Cycloidal gearboxes
Cycloidal gearboxes or reducers contain four simple components: a high-speed input shaft, a single or compound cycloidal cam, cam followers or rollers, and a slow-speed output shaft. The insight shaft attaches to an eccentric drive member that induces eccentric rotation of the cycloidal cam. In substance reducers, the first track of the cycloidal cam lobes engages cam fans in the casing. Cylindrical cam followers become teeth on the inner gear, and the Cycloidal gearbox number of cam followers exceeds the number of cam lobes. The second track of compound cam lobes engages with cam followers on the output shaft and transforms the cam’s eccentric rotation into concentric rotation of the output shaft, thus raising torque and reducing speed.
Compound cycloidal gearboxes offer ratios ranging from only 10:1 to 300:1 without stacking stages, as in standard planetary gearboxes. The gearbox’s compound decrease and may be calculated using:
where nhsg = the number of followers or rollers in the fixed housing and nops = the number for followers or rollers in the slow rate output shaft (flange).
There are many commercial variations of cycloidal reducers. And unlike planetary gearboxes where variations derive from gear geometry, heat treatment, and finishing processes, cycloidal variations share simple design principles but generate cycloidal motion in different ways.
Planetary gearboxes
Planetary gearboxes are made of three fundamental force-transmitting elements: a sun gear, three or more satellite or planet gears, and an internal ring gear. In a typical gearbox, the sun gear attaches to the insight shaft, which is linked to the servomotor. Sunlight gear transmits engine rotation to the satellites which, subsequently, rotate in the stationary ring gear. The ring gear is part of the gearbox housing. Satellite gears rotate on rigid shafts linked to the earth carrier and trigger the planet carrier to rotate and, 
thus, turn the output shaft. The gearbox gives the output shaft higher torque and lower rpm.
