| 摘要 |
PURPOSE:To keep off a slip in a V-belt as well as to improve the speed change responsiveness ever so better, by connecting a port, which is supplied with line pressure when a spool in a speed change control valve is displaced beyond the specified value in a direction of enlarging a speed change ratio, to a pressure boosting port of a line pressure relief valve. CONSTITUTION:When stepping on an accelerator pedal so quickly, a speed change controller 300 gives a step motor 110 an opening signal quickly rotates a pinion gear 110a toward the large side of a speed change ratio. A spool 174 in a speed change control valve 106 is temporarily shifted to the left side via a speed change control mechanism 112, and ports 172a and 172b are interconnected with each other in position between lands 174a and 174b whereby line pressure is fed to an oil passage 160. This line pressure acts on a port 146a of the speed change control valve 106 and gives right-handed force to a spool 148 so that the line pressure rises. With a temporary rise in the line pressure, oil is quickly fed to a driven pulley cylinder chamber 56 whereby rapid speed change takes place, thus speed change responsiveness is improved and any possible slips in a V-belt are checked. |
