WO2000065239A1 - Procede et dispositif de commande d'un engin de construction - Google Patents

Procede et dispositif de commande d'un engin de construction Download PDF

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Publication number
WO2000065239A1
WO2000065239A1 PCT/JP2000/002441 JP0002441W WO0065239A1 WO 2000065239 A1 WO2000065239 A1 WO 2000065239A1 JP 0002441 W JP0002441 W JP 0002441W WO 0065239 A1 WO0065239 A1 WO 0065239A1
Authority
WO
WIPO (PCT)
Prior art keywords
control
hydraulic
hydraulic oil
stick
pump
Prior art date
Application number
PCT/JP2000/002441
Other languages
English (en)
Japanese (ja)
Inventor
Kimimasa Onda
Original Assignee
Shin Caterpillar Mitsubishi Ltd.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Shin Caterpillar Mitsubishi Ltd. filed Critical Shin Caterpillar Mitsubishi Ltd.
Publication of WO2000065239A1 publication Critical patent/WO2000065239A1/fr

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Classifications

    • 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
    • E02F9/2221—Control of flow rate; Load sensing arrangements
    • E02F9/2239—Control of flow rate; Load sensing arrangements using two or more pumps with cross-assistance
    • E02F9/2242—Control of flow rate; Load sensing arrangements using two or more pumps with cross-assistance 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
    • E02F9/226—Safety arrangements, e.g. hydraulic driven fans, preventing cavitation, leakage, overheating
    • 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
    • E02F9/2282—Systems using center bypass type changeover valves
    • 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
    • E02F9/2292—Systems with two or more pumps
    • 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
    • F15B11/17—Servomotor systems without provision for follow-up action; Circuits therefor with two or more servomotors using two or more pumps
    • 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
    • F15B21/00—Common features of fluid actuator systems; Fluid-pressure actuator systems or details thereof, not covered by any other group of this subclass
    • F15B21/14—Energy-recuperation 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
    • F15B2211/20—Fluid pressure source, e.g. accumulator or variable axial piston pump
    • F15B2211/205—Systems with pumps
    • F15B2211/2053—Type of pump
    • F15B2211/20546—Type of pump variable capacity
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/20—Fluid pressure source, e.g. accumulator or variable axial piston pump
    • F15B2211/205—Systems with pumps
    • F15B2211/20576—Systems with pumps with multiple pumps
    • 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
    • F15B2211/50—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
    • F15B2211/50518—Pressure control characterised by the type of pressure control means the pressure control means controlling a pressure upstream of the pressure control means using pressure relief 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
    • F15B2211/50—Pressure control
    • F15B2211/515—Pressure control characterised by the connections of the pressure control means in the circuit
    • F15B2211/5156—Pressure control characterised by the connections of the pressure control means in the circuit being connected to a return line and a 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
    • F15B2211/50—Pressure control
    • F15B2211/55—Pressure control for limiting a pressure up to a maximum pressure, e.g. by using a pressure relief 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
    • F15B2211/60—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
    • F15B2211/63—Electronic controllers
    • F15B2211/6303—Electronic controllers using input signals
    • F15B2211/633—Electronic controllers using input signals representing a state of the prime mover, e.g. 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
    • F15B2211/635—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
    • F15B2211/6652—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
    • F15B2211/7142—Multiple output members, e.g. multiple hydraulic motors or cylinders the output members being arranged in multiple groups

