Linear actuators work by moving an object or piece of equipment in a straight line, moving an object extremely accurately and repeatably if required. The primary reason for designing a linear actuator into a system is for the necessity to move a payload in a linear fashion slightly than a rotary one. As most typical electric motors are rotary, a linear actuator is used to convert rotary motion to linear motion.

The electric motor is generally connected to the linear actuator by a flexible coupling or a belt, enabling the motor to be mounted either axially or perpendicular to the linear actuator. A variety of motor sizes will be mounted to those actuators depending on requirements.

Linear actuators have incorporated linear bearings that support the moving payload, as well as rotary bearings that assist either the lead screw, ball screw or belt pulleys. This then permits them to operate as ‘stand-alone’ gadgets, making them simple to mount into current machines and eliminating the need to design/manufacture very expensive custom parts. To increase the load capacity and stability of a linear actuator system, they can be paired up with the payload carried between them, akin to in an XY gantry fashion stage. In this case, a shaft or belt is commonly used to keep the two actuators in sync with each other.

Features of Linear Actuators

Linear Actuators have the following features:

High repeatability

Positioning accuracy

Easy operation

Lengthy life

Easy maintenance or upkeep free

Protection scores available for some models

Suitable for harsh environments

Compact design

Rugged and reliable

Safe operation

Versatile

Industries and applications for Linear Actuators

Linear Actuators can be used in varied applications that require a load to either be lifted, lowered, pushed, pulled, rotated or positioned. Linear Actuators are used in industries together with:

Packaging

Food processing

Industrial vehicles

Factory automation

Material handling

Clean energy

Printing

Automotive

Machine tool

Marine

Aerospace

Defence

Pharmaceutical

Types of Linear Actuators

Picking the proper type of linear actuator in your motion application may also help you achieve the best results. Lead Screw Actuators, Ball Screw Actuators and Belt Actuators are three types of linear actuators that can be used in numerous applications to produce motion.

A Lead Screw Actuator makes use of a plain screw/nut arrangement to translate the rotary motion from a motor to linear motion. A manually driven screw or an AC induction motor are probably the most commonly used strategies to provide the rotary motion, as they’re generally used in low value and low precision applications. The ability of the actuator to ‘back drive’ is reduced over ball screw actuators as a result of low effectivity of the screw/nut. In some applications, this may be an advantage as it helps to keep the payload stationary whilst not in motion. Applications include agricultural equipment and guide lift systems, where safety and reliability are more critical than precision and performance.

A Ball Screw Actuator makes use of a high precision nut with recirculating ball bearings that rotate round a ground screw thread. In principle this is very similar to an ordinary ball race with the load being transmitted by the rolling balls. The significant advantages of this system are high-precision and low friction, giving a very efficient methodology of converting rotary motion to linear motion. Stepper or servo motors are generally used to provide the rotary motion. Ball screw actuators are well suited to repeatable indexing and fast cyclic applications resembling machine tools, scientific devices and medical systems.

Belt actuators work the place a belt is carried between two pulleys and attached to the moving carriage, then as the belt rotates the carriage is pulled along the actuator. One of many pulleys is driven by a motor which is generally mounted perpendicular to the actuator and matched using a flexible coupling. They offer a comparatively low-value various, as they inherently have a lower stage of precision. Belt driven linear actuators are superb for long journey and high linear velocity applications comparable to packaging and automatic material handling systems.