Design And Modification Optimization Analysis Of The Non-circular Gear

Non-circular gear is developed from conventional gear,which is used to replace the cam and four bar mechanism to transfer the nonlinear motion.It has compact structure,smooth transmission and certain bearing capacity.It is also commonly used in transmission devices,such as hydraulic pump?fluid meter and harvester,which has good prospects.Therefore,noncircular gear is getting more and more attention from designers.It is also important to improve the design system of noncircular gear.Because of the characteristics of nonlinear transmission,the radius of curvature of the non-circular gear changes with the change of the position of the rotation angle,and the force of the tooth also fluctuates in the course of transmission.Therefore,the transmission system of non-circular gears is more obvious than that of conventional gears,resulting in the aggravation of gear wear and the reduction of service life.This paper mainly focuses on the design theory of high order noncircular gear and gear modification.Based on the design theory of noncircular gear,the noncircular gear is modeled and the noncircular gear pair is modified to optimize the transmission performance.The main works in this paper are as follows:(1)Research on the design theory of non-circular gear,by adjusting the eccentricity and center distance,the non-circular gear pitch curve satisfies the conditions of closure?pressure angle?heel cutting?convexity and others,and a non-circular gear pitch curve equation satisfying the design requirements is established and use MATLAB to complete the drawing of pitch curve of non-circular gear.(2)The tooth profile design of non-circular gear is completed by analytic method and converted tooth number method.The analytic method is mainly based on the MATLAB software,and completes the establishment of the profile of the non-circular gear according to the generating principle of the analytic tooth profile.The number of converted teeth is mainly based on the invoking function of single tooth profile provided by CAXA.Based on the modeling principle of the converted tooth number method,the non-circular gear model of the converted tooth number method is established.(3)Aiming at the characteristics of the force fluctuation of non-circular gears,a modification method is adopted to optimize the transmission characteristics of non-circular gears.With the help of ADAMS View,the calculation of the tooth profile modification and the tooth profile modification of the non-circular gear is completed,and the modeling of the non-circular gear repair model is completed by using the drawing dimension software.(4)The ANSYS Workbench was used to analyze the non-circular gear pair by transient dynamic analysis to verify the modification effect.The change trend of contact stress and the distribution of contact stress on the tooth surface were analyzed.By comparing the analysis results before and after the modification,a reasonable modification amount is selected for the non-circular gear pair under the current working condition,and the modification of the non-circular gear pair is completed.The influence of two different modification methods on gear transmission characteristics is explored.