Waukesha Bearings Horizontal Type Self Equalizing Tilting Pad Thrust Bearings with Forced Lubrication - Manual (Page 3)

The thrust pads are assemblies of a sector shaped steel backing, a tin base babbitt facing and a
hardened steel support disc. For some applications the steel backing is replaced by a high strength
copper material. And some applications use pads in which the backing and the facing are replaced by
bearing aluminum.
The support discs incorporate a spherical surface at the point of contact with its supporting piece,
commonly the upper link. This spherical surface, bearing on a flat surface, provides the freedom for
the pad to tilt and form the carrying hydrodynamic oil film wedge between the pad and the thrust
collar.
The thrust pads are positioned by the base ring and are retained radially either by the bore of the
bearing housing into which the complete bearing is assembled; or, in some designs, by the base ring
itself. In the former arrangement, pad clips are sometimes used simply to retain the pads during
handling and installation of the bearing assembly.
The leveling links are positioned within the base ring as shown in the above drawing and are retained
either by screws or dowel.
The base ring is commonly split to permit the assembly of the bearing radially around a shaft. Where
assembly can be made axially over the end of the shaft, a solid base ring may be used.
Each base ring is provided with an anti-rotation device, commonly a key secured in a keyway on the
OD (outside diameter) of the base ring. Alternately, this may be a dowel pin either on the OD or back
face of the base ring. Whatever is used, it must be accommodated by a corresponding cavity in the
bearing housing.
Lubricating and cooling oil of the proper viscosity, inlet temperature and flow rate is to be supplied to
the annular groove at the OD of the base ring, axially opposite the thrust pads. From here the oil
flows radially inward through slots or holes in the base ring, then axially towards the collar either
through holes in the base ring or through clearance space between the base ring and the shaft. At the
collar this oil flows circumferentially with the rotation and radially outward between the thrust pads
where it is available for generation of the hydrodynamic oil film between each pad and the collar. At
the collar OD the oil is discharged into the surrounding housing.
This surrounding housing normally uses a top oil discharge to insure that the bearing is flooded at
startup. For high speed bearings this top discharge is commonly tangential to aid in efficient removal
of the oil once it has passed through the bearing. For low speed bearings a radial discharge is
satisfactory.
III. INSTALLATION
These bearings are processed with a rust inhibitor and preservative prior to shipment from the factory.
The thrust pads are dip coated with a protective plastic compound which protects against both
mechanical and corrosive damage. These protective coatings 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.