JP2005003183A - Hydraulic circuit of construction machinery - Google Patents

Hydraulic circuit of construction machinery Download PDF

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Publication number
JP2005003183A
JP2005003183A JP2003170446A JP2003170446A JP2005003183A JP 2005003183 A JP2005003183 A JP 2005003183A JP 2003170446 A JP2003170446 A JP 2003170446A JP 2003170446 A JP2003170446 A JP 2003170446A JP 2005003183 A JP2005003183 A JP 2005003183A
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JP
Japan
Prior art keywords
accumulator
valve
oil passage
pressure
hydraulic
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.)
Pending
Application number
JP2003170446A
Other languages
Japanese (ja)
Inventor
Hajime Ishikawa
一 石川
Original Assignee
Sumitomo (Shi) Construction Machinery Manufacturing Co Ltd
住友建機製造株式会社
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 Sumitomo (Shi) Construction Machinery Manufacturing Co Ltd, 住友建機製造株式会社 filed Critical Sumitomo (Shi) Construction Machinery Manufacturing Co Ltd
Priority to JP2003170446A priority Critical patent/JP2005003183A/en
Publication of JP2005003183A publication Critical patent/JP2005003183A/en
Pending legal-status Critical Current

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Classifications

    • EFIXED CONSTRUCTIONS
    • E02HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02FDREDGING; SOIL-SHIFTING
    • E02F9/00Component parts of dredgers or soil-shifting machines, not restricted to one of the kinds covered by groups E02F3/00 - E02F7/00
    • E02F9/20Drives; Control devices
    • E02F9/22Hydraulic or pneumatic drives
    • E02F9/2217Hydraulic or pneumatic drives with energy recovery arrangements, e.g. using accumulators, flywheels
    • EFIXED CONSTRUCTIONS
    • E02HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02FDREDGING; SOIL-SHIFTING
    • E02F9/00Component parts of dredgers or soil-shifting machines, not restricted to one of the kinds covered by groups E02F3/00 - E02F7/00
    • E02F9/08Superstructures; Supports for superstructures
    • E02F9/10Supports for movable superstructures mounted on travelling or walking gears or on other superstructures
    • E02F9/12Slewing or traversing gears
    • E02F9/121Turntables, i.e. structure rotatable about 360°
    • E02F9/128Braking systems
    • EFIXED CONSTRUCTIONS
    • E02HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02FDREDGING; SOIL-SHIFTING
    • E02F9/00Component parts of dredgers or soil-shifting machines, not restricted to one of the kinds covered by groups E02F3/00 - E02F7/00
    • E02F9/20Drives; Control devices
    • E02F9/22Hydraulic or pneumatic drives
    • E02F9/226Safety arrangements, e.g. hydraulic driven fans, preventing cavitation, leakage, overheating

Abstract

The load of a hydraulic pump is reduced in a hydraulic circuit of a construction machine.
A branch oil passage is provided in main pipelines connecting a hydraulic motor and a directional control valve, and a pressure is accumulated in an accumulator by interposing a sequence valve in the middle of the branch oil passage. Turn on and off. Furthermore, the accumulator 43 and the port of the directional control valve 11 on the hydraulic pump 10 side are connected by an injection oil passage 46, and a load holding mechanism 50 is provided in the middle of the injection oil passage 46 to store the pressure oil accumulated in the accumulator 43. It can be discharged to the main pipelines 12 and 13.
[Selection] Figure 2

