Table of contents
1 Introduction 1
1.1 Development trend of machinery manufacturing industry 1
1.2 Application of machining center 2
1.3 Application and development trend of pneumatic technology 2
2 Parts analysis of 5WB left crankcase 4
2.1 Function and structural characteristics of 5WB left crankcase 4
2.1. 1 Function of 5WB left crankcase 4
2.2.2 Structural characteristics of 5WB left crankcase 4 2.2
Manufacturability analysis of 5WB left crankcase 4
3 Process specification design of 5WB left crankcase 6
3.1 Production program and production type Determination 6
3.2 Selection of blank 6
3.3 Selection of datum 6
3.3.1 Concept and classification
of datum 7 3.3.2 Selection of positioning datum 7
3.4 Formulate process route 8
3.5 Determine machining allowance, process size and blank size 13
3.6 Determine cutting Amount and Basic Working Hours 20
4 Fixture Design 27
4.1 Fixture Design for Large Surface Milling and Boring Locating Pin Hole 28
4.1.1 Selection of Positioning Datum 28
4.1.2 Calculation of Cutting Force and Analysis of Clamping Force 28
4.1.3 Clamping Components and Determination of power unit 29
4.1.4 Analysis of positioning error 31
4.1.5 Brief description of fixture design and operation 31
4.2 Design of fixture for milling joint surface 31
4.2.1 Selection of positioning datum 31
4.2.2 Calculation of Cutting Force and Analysis of Clamping Force 31
4.2.3 Determination of Clamping Components and Power Device 32
4.2.4 Analysis of Positioning Error 32
4.2.5 Brief Description of Fixture Design and Operation 33 Conclusion
34
Acknowledgments 35
References 36
2 Parts analysis of 5WB left crankcase
2.1 Function and structural characteristics of 5WB left crankcase
2.1.1 Function of 5WB left
crankcase The crankcase assembles the shafts, sleeves, gears and other related parts of the machine or components into a whole, so that they maintain the correct mutual position, and coordinate the transmission of motion or power according to a certain transmission relationship [3]. Therefore, the processing quality of the box will directly affect the assembly accuracy, performance index and service life of the engine.
2.2.2 Structural features of 5WB left crankcase
The parts structure of 5WB left crankcase is shown in Figure 2.1.
图2.1 零件结构图
For the specific structure of the parts of the 5WB left crankcase, see the appendix "Parts Diagram of the 5WB Left Crankcase".
From the parts diagram, we can see that the structural characteristics of the box are: complex shape, thin and uneven wall, cavity inside, many processing parts, and difficult processing. There are not only holes and planes with high precision requirements, but also many precision General fastening holes are required. Therefore, the machining labor of general box parts accounts for about 15%-20% of the entire product processing.
