WO2014084213A1 - Dispositif d'entraînement hydraulique d'équipement hydraulique électrique - Google Patents

Dispositif d'entraînement hydraulique d'équipement hydraulique électrique Download PDF

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Publication number
WO2014084213A1
WO2014084213A1 PCT/JP2013/081795 JP2013081795W WO2014084213A1 WO 2014084213 A1 WO2014084213 A1 WO 2014084213A1 JP 2013081795 W JP2013081795 W JP 2013081795W WO 2014084213 A1 WO2014084213 A1 WO 2014084213A1
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WIPO (PCT)
Prior art keywords
pressure
hydraulic
hydraulic pump
control
main pump
Prior art date
Application number
PCT/JP2013/081795
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English (en)
Japanese (ja)
Inventor
高橋　究
夏樹 中村
圭文 竹林
和繁 森
Original Assignee
日立建機株式会社
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Priority to JP2014550200A priority Critical patent/JP6005176B2/ja
Priority to CN201380046824.6A priority patent/CN104619996B/zh
Publication of WO2014084213A1 publication Critical patent/WO2014084213A1/fr

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    • E—FIXED CONSTRUCTIONS
    • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02F—DREDGING; SOIL-SHIFTING
    • E02F3/00—Dredgers; Soil-shifting machines
    • E02F3/04—Dredgers; Soil-shifting machines mechanically-driven
    • E02F3/28—Dredgers; Soil-shifting machines mechanically-driven with digging tools mounted on a dipper- or bucket-arm, i.e. there is either one arm or a pair of arms, e.g. dippers, buckets
    • E02F3/30—Dredgers; Soil-shifting machines mechanically-driven with digging tools mounted on a dipper- or bucket-arm, i.e. there is either one arm or a pair of arms, e.g. dippers, buckets with a dipper-arm pivoted on a cantilever beam, i.e. boom
    • E02F3/32—Dredgers; Soil-shifting machines mechanically-driven with digging tools mounted on a dipper- or bucket-arm, i.e. there is either one arm or a pair of arms, e.g. dippers, buckets with a dipper-arm pivoted on a cantilever beam, i.e. boom working downwardly and towards the machine, e.g. with backhoes
    • E02F3/325—Backhoes of the miniature type
    • E—FIXED CONSTRUCTIONS
    • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02F—DREDGING; SOIL-SHIFTING
    • E02F9/00—Component parts of dredgers or soil-shifting machines, not restricted to one of the kinds covered by groups E02F3/00 - E02F7/00
    • E02F9/20—Drives; Control devices
    • E02F9/2058—Electric or electro-mechanical or mechanical control devices of vehicle sub-units
    • E02F9/2095—Control of electric, electro-mechanical or mechanical equipment not otherwise provided for, e.g. ventilators, electro-driven fans
    • E—FIXED CONSTRUCTIONS
    • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02F—DREDGING; SOIL-SHIFTING
    • E02F9/00—Component parts of dredgers or soil-shifting machines, not restricted to one of the kinds covered by groups E02F3/00 - E02F7/00
    • E02F9/20—Drives; Control devices
    • E02F9/22—Hydraulic or pneumatic drives
    • E02F9/2221—Control of flow rate; Load sensing arrangements
    • E02F9/2225—Control of flow rate; Load sensing arrangements using pressure-compensating valves
    • E02F9/2228—Control of flow rate; Load sensing arrangements using pressure-compensating valves including an electronic controller
    • E—FIXED CONSTRUCTIONS
    • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02F—DREDGING; SOIL-SHIFTING
    • E02F9/00—Component parts of dredgers or soil-shifting machines, not restricted to one of the kinds covered by groups E02F3/00 - E02F7/00
    • E02F9/20—Drives; Control devices
    • E02F9/22—Hydraulic or pneumatic drives
    • E02F9/2278—Hydraulic circuits
    • E02F9/2285—Pilot-operated systems
    • E—FIXED CONSTRUCTIONS
    • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02F—DREDGING; SOIL-SHIFTING
    • E02F9/00—Component parts of dredgers or soil-shifting machines, not restricted to one of the kinds covered by groups E02F3/00 - E02F7/00
    • E02F9/20—Drives; Control devices
    • E02F9/22—Hydraulic or pneumatic drives
    • E02F9/2278—Hydraulic circuits
    • E02F9/2296—Systems with a variable displacement 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
    • 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
    • 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
    • F15B2211/20515—Electric motor
    • 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
    • F15B2211/25—Pressure control functions
    • F15B2211/251—High pressure control
    • 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
    • F15B2211/6313—Electronic controllers using input signals representing a pressure the pressure being a load 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
    • F15B2211/665—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
    • F15B2211/6653—Pressure control

