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WO2024080097A1 - Procédé de fabrication de stator de machine électrique rotative et dispositif de fabrication de stator de machine électrique rotative - Google Patents

Procédé de fabrication de stator de machine électrique rotative et dispositif de fabrication de stator de machine électrique rotative Download PDF

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Publication number
WO2024080097A1
WO2024080097A1 PCT/JP2023/034370 JP2023034370W WO2024080097A1 WO 2024080097 A1 WO2024080097 A1 WO 2024080097A1 JP 2023034370 W JP2023034370 W JP 2023034370W WO 2024080097 A1 WO2024080097 A1 WO 2024080097A1
Authority
WO
WIPO (PCT)
Prior art keywords
laser beam
welding
electric machine
rotating electric
stator
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/JP2023/034370
Other languages
English (en)
Japanese (ja)
Inventor
英晴 牛田
泰輔 中村
泰守 中野
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Aisin Corp
Original Assignee
Aisin Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Aisin Corp filed Critical Aisin Corp
Priority to CN202380071356.1A priority Critical patent/CN120077557A/zh
Priority to DE112023003425.7T priority patent/DE112023003425T5/de
Priority to JP2024551360A priority patent/JPWO2024080097A1/ja
Publication of WO2024080097A1 publication Critical patent/WO2024080097A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K15/00—Processes or apparatus specially adapted for manufacturing, assembling, maintaining or repairing of dynamo-electric machines
    • H02K15/04—Processes or apparatus specially adapted for manufacturing, assembling, maintaining or repairing of dynamo-electric machines of windings prior to their mounting into the machines
    • H02K15/0414—Processes or apparatus specially adapted for manufacturing, assembling, maintaining or repairing of dynamo-electric machines of windings prior to their mounting into the machines the windings consisting of separate elements, e.g. bars, segments or half coils
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K26/00—Working by laser beam, e.g. welding, cutting or boring
    • B23K26/08—Devices involving relative movement between laser beam and workpiece
    • B23K26/082—Scanning systems, i.e. devices involving movement of the laser beam relative to the laser head
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K26/00—Working by laser beam, e.g. welding, cutting or boring
    • B23K26/20—Bonding
    • B23K26/21—Bonding by welding
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K2101/00—Articles made by soldering, welding or cutting
    • B23K2101/36—Electric or electronic devices
    • B23K2101/38—Conductors
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K2213/00—Specific aspects, not otherwise provided for and not covered by codes H02K2201/00 - H02K2211/00
    • H02K2213/03—Machines characterised by numerical values, ranges, mathematical expressions or similar information

Definitions

  • This disclosure relates to a method and an apparatus for manufacturing a stator for a rotating electric machine.
  • a technology is known that achieves welding between coil pieces by bringing the tips of one coil piece and another coil piece into contact with each other and scanning a laser beam in a loop while moving it in a direction that includes a directional component parallel to the contact surface of the tips.
  • the loop pitch depending on the relationship between the beam diameter of the laser beam and the amount of movement in the forward direction per one loop-shaped scan (hereinafter also referred to simply as the "loop pitch"), it is difficult to efficiently achieve high-quality welding. For example, if the loop pitch is too large compared to the beam diameter of the laser beam, the molten pool cannot be properly maintained, and there is a risk of reduced welding quality. Also, if the loop pitch is too small compared to the beam diameter of the laser beam, there is a risk of excessive welding time and heat input per unit length of the area to be welded.
  • the present disclosure aims to efficiently achieve high-quality welding between coil pieces of a stator for a rotating electric machine.
  • the method for manufacturing a stator for a rotating electric machine is provided, wherein the amount of movement in the traveling direction per one loop-shaped scan is equal to or smaller than the beam diameter of the laser beam.
  • the present disclosure makes it possible to efficiently achieve high-quality welding between coil pieces of a stator for a rotating electric machine.
  • FIG. 1 is a cross-sectional view showing a schematic cross-sectional structure of a motor according to an embodiment
  • FIG. 2 is a plan view of the stator core in a single component state.
  • 3A and 3B are diagrams illustrating a pair of coil pieces to be assembled to a stator core.
  • FIG. 2 is a schematic front view of one coil piece. 1 is a diagram showing the tip portions of the coil pieces joined together and their vicinity;
  • FIG. FIG. 2 is a diagram illustrating a schematic view of a welding target portion as viewed from the irradiation side.
  • 6 is a cross-sectional view taken along line AA in FIG. 5 through the area to be welded.
  • FIG. 1 is a diagram showing the relationship between the laser wavelength and the laser absorptance of various solid materials.
  • FIG. 4 is an explanatory diagram of a change in absorption rate during welding.
  • FIG. 13 is an image diagram of a keyhole etc. when a green laser is used.
  • FIG. 13 is an image diagram of a keyhole etc. when an infrared laser is used.
  • 4A to 4C are explanatory diagrams of the irradiation mode of a green laser according to the manufacturing method of this embodiment.
  • FIG. 2 is an explanatory diagram relating to scanning of a laser beam, and is an explanatory diagram of an emission center of a laser beam.
  • FIG. 2 is an explanatory diagram relating to laser beam scanning, and is an explanatory diagram of a movement mode of the laser beam.
  • FIG. 13 is an explanatory diagram of an irradiation mode in the case of an infrared laser according to a comparative example.
