WO2016169938A1 - Circuit hydraulique et engin de chantier - Google Patents

Circuit hydraulique et engin de chantier Download PDF

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Publication number
WO2016169938A1
WO2016169938A1 PCT/EP2016/058679 EP2016058679W WO2016169938A1 WO 2016169938 A1 WO2016169938 A1 WO 2016169938A1 EP 2016058679 W EP2016058679 W EP 2016058679W WO 2016169938 A1 WO2016169938 A1 WO 2016169938A1
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WO
WIPO (PCT)
Prior art keywords
valve
boom
accumulator
hydraulic
channel
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/EP2016/058679
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English (en)
Inventor
Kouji Kishida
Mitsuhiro Toyoda
Yoshihiko Hata
Yuya Kanenawa
Shuhei ORIMOTO
Nobuaki Matoba
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Caterpillar SARL
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Caterpillar SARL
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Filing date
Publication date
Application filed by Caterpillar SARL filed Critical Caterpillar SARL
Publication of WO2016169938A1 publication Critical patent/WO2016169938A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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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
    • E02F9/2278—Hydraulic circuits
    • E02F9/2296—Systems with a variable displacement pump
    • 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
    • E02F9/2292—Systems with two or more pumps

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 first hydraulic cylinder of the plurality of hydraulic cylinders and the accumulator in accordance with an operation amount of the operating device, and accumulates a working fluid, which is ejected from the head of the first hydraulic cylinder, in the accumulator through the first valve; a regenerative circuit that is provided with a second valve for blocking
  • An invention described in claim 2 is a hydraulic circuit wherein the first valve of the hydraulic circuit described in claim 1 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 and an accumulator pressure, and the third valve changes the amount of communication between the first valve and the rod of the first hydraulic cylinder in
  • An invention described in claim 3 is a working machine that has a machine body, a working device mounted in the machine body, and the hydraulic circuit described in claim 1 or 2 that is provided for a plurality of hydraulic cylinders moving the working device up and down.
  • accumulator can be reduced, readily ensuring a necessary pump flow rate with a simple configuration using the first to third valves.
  • 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 and the accumulator pressure
  • the third valve changes the amount of communication between the first valve and the rod of the first hydraulic cylinder in accordance with the operation amount of the operating device and the accumulator pressure. Therefore, the working fluid can effectively be regenerated to the rod of the first hydraulic cylinder while being
  • the invention described in claim 3 can reduce the regeneration flow rate of the pump during the accumulation in the accumulator in order to lower the working device of the working machine, easily ensuring the necessary pump flow rate.
  • 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 is an explanatory diagram schematically showing a control algorithm of a first valve of the circuit.
  • Fig. 4 is an explanatory diagram schematically showing a control algorithm of a second valve of the circuit.
  • Fig. 5 is an explanatory diagram schematically showing a control algorithm of a second valve of the circuit.
  • Fig. 5 is an explanatory diagram schematically showing a control algorithm of a third valve of the circuit.
  • Fig. 6 is an explanatory diagram schematically showing a part of a flow rate control algorithm of a pump of the circuit.
  • Fig. 7 is an explanatory diagram schematically showing a part of a flow rate control algorithm of a pump of the circuit.
  • Fig. 7 is an explanatory diagram schematically showing another part of the flow rate control algorithm of the pump of the circuit .
  • Fig. 8 is an explanatory diagram schematically showing a control algorithm of an engine power assist function of the circuit .
  • Fig. 9 is a perspective view showing a working machine provided with this hydraulic circuit.
  • 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 swash plate angles are controlled by regulators 16, 17, 18 and detected by swash plate angle sensors 16 ⁇ , 17 ⁇ , 18 ⁇ .
  • 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 21, and have the pump discharge pressures thereof detected by pressure sensors 24, 25. 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
  • 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, a regenerative circuit B and an auxiliary regenerative circuit C 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
  • 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
  • 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, 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, and a
  • pilot-operated valves are used as these valves 61 to 63, the pilot-operated valves being switched when the solenoid switching valves are operated by, for example, the operator in the cab 5 (Fig. 9) or the like operating an operating device such as a lever, not shown, to control the supply and discharge of the pilot pressure.
  • the control valves 61 to 63 are shown as solenoid proportional direction control valves in the diagrams.
  • 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.
  • 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, and the channel 76 branches off from the channel 40.
  • the regeneration control valve 63 is a flow rate control valve that regenerates some (approximately half) of the hydraulic oil, which is discharged from the head of the boom cylinder 7cl to the first accumulators 46 through the control valve 61, to the rod of the boom cylinder 7cl, by switching between enabling and blocking the communication between a channel 82 branching off from the upstream side of the check valve 67 with respect to the control valve 61, i.e. the channel 68, and a channel 84 : that extends through a check valve 83 and is connected to the channel 39, i.e., the rod of the boom cylinder 7cl.
  • this regeneration control valve 63 enables the communication between the control valve 61 and the head o the boom cylinder 7cl when accumulating the hydraulic oil in the first accumulators 46 by switching the control valve 61, and blocks the communication between the control valve 61 and the head of the boom cylinder 7cl when blocking the
  • 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 some (approximately half) of the hydraulic 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 hydraulicoil ejected from the head of the boom cylinder 7c2.
  • the auxiliary regenerative circuit C is a circuit branching off from the accumulation circuit A, in which 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, channel 82, regeneration control valve 63, check valve 83, and channel 84 of the boom energy recovery valve 31, and reaches the rod-side end of the boom cylinder 7cl through the channel 39.
  • the auxiliary regenerative circuit C functions to regenerate, to the rod of the boom cylinder 7cl, some of the hydraulic oil ejected from the head of the boom cylinder 7cl, except for some of which to be accumulated in the first accumulators 46.
  • 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 D 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 D to the tank 21 and a makeup function capable of replenishing the motor drive circuit D 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 D 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 ⁇ , 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.
  • the boom control valves 26, 28, the slewing control valve 91, and other hydraulic actuator control valves that are not shown are pilot-operated by a manually operated valve which is a so- called remote-control valve operated by the operator in the cab 5 (Fig. 9) 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. 9) is
  • the hydraulic oil then flows from the channel 82 and is then regenerated to the rod of the boom cylinder 7cl through the regeneration control valve 63 switched to the communication position and through the check valve 83, the channel 84, and the channel 39.
  • the control valve 61 switches 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, and the accumulator pressure of the first accumulators 46 detected by the pressure sensor 55. Specifically, the pilot pressure that is set based on the operation amount of the lever is corrected based on a predetermined table (converter) Tl, and the accumulator pressure is corrected based on a predetermined table
  • 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 THl .
  • the output pressure is set constant. Furthermore, according to the table T2, in the region where the accumulator pressure is equal to or lower than a predetermined threshold TH3, a gain increases with respect to the amount of increase in the accumulator pressure, and in the region where the accumulator pressure exceeds the predetermined threshold TH3, the gain is set constant (e.g., 1) . In this case, the hydraulic oil is prevented by the check valve 78 from returning toward the boom control valve 26.
  • the regeneration control valve 63 switches the amount of communication between the control valve 61 and the rod of the boom cylinder 7cl, in accordance with the operation amount of the lever, i.e., the pilot pressure set based on this operation amount, 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
  • 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.
  • the hydraulic oil passes through the channel 39 and is regenerated to the rod of the boom cylinder 7cl.At this moment, 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.
  • the pilot pressure that is set based on the operation amount of the lever is corrected based on a
  • the table T5 similar to the table Tl shown in Fig. 3 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. 4, and basically the main control valve 62 is switched as soon as the boom lowering operation is detected. Note that 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.
  • 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 hydraulic oil to the rods of the boom cylinders 7cl, 7c2.
  • 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) T6 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) T7 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 TH6.
  • 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 TH7.
  • 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 TH8 and the time where the pilot pressure is equal to or lower than a predetermined threshold TH9 that is greater than the
  • 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 TH10.
  • 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) T10 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) Til to T14 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 THll.
  • a predetermined threshold THll In the region where the accumulator pressure exceeds the predetermined threshold THll, 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 THll but is equal to or lower than a predetermined threshold TH12 that is greater than the predetermined threshold THll, 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 THll.
  • 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 TH14.
  • 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. 9) is performed.
  • the boom energy recovery valve 31 not only switches the control valve 61 and the regeneration control valve 63 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 accumulators 46 that is accumulated through the control valve 61 is egual to or greater than a predetermined 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, 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 TH17, and the flag is switched from 1 to 0 when the
  • predetermined threshold TH18 greater than the predetermined threshold TH17 and a predetermined threshold TH19 greater than the predetermined threshold TH18 are set, the flag is switched from 0 to 1 when the accumulator pressure increases to become equal to or greater than the threshold TH19, and the flag is switched from 1 to 0 when the accumulator pressure decreases to become equal to or lower than the threshold TH18.
  • These tables T15 and T16 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.
  • a first sequence in which the control valve 61 is switched to the communication position and the main control valve 62 is switched to the position for blocking the communication between the heads of the boom cylinders 7cl, 7c2 and enabling the communication between the head of the boom cylinder 7c2 and the rods of the boom cylinders 7cl, 7c2, to form the accumulation circuit A and the regenerative circuit B; a second sequence following the first sequence, in which the hydraulic oil from the control valve 61 is accumulated in the first accumulators 46 and some of the hydraulic oil to be accumulated in the first accumulators 46 is regenerated to the rod of the boom cylinder 7cl by switching the regeneration control valve 63 to the communication position, and then the supply of the hydraulic oil from the main pump 12 to the rod of the boom cylinder 7cl through the boom control valve 26 is increased for a short period of time and thereafter reduced; and a third sequence following the second sequence, in which the
  • regeneration flow rates of the main pumps 12, 13 at the time of the accumulation in the first accumulators 46 can be reduced, and the necessary pump flow rate including the main pump flow rates required by the other hydraulic actuators can easily be ensured with a simple configuration using the control valves 61, 62, 63. Moreover, the size of the main pumps 12, 13 can be reduced.
  • the amount of oil to be regenerated can be sent from the main pump 12, 13 to the other hydraulic actuators, preventing a reduction of the speed of the simultaneous operation and improving the operability of the simultaneous operation.
  • such a configuration can effectively prevent a sudden descent of the boom 7 which is caused when the regeneration flow rates to the rods of the boom cylinders 7cl, 7c2 increases drastically at the time of stroke end of the other actuators .
  • the generated from the boom cylinder 7cl can be increased, resulting in an increase in the energy to be accumulated in the first accumulators 46.
  • the sizes of the components such as the first accumulators 46 and the assist motor 15 can be reduced, resulting in a cost reduction and a simple layout of the circuit.
  • the control valve 61 changes the amount of
  • the regeneration control valve 63 changes the amount of communication between the control valve 61 and the rod of the boom cylinder 7cl in accordance with the operation amount of the lever and the accumulator pressure. Therefore, the hydraulic oil can be accumulated in the first accumulators 46 more adeguately without compromising the operability of the boom lowering operation, and the
  • the flow rate of the hydraulic oil discharged from the main pumps 12, 13 to the rod of the boom cylinder 7cl can be reduced by effectively regenerating the hydraulic oil to the rod of the boom cylinder 7cl, ensuring the necessary pump flow rate more easily.
  • 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.
  • concentrating a load on the boom cylinder 7cl alone can increase the energy to be accumulated in the first accumulators 46. Therefore, substantial assist can be performed with a small accumulator, resulting in a cost reduction and a compact machine body layout.
  • 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)
  • Mining & Mineral Resources (AREA)
  • Civil Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Structural Engineering (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 pendant qu'un fluide hydraulique est accumulé dans un accumulateur avec des structures simples. Un circuit hydraulique comprend un circuit d'accumulation de pression (A) accumulant une huile sous pression provenant d'un côté tête d'un vérin (7c1) dans un accumulateur (46) à l'aide d'une soupape de commande (61) qui change une amplitude de communication entre le côté tête du vérin (7c1) et l'accumulateur (46) en fonction du degré de fonctionnement d'un levier. Le circuit hydraulique comprend un circuit de régénération (B) régénérant l'huile sous pression provenant du côté tête du vérin (7c2) dans les vérins (7c1), (7c2) à l'aide d'une soupape de commande principale (62) qui ferme la communication entre les côtés de tête des vérins (7c1), (7c2) et fait communiquer le côté tête du vérin (7c2) et les côtés de tige respectifs des vérins (7c1), (7c2) lorsque l'huile sous pression est accumulée dans l'accumulateur (46). Le circuit hydraulique comprend un circuit de régénération auxiliaire (C) régénérant une partie de l'huile hydraulique accumulée dans l'accumulateur (46) à l'aide d'une soupape de commande de régénération (63) qui change l'amplitude de communication entre la soupape de commande (61) et un côté tige du vérin (7c1) selon le degré de fonctionnement du levier.
PCT/EP2016/058679 2015-04-21 2016-04-20 Circuit hydraulique et engin de chantier Ceased WO2016169938A1 (fr)

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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

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2010084888A (ja) 2008-10-01 2010-04-15 Caterpillar Japan Ltd 油圧式作業機械の動力回生機構
EP2589823A1 (fr) * 2010-06-30 2013-05-08 Caterpillar SARL Circuit de commande pour restitution d'énergie et engin de travaux
WO2014115645A1 (fr) * 2013-01-28 2014-07-31 キャタピラー エス エー アール エル Dispositif d'assistance de moteur et machine industrielle

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2008089023A (ja) * 2006-09-29 2008-04-17 Kobelco Contstruction Machinery Ltd 油圧アクチュエータの制御装置及びこれを備えた作業機械
US7634911B2 (en) * 2007-06-29 2009-12-22 Caterpillar Inc. Energy recovery system

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2010084888A (ja) 2008-10-01 2010-04-15 Caterpillar Japan Ltd 油圧式作業機械の動力回生機構
EP2589823A1 (fr) * 2010-06-30 2013-05-08 Caterpillar SARL Circuit de commande pour restitution d'énergie et engin de travaux
WO2014115645A1 (fr) * 2013-01-28 2014-07-31 キャタピラー エス エー アール エル Dispositif d'assistance de moteur et machine industrielle

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