Hydraulic and Pneumatic Knowledge
Fluid Power Equipment | Hydraulic Actuators

Previous Page

The hydraulic supply and return line is connected to the lower chamber and allows hydraulic fluid to flow to and from the lower chamber of the actuator. The stem transmits the motion of the piston to a valve.

Initially, with no hydraulic fluid pressure, the spring force holds the valve in the closed position. As fluid enters the lower chamber, pressure in the chamber increases. This pressure results in a force on the bottom of the piston opposite to the force caused by the spring. When the hydraulic force is greater than the spring force, the piston begins to move upward, the spring compresses, and the valve begins to open. As the hydraulic pressure increases, the valve continues to open. Conversely, as hydraulic oil is drained from the cylinder, the hydraulic force becomes less than the spring force, the piston moves downward, and the valve closes. By regulating amount of oil supplied or drained from the actuator, the valve can be positioned between fully open and fully closed.

The principles of operation of a hydraulic actuator are like those of the pneumatic actuator. Each uses some motive force to overcome spring force to move the valve. Also, hydraulic actuators can be designed to fail-open or fail-closed to provide a fail-safe feature.

Previous Page

© Copyright 2000 - 2012, by Engineers Edge, LLC All rights reserved.
Disclaimer

Home
Engineering Store
Engineering Training PDH
Products & Services
Engineering Forum
Engineering Design Data
Engineering News
Engineering Videos
Engineering Calculators
Engineering Jobs
Industrial News Buzz
Newsletter Register
Feedback
GD&T Training ASME Y14.5-2009
DFM Training
Contribute Article

Copyright Notice