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Pinion and annular gear

A pinion is a round gear—usually the smaller of two meshed gears—used in several applications, including drivetrain and rack and pinion systems.



Drivetrains usually feature a gear known as the pinion, which may vary in different systems, including

Rack and pinion[edit]

Rack and pinion animation

In rack and pinion systems, the pinion is the round gear that engages and moves along the linear rack.

See also[edit]


  1. ^ Gear Nomenclature, Definition of Terms with Symbols. American Gear Manufacturers Association. 2005. p. 72. ISBN 1-55589-846-7. OCLC 65562739. ANSI/AGMA 1012-G05.
  2. ^ Eric Perez. "Clutch Tuning". Retrieved 2010-01-29.[dead link]