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a hydraulic circuit of a construction machine, and more particularly to energy saving by reducing a load of a hydraulic pump that supplies pressure oil to a hydraulic actuator.
[0002]
[Prior art]
A hydraulic circuit of a conventional construction machine of this type is shown in FIG. The figure shows a hydraulic circuit of a hydraulic motor for turning the upper swing body. Pressure oil discharged from the hydraulic pump 10 is led to one main pipe 12 or 13 via the direction control valve 11, and the hydraulic motor 14. Is rotated and returned to the tank 15 from the other main pipe line 13 or 12 via the direction control valve 11.
[0003]
Relief oil passages 18, 19 having relief valves 16, 17 are branched from the main pipelines 12, 13, and a junction point of the relief oil passages 18, 19 communicates with the tank 15 through an oil passage 20. Further, oil passages 23 and 24 having check valves 21 and 22 branch from the main pipelines 12 and 13, and a junction point of the oil passages 23 and 24 communicates with the tank 15 through the oil passage 20.
[0004]
A brake device 26 is mounted on the output shaft 25 of the hydraulic motor 14, and pressure oil from a pilot pump 29 is always introduced into the brake device 26 via a turning lock valve 28. Therefore, even when the operation lever 27 is in the neutral position, the brake device 26 is kept open, and the switch device (not shown) is operated to switch the turning lock valve 28 by the operator's will, whereby the brake device 26 is operated. 26 braking is possible. When the operation lever 27 is operated to the operation position, pilot pressure is applied from the remote control valve 30 to switch the direction control valve 11, and the hydraulic oil of the hydraulic pump 10 is supplied to the main pipeline 12 or 13, The motor 14 is driven forward or reverse.
[0005]
On the other hand, when the operation lever 27 is returned from the operation position to the neutral position, the directional control valve 11 returns to the neutral position and the main pipelines 12 and 13 are blocked. At this time, since the hydraulic motor 14 tries to continue to rotate due to the inertial force of the upper swing body, the hydraulic pressure of the return side main pipe (for example, 13) rises, and when the hydraulic pressure exceeds a predetermined pressure, the relief valve (for example, 17) Opens, communicates with the supply side main pipe (for example, 12) via the supply side check valve (for example, 21), and the pressure oil circulates to reduce the inertial force of the upper swing body. Part of the pressure oil is discarded into the tank 15 via the oil passage 20.
[0006]
In addition, an inertial body swing back prevention device having a hydraulic circuit similar to this is also known (see, for example, Patent Document 1).
[0007]
[Patent Document 1]
JP-A-6-313402 (pages 1 to 3, FIG. 1).
[0008]
[Problems to be solved by the invention]
In the conventional hydraulic circuit of this type of construction machine, when the operating lever is returned from the operating position to the neutral position, if the hydraulic pressure of the return main line rises above the set pressure of the relief valve, The energy is lost because the part is thrown away into the tank. Further, when the operation lever is fully operated at the start of turning, the load on the hydraulic pump increases and the fuel consumption of the engine increases.
[0009]
Thus, a technical problem to be solved in order to reduce the load on the hydraulic pump occurs in the hydraulic circuit of the construction machine, and the present invention aims to solve this problem.
[0010]
[Means for Solving the Problems]
The present invention has been proposed in order to achieve the above object, and the invention according to claim 1 is a hydraulic circuit of a construction machine for supplying pressure oil from a hydraulic pump to a hydraulic actuator through a directional control valve. A branch oil passage is provided in a main pipeline connecting the hydraulic actuator and the direction control valve to connect an accumulator, and a sequence valve is provided in the middle of the branch oil passage to turn accumulator on and off. A load holding mechanism for connecting the accumulator and a port on the hydraulic pump side of the directional control valve by an injection oil passage, and discharging the pressure oil accumulated in the accumulator to the main pipeline in the middle of the injection oil passage. The hydraulic circuit of the construction machine provided is provided.
[0011]
Therefore, when the sequence valve is turned on, the pressure oil in the main pipeline is accumulated in the accumulator through the branch oil passage. On the other hand, when the load holding mechanism is released, the pressure oil accumulated in the accumulator is discharged to the main line through the direction control valve, thereby reducing the load on the hydraulic pump.
[0012]
According to a second aspect of the present invention, the sequence valve has a check valve that allows a flow in the direction of the accumulator at a normal position, and is configured to be switched to a closed position when the operation lever is operated. Providing a hydraulic circuit.
[0013]
Therefore, the pressure oil from the main pipeline is received by the accumulator, but the pressure oil accumulated in the accumulator is prevented from inadvertently flowing out to the main pipeline.
[0014]
According to a third aspect of the present invention, the load holding mechanism includes a check valve that shuts off the injection oil passage and a switching valve that opens and closes the check valve, and the check mechanism is operated when the operation lever is fully operated. A hydraulic circuit for a construction machine is provided that is configured to open the valve to allow flow from the accumulator in the direction of the directional control valve.
