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AssigneeParker-Hannifin Corporation
InventorsRichard H. Woodring, Paul K. Houtman, Thomas A. Kowalski, Charles H. Whitmore
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An electronic control system for pressure and flow control of variable displacement pumps consists of a closed loop system of operational amplifiers which provide continuous control of the volume modifying element in the pump. In a variable displacement vane pump application a command flow control signal and a feedback signal representative of the position of the adjustable cam ring in the pump are applied to an integrating amplifier to develop a signal for application to an electro-hydraulic valve in the pressure compensating portion of the pump. A command pressure signal is compared with the control signal to limit the latter to a level, thereby providing pressure control for the pump. Slip compensation is effected in the control system by utilizing a portion of the control signal to provide proportional modification of the command signal.
A control system for a variable displacement pump having a displacement controlling element moveable to various positions to vary pump output flow in response to urging of a fluid actuator, comprising a pressure compensator for developing a fluid pressure signal, said compensator being coupled to said fluid actuator as the sole element for control thereof, said compensator thereby being operative to control outlet fluid from said pump as a function of said fluid pressure signal, and electrical system means for modifying the fluid pressure signal developed in said compensator to provide both flow and pressure control of outlet fluid of said pump, said electrical system having flow and pressure command signals in electrical format and an electro-hydraulic valve for controlling fluid pressure in said compensator, said electrohydraulic valve being responsive to a combination of flow and pressure command signals.
A system for controlling outlet flow of a variable displacement pump pressure compensator fluid responsive device for adjustment of outlet flow, comprising
A compensator for a variable displacement pump having an adjustable flow controlling element therein, comprising a closed loop position control system for positioning said adjustable element in response to an electrical signal derived from an input command signal representative of a desired level of flow output and a feedback signal representative of actual flow output, and means for developing a pressure command level signal for application to said control system to limit said electrical signal therein, thereby providing flow and pressure control for said pump.
A compensator system for a variable displacement pump, comprising
A pump, comprising
Dependencies are inferred from the claim text.