WO2014133201A1 - Hydraulic system for contruction equipment - Google Patents

Hydraulic system for contruction equipment Download PDF

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Publication number
WO2014133201A1
WO2014133201A1 PCT/KR2013/001584 KR2013001584W WO2014133201A1 WO 2014133201 A1 WO2014133201 A1 WO 2014133201A1 KR 2013001584 W KR2013001584 W KR 2013001584W WO 2014133201 A1 WO2014133201 A1 WO 2014133201A1
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WIPO (PCT)
Prior art keywords
hydraulic
flow path
hydraulic cylinder
return flow
hydraulic pump
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PCT/KR2013/001584
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French (fr)
Korean (ko)
Inventor
정태랑
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볼보 컨스트럭션 이큅먼트 에이비
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Priority to PCT/KR2013/001584 priority Critical patent/WO2014133201A1/en
Publication of WO2014133201A1 publication Critical patent/WO2014133201A1/en

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    • 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
    • E02F9/2221—Control of flow rate; Load sensing arrangements
    • E02F9/2225—Control of flow rate; Load sensing arrangements using pressure-compensating valves
    • E02F9/2228—Control of flow rate; Load sensing arrangements using pressure-compensating valves including an electronic controller
    • E—FIXED CONSTRUCTIONS
    • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02F—DREDGING; SOIL-SHIFTING
    • E02F9/00—Component parts of dredgers or soil-shifting machines, not restricted to one of the kinds covered by groups E02F3/00 - E02F7/00
    • E02F9/20—Drives; Control devices
    • E02F9/22—Hydraulic or pneumatic drives
    • E02F9/2221—Control of flow rate; Load sensing arrangements
    • E02F9/2232—Control of flow rate; Load sensing arrangements using one or more variable displacement pumps
    • E02F9/2235—Control of flow rate; Load sensing arrangements using one or more variable displacement pumps including an electronic controller
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B11/00—Servomotor systems without provision for follow-up action; Circuits therefor
    • F15B11/02—Systems essentially incorporating special features for controlling the speed or actuating force of an output member
    • F15B11/04—Systems essentially incorporating special features for controlling the speed or actuating force of an output member for controlling the speed
    • F15B11/044—Systems essentially incorporating special features for controlling the speed or actuating force of an output member for controlling the speed by means in the return line, i.e. "meter out"
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/20—Fluid pressure source, e.g. accumulator or variable axial piston pump
    • F15B2211/205—Systems with pumps
    • F15B2211/2053—Type of pump
    • F15B2211/20546—Type of pump variable capacity
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/40—Flow control
    • F15B2211/415—Flow control characterised by the connections of the flow control means in the circuit
    • F15B2211/41581—Flow control characterised by the connections of the flow control means in the circuit being connected to an output member and a return line
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/40—Flow control
    • F15B2211/42—Flow control characterised by the type of actuation
    • F15B2211/426—Flow control characterised by the type of actuation electrically or electronically
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/40—Flow control
    • F15B2211/46—Control of flow in the return line, i.e. meter-out control
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/70—Output members, e.g. hydraulic motors or cylinders or control therefor
    • F15B2211/705—Output members, e.g. hydraulic motors or cylinders or control therefor characterised by the type of output members or actuators
    • F15B2211/7051—Linear output members
    • F15B2211/7053—Double-acting output members

Definitions

  • the present invention relates to a hydraulic system for construction machinery, and more specifically, when the hydraulic oil is supplied to the small chamber of the hydraulic cylinder and the hydraulic oil discharged from the large chamber is returned to the hydraulic oil tank, the back pressure formed in the return passage can be reduced.
  • Hydraulic pumps operated by an engine or the like;
  • a hydraulic cylinder 2 connected to and operated by the hydraulic pump 1;
  • the main control valve is installed in the flow path between the hydraulic pump 1 and the hydraulic cylinder 2 and controls the operation of the hydraulic cylinder 2 when the spool is switched by a control signal according to the operation of the operation lever 3. (4);
  • a controller 6 for outputting a control signal to the hydraulic pump regulator 5 in order to control the discharge flow rate of the hydraulic pump 1.
  • the hydraulic cylinder 2 is contracted by the hydraulic oil supplied from the hydraulic pump (1).
  • the hydraulic oil from the hydraulic pump 1 is the main control valve (4) It passes through and is supplied to the large chamber of the hydraulic cylinder 2.
  • the hydraulic oil discharged from the small chamber of the hydraulic cylinder 2 passes through the main control valve 4 and is returned to the hydraulic oil tank 8 via the return flow path 7.
  • the hydraulic cylinder 2 is extended and driven by the hydraulic oil supplied from the hydraulic pump (1).
  • the present invention is to solve the above-mentioned problems, when the hydraulic oil is supplied to the small chamber of the hydraulic cylinder and the hydraulic oil discharged from the large chamber is returned to the hydraulic tank to reduce the back pressure formed in the return passage to reduce the energy efficiency of the hydraulic system It is an object of the present invention to provide a hydraulic system for construction machinery that can increase the level of oil pressure.