  • FIG. 4 is a cross-sectional view taken along the welding direction on the contact surface according to the present embodiment.
  • FIG. 11 is a cross-sectional view taken along the welding direction on the contact surface according to the comparative example.
  • 13 is an image of the bottom edge of the bonded surface according to the present embodiment. 13 is an image of the lower end of the joint surface according to the comparative example.
  • FIG. 13 is an explanatory diagram of robustness against deviation of the irradiation position in the radial direction.
  • FIG. 11 is a table showing multiple conditions (conditions 1 to 3) of the tests carried out.
  • FIG. 11 is a graph showing the relationship between the wobbling diameter and the number of sputters under different conditions.
  • FIG. 11 is a graph showing the relationship between the wobbling diameter and the bonding area and welding depth.
  • 1 is a diagram showing a preferred welding speed for each Y direction position (a change profile of the welding speed according to the Y direction position) with the horizontal axis representing the Y direction position along the Y direction and the vertical axis representing the welding speed.
  • 11 is an explanatory diagram of the wobbling pitch in the section from Y-direction position P1 to Y-direction position P2.
  • FIG. 13 is an explanatory diagram of the wobbling pitch in the section from Y direction position P3 to Y direction position P5.
  • FIG. 11 is an explanatory diagram of a first comparative example.
  • FIG. 11 is an explanatory diagram of a problem in the first comparative example.
  • FIG. 11 is an explanatory diagram of a second comparative example.
  • FIG. 13 is an explanatory diagram of a problem in the second comparative example.
  • 4 is a flowchart illustrating a manufacturing method of a motor stator.
  • FIG. 2 is a system configuration diagram of the manufacturing apparatus.
  • FIG. 1 is a cross-sectional view that shows a schematic cross-sectional structure of a motor 1 (an example of a rotating electric machine) according to one embodiment.
  • the rotating shaft 12 of the motor 1 is shown.
  • the axial direction refers to the direction in which the rotating shaft (center of rotation) 12 of the motor 1 extends
  • the radial direction refers to the radial direction centered on the rotating shaft 12. Therefore, the radially outer side refers to the side away from the rotating shaft 12, and the radially inner side refers to the side toward the rotating shaft 12. Additionally, the circumferential direction corresponds to the direction of rotation around the rotating shaft 12.
  • Motor 1 may be a motor for driving a vehicle, such as that used in a hybrid vehicle or an electric vehicle. However, motor 1 may also be used for any other purpose.
  • the motor 1 is an inner rotor type, with the stator 21 surrounding the radial outside of the rotor 30.
  • the radial outside of the stator 21 is fixed to the motor housing 10.
  • the rotor 30 is disposed radially inside the stator 21.
  • the rotor 30 includes a rotor core 32 and a rotor shaft 34.
  • the rotor core 32 is fixed to the radial outside of the rotor shaft 34 and rotates integrally with the rotor shaft 34.
  • the rotor shaft 34 is rotatably supported in the motor housing 10 via bearings 14a and 14b.
  • the rotor shaft 34 defines the rotating shaft 12 of the motor 1.
  • the rotor core 32 is formed, for example, from laminated steel plates of a circular magnetic material. Permanent magnets 321 are inserted into the magnet holes 320 of the rotor core 32. The number and arrangement of the permanent magnets 321 are optional. In a modified example, the rotor core 32 may be formed from a green compact in which magnetic powder is compressed and solidified.
  • End plates 35A, 35B are attached to both axial sides of rotor core 32.
  • end plates 35A, 35B may also have a function of adjusting imbalance of rotor 30 (a function of eliminating imbalance by cutting, etc.).
  • the rotor shaft 34 has a hollow portion 34A.
  • the hollow portion 34A extends over the entire axial length of the rotor shaft 34.
  • the hollow portion 34A may function as an oil passage.
  • oil is supplied to the hollow portion 34A from one axial end, and the oil flows along the radially inner surface of the rotor shaft 34, thereby cooling the rotor core 32 from the radially inner side.
  • the oil flowing along the radially inner surface of the rotor shaft 34 may be ejected radially outward through oil holes 341, 342 formed at both ends of the rotor shaft 34 (arrows R5, R6), and may be used to cool the coil ends 220A, 220B.
  • FIG. 1 shows a motor 1 with a specific structure
  • the structure of the motor 1 is arbitrary as long as it has a stator coil 24 (described below) joined by welding.
  • the rotor shaft 34 may not have a hollow portion 34A, or may have a hollow portion with an inner diameter significantly smaller than that of the hollow portion 34A.
  • FIG. 1 shows a specific cooling method
  • the cooling method of the motor 1 is arbitrary.
  • an oil introduction pipe inserted into the hollow portion 34A may be provided, or oil may be dripped from an oil passage in the motor housing 10 from the radial outside toward the coil ends 220A, 220B.
  • FIG. 1 shows an inner rotor type motor 1 in which the rotor 30 is disposed inside the stator 21
  • the present invention may be applied to other types of motors.
  • the present invention may be applied to an outer rotor type motor in which the rotor 30 is disposed concentrically outside the stator 21, or a dual rotor type motor in which the rotor 30 is disposed both outside and inside the stator 21.
  • Figure 2 is a plan view of the stator core 22 in a standalone state.
