[go: up one dir, main page]

US20150017029A1 - Pressure overshooting prevention system for electronic hydraulic pump in hydraulic system - Google Patents

Pressure overshooting prevention system for electronic hydraulic pump in hydraulic system Download PDF

Info

Publication number
US20150017029A1
US20150017029A1 US14/368,430 US201214368430A US2015017029A1 US 20150017029 A1 US20150017029 A1 US 20150017029A1 US 201214368430 A US201214368430 A US 201214368430A US 2015017029 A1 US2015017029 A1 US 2015017029A1
Authority
US
United States
Prior art keywords
pressure
flow rate
command
stall
pressure command
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Abandoned
Application number
US14/368,430
Other languages
English (en)
Inventor
Woo Yong Jung
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
HD Hyundai Infracore Co Ltd
Original Assignee
Doosan Infracore Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Doosan Infracore Co Ltd filed Critical Doosan Infracore Co Ltd
Assigned to DOOSAN INFRACORE CO., LTD. reassignment DOOSAN INFRACORE CO., LTD. ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: JUNG, WOO YONG
Publication of US20150017029A1 publication Critical patent/US20150017029A1/en
Abandoned legal-status Critical Current

Links

Images

Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
    • F04B17/00—Pumps characterised by combination with, or adaptation to, specific driving engines or motors
    • F04B17/03—Pumps characterised by combination with, or adaptation to, specific driving engines or motors driven by electric motors
    • F04B17/04—Pumps characterised by combination with, or adaptation to, specific driving engines or motors driven by electric motors using solenoids
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
    • F04B49/00—Control, e.g. of pump delivery, or pump pressure of, or safety measures for, machines, pumps, or pumping installations, not otherwise provided for, or of interest apart from, groups F04B1/00 - F04B47/00
    • F04B49/02—Stopping, starting, unloading or idling control
    • F04B49/03—Stopping, starting, unloading or idling control by means of valves
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
    • F04B35/00—Piston pumps specially adapted for elastic fluids and characterised by the driving means to their working members, or by combination with, or adaptation to, specific driving engines or motors, not otherwise provided for
    • F04B35/04—Piston pumps specially adapted for elastic fluids and characterised by the driving means to their working members, or by combination with, or adaptation to, specific driving engines or motors, not otherwise provided for the means being electric
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
    • F04B49/00—Control, e.g. of pump delivery, or pump pressure of, or safety measures for, machines, pumps, or pumping installations, not otherwise provided for, or of interest apart from, groups F04B1/00 - F04B47/00
    • F04B49/08—Regulating by delivery pressure
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
    • F04B49/00—Control, e.g. of pump delivery, or pump pressure of, or safety measures for, machines, pumps, or pumping installations, not otherwise provided for, or of interest apart from, groups F04B1/00 - F04B47/00
    • F04B49/10—Other safety measures
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B11/00—Servomotor systems without provision for follow-up action; Circuits therefor
    • F15B11/02—Systems essentially incorporating special features for controlling the speed or actuating force of an output member
    • F15B11/04—Systems essentially incorporating special features for controlling the speed or actuating force of an output member for controlling the speed
    • F15B11/042—Systems essentially incorporating special features for controlling the speed or actuating force of an output member for controlling the speed by means in the feed line, i.e. "meter in"
    • F15B11/0423—Systems essentially incorporating special features for controlling the speed or actuating force of an output member for controlling the speed by means in the feed line, i.e. "meter in" by controlling pump output or bypass, other than to maintain constant speed
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/20—Fluid pressure source, e.g. accumulator or variable axial piston pump
    • F15B2211/205—Systems with pumps
    • F15B2211/2053—Type of pump
    • F15B2211/20546—Type of pump variable capacity
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/20—Fluid pressure source, e.g. accumulator or variable axial piston pump
    • F15B2211/205—Systems with pumps
    • F15B2211/2053—Type of pump
    • F15B2211/20546—Type of pump variable capacity
    • F15B2211/20553—Type of pump variable capacity with pilot circuit, e.g. for controlling a swash plate
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/60—Circuit components or control therefor
    • F15B2211/63—Electronic controllers
    • F15B2211/6303—Electronic controllers using input signals
    • F15B2211/6333—Electronic controllers using input signals representing a state of the pressure source, e.g. swash plate angle
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/60—Circuit components or control therefor
    • F15B2211/665—Methods of control using electronic components
    • F15B2211/6652—Control of the pressure source, e.g. control of the swash plate angle
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/60—Circuit components or control therefor
    • F15B2211/665—Methods of control using electronic components
    • F15B2211/6654—Flow rate control

