KR20110073710A - Hydraulic pump control apparatus for construction machinery and hydraulic pump control method for the same - Google Patents

Abstract

PURPOSE: An apparatus and a method for controlling a hydraulic pump of construction machinery are provided to prevent hydraulic impact by gradually changing the required horse power of a hydraulic pump depending on load pressure. CONSTITUTION: An apparatus for controlling a hydraulic pump of construction machinery comprises a horsepower control unit(31), a pressure sensor, and a control unit(60). The horsepower control unit varies the required horsepower of a hydraulic pump(20). The pressure sensor senses the load pressure of working fluid exhausted from the hydraulic pump. The control unit calculates required target horsepower from the sensed load pressure and controls the horsepower control unit.

Description

HYDRAULIC PUMP CONTROL APPARATUS FOR CONSTRUCTION MACHINERY AND HYDRAULIC PUMP CONTROL METHOD FOR THE SAME}

The present invention relates to a hydraulic pump control device and a control method of a construction machine, such as an excavator, in particular, hydraulic pump control device of a construction machine that can prevent the hydraulic shock by gradually increasing the pump required horsepower according to the load pressure of the hydraulic pump And a control method.

In general, a construction machine such as an excavator drives a plurality of work devices such as a boom, an arm, and a bucket by using hydraulic oil discharged from a variable displacement hydraulic pump directly connected to an engine.

The discharge flow rate of the hydraulic pump is controlled by various variables to satisfy various conditions such as work efficiency and fuel economy.

More specifically, the control method of the hydraulic pump is a flow control for controlling the discharge flow rate in accordance with the operation signal input from the operation unit (flow control) and the hydraulic pump in accordance with the discharge pressure of the hydraulic pump so that the required horsepower of the hydraulic pump is constant Constant horse power control for controlling the discharge flow rate and power shift control for controlling the discharge flow rate of the hydraulic pump in accordance with the load state of the engine.

The hydraulic pump is provided with a regulator for the control method as described above, the regulator is a work flow rate control unit for the work flow control, the back horsepower control unit for the back horsepower control, and the horsepower control (power shift control) It includes a horsepower control for. The working flow rate adjusting unit receives the center bypassed negative cone pressure, the pilot pressure of the operation unit, or the load sensing pressure of each actuator to control the discharge flow rate of the hydraulic pump. The back horsepower control unit receives the discharge pressure (load pressure) of the hydraulic pump to control the discharge flow rate of the hydraulic pump according to the set horsepower diagram. Finally, the horsepower control unit controls the discharge flow rate of the hydraulic pump according to the target engine rotation speed set by the dial gauge of the engine and the load of the engine calculated from the current engine rotation speed.

In the hydraulic pump control device as described above, as shown in Figure 1, when the operation amount of the operation unit is rapidly increased, the operation signal is input to the working flow control unit to increase the flow rate of the hydraulic pump rapidly, thereby As the discharge pressure increases rapidly, the required horsepower of the hydraulic pump increases rapidly. Then, the rapidly increased discharge pressure of the hydraulic pump is input to the back horsepower control unit to start to reduce the discharge flow rate of the hydraulic pump.

However, due to the responsive delay time of the back horsepower control unit, the flow rate of the hydraulic pump is reduced by the back horsepower control unit after a certain time from the time when the discharge pressure of the hydraulic pump rises. In this way, the discharge pressure of the hydraulic pump continuously increases during the time when the back horsepower control time is delayed, and the hydraulic shock is generated. Due to such a hydraulic shock, a section in which the required horsepower of the hydraulic pump is rapidly increased, as in section A of FIG. 1.

As such, the sudden increase in horsepower required of the hydraulic pump acts as a large load on the engine, so that the rotation speed of the engine drops rapidly below the set target rotation speed. As such, when the engine rotation speed is sharply reduced, not only the amount of smoke increases but also the vibration increases. In particular, the engine, as in section B of FIG. 1, the engine power increase rate is low in the section in which the turbocharger operation reaches a steady state (turbo charger time lack section), so that the engine rotation speed is further reduced and the amount of smoke is reduced. And the vibration becomes larger.

