Classifications

• • E—FIXED CONSTRUCTIONS
  • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
  • E02F—DREDGING; SOIL-SHIFTING
  • E02F9/00—Component parts of dredgers or soil-shifting machines, not restricted to one of the kinds covered by groups E02F3/00 - E02F7/00
  • E02F9/20—Drives; Control devices
  • E02F9/22—Hydraulic or pneumatic drives
  • E02F9/2221—Control of flow rate; Load sensing arrangements
  • E02F9/2225—Control of flow rate; Load sensing arrangements using pressure-compensating valves
  • E02F9/2228—Control of flow rate; Load sensing arrangements using pressure-compensating valves including an electronic controller
• • E—FIXED CONSTRUCTIONS
  • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
  • E02F—DREDGING; SOIL-SHIFTING
  • E02F3/00—Dredgers; Soil-shifting machines
  • E02F3/04—Dredgers; Soil-shifting machines mechanically-driven
  • E02F3/28—Dredgers; Soil-shifting machines mechanically-driven with digging tools mounted on a dipper- or bucket-arm, i.e. there is either one arm or a pair of arms, e.g. dippers, buckets
  • E02F3/36—Component parts
  • E02F3/42—Drives for dippers, buckets, dipper-arms or bucket-arms
  • E02F3/43—Control of dipper or bucket position; Control of sequence of drive operations
  • E02F3/435—Control of dipper or bucket position; Control of sequence of drive operations for dipper-arms, backhoes or the like
• • 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
  • E02F9/2203—Arrangements for controlling the attitude of actuators, e.g. speed, floating function
• • 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
• • E—FIXED CONSTRUCTIONS
  • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
  • E02F—DREDGING; SOIL-SHIFTING
  • E02F9/00—Component parts of dredgers or soil-shifting machines, not restricted to one of the kinds covered by groups E02F3/00 - E02F7/00
  • E02F9/20—Drives; Control devices
  • E02F9/22—Hydraulic or pneumatic drives
  • E02F9/2278—Hydraulic circuits
  • E02F9/2285—Pilot-operated systems
• • 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
  • F15B11/00—Servomotor systems without provision for follow-up action; Circuits therefor
  • F15B11/02—Systems essentially incorporating special features for controlling the speed or actuating force of an output member
  • F15B11/024—Systems essentially incorporating special features for controlling the speed or actuating force of an output member by means of differential connection of the servomotor lines, e.g. regenerative circuits
• • 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
  • F15B11/02—Systems essentially incorporating special features for controlling the speed or actuating force of an output member
  • F15B11/04—Systems essentially incorporating special features for controlling the speed or actuating force of an output member for controlling the speed
  • F15B11/044—Systems essentially incorporating special features for controlling the speed or actuating force of an output member for controlling the speed by means in the return line, i.e. "meter out"
• • 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
  • F15B2211/30525—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
  • F15B2211/31—Directional control characterised by the positions of the valve element
  • F15B2211/3105—Neutral or centre positions
  • F15B2211/3111—Neutral or centre positions the pump port being closed in the centre position, e.g. so-called closed 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
  • F15B2211/3144—Directional 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
  • F15B2211/30—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
  • F15B2211/31588—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 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
  • F15B2211/32—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
• • 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
  • F15B2211/41581—Flow control characterised by the connections of the flow control means in the circuit being connected to an output member and a 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
  • F15B2211/42—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
  • F15B2211/60—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
• • 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
  • F15B2211/6346—Electronic controllers using input signals representing a state of input means, e.g. joystick position
• • 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

Definitions

• the present invention belongs to the technical field of a boom cylinder control circuit in a working machine such as a hydraulic shovel. Background art
• a stick is supported swingably back and forth at a tip end of a boom whose base end is vertically swingably supported by a body of a machine body, and a bucket breaker is attached to a tip end of the stick.
• Some have tools such as clamshells attached.
• the boom 5 is used in addition to the operation of the stick 6. Will be performed simultaneously.
• the boom 5 is moved down and the breaker 8 is pressed against the rock so that an appropriate thrust is always applied to the breaking force 8. Need to work.
• the boom is lowered until the clamshell contacts the object.
• the present invention has been made in view of the above-described circumstances, and has been created with the object of solving these problems, and is directed to a working machine provided with a boom cylinder for vertically moving a boom.
• the control circuit includes a control valve that controls the supply and discharge of pressurized oil to the boom cylinder based on the operation of the operating tool, and the oil in the oil chamber on the head side of the boom cylinder without passing through the control valve. And a control means for controlling the opening and closing of the descending discharge oil passage.
