Shear Mode Piezoelectric Accelerometer Torque Design

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Solution Overview

Problem

Conventional shear mode piezoelectric accelerometers require a large mass block to drive piezoelectric elements, resulting in increased volume, cost, and limited application due to the large size of the mass blocks compared to the piezoelectric elements.

Innovation Solution

A shear mode piezoelectric accelerometer design featuring a ring-shaped piezoelectric element, a central shaft, a mass block with a fixed element and a weight element, and electrodes connected to form a conduction circuit, allowing for deformation of the piezoelectric element and generation of a potential difference with a smaller mass block.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If a large mass block is used to drive the piezoelectric elements in shear mode, then the piezoelectric elements generate sufficient power, but the overall volume of the accelerometer increases significantly

Engineering Contradiction:

Improvepower generation of piezoelectric elementsVSAvoidoverall volume of accelerometer

Core Design Contradiction:

PowerVSVolume of moving object

Solution Approach 1:

The patent transitions from a conventional linear mass-block configuration to a ring-shaped piezoelectric element with the mass block positioned at the center. This dimensional rearrangement creates a torque-based shear force mechanism that generates sufficient power with a compact mass block, eliminating the need for large-volume mass blocks while maintaining power generation capability.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The patent employs a ring-shaped piezoelectric element instead of a conventional linear or block-shaped element. This curved geometry allows the mass block to be positioned at the center, creating a radial torque that generates shear force more efficiently. The curved structure optimizes the force distribution and lever arm, enabling compact design without sacrificing power generation.

Inventive Principle:

Principle #14Spheroidality (Curvature)

2Power

If a large mass block is used to drive the piezoelectric elements, then sufficient power is generated, but the cost and manufacturing complexity increase

Engineering Contradiction:

Improvepower generation of piezoelectric elementsVSAvoidmanufacturing cost and complexity

Core Design Contradiction:

PowerVSEase of manufacture

Solution Approach 1:

By reconfiguring the spatial arrangement from linear to ring-shaped with central mass block positioning, the patent achieves sufficient power generation with a compact design. This reduces material requirements and simplifies manufacturing processes, lowering overall cost while maintaining power generation performance.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The patent integrates the mass block and piezoelectric element into a unified torque-based shear force system. The mass block positioned at the center of the ring-shaped piezoelectric element creates a combined mechanism where the torque generated by the mass block directly drives the piezoelectric element, eliminating the need for separate large mass blocks and reducing manufacturing complexity.

Inventive Principle:

Principle #5Merging (Combining)

3Measurement precision

If the mass block is positioned far from the central shaft to increase torque, then detection sensitivity improves, but the overall device volume increases

Engineering Contradiction:

Improvedetection sensitivityVSAvoidoverall volume of accelerometer

Core Design Contradiction:

Measurement precisionVSVolume of moving object

Solution Approach 1:

The ring-shaped piezoelectric element creates a radial torque mechanism where the mass block positioned at the center generates maximum torque through the radial arm. This curved geometry optimizes the lever arm length within a compact volume, achieving high detection sensitivity without requiring the mass block to be positioned far from the central shaft, thus maintaining compact device dimensions.

Inventive Principle:

Principle #14Spheroidality (Curvature)

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 design reduces the overall volume and cost of the accelerometer, expands its application range, and enhances detection sensitivity by amplifying the shear force using torque and optimizing the mass block's center of gravity relative to the central shaft.

Implementation Method 1

the ring-shaped piezoelectric element is deformed and a potential difference is generated between the first electrode and the second electrode

Methodology Applied

Scientific EffectPiezoelectric effect: Piezoelectric Effect

Data Source

PatentUS20250035666A1Shear mode piezoelectric accelerometer

Publication Date: 2025.01.30 PIEZO ULTRATECH CO LTD

AI summary

A shear mode piezoelectric accelerometer includes a ring-shaped piezoelectric element, a central shaft, a mass block, a first electrode, and a second electrode. The ring-shaped piezoelectric element includes an outer ring wall and an inner ring wall. The central shaft is made of conductive material and is fixed through the inner ring wall of the ring-shaped piezoelectric element. The mass block is made of conductive material and includes a fixed element and a weight element. The fixed element has a fixed hole and is fixed to the outer ring wall of the ring-shaped piezoelectric element by fitting the fixed hole. The weight element is located on the fixed element on the opposite side away from the fixed hole. The first electrode is electrically connected to the central shaft. The second electrode is electrically connected to the mass block.