Vibratory Sensor Resonator Shock Resistance

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Solution Overview

Problem

Conventional vibratory sensors using piezoelectric resonator elements face challenges in detecting acceleration with high precision due to vibration leakage, which reduces resonance frequency accuracy and can lead to damage from concentrated stress during shocks, especially when the resonator elements have short narrowed portions.

Innovation Solution

The design incorporates resonator elements with extended narrow portions and support structures, where the length ratio of narrow portions to base portions ranges from 50% to 200%, preventing stress concentration and enhancing shock resistance, while maintaining high vibration efficiency and precision through strategically placed support and connection configurations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If the narrow portions are made short to reduce device size, then the resonator element becomes more compact, but stress concentrates on the narrow portions causing damage during shocks

Engineering Contradiction:

Improveresonator element sizeVSAvoidshock resistance

Core Design Contradiction:

Volume of moving objectVSStrength

Solution Approach 1:

The patent changes the geometric parameters of the narrow portions, specifically setting the length ratio of narrow portion to base portion between 0.3 and 0.7, and the width ratio between 0.5 and 0.8. These parameter optimizations allow the narrow portions to be sufficiently long to distribute stress during shocks while maintaining a compact overall resonator element size.

Inventive Principle:

Principle #35Parameter changes

2Strength

If the narrow portions are made long to improve shock resistance, then stress distribution improves, but vibration leakage increases reducing detection precision

Engineering Contradiction:

Improveshock resistanceVSAvoidacceleration detection precision

Core Design Contradiction:

StrengthVSMeasurement precision

Solution Approach 1:

The patent optimizes the length ratio of narrow portions to base portions within the range of 0.3 to 0.7, and width ratio within 0.5 to 0.8. These specific parameter ranges create a balance where the narrow portions are long enough to distribute stress during shocks but not so long that they excessively transmit vibration to the base portions, thereby maintaining acceleration detection precision.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent applies different dimensional characteristics to different parts of the resonator element. The narrow portions have reduced width compared to base portions, creating a gradient structure that locally modifies vibration transmission properties while maintaining overall structural integrity and shock resistance.

Inventive Principle:

Principle #3Local quality

3Measurement precision

If the resonating arm length is increased to improve detection sensitivity, then detection sensitivity increases, but vibration leakage to base portions increases reducing Q value

Engineering Contradiction:

Improvedetection sensitivityVSAvoidQ value

Core Design Contradiction:

Measurement precisionVSLoss of energy

Solution Approach 1:

The patent introduces narrow portions with reduced dimensions at specific locations between the resonating arms and base portions. This local structural modification creates a vibration isolation effect that prevents vibration from long resonating arms from leaking to the base portions, thereby maintaining high Q values while allowing long resonating arms for high detection sensitivity.

Inventive Principle:

Principle #3Local quality

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 significantly enhances the shock resistance and detection precision of vibratory sensors by distributing stress evenly and minimizing vibration leakage, allowing for reliable and accurate acceleration detection without damaging the resonator elements.

Implementation Method 1

The vibratory sensor detects a magnitude of the force by detecting a change in the resonance frequency of a piezoelectric resonator element occurring due to the force exerted by the acceleration or the like

Methodology Applied

Scientific EffectPiezoelectric effect: Piezoelectric Effect

Implementation Method 2

detecting a change in the resonance frequency of a piezoelectric resonator element

Methodology Applied

Scientific EffectResonance: Resonance

Data Source

PatentUS8100016B2Vibratory sensor

Publication Date: 2012.01.24 SEIKO EPSON CORP

AI summary

A vibratory sensor includes a resonator element including (i) a first base portion and a second base portion, each ot the first and the second base portions having an upper main surface and a lower main surface, (ii) a resonating arm extended in a beam shape between the first and the second base portions to be vibrated at a predetermined resonance frequency, (iii) a first narrow portion formed by reducing a width of a portion extended from the first base portion to be smaller than a width of the first base portion in a direction orthogonal to an extending direction of the resonating arm, (iv) a second narrow portion formed by reducing a width of a portion extended from the second base portion to be smaller than a width of the second base portion in the direction orthogonal to the extending direction of the resonating arm, (v) a first support portion extended from the first narrow portion in a direction opposite to the first base portion, and (vi) a second support portion extended from the second narrow portion in a direction opposite to the second base portion.