Patent ID: 8543299

Claim:
A control device for an automatic transmission that includes an automatic speed change mechanism with an input shaft connected to a driving source and an output shaft connected to a drive wheel and a plurality of friction engagement elements engaged based on an engagement pressure supplied to each hydraulic servo, in which a transmission path between the input shaft and the output shaft is changed based on engaged states of a predetermined number of friction engagement elements of the plurality of friction engagement elements to form a plurality of shift speeds; and a regulated pressure supply portion that can freely regulate a line pressure to be supplied as the engagement pressure individually to each of the hydraulic servos, and which selectively engages the friction engagement elements in accordance with the shift speeds, the control device comprising: an input torque detection unit that detects an input torque input to the input shaft; and a controller that: determines torque distribution of the predetermined number of friction engagement elements that form the shift speeds; and calculates a transmission torque of the predetermined number of friction engagement elements based on the input torque and the torque distribution and sets the engagement pressure to obtain a torque capacity that can transmit the transmission torque, wherein the controller sets the engagement pressure such that when an additional friction engagement element of the plurality of friction engagement elements engages based on the line pressure while the predetermined number of friction engagement elements are engaged in a normal state to form a shift speed, one friction engagement element of the predetermined number of friction engagement elements and the additional friction engagement element is caused to slip while the other friction engagement elements of the predetermined number of friction engagement elements and the additional friction engagement element do not slip.