What is torque?

Torque is the rotational equivalent of force.Specifically,it is the force exerted at a certain distance from the axis of rotation of the object.Just as a force applied to an object causes it to move linearly,a torque applied to an object causes it to rotate about the pivot point.The pivot point is called the axis of rotation,and the vertical distance between the force and the axis of rotation is called the moment arm.That's why torque is also called moment of force.In the simplest case,the force applied is perpendicular to the axis of rotation.In this case,the torque is simply the product of the force and its distance from the axis of rotation:

But in many applications,forces do not occur perpendicular to the axis of rotation.In this case,the angle of the force must be considered to find the length of the moment arm:

Torque is commonly denoted with a capital “T,” but the correct symbol is the Greek letter tau,“τ.”When torque is referred to as a moment of force,the symbol “M” is used.

Torque is a vector,which means it has both magnitude and direction.The direction of torque can be found by using the right-hand rule.Curl the fingers of your right hand from d(or r,for radius)to F.When this is done,point your thumb in the direction of torque.

In determining the size of linear motion applications,it is important to understand the torque requirements and limitations of all components in the system.The required torque is one of the key parameters to determine the motor size.In most applications,both peak torque(which usually occurs when accelerating or holding a load)and continuous or RMS torque must be considered.In addition,the shafts and other components that transmit torque along the drive train(such as gearbox shafts,couplings,and screw shafts)must also be able to withstand the peak torque applied.

The terms "torque" and "moment" are often used interchangeably.Although the two are similar,torque produces rotation about an axis,and torque is the force applied at a distance where rotation does not occur.For example,a screw has a rotating axis,so a force applied at a certain distance from that axis will cause the screw to rotate.a profiled rail guide,on the other hand,is fixed and do not rotate.A force applied perpendicular to the guide will produce a moment,but will not cause rotation.