Patent ID: 8831846

Claim:
A controller of a continuously variable transmission that controls thrusts of a primary pulley and a secondary pulley through feedback control based on a difference between a target gear ratio and a current gear ratio, wherein the controller controls a gear shifting speed that is a changing speed of a gear ratio, the controller comprising: a variable amount calculating unit that calculates the thrust of the primary pulley, under the assumption that the thrust of the secondary pulley is equal to an upper limit thrust set by taking into consideration the durability of a belt while maintaining a ratio of the thrusts of the pulleys under the current gear ratio, based on the thrust of each pulley under the current gear ratio and the upper limit thrust, and the variable amount calculating unit calculates a difference between the calculated thrust and a lower limit thrust, which is required to maintain the current gear ratio without the belt slipping on the pulleys that the belt is wound around, as a variable amount of the thrust of the primary pulley; a limit speed calculating unit that calculates a limit gear shifting speed, which is a limit value of the gear shifting speed, based on the variable amount of the thrust of the primary pulley calculated by the variable amount calculating unit; and a guard value calculating unit that calculates a guard value for limiting the target gear ratio based on the limit gear shifting speed calculated by the limit speed calculating unit; wherein the thrust of each pulley is controlled through feedback control based on the difference between the target gear ratio, which is limited by the guard value calculated by the guard value calculating unit, and the current gear ratio.