• control circuit of the boom cylinder further includes an ascending-side discharge oil passage for flowing the oil in the boom cylinder opening-side oil chamber to the oil tank without passing through the control valve;
• control means for controlling the opening and closing of the oil passage oil can be discharged from the head-side and mouth-side oil chambers of the boom cylinder when the descending and ascending-side discharge oil passages are opened.
• This means that the boom will move down due to its own weight and move up due to external force, making it easier to operate the boom, for example, when performing work to move the bucket back and forth along the ground surface. It can contribute to reducing fuel consumption.
• the descending-side discharge oil passage is controlled to open based on the operation of the operating tool toward the boom lowering side, while when the descending-side discharge oil passage is open, the operating tool is opened. Even if it is operated to the boom lowering side, from the control valve By controlling the supply of pressurized oil to the boom cylinder, it is possible to prevent the boom from inadvertently lowering under its own weight when the operator does not intend.
• control means for controlling the opening and closing of the descending-side discharge oil passage and the ascending-side discharge oil passage includes an electromagnetic switchable between an open position for opening the discharge oil passage and a closed position for closing the discharge oil passage. It can be configured using a valve.
• FIG. 1 is a side view of a hydraulic excavator.
• FIG. 2 is a hydraulic circuit diagram of the boom cylinder.
• FIG. 3 is a hydraulic circuit diagram of the boom cylinder when the boom lowering side is operated when the “down hold release mode” is set.
• FIG. 4 is a hydraulic circuit diagram of the boom cylinder when the boom cylinder is moved down and down when the “down and up hold release mode” is set.
• Fig. 5 is a diagram showing the work of removing rocks on flat ground using a bucket.
• Fig. 6 is a diagram showing crushing work by a breaker. BEST MODE FOR CARRYING OUT THE INVENTION
• reference numeral 1 denotes a hydraulic excavator.
• the front attachment 4 further comprises a boom 5, which is supported by the upper swing body 3 so as to be vertically swingable, A basic structure such as a stick 6 supported at the tip of the boom 5 so as to be able to swing back and forth, and a bucket 7 attached to the tip of the stick 6 so as to be swingable back and forth. Is as before.
• Various sticks such as a breaker 8 and a clamshell (not shown) are attached to the tip of the stick 6 in place of the bucket 7 in accordance with the work to be performed by the hydraulic excavator 1.
• FIG. 2 shows a hydraulic oil supply / discharge circuit of the boom cylinder 10.
• 11 denotes a hydraulic pump
• 1 2 is an oil tank
• 13 is a control valve for the boom
• the control valve 13 is a first port 13a connected to the hydraulic pump 11 and a second port connected to the oil tank 12.
• 13b boom cylinder 10 mouth side (cylinder reduction side)
• Third port 13c connected to oil chamber 10a, to boom cylinder 10 via logic valve 14 described later 3 side switching valve with 4th port 13d connected to oil chamber 10b, and 3rd port 13e and 13f ports on extension side and reduction side. It is configured.
• the control valve 13 When the pilot pressure is not supplied to both the pilot ports 13 e and 13 f, the control valve 13 is in a neutral position N that closes the first to fourth ports 13 a to 13 d. However, when the pilot pressure is supplied to the expansion side pilot port 13 e, the valve path from the first port 13 a to the fourth port 13 d and the third port 13 c ⁇ Open the valve path to the second port 13b and supply hydraulic oil from the hydraulic pump 11 to the head side oil chamber 10b of the boom cylinder 10 via the logic valve 14 while It is configured to switch to the extension side position X where the oil discharged from the rod-side oil chamber 10a flows into the oil tank 12.
• the valve path from the first port 13 a to the third port 13 c and the second port 13 d to the second Open the valve path to port 13b to supply hydraulic oil from hydraulic pump 11 to rod-side oil chamber 10a of boom cylinder 10 while head-side oil chamber 10b To the contraction side position Y where the oil discharged from the tank flows to the oil tank 12 via the logic valve 14 It is configured.
• 15A and 15B are extension side and reduction side pilot valves, which are operated by moving the operating lever 16 for the boom upward (cylinder extension side) or lowering the boom (cylinder reduction side). ), The pilot pressure is output from the pilot valve 15A or 15B on the operated side.
• the pilot pressure output from the expansion-side pilot valve 15 A is supplied to the expansion-side pilot port 13 e of the control valve 13. Further, the pilot pressure output from the reduction pilot valve 15B is supplied to the reduction pilot port 13f of the control valve 13 via the first solenoid valve 17 described later, and is described later. It is supplied to the pilot port 18a of the control valve 18. Further, when a pilot pressure is output from the reduction pilot valve 15 B, the pressure is detected by the pressure sensor 19.
