JP2020142257A - Laser welding method, laser welding device, and manufacturing method of rotating electric machine - Google Patents

Abstract

To join easily each end of electric conductors by using a laser beam, without requiring highly-accurate butting of each end of the electric conductors.SOLUTION: A laser welding method for joining each end 41 of two electric conductors 40 by laser welding, has a melting step for melting each end 41 separately by irradiating a laser beam 61 to each end 41 of the two electric conductors 40, and forming a molten part 42 on each end 41 respectively, and a bonding step for bonding each molten part 42 under melting of each end 41 of the two electric conductors 40.SELECTED DRAWING: Figure 7

Description

The present invention relates to a laser welding method, a laser welding apparatus, and a method for manufacturing a rotary electric machine.

Conventionally, rotary electric motors such as electric motors and generators having a stator and a rotor are known. The stator of a rotary electric machine is usually manufactured as follows.
First, a plurality of coil elements formed by bundling a plurality of electric conductors into a substantially U shape are produced. Next, the plurality of manufactured coil elements are aligned in an annular shape while being overlapped in the circumferential direction, and in this state, the two ends of each electric conductor are inserted into the respective slots provided in the annular shape on the stator core. Next, the ends of the electric conductors protruding from each slot are twisted and bent in the circumferential direction, and then the ends are electrically joined to each other. As a result, the stator of the rotary electric machine is manufactured.

By the way, TIG welding has been widely used as a method of electrically joining the ends of a plurality of electric conductors, but in recent years, laser welding that does not require a ground electrode and can obtain high energy efficiency has been studied. ing.

For example, in Patent Document 1, before welding the ends of electric conductors to each other, the ends are pressed toward each other by a compression device to bring them into close contact with each other, and then laser light is irradiated over the ends. Therefore, it is disclosed that a molten metal bath is formed over the tip surface of a closely contacted end portion, and after the molten metal bath is cooled, the pressing of the end portion is released. In this case, the laser beam is emitted along a welding line orthogonal to the common edge portion in which the ends are in contact with each other and extending through the common edge portion itself.

JP-A-2016-208829

As in the conventional case, when an external force is applied to the ends of two electric conductors before welding to bring the ends into close contact with each other and the laser light is irradiated over the ends, the irradiated laser light is the electric conductor. In order to prevent the ends of the electric conductors from coming off between the ends, it is necessary to bring the ends of the electric conductors into close contact with each other without a gap and maintain the close contact until the welding is completed.

However, in the welding of electric conductors of rotary electric machines, the space around the ends of the electric conductors is generally narrow, so a mechanism corresponding to the difficult operation of closely abutting the ends without gaps should be arranged. Has the problem that it is difficult.

The present invention has been made in view of the above, and an object of the present invention is to easily join the ends of electric conductors to each other by using a laser beam without having to abut the ends of the electric conductors with high precision. It is an object of the present invention to provide a laser welding method, a laser welding apparatus, and a method for manufacturing a rotary electric machine.

(1) The laser welding method according to the present invention is a laser welding method in which the ends (for example, the end 41 described later) of two electric conductors (for example, the electric conductor 40 described later) are joined by laser welding. Then, the ends of the two electric conductors are irradiated with a laser beam (for example, the laser beam 61 described later) to melt the ends separately, and the melting portion (for example, the melting portion described later) is formed on the ends. It has a melting step of forming each of 42) and a joining step of joining the molten portions during melting of the ends of the two electric conductors.

According to the configuration of (1) above, since the ends of the two electric conductors are separately melted by the laser beam, the laser beam does not escape between the ends. Further, since the molten portions that are being melted are bonded to each other after the fused portions are formed, it is not necessary to abut the ends of the two electric conductors with high accuracy without any gaps, and the ends can be easily joined to each other. It can be carried out.

(2) In the laser welding method according to (1), in the bonding step, an external force is mechanically applied to the end portions so that the molten portions approach each other (for example, a pressing mechanism 5 described later is used). Therefore, the molten portions being melted may be bonded to each other.

