Tài liệu Bộ sách đào tạo kỹ thuật truyền động thủy lực DIDATIC của hãng FESTO (Đức)

Table of contents

1 Tasks of a hydraulic installation __________________________________ 7

1.1 Stationary hydraulics____________________________________________ 8

1.2 Mobile hydraulics _____________________________________________ 10

1.3 Comparison of hydraulics with other control media __________________ 11

2 Fundamental physical principles of hydraulics _____________________ 13

2.1 Pressure _____________________________________________________ 13

2.2 Pressure transmission__________________________________________ 18

2.3 Power transmission ____________________________________________ 19

2.4 Displacement transmission _____________________________________ 21

2.5 Pressure transfer ______________________________________________ 23

2.6 Flow rate_____________________________________________________ 25

2.7 Continuity equation____________________________________________ 26

2.8 Pressure measurement _________________________________________ 30

2.9 Temperature measurement______________________________________ 31

2.10 Measurement of flow rate _______________________________________ 31

2.11 Types of flow _________________________________________________ 31

2.12 Friction, heat, pressure drop ____________________________________ 35

2.13 Energy and power _____________________________________________ 41

2.14 Cavitation____________________________________________________ 51

2.15 Throttle points ________________________________________________ 53

3 Hydraulic fluid________________________________________________ 57

3.1 Tasks for hydraulic fluids _______________________________________ 57

3.2 Types of hydraulic fluid _________________________________________ 58

3.3 Characteristics and requirements_________________________________ 59

3.4 Viscosity _____________________________________________________ 60

4 Components of a hydraulic system _______________________________ 67

4.1 Power supply section __________________________________________ 67

4.2 Hydraulic fluid ________________________________________________ 67

4.3 Valves_______________________________________________________ 68

4.4 Cylinders (linear actuators)______________________________________ 70

4.5 Motors (rotary actuators) _______________________________________ 71

5 Graphic and circuit symbols_____________________________________ 73

5.1 Pumps and motors_____________________________________________ 73

5.2 Directional control valves _______________________________________ 74

5.3 Methods of actuation __________________________________________ 75

5.4 Pressure valves _______________________________________________ 76

5.5 Flow control valves ____________________________________________ 78

5.6 Non-return valves _____________________________________________ 79

5.7 Cylinders ____________________________________________________ 80

5.8 Transfer of energy and conditioning of the pressure medium __________ 82

5.9 Measuring devices_____________________________________________ 83

5.10 Combination of devices_________________________________________ 83

6 Design and representation of a hydraulic system ___________________ 85

6.1 Signal control section __________________________________________ 86

6.2 Hydraulic power section ________________________________________ 87

6.3 Positional sketch ______________________________________________ 90

6.4 Circuit diagram________________________________________________ 91

6.5 Components plus technical data__________________________________ 92

6.6 Function diagram______________________________________________ 94

6.7 Function chart ________________________________________________ 95

7 Components of the power supply section __________________________ 97

7.1 Drive________________________________________________________ 97

7.2 Pump _______________________________________________________ 99

7.3 Coupling ____________________________________________________ 107

7.4 Reservoir ___________________________________________________ 107

7.5 Filters ______________________________________________________ 109

7.6 Coolers _____________________________________________________ 120

7.7 Heaters_____________________________________________________ 122

8 Valves______________________________________________________ 123

8.1 Nominal sizes________________________________________________ 123

8.2 Design _____________________________________________________ 125

8.3 Poppet valves________________________________________________ 126

8.4 Spool valves_________________________________________________ 127

8.5 Piston overlap _______________________________________________ 129

8.6 Control edges________________________________________________ 134

9 Pressure valves ______________________________________________ 137

9.1 Pressure relief valves _________________________________________ 137

9.2 Pressure regulators ___________________________________________ 144

10 Directional control valves______________________________________ 149

10.1 2/2-way valve _______________________________________________ 153

10.2 3/2-way valve _______________________________________________ 157

10.3 4/2-way valve _______________________________________________ 159

10.4 4/3-way valve _______________________________________________ 162

11 Non-return valves ____________________________________________ 167

11.1 Non-return valve _____________________________________________ 168

11.2 Piloted non-return valve _______________________________________ 172

11.3 Piloted double non-return valve _________________________________ 175

12 Flow control valves ___________________________________________ 179

12.1 Restrictors and orifice valves ___________________________________ 180

12.2 One-way flow control valve _____________________________________ 184

12.3 Two-way flow control valve_____________________________________ 185

13 Hydraulic cylinders___________________________________________ 193

13.1 Single-acting cylinder _________________________________________ 194

13.2 Double-acting cylinder ________________________________________ 196

13.3 End position cushioning _______________________________________ 199

13.4 Seals_______________________________________________________ 200

13.5 Types of mounting____________________________________________ 202

13.6 Venting _____________________________________________________ 202

13.7 Characteristics _______________________________________________ 203

13.8 Buckling resistance ___________________________________________ 205

13.9 Selecting a cylinder ___________________________________________ 207

14 Hydraulic motors_____________________________________________ 211

15 Accessories _________________________________________________ 215

15.1 Flexible hoses _______________________________________________ 217

15.2 Pipelines____________________________________________________ 223

15.3 Sub-bases __________________________________________________ 226

15.4 Bleed valves_________________________________________________ 228

15.5 Pressure gauges _____________________________________________ 229

15.6 Pressure sensors _____________________________________________ 230

15.7 Flow measuring instruments____________________________________ 231

16 Appendix ___________________________________________________ 233