EP3222784A1

EP3222784A1 - Apparatus for controlling hydraulic circuit of construction equipment

Info

Publication number: EP3222784A1
Application number: EP15861005.5A
Authority: EP
Inventors: Young Sik Cho
Original assignee: Doosan Infracore Co Ltd
Current assignee: HD Hyundai Infracore Co Ltd
Priority date: 2014-11-20
Filing date: 2015-11-18
Publication date: 2017-09-27
Also published as: WO2016080760A1; KR102088091B1; CN107002390A; EP3222784A4; KR20170091115A

Abstract

The present disclosure relates to an apparatus for controlling a hydraulic circuit of construction equipment. According to the apparatus for controlling a hydraulic circuit of construction equipment according to the exemplary embodiment of the present disclosure, a flow rate of a first pump may be provided early to a front working apparatus when traveling and working are required at the same time, and as a result, it is possible to advance a point in time at which the front working apparatus actually begins to operate. In addition, according to the apparatus for controlling a hydraulic circuit of construction equipment according to the exemplary embodiment of the present disclosure, it is possible to mitigate an impact caused by a reduction in traveling speed by controlling a spool of a control valve 20 in accordance with a control map.

Description

[Technical Field]

The present disclosure relates to an apparatus for controlling a hydraulic circuit of construction equipment, and more particularly, to an apparatus for controlling a hydraulic circuit of construction equipment which is capable of mitigating an impact caused by a change in flow rate when traveling and font working are performed at the same time.

[Background Art]

In general, construction equipment includes a hydraulic circuit apparatus and a working apparatus. The hydraulic circuit apparatus includes an operating unit, a control valve, a pump, and an actuator. For example, in the case of an excavator among the construction equipment, there are a boom structure, an arm structure, a bucket structure, and an option apparatus as the working apparatus.
As the operating unit, a joystick, a pedal, and the like are provided in a driver seat. A main control valve provides the actuator with a working fluid corresponding to an operation displacement of the joystick. The pump may include a first pump and a second pump, and the first and second pumps pressurize the working fluid and provide the working fluid to the main control valve. The actuator is operated by the provided working fluid and operates the working apparatus.
Meanwhile, the actuators include a left traveling motor and a right traveling motor which are used to allow the construction equipment to travel, a boom cylinder, an arm cylinder, a bucket cylinder, and an option cylinder which are used to perform front work, and a swing motor which is used to turn an upper body.
On the other hand, in the case of the construction equipment, a traveling mode and a working mode may be selected. Straight traveling performance is improved when the traveling mode is selected, and working performance is preferentially improved rather than the traveling performance when the working mode is selected.
Further, the traveling mode and the working mode may be switched by operating the control valve.
However, in the case of the hydraulic circuit apparatus in the related art, there is a problem in that a flow path of the working fluid may be suddenly changed when the control valve is operated, and thus an impact occurs as a traveling speed is suddenly decreased. That is, an impact occurs when an operation of a front working apparatus is required while the construction equipment travels straight.
In addition, the hydraulic circuit apparatus in the related art has a problem in that the front work is slowly performed immediately after the control valve is operated. In detail, there is a problem in that when an operator operates the joystick in order to perform desired work while the construction equipment travels straight, a period of time from a point in time at which the joystick is operated to a point in time at which the corresponding actuator substantially begins to operate is increased. That is, there is a problem in that an operation of the front working apparatus is delayed when the operation of the front working apparatus is required while the construction equipment travels straight.

Literature of Related Art

(Patent Literature 1) Korean Patent Application Laid-Open No. 10-2003-0008069 (January 24, 2003 )
(Patent Literature 2) Korean Patent Application Laid-Open No. 10-2005-0066041 (June 30, 2005 )

[Disclosure]

[Technical Problem]

Therefore, a technical problem to be solved by the present disclosure is to provide an apparatus for controlling a hydraulic circuit of construction equipment which is capable of preventing an impact that occurs when an operation of a front working apparatus is required while the construction equipment travels straight.
Another technical problem to be solved by the present disclosure is to provide an apparatus for controlling a hydraulic circuit of construction equipment which is capable of reducing a period of time for which an operation of a front working apparatus is delayed when the operation of the front working apparatus is required while the construction equipment travels straight.

