36
Introduction of the New Unimog Generation | Model Series 405
Design
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Hydraulic pump
A variable displacement and switchable swash plate axial
piston pump of 55 cm³ is used. The rotation direction of the
pump drive is clockwise. It is mounted via an SAE-C mounting
flange with an ANSI B92.1 drive shaft with 21 teeth. The low-
pressure circuit is supplied with 24 bar by an integrated feed
pump. The pump displacement is varied in a pressure range
of 4 -16 bar from 0 cm³ to 55 cm³. The actuating pressure is
controlled on a linear basis with a 24 V proportioning valve
for each direction, ranging from 225 mA - 4 bar to 600 mA
- 16 bar. The pump does not feature an internal mechanical
pressure cutoff function.
High-pressure circuit pressure sensors
Pressure sensors are used at both measuring connections of
the hydraulic pump (forward and reverse high-pressure cir-
cuit). Measuring range 0-600 bar, connection stud M14x1.5
DIN 3852 with sealing ring. Power supply 5 V, ratiometric
voltage output 10% - 0 bar - 0.5 V, 90% - 600 bar
- 4.5 V.
Hydraulic motor
A variable displacement swash plate axial piston pump of 75
cm³ is used. It is mounted via an SAE-C mounting flange with
an ANSI B92.1 drive shaft with 21 teeth. The low-pressure
circuit is supplied by the integrated feed pump of the hydro-
stat pump. The motor displacement is varied in a pressure
range of 4 - 16 bar from 0 cm³ to 75 cm³. The actuating
pressure is controlled on a linear basis with a 24 V proportio-
ning valve, ranging from 225 mA - 4 bar to 600 mA - 16 bar.
When deenergized, the major assembly swivels to the zero
position. No delayed adjustment nozzles are installed in the
low-pressure circuit to improve controllability.
Dog clutches and reversing group
The dog clutches for the new hydrostatic drive are operated
pneumatically by a separate 3/2-way valve actuated by the
ICM. The reversing group is actuated pneumatically by the
transmission control system (TCM) via 3 separate 3/2-way
valves. This allows the reversing group and hydraulic as-
semblies to be switched independently, which allows rapid
switching between the manual transmission and hydrostatic
transmission. The condition of each dog clutch is read in se-
parately by the ICM via separate cam switches.
Cooling
A temperature sensor which senses the oil temperature of
the hydrostatic drive is connected to the STCU. As of 70 °C,
a fan is activated via a relay connected to the STCU and is
shut off again at 60 °C. If the temperature exceeds 80 °C,
a warning is output on the Instrument. If the temperature
does not drop, the adjustable maximum pressure is gradually
limited to reduce the power output capability of the major
assembly.
– This printout will not be recorded by the update service. Status: 03 / 2013 –
