Centrifugal Blower Diaphragm Sharp Edge Noise Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Centrifugal blower units in motor vehicle air conditioning systems produce high noise emissions, which is a concern for comfort and safety, and existing solutions have not provided a satisfactory reduction in noise levels.
Innovation Solution
A centrifugal blower unit design featuring a spiral housing with a bell mouth region and a radially inward diaphragm having a beveled diaphragm end region, where the diaphragm end is configured with a sharp edge or specific angles to optimize air flow and reduce noise, with the diaphragm overlapping the fan wheel blades to minimize axial air strikes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If a radial diaphragm is added to the spiral housing, then noise emission is reduced, but device complexity increases
Solution Approach 1:
The diaphragm is segmented into a first diaphragm portion extending radially inward and a second diaphragm portion extending axially forward, with the second portion further segmented into multiple radially spaced apart edges. This segmentation allows the diaphragm to effectively manage air flow and reduce noise while maintaining a relatively simple overall structure that can be integrated into the existing spiral housing.
2Object-generated harmful factors
If the diaphragm end region is beveled, then noise reduction is improved, but manufacturing precision requirements increase
Solution Approach 1:
The diaphragm is configured with different geometric properties in different regions: the first diaphragm portion has a radial extension, the second diaphragm portion has an axial extension with beveled surfaces, and multiple edges are positioned at different radial locations. This local differentiation of geometric properties allows the diaphragm to optimize noise reduction performance in specific areas while maintaining manufacturability through standardized fabrication processes.
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 noise levels within the vehicle interior, offering potential for cost and space savings in soundproofing measures while minimizing annoying noise for passengers.
Implementation Method 1
In the blower, the air is accelerated by the rotating fan wheel and finally blown out in a tangential direction from the spiral housing
Implementation Method 2
The bell mouth region corresponds on the inside to the shape of the fan wheel and optimizes the air flow processes by preventing secondary currents
Data Source
AI summary
A centrifugal blower unit for motor vehicle air conditioning systems having a fan wheel (8) in a spiral housing (1), wherein the spiral housing (1) corresponds to the shape of the fan wheel (8) and has a bell mouth region (3) and an axial intake opening (2), wherein a diaphragm (4) is arranged at the bell mouth region (3) of the spiral housing (1), being radially inward, whose diaphragm end region (5) bordering the intake opening (2) has at least one sharp edge.