US20010054286A1 - Construction machine - Google Patents
Construction machine Download PDFInfo
- Publication number
- US20010054286A1 US20010054286A1 US09/833,625 US83362501A US2001054286A1 US 20010054286 A1 US20010054286 A1 US 20010054286A1 US 83362501 A US83362501 A US 83362501A US 2001054286 A1 US2001054286 A1 US 2001054286A1
- Authority
- US
- United States
- Prior art keywords
- arm
- switching valve
- oil
- rotating
- control
- 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.)
- Granted
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
- F15B11/17—Servomotor systems without provision for follow-up action; Circuits therefor with two or more servomotors using 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
- E02F9/2221—Control of flow rate; Load sensing arrangements
- E02F9/2225—Control of flow rate; Load sensing arrangements using pressure-compensating 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
- E02F9/2221—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
- E02F9/2278—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
- 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
- F15B2211/305—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
- F15B2211/3056—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
- F15B2211/31—Directional control characterised by the positions of the valve element
- F15B2211/3122—Special positions other than the pump port being connected to working ports or the working ports being connected to the return line
- F15B2211/3127—Floating position connecting the working ports and the return line
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
- F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
- F15B2211/00—Circuits for servomotor systems
- F15B2211/40—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
- F15B2211/455—Control of flow in the feed line, i.e. meter-in 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
- F15B2211/6316—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
- F15B2211/7142—Multiple output members, e.g. multiple hydraulic motors or cylinders the output members being arranged in multiple groups
-
- 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
- F15B2211/75—Control of speed 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
- the present invention relates to a construction machine such as a hydraulic excavator. Particularly, the invention relates to a hydraulic control circuit provided in the construction machine.
- the conventional hydraulic control circuit is designed so that oil is supplied from a common pump to a control valve for an arm and a control valve for rotating. Because of this, the arm, which has the smaller load, is first operated, so that the rotating operation is delayed.
- a rotating motor for causing a rotating operation such as a rotating operation of an upper rotating body.
- the arm operation comprises an operating such as arm pulling and arm-in, wherein “arm-in” means bringing in the excavator arm.
- Actuators include an arm cylinder for causing an excavator arm operation.
- Control valves control supply and discharge of oil between each of hydraulic pumps and each of the actuators.
- the control valves incline a control valve for a rotating motor and a control valve for an arm cylinder.
- a switching valve is switched between a first position for separately supplying oil from the hydraulic pumps to the control valve for the rotating motor and the control valve for the arm cylinder, and a second position for uniting and supplying oil from the hydraulic pumps.
- a detector outputs signals responsive to the rotating operation and the arm pulling operation respectively when those operations are carried out.
- a switching controller switches the switching valve to the second position when the signals are output substantially simultaneously.
- a meter-in flow-controller such as meter-in flow-control valve restricts a quantity of oil supplied to the arm cylinder when the switching valve is switched to the second position.
- the meter-in flow-controller restricts the quantity of oil supplied to the arm cylinder, so that the arm pulling speed can be suppressed. Accordingly, even if the rotating and arm pulling are operated simultaneously, respective operations of the rotating and the arm pulling can be done quickly, the delay of the rotating operation can be overcome, and the rotating and arm pulling operations can be realized properly.
- the meter-out flow controller is provided for restricting a quantity of oil discharged from the arm cylinder when the switching valve is switched to the second position.
- the meter-out flow controller when the quantity of oil supplied to the arm cylinder is throttled, the meter-out flow controller also simultaneously throttles the quantity of oil from the arm cylinder. Accordingly, cavitation can be prevented when, for example, the arm descends by its own weight without any operation.
- FIG. 1 is a hydraulic circuit view of a construction machine according to one embodiment of the present invention
- FIG. 2 is a meter-in throttle characteristic view of an arm cylinder shown in FIG. 1;
- FIG. 3 is likewise a meter-out throttle characteristic view
- FIG. 4 is a sectional view showing the constitution in which an adjusting valve for adjusting a meter-in flow rate is housed in an arm spool.
- FIG. 1 shows one embodiment where a hydraulic control circuit of the construction machine according to the present invention is applied to a hydraulic excavator.
- first hydraulic pump 2 when an engine 1 is driven, a first hydraulic pump 2 , a second hydraulic pump 3 and a pilot pump 4 are driven, respectively.
- the first and second hydraulic pumps 2 and 3 as plural pumps, are variable capacity type hydraulic pumps. These pumps are swash plate type axial piston pumps whose discharge flow rate changes on the basis of a displacement of an angle of inclination of a swash plate.
- Oil discharged from the first and second hydraulic pumps 2 and 3 is supplied to direction control valves arranged in a left center bypass line (sometimes abbreviated as LCB), and to direction control valves arranged in a right center bypass line (sometimes abbreviated as RCB).
- the control valves arranged in the LCB include a control valve 5 for a right traveling motor, a control valve 6 for a bucket cylinder and a control valve 7 for a boom cylinder.
- the control valves arranged in the RCB include a control valve for a left traveling motor 8 , a control valve 9 for a rotating motor and a control valve 10 for an arm cylinder.
- pilot pressure discharged from the pilot pump 4 is utilized as a pressure source Pa for various controls.
- a travel straight valve 11 as a switching valve is interposed in an upstream oil path L 1 of the control valve for the right traveling motor 5 .
- the travel straight valve 11 has a position a as a first position and a position b as a second position. Normally, it is held at the position a.
