EP1416096B1 - Hydraulic excavator with a hydraulic circuit - Google Patents

Hydraulic excavator with a hydraulic circuit Download PDF

Info

Publication number
EP1416096B1
EP1416096B1 EP03256761A EP03256761A EP1416096B1 EP 1416096 B1 EP1416096 B1 EP 1416096B1 EP 03256761 A EP03256761 A EP 03256761A EP 03256761 A EP03256761 A EP 03256761A EP 1416096 B1 EP1416096 B1 EP 1416096B1
Authority
EP
European Patent Office
Prior art keywords
pressure
bucket
pilot
boom
boom raising
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
EP03256761A
Other languages
German (de)
English (en)
French (fr)
Other versions
EP1416096A1 (en
Inventor
Hidekazu c/o Kobelco Constr. Mach. Co. Ltd Oka
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Kobelco Construction Machinery Co Ltd
Original Assignee
Kobelco Construction Machinery Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Kobelco Construction Machinery Co Ltd filed Critical Kobelco Construction Machinery Co Ltd
Publication of EP1416096A1 publication Critical patent/EP1416096A1/en
Application granted granted Critical
Publication of EP1416096B1 publication Critical patent/EP1416096B1/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B11/00—Servomotor systems without provision for follow-up action; Circuits therefor
    • F15B11/16—Servomotor systems without provision for follow-up action; Circuits therefor with two or more servomotors
    • F15B11/161—Servomotor systems without provision for follow-up action; Circuits therefor with two or more servomotors with sensing of servomotor demand or load
    • F15B11/166—Controlling a pilot pressure in response to the load, i.e. supply to at least one user is regulated by adjusting either the system pilot pressure or one or more of the individual pilot command pressures
    • 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
    • E02F9/2232—Control of flow rate; Load sensing arrangements using one or more variable displacement pumps
    • E02F9/2235—Control of flow rate; Load sensing arrangements using one or more variable displacement pumps 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
    • E02F9/2285—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
    • F15B11/161—Servomotor systems without provision for follow-up action; Circuits therefor with two or more servomotors with sensing of servomotor demand or load
    • F15B11/162—Servomotor systems without provision for follow-up action; Circuits therefor with two or more servomotors with sensing of servomotor demand or load for giving priority to particular servomotors or users
    • 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
    • F15B11/167—Servomotor systems without provision for follow-up action; Circuits therefor with two or more servomotors with sensing of servomotor demand or load using pilot pressure to sense the 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
    • F15B2211/2053—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
    • F15B2211/30—Directional control
    • F15B2211/305—Directional control characterised by the type of valves
    • F15B2211/3056—Assemblies of multiple valves
    • F15B2211/30565—Assemblies of multiple valves having multiple valves for a single output member, e.g. for creating higher valve function by use of multiple valves like two 2/2-valves replacing a 5/3-valve
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/30—Directional control
    • F15B2211/305—Directional control characterised by the type of valves
    • F15B2211/3056—Assemblies of multiple valves
    • F15B2211/3059—Assemblies of multiple valves having multiple valves for multiple output members
    • F15B2211/30595—Assemblies of multiple valves having multiple valves for multiple output members with additional valves between the groups of valves for multiple output members
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/30—Directional control
    • F15B2211/31—Directional control characterised by the positions of the valve element
    • F15B2211/3105—Neutral or centre positions
    • F15B2211/3116—Neutral or centre positions the pump port being open in the centre position, e.g. so-called open centre
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/30—Directional control
    • F15B2211/32—Directional control characterised by the type of actuation
    • F15B2211/329—Directional control characterised by the type of actuation actuated by fluid 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
    • F15B2211/50—Pressure control
    • F15B2211/575—Pilot 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
    • F15B2211/63—Electronic controllers
    • F15B2211/6303—Electronic controllers using input signals
    • F15B2211/6306—Electronic controllers using input signals representing a pressure
    • F15B2211/6316—Electronic controllers using input signals representing a pressure the pressure being a pilot pressure
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/60—Circuit components or control therefor
    • F15B2211/635—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
    • F15B2211/70—Output members, e.g. hydraulic motors or cylinders or control therefor
    • F15B2211/71—Multiple output members, e.g. multiple hydraulic motors or cylinders
    • 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
    • F15B2211/76—Control of force or torque of the output member
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/70—Output members, e.g. hydraulic motors or cylinders or control therefor
    • F15B2211/78—Control of multiple output members

