Machine Design

Electrohydraulic Actuator Combines dc Motor, Reversing Gear or Gerotor Pump, Relief Valves, and Reservoir, Along with a Double-A

Edited by Stephen J. Mraz

The compact electric hydraulic actuator (EHA) from Parker Hannifin’s Oildyne Div., New Hope, Minn. (, combines all the traditional components of an electrohydraulic linear actuator in a single unit encased in a cast monoblock housing. This reduces potential leak points, simplifies supplier management, shortens installation time, and boosts power density. For example, the unit includes a dc motor, reversing gear or gerotor pump, relief and check valves, reservoir, and double-acting hydraulic cylinder. All components are packaged in a one-piece IP67-rated anodized housing which is delivered flushed, filled, and sealed for “plug-n-play” installation.

Equipped with a fixedclearance gear pump, the device generates 5,000 lbf with noise below 60 dBA. With a gerotor, it delivers 1,600 lbf and noise is under 50 dBA. There are three standard bore sizes (1, 1.25 and 1.5 in.), strokes of 4, 6, or 8 in., and speeds to 4 ips. But the unit can be outfitted with various-sized cylinders and circuits to provide a range of speeds and output forces.

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