Study On Flexible Multibody Dynamics Of Double Involute Gears Considering In The Effet Of Tooth Surface Pitting

With the high-quality development of economic society,gears,as the core components of machinery,also urgently need to develop in the direction of high precision and sharpness.Tooth surface pitting affects the overall transmission performance of gear systems.Double involute gear is a new type of gear that combines the advantages of stepped double circular arc gear and involute gear.Its end face unilateral tooth profile curve consists of two segments of upper and lower stepped involutes and a transition curve.At present,the research on the dynamic characteristics of double involute gears under normal conditions is more in-depth,and the research on the dynamic characteristics of gears considering the impact of tooth surface pitting is less.Based on the theory of flexible body and multibody dynamics,this paper studies the time-varying meshing stiffness and dynamic characteristics of double involute gears considering the impact of tooth surface pitting.The specific research content is as follows:(1)Establish a three-dimensional model of double involute gears,and use finite element modal analysis to make the gears flexible;Through virtual prototyping technology,considering Hertz contact theory,collision contact theory,flexible body theory,and multibody dynamics theory,a multibody dynamic model of double involute gears in flexible and rigid body states was established,and the dynamic characteristics of two different gear models were analyzed.Based on error analysis,the accuracy of the flexible multibody dynamic model of double involute gears was verified.(2)Considering the influence of tooth surface pitting on the contact line length and time-varying meshing stiffness of double involute gears,a mathematical model for the contact line length and time-varying meshing stiffness of double involute gears under three types of tooth surface pitting was established;The influence of different pitting conditions on the contact line length of double involute gears was analyzed,and the relationship between the contact line length and meshing stiffness was studied;Establish a finite element model for time-varying meshing stiffness of double involute and ordinary involute helical gears with three types of tooth surface pitting,verify the accuracy of the algorithm,and analyze the impact of tooth surface pitting on the meshing stiffness of the two gears.(3)Based on the theory of flexible multibody dynamics,a flexible multibody dynamic model for double involute and ordinary involute helical gears with three types of tooth surface pitting was established,and a 2-degree of freedom torsional dynamic model for double involute gears was established;The effects of different tooth surface pitting conditions on the dynamic characteristics of the two gears,such as dynamic meshing force and angular acceleration,were studied;The effects of rotational speed and torque on the dynamic characteristics and tooth vibration deformation of two types of gears with consideration of tooth surface pitting are studied.(4)Carry out experiments on a closed gear transmission experimental platform to test the vibration acceleration of double involute gears under no-load,constant speed to torque,and constant torque to speed conditions;Analyze the temperature rise of lubricating oil,transmission efficiency,and changes in gear vibration acceleration under different viscosity lubricating oil during gear transmission;Comparative analysis of experimental and simulation results of gear vibration acceleration verifies the accuracy of the flexible multibody dynamic model for dual involute gears.