KR100473238B1 - Hydraulic system for construction machinery and its control method - Google Patents

Hydraulic system for construction machinery and its control method Download PDF

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Publication number
KR100473238B1
KR100473238B1 KR1019970074591A KR19970074591A KR100473238B1 KR 100473238 B1 KR100473238 B1 KR 100473238B1 KR 1019970074591 A KR1019970074591 A KR 1019970074591A KR 19970074591 A KR19970074591 A KR 19970074591A KR 100473238 B1 KR100473238 B1 KR 100473238B1
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South Korea
Prior art keywords
bucket
hydraulic pump
cylinder
boom
engine
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KR1019970074591A
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Korean (ko)
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KR19990054725A (en
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기 정 김
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볼보 컨스트럭션 이키프먼트 홀딩 스웨덴 에이비
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Priority to KR1019970074591A priority Critical patent/KR100473238B1/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
    • E02F9/2221—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
    • E02F3/00—Dredgers; Soil-shifting machines
    • E02F3/04—Dredgers; Soil-shifting machines mechanically-driven
    • E02F3/28—Dredgers; Soil-shifting machines mechanically-driven with digging tools mounted on a dipper- or bucket-arm, i.e. there is either one arm or a pair of arms, e.g. dippers, buckets
    • E02F3/36—Component parts
    • E02F3/42—Drives for dippers, buckets, dipper-arms or bucket-arms
    • E02F3/422—Drive systems for bucket-arms, front-end loaders, dumpers or the like

Abstract

본 발명은 휠로다와 같은 건설기계용 유압시스템 및 그 제어방법에 관한 것으로, 엔진구동력을 이용하여 작업장치로서의 버켓을 작동시키도록 메인 유압펌프(6)와 보조유압펌프(7), 상기 유압펌프들로 부터 공급되는 압유를 상기 버켓구동용 버켓실린더(4)와 붐실린더(5)로 공급하도록 제어하는 컨트롤 밸브장치(8)를 구비하며, 상기 버켓승강을 위하여 붐을 신속하게 상승시키도록함에 요구되는 구동력을 얻기 위하여 미리 설정된 조건을 충족하는 경우에 따라 보조 유압펌프의 작동을 제어하는 신호를 출력하는 스위치수단(12)과, 그에 응답하여 상기 보조유압펌프(7)로 부터 토출되는 압유의 유로를 메인 유압펌프(6)로부터 컨트롤밸브장치(8)로의 유로에 선택적으로 연통시키도록 하는 방향제어밸브(14)와, 엔진 회전속도와 버켓실린더와 붐실린더의 동작상태에 따라 보조유압펌프를 선택적으로 구동시키도록 상기 스위치수단(12)의 온오프를 제어하는 컨트롤러(16)를 포함하여 구성됨으로써, 붐실린더로의 유입유량을 집중되게 제어하여 붐이 신속하게 상승하게 되므로 붐을 이용한 작업을 효율적으로 수행할 수 있고, 특히 엔진에 무리를 주지않고 과도한 연료소모도 방지하게 되는 장점이 있다.The present invention relates to a hydraulic system for a construction machine such as a wheel loader, and a control method thereof. The main hydraulic pump (6), the auxiliary hydraulic pump (7), and the hydraulic pump are operated to operate a bucket as a work device using an engine driving force. And a control valve device (8) for controlling the hydraulic oil supplied from the bucket to the bucket driving bucket cylinder (4) and the boom cylinder (5), so as to quickly raise the boom for lifting the bucket. Switch means 12 for outputting a signal for controlling the operation of the auxiliary hydraulic pump in accordance with the pre-set conditions to obtain the required driving force, and in response to the pressure of the hydraulic oil discharged from the auxiliary hydraulic pump (7) Directional control valve 14 for selectively communicating the flow path to the flow path from the main hydraulic pump 6 to the control valve device 8, the engine rotation speed, the bucket cylinder and the boom cylinder It is configured to include a controller 16 for controlling the on-off of the switch means 12 to selectively drive the auxiliary hydraulic pump according to the state, thereby intensively controlling the inflow flow into the boom cylinder to raise the boom quickly Since it is possible to efficiently perform the work using the boom, in particular, there is an advantage that prevents excessive fuel consumption without overloading the engine.

