Vehicle Transducer Mounting Structure for Low-Frequency Isolation
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Solution Overview
Problem
Existing mounting architectures for electrodynamic transducers in motor vehicle compartments do not optimize low-frequency transmission and fail to provide effective insulation against vehicle rolling noise.
Innovation Solution
A mounting architecture featuring a decoupling frame with increasing stiffness, a rigid support frame, base pads, a porous decoupling and absorption layer, and an auxiliary cavity, which together enhance vertical vibration decoupling, reinforcement, and acoustic insulation, optimizing low-frequency reproduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a simple decoupling frame with foam is used to mount the electrodynamic transducer, then the transducer is securely held in place, but low-frequency transmission is not optimized and insulation against rolling noise is insufficient
Solution Approach 1:
The patent implements a nested structure where the electrodynamic transducer is mounted on a vibrating plate, which is attached to a decoupling frame, which in turn is mounted on a support frame with multiple layers of damping materials (foam layer, viscoelastic layer, porous layer). Each layer is nested within the structural framework, creating a concentric arrangement of damping and decoupling elements that progressively isolate the transducer from vehicle vibrations while maintaining mounting stability.
Solution Approach 2:
The patent employs a composite damping structure consisting of multiple materials with different properties: an open-cell foam layer for initial decoupling, a viscoelastic layer for energy dissipation, and a porous layer for acoustic absorption. This composite arrangement combines the advantages of each material to achieve both secure mounting and effective noise insulation, particularly for low-frequency rolling noise.
2Reliability
If a rigid mounting structure is used to secure the transducer firmly, then mounting stability is improved, but vertical vibration decoupling is reduced and low-frequency reproduction is compromised
Solution Approach 1:
The decoupling frame exhibits spatially varying stiffness characteristics, with different rigidity in different directions and locations. The frame is designed to be more compliant in the vertical direction to allow vibration decoupling, while maintaining lateral stability through its geometric configuration and connection points. This local differentiation of mechanical properties enables simultaneous achievement of mounting stability and vibration isolation.
Solution Approach 2:
The patent utilizes materials and structures with specific mechanical parameter ranges: the foam layer has a Young's modulus between 10^4 and 10^6 Pa, the viscoelastic layer has a Young's modulus between 10^6 and 10^8 Pa, and the porous layer has a Young's modulus between 10^4 and 10^6 Pa. These controlled parameter variations enable the structure to provide adequate support while allowing necessary vertical compliance for vibration decoupling.
3Device complexity
If a compact mounting structure is used to save space, then device complexity is reduced, but acoustic insulation performance and low-frequency reproduction are degraded
Solution Approach 1:
The patent extends the damping and insulation functionality into the vertical dimension by creating a multi-layered structure with significant thickness in the direction perpendicular to the vibrating plate. The foam layer, viscoelastic layer, and porous layer are stacked vertically, creating a distributed insulation system that provides effective noise blocking without excessive lateral complexity. The support frame also creates vertical air gaps that contribute to acoustic insulation.
Solution Approach 2:
The patent introduces intermediate elements between the vibrating plate and the vehicle structure: the decoupling frame acts as an intermediary that mechanically decouples the transducer, while the multiple damping layers serve as intermediaries for acoustic insulation. These intermediary elements mediate between the transducer mounting requirements and the noise insulation requirements, providing a solution that addresses both functions without requiring a monolithic complex 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
The proposed architecture effectively decouples vertical vibrations, maintains the transducer in place, minimizes unwanted oscillations, and provides improved acoustic insulation against rolling noise, while enhancing low-frequency sound reproduction.
Implementation Method 1
a decoupling frame for said plate made of elastically compressible foam
Implementation Method 2
the decoupling frame exhibits increasing stiffness with distance from said plate; allows for vertical vibration decoupling of the plate
Implementation Method 3
a porous decoupling and absorption layer receiving said pads, said layer being elastically compressible and open-porous
Implementation Method 4
said layer being elastically compressible and open-porous, the Young's modulus of said layer being between 104 and 105 Pa
Implementation Method 5
an auxiliary cavity 11 extending around said studs and communicating with said main cavity via the inter-stud spaces 12, so as to define an extended cavity
Data Source
Figure 1
Figure 2
AI summary
The invention relates to a construction (1) for mounting an electrodynamic transducer in the passenger compartment of a motor vehicle, the construction comprising a plate (6) having a vibrating structure, at least one electrodynamic transducer (3) attached to the plate, a decoupling frame (4) of increasing stiffness, and a vehicle floor pan (2), and, between the decoupling frame and the floor pan: a rigid holding frame (7) that receives the decoupling frame; a plurality of feet (8) for the base of the holding frame, delimiting a main cavity (9); a porous decoupling and absorption layer (10); and an adjoining cavity (11) extending around the feet and communicating with the main cavity through the spaces (12) between the feet.