KR20150033934A - A Hydraulic Control System for Boom Cylinder of Construction Equipment - Google Patents

A Hydraulic Control System for Boom Cylinder of Construction Equipment Download PDF

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Publication number
KR20150033934A
KR20150033934A KR20130113835A KR20130113835A KR20150033934A KR 20150033934 A KR20150033934 A KR 20150033934A KR 20130113835 A KR20130113835 A KR 20130113835A KR 20130113835 A KR20130113835 A KR 20130113835A KR 20150033934 A KR20150033934 A KR 20150033934A
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KR
South Korea
Prior art keywords
control valve
boom
floating
boom cylinder
oil
Prior art date
Application number
KR20130113835A
Other languages
Korean (ko)
Inventor
최문규
나진규
Original Assignee
현대중공업 주식회사
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 현대중공업 주식회사 filed Critical 현대중공업 주식회사
Priority to KR20130113835A priority Critical patent/KR20150033934A/en
Publication of KR20150033934A publication Critical patent/KR20150033934A/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
    • E02F9/20—Drives; Control devices
    • E02F9/22—Hydraulic or pneumatic drives
    • E02F9/2264—Arrangements or adaptations of elements for hydraulic drives
    • E02F9/2267—Valves or distributors
    • 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
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60Y—INDEXING SCHEME RELATING TO ASPECTS CROSS-CUTTING VEHICLE TECHNOLOGY
    • B60Y2200/00—Type of vehicle
    • B60Y2200/40—Special vehicles
    • B60Y2200/41—Construction vehicles, e.g. graders, excavators
    • B60Y2200/412—Excavators

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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)

Abstract

The present invention relates to an oil-pressure control system for a boom cylinder of construction equipment characterized by including a main pump and a pilot pump; the boom cylinder connected to the main pump to move a boom in the vertical direction; a main control valve installed between the main pump and boom cylinder and controlling a supply or a discharge of oil of the main pump to/from the boom cylinder according to the upward movement or downward movement of the boom; a floating control valve switched according to whether a floating mode is turned on or off; a remote-control valve controlling a pilot pressure supply to the main control valve or the floating control valve; a flow-rate measuring means measuring the amount of lost oil of a load of the boom cylinder; and a controller turning off the floating mode by switching the floating control valve when the oil amount detected by the flow-rate measuring unit higher than a preset value lasts longer than a predetermined period. The oil-pressure control system for the boom cylinder of the construction equipment according to the present invention controls the floating mode to be turned off when the oil amount in an oil-loss passage of the load higher than the preset valve lasts longer than the preset period or the downward movement of the boom of a boom control spool lasts longer than a predetermined period even though the floating mode is on in order to jack up the construction equipment as a user desires when the user manipulates the boom to move downward to additionally jack up the equipment according to working conditions even though the floating mode is on after primarily jacking up the equipment, thereby improving the working efficiency, stability, and reliability of the construction equipment.

Description

Technical Field [0001] The present invention relates to a hydraulic control system for a boom cylinder of a construction machine,

The present invention relates to a boom cylinder hydraulic control system of a construction machine.

Construction equipment generally refers to construction civil engineering machinery, and each construction such as roads, rivers, ports, railways, and plants has a structure and performance suited to its characteristics. In other words, the construction equipment can be divided into excavation equipment, loading equipment, conveying equipment, loading equipment, compaction equipment, foundation equipment and the like due to the variety of work done in the industrial field. Specifically, the construction equipment can be classified into bulldozer, excavator, , Rollers, and the like.

The most basic work performed in the industrial field is digging. In the case of industrial construction, excavation works are mostly carried out by excavating the ground to a certain depth and installing various structures or laying pipes on the ground.

An excavator is a construction machine that carries out works such as excavation work for digging the ground in civil engineering, construction, construction site, loading work for transporting soil, crushing work for dismantling the building, suspension work for arranging the ground, And an upper revolving body mounted on the traveling body and rotated by 360 degrees and a working device.