On the other hand, if the rotational speed of the engine is sharply lowered from the target rotational speed, the horsepower control unit lowers the driving of the hydraulic pump from the highest horsepower (200mA) to the lowest horsepower (600mA) to increase the engine rotational speed. As a result, the flow rate of the hydraulic oil discharged from the hydraulic pump is reduced, which lowers the working efficiency of the construction machine.

2 is an isometric horsepower diagram schematically showing the process as described above. Referring to Figure 2, due to the time delay of the horsepower control time, it can be seen that the flow rate and the pressure is returned to the back horsepower diagram again after the discharge pressure of the hydraulic pump rapidly increases, as in the C diagram.

To summarize the problems caused by the conventional hydraulic pump control device as described above, due to the time delay of the back horsepower control point by the back horsepower control unit occurs a hydraulic shock that the required horsepower of the hydraulic pump is sharply increased. As a result, the engine speed is sharply lowered, so that the amount of smoke and vibration is increased, and in order to restore the engine speed to the target speed, the required horsepower of the hydraulic pump is drastically lowered in the process of driving the hydraulic pump to the minimum horsepower. There is a problem that the work performance of construction machinery is degraded.

The present invention has been made in view of the above-described point, and an object thereof is to provide a hydraulic pump control apparatus and control method for a construction machine which can prevent the occurrence of hydraulic shock due to time delay at the time of back horsepower control. .

Another object of the present invention is to provide a hydraulic pump control apparatus and control method for a construction machine which can improve the working performance of a construction machine by preventing a sudden drop in the rotational speed of the engine even if a large operation amount is input from the operation unit.

Hydraulic pump control apparatus according to the present invention for achieving the above object is to control the hydraulic pump 20 driven by the engine 10, by varying the swash plate angle of the hydraulic pump 20 Horsepower control unit 30 for varying the horsepower required of the hydraulic pump 20; A pressure sensor 50 for detecting a load pressure Pd of the hydraulic oil discharged from the hydraulic pump 20; And calculating a target pump required horsepower from the load pressure Pd sensed by the pressure sensor 50, and the required horsepower of the hydraulic pump 20 gradually increases to the target pump required horsepower for a predetermined time Δt. It includes a control unit 60 for controlling the horsepower control unit 30 to approach.

According to an embodiment of the present invention, when the load pressure Pd sensed from the pressure sensor 50 is the no-load pressure Pd1, the target pump required horsepower is set to the minimum horsepower POmin, and the pressure sensor When the load pressure sensed from 50 is the maximum set pressure Pd2, the target pump required horsepower is set to the maximum horsepower POmax, and the maximum set pressure Pd2 is the maximum horsepower of the hydraulic pump 20 It is less than or equal to the pressure Pd2 at the starting point of back horsepower control of POmax).

In addition, the predetermined time Δt is proportional to the horsepower difference value ΔPO between the current pump required horsepower and the target pump required horsepower of the hydraulic pump 20.

The horsepower control unit 30 is a horsepower control unit 31 for adjusting the swash plate angle of the hydraulic pump 20 in accordance with the pilot pressure input from the pilot pump 33; And an electromagnetic proportional pressure reducing valve 32 for varying an opening amount of a flow path connecting the pilot pump 33 and the horsepower control unit 31 according to the magnitude of the current command value input from the controller 60.

On the other hand, the object as described above is a hydraulic pump control method of a construction machine for controlling the hydraulic pump 20 driven by the engine 10, comprising: calculating the current pump required horsepower of the hydraulic pump 20; Calculating a target pump required horsepower from the load pressure Pd of the hydraulic oil discharged from the hydraulic pump 20; And gradually approaching the required horsepower of the hydraulic pump 20 from the current pump required horsepower to the target pump required horsepower for a predetermined time Δt for a predetermined time (Δt). Can also be achieved.

