Stator Electric Wire Segmentation for Friction Reduction
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Solution Overview
Problem
Conventional stator manufacturing methods for electric rotating machines face challenges such as damaged insulating coats due to friction, require long electric wires, and result in low productivity and high costs due to the need for large-scale machinery and complex handling.
Innovation Solution
The stator design features electric wires with offset in-slot portions and turn portions, including bulges and shoulder parts, which are plastically deformed and assembled to minimize friction and facilitate easier handling, using a method that ensures precise alignment and efficient assembly without damaging insulating coats.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the planar electric wire assembly is rolled into a hollow cylindrical shape to form the stator coil, then the space factor of the electric wires in the slots is improved, but the insulating coats of the in-slot portions may be damaged due to friction between the corresponding in-slot portions
Solution Approach 1:
The electric wire is divided into multiple in-slot portions and turn portions, with each in-slot portion being independently positioned in a slot. The corresponding in-slot portions are arranged at different radial positions rather than being densely stacked, which segments the friction contact points and prevents continuous friction damage to the insulating coats during the rolling process.
Solution Approach 2:
The arrangement of in-slot portions transitions from a two-dimensional dense stacking in the radial direction to a three-dimensional distribution involving circumferential and axial positions. By positioning corresponding in-slot portions at different radial positions and distributing them across multiple slots circumferentially, the friction contact is distributed in multiple dimensions, reducing the concentration of friction stress on the insulating coats.
2Ease of manufacture
If each electric wire is configured with a long length to achieve the required winding pattern, then the stator coil can be formed with proper turn portions connecting in-slot portions, but a large scale shaping machine is needed and handling during manufacture becomes difficult
Solution Approach 1:
The electric wire is segmented into multiple in-slot portions (first to nth portions) that are sequentially received in p slots, with turn portions connecting adjacent in-slot portions. This segmentation allows the wire to be arranged in a compact pattern that reduces the overall wire length required while maintaining the necessary winding configuration for proper magnetic field generation.
Solution Approach 2:
Multiple in-slot portions are combined into a single continuous electric wire rather than using separate wires for each slot. This merging approach allows the wire to be formed in one continuous shaping process, eliminating the need for multiple separate wiring operations and reducing the overall complexity of the manufacturing process despite the reduced wire length.
3Quantity of substance
If the corresponding in-slot portions are densely arranged to improve space factor, then more wire can be packed in the slots, but friction between the portions increases causing insulating coat damage
Solution Approach 1:
The dense arrangement of in-slot portions is segmented by positioning corresponding in-slot portions at different radial positions. Instead of having all in-slot portions stacked closely in the radial direction, they are distributed across different radial levels, which segments the friction contact paths and reduces the intensity of friction between corresponding portions during the rolling process.
Solution Approach 2:
The turn portions act as intermediaries that connect the in-slot portions at different radial positions. By routing the wire through turn portions located outside the slots, the design creates buffer zones that reduce direct friction contact between corresponding in-slot portions, thereby protecting the insulating coats while maintaining high wire density in the slots.
Data Source
AI summary
A stator includes a hollow cylindrical stator core and a stator coil comprised of electric wires. Each of the electric wires has n in-slot portions and (n−1) turn portions, where n≧4. The in-slot portions are sequentially received in p slots of the stator core, where p≧n. The turn portions are located outside the slots to connect adjacent pairs of the in-slot portions. The radial distances from the longitudinal axis of the stator core to the first to the nth in-slot portions successively decrease. Each of the electric wires further includes bulges. Each of the bulges is formed, on a surface of a corresponding one of the in-slot portions or a surface of a portion of the electric wire which falls on an imaginary line extending axially from the corresponding in-slot portion, so as to protrude from the corresponding in-slot portion in a radial direction.