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MOTORINDIA
l
August 2012
137
provement in fuel efficiency for the
next generation of heavy duty trans-
missions.”
The new synchronizers are con-
figured in single and double cone
arrangements, each with the same
external geometry to allow great
flexibility in transmission design.
In all, four different synchro-
nizer specifications are used on
the 14-speed transmission and
three on the 9-speed. The syn-
chronizers have exceptionally
high torque capacity – up to
18000Nm in the first applica-
tions – and use molybdenum-
coated steel cones for high du-
rability with optimum friction.
Future developments include the
potential for carbon coating.
By increasing the speed of a manu-
al shift, Oerlikon Graziano has been
able to reduce the torque interrup-
tion, keeping the engine at optimum
efficiency for longer and reducing
engine transients to save fuel.
Whichever gear is selected, large
differences in rotating speed can
exist across the other synchroniz-
ers. With a conventional design
this leads to significant drag losses
which impair efficiency, but the new
synchronizers greatly reduce this ef-
fect to further improve fuel econo-
my.
The new synchronizers improve
the shift process during three distinct
phases. Prior to synchronization, the
integrated activation system pro-
vides optimized load characteristics
to give improved consistency and
outstanding durability, compared to
a standard design.
The second phase, synchroniza-
tion, has been shortened by the use
of multi-cone technology, best-in-
class friction materials and the op-
timization of geometries and tribo-
logical properties.
The third phase, from synchro-
nization to engagement, has been
improved by incorporating new in-
ternal features allowing smoother
travel of the sliding sleeve, avoiding
blocking problems and providing a
more friendly engagement feel to
the driver.
“Our priority is to develop trans-
mission technologies that allow our
customers to introduce more capable
and competitive vehicles, whether
for cars, trucks or off-road applica-
tions. The new synchronizers will
support the next generation of truck
transmissions with reduced fuel
consumption and improved driver
convenience”, added Serra.
w
component zone
A key feature of the new technology
is the activation system which is inte-
grated into the synchronizer and opti-
mized for smooth engagement. Appli-
cations are usually manual shift with
air assistance, so any shift problems
are immediately obvious to the driver.
The new system ensures a fast, smooth
and reliable shift under all conditions,
making it an attractive alternative to
a powershift system because it pack-
ages into a much smaller space.