According to the configuration of (2) above, the molten portions at the ends can be easily joined to each other. Moreover, since the molten portions can be connected to each other with a small pressing force, the structure for applying a mechanical external force can be simple.

(3) In the laser welding method according to (1), in the bonding step, an external force is electrically applied to the molten portion (for example, a magnetic field generators 7 and 7A described later are used) to perform melting. The molten portions may be bonded to each other.

According to the configuration of (3) above, the molten portions at the ends can be easily joined to each other without depending on a mechanical mechanism.

(4) In the laser welding method according to (1), in the melting step, the ends of the two electric conductors are irradiated with separate laser beams, and in the bonding step, the melting portion being melted is irradiated. The molten portions may be bonded to each other by bringing the laser beams irradiating close to each other and inclining the molten portions so that the fused portions approach each other.

According to the configuration of (4) above, the molten portions at the ends can be easily coupled to each other only by irradiating the laser beam without depending on the mechanical and electrical mechanisms.

(5) The laser welding apparatus according to the present invention is a laser welding apparatus (for example, a laser welding apparatus for joining two end portions (for example, the end portion 41 described later) of two electric conductors (for example, the electric conductor 40 described later) by laser welding. In the laser welding apparatus 100) described later, the ends of the two electric conductors are each irradiated with a laser beam (for example, the laser beam 61 described later) to irradiate the molten portion (for example, the fused portion 42 described later). Laser irradiation means (for example, laser irradiation means 6 and 6A described later) that separately melt the ends so as to form the respective ends, and the melting during melting formed at the ends of the two electric conductors. It is provided with a coupling means (for example, a pressing mechanism 5 described later, a magnetic field generators 7 and 7A) for coupling the portions.

According to the configuration of (5) above, since the ends of the two electric conductors can be separately melted by the laser beam, the laser beam does not escape between the ends. Further, since the molten portions are coupled to each other, it is not necessary to abut the ends of the two electric conductors with high accuracy without gaps, and the ends can be easily joined to each other.

(6) In the method for manufacturing a rotary electric machine according to the present invention, a plurality of electric wires are inserted into each slot (for example, slot 2a described later) provided in a stator core (for example, a stator core 2 described later) and protrude from each slot. It is a manufacturing method of a rotary electric machine that manufactures a rotary electric machine by joining the ends (for example, the end 41 described later) of a conductor (for example, an electric conductor 40 described later) to each other by laser welding, and protrudes from each slot. The ends of the two electric conductors are joined by the laser welding method according to any one of (1) to (4).

According to the configuration (6) above, it is not necessary to abut the ends of the electric conductors constituting the rotary electric machine with high accuracy, and the ends of the electric conductors can be easily joined by using a laser beam.

According to the present invention, a laser welding method, a laser welding apparatus, and a rotary electric machine that can easily join the ends of electric conductors to each other by using laser light without having to abut the ends of electric conductors with high precision. Manufacturing method can be provided.

It is a perspective view which shows the structure of the stator of the rotary electric machine which concerns on one Embodiment of this invention. It is a figure which shows the state when a plurality of coil elements in the stator of the rotary electric machine which concerns on one Embodiment of this invention are inserted into each slot of a stator core. It is a perspective view which shows the end part of the plurality of electric conductors in the stator of the rotary electric machine which concerns on one Embodiment of this invention. It is a figure which shows typically the end part of two electric conductors to be bonded. It is a figure which shows typically the state of irradiating each end portion of an electric conductor with a laser beam. It is a figure which shows one Embodiment of a laser irradiation means schematically. It is a figure which shows typically another embodiment of a laser irradiation means. It is a figure which shows typically the appearance that the molten part was formed at the end part of the electric conductor by the irradiation of a laser beam. It is a figure which shows typically the state of connecting the molten part of the end part of an electric conductor. It is a figure which shows typically the state in which the molten part of the end part of an electric conductor is bonded to each other. It is a figure which shows typically one Embodiment of the coupling means which bonds the molten part with each other by applying an electric external force. It is a figure which shows typically another embodiment of the coupling means which bonds the molten part with each other by applying an electric external force. It is a figure which shows typically how the molten part of the end part of an electric conductor is bonded to each other by another method. It is a figure which shows typically the state of irradiating the end portion of an electric conductor with a laser beam by another method.

Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.
The method for manufacturing a rotary electric machine according to the present embodiment is to manufacture a rotary electric machine by inserting the rotary electric machine into each slot provided in the stator core and joining the ends of a plurality of electric conductors protruding from the respective slots by laser welding. To do.

First, the configuration of the rotary electric machine manufactured by the manufacturing method according to the present embodiment will be described.
FIG. 1 is a perspective view showing a configuration of a stator 1 of a rotary electric machine according to the present embodiment. As shown in FIG. 1, the stator 1 is formed in a cylindrical shape. A rotor (not shown) is rotatably arranged inside the stator 1, thereby forming a rotary electric machine.

The stator 1 includes a stator core 2 and a coil 3. The stator core 2 is formed in a cylindrical shape. The stator core 2 is provided with a plurality of slots 2a penetrating in the direction of the rotation axis in an annular shape. That is, a plurality of slots 2a are provided at equal intervals in the circumferential direction of the stator core 2. Each slot 2a is formed so that the radial cross-sectional shape of the stator core 2 extends radially from the center side of the stator core 2. Each slot 2a communicates with the inner peripheral surface of the stator core 2 via slits 2b formed inside the stator core 2 at equal intervals in the circumferential direction, but the slits 2b are not essential.

The coil 3 is obtained by joining a plurality of coil elements 4 obtained by bundling a plurality of electric conductors made of copper, for example, into a substantially U shape by laser welding.
Here, FIG. 2 is a diagram showing a state when a plurality of coil elements 4 are inserted into the respective slots 2a of the stator core 2. As shown in FIG. 2, in the coil 3, a plurality of coil elements 4 each of which are formed of electric conductors formed in a substantially U shape are arranged in an annular shape while being overlapped in the circumferential direction, and the ends of the electric conductors are aligned. After inserting the portion (lower end portion in FIG. 2) into each slot 2a along the axial direction (vertical direction in FIG. 2) of the stator core 2, the end portion of the electric conductor protruding from the side opposite to the insertion side into each slot 2a. Is obtained by laser welding. Laser welding of the ends of the electrical conductors is performed on the ends of the two electrical conductors that project from slot 2a and are juxtaposed.

Next, an embodiment of a specific method of laser welding the ends of the electric conductors of the coil element 4 will be described. The laser welding method according to the present embodiment includes a melting step and a joining step.
Here, FIG. 3 is a perspective view showing the ends of a plurality of electric conductors in the stator of the rotary electric machine according to the embodiment of the present invention. FIG. 3 shows a state in which the stator core 2 shown in FIGS. 1 and 2 is inverted in the axial direction.

As shown in FIG. 3, the end portions 41 of the plurality of electric conductors 40 inserted into the respective slots 2a of the stator core 2 project from the respective slots 2a on the opposite side to the insertion side. First, prior to the melting step, the ends 41 of the electric conductors 40 adjacent to each other in the radial direction of the stator core 2 are aligned at the ends 41 of the plurality of electric conductors 40.

Next, the end portions 41 of the plurality of electric conductors 40 protruding from each slot 2a are twisted and bent in the circumferential direction (left-right direction in FIG. 3) of the stator core 2. Specifically, after twisting the end 41 of the electric conductor 40 in the circumferential direction, the most advanced portion thereof is bent in the axial direction (vertical direction in FIG. 3) of the stator core 2 in the direction opposite to the slot 2a.

More specifically, the end 41 of the outermost electric conductor 40 is twisted to one side in the circumferential direction (clockwise in FIG. 3). Next, the end 41 of the second and third electric conductors 40 from the outside is twisted to the other side in the circumferential direction (counterclockwise in FIG. 3). Next, the end 41 of the fourth and fifth electric conductors 40 from the outside is twisted to one side in the circumferential direction (clockwise in FIG. 3). After alternately twisting in the opposite directions in this way, finally, the end 41 of the innermost electric conductor 40 is twisted to one side in the circumferential direction (clockwise in FIG. 3).

