Soundproof Structure with Membrane Vibration and Helmholtz Resonance
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Solution Overview
Problem
Existing soundproof structures fail to effectively reduce high-frequency noise generated by electronic apparatus and electric motors, as they either require large amounts of porous sound absorbing materials or are not efficient in reducing specific frequency sounds, and existing combinations of Helmholtz resonance and membrane vibration do not adequately address noise across multiple frequency bands in limited installation spaces.
Innovation Solution
A soundproof structure incorporating a membrane-like member, a plate-like member with through-holes, and a rigid support that allows membrane vibration and Helmholtz resonance, where the fundamental frequencies of both mechanisms are carefully tuned to ensure the sound absorption coefficient is higher in high-order vibration modes than in fundamental modes, allowing for efficient absorption of noise across multiple frequency bands within a compact and lightweight design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If porous sound absorbing materials are used to reduce noise, then sound reduction effect is obtained in wide frequency range, but large amount of material is required and installation space increases
Solution Approach 1:
The patent changes the sound absorption mechanism from porous absorption to resonance-based absorption (Helmholtz resonance and membrane vibration). By adjusting resonance frequencies and combining different absorption mechanisms, effective sound reduction is achieved in limited space without requiring large volumes of porous material.
Solution Approach 2:
The patent combines multiple sound absorption mechanisms (Helmholtz resonance structures and membrane vibration structures) into a composite soundproofing system. This composite approach allows simultaneous targeting of different frequency ranges, achieving broad-spectrum noise reduction while maintaining compact dimensions.
2Reliability
If porous sound absorbing body is used, then sound with wide frequency range is reduced, but specific frequency noise becomes more audible prominently
Solution Approach 1:
The patent transitions from broadband porous absorption to targeted resonance absorption. By carefully selecting and adjusting the resonance frequencies of Helmholtz and membrane structures, the system effectively targets specific noise frequencies while maintaining overall noise reduction, preventing any single frequency from dominating.
Solution Approach 2:
The patent divides the sound absorption function into multiple specialized components: Helmholtz resonance structures for certain frequency ranges and membrane vibration structures for other ranges. This segmentation allows each component to optimize its performance for specific frequencies, collectively achieving comprehensive noise reduction without frequency dominance.
3Reliability
If sound reduction means using Helmholtz resonance or membrane vibration is used, then specific frequency sound is reduced more significantly, but noise across multiple frequency bands is not adequately addressed in limited installation spaces
Solution Approach 1:
The patent merges Helmholtz resonance structures and membrane vibration structures into a unified soundproofing system. The Helmholtz structures target specific frequency ranges while membrane structures handle complementary ranges, creating a synergistic effect that covers broad frequency bands within compact dimensions suitable for limited installation spaces.
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 structure achieves significant noise reduction across a wide frequency range, including high-frequency sounds, while maintaining a small and lightweight design, effectively addressing the limitations of previous technologies by enhancing sound absorption coefficients in high-order vibration modes and providing independent control over absorption frequencies.
Implementation Method 1
the membrane-like member is supported by the support so as to perform membrane vibration
Implementation Method 2
the plate-like member having the through-hole, the support, and the first space form a second sound absorbing portion that absorbs a sound by Helmholtz resonance
Data Source
AI summary
Provided is a soundproof structure that is small and light and can reduce a noise with a high specific frequency of a sound source at a plurality of frequencies at the same time. The soundproof structure has a membrane-like member, a plate-like member that is disposed to face the membrane-like member and in which at least one through-hole is formed, and a support that is formed of a rigid body and supports the plate-like member and the membrane-like member, in which the membrane-like member is supported by the support so as to perform membrane vibration, in which a rear surface space is provided between the membrane-like member and the plate-like member, in which a first space is provided on a side opposite to the rear surface space with the plate-like member sandwiched therebetween, in which the membrane-like member, the support, the plate-like member, and the rear surface space form a first sound absorbing portion that absorbs a sound by membrane vibration, in which the plate-like member, the support, and the first space form a second sound absorbing portion that absorbs a sound by Helmholtz resonance, and in which assuming that a fundamental frequency of membrane vibration of the membrane-like member in a case where the plate-like member is regarded as a rigid body in which the through-hole is not formed in the first sound absorbing portion is fm1 and a fundamental frequency of Helmholtz resonance of the second sound absorbing portion is fh1, fm1<fh1 is satisfied.