KR20170046356A - A Hydraulic Control Device for Construction Equipment - Google Patents

A Hydraulic Control Device for Construction Equipment Download PDF

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Publication number
KR20170046356A
KR20170046356A KR1020150146576A KR20150146576A KR20170046356A KR 20170046356 A KR20170046356 A KR 20170046356A KR 1020150146576 A KR1020150146576 A KR 1020150146576A KR 20150146576 A KR20150146576 A KR 20150146576A KR 20170046356 A KR20170046356 A KR 20170046356A
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KR
South Korea
Prior art keywords
engine
pump
rpm
horsepower
horsepower per
Prior art date
Application number
KR1020150146576A
Other languages
Korean (ko)
Inventor
김범수
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 KR1020150146576A priority Critical patent/KR20170046356A/en
Publication of KR20170046356A publication Critical patent/KR20170046356A/en

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    • 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
    • B66—HOISTING; LIFTING; HAULING
    • B66F—HOISTING, LIFTING, HAULING OR PUSHING, NOT OTHERWISE PROVIDED FOR, e.g. DEVICES WHICH APPLY A LIFTING OR PUSHING FORCE DIRECTLY TO THE SURFACE OF A LOAD
    • B66F9/00—Devices for lifting or lowering bulky or heavy goods for loading or unloading purposes
    • B66F9/06—Devices for lifting or lowering bulky or heavy goods for loading or unloading purposes movable, with their loads, on wheels or the like, e.g. fork-lift trucks
    • B66F9/075—Constructional features or details
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B66—HOISTING; LIFTING; HAULING
    • B66F—HOISTING, LIFTING, HAULING OR PUSHING, NOT OTHERWISE PROVIDED FOR, e.g. DEVICES WHICH APPLY A LIFTING OR PUSHING FORCE DIRECTLY TO THE SURFACE OF A LOAD
    • B66F9/00—Devices for lifting or lowering bulky or heavy goods for loading or unloading purposes
    • B66F9/06—Devices for lifting or lowering bulky or heavy goods for loading or unloading purposes movable, with their loads, on wheels or the like, e.g. fork-lift trucks
    • B66F9/075—Constructional features or details
    • B66F9/20—Means for actuating or controlling masts, platforms, or forks
    • B66F9/22—Hydraulic devices or systems
    • 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
    • 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
    • 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
    • E02F9/2246—Control of prime movers, e.g. depending on the hydraulic load of work tools
    • 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
    • F15B15/00—Fluid-actuated devices for displacing a member from one position to another; Gearing associated therewith
    • F15B15/18—Combined units comprising both motor and pump
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/20—Fluid pressure source, e.g. accumulator or variable axial piston pump
    • F15B2211/205—Systems with pumps
    • F15B2211/20507—Type of prime mover

Abstract

The present invention relates to a hydraulic control system for construction equipment, which comprises: an operation device operated by pressure oil; a pump operated by an engine, and supplying the pressure oil to the operation device; a driving device operated by the engine for construction equipment to be operated and moved back and forth; and a control unit controlling a discharge flow rate of the pump. The control unit calculates pump allowance consumption horsepower per RPM of the engine through the maximally generating horsepower per RPM of the engine and consumption horsepower of the driving device per RPM of the engine, and controlling the pump under the pump allowance consumption horsepower per RPM of the engine.

Description

[0001] Hydraulic Control Device for Construction Equipment [0002]

The present invention relates to a hydraulic control system for 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.

In addition to the excavator, the construction machine has a front device including a boom and a bucket in front of the main body. It can be used to load aggregate such as crushed rocks and soil, to transport hay, garbage, Wheel loaders, and forklifts that are used to raise or transport heavy loads.

These forklifts and wheel loaders have a stall phenomenon momentarily between high-power operations such as overloading (traveling + maximum load water rise or workpiece digging) in the low RPM section due to the torque characteristics of the engine , Which is not compatible with the horsepower control method of the piston pump.