Definitions

  • the present invention relates to a control device and a control method for a construction machine, which control the operation of a hydraulic machine such as a boom cylinder and a stick cylinder in the construction machine.
  • a construction machine such as a hydraulic excavator includes an upper rotating body 102, a lower traveling body 100, and a working device 118 as shown in FIG.
  • the undercarriage 100 has a right track 100R and a left track 100L that can be driven independently of each other, while the upper revolving structure 102 has a lower track 100 On the other hand, it is provided so as to be pivotable in a horizontal plane.
  • the working device 118 mainly includes a boom 103, a stick 104, a bucket 108, and the like, and the boom 103 rotates with respect to the upper rotating body 102. It is pivoted as much as possible.
  • a stick 104 is connected to the tip of the boom 103 so as to be rotatable in the same vertical plane.
  • a boom drive hydraulic cylinder (boom cylinder, hydraulic actuator) 105 for driving the boom 103 is provided between the upper swing body 102 and the boom 103.
  • a hydraulic cylinder (stick cylinder, hydraulic actuator) 106 for driving the stick 104 is provided between the boom 103 and the stick 104.
  • a bucket driving hydraulic cylinder (bucket) for driving the bucket 108. Cylinders and hydraulic actuators) 107 are provided.
  • Each of the cylinders 105 to 107 described above includes a hydraulic pump driven by an engine (mainly a diesel engine), a control valve for a boom, a control valve for a stick, a control valve for a bucket, and the like.
  • a hydraulic circuit (not shown) having a plurality of control valves is connected, and hydraulic oil of a predetermined hydraulic pressure is supplied from a hydraulic pump via each control valve, and according to the hydraulic pressure supplied in this manner. It is designed to be driven.
  • the boom 103 is in the directions a and b in the figure
  • the stick 104 is in the directions c and d in the figure
  • the bracket 107 is in the direction e in the figure.
  • f is rotatable.
  • the rotation of the boom 103 in the direction b in the figure is called boom down
  • the rotation of the stick 104 in the direction d in the figure is called stick-in.
  • the operating room 101 has left and right levers as operating members for controlling the operation of the hydraulic excavator (running, turning, boom turning, stick turning, and bucket turning). , Left pedal, right pedal, etc. are provided.
  • each control valve of the hydraulic circuit is controlled, and each cylinder 105 to 107 is driven.
  • 03, stick 104 and bucket 108 can be rotated.
  • a pilot hydraulic circuit is provided to control each control valve.
  • the pilot hydraulic pressure is applied to the boom through the pilot oil passage.
  • Control valve ⁇ Acts on the stick control valve to drive the boom control valve and the stick control valve to the required positions.
  • the boom drive hydraulic cylinder 1 0 5 Supply and discharge of hydraulic oil to and from the hydraulic cylinders 106 are controlled, and these cylinders 105 and 106 are driven to expand and contract to the required length.
  • the excavation work and the like are performed by driving the working devices 1 18 such as the booms 103 and the sticks 104 by driving the cylinders 105 to 107 to expand and contract. Of various operations.
  • the stick driving hydraulic cylinder 106 may be extended.
  • the pilot oil pressure is applied to the stick control valve through the pilot oil passage.
  • the spool position of the stick control valve becomes the stick lowered position, and the hydraulic oil from the hydraulic pump is supplied to one chamber of the stick driving hydraulic cylinder 106 through the oil passage.
  • the hydraulic oil in the other room of the stick driving hydraulic cylinder 106 is discharged to the tank through the oil passage.
  • the stick driving hydraulic cylinder 106 is extended, and the stick 104 is rotated downward as shown by the arrow d in FIG.
  • a throttle is interposed in the oil passage between the stick driving hydraulic cylinder 106 and the reservoir tank in order to prevent the stick driving hydraulic cylinder 106 from dropping sharply. Hydraulic oil discharged from the hydraulic cylinder 106 is prevented from being discharged to the reservoir tank more than necessary.
  • the diameter of these throttles is particularly low when the engine speed is low and the pump discharge flow rate is low, so that each cylinder communicates with the reservoir tank so that hydraulic oil is not excessively discharged from the cylinders 105 to 107.
  • the opening area of the oil passage (hydraulic oil discharge passage) is set to be small.
  • the stick drive hydraulic cylinder 106 and the reservoir tank When the stick drive hydraulic cylinder 106 is lowered using gravity when stick-in operation is performed, the diameter of the throttle interposed in the oil passage between The back pressure acting to push back the hesitic hydraulic cylinder 106 in the direction opposite to the direction of gravity drop of the cylinder 106 is about 40 kgf / under the specified reference load (load) condition. It is set to be about cm 2 .
  • a predetermined pressure (about 40 kgf Z cm 2 ) is applied to the stick drive hydraulic cylinder 106.
  • the oil passage between the hydraulic cylinder 106 for driving the stick and the reservoir tank increases.
  • back pressure (approximately 145 kgf Z cm 2 ) acts on the hydraulic cylinder 106 for the stick drive, causing the hydraulic cylinder 106 for the stick drive to gravity.
  • extra pressure from the hydraulic pump (pump discharge pressure) corresponding to the back pressure shown in the following equation is required.
  • Pressure from hydraulic pump (actual back pressure-predetermined pressure) X cylinder area ratio This is the same for the boom driving hydraulic cylinder 105 and the bucket driving hydraulic cylinder 107.
  • the present invention has been made in view of such a problem, and aims to improve the working efficiency at the time of controlling the self-weight drop of the hydraulic actuator, reduce power loss, improve fuel efficiency, reduce heat loss, and improve cooling performance. It is an object of the present invention to provide a control device and a control method for a construction machine, which can be improved. Disclosure of the invention
  • the control device for a construction machine of the present invention is driven by an operating member operated by an operator, a hydraulic pump driven by an engine to discharge hydraulic oil in a tank, and a hydraulic oil discharged by a hydraulic pump.
  • a control that controls the flow rate of hydraulic oil that is interposed in the hydraulic oil discharge passage, the hydraulic oil discharge passage that discharges hydraulic oil from the hydraulic oil pump to the tank, and the hydraulic oil discharge passage.
  • Detects valve and engine speed An engine speed sensor; and control means for controlling a control valve to adjust an opening area of the hydraulic oil discharge passage based on an operation amount of an operation member, wherein the control means is detected by the engine speed sensor.
  • the control valve is controlled in consideration of the engine speed.
  • a hydraulic oil supply passage for supplying hydraulic oil from the hydraulic pump to the hydraulic actuator is provided, and the opening area of the hydraulic oil discharge passage is detected by the engine rotation speed sensor with the maximum operation amount of the operating member. It is preferable that a setting is made such that when the engine rotation speed is at a maximum, a hydraulic oil having a flow rate corresponding to the maximum supply flow rate of the hydraulic oil supplied through the hydraulic oil supply passage is discharged through the hydraulic oil discharge passage.
  • control means may be configured to control the control valve so that the opening area of the hydraulic oil discharge passage decreases as the engine rotation speed detected by the engine rotation speed sensor decreases.
  • control means may be configured to correct the control amount for the control valve by a correction coefficient that decreases as the engine speed decreases.
  • control means may be configured to set the control amount of the control valve such that the opening area of the hydraulic oil discharge passage changes according to the engine speed.
  • a bypass passage is provided for returning hydraulic oil not supplied to the hydraulic actuator to the tank via the control valve to the tank, and the control valve is interposed in the bypass passage to adjust the opening area of the bypass passage.
  • the control means sets a basic tilt angle control amount for controlling a basic tilt angle control amount for controlling the discharge flow rate from the hydraulic pump based on a characteristic substantially inversely proportional to the flow rate of the hydraulic oil in the bypass passage.
  • a tilt angle control amount correction means for correcting the basic tilt angle control amount set by the basic tilt angle control amount setting means so that the discharge flow rate from the hydraulic pump is maximized. Is preferred.
  • the construction machine control method of the present invention includes an operation member operated by an operator, a hydraulic pump driven by an engine to discharge hydraulic oil in a tank, and a hydraulic pump discharged by a hydraulic pump.
  • Hydraulic oil pump a hydraulic oil discharge passage that discharges hydraulic oil from the hydraulic oil pump to the tank, and a hydraulic oil discharge passage that is interposed in the hydraulic oil discharge passage and controls the flow rate of hydraulic oil that is discharged through the hydraulic oil discharge passage.
  • a construction valve comprising: a control valve; an engine speed sensor for detecting an engine speed; and control means for controlling the control valve to adjust an opening area of the hydraulic oil discharge passage based on an operation amount of an operation member.
  • a control method comprising: a detection step for detecting an engine speed by an engine speed sensor; and an engine speed detected in the detection step. And a control step of controlling the control valve by the control means.
  • the hydraulic oil supply passage that supplies the hydraulic oil from the hydraulic pump to the hydraulic actuator.
  • the control valve is controlled such that the hydraulic oil at a flow rate corresponding to the maximum supply flow rate of the hydraulic oil supplied through the hydraulic oil discharge passage is discharged through the hydraulic oil discharge passage.
  • control valve is controlled such that the opening area of the hydraulic oil discharge passage decreases as the engine rotation speed detected in the detection step decreases.