Definitions

  • the present invention relates to a hydraulic drive device of an electric hydraulic work machine such as a hydraulic excavator that drives a hydraulic pump by an electric motor to drive an actuator, and in particular, a discharge pressure of the hydraulic pump is more constant than a maximum load pressure.
  • the present invention relates to a so-called load-sensing hydraulic drive device that controls the discharge flow rate of a hydraulic pump so as to increase only the pressure.
  • Patent Documents 1 and 2 describe an electric hydraulic working machine such as a hydraulic excavator that performs various operations by driving a hydraulic pump by an electric motor to drive an actuator.
  • the electric hydraulic work machine of Patent Document 1 includes a fixed displacement hydraulic pump driven by an electric motor, and the electric motor is configured so that the differential pressure between the discharge pressure of the hydraulic pump and the maximum load pressure of a plurality of hydraulic actuators is constant.
  • the load sensing control is performed by controlling the number of rotations.
  • the electric hydraulic working machine described in Patent Document 2 includes a variable displacement hydraulic pump driven by an electric motor (variable speed motor), and controls the rotational speed of the electric motor and the cutoff control of the regulator of the hydraulic pump (hydraulic pump).
  • variable speed motor variable speed motor
  • cutoff control of the regulator of the hydraulic pump hydroaulic pump
  • JP 2008-256037 A Japanese Patent Laid-Open No. 2003-172302
  • load sensing control can be performed by controlling the number of revolutions of the motor without using a variable displacement pump that performs complicated flow rate control.
  • Load sensing system can be installed.
  • a relief valve connected to the pressure oil supply oil path from the hydraulic pump functions to cause the pressure oil supply oil path to Pressure oil is discharged into the tank, and the discharge pressure of the hydraulic pump is maintained at the set pressure (relief pressure) of the relief valve.
  • the hydraulic drive device of Patent Document 1 is configured to perform only load sensing control by controlling the rotational speed of the electric motor, for example, when an actuator such as a boom cylinder reaches the stroke end as described above, the hydraulic pump The pressure difference between the discharge pressure and the maximum load pressure becomes almost zero, and the rotational speed of the motor is controlled so that the differential pressure becomes equal to the target differential pressure.
  • the discharge flow rate of the hydraulic pump increases to the maximum, and the flow rate that flows out from the relief valve to the tank also increases to the maximum. Therefore, the above-mentioned problem (operation of the work machine due to an increase in the battery discharge amount due to the occurrence of unnecessary power consumption)
  • the reduction in time and the increase in hydraulic oil cooling system capacity are particularly significant.
  • An object of the present invention is to reduce wasteful power consumption due to relief valve operation in an electric hydraulic working machine that drives a hydraulic pump by an electric motor to drive an actuator and performs load sensing control by controlling the rotational speed of the electric motor, and
  • An object of the present invention is to provide a hydraulic drive device for an electric hydraulic working machine that can suppress a sudden increase in the number of revolutions of the electric motor and can ensure comfort with higher efficiency.
  • the present invention includes an electric motor, a hydraulic pump driven by the electric motor, a plurality of actuators driven by pressure oil discharged from the hydraulic pump, and the hydraulic pump.
  • a plurality of flow rate control valves for controlling the flow rate of pressure oil supplied to the plurality of actuators, and a pressure oil supply oil passage for supplying discharge oil of the hydraulic pump to the plurality of flow rate control valves;
  • Hydraulic drive of an electric hydraulic work machine having a relief valve that opens when the discharge pressure exceeds a set pressure and returns the pressure oil in the pressure oil supply oil passage to the tank, and a power storage device that supplies electric power to the electric motor
  • Load sensing control for controlling the rotational speed of the hydraulic pump so that a discharge pressure of the hydraulic pump is higher than a maximum load pressure of the plurality of actuators by a target differential pressure in the apparatus Cut-off control for controlling the number of revolutions of the hydraulic pump so as to reduce the discharge flow rate of the hydraulic pump when the discharge pressure of the hydraulic pump rises to a first predetermined pressure
  • the hydraulic speed control device is configured to reduce the hydraulic pump discharge flow rate when the discharge pressure of the hydraulic pump rises above the first predetermined pressure near the set pressure of the relief valve.
  • a plurality of actuators include a hydraulic cylinder, and when this hydraulic cylinder reaches the stroke end, the flow rate discharged from the hydraulic pump can be suppressed. Therefore, it is possible to suppress the power that is wasted from the relief valve.
  • the power consumption of the electric motor is reduced, the power storage device that is the electric power source of the electric motor can be prolonged, and the operating time of the electric hydraulic working machine can be extended. Furthermore, since the heat generation during the operation of the relief valve is reduced, the hydraulic oil cooling system can be downsized.
  • the motor rotation speed control device includes a first pressure sensor that detects a discharge pressure of the hydraulic pump, a second pressure sensor that detects the maximum load pressure, and the electric motor.
  • a load sensing control calculation unit that calculates a virtual capacity of the hydraulic pump that increases or decreases according to the positive or negative of the differential pressure difference between the pressure difference between the discharge pressure of the hydraulic pump and the maximum load pressure and the target LS differential pressure; Based on the discharge pressure of the hydraulic pump detected by the first pressure sensor, when the discharge pressure of the hydraulic pump rises above the first predetermined pressure, the virtual capacity of the cut-off control suddenly decreases.
  • a capacity limit control calculation unit that calculates a limit value, and selects a virtual capacity calculated by the load sensing control calculation unit and a smaller limit value of the virtual capacity to obtain a new virtual capacity, and the controller Calculates a target flow rate of the hydraulic pump by multiplying the new virtual capacity by the reference rotational speed, and a control command for controlling the rotational speed of the electric motor so that the discharge flow rate of the hydraulic pump becomes the target flow rate Is output to the inverter.
  • the concept of the virtual capacity of the hydraulic pump is introduced into the load sensing control calculation unit, the target flow rate of the load sensing control is obtained, and the rotation speed of the motor is controlled to perform load sensing control by controlling the rotation speed of the motor. be able to.
  • the virtual capacity limit value of the cutoff control is calculated in the capacity limit control calculation unit, and the virtual capacity calculated in the load sensing control calculation unit and the smaller one of the virtual capacity limit values are selected to obtain a new virtual capacity. In other words, by controlling the rotation speed of the electric motor, it is possible to easily realize cut-off control by controlling the rotation speed of the electric motor.
  • the discharge pressure of the hydraulic pump when the discharge pressure of the hydraulic pump is in a pressure range not less than a second predetermined pressure and not more than the first predetermined pressure, the discharge pressure of the hydraulic pump increases as the discharge pressure increases.
  • a torque control device is further provided for controlling the absorption torque of the hydraulic pump so as not to exceed a preset maximum torque by reducing the discharge flow rate of the hydraulic pump.
  • a torque control device is provided, and the discharge pressure of the hydraulic pump is in the pressure range from the second predetermined pressure to the first predetermined pressure.
  • the hydraulic pump is a variable displacement hydraulic pump, and is provided in the hydraulic pump.
  • the discharge pressure of the hydraulic pump rises, the discharge flow rate of the hydraulic pump is increased.
  • a torque control device is further provided for controlling the absorption torque of the hydraulic pump so that the absorption torque does not exceed a preset maximum torque.
  • the hydraulic pump is a fixed displacement hydraulic pump, and is incorporated as a function of the controller, and when the discharge pressure of the hydraulic pump rises, the discharge of the hydraulic pump
  • a torque control device is further provided for controlling the absorption torque of the hydraulic pump so as not to exceed a preset maximum torque by reducing the flow rate.
  • the hydraulic pump is a fixed displacement hydraulic pump
