Electric Fan Labyrinth Structure for Liquid Ingress Prevention
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Solution Overview
Problem
Conventional electric fans with labyrinth structures face limitations in enhancing waterproof performance and require tight dimensional tolerances and high assembly accuracy to prevent liquid ingress, which can be compromised if assembly accuracy is lower.
Innovation Solution
The introduction of volume expanding portions within the labyrinth structure of the electric fan, which allows liquids to pool and delay entry into the receiving space, thereby enhancing waterproof performance without the need for precise dimensional tolerances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a clearance is provided to form a labyrinth structure to prevent liquid entry, then waterproof performance is improved, but dimensional tolerances of the casing and impeller must be reduced (manufacturing precision worsens)
Solution Approach 1:
The invention introduces volume expanding portions that extend in the radial direction from the axial clearance, transforming a one-dimensional clearance barrier into a three-dimensional labyrinthine structure. This dimensional expansion increases the liquid path length and volume without requiring tighter axial tolerances between the impeller and casing.
Solution Approach 2:
The volume expanding portions are nested within the existing clearance space between the impeller and casing, utilizing the available volume efficiently. The protrusions from one component fit into the clearance of the other, creating a nested labyrinth structure that maximizes waterproofing within the given assembly envelope.
2Reliability
If a clearance is provided to form a labyrinth structure to prevent liquid entry, then waterproof performance is improved, but assembly accuracy of the impeller body and casing must be increased
Solution Approach 1:
By extending the waterproof barrier into the radial dimension through volume expanding portions, the invention compensates for potential assembly variations in the axial direction. The multi-dimensional labyrinth structure provides a longer liquid path that is less sensitive to axial positioning accuracy during assembly.
3Volume of moving object
If the thicknesses of the opposed wall portions are kept small, then the overall structure remains compact, but the volume of the labyrinth structure is reduced (waterproof performance worsens)
Solution Approach 1:
The volume expanding portions are nested within the clearance space rather than requiring additional wall thickness. This nested configuration allows the labyrinth structure to achieve large volume within the constraints of thin wall portions, maintaining overall compactness while enhancing waterproof performance.
Solution Approach 2:
The invention compensates for limited axial wall thickness by expanding the labyrinth structure in the radial direction. This dimensional shift allows sufficient labyrinth volume to be achieved without increasing the axial thickness of the impeller or casing wall portions.
Data Source
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AI summary
An electric fan is provided, including a labyrinth structure with increased performance of preventing entry of a liquid into a receiving space to receive a stator and a rotor. A clearance is defined between an opposed wall portion of a base and an opposed wall portion of an impeller body, which are opposed to each other in an axial direction of a rotary shaft, to form a labyrinth structure. The opposed wall portion of the base and the opposed wall portions of the impeller body are shaped to form a volume expanding portion within the clearance. The volume expanding portion is constituted from a groove portion for expanding the clearance, having a volume larger than other portions within the clearance .