| The metal V-belt continuously variable transmission (CVT) is favored by more and morecar‘s manufacturers because of its excellent performance such as fuel economy and ridingcomfort. As a kind of friction drive the CVT transmission efficiency is not high, it hasbecome the key reason for restricting the large-scale development. In order to improve thetransmission efficiency and transmission reliability, the transient dynamics model aimed toreveal the relationship among the tribological characteristics-slip ratio-clamping force-efficiency in the metal belt transmission was built, which can promote the slip controltechnology to mature applications, and further improve the CVT transmission efficiency.Based on the National Natural Science Foundation project analysis and investigatethe CVT oil film traction and wear characteristics of slip control mode‘, this paper focuses onthe metal belt CVT transient dynamics and power loss of slip control mode, and thebottleneck of the slip control strategy face in the development were excellent solved. Themainly works had done as follows:1．A method calculate the drive pulley idle arc angle was derived, which based on theresearch of metal belt CVT transmission mechanism and analysis of the influence whichmany motion feature in metal belt drive process such as axial deflection, gap of belt elements,multi-directional movement, non-continuous contact and slip, affected on the force operatedon metal belt and pulleys, meanwhile the difference of the force impact on belt elementsbetween the idle arc of the drive pulley and the active arc metal was taked into account. Fromthe perspective of analysis the friction between band pack and belt elements and between thebelt elements and belt pulley of metal belt CVT, the occurrence mechanism of the slip and theimpact the slip to the torque transmission were studied, thus the variation trend ofcompressive force in the belt elements and tensile force in the band pack under differentworking conditions were obtained.2．In comprehensive considered all kinds of run features in metal V-belt driveinfluenced to the force exerted on the metal V-belts and pulleys, according to the kinematicsrelationship between the metal V-belt and pulleys of the CVT, derived the mechanicsrelationship of compressive force in the belt elements, tensile force in the band pack andaxial clamping force of driver and driven pulley, the friction-drive mechanical model of CVTwas put forward. On this basis, the effect of friction coefficient, slip rate, metal V-belt pathand other factors on the CVT transmission performance were analyzed.3．Based on the CVT friction drive model established in this paper, considering the influence of slip friction, power loss of the CVT speed change mechanism is divided into fourparts and studied it intensively, each part of the power loss computational formula is derived.On this basis, each part of the power loss under different transmission ratio were studied, andthe relationship between the transmission coefficient and slip ratio was ascertained. the sliprate was dynamic analyzed, meanwhile explicit various of factors effected on the slip ratio.4. Comparative analysis the common estimation method of slip ratio, then completedthe design of sliding control experimental system in this paper. This system needs to accuratemeasure the slip ratio, transmission efficiency and clamp force and other factors of the metalbelt CVT, for verifying the mathematical model describe the relationship among metalV-belt tribological properties-slip ratio-clamp force-transmission efficiency established inthis paper. |
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