Experimental and Numerical Investigations for Analysis of Temperature Rise on the Traction Contact Surface of Toroidal Cvts

Temperature rise in traction contact areas is one important factor that influences traction coefficient. For examining the influence of temperature rise on the traction coefficient, it is necessary to first clarify temperature rise in the traction contact area. In this article, temperature rise in the traction contact areas is discussed in three major parts. First, measured temperature distributions on the traction contact surface under conditions of high rolling speed and minute amounts of sliding and spinning, such as those which are found in a toroidal CVT, using a twin-disc test machine and thin-film platinum sensors are shown. Second, the above experimental results are compared with results from a traction analysis program (REIB99). Characteristics of calculated results were qualitatively in good agreement with measured results. Although the calculated absolute temperature values were substantially lower than the measured values, it was confirmed that measured temperature rises were two times higher than calculated results under any condition in the experimental range. Thus, we concluded that the traction analysis program is capable of simulating the tendency of temperature rise on a traction contact surface. Finally, temperature distributions on the traction contact surface of full-and half-toroidal CVTs were calculated using REIB99. The influence of variator ratio, input torque, and input rotational speed on temperature rise in a toroidal CVT is discussed.