JP2010070978A - Construction machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a construction machine capable of efficiently operating a plurality of arms even when a total power control is performed during a composite operation in which the plurality of arms are moved simultaneously. <P>SOLUTION: This construction machine has a first operation mode for operating an arm 5 by the pressure oil discharged from hydraulic pumps 10L, 10R or a secondary operation mode for operating a boom 4 by the pressure oil discharged from the hydraulic pump 10R while operating the arm 5 by the pressure oil discharged from the hydraulic pumps 10L, 10R. The absorption horsepower of the hydraulic pump 10R for operating the boom 4 when the total power control is performed in the second operation mode is reduced, and the absorption horsepower of the hydraulic pump 10L for operating the arm 5 by the reduced amount of the absorption horsepower is increased. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a construction machine that operates an arm body such as a boom, an arm, or a bucket while operating a hydraulic actuator by pressure oil discharged from a variable discharge hydraulic pump, and more particularly, a composite operation that operates a plurality of arm bodies simultaneously. In this case, the total horsepower control (meaning that the discharge amount of the hydraulic pump is controlled in accordance with the discharge pressure so that the absorption horsepower of the hydraulic pump does not exceed the output horsepower of the engine or electric motor) is performed. Even if it exists, it is related with the construction machine which operates an arm body efficiently.

Conventionally, in a complex operation in which a boom or bucket or the like is operated slowly using one of the two hydraulic pumps while quickly operating the arm using two hydraulic pumps, The upper limit of the discharge amount of the hydraulic pump is limited in inverse proportion to the operation amount of the boom or bucket, etc., and full horsepower control is applied to the discharge amount of both hydraulic pumps, and the discharge amount of the other hydraulic pump is the total horsepower. Hydraulic pressure that suppresses excessive heat generation due to pressure loss in the center bypass pipe line corresponding to one of the hydraulic pumps while suppressing a decrease in the operating speed of the arm by suppressing forced restriction by control A control device is known (see, for example, Patent Document 1).
JP 2007-23606 A

  However, the hydraulic control device described in Patent Document 1 changes according to the amount of arm operation so that there is no restriction on the discharge amount of both hydraulic pumps by full horsepower control even when the arm is operated quickly. Since the upper limit of the discharge amount of the hydraulic pump is limited, the operating speed of the arm is inevitably limited.

  On the other hand, the hydraulic control device described in Patent Document 1 regenerates the pressure oil from the contraction side to the extension side of the arm cylinder, thereby compensating for the lack of pressure oil flowing into the extension side and realizing the desired operating speed of the arm However, since the discharge amount of the hydraulic pump is limited while being inversely proportional to the operation amount of the boom or bucket, a decrease in the operability of the boom or bucket cannot be avoided.

  In view of the above-described points, the present invention provides a construction machine that efficiently operates a plurality of arm bodies even when full horsepower control is performed during a complex operation in which the plurality of arm bodies are operated simultaneously. The purpose is to do.

  In order to solve the above-described problem, the construction machine according to the first aspect of the invention includes a first operation mode in which only the first arm body is operated with the pressure oil discharged from the first hydraulic pump and the second hydraulic pump, or the A construction machine having a second operation mode in which the first arm body is operated by the pressure oil discharged from the second hydraulic pump while the first arm body is operated by the pressure oil discharged from the first and second hydraulic pumps. In the second operation mode, when the total horsepower control is performed by the first and second hydraulic pumps so as not to exceed the horsepower output by the drive source, the absorption horsepower of the second hydraulic pump is reduced. Absorption horsepower reducing means, and in the second operation mode, when the total horsepower control is performed by the first and second hydraulic pumps so as not to exceed the horsepower output by the drive source, the absorption horsepower of the first hydraulic pump Absorption horsepower increase means to increase , Characterized in that it comprises a.

  Further, the second invention is a construction machine according to the first invention, wherein an increase in the absorption horsepower by the absorption horsepower increasing means is equal to or less than a reduction in the absorption horsepower by the absorption horsepower reduction means. And

  The third invention is a construction machine according to the first or second invention, wherein, in the second operation mode, the absorption horsepower reducing means supplies the absorption horsepower of the second hydraulic pump to the second arm. It is set according to the amount of pressure oil required for the operation of the body and the amount of pressure oil joined to the first arm body.

  The fourth invention is a construction machine according to any one of the first to third inventions, wherein the absorption horsepower reducing means is based on a maximum discharge amount of the second hydraulic pump in the total horsepower control. The absorption horsepower is reduced by a predetermined amount, and the reduced absorption horsepower is gradually increased toward the maximum discharge amount of the second hydraulic pump in accordance with an increase in the amount of pressure oil necessary for the operation of the second arm body. The absorption horsepower of the second hydraulic pump is set to the above.

  With the above-described means, the present invention provides a construction machine that efficiently operates a plurality of arm bodies even when full horsepower control is performed during a complex operation in which the plurality of arm bodies are operated simultaneously. be able to.

  Embodiments of the present invention will be described below.

  FIG. 1 is a diagram showing a configuration example of a hydraulic excavator on which a construction machine hydraulic pump control device according to the present invention is mounted. In FIG. 1, an excavator 1 has an upper swing body 3 mounted on a crawler-type lower traveling body 2 via a swing mechanism so as to be rotatable around the X axis.

  The upper swing body 3 includes a boom 4, an arm 5 and a bucket 6, and a boom cylinder 7, an arm cylinder 8 and a bucket cylinder 9 as hydraulic actuators for driving the boom 4, the arm 5 and the bucket 6, respectively. Is provided.

