SEMA eNews Vol. 10, No. 28, July 12, 2007


Hydraulic components are found many places in the automotive and specialty-equipment industries. They can be found on carbon-fiber hoods and the lift gates of SUVs. They are often slow and noisy. But some people have developed a product that could potentially replace standard hydraulics—the electromagnetic actuator.

According to, the electromagnetic actuator is a highly sensitive motion-control device that employs more reliable and cleaner electromagnetic technologies to replace slower, less precise, larger, noisier and environmentally unfriendly hydraulic components. It’s expected to have hundreds of applications, not only as a replacement technology, but also as an enabling technology. It makes use of an armature in the form of a piston. The piston moves on its own slide bearing rings, which are fitted into pole pieces at each end and at strategic positions along the length of the armature. One of the great things about the technology is that nothing wears but the two bearings and one seal. The piston itself is fitted with an output shaft, rod or thrust tube. The opposite end of the machine can be mounted on a universal joint so as to provide swing in any direction.

The actuator has the ability to operate under water, in a vacuum or in a hostile or sterile environment.  There is zero time delay between current flow and output thrust. The motor is very robust and tolerant of its environment due to the relaxed tolerances of the overall design. The gas spring motor is actually part of the motor. And the actuators themselves have a constant-reluctance design, providing a smooth output force. The actuators are compatible with new and patented forms of automotive uses, and the design may be scaled easily across a wide range of thrusts, velocities and piston travel distances. The article claims that the actuators are totally silent and are environmentally safe. They are precise to five microns, and there is no electromagnetic interference. 

Other features include the fact that the electric piston can be sealed to the stationary structure, allowing it to act as a fluid power element. This is ideal for a gas spring system. The gas spring can therefore be used as a means to support the deadload. The gas spring can also act as an energy storage reservoir in reciprocating mechanisms. And, as the article states, both of the (patented) techniques greatly reduce the power that has to be supplied to the actuator for gravitational or inertial acceleration of the load.

For the entire article, refer to The electromagnetic actuator is a simple yet sophisticated component, which many in the specialty-equipment market will find useful and will have a lot of fun incorporating into the design process.

Source:  “Electromagnetic Actuator.” Retrieved July 6, 2007, from