. The second coil end portion 7a is positioned such that the central axis 17 of the second coil end portion 7a is inclined by an angle β, thereby bringing the opposing surface 6b of the first coil end portion 6a and the end surface 7c of the second coil end portion 7a into contact.

[0015] The area to be welded is defined by the contact between the opposing surface 6b of the first coil end portion 6a and the end surface 7c of the second coil end portion 7a. A laser with an inclination angle α relative to the opposing surface 6b of the first coil end portion 6a is irradiated from the welding torch 9a to this defined area. As a result, a welded connection portion 10 is formed at the contact point between the opposing surface 6b of the first coil end portion 6a and the end surface 7c of the second coil end portion 7a, thereby joining the coil ends together.

[0016] During the formation process of the welded joint 10, the inclination angle α of the laser irradiated from the welding torch 9a is kept constant. This allows for continuous welding to multiple coil ends by driving the stator core 1a in at least one direction, radially or circumferentially, during the formation process of the welded joint 10. Specifically, the welding operation is repeated by rotating the stator core 1a one full turn in the circumferential direction, forming the welded joint 10 with the welding torch 9a, then moving the welding torch 9a radially, and forming the welded joint 10 for another full turn in the circumferential direction.

[0017] This allows the formation of the welded joint 10 to be completed at all coil ends inserted into the stator core 1a without changing the laser inclination angle α. Furthermore, since the time required to move the welding torch 9a one by one is eliminated compared to conventional methods, the welding time can be shortened. In addition, checking the conditions of the welding area at the start of welding becomes easier, making it easier for the scanner to recognize the welding area environment.

[0018] Alternatively, the welding torch 9a may be driven axially while keeping the laser tilt angle α constant, and the laser may be irradiated toward the welding connection portion 10 of the second coil end portion 7a. The contact portions between the first coil end portion 6a and the second coil end portion 7a are not all at a constant height from the stator core 1a, but there is a predetermined variation in height. Therefore, by driving the welding torch 9a axially to form the welding connection portion 10, the welding connection portion 10 can be formed in a way that accommodates such variations in the height of the contact portions between the coils.

[0019] As mentioned above, the first coil end portion 6a and the second coil end portion 7a must be different, but on the opposing surface 6b of the first coil end portion 6a, when L1 is the shortest distance from the stator core 1a to the position furthest from the stator core 1a, and L2 is the shortest distance from the stator core 1a to the welded connection portion 10, the relationship L1 > L2 holds. This ensures that when the second coil end portion 7a is tilted toward the first coil end portion 6a, it can reliably make contact with the opposing surface 6b of the first coil end portion 6a.

[0020] Furthermore, in the coil manufacturing stage before insertion into the stator core 1a, burrs and sags are formed on the end face 7c (6c) when the coil is sheared. When bringing the second coil end portion 7a into contact with the opposing surface 6b of the first coil end portion 6a in this state, the side of the end face 7c that has formed the sag is brought into contact with the opposing surface 6b. By doing so, the contact area is stabilized, and thus the welding quality is stabilized.

[0021] (Figure 4) The welding connection process of the two coil ends will be explained using the diagrams in Figures 4(a) to 4(c). As shown in Figure 4(a), the first coil end portion 6a is inserted into the stator core 1a (Figure 3) such that the height at which it protrudes outward from the stator core 1a is greater than the height of the second coil end portion 7a.

[0022] As shown in Figure 4(b), the pressing jig 8 is pressed from the second coil end portion 7a toward the first coil end portion 6a. By pressing and clamping the coil end portions until the welded connection portion 10 is formed, the end face 7c of the second coil end portion 7a remains in contact with the opposing face 6b of the first coil end portion 6a. In this way, a contact area is formed before the welded connection portion 10 is formed.

[0023] As shown in Figure 4(c), the laser 9 is irradiated onto the area (ridge) defined by the contact between the end face 7c of the second coil end portion 7a and the opposing surface 6b of the first coil end portion 6a to form the welded connection portion 10.

[0024] Through the methods described above, the contact state between the coil ends is standardized, which stabilizes the orientation and volume of the welded area. Furthermore, the heat input and melting amount are stabilized when forming the welded connection 10, and spatter can also be suppressed, resulting in stable welding quality.

[0025] Although the welding of the welded connection 10 is performed by keyhole welding, other welding methods may also be used.

[0026] (First modified example, second modified example) (Figure 5) Figure 5(a) is a diagram illustrating the first modified example, and Figure 5(b) is a diagram illustrating the second modified example. As shown in Figure 5(a), when the second coil end portion 7a contacts the opposing surface 6b of the first coil end portion 6a, stable welding quality can be ensured even if the central axis 16 of the first coil end portion 6a and the central axis 17 of the second coil end portion 7a do not overlap. Specifically, with the first coil end portion 6a fixed, the second coil end portion 7a may be tilted in the circumferential direction and brought into contact with the first coil end portion 6a.