[Technical Solution]

To solve the aforementioned technical problems, an apparatus for controlling a hydraulic circuit of construction equipment according to an exemplary embodiment of the present disclosure includes: first and second pumps 11 and 12; a first traveling motor 41 which is supplied with a working fluid discharged from the first pump 11; a second traveling motor 42 which is supplied with the working fluid discharged from the second pump 12; a front working apparatus 50 which is supplied with the working fluid discharged from the first pump 11 or the second pump 12; a control valve 20 which is installed in a flow path between the first and second pumps 11 and 12 and the front working apparatus 50; a joystick 110 which produces a first operating signal for operating the front working apparatus 50; a traveling pedal 120 which produces a second operating signal for operating the first traveling motor 41 and the second traveling motor 42; and a control unit 400 which calculates, based on a control map, a control value for controlling the control valve 20, and outputs the control value to the control valve 20 when both of the first operating signal and the second operating signal are inputted.
In addition, according to the apparatus for controlling a hydraulic circuit of construction equipment according to the exemplary embodiment of the present disclosure, when the control valve 20 is controlled, the working fluid discharged from the second pump 12 may be supplied to the first traveling motor 41.
In addition, according to the apparatus for controlling a hydraulic circuit of construction equipment according to the exemplary embodiment of the present disclosure, the control valve 20 may merge the working fluid discharged from the first pump 11 and the working fluid discharged from the second pump 12.
In addition, according to the apparatus for controlling a hydraulic circuit of construction equipment according to the exemplary embodiment of the present disclosure, the front working apparatus 50 may include a boom cylinder, an arm cylinder, and a bucket cylinder.
In addition, according to the apparatus for controlling a hydraulic circuit of construction equipment according to the exemplary embodiment of the present disclosure, a control value of the control map may be changed at a predetermined gradient from a point in time t0 at which an operation of the front working apparatus 50 is required to a point in time t2 at which a displacement of a spool is maximized.
In addition, according to the apparatus for controlling a hydraulic circuit of construction equipment according to the exemplary embodiment of the present disclosure, the control value may be calculated such that a displacement of a spool of the control valve 20 is 40% to 80% of a maximum displacement at a point in time t0 at which an operation of the front working apparatus 50 is required.
In addition, according to the apparatus for controlling a hydraulic circuit of construction equipment according to the exemplary embodiment of the present disclosure, the control value may be calculated such that a displacement of a spool of the control valve 20 is 40% to 65% of a maximum displacement at a point in time t0 at which an operation of the front working apparatus 50 is required.
In addition, according to the apparatus for controlling a hydraulic circuit of construction equipment according to the exemplary embodiment of the present disclosure, the control value may be calculated such that a displacement of a spool of the control valve 20 is 55% to 75% of a maximum displacement at a point in time t0 at which an operation of the front working apparatus 50 is required.
In addition, according to the apparatus for controlling a hydraulic circuit of construction equipment according to the exemplary embodiment of the present disclosure, the control value may be increased from the point in time t0 at which the operation of the front working apparatus 50 is required to a point in time t2 at which a displacement of the spool is maximized.
In addition, according to the apparatus for controlling a hydraulic circuit of construction equipment according to the exemplary embodiment of the present disclosure, the control value may be changed at a predetermined gradient a from the point in time t0 at which the operation of the front working apparatus 50 is required to a point in time t2 at which a displacement of the spool is maximized.
Other detailed matters of the exemplary embodiment are included in the detailed description and the drawings.

