JP2018155065A - Hydraulic control device of construction machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform whole horsepower control, and to supply a required flow rate to an option actuator irrespective of a difference in loads between the option actuator and an attachment actuator at the time of composite driving of the option actuator and the attachment actuator.SOLUTION: An option actuator 9, which guides a discharge pressure of a second hydraulic pump 10b to a first regulator 28a and guides a discharge pressure of a first hydraulic pump 10a to a second regulator 28b to enable whole horsepower control, and drives an option device 3, includes: a shut-off device including a switching valve 43 which is driven by pressure oil discharged from the second hydraulic pump 10b and shuts off the discharge pressure of the first hydraulic pump 10a guided to the second regulator 28b; and a controller 40 which outputs a signal for shutting off the discharge pressure of the first hydraulic pump 10a guided to the second regulator 28b to the shut-off device when the option device 3 is operated.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a hydraulic control device for a construction machine, such as a hydraulic excavator, which has a work attachment on which an optional device can be mounted at a tip portion and can control the total horsepower.

  In a construction machine such as a hydraulic excavator provided with a work attachment that operates so that the tip portion is displaced, an optional device may be mounted on the tip portion. For example, in a general hydraulic excavator, a boom that can be raised and lowered as a work attachment, an arm that is pivotably connected to the tip of the boom, and an arm that is pivotable in the vertical direction are connected to the tip of the arm. However, from the viewpoint of versatility, various optional devices may be mounted instead of the bucket. Optional equipment includes concrete vibrators, mowers, twin headers, harvesters, and breakers. Unlike the case of a bucket, these optional devices require a fixed flow rate (a constant flow rate) as a flow rate supplied to an optional actuator that drives the optional device.

  Further, in the above-described hydraulic excavator, when two or more hydraulic pumps are provided, a pump control device that performs torque control generally called total horsepower control is provided. For example, this total horsepower control leads the discharge pressures of both the first hydraulic pump and the second hydraulic pump to the regulators of two hydraulic pumps (hereinafter referred to as “first hydraulic pump” and “second hydraulic pump”), When the sum of the absorption torque of the first hydraulic pump and the absorption torque of the second hydraulic pump reaches the set maximum absorption torque, the first hydraulic pump and the second hydraulic pump will increase with respect to further increase in the discharge pressure of the hydraulic pump. Each regulator is controlled to reduce the displacement volume. As a result, when a plurality of actuators driven by pressure oil discharged from the first hydraulic pump and the second hydraulic pump are driven independently, the total horsepower allocated to the first hydraulic pump and the second hydraulic pump can be utilized. Therefore, the motor output can be effectively used.

  In a construction machine equipped with a pump control device that performs total horsepower control, when driving a plurality of actuators simultaneously, for example, an arm cylinder that is one of the attachment actuators that drives a work attachment and other actuators are combined. In this case, the pressure oil from the first hydraulic pump is supplied to the arm cylinder, and the pressure oil from the second hydraulic pump is supplied to the other actuators, regardless of the load of the arm cylinder and the other actuators. Pressure oil having an appropriate flow rate can be supplied to these actuators.

  However, when one of the actuators becomes a high load during the above-described combined drive, the discharge pressure of the hydraulic pump driving the high-load actuator rises, and accordingly, the first hydraulic pump and the second hydraulic pump The average discharge pressure of the hydraulic pump increases, the displacement of the hydraulic pump that supplies pressure oil to the other actuator decreases, and the drive speed of the other actuator decreases.

  In Patent Document 1, when it is detected that the discharge pressure of the hydraulic pump that drives the optional actuator has increased to the relief pressure when a plurality of actuators such as the optional actuator and the attachment actuator are combined, pressure oil is supplied to the optional actuator. Disclosed is a hydraulic control device for a work machine that prevents a decrease in the drive speed of an arm cylinder by lowering the discharge flow rate of the hydraulic pump that is supplied and increasing the discharge flow rate of the hydraulic pump that supplies pressure oil to the arm cylinder. ing.

