EP1387089A2 - Circuit pour un vérin hydraulique - Google Patents

Circuit pour un vérin hydraulique Download PDF

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Publication number
EP1387089A2
EP1387089A2 EP03254648A EP03254648A EP1387089A2 EP 1387089 A2 EP1387089 A2 EP 1387089A2 EP 03254648 A EP03254648 A EP 03254648A EP 03254648 A EP03254648 A EP 03254648A EP 1387089 A2 EP1387089 A2 EP 1387089A2
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EP
European Patent Office
Prior art keywords
holding
valve
pressure
holding valve
opening
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.)
Withdrawn
Application number
EP03254648A
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German (de)
English (en)
Other versions
EP1387089A3 (fr
Inventor
Yutaka Kobelco Const. Machinery Co. Ltd. Toji
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
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Publication date
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Publication of EP1387089A2 publication Critical patent/EP1387089A2/fr
Publication of EP1387089A3 publication Critical patent/EP1387089A3/fr
Withdrawn legal-status Critical Current

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    • 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
    • F15B20/00—Safety arrangements for fluid actuator systems; Applications of safety devices in fluid actuator systems; Emergency measures for fluid actuator systems
    • F15B20/005—Leakage; Spillage; Hose burst
    • 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
    • E02F9/2296—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
    • F15B11/003—Systems with load-holding 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
    • F15B2211/20—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
    • F15B2211/30505—Non-return valves, i.e. check valves
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/30—Directional control
    • F15B2211/305—Directional control characterised by the type of valves
    • F15B2211/30505—Non-return valves, i.e. check valves
    • F15B2211/30515—Load holding valves
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/30—Directional control
    • F15B2211/305—Directional control characterised by the type of valves
    • F15B2211/30525—Directional control valves, e.g. 4/3-directional control valve
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/30—Directional control
    • F15B2211/305—Directional control characterised by the type of valves
    • F15B2211/3056—Assemblies of multiple valves
    • 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
    • F15B2211/3058—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 having additional valves for interconnecting the fluid chambers of a double-acting actuator, e.g. for regeneration mode or for floating mode
    • 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
    • F15B2211/31—Directional control characterised by the positions of the valve element
    • F15B2211/3138—Directional control characterised by the positions of the valve element the positions being discrete
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/30—Directional control
    • F15B2211/315—Directional control characterised by the connections of the valve or valves in the circuit
    • F15B2211/3157—Directional control characterised by the connections of the valve or valves in the circuit being connected to a pressure source, an output member and a return line
    • F15B2211/31576—Directional control characterised by the connections of the valve or valves in the circuit being connected to a pressure source, an output member and a return line having a single pressure source and a single output member
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/30—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
    • F15B2211/40—Flow control
    • F15B2211/405—Flow control characterised by the type of flow control means or valve
    • F15B2211/40515—Flow control characterised by the type of flow control means or valve with variable throttles or orifices
    • 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
    • F15B2211/40—Flow control
    • F15B2211/405—Flow control characterised by the type of flow control means or valve
    • F15B2211/40576—Assemblies of multiple valves
    • F15B2211/40584—Assemblies of multiple valves the flow control means arranged in parallel with a check 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
    • F15B2211/40—Flow control
    • F15B2211/41—Flow control characterised by the positions of the valve element
    • F15B2211/413—Flow control characterised by the positions of the valve element the positions being continuously variable, e.g. as realised by proportional 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
    • F15B2211/40—Flow control
    • F15B2211/415—Flow control characterised by the connections of the flow control means in the circuit
    • F15B2211/41527—Flow control characterised by the connections of the flow control means in the circuit being connected to an output member 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
    • F15B2211/40—Flow control
    • F15B2211/42—Flow control characterised by the type of actuation
    • F15B2211/421—Flow control characterised by the type of actuation mechanically
    • F15B2211/422—Flow control characterised by the type of actuation mechanically actuated by biasing means, e.g. spring-actuated
    • 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
    • F15B2211/40—Flow control
    • F15B2211/42—Flow control characterised by the type of actuation
    • F15B2211/428—Flow 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
    • F15B2211/40—Flow control
    • F15B2211/46—Control of flow in the return line, i.e. meter-out 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
    • F15B2211/50—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
    • F15B2211/80—Other types of control related to particular problems or conditions
    • F15B2211/86—Control during or prevention of abnormal conditions
    • F15B2211/863—Control during or prevention of abnormal conditions the abnormal condition being a hydraulic or pneumatic failure
    • F15B2211/8636—Circuit failure, e.g. valve or hose failure

