Linear actuators are designed to drive parts of machines and mechanisms in a linear progressive motion. The drive converts electrical, hydraulic energy or compressed gas energy into motion or force. This article presents an analysis of hydraulic linear actuators, their advantages, and their disadvantages.
So how a linear actuator work?
Table of Contents
According to the principle of operation, linear actuators can be divided into:
– electric;
– pneumatic;
– hydraulic.
Electric linear actuators convert electrical energy into mechanical energy. As an engine, they use either a rotating or linear electric motor. The rotating electric motor moves the rod using a mechanical transducer, for example utilizing a ball screw or roller screw.
Pneumatic and hydraulic actuators are mechanical converters and represent a kind of insert (pneumatic or hydraulic) between the engine and the actuator.
Pneumatic linear actuators have a piston inside a hollow cylinder. Pressure from an external compressor or hand pump moves the piston inside the cylinder. With increasing pressure, the piston moves along the axis, creating a linear force. The piston returns to its initial position utilizing a spring or compressed gas supplied from the other side of the piston. Hydraulic linear actuators work the same way pneumatic actuators do, but practically incompressible fluid supplied by the pump moves the rod better than the compressed air.
Hydraulic Actuators
Advantages:
1. Hydraulic actuators are suitable for tasks requiring high forces. They can create a force 25 times bigger than pneumatic actuators of the same size. They operate at pressures up to 27 MPa.
2. Hydraulic motors have a high power rating per volume.
3. Hydraulic actuators can keep the force and torque constant without the pump supplying additional fluid or pressure, since the fluids, unlike gas, are practically not compressed.
4. Hydraulic actuators can be located at a considerable distance from pumps and motors with minimal loss of power.
Disadvantages:
1. Like pneumatic actuators, fluid loss in hydraulic actuators leads to less efficiency. In addition, leakage of liquid leads to contamination and potential damage to several located components.
2. Hydraulic actuators require many accompanying components, including a fluid reservoir, motors, pumps, bleeding valves, heat exchangers, etc. In connection with this such drives are difficult to locate.
When a particular installation, machine, or part of the device performs any straight-line movements during operation, the natural choice for you will be a compact hydraulic linear actuator. This is especially true in cases where a reliable drive is required, which in mechanical or pneumatic design would be too complicated or expensive.
Conclusion
Hydraulic linear actuators stand out as a robust and efficient solution for applications requiring high force and precision linear motion. Their ability to deliver significant power in a compact form, maintain consistent force and torque, and function effectively over long distances without significant power loss makes them indispensable in various industrial settings.
However, their efficiency is somewhat tempered by potential fluid leakage, environmental concerns, and the complexity of their supporting components. Despite these drawbacks, the advantages of hydraulic actuators often outweigh the disadvantages, making them a preferred choice for challenging mechanical tasks where reliability and performance are critical.
