ABSTRACT
W Lubricant flow rate through bearing cm3=mm (gal=min.) Z Number of rolling elements
g Shear rate sec1
da Bearing axial deflection mm (in.) d Contact deformation mm (in.) z 2f=(2fþ1) z Roller tilting angle 8, rad h Lubricant viscosity cp (lb sec=in.2) m Coefficient of friction for boundary or
solid-film lubrication
n1, n2 Poisson’s ratio for bodies 1 and 2 r Radius mm (in.) j Lubricant effective density g=mm3 (lb=in.3) j1 Lubricant density g=mm
3 (lb=in.3) j Roller skewing angle 8, rad s Normal contact stress or pressure MPa (psi) s0 Maximum normal contact stress or pressure MPa (psi) t Shear stress MPa (psi) v Rotational speed rad=sec V Ring rotational speed rad=sec
Subscripts
CG Cage
CL Cage land
CP Cage pocket
CR Cage rail
g Gyroscopic motion
i Inner raceway
j Rolling element location
n Outer or inner raceway or ring, o or i
m Cage or orbital motion
o Outer raceway
R Roller
x0 x0 Direction y0 y0 Direction z0 z0 Direction l Lamina
In Chapter 5, the sources and magnitudes of friction in ball-raceway and roller-raceway
contacts were defined. While these are the salient considerations in the study of effects
of friction on rolling bearing performance, other sources of friction in the bearing can have
significant and even overriding effects on bearing performance. For example, the type of oil
lubrication and the amount of lubricant in the bearing, and the interaction of the cage with
the rolling elements and with piloting surfaces on the bearing rings are important sources of
friction. Also, the interaction of integral contact seals with bearing rings will generally
have a friction effect substantially greater than all of the other sources heretofore indicated.
Seal friction, however, is not a topic explored in detail in this text.
