Construction machine

Abstract

The present invention relates to a construction machine including: a pump connected to an engine; a pump line through which a fluid is discharged from the pump; a main control valve which enables the pump line to communicate with multiple actuators; a regeneration line which enables at least one of the multiple actuators to communicate with the pump line; and a control unit which determines a regeneration flow rate of the regeneration line according to a mode and controls the pump. Therefore, the performance and fuel efficiency thereof can be improved.

Description

construction machinery

[0001] The present invention relates to construction machinery, and more particularly, to construction machinery capable of performing civil engineering or construction work.

[0002] In general, construction machinery is a machine used in civil engineering or construction work, such as an excavator or loader, and includes a lower body that can move along the ground, an upper rotating body that is rotatably provided on top of the lower body, a boom that is rotatably connected to the upper rotating body, a hydraulic circuit for operating the upper rotating body and the boom, and a control unit that controls the hydraulic circuit.

[0003] However, conventional construction machines had problems with poor performance and fuel efficiency.

[0004] Accordingly, the present invention aims to provide a construction machine capable of improving performance and fuel efficiency.

[0005] The present invention provides a construction machine comprising: a pump connected to an engine; a pump line through which a flow rate is discharged from the pump; a main control valve connecting the pump line to a plurality of actuators; a regeneration line connecting at least one of the plurality of actuators to the pump line; and a control unit determining a regeneration flow rate of the regeneration line according to a mode and controlling the pump.

[0006] The above plurality of actuators include a swing actuator and a boom actuator, and a swing line connecting the main control valve and the swing actuator and a boom line connecting the main control valve and the boom actuator are provided, and the recovery line can connect at least one of the swing line and the boom fine with the pump line.

[0007] If the flow rate of the fluid supplied to the main control valve through the pump line is called the supply flow rate, the flow rate of the fluid supplied by the pump to the pump line is called the pump flow rate, and the flow rate of the fluid supplied to the pump line through the recovery line is called the recovery flow rate, the control unit can determine the pump flow rate from the difference between the supply flow rate and the recovery flow rate determined according to the mode and control to drive the pump.

[0008] The supply flow rate, which is the flow rate of the fluid supplied to the main control valve through the pump line, may be the sum of the basic supply flow rate determined according to the operator's input value and the additional supply flow rate, which is the flow rate exceeding the basic supply flow rate.

[0009] The above additional supply flow rate is determined by multiplying the maximum recovery flow rate, which is the maximum of the recovery flow rate, by a predetermined performance constant, and the performance constant can be determined in the range of 0 to 1 depending on the mode.

[0010] In normal mode, the above recovery line may be disabled.

[0011] When in recovery mode, the above recovery line may be activated.

[0012] In fuel economy mode, the regeneration flow rate of the regeneration line may increase, and the pump flow rate supplied by the pump to the pump line may be reduced based on the increased regeneration flow rate.

[0013] In performance mode, the regeneration flow rate of the regeneration line is increased, and the pump flow rate supplied by the pump to the pump line can be maintained.

[0014] In the case of a composite mode, the regenerative flow rate of the recovery line may be increased and the pump flow rate supplied to the pump line by the pump may be decreased according to a ratio determined in the composite mode.

[0015] The above-mentioned recovery flow rate is determined by multiplying the maximum recovery flow rate, which is the maximum value of the above-mentioned recovery flow rate, by a predetermined recovery constant, and the above-mentioned recovery constant can be determined in the range of 0 to 1 depending on the mode.

[0016] In normal mode, the above recovery constant can be determined as 0.

[0017] In the recovery mode, the recovery constant can be determined as the maximum value currently possible in the range of 0 to 1.

[0018] The above recovery line includes a high pressure accumulator for storing and discharging fluid and a confluence flow path connecting the high pressure accumulator with the pump line, and the control unit can open and close the confluence flow path so that a predetermined flow rate flows from the high pressure accumulator to the pump line under predetermined conditions.

[0019] The operator selects a target actuator from the plurality of actuators, and the control unit can open the joining flow path when the target actuator operates under predetermined conditions.

[0020] The confluence path may be opened when the pressure of the target actuator is greater than a predetermined reference pressure, the confluence path may be opened when the pressure of the target actuator is less than or equal to the predetermined reference pressure and the output of the pump is greater than the predetermined reference output, and the confluence path may be opened when the pressure of the high-pressure accumulator is greater than a predetermined value.

[0021] The above operator sets a predetermined ratio for each of the target actuator and the pump, and the control unit can control the confluence flow path so that the maximum value among the calculated flow rates obtained by multiplying the ratio by the maximum flow rate that can flow from the high pressure accumulator to the pump line flows from the high pressure accumulator to the pump line.

[0022] The pump may include a first pump and a second pump, the pump line may include a first pump line communicating with the first pump and a second pump line communicating with the second pump, the target actuator may include a first target actuator communicating with the first pump line and a second target actuator communicating with the second pump line, and the merging flow path may include a first merging line communicating with the first pump line and a second merging line communicating with the second pump line.

[0023] A first ratio for the first target actuator, a second ratio for the second target actuator, a third ratio for the first pump, and a fourth ratio for the second pump are set by the operator, and the control unit can calculate a first calculated flow rate obtained by multiplying the first ratio by the maximum flow rate that can flow from the high pressure accumulator to the first pump line for operation of the first target actuator, a second calculated flow rate obtained by multiplying the second ratio by the maximum flow rate that can flow from the high pressure accumulator to the second pump line for operation of the second target actuator, a third calculated flow rate obtained by multiplying the third ratio by the maximum flow rate that can flow from the high pressure accumulator to the first pump line for operation of the first pump, and a fourth calculated flow rate obtained by multiplying the fourth ratio by the maximum flow rate that can flow from the high pressure accumulator to the second pump line for operation of the second pump.

[0024] The control unit can control the first merging line and the second merging line so that the maximum value among the first output flow rate, the second output flow rate, the third output flow rate, and the fourth output flow rate flows from the high pressure accumulator to the pump line.

[0025] The control unit may control the first output flow rate to flow to the first merging line when the maximum value is the first output flow rate, control the second output flow rate to flow to the second merging line when the maximum value is the second output flow rate, control the third output flow rate to flow to the first merging line when the maximum value is the third output flow rate, and control the fourth output flow rate to flow to the second merging line when the maximum value is the fourth output flow rate.

[0026] The above recovery line includes a high-pressure accumulator for storing and discharging fluid and a confluence flow path connecting the high-pressure accumulator with the pump line, and a target actuator selection unit is provided for an operator to select a target actuator from the plurality of actuators, and the control unit can open and close the confluence flow path so that the fluid in the high-pressure accumulator flows into the pump line based on the total flow rate required by the pump when the target actuator is operated.