- oil discharged from the second hydraulic pump 3 flows to the oil paths L 1 and L 2 in parallel, and is supplied to the left and right control valves for a traveling motor 5 and 8 .
- oil discharged from the second hydraulic pump 3 is equally supplied to the left and right traveling motors. Accordingly, the travel straightness can be held.
- a cut valve 12 is provided downstream of the control valve for a boom cylinder 7 in the LCB.
- a cut valve 13 is provided downstream of the control valve for an arm cylinder 10 in the RCB.
- the cut valve 12 performs a closing operation when the control valve on the RCB side is operated.
- the cut valve 13 performs a closing operation when the control valves on the LCB side are operated.
- the reason is as follows: When the travel straight valve 11 is switched to the position a, oil discharged from the second hydraulic pump 3 is branched to the oil paths L 1 and L 2 . This is because when either of control valves on the RCB side is operated, pump pressure is not created unless the cut valve 12 on the LCB side is closed. On the other hand, when either of control valves on the LCB side is operated, pump pressure is not created unless the cut valve 13 on the RCB side is closed.
- the oil path L 3 is connected, at a united point P, to united oil path L 4 branched from downstream end of the control valve for a traveling motor 8 in the RCB. Oil is supplied to the control valve for a rotating motor 9 through an oil path L 5 extended from the united point P. Further, oil is supplied to the control valve for an arm cylinder 10 through oil paths L 6 and L 7 extended from the united point P. Numerals 14 and 15 in the oil paths L 3 and L 4 denote check valves. In the figure, numeral 9 a denotes a rotating motor for rotating an upper rotating body.
- a flow rate control valve 16 as meter-in flow-control valve for restricting or throttling a quantity of oil in a meter-in circuit in the control valve for an arm cylinder 10 .
- the flow rate control valve 16 is controlled by a controller 17 as a switching control means.
- a flow rate control valve 18 as meter-out flow-control valve for throttling a quantity of oil in a meter-out circuit in the control valve for an arm cylinder 10 . It is likewise controlled by the controller 17 .
- An oil path L 9 downstream of the flow rate control valve 18 is fed back to a head-side oil chamber of an arm cylinder 19 through a check valve 18 a . This constitutes a reproducing circuit for increasing an arm speed.
- numeral 20 denotes an arm-push united valve for accelerating arm-pushing.
- numeral 50 denotes a boom-lift united valve for accelerating boom-lifting.
- the meter-in circuit and the meter-out circuit are so designed as to be throttled or restricted respectively when the rotating and the arm-pulling are operated simultaneously.
- the throttling effect depends on an inflow flow rate of oil.
- the inflow flow rate depends on a rotational frequency of an engine. Accordingly, when the rotational frequency of the engine falls to lower the quantity of discharge of the pump, the throttling effect lowers.
- FIG. 2 shows a characteristic view of the meter-in throttle hydraulic signal P in .
- the meter-in throttle hydraulic signal P in output from the solenoid proportional valve 21 that is, the so called proportional valve secondary pressure
- P a1 to P amax increases from P a1 to P amax .
- the characteristics is lowered from M 1 to M 5 stepwise until the maximum secondary pressure assumes a pressure P a2 according to the decrease of the rotational frequency of the engine. Thereby, the throttling effect is relieved stepwise.
- FIG. 3 shows a characteristic view of a meter-out throttle hydraulic signal P out .
- the meter-out throttle hydraulic signal P out output from the solenoid proportional valve 28 that is, the so called proportional valve secondary pressure, increases from P a1 to P a2 .
- the characteristic pressure is increased from S 1 to S 3 stepwise till the maximum secondary pressure assumes a value according to decrease of the rotational frequency of the engine, conversely to the characteristics shown in FIG. 2. Thereby, cavitations can be prevented.
- FIG. 4 shows the constitution in which the flow rate control valve 16 is housed in the control valve 10 for an arm cylinder.
- a bore 31 extends through a housing 30 .
- An arm spool 32 and an auxiliary arm spool for throttling 41 constituting a flow rate control valve 16 are slidably inserted into the bore 31 and in the outer periphery of the arm spool 32 , respectively.
- the housing 30 is internally formed with pump ports 33 a , 33 b connected to the hydraulic pump, bleed-off ports 34 , 35 constituting the center bypass passage RCB, and a tank port 36 . Oil introduced from the pump port 33 a is discharged from the head port 37 and supplied to a head-side oil chamber 19 a of the arm cylinder 19 .
- Oil discharged from a rod-side oil chamber 19 b of the arm cylinder 19 is introduced into the rod port 38 and discharged from a reproducing port 39 . Then the oil is supplied to the head-side oil chamber 19 a through the flow rate control valve 18 .
- a pilot port 40 into which is introduced a meter-in throttle hydraulic signal P in from the solenoid proportional valve 27 .
- the auxiliary spool 41 is operated by the signal P in so as to throttle the meter-in flow rate of the inflow flow rate.
- remote control pressure of the remote control valve for rotating 22 in place of a hydraulic signal from the solenoid proportional valve 27 may be input into the port 40 directly.
- an operator simultaneously operates the remote control valve for an arm 21 and the remote control valve for rotating 22 to simultaneously start arm pulling and rotating.
- an arm pulling signal P 1 and a rotating signal P 2 are respectively output from a pressure sensor 23 and a pressure sensor 24 as detection means for detecting remote control pressure and applied to the controller 17 .
- the controller 17 judges if both the signals P 1 and P 2 are input, to thereby recognize simultaneous operation of arm pulling and rotating.
