What are Torque motors?
A torque motor is a toroid shaped motor which can directly drive the application without additional mechanics, like worm wheels, belts, or pulleys. Because of their shape, torque motors are able to generate a lot of torque, but relatively little RPM compared to conventional servomotors. The latter can reach a much higher RPM, but generate less torque. To reach the desired speed to torque ratio, a torque motor is therefore often fitted with a gearbox. This gearing reduces the efficiency and accuracy, however.
There are two types of direct drive torque motors: the outrunner and the inrunner torque motors. In case of the outrunner motor, the rotor (the permanent magnet ring) is located on the outside of the stator (the electromagnet and lamination). In case of a inrunner motor, the rotor is located on the inside of the stator. Both type of torque motors, each with their own advantages, still function in a similar way.
In the video below, you can see a visual representation of how a torque motor works. In the clip, you can see how a magnetic field circulates due to the electromagnetic charge. Orange represents the negative electromagnetic charge in this case and blue the positive electromagnetic charge. The ratio between the voltage and current demand can be adjusted by adjusting the number of windings and/or winding configuration. This makes the motor usable for various application areas, such as semicon, robotics, food, and packaging