Efficiency of hydrostatic drives of some selected construction machines: Fid-Bau Portal

Efficiency of hydrostatic drives of some selected construction machines

Hammerle, U. / Krimbacher, N.

LIEBHERR is the only manufacturer worldwide, that consequently makes use of hydrostatic drives on the classic earth moving machinery. These are excavators, wheel loaders and crawler dozers and loaders. Especially in combination with a central electronic controller of the complete machine, advantages in comfort, functionality and efficiency can be achieved. The first part of this presentation gives an overview of the range of LIEBHERR earthmoving equipment. The hydrostatic drives and their performance in practice are highlighted. The second part gives a detailed description of the newly developed LIEBHERR reachstacker. The presented drive concept, powering a reachstacker, offers several advantages. Using two independent hydrostatic drives lines offers the ability to influence the drive torque of both pairs of wheels. Therefore the lateral forces on the steering wheels can be minimised and furthermore a longer lifetime of the tyres can be reached. The handling of the reachstacker is also improved, as the steering commands from the operator are converted much more directly to the movement of the machine. Due to the redundant design of a single wheel drive with a hydrostatic drive this system reaches high reliability; the motivity of the reachstacker is maintained. According to this drive concept the machine is cost effective over its life cycle, has an economic and reliable drive system and is fail-tolerant. There are more possibilities to adjust the reference revolution speed of the combustion engine; the revolution speed can be set in such a way that the fuel consumption of the reachstacker can be reduced significant.