To study and analyse Rack and Pinion Mechanism and understand it's Functioning and application
Theory
Rack and pinion, mechanical device consisting of a bar of rectangular cross section (the rack), having teeth on one side that mesh with teeth on a small gear (the pinion). The pinion may have straight teeth or helical (twisted) teeth that mesh with teeth on the rack that are inclined to the pinion-shaft axis.
RACK AND PINION MECHANISM
If the pinion rotates about a fixed axis, the rack will translate; i.e., move on a straight path. Some automobiles have rack-and-pinion drives on their steering mechanisms that operate in this way.
If the rack is fixed and the pinion is carried in bearings on a table guided on tracks parallel to the rack, rotation of the pinion shaft will move the table parallel to the rack. On machine tools, rack-and-pinion mechanisms are used in this way to obtain rapid movements of worktables; the pinion shaft is usually rotated with a hand crank.
Application
Car Steering:
The system works by converting a revolving motion into linear motion. Most cars, small trucks, and SUVs come equipped with a rack and pinion system, rather than the recirculating ball steering found in larger trucks, larger SUVs, and other heavy-duty vehicles.
Railways:
Rack railways are mountain railways that use a rack built into the center of the track and a pinion on their locomotives. This allows them to work on steep gradients, up to 45 degrees, as opposed to conventional railways which rely on friction alone for locomotion. Additionally, the rack and pinion addition provides these trains with controlled brakes and reduces the effects of snow or ice on the rails.
Stairlifts:
All stairlifts contain a rack and pinion gear, with the gear allowing for upward movement in similar ways as above.
Actuators:
Actuators are machines that move various components, such as a pipeline transport system. In such a system, a rack and pinion gear help control the valves that the system requires for basic functioning.
Simulation Video
CAD Model
Mechanisms similar to Rack and Pinion
Recirculation Balls: The recirculating ball steering mechanism contains a worm gear inside a block with a threaded hole in it; this block has gear teeth cut into the outside to engage the sector shaft (also called a sector gear) which moves the Pitman arm.