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 into a system is for the need to move a payload in a linear fashion rather than a rotary one. As most standard electric motors are rotary, a linear actuator is used to convert rotary motion to linear motion.
The electrical motor is generally linked 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 may be mounted to those actuators relying 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 need to design/manufacture very pricey custom parts. To extend the load capacity and stability of a linear actuator system, they can be paired up with the payload carried between them, similar to in an XY gantry type stage. In this case, a shaft or belt is usually used to keep the two actuators in sync with each other.
Options of Linear Actuators
Linear Actuators have the following options:
Easy maintenance or upkeep free
Protection ratings available for some models
Suitable for harsh environments
Rugged and reliable
Industries and applications for Linear Actuators
Linear Actuators can be utilized in various applications that require a load to either be lifted, lowered, pushed, pulled, rotated or positioned. Linear Actuators are used in industries including:
Types of Linear Actuators
Picking the proper type of linear actuator on your motion application will help you achieve the best results. Lead Screw Actuators, Ball Screw Actuators and Belt Actuators are three types of linear actuators that can be utilized in varied applications to produce motion.
A Lead Screw Actuator uses a plain screw/nut arrangement to translate the rotary motion from a motor to linear motion. A manually pushed screw or an AC induction motor are essentially the most commonly used methods to supply the rotary motion, as they’re generally used in low price and low precision applications. The ability of the actuator to ‘back drive’ is reduced over ball screw actuators as a result of low efficiency 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 manual 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 around a ground screw thread. In precept this is very similar to a regular 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 environment friendly method 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 such as machine instruments, scientific devices and medical systems.
Belt actuators work the place a belt is carried between 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 coupled utilizing a versatile coupling. They provide a relatively low-value different, as they inherently have a lower degree of precision. Belt driven linear actuators are excellent for lengthy journey and high linear velocity applications comparable to packaging and automatic material handling systems.