Cylinder is a term used in technology , especially in mechanical engineering , for various machine elements or assemblies . The common feature is the design, at least approximately in the form of a (circular) cylinder , often designed as a hollow cylinder.
Use of the term
- a rotating part of machines, with which pressure is exerted on a workpiece or which gives the workpiece properties by changing its direction (e.g. in a calender or the rotary cylinder of a printing machine ), also known as a roller.
- the working element of a technical circuit, which is controlled by an actuator (often a valve ).
With motors or pumps
- the tubular chamber in which a piston moves, as used in piston pumps , steam engines and internal combustion piston engines. Such machines are called piston machines . Piston machines can have one or more cylinders; in double piston engines, cylinders with a common combustion chamber are counted as one. The stroke (the linear movement) of the piston in the cylinder of the piston machine can be converted into a rotating movement, for example a wheel or a crankshaft , by means of a connecting rod . Also the reverse, i.e. H. the conversion of a rotation into a translation is basically possible. In internal combustion engines , the cylinder opens into the crankshaft housing on one side, and is closed on the other side or can be closed by valves .
- In piston steam engines, the steam usually acts alternately on both sides of the piston, and the cylinder is closed on both sides. The steam supply is usually controlled via slides, but sometimes via valves.
- In counter-rotating engines , the cylinder liner is open on both sides. The working medium (gas or air, gasoline-air mixture, air for direct injection) is controlled via the inlet and outlet slots.
In linear technology
- electromechanical cylinders, which are also known as electromechanical lifting cylinders or electromechanical actuators . The basic principle of electromechanical lifting cylinders can also be found in so-called telescopic lifting columns (also: lifting columns or telescopic drives).
In fluid technology
- a drive unit for linear - rarely also rotating - movements. The movement of the piston is transmitted to the parts to be moved via the piston rod or magnetic frictional connection. The lead out of the piston rod from the pressure chamber must be sealed. A distinction must be made between single-acting and double-acting cylinders ( work is only done in one direction or in both directions). Cylinders in hydraulics or pneumatics are the two fluid elements