JP2013-249849A

  By the way, in concrete vibrators, mowers, twin headers, harvesters, breakers, etc. that constitute optional equipment, unlike the case of the bucket as described above, a constant flow rate is always supplied to the optional actuator that drives the optional equipment. I need it. However, in the total horsepower control, when the option actuator and the attachment actuator are combined, the load pressure of the attachment actuator rises and the average discharge pressure of the first hydraulic pump and the second hydraulic pump rises. The flow rate may decrease and workability may deteriorate.

  As described above, the prior art disclosed in Patent Document 1 detects that the pressure of the hydraulic pump that supplies pressure oil to the option actuator reaches the relief pressure when the option actuator and the attachment actuator are combined. The flow rate supplied to the attachment actuator is ensured by lowering the discharge flow rate of the hydraulic pump that supplies pressure oil and increasing the discharge flow rate of the hydraulic pump that supplies pressure oil to the attachment. However, in the prior art of Patent Document 1, the discharge flow rate of the hydraulic pump that supplies pressure oil to the optional actuator is reduced even when the load pressure of the optional actuator does not reach the relief pressure but the load becomes high. In such a case, the required flow rate is not supplied to the optional actuator, and workability is reduced. In the prior art of Patent Document 1, no consideration is given to this point.

  In order to solve the above-described problems, an object of the present invention is to perform total horsepower control, and in the combined drive of the option actuator and the attachment actuator, the option actuator can be used regardless of the load difference between the option actuator and the attachment actuator. An object of the present invention is to provide a hydraulic control device for a construction machine that can supply a necessary flow rate.

  In order to achieve this object, the present invention provides a work attachment in which an optional device can be attached to a tip, an attachment actuator that drives the work attachment, an option actuator that drives the optional device, the attachment actuator, and A first hydraulic pump and a second hydraulic pump for supplying pressure oil for operating the optional actuator; an engine for driving the first hydraulic pump and the second hydraulic pump; and a displacement volume of the first hydraulic pump. A second regulator that controls displacement of the first regulator and the second hydraulic pump, an attachment operation device that operates the attachment actuator, and an option operation device that operates the option actuator, The discharge pressure of the second hydraulic pump is guided to the first regulator, the discharge pressure of the first hydraulic pump is guided to the second regulator, and the total horsepower of the first hydraulic pump and the second hydraulic pump is obtained. A mechanism for controlling the engine within a predetermined horsepower range, wherein the optional actuator is a hydraulic control device for a construction machine driven by pressure oil discharged from the second hydraulic pump, and the second regulator A shut-off device that shuts off the discharge pressure of the first hydraulic pump led to the first pressure pump and a signal that shuts off the discharge pressure of the first hydraulic pump led to the second regulator when the optional device is operated. And a controller for outputting to the apparatus.

  The hydraulic control device for a construction machine according to the present invention supplies the required flow rate to the option actuator and reduces the speed of the option actuator regardless of the load difference between the option actuator and the attachment actuator when the option actuator and the attachment actuator are combined. It is possible to prevent the deterioration of the workability of the work performed by the optional device by operating without causing it. Further, when the optional device is not operated, the engine horsepower can be efficiently used by the total horsepower control.

1 is a side view showing a hydraulic excavator cited as an example of a construction machine provided with a hydraulic control device according to a first embodiment of the present invention. FIG. 2 is a hydraulic circuit diagram showing a hydraulic control device according to the first embodiment of the present invention provided in the hydraulic excavator shown in FIG. 1. It is a block diagram which shows the structure of the controller with which 1st Embodiment was equipped, and the apparatus relevant to a controller. It is a flowchart which shows the process sequence in the controller shown in FIG. FIG. 5 is a diagram illustrating characteristics in the first embodiment, where (a) is a characteristic diagram illustrating a relationship between pump pressure and pump flow rate in total horsepower control, and (b) is a pump pressure in specific control performed by the controller of the present embodiment. And (c) is a characteristic diagram showing the relationship between the operation signal pressure output from the operating device and the pump flow rate. It is a hydraulic circuit diagram which shows the hydraulic control apparatus which concerns on 2nd Embodiment of this invention. It is a hydraulic circuit diagram which shows the hydraulic control apparatus which concerns on 3rd Embodiment of this invention.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of a construction machine hydraulic control apparatus according to the present invention will be described below with reference to the drawings.