Description

건설기계용 유압시스템 및 그 제어방법Hydraulic system for construction machinery and its control method

본 발명은 휠로다를 비롯한 건설기계의 작업장치용 유압시스템의 구조개선에 관한 것으로, 특히 작업장치의 구동을 위하여 엔진구동력을 이용하는 유압펌프의 구동이 효율적으로 이루어지도록 하여 작업장치의 붐상승속도를 증가시키도록 하는 작업장치용 유압시스템 그 제어방법에 관한 것이다.The present invention relates to a structural improvement of a hydraulic system for a work machine of a construction machine, including a wheel loader, and in particular, to increase the boom rising speed of the work machine by efficiently driving a hydraulic pump using an engine driving force for driving the work machine. It relates to a control method of a hydraulic system for a work device to make.

일반적으로, 휠로다와 같은 건설기계에는 엔진구동력을 이용하는 유압펌프에 의해 발생된 유압을 이용하여 버켓과 같은 작업장치를 작동하게 된다. 즉, 도 1에 도시된 휠로다(1)는 버켓(2)을 작동하기 위하여 프런트 프레임(3)에 회동가능하게 장착되어 버켓을 회동가능하게 하는 두개의 붐실린더(5)와, 버켓(2)을 상하방향으로 승하강시키는 하나의 버켓실린더(4)를 구비하고 있으며 상기 붐실린더(5)와 버켓실린더(4)의 작동은 도 2에 도시된 바와같은 작업장치구동용 유압시스템에 의해 수행된다.In general, a construction machine such as a wheel loader uses a hydraulic pressure generated by a hydraulic pump using an engine driving force to operate a work device such as a bucket. That is, the wheel loader 1 shown in FIG. 1 is rotatably mounted on the front frame 3 to operate the bucket 2, and the two boom cylinders 5 for turning the bucket and the bucket 2 ) Is provided with a bucket cylinder (4) for raising and lowering in the vertical direction, the operation of the boom cylinder (5) and the bucket cylinder (4) is carried out by a hydraulic system for work device drive as shown in FIG. do.

종래의 유압시스템은 휠로다(1)의 엔진구동력에 의해 구동되는 2개의 유압펌프(6,7)와 그로부터 공급되는 압유를 메인 컨트롤 밸브장치(8)와 서보 컨트롤 밸브(9)의 제어하에 유로를 선택적으로 개폐시켜 상기 붐실린더(5)와 버켓실린더(4)를 작동시키도록 되어 있다.The conventional hydraulic system uses two hydraulic pumps 6 and 7 driven by the engine driving force of the wheel loader 1 and the hydraulic oil supplied therefrom under the control of the main control valve device 8 and the servo control valve 9. By selectively opening and closing the boom cylinder (5) and the bucket cylinder (4) to operate.

그러나, 상기와 같은 유압시스템에 의해 구동되는 작업장치, 특히 붐의 동작속도는 붐실린더의 직경, 펌프의 유량 및 엔진 회전속도에 영향을 받게 되며, 엔진 회전속도와 붐실린더가 같다면 붐의 상승속도는 펌프의 유량에 따라 증가된다. 그러나, 종래의 유압시스템에서는 2개의 유압펌프가 항상 작동하게 되어있으나 유압펌프의 구동은 엔진 출력에 대한 소요 토오크의 제한을 받아 일정 크기 이상의 펌프를 사용할 수 없어서 붐의 상승속도 증가를 위해 토출유량이 큰 유압펌프의 사용에 제약이 따르는 문제가 있었다.However, the operating speed of the working device, in particular the boom, driven by the hydraulic system as described above is affected by the diameter of the boom cylinder, the flow rate of the pump and the engine rotation speed, and if the engine rotation speed is equal to the boom cylinder, The speed increases with the flow rate of the pump. However, in the conventional hydraulic system, the two hydraulic pumps are always operated, but the driving of the hydraulic pump is limited by the required torque for the engine output, so that a pump having a certain size or more cannot be used and the discharge flow rate is increased to increase the boom's ascent speed. There is a problem in that the use of a large hydraulic pump is limited.

