KR101155785B1 - Hybrid system of an excavator - Google Patents

Hybrid system of an excavator Download PDF

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Publication number
KR101155785B1
KR101155785B1 KR1020040117896A KR20040117896A KR101155785B1 KR 101155785 B1 KR101155785 B1 KR 101155785B1 KR 1020040117896 A KR1020040117896 A KR 1020040117896A KR 20040117896 A KR20040117896 A KR 20040117896A KR 101155785 B1 KR101155785 B1 KR 101155785B1
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South Korea
Prior art keywords
hydraulic
motor
excavator
pressure
valve
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KR1020040117896A
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Korean (ko)
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KR20060078300A (en
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강병일
장달식
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두산인프라코어 주식회사
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Abstract

The present invention relates to a hybrid device of an excavator, wherein a hydraulic line for supplying discharge pressure of a main hydraulic pump connected to an engine and a motor-generator is pivoted with a front work device consisting of an boom, an arm and a bucket of an excavator through three electronic control valves. Parallelly connected to the mechanism and the traveling mechanism, an electronically controlled ballast valve is installed in the hydraulic line connected to the front work device, the swing hydraulic motor and the traveling motor, and controlled by a controller, while the hydraulic pressure is returned to the return line of the boom cylinder. The motor and the motor-generator are installed, and the accumulator is installed in one hydraulic line of the turning hydraulic motor. In the present invention, the actuator is controlled through a distributed control valve to secure a central space, and by controlling the flow of pressure oil flowing through each actuator using an electronically controlled valve regulator, the speed can be controlled regardless of the load. The high pressure surplus pressure returned from the turning device stores the accumulator to recover the energy, and the hydraulic motor and the motor are operated by the pressure oil recovered from the boom cylinder and converted into electrical energy. By doing so, it is possible to reduce the energy loss of the excavator and to improve fuel efficiency.
Figure R1020040117896
Hybrid devices of excavators, electronically controlled ballast valves, motor-generators

Description

Hybrid hydraulic control system of excavator

1 is a schematic circuit diagram of a hybrid system of an excavator according to the present invention.

※ Explanation of Codes on Major Parts of Drawings

2: main hydraulic pump 3: battery

4: engine 5: auxiliary pump

6: first motor-generator 7: controller

8a, 8b, 8c, 13: Hydraulic lines 9a-9d: Electro-proportional relief valve

10,11,12: solenoid valve 15: bucket cylinder

16: arm cylinder 17: boom cylinder

17a: piston head side chamber 20: front work device

21,25,18: Hydraulic line 26: Traveling device

26a, 26b: driving motor 27, 36: return line

28: hydraulic pump motor 28a: second motor-generator

30: swing device 30a: swing hydraulic motor

33: electromagnetic proportional relief valve 34: pressure reducing valve                 

35: accumulator 37: sequence valve

40: Travel speed selector valve

The present invention relates to a hydraulic control system of an excavator, and in particular, it is easy to control each operating part of the excavator, and also to recover the energy from the high-pressure pressure oil returned when the operating mechanism is operated to improve the engine fuel efficiency of the excavator. And a hybrid hydraulic control system of an excavator that can reduce the amount of soot emissions.

In the conventional general excavator, although a hydraulic control system having excellent operability is configured, there is a disadvantage in that power loss is large because it uses a single spool to control the flow of pressure oil.

Therefore, in order to realize a significant reduction in fuel consumption in an excavator, it is necessary to develop a power transmission system that can operate with higher efficiency than a conventional hydraulic system and to recycle lost energy.

In order to meet these requirements, the existing centralized main control valve was changed to distributed and a hybrid system and a system capable of recycling lost energy were implemented using a method called electronic.

On the other hand, there is a U.S. Patent No. 6,708.787 of Komatsu, Japan, in order to meet the demand as described above, the apparatus according to the invention constitutes a hybrid system, in which one variable pump is controlled by an electronic regulator Consists of.

In addition, the excavator according to the present invention converts and stores the horsepower of the engine to electrical energy, while driving the hydraulic motor to generate power by using the pressure oil returning when the boom is lowered to save the power, the motor at the time of turning stop When it develops, it also stores this energy.

However, the system according to Komatsu's U.S. patent relies on electric motors for rotational driving, making it difficult to secure a space for accommodating the electric motors when compared to a hydraulic motor having a powder density of 20: 1, and damping the hydraulic system. The effect is not available and shock is expected.

In addition, the system according to the US patent uses a general centralized hydraulic control valve can cause a large pressure loss during meter out control, which is the main cause of pressure loss, and also a centralized control valve In this case, it is difficult to secure a central space for installing components such as a battery and an electric motor required by a hybrid system.

