Apparatus and method for controlling spool displacement of construction machine

Abstract

Provided are an apparatus and a method for controlling spool displacement of a construction machine, which are capable of improving regeneration efficiency of the construction machine, and improving a fuel efficiency characteristic of the construction machine by reducing pressure loss in the operating mode by adjusting the quantity of spool displacement in a regeneration mode when a current pressure of a main pump is less than a predetermined operating pressure, and determining whether the construction machine is in an operating mode or the regeneration mode in real time according to an operating angle of a joystick and the current pressure of the main pump when the current pressure of the main pump is greater than or equal to the predetermined operating pressure to variably change the quantity of spool displacement in the operating mode.

Claims

1. An apparatus for controlling displacement of a spool of a construction machine, which comprises a main pump driven by an engine, actuator driven by working oil discharged from the main pump, a main control valve configured to control driving of the actuator according to a quantity of displacement of a spool installed therein, a joystick configured to adjust the main control valve, and a pilot gear pump configured to discharge working oil for driving the main control valve, the apparatus comprising: a control unit configured to generate a signal for the quantity of displacement of the spool according to a quantity of operation of the joystick and a current pressure of the main pump; a spool displacement adjusting unit configured to adjust the quantity of displacement of the spool according to the signal generated by the control unit; and a hydraulic line configured to supply working oil discharged from the pilot gear pump to the spool displacement adjusting unit, wherein the control unit includes: a joystick operation quantity determining unit configured to determine the quantity of operation of the joystick; a main pump pressure comparing unit configured to compare the current pressure of the main pump with a predetermined operating pressure; and a signal generating unit configured to generate a signal for controlling the spool to have a value of displacement quantity smaller than a maximum permissible displacement quantity of the spool as recognized to be in a regeneration mode when the current pressure of the main pump is less than the predetermined operating pressure as a result of the determination of the main pump pressure comparing unit, and generate a signal for controlling the spool to have a value of the maximum permissible displacement quantity of the spool as determined to be in an operating mode when the pressure of the main pump is greater than or equal to the predetermined operating pressure, wherein the predetermined operating pressure is formed in a predetermined numerical range having a lower limit value and an upper limit value, wherein the spool displacement is adjusted in the regeneration mode when the current pressure of the main pump is less than the lower limit value, wherein the spool displacement is adjusted in the operating mode when the current pressure of the main pump is greater than or equal to the upper limit value, and wherein when the current pressure of the main pump is greater than or equal to the lower limit value and less than the upper limit, the spool displacement is adjusted to increase linearly from the spool displacement adjusted in the regeneration mode to the spool displacement adjusted in the operating mode.

2. The apparatus of claim 1, wherein the signal for changing the spool to have a value smaller than the maximum permissible displacement quantity of the spool generated by the signal generating unit has a value of 70% to 90% of the maximum permissible displacement quantity of the spool.

3. The apparatus of claim 2, wherein the spool displacement adjusting unit is an electronic proportional pressure reducing valve (EPPRV).

4. The apparatus of claim 1, wherein the spool displacement adjusting unit is an electronic proportional pressure reducing valve (EPPRV).

5. A method of controlling spool displacement of a construction machine, the method comprising: determining a quantity of operation of a joystick by a driver; comparing a current pressure of a main pump with a predetermined operating pressure; generating a signal for determining a quantity of displacement of a spool according to the quantity of the operation of the joystick according to a result of the comparison; adjusting the quantity of displacement of the spool according to the generated signal, wherein, after the comparing the current pressure of the main pump with the predetermined operating pressure, the method is further comprising: generating a signal for changing the spool to have a value smaller than a maximum permissible displacement quantity of the spool as recognized to be in a regeneration mode when the pressure of the main pump is less than the predetermined operating pressure; and generating a signal for changing the spool to have a value of the maximum permissible displacement quantity of the spool as determined to be in an operating mode when the pressure of the main pump is greater than or equal to the predetermined operating pressure, wherein the predetermined operating pressure is formed in a predetermined numerical range having a lower limit value and an upper limit value, wherein the spool displacement is adjusted in the regeneration mode when the current pressure of the main pump is less than the lower limit value, wherein the spool displacement is adjusted in the operating mode when the current pressure of the main pump is greater than or equal to the upper limit value, and wherein when the current pressure of the main pump is greater than or equal to the lower limit value and less than the upper limit, the spool displacement is adjusted to increase linearly from the spool displacement adjusted in the regeneration mode to the spool displacement adjusted in the operating mode.

