Classifications

• • 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
  • F15B11/16—Servomotor systems without provision for follow-up action; Circuits therefor with two or more servomotors
  • F15B11/161—Servomotor systems without provision for follow-up action; Circuits therefor with two or more servomotors with sensing of servomotor demand or load
  • F15B11/165—Servomotor systems without provision for follow-up action; Circuits therefor with two or more servomotors with sensing of servomotor demand or load for adjusting the pump output or bypass in response to demand
• • 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
  • F04B49/06—Control using electricity
• • 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
  • F04B49/06—Control using electricity
  • F04B49/065—Control using electricity and making use of computers
• • 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
  • F04B2201/00—Pump parameters
  • F04B2201/12—Parameters of driving or driven means
  • F04B2201/1204—Position of a rotating inclined plate
  • F04B2201/12041—Angular position
• • 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
  • F04B2201/00—Pump parameters
  • F04B2201/12—Parameters of driving or driven means
  • F04B2201/1205—Position of a non-rotating inclined plate
  • F04B2201/12051—Angular position
• • 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
  • F04B2203/00—Motor parameters
  • F04B2203/06—Motor parameters of internal combustion engines
• • 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
  • F04B2203/00—Motor parameters
  • F04B2203/06—Motor parameters of internal combustion engines
  • F04B2203/0603—Torque
• • 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
  • F04B2205/00—Fluid parameters
  • F04B2205/05—Pressure after the pump outlet
• • 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
  • F04B2205/00—Fluid parameters
  • F04B2205/09—Flow through the pump
• • 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
  • F15B2211/20507—Type of prime mover
  • F15B2211/20523—Internal combustion engine
• • 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
  • F15B2211/255—Flow control functions
• • 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
  • F15B2211/30—Directional control
  • F15B2211/305—Directional control characterised by the type of valves
  • F15B2211/30525—Directional control valves, e.g. 4/3-directional control valve
• • 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
  • F15B2211/30—Directional control
  • F15B2211/305—Directional control characterised by the type of valves
  • F15B2211/3056—Assemblies of multiple valves
• • 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
  • F15B2211/30—Directional control
  • F15B2211/31—Directional control characterised by the positions of the valve element
  • F15B2211/3105—Neutral or centre positions
  • F15B2211/3116—Neutral or centre positions the pump port being open in the centre position, e.g. so-called open centre
• • 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
  • F15B2211/30—Directional control
  • F15B2211/315—Directional control characterised by the connections of the valve or valves in the circuit
  • F15B2211/3157—Directional control characterised by the connections of the valve or valves in the circuit being connected to a pressure source, an output member and a return line
  • F15B2211/31576—Directional control characterised by the connections of the valve or valves in the circuit being connected to a pressure source, an output member and a return line having a single pressure source and a single output member
• • 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
  • F15B2211/50—Pressure control
  • F15B2211/505—Pressure control characterised by the type of pressure control means
  • F15B2211/50509—Pressure control characterised by the type of pressure control means the pressure control means controlling a pressure upstream of the pressure control means
  • F15B2211/50536—Pressure control characterised by the type of pressure control means the pressure control means controlling a pressure upstream of the pressure control means using unloading valves controlling the supply pressure by diverting fluid to the return line
• • 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
  • F15B2211/6306—Electronic controllers using input signals representing a pressure
  • F15B2211/6309—Electronic controllers using input signals representing a pressure the pressure being a pressure source supply pressure
• • 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
  • F15B2211/6306—Electronic controllers using input signals representing a pressure
  • F15B2211/6316—Electronic controllers using input signals representing a pressure the pressure being a pilot pressure
• • 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
  • F15B2211/635—Circuits providing pilot pressure to pilot pressure-controlled fluid circuit elements
  • F15B2211/6355—Circuits providing pilot pressure to pilot pressure-controlled fluid circuit elements having valve means
• • 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
  • F15B2211/6651—Control of the prime mover, e.g. control of the output torque or rotational 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
  • F15B2211/60—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
  • F15B2211/70—Output members, e.g. hydraulic motors or cylinders or control therefor
  • F15B2211/71—Multiple output members, e.g. multiple hydraulic motors or cylinders

Definitions

• the present invention relates to an engine provided in a working machine such as a hydraulic excavator and having a fuel injection control device capable of controlling a governor region to an isochronous characteristic or a reverse dollar characteristic, and a variable displacement hydraulic driven by the engine.
• the present invention relates to a hydraulic drive device and a hydraulic drive method for a working machine including a pump.
• a variable displacement hydraulic pump driven by the engine a regulator for controlling the displacement of the hydraulic pump, and a pressure discharged from the hydraulic pump are generally used.
• a plurality of hydraulic actuators driven by oil, a pressure detector that detects the discharge pressure of the hydraulic pump and outputs a discharge pressure signal, and a discharge pressure signal output from the pressure detector is input and regulated.
• a controller for outputting a control signal for controlling the displacement of the hydraulic pump during the race.
• the engine output characteristic is such that the engine speed increases as the engine output torque (engine load) decreases in the governor region where the mechanical governor is controlled. It has droop characteristics. Such droop characteristics are caused by the inertia of the flywheel included in the mechanical governor.
• the discharge pressure of the hydraulic pump will be low during empty load operation after loading earth and sand in a bucket, and the engine load will be reduced and the engine speed will increase.
• the discharge flow rate of the hydraulic pump increases, the flow rate supplied to the hydraulic actuator increases, and the hydraulic pump discharges relatively quickly. Evening speed can be obtained. As a result, the work speed in unloading operation is increased, and work efficiency can be improved.
• the governor region has an isochronous characteristic. Or have a fuel injection control device that can be controlled to reverse dollar characteristics
• the isochronous characteristic of the engine control is independent of the lightness of the engine load, that is, the engine output torque. Regardless of the decrease, the engine speed is maintained constant in the governor region.
• the reverse droop characteristic is a characteristic in which the engine speed decreases as the engine output torque (engine load) decreases.
• Such conventional technology eliminates the influence of the inertia of a flywheel, such as a mechanical governor, and achieves low fuel consumption and low noise compared to a work machine equipped with an engine that has a mechanical two-wheel governor. it can. Disclosure of the invention
• a working machine equipped with an engine that performs isochronous control or reverse droop control has the advantage of realizing low fuel consumption and low noise, but the engine speed does not increase even when the engine is lightly loaded. Therefore, there may be a problem in work.
• the work equipment is a hydraulic excavator, and the empty load operation is performed and the engine load is light, the discharge flow rate of the hydraulic pump does not increase because the engine speed does not increase.
• the engine load may be light.
• the operating speed of the hydraulic actuator does not increase as in the case of a work machine with a mechanical two-strength engine with a governor-type engine, so the operation feeling may be uncomfortable.
