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Rack and Pinion
Most most motor vehicles are
steered using a steering wheel (the first cars used a tiller which was a
lever system). The movement of the steering wheel,
which is rotational, has to be converted into a linear motion in order
to turn the wheels of the vehicle. The solution to the problem of
converting a rotational force into a linear force was solved by the
introduction of 'Rack and Pinion' steering system. At the end of the
steering column is a gear called a pinion, The pinion sits on the rack
which is a horizontal rectangle gear. The pinion sits on top of the
teeth of the rack and when the steering wheel is turned, the pinion
moves the rack in the same direction of the steering wheel. The rack is
connected at each end to tie rods which connect to the wheels and when
the steering wheel is rotated, the wheels are moved in the required
direction.
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Power Steering
Most new cars tend
to be fitted with 'Power Steering'. Power Steering including
Electric systems and Hydraulic systems aid the driver's ability to
turn the steering wheel. Using eclectic motors and computer software
programs, Electric Systems detect the actions of the driver and
amplify the rotation and torque of the driver's steering. |
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Using a rotary
vane pump, Hydraulic systems use hydraulic fluids and valves to
increase the pressure on the steering mechanisms which in turn
create torque in order to turn the car's wheels. |
 Driveshafts |
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The typical
car has many moving parts and systems, some of which although
important are not essential for the operation of the car. One
critical system in the car is obviously the movement of the wheels.
The initial problem with the combustion engine is how to transfer
the power from the engine to the car’s wheels. In order for the
transfer of power from the engine through the transmission to the
movement of its wheels, a rotational force is required. Cars use
drive shafts to transfer torque to the wheels thus enabling movement
of the car. |
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Torque can be best
described as a rotational force and when we think of torque
wrenches, these are tools that are designed to measure very
precisely the amount of rotational force needed for building and
rebuilding engines when torque measurements need to be exact.
In the past many engines transferred power through systems of belts
and or chains. For example the transfer of the pedal rotations from
the cyclist to the wheel of a bicycle is typically transferred
through a chain which rotates the wheel. The use of chains and belts
in a motor car would be too cumbersome and a stronger more rigid
system that could deal with the twisting and parallel forces exerted
on the system of transfer which is called torsion and shear stress
would be required.
Drive shafts are cylindrical in shape and are usually either all
steel or all aluminium with aluminium becoming the industry standard
although carbon fibre drive shafts are becoming increasingly
popular. |
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