6. The method of claim 5, wherein the signal generated in the generating the signal for changing the spool to have the value smaller than the maximum permissible displacement quantity of the spool has a value of 70% to 90% of the maximum permissible displacement quantity of the spool.

Description

DESCRIPTION OF DRAWINGS

(1) FIG. 1 is a schematic diagram for describing efficiency of a construction machine in an operating mode and a regeneration mode in the construction machine in the related art.

(2) FIG. 2 is a graph for a design of an orifice area in consideration of efficiency of the operating mode and the regeneration mode in the construction machine in the related art.

(3) FIG. 3 is a block diagram illustrating an apparatus for controlling spool displacement of a construction machine according to an exemplary embodiment of the present disclosure.

(4) FIG. 4 is a graph illustrating the quantity of change according to the quantity of operation of a joystick and spool displacement.

(5) FIG. 5 is a graph illustrating the quantity of spool displacement and a state, in which an orifice area is changed into an optimized state according to the quantity of spool displacement according to the apparatus for controlling spool displacement of the construction machine according to the exemplary embodiment of the present disclosure.

(6) FIG. 6 is a graph illustrating the quantity of operation of a joystick and the quantity of spool displacement when a pressure in an operating mode is between 100 bar to 150 bar according to the exemplary embodiment of the present disclosure.

(7) FIG. 7 is a flowchart of a method for controlling spool displacement of a construction machine according to an exemplary embodiment of the present disclosure.

(8) TABLE-US-00001 <Description of Reference Numerals and Signs> 2: Main pump 3: Main control valve 4: Joystick 5: Pilot gear pump 6: Orifice 7: Cylinder 8: Spool 10: Control unit 11: Joystick operation quantity determining unit 12: Main pump pressure comparing unit 13: Signal generating unit 20: Spool displacement adjusting unit 30: Hydraulic line S1: Operation of determining quantity of operation of joystick S2: Operation of comparing current pressure of main pump with predetermined operating pressure S2-1: Operation of generating signal for changing spool to have value less than maximum permissible displacement quantity of spool S2-2: Operation of generating signal for changing spool to have maximum permissible displacement quantity of spool S3: Operation of generating signal S4: Operation of adjusting quantity of displacement of spool

(9) Hereinafter, an exemplary embodiment of the present disclosure will be described in detail with reference to the accompanying drawings. First of all, in giving reference numerals to elements of each drawing, like reference numerals refer to like elements.

(10) FIG. 3 is a block diagram illustrating an apparatus for controlling spool displacement of a construction machine according to an exemplary embodiment of the present disclosure. FIG. 4 is a graph illustrating the quantity of change according to an operating angle of a joystick and spool displacement, FIG. 5 is a graph illustrating the quantity of spool displacement and a state, in which an orifice area is changed into an optimized state according to the quantity of spool displacement, according to the apparatus for controlling spool displacement of the construction machine according to the exemplary embodiment of the present disclosure, and FIG. 6 is a graph illustrating the quantity of operation of a joystick and the quantity of spool displacement when a pressure in an operating mode is between 100 bar to 150 bar according to the exemplary embodiment of the present disclosure.

(11) An apparatus 100 for controlling spool displacement of a construction machine according to the present disclosure will be described with reference to FIGS. 3 to 6. The apparatus 100 for controlling spool displacement of the construction machine according to the present disclosure includes a control unit 10, a spool displacement adjusting unit 20, and a hydraulic line 30.

(12) The main pump 2 is driven by an engine, and actuators, such as a boom, an arm, a bucket, a swing, a travel device, are driven by working oil discharged from the main pump 2.

(13) A main control valve (MCV) 3 controls the driving of the actuator according to displacement of a spool 8 installed therein.

(14) That is, displacement of the spool 8 installed in the MCV 3 is adjusted according to the quantity of operation of a joystick 4 by a driver. More particularly, a pilot gear pump 5 discharges working oil in order to drive the spool 8 installed inside the MCV 3 according to a signal of the joystick 4.

