| 摘要 |
Herein disclosed is a hydraulic control valve which is equipped with two direction change-over valve groups (3,4) individually having traveling change-over valves (D,I), and first and second hydraulic pumps (1,2) corresponding to those direction change-over valve groups (3,4). The traveling section valve (D) of one of the change-over groups is equipped with a communication valve (32). Each section valve has its valve body formed therethrough with signal conduits (14,14') individually extending perpendicular to spool bores. The two traveling section valves (D,I) are formed with annular grooves (142) in spool bores (19,19') positioned to correspond to said signal conduits (14,14'). The individual working machine section valves (B,C,E,J,K) other than the traveling section valves (D,I) are formed with annular grooves (141) in the spool portions corresponding to the signal conduits (14,14') to provide the communications between the upstreams and downstreams of the signal conduits (14,14') only when the spools (19,19') are in their neutral states. If the working machine section valves (B,L,E,J,K) are operated while actuating the traveling section valves (D,I), the signal conduits are shut off in accordance with the movements of the spools to raise the pressures in the operation signal conduits (15). This raised pressure actuates the communication valves (32) so that the discharged oil of the second hydraulic pump (2) may merge through the communication conduits (25,25') of the two direction change-over valve groups (3,4) and may be introduced into the traveling section valves (D,I) short of the oil. |
