A swashplate, also known as slant disk, was invented by
Anthony Michell
Anthony George Maldon Michell FRS (21 June 1870 – 17 February 1959) was an Australian mechanical engineer of the early 20th century.
Early life
Michell was born in London while his parents were on a visit to England from Australia to which th ...
in 1917. It is a
mechanical engineering
Mechanical engineering is the study of physical machines that may involve force and movement. It is an engineering branch that combines engineering physics and mathematics principles with materials science, to design, analyze, manufacture, and ...
device used to translate the motion of a rotating shaft into
reciprocating motion
Reciprocating motion, also called reciprocation, is a repetitive up-and-down or back-and-forth linear motion. It is found in a wide range of mechanisms, including reciprocating engines and pumps. The two opposite motions that comprise a single r ...
, or vice versa. The working principle is similar to
crankshaft
A crankshaft is a mechanical component used in a piston engine to convert the reciprocating motion into rotational motion. The crankshaft is a rotating shaft containing one or more crankpins, that are driven by the pistons via the connecting ...
,
Scotch yoke
The Scotch Yoke (also known as slotted link mechanism) is a reciprocating motion mechanism, converting the linear motion of a slider into rotational motion, or vice versa. The piston or other reciprocating part is directly coupled to a sliding yo ...
, or wobble/nutator/Z-crank drives, in engine designs. It was originally invented to replace a crankshaft, and is one of the most popular concepts used in crankless engines.
Construction
A swashplate consists of a disk attached to a shaft. If the disk were aligned perpendicular to the shaft, then rotating the shaft would merely turn the disk with no reciprocating (or ''swashplate'') effect. But instead the disk is mounted at an oblique angle, which causes its edge to appear to describe a path that oscillates along the shaft's length as observed from a non-rotating point of view away from the shaft. The greater the disk's angle to the shaft, the more pronounced is this apparent linear motion. The apparent linear motion can be turned into an actual linear motion by means of a follower that does not turn with the swashplate but presses against one of the disk's two surfaces near its circumference. The device has many similarities to the
cam
Calmodulin (CaM) (an abbreviation for calcium-modulated protein) is a multifunctional intermediate calcium-binding messenger protein expressed in all eukaryotic cells. It is an intracellular target of the secondary messenger Ca2+, and the bind ...
.
Uses
The
swashplate engine uses a swashplate in place of a crankshaft to translate the motion of a piston into rotary motion.
Internal combustion engine
An internal combustion engine (ICE or IC engine) is a heat engine in which the combustion of a fuel occurs with an oxidizer (usually air) in a combustion chamber that is an integral part of the working fluid flow circuit. In an internal combus ...
s and
Stirling engine
A Stirling engine is a heat engine that is operated by the cyclic compression and expansion of air or other gas (the ''working fluid'') between different temperatures, resulting in a net conversion of heat energy to mechanical work.
More specif ...
s have been built using this mechanism. Duke Engines has been working on such a platform since 1993.
The
axial piston pump drives a series of pistons aligned parallel with a shaft through a swashplate to pump a fluid.
[Harris et al] A common example of a swashplate application in a fluid pump is the
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 transp ...
of a present-day
automobile air conditioning
Automobile air conditioning systems use air conditioning to cool the air in a vehicle.
History
A company in New York City in the United States first offered installation of air conditioning for cars in 1933. Most of their customers operated limo ...
system. By varying the angle of the swashplate, the pistons' stroke (and, therefore, the compressor's cooling capacity) can be dynamically adjusted.
A
helicopter swashplate is a pair of plates, one rotating and one fixed, that are centered on the main rotor shaft. The rotating plate is linked to the rotor head, and the fixed plate is linked to the operator controls. Displacement of the alignment of the fixed plate is transferred to the rotating plate, where it becomes reciprocal motion of the rotor blade linkages. This type of differential pitch control, known as cyclic pitch, allows the helicopter rotor to provide selective lift in any direction. The swashplate can also transfer a combined static pitch increase to all rotor blades, which is known as collective pitch.
Nutating flowmeters and pumps have similar motions to the wobble of a swashplate, but do not necessarily transform the motion to a reciprocating motion at any time.
Active electronically scanned array
An active electronically scanned array (AESA) is a type of phased array antenna, which is a computer-controlled array antenna in which the beam of radio waves can be electronically steered to point in different directions without moving the an ...
(AESA) radars are flat plates that can scan up to sixty degrees in any direction from directly ahead of them. By mounting an AESA radar on a swashplate, the swashplate angle is added to the electronic scan angle. The typical swashplate angle chosen for this application is 40 degrees, enabling the radar to scan a total angle of 200 degrees out of 360.
Gripen NG AESA Radar
/ref>
See also
*
Notes
References
*
External links
*YouTube video of a swashplate in action
{{Piston engine configurations, state=uncollapsed
Linkages (mechanical)