[0015]
Therefore, when the operation lever is fully operated, the load holding mechanism is released, and the pressure oil accumulated in the accumulator is discharged to the main pipeline through the direction control valve.
[0016]
The invention according to claim 4 provides a hydraulic circuit for a construction machine provided with a pressure reducing valve for opening the check valve of the load holding mechanism when the operation lever is fully operated.
[0017]
Therefore, the load holding mechanism can be opened only when the operation lever is fully operated, and the pressure oil accumulated in the accumulator can be released.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 shows a hydraulic excavator 31 as an example of a construction machine, and an upper swing body 34 is mounted on a lower traveling body 32 via a swing mechanism 33 so as to be rotatable. The upper swing body 34 is provided with a cab 35 on one front side thereof, and a boom 36 is attached to the front center portion so as to be able to be raised and lowered. Further, an arm 37 is attached to the tip of the boom 36 so as to be rotatable up and down, and a bucket 38 is attached to the tip of the arm 37.
[0019]
FIG. 2 shows a hydraulic circuit according to the present invention. For convenience of explanation, the same components as those in the prior art are denoted by the same reference numerals and the description thereof is omitted. A branch oil passage 41 is provided in the middle of oil passages 12 and 13 connecting the hydraulic motor 14 and the directional control valve 11 via a shuttle valve 40, and a sequence valve 42 is provided in the middle of the branch oil passage 41 to accumulator. 43 is connected.
[0020]
This sequence valve 42 turns on and off the pressure accumulation in the accumulator 43, and has a check valve 42a that allows the flow in the direction of the accumulator 43 at the normal position. As will be described later, the operation lever 27 is operated to operate the remote control valve. When a pilot pressure equal to or higher than a predetermined pressure is generated from 30 to the pilot oil passage 44 or 45, it is configured to switch to the closing position 42b. That is, the pressure oil accumulated in the accumulator 43 is prevented from flowing into the main pipelines 12 and 13 regardless of whether the sequence valve 42 is switched to the normal position or the closed position.
[0021]
Further, the accumulator 43 and the port on the hydraulic pump 10 side of the direction control valve 11 are connected by an injection oil passage 46, and a load holding mechanism 50 is provided in the middle of the injection oil passage 46. The load holding mechanism 50 is for discharging the pressure oil accumulated in the accumulator 43 to the main pipelines 12 and 13, and for checking and closing the check valve 51 for closing the injection oil passage 46. The check valve 51 is opened when the operation lever 27 is fully operated, and the flow from the accumulator 43 to the direction control valve 11 is allowed. The injection oil passage 46 is provided with a check valve 53 that blocks the flow from the direction control valve 11 toward the load holding mechanism 50.
[0022]
The load holding mechanism 50 will be further described. The check valve 51 includes a poppet 51a for closing or communicating the injection oil passage 46, and a spring chamber 51b for pressing the poppet 51a toward the closing side. Further, the switching valve 52 includes a check valve 52a that blocks the flow in the direction of the tank 15 at a normal position, and a bypass 52b that allows the pressure oil accumulated in the accumulator 43 to communicate with the spring chamber 51b of the check valve 51. When the position is switched to the offset position, the bypass 52b is shut off, and the pressure oil in the spring chamber 51b of the check valve 51 is communicated with the tank 15.
[0023]
Further, a shuttle valve 54 is provided between the pilot oil passages 44 and 45, a pilot oil passage 55 is connected to the outlet of the shuttle valve 54, and a pressure reducing valve 56 is provided in the middle of the pilot oil passage 55. To the pilot port 52c of the switching valve 52. When the operating lever 27 is fully operated, the pilot pressure selected by the shuttle valve 54 is led to the pressure reducing valve 56, and the pilot pressure acts on the pilot port 52c of the switching valve 52 so that the switching valve 52 is in the normal position. To the offset position.
[0024]
Thus, when the operation lever 27 is slowly operated from the neutral position to either the left or right, the pilot pressure is derived from the remote control valve 30 to the pilot oil passage 44 or 45, and the direction control valve 11 is switched, so that the hydraulic pump Ten pressure oils are supplied to the main pipeline 12 or 13, and the hydraulic motor 14 is driven forward or backward.
[0025]
At this time, if the operation lever 27 is not fully operated, the pilot pressure in the pilot oil passage 55 does not reach a predetermined pressure, so that the pressure reducing valve 56 is closed and the switching valve 52 of the load holding mechanism 50 is in the normal position. The check valve 51 is kept closed. Accordingly, the pressure oil accumulated in the accumulator 43 is held in the accumulator 43.
[0026]
