The Simulation Analysis And Drive Design Of Globoidal Cam Mechanism In NC Rotary Table

With the development of the society and the progress of science and technology, the application and popularization of NC machine tools is becoming more and more widely, the NC rotary table is one of the core features of NC machine tool, the performance of rotary table had a greater influence on the machining accuracy of NC machine tools, the transmission system of the NC rotary table has the overloading, high speed, high efficiency, good dynamic performance has become the research hot spot.At the same tim,the globoidal cam mechanism because of its high bearing capacity and high transmission precision has been widely used, it is important to improve and enhance the transmission characteristics of the turntable practical research significance by applies a globoidal cam mechanism in NC rotary table drive.Based on NC rotary table as the research object, this paper aimed at makino T2 type horizontal machining center, globoidal cam mechanism was applied to the type of NC rotary table drive design.First we determine the main dimensions of globoidal cam structure and finish the three-dimensional entity model in UG modeling, and import the static analysis and modal analysis based on the finite element software,the globoidal cam mechanism of electromechanical coupling dynamic characteristics are studied, the main research content and the work is as follows:In determining main structure size characteristics, according to the method of tensor rotation changes, the working curve of globoidal cam contour surface vector equation, spatial meshing equation, pressure Angle and contact stress are derived, according to the actual working parameter of NC rotary table, its transmission scheme and motor selection calculation process was given, at the same time, the design pressure Angle and the contact stress is derived as constraint conditions to determine the main structure of globoidal cam size, combining with the pressure Angle formula, we are discuss and analyzes the effects of structure size parameters on the pressure Angle and points out the methods of reducing pressure Angle.Based on work contour surface vector equation and spatial meshing equation, we use three-dimensional modeling software UG to finish entity modeling, at the same time for comparison, respectively gives the cylindrical roller and tapered roller surface of three-dimensional entity model, through to the two types of roller globoidal cam motion simulation analysis verified the correctness of the established model.Using ANSYS Workbench, two types of roller globoidal cam finite element analysis are studied, including surface deformation, strain and stress characteristics analysis in same static load,the result show that the location of the strain and stress are matrix with the rotating disc globoidal cam roller contact point, the situation conforms to the actual working condition and verify correctness of the globoidal cam static analysis of assembly constraint load.Comparing two types of surface static characteristics, the results show that the maximum stress value of the tapered roller globoidal cam surface is 399.21 MPa, less than the maximum stress value of cylindrical roller globoidal cam surface 425.14 MPa, the statics characteristic of apered roller globoidal cam is better than cylindrical roller globoidal cam, its carrying capacity is stronger, at the same time in order to avoid too much stress and strain of the formed by the resonance disable structure movement and malfunction, we gives the corresponding natural frequency and vibration mode by modal analysis of globoidal cam.Adopt the method of joint simulation in ADAMS and Matlab/Simulink software to study the electromechanical coupling dynamic characteristics of globoidal cam,the result of surface angular velocity and angular acceleration and contact stress analysis shows that the simulation curve surface of globoidal cam can be determined to meet the requirements of the continuous drive NC rotary table, and rotating disc movement rule meet the control requirements,the design of globoidal cam is feasible,comparing the curve of the contrast before and after the PI control, the results shows that the surface stress distribution and transmission stability by PI control are improved.