By twisting the end portions 41 of the plurality of electric conductors 40 in this way, the end portions 41, 41 of the two adjacent electric conductors 40, 40 are aligned and juxtaposed in the radial direction. The ends 41, 41 of the two electric conductors 40, 40 juxtaposed along the radial direction are the ends to be bonded to each other in the bonding step described later. The heights of the end portions 41 (protruding length from the slot 2a) of the two end portions 41, 41 of the two electric conductors 40, 40 to be coupled are also the same. Therefore, the tip surfaces of the end portions 41, 41 of the two electric conductors 40, 40 are arranged on substantially the same surface.

In the melting step of the present embodiment, in the plurality of coil elements 4 inserted and aligned in the respective slots 2a of the stator core 2 in this way, the two coil elements 4 project to the side opposite to the insertion side into the respective slots 2a and are to be coupled. The ends 41 and 41 of the electric conductors 40 and 40 of the above are irradiated with laser light, respectively. The ends 41, 41 of the two electric conductors 40, 40 do not necessarily have to be in contact with each other, and need only be close to each other with a slight separation distance. That is, the ends 41, 41 of the two electric conductors 40, 40 to be coupled need to be closely abutted against each other by applying an external force by some mechanism at the start of laser irradiation. Absent.

A method of melting the end portions 41 with a laser beam in the melting step of the present embodiment will be further described with reference to FIGS. 4 to 8. FIG. 4 is a diagram schematically showing the ends of the two electric conductors to be coupled. FIG. 5 is a diagram schematically showing how laser light is irradiated to each end of an electric conductor. FIG. 6 is a diagram schematically showing an embodiment of the laser irradiation means. FIG. 7 is a diagram schematically showing another embodiment of the laser irradiation means. FIG. 8 is a diagram schematically showing how a molten portion is formed at each end of an electric conductor by irradiation with a laser beam.
4 to 8 show the ends 41, 41 of the two electric conductors 40, 40 protruding from the slot 2a (not shown in FIG. 4) and juxtaposed.

In the melting step, the laser welding device 100 is used when laser welding the ends 41, 41 of the two electric conductors 40, 40 to each other. The laser welding device 100 irradiates the ends 41 and 41 of the two electric conductors 40 and 40 with laser light 61 and 61, respectively, and melts the ends 41 and 41 separately so as to form the molten portion 42, respectively. It is provided with a laser irradiating means 6 for causing the laser irradiation, and a coupling means for bonding the molten portions 42, 42 formed at the ends 41, 41 of the two electric conductors 40, 40, respectively.

As shown in FIGS. 4, 5 and 8, a pressing mechanism 5 which is an embodiment of the coupling means is arranged in the vicinity of the ends 41 and 41 of the two electric conductors 40 and 40. The pressing mechanism 5 has a pair of pressing portions 51, 51 formed in a thin flat plate shape, for example, which can be easily inserted between the end portions 41, 41 of the adjacent electric conductors 40, 40. The ends 41, 41 of the two electric conductors 40, 40 to be coupled are sandwiched between the pair of pressing portions 51, 51. However, in the melting step of the present embodiment, the pressing portions 51, 51 of the pressing mechanism 5 have not yet applied a pressing force in the direction of approaching the ends 41, 41 of the electric conductors 40, 40. ..

In FIG. 5, the laser irradiation means 6 is shown above the ends 41, 41 of the two electric conductors 40, 40 juxtaposed. The laser irradiation means 6 has two laser irradiation units 60, 60 capable of irradiating the laser beams 61, 61 toward the ends 41, 41, respectively, in a one-to-one correspondence with the two electric conductors 40, 40. Have.

The specific type of the laser irradiation unit 60 is not limited, and for example, the laser irradiation device 60A composed of the scanner head shown in FIG. 6 and the laser irradiation device 60B composed of the laser head shown in FIG. 7 can be used. .. According to the laser irradiation device 60A composed of a scanner head, only the laser beam 61 can be changed in an arbitrary direction by changing the angle of a mirror (for example, a galvano mirror) provided inside (for example, a galvano mirror). .. According to the laser irradiation device 60B composed of the laser head, the laser irradiation means 6 can be compactly configured.