On the other hand, when the operation lever 27 is returned from the operation position to the neutral position, the direction control valve 11 returns to the neutral position and the main pipelines 12 and 13 are blocked. At this time, the hydraulic motor 14 tries to continue to rotate due to the inertial force of the upper swing body. However, as in the conventional type, when the hydraulic pressure in the return-side main line (for example, 13) rises and exceeds a predetermined pressure, the relief valve (For example, 17) opens, communicates with the supply side main pipe (for example, 12) through the supply side check valve (for example, 21), and the inertial force of the upper swing body is reduced by circulating pressure oil. In the hydraulic circuit of the present invention, at the same time, the high-pressure oil on the return side passes through the check valve 42a of the shuttle valve 40 and the sequence valve 42 and is accumulated in the accumulator 43. That is, the pressure oil that has been discarded in the conventional tank 15 is accumulated in the accumulator 43.
[0027]
Here, when the operation lever 27 is fully operated, the directional control valve 11 is switched and the pressure oil of the hydraulic pump 10 is supplied to the main pipeline 12 or 13 as in the above-described slow operation, and the hydraulic motor 14 Is driven forward or reverse. Further, the sequence valve 42 is switched to the closed position 42b by the pilot pressure led out from the remote control valve 30 to the pilot oil passage 44 or 45, thereby blocking the branch oil passage 41.
[0028]
Further, the pilot pressure in the pilot oil passage 55 selected at the high pressure by the shuttle valve 54 reaches a predetermined pressure, the pressure reducing valve 56 is opened, and the pilot pressure acts on the pilot port 52 c of the switching valve 52, thereby switching the switching valve 52. Switches from the normal position to the offset position. Accordingly, the pressure oil in the spring chamber 51b of the check valve 51 communicates with the tank 15, and the poppet 51a is pushed toward the spring chamber 51b, thereby opening the check valve 51.
[0029]
Accordingly, the pressure oil accumulated in the accumulator 43 passes through the check valve 51 of the load holding mechanism 50 and is discharged from the injection oil passage 46 to the port on the hydraulic pump 10 side of the direction control valve 11, and from the hydraulic pump 10. A large amount of pressurized oil is supplied to the main pipeline 12 or 13 by joining with the discharged pressurized oil.
[0030]
Thus, for example, even when the operation lever 27 is fully operated at the time of turning start or the like, in addition to the pressure oil discharged from the hydraulic pump 10, the pressure oil accumulated in the accumulator 43 is released. The load on the pump 10 can be reduced and the fuel consumption of the engine can be reduced.
[0031]
It should be noted that the present invention can be variously modified without departing from the spirit of the present invention, and the present invention naturally extends to the modified ones.
[0032]
【The invention's effect】
As described in detail in the above embodiment, the present invention is characterized in that a branch oil passage is provided in a main pipeline connecting a hydraulic actuator and a directional control valve, and an accumulator is connected via a sequence valve. Since the accumulator and the port on the hydraulic pump side of the directional control valve are connected by an injection oil passage, the pressure oil accumulated in the accumulator is discharged to the main pipeline via a load holding mechanism. By accumulating the pressure oil that was previously discarded in the tank in the accumulator, and releasing the pressure oil accumulated in the accumulator when the engine load becomes large, such as when starting turning, by assisting the operation of the hydraulic actuator, The load on the hydraulic pump can be reduced and the fuel consumption of the engine can be suppressed.
[0033]
In the invention according to claim 2, the sequence valve has a normal position having a check valve and a closed position which is switched when the operation lever is operated. Although the pressure oil from the passage is received by the accumulator, the pressure oil accumulated in the accumulator can be prevented from inadvertently flowing out to the main pipeline.
[0034]
Since the load holding mechanism is formed so as to allow the flow from the accumulator to the direction control valve when the operation lever is fully operated, the check valve is opened. In addition to the effect of the invention described in Item 1, when the operation lever is fully operated, the load holding mechanism is opened, and the pressure oil accumulated in the accumulator can be discharged to the main line through the direction control valve.
[0035]
Since the pressure reducing valve for opening the check valve of the load holding mechanism when the operation lever is fully operated is provided in the invention according to the fourth aspect, in addition to the effect of the invention according to the first or third aspect, Only when the lever is fully operated, the load holding mechanism can be opened to release the pressure oil accumulated in the accumulator.
[Brief description of the drawings]
FIG. 1 is a side view of a hydraulic excavator according to an embodiment of the present invention.
FIG. 2 is a hydraulic circuit diagram showing an embodiment of the present invention.
FIG. 3 is a hydraulic circuit diagram showing a conventional technique.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Hydraulic pump 11 Directional control valve 12, 13 Main line 14 Hydraulic motor (hydraulic actuator)
27 Control lever 30 Remote control valve 41 Branch oil passage 42 Sequence valve 43 Accumulator 46 Injection oil passage 50 Load holding mechanism 51 Check valve 52 Switching valve 56 Pressure reducing valve