- a united signal P 3 is output to the solenoid proportional valve 25 .
- the solenoid proportional valve 25 applies a switching hydraulic signal P 4 to the control port of the travel straight valve 11 to switch the travel straight valve 11 from the position a to the position b.
- a united signal P 5 is output to the solenoid proportional valve 26 .
- the solenoid proportional valve 26 switches the cut valve 12 from a position c (open) to a position d (closed).
- the oil discharged from the second hydraulic pump 3 is branched to the oil path L 2 also.
- the oil further flows into the united oil path L 4 through the center bypass of the control valve for a left traveling motor 8 . Accordingly, oil flows of both the hydraulic pumps 2 and 3 are united at the united point P. However, it is assumed that the control valves on the LCB are not operated.
- the meter-in flow controller and the meter-out flow controller are designed so that the quantity of oil supplied to the arm cylinder is restricted according to the amplitude of a signal output by the rotating operation. Therefore, the quantity of oil supplied to the rotating motor and the arm cylinder in the simultaneous operation of rotating and arm pulling can be kept to the desired ratio. Accordingly, even an unskilled person can perform the rotating and arm pulling operations simply.
- the meter-in flow-controller and the meter-out flow-controller are designed so that the restriction characteristics can be changed according to the rotational frequency of the engine. Therefore, the fixed restricting effect corresponding to the variation of the rotational frequency of the engine is obtained. Thereby, cavitation can be prevented.
- the travel straight valve 11 in realizing a circuit capable of simultaneously operating the rotating and arm pulling, the travel straight valve 11 is utilized.
- the flow rate control valve 16 for throttling the meter-in circuit of the arm cylinder 19 can be constituted by changing a land shape of an arm spool.
- traveling motors as actuators
- traveling control valves for controlling both traveling motors as control valves.
- a hydraulic control circuit of a construction machine using, as a switching valve, a traveling control valve which is switched between a first position for independently supplying oil from separate hydraulic pumps to both traveling control valves and a second position for supplying oil from a singe hydraulic pump in parallel.
- the hydraulic control circuit of the present invention has been described taking a hydraulic excavator as an example, the invention is not limited thereto.
- the invention can be applied to a suitable construction machine, which is provided with an arm and turns an upper rotating body.
Landscapes
- Engineering & Computer Science (AREA)
- General Engineering & Computer Science (AREA)
- Mining & Mineral Resources (AREA)
- Civil Engineering (AREA)
- Structural Engineering (AREA)
- Physics & Mathematics (AREA)
- Fluid Mechanics (AREA)
- Mechanical Engineering (AREA)
- Operation Control Of Excavators (AREA)
- Fluid-Pressure Circuits (AREA)
Abstract
Description
- The present application is based on Japanese patent application 2000-112340 filed on Apr. 13, 2000, which is herein incorporated by reference.
- 1. Field of the Invention
- The present invention relates to a construction machine such as a hydraulic excavator. Particularly, the invention relates to a hydraulic control circuit provided in the construction machine.
- 2. Description of the Background
- In the past, where excavation work is carried out by a hydraulic excavator, earth and sand scooped by a bucket are loaded on a dump truck waiting behind the hydraulic excavator by rotating an upper rotating body of the excavator. The operation is carried such that when loading onto the dump truck is terminated, an excavator arm is turned while elevated, and returned to an excavation point.
- The conventional hydraulic control circuit is designed so that oil is supplied from a common pump to a control valve for an arm and a control valve for rotating. Because of this, the arm, which has the smaller load, is first operated, so that the rotating operation is delayed.
- In this case, an operator has to carry out a complicated operation in which an arm operating lever is operated moderately, to provide sufficient oil pressure for the rotating operation. The complicated operation is difficult to do unless an operator is a skilled person. However, when pulling and rotating of the arm are carried out while adjusting an operating lever, there occurs a problem that rerotating to the excavation point is delayed to lower the work efficiency.
- To cope with the foregoing, control has been carried out so that a valve for throttling a quantity of oil discharged from an arm cylinder at the time of an arm pulling operation is provided to overcome the delay of the rotating operation during the arm pulling operation. However, in this hydraulic control circuit, since the valve is provided in a circuit on the rod side of an arm cylinder, even if throttling is done relatively strongly, a sufficient throttling effect could not be a obtained. The digging equipment herein denoted in simplified manner as an “excavator arm,” as a rule comprises an integral single boom or a boom in two parts, plus a shovel stem and an excavating implement.
- It is an object of the present invention to provide a construction machine capable of carrying out a rotating operation and an excavator arm operation properly even if both the rotating and the arm pulling are operated simultaneously.
- In accordance with at least an aspect of the invention, the above and other objects are addressed by a rotating motor for causing a rotating operation such as a rotating operation of an upper rotating body. The arm operation comprises an operating such as arm pulling and arm-in, wherein “arm-in” means bringing in the excavator arm. Actuators include an arm cylinder for causing an excavator arm operation. Control valves control supply and discharge of oil between each of hydraulic pumps and each of the actuators. The control valves incline a control valve for a rotating motor and a control valve for an arm cylinder. A switching valve is switched between a first position for separately supplying oil from the hydraulic pumps to the control valve for the rotating motor and the control valve for the arm cylinder, and a second position for uniting and supplying oil from the hydraulic pumps. A detector outputs signals responsive to the rotating operation and the arm pulling operation respectively when those operations are carried out. A switching controller switches the switching valve to the second position when the signals are output substantially simultaneously. A meter-in flow-controller such as meter-in flow-control valve restricts a quantity of oil supplied to the arm cylinder when the switching valve is switched to the second position.
