A gerotor is a

positive displacement pump A pump is a device that moves fluids (liquids or gases), or sometimes slurries, by mechanical action, typically converted from electrical energy into hydraulic energy. Pumps can be classified into three major groups according to the method they ...

. The name ''gerotor'' is derived from "generated

rotor Rotor may refer to: Science and technology Engineering * Rotor (electric), the non-stationary part of an alternator or electric motor, operating with a stationary element so called the stator *Helicopter rotor, the rotary wing(s) of a rotorcraft ...

". A gerotor unit consists of an inner and outer rotor. The inner rotor has ''n'' teeth, while the outer rotor has ''n''+1 teeth; with ''n'' defined as a

natural number In mathematics, the natural numbers are those numbers used for counting (as in "there are ''six'' coins on the table") and ordering (as in "this is the ''third'' largest city in the country"). Numbers used for counting are called '' cardinal ...

greater than or equal to 2. The axis of the inner rotor is offset from the axis of the outer rotor and both rotors rotate on their respective axes. The geometry of the two rotors partitions the volume between them into ''n'' different dynamically-changing volumes. During the assembly's rotation cycle, each of these volumes changes continuously, so any given volume first increases, and then decreases. An increase creates a

vacuum A vacuum is a space devoid of matter. The word is derived from the Latin adjective ''vacuus'' for "vacant" or " void". An approximation to such vacuum is a region with a gaseous pressure much less than atmospheric pressure. Physicists often ...

. This vacuum creates

suction Suction is the colloquial term to describe the air pressure differential between areas. Removing air from a space results in a pressure differential. Suction pressure is therefore limited by external air pressure. Even a perfect vacuum cannot ...

, and hence, this part of the cycle is where the inlet is located. As a volume decreases compression occurs. During this compression period, fluids can be pumped, or, if they are gaseous fluids, compressed. Gerotor pumps are generally designed using a

trochoid In geometry, a trochoid () is a roulette curve formed by a circle rolling along a line. It is the curve traced out by a point fixed to a circle (where the point may be on, inside, or outside the circle) as it rolls along a straight line. If the ...

al inner rotor and an outer rotor formed by a circle with intersecting circular arcs. A gerotor can also function as a

pistonless rotary engine A pistonless rotary engine is an internal combustion engine that does not use pistons in the way a reciprocating engine does. Designs vary widely but typically involve one or more rotors, sometimes called rotary pistons. Although many differ ...

. High pressure gas enters the intake and pushes against the inner and outer rotors, causing both to rotate as the volume between the inner and outer rotor increases. During the compression period, the exhaust is pumped out.

History

At the most basic level, a gerotor is essentially one that is moved via fluid power. Originally this fluid was water, today the wider use is in hydraulic devices. Myron F. Hill, who might be called the father of the Ge-rotor, in his booklet "Kinematics of Ge-rotors," lists efforts by Galloway in 1787, by Nash and Tilden in 1879, by Cooley in 1900, by Professor Lilly of Dublin University in 1915, and by Feuerheerd in 1918. These men were all working to perfect an

internal gear A gear is a rotating circular machine part having cut teeth or, in the case of a cogwheel or gearwheel, inserted teeth (called ''cogs''), which mesh with another (compatible) toothed part to transmit (convert) torque and speed. The basic ...

mechanism by a one-tooth difference to provide displacement. Myron Hill made his first efforts in 1906, then, in 1921, gave his entire time to developing the gerotor. He developed a great deal of geometric theory bearing upon these rotors, coined the word GE-ROTOR (meaning "Generated Rotor") and secured basic patents on GE-ROTOR. Gerotors are widely used today throughout industry, and are produced in a variety of shapes and sizes by a number of different methods.

Uses

* Oil pumps * Fuel pumps * High speed

gas compressor A compressor is a mechanical device that increases the pressure of a gas by reducing its volume. An air compressor is a specific type of gas compressor. Compressors are similar to pumps: both increase the pressure on a fluid and both can tran ...

s *

Engine An engine or motor is a machine designed to convert one or more forms of energy into mechanical energy. Available energy sources include potential energy (e.g. energy of the Earth's gravitational field as exploited in hydroelectric power ...

s * Hydraulic motors *

Power steering A power steering is a mechanical device equipped on a motor vehicle that helps drivers steer the vehicle by reducing steering effort needed to turn the steering wheel, making it easier for the vehicle to turn or maneuver at lower speeds. Hydra ...

units *

Limited-slip differential A limited-slip differential (LSD) is a type of differential that allows its two output shafts to rotate at different speeds but limits the maximum difference between the two shafts. Limited-slip differentials are often known by the generic tr ...

References

*https://www.academia.edu/10200507/Gerotor_Modeling_with_NX3

External links

Cascon Inc.

Nichols Portland LLC

Step by step drawing
* {{cite news , author= Jennifer Kho , title= Electricity from Waste Heat: Ener-G-Rotors' system harvests energy at lower temperatures , date= November 21, 2008 , work=

Technology Review ''MIT Technology Review'' is a bimonthly magazine wholly owned by the Massachusetts Institute of Technology, and editorially independent of the university. It was founded in 1899 as ''The Technology Review'', and was re-launched without "The" in ...

, publisher=

Massachusetts Institute of Technology The Massachusetts Institute of Technology (MIT) is a private land-grant research university in Cambridge, Massachusetts. Established in 1861, MIT has played a key role in the development of modern technology and science, and is one of th ...

(MIT) , url= https://www.technologyreview.com/2008/11/21/96006/electricity-from-waste-heat/ , accessdate= 2021-01-30 Gas compressors Engine technology

History

Uses

See also

References

External links