Contactless Torque Sensor

From sports equipment providing performance feedback through the automotive sector to controlling industrial manufacturing, torque sensors are indispensable components of peoples’ everyday lives. The fundamentals of torque sensors involve monitoring the mechanical stress/strain of the material for accurate engine performance, damage prevention, or optimizing power delivery.

Use Cases and Market Overview

One of the most widespread use cases of torque sensors in almost every industry is motor torque monitoring. It can serve to monitor torque limits for damage prevention, upholding its integrity, and optimising performance. Another type of torque sensor that can prevent road incidents is an anti-lock(ABS) braking system found in almost every car worldwide. Not only torque monitoring, but also the application of torque during smart assembly of the bolts, screws, and other components can differentiate between the defective and high-quality products.

There are various commercial sensors able to monitor torque on different equipment, such as rotatory transformers, strain gauges , magnetoelastic, or optical sensors. However, RVmagnetics offers a unique solution, the magnetic glass-coated MicroWire. The sensor of micro-dimension monitoring torsion of the materials in contactless, precisely, in real-time, and thanks to the proportions of the MicroWire, also from the inside of the material, without affecting its integrity. MicroWire can withstand the material’s de­formation, which leads to MicroWire’s e­longation up to 2%.

RVmagnetics' MicroWire can contribute to Industry 4.0. Employ MicroWire in your product to make it smart, save money and the environment, and prolong its life.

Demonstration of Torque Measurement with MicroWire Sensor

In the following video, we demonstrate the use of RVmagnetics’ MicroWire sensor for contactless torque detection.

The main parts of the demonstrator are:

  • electronics which include the driving and processing signal unit (not presented in the video) and the sensing head (the size and shape of a final sensing system are tailor-made to meet the spatial limitations),
  • fixed plastic pipe, onto which a stress-dependant MicroWire is attached with an adhesive,
  • oscilloscope displaying a real-time representation of the MicroWire’s signal and its response to the torque applied on the plastic pipe (such a signal can be digitally processed and transformed to simple voltage or numerical output).

In the video, the torque is generated mechanically by applying the force on the pipe with bare hands. Torsion deformation is transferred to the sensor . The MicroWire attached to the plastic pipe does not have to be in contact with the sensing head, as can be seen in the video. Also, different types and geometries of the coil can be made and used depending on the spatial limitations or clients’ specifications. Information about the applied torque is transferred via the magnetic response of the MicroWire. It is detected by the sensing head and processed by electronics, and the signal is displayed on the oscilloscope’s scre­en in real-time. Displacement of the MicroWire’s peak corresponds to the intensity of applied torque and the direction of the peak’s shift provides information about the direction of applied torque.

Conclusion:

The contactless passive sensor capable of sensing the direction and amount of applied torque is scalable according to the client’s needs and it can be adjusted based on specific requirements. The system also allows addressing more complex tasks, such as creating torque distribution maps along the shaft or other unique needs of the customer. With vast and unique possibilities, it is important to showcase the basics of the system, which we present in the video.