• An object of the present invention is to provide at least a part of the governor region with isochronous characteristics and reverse
• a hydraulic drive system equipped with an engine having a fuel injection control device that can control any of the loop characteristics work that can increase the discharge flow rate of the hydraulic pump as the engine load becomes lighter even in the governor region
• a hydraulic drive device and a hydraulic drive method for a machine work that can increase the discharge flow rate of the hydraulic pump as the engine load becomes lighter even in the governor region.
• the present invention provides a fuel injection control device capable of controlling at least a part of a governor region to one of a isochronous characteristic, a reverse droop characteristic, and a combination of the isochronous characteristic and the reverse droop characteristic.
• a hydraulic pump for a working machine comprising: an engine having a hydraulic pump driven by the engine; and a plurality of hydraulic factories driven by hydraulic oil discharged from the hydraulic pump.
• Pump absorption torque control means for controlling the displacement of the hydraulic pump so that the displacement of the hydraulic pump does not exceed a value determined by a preset pump absorption torque curve when the discharge pressure of the pump exceeds the first predetermined pressure;
• a flow rate correction control means for controlling so that the displacement volume of the hydraulic pump in accordance with decreases from the second predetermined pressure is increased.
• the engine when the engine load during operation is heavy and the discharge pressure of the hydraulic pump is higher than the first predetermined pressure, the engine is controlled by the pump absorption torque control (pump absorption horsepower control).
• the output horsepower can be used effectively.
• the flow rate correction control means pushes the hydraulic pump in accordance with a decrease in the pump discharge pressure.
• the displacement is controlled so as to increase, so that the discharge flow rate of the hydraulic pump can be increased in the governor region even if the engine speed does not increase due to the isochronous characteristic or the reverse droop characteristic. Overnight speed can be increased.
• the present invention provides a fuel injection system in which at least a part of the governor region can be controlled to any of isochronous characteristics, reverse droop characteristics, or a combination of isochronous characteristics and reverse droop characteristics.
• An engine having a control device; a variable displacement hydraulic pump driven by the engine; and a plurality of hydraulic actuators driven by pressure oil discharged from the hydraulic pump.
• the hydraulic pump for controlling the displacement of the hydraulic pump, a pressure detector for detecting a discharge pressure of the hydraulic pump, and a pressure detector for detecting the discharge pressure of the hydraulic pump.
• a pump absorption torque control means for controlling the regulation so that the displacement of the hydraulic pump does not exceed a value determined by a preset pump absorption torque curve when the discharge pressure exceeds a first predetermined pressure; and the hydraulic pump.
• the flow rate correction control means for controlling the regulator so that the displacement of the hydraulic pump increases as the discharge pressure of the hydraulic pump decreases from the second predetermined pressure.
• the pump output torque control (pump absorption horsepower control) effectively utilizes the output horsepower of the engine and the pump discharge flow rate when the engine is lightly loaded. Increase control becomes possible, and the hydraulic actuator speed can be increased when the engine is lightly loaded.
• the second predetermined pressure is equal to the first predetermined pressure.
• the flow rate correction control means functions immediately, and the displacement of the hydraulic pump can be increased.
• control canceling means for invalidating the increase control of the displacement of the hydraulic pump by the flow rate correction control means.
• the fuel injection control device is capable of controlling at least a part of the governor region to have an isochronous characteristic
• the control release means is preferably provided with a traveling mode switch. Includes at least one of a lifting mode switch and a leveling mode switch.
• the hydraulic actuator speed is set to a constant speed regardless of the increase or decrease of the engine load. Traveling operation, lifting work, and ground preparation work can be performed.
• the flow rate correction control controls the displacement of the hydraulic pump so that the discharge flow rate of the hydraulic pump increases as the discharge pressure of the hydraulic pump decreases from the second predetermined pressure.
• the discharge flow rate of the hydraulic pump can be increased in the governor region even if the engine speed does not increase due to the isochronous characteristic or the reverse droop characteristic.
• the fuel injection control device can control at least a part of the governor region to have a reverse droop characteristic
• the flow rate correction control means First means for controlling the displacement of the hydraulic pump so that the discharge flow rate of the hydraulic pump increases as the discharge pressure of the hydraulic pump decreases from the second predetermined pressure; and (2) Select the second means for controlling the displacement of the hydraulic pump so that the discharge flow rate of the hydraulic pump is kept constant when the pressure decreases from a predetermined pressure, and select one of the first means and the second means Selection means to perform the selection.
• the discharge flow rate of the hydraulic pump is controlled to increase when the first means is selected, and the discharge flow rate of the hydraulic pump is kept constant when the second means is selected.
• the flow is controlled in accordance with the work content.
• the flow rate correction control means further includes a third means for invalidating the increase control of the displacement of the hydraulic pump, and the selection means includes: One of the first means, the second means, and the third means is selected.
• the control for increasing the displacement of the hydraulic pump is invalidated, and the flow rate can be controlled according to the work content.
• the pump absorption torque control means includes a target displacement for controlling a pump absorption torque based on a discharge pressure of the hydraulic pump and a pump absorption torque curve.
• the pump absorption torque control means and the flow rate correction control means can be computerized.
• the pump absorption torque control means limits the maximum value of the displacement of the hydraulic pump to a value not more than a value determined by the pump absorption torque curve.
• the flow rate correction control means is means for controlling so that the maximum value of the displacement of the hydraulic pump increases as the discharge pressure of the hydraulic pump decreases from a second predetermined pressure.
• pump absorption torque control pump absorption horsepower control
• pump discharge flow rate when the engine is lightly loaded. If the required flow rate in the factory is small, the displacement of the hydraulic pump is controlled accordingly to obtain a desired factory speed.
• (11) Further, in the above (1) or (2), further comprising a first calculating means for calculating a first target displacement according to a required flow rate of the plurality of hydraulic factories, wherein the pump absorption torque control The means calculates a second target displacement for pump absorption torque control from the discharge pressure of the hydraulic pump and the pump absorption torque curve, and when the discharge pressure of the hydraulic pump is equal to or lower than the first predetermined pressure.
• the corrected second target displacement becomes the target displacement for control
• the displacement of the hydraulic pump becomes the corrected second target displacement.
• pump absorption torque control pump absorption horsepower control
• the first target displacement becomes the target displacement for control, so that the displacement of the hydraulic pump is equal to the first target displacement. It is controlled according to the required flow rate based on the volume, and a desired factor overnight speed can be obtained.
• the present invention controls at least a part of the governor region to any one of the isochronous characteristic, the reverse droop characteristic, and the characteristic combining the isochronous characteristic and the reverse droop characteristic.