[0027] A construction machine according to the present invention comprises: a pump connected to an engine; a pump line through which a flow rate is discharged from the pump; a main control valve connecting the pump line to a plurality of actuators; a regeneration line connecting at least one of the plurality of actuators to the pump line; and a control unit determining a regeneration flow rate of the regeneration line according to a mode and controlling the pump; thereby improving performance and fuel efficiency.

[0028] Figure 1 is a front view showing a construction machine according to one embodiment of the present invention;

[0029] Figure 2 is a schematic diagram showing the hydraulic circuit in the construction machine of Figure 1.

[0030] Fig. 3 is a schematic diagram for explaining the operating principle of the hydraulic circuit of Fig. 2, and is a schematic diagram showing the flow rate in normal mode.

[0031] Fig. 4 is a schematic diagram for explaining the operating principle of the hydraulic circuit of Fig. 2, and is a schematic diagram showing the flow rate in the fuel economy mode during the regenerative mode.

[0032] Fig. 5 is a schematic diagram for explaining the operating principle of the hydraulic circuit of Fig. 2, and is a schematic diagram showing the flow rate in the performance mode during the regenerative mode.

[0033] Fig. 6 is a schematic diagram for explaining the operating principle of the hydraulic circuit of Fig. 2, and is a schematic diagram showing the flow rate in the composite mode during the regenerative mode.

[0034] Fig. 7 is a flowchart illustrating the logic for selecting a pump to be joined in the hydraulic circuit of Fig. 2.

[0035] Fig. 8 is a schematic diagram showing the flow of fluid in the hydraulic circuit of Fig. 2 during boom-down operation in normal mode.

[0036] Figure 9 is a schematic diagram showing the flow of fluid in the hydraulic circuit of Figure 2 when the fluid is stored in the high-pressure accumulator during boom-down operation in the regenerative mode.

[0037] Fig. 10 is a schematic diagram showing the flow of fluid in the hydraulic circuit of Fig. 2 when the fluid cannot be stored in the high-pressure accumulator during boom-down operation in regenerative mode;

[0038] Fig. 11 is a schematic diagram showing the flow of fluid in the hydraulic circuit of Fig. 2 when the fluid joins the pump without passing through the high-pressure accumulator during boom-down operation in regenerative mode.

[0039] Fig. 12 is a schematic diagram showing the flow of fluid in the hydraulic circuit of Fig. 2 during boom-up operation in normal mode.

[0040] Fig. 13 is a schematic diagram showing the flow of fluid in the hydraulic circuit of Fig. 2 during boom-up operation in regenerative mode.

[0041] Fig. 14 is a schematic diagram showing the flow of fluid in the hydraulic circuit of Fig. 2 during swing-acceleration operation in normal mode.

[0042] Fig. 15 is a schematic diagram showing the flow of fluid in the hydraulic circuit of Fig. 2 during swing-acceleration operation in regenerative mode.

[0043] Fig. 16 is a schematic diagram showing the flow of fluid in the hydraulic circuit of Fig. 2 during swing-deceleration operation in normal mode.

[0044] Fig. 17 is a schematic diagram showing the flow of fluid in the hydraulic circuit of Fig. 2 when the fluid is stored in the high-pressure accumulator during the swing-deceleration operation in the regenerative mode.

[0045] Figure 18 is a schematic diagram showing the flow of fluid in the hydraulic circuit of Figure 2 when the fluid cannot be stored in the high-pressure accumulator or is required to join the first pump during the swing-deceleration operation in the regenerative mode.

[0046] Fig. 19 is a schematic diagram showing the flow of fluid in the hydraulic circuit of Fig. 2 during jack-up operation in regenerative mode.

[0047] Fig. 20 is a schematic diagram showing the flow of fluid in the hydraulic circuit of Fig. 2 when idle in normal mode.

[0048] FIG. 21 is a flowchart illustrating a logic for determining the conditions and flow rate for joining fluid to a pump in a hydraulic circuit of a construction machine according to another embodiment of the present invention.

[0049] Fig. 22 is a schematic diagram for explaining the operating principle of a hydraulic circuit controlled according to the logic of Fig. 21, and is a schematic diagram showing the flow rate when the pump output is small and no merging occurs.

[0050] Fig. 23 is a schematic diagram for explaining the operating principle of a hydraulic circuit controlled according to the logic of Fig. 21, and is a schematic diagram showing the flow rate when the pump output is small but the operator wants merging to occur when the bucket actuator is operated.

[0051] Hereinafter, a construction machine according to the present invention will be described in detail with reference to the attached drawings.

[0052] FIG. 1 is a front view illustrating a construction machine according to one embodiment of the present invention, and FIG. 2 is a schematic diagram illustrating a hydraulic circuit in the construction machine of FIG. 1. FIGS. 3 to 6 are schematic diagrams for explaining the operating principles of the hydraulic circuit of FIG. 2. FIG. 7 is a flowchart illustrating the logic for selecting a pump to be joined in the hydraulic circuit of FIG. 2. FIGS. 8 to 20 are schematic diagrams illustrating the flow of fluid in the hydraulic circuit of FIG. 2 according to modes and operations.

[0053] Referring to FIG. 1, a construction machine according to one embodiment of the present invention may include a lower body (Uc) movable along the ground, an upper rotating body (Sw) rotatably provided on an upper portion of the lower body (Uc), a boom (Bm) rotatably coupled to the upper rotating body (Sw), an arm (Am) rotatably coupled to a tip end of the boom (Bm), a bucket (Bk) rotatably coupled to a tip end of the arm (Am), a hydraulic circuit for operating the upper rotating body (Sw), the boom (Bm), the arm (Am), and the bucket (Bk), and a control unit for controlling the hydraulic circuit.

[0054] Referring to FIG. 2, the hydraulic circuit may include a swing actuator (100) for rotating the upper rotor (Sw), a boom actuator (200) for rotating the boom (Bm), a pump (300) driven by receiving power from an engine (Eg), a main control valve (400) for transmitting fluid transported by the pump (300) to the swing actuator (100) and the boom actuator (200), a pump line (500) for connecting the pump (300) and the main control valve (400), a swing line (600) for connecting the main control valve (400) and the swing actuator (100), and a boom line (700) for connecting the main control valve (400) and the boom actuator (200).

[0055] The above swing actuator (100) may include a first opening (110) and a second opening (120) that are connected to each other and a rotor (130) that is connected to the upper rotating body (Sw) and rotates in one direction and the opposite direction depending on the direction of fluid flow between the first opening (110) and the second opening (120).

[0056] The boom actuator (200) may include a cylinder (210) connected to the upper rotating body (Sw), a piston (220) capable of reciprocating inside the cylinder (210), and a rod (230) extending from the piston (220) to the outside of the cylinder (210) and connected to the boom (Bm).

[0057] Here, the interior of the cylinder (210) is partitioned into a pair of chambers (240, 250) by the piston (220), and the pair of chambers (240, 250) may include a load chamber (250) in which the load (230) is received and a head chamber (240) which is an opposite chamber of the load chamber (250).

