Stator Busbar Thickness Layout for Laser Weld Insulation Protection
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Solution Overview
Problem
In rotating electric machines, the insulating coat on coil end portions is often damaged during laser welding due to laser beam penetration, particularly when connecting busbars to stator windings, leading to inefficiencies in the welding process.
Innovation Solution
The busbar is designed with protruding portions that have a greater thickness in the direction of the laser beam than the main body portion, and these portions are shaped to minimize laser beam penetration and heat capacity, allowing for precise laser welding without damaging the insulating coat.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the busbar main body portion thickness is increased to prevent laser beam penetration, then the insulating coat damage is prevented, but the heat capacity increases and weldability deteriorates
Solution Approach 1:
The busbar is designed with non-uniform thickness: the connection portion has greater thickness than the main body portion. This local quality change allows the connection portion to stop the laser beam and protect the insulating coat, while the thinner main body portion maintains low heat capacity for good weldability. The thickness difference creates different functional zones within the same component.
Solution Approach 2:
The busbar is segmented into two functional zones with different thicknesses: the connection portion (thicker) for laser welding and insulating coat protection, and the main body portion (thinner) for low heat capacity and good weldability. This segmentation allows each zone to optimize its function independently.
2Reliability
If the protruding portion thickness is increased to suppress laser beam penetration, then the insulating coat damage is prevented, but the heat capacity at the connection portion increases
Solution Approach 1:
The protruding portion has locally increased thickness compared to the main body portion, creating a thickness gradient. This local quality enhancement at the connection point provides sufficient material to stop the laser beam without requiring the entire busbar to be thick, thus controlling heat capacity while preventing insulating coat damage.
3Ease of manufacture
If the busbar is formed by punching a flat plate with uniform thickness, then the manufacturing is simple, but the laser beam penetrates the welded portion and damages the insulating coat
Solution Approach 1:
The busbar transitions from uniform thickness to non-uniform thickness, with the connection portion having greater thickness than the main body portion. This local quality modification addresses the laser penetration issue at the critical connection area while maintaining relative manufacturing simplicity through processes like selective machining or forming.
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 configuration enables effective laser welding of busbars to stator windings while preventing damage to the insulating coat, maintaining weldability and reducing energy requirements.
Implementation Method 1
The protruding portions and the coil end portion are joined by laser welding. When the protruding portions of the busbar are extended radially from the main body portion and are connected by laser welding to the coil end portions
Implementation Method 2
since the thickness of the protruding portion of the busbar in the direction in which a laser beam is emitted during laser welding is made greater than a plate thickness of the main body portion, it is possible to suppress the laser beam from penetrating the welded portion during the laser welding
Data Source
AI summary
A stator includes a stator core, stator windings provided in the stator core, and a busbar connected to coil end portions of the stator windings. The busbar is composed of a flat conductor body and has a main body portion extended in a circumferential direction in parallel to a circumference of the stator core and multiple protruding portions extended radially from the main body portion. The protruding portions and the coil end portions are joined by laser welding. A thickness of each of the protruding portions in a laser beam emitting direction in which a welded portion is irradiated with a laser beam during the laser welding is greater than a plate thickness of the main body portion in the same direction.