Definitions

  • This invention relates to a hydraulic circuit of a hydraulic excavator.
  • Japanese Patent Application Publication No. Hei 8-13547 discloses that a pump pressure is increased to more than a load pressure of the boom cylinder by throttling a flow rate for supply to the bucket cylinder on composite operations including the above three operations.
  • a hydraulic excavator of the present invention comprises a boom, an arm, a bucket and a hydraulic circuit.
  • the hydraulic circuit comprises a boom cylinder for actuating the boom of a hydraulic excavator; an arm cylinder for actuating the arm of the excavator, a bucket cylinder for actuating the bucket of the excavator, a first hydraulic pump, and a second hydraulic pump, and is constructed such that pressure oil provided from the first hydraulic pump is fed in parallel to both boom cylinder and bucket cylinder through a boom control valve and a bucket control valve, while pressure oil provided from the second hydraulic pump is fed in parallel to both boom cylinder and arm cylinder through a boom control valve for confluence and a control valve for the arm, wherein each of the control valves is a hydraulic pilot switching valve adapted to operate in accordance with the amount of operation of an operating means, the hydraulic circuit further comprising a pilot pressure control means which, in accordance with the amount of an arm pulling operation and that of a boom raising operation, reduces a pilot pressure fed
  • the pilot pressure fed to the bucket control valve is reduced to diminish the stroke of the same valve, whereby a throttling effect of the control valve itself is exerted to increase the pump pressure and there is ensured a boom raising operation.
  • the boom raising operation is ensured not by throttling an inlet-side passage (main passage) in the bucket control valve, but by reducing the pilot pressure fed to the same valve. Therefore, even if the pump flow rate decreases due to a decrease of engine speed, there is no fear of occurrence of cavitation because the tank flow rate is also throttled at the same time.
  • the pilot pressure control means is constructed such that a tank line communicating with a tank is connected a bucket digging-side pilot line, and a bucket digging-side switching valve whose degree of opening changes in accordance with a boom raising pilot pressure, as well as a first throttle means, are provided in the tank line, further, a second throttle means is provided in the pilot line upstream of the tank line.
  • a boom raising switching valve whose degree of opening changes in accordance with an arm pulling pilot pressure is connected to a boom raising pilot line, and a boom raising pilot pressure as an output of the boom raising switching valve is fed to a pilot port of the bucket digging-side switching valve.
  • variable throttle means whose degree of opening can be adjusted.
  • the pilot pressure control means may comprise an electromagnetic proportional pressure reducing valve disposed in the bucket digging-side pilot line of the bucket control valve, an arm pulling detector means for detecting the amount of the arm pulling operation, a boom raising detector means for detecting the amount of the boom raising operation, and a controller which issues to the electromagnetic proportional pressure reducing valve a command of a secondary pressure proportional to the amount of the arm pulling operation and that of the boom raising operation detected by both detector means.
  • the pilot pressure control means may comprise a boom raising pressure detector means for detecting a boom raising-side pressure of the boom cylinder and a pump pressure detector means for detecting an operating pressure of the first hydraulic pump, wherein the command of the secondary pressure to the electromagnetic proportional pressure reducing valve may be issued on condition that the operating pressure of the first hydraulic pump is higher than the boom raising-side pressure.
  • Working attachments in a hydraulic excavator are composed of a boom, an arm, a bucket, and hydraulic cylinders (boom cylinder, arm cylinder, bucket cylinder) for actuating those components.
  • Various works including excavating and loading works, are carried out by various operations, including boom raising/boom lowering, arm pushing/arm pulling, and bucket digging or bucket-in/bucket dump or bucket-out operations.
