Hydraulic Fluid Power: Fundamentals, Applications, and Circuit Design

Cover
Title Page
Copyright
Contents
Preface
Acknowledgments
Part I Fundamental Principles
	Objectives
	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
	Chapter 2 Hydraulic Fluids
		2.1 Ideal vs. Actual Hydraulic Fluids
		2.2 Classification of Hydraulic Fluids
			2.2.1 Mineral Oils (H)
			2.2.2 Fire‐Resistant Fluids (HF)
			2.2.3 Synthetic Fluids (HS)
			2.2.4 Environmentally Friendly Fluids
			2.2.5 Water Hydraulics
			2.2.6 Comparisons Between Hydraulic Fluids
		2.3 Physical Properties of Hydraulic Fluids
		2.4 Fluid Compressibility: Bulk Modulus
		2.5 Fluid Density
		2.6 Fluid Viscosity
			2.6.1 Viscosity as a Function of Temperature
			2.6.2 Viscosity as a Function of Pressure
		2.7 Entrained Air, Gas Solubility, and Cavitation
			2.7.1 Entrained Air
			2.7.2 Gas Solubility
			2.7.3 Equivalent Properties of Liquid–Air Mixtures
		2.8 Contamination in Hydraulic Fluids
			2.8.1 Considerations on Hydraulic Filters
			2.8.2 Filter Placement
		2.9 Considerations on Hydraulic Reservoirs
			2.9.1 Tank Volume
			2.9.2 Basic Design of a Tank
		Problems
	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
			3.4.1 Application to a Hydraulic Cylinder
		3.5 Bernoulli's Equation
			3.5.1 Generalized Bernoulli's Equation
			3.5.2 Major Losses
			3.5.3 Minor Losses
		3.6 Hydraulic Resistance
		3.7 Stationary Modeling of Flow Networks
		3.8 Momentum Equation
			3.8.1 Flow Forces
		Problems
	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
			4.5.1 Orifices in Pressure and Return Lines
			4.5.2 Orifices in Pilot Lines
		Problems
	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
			5.3.1 Validity of the Lumped Parameter Approach
			5.3.2 Further Considerations on the Line Impedance Model
		5.4 Damping Effect of Hydraulic Accumulators
		Problems
References
Part II Hydraulic Components
	Objectives
	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
			6.7.1 Fluid Compressibility
			6.7.2 Internal and External Leakage
			6.7.3 Friction
			6.7.4 Other Types of Losses
		6.8 Volumetric and Hydromechanical Efficiency
			6.8.1 Trends for Volumetric and Hydromechanical Efficiencies
		6.9 Design Types
			6.9.1 Swashplate‐type Axial Piston Machines
			6.9.2 Bent Axis‐type Axial Piston Machines
			6.9.3 Radial Piston Machines
			6.9.4 Gear Machines
			6.9.5 Vane‐type Machines
		Problems
	Chapter 7 Hydraulic Cylinders
		7.1 Classification
		7.2 Cylinder Analysis
		7.3 Ideal vs. Real Cylinder
		7.4 Telescopic Cylinders
			7.4.1 Single Acting Telescopic Cylinder
			7.4.2 Double Acting Telescopic Cylinder
		Problems
	Chapter 8 Hydraulic Control Valves
		8.1 Spring Basics
		8.2 Check and Shuttle Valves
			8.2.1 Check Valve
			8.2.2 Pilot Operated Check Valve
			8.2.3 Shuttle Valve
		8.3 Pressure Control Valves
			8.3.1 Pressure Relief Valve
			8.3.2 Pressure‐reducing Valve
		8.4 Flow Control Valves
			8.4.1 Two‐way Flow Control Valve
			8.4.2 Fixed Displacement Pump Circuit with a Two‐way Flow Control Valve
			8.4.3 Three‐way Flow Control Valve
			8.4.4 Fixed Displacement Pump Circuit with a Three‐way Flow Control Valve
		8.5 Directional Control Valves