[0058] The above pump (300) may include a first pump (310) and a second pump (320) connected in parallel to the engine (Eg).

[0059] The above main control valve (400) may include a swing main control valve (410) for transmitting fluid to the swing actuator (100) and a boom main control valve (420) for transmitting fluid to the boom actuator (200).

[0060] The above pump line (500) may include a first pump line (510) that connects the first pump (310) and the swing main control valve (410) and a second pump line (520) that connects the second pump (320) and the boom main control valve (420).

[0061] The above swing line (600) includes a swing direction control valve (690) for controlling the flow direction of the fluid in the swing line (600), a first swing line (610) for connecting one side of the swing direction control valve (690) and the swing main control valve (410), a second swing line (620) for connecting the other side of the swing direction control valve (690) and the swing main control valve (410), a third swing line (630) for connecting the swing direction control valve (690) and the first opening (110) of the swing actuator (100), a fourth swing line (640) for connecting the swing direction control valve (690) and the second opening (120) of the swing actuator (100), and a third swing line (630) for connecting the third swing line (630) and the fourth swing line (640) without allowing the fluid to flow in from the third swing line (630) and the fourth swing line (640). It may include a fifth swing line (650) that allows fluid to be discharged through the swing line (640), a sixth swing line (660) that does not allow fluid to be discharged through the third swing line (630) and the fourth swing line (640) and allows fluid to flow in from the third swing line (630) and the fourth swing line (640), and a seventh swing line (670) that connects the fifth swing line (650) and the sixth swing line (660).

[0062] The above boom line (700) may include a head line (710) that connects the boom main control valve (420) and the head chamber (240), a load line (720) that connects the main control valve (400) and the load chamber (250), a cavitation line (730) that connects the head line (710) and the load line (720), and a cavitation valve (730v) that opens and closes the cavitation line (730).

[0063] Here, the hydraulic circuit according to the present embodiment may further include a recovery line (Reg) that connects at least one of the swing line (600) and the boom line (700) with the pump line (500).

[0064] Specifically, the recovery line (Reg) may include a swing recovery line (810) that is connected and shielded from the swing line (600) by the swing direction control valve (690), a swing recovery valve (810v) that opens and closes the swing recovery line (810), a low-pressure accumulator (820) for storing and discharging low-pressure fluid, a low-pressure accumulator line (830) that connects the low-pressure accumulator (820) to the swing recovery line (810), a low-pressure accumulator valve (830v) that opens and closes the low-pressure accumulator line (830), and a make-up line (840) that connects the low-pressure accumulator line (830) to the fifth swing line (650), the sixth swing line (660), and the seventh swing line (670).

[0065] In addition, the above recovery line (Reg) may further include a boom recovery line (910) branched from the cavitation line (730) and a boom recovery valve (910v) for opening and closing the boom recovery line (910).

[0066] In addition, the recovery line (Reg) may further include a first merging line (930) communicating with the first pump line (510), a first merging valve (930v) for opening and closing the first merging line (930), a second merging line (940) communicating with the second pump line (520), a second merging valve (940v) for opening and closing the second merging line (940), and a terminal line (920) for connecting the swing recovery line (810) and the boom recovery line (910) to the first merging line (930) and the second merging line (940).

[0067] In addition, the recovery line (Reg) may further include a high-pressure accumulator (950) for storing and discharging high-pressure fluid, a high-pressure accumulator line (960) for connecting the terminal line (920) and the high-pressure accumulator (950), and a high-pressure accumulator valve (960v) for opening and closing the high-pressure accumulator line (960).

[0068] In addition, the recovery line (Reg) may further include a tank (T) for storing the discharged fluid, a safety line (970) connecting the terminal line (920) and the tank (T), and a safety valve (970v) for opening and closing the safety line (970).

[0069] Here, the tank (T) can also be communicated with the main control valve (400) through a drain line (Dr).

[0070] In addition, the recovery line (Reg) may further include a third junction line (850) branched from the swing recovery line (810) and connected to the first pump line (510), and a third junction valve (850v) for opening and closing the third junction line (850).

[0071] The above control unit can be configured to improve fuel efficiency and performance by utilizing such a hydraulic circuit.

[0072] Specifically, if the flow rate of the fluid supplied to the main control valve (400) through the pump line (500) is referred to as the supply flow rate (Q_s1, Q_s2), the flow rate of the fluid supplied by the pump (300) to the pump line (500) is referred to as the pump flow rate (Q_p1, Q_p2), and the flow rate of the fluid supplied to the pump line (500) through the recovery line (Reg) is referred to as the recovery flow rate (Q_r1, Q_r2), then the control unit may be configured to determine the pump flow rates (Q_p1, Q_p2) from the difference between the supply flow rates (Q_s1, Q_s2) and the recovery flow rates (Q_r1, Q_r2) determined according to the mode and drive the pump (300).

[0073] Here, the supply flow rates (Q_s1, Q_s2) are the sum of the basic supply flow rates (Q_cmd1, Q_cmd2), which are the minimum flow rates required to operate the swing actuator (100) and the boom actuator (200), and the additional supply flow rates (Q_add1, Q_add2), which are flow rates exceeding the basic supply flow rates (Q_cmd1, Q_cmd2), and the basic supply flow rates (Q_cmd1, Q_cmd2) are determined according to the driver's input value, and the additional supply flow rates (Q_add1, Q_add2) are determined by multiplying the maximum regenerative flow rates (Q_max1, Q_max2), which are the maximum values ​​of the regenerative flow rates (Q_r1, Q_r2), by a predetermined performance constant, and the performance constant can be determined in the range of 0 to 1 depending on the mode.

[0074] In addition, the above-described recovery flow rates (Q_r1, Q_r2) are determined by multiplying the maximum recovery flow rates (Q_max1, Q_max2), which are the maximum values ​​of the above-described recovery flow rates (Q_r1, Q_r2), by a predetermined recovery constant, and the above-described recovery constant can be determined in the range of 0 to 1 depending on the mode.

[0075] More specifically, referring to FIG. 3, the driver can select a normal mode in which the regenerative line (Reg) is deactivated and input the basic supply flow rates (Q_cmd1, Q_cmd2) as 250 lpm (Q_cmd1: 100 lpm, Q_cmd2: 150 lpm) using the joystick. In this case, the performance constant is determined to be 0, so the additional supply flow rates (Q_add1, Q_add2) are determined to be 0 lpm (Q_add1: 0 lpm, Q_add2: 0 lpm), and the supply flow rates (Q_s1, Q_s2) can be determined to be 250 lpm (Q_s1: 100 lpm, Q_s2: 150 lpm). And, since the above recovery constant is determined to be 0, the above recovery flow rates (Q_r1, Q_r2) can be determined to be 0 lpm (Q_r1: 0 lpm, Q_r2: 0 lpm). Accordingly, the pump flow rates (Q_p1, Q_p2) are determined to be 250 lpm (Q_p1: 100 lpm, Q_p2: 150 lpm) obtained by subtracting the recovery flow rates (Q_r1, Q_r2) from the supply flow rates (Q_s1, Q_s2), and the pump (300) can be controlled to discharge the determined flow rates.