  • a hydraulic cylinder connected to the hydraulic pump and operated
  • a main control valve installed in a flow path between the hydraulic pump and the hydraulic cylinder and controlling the operation of the hydraulic cylinder when switched by a control signal from the outside;
  • a controller for outputting a control signal to a hydraulic pump regulator for controlling the discharge flow rate of the hydraulic pump
  • a valve installed in the auxiliary return flow path, and when the hydraulic oil from the hydraulic pump is supplied to the small chamber of the hydraulic cylinder, the valve is switched by a control signal input from the controller to open the auxiliary return flow path. It provides a hydraulic system for construction machinery, characterized in that the hydraulic oil discharged from the large chamber of the hydraulic cylinder is discharged to the hydraulic oil tank through the return flow path and the auxiliary return flow path.
  • the inlet side of the auxiliary return passage is connected to the return passage and the outlet side is in direct communication with the hydraulic oil tank.
  • the valve is a
  • the inner diameter of the auxiliary return channel is characterized by the following relationship.
  • L A : S A (MR A + AR A ): MR A
  • the energy efficiency and equipment of the hydraulic system are lowered according to the lower back pressure formed in the return flow path. It is effective to increase fuel economy.
  • FIG. 1 is a hydraulic circuit diagram of a hydraulic system for a construction machine according to the prior art
  • FIG. 2 is a hydraulic circuit diagram of a hydraulic system for a construction machine according to an embodiment of the present invention.
  • FIG. 2 is a hydraulic circuit diagram of a hydraulic system for a construction machine according to a preferred embodiment of the present invention.
  • Hydraulic pumps Variable displacement hydraulic pumps (hereinafter referred to as "hydraulic pumps") 11 operated by an engine or the like;
  • a hydraulic cylinder 12 connected to and operated by the hydraulic pump 11;
  • the main control valve is installed in the flow path between the hydraulic pump 11 and the hydraulic cylinder 12 and controls the operation of the hydraulic cylinder 12 when the spool is switched by a control signal according to the operation of the operation lever 13. (14) (MCV);
  • a controller 16 for outputting a control signal to the hydraulic pump regulator 15 to control the discharge flow rate of the hydraulic pump 11;
  • the spool When the hydraulic oil from the hydraulic pump 11 is supplied to the small chamber of the hydraulic cylinder 12, the spool is switched by a control signal input from the controller 16, and the auxiliary return is provided in the auxiliary return flow path 19.
  • the hydraulic oil discharged from the large chamber of the hydraulic cylinder 12 is discharged to the hydraulic oil tank 17 through the return flow path 18 and the auxiliary return flow path 19, including a valve 20 that opens the flow path 19. .
  • the inlet side of the auxiliary return passage 19 can be connected to the return passage 18 and the outlet side of the auxiliary return passage 19 can be in direct communication with the hydraulic oil tank 17.
  • the valve 20 is
  • It may be an on-off solenoid valve that is switched to the state of opening the auxiliary return passage 19 when the control signal is input from the controller 16 after the initial setting to close the auxiliary return passage 19.
  • the inner diameter of the auxiliary return channel 19 can be defined by the following relationship.
  • L A is the cross sectional area of the large chamber of the hydraulic cylinder 12
  • S A is the cross sectional area of the small chamber of the hydraulic cylinder 12
  • MR A is the inner diameter of the return channel 18, and
  • AR A is the auxiliary return channel 19. Inside diameter).
  • the energy efficiency of the hydraulic system is increased by lowering the back pressure formed in the return flow path. It can be effective.

Abstract

Disclosed is a hydraulic system for construction equipment for reducing back pressure formed in a return flow path when working oil is supplied to the small chamber of a hydraulic cylinder such that the working oil discharged from a large chamber is returned to a working oil tank. The present invention provides the hydraulic system for construction equipment, comprising: a hydraulic pump; a hydraulic cylinder which operates by being connected to the hydraulic pump; a main control valve which is provided to a flow path between the hydraulic pump and the hydraulic cylinder and controls the operation of the hydraulic cylinder when being switched by a control signal from the outside; a controller for outputting the control signal to a hydraulic pump regulator so as to control the discharge flow rate of the hydraulic pump; an auxiliary return flow path connected to the return flow path from the main control valve to the working oil tank; and a valve which is provided to the auxiliary return flow path and switched by the control signal inputted from the controller so as to open the auxiliary return flow path when the working oil from the hydraulic pump is supplied to the small chamber of the hydraulic cylinder, wherein the working oil discharged from the large chamber of the hydraulic cylinder is discharged to the working oil tank through the return flow path and the auxiliary return flow path.

