Segmented Metallic Blank Axial Fan Impeller Hub
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Solution Overview
Problem
Axial fan impellers with tubular hubs face mechanical stress issues during assembly, hindered heat dissipation, and condensation buildup due to the expansion of metallic blanks and plastic encapsulation.
Innovation Solution
A segmented metallic blank with alternating diameters and integrated webs and pockets within the hub for reduced mechanical stress, enhanced stability, and improved condensation runoff and cooling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a metallic blank is pressed onto the rotor to fasten the hub, then the hub can be securely fastened to the rotor, but high mechanical stresses occur in the hub causing potential breakage
Solution Approach 1:
The metallic blank is divided into multiple segments (first and second portions) with alternating larger and smaller diameters. This segmentation allows the blank to deform in a controlled manner during pressing, distributing the mechanical stress across multiple regions rather than concentrating it in a single continuous structure, thereby reducing the risk of hub breakage while maintaining secure fastening.
Solution Approach 2:
Different portions of the metallic blank have different diameters (alternating larger and smaller sections). This local variation in geometry allows specific regions to deform more easily during pressing while other regions maintain structural integrity, optimizing the balance between fastening strength and stress distribution.
2Stability of the object's composition
If a plastic encapsulation is used to surround the metallic blank, then the hub structure is formed and maintained, but heat dissipation from the rotor is hindered
Solution Approach 1:
The plastic encapsulation is designed as a thin-walled structure that provides structural stability to the hub while maintaining sufficient thermal conductivity. The thin film approach allows heat to pass through the plastic material more effectively, reducing the insulating effect and improving heat dissipation from the rotor.
3Strength
If the hub is formed as a solid plastic encapsulation, then structural integrity is maintained, but condensation that forms cannot run off
Solution Approach 1:
The plastic encapsulation incorporates drainage channels or porous structures that allow condensation to flow through the hub material. These integrated drainage pathways enable condensation to run off while the overall structural integrity of the hub is maintained through the encapsulation design.
4Strength
If the metallic blank is expanded during pressing-on, then the hub is securely fastened to the rotor, but high mechanical stresses cause the impeller to break
Solution Approach 1:
The segmented metallic blank with alternating diameters is designed to expand in a controlled, stepwise manner during pressing. Each segment can deform independently, distributing the expansion stresses across multiple regions and preventing stress concentration that would lead to impeller breakage, while still achieving secure fastening.
Solution Approach 2:
The alternating diameter design of the metallic blank anticipates the stress distribution needs during pressing. The larger diameter portions provide structural cushioning and stress distribution, while the smaller portions allow for controlled expansion, preventing catastrophic failure before the fastening is complete.
Data Source
AI summary
An impeller for an axial fan of the type adapted to be pressed onto a rotating rotor comprising a number of blades. The blades protrude radially outward from a substantially tubular hub, which carries the blades and is adapted to be pressed onto the rotating rotor. A substantially cylindrical blank is arranged inside the hub where the blank forms alternately arranged first and second portions. The first portions have a greater inside diameter than the inside diameter of the second portions.