• the first solenoid valve 17 is a two-position switching valve, which controls the pilot pressure output from the reduction side pilot valve 15 B when the solenoid 17 a is not excited. Although located at the first position X to be supplied to the pilot port 13 f on the valve reduction side, the solenoid 17 a is energized based on a command from the control unit 20 to be described later. It is configured to switch to the second position Y in which the pilot pressure is not supplied to the pilot port 13f.
• the control valve 18 is a two-position switching valve having a pilot port 18a and first to third ports 18b to 18d, and the pilot port 18a is as described above.
• the first port 18b is connected to the first pilot port 14e of the logic valve 14 described later, and the second port 18c is connected to the logic port 15b.
• the second port 14 h of the valve 14 is connected to the oil tank 12, and the third port 18 d is connected to the oil tank 12.
• the control valve 18 supplies pilot pressure to the pilot port 18a. If not, it is located at the first position X, where the valve connecting the first port 18b and the second port 18c is opened and the third port 18d is closed, but the pilot port When the pilot pressure is supplied to 18a, the first port 18b is closed and the valve is switched from the second port 18c to the third port 18d. Is set to
• the logic valve 14 is formed by angling a poppet 14a, and has a first oil chamber 14c having a first port 14b formed therein, a second port 14d and a second port 14d.
• the first port 14 b of the logic valve 14 is connected to the fourth port 13 d of the control valve 13, and the second port 14 d is connected to the head side oil chamber 10 b of the boom cylinder 10.
• the first pilot port 14 e is connected to the first port 18 b of the control valve 18, and the second pilot port 14 h is connected to the second port 18 c of the control valve 18, as described above. Have been.
• the ammunition 14 g is set so as to press the poppet 14 a toward a closed position described later.
• the port 14a closes a valve path '14k for communicating the first oil chamber 14c with the second oil chamber 14' and closes the boom cylinder oil chamber 10b. Closed position (position of port 14a in Fig. 2) to prevent oil from flowing into and out of valve line 14k It is configured to be movable to an open position (the position of the poppet 14a in FIGS. 3 and 4) that allows oil to enter and exit the boom cylinder oil chamber 10b.
• the pressure introduced into the ammunition storage chamber 14i and the pressing force of the ammunition 14g act as a force for pressing the port 14a toward the closed position
• the pressure input to the first oil chamber 14c and the second oil chamber 14f is set to act as a force for pressing the port 14a toward the open position.
• the port 14a presses the pressure A introduced into the ammunition storage chamber 14i and the pressure of the ammunition 14g. Although it is pushed to the closed position by the total pressure (A + B) with the pressure B, the above total pressure (A +
• the control valve 18 when the control valve 18 is located at the first position X, that is, when the operation lever 16 for the boom is not operated on the boom lowering side, the port 14a is operated by the hydraulic pump 1 As long as the pressure oil from 1 is not input to the first oil chamber 14c, it is held in the closed position to prevent the oil from being discharged from the boom cylinder head side oil chamber 10b, while operating the boom.
• the lever 16 When the lever 16 is operated to the boom raising side and the pressure oil from the hydraulic pump 11 is input to the first oil chamber 14c, it is configured to be in the open position.
• the logic valve 14 is located at the open position when the boom operation lever 16 is operated to the lower side or the upper side, and allows the oil to enter and exit the boom cylinder head side oil chamber 10 b. However, when the boom operation lever 16 is not operated on either the lower side or the upper side, the oil is discharged from the boom cylinder head side oil chamber 10 b while being held in the closed position. This prevents the boom 5 from falling due to the weight of the front attachment 4 even if an accident such as leakage occurs in the piping from the control valve 13 to the boom cylinder 10. Can be prevented.
• the logic valve 14 and the control valve 18 are directly mounted on the boom cylinder 10 as one valve unit for preventing the weight from dropping. .
• a descending discharge oil passage E reaching the oil tank 12 is formed in a branched manner.
• the descending oil passage E is provided with a second solenoid valve 21 described later.
• the oil passage connecting the control valve third port 13c and the boom cylinder rod-side oil chamber 10a forms an ascending discharge oil passage F that reaches the oil tank 12.
• a third solenoid valve 22 described below is arranged in the upward discharge oil passage F.
• the second solenoid valve 21 and the third solenoid valve 22 are two-position switching valves.
• the solenoids 21 a and 22 a are not energized, the descending-side discharge oil passage and the rising Although it is located at the closed position X that closes the side discharge oil passage F, the solenoid oil 21 a and 22 a are energized based on a command from the control unit 20, so that the descending discharge oil passage It is configured to switch to the open position Y, which opens the rising oil discharge passage F, respectively.
