1. Engineering 1040: Mechanisms & Electric Circuits Fall 2011 Power Transmission Systems: Gear Drives

2. Gear Terminology

3. Gear Animation

4. Factors considered in gear selection Pitch circle diameter Number of teeth Face Width Material used to manufacture the gear Style of hub, bore, etc

5. A Gear Spur Gear Catalog

7. Involute Circle The curve most commonly used for gear-tooth profiles is the involute of a circle.

8. Gear Relationships

9. Gear Problems (Interference)

10. Gear Problems (Backlash)

11. Gear Types (1) Spur Gears – Simplest of the gears – Used to connect parallel shafts – Simple shape – Low cost – No thrust loads from teeth engagement Helical Gears – Smooth operation as it results in gradual gear engagement – Could connect parallel or non parallel shafts – Higher thrust loads from teeth reaction forces

12. Gear Types (2) Bevel gear – Could be used to connect two shafts that are at an angle – The teeth may be straight or helical – Two gear have conical surfaces Worm & wheel – Very low transmission ratios – High torque transmission – High Friction loses

13. Gear Types (3) Rack & pinion – Converts the rotational motion into linear motion – Could have straight or bevel teeth – Provides less backlash – Greater feedback