Nomenclature... xi Hydraulic Laws, Theorems, and Equations...xii 1 Introduction 1.1 Component Design Perspective...1 1.2 Hydraulic Power Evolution...2 1.3 Hydraulic Applications...6 1.4 Component Design Rationale...8 Design Considerations...9 1.5 Why Computerized Component Design?...9 Example of Relief Valve Design...10 Example of Electrohydraulic Servo Valve...15 2 Fundamental Fluid Power Engineering 2.1 Introduction...19 2.2 Engineering System of Units...19 2.3 Behavior of Fluid in a System...23 2.4 Viscosity of Fluids...27 2.5 Pressure...30 2.6 Flow...33 2.7 Conduit Flow Models...35 2.8 Orifice Flow Models...37 2.9 Energy and Power...43 2.10 Design Safety Factors...44 2.11 Hydraulic Laws, Theorems, and Equations...46
iv Hydraulic Component Design and Selection 3 Linear Actuators 3.1 Function and Configuration...47 3.2 Cylinder Nomographs...48 3.3 Hydraulic Cylinders...52 Cylinder Performance Model...55 3.4 Hydraulic Cylinder Cushioning...59 Cylinder Cushioning Model...64 3.5 Hydraulic Cylinder Design Considerations...76 Material Selection...77 Cylinder Wall Thickness...77 Diametral Expansion...80 Cylinder Body Styles...80 Cylinder Heads and Tie-rod...81 Piston-Rod Diameter...83 3.6 Hydraulic Cylinder Structural Integrity...87 3.7 Hydraulic Cylinder Dynamics...99 3.8 Hydraulic Cylinder Selection...100 3.9 General Selection Considerations...104 4 Rotary Actuators 4.1 Introduction...107 4.2 Hydraulic Rotary Motors...110 Positive Displacement Motor Model...112 4.3 Hydraulic Motor Selection...124 4.4 Limited Rotation Actuators...126 4.5 Oscillating Motor Applications...129 5 Fluid Distribution 5.1 Fluid Distribution Function...131 5.2 Directional Control Valves...133 Directional Control Valve Selection Factors...140 5.3 Check Valves...142 Direct Acting Check Valve Model...143 Pilot Operated Check Valve Model...145 Pilot Check Valve Application Study...147 5.4 Shuttle Valves...152 5.5 Spool Valve Characteristics...154 Pressure-Flow Models...154
v Spool Lap Configurations...157 Flow Gain...157 Center Position Leakage...158 Pressure Sensitivity...160 Pressure-Flow Metering Characteristics...161 Closed Center Spool Valve Model...161 Open Center Spool Valve Model...162 Motor (Float) Spool Valve Model...166 5.6 Spool Valve Selection...167 5.7 Valve Design Considerations...172 Spool Valves...173 Poppet Valves...175 Flow Forces...177 5.8 Solenoid Valves...183 5.9 Hydraulic Fuses and Circuit Protectors...188 6 Pressure Regulation 6.1 Pressure Regulation Function...191 6.2 Pressure Control Selection Factors...193 6.3 Relief and Safety Valves...194 Safety Valves...196 System Protectors...196 Direct Acting Relief Valves...197 Differential Pressure Relief Valve...197 Pilot-Operated Vent-Type Relief Valve...198 Relief Valve Characteristics...199 Cross-Port Relief Valves...202 Relief Valve Assessment and Selection...203 Relief Valve Model...205 Surge Pressure Analysis...212 6.4 Sequence Valves...213 6.5 Counterbalance Valves...216 Direct Acting Counterbalance Valve...217 Remotely Controlled Counterbalance Valve...219 Over-center Valve...220 Brake Valve...221 Counterbalance Valve Model...222 6.6 Unloading Valves...232 Differential Unloading Relief Valve...233 Unloading Valve Characteristics...234 6.7 Reducing Valves...236 Reducing Valve Model...240 Reducing Relief Valve...244
vi Hydraulic Component Design and Selection 6.8 Valve Noise and Cavitation...251 7 Flow Regulation 7.1 Flow Regulation Function...257 7.2 Uncompensated Flow Controls...261 Flow Restrictor Model...264 7.3 Deceleration Valve...266 7.4 Compensated Flow Control...268 Pressure Compensated Flow Control Valve Model...272 7.5 Bypass Flow Regulator...276 7.6 Priority Valve...279 7.7 Flow Divider and Combiner Valves...281 Flow Divider Model...283 7.8 Positive-Displacement-Metering Valve...288 7.9 Flow Control Circuits...288 Meter-Out Circuit...289 Meter-In Circuit...291 Bleed-Off or Bypass Circuit...293 7.10 Valve Selection and Specification...300 8 Cartridge Valve Technology 8.1 Cartridge Valve Perspective...303 8.2 Poppet-Type Cartridges...306 Pilot Pressure Sources...309 Directional Control Configurations...312 Pressure Control Cartridge Valves...314 8.3 Spool-Type Cartridge Valves...315 8.4 Cartridge Valve Models...318 Pilot-to-Close Model...318 Pilot-to-Open Model...320 8.5 Sizing of Cartridge Valves...321 8.6 Cartridge Manifold Design...324 8.7 Applications...325 Regenerative Machine Tool Feed System...325 Plastic Injection Process Control System...328 9 Hydraulic Power Sources 9.1 The Energy Question...333
