How does a linear actuator work?

A linear actuator is a device that creates motion in a straight line, as opposed to the circular motion of a conventional electric motor. It's commonly used in machinery and equipment to push, pull, lift, or position loads. Here’s a breakdown of how it works, depending on the type:

1. Electric Linear Actuator

The most common type uses an electric motor to produce linear motion.

Working Principle:

1. An electric motor (usually DC or AC) turns a rotating screw.

2. The screw is threaded into a nut that cannot rotate but can move linearly.

3. As the screw rotates, the nut moves along the thread, converting rotary motion into linear motion.

4. A rod or shaft is connected to the nut, extending or retracting as the nut moves.

Key components:

• Electric motor

• Lead screw or ball screw

• Nut (often called a drive nut or actuator nut)

• Guide rails and housing

• Limit switches or sensors (to stop movement at desired positions)

Applications: Adjustable beds, solar trackers, factory automation, robotics.

2. Hydraulic Linear Actuator

Uses pressurized hydraulic fluid (oil) to produce motion.

Working Principle:

1. Fluid is pumped into a cylinder containing a piston.

2. The pressure of the fluid forces the piston to move linearly.

3. Reversing the fluid flow causes the piston to move in the opposite direction.

Applications: Construction equipment (e.g., excavators), industrial presses.

3. Pneumatic Linear Actuator

Similar to the hydraulic version but uses compressed air instead of oil.

Working Principle:

1. Compressed air enters a chamber and pushes a piston.

2. The piston slides along a cylinder, creating linear motion.

3. Air is released or redirected to retract the piston.

Applications: Factory automation, packaging machinery, robotics.

Summary Table

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