JP5855496B2 - Construction machinery - Google Patents

Description

  The present invention relates to a construction machine including two pumps that are operated by output torque of an engine.

  Conventionally, in a construction machine equipped with two pumps, in the boom raising operation, the pressure oil from the first and second pumps is merged and supplied to the boom cylinder, and the arm cylinder is connected to the second pump side. A technique for controlling a regulator so as to reduce a flow rate difference between a first pump and a second pump according to the detected arm operation amount is detected (for example, Patent Document 1). reference).

JP 2005-083427 JP

  By the way, at the time of horizontal pulling work involving simultaneous operation of arm closing operation and boom raising operation, the vertical velocity vector increases vertically due to the weight of the arm and bucket, particularly at the start of the work, so that the bucket toe tends to pierce the ground. . In order to prevent this, a boom raising speed is required at the start of the leveling operation. On the other hand, the arm closing circuit normally incorporates a regeneration circuit that returns cylinder return oil due to its own weight drop to the supply side, so oil from the pump to the arm from the start of horizontal pulling work to the vicinity of the arm becomes vertical. The supply amount may be small.

  In this respect, the technique described in the above-mentioned Patent Document 1 reduces the flow rate difference between the two pumps as the difference in the arm closing operation amount with respect to the boom raising operation amount decreases. The effect cannot be obtained at the start, and the operability may be deteriorated.

  Then, an object of this invention is to provide the construction machine which can improve the operativity of combined operation of boom raising and arm closing.

In order to achieve the above object, according to one aspect of the present invention, an engine,
Connected to said engine, a first and a second pump which is operated by the output torque of the engine,
An arm cylinder driven by at least oil discharged by the first pump;
A regeneration circuit for returning the return oil of the arm cylinder to the supply side;
A boom cylinder driven by at least oil discharged by the second pump;
Means for detecting an operation amount of an operation member for operating the arm;
Means for detecting an operation amount of an operation member for operating the boom;
With a controller,
The controller supplies oil from the regeneration circuit to the supply side of the arm cylinder during a predetermined combined operation of an arm closing operation and a boom raising operation, and a discharge oil amount of the second pump The construction is characterized in that at least one of the discharge oil amount of the first pump and the discharge oil amount of the second pump is changed so as to be relatively larger than the discharge oil amount by a predetermined amount. A machine is provided.

  ADVANTAGE OF THE INVENTION According to this invention, the construction machine which can improve the operativity of combined operation of boom raising and arm closing is obtained.

It is a figure which shows the structural example of the construction machine 1 which concerns on this invention. 1 is a circuit diagram showing a hydraulic control system 60 according to one embodiment of the present invention. FIG. It is a flowchart which shows an example of the main processes performed by the main controller 54 of a present Example. FIG. 4 is a timing chart showing a relationship between a boom raising operation, an arm closing operation, and a flow rate difference with respect to a discharge flow rate of the hydraulic pumps 10L and 10R related to the process shown in FIG. It is a figure showing typically the state of construction machine 1 at the time of leveling work. It is a characteristic view showing the relationship between the secondary pressure of the electromagnetic proportional valve 57A and the absorption torque of the hydraulic pump 10L. It is a characteristic view which shows an example of the relationship between the discharge pressure and discharge flow rate of the hydraulic pump 10L, and the relationship between the engine speed N and the output torque Te. 7 is a flowchart illustrating an example of main processing executed by a main controller 54 according to the second embodiment.

  The best mode for carrying out the present invention will be described below with reference to the drawings.

  FIG. 1 is a diagram illustrating a configuration example of a construction machine 1 according to the present invention. In FIG. 1, a construction machine 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. The drilling attachment may be another attachment such as a breaker or a crusher.

  FIG. 2 is a diagram illustrating an example of a hydraulic circuit diagram of the hydraulic pump control device 100 mounted on the construction machine 1. In FIG. 2, for convenience, the engine 70 is shown in two places, but there is only one engine 70.