  • the capacity restriction control calculation unit is based on a discharge pressure of the hydraulic pump detected by the first pressure sensor.
  • the discharge pressure of the hydraulic pump is in a pressure range that is greater than or equal to a second predetermined pressure and less than or equal to the first predetermined pressure
  • the limit value of the virtual capacity of torque limit control that decreases as the discharge pressure of the hydraulic pump increases
  • the virtual capacity limit value of the cutoff control that suddenly decreases from the virtual capacity limit value of the torque limit control is calculated, and the load sensing control
  • the virtual capacity calculated by the calculation unit and the smaller one of the limit values of the virtual capacity are selected to obtain a new virtual capacity.
  • an operation device for instructing the reference rotation speed is further provided, and the controller sets the reference rotation speed based on an instruction signal of the operation device, and the reference rotation Based on the number, the target LS differential pressure and the target flow rate corresponding to the magnitude of the reference rotational speed are calculated.
  • an electric hydraulic work machine that drives a hydraulic pump by an electric motor to drive an actuator and performs load sensing control by controlling the rotational speed of the electric motor
  • wasteful power consumption due to the relief valve operation is suppressed, and the electric motor rotational speed is rapidly increased.
  • the rise can be suppressed, and comfort can be ensured with higher efficiency.
  • the electric power consumption of the electric motor is reduced, the power storage device that is the electric power source of the electric motor can be prolonged, and the operating time of the electric hydraulic working machine can be extended.
  • the hydraulic oil cooling system can be downsized.
  • Pq characteristic pump discharge pressure-pump capacity characteristic
  • FIG. 1 is a diagram showing a configuration of a hydraulic drive device for an electric hydraulic work machine according to a first embodiment of the present invention.
  • the present invention is applied to a hydraulic drive device of a front swing type hydraulic excavator.
  • a hydraulic drive apparatus includes an electric motor 1, a variable displacement hydraulic pump (hereinafter referred to as a main pump) 2 as a main pump driven by the electric motor 1, and a fixed displacement pilot pump. 30, a plurality of actuators 3 a, 3 b, 3 c... Driven by pressure oil discharged from the main pump 2, and a control valve 4 positioned between the main pump 2 and the plurality of actuators 3 a, 3 b, 3 c.
  • a main pump variable displacement hydraulic pump
  • a pilot hydraulic power source 38 that is connected to the pilot pump 30 via a pilot oil passage 31 and generates a pilot primary pressure based on the oil discharged from the pilot pump 30; and a downstream side of the pilot hydraulic power source 38, and a gate lock lever And a gate lock valve 100 as a safety valve operated by the control unit 24.
  • the control valve 4 includes a second pressure oil supply oil passage 4a (internal passage) connected to a first pressure oil supply oil passage 2a (piping) to which discharge oil of the main pump 2 is supplied, and a second pressure oil supply oil.
  • a plurality of closed center type flow rate controls connected to the oil passages 8a, 8b, 8c... Branching from the passage 4a and controlling the flow rate and direction of the pressure oil supplied from the main pump 2 to the actuators 3a, 3b, 3c.
  • the flow control valves 6a, 6b, 6c... Have load ports 26a, 26b, 26c..., Respectively, and these load ports 26a, 26b, 26c... Are when the flow control valves 6a, 6b, 6c. Communicates with the tank T and outputs a tank pressure as a load pressure.
  • the respective actuators 3a, 3b, 3c are switched from the neutral position to the left and right operation positions in the figure, the respective actuators 3a, 3b, 3c. To output the load pressure of the actuators 3a, 3b, 3c.
  • the shuttle valves 9a, 9b, 9c... are connected in a tournament form, and constitute the maximum load pressure detection circuit together with the load ports 26a, 26b, 26c. That is, the shuttle valve 9a selects and outputs the high pressure side of the pressure of the load port 26a of the flow control valve 6a and the pressure of the load port 26b of the flow control valve 6b, and the shuttle valve 9b outputs the output pressure of the shuttle valve 9b. And the pressure of the load port 26c of the flow control valve 6c are selected and output, and the shuttle valve 9c outputs the high pressure side of the output pressure of the shuttle valve 9b and the output pressure of another similar shuttle valve (not shown). Select and output.
  • the shuttle valve 9c is the last stage shuttle valve, and its output pressure is output to the signal oil passage 27 as the maximum load pressure, and the maximum load pressure output to the signal oil passage 27 passes through the signal oil passages 27a, 27b, 27c. Through the pressure compensation valves 7a, 7b, 7c... And the unload valve 15.
  • the pressure compensating valves 7a, 7b, 7c,... Are pressure-receiving portions 21a, 21b, 21c, etc., which are operated in the closing direction, in which the highest load pressure is guided from the shuttle valve 9c via the signal oil passages 27, 27a, 27b, 27c,. It has pressure-receiving parts 22a, 22b, 22c ... of the opening direction operation to which the downstream pressure of the meter-in throttle part of the control valves 6a, 6b, 6c ... is guided, and the downstream pressure of the meter-in throttle part of the flow control valves 6a, 6b, 6c ... Is controlled to be equal to the maximum load pressure.
  • the differential pressure across the meter-in throttle portion of the flow control valves 6a, 6b, 6c... Is controlled to be equal to the differential pressure between the discharge pressure of the main pump 2 and the maximum load pressure.
  • the unload valve 15 is operated in the open direction in which the closing direction spring 15a that sets the cracking pressure Pun0 of the unload valve 15 and the pressure in the second pressure oil supply oil passage 4a (the discharge pressure of the main pump 2) is guided.
  • the pressure of the pressure oil supply oil passage 4a is set to the maximum load pressure and the set pressure Pun0 ( When the pressure becomes higher than the cracking pressure, the pressure oil in the pressure oil supply oil passage 4a is returned to the tank T and the pressure in the pressure oil supply oil passage 4a (the discharge pressure of the main pump 2) is set to the maximum load pressure.
  • the pressure is controlled by adding the set pressure of the spring 15a and the pressure generated by the override characteristic of the unload valve 15.
  • the override characteristic of the unload valve is a characteristic in which the inlet pressure of the unload valve, that is, the pressure of the pressure oil supply oil passage 4a increases as the flow rate of the pressure oil that returns to the tank via the unload valve increases.
  • a pressure obtained by adding the set pressure of the spring 15a and the pressure generated by the override characteristic of the unload valve 15 to the maximum load pressure is referred to as an unload pressure.
  • Actuators 3a, 3b, and 3c are, for example, boom cylinders, arm cylinders, and swing motors of hydraulic excavators, and flow control valves 6a, 6b, and 6c are, for example, flow control valves for booms, arms, and swings.
  • flow control valves 6a, 6b, and 6c are, for example, flow control valves for booms, arms, and swings.
  • illustration of other actuators such as bucket cylinders, swing cylinders, travel motors, and flow control valves related to these actuators is omitted.
  • the pilot hydraulic power source 38 is connected to the pilot oil passage 31 and has a pilot relief valve 32 that keeps the pressure of the pilot oil passage 31 constant.
  • the gate lock valve 100 can be switched between a position where the pilot oil passage 31 a is connected to the pilot oil passage 31 and a position where the pilot oil passage 31 a is connected to the tank T by operating the gate lock lever 24.
  • the hydraulic drive device includes a battery 70 (power storage device) serving as a power source for the electric motor 1, a chopper 61 that boosts DC power of the battery 70, and DC power boosted by the chopper 61.
  • An inverter 60 that converts AC power and supplies it to the electric motor 1, a reference rotational speed instruction dial 51 (operating device) that is operated by an operator and indicates the reference rotational speed of the electric motor 1, and a pressure oil supply oil passage 4 a of the control valve 4.
  • a pressure sensor 40 that detects the discharge pressure of the main pump 2
  • a pressure sensor 41 that is connected to the signal oil passage 27 and detects the maximum load pressure
  • an indication signal of the reference rotation speed indication dial 51 and the pressure sensor 40.
  • 41, and a controller 50 for controlling the inverter 60
  • FIG. 2 is a functional block diagram showing the processing contents of the controller 50.
  • the controller 50 has the functions of the calculation units 50a to 50m.
  • the calculation units 50a and 50b receive the detection signals V PS and V PLmax of the pressure sensors 40 and 41, respectively, and convert these values into the discharge pressure P PS and the maximum load pressure P PLmax of the main pump 2, respectively.
