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WO2016169943A1 - Circuit hydraulique et engin de chantier - Google Patents

Circuit hydraulique et engin de chantier Download PDF

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Publication number
WO2016169943A1
WO2016169943A1 PCT/EP2016/058685 EP2016058685W WO2016169943A1 WO 2016169943 A1 WO2016169943 A1 WO 2016169943A1 EP 2016058685 W EP2016058685 W EP 2016058685W WO 2016169943 A1 WO2016169943 A1 WO 2016169943A1
Authority
WO
WIPO (PCT)
Prior art keywords
accumulator
boom
valve
hydraulic
pressure
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.)
Ceased
Application number
PCT/EP2016/058685
Other languages
English (en)
Inventor
Kouji Kishida
Mitsuhiro Toyoda
Yoshihiko Hata
Yuya Kanenawa
Shuhei ORIMOTO
Nobuaki Matoba
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Caterpillar SARL
Original Assignee
Caterpillar SARL
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Caterpillar SARL filed Critical Caterpillar SARL
Publication of WO2016169943A1 publication Critical patent/WO2016169943A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

Links

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
    • E02F9/2217—Hydraulic or pneumatic drives with energy recovery arrangements, e.g. using accumulators, flywheels
    • 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
    • F15B1/00—Installations or systems with accumulators; Supply reservoir or sump assemblies
    • F15B1/02—Installations or systems with accumulators
    • F15B1/024—Installations or systems with accumulators used as a supplementary power source, e.g. to store energy in idle periods to balance pump load
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B21/00—Common features of fluid actuator systems; Fluid-pressure actuator systems or details thereof, not covered by any other group of this subclass
    • F15B21/14—Energy-recuperation means
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/20—Fluid pressure source, e.g. accumulator or variable axial piston pump
    • F15B2211/205—Systems with pumps
    • F15B2211/20507—Type of prime mover
    • 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
    • F15B2211/20507—Type of prime mover
    • F15B2211/20523—Internal combustion engine
    • 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
    • F15B2211/20—Fluid pressure source, e.g. accumulator or variable axial piston pump
    • F15B2211/21—Systems with pressure sources other than pumps, e.g. with a pyrotechnical charge
    • F15B2211/212—Systems with pressure sources other than pumps, e.g. with a pyrotechnical charge the pressure sources being accumulators
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/30—Directional control
    • F15B2211/305—Directional control characterised by the type of valves
    • F15B2211/3056—Assemblies of multiple valves
    • F15B2211/30565—Assemblies of multiple valves having multiple valves for a single output member, e.g. for creating higher valve function by use of multiple valves like two 2/2-valves replacing a 5/3-valve
    • F15B2211/3058—Assemblies of multiple valves having multiple valves for a single output member, e.g. for creating higher valve function by use of multiple valves like two 2/2-valves replacing a 5/3-valve having additional valves for interconnecting the fluid chambers of a double-acting actuator, e.g. for regeneration mode or for floating mode
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/60—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
    • F15B2211/6306—Electronic controllers using input signals representing a pressure
    • F15B2211/6309—Electronic controllers using input signals representing a pressure the pressure being a pressure source supply pressure
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/60—Circuit components or control therefor
    • F15B2211/665—Methods of control using electronic components
    • 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
    • F15B2211/705—Output members, e.g. hydraulic motors or cylinders or control therefor characterised by the type of output members or actuators
    • F15B2211/7051—Linear output members
    • F15B2211/7053—Double-acting 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
    • F15B2211/70—Output members, e.g. hydraulic motors or cylinders or control therefor
    • F15B2211/705—Output members, e.g. hydraulic motors or cylinders or control therefor characterised by the type of output members or actuators
    • F15B2211/7058—Rotary 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
    • F15B2211/70—Output members, e.g. hydraulic motors or cylinders or control therefor
    • F15B2211/71—Multiple output members, e.g. multiple hydraulic motors or cylinders
    • F15B2211/7135—Combinations of output members of different types, e.g. single-acting cylinders with rotary motors
    • 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
    • F15B2211/76—Control of force or torque of the output member
    • F15B2211/761—Control of a negative load, i.e. of a load generating hydraulic energy
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/80—Other types of control related to particular problems or conditions
    • F15B2211/88—Control measures for saving energy

Definitions

  • the present invention relates to a hydraulic circuit provided with an accumulator, and a working machine equipped with the hydraulic circuit.
  • a working machine is configured to accumulate, in an accumulator, pressure oil that is discharged from a boom hydraulic cylinder when lowering the boom, and to also
  • the present invention was contrived in view of these circumstances, and an object thereof is to provide a hydraulic circuit and a working machine that are capable of, with a simpler configuration, ensuring a necessary pump flow rate even when a working fluid is being accumulated in an
  • An invention described in claim 1 is a hydraulic circuit having: a plurality of hydraulic cylinders that simultaneously actuate the same operation by using a working fluid that is pressurized and supplied by a pump in response to an operation of an operating device; an accumulator in which the working fluid is accumulated; an accumulation circuit that is provided with a first valve for changing the amount of communication between a head of a firsthydraulic cylinder of the plurality of hydraulic cylinders and the accumulator, and accumulates a working fluid, which is ejected from the head of the first hydraulic cylinder, in the
  • a regenerative circuit that is provided with a second valve for blocking communication between heads of the plurality of hydraulic cylinders and enabling communication between the head of a second hydraulic cylinder of the plurality of hydraulic cylinders and rods of the first and second hydraulic cylinders when the accumulation circuit accumulates the working fluid in the accumulator, and regenerates a working fluid, which is ejected from the head of the second hydraulic cylinder, to the first and second hydraulic cylinders through the second valve, wherein the first valve changes the amount of communication between the head of the first hydraulic cylinder and the accumulator in accordance with an operation amount of the operating device, a pressure difference between before and after the first valve, and an accumulator pressure.
  • An invention described in claim 2 is a hydraulic circuit wherein the first valve of the hydraulic circuit described in claim 1 relatively reduces the amount of
  • An invention described in claim 3 is a hydraulic circuit according to the hydraulic circuit described in claim 1 or 2, having an assist motor that is connected to the pump and assists with a pump operation by being operated by the accumulated fluid discharged from the accumulator.
  • An invention described in claim 4 is a working machine that has a machine body, a working device mounted in the machine body, and the hydraulic circuit described in any of claims 1 to 3 that is provided for a plurality of hydraulic cylinders moving the working device up and down.
  • the working fluid that is ejected from the head of the first hydraulic cylinder is accumulated in the accumulator through the first valve, and at the same time the working fluid that is ejected from the head of the second hydraulic cylinder is regenerated to the rods of the first and second hydraulic cylinders by means of the second valve. Therefore, the pump flow rate corresponding to the regeneration flow rate can be saved even when the working fluid is accumulated in the accumulator. Consequently, a necessary pump flow rate can easily be ensured with a simple configuration using the first and second valves.
  • the operating speeds of the hydraulic cylinders can be set adequately, because the first valve changes the amount of communication between the head of the first hydraulic cylinder and the accumulator in accordance with the operation amount of the operating device, the pressure difference between before and after the first valve, and the accumulator pressure.
  • the invention described in claim 2 can prevent the operating speeds of the hydraulic cylinders from increasing rapidly when the accumulator pressure is low, i.e., when a load is applied to the hydraulic cylinders or the temperature is low.
  • the load of the engine operating the pump can be reduced through an effective use of the accumulated fluid discharged from the accumulator .
  • the pump flow rate corresponding the regeneration flow rate can be saved even when the accumulation is performed in the
  • the first valve changes the amount of communication between the head of the first hydraulic cylinder and the accumulator in accordance with the operation amount of the operating device, the pressure difference between before and after thefirst valve, and the accumulator pressure, the operating speeds of the hydraulic cylinders can be set
  • Fig. 1 is a circuit diagram showing a way of switching a hydraulic circuit according to an embodiment of the present invention .
  • Fig. 2 is a circuit diagram showing another way of switching the circuit.
  • Fig. 3(a) is an explanatory diagram schematically showing a control algorithm of a first valve of the circuit
  • Fig. 3 (b) an explanatory diagram schematically showing a control algorithm of a second valve of the circuit.
  • Fig. 4 is an explanatory diagram schematically showing a part of a pump flow rate control algorithm of the circuit.
  • Fig. 5 is an explanatory diagram schematically showing another part of the pump flow rate control algorithm of the circuit-.
  • Fig. 6 is an explanatory diagram schematically showing another part of the pump flow rate control algorithm of the circuit-.
  • Fig. 6 is an explanatory diagram schematically showing a control algorithm of an engine power assist function of the circuit .
  • Fig. 7 is an explanatory diagram schematically showing a control algorithm of an engine power assist function of the circuit .
  • Fig. 7 is a perspective view showing a working machine
  • a hydraulic excavator HE which is a working machine, has a machine body 1 that is configured by a lower traveling body 2 and an upper slewing body 3 provided thereon so as to be slewable by a slewing motor 3m, wherein the upper slewing body 3 is equipped with a machine room 4 equipped with the engine, a pump and the like, a cab 5 for protecting an operator, and a working device 6.
  • a base end of a boom 7 that is rotated vertically by two parallel boom cylinders 7cl, 7c2 functioning as hydraulic cylinders is axially supported on the upper slewing body 3
  • a stick 8 that is rotated back and forth by a stick cylinder 8c is axially supported at a tip of the boom 7, and a bucket 9 that is rotated by a bucket
  • cylinder 9c is axially supported at a tip of the stick 8.
  • the two boom cylinders 7cl, 7c2 are provided parallel to the common boom 7 and simultaneously actuate the same operation.
  • ⁇ Fig. 1 shows an engine power assist system that accumulates position energy of the working device 6 in an accumulator through the boom cylinder 7cl, accumulates kinetic energy of the upper slewing body 3 in the accumulator through the slewing motor 3m, and uses these energies to assist engine power .
  • An assist motor 15 is connected to a main pump shaft 14 of main pumps 12, 13 directly or by a gear, the main pumps 12, 13 being driven by a built-in engine 11 of the machine room 4.
  • the main pumps 12, 13 and the assist motor 15 each have a swash plate capable of variably adjusting the
  • the regulators 16, 17, 18 are
  • the regulators 16, 17 of the main pumps 12, 13 can be controlled by a solenoid valve.
  • the regulators 16, 17 of the main pumps 12, 13 can be controlled
  • negative control pressure a negative flow control pressure guided through a negative flow control channel 19nc or with a signal other than the negative control pressure by solenoid switching valves 19a, 19b of a negative flow control valve 19.
  • the main pumps 12, 13 discharge, to channels 22, 23, hydraulic oil which is a working fluid drawn up from a tank
  • Pilot control valves for controlling the directions and flow rates of the hydraulic oil are
  • the pilot control valves include a boom control valve 26 as a main valve for controlling the boom cylinders 7cl, 7c2 and a boom control valve 28 as a sub-valve.
  • An output channel 27 extending from the boom control valve 26 and an output channel 29 extending from the boom control valve 28 are connected to a boom energy recovery valve 31, which is a composite valve, by a channel 30.
  • the boom energy recovery valve 31 is a composite valve that incorporates a plurality of circuit functions in a single block, the plurality of circuit functions being used for switching an accumulation circuit A and a regenerative circuit B shown in Fig. 1, as well as a circuit that guides, to the heads of the two boom cylinders 7cl, 7c2, the hydraulic oil that is pressurized and supplied by the main pumps 12, 13 at the time of a boom lifting operation shown in Fig. 2.
  • a channel 32 extending from a head-side end of the boom cylinder 7cl is connected to the boom energy recovery valve 31 by a channel 34 through a drift reduction valve 33, and a channel 35 extending from a head-side end of the boom cylinder 7c2 is connected to the boom energy recovery valve 31 by a channel 37 through a drift reduction valve 36.
  • An output channel 38 extending from the main boom control valve 26 is connected to the regenerative circuit B of the boom energy recovery valve 31.
  • the rods of the boom cylinders 7cl, 7c2 are connected to the boom energy recovery valve 31 by channels 39, 40.
  • the drift reduction valves 33, 36 control the opening/closing and apertures between the ports by controlling the pilot pressure of a spring chamber by means of pilot valves, not shown.
  • the output channel 27 extending from the main boom control valve 26 can communicate with the output channel 38 by a solenoid switching valve 42 and a check valve 43.
  • the discharge side of the assist motor 15 is connected to the tank 21 by a discharge channel 44.
  • a tank channel 50 extending from an accumulator channel 47 provided with a plurality of first accumulators 46 is connected to the suction side of the assist motor 15 through a relief valve 48 and a check valve 49, and a suction-side channel 52 extending from the accumulator channel 47 is connected to the same through a solenoid switching valve 51.
  • a pressure sensor 55 for detecting pressure accumulated in the first accumulators 46 is connected to the accumulator channel 47.
  • the tank channel 50 extends through a tank channel 56, a spring check valve 57, and an oil cooler 58 or a spring check valve 59 and is connected to the tank 21.
  • the first accumulators 46, the accumulator channel 47, the relief valve 48, the solenoid switching valve 51, and the pressure sensor 55 are
  • the boom energy recovery valve 31 has a control valve 61 that is a first valve configuring a part of the accumulation circuit A and a main control valve 62 that is a second valve functioning as a boom circuit switching valve to configure a part of the regenerative circuit B.
  • Pilot- operated valves are used as the control valve 61 and the main control valve 62, the pilot-operated valves being switched when the solenoid switching valves are operated by, for example, the operator in the cab 5 (Fig. 7) or the like operating an operating device such as a lever, not shown, to control the supply and discharge of the pilot pressure.
  • control valve 61 and the main control valve 62 are shown as solenoid proportional direction control valves in the
  • the control valve 61 is a flow rate control valve that allows the hydraulic oil from the boom cylinder 7cl to be accumulated in the first accumulators 46, by switching between enabling and blocking the communication between the channels 68 and 34 connected to the first accumulators 46 (the
  • the control valve 61 allows the hydraulic oil to flow in an amount larger than the amount of hydraulic oil returned from the normal cylinders (boom cylinders 7cl, 7c2 and the like) to the tank 21, and prioritizes accumulation of pressure oil in the first accumulators 46.
  • Pressure sensors 69, 70 are connected in front of and behind the control valve 61.
  • the main control valve 62 separates the boom
  • the main control valve 62 is configured to block the communication between the heads of the boom cylinders 7cl, 7c2 and enables the communication between the head of the boom cylinder 7c2 and the rods of the boom cylinders 7cl, 7c2 at the time of accumulation in the first accumulators 46 by switching the control valve 61.
  • the channel 30 is connected to the channel 71 through a check valve 78.
  • the channel 72 is connected to the channel 37 and a channel 79 branching off from the channel 30.
  • the channel 73 branches off from the channel 72.
  • the channel 74 is connected to the channel 40 through a check valve 80.
  • the channel 75 is connected to the output channel 38 and the channel 39.
  • the channel 76 branches off from the channel 40.
  • a pressure sensor 81 for detecting the pressure at the head of the boom cylinder 7cl is connected to the channel 75.
  • the accumulation circuit A is a circuit where the hydraulic oil flows from the channel 32 extending from the head-side end of the boom cylinder 7cl, passes through the drift reduction valve 33, the channel 34, the control valve 61 and check valve 67 of the boom energy recovery valve 31, and the channel 68, and reaches the first accumulators 46.
  • the accumulation circuit A functions to accumulate in the first accumulators 46 the oil ejected from the head of the boom cylinder 7cl.
  • the regenerative circuit B is a circuit where the hydraulic oil flows from the channel 35 extending from the head-side end of the boom cylinder 7c2, passes through the drift reduction valve 36, the channel 37, the channel 73, main control valve 62, channel 74, check valve 80, and channel 40 of the boom energy recovery valve 31, reaches the rod-side end of the boom cylinder 7c2, flows again from the channel 35, passes through the drift reduction valve 36, the channel 37, the channel 73, main control valve 62, channel 74, check valve 80, channel 76, main control valve 62, channel 75, and channel 39 in the boom energy recovery valve 31, and then reaches the rod-side end of the boom cylinder 7cl.
  • the regenerative circuit B functions to regenerate, to the rods of the boom cylinders 7cl, 7c2, the oil ejected from the head of the boom cylinder 7c2.
  • Relief valves 94, 95 and check valves 97, 98 that are mutually opposite to each other are provided between channels 92, 93 of a motor drive circuit C that connects a slewing control valve 91 and the slewing motor 3m to each other, the slewing control valve 91 controlling the slewing direction and speed of the slewing motor 3m.
  • a makeup channel 99 which has a tank channel function for returning the oil discharged from the motor drive circuit C to the tank 21 and a makeup function capable of replenishing the motor drive circuit C with hydraulic oil, is connected between the relief valves 94, 95 and between the check valves 97, 98.
  • the makeup channel 99 is connected to a second accumulator 100 that supplies pressure oil. Hydraulic oil is replenished in the channel 92 or 93, whichever is likely to cause a vacuum, from the makeup channel 99 through the check valves 97, 98 at a pressure that does not exceed the spring biasing force of the spring check valve 57.
  • the channels 92, 93 of the motor drive circuit C are made to communicate with a slewing energy recovery channel 104 by check valves 102, 103.
  • This channel 104 is connected to a channel 106 through a sequence valve 105 where the source pressure at the inlet thereof does not change easily due to the back pressure at the outlet of the same.
  • the channel 106 is connected to the first accumulators 46 and the channel 68.
  • the swash plate angle sensors 16 ⁇ j>, 17 ⁇ , 18 ⁇ and the pressure sensors 24, 25, 55 input the detected swash plate angle signals and pressure signals to an in-vehicle controller (not shown) , and the valves 42, 51 are switched by an on/off operation using a drive signal output form the in-vehicle controller (not shown) or a proportional action in accordance with the drive signal.
  • a travel motor control valve such as a travel motor control valve, a stick cylinder control valve, a bucket cylinder control valve and the like
  • a manually operated valve which is a so- called remote-control valve operated by the operator in the cab 5 (Fig. 7) or the like operating the lever or pedal.
  • the pilot valves of the drift reduction valves 33, 36 which are not shown, are also pilot-operated in conjunction with the foregoing valves.
  • FIG. 1 shows a state of the circuit in which a boom lowering operation for lowering the boom 7 (Fig. 7) is
  • the control valve 61 changes the amount of communication between the head of the boom cylinder 7cl and the first accumulators 46, in accordance with the operation amount of the lever, i.e., the pilot pressure set based on this operation amount, the pressure difference between before and after the control valve 61', which is the pressure difference between the head pressure detected by the pressure sensor 69 and acting on the head side of the boom cylinder 7cl and the output pressure of the control valve 61 detected by the pressure sensor 70, and the accumulator pressure of the first accumulators 46 detected by the pressure sensor 55.
  • the pilot pressure that is set based on the operation amount of the lever is corrected based on a predetermined table (converter) Tl
  • the accumulator pressure is corrected based on a predetermined table
  • the amount of increase in the output pressure thereof becomes relatively greater than the amount of increase in the input pressure of the same. Therefore, in the region where the pilot pressure that is set based on the operation amount of the lever exceeds a predetermined threshold THl, the amount of increase in the output pressure with respect to the amount of increase in the input pressure is reduced more compared to when the pilot pressure is equal to or lower than the threshold TH1. Furthermore, in the region where the pilot pressure exceeds a predetermined threshold TH2 that is greater than the predetermined threshold THl, the output pressure is set constant.
  • the gain is set constant (e.g., 1) .
  • the hydraulic oil is prevented by the check valve 78 from returning toward the boom control valve 26.
  • the direction of the hydraulic oil ejected from the head of the boom cylinder 7c2 is controlled to allow the hydraulic oil to flow toward the channel 74 through the channel 35, the drift reduction valve 36, the channel 37, the main control valve 62 of the boom energy recovery valve 31, and the channel 73.
  • the hydraulic oil further passes through the check valve 80 and the channel 40 and is regenerated to the rod of the boom cylinder 7c2.
  • the direction of the hydraulic oil branching off to the channel 76 through the check valve 80 is controlled to allow the hydraulic oil to flow to the channel 75 through the check valve inside the main control valve 62. Consequently, the hydraulic oil passes through the channel 39 and is regenerated to the rod of the boom cylinder 7cl.
  • the operation amount of the main control valve 62 changes in response to the operation amount of the lever, i.e., the pilot pressure that is set based on this operation amount. Specifically, the pilot pressure that is set based on the operation amount of the lever is corrected based on a predetermined table (converter) T3, and the
  • the table T3 similar to the table T2 shown in Fig. 3(a) is used to set the input pressure and the output pressure of the pilot pressure that is set based on the operation amount of the lever, as shown in Fig. 3(b), and basically the main control valve 62 is switched as soon as the boom lowering operation is detected.
  • an excess flow rate of the hydraulic oil ejected from the head of the boom cylinder 7c2 is returned from the boom control valve 26 to the tank 21 after passing through the channel 37, the channel 79, and the channel 30.
  • grounding of the working device 6 Fig.
  • the boom energy recovery valve 31 accumulates the hydraulic oil in the first accumulators 46 at the time of lowering the boom and at the same time regenerates the
  • the pump flow rate from the main pump 12 controlled by the boom control valve 26 to the boom cylinder 7cl is set according to the operation amount of the lever, i.e., the pilot pressure that is set based on this operation amount, and the accumulator pressure of the first accumulators 46.
  • a base flow rate of this pump flow rate is set as follows.
  • the minimum value of a flow rate that is set based on a predetermined table (converter) T4 in accordance with the pilot pressure set based on the operation amount of the lever is compared with the minimum value of a flow rate that is set based on a predetermined table (converter) T5 in accordance with a predetermined short time period at the start of the boom lowering operation that is measured by a time counter TC, such as a lapse of 10 ms .
  • a time counter TC such as a lapse of 10 ms
  • the flow rate decreases in proportion to an increase in the pilot pressure.
  • the flow rate is set constant in the region where the pilot pressure exceeds the predetermined threshold TH5.
  • the flow rate increases as time measured by the time counter TC passes, and the flow rate is set constant from the time where the pilot pressure exceeds a predetermined threshold TH6.
  • the flow rate increases as time measured by the time counter TC passes, and then the flow rate is set constant between the time where the pilot pressure exceeds a predetermined threshold TH7 and the time where the pilot pressure is equal to or lower than a predetermined threshold TH8 that is greater than the
  • predetermined threshold TH7 From the time where the pilot pressure exceeds the predetermined threshold TH8, the flow rate decreases as time passes.
  • the gain increases in proportion to an increase in the pilot pressure, and the gain is set constant (e.g., 1) in the region where the pilot pressure exceeds a predetermined threshold TH9.
  • a flow rate that is obtained by integrating the base flow rate described above with a gain that is set based on the predetermined table (converter) T8 in accordance with the accumulator pressure is set as the foregoing pump flow rate for the boom lowering operation alone.
  • a lever operation such as a stick-in operation, a stick-out operation, a bucket-in operation, or a bucket-out operation is performed simultaneously with the boom lowering operation
  • flow rates that are set based on predetermined tables (converters) T9 to T12 in accordance with the pilot pressures set based on these operations are added up.
  • the gain is set constant (e.g., 1) when the
  • accumulator pressure is equal to or lower than a predetermined threshold TH10.
  • a predetermined threshold TH10 In the region where the accumulator pressure exceeds the predetermined threshold TH10, when the accumulator pressure is relatively small, the amount of increase in the gain is relatively greater than the amount of increase in the accumulator pressure. In the region where the accumulator pressure exceeds the predetermined threshold TH10 but is equal to or lower than a predetermined threshold THll that is greater than the predetermined threshold TH10, the amount of increase in the gain with respect to the amount of increase in the accumulator pressure is reduced more compared to when the accumulator pressure is equal to or lower than the threshold TH10.
  • the gain is set constant (greater than 1) .
  • the amount of increase in the flow rate is relatively greater than the amount of increase in the pilot pressure
  • the amount of increase in the flow rate with respect to the amount of increase in the pilot pressure is reduced more compared to when the pilot pressure is equal to or lower than the threshold TH13.
  • the flow rate is set constant.
  • FIG. 2 shows a state of the circuit in which the boom lifting operation for raising the boom 7 (Fig. 7) is performed.
  • the boom energy recovery valve 31 not only switches the control valve 61 to the blocking position but also switches the main control valve 62 to stop the accumulation of the hydraulic oil in the first accumulators 46 and the regeneration of the same to the rods of the boom cylinders 7cl, 7c2.
  • the boom energy recovery valve 31 also guides the hydraulic oil, which is supplied from the main pumps 12, 13 to the channel 30 through the boom control valves 26, 28, from the channel 79 to the head of the boom cylinder 7c2 through the channel 37, the drift reduction valve 36, and the channel 35, and further guides the hydraulic oil from the check valve 78 to the head of the boom cylinder 7cl through the channel 34, the drift reduction valve 33, and the channel 32.
  • the hydraulic oil ejected from the rod of the boom cylinder 7cl is returned to the tank 21 from the channel 39 and the output channel 38 through the boom control valve 26.
  • the direction of the hydraulic oil ejected from the rod of the boom cylinder 7c2 is controlled to allow the hydraulic oil to flow to the channel 75 through the channel 40, the channel 76, and the main control valve 62, thereby returning the hydraulic oil to the tank 21 from the output channel 38 through the boom control valve 26.
  • engine power assist can be performed in which the assist motor 15 with a motor function, which is coupled to the main pump shaft 14 directly or by a gear, is caused to
  • the engine power assist is performed when the pressure sensor 55 detects that the accumulator pressure of the first
  • the engine power assist is performed when the pressure sensor 55 detects that the accumulator pressure of the first accumulators 46 is equal to or greater than a predetermined second threshold different from the predetermined first threshold.
  • the solenoid switching valve 51 is switched to the communication position in response to the flag, and the assist motor 15 is rotated by the energy accumulated in the first accumulators 46, to assist the hydraulic outputs of the main pumps 12, 13 and reduce the engine load.
  • the engine power assist is not performed using the assist motor 15.
  • this assist flag is ON or in other words 1, the solenoid switching valve 51 is switched to the communication position.
  • the solenoid switching valve 51 When the assist flag is OFF or in other words 0, the solenoid switching valve 51 is switched to the blocking position.
  • the flag is switched from 0 to 1 when the accumulator pressure increases to become equal to or greater than the threshold TH16, and the flag is switched from 1 to 0 when the
  • predetermined threshold TH17 greater than the predetermined threshold TH16 and a predetermined threshold TH18 greater than the predetermined threshold TH17 are set, the flag is switched from 0 to 1 when the accumulator pressure increases to become equal to or greater than the threshold TH18, and the flag is switched from 1 to 0 when the accumulator pressure decreases to become equal to or lower than the threshold TH17.
  • These tables T13 and T14 therefore, each have so-called hysteresis in which the thresholds vary depending on the increase and decrease of the accumulator pressure.
  • the engine power assist function ⁇ reduces , by using the assist motor 15, the load of the built-in engine 11 that is coupled thereto by the main pump shaft 14.
  • control valve 61 changes the amount of communication between the head of the boom cylinder 7cl and the first accumulators 46 in accordance with the operation amount of the lever, the pressure difference between before and after the control valve 61, and the accumulator pressure of the first accumulators 46. Therefore, the hydraulic oil can be accumulated in the first accumulators 46 more
  • the operating speeds of the boom cylinders 7cl, 7c2 can be set adequately. Specifically, because the table Tl (Fig. 3(a)) is set in which when the operation amount of the lever is
  • the control valve 61 relatively lowers the amount of communication between the head of the boom cylinder 7cl and the first accumulators 46, at least either when the pressure difference between before and after the control valve 61 is large or when the accumulator pressure is lower than a predetermined
  • the operating speeds of the boom cylinders 7cl, 7c2 can be set adequately so that the operating speeds of the boom cylinders 7cl, 7c2 do not accelerate drastically at the start, preventing a sudden drop of the working device 6 (Fig. 7) .
  • the cylinders 7cl, 7c2 are operated in conjunction with the other hydraulic actuators (the slewing motor 3m, the stick cylinder 8c, the bucket cylinder 9c, and the like) , the hydraulic oil ejected from the head of the boom cylinder 7c2 is regenerated to the rods of the boom cylinders 7cl, 7c2. Therefore, the oil to be regenerated can be fed from the main pump 12, 13 to the other hydraulic actuators, preventing a reduction of the speed of the simultaneous operation and improving the
  • boom energy recovery valve 31 configured by integrating the plurality of circuit functions into a single block, not only is it possible to obtain a simple layout, but also a cost reduction can be achieved by reducing the number of assembly steps.
  • the present invention is industrially applicable to all businesses that are concerned in manufacturing and sales of hydraulic circuits or working machines.