  The hydraulic pump control device 100 includes a center bypass pipe line 30L that connects the switching valves 11L, 12L, 13L, and 15L from the two hydraulic pumps 10L, 10R driven by the engine 70, or the switching valves 11R, 12R, 13R, Pressure oil is circulated to the tank 22 through a center bypass pipe line 30R that communicates 14R and 15R. The hydraulic pumps 10L and 10R are variable displacement inclined plate piston pumps, and the discharge amount (cc / rev) per rotation is variable. The discharge pressures P1, P2 of the hydraulic pumps 10L, 10R are detected by pressure sensors 28L, 28R. Output signals from the pressure sensors 28L and 28R are supplied to the main controller 54.

  The switching valves 11L, 12L, 13L, and 15L and the switching valves 11R, 12R, 13R, 14R, and 15R are all open center types. That is, the switching valves 11L, 12L, 13L, and 15L and the switching valves 11R, 12R, 13R, 14R, and 15R are normally hydraulically connected by connecting their bleed-off passages to the center bypass conduits 30L and 30R. The discharge sides of the pumps 10L and 10R are connected to the tank 22.

  The switching valve 11L 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 traveling hydraulic motor 42L.

  Further, the switching valves 13L and 13R supply pressure oil discharged from the hydraulic pumps 10L and 10R to the boom cylinder 7 and flow the pressure oil to discharge the pressure oil in the boom cylinder 7 to the tank 22, respectively. The switching valve 13R is a spool valve that operates when the boom operating lever of the operating device 26 is operated (hereinafter referred to as “first speed boom switching valve 13R”), and the switching valve 13L. Is 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 is operated at a predetermined operation amount or more.

  The switching valve 14 </ b> R 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 9 to the tank 22.

  Further, the switching valves 15L and 15R supply pressure oil discharged from the hydraulic pumps 10L and 10R to the arm cylinder 8, respectively, and flow the pressure oil in order to discharge the pressure oil in the arm cylinder 8 to the tank 22. The switching valve 15L is a spool valve that operates when the arm operating lever of the operating device 26 is operated (hereinafter referred to as “first speed arm switching valve 15L”), and the switching valve 15R. Is 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 is operated at a predetermined operation amount or more. The first speed arm switching valve 15L incorporates a regeneration circuit (not shown) for returning the cylinder return oil to the supply side.

  The operation device 26 is an operation device for operating the turning hydraulic motor 44, the traveling hydraulic motors 42L and 42R, the boom 4, the arm 5, and the bucket 6, and includes various levers and pedals (arm operation lever, boom operation). Lever, bucket operation lever, turning operation lever, travel pedal (right), travel pedal (left)). Electric signals representing the operation amounts of various levers and pedals in the operation device 26 are supplied to the main controller 54. The method for detecting the amount of operation of various levers and pedals by the user may be a method for detecting the pilot pressure with a pressure sensor, or a method for detecting the lever angle.

  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 on the most downstream side and the tank 22 to restrict the flow of the pressure oil discharged by the hydraulic pumps 10L and 10R. This is a pressure oil pipe for generating a control pressure for the negative control system (hereinafter referred to as “negative control pressure”) upstream of the negative control throttles 20L and 20R. The negative control pressure is detected by negative control pressure sensors 27L and 27R. Output signals of the negative control pressure sensors 27L and 27R are supplied to the main controller 54.

