Page 97 - The Tribology Handbook

A17 Tilting pad thrust bearings

The tilting pad bearing is able to accommodate a large
range of speed, load and viscosity conditions because the
pads are pivotally supported and able to assume a small
angle relative to the moving collar surface. This enables
a full hydrodynamic fluid film to be maintained between
the surfaces of pad and collar. The general proportions
and the method of operation of a typical bearing are
shown in Fig. 17.1. The pads are shown centrally pivoted,
and this type is suitable for rotation in either direction.
Each pad must receive an adequate supply of oil at its
entry edge to provide a continuous film and this is usually
achieved by immersing the bearing in a flooded chamber.
The oil is supplied at a pressure of 0.35 to 1.5 bar
(5-221bf/inz) and the outlet is restricted to control the
flow. Sealing rings are fitted at the shaft entry to maintain
the chamber full of oil. A plain journal bearing may act
also as a seal. The most commonly used arrangements
are shown in Fig. 17.2.
Fig. 17.2. Typical mounting and lubrication arrange- SECTION Y-Y
ments Fig. 17.1. Tilting pad thrust bearing

SINGLE THRUST
I OUT

OUT

I
TWIN COLLAR COMBINED THRUST AND JOURNAL
MAIN THRUST

TO SUIT
MACHINE
ARRANGEMENT. LOW .
HIGH OR SPEEO
LOW SPEED

MAY BE SINGLE THRUST (AS SHOWN) OR