In a piston engine, the main bearings are the bearings on which the crankshaft rotates, usually plain or journal bearings. The bearings hold the crankshaft in place and prevent the forces created by the piston and transmitted to the crankshaft by the connecting rods from dislodging the crankshaft, instead forcing the crank to convert the reciprocating movement into rotation.
A cylinder is the central working part of a reciprocating engine or pump, the space in which a piston travels. Multiple cylinders are commonly arranged side by side in a bank, or engine block, which is typically cast from aluminum or cast iron before receiving precision machine work.
A double acting cylinder uses hydraulic power to both extend and retract. You can tell if a cylinder is double acting by looking at the number of ports. See the image below as an example. In contrast, a single acting cylinder has an A port for running the piston down by pressure from the pump but is retracted with an internal spring.
Mechanically coupled slide Magnetically coupled slide; Mechanically coupled slides The piston is moved in the cylinder barrel using compressed air. The cylinder barrel is open on one side across its entire length, so that a mechanical connection can be established between the piston and slide.
In a piston engine, a piston rod joins a pistonto the crosshead and thus to the connecting rod that drives the crankshaft or (for steam locomotives) the driving wheels. Internal combustion engines, and in particular all current automobile engines, do not generally have piston rods.
In contrast, a single acting cylinder has an A port for running the piston down by pressure from the pump but is retracted with an internal spring. See the image below as an example. A double acting cylinder has pressing and pulling power and is generally controlled with a joy stick control.