  In the configuration shown in FIG. 2, the negative control pressure upstream of the negative control throttles 20L, 20R, the discharge pressures P1, P2, etc. are detected by the pressure sensors 27L, 27R, 28L, 28R, and the detected negative control pressures, discharge pressures P1, P2, etc. The main controller 54 obtains a target value of the discharge flow rate, and drives the electromagnetic proportional valves 57A and 55A to displace the spool valves 600L and 600R so as to obtain the target value of the discharge flow rate, thereby tilting actuators 41L and 41R. To control. At this time, typically, the main controller 54 decreases the discharge amount of the hydraulic pumps 10L and 10R as the detected negative control pressure increases, and the discharge flow rate of the hydraulic pumps 10L and 10R decreases as the detected negative control pressure decreases. Increase the target value. Further, the main controller 54 calculates a discharge flow rate (horsepower control target value) commensurate with an arbitrary set torque based on the discharge pressures P1 and P2, and is calculated based on the horsepower control target value and the negative control pressure as described above. The smaller one of the target values of the discharged flow rate is selected as the final target value.

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

  At this time, the main controller 54 displaces the spool valves 600L and 600R to the first position and drives the tilt actuators 41L and 41R to reduce the discharge amounts of the hydraulic pumps 10L and 10R. Pressure loss (pumping loss) when passing through the bypass pipes 30L and 30R is suppressed.

  On the other hand, when any hydraulic actuator in the construction machine 1 is used, the pressure oil discharged from the hydraulic pumps 10L, 10R flows into the hydraulic actuator via the switching valve corresponding to the hydraulic actuator, and the negative control throttle 20L, The amount up to 20R is reduced or eliminated, and the negative control pressure generated upstream of the negative control throttles 20L and 20R is reduced.

  At this time, the main controller 54 increases the discharge amount of the hydraulic pumps 10L and 10R, circulates sufficient pressure oil to each hydraulic actuator, and ensures the driving of each actuator.

  With the above-described configuration, the hydraulic 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. In the case of operating various hydraulic actuators while suppressing the pumping loss), necessary and sufficient pressure oil can be supplied to the various hydraulic actuators from the hydraulic pumps 10L and 10R.

  Next, a characteristic control method by the main controller 54 of the present embodiment (first embodiment) will be described.

  FIG. 3 is a flowchart showing an example of main processing executed by the main controller 54 of this embodiment. The processing routine shown in FIG. 3 may be started in a no-operation state where no operation is performed, and may be repeatedly executed at predetermined intervals.

  In step 300, based on the signal from the operating device 26, it is determined whether a predetermined combined operation of the arm closing operation and the boom raising operation has been detected. The predetermined composite operation is a composite operation for horizontal pulling work (see FIG. 5). In this case, the main controller 54 may detect an operation in which the operation amount of the arm closing operation and the operation amount of the boom raising operation increase from a state where the operation amount is zero to substantially the same operation amount as a predetermined composite operation. Good. At this time, the boom raising operation to be detected may be a boom raising operation in which the boom operation lever is operated with a predetermined operation amount or more. That is, the boom raising operation to be detected may be a second speed boom raising operation. If a predetermined composite operation is detected, the process proceeds to step 302. If a predetermined composite operation is not detected, a waiting state for the predetermined composite operation is entered.

  In step 302, a flow rate difference is given to the discharge flow rates of the hydraulic pumps 10L and 10R. The application of the flow rate difference is such that the amount of oil discharged from the hydraulic pump 10R and the amount of oil discharged from the hydraulic pump 10R are such that the amount of oil discharged from the hydraulic pump 10R is relatively larger than the amount of oil discharged from the hydraulic pump 10L by a predetermined amount α. It may be realized by changing at least one of them. For example, when the final target value of the discharge oil amount of the hydraulic pump 10R determined as described above is Qr and the final target value of the discharge oil amount of the hydraulic pump 10L determined as described above is Ql, the hydraulic pump 10R. The final target value of the discharge oil amount may be corrected to Qr + γ, and the final target value of the discharge oil amount of the hydraulic pump 10L may be corrected to Ql−ζ. However, (Qr + γ) − (Ql−ζ) = α. Therefore, γ + ζ = α when Qr = Ql, ζ = α when γ = 0, and γ = α when ζ = 0. The corrected final target value is determined within a range that does not exceed a predetermined upper limit value in order to prevent overload of the engine 70. In this case, the main controller 54 controls the tilt actuators 41L and 41R by driving the electromagnetic proportional valves 57A and 55A and displacing the spool valves 600L and 600R so that the final target values after correction are realized. .

  In step 304, based on the signal from the operation device 26, it is determined whether or not the boom raising operation has started to return to the neutral side. That is, it is determined whether or not the boom raising operation amount has started to be reduced. This determination may be realized by determining whether or not the boom raising operation amount has been reduced below a predetermined value. When the boom raising operation is started to return to the neutral side, the process proceeds to step 306. On the other hand, when the boom raising operation has not started to return to the neutral side, that is, when the boom raising operation in the first half of the horizontal pulling operation is continued (for example, when the boom raising operation amount is maintained at a predetermined value or more), Returning to step 302, the application of the flow rate difference to the discharge flow rates of the hydraulic pumps 10L and 10R is maintained.

  In this way, when a predetermined combined operation for the horizontal pulling operation is detected, a predetermined flow rate difference α is given to the discharge flow rates of the hydraulic pumps 10L and 10R. It is maintained until the boom raising operation starts to return to the neutral side after the middle stage.

  In step 306, the flow rate difference applied in step 302 is eliminated. That is, the original control state is restored. Specifically, when the final target value of the discharge oil amount of the hydraulic pump 10R determined as described above is Qr, and the final target value of the discharge oil amount of the hydraulic pump 10L determined as described above is Ql, The main controller 54 controls the tilt actuators 41L and 41R by driving the electromagnetic proportional valves 57A and 55A to displace the spool valves 600L and 600R so that the final target values Qr and Ql are realized.

  FIG. 4 is a timing chart showing the relationship between the boom raising operation, the arm closing operation, and the flow rate difference with respect to the discharge flow rates of the hydraulic pumps 10L and 10R related to the processing shown in FIG. In FIG. 4, in order from the top, the waveform of the operation amount of the boom raising operation, the waveform of the operation amount of the turning operation, and the flow rate difference given to the discharge flow rates of the hydraulic pumps 10L and 10R (= discharge of the hydraulic pump 10R). A waveform of a flow rate obtained by subtracting the discharge flow rate of the hydraulic pump 10L from the flow rate is shown. FIG. 5 is a diagram schematically showing the state of the construction machine 1 during the horizontal pulling operation.

  In the example shown in FIG. 4, a predetermined composite operation for the horizontal pulling operation is started at time t1. In the example shown in FIG. 4, the operation amount of the boom raising operation and the operation amount of the arm closing operation are increased to substantially the same operation amount substantially simultaneously. Accordingly, the determination at step 300 in FIG. 3 is affirmative, and the process at step 302 in FIG. 3 is started. As a result, the flow rate difference between the hydraulic pumps 10L and 10R starts to occur at time t1. In the example shown in FIG. 4, before the time t1, that is, before the boom raising operation is started, the flow rate difference between the hydraulic pumps 10L and 10R is zero. The flow rate difference between the hydraulic pumps 10L and 10R increases from the time t1 toward the predetermined flow rate difference α.

  Thereafter, at time t2, the boom raising operation is started to return to the neutral side. Accordingly, the determination at step 304 in FIG. 3 is affirmative, and the process at step 306 in FIG. 3 is executed. As a result, the flow rate difference between the hydraulic pumps 10L and 10R starts to be reduced from time t2. In the example shown in FIG. 4, the flow rate difference between the hydraulic pumps 10L and 10R starts to be reduced to zero before the time t1, that is, before the boom raising operation is started, at time t3. The flow rate difference becomes zero.