Description

건설기계용 유압시스템Hydraulic System for Construction Machinery
본 발명은 건설기계용 유압시스템에 관한 것으로, 보다 구체적으로 설명하면, 유압실린더의 스몰챔버에 작동유가 공급되어 라지챔버로부터 배출되는 작동유가 작동유 탱크로 귀환될 경우 리턴유로에 형성되는 배압을 낮출 수 있도록 한 건설기계용 유압시스템에 관한 것이다.The present invention relates to a hydraulic system for construction machinery, and more specifically, when the hydraulic oil is supplied to the small chamber of the hydraulic cylinder and the hydraulic oil discharged from the large chamber is returned to the hydraulic oil tank, the back pressure formed in the return passage can be reduced. To a hydraulic system for a construction machine.
도 1에 도시된 종래 기술에 의한 건설기계용 유압시스템은,Hydraulic system for construction machinery according to the prior art shown in Figure 1,
엔진 등에 의해 작동되는 가변용량형 유압펌프(이하 "유압펌프" 라고 함)(1);Variable displacement hydraulic pumps (hereinafter referred to as "hydraulic pumps") 1 operated by an engine or the like;
상기 유압펌프(1)에 연결되어 작동되는 유압실린더(2);A hydraulic cylinder 2 connected to and operated by the hydraulic pump 1;
상기 유압펌프(1)와 유압실린더(2) 사이의 유로에 설치되고, 조작레버(3)의 조작에 따른 제어신호에 의해 스풀이 절환될 경우 유압실린더(2)의 작동을 제어하는 메인 콘트롤밸브(4);The main control valve is installed in the flow path between the hydraulic pump 1 and the hydraulic cylinder 2 and controls the operation of the hydraulic cylinder 2 when the spool is switched by a control signal according to the operation of the operation lever 3. (4);
상기 유압펌프(1)의 토출유량을 제어하기 위해 유압펌프 레귤레이터(5)에 제어신호를 출력하는 콘트롤러(6)를 포함한다.And a controller 6 for outputting a control signal to the hydraulic pump regulator 5 in order to control the discharge flow rate of the hydraulic pump 1.
전술한 바와 같은 구성에 따르면, 상기 조작레버(3)를 조작함에 따라 입력되는 제어신호에 의해 메인 콘트롤밸브(4)의 스풀이 도면상, 좌측방향으로 절환될 경우, 상기 유압펌프(1)로부터의 작동유가 메인 콘트롤밸브(4)를 통과하여 유압실린더(2)의 스몰챔버에 공급된다. 이와 동시에 상기 유압실린더(2)의 라지챔버로부터 배출되는 작동유는 메인 콘트롤밸브(4)를 통과하여 리턴유로(7)를 경유하여 작동유 탱크(8)에 귀환된다.According to the configuration as described above, when the spool of the main control valve 4 is switched to the left in the drawing by the control signal input by operating the operation lever (3), from the hydraulic pump (1) The hydraulic fluid of is passed through the main control valve (4) and supplied to the small chamber of the hydraulic cylinder (2). At the same time, the hydraulic oil discharged from the large chamber of the hydraulic cylinder 2 passes through the main control valve 4 and is returned to the hydraulic oil tank 8 via the return passage 7.
따라서 상기 유압실린더(2)는 유압펌프(1)로부터 공급되는 작동유에 의해 수축구동하게 된다.Therefore, the hydraulic cylinder 2 is contracted by the hydraulic oil supplied from the hydraulic pump (1).
또한 상기 조작레버(3)를 조작함에 따른 제어신호에 의해 메인 콘트롤밸브(4)의 스풀이 도면상, 우측방향으로 절환될 경우, 상기 유압펌프(1)로부터의 작동유가 메인 콘트롤밸브(4)를 통과하여 유압실린더(2)의 라지챔버에 공급된다. 이와 동시에 상기 유압실린더(2)의 스몰챔버로부터 배출되는 작동유는 메인 콘트롤밸브(4)를 통과하여 리턴유로(7)를 경유하여 작동유 탱크(8)에 귀환된다.In addition, when the spool of the main control valve 4 is switched to the right in the drawing by the control signal according to the operation of the operating lever 3, the hydraulic oil from the hydraulic pump 1 is the main control valve (4) It passes through and is supplied to the large chamber of the hydraulic cylinder 2. At the same time, the hydraulic oil discharged from the small chamber of the hydraulic cylinder 2 passes through the main control valve 4 and is returned to the hydraulic oil tank 8 via the return flow path 7.
따라서 상기 유압실린더(2)는 유압펌프(1)로부터 공급되는 작동유에 의해 신장구동하게 된다.Therefore, the hydraulic cylinder 2 is extended and driven by the hydraulic oil supplied from the hydraulic pump (1).
