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WO2017099265A1 - Hydraulic system for construction machine - Google Patents

Hydraulic system for construction machine Download PDF

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Publication number
WO2017099265A1
WO2017099265A1 PCT/KR2015/013360 KR2015013360W WO2017099265A1 WO 2017099265 A1 WO2017099265 A1 WO 2017099265A1 KR 2015013360 W KR2015013360 W KR 2015013360W WO 2017099265 A1 WO2017099265 A1 WO 2017099265A1
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WO
WIPO (PCT)
Prior art keywords
hydraulic
cylinder
hydraulic oil
flow path
accumulator
Prior art date
Application number
PCT/KR2015/013360
Other languages
French (fr)
Korean (ko)
Inventor
김재홍
이재용
Original Assignee
볼보 컨스트럭션 이큅먼트 에이비
김재홍
이재용
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 볼보 컨스트럭션 이큅먼트 에이비, 김재홍, 이재용 filed Critical 볼보 컨스트럭션 이큅먼트 에이비
Priority to PCT/KR2015/013360 priority Critical patent/WO2017099265A1/en
Publication of WO2017099265A1 publication Critical patent/WO2017099265A1/en

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Classifications

    • E—FIXED CONSTRUCTIONS
    • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02F—DREDGING; SOIL-SHIFTING
    • E02F9/00—Component parts of dredgers or soil-shifting machines, not restricted to one of the kinds covered by groups E02F3/00 - E02F7/00
    • E02F9/08—Superstructures; Supports for superstructures
    • E02F9/10—Supports for movable superstructures mounted on travelling or walking gears or on other superstructures
    • E02F9/12—Slewing or traversing gears
    • 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
    • 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
    • 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
    • F15B13/00—Details of servomotor systems ; Valves for servomotor systems
    • F15B13/02—Fluid distribution or supply devices characterised by their adaptation to the control of servomotors

Definitions

  • the present invention relates to a hydraulic system for construction machinery, and more particularly, to a hydraulic system for construction machinery that can implement a boost function using an accumulator.
  • an accumulator is used to store hydraulic energy during turning deceleration or boom lowering.
  • the hydraulic oil flowing into the first port and discharged from the second port is stored in the accumulator, and the swinging motor continuously continues due to the large weight and rotational inertia of the upper swinging body.
  • the hydraulic oil is sucked and replenished from the hydraulic tank to the first port where the hydraulic oil supply from the hydraulic pump is stopped.
  • the hydraulic oil flowing into the second port and discharged from the first port is stored in the accumulator, and likewise, in the second port where the hydraulic oil supply from the hydraulic pump is stopped. Hydraulic fluid is sucked and refilled from the hydraulic tank.
  • an electric motor, a hydraulic pump, and a low pressure accumulator are used to implement a boost function for supplying a suddenly required hydraulic fluid to the swing motor due to continuous rotation of the upper swing body.
  • the present invention has been made to solve the problems of the prior art as described above, an object of the present invention to provide a hydraulic system for construction machinery that can implement a boost function using an accumulator.
  • a hydraulic actuator is connected to the hydraulic pump, driven by the operating oil discharged from the hydraulic pump supplied to the hydraulic tank;
  • a flow control valve installed on the hydraulic pump and the hydraulic actuator and a moving path of the hydraulic oil moving between the hydraulic actuator and the hydraulic tank to control the movement of the hydraulic oil;
  • An accumulator installed in the regeneration passage branched from the movement path of the hydraulic oil directed to the hydraulic tank and storing the hydraulic oil flowing into the regeneration passage when the flow control valve is switched to the neutral position; And hydraulic fluid stored in the accumulator, when the hydraulic fluid discharged from the hydraulic pump is not supplied to the hydraulic actuator, when the flow control valve is switched to the neutral position and is connected to the accumulator.
  • a hydraulic system for a construction machine comprising a boost device for supplying a hydraulic oil shortage required by the continuous operation to the hydraulic actuator.
  • the boost device the first cylinder is connected to the accumulator, the first cylinder is connected to the first cylinder is formed with a relatively larger area than the first cylinder when the hydraulic fluid is supplied from the accumulator therein
  • a second cylinder for discharging the filled hydraulic oil to the hydraulic actuator side and is provided between the first cylinder and the second cylinder in a form of connecting the first cylinder and the second cylinder, and is supplied to the first cylinder; Or a piston reciprocating between the first cylinder and the second cylinder by the hydraulic oil filled in the second cylinder.
  • the first cylinder and the second cylinder may be formed in the form of one body or may be formed in an independent form.
  • the boost device is installed in a first supply passage connecting between the accumulator and the first cylinder, the spool controlling hydraulic oil movement from the accumulator to the first cylinder and hydraulic oil movement from the first cylinder to the hydraulic tank.
  • the valve may further include.
  • the second cylinder may be connected to the hydraulic actuator through a second supply passage.
  • the second cylinder may be connected to the MCV return passage through a third supply passage connected to the second supply passage.
  • the third supply passage may include a first check valve to allow a hydraulic oil movement in one direction from the MCV return flow passage to the second cylinder side.
  • the hydraulic oil for moving the MCV return flow path may be automatically filled in the second cylinder according to the pressure difference.
  • the hydraulic actuator may be a swing motor or a hydraulic cylinder for attachment.
  • It may further include a first flow path and a second flow path for connecting the hydraulic pump and the hydraulic actuator.
  • Both ends are branch-connected to the first flow path and the second flow path, and second and third check valves are respectively provided to allow movement of hydraulic fluid in one direction from the boost device to the first flow path and the second flow path.
  • a third flow path being formed in parallel with the third flow path, and both ends are connected to an upstream side of the first flow path and the second flow path, and the first flow path or the second flow path is connected to the hydraulic tank.
  • the apparatus may further include a fourth flow path in which fourth and fifth check valves respectively allowing movement of the hydraulic fluid in one direction are installed.
  • It may further include an intermittent valve installed in the regeneration passage between the accumulator and the hydraulic motor connected to the engine to control the opening and closing of the regeneration passage.
  • the apparatus may further include a pressure sensor installed in an upstream side of the accumulator and detecting a pressure of the regenerative passage.
  • variable relief valve installed in the regeneration passage upstream of the pressure sensor and variably adjusting a pressure difference between the inlet port and the outlet port by a control signal value set based on the pressure value detected by the pressure sensor.
  • the present invention by implementing a boost function using an accumulator, for example, when sharply reducing the turning of the upper turning body, as the turning motor continues to operate due to the large weight of the upper turning body and the rotational inertia, suddenly required
  • the operating oil can be supplied to the turning motor instantaneously without a separate complicated electrical device, thereby ensuring the stability of the device.
  • FIG. 1 is a hydraulic circuit diagram showing a hydraulic system for a construction machine according to an embodiment of the present invention.
  • Figure 2 is a graph showing the change in pressure of the inlet side of the swing motor during loading operation using an excavator.
  • FIG. 3 is a hydraulic circuit diagram showing a hydraulic system for a construction machine according to another embodiment of the present invention.
  • the hydraulic system 100 for a construction machine is a system for controlling the operation of a construction machine such as an excavator through hydraulic pressure, and includes a hydraulic actuator and a flow control valve. 120, an accumulator 130, and a boost device 140.
  • the swing motor 110 is illustrated as a hydraulic actuator, but is not limited thereto. That is, the hydraulic actuator may be, for example, an attachment hydraulic cylinder including an boom, an arm and a bucket of the excavator.
  • the swing motor 110 used as the hydraulic actuator is a motor for turning the upper swing body 20 mounted on the lower traveling body (not shown) in the forward or reverse direction.
  • the swing motor 110 is connected to the hydraulic pump (11). Accordingly, the swing motor 110 is driven by the hydraulic oil discharged from the hydraulic pump 11 and supplied to the A port, discharged from the B port and returned to the hydraulic tank 13.
  • the hydraulic pump 11 is a variable displacement hydraulic pump, it is connected to the engine (10).
  • the hydraulic motor 12 is connected to the engine 10.
  • Flow control valve 120 is a valve for controlling the movement of the working oil.
  • the flow control valve 120 is installed on the hydraulic pump 11 and the swinging motor 110 and the movement path of the hydraulic oil moving between the swinging motor 110 and the hydraulic tank (13).
  • the flow control valve 120 is installed in the first flow path 185 and the second flow path 186 connecting the hydraulic pump 11 and the swing motor 110.
  • the flow control valve 120 is switched by the pilot signal pressure applied to the port formed on one side in the longitudinal direction, the hydraulic oil discharged from the hydraulic pump 11 is pivoting motor 110 through the first flow path (185) It is supplied to the A port of the and is discharged from the B port of the swing motor 110 to be able to return to the hydraulic tank 13 through the second flow path (186).
  • the turning motor 110 rotates in the forward direction, and accordingly, the upper swinging body 20 performs the turning operation in the forward direction.
  • the flow control valve 120 is switched by the pilot signal pressure applied to the port formed on the other side in the longitudinal direction, so that the hydraulic oil is supplied to the B port of the swing motor 110 through the second flow path 186 and swings. It is discharged from the A port of the motor 110 to enable the return to the hydraulic tank 13 through the first flow path (185).
  • the turning motor 110 rotates in the reverse direction, and accordingly, the upper swinging body 20 performs the turning operation in the reverse direction.
  • the flow control valve 120 is switched to neutral by the pilot signal pressure applied from the outside, and shuts off the supply of hydraulic oil from the hydraulic pump 11 to the swing motor 110. Through this, the rotation of the swing motor 110 and the swing operation of the upper swing body 20 is stopped. As such, the flow control valve 120 controls the rotation, stop and direction change of the swing motor 110.
  • the hydraulic system 100 of a construction machine may include a third flow path (187). Both ends of the third flow path 187 are connected to the first flow path 185 and the second flow path 186.
  • the third flow path 187 includes a second check valve 22 that allows the hydraulic fluid to move in one direction from the boost device 140 to the first flow path 185, and the second flow path 186 from the boost device 140.
  • a third check valve 23 may be installed to allow the hydraulic oil to move in one direction to the side.
  • the hydraulic system 100 of the construction machine according to an embodiment of the present invention may include a fourth flow path (188).
  • the fourth flow path 188 is parallel to the third flow path 187, and both ends thereof are branched to the upstream side of the first flow path 185 and the second flow path 186.
  • the fourth flow path 188 includes a fourth check valve 24 that allows the hydraulic fluid to move in one direction from the first flow path 185 to the accumulator 130, and from the second flow path 186 to the accumulator 130.
  • a fifth check valve 25 may be installed to allow the hydraulic oil to move in one direction.
  • the accumulator 130 is installed in the regeneration passage 181 branched from the movement path of the hydraulic oil toward the hydraulic tank 13. Specifically, the accumulator 130 has one end connected to the fourth flow path 188 between the fourth check valve 24 and the fifth check valve 25 and the other end connected to the hydraulic motor 12 which is an assist motor. It is installed in the regeneration passage 181. When the flow control valve 120 is switched to the neutral position, the accumulator 130 stores the hydraulic oil flowing into the regeneration passage 181 according to the overload generated in the first flow passage 185 or the second flow passage 186. do.
  • the hydraulic oil stored in the accumulator 130 may be supplied to the hydraulic motor 12.
  • the pressure of the accumulator 130 is greater than or equal to a predetermined pressure
  • the hydraulic oil stored in the accumulator 130 may be supplied to the hydraulic motor 12, thereby reducing the load of the engine 10.
  • the hydraulic oil stored in the accumulator 130 may be supplied to the boost device 140 when the upper swing body 20 decelerates turning, which will be described in more detail below.
