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 first reason for designing a linear actuator right into a system is for the necessity to move a payload in a linear fashion quite than a rotary one. As most conventional electric motors are rotary, a linear actuator is used to transform 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. Quite a lot of motor sizes might be mounted to these actuators relying on requirements.
Linear actuators have incorporated linear bearings that help the moving payload, as well as rotary bearings that support either the lead screw, ball screw or belt pulleys. This then permits them to operate as ‘stand-alone’ units, making them easy to mount into present machines and eliminating the need to design/manufacture very costly custom parts. To increase the load capacity and stability of a linear actuator system, they are often paired up with the payload carried between them, such as in an XY gantry style 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:
Easy upkeep or upkeep free
Protection rankings available for some models
Suitable for harsh environments
Rugged and reliable
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 together with:
Types of Linear Actuators
Picking the right type of linear actuator in your motion application may help you achieve the very best results. Lead Screw Actuators, Ball Screw Actuators and Belt Actuators are three types of linear actuators that can be used 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 pushed screw or an AC induction motor are essentially the most commonly used methods to produce 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 due to the low efficiency of the screw/nut. In some applications, this could 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 round a ground screw thread. In principle 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 changing 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 quick cyclic applications corresponding to machine tools, scientific instruments 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 alongside the actuator. One of the pulleys is pushed by a motor which is generally mounted perpendicular to the actuator and matched using a flexible coupling. They provide a comparatively low-value alternative, as they inherently have a lower level of precision. Belt driven linear actuators are excellent for long travel and high linear speed applications such as packaging and automated material dealing with systems.