| 摘要 |
PURPOSE:To improve the control response by controlling a spool valve chip in a speed change control valve which controls respective hydraulic cylinders for modifying the effective diameters of a pair of variable pulleys by means of the control hydraulic pressure being fed from a control oil pressure source and controlled through a solenoid control valve. CONSTITUTION:In a hydraulic control circuit for a continuously variable transmission 14 where a transmission belt 24 is entrained about respective variable pulleys 20, 22 having the effective diameters being modified by means of the hydraulic cylinders 26, 28, first pressure regulation valve 48 for flowing a portion of the working oil in a delivery side oil path 50 of an oil pump 42 to an oil path 52 and controlling the first line oil pressure is provided. Second pressure regulation valve 58 for flowing a portion of the working oil in the oil path 52 to a drain oil path 60 and controlling the second line oil pressure is also provided. Furthermore, a speed change control valve 44 for feeding the working oil to one of said hydraulic cylinders 26, 28 and regulating the speed ratio of the continuously variable transmission 14 is provided with the spool valve chip thereof being driven by the oil pressure which is fed from the control oil pressure source (110, 112) and controlled by solenoid valves 74, 76. |