  • the calculation unit 50d has an instruction signal V EC reference rotation speed instruction dial 51 is converted to the reference rotation speed N 0, the arithmetic unit 50e converts the reference rotational speed N 0 in the target LS differential pressure P GR.
  • Calculation unit 50f calculates the difference pressure deviation ⁇ P of the target LS differential pressure P GR and the actual load sensing differential pressure P LS.
  • the calculation unit 50g calculates an increase / decrease value ⁇ q of the virtual capacity q * of the main pump 2 from the differential pressure deviation ⁇ P.
  • the calculation unit 50g is configured such that the virtual capacity change amount ⁇ q increases as ⁇ P increases.
  • the increase / decrease value ⁇ q is calculated so as to be a positive value when ⁇ P is positive and to be a negative value when ⁇ P is negative.
  • the calculation unit 50h calculates the current virtual capacity q * by adding the increase / decrease value ⁇ q to the virtual capacity q * one calculation cycle before.
  • the virtual capacity q * of the main pump 2 is the capacity of the main pump 2 for controlling the actual load sensing differential pressure P LS to match the target LS differential pressure P GR by controlling the rotational speed of the electric motor 1. Calculated value.
  • the calculation unit 50r has a table in which characteristics (hereinafter simply referred to as cut-off control characteristics) for simulating cut-off control of the discharge pressure of the main pump 2 are set, and the main pump 2 converted by the calculation unit 50a is included in the calculation unit 50r.
  • the discharge pressure P PS is input, and the calculation unit 50r calculates the limit value (maximum virtual capacity) q * limit of the virtual capacity q * of the cutoff control with reference to the discharge pressure P PS of the main pump 2 in the table. .
  • FIG. 3 is a diagram illustrating characteristics (cut-off control characteristics) simulating cut-off control set in the calculation unit 50r.
  • the cut-off control characteristic set in the calculation unit 50r is a characteristic corresponding to the maximum capacity characteristic line TP0 (see FIG. 4) of the main pump 2 when the discharge pressure of the main pump 2 is lower than the preset set value P pso . It consists of TP0r1 and a cutoff control characteristic TP3 when the discharge pressure of the main pump 2 exceeds the set value P pso .
  • the limit value q * limit in the characteristic TP0r1 is constant at the maximum capacity q max of the main pump 2.
  • the cut-off control characteristic TP3 is set so that the limit value q * limit is steeply and linearly reduced from q max to the minimum value q * limit 0 from the set value P pso to the maximum discharge pressure P max .
  • the maximum discharge pressure P max of the main pump 2 is a set pressure (relief pressure) of the main relief valve 14.
  • the set value P pso is higher than the start pressure P 0 (described later) of the constant absorption torque control and is a pressure close to the maximum discharge pressure P max .
  • the minimum value q * limit0 is a small volume close to the minimum capacity q min of the main pump 2.
  • the minimum value q * limit0 may be the same as the minimum capacity q min of the main pump 2.
  • the calculation unit 50s selects a smaller one of the load sensing control virtual capacity q * calculated by the calculation unit 50h and the limit value q * limit of the virtual capacity q * obtained by the calculation unit 50r, and creates a new virtual capacity q *. Output as *.
  • the virtual capacity q * of the load sensing control and the limit value q * limit of the virtual capacity are the same value, one of them, for example, the virtual capacity q * of the load sensing control is selected in advance as a rule. Is established.
  • the calculation unit 50i allows the obtained new virtual capacity q ** to fall within the range of the minimum capacity q min and the maximum capacity q max of the main pump 2 (not less than the minimum capacity q min and more than the maximum capacity q max Process to limit so that it does not become.
  • Calculation unit 50j multiplies the reference rotational speed N 0 in the virtual capacity q ** obtained, to calculate a target flow rate Q d of the main pump 2.
  • Calculating unit 50k is divided by the target flow rate Q d at maximum capacity q max of the main pump 2, to calculate a target rotational speed N d of the main pump 2.
  • the calculation unit 50m converts the target rotational speed Nd into a command signal (voltage command) V INV that is a control command for the inverter 60, and outputs the command signal V INV to the inverter 60.
  • the above-described function of the controller 50, the inverter 60, and the pressure sensors 40 and 41 rotate the main pump 2 so that the discharge pressure of the main pump 2 is higher by the target differential pressure than the maximum load pressure of the plurality of actuators 3a, 3b, 3c.
  • the discharge pressure of the main pump 2 and the discharge pressure of the main pump 2 rise above the first predetermined pressure P pso near the set pressure P max of the main relief valve 14, the discharge flow rate of the main pump 2 is decreased.
  • An electric motor rotation speed control device 200 that performs cut-off control for controlling the rotation speed of the main pump 2 is configured.
  • the calculation units 50a to 50c and 50f to 50h of the controller 50 are based on the discharge pressure P PS and the maximum load pressure P PLmax of the main pump 2 and the target LS differential pressure P GR detected by the pressure sensors 40 and 41, respectively.
  • the calculation unit 201 is configured.
  • the calculation units 50r and 50s of the controller 50 Based on the discharge pressure of the main pump 2 detected by the pressure sensor 40, the calculation units 50r and 50s of the controller 50 have a first predetermined pressure P pso that the discharge pressure of the main pump 2 is close to the set pressure P max of the main relief valve 14. Calculate the virtual capacity limit value q * limit of the cutoff control that suddenly decreases when it rises above, and select the smaller one of the virtual capacity q * and virtual capacity limit value q * limit calculated by the load sensing control calculation unit A capacity limit control calculation unit 202 for obtaining the virtual capacity q ** is configured.
  • the hydraulic drive device of the present embodiment is provided in the main pump 2, and the capacity of the main pump 2 is reduced as the discharge pressure of the main pump 2 increases, and the absorption torque of the main pump 2 is set in advance.
  • the torque control device 17 for controlling the maximum torque so as not to exceed the maximum torque is provided.
  • the torque control device 17 is a regulator provided in the main pump 2, and has a torque control tilt piston 17a and springs 17b1 and 17b2 to which the discharge pressure of the main pump 2 is guided through an oil passage 17c.
  • FIG. 4 shows pump torque characteristics (Pq characteristics: pump discharge pressure-pump capacity characteristics) of the torque control device 17).
  • the horizontal axis indicates the discharge pressure of the main pump 2, and the vertical axis indicates the capacity of the main pump 2.
  • TP0 the maximum capacity characteristic line of the main pump 2
  • TP1 and TP2 are characteristic of the torque control that is set by the spring 17b1,17b2
  • P 0 is the second predetermined pressure (absorption torque determined by the spring 17B1,17b2 Constant control starting pressure).
  • Torque control tilting piston 17a of the torque control device 17 is not operated when the discharge pressure of the main pump 2 is below a second predetermined pressure P 0, the maximum capacity q max on the capacity of the main pump 2 is characteristic lines TP0 It is in.
  • the torque control tilt piston 17a of the torque control device 17 operates, and the discharge pressure of the main pump 2 changes from the second predetermined pressure P 0 to the main pressure.
  • the pump 2 reaches the maximum discharge pressure P max (set pressure of the main relief valve 14), the capacity of the main pump 2 decreases from q max to qlimit-min along the characteristic lines TP1 and TP2.
  • the absorption torque (product of pump discharge pressure and capacity) of the main pump 2 is controlled to a substantially constant value so as not to exceed the maximum torque (limit torque) TM in contact with the characteristic lines TP1 and TP2.
  • This control is referred to as torque limit control in this specification, and control in terms of characteristics in which the displacement of the hydraulic pump is replaced with discharge flow rate is referred to as horsepower control.
  • the magnitude of the maximum torque TM can be freely set in advance by selecting the strength of the springs 17b1 and 17b2.
  • the main pump 2 is controlled so that the absorption torque of the main pump 2 does not exceed a preset maximum torque by decreasing the discharge flow rate of the main pump 2 as the discharge pressure of the main pump 2 increases.
  • FIG. 5 is a diagram showing an external appearance of a hydraulic excavator on which the hydraulic drive device according to the present embodiment is mounted.
  • a hydraulic excavator well known as a work machine includes an upper swing body 300, a lower traveling body 301, and a swing-type front work machine 302.
  • the front work machine 302 includes a boom 306, an arm 307, The bucket 308 is configured.
  • the upper turning body 300 can turn the lower traveling body 301 by the rotation of the turning motor 3c shown in FIG.
