To prevent overload condition in a hydrostatic power transmission, and enable effective use of power by letting a hydraulic pump itself prevent such overload condition.
In a hydrostatic power transmission in which a hydraulic motor is connected through piping to a variable displacement hydraulic pump 1 driven and rotated by an engine or the like and the displacement of the variable displacement hydraulic pump 1 is varied by manually operating a control member 15 connected to a tilting shaft 8 for a swash plate 9 and thereby rotating the tilting shaft 8, the tilting shaft 8 and the control member 15 are fixed each other through an elastic piece 15. As the discharge pressure of the variable displacement hydraulic pump 1 increases, a tilting moment is caused at the swash plate 9 in such a direction as to decrease its tilting angle, and the pump displacement is decreased irrespective of the operating position of the control member 15.
OSHINO TSUTOMU