1. 1 About truck cranes

Engineering crane is an important lifting equipment widely used in various engineering construction, and it is a mechanical equipment used for lifting, transporting, loading and unloading or installing materials. It is widely used as the main construction machinery for industrial and civil buildings. It plays a very important role in reducing labor intensity, saving manpower, reducing construction cost, improving construction quality, accelerating construction speed and realizing engineering construction mechanization. At present, China is one of the countries that use construction cranes the most in the world.

In recent years, with the expansion of engineering construction scale, the workload of lifting and installation is increasing, and the higher requirements for lifting capacity, working radius and maneuverability promote the rapid development of cranes. Tower cranes and truck cranes with advanced level have become the main force of mechanized construction.

Compared with other cranes, truck cranes not only have the advantages of convenient movement, flexible operation and easy hoisting in different positions, but also the hydraulic system used to drive and control them is easy to realize improved design. With the continuous development of hydraulic transmission technology, truck crane has become the main development goal of crane manufacturers.

Advantages and disadvantages of 1.2 hydraulic transmission applied to truck cranes.

Advantages of 1.2. 1

1. Advantages of crane structure and technical performance:

The power from the automobile engine is transferred to the working mechanism through the oil pump, and in this process, a larger transmission ratio can be obtained, which saves the complicated and bulky transmission device needed for mechanical transmission. It not only makes the structure compact, but also greatly reduces the weight of the whole machine and improves the lifting performance of the whole machine. At the same time, it is convenient to transform rotary motion into translational motion, and it is easy to realize the luffing and automatic expansion and contraction of the crane. The mechanisms are connected by pipelines, which can obtain compact and reasonable speed and improve the technical characteristics of the engine. It is convenient to realize automatic operation and improve the labor intensity and conditions of drivers. Because the parts can be controlled by micro-motion, the operation is relatively stable, thus improving the installation accuracy and operation quality of the crane.

Adopting hydraulic transmission, there is no severe dry friction pair in the main mechanism, which reduces the lubricating parts, thus reducing the maintenance and technical preparation time.

2. Economic advantages

..... Table of Contents: Summary 1

Abstract 2

Chapter 1 Overview 1

1. 1 About truck cranes 1

Advantages and disadvantages of 1.2 hydraulic transmission applied to truck crane 1

1.2. 1 advantages 1

1.2.2 Disadvantage 2

1.3 Class II hydraulic system

1.4 Function, composition and working characteristics of hydraulic system of truck crane Ⅱ

1.5 application status and development trend of hydraulic system of truck crane 4

1.6 Source of this topic, task requirements and performance parameters of the whole machine 5

1.7 Main research work of this topic 7

Chapter II Selection of Hydraulic System Components 8

2. 1 Typical working condition analysis and system requirements 8

2. 1. 1 Operation of telescopic mechanism 8

2. 1.2 Operation of auxiliary arm 8

2. 1.3 Joint operation of three or more institutions 8

2. 1.4 Determination of typical working conditions 8

2. 1.5 system requirements 9

2.2 hydraulic system selection 10

2.2. 1 analysis of hydraulic system of this machine 10

2.2.2 Power combination, distribution and control of various institutions 1 1

2.3 Selection of various actuators 12

Chapter 3 Composition Principle and Performance Analysis of Hydraulic Circuits 14

3. 1 primary and secondary winding circuit 14

3. 1. 1 performance requirements 14

3. 1.2 main components 15

3. 1.3 main circuit 15

3. 1.4 function realization and working principle 15

3.2 slewing circuit 17

3.2. 1 performance requirements

Main components 18

Main circuit 18

3.2.4 Function realization and working principle 18

3.3 Telescopic circuit 19

3.3. 1 performance requirements

Main components 19

The main circuit 20

3.3.4 Function Realization and Working Principle 20

3.4 pitch loop 2 1

3.4. 1 performance requirements

Main component 2 1

The main circuit 22

3.4.4 Function Realization and Working Principle 22

3.5 Branch Circuit 23

Performance requirements 23

Main component 23

Main circuit 23

3.5.4 Function realization and working principle

The fourth chapter design and calculation of hydraulic system on page 25.

