TECHNICAL FIELD

The disclosure relates generally to mechanical components, such as rotating components, used in machines, and more particularly, to measuring torque and other parameters of the mechanical components without the measuring devices having physical connections to the mechanical components or requiring direct modifications of the mechanical components.

BACKGROUND ART

Measurement of torque and other related parameters are useful capabilities in a number of transportation and industrial applications. For example, measuring the torque or strain on a mechanical element such as a rotating component (e.g., a drive shaft) can be used in Health and Usage Monitoring Systems (HUMS) to determine the use of the component and the available or expected lifetime of the component. Additionally, the measurement of torque in real-time enables the HUMS to warn when the rotating component is approaching a limit of operation.

There are many approaches for measuring and monitoring torque, from the simple to the more complex, and under less arduous applications they can all provide reliable results. For example, basic methods of measuring and monitoring torque typically center around the use of strain gage elements with required power supply/signal connections and strategic placement of the strain gage elements on a targeted member or serially loaded component elements associated with the member. Although useful in many instances, there are inherent limitations and application challenges associated with the use of strain gauges. For instance, use of traditional strain gages requires surface preparation and adherence methods that can sometimes alter or constrain the gages or their assembled version. In addition, these strain gages tend to be fragile devices that can be over-stressed with a hysteresis affect causing a permanent shift to the strain gage characteristics. This can affect calibration values of the strain gauges or can result in complete device failure.

Measuring and monitoring torque of mechanical elements that include rotating components present further challenges due to the rotational motion associated with the rotating components, which can include axial and non-concentric radial movement of the components relative to surrounding housings and sensor assemblies. For example, obtaining torque measurements from a rotating component often entails successful coupling of power from the torque measuring instrumentation to the targeted rotating component and retrieval of signal data generated on the component, all while not adversely altering its functional use. The use of slip rings is one of the early principal approaches deployed to couple torque measuring instrumentation to targeted rotating components. However, slip rings are susceptible to vibration, contact wear, contamination and heat generation from contact friction with the rotating components.

A wireless variant of slip rings addressed some of the vulnerability issues associated with such devices by utilizing inductive coupling of power and signals from the rotating component (e.g., the inductive coupling of power and signals from a housing to a drive shaft). However, these wireless variants still share some of the burdens of the closely related slip rings. Some of these burdens include a physical limitation to tolerated movement of the monitored rotating components to surrounding housing/coupling mechanics of the wireless slip ring/sensor pickup assemblies, and the use of bearings to support the assemblies around the rotating components (e.g., shaft-like elements) that are substituted for a length of the monitored components. Further, these wireless variants of slip rings can have a large space allocation requirement and can add to frictional losses along with rotational speed limit specifications that can constrain their application.

Another approach to measuring and monitoring torque involves using optical type sensor systems. Typically, optical type sensor systems do not necessitate modifications to the rotating components in order to be operational. However, these systems tend to be expensive and not tolerant to optical contamination that can arise from many possible sources in their normal operating environment. For example, dust particles and dirt may obscure the markings, objects, or emitters used by the optical sensors. The dust particles and dirt can also cover and/or degrade the performance of the sensing elements themselves. Further, optical type sensor systems are not well suited for use in locations where oils or other commonplace contaminants are present, as these items obscure the optical performance.

Another approach to measuring and monitoring torque involves utilizing non-contact magnetic field measurement. One example of non-contact magnetic field measurement relies on the use of magnetic signature modeling to measure torque. However, this approach requires substitution of prime components with parts constructed of exotic materials and extensive instrumentation. Further drawbacks to using magnetic signature modeling to measure torque are that this approach typically involves new processes, significant engineering time for design and calculations, potential certification issues, and practical use limitations of material characteristics to perform the intended task of measuring and monitoring torque in a rotating component. These issues become even more significant when the rotating component is part of an established system and manufacturing process. For example, consider a widely-used vehicle such as an automobile. Any change to an established design of components of the vehicle impacts the physical manufacturing and also the vehicle safety and certification areas of the car industry.

Other non-contact magnetic field measurement approaches to ascertaining torque in rotating components have common challenges. For example, most methods for non-contact magnetic field measurements tend to be limited by very small “lift-off” levels (i.e., small fractions of an inch). In many cases, in order to be properly instrumented, a rotating component such as a shaft, may require one quarter of an inch or greater clearance due to its movement while in use. This amount is typically much greater than the practical ranges for many magnetic field measurement-based devices.

SUMMARY OF THE INVENTION

This summary of the invention introduces a selection of certain concepts in a brief form that are further described below in the detailed description. It is not intended to exclusively identify key features or essential features of the claimed subject matter set forth in the claims, nor is it intended as an aid in determining the scope of the claimed subject matter.

Aspects of the present invention are directed to a solution for addressing one or more of the limitations associated with the previously described approaches to measuring and monitoring torque in a mechanical component, such as a rotating component. To this extent, embodiments of the present invention are directed to a new and innovative approach to measuring and monitoring torque of a rotating component. Other related parameters of the rotating component, such as for example, strain (e.g., twist), rotational speed, rotational displacement, spatial displacement, etc., also can be measured and monitored. The embodiments require neither physical connections to the measured rotating component nor direct modifications of the rotating component, and are not limited to very small lift-off levels. Furthermore, the embodiments can utilize a robust characterization method to measure and monitor torque and related parameters of a rotating component that is tolerant to relative movement, and has minimum interference clearance that can be attached to high speed rotating parts with negligible impact to dynamic balance of the rotating parts.