Further, the type of the laser beam 61 emitted from the laser irradiation unit 60 toward the end portion 41 is not limited, and for example, a fiber laser, a YAG laser, a CO ₂ laser, a semiconductor excitation laser, or the like can be used.

In the melting step of the present embodiment, the ends 41 and 41 are melted separately at the same time by irradiating the ends 41 and 41 with different laser beams 61 and 61 from these laser irradiation units 60 and 60, respectively. That is, since the laser beam 61 is not irradiated over the ends 41 and 41, the laser beam 61 is between the ends 41 and 41 even if the ends 41 and 41 are not closely abutted against each other. There is no risk of it falling out.

As shown in FIGS. 4 and 5, the laser beam 61 irradiating the end 41 of the electric conductor 40 covers a region of the tip surfaces of the end 41 including at least the inner edges 41a or the inner edges 41a facing each other. It is melted to form a melted portion made of molten metal in a region including at least the inner edge 41a or the inner edge 41a where the ends 41 and 41 face each other. Melting the region including the inner edge 41a or the inner edge 41a in which at least the ends 41 and 41 face each other is to be joined when the melted portions of the ends 41 and 41 are brought close to each other in a later joining step. This is to make it easier to make. That is, the molten portion melts at least the region including the opposite inner edges 41a or the inner edges 41a of the ends 41, 41, so that when the ends 41, 41 are brought close to each other, the fused portions come into direct contact with each other. Formed to get.

In the melting step, the end portion 41 may be melted as a whole. In the melting step of the present embodiment, the ends 41 and 41 are separately irradiated with the laser beams 61 and 61 to melt the entire ends 41 and 41 separately, so that the ends 41 are formed as shown in FIG. , 41 are formed with molten portions 42 and 42 composed of molten spheres 42a and 42a in which the metal is melted in a spherical shape, respectively.

Next, in the bonding step of the present embodiment, the molten portions 42, 42 formed at the end portions 41, 41 in the melting step are bonded to each other. This joining step will be further described with reference to FIGS. 9 and 10. FIG. 9 is a diagram schematically showing how the molten portions at the ends of the electric conductor are coupled to each other. FIG. 10 is a diagram schematically showing a state in which the molten portions at the ends of the electric conductor are bonded to each other.

The molten portions 42, 42 of the end portions 41, 41 to be coupled in the bonding step of the present embodiment are still fused portions during melting. Here, “during melting” means that even after the molten portion 42 is formed by irradiating the laser beam 61 from the laser irradiation unit 60, the molten portion 42 is not cooled and solidified by continuing the irradiation of the laser beam 61. , Means that the molten state is maintained. Therefore, although the laser irradiation means 6 is not shown in FIGS. 8 and 9, the molten portions 42 and 42 in FIGS. 8 and 9 are also irradiated with the laser beams 61 and 61 from the laser irradiation portions 60 and 60, respectively. As a result, the molten portions 42 and 42 are still in a molten state.

The molten portions 42, 42 during melting of the end portions 41, 41 are naturally bonded as the molten portions 42 grow, when the end portions 41, 41 are juxtaposed with each other sufficiently close to each other. It is also possible to do so. However, for the purpose of more reliably binding the molten portions 42, 42 to each other, an external force is applied to the end portions 41, 41 so that the molten portions 42, 42 approach each other, thereby causing the molten portions 42, 42 to be melted. It is desirable to connect them together.

In the present embodiment shown in FIGS. 4, 5, 8 and 9, the melted portions 42, 42 formed at the ends 41, 41 of the two electric conductors 40, 40 are coupled to each other. As the coupling means, a pressing mechanism 5 that mechanically applies an external force to the ends 41 and 41 is exemplified. In the coupling step of the present embodiment, the pressing portions 51, 51 of the pressing mechanism 5 are applied to the ends 41, 41 of the two electric conductors 40, 40 by, for example, pneumatic pressure, hydraulic pressure, driving force of a motor, or the like. A pressing force is applied to the ends 41 and 41 in a direction approaching each other. At this time, the two pressing portions 51 and 51 may be moved, respectively, or only one pressing portion 51 may be moved toward the other pressing portion 51.