Definitions

  • This invention relates to a hydraulic actuator circuit of a working machine.
  • a load on total weight of an attachment for an excavator and a load for carrying by the attachment acts in a direction of a cylinder contraction-side. In some cases, this leads to a problem of sudden lowering of the attachment on burst of a load-side pipeline in the boom cylinder and an oil leak in the control valve.
  • a holding valve (a safety valve) is provided (for example, Japanese Patent Application laid-open publications Hei 3-57507 and Hei 10-267009).
  • the acceleration test is as follows. In the circuit with the holding valve in a load-side pipeline of the boom cylinder, a load for the test which corresponds to a half of an actual rated lifting capacity is provided and then an actuating speed of the boom cylinder is set to 200 mm/sec. In this condition, on burst of the load-side pipeline, the actuating speed is measured as test result for a check. The test requires the actuating speed of less than twice (400 mm/sec) as high as the above set value.
  • the openings are described as the following equation (1).
  • the control valve opening A1 is determined on the basis of a standard that a target operability is accomplished in a machine without a holding valve. For this reason, in a machine with a holding valve and two openings A1, A2 connected in series, the larger A2 gets, the less the holding valve influences the operability. But, in order to pass the acceleration test, the opening A2 can not be overwhelmingly larger than the opening A1.
  • tuning the holding valve opening is hard to work, and, because of existence of inevitable manufacturing tolerances and variations arising while manufacturing the opening A2, the total opening A1+A2 is difficult to accomplish the same operability as that of only the opening A1.
  • the hydraulic actuator circuit of the present invention comprises, as a basic construction, a control valve which is operated by an operating means, a hydraulic actuator which is controlled by the control valve in accordance with an amount of operation of the operating means, and a holding valve disposed in a load-side pipeline of the hydraulic actuator and adapted to close the pipeline in a neutral state of the control valve, thereby holding a load.
  • the present invention is characterized by including a holding valve control means for controlling an opening of the holding valve during operation of the hydraulic actuator. According to the construction of the holding valve control means:
  • the holding valve opening is set to a value larger than the control valve opening in that condition, so that there is no fear of operability being influenced by the holding valve opening.
  • valve opening is set on the basis of the target operability, it is possible to ensure a desired operability and it is no longer required to perform such a troublesome work as adjusting the holding valve opening for attaining the target operability.
  • adjusting or tuning of the holding valve opening can be done independently without being influenced by the control valve opening and in a simple manner such that in the normal condition the holding valve opening is set sufficiently larger than the control valve opening, while in the unusual condition the holding valve opening is set only on the basis of only fulfilling the function as a safety valve.
  • the holding valve opening be set to a value sufficiently larger than the control valve opening.
  • the holding valve control means may be constructed such that the holding valve opening in the unusual condition is set to a value at which the actuator speed is lower than twice as high as that in the normal condition.
  • the holding valve opening can be set so that the foregoing desired actuator speed is lower than twice as high as that in the normal condition in conformity with the ISO Standard.
  • the holding valve is constructed so that its opening varies depending on the amount of operation of the operating means, and the holding valve control means is constructed to make control such that the amount of change in the opening of the holding valve based on the amount of operation of the operating means is varied in accordance with the holding pressure.
  • the amount of change in the holding valve opening relative to the amount of operation varies in accordance with the holding pressure.
  • the holding valve may be constructed as a hydraulic pilot valve whose opening changes in accordance with a pilot pressure based on operation of the operating means, while the holding valve control means may be constructed such that by adding to the holding valve the holding pressure in a direction in which the holding pressure is added to the pilot pressure, the amount of change in the holding valve opening relative to a command signal inputted from the exterior is changed on the basis of the holding pressure.