본 발명은 상술한 종래의 휠로다와 같은 건설기계의 작업장치 구동용 유압시스템에 따른 문제를 해소하기 위한 것으로, 건설기계의 작업장치를 신속하게 작동시킬 수 있도록 보조유압펌프로 부터의 토출압유를 일정한 작업조건에서 전자제어하에 선택적으로 작업장치용 유압실린더로 향하게 하는 유압시스템과 그 제어방법의 제공을 목적으로 한다.The present invention is to solve the problems caused by the hydraulic system for driving a work device of a construction machine, such as the conventional wheel loader described above, the discharge pressure oil from the auxiliary hydraulic pump to quickly operate the work machine of the construction machine An object of the present invention is to provide a hydraulic system and a control method thereof, which are directed to a hydraulic cylinder for a work device under electronic control under certain working conditions.

상기한 목적을 달성하기 위하여, 본 발명에 따른 건설기계용 유압시스템은 엔진구동에 의해 작업장치들 구동에 필요한 작동유를 토출하는 메인 유압펌프와 보조유압펌프, 상기 유압펌프들로 부터 공급되는 압유를 상기 작업장치들로 선택적으로 공급하도록 제어하는 컨트롤 밸브장치, 상기 보조유압펌프로 부터 토출되는 압유의 유로를 메인 유압펌프로부터 컨트롤 밸브장치로의 유로에 선택적으로 연통시키도록 제공된 방향제어밸브, 상기 작업장치의 실린더들에서 필요한 구동력을 증가시키기 위하여 보조 유압펌프의 토출압유 흐름을 제어하도록 방향제어밸브를 전환시키는 신호를 출력하는 스위치수단, 엔진 회전속도와 작업장치의 작업조건에 따라 스위치수단의 온오프를 제어하는 컨트롤러를 포함하여 구성된다.In order to achieve the above object, the hydraulic system for construction machinery according to the present invention is the main hydraulic pump and auxiliary hydraulic pump for discharging the hydraulic oil required for driving the working apparatus by the engine drive, the hydraulic oil supplied from the hydraulic pump A control valve device for selectively supplying to the work devices, a direction control valve provided to selectively communicate a flow path of the pressurized oil discharged from the auxiliary hydraulic pump from a main hydraulic pump to a flow path from the main hydraulic pump to the control valve device; Switch means for outputting a signal for switching the directional control valve to control the discharge pressure oil flow of the auxiliary hydraulic pump to increase the required driving force in the cylinders of the device, on and off of the switch means depending on the engine rotational speed and the working conditions of the working device It is configured to include a controller to control the.

상기 유압시스템은 엔진 회전속도가 소정의 기준치 이상인지를 판단하고, 엔진 회전속도가 소정기준 이상일 경우 버켓실린더 작동유무를 판별하고, 이어서 버켓실린더가 작동중일 경우 붐실린더가 소정의 압력 이상인지를 판별하여 붐실린더의 압력이 기준치 이상인 경우 보조유압펌프의 토출압유를 작업장치의 실린더로 향하도록 방향제어밸브 제어용 스위치수단을 온시키는 단계들을 포함하는 유압제어방법이 제공된다.The hydraulic system determines whether the engine rotation speed is greater than or equal to a predetermined reference value. If the engine rotation speed is greater than or equal to a predetermined reference value, the hydraulic system determines whether the bucket cylinder is operating. Then, if the bucket cylinder is in operation, the boom cylinder is greater than or equal to the predetermined pressure. When the pressure of the boom cylinder is more than the reference value is provided a hydraulic control method comprising the step of turning on the switch means for controlling the direction control valve to direct the discharge pressure oil of the auxiliary hydraulic pump to the cylinder of the working device.