			8.5.1 Meter‐in and Meter‐out Configurations
			8.5.2 Neutral Position
		8.6 Servovalves
			8.6.1 Characteristic of Servovalves
			8.6.2 Servovalves vs. Proportional Valves
		Problems
	Chapter 9 Hydraulic Accumulators
		9.1 Accumulator Types
			9.1.1 Weight‐loaded Accumulators
			9.1.2 Spring‐loaded Accumulators
			9.1.3 Gas‐charged Accumulators
			9.1.4 Piston‐type Accumulators
			9.1.5 Diaphragm‐type Accumulators
			9.1.6 Bladder‐type Accumulators
		9.2 Operation of Gas‐charged Accumulators
		9.3 Typical Applications
			9.3.1 Energy Accumulation
			9.3.2 Emergency Supply
			9.3.3 Energy Recuperation
			9.3.4 Hydraulic Suspensions
			9.3.5 Pulsation Dampening: Shock Attenuation
		9.4 Equation and Sizing
			9.4.1 Accumulator as Energy Storage Device
			9.4.2 Accumulator as a Dampening Device
		Problems
References
Part III Actuator Control Concepts
	Objectives
	Chapter 10 Basics of Actuator Control
		10.1 Control Methods: Speed, Force, and Position Control
		10.2 Resistive and Overrunning Loads
			10.2.1 Power Flow Depending on the Load Conditions
		Problems
	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
	Chapter 12 Regeneration with Single Rod Actuators
		12.1 Basic Concept of Regeneration
		12.2 Actual Implementation
			12.2.1 Directional Control Valve with External Regeneration Valves
			12.2.2 Directional Control Valve with Regenerative Extension Position
			12.2.3 Solution with Automated Selection of the Regeneration Mode
		Problems
References
Part IV Metering Controls for a Single Actuator
	Objectives
	Chapter 13 Fundamentals of Metering Control
		13.1 Basic Meter‐in and Meter‐out Control Principles
			13.1.1 Meter‐in Control
			13.1.2 Meter‐out Control
			13.1.3 Remarks on the Meter‐in and the Meter‐out Controls
		13.2 Actual Metering Control Components
			13.2.1 Single Spool Proportional DCVs
			13.2.2 Independent Metering Control Elements
		13.3 Use of Anticavitation Valves for Unloaded Meter‐out
		Problems
	Chapter 14 Load Holding and Counterbalance Valves
		14.1 Load‐holding Valves
			14.1.1 Pilot Operated Check Valve
		14.2 Counterbalance Valves
			14.2.1 Basic Operating Principle
			14.2.2 CBV Architecture
			14.2.3 Detailed Operation of CBV
			14.2.4 Effect of the Pilot Ratio and of the Pressure Setting
			14.2.5 Counterbalance Valve with Vented Spring Chambers
		Problems
	Chapter 15 Bleed‐off and Open Center Systems
		15.1 Basic Bleed‐off and Open Center Circuits
		15.2 Bleed‐off Circuit Operation
			15.2.1 Energy Analysis
		15.3 Basic Open Center System
			15.3.1 Operation
			15.3.2 Open Center Valve Design
			15.3.3 Energy Analysis
		15.4 Advanced Open Center Control Architectures
			15.4.1 Negative Flow Control
			15.4.2 Positive Flow Control
			15.4.3 Energy Analysis for Advanced Open Center Architectures
		Problems
	Chapter 16 Load Sensing Systems
		16.1 Basic Load Sensing Control Concept
		16.2 Load Sensing System with Fixed Displacement Pump
			16.2.1 Basic Schematic
			16.2.2 Operation
			16.2.3 Energy Analysis
			16.2.4 Saturation Conditions
		16.3 Load Sensing Valve
		16.4 Load Sensing System with Variable Displacement Pump
			16.4.1 Basic Schematic
			16.4.2 Operation
			16.4.3 Energy Analysis
			16.4.4 Saturation Conditions
