Actuator torque is a quantitative expression of the amount of torque that an actuator is capable of producing. Torque is a term used to define the degree to which a driving force turns an object around its own axis or pivot. A good example of this is a high performance racing car that tends to twist or lift on one side when the engine is humming. This reaction is caused by the torque of the engine, which, although its output power is utilized to drive the car forward along its own axis, exerts a rotational motion about the car’s axis. Simply put, the more torque a device can generate, the more power it will be able to exert over a wider range of operational loads.
The straight line movement experienced when something is pressed is a practical manifestation of power. Torque, on the other hand, can best be described as a result of applying force to a wrench, which shows a bolt around its axis. The same goes for a screwdriver used to loosen a very stiff screw. If the screwdriver handle is well developed and does not slip into the handyman’s hand, a large amount of torque is generated and applied to the screw by the force exerted on the trigger handle. The same principles apply to conditions that affect the ability of similar forces to generate rotational motion also apply to the definition of actuator torque.
Actuator torque is an important part of rating specifications of any actuator. The torque on the device will dictate what applications the actuator will realistically handle. A low torque will mean that the actuator will be able to maintain its output power over a very narrow load range. As soon as this area is exceeded, the actuator will be “suffocated” and will not be able to continue to exercise its working motion effectively. In contrast, a high torque actuator would be uncomfortable to handle a much wider range of load variations.
This concept of actuator torque is perhaps best demonstrated by a car approaching a steep hill in high gear. In this equipment configuration, is not able to develop much torque and, to effectively climb the ground motor, a lower gear will have to be selected. The same principle applies to an actuator with internal mechanism design dictates how well the actuator motor translates its latent power into usable torque. High torque values are not always called for, so not all actuators develop the same torque outputs even though they may have similar power plants. This makes informed choices critical when selecting devices for applications that require high actuator torque values.