| The tripod joint has a wide range of applications in mechanical systems and is the most widely used plunging joint in the drive shaft assembly of an automobile because of its advantages such as strong load capacity,high efficiency and good reliability.However,with the elevation of people’s requirements for the reliability of the mechanical system and the quality of work and life,the problems caused by the sliding friction between the roller and track of a tripod joint such as wear,vibration,noise etc.are increasingly prominent.To this end,this paper proposes a novel double roller tripod joint,and verifies its ability to solve the structural defects of a tripod joint,eliminate the relative sliding between the rollers and tracks,reduce the friction between the two,and improve the performance of a tripod join by analyzing its kinematics and dynamics.The main research work of this paper is summarized as follows:(1)The method for the structural design of the double roller tripod joint is studied.Based on the principles of the durability test of a universal joint,a bench test is designed to measure the relative displacement and rotational angle between the roller and track of a double roller tripod joint,and its kinematic characteristics are thereby experimentally studied.By bench test,the generated axial force and high frequency plunging force of a double roller tripod joint are measured,and its dynamic characteristic are thereby experimentally studied.The results show that double roller tripod joints greatly improve the 3 performance indices of the relative pitch angle between the roller and track,generated axial force and high frequency plunging force.(2)The kinematic model of a double roller tripod joint is established,and the analytical expression of its kinematic parameters are derived.The model is verified by experiments.By comparing the kinematic characteristics of a double ball roller tripod joint and tripod joint,it is shown that the double roller tripod joint has the kinematic performance advantages of good constant velocity performance and no relative sliding between the roller and track.(3)Based on the principles of conjugate surfaces,the kinematic model with fit clearances of the double roller tripod joint is established.Based on the proposed method,the influence of the fit clearances between the rollers and tracks as well as the rollers and trunnions on the kinematics characteristics of the double roller tripod joint is analyzed.The results show that the kinematic characteristics of the double roller tripod joint are not sensitive to the fit clearances,so proper fit clearances can be designed between the rollers and tracks and between the rollers and trunnions in a double roller tripod joint to improve its reliability,durability,manufacturability and assemblability.(4)The dynamic model of the double roller tripod joint is established.The model is verified by experiments.By comparing the dynamic characteristics of a double roller tripod joint and tripod joint,it is shown that the double roller tripod joint has the dynamic performance advantages of small friction forces between the roller and track,generated axial force and high frequency plunging force. |
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