Gears Classifications 

 Parallel Shaft Gears Types :
 Spur Gear / Internal gear / Helical Gear / Gear Rack
 Intersecting Shaft Gears Types:
 Straight Bevel Gear / Spiral Bevel Gear / Miter Gear / Face Gear
 Non-parallel and Non-intersecting Shaft Gears Types:
 Worm gear / Hypoid Bevel Gear / Screw Gear