In physics and mechanics, the torque is the rotational force, or the force needed to cause an object to rotate about an axis. In most cases, more torque is needed to start rotational motion than is necessary to keep it running after it has started. This first force is called breakaway torque.
The amount of breakaway torque needed to move anything is partly determined by static friction. Static friction is the force that exists between two physical bodies to keep them from moving. For example, a wing nut can have high torque burner because there is a lot of static friction between the nut and the bolt. If, on the other hand, the bolt is lubricated, the torque will be lower because the static friction is reduced.
The torque is almost always discussed in one of two contexts, either the power of a motor, or the force needed to unscrew a threaded fastener, such as a nut. If a mechanic wants to remove a nut from a bolt, he or she must apply torque to the nut with a wrench. As everyone who has done this knows, turning the wrench takes a lot of power at first, but usually becomes easier after a few turns.
Mechanics and engineers often measure breaking torque on threaded fasteners to, among other things, ensure product integrity as part of a process called torque overhaul. If the detachment force of a nut is too low, the vibration of equipment may cause the nut to loosen; If it is too high, the threads strip and the bolt may be impossible to remove. Part of testing the fastener includes measuring the torque that is currently moving after the torque has been overcome. Revision can either be done using sensors to measure torque, or by a trained operator to add torque by hand.
Another area where torque bursting is important is in cylindrical engines. As with threaded fasteners, torque exits are on a motor greater than the running torque. In an engine, the torque is used to spin a crankshaft. The crankshaft in turn causes the pistons to move up and down.
An engine designed with just enough power to keep the engine running will fail. The motor must also have enough power to get the movement started in the first place. But it’s a delicate balance. If the engine is allowed to continue to run at enough torque to cause a breakaway, it may overheat. When the circuit breaker is achieved, the engine torque should be reduced to a normal operating speed.
- The torque can refer to the force needed to strike one faster than a nut.
- Torque is required to turn off the crankshaft in an engine.