한편, 상기 유압실린더(2)의 라지챔버와 스몰챔버의 단면적 비(약 1:2 정도임)의 차이로 인해, 상기 유압실린더(2)의 라지챔버로부터 배출되어 리턴유로(7)를 통하여 작동유 탱크(8)로 귀환되는 유량이 유압실린더(2)의 스몰챔버에 공급되는 유량보다 상대적으로 많게 된다.On the other hand, due to the difference in the ratio of the cross-sectional area of the large chamber and the small chamber (about 1: 2) of the hydraulic cylinder (2), it is discharged from the large chamber of the hydraulic cylinder (2) through the return flow path (7) The flow rate returned to the tank 8 becomes relatively higher than the flow rate supplied to the small chamber of the hydraulic cylinder 2.
이로 인해 상기 리턴유로(7)를 통하여 작동유 탱크(8)로 귀환되는 유량이 증가되고, 증가되는 유량에 의해 유속이 증가되며, 증가된 유속은 압력을 증가시키므로 리턴유로(7) 내에 배압이 상승하게 된다. 따라서 상기 유압실린더(2)의 라지챔버로부터의 작동유가 작동유 탱크(8)로 귀환될 경우 상기 리턴유로(7)에 상승되는 배압으로 인해 유압시스템의 에너지 효율이 떨어지는 문제점을 갖게 된다.As a result, the flow rate returned to the hydraulic oil tank 8 through the return passage 7 is increased, and the flow rate is increased by the increased flow rate, and the increased flow rate increases the pressure so that the back pressure in the return passage 7 is increased. Done. Therefore, when the hydraulic oil from the large chamber of the hydraulic cylinder 2 is returned to the hydraulic oil tank 8, there is a problem that the energy efficiency of the hydraulic system is lowered due to the back pressure raised to the return flow path 7.
따라서, 본 발명은 전술한 문제점을 해결하고자 하는 것으로, 유압실린더의 스몰챔버에 작동유가 공급되어 라지챔버로부터 배출되는 작동유가 작동유 탱크로 귀환될 경우 리턴유로에 형성되는 배압을 낮추어 유압시스템의 에너지 효율을 높일 수 있도록 한 건설기계용 유압시스템을 제공하는 것을 목적으로 한다.Accordingly, the present invention is to solve the above-mentioned problems, when the hydraulic oil is supplied to the small chamber of the hydraulic cylinder and the hydraulic oil discharged from the large chamber is returned to the hydraulic tank to reduce the back pressure formed in the return passage to reduce the energy efficiency of the hydraulic system It is an object of the present invention to provide a hydraulic system for construction machinery that can increase the level of oil pressure.
상기 및 기타 본 발명의 목적을 달성하기 위하여 본 발명의 일 실시예에 따르면,According to one embodiment of the present invention to achieve the above and other objects of the present invention,
유압펌프;Hydraulic pump;
상기 유압펌프에 연결되어 작동되는 유압실린더;A hydraulic cylinder connected to the hydraulic pump and operated;
상기 유압펌프와 유압실린더 사이의 유로에 설치되고 외부로부터의 제어신호에 의해 절환될 경우 상기 유압실린더의 작동을 제어하는 메인 콘트롤밸브;A main control valve installed in a flow path between the hydraulic pump and the hydraulic cylinder and controlling the operation of the hydraulic cylinder when switched by a control signal from the outside;
상기 유압펌프의 토출유량을 제어하기 위해 유압펌프 레귤레이터에 제어신호를 출력하는 콘트롤러;A controller for outputting a control signal to a hydraulic pump regulator for controlling the discharge flow rate of the hydraulic pump;
상기 메인 콘트롤밸브로부터 작동유 탱크로의 리턴유로에 접속되는 보조 리턴유로; 및An auxiliary return passage connected to the return passage from the main control valve to the hydraulic oil tank; And
상기 보조 리턴유로에 설치되고, 상기 유압펌프로부터의 작동유가 상기 유압실린더의 스몰챔버에 공급될 경우, 상기 콘트롤러로부터 입력되는 제어신호에 의해 절환되어 상기 보조 리턴유로를 개방하는 밸브를 포함하여, 상기 유압실린더의 라지챔버로부터 배출되는 작동유가 상기 리턴유로와 보조 리턴유로를 통하여 상기 작동유 탱크로 배출되는 것을 특징으로 하는 건설기계용 유압시스템을 제공한다.And a valve installed in the auxiliary return flow path, and when the hydraulic oil from the hydraulic pump is supplied to the small chamber of the hydraulic cylinder, the valve is switched by a control signal input from the controller to open the auxiliary return flow path. It provides a hydraulic system for construction machinery, characterized in that the hydraulic oil discharged from the large chamber of the hydraulic cylinder is discharged to the hydraulic oil tank through the return flow path and the auxiliary return flow path.
상기 보조 리턴유로의 입구측은 상기 리턴유로에 접속되고 출구측은 상기 작동유 탱크에 직접 연통되는 것을 특징으로 한다.The inlet side of the auxiliary return passage is connected to the return passage and the outlet side is in direct communication with the hydraulic oil tank.