  • the boost device 140 is a device that implements a boost function using the accumulator 130 and is connected to the accumulator 130. That is, in the boost device 140, the flow control valve 120 is switched to the neutral position to reduce the turning speed of the upper swing body 20 so that the hydraulic oil discharged from the hydraulic pump 11 may not be supplied to the swing motor 110. In this case, by using the hydraulic oil stored in the accumulator 130, the hydraulic oil shortage required by the continuous operation of the swing motor 110 generated by the large weight of the upper swing body 20 and the rotational inertia force is rotated motor 110 Supplies).
  • the boost device 140 may include a first cylinder 141, a second cylinder 142, and a piston 143.
  • the first cylinder 141 is connected to the accumulator 130.
  • the second cylinder 142 is connected to the first cylinder 141.
  • the second cylinder 142 is formed with a relatively larger area than the first cylinder 141.
  • the piston 143 is formed to partition these spaces between the first cylinder 141 and the second cylinder 142, which are formed in one body.
  • the piston 143 reciprocates between the first cylinder 141 and the second cylinder 142 by the hydraulic oil supplied to the first cylinder 141 or filled in the second cylinder 142.
  • the boost device 140 further includes a spool valve 144.
  • the spool valve 144 is installed in the first supply passage 182 connecting between the accumulator 130 and the first cylinder 141.
  • the spool valve 144 controls the movement of the hydraulic oil from the accumulator 130 to the first cylinder 141, and controls the movement of the hydraulic oil from the first cylinder 141 to the hydraulic tank 13.
  • the second cylinder 142 is connected to the swing motor 110 through the second supply passage (183).
  • the second cylinder 142 is connected to the main control valve (MCV) return passage 15 through a third supply passage 184 connected to the second supply passage 183.
  • the third supply passage 184 may include a first check valve 21 installed to allow movement of the hydraulic oil in one direction from the MCV return flow passage 15 to the second cylinder 142.
  • the spool valve 144 when the spool valve 144 is switched so that the hydraulic oil can be moved from the first cylinder 141 to the hydraulic tank 13, the pressure is not formed in the first cylinder 141 and the MCV return flow path 15 of the Since the pressure is always maintained at about 3-7 bar, the hydraulic fluid moving the MCV return flow path 15 is automatically filled in the second cylinder 142 according to the pressure difference.
  • the hydraulic system 100 for construction machinery may include an intermittent valve 150.
  • the intermittent valve 150 is installed in the regeneration passage 181 between the accumulator 130 and the hydraulic motor 12 connected to the engine 10 to control the opening and closing of the regeneration passage 181. That is, the intermittent valve 150 is operated by the pilot signal pressure applied to supply the hydraulic oil from the accumulator 130 to the hydraulic motor 12 when the operation amount of the operation lever (not shown) exceeds the set value. It is switched in the downward direction (reference to the drawing) to open the regeneration passage 181. In this case, the high-pressure hydraulic oil stored in the accumulator 130 may be supplied to the hydraulic motor 12 connected to the engine 10 along the open regeneration passage 181, thereby driving the engine 10. Load generation can be reduced.
  • a solenoid valve may be used as the intermittent valve 150.
  • the hydraulic system 100 for a construction machine according to an embodiment of the present invention is installed on the upstream regeneration passage 181 of the accumulator 130 to detect the pressure sensor 160 for detecting the pressure of the regeneration passage 181. It may include.
  • the hydraulic system 100 for a construction machine according to an embodiment of the present invention is installed in the upstream regeneration passage 181 of the pressure sensor 160, and is set based on the pressure value detected by the pressure sensor 160. It may include a variable relief valve 170 for varying the pressure difference between the inlet C port and the outlet D port by the control signal value.
  • the hydraulic system 100 for a construction machine may maintain the hydraulic oil pressure supplied to the swing motor 110 when the upper swing body 20 swings so as not to exceed a set value.
  • the high-pressure hydraulic oil relief from the first flow path 185 and the second flow path 186 to the hydraulic tank 13 may be stored in the accumulator 130.
  • Figure 2 is a graph showing the pressure of the port A and port B of the swing motor during the loading operation using an excavator, the curve (a) of the graph shows the turning motor driving in the left direction, the curve (b) of the graph Shows the turning motor driving in the right direction.
  • the section 1 of FIG. 2 shows the pressure change when the upper swing body 20 is rotated in the forward direction.
  • the hydraulic pump 11 is connected to the A port of the swing motor 110 through the first flow path 185, and the B port of the swing motor 110 is connected to the hydraulic tank 13 through the second flow path 186. Connected. Accordingly, the hydraulic oil discharged from the hydraulic pump 11 is supplied to the A port of the swing motor 110 along the first flow path 185 via the flow control valve 120, thereby, the swing motor 110. Rotates in the forward direction. At this time, the hydraulic oil discharged from the B port of the swing motor 110 is returned to the hydraulic tank 13 via the second flow path 186 and the flow control valve 120.
  • section 2 of FIG. 2 shows the pressure change when the upper swing body 20 rotating in the forward direction is suddenly decelerated, that is, when the flow control valve 120 is switched to the neutral position.
  • the upper pivot 20 does not immediately stop rotating due to the large weight and rotational inertia. That is, when the flow control valve 120 is switched to the neutral position, the hydraulic oil discharged from the B port of the swing motor 110 due to the continuous operation of the swing motor 110 by the continuously rotating upper swing body 20.
  • Overload is generated in the second flow path 186 to which is moved.
  • the hydraulic fluid corresponding to the overload formed in the second flow path 186 passes through the fifth check valve 25 installed in the fourth flow path 188.
  • the high pressure hydraulic oil flowing into the fourth flow passage 188 between the fourth check valve 24 and the fifth check valve 25 from the second flow passage 186 through the fifth check valve 25 is passed through the regeneration passage. It is stored in the accumulator 130 installed at 181. At this time, due to the continuous operation of the swing motor 110, the hydraulic oil shortage required for the A port of the swing motor 110 is supplied through the boost device 140. That is, when the flow control valve 120 is switched to the neutral position, when the spool valve 144 is switched in the right direction (reference to the drawing) by the pilot signal pressure applied, the accumulator 130 may supply the first supply passage 182. It is connected to the first cylinder 141 through).
  • the working oil discharged from the accumulator 130 moves through the first supply passage 182 and is supplied to the first cylinder 141 via the spool valve 144.
  • the first cylinder 141 has a smaller area than the second cylinder 142 connected to the piston 143 through the piston 143, a high pressure is formed in the first cylinder 141, the second cylinder 142 In the low pressure corresponding to the pressure formed in the first cylinder 141 is formed.
  • the piston 143 is moved to the second cylinder 142 side by the high-pressure hydraulic oil pressure supplied to the first cylinder 141, and due to the movement of the piston 143, the second cylinder 142
  • the hydraulic oil filled in is pressurized and discharged from the second cylinder 142.
  • the hydraulic oil discharged from the second cylinder 142 flows into the third flow path 187 between the second check valve 22 and the third check valve 23 along the second supply passage 183. .
  • the hydraulic oil introduced into the third flow path 187 passes through the second check valve 22, and is then supplied to the A port of the swing motor 110 through the first flow path 185.
  • the first cylinder 141 is the hydraulic tank 13 Connected with Accordingly, the hydraulic oil supplied to the first cylinder 141 is drained to the hydraulic tank 13.
  • section 3 of FIG. 2 shows the pressure change when the upper swing body 20 is rotated in the reverse direction, and the flow control valve 120 is switched to the right direction (based on the drawing) by the applied pilot signal pressure.
  • the hydraulic pump 11 When the hydraulic pump 11 is connected to the B port of the swing motor 110 through the second flow path 186, the A port of the swing motor 110 is connected to the hydraulic tank 13 through the first flow path 185. Connected with Accordingly, the hydraulic oil discharged from the hydraulic pump 11 is supplied to the B port of the swing motor 110 along the second flow path 186 via the flow control valve 120, thereby, the swing motor 110. Will rotate in the reverse direction. At this time, the hydraulic oil discharged from the A port of the swing motor 110 is returned to the hydraulic tank 13 through the first flow path (185).
  • section 4 of FIG. 2 shows the pressure change when the upper swing body 20 turning in the reverse direction is sharply decelerated, that is, when the flow control valve 120 is switched to the neutral position.
  • the upper pivot 20 does not immediately stop rotating due to the large weight and rotational inertia. That is, when the flow control valve 120 is switched to the neutral position, the hydraulic oil discharged from the A port of the swing motor 110 due to the continuous operation of the swing motor 110 by the continuously rotating upper swing body 20. Overload is generated in the first flow path 185 to which is moved.
  • the hydraulic fluid corresponding to the overload formed in the first flow path 185 passes through the fourth check valve 24 installed in the fourth flow path 188.
  • the high pressure hydraulic oil introduced into the fourth flow path 188 between the fourth check valve 24 and the fifth check valve 25 from the first flow path 185 through the fourth check valve 24 is regenerated. It is stored in the accumulator 130 installed at 181. At this time, the hydraulic oil shortage required for the B port of the swing motor 110 is supplied through the boost device 140 due to the continuous operation of the swing motor 110. That is, when the flow control valve 120 is switched to the neutral position, when the spool valve 144 is switched in the right direction (reference to the drawing) by the pilot signal pressure applied, the accumulator 130 may supply the first supply passage 182. It is connected to the first cylinder 141 through).
  • the working oil discharged from the accumulator 130 moves through the first supply passage 182 and is supplied to the first cylinder 141 via the spool valve 144.
  • the first cylinder 141 has a smaller area than the second cylinder 142 connected to the piston 143 through the piston 143, a high pressure is formed in the first cylinder 141, the second cylinder 142 In the low pressure corresponding to the pressure formed in the first cylinder 141 is formed.
  • the piston 143 is moved to the second cylinder 142 side by the pressure of the hydraulic oil supplied to the first cylinder 141, due to the movement of the piston 143, to the second cylinder 142
  • the filled hydraulic oil is pressurized and discharged from the second cylinder 142.
  • the hydraulic oil discharged from the second cylinder 142 flows into the third flow path 187 between the second check valve 22 and the third check valve 23 along the second supply passage 183. .
  • the working oil introduced into the third flow path 187 passes through the third check valve 23 and is supplied to the B port of the swing motor 110 through the second flow path 186.
  • the first cylinder 141 is the hydraulic tank 13 Connected with Accordingly, the hydraulic oil supplied to the first cylinder 141 is drained to the hydraulic tank 13.
  • the hydraulic system 200 for a construction machine includes a hydraulic actuator, a flow control valve 120, an accumulator 130, and a boost device 240. Is formed.
  • the boost device 240 includes a first cylinder 241, a second cylinder 242, and a piston 243.
  • the first cylinder 241 is connected to the accumulator 130.
  • the second cylinder 242 is connected to the first cylinder 241.
  • the second cylinder 242 is formed with a relatively larger area than the first cylinder 241.
  • the piston 243 is formed in the form of connecting them between the first cylinder 241 and the second cylinder 242.
  • the piston 243 reciprocates between the first cylinder 241 and the second cylinder 242 by the hydraulic oil supplied to the first cylinder 241 or filled in the second cylinder 242.
  • the first cylinder (141 of FIG. 1) and the second cylinder (142 of FIG. 1) is formed in the form of a body, while in another embodiment of the present invention, the first cylinder ( The 241 and the second cylinder 242 are formed to be independent of each other.
  • the first cylinders 141 and 241 when the first cylinders 141 and 241 are formed with a relatively smaller area than the second cylinders 142 and 242, the actions and effects are the same, and thus the hydraulic system 100,
  • the first cylinders 141 and 241 and the second cylinders 142 and 242 may have various shapes or structures.

