Rotary Machine Fan With Progressive Blade Geometry
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Solution Overview
Problem
Rotary electrical machine fans produce substantial noise due to harmonic generation, which is not effectively mitigated by conventional asymmetric blade positioning, necessitating improved fan designs to reduce noise and enhance user comfort.
Innovation Solution
A fan design with progressively varying blade characteristics such as spacing angles, lengths, and angles of inclination, applied to at least three consecutive blades, which reduces harmonic generation and noise, with optional progressive material distribution to balance the fan and maintain adequate air circulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If asymmetric blade positioning is used to avoid harmonics, then noise reduction is partially achieved, but harmonics still emerge due to environmental factors and the solution is not guaranteed
Solution Approach 1:
The patent applies asymmetry by making each blade unique with different characteristics (length, height, spacing angle, or inclination angle) compared to other blades. This breaks the symmetry that causes harmonic generation, while the progressive variation ensures consistent noise reduction without relying on environmental factors.
Solution Approach 2:
The patent applies local quality by varying specific characteristics of individual blades (each blade has unique length, height, or angular positioning) rather than applying a uniform asymmetric design to all blades. This localized variation ensures that each blade interacts differently with the air flow, eliminating harmonics more effectively.
2Object-affected harmful factors
If progressive blade characteristics are applied to reduce noise, then harmonic elimination is improved, but blade manufacturing complexity increases
Solution Approach 1:
The patent applies parameter changes by systematically varying one or more blade parameters (length, height, spacing angle, or inclination angle) in a progressive sequence across consecutive blades. This controlled parameter variation achieves noise reduction while maintaining manufacturability through defined geometric progressions rather than arbitrary complex shapes.
3Object-affected harmful factors
If blade characteristics are made progressive for all blades, then noise reduction is maximized, but manufacturing precision requirements increase
Solution Approach 1:
The patent applies periodic action through the progressive sequence of blade characteristics that repeats the pattern of variation across consecutive blades. This systematic periodic variation in blade parameters (such as increasing length or height in a defined sequence) maintains manufacturing precision through repeatable patterns while achieving comprehensive noise reduction across all blades.
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 progressive blade design significantly reduces noise, particularly during idling, improving user comfort and reducing noise-related issues, while maintaining effective air circulation and balancing the fan for reduced weight and production costs.
Implementation Method 1
substantial noise can be produced by the mechanism... In order to avoid the emergence of harmonics, and thus of noise caused by the fan
Data Source
AI summary
A fan of a rotary electric machine. The fan has an axis of rotation and comprises a plurality of blades (101). At least one characteristic of the blades is variable in the direction of a circumference of the fan around the axis of rotation for at least four consecutive blades. The at least one characteristic is selected from the group comprising a spacing angle between a straight line passing radially via a characteristic point of one of the blades and the axis of rotation of the fan and a straight line passing via a corresponding characteristic point of an adjacent blade and the axis of rotation of the fan, a height of the blade, a length of the blade, and an angle of inclination between a straight line passing via two characteristic points of a blade, and a straight line passing via two corresponding characteristic points of an adjacent blade.