Buffered Vibration Sensor Assembly for Low-Frequency Sensitivity
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Solution Overview
Problem
Vibration sensors with small sensing cavities face sensitivity issues due to potential diaphragm collisions with other components during large amplitude vibrations, leading to damage and reduced reliability.
Innovation Solution
Incorporating a vibration assembly with a mass element and elastic element, a buffer to limit vibration amplitude, and adjusting resonance frequencies to enhance sensitivity and prevent collisions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the sensing cavity volume is reduced to improve sensitivity, then sensitivity is improved, but the risk of diaphragm collision with other components increases during large amplitude vibrations
Solution Approach 1:
The patent introduces a buffer structure positioned between the diaphragm and other components (substrate, housing) to provide cushioning protection before collision can occur. This buffer absorbs excess vibration energy and prevents direct contact between the diaphragm and hard surfaces, thereby resolving the contradiction by allowing small sensing cavity volume (for high sensitivity) while preventing diaphragm damage during large amplitude vibrations.
2Measurement precision
If the sensing cavity volume is reduced to improve sensitivity, then sensitivity is improved, but the maximum vibration amplitude is constrained
Solution Approach 1:
The buffer structure is positioned in advance to accommodate and limit excessive vibration amplitudes. When the diaphragm vibrates with large amplitude, the buffer engages to prevent the diaphragm from traveling beyond a safe displacement, thereby maintaining high sensitivity through small cavity volume while constraining maximum vibration amplitude to prevent damage.
Solution Approach 2:
The patent changes the physical state or properties of the buffer material to provide non-linear resistance that increases with vibration amplitude. This allows the system to maintain high sensitivity for normal vibrations while automatically limiting maximum amplitude through the buffer's progressive resistance, effectively decoupling sensitivity from vibration amplitude constraints.
3Reliability
If the buffer distance is increased to prevent diaphragm collision, then reliability is improved, but the sensitivity is reduced
Solution Approach 1:
The buffer is designed to provide only partial cushioning action - it engages only when vibration amplitudes exceed a certain threshold. For normal operating conditions, the buffer remains inactive, allowing the diaphragm to vibrate freely with maximum sensitivity. Only when excessive vibration occurs does the buffer engage to prevent collision, thus providing reliability without compromising normal sensitivity performance.
Solution Approach 2:
The buffer is positioned at an optimized distance that provides beforehand cushioning only when needed. This distance is carefully designed to be small enough to maintain high sensitivity for normal vibrations, yet sufficient to prevent collision during extreme vibrations. The buffer's strategic positioning ensures it provides protection in advance without creating excessive spacing that would reduce sensitivity.
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 sensitivity in low-frequency bands and prevents diaphragm collisions, enhancing the reliability and durability of the vibration sensor.
Implementation Method 1
an acoustic transducer in communication with the first acoustic cavity, the acoustic transducer generating an electrical signal in response to a volume change of the first acoustic cavity
Implementation Method 2
the vibration assembly vibrating to make a volume of the first acoustic cavity change in response to an external vibration signal
Implementation Method 3
a buffer that limits a vibration amplitude of the vibration assembly
Data Source
AI summary
Vibration sensors are provided. The vibration sensor may include: a vibration assembly, the vibration assembly including a mass element and an elastic element, and the mass element being connected to the elastic element; a first acoustic cavity, the elastic element constituting one of sidewalls of the first acoustic cavity, and the vibration assembly vibrating to make a volume of the first acoustic cavity change in response to an external vibration signal; an acoustic transducer, the acoustic transducer being in communication with the first acoustic cavity and the acoustic transducer generating an electrical signal in response to a volume change of the first acoustic cavity; and a buffer, the buffer limiting a vibration amplitude of the vibration assembly, wherein the acoustic transducer has a first resonance frequency, the vibration assembly has a second resonance frequency, and the second resonance frequency of the vibration assembly is smaller than the first resonance frequency.