• the second solenoid valve 21 is located at the open position Y, the oil discharged from the boom cylinder head side oil chamber 10b through the logic valve 14 at the open position is moved downward.
• the third solenoid valve 22 is in the open position Y, the boom cylinder rod-side oil chamber 10 can be supplied to the oil tank 12 via the discharge oil passage E.
• the oil discharged from a It is designed to be able to flow into the oil tank 12.
• control unit 20 is configured using a microcomputer or the like, and receives signals from the pressure sensor 19 and a mode selection switch 23 described later, and A control signal for solenoid excitation is output to the first to third solenoid valves 17, 21, 22 based on a signal.
• the mode selection switch 23 is provided in the driver's seat of the hydraulic excavator 1, and uses a “normal mode” and a breaker 8 for performing a normal operation such as excavation and loading.
• the three modes can be selected and set: ⁇ Descent holding release mode '' when performing crushing work, etc., and ⁇ Descent and lifting holding release mode '' when performing work such as moving the bucket 7 back and forth along the ground.
• the control unit 20 is configured to operate the first, second, and third solenoid valves 17, 21. 2 and 2 are not output as solenoid excitation signals.
• the first solenoid valve 17 is located at the first position X where the pilot pressure output from the reduction side pilot valve 15 B is supplied to the control valve reduction side pilot port 13 ⁇ .
• the second solenoid valve 21 and the third solenoid valve 22 are located at a closed position X that closes the descending-side discharge oil passage F and the ascending-side discharge oil passage F, respectively.
• the pilot pressure is output from the reduction-side pilot valve 15 B.
• the solenoid valve 17 is supplied to the control valve reduction side pilot port 13 f via the solenoid valve 17 to switch the control valve 13 to the reduction side position Y, while being supplied to the control valve 18 pilot port 18 a.
• the pressure oil output from the hydraulic pump 11 is supplied to the boom cylinder rod side oil chamber 10a via the control valve 13 at the reduction side position Y.
• the oil in the boom cylinder head-side oil chamber 1 Ob is discharged to the oil tank 12 via the logic valve 14 at the open position and the control valve 13 at the reduction position Y.
• the cylinder 10 contracts and the boom 5 moves down.
• the controller 20 when the mode selection switch 23 is set to the “lower hold release mode”, the controller 20 outputs a solenoid excitation signal to the first solenoid valve 17.
• the first solenoid valve 17 switches to the second position Y in which the pilot pressure output from the reduction pilot valve 15B is not supplied to the control valve reduction pilot port 13f.
• the control unit 20 outputs a solenoid excitation signal to the second solenoid valve 21 when the pressure sensor 19 detects the output of pilot pressure from the contraction-side pilot valve 15B.
• the second solenoid valve 21 is switched to the open position Y for opening the descending discharge oil passage E.
• the third solenoid valve 2 No solenoid excitation signal is output to 2
• the third solenoid valve 22 is held at the closed position X that closes the ascending-side discharge oil passage F.
• the control valve 13 is located at the neutral position N and the control valve 18 is located at the first position X. In this state, the boom cylinder 10 is stopped and the boom cylinder 10 expands and contracts even when the boom 5 is subjected to a downward or upward external force, as in the case of the “normal mode” described above. It won't.
• the hydraulic oil of the hydraulic pump 11 is moved to the extension side position X as in the “normal mode” described above. Can be supplied to the boom cylinder head side oil chamber 10b via the control valve 13 and the open position logic valve 14.
• the second solenoid valve 21 is located at the closing position X which closes the descending side discharge oil passage E, and the pressure of the hydraulic pump 11 is The oil will not be discharged to the oil tank 1 2 ⁇ 1 via the descending drain oil passage E.
• the oil in the oil chamber 1 ⁇ a on the boom cylinder rod side is discharged to the oil tank 12 via the control valve 13 at the extension side position X, and the boom cylinder 10 is extended and the boom 5 is extended. It is moving up.
• the pilot pressure is output from the reduction side pilot valve 15 B. Is not supplied to the control valve reduction side pilot port 13 f because the first solenoid valve 17 is located at the second position Y, and the control valve 13 is held at the neutral position N.
• the pilot pressure output from the reducing pilot valve 15B is supplied to the pilot port 18a of the control valve 18 to switch the control valve 18 to the second position Y, and Based on the detection of the pilot pressure output by the pressure sensor 19, the control unit 20 outputs a solenoid excitation signal to the second solenoid valve 21. Switch to open position Y to open oil passage E.