[0076] On the other hand, referring to FIG. 4, the driver can select a fuel efficiency mode among the regeneration modes in which the regeneration line (Reg) is activated and input the basic supply flow rates (Q_cmd1, Q_cmd2) as 250 lpm (Q_cmd1: 100 lpm, Q_cmd2: 150 lpm) using the joystick. In this case, the performance constant is determined to be 0, so the additional supply flow rates (Q_add1, Q_add2) are determined to be 0 lpm (Q_add1: 0 lpm, Q_add2: 0 lpm), and the supply flow rates (Q_s1, Q_s2) can be determined to be 250 lpm (Q_s1: 100 lpm, Q_s2: 150 lpm). Meanwhile, the above-described recovery constant is determined as the maximum value currently possible in the range of 0 to 1. Assuming that the maximum value currently possible among the above-described recovery constants is 1, and assuming that the maximum recovery flow rate (Q_max1, Q_max2) is 50 lpm, the recovery flow rate (Q_r1, Q_r2) can be determined as 50 lpm (Q_r1: 0 lpm, Q_r2: 50 lpm) obtained by multiplying the maximum recovery flow rate (Q_max1, Q_max2) by the recovery constant. Accordingly, the pump flow rate (Q_p1, Q_p2) is determined as 200 lpm (Q_p1: 100 lpm, Q_p2: 100 lpm) obtained by subtracting the recovery flow rate (Q_r1, Q_r2) from the supply flow rate (Q_s1, Q_s2), and the pump (300) can be controlled to discharge the determined flow rate. In this case, fuel efficiency can be improved as the energy required for the pump (300) is saved compared to the case of FIG. 3.

[0077] Alternatively, referring to FIG. 5, the driver can select a performance mode among the above regeneration modes and input the basic supply flow rate (Q_cmd1, Q_cmd2) as 250 lpm (Q_cmd1: 100 lpm, Q_cmd2: 150 lpm) using the joystick. In this case, the performance constant is determined as 1, and when the maximum regenerative flow rate (Q_max1, Q_max2) is assumed to be 50 lpm, the additional supply flow rate (Q_add1, Q_add2) is determined as 50 lpm (Q_add1: 0 lpm, Q_add2: 50 lpm), and the supply flow rate (Q_s1, Q_s2) can be determined as 300 pm (Q_s1: 100 lpm, Q_s2: 200 lpm) which is the sum of the additional supply flow rate (Q_add1, Q_add2) and the basic supply flow rate (Q_cmd1, Q_cmd2). Meanwhile, the above-described recovery constant is determined as the maximum value currently possible in the range of 0 to 1. If the maximum value currently possible among the above-described recovery constants is assumed to be 1, the recovery flow rate (Q_r1, Q_r2) can be determined as 50 lpm (Q_r1: 0 lpm, Q_r2: 50 lpm) which is obtained by multiplying the maximum recovery flow rate (Q_max1, Q_max2) by the recovery constant. Accordingly, the pump flow rate (Q_p1, Q_p2) is determined as 250 lpm (Q_p1: 100 lpm, Q_p2: 150 lpm) which is obtained by subtracting the recovery flow rate (Q_r1, Q_r2) from the supply flow rate (Q_s1, Q_s2), and the pump (300) can be controlled to discharge the determined flow rate. In this case, compared to the case of FIG. 3, the energy required for the pump (300) is the same, so there is no improvement in fuel efficiency, but the flow rate of the fluid supplied to the main control valve (400) increases, so that performance can be improved.

[0078] Alternatively, referring to FIG. 6, the driver may select a composite mode among the above regeneration modes and input the basic supply flow rate (Q_cmd1, Q_cmd2) as 250 lpm (Q_cmd1: 100 lpm, Q_cmd2: 150 lpm) using the joystick. In this case, the performance constant is determined as a value desired by the driver in a range greater than 0 and less than 1. Assuming that the driver desires 0.4 as the performance constant, and assuming that the maximum regenerative flow rate (Q_max1, Q_max2) is 50 lpm, the additional supply flow rate (Q_add1, Q_add2) is determined as 20 lpm (Q_add1: 0 lpm, Q_add2: 20 lpm), and the supply flow rate (Q_s1, Q_s2) can be determined as 270 pm (Q_s1: 100 lpm, Q_s2: 170 lpm) which is the sum of the additional supply flow rate (Q_add1, Q_add2) and the basic supply flow rate (Q_cmd1, Q_cmd2). Meanwhile, the above-described recovery constant is determined as the maximum value currently possible in the range of 0 to 1. If the maximum value currently possible among the above-described recovery constants is assumed to be 1, the recovery flow rate (Q_r1, Q_r2) can be determined as 50 lpm (Q_r1: 0 lpm, Q_r2: 50 lpm) which is obtained by multiplying the maximum recovery flow rate (Q_max1, Q_max2) by the recovery constant. Accordingly, the pump flow rate (Q_p1, Q_p2) is determined as 220 lpm (Q_p1: 100 lpm, Q_p2: 120 lpm) which is obtained by subtracting the recovery flow rate (Q_r1, Q_r2) from the supply flow rate (Q_s1, Q_s2), and the pump (300) can be controlled to discharge the determined flow rate. In this case, the fuel efficiency improvement effect is reduced compared to the case of Fig. 4, and the performance improvement effect is reduced compared to the case of Fig. 5, but the fuel efficiency and performance can be improved compared to the case of Fig. 3.

[0079] Meanwhile, in the case of FIGS. 4 to 6, it is assumed that the second joining line (940) is opened, but the control unit may be formed to open the line with the greater regeneration efficiency among the first joining line (930) and the second joining line (940).

[0080] That is, the control unit may be configured to compare the output (P1 Power) required for the first pump (310) with the output (P2 Power) required for the second pump (320) according to the logic illustrated in FIG. 7, and if the output (P1 Power) required for the first pump (310) is greater than the output (P2 Power) required for the second pump (320), open the first merging line (930) with the first merging valve (930v) and close the second merging line (940) with the second merging valve (940v), and if the output (P1 Power) required for the first pump (310) is less than the output (P2 Power) required for the second pump (320), close the first merging line (930) with the first merging valve (930v) and open the second merging line (940) with the second merging valve (940v).

