JP6759135B2 - Hydraulic control device for construction machinery - Google Patents

Description

The present invention relates to a hydraulic control device for a construction machine such as a hydraulic excavator, which is provided with a work attachment at the tip of which optional equipment can be attached and can control full horsepower.

In construction machines such as hydraulic excavators equipped with work attachments that operate so that the tip is displaced, optional equipment may be attached to the tip. For example, in a general hydraulic excavator, a boom that can be undulated as a work attachment, an arm that is rotatably connected to the tip of the boom in the vertical direction, and an arm that is rotatably connected to the tip of the arm in the vertical direction. However, from the viewpoint of versatility, various optional devices may be installed in place of the bucket. Optional equipment includes concrete vibrators, mowers, twin headers, harvesters, breakers, etc. Unlike the case of a bucket, these optional devices require a fixed flow rate (constant flow rate) as the flow rate supplied to the optional actuator that drives the optional device.

Further, when two or more hydraulic pumps are provided in the above-mentioned hydraulic excavator, a pump control device that performs torque control generally called total horsepower control is provided. In this total horsepower control, for example, the discharge pressures of both the first hydraulic pump and the second hydraulic pump are guided to the respective regulators of the 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 respond to a further increase in the discharge pressure of the hydraulic pump. Each regulator is controlled so as to reduce each push-out volume. As a result, when a plurality of actuators driven by the pressure oil discharged from the first hydraulic pump and the second hydraulic pump are driven independently, the total horsepower assigned to the first hydraulic pump and the second hydraulic pump can be utilized. , It becomes possible to effectively use the prime mover output.

In a construction machine equipped with a pump control device that controls all horsepower, when multiple actuators are driven at the same time, for example, an arm cylinder, which is one of the attachment actuators for driving a work attachment, and another actuator are combinedly driven. 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 other actuators, regardless of the magnitude of the load on the arm cylinder and other actuators. An appropriate flow rate of pressure oil can be supplied to these actuators.

However, if one of the actuators has a high load during the above-mentioned combined drive, the discharge pressure of the hydraulic pump driving the high-load actuator increases, and the first hydraulic pump and the second hydraulic pump and the second actuator increase accordingly. The average discharge pressure of the hydraulic pump increases, the push-out volume of the hydraulic pump supplying pressure oil to the other actuator decreases, and the drive speed of the other actuator slows down.

In Patent Document 1, when it is detected that the discharge pressure of the hydraulic pump that drives the optional actuator has risen to the relief pressure during the combined drive of a plurality of actuators, for example, the optional actuator and the attachment actuator, pressure oil is applied to the optional actuator. 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 supplying hydraulic pump and increasing the discharge flow rate of the hydraulic pump supplying pressure oil to the arm cylinder is disclosed. ing.

Japanese Unexamined Patent Publication No. 2013-249849

By the way, in the concrete vibrator, mower, twin header, harvester, breaker, etc. that compose the optional equipment, unlike the case of the bucket as described above, it is possible to always supply a constant flow rate to the optional actuator that drives the optional equipment. You will need it. However, in full horsepower control, when the optional actuator and the attachment actuator are driven in combination, when the load pressure of the attachment actuator rises and the average discharge pressure of the first hydraulic pump and the second hydraulic pump rises, it is supplied to the optional actuator. The flow rate may decrease and workability may decrease.

As described above, the prior art of Patent Document 1 detects that the pressure of the hydraulic pump supplying pressure oil to the option actuator reaches the relief pressure when the option actuator and the attachment actuator are combinedly driven, and the option actuator is used. By lowering the discharge flow rate of the hydraulic pump that supplies the pressure oil and increasing the discharge flow rate of the hydraulic pump that supplies the pressure oil to the attachment, the flow rate supplied to the attachment actuator is secured. However, in the prior art of Patent Document 1, even when the load pressure of the optional actuator does not reach the relief pressure but becomes high, the discharge flow rate of the hydraulic pump supplying the pressure oil to the optional actuator is reduced. In such a case, the required flow rate is not supplied to the optional actuator, and workability is reduced. The prior art of Patent Document 1 does not give consideration to this point.

