Structure-Borne Sound Actuator With Rigid Coupling Element
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Solution Overview
Problem
Current structure-borne sound actuators for motor vehicles require direct coupling to a sound body, which limits their effectiveness in sound radiation and efficiency, as they lack an intermediate element to influence frequency and volume of noise emitted.
Innovation Solution
Incorporating an acoustically rigid intermediate element between the excitation unit and the sound body, which is designed to enhance the transmission of excitation movement and adjust the frequency and volume of noise emitted, without direct contact between the excitation unit and the sound body, allowing for increased sound power transfer to the sound body.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If direct coupling between excitation unit and sound body is used, then stable attachment is achieved, but sound radiation effectiveness is limited
Solution Approach 1:
An intermediate element is introduced between the excitation unit and the sound body to serve as a mediator. This intermediate element has a first surface that couples to the excitation unit and a second surface that couples to the sound body, enabling improved sound radiation effectiveness while maintaining stable attachment through its structural design
2Productivity
If intermediate element is added to improve sound radiation, then sound power transfer is enhanced, but device complexity increases
Solution Approach 1:
The intermediate element is designed to perform multiple functions simultaneously: it provides stable attachment through its first surface coupling to the excitation unit, enables enhanced sound radiation through its second surface coupling to the sound body, and allows for frequency adjustment through its structural characteristics, thereby reducing the need for separate components
3Adaptability or versatility
If intermediate element is used to adjust frequency and volume, then sound quality is improved, but weight increases
Solution Approach 1:
The intermediate element's structural parameters such as geometry, material composition, and thickness are optimized to achieve the desired frequency and volume adjustment capabilities while minimizing weight. The element is designed with specific acoustic properties that allow frequency modulation without requiring heavy mass
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 design ensures that at least 95% of the sound power is emitted by the sound body, with minimal emission from the intermediate element, enabling more effective sound radiation and efficient use of space and weight, while allowing for precise adjustment of noise frequency and volume.
Implementation Method 1
Structure-borne sound actuators are used in the audio sector to acoustically excite surfaces using the bending wave principle. These actuators function similarly to conventional diaphragm speakers, as both are based on an electrodynamic transducer principle.
Implementation Method 2
The intermediate element is mounted between the excitation unit and the sound body in such a way that an excitation movement of the excitation unit can be transmitted to the intermediate element, and the excitation movement can be passed on from the intermediate element to the sound body.
Data Source
Figure 1~2
Figure 3~4
Figure 5
AI summary
The invention relates to a structure-borne sound actuator (2) for a motor vehicle (1), comprising an electrodynamic excitation unit (7). The excitation unit (7) is formed with an excitation side (10) designed to excite a sound body (4). An acoustically rigid intermediate element (3) is secured to the excitation side (10), and the intermediate element (3) has a coupling side (12) which faces away from the excitation side (10) and is designed to couple to the sound body (4).