| 摘要 |
PROBLEM TO BE SOLVED: To provide a structure of a hydraulic-mechanical transmission provided to a working vehicle, in which a movable swash plate of a hydraulic pump in the HST is controlled with the decrease in the volume efficiency of the HST, so as to achieve smooth traveling. SOLUTION: In the hydraulic-mechanical transmission (HMT), a swash plate angle of the HST is offset by a correction valueΔr0 of a tilt angle (HST swash plate angle) of a movable swash plate 22a in a hydraulic pump 22, on the basis of a load applied to the HST21 on the decelerating side, when increasing vehicle speed and on the accelerating side, when reducing vehicle speed. The correction valueΔr0 is determined on the basis of the value of the load, which is estimated from a difference between a rotation speed of an actual output shaft 27 and the rotation speed of an output shaft 27, which is detected in the immediately previous control loop and determined by a shift operating means, such as a main shift operating means 84, whereby the HST swash plate angle is subjected to the feedback control.
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