이하, 본 발명의 실시예를 도시한 첨부된 도면을 참고하여 본 발명을 상세히 설명하기로 한다.Hereinafter, with reference to the accompanying drawings showing an embodiment of the present invention will be described in detail the present invention.

도 3은 본 발명에 따른 건설기계의 한 예로 휠로다용 유압시스템의 유압 회로도를 보여주고 있다. 도면에서 휠로다(1)는 버켓(2)을 작동하기 위하여 프런트 프레임(3)에 회동가능하게 장착되어 버켓을 회동가능하게 하는 두개의 붐실린더(5)와, 버켓(2)을 상하방향으로 승하강시키는 하나의 버켓실린더(4)에 선택적으로 유압을 공급하도록 메인 컨트롤밸브장치(8)는 붐실린더 제어용 방향제어밸브(10)와 버켓실린더 제어용 방향제어밸브(11)를 구비하고 상기 방향제어밸브(10,11)의 제어를 위하여 서보 컨트롤밸브(9)가 제공된다.3 shows a hydraulic circuit diagram of a hydraulic system for a wheel loader as an example of a construction machine according to the present invention. In the figure, the wheel loader 1 is rotatably mounted to the front frame 3 to operate the bucket 2, and the two boom cylinders 5 for turning the bucket and the bucket 2 in the vertical direction. The main control valve device 8 includes a boom cylinder control direction control valve 10 and a bucket cylinder control direction control valve 11 so as to selectively supply hydraulic pressure to one bucket cylinder 4 which moves up and down. A servo control valve 9 is provided for the control of the valves 10, 11.

도면에서는 메인 유압펌프(6)로 부터의 압유가 상기 붐실린더들로 향하지 않고 붐실린더들로 부터도 압유가 흐르지 않게 되어 작업장치가 정지된 상태를 도시하고 있으며, 방향제어밸브(11)가 위치(a)에 있게 되면 붐실린더의 피스톤이 전진하도록 압유가 공급되어 붐이 승강되고, 위치(b)에서는 그 유압흐름이 반대로 되어 붐이 하강하도록 되고 위치(c)에 있으면 작업장치 자체의 하중에 의해 붐이 하강된다. 또한, 방향제어밸브(10)가 위치(d)에 있게 되면 버켓실린더(4)로 압유가 공급되어 피스톤이 전진하여 버켓이 하향되는 반면, 위치(e)에 있을 때는 압유흐름이 반대로 되어 버켓실린더의 피스톤이 후퇴하여 버켓이 상향된다. 이러한 작동을 위한 밸브(10,11)의 제어는 보조 컨트롤 밸브(9)에 의해 수행된다.In the drawing, the hydraulic oil from the main hydraulic pump 6 is not directed to the boom cylinders, and the hydraulic oil does not flow from the boom cylinders, and the working device is stopped. The direction control valve 11 is positioned. When it is in position (a), the hydraulic oil is supplied to advance the piston of the boom cylinder, and the boom is raised and lowered. In position (b), the hydraulic flow is reversed so that the boom is lowered. The boom is lowered. In addition, when the directional control valve 10 is in position (d), the hydraulic oil is supplied to the bucket cylinder (4) to move the piston forward and the bucket is lowered, while in the position (e) the hydraulic oil flow is reversed, the bucket cylinder The piston retracts and the bucket is raised. Control of the valves 10, 11 for this operation is carried out by an auxiliary control valve 9.

