DELIVERY CAPACITY ADJUSTING DEVICE FOR VARIABLE CAPACITY HYDRAULIC MACHINE

摘要

PROBLEM TO BE SOLVED: To provide a delivery capacity adjusting device with simple structure for making the suction horsepower of a variable displacement pump approximate to a theoretical curve to a large extent compared with a conventional technology.;SOLUTION: A spring force generating means 1 is constituted of one spring 129, and a piston means is constituted of small-diameter pistons 110, 112 and 116 different in lengths. Depending on a change in the drive pressure of the variable displacement pump, a plurality of pistons against spring forces perform stroke movement while pushing a pilot piston 137. When a piston having the minimal stroke amount is stopped by means of its regulation part to eliminate the contribution of the stopped engine to the spring force, a pressing force to the pilot piston is reduced by an amount of the contribution. Therefore, characteristics of the pressing force are changed for every stroke amount reach of each piston, so that a P-Q characteristic approximates to a theoretical hyperbolic curve.;COPYRIGHT: (C)2005,JPO&NCIPI