  Here, the combination of the waveform of the operation amount of the boom raising operation and the waveform of the operation amount of the arm closing operation shown in FIG. 4 corresponds to the operation when performing the horizontal pulling operation (see FIG. 5) in the hydraulic excavator. In the horizontal pulling work, as shown in FIG. 5, the speed vector F downward in the vertical direction is particularly large due to the weight of the arm 5 and the bucket 6 at the start of the work, so that the toe of the bucket 6 is likely to pierce the ground GL. In order to prevent this, a boom raising speed is required at the start of the leveling operation. On the other hand, since the arm closing circuit normally incorporates a regeneration circuit (not shown) for returning the cylinder return oil due to its own weight drop to the supply side, the arm 5 is perpendicular to the ground GL from the start of the horizontal pulling operation. Until near, the amount of oil supplied from the hydraulic pump 10L to the arm cylinder 8 may be small.

  In this regard, according to this embodiment, as described above, when the start of a predetermined combined operation for the horizontal pulling operation is detected, the flow rate difference α is given to the discharge flow rates of the hydraulic pumps 10L and 10R. Therefore, a larger flow rate is supplied to the boom cylinder 7 than when the flow rate difference α is not applied. Accordingly, the boom 4 is easily raised, and it becomes easy to prevent the tip of the bucket 6 from being stuck into the ground GL by its own weight, and the operability of the boom 4 is improved. On the other hand, compared to the case where the flow rate difference α is not applied, the discharge flow rate of the hydraulic pump 10L itself is reduced from the start of the horizontal pulling operation to the vicinity of the arm 5 being vertical, so the hydraulic pump 10L to the arm cylinder 8 The amount of oil supplied from is reduced. However, a necessary amount of oil is supplied from a regeneration circuit (not shown) to the arm cylinder 8. In this way, the oil from the hydraulic pumps 10L and 10R can be supplied to the arm cylinder 8 and the boom cylinder 7 at an efficient distribution ratio from the start of the horizontal pulling operation to the vicinity of the arm 5 being vertical. At the same time, the operability at the start of the leveling work (particularly from the start of the leveling work to the vicinity of the arm 5 being vertical) is improved.

  In the present embodiment, as described above, the flow rate difference α is reduced toward zero when the arm 5 becomes vertical after the horizontal pulling operation is started, but the arm 5 is vertical after the horizontal pulling operation is started. Conversely, the flow rate difference β may be applied so that the discharge oil amount of the hydraulic pump 10L is relatively larger than the discharge oil amount of the hydraulic pump 10R by a predetermined amount β. This is because the closing speed of the arm 5 becomes more necessary after the middle stage of the horizontal pulling work (after reaching the vicinity where the arm 5 becomes vertical).

  Further, in the present embodiment, as described above, when the boom raising operation is started to return to the neutral side, the flow rate difference α is reduced toward zero, but as shown by a one-dot chain line in FIG. The flow rate difference α may be reduced toward zero with a relatively gentle slope after a predetermined time Δt has elapsed since the start of the leveling operation (for example, time t1).

  Further, even in the combined operation of the boom raising operation and the arm closing operation, it is not preferable to prevent the tip of the bucket 6 from being easily stuck into the ground GL during excavation. In this respect, in this embodiment, as described above, the flow rate difference α is limited to the horizontal pulling operation of the combined operation of the boom raising operation and the arm closing operation. Sex (workability) is not hindered. It should be noted that the excavation time is equivalent to the latter half of the leveling work (after time t3 in FIG. 4). Therefore, in this case, since the boom raising operation amount is small with respect to the arm closing operation amount (because it is approximately half), the determination in step 300 in FIG. 3 is negative and the flow rate difference α is not formed. In this way, in this embodiment, it is possible to realize an optimum flow rate difference between the leveling work and the excavation work.

  Next, another embodiment (Example 2) will be described. In the following other embodiment (embodiment 2), only the control method is mainly different from the above embodiment (embodiment 1), and the components themselves may be the same. Will be described with the same reference numerals as in the first embodiment. In the following, the configuration unique to the second embodiment will be mainly described, and other configurations may be the same as those of the first embodiment.