In addition, the approach afforded by the embodiments is wireless and enables accurate acquisition of data with no moving components except for the rotating component itself. Furthermore, the embodiments of the present invention have applicability beyond rotating components. In particular, the embodiments are suited for use with any mechanical components that can become stressed and move during intervals of operation, and where it is desirable to measure and monitor torque of these components for performance, structural and safety reasons.

A first aspect of the invention provides a system for measuring torque of a mechanical component, comprising: at least two bands affixed to the mechanical component; at least two sensing assemblies operatively coupled to each band, each sensing assembly configured to generate signals indicative of relative movement between a respective band and the sensing assembly; a signal conditioner to condition the signals; and a computing unit to determine a torque applied to the mechanical component based on the conditioned signals, wherein the computing unit is configured to determine the torque by: determining a radial displacement of the mechanical component with the bands based on strength and phase differences of the signals obtained by the respective sensing assemblies operatively coupled to the bands; determining an angular offset of the bands with the rotating component due to the radial displacement; determining an apparent angular phase difference between the bands based on differences in the signals generated from respective sensing assemblies; determining the amount of twist of the mechanical component that is present while the mechanical component is experiencing torque as a function of the apparent angular phase difference, the angular offset, and a predetermined angular phase difference between the bands obtained under a known torque condition; and correlating the amount of twist with the torque applied to the mechanical component.

A second aspect of the invention provides a system for measuring torque of a rotating component, comprising: at least two bands affixed to the rotating component with a predetermining spacing separating the bands; at least two sensing assemblies operatively coupled to each band, each sensing assembly configured to generate signals that are indicative of a change in magnetic flux due to relative movement between a respective band and the sensing assembly; a signal conditioner with a pre-processing component to condition and pre-process the signals generated by the sensing assemblies; a computing unit to determine the torque applied to the rotating component based on the conditioned and pre-processed signals, wherein the computing unit is configured to determine the torque by: determining a radial displacement of an axis of rotation of the rotating component with the bands based on a strength and phase differences of the signals obtained by the respective sensing assemblies operatively coupled to the bands; determining an angular offset of the bands with the axis of rotation of the rotating component due to the radial displacement; determining an apparent angular phase difference between the bands based on differences in the signals generated from respective sensing coils assemblies; determining an amount of twist as a function of the apparent angular phase difference, the angular offset, and a predetermined angular phase difference between the magnetic bands obtained under a known torque condition; and correlating the amount of twist with the torque applied to the rotating component.

A third aspect of the invention provides a system for measuring torque of a rotating component, comprising: at least two bands affixed to the rotating component; at least two sensing assemblies operatively coupled to each band, each sensing assembly configured to generate signals indicative of movement of a respective band operatively coupled to the sensing assembly; a signal conditioner to condition the signals, wherein the signal conditioner is configured to filter the signals, and identify feature events in the filtered signals; and a computing unit configured to determine the torque applied to the rotating component by: identifying feature events in the filtered signals associated with each sensing assembly; recording a feature event timestamp in response to the identification of each feature event; determining a radial displacement of the rotating component with the bands based on timing differences of the feature events identified for the respective sensing assemblies operatively coupled to the bands; determining an angular offset of the bands with the rotating component due to the radial displacement; determining an apparent angular phase difference between the bands based on differences in the signals generated from respective sensing assemblies; determining the amount of twist as a function of the apparent angular phase difference, the angular offset, and a predetermined angular phase difference between the bands obtained under a known torque condition; and correlating the amount of twist with the torque applied to the rotating component.

A fourth aspect of the invention provides a system for monitoring torque of a rotating component, comprising: at least two bands affixed to the rotating component; at least two sensing assemblies operatively coupled to each band, each sensing assembly configured to generate signals indicative of movement of a respective band operatively coupled to the sensing assembly; a signal conditioner to condition the signals; a computing unit to determine the torque applied to the rotating component based on the conditioned signals, wherein the computing unit is configured to determine the torque from an amount of twist of the rotating component that is induced by the torque, wherein the computing unit determines a radial displacement of the axis of rotation of the rotating component with the bands based on a strength and phase differences of the signals obtained by the respective sensing assemblies operatively coupled to the bands, wherein the computing unit determines an angular offset of the bands with the axis of rotation of the rotating component due to the radial displacement, wherein the computing unit determines an apparent angular phase difference between the bands based on differences in the signals generated from respective sensing assemblies, and wherein the computing unit is configured to determine the amount of twist as a function of the apparent angular phase difference, the angular offset, and a predetermined angular phase difference between the bands obtained under a known torque condition; and a data acquisition unit operatively coupled to the computing unit, wherein the data acquisition unit is configured to monitor the torque and the twist determined by the computing unit and determine an effect that the torque and the twist has on the rotating component.

Other aspects of the invention provide methods, systems, program products, and methods of using and generating each, which include and/or implement some or all of the actions described herein. The illustrative aspects of the invention are designed to solve one or more of the problems herein described and/or one or more other problems not discussed.