According to an embodiment of the present disclosure, the hydraulic pump control method may further include calculating the predetermined time Δt from the horsepower difference value ΔPO between the current pump required horsepower and the target pump required horsepower. have.

According to the problem solving means described above, by changing the required horsepower of the hydraulic pump gradually in accordance with the load pressure, it is possible to prevent the hydraulic shock caused by the time delay of the conventional horsepower control time. In addition, by preventing the hydraulic shock, it is possible to prevent the engine rotational speed is sharply lowered by the hydraulic pump load, thereby minimizing the amount of smoke and vibration of the engine.

In addition, there was a problem in that the required horsepower of the hydraulic pump is sharply decreased to reduce the workability of the construction machine in order to restore the engine rotation speed, but by gradually bringing the required horsepower of the hydraulic pump to the target pump required horsepower gradually for a predetermined time. And, it is not necessary to restore the rotational speed of the engine, which can prevent the required horsepower of the hydraulic pump is reduced, thereby improving the workability of the construction machine.

In particular, when the load pressure Pd is the no-load pressure Pd1, the target pump required horsepower is set to the minimum horsepower (POmin) to minimize the load applied to the engine by the hydraulic pump, thereby improving fuel economy. .

In addition, by setting the maximum set pressure Pd2 at which the target pump required horsepower becomes the maximum horsepower POmax to be less than or equal to the pressure Pd2 of the back horsepower control start point of the maximum horsepower POmax of the hydraulic pump, When the horsepower reaches the target pump required horsepower, the discharge flow rate of the hydraulic pump can be as large as possible, thereby further improving workability.

Further, by setting the predetermined time Δt to be proportional to the horsepower difference value ΔPO of the current pump required horsepower and the target pump required horsepower of the hydraulic pump, the horsepower quickly when the horsepower difference value ΔPO is small. If the control is possible and the horsepower difference value ΔPO is large, sufficient control time is obtained so that the hydraulic shock does not occur.

On the other hand, by configuring the horsepower control unit with the electronic proportional pressure reducing valve for varying the opening amount of the flow path connecting the horsepower control unit, the pilot pump and the horsepower control unit, it is possible to apply the spirit of the present invention to a general hydraulic system universally .

Hereinafter, a hydraulic pump control apparatus and a hydraulic pump control method of a construction machine according to an embodiment of the present invention with reference to the accompanying drawings will be described in detail.

3, the hydraulic pump control apparatus of a construction machine according to an embodiment of the present invention as a device for controlling the hydraulic pump 20 driven by the engine 10, the hydraulic pressure in accordance with the input horsepower control signal The horsepower control unit 30 for varying the horsepower of the hydraulic pump 20 by varying the swash plate angle of the pump 20, and the pressure sensor 50 for detecting the pressure of the hydraulic oil discharged from the hydraulic pump 20 And, the control unit 60 for outputting the horsepower control signal to the horsepower control unit 30.

The hydraulic pump 20 is a variable pump having a variable discharge flow rate due to the inclination of the swash plate 23, and the hydraulic pump 20 is provided with a regulator 40 for adjusting the swash plate 23.

The regulator 40 has a working horsepower control unit 41 for varying the discharge flow rate of the hydraulic pump 20 in accordance with a signal for the operation amount of the operation unit 42, and the horsepower required of the hydraulic pump 20 is constant It includes a horsepower control unit 43 for maintaining as, and a horsepower control unit 31 for adjusting the required horsepower of the hydraulic pump 20.

The working flow rate adjusting unit 41 is for adjusting the discharge flow rate of the hydraulic pump 20 according to a signal corresponding to the operation signal of the operation unit 42, and is proportional to the magnitude of the operation signal of the operation unit 42. The discharge flow rate of the hydraulic pump 20 is increased. Here, the signal corresponding to the operation signal of the operation unit 42 is the negative pressure that is the bypass pressure passing through the main control valve 21, the posicon pressure which is a pilot pressure according to the operation of the operation unit 42 and each It may be composed of a signal for any one selected from the load sensing pressure of the actuator 22.

