Waukesha Bearings Tilting Pad Journal Bearings with Forced Lubrication - Manual (Page 3)

Preload in a tilting pad journal bearing is normally defined as follows:
preload m
C
C
b
p
  
1
The preload used for a particular bearing will depend on the application. Preload values are generally
between 0.0 and 0.5, with values of 0.2 to 0.3 common. Negative values are undesirable. Design
clearance values are given on the bearing assembly drawing.
The journal pads are retained loosely in the bearing shell by pins or dowels which prevent
circumferential movement. The bearing end plates position the pads axially.
Split housings and end plates are used where radial assembly of the bearing to the shaft is required.
Where axial assembly is permitted, solid shells (and end plates) may be used and this is common with
the flanged housing types. These use cap screws through the flange and into the bearing housing to
maintain axial and circumferential position. An anti-rotation pin, to locate in a corresponding hole or
slot in the bearing housing, is used on the non-flange types.
Lubricating and cooling oil of the proper viscosity, inlet temperature and pressure is to be supplied to
the annular groove in the OD (outside diameter) of the bearing shell. From here the oil flows radially
inward through the oil feed holes (located between the journal pads) and fills the pad cavity where is
used for lubrication and heat removal. The oil then flows axially along the shaft through the
clearance at the bore of the end plate seals.
If a thrust face is used, the oil discharge from that end of the pad cavity is used to lubricate the thrust
bearing.
The radial oil feed holes in the bearing shell and the end plate seal bore clearances are sized for the
particular application to establish the proper oil flow through the bearing.
III. INSTALLATION
These bearings are processed with a rust inhibitor and preservative prior to shipment from the factory.
This protection should not be removed until installation. At that time, the bearing should be
disassembled and all parts thoroughly cleaned with a lint-free cloth and a solvent such as acetone or
mineral spirits. The bearing is then reassembled (in halves, if a split bearing). Oil all parts at
reassembly to protect against corrosion. The journal pads are all interchangeable as to circumferential
position except as may be dictated by instrumentation, such as pad mounted thermocouples.