[Advantageous Effects]

According to the apparatus for controlling a hydraulic circuit of construction equipment according to the exemplary embodiment of the present disclosure, which is configured as described above, a working fluid from the first pump may be provided early to the front working apparatus when traveling and working are required at the same time, and as a result, it is possible to advance the point in time at which the front working apparatus actually begins to operate.
In addition, according to the apparatus for controlling a hydraulic circuit of construction equipment according to the exemplary embodiment of the present disclosure, it is possible to mitigate an impact caused by a reduction in traveling speed by controlling the spool of the control valve so that a displacement of the spool of the control valve is changed at a predetermined gradient.

[Description of Drawings]

FIGS. 1 and 2 are views for explaining a hydraulic circuit of construction equipment according to an exemplary embodiment of the present disclosure.
FIG. 3 is a view for explaining a change in flow rate caused when a control valve is switched in the apparatus for controlling a hydraulic circuit of construction equipment according to the exemplary embodiment of the present disclosure.
FIG. 4 is a view for explaining a method of controlling a hydraulic circuit of construction equipment according to the exemplary embodiment of the present disclosure.
FIG. 5 is a view for explaining a control map for controlling the control valve in the apparatus for controlling a hydraulic circuit of construction equipment according to the exemplary embodiment of the present disclosure.
FIG. 6 is a view for explaining an operational effect of the apparatus for controlling a hydraulic circuit of construction equipment according to the exemplary embodiment of the present disclosure.

[Description of Main Reference Numerals of Drawings]

11, 12:: First and second pumps
20:: Control valve
31, 32:: First and second control valves
41:: First traveling motor
42:: Second traveling motor
50:: Front working apparatus
51, 52:: First and second actuator groups
100:: Input unit
110:: Joystick
120:: Traveling pedal
200:: Processing unit
210:: Determination unit
220:: Control map
300:: Output unit
400:: Control unit

[Best Mode]

Advantages and features of the present disclosure and methods of achieving the advantages and features will be clear with reference to exemplary embodiments described in detail below together with the accompanying drawings.
Hereinafter, exemplary embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. The exemplary embodiments to be described below are illustrative for helping understand the present disclosure, and it should be understood that the present disclosure may be implemented in various different ways from the exemplary embodiments described herein. However, in the description of the present disclosure, the specific descriptions and illustrations of publicly known functions or constituent elements will be omitted when it is determined that the specific descriptions may unnecessarily obscure the subject matter of the present disclosure. In addition, to help understand the present disclosure, the accompanying drawings are not illustrated based on actual scales, but parts of the constituent elements may be exaggerated in size.
Meanwhile, the terms used in the description are defined considering the functions of the present disclosure and may vary depending on the intention or usual practice of a manufacturer. Therefore, the definitions should be made based on the entire contents of the present specification.
Like reference numerals indicate like constituent elements throughout the specification.
Hereinafter, an apparatus for controlling a hydraulic circuit of construction equipment according to the exemplary embodiment of the present disclosure will be described with reference to FIGS. 1 and 2. The attached FIGS. 1 and 2 are views for explaining a hydraulic circuit of construction equipment according to the exemplary embodiment of the present disclosure.
As illustrated in FIGS. 1 and 2, the apparatus for controlling a hydraulic circuit of construction equipment according to the exemplary embodiment of the present disclosure may include first and second pumps 11 and 12, a control valve 20, a main control valve, and various types of actuators.
The first and second pumps 11 and 12 pressurize a working fluid and discharge the working fluid.
The control valve 20 is disposed between the first and second pumps 11 and 12 and the main control valve, and determines a flow direction of the working fluid discharged from the first and second pumps 11 and 12.
The various types of actuators may include a first traveling motor 41, a second traveling motor 42, and a front working apparatus 50.
The front working apparatus 50 may include boom cylinders, arm cylinders, and a bucket cylinder. In more detail, the front working apparatus 50 may be divided into a first actuator group 51 and a second actuator group 52.
The first actuator group 51 may include a second arm cylinder, a first boom cylinder, and the bucket cylinder. Meanwhile, the first actuator group 51 may further include an option apparatus.
The second actuator group 52 may include a first arm cylinder, a second boom cylinder, and a swing motor. Meanwhile, the second actuator group 52 may also further include another option apparatus.
The control valve 20 may be a two-position and four-port valve.
When a spool of the control valve 20 is positioned at a first position, the working fluid discharged from the first pump 11 is provided to the first traveling motor 41 and the first actuator group 51 as illustrated in FIG. 1. Further, the working fluid discharged from the second pump 12 is provided to the second traveling motor 42 and the second actuator group 52.
When the spool of the control valve 20 is positioned at a second position, the working fluid discharged from the first pump 11 is provided to the first actuator group 51 and the second actuator group 52 as illustrated in FIG. 2. Further, the working fluid discharged from the second pump 12 is provided to the first traveling motor 41 and the second traveling motor 42.
That is, when the spool of the control valve 20 is switched to the second position, the first pump 11 is responsible for the front working apparatus 50, and the second pump 12 is responsible for the first traveling motor 41 and the second traveling motor 42. As a result, straight traveling performance is improved when the construction equipment travels.
Hereinafter, a change in flow path area in accordance with a displacement of the spool of the control valve 20 will be described with reference to FIG. 3. The attached FIG. 3 is a view for explaining a change in flow rate caused when the control valve is switched in the apparatus for controlling a hydraulic circuit of construction equipment according to the exemplary embodiment of the present disclosure.
A position of the spool of the control valve 20 is determined in accordance with a magnitude of an electric current value. Further, as the spool of the control valve 20 is moved, a flow direction of the working fluid and a flow rate of the working fluid are changed. That is, the flow path area is changed as the spool is displaced, the flow rate is increased as the flow path area is increased, and the flow rate is decreased as the flow path area is decreased.
Because the control valve 20 is provided with four ports, four flow paths may be formed. A first port A is connected to the first pump 11. A second port B is connected to a first control valve 31 for controlling the first traveling motor 41. A third port C is connected to the second actuator group 52. A fourth port D is connected to the second pump 12.
A first flow path is a flow path which connects the first port A and the second port B. A second flow path is a flow path which connects the fourth port D and the third port C. That is, the first and second flow paths may be understood as flow paths when the control valve 20 is in an OFF state.
A third flow path is a flow path which connects the first port A and the third port C. A fourth flow path is a flow path which connects the fourth port D and the second port B. That is, the third and fourth flow paths may be understood as flow paths when the control valve 20 is in an ON state.
FIG. 3 is a diagram of flow path areas of the first, third, and fourth flow paths, and it is possible to understand how a flow rate of each of the flow paths is changed as a displacement of the spool of the control valve 20 is changed.
