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Unformatted text preview: is compound with gear B . 458 l Theory of Machines This compound gear B -D is mounted on the arm or spindle F which is rigidly connected with a hollow
sleeve G. The sleeve revolves freely loose on the axes of the driving and driven shafts. Fig. 13.20. Humpage’s speed reduction gear. 2. Differential gear of an automobile. The differential gear used in the rear drive of an
automobile is shown in Fig. 13.21. Its function is
(a) to transmit motion from the engine shaft to the rear driving wheels, and
(b) to rotate the rear wheels at different speeds while the automobile is taking a turn.
As long as the automobile is running on a straight path, the rear wheels are driven directly by
the engine and speed of both the wheels is same. But when the automobile is taking a turn, the outer
wheel will run faster than the * inner wheel because at that time the outer rear wheel has to cover more
distance than the inner rear wheel. This is achieved by epicyclic gear train with bevel gears as shown
in Fig. 13.21.
The bevel gear A (known as pinion) is keyed to
the propeller shaft driven from the engine shaft through
universal coupling. This gear A drives the gear B (known
as crown gear) which rotates freely on the axle P. Two
equal gears C and D are mounted on two separate parts P
and Q of the rear axles respectively. These gears, in turn,
mesh with equal pinions E and F which can rotate freely
on the spindle provided on the arm attached to gear B .
When the automobile runs on a straight path, the
gears C and D must rotate together. These gears are rotated
through the spindle on the gear B . The gears E and F do
not rotate on the spindle. But when the automobile is taking
Fig. 13.21. Differential gear of an automobile.
a turn, the inner rear wheel should have lesser speed than
the outer rear wheel and due to relative speed of the inner and outer gears D and C, the gears E and F
start rotating about the spindle axis and at the same time revolve about the axle axis.
Due to this epicyclic effect, the speed of the inner rear wheel decreases by a certain amount
and the speed of the outer rear wh...
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This note was uploaded on 02/13/2014 for the course MIE 301 taught by Professor Celghorn during the Fall '08 term at University of Toronto- Toronto.
- Fall '08