- In this case, when rotating and arm pulling are operated simultaneously, signals are respectively output from the detector and applied to the switching controller. The switching controller recognizes that the signals are output simultaneously, and switches the switching valve to the second position. When the switching valve is switched to the second position, oil flows discharged from the plurality of hydraulic pumps are united and supplied to the rotating motor and the arm cylinder through a specific control valve. Accordingly, the quantity of oil supplied to the rotating motor and the arm cylinder is increased. Thereby, the quantity of oil necessary for quickly carrying out the rotating and arm pulling operations is secured.
- In this state, the meter-in flow-controller restricts the quantity of oil supplied to the arm cylinder, so that the arm pulling speed can be suppressed. Accordingly, even if the rotating and arm pulling are operated simultaneously, respective operations of the rotating and the arm pulling can be done quickly, the delay of the rotating operation can be overcome, and the rotating and arm pulling operations can be realized properly.
- Preferably, the meter-out flow controller is provided for restricting a quantity of oil discharged from the arm cylinder when the switching valve is switched to the second position.
- In this case, when the quantity of oil supplied to the arm cylinder is throttled, the meter-out flow controller also simultaneously throttles the quantity of oil from the arm cylinder. Accordingly, cavitation can be prevented when, for example, the arm descends by its own weight without any operation.
- FIG. 1 is a hydraulic circuit view of a construction machine according to one embodiment of the present invention;
- FIG. 2 is a meter-in throttle characteristic view of an arm cylinder shown in FIG. 1;
- FIG. 3 is likewise a meter-out throttle characteristic view; and
- FIG. 4 is a sectional view showing the constitution in which an adjusting valve for adjusting a meter-in flow rate is housed in an arm spool.
- The present invention will be described in detail hereinafter on the basis of one embodiment of the invention shown in the drawings.
- FIG. 1 shows one embodiment where a hydraulic control circuit of the construction machine according to the present invention is applied to a hydraulic excavator.
- In the figure, when an engine1 is driven, a first hydraulic pump 2, a second hydraulic pump 3 and a
pilot pump 4 are driven, respectively. The first and second hydraulic pumps 2 and 3, as plural pumps, are variable capacity type hydraulic pumps. These pumps are swash plate type axial piston pumps whose discharge flow rate changes on the basis of a displacement of an angle of inclination of a swash plate. - Oil discharged from the first and second hydraulic pumps2 and 3 is supplied to direction control valves arranged in a left center bypass line (sometimes abbreviated as LCB), and to direction control valves arranged in a right center bypass line (sometimes abbreviated as RCB). The control valves arranged in the LCB include a
control valve 5 for a right traveling motor, acontrol valve 6 for a bucket cylinder and a control valve 7 for a boom cylinder. The control valves arranged in the RCB include a control valve for a left travelingmotor 8, acontrol valve 9 for a rotating motor and acontrol valve 10 for an arm cylinder. - Further, pilot pressure discharged from the
pilot pump 4 is utilized as a pressure source Pa for various controls. - A travel
straight valve 11 as a switching valve is interposed in an upstream oil path L1 of the control valve for the right travelingmotor 5. The travelstraight valve 11 has a position a as a first position and a position b as a second position. Normally, it is held at the position a. - At the position a, oil discharged from the first hydraulic pump2 is supplied to the LCB side through the oil path L1. On the other hand, oil discharged from the second hydraulic pump 3 is supplied to the RCB side through the oil path L2. Accordingly, oil is supplied respectively from the first hydraulic pump 2 and the second hydraulic pump 3 to the control valve for a right traveling
motor 5 and the control valve for a left travelingmotor 8. - For example, when the boom or the arm is operated in the state that the left and right operating levers (not shown in the figure) are operated to the same position, the travel
straight valve 11 is switched from the position a to the position b. Oil discharged from the first hydraulic pump 2 is distributed and supplied to the control valve for a rotatingmotor 9, and the control valve for anarm cylinder 10 through the oil path L3. - At that time, oil discharged from the second hydraulic pump3 flows to the oil paths L1 and L2 in parallel, and is supplied to the left and right control valves for a traveling
motor - Further, a
cut valve 12 is provided downstream of the control valve for a boom cylinder 7 in the LCB. On the other hand, acut valve 13 is provided downstream of the control valve for anarm cylinder 10 in the RCB. - The
cut valve 12 performs a closing operation when the control valve on the RCB side is operated. On the other hand, thecut valve 13 performs a closing operation when the control valves on the LCB side are operated. The reason is as follows: When the travelstraight valve 11 is switched to the position a, oil discharged from the second hydraulic pump 3 is branched to the oil paths L1 and L2. This is because when either of control valves on the RCB side is operated, pump pressure is not created unless thecut valve 12 on the LCB side is closed. On the other hand, when either of control valves on the LCB side is operated, pump pressure is not created unless thecut valve 13 on the RCB side is closed. - The oil path L3 is connected, at a united point P, to united oil path L4 branched from downstream end of the control valve for a traveling
motor 8 in the RCB. Oil is supplied to the control valve for arotating motor 9 through an oil path L5 extended from the united point P. Further, oil is supplied to the control valve for anarm cylinder 10 through oil paths L6 and L7 extended from the unitedpoint P. Numerals - In the oil path L7, there is provided a flow
rate control valve 16 as meter-in flow-control valve for restricting or throttling a quantity of oil in a meter-in circuit in the control valve for anarm cylinder 10. The flowrate control valve 16 is controlled by acontroller 17 as a switching control means. - Further, in an oil path L8 downstream of the control valve for an
