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 rotary torque sensor. Static torque is relatively simple to measure. Dynamic torque, on the contrary, is not easy to measure, because it generally requires transfer of some effect (electric, hydraulic or magnetic) from the shaft being measured to a static system.
One way to achieve this is to condition the shaft or a member connected to the shaft with several permanent magnetic domains. The magnetic characteristics of these domains will vary based on the applied torque, and therefore can be measured using non-contact sensors. Such magnetoelastic torque sensors are generally employed 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 way to power the strain gauge bridge is essential, and also a way to receive the signal from your rotating shaft. This is often accomplished using slip rings, wireless telemetry, or rotary transformers. Newer kinds of torque transducers add conditioning electronics and an A/D converter to the rotating shaft. Stator electronics then read the digital signals and convert those signals to a high-level analog output signal, like /-10VDC.
A far more recent development is the use of SAW devices connected to the shaft and remotely interrogated. The stress on these tiny devices because the shaft flexes could be read remotely and output without making use of 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.
Another way to multi axis load cell is by way of 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 technique is utilized in the Allison T56 turboprop engine.
Finally, (as described in the abstract for US Patent 5257535), in the event the mechanical system involves the right angle gearbox, then the axial reaction force experienced by the inputting shaft/pinion may be linked to the torque felt by the output shaft(s). The axial input stress must first be calibrated from the output torque. The input stress may be nanzqz measured via strain gauge measurement from the input pinion bearing housing. The output torque is easily measured using a static torque meter.
The torque sensor can function such as a mechanical fuse and it is an important component to obtain accurate measurements. However, improper installing of the torque sensor can damage the device permanently, costing time and money. Hence, the torque sensor has to be properly installed to make sure better performance and longevity.
The performance and longevity in the compression load cell along with its reading accuracy is going to be afflicted with the appearance of the driveline. The shaft becomes unstable on the critical speed of the driveline to result in torsional vibration, which can harm the torque sensor. It really is required to direct the strain with an exact point for accurate torque measurement. This time is typically the weakest reason for the sensor structure. Hence, the torque sensor is purposely designed to be one of many weaker elements of the driveline.