Piezoactuator Sound Transducer with Clamp Connection
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Solution Overview
Problem
Conventional sound transducers, particularly those used in ultrasonic sensors for vehicle driving assistance, face mechanical stability challenges due to exposure to flying debris, which can damage piezoactuators, and existing connection methods do not adequately secure the piezoactuator to the diaphragm, risking total failure.
Innovation Solution
A structurally advantageous connection is formed between the piezoactuator and lever elements using a clamp connection with axial pre-tension, allowing for a form-fitting or self-centering design that reduces the overall height and enhances mechanical stability by applying pre-tension to the piezoactuator, and optionally using a stacked piezoactuator configuration and damping mechanisms to prevent undesirable oscillations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the piezoactuator is connected directly to the diaphragm, then the connection is simple, but the mechanical stability is insufficient and the piezoactuator is vulnerable to damage from flying debris
Solution Approach 1:
The connection structure is segmented into multiple components: the piezoactuator, lever elements, and clamp connection. This segmentation allows the piezoactuator to be isolated from direct exposure to flying debris while maintaining a secure mechanical connection to the diaphragm through the lever elements, thereby improving reliability without excessive complexity
Solution Approach 2:
The lever elements serve as intermediary components between the piezoactuator and the diaphragm. These intermediaries transmit the oscillation forces while providing mechanical protection to the piezoactuator, allowing it to be clamped securely without direct exposure to external damage sources
2Reliability
If the piezoactuator is situated in parallel and at a distance to the diaphragm with lever elements, then the mechanical stability is improved, but the radial installation space is increased and the overall height is increased
Solution Approach 1:
The design utilizes the radial dimension efficiently by implementing a clamp connection that secures the piezoactuator in the radial direction. This allows the lever elements to be arranged in a compact radial configuration rather than requiring additional axial space, thereby maintaining mechanical stability while minimizing the overall radial installation footprint
3Ease of manufacture
If adhesive bonds are used to connect the lever element to the piezoactuator, then the connection is simple, but the connection strength is insufficient under oscillation forces
Solution Approach 1:
The adhesive bonding system is replaced with a mechanical clamp connection system. The clamp connection uses friction and normal forces generated by the clamping action to secure the lever element to the piezoactuator, providing significantly higher connection strength under oscillation forces while remaining manufacturable through standard mechanical assembly processes
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 improves the mechanical robustness and efficiency of the sound transducer by securely clamping the piezoactuator, reducing the device's height, and effectively damping unwanted oscillations, thereby enhancing its reliability and performance in harsh environments.
Implementation Method 1
The sound transducer is used as an emitter and/or receiver, an ultrasound pulse being emitted
Implementation Method 2
the piezoactuator is situated by the at least one lever element under axial pre-tension force
Implementation Method 3
the clamp connection includes a concave contact surface between the piezoactuator and the at least one lever element to form a self-centering clamp connection
Data Source
AI summary
A sound transducer, including a diaphragm and at least one piezoactuator, which is situated in an operative connection to the diaphragm, the oscillation direction of the piezoactuator being situated at least generally perpendicularly in relation to the oscillation direction of the diaphragm, at least one lever element being situated between the diaphragm and the piezoactuator, which connects the diaphragm to the piezoactuator and is designed to convert oscillations of the piezoactuator into oscillations of the diaphragm and vice versa, and a clamp connection being formed between the at least one lever element, and the piezoactuator. The clamp connection is formed between an end face of the piezoactuator situated in the oscillation direction of the piezoactuator and the at least one lever element, and the piezoactuator is situated under an axial pre-tension force extending in the oscillation direction of the piezoactuator by the at least one lever element.