Sound-Absorbing Duct Flange Structure to Prevent Sheet Compression
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Solution Overview
Problem
Conventional sound absorbing ducts experience degraded sound absorbing performance due to compression of sound absorbing sheets during crimping and molding processes, making it difficult to enhance their sound absorbing capabilities.
Innovation Solution
A duct design featuring groove-shaped members with flange portions that include a seal portion formed by crimping and an outer thick portion made from a thicker sound absorbing sheet, which is extended outward from the seal portion, along with an outer crimped portion to enhance sound absorption and structural integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the sound absorbing sheet is compressed during crimping of the flange portions and vacuum molding, then the duct can be formed with joined flange portions, but the original sound absorbing performance of the sound absorbing sheet is degraded
Solution Approach 1:
The flange portion is divided into two distinct segments: a seal portion (crimped region) for structural joining and an outer thick portion (uncompressed region) for sound absorption. This segmentation allows each part to fulfill its specific function without compromising the other, resolving the contradiction between structural integrity and sound absorbing performance.
Solution Approach 2:
Different regions of the flange portion are given different properties: the seal portion is crimped to provide strong joining capability, while the outer thick portion remains uncompressed to maintain high sound absorbing performance. This local differentiation of properties allows the single component to satisfy multiple conflicting requirements.
2Reliability
If a thicker sound absorbing sheet is used for the outer thick portion, then sound absorbing performance is enhanced, but the complexity of the manufacturing process increases
Solution Approach 1:
The sound absorbing sheet is prepared with an extended flange portion that has sufficient thickness before the molding process. This preliminary preparation ensures that the outer thick portion maintains its thickness through the vacuum molding process without requiring additional steps or complex tooling, thus enhancing sound absorption while avoiding manufacturing complexity.
Solution Approach 2:
The flange portion serves multiple functions simultaneously: it provides structural joining through crimping in the seal portion, maintains sound absorbing performance in the outer thick portion, and enables vacuum molding for duct formation. This multi-functionality reduces the need for separate components or complex manufacturing steps.
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 design effectively enhances sound absorbing performance by utilizing a thicker sound absorbing sheet for the outer thick portion, improving sound absorption coefficients and maintaining the structural integrity of the duct while preventing sheet compression, thus compensating for the performance loss in the duct wall.
Implementation Method 1
a pair of groove-shaped members which are formed of sound absorbing sheets
Implementation Method 2
vacuum molding or pressure molding each of the sound absorbing sheets into a groove shape
Data Source
AI summary
A duct of the present invention includes a pair of groove-shaped members which are formed of sound absorbing sheets and a pair of flange portions which are formed of parts of the pair of groove-shaped members that are extended outward from groove opening edges and which are joined in an overlaid state on each other when the pair of groove-shaped members are arranged such that groove openings are opposed to each other. The pair of flange portions includes a seal portion which is formed by crimping the sound absorbing sheets in parts of the flange portions along the groove opening edges and an outer thick portion which is extended outward from the seal portion and which is formed of the sound absorbing sheet thicker than the sound absorbing sheet of the seal portion.