Torque sensors, also known as torque sensors, torque sensors, torque sensors, torque meters, are divided into two categories: dynamic and static, among which dynamic torque sensors can also be called torque sensors, torque speed sensors, non-contact torque sensors, rotary torque sensors, etc. Torque sensors are the detection of torsional torque perception on a variety of rotating or non-rotating mechanical components. Torque sensors convert physical changes in torque into precise electrical signals. Torque transducers can be used in the manufacture of viscometers, electric (pneumatic, hydraulic) torque wrenches, which have the advantages of high precision, fast frequency response, good reliability and long life.

How torque sensors work

Toothed discs are installed on both sides of the torsion shaft between the drive source and the load. They are equipped with two corresponding magnetoelectric sensors next to them. The structure of the magnetoelectric sensor is shown in the figure. The detection element part of the sensor is composed of a permanent magnet, an induction coil and an iron core. The magnetic field lines generated by the permanent magnet are connected to the toothed disc. When the toothed disc rotates, the convex concave tooth of the disc causes a change in the air gap of the magnetic circuit, so the magnetic flux also changes, and the alternating voltage is induced in the coil, and its frequency is numerically equal to the product of the number of teeth on the disc and the number of revolutions. When the torque acts on the torsion shaft, there is a phase difference between the induced voltages U1 and U2 output by the two magnetoelectric sensors. This phase difference is directly proportional to the torsion angle of the torsion axis. In this way, the transducer converts the torque-induced torsional angle into an electrical signal for the phase difference.

How to install and use the torque sensor

1. The torque sensor can be installed horizontally or vertically

2. Power equipment, sensors, and load equipment should be installed on a solid foundation to avoid excessive vibration, otherwise data instability may occur, reduce measurement accuracy, and even damage the sensor.

3. It is connected by elastic pin coupling or rigid coupling.

4. The middle part of the sensor cannot be rigidly fixed, and flexible connection should be adopted

5. The concentricity of the axis of power equipment, sensor and load equipment should be less than Φ0.03mm.

6. When the sensor is used vertically, there should be a support partition at the input end and the output end, so that the sensor will not be affected by the gravity of the power source and load, and the measurement accuracy has been guaranteed.

Classification of torque sensors: non-contact torque sensors, strain gauge torque sensors, phase difference torque and speed sensors

1. Let’s talk about the non-contact torque sensor first: its input shaft and output shaft are connected by a torsion bar, there is a spline on the input shaft, and the keyway is on the output shaft. This process causes the magnetic inductance on the spline to change, which is converted into a voltage signal through the coil.

2. Strain gauge torque sensor: its principle is to use the elastic shaft and paste the strain gauge to form a measuring bridge, when the elastic shaft is slightly deformed by the torque, the resistance value of the bridge will change, and then the electrical signal has changed, so as to realize the measurement of torque.

3. Phase difference torque and speed sensor: Its principle is to study the magnetoelectric phase difference torque measurement technology, and install two sets of gears with the same number of teeth, shape and installation angle at both ends of the elastic shaft, and install a proximity sensor on the outside of the gear.

Application of torque transducers

As a precision measuring instrument for measuring various torque, speed and mechanical power, torque sensor is mainly used in the detection of rotating power equipment such as electric motors and engines. Torque and power testing in locomotives, automobiles, airplanes, mining machinery, etc. Whether it is engineering, manufacturing, transportation or scientific research institutes, etc., there are torque sensors.