  • Figure 3 is a schematic diagram of a pair of coil pieces 52 assembled to the stator core 22.
  • Figure 3 shows the relationship between the pair of coil pieces 52 and the slots 220 with the radially inner side of the stator core 22 unfolded.
  • the stator core 22 is shown by a dotted line, and some of the slots 220 are not shown.
  • the stator 21 includes a stator core 22 and a stator coil 24 (see Figure 1).
  • the stator core 22 is made of, for example, a circular ring-shaped laminated steel plate of a magnetic material, but in a modified example, the stator core 22 may be formed of a green compact in which magnetic powder is compressed and solidified.
  • the stator core 22 may be formed of a split core that is split in the circumferential direction, or may not be split in the circumferential direction.
  • a plurality of slots 220 around which the stator coil 24 is wound are formed on the radially inner side of the stator core 22. Specifically, as shown in FIG.
  • the stator core 22 includes a circular back yoke 22A and a plurality of teeth 22B that extend radially inward from the back yoke 22A, and the slots 220 are formed between the plurality of teeth 22B in the circumferential direction.
  • the number of slots 220 is arbitrary, but in this embodiment, as an example, there are 48 slots 220.
  • the stator coil 24 includes a U-phase coil, a V-phase coil, and a W-phase coil (hereinafter, when U, V, and W are not distinguished, they will be referred to as "phase coils").
  • the base end of each phase coil is connected to an input terminal (not shown), and the end of each phase coil is connected to the end of the other phase coil to form the neutral point of the motor 1.
  • the stator coil 24 is star-connected.
  • the connection mode of the stator coil 24 may be changed as appropriate depending on the required motor characteristics, etc.
  • the stator coil 24 may be delta-connected instead of star-connected.
  • FIG. 4 is a schematic front view of one coil piece 52.
  • the coil pieces 52 are in the form of segment coils in which the phase coil is divided into units that are easy to assemble (for example, units that can be inserted into two slots 220).
  • the coil pieces 52 are formed by coating a linear conductor (rectangular wire) 60 with a rectangular cross section with an insulating coating 62.
  • the linear conductor 60 is formed from copper, as an example.
  • the linear conductor 60 may be formed from another conductive material such as iron.
  • the coil pieces 52 Before being assembled to the stator core 22, the coil pieces 52 may be formed into a generally U-shape having a pair of straight portions 50 and a connecting portion 54 connecting the pair of straight portions 50.
  • the pair of straight portions 50 When assembling the coil pieces 52 to the stator core 22, the pair of straight portions 50 are each inserted into a slot 220 (see FIG. 3).
  • the connecting portion 54 extends circumferentially so as to straddle a plurality of teeth 22B (and therefore a plurality of slots 220) at the other axial end side of the stator core 22, as shown in FIG. 3.
  • the number of slots 220 that the connecting portion 54 straddles is arbitrary, but is three in FIG. 3.
  • the straight portions 50 After being inserted into the slot 220, the straight portions 50 are bent circumferentially midway, as shown by the two-dot chain line in FIG. 4. As a result, the straight portion 50 becomes a leg portion 56 that extends axially within the slot 220, and a bridge portion 58 that extends circumferentially at one axial end of the stator core 22.
  • the pair of straight portions 50 are bent in a direction away from each other, but this is not limited thereto.
  • the pair of straight portions 50 may be bent in a direction toward each other.
  • the stator coil 24 may also have a neutral point coil piece for connecting the ends of the three phase coils to form a neutral point.
  • multiple legs 56 of the coil piece 52 shown in FIG. 4 are inserted side by side in the radial direction. Therefore, multiple circumferentially extending bridge portions 58 are lined up in the radial direction at one axial end of the stator core 22. As shown in FIG. 3, the bridge portion 58 of one coil piece 52 protruding from one slot 220 and extending to a first circumferential side (e.g., clockwise) is joined to the bridge portion 58 of another coil piece 52 protruding from another slot 220 and extending to a second circumferential side (e.g., counterclockwise).
  • a first circumferential side e.g., clockwise
  • a second circumferential side e.g., counterclockwise
  • first turn, second turn, and third turn are assembled in one slot 220.
  • first turn, second turn, and third turn starting from the radially outermost coil piece 52.
  • first turn coil piece 52 and the second turn coil piece 52 have their tip portions 40 joined together by a joining process described below
  • the third turn coil piece 52 and the fourth turn coil piece 52 have their tip portions 40 joined together by a joining process described below
  • fifth turn coil piece 52 and the sixth turn coil piece 52 have their tip portions 40 joined together by a joining process described below.
  • the coil pieces 52 are covered with an insulating coating 62, but the insulating coating 62 is removed only from the tip portion 40. This is to ensure electrical connection with the other coil pieces 52 at the tip portion 40.
  • FIG. 5 is a diagram showing the tip 40 of the coil pieces 52 joined together and its vicinity.
  • FIG. 5 also shows a schematic representation of the circumferential range D1 of the area 90 to be welded.
  • FIG. 6 is a schematic representation of the area 90 to be welded as viewed from the irradiation side.
  • FIG. 7 is a cross-sectional view taken along line A-A in FIG. 5, which passes through the area 90 to be welded.
  • FIG. 7 also shows a schematic representation of the range of the molten pool formed during welding, as indicated by the hatched area 1102.
