Machinery's Handbook, 31st Edition
Bearing Lubricants
2403
320 310 300 290 280 270 260 250 240 230 220 210 200 190 180 170 160 150 140 130 120
Absolute Viscosity, Centipoises, Z 0 2 4 6 8 10121416182022242628
Fig. 6. Viscosity versus Temperature—SAE Oils. Greases: Where full-film lubrication is not possible or is impractical for slow-speed fairly high-load applications, greases are widely used as bearing lubricants. Although full-film lubrication with grease is possible, it is not normally considered since an elaborate pumping system is required to continuously supply a prescribed amount of grease to the bearing. Bearings supplied with grease are usually lubricated periodically. Grease lubrication, therefore, implies that the bearing will operate under conditions of complete boundary lubrication and should be designed accordingly. Lubricating greases are essentially a combination of a mineral lubricating oil and a thickening agent, which is usually a metallic soap. When suitably mixed, they make excellent bearing lubricants. There are many different types of greases which, in general, may be classified according to the soap base used. Information on commonly used greases is shown in Table 1.
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