The belt pulleys are the second major component of the belt drive. Their function is to drive the belt, so that it can transmit the motion and torque from the driver shaft to the driven shaft by friction in v-belts and micro v-belts or by the toothed profile in synchronous/timing belts.
All of the main dimensions of the belt pulleys are under standardization, which makes for simple and easy transmission design, exploitation and repair. The belt pulleys are made of cast iron, steel or aluminum and are supplied with a pilot or center opening or with a tapered bushing aperture.