Kinematic Analysis And Optimization Of Shedding Drive Mechanism For Needle Type Leno

The skein shedding mechanism is an important component of the leno loom,and its function is to drive the warp yarns to make a skein shedding movement.At present,there are two methods for realizing warp skein weaving: heddle type and needle row type.Among them,the needle-row twisted shedding mechanism has the advantages of high reliability,simple structure,long cycle life and convenient maintenance and operation.It is widely used in the weaving of leno weaving,but its variety adaptability is limited.With the increase of weaving speed,the movement law of the needle row has a particularly prominent influence on the warp breaking,especially in the glass fiber stranding industry,reducing the friction and squeezing between the warp yarn and the needle row,reducing the warp break and increasing the speed of the loom It is of great significance.This paper takes the needle row type servo twisted heald frame drive mechanism as the research object,and mainly does the following research:1)According to the physical surveying and mapping related parts of the loom,extract the schematic diagram of the twisting shedding drive mechanism,using the vector method to analyze the kinematics of the twisting shedding mechanism,establishing the analysis model for solving the movement law of the lower needle row,and obtaining the movement law of the lower needle row.According to the movement law of the lower needle row,the warp yarn movement track is analyzed,and the cause of the warp broken is analyzed.A software for analyzing the movement law of the lower needle row is designed by Matlab.2)In Pro/E,a three-dimensional modeling of the drive mechanism of the twisted opening was established,and the motion simulation was performed.The simulation results were compared with the calculated results to verify the correctness of the model.Use Pro/E to measure the total kinetic energy of the mechanism system and the driving torque on the drive shaft,analyze the influence of the quality of the heald frame,the longitudinal stroke of the heald frame and the speed of the drive shaft on the dynamic performance of the mechanism,in order to improve the dynamic performance of the mechanism provide evidence.3)The effect of the starting position of the eccentric disc,the conjugate cam and the connecting rod on the movement of the lower needle row is studied,and the defects of the mechanism are analyzed.It is found that the longitudinal movement of the lower needle row is only affected by the conjugate cam,while the lower needle row moves laterally.The law is not only affected by the initial position of the eccentric disc,but also by the combined action of the conjugate cam and the connecting rod,and the ideal motion law of the lower needle row is proposed to prepare for the subsequent optimization design of the mechanism.4)According to the ideal motion law of the lower needle row,a new mechanism configuration is designed to weaken the positional correlation between the longitudinal and lateral movement of the lower needle row,and the contour curve of the conjugate cam is designed to optimize the servo motor rotation angle relative to the loom The movement law of the main shaft corner changes the movement law of the lower needle row and reduces the contact time between the warp yarn and the steel needle.