his book is one of the excellent textbooks for colleges and universities of Jiangsu Province in 2018, which is based on the demand for mechanical engineering field in teaching reform. It is designed to be used as the basic course for the undergraduate students in mechanical design.
There are fifteen chapters in this book .Its coverage includes introduction；strength of mechanical parts；friction, wear and lubrication；threaded joints；axle and hub connections；rivetings,weldings and bondings；power screws；belt drives；chain drives；gear drives；worm gear transmission；shafts；sliding bearings；rolling-element bearings；couplings, clutches and brakes. Homework problems and projects involving design and analysis provide a basis for the course to follow. At the end, the text is supplemented by a glossary of terms.
This book can be used as textbooks for the course of machine elements in mechanical design or a reference for students, teachers and engineers specializing in mechanical engineering.
Chapter 1 Introduction 1
1.1 The Objectives and Tasks of the Course 1
1.2 Basic Requirements and Design Procedures 2
1.2.1 Basic requirements 2
1.2.2 Procedures for mechanical design 4
1.3 Failure Modes and Design Criteria 6
1.3.1 Failure modes of mechanical parts 6
1.3.2 Criteria for mechanical parts 6
1.4 Common Materials and Their Selection Principle of Mechanical Parts 8
1.4.1 Common materials of mechanical parts 9
1.4.2 Materials selection principle 11
1.5 Modern Mechanical Design Theories and Methods 12
Internet Resources 13
Problems 14
Chapter 2 Strength of Mechanical Parts 15
2.1 Introduction 15
2.2 Working Capacity Calculation Criteria for Mechanical Parts 16
2.2.1 Failure form of mechanical parts 16
2.2.2 Working capacity calculation criteria 16
2.3 Common Materials for Mechanical Parts and Their Selections 18
2.3.1 Common materials for mechanical parts 19
2.3.2 Principles for selecting mechanical parts materials 22
2.4 Load and Stress Acting on Parts 24
2.4.1 Classification of load 24
2.4.2 Classification of stress 24
2.5 Strength Calculation 25
2.5.1 Strength of mechanical parts under static stress 25
2.5.2 Fatigue strength calculation of mechanical parts 27
2.5.3 Contact strength of mechanical parts 32
Internet Resources 34
Problems 34
Chapter 3 Friction, Wear and Lubrication 36
3.1 Introduction 36
3.2 Friction 37
3.2.1 Dry friction 39
3.2.2 Boundary friction (boundary lubrication) 40
3.2.3 Mixed friction (mixed lubrication) 41
3.2.4 Fluid friction (fluid lubrication) 42
3.3 Wear 42
3.3.1 Typical wear process 42
3.3.2 Types of wear 43
3.4 Lubrication 45
3.4.1 Main properties of lubricants 46
3.4.2 Viscosity law 50
3.4.3 Introduction to fluid lubrication 51
Internet Resources 52
Problems 52
Chapter 4 Threaded Joints 53
4.1 Introduction 53
4.1.1 Thread formation 53
4.1.2 Types and applications of screw 53
4.1.3 Main parameters of the thread 56
4.2 Types of Threaded Joints and Standards 57
4.2.1 Types of threaded joints 57
4.2.2 Standard threaded couplings 59
4.3 Pre-tightening and Anti-looseness of Threaded Joints 61
4.3.1 Pre-tightening of threaded joints 61
4.3.2 Anti-looseness of threaded joints 64
4.4 Strength Calculation for the Single Threaded Joints 66
4.4.1 Strength calculation of loose bolt connections 66
4.4.2 Strength calculation of tight bolt connections 67
4.4.3 Material and allowable stress of threaded couplings 73
4.5 Design and Force Analysis of Bolt Group Connections 75
4.5.1 Structural design of bolt group connections 75
4.5.2 Force analysis of bolt group connections 76