상기 밸브는The valve is
상기 보조 리턴유로를 폐쇄하는 상태로 초기 설정된 후, 상기 콘트롤러로부터 제어신호가 입력될 경우 상기 보조 리턴유로를 개방하는 상태로 절환되는 온,오프형 솔레노이드밸브인 것을 특징으로 한다.After the initial setting to close the auxiliary return flow path, when the control signal is input from the controller is characterized in that the on, off type solenoid valve is switched to open the auxiliary return flow path.
상기 보조 리턴유로의 내경은 아래의 관계식에 의해 정의되는 것을 특징으로 한다. LA : SA = (MRA + ARA) : MRA The inner diameter of the auxiliary return channel is characterized by the following relationship. L A : S A = (MR A + AR A ): MR A
(이때 LA: 유압실린더의 라지챔버의 단면적, SA: 유압실린더의 스몰챔버의 단면적, MRA: 리턴유로의 내경, ARA: 보조 리턴유로의 내경).(L A : cross-sectional area of the large chamber of the hydraulic cylinder, S A : cross-sectional area of the small chamber of the hydraulic cylinder, MR A : the inner diameter of the return flow path, AR A : the inner diameter of the auxiliary return flow path).
전술한 구성을 갖는 본 발명에 따르면, 유압실린더의 스몰챔버에 작동유가 공급되어 라지챔버로부터 배출되는 작동유가 작동유 탱크로 귀환될 경우 리턴유로에 형성되는 배압을 낮춤에 따라 유압시스템의 에너지 효율 및 장비의 연비를 높일 수 있는 효과가 있다.According to the present invention having the above-described configuration, when hydraulic oil is supplied to the small chamber of the hydraulic cylinder and the hydraulic oil discharged from the large chamber is returned to the hydraulic tank, the energy efficiency and equipment of the hydraulic system are lowered according to the lower back pressure formed in the return flow path. It is effective to increase fuel economy.
도 1은 종래 기술에 의한 건설기계용 유압시스템의 유압회로도,1 is a hydraulic circuit diagram of a hydraulic system for a construction machine according to the prior art,
도 2는 본 발명의 일 실시예에 의한 건설기계용 유압시스템의 유압회로도이다.2 is a hydraulic circuit diagram of a hydraulic system for a construction machine according to an embodiment of the present invention.
〈도면의 주요 부분에 대한 참조 부호의 설명〉<Explanation of reference numerals for the main parts of the drawings>
11; 유압펌프11; Hydraulic pump
12; 유압실린더12; Hydraulic cylinder
13; 조작레버13; Operation lever
14; 메인 콘트롤밸브14; Main control valve
15; 유압펌프 레귤레이터15; Hydraulic Pump Regulator
16; 콘트롤러16; Controller
17; 작동유 탱크17; Hydraulic oil tank
18; 리턴유로18; Return euro
19; 보조 리턴유로19; Secondary return euro
20; 밸브20; valve
이하, 첨부도면을 참조하여 본 발명의 바람직한 실시예에 따른 건설기계용 유압시스템을 상세히 설명하기로 한다.Hereinafter, a hydraulic system for construction machinery according to a preferred embodiment of the present invention with reference to the accompanying drawings will be described in detail.
도 2는 본 발명의 바람직한 실시예에 의한 건설기계용 유압시스템의 유압회로도이다.2 is a hydraulic circuit diagram of a hydraulic system for a construction machine according to a preferred embodiment of the present invention.
도 2를 참조하면, 본 발명의 일 실시예에 따른 건설기계용 유압시스템은2, the hydraulic system for construction machinery according to an embodiment of the present invention
엔진 등에 의해 작동되는 가변용량형 유압펌프(이하 "유압펌프" 라고 함)(11);Variable displacement hydraulic pumps (hereinafter referred to as "hydraulic pumps") 11 operated by an engine or the like;
상기 유압펌프(11)에 연결되어 작동되는 유압실린더(12);A hydraulic cylinder 12 connected to and operated by the hydraulic pump 11;
상기 유압펌프(11)와 유압실린더(12) 사이의 유로에 설치되고, 조작레버(13)의 조작에 따른 제어신호에 의해 스풀이 절환될 경우 유압실린더(12)의 작동을 제어하는 메인 콘트롤밸브(14)(MCV);The main control valve is installed in the flow path between the hydraulic pump 11 and the hydraulic cylinder 12 and controls the operation of the hydraulic cylinder 12 when the spool is switched by a control signal according to the operation of the operation lever 13. (14) (MCV);
상기 유압펌프(11)의 토출유량을 제어하기 위해 유압펌프 레귤레이터(15)에 제어신호를 출력하는 콘트롤러(16);A controller 16 for outputting a control signal to the hydraulic pump regulator 15 to control the discharge flow rate of the hydraulic pump 11;
상기 메인 콘트롤밸브(14)로부터 작동유 탱크(17)로의 리턴유로(18)에 접속되는 보조 리턴유로(19); 및An auxiliary return flow path (19) connected to the return flow path (18) from the main control valve (14) to the hydraulic oil tank (17); And
상기 보조 리턴유로(19)에 설치되고, 유압펌프(11)로부터의 작동유가 유압실린더(12)의 스몰챔버에 공급될 경우, 콘트롤러(16)로부터 입력되는 제어신호에 의해 스풀이 절환되어 보조 리턴유로(19)를 개방하는 밸브(20)를 포함하여, 유압실린더(12)의 라지챔버로부터 배출되는 작동유가 리턴유로(18)와 보조 리턴유로(19)를 통하여 작동유 탱크(17)로 배출된다.When the hydraulic oil from the hydraulic pump 11 is supplied to the small chamber of the hydraulic cylinder 12, the spool is switched by a control signal input from the controller 16, and the auxiliary return is provided in the auxiliary return flow path 19. The hydraulic oil discharged from the large chamber of the hydraulic cylinder 12 is discharged to the hydraulic oil tank 17 through the return flow path 18 and the auxiliary return flow path 19, including a valve 20 that opens the flow path 19. .