Accordingly, the present invention solves various problems occurring in the hybrid system applied to the conventional excavator as described above to secure a central space for installing the hybrid system, and to control the system and recover the lost energy. The purpose of the present invention is to provide an excavator hydraulic control system that can improve the fuel efficiency of the excavator and protect the environment.

Hydraulic control system of the present invention for achieving the above object is a hydraulic boom for supplying the discharge pressure oil of the main hydraulic pump which is connected in parallel to the engine and the generator / motor, the boom of the excavator through three electronic control valves, The front work device consisting of the arm and the bucket is connected in parallel with the swing mechanism and the traveling mechanism, and an electronically controlled ballast valve is installed in the hydraulic line connected to the boom cylinder, the arm cylinder, the bucket cylinder, the swing hydraulic motor and the travel motor. While being controlled by, the hydraulic motor and the motor-generator is installed in the return line of the boom cylinder, and the accumulator is installed in one hydraulic line of the swing hydraulic motor.

The apparatus of the present invention having such a structure is to control each actuator of the excavator through a distributed control valve to ensure a central space, and to control the flow of the hydraulic oil flowing through each actuator using an electronically controlled valve ballast valve It can control the speed irrespective of the speed, and it is easy to control. The pressure is recovered from the head of the boom cylinder by recovering energy by accumulating the pressure oil supplied to the turning device and the high pressure oil returning. By operating the oil passage hydraulic motor and the motor motor and converting them to electric air to recover them, the lost energy of the excavator can be recovered and fuel economy can be improved.

Hereinafter, with reference to the accompanying drawings, the present invention will be described in detail.

1 is a hydraulic circuit diagram showing a configuration of an hydraulic control system of an excavator according to the present invention. As shown in FIG. 1, the hydraulic control system of an excavator according to the present invention includes an engine 4 and an engine 4. It includes a main hydraulic pump (2) and the auxiliary pump (5) driven together by. And on the drive shaft connecting the engine 4 and the main hydraulic pump 2, when the required power of the main hydraulic pump 2 is lower than the output at the optimum efficiency point of the engine 4, the spare power of the engine 4 A first motor-motor 6 for generating electric power is connected, and the first motor-motor 6 is connected with a battery 3 to store electricity generated by the first motor-motor 6.

In addition, the main hydraulic pump 2 includes a turning device 30 including a front working device 20 composed of a bucket cylinder 15, an arm cylinder 16, and a boom cylinder 17, and a turning hydraulic motor 30a. ) And the traveling device 26 including the traveling motors 26a and 26b are connected in parallel through the respective hydraulic lines 8a, 8b and 8c, and to each of the hydraulic lines 8a, 8b and 8c. Open / close valves (10, 11, 12) are connected to selectively supply the hydraulic oil of the main hydraulic pump (2) to each device (20, 26, 30),

The left and right driving motors 26a and 26b of the traveling device 26 are provided with transmissions 26c and 26d for increasing the traveling speed by receiving the hydraulic oil of the auxiliary pump 5 through the hydraulic line 13. 13, a traveling speed selection valve 40 for selecting the traveling speed is provided. Accordingly, the traveling motors 26a and 26b operate by receiving the hydraulic oil from the main hydraulic pump 2 and open and close the traveling speed selection valve 40 according to the control signal of the controller 7. The shift signal pressure is transmitted or interrupted at 26d), and the running speed is increased or decreased.

On the other hand, the bucket cylinder 15, the arm cylinder 16, the boom cylinder 17 of the front work device 20, the turning hydraulic motor 30a of the turning device 30, the traveling motor of the traveling device 26 The hydraulic lines 21, 25, 8b and 8c for supplying the hydraulic oil of the main hydraulic pump 2 to the 26a and 26b respectively control the flow rates supplied through these hydraulic lines 21, 25, 8b and 8c. Electronically controlled ballast valves 22, 23, 24, 32, 38, and 39 are connected, and the electronically controlled ballast valves 22, 23, 24, 32, 38, and 39 are electrically supplied from the controller 7. Each is controlled individually by a control signal.

In addition, the feedback line connecting the bucket cylinder 15, the arm cylinder 16, the boom cylinder 17, and the tank T is controlled by a control signal of the controller 7 to control each relief pressure. Control relief valves 9a, 9b and 9c are provided.