Internet Resources 79
Problems 79
Machine Elements in Mechanical Design Project 82
Chapter 5 Axle and Hub Connections 83
5.1 Key Connections 83
5.1.1 Types and applications 83
5.1.2 Selection and the strength calculation 86
5.2 Spline Connections 90
5.2.1 The type, characteristics and application of spline connections 90
5.2.2 The strength calculation of spline connections 92
5.3 Pin Connections 93
Internet Resources 95
Problems 95
Project 95
Chapter 6 Rivetings,Weldings and Bondings 97
6.1 Rivetings 97
6.1.1 Rivet joints 97
6.1.2 Failure forms and design of rivetings 98
6.2 Weldings 99
6.2.1 Types, characteristics and applications of weldings 99
6.2.2 Failure modes of welding 99
6.2.3 Design of welding parts 100
6.3 Bondings 102
6.3.1 The applications of bondings 102
6.3.2 Adhesive joints 102
6.3.3 Adhesives 103
6.3.4 Comparisons of bondings, rivetings and weldings 104
Internet Resources 104
Problems 104
Chapter 7 Power Screws 105
7.1 Types, Characteristics and Applications of Power Screws 105
7.2 Sliding Power Screws 106
7.2.1 The structure of sliding power screws 106
7.2.2 Design calculation of sliding power screws 107
7.3 Ball Screws Drives 110
7.3.1 Structure types and characteristics 110
7.3.2 Design and calculation of ball screws drives 112
Internet Resources 113
Problems 113
Project 114
Chapter 8 Belt Drives 116
8.1 Types and Characteristics of Belt Drives 116
8.1.1 Working principle and characteristics of belt drives 116
8.1.2 Types and applications of belt drives 117
8.2 Analysis of Belt Drives 118
8.2.1 Force analysis of belt drives 118
8.2.2 Stress analysis of belts 120
8.2.3 Elastic slipping and creeping of belts 121
8.3 Design Calculation of Ordinary V-belt Drives 123
8.3.1 V-belt structures 123
8.3.2 Standard for ordinary V belts 124
8.3.3 Basic rated power of single V belt 125
8.3.4 Design steps and methods of V-belt drives 127
8.4 Design of V-belt Pulleys 132
8.4.1 Design requirements for V-belt pulleys 132
8.4.2 Materials of V-belt pulleys 132
8.4.3 Structure dimension of V-belt pulleys 132
8.5 Tension and Maintenance of Belt Drives 136
8.5.1 Tension of belts 136
8.5.2 Belt maintenance 137
8.6 Introduction of Other New Belt Drives 137
8.6.1 High speed belt drives 137
8.6.2 Toothed timing belt drives 138
8.6.3 V-ribbed belt drives 139
Internet Resources 139
Problems 139
Project 140
Chapter 9 Chain Drives 142
9.1 Introduction 142
9.2 Structure of Chains 143
9.2.1 Roller chains 143
9.2.2 Silent chains 145
9.3 Structure and Material of Sprockets 146
9.3.1 Basic parameters of sprockets 147
9.3.2 Sprocket tooth profile 148
9.3.3 Structure of sprockets 149
9.3.4 Material of sprockets 149
9.4 Geometric Parameters of Chain Drives 150
9.4.1 Number of pitches 150
9.4.2 Center distance 151
9.5 Motion Characteristics of Chain Drives 151
9.5.1 Kinematics of chain drives 151
9.5.2 Dynamical loads of chain drives 153
9.6 Load Analysis of Chain Drives 154
9.7 Failure Modes and Carrying Capacity of Chain Drives 155
9.7.1 The failure modes of chain drives 155
9.7.2 Carrying capacity of chain drives 156
9.8 Chain Drives Design 158
9.8.1 Design the pitch and number of strands 158
9.8.2 Design the number of teeth in two sprockets and speed ratio 160
9.8.3 Design the number of links and center distance 161
9.8.4 Design the structure of the small sprocket 161
9.9 Layouts, Tension and Lubrication of Chain Drives 162
9.9.1 Layout of chain drives 162
9.9.2 Tension of chain drives 162
9.9.3 Lubrication of chain drives 163
Internet Resources 165
Problems 166
Project 167
Chapter 10 Gear Drives 168