  FIG. 2 is a hydraulic circuit diagram of a hydraulic pump control device mounted on a construction machine according to the present invention. The pump control device 100 is driven by an engine or an electric motor, and the discharge amount per rotation (cc / rev). ) Can be changed from two hydraulic pumps 10L, 10R to a center bypass pipe line 30L that communicates switching valves 11L, 12L, 13L, and 15L, or a center bypass that communicates switching valves 11R, 12R, 13R, 14 and 15R. Pressure oil is circulated to the pressure oil tank 22 through the pipe line 30R.

  The switching valve 11L is a spool valve that switches the flow of pressure oil so that the hydraulic oil discharged from the hydraulic pump 10L is circulated by the traveling hydraulic motor 42L.

  The switching valve 11 </ b> R is a traveling straight valve, and traveling hydraulic motors 42 </ b> L and 42 </ b> R that drive the lower traveling body 2 and any hydraulic actuator of the upper swing body 3 (e.g., boom cylinder 7, arm cylinder 8, bucket cylinder). 9 or the turning hydraulic motor 44) is operated at the same time, the hydraulic oil is circulated from the hydraulic pump 10L to the left and right traveling hydraulic motors 42L and 42R in order to improve the straight traveling performance of the lower traveling body 2. Therefore, it is a spool valve that switches the flow of pressure oil.

  The switching valve 12L is a spool valve that switches the flow of pressure oil in order to circulate the pressure oil discharged from the hydraulic pump 10L by the turning hydraulic motor 44. The switching valve 12R is a pressure oil discharged from the hydraulic pump 10R. Is a spool valve that switches the flow of pressure oil so that the hydraulic oil is circulated by the traveling hydraulic motor 42R.

  Further, the switching valves 13L and 13R supply pressure oil discharged from the hydraulic pumps 10L and 10R to the boom cylinder 7, respectively, and discharge the pressure oil in the boom cylinder 7 to the pressure oil tank 22. The switching valve 13R is a spool valve that switches when the boom operation lever 51 is operated (hereinafter referred to as “first speed boom switching valve 13R”), and the switching valve 13L is a spool valve that switches the flow. A spool valve (hereinafter referred to as “second speed boom switching valve 13L”) for joining the pressure oil discharged from the hydraulic pump 10L when the boom operation lever 51 is operated at a predetermined operation amount or more.

  The switching valve 14 is a spool valve for supplying the pressure oil discharged from the hydraulic pump 10 </ b> R to the bucket cylinder 9 and discharging the pressure oil in the bucket cylinder to the pressure oil tank 22.

  The switching valves 15L and 15R supply the pressure oil discharged from the hydraulic pumps 10L and 10R to the arm cylinder 8 and discharge the pressure oil in the arm cylinder 8 to the pressure oil tank 22, respectively. The switching valve 15L is a spool valve that operates when the arm operation lever 50 is operated (hereinafter referred to as “first speed arm switching valve 15L”), and the switching valve 15R is a spool valve that switches the flow. A spool valve (hereinafter referred to as “second speed arm switching valve 15R”) for joining the pressure oil discharged from the hydraulic pump 10R when the arm operation lever 50 is operated at a predetermined operation amount or more.

  The center bypass pipes 30L and 30R are respectively provided with negative control throttles 20L and 20R between the switching valves 15L and 15R located at the most downstream side and the pressure oil tank 22, and the flow of the pressure oil discharged by the hydraulic pumps 10L and 10R. Is a pressure oil line that generates a control pressure (hereinafter referred to as “negative control pressure”) for controlling the hydraulic pump regulators 40L and 40R upstream of the negative control throttles 20L and 20R.

  The control pressure lines 32L and 32R indicated by broken lines are control pressure lines for transmitting the negative control pressure generated upstream of the negative control throttles 20L and 20R to the hydraulic pump regulators 40L and 40R.

  Here, the hydraulic pump regulators 40L and 40R will be described with reference to FIG. 3 is an enlarged view of region III in FIG.

  The hydraulic pump regulator 40R includes a tilt actuator 41R for tilting and driving a swash plate (yoke) for changing the pump capacity of the hydraulic pump 10R to control the discharge amount of the hydraulic pump 10R, and the tilt actuator. A spool valve mechanism 60R for supplying and discharging pressure oil to 41R, a total horsepower control unit 53R for displacing the spool valve 600R of the spool valve mechanism 60R during full horsepower control, and a displacement of the spool valve 600R during negative control control This is a drive mechanism comprising a negative control unit 61R for causing the rotation and a feedback lever 62R for feeding back the drive displacement of the tilting actuator 41R to the spool valve 600R.

  The tilting actuator 41R corresponds to the operating piston 410R having the large diameter pressure receiving part PR1 at one end and the small diameter pressure receiving part PR2 at the other end, the pressure receiving chamber 411R corresponding to the large diameter pressure receiving part PR1, and the small diameter pressure receiving part PR2. The pressure receiving chamber 412R is configured such that the discharge pressure P2 of the hydraulic pump 10R is introduced into the pressure receiving chamber 411R through the spool valve 600R, or the pressure oil is discharged from the pressure receiving chamber 411R through the spool valve 600R. The discharge pressure P2 of the hydraulic pump 10R is introduced into 412R. When the pressure oil is introduced into the pressure receiving chamber 411R and displaced toward the pressure receiving chamber 412R, the operating piston 410R drives the swash plate (yoke) of the hydraulic pump 10R to tilt toward the small flow rate.