Meanwhile, as illustrated in FIG. 4, the apparatus for controlling a hydraulic circuit of construction equipment according to the exemplary embodiment of the present disclosure may include an input unit 100 and a control unit 400. Further, the control unit 400 may include a processing unit 200 and an operating unit 300.
The attached FIG. 4 is a view for explaining a method of controlling a hydraulic circuit of construction equipment according to the exemplary embodiment of the present disclosure.
A joystick 110 produces a first operating signal for operating the front working apparatus 50.
A traveling pedal 120 produces a second operating signal for operating the first and second traveling motors 41 and 42.
The input unit 100 receives the first operating signal for operating the front working apparatus 50, and the second operating signal for traveling. That is, any one of the first operating signal and the second operating signal may be inputted to the input unit 100, one signal may be inputted to the input unit 100 and then the other signal may be inputted to the input unit 100, or both of the first and second operating signals may be inputted to the input unit 100.
When both of the first operating signal and the second operating signal are inputted, the control unit 400 calculates, based on a control map, a control value for controlling the control valve 20, and outputs the control value to the control valve 20. The control unit 400 will be described in more detail below.
When both of the first operating signal and the second operating signal are inputted, a determination unit 210 of the processing unit 200 determines that an operation of the front working apparatus is required while the construction equipment travels. Further, based on a control map 220, the processing unit 200 calculates the control value for controlling the control valve 20.
Here, the control value may be understood as a value of electric current to be applied to the control valve 20. That is, when the value of electric current becomes a maximum value, a displacement of the spool of the control valve 20 may be maximized.
The output unit 300 outputs the control value, which is calculated by the processing unit 200, to the control valve 20, and as a result, the control valve 20 may be controlled by the control value.
That is, according to the apparatus for controlling a hydraulic circuit of construction equipment according to the exemplary embodiment of the present disclosure, a displacement of the spool of the control valve 20 is controlled in accordance with the control map, such that an area of the third flow path is increased at a point in time at which an operation of the front working apparatus 50 is required, and as a result, a part of the working fluid from the second pump 12 may be provided to the front working apparatus 50. As a result, it is possible to advance a point in time at which the front working apparatus 50 actually begins to operate.
In addition, according to the apparatus for controlling a hydraulic circuit of construction equipment according to the exemplary embodiment of the present disclosure, a displacement of the spool of the control valve 20 is controlled in accordance with the control map, such that an area of the first flow path may be reduced at a gradual rate in proportion to an increase in area of the third flow path. As a result, it is possible to prevent an impact by preventing a traveling speed from being suddenly reduced.
Meanwhile, when the control valve 20 is controlled, the working fluid discharged from the second pump 12 may be supplied to the first traveling motor 41. As a result, the second pump 12 may supply the working fluid not only to the second traveling motor 42 but also to the first traveling motor 41, and particularly, the second pump 12 may supply the working fluid to the first and second traveling motors 41 and 42 simultaneously, such that it is possible to improve straight traveling performance.
On the other hand, according to the apparatus for controlling a hydraulic circuit of construction equipment according to the exemplary embodiment of the present disclosure, the control value may be calculated such that a displacement of the spool of the control valve 20 becomes 40% to 80% of a maximum displacement at a point in time t0 at which an operation of the front working apparatus 50 is required.
As described above, in a case in which a displacement of the spool of the control valve 20 is 40% or more of the maximum displacement, a part of the working fluid discharged from the second pump 12 is provided, at an appropriate flow rate, to the front working apparatus 50 through the third flow path, and as a result, the front working apparatus may be smoothly operated.
In addition, in a case in which the displacement of the spool of the control valve 20 is 80% or less of the maximum displacement, the working fluid is continuously provided to the first traveling motor 41 through the first flow path, and as a result, it is possible to prevent a traveling speed of the construction equipment from being rapidly reduced.
On the other hand, according to the apparatus for controlling a hydraulic circuit of construction equipment according to the exemplary embodiment of the present disclosure, the control value may be calculated such that a displacement of the spool of the control valve 20 becomes 40% to 65% of the maximum displacement at a point in time t0 at which an operation of the front working apparatus 50 is required. As a result, it is possible to operate the front working apparatus 50 within an optimized range in which an operating speed of the front working apparatus 50 is not decreased.
On the other hand, according to the apparatus for controlling a hydraulic circuit of construction equipment according to the exemplary embodiment of the present disclosure, the control value may be calculated such that a displacement of the spool of the control valve 20 becomes 55% to 75% of the maximum displacement at a point in time t0 at which an operation of the front working apparatus 50 is required. Here, in a case in which the displacement of the spool of the control valve 20 is 55% or more of the maximum displacement, tuning may be performed so that a speed of a working machine is improved. Meanwhile, in a case in which the displacement of the spool of the control valve 20 is 75% or more of the maximum displacement, tuning may be performed so that a traveling speed is softly decreased.