상기 보조 리턴유로(19)의 입구측은 리턴유로(18)에 접속되고 보조 리턴유로(19)의 출구측은 작동유 탱크(17)에 직접 연통될 수 있다.The inlet side of the auxiliary return passage 19 can be connected to the return passage 18 and the outlet side of the auxiliary return passage 19 can be in direct communication with the hydraulic oil tank 17.
상기 밸브(20)는The valve 20 is
상기 보조 리턴유로(19)를 폐쇄하는 상태로 초기 설정된 후, 콘트롤러(16)로부터 제어신호가 입력될 경우 보조 리턴유로(19)를 개방하는 상태로 절환되는 온,오프형 솔레노이드밸브일 수 있다.It may be an on-off solenoid valve that is switched to the state of opening the auxiliary return passage 19 when the control signal is input from the controller 16 after the initial setting to close the auxiliary return passage 19.
상기 보조 리턴유로(19)의 내경은 아래의 관계식에 의해 정의될 수 있다.The inner diameter of the auxiliary return channel 19 can be defined by the following relationship.
LA SA := (MRA + ARA) : MRA L A S A : = (MR A + AR A ): MR A
(이때 LA: 유압실린더(12)의 라지챔버의 단면적, SA: 유압실린더(12)의 스몰챔버의 단면적, MRA: 리턴유로(18)의 내경, ARA: 보조 리턴유로(19)의 내경).Where L A is the cross sectional area of the large chamber of the hydraulic cylinder 12, S A is the cross sectional area of the small chamber of the hydraulic cylinder 12, MR A is the inner diameter of the return channel 18, and AR A is the auxiliary return channel 19. Inside diameter).
이하에서, 본 발명의 일 실시예에 의한 건설기계용 유압시스템의 작동을 첨부도면을 참조하여 상세하게 설명한다.Hereinafter, the operation of the hydraulic system for construction machinery according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.
상기 조작레버(13)를 조작함에 따라 입력되는 제어신호에 의해 메인 콘트롤밸브(14)의 스풀이 도면상, 좌측방향으로 절환될 경우(도 2에서와 같이 절환됨), 유압펌프(11)로부터의 작동유가 메인 콘트롤밸브(14)를 통과하여 유압실린더(12)의 스몰챔버에 공급된다. 이때 상기 콘트롤러(16)로부터 입력되는 제어신호에 의해 상기 보조 리턴유로(19)에 설치된 밸브(20)의 스풀이 절환되어 보조 리턴유로(19)를 개방하게 된다. 따라서 상기 유압실린더(12)의 라지챔버로부터 배출되는 작동유 일부는 메인콘트롤밸브(14)를 통과하여 리턴유로(18)를 경유하여 작동유 탱크(17)에 귀환된다. 또한 상기 유압실린더(12)의 라지챔버로부터 배출되는 작동유 일부는 메인 콘트롤밸브(14)를 통과하여 보조 리턴유로(19)에 설치된 밸브(20)를 경유하여 작동유 탱크(17)에 귀환된다.When the spool of the main control valve 14 is switched in the left direction in the drawing (switched as in FIG. 2) by the control signal input by operating the operation lever 13, from the hydraulic pump 11 The hydraulic fluid of is passed through the main control valve 14 and is supplied to the small chamber of the hydraulic cylinder 12. At this time, the spool of the valve 20 installed in the auxiliary return channel 19 is switched by the control signal input from the controller 16 to open the auxiliary return channel 19. Therefore, a part of the hydraulic oil discharged from the large chamber of the hydraulic cylinder 12 passes through the main control valve 14 and is returned to the hydraulic oil tank 17 via the return flow path 18. In addition, a part of the hydraulic oil discharged from the large chamber of the hydraulic cylinder 12 passes through the main control valve 14 and is returned to the hydraulic oil tank 17 via the valve 20 installed in the auxiliary return flow path 19.