  • the holding valve control means is constructed such that the holding pressure is applied in a direction in which the pressure set for a return spring in the holding valve is decreased.
  • the holding valve control means is constructed so as to apply the holding pressure to a pilot port of the holding valve.
  • the holding valve control means has a pressure reducing valve disposed in a pilot line of the holding valve and is constructed so as to change the output of the pressure reducing valve in accordance with the holding pressure.
  • the holding valve control means is constructed so as to supply the holding pressure as a pilot pressure to the pressure reducing valve.
  • the holding pressure is applied to the hydraulic pilot type holding valve in a direction in which the holding pressure is added to the external pilot pressure and the change of the holding pressure is directly linked with the change of the holding valve opening, so that the operation of the holding valve is performed quickly and positively in comparison with a later-described construction wherein a holding pressure is detected by a sensor and the detected signal is converted to an oil pressure signal and applied to the holding valve, thus resulting in the apparatus reliability becoming higher.
  • the opening of the holding valve can basically be controlled by the operating means, it is possible to carry out for example an operation such that, after an unusual suspension of working attachment at a high position in the air, the actuator is operated while opening the holding valve gradually by operation of the operating means to bring down the attachment to a lower position.
  • the holding valve control means may include an electromagnetic proportional type pressure reducing valve disposed in the pilot line of the holding valve, a holding pressure sensor for detecting a holding pressure, and a controller which provides a command signal to the pressure reducing valve in accordance with a signal fed from the holding pressure sensor.
  • a load holding function (apparatus) in hydraulic actuator circuits embodying the present invention will be described hereinunder with reference to Figs. 1 to 9 in illustration of, but not in limitation of, the present invention.
  • the present invention is applicable to a hydraulic actuator circuit used in a hydraulic excavator and a working machine constituted using the hydraulic excavator as a matrix or a main body such as a dismantling machine or a deep hole excavator.
  • Numeral 11 denotes a boom cylinder as a hydraulic actuator
  • numeral 12 denotes a hydraulic pump as an oil pressure source
  • numeral 13 denotes a boom extension-side (load-side) conduit or pipeline
  • numeral 14 denotes a contraction-side conduit or pipeline
  • numeral 15 denotes a control valve
  • T denotes a tank.
  • a holding valve circuit H in a mounted state to the boom cylinder 11, the holding valve circuit H comprising a hydraulic pilot type holding valve 17, a check valve 18, a relief valve 19, and an assist cylinder 20.
  • the assist cylinder 20 is a holding valve control means disposed on a return spring 17a side of the holding valve 17.
  • the opening of the holding valve 17 changes together with that of the control valve 15 in accordance with the amount of operation of the remote control valve 16. For example, upon burst of the extension-side pipeline 13 in a neutral state of the control valve 15, the outflow of oil from the boom cylinder 11 to the extension-side pipeline 13 is inhibited by closure of the holding valve 17. As a result, contraction (load lowering) of the cylinder 11 is prevented.
  • the assist cylinder 20 comprises a piston rod 21 which contacts the return spring 17a and controls the pressure (a force resisting to the pilot pressure Pi, "spring set pressure” hereinafter) of the return spring, a first pressure chamber 22, and a second pressure chamber 23.
  • the pilot pressure Pi is introduced into the second pressure chamber 23, while a holding pressure Ph acting on the extension-side pipeline 13 is introduced into the first pressure chamber 22.
  • the first pressure chamber 22 pressurizes the piston rod 21 in a direction to weaken the spring set pressure, while the second pressure chamber 23 pressurizes the piston rod 21 in a direction to strengthen the spring set pressure.
  • the holding pressure Ph takes a value (determined by weight of the load of the boom cylinder 11) of not smaller than a first given value
  • the spring set pressure becomes low, so that the opening of the holding valve 17 becomes larger.
  • the spring set pressure becomes high, so that the opening of the holding valve 17 becomes smaller.
  • control valve opening In the normal condition the opening of the holding valve is set to a sufficiently larger value relative to a meter-out opening ( "control valve opening” hereinafter) of the control valve 15. In the unusual condition the opening of the holding valve is set to a value at which the cylinder speed becomes lower than that without the holding valve.
