Hydraulic cylinders

A cylinder is a device that transforms the energy of a fluid (usually oil) under pressure into mechanical work. This work can be produced by linear or angular displacement (however, it is more appropriate to refer to actuators that provide several revolutions of rotation as motors).

Cylinders are generally made up of parts which are considered to be dimensionally stable and which move relative to one another. However, there are also cylinders consisting of envelopes that can be deformed by the effect of pressure. In most cases, a cylinder is supported by a frame and moves a mobile element (figure 1 ).

This definition could include steam, combustion and pneumatic engine cylinders, but the notion of a cylinder generally implies a relatively slow movement.

It's also easier to call a cylinder a complete component that can be placed on a machine (the boom cylinder on a crane, for example) rather than a component part, which is then called a cylinder (the feed cylinder on a grinding machine table, for example).

The aim of this article is to briefly describe the main parameters governing the construction and use of the various types of cylinders. Readers wishing to examine individual characteristics in greater detail can refer to specialist works in each discipline, and in particular to the author's .