[0081] Specifically, the logic illustrated in FIG. 7 includes a first pump information input step (S1) for receiving the pressure (p_p1) of the first pump (310) and the flow rate (Q_p1 cmd) required for the first pump (310); a first pump output calculation step (S4) for calculating the output (P1 Power) required for the first pump (310) by multiplying the pressure (p_p1) of the first pump (310) and the flow rate (Q_p1 cmd) required for the first pump (310); a second pump information input step (S5) for receiving the pressure (p_p2) of the second pump (320) and the flow rate (Q_p2 cmd) required for the second pump (320); A second pump output calculation step (S6) for calculating the output (P2 Power) required for the second pump (320) by multiplying the pressure (p_p2) of the second pump (320) and the flow rate (Q_p2 cmd) required for the second pump (320); A pump output comparison step (S7) for comparing the output (P1 Power) required for the first pump (310) and the output (P2 Power) required for the second pump (320); And, when the output (P1 Power) required for the first pump (310) is greater than the output (P2 Power) required for the second pump (320), the first merging line (930) is opened by the first merging valve (930v) and the second merging line (940) is closed by the second merging valve (940v), and when the output (P1 Power) required for the first pump (310) is less than the output (P2 Power) required for the second pump (320), the first merging line (930) is closed by the first merging valve (930v) and the second merging line (940) is opened by the second merging valve (940v), and the control unit may be configured to control the regenerative line (Reg) according to the logic.

[0082] Here, the logic may be configured such that a first pump flow rate comparison step (S2) is provided between the first pump information input step (S1) and the first pump output calculation step (S4) to compare the flow rate (Q_p1 cmd) required for the first pump (310) with a predetermined reference flow rate (e.g., 10 lpm), and the first pump output calculation step (S4) is executed when the flow rate (Q_p1 cmd) required for the first pump (310) is determined to be greater than the reference flow rate in the first pump flow rate comparison step (S2).

[0083] And, the logic may be configured to include a first pump pressure comparison step (S3) for comparing the pressure (p_p1) of the first pump (310) with a predetermined reference pressure (e.g., accumulator pressure (p_Accm.)) between the first pump information input step (S1) and the first pump output calculation step (S4), and to execute the first pump output calculation step (S4) when it is determined in the first pump pressure comparison step (S3) that the pressure (p_p1) of the first pump (310) is greater than the reference pressure.

[0084] And, the logic may be formed so that, if the first pump output calculation step (S4) is not executed, the output (P1 Power) required for the first pump (310) is considered to be smaller than the output (P2 Power) required for the second pump (320) in the pump output comparison step (S7), and the first merging line (930) is closed and the second merging line (940) is opened in the merging line selection step (S9).

[0085] In addition, the logic may be configured to include a mode confirmation step (S8) for confirming whether the driver has selected the regeneration mode between the pump output comparison step (S7) and the joining line selection step (S9), and to execute the joining line selection step (S9) when it is confirmed that the regeneration mode has been selected in the mode confirmation step (S8).

[0086] Meanwhile, the control unit may be configured to activate the regenerative line (Reg) when the driver has an intention to activate the regenerative line (Reg), activation of the regenerative line (Reg) is possible, and the operation performed is an operation with a high regenerative efficiency.

[0087] Specifically, there is a boom-down operation in which the piston (220) moves toward the head chamber (240) and the boom actuator (200) contracts, which is a frequently used operation by the user.

[0088] Referring to Fig. 8, when the driver selects the normal mode and performs a boom-down operation, the fluid in the head chamber (240) can flow to the main control valve (400) through the head line (710) by the load of the boom (Bm) applied through the load (230) and then be discharged to the tank (T) through the drain line (Dr). In addition, as the fluid discharged from the second pump (320) flows to the load chamber (250) through the second pump line (520), the main control valve (400) and the load line (720), cavitation of the load chamber (250) can be prevented.

[0089] On the other hand, referring to FIGS. 9 to 11, when the driver selects the regeneration mode and performs a boom-down operation, the cavitation valve (730v) opens the cavitation line (730), so that a portion of the fluid in the head line (710) flows through the cavitation line (730) to the load line (720), thereby preventing cavitation in the load chamber (250). Here, since there is no need to drive the second pump (320) to prevent cavitation in the load chamber (250), fuel efficiency can be improved compared to the case of FIG. 8.

[0090] And, the boom recovery valve (910v) opens the boom recovery line (910), so that the remainder of the fluid in the head line (710) can flow through the boom recovery line (910) to the terminal line (920) and then be stored in the high-pressure accumulator (950) or flow to the pump line (500). That is, as shown in FIGS. 9 and 10, the high-pressure accumulator valve (960v) opens the high-pressure accumulator line (960), so that at least a portion of the fluid in the terminal line (920) is stored in the high-pressure accumulator (950), and the fluid stored in the high-pressure accumulator (950) can be later discharged. Alternatively, as illustrated in FIG. 11, when the fluid cannot be stored in the high-pressure accumulator (950) or the required flow rate in the pump line (500) is large, the high-pressure accumulator valve (960v) closes the high-pressure accumulator line (960) and the merging valve opens the merging line, so that at least a portion of the fluid in the terminal line (920) can flow into the pump line (500) through the merging line. In this way, by regenerating the fluid in the boom line (700), fuel efficiency and / or performance can be improved compared to the case of FIG. 8. Here, in the case of FIG. 10, when the fluid cannot be stored in the high-pressure accumulator (950), the fluid in the head line (710) is discharged to the tank (T) through the main control valve and the drain line (Dr), thereby preventing the speed of the boom actuator (200) from becoming slower than the target speed when recovering the fluid in the boom line (700).

[0091] And, there is a boom-up motion in which the piston (220) moves toward the load chamber (250) and the boom actuator (200) extends, which is a motion frequently used by the user.

[0092] Referring to Fig. 12, when the driver selects the normal mode and performs a boom-up operation, the fluid discharged from the second pump (320) can flow into the head chamber (240) through the second pump line (520), the main control valve (400), and the head line (710). In addition, the fluid in the load chamber (250) can flow into the main control valve (400) through the load line (720) and then be discharged into the tank (T) through the drain line (Dr).

[0093] On the other hand, referring to FIG. 13, when the driver selects the regeneration mode and performs a boom-up operation, the high-pressure accumulator valve (960v) opens the high-pressure accumulator line (960), and the second merging valve (940v) opens the second merging line (940), so that the fluid of the high-pressure accumulator (950) flows to the second pump line (520) through the high-pressure accumulator line (960), the terminal line (920), and the second merging line (940), and the main control valve (400) can transfer the fluid received from the second pump (320) and the second merging line (940) through the second pump line (520) to the head chamber (240) through the head line (710). And, the fluid in the load chamber (250) can flow to the main control valve (400) through the load line (720) and then be discharged to the tank (T) through the drain line (Dr). In this case, by assisting the second pump (320) with the fluid stored in the high-pressure accumulator (950), fuel efficiency and / or performance can be improved compared to the case of FIG. 12.

[0094] And, there is a swing-acceleration motion in which the swing actuator (100) accelerates and a swing-deceleration motion in which the swing actuator (100) decelerates, which are motions frequently used by the user.

