Liebherr LHM 420 - Manual (Page 23)

23
Liebherr Diesel Engine, Type D9508 A7
Drive Concept - Advantages Of Liebherr Hydrostatic Power Transmission
The Liebherr hydrostatic drive is undeniably the most
reliable and high performing drive system for every mo-
bile harbour crane due to rapid achievement of high per-
formance, long-term durability, low maintenance costs
and a series of operation-specific advantages such as
outstanding acceleration and deceleration. This means
higher turnover in shorter periods and proven savings
for the customer.
The crane drive is diesel-hydraulic consisting of a split-
ter gear box feeding variable displacement axial piston
pumps for the hoisting, slewing and the luffing gear. In
an effort to reduce complexity, during travelling pumps
from other operations are used. The splitter gear box
can either be driven by a diesel motor or alternatively by
electric motors.
Closed hydraulic circuits technology for maximum per-
formance and high efficiency is used. The independent,
closed circuits guarantee a highly responsive, smooth
and sensitive operation with a minimum of components,
maximising the operating safety even in continuous op-
eration or high ambient temperatures (-40°C to +50°C).
s¬ )MMEDIATE¬AND¬SHORT¬SYSTEM¬REACTION¬TIMES¬FOR¬RAPID¬
and safe working cycles
s¬ !LL¬CRANE¬MOTIONS¬ARE¬APPLIED¬CONTINUOUSLY ¬PRECISELY¬
and simultaneously with maximum speed and load
s¬ (IGH¬PERFORMANCE¬DENSITY¬REQUIRING¬A¬MINIMUM¬OF¬FUEL¬
and energy
s¬ &ASTER¬ACCELERATION¬AND¬DECELERATION¬TIMES¬DUE¬TO¬LOW¬
masses of inertia – higher turnover
s¬ #LOSED¬ LOOP¬ SYSTEMS¬ FROM¬ ¬K7¬ UPWARDS¬ REQUIRE¬
up to 75 % less hydraulic oil than open loop systems
s¬ $YNAMIC¬ BRAKING¬ IS¬ ACCOMPLISHED¬ BY¬ ATTEMPTING¬ TO¬
reverse the rotation of the pump. The pump and prime
mover constitute the dynamic brake
s¬ 5SE¬ OF¬ REVERSE¬ POWER¬ n¬ THE¬ LOWERING¬ ENERGY¬ IS¬ LED¬
back to the power pack (less fuel consumption)
s¬ #LOSED¬CIRCUITS¬ALLOW¬EASY¬FAULT¬lNDING¬AND¬DIAGNOSIS¬
due to separate circuits for each crane function
s¬ /NLY¬ONE¬DRIVE¬SYSTEM¬SIMPLIlES¬AND¬REDUCES¬SERVICE¬
and maintenance costs