Friction Analysis And Dynamic Study On Steady Running V-belt And Pulley

V-belt drive is a kind of friction transmission form that is being more and more widely used. According to the analysis on kinetics and friction of belt and pulley, the high-performance, reliable and stable operation of V-belt drive could be obtained. This project is supported with the nature and science fund from Heilongjiang province ministry of education. The research of V-belt drive makes the V-belt drive design theory and methods be improved in further step.At first the friction between belt and pulley is analyzed. There are two existing method of calculating the equivalent friction coefficient. Through the analysis of the contacting process of V belt and pulley, on the basis of the discovery that when entering, contacting and leaving the pulley, V belt not only move along the tangential circular, but along the circumferential and radial composite direction, a new reasonable formula for calculating the equivalent coefficient of friction is proposed. Among the influential factors when analyzing the friction belt and pulley, the four factors which are relative sliding velocity between belt and pulley, the radial displacement of the belt, the shear deformation of the belt and the belt's mass inertia are considered, quantitative analysis is carried out through the component of force balance equation of unit and geometric equation. Several results have been obtained:the relative sliding velocity between belt and pulley changes the friction process, non-fixed angle area brought about in the contact procedure of driving pulley and driven pulley with the belt; the additional friction force produced by the V-belt radial displacement causes changing of the bearing capacity; the friction force in the fixed angle sector between the belt and the band pulley is elaborated through the shear deformation analysis method; The belt's circumferential and the radial mass inertia have a great impact regarding the high speed belt drive and the flexible belt drive.Secondly, the dynamic modeling of V-belt and pulley is studied. V-belt is regarded as axial movable beam elements. The radial and the tangential friction forces are simulated. Different from the original V-belt mechanical model which only analyzes the one belt and pulley, drive and driven belt and pulley system's stable state mechanical model is established. In the original mechanical model, the arc of contact is a definite value, which is obviously Inconsistent with the actual situation. By application of the numerical method, the unknown boundary should be transformed to the solid boundary value firstly, then numerical solutions of contact arc, radial displacement and torque is obtained through the general BVP method under the stable state. According to this model, the belt drive vibration situation has been analyzed, and the model of vibration has been established under two kind of boundary condition, namely:fixed boundary condition model and undefined border condition model. The relation between the natural frequency and the flexible rigidity, belt's running rate, the belt length and the pulley radius ratio has been obtained through computation; the relations between oscillation amplitude and belt's flexible rigidity, oscillation amplitude and span has also been obtained. From these analysis result, we can make a conclusion that the factors affects system natural frequency and the vibration is not unique and linear, but multiple and co-effective. Therefore the analysis result is helpful in reducing the system vibration scope and avoiding resonating.Thirdly, the flat belt's finite element model has been established using finite element method, on which a V-belt model has been established using the increase law. Through model simplification and computation simulation, V-belt's stress and distortion situation in V-belt drive process is obtained. When contrasting with theoretical analysis, the simulation result is roughly consistent with the computed result, thus the finite element modeling accuracy is proved. A enhanced designing efficiency can be expected if this method applied to V-belt system.At last, the experiment and the installment for surveying fixed angle of flat belt and V-belt's real glide path in pulley has been designed on the basis of the optical fiber sensor test technology. According to the analysis and computation of experimental results, along with the simulation result's comparison, three results tendency of computation, simulation and experiment match, which further confirm the precision of the research methods.The friction analysis research and dynamics research of V-belt and pulley brings the study of belt drive forward, the friction analysis, dynamic modeling, experimental methods and conclusions acquired will provide a theoretical basis and reference for the application and design of V-belt drive.