On the other hand, the boom cylinder 17 to which the flow rate of the relatively large number of the main hydraulic pump 2 is supplied or discharged in the front work device 20 in the piston head side chamber 17a of the boom cylinder 17 in the return line ( A hydraulic pump motor 28 is installed in the return line discharged to the tank along 27), and a second motor-generator 28a is mechanically connected to the hydraulic pump motor 28. Accordingly, when the boom is lowered (when the boom cylinder is contracted), the hydraulic pump motor 28 is operated as a motor to drive the second motor-generator 28a with this rotational force to store the generated power in the battery. On the other hand, when the boom is raised at a lower speed than the command, the hydraulic pump motor 28 is operated by the pump and the rotational force is generated by the second motor-generator 28a utilizing the power of the battery.

When the excavator of the present invention having such a structure is operated, driving of the engine 4 is started, and when the required power of the main hydraulic pump 2 is less than the output at the optimum efficiency point of the engine 4, the controller 7 The first motor-generator 6 operates to convert the surplus power of the engine 4 into electric power, and then accumulates in the battery 3.

When there is no work command for the front work device in the controller 7, that is, when the controller 7 does not output an electrical signal to the electromagnetic open / close valve 10 on the front work device 20, the main hydraulic pump ( The flow rate discharged from 2) is no longer transmitted to the front work device 20, and according to the command of the controller 7, the electromagnetic proportional relief valve 9d is opened and recovered to the tank T in a no-load state.

On the other hand, when the front work device 20 consisting of the boom, the arm and the bucket of the excavator receives a work command by the controller 7, the electromagnetic opening and closing valve 10 is opened to pressurize the hydraulic oil of the main hydraulic pump 2 to the front work device. And the flow rate supplied to each hydraulic cylinder (15, 16, 17) of the front work device is connected to each hydraulic line (21, 25, 18). 24), the operation direction control of each hydraulic cylinder (15, 16, 17) is determined by selectively opening and closing the electromagnetic opening and closing valve (n1-n10) installed in each hydraulic line (21, 25, 26) Lose.

When the boom lever installed in the driver's seat is operated to operate the boom of the excavator, the electronically controlled valve valve valve 24 installed in the hydraulic line 18 is opened to control and supply pressure oil toward the boom cylinder 17. The weight is heavy and bulky. In order to operate a large boom, a large amount of pressure oil is required because two boom cylinders 17 are usually installed and used.

In order to satisfy the requirements of the boom cylinder 17, an electronically controlled valve ballast valve 24 is installed in the hydraulic line 18 of the boom, and the hydraulic line 18 and the return line 27 are connected to the electromagnetic open / close valve ( n10).

A hydraulic pump motor 28 is installed between the head side chamber 17a of the boom cylinder 17 and the return line 27. The hydraulic pump motor 28 is mechanically equipped with a second motor generator 28a. Connected. When the boom is lowered, the hydraulic pump motor 28 is operated as a motor to drive the second motor-generator 28a by this rotational force to store the generated power in the battery. On the other hand, when the ascending speed of the boom cylinder 17 is lower than the command value, the hydraulic pump motor 28 is operated by the pump, at which time the motor 28, the second motor-generator 28a utilizes the power of the battery Driven by the generated power.

On the other hand, when a signal for turning the upper swing body is output from the controller 7, the electromagnetic opening and closing valve 11 of the hydraulic line 8b connected to the main hydraulic pump 2 is opened to supply the hydraulic oil to the swinging device 30. The flow rate is controlled by the electronically controlled valverter valve 32 provided in the hydraulic line 8b of the turning device 30.

The turning hydraulic motor 30a of the turning device 30 has a turning direction determined by four electromagnetic open / close valves n11-n14 connected in parallel, and the upper turning direction of the turning hydraulic motor operating lever of the controller 7 as neutral. When the sieve is stopped, the turning hydraulic motor 30a is temporarily rotated by the inertia of the upper swinging body (not shown) and the turning device 30 of the excavator having a large volume and weight. Since the hydraulic oil is not supplied to the swing hydraulic motor 30a, the swing hydraulic motor 30a which continuously rotates serves to pump and suck the pressure oil accumulated in the hydraulic line. The accumulator 60 is installed in the return line 36 of the swing hydraulic motor 30a to accumulate the hydraulic pressure in the return line 36 to recover energy.

At this time, the outlet pressure of the swing hydraulic motor (30a) is controlled by the electromagnetic proportional relief valve 33 installed in the hydraulic line, stored in the accumulator 35 in the constant pressure section, the pressure stored in the accumulator 35 Is maintained below a certain pressure by the pressure reducing valve 34. The pressure oil accumulated in the accumulator 35 can be utilized by opening the pressure of the supply hydraulic line 8b by a sequence valve 37 above a specific pressure.