  • FIG. 8 is a diagram showing the relationship between the laser wavelength and the laser absorptance of various individual materials.
  • the Z direction along the axial direction is defined.
  • the Z1 side in the Z direction i.e. the side irradiated with the laser beam
  • the Z2 side in the Z direction is referred to as the "lower side”.
  • the X direction along the radial direction and the X1 side and X2 side along the X direction are defined.
  • the structure relating to one coil piece 52 may be designated by adding the letter "A" after the reference numeral, such as tip portion 40A, and the structure relating to the other coil piece 52 may be designated by adding the letter "B" after the reference numeral, such as tip portion 40B.
  • the tip portions 40 may cross each other in an X-shape. In this case, each tip portion 40 may be cut so that no protruding portion is formed on the upper side of the X-shape.
  • the area to be welded 90 extends linearly along the abutment surface 401, as shown by range D1 in Fig. 6. That is, the area to be welded 90 extends linearly over range D1 in the Y direction with a width of range D2 in the X direction as shown in Fig. 7, as viewed from the side irradiated with the laser beam (see arrow W in Fig. 5).
  • the abutment surface 401 has a rectangular shape surrounded by axial outer end faces 42A, 42B and extension direction end faces 44A, 44B when viewed in the radial direction, but may have other shapes.
  • the welding target area 90 is set along the upper side (the exposed upper side of the four sides of the rectangle) formed by the axially outer end faces 42A, 42B of both tip portions 40 in the view (viewed radially) shown in FIG. 5.
  • the welding target area 90 extends horizontally, but in the view (viewed radially) shown in FIG. 5, it may extend in an upwardly convex C-shape or in other shapes depending on other shapes that the tip portion 40 can take.
  • the axially outer end faces 42A, 42B extend in the XY plane, but may be inclined relative to the XY plane.
  • welding is used as a joining method when joining the tip portions 40 of the coil pieces 52.
  • the welding method is not arc welding, such as TIG welding, but laser welding using a laser beam source as a heat source.
  • TIG welding By using laser welding instead of TIG welding, the axial length of the coil ends 220A, 220B can be reduced. That is, in the case of TIG welding, it is necessary to bend the tips of the coil pieces to be abutted axially outward and extend them in the axial direction, whereas in the case of laser welding, such bending is not necessary, and as shown in FIG. 5, welding can be achieved in a state in which the tip portions 40 of the coil pieces 52 to be abutted extend in the circumferential direction. This allows the axial length of the coil ends 220A, 220B to be reduced compared to when the tip portions 40 of the coil pieces 52 to be abutted are bent axially outward and extend in the axial direction.
  • a welding laser beam is applied to the welding target area 90 of the two abutted tip portions 40.
  • the irradiation direction (propagation direction) of the laser beam is approximately parallel to the axial direction, and is directed from the axial outside toward the axially outer end faces 42 (including the exposed sides of the abutment faces 401) of the two abutted tip portions 40.
  • Laser welding allows localized heating, so that only the tip portions 40 and their vicinity can be heated, effectively reducing damage (carbonization) of the insulating coating 62. As a result, multiple coil pieces 52 can be electrically connected while maintaining appropriate insulation performance.
  • FIG 8 is a diagram showing the relationship between the laser wavelength and the laser absorptance (hereinafter simply referred to as "absorption rate") for individual materials.
  • the horizontal axis represents the wavelength ⁇ and the vertical axis represents the absorptance, and the characteristics of individual materials, copper (Cu), aluminum (Al), silver (Ag), nickel (Ni), and iron (Fe), are shown.
  • the infrared laser most of the laser beam is reflected by the coil pieces 52 and not absorbed. For this reason, a relatively large amount of heat input is required to obtain the required joint area between the coil pieces 52 to be joined, which can cause significant thermal effects and unstable welding.
  • a green laser is used instead of an infrared laser.
  • the concept of a green laser includes not only a laser with a wavelength of 532 nm, i.e., an SHG (Second Harmonic Generation) laser, but also lasers with wavelengths close to 532 nm.
  • a laser with a wavelength of 0.6 ⁇ m or less that does not belong to the category of green lasers may be used.
  • the wavelength of a green laser can be obtained by converting the fundamental wavelength generated by, for example, a YAG laser or YVO4 laser through an oxide single crystal (for example, LBO: lithium triborate).
  • the absorption rate is high at about 50% for copper, which is the material of the linear conductor 60 of the coil piece 52. Therefore, according to this embodiment, it is possible to ensure the necessary joint area between the coil pieces 52 with a smaller amount of heat input compared to when an infrared laser is used.
  • Figure 9 is an explanatory diagram of how the absorption rate changes during welding.
  • the horizontal axis represents the laser power density and the vertical axis represents the laser absorption rate of copper, and the characteristics 100G for a green laser and 100R for an infrared laser are shown.
  • Figure 9 shows points P100 and P200 at which copper starts to melt for the green laser and the infrared laser, as well as point P300 at which a keyhole is formed.
  • the green laser can start melting copper at a lower laser power density than the infrared laser.
  • the difference between the absorptivity at point P300 at which a keyhole is formed and the absorptivity at the start of irradiation i.e., the absorptivity when the laser power density is 0
  • the change in absorptivity during welding is about 80%
  • the change in absorptivity during welding is about 40%, which is about half.