10.1 Introduction 168
10.2 The Failure Modes and Design Rules of Gear Drives 170
10.2.1 Failure modes of gears 170
10.2.2 Design criteria 173
10.3 Materials and Heat Treatment of Gears 174
10.3.1 Steel 175
10.3.2 Cast iron 176
10.3.3 Bronze 176
10.3.4 Nonmetallic material 176
10.4 The Calculated Load for Gear Drives 176
10.4.1 Application factor 177
10.4.2 Dynamic factor 177
10.4.3 Axial load distribution factor 178
10.4.4 Load distribution factor across teeth 182
10.5 Strength Calculation of Standard Spur Gears 183
10.5.1 Force analysis 183
10.5.2 Calculation of spur teeth bending fatigue strength 184
10.5.3 Calculation of spur teeth contact fatigue strength 186
10.5.4 Tips for gear strength calculation 189
10.6 Design Parameters, Permissible Stress and Accuracy Choice of Gears 190
10.6.1 Design parameters 190
10.6.2 Permissible stress 191
10.6.3 The degree of gear precision 196
10.7 Strength Calculation of Standard Helical Gears 201
10.7.1 Force analysis 201
10.7.2 Calculation of helical teeth bending fatigue strength 204
10.7.3 Calculation of helical teeth contact fatigue strength 205
10.8 Strength Calculation of Standard Bevel Gears 211
10.8.1 Force analysis 211
10.8.2 Calculation of bevel teeth bending fatigue strength 212
10.8.3 Calculation of bevel teeth contact fatigue strength 212
10.9 Strength Characteristic of Modified Gears 213
10.10 Structural Design of Gears 214
10.10.1 Gear shafts 215
10.10.2 Solid gears 215
10.10.3 Web gears 216
10.10.4 Gears with crossed spokes 217
10.10.5 Combined gears 217
10.11 Lubrication of Gear Drives 218
10.11.1 Lubrication method 218
10.11.2 Lubricant selection 219
Internet Resources 220
Problems 220
Projects 222
Chapter 11 Worm Gear Transmission 224
11.1 Summary 224
11.1.1 The types of worm transmission 224
11.1.2 The characteristics of worm transmission 225
11.2 The Main Parameters and Geometric Dimensions of Common Cylindrical Worm Transmission 225
11.2.1 Main parameters of common cylindrical worm transmission 225
11.2.2 Geometric dimension calculation of worm transmission 229
11.3 Motion and Force Analysis of Worm Transmission 230
11.3.1 Motion analysis of worm transmission 230
11.3.2 Force analysis of worm transmission 231
11.4 The Failure Mode, Material and Structure of Worm Transmission 232
11.4.1 Failure forms and design criteria of worm transmission 232
11.4.2 Common materials for worm transmission 233
11.4.3 The structure of common cylindrical worm and worm wheel 233
11.5 Strength analysis of worm transmission 234
11.6 Calculation of Efficiency, Lubrication and Thermal Balance of Worm Transmission 236
11.6.1 The efficiency of worm transmission 236
11.6.2 Heat balance calculation of worm transmission 238
Internet Resources 241
Problems 241
Project 243
Chapter 12 Shafts 244
12.1 Introduction 244
12.1.1 Application and classification of shafts 244
12.1.2 Shaft materials 246
12.1.3 Introduction of design content 248
12.2 Structural Design of Shafts 249
12.2.1 The arrangement of parts on the shaft 249
12.2.2 Positioning of parts on the shaft 250
12.2.3 Determine the diameter and length of shaft segments 253
12.2.4 Processability of shaft structure 254
12.3 Strength Calculation of Shafts 254
12.3.1 Torsional strength 254
12.3.2 Bending and torsional strength 256
12.3.3 Safety factor 258
12.4 Stiffness and Vibration Stability of Shafts 259
12.4.1 Stiffness of shafts 259
12.4.2 Vibration stability and critical speed of shafts 260
12.5 Measures to Improve the Strength and Stiffness of Shafts 268
12.5.1 Reduce the stress concentration on shafts 268