The excavator is divided into an infinite track crawler excavator and a tire type wheel excavator according to the driving method of the traveling body. Crawler excavator is more widely used in each work site from 1 ton to more than 100 tons of equipment because it is stable and work productivity compared to wheel excavator. Wheel excavator is compared with crawler excavator It is used mainly in the work site where the work stability can be reduced but the road can be traveled and the work place can be moved without a trailer and frequently work and movement are required.

In addition, excavators can be used with appropriate working equipment depending on the state of the earth and rock, the type of work and the application. Buckets for general excavation and excavation, breakers for crushing hard ground, rocks, and crushers used for dismantling and crushing buildings.

The working mode of the excavator can be largely divided into a floating mode for planarization, a breaker mode for crushing or chopping, and a normal mode for other operations such as excavation, loading and turning.

In an excavator, a flattening operation of moving the bucket in the forward and backward directions is often performed (floating mode). In order to perform such a flattening operation, the operator must use a boom and a bucket in order to keep the load applied to the bucket constant. .

When the floating mode is set, the connection flow path between the head side chamber of the boom cylinder and the load side chamber of the rod and the return flow path to the oil tank are communicated with each other, so that the jackup of the equipment can not be performed. When the jack-up is required, the floating mode must be turned off. Therefore, there is a problem that the driver must take the inconvenience. In this case, when the equipment is jacked up with the floating mode turned off, and then the floating mode is turned on, when the boom is lowered by further jacking up the equipment according to the working conditions, The equipment is not a jack-up operation required by the driver, and the jack-down operation against the driver's intention is performed, thereby causing a risk of an accident, and reliability and competitiveness of the equipment are deteriorated.

SUMMARY OF THE INVENTION The present invention has been made in order to solve the problems of the conventional art as described above, and it is an object of the present invention to provide a boom cylinder in which, when the flow rate of the oil chamber on the rod side of the boom cylinder increases to a predetermined value or more, , The boom can be prevented from falling against the intention of the driver by making the floating mode off, thereby reducing the risk of accidents and allowing the driver to work conveniently, thereby improving the reliability and competitiveness of the equipment. And to provide a cylinder hydraulic control system.

It is another object of the present invention to provide a system and a method for operating a boom in a state where a floating mode function is turned on after a machine is jacked up, And to improve the safety and reliability of the equipment by providing the boom cylinder hydraulic control system of the boom cylinder.

A boom cylinder hydraulic control system of a construction machine according to an aspect of the present invention includes a main pump and a pilot pump; A boom cylinder connected to the main pump for driving the boom up and down; A main control valve provided between the main pump and the boom cylinder for performing supply or discharge control of the main pump to the boom cylinder in accordance with the upward or downward movement of the boom; A floating control valve that is switched on or off of the floating mode; A remote control valve for controlling the supply of pilot pressure to the main control valve or the floating control valve; A flow rate measuring means for measuring a flow rate of a load side chamber of the boom cylinder; And a controller for turning off the floating mode through the switching of the floating control valve when the flow rate detected by the flow rate measuring means exceeds a predetermined value for a predetermined time or more.

Specifically, when the floating mode is ON, the floating control valve is switched so that the head side return flow path and the rod side return flow path are communicated with each other, and when the floating mode is OFF, the head side return flow path and the rod side return flow path are communicated .

Specifically, the controller may turn off the floating mode by switching the floating control valve when a flow of the pilot pressure oil for switching the main control valve to be driven by the fall of the boom is sensed.

Specifically, the flow rate measuring means may be installed at an upper portion of the rod-side flow passage connected to the rod-side oil chamber.

The boom cylinder hydraulic pressure control system of the construction machine according to the present invention is characterized in that when the flow rate of the load side oil path is increased beyond a predetermined value by a predetermined time or when the operation of lowering the boom is continued for a certain period of time, By controlling the floating mode to be off even in the on state, even if the floating function is turned on after the equipment is jacked up, the boom can be lowered and manipulated according to the working conditions. Up operation required by a worker is performed, the workability, stability, and reliability of the equipment can be improved.

1 is a side view of a construction machine according to the present invention.
2 is a hydraulic circuit diagram of a boom cylinder hydraulic control system of a conventional construction machine.
3 is a hydraulic circuit diagram of a boom cylinder hydraulic control system of a construction machine according to an embodiment of the present invention.