[0095] Referring to FIG. 14, when the driver selects the normal mode and performs the swing-acceleration operation, the main control valve (400) connects the first pump line (510) to the first swing line (610) and the second swing line (620) to the drain line (Dr), and the swing direction control valve (690) connects the first swing line (610) to the third swing line (630) and the fourth swing line (640) to the second swing line (620), so that the fluid discharged from the first pump (310) flows through the first pump line (510), the main control valve (400), the first swing line (610), the swing direction control valve (690), the third swing line (630), the first opening (110), the second opening (120), the fourth swing line (640), and the swing direction control valve (690). The fluid is discharged into the tank (T) sequentially passing through the valve (690), the second swing line (620), the main control valve (400) and the drain line (Dr), and the rotor (130) can be accelerated and rotated in one direction.

[0096] Here, although not shown, the main control valve (400) connects the first pump line (510) to the second swing line (620) and connects the first swing line (610) to the drain line (Dr), and the swing direction control valve (690) connects the second swing line (620) to the fourth swing line (640) and connects the third swing line (630) to the first swing line (610), so that the fluid discharged from the first pump (310) flows through the first pump line (510), the main control valve (400), the second swing line (620), the swing direction control valve (690), the fourth swing line (640), the second opening (120), the first opening (110), the third swing line (630), the swing direction control valve (690), the first swing line (610), and the It passes through the main control valve (400) and the drain line (Dr) sequentially and is discharged into the tank (T), and the rotor (130) can be accelerated and rotated in the opposite direction.

[0097] On the other hand, referring to FIG. 15, when the driver selects the regeneration mode and performs the swing-acceleration operation, the main control valve (400) connects the first pump line (510) to the first swing line (610), the swing direction control valve (690) connects the first swing line (610) to the third swing line (630) and connects the fourth swing line (640) to the swing regeneration line (810), and the low-pressure accumulator valve (830v) opens the low-pressure accumulator line (830), so that the fluid discharged from the first pump (310) flows through the first pump line (510), the main control valve (400), the first swing line (610), the swing direction control valve (690), the third swing line (630), the first opening (110), the second opening (120), and the fourth It passes sequentially through the swing line (640), the swing direction control valve (690), the swing recovery line (810) and the low-pressure accumulator line (830) and is stored in the low-pressure accumulator (820), and the rotor (130) can be accelerated and rotated in one direction.

[0098] Here, although not shown, the main control valve (400) connects the first pump line (510) to the second swing line (620), the swing direction control valve (690) connects the second swing line (620) to the fourth swing line (640) and connects the third swing line (630) to the swing recovery line (810), and the low-pressure accumulator valve (830v) opens the low-pressure accumulator line (830), so that the fluid discharged from the first pump (310) flows through the first pump line (510), the main control valve (400), the second swing line (620), the swing direction control valve (690), the fourth swing line (640), the second opening (120), the first opening (110), the third swing line (630), the swing direction control valve (690), and the swing It passes sequentially through the recovery line (810) and the low-pressure accumulator line (830) and is stored in the low-pressure accumulator (820), and the rotor (130) can be accelerated and rotated in the opposite direction.

[0099] And, referring to FIG. 16, when the driver selects the normal mode and performs the swing-deceleration operation, the fluid discharged from the second opening (120) sequentially passes through the fourth swing line (640), the sixth swing line (660), the seventh swing line (670), the fifth swing line (650), and the third swing line (630) and then flows into the first opening (110), and the rotor (130) can rotate at a deceleration rate in one direction.

[0100] Here, although not shown, when the fluid discharged from the first opening (110) sequentially passes through the third swing line (630), the sixth swing line (660), the seventh swing line (670), the fifth swing line (650), and the fourth swing line (640) and then flows into the second opening (120), the rotor (130) can be rotated at a reduced speed in the opposite direction.

[0101] On the other hand, referring to FIG. 17, when the driver selects the regeneration mode and performs a swing-deceleration operation, the swing direction control valve (690) connects the fourth swing line (640) with the swing regeneration line (810), the swing regeneration valve (810v) opens the swing regeneration line (810), and the high-pressure accumulator valve (960v) opens the high-pressure accumulator line (960), so that the fluid discharged from the second opening (120) sequentially passes through the fourth swing line (640), the swing direction control valve (690), the swing regeneration line (810), the terminal line (920), and the high-pressure accumulator line (960) and is stored in the high-pressure accumulator (950), and the rotor (130) can be decelerated and rotated in one direction. At this time, the low-pressure accumulator valve (830v) closes the low-pressure accumulator line (830), and the fluid of the low-pressure accumulator (820) can flow to the suction line of the swing actuator (100) among the swing lines (600) through the make-up line (840).

[0102] Here, although not shown, the swing direction control valve (690) connects the third swing line (630) with the swing regeneration line (810), the swing regeneration valve (810v) opens the swing regeneration line (810), and the high-pressure accumulator valve (960v) opens the high-pressure accumulator line (960), so that the fluid discharged from the first opening (110) sequentially passes through the third swing line (630), the swing direction control valve (690), the swing regeneration line (810), the terminal line (920), and the high-pressure accumulator line (960) and is stored in the high-pressure accumulator, and the rotor (130) can be decelerated and rotated in the opposite direction.

[0103] Meanwhile, when the fluid cannot be stored in the high-pressure accumulator (950) or the flow rate required for the first pump line (510) is large, as shown in FIG. 18, the third merging valve (850v) opens the third merging line (850), so that the fluid in the swing recovery line (810) can flow into the first pump line (510).

[0104] As shown in FIGS. 15, 17 and 18, when accelerating or decelerating a swing in the regenerative mode, the fluid in the swing line (600) is regenerated, thereby improving fuel efficiency and / or performance compared to when accelerating or decelerating a swing in the normal mode, as shown in FIGS. 14 and 16.

[0105] In addition, there is a jack-up operation that the user frequently uses to lift the construction machine by pressing the ground with the bucket (Bk), and during the jack-up operation, the pressure in the load chamber (250) must be rapidly increased and the fluid in the head chamber (240) must be rapidly decreased, which may be a condition that makes it difficult to perform the regeneration mode.

[0106] Accordingly, when the jack-up operation is executed, even if the driver has selected the regeneration mode, the operation is forcibly switched to the normal mode, and as illustrated in FIG. 19, the fluid discharged from the second pump (320) sequentially passes through the second pump line (520), the main control valve (400), and the load line (720) and flows into the load chamber (250), and the fluid in the head chamber (240) sequentially passes through the head line (710), the main control valve (400), and the drain line (Dr) and can be discharged into the tank (T).

[0107] And, when the jack-up operation is stopped, it can switch to the regenerative mode selected by the driver.

[0108] Meanwhile, when the driver selects the normal mode or turns the key off, as shown in FIG. 20, the high-pressure accumulator valve (960v) opens the high-pressure accumulator line (960), and the safety valve (970v) opens the safety line (970), so that the fluid in the high-pressure accumulator (950) is discharged into the tank (T), thereby ensuring system safety.