  • both a boom cylinder which requires a large flow rate and a bucket cylinder for which a small flow rate will do are actuated usually by a common hydraulic pump.
  • a boom cylinder and a bucket cylinder are actuated by a first hydraulic pump, while an arm cylinder is actuated by a second hydraulic pump, and in this state a portion of pressure oil fed from the second hydraulic pump is allowed to join the pressure oil in the boom cylinder to ensure a required boom operation speed.
  • the numeral 1 denotes a first hydraulic pump.
  • a bucket cylinder 2 and a boom cylinder 3 are connected to the first hydraulic pump 1 in parallel through a bucket control valve 4 and a boom control valve 5, respectively.
  • Numeral 6 denotes a second hydraulic pump.
  • the boom cylinder 3 and an arm cylinder 7 are connected to the second hydraulic pump 6 in parallel through a boom control valve 8 for confluence and an arm control valve 9, respectively.
  • the mark T denotes a tank.
  • the control valves 4, 5, 8, and 9 are constructed as hydraulic pilot valves (hydraulic pilot switching valves) adapted to operate switchingly in accordance with pilot pressures provided from remote control valves 10, 11, and 12 for bucket, boom, and arm, respectively, which serve as operating means.
  • the bucket control valve 4 and the boom control valve 5 are set to respective left-hand positions (bucket digging position and boom raising position) in the figure, while the boom control valve 8 for confluence and the arm control valve 9 are set to respective righthand positions (confluent position, arm pulling position) in the figure.
  • pressure oil is fed from the first hydraulic pump 1 to both bucket and boom cylinders 2, 3 and from the second hydraulic pump 6 to both boom and arm cylinders 3, 7 at flow rates proportional to control valve operation quantities, whereby the cylinders 2, 3, and 7 extend.
  • Fig. 1 as pilot lines for the supply of a pilot pressure to each of the control valves 4, 5, 8, and 9, there are shown only a bucket digging-side pilot line 13, a boom raising-side pilot line 14, a confluent pilot line 15 connected in parallel with the pilot line 14, and an arm pulling-side pilot line 16.
  • bucket dump-side, boom lowering-side, confluence stop-side, and arm pushing-side pilot lines are not shown.
  • a tank line 17 is connected to the pilot digging-side pilot line 13.
  • a bucket digging-side switching valve 18 as a hydraulic pilot valve whose degree of opening changes in accordance with a pilot pressure, and a first throttle 19 (throttle valve), are provided in the tank line 17. Further, a second throttle 20 (throttle valve) is provided in the pilot line 13 upstream (on the hydraulic pump side) of the tank line 17.
  • a pilot pressure control means is constituted by these components.
  • a pilot port of the bucket digging-side switching valve 18 is connected to the boom raising-side pilot line 14 through a control line 21.
  • a boom raising-side switching valve 22 as a hydraulic pilot valve whose degree of opening changes in accordance with an arm pulling pilot pressure.
  • pilot pressures P1, P2, and P3 proportional to operation quantities are exerted on pilot lines 13, 14, 15, and 16.
  • the switching valve 22 opens at a degree of opening proportional to the pilot pressure P3. Further, a pilot pressure P2a proportional to the degree of opening of the switching valve 22 is fed to the pilot port of the bucket digging-side switching valve 18, whereby the switching valve 18 opens at a degree of opening proportional to the pilot pressure P2a.
  • the bucket digging-side pilot pressure P1 is reduced to an intermediate pressure (e.g., one half or so) by the second throttle 20.
  • an intermediate pressure e.g., one half or so
  • valve stroke is diminished not by throttling an inlet-side passage of the bucket control valve 4 but by reducing the pilot pressure fed to the valve 4, to ensure a boom raising operation. Consequently, even in the event of decrease of the pump flow rate due to a lowering of the engine speed which is a pump drive source, the tank flow rate is also throttled at the same time by the valve 4. As a result, there no longer is any fear of occurrence of cavitation.
  • the construction can be made simpler than in case of providing a throttle means in the main passage. Accordingly, the cost of parts and that of assembly can be reduced and it becomes easy to later install the hydraulic circuit to an existing machine.