[0027] Furthermore, as shown in Figure 5(b), the central axis 16 of the first coil end portion 6a and the central axis 17 of the second coil end portion 7a do not overlap with each other, and the first coil end portion 6a and the second coil end portion 7a are tilted relative to each other in the circumferential direction. The central axes 16 and 17 are not parallel to the axial direction 11 of the stator core. Specifically, the first coil end portion 6a may be tilted to one side in the circumferential direction, and the second coil end portion 7a may be tilted to the other side in the circumferential direction, so as to contact the first coil end portion 6a.

[0028] According to the embodiments of the present invention described above, the following effects and advantages are achieved.

[0029] (1) A method for manufacturing a stator 1 of a rotating electric machine 100, comprising an annular stator core 1a in which slots 4 are formed, and coils 3 that penetrate the slots 4 and have a rectangular cross-section, wherein each coil 3 has a coil end portion that protrudes axially outward from the stator core 1a and a welded connection portion 10 that is joined to other coils 3, wherein a plurality of slots 4 are formed along the circumferential direction of the stator core 1a, the plurality of coils 3 are inserted along the radial direction of the slots 4, and the coil end portion includes a first coil end portion 6a which is the coil end portion of a first coil among the coils 3, and a second coil end portion 7a which is the coil end portion of a second coil adjacent to the first coil, and the first coil end portion 6a and the second coil The coil end portion 7a comprises opposing surfaces 6b (7b) that face each other and an end surface 6c (7c) that protrudes axially outward. By inclining the second coil end portion 7a with respect to the first coil end portion 6a, the opposing surface 6b of the first coil end portion 6a and the end surface 7c of the second coil end portion 7a are brought into contact. A laser 9 with an inclination angle α relative to the opposing surface 6b of the first coil end portion 6a is irradiated from the torch 9a to the area defined by the contact between the opposing surface 6b of the first coil end portion 6a and the end surface 7c of the second coil end portion 7a, thereby forming a welded joint portion 10. During the formation process of the welded joint portion 10, the torch 9a is driven in at least one direction of the radial and circumferential directions. In this way, a method for manufacturing the stator 1 of a rotating electric machine 100 can be provided that stabilizes welding quality and shortens welding time.

[0030] (2) On the opposing surface of the first coil end portion 6a, when L1 is the shortest distance from the stator core 1a to the position furthest from the stator core 1a, and L2 is the shortest distance from the stator core 1a to the welded connection portion 10, L1 > L2. This makes it possible to stabilize the welding quality.

[0031] (3) The torch 9a is driven axially to irradiate the welding connection portion 10 of the second coil end portion 7a with a laser. In this way, the welding connection of one coil 3 for the rotating electric machine can be made while stabilizing the welding quality.

[0032] (4) By shearing the coil 3, an end face with burrs and sag is formed, and the side with the sag at the end face 7c of the second coil end portion 7a is brought into contact with the first coil end portion 6a. This stabilizes the welding quality.

[0033] (5) The second coil end portion 7a is tilted in the circumferential direction to bring it into contact with the first coil end portion 6a. In this way, even if one of the coil end portions is tilted in the circumferential direction, the welding quality can be stabilized.

[0034] (6) The first coil end portion 6a is tilted to one side in the circumferential direction, and the second coil end portion 7a is tilted to the other side in the circumferential direction, so as to contact the first coil end portion 6a. In this way, the welding quality can be stabilized even if both coil end portions are tilted in the circumferential direction.

[0035] (7) The coil 3 comprises a conductor and an insulating coating 5 that covers at least a portion of the conductor, with a portion of the opposing surface 6b (7b) and the end surface 6c (7c) of the conductor exposed from the insulating coating 5. In this way, the welding connection can be completed quickly while ensuring insulation.

[0036] (8) A method for manufacturing a rotating electric machine 100, comprising an annular stator core 1a in which slots 4 are formed, and a coil 3 that penetrates the slots 4 and has a rectangular cross-section, wherein the coil 3 has a coil end portion that protrudes axially outward from the stator core 1a and a welded connection portion 10 that is joined to other coils, wherein a plurality of slots 4 are formed along the circumferential direction of the stator core 1a, the plurality of coils 3 are inserted along the radial direction of the slots 4, and the coil end portion includes a first coil end portion 6a which is the coil end portion of a first coil 6 among the coils 3, and a second coil end portion 7a which is the coil end portion of a second coil 7 adjacent to the first coil 6, and the first coil end portion 6a and the second coil end The end portion 7a comprises opposing surfaces 6b (7b) that face each other and an end surface 6c (7c) that protrudes axially outward. By inclining the second coil end portion 7a with respect to the first coil end portion 6a, the opposing surface 6b of the first coil end portion 6a and the end surface 7c of the second coil end portion 7a are brought into contact. A laser 9 with an inclination angle α relative to the opposing surface 6b of the first coil end portion 6a is irradiated from the torch 9a to the area defined by the contact between the opposing surface 6b of the first coil end portion 6a and the end surface 7c of the second coil end portion 7a, thereby forming a welded joint 10. During the formation process of the welded joint 10, the torch 9a is driven in at least one direction of the radial and circumferential directions. In this way, a manufacturing method for a rotating electric machine 100 that stabilizes welding quality and shortens welding time can be provided.