• a work machine comprising: an engine having a possible fuel injection control device; a variable displacement hydraulic pump driven by the engine; and a plurality of hydraulic factories driven by hydraulic oil discharged from the hydraulic pump.
• the hydraulic driving method of (1) when the discharge pressure of the hydraulic pump exceeds the first predetermined pressure, the displacement of the hydraulic pump is adjusted so that the displacement of the hydraulic pump does not exceed a value determined by a predetermined pump absorption torque curve.
• the discharge pressure of the hydraulic pump Control shall be performed so that the displacement of the hydraulic pump increases as the pressure decreases from the constant pressure.
• the discharge flow rate of the hydraulic pump can be increased in the governor region even if the engine speed does not increase due to the isochronous characteristic or the reverse droop characteristic.
• the fuel injection control device is capable of controlling at least a part of the governor region to a reverse-drip characteristic, and the discharge pressure of the hydraulic pump
• the displacement of the hydraulic pump is increased so that the discharge flow rate of the hydraulic pump increases as the discharge pressure of the hydraulic pump decreases from the second predetermined pressure.
• FIG. 1 is a diagram showing an entire system including a hydraulic circuit of a hydraulic drive device of a working machine according to a first embodiment of the present invention.
• FIG. 2 is a diagram showing an external appearance of a hydraulic shovel on which the hydraulic drive device according to the present embodiment is mounted.
• FIG. 3 is a characteristic diagram showing a relationship between a rotation speed and an output torque of an engine having an electronic governor that performs isochronous control.
• FIG. 4 is a diagram showing the details of the structure of the Reggiore.
• FIG. 5 is a diagram showing a relationship between a control current signal supplied to the electromagnetic proportional pressure reducing valve in the regulation and a tilt angle of the hydraulic pump.
• FIG. 6 is a functional block diagram showing the arithmetic functions of the work implement controller.
• FIG. 7 is a diagram showing the relationship between the pump discharge pressure used in the second target tilt angle calculation unit of the work machine controller and the second target tilt.
• FIG. 8 is a diagram illustrating a relationship between a pump discharge pressure and a pump tilt angle correction value used in the tilt angle correction value calculation unit of the work machine controller.
• FIG. 9 is a diagram illustrating a relationship between the pump discharge pressure corrected by the adding unit and the second target pump displacement.
• FIG. 1 OA is a diagram showing the relationship between the pump discharge pressure P and the pump displacement 0 according to the related art having a mechanical governor engine for controlling the governor region to a dollar-gap characteristic
• FIG. FIG. 6 is a diagram showing a relationship between a pump discharge pressure and a pump discharge flow rate according to a conventional technique.
• FIG. 11A is a diagram showing the relationship between the pump discharge pressure P and the pump displacement 0 according to the present embodiment and a conventional technology having an engine that controls the governor region to the isochronous characteristic
• FIG. It is a figure which shows the relationship between the pump discharge pressure and the pump discharge flow rate by the same prior art and this embodiment.
• FIG. 12 is a characteristic diagram showing the relationship between the rotation speed and the output torque of an engine having an electronic governor that controls the reverse droop characteristic according to the second embodiment of the present invention.
• FIG. 13 is a functional block diagram showing an arithmetic function of a work implement controller according to the second embodiment.
• FIG. 14 is a diagram illustrating the relationship between the pump discharge pressure and the pump tilt angle correction value used in the tilt angle correction value calculation unit of the work machine controller.
• FIG. 15 is a diagram illustrating a relationship between the discharge pressure signal corrected by the adding unit and the second target displacement.
• FIG. 16A is a diagram showing the relationship between the pump discharge pressure P and the pump tilt 0 according to the conventional technology having an engine that controls the governor region to have the reverse droop characteristic
• FIG. FIG. 4 is a diagram illustrating a relationship between a pump discharge pressure and a pump discharge flow rate.
• FIG. 17A is a diagram showing the relationship between the pump discharge pressure P and the pump tilt ⁇ ⁇ ⁇ according to the second embodiment
• FIG. 17B is a diagram showing the pump discharge pressure and the pump displacement according to the second embodiment.
• FIG. 4 is a diagram showing a relationship with a discharge flow rate.
• FIG. 18 is a characteristic diagram showing the relationship between the rotation speed and output torque of an engine having an electronic governor that performs control combining the isochronous characteristic and the reverse droop characteristic according to the third embodiment of the present invention. is there.
• FIG. 19 is a diagram showing the relationship between the pump discharge pressure and the pump tilt angle correction value used in the tilt angle correction value calculation unit of the work machine controller.
• FIG. 20 is a diagram illustrating a relationship between the discharge pressure signal corrected by the adding unit and the second target displacement.
• FIG. 1 is a diagram showing an entire system including a hydraulic circuit of a hydraulic drive device for a working machine according to an embodiment of the present invention.
• the hydraulic drive device is provided in a working machine, for example, a hydraulic excavator.
• a working machine for example, a hydraulic excavator.
• an engine 1 and an electronic governor 1 2 constituting a fuel injection control device of the engine 1 are provided.
• an engine controller 13 The electronic governor 12 and the engine controller 13 are capable of controlling the governor region to have an isochronous characteristic.
• the electronic governor 12 is controlled by the engine controller 13 and injects fuel into the engine 1.
• This type of fuel injection control device is known, for example, from Japanese Patent Application Laid-Open No. H10-159599.
• the hydraulic drive device includes, for example, a swash plate type variable displacement hydraulic pump 2 driven by an engine 1 and a displacement volume (swash plate) of the hydraulic pump 2. And a plurality of hydraulic actuators, such as a hydraulic cylinder 3, a hydraulic motor 4, a hydraulic cylinder 5, 6, etc., driven by hydraulic oil discharged from the hydraulic pump 2.
• the pilot pressure for switching the directional control valves 7 to 10, the main relief valve 11 and the directional control valves 7 to 10 for controlling the flow of the pressure oil supplied to these hydraulic actuators is controlled.
• a pressure detector 14 that detects the discharge pressure of the hydraulic pump 2 and outputs a discharge pressure signal P, and a tilt angle of the swash plate of the hydraulic pump 2
• the displacement angle detector 15 that detects the displacement and outputs the displacement angle signal ⁇
• the mode selection switch 17 that can output the control unlock signal F, and the operating lever device 50,.
• a signal control valve 53 that has a combination of a shuttle valve that inputs pilot pressure and selects and outputs one of the pilot pressures, and a pilot pressure signal D that is detected by detecting the pilot pressure output from the signal control valve 53
• the output pressure detector 55, the discharge pressure signal P output from the pressure detector 14 and the tilt angle signal output from the tilt angle detector 15 and the control output from the mode selection switch 17 Release signal F, Pilot output from pressure detector 5 5
• a work machine controller 18 that inputs a pressure signal D and outputs a control current signal R for controlling the displacement volume to a regulator 16.