[First Embodiment]
As shown in FIG. 1, the construction machine provided with the hydraulic control device according to the first embodiment is a hydraulic excavator, and a traveling body 1a and a revolving body 1b having a cab 1c provided on the traveling body 1a so as to be turnable. And a work attachment 2 attached to the base machine 1. The work attachment 2 includes a boom 4 attached to the swing body 1b of the base machine 1 so as to be raised and lowered, and an arm 5 attached to the tip portion of the boom 4 and connected to be rotatable in the vertical direction. . An optional device 3 is attached to the tip of the work attachment 2 in place of the bucket that is normally provided. The optional device 3 is constituted by, for example, a breaker.

  An extendable boom cylinder 6 is interposed between the revolving body 1b of the base machine 1 and the boom 4, and the boom cylinder 6 extends and contracts in response to the supply of pressure oil so that the boom 4 is raised. move. In addition, an arm cylinder 7 is provided between the boom 4 and the arm 5, and the arm cylinder 7 is extended by receiving the supply of pressure oil, thereby rotating the arm 5 in a pulling direction (a direction approaching the boom 4). Move. The boom cylinder 6 and the arm cylinder 7 constitute an attachment actuator.

  Further, a bucket cylinder 8 is interposed between the arm 5 and the optional device 3, and the bucket cylinder 8 extends by receiving supply of pressure oil, thereby pulling the optional device 3 in the pulling direction (approaching the arm 5). Rotate). The option device 3 is provided with an option actuator 9 shown in FIG. 2 for driving the option device 3. The option device 9 is driven by the operation of the option actuator 9 in response to the supply of pressure oil.

  As shown in FIG. 2, the hydraulic control apparatus according to the first embodiment includes a first hydraulic pump 10a, a second hydraulic pump 10b, a pilot pump 11, and these first hydraulic pump 10a and second hydraulic pump 10b. And an engine 12 that rotationally drives the pilot pump 11.

  In addition, a valve device 13 connected to the first hydraulic pump 10a and the second hydraulic pump 10b, a main relief valve 30 that holds the discharge pressure of the first hydraulic pump 10a and the discharge pressure of the second hydraulic pump 10b at a constant pressure, and It has.

  The valve device 13 has two valve groups, a valve group of flow control valves 14 to 16 and a valve group of flow control valves 17 to 20. The flow control valves 14 to 16 are located on the center bypass line 22a connected to the discharge passage 21a of the first hydraulic pump 10a, and the second hydraulic pump 10b is on the center bypass line 22b connected to the discharge passage 21b of the second hydraulic pump 10b. Is located.

  The flow control valve 14 of the valve device 13 is operated by the operation of the attachment operating device 23 that drives the bucket cylinder 8 that is an attachment actuator, and the flow control valve 20 is operated by the operation of the option operating device 24 that drives the optional device 3. Can be switched. The attachment operation device 23 and the option operation device 24 generate an operation signal pressure corresponding to the operation amount using the discharge pressure (temporary pressure) of the pilot pump 11 as a base pressure.

  Although not shown, the flow rate control valves 15, 16, 17 to 19 are also switched by the operation signal pressure from the pilot operation device including other attachment operation devices corresponding to the respective actuators.

  When the flow control valve 14 is switched, the pressure oil of the first hydraulic pump 10a is supplied to the bucket cylinder 8 through the pipe line 25a or the pipe line 25b. When the flow control valve 20 is switched, the pressure oil of the second hydraulic pump 10b is supplied to the option actuator 9 through the pipe line 26a or the pipe line 26b. When the flow control valves 15, 16, 17 to 19 are switched, the pressure oil of the first hydraulic pump 10a and the second hydraulic pump 10b is applied to the corresponding actuator, for example, the boom cylinder 6 and the arm cylinder 7 shown in FIG. Or, it is supplied to a turning motor and a traveling motor (not shown).

