| 摘要 |
PURPOSE: To shift a gear to advance or retreat without provided with a starting device nor a normal/reverse turn switching device and at the same time automatically hold it stably at the nondriven state in which output of an output shaft is zero. CONSTITUTION: A CVT 11 and a planetary gear are combined with each other so as to output in the normal/reverse turning direction from an output shaft with a neutral position sandwiched between them. Oil pressures of a hydraulic servos 32, 33 are controlled by a control means 54 and when axial tension difference between the primary pulley and the secondary pulley 9 is produced, the CVT 11 changes speed in compliance with a torque transmission direction and the normal/reverse turning direction. When the axial tensions of the both pulleys 7, 9 are controlled to become equal to each other, the CVT 11 is self converged so that the output shaft becomes in the nondriven state and held stably at the neutral position. |