• FIG. 2 shows an external view of a hydraulic shovel on which the hydraulic drive device according to the present embodiment is mounted.
• the hydraulic excavator has a lower traveling body 102, an upper revolving body 103, and a front work machine 104, and the upper revolving body 103 is mounted on the lower traveling body 102 so as to be pivotable,
• the front work machine 104 is attached to the front of the upper swing body 103 so as to be vertically movable.
• the upper revolving structure 103 is provided with an engine room 105 and a driver's cab 106.
• the front work machine 104 is a multi-joint structure having a boom 108, an arm 109, and a bucket 110.
• the lower traveling body 102, the upper revolving body 103, and the front work machine 104 are respectively left and right traveling motors 111 (only one is shown), rotating motors 112, and boom cylinders 111 as an actuator.
• arm cylinder 1 1 4 bucket cylinder 1 1 5
• the lower traveling body 102 travels by rotation of the left and right traveling motors 1 1
• the upper revolving body 1 0 3 is the rotating motor 1 1
• the boom 1108 of the front work machine 104 rotates vertically by the expansion and contraction of the boom cylinder 113
• the arm cylinder 109 rotates by the expansion and contraction of the arm cylinder 114.
• the bucket 110 rotates up and down and forward and backward by expansion and contraction of the bucket cylinder 115.
• the hydraulic cylinders 3, 5, and 6 are a boom cylinder 113, an arm cylinder 111, and a bucket cylinder 115, and the hydraulic motor 4 is a rotating motor—112. .
• the operation lever devices 50,... And the mode selection switch 17 are arranged in the operator cab 106, and the engine 1 and the hydraulic pump 2 are arranged in the engine room 105.
• Hydraulic equipment and electronic equipment such as the directional control valves 7 to 10, the engine controller 13, and the work equipment controller 18, are installed at appropriate places on the upper swing body 103.
• Fig. 3 shows the relationship between the rotational speed N of the engine 1 and the output torque Te by the fuel injection control device (using the electronic governor 12 and the engine controller 13) that implements isochronous control.
• the output torque characteristic of the engine 1 is divided into a characteristic of a governor region 33 (isochronous characteristic) represented by a straight line 32 and a characteristic of a full load region represented by a curve 30.
• the governor region 33 is an output region where the governor opening is 100% or less
• the full load region is an output region where the governor opening is 100%.
• the broken line 31 shows the characteristic (droop characteristic) in the governor region of the conventional mechanical governor engine for comparison. Since the two-force lug governor has a structure in which the amount of fuel injection is adjusted by the balance between the flywheel and the spring, the governor region of the mechanical governor engine is as shown by the broken line 31 1.
• the engine has a droop characteristic in which the engine speed N increases as Te decreases.
• the engine speed N is kept at the rated speed NO by the electronic governor 12 irrespective of the decrease in the engine output torque Te. It has isochronous characteristics for performing isochronous control to maintain the above. By this isochronous control, lower fuel consumption and lower noise can be realized as compared to a working machine equipped with a mechanical governor type engine.
• Fig. 4 shows the details of the regiyure overnight.
• the regulator 16 controls the tilt angle of the hydraulic pump 2 according to the control current signal R output from the work machine controller 18 so as to match the target pump tilt angle indicated by the control current signal R. It has an electromagnetic proportional pressure reducing valve 60, a servo valve 61, and a servo piston 62.
• the proportional solenoid pressure reducing valve 60 receives the control current signal R from the work implement controller 18 and receives the control current
• the control pressure is output in proportion to the signal R
• the servo valve 61 operates by the control pressure to control the position of the servo piston 62
• the servo piston 62 drives the swash plate 2a of the hydraulic pump 2. Control its tilt angle.
• the discharge pressure of the hydraulic pump 2 is guided to the input port of the servo valve 61 via the check valve 63, and is always acting on the small diameter chamber 62a of the servo piston 62 via the passage 54. .
• the discharge pressure of the pilot pump 66 is led to the input port of the electromagnetic proportional pressure reducing valve 60, and the pressure is reduced to the control pressure by operating the electromagnetic proportional pressure reducing valve 60.
• This control pressure acts on the pilot piston 61 a of the servo valve 61 through the passage 67.
• the discharge pressure of the hydraulic pump 2 is lower than the discharge pressure of the pilot pump 66, the discharge pressure of the pilot pump 66 is guided to the input port of the servo valve 61 via the check valve 69 as servo assist pressure.
• FIG. 5 shows the control current signal R given to the electromagnetic proportional pressure reducing valve 60 and the tilt angle of the swash plate 2a of the hydraulic pump 2 (hereinafter, simply referred to as the tilt angle of the hydraulic pump 2 or the pump tilt).
• the discharge pressure of the self-pump 2 also acts on the small diameter chamber 62 a of the servo piston 62 through the passage 54, but the piston 62 moves to the right in the figure due to the area difference. I do.
• the feedback lever 71 rotates counterclockwise in the figure about the pin 72 as a fulcrum. Since the end of the feedback lever 71 is connected to the sleeve 61d by the pin 73, the sleeve 61d moves leftward in the figure.
• the movement of the servo piston 62 is performed until the notch in the opening of the sleeve 61d and the spool 61b is closed, and when it is completely closed, the servo piston 61 stops.
• the tilt angle of the hydraulic pump 2 becomes the minimum position, and the discharge flow rate of the hydraulic pump 2 becomes the minimum.
• the control current signal R becomes larger than R1 and the proportional solenoid pressure reducing valve 60 operates
• the control pressure corresponding to the operation amount of the solenoid proportional pressure reducing valve 60 passes through the passage 67 and the pilot piston of the servo valve 61. Acts on 6 1a and moves the spool 6 1b rightward in the figure to a position where it balances the force of the spring 6 1c.
• the large-diameter chamber 6 2 b of the servo piston 62 is connected to the tank 75 via a passage inside the spool 61 b.
• the feedback lever 71 rotates clockwise about the pin 72, and the sleeve 61d of the servo valve 61 moves rightward in the figure.
• the movement of the servo piston 62 is performed until the notch in the opening of the sleeve 6Id and the spool 61b closes, and when it is completely closed, the servo piston 61 stops.
• the tilt angle of the hydraulic pump 2 increases, and the discharge flow rate of the hydraulic pump 2 increases.
• the increase in the discharge flow rate of the hydraulic pump 2 is proportional to the increase in the control pressure, that is, the increase in the control current signal R.
• the spool 61b of the servo valve 61 returns to the left in the figure to a position where the spool 61b balances the force of the spring 61c.
