Rack and pinion


Rack and pinion

A rack and pinion is a pair of gears which convert rotational motion into linear motion. The circular "pinion" engages teeth on a flat bar - the "rack". Rotational motion applied to the pinion will cause the rack to move to the side, up to the limit of its travel.For example, in a rack railway, the rotation of a pinion mounted on a locomotive or a railcar engages a rack between the rails and pulls a train along a steep slope.

The rack and pinion arrangement is commonly found in the steering mechanism of cars or other wheeled, steered vehicles. This arrangement provides a lesser mechanical advantage than other mechanisms such as recirculating ball, but much less backlash and greater feedback, or steering "feel". The use of a variable rack was invented by Arthur E Bishop, [cite web|title=Rack and pinion variable ratio steering gear|publisher=Google Patent Search|url=http://www.google.com/patents?vid=USPAT3753378&id=bTEwAAAAEBAJ&dq=pinion+%2Bininventor:Arthur+ininventor:E+ininventor:Bishop&jtp=1|accessdate=2007-03-22] so as to improve vehicle response and steering "feel" on-centre, and that has been fitted to many new vehicles, after he created a hot forging process to manufacture the racks, thus eliminating any subsequent need to machine the form of the gear teeth.

For every pair of conjugate involute profile, there is a basic rack. This basic rack is the profile of the conjugate gear of infinite pitch radius."ANSI/AGMA 1012-G05", "Gear Nomenclature, Definition of Terms with Symbols".] what

A generating rack is a rack outline used to indicate tooth details and dimensions for the design of a generating tool, such as a hob or a gear shaper cutter.

External links

* [http://www.brockeng.com/mechanism/RackNPinion.htm Another animation] of the rack and pinion mechanism.

References


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Look at other dictionaries:

  • rack-and-pinion — [rak΄ən pin′yən] adj. designating or of an automotive steering system having a RACK1 (n. 5) and a pinion …   English World dictionary

  • rack-and-pinion — ► ADJECTIVE ▪ denoting a mechanism using a fixed cogged or toothed bar or rail engaging with a smaller cog …   English terms dictionary

  • rack and pinion — Mach., Auto. See under rack1 (def. 5a). * * * Mechanical device consisting of a bar of rectangular cross section (the rack), having teeth on one side that mesh with teeth on a small gear (the pinion). If the pinion rotates about a fixed axis, the …   Universalium

  • rack-and-pinion — /rak euhn pin yeuhn/, adj. of or pertaining to a mechanism in which a rack engages a pinion: rack and pinion steering. See illus. under rack1. [1900 05] * * * ˌrack and ˈpinion 7 [rack and pinion] adjective only before noun using a piece of… …   Useful english dictionary

  • rack and pinion — noun a wheel gear (the pinion) meshes with a toothed rack; converts rotary to reciprocating motion (and vice versa) • Hypernyms: ↑gear, ↑gear wheel, ↑geared wheel, ↑cogwheel * * * Mach., Auto. See under rack1 ( …   Useful english dictionary

  • rack-and-pinion — /rak euhn pin yeuhn/, adj. of or pertaining to a mechanism in which a rack engages a pinion: rack and pinion steering. See illus. under rack1. [1900 05] * * * …   Universalium

  • rack and pinion — See rack and pinion gearbox …   Dictionary of automotive terms

  • rack and pinion — rack′ and pin′ion n. aum mac See under rack I, 5), a) …   From formal English to slang

  • rack-and-pinion — /ræk ən ˈpɪnjən / (say rak uhn pinyuhn) noun 1. a system for the conversion of rotary to linear motion and vice versa, consisting of a pinion and a mated rack (rack1 def. 4). –adjective 2. of, using, or comprising such a system …   Australian English dictionary

  • rack and pinion — noun A pair of gears, consisting of a circular pinion that engages with the teeth of a flat bar, that converts rotational into linear motion; used in the steering mechanism of cars, and in some railways …   Wiktionary


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