What is the Difference Between Linear and Rotary Actuators

Difference Between Linear and Rotary Actuators

One of the clearest distinctions between linear and rotary actuators is the direction of movement. Linear actuators move in a straight line, usually in a back and forth motion. In contrast, rotary actuators move in angular degrees with reference to a mid-point, that is, along a circle.

However, it is worth pointing out herein that in their simplest form, linear actuators are an extension of rotary actuators. These contain an additional motion converter that translates rotational motion to linear motion. As stated above, ball screws, roller screws, belts and pulleys, rack and pinion convert rotary movement into its linear counterparts.

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A few other differences between linear and rotary actuators are outlined below:

• A linear actuator delivers a push-pull motion, while a rotary actuator helps with a rolling motion.

• For linear actuators, the end of arm tooling of the CNC mill slides between two points on a rule-like line. As for rotary actuators, the end of arm tooling goes in circles.

• Linear actuators consist of a motor and a gear axle thread. Rotary actuators contain hollow, cylindrical chambers with stationary barriers and a central shaft.

• The output motion of linear actuators is in line with the output shaft. As for the rotary actuators, the output motion is perpendicular to the shaft. 

• Since obtaining linear motion is one of the commonest design functions, linear actuators have a compact build and design. 

• Rotary actuators follow an angular path, and the distance traveled can be infinite and repeated for continuous spinning action. In contrast, linear actuators only travel a limited distance and come to a standstill.

• The use of motion conversion for linear actuators affects the bandwidth and responsiveness of the setup. This is because some amount of tradeoff takes place during the translation.

• Mounting of linear actuators is easier as one does not have to calculate the rotation angle as in the case of rotary actuators.

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