Claims (4)

  1. In a hydraulic circuit of a construction machine that supplies pressure oil from a hydraulic pump to a hydraulic actuator via a directional control valve,
    A branch oil passage is provided in a main pipeline connecting the hydraulic actuator and the directional control valve to connect an accumulator, and a sequence valve is provided in the middle of the branch oil passage to turn on and off the accumulated pressure in the accumulator. An accumulator and a port on the hydraulic pump side of the directional control valve are connected by an injection oil passage, and a load holding mechanism is provided in the middle of the injection oil passage to discharge the pressure oil accumulated in the accumulator to the main pipeline. A hydraulic circuit of a construction machine characterized by the above.
  2. 2. The hydraulic circuit for a construction machine according to claim 1, wherein the sequence valve has a check valve that allows a flow in an accumulator direction at a normal position, and is configured to switch to a closed position when an operation lever is operated. .
  3. The load holding mechanism has a check valve that shuts off the injection oil passage and a switching valve that opens and closes the check valve. When the operation lever is fully operated, the check valve is opened and the accumulator is operated. The hydraulic circuit for a construction machine according to claim 1, wherein the hydraulic circuit is configured to allow a flow in a direction of the direction control valve.
  4. 4. The hydraulic circuit for a construction machine according to claim 1, further comprising a pressure reducing valve for opening a check valve of the load holding mechanism when the operation lever is fully operated.
JP2003170446A 2003-06-16 2003-06-16 Hydraulic circuit of construction machinery Pending JP2005003183A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
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Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP2003170446A JP2005003183A (en) 2003-06-16 2003-06-16 Hydraulic circuit of construction machinery

