Hydraulic cylinders are actuation devices that derive their power from a special fluid, usually a type of oil, under pressure. This produces linear motion; the energy stored in the pressurised hydraulic fluid is converted into a force that causes the cylinder to move in a linear direction. This power is then transferred to a mechanism that can perform a particular task. An example is an excavator, which is a machine that is very efficient at mechanical digging.
Generally speaking, hydraulic cylinders come as either single acting cylinders or double acting cylinders. A single acting cylinder has pressure applied from only one side. The cylinder top is returned to its original position through a strong spring that can act when the pressure acting on the hydraulic fluid is stopped and released. In a double acting cylinder, pressure on the fluid can be applied from each end. There are two types of double acting cylinders: single rod ended, and double rod ended.
One of the most robust hydraulic cylinders available is the Bosch Rexroth. These industrial hydraulic cylinders are built to the highest standards and can operate efficiently in the toughest conditions. The Bosch Rexroth is available as either mill type hydraulic cylinders or tie rod hydraulic cylinders. Mill type hydraulic cylinders are best suited for heavy duty work where the demands are many and the need for strength and reliability is paramount. Tie rod hydraulic cylinders are ideal where space is at a premium. This type is used extensively in the automotive industry, for example.
Telescoping cylinders, or multistage hydraulic cylinders, can have up to six stages. This type of cylinder can be single action or double action, and are found in application that have a minimised area. These cylinders have a long stroke. They can typically be seen used in forklift and cranes, for example.
Hydraulic cylinders need a power source, and this can be from an internal combustion engine, either petrol or diesel driven, an electric motor, or even a manual pump powered by hand or foot. As hydraulic cylinders can exert an extremely powerful force in a relatively confined area, they are particularly useful in a wide range of applications where size and efficiency are important factors. The hydraulic cylinders produced by Bosch Rexroth are especially robust and manufactured to a high specification.