  The spool valve mechanism 60R has a first port into which the discharge pressure P2 of the hydraulic pump 10R is introduced, a second port that communicates with the pressure oil tank 22, and an output port that communicates with the pressure receiving chamber 411R. Spool valve that can be selectively switched to a first position that communicates with the port, a second position that communicates between the second port and the output port, or a neutral position where neither the first port nor the second port communicates with the output port 600R and a spring 601R that urges the spool valve 600R in a direction to displace it to the second position.

  The total horsepower control unit 53R includes a servo piston 530R that can be pressed in a direction in which the spool valve 600R is displaced to the first position, a spring 531R that returns the servo piston 530R from the pressed state, and a pressure receiving unit PR3 provided in the servo piston 530R. Corresponding to the pressure receiving chamber 532R into which the discharge pressure P2 of the hydraulic pump 10R is introduced, the pressure receiving chamber 533R into which the discharge pressure P1 of the hydraulic pump 10L is introduced corresponding to the pressure receiving portion PR4, and the electromagnetic wave described later corresponding to the pressure receiving portion PR5. A pressure receiving chamber 534R into which the control pressure of the proportional valve 55 is introduced.

  The negative control unit 61R includes a servo piston 610R that can be pressed in a direction to displace the spool valve 600R to the first position, a spring 611R that returns the servo piston 610R from the pressed state, and a pressure receiving unit PR6 provided in the servo piston 610R. Correspondingly, it comprises a pressure receiving chamber 612R into which the control pressure of the control pressure line 32R is introduced.

  In the feedback lever 62R, the spool valve 600R is switched to the first position or the second position by the displacement of the servo piston 530R or the servo piston 610R, pressure oil is introduced into the pressure receiving chamber 411R, or pressure oil is discharged from the pressure receiving chamber 411R. Thus, when the operating piston 410R moves, the movement amount is physically fed back to the spool valve 600R to return to the neutral position.

  The hydraulic pump regulator 40L includes a point where the discharge pressure P1 of the hydraulic pump 10L is introduced into the pressure receiving chamber 532L and a discharge pressure P2 of the hydraulic pump 10R is introduced into the pressure receiving chamber 533L in the total horsepower control unit 53L. In addition, the control pressure of the electromagnetic proportional valve 57 described later is introduced into the pressure receiving chamber 534R, but it is different from the hydraulic pump regulator 40R.

  With this configuration, the hydraulic pump regulators 40L and 40R are introduced by decreasing the discharge amount of the hydraulic pumps 10L and 10R as the control pressure introduced into the servo pistons 530L and 530R or the servo pistons 610L and 610R increases. The discharge amount of the hydraulic pumps 10L and 10R is increased as the control pressure is smaller.

  As shown in FIG. 2, when any hydraulic actuator in the excavator 1 is not used (hereinafter referred to as “standby mode”), the pressure oil discharged from the hydraulic pumps 10L, 10R is the center bypass pipe line 30L. , 30R to the negative control throttles 20L, 20R, and the negative control pressure generated upstream of the negative control throttles 20L, 20R is increased.

  As a result, the hydraulic pump regulators 40L and 40R displace the spool valves 600L and 600R to the first position by the negative control pressure introduced into the negative control units 61L and 61R, and drive the tilting actuators 41L and 41R. The discharge amount of the pumps 10L and 10R is decreased, and the pressure loss (pumping loss) when the discharged pressure oil passes through the center bypass pipe lines 30L and 30R is suppressed.

  On the other hand, as shown in FIGS. 5 to 9, when any hydraulic actuator in the hydraulic excavator 1 is used, the pressure oil discharged from the hydraulic pumps 10L and 10R passes through a switching valve corresponding to the hydraulic actuator. The amount of the negative control throttles 20L and 20R flowing into the hydraulic actuator is reduced or eliminated, and the negative control pressure generated upstream of the negative control throttles 20L and 20R is reduced.

  As a result, the hydraulic pump regulators 40L and 40R increase the discharge amount of the hydraulic pumps 10L and 10R, circulate sufficient pressure oil to each hydraulic actuator, and ensure the driving of each actuator.

  With the configuration as described above, the pump control device 100 causes wasteful energy consumption in the hydraulic pumps 10L and 10R (pressure oil discharged from the hydraulic pumps 10L and 10R is generated in the center bypass pipes 30L and 30R in the standby mode. When various hydraulic actuators are operated while suppressing (pumping loss), necessary and sufficient pressure oil can be supplied from the hydraulic pumps 10L and 10R to the various hydraulic actuators.

  The arm operating lever 50 uses the pressure oil discharged from the control pump 52 to apply a control pressure corresponding to the lever operating amount to the pilot port of the first speed arm switching valve 15L and the pilot port of the second speed arm switching valve 15R. It is a device that introduces the control pressure.

  Similarly to the arm operation lever 50, the boom operation lever 51 uses the pressure oil discharged from the control pump 52 to apply a control pressure corresponding to the lever operation amount to the pilot port of the first speed boom switching valve 13R and the second speed. This device introduces the control pressure to the pilot port of the boom switching valve 13L.

  The total horsepower control units 53L and 53R control the discharge amounts of the hydraulic pumps 10L and 10R according to the respective discharge pressures so that the total absorption horsepower of the hydraulic pumps 10L and 10R does not exceed the output horsepower of the engine or the electric motor. The spool valve of the hydraulic pump regulators 40L and 40R so that the hydraulic pumps 10L and 10R discharge the pressure oil with the discharge amounts Q1 and Q2 in response to the introduction of the discharge pressures P1 and P2 in the hydraulic pumps 10L and 10R. The tilt actuators 41L and 41R are driven by displacing 600L and 600R, and the swash plates (yokes) of the hydraulic pumps 10L and 10R are tilt-driven. The relationship between the discharge pressures P1 and P2 and the discharge amounts Q1 and Q2 is a predetermined P (discharge pressure) -Q (discharge amount) diagram (hereinafter, “normal P-Q diagram”). ) In advance.

