Andrea Vacca - Hydraulic Fluid Power

1 Cover

2 Title Page Hydraulic Fluid Power Fundamentals, Applications, and Circuit Design Andrea Vacca Maha Fluid Power Research Center Purdue University West Lafayette, Indiana, United States Germano Franzoni Global Mobile Systems, Parker Hannifin Elk Grove Village, Illinois, United States

3 Copyright

4 Preface

5 Acknowledgments

6 Part I: Fundamental Principles Chapter 1: Introduction to Hydraulic Control Technology 1.1 Historical Perspective 1.2 Fluid Power Symbology and Its Evolution 1.3 Common ISO Symbols Problems 2 Hydraulic Fluids 2.1 Ideal vs. Actual Hydraulic Fluids 2.2 Classification of Hydraulic Fluids 2.3 Physical Properties of Hydraulic Fluids 2.4 Fluid Compressibility: Bulk Modulus 2.5 Fluid Density 2.6 Fluid Viscosity2.7 Entrained Air, Gas Solubility, and Cavitation 2.8 Contamination in Hydraulic Fluids 2.9 Considerations on Hydraulic Reservoirs Problems Notes Chapter 3: Fundamental Equations 3.1 Pascal's Law 3.2 Basic Law of Fluid Statics 3.3 Volumetric Flow Rate 3.4 Conservation of Mass 3.5 Bernoulli's Equation 3.6 Hydraulic Resistance 3.7 Stationary Modeling of Flow Networks 3.8 Momentum Equation Problems Notes Chapter 4: Orifice Basics 4.1 Orifice Equation 4.2 Fixed and Variable Orifices 4.3 Power Loss in Orifices 4.4 Parallel and Series Connections of Orifices 4.5 Functions of Orifices in Hydraulic Systems Problems Notes Chapter 5: Dynamic Analysis of Hydraulic Systems 5.1 Pressure Build‐up Equation: Hydraulic Capacitance 5.2 Fluid Inertia Equation: Hydraulic Inductance 5.3 Modeling Flow Network: Dynamic Considerations 5.4 Damping Effect of Hydraulic Accumulators Problems References Note

7 Part II: Hydraulic Components Chapter 6: Hydrostatic Pumps and Motors 6.1 Introduction 6.2 The Ideal Case 6.3 General Operating Principle 6.4 ISO Symbols 6.5 Ideal Equations 6.6 The Real Case 6.7 Losses in Pumps and Motors 6.8 Volumetric and Hydromechanical Efficiency 6.9 Design Types Problems Notes Chapter 7: Hydraulic Cylinders 7.1 Classification 7.2 Cylinder Analysis 7.3 Ideal vs. Real Cylinder 7.4 Telescopic Cylinders Problems Notes Chapter 8: Hydraulic Control Valves 8.1 Spring Basics 8.2 Check and Shuttle Valves 8.3 Pressure Control Valves 8.4 Flow Control Valves 8.5 Directional Control Valves 8.6 Servovalves Problems Chapter 9: Hydraulic Accumulators 9.1 Accumulator Types 9.2 Operation of Gas‐charged Accumulators 9.3 Typical Applications 9.4 Equation and Sizing Problems References Note

8 Part III: Actuator Control Concepts Chapter 10: Basics of Actuator Control 10.1 Control Methods: Speed, Force, and Position Control 10.2 Resistive and Overrunning Loads Problems Note Chapter 11: General Concepts for Controlling a Single Actuator 11.1 Supply and Control Concepts 11.2 Flow Supply – Primary Control 11.3 Flow Supply – Metering Control 11.4 Flow Supply – Secondary Control 11.5 Pressure Supply – Primary Control 11.6 Pressure Supply – Metering Control 11.7 Pressure Supply – Secondary Control 11.8 Additional Remarks Note Chapter 12: Regeneration with Single Rod Actuators 12.1 Basic Concept of Regeneration 12.2 Actual Implementation Problems References

9 Part IV: Metering Controls for a Single Actuator Chapter 13: Fundamentals of Metering Control 13.1 Basic Meter‐in and Meter‐out Control Principles 13.2 Actual Metering Control Components 13.3 Use of Anticavitation Valves for Unloaded Meter‐out Problems Notes Chapter 14: Load Holding and Counterbalance Valves 14.1 Load‐holding Valves 14.2 Counterbalance Valves Problems Notes Chapter 15: Bleed‐off and Open Center Systems 15.1 Basic Bleed‐off and Open Center Circuits 15.2 Bleed‐off Circuit Operation 15.3 Basic Open Center System 15.4 Advanced Open Center Control Architectures Problems Notes Chapter 16: Load Sensing Systems 16.1 Basic Load Sensing Control Concept 16.2 Load Sensing System with Fixed Displacement Pump 16.3 Load Sensing Valve 16.4 Load Sensing System with Variable Displacement Pump 16.5 Load Sensing Pump 16.6 Load Sensing Solution with Independent Metering Valves 16.7 Electronic Load Sensing (E‐LS) Problems Notes Chapter 17: Constant Pressure Systems 17.1 Constant Pressure System with Variable Displacement Pump 17.2 Constant Pressure System with Unloader (CPU) 17.3 Constant Pressure System with Fixed Displacement Pump 17.4 Application to Hydraulic Braking Circuits Problems References Notes