• the discharge pressure of the hydraulic pump 2 (or the discharge pressure of the pilot pump 66) passes through the sleeve 61d of the servo valve 62, the spool 61b, and acts on the large-diameter chamber 62b of the servo piston 62 to reduce the diameter.
• the servo piston 52 moves to the right in the figure due to the area difference with the chamber 62a.
• the feedback lever 71 rotates counterclockwise in the figure with the pin 72 as a fulcrum, and the sleeve 61d of the servo valve 61 moves leftward in the figure.
• the movement of the servo piston 62 is performed until the notch in the opening of the sleeve 6Id and the spool 61b is closed, and when it is completely closed, the servo piston 61 stops.
• the tilt angle of the pump 2 becomes smaller, and the discharge flow rate of the hydraulic pump 2 Decreases.
• the decrease in the discharge flow rate of the hydraulic pump 2 is proportional to the decrease in the control pressure, that is, the decrease in the control current signal R.
• FIG. 6 is a functional block diagram showing details of the mode selection switch 17 and an arithmetic function of the work implement controller 18.
• the mode selection switch 17 includes, for example, a traveling mode switch 17a, a load mode switch 17b, and a terrain mode switch 17c, and one of these switches 17a to l7c is operated by an operator. Outputs control release signal F when operated.
• the work implement controller 18 includes a first target pump tilt angle calculating section 81, a second target pump tilt angle calculating section 82, a tilt angle correction value calculating section 83, and a switching section 84. , An addition unit 85, a minimum value selection unit 86, a subtraction unit 87, and a control current calculation unit 88.
• the first target pump tilt angle calculation unit 81 receives the pilot pressure signal D from the pressure detector 55, refers to this table in a table stored in the memory, and indicates the signal D at that time. Calculate the first target displacement of the hydraulic pump 2 corresponding to the pilot pressure.
• This first target tilt is a target tilt of positive control according to the lever operation amount (required flow rate) of the operating lever device 50,... (See FIG. 1), and the pilot pressure increases in the memory table. Therefore, the relationship between the two is set so that the first target displacement also increases.
• the second target pump displacement angle calculation unit 82 receives the discharge pressure signal P of the hydraulic pump 2 from the pressure detector 14 and refers to this to a table stored in the memory.
• the second target displacement ⁇ T of the hydraulic pump 2 corresponding to the pump discharge pressure indicated by P (hereinafter, for convenience, the same sign P as the signal) is calculated.
• the second target displacement ⁇ T is a limit value for controlling the torque of the hydraulic pump 2
• the table of the memory stores the pump discharge pressure based on the pump absorption torque curve as shown in FIG.
• the relationship between P and the second target tilt (limit value) of the hydraulic pump 2 is set.
• reference numeral 20 denotes a pump absorption torque curve, which is set to match the curve 21 of the output torque Te (see FIG. 3) at a predetermined rotation speed (for example, the rated rotation speed NO) of the engine 1. .
• the pump discharge pressure P is in the range of P1 or more, the second target pump displacement changes along its pump absorption torque curve 20 and the pump discharge As the pressure P increases, the second target pump displacement ⁇ T decreases.
• the second target pump displacement ⁇ T is the first maximum displacement ⁇ maxl. If the discharge pressure P is lower than P1, the second target pump displacement ⁇ The tilt is kept at the first maximum tilt 0 maxl.
• the first maximum tilt 0 maxl is based on the design specifications of the hydraulic excavator, for example, the above-described swing motor 1 1 2, boom cylinder 1 1 3, arm cylinder 1 1 4, bucket cylinder 1 1 5 (hydraulic cylinders 3, 4, This value is determined by design specifications such as the operating speed of 6 and the hydraulic motor 4). In other words, the first maximum displacement 0 maxl is set so that the pump discharge flow rate obtained thereby gives a desired operating speed for those factories.
• P min is the minimum discharge pressure of the hydraulic pump 2
• Pmax is the maximum discharge pressure of the hydraulic pump 2.
• the maximum discharge pressure P max corresponds to the set pressure of the main relief valve 11 (see Fig. 1).
• a range 23 between the minimum discharge pressure Pmin and the pressure P1 is a region corresponding to the governor region 33 described above.
• the absorption torque of the hydraulic pump 2 is represented by the product of the discharge pressure of the hydraulic pump 2 and the displacement (tilt angle) of the hydraulic pump 2. Therefore, the second target tilt 0 T corresponding to the pump discharge pressure P is calculated from the pump absorption torque curve 20, and the tilt angle of the hydraulic pump 2 is controlled to be the second target pump tilt 0 T. This means that the hydraulic pump 2 tilts so that the product of the pump discharge pressure P and the second target pump tilt (absorbing torque of the hydraulic pump 2) is maintained at the pump absorbing torque (constant value) represented by the curve 20.
• the tilt angle correction value calculation unit 83 receives the discharge pressure signal P of the hydraulic pump 2 from the pressure detector 14 and refers to the table to a table stored in the memory. Calculates the correction value S of the second target displacement of the hydraulic pump 2 corresponding to the pump discharge pressure indicated by (hereinafter similarly denoted by the same reference symbol P as the signal).
• the correction value S is controlled by the isochronous control to increase the displacement angle of the hydraulic pump 2 as the engine load becomes lighter, even when the engine speed in the governor region 33 (FIG. 3) is constant, and the discharge flow rate is reduced. This is for correcting the tilt angle of the hydraulic pump 2 so that it increases, and the table in the memory stores the correction value when the pump discharge pressure P is equal to or higher than P1, as shown in FIG.
• S 0 and the discharge pressure P becomes smaller than P1
• the relationship between the discharge pressure P and the correction value S is set so that the correction value S increases linearly proportionally as the discharge pressure P decreases. ing.
• the switching unit 84 opens when the control release signal F is output from the mode selection switch 17 to invalidate the correction value S of the target pump displacement.
• the addition unit 85 corrects the target pump displacement calculated by the tilt angle correction value calculation unit 83 to the second target displacement of the hydraulic pump 2 calculated by the second target pump displacement angle calculation unit 82.
• the value S is added, and the corrected second target tilt is calculated.
• FIG. 9 shows the relationship between the discharge pressure P corrected by the adding unit 85 and the second target displacement ⁇ T.
• the characteristic line 19 shown in FIG. 7 is corrected as shown by the characteristic line 22, and the correction is made as the pump discharge pressure P decreases from P1 to Pmin.
• the obtained second target tilt ⁇ T linearly increases from the first maximum tilt ⁇ maxl to the second maximum tilt ⁇ ma 2 (second first maximum tilt 0 maxl + S max).
• the second maximum tilt 0 max2 is set, for example, corresponding to the structural maximum tilt of the hydraulic pump 2 (pump performance limit).