arm cylinder 10, there is provided a flowrate control valve 18 as meter-out flow-control valve for throttling a quantity of oil in a meter-out circuit in the control valve for anarm cylinder 10. It is likewise controlled by thecontroller 17. An oil path L9 downstream of the flowrate control valve 18 is fed back to a head-side oil chamber of anarm cylinder 19 through acheck valve 18 a. This constitutes a reproducing circuit for increasing an arm speed. In the figure, numeral 20 denotes an arm-push united valve for accelerating arm-pushing. Likewise, numeral 50 denotes a boom-lift united valve for accelerating boom-lifting. - The meter-in circuit and the meter-out circuit are so designed as to be throttled or restricted respectively when the rotating and the arm-pulling are operated simultaneously. The throttling effect depends on an inflow flow rate of oil. The inflow flow rate depends on a rotational frequency of an engine. Accordingly, when the rotational frequency of the engine falls to lower the quantity of discharge of the pump, the throttling effect lowers. Therefore, where a solenoid
proportional valve 27 for applying a meter-in throttle hydraulic signal Pin to the flowrate control valve 16 and a solenoidproportional valve 28 for applying a meter-out throttle signal Pout to the flowrate control valve 18 are controlled, throttle signals P6 and P7 according to the rotational frequency of the engine are commanded from thecontroller 17. - FIG. 2 shows a characteristic view of the meter-in throttle hydraulic signal Pin. In the operating range in which rotating remote control pressure P1 of a remote control valve for rotating 22 changes from Pla to Plb, when the engine is rated-operated, the meter-in throttle hydraulic signal Pin output from the solenoid
proportional valve 21, that is, the so called proportional valve secondary pressure, increases from Pa1 to Pamax. As the rotational frequency of the engine falls, the characteristics is lowered from M1 to M5 stepwise until the maximum secondary pressure assumes a pressure Pa2 according to the decrease of the rotational frequency of the engine. Thereby, the throttling effect is relieved stepwise. - FIG. 3 shows a characteristic view of a meter-out throttle hydraulic signal Pout. In the operating range in which remote control pressure P1 changes from Pla to Plb when the engine is rated-operated, the meter-out throttle hydraulic signal Pout output from the solenoid
proportional valve 28, that is, the so called proportional valve secondary pressure, increases from Pa1 to Pa2. As the rotational frequency of the engine falls, the characteristic pressure is increased from S1 to S3 stepwise till the maximum secondary pressure assumes a value according to decrease of the rotational frequency of the engine, conversely to the characteristics shown in FIG. 2. Thereby, cavitations can be prevented. - In the above-described constitution, when the remote control pressure rises, the proportional secondary pressure rises in proportion thereto and the flow
rate control valve 16 is throttled. Alternatively, an inverse proportion may be made in which when the rotating remote control pressure rises, the proportional secondary pressure falls and the flowrate control valve 16 is throttled. - FIG. 4 shows the constitution in which the flow
rate control valve 16 is housed in thecontrol valve 10 for an arm cylinder. - In the figure, a
bore 31 extends through ahousing 30. Anarm spool 32 and an auxiliary arm spool for throttling 41 constituting a flowrate control valve 16 are slidably inserted into thebore 31 and in the outer periphery of thearm spool 32, respectively. Thehousing 30 is internally formed withpump ports ports tank port 36. Oil introduced from thepump port 33 a is discharged from thehead port 37 and supplied to a head-side oil chamber 19 a of thearm cylinder 19. Oil discharged from a rod-side oil chamber 19 b of thearm cylinder 19 is introduced into therod port 38 and discharged from a reproducingport 39. Then the oil is supplied to the head-side oil chamber 19 a through the flowrate control valve 18. - On the right hand side of the
housing 30, there is provided apilot port 40 into which is introduced a meter-in throttle hydraulic signal Pin from the solenoidproportional valve 27. Theauxiliary spool 41 is operated by the signal Pin so as to throttle the meter-in flow rate of the inflow flow rate. Alternately, remote control pressure of the remote control valve for rotating 22 in place of a hydraulic signal from the solenoidproportional valve 27 may be input into theport 40 directly. - As described above, according to the constitution in which the flow
rate control valve 16 for throttling a meter-in circuit is housed in the control valve for anarm cylinder 10, the hydraulic circuit becomes simple, and the space is also saved. - In the following, the operation of the hydraulic control circuit having the above-described constitution will be described. In the following description of operation, a description will be made of a case where after earth and sand are loaded on the dump truck, the arm is rotated while being elevated, and returned to the excavation point.
- An operator simultaneously operates the remote control valve for an
arm 21 and the remote control valve for rotating 22 to simultaneously start arm pulling and rotating. At that time, an arm pulling signal P1 and a rotating signal P2 are respectively output from apressure sensor 23 and apressure sensor 24 as detection means for detecting remote control pressure and applied to thecontroller 17. - The
controller 17 judges if both the signals P1 and P2 are input, to thereby recognize simultaneous operation of arm pulling and rotating. When the simultaneous operation is recognized, a united signal P3 is output to the solenoidproportional valve 25. The solenoidproportional valve 25 applies a switching hydraulic signal P4 to the control port of the travelstraight valve 11 to switch the travelstraight valve 11 from the position a to the position b. - At the same time, a united signal P5 is output to the solenoid
proportional valve 26. The solenoidproportional valve 26 switches thecut valve 12 from a position c (open) to a position d (closed). - At that time, oil discharged from the first hydraulic pump2 is supplied to the RCB through the passage L3. On the other hand, oil discharged from the second hydraulic pump 3 is supplied to the LCB through the passage L1.