  • the bucket digging-side switching valve 18 When both boom raising and arm pulling operations are not performed substantially simultaneously, the bucket digging-side switching valve 18 does not operate, so that there is no throttling action for the bucket digging-side pilot pressure and a bucket digging operation is performed at a normal speed.
  • the degree of reduction in the bucket digging-side pilot pressure be adjustable in accordance with the weight of the bucket and the operator' s taste in operation characteristic.
  • adjustment of the degree of pressure reduction can be made by the selection and replacement of both throttles 19 and 20.
  • variable throttles are used as both first and second throttles 19' and 20'.
  • variable throttles when the bucket is replaced or the operator is changed in a single machine, the degree of pressure reduction can be adjusted freely by adjusting the degree of opening of both throttles 19' and 20'.
  • an electromagnetic proportional pressure reducing valve (hereinafter referred to simply as "pressure reducing valve") 23 is disposed in the bucket digging-side line 13, as shown in Fig. 3 .
  • pressure sensors 25 and 26 for detecting the boom raising pilot pressure P2 and the arm pulling pilot pressure P3 and sending them to a controller 24.
  • Secondary pressure command signals proportional to both pilot pressures P2 and P3 are sent to the pressure reducing valve 23 from the controller 24 to reduce the bucket digging-side pilot pressure.
  • steps S1 and S2 the boom raising pilot pressure P2 and the arm pulling pilot pressure P3 are read.
  • steps S3 and S4 it is respectively determined whether a boom raising operation and an arm pulling operation are being performed.
  • steps S5 and S6 the sum of both pilot pressures P2 and P3 is plotted along the axis of abscissa and a secondary pressure (pressure after reduction) of the pressure reducing valve 23 is plotted along the axis of ordinate, then on the basis of a preset throttle characteristic a secondary pressure command signal is outputted to the pressure reducing valve 23 as a proportional valve.
  • the selection and change of a characteristic with respect to each of boom raising, bucket digging, and arm pulling operations can be done more easily by adjustment (e.g., using a trimmer) through the controller 24.
  • pressure sensors 27 and 28 for detecting a boom raising-side (cylinder head) pressure of the boom cylinder 3 and an operating pressure (pump pressure) of the first hydraulic pump 1, as shown in Fig. 5 .
  • pump pressures detected by the pressure sensors 27 and 28 are inputted to the controller 24 and a bucket digging-side pilot pressure reducing action is exerted on the premise that the pump pressure is higher than the boom raising-side pressure.
  • the boom raising pilot pressure P2, arm pulling pilot pressure P3, boom cylinder pressure, and the pressure of the first hydraulic pump 1 are read in steps S1 to S4.
  • steps S5 and S6 it is determined whether a boom raising operation and an arm pulling operation are being performed or not. Thereafter, in step S7, a comparison is made between pump pressure and cylinder pressure. Only when the pump pressure is higher than the cylinder pressure, a secondary pressure of the pressure reducing valve as a proportional valve is calculated and outputted in steps S8 and S9.
  • a hydraulic pilot type pressure reducing valve as a pilot control means may be provided in the bucket digging-side pilot line 13.
  • electromagnetic switching valves are used as both bucket digging-side and boom raising-side switching valves 18, 22, and the switching valves 18 and 22 may be controlled by the controller in accordance with the boom raising-side pilot pressure and the arm pulling-side pilot pressure both detected by the pressure sensors.
  • the pressure oil provided from the first hydraulic pump 1 is used for both bucket cylinder and boom cylinder, while the pressure oil from the second hydraulic pump 6 is used for boom cylinder confluence and for the arm cylinder.
  • the present invention is also applicable to the case where the pressure oil from the second hydraulic pump 6 is not used for boom cylinder confluence.
  • the bucket digging-side pilot pressure may be reduced in accordance with the boom raising-side pilot pressure (a pressure raising operation quantity).
EP03256761A 2002-10-31 2003-10-27 Hydraulic excavator with a hydraulic circuit Expired - Lifetime EP1416096B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2002318556A JP3818252B2 (ja) 2002-10-31 2002-10-31 油圧ショベルの油圧回路
JP2002318556 2002-10-31

