Gerotor
Encyclopedia
Vacuum
In everyday usage, vacuum is a volume of space that is essentially empty of matter, such that its gaseous pressure is much less than atmospheric pressure. The word comes from the Latin term for "empty". A perfect vacuum would be one with no particles in it at all, which is impossible to achieve in...
. This vacuum creates suction
Suction
Suction is the flow of a fluid into a partial vacuum, or region of low pressure. The pressure gradient between this region and the ambient pressure will propel matter toward the low pressure area. Suction is popularly thought of as an attractive effect, which is incorrect since vacuums do not...
, and hence, this part of the cycle is where the intake is located. As a volume decreases compression occurs. During this compression period, fluids can be pumped, or compressed (if they are gaseous fluids).
Gerotor pumps are generally designed using a trochoid
Trochoid
thumb|290px|right|A [[cycloid]] generated by a rolling circleTrochoid is the word created by Gilles de Roberval for the curve described by a fixed point as a circle rolls along a straight line...
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
Pistonless rotary engine
A pistonless rotary engine is an internal combustion engine that does not use pistons in the way a reciprocating engine does, but instead uses one or more rotors, sometimes called rotary pistons...
. High pressure gas enters the intake area and pushes against the inner and outer rotors, causing both to rotate as the area 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. Mr. Myron F. Hill, who might be called the father of the gerotor, in his booklet "Kinematics of Gerotors," lists efforts by a Mr. Galloway in 1787, by Messrs. Nash and Tilden in 1879, by Mr. 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 mechanism with a one-tooth difference to provide displacement.Mr. 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 GEROTOR (meaning GEnerated ROTOR) and secured basic patents on gerotors.
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 pumpOil pumpOil pump may refer to:*A hydraulic pump, which pressurizes hydraulic fluid in a hydraulic system*An oil pump , a part of the lubrication system that pressurizes motor oil for distribution around the engine...
s - Fuel pumpFuel pumpA fuel pump is a frequently essential component on a car or other internal combustion engined device. Many engines do not require any fuel pump at all, requiring only gravity to feed fuel from the fuel tank through a line or hose to the engine...
s - High speed gas compressorGas compressorA gas compressor is a mechanical device that increases the pressure of a gas by reducing its volume.Compressors are similar to pumps: both increase the pressure on a fluid and both can transport the fluid through a pipe. As gases are compressible, the compressor also reduces the volume of a gas...
s - EngineEngineAn engine or motor is a machine designed to convert energy into useful mechanical motion. Heat engines, including internal combustion engines and external combustion engines burn a fuel to create heat which is then used to create motion...
s - Hydraulic motors
- Power steeringPower steeringPower steering helps drivers steer vehicles by augmenting steering effort of the steering wheel.Hydraulic or electric actuators add controlled energy to the steering mechanism, so the driver needs to provide only modest effort regardless of conditions. Power steering helps considerably when a...
units