Rigid Cavity Wall Encapsulation for Sound Absorbing Material
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Solution Overview
Problem
Existing sound absorbing material encapsulation structures in miniature loudspeakers are prone to crushing due to the flexibility of the injection-molded mesh cloth, leading to reduced acoustic performance and contamination within the sound production device.
Innovation Solution
A sound absorbing material encapsulation structure featuring a rigid cavity wall with air permeability holes, a bottom plate, and a covering plate to prevent deformation and support the sound absorbing material, ensuring it is not crushed and maintains acoustic performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If flexible injection-molded mesh cloth is used to form the cavity, then the cavity can be easily manufactured and assembled, but the sound absorbing material is easily crushed and loses its function
Solution Approach 1:
The patent applies this principle in reverse - it uses a rigid shell (rigid cavity wall) instead of a flexible one to protect the sound absorbing material. The rigid cavity wall provides structural support that prevents the flexible mesh cloth from crushing the brittle sound absorbing material while still allowing the cavity to be formed through injection molding or hot pressing processes.
Solution Approach 2:
The patent creates a composite structure by combining the rigid cavity wall (made of rigid material) with the sound absorbing material (porous brittle material). This composite construction allows the rigid component to provide mechanical support while the sound absorbing material performs its acoustic function, solving the contradiction between structural integrity and acoustic performance.
2Object-affected harmful factors
If the cavity is sealed after filling sound absorbing powder, then the powder is protected from external contamination, but the powder is trapped inside and cannot be replaced if crushed
Solution Approach 1:
The patent divides the encapsulation structure into separable components: the rigid cavity wall, the bottom plate, and the covering plate. The covering plate is detachably connected to the rigid cavity wall, creating a segmented structure that allows the sound absorbing material to be accessed and replaced while maintaining protection during operation. This segmentation enables both contamination protection during use and easy replacement during maintenance.
Solution Approach 2:
The patent transitions from a static sealed structure to a dynamic structure where the covering plate can be detached and reattached. This dynamic design allows the encapsulation structure to adapt between two states: sealed for protection during operation and open for maintenance when the sound absorbing material needs replacement, resolving the contradiction between protection and repairability.
3Reliability
If the rigid cavity wall is made completely sealed, then the sound absorbing material is well protected, but air cannot flow in and out of the structure
Solution Approach 1:
The patent applies local quality by creating different regions in the rigid cavity wall with different properties. Most of the rigid cavity wall remains sealed to provide protection, while specific local regions contain air permeability holes that allow air flow. This localized modification enables the structure to simultaneously achieve both protection and air flow functionality without compromising overall integrity.
Solution Approach 2:
The patent incorporates porous characteristics into the rigid cavity wall by forming air permeability holes within it. These holes create a porous structure that allows air to pass through while the surrounding rigid material maintains structural integrity and protection. This application of porous material principles enables the rigid wall to perform both protective and breathable functions.
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 rigid structure prevents the sound absorbing material from being deformed or crushed, maintaining acoustic performance and preventing contamination within the sound production device, while allowing air to flow and balance pressure.
Implementation Method 1
the rigid cavity wall is provided with air permeability holes arranged in an array, and the air permeability holes are configured to form a channel for air to flow in and out of the sound absorbing material encapsulation structure
Implementation Method 2
The Harp powder pack may increase the virtual acoustic volume of the rear cavity, so that the acoustic module with a smaller rear cavity can have the same acoustic performance as other modules
Data Source
AI summary
Provided are a sound absorbing material encapsulation structure for a sound production device, and a sound production device. The sound absorbing material encapsulation structure comprises: a rigid cavity wall enclosed to form a cavity of the sound absorbing material encapsulation structure, the cavity is configured to accommodate a sound absorbing material, the rigid cavity wall is provided with air permeability holes arranged in an array, the air permeability holes are configured to form a channel for air to flow in and out of the sound absorbing material encapsulation structure, diameters of air permeability holes are smaller than a diameter of sound absorbing material; a bottom plate sealed and connected to one end surface of rigid cavity wall, the bottom plate is configured to support the sound absorbing material; a covering plate provided to cover another end surface of rigid cavity wall and sealed and connected to the rigid cavity wall.