Definitions

  • the present disclosure relates to a pressure overshooting prevention system for an electronic hydraulic pump in a hydraulic system, and more particularly, to a pressure overshooting prevention system for an electronic hydraulic pump in a hydraulic system, capable of preventing pressure overshooting by controlling a pressure command to an electronic hydraulic pump in a hydraulic system in a state in which an actuator cannot be operated any more.
  • a working fluid is discharged from an electronic hydraulic pump, and the working fluid is on standby at an inlet of a main control valve.
  • a plurality of spools is provided in the main control valve, and a plurality of actuators is connected outside the main control valve.
  • pilot pressure is generated in a flow rate requiring unit such as a joystick and a pedal, and the pilot pressure is provided to the main control valve.
  • a specific spool of the main control valve is opened and closed by the pilot pressure, and the working fluid is provided to the actuator associated with the corresponding spool by the operation of opening and closing the corresponding spool.
  • the actuator is operated.
  • the actuator has a piston rod provided in a cylinder, and the piston rod is operated by pressure of the working fluid in a direction in which the piston rod is extended or retracted.
  • the piston rod may reach an end point at which the piston rod cannot be extended any more, or the piston rod cannot be extended or retracted any more due to large external loads.
  • the situation in which physical resistance is applied to the piston rod so that the piston rod cannot be operated may be defined as a stall.
  • a safety device is provided in the hydraulic system, and as the safety device, for example, there is a variable relief valve that is opened to discharge the working fluid when pressure is set to be higher than allowable pressure.
  • hydraulic system that has a main control valve in which a center bypass line is blocked, and a pressure control type electronic hydraulic pump, and there is a technology that reduces a flow rate by decreasing a swash plate angle of the electronic hydraulic pump to a minimum level when the actuator stalls in this hydraulic system.
  • the working fluid is constantly discharged from the electronic hydraulic pump even in a case in which the hydraulic pressure is being stabilized while being decreased to safe pressure by opening the variable relief valve or adjusting the swash plate angle to a minimum level, and in this case, a pressure peak instantaneously occurs due to the flow rate of the discharged working fluid.
  • the pressure peak weakens durability of the hydraulic system.
  • FIG. 1 is a view for explaining a hydraulic system having a pressure control type electronic hydraulic pump.
  • the hydraulic system includes a flow rate requiring unit 10 which is configured as a joystick, a pedal, or the like, an electronic hydraulic pump 50 which discharges a working fluid, and a main control valve 60 which provides the working fluid to an actuator 70 by opening and closing a spool.
  • a flow rate requiring unit 10 which is configured as a joystick, a pedal, or the like
  • an electronic hydraulic pump 50 which discharges a working fluid
  • a main control valve 60 which provides the working fluid to an actuator 70 by opening and closing a spool.
  • pilot pressure is generated by the flow rate requiring unit 10 , and the pilot pressure is provided to the main control valve 60 .
  • the main control valve 60 has a plurality of spools therein, the spools are operated by the pilot pressure, and the main control valve 60 allows the working fluid to pass therethrough when the spools are opened, and shuts off a flow of the working fluid when the spools are closed.
  • the actuator 70 has a piston rod provided in a cylinder, and a piston head side and a tail side are connected with the main control valve 60 , and supplied with the working fluid.
  • the piston rod is extended or retracted in accordance with a direction in which the working fluid is supplied, and a direction in which the working fluid is discharged.
  • a stall occurs in a case in which the piston rod cannot be moved any more. That is, the actuator 70 stalls in a case in which the piston rod cannot be moved any more.
  • the electronic hydraulic pump 50 discharges the working fluid in which hydraulic pressure is formed.
  • the hydraulic pressure of the working fluid may be determined by a swash plate angle. For example, assuming that the shaft of the electronic hydraulic pump 50 is rotated with the same number of revolutions, high pressure is formed and the flow rate is increased as the swash plate angle is increased, and low pressure is formed and the flow rate is decreased as the swash plate angle is decreased. Meanwhile, when the swash plate angle is changed, a period of time is required to set a desired swash plate angle because there are physical dynamic characteristics.