Publications (2)

Publication Number Publication Date
EP1416096A1 EP1416096A1 (en) 2004-05-06
EP1416096B1 true EP1416096B1 (en) 2010-10-06

Family

ID=32089592

Family Applications (1)

Application Number Title Priority Date Filing Date
EP03256761A Expired - Lifetime EP1416096B1 (en) 2002-10-31 2003-10-27 Hydraulic excavator with a hydraulic circuit

Country Status (4)

Country Link
EP (1) EP1416096B1 (ja)
JP (1) JP3818252B2 (ja)
AT (1) ATE483861T1 (ja)
DE (1) DE60334430D1 (ja)

Families Citing this family (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP4655795B2 (ja) 2005-07-15 2011-03-23 コベルコ建機株式会社 油圧ショベルの油圧制御装置
DE602007000412D1 (de) 2006-03-07 2009-02-12 Mazda Motor Heckteilaufbau eines Kraftfahrzeuges mit Seitenairbagvorrichtung
JP4931048B2 (ja) * 2006-07-31 2012-05-16 キャタピラー エス エー アール エル 作業機械の制御装置
JP5342293B2 (ja) * 2009-03-26 2013-11-13 住友建機株式会社 建設機械の油圧回路
JP5272211B2 (ja) * 2009-07-07 2013-08-28 住友建機株式会社 建設機械の油圧回路
JP5079827B2 (ja) * 2010-02-10 2012-11-21 日立建機株式会社 油圧ショベルの油圧駆動装置
JP5475507B2 (ja) * 2010-02-28 2014-04-16 住友建機株式会社 油圧ショベルの油圧制御装置
JP5406087B2 (ja) * 2010-03-18 2014-02-05 ヤンマー株式会社 作業車両の油圧回路
CN104838073B (zh) * 2012-11-23 2017-03-08 沃尔沃建造设备有限公司 用于控制工程机械的优先功能的设备和方法
WO2014148449A1 (ja) * 2013-03-22 2014-09-25 日立建機株式会社 建設機械の油圧駆動装置
US9394929B2 (en) * 2013-08-01 2016-07-19 Caterpillar Inc. Reducing dig force in hydraulic implements
JP6220228B2 (ja) * 2013-10-31 2017-10-25 川崎重工業株式会社 建設機械の油圧駆動システム
JP6196567B2 (ja) * 2014-03-06 2017-09-13 川崎重工業株式会社 建設機械の油圧駆動システム
JP7207060B2 (ja) * 2019-03-22 2023-01-18 コベルコ建機株式会社 作業機械の油圧駆動装置

Family Cites Families (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US172650A (en) * 1876-01-25 Improvement in hydraulic elevators
JP2607258B2 (ja) * 1988-03-30 1997-05-07 日立建機株式会社 作業機の油圧制御回路
JP2892939B2 (ja) * 1994-06-28 1999-05-17 日立建機株式会社 油圧掘削機の油圧回路装置
JP3612256B2 (ja) * 1999-12-22 2005-01-19 新キャタピラー三菱株式会社 作業機械の油圧回路
DE10047175A1 (de) * 2000-09-22 2002-04-11 Mannesmann Rexroth Ag Verfahren und Steueranordnung zur Ansteuerung von hydraulischen Verbrauchern
JP3901470B2 (ja) * 2001-05-15 2007-04-04 新キャタピラー三菱株式会社 流体圧回路の制御システム
JP2003232303A (ja) * 2002-02-12 2003-08-22 Shin Caterpillar Mitsubishi Ltd 流体圧回路

Also Published As

Publication number Publication date
JP3818252B2 (ja) 2006-09-06
EP1416096A1 (en) 2004-05-06
ATE483861T1 (de) 2010-10-15
JP2004150198A (ja) 2004-05-27
DE60334430D1 (de) 2010-11-18

Similar Documents

Publication Publication Date Title
EP1416096B1 (en) Hydraulic excavator with a hydraulic circuit
EP1743980B1 (en) Hydraulic excavator having a hydraulic control apparatus
US8726649B2 (en) Controller and work machine provided therewith
EP1790859A1 (en) Hydraulic controller for working machine
JPH11303809A (ja) 油圧駆動機械のポンプ制御装置
JPH02107802A (ja) 油圧駆動装置
JP2003004003A (ja) 油圧ショベルの油圧制御回路
JP3643193B2 (ja) 油圧モータの制御装置
JP3056220B2 (ja) 油圧駆動装置
JP2004360898A (ja) 作業機械の油圧制御装置
JPH10159809A (ja) 油圧アクチュエータの流量制御装置
JP2006177402A (ja) 建設機械の油圧回路
JP2004076904A (ja) 建設機械の油圧シリンダ制御装置
JP2010065733A (ja) 作業機械の油圧制御回路
JP3513172B2 (ja) 油圧制御装置
JP3097973B2 (ja) 油圧作業機の油圧回路
JP4432707B2 (ja) 建設機械の油圧制御回路
JP4003644B2 (ja) 作業機械の油圧制御装置
JP3175992B2 (ja) 油圧駆動機械の制御装置
JP4215409B2 (ja) 油圧駆動制御装置
JPH06221305A (ja) 建機の油圧回路構造
JP3723270B2 (ja) 油圧駆動機械の制御装置
JP2007092789A (ja) 建設機械の油圧制御装置
JP2758334B2 (ja) 建機の油圧回路構造
JP2945556B2 (ja) 建機の油圧回路構造

