1. Gears

2. Gears
Gears are toothed wheels that are used to
transmit constant angular velocity ratio
between two shafts. These shafts can be
parallel, intersecting or non-intersecting.

3. Classifications
• Gears connecting parallel shafts (parallel axes
gears)
• Gears connecting intersecting shafts
(intersecting axes gears)
• Gears connecting neither parallel nor
intersecting shafts (nonintersecting axes
gears)

4. Spur Gear

5. Helical Gear

6. Herringbone Gear

7. Rack and Pinion

8. Internal Gear

9. Straight Bevel Gear

10. Spiral Bevel Gear

11. Crossed Helical Gears

12. Hypoid Gears

13. Worm and Worm Gear

14. Spur Gear
Spur gears are toothed wheel with radially
arranged teeth parallel to the shaft axis.

15. External Gear

16. Internal Gears

17. Spur Gear Nomenclature

18. Fundamental Law of Gearing
For a pair of gear to transmit constant angular
velocity ratio, the tooth profiles of these
mating gears must be designed in such a way
that the common normal (line n-n) or the line
of action passes through a fixed point P, or
also known as the pitch point, on the line of
centers.