  • the swash plate angle of the electronic hydraulic pump 50 is adjusted by a pump regulator 40 , and the pump regulator 40 is operated by an electronic proportional control valve 30 .
  • the electronic proportional control valve 30 is operated by a pressure command, and the pressure command is provided from a pump control unit 20 .
  • the pump control unit 20 receives a pressure value of pilot pressure formed by the flow rate requiring unit 10 , and a swash plate angle value of the electronic hydraulic pump 50 , and calculates the pressure command.
  • the pressure command from the pump control unit 20 is applied to the electronic proportional control valve 30 as an electrical signal, the electronic proportional control valve 30 operates the pump regulator 40 , and the pump regulator 40 adjusts the swash plate angle of the electronic hydraulic pump 50 so as to discharge the working fluid at a flow rate that corresponds to a required flow rate.
  • allowable pressure may be set in the hydraulic system, and in a case in which pressure, which is higher than the allowable pressure, is formed, the variable relief valve 80 is opened to allow the working fluid to maintain the set pressure.
  • the allowable pressure set in the hydraulic system is variable, and may be varied and set depending on a capacity of the hydraulic system.
  • FIG. 2 is a view for explaining control logic of the pressure control type electronic hydraulic pump in the hydraulic system in the related art.
  • the pump control unit 20 receives a pressure value of pilot pressure formed by the flow rate requiring unit 10 , and a swash plate angle value of the electronic hydraulic pump 50 , and calculates the pressure command.
  • a pressure value of the pilot pressure may be understood as a required pressure value.
  • the flow rate command generating unit 21 may be the data that has been input by a manufacturer of the hydraulic system in advance. That is, an electric current signal corresponding to the required pressure value is generated, and the electric current signal becomes the flow rate command.
  • the current discharge flow rate can be seen when a value of the swash plate angle of the electronic hydraulic pump 50 is recognized.
  • a flow rate command calculating unit 23 the flow rate command is added (+), the discharge flow rate is subtracted ( ⁇ ), and then a displacement flow rate (Delta Q) is calculated.
  • the displacement flow rate (Delta Q) is converted into the pressure command by the flow rate control unit 24 .
  • the pressure command is used to control the electronic proportional control valve 30 , as described above.
  • FIG. 3 is a view for explaining pressure in control logic of the pressure control type electronic hydraulic pump in the related art, and a mapping line drawing of a pressure command.
  • the flow rate is changed with a delay due to the aforementioned time interval, and an abnormal peak P is generated in a situation in which a stall occurs, and this process will be described with reference to the attached FIG. 4 .
  • FIG. 4 is a line drawing illustrating a variation in flow rate according to variation in time for explaining an example in which a peak is generated at a discharge flow rate by the pressure control type electronic hydraulic pump in the related art.
  • the required flow rate and the required hydraulic pressure are increased from a time point t 0 when manipulating the joystick.
  • the pump pressure command is also increased, and the discharge flow rate of the working fluid of the electronic hydraulic pump 50 is increased.
  • the actuator 70 When a state in which the joystick is constantly manipulated is maintained, the actuator 70 is extended or retracted.
  • a variation in flow rate occurs as the displacement flow rate (delta Q) from the time point t 1 when a stall occurs.
  • the pressure command of the electronic proportional control valve 30 is increased to a time point t 2 when the swash plate angle is completely moved to a minimum level with a gradient a when the pressure is increased.
  • the pressure in the pump regulator 40 is rapidly increased with a gradient b 1 that is greater than the gradient a so as to form a peak p, and thereafter, the pressure is decreased with a gradient b 2 , and depends on the pressure of the electronic proportional control valve 30 .
  • the working fluid is discharged at the flow rate that is substantially discharged from the electronic hydraulic pump 50 , and the flow rate is excessive by an area indicated by a c region in FIG. 4 . Accordingly, there is a problem in that the overshot working fluid degrades durability of the hydraulic system.
  • a technical problem to be resolved by the present disclosure is to provide a pressure overshooting prevention system for an electronic hydraulic pump in a hydraulic system, which more quickly reduces a discharge flow rate of an electronic hydraulic pump when a stall occurs such that the actuator does not receive a working fluid, thereby stabilizing the hydraulic system.