- The oil discharged from the second hydraulic pump3 is branched to the oil path L2 also. The oil further flows into the united oil path L4 through the center bypass of the control valve for a left traveling
motor 8. Accordingly, oil flows of both the hydraulic pumps 2 and 3 are united at the united point P. However, it is assumed that the control valves on the LCB are not operated. - In this state, the operating levers of the remote control valve for an
arm 21 and the remote control valve for rotating 22 are deeply operated. At that time, an increase in operating pressure in the remote control valve for rotating 22 is detected by thepressure sensor 24 and applied to thecontroller 17. Thecontroller 17 outputs throttle signals P6 and P7 according to operating pressures detected to the solenoidproportional valves rate control valves arm cylinder 10 are throttled to prevent the oil united at the united point P from preferentially flowing to the control valve for anarm cylinder 10. Accordingly, the control valve for arotating motor 9 and the control valve for anarm cylinder 10 can be operated properly. - Further, where the rotational frequency of the engine falls to lower the discharge quantity of the pump, the following operation for preventing the lowering of the throttling effect is carried out, as mentioned above. That is, the throttling of the meter-in circuit is relieved according to the rotational frequency of the engine, and the throttling of he meter-out circuit is increased. Thereby, cavitation is prevented.
- According to the embodiments of the present invention, the meter-in flow controller and the meter-out flow controller are designed so that the quantity of oil supplied to the arm cylinder is restricted according to the amplitude of a signal output by the rotating operation. Therefore, the quantity of oil supplied to the rotating motor and the arm cylinder in the simultaneous operation of rotating and arm pulling can be kept to the desired ratio. Accordingly, even an unskilled person can perform the rotating and arm pulling operations simply.
- Further, the meter-in flow-controller and the meter-out flow-controller are designed so that the restriction characteristics can be changed according to the rotational frequency of the engine. Therefore, the fixed restricting effect corresponding to the variation of the rotational frequency of the engine is obtained. Thereby, cavitation can be prevented.
- In the present embodiment, in realizing a circuit capable of simultaneously operating the rotating and arm pulling, the travel
straight valve 11 is utilized. However, the effect of the present invention is exhibited even with a different circuit for providing the united oil path L4. The flowrate control valve 16 for throttling the meter-in circuit of thearm cylinder 19 can be constituted by changing a land shape of an arm spool. - That is, in the present embodiment, there are left and right traveling motors as actuators, and both traveling control valves for controlling both traveling motors as control valves. Further, there is provided a hydraulic control circuit of a construction machine using, as a switching valve, a traveling control valve which is switched between a first position for independently supplying oil from separate hydraulic pumps to both traveling control valves and a second position for supplying oil from a singe hydraulic pump in parallel.
- While in the present embodiment, the hydraulic control circuit of the present invention has been described taking a hydraulic excavator as an example, the invention is not limited thereto. The invention can be applied to a suitable construction machine, which is provided with an arm and turns an upper rotating body.
- While one embodiment of the present invention has been disclosed, the scope of protection of the present invention is not limited thereto.
- Obviously, numerous modifications and variations of the present invention are possible in light of the above teachings. It is therefore to be understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described herein.
Claims (9)
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2000-112340 | 2000-04-13 | ||
JP2000112340A JP3491600B2 (en) | 2000-04-13 | 2000-04-13 | Hydraulic control circuit for construction machinery |
Publications (2)
Publication Number | Publication Date |
---|---|
US20010054286A1 true US20010054286A1 (en) | 2001-12-27 |
US6430922B2 US6430922B2 (en) | 2002-08-13 |
Family
ID=18624529
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US09/833,625 Expired - Fee Related US6430922B2 (en) | 2000-04-13 | 2001-04-13 | Construction machine |
Country Status (5)
Country | Link |
---|---|
US (1) | US6430922B2 (en) |
EP (1) | EP1146175B1 (en) |
JP (1) | JP3491600B2 (en) |
AT (1) | ATE330075T1 (en) |
