Page 10 - Tribology in Machine Design

Contents ix

6.3. Traction in the contact zone 233
6.4. Hysteresis losses 234
6.5. Rolling friction 235
6.6. Lubrication of cylinders 238
6.7. Analysis of line contact lubrication 242
6.8. Heating at the inlet to the contact 244
6.9. Analysis of point contact lubrication 245
6.10. Cam-follower system 246
References 247
7. Rolling-contact bearings 248
7.1. Introduction 248
7.2. Analysis of friction in rolling-contact bearings 248
7.2.1. Friction torque due to differential sliding 249
7.2.2. Friction torque due to gyroscopic spin 250
7.2.3. Friction torque due to elastic hysteresis 251
7.2.4. Friction torque due to geometric errors 252
7.2.5. Friction torque due to the effect of the raceway 252
7.2.6. Friction torque due to shearing of the lubricant 252
7.2.7. Friction torque caused by the working medium 253
7.2.8. Friction torque caused by temperature increase 254
7.3. Deformations in rolling-contact bearings 254
7.4. Kinematics of rolling-contact bearings 256
7.4.1. Normal speeds 256
7.4.2. High speeds 258
7.5. Lubrication of rolling-contact bearings 259
7.5.1. Function of a lubricant 259
7.5.2. Solid film lubrication 260
7.5.3. Grease lubrication 261
7.5.4. Jet lubrication 262
7.5.5. Lubrication utilizing under-race passages 263
7.5.6. Mist lubrication 264
7.5.7. Surface failure modes related to lubrication 265
7.5.8. Lubrication effects on fatigue life 265
7.5.9. Lubricant contamination and filtration 266
7.5.10. Elastohydrodynamic lubrication in design practice 266
7.6. Acoustic emission in rolling-contact bearings 268
7.6.1. Inherent source of noise 268
7.6.2. Distributed defects on rolling surfaces 269
7.6.3. Surface geometry and roughness 269
7.6.4. External influences on noise generation 270
7.6.5. Noise reduction and vibration control methods 271
References 272
8. Lubrication and efficiency of involute gears 273
8.1. Introduction 273
8.2. Generalities of gear tribodesign 273
8.3. Lubrication regimes 275