  • the change (drop) in absorption rate during welding is relatively large at approximately 80%, making the keyhole unstable and prone to variations in weld depth and width, and disturbance of the molten pool (e.g., spatter, etc.).
  • the change (drop) in absorption rate during welding is relatively small at approximately 40%, making the keyhole less likely to become unstable, and also less likely to cause variations in weld depth and width, and disturbance of the molten pool (e.g., spatter, etc.).
  • Spatter refers to metal particles that fly off when a laser or other device is irradiated.
  • FIG. 10B is an image diagram of a keyhole when an infrared laser is used, where 1100 indicates a weld bead, 1102 indicates a molten pool, and 1104 indicates a keyhole.
  • the arrow R1116 also shows a typical state of gas escape.
  • the arrow R110 also shows a typical state in which the irradiation position of the infrared laser is moved due to the small beam diameter.
  • FIG. 10A is an image of a keyhole when a green laser is used, and the meaning of the symbols is as described above with reference to FIG. 10B.
  • FIG. 10A it is easy to understand from FIG. 10A how the keyhole is stabilized and gas escape is improved due to the expansion of the beam diameter.
  • the movement trajectory (irradiation time) of the irradiation position required to obtain the required fusion width can be made relatively short (shortened) (described later).
  • FIG. 11 is an explanatory diagram of the irradiation mode of the green laser according to the manufacturing method of this embodiment.
  • FIG. 11A is an explanatory diagram of the scanning of the laser beam, and is an explanatory diagram of the emission center Ct0 of the laser beam.
  • FIG. 11B is an explanatory diagram of the scanning of the laser beam, and is an explanatory diagram of the movement mode of the laser beam.
  • FIG. 12 is an explanatory diagram of the irradiation mode in the case of an infrared laser according to a comparative example.
  • FIGS. 11 and 12 are schematic diagrams viewed in the laser irradiation direction, and the laser irradiation area (or the area to be irradiated) at the welding target part 90 at a certain point during welding is shown as a hatched area.
  • the circles 110 and 110' of the laser beam indicate the irradiation range at a certain point during welding, and the beam diameters ⁇ A and ⁇ A' are also shown.
  • the line Lref represents the abutment surface 401 (the upper side of the abutment surface 401).
  • the manufacturing method of this embodiment involves scanning the laser beam in a loop (see arrow R112) while moving it in the welding direction (travel direction).
  • the travel direction is along the upper edge of the contact surface 401 described above (i.e., a direction parallel to the upper edge), but may be slightly inclined relative to that edge due to errors, etc.
  • on the contact surface 401 refers to the portion that forms the upper edge of the contact surface 401 (see line Lref).
  • loop-shaped is a concept including any shape that can form a loop, such as a circle, an ellipse, and does not need to be completely closed, and may be a spirally continuous shape.
  • the loop shape is a shape in which circles are spirally continuous.
  • Such a loop shape can be realized, for example, by using a laser beam emitted (scanned) from the emission part in a manner that draws a circular trajectory a certain number of times per unit time.
  • FIG. 11A the circular trajectory (scanning) of the laser beam when the laser beam (emission part) is not moved is shown in the hatched region R11.
  • the emission center Ct0 of the laser beam is aligned with the abutment surface 401, thereby realizing a traveling direction along the upper side of the abutment surface 401.
  • the dashed dotted line TRct represents the trajectory (arrow indicates the traveling direction) of the center Ct1 of the laser beam when such a movement of the laser beam (linear movement along the upper side of the abutment surface 401) is performed.
  • the diameter of the circle associated with the loop (hereinafter also referred to as the "wobbling diameter ⁇ B") is arbitrary, but a preferred range will be described later.
  • the wobbling diameter ⁇ B may be larger than the beam diameter ⁇ A of the laser beam.
  • the amount of movement in the direction of travel per one loop scan (hereinafter also referred to as "wobbling pitch pt") is equal to or less than the beam diameter ⁇ A of the laser beam.
  • “per one loop scan” refers to one revolution from one phase of the circle to the same phase. This allows the irradiation range for one loop and the irradiation range for the next loop to be set continuously along the welding direction on the contact surface 401, as shown in FIG. 11. For example, if the wobbling pitch pt is 1/2 the beam diameter ⁇ A of the laser beam, the irradiation range for one loop and the irradiation range for the next loop will overlap by 1/2 the beam diameter ⁇ A on the contact surface 401.
  • the molten pool formed in the area to be welded 90 can be moved in the welding direction on the contact surface 401 while maintaining the molten pool.
  • the molten pool can be moved in the welding direction on the contact surface 401 by the wobbling pitch pt for each loop while maintaining the molten pool.
  • the wobbling pitch pt is constant for one welding target portion 90, but may be variable.
  • the size of the beam diameter ⁇ A may be the size at the emission end.
  • the beam diameter ⁇ A represents a Gaussian beam diameter (1/e 2 ), but in the case of an elliptical beam, the length of the major axis or minor axis of the elliptical spot may be substituted.
  • the beam diameter ⁇ A is preferably ⁇ 0.1 mm or more, and more preferably ⁇ 0.15 mm or more.
  • the wobbling pitch pt can also be increased under the condition that the laser beam has a beam diameter ⁇ A or less.
