Gear - Wikipedia, the free encyclopedia
1 History 1.1 History of the differential gear 1.2 History of other gears 2 Comparison with drive mechanisms 3 Types 3.1 External vs internal gears 3.2 Spur 3.3 Helical 3.3.1 Skew gears 3.4 Double helical 3.5 Bevel 3.6 Spiral bevels 3.7 Hypoid 3.8 Crown 3...