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  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Mining & Mineral Resources (AREA)
  • Civil Engineering (AREA)
  • Structural Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Mechanical Engineering (AREA)
  • Operation Control Of Excavators (AREA)
  • Fluid-Pressure Circuits (AREA)

Abstract

The present invention provides a hydraulic system for a construction machine, comprising: a hydraulic actuator connected to a hydraulic pump and driven by hydraulic oil, which is discharged and supplied from the hydraulic pump and fed back to a hydraulic tank; a flow control valve provided on the movement paths of the hydraulic oil, which moves between the hydraulic pump and the hydraulic actuator and between the hydraulic actuator and the hydraulic tank, so as to control the movement of the hydraulic oil; an accumulator provided on a regeneration path, which is branched from the movement path of the hydraulic oil directed toward the hydraulic tank, and storing the hydraulic oil introduced into the regeneration path when the flow control valve is switched to a neutral position; and a boost device connected to the accumulator and, when the flow control valve is switched to the neutral position such that the hydraulic oil discharged from the hydraulic pump cannot be supplied to the hydraulic actuator, using the hydraulic oil stored in the accumulator so as to supply, to the hydraulic actuator, the shortage of hydraulic oil required because of the continuous operation of the hydraulic actuator.

Description

건설기계용 유압 시스템Hydraulic Systems for Construction Machinery
본 발명은 건설기계용 유압 시스템에 관한 것으로서 더욱 상세하게는 어큐뮬레이터를 이용하여 부스트 기능을 구현할 수 있는 건설기계용 유압 시스템에 관한 것이다.The present invention relates to a hydraulic system for construction machinery, and more particularly, to a hydraulic system for construction machinery that can implement a boost function using an accumulator.
유압식 하이브리드 건설기계, 예컨대, 유압식 하이브리드 굴삭기의 경우에는 어큐뮬레이터를 이용하여, 선회 감속이나 붐 하강 시 유압 에너지를 저장한다.In the case of a hydraulic hybrid construction machine, for example, a hydraulic hybrid excavator, an accumulator is used to store hydraulic energy during turning deceleration or boom lowering.
종래의 유압식 하이브리드 굴삭기에서는 정방향으로 상부 선회체를 선회시키는 경우, 선회모터의 일측의 제1 포트로는 유압펌프로부터 토출되는 작동유가 공급되고, 선회모터의 타측의 제2 포트로부터는 작동유가 배출되어 유압탱크로 귀환된다. 또한, 역방향으로 상부 선회체를 선회시키는 경우, 선회모터의 제2 포트로는 유압펌프로부터 토출되는 작동유가 공급되고, 선회모터의 제1 포트로부터는 작동유가 배출되어 유압탱크로 귀환된다. 이때, 정방향으로 선회되는 상부 선회체를 급격하게 감속시키는 경우, 제1 포트로 유입되어 제2 포트로부터 배출되는 작동유는 어큐뮬레이터에 저장되고, 상부 선회체의 큰 중량 및 회전 관성력으로 인해 선회모터가 계속적으로 동작함에 따라, 유압펌프로부터의 작동유 공급이 중단된 제1 포트에는 유압탱크로부터 작동유가 흡입 및 보충된다. 또한, 역방향으로 선회되는 상부 선회체를 급격하게 감속시키는 경우, 제2 포트로 유입되어 제1 포트로부터 배출되는 작동유는 어큐뮬레이터에 저장되고, 마찬가지로, 유압펌프로부터의 작동유 공급이 중단된 제2 포트에는 유압탱크로부터 작동유가 흡입 및 보충된다.In the conventional hydraulic hybrid excavator, when the upper swing structure is rotated in the forward direction, the hydraulic oil discharged from the hydraulic pump is supplied to the first port on one side of the swing motor, and the hydraulic oil is discharged from the second port on the other side of the swing motor. Return to the hydraulic tank. Further, when the upper swing structure is turned in the reverse direction, the hydraulic oil discharged from the hydraulic pump is supplied to the second port of the swing motor, and the hydraulic oil is discharged from the first port of the swing motor to be returned to the hydraulic tank. At this time, in the case of rapidly decelerating the upper swinging body turning in the forward direction, the hydraulic oil flowing into the first port and discharged from the second port is stored in the accumulator, and the swinging motor continuously continues due to the large weight and rotational inertia of the upper swinging body. In operation, the hydraulic oil is sucked and replenished from the hydraulic tank to the first port where the hydraulic oil supply from the hydraulic pump is stopped. In addition, in the case of rapidly decelerating the upper swing body turning in the reverse direction, the hydraulic oil flowing into the second port and discharged from the first port is stored in the accumulator, and likewise, in the second port where the hydraulic oil supply from the hydraulic pump is stopped. Hydraulic fluid is sucked and refilled from the hydraulic tank.
하지만, 정방향으로 선회되는 상부 선회체를 급격하게 감속시키는 경우 제1 포트 및 역방향으로 선회되는 상부 선회체를 급격하게 감속시키는 경우 제2 포트에는 감속 시 작동유 공급이 중단됨에 따라 순간적으로 음압이 형성되므로, 유압탱크로부터의 작동유의 흡입이 원활하지 않은 문제가 있었다.However, when suddenly decelerating the upper swinging body turning in the forward direction, when the deceleration of the upper turning body turning in the reverse direction is sharply decelerated, the second port instantaneously generates a negative pressure as the supply of hydraulic oil stops. There was a problem that suction of hydraulic oil from the hydraulic tank was not smooth.
이를 해결하기 위해, 종래에는 선회 감속 시, 전기모터, 유압펌프 및 저압 어큐뮬레이터를 이용하여, 상부 선회체의 계속적인 회전으로 인해, 갑자기 요구되는 작동유를 선회모터에 공급하는 부스트 기능을 구현하였다.In order to solve this problem, in the related art, an electric motor, a hydraulic pump, and a low pressure accumulator are used to implement a boost function for supplying a suddenly required hydraulic fluid to the swing motor due to continuous rotation of the upper swing body.
본 발명은 상술한 바와 같은 종래기술의 문제점을 해결하기 위해 안출된 것으로서, 본 발명의 목적은 어큐뮬레이터를 이용하여 부스트 기능을 구현할 수 있는 건설기계용 유압 시스템을 제공하는 것이다.The present invention has been made to solve the problems of the prior art as described above, an object of the present invention to provide a hydraulic system for construction machinery that can implement a boost function using an accumulator.
이를 위해, 본 발명은, 유압펌프와 연결되고, 상기 유압펌프로부터 토출되어 공급되고 유압탱크로 귀환하는 작동유에 의해 구동되는 유압 액츄에이터; 상기 유압펌프와 상기 유압 액츄에이터 및 상기 유압 액츄에이터와 상기 유압탱크 사이를 이동하는 작동유의 이동 경로 상에 설치되어, 작동유의 이동을 제어하는 유량제어밸브; 상기 유압탱크로 향하는 작동유의 이동 경로로부터 분기되어 있는 재생통로에 설치되고, 상기 유량제어밸브가 중립위치로 전환되는 경우, 상기 재생통로로 유입되는 작동유를 저장하는 어큐뮬레이터; 및 상기 어큐뮬레이터와 연결되고, 상기 유량제어밸브가 중립위치로 전환되어, 상기 유압펌프로부터 토출되는 작동유가 상기 유압 액츄에이터로 공급되지 못하는 경우, 상기 어큐뮬레이터에 저장되어 있는 작동유를 이용하여, 상기 유압 액츄에이터의 계속 동작으로 인해 요구되는 작동유 부족분을 상기 유압 액츄에이터에 공급하는 부스트 장치를 포함하는 건설기계용 유압시스템을 제공한다.To this end, the present invention, a hydraulic actuator is connected to the hydraulic pump, driven by the operating oil discharged from the hydraulic pump supplied to the hydraulic tank; A flow control valve installed on the hydraulic pump and the hydraulic actuator and a moving path of the hydraulic oil moving between the hydraulic actuator and the hydraulic tank to control the movement of the hydraulic oil; An accumulator installed in the regeneration passage branched from the movement path of the hydraulic oil directed to the hydraulic tank and storing the hydraulic oil flowing into the regeneration passage when the flow control valve is switched to the neutral position; And hydraulic fluid stored in the accumulator, when the hydraulic fluid discharged from the hydraulic pump is not supplied to the hydraulic actuator, when the flow control valve is switched to the neutral position and is connected to the accumulator. Provided is a hydraulic system for a construction machine, comprising a boost device for supplying a hydraulic oil shortage required by the continuous operation to the hydraulic actuator.
여기서, 상기 부스트 장치는, 상기 어큐뮬레이터와 연결되는 제1 실린더, 상기 제1 실린더와 연결되고 상기 제1 실린더보다 상대적으로 큰 면적으로 형성되며 상기 제1 실린더에 상기 어큐뮬레이터로부터 작동유가 공급되는 경우 내부에 충전되어 있는 작동유를 상기 유압 액츄에이터 측으로 배출하는 제2 실린더, 및 상기 제1 실린더와 상기 제2 실린더를 연결하는 형태로 상기 제1 실린더와 상기 제2 실린더 사이에 설치되어, 상기 제1 실린더에 공급되거나 상기 제2 실린더에 충전되는 작동유에 의해 상기 제1 실린더와 상기 제2 실린더 사이를 왕복 운동하는 피스톤을 포함할 수 있다.Here, the boost device, the first cylinder is connected to the accumulator, the first cylinder is connected to the first cylinder is formed with a relatively larger area than the first cylinder when the hydraulic fluid is supplied from the accumulator therein A second cylinder for discharging the filled hydraulic oil to the hydraulic actuator side, and is provided between the first cylinder and the second cylinder in a form of connecting the first cylinder and the second cylinder, and is supplied to the first cylinder; Or a piston reciprocating between the first cylinder and the second cylinder by the hydraulic oil filled in the second cylinder.
상기 제1 실린더와 상기 제2 실린더는 하나의 바디를 이루는 형태로 형성되거나 서로 독립적인 형태로 형성될 수 있다.The first cylinder and the second cylinder may be formed in the form of one body or may be formed in an independent form.
상기 부스트 장치는 상기 어큐뮬레이터와 상기 제1 실린더 사이를 연결하는 제1 공급통로에 설치되어 상기 어큐뮬레이터로부터 상기 제1 실린더로의 작동유 이동 및 상기 제1 실린더로부터 상기 유압탱크로의 작동유 이동을 제어하는 스풀밸브를 더 포함할 수 있다.The boost device is installed in a first supply passage connecting between the accumulator and the first cylinder, the spool controlling hydraulic oil movement from the accumulator to the first cylinder and hydraulic oil movement from the first cylinder to the hydraulic tank. The valve may further include.
또한, 상기 제2 실린더는 제2 공급통로를 통해 상기 유압 액츄에이터와 연결될 수 있다.In addition, the second cylinder may be connected to the hydraulic actuator through a second supply passage.
상기 제2 실린더는 제2 공급통로에 접속되는 제3 공급통로를 통해 MCV 리턴 유로와 연결될 수 있다.The second cylinder may be connected to the MCV return passage through a third supply passage connected to the second supply passage.
상기 제3 공급통로는 상기 MCV 리턴 유로에서 상기 제2 실린더 측으로 일 방향으로의 작동유 이동을 허용하는 제1 체크밸브를 포함할 수 있다.The third supply passage may include a first check valve to allow a hydraulic oil movement in one direction from the MCV return flow passage to the second cylinder side.