(15) The control unit 10 generates a signal for the quantity of displacement of the spool 8 according to the quantity of operation of the joystick 4 and a current pressure of the main pump 2.

(16) The spool displacement adjusting unit 20 adjusts the quantity of displacement of the spool 8 according to a signal generated by the control unit 10.

(17) The hydraulic line 30 is connected to the spool displacement adjusting unit 20, and supplies working oil discharged from the pilot gear pump 5 to the spool displacement adjusting unit 20.

(18) According to another exemplary embodiment of the present disclosure, the spool displacement adjusting unit 20 is formed with an electronic proportional pressure reducing valve (EPPRV).

(19) Accordingly, the spool displacement adjusting unit 20 formed with the EPPRV variably adjusts the quantity of displacement of the spool 8 by transmitting pressure of the working oil discharged from the pilot gear pump 5 with the same pressure to the spool with changed pressure in real time according to a signal generated, by the control unit, by determining and comparing the quantity of operation of the joystick 4 and the current pressure of the main pump 2.

(20) As illustrated in FIG. 3, a control unit 10 of an apparatus 100 for controlling spool displacement of a construction machine according to another exemplary embodiment of the present disclosure includes a joystick operation quantity determining unit 11, a main pump pressure comparing unit 12, and a signal generating unit 13.

(21) The joystick operation quantity determining unit 11 determines the quantity of operation of the joystick 4, that is, an operating angle of the joystick 4, operated by the driver.

(22) The main pump pressure comparing unit 12 compares a current pressure of the main pump 2 with a predetermined operating pressure.

(23) As illustrated in FIG. 6, according to the exemplary embodiment of the present disclosure, the predetermined operating pressure is formed in a predetermined numerical range having a lower limit value and an upper limit value. In one embodiment, the predetermined operating pressure can be set to a numerical range having an upper limit value of 150 bar from a lower limit value of 100 bar.

(24) In one embodiment, in a case where the predetermined operating pressure is a numerical range of 100 bar to 150 bar, when the current pressure of the main pump is equal to or greater than the upper limit value of 150 bar, the main pump pressure comparing unit 12 determines a mode of the apparatus 100 as an operating mode, and when the current pressure of the main pump is less than the lower limit value of 100 bar the main pump pressure comparing unit 12 recognizes a mode of the apparatus 100 as a regeneration mode.

(25) However, the predetermined operating pressure may be variously changed according to the kind and a size of the construction machine, and a setting mode of the construction machine.

(26) The signal generating unit 13 generates a signal for changing the spool to have a value smaller than a maximum permissible displacement quantity of the spool 8 when the current pressure of the main pump 2 is less than the predetermined operating pressure according to a result of the determination of the main pump pressure comparing unit 12. The present disclosure is not essentially limited thereto, and the signal for changing the spool 8 to have the value smaller than the maximum permissible displacement quantity of the spool 8 generated by the signal generating unit 13 is formed with a value of 70% to 90% of the maximum permissible displacement quantity of the spool 8. Further, when the current pressure of the main pump 2 is greater than or equal to the predetermined operating pressure, the signal generating unit 13 generates a signal formed with a value of the maximum permissible displacement quantity of the spool 8.

(27) That is, as illustrated in FIG. 4, when the current pressure of the main pump 2 is less than the predetermined operating pressure, the spool 8 is changed to have only 70% to 90% of the maximum permissible displacement quantity of the spool 8, and when the current pressure of the main pump 2 is greater than or equal to the predetermined operating pressure, the spool 8 is changed to have the maximum permissible displacement quantity of the spool 8.

(28) When the maximum permissible displacement quantity of the spool 8 is less than 70%, the quantity of displacement of the spool 8 does not much influence regeneration efficiency, and when the maximum permissible displacement quantity of the spool 8 is equal to or greater than 90%, the problem generated in the construction machine in the related art may be incurred again in the regeneration mode, so that it is preferable to design the spool so that the spool is changed only to have a value of 70% to 90% of the maximum permissible displacement quantity of the spool 8 when the current pressure of the main pump 2 is less than the predetermined operating pressure.

