Forging new generations of engineers. GEARS Presentation Objectives Identify parts of the gear...
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Transcript of Forging new generations of engineers. GEARS Presentation Objectives Identify parts of the gear...
Forging new generations of engineers
GEARS
Presentation Objectives
• Identify parts of the gear trainer
• Identify gears• Identify gear terminology• Identify tooth terminology• Identify gear purpose• Determine RPM• Determine torque
Gear Trainer
What is a Gear?• A gear is a toothed wheel
Spur Gear
Worm Gear Drive
Bevel Gears
Crossed Helical Gear
Harmonic Gear
Planetary Gear Train
Car Differential
Car Differential
Gear TerminologyGear - A toothed wheel
Drive Gear - The gear which produces the input
Driven Gear - The gear which produces the output
Chain Drive - Combines the sprocket and chain that mesh together to produce a positive mechanical force
Gear Ratio - The description of the mechanical advantage obtained through the use of rotating devices
Mechanical Advantage - An output increase determined by comparing the input revolutions per minute (RPM) to the output revolutions per minute (RPM)
Gear Terminology
Pulley - A wheel used to transmit power by means of a band, belt, cord, or rope
Torque - The turning effort that causes something to rotate. If torque produces rotation, then work is done
Wheel - A lever that is rotated 360 degrees around an axle
Work - The ability of force to travel through a distance
Gear Train - A series of two or more meshed gears used to increase or decrease the RPM, torque, or direction of rotation of the output gear.
Gear Terminology
Spur Gear Terminology
Involute Profile
Spur Gear - Tooth Parts
Gear Tooth Size Called Diametral Pitch
Purpose of a Gear
• Energy Transmission• In the proper combination can be used to
increase or decrease speed and torque
Gear Rotations
With two gears, the output of the driven gear will rotate in the opposite direction of the drive gear
With more than two gears, every other gear will rotate in the same direction (ie. Gears 1, 3, 5 will rotate clockwise and gears 2, 4 will rotate counter clockwise)
Determining Gear Rpm
Driving Gear Teeth
Driven Gear TeethX Driving Gear RPM = RPM of Driven gear
What Is Torque?
• The turning effort (measured in inch-pounds or foot-pounds) that causes something to rotate. When torque produces rotation, then work is done.
Determining Torque
Power Out = Power In
1HP at 100 rpm=1/2 HP at 200 rpm
1 HP at 200 rpm = 2 HP at 100 rpm
Importance
• Modern Multi Speed Bicycles
Automobiles
Construction Equipment
Also
Timing Gears
Recreation (fishing)
Efficient Transportation (sprocket system)
Car 3 Speed Transmission
Gear Facts• The rpm of the larger gear is always slower than
the rpm of the smaller gear.• Mating gears always turn in the opposite
direction.• Gears locked together on the same shaft will
always turn in the same direction and at the same rpm.
• Mating gears always have the same size teeth (diametral pitch).
• The gear ratio between mating gears is the ratio between the number of teeth, the pitch diameters and the rpms.
Gear Review
• What is a gear?
• Name 4 different types of gears.
• What is torque and rpm?
• What is diametral pitch & how is it shown?
• List 10 places where gears are used.