Stator Coil End Welding Using Short-Wavelength X-Joint Laser Joining
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Solution Overview
Problem
The existing methods for manufacturing stators in rotating electrical machines are costly due to the need for complex machining of coil piece ends to achieve smooth laser beam radiation, which increases the machining cost.
Innovation Solution
A method involving the installation of coil pieces with a rectangular cross-section in a stator core and joining their ends using laser welding, where the ends are brought into contact in an X-shape and a laser beam with a wavelength of 0.6 μm or less is applied to the C-shaped side of the contact surface, melting both the contact and non-contact surfaces for effective joining.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If coil piece ends are machined into C-shape with arc-shaped surfaces, then smooth laser beam radiation is achieved, but machining cost increases
Solution Approach 1:
Instead of machining the coil piece ends into C-shape to achieve smooth laser radiation, the patent inverts the approach by using a rectangular cross-section coil piece with a laser wavelength of 0.6 μm or less that can directly radiate onto the rectangular end surface without requiring complex arc-shaped machining. This eliminates the need for costly C-shape machining while achieving effective laser radiation.
Solution Approach 2:
The patent changes the laser wavelength parameter to 0.6 μm or less, which enables the laser beam to effectively radiate onto the rectangular end surface of the coil piece without requiring the surface to be machined into a C-shape. This parameter change resolves the contradiction by making the laser radiation effective on simpler geometries.
2Ease of manufacture
If coil piece ends are joined by laser welding with simple rectangular cross-section, then machining cost is reduced, but joining reliability may be compromised
Solution Approach 1:
The patent uses a laser wavelength of 0.6 μm or less, which provides superior absorption characteristics on rectangular coil piece ends compared to conventional longer wavelengths. This parameter change ensures reliable welding of rectangular cross-section coil pieces without requiring costly C-shape machining, thus maintaining joining reliability while reducing manufacturing cost.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach allows for the proper joining of coil pieces at a relatively low machining cost, reducing the axial length of the coil ends and improving the reliability of the welded portion while maintaining insulation performance.
Implementation Method 1
a radiation step of applying a laser beam with a wavelength of 0.6 μm or less in an axial direction toward a C-shaped side, as viewed in the radial direction, of a contact surface between the ends after the setting step
Implementation Method 2
Part of the C-shaped side and part of an axially outer non-contact surface that is continuous with the contact surface between the ends are melted in the radiation step
Implementation Method 3
applying a laser beam with a wavelength of 0.6 μm or less... toward a C-shaped side... of a contact surface
Data Source
AI summary
A method for manufacturing a stator for a rotating electrical machine includes: installation step of installing coil pieces with rectangular cross section for stator coil in stator core; and joining step of joining ends of coil pieces by laser welding after installation step. The joining step includes a setting step of bringing the ends into contact with each other in radial direction that the ends cross over each other in an X-shape as viewed in the radial direction, and a radiation step of applying a laser beam with a wavelength of 0.6 μm or less in an axial direction toward a C-shaped side, as viewed in the radial direction, of a contact surface between the ends after the setting step. Part of the C-shaped side and part of an axially outer non-contact surface that is continuous with the contact surface between the ends are melted in the radiation step.