  The first hydraulic pump 10a and the second hydraulic pump 10b are swash plate type or oblique axis type variable displacement hydraulic pumps. The first hydraulic pump 10a is provided with a first regulator 28a for controlling the tilt of the swash plate or the oblique shaft of the first hydraulic pump 10a, that is, the displacement volume. Similarly, the second hydraulic pump 10b is provided with a second regulator 28b for controlling the displacement volume of the second hydraulic pump 10b.

  A pilot relief valve 31 that holds the discharge pressure of the pilot pump 11 at a constant pressure is connected to the discharge passage 29 of the pilot pump 11. The pilot pump 11 and the pilot relief valve 31 constitute a pilot hydraulic pressure source.

  The first hydraulic pump 10a and the second hydraulic pump 10b perform torque control called full horsepower control by the first regulator 28a and the second regulator 28b. The discharge pressure of the first hydraulic pump 10a is led to the first regulator 28a through the pipe line 32a, and the discharge pressure of the second hydraulic pump 10b is led through the pipe line 32b. Similarly, the discharge pressure of the first hydraulic pump 10a is led to the second regulator 28b through the pipe line 32a, and the discharge pressure of the second hydraulic pump 10b is led through the pipe line 32b. With this configuration, the total horsepower of the first hydraulic pump 10a and the second hydraulic pump 10b is controlled to be within a predetermined horsepower range of the engine 12.

The pump flow rate, that is, the discharge flow rate of the first hydraulic pump 10a and the second hydraulic pump 10b is controlled according to the horsepower diagram (PQ diagram) set as shown in FIG. The average discharge pressure PA led to the first regulator 28a and the second regulator 28b is
PA = (P1 + P2) (1)
[P1: Discharge pressure of the first hydraulic pump 10a, P2: Discharge pressure of the second hydraulic pump 10b]
At this time, the pump flow rates of the first hydraulic pump 10a and the second hydraulic pump 10b are Qp in FIG. 5 (a). That is, when the average discharge pressure of the first hydraulic pump 10a and the second hydraulic pump 10b increases, the flow rate is controlled so that the absorption horsepower of the pump does not exceed the engine horsepower.

  The torque control valve 50 guides the control pressure obtained by reducing the pressure oil from the pilot pump 11 to the first regulator 28a and the second regulator 28b. The horsepower characteristic is controlled as shown in FIG. 5A so that the pump capacity increases as the control pressure decreases.

  The first regulator 28a and the second regulator 28b perform positive control control for increasing the pump flow rate in accordance with an increase in the operation signal pressure generated by each pilot operating device including the attachment operating device 23 and the optional operating device 24. ing.

  When the flow control valves 14 to 16 on the center bypass line 22a are switched by a pilot operating device (not shown) including the attachment operating device 23, a pump is used according to the operation signal pressure generated from the corresponding pilot operating device. The flow rate control valve 33a is switched, and the pump flow rate of the first hydraulic pump 10a is controlled to increase as the operation signal pressure increases as shown in FIG. 5C. Further, when the flow control valves 17 to 20 on the center bypass line 22b are switched, the pump flow control valve 33b is switched according to the operation signal pressure generated from the corresponding pilot operation device, and FIG. As shown in (c), control is performed so that the pump flow rate of the second hydraulic pump 10b increases as the operation signal pressure increases.

  For the first regulator 28a and the second regulator 28b, a low-order selection is made between the pump flow rate obtained by full horsepower control and the pump flow rate obtained by positive control control for each of the first hydraulic pump 10a and the second hydraulic pump 10b. Thus, the displacement of the first hydraulic pump 10a and the second hydraulic pump 10b is controlled.

