Piezoelectric Washer Resistive Path for Accelerometer Reliability
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Solution Overview
Problem
Accelerometer sensors face issues with external electrical resistors breaking due to thermal stresses and the need for lead-free piezoelectric materials with stable electrical resistance, as existing solutions like nickel lugs are costly and PZT alternatives are expensive and temperature-sensitive.
Innovation Solution
Incorporating a resistive path on the outer contour of the ceramic body of the piezoelectric washer, which connects the conductive electrodes and is designed to maintain electrical resistance, eliminating the need for external attachment lugs and allowing for the use of alternative materials with temperature-dependent resistivity to stabilize electrical resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an external electrical resistor is used with metal attachment lugs, then the resistor can be connected to the piezoelectric washer, but the attachment lugs break due to thermal expansion stresses
Solution Approach 1:
The patent merges the external resistor into the piezoelectric washer by creating a resistive path directly within the ceramic body. The resistive path is formed by depositing resistive material on the outer contour of the ceramic body and connecting it to conductive electrodes, eliminating the need for separate attachment lugs and integrating the resistor function into the washer structure itself.
2Strength
If nickel lugs are used to strengthen attachment, then the attachment strength increases, but manufacturing cost increases and soldering becomes problematic
Solution Approach 1:
The patent extracts the attachment lug function entirely from the design. Instead of using nickel lugs or any separate attachment mechanism, the resistive path is directly integrated into the ceramic body of the piezoelectric washer, eliminating the need for soldering and complex attachment processes while reducing manufacturing cost.
3Reliability
If lead-free piezoelectric materials are used, then environmental compliance improves, but electrical resistance stability with temperature deteriorates
Solution Approach 1:
The patent introduces a resistive path as an intermediary element within the piezoelectric washer. This resistive path, formed by depositing resistive material on the outer contour of the ceramic body, compensates for the temperature sensitivity of lead-free piezoelectric materials by providing a stable resistive component that helps maintain overall electrical resistance stability across temperature variations.
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 solution enhances the robustness and functionality of the electrical resistance during thermal variations, reduces manufacturing costs, and allows for the use of lead-free materials, ensuring accurate acceleration measurements while protecting the resistor from detachment and thermal stress.
Implementation Method 1
a force exerted on the washer results in a change in the electric charge produced by the piezoelectric washer
Implementation Method 2
a resistive path connecting the conductive electrodes to one another with a length and cross section of the resistive path predetermined according to the resistance to be established between the two conductive electrodes
Data Source
AI summary
Disclosed is a piezoelectric washer intended for an accelerometer sensor having a ceramic body and a conductive electrode on each of two opposing faces, an electrical resistance being to be established between the two conductive electrodes. The ceramic body has, on its outer contour, a resistive path connecting the conductive electrodes to one another with a predetermined length and cross-section of the resistive path according to the resistance to be established between the two conductive electrodes.