| The function of the beating-up mechanism is to convert the uniform rotation of the spindle of the loom into the irregular intermittent oscillation of the beating sley,so as to push the weft introduced into the shed to the loom,tighten the weft and make the warp and weft yarns interweave to form the fabric.At present,the market beating-up mechanism is mainly divided into two types: conjugate beating-up mechanism and linkage beating-up mechanism.The conjugate beating-up mechanism is easy to implement beating-up sley middle of the back 240 ° full pause time,but the design of the conjugate processing demand is high,and wear for a long time can beating-up mechanism performance degradation;The four-bar beating-up mechanism is simple in structure and convenient in processing,but the position of the back center of weft beating is not enough to be approximately stopped.The six-link beating-up mechanism can achieve a long approximate pause time in the back center,but the acceleration of the sley changes greatly during the beatingup process,which limits its application in high-speed and wide reed loom.In view of the above problems,this paper proposes a new type of loom weft beating mechanism,namely Fourier noncircular gear planetary wheel system weft beating mechanism,to establish its mathematical modeling,reverse design,virtual simulation and experimental verification,laying a foundation for the serial design of products.1)The structure and working principle of beating weft mechanism are introduced.On the basis of the technical characteristics of the beating mechanism and the requirements of the beating motion,the acceleration curve of the triplex Hermite interpolation polynomial as the transition section was selected as the ideal motion law of the playing reed,which had good motion characteristics.2)The inverse kinematics mathematical model is established,and the nodal curve equation of two-stage non-circular gear is obtained according to the movement law of the reed and the known parameters.Based on MATLAB,the reverse design and motion simulation software of the beating weft mechanism is programmed.In combination with the requirement of beating weft process,a group of better mechanism parameters are obtained through man-machine interaction optimization.3)The dynamic model of the beating-up mechanism is established,and the force of each hinge point and gear meshing point is analyzed by using the method of solving the sequence of dynamic equations.Combining with the software of dynamic assistant analysis,the parameters were adjusted,and the dynamic analysis was carried out on the planetary gear system of noncircular Fourier gear under different parameters.4)Based on the results of dynamic analysis,HYPERMESH and LS-DYNA software were used to conduct dynamic contact analysis of non-circular gear meshing process,and the maximum stress in the meshing process was determined to check the gear strength.The force of gear teeth in the process of meshing is analyzed qualitatively according to the order of meshing.5)The 3D modeling and assembly of the beating-up mechanism are carried out,and virtual simulation of the mechanism is conducted by using the virtual prototype software ADAMS.Then on the basis of the structural design of the test bench processing and experimental verification.At last,the motion law of the virtual simulation of the reed is compared with that of the virtual simulation and experiment to verify the correctness of the theoretical analysis model. |
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