A torque sensor, torque transducer or torque meter is actually a device for computing and recording the torque on a rotating system, such as an engine, crankshaft, gearbox, transmission, rotor, a bicycle crank or torque sensor. Static torque is comparatively simple to measure. Dynamic torque, on the other hand, is difficult to measure, because it generally requires transfer of some effect (electric, hydraulic or magnetic) through the shaft being measured to a static system.
One method to make this happen is always to condition the shaft or a member attached to the shaft with a series of permanent magnetic domains. The magnetic characteristics of such domains will vary according to the applied torque, and thus may be measured using non-contact sensors. Such magnetoelastic torque sensors are typically 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. Using this method, a method to power the strain gauge bridge is important, and also a means to receive the signal from your rotating shaft. This can be accomplished using slip rings, wireless telemetry, or rotary transformers. Newer varieties of torque transducers add conditioning electronics as well as an A/D converter towards the rotating shaft. Stator electronics then read the digital signals and convert those signals to your 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 since the shaft flexes can 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 has a SAW sensor package viable for in vehicle uses.
Another way to 3 axis load cell 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 making use of two angular position sensors and measuring the phase angle between them. This procedure is used within the Allison T56 turboprop engine.
Finally, (as described inside the abstract for US Patent 5257535), if the mechanical system involves the right angle gearbox, then the axial reaction force gone through by the inputting shaft/pinion may be related to the torque experienced by the output shaft(s). The axial input stress must first be calibrated up against the output torque. The input stress could be nanzqz measured via strain gauge measurement in the input pinion bearing housing. The output torque is easily measured using a static torque meter.
The torque sensor can function like a mechanical fuse and is also a vital component to have accurate measurements. However, improper installing of the torque sensor can harm the device permanently, costing time and money. Hence, the torque sensor must be properly installed to ensure better performance and longevity.
The performance and longevity of the load cell and its reading accuracy is going to be afflicted with the design of the driveline. The shaft becomes unstable in the critical speed of the driveline and results in torsional vibration, which can damage the torque sensor. It really is required to direct the strain with an exact point for accurate torque measurement. This aspect is usually the weakest reason for the sensor structure. Hence, the torque sensor is purposely created to be one of many weaker components of the driveline.