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

1 is a side view of a construction machine according to the present invention.

1, the construction machine 1 according to the present invention includes a crawler type lower traveling body 1a, an upper revolving body 1b, a front attachment 1c, a boom 1d, an arm 1e, A bucket 1f, and a boom cylinder 12. As shown in Fig.

The construction machine 1 according to the present invention comprises a crawler type lower traveling body 1a, an upper revolving body 1b supported by a crawler type lower traveling body 1a in a revolving manner, and an upper revolving body 1b mounted on the upper revolving body 1b The front attachment 1c includes a boom 1d which is supported by the upper swivel body 1b in a vertically movable manner and an arm 2b which is supported by the back and forth movable member on the end of the boom 1d. Such as a bucket 1f, a breaker (not shown), and a creem shell (not shown), which are installed at the ends of the arm 1e and the arm 1e, respectively.

Further, the construction machine 1 according to the present invention is not limited to an excavator (not shown), and may be equipments required for various other constructions.

2 is a hydraulic circuit diagram of a boom cylinder hydraulic control system of a conventional construction machine.

2, the boom cylinder hydraulic control system 2 of the conventional construction machine includes a main pump 10, a pilot pump 11, a boom cylinder 12, a main control valve 13, a remote control The valve 14, the floating control valve 17, the first solenoid valve 18, the second solenoid valve 19, the oil tank 20, the rod-side flow passage 21, the rod- Side flow path 22, and a head side return flow path 22a.

The boom cylinder hydraulic control system 2 of the conventional construction machine must turn off the floating mode when the jack-up is required according to the working conditions in the floating mode, so that the driver is liable to inconvenience. Also, when the boom is lowered and operated by jacking up the equipment more in accordance with the working conditions in the floating mode, there is a danger that the jack-down operation against the driver's intention occurs, thereby causing an accident and lowering the reliability and competitiveness of the equipment.

3 is a hydraulic circuit diagram of a boom cylinder hydraulic control system of a construction machine according to an embodiment of the present invention.

3, the boom cylinder hydraulic control system 3 of the construction machine according to the embodiment of the present invention includes a main pump 10, a pilot pump 11, a boom cylinder 12, The first solenoid valve 18, the second solenoid valve 19, the oil tank 20, the first solenoid valve 18, the second solenoid valve 19, the second solenoid valve 13, the remote control valve 14, the controller 15, the flow rate measuring means 16, the floating control valve 17, A rod-side return passage 21a, a head-side passage 22, and a head-side return passage 22a. In the embodiment of the present invention, the main pump 10, the pilot pump 11, the boom cylinder 12, the main control valve 13, the remote control valve 14, the floating control valve 17, the first solenoid valve The second solenoid valve 19, the oil tank 20, the rod-side passage 21, the rod-side return passage 21a, the head-side passage 22 and the head- The same reference numerals are used for the respective components and constructions in the boom cylinder hydraulic control system (2) of the construction machine, but they are not necessarily denoted by the same reference numerals.

The boom cylinder 12 is connected to the main pump 10 to drive the boom 1d up and down. The boom cylinder 12 can be constituted by the head side oil chamber 12b and the rod side oil chamber 12a and the pressure oil of the main pump 10 is supplied to the head side oil chamber 12b, The boom cylinder 12 is extended and the pressurized oil from the main pump 10 is supplied to the rod side oil chamber 12a and the pressurized oil from the head side oil chamber 12b is supplied to the oil tank 20, The boom cylinder 12 is contracted.

The main control valve 13 is provided between the main pump 10 and the boom cylinder 12 and supplies or discharges the main oil pump 10 to the boom cylinder 12 as the boom is raised or lowered Control is performed. The main control valve 13 may be composed of a three-position switching valve and may be composed of three ports.

When the boom 1d is raised or lowered by a control unit (not shown), the main control valve 13 receives or exits the pilot pressure from the remote control valve 14 to be described later, .

