Reduction drive

A reduction drive is a mechanical device that changes rotational speed. It is used in engines of all kinds to raise the torque per revolution of a shaft, and the gearbox of a car is a common example. Household uses include washing machines, food blenders and window winders. A reduction drive can be a gear train or belt driven, and a small planetary version uses ball bearings in an epicyclic arrangement in place of toothed gears. Planetary reduction drives sit between the shaft of a variable capacitor and the tuning knob of a radio so that fine adjustments are smooth and free of backlash.