  • a swing post 303 is attached to the front portion of the upper swing body 300, and a front work machine 302 is attached to the swing post 303 so as to move up and down.
  • the swing post 303 can be rotated in the horizontal direction with respect to the upper swing body 300 by expansion and contraction of a swing cylinder (not shown).
  • the boom 306, the arm 307, and the bucket 308 of the front work machine 302 are the boom cylinder 3a, the arm cylinder 3b, and the bucket.
  • the cylinder 12 can be turned up and down by expansion and contraction.
  • a blade 305 that moves up and down by the expansion and contraction of a blade cylinder 304 is attached to the lower frame 301 in the center frame.
  • the lower traveling body 301 travels by driving the left and right crawler belts 310 and 311 by the rotation of the traveling motors 6 and 8.
  • FIG. 1 only the boom cylinder 3a, the arm cylinder 3b, and the turning motor 3c are shown, and the bucket cylinder 3d, the left and right traveling motors 3f and 3g, the blade cylinder 3h, and their circuit elements are omitted.
  • a cabin (driver's cab) 313 is installed in the upper swing body 300, and in the cabin 313, there is a driver seat 121, front / turning operation lever devices 122 and 123 (only the right side is shown in FIG. 5), and driving operation.
  • a lever device 124 and a gate lock lever 24 are provided.
  • the main pump 2 is driven by the electric motor 1, and the pressure oil is supplied to the pressure oil supply oil passages 2a and 4a.
  • the flow rate control valves 6a, 6b, 6c,..., The main relief valve 14, and the unload valve 15 are connected to the pressure oil supply oil passage 4a.
  • the flow rate control valves 6a, 6b, 6c,... are closed, so that the discharge pressure of the main pump 2 is a pressure obtained by adding the override characteristic pressure to the set pressure of the spring 15a of the unload valve 15. To rise.
  • the set pressure of the unload valve 15 is set to be constant by the spring 15a, and the set pressure is the target LS differential pressure P GR calculated by the calculation unit 50e when the reference rotational speed N 0 is maximum. It is set higher than.
  • the target LS differential pressure PGR is 2 MPa
  • the set pressure of the spring 15a is about 2.5 MPa
  • the discharge pressure (unload pressure) of the main pump 2 is also approximately 2.5 MPa.
  • the pressure sensor 40 connected to the pressure oil supply oil passage 4a detects the discharge pressure of the main pump 2.
  • the discharge pressure of the main pump 2 at this time is represented by Pmin .
  • the detection signal of the pressure sensor 40 is V PS and the detection signal of the pressure sensor 41 is V PLmax .
  • the controller 50 calculates the virtual capacity q * of the main pump 2 based on the detection signals V PS and V PLmax of the pressure sensors 40 and 41 and the instruction signal V EC of the reference rotation speed instruction dial 51 in the arithmetic units 50a to 50h. .
  • the discharge pressure P PS of the main pump 2 at this time is P min as described above, and in the calculation unit 50r, P PS ⁇ P pso , the virtual capacity of the cutoff control characteristic shown in FIG. Q max is calculated as the limit value q * limit.
  • the calculation point at this time is indicated by point A.
  • the calculation unit 50s selects the virtual capacity q * of the load sensing control calculated by the calculation unit 50h, and outputs this as a new virtual capacity q **.
  • the calculating unit 50j, and calculates a target flow rate Q d is multiplied by the reference rotational speed N 0 in the virtual capacity q **.
  • the calculating unit 50k by dividing the target flow rate Q d at maximum capacity q max of the main pump 2, and calculates the target rotational speed N d of the main pump 2, the calculating unit 50m, an inverter 60 the target speed N d
  • the command signal V INV is converted to the command signal V INV and the command signal V INV is output to the inverter 60.
  • the target flow rate Q d is decreased to a minimum value, and the target rotation speed N d of the main pump 2 and the command signal V INV of the inverter 60 are respectively decreased to a minimum value.
  • the rotation speed of the electric motor 1 is held at the minimum value.
  • the discharge pressure of the main pump 2 at this time is P min as described above, and since P min ⁇ P 0 , the torque control tilt piston 17a of the torque control device 17 does not operate, and the capacity of the main pump 2 is It is at the maximum q max .
  • the operating point at this time is indicated by point A.
  • the capacity of the main pump 2 is maintained at the maximum capacity q max , but the virtual capacity q ** is reduced to the minimum capacity q min by the limiting process of the arithmetic unit 50i by the load sensing control by the rotation speed control of the electric motor 1.
  • the rotation speed of the electric motor 1 is held at the minimum value, the flow rate discharged by the main pump 2 is also held at the minimum value.
  • the load pressure of the boom cylinder 3a is guided from the signal oil passage 27 to the pressure receiving portion 15c of the unload valve 15 via the load port 26a of the flow control valve 6a and the shuttle valves 9a, 9b, 9c.
  • the cracking pressure of the unload valve 15 is set to the load pressure + the set pressure of the spring 15a
  • the discharge pressure of the main pump 2 is the load pressure.
  • the pressure rises to the pressure + the set pressure of the spring 15a + the pressure of the override characteristic.
  • the pressure sensors 40 and 41 detect the discharge pressure and the maximum load pressure of the main pump 2 at this time.
  • the controller 50 calculates the virtual capacity q * of the main pump 2 based on the detection signals V PS and V PLmax of the pressure sensors 40 and 41 and the instruction signal V EC of the reference rotation speed instruction dial 51 in the arithmetic units 50a to 50h. .
  • the boom-up when starting, the discharge pressure of the main pump 2, by the action of the unloading valve 15 described above, is set slightly higher than the target LS differential pressure P GR.
  • the calculation unit 50g is configured such that the virtual capacity change amount ⁇ q increases as ⁇ P increases.
  • ⁇ q is also> 0.
  • the computing unit 50h calculates the load sensing control virtual capacity q * by adding ⁇ q to the virtual capacity q * one cycle before. Since ⁇ q> 0, the virtual capacity q * increases.
  • the discharge pressure P PS of the main pump 2 is also led to the calculation unit 50r.
  • the calculation unit 50r holds the virtual capacity limit value q * limit for cut-off control at qmax.
  • B point an example of the calculation point at this time is indicated by B point.
  • Discharge pressure of the main pump 2 is P b.
  • the arithmetic unit 50 s, and outputs a smaller virtual volume q * and q max as a new virtual volume q **.
  • Virtual capacity q * is smaller than q max outputs the virtual capacity q * as it is, the virtual capacity q * is greater than q max, and outputs the q max.
  • the new virtual capacity q ** is restricted so as not to be less than the minimum capacity q min and not more than the maximum capacity qmax.
  • the virtual capacity q ** increases from the minimum capacity q min when the control lever is neutral to the maximum capacity q max .
  • Controller 50 the virtual capacity q ** obtained in this manner, to calculate a target flow rate Q d is multiplied by the reference rotational speed N 0 in the calculating unit 50j. Further, the calculating unit 50k, by dividing the target flow rate Q d at maximum capacity q max of the main pump 2, and calculates the target rotational speed N d of the main pump 2, the calculating unit 50m, an inverter 60 the target speed N d The command signal V INV is converted to the command signal V INV and the command signal V INV is output to the inverter 60.
  • the motor 1 is controlled so as to perform load sensing control using the electric motor 1.
  • the maximum rotation speed of the electric motor 1 is the rotation speed when the virtual capacity q ** is at q max , and the maximum rotation speed is N max .
  • C point an example of the calculation point at this time is indicated by C point.
  • the discharge pressure of the main pump 2 is Pc .
  • the calculation units 50s and 50i perform the same processing as in the case of the “boom raising single operation (light load)”, and in the calculation units 50j to 50m, the command signal V INV of the inverter 60 is obtained from the virtual capacity q **. Calculated and output to the inverter 60. Therefore, the virtual capacity q * of load sensing control increases or decreases according to the operation amount (required flow rate) of the operation lever and changes from the minimum to the maximum, as in the case of “Boom raising single operation (light load)”. Similarly, the rotational speed of the electric motor 1 (the rotational speed of the main pump 2) also changes from the minimum to the maximum according to the operation amount (required flow rate) of the operation lever.
  • the characteristic lines of TP1 and TP2 in FIG. 4 are set by the springs 17b1 and 17b2, and the absorption torque of the main pump 2 (product of pump discharge pressure and capacity) —therefore, the drive torque of the electric motor 1 -Is controlled so as not to exceed the maximum torque (limit torque) TM in contact with the characteristic lines TP1 and TP2.
  • q min ⁇ q ** ⁇ q max N min ⁇ N ⁇ N max (N min ⁇ N ⁇ N 0 ) become that way.
