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 Miniature 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 achieve this is to condition the shaft or a member connected to the shaft with a number of permanent magnetic domains. The magnetic characteristics of those domains can vary based on the applied torque, and therefore may be measured using non-contact sensors. Such magnetoelastic torque sensors are typically used for in-vehicle applications on racecars, automobiles, aircraft, and hovercraft.
Commonly, torque sensors or torque transducers use strain gauges placed on a rotating shaft or axle. Using this method, a way to power the strain gauge bridge is essential, as well as a means to have the signal from your rotating shaft. This is often accomplished using slip rings, wireless telemetry, or rotary transformers. Newer varieties of torque transducers add conditioning electronics plus an A/D converter to the rotating shaft. Stator electronics then browse the digital signals and convert those signals to a high-level analog output signal, including /-10VDC.
A much more recent development is using SAW devices connected to the shaft and remotely interrogated. The stress 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 utilization 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 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 using two angular position sensors and measuring the phase angle between the two. This technique is utilized inside 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 your axial reaction force experienced by the inputting shaft/pinion could be associated with the torque gone through by the output shaft(s). The axial input stress must first be calibrated up against the output torque. The input stress can be easily measured wbtbtc strain gauge measurement of 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 is also a vital 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 has to be properly installed to ensure better performance and longevity.
The performance and longevity from the 3 Axis Load Cell along with its reading accuracy will likely be affected by the design from the driveline. The shaft becomes unstable on the critical speed from the driveline and causes torsional vibration, which can damage the torque sensor. It is required to direct the strain to an exact point for accurate torque measurement. This time is typically the weakest reason for the sensor structure. Hence, the torque sensor is purposely created to be one of the weaker components of the driveline.