1. GEARS

2. Presentation Objectives
Identify parts of the gear trainer
Identify gears
Identify gear terminology
Identify tooth terminology
Identify gear purpose
Determine RPM
Determine torque

3. Gear Trainer

4. What is a Gear?
A gear is a toothed wheel

5. Spur Gear

6. Worm Gear Drive

7. Bevel Gears

8. Crossed Helical Gear

9. Harmonic Gear

10. Planetary Gear Train

11. Car Differential

12. Car Differential

13. Gear Terminology Gear - 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)

14. 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.

15. Gear Terminology Compound Gear Train Simple Gear Train Worm Gear
Miter Gear

16. Spur Gear Terminology
Involute Profile

17. Spur Gear - Tooth Parts

18. Gear Tooth Size Called Diametral Pitch

19. Purpose of a Gear Energy Transmission
In the proper combination can be used to increase or decrease speed and torque

20. 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)

21. Determining Gear Rpm Driving Gear Teeth Driven Gear Teeth
X Driving Gear RPM = RPM of Driven gear

22. 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.

23. 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

24. Importance Modern Multi Speed Bicycles Automobiles
Construction Equipment

25. Also Recreation (fishing) Timing Gears
Efficient Transportation (sprocket system)

26. Car 3 Speed Transmission

27. 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.

28. 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.