A differential is a device capable of transmitting torque and rotation through three shafts, almost always used in one of two ways.
Rear axle drives are the drives which employed for the rear axle the spring take the weight of the body.
JEEVAN B M
AUTOMOTIVE ELECTRONICS 1
Introduction of differential drive
Construction of differential drive
Principle and working of differential drive
Functions of differential.
Rear axial drive
Types of rear axil drive
Advantages and disadvantages of rear axial
AUTOMOTIVE ELECTRONICS 2
A differential is a device capable of transmitting torque and
rotation through three shafts, almost always used in one of
In one way, it receives one input and provides two outputs;
this is found in most automobiles
A differential is used to allow the wheels to spin at different
The function of the differential unit is to allow different
speeds to the two wheels
AUTOMOTIVE ELECTRONICS 3
AUTOMOTIVE ELECTRONICS 4
• When a car is moving along a bend in the road. Its inner wheel will
be rotating at a speed lower than that of its outer wheel
AUTOMOTIVE ELECTRONICS 7
inner wheel axle has been stopped by hand. But the
differential unit is still rotating. Thus the outer wheel can
now rotate at a faster speed. A similar arrangement is made
in the differential unit
AUTOMOTIVE ELECTRONICS 8
working of the differential
AUTOMOTIVE ELECTRONICS 9
At the time of straight road
• During the vehicle runs straight, the wheels of the rear
axle will be screened by the drive pinion through the
ring gear differential case, wheel-wheel differential gear
pinion shaft, side gear teeth is not spinning, remain to be
drawn into the ring gear rotation.
• Thus the spin on the wheel left and right alike
At the time of turning
• At the time of vehicle turning left prisoners left wheel is
bigger than the right wheel.
• If the differential case with the ring gear rotates the
pinion will rotate on its axis and also the movement
around the left side gear, so round the right hand side
gear increases, the side where the number of revolutions
of the gear which is 2 times round the ring gear.
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• Further reduces the rotations coming from the gear box
before the same are passed on to the rear axles.
• Changes the direction of axis of rotation of the power by
90o i.e. from being longitudinal to transverse direction.
• To distribute power equally to both the rear driving axles
when the tractor is moving in straight ahead direction.
• To distribute the power as per requirement to the driving
axles during turning.
AUTOMOTIVE ELECTRONICS 11
Rear axle drives are the drives which employed for the rear
axle the spring take the weight of the body.
In most of the front engine rear wheel drive cars, rear axles
are used for transmitting power from differential to driving
rear axle avoid bending load.
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• various forces and torques experienced by the rear axle
Driving trust(trust to be produced in the road due to humps)
Weight of the body(cause bending movement in the axle shaft)
The side way forces(moving along the curves)
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Many drives are used out of which two important ones
1. Hotchkiss drive.
2. Torque tube drive
In this case the springs besides the taking weight of
the body, also take the torque reaction, driving thrust
and the side thrust.
Due to torque reaction, the spring deflects as shown
in figure thus torque reaction is taken up by the
To take up the braking torque the springs would
deflect in the opposite direction.
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In this type spring takes body weight and side thrust only
The torque reaction and driving thrust are taken by
another member called torque tube
AUTOMOTIVE ELECTRONICS 17
Better handling in dry conditions.
More predictable steering in low traction condition(ie ice or
Less costly and easier maintenance.
Even weight distributions.
More difficult to master.
Decreased interior space.
• Higher purchase price
AUTOMOTIVE ELECTRONICS 18
Book of automotive mechanics by S SRINIVASAN
mechanismDIfferential drive mechanism
Book of automobile engineering by Dr. KIRPAL SINGH