본 발명에 따라 예를들어 전자제어되는 스위치(12)의 출력신호에 의해 온 오프되어 보조 유압펌프(7)로 부터의 유로(13)에 제공된 방향제어밸브(14)가 제어되어 상기 유로(11)를 메인 유압펌프(6)의 유로(15)에 선택적으로 연통되게 한다. 도 3에 개략적으로 도시된 바와같이, 상기 스위치(12)는 컨트롤러(16)에 의해 제어되며, 컨트롤러(16)는 버켓실린더가 작동중인지 여부를 감지하도록 버켓실린더에 연결된 유로에 제공된 유량센서(17)의 출력신호와, 붐실린더로의 유로에 제공되어 붐실린더의 피스톤의 넓은 면에서의 압력을 감지하도록 된 압력감지센서(18)로 부터의 출력신호, 그리고 도면에 개략적으로 도시된 엔진에 통상적으로 제공된 엔진 회전속도 감지센서(19)로 부터의 출력신호를 받아 후술하는 제어방법에 따라 스위치(12)를 온오프시키도록 하는 신호를 출력한다.According to the present invention, for example, the direction control valve 14 provided on the flow path 13 from the auxiliary hydraulic pump 7 by being turned on and off by the output signal of the switch 12 which is electronically controlled is controlled so that the flow path 11 ) Is selectively communicated with the flow path 15 of the main hydraulic pump 6. As shown schematically in FIG. 3, the switch 12 is controlled by a controller 16, which is provided with a flow sensor 17 provided in a flow path connected to the bucket cylinder to detect whether the bucket cylinder is in operation. And an output signal from the pressure sensor 18 provided in the flow path to the boom cylinder to sense the pressure on the wide surface of the piston of the boom cylinder, and the engine shown schematically in the drawing. Receives an output signal from the engine speed sensor 19 provided to the output signal to turn on and off the switch 12 according to the control method described later.

본 발명에 따른 유압시스템의 제어방법은 도 4에 도시된 플로어챠트에 따라 상기 컨트롤러(16)에서 스위치(12)의 온오프를 제어함으로써 수행된다. 먼저 엔진 회전속도 감지센서(19)로 부터 감지된 엔진회전속도가 일정 속도, 바람직하기로는 1200rpm 이상인 경우, 버켓실린더(4)가 정지상태에 있는 경우 및 붐실린더(5)의 압력이 일정압력, 바람직하기로는 80kg/㎠ 이상인 경우 모두를 충족하는 경우에만 스위치(12)가 온되도록 하고 그외의 경우에는 오프되도록 제어한다.The control method of the hydraulic system according to the present invention is performed by controlling the on and off of the switch 12 in the controller 16 according to the floor chart shown in FIG. First, when the engine speed detected by the engine speed sensor 19 is a constant speed, preferably 1200 rpm or more, when the bucket cylinder 4 is at a stopped state and the pressure of the boom cylinder 5 is a constant pressure, Preferably, the switch 12 is turned on only when it satisfies all cases of 80 kg / cm 2 or more, and is turned off in other cases.

예를들어 흙을 버켓에 담아 덤프트럭에 담는 작업을 하는 경우에는 버켓실린더(4)가 작동하여 버켓(2)에 흙을 담는 작업이 완료된 상태, 즉 버켓실린더(4)가 정지상태로 된 다음 붐을 신속히 상승시키고자 하는 경우에 운전자는 가속페달을 밟아 출력을 높이게 되며 이때 엔진의 회전속도가 증가됨에 따라 보조 유압펌프의 작동에 충분한 출력이 확보되므로 붐의 신속한 상승이 가능하며 이러한 조건하에서 붐실린더의 작동을 감지하여 컨트롤러가 스위치(12)를 온시켜 보조유압펌프(6)의 토출 압유가 유로(15)로 유입되게 함으로써 붐실린더(5)로 유입되는 유량이 크게 증가되고 이로써 붐이 신속하게 상승되어 작업을 효율적으로 수행하게 된다.For example, when the soil is put into the bucket and put into the dump truck, the bucket cylinder (4) is operated to put the soil in the bucket (2) is completed, that is, the bucket cylinder (4) is stopped In order to raise the boom quickly, the driver presses the accelerator pedal to increase the output. At this time, as the engine's rotational speed is increased, sufficient power is provided for the operation of the auxiliary hydraulic pump, so that the boom can be raised quickly. By sensing the operation of the cylinder, the controller turns on the switch 12 so that the discharge pressure oil of the auxiliary hydraulic pump 6 flows into the flow path 15, thereby greatly increasing the flow rate flowing into the boom cylinder 5, thereby rapidly booming. It is raised to make the work more efficient.