The remote control valve 14 controls the supply of the pilot pressure to the main control valve 13 or a floating control valve 17 to be described later. The remote control valve 14 can send a signal to the controller 15 when the pilot pressure is applied for a predetermined time so that the floating mode is on and the boom 1d descent to the main control valve 13 is manipulated.

The remote control valve 14 transmits a signal to the floating control valve 17 to cause the head side return flow path 22a and the rod side return flow path 21a to communicate with each other when receiving a signal to turn off the floating mode from the controller 15. [ So as not to communicate with each other.

When the flow rate detected by the flow rate measuring means 16, which will be described later, is not less than a predetermined value and continues for a predetermined time or longer, the controller 15 controls the flow rate of the fluid to be supplied to the floating control valve 17, the first solenoid valve 18, And the floating mode is turned off through the switching of the valve 19. [ Further, even when the flow of the pilot pressure oil for switching the main control valve 13 to be driven by the descent of the boom 1d is sensed, the floating mode can be turned off by switching the floating control valve 17. In this case, a sensing means (not shown) for sensing the descent of the boom 1d may be provided.

Specifically, the controller 15 determines that the remote control valve 14 is applying the pilot pressure to the main control valve 13 for a certain time so as to operate the boom 1d descent from the floating mode to the main control valve 13 It is possible to receive a signal from the remote control valve 14. Further, the controller 15 can receive a signal that the flow rate of the rod-side oil chamber 12a from the flow rate measuring means 16 to be described later is maintained at a predetermined value or more for a certain period of time. The controller 15 receiving this signal can again transmit a signal to the remote control valve 14 to turn off the floating mode.

The flow rate measuring means 16 measures the flow rate of the load side oil chamber 12a of the boom cylinder 12. The flow rate measuring means 16 may be installed above the rod-side flow passage 21 connected to the rod-side oil chamber 12a. The flow rate measuring means 16 can transmit a signal to the controller 15 when the detected flow rate is maintained at a predetermined value or more for a predetermined period of time and the value of the predetermined flow rate is the flow rate of the pressurized fluid flowing into the load side chamber 12a It may be a value that causes the boom cylinder 12 to be shrunk to cause a sufficient descent of the boom 1d. For example, the flow rate value is such that the load side oil chamber 12a is extended more than half in the boom cylinder 12, and the predetermined time is, for example, about 0.5 sec.

The floating control valve 17 is switched in accordance with the on or off of the floating mode. Specifically, when the floating mode is ON, the floating control valve 17 is switched so that the head side return passage 22a and the rod side return passage 21a are communicated with each other. When the floating mode is OFF, the head side return passage 22a And the rod side return oil passage 21a are not communicated with each other.

The floating control valve 17 can receive the pilot pressure of the remote control valve 14, which receives the signal from the controller 15, and can turn the floating mode on or off.

The first solenoid valve 18 is disposed between the opening position for opening the head side return passage 22a and the pressure oil for the head side oil chamber 12b so that the pressure oil in the head side oil chamber 12b can be discharged to the oil tank 20, Position switching valve for switching the closing position for closing the head-side returning flow path 22a so as not to be discharged to the tank 20.

The second solenoid valve 19 is provided at the open position where the rod side return oil passage 21a is opened so that the pressurized oil in the rod side oil chamber 12a can be discharged to the oil tank 20, And a two-position switching valve for switching a closing position for closing the rod-side return flow passage 21a so as not to be discharged to the tank 20. [

As described above, in the present embodiment, when the flow rate of the load-side oil chamber of the boom cylinder 12 exceeds the set value for a predetermined time or more, the floating mode is turned off even if the floating mode is On, By preventing the boom 1d from descending against the doctor, the risk of accidents can be reduced and the operator can work conveniently, thereby improving the reliability and competitiveness of the equipment. Further, in a state where the floating mode function is turned on after the equipment is jacked up, the jacking up operation required by the driver is performed when the boom 1d is lowered by further jacking up the equipment according to the operation Thereby improving the safety and reliability of the equipment.