  FIG. 4 is a PQ diagram showing the characteristics of the total horsepower control, and FIG. 4A is a normal PQ diagram applied to both the hydraulic pumps 10L and 10R. FIG. 4B is an example of an absorption horsepower reduction PQ diagram used by an absorption horsepower reduction unit described later, and FIG. 4C shows an absorption horsepower increase PQ used by an absorption horsepower increase unit described later. It is an example of a diagram.

  As shown in FIG. 4A, for example, the lever operation amount of the arm operation lever 50 becomes a predetermined value or more, and the negative control pressure upstream of the negative control throttle 20L becomes less than the predetermined value (the maximum discharge amount is set to the hydraulic pump 10L). When the control of the discharge amount of the hydraulic pump 10L shifts from the control by the negative control pressure to the control by the total horsepower control unit 53L, the discharge pressure P of the hydraulic pump 10L is P1, and the discharge pressure of the hydraulic pump 10R Is equal to P2, the total horsepower control unit 53L responds to the tilting actuator 41L of the hydraulic pump regulator 40L so that the discharge amount Q of the hydraulic pump 10L becomes Q1 (= Q2) at (P1 + P2) / 2. Supply the pressure oil.

  Further, the control of the discharge amount of the hydraulic pump 10R also shifts from the control by the negative control pressure to the control by the total horsepower control unit 53R, and if the discharge pressure P of the hydraulic pump 10L is P1 and the discharge pressure P of the hydraulic pump 10R is P2, The total horsepower control unit 53R supplies a corresponding control pressure to the tilting actuator 41R of the hydraulic pump regulator 40R so that the discharge amount Q of the hydraulic pump 10R becomes Q2 (= Q1) at (P1 + P2) / 2. .

  The main controller 54 is a computer including a CPU (Central Processing Unit), a RAM (Random Access Memory), a ROM (Read Only Memory), etc., and stores a program corresponding to the absorption horsepower reducing means in the ROM while absorbing the horsepower. The CPU is caused to execute processing corresponding to the reduction means.

  Further, the main controller 54 measures the control pressure generated when the arm operation lever 50 is operated in the upward direction, and the pressure sensor S1 that measures the control pressure generated when the arm operation lever 50 is operated in the upward direction. The lever operation amount of the arm operation lever 50 is detected based on the output of the pressure sensor S2.

  Similarly, the main controller 54 measures the control pressure generated when the boom operation lever 51 is operated in the upward direction, and the pressure sensor S3 that measures the control pressure generated when the boom operation lever 51 is operated in the upward direction. The lever operation amount of the boom operation lever 51 is detected based on the output of the pressure sensor S4 to be measured.

  Further, the main controller 54 discharges the pressure oil in the hydraulic pumps 10L and 10R based on the outputs of the pressure sensor S5 that measures the discharge pressure of the hydraulic pump 10L and the pressure sensor S6 that measures the discharge pressure of the hydraulic pump 10R. Is detected.

  The absorption horsepower reducing means is a case where the operation content of the excavation attachment is determined based on the outputs of the pressure sensors S1 to S6, and it is determined that a predetermined combined operation has been performed, and the discharge amounts of the hydraulic pumps 10L, 10R are all This is a means for reducing the absorption horsepower of the hydraulic pump 10R when controlled by the horsepower control units 53L and 53R, for example, a hydraulic pump for quickly operating the arm 5 by pressure oil discharged from the hydraulic pump 10L. When the discharge amounts of 10L and 10R are controlled by the total horsepower control units 53L and 53R and the boom 4 is operated slowly by the pressure oil discharged by the hydraulic pump 10R, the discharge amount Q of the hydraulic pump 10R is absorbed. A control current is supplied to the proportional solenoid valve 55 so that it is in accordance with the PQ diagram when the horsepower is reduced. So as to provide adequate pressure oil to the tilting actuator 41R of motor 40R.

  Here, the electromagnetic proportional valve 55 is a valve for adjusting the control pressure introduced from the control pump 52 into the pressure receiving chamber 534R of the total horsepower control unit 53R in accordance with the control current output from the main controller 54. The control pressure at the intermediate value between the minimum value and the maximum value of the control current 55 is introduced as a reference control pressure into the pressure receiving chamber 534R of the total horsepower control unit 53R, and the control pressure decreases as the control current increases. It has become. Further, it is assumed that a plurality of PQ diagrams at the time of absorption horsepower reduction are prepared according to the lever operation amount of the boom operation lever 51 and are registered in advance in the ROM or the like of the main controller 54.

  FIG. 4B shows the PQ diagram at the time of absorption horsepower reduction by a solid line, and the normal PQ diagram by a broken line. When the discharge pressure P of the hydraulic pump 10L is P1 and the discharge pressure P of the hydraulic pump 10R is P2, the discharge amount Q of the hydraulic pump 10R is normally set to a normal PQ diagram by the total horsepower control unit 53R. Is controlled to be Q2 (= Q1) at (P1 + P2) / 2 along the line, but when a predetermined combined operation is performed, the absorption horsepower reduction means reduces the discharge horsepower of the hydraulic pump 10R to the absorption horsepower A control current is supplied to the electromagnetic proportional valve 55 to introduce a control pressure into the pressure receiving chamber 534R of the total horsepower control unit 53R so that the discharge amount QT2 (QT2 <Q2) along the time PQ diagram is obtained. Thus, by offsetting the servo piston 530R of the total horsepower control unit 53R as if a discharge pressure higher than the discharge pressure (P1 + P2) / 2 is apparently generated, the corresponding pressure oil is supplied to the hydraulic pump regulator 40. It is introduced into the R tilting actuator 41R.