vii 9.2 Prime Mover Considerations...335 Use of Hydrostatic Transmissions...339 9.3 Hydrostatic Power Generation...341 Gear Pumps...342 Vane Pumps...344 Piston Pumps...346 Screw Pumps...349 Lobe Pumps...349 9.4 Pumping Models...350 Gear Pump Model...350 Vane Pump Models...356 Axial Piston Pump Models...359 Radial Piston Pump Model...366 Check Valve Piston Pump Model...367 9.5 Pump Characteristics...368 9.6 Pump Application Factors...372 9.7 Functional Aspects of Pumps...376 9.8 Fixed Displacement Pump Models...381 Lumped Coefficient Model...381 Performance Coefficient Model...383 Pump Performance Testing...384 Determination of Pump Displacement (D p ) and Slip Coefficient (C s )...385 Determination of Viscous Shear Coefficient (C v )...386 Determination of Mechanical Friction Coefficient (C f ) and Breakaway Torque (T c )...387 9.9 Noise in Pump Systems...397 9.10 Environmental Aspects of Pumps...399 9.11 Booster Pumps...400 Centrifugal Pump...400 Eductor or Jet Pump...410 10 Energy Storage and Transformation 10.1 Introduction...417 10.2 Energy Storage Accumulators...418 Weight-Loaded Accumulators...419 Spring-Loaded Accumulators...419 Gas-Loaded Accumulators...420 10.3 Gas-loaded Accumulator Sizing Criteria...421 10.4 Accumulator Selection and Application...438 Auxiliary Power Source...438 Flow Pulsation Dampener...440 Pressure Surge Absorber...442 Temperature Change Considerations...446
viii Hydraulic Component Design and Selection 10.5 Accumulator Assessment...449 10.6 Energy Transformation Devices...450 10.7 Intensifier Application Factors...455 10.8 Intensifier Assessment and Selection...458 11 The Conduit System 11.1 The Role and Types of Conduits...461 11.2 Connector Seals...462 11.3 Conduit Connectors...463 11.4 An Overtorqued Connector Case...468 11.5 Rigid Conduit Piping...472 11.6 Rigid Conduit Tubing...474 11.7 Flexible Conduit Hose...481 Improper Hose Application...484 Improper Hose Assembly...485 Improper Hose Installation...489 Environmental Protection...491 Severe Operational Duty Cycle...492 Corrosivity of Elastomers...492 Damaged/Faulty Hose Assembly...493 Hose Defectively Manufactured...493 11.8 Manifolding and Modularizing...498 En Bloc Manifolding...500 Stacked Valve Method...501 Stacked Subplate Method...501 Drilled Plate Method...501 Sandwich Plate Manifold Method...502 11.9 Energy Losses in Conduit Systems...502 Friction Losses...502 Minor Losses...503 Equivalent Length...508 Net Positive Suction Head (NPSH)...514 12 Seals for Hydraulics 12.1 Introduction...521 12.2 Types of Seals...523 Contact Seals...523 Clearance Seals...527 Gasket Seal...528 12.3 Mechanics of Sealing...529 12.4 Elastomer Technology...532
ix Abrasion Resistance...533 Oil/Seal Compatibility...534 Compression Set...534 Corrosivity...534 Material Creep...534 Crystallization...535 Elasticity...535 Extrusion...535 Fatigue...535 Friction...535 Hardness...536 Stress Relaxation...536 Tear Resistance...536 Tensile Strength...537 Thermal Expansion...537 Permeability...538 Aging...538 12.5 Seal Design and Selection Notes...538 Lip Seal Notes...538 O-ring Notes...539 Face Seal Notes...540 Elastomer/Design Interaction...542 12.6 Linear Seal Considerations...543 12.7 Cylinder and Piston O-ring Seal Force Model...548 12.8 Hydraulic Seal Models...554 Theory of Hydraulic Sealing...554 Reciprocating Seal Model...556 Rotary Seal Model...562 Hydraulic Sealing Criteria...564 Appendix A Glossary of Hydraulic Terms...567 Appendix B Fluid Power Symbols...589 Appendix C Hydraulic Test Standards...601 Appendix D FPRC/OSU Orifice Flow Nomograph...613 Appendix E Tables of Conversion Factors...617 Bibliography...621 Index...627