  • the opening of the holding valve is controlled so that, when the boom cylinder operating speed under a test load which corresponds to a half of an actual rated lifting capacity is set to 200 mm/sec, the cylinder speed in bursting the extension-side pipeline 13 of a boom cylinder 11 takes a value of less than twice (400 mm/sec) as high as the set value.
  • the holding valve opening A2 is controlled such that in the foregoing equation (1), when the speed of 200 mm/sec is ensured at the total opening A TOTAL and when there remains only the holding valve opening A2 due to burst of the load-side pipeline, the speed does not exceed the two-fold speed (400 mm/sec).
  • the holding valve opening A2 does not become an overwhelmingly larger opening relative to the control valve opening A1.
  • Fig. 2 illustrates how the control valve opening and the holding valve opening vary as the pilot pressure Pi changes and Fig. 3 illustrates a spool stroke of the holding valve 17 relative to changes of the pilot pressure Pi.
  • a dash-dot line I represents a holding valve opening characteristic in the normal condition
  • a dash-double dot line II represents a holding valve opening characteristic upon occurrence of burst
  • a solid line III represents a control valve opening characteristic.
  • the symbol A represents a value (the amount of operation of the remote control valve 16) of the pilot pressure Pi at which the cylinder speed becomes 200 mm/sec in the normal condition.
  • the holding valve opening takes the value at point x and the control valve opening takes the value at point z both in Fig. 2, and with the total opening at this time, the cylinder speed becomes 200 mm/sec.
  • the holding valve opening decreases to the point y in Fig. 2, and with the total opening at this time, the cylinder speed is suppressed to a value of smaller than 400 mm/sec.
  • the holding valve opening is narrowed to prevent an increase of the actuator speed. Therefore, by setting this holding valve opening in the unusual condition to a value which affords a desirable actuator speed (e.g., lower than twice as high as that in the normal condition), it is possible to prevent a sudden lowering of the working attachment in the working machine.
  • a desirable actuator speed e.g., lower than twice as high as that in the normal condition
  • the holding valve opening takes a sufficiently larger value than the control valve opening at that time.
  • the holding valve opening takes a sufficiently larger value than the control valve opening at that time.
  • tuning of the holding valve opening can be done independently without being influenced by the control valve opening and in a simple manner such that in the normal condition the holding valve opening is set sufficiently larger than the control valve opening, while in the unusual condition the holding valve opening is set on the basis of only fulfilling the safety valve function.
  • the holding valve opening can be controlled by the remote control valve 16. Therefore, for example when the attachment is suspended at a high position in the air upon occurrence of burst, the holding valve opening is expanded gradually by operation of the remote control valve 16, allowing the boom cylinder 11 to operate to its contraction side, whereby the attachment can be let down to a lower position.
  • the holding pressure Ph is applied to the holding valve 17 in a direction (spring set pressure weakening direction) in which it is added to the pilot pressure Pi to expand the holding valve opening, and thus a change of the holding pressure Ph is directly linked with a change of the holding valve opening. Consequently, the operation of the holding valve 17 is performed quickly and positively in comparison with for example the construction wherein the holding pressure Ph is detected with a sensor and the detected signal is converted to an oil pressure signal and applied to the holding valve, thus resulting in the apparatus reliability becoming higher.
  • a pressure reducing valve 24 is provided in the holding valve circuit H.
  • the pressure reducing valve 24 functions as a holding valve control means whose secondary pressure changes in accordance with the pilot pressure Pi.
  • the holding pressure Ph is reduced by the pressure reducing valve 24 and is then applied together with the pilot pressure Pi to the holding valve 17.
  • the holding pressure Ph is added to the pilot pressure Pi and acts in a direction to expand the holding valve opening.
  • the holding valve opening is set to a value sufficiently larger than the control valve opening, while in the unusual condition the holding valve opening is reduced.
  • Fig. 5 shows how the holding valve opening changes.