The molten portions 42, 42 during melting come into contact with each other in the process of being pressed by the pressing portions 51, 51 and moving so that the end portions 41, 41 approach each other. As a result, a united metal portion 43 in which the molten portions 42, 42 are united is formed at the end portions 41, 41 of the two electric conductors 40, 40. FIG. 10 shows a state in which a coalesced metal portion 43 made of one large metal sphere is formed by bonding the molten portions 42, 42 that are melted in a spherical shape to each other. After the end of laser irradiation, the end portions 41, 41 of the two electric conductors 40, 40 are integrated by cooling and solidifying the combined metal portion 43, and are electrically joined.

According to the laser welding method and the laser welding apparatus 100 of the present embodiment in which the ends 41, 41 of the two electric conductors 40, 40 are laser-welded to each other in this way, the end portions 41 of the two electric conductors 40, 40 , 41 are separately melted by the laser beams 61 and 61, so that the laser beam 61 does not escape between the ends 41 and 41. Moreover, since the molten portions 42, 42 that are being melted are coupled to each other after the molten portions 42, 42 are formed, the ends 41, 41 of the two electric conductors 40, 40 are butted with high accuracy without any gaps. There is no need, and the ends 41, 41 can be easily joined to each other.

Further, the pressing force as a mechanical external force applied to the ends 41 and 41 by the pressing mechanism 5 causes the molten portions 42 and 42 of the ends 41 and 41 of the two electric conductors 40 and 40 to come into close contact with each other. A small force that slightly moves the ends 41, 41 is sufficient. Moreover, the pressing mechanism 5 does not require high accuracy such that the ends 41, 41 of the two electric conductors 40, 40 are closely abutted against each other. Therefore, the structure of the pressing mechanism 5 can be simple.

In the joining step, the method of joining the molten portions 42, 42 during melting is a method of applying a mechanical external force to the ends 41, 41 by using the pressing mechanism 5 as the coupling means as described above. Not limited to. For example, the molten portions 42, 42 during melting may be bonded to each other by electrically applying an external force to the molten portions 42, 42.

FIG. 11 is a diagram schematically showing an embodiment of a coupling means for coupling molten portions to each other by applying an electric external force. The coupling means shown in FIG. 11 is composed of a magnetic field generator 7. The magnetic field generator 7 includes two magnetic field generating coils 71, 71, one control device 72 including a power source for supplying electric power to the magnetic field generating coils 71, 71, and two pairs of energizing probes 73a, 73b, 73a, 73b. It has two power supplies 74, 74 that supply power to each of the energizing probes 73a, 73b.

The two magnetic field generating coils 71 and 71 are arranged above and below the ends 41 and 41 of the two electric conductors 40 and 40 to be coupled, respectively. The two magnetic field generating coils 71, 71 are arranged so as to be aligned on the same axis, and the ends 41 of the two electric conductors 40, 40 are arranged on or near the axis between the two magnetic field generating coils 71, 71. , 41 are juxtaposed. The two magnetic field generating coils 71 and 71 are configured to generate a magnetic field from the bottom to the top between them in the present embodiment by being supplied with electric power from the control device 72, respectively.

In FIG. 11, the molten portions 42 and 42 of the end portions 41 and 41 are omitted for simplification of the illustration. Since the magnetic field generator 7 is arranged with respect to the two electric conductors 40, 40 before the melting step, in the melting step, for example, the laser beam 61 is passed through the center of the upper magnetic field generating coil 71 to the ends 41, 41. Is irradiated, and the molten portions 42, 42 are formed.