The control map will be described with reference to FIG. 5. The attached FIG. 5 is a view for explaining the control map for controlling the control valve in the apparatus for controlling a hydraulic circuit of construction equipment according to the exemplary embodiment of the present disclosure.
In the apparatus for controlling a hydraulic circuit of construction equipment according to the exemplary embodiment of the present disclosure, the control value may be constantly changed at a predetermined gradient a from the point in time t0 at which the operation of the front working apparatus 50 is required to a point in time t2 at which the displacement of the spool is maximized. As a result, it is possible to prevent a displacement of the spool of the control valve 20 from being rapidly changed to a maximum value, and it is possible to control a traveling speed of the construction equipment so that the traveling speed is gradually decreased.
The construction equipment may be shipped in a state in which the predetermined gradient a may be set by a manufacturer, or the predetermined gradient may be newly set as necessary.
Hereinafter, the method of controlling a hydraulic circuit of construction equipment according to the exemplary embodiment of the present disclosure will be described for each step.
Input Step: a step of receiving the first operating signal for operating the front working apparatus 50 or the second operating signal for traveling. That is, in a case in which only the second operating signal is inputted, it may be determined that only the traveling is performed, but in a case in which the first operating signal is inputted in a situation in which the second operating signal is inputted, it may be determined that the front working apparatus is intended to be operated while the construction equipment travels.
Further, the joystick 110 is operated to operate the desired actuator, and in this case, pilot pressure is produced. Therefore, whether the first operating signal is inputted may be determined based on whether the pilot pressure is produced in a pilot line. In addition, when the traveling pedal 120 is pressed for the purpose of traveling, the second operating signal is produced. The second operating signal may be recognized based on the ON/OFF state of the control valve 20.
Calculation Step: a step of determining whether the situation is a situation in which both of the first operating signal and the second operating signal are inputted, and calculating the control value of the control valve 20 based on the control map when it is determined that the situation is a situation in which the first and second operating signals are simultaneously inputted. That is, when it is determined that the front working apparatus is operated while the construction equipment travels, the spool of the control valve 20 is controlled, such that areas of the first, second, third, and fourth flow paths are changed. As a result, a flow rate provided to the front working apparatus 50 may be increased at a particular point in time. Here, the particular point in time is the point in time t0 at which the operation of the front working apparatus is required while the construction equipment travels.
Operating Step: a step of controlling the control valve 20 in accordance with the control value calculated in the calculation step. As a result, the control valve 20 may implement a particular displacement at every particular point.
Therefore, according to the method of controlling a hydraulic circuit of construction equipment according to the exemplary embodiment of the present disclosure, a displacement of the spool of the control valve 20 is controlled in accordance with the control map, such that a part of the working fluid from the second pump 12 may be provided to the front working apparatus 50 at the point in time t0 at which the operation of the front working apparatus 50 is required. As a result, it is possible to advance a point in time t1 at which the front working apparatus 50 actually begins to operate.
In addition, according to the method of controlling a hydraulic circuit of construction equipment according to the exemplary embodiment of the present disclosure, a displacement of the spool of the control valve 20 is controlled in accordance with the control map, such that an area of the first flow path may be reduced at a gradual rate in proportion to an increase in area of the third flow path. As a result, it is possible to prevent an impact by preventing a traveling speed from being suddenly reduced.
Meanwhile, according to the method of controlling a hydraulic circuit of construction equipment according to the exemplary embodiment of the present disclosure, the control value may be set such that a displacement of the spool of the control valve 20 becomes 50% to 70% of the maximum displacement at the point in time t0 at which the operation of the front working apparatus 50 is required.
As a result, since a part of the working fluid discharged from the second pump 12 is provided, at an appropriate flow rate, to the front working apparatus 50 through the third flow path, the front working apparatus may be smoothly operated, and since the working fluid is continuously provided to the first traveling motor 41 through the first flow path, it is possible to prevent a traveling speed of the construction equipment from being rapidly reduced.
On the other hand, according to the method of controlling a hydraulic circuit of construction equipment according to the exemplary embodiment of the present disclosure, the control value may be changed at a predetermined gradient a from the point in time t0 at which the operation of the front working apparatus 50 is required to the point in time t2 at which the displacement of the spool is maximized.
As a result, it is possible to prevent a displacement of the spool of the control valve 20 from being rapidly changed to the maximum displacement, and it is possible to control a traveling speed of the construction equipment so that the traveling speed is gradually decreased.
Hereinafter, an operational effect of the apparatus for controlling a hydraulic circuit of construction equipment according to the exemplary embodiment of the present disclosure will be described with reference to FIG. 6. The attached FIG. 6 is a view for explaining an operational effect of the apparatus for controlling a hydraulic circuit of construction equipment according to the exemplary embodiment of the present disclosure.