  In this way, the absorption horsepower reducing means can reduce the absorption horsepower of the hydraulic pump 10R and suppress the generation of useless pressure loss. Note that the gray area AR1 in FIG. 4B represents the amount of reduction in absorption horsepower in the hydraulic pump 10R by the absorption horsepower reduction means.

  The absorption horsepower increase means is means for increasing the absorption horsepower of the other hydraulic pump when the absorption horsepower of one hydraulic pump is reduced by the absorption horsepower reduction means. For example, the absorption horsepower reduction means When the discharge amount of 10R is reduced so as to be along the PQ diagram when the absorption horsepower is reduced, the discharge amount Q of the hydraulic pump 10L is along the PQ diagram when the absorption horsepower is increased. As described above, the control current is supplied to the electromagnetic proportional valve 57 so that the appropriate pressure oil is supplied to the tilting actuator 41L of the hydraulic pump regulator 40L.

  Here, the electromagnetic proportional valve 57 is a valve for adjusting the control pressure introduced from the control pump 52 to the pressure receiving chamber 534L of the total horsepower control unit 53L in accordance with the control current output from the main controller 54. The control pressure at the intermediate value between the minimum value and the maximum value of the control current 57 is introduced into the pressure receiving chamber 534L of the total horsepower control unit 53L as a reference control pressure, and the control pressure decreases as the control current increases. It has become. Further, it is assumed that a plurality of PQ diagrams at the time of absorption horsepower increase are prepared so as to be paired with a PQ diagram at the time of absorption horsepower reduction, and are registered in advance in the ROM or the like of the main controller 54.

  FIG. 4C shows a PQ diagram at the time of increased absorption horsepower by a solid line, and a normal PQ diagram by a broken line. When the discharge pressure P of the hydraulic pump 10L is P1 and the discharge pressure P of the hydraulic pump 10R is P2, the discharge amount Q of the hydraulic pump 10L is normally set to a normal PQ diagram by the total horsepower control unit 53L. Is controlled so that Q1 (= Q2) at (P1 + P2) / 2 along the line, but when a predetermined combined operation is performed, the absorption horsepower increasing means is configured such that the discharge amount Q of the hydraulic pump 10L increases the absorption horsepower. The control current is supplied to the electromagnetic proportional valve 57 so that the discharge amount QT1 (QT1> Q1 = Q2) along the time PQ diagram is obtained, and the control pressure is introduced into the pressure receiving chamber 534L of the total horsepower control unit 53L. By offsetting the servo piston 530L of the total horsepower control unit 53L as if a discharge pressure lower than the discharge pressure (P1 + P2) / 2 is apparently generated, the corresponding pressure oil is used for the hydraulic pump. Regi It is introduced into the tilting actuator 41L of regulator 40L.

  In this way, the absorption horsepower increasing means increases the absorption horsepower of the hydraulic pump 10L by the amount corresponding to the reduction of the absorption horsepower in the hydraulic pump 10R reduced by the absorption horsepower reduction means so as not to exceed the output horsepower of the drive source. However, the arm 5 can be operated more quickly.

  The gray area AR2 in FIG. 4C represents the increase in absorption horsepower in the hydraulic pump 10L by the absorption horsepower increasing means, and is the same size as AR1 indicating the decrease in absorption horsepower in the hydraulic pump 10R by the absorption horsepower reduction means. It means that it is.

  Next, the state of the pump control apparatus 100 during arm single operation will be described with reference to FIG.

  FIG. 5 shows a state of the pump control device 100 when the arm operation lever 50 is tilted to the maximum in the downward direction. The hydraulic pump 10L is controlled by the first horsepower control valve 15L under the control of the total horsepower control unit 53L. The pressure oil in the arm cylinder 8 is discharged from the rod side of the arm cylinder 8 to the pressure oil tank 22 while supplying the pressure oil with the maximum discharge amount to the head side of the arm cylinder 8 via the hydraulic pump 10R. The pressure oil mainly passing through the center bypass conduit 30R is joined to the head side of the arm cylinder 8 via the second speed arm switching valve 15R (first operation mode).

  Next, the state of the pump control apparatus 100 when various composite operations are performed will be described with reference to FIGS.

  FIG. 6 shows the state of the pump control device 100 when the arm operation lever 50 is tilted to the maximum in the downward direction and the boom operation lever 51 is slightly tilted in the upward direction. Under the control of the control unit 53L, pressure oil is supplied to the head side of the arm cylinder 8 with the maximum discharge amount via the first speed arm switching valve 15L, and the pressure oil in the arm cylinder 8 is pressurized from the rod side of the arm cylinder 8 to pressure oil. It is discharged to the tank 22.

  The hydraulic pump 10R supplies pressure oil to the head side of the boom cylinder 7 through the first speed boom switching valve 13R at the maximum discharge amount under the control of the total horsepower control unit 53R, and from the rod side of the boom cylinder 7 The pressure oil in the boom cylinder 7 is discharged to the pressure oil tank 22, and at the same time, the pressure oil mainly passing through the parallel circuit 31R is joined to the head side of the arm cylinder 8 via the second speed arm switching valve 15R.

  As a result, the excavator 1 performs an operation (second operation mode) of rapidly lowering (embracing) the arm 5 while slowly raising (raising) the boom 4.

