MAST AR 0347413 - Caterpillar

Illustration 1 g03416180
Final Drive
(1) Final drive hub
(2) Ring gear
(3) Planetary gears
(4) Planetary carrier
(5) Axle housing
(6) Axle shaft
(7) Sun gear
(8) Wheel assemblyEach final drive has a planetary gear system. Ring gear (2) is fastened to final drive hub (1). Splines connect final drive hub (1) to axle housing (5). Ring gear (2) is held in a stationary position. Planetary gears (3) are held by planetary carrier (4). Planetary carrier (4) is fastened to wheel assembly (8). Splines connect sun gear (7) to axle shaft (6). Splines connect axle shaft (6) to the side gear of the differential.When the side gear of the differential turns, the side gear turns the axle shaft. The axle shaft turns the sun gear. The sun gear turns the planetary gears. Since the ring gear is held stationary, the planetary gears move around the inside of the ring gear. The planetary gears turn in the same direction of the sun gear but at a slower speed. The movement of the planetary gears causes the planetary carrier to turn. The planetary gear turns the wheel assembly and wheels.