Rectangular Wave Coil Manufacturing for Electric Rotary Machines
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Solution Overview
Problem
Existing methods for producing coils for electric rotary machines result in undesirable deformation and increased height of coil ends due to folding and physical interference between adjacent segments, limiting the minimization of coil end height.
Innovation Solution
A method involving bending straight coil wires into rectangular wave shapes, twisting and weaving them to form a wire bundle, and folding at coil bend-forming portions to eliminate 180° twisting, allowing for stepwise coil end formation without deformation, thereby reducing coil end height and preventing physical interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the coil is made of a single wire and folded to mount in the stator core, then the number of joints is reduced, but the wire undergoes undesirable deformation and it becomes difficult to shape coil ends stepwise due to physical interference between adjacent segments
Solution Approach 1:
The coil is divided into multiple straight coil wires that are bundled together, with each wire being processed separately through bending and twisting operations before final assembly. This segmentation allows each wire to be shaped precisely without deformation while maintaining structural integrity through the bundle configuration.
Solution Approach 2:
The coil structure transitions from a two-dimensional folded wire configuration to a three-dimensional bundled arrangement where multiple straight wires are positioned in parallel. This dimensional change eliminates the need for folding operations that cause deformation while achieving the same electrical winding function through spatial arrangement.
2Ease of operation
If segment conductors are twisted at the center to insert legs into slots, then the coil ends protrude from the stator core, but this increases the height of coil ends which is undesirable
Solution Approach 1:
Instead of twisting the coil center outward to achieve slot insertion, the invention inverts the approach by bending straight wires into rectangular wave shapes where the bends themselves form the coil ends that insert into slots. This reversal of the traditional twisting method eliminates protrusion while maintaining ease of slot insertion.
Solution Approach 2:
The straight coil wires are bent into curved rectangular wave shapes with controlled bend radii, creating smooth transitions that facilitate slot insertion without the need for sharp twists. The curvature is optimized to achieve both ease of insertion and minimal coil end height projection.
3Length of stationary object
If the bend of segment conductors is shaped in the form of a crank without twisting, then coil end height is minimized, but the ability to decrease coil end height further is limited by the constant slot interval and uniform conductor thickness
Solution Approach 1:
Different sections of the coil wires are given different properties: straight sections maintain uniform thickness for structural consistency, while bend sections are locally shaped into rectangular wave forms with optimized radii. This local differentiation allows precise control of coil end height in specific regions without compromising the overall coil structure.
Solution Approach 2:
The invention changes the geometric parameters of the coil wires by bending them into rectangular wave shapes with variable bend radii and angles. This parameter optimization allows further reduction of coil end height beyond the crank shape limitation, adapting the coil geometry to achieve minimal projection while maintaining electrical performance.
Data Source
AI summary
A method of producing a coil which comprises steps of bending each of straight coil wires into a rectangular wave shape including in-slot portions to be disposed in slots of a stator core and turned portions connecting between the in-slot portions, turning a coil bend-forming portion that is one of the in-slot portions of each coil wire which becomes a folded bend of a phase winding by 180° around an axis thereof, twisting the turned portions of the coil wires together to weave the coil wires into a wire bundle, and folding the wire bundle at the coil bend-forming portions of the coil wires to place sides of the wire bundle to overlap each other to make the coil, thereby eliminating the 180° twisting of the coil bend-forming portions to produce the coil without any undesirable deformation of the phase windings.