GEAR BASICS

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GEAR BASICS
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Basics of Gears

• Used for gear reduction (multiplies torque)
• Change direction of rotation
• Gears need lubrication
• Type of lube viscosity depends on application

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Spur Gears

• Most common type
• Straight teeth, mounted on parallel shafts
• Do not handle great stress
• Noisy!

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Helical Gears

• Most common found in vehicles
• Gear teeth cut on an angle
• Smooth quiet operation
• Easily handles high thrust loads
• Can be mounted on perpendicular shafts, changing
  the rotating angle 90 degrees

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Bevel Gears

• Allows for rotation to change direction
• Straight, spiral, hypoid tooth designs
• Hypoid is used in drive axles, quiet, can handle
  tremendous loads

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Worm Gears

• Used when large gear reductions are needed
• The worm can easily turn the gear, gear cannot
  turn the worm
• Shallow angle high friction between teeth

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Rack Pinion

• Used to convert rotation into linear motion

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Rack Pinion Steering Gear
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Planetary Gearsets

• 3 main parts
• Sun gear
• Planet gears the carrier
• Ring gear
• Each of these can be an input, output or held
  stationary
• Provides tremendous torque multiplication

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Involute Gear Profile

• Straight tooth gears tend slow down speed up
• Special gear tooth shape compensates for this
• Provides a smooth power flow