Handheld Blower Fan With Uneven Blade Spacing for Frequency Reduction
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Solution Overview
Problem
Existing handheld blower fans generate unpleasant frequencies due to evenly spaced blades, leading to user discomfort.
Innovation Solution
The fan design incorporates unevenly spaced blades with alternating spacings to reduce perceived frequencies, and a fan hub with a tapered air guiding cone for increased efficiency and air flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If blades are evenly spaced circumferentially about the hub, then the fan structure is simple and easy to manufacture, but unpleasant frequencies are generated causing user discomfort
Solution Approach 1:
The patent applies asymmetry by configuring blades with non-uniform circumferential spacing about the hub. Specifically, at least one blade is positioned at a different angular distance from adjacent blades compared to other blade spacings. This asymmetric arrangement disrupts the generation of unpleasant frequencies while maintaining effective air movement, thereby resolving the contradiction between manufacturing simplicity and user comfort.
2Ease of manufacture
If a standard fan hub design is used, then manufacturing is simpler, but fan efficiency and air flow are reduced
Solution Approach 1:
The patent applies local quality by providing the hub with a specific geometric configuration featuring a curved outer surface with varying radius. The radius increases from a first value at a first angular position to a second value at a second angular position, creating locally optimized air flow paths. This non-uniform hub geometry enhances fan efficiency and air flow performance while remaining manufacturable, thus resolving the contradiction between manufacturing simplicity and productivity.
Data Source
AI summary
A fan includes a hub and a plurality of blades extending radially outwardly from the hub and spaced circumferentially about the hub. The plurality of blades includes a reference blade, a first blade, and a second blade. The reference blade is disposed after the first blade in a circumferential direction about the hub. The second blade is disposed after the reference blade in the circumferential direction. The first blade is circumferentially spaced a first distance from the reference blade. The second blade is circumferentially spaced a second distance from the reference blade. The first distance is greater than the second distance.