본 발명에 따라 휠로다의 버켓을 이용한 작업상태에 따라 컨트롤러에 의해 전자제어 스위치를 온 오프시켜 보조 유압펌프의 작동과 방향제어밸브를 제어하여 휠로다의 작업장치, 특히 붐실린더로의 유입유량을 집중되게 제어함으로써 붐이 신속하게 상승하게 되므로 붐을 이용한 작업을 효율적으로 수행할 수 있고, 특히 엔진에 무리를 주지않고 과도한 연료소모도 방지하게 되는 장점이 있다.According to the present invention, the operation of the auxiliary hydraulic pump and the directional control valve are controlled by turning on and off the electronic control switch by the controller according to the working state using the bucket of the wheel loader to control the inflow flow into the wheel loader's working device, especially the boom cylinder. By centralized control, the boom quickly rises, so that the work using the boom can be efficiently performed, and in particular, there is an advantage in that excessive fuel consumption is avoided without overwhelming the engine.

도 1은 휠로다의 개략적인 측면도.1 is a schematic side view of a wheel loader;

도 2는 종래 휠로다 유압시스템용 유압회로도.2 is a hydraulic circuit diagram for a conventional wheel loader hydraulic system.

도 3는 본 발명에 따른 휠로다 유압시스템의 구조를 보여주는 유압회로도.Figure 3 is a hydraulic circuit diagram showing the structure of the wheel loader hydraulic system according to the present invention.

도 4는 본 발명의 유압시스템 제어방법에 따라 컨트롤러에서 스위치를 제어하는 과정을 나타내는 플로어챠트.Figure 4 is a floor chart showing a process of controlling a switch in the controller in accordance with the hydraulic system control method of the present invention.

<도면의 주요 부분에 대한 부호의 설명><Explanation of symbols for the main parts of the drawings>

1 : 휠로다 2 : 버켓 4 : 버켓실린더 5 : 붐실린더DESCRIPTION OF SYMBOLS 1 Wheel loader 2 Bucket 4 Bucket cylinder 5 Boom cylinder

6,7 : 유압펌프 8 : 메인 컨트롤 밸브장치 9 : 보조 컨트롤 밸브6,7: hydraulic pump 8: main control valve device 9: auxiliary control valve

10,11,14 : 방향제어밸브 16 : 컨트롤러 17 : 유량센서 18 : 압력감지센서 19 : 엔진 회전속도 감지센서10, 11, 14: direction control valve 16: controller 17: flow sensor 18: pressure sensor 19: engine rotational speed sensor

Claims (3)

