Research In Key Technology Of Shrink Fitting Process For A Large Crankshaft

In the "11th five-year plan" period, our shipbuilding industry has a rapiddevelopment. The shipbuilding completion is65.6million deadweight tons in2010. Inscientific and technological innovation of ship type, high technology ship and oceanengineering equipment, breakthroughs were made. Local mating ability for majormarine equipment promotes quickly. The shipbuilding cycle shortened obviously, andthe economic operation quality improved significantly. For tens to hundreds ofthousands of tons of ship Marine diesel engine at low speed, used to convey large torqueof the crankshaft is an extremely important part. The half built-up crankshaft has overallquality, special material requirements, hot and cool process multi-channel, highmachining accuracy. It has great difficulty and manufacturing requirement.Shrink fitting, as a key process, greatly impact the quality of the crankshaft. Inactual processing technology, it is found that there are many problems to meet thedesign requirements and limitations. On the basis of the common used electromagneticinduction heating, these papers solved these problems, and improved the speed andquality of crankshaft shrink fitting process. What’s more, labor conditions are improved.The paper studied the relationship between temperature field change and thecrankshaft stress and deformation in the shrink fitting process. Through numericalsimulation, the factors affecting the quality of the crankshaft were analyzed. Based onANSYS, we searched for quality control strategy in the crankshaft shrink fitting process,and finally experimented research work on sample. So we improved the quality,shortened the process time, and provided a reference for the establishment of crankshaftred shrink fitting process. At the same time, through calculation and analysis of onemodel, then transit to the analysis of other models, gradually establish and perfect theexpert knowledge base of the crankshaft for finite element analysis and research. Finallyrealizes the parametric design of shrink fitting, to provide convenience for theengineering design. This thesis topic came from Shanghai electric Marine crankshaft research projects.Through the combination of theory, numerical simulation and experiment methods, thefollowing contents are studied:1. The mechanism and advantages of electromagnetic induction heating. From theprinciple of electromagnetic induction heating and the perspective of energy transfer, weexplore the mechanism of the electromagnetic induction, fluency parameters in theheating process, the energy loss and the advantages of induction heating. According tothe need of experimental study, the choice of induction heating power is analyzed.2. Electromagnetic field and thermal field numerical simulation of electromagneticinduction heating was studied for the crankshaft. In order to master the mechanism ofthe electromagnetic induction heating, crankshaft model and the correspondingnumerical analysis model were established. With finite element method (FEM)numerical calculation, electromagnetic field distribution and the distribution oftemperature field were achieved.3. The major parameters that affect the heating current density are currentfrequency and heating time. By calculating different parameters composition, fluency ofvarious parameters on the crankshaft was analyzed. According to the analysis results,select the appropriate data combination to get the temperature distribution, then theuniformity of temperature distribution was analyzed.4. Crank expansion deformation in the process of induction heating and contractiondeformation in the cooling process. Research to improve the shrink fitting holedeformation caused by geometry asymmetry of the structure. It is impossible toeliminate the adverse effects in theory. Master the irregular deformation rule, then putforward a series of optimization design.5. On the basis of summarizing the previous research results, the next phase ofwork and the key problems were raised.