Linear Actuator Review

Hydraulic and Pneumatic Knowledge

Linear actuator is a mechanism or assembly that creates motion and force along a straight line utilizing an externally applied energy source The following are the various methods of achieving this linear motion.

Linear Actuator Types:

Mechanical Linear Actuator: These actuators typically convert rotary motion of a General or Stub ACME screw thread or worm gear into linear displacement and force. A classic example is an automotive car jack or scissor type jack. Mechanical linear actuators are also used to position lasers and optical devices, as well as the position of rotary stages, linear stages, and other positioning instrumentation. Some mechanical linear actuators are designed with an optical, digital encoder or an Linear Voltage Displacement Transducer (LVDT) to assist in accurately positioning the linear actuator.

Electro-Mechanical Linear Actuator

Hydraulic Linear Actuator: Also called hydraulic actuator or cylinders are a fluid pressure actuated linear motion piston within a enclosed cylinder. The two isolated sides of the hydraulic piston are either pressurized or de-pressurized to achieve linear movement of the piston to create the linear motion and force. An example of a hydraulic actuator is a hydraulic cylinder utilized on an automotive repiar lift utilized by mechanics to access the underside of a automobile for maintenance. The fluid pressure supplied to the hydraulic actuator is either supplied by a manual fluid pump or electric pump.

Pneumatic Linear Actuator: Also called an air actuator or cylinders are a air pressure actuated linear piston within a enclosed cylinder. Pneumatic actuator are almost identical to hydraulic actuators except that the actuating fluid is air not liquid.

Electro-Mechanical Linear Actuator: These actuators are simply mechanical actuators that are operated by electrical power via a electric motor or similar. Typical applications for an electro-mechanical actuator are the transversing motion applied to a vertical milling machine. The ACME thread is rotated by a electric motor to achieve the linear motion.