A torque sensor, torque transducer or torque meter is a device for measuring and recording the torque on a rotating system, including an engine, crankshaft, gearbox, transmission, rotor, a bicycle crank or Compression Load Cell. Static torque is fairly very easy to measure. Dynamic torque, however, can be difficult to measure, as it generally requires transfer of some effect (electric, hydraulic or magnetic) from the shaft being measured to a static system.
One way to accomplish this would be to condition the shaft or perhaps a member attached to the shaft with several permanent magnetic domains. The magnetic characteristics of such domains can vary in accordance with the applied torque, and therefore can be measured using non-contact sensors. Such magnetoelastic torque sensors are usually employed for in-vehicle applications on racecars, automobiles, aircraft, and hovercraft.
Commonly, torque sensors or torque transducers use strain gauges put on a rotating shaft or axle. Using this method, a means to power the strain gauge bridge is important, as well as a methods to get the signal from your rotating shaft. This can be accomplished using slip rings, wireless telemetry, or rotary transformers. Newer varieties of torque transducers add conditioning electronics plus an A/D converter for the rotating shaft. Stator electronics then look at the digital signals and convert those signals to your high-level analog output signal, like /-10VDC.
A far more recent development is the usage of SAW devices attached to the shaft and remotely interrogated. The strain on these tiny devices since the shaft flexes could be read remotely and output without resorting to attached electronics on the shaft. The probable first use in volume will be in the automotive field as, of May 2009, Schott announced it features a SAW sensor package viable for in vehicle uses.
Another way to measure Rotary Torque Sensor is through twist angle measurement or phase shift measurement, whereby the angle of twist as a result of applied torque is measured by utilizing two angular position sensors and measuring the phase angle between the two. This method can be used inside the Allison T56 turboprop engine.
Finally, (as described inside the abstract for US Patent 5257535), in the event the mechanical system involves a right angle gearbox, then this axial reaction force experienced by the inputting shaft/pinion can be linked to the torque experienced by the output shaft(s). The axial input stress must first be calibrated from the output torque. The input stress can be easily measured wbtbtc strain gauge measurement of the input pinion bearing housing. The output torque is definitely measured utilizing a static torque meter.
The torque sensor can function just like a mechanical fuse and is also a vital component to get accurate measurements. However, improper setting up the torque sensor can damage the device permanently, costing money and time. Hence, the torque sensor has to be properly installed to make sure better performance and longevity.
The performance and longevity in the Multi Axis Load Cell and its reading accuracy is going to be affected by the design in the driveline. The shaft becomes unstable at the critical speed in the driveline to result in torsional vibration, which can harm the torque sensor. It is required to direct the strain to an exact point for accurate torque measurement. This point is typically the weakest reason for the sensor structure. Hence, the torque sensor is purposely designed to be one from the weaker elements of the driveline.