(29) As illustrated in FIG. 5, the quantity of operation of the joystick, and the current pressure state and the predetermined operating pressure of the construction machine are compared in real time, and the quantity of displacement of the spool 8 is variably controlled according to a value of the comparison, so that unlike the graph of FIG. 2 in the related art, an area line diagram of the orifice is changed according to an optimum area line diagram of the orifice.

(30) Accordingly, regeneration efficiency of the construction machine may be increased, and operating efficiency may be improved by reducing pressure loss.

(31) Further, the quantity of spool displacement is automatically changed into an optimum state without requiring a separate operation performed by the driver according to an operating mode state of the construction machine changed in real time, and thus an orifice area is changed into an optimum state, thereby improving convenience.

(32) FIG. 7 is a flowchart of a method for controlling spool displacement of a construction machine according to an exemplary embodiment of the present disclosure.

(33) A method for controlling spool displacement of a construction machine according to an exemplary embodiment of the present disclosure will be described with reference to FIG. 7. The method for controlling spool displacement of the construction machine according to the present disclosure includes operation S1 of determining a joystick operation quantity, operation S2 of comparing a current pressure of the main pump with a predetermined operating pressure, operation S3 of generating a signal, and operation S4 of adjusting a spool displacement quantity.

(34) In operation S1 of determining a joystick operation quantity, the quantity of operation of the joystick 4, that is, an operating angle of the joystick 4, operated by a driver is determined. In operation S2 of comparing a current pressure of the main pump with a predetermined operating pressure, a current pressure of the main pump is compared with a predetermined operating pressure. As described above, the predetermined operating pressure may be variously changed and set according to the kind and a size of the construction machine, and a setting mode of the construction machine.

(35) A signal for determining the quantity of displacement of the spool 8 is generated according to a result of the determination of the quantity of operation of the joystick, and a result of the comparison between the current pressure of the main pump 8 and the predetermined operating pressure.

(36) The spool displacement adjusting unit 20, more particularly, the EPPRV, adjusts the quantity of displacement of the spool according to the signal generated after operation S3 of generating the signal.

(37) As illustrated in FIG. 7, according to another exemplary embodiment of the present disclosure, the method further includes operation S2-2 of generating a signal for changing the spool 8 to have a value smaller than a maximum permissible displacement quantity of the spool 8 when the pressure of the main pump 2 is less than the predetermined operating pressure, and operation S2-1 of generating a signal for changing the spool 8 to have a value of the maximum permissible displacement quantity of the spool 8 when the pressure of the main pump 2 is greater than or equal to the predetermined operating pressure, after operation S2 of comparing the current pressure of the main pump 2 with the predetermined operating pressure.

(38) In this case, the signal generated in operation S2-2 of generating the signal for changing the spool 8 to have the value smaller than the maximum permissible displacement quantity of the spool 8 is formed with a value of 70% to 90% of the maximum permissible displacement quantity of the spool 8.

(39) That is, it is possible to improve regeneration efficiency during the operation in the regeneration mode, and decreasing energy consumption by reducing pressure loss during the operation in the operating mode by determining the operating angle of the joystick of the driver and comparing the current pressure of the main pump 2 with the predetermined operating pressure, and controlling the quantity of displacement of the spool 8 according to the values of the determination and the comparison without requiring a separate operation performed by the driver.

(40) The present disclosure is not limited to a modified embodiment illustrated in the drawing and the aforementioned exemplary embodiments, and may be expanded to another exemplary embodiment belonging to a scope of the accompanying claims.

INDUSTRIAL APPLICABILITY

(41) The present disclosure relates to an apparatus and a method for controlling spool displacement of a construction machine, and more particularly, to an apparatus and a method for controlling spool displacement of a construction machine, which are capable of improving regeneration efficiency of the construction machine, and improving a fuel efficiency characteristic of the construction machine by reducing pressure loss in the operating mode by determining an operating angle of a joystick by a driver and comparing a current pressure of a main pump with a predetermined operating pressure, adjusting the quantity of spool displacement in a regeneration mode when the current pressure of the main pump is less than the predetermined operating pressure, and variably adjusting the quantity of spool displacement in an operating mode when the current pressure of the main pump is greater than or equal to the predetermined operating pressure.