Key Considerations for Selecting a Rotary Actuator
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Key Considerations for Selecting a Rotary Actuator

Jan 21, 2024

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Rotary actuators are motors that convert energy into controlled rotational force, or torque, in order to move a specific system or mechanism. Actuators introduce motion, but they can stop it, as well. There are a number of different rotary actuator designs available, including rack and pinion, piston chain, helical spine, Scotch yoke, bladder, and vane. Offering varying features and benefits, each is best-suited for specific types of applications.

Often used in systems in which cylinder mountings are not a viable option, actuators typically run on hydraulic and pneumatic pressure or are electrically powered. Rotary actuator control systems can be either mechanical or electronically-based designs, with actuation achieved either by software or through human intervention. Electric rotary actuators are used much more frequently than their hydraulic and pneumatic counterparts, as they eliminate the need for complex pressure lines, pumps, and safety systems, thus reducing cost.

What Sets Rotary Actuators Apart

Rotary actuators serve as unique, versatile components with a range of applications. These actuators can mount on the equipment pivot point and do not require large clearance for long-stroke lengths as with linear actuators or cylinders. Nor are they restricted to quarter-turn (90°) pivot arcs. In fact, depending on the specific configuration, rotary actuators can achieve arc lengths of 180°, 360°, and even higher, thereby providing the flexibility to satisfy specific motion profiles dictated by the application.

Motorized rotary actuators also allow for superior stability, even when operating at low speeds. Acceleration and deceleration are smooth, and operations can be programmed with numerous stopping points. And for actuators that use a stepper motor and servo motor, the regulation of position and speed can be performed simply using preset data, simplifying their installation and set-up.

There are two main types of rotary actuators: rack and pinion, and vane. Rack and pinion actuators are ideal for high-speed production situations and for cases in which low wear and long life are critical. Therefore, these models are well-suited for heavy-duty applications. Vane actuators, on the other hand, are used to clamp, transfer, or position light loads in medium-speed situations. Because of these actuators’ small size, they’re typically used in applications with limited space.

Rotary Actuator Applications

A broad range of industries and applications make use of rotary actuators. Therefore, models of all sizes, powers, and operating speeds are available off-the-shelf to meet industry’s diverse requirements. Generally speaking, rotary actuators are used for camming, indexing, clamping, braking, tensioning, positioning, tilting, and safety closure systems.

In material handling scenarios, they are used for switching conveyors, turning and positioning container clamps on lift tracts, tensioning and guiding, operating valves, braking systems, and lifting materials.

For metals processing, rotary coils are often employed for upending coils, turnstiles, walking beams, immersion/agitation mechanisms, rollover devices, tilting electric furnaces, crust breaking, indexing transfer tables, and charging furnaces. These actuators also find use in various marine and robotics systems.

Rotary actuators can be inserted into systems with minimal effort, with nothing more required than for the device to be inserted between two links. And since there’s no need for additional components, joints can provide precise, powerful movement, and links do not require additional clearance in the operational environment. This precision makes rotary models well-suited for a variety of applications, as well as various testing scenarios. And finally, using rotary actuators may reduce production times, allowing for quick, efficient operations.

Choosing a Rotary Actuator

Rotary actuators are incredibly versatile and can be used to meet the needs of a full range of industries and applications. With their compact size and host of other benefits, these devices serve as ideal solutions for systems in which actuation using cylinder mounting is not feasible.

When deciding which kind is best for your specific job, be sure to keep in mind a few key factors that will drive the selection process. These factors include mechanical efficiency, package size, shaft options, maximum rotation, and cost. Partner with a reliable, well-respected manufacturer who will be able to guide you through each step of the selection process.


Image Credit: Stanislav Yemets/

What Sets Rotary Actuators ApartRotary Actuator ApplicationsChoosing a Rotary ActuatorReferences: