Research On Turning Technology Of Main Shaft Of Super Large Turbine

The main shaft(or shafting)of the Francis turbine is the most critical part connecting the runner and the generator and transferring the mechanical energy of the turbine.I Medium and large hydraulic turbine shaft manufacturing technology is relatively mature,in the existing equipment,clamping and processing conditions,the shaft can obtain higher product quality.With the continuous progress of society,super large shaft(such as weight more than 120 t,shaft diameter more than 3000 mm,etc.)has gradually emerged,but its processing requirements have brought great challenges to the current manufacturers,especially the difficulty of turning processing,super large shaft due to the large size,more than the existing equipment clamping capacity,the existing tool flange scheme also has the problem of insufficient rigidity which leads to the machining quality not meeting the requirements and so on.This topic will be the super large turbine shaft as the research object,explore a use of existing equipment capacity to solve the super large turbine shaft turning process is extremely difficult or even impossible to achieve the technology.A "piercing" tool shaft is used to assemble and fix the super large shaft,and the scheme discussion,design,implementation and optimization are analyzed,including the comparison of mandrel truss structure and cylinder stiffening structure,mandrel and shaft fastening design scheme,mandrel and shaft assembly and disassembly process,shaft system scheme implementation and optimization.It is found that after the mandrel and shaft are assembled and fixed,there will be gaps in the assembly position,and keeping the whole shaft assembly system rigid enough is the key to the success or failure of the whole problem.Finally,the technical scheme is proved to be feasible after the implementation of various key measures.At present,the technical scheme has completed the turning processing of 16 super-large shafts of a large hydropower station,and the operation index of the power station is excellent after installation,reaching the requirements of highquality indicators Analysis of turning process of hydraulic turbine shaft.The structure,classification and characteristics of hydraulic turbine shaft are briefly introduced.Based on many years of experience in workshop shaft manufacturing,this paper analyzes and summarizes the datum transformation,manufacturing process and typical quality problems in the turning process of the Francis turbine shaft,and puts forward the key problems to be solved in the turning process of the super large shaft: insufficient equipment clamping capacity and weak rigidity of the shaft system.The clamping technology is unprecedented,which is a bold attempt and innovation on the basis of the existing "double tool flange" technical solution of large shaft.Finally,the technical scheme perfectly solves the problems of the super large shaft that can not be clamped and the shaft system is not rigid enough,and opens up a novel and low-cost technical route for the turning of the super large shaft.Especially for the existing domestic traditional large enterprises,their equipment service life is long,there is a certain gap between the processing capacity and the existing market demand.And this technical solution can help the traditional enterprises to achieve the current process which can not complete the manufacturing problem,in the future market competition,to take the lead to meet customer demand,and the first to win the market opportunity...