In order to solve the above problems, an object of the present invention is to control the total horse pressure, and when the optional actuator and the attachment actuator are driven in combination, the optional actuator is used regardless of the difference in load between the optional actuator and the attachment actuator. The purpose is to provide a hydraulic control device for construction machinery capable of supplying the required flow rate.

In order to achieve this object, the present invention presents a work attachment to which an optional device can be attached to a tip portion, an attachment actuator for driving the work attachment, an optional actuator for driving the optional device, the attachment actuator and the like. The first hydraulic pump and the second hydraulic pump that supply the pressure oil for operating the optional actuator, the engine that drives the first hydraulic pump and the second hydraulic pump, and the push-out volume of the first hydraulic pump are controlled. The first regulator includes a second regulator that controls the push-out volume of the first regulator and the second hydraulic pump, an attachment operating device that operates the attachment actuator, and an optional operating device that operates the optional actuator. the first discharge pressure of the hydraulic pump and the discharge pressure of the second hydraulic pump is led, wherein the second regulator and the discharge pressure of the said and the discharge pressure of the first hydraulic pump second hydraulic pump is led in The attachment actuator has a mechanism for controlling the total horsepower of the first hydraulic pump and the second hydraulic pump within a predetermined horsepower range of the engine, and the attachment actuator is a pressure oil discharged from the first hydraulic pump. The optional actuator is a hydraulic control device for a construction machine driven by the pressure oil discharged from the second hydraulic pump while being driven, and controls the discharge pressure of the first hydraulic pump guided to the second regulator. a blocking device for blocking a signal for interrupting the discharge pressure of the first hydraulic pump is led to the second regulator, and a controller to be output to the blocking device, when the optional device is operated, said controller A signal for shutting off the discharge pressure of the first hydraulic pump guided to the second regulator is output to the shutoff device, and only the discharge pressure of the second hydraulic pump is guided to the second regulator, whereby the second regulator The second regulator, which has been shifted to the individual horsepower control, is characterized in that the push-out volume of the second hydraulic pump is controlled according to the operation amount of the optional operating device .

The hydraulic control device for construction machinery according to the present invention supplies the required flow rate to the optional actuator and reduces the speed of the optional actuator when the optional actuator and the attachment actuator are driven in combination, regardless of the difference in load between the optional actuator and the attachment actuator. It can be operated without occurring to prevent a decrease in workability of the work performed by the optional equipment. In addition, when the optional equipment is not operated, the engine horsepower can be efficiently used by controlling the total horsepower.

It is a side view which shows the hydraulic excavator mentioned as an example of the construction machine provided with the hydraulic control device which concerns on 1st Embodiment of this invention. It is a hydraulic circuit diagram which shows the hydraulic pressure control device which concerns on 1st Embodiment of this invention provided in the hydraulic excavator shown in FIG. It is a block diagram which shows the structure of the controller provided in 1st Embodiment and the apparatus which is related to a controller. It is a flowchart which shows the processing procedure in the controller shown in FIG. It is a figure which shows the characteristic in 1st Embodiment, (a) is a characteristic figure which shows the relationship between a pump pressure and a pump flow rate in total horsepower control, (b) is a pump pressure in a specific control carried out by the controller of this embodiment. The characteristic diagram showing the relationship between the pump flow rate and the pump flow rate, (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 pressure control device which concerns on 2nd Embodiment of this invention. It is a hydraulic circuit diagram which shows the hydraulic pressure control device which concerns on 3rd Embodiment of this invention.

