Design Theory And Meshing Contact Characteristics Analysis Of Various Conjugate Contact Curves For Line Gears Based On Pitch Pattern

As an important component of mechanical equipment,the performance of gear transmission mechanism not only determines the quality and level of mechanical equipment,but also reflects the technical level of national industrial and defense high-end equipment,play a pivotal role in strategic position.At present,the gear mechanism is developing in the direction of small size and light weight,how to miniaturize the gear and improve its transmission performance have become one of the most important directions in the frontier research of mechanical science.As a transmission mechanism with conjugate curves meshing,line gear is of great significance to the manufacture of micro equipment.The researches of line gear and gear meshing theories are both systematically summarized and discussed in this dissertation.Based on the previous research theory of the contact curve of line gear used in skew shaft transmission,aiming at the difficulty of designing other kinds of contact curves in a given space of pitch cylinder,the design theory of various conjugate contact curves for line gears based on pitch pattern is proposed,we collectively referred the line gears on the same rotary as pitch pattern line gears,moreover,corresponding finite element analysis and transmission error test are carried out to verify the feasibility of the contact curve design.The research work of this dissertation carried out is as follows:Firstly,a design theory of contact curves based on pitch pattern is proposed.Established the transformation equation of space coordinate system for line gear,and the side of threedimensional cylinder is expanded into two-dimensional plane,then derived the function which is generally applicable to the transformation from two-dimensional expansion plane to threedimensional cylinder space.The pitch cylinder and pitch platform are defined and the straight line,the sine curve and the logarithmic curve are selected as the two-dimensional expansion plane contact curves.Secondly,the geometric contact characteristics of contact curves based on pitch pattern are studied.Defined the pressure angle,the sliding rate and the curvature of contact curves and carried out corresponding formula calculations respectively.The function change of geometric contact characteristics is drawn to analyze the relationship between the change of contact curve shape and the values of geometric contact characteristics.Thirdly,carried out finite element analysis for the line gears based on the same pith pattern.According to design formulas of the contact curves for straight line,sine curve and logarithmic curve,corresponding design formulas of the center curves of line gears are deduced,and the three-dimensional simulation models of line gears are established by three-dimensional drawing soft.The maximum stress and meshing stiffness calculation formulas of line tooth are deduced by elastic Hertz contact theory.Through the finite element numerical simulation software,the maximum stresses and meshing stiffness of several different line gears are completely analyzed.Fourthly,tested the kinematic transmission performance of line gears based on the same pitch pattern.To measure the torque and rotation speed of line gears,a multiple degrees of freedom kinematic test platform is established.Then,the 3D physical models of line gears are printed by using the method of stereo lithography appearance.The transmission errors of three kinds of line gears based on the same pitch pattern are measured,and researched the transmission errors under different rotation speeds of driving gears.