Electro-Hydraulic Steering Unit

July 1, 2015

Ryan Gehm

Concentric AB’s new electro-hydraulic steering (EHS) unit, designed primarily for servo steering applications in trucks, buses, and off-highway applications, offers system power savings through its variable pressure and speed control capability with the option of low-noise pump technology and direct electronic control features via CAN bus communications. It also offers on-demand steering and variable speed capability, down to a low of 350 rpm in typical steering cycle mode. Depending on application, the unit can be rated up to 276 bar (4000 psi), with flow from 12 to 80 L/min (3.2 to 21 gal/min) and peak output from 1.5 to 7 kW. The base components for the EHS unit embody an advanced development of Concentric's current dc electric motor pump technology. The new EHS product range allows CAN bus communication between the motor and the vehicle's main control system so as to control pressure and flow on demand, significantly reducing system losses compared to traditional mechanical drive systems, the company claims. EHS was developed in collaboration with a supplier of electric motors, resulting in a permanent magnet, brushless dc motor with integrated motor drive electronics. The elimination of brush wear contributes to the unit's ability to operate continuously and trouble-free. Optional features include IP69K protection and CAN bus control either J1939 or CAN-open.