The back horsepower control unit 43 adjusts the discharge flow rate of the hydraulic pump 20 according to the discharge pressure of the hydraulic pump 20 to maintain the required horsepower of the hydraulic pump 20. Here, the back horsepower is variable by the horsepower control unit 31. Accordingly, the back horsepower control unit 43 adjusts the discharge flow rate of the hydraulic pump 20 along the variable back horsepower diagram of the current state.

The horsepower control unit 31 is for changing the required horsepower of the hydraulic pump 20, the pilot pressure discharged from the pilot pump 33 is applied. Here, the electromagnetic proportional pressure reducing valve 32 is installed between the horsepower control part 31 and the pilot pump 33, and the pilot pump 33 and the horsepower control part by the electromagnetic proportional pressure reducing valve 32. The opening degree of the flow path which connects between 31 is adjusted. The electromagnetic proportional pressure reducing valve 32 is converted according to the current command value output from the controller 60. Therefore, the horsepower control unit 31 is to change the swash plate angle of the hydraulic pump 20 in accordance with the current command value output from the control unit 60.

In this embodiment, the horsepower control unit 31 and the electromagnetic proportional pressure reducing valve 32 is defined as a horsepower control unit 30, unlike the embodiment is the horsepower control unit 31 and the electromagnetic proportional pressure reduction The valve 32 may be implemented as one electromagnetic proportional pressure reducing valve in the electronically controlled pump. Therefore, the horsepower control unit 30 may not only be composed of the horsepower control unit 31 and the electromagnetic proportional pressure reducing valve 32 but also may be composed of one electromagnetic proportional pressure reducing valve in the electronically controlled pump.

Looking at the operation of the horsepower control unit 30 in more detail, when the high current command value (for example, 600mA) is output from the control unit 60 to the electromagnetic proportional pressure reducing valve 32 the electromagnetic proportional pressure reducing valve Reference numeral 32 increases the flow opening amount of the pilot pump 33 and the horsepower control unit 31. Then, the horsepower control unit 31 adjusts the swash plate angle to reduce the discharge flow rate of the hydraulic pump 20 to reduce the required horsepower of the hydraulic pump 20.

Contrary to the above, when the low current command value (for example, 200 mA) is output to the electromagnetic proportional pressure reducing valve 32, the electromagnetic proportional pressure reducing valve 32 is the pilot pump 33 and the horsepower control part 31. Reduce the opening amount of the flow path. Then, the horsepower control unit 31 increases the horsepower of the hydraulic pump 20 by adjusting the swash plate angle so that the discharge flow rate of the hydraulic pump 20 increases.

The pressure sensor 50 detects the discharge pressure of the hydraulic pump 20 and transmits it to the control unit 60. The discharge pressure of the hydraulic pump 20 may be represented as a load pressure because it may vary depending on the load transmitted from the actuator 22 through the main control valve 21.

The controller 60 calculates a current command value to be output to the electromagnetic proportional pressure reducing valve 32 and outputs it to the electromagnetic proportional pressure reducing valve 32. More specifically, as shown in FIG. 4, the target pump required horsepower for the load pressure Pd sensed by the pressure sensor 50 is set in the controller 60. Here, the target pump required horsepower may be converted into a current command value output to the electromagnetic proportional pressure reducing valve 32. Since the system of the present embodiment is a negative system in which the required horsepower of the hydraulic pump 20 rises in inverse proportion to the current command value, in FIG. 4, the magnitudes of the current command value and the target pump required horsepower vary in opposite directions depending on the load pressure Pd.

