Wireless torque sensor prevails
4 Jun 2013
An innovative TorqSense wireless torque sensor from Sensor Technology provided an effective solution to an engineering challenge.
Advanced Design Innovations (ADI) was asked by Bristan to develop a durability test rig to help optimise product performance.
Until recently, the company carried out these tests by continuously operating the taps and controls using a pneumatically operated test rig with fixed stop positions for the rotary motion.
This arrangement was not entirely satisfactory, however, as it made little allowance for any increase in operating torque that occurred during testing and it could not accommodate the effects of wear in, for example, the rubber washers used in taps.
After carefully analysing the application requirements, ADI proposed a completely new test rig, which would be driven by servomotors rather than pneumatic cylinders, as this would allow much more accurate and consistent control to be achieved.
Preliminary investigations revealed that typical torque sensors were far too bulky to accommodate in a reasonably sized test rig, and also that they were incapable of delivering accurate results over the range required – from 1.5 Nm to 3.0 Nm.
After further research, however, ADI discovered the innovative TorqSense range of sensors from Sensor Technology. “These versatile sensors were exactly what we needed,” stated Jeff Lowe of ADI.
The TorqSense units are a new type of sensor based on patented technology that makes use of surface acoustic wave transducers.
These transducers comprise two thin metal electrodes, in the form of interlocking “fingers”, on a piezoelectric substrate such as quartz.
When an RF signal of the correct frequency is applied to the transducer, surface acoustic waves are set up, and the transducer behaves as a resonant circuit.
Since the transducers operate at radio frequencies, it is easy to couple signals to them wirelessly.
Hence, TorqSense sensors that incorporate the SAW transducer technology can be used on rotating shafts, and can provide data continuously without the need for the inherently unreliable brushes and slip rings that are often found in traditional torque measurement systems.
For more information, please contact: +44 (0)1869 238400 or visit www.sensors.co.uk. Alternatively, E-mail: webinfo@sensors.co.uk.
