Multiple pressure compensated flow control valve device of parallel connection used with fixed displacement pump
AssigneeNisshin Sangyo Co., Ltd.
InventorToshinari Sumiyoshi
Life of this patent
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Abstract
A multiple control valve device for connection in parallel between a single fixed displacement pump and one or more oil actuators to control operation of all or a number of the actuators simultaneously. The pump can supply sufficient oil at an optimum pressure which is the highest loading pressure required among the working actuators. At the same time the desired controlled oil flow rate can be held to the desired value for each working actuator by this device. Also this valve device has stepless speed changing control, provides a self-depressing function of pump pressure loading, and can also have the function that a pressure rise or a pressure variation in the actuators can be treated automatically.
Claims2
A control valve device for contolling the flow of pressure liquid to a plurality of hydraulic actuators from a single hydraulic pump, each actuator having a supply line and a return line and the pump having a supply line, and there being a storage tank to which there is a return line and from which the pump draws liquid, said control valve device comprising a plurality of directional valve units each having a directional valve adapted to be connected in parallel between the pump supply line and the respective supply and return lines of the actuators and between the respective supply and return lines of the actuators and the return line, a plurality of first pressure compensating valves, one coupled to each directional and having means for adjusting the opening thereof in response to the pressure difference across the corresponding directional valve, a second pressure compensating valve unit having a single second pressure compensating valve therein adapted to be coupled between the pump supply line and the return line for bypassing said directional valves, pilot pressure sensing means coupled between each directional valve and said second pressure compensating valve for conveying liquid under the pressure in the directional valve to said second pressure compensating valve for adjusting the position of said second pressure compensating valve, check valves in said pilot pressure sensing means associated with each directional valve whereby only the liquid under pressure in the highest pressure directional valve is transmitted to said second pressure compensating valve, a pressure compensated leak valve coupled to said pilot pressure sensing means for bleeding a slight amount of liquid under pressure from said pilot pressure sensing means at all times said leak valve comprising valve means for passing less fluid the greater the pilot pressure, a plurality of third pressure compensating valves, one coupled to each directional valve and adapted to be coupled to said return line and having means for adjusting the opening thereof in response to the pressure difference across the corresponding directional valve, and switching cylinders adapted to be coupled to said pump supply line and operably coupled with said third pressure valves for normally urging said third pressure valves to close and for being disconnected from said third pressure valves when the pressure in the pump supply line rises above a predetermined value.
A control valve device for controlling the flow of pressure liquid to a plurality of hydraulic actuators from a single hydraulic pump, each actuator having a supply line and a return line and the pump having a supply line, and there being a storage tank to which there is a return line and from which the pump draws liquid, said control valve device comprising a plurality of directional valve units each having a directional valve adapted to be connected in parallel between the pump supply line and the respective supply and return lines of the actuators and between the respective supply and return lines of the actuators and the return line, a plurality of first pressure compensating valves, one coupled to each directional valve and having means for adjusting the opening thereof in response to the pressure difference across the corresponding directional valve, a second pressure compensating valve unit having a single second pressure compensating valve therein adapted to be coupled between the pump supply line and the return line for bypassing said directional valves, pilot pressure sensing means coupled between each directional valve and said second pressure compensating valve for conveying liquid under the pressure in the directional valve to said second pressure compensating valve for adjusting the position of said second pressure compensating valve, check valves in said pilot pressure sensing means associated with each directional valve whereby only the liquid under pressure in the highest pressure directional valve is transmitted to said second pressure compensating valve, and a pressure compensated leak valve having a cylinder therein with an outlet therefrom to said return line, a spring loaded hollow piston slidable in said cylinder at a point spaced from said oulet and having a leak bore extending longitudinally therethrough, said leak valve further having a lateral passage opening into said cylinder from said pilot pressure sensing means, and said piston having a lateral passage opening into the hollow thereof and cooperating with said first mentioned lateral passage for opening and closing said first mentioned lateral passage during movement of said piston against said spring loading, whereby a slight amount of liquid is bled under pressure from said pilot pressure sensing means at all times and said leak valve passing less fluid the greater the pilot pressure.
Dependencies are inferred from the claim text.