Lubrication; Hydrodynamic Lubrication Of The Axial Tilting Pad Thrust Bearings; Hydrodynamic Lubrication Of The Axial Tilting Pad Thrust Bearings In Gear Units With Hydrostatic Start-Up Assistance - Siemens KMS Assembly And Operating Instructions Manual

5.3

Lubrication

The lubrication and cooling is provided by continuous oil circulation through a separate oil-supply system.
To prevent vibration and to compensate for heat expansion, compensators are provided in the pipe
system.
Note
When operating and servicing the components of the oil supply system, observe the operating
instructions of the components.
For technical data, refer to the data sheet and/or the list of equipment.
For a detailed illustration of the gear unit and oil-supply system, refer to the drawings in the gear unit
documentation.
The kind of lubrication can be found on the order-specific equipment list, the lubrication diagram and the
"Technical Data Sheet" of the gear unit.
Depending on the gear unit version, one of the following three lubrication systems is installed in the gear
unit.
Toothed parts and rolling bearings are force-lubricated and cooled through the low-forced lubrication
circuit.
5.3.1

Hydrodynamic lubrication of the axial tilting pad thrust bearings

In low ambient temperatures, the oil must be pre-warmed. If agreed by contract, immersion heaters will be
installed in the gear unit housing or the oil tank, or a separate heating circuit will be provided (see equipment
list and lubrication diagram).
The oil is drawn in by the oil pump, cleaned in the double-changeover filter, which is fitted with an optical
and electrical contamination indicator, then cooled in the cooler and conducted to the lubricating points.
The oil flow is divided by valves and orifice plates or control valves for the lubrication of the gears and tilting
pad thrust bearing.
Volumetric flow, pressure and temperature are constantly monitored by monitoring equipment. To prevent
vibration and to compensate for heat expansion, compensators are provided in the pipe system.
5.3.2 Hydrodynamic lubrication of the axial tilting pad thrust bearings in gear units with hydrostatic start-up
assistance
In addition to the hydrodynamic lubrication, part of the oil is fed immediately downstream of the cooler to
the high-pressure pump through a branch circuit.
The high-pressure pump is designed as a radial piston pump and supplies a constant oil quantity at each
connection. The oil is conducted to four axial thrust bearing segments distributed around the
circumference. Before the mill is started, the oil is pumped between the pads and the race. A bearing oil
film will form immediately. After 2 minutes in operation at operating speed, the high-pressure pump must
be turned off.
Pressure switches without pressure transmitter this operating phase and the non-return valves built into
the pads prevent the oil from backing up during normal operation.
BA 9137 en 12/2015
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