  In this case, since the lever operation amount of the arm operation lever 50 is large, not only the hydraulic pump 10L but also the hydraulic pump 10R tries to flow the pressure oil into the head side of the arm cylinder 8, but the load pressure of the arm cylinder 8 is increased by the boom. When the pressure is lower than the load pressure of the cylinder 7, almost all of the pressure oil discharged from the hydraulic pump 10R flows into the head side of the arm cylinder 8. In order to prevent this, a throttle 23 (which may be disposed inside the second speed arm switching valve 15R) is provided in the parallel circuit 31R toward the second speed arm switching valve 15R, and the head side of the arm cylinder 8 is provided. Although the flow rate of the inflowing pressure oil is limited, a wasteful pressure loss is generated at the throttle 23 (the location where the pressure loss is generated is indicated by a broken line circle C1).

  Further, the total horsepower control units 53L and 53R control the total horsepower so that the total discharge horsepower of the hydraulic pumps 10L and 10R does not exceed the output horsepower of the engine, so that the total horsepower is controlled. Since the discharge amount increases with respect to the required pressure oil, in the region where the spool opening is small in the first speed boom switching valve 13R, a wasteful pressure loss is also generated here (where the pressure loss occurs). Is indicated by broken-line circles C2 and C3, since the first speed boom switching valve 13R is throttled for other combined operations, the pressure loss is further greater.

  FIG. 7 shows the state of the pump control device 100 when the absorption horsepower reducing means is operated in order to suppress the occurrence of useless pressure loss in the state of FIG. 6. The absorption horsepower reducing means of the main controller 54 is Based on the output of the pressure sensor S2, it is detected that the arm operating lever 50 is tilted in the downward direction as much as possible (the second arm switching valve 15R is actuated), and the output of the pressure sensor S3 is detected. When the boom operating lever 51 is detected to be tilted in the upward direction based on the absorption horsepower reduction PQ diagram (see FIG. 4B) according to the lever operating amount of the boom operating lever 50. While being used, the control current is supplied to the electromagnetic proportional valve 55 so that the actual discharge amount of the hydraulic pump 10R becomes QT2 (QT2 <Q2).

  Further, the absorption horsepower increase means of the main controller 54 is configured to reduce the absorption horsepower PQ when the discharge amount of the hydraulic pump 10R is reduced by the absorption horsepower reduction means (when the control current is supplied to the electromagnetic proportional valve 55). The actual discharge amount of the hydraulic pump 10L is QT1 (QT1> Q1) while using the PQ diagram (see FIG. 4C) when the absorption horsepower increases corresponding to the diagram (see FIG. 4B). ), A control current is supplied to the electromagnetic proportional valve 57.

As a result, the pump control apparatus 100 supplies the pressure oil to the arm cylinder 8 using the maximum discharge amount QT1 of the hydraulic pump 10L and a part of the discharge amount QT2 of the hydraulic pump 10R (the amount that passes through the second speed arm switching valve 15R). At the same time, the arm 5 is quickly moved downward (in the holding direction), and at the same time, the remainder of the discharge amount QT2 of the hydraulic pump 10R (excluding the amount passing through the second speed arm switching valve 15R) The second speed arm does not cause the engine to stop by absorbing horsepower exceeding the output horsepower of the engine while causing the hydraulic oil to flow into the head side of the boom cylinder 7 and slowly moving the boom 4 in the direction of raising (raising). Generation of useless pressure loss in the throttle 23 of the parallel circuit 31R toward the switching valve 15R can be suppressed.

  The discharge amount QT2 of the hydraulic pump 10R decreases to the discharge amount QT2 that compensates for the amount of passage corresponding to the lever operation amount of the boom operation lever 51 that passes through the second speed arm switching valve 15R. This does not affect the operating speed of the arm 5 significantly.

  On the other hand, since the discharge amount Q of the hydraulic pump 10L increases to the discharge amount QT1, the arm 5 can be operated in the lowering direction (the holding direction) more quickly.

  FIG. 8 shows a state of the pump control device 100 when the arm operation lever 50 is tilted to the maximum in the downward direction and the bucket operation lever 56 is tilted in the downward direction. The hydraulic pump 10L includes the total horsepower control unit. Under the control of 53L, the pressure oil is supplied at the maximum discharge amount to the head side of the arm cylinder 8 through the first speed arm switching valve 15L, and the pressure oil in the arm cylinder 8 is supplied from the rod side of the arm cylinder 8 to the pressure oil tank 22. Is discharged.

  The hydraulic pump 10R supplies pressure oil to the head side of the bucket cylinder 9 via the bucket switching valve 14 at a maximum discharge amount under the control of the total horsepower control unit 53R, and from the rod side of the bucket cylinder 9 to the bucket cylinder 9 The pressure oil inside is discharged to the pressure oil tank 22, and at the same time, the pressure oil mainly passing through the parallel circuit 31R is joined to the head side of the arm cylinder 8 via the second speed arm switching valve 15R.

  As a result, the excavator 1 performs an operation (second operation mode) in which the arm 5 is quickly lowered (embraced) while the bucket 6 is slowly lowered.

  In this case, since the lever operation amount of the arm operation lever 50 is large, the pump control device 100 tries to flow the pressure oil from the hydraulic pump 10R to the head side of the arm cylinder 8 as well as the hydraulic pump 10L. When the load pressure of the arm cylinder 8 is lower than the load pressure of the bucket cylinder 9 as in the air, almost all of the pressure oil discharged from the hydraulic pump 10R flows into the head side of the arm cylinder 8. Become. In order to prevent this, a throttle 23 (which may be disposed inside the second speed arm switching valve 15R) is provided in the parallel circuit 31R toward the second speed arm switching valve 15R, and the head side of the arm cylinder 8 is provided. Although the flow rate of the inflowing pressure oil is limited, a wasteful pressure loss is generated at the throttle 23 (the location where the pressure loss is generated is indicated by a broken line circle C1).

