Chapter 1: Introduction ......................................... 1
1 Preface ...................................................... 1
2 Definitions for design and system design ..................... 2
3 Regulations .................................................. 3
4 Calculations ................................................. 3
5 Systems of Units ............................................. 4
6 Formulae and hydraulic symbols ............................... 5
Chapter 2: Parameters and properties of the fluids .............. 9
1 Properties
Density ...................................................... 9
Specific weight ............................................. 10
Specific gravity ............................................ 10
Viscosity ................................................... 11
Compressibility of fluids ................................... 13
Reynolds number and types of flow ........................... 14
2 Parameters
Pressure .................................................... 15
Flow and flow rate .......................................... 16
Fluid velocity .............................................. 18
Work and Power .............................................. 19
Drag and pressure loss ...................................... 20
Hydraulic shock ............................................. 22
Cavitation .................................................. 22
The Bernoulli Equation ...................................... 23
The Torricelli Equation ..................................... 24
Chapter 3: Hydraulic system components ......................... 27
1 Flow Restrictors ............................................ 27
2 Pressure Relief Valves ...................................... 30
3 Check Valves ................................................ 31
4 Reduction Valves ............................................ 32
5 Flow Controls ............................................... 33
6 Directional Control Valves .................................. 35
7 Hydraulic Pumps ............................................. 39
8 Hydraulic Motors ............................................ 45
9 Hydraulic Cylinders ......................................... 46
10 Pressure Switch ............................................. 50
11 Accumulators ................................................ 50
12 Hydraulic Filters ........................................... 53
13 Hydraulic Reservoirs ........................................ 57
14 Hydraulic Connectors ........................................ 62
15 Hydraulic Fluid ............................................. 63
16 Fluid Cleanliness ........................................... 68
17 Electric Motors ............................................. 70
Chapter 4: Management and quality of hydraulic system design
process ........................................................ 73
Brief history of quality ....................................... 73
Introduction ................................................... 75
Factors ........................................................ 76
Structuring the design process ................................. 77
Definitions of tools used ...................................... 79
Description of the design process steps ........................ 80
Design guideline ............................................... 85
Documenting the design activities .............................. 86
Project close-out criteria ..................................... 87
Failure Rate ................................................... 87
Patents ........................................................ 89
Legal aspect of the design process ............................. 90
Chapter 5: Hydraulic systems for high lift trucks .............. 93
Design principles .............................................. 94
Design requirements ............................................ 95
System with proportional manual directional valve .............. 97
System with electrically controlled proportional valves ....... 112
Hydraulic system with emergency lowering ...................... 115
Energy recovery system ........................................ 117
Hydraulic steering system ..................................... 120
Electro-Hydraulic steering system ............................. 126
Integrated hydraulic system ................................... 128
Jerky motion during lifting ................................... 129
Chapter 6: Hydraulic systems for low lift trucks .............. 135
Hydraulic system with two independent circuits ................ 135
Integrated system with priority load sensing valve ............ 137
Integrated system with accumulator ............................ 141
Chapter 7: Hydraulic systems for boom-type trucks ............. 145
Hydraulic circuit for boom manipulation ....................... 146
Hydraulic circuit for boom lifting ............................ 148
Hydraulic circuit with automatic shut-off valve ............... 146
Chapter 8: Selected topics .................................... 153
I Servicing the hydraulic systems ........................... 153
Troubleshooting principles
System Life
Servicing the fluid
Servicing filters
Servicing reservoirs
Servicing hydraulic pumps and motors
Servicing hydraulic cylinders
Servicing the valves
II Common problems ........................................... 158
Leaks
Overheating Slow lift
III Contamination of the hydraulic fluid ...................... 159
IV The future of the hydraulics .............................. 163
Appendixes
Appendix A ITA classification
Appendix В Physical properties of common fluids
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