HYDRAULIC PRESSURE CONTROL DEVICE

摘要

This hydraulic pressure control device (1) is provided with a directional valve (26), an operated valve (36), a first back pressure output mechanism (42), and a second shuttle valve (41). Upon operation of an operating lever (37), the operated valve (36)outputs a first output pressure (P01) commensurate to the operational input, and once a predetermined operating level is satisfied, the first back pressure output mechanism (42) outputs a first back pressure (Pb1). The first output pressure (P01) is input as a first pilot pressure (P1) to the directional valve (26), and the first back pressure (Pb1) is input as a second pilot pressure (P2) to the directional valve (26). The directional valve (26) is designed to supply a cylinder (7) for a boom with hydraulic pressure commensurate to the pressure differential of the first and second pilot pressures (P1, P2).