Vehicle Ceiling Material With Tunable Ventilation for Sound Absorption
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Solution Overview
Problem
Existing molded ceiling materials for vehicles lack the ability to control sound-absorption performance effectively, as they either block ventilation with impermeable films or require increased thickness to improve sound-absorption, which is not adaptable to varying sound-absorption characteristics of different vehicles.
Innovation Solution
A molded ceiling material with a ventilation control mechanism, featuring a film layer with perforated ventilation holes that can adjust ventilation volume by changing the opening rate, number, and arrangement of holes, allowing controlled sound absorption according to the vehicle's sound-absorption characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If an air-impermeable film is used to prevent thermosetting resin penetration, then structural integrity is improved, but sound-absorption performance deteriorates due to blocked ventilation
Solution Approach 1:
The patent uses a porous sound-absorption material with controlled pore structure that allows sound wave penetration while maintaining structural integrity. The porous configuration enables sound to reach the polyurethane foam core for absorption without requiring an air-impermeable film, thus resolving the contradiction between structural strength and sound-absorption performance.
Solution Approach 2:
The patent employs a composite structure combining a polyurethane foam core with a fiber reinforcement layer (glass mat or organic fiber) impregnated with thermosetting resin. This composite configuration provides both structural integrity and sound-absorption capability, eliminating the need for an air-impermeable film while maintaining both required properties.
2Object-affected harmful factors
If the thickness of the polyurethane foam is increased to improve sound-absorption, then sound-absorption performance is improved, but weight and device complexity increase
Solution Approach 1:
The patent optimizes the thickness parameter of the polyurethane foam core to achieve sufficient sound-absorption performance without excessive weight. By carefully selecting and controlling the foam thickness within a specific range, the design achieves effective sound absorption while minimizing weight and avoiding unnecessary device complexity.
3Strength
If a fiber reinforcement layer is added to ensure rigidity, then structural rigidity is improved, but manufacturing complexity increases due to resin impregnation requirements
Solution Approach 1:
The patent controls the resin content and impregnation degree of the fiber reinforcement layer to achieve optimal rigidity while simplifying manufacturing. By parameterizing the resin saturation level and fiber mat density, the design attains sufficient structural rigidity without requiring complex multi-step impregnation processes, thus improving ease of manufacture.
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 solution enables flexible control of sound-absorption performance regardless of substrate layer thickness, providing tailored sound-absorption characteristics to match the specific acoustic needs of each vehicle, while preventing excessive ventilation.
Implementation Method 1
sound generated in the vehicle cabin can be absorbed by the substrate layer of the ventilation control mechanism
Implementation Method 2
The substrate layer includes a porous core layer
Data Source
AI summary
A molded ceiling material for vehicles having a substrate layer containing a porous core layer, a surface member and a ventilation control mechanism to control the ventilation volume that is vented from a cabin side of the surface member to the substrate layer. Sound generated in the vehicle cabin is absorbed by the substrate layer through the ventilation control mechanism. That is, the molded ceiling material is equipped with sound-absorption performance for sound from the cabin side of the vehicle. If the sound-absorption rate is increased, the ventilation volume to the substrate layer is increased. If the sound-absorption rate is decreased, the ventilation volume to the substrate layer is reduced. The sound-absorption rate of the molded ceiling material can be controlled regardless of the thickness of the substrate layer. Consequently, the molded ceiling materials for vehicles can be provided with sound-absorption performance corresponding to the sound-absorption characteristics of the vehicle.