Moreover, the pump horsepower increase / decrease rate is set in the said control part 60 like FIG. The pump horsepower increase and decrease rate of FIG. 5 represents a time for increasing the current pump required horsepower from the current pump required horsepower of the hydraulic pump 20 to the target pump required horsepower. As the horsepower difference value ΔPO between the current pump required horsepower and the target pump required horsepower is increased, the pump The horsepower rise time is set to be large. In addition, the controller 60, as shown in Fig. 6, the pump required horsepower increase rate for the selected specific rise time (DELTA) t1 is set. Pump horsepower increase rate as shown in Figure 6 may be stored in the form of a table for the rise time as a value respectively set according to the size of the rise time.

As described above, when the load pressure Pd is input from the pressure sensor 50, the controller 60 calculates a target pump required horsepower from the set value as shown in FIG. 4. Then, the controller 60 calculates a horsepower difference value ΔPO between the current pump required horsepower of the hydraulic pump 20 and the calculated target pump required horsepower. The current pump required horsepower of the hydraulic pump 20 may be calculated from the load pressure Pd sensed by the pressure sensor 50 and the swash plate angle of the current hydraulic pump 20.

When the horsepower difference value ΔPO is calculated, the controller 60 calculates the rise time Δt from the pump horsepower increase and decrease rate as shown in FIG. 5. When the rise time Δt is calculated, the horsepower increase rate as shown in FIG. 6 is calculated.

When the calculation of the horsepower increase rate is completed, the control unit 60 raises the current pump required horsepower to the target pump required horsepower at the calculated rise rate during the calculated rise time Δt. That is, the controller 60 gradually raises the required horsepower of the hydraulic pump 20 to the target pump required horsepower for a predetermined time.

On the other hand, as shown in Figure 4, the target pump required horsepower is set to the minimum horsepower (POmin), when the load pressure (Pd) detected by the pressure sensor 50 is the no-load pressure (Pd1), the load pressure If Pd is the maximum set pressure Pd2, the maximum horsepower POmax is set. At this time, as shown in Figure 7, the maximum set pressure (Pd2) is set equal to or less than the horsepower control start point (Pd2) of the maximum horsepower (POmax) of the hydraulic pump 20, which is the hydraulic pump ( When the required horsepower of 20) reaches the target pump required horsepower, the discharge flow rate of the hydraulic pump 20 is secured as large as possible to improve the working performance of the construction machine.

Hereinafter, the hydraulic pump control method having the configuration as described above will be described in detail.

Referring to FIG. 8, first, in a state in which there is no operation amount of the operation unit 42, the load pressure Pd sensed by the pressure sensor 50 is the no load pressure Pd1. When the no-load pressure Pd1 signal is transmitted to the control unit 60, the control unit 60 calculates the target pump required horsepower as the minimum horsepower POmin from FIG. 4 to supply the maximum current command value to the electromagnetic proportional pressure reducing valve 32. (For example, 600 mA) is output. Then, the electromagnetic proportional pressure reducing valve 32 opens the opening amount of the flow path connecting the horsepower control unit 31 and the pilot pump 33 to the maximum, whereby the horsepower control unit 31 opens the hydraulic pump 20. Run at minimum horsepower (POmin).

In this state, as shown in FIG. 8, when the operation amount of the operation unit 42 is rapidly increased, a signal for the operation amount is applied to the working flow rate adjusting unit 41. Then, the working flow rate adjusting unit 41 rapidly increases the flow rate of the hydraulic pump 20. However, even if the flow rate increases sharply, since the horsepower control unit 31 drives the hydraulic pump 20 to the minimum horsepower POmin, the flow rate does not increase rapidly or the load pressure Pd increases as in the prior art. However, in order to increase the driving force of the work device, it is necessary to increase the required horsepower of the hydraulic pump 20 through the horsepower control unit 31.