  • Load pressure of the boom cylinder 3a is further increased, if the discharge pressure of the main pump 2 becomes a pressure set value P pso more example P e, the controller 50, the arithmetic unit 50r, from the cut-off control characteristics TP3, calculating a cut-off control of the limit value q * limit the value of for example the point E between the point M and point N in FIG. 3 q * limits (values between q max and q * limit0).
  • the computing unit 50s outputs the smaller of the virtual capacity q * and q * limit as a new virtual capacity q **.
  • the calculation unit 50i limits the new virtual capacity q **, and the calculation units 50j to 50m calculate the command signal V INV of the inverter 60 from the virtual capacity q **. Is output.
  • the virtual capacity q ** is limited, so that the rotational speed of the electric motor 1 is low. It can be suppressed.
  • the main pump 2A operates at point E1 in FIG. 4, and the pump capacity (actual capacity) is qe.
  • the controller 50 is supplied with a pressure detection signal V PS for the pressure of the second pressure oil supply oil passage 4a by the pressure sensor 40 and a pressure detection signal V PLmax for the pressure of the signal oil passage 27 by the pressure sensor 41.
  • the pressures are equal and are the same as the relief pressure set by the relief valve 14.
  • the controller 50 increases or decreases the virtual capacity q * of the main pump 2 so that the pressure in the second pressure oil supply oil passage 4a is higher than the pressure in the signal oil passage 27 by the target LS differential pressure PGR.
  • the calculation unit 50r determines the cutoff control from the cutoff control characteristic TP3.
  • the virtual capacity limit value q * limit the value at the N point in FIG. 3, that is, the minimum value q * limit0 is calculated.
  • the computing unit 50s outputs the smaller of the virtual capacity q * and q * limit as a new virtual capacity q **.
  • the virtual capacity q ** is held at q * limit0.
  • the calculation unit 50i limits the new virtual capacity q **, and the calculation units 50j to 50m calculate the command signal V INV of the inverter 60 from the virtual capacity q **. Is output. Since the virtual volume q ** is q * limit0, target flow rate Q d calculated in the calculation unit 50j is also Qsmall close to Q min, the target rotational speed of the main pump 2 calculated in the calculation unit 50k N d is also Nsmall close to the N min. Thereby, the rotation speed of the electric motor 1 is suppressed to an extremely small value corresponding to Nsmall.
  • the hydraulic oil cooling system can be downsized.
  • the main pump 2 in addition to performing load sensing control and cut-off control by the motor speed control of the controller 50, the main pump 2 is provided with a torque control device 17, and the discharge pressure of the main pump 2 is maintained at the main pressure.
  • the pressure of the relief valve 14 is within the pressure range below the set value P pso near the set pressure P max (within the range of P 0 to P pso )
  • the discharge flow rate of the main pump 2 decreases as the discharge pressure of the main pump 2 increases.
  • the torque control for limiting the absorption torque of the main pump 2 is performed.
  • the horsepower consumed by the main pump 2 is suppressed by the torque control that limits the absorption torque of the main pump 2 even before the cutoff control by the motor rotation speed control starts. Since the power consumption of the electric motor 1 is reduced, the battery 70 that is the electric power source of the electric motor 1 can be further extended, and the operating time of the electric hydraulic working machine can be further extended. Moreover, since the power consumption of the electric motor 1 decreases, the electric motor 1 can be reduced in size.
  • FIG. 6A is a diagram showing the horsepower characteristics of a conventional hydraulic drive device that performs load sensing control by controlling the rotation speed of a fixed displacement hydraulic pump that does not include a torque control device
  • FIG. It is a figure which shows the horsepower characteristic of a hydraulic drive device. It is assumed that the capacity (constant) of the fixed displacement hydraulic pump in the conventional hydraulic drive device is the same q max as the maximum capacity of the main pump 2 in the present embodiment shown in FIG.
  • the displacement of the hydraulic pump remains constant at the maximum q max when the discharge pressure of the hydraulic pump reaches the maximum P max .
  • the discharge flow rate of the hydraulic pump becomes the maximum Q max
  • the consumed horsepower of the hydraulic pump is expressed by the product of the maximum discharge pressure P max and the maximum discharge flow rate Q max. It increases to the value (the area of the shaded area in FIG. 6A).
  • the output horsepower of the electric motor is increased to HM * corresponding to the consumed horsepower of the hydraulic pump.
  • the power consumption of the electric motor increases.
  • power consumption for cooling the motor also increases. Therefore, there is a problem in that the amount of discharge of a battery (power storage device) that is a power source of the electric motor increases, the battery is rapidly depleted, and the operation time of the work machine is shortened.
  • the torque control device 17 is provided with the main pump 2 as a variable displacement type, and “boom raising single operation (heavy load)” and As described in the operation example of “Boom raising single operation (at the time of relief)”, the absorption torque of the main pump is controlled so as not to exceed the maximum torque TM when the discharge pressure of the main pump 2 rises.
  • the torque limit control of the main pump 2 in this way, when the discharge pressure of the main pump 2 increases, the absorption torque of the main pump 2 is controlled to be equal to or less than the maximum torque TM, and the consumed horsepower of the main pump 2 is maximum.
  • Control is performed so as not to exceed the maximum horsepower HM obtained by multiplying the torque TM by the number of rotations of the main pump 2 at that time.
  • the horsepower consumed by the main pump 2 is suppressed, the output horsepower of the motor 1 is reduced to HM, and the power consumption of the motor 1 is reduced as compared with the case where load sensing control is performed by conventional motor speed control.
  • the battery 70 can last longer and the operating time of the electric hydraulic working machine can be extended.
  • the electric motor 1 can be reduced in size because the output horsepower of the electric motor 1 decreases.
  • ⁇ Effect 3> obtains a target flow rate Q d of the load sensing control by introducing the concept of virtual capacity q * of the hydraulic pump load sensing control arithmetic unit 50a ⁇ 50c of the controller 50, to 50f ⁇ 50h, the motor 1 Since the load sensing control is performed by controlling the rotational speed of the electric motor 1 by controlling the rotational speed of the motor 1, it is easy to incorporate other functions into the load sensing control.
  • the virtual capacity limit value q * limit of the cutoff control is calculated by the calculation unit 50r, and the virtual capacity calculated by the load sensing control calculation units 50a to 50c and 50f to 50h is calculated by the calculation unit 50s.
  • the controller 50 sets the reference rotation speed N 0 on the basis of an instruction signal V EC reference rotation speed instruction dial 51, and in accordance with the magnitude of the reference rotation speed N 0 on the basis of the reference rotational speed N 0 A target LS differential pressure PGR and a target flow rate Qd are calculated.
  • FIG. 7 is a diagram showing a configuration of a hydraulic drive device for an electric hydraulic work machine according to the second embodiment of the present invention. This embodiment is also a case where the present invention is applied to a hydraulic drive device of a front swing type hydraulic excavator.
  • the hydraulic drive apparatus is different from the first embodiment shown in FIG. 1 in that the main pump 2A is a fixed displacement type, and the main pump 2A is a torque control device 17 for controlling horsepower. Not equipped.
  • the controller 50A has a control function (function of a torque control device) for simulating horsepower control of the main pump 2A in addition to a control function for simulating cut-off control of the main pump 2A.
  • FIG. 8 is a functional block diagram showing the processing contents of the controller 50A.
  • the controller 50A includes a calculation unit 50Ar instead of the calculation unit 50r in the functional block diagram shown in FIG.
  • the calculation unit 50Ar has a table in which characteristics are set in which characteristics (torque control characteristics) that simulate torque control and characteristics (cutoff control characteristics) that simulate cutoff control are combined.
  • the discharge pressure P PS of the main pump 2A converted by the calculation unit 50a is input to the calculation unit 50Ar, and the calculation unit 50Ar refers to the discharge pressure P PS of the main pump 2A in the table and the corresponding virtual capacity limit value ( Maximum virtual capacity) q * limit is calculated.
  • FIG. 9 is a diagram showing characteristics obtained by combining characteristics (torque control characteristics) simulating torque control set in the arithmetic unit 50Ar and characteristics (cut-off control characteristics) simulating cut-off control.
  • FIG. 10 is a diagram showing the torque characteristics of the main pump 2A.