Therefore, since the forklift and the wheel loader start work in the low RPM section, there is a problem that it is difficult to improve when the torque change of the engine is impossible.

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above problems of the prior art, and it is an object of the present invention to provide an engine stall control system, And to provide a hydraulic control system of a construction machine for preventing the occurrence of such a problem.

A hydraulic control system for a construction machine according to an aspect of the present invention includes: a drive device that operates via a pressurized oil; A pump driven by the engine and supplying pressurized oil to the drive device; A traveling device driven by the engine and operated so as to move the construction machine back and forth; And a control unit for controlling a discharge flow rate of the pump, wherein the control unit calculates the pump allowable consumption horsepower per engine RPM through the maximum generated horsepower per RPM of the engine and the driving unit consumed horsepower per RPM of the engine And the pump is controlled to be equal to or less than the pump allowable consumption horsepower per engine RPM.

Specifically, the control unit can calculate the pump allowable consumption horsepower per engine RPM by the following equation (1). Wherein Ma is a maximum generated horsepower per RPM of the engine, Mb is the driving device consumed horsepower per RPM of the engine, Mc is the pump allowable horsepower per the engine RPM,

Specifically, the traveling device may include a torque converter that converts the horsepower supplied from the engine to the forward and backward propulsion force of the construction machine.

Specifically, the maximum generated horsepower per RPM of the engine is the horsepower at which the stall phenomenon of the engine occurs, and the maximum consumed horsepower among the driving apparatus consumed horsepower per RPM of the engine is the horsepower at which the stall phenomenon of the torque converter occurs .

Specifically, the control unit can control the discharge flow rate of the pump to be equal to or smaller than the maximum discharge flow rate of the pump by the following expression (2). Where Qm is the maximum discharge flow rate of the pump, Mc is the pump allowable consumption horsepower per the engine RPM, and P is the discharge pressure of the pump.

Specifically, the control unit may include an EPPR valve for controlling the discharge flow rate of the pump with an electrical signal.

The hydraulic control system of a construction machine according to the present invention prevents a start-off (engine stall phenomenon) even in a low RPM section (low torque, low power) under overload work conditions of a construction machine, So that the work efficiency of the worker is improved and the working period is reduced.

1 is a side view of a wheel loader including a hydraulic control system of the present invention.
2 is a side view of a forklift including a hydraulic control system of the present invention.
3 is a conceptual diagram showing a hydraulic control system of a construction machine of the present invention.
4 is a graph showing an engine-torque converter matching curve.

BRIEF DESCRIPTION OF THE DRAWINGS The objects, particular advantages and novel features of the present invention will become more apparent from the following detailed description taken in conjunction with the accompanying drawings, in which: FIG. It should be noted that, in the present specification, the reference numerals are added to the constituent elements of the drawings, and the same constituent elements are assigned the same number as much as possible even if they are displayed on different drawings. In the following description, well-known functions or constructions are not described in detail since they would obscure the invention in unnecessary detail.

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

Fig. 1 is a side view of a wheel loader including a hydraulic control system of the present invention, and Fig. 2 is a side view of a forklift including a hydraulic control system of the present invention. Hereinafter, the wheel loader 1 or the forklift 2 having the hydraulic control system 20 according to the embodiment of the present invention will be described first with reference to Figs. 1 and 2. Fig. Here, the wheel loader 1 or the forklift 2 shown in Figs. 1 and 2 is only one example for illustrating the hydraulic control system 20 according to the embodiment of the present invention, and is not limited thereto.

As shown in Fig. 1, the wheel loader 1 is a construction machine that carries out operations such as a loading operation for loading aggregates such as crushed rock mass, soil and the like, or a transportation operation for transporting such materials at a short distance, A wheel loader main body 30, and a traveling device 40. [

The working device 10 is provided at one side of the wheel loader 1 and comprises a bucket 12 and a boom 15. The boom 15 is operated by a boom cylinder 14, The bucket cylinder 11 and the loader linkage 13 can perform detailed operations.