  • a pressure overshooting prevention system for an electronic hydraulic pump in a hydraulic system includes: a flow rate command calculating unit 23 which adds (+) a flow rate command corresponding to required pressure, subtracts ( ⁇ ) a discharge flow rate discharged from an electronic hydraulic pump 50 , and calculates a displacement flow rate (Delta Q); a flow rate control unit 24 which generates a first pressure command corresponding to the displacement flow rate Delta Q; a stall determining unit 114 which determines a stall based on a first rate of change of the flow rate command, and a second rate of change of the discharge flow rate; a flow rate pressure generating unit 115 which generates a working fluid pressure value corresponding to the discharge flow rate; a gradient limiting unit 116 which generates a limit pressure command so as to limit an increasing gradient of the working fluid pressure value; a selecting unit 117 which sets the limit pressure command to a second pressure command when a stall is determined by the stall determining unit
  • the stall determining unit 114 of the pressure overshooting prevention system for an electronic hydraulic pump in a hydraulic system may determine the stall when the second rate of change is greater than the first rate of change.
  • a second pressure command gradient a 2 after a time point t 4 when the stall is determined may be smaller than a first pressure command gradient a 1 before the time point t 4 when the stall is determined.
  • the selecting unit 117 of the pressure overshooting prevention system for an electronic hydraulic pump in a hydraulic system may set a system pressure command to the second pressure command when the stall determining unit 114 determines that the stall is released.
  • the pressure overshooting prevention system for an electronic hydraulic pump in a hydraulic system which is configured as described above, more quickly changes the pressure command which is used to control the electronic hydraulic pump when a stall occurs, such that the swash plate angle in the electronic hydraulic pump may be more quickly moved, thereby remarkably reducing the working fluid flow rate that is overshot in the electronic hydraulic pump. That is, the overshooting working fluid is reduced, thereby improving durability of the hydraulic system.
  • FIG. 1 is a view for explaining a hydraulic system having a pressure control type electronic hydraulic pump.
  • FIG. 2 is a view for explaining control logic of the pressure control type electronic hydraulic pump in the hydraulic system in the related art.
  • FIG. 3 is a view for explaining pressure in control logic of the pressure control type electronic hydraulic pump in the related art, and a mapping line drawing of a pressure command.
  • FIG. 4 is a line drawing illustrating a variation in flow rate according to variation in time for explaining an example in which a peak is generated at a discharge flow rate by the pressure control type electronic hydraulic pump in the related art.
  • FIG. 5 is a view for explaining control logic of a pressure control type electronic hydraulic pump in a pressure overshooting prevention system for an electronic hydraulic pump in a hydraulic system according to an exemplary embodiment of the present disclosure.
  • FIG. 6 is a view for explaining logic of a maximum pressure limiting unit in the pressure overshooting prevention system for an electronic hydraulic pump in a hydraulic system according to the exemplary embodiment of the present disclosure.
  • FIG. 7 is a line drawing illustrating a variation in flow rate according to a variation in time for explaining an example that prevents a peak at a discharge flow rate in the pressure overshooting prevention system for an electronic hydraulic pump in a hydraulic system according to the exemplary embodiment of the present disclosure.
  • a stall means a phenomenon in which an actuator 70 is stopped when a piston rod of the actuator 70 reaches an end point when the piston rod is extended or retracted, or when the piston rod cannot be moved any more by an external load.
  • overshooting means a phenomenon in which a working fluid is discharged from an electronic hydraulic pump 50 for a period of time that is physically delayed due to dynamic characteristics when a pump regulator 40 responds to a pressure command made by an electronic proportional control valve 30 .
  • the attached FIG. 1 is a view for explaining a hydraulic system having the pressure control type electronic hydraulic pump.
  • the attached FIG. 5 is a view for explaining control logic of the pressure control type electronic hydraulic pump in the pressure overshooting prevention system for an electronic hydraulic pump in a hydraulic system according to the exemplary embodiment of the present disclosure.