Publications (1)

Publication Number Publication Date
JP2005003183A true JP2005003183A (en) 2005-01-06

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Cited By (26)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2008019910A (en) * 2006-07-11 2008-01-31 Shin Caterpillar Mitsubishi Ltd Hydraulic control system of working machine
WO2009024197A1 (en) * 2007-08-23 2009-02-26 Liebherr-France Sas Hydraulic drive, particularly of a digger, particularly for a rotation system
WO2009108830A1 (en) 2008-02-28 2009-09-03 Caterpillar Inc. Control system for recovering swing motor kinetic energy
JP2010234236A (en) * 2009-03-31 2010-10-21 Kubota Corp Crusher
RU2460852C1 (en) * 2011-04-01 2012-09-10 Государственное образовательное учреждение высшего профессионального образования "Южно-Российский государственный технический университет (Новочеркасский политехнический институт)" Pump-accumulator hydraulic drive to rotate earth-mover platform
US8776511B2 (en) 2011-06-28 2014-07-15 Caterpillar Inc. Energy recovery system having accumulator and variable relief
US8850806B2 (en) 2011-06-28 2014-10-07 Caterpillar Inc. Hydraulic control system having swing motor energy recovery
US8919113B2 (en) 2011-06-28 2014-12-30 Caterpillar Inc. Hydraulic control system having energy recovery kit
CN104405004A (en) * 2014-11-07 2015-03-11 徐州徐工挖掘机械有限公司 Rotating overflow energy recycling system of hydraulic excavator
US9068575B2 (en) 2011-06-28 2015-06-30 Caterpillar Inc. Hydraulic control system having swing motor energy recovery
US9086081B2 (en) 2012-08-31 2015-07-21 Caterpillar Inc. Hydraulic control system having swing motor recovery
US9091286B2 (en) 2012-08-31 2015-07-28 Caterpillar Inc. Hydraulic control system having electronic flow limiting
US9139982B2 (en) 2011-06-28 2015-09-22 Caterpillar Inc. Hydraulic control system having swing energy recovery
US9145660B2 (en) 2012-08-31 2015-09-29 Caterpillar Inc. Hydraulic control system having over-pressure protection
US9187878B2 (en) 2012-08-31 2015-11-17 Caterpillar Inc. Hydraulic control system having swing oscillation dampening
US9279236B2 (en) 2012-06-04 2016-03-08 Caterpillar Inc. Electro-hydraulic system for recovering and reusing potential energy
CN105387015A (en) * 2015-12-21 2016-03-09 山河智能装备股份有限公司 Energy-saving hydraulic valve
US9290911B2 (en) 2013-02-19 2016-03-22 Caterpillar Inc. Energy recovery system for hydraulic machine
US9290912B2 (en) 2012-10-31 2016-03-22 Caterpillar Inc. Energy recovery system having integrated boom/swing circuits
US9328744B2 (en) 2012-08-31 2016-05-03 Caterpillar Inc. Hydraulic control system having swing energy recovery
US9388828B2 (en) 2012-08-31 2016-07-12 Caterpillar Inc. Hydraulic control system having swing motor energy recovery
US9388829B2 (en) 2012-08-31 2016-07-12 Caterpillar Inc. Hydraulic control system having swing motor energy recovery
US9932722B2 (en) 2012-10-30 2018-04-03 Sumitomo Heavy Industries, Ltd. Shovel
US10000906B2 (en) 2012-11-09 2018-06-19 Sumitomo Heavy Industries, Ltd. Shovel
US10000910B2 (en) 2012-10-29 2018-06-19 Sumitomo Heavy Industries, Ltd. Shovel
WO2019049436A1 (en) 2017-09-11 2019-03-14 日立建機株式会社 Hydraulic energy recovery apparatus of working machine

