Hairpin Stator Twisting With Concave Ends for Compact Windings
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Solution Overview
Problem
Existing methods for manufacturing stators for electric motors in motor vehicles result in either excessive space usage due to protruding end sections or significant material waste, particularly in hairpin stators with plug-in windings.
Innovation Solution
A method involving a stator body with concave end contours on hairpin ends that allows for twisting and coupling without additional radial support, using a twisting tool that engages these contours for direct force transmission, eliminating the need for additional space and material waste.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the end sections of hairpin ends are made longer to allow for twisting and welding operations, then the ease of manufacture is improved, but the volume of the stator increases
Solution Approach 1:
The invention introduces a radial dimension for force application by using a twisting tool that applies force in the radial direction of the stator body. This allows the hairpin ends to be twisted effectively without requiring excessive axial length, as the force is applied from a different spatial dimension (radial rather than axial).
Solution Approach 2:
The hairpin ends are preliminarily positioned and held in place before the twisting operation. The holding tool secures the hairpin ends in the correct position, allowing the twisting tool to then apply radial force to twist them into the final configuration without requiring additional axial space.
2Manufacturing precision
If a holding tool is used to secure hairpin ends during twisting, then the manufacturing precision is improved, but the device complexity increases
Solution Approach 1:
The holding tool and twisting tool are combined into a single integrated device. The holding tool secures the hairpin ends while the twisting tool applies radial force to twist them, both functions being performed by one tool rather than requiring separate tools for holding and twisting operations.
Solution Approach 2:
The twisting tool is designed with multi-functionality, serving both as a holding tool to secure the hairpin ends and as a twisting tool to apply the necessary radial force. This universal tool eliminates the need for separate specialized tools for each function.
Data Source
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AI summary
A manufacturing method for a stator (1) for an electric machine suitable for powering a motor vehicle, comprising: - providing a stator body (4) with a plurality of stator slots (5), - arranging hairpins (6) in the stator slots (5), wherein a hairpin end face of each hairpin (6) has a concave end contour (10) extending towards the end face of each hairpin end (7) projecting from a stator slot (5), and - twisting the hairpin ends (7) in a circumferential direction (U) of the stator body (4) by engaging a twisting tool in the concave end contours (10) and exerting a twisting force on the hairpin ends (7) by the twisting tool in the circumferential direction (U). Also, an electric machine comprising such a stator for powering a motor vehicle. A motor vehicle with an electric drive system comprising an electric machine with such a stator.