According to Example 1, a displacement of the spool is gradually increased from the point in time t0 at which the operation of the front working apparatus 50 is required to the point in time t2 at which the displacement of the spool is maximized. The working fluid discharged from the first pump 11 is distributed to the first traveling motor 41 at a maximum flow rate, and the working fluid is rarely distributed to the front working apparatus 50. The working fluid discharged from the second pump 12 is distributed to the second traveling motor 42 at a maximum flow rate, and the working fluid is rarely distributed to the first traveling motor 41.
Thereafter, the spool of the control valve 20 is moved, such that a displacement of the spool is increased to the extent the front working apparatus 50 may begin to operate. That is, the point in time t1 at which the front working apparatus 50 begins to operate is after a predetermined period of time is delayed from the point in time t0 at which the operation of the front working apparatus 50 is required.
Meanwhile, according to Example 1, at the point in time t1 at which the front working apparatus 50 begins to operate, a flow rate of the working fluid, which is discharged from the first pump 11 and distributed to the first traveling motor 41, is decreased, and a flow rate of the working fluid, which is distributed to the front working apparatus 50, is increased as much as the decreased flow rate. In addition, a flow rate of the working fluid, which is discharged from the second pump 12 and distributed to the second traveling motor 42, is decreased, and a flow rate of the working fluid, which is distributed to the first traveling motor 41, is increased as much as the decreased flow rate.
Therefore, according to Example 1, the flow rate is rapidly changed even though the period of time from the point in time t1 at which of the front working apparatus 50 begins to operate to the point in time t2 at which the displacement of the spool is maximized is short, and as a result, an impact may occur when the front working apparatus 50 is operated while the construction equipment travels.
In contrast, according to Example 2 of the present disclosure, a displacement of the spool begins from an initiation displacement at the point in time t0 at which the operation of the front working apparatus 50 is required. The initiation displacement may be a displacement by which a position of the spool is already moved so much in comparison with the initial displacement according to Example 1. Further, a displacement of the spool is gradually increased from the initiation displacement until the displacement of the spool is maximized.
From the point in time t0 at which the operation of the front working apparatus 50 is required, a flow rate of the working fluid, which is discharged from the first pump 11 and distributed to the first traveling motor 41, is gradually decreased, and a flow rate of the working fluid, which is distributed to the front working apparatus 50, is increased as much as the decreased flow rate. A flow rate of the working fluid, which is discharged from the second pump 12 and distributed to the second traveling motor 42, is gradually decreased, and a flow rate of the working fluid, which is distributed to the first traveling motor 41, is increased as much as the decreased flow rate.
That is, according to the apparatus for controlling a hydraulic circuit of construction equipment according to Example 2 of the present disclosure, when the operation of the front working apparatus 50 is required while the construction equipment travels, the working fluid discharged from the first pump 11 may be provided to the front working apparatus 50, and as a result, it is possible to advance the point in time t1 at which the front working apparatus 50 actually begins to operate. Therefore, the point in time t1 at which the front working apparatus 50 begins to operate may be a point in time identical to or very close to the point in time t0 at which the operation of the front working apparatus 50 is required.
Meanwhile, according to the apparatus for controlling a hydraulic circuit of construction equipment according to Example 2 of the present disclosure, a period of time from the point in time t1 at which the front working apparatus 50 begins to operate to the point in time t2 at which the displacement of the spool is maximized is relatively longer than that in Example 1. Therefore, because a flow rate is changed for the relatively long period of time, a change in flow rate may be gradual, and as a result, it is possible to prevent a traveling speed from being rapidly reduced.
As described above, according to the apparatus for controlling a hydraulic circuit of construction equipment according to Example 2 of the present disclosure, the displacement of the spool of the control valve 20 is set to be 40% to 80% of the maximum displacement when traveling and working are required at the same time, and as a result, it is possible to advance the point in time at which the front working apparatus actually begins to operate.
In addition, according to the apparatus for controlling a hydraulic circuit of construction equipment according to Example 2 of the present disclosure, it is possible to mitigate an impact caused by a reduction in traveling speed by controlling the control valve 20 so that a displacement of the spool of the control valve 20 is changed at a predetermined gradient a.
While the exemplary embodiments of the present disclosure have been described with reference to the accompanying drawings, those skilled in the art will understand that the present disclosure may be implemented in any other specific form without changing the technical spirit or an essential feature thereof.
Accordingly, it should be understood that the aforementioned exemplary embodiment is described for illustration in all aspects and is not limited, and the scope of the present disclosure shall be represented by the claims to be described below, and it should be construed that all of the changes or modified forms induced from the meaning and the scope of the claims, and an equivalent concept thereto are included in the scope of the present disclosure.

