Design And Development Of Blade Root Pin-hole Machining Device For Last Stage Blade Of Large Industrial Steam Turbine

Industrial steam turbines are widely used in various industrial enterprises.As the diameter of industrial steam turbine rotors increases,the diameter and depth of the blade root pin holes used to connect the blades to the rotor have also increased accordingly.Traditional blade root pin hole machining devices can no longer meet the production demand.Aiming at the machining of the blade root pin hole of the last stage blade of large industrial steam turbine,this paper studies the problems of the blade root pin hole machining device that insufficient machining space,small spindle torque and low degree of electrification.The worm gear mechanism is used to realize the automatic feed function of power unit,and increase power unit axial force,manual feed mode and automatic feed mode can be switched at any time by operating the handle;power unit stroke control is realized through grating ruler and digital display function,and positioning accuracy and repeatability are improved at the same time.The first chapter introduces the current status of industrial steam turbines and blade root pin hole processing,analyzes the research status of blade root pin hole processing technology and blade root pin hole machining device at domestic and foreign,and points out the problems of blade root pin hole processing.The research content of this article and the problems to be solved are put forward.The second chapter introduces the machining target of blade root pin hole,expounds the functions and processing requirements that need to be met by the blade root pin hole machining device,and then proposes the overall design plan of the machining device,including the power unit,supporting device,clamping device and cooling device,introduced their structure,working principle and overall layout,and put forward the design method of main parameters of machining device on this basis.The third chapter conducts in-depth research on the main shaft components,transmission mechanism,automatic feed mechanism and sliding seat in the power unit,expounds and puts forward the design principles and calculation methods of the main shaft structure,transmission chain and automatic feed mechanism,and proposed the selection method of spindle motor and automatic feed motor,and then proposed the calculation method and selection basis of X-axis sliding guide rail and Z-axis linear guide;finally,the design scheme of the indexing head of the tailstock and its clamping device is proposed.The fourth chapter studies the overall control plan of the blade root pin hole machining device,proposes design methods for the power supply system and control system,uses PLC,frequency converter,etc.to realize the electrification control of the machining device,and proposes the basis for the selection of main electrical equipment according to actual needs.The fifth chapter designs and develops a prototype based on the design method and selection basis proposed in this paper,debugs the prototype,verifies it through experiments,and puts it into practical application to verify its application value.The sixth chapter summarizes the work of this paper,summarizes the difficulties and innovations of the paper,analyzes the deficiencies of the blade root pin hole machining device,and proposes improvement ideas based on the results of the prototype application.