TM 5-3805-290-23-1
THEORY OF OPERATION - CONTINUED
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DIFFERENTIAL
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1.
General. A differential divides and balances power sent to wheels. During a turn, differential allows inside wheel to
rotate at a slower rate in relation to outside wheel. Differential still sends same amount of torque to each wheel.
2.
Straight Forward or Reverse (Rear Axle).
a.
Operation. When machine moves in a straight direction with the same amount of traction under each drive wheel,
the same amount of torque on each axle holds pinions so they do not turn on spider. Bevel pinion turns bevel gear.
Bevel gear turns case. Case turns shaft. Shaft turns side gears through pinions. Pinions do not turn on shaft. Side
gears turn final drive sun gears. Same amount of torque is sent through final drives to each wheel.
b.
Forward or Reverse Turn.
(1)
When machine is in a turn, inside wheel is more resistant than outside wheel to turn. This resistance causes
different torques on opposite sides of differential. Outside wheel turns more easily than inside wheel. Out-
side wheel starts to turn faster than inside wheel.
(2)
Bevel pinion turns bevel gear. Bevel gear turns case. Case turns shaft. Shaft turns side gears through pin-
ions. Since more force is needed to turn one side gear more than other side gear, pinions turn around shaft.
As pinions turn, they move around side gears. Differential allows inside wheel to turn at a slower rate than
outside wheel.
(3)
Same amount of torque is sent through final drives to both inside and outside wheels. This torque is only
equal to amount of torque necessary to turn outside wheel.