For example, when the bucket cylinder 11 is compressed, the loader linkage 13 is rotated in the direction of the bucket 12, so that the end of the bucket 12 is moved forward. When the bucket cylinder 11 is tensioned, (13) is rotated in a direction opposite to the bucket (12), i.e., inside the bucket (12), so that the gravel or the like can be contained in the internal space.

Specifically, when the boom cylinder 14 is compressed, the boom 15 is rotated downward to move the bucket 12 toward the ground. As the end of the bucket 12 comes into contact with the ground due to the compression of the bucket cylinder 11, Ready state.

Thereafter, the bucket cylinder 11 is pulled to load aggregate such as crushed rock mass, soil and the like into the bucket 11, and the traveling device 40 to be described later is driven to move to an unloading place of the aggregate do. At this time, the bucket 11 can be moved to the unloading position while being positioned close to the ground. In a state where the bucket 11 is lifted from the ground by pulling the boom cylinder 14 and raising the boom 15 You can also move to an unloading location.

Here, a quick coupler is used for connecting or disconnecting the bucket 12 to the front portion of the boom 15. The quick coupler is installed in the form of a cylinder (not shown) on the front surface of the boom 15 in order to quickly and easily move the bucket 12 and the boom 15 together. In addition, the quick coupler receives the pressurized oil from the pressurized oil storage tank 21 mounted inside the wheel loader body 30 to be described later and inserts or separates the cylinder described above. The cylinder is inserted into the bucket 12 The buckets 12 are inserted into or detached from the protruded brackets (not shown), thereby detaching and attaching the buckets 12.

The wheel loader main body 30 includes a driving unit 31, a counterweight 32, and an engine 33, which are connected to the front portion of the work unit 10 and mounted on the driving unit 40 so as to be movable. .

The operating room 31 is provided with various operating devices that can operate the wheel loader 1 by a worker (not shown) such as a work device operating portion (not shown) and a traveling operating portion (not shown). A plurality of levers or switches that can respectively operate the detailed configuration of the working device 10 can be provided in the working device operating portion. The traveling operating portion includes an accelerator pedal and a brake pedal for operating the traveling device 40, And a plurality of traveling levers for adjusting the front, rear, left, and right directions.

The traveling device 40 serves as a moving part of the equipment. The traveling device 40 is located at the lower part of the main body 30 and has front and rear right and left front wheel wheels 42 rotatably installed on the front side. As shown in FIG.

2, the forklift 2 is a construction machine for carrying out operations such as a lifting operation for lifting a heavy load 80 and a transportation operation for transporting the load 80 to a loading site. The forklift main body 50, (60), and a traveling device (70).

The forklift 2 may have a lift cylinder (not shown) and a tilt cylinder (not shown) for driving the steering assist device (not shown), the traveling device 70 and the mast assembly 60.

The forklift main body 50 may include a driving room 51 and an engine (not shown), which are mounted on the traveling device 70, to which a mast assembly 60 is connected.

The operation room 51 is provided with various operation devices that can operate the forklift 2 by an operator (not shown) such as a mast assembly operation portion (not shown) and a travel operation portion (not shown). The mast assembly operation portion may be provided with a plurality of levers or switches for respectively operating the detailed configuration of the mast assembly 60. The mast assembly operation portion includes an accelerator pedal and a brake pedal for operating the traveling device 70, And a plurality of traveling levers for adjusting the front and rear left and right directions.

An overhead guard 511 for protecting a driver (not shown) boarding the cab 51 is provided on the upper side of the cab 51.

A quick coupler is used for connecting or disconnecting the forklift main body 50 with the mast assembly 60 at the front portion.

The quick coupler is installed in the form of a cylinder (not shown) on the front surface of the forklift main body 50 in order to facilitate quick and easy detachment and attachment of the forklift main body 50 and the mast assembly 60. In addition, the quick coupler is configured such that the pressurized oil is supplied from the pressurized oil storage tank 21 mounted in the inside of the forklift main body 50, and the cylinder described above is inserted or removed. When the cylinder is projected to the bucket 12 The bucket 12 is inserted and removed in a bracket (not shown), thereby detaching and attaching the bucket 12.

