Electric actuator bridges the pneumatic-hydraulic gap

Hoerbiger-Origa has developed an electrically-driven extending rod actuator which resembles a pneumatic or hydraulic cylinder, but delivers better positional accuracies and higher power densities than pneumatics, at a fraction of the cost of a hydraulic system.

Based on a ballscrew, the OSP-E SBR actuator (above) is suitable for both continuous-duty and high-speed operations. The rod which moves out of the main housing is a hollow tube that extends from the ballscrew, and has a maximum stroke of 500mm.

The prime mover can be almost any type of motor - DC, induction, stepper or servo - or, in potentially explosive environments, an air motor. The actuator comes in three bore diameters (25, 32 and 50mmm) and in 5mm or 10mm thread pitches, with the 10mm version producing stroking speeds of up to 1.2m/s at 3,000 rpm. The maximum thrust is 1.68kN and the claimed repeatability is 0.05mm.

"To date, users have really only had a choice between pneumatic and hydraulic," says Ian Jones, Hoerbiger`s UK sales manager, "but a huge percentage of applications fall between the optimum performance bands of the two technologies."

He points out that that, unlike fluid power cylinders, which require support engineering in the form of compressed air systems or hydraulic power packs, electric drives are easy to fit. He expects the new system to be particularly attractive for applications with few axes where it is difficult to justify the expense of a compressor or power pack.

Potential applications include high-speed lane diverters on conveyors, push-pull positioning systems and hinged movements.