抄録
The purpose of this study is to investigate the behavior of CVT to consider the change of the transmitting efficiency during shifting. The apparatus consists of driving and driven pulleys whose groove width was adjustable, dry hybrid V-belt, a variable speed AC motor and an electric powder brake. The flange of the driven pulley was subjected to a constant thrust by an oil-pressured actuator. Pulley thrust, rotating speed and applied torque was measured in the test. The speed ratio (i) which was defined as the reduction ratio of number of revolutions of driven pulley to that of driving pulley was changed from 2.2 to 0.8 to execute shifting up motion of CVT. To change the width of pulley grove, applied thrust force (Qdn) to the driven pulley was linearly increased from 1000 to 1500N. Momentary transmitting efficiency which was defined as the momently variation of transmitting efficiency at shifting state was evaluated by measuring the change of torques and numbers of revolutions of the driven and driving shaft, respectively. Non-dimensional momentary transmitting efficiency (η) (normalized efficiency by that at certain condition) was improved during shifting with increase of shifting time (ti) in any conditions of shifting time. Non-dimensional momentary transmitting efficiency (η) was improved during shifting with increase of input number of revolutions (Nin) in any conditions of input number of revolutions. The radial displacement per one pulley revolution (λ_<rev>) was an index to evaluate the changes of non-dimensional momentary transmitting efficiency (η) and driving pulley thrust (Qdr) during shifting. The λrev is not only an index to evaluate the changes of non-dimensional momentary transmitting efficiency during shifting (η)) and driving pulley thrust (Qdr) but also an index to evaluate the changes of mean transmitting efficiency during shifting (η_<mean>) and mean driving pulley thrust during shifting (Qdr_<mean>).
