Vacuum Cleaner Diffuser Wing Geometry for Lower BPF Noise
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Solution Overview
Problem
Conventional fan assemblies in vacuum cleaners generate offensive high-frequency blade passing frequency (BPF) noise due to air whirlpools formed at the diffuser entrance, which is not adequately addressed by existing noise reduction methods.
Innovation Solution
The fan assembly features a diffuser wing design with angled and vertical parts, where the leading end of the diffuser wing forms an entrance with a predetermined angled part and a vertically extending part, preventing air whirlpools at both the upper and lower ends of the diffuser channel entrance, thereby reducing noise generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If diffuser wings with the same angle are used, then manufacturing is simplified, but BPF noise increases due to frequency superposition
Solution Approach 1:
The patent applies asymmetry by designing diffuser wings with different angles - specifically, the leading end has a first angle while the trailing end has a second angle that is different from the first. This angular asymmetry prevents frequency superposition and reduces BPF noise while still maintaining manufacturability through precise angular specifications.
Solution Approach 2:
The patent changes the angular parameters of the diffuser wings - specifying that the leading end angle differs from the trailing end angle. By modifying these geometric parameters, the patent reduces BPF noise through frequency dispersion while maintaining reasonable manufacturing complexity through well-defined angular specifications.
2Object-affected harmful factors
If the impeller upper end protrudes more than the lower end, then air whirlpool at the diffuser entrance is reduced, but the structure becomes more complex
Solution Approach 1:
The patent applies asymmetry to the impeller by making the upper end protrude more than the lower end, creating an asymmetric geometry that effectively reduces air whirlpool formation at the diffuser entrance. This asymmetric design, while slightly more complex, provides significant noise reduction benefits.
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
This design significantly reduces BPF noise by approximately 8dB compared to conventional designs, maintaining consistent suction force while minimizing air whirlpools and noise at the diffuser entrance.
Implementation Method 1
The impeller is connected to a rotary shaft of the motor 9 and rotated by the motor 9, thereby generating the suction force for drawing in the air
Implementation Method 2
The diffuser 8 induces the air being discharged from the impeller toward the motor 9
Implementation Method 3
the drawn-in air cools the motor 9 and exits to the outside
Implementation Method 4
generates a suction force that draws in dust together with ambient air, and then separates and collects the dust from the air
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
A fan assembly (400) for a vacuum cleaner (1), comprising a motor (100), an impeller (200) rotatably coupled to the motor (100), and having a plurality of impeller wings (230), and a diffuser (300) having a plurality of diffuser wings (310) arranged along an outer circumference of the impeller (280). The plurality of diffuser wings (310) includes first and second parts, the second part extending from an angle of the first part (310A) adjacent to the outer circumference of the impeller.