  • control amount for the control valve is corrected by a correction coefficient that decreases as the engine rotation speed decreases. It is also preferable that in the control step, the control amount of the control valve is set such that the opening area of the hydraulic oil discharge passage changes in accordance with the engine speed.
  • a bypass passage is provided for returning hydraulic oil not supplied to the hydraulic actuator through the control valve to the tank, and the control valve is interposed in the bypass passage to adjust the opening area of the bypass passage.
  • a basic tilt angle control amount for controlling the discharge flow rate from the hydraulic pump is set based on a characteristic substantially inversely proportional to the flow rate of the hydraulic oil in the bypass passage, and the operation member is operated.
  • the amount is maximum and the engine rotation speed detected in the detection step is not maximum, it is also preferable to correct the basic tilt angle control amount so that the discharge flow rate from the hydraulic pump becomes maximum.
  • the excess horsepower consumption during the descent of the hydraulic actuator during its own weight reduction is reduced, so that power loss is reduced, fuel consumption is improved, and heat The loss can be reduced. Also, since the pressure in the hydraulic actuator does not increase and the temperature in the hydraulic actuator does not increase, the heat balance can be improved and the cooling performance can be improved. Furthermore, there is no need for extra horsepower because no extra back pressure is generated when the deadweight of Hydraulic Factory is lowered. Work efficiency is improved.
  • FIG. 1 is a control block diagram for explaining the self-weight drop control of a stick in the control device for a construction machine according to one embodiment of the present invention.
  • FIG. 2 is an overall configuration diagram of a control device for a construction machine according to one embodiment of the present invention.
  • FIG. 3 is a schematic diagram for explaining a control valve of the control device for a construction machine according to one embodiment of the present invention.
  • FIG. 4 is a diagram showing a map associating an operation amount of an operation member and a basic control signal of a proportional pressure reducing valve in the control device for a construction machine according to one embodiment of the present invention.
  • FIG. 5 is a diagram showing a map in which the engine rotation speed and the control signal rate of the proportional pressure reducing valve are related in the control device for the construction machine according to the embodiment of the present invention.
  • FIG. 6 is a diagram showing a map in which the correction control signal and the spool stroke are related in the control device for the construction machine according to the embodiment of the present invention.
  • FIG. 7 is a diagram showing the relationship between the spool stroke amount and the opening areas of the PC passage, the CT passage, and the bypass passage in the control device for the construction machine according to the embodiment of the present invention.
  • FIG. 8 is a diagram showing control characteristics of the CT opening area according to the engine rotation speed in the control device for a construction machine according to one embodiment of the present invention.
  • FIG. 9 is a diagram illustrating a modification of the control characteristic of the CIT opening area according to the engine rotation speed in the control device for a construction machine according to one embodiment of the present invention.
  • FIG. 10 is a diagram showing a relationship between a required flow rate of negative flow control and a negative control pressure in the control device for a construction machine according to one embodiment of the present invention.
  • FIG. 11 is a diagram showing the relationship between the allowable flow rate of the negative flow control and the pump discharge pressure in the control device for a construction machine according to one embodiment of the present invention.
  • FIG. 12 is a flowchart for explaining the tilt angle control by the basic tilt angle control amount setting means of the control device for the construction machine according to one embodiment of the present invention. It is.
  • FIG. 13 is a flowchart for explaining the tilt angle correction control by the tilt angle control amount correction means of the control device for a construction machine according to one embodiment of the present invention.
  • FIG. 14 is a diagram showing a relationship between an engine rotation speed and a C-T opening area in the control device for a construction machine according to one embodiment of the present invention.
  • FIG. 15 is a diagram illustrating a relationship between an engine rotation speed and a back pressure in the control device for a construction machine according to one embodiment of the present invention.
  • FIG. 16 is a schematic perspective view showing a conventional construction machine.
  • FIG. 17 is a diagram showing the relationship between the engine rotation speed and the C-T opening area in a conventional construction machine control device.
  • FIG. 18 is a diagram showing the relationship between the engine rotation speed and the back pressure in a conventional construction machine control device.
  • This construction machine is a construction machine (working machine) such as a hydraulic shovel, as described in the related art (see FIG. 16), and includes an upper revolving unit 102, a lower traveling unit 100, and a working device. Consists of 1 1 8
  • the undercarriage 100 has a right track 100R and a left track 100L that can be driven independently of each other, while the upper revolving structure 102 has a lower track 100 On the other hand, it is provided so as to be pivotable in a horizontal plane.
  • the working device 118 mainly includes a boom 103, a stick 104, a socket 108, and the like.
  • the boom 103 rotates with respect to the upper rotating body 102. It is pivoted as much as possible.
  • a stick 104 is rotatably connected in the vertical plane.
  • a boom drive hydraulic cylinder (boom cylinder, hydraulic actuator) 105 for driving the boom 103 is provided between the upper rotating body 102 and the boom 103.
  • a stick driving hydraulic cylinder (stick cylinder, hydraulic actuator) 106 for driving the stick 104 is provided between the boom 103 and the stick 104.
  • a bucket driving hydraulic cylinder (bucket cylinder, hydraulic actuator) 107 for driving the bucket 108 is provided between the stick 104 and the bucket 108.
  • the boom 103 is in the directions a and b in the figure
  • the stick 104 is in the directions c and d in the figure
  • the baggage 108 is the direction e and f in the figure. It is configured to be rotatable in the direction.
  • FIG. 2 is a diagram schematically showing a main part of a hydraulic circuit of such a hydraulic shovel.
  • the left track 100 L and the right track 100 are identical as shown in FIG. 2, the left track 100 L and the right track 100
  • R is provided with a driving motor 109 L and 109 R as independent power sources, and the upper revolving unit 102 is provided with an upper revolving unit with respect to the lower traveling unit 100.
  • a turning motor 110 for turning the 102 is turned is provided.
  • These traveling motors 110 L and 109 R and turning motors 110 are configured as hydraulic motors that are operated by hydraulic pressure.
  • engines mainly diesel engines
  • Hydraulic oil from a plurality (here, two) of hydraulic pumps 51, 52 driven by 50 is supplied at a predetermined pressure via a hydraulic circuit 53, and the operation supplied in this manner is performed.
  • Each hydraulic motor 109L, 109R, 110 is driven according to the hydraulic pressure.
  • the hydraulic pumps 51 and 52 discharge the hydraulic oil in the reservoir tank 70 as a predetermined oil pressure.
  • a swash plate rotary piston pump piston type variable displacement pump, variable discharge amount type piston
  • Pump can adjust the pump discharge flow rate by changing the stroke amount of a piston (not shown) provided in the hydraulic pump.
  • one end of the piston is configured to abut on a swash plate (cleave plate: not shown), and the inclination (tilt angle) of the swash plate will be described later.
  • the inclination of the swash plate can be changed based on the operation signal from the controller 1.
  • each operation member 5 by the operator is changed. Because the amount of operation in 4 can also be taken into account, the operating feeling during operation can be improved compared to the conventional method in which the pressure of the hydraulic oil in the oil passage is guided to change the inclination of the swash plate. Can be done.
  • the engine 50 allows the operator to set the engine speed by switching the engine speed setting dial.
  • the maximum engine speed for example, about 200 rpm
  • the minimum engine speed are set. It can be switched in multiple stages between the engine rotation speed (for example, about 1000 rpm).
  • the engine speed is not limited to such a stepwise switching, but may be a type that can be changed smoothly.
  • the total horsepower of the engine 50 is consumed for driving these hydraulic pumps 51 and 52 and a later-described pilot pump 83.
  • the operation room 101 has a left lever, a right lever, a left pedal, and a left lever for controlling the operation of the hydraulic excavator (running, turning, boom turning, stick turning, and baguette turning).
  • a plurality of operating members 54 such as a right pedal are provided. These operation members 54 are configured as electric operation members (for example, electric operation levers), and output an electric signal corresponding to the operation amount to a controller (control means) 1 described later.
  • the hydraulic circuit 53 includes a first circuit unit 55 and a second circuit unit 56.
  • the first circuit section 55 is an oil passage connected to the first hydraulic pump 51.
  • the hydraulic oil from the first hydraulic pump 51 is supplied to the right traveling motor 110 R via the oil passage 61, the right traveling motor evening control valve 57, and the right traveling motor 110 R is driven.
  • the first hydraulic pump 5 1 These hydraulic oils are supplied to the packet driving hydraulic cylinder 107 via the oil passage 61 and the baguette control valve 58, and the oil passage 61 and the first boom control valve 59 To the boom drive hydraulic cylinder 105 through the oil passage 61 and the second stick control valve 60 to the stick drive hydraulic cylinder 106. Each cylinder 105, 106, 107 is driven.
  • a throttle (throttle with a relief valve) 81 is provided downstream of the oil passage 61 of the first circuit portion 55, and hydraulic fluid from the first hydraulic pump 51 is supplied to the reservoir through the throttle 81. It returns to tank 70.
