Rotational Torque Measurement Using Magnetic Rings
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Solution Overview
Problem
Current methods for measuring torque on rotating components face challenges such as fragility of strain gages, limitations in slip ring technology, and incompatibility with high-speed applications, as well as issues with optical and magnetic signature methods, particularly in environments with contamination and movement constraints.
Innovation Solution
A non-contact torque measurement system using magnetic rings and sensing coils with corresponding electronics and software to analyze phase differences in waveforms generated by rotating magnetic rings, allowing for accurate torque measurement with significant liftoff and minimal interference, applicable to rotating equipment and other stressed objects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If strain gage elements are used to measure torque, then torque measurement capability is achieved, but the device becomes fragile and susceptible to permanent shift or complete failure
Solution Approach 1:
The patent replaces traditional mechanical strain gage elements with a magnetic field-based measurement system. Magnetic rings with embedded magnets generate magnetic field signatures that are detected by sensors, eliminating the need for physical strain gages that are prone to failure. This substitution of mechanical sensing with magnetic field detection resolves the fragility issue while maintaining torque measurement precision.
Solution Approach 2:
The patent introduces magnetic rings as an intermediary component between the rotating shaft and the measurement system. These rings carry magnets that create magnetic field signatures proportional to shaft torque, serving as a mediator that transfers mechanical torque information to the magnetic field domain for non-contact detection, thereby improving reliability.
2Measurement precision
If slip rings are used to transmit power and signals to rotating components, then real-time measurement is achieved, but vibration, contact wear, contamination and heat generation occur
Solution Approach 1:
The patent replaces mechanical slip ring contact systems with non-contact magnetic field sensing. The magnetic rings rotate with the shaft while stationary sensors detect the magnetic field signatures through the housing, eliminating mechanical contact entirely. This substitution eliminates vibration, contact wear, contamination, and heat generation associated with slip rings while maintaining real-time measurement capability.
3Reliability
If optical type systems are used for torque measurement, then non-contact measurement is achieved, but the system becomes expensive and intolerant to optical contamination
Solution Approach 1:
The patent substitutes optical measurement systems with magnetic field-based measurement. Instead of using light that can be obscured by dust and dirt, the system uses magnetic fields that penetrate contaminants without degradation. Magnetic rings with magnets generate field signatures detected by sensors through the housing, providing robust non-contact measurement that is insensitive to optical contamination.
4Measurement precision
If magnetic signature modeling requires substitution of prime components with exotic materials, then torque measurement capability is improved, but manufacturing complexity and certification issues increase
Solution Approach 1:
The patent creates a universal measurement system that can be applied to existing shafts without requiring substitution of prime components with exotic materials. The magnetic rings are separate add-on components that can be installed on conventional shafts, and the measurement system works with standard manufacturing processes, reducing complexity and certification requirements.
Solution Approach 2:
The patent divides the measurement system into separate modular components: magnetic rings that can be independently manufactured and installed on existing shafts, and stationary sensor assemblies. This segmentation allows the measurement functionality to be added without redesigning or replacing the entire shaft assembly, simplifying manufacturing and certification.
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 and reliable torque measurement with negligible impact on dynamic balance, tolerant to relative movement and contamination, and suitable for high-speed applications without physical modification of the component, improving performance and safety in various industrial and transportation settings.
Implementation Method 1
The system includes a housing (100) having an interior cavity (102). A shaft (110) is rotatable within the cavity (102) of the housing (100). A magnetic ring (120) is coupled to the shaft (110). The magnetic ring (120) includes a plurality of magnets (122). A sensor assembly (130) is mounted to the housing (100) and includes a sensor (132). The sensor (132) is positioned within the cavity (102) and is spaced from the magnetic ring (120) by a distance. The sensor (132) detects a magnetic field signature from the magnets (122) of the magnetic ring (120).
Data Source
AI summary
A system and method for measuring torque on a rotating component, comprising of signal-producing components which are applied to the rotating component, and a means for obtaining the signals produced by said signal producing components, in which at least two signal producing components are applied to the rotating component with some linear separation between the two signal producing components and their corresponding devices for obtaining signals produced, such that torque applied to the rotating component will cause a change in phase between the signals received from each of the signal-producing components and thus permit the measurement of torque based on this change in phase; one embodiment of this invention comprising two magnetic rings, one at either end of a driveshaft, with sensor coils placed near to each magnetic ring such that an alternating electrical current is produced, the comparative phase between these currents permitting measurement of torque on the driveshaft.