• the minimum value selector 86 is configured to calculate the first target tilt> D of the hydraulic pump 2 calculated by the first target pump tilt angle calculator 81 and the second target tilt ⁇ corrected by the adder 85.
• the smaller of T is selected and set as the target tilt Sc for controlling the hydraulic pump 2.
• the corrected second target tilt is calculated. 6 T is output as the target pump displacement 0 c for control, and the target pump displacement 0 c for control is limited to the corrected second target displacement ⁇ T or less.
• the subtraction unit 87 calculates the deviation between the control target pump displacement 0 c and the displacement angle signal 0 output from the displacement angle detector 15, and the control current calculation unit 88 performs, for example, an integral control operation.
• the control current signal R is calculated from the difference ⁇ 0 by calculation.
• the tilt angle signal 0 is controlled so as to coincide with the control target pump tilt 0c.
• the hydraulic pump 2 When the engine 1 is started, the hydraulic pump 2 is driven, and one of the operation lever devices 50,... Is operated, the hydraulic oil discharged from the hydraulic pump 2 is applied to the corresponding one of the directional control valves 7 to 10.
• the hydraulic excavator is supplied to the hydraulic cylinders 3, 5, 6, or the hydraulic motor 4 via the hydraulic excavator.
• the front work machine 104 of the hydraulic excavator shown in FIG. 2 is driven to perform excavation work of earth and sand.
• the first target displacement of the hydraulic pump 2 corresponding to the pilot pressure signal D output from the pressure detector 55 is calculated by the first target pump displacement angle calculation unit 81.
• the second target pump tilt angle calculating section 82 the second target tilt of the hydraulic pump 2 corresponding to the discharge pressure signal P of the hydraulic pump 2 output from the pressure detector 14 is calculated.
• the tilt angle correction value calculating section 83 calculates a target tilt correction value S of the hydraulic pump 2 corresponding to the discharge pressure signal P of the hydraulic pump 2 output from the pressure detector 14.
• the minimum value selection unit 86 calculates in the first target pump tilt angle calculation unit 81.
• the first target tilt of the hydraulic pump 2 is selected as the target tilt ⁇ c for control, and the subtraction unit 87 and the control current calculation unit 88 adjust the tilt angle signal 0 to the target tilt 0c.
• the control current signal R is calculated, and the control current signal R is output to the electromagnetic proportional pressure reducing valve 60 of the regulator 16.
• Is discharged in proportion to the product of The discharge flow rate is a flow rate corresponding to the lever operation amount of the operation lever device, and the discharge flow rate is supplied to a corresponding one of the hydraulic cylinders 3, 5, 6, or the hydraulic motor 4, and the actuator is operated by the operation lever. It is driven at a speed corresponding to the operation amount of the device.
• the minimum value selection unit 86 calculates the second target pump tilt angle calculation unit 82.
• the second target tilt of the hydraulic pump 2 is selected as the target tilt 0 c for control, and the control current signal R calculated from the target tilt 0 c and the tilt angle signal 0 is used as a control signal.
• Pump absorption torque control Control of the tilt angle of the hydraulic pump 2 based on the pump absorption torque curve 20 is called pump absorption torque control, and control of the discharge flow rate of the hydraulic pump 2 is called pump absorption horsepower control.
• the discharge pressure P of the hydraulic pump 2 decreases from P2.
• the tilt angle of the hydraulic pump 2 is increased by the correction value S 1 compared to the first maximum tilt 0 maxl which is the tilt angle when the discharge pressure of the hydraulic pump 2 is at P 1, Accordingly, the discharge flow rate of the hydraulic pump 2 also increases.
• the correction value S increases linearly proportionally as the discharge pressure P becomes lower than P1.
• the corrected second target displacement ⁇ T is linearly proportional to the first maximum displacement ⁇ m as the pump discharge pressure P decreases from P 1 as shown by the characteristic line 22.
• the operating speed of the hydraulic cylinders 3, 5, 6, and hydraulic motor 4 can be increased accordingly.
• the characteristic indicated by the characteristic line 22 substantially matches the dollar-pull characteristic line 31 of the mechanical governor shown in FIG.
• FIGS. 10A and 10B show the relationship between the pump discharge pressure P and the pump displacement 0 and the pump discharge pressure and the pump according to the related art having a mechanical governor type engine that controls the governor region to a dollar-gap characteristic. This shows the relationship with the discharge flow rate.
• the engine speed N increases as the pump discharge pressure P decreases from P 1, so that even if the pump displacement 0 is constant, the engine speed N With the increase, the pump discharge flow rate Q increases as shown by the broken line 26. As a result, the flow rate supplied to the hydraulic actuator is increased, and the work speed in unloading operation is increased, and work efficiency can be improved.
• FIGS. 11A and 11B show the relationship between the pump discharge pressure P and the pump tilt 0 according to this embodiment and the related art having an engine for controlling the governor region to have isochronous characteristics, and the relationship between the pump discharge pressure and the pump discharge. This shows the relationship with the flow rate.
• the engine speed N is constant at the rated speed NO irrespective of the decrease in the engine output torque Te as indicated by the straight line 32 in FIG. Therefore, Pmi equivalent to governor region 3 3 In the range 23 between n and P1, if the pump tilt 0 is constant as shown by the chain line 27, the pump discharge flow rate Q will also be as shown by the chain line 28 in FIG. It is constant.
• the pump tilt ⁇ is represented by a straight line 35 corresponding to the characteristic line 22 in FIG.
• the operation or the operation that does not require the increase control of the discharge flow rate of the hydraulic pump 2 when the engine is lightly loaded includes a traveling operation, a hanging load operation, and a leveling operation.
• the operator operates a corresponding one of the switches 17 a to 17 c of the mode selection switch 17.
• the control release signal F is output from the mode selection switch 17 to the work implement controller 18, the switching section 84 is opened, and the correction value S of the target pump displacement is invalidated.
• the control for increasing the discharge flow rate of the hydraulic pump 2 based on the correction value S of the rotation angle correction value calculation unit 83 is not performed.
• the traveling mode switch 17a of the mode selection switch 17 described above is configured to operate when a signal from the detecting means for detecting the operation of the traveling operation lever is input to the work implement controller 18. It may be. The same applies to the other mode switches 17b and 17c.
• the pump discharge flow rate Q is gradually increased as the engine load becomes lighter. be able to. That is, it is possible to increase the pump discharge flow rate substantially equal to the flow rate increase due to the droop characteristic in the mechanical governor. As a result, it is possible to increase the speed of the hydraulic actuator at a light load of the engine, and to improve the work efficiency at a light load such as unloading work.
• the operation of a working machine equipped with a mechanical governor engine Good operation feeling can be given to the operator who is used to the operation.
