Waterproof Fan Resin Layout to Block Thermal-Stress Water Ingress
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Solution Overview
Problem
Existing waterproof fans with resin-covered electronic components face water ingress due to thermal stress-induced gaps between the resin and metal frames, which can compromise the circuit board's integrity.
Innovation Solution
A waterproof fan design featuring a rotor, stator, frame, circuit board, and positioning member, where the positioning member, made of a different resin, positions the circuit board away from the frame's inner wall, preventing water ingress by creating a gap between the resin and the frame, and using a separate resin for waterproofing that covers the stator and circuit board.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the circuit board is supported by the frame using a base-side protruding portion, then the circuit board is stably supported, but water can ingress through gaps created by thermal stress between the resin and metal frame
Solution Approach 1:
The support function is divided between two separate components: the base-side protruding portion of the frame provides mechanical support, while a separately provided waterproofing member (resin portion) fills the gap between the frame and circuit board to prevent water ingress. This segmentation allows each component to optimize its specific function without compromising the other.
Solution Approach 2:
A waterproofing member made of resin material is introduced as an intermediary element between the metal frame and the circuit board. This intermediary fills the thermal expansion gap that forms between the frame and circuit board, preventing water from penetrating through while allowing the frame to freely expand and contract with temperature changes.
2Object-affected harmful factors
If resin is used to cover the circuit board for waterproofing, then water resistance is improved, but thermal stress creates gaps between the resin and metal frame allowing water ingress
Solution Approach 1:
The waterproofing solution applies local quality by providing targeted protection only where needed - the waterproofing member is specifically positioned to fill the gap between the frame and circuit board, rather than requiring complete encapsulation of all components. This localized approach maintains waterproofing reliability while accommodating thermal expansion differences.
3Volume of moving object
If the circuit board is positioned close to the frame for compact design, then device size is reduced, but water can reach the circuit board through gaps along the frame
Solution Approach 1:
The waterproofing member serves as an intermediary barrier that enables the circuit board to be positioned close to the frame for compact design while simultaneously preventing water ingress. The resin-based waterproofing member fills the necessary gap space, allowing compact arrangement without compromising waterproofing reliability.
Data Source
AI summary
A waterproof fan includes: a rotor including a rotating blade capable of rotating about a rotation axis; a stator including a plurality of stator cores extending in a radial direction relative to the rotation axis, and a winding wound around each of the stator cores; a frame including a housing space opening toward one side of the rotation axis; a circuit board electrically connected to the winding and housed in the housing space; a waterproofing resin portion covering the stator and the circuit board to block the opening of the housing space; and a positioning member provided in the housing space and configured to position the circuit board at a position away from an inner wall of the housing space.