• the control valve 13 is located at the neutral position N and the hydraulic oil from the hydraulic pump 11 is supplied to the boom cylinder. Although it is not supplied to the oil tank 10, the oil in the oil chamber 10 b on the cylinder head side is supplied to the oil tank via the logic valve 14 in the open position and the second solenoid valve 21 in the open position Y It is flowing to 1 and 2. Then, in this state, the boom 5 is lowered by its own weight of the front attachment 4 until the tool such as the breaker 8 contacts the obstacle and is controlled to move downward.
• the controller 20 sends the solenoid excitation signal to the first solenoid valve 17 and the third solenoid valve 22. Is output.
• the first solenoid valve 17 switches to the second position Y where the pilot pressure output from the contraction-side pilot valve 15B is not supplied to the control valve reduction-side pilot port 13f.
• the third solenoid valve 22 is switched to the open position Y that opens the ascending oil discharge passage F.
• the control unit 20 outputs a solenoid excitation signal to the second solenoid valve 21.
• the second solenoid valve 21 is switched to the open position Y for opening the descending discharge oil passage E.
• the hydraulic oil of the hydraulic pump 11 moves the control valve 13 at the extension side position X and the control valve 13 at the open position. It is supplied to the boom cylinder head side oil chamber 10 b via the logic valve 14.
• the second solenoid valve 21 is located at the closing position X for closing the descending discharge oil passage E, and the hydraulic pump 1 1 Is not discharged to the oil tank 12 via the descending discharge oil passage E.
• the oil in the boom cylinder head side oil chamber 10a is discharged to the oil tank 12 via the control valve 13 at the extension position X or the third solenoid valve 22 at the open position Y.
• the boom cylinder 10 extends and the boom 5 moves upward.
• the mode selection switch 23 is set to the “normal mode” when performing work such as excavation and loading.
• pressure oil is supplied to the boom cylinder 10 based on the operation of the boom operation lever 16, while the ascending discharge oil passage E and the descending discharge oil passage F are both closed. Therefore, the boom 5 can be vertically moved based on the operation of the boom operation lever 16 without the boom 5 being vertically moved by an external force.
• the mode selection switch 23 is set to the "downward hold release mode".
• the control valve 13 is maintained at the neutral position N, while the discharge oil passage F on the lower side is opened, and the boom 5 is moved to the front attachment. It moves down by its own weight of 4.
• the breaker 8 can be pressed downward by the weight of the front attachment 4 to obtain the thrust required for the crushing work.
• the reaction force can be escaped, and the play force work can be performed efficiently.
• the mode selection switch 23 should be set to the “down and up hold release mode”.
• the control valve 13 is held at the neutral position N, and the ascending discharge oil passage E and the descending discharge oil passage F are opened. Accordingly, the boom 5 moves up due to external force and moves down due to the weight of the front attachment 4.
• the boom 5 automatically moves upward by the reaction force received from the ground by the bucket 7, while the front attachment 4 owns the weight of the bucket 7.
• the boom 5 can be moved down by its own weight or moved up by the external force acting on the boom 5.
• the operation of the boom 5 becomes easier when crushing stones with the breaker 8, removing rocks on flat ground with the bucket 7, or scooping up objects with a clamshell. Performance is improved.
• the lowering of the boom 5 due to its own weight is performed when the mode selection switch 23 is set to the “down hold release mode” or the “down and up hold release mode” and the operation lever 16 for the boom is moved. Since the configuration is permissible only when the operation is performed on the descending side, there is an advantage that a trouble that the boom 5 is inadvertently lowered by its own weight against the operator's intention can be avoided.
• the discharge of oil from the head-side oil chamber of the boom cylinder is allowed when the descending-side discharge oil passage is opened.
• the boom moves down by its own weight, which makes it easier to operate the boom and reduces fuel consumption, for example, when performing crushing work using a breaker. May be available.

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• Engineering & Computer Science (AREA)
• General Engineering & Computer Science (AREA)
• Physics & Mathematics (AREA)
• Fluid Mechanics (AREA)
• Mining & Mineral Resources (AREA)
• Civil Engineering (AREA)
• Structural Engineering (AREA)
• Mechanical Engineering (AREA)
• Operation Control Of Excavators (AREA)
• Fluid-Pressure Circuits (AREA)

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• 2000
  • 2000-03-17 JP JP2000076002A patent/JP3627972B2/ja not_active Expired - Fee Related
  • 2000-09-04 DE DE60040746T patent/DE60040746D1/de not_active Expired - Lifetime
  • 2000-09-04 WO PCT/JP2000/006005 patent/WO2001071110A1/ja active Application Filing
  • 2000-09-04 EP EP00956920A patent/EP1211359B1/de not_active Expired - Lifetime

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