| 摘要 |
An overtop position is to be established in a hydrostatic type continuously variable transmission, and an increase of the maximum speed and the maintenance of power performance are to be made compatible with each other. In a hydrostatic type continuously variable transmission, the angle of inclination of a movable swash plate is controlled in such a manner that a target Ne is calculated from both RC (riding condition) and throttle valve opening, then the target Ne thus calculated is compared with an actual Ne to determine a rotational direction and DUTY of a control motor. The operation of the control motor is controlled in accordance with the thus-determined data and angle information on the angle of the movable swash plate provided from an angle sensor. In constant speed vehicular traveling, the change gear ratio is set at TOP ratio and a shift is made to OVERTOP when predetermined overtop control conditions ((1) the current change gear ratio should be at TOP position, (2) the degree opening of a throttle valve should exceed a threshold value determined according to a vehicular speed, and (3) the engine speed should exceed a preset value) are satisfied, thereby increasing the maximum vehicle speed. |