  • the capacity of the main pump 2A is constant over the entire range of the discharge pressure of the main pump 2A and is at the maximum capacity q max on the characteristic line TP0. Further, when the discharge pressure of the main pump 2A increases, the consumption torque of the main pump 2A increases linearly over the entire range of the discharge pressure.
  • Torque control characteristics set to the arithmetic unit 50Ar is a characteristic TP0r2 the discharge pressure of the main pump 2A corresponds to the characteristic line TP0 maximum capacity of the main pump 2A when less than P 0, the discharge pressure of the main pump 2A P
  • This is composed of a constant torque curve TP4 when it becomes 0 or more and a cutoff control characteristic TP5 when the discharge pressure of the main pump 2A exceeds the set value P pso .
  • the cutoff control characteristic TP5 indicates that the limit value q * limit is steep and linear from q * limit1 to the minimum value q * limit2 when the discharge pressure of the main pump 2A increases from the set value P pso to the maximum discharge pressure P max. It is set to be smaller.
  • the set value P pso is higher than the starting pressure P 0 (described later) of the constant absorption torque control, and is close to the maximum discharge pressure P max .
  • the limit value q * limit1 is a value on the constant torque curve TP4 when the discharge pressure of the main pump 2A is at the set value P pso .
  • the minimum value q * limit2 is a small volume close to the minimum capacity q min of the main pump 2A, for example, a minimum capacity q min.
  • the calculation unit 50s selects a smaller one of the virtual capacity q * of the load sensing control calculated by the calculation unit 50h and the limit value q * limit of the virtual capacity obtained by the calculation unit 50r as a new virtual capacity q **. Output.
  • the above-described function of the controller 50A, the inverter 60, and the pressure sensors 40 and 41 are similar to the first embodiment in that the discharge pressure of the main pump 2A is higher than the maximum load pressure of the actuators 3a, 3b, 3c.
  • Load sensing control for controlling the rotational speed of the main pump 2A so as to increase only when the discharge pressure of the main pump 2A rises above the first predetermined pressure P pso near the set pressure P max of the main relief valve 14
  • An electric motor rotation speed control device 200A that performs cut-off control for controlling the rotation speed of the main pump 2A so as to reduce the discharge flow rate of the pump 2A is configured.
  • the calculation units 50a to 50c and 50f to 50h of the controller 50A are based on the discharge pressure P PS and the maximum load pressure P PLmax of the main pump 2A detected by the pressure sensors 40 and 41, and the target LS differential pressure P GR .
  • the calculation unit 201 is configured.
  • the calculation units 50Ar and 50s of the controller 50A are configured to have a first predetermined pressure P pso that the discharge pressure of the main pump 2A is close to the set pressure P max of the main relief valve 14.
  • P pso the first predetermined pressure
  • a capacity limit control calculation unit 202A for obtaining the virtual capacity q ** is configured.
  • calculation units 50Ar and 50s of the controller 50A are incorporated in the controller 50A as a function of the controller 50A, and when the discharge pressure of the main pump 2A increases, the discharge flow rate of the main pump 2A is decreased to reduce the main pump 2A.
  • a torque control device is configured to control the absorption torque so as not to exceed a preset maximum torque.
  • the arithmetic unit 50aR, 50s based on the discharge pressure of the main pump 2A, the pressure sensor 40 detects the discharge pressure of the main pump 2A is at a second predetermined pressure P 0 or more, the set pressure P of the main relief valve 14 A virtual capacity limit value q * for torque limit control that decreases as the discharge pressure of the main pump 2A increases when the pressure is in a pressure range (in the range of P 0 to P pso ) that is less than the first predetermined pressure P pso near max .
  • the calculation units 50Ar, 50s calculate a virtual capacity limit value q * limit that decreases as the discharge pressure of the main pump 2A increases, and the load Torque limit control for selecting a smaller virtual capacity q * and virtual capacity limit value q * limit calculated by the sensing control calculation units (calculation units 50a to 50c, 50f to 50h) to obtain a new virtual capacity q ** It can also be said that it is a calculation part.
  • the calculation unit 50s selects the virtual capacity q * of the load sensing control calculated by the calculation unit 50h, and outputs this as a new virtual capacity q **.
  • the virtual capacity q ** is reduced to the minimum capacity q min by the limiting process of the calculation unit 50i, and the target flow rate Q d , the target rotation speed N d of the main pump 2A, and the command signal V INV of the inverter 60 are minimum. Value. Thereby, the rotation speed of the electric motor 1 is held at the minimum value, and the discharge flow rate of the main pump 2A is also held at the minimum value.
  • the main pump 2A operates at point A1 in FIG. 10, and the pump capacity (actual capacity) is q max (fixed).
  • the calculation unit 50s selects the virtual capacity q * of the load sensing control calculated by the calculation unit 50h, and outputs this as a new virtual capacity q **. .
  • the virtual capacity q ** increases or decreases in accordance with the operation amount (required flow rate) of the operation lever, and changes from the minimum to the maximum by the restriction process of the calculation unit 50i.
  • the rotational speed of the electric motor 1 (the rotational speed of the main pump 2A) similarly changes from the minimum to the maximum according to the operation amount (required flow rate) of the operation lever.
  • the main pump 2A operates at point B1 in FIG. 10, and the pump capacity (actual capacity) is q max (fixed).
  • the smaller one of the virtual capacity q * and the virtual capacity limit value q * limit is selected and output as a new virtual capacity q **. That is, when q * ⁇ q * limit, q * is selected, and when q *> q * limit, q * limit is selected, and these are output as new virtual capacity q **.
  • the virtual capacity q ** is limited to q * limit
  • the target flow rate Q d the target rotational speed N d of the main pump 2A, and the command signal V INV of the inverter 60 are similarly limited, and the electric motor 1 The rotation speed is limited.
  • the controller 50 has a control function having the same function as the torque control device 17 in the first embodiment, and is controlled so that the absorption torque of the main pump 2A does not exceed the maximum torque (limit torque) TM.
  • the main pump 2A operates at a point C3 in FIG. 10, and the pump capacity (actual capacity) is q max (fixed).
  • Load pressure of the boom cylinder 3a is further increased, if the discharge pressure of the main pump 2A becomes the pressure set value P pso more example P f, the controller 50, the computing section 50aR, from the cut-off control characteristic TP5, The value q * limitf at the point F between the points P and Q in FIG. 9 is calculated as the limit value q * limit for the cutoff control. Subsequently, the computing unit 50s outputs the smaller of the virtual capacity q * and q * limit as a new virtual capacity q **. Subsequently, the calculation unit 50i limits the new virtual capacity q **, and the calculation units 50j to 50m calculate the command signal V INV of the inverter 60 from the virtual capacity q **. Is output.
  • the target flow rate Q d the target rotational speed N d of the main pump 2A, and the command signal V INV of the inverter 60 are similarly minimum values.
  • the number of rotations of the electric motor 1 is limited to the minimum N min .
  • the discharge pressure of the main pump 2A increases, the consumed horsepower of the main pump 2A is suppressed by the torque control based on the motor rotational speed control even before the cutoff control based on the motor rotational speed control is started. Since power consumption is reduced, the battery 70 that is the power source of the electric motor 1 can be further extended, and the operating time of the electric hydraulic work machine can be further extended. Moreover, since the power consumption of the electric motor 1 decreases, the electric motor 1 can be reduced in size.
  • the pressure compensating valves 7a, 7b, 7c,... are arranged on the downstream side of the meter-in restricting portions of the flow control valves 6a, 6b, 6c, and all the flow control valves 6a, 6b, 6c,.
  • the downstream pressure of the flow control valves 6a, 6b, 6c... Is controlled to the same differential pressure by controlling the downstream pressure to the same maximum load pressure, but the flow control valves 6a, 6b, 6c. It may be a front-end type that is arranged upstream of the meter-in throttle and controls the differential pressure across the meter-in throttle to a set value.
  • a construction machine other than a hydraulic excavator for example, a hydraulic crane
  • a construction machine other than a hydraulic excavator for example, a hydraulic crane
  • it is a work machine that drives a plurality of actuators based on oil discharged from the main pump.
  • a similar effect can be obtained by applying the present invention to a wheel excavator or the like.