1: Construction machine 2 of the present invention: Conventional construction machine hydraulic control system
3: Construction machine hydraulic control system 1a of the present invention: Crawler type lower traveling body
1b: upper swivel body 1c: front attachment
1d: Boom 1e: Cancer
1f: bucket 10: main pump
11: Pilot pump 12: Boom cylinder
12a: Loss on the rod side 12b: Loss on the head side
13: Main control valve 14: Remote control valve
15: controller 16: flow measuring means
17: Floating control valve 18: First solenoid valve
19: second solenoid valve 20: oil tank
21: rod-side flow path 21a: rod-
22: head side oil passage 22a: head side return oil passage

Claims (4)

Main pump and pilot pump;
A boom cylinder connected to the main pump for driving the boom up and down;
A main control valve provided between the main pump and the boom cylinder for performing supply or discharge control of the main pump to the boom cylinder in accordance with the upward or downward movement of the boom;
A floating control valve that is switched on or off of the floating mode;
A remote control valve for controlling the supply of pilot pressure to the main control valve or the floating control valve;
A flow rate measuring means for measuring a flow rate of a load side chamber of the boom cylinder; And
And a controller for turning off the floating mode through the switching of the floating control valve when the flow rate detected by the flow rate measuring means exceeds a preset value for a predetermined time or longer. . The apparatus of claim 1, wherein the floating control valve comprises:
When the floating mode is on, switching is made so as to communicate the head side return passage and the rod side return passage, and when the floating mode is off, the head side return passage and the rod side return passage are switched so as not to communicate with each other Mechanical boom cylinder hydraulic control system. 2. The apparatus of claim 1,
Wherein when the flow of the pilot pressure oil for switching the main control valve to be driven by the falling of the boom is sensed, the floating mode is turned off by switching the floating control valve. . The apparatus according to claim 1,
Side flow path connected to the load-side oil chamber.
KR20130113835A 2013-09-25 2013-09-25 A Hydraulic Control System for Boom Cylinder of Construction Equipment KR20150033934A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
KR20130113835A KR20150033934A (en) 2013-09-25 2013-09-25 A Hydraulic Control System for Boom Cylinder of Construction Equipment

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Application Number Priority Date Filing Date Title
KR20130113835A KR20150033934A (en) 2013-09-25 2013-09-25 A Hydraulic Control System for Boom Cylinder of Construction Equipment

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR20220119907A (en) 2021-02-22 2022-08-30 고재필 Hydraulic system for aerial work vehicles with the function of preheating the boarding box

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5447094A (en) * 1994-02-07 1995-09-05 Delta Power Hydraulic Co. Hydraulic system for bucket self-leveling during raising and lowering of boom
KR20040093891A (en) * 2003-04-30 2004-11-09 볼보 컨스트럭션 이키프먼트 홀딩 스웨덴 에이비 hydraulic circuit of having boom float position
JP2010084330A (en) * 2008-09-29 2010-04-15 Kubota Corp Float control system of utility machine
KR20100056087A (en) * 2008-11-19 2010-05-27 두산인프라코어 주식회사 Boom cylinder control circuit for construction machinery
US20130220425A1 (en) * 2012-02-27 2013-08-29 Paul Edward Pomeroy Flow sensing based variable pump control technique in a hydraulic system with open center control valves

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5447094A (en) * 1994-02-07 1995-09-05 Delta Power Hydraulic Co. Hydraulic system for bucket self-leveling during raising and lowering of boom
KR20040093891A (en) * 2003-04-30 2004-11-09 볼보 컨스트럭션 이키프먼트 홀딩 스웨덴 에이비 hydraulic circuit of having boom float position
JP2010084330A (en) * 2008-09-29 2010-04-15 Kubota Corp Float control system of utility machine
KR20100056087A (en) * 2008-11-19 2010-05-27 두산인프라코어 주식회사 Boom cylinder control circuit for construction machinery
US20130220425A1 (en) * 2012-02-27 2013-08-29 Paul Edward Pomeroy Flow sensing based variable pump control technique in a hydraulic system with open center control valves

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR20220119907A (en) 2021-02-22 2022-08-30 고재필 Hydraulic system for aerial work vehicles with the function of preheating the boarding box

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