Motor Coil Substrate Using Flexible PCB for High Space Factor
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Solution Overview
Problem
Existing motor coil technologies face challenges in achieving high efficiency and space factor due to the difficulty in winding thin wire coils with high positional accuracy, leading to decreased space factor and potential wire breakage.
Innovation Solution
A motor coil substrate is developed using a flexible substrate with coils wound in a cylindrical shape, featuring central spaces with wirings surrounding them, and openings through the substrate, allowing for increased space factor and uniform thickness by positioning wiring groups perpendicular to the rotation direction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If thin wire coils are wound to achieve high space factor, then the space factor increases, but the manufacturing precision and reliability decrease due to difficulty in winding with high positional accuracy and potential wire breakage
Solution Approach 1:
The patent replaces the mechanical wire winding process with a printed circuit board fabrication process. Coils are formed by depositing conductive material patterns on a flexible substrate using standard PCB manufacturing techniques (photoresist coating, exposure, development, plating), eliminating the need for mechanical wire winding while achieving precise coil geometry and positioning.
Solution Approach 2:
The patent changes the physical state and form of the coil structure from three-dimensional wound wire to two-dimensional planar traces on a flexible substrate. This parameter change allows coils to be formed with precise dimensions through photolithography and plating processes, achieving high manufacturing precision without the complexities of thin wire manipulation.
2Quantity of substance
If thin wire coils are wound to increase space factor, then the space factor increases, but the reliability decreases due to potential wire breakage
Solution Approach 1:
The patent replaces fragile mechanical wire winding with a robust printed circuit board fabrication process. Conductive traces are formed through photoresist coating, exposure, development, and electroplating, creating solid copper or copper-alloy coil structures that are inherently more reliable and resistant to breakage than thin wire coils.
Solution Approach 2:
The patent uses composite material structures where a flexible substrate (polyimide or similar) supports thick copper or copper-alloy traces. This composite construction provides both the flexibility needed for motor application and the mechanical strength of thick metal traces, eliminating wire breakage issues while maintaining high space factor.
3Power
If coils are wound in cylindrical shape, then the motor efficiency improves, but the device complexity increases due to difficulty in maintaining uniform thickness and preventing substrate overlap
Solution Approach 1:
The patent forms the flexible substrate and coil structure into a cylindrical shape that fits around the motor rotor. The cylindrical geometry is achieved by winding the flat flexible substrate with coil patterns around the rotor, creating a curved coil structure that optimizes magnetic field interaction and motor efficiency while maintaining manufacturing simplicity through standard PCB fabrication followed by cylindrical assembly.
Solution Approach 2:
The patent transitions from two-dimensional planar coil patterns on a flat substrate to three-dimensional cylindrical coil structures. By winding the flexible substrate with printed coil patterns around the rotor in a cylindrical configuration, the design achieves optimized motor efficiency through curved geometry while the flexible substrate naturally accommodates the dimensional transformation without complex assembly.
Data Source
AI summary
A motor coil substrate includes a coil substrate that is wound in a cylindrical shape and includes a flexible substrate and coils formed on the flexible substrate such that the flexible substrate has a first end and a second end on an opposite side with respect to the first end and that the coils are arrayed from the first end to the second end of the flexible substrate. The coils are formed such that each of the coils has a central space and includes wirings surrounding the central space, and the flexible substrate has openings formed such that each of the openings is penetrating through the flexible substrate and positioned in the central space of a respective one of the coils.