  • a pump control unit 100 is operated by control logic of an electronic hydraulic pump.
  • the pump control unit 100 controls the electronic hydraulic pump 50 suitably for a required flow rate by adding and subtracting the required flow rate and a flow rate at which the working fluid is discharged from the electronic hydraulic pump 50 .
  • the aforementioned required flow rate is generated by manipulating a flow rate requiring unit 10 .
  • required pressure is generated, and a required flow rate is determined as a set rate by the flow rate command generating unit 21 according to the required pressure.
  • the required flow rate is used to control a flow rate control unit 24 as a required flow rate command.
  • the flow rate control unit 24 controls an electronic proportional control valve 30 as a pressure command corresponding to flow rate control is converted.
  • the aforementioned electronic hydraulic pump 50 may output a value of a swash plate angle, and the swash plate angle value is provided to a discharge flow rate calculating unit 22 so that the current flow rate of the working fluid discharged from the electronic hydraulic pump 50 may be calculated.
  • a flow rate command calculating unit 23 receives the aforementioned flow rate command and information on a discharge flow rate. In the flow rate command calculating unit 23 , when a required command is added (+), and the discharge flow rate is subtracted ( ⁇ ), a displacement flow rate (Delta Q) which indicates whether to change the flow rate to any extent is calculated.
  • the displacement flow rate (Delta Q) is converted into the pressure command by the flow rate control unit 24 .
  • the pressure command is used to control the electronic proportional control valve 30 , as described above.
  • the hydraulic system according to the exemplary embodiment of the present disclosure further includes a minimum pressure setting unit 120 between the flow rate control unit 24 and the electronic proportional control valve 30 .
  • the minimum pressure setting unit 120 receives the pressure command from the maximum pressure limiting unit 110 .
  • the minimum pressure setting unit 120 selects a small pressure command of a first pressure command input by the flow rate control unit 24 and a second pressure command input by the aforementioned maximum pressure limiting unit 110 , and controls the electronic proportional control valve 30 .
  • the aforementioned maximum pressure limiting unit 110 will be described with reference to FIG. 6 .
  • FIG. 6 is a view for explaining logic of a maximum pressure limiting unit in the pressure overshooting prevention system for an electronic hydraulic pump in a hydraulic system according to the exemplary embodiment of the present disclosure.
  • the maximum pressure limiting unit 110 receives a pump discharge flow rate and the flow rate command so as to generate the second pressure command.
  • the second pressure command limits and is generated a gradient a raised pump pressure command in accordance with a map of a gradient limiting unit 116 which allows maximum pressure to be set depending on the current discharge flow rate.
  • the flow rate calculating unit 111 calculates the required flow rate by receiving and adding and subtracting the flow rate command and a value of the pump discharge flow rate.
  • the required flow rate may be varied depending on an amount of manipulation of the flow rate requiring unit 10 , and the required flow rate may be rapidly varied, or slowly varied, and the extent of the variation is calculated by a first flow rate variation calculating unit 112 , and a rate of change of the required flow rate is calculated.
  • a second flow rate variation calculating unit 113 receives a value of the pump discharge flow rate, and calculates a second rate of change of the discharge flow rate of the working fluid that is actually discharged from the electronic hydraulic pump 50 .
  • a stall determining unit 114 compares a first rate of change of the flow rate command with the second rate of change of the discharge flow rate, and determines whether the actuator 70 stalls. That is, when the second rate of change is greater than the first rate of change, a situation in which a stall occurs is determined.
  • the stall state is a state in which the piston rod of the actuator 70 is not moved even though a driver manipulates the joystick, the flow rate command is present, but the actuator 70 does not receive the flow rate of the working fluid, such that a flow path of the hydraulic system is shut off, and the swash plate angle of the electronic hydraulic pump 50 is quickly reduced. That is, the stall state is determined when a variation value with respect to a difference between the flow rate command and the pump discharge flow rate is greater than a set value, and a variation value of the discharge flow rate of the electronic hydraulic pump 50 is smaller than the set value.
