| 摘要 |
<p>A pump capacity control device and a valve device, wherein a fixed restriction (12) is provided in a delivery path (11) for a fixed pump (11) drivingly rotated by an engine (9) which also drivingly rotates a hydraulic pump (1), a pressure difference detection valve (31) which detects a pressure difference across the fixed restriction (12) and outputs a pressure lower by a specified value than that pressure difference is provided to the fixed restriction (12), an output of the pressure difference detection valve (31) is guided as a signal pressure to a pressure receiving part (5c) of a load sensing valve (5), and a target pressure difference is set, whereby a pressure linked to an engine rotation speed can be used as a set pressure difference of the load sensing valve, the structure of the load sensing valve is avoided from being complicated, and the capacity of the hydraulic pump is reduced in an idle rotation area where the amount of working is small so as to increase a controllability for fine operation and reduce a fuel consumption. <IMAGE></p> |