To this end, the controller 60 receives the increased load pressure Pd sensed by the pressure sensor 50 and calculates a target pump required horsepower according to the load pressure Pd received from the set value as shown in FIG. 4. Then, the controller 60 calculates a horsepower difference value ΔPO between the current pump required horsepower and the target pump required horsepower of the hydraulic pump 20, and calculates a horsepower difference value (calculated from the set values shown in Figs. The rise time Δt and the rate of rise relative to ΔPO) are calculated. Thereafter, the controller 60 gradually increases the current pump required horsepower to the target pump required horsepower calculated at the rising rate calculated during the rise time Δt.

As such, the controller 60 gradually raises the required horsepower of the hydraulic pump 20 to the target pump required horsepower calculated from the minimum horsepower POmin, so that the hydraulic shock does not occur as shown in FIG. 8. . In addition, as shown in Figure 8, it is possible to minimize the amount of smoke by preventing a sharp drop in the rotational speed of the engine, as well as to reduce the vibration caused by the engine speed decreases.

On the other hand, conventionally, when the engine rotational speed is lower than the target engine rotational speed set from the dial gauge 11, the horsepower control to lower the horsepower required of the hydraulic pump 20 to the minimum to reduce the workability of the construction machine, this embodiment In the example, the degree of reduction in the rotational speed of the engine is small, and the workability of the construction machine can be improved by gradually increasing the required horsepower of the hydraulic pump 20 from the minimum horsepower to the target pump required horsepower.

9, the process of raising the hydraulic pump 20 from the minimum horsepower (POmin) to the target pump required horsepower is schematically shown in a pressure-flow diagram (back horsepower diagram). Referring to FIG. 9, the controller 60 increases the horsepower of the hydraulic pump 20 from the minimum horsepower POmin to the target pump horsepower during the rise time Δt, and adjusts the horsepower during the rise time Δt. The unit 43 performs back horsepower control along a variable back horsepower diagram. As such, as the horsepower control and the horsepower control of the hydraulic pump 20 are performed at the same time, the horsepower, the flow rate and the load pressure are changed as shown in FIG. 9, thereby preventing the hydraulic shock as shown in FIG. 2. It can be seen.

Figure 10a shows the boom rising speed and the engine rotational speed by the conventional hydraulic pump control device, Figure 10b shows the amount of change in the boom rising speed and engine rotational speed by the hydraulic pump control device according to the present embodiment.

Referring to FIG. 10A, in the related art, the boom raising speed is rapidly increased due to the rapid flow rate and the load pressure. However, due to the hydraulic shock, the engine rotational speed is drastically lowered, as in the E region, and thus horsepower control is started to lower the required horsepower of the hydraulic pump 20 to the minimum horsepower. As a result, a section in which the boom rising speed is rather reduced occurs in the D region. As a result, not only the workability of the construction machine is very deteriorated, but also the amount of smoke and the vibration are large.

However, referring to FIG. 10B, in this embodiment, the increase rate of the boom ascending speed is slightly lower than that in FIG. 10A, but the boom ascending speed is not lowered in the F section and the engine rotation speed is not significantly reduced as in the G section. . As a result, it is possible not only to improve the workability of construction machinery but also to minimize the generation of soot and vibration.

On the other hand, when the load pressure does not vary by rising to the reference pressure, horsepower control of the hydraulic pump 20 can be performed in consideration of the engine rotation speed. In addition, even when a change in load pressure occurs and the engine rotational speed is changed, horsepower control of the hydraulic pump 20 may be performed in consideration of the engine rotational speed.

1 is a graph schematically showing a pump discharge flow rate and required horsepower, an engine output and a rotation speed, and a horsepower control current command value in accordance with a conventional hydraulic pump control device under sudden operation conditions of an operation unit;

FIG. 2 is a graph showing a control process of FIG. 1 in a pressure-flow diagram (back horsepower diagram) of a hydraulic pump;

3 is a conceptual view schematically showing a hydraulic pump control device for a construction machine according to an embodiment of the present invention;

4 is a graph schematically showing a target pump required horsepower and a current command value with respect to a load pressure set in the controller of FIG. 3;

5 is a graph schematically illustrating a rise time with respect to a horsepower difference value between a target pump power required and a current pump power required by the controller of FIG. 3;

FIG. 6 is a graph schematically illustrating a horsepower increase rate with respect to a specific horsepower difference value set in the controller of FIG. 3;

FIG. 7 is a graph schematically showing a maximum back horsepower diagram and a minimum back horsepower diagram of the hydraulic pump illustrated in FIG. 3;

8 is a graph schematically showing the pump discharge flow rate and required horsepower, engine output and rotational speed according to the hydraulic pump control apparatus shown in FIG.

