pinion
{{Short description|Round gear, usually the smaller of two (meshed) gears}}
{{About|a type of 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.
Applications
= Drivetrain =
Drivetrains usually feature a gear known as the pinion, which may vary in different systems, including
- the typically smaller gear in a gear drive train (although in the first commercially successful steam locomotive—the Salamanca—the pinion was rather large).{{cite book|isbn=1-55589-846-7|oclc=65562739|title=Gear Nomenclature, Definition of Terms with Symbols|year=2005|pages=72|id=ANSI/AGMA 1012-G05|publisher=American Gear Manufacturers Association}} In many cases, such as remote controlled toys, the pinion is also the drive gear for a reduction in speed, since electric motors operate at higher speed and lower torque than desirable at the wheels. However the reverse is true in watches, where gear trains commence with a high-torque, low-speed spring and terminate in the fast-and-weak escapement.
- the smaller gear that drives in a 90-degree angle towards a crown gear in a differential drive.
- the small front sprocket on a chain driven motorcycle.
- the clutch bell gear when paired with a centrifugal clutch, in radio-controlled cars with an engine (e.g., nitro).{{cite web| url = http://www.nitrorc.com/articles/clutch.html| archive-url = https://web.archive.org/web/20020127002635/http://www.nitrorc.com/articles/clutch.html| url-status = dead| archive-date = January 27, 2002| title = Clutch Tuning| author = Eric Perez| publisher = NitroRC.com| access-date = 2010-01-29}}
= Rack and pinion =
Image:Rack and pinion animation.gif
{{Main|Rack and pinion}}
In rack and pinion systems, the pinion is the round gear that engages and moves along the linear rack.