Rack and pinion
From Wikipedia, the free encyclopedia
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[1] , so as to improve vehicle response and steering "feel" on-centre, and that has been fitted to many new vehicles, such as the 2008 Honda Accord, 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.[2]
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.[2]
For rack and pinion railways see Rack and pinion railway.
[edit] References
- ^ Rack and pinion variable ratio steering gear. Google Patent Search. Retrieved on 2007-03-22.
- ^ a b ANSI/AGMA 1012-G05, "Gear Nomenclature, Definition of Terms with Symbols".
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 | Image:Gears large.jpg |
| Gear shapes | Straight cut 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) | |
| See also | Ball screw • Leadscrew • Jackscrew • Belt drive • Chain drive • Gear manufacturing | |
es:Cremallera eo:Dentrelo fr:Crémaillère it:Cremagliera ja:ラック・アンド・ピニオン nl:Tandheugel pt:Cremalheira ru:Кремальера