따라서 상기 유압실린더(12)는 유압펌프(11)로부터 공급되는 작동유에 의해 수축구동하게 된다.Therefore, the hydraulic cylinder 12 is contracted and driven by the hydraulic oil supplied from the hydraulic pump (11).
한편 상기 조작레버(13)를 조작함에 따른 제어신호에 의해 메인 콘트롤밸브(14)의 스풀이 도면상, 우측방향으로 절환될 경우, 유압펌프(11)로부터의 작동유가 메인콘트롤밸브(14)를 통과하여 유압실린더(12)의 라지챔버에 공급된다. 이와 동시에 상기 유압실린더(12)의 스몰챔버로부터 배출되는 작동유는 메인 콘트롤밸브(14)를 통과하여 리턴유로(18)를 경유하여 작동유 탱크(17)에 귀환된다(이때 상기 보조 리턴유로(19)는 초기 설정상태를 유지하는 밸브(20)에 의해 막혀 있음).On the other hand, when the spool of the main control valve 14 is switched in the right direction in the drawing by the control signal according to the operation lever 13, the hydraulic oil from the hydraulic pump 11 to the main control valve 14 It passes and is supplied to the large chamber of the hydraulic cylinder 12. At the same time, the hydraulic oil discharged from the small chamber of the hydraulic cylinder 12 passes through the main control valve 14 and is returned to the hydraulic oil tank 17 via the return flow path 18 (the auxiliary return flow path 19 at this time). Is blocked by the valve 20 to maintain the initial setting.
따라서 상기 유압실린더(12)는 유압펌프(11)로부터 공급되는 작동유에 의해 신장구동하게 된다.Therefore, the hydraulic cylinder 12 is extended and driven by the hydraulic oil supplied from the hydraulic pump (11).
전술한 바와 같이 상기 유압펌프(11)로부터의 작동유가 유압실린더(12)의 스몰챔버에 공급될 경우, 유압실린더(12)의 라지챔버로부터 배출되는 작동유가 리턴유로(18)와 보조 리턴유로(19)를 경유하여 작동유 탱크(17)로 신속하게 귀환할 수 있게 된다. 따라서 상기 유압실린더(12)의 라지챔버와 스몰챔버의 단면적 비의 차이로 인해 상기 유압실린더(2)의 스몰챔버에 공급되는 유량보다 라지챔버로부터 작동유 탱크(17)로 배출되는 유량이 많을 경우에도 리턴유로(18)에 형성되는 배압을 낮출 수 있게 된다.As described above, when the hydraulic oil from the hydraulic pump 11 is supplied to the small chamber of the hydraulic cylinder 12, the hydraulic oil discharged from the large chamber of the hydraulic cylinder 12 returns the return passage 18 and the auxiliary return passage ( It is possible to quickly return to the hydraulic oil tank 17 via 19). Therefore, even when the flow rate discharged from the large chamber to the hydraulic oil tank 17 is greater than the flow rate supplied to the small chamber of the hydraulic cylinder 2 due to the difference in the cross sectional area ratio between the large chamber and the small chamber of the hydraulic cylinder 12. The back pressure formed in the return flow path 18 can be lowered.
여기에서, 상술한 본 발명에서는 바람직한 실시예를 참조하여 설명하였지만, 해당 기술분야에서 숙련된 당업자는 하기의 특허청구범위에 기재된 본 발명의 사상 및 영역으로부터 벗어나지 않는 범위 내에서 본 발명을 다양하게 수정 및 변경할 수 있음을 이해할 수 있을 것이다.Herein, while the present invention has been described with reference to the preferred embodiments, those skilled in the art will variously modify the present invention without departing from the spirit and scope of the invention as set forth in the claims below. And can be changed.
전술한 구성을 갖는 본 발명에 따르면, 유압실린더의 스몰챔버에 작동유가 공급되어 라지챔버로부터 배출되는 작동유가 작동유 탱크로 귀환될 경우 리턴유로에 형성되는 배압을 낮춤에 따라 유압시스템의 에너지 효율을 높일 수 있는 효과가 있다.According to the present invention having the above-described configuration, when the hydraulic oil is supplied to the small chamber of the hydraulic cylinder and the hydraulic oil discharged from the large chamber is returned to the hydraulic oil tank, the energy efficiency of the hydraulic system is increased by lowering the back pressure formed in the return flow path. It can be effective.