[0109] The construction machine of this embodiment according to this configuration can improve fuel efficiency and / or performance by regenerating fluid of at least one of the swing line (600) and the boom line (700) by having the hydraulic circuit having the recovery line (Reg) and the control unit controlling the same.

[0110] And, since the hydraulic circuit and the control unit are formed to determine the pump flow rates (Q_p1, Q_p2) from the difference between the supply flow rates (Q_s1, Q_s2) and the regenerative flow rates (Q_r1, Q_r2) determined according to the mode, fuel efficiency can be intensively improved, performance can be intensively improved, or fuel efficiency and performance can be improved at a desired ratio.

[0111] In addition, the hydraulic circuit and the control unit are configured to activate the regenerative line (Reg) when the driver intends to activate the regenerative line (Reg), the regenerative line (Reg) can be activated, and the operation performed is an operation with high regenerative efficiency, thereby effectively and efficiently improving fuel efficiency and / or performance.

[0112] In addition, the hydraulic circuit and the control unit are formed to open the first merging line (930) and the second merging line (940) having a higher regenerative efficiency, thereby maximizing fuel efficiency and / or performance improvement.

[0113] Meanwhile, the fuel efficiency improvement rate may vary depending on the conditions under which the fluid stored in the high-pressure accumulator (950) joins the pump line (500). That is, for example, when the fluid stored in the high-pressure accumulator (950) joins the pump line (500) when a movement primarily used by the operator is performed, fuel efficiency may be improved.

[0114] In consideration of this, it may be desirable for the control unit to be configured to open and close the high pressure accumulator line (960), the terminal line (920), the first merging line (930) and the second merging line (940) (hereinafter, merging flow paths (920, 930, 940, 960)) so that a predetermined flow rate flows from the high pressure accumulator (950) to the pump line (500) under predetermined conditions.

[0115] FIG. 21 is a flowchart illustrating a logic for determining a condition for joining fluid to a pump and a flow rate in a hydraulic circuit of a construction machine according to another embodiment of the present invention, FIG. 22 is a schematic diagram for explaining the operating principle of a hydraulic circuit controlled according to the logic of FIG. 21, and is a schematic diagram showing the flow rate when the output of the pump is small and joining does not occur, and FIG. 23 is a schematic diagram for explaining the operating principle of a hydraulic circuit controlled according to the logic of FIG. 21, and is a schematic diagram showing the flow rate when the output of the pump is small but the operator wants joining to occur when the bucket actuator is operated.

[0116] Referring to FIGS. 21 to 23, a construction machine according to another embodiment of the present invention may include a hydraulic circuit similar to the aforementioned embodiment.

[0117] Here, the hydraulic circuit further includes other actuators such as an arm actuator (1000) for rotating the arm (Am) and a bucket actuator (1100) for rotating the bucket (Bk), in addition to the swing actuator (100) and the boom actuator (200), and the other actuators can also be connected to the pump line (500) through the main control valve (400).

[0118] And, the operator can select a target actuator from a plurality of actuators through a target actuator selection unit, and the control unit can be configured to open the joining flow path (920, 930, 940, 960) when the target actuator operates under a predetermined condition. That is, in the case of the present embodiment, the worker may determine that the operation using the arm actuator (1000) and the bucket actuator (1100) is a mainly used operation, and may select the arm actuator (1000) and the bucket actuator (1100) as the target actuators, and the control unit may be configured to store at least one fluid among the swing line (600) and the boom line (700) in a high-pressure accumulator (950) and then open the junction flow path (920, 930, 940, 960) when at least one among the arm actuator (1000) and the bucket actuator (1100) is used.

[0119] Here, it is not desirable that the merging passage (920, 930, 940, 960) be unconditionally opened when at least one of the arm actuator (1000) and the bucket actuator (1100) is used, as the fuel efficiency is not improved. Accordingly, it may be desirable that the control unit be configured to control the merging passage (920, 930, 940, 960) by comprehensively considering the output of the pump (300), the pressure of the target actuator, the pressure of the high-pressure accumulator (950), and the operator's selection, as illustrated in FIG. 21.

[0120] Specifically, the control unit may be configured to open the confluence flow path (920, 930, 940, 960) when the output of the pump (300) is greater than a predetermined reference output (e.g., 50 kW).

[0121] And, the control unit may be configured to open the confluence passage (920, 930, 940, 960) when the pressure of the target actuator is greater than a predetermined reference pressure (e.g., 10 bar).

[0122] And, the control unit can be configured to open the merging flow path (920, 930, 940, 960) when the pressure of the high pressure accumulator (950) is greater than a predetermined value.

[0123] And, the operator may set a predetermined ratio for each of the target actuator and the pump (300), and the control unit may be configured to control the confluence flow path (920, 930, 940, 960) so that the maximum value among the calculated flow rates multiplied by the ratio to the maximum flow rate that can flow from the high-pressure accumulator (950) to the pump line (500) flows from the high-pressure accumulator (950) to the pump line (500).

[0124] And, when the target actuator includes a first target actuator communicating with the first pump line (510) and a second target actuator communicating with the second pump line (520), a first ratio for the first target actuator, a second ratio for the second target actuator, a third ratio for the first pump (310) and a fourth ratio for the second pump (320) are set by the operator, and the control unit multiplies the first ratio by the maximum flow rate that can flow from the high pressure accumulator (950) to the first pump line (510) for the operation of the first target actuator, a second ratio by the maximum flow rate that can flow from the high pressure accumulator (950) to the second pump line (520) for the operation of the second target actuator, and the operation of the first pump (310). It can be formed to produce a third output flow rate obtained by multiplying the third ratio by the maximum flow rate that can flow from the high pressure accumulator (950) to the first pump line (510) for the operation of the second pump (320), and a fourth output flow rate obtained by multiplying the fourth ratio by the maximum flow rate that can flow from the high pressure accumulator (950) to the second pump line (520) for the operation of the second pump (320).

[0125] And, the control unit may be configured to control the first merging line (930) and the second merging line (940) so that the maximum value among the first output flow rate, the second output flow rate, the third output flow rate, and the fourth output flow rate flows from the high-pressure accumulator (950) to the pump line (500).

[0126] That is, the control unit may be configured to control the first output flow rate to flow into the first merging line (930) when the maximum value is the first output flow rate, control the second output flow rate to flow into the second merging line (940) when the maximum value is the second output flow rate, control the third output flow rate to flow into the first merging line (930) when the maximum value is the third output flow rate, and control the fourth output flow rate to flow into the second merging line (940) when the maximum value is the fourth output flow rate.

[0127] According to this configuration, for example, in the situation of FIG. 22, even if a command is input to the bucket actuator (1100) and the arm actuator (1000) through the joystick, if the output of the pump (300) is lower than the reference pressure, the confluence path (920, 930, 940, 960) can be closed.