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

AK Designated contracting states

Kind code of ref document: A1

Designated state(s): AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HU IE IT LI LU MC NL PT RO SE SI SK TR

AX Request for extension of the european patent

Extension state: AL LT LV MK

17P Request for examination filed

Effective date: 20041020

AKX Designation fees paid

Designated state(s): AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HU IE IT LI LU MC NL PT RO SE SI SK TR

17Q First examination report despatched

Effective date: 20060918

GRAP Despatch of communication of intention to grant a patent

Free format text: ORIGINAL CODE: EPIDOSNIGR1

RTI1 Title (correction)

Free format text: HYDRAULIC EXCAVATOR WITH A HYDRAULIC CIRCUIT

GRAS Grant fee paid

Free format text: ORIGINAL CODE: EPIDOSNIGR3

GRAA (expected) grant

Free format text: ORIGINAL CODE: 0009210

AK Designated contracting states

Kind code of ref document: B1

Designated state(s): AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HU IE IT LI LU MC NL PT RO SE SI SK TR

REG Reference to a national code

Ref country code: GB

Ref legal event code: FG4D

REG Reference to a national code

Ref country code: CH

Ref legal event code: EP

REG Reference to a national code

Ref country code: IE

Ref legal event code: FG4D

REF Corresponds to:

Ref document number: 60334430

Country of ref document: DE

Date of ref document: 20101118

Kind code of ref document: P

REG Reference to a national code

Ref country code: NL

Ref legal event code: VDEP

Effective date: 20101006

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: SI

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20101006

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: DE

Payment date: 20101029

Year of fee payment: 8

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: GB

Payment date: 20101025

Year of fee payment: 8

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: AT

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20101006

Ref country code: PT

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20110207

Ref country code: MC

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20101031

Ref country code: NL

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20101006

Ref country code: FI

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20101006

Ref country code: BG

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20110106

Ref country code: SE

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20101006

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: IT

Payment date: 20101027

Year of fee payment: 8

REG Reference to a national code

Ref country code: CH

Ref legal event code: PL

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: BE

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20101006

Ref country code: GR

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20110107

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: CH

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20101031

Ref country code: ES

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20110117

Ref country code: CZ

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20101006

Ref country code: EE

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20101006

Ref country code: LI

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20101031

PLBE No opposition filed within time limit

Free format text: ORIGINAL CODE: 0009261

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: NO OPPOSITION FILED WITHIN TIME LIMIT

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: DK

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20101006

Ref country code: RO

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20101006

Ref country code: SK

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20101006

26N No opposition filed

Effective date: 20110707

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: IE

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20101027

REG Reference to a national code

Ref country code: DE

Ref legal event code: R097

Ref document number: 60334430

Country of ref document: DE

Effective date: 20110707

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: FR

Payment date: 20111103

Year of fee payment: 9

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: CY

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20101006

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: LU

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20101027

Ref country code: HU

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20110407

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: TR

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20101006

GBPC Gb: european patent ceased through non-payment of renewal fee

Effective date: 20121027

REG Reference to a national code

Ref country code: FR

Ref legal event code: ST

Effective date: 20130628

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: GB

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20121027

Ref country code: DE

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20130501

REG Reference to a national code

Ref country code: DE

Ref legal event code: R119

Ref document number: 60334430

Country of ref document: DE

Effective date: 20130501

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: FR

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20121031

Ref country code: IT

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20121027