• the correction value S by the turning angle correction value calculation unit 83 is invalidated.
• FIGS. 12 to 17B A second embodiment of the present invention will be described with reference to FIGS. 12 to 17B.
• the present invention is applied to a hydraulic drive device including an engine having a fuel injection control device capable of controlling a governor region to a reverse droop characteristic.
• the overall configuration of the hydraulic drive device according to the present embodiment is substantially the same as that of the first embodiment shown in FIG. 1 except for the following points.
• the fuel injection control device including the electronic governor 12 and the engine controller 13 shown in FIG. 1 can control the governor region to have a reverse droop characteristic.
• the engine 1 is controlled so that the rotational speed of the engine 1 decreases as the engine output torque Te (engine load) decreases.
• FIG. 12 shows the relationship between the rotational speed N of the engine 1 controlled by the reverse droop characteristic and the output torque Te.
• the engine speed N decreases as the engine output torque Te (engine load) decreases. Due to the reverse droop characteristic, the engine speed at light load can be further reduced, and further lower fuel consumption and lower noise can be realized as compared with the dollar characteristic characteristic isochronous characteristic.
• FIG. 13 is a functional block diagram illustrating the arithmetic functions of the work implement controller 18 according to the present embodiment.
• the work implement controller 18 includes a first target pump tilt angle calculating section 81, a second target pump tilt angle calculating section 82, a first tilt angle correction value calculating section 83A, and a second Tilting angle correction value calculation section 83 B, 0 setting section 83 C, switching section 84 A, addition section 85, minimum value selection section 86, subtraction section 87, control current calculation Unit 8 has the functions of 8.
• the first and second tilt angle correction value calculators 8 3 A and 8 3 B receive the discharge pressure signal P of the hydraulic pump 2 from the pressure detector 14 and store this in the memory, respectively. Referring to the table, a correction value S for the second target tilt of the hydraulic pump 2 is calculated.
• the relationship between the discharge pressure P and the correction value Sa is set so that when the discharge pressure P becomes smaller than P1, the capture value Sa increases linearly in proportion to the discharge pressure P.
• the 0 setting unit 83C outputs 0 as the correction value S.
• the mode selection switch 17A is a dial type and has first, second and third switching positions.
• the switching unit 84A selects the correction value Sa calculated by the first tilt angle correction value calculation unit 83A as shown in the figure.
• the second target displacement 0 T of the hydraulic pump 2 calculated by the second target pump displacement angle calculator 82 is selected by the switching unit 84A. Then, the corrected second target tilt is calculated by adding the corrected value S.
• FIG. 15 shows the relationship between the pump discharge pressure P corrected by the adding unit 85 and the second target displacement 0.
• the switching unit 84A selects the correction value Sa calculated by the first tilt angle correction value calculation unit 83A
• the characteristic line 19 in the range 34 corresponding to the governor region 33 is corrected as shown by the characteristic line 40.
• the fourth maximum displacement emax4 is set according to, for example, the maximum displacement (pump performance limit) in the structure of the hydraulic pump 2.
• the switching unit 84A selects the correction value Sb calculated by the second tilt angle correction value calculation unit 83B, the characteristic line 19 in the range 34 corresponding to the governor region 33 becomes like the characteristic line 41.
• the characteristic indicated by the characteristic line 40 is apparently almost identical to the droop characteristic line 31 of the mechanical governor shown in FIG. 12, and the characteristic indicated by the characteristic line 41 is the same as the characteristic line 32 of the isochronous control shown in FIG. They almost match in appearance.
• the engine 1 is controlled to the reverse-drag characteristic, and the discharge flow rate increase control of the hydraulic pump 2 is performed by either the correction value Sa or the correction value Sb. Except for this point, it is substantially the same as the first embodiment.
• the correction value Sa calculated by the first tilt angle correction value calculation unit 83A is selected, the tilt angle of the hydraulic pump 2 is increased by the characteristic line 40 shown in FIG.
• discharge flow rate increase control is performed, the mode switch 17A is switched to the second position, and the correction value Sb calculated by the second tilt angle correction value calculator 83b is selected.
• the control for increasing the tilt angle of the hydraulic pump 2 is performed according to the characteristic line 41 shown in FIG.
• Figures 16A and 16B show the relationship between the pump discharge pressure P and the pump displacement 0 and the relationship between the pump discharge pressure and the pump discharge flow rate according to the conventional technology having an engine that controls the governor region to the reverse droop characteristic. Show.
• the calculation function of the work implement controller does not include the tilt angle correction value calculation unit 83, the switching unit 84, and the addition unit 85 shown in FIG. 6, it corresponds to the governor region 33.
• the pump displacement 0 is constant as shown by the straight line 25.
• the engine speed N decreases as the engine output torque (engine load) Te decreases, as indicated by the straight line 34 in FIG. Therefore, in the range 23 between P min and P 1, the engine speed N decreases as the pump discharge pressure P decreases from P 1, so that even if the pump displacement 0 is constant, the engine speed N Due to the decrease, the pump discharge flow rate Q decreases as shown by the broken line 44.
• the flow rate supplied to the hydraulic actuator is reduced, and the working speed in the unloading operation is lower than that in the case of the isochronous control.
• FIG. 17A and FIG. 17B show the relationship between the pump discharge pressure P and the pump tilt angle and the relationship between the pump discharge pressure and the pump discharge flow rate according to the present embodiment.
• the pump displacement 0 changes as a straight line 45 corresponding to the characteristic line 40 in FIG.
• the flow rate Q changes as shown by the straight line 46 as the pump tilt S increases. That is, even if the engine speed N decreases due to the reverse droop characteristic, the pump discharge flow rate Q increases linearly as the pump discharge pressure P decreases from P1. As a result, similarly to the prior art shown in FIGS.
• the flow rate supplied to the hydraulic actuator is increased, the working speed in the unloading operation is increased, and the working efficiency can be improved.
• the correction value Sb calculated by the second tilt angle correction value calculation unit 83B is selected and the characteristic line 19 shown in Fig. 15 is corrected to the characteristic line 41, the governor region 3 In the range 23 between Pmin and P1, which corresponds to 3, the pump displacement 0 changes as the straight line 47 corresponding to the characteristic line 41 in Fig. 15, and the pump discharge flow Q changes As S increases, it becomes as shown by the straight line 48.
• the same effects as those of the first embodiment can be obtained in the hydraulic drive device including the engine controlled to the reverse dollar characteristic.
• the mode switch 17A to the first position and selecting the correction value Sa calculated by the first tilt angle correction value calculator 83A, even in the governor region 33, As the engine load becomes lighter, the pump discharge flow rate Q can be gradually increased, and the increase in the flow rate due to the droop characteristic in the mechanical governor can be almost as large as the increase in the pump discharge flow rate.