Hereinafter, embodiments of the hydraulic control device for construction machinery according to the present invention will be described 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, which is a swivel body 1a and a swivel body 1b provided so as to be swivelable on the traveling body 1a and having a driver's cab 1c. It includes a base machine 1 composed of and a work attachment 2 attached to the base machine 1. The work attachment 2 includes a boom 4 undulatingly attached to the swivel body 1b of the base machine 1 and an arm 5 attached to the tip of the boom 4 and rotatably connected in the vertical direction. .. An optional device 3 is attached to the tip of the work attachment 2 in place of the bucket normally provided. The optional device 3 is composed of, for example, a breaker.

A telescopic boom cylinder 6 is interposed between the swivel body 1b of the base machine 1 and the boom 4, and the boom cylinder 6 expands and contracts by receiving the supply of pressure oil to move the boom 4 in the upright direction. move. Further, an arm cylinder 7 is opened between the boom 4 and the arm 5, and the arm cylinder 7 is extended by receiving the supply of pressure oil to rotate the arm 5 in the pulling direction (in the direction approaching the boom 4). Move it. The boom cylinder 6 and the arm cylinder 7 form an attachment actuator.

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

As shown in FIG. 2, the hydraulic control device 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 a second hydraulic pump 10b. , And an engine 12 that rotationally drives the pilot pump 11.

Further, a valve device 13 connected to the first hydraulic pump 10a and the second hydraulic pump 10b, and 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. Is equipped with.

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

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

Although not shown, the flow control valves 15, 16, 17 to 19 are also switched by the operation signal pressure from the pilot operation device including the 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 pipeline 26a or the pipeline 26b. When the flow control valves 15, 16, 17 to 19 are switched, the pressure oils of the first hydraulic pump 10a and the second hydraulic pump 10b are applied to the corresponding actuators, for example, the boom cylinder 6 and the arm cylinder 7 shown in FIG. , Or is supplied to a swivel motor and a traveling motor (not shown).

The first hydraulic pump 10a and the second hydraulic pump 10b are sloping plate type or sloping shaft type variable displacement hydraulic pumps. The first hydraulic pump 10a is provided with a first regulator 28a that controls the tilting of the swash plate or the swash axis of the first hydraulic pump 10a, that is, the push-out volume. Similarly, the second hydraulic pump 10b is provided with a second regulator 28b that controls the push-out volume of the second hydraulic pump 10b.

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

The first hydraulic pump 10a and the second hydraulic pump 10b perform torque control called total horsepower control by the first regulator 28a and the second regulator 28b. The discharge pressure of the first hydraulic pump 10a is guided to the first regulator 28a through the pipeline 32a, and the discharge pressure of the second hydraulic pump 10b is guided through the pipeline 32b. Similarly, the discharge pressure of the first hydraulic pump 10a is guided to the second regulator 28b through the pipe line 32a, and the discharge pressure of the second hydraulic pump 10b is guided 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 so as 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. 5 (a). The average discharge pressure PA guided 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 pressures of the first hydraulic pump 10a and the second hydraulic pump 10b increase, the flow rate is controlled to decrease so that the absorbed horsepower of the pumps 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 characteristics are controlled as shown in FIG. 5A so that the pump capacity increases as the control pressure decreases.

Further, the first regulator 28a and the second regulator 28b perform positive control control to increase the pump flow rate according to the increase in the operation signal pressure generated by each pilot operation device including the attachment operation device 23 and the option operation 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, the pump is pumped according to the operating signal pressure generated from the corresponding pilot operating device. The flow rate control valve 33a is switched, and as shown in FIG. 5C, the pump flow rate of the first hydraulic pump 10a is controlled to increase as the operation signal pressure increases. Further, when the flow rate control valves 17 to 20 on the center bypass line 22b are switched, the pump flow rate control valve 33b is switched according to the operation signal pressure generated from the corresponding pilot operating device, and FIG. As shown in (c), the pump flow rate of the second hydraulic pump 10b is controlled to increase as the operation signal pressure increases.

