Motor Bobbin Composite Structure for Heat Dissipation
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Solution Overview
Problem
Conventional motor bobbins made of synthetic resin fail to meet the requirements of increased efficiency and power output in motor generators due to limitations in thickness, mechanical strength, heat resistance, and heat dissipation, especially in large-sized hybrid vehicle or electric automobile applications, where they tend to crack due to temperature changes and do not efficiently transmit heat from the coil to the core member.
Innovation Solution
A motor bobbin manufacturing method involving injection molding with an insulating sheet and a core member, where the insulating sheet is impregnated with a molded resin article, eliminating the need for adhesive agents and ensuring strong bonding, using aramid paper and a polymer with amide bonds for enhanced mechanical and thermal properties, and forming grooves for precise coil positioning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a synthetic resin bobbin is made thinner to increase coil space factor and power output, then the power output increases, but the mechanical strength and heat resistance deteriorate
Solution Approach 1:
The invention uses a composite structure combining insulating paper (aramid fiber-based) with molded resin articles. The insulating paper provides mechanical strength and dimensional stability, while the molded resin provides insulation and heat resistance. This composite approach enables the bobbin to be made thinner without sacrificing mechanical strength, thereby increasing coil space factor and power output.
2Temperature
If a synthetic resin bobbin is made thinner to improve heat dissipation to the core member, then heat dissipation improves, but the bobbin cannot follow core member expansion due to temperature changes, causing cracks
Solution Approach 1:
The invention changes the material parameters by using insulating paper with specific thermal expansion characteristics that match the core member. The aramid fiber-based insulating paper has low thermal expansion, allowing it to follow the core member's expansion during temperature changes without causing cracks, while still enabling effective heat dissipation to the core member.
Solution Approach 2:
The invention addresses thermal expansion mismatch by selecting insulating paper material whose thermal expansion properties are compatible with the core member. This allows the bobbin structure to accommodate temperature-induced dimensional changes of the core member without generating harmful stresses or cracks, while maintaining thin profile for heat dissipation.
3Ease of manufacture
If conventional synthetic resin bobbins are used, then the manufacturing process is simple, but the bobbin thickness cannot be reduced below 0.6 mm, limiting power output increase
Solution Approach 1:
The invention segments the bobbin into two functional parts: insulating paper layers providing mechanical strength and dimensional stability, and molded resin articles providing insulation and structural support. This segmentation allows each material to be optimized for its specific function, enabling the overall bobbin thickness to be reduced below the conventional 0.6 mm limit while maintaining manufacturability through established lamination and molding processes.
4Power
If the bobbin thickness is reduced to increase coil space factor, then power output increases, but the withstand voltage and partial discharge resistance may deteriorate
Solution Approach 1:
The composite structure of insulating paper and molded resin articles provides both mechanical strength and electrical insulation properties. The molded resin articles are specifically designed with sufficient thickness and material properties to maintain adequate withstand voltage and partial discharge resistance, while the overall bobbin thickness is reduced by optimizing the distribution and thickness of each composite layer, thereby increasing coil space factor and power output.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The resulting motor bobbin achieves a thin profile, high mechanical strength, effective heat dissipation, and improved power output by efficiently transmitting heat from the coil to the core member, while maintaining structural integrity and preventing coil faults, thus addressing the limitations of conventional synthetic resin bobbins.
Implementation Method 1
forming the motor bobbin by injection molding wherein the insulating sheet and a core member are arranged in a cavity of an injection mold and a resin is injected into the cavity
Implementation Method 2
having good and close contact with the core member to efficiently transmit heat generated by the coil to the core member (heat dissipation properties)
Data Source
AI summary
In a method for manufacturing a motor bobbin around which a coil is wound, an insulating sheet and a core material are disposed within the cavity of an injection mold, and the motor bobbin is formed by the injection mold into which a resin is injected. The motor bobbin consists of the insulating sheet and a resin molded body.