Nomenclature... xi Hydraulic Laws, Theorems, and Equations...xii

Transcription

1 Nomenclature... xi Hydraulic Laws, Theorems, and Equations...xii 1 Introduction 1.1 Component Design Perspective Hydraulic Power Evolution Hydraulic Applications Component Design Rationale...8 Design Considerations Why Computerized Component Design?...9 Example of Relief Valve Design...10 Example of Electrohydraulic Servo Valve Fundamental Fluid Power Engineering 2.1 Introduction Engineering System of Units Behavior of Fluid in a System Viscosity of Fluids Pressure Flow Conduit Flow Models Orifice Flow Models Energy and Power Design Safety Factors Hydraulic Laws, Theorems, and Equations...46

2 iv Hydraulic Component Design and Selection 3 Linear Actuators 3.1 Function and Configuration Cylinder Nomographs Hydraulic Cylinders...52 Cylinder Performance Model Hydraulic Cylinder Cushioning...59 Cylinder Cushioning Model 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 Hydraulic Cylinder Structural Integrity Hydraulic Cylinder Dynamics Hydraulic Cylinder Selection General Selection Considerations Rotary Actuators 4.1 Introduction Hydraulic Rotary Motors Positive Displacement Motor Model Hydraulic Motor Selection Limited Rotation Actuators Oscillating Motor Applications Fluid Distribution 5.1 Fluid Distribution Function Directional Control Valves Directional Control Valve Selection Factors Check Valves Direct Acting Check Valve Model Pilot Operated Check Valve Model Pilot Check Valve Application Study Shuttle Valves Spool Valve Characteristics Pressure-Flow Models...154

3 v Spool Lap Configurations Flow Gain Center Position Leakage Pressure Sensitivity Pressure-Flow Metering Characteristics Closed Center Spool Valve Model Open Center Spool Valve Model Motor (Float) Spool Valve Model Spool Valve Selection Valve Design Considerations Spool Valves Poppet Valves Flow Forces Solenoid Valves Hydraulic Fuses and Circuit Protectors Pressure Regulation 6.1 Pressure Regulation Function Pressure Control Selection Factors Relief and Safety Valves Safety Valves System Protectors Direct Acting Relief Valves Differential Pressure Relief Valve Pilot-Operated Vent-Type Relief Valve Relief Valve Characteristics Cross-Port Relief Valves Relief Valve Assessment and Selection Relief Valve Model Surge Pressure Analysis Sequence Valves Counterbalance Valves Direct Acting Counterbalance Valve Remotely Controlled Counterbalance Valve Over-center Valve Brake Valve Counterbalance Valve Model Unloading Valves Differential Unloading Relief Valve Unloading Valve Characteristics Reducing Valves Reducing Valve Model Reducing Relief Valve...244

4 vi Hydraulic Component Design and Selection 6.8 Valve Noise and Cavitation Flow Regulation 7.1 Flow Regulation Function Uncompensated Flow Controls Flow Restrictor Model Deceleration Valve Compensated Flow Control Pressure Compensated Flow Control Valve Model Bypass Flow Regulator Priority Valve Flow Divider and Combiner Valves Flow Divider Model Positive-Displacement-Metering Valve Flow Control Circuits Meter-Out Circuit Meter-In Circuit Bleed-Off or Bypass Circuit Valve Selection and Specification Cartridge Valve Technology 8.1 Cartridge Valve Perspective Poppet-Type Cartridges Pilot Pressure Sources Directional Control Configurations Pressure Control Cartridge Valves Spool-Type Cartridge Valves Cartridge Valve Models Pilot-to-Close Model Pilot-to-Open Model Sizing of Cartridge Valves Cartridge Manifold Design Applications Regenerative Machine Tool Feed System Plastic Injection Process Control System Hydraulic Power Sources 9.1 The Energy Question...333

5 vii 9.2 Prime Mover Considerations Use of Hydrostatic Transmissions Hydrostatic Power Generation Gear Pumps Vane Pumps Piston Pumps Screw Pumps Lobe Pumps Pumping Models Gear Pump Model Vane Pump Models Axial Piston Pump Models Radial Piston Pump Model Check Valve Piston Pump Model Pump Characteristics Pump Application Factors Functional Aspects of Pumps Fixed Displacement Pump Models Lumped Coefficient Model Performance Coefficient Model Pump Performance Testing Determination of Pump Displacement (D p ) and Slip Coefficient (C s ) Determination of Viscous Shear Coefficient (C v ) Determination of Mechanical Friction Coefficient (C f ) and Breakaway Torque (T c ) Noise in Pump Systems Environmental Aspects of Pumps Booster Pumps Centrifugal Pump Eductor or Jet Pump Energy Storage and Transformation 10.1 Introduction Energy Storage Accumulators Weight-Loaded Accumulators Spring-Loaded Accumulators Gas-Loaded Accumulators Gas-loaded Accumulator Sizing Criteria Accumulator Selection and Application Auxiliary Power Source Flow Pulsation Dampener Pressure Surge Absorber Temperature Change Considerations...446

6 viii Hydraulic Component Design and Selection 10.5 Accumulator Assessment Energy Transformation Devices Intensifier Application Factors Intensifier Assessment and Selection The Conduit System 11.1 The Role and Types of Conduits Connector Seals Conduit Connectors An Overtorqued Connector Case Rigid Conduit Piping Rigid Conduit Tubing Flexible Conduit Hose Improper Hose Application Improper Hose Assembly Improper Hose Installation Environmental Protection Severe Operational Duty Cycle Corrosivity of Elastomers Damaged/Faulty Hose Assembly Hose Defectively Manufactured Manifolding and Modularizing En Bloc Manifolding Stacked Valve Method Stacked Subplate Method Drilled Plate Method Sandwich Plate Manifold Method Energy Losses in Conduit Systems Friction Losses Minor Losses Equivalent Length Net Positive Suction Head (NPSH) Seals for Hydraulics 12.1 Introduction Types of Seals Contact Seals Clearance Seals Gasket Seal Mechanics of Sealing Elastomer Technology...532

7 ix Abrasion Resistance Oil/Seal Compatibility Compression Set Corrosivity Material Creep Crystallization Elasticity Extrusion Fatigue Friction Hardness Stress Relaxation Tear Resistance Tensile Strength Thermal Expansion Permeability Aging Seal Design and Selection Notes Lip Seal Notes O-ring Notes Face Seal Notes Elastomer/Design Interaction Linear Seal Considerations Cylinder and Piston O-ring Seal Force Model Hydraulic Seal Models Theory of Hydraulic Sealing Reciprocating Seal Model Rotary Seal Model Hydraulic Sealing Criteria Appendix A Glossary of Hydraulic Terms Appendix B Fluid Power Symbols Appendix C Hydraulic Test Standards Appendix D FPRC/OSU Orifice Flow Nomograph Appendix E Tables of Conversion Factors Bibliography Index...627