  • the second circuit portion 56 includes an oil passage 66 connected to the second hydraulic pump 52, a left traveling motor control valve 62 interposed in the oil passage 66, and a turning motor evening control valve 6. 3, a control valve such as a first stick control valve 64, a second boom control valve 65, etc., and a throttle 82.
  • the hydraulic oil from the second hydraulic pump 52 is supplied to the left traveling motor 109 L via the oil passage 66 and the left traveling motor control valve 62, whereby the left traveling motor 90 109 L is driven.
  • Hydraulic oil from the second hydraulic pump 52 is supplied to the turning motor 110 via the oil passage 66 and the turning motor control valve 63, whereby the turning motor 110 Are driven.
  • the hydraulic oil from the second hydraulic pump 52 is supplied to the hydraulic cylinder 106 for driving the stick via the oil passage 66 and the control valve 64 for the first stick.
  • a throttle (a throttle with a relief valve) 82 is provided on the downstream side of the oil passage 66 of the second circuit portion 56, and the hydraulic oil from the second hydraulic pump 52 is provided through the throttle 82. It returns to the reservoir tank 70.
  • the control valves 57 to 60 and 62 to 65 are housed in a control unit (not shown).
  • the second stick is set so that a sufficient hydraulic oil is supplied to the important stick 104 in the operation of the construction machine even at the same time when the other work machine 118 is operated simultaneously.
  • the hydraulic oil from the first hydraulic pump 51 in the first circuit section 55 is also supplied to the stick driving hydraulic cylinder 106. It has become.
  • the first stick control valve 64 is interposed in the oil passage 66 of the second circuit portion 56, and the second stick control valve 60 is interposed in the oil passage 61 of the first circuit portion 55. Is equipped. Then, the first stick control valve 64 is controlled by the proportional control valves 64 a and 64 b, and the second stick control valve 60 is controlled by the proportional control valves 60 a and 60 b.
  • hydraulic oil can be supplied to and discharged from the hydraulic cylinder 106 for driving the stick.
  • sufficient operation for the boom In order to supply hydraulic oil, in addition to the hydraulic oil from the first hydraulic pump 51 in the first circuit section 55, the hydraulic oil from the second hydraulic pump 52 in the second circuit section 56 is also boom driven.
  • the first boom control valve 5 9 is via instrumentation to the oil passage 61 of the first circuit portion 5 5, the second circuit section 5 6
  • the second boom control valve 65 is interposed in the oil passage 66 of the second boom.
  • the first boom control valve 59 is controlled by the proportional control valves 59a and 59b
  • the second boom control valve 65 is controlled by the proportional control valves 65a and 65b.
  • the hydraulic oil can be supplied to and discharged from the boom drive hydraulic cylinder 105.
  • a stick regeneration valve 76 is interposed in the oil passages 67, 68 for supplying and discharging hydraulic oil to and from the hydraulic cylinder 106 for driving the stick.
  • a predetermined amount of hydraulic oil from the side oil passage to the hydraulic oil supply side oil passage Can be played.
  • boom regeneration valves 77 are also interposed in the oil passages 78, 799 that supply and discharge hydraulic oil to the boom drive hydraulic cylinder 105, and operate from the hydraulic oil discharge side oil passage. A predetermined amount of hydraulic oil can be regenerated to the oil supply side oil passage.
  • each of the control valves 57 to 60 and 62 to 65 is configured as a spool valve as shown in Fig. 3, and each is configured with a plurality of (here, five) throttles. .
  • control valves 57 to 60 and 62 to 65 are connected to the first hydraulic pump 51, the second hydraulic pump 52, and the stick driving hydraulic cylinder 106, respectively.
  • the stick control valves 60 and 64 are in the stick lowered position, but the stick control valves 60 and 64 are moved upward in FIG.
  • the stick control valves 60 and 64 can be set to the neutral position.
  • the P-C throttle 8 of the stick control valves 60 and 64 passes through the P-C passages 61a and 66a.
  • the C-T throttle 9 of the stick control valves 60 and 64 is interposed in the C-T passages 66 b and 69 to control the stick control valves 60 and 64.
  • the pump flow rate becomes maximum at the maximum engine rotation speed, and even when the operating member is fully operated, the pump is not excessively throttled by the C-T throttle 9 and is adjusted according to the maximum pump flow rate.
  • the diameter of the C-T throttle 9 is set to be sufficiently larger than that of the conventional one so that the hydraulic oil with the adjusted flow rate can be smoothly and surely discharged through the C_T passages 66b and 69. You.
  • the C-T opening area depends on the flow rate of the hydraulic oil supplied through the P-C passages 6 la and 66 a when the operation amount of the operation member 54 is the maximum and the engine rotation speed is the maximum. It is set so that the hydraulic fluid with the reduced flow rate is discharged through the C-T passages 66b and 69.
  • the cross-sectional area ratio is taken into account.
  • the flow rate of hydraulic oil supplied from the P_C passages 61 a and 66 a into the head-side oil chamber of the hydraulic cylinder 106 for stick drive, and the rod of hydraulic cylinder 106 for stick drive The ratio of the flow rate of the hydraulic oil discharged from the side oil chamber to the C-T passages 66 b and 69 depends on the cross-sectional area of the head side oil chamber of the hydraulic cylinder 106 for stick drive and the lock. It is obtained by taking into account the ratio to the cross-sectional area of the oil chamber on the pressure side, and the CT opening area, that is, the diameter of the CT throttle 9, is set accordingly.
  • the cross-sectional area (ie, volume) of each oil chamber is different, and the volume of hydraulic oil in the oil chamber on the rod side is smaller than the volume of hydraulic oil in the oil chamber on the head side.
  • each operating member When setting the diameters of the apertures 8, 9, and 10, each operating member is fully operated to ensure the interlocking of the working devices 118 such as the boom 103 and the stick 104. In this case, all working devices 1 18 are taken into account.
  • the opening area of the oil passages 6 1 a and 66 a communicating the first hydraulic pump 51 and the second hydraulic pump 52 and the hydraulic cylinder 106 for driving the stick is controlled by the PC throttle 8.
  • the oil supply passage opening area and PC opening area are adjusted.
  • the opening area of the oil passages 66 b and 69 communicating the stick drive hydraulic cylinder 106 and the reservoir tank 70 with the C_T throttle 9 (opening area of the hydraulic oil discharge passage, C-T Opening area) is adjusted.
  • the opening area of the oil passages 6 1 b and 66 c communicating the first hydraulic pump 51 and the second hydraulic pump 52 and the reservoir tank 70 by the bypass passage throttle 10 (opening area of the bypass passage) ) Is adjusted.
  • each of the control valves 57 to 60 each of the control valves 57 to 60,
  • Pilot pump 83 to control 6 2 to 65 and proportional pressure reducing valve 5 A pilot hydraulic circuit including 7a to 60a, 57b to 60b, 62a to 65a, and 62b to 65b is provided. In Fig. 2, the pilot pump 83 and the proportional pressure reducing valves 57a to 60a, 57b to 60b, 62a to 65a, 62b are provided in the pilot port hydraulic circuit. Only ⁇ 65b is shown, and the pilot oil pressure is indicated by the symbol P, omitting the pilot oil passage.
  • the proportional pressure reducing valves 57 a to 60 a, 57 b to 60 b, 62 a to 65 a, 62 b to 65 b are solenoid valves, and are operated by the controller 1 described later. It is activated by a signal.
  • the pilot oil pressure from the pilot pump 83 is applied to each of the control valves 57 to 60 and 62 to 65 as a predetermined pressure based on the operation signal from the controller 1.
  • the stick control valves 60 and 64 are driven to the required positions.
  • the supply and discharge of the hydraulic oil for the stick driving hydraulic cylinder 106 is adjusted, and these cylinders 105, 106 are driven to expand and contract to the required length, whereby the stick 104 is operated. .
  • the stick driving hydraulic cylinder 106 may be extended.
  • the pilot oil pressure is made to act on the second stick control valve 60 through the pilot oil passage.
  • the spool position of the second stick control valve 60 becomes the stick inner rotation position (stick position)
  • the hydraulic oil from the first hydraulic pump 51 of the first circuit portion 55 Is supplied to one chamber of the stick driving hydraulic cylinder 106 through the oil passages 61 and 67.
  • the hydraulic oil in the other chamber of the stick driving hydraulic cylinder 106 is discharged to the reservoir tank 70 via the oil passages 68 and 69.
  • the stick driving hydraulic cylinder 106 is extended, and the stick 104 is rotated inward as shown by the arrow d in FIG.
  • the stick driving hydraulic cylinder 106 may be contracted.
  • the pilot oil pressure is applied to the second stick control valve 60 through the pilot oil passage.
  • the spool position of the second stick control valve 60 becomes the stick outside rotation position (stick out position), and the hydraulic oil from the first hydraulic pump 51 of the first circuit portion 55 flows through the oil passage. It is supplied to the other chamber of the stick driving hydraulic cylinder 106 via 61 and 68.
  • the hydraulic oil in one chamber of the stick driving hydraulic cylinder 106 is discharged to the reservoir tank 70 through the oil passages 67 and 69.
  • the stick driving hydraulic cylinder 106 is contracted, and the stick 104 is rotated outward as shown by the arrow c in FIG.
  • each spool may be set to the neutral position (the hydraulic supply / discharge path shutoff position). As a result, the supply and discharge of the hydraulic oil in each oil chamber of the stick driving hydraulic cylinder 106 is stopped, and the stick 104 is held at the current position.
  • various sensors are attached to the construction machine configured as described above, and a detection signal from each sensor is sent to a controller 1 described later.
  • an engine 50 for driving the hydraulic pumps 51 and 52 is provided with an engine speed sensor 71.
  • the detection signal from the sensor 71 is sent to the controller 1 described later.
  • the controller 1 performs feedback control so that the actual engine speed becomes the target engine speed set by the engine speed setting dial during the operation.
