Optimization Of Clamping Mechanism Of Heavy-duty Turning Tool And Analysis Of Fastening Screw Pre-tightening Force

The heavy-duty turning tool is an important tool for processing large parts,and an appropriate heavy-duty turning tool clamping mechanism can effectively improve the force of the blade and the blade supporting surface.In the clamping mechanism,the pre-tightening force of the fastening screw will directly affect the clamping force of the blade,and the change of the clamping force will directly affect the stress field distribution of the blade and the blade support surface.At present,there are many researches on the clamping mechanism of heavy-duty turning tools at home and abroad,but there are few researches on the blade fastening screw,and most manufacturers rely on the experience of workers to pre-tighten the fastening screws,and there are no specific regulations.Therefore,in order to reduce the maximum stress value of the blade,improve the stress field distribution of the blade support surface,improve the working efficiency of the tool,and ensure the machining accuracy,it is necessary to study the clamping mechanism and pre-tightening force of the heavy turning tool.This paper analyzes the structure and force of the commonly used heavy-duty turning tool blade clamping mechanism are analyzed,based on the advantages and disadvantages of different clamping mechanisms,a new type of heavy-duty turning tool clamping mechanism is proposed,namely the taper hole ball head lever type heavy-duty turning tool clamping mechanism.And obtains the influence of geometric parameters of main components in clamping mechanism on the maximum stress value of blade and the stress field uniformly of blade support surface.First of all,based on the Hertz contact formula and lever balance equation,the calculation formula of the stress at the dangerous point of the insert without cutting force is derived,and the formula of the clamping force on the blade,which provides a theoretical basis for the analysis of the blade force.Then,according to the calculation formula of the stress at the dangerous point of the blade,the parameters that have great influence on the stress of the blade are determined.Finally,combined with model assembly and theoretical calculation,the influence of these parameters on the blade stress is analyzed,and the optimal value range is determined.Then,the three-dimensional model and the finite element model of the heavy-duty turning tool are established,and the parameters related to the force of the blade and the blade support surface were carried out by single factor simulation test and orthogonal test using ANSYS Workbench.The stress of the blade is determined when different parameter combinations are used,and a group of parameter combinations that can make the blade stress achieve the optimal condition are obtained.Finally,the simulation test analysis of the fastening screw in the clamping mechanism is carried out,the force of the blade and the force of the screw with different main parameters of the fastening screw are obtained,and the optimal parameter combination is obtained.The best preload range was determined by observing the force of blade and screw under different preloads.