How does a Linear Actuator work?

Linear actuators work by moving an object or piece of equipment in a straight line, moving an object extraordinarily accurately and repeatably if required. The first reason for designing a linear actuator right into a system is for the necessity to move a payload in a linear fashion rather 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 related to the linear actuator by a versatile coupling or a belt, enabling the motor to be mounted either axially or perpendicular to the linear actuator. A wide range of motor sizes might be mounted to these actuators depending on requirements.

Linear actuators have incorporated linear bearings that assist the moving payload, as well as rotary bearings that help either the lead screw, ball screw or belt pulleys. This then allows them to operate as ‘stand-alone’ devices, making them straightforward to mount into current machines and eliminating the necessity to design/manufacture very pricey customized parts. To extend 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 style stage. In this case, a shaft or belt is usually used to keep the 2 actuators in sync with every other.

Features of Linear Actuators

Linear Actuators have the next features:

High repeatability

Positioning accuracy

Smooth operation

Long life

Easy upkeep or maintenance 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 utilized in numerous applications that require a load to either be lifted, lowered, pushed, pulled, rotated or positioned. Linear Actuators are utilized in industries including:

Packaging

Food processing

Industrial vehicles

Factory automation

Materials dealing with

Clean energy

Printing

Automotive

Machine device

Marine

Aerospace

Defence

Pharmaceutical

Types of Linear Actuators

Picking the correct type of linear actuator on your motion application can assist you achieve the most effective results. Lead Screw Actuators, Ball Screw Actuators and Belt Actuators are three types of linear actuators that can be utilized in various 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 methods to provide the rotary motion, as they are generally utilized in low cost 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 might be an advantage as it helps to keep the payload stationary whilst not in motion. Applications embrace agricultural equipment and manual lift systems, where safety and reliability are more critical than precision and performance.

A Ball Screw Actuator uses a high precision nut with recirculating ball bearings that rotate around a ground screw thread. In principle this is very similar to a typical 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 really efficient technique of changing rotary motion to linear motion. Stepper or servo motors are generally used to supply the rotary motion. Ball screw actuators are well suited to repeatable indexing and fast cyclic applications reminiscent of machine tools, scientific devices and medical systems.

Belt actuators work where 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 pushed by a motor which is generally mounted perpendicular to the actuator and paired using a flexible coupling. They offer a comparatively low-cost different, as they inherently have a lower level of precision. Belt pushed linear actuators are excellent for long travel and high linear speed applications similar to packaging and automated material handling systems.