| 摘要 |
PURPOSE:To prevent a drop of efficiency at operation in high speed mode by forcibly locking the low speed unit of a differential mechanism when a hydraulic machine type transmission provided with the differential mechanism is operating in high speed mode. CONSTITUTION:If the capacity of a pump motor 7 is decreased by steps during an operation in high speed mode, the rotational speed of an output shaft 19 in relation to the rotational speed of an input shaft 13 is getting higher. However, when this rotational speed reaches the maximum speed range, the capacity of a pump motor 5 drops almost to zero, while the pump motor 7 is operated at its maximum rotational speed, duly causing a drop of mechanism efficiency. Then, if the input output shaft 7a of the pump motor 7 is disconnected from a differential mechanism 4 as well as the input/output shaft 5a of the pump motor 5 is locked, power is transmitted from the input shaft 13 to the output shaft 19 through only a mechanical power transmission system b. |
