| 摘要 |
PURPOSE:To reduce a drive loss in a pump as well as to improve fuel consumption in a vehicle and durability in a transmission belt, by lowering the extent of second line hydraulic pressure to be interconnected to a variable pulley at the secondary side temporarily at gear shifting when speed ratio of a continuously variable transmission is varied in the decreasing direction. CONSTITUTION:In this belt type continuously variable transmission 14 where output of an engine 10 is transmitted via a clutch 12, a transmission belt 24 is rolled on each of variable pulleys 20 and 22 attached to each of turning shafts 16 and 18, while it is provided with each of cylinders 26 and 28 which alters each effective diameter of these pulleys 20 and 22. And, on the basis of each signal out of respective speed sensors 90, 92, etc., pressure-regulating valves 48, 58 and magnetic solenoids 74, 76 are driven each by a controller 94, whereby each line hydraulic pressure and speed ratio of the continuously variable transmission 14 dependending upon the quatient of these turning shafts 16 and 18 are all controlled. In this case, a lowering quantity of second line hydraulic pressure at gear shifting when the speed ratio is decreased is determined according to a variation of rotational speed of the turning shaft 16 at the primary side.
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