Dual-Sided Motor Coil Substrate Layout for Uniform Circular Winding
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Solution Overview
Problem
Existing motor coil substrates wound in a circumferential direction often result in polygonal cylindrical shapes with non-uniform thickness, leading to interference with internal magnets and reduced heat dissipation due to varying gaps between the coil substrate and yoke, which compromises motor performance.
Innovation Solution
A motor coil substrate is formed by winding a flexible substrate with coils on both surfaces, where the first surface is positioned on the inner circumferential side and the second surface on the outer side, and a gap is intentionally created between specific layers to achieve a cylindrical shape with a perfect circular cross-section, preventing short circuits and maintaining consistent gaps for enhanced heat dissipation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If the coil substrate is wound in a circumferential direction to form a cylindrical shape, then the motor structure is compact and efficient, but the thickness becomes non-uniform resulting in a polygonal cross-section instead of a perfect circle
Solution Approach 1:
The coil substrate is divided into multiple independent coil units (first coil, second coil, third coil, fourth coil) that are arranged in a specific sequence. Each coil unit consists of windings on both the first surface and second surface of the flexible substrate. This segmentation allows the wound structure to achieve a more uniform cylindrical shape with reduced polygonal distortion, as the multiple alternating surfaces distribute the thickness variation more evenly around the circumference.
Solution Approach 2:
The patent employs an asymmetric arrangement where the first and second wirings are positioned on opposite surfaces of the flexible substrate, creating an alternating pattern (first surface, second surface, first surface, second surface) during winding. This asymmetric configuration of conductive paths on both surfaces helps balance the mechanical stress and thickness distribution, enabling the formation of a more circular cross-section compared to single-surface winding structures.
2Temperature
If the coil substrate is wound tightly without gaps between layers, then the structural integrity is high, but heat dissipation is reduced due to varying gaps between the coil substrate and yoke
Solution Approach 1:
The patent introduces gaps at specific locations between certain layers of the wound coil substrate, rather than maintaining uniform tight winding throughout. These localized gaps are strategically positioned to ensure consistent spacing between the coil substrate and the yoke, optimizing heat dissipation pathways in critical areas while maintaining structural integrity in other regions. The gaps allow for thermal expansion and improve thermal coupling with the yoke.
3Shape
If the first surface is positioned on the inner circumferential side and the second surface on the outer side during winding, then the cylindrical shape with perfect circular cross-section is achieved, but the manufacturing complexity increases
Solution Approach 1:
The flexible substrate is pre-designed with the first and second wirings positioned on opposite surfaces in an alternating pattern before winding. This preliminary arrangement of conductive paths on both surfaces of the flexible substrate ensures that when wound, the first surface and second surface naturally alternate in the circumferential direction, achieving a uniform cylindrical shape with circular cross-section. The pre-planned symmetric layout simplifies the winding process by eliminating the need for complex real-time adjustments during manufacturing.
Data Source
AI summary
A motor coil substrate includes a coil substrate including a flexible substrate and coils such that the coils include first wirings formed on a first surface of the flexible substrate and second wirings formed on a second surface of the flexible substrate on the opposite side. The coil substrate is wound N turns where N is an integer of 2 or more in a circumferential direction such that the first surface of the flexible substrate is positioned on an inner circumferential side of the coil substrate, the second surface of the flexible substrate is positioned on an outer circumferential side of the coil substrate, and a gap is formed between an M-th layer where M is an integer equal to or larger than 1 and less than N and an (M+1)-th layer from an inner side of N circumferential layers formed by winding the coil substrate N turns.