HYDRAULIC ACTUATORS

We were discussing hydraulic flow control valves and its various types in our previous post. We have also seen the working principle and applications of pressure compensated flow control valves and non pressure compensated flow control valves in our previous discussion.

Today we will see here the hydraulic actuators with the help of this post, at the end of this post series, we will be able to understand various types of hydraulic actuators in hydraulic units.

Let us first see here, what is hydraulic actuator?

As we know that hydraulic system is used for transmitting and controlling the power, there will be a hydraulic pump which will be driven by electric motor or engine and it will create the flow of fluid. Fluid pressure, direction and flow will be controlled by various hydraulic valves.

Hydraulic actuators convert pressure energy of hydraulic fluid in to mechanical energy. Mechanical energy, produced by hydraulic actuator by converting pressure energy in to mechanical energy, will be in the form of mechanical force or motion.

There are mainly two types of hydraulic actuators as mentioned here

Linear actuator: Linear actuator provides the motion or force in straight line and such hydraulic actuators are termed as hydraulic cylinder.
Rotary actuator: Rotary actuator provides the rotary motion or torque and such hydraulic actuators are termed as hydraulic motor.

Linear actuator or hydraulic cylinder

Hydraulic cylinders provide mechanical force and motion in a straight line. Hydraulic cylinder will have one piston or plunger which will be operated due to the hydraulic pressure of fluid within a cylindrical housing.

There will be two ends of a hydraulic cylinder as displayed in following figure, first one will be termed as rod end head from where cylinder rod will be extended and second end i.e. opposite end will be termed as cap end head and their respective fluid supply connections will be termed as rod end port and cap end port.