상기 제1 실린더로부터 상기 유압탱크로 작동유 이동이 가능하도록 상기 스풀밸브가 절환되는 경우, 상기 MCV 리턴 유로를 이동하는 작동유가 압력 차에 따라 상기 제2 실린더에 자동 충전될 수 있다.When the spool valve is switched so that the hydraulic oil can be moved from the first cylinder to the hydraulic tank, the hydraulic oil for moving the MCV return flow path may be automatically filled in the second cylinder according to the pressure difference.
또한, 상기 유압 액츄에이터는 선회모터 또는 어태치먼트용 유압 실린더일 수 있다.In addition, the hydraulic actuator may be a swing motor or a hydraulic cylinder for attachment.
상기 유압펌프와 상기 유압 액츄에이터를 연결시키는 제1 유로 및 제2 유로를 더 포함할 수 있다.It may further include a first flow path and a second flow path for connecting the hydraulic pump and the hydraulic actuator.
상기 제1 유로 및 상기 제2 유로에 양단이 분기 접속되고, 상기 부스트 장치로부터 상기 제1 유로 및 상기 제2 유로 측으로 일 방향으로의 작동유 이동을 각각 허용하는 제2 및 제3 체크밸브가 각각 설치되는 제3 유로, 및 상기 제3 유로와 병렬형을 이루는 형태로 상기 제1 유로 및 상기 제2 유로의 상류측에 양단이 분기 접속되고, 상기 제1 유로 또는 상기 제2 유로에서 상기 유압탱크 측으로 일 방향으로의 작동유 이동을 각각 허용하는 제4 및 제5 체크밸브가 각각 설치되는 제4 유로를 더 포함할 수 있다.Both ends are branch-connected to the first flow path and the second flow path, and second and third check valves are respectively provided to allow movement of hydraulic fluid in one direction from the boost device to the first flow path and the second flow path. A third flow path being formed in parallel with the third flow path, and both ends are connected to an upstream side of the first flow path and the second flow path, and the first flow path or the second flow path is connected to the hydraulic tank. The apparatus may further include a fourth flow path in which fourth and fifth check valves respectively allowing movement of the hydraulic fluid in one direction are installed.
상기 어큐뮬레이터와 엔진에 연결되어 있는 유압모터 사이의 상기 재생통로에 설치되어 상기 재생통로의 개폐를 제어하는 단속밸브를 더 포함할 수 있다.It may further include an intermittent valve installed in the regeneration passage between the accumulator and the hydraulic motor connected to the engine to control the opening and closing of the regeneration passage.
또한, 상기 어큐뮬레이터의 상류측 상기 재생통로에 설치되고, 상기 재생통로의 압력을 검출하는 압력센서를 더 포함할 수 있다.The apparatus may further include a pressure sensor installed in an upstream side of the accumulator and detecting a pressure of the regenerative passage.
상기 압력센서의 상류측 상기 재생통로에 설치되고, 상기 압력센서에 의해 검출되는 압력 값을 토대로 설정된 제어신호 값에 의해 입구측 포트와 출구측 포트 간의 압력 차를 가변 조정하는 가변 릴리프밸브를 더 포함할 수 있다.And a variable relief valve installed in the regeneration passage upstream of the pressure sensor and variably adjusting a pressure difference between the inlet port and the outlet port by a control signal value set based on the pressure value detected by the pressure sensor. can do.
본 발명에 따르면, 어큐뮬레이터를 이용하여 부스트 기능을 구현함으로써, 예컨대, 상부 선회체의 선회를 급격히 감소시키는 경우, 상부 선회체의 큰 중량 및 회전 관성력으로 인해 선회모터가 계속적으로 동작함에 따라, 갑자기 요구되는 작동유를 별도의 복잡한 전기적 장치 없이도 순간적으로 선회모터에 공급할 수 있고, 이를 통해, 장치 안정성을 확보할 수 있다.According to the present invention, by implementing a boost function using an accumulator, for example, when sharply reducing the turning of the upper turning body, as the turning motor continues to operate due to the large weight of the upper turning body and the rotational inertia, suddenly required The operating oil can be supplied to the turning motor instantaneously without a separate complicated electrical device, thereby ensuring the stability of the device.
또한, 본 발명에 따르면, 면적이 다른 두 개의 실린더를 통해 부스트 기능을 구현함으로써, 부스트 장치의 구성 및 비용을 최소화할 수 있다.In addition, according to the present invention, by implementing the boost function through two cylinders of different areas, it is possible to minimize the configuration and cost of the boost device.
도 1은 본 발명의 일 실시 예에 따른 건설기계용 유압 시스템을 나타낸 유압 회로도이다.1 is a hydraulic circuit diagram showing a hydraulic system for a construction machine according to an embodiment of the present invention.
도 2는 굴삭기를 이용하여 상차 작업 시 선회모터의 입구측 압력 변화를 나타낸 그래프이다.Figure 2 is a graph showing the change in pressure of the inlet side of the swing motor during loading operation using an excavator.
도 3은 본 발명의 다른 실시 예에 따른 건설기계용 유압 시스템을 나타낸 유압 회로도이다.3 is a hydraulic circuit diagram showing a hydraulic system for a construction machine according to another embodiment of the present invention.
이하에서는 첨부된 도면들을 참조하여 본 발명의 실시 예에 따른 건설기계용 유압 시스템에 대해 상세히 설명한다.Hereinafter, with reference to the accompanying drawings will be described in detail for the hydraulic system for construction machinery according to an embodiment of the present invention.
아울러, 본 발명을 설명함에 있어서, 관련된 공지 기능 혹은 구성에 대한 구체적인 설명이 본 발명의 요지를 불필요하게 흐릴 수 있다고 판단된 경우 그 상세한 설명은 생략한다.In addition, in describing the present invention, when it is determined that a detailed description of a related known function or configuration may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted.
도 1에 도시한 바와 같이, 본 발명의 일 실시 예에 따른 건설기계용 유압 시스템(100)은 유압을 통해 예컨대, 굴삭기와 같은 건설기계의 동작을 제어하는 시스템으로, 유압 액츄에이터, 유량제어밸브(120), 어큐뮬레이터(130) 및 부스트 장치(140)를 포함하여 형성된다. 이때, 본 발명의 일 실시 예에서는 유압 액츄에이터로 선회모터(110)를 예시하였으나, 이에 한정되는 것은 아니다. 즉, 유압 액츄에이터는 예컨대, 굴삭기의 붐, 아암, 버켓으로 이루어지는 어태치먼트용 유압 실린더일 수도 있다.As shown in FIG. 1, the hydraulic system 100 for a construction machine according to an exemplary embodiment of the present invention is a system for controlling the operation of a construction machine such as an excavator through hydraulic pressure, and includes a hydraulic actuator and a flow control valve. 120, an accumulator 130, and a boost device 140. At this time, in one embodiment of the present invention, the swing motor 110 is illustrated as a hydraulic actuator, but is not limited thereto. That is, the hydraulic actuator may be, for example, an attachment hydraulic cylinder including an boom, an arm and a bucket of the excavator.
본 발명의 일 실시 예에서 유압 액츄에이터로 사용되는 선회모터(110)는 하부 주행체(미도시) 상에 탑재되어 있는 상부 선회체(20)를 정방향 또는 역방향으로 선회시키는 모터이다. 이러한 선회모터(110)는 유압펌프(11)와 연결된다. 이에 따라, 선회모터(110)는 유압펌프(11)로부터 토출되어 A포트로 공급되고 B포트로부터 배출되어 유압탱크(13)로 귀환하는 작동유에 의해 구동된다. 이때, 유압펌프(11)는 가변용량형 유압펌프로, 엔진(10)에 연결된다. 또한, 엔진(10)에는 유압모터(12)가 연결된다.In one embodiment of the present invention, the swing motor 110 used as the hydraulic actuator is a motor for turning the upper swing body 20 mounted on the lower traveling body (not shown) in the forward or reverse direction. The swing motor 110 is connected to the hydraulic pump (11). Accordingly, the swing motor 110 is driven by the hydraulic oil discharged from the hydraulic pump 11 and supplied to the A port, discharged from the B port and returned to the hydraulic tank 13. At this time, the hydraulic pump 11 is a variable displacement hydraulic pump, it is connected to the engine (10). In addition, the hydraulic motor 12 is connected to the engine 10.
유량제어밸브(120)는 작동유의 이동을 제어하는 밸브이다. 이를 위해, 유량제어밸브(120)는 유압펌프(11)와 선회모터(110) 및 선회모터(110)와 유압탱크(13) 사이를 이동하는 작동유의 이동 경로 상에 설치된다. 구체적으로, 유량제어밸브(120)는 유압펌프(11)와 선회모터(110)를 연결시키는 제1 유로(185) 및 제2 유로(186)에 설치된다. 이러한 유량제어밸브(120)는 길이방향 일측에 형성되어 있는 포트로 인가되는 파일럿 신호압에 의해 절환되어, 유압펌프(11)로부터 토출되는 작동유가 제1 유로(185)를 통해 선회모터(110)의 A포트로 공급되고 선회모터(110)의 B포트로부터 배출되어 제2 유로(186)를 통해 유압탱크(13)로 귀환 가능하게 한다. 이를 통해, 선회모터(110)는 정방향으로 회전하고, 이에 따라, 상부 선회체(20)는 정방향으로의 선회 동작을 하게 된다. 반대로, 유량제어밸브(120)는 길이방향 타측에 형성되어 있는 포트로 인가되는 파일럿 신호압에 의해 절환되어, 작동유가 제2 유로(186)를 통해 선회모터(110)의 B포트로 공급되고 선회모터(110)의 A포트로부터 배출되어 제1 유로(185)를 통해 유압탱크(13)로 귀환 가능하게 한다. 이를 통해, 선회모터(110)는 역방향으로 회전하고, 이에 따라, 상부 선회체(20)는 역방향으로의 선회 동작을 하게 된다. 또한, 유량제어밸브(120)는 외부로부터 인가되는 파일럿 신호압에 의해 중립으로 전환되어, 유압펌프(11)로부터 선회모터(110)로의 작동유 공급을 차단한다. 이를 통해, 선회모터(110)의 회전 및 상부 선회체(20)의 선회 동작은 중지된다. 이와 같이, 유량제어밸브(120)는 선회모터(110)의 회전, 정지 및 방향 전환을 제어한다. Flow control valve 120 is a valve for controlling the movement of the working oil. To this end, the flow control valve 120 is installed on the hydraulic pump 11 and the swinging motor 110 and the movement path of the hydraulic oil moving between the swinging motor 110 and the hydraulic tank (13). Specifically, the flow control valve 120 is installed in the first flow path 185 and the second flow path 186 connecting the hydraulic pump 11 and the swing motor 110. The flow control valve 120 is switched by the pilot signal pressure applied to the port formed on one side in the longitudinal direction, the hydraulic oil discharged from the hydraulic pump 11 is pivoting motor 110 through the first flow path (185) It is supplied to the A port of the and is discharged from the B port of the swing motor 110 to be able to return to the hydraulic tank 13 through the second flow path (186). As a result, the turning motor 110 rotates in the forward direction, and accordingly, the upper swinging body 20 performs the turning operation in the forward direction. On the contrary, the flow control valve 120 is switched by the pilot signal pressure applied to the port formed on the other side in the longitudinal direction, so that the hydraulic oil is supplied to the B port of the swing motor 110 through the second flow path 186 and swings. It is discharged from the A port of the motor 110 to enable the return to the hydraulic tank 13 through the first flow path (185). As a result, the turning motor 110 rotates in the reverse direction, and accordingly, the upper swinging body 20 performs the turning operation in the reverse direction. In addition, the flow control valve 120 is switched to neutral by the pilot signal pressure applied from the outside, and shuts off the supply of hydraulic oil from the hydraulic pump 11 to the swing motor 110. Through this, the rotation of the swing motor 110 and the swing operation of the upper swing body 20 is stopped. As such, the flow control valve 120 controls the rotation, stop and direction change of the swing motor 110.