  As shown in FIG. 2, a detector that detects the operation amount of the option operation device 24, such as a pressure sensor 34a, and a detector that detects the operation amount of the attachment operation device 23, such as a pressure sensor 34b, are provided.

  In the first embodiment, the shut-off device that shuts off the discharge pressure of the first hydraulic pump 10a guided to the second regulator 28b and the first hydraulic pump 10a guided to the second regulator 28b when the optional device 3 is operated. And a controller 40 for outputting a signal for shutting off the discharge pressure to the shutoff device.

  The shut-off device includes a switching valve 43 including an electromagnetic valve that shuts off the discharge pressure of the first hydraulic pump 10a guided to the second regulator 28b, and the pressure sensor 34a described above. When the controller 40 determines that the operation of the optional device 3 is present based on the detection signal output from the pressure sensor 34a, the controller 40 shuts off the discharge pressure of the first hydraulic pump 10a that guides the switching valve 43 to the second regulator 28b. To operate.

  As shown in FIG. 3, the controller 40 includes a switching valve control unit 41 and a pump flow rate control unit 42. The pump flow rate control unit 42 includes a positive control calculation unit 42a, a horsepower control calculation unit 42b, and a pump capacity determination unit 42c. The positive control calculation unit 42a calculates the pump flow rate of the first hydraulic pump 10a and the pump flow rate of the second hydraulic pump 10b by positive control control based on the signals output from the pressure sensors 34a and 34b.

  The horsepower control calculation unit 42b is a signal output from the first pump discharge pressure sensor 44a that detects the discharge pressure of the first hydraulic pump 10a and the second pump discharge pressure sensor 44b that detects the discharge pressure of the second hydraulic pump 10b. Then, based on the horsepower of the engine 12, the pump flow rate of the first hydraulic pump 10a is calculated so as not to exceed the maximum absorption torque of the pump.

  The pump capacity determination unit 42c is a lower pump flow rate of the pump flow rate of the first hydraulic pump 10a output from the positive control calculation unit 42a and the pump flow rate of the first hydraulic pump 10a output from the horsepower control calculation unit 42b. Based on the above, the capacity of the first hydraulic pump is determined, and a corresponding control signal is output to the pump flow rate control valve 33a. Further, the capacity of the second hydraulic pump 10b is determined based on the pump flow rate of the second hydraulic pump 10b output from the positive control calculation unit 42a, and a corresponding control signal is output to the pump flow rate control valve 33b.

  The processing operation of the controller 40 provided in the first embodiment will be described below based on the flowchart of FIG. For example, it is assumed that a combined operation of an option actuator 9 that drives the option device 3 and a bucket cylinder 8 that is an attachment actuator is about to be performed.

[Step S1] It is determined whether the option operating device 24 has been operated based on a signal output from the pressure sensor 34a. When it is determined that the option operating device 24 has been operated, the process proceeds to step S2.

[Step S2] The switching valve control unit 41 of the controller 40 outputs a signal for switching the switching valve 43 to the lower position in FIG. Thereby, the discharge pressure of the first hydraulic pump 10a guided to the second regulator 28b is cut off, and the whole horsepower control is shifted to the individual horsepower control.

At this time, since only the discharge pressure of the second hydraulic pump 10b is guided to the second regulator 28b, the average discharge pressure Pa is
Pa = P2 / 2 (2)
It becomes.

  In normal full horsepower control, for example, when the optional device 3 and the work attachment 2 are combined and operated, if the discharge pressure of the first hydraulic pump 10a increases, the pump flow rate of the second hydraulic pump 10b is as shown in FIG. However, in the control in the first embodiment, the pump flow rate of the second hydraulic pump 10b is Q2 (> Qp) in FIG. 5B, so that the optional device 3 and the work attachment 2 are connected. When driven simultaneously, a required flow rate that is a constant flow rate can be supplied to the optional actuator 9 of the optional device 3.

