| 摘要 |
PURPOSE:To prevent speed change shocks of an automatic speed change gear with a simple hydraulic circuit by feeding a hydraulic oil by use of a hydraulic solenoid valve and a shock-preventing valve at the time of shifting of each servo and feeding a line pressure by a shift valve on completion of the shifting. CONSTITUTION:At the time of shifting, a solenoid valve 300 is opened and closed at a predetermined frequency by an electric control circuit, so that the pressure inside an oil chamber 263 changes and the pressure inside a hydraulic pressure regulating chamber 264 of a shock-preventing valve 260 is regulated. The regulated hydraulic oil is fed to predetermined hydraulic servos 24, 25, 12, 19, and 26 through a 2-3 shift control valve 240, N-D shift control valve 280, and the like and closes the servos gradually. After a predetermined time lapse after the completion of the engagement of gears, the oil passages of the shift valves 240 and 280 are changed over so as to feed a line pressure to the servos 24, 25, 12, 19, and 26. In this condition, the hydraulic pressure from the valve 260 is fed to an oil conduit connected to the hydraulic pressure for obtaining the next shift. |
