Hydraulic control apparatus for vehicle continuously variable transmission, having means for limiting increase in input shaft speed after the speed rises to predetermined level with vehicle speed

摘要

A hydraulic control control apparatus for controlling a speed ratio of a vehicle continuously variable transmission, which includes a device for producing a first pressure varying with the input shaft speed of the transmission, a device for producing a second pressure varying with the currently required output of the vehicle engine, a device for producing a third pressure varying with the vehicle speed, such that a rate of increase in the third pressure is limited after the vehicle speed pressure reaches a predetermined upper limit which varies with the second pressure, and a shift control valve device including a valve spool operated to control the hydraulic actuator for changing the speed ratio so as to shift-down the transmission, in relation to an increase in the second pressure and an increase in the vehicle speed pressure, and changing the speed ratio so as to shift-up the transmission, in relation to an increase in the first speed pressure.