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  • Operation Control Of Excavators (AREA)

Abstract

En plus d'effectuer une commande à détection de charge d'une pompe principale (2) par commande de la fréquence de rotation d'un moteur électrique (1) à l'aide d'un dispositif de commande (50), une commande d'interruption servant à commander la fréquence de rotation de la pompe principale (2) est effectuée de manière à réduire le débit de sortie de la pompe principale (2) lorsque la pression de sortie de la pompe principale (2) monte au-dessus d'une première pression spécifiée (Ppso) près de la pression de consigne (Pmax) d'une soupape de décharge principale (14). En conséquence, dans l'équipement hydraulique électrique, qui entraîne la pompe hydraulique à l'aide du moteur électrique pour entraîner un actionneur et effectuer une commande à détection de charge par commande de la fréquence de rotation du moteur électrique, la consommation d'énergie perdue par le fonctionnement de la soupape de décharge est limitée, des élévations brusques de la fréquence de rotation du moteur électrique sont limitées et une efficacité et un confort plus élevés peuvent être garantis.
PCT/JP2013/081795 2012-11-27 2013-11-26 Dispositif d'entraînement hydraulique d'équipement hydraulique électrique WO2014084213A1 (fr)

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CN201380046824.6A CN104619996B (zh) 2012-11-27 2013-11-26 电动式液压作业机械的液压驱动装置

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Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2019186841A1 (fr) * 2018-03-28 2019-10-03 株式会社日立建機ティエラ Dispositif d'entraînement hydraulique pour engin de chantier
JP2021042602A (ja) * 2019-09-12 2021-03-18 住友建機株式会社 ショベル
JPWO2021059337A1 (fr) * 2019-09-24 2021-04-01
CN113027870A (zh) * 2021-03-17 2021-06-25 四川百纳科技有限责任公司 一种全地形装甲车独立散热系统及其控制方法
CN113508207A (zh) * 2019-03-29 2021-10-15 住友建机株式会社 挖土机

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP6858723B2 (ja) * 2018-03-28 2021-04-14 日立建機株式会社 ホイールローダ
US10947702B2 (en) * 2018-09-05 2021-03-16 Hitachi Construction Machinery Tierra Co., Ltd Hydraulic drive system for electrically driven hydraulic work machine
EP3940151B1 (fr) * 2019-03-11 2024-04-24 Sumitomo Construction Machinery Co., Ltd. Pelle excavatrice
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CN110512686B (zh) * 2019-08-02 2022-03-04 江苏恒立液压科技有限公司 电控液压控制系统和具有其的工程机械

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2003074505A (ja) * 2001-08-30 2003-03-12 Mitsubishi Heavy Ind Ltd 射出成形機、射出成形機の液圧作動機構及びその制御方法
JP2003172302A (ja) * 2001-12-06 2003-06-20 Yuken Kogyo Co Ltd インバータ駆動油圧ユニット
JP2004036421A (ja) * 2002-07-01 2004-02-05 Nikuni:Kk 液供給方法および液供給装置
JP2008256037A (ja) * 2007-04-03 2008-10-23 Hitachi Constr Mach Co Ltd 電動式油圧作業機
JP2008256224A (ja) * 2008-07-31 2008-10-23 Daishin Shoko:Kk 可変ピストンポンプを油浸状態で使用した油圧源分散型油圧ユニット
JP2009255476A (ja) * 2008-04-21 2009-11-05 Meiki Co Ltd 射出成形機

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
IN171213B (fr) * 1988-01-27 1992-08-15 Hitachi Construction Machinery
JP3115887B2 (ja) * 1990-09-28 2000-12-11 株式会社小松製作所 クローズドセンタ・ロードセンシングシステムにおけるポンプの吐出容積の可変回路
JPH08135606A (ja) * 1994-11-10 1996-05-31 Shin Caterpillar Mitsubishi Ltd 油圧ポンプの吐出量制御装置
CN1170068C (zh) * 2002-04-23 2004-10-06 浙江大学 工程机械中多执行器运动的电液数字分流控制系统
JP2007024103A (ja) * 2005-07-13 2007-02-01 Hitachi Constr Mach Co Ltd 油圧駆動装置
CN201896601U (zh) * 2010-11-23 2011-07-13 宝鸡宝石特种车辆有限责任公司 固井水泥车多路负载敏感液压传动系统

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2003074505A (ja) * 2001-08-30 2003-03-12 Mitsubishi Heavy Ind Ltd 射出成形機、射出成形機の液圧作動機構及びその制御方法
JP2003172302A (ja) * 2001-12-06 2003-06-20 Yuken Kogyo Co Ltd インバータ駆動油圧ユニット
JP2004036421A (ja) * 2002-07-01 2004-02-05 Nikuni:Kk 液供給方法および液供給装置
JP2008256037A (ja) * 2007-04-03 2008-10-23 Hitachi Constr Mach Co Ltd 電動式油圧作業機
JP2009255476A (ja) * 2008-04-21 2009-11-05 Meiki Co Ltd 射出成形機
JP2008256224A (ja) * 2008-07-31 2008-10-23 Daishin Shoko:Kk 可変ピストンポンプを油浸状態で使用した油圧源分散型油圧ユニット

Cited By (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPWO2019186841A1 (ja) * 2018-03-28 2020-04-30 株式会社日立建機ティエラ 建設機械の油圧駆動装置
EP3591239A4 (fr) * 2018-03-28 2021-01-06 Hitachi Construction Machinery Tierra Co., Ltd. Dispositif d'entraînement hydraulique pour engin de chantier
WO2019186841A1 (fr) * 2018-03-28 2019-10-03 株式会社日立建機ティエラ Dispositif d'entraînement hydraulique pour engin de chantier
US11214940B2 (en) 2018-03-28 2022-01-04 Hitachi Construction Machinery Tierra Co., Ltd. Hydraulic drive system for construction machine
CN113508207A (zh) * 2019-03-29 2021-10-15 住友建机株式会社 挖土机
JP2021042602A (ja) * 2019-09-12 2021-03-18 住友建機株式会社 ショベル
JP7396838B2 (ja) 2019-09-12 2023-12-12 住友建機株式会社 ショベル
CN113994092A (zh) * 2019-09-24 2022-01-28 株式会社日立建机Tierra 电动式液压作业机械
WO2021059337A1 (fr) * 2019-09-24 2021-04-01 株式会社日立建機ティエラ Machine de travail hydraulique électrique
JP7261894B2 (ja) 2019-09-24 2023-04-20 株式会社日立建機ティエラ 電動式油圧作業機械
JPWO2021059337A1 (fr) * 2019-09-24 2021-04-01
CN113994092B (zh) * 2019-09-24 2024-06-04 株式会社日立建机Tierra 电动式液压作业机械
CN113027870A (zh) * 2021-03-17 2021-06-25 四川百纳科技有限责任公司 一种全地形装甲车独立散热系统及其控制方法
CN113027870B (zh) * 2021-03-17 2022-10-18 四川百纳科技有限责任公司 一种全地形装甲车独立散热系统及其控制方法

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