Piezoelectric Vibration Sensor with Integrated Temperature Detection

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Solution Overview

Problem

Existing vibration sensors require additional components, space, and wiring for temperature detection, which increases costs and complexity.

Innovation Solution

Integration of at least two piezoelectric elements made of different materials within the vibration sensor, allowing for temperature detection through capacitance measurement, enabling reliable operation across a wide temperature range without separate sensors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a separate temperature sensor is integrated into the drive unit, then temperature measurement is enabled, but device complexity, space requirements, and wiring increase

Engineering Contradiction:
Improvetemperature measurement capabilityVSAvoiddevice complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The piezoelectric actuator is designed to perform dual functions: mechanical excitation of the diaphragm and temperature sensing. By utilizing the inherent temperature dependence of the piezoelectric material's capacitance, the same component that generates mechanical vibrations also serves as the temperature sensor, eliminating the need for separate sensing elements and reducing overall device complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The temperature sensing function is merged with the piezoelectric actuator by using the actuator's capacitance characteristics for temperature detection. This combination integrates two previously separate functions (mechanical excitation and temperature sensing) into a single component, thereby reducing the number of parts, simplifying wiring, and decreasing space requirements.

Inventive Principle:
Principle #5Merging (Combining)

2Measurement precision

If piezoelectric elements made of different materials are used, then temperature detection capability is enabled, but manufacturing complexity increases

Engineering Contradiction:
Improvetemperature detection accuracyVSAvoidmanufacturing complexity
Core Design Contradiction:
Measurement precisionVSEase of manufacture

Solution Approach 1:

The invention exploits the temperature dependence of the piezoelectric material's capacitance parameter. By monitoring changes in capacitance values of the piezoelectric elements, temperature information is extracted without requiring additional sensing materials or complex manufacturing processes. The existing piezoelectric materials' inherent electrical characteristics are utilized for temperature detection.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If additional temperature sensor components are added, then temperature compensation for resonance frequency is enabled, but cost increases

Engineering Contradiction:
Improvetemperature compensation capabilityVSAvoidcomponent quantity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The piezoelectric actuator serves itself by providing both its primary function of mechanical excitation and the secondary function of temperature sensing. The capacitance measurements taken for monitoring the actuator's electrical characteristics also provide temperature information, allowing the component to 'self-diagnose' environmental conditions without requiring external sensing infrastructure.

Inventive Principle:
Principle #25Self-service

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

Enables accurate temperature determination and maintains sufficient mechanical excitation of the membrane across a large temperature range, reducing the need for additional sensors and wiring.

Implementation Method 1

a piezoelectric actuator for setting the diaphragm into vibration

Methodology Applied
Scientific EffectPiezoelectric effect: Piezoelectric Effect

Implementation Method 2

for detecting vibrations of the diaphragm

Methodology Applied
Scientific EffectPiezoelectric effect: Converse Piezoelectric Effect

Implementation Method 3

a temperature is determined by detecting a capacitance of at least one piezoelectric element

Methodology Applied
Scientific EffectCapacitance temperature dependence: Capacitance

Data Source

PatentEP3312574B1Vibration sensor with integrated temperature detection
Publication Date: 2022.07.13 VEGA GRIESHABER GMBH & CO
  • EP3312574B1 patent drawingFigure 1
  • EP3312574B1 patent drawingFigure 2~3
  • EP3312574B1 patent drawingFigure 4~5

AI summary

Vibration sensor with - a diaphragm that can be set into vibration, - a piezoelectric drive for setting the diaphragm into vibration and for detecting vibrations of the diaphragm, wherein the drive has at least two mechanically connected piezoelectric elements, a temperature sensor, wherein at least one first piezoelectric element is made of a first piezoelectric material and at least one second piezoelectric element is made of a second piezoelectric material.