Fan Casing Inner Wall Geometry for Noise Reduction
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Solution Overview
Problem
Existing air-blow working machines, such as portable blowers, generate loud noise due to drive sounds from the engine and fan, which are not effectively mitigated by current designs.
Innovation Solution
The air-blow working machine incorporates a fan casing with an inner wall featuring a smooth surface on the fan side and a first concavo-convex portion on the drive unit side, increasing the surface area to reduce drive sounds while preventing airflow resistance, thus minimizing noise without compromising air blowing performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If acoustic materials like foaming resin are adhered onto the fan casing to reduce noise, then drive sounds are reduced, but the number of parts increases and assembly complexity increases
Solution Approach 1:
The concavo-convex portions are integrated directly into the fan casing structure, merging the noise reduction function with the existing casing. This eliminates the need for separate acoustic materials and reduces the number of parts while maintaining the noise reduction effect.
Solution Approach 2:
The fan casing serves multiple functions: it houses the fan, provides structural support, and incorporates noise reduction features through its concavo-convex portions. This multi-functionality eliminates the need for separate noise reduction components.
2Object-affected harmful factors
If the surface area of the inner wall is increased to reduce drive sounds, then noise is reduced, but airflow resistance may increase
Solution Approach 1:
The concavo-convex portions are strategically positioned on the inner wall surface where they effectively absorb drive sounds without creating significant airflow resistance. The local modification of surface geometry targets noise reduction in specific areas while maintaining overall airflow efficiency.
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 efficiently reduces drive sounds and noise emission while maintaining airflow performance, simplifying assembly by reducing the number of parts compared to using acoustic materials like foaming resin.
Implementation Method 1
drive sounds generated during a drive of an engine and a fan are diffused outside so that a noise in operating the air-blow working machine is loud. Therefore, it is desired to reduce the noise
Implementation Method 2
The inner wall has a smooth surface on the face thereof on the side of the fan, and a first concavo-convex portion on the face thereof on the side of the drive unit
Data Source
AI summary
The air-blow working machine comprises a fan provided in a fan casing and a drive unit to drive the fan, and discharges an airflow generated by the rotating fan. The fan casing has an inner wall disposed between the fan and the drive unit. A smooth surface is formed on the face of the inner wall on the side of the fan. A first concavo-convex portion is formed on the face of the inner wall on the side of the drive unit. Thereby, a noise is reduced without an influence upon performance for blowing air.