793D Off-Highway Truck Power Train; Differential and Bevel Gear & Final Drive

1.-Differential and Bevel Gear

Illustration 1	g01198209
Differential and bevel gear (1) Shims (2) Spider (3) Differential housing (4) Differential bevel pinions (four) (5) Shims (6) Retainer (7) Bearing (8) Thrust pin (9) Bevel gear (10) Side gears (two) (11) Differential housing (12) Thrust washers (13) Bearings (14) Adjusting nut (15) Carrier assembly (16) Bevel pinion (17) Shims (18) Bearing cage(19) Bearings

The power that is sent to the wheels is divided by the differential. The amount of power that is sent to each wheel is balanced by the differential. During a turn, the differential allows the inner wheel to rotate at a slower rate than the outer wheel. The differential still sends the same amount of torque to each wheel.

The differential and bevel gear is fastened to the rear axle housing. The differential and bevel gear connect the output shaft of the transmission to the drive axles. The output shaft of the transmission is connected to bevel pinion (16) by splines. Bevel pinion (16) turns bevel gear (9). Bevel gear (9) is fastened to differential housing (3). There are four differential bevel pinions (4). Differential bevel pinions (4) turn freely on spider (2). Each differential bevel pinion (4) has a double bearing assembly in order to carry the drive load of the differential bevel pinion. Differential housing (3) and differential housing (11) are bolted together in order to hold spider (2). Differential housing (3) and differential housing (11) rotate together with bevel gear (9). The housings are driven by bevel gear (9). The housings are supported by bearings.

Differential bevel pinions (4) are engaged at a 90 degree angle with two straight side gears (10). The side gears are connected to the drive axles by splines.

When the machine is moving in a straight direction and each drive wheel has the same amount of traction, both wheels receive the same amount of load. The same amount of torque is felt on each axle. This torque holds differential bevel pinions (4) so that the differential bevel pinions do not turn on spider (2). This will provide the same effect as if both drive wheels are fastened to the same drive axle.

When different loads are put on the drive wheels, differential bevel pinions (4) will turn because the forces are different on the opposite sides of the differential. During a turn, the rotation of the differential bevel pinions will allow a slower rotation of the inside wheel and a faster rotation of the outside wheel. The machine is driven with full power in a turn.

Side gears (10) turn against thrust washers (12). The end thrust of the differential bevel pinions (4) against the differential case is taken by a double bearing assembly. The bearing assemblies must be changed in sets of two.

Thrust pin (7) in the rear housing provides support for carrier assembly (15). Carrier assembly (15) carries a high thrust load.

Shims (17) are located under bearing cage (18). When bearing cage (18) is installed, the shims determine the end play of bearings (19) for bevel pinion (16) .

Shims (1) affect the tooth contact between bevel gear (9) and bevel pinion (16). Changing the shims would also affect the pinion bearing preload. Shims (5) and retainer (6) affect the backlash of the gears.

Adjusting nut (17) and adjusting nut (5) are used to make an adjustment between bevel pinion (14) and bevel gear (8). The nuts are also used to make an adjustment to the bearing preload of bearing (16) and bearing (6) .

The differential receives lubrication from the oil in the axle housing. The gear pump for the rear axle provides lubrication oil through the final drive bypass manifold. As the parts rotate, the oil is thrown around the inside of the housing. Spiral grooves in thrust washers (12) allow the lubricant to flow between the thrust washers and side gears (10) .

2.-Final Drive

Illustration 1	g01198466
(1) Brake (2) Bearing (3) Bearing (4) Hub (5) Ring gear (6) Planetary gears (7) Ring gear (8) Planetary carrier (9) Planetary gears (10) Planetary carrier (11) Sun gear (12) Sun gear (13) Wheel(14) Spindle housing

Each of the two final drives has the same components. A final drive causes the last speed reduction in the power train and the last torque increase in the power train.

Spindle housing (14) is fastened to the axle housing. Hub (4) is splined to spindle housing (14) and to ring gear (5). Ring gear (5) is splined to ring gear (7). Ring gear (7), ring gear (5), hub (4), and spindle housing (14) are stationary.

The axle shaft is connected to the differential by spindles in sun gear (12). Sun gear (12) is engaged with planetary gears (6). Planetary gears (6) are held in planetary carrier (8). Planetary carrier (8) is connected to sun gear (11) by splines. Sun gear (11) is engaged with planetary gears (9). Planetary gears (9) are held in planetary carrier (10). Planetary carrier (10) is connected to wheel (13) .

Power from the differential turns the axle shaft. The axle shaft turns sun gear (12). Sun gear (12) turns planetary gear (6). Because ring gear (5) is held stationary by hub (4), the planetary gears move around the inside of ring gear (5). The movement of the planetary gears causes planetary carrier (8) to turn. Carrier (8) is turned in the same direction as sun gear (12), but at a slower speed. Carrier (8) turns sun gear (11). Sun gear (11) turns planetary gear (9). Because ring gear (7) is held stationary by ring gear (5), the planetary gears move around the inside of ring gear (7). The movement of the planetary gears causes planetary carrier (10) to turn. Carrier (10) is turned in the same direction as sun gear (11), but at a slower speed. Carrier (10) drives wheel (13) .

The final drives receive lubrication by the rotation of the gears in the oil. The differential and the final drives use the same lubricant.

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793D Off-Highway Truck Power Train; Differential and Bevel Gear & Final Drive 2013-01-06T20:10:00-08:00 Rating: 4.5 Diposkan Oleh: Unknown