COVER 3S8077 - Caterpillar

Illustration 1 g01074845
Cross-sectional View of Final Drive Planetary (1) Brake Pack (2) Coupler (Gear Selector) (3) Piston (Gear Selector) (4) Top Shift Port (5) Input Shaft (Sun Gear) (6) Large Spring (Shifter) (7) Small Spring (Shifter) (8) First Stage Carrier (9) Second Stage Carrier (10) Third Stage Carrier (11) Shifter Assembly (Gear Selector) (12) Planetary AssemblyNote: The top half of the planetary is shown in the High Speed mode. The bottom half of the planetary picture is shown in the low speed mode.The propel motor is mounted to planetary assembly (12). The travel/pave/maneuver speed control that is located on the operator console determines the speed of the machine. The switch is connected to the propel electronic control module, which operates the two solenoid valves on the control manifold. The solenoid valves route auxiliary system oil to the planetary assembly on each side of the machine.The planetary group controls the high speed and low speed. The left planetary assembly and the right planetary assembly operate in the same exact manner. Power is transferred from the propel motors to the planetary assembly by the motor output shaft. Power is transferred from the planetary assembly to the tracks. The planetary groups give a double reduction through the use of planetary gears and a sliding coupler.In high speed operation, oil flows through the top shift port (4) to the piston (gear selector) (3). The small spring (shifter) (7) pushes the coupler (gear selector) (2) in order to engage input sun gear (5). The input sun gear (5) spins the second stage sun gear. The spinning of the second stage sun gear rotates the second stage carrier (9) that is connected to the third stage sun gear. The third stage of the planetary sun gear spins the third stage carrier (10) which turns the ring gear. When the machine is in high gear, the planetary assembly has a 39.1:1 gear ratio.In low speed operation, the large spring (shifter) (6) pushes the piston (gear selector) (3) to the right. This function disengages the coupler (gear selector) (2) from input sun gear (5). The input sun gear (5) engages first stage carrier (8). Power flows into the input sun gear (5) through the first stage planetary gears. The first stage planetary gears turn the first stage carrier (8) which is connected to the coupler (gear selector) (2). The coupler (gear selector) (2) connects to the second stage sun gear which spins the second stage carrier (9). The second stage planetary gear rotates the second stage carrier (9) which connects to the third stage sun gear. The third stage sun gear spins the third stage carrier (10) which turns the ring gear. When the machine is in low gear, the planetary assembly has a gear ratio of 151.6:1.The planetary assemblies have an exclusive oil supply. All components get lubrication as the gears move and oil is thrown about the planetary housing. This method is called splash lubrication. The bearings in the planetary group are the roller bearing