  • a pressure sensor (PZS-P1) 72 and a pressure sensor (PZS-P2) 73 are provided to detect the pump discharge pressure. Detection signals from the sensors 72 and 73 are sent to a controller 1 described later.
  • pressure valves are provided downstream of the control valves 57 to 60 of the oil passage 61 of the first circuit unit 55 and the control valves 62 to 65 of the oil passage 66 of the second circuit unit 56, respectively.
  • the sensor (PZS-N1) 74 and the pressure sensor (PZS-N2) 75 are provided, and the detection signals from these pressure sensors 74 and 75 are sent to the controller 1 described later. It has become.
  • a pressure sensor (PZS-BMd) 80 is provided in an oil passage for supplying and discharging hydraulic oil to and from the boom drive hydraulic cylinder 105.
  • the boom drive hydraulic cylinder 100 is provided by the pressure sensor 80.
  • the rod side pressure (load pressure) of 5 can be detected.
  • the detection signal from the pressure sensor 80 is sent to a controller 1 described later.
  • a controller 1 is provided to control the construction machine configured as described above.
  • the controller 1 controls the first hydraulic pump 51, the second hydraulic pump 52, and the regeneration valve 76 based on the detection signals from the sensors 71 to 75 and 80 and the electric signal from the operation member 54. , 7 7, By outputting operation signals to the control valves 57 to 60, 62 to 65, the first hydraulic pump 51 and the second hydraulic The tilt angle control of the pump 52, the position control of the control valves 57 to 60 and 62 to 65, and the position control of the regeneration valves 76 and 77 are performed.
  • the tilt angle control of the first hydraulic pump 51 and the second hydraulic pump 52 by the controller 1 is performed on the downstream side of the bypass passage 61 b of the first circuit section 55 and the second circuit section 56.
  • Negative flow control is performed based on detection signals from the respective pressure sensors 74 and 75 provided downstream of the bypass passage 66c. Since the negative flow control is performed based on the pressures detected by the pressure sensors 74 and 75, the pressure detected by the pressure sensors 74 and 75 is also referred to as a negative control pressure.
  • the negative flow control is a pump flow control with a negative characteristic that reduces the pump discharge flow rate when the pressure downstream of the bypass passages 61b and 66c increases.
  • the negative flow control is based on the operation amount of the operation member 54, that is, the flow control in which the pump discharge flow rate is controlled according to the negative control pressure, and the load pressure applied to the actuator, that is, the pump discharge pressure. It is divided into horsepower control where the pump discharge flow rate is controlled.
  • the flow control can control the speed of the actuator (each cylinder) within the allowable horsepower.
  • the pump discharge flow rate can be controlled in accordance with the operation amount of the operation member 54, that is, the negative control pressure, whereby the speed of the actuator can be controlled.
  • the pump discharge flow rate (that is, the speed of the actuator) is determined by the following equation. Is done.
  • Pump discharge flow Q Allowable horsepower WZ Pump discharge pressure P
  • the pump discharge pressure P also changes, and the pump discharge flow rate Q also changes according to the above equation, so that the speed of the actuator changes as well. Will be.
  • the pump discharge flow rate Q is not controlled according to the operation amount of the operation member 54, but is controlled according to the load pressure applied to the actuator, that is, the pump discharge pressure P.
  • the control in a state where the magnitude of the flow rate Q depends on the allowable horsepower W of the engine 50 that drives the first hydraulic pump 51 and the second hydraulic pump 52 is called horsepower control.
  • the operation member 54 when the operation member 54 is in the neutral position, that is, when the operator does not operate the operation member 54, the work machine 118 does not work at all, and each actuator (cylinder, etc.) is operated. Since there is no need to drive the pump, the pump discharge flow rate from the hydraulic pumps 51 and 52 is desirably set to zero.
  • each of the control valves 57 to 60 and 62 to 65 is arranged so that the bypass passages 6 lb and 66 c are open at the spool neutral position. That is, when the operating member 54 is in the neutral position, the hydraulic oil supplied from the hydraulic pumps 51 and 52 returns to the reservoir tank 70 through the bypass passages 61b and 66c. I have. As a result, when the operation member 54 is in the neutral position, the pressure immediately upstream of the throttles 81, 82 provided downstream of the bypass passages 61b, 66c increases, and the negative flow control is performed. Thus, the pump discharge flow rate from the variable displacement hydraulic pumps 51 and 52 is controlled to decrease.
  • the throttle (orifice) 8 1 is located downstream of the bypass passages 6 lb and 66 c for returning the hydraulic oil not supplied to the hydraulic actuator through the respective control valves to the reservoir tank 70.
  • 82 are provided.
  • Pressure sensors 74 and 75 are interposed in the bypass passages 6 1 b and 66 c immediately upstream of the throttles 8 1 and 82, and the throttles detected by the pressure sensors 74 and 75 are provided.
  • the tilt angles of the hydraulic pumps 51 and 52 are controlled based on the pressures immediately upstream of the pumps 81 and 82.
  • the control valves 57 to 60 and 62 to 65 move according to the operation amount of the operation member 54, and the bypass passages 61b and 66c are moved. And the flow rate of hydraulic oil flowing through the bypass passages 6 1 b and 66 c decreases, but the diameter of the throttles 8 1 and 8 2 is constant, so the throttles 8 1 and 8 are reduced by the reduced flow rate.
  • the pressure immediately upstream of 2 that is, the pressure detected by the pressure sensors 74 and 75 decreases, and the variable displacement hydraulic pumps 51 and 52 increase the pump discharge flow rate in accordance with the reduced pressure.
  • the tilt angle control is performed.
  • the pump discharge flow rate is controlled to increase according to the operator's request, that is, the operation amount of the operation member 54 by the operator, This means that by operating the operating member 54, the operator can control the pump discharge flow rate from the hydraulic pumps 51 and 52 to control the speed of each actuator (each cylinder and the like).
  • the control valves 57 to 60 and 62 to 65 by the controller 1, the control valves 57 to 60 and 60 according to the operation of the operation member 54 by the operator are used. In addition to the position control of 62 to 65, the position control of each control valve 57 to 60 and 62 to 65 according to the engine speed is also performed.
  • the controller 1 is a proportional pressure reducing valve (a pilot pressure) that adjusts the pilot oil pressure applied to each of the control valves 57 to 60 and 62 to 65 based on the electric signal from the operation member 54.
  • Control valve) 57a to 60a, 57b to 60b, 62a to 65a, 62b to 65b I have.
  • controller 1 controls each of the control valves 57 to 7 based on a detection signal from an engine speed sensor 71 attached to an engine 50 that drives the first hydraulic pump 51 and the second hydraulic pump 52.
  • Proportional pressure reducing valve for adjusting pilot oil pressure acting on 60, 62 to 65 57 a to 60 a, 57 b to 60 b, 62 a to 65
  • An operation signal is output to control the operation of a, 62b to 65b.
  • 57 b to 60 b, 62 a to 65 a, 62 b to 65 b are operated, and by this, the pressure of the pilot hydraulic pressure supplied from the pilot pump 83 is adjusted, and The spool stroke amount (spool movement amount) of the control valves 57 to 60 and 62 to 65 is adjusted.
  • the control device for a construction machine is configured as described above, and various controls are performed by the controller 1. In order to lower the weight of the stick in the direction in which gravity acts, the self-weight lowering control of the stick 104 is performed.
  • FIG. 1 is a control block diagram for explaining the self-weight drop control of the stick by the control device of the construction machine according to the present embodiment.
  • the controller 1 includes a proportional pressure reducing valve control means 2 and a pump tilt angle control means 3 in order to perform the self-weight drop control of the stick 104. Have been.
  • the proportional pressure reducing valve control means 2 includes a basic control amount setting means 4 and a correction means 5 among them.
  • the basic control amount setting means 4 calculates a basic control amount of the proportional pressure reducing valves 60a, 60b, 64a, 64b based on an electric signal corresponding to the operation amount from the operation member 54. This basic control amount is output to the correction means 5.
  • the basic control amount relates the operation amount of the operating member 54 as shown in FIG. 4 to the basic control signals of the proportional pressure reducing valves 60a, 60b, 64a, and 64b. Required by map.
  • the operation amount of the operation member 54 is set so that the larger the operation amount of the operation member 54, the larger the movement amount of the proportional pressure reducing valves 60a, 60b, 64a, and 64b.
  • the basic control signal is set to increase as the number increases. Note that in FIG. 4, the basic control signal is constant above the predetermined operation amount because the movement of the proportional pressure reducing valves 60a, 60b, 64a, and 64b at the predetermined operation amount is the maximum.
  • the correction means 5 calculates the control signal rates (correction coefficients) of the proportional pressure reducing valves 60 a, 60 b, 64 a, and 64 b based on the detection signal from the engine speed sensor 71.
  • the signal rate is calculated based on the basic control amount By multiplying this control amount, the basic control amount of the proportional pressure reducing valves 60a, 60b, 64a, and 64b is corrected to calculate a correction control amount. a, 60, 64a, 64b.
  • control signal rate is obtained from a map as shown in FIG. 5, which associates the engine speed with the control signal rate of the proportional pressure reducing valve.
  • the control signal rate is calculated so that the control signal rate of the proportional pressure reducing valves 60a, 60b, 64a, 64b decreases as the engine speed detected by the engine speed sensor 71 decreases. It is set as shown by NZNmax.
  • the control signal rate is set so that the stroke amount of the spool constituting the first stick control valve 60 and the second stick control valve 64 decreases as the engine rotation speed decreases.
