Hydraulic Actuator | Types And Design

A hydraulic actuator is actually a motorized appliance, which utilize hydraulics for converting power into linear movement. The mechanical power that is generated is normally utilized for lifting or pressing things, which call for a lot of energy. Fluids have the capability of storing energy in the form of force, and it is also capable of transferring this power or energy as fluid flow, and it can also convert this stacked energy into motion. This is the principle on which a hydraulic actuator works. A hydraulic actuator use flowing fluid for transferring energy directly from the point of generation to the point of actuation. The needed fluid energy is produced in the shape of high pressure liquid by the way, of a pump that is driven by the means of electric motor. In most of the cases, heavy equipment relies on numerous actuators for proper functioning.

A hydraulic actuator comes in a number of piston types, designs and is very common for those applications that require loads of force for operating the valve. The movement of a hydraulic actuator is controlled by changes made in the amount of hydraulic liquid that is inside it. Earlier people utilized water as hydraulic liquid, but with the development in the filed of chemical engineering, now special oils have been designed, which are used for this specific purpose. When pressure is exerted on one end of a hydraulic actuator, then the fluid increases the pressure manifold and then converts it into mechanical movement. This is the mechanism, which helps these actuators in generating great power.

A typical hydraulic actuator comes in the piston-type and it comprise of a piston, hydraulic supply, return line, stem, spring, and a cylinder. The piston in a hydraulic actuator slides perpendicularly within the cylinder, and it divides the cylinder in two different compartments. The spring is in the top compartment and hydraulic oil is filled in the lower compartment. The return line and hydraulic supply are linked with the lower compartment and it enables the hydraulic fluid to flow from and to the lower compartment of the actuator. At the time of elating something, the main function that these perform is to crush, push plus stomp.

When the hydraulic fluid enters into the lower compartment, the pressure tends to augment. The generated pressure result into a force on the base of the actuator’s piston contradictory to force generated by the spring of a hydraulic actuator. This piston will start to move up, once the hydraulic force is more as compared to the spring force. On the other side, when the oil is exhausted the force will decrease as compared to the spring force and so the piston will move down as a result.

There are more than a few machines, which benefit from the way the hydraulic actuator work. A majority of the actuators act similar to the muscles of our arm, which can pull and push a machine. This provides enhanced flexibility in its movement. The principle on which a hydraulic actuator works is similar to the working of a pneumatic actuator. Both of these make use of motive force for overcoming spring force for moving the valve.  Another feature of a hydraulic actuator is that these can be designed with feature like fail-closed and fail-open. This will make them safer. Apart from being safe, other features that make hydraulic machines advantageous include agility and accuracy.

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