Instruction Manual

Hydraulic Solutions
for Transportation Applications
Electro-Hydraulic Actuators Special
Dampers
Passive Running
Gear Control
Liebherr’s range of hydraulic systems for rail vehicles and
busses includes simple passive dampers as well as elec-
tro-hydraulic actuators and complete leveling systems.
Electro-hydraulic actuators (EHA) work as compact, high-performance “power houses” in rail vehicles and are
developed and produced by Liebherr to meet specific customer requirements.
Applications
Applications include active lateral suspension and active
lateral centering systems, car positioning systems, active
radial control, active wheelset control and tilt technology.
Among other attributes, EHA make a valuable contribu-
tion to reducing the burden on the environment and to
reducing wear – all while increasing performance. At train
speeds of up to 350 km/h EHA are being used to move
heavy loads of several tons into the position specified by
intelligent control units, or counteract vibrations occurring
on the vehicle. They make faster train speeds possible and
increase passenger comfort.
Wear Reduction
A further key advantage of EHA is that they reduce car
and infrastructure wear enormously. The initial high invest-
ment costs are recouped very quickly through lower main-
tenance expenses, reduced total energy costs and higher
carrying capacity compared with conventional hydrau-
lic systems. EHA are self-contained hydraulic systems.
Liebherr performs their assembly, filling and final testing
under extremely clean conditions and thus ensures that
they will achieve many years of service in the tough envi-
Steering Damper
The steering damper replaces a rigid steering mechanism,
which serves as the cross-connection between the cars at
the steering joint.
It both improves the vehicle’s running behaviour and
reduces the forces in its structure.
Moreover, the device features final position damping, which
reduces high forces and noise in the stroke limit area.
Intercar Damper
On straight tracks, the intercar damper eliminates rela-
tive movement by interlocking tram bodies. In curves and
during travel at low speeds, this interlocking mechanism
is deactivated.
To simplify maintenance and diagnosis, the damper is also
fitted with a monitoring system.
Such monitoring systems can be integrated into all
Liebherr dampers.
Buckling Protection System
The buckling protection system is mostly used on four-
unit or longer low-floor trams. Its hydraulic control
guarantees compliance with clearance values under all
operating conditions. However, if the buckling control
system fails with the result that compliance is no longer
ensured, it connects with a safety-critical system, which is
additionally monitored by Liebherr electronics.
In addition, the system significantly increases passenger
comfort and reduces wheel and tyre wear.
Hydraulic Bogie
Coupling System
This system reduces the lateral forces between rail and
wheels by coupling the swivel angles of the two bogies.
Due to its damping valves, the hydraulic bogie coupling
system also performs the damping function - there is no
need for additional yaw dampers.
In addition, system offers a very simple method of moni-
toring the damping function.
Leveling Control System
The leveling control system adjusts the entrance height of
the car to each station or platform.
It also facilitates the coordination of the vehicle‘s and
reduces the strain on wheels and rails.
Thanks to a backup system, the vehicle can be kept at the
right level even if the main system fails.
Drawing on a wealth of technical expertise comprising
transportation systems, aviation and construction machin-
ery, Liebherr is able to satisfy individual customer require-
ments through innovative products.
ronment of rail transport. The car manufacturers simply fits
the EHA to the vehicles and installs the cable connection
for the energy supply and control systems. The time-con-
suming installation work required on conventional hydrau-
lic systems to route the line, fill and vent the circuit is thus
eliminated. This also removes the risk of contaminating the
hydraulic fluid through incorrect installation work and, as a
result, damaging the actuator. The system could almost be
described as having ‘plug and play’ functionality.
Maintenance-Free
EHA from Liebherr are fundamentally maintenance-free. If
a fault should occur, however, the entire unit can be quickly
replaced without any hydraulic expertise, thus avoiding
prolonged vehicle downtime.
Steering damper ð
Intercar damper ð
Articulated bus damper ð
Buckling angle control system ð
Buckling protection system ð
Hydraulic roll coupling system ð
Hydraulic bogie coupling system ð
Active yaw damper ð
Active lateral suspension and carbody centering ð
Hydraulic roll compensation ð
Hydraulic levelling system ð
Leveling control system Hydraulic power unit
Electro-hydraulic actuator with fully
integrated electronic
Electro-hydraulic actuator concept Buckling protection system Steering DamperIntercar damper