Gears

Gears are toothed wheels Gears are used to transmit motion Gears are also used to convert rotary motion to linear motion or visa versa Gears can be used to reduce or increase the torque Gears are found in watches, engines and toys Gears 

Driver Gear:When two gears are in mesh the gear with the power (connected to the shaft) is called the driver

 Pinion: When two gears are in mesh the smaller gear is called the pinion, and the gear which power is transmitted to is called the driven gear

 Racket: is a spur gear whose radius is at infinity 

 Gear ratio:
 The gear ratio is the ratio at which one gear rotates relative to the other and it is directly proportional to the diameter of the gears Diameter of driver gear = D Diameter of driven gear = d Gear ratio= D:d If the driver gear has a diameter of 200 and the driven gear has a diameter of 100 then the gear ratio will be 2:1 – The driven gear rotates twice as fast as the driver gear

Parts of a Gear Tooth :

•  Pitch Surface Is an imaginary cylindrical surface which contains the pitch circle of a gear.
•  Addendum Is the part of the tooth outside the pitch..
• Dedendum Is the part of the tooth inside the pitch surface..
• Flank Is the part of the tooth that comes into contact with other gears 
• Pitch Surface Is an imaginary surface at the top of the tooth
• Root Surface Is an imaginary surface at the bottom of the tooth 
• Top Land Is the part of the tooth between opposite flanks
• Bottom Land Is the part of the root surface between opposite flanks
• Tooth Trace Is the intersection between the pitch surface and the flank of the tooth 

Involute Curve: