Rotary Actuator: 5 Prominent Types and Their Application

Rotary actuators serve to convert energy into controlled rotational force and ultimately produce a rotary motion or torque. Boasting amazing versatility – numerous aperture sizes, and just as many table diameters, motor choices, and mounting options – they can be used in various industries.

Those familiar with power control units recognize two types of actuators – linear and rotary.

But there are also more than a few subtypes of rotary actuators, each of them designed differently to provide a wide range of movements and control various types of valves. Based on their shape, size, and design, but also their power source and application, we classify them in five main types:

Helical

Rack-and-Pinion

Manual

Electric

Fluid

Here’s everything you need to know about them and their application.

Helical

Helical rotary actuators use multiple helical gears to produce rotational movement by converting the linear movement of the piston into controlled force. Connonsiers know them to be highly reliable, simple, powerful, and balanced, which is why they boast many fields of application.

Apart from being all this, helical rotary actuators are also less expensive.

Together with rotary position control, a highly effective backlash eliminating mechanism allows for this type of actuators to be smaller and lighter without compromising the accuracy of position. On the contrary, the accuracy of helical rotary actuators is exceptionally high.

Because they are both simple and effective, helical rotary actuators are used for artificial and robotic leg and arm joints, medical devices, military equipment, landing gear, lifting equipment, construction equipment, earthmoving equipment, and subsea valves.

Rack-and-Pinion

Rack-and-pinion rotary actuators, also known as limited rotation cylinders, are the weapon of choice in scenarios that require high torque. They produce restricted rotation by converting force through a diagonally placed (bidirectional) piston or multiple pistons.

Hailed for their versatility, rack-and-pinion rotary actuators are also extremely reliable.

The ability to withhold heavy loads is another differentiating point of these actuators.

As previously mentioned, limited rotation cylinders dominate the high torque industries. You can find them in the tire industry, steel industry, cement factories, and power stations, where they showcase great mechanical efficiency and excellent durability.

Manual

The manual rotary actuator may be the simplest type of power control unit, but it’s certainly not the weakest. It does require manual screw rotation, however, and relies on unpowered, hand-operated gearboxes, knobs, handwheels, or levers to produce the desired torque.

Manual rotary actuators are also referred to as valve operators.

This is because valves are their primary field of application, including nearly every type from butterfly and ball valves to check and globe valves. In this age of automation, manual rotary actuators are used mostly by small organizations and in systems for oil and gas extraction.

Electric

Electrically powered rotary actuators convert energy into rotational motion by using motors and output shaft mechanisms with limited rotary travel. They are designed to provide high-performance, high-accuracy positioning for dampers and valves, as well as great control.

There are a variety of applications for electric rotary actuators.

Depending on the specific design, they can be used for semiconductor manufacturing operations, in the healthcare industry, packaging applications, high-power switching gears, and the electric power industry. You can also find electric rotary actuators in car seats.

State-of-the-art applications of electric rotary actuators include industrial robotics, where this type of actuator allows for unrestricted rotation, accurate programmability, and effortless setup. Needless to say, electric rotary actuators vary in size, design, and price.

Fluid

Fluid-powered rotary actuators convert hydraulic fluid, gas, or differential air pressure into rotational movement by using cylinder and piston mechanisms, as well as gearing and output shafts with limited rotational travel. The movement they produce is highly controlled.

This type of rotary actuator can be found where you least expect it.

Nearly all industries with automation applications use fluid-powered rotary actuators. Door closing and opening, damper closing and opening, and clamping are most commonly cited as the three main fields of applications for fluid-powered actuators, but they are not the only ones.

Rotary actuators of all shapes, sizes, and types are everywhere around, helping industry leaders perform everyday tasks and deliver high-quality results. They are indispensable in engineering and construction, for instance, where they help achieve perfect precision.

Other applications of rotary actuators include industrial robotics, fiber optics, photonics, and medical component laser machining. The steel industry relies on their accuracy too, but they are also useful in military operations, the oil industry, and chemical processing plants.

Due to their amazing versatility, rotary actuators are used across industries and sectors.