D9T Track-Type Tractor Hydraulic System – Final Drive

Illustration 1 g03470879

Final Drive

(1) Outer Axle Shaft

(2) Sprocket Segments

(3) Inner Planetary Gears

(4) Outer Planetary Gears

(5) Inner Sun Gear

(6) Outer Sun Gear

(7) Outer Carrier

(8) Ring Gear

(9) Inner Carrier

(10) Hub

(11) Duo-Cone Seals

The outer axles transfer power to the final drives. The final drives transfer the power to the tracks. The final drives increase torque by a double speed reduction through the planetary gears.

Outer axle shaft (1) sends power to the final drive. Inner sun gear (5) is splined to outer axle shaft (1) . The rotation of the axle shaft and of the inner sun gear turns inner planetary gears (3) .

Ring gear (8) is a stationary component. As inner planetary gears (3) turn, the gears move around the inside of ring gear (8) . The movement of inner planetary gears (3) around the inside of ring gear (8) causes inner carrier (9) to turn.

Inner carrier (9) is splined to outer sun gear (6) . The rotation of inner carrier (9) causes outer planetary gears (4) to turn.

The outer planetary gears move around the inside of ring gear (8) . This movement causes outer carrier (7) and hub (10) to turn. This sends the power to sprocket segments (2) and to the track.

Rotating components pass through the oil that is held in the final drive. This is known as “splash lubrication”.

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