| 摘要 |
PURPOSE:To switch a speed stage without interrupting the acceleration or deceleration of a vehicle by switching the speed stage when the actual speed ratio is within a specific range and satisfies the speed ratio at a point within a slight value of the relative revolving speed between a clutch and the plate of a disk. CONSTITUTION:This hydrostatic-mechanical transmission is provided with an input shaft 23 connected to the output shaft 22 of an engine 21, a mechanical transmission section 24 having a speed change gear of forward three speeds and reverse three speeds, a hydrostatic transmission section 25 having a hydraulic pump and motor, and a differential section 27 selectively connecting an output shaft 26 to one of the transmission sections 24, 25 to drive it. At the time of switching the speed stage, the speed stage is switched by a controller 74 when the actual speed ratio (e) satisfies the equation ¦Eo¦>¦e¦>¦E1¦, where Eo is the speed ratio at the switching point from an optional speed stage to a speed stage having a faster absolute speed, and E1 is the speed ratio at a point within a slight value of the relative revolving speed between a clutch and the plate of a disk near the speed ratio Eo. |