한편, 본 발명의 일 실시 예에 따른 건설기계의 유압 시스템(100)은 제3 유로(187)를 포함할 수 있다. 제3 유로(187)는 제1 유로(185) 및 제2 유로(186)에 양단이 분기 접속된다. 이러한 제3 유로(187)에는 부스트 장치(140)로부터 제1 유로(185) 측으로 일 방향으로의 작동유 이동을 허용하는 제2 체크밸브(22)와, 부스트 장치(140)로부터 제2 유로(186) 측으로 일 방향으로의 작동유 이동을 허용하는 제3 체크밸브(23)가 설치될 수 있다. 또한, 본 발명의 일 실시 예에 따른 건설기계의 유압 시스템(100)은 제4 유로(188)를 포함할 수 있다. 제4 유로(188)는 제3 유로(187)와 병렬형을 이루는 형태로 제1 유로(185) 및 제2 유로(186)의 상류측에 양단이 분기 접속된다. 이러한 제4 유로(188)에는 제1 유로(185)에서 어큐뮬레이터(130) 측으로 일 방향으로의 작동유 이동을 허용하는 제4 체크밸브(24)와, 제2 유로(186)에서 어큐뮬레이터(130) 측으로 일 방향으로의 작동유 이동을 허용하는 제5 체크밸브(25)가 설치될 수 있다.On the other hand, the hydraulic system 100 of a construction machine according to an embodiment of the present invention may include a third flow path (187). Both ends of the third flow path 187 are connected to the first flow path 185 and the second flow path 186. The third flow path 187 includes a second check valve 22 that allows the hydraulic fluid to move in one direction from the boost device 140 to the first flow path 185, and the second flow path 186 from the boost device 140. A third check valve 23 may be installed to allow the hydraulic oil to move in one direction to the side. In addition, the hydraulic system 100 of the construction machine according to an embodiment of the present invention may include a fourth flow path (188). The fourth flow path 188 is parallel to the third flow path 187, and both ends thereof are branched to the upstream side of the first flow path 185 and the second flow path 186. The fourth flow path 188 includes a fourth check valve 24 that allows the hydraulic fluid to move in one direction from the first flow path 185 to the accumulator 130, and from the second flow path 186 to the accumulator 130. A fifth check valve 25 may be installed to allow the hydraulic oil to move in one direction.
어큐뮬레이터(130)는 유압탱크(13)로 향하는 작동유의 이동 경로로부터 분기되어 있는 재생통로(181)에 설치된다. 구체적으로, 어큐뮬레이터(130)는 제4 체크밸브(24)와 제5 체크밸브(25) 사이의 제4 유로(188)에 일단이 접속되고 어시스트용 모터인 유압모터(12)에 타단이 접속되어 있는 재생통로(181)에 설치된다. 이러한 어큐뮬레이터(130)는 유량제어밸브(120)가 중립위치로 전환되는 경우, 제1 유로(185) 또는 제2 유로(186)에 발생되는 과부하에 따라 재생통로(181)로 유입되는 작동유를 저장한다.The accumulator 130 is installed in the regeneration passage 181 branched from the movement path of the hydraulic oil toward the hydraulic tank 13. Specifically, the accumulator 130 has one end connected to the fourth flow path 188 between the fourth check valve 24 and the fifth check valve 25 and the other end connected to the hydraulic motor 12 which is an assist motor. It is installed in the regeneration passage 181. When the flow control valve 120 is switched to the neutral position, the accumulator 130 stores the hydraulic oil flowing into the regeneration passage 181 according to the overload generated in the first flow passage 185 or the second flow passage 186. do.
엔진(10)의 구동 회전수가 설정된 회전수 값에 미치지 못할 경우, 어큐뮬레이터(130)에 저장되어 있는 작동유는 유압모터(12)에 공급될 수 있다. 또한, 어큐뮬레이터(130)의 압력이 일정 압력 이상일 경우, 어큐뮬레이터(130)에 저장되어 있는 작동유는 유압모터(12)에 공급될 수 있고, 이를 통해, 엔진(10)의 부하를 줄일 수 있다. 그리고 본 발명의 일 실시 예에서는 상부 선회체(20)의 선회 감속 시 어큐뮬레이터(130)에 저장되어 있는 작동유가 부스트 장치(140)에 공급될 수 있는데, 이에 대해서는 하기에서 보다 상세히 설명하기로 한다.When the driving speed of the engine 10 does not reach the set speed value, the hydraulic oil stored in the accumulator 130 may be supplied to the hydraulic motor 12. In addition, when the pressure of the accumulator 130 is greater than or equal to a predetermined pressure, the hydraulic oil stored in the accumulator 130 may be supplied to the hydraulic motor 12, thereby reducing the load of the engine 10. In addition, in an embodiment of the present invention, the hydraulic oil stored in the accumulator 130 may be supplied to the boost device 140 when the upper swing body 20 decelerates turning, which will be described in more detail below.
부스트 장치(140)는 어큐뮬레이터(130)를 이용하여 부스트(boost) 기능을 구현하는 장치로, 어큐뮬레이터(130)와 연결된다. 즉, 부스트 장치(140)는 상부 선회체(20)의 선회 감속을 위해 유량제어밸브(120)가 중립위치로 전환되어 유압펌프(11)로부터 토출되는 작동유가 선회모터(110)로 공급되지 못하는 경우, 어큐뮬레이터(130)에 저장되어 있는 작동유를 이용하여, 상부 선회체(20)의 큰 중량 및 회전 관성력에 의해 발생되는 선회모터(110)의 계속 동작으로 인해 요구되는 작동유 부족분을 선회모터(110)에 공급한다.The boost device 140 is a device that implements a boost function using the accumulator 130 and is connected to the accumulator 130. That is, in the boost device 140, the flow control valve 120 is switched to the neutral position to reduce the turning speed of the upper swing body 20 so that the hydraulic oil discharged from the hydraulic pump 11 may not be supplied to the swing motor 110. In this case, by using the hydraulic oil stored in the accumulator 130, the hydraulic oil shortage required by the continuous operation of the swing motor 110 generated by the large weight of the upper swing body 20 and the rotational inertia force is rotated motor 110 Supplies).
이를 위해, 부스트 장치(140)는 제1 실린더(141), 제2 실린더(142) 및 피스톤(143)을 포함하여 형성될 수 있다. 제1 실린더(141)는 어큐뮬레이터(130)와 연결된다. 또한, 제2 실린더(142)는 제1 실린더(141)와 연결된다. 이때, 제2 실린더(142)는 제1 실린더(141)보다 상대적으로 큰 면적으로 형성된다. 이러한 제2 실린더(142)는 제1 실린더(141)에 어큐뮬레이터(130)로부터 작동유가 공급되는 경우, 제1 실린더(141)에 공급되는 고압의 작동유에 의해, 내부에 충전되어 있는 작동유를 선회모터(110) 측으로 배출 혹은 공급한다. 이를 통해, 상부 선회체(20)의 큰 중량 및 회전 관성력으로 인해 계속 동작하는 선회모터(110)가 안정적으로 구동할 수 있게 된다. 피스톤(143)은 하나의 바디를 이루는 형태로 형성되어 있는 제1 실린더(141)와 제2 실린더(142) 사이에서 이들 공간을 구획하는 형태로 형성된다. 이러한 피스톤(143)은 제1 실린더(141)에 공급되거나 제2 실린더(142)에 충전되는 작동유에 의해 제1 실린더(141)와 제2 실린더(142) 사이를 왕복 운동한다.To this end, the boost device 140 may include a first cylinder 141, a second cylinder 142, and a piston 143. The first cylinder 141 is connected to the accumulator 130. In addition, the second cylinder 142 is connected to the first cylinder 141. In this case, the second cylinder 142 is formed with a relatively larger area than the first cylinder 141. When the hydraulic oil is supplied from the accumulator 130 to the first cylinder 141, the second cylinder 142 rotates the hydraulic oil filled therein by the high pressure hydraulic oil supplied to the first cylinder 141. Discharge or supply to the (110) side. Through this, the turning motor 110 continuously operates due to the large weight and the rotational inertia force of the upper swinging body 20 can be stably driven. The piston 143 is formed to partition these spaces between the first cylinder 141 and the second cylinder 142, which are formed in one body. The piston 143 reciprocates between the first cylinder 141 and the second cylinder 142 by the hydraulic oil supplied to the first cylinder 141 or filled in the second cylinder 142.
또한, 부스트 장치(140)는 스풀밸브(144)를 더 포함한다. 스풀밸브(144)는 어큐뮬레이터(130)와 제1 실린더(141) 사이를 연결하는 제1 공급통로(182)에 설치된다. 이러한 스풀밸브(144)는 어큐뮬레이터(130)로부터 제1 실린더(141)로의 작동유의 이동을 제어하고, 제1 실린더(141)로부터 유압탱크(13)로의 작동유의 이동을 제어한다.In addition, the boost device 140 further includes a spool valve 144. The spool valve 144 is installed in the first supply passage 182 connecting between the accumulator 130 and the first cylinder 141. The spool valve 144 controls the movement of the hydraulic oil from the accumulator 130 to the first cylinder 141, and controls the movement of the hydraulic oil from the first cylinder 141 to the hydraulic tank 13.
본 발명의 일 실시 예에서, 제2 실린더(142)는 제2 공급통로(183)를 통해 선회모터(110)와 연결된다. 또한, 제2 실린더(142)는 제2 공급통로(183)에 접속되는 제3 공급통로(184)를 통해 MCV(main control valve) 리턴 유로(15)와 연결된다. 이때, 제3 공급통로(184)는 MCV 리턴 유로(15)에서 제2 실린더(142) 측으로 일방향으로의 작동유 이동을 허용하기 위해 설치되는 제1 체크밸브(21)를 포함할 수 있다. 여기서, 제1 실린더(141)로부터 유압탱크(13)로 작동유의 이동이 가능하도록 스풀밸브(144)가 절환되는 경우, 제1 실린더(141)에는 압력이 형성되지 않고 MCV 리턴 유로(15)의 압력은 항상 3~7bar 정도로 유지되기 때문에, MCV 리턴 유로(15)를 이동하는 작동유는 압력 차에 따라 제2 실린더(142)로 자동 충전된다.In one embodiment of the present invention, the second cylinder 142 is connected to the swing motor 110 through the second supply passage (183). In addition, the second cylinder 142 is connected to the main control valve (MCV) return passage 15 through a third supply passage 184 connected to the second supply passage 183. In this case, the third supply passage 184 may include a first check valve 21 installed to allow movement of the hydraulic oil in one direction from the MCV return flow passage 15 to the second cylinder 142. Here, when the spool valve 144 is switched so that the hydraulic oil can be moved from the first cylinder 141 to the hydraulic tank 13, the pressure is not formed in the first cylinder 141 and the MCV return flow path 15 of the Since the pressure is always maintained at about 3-7 bar, the hydraulic fluid moving the MCV return flow path 15 is automatically filled in the second cylinder 142 according to the pressure difference.
