For consistent, optimal system pressure and high-precision power support

The 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 40% 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 Varioserv® drive can be realized via a gear or belt, depending on the customer requirement. A pressure level up to 200 bar can be achieved if this is required by the steering design. Varioserv® can also be combined in tandem with other pump types (e.g., fuel pre-feed pump) to enable additional applications. Both pump parts are connected via an intermediate housing and a shaft coupling.

Individual product request
Das moderne Produktdesign der Nkw-Lenkhelfpumpe Varioserv ermöglicht kontinuierlichen Systemdruck und präzise Kraftunterstützung.
The modern product design of the Varioserv commercial vehicle power steering pump enables continuous system pressure and precise power assistance.


Energy-saving variable displacement pump for hydraulic steering systems

The 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 Varioserv® power steering pump consists of a housing with an integrated control valve, cover, front plate, shaft and a rotor set. The rotor set is comprised of the rotor, eleven radially-guided blades as well as an eccentrically-mounted and hydraulically-adjustable cam ring and an outer ring.

Up to a defined control point, the Varioserv® behaves like a conventional power steering pump. As soon as this control point is reached, the geometric delivery volume is reduced by the cam ring adjustment according to the defined volume flow.

The volume flow is regulated depending on the engine speed and the pressure requirement. This lower delivery volume compared to a conventional power steering pump leads to decreased power consumption and thus a lower system temperature.

Technical data

Details about the
Varioserv® power steering pump

Details about the
Varioserv® power steering pump
  • [1] - 
    Suction port
  • [2] - 
    Pressure port
  • [3] - 
  • [4] - 
    Rotor with vanes
  • [5] - 
  • [6] - 
    Cam ring
  • [7] - 
    Outer ring
  • [A] - 
    Concentrical bearing of cam ring for minimum delivery capacity
  • [B] - 
    Eccentrical bearing of cam ring for maximum delivery capacity
Size 7654 7655 7656
Displacement volume (cm³/rev) 22 25 28
Max. rotational speed (rpm) 5,000
Max. pressure (bar) 185
Controlled volumetric flow (dm³/min) 16-25
Suction port 1 1/16“ – 12UN 2B
Thread (suction port) M26 x 1.5
Pressure port 3/4“ – 16UNF 2B
Thread (pressure port) M18 x 1.5
Drive direction of rotation clockwise or counter-clockwise