Helmholtz Soundproof Structure with Rear Surface Plate
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Solution Overview
Problem
Existing soundproof structures using Helmholtz resonance face challenges in reducing size and thickness, particularly for low-frequency sound, as the rear surface volume needs to be increased, making it difficult to miniaturize while maintaining effective sound absorption.
Innovation Solution
A soundproof structure with a housing that includes a through hole and a rear surface plate, where the distance from the rear surface plate to the through hole is less than or equal to the hole's diameter, and the rear surface plate is positioned to extend the effective length of the through hole, allowing for a thinner design and lower resonance frequency without increasing the rear surface volume.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the rear surface volume is increased to reduce low-frequency sound, then the sound absorption efficiency is improved, but the size and thickness of the soundproof structure increase
Solution Approach 1:
The patent changes the geometric parameters of the through hole (diameter, length, position) to optimize the opening end correction distance. By adjusting these parameters, the effective length of the through hole is extended, which lowers the resonance frequency and improves low-frequency sound absorption without increasing the rear surface volume
Solution Approach 2:
The patent extends the through hole in the thickness direction (z-direction) and positions the rear surface plate at a specific distance from the opening surface. This dimensional arrangement creates a longer effective path for sound waves while maintaining a compact overall structure, effectively increasing the opening end correction distance without expanding the rear surface volume
2Length of moving object
If the thickness of the soundproof structure is reduced, then the compactness is improved, but the opening end correction distance is shortened
Solution Approach 1:
The patent positions the rear surface plate at a specific distance d from the opening surface in the thickness direction, and extends the through hole length L0. This creates an extended effective path for sound waves through strategic dimensional arrangement, achieving a longer opening end correction distance while maintaining a thin overall structure
Solution Approach 2:
The patent optimizes the parameters of the through hole (diameter Φ, length L0) and the distance d to maximize the opening end correction distance. By carefully selecting these parameters, the effective length of the through hole is extended, compensating for the reduced thickness of the soundproof structure
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 configuration enables a smaller and thinner soundproof structure that effectively reduces low-frequency sound, achieving a longer opening end correction distance and lower resonance frequency, thus allowing for more compact designs while maintaining sound absorption efficiency.
Implementation Method 1
a housing forming a space (16) inside and having a through hole (14) allowing the space (16) to communicate with an outside, and generating Helmholtz resonance by the space (16) and the through hole (14)
Data Source
AI summary
Provided are a soundproof structure and a soundproof unit that can be reduced in size and thickness in the soundproof structure using Helmholtz resonance. The soundproof structure that includes a housing forming a space therein and having a through hole that allows the space to communicate with an outside, and generates Helmholtz resonance by the space and the through hole, the soundproof structure includes a rear surface plate disposed at a position overlapping the through hole on the space side as viewed from a penetrating direction of the through hole, in which assuming that a diameter of the through hole is Φ and a distance from the rear surface plate to an opening surface of the through hole on the space side is d, d≤Φ is satisfied and d≤6 mm is satisfied.