  • a working fluid pressure value corresponding to the current pump discharge flow rate is set by the flow rate pressure generating unit 115 depending on the pump discharge flow rate value.
  • the aforementioned working fluid pressure value is increased with a gradient value set by the gradient limiting unit 116 .
  • a selecting unit 117 receives a limit pressure command set from the aforementioned gradient value, and a system pressure command set by the hydraulic system, outputs the limit pressure command when the aforementioned stall determining unit 114 determines the stall, and outputs the system pressure command when there is no stall.
  • the limit pressure command is deselected by the selecting unit 117 , such that the system pressure command is output.
  • the pressure command output from the aforementioned selecting unit 117 is set as the aforementioned second pressure command.
  • the minimum pressure setting unit 120 finally outputs a small pressure command of the first pressure command provided from the flow rate control unit 24 , and the second pressure command provided from the aforementioned selecting unit 117 .
  • the pressure command having the limited gradient is provided to the pressure electronic proportional control valve 30 , the flow rate of the working fluid discharged from the electronic hydraulic pump 50 is more quickly reduced, thereby resolving the problem that the working fluid is overshot.
  • FIG. 7 is a line drawing illustrating a variation in flow rate according to a variation in time for explaining an example that prevents a peak at a discharge flow rate in the pressure overshooting prevention system for an electronic hydraulic pump in a hydraulic system according to the exemplary embodiment of the present disclosure.
  • the actuator 70 When a state in which the joystick is constantly manipulated is maintained, the actuator 70 is extended or retracted.
  • a variation in flow rate occurs as the displacement flow rate (delta Q) from the time point t 1 when a stall occurs.
  • the pressure command of the electronic proportional control valve 30 is varied regarding the pump pressure command.
  • the swash plate angle is varied with the first pressure command gradient a 1 corresponding to the first pressure command, and the swash plate angle of a second pressure command gradient a 2 corresponding to the second pressure command is varied from the time point t 4 when the stall is determined by the stall determining unit 114 .
  • the second pressure command has a limited gradient in comparison with the first pressure command, such that the second pressure command gradient a 2 is formed to be small in comparison with the first pressure command gradient a 1 .
  • the electronic hydraulic pump 50 depends on the pressure command, such that an initial first actual pressure line drawing b 1 depends on the first pressure command gradient a 1 at the time point t 1 when a stall occurs, is reduced as exemplified by a second actual pressure line drawing b 2 immediately after being changed to the second pressure command gradient a 2 , and then is stabilized.
  • the pressure overshooting prevention system reduces the pressure command much earlier, thereby remarkably lowering the flow rate peak p.
  • the time point t 3 when the swash plate angle of the electronic hydraulic pump 50 is completely moved to a minimum level may be advanced, thereby reducing the flow rate c of the working fluid that is discharged while the swash plate angle is moved to a minimum level as a stall occurs.
  • the pressure overshooting prevention system for an electronic hydraulic pump in a hydraulic system finally outputs a small value of output values of the maximum pressure limiting unit 110 and the flow rate control unit 24 as the pressure command, thereby reducing the pressure peak in the stall state.
  • the pressure overshooting prevention system for an electronic hydraulic pump in a hydraulic system more quickly changes the pressure command which is used to control the electronic hydraulic pump 50 when a stall occurs, such that the swash plate angle in the electronic hydraulic pump 50 may be more quickly moved, thereby remarkably reducing the working fluid flow rate c that is overshot in the electronic hydraulic pump 50 . That is, the overshooting working fluid is reduced, thereby improving durability of the hydraulic system.
  • the pressure overshooting prevention system for an electronic hydraulic pump of a hydraulic system quickly reduces the discharge flow rate of the electronic hydraulic pump when a stall occurs so that the actuator cannot be operated, and may be used to improve durability of the hydraulic system.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Control Of Positive-Displacement Pumps (AREA)
  • Fluid-Pressure Circuits (AREA)
  • Reciprocating Pumps (AREA)
US14/368,430 2011-12-27 2012-12-24 Pressure overshooting prevention system for electronic hydraulic pump in hydraulic system Abandoned US20150017029A1 (en)

