Physical Quantity Sensor Shock Resistance via Elastic Damping
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Solution Overview
Problem
Existing acceleration sensors face challenges in achieving excellent shock resistance due to the risk of damage from excessive displacement and collisions between comb teeth-like movable and fixed electrodes, which limits their mechanical strength and detection accuracy.
Innovation Solution
The physical quantity sensor incorporates a restricting section with elastic properties and a specific configuration of outer edge portions to mitigate shock during contact, reduce excessive displacement, and prevent damage by ensuring surface contact and uniform hardness with the movable section, thereby enhancing shock resistance and detection accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a projecting section is provided in the comb tooth-like fixed electrode to limit the movable range, then shock resistance is improved, but the comb teeth-like movable electrode is highly likely to be damaged due to collision
Solution Approach 1:
The patent introduces a stopper section that contacts the movable electrode before excessive displacement occurs, and a damping section that absorbs shock energy. The damping section is positioned to receive impact from the movable electrode when it contacts the stopper section, cushioning the blow and preventing damage to the comb teeth-like movable electrode while maintaining the limiting function.
Solution Approach 2:
The patent introduces a damping section as an intermediary element between the movable electrode and the stopper section. This damping section acts as a mediator that absorbs and dissipates the impact energy when the movable electrode contacts the stopper, preventing direct transmission of shock forces that would damage the fragile comb teeth-like structure.
2Measurement precision
If the movable section is excessively displaced, then detection accuracy is maintained, but damage occurs to the movable section and restricting section
Solution Approach 1:
The damping section is pre-positioned to absorb shock energy before excessive displacement can cause damage. When the movable section approaches its limiting position, the damping section is activated to cushion the impact, protecting both the movable section and restricting section while allowing the sensor to maintain detection accuracy within its operational range.
Solution Approach 2:
The patent converts the harmful excessive displacement and collision forces into beneficial shock-absorbing actions through the damping section. The impact energy that would normally cause damage is instead absorbed and dissipated by the damping section, transforming a potentially harmful event into a protective mechanism that safeguards the sensor components.
3Reliability
If the restricting section is made rigid to effectively limit displacement, then shock resistance is improved, but the impact force during contact increases causing damage
Solution Approach 1:
The damping section serves as an intermediary between the rigid stopper section and the movable electrode. The stopper section maintains its rigid structure for effective displacement limiting, while the damping section absorbs the impact forces, preventing direct transmission of high impact forces to the movable electrode and reducing damage risk.
Solution Approach 2:
The rigid stopper section's limiting function is preserved while converting the harmful high impact forces into beneficial shock-absorbing actions through the damping section. The damping section dissipates the impact energy that would otherwise be transmitted to the fragile movable electrode, transforming a potentially damaging rigid contact into a protected interaction.
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 effectively reduces damage to the movable section and restricting section, improves shock resistance, and maintains detection accuracy by ensuring controlled contact and uniform mechanical strength, leading to a more reliable physical quantity sensor.
Implementation Method 1
the movable section and the restricting section come into contact, the movable section and the restricting section can be elastically deformed
Data Source
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AI summary
A physical quantity sensor includes a substrate, a fixed section fixed to the substrate, a movable section displaceable in a first direction with respect to the fixed section, a movable electrode section provided in the movable section, a fixed electrode section fixed to the substrate and disposed to be opposed to the movable electrode section in the first direction, and a restricting section configured to restrict a movable range in the first direction of the movable section. The movable section includes a first outer edge portion disposed on one side of the first direction and a second outer edge portion disposed on the other side. The restricting section includes at least one of a first restricting section disposed to be opposed to the first outer edge portion via a gap and a second restricting section disposed to be opposed to the second outer edge portion via a gap.