Micromechanical Spiral Spring Damping for Interference Modes
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Solution Overview
Problem
Micromechanical inertial sensors with meandering-folded spiral springs face interference modes due to undesirable oscillations, which can lead to sensor malfunction if not adequately damped, especially when resonant frequencies coincide with voltage or force pulses from the evaluation circuit.
Innovation Solution
Incorporating damping devices, such as structures that increase air resistance or perforation holes, at the connecting bars of the spiral spring folding sections to reduce natural oscillations and interference modes, while maintaining the seismic mass's oscillation unaffected.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If long spiral springs are used to achieve soft suspension and great deflection, then the deflection capability is improved, but interference modes occur due to oscillating folding sections
Solution Approach 1:
The harmful oscillating folding sections are extracted and detached from the main spring function by introducing damping devices that isolate their interference modes from the sensor's measurement frequency range, allowing long springs to be used without compromising reliability
Solution Approach 2:
The damping characteristics of the spiral spring system are changed by adding damping devices that modify the oscillation behavior of folding sections, shifting their resonant frequencies away from the sensor's operating frequency and eliminating interference
2Volume of moving object
If meandering-folded spiral springs are used to install long springs compactly, then the compactness is improved, but folding sections act as deflectable oscillating masses causing interference
Solution Approach 1:
The harmful oscillating folding sections are converted into beneficial damping elements by introducing damping devices that exploit their oscillation to provide damping forces, transforming the interference source into a useful vibration suppression mechanism
Solution Approach 2:
Damping devices are introduced as intermediary elements between the folding sections and the surrounding environment, mediating the oscillation energy and dissipating it through air resistance and friction, thereby preventing interference while maintaining compact folding structure
3Reliability
If damping devices are added to reduce interference modes, then the interference damping is improved, but the device complexity increases
Solution Approach 1:
The damping devices are designed to serve multiple functions simultaneously: they provide interference mode damping, maintain structural support for the folding sections, and are integrated into the existing spring geometry, reducing the need for separate components and simplifying the overall device
Solution Approach 2:
The damping function is merged with the existing spring structure by integrating damping devices directly into the folding sections, combining the suspension function and damping function into a unified structure rather than adding separate independent components
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 damping devices effectively reduce interference mode amplitudes, preventing the spiral spring ends from hitting the substrate, thus enhancing the signal/noise ratio and extending the application range of micromechanical sensors and actuators by minimizing noise levels and improving precision.
Implementation Method 1
the damping device includes at least one damping structure which increases the air resistance of the connecting bar in the deflection direction
Implementation Method 2
the friction effects achieved between the gas molecules and the side walls of a perforation hole are the greater the greater the ratio between the perimeter of a perforation hole and its base area is
Data Source
AI summary
A micromechanical component including a mass structure which may be deflected with respect to a substrate with the aid of at least one spiral spring in a direction of deflection. The spiral spring includes at least one folding section, which is formed by two spring legs which are situated essentially in parallel to each other and are connected to each other with the aid of a connecting bar. A damping device for oscillating movements of the folding section in the direction of deflection is provided in the area of the connecting bar.