Patent ID: 8565987

Claim:
A shift controller for an automatic transmission capable of shifting in a manual mode in which the automatic transmission shifts down in accordance with a driver's manual downshift operation, and automatically shifting up to decrease a gear ratio when a rotational speed of a rotation power source reaches a predetermined acceptable upper limit speed in the manual mode, wherein a hysteresis forbidding the downshift caused by the driver's manual downshift operation is provided between an acceptable upper limit speed of any of rotating bodies which are an output shaft of the automatic transmission, a rotating member in the automatic transmission, and an output shaft of the rotation power source, the acceptable upper limit speed being a rotational speed at which the automatic upshift is enabled in the manual mode, and an upper limit downshift permission speed which is an upper limit of a rotation speed of the rotating body in a manual downshift permission region wherein the downshift is performed in accordance with the driver's manual downshift operation in the manual mode, the hysteresis is set, depending on a torque of the rotation power source or a physical quantity correlating with the torque as a parameter and the hysteresis is set to be smaller as the torque of the rotation power source decreases or as the physical quantity correlating with the torque changes with the decrease in the torque of the rotation power source, whereby the manual downshift permission region where the downshift is performed in accordance with the driver's manual downshift operation is expanded to a higher rotational speed region where the rotating body is rotated at higher speed.