  Further, the total horsepower control units 53L and 53R control the total horsepower so that the total discharge horsepower of the hydraulic pumps 10L and 10R does not exceed the output horsepower of the engine, so that the total horsepower is controlled. Since the discharge amount increases with respect to the required pressure oil, in the region where the spool opening is small in the bucket switching valve 14, a wasteful pressure loss is also generated here (the location where the pressure loss is generated is indicated by a broken line circle). C4 and C5).

  FIG. 9 shows a state of the pump control device 100 when the absorption horsepower reducing means is operated in order to suppress the occurrence of useless pressure loss in the state of FIG. 8, and the absorption horsepower reducing means of the main controller 54 is Based on the output of the sensor S2, it is detected that the arm operating lever 50 has been tilted in the downward direction to the maximum extent (to the extent that the second arm switching valve 15R is actuated), and based on the output of the pressure sensor S8. When it is detected that the bucket operating lever 56 is tilted in the downward direction, the PQ diagram (see FIG. 4B) when reducing the absorption horsepower according to the lever operating amount of the bucket operating lever 56 is used. However, the control current is supplied to the electromagnetic proportional valve 55 so that the actual discharge amount of the hydraulic pump 10R becomes QT2 (QT2 <Q2).

  Further, the absorption horsepower increasing means of the main controller 54 corresponds to the PQ diagram (see FIG. 4B) when the absorption horsepower is reduced when the discharge amount of the hydraulic pump 10R is reduced by the absorption horsepower reducing means. A control current is supplied to the electromagnetic proportional valve 57 so that the actual discharge amount of the hydraulic pump 10L becomes QT1 (QT1> Q1) while using the PQ diagram (see FIG. 4C) when the absorption horsepower is increased. Supply.

  As a result, the pump control apparatus 100 supplies pressure oil to the arm cylinder 8 using the discharge amount QT1 of the hydraulic pump 10L and a part of the discharge amount QT2 of the hydraulic pump 10R (the amount that passes through the second speed arm switching valve 15R). At the same time that the arm 5 is caused to flow into the head side and the arm 5 is quickly moved downward (in the holding direction), the remaining amount of the discharge amount QT2 of the hydraulic pump 10R (excluding the amount passing through the second speed arm switching valve 15R). Switch the second speed arm without causing the engine to stop by absorbing horsepower exceeding the engine's output horsepower while allowing the pressure oil to flow into the head side of the bucket cylinder 9 and slowly moving the bucket 6 in the direction of raising (raising direction). Generation of useless pressure loss in the throttle 23 of the parallel circuit 31R directed to the valve 15R can be suppressed.

  Note that the discharge amount QT2 of the hydraulic pump 10R decreases to a discharge amount QT2 that compensates for the amount of passage according to the lever operation amount of the bucket operation lever 56 that passes through the second speed arm switching valve 15R. This does not have a great influence on the operation speed of the bucket 6.

  On the other hand, since the discharge amount Q of the hydraulic pump 10L increases to the discharge amount QT1, the arm 5 can be operated in the lowering direction (the holding direction) more quickly.

  Although the embodiment of the present invention has been described in detail above, the present invention is not limited to the specific embodiment, and various modifications and changes are within the scope of the gist of the present invention described in the claims. It can be changed.

  For example, in the above-described embodiment, the bucket 6 is illustrated as an example. However, instead of this, a lifting magnet may be used.

  In the above-described embodiment, the pump control device 100 increases the absorption horsepower in the hydraulic pump 10L by the absorption horsepower increase means by the same amount as the reduction of the absorption horsepower in the hydraulic pump 10R by the absorption horsepower reduction means. However, the increase may be any size as long as it does not exceed the decrease, and may be adjusted according to the lever operation amount of the arm operation lever 50.

  In the above-described embodiment, the pump control device 100 is preliminarily configured such as a ROM so that the discharge amount according to the lever operation amount of the boom operation lever 51 or the discharge amount according to the lever operation amount of the bucket operation lever 56 is obtained. However, instead of this, adjustment is made using the PQ diagram at the time of absorption horsepower reduction, but instead of this, a reference reduction discharge that first reduces the discharge amount of the hydraulic pump 10R by a predetermined amount (for example, 20%). An amount is set, and the reference reduced discharge amount is gradually increased toward the maximum discharge amount according to an increase in the lever operation amount of the boom operation lever 51 or according to an increase in the lever operation amount of the bucket operation lever 56. May be.

  Further, in the above-described embodiment, each of the total horsepower controllers 53L and 53R is provided with another pressure receiving chamber 535L and 535R, and pressure oil is supplied to the pressure receiving chambers 535L and 535R via another electromagnetic proportional valve 58. Thus, for example, it is possible to coexist with a horsepower control mechanism capable of increasing or decreasing the flow rates of the hydraulic pumps 10L and 10R by the same amount according to the engine speed (see FIG. 10).

  In addition, by using the switching valve 59, the pump control apparatus 100 normally introduces the control pressure of the electromagnetic valve 57 to both the total horsepower control units 53L and 53R as a horsepower control mechanism, and when the absorption horsepower is reduced, The control pressure of the electromagnetic valve 57 may be introduced into the horsepower control unit 53L, and the control pressure of the electromagnetic valve 55 may be introduced into the total horsepower control unit 53R (see FIG. 11). In addition, the pump control apparatus 100 is provided with a servo piston for a horsepower control mechanism different from the servo pistons 530L and 530R in each of the total horsepower controllers 53L and 53R, and performs the horsepower control and the absorption horsepower control separately. You may do it.

