Load responsive system pump controls
OwnerTadeusz Budzichinventor
Life of this patent
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Abstract
A load responsive fluid power control system using servo type flow control valves and fluid motors supplied by a variable displacement pump. The pump displacement is regulated by a control valve in response to the motor load pressure to vary the pump displacement to maintain a constant preselectable ratio between the pump outlet pressure and motor load pressure and to vary the pressure differential between pump outlet pressure and motor load pressure with variation in magnitude of the load. The pump control also limits maximum and minimum system pressures.
Claims36
A fluid power and control system comprising a fluid pump, a fluid motor driving a load, and valve means interposed between said pump and said motor to control said load, flow changing means operable to vary fluid flow delivered from said pump to said fluid system to vary pressure in said fluid system, first control means having means operable to limit through said flow changing means maximum pressure of said system to a fixed predetermined level, second control means having means operable to limit through said flow changing means minimum pressure of said system to a fixed predetermined level, control signal generating means to generate a control signal proportional to magnitude of said load, and third control means responsive to said control signal having means operable through said flow changing means to maintain a preselectable relatively constant ratio between pressure of said fluid system and pressure necessary to support said load and to vary pressure differential between pressure of said fluid system and pressure necessary to support said load with variation in magnitude of said load.
A fluid power and control system comprising a fluid pump, plurality of fluid motors driving loads, and valve means interposed between said pump and each of said motors to control each load, flow changing means operable to vary fluid flow delivered from said pump to said fluid system to vary pressure in said fluid system, first control means having means operable to limit through said flow changing means maximum pressure of said system to a fixed predetermined level, second control means having means operable to limit through said flow changing means minimum pressure of said system to a fixed predetermined level, control signal generating means to generate a control signal proportional to magnitude of each load, control signal phasing means operable to receive all of said control signals and to pass only the highest signal from the highest system load, and third control means responsive to said highest control signal having means operable through said flow changing means to maintain a preselectable relatively constant ratio between pressure of said fluid system and pressure necessary to support said highest system load and to vary pressure differential between pressure of said fluid system and pressure necessary to support said highest load with variation in the magnitude of said highest load.
A fluid power and control system comprising a fluid pump, at least one fluid motor having a fluid inlet chamber and a fluid outlet chamber driving a load, and servo valve means interposed between said pump and said motor to control said load, flow changing means operable to vary fluid flow delivered from said pump to said fluid system to vary pressure in said fluid system, first control means responsive to pressure in said system operable to limit through said flow changing means maximum pressure in said system, second control means responsive to pressure in said system operable to limit through said flow changing means minimum pressure of said system to a fixed predetermined level, control signal generating means having load pressure sensing means operable to transmit load pressure signal and third control means having fluid control valve means, said fluid control valve means having means responsive to said load pressure signal and said system pressure and operable through said flow changing means to maintain a preselectable relatively constant ratio between pressure of said fluid system and pressure necessary to support said load and to vary pressure differential between pressure of said fluid system and pressure necessary to support said load with variation in magnitude of said load.
A fluid power and control system comprising a fluid pump and a plurality of fluid motors driving loads, servo valve means interposed between said pump and each of said motors, flow changing means operable to vary flow delivered from said pump to said fluid system to vary pressure in said fluid system, control signal generating means operable to generate an electrical signal proportional to magnitude of each of said loads, amplifying means to amplify each of said electrical signals by a ratio as determined by characteristics of each of said servo valve means, control signal phasing means operable to receive all of said amplified control signals from said plurality of motors controlling loads and to pass only the highest of all of all of said signals, first control means having means operable to limit through said flow changing means maximum pressure of said system to a fixed predetermined level, second control means having means operable to limit through said flow changing means minimum pressure of said system to a fixed predetermined level and third control means responsive to said highest control signal transmitted from said control signal phasing means operable through said flow changing means to maintain a preselectable relatively constant ratio between pressure of said fluid system and pressure necessary to support load transmitting said highest control signal.
A fluid power and control system comprising a fluid pump, first plurality of fluid motors driving loads, servo valve means interposed between said pump and each of said motors, second plurality of fluid motors driving loads, direction control valve means interposed between said pump and each of said motors, flow changing means operable to vary fluid flow delivered from said pump to said fluid system to vary pressure in said fluid system, first control means having first valve means responsive to pressure in said system operable to limit through said flow changing means maximum pressure of said system to a fixed predetermined level, second control means responsive to pressure in said system operable to limit through said flow changing means minimum pressure of said system to a fixed predetermined level, first control signal generating means having load pressure sensing means operable to transmit load pressure signals from loads controlled by said servo valve means, first control signal phasing means operable to receive all of said load pressure control signals from said first control signal generating means and to pass only the highest load pressure signal from the highest load, highest control signal amplifying means to amplify said highest signal, second control signal generating means having load pressure sensing means operable to transmit load pressure signals from loads controlled by said direction control valve means, second control signal phasing means operable to receive all of said load pressure control signals from said second control signal generating means and to pass only highest load pressure signal from the highest load, third control means having second valve means, said second valve means having first means responsive to said amplified highest load pressure signal from said first control signal generating means operable through said flow changing means to vary pressure differential between pressure of said fluid system and pressure necessary to support the highest load from said first plurality of fluid motors in proportion to magnitude of said highest load when said amplified highest load pressure signal from said first control signal generating means is higher than said highest load pressure signal from said second control signal generating means, said second control valve means having second means reponsive to said highest load pressure signal from said second control signal generating means operable through said flow changing means to maintain a relatively constant pressure differential between pressure of said fluid system and pressure necessary to support the highest load from said second plurality of fluid motors when said highest load pressure signal from said second control signal generating means is higher than said amplified highest load pressure signal from said first control signal generating means, and deactivating means to deactivate said third control valve means when said first control means limits said maximum pressure of said system.
A fluid power and control system comprising a fluid pump and first plurality of fluid motors driving loads, servo valve means interposed between said pump and each of said motors, second plurality of fluid motors driving loads, direction control valve means interposed between said pump and each of said motors, flow changing means operable to vary fluid flow delivered from said pump to said fluid system to vary pressure in said fluid system, first control means operable to limit through said flow changing means maximum pressure of said system to a fixed predetermined level, second control means operable to limit through said flow changing means minimum pressure of said system to a fixed predetermined level, first control signal generating means operable to generate electrical signals proportional to magnitude of each load driven by said first plurality of fluid motors, first amplifying means to amplify each of said electrical signals by a fixed predetermined ratio preselectable for each load, second control signal generating means operable to generate an electrical signal higher by a constant preselectable value than a signal proportional to magnitude of each load driven by said second plurality of fluid motors, second amplifying means to amplify each of said electrical signals by a fixed ratio for each load lower than amplification ratio of said first amplifying means, control signal phasing means operable to receive all of said amplified control signals from said first and second signal generating means and to pass only the highest of all of said signals, and third control means responsive to said highest electrical load signal, said third control means including a transducer means having means to convert said highest electrical load signal into control pressure signal, fluid control valve means responsive to said control pressure signal and operable to divert fluid flow and pressure, from said pump to an actuating means of said flow changing means to vary flow of said pump to control pressure of said system proportional to the magnitude of said highest electrical load signal, to vary pressure differential between system pressure and pressure necessary to sustain highest load driven by said first plurality of fluid motors in proportion to magnitude of said highest load when highest amplified signal is transmitted from said first control signal generating means, and to maintain a relatively constant pressure differential between system pressure and pressure necessary to sustain highest load driven by said second plurality of fluid motors when highest amplified signal is transmitted from said second control signal generating means.
Dependencies are inferred from the claim text.