  In the total horsepower control, the pump flow rate is controlled so that the total horsepower of the first hydraulic pump 10a and the second hydraulic pump 10b does not exceed the horsepower of the engine 12, so the pump flow rate of the second hydraulic pump 10b If the flow rate is controlled to be larger than the pump flow rate determined by the total horsepower control, the total horsepower of the first hydraulic pump 10a and the second hydraulic pump 10b may exceed the horsepower of the engine 12, which may cause lag down or engine stall.

Therefore, in the first embodiment, in the horsepower control calculation unit 42b of the controller 40, the difference between the horsepower (Xe) of the engine 12 and the absorption horsepower (Xp) of the second hydraulic pump 10b is defined as the absorption horsepower of the first hydraulic pump 10a. The total horsepower of the first hydraulic pump 10a and the second hydraulic pump 10b is prevented from exceeding the horsepower of the engine 12. The pump flow rate of the first hydraulic pump 10a is expressed by the following equation.
Q1 = (Xe−Xp) / P1 (3)
[Xp = P2 / Q2]
The pump flow rate Q1 obtained by this equation (3) is supplied to the bucket cylinder 8. After step S3, the process proceeds to step S4.

[Step S4] Based on the signal output from the pressure sensor 34a, it is determined whether the operation of the option operating device 24 is continued. When it is determined that the operation of the option operating device 24 is continued, the process returns to step S3. When it is determined that the operation of the option operating device 24 has stopped, the process proceeds to step S5.

[Step S5] The switching valve control unit 41 of the controller 40 outputs a signal for switching the switching valve 43 to OFF and switching to the upper position in FIG. As a result, the discharge pressure of the first hydraulic pump 10a is led to the second regulator 28b, and the normal full horsepower control is restored.

  In the first embodiment, as described above, when the optional actuator 9 and the bucket cylinder 8 that is an attachment actuator are combined and driven, the optional actuator 9 regardless of the load difference between the optional actuator 9 and the bucket cylinder 8. The required flow rate is supplied to the optional actuator 9 without causing a decrease in speed, so that the workability of the work performed by the optional device 3 can be prevented from being lowered. Further, when the optional device 3 is not operated, the horsepower of the engine 12 can be efficiently used by the total horsepower control.

[Second Embodiment]
As shown in FIG. 6, in the second embodiment, the shut-off device that shuts off the discharge pressure of the first hydraulic pump 10 a guided to the second regulator 28 b is used as the discharge pressure of the first hydraulic pump 10 a guided to the second regulator 28 b. Is constituted by a hydraulic switching valve 43b that shuts off the valve and an option operating device 24 that switches the switching valve 43b. Other configurations are the same as those of the first embodiment.

  In the second embodiment, when the option operating device 24 is operated to drive the option device 3, the operation signal pressure generated by the operation of the option operating device 24 is given to the control unit of the switching valve 43b. Thus, the switching valve 43b is switched to the lower position in FIG. As a result, similarly to the first embodiment described above, the discharge pressure of the first hydraulic pump 10a guided to the second regulator 28b is cut off, and the controller 40 switches from full horsepower control to individual horsepower control. The second embodiment configured as described above can achieve the same effect as the first embodiment.

[Third Embodiment]
As shown in FIG. 7, the third embodiment has a configuration including a changeover switch 60 that switches the changeover valve 43 to disable the function to be blocked. For example, a changeover switch 60 is provided above the operation lever of the option operation device 24.

  The controller 40 operates the switching valve 43 in accordance with the signal output from the changeover switch 60 to cut off the discharge pressure of the first hydraulic pump 10a guided to the second regulator 28b, so that the total horsepower control is changed to the individual horsepower control. Switch.

  The third embodiment configured as described above can obtain the same effect as that of the first embodiment, and the operator who intends to drive the option device 3 operates the changeover switch 60 provided in the option operation device 24. Only, it is possible to carry out the individual horsepower control that secures the required flow rate for the option actuator 9.

  The changeover switch 60 is not limited to being provided in the option operation device 24. For example, when the option operating device 24 is constituted by a pedal, the changeover switch 60 may be provided in a pilot operating device of an actuator different from the option actuator 9 operated by a lever. Moreover, you may make it the structure which incorporates the changeover switch 60 in the switch operation part of the monitor arrange | positioned in the cab 1c shown in FIG.

