| 摘要 |
PURPOSE:To reduce shift shock based on the speed change difference among the respective speed change stages of an auxiliary speed change part by lowering the maximum value of the voltage for controlling a solenoid proportional control valve as the shift-up of an auxiliary speed change part is performed, thus setting the maximum value of oil pressure acting upon the hydraulic clutch of a main speed change part low. CONSTITUTION:When speed change to the fourth ahead gear speed is performed, a hydraulic clutch CM is engaged to change an auxiliary speed change part 3 to the medium speed as well as the voltage based on a control means rises slowly in comparison to the voltage rise at the time of the auxiliary speed change part 3 being at low speed, and oil pressure controlled by a solenoid proportional control valve S1 on the basis of the voltage rises at the slower pressure-up speed compared to the case of low speed. A hydraulic clutch C1 is then engaged by the oil pressure so as to change a main speed change part 2 to the first gear speed. Accordingly, the clutch C1 of the main speed change part 2 is engaged even more slowly accompanied by the shift-up of the auxiliary speed change part 3, thus reducing shift shock caused by the speed change ratio difference among the respective speed change stages of the auxiliary speed change part 3. |