[0128] Alternatively, in the situation of FIG. 23, that is, if the operator desires forcible recovery to occur when the bucket actuator (1100) is operated even though the output of the pump (300) is lower than the reference pressure, the first merging line (930) may be opened and the second merging line (940) may be closed. Here, the flow rate flowing into the first pump line (510) through the first merging line (930) is determined according to the logic of FIG. 21, and 40 lpm is only an example.

[0129] Here, the fluid in the high-pressure accumulator does not join the pump line when the target actuator operates, but rather, when the flow rate is determined to be necessary from the perspective of the entire equipment when the target actuator operates, the fluid in the high-pressure accumulator joins the pump line. Accordingly, for example, when a user operates a bucket, the effect of the entire equipment moving smoothly can be felt rather than the effect of the bucket moving smoothly.

Claims

1. Pump connected to the engine; A pump line through which the flow is discharged from the above pump; A main control valve communicating the above pump line with a plurality of actuators; a recovery line connecting at least one of said plurality of actuators with said pump line; and A construction machine including a control unit that determines the regeneration flow rate of the regeneration line according to the mode and controls the pump.

2. In paragraph 1, The above plurality of actuators include a swing actuator and a boom actuator, A swing line connecting the main control valve and the swing actuator and a boom line connecting the main control valve and the boom actuator are provided. A construction machine in which the above recovery line connects at least one of the above swing line and the above boom fine with the above pump line.

3. In paragraph 2, A construction machine in which the control unit determines the pump flow rate from the difference between the supply flow rate and the regenerative flow rate determined according to the mode and controls to drive the pump, wherein the flow rate of the fluid supplied to the main control valve through the pump line is called the supply flow rate, the flow rate of the fluid supplied from the pump to the pump line is called the pump flow rate, and the flow rate of the fluid supplied to the pump line through the regenerative line is called the regenerative flow rate.

4. In paragraph 2, A construction machine characterized in that the supply flow rate, which is the flow rate of the fluid supplied to the main control valve through the pump line, is the sum of the basic supply flow rate determined according to the input value of the operator and the additional supply flow rate, which is the flow rate exceeding the basic supply flow rate.

5. In paragraph 2, The above additional supply flow rate is determined by multiplying the maximum regenerative flow rate, which is the maximum of the above regenerative flow rate, by a pre-determined performance constant. A construction machine in which the above performance constants are determined in the range of 0 to 1 depending on the mode.

6. In paragraph 2, In normal mode, the above recovery line is disabled, A construction machine in which the above regeneration line is activated when in regeneration mode.

7. In paragraph 2, A construction machine in which, when in fuel economy mode, the regenerative flow rate of the regenerative line increases, and the pump flow rate supplied by the pump to the pump line is reduced based on the increased regenerative flow rate.

8. In paragraph 2, A construction machine in which, when in performance mode, the regenerative flow rate of the regenerative line is increased and the pump flow rate supplied by the pump to the pump line is maintained.

9. In paragraph 2, A construction machine in which, in the case of a composite mode, the regenerative flow rate of the recovery line is increased according to a ratio determined in the composite mode, and the pump flow rate supplied to the pump line by the pump is decreased.

10. In paragraph 3, The above recovery flow rate is determined by multiplying the maximum recovery flow rate, which is the maximum value of the above recovery flow rate, by a previously determined recovery constant. A construction machine in which the above recovery constant is determined in the range of 0 to 1 depending on the mode.

11. In paragraph 10, In normal mode, the above recovery constant is determined as 0, A construction machine in which the regeneration constant is determined as the currently possible maximum value in the range of 0 to 1 when in regeneration mode.

12. In paragraph 1, The above recovery line comprises a high pressure accumulator for storing and discharging fluid and a junction line connecting the high pressure accumulator with the pump line, A construction machine wherein the above control unit opens and closes the merging flow path so that a predetermined flow rate flows from the high pressure accumulator to the pump line under predetermined conditions.

13. In paragraph 12, The worker selects a target actuator from the above multiple actuators, A construction machine wherein the above control unit opens the joining path when the above target actuator is operated under predetermined conditions.

14. In paragraph 13, When the pressure of the above target actuator is greater than a predetermined reference pressure, the above merging flow path is opened, When the pressure of the above target actuator is less than or equal to a predetermined reference pressure and the output of the above pump is greater than a predetermined reference output, the above merging flow path is opened. A construction machine in which the merging passage is opened when the pressure of the high pressure accumulator is greater than a predetermined value.

15. In paragraph 13, The above worker sets a predetermined ratio for each of the above target actuator and the above pump, A construction machine in which the control unit controls the merging flow path so that the maximum value among the calculated flow rates multiplied by the ratio to the maximum flow rate that can flow from the high pressure accumulator to the pump line flows from the high pressure accumulator to the pump line.

16. In paragraph 15, The above pump comprises a first pump and a second pump, The above pump line includes a first pump line communicating with the first pump and a second pump line communicating with the second pump, The above target actuators include a first target actuator communicating with the first pump line and a second target actuator communicating with the second pump line, A construction machine wherein the above-mentioned joining line comprises a first joining line communicating with the first pump line and a second joining line communicating with the second pump line.

17. In paragraph 16, A first ratio for the first target actuator, a second ratio for the second target actuator, a third ratio for the first pump and a fourth ratio for the second pump are set by the worker, The construction machine according to claim 1, wherein the control unit calculates a first output flow rate obtained by multiplying the first ratio by the maximum flow rate that can flow from the high pressure accumulator to the first pump line for the operation of the first target actuator, a second output flow rate obtained by multiplying the second ratio by the maximum flow rate that can flow from the high pressure accumulator to the second pump line for the operation of the second target actuator, a third output flow rate obtained by multiplying the third ratio by the maximum flow rate that can flow from the high pressure accumulator to the first pump line for the operation of the first pump, and a fourth output flow rate obtained by multiplying the fourth ratio by the maximum flow rate that can flow from the high pressure accumulator to the second pump line for the operation of the second pump.

18. In paragraph 17, A construction machine wherein the control unit controls the first merging line and the second merging line so that the maximum value among the first output flow rate, the second output flow rate, the third output flow rate and the fourth output flow rate flows from the high pressure accumulator to the pump line.

19. In Article 18, A construction machine wherein the control unit controls the first output flow rate to flow into the first merging line when the maximum value is the first output flow rate, controls the second output flow rate to flow into the second merging line when the maximum value is the second output flow rate, controls the third output flow rate to flow into the first merging line when the maximum value is the third output flow rate, and controls the fourth output flow rate to flow into the second merging line when the maximum value is the fourth output flow rate.

20. In paragraph 1, The above recovery line comprises a high pressure accumulator for storing and discharging fluid and a junction line connecting the high pressure accumulator with the pump line, A target actuator selection unit is provided for the worker to select a target actuator from the above-mentioned multiple actuators, A construction machine in which the above control unit opens and closes the merging flow path so that the fluid of the high pressure accumulator flows into the pump line based on the total flow rate required by the pump when the target actuator is operated.

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