PURPOSE: To reduce change-over shocks of a transmission so as to obtain smooth drive by providing a solenoid selector valve at each of speed stages, and by storing in memory a delay time between an turn-off time of a solenoid selector value which is engaged at present, and a turn-on time of a solenoid selector valve to be engaged at the next time in accordance with a temperature of hydraulic oil.
CONSTITUTION: A transmission incorporates a solenoid selector valve 1 and a clutch cylinder at each of speed stages. By the way, the solenoid selector valve 1 is controlled by an electronic controller 6 in accordance with detection signals from a temperature sensor 3 for a hydraulic circuit, a rotational speed sensor 4 for the output shaft of the transmission, and a throttle sensor 5 for an engine throttle shaft. In this case, the electronic controller 6 incorporates a relation map 8 which indicates the relationship between the temperature of hydraulic oil and the delay time in the time of speed shift, in addition to a schedule map 7. Further, a delay circuit 9 generates an instruction for turning off the solenoid selector valve 1 which is engaged at present and for tuning on a solenoid valve 1 to be engaged at the next time in accordance with a delay time. Thereafter, a drive circuit 10 drives the solenoid selector valve 1 in accordance the instruction.
YAMADA YOSHIAKI
YOKOMORI TAKESHI
Next Patent: JPS6159493