Shaft seals for dynamic applications

Shaft Seals for Dynamic Applications......Page 1
Preface......Page 3
Contents......Page 6
References......Page 10
1.1 SEAL TYPES......Page 22
1.2 SELECTING A SEAL TYPE FOR AN APPLICATION......Page 26
1.3 RADIAL LIP SEALS......Page 31
2.1 POLYMER SELECTION......Page 33
2.1.3 Polyacrylic Polymers ACM......Page 34
2.1.7 Fluoroelastomer FKM......Page 35
2.2 TESTING OF UNVULCANIZED ELASTOMERIC MATERIALS......Page 36
2.2.1 Rotating Disk Viscometer Mooney Machine......Page 37
2.2.2 Oscillating Disk Rheometer......Page 41
2.3 TESTING VULCANIZED ELASTOMERIC MATERIALS......Page 42
2.3.1 Hardness ASTM D2240 and D1415......Page 44
Wallace Microhardness Units......Page 47
2.3.2 Tensile Strength, Tensile Stress Modulus, and Elongation ASTM D412......Page 48
2.3.3 Compression Set ASTM D395 and D1229......Page 49
2.3.5 Abrasion Resistance ASTM D1630, D2228, and D3389......Page 52
2.3.6 Tear Strength ASTM D624......Page 53
2.3.7 Adhesion ASTM D413 and D429......Page 54
2.3.8 Permeability......Page 55
2.3.9 Cold Test Procedures ASTM D1053 and D2137......Page 56
2.3.10 Ozone Resistance ASTM D470 and D1149......Page 58
2.3.11 Heat Aging ASTM D573......Page 59
2.3.12 Aging in Oils and Chemicals......Page 60
2.3.13 Standard ASTM Classification System for Elastomeric Materials......Page 83
3.1 LUBRICATION THEORY......Page 87
3.2.2 Color ASTM D1500......Page 90
3.2.4 Gravity or Density ASTM D287, D1298, and D2501......Page 92
3.2.5 Molecular Analysis ASTM D2007......Page 93
3.2.8 Viscosity ASTM D445 and D2270......Page 94
3.2.9 Base Oil Selection......Page 96
3.3 ADDITIVES......Page 97
3.3.3 Dispersants and Detergents......Page 98
3.3.8 Pour Point Depressants......Page 100
3.3.11 Viscosity Index Improver......Page 101
3.4.1 Grease Properties......Page 102
3.4.2 NLGI ASTM Designation, Description, and Performance Requirements......Page 105
3.4.3 Application Guide......Page 107
3.5.1 API Service Classification......Page 108
3.5.3 Fuel Economy......Page 109
3.5.5 API Symbol......Page 116
3.6.1 API Service Classifications......Page 118
3.6.2 SAE Viscosity Grades......Page 119
3.7.2 Properties of Automatic Transmission Fluids SAE J311......Page 120
3.8.1 Synthetic Oils......Page 121
3.8.3 Seal Selection......Page 122
3.9.1 Nitrite NBR in Engine Transmission and Gear Oils......Page 124
3.9.2 Various Elastomers in Additives......Page 128
3.9.5 Effect of Humidity on Polyacrylate Seals......Page 129
4.1 ROTARY SHAFT SEAL EVOLUTION......Page 138
4.2 SEAL ELEMENT GEOMETRY......Page 141
4.2.1 Seal Cross Section......Page 142
4.2.4 Lip/Shaft Contact Region......Page 144
4.3.1 Springless Seals......Page 145
4.3.2 Spring-Loaded Seals......Page 147
4.3.4 Unitized Seals......Page 148
4.3.5 Hydrodynamic Seals......Page 152
4.4.1 Materials......Page 153
4.4.2 Case Design Configurations......Page 155
4.4.3 Seal Case Gaskets......Page 157
5.1 SEAL ENVELOPE DIMENSIONS......Page 159
5.2.1 Shaft Material and Geometry......Page 161
5.2.2 Shaft Finish Specification......Page 163
5.3.1 Bore Material and Geometry......Page 164
5.4.1 Dimensional Tolerances......Page 165
5.5.1 Garter Spring Dimensions and Materials......Page 168
5.5.2 Spring Load......Page 173
5.6.1 Storage and Handling......Page 174
5.6.2 Preinstallation Practices......Page 175
5.6.3 Installation Tools......Page 176
5.6.4 Postinstallation Practices......Page 180
6.1 HISTORICAL OVERVIEW......Page 181
6.2 MICROSCOPIC SEALING MECHANISM......Page 185
6.3 MACROSCOPIC SEALING MECHANISM......Page 191
7.2 MEASURING UNDERLIP TEMPERATURE......Page 197
