| High speed rotary electronic dobby is one of the most advanced and widely used shedding devices nowadays,which has an important influence on improving weaving efficiency and quality.Rotating variable speed mechanism is the core part of the multi arm lifting system,which determines the performance of the dobby machine.Therefore,the study of rotating variable speed mechanism has a certain engineering value to improve the performance of the rotating electronic dobby.In this paper,the development process of the dobby machine is discussed,and the mechanism and mechanism of a certain type of dobby machine are analyzed and studied deeply.And the following main contents have been completed:1)According to the actual working conditions,a three-dimensional solid model of the rotating variable speed mechanism is established,and a theoretical profile mathematical model of the most critical part of the conjugate cam is established based on the uniform motion.Combined with the kinematic simulation results of the rotating variable speed mechanism,the profile of the conjugate cam is redesigned.The kinematic simulation proves that the performance of the motion parameters after redesign is ideal.2)Based on the results of kinematics simulation,the motion parameter curve is optimized by using the statistical software Dplot.The software can quickly differentiate and integrate curves,and optimize the enlargement and reduction effects of integrals and differentials for jumping and unsmoothness of local curves.The optimized parametric curve is replaced by the cam contour mathematical model,namely the optimized cam is obtained.After kinematics simulation,the optimized cam motion parameters have been improved.3)Based on the established mathematical model of the conjugate cam profile,a conjugate cam profile calculator is designed.Because of the complexity of solving the conjugate cam mechanism parameters of minor changes that lead to many repeated calculations,the calculator provides four kinds of motion,input mechanism parameters can quickly calculate the conjugate cam profile data,effectively reduces the computation of conjugate cam contour method.4)The rotational speed of the electronic dobby is high,and it has high requirement for the reliability and stability of the mechanism.In this paper,the dynamic analysis of the rotating variable speed mechanism is carried out,and the maximum normal force of the conjugate cam at high speed is obtained,and the static analysis is carried out under this load condition.The result shows that the structural performance of the conjugate cam satisfies the requirement.Modal analysis of the main parts of the rotating variable speed mechanism is carried out,and its natural frequencies and modes are obtained.The results show that the natural frequencies of the components are much larger than the frequencies of the external vibration sources,and the rotary transmission mechanism is safe. |
