Stator Coil Arrangement for Motor Space Factor
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Solution Overview
Problem
Concentrated winding motors face a decrease in space factor due to the need for clearance between coils, which is exacerbated by shorter distances between teeth in the circumferential direction of the stator core.
Innovation Solution
A stator design featuring alternately arranged outer and inner coils, where outer coils are in a non-fixed state and inner coils are in a fixed state, eliminating the need for clearance between them and allowing for improved packing density without interference, using a combination of trapezoidal and rectangular teeth to enhance heat dissipation and reduce part count.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If clearance is provided between adjacent coils along the tooth extension direction for insulation, then coil insulation is ensured, but the space factor of coils decreases
Solution Approach 1:
The patent transitions from providing clearance in the axial direction (along tooth extension) to providing clearance in the circumferential direction (between adjacent teeth). This dimensional change allows coils to be densely packed axially while maintaining insulation through circumferential spacing, thereby resolving the contradiction between insulation reliability and space factor.
Solution Approach 2:
Instead of insulating coils by separating them axially along the tooth, the invention inverts the approach by insulating them through circumferential separation between adjacent teeth. This inversion of the insulation strategy eliminates axial clearance requirements while maintaining insulation effectiveness.
2Volume of moving object
If the distance between adjacent teeth in the circumferential direction is reduced, then the motor size is reduced, but the space factor decreases further
Solution Approach 1:
The patent compensates for reduced circumferential tooth spacing by utilizing the axial dimension for coil placement. Coils are positioned at different axial locations (base side vs. tip side of teeth), allowing dense circumferential packing while maintaining adequate insulation clearance in the axial direction, thus preserving space factor despite reduced motor size.
Solution Approach 2:
The invention implements a nested arrangement where coils are positioned at different axial levels (inner coils at base side, outer coils at tip side). This nesting in the axial dimension allows the motor to achieve compact circumferential dimensions while maintaining sufficient coil space factor through axial stratification.
3Ease of manufacture
If all coils are arranged on the tip side of teeth, then assembly is simplified, but heat dissipation performance deteriorates
Solution Approach 1:
The patent segments the coil arrangement into two distinct groups: inner coils positioned at the base side of teeth and outer coils positioned at the tip side. This segmentation creates axial separation that improves heat dissipation pathways while maintaining structured assembly simplicity through the organized inner-outer coil configuration.
Solution Approach 2:
Different regions of the tooth structure are utilized for different coil types: the base side accommodates inner coils while the tip side accommodates outer coils. This local differentiation optimizes heat dissipation by distributing coils across different thermal zones, while the systematic arrangement preserves manufacturing simplicity.
Data Source
AI summary
A stator includes multiple coils. The coils include multiple outer coils arranged on the base side of teeth and multiple inner coils arranged on the tip side of the teeth. The outer coils and the inner coils are alternately arranged along the circumferential direction of a stator core. Each coil winding of the outer coils is formed in a non-fixed state, and each coil winding of inner coils is formed in a fixed state.