A torque sensor, torque transducer or torque meter is a device for measuring and recording the torque on a rotating system, like an engine, crankshaft, gearbox, transmission, rotor, a bicycle crank or torque transducer. Static torque is comparatively easy to measure. Dynamic torque, on the other hand, can be difficult to measure, because it generally requires transfer of some effect (electric, hydraulic or magnetic) from the shaft being measured to a static system.
A good 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 these domains can vary according to the applied torque, and therefore could be measured using non-contact sensors. Such magnetoelastic torque sensors are usually utilized 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. With this method, a method to power the strain gauge bridge is necessary, and also a means to have the signal from your rotating shaft. This can be accomplished using slip rings, wireless telemetry, or rotary transformers. Newer kinds 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 a high-level analog output signal, like /-10VDC.
A much more recent development is the usage of SAW devices connected to the shaft and remotely interrogated. The strain on these tiny devices since the shaft flexes may be read remotely and output without resorting to attached electronics on the shaft. The probable first use in volume are usually in the automotive field as, of May 2009, Schott announced it possesses a SAW sensor package viable for in vehicle uses.
An additional way to 3 axis load cell is through twist angle measurement or phase shift measurement, whereby the angle of twist resulting from applied torque is measured by using two angular position sensors and measuring the phase angle between them. This procedure can be used within the Allison T56 turboprop engine.
Finally, (as described within the abstract for US Patent 5257535), if the mechanical system involves a right angle gearbox, then the axial reaction force felt by the inputting shaft/pinion could be associated with the torque felt by the output shaft(s). The axial input stress must first be calibrated against the output torque. The input stress may be nanzqz measured via strain gauge measurement in the input pinion bearing housing. The output torque is readily measured employing a static torque meter.
The torque sensor can function like a mechanical fuse and is a key component to get accurate measurements. However, improper setting up the torque sensor can harm the device permanently, costing money and time. Hence, the torque sensor needs to be properly installed to ensure better performance and longevity.
The performance and longevity from the load cell and its reading accuracy is going to be afflicted with the style of the driveline. The shaft becomes unstable at the critical speed from the driveline to result in torsional vibration, which can damage the torque sensor. It is actually necessary to direct the strain with an exact point for accurate torque measurement. This point is normally the weakest point of the sensor structure. Hence, the torque sensor is purposely made to be one of the weaker elements of the driveline.