		16.5 Load Sensing Pump
		16.6 Load Sensing Solution with Independent Metering Valves
		16.7 Electronic Load Sensing (E‐LS)
		Problems
	Chapter 17 Constant Pressure Systems
		17.1 Constant Pressure System with Variable Displacement Pump
			17.1.1 Basic Schematic and Operation
			17.1.2 Energy Analysis
		17.2 Constant Pressure System with Unloader (CPU)
		17.3 Constant Pressure System with Fixed Displacement Pump
			17.3.1 Basic Schematic and Operation
		17.4 Application to Hydraulic Braking Circuits
		Problems
References
Part V Metering Controls for Multiple Actuators
	Objectives
	Chapter 18 Basics of Multiple Actuator Systems
		18.1 Actuators in Series and in Parallel
			18.1.1 Series Configuration
			18.1.2 Parallel Configuration
		18.2 Elimination of Load Interference in Parallel Actuators
			18.2.1 Solving Load Interference Using Compensators
			18.2.2 Solving Load Interference with a Volumetric Coupling
		18.3 Synchronization of Parallel Actuators Through Flow Dividers
			18.3.1 Spool‐type Flow Divider
			18.3.2 Spool‐type Flow Divider/Combiner
			18.3.3 Volumetric Flow Divider/Combiner
		Problems
	Chapter 19 Constant Pressure Systems for Multiple Actuators
		19.1 Basic Concepts for a Multi‐Actuator Constant Pressure System
			19.1.1 Basic Schematic
			19.1.2 Flow Saturation
			19.1.3 Energy Analysis
		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
			20.1.1 Operation
			20.1.2 Energy Analysis
			20.1.3 Flow Saturation
			20.1.4 Considerations On the Open Center Spool Design
			20.1.5 Load Interference in Open Center Systems
		20.2 Tandem and Series Open Center Systems
			20.2.1 Tandem Configuration
			20.2.2 Series Configuration
		20.3 Advanced Open Center Circuit for Multiple Actuators: The Case of Excavators
		Problems
	Chapter 21 Load Sensing Systems for Multiple Actuators
		21.1 Load Sensing Systems Without Pressure Compensation (LS)
			21.1.1 Basic Circuit
			21.1.2 Energy Analysis
			21.1.3 Valve Implementation and Extension to More Actuators
		21.2 Load Sensing Pressure Compensated Systems (LSPC)
			21.2.1 LSPC with Pre‐compensated Valve Technology
			21.2.2 LSPC with Post‐Compensated Valve Technology
		21.3 Flow Saturation and Flow Sharing in LS Systems
			21.3.1 Flow Saturation with Pre‐Compensated LSPC
			21.3.2 Flow Saturation with Post‐Compensated LSPC
		21.4 Pre‐ vs. Post‐compensated Comparison
			21.4.1 Pressure Saturation
			21.4.2 Flow Saturation
			21.4.3 Control Accuracy
		21.5 Independent Metering Systems with Load Sensing
		Problems
	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
			22.4.1 Hydrostatic Steering Unit Description
			22.4.2 Types of Hydrostatic Steering Units
		22.5 Priority Valves
			22.5.1 Priority Valve for a Fixed Displacement Flow Supply
			22.5.2 Priority Valve for Load Sensing Circuits
		Problems
References
Part VI Hydrostatic Transmissions and Hydrostatic Actuators
	Objectives
	Chapter 23 Basics and Classifications
		23.1 Hydrostatic Transmissions and Hydrostatic Actuators
			23.1.1 Basic Definitions
			23.1.2 Supply Concepts Used in Hydrostatic Transmissions and Hydrostatic Actuators
		23.2 Primary Units for Hydrostatic Transmissions and Hydrostatic Actuators
