Page 200 - Improving Machinery Reliability
P. 200
Machinery Reliability Audits arid Reviews 171
io,ooo 12,000 14.000 16,000 ia,aoo 20,000
Axial Force +
Figure 3-63. Tapered roller bearing life at various speeds plotted against axial force in a
centrifugal pump.
50,000
40,000
p 30,000
0
3
E.
E 20,000
_I
10,000
-
r -
r
6.000 8,000 10.000 12,000 14,000
Figure 3-64. Ball bearing of comparable size. Life at various speeds plotted against
axial force in a centrifugal pump. (Courtesy Sulzer-Weise, Bruchsal, West Germany.)
How Much Oil Is Enough?
The MRC Bearing Division of SKF USA calculates the theoretical oil flow
required for cooling from the expression:
Q= .000673 x Fr x P x PD x rpm Ib / minute
H, x (To -Ti)
where Fr = coefficient of friction referred to PD
.00076 = cylindrical roller bearings
.00089 = pure thrust ball bearings
,00103 = radial ball bearings
.00152 = angular contact ball bearings
,002-005 = tapered roller bearings