  In the second embodiment, the main controller 54 controls the hydraulic pumps 10L and 10R in a plurality of modes. In this example, the plurality of modes include a high horsepower mode (H mode), a standard mode (S mode), and an energy saving mode (L mode). Note that switching between these modes may be realized manually. However, even in this case, as will be described later, the main controller 54 automatically executes mode switching under certain conditions.

  FIG. 6 is a characteristic diagram showing an example of the relationship between the secondary pressure of the electromagnetic proportional valve 57A and the absorption torque of the hydraulic pump 10L. The relationship between the secondary pressure of the electromagnetic proportional valve 55A and the absorption torque of the hydraulic pump 10R may be the same. The relationship between the secondary pressure of the electromagnetic proportional valve 57A and the absorption torque of the hydraulic pump 10L may be an inversely proportional relationship as shown in FIG. In the example shown in FIG. 6, the absorption torque is maintained at the maximum value Tmax when the secondary pressure of the electromagnetic proportional valve 57A is Pr1, and when the secondary pressure of the electromagnetic proportional valve 57A exceeds Pr1, the absorption torque is inversely proportional. Decreases from the maximum value Tmax to the minimum value Tmin. The absorption torque corresponds to the torque (consumption torque) consumed when the hydraulic pump 10L is driven.

  In the H mode, the secondary pressure of the electromagnetic proportional valve 57A is set to Pr1. As a result, the discharge flow rate of the hydraulic pump 10L increases and the actual absorption torque also increases. In the L mode, the secondary pressure of the electromagnetic proportional valve 57A is set to Pr2. Thereby, the discharge flow rate of the hydraulic pump 10L is reduced, and the actual absorption torque is also reduced. In the S mode, the secondary pressure of the electromagnetic proportional valve 57A is set to a value (not shown) between Pr1 and Pr2.

  FIG. 7 is a characteristic diagram showing an example of the relationship between the discharge pressure and the discharge flow rate of the hydraulic pump 10L and the relationship between the engine speed N and the output torque Te. The same applies to the hydraulic pump 10R.

The H mode, as indicated by a solid line H in the figure, until the discharge pressure of the hydraulic pump 10L reaches the inclined plate that starts to tilt (tilt starting pressure) P _AH of the hydraulic pump 10L, the pump discharge quantity Q is constant in (maximum discharge amount _{Q max),} the discharge pressure of the hydraulic pump 10L decreases with horsepower constant curve thereafter reaching _{P AH.} Incidentally, until the discharge pressure reaches P _AH, the discharge pressure of the hydraulic pump 10L is controlled as a state reached P _AH. On the other hand, the pump characteristic in the L mode is constant (maximum discharge amount Q) until the discharge pressure reaches (tilting start pressure) P _AL (<P _AH ), as indicated by a solid line L in the figure. _max ), and after the discharge pressure reaches _PAL , it decreases according to a constant horsepower curve. Further, the absorption torque TH, TL, the discharge pressure of the hydraulic pump 10L increases _{P AH,} in each until a _{P AL} straight, discharge pressure _{P AH,} is subsequently reaches a _{P AL} constant _{(T max)} It becomes. Note that the discharge pressure of the hydraulic pump 10L varies depending on the reaction force generated by work such as excavation.

  Thus, in the H mode, the absorption torque is larger than in the L mode, and high output is possible. On the other hand, in the L mode, the absorption torque is smaller than in the H mode, and energy saving can be realized. The S mode is between the H mode and the L mode, and an intermediate (standard) characteristic can be realized.

  FIG. 8 is a flowchart illustrating an example of main processing executed by the main controller 54 according to the second embodiment. The processing routine shown in FIG. 8 may be started in a state where the boom raising operation is not performed (typically, a no-operation state where no other operation is performed) and may be repeatedly executed at predetermined intervals.

  In step 800, as in step 300 of FIG. 3 described above, based on the signal from the operating device 26, it is determined whether or not a predetermined combined operation of the arm closing operation and the boom raising operation has been detected. If a predetermined composite operation is detected, the process proceeds to step 802. If a predetermined composite operation is not detected, a waiting state for the predetermined composite operation is entered.

