Kinematic Performance Improvement And Dynamic Characteristics Optimization Of High Speed Industrial Sewing Machine

Based on the solid-body model and vibration optimization model of the high speed industrial sewing machine, the kinematic performance and structure of this sewing machine were improved and redesigned. Main works and conclusions are as follows:The solid-body model of high-speed industrial sewing machine of GC6720MD3 type was built. The parameters such as the needle distance error and consistency of reverse and forward were optimized after the model simulation analysis. The kinematic simulation system of needle bar mechanism and thread take-up mechanism were programmed based on the kinematics analysis of the sewing machine, and it provides a tool to solve and optimize kinematics problem.Aimed to the vibration problem in high-speed industrial sewing machine owe to high-speed, vibration displacement and vibration acceleration of sewing machine panel were measured and analyzed. The impact of each par to vibration in sewing machine was compared. The needle-bar mechanism and thread take-up mechanism were confirmed as main vibration sources in high speed sewing machine.The kinematics and dynamics analysis for needle bar mechanism and thread take-up mechanism which was the main vibration source in sewing machine were researched. The mathematical models of vibration force and vibration torque were established respectively. Based on optimization objective function, balancing analysis and calculation to the needle bar mechanism and thread take-up mechanism of sewing machine were carried out. The mechanical parameters of components which was vibrating source were redesigned. The shell structure was improved through the finite element modal analysis for shell of sewing machine, and the resonance of sewing machine at work was prevented to improve the dynamic characteristics.After the shortcomings of original lubricating way in sewing machine were analyzed, the finite element analysis model of the spindle was built. The thermal characteristics of spindle were studied using ANSYS software. The oil-air lubrication method was proposed to reduce bearing heat and improve the dynamic performance of sewing machine.