  • the control signal rates of the proportional pressure reducing valves 60a, 60b, 64a, 64b become Nmin / Nmax.
  • the correction means 5 outputs a control signal corresponding to the correction control amount to the proportional pressure reducing valves 60a, 60b, 64a, 64b.
  • the proportional pressure reducing valves 60a, 60b, 64a, 64b are operated in accordance with the control amount calculated by the proportional pressure reducing valve control means 2, and the pilot oil pressure from the pilot pump 83 is proportionally reduced.
  • the pressure is reduced to a predetermined pressure by the valves 60 a, 60 b, 64 a, 64 b and acts on the first stick control valve 60 and the second stick control valve 64, and the first stick control valve 60
  • the spool constituting the second stick control valve 64 moves.
  • FIG. 6 is a map in which the correction control signal is related to the stroke amounts of the first stick control valve 60 and the second stick control valve 64.
  • the spools constituting the first stick control valve 60 and the second stick control valve 64 increase as the correction control signal (basic control signal X control signal rate) increases. It is controlled so as to be the stroke amount.
  • the opening area of the oil passage (PC opening area) that connects the first hydraulic pump 51 or the second hydraulic pump 52 to the stick driving hydraulic cylinder 106, the stick driving hydraulic cylinder 10 6
  • the opening area of the oil passage that connects the reservoir and the reservoir 70 (C—T opening area), the oil passage that connects the first hydraulic pump 51 or the second hydraulic pump 52 to the reservoir 70
  • the opening area changes accordingly.
  • the negative control pressure changes according to the bypass passage opening area which is adjusted according to the operation amount of the operation member 54, and the hydraulic pumps 51 and 52 change according to the changed negative control pressure.
  • the tilt angle control of 52 is performed, and the pump flow rate is controlled.
  • the control characteristics of the C-T opening area when the operating member 54 is fully operated may differ depending on the engine rotation speed.
  • the CT opening area is controlled in accordance with the operation amount of the operation member 54.
  • the control characteristics of the CT opening area at the maximum engine speed are indicated by solid line A
  • the control characteristics of the CT opening area at the minimum engine speed are indicated by solid line B. Is shown.
  • a broken line C indicates a conventional control characteristic of the CT opening area.
  • the setting of the engine speed is not limited to the maximum and minimum, but can be set arbitrarily. If possible, the control characteristics of the C-T opening area when the operation member 54 is fully operated may be set according to the engine speed.
  • the C-T opening area is controlled in proportion to the operation amount of the operation member 54 and the engine rotation speed, but when the operation amount of the operation member 54 is the maximum ( In the case of full operation), the C-T opening area when the engine speed is the minimum is larger than the C-T opening area when the engine speed is the maximum, regardless of the operation of the operating members 54 by the operator.
  • the spool stroke amount (spool movement amount) constituting the first stick control valve 60 and the second stick control valve 64 is controlled so as to be small.
  • the control characteristic indicated by the solid line A in FIG. The amount of spool stroke constituting the control valve 60 for the first stick and the control valve 64 for the second stick is set so that the area is maximized. Pressure is not generated to improve work efficiency.
  • the operating member 54 is fully operated by the operator to make the spool the maximum stroke S max, and the maximum pump flow rate as the maximum PC opening area is set to the hydraulic cylinder for stick drive.
  • the stick 104 is to be lowered by its own weight while maintaining the maximum descent speed of the stick drive hydraulic cylinder 106, the spool stroke is reduced and the spool position is adjusted. Is controlled so as to return from the most moved position to the neutral position side in accordance with the operation amount of the operation member 54 during the operation.
  • control is performed such that the spool stroke amount is reduced and the spool position is returned to the neutral position side when the engine rotation speed is the maximum.
  • the return amount of the spool to the neutral position is set to zero, the spool position is not controlled to return the spool position to the neutral position, and the spool stroke amount is It may be kept controlled according to the operation amount.
  • the hydraulic oil supply side pressure in the stake driving hydraulic cylinder 106 should be a positive pressure (pressure in the direction of its own weight descent) and a predetermined pressure (for example, it is necessary to ensure the order of about 5 kgf / cm 2).
  • the spool stroke amount is set so that the CT opening area is maximized when the engine speed is the maximum, when the engine speed is the minimum (when the pump flow rate is Set the spool stroke amount so that the C-T opening area is maximized at the minimum, and the cavitation is applied to the hydraulic oil supply side to each cylinder (that is, the oil passage between the pump and each cylinder).
  • the diameter of the C-T throttle 9 is set so that the cylinder descends at a speed that does not cause the occurrence of excessive throttling, when the engine speed is high (when the pump flow rate increases) due to the C-T throttle 9, This is because work efficiency is reduced.
  • the CT opening area is maximized by the control characteristic indicated by the solid line B in FIG.
  • the spools constituting the first stick control valve 60 and the second stick control valve 64 are controlled so as to return to the neutral direction.
  • the CT opening area is reduced compared to when the engine speed is high.
  • C _ Controller 1 has a data sheet (map) relating spool stroke amount S corresponding to T opening area A. The details will be described later.
  • the CT opening area is adjusted by changing the stroke amount of the spool constituting the first stick control valve 60 and the second stick control valve 64.
  • C—T opening area is
  • the engine rotational speed is adjusted to a predetermined rotational speed (approximately 1 0 0 0 rpm) in back pressure Jo Tokoro pressure (approximately 4 0 kgf Z cm 2 or so).
  • the PC opening area becomes the maximum, but also in this case, the pressure loss should be prevented.
  • the diameter of the P_C aperture 8 for adjusting the P_C opening area is set to be sufficiently large.
  • the first stick control is performed as described above.
  • the spool constituting the valve 60 and the second stick control valve 64 is controlled so as to return to the neutral direction in accordance with the engine speed, and even if the PC opening area is reduced, the PC throttle is provided. 8 does not cause pressure loss, etc., and does not affect the performance of construction machinery.
  • bypass passage opening area is the largest when the engine speed is the maximum (pump flow rate is the largest) and the operating member 54 is not operated, and the bypass passage opening area is the largest.
  • the diameter of the bypass passage restrictor 10 for adjusting the bypass passage opening area is set so as not to cause the occurrence.
  • the first stick control valve 60 and the second stick control valve 6 are used to reduce the C-T opening area. 4 is controlled to return to the neutral direction, the opening area of the bypass passage increases, the negative control pressure increases, and the pump flow rate decreases. Will have an effect.
  • the tilt angle control amount correcting means 7 tilts the maximum tilt angle control amount instead of the basic tilt angle control amount in the negative flow control. Set as angle control amount It is like that.
  • the spool stroke amount is maximized, the spool is moved most, and the C—T opening area reduced by the C—T aperture 9 is the force that maximizes the aperture.
  • the spool at the position where the spool stroke amount is maximized by the full operation of the operation member 54 by the operator and is the most moved is set so that the C-T opening area becomes small. Control is performed so that the spool is returned to the neutral position more (the return amount of the spool is large)
  • the spool at the most moved position is neutral so that the C-T opening area is large. It is controlled to return slightly to the position side (spool return amount is small or zero).
  • the opening area of the oil passage between the stick driving hydraulic cylinder 106 and the reservoir tank 70 according to the engine rotation speed is determined.
  • C_T opening area That is, in the present embodiment, the first stick control valve 60 and the second stick control valve 64 are configured such that the C_T opening area increases as the engine rotation speed increases. The amount of stroke of the spool is controlled. C By this, for example, control is performed so that the engine speed is at a predetermined rotation speed (about 100 rpm) and the back pressure is at a predetermined pressure (about 40 kgf Z cm 2 ).
  • the predetermined pressure approximately 40 kgf / cm 2
  • the predetermined pressure approximately 40 kgf / cm 2
  • the control characteristic of the C-T opening area when the operation amount of the operation member 54 is the maximum is set according to the engine speed.
  • the present invention is not limited to this. As shown in FIG. 9, not only when the operation amount of the operation member 54 is the maximum, but also when the control characteristic of the C-T opening area according to the operation amount of the operation member 54 is set for each engine speed. good.
  • the case where the engine speed is maximum and the case where the engine speed is minimum are shown.
  • the case where the engine speed is maximum is indicated by a solid line A
  • the case where the engine speed is minimum is indicated by a solid line B.
  • the P_C opening area, the C-T opening area, and the bypass passage opening area are all provided in the first stick control valve 64 and the second stick control valve 60 configured as one spool valve. Because it is determined by the P-C throttle 8, the C-T throttle 9, and the bypass passage throttle 10, the first stick is used to adjust the C-T opening area when controlling the self-weight drop of the stick 104.
