1) A differential gear is an arrangement of bevelled gears that distributes input torsion equally to two planetary gears and side gears, allowing the output shafts to counter-rotate and facilitating turns. 2) The main components are a crown wheel, two planet pinions, and two sun gears. 3) Differentials allow wheels on each side of the vehicle to rotate at different speeds, such as when turning, but have the disadvantage of reduced traction if one wheel loses grip.

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DIFFERENTIAL GEAR
Submitted by,
•D.Ravi Teja,
•Gaurav Mishra,
•Ramana Murthy.

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•Our Objective is to study the differential gear mechanism
What does it mean?
 A differential gear is an arrangement
of bevelled gears in such a manner such
that the input torsion is taken up by a
ring gear and distributed equally through
two planetary gears to the side gears
which drive the shafts on either side.

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VARIOUS COMPONENTS OF
DIFFERENTIAL GEAR:
•1 Crown wheel (GREY)
•2 Planet pinions(BLUE)
•2 Sun gears (RED)
Function:
• Facilitate the faster rotation of outer wheels while taking a turn.
• Transmit power at 90 degrees.

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WORKING PRINCIPLE:
• Allowing the two output shafts to counter-rotate relative to each other.
While moving on a straight path While taking a curved path

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EXPERIMENTAL SETUP:
 Make a chalk mark over graduations of
gears of final drive G, bevel gear A of
differential, the other gear of differential
i.e., C and also over the frame.
 Hold the gears A and C one after the other
and rotate the pinion by handle in order
to count the rotation of gear A or C
(which is held freely) for one complete
rotation of gear G.
 After that hold the gear A by hand and
rotate the disc by hand. After noting the
position of chalk mark of gear C as well
as of gear G. Rotate the disc until gear C
rotates by half revolutions. stop the
rotation. By this time gear G has also
rotated by some fraction of part of one
revolution.

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 Similarly repeat the above by
holding the gear C and rotate the disc
until the gear G rotates further by left
over fraction of part of one
revolution.
 Record the revolution of gear G and
the corresponding revolutions of gear
A and C.
 Repeat the above 2 steps for one,one
and a half revolution of gear C.Note
the corresponding revolution of gear
A for one complete revolution of
gear G.

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OBSERVATION TABLE:
S.No. Revolution of Revolution of Revolution of Average
gear G gear C Gear A revolutions of
gears C and
A
1. 1 0.0 2.0 1.0
2. 1 0.5 1.5 1.0
3. 1 1.0 1.0 1.0
4. 1 1.5 0.5 1.0
5. 1 2.0 0.0 1.0

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NEED OF DIFFERENTIAL WHEEL:
•To facilitate proper turning of vehicle.
•To prevent wear of tyres.

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DISADVANTAGES:
• Simple differential gears have one major disadvantage. If the inner
and outer wheels are on surfaces of unequal roughness, the wheel on
the smoother surface spins with a higher angular momentum.
• Since the differential splits the torque equally, the wheel on
rougher surface will decrease in angular momentum and hence the
vehicle will move at a very low speed or may not move at all.
Owing to these disadvantages certain
modifications have been adopted which gave rise different types in
differential workings.

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TYPES OF DIFFERENTIAL GEARS:
• Epicyclic differential:
An epicyclic differential uses epicyclic gearing to split and distribute
torque asymmetrically between the front and rear axles. For e.g- it is
used in Toyota Prius.
• Locking differential:
This when locked does not allows the wheels on a straight path to rotate
with different speed no matter what the traction is.
• Limited slip differential (LSD):
It limits the amount of slip with which one wheel can slip when it is on
slippery traction thus transferring more torque to other one which is
hopefully on good traction, while moving straight.