HYDRAULIC CONTROL SYSTEM FOR LOAD-SENSING CONTROLLED SUPPLY OF HYDRAULIC FLUID FOR PREFERABLY SEVERAL HYDRAULIC CONSUMERS

摘要

A hydraulic control arrangement which is provided for the demand-feed-regulated supply of pressure medium to preferably a plurality of hydraulic consumers by proportionally adjustable directional valves. There are hydraulic pumps by which pressure medium can be conveyed in a quantity corresponding to the demand into a common inflow line leading to the directional valves. A first demand-feed regulator is assigned to the first hydraulic pump and a second demand-feed regulator to the second hydraulic pump. The two demand-feed regulators are capable of being acted upon, with the effect of increasing the pressure medium quantity discharged into the inflow line by the corresponding hydraulic pump, by a spring and, on a first active surface, by the pressure in a load-signaling line and, with the effect of reducing the pressure medium quantity discharged into the inflow line by the corresponding hydraulic pump, on a second active surface, by a pump pressure. Moreover, a nonreturn valve opening toward the inflow line is arranged between the first hydraulic pump and said inflow line. Either both hydraulic pumps or only the second hydraulic pump conveys pressure medium to the inflow line. In order to be more flexible here, a nonreturn valve opening toward the inflow line is also arranged between the second hydraulic pump and the latter. There are also members by which action of force on the demand-feed regulators can be changed that the hydraulic consumers can be supplied with pressure medium both solely by the first hydraulic pump and solely by the second hydraulic pump.