The mast assembly 60 has a carriage 62 capable of elevating up and down along the mast rails 61 and the mast rails 61 and a pair of forks 63 Is mounted so as to be adjustable in space.

The front wheel 71 and the rear wheel 72 included in the traveling device 70 and the traveling device 70 are the same as or similar to the traveling device 40 described in the wheel loader 1 shown in Fig. do.

Hereinafter, the hydraulic control system 20 of the construction machine of the present invention for driving the wheel loader 1 or the forklift 2 will be described with reference to FIG.

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

3, the hydraulic control system 20 of the construction machine according to the present invention includes a pressure oil storage tank 21, a pump 22, a traveling unit 23, a main control valve 24, A unit 25, a control unit 26, and an engine 33. [

The pressurized oil storage tank 21 is connected to a drive unit 25 mounted on the construction machine 1 or 2 through a pressure line (not shown) and pumps the stored pressure oil to the hydraulic devices 22).

The pressurized oil storage tank 21 may be in the form of a pressure vessel for storing the compressible fluid, and the compressible fluid used in the drive unit 25 may be recovered again, filtered and then restored.

The pressurized oil storage tank 21 can store only a certain level of the compressible fluid so that a constant volume of void space is formed in the pressurized oil storage tank 21 in order to supply, recover and store the stored compressible fluid. This is because when the pressurized oil storage tank 21 completely stores the compressible fluid, the compressible fluid can not be recovered to the pressurized oil storage tank 21 at any moment when it is recovered more than the amount of supplying the compressible fluid, This is because it can happen.

The pump 22 is provided on a pressurization line (not shown) between the pressurized oil storage tank 21 and the main control valve (MCV) 24 and receives power (or horsepower) by the engine 33 And supplies the pressurized oil stored in the pressurized oil storage tank (21) to the main control valve (24). Here, the discharge amount of the pump 22 can be changed by a swash plate (not shown) with a variable displacement pump.

The pump 22 receives a control signal from a control unit 26 to be described later by wire or wireless and can control the discharge flow rate and can transmit the discharge flow rate value of the pump 22 to the control unit 26 by wire or wirelessly have.

The traveling unit 23 can perform the forward or backward movement of the construction machine 1, 2. Specifically, the driving unit 23 is mechanically and parallelly connected to the engine 33 via a gear (not shown) and receives power (or horsepower) generated by the engine 33, ). ≪ / RTI >

The traveling unit 23 is a transmission mechanism that transmits a rotational force, which is power (or horsepower), supplied from a transmission (not shown) that changes the travel of the construction machines 1 and 2 to forward, (Not shown) and front wheels 42, 72 and rear wheels 41, 71, which convert the driving force to the driving force of the first and second wheels 1, 2.

The main control valve 24 supplies the pressure oil supplied from the pump 22 to the drive unit 25.

Specifically, when the construction machine 1 or 2 lifts the cargo 80 or performs operations such as earth moving or general excavation, the main control valve 24 distributes the hydraulic oil to the devices performing the respective operations In this way, pressure can be concentrated on each work, and the construction machine (1, 2) can perform each work.

The drive unit 25 can supply the pressurized oil from the pump 22 to lift the cargo 80 or carry out operations such as earth moving or general excavation.

More specifically, the drive unit 25 includes a mast assembly 60 for lifting and moving the cargo 80, a bucket 12 for carrying out operations such as earth moving or general excavation, a loader linkage 13, A boom cylinder 14 and a boom 15. In order to drive the boom cylinder 14 and the boom 15, pressurized oil may be supplied from the pump 22 to drive the respective drive units through pressurized oil.

