Rotating Electric Machine Rotor Cross Point Shifting
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Solution Overview
Problem
Conventional rotating electric machine rotors face issues with outer diameter enlargement and balance deterioration due to cross point positioning, requiring thickness changes in the winding drum portion and the use of tapes to prevent coil wire dropping.
Innovation Solution
A rotor design featuring a pair of pole cores with tapered nail-shaped magnetic poles and a bobbin with a U-shaped cross section, where the rotor coil is wound in multiple stages with cross points shifted in the circumferential direction between the lower coil field and mountain-wound coil field, allowing for balanced cross point positioning without changing the thickness of the winding drum portion or using tapes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the cross points in the coil field A and the cross points in the mountain winding portion are set substantially at the same position, then the winding structure is simplified, but the outer diameter at these cross points is enlarged
Solution Approach 1:
The patent shifts the cross points in the mountain winding portion to different angular positions compared to the coil field A, utilizing the angular dimension to distribute cross points circumferentially. This prevents radial stacking of cross points at the same position, thereby reducing outer diameter enlargement while maintaining winding structure simplicity.
2Area of stationary object
If the number of layers is increased, then the coil field coverage is improved, but the outer diameter enlargement cannot be completely absorbed by change in the thickness
Solution Approach 1:
Instead of increasing radial layers which would increase outer diameter, the patent distributes cross points of multiple layers in the angular direction. This allows multiple layers to coexist without proportional outer diameter increase, as cross points are spread circumferentially rather than stacking radially.
3Ease of manufacture
If the respective cross points concentrate in one direction almost at the same position, then the winding process is simplified, but the balance is deteriorated
Solution Approach 1:
The patent introduces asymmetric angular positioning of cross points in the mountain winding portion relative to the coil field A. This asymmetric distribution prevents concentration of cross points at one location, improving rotor balance while maintaining relatively simple winding processes through systematic angular offset.
Data Source
Figure 1~2
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AI summary
This rotating electric machine rotor 10 has a rotor coil 11 composed of; a lower coil field A wound around the outer circumference of a winding drum portion 17 of a bobbin 16; and a mountain-wound coil field B wound around the outer circumference of the lower coil field A. A cross point C in the mountain-wound coil field B and a cross point C in the lower coil field A are shifted from each other in the circumferential direction. Thus, it becomes possible to shift the cross point positions without changing the thickness of the winding drum portion 17 of the bobbin 16 and without using a tape or the like.