4. 1 Working parameters of hydraulic system and main parameters of each mechanism 25

4. 1. 1 main parameters of working mechanism 25

4. 1.2 hydraulic system parameters 26

4.2 Selection and calculation of hydraulic components 27

4.2. 1 Selection and calculation of hydraulic motors and pumps 27

4.2.2 Selection of Hydraulic Valve

4.2.3 Selection of Hydraulic Auxiliary Components 40

Chapter 5 Performance calculation of each loop of the system 44

5. 1 Power calculation of each loop of the system 44

5. 1. 1 power selection for each loop 44

5. 1.2 Calculation of volumetric efficiency and pressure efficiency of pipeline system 44

5.2 Check calculation of performance of each loop of the system 45

5.2. 1 lifting circuit 45

5.2.2 Swing circuit 50

5.2.3 expansion circuit 5 1

5.2.4 Pitch loop 53

5.2.5 Branch Circuit 54

5.3 Heating calculation of hydraulic system 55

5.3. 1 duty cycle T55

5.3.2 Heat energy generated by oil pump loss H56

5.3.4 Heat generated by motor 57

5.3.5 Fuel tank heat dissipation 58

Chapter VI Special Study on Electro-hydraulic Proportional Control of Crane Hydraulic System 59 pages

6. 1 Principle and characteristics of electro-hydraulic proportional control 59

6.2 Electro-hydraulic proportional control of crane components 60

6.3 Electro-hydraulic proportional control of each loop 63

6.4 Influence of electro-hydraulic ratio on crane hydraulic system and its development trend 66

Chapter VII Summary 68

7. 1 design summary 68

7.2 Work Outlook 68

Acknowledgement 69

Reference 70

Appendix 1 QY40 Schematic Diagram of Hydraulic System of Hydraulic Truck Crane 7 1

Appendix 2 Operation Sequence Table of QY40 Electromagnet in Hydraulic System of Hydraulic Truck Crane 72

Appendix 3 QY40 Hydraulic System Parts List of Hydraulic Truck Crane 73

Task manual 74

Literature review 76

Opening report 87

Translation 90 references:

[1] Write group compilation? Crane design manual? 【S】？ Machinery Industry Press? 1980

[2] edited by Liu Xinde? Pocket hydraulic design manual? 【S】？ Machinery Industry Press? 2004

[3] Shanghai Coal Mining Machinery Research Institute? Hydraulic transmission design manual? 【S】？ Shanghai People's Publishing House 1976

[4] Written by the German company Manlesman? Manual of Hydraulic Components of Man Lehsmann Company? [S]

[5] Zhu Caixin editor? Hydraulic transmission and control? [M]？ Chongqing University Press? 1998

[6] Xu Fuling and Chen Yaoming? Hydraulic pneumatic transmission? [M]？ Machinery Industry Press? 200 1

[7] Zhou Shichang editor? Hydraulic system design atlas? [M]？ Machinery Industry Press? 2003

[8] Yang Guoping and Liu Zhong? Modern construction machinery hydraulic and hydraulic practical technology? [M]？ People's Communications Press

[9] Zhao Xianxin? Principle and maintenance of hydraulic transmission device of construction machinery? [M]？ Liaoning science and technology publishing house

[10] edited by Lei Tianjue? Handbook of hydraulic engineering? 【S】？ Machinery Industry Press? 1990 Introduction: The design of hydraulic system of QY40 truck crane is the most critical step in the design process of this crane. According to the technical index of the hydraulic system, the overall scheme of the system is designed, the function and working principle of the system are analyzed, the basic structure and main components of each loop of the system are preliminarily determined, and the selection of components is calculated according to the given mechanical performance parameters and hydraulic performance parameters, and the requirements of the crane are met through system performance checking and heating.

In this paper, the principle, control elements, loop control, control measures and its influence on truck crane, an advanced technology currently adopted by truck crane, are also specially studied. Therefore, the application of electro-hydraulic proportional control technology in truck crane has been fully affirmed, and the development prospect of truck crane is full of hope.