[0037] It should be noted that the present invention is not limited to the embodiments described above, and various modifications and combinations of other configurations can be made without departing from the spirit of the invention. Furthermore, the present invention is not limited to having all the configurations described in the embodiments described above, and may also include configurations in which some of those configurations are omitted.

[0038] 1 Stator 1a Stator core 2 Rotor 3 Coil 4 Slot 5 Insulation coating 6 First coil 6a First coil end 6b Opposing surface 6c End face 6d Centerline 7 Second coil 7a Second coil end 7b Opposing surface 7c End face 7d Centerline 8 Pressing jig 9 Laser 9a Welding torch 10 Welding connection 11 Axial direction of stator core 16 First coil center axis 17 Second coil center axis 100 Rotating electric machine

Claims

1. A method for manufacturing a stator of a rotating electric machine, comprising: an annular stator core having slots formed therein; and coils penetrating the slots and having a rectangular cross-section, wherein each coil has a coil end portion projecting axially outward from the stator core and a welded connection portion joined to another coil, wherein a plurality of slots are formed along the circumferential direction of the stator core; the plurality of coils are inserted along the radial direction of the slots; the coil end portion includes a first coil end portion which is the coil end portion of a first coil and a second coil end portion which is the coil end portion of a second coil adjacent to the first coil; the first coil end portion and the second coil end portion each have an opposing surface which is a surface facing each other and an end surface which is a tip surface projecting axially outward; and the second coil end portion is inclined with respect to the first coil end portion so that the opposing surface of the first coil end portion and the end surface of the second coil end portion come into contact. A method for manufacturing a stator of a rotating electric machine, comprising: irradiating a range defined by the contact between the opposing surface of the first coil end and the end surface of the second coil end from a torch with a laser at an inclination angle α relative to the opposing surface of the first coil end to form the welded joint; and driving the torch in at least one direction of the radial and circumferential directions during the process of forming the welded joint.

2. A method for manufacturing a stator of a rotating electric machine according to claim 1, wherein, on the opposing surface of the first coil end portion, L1 is the shortest distance from the stator core to the position furthest from the stator core with respect to the stator core, and L2 is the shortest distance from the stator core to the welded connection portion, and L1 > L2.

3. A method for manufacturing a stator of a rotating electric machine according to claim 1, wherein the torch is driven in the axial direction and the laser is irradiated toward the welding connection portion of the second coil end portion.

4. A method for manufacturing a stator of a rotating electric machine according to claim 1, wherein the coil is sheared to form the end face having burrs and sag, and the end face of the second coil end portion having the sag is brought into contact with the first coil end portion.

5. A method for manufacturing a stator of a rotating electric machine according to claim 1, wherein the second coil end portion is inclined in the circumferential direction and brought into contact with the first coil end portion.

6. A method for manufacturing a stator of a rotating electric machine according to claim 5, wherein the first coil end portion is inclined to one side in the circumferential direction, and the second coil end portion is inclined to the other side in the circumferential direction and brought into contact with the first coil end portion.

7. A method for manufacturing a stator of a rotating electric machine according to claim 1, wherein the coil comprises a conductor and an insulating coating covering at least a portion of the conductor, and the method for manufacturing a stator of a rotating electric machine wherein a portion of the opposing surface and the end surface of the conductor are exposed from the insulating coating.

8. A method for manufacturing a rotating electric machine, comprising: an annular stator core having slots formed therein; a coil penetrating the slots and having a rectangular cross-section, wherein the coil has a coil end portion projecting axially outward from the stator core and a welded connection portion joined to another coil, wherein a plurality of slots are formed along the circumferential direction of the stator core; the plurality of coils are inserted along the radial direction of the slots; the coil end portion includes a first coil end portion which is the coil end portion of a first coil and a second coil end portion which is the coil end portion of a second coil adjacent to the first coil; the first coil end portion and the second coil end portion each have an opposing surface which is a surface that faces each other and an end surface which is a tip that projects axially outward; and the second coil end portion is tilted relative to the first coil end portion so that the opposing surface of the first coil end portion and the end surface of the second coil end portion come into contact. A method for manufacturing a rotating electric machine, wherein a laser with an inclination angle α relative to the opposing surface of the first coil end is irradiated from a torch to an area defined by the contact between the opposing surface of the first coil end and the end surface of the second coil end to form the welded joint, and the torch is driven in at least one direction of the radial and circumferential directions during the process of forming the welded joint.

Images