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Digital hydraulic motor technology

Digital pump mode

Digital motor mode

High Torque Low Speed (HTLS) motors function as they did half a century ago, though continuous refinements has increased pressure capability, lifetime has been prolonged and production has been cost-optimized. Today's motors are some of the most robust machines in the hydraulic industry. The major limitation is on controllability, where very few options are provided, e.g. 2 step displacement.

​With Diinef's Digital Distributor Valve System a disruptive change in performance and functionality is achieved.

With electronic control in the heart of the motor, each cylinder is freely connected to high- or low pressure. We now call it a "digital motor" as cylinders are either enabled or disabled. The result is a range of functions and features that makes the motors attractive as high power, high efficient controlling devices in a range of applications.


Digital motor benefits

  • Power capacity is increased 2-3 times.

  • Full corner power. Motor deliver max torque at max speed

  • Significant loss reduction, typically 50 %

  • Multi step displacement from free-wheeling to full torque, depending on the number of cylinders

  • Dynamic braking with energy regeneration

  • Speed control, speed limitation

  • Torque control, torque limitation

  • Extremely precise creep mode for positioning (less than 0.25° shaft revolution)

  • No-drift hydraulic lock

  • Direction shift (without shifting pressure sides)

  • Overpressure protection on each cylinder

  • Monitoring of pressure, speed, position and temperature from integrated sensors

  • Real time service life estimation based on actual loading


Diinef valves have large poppet elements that secure excellent "breathing". Valve activation is adjusted for optimal timing whatever the motor runs forward or reverse or as pump or motor (4-quadrant optimized). Digital motors can operate in pump mode, sending oil from the low pressure side to the high pressure side​​. Without switching pressure side, the motor can reverse torque in as little as 50 ms.


If all valves are closed, the motor is locked. And since poppet valves are very low leakage, drift is minimal and in most cases zero.

If all cylinders are connected to low pressure the motor is freewheeling.

Displacement is controlled by freewheeling only some cylinders , e.g. if every second cylinder freewheel the result is 50 % displacement. The more motors and motor cylinders that are driving together, the finer grained control is achievable within acceptable limits for ripple.


Diinef has developed a range of control methods, some of which are patented. They make it possible to set up control systems for a wide range of applications.

Fast ethernet communication along with configurable no-power states enable safe and robust system configurations.

Conventional Bauer HML5-1.0

One digital cylinder

Conventional Bauer HMK18-32.6

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