Machinery's Handbook, 31st Edition
Lubricating Films
2501
Hydrodynamic HDL
Boundary BL
Mixed MF
3 x 4 x
2 x
1 x
0.4 0.6 0.8 1.0 2.0 3.0 4.0 5.0 6.0 7.0 10
Lambda λ (Working Film Thickness) Fig. 3. The Relationship between Film Thickness Ratio Lambda λ and Bearing Life
To achieve long life while supporting heavy loads, a plain bearing must successfully manage the relationship between load, speed, and lubricant viscosity. If the load and speed change, the lubricant viscosity must be able to compensate for the change. This relationship is shown in the Stribeck or ZNP curve illustrated in Fig. 4. Choosing the correct lubricant viscosity allows the bearing to run in the favored hydrodynamic range producing a low coefficient of friction ranging from 0.002 to 0.005.
Hydrodynamic HDL
Boundary BL
Mixed MF
Z N P Fig. 4. Stribeck (ZNP) Curve
Copyright 2020, Industrial Press, Inc.
ebooks.industrialpress.com
Made with FlippingBook - Share PDF online