  • the secondary pressure in the pressure reducing valve is added to the pilot pressure Pi, resulting in the degree of increase of the holding valve opening (spool stroke) becoming larger.
  • the cylinder speed becomes 200 mm/sec at point A.
  • the holding valve opening takes a value sufficiently larger than the control valve opening.
  • the pilot pressure Pi introduced into the holding valve 17 is controlled in accordance with the holding pressure Ph.
  • a pressure reducing valve 25 is disposed in the pilot line of the holding valve 17.
  • the pressure reducing valve 25 functions as a holding valve control means whose secondary pressure varies depending on the holding pressure Ph.
  • the pilot pressure Pi drops upon lowering of the holding pressure Ph (upon occurrence of a trouble), whereby the ratio of an increase of the holding valve spool stroke relative to the amount of operation of the remote control valve decreases and the holding valve opening is reduced.
  • an electromagnetic proportional type pressure reducing valve 26 is disposed in the pilot line of the holding valve 17. Further provided are pressure sensors 27 and 28 for detecting the holding pressure Ph and the pilot pressure Pi, respectively. A secondary pressure Pi2 in the pressure reducing valve 26 is controlled a command signal provided from a controller 29 in accordance with pressure signals provided from both pressure sensors 27, 28.
  • step S3 when the detected holding pressure Ph exceeds a preset value PhS (NO in step S1 namely normal condition) and also when the pilot pressure Pi is not more than a preset value PiS (NO in step S2), the controller 29 sends a signal to the electromagnetic proportional valve 26 to set Pi equal to Pi2 (proportional valve secondary pressure) (step S3).
  • step S4 when the answer in step S1 is YES (Ph ⁇ PhS, namely unusual condition) and the answer in step S2 is also YES (Pi ⁇ PiS), the controller 29 sends a signal to the electromagnetic proportional valve 26 to reduce the secondary pressure Pi2 (step S4).
  • step S4 the ratio of a change in the proportional valve secondary pressure Pi2 relative to the pilot pressure Pi becomes gentler or smaller than in the normal condition (indicated with a dash-double dot line in the same step) and the holding valve opening is reduced.
  • a desired way of change of the holding valve opening relative to the change of the holding pressure Ph can be selected arbitrarily by a signal processing in the controller 29. Consequently, it becomes possible to enlarge the control range.
  • each of the above embodiments there basically is adopted a construction wherein the holding valve opening is controlled in accordance with the pilot pressure Pi of the remote control valve 16.
  • the holding valve opening is controlled (expanded in the normal condition and reduced in the unusual condition) in accordance with the holding pressure Ph alone independently of the pilot pressure Pi.
  • the holding valve 17 may be an electromagnetic valve which is controlled with an electric signal provided from the controller.
  • the present invention is applicable not only to the boom cylinder circuit but also to an arm cylinder circuit and the hydraulic actuator circuits (including a hydraulic motor circuit) in working machines (e.g., crane) other than the working machine and those using the hydraulic excavator as a matrix.
  • working machines e.g., crane
  • a hydraulic actuator circuit comprising a control valve which is operated by an operating means and which controls the operation of a hydraulic actuator in accordance with the amount of operation of the operating means, and a holding valve disposed in a load-side pipeline of the hydraulic actuator and whose opening varies in accordance with a signal inputted from its exterior such as a controller, the holding valve being closed in a neutral state of the control valve to hold a load, the hydraulic actuator circuit further comprising a holding valve control means for controlling the opening of the holding valve during operation of the hydraulic actuator, the holding valve control means being constructed such that:
  • the present invention it is possible to set the holding valve opening sufficiently larger than the control valve opening in the normal condition and thereby ensure the target operability while fulfilling the safety ensuring function inherent in the holding valve, that is, preventing a sudden lowering of load upon occurrence of a trouble such as burst in the load-side pipeline.
  • tuning of the holding valve opening can be done independently without being influenced by the control valve opening and in a simplified manner such that in the normal condition the holding valve opening is set sufficiently larger than the control valve opening, while in the unusual condition the holding valve opening is set only on the basis of fulfilling the function as a safety valve.