  • the laser beam is continuously irradiated with a laser output of 3.0 kW or more for multiple loop scans.
  • the laser beam may be continuously irradiated to the entire area 90 to be welded. This makes it easier to maintain the molten pool and shortens the welding time, although the output may be lower than with irradiation using pulsed oscillation.
  • the beam diameter ⁇ A' is relatively small, for example ⁇ 0.08 mm, due to the use of an infrared laser as described above.
  • the wobbling pitch pt' is 0.1 mm.
  • the irradiation range for each loop is discontinuous along the welding direction on the contact surface 401.
  • FIG. 13 is a cross-sectional view taken along line B-B in FIG. 11 for this embodiment (cross-sectional view taken along the welding direction on the abutment surface 401), and FIG. 14 is a cross-sectional view taken along line C-C in FIG. 12 for the comparative example.
  • the joint surface is shown as a schematic diagram by hatched areas SC13 and SC14.
  • the joint surface refers to the surface of the abutment surface 401 that is joined due to welding.
  • FIG. 15 and FIG. 16 show images of a part of the joint surface (the lower end of the joint surface) when cut at the abutment surface 401, FIG.
  • FIG. 15 shows an image according to this embodiment
  • FIG. 16 shows an image according to the comparative example.
  • the irradiation ranges for each loop are discontinuous along the welding direction on the abutting surface 401, so the height H1' of the lower end of the joint surface (welding depth H1') varies greatly along the welding direction, as shown in Figures 14 and 16. That is, between the irradiation ranges for each loop, there are areas where the height H1' suddenly becomes small (the welding depth suddenly becomes shallow). As a result, there is an inconvenience that the joint area (the area of the joint surface) tends to become insufficient. To address this, it is possible to further reduce the wobbling pitch pt' so that the irradiation ranges for each loop overlap, but such a measure is likely to cause other inconveniences, such as excessive welding time or excessive heat input.
  • the irradiation ranges of each loop are continuous along the welding direction on the contact surface 401.
  • the beam diameter ⁇ A is relatively large, even if the wobbling pitch pt is increased, the irradiation ranges of each loop can be continuous, and the welding time and heat input can be reduced (efficient).
  • the wobbling pitch pt may be 1/4 or more of the beam diameter ⁇ A of the laser beam under conditions of the beam diameter ⁇ A or less, more preferably 1/3 or more of the beam diameter ⁇ A, and most preferably 1/2 or more.
  • FIG. 17 is an explanatory diagram of robustness against deviations in the radial irradiation position.
  • the horizontal axis represents the laser radial deviation amount
  • the vertical axis represents the bonding area
  • characteristic curves 1701, 1702, and 1703 for three different methods are shown.
  • the laser radial deviation amount represents the radial position of the center of the irradiation area when the abutment surface 401 is set to "0”
  • negative values represent the radial inward position.
  • Characteristic curve 1701 shows the case of this embodiment
  • characteristic curve 1702 shows the case of the first comparative example
  • characteristic curve 1703 shows the case of the second comparative example.
  • the second comparative example uses a green laser, but the scanning method is linear scanning, unlike this embodiment. That is, in the second comparative example, the green laser scans linearly along the welding direction on the abutment surface 401.
  • the present embodiment and the first comparative example have relatively high robustness against deviation of the irradiation position in the radial direction, and even if the irradiation position is shifted 0.2 mm inward or outward in the radial direction, the bonding area does not fall to 3 mm2 or less. In the case of the present embodiment, it can be seen that in the region where the irradiation position is shifted 0.4 mm or more inward or outward in the radial direction, the robustness is higher than that of the first comparative example.
  • FIG. 18 is a table showing the multiple conditions (conditions 1 to 3) under which the test was conducted.
  • FIG. 19 is a graph showing the relationship between the wobbling diameter ⁇ B and the number of spatters for each condition
  • FIG. 20 is a graph showing the relationship between the wobbling diameter ⁇ B and the joint area and the weld depth.
  • graph 201 relates to the weld area
  • graph 202 relates to the weld depth.
  • plot p1 relates to condition 1
  • plot p2 relates to condition 2
  • plot p3 relates to condition 3.
  • the laser scanning speed is adjusted so that the heat input is the same under conditions 1 to 3.
  • the laser scanning speed corresponds to the length of the laser beam irradiation path per unit time (the length along the loop-shaped path).
  • the welding speed is the movement distance of the laser beam irradiation position per unit time, and is a value obtained by, for example, dividing the movement distance of the laser beam irradiation position over a certain time period (the movement distance along the welding direction on the contact surface 401) by the same time period.
  • the conditions common to each condition (fixed conditions) are that a green laser is used, that the beam diameter ⁇ A is 0.273 mm, and that the output distribution density is a Gaussian distribution.
  • a larger wobbling diameter ⁇ B is advantageous from the viewpoint of reducing the number of spatters, but a smaller wobbling diameter ⁇ B is advantageous from the viewpoint of increasing the welding depth and the joining area. Therefore, taking these trade-offs into consideration, a preferred range of the wobbling diameter ⁇ B may be adapted. For example, when the wobbling diameter ⁇ B is less than ⁇ 0.4, the number of spatters may increase sharply as the wobbling diameter ⁇ B decreases, so the wobbling diameter ⁇ B may preferably be ⁇ 0.4 mm or more.
  • the wobbling diameter ⁇ B exceeds ⁇ 0.75 mm, the joining area becomes relatively small, so the wobbling diameter ⁇ B may preferably be ⁇ 0.75 mm or less.
  • the wobbling diameter ⁇ B is between 1.46 and 2.74 times the beam diameter ⁇ A of the laser beam. Therefore, the wobbling diameter ⁇ B may be adapted to be between 1.4 and 2.8 times the beam diameter ⁇ A of the laser beam.
  • FIG. 21 is a diagram showing a preferred welding speed for each Y-direction position (a profile of changes in the welding speed according to the Y-direction position), with the horizontal axis representing the Y-direction position along the Y-direction and the vertical axis representing the welding speed.
  • the positive side of the horizontal axis corresponds to the Y2 side described above, and in this example, the Y1 side of the welding target portion 90 (see FIG. 6) is set as the welding start position, and the laser beam emission center Ct0 (see FIG. 11A) is moved from the Y1 side to the Y2 side during welding.
  • FIG. 11A the profile of changes in the welding speed
  • each Y-direction position (a profile of changes in the laser output according to the Y-direction position) in the form of a waveform R21.
  • the Y-direction position P1 indicates the irradiation start position
  • the Y-direction position P5 indicates the irradiation end position.
  • the section from the Y-direction position P1 to the Y-direction position P5 corresponds to the range D1 described above with reference to FIG. 5 and FIG. 6.
  • the welding speed is lowest at the start of irradiation and is increased thereafter.
  • the welding speed V1 in the section from Y-direction position P1 to Y-direction position P2
  • the welding speed V2 in the section from Y-direction position P2 to Y-direction position P3
  • the welding speed V3 in the section from Y-direction position P3 to Y-direction position P5.
  • Welding speed V1 is preferably significantly smaller than 80 mm/s, for example in the range of 5-35 mm/s, and may be approximately 20 mm/s.
  • Welding speed V3 is preferably 80 mm/s or greater, for example approximately 100 mm/s.
  • the section from Y-direction position P1 to Y-direction position P2 is preferably shorter than the section from Y-direction position P3 to Y-direction position P5, and more preferably shorter than the section from Y-direction position P3 to Y-direction position P4.
  • the section from Y-direction position P1 to Y-direction position P2 is preferably less than 20% of range D1, and preferably 10% or less.
  • the section from Y-direction position P2 to Y-direction position P3 may be shorter than the section from Y-direction position P1 to Y-direction position P2.
  • the laser output is preferably highest in the section from Y-direction position P3 to Y-direction position P4.
  • the laser output may gradually increase from Y-direction position P1 and be maintained at a constant value in the section from Y-direction position P3 to Y-direction position P4.
  • the laser output may then be reduced toward 0 (output off) using the section from Y-direction position P4 to Y-direction position P5.
  • the laser output is maximized in the section from Y-direction position P3 to Y-direction position P4 within the section of welding speed V3, and the main portion of the welding target area 90 can be welded with high quality in a short time.
  • FIG. 22 is an explanatory diagram of the wobbling pitch pt (wobbling pitch pt at welding speed V1) (an example of the "first movement amount") in the section from Y-direction position P1 to Y-direction position P2, and
  • FIG. 23 is an explanatory diagram of the wobbling pitch pt (wobbling pitch pt at welding speed V3) (an example of the "second movement amount") in the section from Y-direction position P3 to Y-direction position P5.
  • the distance in the Y direction between these two circles 110 corresponds to the wobbling pitch pt.
  • the laser scanning speed is constant over the entire section from the Y direction position P1 to the Y direction position P5.
  • the wobbling pitch pt increases accordingly.
  • the lap ratio (area of overlapping part/area of circle x 100) of the two circles 110 decreases accordingly.
  • the welding speed V3 may be set so that the lap ratio (area of overlapping part/area of circle x 100) of the two circles 110 is preferably 15% or more and 20% or less.
  • FIGS. 24A and 24B are explanatory diagrams of the first comparative example, and 24B is an explanatory diagram of the problem associated with the first comparative example.
  • 25A and 25B are explanatory diagrams of the second comparative example, and 25B is an explanatory diagram of the problem associated with the second comparative example.
  • Both Figs. 24A and 25A are diagrams showing preferred welding speeds for each Y direction position (profile of changes in welding speed according to Y direction position) with the horizontal axis representing Y direction position along the Y direction and the vertical axis representing welding speed, similar to Fig. 21 described above for this embodiment.
  • Both Figs. 24B and 25B are diagrams showing schematic views of the welding target location 90' or 90" as viewed from the irradiation side, similar to Fig. 6 described above for this embodiment.
  • the laser beam moves in the Y direction at a relatively high speed before the molten pool becomes large enough at the welding start position (Y direction position P1), making it easier for the laser beam to irradiate the outside of the molten pool.
  • the laser beam moves from the Y1 side to the Y2 side, the laser beam is easier to irradiate the outside of the molten pool on the Y2 side.
  • defects are more likely to occur at the welding start position (Y direction position P1).
  • the material (solid) of the irradiated area at the tip 40 of the coil piece 52 is blown away, making it easier for a cavity (represented by the unhatched area in FIG. 24B) to occur.
