A torque sensor, torque transducer or torque meter is a device for computing and recording the torque on a rotating system, like an engine, crankshaft, gearbox, transmission, rotor, a bicycle crank or torque sensor. Static torque is comparatively very easy to measure. Dynamic torque, on the other hand, is not easy 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 achieve this is always to condition the shaft or perhaps a member connected to the shaft with a number of permanent magnetic domains. The magnetic characteristics of those domains can vary according to the applied torque, and so may 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 necessary, and also a way to get the signal through the rotating shaft. This can be accomplished using slip rings, wireless telemetry, or rotary transformers. Newer types of torque transducers add conditioning electronics and an A/D converter for the rotating shaft. Stator electronics then read the digital signals and convert those signals to a high-level analog output signal, such as /-10VDC.
A more recent development is the use of SAW devices attached to the shaft and remotely interrogated. The strain on these tiny devices because the shaft flexes may be read remotely and output without making use of attached electronics on the shaft. The probable first use in volume will be in the automotive field as, of May 2009, Schott announced it has a SAW sensor package viable for in vehicle uses.
A different way to 3 axis load cell is by way of twist angle measurement or phase shift measurement, whereby the angle of twist caused by applied torque is measured by utilizing two angular position sensors and measuring the phase angle between them. This method can be used within the Allison T56 turboprop engine.
Finally, (as described inside the abstract for US Patent 5257535), when the mechanical system involves the right angle gearbox, then this axial reaction force experienced by the inputting shaft/pinion may 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 nanzqz measured via strain gauge measurement from the input pinion bearing housing. The output torque is readily measured utilizing a static torque meter.
The torque sensor can function such as a mechanical fuse and it is an important component to get accurate measurements. However, improper installing of the torque sensor can harm the device permanently, costing money and time. Hence, the torque sensor needs to be properly installed to make sure better performance and longevity.
The performance and longevity in the miniature load cell as well as its reading accuracy is going to be affected by the design of the driveline. The shaft becomes unstable on the critical speed of the driveline and results in torsional vibration, which can damage the torque sensor. It is required to direct the strain with an exact point for accurate torque measurement. This aspect is normally the weakest reason for the sensor structure. Hence, the torque sensor is purposely created to be one of the weaker elements of the driveline.