  Furthermore, the pump control device 100 uses the shuttle valve 65 instead of the configuration shown in FIG. 11 to selectively receive the negative control pressure of the control pressure line 32R and the control pressure of the electromagnetic proportional valve 55 by the negative control unit 61. It may be configured to be introduced into the chamber 612R (see FIG. 12).

  In the above-described embodiment, the pump control device 100 configures the total horsepower control units 53L and 53R using the servo pistons 530L and 530R that are displaced according to the discharge pressures P1 and P2 of the hydraulic pumps 10L and 10R. However, instead of this, sensors for detecting the discharge pressures P1, P2 of the hydraulic pumps 10L, 10R are provided, and the main controller 54 determines the target displacement amount of the spool valve 600R in the spool valve mechanism 60R based on these detected values. The spool valve 600R may be configured to be driven, and the correction by the absorption horsepower reducing means may be performed when the main controller 54 sets the target displacement amount of the spool valve 600R.

  Further, in the above-described embodiment, the pump control device 100 illustrates the parallel circuit 31R that is provided with the throttle 23 toward the second speed arm switching valve 15R, but instead of this, the second speed arm switching is performed. A throttle may be provided inside the valve 15R.

It is a figure which shows the structural example of a hydraulic shovel. 1 is a hydraulic circuit diagram of a pump control device mounted on a construction machine according to the present invention. It is an enlarged view of the area | region III of FIG. It is a PQ diagram which shows the characteristic of total horsepower control. It is a figure which shows the state of the pump control apparatus at the time of operating an arm independently. It is a figure (the 1) which shows the state of the pump control apparatus at the time of carrying out compound operation of an arm and a boom. It is FIG. (2) which shows the state of the pump control apparatus at the time of carrying out compound operation of an arm and a boom. It is a figure (the 1) which shows the state of the pump control apparatus at the time of carrying out compound operation of an arm and a bucket. It is a figure (the 2) which shows the state of the pump control apparatus at the time of carrying out compound operation of an arm and a bucket. It is another form (the 1) of the hydraulic circuit figure of the pump control apparatus mounted in the construction machine which concerns on this invention. It is another form (the 2) of the hydraulic circuit figure of the pump control apparatus mounted in the construction machine which concerns on this invention. It is another form (the 3) of the hydraulic circuit figure of the pump control apparatus mounted in the construction machine which concerns on this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Hydraulic excavator 2 ... Lower traveling body 3 ... Upper turning body 4 ... Boom 5 ... Arm 6 ... Bucket 7 ... Boom cylinder 8 ... Arm cylinder 9 ... Bucket cylinder 10L, 10R ... Hydraulic pump 11L ... Travel motor switching valve 11R ... Travel straight valve 12L ... Turning motor switching valve 12R ... Travel motor switching valve 13L ... Second speed boom Switching valve 13R ... First speed boom switching valve 14 ... Bucket switching valve 15L ... First speed arm switching valve 15R ... Second speed arm switching valve 20L, 20R ... Negative control throttle 22. ..Pressure oil tank 23 ... Restriction 30L, 30R ... Center bypass pipe 32L, 32R ... Control pressure pipe 40L, 40R ... Regulator for hydraulic pump 41 ... Tilt actuators 42L, 42R ... Traveling hydraulic motor 44 ... Turning hydraulic motor 50 ... Arm operating lever 51 ... Boom operating lever 52 ... Control pump 53L, 53R ... Total horsepower control unit 54 ... Main controller 55 ... Electromagnetic proportional valve 56 ... Bucket operation lever 57 ... Electromagnetic proportional valve 58 ... Electromagnetic proportional valve 59 ... Switching valve 60 ... -Spool mechanism 61 ... Negative control unit 65 ... Shuttle valve 100, 200 ... Pump control device S1-S8 ... Pressure sensor

Claims (4)

A first operation mode in which only the first arm body is operated by pressure oil discharged from the first hydraulic pump and the second hydraulic pump, or the first arm body is moved by pressure oil discharged from the first and second hydraulic pumps. A construction machine having a second operation mode of operating the second arm body with pressure oil discharged from the second hydraulic pump while operating;
Absorption horsepower reduction that reduces the absorption horsepower of the second hydraulic pump when the first and second hydraulic pumps perform full horsepower control so as not to exceed the horsepower output by the drive source in the second operation mode. Means,
In the second operation mode, when the total horsepower control is performed by the first and second hydraulic pumps so as not to exceed the horsepower output by the drive source, the absorption horsepower increase that increases the absorption horsepower of the first hydraulic pump Means,
A construction machine comprising: The increase in the absorption horsepower by the absorption horsepower increase means is equal to or less than the decrease in the absorption horsepower by the absorption horsepower reduction means.
The construction machine according to claim 1. In the second operation mode, the absorption horsepower reducing means converts the absorption horsepower of the second hydraulic pump into a pressure oil amount necessary for the operation of the second arm body and a pressure oil amount for joining the first arm body. Set according to
The construction machine according to claim 1 or 2, characterized in that. The absorption horsepower reduction means reduces the absorption horsepower by a predetermined amount with respect to the maximum discharge amount of the second hydraulic pump in the total horsepower control, and the reduced absorption horsepower is necessary for the operation of the second arm body. Setting the absorption horsepower of the second hydraulic pump so as to gradually increase toward the maximum discharge amount of the second hydraulic pump according to an increase in the amount of pressure oil;
The construction machine according to any one of claims 1 to 3, wherein