한편, 본 발명의 일 실시 예에 따른 건설기계용 유압 시스템(100)은 단속밸브(150)를 포함할 수 있다. 단속밸브(150)는 어큐뮬레이터(130)와 엔진(10)에 연결되어 있는 유압모터(12) 사이의 재생통로(181)에 설치되어 재생통로(181)의 개폐를 제어한다. 즉, 단속밸브(150)는 조작레버(미도시)의 조작량이 설정 값을 초과한 경우, 어큐뮬레이터(130)로부터 유압모터(12)로 작동유를 공급할 수 있도록 하기 위해, 인가되는 파일럿 신호압에 의해 하측 방향(도면 기준)으로 절환되어 재생통로(181)를 개방시킨다. 이렇게 되면, 개방된 재생통로(181)를 따라 어큐뮬레이터(130)에 저장된 고압의 작동유를 엔진(10)에 연결되어 있는 유압모터(12)에 공급시킬 수 있고, 이를 통해, 엔진(10) 구동 시 부하 발생량을 줄일 수 있게 된다. 이러한 단속밸브(150)로는 솔레노이드밸브가 사용될 수 있다. 또한, 본 발명의 일 실시 예에 따른 건설기계용 유압 시스템(100)은 어큐뮬레이터(130)의 상류측 재생통로(181)에 설치되어 재생통로(181)의 압력을 검출하는 압력센서(160)를 포함할 수 있다. 또한, 본 발명의 일 실시 예에 따른 건설기계용 유압 시스템(100)은 압력센서(160)의 상류측 재생통로(181)에 설치되어, 압력센서(160)에 의해 검출되는 압력 값을 토대로 설정된 제어신호 값에 의해 입구측 C포트와 출구측 D포트 간의 압력 차를 가변 조정하는 가변 릴리프밸브(170)를 포함할 수 있다. 이를 통해, 본 발명의 일 실시 예에 따른 건설기계용 유압 시스템(100)은 상부 선회체(20)의 선회 시 선회모터(110)에 공급되는 작동유 압력이 설정 값을 초과하지 않도록 유지할 수 있고, 제1 유로(185) 및 제2 유로(186)로부터 유압탱크(13)로 릴리프되는 고압의 작동유를 어큐뮬레이터(130)에 저장할 수 있다.On the other hand, the hydraulic system 100 for construction machinery according to an embodiment of the present invention may include an intermittent valve 150. The intermittent valve 150 is installed in the regeneration passage 181 between the accumulator 130 and the hydraulic motor 12 connected to the engine 10 to control the opening and closing of the regeneration passage 181. That is, the intermittent valve 150 is operated by the pilot signal pressure applied to supply the hydraulic oil from the accumulator 130 to the hydraulic motor 12 when the operation amount of the operation lever (not shown) exceeds the set value. It is switched in the downward direction (reference to the drawing) to open the regeneration passage 181. In this case, the high-pressure hydraulic oil stored in the accumulator 130 may be supplied to the hydraulic motor 12 connected to the engine 10 along the open regeneration passage 181, thereby driving the engine 10. Load generation can be reduced. A solenoid valve may be used as the intermittent valve 150. In addition, the hydraulic system 100 for a construction machine according to an embodiment of the present invention is installed on the upstream regeneration passage 181 of the accumulator 130 to detect the pressure sensor 160 for detecting the pressure of the regeneration passage 181. It may include. In addition, the hydraulic system 100 for a construction machine according to an embodiment of the present invention is installed in the upstream regeneration passage 181 of the pressure sensor 160, and is set based on the pressure value detected by the pressure sensor 160. It may include a variable relief valve 170 for varying the pressure difference between the inlet C port and the outlet D port by the control signal value. Through this, the hydraulic system 100 for a construction machine according to an embodiment of the present invention may maintain the hydraulic oil pressure supplied to the swing motor 110 when the upper swing body 20 swings so as not to exceed a set value. The high-pressure hydraulic oil relief from the first flow path 185 and the second flow path 186 to the hydraulic tank 13 may be stored in the accumulator 130.
이하, 본 발명의 일 실시 예에 따른 건설기계용 유압 시스템의 작동에 대하여 도 1 및 도 2를 참조하여 설명하기로 한다. 여기서, 도 2는 굴삭기를 이용한 상차 작업 시 선회모터의 A포트와 B포트의 압력을 나타낸 그래프로, 그래프의 곡선(a)는 좌측방향으로의 선회모터 구동을 나타낸 것이고, 그래프의 곡선(b)는 우측방향으로의 선회모터 구동을 나타낸 것이다.Hereinafter, the operation of the hydraulic system for construction machinery according to an embodiment of the present invention will be described with reference to FIGS. 1 and 2. Here, Figure 2 is a graph showing the pressure of the port A and port B of the swing motor during the loading operation using an excavator, the curve (a) of the graph shows the turning motor driving in the left direction, the curve (b) of the graph Shows the turning motor driving in the right direction.
먼저, 도 2의 구간1은 상부 선회체(20)가 정방향으로 선회되는 경우의 압력 변화를 나타낸 것으로, 인가되는 파일럿 신호압에 의해 유량제어밸브(120)가 좌측방향(도면 기준)으로 절환되면, 유압펌프(11)는 제1 유로(185)를 통해 선회모터(110)의 A포트에 연결되고, 선회모터(110)의 B포트는 제2 유로(186)를 통해 유압탱크(13)와 연결된다. 이에 따라, 유압펌프(11)로부터 토출되는 작동유는 유량제어밸브(120)를 경유하여 제1 유로(185)를 따라 선회모터(110)의 A포트에 공급되고, 이로 인해, 선회모터(110)는 정방향으로 회전하게 된다. 이때, 선회모터(110)의 B포트로부터 배출되는 작동유는 제2 유로(186)와 유량제어밸브(120)를 경유하여 유압탱크(13)로 귀환된다.First, the section 1 of FIG. 2 shows the pressure change when the upper swing body 20 is rotated in the forward direction. When the flow control valve 120 is switched to the left direction (based on the drawing) by the applied pilot signal pressure, The hydraulic pump 11 is connected to the A port of the swing motor 110 through the first flow path 185, and the B port of the swing motor 110 is connected to the hydraulic tank 13 through the second flow path 186. Connected. Accordingly, the hydraulic oil discharged from the hydraulic pump 11 is supplied to the A port of the swing motor 110 along the first flow path 185 via the flow control valve 120, thereby, the swing motor 110. Rotates in the forward direction. At this time, the hydraulic oil discharged from the B port of the swing motor 110 is returned to the hydraulic tank 13 via the second flow path 186 and the flow control valve 120.
다음으로, 도 2의 구간2는 정방향으로 회전하고 있는 상부 선회체(20)를 급격하게 감속시키는 경우, 즉, 유량제어밸브(120)를 중립위치로 전환시킨 경우 압력 변화를 나타낸 것으로, 이 경우, 상부 선회체(20)는 큰 중량 및 회전 관성력으로 인해 곧바로 회전을 멈추지 못한다. 즉, 유량제어밸브(120)를 중립위치로 전환시킨 경우, 계속적으로 회전하는 상부 선회체(20)에 의한 선회모터(110)의 계속 동작으로 인해 선회모터(110)의 B포트로부터 배출되는 작동유가 이동하는 제2 유로(186)에는 과부하가 발생된다. 제2 유로(186)에 형성되는 과부하에 해당되는 작동유는 제4 유로(188)에 설치되어 있는 제5 체크밸브(25)를 통과한다. 그리고 제2 유로(186)로부터 제5 체크밸브(25)를 통해, 제4 체크밸브(24) 및 제5 체크밸브(25) 사이의 제4 유로(188)에 유입된 고압의 작동유는 재생통로(181)에 설치되어 있는 어큐뮬레이터(130)에 저장된다. 이때, 선회모터(110)의 계속적인 동작으로 인해 선회모터(110)의 A포트에 요구되는 작동유 부족분은 부스트 장치(140)를 통해 공급된다. 즉, 유량제어밸브(120)가 중립위치로 전환된 경우, 인가되는 파일럿 신호압에 의해 스풀밸브(144)가 우측방향(도면 기준)으로 절환되면, 어큐뮬레이터(130)는 제1 공급통로(182)를 통해 제1 실린더(141)에 연결된다. 이에 따라, 어큐뮬레이터(130)로부터 배출되는 작동유는 제1 공급통로(182)를 통해 이동하다가 스풀밸브(144)를 경유하여 제1 실린더(141)에 공급된다. 이때, 제1 실린더(141)는 이와 피스톤(143)을 매개로 연결되어 있는 제2 실린더(142)보다 면적이 작으므로, 제1 실린더(141)에는 고압이 형성되고, 제2 실린더(142)에는 제1 실린더(141)에 형성된 압력에 상응하는 저압이 형성된다. 이에 따라, 피스톤(143)은 제1 실린더(141)에 공급되는 고압의 작동유 압력에 밀려 제2 실린더(142) 측으로 이동하게 되고, 이러한 피스톤(143)의 이동으로 인해, 제2 실린더(142)에 충전되어 있는 작동유는 가압되어, 제2 실린더(142)로부터 배출된다. 이와 같이, 제2 실린더(142)로부터 배출되는 작동유는 제2 공급통로(183)를 따라, 제2 체크밸브(22) 및 제3 체크밸브(23) 사이의 제3 유로(187)에 유입된다. 그리고 제3 유로(187)에 유입된 작동유는 제2 체크밸브(22)를 통과한 후, 제1 유로(185)를 통해 선회모터(110)의 A포트에 공급된다. 이때, 상부 선회체(20)의 회전이 완전히 멈춘 후, 인가되는 파일럿 신호압에 따라 스풀밸브(144)가 좌측방향(도면 기준)으로 절환되면, 제1 실린더(141)는 유압탱크(13)와 연결된다. 이에 따라, 제1 실린더(141)에 공급되어 있던 작동유는 유압탱크(13)로 드레인된다. 이와 같이, 제1 실린더(141)로부터 작동유가 모두 빠져나가면, 제1 실린더(141)에는 압력이 형성되지 않으므로, MCV 리턴 유로(15)를 이동하는 작동유가 압력 차에 따라 제2 실린더(142)에 자동으로 채워지게 된다.Next, section 2 of FIG. 2 shows the pressure change when the upper swing body 20 rotating in the forward direction is suddenly decelerated, that is, when the flow control valve 120 is switched to the neutral position. The upper pivot 20 does not immediately stop rotating due to the large weight and rotational inertia. That is, when the flow control valve 120 is switched to the neutral position, the hydraulic oil discharged from the B port of the swing motor 110 due to the continuous operation of the swing motor 110 by the continuously rotating upper swing body 20. Overload is generated in the second flow path 186 to which is moved. The hydraulic fluid corresponding to the overload formed in the second flow path 186 passes through the fifth check valve 25 installed in the fourth flow path 188. The high pressure hydraulic oil flowing into the fourth flow passage 188 between the fourth check valve 24 and the fifth check valve 25 from the second flow passage 186 through the fifth check valve 25 is passed through the regeneration passage. It is stored in the accumulator 130 installed at 181. At this time, due to the continuous operation of the swing motor 110, the hydraulic oil shortage required for the A port of the swing motor 110 is supplied through the boost device 140. That is, when the flow control valve 120 is switched to the neutral position, when the spool valve 144 is switched in the right direction (reference to the drawing) by the pilot signal pressure applied, the accumulator 130 may supply the first supply passage 182. It is connected to the first cylinder 141 through). Accordingly, the working oil discharged from the accumulator 130 moves through the first supply passage 182 and is supplied to the first cylinder 141 via the spool valve 144. At this time, since the first cylinder 141 has a smaller area than the second cylinder 142 connected to the piston 143 through the piston 143, a high pressure is formed in the first cylinder 141, the second cylinder 142 In the low pressure corresponding to the pressure formed in the first cylinder 141 is formed. Accordingly, the piston 143 is moved to the second cylinder 142 side by the high-pressure hydraulic oil pressure supplied to the first cylinder 141, and due to the movement of the piston 143, the second cylinder 142 The hydraulic oil filled in is pressurized and discharged from the second cylinder 142. As such, the hydraulic oil discharged from the second cylinder 142 flows into the third flow path 187 between the second check valve 22 and the third check valve 23 along the second supply passage 183. . The hydraulic oil introduced into the third flow path 187 passes through the second check valve 22, and is then supplied to the A port of the swing motor 110 through the first flow path 185. At this time, after the rotation of the upper pivot 20 is completely stopped, when the spool valve 144 is switched in the left direction (based on the drawing) according to the applied pilot signal pressure, the first cylinder 141 is the hydraulic tank 13 Connected with Accordingly, the hydraulic oil supplied to the first cylinder 141 is drained to the hydraulic tank 13. As such, when all the hydraulic oil is released from the first cylinder 141, since no pressure is formed in the first cylinder 141, the hydraulic oil for moving the MCV return flow path 15 is changed to the second cylinder 142 according to the pressure difference. Will be filled in automatically.
