摘要 |
<p>A displacement controlling device for a variable displacement type hydraulic pump comprising a cylinder (21) for varying the displacement of a variable displacement type hydraulic pump (2), a control valve (26) for controlling the supply and discharge of discharging pressure of the variable displacement type hydraulic pump to and from the cylinder, a fixed displacement type hydraulic pump (3) driven together with the variable displacement type hydraulic pump by the same engine (1), and a throttle valve (18) provided along a discharge line of the fixed displacement type hydraulic pump, wherein the control valve is changed over by virtue of comparison between a differential pressure between the discharge pressure and a loading pressure and a set differential pressure, which is a differential pressure across the throttle valve so as to control the displacement of the variable displacement type hydraulic pump via the cylinder, whereby the differential pressure is made to be a certain value that matches the set differential pressure.</p> |