In the first regulator 28a and the second regulator 28b, the pump flow rate obtained by the total horsepower control and the pump flow rate obtained by the positive control control are selected lower for each of the first hydraulic pump 10a and the second hydraulic pump 10b. Therefore, the push-out volume of the first hydraulic pump 10a and the second hydraulic pump 10b is controlled.

As shown in FIG. 2, a detector for detecting the operation amount of the option operation device 24, for example, a pressure sensor 34a, and a detector for detecting the operation amount of the attachment operation device 23, for example, a pressure sensor 34b are provided.

In this first embodiment, a shutoff device for shutting off the discharge pressure of the first hydraulic pump 10a guided to the second regulator 28b and a first hydraulic pump 10a guided to the second regulator 28b when the optional device 3 is operated. It is provided with a controller 40 that outputs a signal for shutting off the discharge pressure of the above to the shutoff device.

The shutoff device includes a switching valve 43 including a solenoid 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. The controller 40 is in a position where the discharge pressure of the first hydraulic pump 10a, which guides the switching valve 43 to the second regulator 28b, is cut off when the operation of the optional device 3 is determined by the detection signal output from the pressure sensor 34a. To operate.

As shown in FIG. 3, the controller 40 has a configuration including 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. And, 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 the 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. The capacity of the first hydraulic pump loop is determined based on the above, and the corresponding control signal is output to the pump flow 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 the 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 with reference to the flowchart of FIG. Now, for example, it is assumed that a combined operation of the option actuator 9 for driving the option device 3 and the bucket cylinder 8 which 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 the 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 turns on the switching valve 43 and outputs a signal for switching to the lower position in FIG. 2, which is the shutoff position. As a result, the discharge pressure of the first hydraulic pump 10a guided to the second regulator 28b is cut off, and the total 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)
Will be.

In normal total horsepower control, for example, when the optional device 3 and the work attachment 2 are operated in combination and the discharge pressure of the first hydraulic pump 10a becomes high, the pump flow rate of the second hydraulic pump 10b is shown in FIG. 5A. Although it drops to Qp, in the control in the first embodiment, the pump flow rate of the second hydraulic pump 10b is Q2 (> Qp) in FIG. 5 (b), so that the optional device 3 and the work attachment 2 are used. When driven at the same time, the required flow rate, which is a constant flow rate, can be supplied to the option actuator 9 of the option device 3.

In 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 that the pump flow rate of the second hydraulic pump 10b is normal. If the pump 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 and 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 1 hydraulic pump 10a and the 2nd hydraulic pump 10b does not exceed 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 being 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 turns off the switching valve 43 and outputs a signal for switching to the upper position in FIG. 3, which is the communication position. As a result, the discharge pressure of the first hydraulic pump 10a is guided to the second regulator 28b, and the normal total horsepower control is restored.

In this first embodiment, as described above, when the optional actuator 9 and the bucket cylinder 8 which is the attachment actuator are collectively driven, the optional actuator 9 is irrespective of the difference in load between the optional actuator 9 and the bucket cylinder 8. It is possible to supply the required flow rate to the cylinder and operate the optional actuator 9 without causing a decrease in speed to prevent a decrease in workability of the work performed by the optional device 3. Further, when the optional device 3 is not operated, the horsepower of the engine 12 can be efficiently used by controlling the total horsepower.

[Second Embodiment]
As shown in FIG. 6, in the second embodiment, the shutoff device that shuts off the discharge pressure of the first hydraulic pump 10a guided to the second regulator 28b is the discharge pressure of the first hydraulic pump 10a led to the second regulator 28b. It is composed of a hydraulic switching valve 43b that shuts off the switching valve 43b and an optional operating device 24 that switches the switching valve 43b. Other configurations are the same as those in the first embodiment.

In this 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. The switching valve 43b is switched to the lower position in FIG. As a result, the discharge pressure of the first hydraulic pump 10a guided to the second regulator 28b is cut off, and the controller 40 switches from the total horsepower control to the individual horsepower control, as in the first embodiment described above. The second embodiment configured in this way also has the same effect as the first embodiment.

