Piezoelement Arrangement for Dynamic Torque Measurement
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Solution Overview
Problem
Existing measuring systems for determining torque and force on torque-transmitting shafts, particularly in motor development, face challenges with accuracy and calibration, especially when dealing with dynamic forces and require multiple piezoelements with specific orientations to accurately measure forces and torques without distortion.
Innovation Solution
A measuring system comprising at least three piezoelements with preferred directions oriented neither parallel nor antiparallel to each other, arranged around the rotational axis, allowing for the separation of measurement signals into linearly independent components to determine forces and torques, and a fixing device to support and position the piezoelements, enabling precise measurement without the need for additional piezoelement groups.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If strain gauges or piezoelectric sensors are used to measure torque on the shaft, then measurement capability is provided, but the reaction time is too long for measuring dynamic force paths
Solution Approach 1:
The patent extracts only the essential piezoelectric sensing function needed for dynamic measurement, removing unnecessary components like carrier plates and complex coordinate system orientations. By using piezoelements with preferred directions that lie parallel to or in a single plane intersected by the rotational axis, the system achieves both fast reaction time and adequate measurement precision for dynamic torque paths.
2Measurement precision
If multiple piezoelements with specific orientations are arranged around the rotational axis, then measurement accuracy is improved, but device complexity increases
Solution Approach 1:
The patent employs asymmetric arrangement of piezoelements where at least two preferred directions are oriented neither parallel nor antiparallel to each other, and preferably perpendicular. This asymmetric configuration allows accurate determination of both force components and torque while using fewer elements than traditional symmetric arrangements, thereby reducing device complexity while maintaining measurement precision.
Solution Approach 2:
The patent utilizes a three-dimensional spatial arrangement where piezoelement preferred directions lie parallel to or in a single plane intersected by the rotational axis. By leveraging spatial dimensionality and angular orientation rather than simply increasing the number of elements, the system achieves comprehensive measurement capability with reduced complexity.
3Ease of manufacture
If piezoelements are arranged with preferred directions parallel or antiparallel to each other, then installation is simplified, but measurement accuracy deteriorates due to force shunts
Solution Approach 1:
The patent deliberately avoids parallel or antiparallel orientations of piezoelement preferred directions, instead specifying that at least two preferred directions should be oriented neither parallel nor antiparallel, preferably perpendicular to each other. This asymmetric angular arrangement prevents force shunts and ensures accurate measurement of both force components and torque, while the orientations still lie in a single plane for manageable installation.
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 enhances measurement accuracy by minimizing force shunts and allowing for the precise determination of dynamic forces and torques, including those contributing to shaft wobbling, without distorting the measurement results or altering the rotating mass of the shaft.
Implementation Method 1
piezoelectric measuring elements, or piezoelements respectively, are suited to measuring dynamic tensile, compressive and shear forces
Data Source
AI summary
The invention relates to a measuring system for determining a force and/or a torque on a torque-transmitting shaft, wherein: the measuring system has at least three, in particular at least four, piezoelectric elements each having a preferred direction and each being arranged at different positions about a rotational axis of the shaft in a force flow transmitted via the shaft, said arrangement being such that a force of the force flow acts, in particular exclusively, on the piezoelectric elements; the preferred directions each lie parallel to or in a single plane which is intersected by the rotational axis; and the preferred directions of at least two, in particular at least three, of the piezoelectric elements are oriented neither parallel nor antiparallel to one other.