9 is a graph showing the control process of FIG. 8 in the pressure-flow diagram (back horsepower diagram) of the hydraulic pump;

10A is a graph illustrating measurement of the boom rising speed and the engine rotation speed according to the control process of FIG. 1;

FIG. 10B is a graph illustrating measurement of the boom rising speed and the engine rotation speed according to the control process of FIG. 8.

DESCRIPTION OF THE REFERENCE NUMERALS OF THE DRAWINGS

10; Engine 20; Hydraulic pump

30; Horsepower control unit 31; Horsepower regulator

32; Electromagnetic proportional pressure reducing valve 33; Pilot pump

40; Regulator 50; Pressure sensor

60; Control unit ΔPO; Horsepower difference

Δt; Rise time, preset time POmin; Pump minimum horsepower

POmax; Pump maximum horse power Pd; Load pressure

Pd1; No load pressure Pd2; Set pressure

Claims (6)

In the hydraulic pump control device of a construction machine for controlling the hydraulic pump 20 driven by the engine 10, A horsepower control unit (30) for varying horsepower of the hydraulic pump (20) by varying the swash plate angle of the hydraulic pump (20); A pressure sensor 50 for detecting a load pressure Pd of the hydraulic oil discharged from the hydraulic pump 20; And The target pump required horsepower is calculated from the load pressure Pd sensed by the pressure sensor 50, and the required horsepower of the hydraulic pump 20 is gradually approached to the target pump required horsepower for a predetermined time Δt. Hydraulic pump control device for a construction machine, characterized in that it comprises a control unit (60) for controlling the horsepower control unit (30). The method of claim 1, When the load pressure Pd sensed by the pressure sensor 50 is the no load pressure Pd1, the target pump required horsepower is set to the minimum horsepower POmin, If the load pressure sensed from the pressure sensor 50 is the maximum set pressure Pd2, the target pump required horsepower is set to the maximum horsepower POmax, The maximum set pressure (Pd2) is a hydraulic pump control device of the construction machine, characterized in that less than or equal to the pressure (Pd2) of the starting horsepower control starting point of the maximum horsepower (POmax) of the hydraulic pump (20). The method of claim 1, The predetermined time period Δt is proportional to the horsepower difference value ΔPO between the current pump required horsepower and the target pump required horsepower of the hydraulic pump 20, the hydraulic pump control device for a construction machine. The method of claim 1, The horsepower control unit 30, A horsepower control unit 31 for adjusting the swash plate angle of the hydraulic pump 20 according to the pilot pressure input from the pilot pump 33; And It characterized in that it comprises an electromagnetic proportional pressure reducing valve 32 for varying the opening amount of the flow path connecting the pilot pump 33 and the horsepower control unit 31 according to the magnitude of the current command value input from the control unit 60 Hydraulic pump control device for construction machinery. In the hydraulic pump control method of the construction machine for controlling the hydraulic pump 20 driven by the engine 10, Calculating a current pump required horsepower of the hydraulic pump 20; Calculating a target pump required horsepower from the load pressure Pd of the hydraulic oil discharged from the hydraulic pump 20; And Progressively approaching the required horsepower of the hydraulic pump (20) from the current pump required horsepower to the target pump required horsepower for a predetermined time (Δt). The method of claim 5, And calculating the predetermined time [Delta] t from the horsepower difference value [Delta] PO of the current pump required horsepower and the target pump required horsepower.

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