Type "A" and "B" Final Drives
 | |
| Illustration 1 | g00865166 |
Final Drive (1) Planetary carrier (first stage) (2) Bolt (3) Sun gear (second stage) (4) Planetary carrier (second stage) (5) Gear coupling (6) Dowel pin (7) Bearing (8) Motor housing (9) Travel motor (10) Cover (11) Sun gear (first stage) (12) Roller bearing (13) Planetary shaft (first stage) (14) Planetary gear (first stage) (15) Ring gear (first gear) (16) Roller bearing (17) Planetary gear (second stage) (18) Planetary shaft (second stage) (19) Bolt (20) Travel motor output shaft (21) Housing (sprocket) (24) Ring gear (second stage) | |
The final drive reduces the rotating speed of travel motor (9). Travel motor output shaft (20) is splined to first stage sun gear (11) of the final drive.
The final drive consists of two groups. The first group is the two stages of the planetary gears. The second group is the output group.
The two stages of the planetary gears contain the following components.
- The first stage is made up of sun gear (11), planetary gears (14), planetary carrier (1) and ring gear (15) .
- The second stage is made up of sun gear (3), planetary gears (17), planetary carrier (4) and ring gear (24) .
The output group is described in the following manner. The rotation of housing (21) develops output torque that is used to drive the track. Housing (21), ring gears (15) and (24), and cover (10) are held together with bolts (1). Housing (21), ring gears (15) and (24), and cover (10) are held in position by bearing (7). Housing (21) and cover (10) rotate with ring gear (24) .
The planetary gears reduce the travel speed. The travel speed is reduced by the ratio of teeth of the sun gear and the ring gear. The compact travel drive offers a greater reduction ratio when the sun gear is incorporated in the ring gear.
Planetary Gear Operation
The rotation of travel motor output shaft (20) is transferred to sun gear (11). Sun gear (11) is splined to output shaft (20). Sun gear (11) rotates clockwise. The travel drive assembly operates in the following manner.
 | |
| Illustration 2 | g00862323 |
First Stage Reduction Group (1) Planetary carrier (first stage) (11) Sun gear (first stage) (12) Roller bearing (first stage) (13) Planetary shaft (first stage) (14) Planetary gear (first stage) (15 ) Ring gear (first stage) (22) Rotation of the first stage reduction group | |
Sun gear (11) engages with planetary gear (14) in the first stage reduction group. Planetary gear (14) rotates counterclockwise as sun gear (11) rotates clockwise. As ring gear (15) rotates, ring gear (15) circles around sun gear (10) clockwise. Planetary gear (14) is mounted to planetary carrier (1) by planetary shaft (13) and roller bearing (12). The assembly of planetary carrier (1) rotates clockwise.
 | |
| Illustration 3 | g00862330 |
Splines in Engagement (1) Planetary carrier (first stage) (3) Sun gear (second stage) (23) Splines in engagement | |
The rotation of planetary carrier (1) is transferred to sun gear (3) of the second stage. Planetary carrier (1) is splined to sun gear (3) by splines (23). Sun gear (3) rotates clockwise.
The splines on planetary carrier (4) of the second stage engage with the teeth on the outer circumference of motor housing (8) through coupling gear (5). The motor housing is bolted to the track frame. Planetary carrier (4) does not rotate. The axis of planetary gear (17) is stationary. This causes ring gear (24) to rotate counterclockwise.
Ring gear (24) and sprocket housing (21) are held together with bolts (2). The sprocket wheel is bolted to sprocket housing (21). The torque of sun gear (3) is transferred to sprocket housing (21). This causes the sprocket to rotate counterclockwise. The right track rotates in the forward direction.