Gear and Gear Trains

Some important features of gears and gear trains are:

1. The ratio of the pitch circles of mating gears defines the speed ratio and the mechanical advantage of the gear set.
2. A planetary gear train provides high gear reduction in a compact package.
3. It is possible to design gear teeth for gears that are non-circular, yet still transmit torque smoothly.
4. The speed ratios of chain and belt drives are computed in the same way as gear ratios.