  In step 802, the mode is changed so that a flow rate difference is given to the discharge flow rates of the hydraulic pumps 10L and 10R. For example, when both the hydraulic pumps 10L and 10R are operating in the S mode, the hydraulic pump 10R may be changed from the S mode to the H mode. Instead of or in addition to this, the hydraulic pump 10L may be changed from the S mode to the L mode. When both the hydraulic pumps 10L and 10R are operating in the H mode, the hydraulic pump 10L may be changed from the H mode to the S mode or the L mode. Further, when both the hydraulic pumps 10L and 10R are operating in the L mode, the hydraulic pump 10R may be changed from the L mode to the S mode or the H mode.

  In step 804, based on the signal from the operating device 26, it is determined whether or not the boom raising operation has started to return to the neutral side. That is, it is determined whether or not the boom raising operation amount has started to be reduced. This determination may be realized by determining whether or not the boom raising operation amount has been reduced below a predetermined value. When the boom raising operation is started to return to the neutral side, the process proceeds to step 806. On the other hand, when the boom raising operation has not started to return to the neutral side, that is, when the boom raising operation in the first half of the horizontal pulling operation is continued (for example, when the boom raising operation amount is maintained at a predetermined value or more), Returning to step 802, the changed modes of the hydraulic pumps 10L, 10R are maintained.

  In this way, when a predetermined combined operation for the horizontal pulling operation is detected, the mode is changed so that a predetermined flow rate difference is given to the discharge flow rates of the hydraulic pumps 10L and 10R. The mode is maintained until the boom raising operation starts to return to the neutral side after the middle stage of the horizontal pulling operation.

  In step 806, the mode changed in step 802 is returned to the original mode. That is, the original control state is restored, and the flow rate difference is reduced (in this example, the flow rate difference becomes zero).

  In the case of the second embodiment, the same effects as those of the first embodiment can be obtained. In particular, according to the second embodiment, for example, when operating in the L mode at normal times, the H mode or the S mode is realized only when necessary while saving energy in the L mode, and the first embodiment described above. The same effect can be obtained.

  In the second embodiment, the mode can be switched between the three modes of the L mode, the S mode, and the H mode. However, a configuration in which the mode can be switched between the two modes may be used. It may be possible to switch between the two.

  The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the above-described embodiments, and various modifications and substitutions can be made to the above-described embodiments without departing from the scope of the present invention. Can be added.

  For example, in the above description, the hydraulic circuit having the specific configuration illustrated in FIG. 2 is disclosed, but the configuration of the hydraulic circuit is various. For example, a part of the hydraulic actuator may be realized by a hydraulic pump driven by an electric motor. Further, a hydraulic circuit that realizes a control method other than negative control (for example, positive control, load sensing, etc.) may be used.

DESCRIPTION OF SYMBOLS 1 Construction machine 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, 11R Switching valve 12L, 12R Switching valve 13L, 13R Switching valve 14R Switching valve 15L , 15R switching valve 20L, 20R negative control throttle 22 tank 26 operating device 27L, 27R negative control pressure sensor 28L, 28R pressure sensor 30L, 30R center bypass conduit 41L, 41R tilting actuator 42L, 42R traveling hydraulic motor 44 turning hydraulic motor 54 Main controller 55A, 57A Proportional solenoid valve 70 Engine 100 Hydraulic pump controller 600L, 600R Spool valve

Claims (8)