The two pairs of energizing probes 73a, 73b, 73a, 73b are provided corresponding to the two electric conductors 40, 40. The energizing probes 73a and 73b are arranged so as to sandwich the end 41 of the electric conductor 40 from both sides in the alignment direction of the ends 41 and 41. In the present embodiment, the two pairs of energizing probes 73a, 73b, 73a, 73b are supplied with electric power from the power supplies 74 and 74, respectively, so that the ends 41 and 41 are energized from one energizing probe 73a to the other. A current is applied toward the probe 73b in a direction orthogonal to the alignment direction of the ends 41 and 41. As shown in FIG. 11, the positions of the energizing probe 73a and the energizing probe 73b that sandwich the end portion 41 are arranged so as to be opposite to each other at the end portions 41 and 41. Therefore, currents flowing in opposite directions are applied to the ends 41, 41 of the two electric conductors 40, 40 along the directions orthogonal to the alignment direction of the ends 41, 41. There is.

In this magnetic field generator 7, two pairs of energizing probes 73a, 73b, 73a, 73b are used in a state where a magnetic field is applied from the bottom to the top with respect to the ends 41, 41 of the two electric conductors 40, 40. When a current flowing in opposite directions is applied to the ends 41 and 41, the melting portions 42 and 42 (not shown in FIG. 11) of the ends 41 and 41 are attracted to each other by Lorentz force. Electrical forces F and F are applied. At this time, since the molten portions 42 and 42 are being melted, the centers of gravity of the fused portions 42 and 42 move in the direction of approaching each other and are coupled by applying the electric forces F and F. After that, the molten portions 42, 42 cool and harden, so that the two electric conductors 40, 40 are electrically connected.

Since the electrical forces F and F due to the Lorentz force are smaller than the mechanical pressing force, it is difficult to combine them with the electrical forces F and F alone because the molten portions 42 and 42 are small and the like. In this case, as shown in FIG. 12, a magnetic field generator 7A having energizing probes 75a and 75b with a pressing function may be used to assist the contact and coupling between the molten portions 42 and 42. In this magnetic field generator 7A, only one of the pair of energizing probes 75a and 75b (the energizing probes 75a and 75b on the front side in FIG. 12) can apply an external force in the pressing direction to the end portion 41. One of these energizing probes 75a and 75b is arranged so as to abut the ends 41 and 41 from the outside in the arrangement direction of the ends 41 and 41, respectively. One of these energizing probes 75a and 75b is connected to a pressing mechanism (not shown), and the tips of these energizing probes 75a and 75b apply an external force to the ends 41 and 41 in a direction approaching each other. This external force is only an auxiliary force of the electrical forces F and F, and is extremely weak as compared with the case where the molten portions 42 and 42 are coupled to each other only by the mechanical pressing force by the pressing mechanism 5 described above. This is sufficient, and there is no risk of increasing the size and complexity of the magnetic field generator 7A.

Further, as another method of connecting the molten portions 42, 42 during melting, as in the melting step in the present embodiment, the two electric conductors 40, 40 are separately separated from the end portions 41, 41. When the molten portions 42, 42 are formed by irradiating the laser irradiation portions 60, 60 of the above with separate laser beams 61, 61, the irradiation of the respective laser beams 61, 61 is performed as shown below. , A method of bonding the molten portions 42, 42 during melting can also be used.

FIG. 13 schematically shows how the molten portions 42, 42 of the end portions 41, 41 of the electric conductors 40, 40 are coupled to each other by a method different from the above method. In this method, in the coupling step, the laser irradiation units 60 and 60 are operated so that the laser beams 61 and 61 irradiating the melting portions 42 and 42 from the separate laser irradiation units 60 and 60 are close to each other. ..

Specifically, the laser beam 61 so that the irradiation points (focal positions) 61a, 61a on the surface of the molten portions 42, 42 in the laser beams 61, 61 irradiated to the fused portions 42, 42 are close to each other. , 61 are moved in the approaching direction. When the laser beams 61 and 61 move in this way, the centers of gravity of the molten portions 42 and 42 also move so as to be close to each other as the irradiation points 61a and 61a move, and the centers of gravity of the fused portions 42 and 42 move to the ends 41, It deviates from the center of 41 and deforms so that the molten portions 42, 42 during melting are tilted toward the center of gravity. As a result, as shown in FIG. 13, the molten portions 42, 42 being melted are tilted so that the molten portions 42, 42 approach each other. When the molten portions 42, 42 being melted are tilted to the extent that the molten portions 42, 42 come into contact with each other, the molten portions 42, 42 are coalesced to form one coalesced metal portion 43, as in FIG. The ends 41, 41 of the electric conductors 40, 40 of the book are electrically joined to each other.

