Are actuators different from motors?

A servomotor is a packaged combination of several components: a motor (usually electric, although fluid power motors may also be used), a gear train to reduce the many rotations of the motor to a higher torque rotation, a position encoder that identifies the position of the output shaft and an inbuilt control system. Our vane style actuators use hydraulic pressure applied to the shaft mounted vane to produce higher torque than pneumatic applications. Just as it is in pneumatic rotary actuator, the vane configuration type of the hydraulic actuator makes use of pressurized fluid to make the rotation of the vane possible, thereby leading to the rotational motion of the central shaft. High torque rotary actuators have the efficiency and capability of transforming hydraulic power/pressure, electric energy, or pneumatic energy into mechanical rotation.

This rotary actuator provides torque to load the system while the drive motor provides the rotational speed and is sized only to overcome the friction in the system, resulting in an energy efficient test stand. 2 Fluid power actuators are of two common forms: those where a linear piston and cylinder mechanism is geared to produce rotation (illustrated), and those where a rotating asymmetrical vane swings through a cylinder of two different radii. Common design configurations for hydraulic rotary actuators include piston type, vane type, or gear type.

The concepts for efficient high – torque rotary actuators will be valuable in numerous electric drive applications, including industrial motors, material handling, and robotics. The Type 3-EF and Type 5-EF Rotary Incremental Actuators are designed based on a recently developed extra fine step angle permanent magnet stepper motor; which in combination with the standard harmonic drive gear reducers produces extra fine output step resolution. Pneumatic and hydraulic rack-and-pinion rotary actuators are available in a variety of styles and sizes, from compact series to larger series for applications requiring up to 31,000 in/lb of torque.

Vane actuators are a good fit for applications requiring extremely high endurance, high rotational speeds, and a need for constant control of movement without the need to maintain the load in a particular position. Now Linak engineers have developed what they say is a simpler, quieter, and economical alternative: The RA40 rotary actuator consists of a 24V dc permanent magnet motor that turns a series of gear stages to produce a working torque output of 184 ft-lbs (350 Nm) via a rotating arm. A comparison of the response characteristics to the change of an inertia load using a 130mm frame size DGII Series hollow rotary actuator and a direct drive motor that produce equivalent torque was performed.

Since direct drive motors can receive a load directly, generate high torque without a gearhead, and utilize the hollow structure for wiring and piping, they are being used in the industrial equipment field as a positioning system. The ESBE ARC/ ARD series of high torque rotary low voltage motorized actuators provide a 90° operating range of rotation. If no gearing is used, it is possible to accurately control torque output, but large torques are not possible unless heavy direct-drive motors and high-powered current amplifiers are used.

Hydraulic and pneumatic motors are not as common as electric motors, but they are useful in specialized applications that have: high torque requirements, limited weight and space, the motor is subject to stalling and holding loads, and the use of electricity is prohibited because of safety concerns. Based on New Scale’s M3 micro-mechatronic design platform , this new M3-R” rotary actuator module features integrated piezoelectric motors, tangential drive mechanism, angular motion sensor, and all drive and control electronics into a compact footprint of less than 1 cubic inch. Resulting from the successful completion of a Phase 1 SBIR project for the US Navy, this non-inductive rotary actuator module delivers higher power output in a smaller footprint than electromagnetic pancake motors or other piezoelectric actuators.

The hydraulic rotary actuator is a device which transform hydraulic power (pressure and flow) in mechanical power: torque and angular speed. Since rotary actuators operate at low speed with high torque, torque output rather than the horsepower is used for the rating and identification purposes. Max-Air Technology Hydraulic Heavy Duty Series (HHD) Scotch Yoke Actuators are available in two distinct configurations: SHD (symmetric) and CHD (canted) heavy duty selectable torque profiles are designed to perform in the most demanding applications based on valve requirement.

Air or fluid powered rotary actuators for heavy duty, high torque applications. Fail-safe actuators are spring-loaded to ensure the return of the shaft to a safe position – they are available with torque outputs to over 5,000 lb-in.  For more information on high torque actuators, be sure to visit