다음으로, 도 2의 구간3은 상부 선회체(20)가 역방향으로 선회되는 경우의 압력 변화를 나타낸 것으로, 인가되는 파일럿 신호압에 의해 유량제어밸브(120)가 우측방향(도면 기준)으로 절환되면, 유압펌프(11)는 제2 유로(186)를 통해 선회모터(110)의 B포트에 연결되고, 선회모터(110)의 A포트는 제1 유로(185)를 통해 유압탱크(13)와 연결된다. 이에 따라, 유압펌프(11)로부터 토출되는 작동유는 유량제어밸브(120)를 경유하여 제2 유로(186)를 따라 선회모터(110)의 B포트에 공급되고, 이로 인해, 선회모터(110)는 역방향으로 회전하게 된다. 이때, 선회모터(110)의 A포트로부터 배출되는 작동유는 제1 유로(185)를 통해 유압탱크(13)로 귀환된다.Next, section 3 of FIG. 2 shows the pressure change when the upper swing body 20 is rotated in the reverse direction, and the flow control valve 120 is switched to the right direction (based on the drawing) by the applied pilot signal pressure. When the hydraulic pump 11 is connected to the B port of the swing motor 110 through the second flow path 186, the A port of the swing motor 110 is connected to the hydraulic tank 13 through the first flow path 185. Connected with Accordingly, the hydraulic oil discharged from the hydraulic pump 11 is supplied to the B port of the swing motor 110 along the second flow path 186 via the flow control valve 120, thereby, the swing motor 110. Will rotate in the reverse direction. At this time, the hydraulic oil discharged from the A port of the swing motor 110 is returned to the hydraulic tank 13 through the first flow path (185).
다음으로, 도 2의 구간4는 역방향으로 선회하고 있는 상부 선회체(20)를 급격하게 감속시키는 경우, 즉, 유량제어밸브(120)를 중립위치로 전환시킨 경우 압력 변화를 나타낸 것으로, 이 경우, 상부 선회체(20)는 큰 중량 및 회전 관성력으로 인해 곧바로 회전을 멈추지 못한다. 즉, 유량제어밸브(120)를 중립위치로 전환시킨 경우, 계속적으로 회전하는 상부 선회체(20)에 의한 선회모터(110)의 계속 동작으로 인해 선회모터(110)의 A포트로부터 배출되는 작동유가 이동하는 제1 유로(185)에는 과부하가 발생된다. 제1 유로(185)에 형성되는 과부하에 해당되는 작동유는 제4 유로(188)에 설치되어 있는 제4 체크밸브(24)를 통과한다. 그리고 제1 유로(185)로부터 제4 체크밸브(24)를 통해, 제4 체크밸브(24) 및 제5 체크밸브(25) 사이의 제4 유로(188)에 유입된 고압의 작동유는 재생통로(181)에 설치되어 있는 어큐뮬레이터(130)에 저장된다. 이때, 선회모터(110)의 계속적인 동작으로 인해 선회모터(110)의 B포트에 요구되는 작동유 부족분은 부스트 장치(140)를 통해 공급된다. 즉, 유량제어밸브(120)가 중립위치로 전환된 경우, 인가되는 파일럿 신호압에 의해 스풀밸브(144)가 우측방향(도면 기준)으로 절환되면, 어큐뮬레이터(130)는 제1 공급통로(182)를 통해 제1 실린더(141)에 연결된다. 이에 따라, 어큐뮬레이터(130)로부터 배출되는 작동유는 제1 공급통로(182)를 통해 이동하다가 스풀밸브(144)를 경유하여 제1 실린더(141)에 공급된다. 이때, 제1 실린더(141)는 이와 피스톤(143)을 매개로 연결되어 있는 제2 실린더(142)보다 면적이 작으므로, 제1 실린더(141)에는 고압이 형성되고, 제2 실린더(142)에는 제1 실린더(141)에 형성된 압력에 상응하는 저압이 형성된다. 이에 따라, 피스톤(143)은 제1 실린더(141)에 공급되는 작동유의 압력에 밀려 제2 실린더(142) 측으로 이동하게 되고, 이러한 피스톤(143)의 이동으로 인해, 제2 실린더(142)에 충전되어 있는 작동유는 가압되어, 제2 실린더(142)로부터 배출된다. 이와 같이, 제2 실린더(142)로부터 배출되는 작동유는 제2 공급통로(183)를 따라, 제2 체크밸브(22) 및 제3 체크밸브(23) 사이의 제3 유로(187)에 유입된다. 제3 유로(187)에 유입된 작동유는 제3 체크밸브(23)를 통과한 후, 제2 유로(186)를 통해 선회모터(110)의 B포트에 공급된다. 이때, 상부 선회체(20)의 회전이 완전히 멈춘 후, 인가되는 파일럿 신호압에 따라 스풀밸브(144)가 좌측방향(도면 기준)으로 절환되면, 제1 실린더(141)는 유압탱크(13)와 연결된다. 이에 따라, 제1 실린더(141)에 공급되어 있던 작동유는 유압탱크(13)로 드레인된다. 이와 같이, 제1 실린더(141)로부터 작동유가 모두 빠져나가면, 제1 실린더(141)에는 압력이 형성되지 않으므로, MCV 리턴 유로(15)를 이동하는 작동유가 압력 차에 따라 제2 실린더(142)에 자동으로 채워지게 된다.Next, section 4 of FIG. 2 shows the pressure change when the upper swing body 20 turning in the reverse direction is sharply decelerated, that is, when the flow control valve 120 is switched to the neutral position. The upper pivot 20 does not immediately stop rotating due to the large weight and rotational inertia. That is, when the flow control valve 120 is switched to the neutral position, the hydraulic oil discharged from the A port of the swing motor 110 due to the continuous operation of the swing motor 110 by the continuously rotating upper swing body 20. Overload is generated in the first flow path 185 to which is moved. The hydraulic fluid corresponding to the overload formed in the first flow path 185 passes through the fourth check valve 24 installed in the fourth flow path 188. The high pressure hydraulic oil introduced into the fourth flow path 188 between the fourth check valve 24 and the fifth check valve 25 from the first flow path 185 through the fourth check valve 24 is regenerated. It is stored in the accumulator 130 installed at 181. At this time, the hydraulic oil shortage required for the B port of the swing motor 110 is supplied through the boost device 140 due to the continuous operation of the swing motor 110. That is, when the flow control valve 120 is switched to the neutral position, when the spool valve 144 is switched in the right direction (reference to the drawing) by the pilot signal pressure applied, the accumulator 130 may supply the first supply passage 182. It is connected to the first cylinder 141 through). Accordingly, the working oil discharged from the accumulator 130 moves through the first supply passage 182 and is supplied to the first cylinder 141 via the spool valve 144. At this time, since the first cylinder 141 has a smaller area than the second cylinder 142 connected to the piston 143 through the piston 143, a high pressure is formed in the first cylinder 141, the second cylinder 142 In the low pressure corresponding to the pressure formed in the first cylinder 141 is formed. Accordingly, the piston 143 is moved to the second cylinder 142 side by the pressure of the hydraulic oil supplied to the first cylinder 141, due to the movement of the piston 143, to the second cylinder 142 The filled hydraulic oil is pressurized and discharged from the second cylinder 142. As such, the hydraulic oil discharged from the second cylinder 142 flows into the third flow path 187 between the second check valve 22 and the third check valve 23 along the second supply passage 183. . The working oil introduced into the third flow path 187 passes through the third check valve 23 and is supplied to the B port of the swing motor 110 through the second flow path 186. At this time, after the rotation of the upper pivot 20 is completely stopped, when the spool valve 144 is switched in the left direction (based on the drawing) according to the applied pilot signal pressure, the first cylinder 141 is the hydraulic tank 13 Connected with Accordingly, the hydraulic oil supplied to the first cylinder 141 is drained to the hydraulic tank 13. As such, when all the hydraulic oil is released from the first cylinder 141, since no pressure is formed in the first cylinder 141, the hydraulic oil for moving the MCV return flow path 15 is changed to the second cylinder 142 according to the pressure difference. Will be filled in automatically.
한편, 도 3에 도시한 바와 같이, 본 발명의 다른 실시 예에 따른 건설기계용 유압 시스템(200)은 유압 액츄에이터, 유량제어밸브(120), 어큐뮬레이터(130) 및 부스트 장치(240)를 포함하여 형성된다.Meanwhile, as shown in FIG. 3, the hydraulic system 200 for a construction machine according to another embodiment of the present invention includes a hydraulic actuator, a flow control valve 120, an accumulator 130, and a boost device 240. Is formed.
본 발명의 다른 실시 예는 본 발명의 일 실시 예와 비교하여, 부스트 장치의 구조에만 차이가 있을 뿐이므로, 동일한 구성요소들에 대해서는 동일한 도면부호를 부여하고, 이들에 대한 상세한 설명은 생략하기로 한다.Since other embodiments of the present invention differ only in the structure of the boost device compared to the embodiment of the present invention, the same reference numerals are assigned to the same elements, and detailed description thereof will be omitted. do.
본 발명의 다른 실시 예에 따른 부스트 장치(240)는 제1 실린더(241), 제2 실린더(242) 및 피스톤(243)을 포함한다. 제1 실린더(241)는 어큐뮬레이터(130)와 연결된다. 또한, 제2 실린더(242)는 제1 실린더(241)와 연결된다. 이때, 제2 실린더(242)는 제1 실린더(241)보다 상대적으로 큰 면적으로 형성된다. 피스톤(243)은 제1 실린더(241)와 제2 실린더(242) 사이에서 이들을 연결하는 형태로 형성된다. 이러한 피스톤(243)은 제1 실린더(241)에 공급되거나 제2 실린더(242)에 충전되는 작동유에 의해 제1 실린더(241)와 제2 실린더(242) 사이를 왕복 운동한다.The boost device 240 according to another embodiment of the present invention includes a first cylinder 241, a second cylinder 242, and a piston 243. The first cylinder 241 is connected to the accumulator 130. In addition, the second cylinder 242 is connected to the first cylinder 241. At this time, the second cylinder 242 is formed with a relatively larger area than the first cylinder 241. The piston 243 is formed in the form of connecting them between the first cylinder 241 and the second cylinder 242. The piston 243 reciprocates between the first cylinder 241 and the second cylinder 242 by the hydraulic oil supplied to the first cylinder 241 or filled in the second cylinder 242.
