| The machine tool industry is the basis of mechanical manufacturing, and its levels decide the development of the manufacturing industry. As its speed, precision and efficiency improving, it need better static and dynamic characteristics. In addition to structure influence of the machine tool, its static and dynamic characteristics are closely related to machining precision, and affected by characteristics of the joint surface located at key parts. Domestic and foreign research shows that static stiffness of the machine tool by 30% ~ 50% depends on stiffness characteristics of joint surfaces that more than 60% of vibration problem derives from. Therefore, when doing research on dynamic characteristics, we must consider effects of joint surfaces.In the paper, based on theoretical analysis, finite element method and experimental verification, the study on dynamic characteristics of the fixed and moving surfaces that belong to Machine Tool BB5050 were comprehensively conducted. Then, according to the analysis results, the structure optimization of key components in BB5050 was studied.The main contents were shown as:(1)The Virtual Dielectric Layer Method(VDLM)was adopted to establish the dynamic model of bolts’ fixed surface, and the material parameters of dielectric layers were derived by theoretical derivation. In connection plate structure which Contains a fixed bolt joint surface for the study, to study the bolt preload, the number of bolts and bolt layout influence on the dynamic characteristics of the fixed combination of bolts of using finite element analysis techniques.(2)The 3D model of the machine tool was established by UG, finite element mode analysis of the machine tool whether to consider joint surfaces or not was conducted by ANSYS Workbench, and the former 10-order natural frequency and corresponding vibration were obtained. Preliminary determination of the lathe machine’s weaknesses.(3)Based on the experimental modal analysis, the former 10-order natural frequency and corresponding vibration were obtained by using a professional equipment to analyze modal. By contrast slotting machine modal test results and the third chapter modal finite element analysis results, proved that affect the binding surface characteristic of the dynamic performance of the machine tool, meanwhile, this paper also verifies the correctness of machine tool modeling methods.(4)Aimed at the weak links which identified by simulation, the structure and size optimization of the special slotting machine’s post pedestal was studied via Design Exploration, the availability of the structural optimization by comparative harmonic response result was presented. |
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