Claims (4)

  1. 유압펌프;Hydraulic pump;
    상기 유압펌프에 연결되어 작동되는 유압실린더;A hydraulic cylinder connected to the hydraulic pump and operated;
    상기 유압펌프와 유압실린더 사이의 유로에 설치되고 외부로부터의 제어신호에 의해 절환될 경우 상기 유압실린더의 작동을 제어하는 메인 콘트롤밸브;A main control valve installed in a flow path between the hydraulic pump and the hydraulic cylinder and controlling the operation of the hydraulic cylinder when switched by a control signal from the outside;
    상기 유압펌프의 토출유량을 제어하기 위해 유압펌프 레귤레이터에 제어신호를 출력하는 콘트롤러;A controller for outputting a control signal to a hydraulic pump regulator for controlling the discharge flow rate of the hydraulic pump;
    상기 메인 콘트롤밸브로부터 작동유 탱크로의 리턴유로에 접속되는 보조 리턴유로; 및An auxiliary return passage connected to the return passage from the main control valve to the hydraulic oil tank; And
    상기 보조 리턴유로에 설치되고, 상기 유압펌프로부터의 작동유가 상기 유압실린더의 스몰챔버에 공급될 경우, 상기 콘트롤러로부터 입력되는 제어신호에 의해 절환되어 상기 보조 리턴유로를 개방하는 밸브를 포함하여, 상기 유압실린더의 라지챔버로부터 배출되는 작동유가 상기 리턴유로와 보조 리턴유로를 통하여 상기 작동유 탱크로 배출되는 것을 특징으로 하는 건설기계용 유압시스템.And a valve installed in the auxiliary return flow path, and when the hydraulic oil from the hydraulic pump is supplied to the small chamber of the hydraulic cylinder, the valve is switched by a control signal input from the controller to open the auxiliary return flow path. And hydraulic fluid discharged from the large chamber of the hydraulic cylinder is discharged to the hydraulic oil tank through the return flow path and the auxiliary return flow path.
  2. 제1항에 있어서, 상기 보조 리턴유로의 입구측은 상기 리턴유로에 접속되고 출구측은 상기 작동유 탱크에 직접 연통되는 것을 특징으로 하는 건설기계용 유압시스템.The hydraulic system for a construction machine according to claim 1, wherein the inlet side of the auxiliary return passage is connected to the return passage and the outlet side is directly communicated with the hydraulic oil tank.
  3. 제1항에 있어서, 상기 밸브는The method of claim 1, wherein the valve
    상기 보조 리턴유로를 폐쇄하는 상태로 초기 설정된 후, 상기 콘트롤러로부터 제어신호가 입력될 경우 상기 보조 리턴유로를 개방하는 상태로 절환되는 온,오프형 솔레노이드밸브인 것을 특징으로 하는 건설기계용 유압시스템.And an on / off solenoid valve which is switched to open the auxiliary return flow path when a control signal is input from the controller after the initial setting to close the auxiliary return flow path.
  4. 제1항에 있어서, 상기 보조 리턴유로의 내경은 아래의 관계식에 의해 정의되는 것을 특징으로 하는 건설기계의 유압시스템.The hydraulic system of a construction machine according to claim 1, wherein the inner diameter of the auxiliary return flow path is defined by the following relational expression.
    LA : SA = (MRA + ARA) : MRA L A : S A = (MR A + AR A ): MR A
    (이때 LA: 유압실린더의 라지챔버의 단면적, SA: 유압실린더의 스몰챔버의 단면적, MRA: 리턴유로의 내경, ARA: 보조 리턴유로의 내경)(At this time, L A : cross section of the large chamber of the hydraulic cylinder, S A : cross section of the small chamber of the hydraulic cylinder, MR A : inner diameter of the return passage, AR A : inner diameter of the auxiliary return passage)
PCT/KR2013/001584 2013-02-27 2013-02-27 Hydraulic system for contruction equipment WO2014133201A1 (en)

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Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR19990031196A (en) * 1997-10-09 1999-05-06 김형벽 Apparatus for alleviating the impact generated during the boom lowering operation of the excavator
JP2002339904A (en) * 2001-05-21 2002-11-27 Komatsu Ltd Hydraulic circuit for construction machine
JP2010216608A (en) * 2009-03-18 2010-09-30 Caterpillar Sarl Circuit for removing air bubble in hydraulic oil
KR20100130034A (en) * 2009-06-02 2010-12-10 볼보 컨스트럭션 이큅먼트 에이비 Excavator with hammer device
JP2013007175A (en) * 2011-06-23 2013-01-10 Kobelco Contstruction Machinery Ltd Work machine

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR19990031196A (en) * 1997-10-09 1999-05-06 김형벽 Apparatus for alleviating the impact generated during the boom lowering operation of the excavator
JP2002339904A (en) * 2001-05-21 2002-11-27 Komatsu Ltd Hydraulic circuit for construction machine
JP2010216608A (en) * 2009-03-18 2010-09-30 Caterpillar Sarl Circuit for removing air bubble in hydraulic oil
KR20100130034A (en) * 2009-06-02 2010-12-10 볼보 컨스트럭션 이큅먼트 에이비 Excavator with hammer device
JP2013007175A (en) * 2011-06-23 2013-01-10 Kobelco Contstruction Machinery Ltd Work machine

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