The control unit 26 calculates the pump margin consumption per RPM of the engine 33 through the maximum generated horsepower per RPM of the engine 33 and the horsepower consumption per RPM of the engine 33, The pump 22 is controlled to be equal to or lower than the pump margin consumed horsepower per RPM.

Hereinafter, FIG. 4 is referred to in order to explain a procedure for calculating the pump allowable consumption horsepower, which is a value for controlling the pump 22, and FIG. 4 is a graph showing the engine-torque converter matching curve .

In the graph, T is the torque curve curve of the engine 33, F / R is the curve curve of the torque converter generated at the forward and rearward of the construction machine 1, 2, S is a point at which the torque converter causes a running stall to a point at which the torque curve curve of the engine 33 and the curve curve of the torque converter generated at the time of forward and backward of the construction machine 1 and 2 match.

x is the pump margin consumed horsepower at any RPM of the engine 33, y is the horsepower consumption horsepower of the construction machine 1 or 2 at any RPM of the engine 33, z is the arbitrary This represents the horsepower consumption of the construction machine (1, 2) at neutral in RPM.

The control unit 26 can calculate the pump margin consumed horsepower per RPM of the engine 33 through the calculation formula 1. Ma = Mb = Mc (Ma is the maximum generated horsepower per RPM of the engine 33, Mb And Mc is the pump margin consumed horsepower per RPM of the engine 33)

Referring to the graph shown in FIG. 4, Ma represents the value of x + y at any RPM of the engine 33, and Mb represents y. Therefore, it can be seen that the pump margin consumed horsepower per RPM of the engine 33 is x. Therefore, the control unit 26 can control the pump 22 to consume power within the range of x when the discharge flow rate of the pump 22 is controlled.

At this time, the control unit 26 can receive the RPM information from the engine 33 in real time, wired or wirelessly, and can receive the consumed horse power from the traveling devices 40 and 70 by wire or wirelessly. Here, the maximum generated horsepower Ma per RPM of the engine 33 is the horsepower at which the stall phenomenon of the engine 33 occurs, and the maximum consumed horsepower among the driving unit consumed horsepower Mb per RPM of the engine 33 is Stall is the horsepower at which the phenomenon occurs.

The control unit 26 can calculate the pump allowable consumption horsepower Mc per RPM of the engine 33 in the calculation formula 1 and calculate the pump allowable consumption horsepower Mc per RPM of the engine 33 based on the pump allowable consumption horsepower Mc per the calculated RPM 33 of the engine 33 22), and the equation 2 is Qm = Mc / P. (Where Qm is the maximum discharge flow rate of the pump 22, Mc is the pump margin consumed horsepower per RPM of the engine 33, and P is the discharge pressure of the pump 22)

At this time, the control unit 26 can receive the discharge pressure from the pump 22 by wire or wirelessly.

The control unit 26 can finally calculate the maximum discharge flow rate Qm of the pump 22 through the calculation equations 1 and 2 and calculate the maximum discharge flow rate Qm of the pump 22 to be less than the calculated maximum discharge flow rate Qm of the pump 22. [ Can be controlled. At this time, the control unit 26 controls the swash plate of the pump 22 by an electric signal through an EPPR valve (not shown) to control the discharge flow rate of the pump 22 proportionally.

As described above, in the present invention, the margin horsepower of the pump 22 can be calculated through the maximum horsepower per RPM of the engine 33 through the control unit 26, and within the margin horsepower of the calculated pump 22, The stall phenomenon of the engine 33 can be effectively prevented by controlling the excess horsepower of the pump 22 in operation.

The engine 33 is driven by supplying fuel such as diesel or the like to generate power, and can supply the generated power to the pump 22 or the traveling unit 23. At this time, the engine 33 may be directly connected to the pump 22, and may be configured to be connected in series with each other. Further, a separate shaft (not shown) having a gear (not shown) separate from the driving unit 23 (Not shown).

Therefore, the engine 33 can transmit the generated power to not only the pump 22 but also the driving unit 23, and the driving unit 23 converts the power received from the engine 33 into torque, (1, 2).

