Patent ID: 7331900

Claim:
A shift control apparatus for a continuously-variable transmission, comprising: a primary pulley coupled with an engine for a vehicle, and adapted to vary groove width thereof in accordance with hydraulic pressure within a primary chamber; a secondary pulley connected with the primary pulley by a belt, and adapted to vary groove width thereof in accordance with hydraulic pressure within a secondary chamber; a stepping motor that operates as a shift actuator adapted to vary a speed ratio by varying the groove width of at least one of the primary pulley and the secondary pulley; a line pressure adjusting section adapted to adjust a discharge pressure of an oil pump, to produce a line pressure from which the hydraulic pressures within the primary and secondary chambers are produced; a secondary-pressure adjusting section adapted to adjust a secondary pressure corresponding to the hydraulic pressure within the secondary chamber, on the basis of the line pressure; and a control section configured to control the shift actuator, the line pressure adjusting section, and the secondary-pressure adjusting section, the control section including a fail determining section configured to determine whether the shift actuator is under a failed condition, and the control section being configured to carry out a fail-safe shift-actuator fixing control to fix an operating state of the shift actuator, under the condition where the fail determining section determines that the shift actuator is under the failed condition, and being configured to carry out a fail-safe hydraulic control to bring the line pressure to its upper limit pressure and bring the secondary pressure to its maximum pressure, under the condition where a control-start criterion predetermined to secure driving performance of the vehicle is satisfied at the time of the failed condition.