본 발명의 일 실시 예에서, 제1 실린더(도 1의 141)와 제2 실린더(도 1의 142)는 하나의 바디를 이루는 형태로 형성된 반면, 본 발명의 다른 실시 예에서, 제1 실린더(241)와 제2 실린더(242)는 서로 독립적인 형태로 형성된다.In one embodiment of the present invention, the first cylinder (141 of FIG. 1) and the second cylinder (142 of FIG. 1) is formed in the form of a body, while in another embodiment of the present invention, the first cylinder ( The 241 and the second cylinder 242 are formed to be independent of each other.
이와 같이, 본 발명의 실시 예에서, 제1 실린더(141, 241)가 제2 실린더(142, 242)보다 상대적으로 작은 면적으로 형성되는 경우, 그 작용 및 효과는 동일하므로, 유압 시스템(100, 200)에 최적화될 수 있도록, 제1 실린더(141, 241)와 제2 실린더(142, 242)는 다양한 형태나 구조로 이루어질 수 있다.As such, in the embodiment of the present invention, when the first cylinders 141 and 241 are formed with a relatively smaller area than the second cylinders 142 and 242, the actions and effects are the same, and thus the hydraulic system 100, In order to be optimized for the 200, the first cylinders 141 and 241 and the second cylinders 142 and 242 may have various shapes or structures.
이상과 같이 본 발명은 비록 한정된 실시 예와 도면에 의해 설명되었으나, 본 발명은 상기의 실시 예에 한정되는 것은 아니며, 본 발명이 속하는 분야에서 통상의 지식을 가진 자라면 이러한 기재로부터 다양한 수정 및 변형이 가능하다.As described above, although the present invention has been described with reference to the limited embodiments and the drawings, the present invention is not limited to the above embodiments, and those skilled in the art to which the present invention pertains various modifications and variations from such descriptions. This is possible.
그러므로 본 발명의 범위는 설명된 실시 예에 국한되어 정해져서는 아니 되며, 후술하는 특허청구범위뿐만 아니라 특허청구범위와 균등한 것들에 의해 정해져야 한다.Therefore, the scope of the present invention should not be limited to the described embodiments, but should be determined not only by the claims below but also by the equivalents of the claims.

Claims (14)

  1. 유압펌프와 연결되고, 상기 유압펌프로부터 토출되어 공급되고 유압탱크로 귀환하는 작동유에 의해 구동되는 유압 액츄에이터;A hydraulic actuator connected to the hydraulic pump and driven by hydraulic oil discharged from the hydraulic pump and supplied to the hydraulic tank;
    상기 유압펌프와 상기 유압 액츄에이터 및 상기 유압 액츄에이터와 상기 유압탱크 사이를 이동하는 작동유의 이동 경로 상에 설치되어, 작동유의 이동을 제어하는 유량제어밸브;A flow control valve installed on the hydraulic pump and the hydraulic actuator and a moving path of the hydraulic oil moving between the hydraulic actuator and the hydraulic tank to control the movement of the hydraulic oil;
    상기 유압탱크로 향하는 작동유의 이동 경로로부터 분기되어 있는 재생통로에 설치되고, 상기 유량제어밸브가 중립위치로 전환되는 경우, 상기 재생통로로 유입되는 작동유를 저장하는 어큐뮬레이터;An accumulator installed in the regeneration passage branched from the movement path of the hydraulic oil directed to the hydraulic tank and storing the hydraulic oil flowing into the regeneration passage when the flow control valve is switched to the neutral position;
    상기 어큐뮬레이터와 연결되고, 상기 유량제어밸브가 중립위치로 전환되어, 상기 유압펌프로부터 토출되는 작동유가 상기 유압 액츄에이터로 공급되지 못하는 경우, 상기 어큐뮬레이터에 저장되어 있는 작동유를 이용하여, 상기 유압 액츄에이터의 계속 동작으로 인해 요구되는 작동유 부족분을 상기 유압 액츄에이터에 공급하는 부스트 장치;When the hydraulic fluid connected to the accumulator and the flow control valve is switched to the neutral position and the hydraulic oil discharged from the hydraulic pump cannot be supplied to the hydraulic actuator, using the hydraulic oil stored in the accumulator, the hydraulic actuator is continued. A boost device for supplying a hydraulic oil shortage required by the operation to the hydraulic actuator;
    를 포함하는 건설기계용 유압시스템.Hydraulic system for construction machinery comprising a.
  2. 제1항에 있어서,The method of claim 1,
    상기 부스트 장치는,The boost device,
    상기 어큐뮬레이터와 연결되는 제1 실린더,A first cylinder connected to the accumulator,
    상기 제1 실린더와 연결되고 상기 제1 실린더보다 상대적으로 큰 면적으로 형성되며 상기 제1 실린더에 상기 어큐뮬레이터로부터 작동유가 공급되는 경우 내부에 충전되어 있는 작동유를 상기 유압 액츄에이터 측으로 배출하는 제2 실린더, 및A second cylinder connected to the first cylinder and formed with a larger area than the first cylinder, and discharging the hydraulic oil filled therein to the hydraulic actuator when the hydraulic oil is supplied from the accumulator to the first cylinder;
    상기 제1 실린더와 상기 제2 실린더를 연결하는 형태로 상기 제1 실린더와 상기 제2 실린더 사이에 설치되어, 상기 제1 실린더에 공급되거나 상기 제2 실린더에 충전되는 작동유에 의해 상기 제1 실린더와 상기 제2 실린더 사이를 왕복 운동하는 피스톤을 포함하는 건설기계용 유압시스템.The first cylinder is installed between the first cylinder and the second cylinder in a form of connecting the first cylinder and the second cylinder, and is supplied to the first cylinder or filled with the second cylinder. Hydraulic system for a construction machine including a piston for reciprocating between the second cylinder.
  3. 제2항에 있어서,The method of claim 2,
    상기 제1 실린더와 상기 제2 실린더는 하나의 바디를 이루는 형태로 형성되거나 서로 독립적인 형태로 형성되는 건설기계용 유압시스템.The first cylinder and the second cylinder is a hydraulic system for construction machinery is formed in the form of a body or in a form independent of each other.
  4. 제2항에 있어서,The method of claim 2,
    상기 부스트 장치는 상기 어큐뮬레이터와 상기 제1 실린더 사이를 연결하는 제1 공급통로에 설치되어 상기 어큐뮬레이터로부터 상기 제1 실린더로의 작동유 이동 및 상기 제1 실린더로부터 상기 유압탱크로의 작동유 이동을 제어하는 스풀밸브를 더 포함하는 건설기계용 유압시스템.The boost device is installed in a first supply passage connecting between the accumulator and the first cylinder, the spool controlling hydraulic oil movement from the accumulator to the first cylinder and hydraulic oil movement from the first cylinder to the hydraulic tank. Hydraulic system for construction machinery further comprising a valve.
  5. 제4항에 있어서,The method of claim 4, wherein
    상기 제2 실린더는 제2 공급통로를 통해 상기 유압 액츄에이터와 연결되는 건설기계용 유압시스템.And the second cylinder is connected to the hydraulic actuator through a second supply passage.
  6. 제5항에 있어서,The method of claim 5,
    상기 제2 실린더는 제2 공급통로에 접속되는 제3 공급통로를 통해 MCV 리턴 유로와 연결되는 건설기계용 유압시스템.And the second cylinder is connected to the MCV return passage through a third supply passage connected to the second supply passage.
  7. 제6항에 있어서,The method of claim 6,
    상기 제3 공급통로는 상기 MCV 리턴 유로에서 상기 제2 실린더 측으로 일 방향으로의 작동유 이동을 허용하는 제1 체크밸브를 포함하는 건설기계용 유압시스템.And the third supply passage includes a first check valve to allow hydraulic fluid movement in one direction from the MCV return flow passage to the second cylinder side.
  8. 제7항에 있어서,The method of claim 7, wherein
    상기 제1 실린더로부터 상기 유압탱크로 작동유 이동이 가능하도록 상기 스풀밸브가 절환되는 경우, 상기 MCV 리턴 유로를 이동하는 작동유가 압력 차에 따라 상기 제2 실린더에 자동 충전되는 건설기계용 유압시스템.When the spool valve is switched so that the hydraulic fluid can be moved from the first cylinder to the hydraulic tank, the hydraulic oil for moving the MCV return flow path is automatically filled in the second cylinder in accordance with the pressure difference.
  9. 제1항에 있어서,The method of claim 1,
    상기 유압 액츄에이터는 선회모터 또는 어태치먼트용 유압 실린더인 건설기계용 유압시스템.The hydraulic actuator is a hydraulic system for construction machinery is a hydraulic cylinder for swing motor or attachment.
  10. 제1항에 있어서,The method of claim 1,
    상기 유압펌프와 상기 유압 액츄에이터를 연결시키는 제1 유로 및 제2 유로를 더 포함하는 건설기계용 유압시스템.And a first flow passage and a second flow passage connecting the hydraulic pump and the hydraulic actuator.
  11. 제10항에 있어서,The method of claim 10,
    상기 제1 유로 및 상기 제2 유로에 양단이 분기 접속되고, 상기 부스트 장치로부터 상기 제1 유로 및 상기 제2 유로 측으로 일 방향으로의 작동유 이동을 각각 허용하는 제2 및 제3 체크밸브가 각각 설치되는 제3 유로, 및Both ends are branch-connected to the first flow path and the second flow path, and second and third check valves are respectively provided to allow movement of hydraulic fluid in one direction from the boost device to the first flow path and the second flow path. The third euro, and
    상기 제3 유로와 병렬형을 이루는 형태로 상기 제1 유로 및 상기 제2 유로의 상류측에 양단이 분기 접속되고, 상기 제1 유로 또는 상기 제2 유로에서 상기 유압탱크 측으로 일 방향으로의 작동유 이동을 각각 허용하는 제4 및 제5 체크밸브가 각각 설치되는 제4 유로를 더 포함하는 건설기계용 유압시스템.Both ends are branched to an upstream side of the first flow path and the second flow path in a form parallel to the third flow path, and the hydraulic fluid moves in one direction from the first flow path or the second flow path to the hydraulic tank side. Hydraulic system for a construction machine further comprises a fourth flow path is respectively installed to allow the fourth and fifth check valve.
  12. 제1항에 있어서,The method of claim 1,
    상기 어큐뮬레이터와 엔진에 연결되어 있는 유압모터 사이의 상기 재생통로에 설치되어 상기 재생통로의 개폐를 제어하는 단속밸브를 더 포함하는 건설기계용 유압시스템.And an intermittent valve installed in the regeneration passage between the accumulator and the hydraulic motor connected to the engine to control the opening and closing of the regeneration passage.
  13. 제1항에 있어서,The method of claim 1,
    상기 어큐뮬레이터의 상류측 상기 재생통로에 설치되고, 상기 재생통로의 압력을 검출하는 압력센서를 더 포함하는 건설기계용 유압시스템.And a pressure sensor installed in the regeneration passage upstream of the accumulator, the pressure sensor detecting the pressure of the regeneration passage.
  14. 제13항에 있어서,The method of claim 13,
    상기 압력센서의 상류측 상기 재생통로에 설치되고, 상기 압력센서에 의해 검출되는 압력 값을 토대로 설정된 제어신호 값에 의해 입구측 포트와 출구측 포트 간의 압력 차를 가변 조정하는 가변 릴리프밸브를 더 포함하는 건설기계용 유압시스템.And a variable relief valve installed in the regeneration passage upstream of the pressure sensor and variably adjusting a pressure difference between the inlet port and the outlet port by a control signal value set based on the pressure value detected by the pressure sensor. Hydraulic system for construction machinery.
PCT/KR2015/013360 2015-12-08 2015-12-08 Hydraulic system for construction machine WO2017099265A1 (en)

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