[Industrial Applicability]

The apparatus for controlling a hydraulic circuit of construction equipment according to the exemplary embodiment of the present disclosure may be used to prevent a delay of a point in time at which the front working apparatus begins to operate when the front working apparatus is operated to be moved while the construction equipment travels.

Claims

An apparatus for controlling a hydraulic circuit of construction equipment, the apparatus comprising:
a first pump 11 and a second pump 12;

a first traveling motor 41 which is supplied with a working fluid discharged from the first pump 11;

a second traveling motor 42 which is supplied with the working fluid discharged from the second pump 12;

a front working apparatus 50 which is supplied with the working fluid discharged from the first pump 11 or the second pump 12;

a control valve 20 which is installed in a flow path between the first and second pumps 11 and 12 and the front working apparatus 50;

a joystick 110 which produces a first operating signal for operating the front working apparatus 50;

a traveling pedal 120 which produces a second operating signal for operating the first traveling motor 41 and the second traveling motor 42; and

a control unit 400 which calculates, based on a control map, a control value for controlling the control valve 20, and outputs the control value to the control valve 20 when both of the first operating signal and the second operating signal are inputted.
The apparatus of claim 1, wherein when the control valve 20 is controlled, the working fluid discharged from the second pump 12 is supplied to the first traveling motor 41.
The apparatus of claim 1, wherein the control valve 20 merges the working fluid discharged from the first pump 11 and the working fluid discharged from the second pump 12.
The apparatus of claim 1, wherein the front working apparatus 50 includes a boom cylinder, an arm cylinder, and a bucket cylinder.
The apparatus of claim 1, wherein a control value of the control map is changed at a predetermined gradient from a point in time t0 at which an operation of the front working apparatus 50 is required to a point in time t2 at which a displacement of a spool is maximized.
The apparatus of claim 1, wherein the control value is calculated such that a displacement of a spool of the control valve 20 is 40% to 80% of a maximum displacement at a point in time t0 at which an operation of the front working apparatus 50 is required.
The apparatus of claim 1, wherein the control value is calculated such that a displacement of a spool of the control valve 20 is 40% to 65% of a maximum displacement at a point in time t0 at which an operation of the front working apparatus 50 is required.
The apparatus of claim 1, wherein the control value is calculated such that a displacement of a spool of the control valve 20 is 55% to 75% of a maximum displacement at a point in time t0 at which an operation of the front working apparatus 50 is required.
The apparatus of claim 1 or 6, wherein the control value is increased from the point in time t0 at which the operation of the front working apparatus 50 is required to a point in time t2 at which a displacement of the spool is maximized.
The apparatus of claim 6, wherein the control value is changed at a predetermined gradient a from the point in time t0 at which the operation of the front working apparatus 50 is required to a point in time t2 at which a displacement of the spool is maximized.