Bellows cylinders function both as driving and pneumatic spring components and fall under the category of diaphragm actuators. The pneumatic actuator does not have a piston rod, but the simple design consists of two metal plates with a ribbed rubber bellows. The large force is generated directly by the pressure on a relatively large surface of the end faces. A spring return is not required, as the return is usually effected by the weight of the load. A major advantage of bellows cylinders is their particularly low installation height compared to cylinders and their ease of movement.
This means that larger axis offsets and angular rotations of up to 20° are also possible. The stick-slip effect, which is often a problem with conventional cylinders, also does not occur with bellow cylinders. Double bellows are intended for larger strokes.
They can be used with various media such as compressed air, gases, and liquids if the properties of the rubber are taken into account.
Festo bellows cylinders are the right solution for many applications in pneumatic actuator technology. They are available with diameters from 80 mm to 385 mm. Strokes of up to 230 mm are possible with these products. The max. load bearing capacity at 8 bar is 70 kN.