Page 67 - Tribology in Machine Design

54 Tribology in machine design

Figure 2.22

moment M. Resolving p and q parallel and perpendicular to P respectively,
the equations of equilibrium become

and

These equations are similar to those used in determining the frictional
moment of the curved brake shoe to be discussed later. The evaluation of
the integrals in any particular case depends upon the variation of p and q
with respect to 0.

2.13.8. Loaded high-speed journal
In a film of uniform thickness and in simple shear, the pressure gradient is
zero. When the journal is placed eccentrically, the wedge-like character of
the film introduces a pressure gradient, and the flow across any section then
depends upon pressure changes in the direction of flow in addition to the
simple shearing action. Let
c = the clearance between bearing and journal,
r + c = the radius of the bearing,
e = the eccentricity when under load,
c — e = ihe film thickness at the point of nearest approach,
c + e = the maximum film thickness,
A = the film thickness at a section X-X.