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A simulation technology has been developed to predict the transmission efficiency of a metal pushing V-belt and pulleys that make up the drive system of a continuously variable transmission (CVT). When a CVT operates in an actual vehicle, pulley thrust pressure is adjusted by feedback control to maintain a speed ratio. This feedback control has been implemented, for the first time, in an existing simulation that predicts the dynamic behavior of a metal V-belt using explicit structural analysis. The new simulation enables stable control of a target speed ratio when appropriate gains are set for each analysis condition.

The project discussed in this paper focused on the torque transmission characteristics of facing materials in order to enable desktop prediction of the torque capacity of the multiple plate clutches used in automatic transmissions (AT). The amount of torque transmitted by the facing materials themselves is affected by the temperature, contact pressure and sliding velocity of the friction surfaces. An analytic model of a test apparatus was therefore constructed, and the friction properties of the facing material were identified from the amount of torque transmitted. Next, a torque capacity prediction model, able to simulate the flow of torque transmission in the transmission, was constructed. This enabled torque capacity in an operating AT to be predicted for the first time with an accuracy to within ±5% of measured values.

A simulation method enabling simultaneous prediction of dynamic behavior and stress distribution on an individual element has been developed for durability evaluation of dynamic strength of metal pushing V-belts. The finite-element-method that enables contact analyses in time history with large-scale model was adopted to reproduce the dynamic behavior of the V-belt in high rotational speed range of CVT. This paper focuses on the element strength in actual CVT operation, and also discusses modifications made to the previously reported simulation method to enable the prediction of detailed stress. A new technique named inertia-relief is introduced, which does not require the application of constraint conditions when calculating the detailed stress on element in respectively. This results in allowing the stress distribution on any element to be found at any position on the trajectory of the V-belt and the elastic deformation of the element to be identified.