Finally, when the travel control signal is provided from the controller 7 to the electromagnetic open / close valve 12, the electromagnetic open / close valve 12 installed in the hydraulic line 8c of the main hydraulic pump 2 is opened to open the travel device 26. The hydraulic oil of the main hydraulic pump 2 is supplied to the traveling motors 26a and 26b, and the driving speeds of the driving motors 26a and 26b are supplied through the traveling speed selection valve 40 opened and closed by a signal from the controller. It is controlled by the transmissions 26c and 26d operated by the pressure oil of 5). The traveling speed in the intermediate stage may be controlled by adjusting the flow rate supplied to the traveling motors 26a and 26b by controlling the electronically controlled valve ballast valves 28 and 39 according to the control signal of the controller 7.                     

Both driving motors 26a and 26b of the traveling device 26 are determined by the opening and closing operations of the four solenoid valves n15-n18 and n19-n22, respectively.

As described above, the apparatus according to the present invention can be distributed to a plurality of electronic opening and closing valves and electronically controlled valve ballast valve to secure a central space for installing a hybrid device inside the excavator, electronic control It is possible to secure controllability by constructing an electro-hydraulic system that controls speed regardless of the load by utilizing a ballaster valve, and use the hydraulic system of the existing excavator as the mechanism to drive the turning mechanism. The safety of the system can be secured and the energy recovered can be recovered through the accumulator.

In addition, the slack power of the main hydraulic pump and the discharge flow rates of the two boom cylinders can be converted into electric airbags and recovered through the motor generator.

Accordingly, the present invention is to improve the fuel economy, improve the feasibility and to meet the needs of the future through the system change of the excavator and the lost energy recovery system.

Claims (6)

  1. The engine 4, at least one variable displacement main hydraulic pump 2 and the auxiliary pump 5 driven by the engine 4, and the hydraulic pressure of the main hydraulic pump 2 are bucket cylinder 15, Hybrid hydraulic control system of an excavator including a control valve for controlling distribution to at least one of the front work device 20, the swing device 30, and the travel device 26, such as the arm cylinder 16, the boom cylinder 17, and the like. To
    A motor-generator 6 connected between the engine 4 and the main hydraulic pump 2 so as to generate power by the extra power of the engine 4;
    A battery (3) for storing electricity generated in the motor-generator (6);
    The main hydraulic pump 2 is connected to the hydraulic lines 31, 38, and 40 connecting the main hydraulic pump 2 to the front work device 20, the turning device 30, and the traveling device 26, respectively. A first electromagnetic open / close valve 10, a second electronic open / close valve 12, and a third electronic open / close valve 12 for supplying or blocking a pressurized oil thereof; And
    And a controller (7) for selectively supplying and controlling the pressure oil of the main hydraulic pump (2) to each device by selectively applying a control signal to the first to third electromagnetic open / close valves (10, 11, 12). ,
    The turning device 30 is connected to a return line 36 connecting the swing hydraulic motor 30a, the swing hydraulic motor 30a, and the tank T to accumulate hydraulic pressure of the return line 36 to accumulate energy. Hybrid hydraulic control system of the excavator further comprising; accumulator (60) for recovering.
  2. The engine 4, at least one variable displacement main hydraulic pump 2 and the auxiliary pump 5 driven by the engine 4, and the hydraulic pressure of the main hydraulic pump 2 are bucket cylinder 15, Hybrid hydraulic control system of an excavator including a control valve for controlling distribution to at least one of the front work device 20, the swing device 30, and the travel device 26, such as the arm cylinder 16, the boom cylinder 17, and the like. To
    A motor-generator 6 connected between the engine 4 and the main hydraulic pump 2 so as to generate power by the extra power of the engine 4;
    A battery (3) for storing electricity generated in the motor-generator (6);
    The main hydraulic pump 2 is connected to the hydraulic lines 31, 38, and 40 connecting the main hydraulic pump 2 to the front work device 20, the turning device 30, and the traveling device 26, respectively. A first electromagnetic open / close valve 10, a second electronic open / close valve 12, and a third electronic open / close valve 12 for supplying or blocking a pressurized oil thereof;
    A controller (7) for selectively supplying and controlling the pressure oil of the main hydraulic pump (2) to each device by selectively applying a control signal to the first to third electromagnetic open / close valves (10, 11, 12); And
    Electric power is generated by the hydraulic pump motor 28 driven by the hydraulic oil returning from the front work device 20 to the tank T and the hydraulic pump motor 28 to be stored in the battery 3. The second motor-generator 28a,
    The turning device 30,
    Accumulator 60 connected to a return hydraulic line 30 that connects the swing hydraulic motor 30a, the swing hydraulic motor 30a, and the tank T to accumulate hydraulic pressure in the return line 36 to recover energy. Hybrid hydraulic control system of the excavator, characterized in that it further comprises.
  3. delete
  4. The method according to claim 1 or 2,
    The turning device 30,
    It is composed of a swing hydraulic motor (30a), is installed in the return line 36 for connecting the swing hydraulic motor (30a) and the tank (T) by the control signal of the controller (7) the swing hydraulic motor (30a) Electronic proportional relief valve 33 for controlling the pressure discharged to the tank from the;
    Hybrid hydraulic control system of the excavator further comprising.
  5. 5. The method of claim 4,
    The outlet of the accumulator 60 is connected to the hydraulic line 8b for supplying the hydraulic oil to the swing hydraulic motor 30a, and accumulates in the accumulator 60 supplied to the hydraulic line 8b. Hybrid hydraulic control system of the excavator, characterized in that the compressed oil is controlled by the sequence valve (37).
  6. 5. The method of claim 4,
    Hybrid hydraulic control of the excavator, characterized in that installed; the pressure reducing valve 34 is installed between the accumulator 60 and the feedback line 36 to control the pressure accumulated in the accumulator 60 system.
KR1020040117896A 2004-12-31 2004-12-31 Hybrid system of an excavator KR101155785B1 (en)