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  • 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)
  • Chemical & Material Sciences (AREA)
  • Analytical Chemistry (AREA)
  • Fluid-Pressure Circuits (AREA)
  • Operation Control Of Excavators (AREA)

Abstract

L'invention concerne un circuit hydraulique et un engin de chantier pouvant assurer un débit de pompe nécessaire tandis qu'un fluide hydraulique est accumulé dans un accumulateur avec des structures simples, et pouvant régler de manière appropriée une vitesse de fonctionnement d'un vérin hydraulique. De l'huile hydraulique poussée hors d'un côté tête d'un vérin de flèche (7c1) est accumulée dans un premier accumulateur (46) à travers une soupape de commande (61) qui change une amplitude de communication entre le côté tête du vérin de flèche (7c1) et le premier accumulateur (46) en fonction du degré de fonctionnement d'un levier, d'une différence de pression avant et arrière de la soupape de commande (61), et d'une pression d'accumulateur. L'huile hydraulique poussée hors du côté tête du vérin de flèche (7c2) est régénérée dans les vérins de flèche (7c1), (7c2) à l'aide d'une soupape de commande principale (62) qui ferme la communication entre les côtés de tête des vérins de flèche (7c1), (7c2) et fait communiquer le côté tête du vérin de flèche (7c2) et les côtés de tige respectifs des vérins de flèche (7c1), (7c2) lorsque l'huile hydraulique est accumulée dans le premier accumulateur (46).
PCT/EP2016/058685 2015-04-21 2016-04-20 Circuit hydraulique et engin de chantier Ceased WO2016169943A1 (fr)

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JP2015-086577 2015-04-21
JP2015086577A JP6532081B2 (ja) 2015-04-21 2015-04-21 流体圧回路および作業機械

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CN108894274A (zh) * 2018-07-27 2018-11-27 徐州工业职业技术学院 一种挖掘机回转能量回收和再利用系统
CN109563862A (zh) * 2017-03-14 2019-04-02 日立建机株式会社 作业机械的液压驱动装置
CN113677857A (zh) * 2019-04-05 2021-11-19 沃尔沃建筑设备公司 液压机械
EP3951099A4 (fr) * 2019-04-05 2022-11-30 Volvo Construction Equipment AB Machine hydraulique
US20240167488A1 (en) * 2021-03-31 2024-05-23 Eagle Industry Co., Ltd. Fluid circuit
US12281663B2 (en) 2021-03-31 2025-04-22 Eagle Industry Co., Ltd. Fluid circuit
US12292060B2 (en) 2021-03-31 2025-05-06 Eagle Industry Co., Ltd. Fluid circuit
US12435738B2 (en) 2021-09-21 2025-10-07 Eagle Industry Co., Ltd. Fluid circuit

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JP6493916B2 (ja) * 2015-04-21 2019-04-03 キャタピラー エス エー アール エル 流体圧回路および作業機械
CN108915009B (zh) * 2018-07-09 2021-04-16 德润液压科技（常州）有限公司 一种挖掘机回转液压系统
KR102798657B1 (ko) 2021-03-24 2025-04-23 히다치 겡키 가부시키 가이샤 작업 기계

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Cited By (13)

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Publication number Priority date Publication date Assignee Title
CN109563862A (zh) * 2017-03-14 2019-04-02 日立建机株式会社 作业机械的液压驱动装置
CN109563862B (zh) * 2017-03-14 2020-06-19 日立建机株式会社 作业机械的液压驱动装置
CN108894274A (zh) * 2018-07-27 2018-11-27 徐州工业职业技术学院 一种挖掘机回转能量回收和再利用系统
CN108894274B (zh) * 2018-07-27 2020-10-16 徐州工业职业技术学院 一种挖掘机回转能量回收和再利用系统
CN113677857B (zh) * 2019-04-05 2023-05-02 沃尔沃建筑设备公司 液压机械
EP3951099A4 (fr) * 2019-04-05 2022-11-30 Volvo Construction Equipment AB Machine hydraulique
CN113677857A (zh) * 2019-04-05 2021-11-19 沃尔沃建筑设备公司 液压机械
US11802390B2 (en) 2019-04-05 2023-10-31 Volvo Construction Equipment Ab Hydraulic machinery
US11892014B2 (en) 2019-04-05 2024-02-06 Volvo Construction Equipment Ab Hydraulic machine
US20240167488A1 (en) * 2021-03-31 2024-05-23 Eagle Industry Co., Ltd. Fluid circuit
US12281663B2 (en) 2021-03-31 2025-04-22 Eagle Industry Co., Ltd. Fluid circuit
US12292060B2 (en) 2021-03-31 2025-05-06 Eagle Industry Co., Ltd. Fluid circuit
US12435738B2 (en) 2021-09-21 2025-10-07 Eagle Industry Co., Ltd. Fluid circuit

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