Torque sensors, also known as torque sensors, torque sensors, torque meters, are divided into two categories: dynamic and static. Among them, dynamic torque sensors can also be called torque sensors, torque speed sensors, non-contact torque sensors, rotational torque sensors, etc. A torque sensor is a device that detects the perception of torsional torque on various rotating or non rotating mechanical components. The torque sensor converts the physical changes in torque into precise electrical signals. Torque sensors can be applied in the manufacturing of viscometers and electric (pneumatic, hydraulic) torque wrenches. They have the advantages of high accuracy, fast frequency response, good reliability, and long service life.

The torque commonly referred to is the external torque. For example, the rotation of a machine tool spindle is the result of the external torque provided by the power source, while torque is the internal torque. When the spindle is working, the cutting force of the tool reacts with the spindle to produce torsional elastic deformation, which can be used to measure the magnitude of torque. Torque is the moment that causes an object to undergo rotational or torsional deformation, equal to the product of force and force arm.

Torque is the most frequently involved parameter in rotary power systems, and in order to detect rotational torque, torque angle phase difference sensors are commonly used. The sensor is equipped with two sets of gears with identical tooth numbers, shapes, and installation angles at both ends of the elastic shaft, and a proximity (magnetic or optical) sensor is installed on the outside of each gear. When the elastic shaft rotates, these two sets of sensors can measure two sets of pulse waves, and comparing the phase difference between the front and rear edges of these two sets of pulse waves can calculate the amount of torque borne by the elastic shaft. The advantages of this method are: it achieves non-contact transmission of torque signals, and the detection signal is a digital signal; Disadvantages: Large size, difficult to install, and at low speeds, the slow front and rear edges of the pulse wave make it difficult to compare, resulting in poor low-speed performance.

The mature detection method for torque testing is strain electrical measurement technology, which has the advantages of high accuracy, fast frequency response, good reliability, and long service life. Attach a dedicated torsion strain gauge to the tested elastic shaft with strain adhesive and form a strain bridge. If a working power supply is provided to the strain bridge, the electrical signal of the elastic shaft under torsion can be tested. This is the basic torque sensor mode. However, in the rotating power transmission system, the most challenging problem is how to reliably transmit the bridge pressure input and detected strain signal output of the strain bridge on the rotating body between the rotating and stationary parts. The usual approach is to use conductive slip rings.

Due to the frictional contact of the conductive slip ring, the torque sensor inevitably experiences wear and heat generation, which limits the rotational speed of the rotating shaft and the service life of the conductive slip ring. And due to unreliable contact, signal fluctuations can occur, resulting in large measurement errors or even unsuccessful measurements. In order to overcome the defects of conductive slip rings, another method is to use wireless telemetry: amplifying the torque strain signal on the rotating shaft and converting it into a frequency signal through V/F conversion, transmitting it from the rotating shaft to the outside through carrier modulation using wireless transmission, and then using wireless reception to obtain the signal of the rotating shaft being twisted. The energy supply on the rotating shaft is a battery fixed on the rotating shaft. This method is called telemetry torque meter.