Liebherr Downloads - Manual (Page 10)

10
Three Questions to...
Electrohydraulic actuator for roll compensation
Dipl. Ing. Richard Schneider,
Vice President of Product En-
gineering Integrity, Bombardier
Transportation GmbH
1. Mr. Schneider, what are the
latest developments in rail
vehicle construction and what
innovations from Bombardier
Transportation can we expect
to see entering the market?
Of course we are constantly work-
ing on a wide range of innovative de-
velopment projects at Bombardier, and
some of these are now going into se-
ries production.
Most of our developments focus
on energy savings and, in turn, reduc-
ing the impact on the environment, as
well as measures designed to improve
Bogey with roll compensation and active radius steering
performance. We are naturally always
bearing in mind that our solutions must
be cost-effective, too.
I would just like to single out the
development of a bogie with roll com-
pensation, called Bombardier* FLEXX*
Tronic WAKO*; it features integrated
active lateral suspension, and is also
optionally upgradeable with active ra-
dial steering (ARS).
Swiss Railways (SBB) has just or-
dered new double-deck trains from
us in order to expand its inter-city rail
services; these are all fitted with this
innovative bogie. The new train sets
increase curve – combined with im-
proved ride comfort – thanks to the in-
novative roll compensation and lateral
suspension. Active radial steering also
demonstrably reduces the wear be-
tween the rail and wheel, thus slashing
this very costly maintenance overhead.
2. How does roll compensa-
tion work specifically and
what exactly are the ad-
vantages of this technol-
ogy?
Roll compensation is the best
solution especially for double-
deck trains for increasing speed
by up to 15 % and thus reducing travel
time by up to 7 %, without any losses
concerning passenger comfort.
As it moves around a bend, a car-
riage has a positive tendency to tilt in-
wards due to the permissible degrees
of freedom on the bogie and the posi-
tion of the turning point in relation to
the centre of mass. In this instance we
talk about a virtual pendulum. Due to
the typically high internal resistance
for a virtual pendulum, this behaviour
is actively supported with electro-
hydraulic actuators from Liebherr Trans-
portation Systems. Passengers feeling
unwell as a result of strong rotational
motion – a phenomenon that occurs of-
ten on ”conventional” tilting trains – is
no longer an issue with this solution.
In addition, the vibrations trans-
ferred from the rail to the bogie and
thus to the carriage body are also
actively controlled electrohydrauli-
cally, resulting in
improved ride
comfort.
intersects in the middle of the curve.
As such, the wheelset can roll freely
through the curve; there is virtually no
wear and the forces acting between the
wheel and the rail are reduced substan-
tially. This not only saves energy but
also massively reduces the load on the
infrastructure.
Noise emissions are also reduced
sharply; they are even eliminated on
certain curves. A sharp reduction in the
vibrations transferred to the carriage
body is a welcome spin-off of ARS and
its ability actively stabilises the running
behaviour of the wheelset.
Thanks to this combination of virtual
pendulum and active control, the clear-
ance can also be utilised more effec-
tively, thus enabling comfortable car-
riage body cross-sections to be built.
The straightforward set-up, coupled
with an innovative redundancy con-
cept, translates into levels of reliability
that are up to 150-times higher than
existing conventional tilting sys-
tems.
Thanks to FLEXX* Tronic
WAKO* the timetable can be
maintained even if compo-
nents fail.
3. Why is wear reduced
so dramatically through
active radial steering?
The wheelsets are aligned in
parallel on a classic bogie and
pulled through the curve of the rail
in this form. This gives rise to high
forces and high wear.
Thanks to active radial steer-
ing, called Bombardier* FLEXX*
Tronic ARS, the wheelsets are
aligned radially, which means that
the projection of the axle centres
4. Why has Bombardier decid-
ed to team up with Liebherr as
the development partner for
its roll compensation system?
It was important for us to find a reli-
able partner with extensive experience
in the field of integrated hydraulic sys-
tems for this innovative project, and one
who could also bring along know-how
from the field of rail vehicle construc-
tion. We know Liebherr-Transportation
Systems from many years of successful
collaboration on projects involving car
air conditioning systems, and hydrau-
lic systems for our bogies. Suppliers
with high standards such as Liebherr
can also help Bombardier Transporta-
tion retain its position as technology
trailblazer and offer customers the best
possible overall concept.
* BOMBARDIER, FLEXX and WAKO
are trademarks of Bombardier Inc. and
its subsidiaries