Liebherr presents hydrostatic-mechanical power-split gearbox

At the 2014 VDI Congress „Drivetrain for Vehicles“ in Friedrichshafen at the end of June Liebherr presented a hydrostatic-mechanical power-split gearbox for the first time. The first development version was designed especially for mobile working machines with extremely high demands with respect to dynamics and reversing.

For more than 60 years, Liebherr has been developing, designing and manufacturing gearboxes for construction machines and other sophisticated applications and in addition has been working on the development of hydrostatic-mechanical power-split gearboxes. The basis for this development was the state-of-the-art technology for the drivetrains on such working machines. This is a field where hydrostatic drivetrains, power shift transmission with hydrodynamic converter and lately also hydrostatic-mechanical power-split gearboxes are employed.

In contrast to the power-split gearbox principles already on the market, the Liebherr principle employs three hydrostatic drive units arranged in parallel instead of the usual two. This gives the Liebherr gearbox a number of advantages over existing concepts, for example especially few switching operations which are easier to manage, even in highly dynamic situations.

The gearbox is currently in the testing phase. A broad range of simulation tools and dynamometer tests are employed to record different parameters and to test the different functions.

To produce an optimum drive solution, Liebherr's engineers have from the very beginning been working very closely with specialists from the vehicle manufacturers. This has allowed the specific requirements of applications with a high proportion of reversing to be taken precisely into account. All components within the drivetrain are supplied by Liebherr.

The first international congress “Drivetrain for Vehicles” took place in 1986. Since then it has developed into an important meeting place for the automotive industry. With more than 80 specialist presentations in all, the latest developments in gearbox technology were reported by many different companies.