Study On Finite Element Analysis And Optimum Design Of The Gearbox In Twin-Screw Extruder

The twin-screw extruder is one of the important equipment in producing and processing the high polymer materials, and it has been more and more widely used in our country. As one of important parts in the twin-screw extruder, the gear box has the functions of making the motor slow down and distributing the power on average. Because of the special demand of Twin-screw extruder screw about spacing, the designs of gears and gear box have much difficulty. It has a high requirement on the choice of gear parameters and the structure design of the gear box.With the development of the finite element technology, engineers have paid more and more attention to computer-aided analysis (CAE). ANSYS workbench is a new interface of ANSYS software. Compared with traditional ANSYS operator interface, workbench has a function of assembly automatic analysis, automatic meshing,efficient optimization and so on. Which greatly save the operation time of the analysis. The user-friendly analysis interface allows designers to make finite element analysis in an intuitive and convenient way.This paper takes the gearbox of SHJ-65A twin-screw extruder in Nanjing Chengmeng Machinery Company as a study subject, uses Pro/E and ANSYS as mainly application software. The mainly research contents include three parts:At first, the mechanical model of gearbox is established and the transmission forces between the engage gears in gearbox are calculated. According to the gear transmission forces and drive torque, the support reaction forces of the gear shafts can be calculated, the force loads of the gear box casing is also can be get at the same time;3D models of the main components in the gear box based on Pro/E are established, and then the whole assembly of the gearbox is completed.Secondly, the simplified models of the gearbox casing and gear assembly are imported into ANSYS workbench. And then the finite element models are created in workbench, constraints and force loads are added on them as well. The static analysis of the gear pair and gearbox casing are conducted in static analysis module; The modal analysis of the gearbox casing and gear assembly are conducted in dynamic analysis module. The static analysis and modal analysis results of the gearbox casing provide a theoretical basis for the optimization design.Finally, according to the results of static analysis and modal analysis, a structural transformation of the gearbox casing is completed in order to reduce the quality of the gearbox casing, eliminate the phenomenon of local stress concentration and reduce the deformation of the box; The maximum deformation and first natural frequency numerical are taken as the target variables, the four basic dimensions of the gearbox casing are taken as design variables, and then a Size Optimization of the gearbox casing is conducted; Compared with the gearbox casing before optimization, the amount of deformation is reduced, the frequency value is increased and the stability of the transmission case is further improved. A vibration testing is done for improved gearbox in order to verify the stability and feasibility of the improved gearbox casing.