Machine Elements:

1
Machine Elements

• Rack Pinion

Carmen
2
Definition

• Rack and Pinion

• - A single gear, the pinion, meshes with a
  sliding toothed rack. Of two mating gears, the
  one with the smaller number of teeth is called
  the pinion. The rack is a gear with teeth spaced
  along a straight line, and suitable for
  straight-line motion. This combination converts
  rotary motion to back and forth motion.

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Formula
Source-http//www.globalspec.com/Oriental
MotorUSA/ref/Sizing_Formulas

• ROTATION results when an unbalanced torque acts
  on a body producing an angular acceleration. The
  torque to accelerate is the product of the body's
  moment of inertia about its axis of rotation (J)
  and the angular acceleration (a).
• Rotation J a

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Formulas (Cont.)

• The steering ratio is the ratio of how far you
  turn the steering wheel to how far the wheels
  turn.
• Example (car steering)
• If one complete revolution (360 degrees) of the
  steering wheel results in the wheels of the car
  turning 20 degrees, then the steering ratio is
  360 divided by 20, or 181.

5
Source- http//auto.howstuff works.com/steering2.h
tm
Everyday Applications

• Rack and pinion gears from a household scale.

• Rack and pinion from cars steering
  column.

6
Source-http//www.technology student.com/gears1/ge
ars 4.htm
A Practical Example

• A large gear wheel, called the pinion, is added
  to the center of the train and an extra track,
  that has teeth, called the rack is added to the
  track. As the train approaches a steep hill or
  slope the gear is lowered to the track and it
  meshes with the rack. The train does not slip
  backwards but it is pulled up the steep slope.

7
Drilling Machine
  As the handle is turned the table moves up and down the central pillar of the drill. This makes it easy to move the table and takes the minimum  of effort.                                                                  

Source- http//www.technology student.com/gears1/d
rlgear.htm