엔진구동에 의해 작업장치의 구동에 필요한 작동유를 토출하는 메인 유압펌프(6)와 보조유압펌프(7), 상기 유압펌프들로 부터 공급되는 압유를 상기 버켓구동용 버켓실린더(4)와 붐실린더(5)로 공급하도록 제어하는 컨트롤 밸브장치(8), 상기 버켓승강을 위하여 붐을 신속하게 상승시키도록함에 요구되는 구동력을 얻기 위하여 미리 설정된 소정의 조건을 충족하는 경우에 따라 상기 보조 유압펌프의 작동을 제어하는 신호를 출력하는 스위치수단(12)과, 그에 응답하여 상기 보조유압펌프(7)로 부터 토출되는 압유의 유로를 메인 유압펌프(6)로부터 컨트롤 밸브장치(8)로의 유로에 선택적으로 연통시키도록 하는 방향제어밸브(14)와, 엔진 회전속도와 버켓실린더와 붐실린더의 동작상태에 따라 보조유압펌프를 선택적으로 구동시키도록 상기 스위치수단(12)의 온오프를 제어하는 컨트롤러(16)를 포함하여 구성되는 건설기계용 유압시스템.The main hydraulic pump 6, the auxiliary hydraulic pump 7, and the hydraulic oil supplied from the hydraulic pumps discharge the hydraulic oil necessary for driving the work device by the engine driving. The bucket cylinder 4 for the bucket driving and the boom cylinder (5) a control valve device (8) for controlling the supply of the auxiliary hydraulic pump according to a case in which predetermined conditions are set in order to obtain the driving force required to quickly raise the boom for lifting the bucket. A switch means 12 for outputting a signal for controlling operation, and a flow path of the pressurized oil discharged from the auxiliary hydraulic pump 7 in response to the flow path from the main hydraulic pump 6 to the control valve device 8; Of the switch means 12 to selectively drive the auxiliary hydraulic pump in accordance with the direction control valve 14 to communicate with the engine, and the engine rotation speed and the operating states of the bucket cylinder and the boom cylinder. Hydraulic system for a construction machine comprising a controller (16) for controlling the on and off. 제 1항에 있어서, 상기 컨트롤러(16)는 붐실린더의 압력을 감지하는 압력감지센서(18)와, 버켓실린더의 동작여부를 감지하는 유량센서(17) 및 엔진의 회전속도를 감지하는 엔진 회전속도 감지센서(19)로 부터의 출력신호들을 받아 미리 저장된 기준치와 비교하여 미리 프로그램된 바에 따라 스위치를 제어하는 신호를 출력하도록 된 것을 특징으로 하는 건설기계용 유압시스템. According to claim 1, wherein the controller (16) is a pressure sensor (18) for detecting the pressure of the boom cylinder, a flow sensor (17) for detecting the operation of the bucket cylinder and the engine rotation to detect the rotational speed of the engine Hydraulic system for a construction machine, characterized in that for receiving the output signals from the speed sensor 19 to compare the pre-stored reference value and output a signal for controlling the switch as previously programmed. 엔진 회전속도를 입력받아 미리 설정된 기준속도와 비교판단하는 제 1단계와, 상기 제 1단계에서 엔진 회전속도가 기준속도 이상인 경우 버켓실린더의 작동유무를 판별하는 제 2단계, 상기 제 2단계에서 버켓실린더가 작동중일 때 붐 실린더의 압력이 미리 설정된 기준압력 이상인지를 판별하는 제 3단계, 및 제 3단계에서 붐실린더의 압력이 미리 설정된 기준압력 이상인 경우에만 보조유압펌프로 부터 토출되는 압유를 작업장치용 유압실린더로 향하도록 스위치 스위치수단을 온시키는 제 4단계를 포함하는 건설기계용 유압시스템 제어방법.A first step of receiving an engine rotational speed and comparing with a preset reference speed; and a second step of determining whether or not the bucket cylinder is operated when the engine rotational speed is greater than or equal to the reference speed in the first step, and the bucket in the second step. The third step of determining whether the pressure of the boom cylinder is higher than the preset reference pressure when the cylinder is in operation, and the hydraulic oil discharged from the auxiliary hydraulic pump only when the pressure of the boom cylinder is higher than the preset reference pressure in the third step. And a fourth step of turning on the switch switch means to face the hydraulic cylinder for the device.
KR1019970074591A 1997-12-26 1997-12-26 Hydraulic system for construction machinery and its control method KR100473238B1 (en)

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