Rear axle is the last member of power train. In most of
automobiles, real axle is the driving axle. It lies between the driving wheels
and the differential gear and transmit power from the differential to the driving
wheels. It consists of two half shaft connected to the differential gear, one
for one wheel. The inner end of the each half shaft connected to the sun gear
of the differential and the outer end to the wheel. The rear axle and
differential gear are completely encloses in a housing which protecting them
from water, dust and injury.
Function of rear axle:
The rear axle mainly performs following two functions.
- 1. It carries the weight of the vehicle.
- 2. It rotates and transmits the power from the engine to the wheels.
Classification of rear axle:
Rear axle classified by two methods.
1. According to the design of axle:
(A.) Banjo axle:
This type of axle is a single shaft and final drive assembly
is carried in a separate casing which is bolted to the axle housing. The banjo
construction is often used for smaller and lighter vehicle.
(B.) Split axle:
In this type of axle split shaft are used with the central
housing contain the differential gear and it is fitted with a tube on each side
to carry the half axles and bearing.
2. According to the method of supporting:
(A.) Half floating rear axle:
In this axle the bearing which support the axle, are inside
the casing. The axle of the wheel is at the center of the axle casing.
The whole weight of the vehicle is first transmitted to the
suspension spring then to the axle casing, rear axle, wheel and ground.
(B.) Three quarter floating rear axle:
In this axle bearing are on the outer side of casing between
the wheel and the axle casing. The wheels are fitted at the end of the axle by
means of a key, bolt or nut.
The weight of the vehicle is supported partly by the axle casing
and partly by the axle. The main advantage of this type of axle over the half
floating axle is that the major part of the load is taken by the axle casing and
not by axle. Axle only takes care of the rotating and transmits the power.
(C.) Full floating rear axle:
In this type of axle bearing are on the outer side of casing
between the wheel and the axle casing. The axle is not supported by the bearing
at entire end and its position is maintained by the way that it is supported at
both ends. The wheels are fitted at the end of the axle by means of a key, bolt
or nut.
Thus the entire weight of the vehicle is supported by the
wheel and axle casing. The axle is relieved of all strain caused by the weight
of the vehicle on end thrust. It transmits only driving torque.
Today we have discussed about rear axle. If you have any query regarding this article ask by commenting below.