Applications Claiming Priority (5)

Application Number Priority Date Filing Date Title
KR10-2011-0142928 2011-12-27
KR20110142928 2011-12-27
KR1020120147434A KR101958489B1 (ko) 2011-12-27 2012-12-17 유압시스템의 전자유압펌프의 압력 오버슈팅 방지 시스템
KR10-2012-0147434 2012-12-17
PCT/KR2012/011352 WO2013100509A1 (fr) 2011-12-27 2012-12-24 Système de prévention du dépassement de pression pour pompe hydraulique électronique incluse dans un système hydraulique

Publications (1)

Publication Number Publication Date
US20150017029A1 true US20150017029A1 (en) 2015-01-15

Family

ID=48989491

Family Applications (1)

Application Number Title Priority Date Filing Date
US14/368,430 Abandoned US20150017029A1 (en) 2011-12-27 2012-12-24 Pressure overshooting prevention system for electronic hydraulic pump in hydraulic system

Country Status (7)

Country Link
US (1) US20150017029A1 (fr)
EP (1) EP2801724B1 (fr)
JP (1) JP5890040B2 (fr)
KR (1) KR101958489B1 (fr)
CN (1) CN104011391B (fr)
BR (1) BR112014016103B1 (fr)
WO (1) WO2013100509A1 (fr)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20160363117A1 (en) * 2014-03-20 2016-12-15 Danfoss Power Solutions Inc. Electronic torque and pressure control for load sensing pumps
USRE50263E1 (en) 2014-06-06 2025-01-07 Bj Energy Solutions, Llc Modular hybrid low emissions power for hydrocarbon extraction

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114909280B (zh) * 2022-04-07 2024-05-17 潍柴动力股份有限公司 基于多源信息反馈优化的液压泵控制方法及系统

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5178053A (en) * 1992-02-13 1993-01-12 Johnson Service Company Electronic pilot positioner
US9206798B2 (en) * 2009-12-23 2015-12-08 Doosan Infracore Co., Ltd. Hydraulic pump control apparatus and method of construction machine

Family Cites Families (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH01110884A (ja) * 1987-07-09 1989-04-27 Tokyo Keiki Co Ltd 可変吐出量ポンプの流量圧力制御装置
US4886422A (en) * 1987-07-09 1989-12-12 Tokyo Keiki Company Ltd. Control apparatus of variable delivery pump
JPH0599121A (ja) * 1991-10-09 1993-04-20 Tokimec Inc 可変容量形油圧ポンプによる流量・圧力制御装置
US5758499A (en) * 1995-03-03 1998-06-02 Hitachi Construction Machinery Co., Ltd. Hydraulic control system
JP3926892B2 (ja) * 1997-07-29 2007-06-06 日立建機株式会社 油圧ポンプのカットオフ装置
JP2002195164A (ja) * 2000-12-27 2002-07-10 Tokimec Inc 吐出流量制御装置
JP4096900B2 (ja) * 2004-03-17 2008-06-04 コベルコ建機株式会社 作業機械の油圧制御回路
JP4434159B2 (ja) * 2006-03-02 2010-03-17 コベルコ建機株式会社 作業機械の油圧制御装置
JP2008222353A (ja) * 2007-03-12 2008-09-25 Mitsubishi Electric Corp エレベータドアの安全装置
KR100974275B1 (ko) * 2007-12-17 2010-08-06 볼보 컨스트럭션 이키프먼트 홀딩 스웨덴 에이비 소 선회식 굴삭기의 붐 충격 완화장치 및 그 제어방법
KR101576674B1 (ko) * 2008-12-22 2015-12-11 두산인프라코어 주식회사 중장비에 이용되는 유압 펌프의 유량 제어 장치