DESCRIPTION OF SYMBOLS 1 Base machine 1a Traveling body 1b Revolving body 1c Driver's cab 2 Work attachment 3 Optional equipment 4 Boom 5 Arm 6 Boom cylinder 7 Arm cylinder 8 Bucket cylinder (attachment actuator)
DESCRIPTION OF SYMBOLS 9 Option actuator 10a 1st hydraulic pump 10b 2nd hydraulic pump 11 Pilot pump 12 Engine 13 Valve apparatus 14-20 Flow control valve 23 Attachment operating device 24 Optional operating device 28a 1st regulator 28b 2nd regulator 30 Main relief valve 31 Pilot relief Valve 33a Pump flow control valve 33b Pump flow control valve 34a Pressure sensor 34b Pressure sensor 40 Controller 41 Switching valve control section 42 Pump flow control section 42a Positive control calculation section 42b Horsepower control calculation section 42c Pump capacity determination section 43 Switching valve 43b switching valve 44a First pump discharge pressure sensor 44b Second pump discharge pressure sensor 50 Torque control valve 60 Changeover switch

Claims (5)

A work attachment in which an optional device can be mounted on the tip, an attachment actuator that drives the work attachment, an option actuator that drives the optional device, and a pressure oil that operates the attachment actuator and the optional actuator. 1 hydraulic pump, 2nd hydraulic pump, engine driving the 1st hydraulic pump and the 2nd hydraulic pump, 1st regulator controlling the displacement volume of the 1st hydraulic pump, and displacement volume of the 2nd hydraulic pump A second regulator that controls the attachment actuator, an attachment operation device that operates the attachment actuator, and an option operation device that operates the option actuator,
The discharge pressure of the second hydraulic pump is guided to the first regulator, the discharge pressure of the first hydraulic pump is guided to the second regulator, and the total horsepower of the first hydraulic pump and the second hydraulic pump is obtained. And a mechanism for controlling the engine within a predetermined horsepower range,
The optional actuator is a hydraulic control device for a construction machine driven by pressure oil discharged from the second hydraulic pump,
A shut-off device for shutting off a discharge pressure of the first hydraulic pump guided to the second regulator;
And a controller for outputting a signal for shutting off a discharge pressure of the first hydraulic pump guided to the second regulator to the shut-off device when the optional device is operated. apparatus. The hydraulic control device for a construction machine according to claim 1,
The shut-off device comprises a switching valve that shuts off a discharge pressure of the first hydraulic pump guided to the second regulator, and a detector that detects an operation of the optional operation device,
The controller shuts off the discharge pressure of the first hydraulic pump that guides the switching valve to the second regulator when it is determined that the optional operation device is operated based on the detection signal output from the detector. A hydraulic control device for a construction machine, wherein the hydraulic control device is operated to a position. A hydraulic control device for a construction machine according to claim 2,
The controller includes a horsepower control calculation unit that calculates the flow rate of the first hydraulic pump,
The horsepower control calculation unit calculates the flow rate of the first hydraulic pump from the discharge pressure of the first hydraulic pump, the discharge pressure of the second hydraulic pump, and the engine horsepower so as not to exceed the maximum absorption torque of the pump. A hydraulic control device for construction machinery. A hydraulic control device for a construction machine according to claim 2,
A hydraulic control device for a construction machine, comprising a changeover switch that switches the changeover valve to disable a function to be shut off. The hydraulic control device for a construction machine according to claim 4,
The controller includes a horsepower control calculation unit that calculates the flow rate of the first hydraulic pump,
The horsepower control calculation unit calculates the flow rate of the first hydraulic pump from the discharge pressure of the first hydraulic pump, the discharge pressure of the second hydraulic pump, and the engine horsepower so as not to exceed the maximum absorption torque of the pump. A hydraulic control device for construction machinery.