A torque sensor, torque transducer or torque meter is a device for measuring and recording the torque on a rotating system, such as an engine, crankshaft, gearbox, transmission, rotor, a bicycle crank or Compression Load Cell. Static torque is fairly simple to measure. Dynamic torque, however, is 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 do this is to condition the shaft or perhaps a member connected to the shaft with a series of permanent magnetic domains. The magnetic characteristics of those domains will be different based on the applied torque, and so could be measured using non-contact sensors. Such magnetoelastic torque sensors are generally utilized for in-vehicle applications on racecars, automobiles, aircraft, and hovercraft.
Commonly, torque sensors or torque transducers use strain gauges applied to a rotating shaft or axle. With this particular method, a means to power the strain gauge bridge is essential, and also a means to receive the signal through the rotating shaft. This is often accomplished using slip rings, wireless telemetry, or rotary transformers. Newer types of torque transducers add conditioning electronics as well as an A/D converter to the rotating shaft. Stator electronics then read the digital signals and convert those signals to some high-level analog output signal, such as /-10VDC.
A much more recent development is the use of SAW devices attached to the shaft and remotely interrogated. The stress on these tiny devices since the shaft flexes can be read remotely and output without making use of attached electronics on the shaft. The probable first use within volume will be in the automotive field as, of May 2009, Schott announced it has a SAW sensor package viable for in vehicle uses.
Another way to measure Torque Transducer is by way of twist angle measurement or phase shift measurement, whereby the angle of twist as a result of applied torque is measured by using two angular position sensors and measuring the phase angle between them. This procedure is used within the Allison T56 turboprop engine.
Finally, (as described within the abstract for US Patent 5257535), in the event the mechanical system involves the right angle gearbox, then your axial reaction force gone through by the inputting shaft/pinion could 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 simply measured wbtbtc 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 such as a mechanical fuse and it is a key component to have accurate measurements. However, improper installation of the torque sensor can harm the device permanently, costing money and time. Hence, the torque sensor must be properly installed to ensure better performance and longevity.
The performance and longevity of the 3 Axis Load Cell and its reading accuracy is going to be afflicted with the design from the driveline. The shaft becomes unstable on the critical speed from the driveline and results in torsional vibration, which can damage the torque sensor. It is actually essential 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.