DE (1) | DE60120545T2 (en) |
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN103375449A (en) * | 2012-04-23 | 2013-10-30 | 住友建机株式会社 | Hydraulic loop for mechanical construction and hydraulic control device thereof |
US20140105714A1 (en) * | 2011-05-11 | 2014-04-17 | Volvo Construction Equipment Ab | Hybrid excavator including a fast-stopping apparatus for a hybrid actuator |
US20140345268A1 (en) * | 2011-12-15 | 2014-11-27 | Volvo Construction Equipment Ab | Travel control system for construction machinery |
US9988792B2 (en) | 2013-01-17 | 2018-06-05 | Jiangsu Hengli Highpressure Oil Cylinder Co., Ltd. | Hydraulic apparatus based on confluence control mode |
Families Citing this family (29)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6612109B2 (en) * | 2001-12-20 | 2003-09-02 | Case Corporation | Hydraulic power boost system for a work vehicle |
KR100518770B1 (en) * | 2003-02-12 | 2005-10-05 | 볼보 컨스트럭션 이키프먼트 홀딩 스웨덴 에이비 | hydraulic system of heavy equipment option device |
JP4062160B2 (en) * | 2003-04-23 | 2008-03-19 | コベルコ建機株式会社 | Hydraulic valve device |
US20050081518A1 (en) * | 2003-10-20 | 2005-04-21 | Pengfei Ma | Flow-control apparatus for controlling the swing speed of a boom assembly |
US7178333B2 (en) * | 2004-03-18 | 2007-02-20 | Kobelco Construction Machinery Co., Ltd. | Hydraulic control system for hydraulic excavator |
JP2006070970A (en) * | 2004-09-01 | 2006-03-16 | Shin Caterpillar Mitsubishi Ltd | Hydraulic control circuit for construction machine |
KR101144396B1 (en) * | 2004-12-16 | 2012-05-11 | 두산인프라코어 주식회사 | Hydraulic control system in the swing combined motion of an excavator |
JP4262213B2 (en) * | 2005-03-14 | 2009-05-13 | ヤンマー株式会社 | Backhoe loader hydraulic circuit |
JP2006329341A (en) * | 2005-05-26 | 2006-12-07 | Kobelco Contstruction Machinery Ltd | Hydraulic control unit of working machine |
JP2007032790A (en) * | 2005-07-29 | 2007-02-08 | Shin Caterpillar Mitsubishi Ltd | Fluid pressure controller, fluid pressure control method, and hydraulic controller |
JP4232784B2 (en) * | 2006-01-20 | 2009-03-04 | コベルコ建機株式会社 | Hydraulic control device for work machine |
JP4353190B2 (en) * | 2006-02-27 | 2009-10-28 | コベルコ建機株式会社 | Hydraulic circuit for construction machinery |
KR100753990B1 (en) * | 2006-08-29 | 2007-08-31 | 볼보 컨스트럭션 이키프먼트 홀딩 스웨덴 에이비 | Hydraulic circuit for traveling straight |
KR100906228B1 (en) * | 2007-03-30 | 2009-07-07 | 볼보 컨스트럭션 이키프먼트 홀딩 스웨덴 에이비 | Hydraulic circuit of construction equipment |
JP5066987B2 (en) | 2007-04-10 | 2012-11-07 | コベルコ建機株式会社 | Hydraulic control device of excavator |
KR100900436B1 (en) * | 2007-05-21 | 2009-06-01 | 볼보 컨스트럭션 이키프먼트 홀딩 스웨덴 에이비 | Traveling device of heavy equipment crawler type |
JP5079827B2 (en) * | 2010-02-10 | 2012-11-21 | 日立建機株式会社 | Hydraulic drive device for hydraulic excavator |
JP5758348B2 (en) * | 2012-06-15 | 2015-08-05 | 住友建機株式会社 | Hydraulic circuit for construction machinery |
JP5778086B2 (en) * | 2012-06-15 | 2015-09-16 | 住友建機株式会社 | Hydraulic circuit of construction machine and its control device |
JP5978056B2 (en) * | 2012-08-07 | 2016-08-24 | 住友建機株式会社 | Hydraulic circuit of construction machine and its control device |
US20150059325A1 (en) * | 2013-09-03 | 2015-03-05 | Caterpillar Inc. | Hybrid Apparatus and Method for Hydraulic Systems |
JP6220228B2 (en) * | 2013-10-31 | 2017-10-25 | 川崎重工業株式会社 | Hydraulic drive system for construction machinery |
WO2016080760A1 (en) * | 2014-11-20 | 2016-05-26 | 두산인프라코어 주식회사 | Apparatus for controlling hydraulic circuit of construction equipment |
EP3434910B1 (en) * | 2016-03-22 | 2024-02-28 | Sumitomo (S.H.I.) Construction Machinery Co., Ltd. | Shovel and control valve for shovel |
EP3225583B1 (en) * | 2016-03-31 | 2019-02-13 | Cargotec Research & Development Ireland Limited | A sectional hydraulic valve and a truck mounted forklift incorporating such a valve |
JP6687054B2 (en) * | 2018-03-29 | 2020-04-22 | コベルコ建機株式会社 | Swivel work machine |
JP6992721B2 (en) * | 2018-09-28 | 2022-01-13 | コベルコ建機株式会社 | Hydraulic drive for traveling work machines |
JP7268504B2 (en) | 2019-06-28 | 2023-05-08 | コベルコ建機株式会社 | hydraulic controller |
CN114934559B (en) * | 2022-06-07 | 2023-11-14 | 柳州柳工挖掘机有限公司 | Quick change device disengagement control system, method and engineering machinery |
Family Cites Families (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5083428A (en) * | 1988-06-17 | 1992-01-28 | Kabushiki Kaisha Kobe Seiko Sho | Fluid control system for power shovel |
JPH07116721B2 (en) * | 1989-01-31 | 1995-12-13 | 油谷重工株式会社 | Hydraulic circuit of hydraulic excavator |
JPH07122276B2 (en) * | 1989-07-07 | 1995-12-25 | 油谷重工株式会社 | Hydraulic pump control circuit for construction machinery |
US5063739A (en) * | 1991-02-19 | 1991-11-12 | Caterpillar Inc. | Load sensing hydraulic control system |
