Control device of continuously variable transmission for vehicle

A control device of a continuously variable transmission for a vehicle having a pair of variable pulleys with variable effective diameters of an input-side variable pulley and an output-side variable pulley and a transmission belt wrapped around between the pair of the variable pulleys, the control device controlling an input-side thrust force of the input-side variable pulley and an output-side thrust force of the output-side variable pulley to set an actual gear ratio to a target gear ratio and preventing a slip of the transmission belt, the continuously variable transmission having a lowest-speed-side gear ratio determined by mechanically preventing movement of an input-side rotating body moved in an axial direction for varying an effective diameter of the input-side variable pulley, the control device comprising:

• a rotation sensor value accuracy determining portion configured to determine whether both detection values of an input shaft rotation speed and an output shaft rotation speed reflect an actual rotation speed;
• a maximum gear ratio arrival determining portion configured to determine, when the rotation sensor value accuracy determining portion determines that at least one of the detection values of the input shaft rotation speed and the output shaft rotation speed does not reflect the actual rotation speed, whether the actual gear ratio calculated based on the input shaft rotation speed and the output shaft rotation speed is already the lowest-speed-side gear ratio;
• and
• a continuously variable transmission control portion configured to set, when the rotation sensor accuracy determining portion determines that at least one of the detection values of the input shaft rotation speed and the output shaft rotation speed does not reflect the actual rotation speed, a target input-side thrust force and a target output-side thrust force to be target thrust forces for maintaining the lowest-speed-side gear ratio and preventing the slip of the transmission belt, and
• based on whether the actual gear ratio is already the lowest-speed-side gear ratio, the continuously variable transmission control portion changing values of the input-side thrust force and the output-side thrust force each of which is independently controlled to adjust a pressure in order to obtain the target thrust forces for maintaining the lowest-speed-side gear ratio.