| 摘要 |
PURPOSE:To prevent generation of a speed change shock, in the case of performing the second speed change judgment during a simultaneous speed change of main and sub speed change units. CONSTITUTION:In the case of executing a simultaneous speed change, a relay valve shuts off between a hydraulic servo of the fourth brake B0 and an accumulator, and oil pressure in the hydraulic servo is controlled by an electric signal. During this simultaneous speed change, in the case of performing the second speed change judgment by a speed change judging means, while a rotational speed detected by rotational speed sensors 56, 58 is monitored, the oil pressure in the hydraulic servo is controlled and returned to a condition before the simultaneous speed change to form a specific speed change stage. At a point of time the rotational speed becomes a preset value, the hydraulic servo of the fourth brake B0 is connected to the accumulator, but an electric signal is fed to a solenoid valve before this time to increase a line pressure regulated by a regulator valve. Decrease of the oil pressure due to connection of the accumulator can be suppressed. |