			23.2.1 Constant Speed Prime Mover and Variable Displacement Pump
			23.2.2 Variable Speed Prime Mover and Fixed Displacement Pump
			23.2.3 Variable Speed Prime Mover and Variable Displacement Pump
		23.3 Over‐center Variable Displacement Pump
		23.4 Typical Applications
		23.5 Classification Summary
	Chapter 24 Hydrostatic Transmissions
		24.1 Main Parameters for a Hydrostatic Transmission
		24.2 Theoretical Layouts
			24.2.1 Pump and Motor with Fixed Displacement (PFMF)
			24.2.2 Variable Displacement Pump and Fixed Displacement Motor (PVMF)
			24.2.3 Fixed Displacement Pump and Variable Displacement Motor (PFMV)
			24.2.4 Variable Displacement Pump and Variable Displacement Motor (PVMV)
			24.2.5 Variable Displacement Pump and Dual Displacement Motor (PVM2)
		24.3 Open Circuit Hydrostatic Transmissions
			24.3.1 Open Circuit HT with Flow Supply: Basic Circuit
			24.3.2 Open Circuit HT with Flow Supply: Common Implementation
		24.4 Closed Circuit Hydrostatic Transmissions
			24.4.1 Charge Circuit and Filtration
			24.4.2 Cross‐port Pressure Relief Valves
			24.4.3 Flushing Circuit
		24.5 Closed Circuit Displacement Regulators
			24.5.1 Electrohydraulic Displacement Regulator for Closed Circuit Pumps
			24.5.2 Automotive Control for Closed Circuit Pumps
			24.5.3 Electrohydraulic Displacement Regulator for Motors
			24.5.4 Automatic Pressure Regulator for Motors
		Problems
	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
			25.3.1 Planetary Gear Train
			25.3.2 Hydromechanical Power‐split Transmission
		25.4 Hybrid Transmissions
			25.4.1 Series Hybrids
			25.4.2 Parallel Hybrids
			25.4.3 Series‐parallel Hybrids (or Power‐split Hybrids)
		25.5 Sizing Hydrostatic Transmissions for Propel Applications
			25.5.1 Step 1: Maximum Tractive Effort Calculation
			25.5.2 Step 2: Fixed or Variable Displacement Motor Selection
			25.5.3 Step 3: Sizing of the Motor (Secondary Unit)
			25.5.4 Step 4: Sizing of the Pump (Primary Unit)
			25.5.5 Step 5: Check Results
		Problems
	Chapter 26 Hydrostatic Actuators
		26.1 Open Circuit Hydrostatic Actuators
		26.2 Closed Circuit Hydrostatic Actuators
			26.2.1 Cylinder Extension
				26.2.1.1 Extension in Pumping Mode (F > F*)
				26.2.1.2 Extension in Motoring Mode (F < F*)
			26.2.2 Cylinder Retraction
				26.2.2.1 Retraction in Motoring Mode (F > F*)
				26.2.2.2 Retraction in Pumping Mode (F < F*)
		26.3 Further Considerations on the Charge Pump and the Accumulator
		26.4 Final Remarks on Hydrostatic Actuators
	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
Appendix A Prime Movers and Their Interaction with the Hydraulic Circuit
	A.1 Corner Power Method and its Limitations
	A.2 Diesel Engine and its Interaction with a Hydraulic Pump
		A.2.1 Diesel Engine Regulation
		A.2.2 Engine Stall
		A.2.3 Overrunning Loads
		A.2.4 Fuel Consumption
	A.3 Electric Prime Movers
		A.3.1 Brushed DC Electric Motors
			A.3.1.1 DC Hydraulic Power Units
		A.3.2 Induction Motor (or Asynchronous Motor)
		A.3.3 Synchronous Motor
	A.4 Power Limitation in Hydraulic Pumps
		A.4.1 Torque Limiting Using Fixed Displacement Pumps
		A.4.2 Torque Limiting Using Variable Displacement Pumps
References
Index
EULA