• the mode switching switch 17A is switched to the second position, and the mode is calculated by the second tilt angle correction value calculator 83B.
• the correction value Sb the discharge flow rate of the hydraulic pump 2 becomes constant irrespective of the engine load
• the speed of the hydraulic actuator is set to the same speed regardless of the increase or decrease of the engine load, and good running operation and lifting , Leveling work can be performed.
• the hydraulic pump 2 since the hydraulic pump 2 is driven by using the engine controlled to the reverse drive characteristic, it is lighter than the first embodiment using the engine controlled to the isochronous characteristic. The engine speed at the time of load can be further reduced, and further low fuel consumption and low noise can be realized.
• the present invention is applied to the hydraulic drive device including the engine that controls the governor region with isochronous characteristics or reverse droop characteristics.
• the characteristics of the governor region are not limited thereto.
• the present invention is applied to an engine having an engine whose governor region is controlled to a combination of the isochronous characteristic and the reverse droop characteristic.
• Figure 18 shows the relationship between the engine speed N and the output torque Te controlled to a combination of isochronous characteristics and reverse droop characteristics.
• an iso-rotation speed N is maintained at a constant value of the rated speed NO regardless of a decrease in the engine output torque Te (engine load). It has a characteristic 90 that combines a chronous characteristic and a reverse droop characteristic in which the engine speed N decreases as the engine output torque Te decreases, as shown by a straight line 90 Ob.
• the engine speed is kept constant by the isochronous characteristic at the time of medium load, a certain speed of the engine is secured, noise and fuel consumption are improved, and when the engine load is lighter, the reverse Droop characteristics can further improve noise and fuel efficiency.
• FIG. 19 is a diagram showing the characteristics of the pump tilt correction value S in the tilt angle correction value calculation unit 83 (see FIG. 6) when the engine has such a characteristic 90.
• the characteristics of the pump displacement correction value S are plotted according to the characteristics of the straight lines 90a and 90b shown in Fig. 18. Line is set.
• FIG. 20 is a characteristic diagram similar to FIG. 9 in a case where the correction value S of the tilt angle correction value calculating section 83 has the characteristic shown in FIG.
• the characteristic line 19 is corrected to the characteristic of the polygonal line similar to the polygonal line of the correction value S like the characteristic line 91.
• the pump tilt in the range 23 between Pmin and P 1 corresponding to the governor region 33 is performed. 0 changes as indicated by the characteristic line 91, and accordingly, the discharge flow rate of the hydraulic pump changes as indicated by the straight line 36 in FIG. 11B, and the pump discharge flow rate increases as in the first embodiment. Control can be performed.
• the characteristic of the correction value S for increasing the pump discharge flow rate at the time of the engine light load in which the pump discharge pressure P is equal to or less than P1 substantially matches the droop characteristic in the mechanical governor.
• a pump capable of increasing the discharge flow rate of the pump is set, the present invention is not limited to the setting of such discharge flow characteristics.
• the slope of the characteristic line of the pump displacement correction value S shown in FIG. 8 may be made larger so that the pump discharge flow rate increases more than the pump discharge flow rate increases due to the droop characteristic, and vice versa. You may.
• the characteristic line of the pump displacement correction value S shown in FIG. 8 may be a broken line.
• the characteristic line of the pump displacement correction value S may be a curve instead of a straight line.
• the pump discharge pressure at which the correction value S is 0 is made equal to P1, which is the start pressure of the control based on the pump absorption torque curve 20, but may be a lower pressure.
• one characteristic corresponding to the dollar-pull characteristic is set as the characteristic of the correction value S for increasing the pump discharge flow rate at the time of light load of the engine in which the pump discharge pressure P becomes P1 or less.
• one or more other characteristics may be set so that the operator can select one of them by switching the mode selection switch.
• the mode selection switch may be a dial type that continuously changes the output so that the characteristic of the correction value S can be continuously changed.
• the electronic governor 12 is used as the electronic governor 12 in the fuel injection control device capable of controlling to the isochronous characteristic or the reverse dollar characteristic.
• the present invention is not limited to this.
• a common rail fuel injection control device or a unit fuel injector control device capable of controlling the injection amount regardless of the rotation speed may be provided.
• the tilt angle control of the hydraulic pump 2 according to the required flow rate, the absorption torque control of the hydraulic pump 2 (absorption horsepower control), the tilting of the hydraulic pump at light load, which is a feature of the present invention, are described. All the calculation of the command value of the turning angle increase control was performed by the work equipment controller 18 and the control current signal was sent to the Regulayer 16 to control the tilt angle of the hydraulic pump.
• the control of the tilt angle of the hydraulic pump 2 according to the required flow rate and the control of the absorbing torque of the hydraulic pump 2 (absorbing horsepower control) may be performed hydraulically by a regi- ration.
• the tilt angle of the hydraulic pump 2 is detected by the tilt angle detector 15 and the tilt angle is controlled by the feedback buckle so that the tilt angle matches the target tilt angle.
• the displacement angle of the hydraulic pump may be controlled in an open loop without providing the displacement angle detector 15.
• a hydraulic drive apparatus including an engine capable of controlling at least a part of a governor region to one of an isochronous characteristic, a reverse droop characteristic, and a combination of the isochronous characteristic and the reverse droop characteristic.
• a good operation feeling can be given to an operator who is accustomed to the operation of a working machine equipped with a mechanical governor type engine.
• control for selectively keeping the discharge flow rate of the oil pump constant is realized.
• the operating speed of the hydraulic actuator can be kept constant irrespective of the increase or decrease of the engine load, and the operation or operation desired by the operating can be performed well.

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Computer Hardware Design (AREA)
• Physics & Mathematics (AREA)
• Fluid Mechanics (AREA)
• Operation Control Of Excavators (AREA)
• Fluid-Pressure Circuits (AREA)
• Control Of Vehicle Engines Or Engines For Specific Uses (AREA)

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• 2002
  • 2002-06-20 JP JP2003507430A patent/JP4077789B2/ja not_active Expired - Fee Related
  • 2002-06-20 CN CNB028021258A patent/CN1300471C/zh not_active Expired - Fee Related
  • 2002-06-20 DE DE60238983T patent/DE60238983D1/de not_active Expired - Lifetime
  • 2002-06-20 EP EP02738772A patent/EP1398512B1/de not_active Expired - Lifetime
  • 2002-06-20 AU AU2002313244A patent/AU2002313244B2/en not_active Ceased
  • 2002-06-20 WO PCT/JP2002/006138 patent/WO2003001067A1/ja not_active Application Discontinuation
  • 2002-06-20 KR KR1020037002428A patent/KR100540772B1/ko not_active IP Right Cessation

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