Engine,
Connected to said engine, a first and a second pump which is operated by the output torque of the engine,
An arm cylinder driven by at least oil discharged by the first pump;
A regeneration circuit for returning the return oil of the arm cylinder to the supply side;
A boom cylinder driven by at least oil discharged by the second pump;
Means for detecting an operation amount of an operation member for operating the arm;
Means for detecting an operation amount of an operation member for operating the boom;
With a controller,
The controller supplies oil from the regeneration circuit to the supply side of the arm cylinder during a predetermined combined operation of an arm closing operation and a boom raising operation, and a discharge oil amount of the second pump The construction is characterized in that at least one of the discharge oil amount of the first pump and the discharge oil amount of the second pump is changed so as to be relatively larger than the discharge oil amount by a predetermined amount. machine.   When the controller detects an operation of returning the boom raising operation to the neutral side after detecting the predetermined composite operation, the controller discharges the second pump discharge oil amount and the second pump oil generated by the change in the discharge oil amount. The construction machine according to claim 1, wherein at least one of the discharge oil amount of the first pump and the discharge oil amount of the second pump is changed so that a difference from the discharge oil amount of the pump is reduced. . Engine,
First and second pumps connected to the engine and operated by output torque of the engine;
An arm cylinder driven by at least oil discharged by the first pump;
A boom cylinder driven by at least oil discharged by the second pump;
Means for detecting an operation amount of an operation member for operating the arm;
Means for detecting an operation amount of an operation member for operating the boom;
With a controller,
When the controller detects a predetermined combined operation of an arm closing operation and a boom raising operation, the discharge oil amount of the second pump is relatively larger than the discharge oil amount of the first pump by a predetermined amount. And changing at least one of the discharge oil amount of the first pump and the discharge oil amount of the second pump,
The controller detects a difference between a discharge oil amount of the first pump and a discharge oil amount of the second pump caused by a change in the discharge oil amount when a predetermined time has elapsed after detecting the predetermined composite operation. so it reduces, wherein altering the at least one of the discharge oil amount and the discharge oil amount of the second pump of the first pump, construction machinery. Engine,
First and second pumps connected to the engine and operated by output torque of the engine;
An arm cylinder driven by at least oil discharged by the first pump;
A boom cylinder driven by at least oil discharged by the second pump;
Means for detecting an operation amount of an operation member for operating the arm;
Means for detecting an operation amount of an operation member for operating the boom;
With a controller,
When the controller detects a predetermined combined operation of an arm closing operation and a boom raising operation, the discharge oil amount of the second pump is relatively larger than the discharge oil amount of the first pump by a predetermined amount. And changing at least one of the discharge oil amount of the first pump and the discharge oil amount of the second pump,
The controller independently controls each of the first and second pumps in one mode selected from among a plurality of modes, and the plurality of modes correspond to the first mode and the same output torque of the engine. A second mode having a higher absorption torque than the first mode,
When the controller detects the predetermined combined operation, the controller changes the mode of the second pump from the first mode to the second mode, and changes the mode of the first pump from the second mode to the second mode. changing the first mode, and performs at least one of the, construction machinery.   The construction machine according to claim 4, wherein the controller returns the changed mode to the original mode when detecting an operation for returning the boom raising operation to the neutral side after detecting the predetermined composite operation.   5. The construction machine according to claim 4, wherein the controller returns the changed mode to the original mode when a predetermined time has elapsed after detecting the predetermined composite operation.   The construction machine according to any one of claims 1 to 6, wherein the predetermined complex operation is a complex operation for horizontal pulling work. Engine,
First and second pumps connected to the engine and operated by output torque of the engine;
An arm cylinder driven by at least oil discharged by the first pump;
A boom cylinder driven by at least oil discharged by the second pump;
Means for detecting an operation amount of an operation member for operating the arm;
Means for detecting an operation amount of an operation member for operating the boom;
With a controller,
When the controller detects a predetermined combined operation of an arm closing operation and a boom raising operation, the discharge oil amount of the second pump is relatively larger than the discharge oil amount of the first pump by a predetermined amount. And changing at least one of the discharge oil amount of the first pump and the discharge oil amount of the second pump,
Wherein the controller, the operation amount is zero and the state, an operation of the operation amount of the arm close operation to substantially the same operation amount and the operation amount of the boom raising operation is increased, and detects as the predetermined combined operation , construction machinery.

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