  • the control valve 64 or the second stick control valve 60 is moved, the bypass passage opening area is also adjusted, and the bypass flow rate of the hydraulic oil flowing through the bypass passages 6 1 b and 66 c also changes. To be lost Therefore, the pressure of the hydraulic oil downstream of the bypass passage used in the negative flow control will change.
  • the pump tilt angle control means As will be described later, the pump tilt angle control means
  • the pump tilt angle control amount is corrected by the tilt angle control amount correction means 7 of 3.
  • the pump tilt angle control means 3 includes basic tilt angle control amount setting means 6 and tilt angle control amount correction means 7.
  • the basic tilt angle control amount setting means 6 and the tilt angle control amount correction means 7 perform pump tilt angle control as shown in the flowcharts of FIGS. 12 and 13 described later.
  • the basic tilt angle control amount setting means 6 determines the basic tilt angle control amount of the first hydraulic pump 51 and the second hydraulic pump 52 based on the detection signals from the pressure sensors 74 and 75.
  • the basic tilt angle control amount is output to the tilt angle control amount correction means 7.
  • the basic tilt angle control amount is a negative valve control that controls the discharge flow rate from the hydraulic pump based on a characteristic that is substantially inversely proportional to the flow rate of the hydraulic oil in the bypass passages 6 lb and 66 c. It is set, specifically, as follows.
  • the basic tilt angle control amount setting means 6 sets the bypass passages 6 1 b and 66 c of the first circuit portion 55 and the second circuit portion 56 detected by the pressure sensors 74 and 75.
  • the operating hydraulic pressure (negative control pressure) P N1 , P N2 on the downstream side is read, and the negative control pressure P N1 is read from the map as shown in Fig. 10 in which the negative control pressure P N and the required flow rate Q N are related. It is adapted to set the required flow rate Q N1, Q N2 corresponding to P N2 (specifically required flow rate Q N1, the pump tilting angle corresponding to Q N2 V N1, V N2) .
  • the required flow rate is the flow rate required in negative flow control. Also, in Figure 10 (Specifically required flow pump tilting angle V N1 to equivalent to Q N1) required flow rate Q N1 corresponding to the negative control pressure P N1 are shown only.
  • the basic tilt angle control amount setting means 6 calculates the pump discharge pressures P P1 and P P2 of the first hydraulic pump 51 and the second hydraulic pump 52 detected by the pressure sensors 72 and 73. Loading, from the map shown in the pump discharge pressure P P and allowable flow Q 1 1 and P digits relationship Dzu, corresponding to the pump discharge pressure read P P1, P P2 allowable flow Q P1, Q P2 ( Specifically, the pump tilt angles V P1 and V P2 ) corresponding to the allowable flow rates Q P1 and Q P2 are set.
  • the allowable flow rate refers to a pump discharge flow rate according to the allowable horsepower of the engine 50 that drives the first hydraulic pump 51 and the second hydraulic pump 52. Further, in FIG. 1 1 shows only allowable flow Q P1 corresponding to the pump discharge pressure P P1 (pump tilting angle V P1 specifically corresponding to allowable flow Q P1).
  • the basic tilt angle control amount setting means 6 compares the required flow rate Q N1, Q N2 above the allowable flow Q P1, Q P2, the smaller the pump flow rate (requested flow Q N1, Q N2 or acceptable
  • the pump tilt angles (pump tilt angles V N1 , V N2 or pump tilt angles VP 1 , V P2 ) are set so that the flow rates Q P1 and Q P2 ), and this is used as the first tilt angle control signal.
  • Output is provided to the hydraulic pump 51 and the second hydraulic pump 52.
  • the basic tilt angle control amount setting means 6 is configured as described above, and operates as shown in the flowchart of FIG.
  • step S10 the negative control pressures P N1 and P N2 are read, and in step S20, the pump discharge pressures P P1 and P P2 are read.
  • step S in step 4 0 Calculate the permissible flow rates Q P1 and Q P2 corresponding to the pump discharge pressures P P1 and P P2 read in 20 from the map in Fig. 11. You.
  • step S 5 allowed the required flow rate Q N1, Q N2 in Step S 5 0 flow rate Q P1, Q less whether determined than P2, the result of this determination, required flow rate Q N1, Q N2 is allowable flow Q P1, If it is determined that the flow rate is smaller than Q P2 , the process proceeds to step S60, where the required flow rates Q N1 and Q N2 are set as the pump flow rates, and the routine returns.
  • the tilt angles of the first hydraulic pump 51 and the second hydraulic pump 52 are set to be the tilt angles corresponding to the required flow rates Q N1 and Q N2 .
  • step S70 the allowable flow rates Q P1 and Q P2 are set as the pump flow rates and the return is performed. I do.
  • the tilt angles of the first hydraulic pump 51 and the second hydraulic pump 52 are set to be the tilt angles according to the allowable flow rates Q P1 and Q P2 .
  • the tilt angle control amount correction means 7 sets the basic tilt angle control amount set by the basic tilt angle control amount setting means 6. Instead of the signal, the first hydraulic pump 5 is used as a corrected tilt angle control signal with a maximum tilt angle control signal that maximizes the pump tilt angle of both the first hydraulic pump 51 and the second hydraulic pump 52. 1, and output to the second hydraulic pump 52.
  • the operation amount signal from the operation member 54 and the detection signal from the engine speed sensor 71 are input to the tilt angle control amount correction means 7, and the operation member 54 is fully operated based on these signals. It is determined whether the operating member 54 is fully operated and the engine speed is not the maximum. If the result of this determination is that the operation member 54 is fully operated and the engine speed is not the maximum, the first A maximum tilt angle control signal that maximizes the tilt angle of the hydraulic pumps 51 and 52 is output to the first hydraulic pump 51 and the second hydraulic pump 52 as a tilt angle control signal. It has become.
  • the tilt angle control amount correcting means 7 is configured as described above, and operates as shown in the flowchart of FIG.
  • step A10 the operation amount signal from the operation member 54 is read, and in step A20, the detection signal from the engine speed sensor 71 is read. Then, in step A30, it is determined whether or not the operating member 54 is fully operated. If the result of this determination is that the operating member 54 is fully operated, the flow proceeds to step A40.
  • the basic tilt angle control signal set by the basic tilt angle control amount setting means 6 is used as the tilt angle control signal for the first hydraulic pumps 51 and 2. Return to output to hydraulic pump 52.
  • step A40 it is determined whether or not the engine rotation speed is the maximum. If it is determined that the engine rotation speed is the maximum, the correction by the tilt angle control amount correction means 7 is not performed.
  • step 60 the basic tilt angle control signal set by the basic tilt angle control amount setting means 6 is output to the first hydraulic pump 51 and the second hydraulic pump 52 as a tilt angle control signal. .
  • the process proceeds to step A50, and the first hydraulic pump 5 is used instead of the basic tilt angle control signal set by the basic tilt angle control amount setting means 6. 1, Set the maximum tilt angle control signal that maximizes the tilt angle of the second hydraulic pump 5 2 as the tilt angle control signal, and in step A 60, set the tilt angle control signal to the first hydraulic pump 5. 1, Output to the second hydraulic pump 52.
  • the pump displacement angle control means 3 controls the displacement of the first hydraulic pump 51 and the second hydraulic pump 52 based on the detection signals from the pressure sensors 72, 73, 74, 75.
  • a control signal corresponding to the angle control amount is calculated, and this control signal is used as an operation amount signal from the operating member 54 and an engine speed sensor 71 Correction is performed based on the detection signal to calculate a corrected tilt angle control amount. Then, a control signal corresponding to the corrected tilt angle control amount is output to the first hydraulic pump 51 and the second hydraulic pump 52.
  • the tilt angles of the first hydraulic pump 51 and the second hydraulic pump 52 are controlled to the control amount calculated by the pump tilt angle control means 3, and set to a predetermined pump displacement.
  • the pump flow rates from the first hydraulic pump 51 and the second hydraulic pump 52 are adjusted.
  • the self-weight drop control of the stick 104 has been described.
  • the present invention is not limited to this.
  • the same weight drop control can be performed for the bucket and the bucket 108 as well.
  • the diameter of the C_T throttle 9 is set to be larger than that of the conventional one so as to be able to cope with the case where the engine speed is maximum.
  • the stroke amount of the spools constituting the control valves 60 and 64 can be changed according to the engine speed.
  • the C—T opening area is adjusted.
  • the method of adjusting the C ⁇ opening area is not limited to this.
  • the control valve 6 instead of changing the diameter of the C ⁇ throttle 9, the control valve 6 may be used.
  • the position of the C-throttle 9 formed on the spools constituting the control valves 60 and 64 may be changed. Only one stroke may be changed.
  • a spool is provided separately from the control valves 60 and 64 in the oil passage between the stick driving hydraulic cylinder 106 and the reservoir tank 70 and downstream of the position where the control valves 60 and 64 are disposed.
  • a control valve configured as a valve is provided, and as the engine speed increases, the opening area of the oil passage between the stick driving hydraulic cylinder 106 and the reservoir tank 70 (C ⁇ opening area) increases.
  • the stroke amount of the spool constituting the control valve may be controlled so as to be smaller.
  • the opening area of the bypass passage is adjusted during the self-weight drop control of the stick 104, and the bypass flow rate of the hydraulic oil flowing through the bypass passages 6 1b and 66 c may change. Therefore, it is possible to prevent the pressure of the hydraulic oil downstream of the bypass passage used in the negative flow control from being changed.
  • the spool is moved by the pilot pressure.
  • the present invention is not limited to this, and the spool may be moved by an electromagnet or the like.
  • a control device and a control method for a construction machine according to the present invention include a construction machine having a stick or the like and performing an operation of lowering the work machine by its own weight.

