An Electric Linear Actuator can be split into its two main sections:

Drive Unit a) Gearbox and motor. Actuation Unit a) Ram section of actuator. The drive unit typically comprises of a gearbox and motor. Although some actuators are direct motor driven with no gearbox. The gearbox is either a single or double stage gear set as standard (helical, bevel, spiroid, worm, or helical-worm type gearing). The actuation unit is based around a lead screw assembly, which converts the rotary motion into linear movement. As the lead screw rotates, the nut extends and retracts the ram, which is attached to the load. The lead screw assembly is packaged inside a ram arrangement with guides and seals to provide a sturdy enclosure.

Three types of lead screws are used in electric linear actuators: Machine Screw, Ball Screw & Roller Screw.