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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2014142562A1 (en) * 2013-03-14 2014-09-18 두산인프라코어 주식회사 Hydraulic system for construction machine
WO2014157995A1 (en) * 2013-03-29 2014-10-02 두산인프라코어 주식회사 Method for controlling hydraulic pump of hybrid construction machine
WO2016098926A1 (en) * 2014-12-17 2016-06-23 볼보 컨스트럭션 이큅먼트 에이비 Control method for driving hydraulic actuator of construction machine

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KR101235973B1 (en) * 2011-02-07 2013-02-21 이재수 Dreger system
US9096115B2 (en) * 2011-11-17 2015-08-04 Caterpillar Inc. System and method for energy recovery
US9279236B2 (en) 2012-06-04 2016-03-08 Caterpillar Inc. Electro-hydraulic system for recovering and reusing potential energy
US9290912B2 (en) * 2012-10-31 2016-03-22 Caterpillar Inc. Energy recovery system having integrated boom/swing circuits
US9290911B2 (en) 2013-02-19 2016-03-22 Caterpillar Inc. Energy recovery system for hydraulic machine
WO2018097346A1 (en) * 2016-11-23 2018-05-31 볼보 컨스트럭션 이큅먼트 에이비 Hydraulic control system for construction machine
CN108757593B (en) * 2018-06-12 2020-11-10 北京理工大学 Hydraulic oil supply system of machine tool for rolling and strengthening torsion shaft tooth root

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JPS6367403A (en) 1986-09-05 1988-03-26 Komatsu Ltd Hydraulic device for driving inertia body
KR920004542Y1 (en) * 1988-12-31 1992-07-03 삼성중공업 주식회사 Speed reduction devices of excavator engine
KR20030036186A (en) * 2000-05-23 2003-05-09 코벨코 겐키 가부시키가이샤 Construction machinery
KR20030095219A (en) * 2002-06-04 2003-12-18 가부시키가이샤 고마쓰 세이사쿠쇼 Construction machine

Patent Citations (4)

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Publication number Priority date Publication date Assignee Title
JPS6367403A (en) 1986-09-05 1988-03-26 Komatsu Ltd Hydraulic device for driving inertia body
KR920004542Y1 (en) * 1988-12-31 1992-07-03 삼성중공업 주식회사 Speed reduction devices of excavator engine
KR20030036186A (en) * 2000-05-23 2003-05-09 코벨코 겐키 가부시키가이샤 Construction machinery
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Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2014142562A1 (en) * 2013-03-14 2014-09-18 두산인프라코어 주식회사 Hydraulic system for construction machine
US9829013B2 (en) 2013-03-14 2017-11-28 Doosan Infracore Co., Ltd. Hydraulic system for construction machine
WO2014157995A1 (en) * 2013-03-29 2014-10-02 두산인프라코어 주식회사 Method for controlling hydraulic pump of hybrid construction machine
WO2016098926A1 (en) * 2014-12-17 2016-06-23 볼보 컨스트럭션 이큅먼트 에이비 Control method for driving hydraulic actuator of construction machine

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