Experimental Study On Speed Ratio Mechanism Of Metal Belt Type CVT

Continuously variable transmission (CVT) is a perfect transmission for Automobile.The transmission pair, which includes metal belt and pulley, is the key component of metalbelt type CVT. Speed Ratio mechanism of the metal belt type CVT is one of the importanttheoretical basis to control it, master the speed Ratio mechanism directly affect the controlof CVT and its good performance. At present most of the metal belt type CVT car adoptshydraulic pressure hydraulic system, electronic control scheme, according to data showsmetal belt type CVT transmission system consumes a large part of the total input energy.To develop new energy-saving hydraulic system and efficient control strategy, it must carryon the experimental study on the speed Ratio mechanism of CVT, and mastery. So thespeed change mechanism of CVT is studied on the CVT transmission system and controlstrategy of research and development have very important significance. This article fromthe basic theory of metal belt type CVT has carried on the theoretical research on its speedRatio mechanism; In the design of speed change mechanism testing CVT test-bed; Specificresearch contents are as follows:First of all, on the metal belt type CVT transmission principle, relevant analyzinglearning: metal and slip between steel ring into the principle and formula is derived; Andtheoretical analysis of CVT metal belt of the stress distribution under different speed ratio,find out the causes and distribution. Articles analysis the transmission efficiency andtransmission ratio, torque, the relationship between changes for speed ratio andtransmission efficiency to provide theoretical basis for the correlation.Second, the theoretical formula with axial thrust is deduced; In steady state underno-load and load two cases to analyze the relationship between thrust ratio and speed ratio,the theory formula, calculate and draw the curve; In-depth analysis of the characteristics ofthe speed ratio change hysteresis and thrust ratio, combined with radial friction force andtransmission efficiency is deduced under the no-load and load of hysteresis theory formula,calculate and draw the curve.Again, through the analysis of the CVT transmission mechanism, the design includedsuch as area of CVT test chamber and double pressure control circuit of the CVT test-bed,the CVT speed ratio hysteresis characteristics test.Finally, the design of CVT speed ratio hysteresis characteristic test experiment scheme,draw relevant data and to prove the validity of the metal belt type CVT speed ratio changehysteresis characteristics, combined with the theoretical formula analysis difference, and modified theory formula is presented.In this paper, metal belt type CVT transmission Speed Ratio mechanism as the center,analyses the transmission efficiency and the radial friction, the radial component of thefriction coefficient and relevant influence factor, proposed the metal belt type CVT speedratio change hysteresis characteristics, verified by experiment. These variable speedmechanism theory and experimental study on the improvement of the basic theory of metalbelt type CVT and test and for the development of domestic metal belt type CVT are allhave the important guiding significance and practical value.