Principle And Application of Linear Actuator

1. What is an linear actuator?

Linear actuator, also known as electric linear actuator, is a electromechanical device that converts the rotational motion of a motor into linear reciprocating motion of a push rod. It is an efficient and precise linear drive solution used for pushing, pulling, lifting, lowering, and adjusting various equipment and components.

In simple terms, it's an electrically controlled telescopic rod.

2. Working Principle and Core Components

The working principle can be summarized as: motor → transmission mechanism → linear motion.

Core components include:

Motor: The power source, typically a DC motor (e.g., 12V/24VDC), AC motor, stepper motor, or servo motor.

Transimissiongear ：

Gearbox: reduces the motor's high speed and increases output torque. Commonly uses worm gears or planetary gears.

The screw is the key component that converts the rotary motion into linear motion.

The sliding screw has the advantages of simple structure and low cost, but it has the disadvantages of low efficiency and fast wear.

Ball screw: The ball screw is the first choice of high performance push rod because of the low friction, high efficiency, high precision and long life.

Push rod: a telescopic rod usually driven directly by a screw or nut, with an installation joint at the front end.

Limit switch/Hall sensor: limits the push rod's maximum extension and retraction.

Enclosure: Protects internal components and serves as the mounting base.

Controller: used to control the motor's forward and reverse rotation, stop, and can integrate speed regulation, position feedback and other functions.

3. Main Application Areas

linear actuator is used in almost all industrial and civil fields which need linear motion.

Industrial automation ：

Production line: workstation lifting, valve operation, material feeding, and positioning fixture.

Robot: As a joint actuator, it achieves precise linear motion.

Medical and rehabilitation equipment:

Bed/Operating table: precise adjustment of backrest, leg board, and overall height.

Nursing bed: convenient for patients to sit up and turn over.

Smart home and furniture:

Lift desk: Work in alternating sitting and standing positions.

Electric sofa/bed: Adjust the backrest and leg support.

Kitchen appliances: concealed lift cabinet and adjustable range hood height.

Cars and transport:

Car tailgate/side door: Intelligent electric opening and closing.

Seat adjustment: Electrically adjustable seat height, front/rear, and tilt.

Aerospace ：

The aircraft is used for cabin seat adjustment, dining car locking, small table, cabin door assistance, etc.

New energy and environmental protection:

Solar panels: automatically adjust the panel tilt angle based on the sun's position to maximize power generation efficiency.

Wind turbine: adjusting the pitch or yaw of the blades.

4. Key Parameters for Model Selection

When selecting an linear actuator, consider:

Thrust/Pull: The unit is usually Newton (N) or kilogram-force (kgf).

Stroke: maximum extension length of the push rod.

Speed: usually measured in millimeters per second (mm/s).

Operating voltage: such as 12VDC, 24VDC, 220VAC, etc.

Protection rating: IP54 (dust and water resistant) or IP66 (highly resistant to dust and water), designed for outdoor or harsh environments.

Load cycle: refers to the ratio of working to resting time, which affects heat dissipation and service life.

Location feedback required: e.g., potentiometers or encoders for closed-loop control.

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