ECO through and through: e-Varioserv® power steering pump

The e-Varioserv® power steering pump supplies exactly the right amount of oil that is needed for operating hydraulic steering systems in commercial vehicles.

Lower temperature up to 15° C

requires fewer cooling measures in the steering system and enables improved system efficiency

Up to 65% less fuel consumption and CO2 emissions

compared to conventional power steering pumps


Modular assembly system

Our wide-ranging production program includes various pump designs and model series. We would also be happy to customize our solutions optimally to your individual wishes and requirements. Evamo's highly flexible modular assembly system makes most anything possible.

The e-VarioservV® power steering pump can also be driven by a gear or belt pulley. If required, a pressure level of up to 200 bar is available. The e-Varioserv® can be combined in tandem with other pump types (e.g., fuel pre-feed pump). The connection for this is made via an intermediate housing and a shaft coupling.

Individual product request
The modern product design of the power steering pump and the attached ECO valve ensure energy savings for commercial vehicles.


Full performance with minimal power consumption

The e-Varioserv® power steering pump is designed for connection to the air compressor or a power take-off on the engine. The shaft connects by means of a cross-slotted disk or spline toothing.                                

The e-Varioserv® consists of a housing with an integrated control valve, cover, front plate, shaft, and rotor set as well as an ECO (electronically controlled nozzle). The ECO enables a demand-driven lowering of the volume flow depending on the vehicle-specific requirements.

The rotor set is comprised of a rotor, eleven radially-guided blades as well as an eccentrically-mounted and hydraulically-adjustable cam ring and an outer ring.                                                                             

The e-Varioserv® behaves like a conventional power steering pump up to a defined control point. As soon as this control point is reached, the geometric delivery volume is reduced by the cam ring adjustment. In addition, the volume flow is also reduced by the ECO valve.

The ECO valve is controlled depending on the vehicle-specific requirements. This lower delivery volume compared to a Varioserv® pump leads to a further decrease in power consumption and thus a lower system temperature.

Technical data

Details about the
e-Varioserv® power steering pump

Details about the 
e-Varioserv® power steering pump
  • [1] - 
    Electronically-controlled orifice (ECO)
  • [2] - 
    Suction port
  • [3] - 
    Pressure port
  • [4] - 
    Rotor with vanes
  • [5] - 
  • [6] - 
    Cam ring
  • [7] - 
    Outer ring
  • [8] - 
  • [A]  - 
    Concentrical bearing of cam ring for minimum delivery capacity
  • [B] - 
    Eccentrical bearing of cam ring for maximum delivery capacity
Displacement volume (cm³/rev) 25
Max. rotational speed (rpm) 5,000
Max. pressure (bar) 185
Controlled volumetric flow (dm³/min) 5/25
Suction port 1 1/16“ – 12UN 2B
Thread (pressure port) M26 x 1.5
Pressure port 5/8“ – 18UNF 2B
Thread (pressure port) M16 x 1.5
Drive direction of rotation clockwise or counter-clockwise