Cited By (29)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2008019910A (en) * 2006-07-11 2008-01-31 Shin Caterpillar Mitsubishi Ltd Hydraulic control system of working machine
WO2009024197A1 (en) * 2007-08-23 2009-02-26 Liebherr-France Sas Hydraulic drive, particularly of a digger, particularly for a rotation system
EP2245316A4 (en) * 2008-02-28 2014-01-22 Caterpillar Inc Control system for recovering swing motor kinetic energy
WO2009108830A1 (en) 2008-02-28 2009-09-03 Caterpillar Inc. Control system for recovering swing motor kinetic energy
EP2245316A1 (en) * 2008-02-28 2010-11-03 Caterpillar, Inc. Control system for recovering swing motor kinetic energy
JP2010234236A (en) * 2009-03-31 2010-10-21 Kubota Corp Crusher
RU2460852C1 (en) * 2011-04-01 2012-09-10 Государственное образовательное учреждение высшего профессионального образования "Южно-Российский государственный технический университет (Новочеркасский политехнический институт)" Pump-accumulator hydraulic drive to rotate earth-mover platform
US9068575B2 (en) 2011-06-28 2015-06-30 Caterpillar Inc. Hydraulic control system having swing motor energy recovery
US8776511B2 (en) 2011-06-28 2014-07-15 Caterpillar Inc. Energy recovery system having accumulator and variable relief
US8850806B2 (en) 2011-06-28 2014-10-07 Caterpillar Inc. Hydraulic control system having swing motor energy recovery
US8919113B2 (en) 2011-06-28 2014-12-30 Caterpillar Inc. Hydraulic control system having energy recovery kit
US9139982B2 (en) 2011-06-28 2015-09-22 Caterpillar Inc. Hydraulic control system having swing energy recovery
US9279236B2 (en) 2012-06-04 2016-03-08 Caterpillar Inc. Electro-hydraulic system for recovering and reusing potential energy
US9388828B2 (en) 2012-08-31 2016-07-12 Caterpillar Inc. Hydraulic control system having swing motor energy recovery
US9091286B2 (en) 2012-08-31 2015-07-28 Caterpillar Inc. Hydraulic control system having electronic flow limiting
US9086081B2 (en) 2012-08-31 2015-07-21 Caterpillar Inc. Hydraulic control system having swing motor recovery
US9145660B2 (en) 2012-08-31 2015-09-29 Caterpillar Inc. Hydraulic control system having over-pressure protection
US9187878B2 (en) 2012-08-31 2015-11-17 Caterpillar Inc. Hydraulic control system having swing oscillation dampening
US9388829B2 (en) 2012-08-31 2016-07-12 Caterpillar Inc. Hydraulic control system having swing motor energy recovery
US9328744B2 (en) 2012-08-31 2016-05-03 Caterpillar Inc. Hydraulic control system having swing energy recovery
US10000910B2 (en) 2012-10-29 2018-06-19 Sumitomo Heavy Industries, Ltd. Shovel
US9932722B2 (en) 2012-10-30 2018-04-03 Sumitomo Heavy Industries, Ltd. Shovel
US9290912B2 (en) 2012-10-31 2016-03-22 Caterpillar Inc. Energy recovery system having integrated boom/swing circuits
US10000906B2 (en) 2012-11-09 2018-06-19 Sumitomo Heavy Industries, Ltd. Shovel
US9290911B2 (en) 2013-02-19 2016-03-22 Caterpillar Inc. Energy recovery system for hydraulic machine
CN104405004A (en) * 2014-11-07 2015-03-11 徐州徐工挖掘机械有限公司 Rotating overflow energy recycling system of hydraulic excavator
CN105387015A (en) * 2015-12-21 2016-03-09 山河智能装备股份有限公司 Energy-saving hydraulic valve
WO2019049436A1 (en) 2017-09-11 2019-03-14 日立建機株式会社 Hydraulic energy recovery apparatus of working machine
KR20190113885A (en) 2017-09-11 2019-10-08 히다치 겡키 가부시키 가이샤 Pressure oil energy recovery device of working machine

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