7.3 MEASURING SEAL TORQUE AND POWER......Page 199
7.4.1 Spiral Groove Shaft......Page 212
7.4.3 Backward Test......Page 213
7.4.4 Oil Drop Test......Page 214
7.4.5 Pump Rate versus Duty Parameter......Page 216
7.5.1 Laboratory Machines for Endurance Testing......Page 217
7.5.2 Histograms, Success Testing, and Reliability......Page 221
7.5.3 Weibull Statistics for Seal Tests......Page 226
7.5.4. Success Versus Weibull Testing......Page 233
8.1 BASELINE TEST CONDITIONS......Page 236
8.2 EFFECT OF SUMP TEMPERATURE ON SEAL PERFORMANCE......Page 237
8.3 EFFECT OF ECCENTRICITY ON SEAL PERFORMANCE......Page 243
8.4 EFFECT OF SEAL COCKING ON SEAL PERFORMANCE......Page 244
8.5 EFFECT OF LUBRICANTS ON SEAL PERFORMANCE......Page 246
8.6 EFFECT OF LUBRICANT FILL LEVELON SEAL PERFORMANCE......Page 253
8.7 EFFECT OF PRESSURE ON SEAL PERFORMANCE......Page 257
8.8 EFFECT OF EXTERNAL CONTAMINANTS ON SEAL PERFORMANCE......Page 259
9.1 BASELINE TEST CONDITIONS......Page 265
9.2 EFFECT OF SHAFT SIZE ON SEAL PERFORMANCE......Page 267
9.3 EFFECT OF GARTER SPRING TENSION AND R VALUE ON SEAL PERFORMANCE......Page 268
9.4 EFFECT OF SPRUNG INTERFERENCE ON SEAL PERFORMANCE......Page 272
9.5 SEAL DESIGN AND MATERIAL CONSIDERATIONS FOR LOW-TEMPERATURE OPERATION......Page 275
9.6 THE EFFECT OF SEAL CROSS-SECTIONAL DESIGN IN PRESSURE APPLICATIONS......Page 276
9.7 THE EFFECT OF SECONDARY LIP DESIGN ON SEAL PERFORMANCE IN DUST ENVIRONMENT......Page 277
10.1 THE SEALING SYSTEM......Page 286
10.2.1 Bore Inspection Before Seal Removal......Page 291
10.2.2 Seal Inspection Before Seal Removal......Page 292
10.3.2 Bore and Housing Inspection After Seal Is Removed......Page 295
10.3.3 Seal Inspection After Removal......Page 300
10.3.4 Shaft Inspection After Seal Is Removed......Page 314
10.4 LEAKAGE ANALYSIS: LUBRICANT EVALUATION......Page 318
10.5 SUMMARY......Page 319
11.1 STANDARD SEALS......Page 322
11.2 DIESEL ENGINE CRANKSHAFT......Page 329
11.3 AUTOMOTIVE ENGINE CRANKSHAFT SEALS......Page 335
11.4 PINION SEALS......Page 340
11.5 TRUCK AND AUTOMOTIVE WHEEL SEALS......Page 347
11.6 TRACKED VEHICLES......Page 353
12.1 OVERALL PROCESS FLOW FOR NONELASTOMERIC SEALS......Page 355
12.2 OVERALL PROCESS FLOW FOR ELASTOMERIC SEALS......Page 356
12.3 MIXING ELASTOMERIC COMPOUNDS......Page 357
12.4 EXTRUSION OF RUBBER PREPS......Page 368
12.5 CASE MANUFACTURE AND PREPARATION FOR BONDING......Page 370
12.6.1 Mold Design......Page 372
12.6.2 Molding......Page 376
12.7 FINISHING OPERATIONS......Page 384
13.1 RADIAL LIP SEAL CHARACTERISTICS......Page 387
13.2.1 Light Box Test Procedure......Page 391
13.2.2 Transparent Shaft Procedure......Page 392
13.2.3 Air Leakdown......Page 393
13.4 SEAL SPRUNG AND UNSPRUNG UP INNER DIAMETER......Page 394
13.4.3 Production Method--Air Flow......Page 396
13.6 RADIALWALL VARIATION......Page 397
13.8 SPRING AXIAL POSITION......Page 399
13.9 CONTACT LINE HEIGHT VARIATION......Page 400
13.12 RADIAL LOAD......Page 401
13.13.1 Types of Seal Coatings......Page 406
Mechanical......Page 408
13.14 SEAL CROSS SECTION MEASUREMENT......Page 409
13.15 BOND TESTS......Page 412
13.16 VISUAL VARIATION......Page 413
13.17 GARTER SPRING MEASUREMENTS......Page 417
13.18 FUNCTIONAL BENCH TESTS......Page 418
13.19 SHAFT LEAD MEASUREMENT......Page 423
13.20 MEASURING SHAFT SURFACE FINISH......Page 428
APPENDIX A: Radial Lip Seal Terminology......Page 431
APPENDIX B: Elastomer Terminology......Page 443
APPENDIX C: Lubricant Terminology......Page 448
APPENDIX D: System of Units and Conversion Tables......Page 466
APPENDIX E: Nomenclature......Page 475