Abstract

L'invention concerne un appareil de commande d'un engin de construction, destiné à améliorer l'efficacité du travail lorsqu'un actionneur hydraulique est en chute libre, de manière à décroître la perte d'énergie, à améliorer l'économie de carburant, diminuer la perte thermique, et améliorer les performances de refroidissement. Cet appareil comprend des pompes hydrauliques (51, 52) entraînées par un moteur, afin de prélever le fluide hydraulique à partir d'un réservoir, un actionneur hydraulique entraîné par le fluide hydraulique déchargé par les pompes hydrauliques, une canalisation à travers laquelle le fluide hydraulique est acheminé, de l'actionneur hydraulique vers le réservoir, une soupape de commande (60, 64) montée dans la canalisation, afin de réguler le débit du fluide hydraulique circulant dans la canalisation, un capteur de vitesse (71) de moteur, destiné à détecter la vitesse de rotation du moteur, ainsi que des moyens de commande (1) de la soupape de commande, aux fins de réglage de l'ouverture de la canalisation en fonction de l'entrée à partir d'un manipulateur (54). Les moyens de commande de la soupape de commande agissent en fonction de la vitesse du moteur détectée par le capteur de vitesse.
PCT/JP2000/002441 1999-04-26 2000-04-14 Procede et dispositif de commande d'un engin de construction WO2000065239A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP11/118234 1999-04-26
JP11823499A JP3629382B2 (ja) 1999-04-26 1999-04-26 建設機械の制御装置

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Publication Number Publication Date
WO2000065239A1 true WO2000065239A1 (fr) 2000-11-02

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PCT/JP2000/002441 WO2000065239A1 (fr) 1999-04-26 2000-04-14 Procede et dispositif de commande d'un engin de construction

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP3165777A4 (fr) * 2014-07-03 2018-04-04 Nabtesco Corporation Circuit hydraulique pour machine de construction

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6877417B2 (en) 2001-04-17 2005-04-12 Shin Caterpillar Mitsubishi Ltd. Fluid pressure circuit
JP5450147B2 (ja) * 2010-02-16 2014-03-26 カヤバ工業株式会社 建設機械のロードセンシング制御装置
JP6936690B2 (ja) * 2017-10-18 2021-09-22 川崎重工業株式会社 油圧ショベル駆動システム
WO2023074809A1 (fr) * 2021-10-29 2023-05-04 住友建機株式会社 Pelle excavatrice

Citations (3)

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Publication number Priority date Publication date Assignee Title
JPS5837302A (ja) * 1981-08-31 1983-03-04 Mitsubishi Heavy Ind Ltd 作業機のポンプ制御装置
JPH02142902A (ja) * 1988-11-25 1990-06-01 Hitachi Constr Mach Co Ltd 油圧駆動装置
JPH0419406A (ja) * 1990-04-05 1992-01-23 Toshiba Mach Co Ltd 油圧作業回路

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5837302A (ja) * 1981-08-31 1983-03-04 Mitsubishi Heavy Ind Ltd 作業機のポンプ制御装置
JPH02142902A (ja) * 1988-11-25 1990-06-01 Hitachi Constr Mach Co Ltd 油圧駆動装置
JPH0419406A (ja) * 1990-04-05 1992-01-23 Toshiba Mach Co Ltd 油圧作業回路

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP3165777A4 (fr) * 2014-07-03 2018-04-04 Nabtesco Corporation Circuit hydraulique pour machine de construction
US10161109B2 (en) 2014-07-03 2018-12-25 Nabtesco Corporation Hydraulic circuit for construction machine

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JP3629382B2 (ja) 2005-03-16
JP2000309952A (ja) 2000-11-07

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