As described above, the hydraulic control system of the construction machine according to the present invention prevents the start-off (engine stall phenomenon) even in the low RPM section (low torque, low power) under the overload work condition of the construction machine, The work can be smoothly performed, the work efficiency of the worker is improved, and the working period is reduced.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the same is by way of illustration and example only and is not to be construed as limiting the present invention. It is obvious that the modification and the modification are possible.

It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

1: Wheel Loader 2: Forklift
10: working device 11: bucket cylinder
12: Bucket 13: Loader Linkage
14: Boom cylinder 15: Boom
20: Hydraulic control system 21 of the present invention: Pressurized oil storage tank
22: Pump 23: Driving unit
24: main control valve 25: drive unit
26: control unit 30: wheel loader main body
31: cab 32: counterweight
33: engine 40: traveling device
41: rear wheel 42: front wheel
50: Forklift main body 51: Cab
511: Overhead guard 512: Pedal
60: mast assembly 61: mast rail
62: carriage 63: fork
70: traveling device 71: front wheel
72: rear wheel 80: cargo
T: Torque curve F / R: Front and rear curve
N: Neutral curve S: Driving stall point
x: pump margin per RPM engine RPM horsepower
y: Driving unit consumption horsepower per engine RPM in front and rear
z: Drive horsepower per neutral RPM engine RPM

Claims (6)

A drive device which operates via pressure oil;
A pump driven by the engine and supplying pressurized oil to the drive device;
A traveling device driven by the engine and operated so as to move the construction machine back and forth; And
And a control unit for controlling a discharge flow rate of the pump,
Wherein,
Calculating the pump allowable consumption horsepower per engine RPM through the maximum generated horsepower per RPM of the engine and the driving unit consumed horsepower per RPM of the engine and controlling the pump to be less than the pump allowable consumption horsepower per engine RPM And the hydraulic control system of the construction machine. The apparatus of claim 1,
And calculates the pump allowable consumption horsepower per engine RPM by the following equation (1).

Wherein Ma is a maximum generated horsepower per RPM of the engine, Mb is the driving device consumed horsepower per RPM of the engine, Mc is the pump allowable horsepower per the engine RPM, The traveling device according to claim 2,
And a torque converter that converts the horsepower supplied from the engine to the forward and backward propulsion force of the construction machine. The method of claim 3,
The maximum generated horsepower per RPM of the engine is the horsepower at which the stall phenomenon of the engine occurs,
Wherein the maximum consumed horsepower of the driving unit consumed horsepower per RPM of the engine is the horsepower at which the stall phenomenon of the torque converter is generated. 5. The apparatus of claim 4,
And the discharge flow rate of the pump is controlled to be equal to or less than a maximum discharge flow rate of the pump by the following equation (2).

Where Qm is the maximum discharge flow rate of the pump, Mc is the pump allowable consumption horsepower per the engine RPM, and P is the discharge pressure of the pump. 6. The apparatus of claim 5,
And an EPPR valve for controlling the discharge flow rate of the pump by an electrical signal.
KR1020150146576A 2015-10-21 2015-10-21 A Hydraulic Control Device for Construction Equipment KR20170046356A (en)

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Application Number Priority Date Filing Date Title
KR1020150146576A KR20170046356A (en) 2015-10-21 2015-10-21 A Hydraulic Control Device for Construction Equipment

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR101970436B1 (en) * 2018-08-14 2019-04-18 박헌정 Multipurpose Construction Vehicle for Inclined Shaft of Underground Tunnel
KR20190050491A (en) * 2017-11-03 2019-05-13 현대건설기계 주식회사 Engine control system and method for working machine

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR20190050491A (en) * 2017-11-03 2019-05-13 현대건설기계 주식회사 Engine control system and method for working machine
KR101970436B1 (en) * 2018-08-14 2019-04-18 박헌정 Multipurpose Construction Vehicle for Inclined Shaft of Underground Tunnel

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