GENERAL CATALOGUE API

Cylinders Technical data

Definition and main features

The pneumatic cylinder is an engine that uses pneumatic energy, transforming it into mechanical work by means of rectilinear movement. It is composed of a barrel, closed at the ends by two heads, within which a piston moves, separating two chambers. The piston is equipped with a rod that, when exiting through one or both of the heads, permits the exploitation of the force developed by the cylinder. The characteristic parameters of a cylinder are: Bore = internal diameter of the [ mm ] Stroke = working movement to be performed [ mm ] Diameter of the piston rod = closely correlated to the bore [ mm ] Number of actings = number of strokes per cycle during which work is performed. These may be either one (single acting); or two (double acting).

Operating pressure range [ bar ] Operating temperature range [ °C ] Translation velocity [ m/s ] Number of adjustable end cushionings Kinetic energy absorbed by the cushionings [ Nm ] Air consumption [ nl/min ] Theoretical force [ N ]

1 - CYLINDERS

Bore Ø

Pressure range P

Piston rod diameter d

Stroke c

A finite number of bores are available, all of which are standardized. The range goes from bores measuring just a few millimetres to those of 320 mm

This value is not very variable, due to technical- economical reasons. It covers the range 5 ÷ 7 bar. A system operating at 6 bar is considered optimized.

This is standardized for all the available bores.

The most frequently requested strokes are available in our warehouse. Any technically compatible stroke can be supplied in a short time. It is advisable to choose easily available strokes that are greater than the operating strokes, halting the stoke at the desired value by means of external mechanical stops, in order to obtain mechanical precision and greater durability of the cylinder.

Operating temperature range

Ambient temperature must not be such as to make the cylinder assume values outside the temperature range for which it was constructed. It is possible to construct cylinders that are resistant to very low or very high temperatures, using special materials. The catalogues always show the operating temperature range. The cylinder can also reach high temperatures due to particular conditions of use: in general, when the friction between the tube and the mobile apparatus increases greatly (e.g. due to high speeds with insufficient lubrication, the exhaustion of assembly lubrication or excessive compression of the air). The seals of the cylinder are the most short-lived component and those that are most sensitive to temperature.

Translation velocity v

It is advisable to adjust the translation velocity by means of the air discharge. The movement of the piston is fairly regular even with minimum velocities of 40 mm/s. The maximum velocity acceptable without additional lubrication to assembly lubrication, is equivalent to 1000 mm/s. Velocities of 2 ÷ 3 m/s can be reached with appropriate lubrication. For high velocities, as for high masses, the kinetic energy to be reabsorbed is excessive for the air cushionings. It is necessary to use external hydraulic cushionings of an appropriate size.

Theoretical force Ft

The theoretical force generated by a cylinder can be calculated by multiplying the actual area of the piston subjected to pressure by the operating pressure. For cylinders during pushing, the effective area of the piston corresponds to the bore: Ft = p F 2 p / 40 [ N ] F = bore [ mm ] P = operating pressure [ bar ] N.B.: the formula considers passages from bars to N/m 2 and from mm 2 to m 2 . For cylinders in traction, it is necessary to subtract the area of the rod from that of the piston: Ft = p (F 2 - d 2 ) p / 40 [ N ]

1.1.1