Patent ID: 8002654

Claim:
A control system for controlling a belt-type continuously variable transmission having a pair of pulleys including a first pulley which sets a speed change ratio and a second pulley which sets a clamping pressure for clamping the belt, in which the first pulley is provided with a first oil chamber to which an oil pressure is fed to reduce a groove width of the first pulley, in which the second pulley is provided with a second oil chamber to which an oil pressure is fed to clamp the belt and a capacity of the second oil chamber is varied in accordance with a change in the groove width of the first pulley, and in which the oil pressure in the second oil chamber is controlled in accordance with a deviation between a target oil pressure and an actual oil pressure, comprising: an electronic control unit, wherein the electronic control unit detects a change in the capacity of the second oil chamber on the basis of a control amount of the oil pressure of the first oil chamber, wherein the electronic control unit alters a variable to control the oil pressure of the second oil chamber on the basis of the change in the capacity of the second oil chamber, wherein the electronic control unit performs a feedback control that controls the oil pressure of the second oil chamber in accordance with a feedback gain for at least one of proportional and integral control, wherein the electronic control unit selects a first gain in a case where the change in capacity of the first oil chamber is below a predetermined threshold, and selects a second gain larger than the first gain in a case where the change in capacity of the first oil chamber is not below the predetermined threshold, wherein the first gain and second gain are predetermined constants, and wherein, when the second gain is selected, a difference between an actual clamping pressure for clamping the belt and a clamping pressure for clamping the belt set by the electronic control unit is less than the difference would be if the first gain had been selected.