[Third Embodiment]
As shown in FIG. 7, this third embodiment has a configuration having a changeover switch 60 for switching the changeover valve 43 so as to disable the function of shutting off. 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 response to the signal output from the changeover switch 60 to shut off the discharge pressure of the first hydraulic pump 10a guided to the second regulator 28b, and changes from total horsepower control to individual horsepower control. Switch.

The third embodiment configured in this way has the same effect as that of the first embodiment, and when an operator who intends to drive the option device 3 operates the changeover switch 60 provided in the option operation device 24. It is possible to carry out individual horsepower control that secures the required flow rate for the optional 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 composed of pedals, a changeover switch 60 may be provided in a pilot operating device of an actuator different from the option actuator 9 operated by the lever. Further, the changeover switch 60 may be incorporated in the switch operation unit of the monitor arranged in the driver's cab 1c shown in FIG.

1 Base machine 1a Traveling body 1b Swinging 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)
9 Optional actuator 10a 1st hydraulic pump 10b 2nd hydraulic pump 11 Pilot pump 12 Engine 13 Valve device 14 to 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 unit 42 Pump flow control unit 42a Positive control calculation unit 42b Horsepower control calculation unit 42c Pump capacity determination unit 43 Switching valve 43b Switching valve 44a 1st pump discharge pressure sensor 44b 2nd pump discharge pressure sensor 50 Torque control valve 60 Changeover switch

Claims (5)

A work attachment to which an optional device can be attached to the tip portion, an attachment actuator for driving the work attachment, an optional actuator for driving the optional device, and a hydraulic oil for operating the attachment actuator and the optional actuator. The push-out volume of the first hydraulic pump, the second hydraulic pump, the engine that drives the first hydraulic pump and the second hydraulic pump, and the push-out volume of the first regulator and the second hydraulic pump that control the push-out volume of the first hydraulic pump. A second regulator for controlling the hydraulic pump, an attachment operating device for operating the attachment actuator, and an optional operating device for operating the optional actuator are provided.
Discharge of the the first regulator and the discharge pressure of the second hydraulic pump and the discharge pressure of the first hydraulic pump is led, wherein the second regulator wherein the discharge pressure of the first hydraulic pump second hydraulic pump It has a mechanism in which the pressure is guided to control the total horsepower of the first hydraulic pump and the second hydraulic pump within a predetermined horsepower range of the engine.
The attachment actuator is driven by the pressure oil discharged from the first hydraulic pump, and the optional actuator is a hydraulic control device of a construction machine driven by the pressure oil discharged from the second hydraulic pump.
A shutoff device that shuts off the discharge pressure of the first hydraulic pump guided to the second regulator, and
A signal for interrupting the discharge pressure of the first hydraulic pump is led to the second regulator, and a controller to be output to the blocking device,
When the optional equipment is operated, the controller outputs a signal for shutting off the discharge pressure of the first hydraulic pump led to the second regulator to the shutoff device, and the second regulator of the second hydraulic pump By guiding only the discharge pressure, the second regulator is shifted to individual horsepower control.
The second regulator, which has shifted to individual horsepower control, is a hydraulic control device for construction machinery, which controls the push-out volume of the second hydraulic pump according to the operation amount of the optional operation device. The hydraulic control device for a construction machine according to claim 1.
The breaking device includes a switching valve that shuts off the discharge pressure of the first hydraulic pump guided to the second regulator, and a detector that detects the operation of the optional operating device.
When the controller determines that the option operating device is operated by the detection signal output from the detector, the controller shuts off the discharge pressure of the first hydraulic pump that guides the switching valve to the second regulator. A hydraulic control device for construction machinery, characterized by being actuated in position. The 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 featuring. The hydraulic control device for a construction machine according to claim 2.
A hydraulic control device for a construction machine, characterized in that it has a changeover switch for switching the changeover valve so as to disable the function of shutting off. In the hydraulic control device for construction machinery 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 featuring.