Hypoid

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A hypoid is a type of spiral bevel gear whose axis does not intersect with the axis of the meshing gear. The shape of a hypoid gear is a revolved hyperboloid, whereas the shape of a spiral bevel gear is normally conical. The hypoid gear places the pinion off-axis to the crown wheel (ring gear) which allows the pinion to be larger in diameter and have more contact area. In most passenger cars, the pinion is offset to the bottom of the crown wheel. This provides for longer tooth contact and allows the propeller shaft that drives the pinion to be lowered, reducing the "hump" intrusion in the passenger compartment floor.

A hypoid gear incorporates some sliding and can be considered halfway between a straight-cut gear and a worm gear. Special gear oils are required for hypoid gears because the sliding action creates extreme pressure between the teeth.

[edit] See also

• Offset (gears)

v • d • e Gears Gear systems Spur gear systems • Worm gear • Rack and pinion • Epicyclic (planetary) gearing • Sun and planet gear • Harmonic drive • Cycloidal drive • Non-circular gear Gear shapes Spur gear • Bevel gear • Helical gear • Hypoid gear Geartooth profiles Involute • Cycloid Gear mechanics Transmission • Differential • Gear coupling • Gear train • Bicycle gearing • Continuously variable transmission • Offset (gears) Examples Freewheel In Bicycles: Cassette (bicycle part) • Derailleur gears • Fixed-gear bicycle • Hub gear • Shaft-driven bicycle • Sprocket See also Ball screw • Leadscrew • Jackscrew • Belt drive • Chain drive • Gear manufacturing

[edit] References