WO1993011364A1 (en) * | 1991-11-25 | 1993-06-10 | Kabushiki Kaisha Komatsu Seisakusho | Hydraulic circuit for operating plural actuators and its pressure compensating valve and maximum load pressure detector |
JPH06123302A (en) * | 1992-10-08 | 1994-05-06 | Kayaba Ind Co Ltd | Oil pressure controller of construction machine |
JP3013225B2 (en) * | 1995-01-11 | 2000-02-28 | 新キャタピラー三菱株式会社 | Hanging work control device |
JP3550260B2 (en) * | 1996-09-30 | 2004-08-04 | コベルコ建機株式会社 | Actuator operating characteristic control device |
JP4111286B2 (en) | 1998-06-30 | 2008-07-02 | コベルコ建機株式会社 | Construction machine traveling control method and apparatus |
-
2000
- 2000-04-13 JP JP2000112340A patent/JP3491600B2/en not_active Expired - Fee Related
-
2001
- 2001-04-11 DE DE60120545T patent/DE60120545T2/en not_active Expired - Lifetime
- 2001-04-11 AT AT01109032T patent/ATE330075T1/en not_active IP Right Cessation
- 2001-04-11 EP EP01109032A patent/EP1146175B1/en not_active Expired - Lifetime
- 2001-04-13 US US09/833,625 patent/US6430922B2/en not_active Expired - Fee Related
Cited By (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20140105714A1 (en) * | 2011-05-11 | 2014-04-17 | Volvo Construction Equipment Ab | Hybrid excavator including a fast-stopping apparatus for a hybrid actuator |
US8869924B2 (en) * | 2011-05-11 | 2014-10-28 | Volvo Construction Equipment Ab | Hybrid excavator including a fast-stopping apparatus for a hybrid actuator |
US20140345268A1 (en) * | 2011-12-15 | 2014-11-27 | Volvo Construction Equipment Ab | Travel control system for construction machinery |
CN103375449A (en) * | 2012-04-23 | 2013-10-30 | 住友建机株式会社 | Hydraulic loop for mechanical construction and hydraulic control device thereof |
US9988792B2 (en) | 2013-01-17 | 2018-06-05 | Jiangsu Hengli Highpressure Oil Cylinder Co., Ltd. | Hydraulic apparatus based on confluence control mode |
Also Published As
Publication number | Publication date |
---|---|
EP1146175A1 (en) | 2001-10-17 |
JP3491600B2 (en) | 2004-01-26 |
JP2001295804A (en) | 2001-10-26 |
EP1146175B1 (en) | 2006-06-14 |
DE60120545T2 (en) | 2007-05-31 |
DE60120545D1 (en) | 2006-07-27 |
ATE330075T1 (en) | 2006-07-15 |
US6430922B2 (en) | 2002-08-13 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US6430922B2 (en) | Construction machine | |
EP0795690B1 (en) | Hydraulic driving device | |
US6502499B2 (en) | Hydraulic recovery system for construction machine and construction machine using the same | |
US6244048B1 (en) | Hydraulique drive device | |
KR20060131961A (en) | Hydraulic drive device for working machine | |
JPH10103306A (en) | Actuator operating characteristic controller | |
JP2002031104A (en) | Actuator control device of hydraulic-driven machine | |
KR20130137192A (en) | Boom-swivel compound drive hydraulic control system of construction machine | |
JP2005061477A (en) | Hydraulic driving device | |
US6378302B1 (en) | Hydraulic circuit system | |
JP4240075B2 (en) | Hydraulic control circuit of excavator | |
US20110088785A1 (en) | Safety feature for stuck valve | |
JP2009167618A (en) | Hydraulic circuit of hydraulic excavator | |
JP2003004003A (en) | Hydraulic control circuit of hydraulic shovel | |
US11060261B2 (en) | Slewing hydraulic work machine | |
JP6615137B2 (en) | Hydraulic drive unit for construction machinery | |
JP3450702B2 (en) | Hydraulic circuit of work machine with boom | |
JP3403538B2 (en) | Control equipment for construction machinery | |
JP2003090302A (en) | Hydraulic control circuit of construction machine | |
CN114746612A (en) | Working machine | |
JP2003028101A (en) | Hydraulic control device of construction machine | |
JPH0610376A (en) | Hydraulic circuit for hydraulic-operated construction equipment | |
JP3061529B2 (en) | Hydraulic drive for hydraulic excavator with loader front | |
JP7455285B2 (en) | construction machinery | |
US11885105B2 (en) | Hydraulic control device for work machine |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
AS | Assignment |
Owner name: KOBELCO CONSTRUCTION MACHINERY CO., LTD., JAPAN Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:TOHJI, YUTAKA;REEL/FRAME:012038/0126 Effective date: 20010620 |
|
FEPP | Fee payment procedure |
Free format text: PAYER NUMBER DE-ASSIGNED (ORIGINAL EVENT CODE: RMPN); ENTITY STATUS OF PATENT OWNER: LARGE ENTITY Free format text: PAYOR NUMBER ASSIGNED (ORIGINAL EVENT CODE: ASPN); ENTITY STATUS OF PATENT OWNER: LARGE ENTITY |
|
FPAY | Fee payment |
Year of fee payment: 4 |
|
FPAY | Fee payment |
Year of fee payment: 8 |
|
REMI | Maintenance fee reminder mailed | ||
LAPS | Lapse for failure to pay maintenance fees | ||
STCH | Information on status: patent discontinuation |
Free format text: PATENT EXPIRED DUE TO NONPAYMENT OF MAINTENANCE FEES UNDER 37 CFR 1.362 |
|
FP | Lapsed due to failure to pay maintenance fee |
Effective date: 20140813 |