Segmented Axial Fan Hub for Vibration Isolation
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Solution Overview
Problem
Axial flow fans in automotive cooling systems generate bothersome noise due to electromagnetic forces and resonances from electric motors, which are not effectively mitigated by existing designs.
Innovation Solution
The axial fan assembly incorporates a hub with radially extending connection structures and isolated members separated by slots, allowing for vibration isolation and decoupling from resonant modes, reducing sound radiation efficiency through flexible movement and energy dissipation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the fan is directly coupled to the electric motor, then the structure is simple and reliable, but the noise and vibration from the motor are transmitted to the fan
Solution Approach 1:
The hub is segmented into multiple isolated members (first, second, third isolated members) separated by slots, allowing each member to move independently to dissipate vibration energy while maintaining overall structural integrity
Solution Approach 2:
The slots act as intermediaries that decouple the isolated members from each other, allowing vibration isolation while the connection structures (screws, clips, or press-fit mechanisms) serve as intermediaries between the hub and motor rotating portion
2Ease of manufacture
If the hub is made as a single solid piece, then the manufacturing is simple and strong, but the vibration and noise cannot be isolated
Solution Approach 1:
The hub is divided into multiple isolated members connected by slots, creating a segmented structure that maintains manufacturing simplicity through injection molding while enabling vibration isolation through the separated components
Solution Approach 2:
The isolated members function as flexible elements within the rigid hub structure, allowing controlled movement to dissipate vibration energy while maintaining the overall structural form
3Object-generated harmful factors
If isolated members are added to the hub, then the noise and vibration are reduced, but the device complexity increases
Solution Approach 1:
The hub is segmented into isolated members that are integrated into a single injection-molded component, reducing assembly complexity while achieving vibration isolation through the segmented internal structure
Solution Approach 2:
The isolated members, slots, and connection structures are merged into a single integrated hub component manufactured by injection molding, combining multiple functions into one piece while maintaining vibration isolation capabilities
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 design achieves a significant reduction in sound pressure levels, typically by 10 dB, across various RPM ranges, effectively minimizing objectionable noise while maintaining airflow efficiency.
Implementation Method 1
the fan exhibits at least some level of noise and vibration originating from the electric motor
Implementation Method 2
isolated from the plurality of connection structures and the radially outer face portion by a plurality of slots
Data Source
AI summary
An axial fan assembly includes a hub, a plurality of connection structures, and a plurality of isolated members. The hub is rotatable about an axis of rotation and includes a radially extending face and a cylindrical portion extending axially from the face. The face includes a radially inner face portion and a radially outer face portion. The plurality of connection structures extends radially inwardly from the radially outer face portion and extends radially outward from the radially inner face portion. The plurality of isolated members extends radially outwardly from the radially inner face portion and is isolated from the plurality of connection structures and from the radially outer face portion by a plurality of slots.