| 摘要 |
PURPOSE:To make it possible to restrain a clutch from abruptly changing, by reducing the duty ratio of a duty signal adapted to be applied to a clutch pressure control solenoid valve, by a predetermined rate when the vehicle operating condition is shifted from a start mode into a drive mode. CONSTITUTION:A belt drive type continuously variable transmission 2 is composed of a primary pressure control valve 34 as a speed change control valve, a constant pressure control valve 38, a line pressure control valve 44 and a clutch pressure control valve 52 in a hydraulic circuit, and the valves 34, 44, 52 are controlled by a control section 82 through solenoid valves 42, 50, 58, respectively. The clutch pressure control valve 52 is provided so as to control the clutch pressure of a hydraulic start clutch 62. In this arrangement, if the control section 82 determines that the vehicle operating condition is shifted from a start mode into a drive mode, the duty ratio of a duty signal applied to the clutch pressure control solenoid valve 58 is reduced by a predetermined rate, thereby it is possible to control the clutch pressure with no abrupt change. |