According to this method, the molten portions 42, 42 of the end portions 41, 41 of the two electric conductors 40, 40 can be easily irradiated with the laser beam 61 without depending on the mechanical and electrical mechanisms. Since they can be combined, the structure of the laser welding apparatus 100 can be simplified.

In each of the above embodiments, the ends 41 and 41 of the two electric conductors 40 and 40 are irradiated with different laser beams 61 and 61 from the separate laser irradiation units 60 and 60 of the laser irradiation means 6. However, it is not limited to this. As in the laser irradiation means 6A shown in FIG. 14, even if the ends 41 and 41 of the two electric conductors 40 and 40 are irradiated with the laser beam 61 from one common laser irradiation unit 60, respectively. Good.

In this case, in the melting step, the laser beams 61 and 61 are individually irradiated from one laser irradiation unit 60 to the end portions 41 and 41, respectively. In the irradiation of the laser beam 61 from one laser irradiation unit 60, in order to prevent the laser beam 61 from passing between the ends 41 and 41, after irradiating one end 41, the irradiation is temporarily stopped. After that, the operation of irradiating the other end 41 is alternately performed on the ends 41 and 41. As shown in FIG. 14, the irradiation of the laser beam 61 to the ends 41 and 41 may be alternately switched so that the direction of the laser irradiation unit 60 itself faces the ends 41 and 41. For example, by using the scanner head shown in FIG. 6, only the emission direction of the laser beam 61 from the laser irradiation unit 60 may be alternately switched so as to face the end portions 41 and 41. According to this laser welding method and the laser welding apparatus, since only one laser irradiation unit 60 is required, the configuration for laser irradiation can be further simplified.

Further, in each embodiment, the pressing force is not applied to the two electric conductors 40, 40 before the laser irradiation. The electric conductors 40 and 40 may be pressed by a clamp jig (not shown) to irradiate the laser beam 61 with the peripheral and radial directions of the ends 41 and 41 appropriately positioned.

1 stator 2 stator core 2a slot 3 coil 4 coil element 40 electric conductor 41 end 42 fusion part 5 pressing mechanism (coupling means)
6,6A Laser irradiation means 61 Laser light 7,7A Magnetic field generator (coupling means)

Claims (6)

This is a laser welding method in which the ends of two electric conductors are joined by laser welding.
A melting step of irradiating the ends of the two electric conductors with a laser beam to melt the ends separately and forming a melted portion at each of the ends.
A laser welding method comprising a bonding step of bonding the molten portions during melting of the ends of the two electric conductors. The laser welding method according to claim 1, wherein in the bonding step, the molten portions are bonded to each other by mechanically applying an external force to the end portions so that the molten portions are brought close to each other. The laser welding method according to claim 1, wherein in the bonding step, the molten portions are bonded to each other by electrically applying an external force to the fused portions. In the melting step, the ends of the two electric conductors are irradiated with separate laser beams.
In the bonding step, the molten portions are bonded to each other by bringing the laser beams irradiating the molten portions close to each other and inclining the fused portions so that the fused portions approach each other. The laser welding method according to claim 1. A laser welding device that joins the ends of two electric conductors by laser welding.
A laser irradiation means that irradiates the ends of the two electric conductors with laser light and separately melts the ends so as to form a fused portion.
A laser welding apparatus including a coupling means for connecting the molten portions that are being melted, which are formed at the ends of the two electric conductors, respectively. It is a manufacturing method of a rotary electric machine that manufactures a rotary electric machine by joining the ends of a plurality of electric conductors that are inserted into each slot provided in the stator core and project from each slot by laser welding.
A method for manufacturing a rotary electric machine, wherein the ends of two electric conductors protruding from each slot are joined to each other by the laser welding method according to any one of claims 1 to 4.

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