10 Part V: Metering Controls for Multiple Actuators Chapter 18: Basics of Multiple Actuator Systems 18.1 Actuators in Series and in Parallel 18.2 Elimination of Load Interference in Parallel Actuators 18.3 Synchronization of Parallel Actuators Through Flow Dividers Problems Note Chapter 19: Constant Pressure Systems for Multiple Actuators 19.1 Basic Concepts for a Multi‐Actuator Constant Pressure System 19.2 Complete Schematic for a Multi‐Actuator Constant Pressure System Problems Chapter 20: Open Center Systems for Multiple Actuators 20.1 Parallel Open Center Systems 20.2 Tandem and Series Open Center Systems 20.3 Advanced Open Center Circuit for Multiple Actuators: The Case of Excavators Problems Notes Chapter 21: Load Sensing Systems for Multiple Actuators 21.1 Load Sensing Systems Without Pressure Compensation (LS) 21.2 Load Sensing Pressure Compensated Systems (LSPC) 21.3 Flow Saturation and Flow Sharing in LS Systems 21.4 Pre‐ vs. Post‐compensated Comparison 21.5 Independent Metering Systems with Load Sensing Problems Notes Chapter 22: Power Steering and Hydraulic Systems with Priority Function 22.1 Hydraulic Power Steering 22.2 Classification of Hydraulic Power Steering Systems 22.3 Hydromechanical Power Steering 22.4 Hydrostatic Power Steering 22.5 Priority Valves Problems References

11 Part VI: Hydrostatic Transmissions and Hydrostatic Actuators Chapter 23: Basics and Classifications 23.1 Hydrostatic Transmissions and Hydrostatic Actuators 23.2 Primary Units for Hydrostatic Transmissions and Hydrostatic Actuators 23.3 Over‐center Variable Displacement Pump 23.4 Typical Applications 23.5 Classification Summary Note Chapter 24: Hydrostatic Transmissions 24.1 Main Parameters for a Hydrostatic Transmission 24.2 Theoretical Layouts 24.3 Open Circuit Hydrostatic Transmissions 24.4 Closed Circuit Hydrostatic Transmissions 24.5 Closed Circuit Displacement Regulators Problems Notes Chapter 25: Hydrostatic Transmissions Applied to Vehicle Propulsion 25.1 Basic of Vehicle Transmission 25.2 Classification for Variable Ratio Transmission Systems 25.3 Power‐split Transmissions 25.4 Hybrid Transmissions 25.5 Sizing Hydrostatic Transmissions for Propel Applications Problems Note Chapter 26: Hydrostatic Actuators 26.1 Open Circuit Hydrostatic Actuators 26.2 Closed Circuit Hydrostatic Actuators 26.3 Further Considerations on the Charge Pump and the Accumulator 26.4 Final Remarks on Hydrostatic Actuators Note Chapter 27: Secondary Controlled Hydrostatic Transmissions 27.1 Basic Implementation 27.2 Secondary Control Circuit with Tachometric Pump 27.3 Secondary Control Circuit with Tachometric Pump and Internal Force Feedback 27.4 Secondary Control Circuit with Electronic Control 27.5 Multiple Actuators Problems References Notes

12 Appendix A: Appendix APrime Movers and Their Interaction with the Hydraulic Circuit Objectives A.1 Corner Power Method and its Limitations A.2 Diesel Engine and its Interaction with a Hydraulic Pump A.3 Electric Prime Movers A.4 Power Limitation in Hydraulic Pumps References Note

13 Index

14 End User License Agreement

1 Chapter 2 Table 2.1 Correspondence between the DIN and the ISO standard for mineral oil... Table 2.2 Comparison between different hydraulic fluids. Table 2.3 Typical values for fluid density. Table 2.4 Fluid parameters used for the plot of Figure 2.4. Table 2.5 ISO classes for hydraulic oils according to the viscosity grade. Table 2.6 Typical values for the viscosity index. Table 2.7 Typical clearances in hydraulic components. Table 2.8 Codification of the fluid cleanliness according to ISO 4406, with t... Table 2.9 Code for the cleanliness level of a hydraulic fluid according to IS... Table 2.10 Suggested cleanliness code for typical hydraulic components accord... Table 2.11 Typical pressure drops in filters depending on the filter installa...