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5178053A (en) * 1992-02-13 1993-01-12 Johnson Service Company Electronic pilot positioner
US9206798B2 (en) * 2009-12-23 2015-12-08 Doosan Infracore Co., Ltd. Hydraulic pump control apparatus and method of construction machine

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20160363117A1 (en) * 2014-03-20 2016-12-15 Danfoss Power Solutions Inc. Electronic torque and pressure control for load sensing pumps
US11644027B2 (en) * 2014-03-20 2023-05-09 Danfoss Power Solutions Inc. Electronic torque and pressure control for load sensing pumps
USRE50263E1 (en) 2014-06-06 2025-01-07 Bj Energy Solutions, Llc Modular hybrid low emissions power for hydrocarbon extraction

Also Published As

Publication number Publication date
CN104011391A (zh) 2014-08-27
JP2015507717A (ja) 2015-03-12
WO2013100509A1 (fr) 2013-07-04
EP2801724A1 (fr) 2014-11-12
KR101958489B1 (ko) 2019-03-14
EP2801724B1 (fr) 2017-03-01
BR112014016103A2 (pt) 2017-06-13
CN104011391B (zh) 2016-02-03
BR112014016103A8 (pt) 2017-07-04
BR112014016103B1 (pt) 2021-04-27
JP5890040B2 (ja) 2016-03-22
KR20130075659A (ko) 2013-07-05
EP2801724A4 (fr) 2015-12-02

Similar Documents

Publication Publication Date Title
US9546468B2 (en) Hydraulic system of construction machine
EP3306112B1 (fr) Dispositif de commande hydraulique d'engin de chantier
US10344458B2 (en) Hydraulic Drive System for work machine
KR101094083B1 (ko) 건설기계의 과부하 방지장치
US10563377B2 (en) Hydraulic pump control system of hydraulic working machine
CN105392999B (zh) 负载传感控制回路
US8726649B2 (en) Controller and work machine provided therewith
JP2009293369A (ja) 複数の可変容量型油圧ポンプトルク制御システム及びその制御方法
EP3305994B1 (fr) Système de commande pour machines de construction et procédé de commande pour machines de construction
US9765503B2 (en) Hydraulic control system for construction machinery
US9644651B2 (en) Method for controlling hydraulic system of construction machinery
US20150017029A1 (en) Pressure overshooting prevention system for electronic hydraulic pump in hydraulic system
WO2018230642A1 (fr) Système hydraulique
EP2937474A2 (fr) Système hydraulique pour équipement de construction
EP3587674B1 (fr) Système de commande d'engin de chantier et procédé de commande d'engin de chantier
EP2811172B1 (fr) Assemblage de soupape hydraulique
US7373869B2 (en) Hydraulic system with mechanism for relieving pressure trapped in an actuator
KR102054519B1 (ko) 건설기계의 유압시스템
CN110741168B (zh) 油压系统
KR20120086062A (ko) 건설기계의 유압시스템
JP2010031978A (ja) 油圧ショベルの油圧制御回路
JP2015137474A (ja) 作業車両
JP5946184B2 (ja) 作業機械の油圧駆動装置
JP2000310205A (ja) 油圧制御装置
CN111373160B (zh) 油压系统

Legal Events

Date Code Title Description
AS Assignment

Owner name: DOOSAN INFRACORE CO., LTD., KOREA, REPUBLIC OF

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:JUNG, WOO YONG;REEL/FRAME:033219/0533

Effective date: 20140624

STCB Information on status: application discontinuation

Free format text: ABANDONED -- FAILURE TO RESPOND TO AN OFFICE ACTION