Acceleration Transducer with Segmented Piezoelectric Element
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing acceleration transducers face challenges in simultaneously detecting accelerations along multiple axes without interference, particularly in limited spaces, and require small dimensions and low weight for high-frequency measurements while maintaining accuracy.
Innovation Solution
The acceleration transducer design incorporates piezoelectric elements and seismic masses attached to a main body with tangential and normal side faces, utilizing electrically conductive coatings to eliminate interference charges and optimize space usage, allowing for detection in three dimensions with reduced components and weight.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If piezoelectric elements and seismic masses are attached to a main body with tangential and normal side faces, then detection capability in three dimensions is improved, but device complexity increases
Solution Approach 1:
The piezoelectric element is divided into multiple functional regions with different electrically conductive coatings applied to specific surfaces. The seismic mass is segmented into portions that can be independently positioned. This segmentation allows each component to perform multiple sensing functions simultaneously, enabling three-dimensional acceleration detection while managing device complexity through modular design.
Solution Approach 2:
The piezoelectric element is designed to serve multiple functions: detecting acceleration along the normal axis through its bulk piezoelectric effect, and detecting acceleration along tangential axes through shear stress on its surfaces. The seismic mass similarly contributes to both normal and tangential acceleration detection. This multi-functionality allows a single integrated structure to provide three-dimensional sensing capability without requiring separate sensors for each axis.
2Measurement precision
If electrically conductive coatings are applied to piezoelectric elements, then interference charges are eliminated, but manufacturing complexity increases
Solution Approach 1:
Electrically conductive coatings are applied selectively to specific surfaces of the piezoelectric element rather than uniformly across the entire surface. The coating is applied only to the tangential surfaces where shear stress occurs during tangential acceleration, leaving the normal surfaces uncoated. This localized application eliminates interference charges from shear-induced piezoelectric effects while maintaining ease of manufacture by reducing the total coated area and simplifying the coating process.
3Measurement precision
If the transverse shear effect is utilized for acceleration detection, then sensitivity to tangential acceleration is improved, but interference with normal acceleration detection occurs
Solution Approach 1:
The interference signal generated by the transverse shear effect is extracted and separated from the normal acceleration detection signal. Electrically conductive coatings are applied to collect and divert the piezoelectric charges generated by shear stress, preventing these charges from contaminating the measurement of normal acceleration. This extraction allows the transverse shear effect to be utilized for tangential acceleration sensing without interfering with normal acceleration detection.
Solution Approach 2:
Electrically conductive coatings serve as an intermediary between the piezoelectric element and the external circuitry. These coatings collect piezoelectric charges generated by shear stress and provide a dedicated path for these charges to be measured separately, preventing interference with the normal acceleration detection. The conductive coating acts as a mediator that isolates the shear-induced signals from the normal acceleration measurement channel.
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 configuration enables accurate detection of accelerations in multiple dimensions with minimized interference, achieving small size, low weight, and high-frequency capabilities while reducing production costs.
Implementation Method 1
movement of a seismic mass against a piezoelectric element lodged against a rigid main body generates electric charges
Data Source
AI summary
An acceleration transducer defines a rectangular coordinate system with two orthogonal horizontal axes that are both normal to a vertical axis and includes a main body disposed within a housing and defining tangential side faces arranged tangentially to the vertical axis, and a normal side face arranged normally to the vertical axis. A piezoelectric element is secured to one of the tangential side faces, and a seismic mass is secured to the piezoelectric element. A signal output is attached to the housing and includes a signal conductor spaced apart by an assembly gap from a tangential side face that is not attached to the piezoelectric element. The assembly gap extends perpendicularly to the vertical axis. The normal side face includes at least one main body output conductor spanning the assembly gap in a direction perpendicular to the vertical axis and directly contacting the signal conductor.