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  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Mechanical Engineering (AREA)
  • Mining & Mineral Resources (AREA)
  • Civil Engineering (AREA)
  • Structural Engineering (AREA)
  • Fluid-Pressure Circuits (AREA)
  • Analytical Chemistry (AREA)
  • Chemical & Material Sciences (AREA)
  • Operation Control Of Excavators (AREA)
  • Component Parts Of Construction Machinery (AREA)
EP03254648A 2002-07-30 2003-07-25 Circuit pour un vérin hydraulique Withdrawn EP1387089A3 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2002222000A JP3915622B2 (ja) 2002-07-30 2002-07-30 油圧アクチュエータ回路の負荷保持装置
JP2002222000 2002-07-30

Publications (2)

Publication Number Publication Date
EP1387089A2 true EP1387089A2 (fr) 2004-02-04
EP1387089A3 EP1387089A3 (fr) 2008-03-05

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ID=30112942

Family Applications (1)

Application Number Title Priority Date Filing Date
EP03254648A Withdrawn EP1387089A3 (fr) 2002-07-30 2003-07-25 Circuit pour un vérin hydraulique

Country Status (2)

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EP (1) EP1387089A3 (fr)
JP (1) JP3915622B2 (fr)

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1754682A1 (fr) * 2005-08-11 2007-02-21 HAWE Hydraulik GmbH & Co. KG Dispositif électrohydraulique
WO2017071584A1 (fr) * 2015-10-28 2017-05-04 民航协发机场设备有限公司 Système hydraulique de blocage d'essieu de navette bidirectionnelle
IT201600106112A1 (it) * 2016-10-21 2018-04-21 Atlantic Fluid Tech S R L Dispositivo anti-rottura tubo
EP3205888A4 (fr) * 2014-10-06 2018-06-27 KYB-YS Co., Ltd. Dispositif de régulation de pression de fluide
IT201800004555A1 (it) * 2018-04-16 2019-10-16 Dispositivo di protezione rottura tubo
CN111868338A (zh) * 2018-03-22 2020-10-30 住友重机械工业株式会社 挖土机
EP3862576A1 (fr) * 2020-02-10 2021-08-11 Robert Bosch GmbH Système de commande d'un cylindre d'actionnement d'une grue

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP4890147B2 (ja) * 2006-08-04 2012-03-07 日立建機株式会社 油圧アクチュエータ回路の負荷保持装置
JP5091034B2 (ja) * 2008-07-03 2012-12-05 日立建機株式会社 建設機械の油圧回路装置
JP5266150B2 (ja) * 2009-06-18 2013-08-21 太平電業株式会社 高圧油圧システム用油圧回路
JP6982517B2 (ja) * 2018-02-27 2021-12-17 Ｋｙｂ−Ｙｓ株式会社 流体圧制御装置
JP7171249B2 (ja) 2018-06-08 2022-11-15 株式会社アイチコーポレーション 高所作業車の安全装置

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0357507A (ja) 1989-07-26 1991-03-12 Kobe Steel Ltd 板圧延時の蛇行制御方法
JPH10267009A (ja) 1997-03-25 1998-10-06 Toshiba Mach Co Ltd 負荷保持切換弁装置

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH01133503U (fr) * 1988-03-03 1989-09-12
DE4342565A1 (de) * 1993-12-14 1995-06-22 Bosch Gmbh Robert Senkrechte hydraulische Arbeitsachse
JP3685923B2 (ja) * 1998-04-21 2005-08-24 日立建機株式会社 配管破断制御弁装置
US6173639B1 (en) * 1999-05-07 2001-01-16 Caterpillar Inc. Fluid control system having float control

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0357507A (ja) 1989-07-26 1991-03-12 Kobe Steel Ltd 板圧延時の蛇行制御方法
JPH10267009A (ja) 1997-03-25 1998-10-06 Toshiba Mach Co Ltd 負荷保持切換弁装置

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1754682A1 (fr) * 2005-08-11 2007-02-21 HAWE Hydraulik GmbH & Co. KG Dispositif électrohydraulique
EP3205888A4 (fr) * 2014-10-06 2018-06-27 KYB-YS Co., Ltd. Dispositif de régulation de pression de fluide
WO2017071584A1 (fr) * 2015-10-28 2017-05-04 民航协发机场设备有限公司 Système hydraulique de blocage d'essieu de navette bidirectionnelle
IT201600106112A1 (it) * 2016-10-21 2018-04-21 Atlantic Fluid Tech S R L Dispositivo anti-rottura tubo
EP3312436A1 (fr) * 2016-10-21 2018-04-25 Atlantic Fluid Tech S.r.l. Dispositif de tube anti-rupture
CN111868338A (zh) * 2018-03-22 2020-10-30 住友重机械工业株式会社 挖土机
CN111868338B (zh) * 2018-03-22 2022-07-26 住友重机械工业株式会社 挖土机
IT201800004555A1 (it) * 2018-04-16 2019-10-16 Dispositivo di protezione rottura tubo
EP3557083A1 (fr) * 2018-04-16 2019-10-23 Atlantic Fluid Tech S.r.l. Dispositif de protection de rupture de tube
EP3862576A1 (fr) * 2020-02-10 2021-08-11 Robert Bosch GmbH Système de commande d'un cylindre d'actionnement d'une grue

Also Published As

Publication number Publication date
JP3915622B2 (ja) 2007-05-16
JP2004060821A (ja) 2004-02-26
EP1387089A3 (fr) 2008-03-05

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