12.5.2 Arrange parts on the shaft to reduce load on shafts 269
12.5.3 Improve parts structure to reduce load on shafts 270
12.5.4 Choose a proper loading mode to reduce load on shafts 270
12.5.5 Improve the surface quality to enhance the fatigue strength of shafts 271
Internet Resources 271
Problems 271
Project 273
Chapter 13 Sliding Bearings 275
13.1 Introduction 275
13.2 Type and Structure of Sliding Bearings 276
13.2.1 The classification of sliding bearings 276
13.2.2 The main structural form of radial sliding bearings 277
13.3 Sliding Bearing Material and Bearing Structure 279
13.3.1 The material of the sliding bearings 279
13.3.2 Bearing structure 283
13.4 Lubrication of Sliding Bearings 285
13.4.1 The selection of lubricant 285
13.4.2 Lubrication methods 288
13.5 Calculation of Non-liquid-lubricated Sliding Bearings 289
13.5.1 Radial sliding bearings 290
13.5.2 Thrust sliding bearings 291
13.6 Design and Calculation of Hydrodynamic Lubrication Radial Sliding Bearings 292
13.6.1 Basic equation of fluid dynamic lubrication 292
13.6.2 Oil wedge bearing mechanism 294
13.6.3 Establishment process of liquid dynamic lubrication state 295
13.6.4 Geometric relations and bearing capacity of radial sliding bearings 295
13.6.5 Bearing parameter selection 299
13.7 Introduction to Other Types of Sliding Bearings 300
13.7.1 Multi-oil wedge sliding bearings 300
13.7.2 Hydro-static bearings 302
13.7.3 Gas bearings 303
13.7.4 Magnetic bearings 303
Internet Resources 304
Problems 304
Chapter 14 Rolling-Element Bearings 306
14.1 Introduction 306
14.1.1 Structure of rolling-element bearings 306
14.1.2 Material of rolling-element bearings 307
14.1.3 Characteristics of rolling-element bearings 307
14.2 Types and Selection of Rolling-Element Bearings 308
14.2.1 Types and characteristics of rolling-element bearings 308
14.2.2 Code of rolling-element bearings 311
14.2.3 Selection of rolling-element bearings 314
14.3 Force Analysis, Failure Modes and Calculation Criterion of Rolling-Element Bearings 315
14.3.1 Load distribution of rolling-element bearings 315
14.3.2 Load and stress of bearing elements 319
14.3.3 Failure modes and calculation criteria of rolling-element bearings 320
14.4 Dynamic Load and Life Calculation of Rolling Bearings 321
14.4.1 Basic rating life and basic dynamic load rating 321
14.4.2 Dynamic equivalent load 321
14.4.3 Fatigue life calculation of rolling bearings 322
14.4.4 Thrust load calculation of angular contact ball bearings and tapered roller bearings 323
14.5 Limit Speed of Rolling Bearings 325
14.6 Combined Structural Design of Rolling Bearings 328
14.6.1 Mounting arrangement of rolling bearings 329
14.6.2 Axial fixation of rolling bearings 330
14.6.3 Stiffness of the supporting structure and concentricity of the housing hole 332
14.6.4 Adjustment of rolling bearing clearance and axial position of the shaft 332
14.6.5 Rolling bearing fit 333
14.6.6 Preloading of rolling bearings 334
14.6.7 Assembly and disassembly of rolling bearings 335
14.6.8 Lubrication of rolling bearings 336
14.6.9 Seals of rolling bearings 337
Internet Resources 339
Problems 339
Project 340
Chapter 15 Couplings, Clutches and Brakes 342
15.1 Introduction 342
15.2 Couplings 343
15.2.1 Type, structure and characteristics of couplings 343
15.2.2 Coupling selection 350
15.3 Clutches 352
15.3.1 Mechanical clutches 352
15.3.2 Safety clutches 355
15.4 Brakes 355
15.4.1 Band brakes 355
15.4.2 Disc brakes 356
Internet Resources 356
Problems 356
Project 357
Appendix Glossary and Index 358
References 371