  • a relatively small welding speed V1 is used in the section from Y-direction position P1 to Y-direction position P2. This makes it difficult for the laser beam to be irradiated to the outside of the molten pool before the molten pool becomes sufficiently large. As a result, the inconveniences that occur in the first comparative example can be reduced.
  • the length of the section from Y-direction position P1 to Y-direction position P2 is preferably set so that in this section, the circle 110 is formed two or more times at the corresponding wobbling pitch pt (see FIG. 23), and more preferably, is set so that in this section, the circle 110 is formed 7 to 13 times at the corresponding wobbling pitch pt.
  • the fusion width w2 (see the radial range D2 of the welding target portion 90 shown in FIG. 7) is likely to be larger than the desired value, as shown in FIG. 25B.
  • the fusion width w2 becomes larger as it moves toward the Y2 side (the same applies to the welding depth H1 shown in FIG. 13).
  • a relatively slow welding speed V1 is used in the section from Y-direction position P1 to Y-direction position P2, but a higher welding speed (particularly welding speed V3) is used in the subsequent section.
  • a higher welding speed particularly welding speed V3
  • the welding time (time required for welding) per welding area 90 can be made relatively short. In other words, the inconveniences that arise in the second comparative example can be reduced.
  • welding speed V1, V2, and V3 are used, but welding speed V1 or welding speed V3 may be used instead of welding speed V2. Alternatively, four or more types of welding speeds may be used.
  • FIG. 26 is a flow chart showing the outline of the manufacturing method for the stator 21 of the motor 1.
  • FIG. 27 is a system configuration diagram of the manufacturing device 300.
  • this manufacturing method includes an assembly process (step S150) in which the coil pieces 52 are attached to the stator core 22.
  • this manufacturing method includes a joining process (step S152) in which the tip ends 40 of the coil pieces 52 are joined together by laser welding. The method of joining the tip ends 40 of the coil pieces 52 together by laser welding is as described above.
  • the joining process includes a setting process (step S1521) in which the tip portions 40 of each pair of coil pieces 52 are set so as to abut against each other in the radial direction, as described above.
  • the setting process the state in which the tip portions 40 of each pair of coil pieces 52 are abutted against each other in the radial direction may be maintained using a jig 302.
  • the joining process includes an irradiation process (step S1522) in which, after the setting process, a laser beam is irradiated from the irradiation device 304 to the welding target points 90 as described above.
  • the manner of irradiation of the laser beam from the irradiation device 304 is as described above, and may be controlled by the control device 301.
  • the setting process and the irradiation process may be performed as a set for one or more predetermined number of welding target points 90, or may be performed collectively for all welding target points 90 related to one stator 21.
  • the present manufacturing method may end by completing the stator 21 by appropriately performing various necessary processes after the joining process.

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Plasma & Fusion (AREA)
  • Mechanical Engineering (AREA)
  • Manufacturing & Machinery (AREA)
  • Power Engineering (AREA)
  • Manufacture Of Motors, Generators (AREA)
  • Laser Beam Processing (AREA)

Abstract

Est divulgué un procédé de fabrication de stator de machine électrique rotative comprenant : une étape pour amener en contact les parties d'extrémité d'un premier composant bobine et d'un autre composant bobine servant à former une bobine de stator d'une machine électrique rotative ; et une étape d'irradiation consistant à diriger un faisceau laser ayant une longueur d'onde de 0,6 µm maximum vers un côté, sur le côté dénudé de la surface de contact des parties d'extrémité. L'étape d'irradiation comprend le balayage en boucle du faisceau laser simultanément à l'avancement du faisceau laser dans le sens de déplacement, lequel inclut une composante de direction le long de laquelle s'étend ledit un côté, la quantité de mouvement dans le sens de déplacement par boucle de balayage étant inférieure ou égale au diamètre du faisceau laser.
PCT/JP2023/034370 2022-10-11 2023-09-21 Procédé de fabrication de stator de machine électrique rotative et dispositif de fabrication de stator de machine électrique rotative Ceased WO2024080097A1 (fr)

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CN202380071356.1A CN120077557A (zh) 2022-10-11 2023-09-21 旋转电机用定子制造方法以及旋转电机用定子制造装置
DE112023003425.7T DE112023003425T5 (de) 2022-10-11 2023-09-21 Verfahren zum herstellen eines stators für eine drehende elektrische maschine und vorrichtung zum herstellen eines stators für eine drehende elektrische maschine
JP2024551360A JPWO2024080097A1 (fr) 2022-10-11 2023-09-21

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN119794576A (zh) * 2025-02-25 2025-04-11 大连理工大学 一种同轴复合激光焊接方法及扁线电机绕组的焊接方法

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2018020340A (ja) * 2016-08-02 2018-02-08 トヨタ自動車株式会社 平角線のレーザ溶接方法
JP2021044883A (ja) * 2019-09-09 2021-03-18 トヨタ自動車株式会社 導線の接合方法

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2018020340A (ja) * 2016-08-02 2018-02-08 トヨタ自動車株式会社 平角線のレーザ溶接方法
JP2021044883A (ja) * 2019-09-09 2021-03-18 トヨタ自動車株式会社 導線の接合方法

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN119794576A (zh) * 2025-02-25 2025-04-11 大连理工大学 一种同轴复合激光焊接方法及扁线电机绕组的焊接方法

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