METHOD OF TRANSMISSION CONTROL FOR BELT-TYPE STEPLESS TRANSMISSION DEVICE

Drive and driven pulley necessary axial thrusts (Qdrnec, Qdnnec) necessary for power transmission without belt slippage are found in accordance with the input torque and transmission ratio; the vehicle speed and degree of accelerator opening target transmission ratio (itgt) and target rate of change of transmission ratio (ditgt) are found; this axial thrust (Qdnnec) is set as the driven pulley target axial thrust (Qdncmd); and the drive pulley axial thrust necessary to obtain the target values (itgt) and (ditgt) is set as the drive pulley target axial thrust (Qdrcmd). Then, if (Qdrcmd)<(Qdrnec), this axial thrust (Qdrnec) is altered and set as the drive pulley target axial thrust (Qdrcmd) and the driven axial thrust necessary for obtaining the target values (itgt), (ditgt) is altered and set as the driven pulley target axial thrust (Qdncmd). Drive and driven pulley axial thrust control is performed such that these target axial thrusts (Qdrcmd, Qdncmd) are obtained.