one of the major features that define mechanisms, including rotational drives. The transmission ratio is defined as the ratio of the angular velocities or frequencies of rotation of the components. This usually refers to the ratio of the angular velocity of the driving component to the angular velocity of the driven component: u = ω1/ω2.
The concept of the transmission ratio is applicable both to simple mechanisms (pairs of gears, worm drives, belt drives) and complex multicomponent mechanisms (multiple reduction gears, planetary gears, gearboxes). The transmission ratio of gear drives connected in series is equal to the product of the transmission ratios of these drives.
In addition to the concept of the transmission ratio, the closely related concept of the gear ratio is widely used, especially with respect to gear trains.