Pneumatic Rotary Actuators Information from Micromatic

05/03/2013
Using pressurized air to perform mechanical rotation is what pneumatic rotary actuators are all about. These simple machines are excellent in applications that require a compact design to deliver repetitive motion such as:
  • Load, position, & unloading
  • Continuous rotation
  • Material handling
  • Valve actuation
These are just a few of the many applications pneumatic rotary actuators perform. Aside from function, you have a number of designs to choose from. Vane rotary actuators use an internal stop to limit rotation. Double-vane and triple-vane designs use two or three chambers, respectively, to increase torque at the sacrifice of rotation. Other types of actuators include spline (a screw-type), rack and pinion, and bladder-actuated.

Characteristics to keep in mind when you are looking for a pneumatic actuator are operating pressure, operating temperature, maximum torque, rotation, axial load and radial load capacity.
  • Operating Pressure – This is the amount of pressure your actuators is rated to use. Measured in PSI.
  • Operating Temperature – The faster your actuator needs to function or its work environment is not room temperature – then you need to shield your component or add a lubricant to the air supply. Maybe both. Measure in either Fahrenheit or Celsius.
  • Maximum Torque – This is the force your actuator is designed to output to do its job. Typically measured with inch-lbs.
  • Rotational Arc – The amount of rotation that your actuator is afforded. Double- and triple-vane actuators reduce this characteristic. Measured in degrees (0-360).
  • Axial Load Capacity – This is the amount of load perpendicular to the axel of the rotary suffers when loaded. This should be minimized and in cases where it cannot be eliminated look for bearing options to protect the actuator from premature failure. Measured in lbs.
  • Radial Load Capacity – This is the bending force imposed on the shaft as it rotates. Also called overhung load adjusting the speed of rotation and usage of bearings can address this issue. Measured in lbs.
Careful analysis of your application and knowledge of fluid control systems are vital in selecting the proper actuator regardless if you decide to use pneumatic or hydraulic power. Other factors to remember are things like positional feedback for precise control or a cushioned stop to minimize excessive wear on your actuator. Contact us today for more information on how we can help with your application.