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A hydraulic control device for controlling a belt-and-pulley type continuously variable transmission for an automotive vehicle which includes an input and an output shaft, a pair of variable-diameter pulleys provided on the input and output shafts, respectively, a transmission belt connecting the pa

A hydraulic control device for controlling a belt-and-pulley type continuously variable transmission for an automotive vehicle which includes an input and an output shaft, a pair of variable-diameter pulleys provided on the input and output shafts, respectively, a transmission belt connecting the pair of pulleys, and a pair of hydraulic actuators for changing effective diameters of the variable-diameter pulleys. The hydraulic control device further includes a shift control valve device for controlling pressures applied to the hydraulic actuators, to change the speed ratio of the continuously variable transmission over a mechanically defined range, and a controller for applying a drive signal to the shift control valve device. The controller includes a device for limiting a value of the drive signal, so as to prevent the actual speed ratio of the transmission from reaching upper and lower limits of the mechanically defined range.

대표청구항 ▼

A hydraulic control device for controlling a belt-and-pulley type continuously variable transmission for an automotive vehicle which includes an input and output shaft, a pair of variable-diameter pulleys provided on the input and output shafts, respectively, a transmission belt connecting the pair

A hydraulic control device for controlling a belt-and-pulley type continuously variable transmission for an automotive vehicle which includes an input and output shaft, a pair of variable-diameter pulleys provided on the input and output shafts, respectively, a transmission belt connecting the pair of pulleys, and a pair of hydraulic actuators for changing effective diameters of the variable-diameter pulleys, said hydraulic control device comprising: a shift control valve device for controlling pressures applied to said hydraulic actuators, to change an actual speed ratio of the continuously variable transmission over a mechanically defined range; and control means for applying a drive signal to said shift control valve device; said control means including limiting means for limiting a value of said drive signal, so as to prevent said actual speed ratio of the transmission from reaching upper and lower limits of said mechanically defined range.