Epicyclic gear

• An epicyclic gearbox, also known as a planetary gearbox, is a type of automatic transmission system that uses a sun gear, planet gears, and a ring gear to achieve various speed ratios in forward and reverse directions
• In an automobile, an epicyclic gear train is used as a differential gear. The differential gear is located between the drive wheels of the vehicle and allows the wheels to rotate at different speeds while turning
• This is necessary because when a vehicle turns, the outside wheel has to travel farther than the inside wheel and therefore needs to rotate faster