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Introduction of the New Unimog Generation | Model Series 405
System components
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The components are arranged sequentially: friction clutch,
transmission. In the transmission, the direction of rotation of
the engine can be inverted via the reversing group by means
of a switchable gear set and the torque can be transferred
via the countershaft to the main transmission. In the process,
power is transmitted by the gears with an efficiency of > 0.9.
In a third position (neutral position), the torque of the engine
can be diverted to a hydraulic pump via a dog clutch. An oil
volume can be steplessly transferred to the hydraulic motor
in both directions via the closed high-pressure circuit.
The hydraulic motor draws in the oil volume from the pump
hydrostatically and transfers the resulting torque to the coun-
tershaft via an additional dog clutch and thus to the main
transmission when a gear is engaged. A variable gear ratio for
rpm and torque is produced by adjusting the volumes in the
pump and motor. As a result of mechanical and volumetric
losses, the resulting efficiency levels are lower, ranging from
0.4 to 0.7.
Through the use of hydraulic assemblies which can be electri-
cally adjusted to zero output, it is possible to interrupt power
transmission to allow engagement/disengagement and shif-
ting of transmission stages while driving. By simultaneously
reducing the volumes of the hydraulic pump and hydraulic
motor on a proportional (ratiometric) basis, it is possible to
interrupt the power transmission of the hydraulic assembly
without changing the gear ratio.
Measuring the high pressure allows the transmission to be
shifted into an unpowered state at the optimal time. Ope-
ning the drive clutch allows the hydraulic assemblies to be
completely shut off while driving by means of dog clutches.
The pressure control system in the high-pressure circuit
allows the hydraulic assemblies to be adjusted for optimal
performance.
– This printout will not be recorded by the update service. Status: 03 / 2013 –
