Stator Winding Method for Permanent Magnet Motors
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Solution Overview
Problem
The existing stator winding methods for permanent magnet motors increase the cross-sectional area of slots, leading to reduced magnetic-path widths and efficiency due to gaps between conductive wires, and complicate the bobbin machine mechanism, making it difficult to achieve continuous winding and proper wire arrangement.
Innovation Solution
A stator winding method that reduces the cross-sectional area of slots by varying the depths of slot portions and winding diameters, allowing for increased magnetic-path widths without increasing the stator core's outer diameter, using a bobbin machine with three nozzles arranged at 120 degrees to wind conductive wires around teeth in alternating processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the gap between conductive wires wound around adjacent teeth is increased to allow nozzle movement, then the winding process can be completed, but the cross-sectional area of each slot increases, narrowing the magnetic path and increasing excitation loss, which reduces motor efficiency
Solution Approach 1:
The winding process is divided into two separate processes: first winding conductive wires around every other tooth (odd-numbered teeth), then winding around the remaining teeth (even-numbered teeth). This segmentation allows the nozzle to access each tooth without requiring large gaps between adjacent wires, as wires are wound alternately rather than continuously around all teeth in sequence.
Solution Approach 2:
The conductive wires are wound around odd-numbered teeth first, establishing a preliminary winding pattern. Then the nozzle proceeds to wind around even-numbered teeth, fitting wires into the spaces created by the first winding pass. This preliminary action allows the nozzle to operate with smaller clearance while still completing the winding process.
2Productivity
If a bobbin machine with the same number of nozzles as slots is used to wind all teeth simultaneously, then winding efficiency increases, but the mechanism becomes complicated with increased number of wire bobbins and swinging mechanisms
Solution Approach 1:
Instead of using multiple nozzles to wind all teeth simultaneously, the patent segments the winding task into two sequential processes using a single nozzle: first winding odd-numbered teeth, then even-numbered teeth. This reduces the number of nozzles and wire bobbins required, simplifying the machine mechanism while maintaining productivity through optimized process sequencing.
3Ease of operation
If the swinging stroke of the bobbin machine is increased to arrange wires properly on the inner circumferential side, then wire arrangement improves, but the inner diameter of the stator increases, reducing magnetic-path widths and deteriorating motor efficiency
Solution Approach 1:
The conductive wires are first wound around odd-numbered teeth, creating a preliminary structure that guides subsequent wire placement. When winding even-numbered teeth, the nozzle can guide wires into the spaces between previously wound wires without requiring large swinging strokes, as the preliminary winding pattern provides natural wire routing paths.
Solution Approach 2:
By segmenting the winding into alternating tooth sequences, the nozzle operates in a more controlled manner with smaller angular movements between adjacent teeth. This reduces the required swinging stroke compared to continuous winding around all teeth, preventing the need to increase the stator's inner diameter.
Data Source
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AI summary
In a stator winding method for winding conductive wires 8 around teeth 4a to 4f of a stator core 4 having 3n teeth 4a to 4f and 3n slots 5a to 5f by use of a bobbin machine 12 having three nozzles 13, the slots 5a to 5f on both sides of the teeth 4a, 4d, 4f in the nth winding process are formed, in respective slot portions on the side of the teeth 4a, 4d, 4f in the nth winding process, so that respective depths "A" are all smaller than respective depths "B" of the remaining portions. At the final stage of the nth winding process, the nozzles 13 are moved from the interior side of the slots 5a to 5f toward the inner circumferential side of the stator core 3 and furthermore, the conductive wires 8 are wound around the teeth 4b, 4d, 4f so that each gap 14 between the conductive wires 8 wound around the teeth 4b, 4d, 4f and the conductive wires 8 wound around the teeth 4a, 4c, 4e is smaller than an outer diameter of the nozzle 13.