JP3308073B2 - Engine speed control device for hydraulic construction machinery - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a motor speed control device for a hydraulic construction machine such as a hydraulic shovel.

[0002]

2. Description of the Related Art Conventionally, for example, Japanese Patent Application Laid-Open No. 57-163
Japanese Patent Publication No. 701 discloses a motor rotation speed control device that corrects an engine rotation speed set in advance by a fuel lever or the like according to a load pressure. JP-A-4-25850
Japanese Patent Application Laid-Open No. 5 (1999) -2005 discloses a motor rotation speed control device of a hydraulic construction machine capable of load sensing control for maintaining a discharge pressure of a variable displacement hydraulic pump driven by a motor at a fixed pressure higher than a load pressure of a hydraulic actuator. ,
When the discharge pressure of the hydraulic pump detected by the discharge pressure sensor is equal to or higher than a predetermined value, and when the differential pressure detected by the differential pressure detection sensor is equal to or lower than the predetermined value even when the discharge pressure is lower than the predetermined value, the target A device that adjusts the engine speed to a speed higher than a target speed set by a speed setting device is disclosed.

[0003]

However, in the above-described conventional prime mover rotation speed control device, the load value at which the correction of the rotation speed of the prime mover is started, and the rotation speed correction value for the load, regardless of the work content. Since the size of is fixed, there are the following problems.

[0004] For example, hydraulic shovels have a wide variety of work forms such as excavation work, hanging load work, leveling work and the like, and the characteristics to be corrected differ according to the load for each work. Also,
Depending on the operator's preference, the characteristics to be corrected differ depending on the load, and there are some operators who attach importance to the amount of work and others who attach importance to fuel efficiency. However, in the conventional prime mover rotational speed device, the load and the rotational speed correction value have a one-to-one correspondence, and it has not been possible to meet such various demands.

[0005] Further, the rotational speed correction value once increased is returned to zero after the elapse of a predetermined delay time.
This delay time is constant and may not match the work mode or operator's preference.

SUMMARY OF THE INVENTION An object of the present invention is to provide a prime mover rotational speed control device for a hydraulic construction machine, wherein the correction of the prime mover rotational speed based on a load can be set in accordance with a work form or an operator's preference.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIGS. 1 to 4 showing an embodiment, the present invention is directed to a variable displacement hydraulic pump 1 driven by a prime mover 27 and a hydraulic pump 1 according to the present invention. The hydraulic actuator 4 driven by the oil discharged from the engine and the motor 2 according to the operation of the operating means 57a
7, a target rotation speed setting means 81 for setting a target rotation speed,
Detecting means 52 for detecting a load on the hydraulic actuator;
Rotation speed correction means 82 for correcting the set target rotation speed based on the detected load of the hydraulic actuator.
And a motor control means 28, 88 for controlling the motor 27 so that the corrected target rotation speed is obtained. The above object is achieved by providing adjusting means 58a to 58d and 821a to 821d for adjusting the correction characteristics of the rotation speed by the rotation speed correction means 82. Adjusting means 58a to 58
d, 821a to 821d are the rotation start correction load,
This is for adjusting the magnitude of the rotation speed correction value with respect to the load. The rotation speed correction means 82 may include a gradual reduction means 824 that gradually reduces the rotation speed correction value to zero after a set delay time has elapsed, and in this case, the adjustment means adjusts the delay time. is there.

[0008]

Function: Adjusting means 58a to 58d, 821a to 821d
Adjusts the rotation speed correction characteristic. Rotation speed correction means 8
2 corrects the rotation speed according to the adjusted correction characteristic.

In the means and means for solving the above problems which explain the constitution of the present invention, the drawings of the embodiments are used to make the present invention easy to understand. However, the present invention is not limited to this.

[0010]

【Example】

-First Embodiment- An embodiment in which the present invention is applied to a wheel-type hydraulic excavator will be described with reference to FIGS. FIG. 2 is a diagram showing an overall configuration of a drive control device of the hydraulic shovel, and FIG. 3 is a diagram showing a pilot operation circuit thereof, where 1 is an engine (motor).
27 is a variable displacement hydraulic pump driven by 27. The rotation speed of the engine 27 is determined by the governor lever 27 of the governor 27a.
It is controlled by rotating b by a pulse motor 28. The discharge oil of the variable displacement hydraulic pump 1 according to the engine speed is guided to the hydraulic motor 4 via the traveling control valve 2 and to the working hydraulic cylinder 21 via the working control valve 20. .

Now, for example, when the forward / reverse switching valve 8 (FIG. 3) is switched to the forward position (F position) and the pedal 6a of the pilot valve 6 is operated, the oil discharged from the hydraulic pump 5 causes the pilot port 2a of the pilot type control valve 2 to operate. The control valve 2 is switched by a stroke amount corresponding to the pilot oil pressure. As a result, the oil discharged from the variable displacement hydraulic pump 1
1, the pressure is supplied to the hydraulic motor 4 through the pressure compensating valve 23 and the control valve 2, and the vehicle runs. The speed of the vehicle depends on the depression amount of the travel pedal 6a.

When the pedal 6a is released during traveling, the pilot valve 6 shuts off the pressure oil, and its outlet port communicates with the tank 10. As a result, the pressure oil acting on the pilot port 2a returns to the tank 10 via the forward / reverse switching valve 8, the slow return valve 7, and the pilot valve 6. At this time, since the return oil is throttled by the throttle of the slow return valve 7, the vehicle is gradually decelerated while the pilot control valve 2 is gradually switched to the neutral position.

When the work lever 58 is operated, the hydraulic pilot-type work control valve 20 is switched by the pressure reduced by the pressure reducing valve 59 in accordance with the operation amount, and the oil discharged from the hydraulic pump 1 is supplied to the pipeline 92. , The pressure is guided to the working hydraulic cylinder 21 via the pressure compensating valve 24 and the control valve 20, and the working attachment such as a boom is moved up and down by the expansion and contraction of the hydraulic cylinder 21. Here, the pressure compensating valves 23 and 24 are
It is provided for independently compensating the operation of the hydraulic motor 4 and the hydraulic cylinder 21, and supplies the pressure oil from the hydraulic pump 1 to each actuator when the difference between the inlet and outlet pressures of the respective control valves is equal to or more than a predetermined value.

The tilt angle of the variable displacement hydraulic pump 1, that is, the displacement volume, is controlled by a tilt angle control device 40.
The tilt angle control device 40 controls a piston position by a hydraulic pump 41 driven by the engine 27, a pair of solenoid valves 42, 43, and pressure oil from the hydraulic pump 41 according to switching of the solenoid valves 42, 43. The tilt angle of the hydraulic pump 1 is controlled according to the piston position of the servo cylinder 44. Here, the pair of solenoid valves 42 and 43 are switch-controlled by the controller 50.

Reference numeral 51 denotes a tilt angle sensor for detecting the tilt angle θs of the hydraulic pump 1, and 52 denotes a discharge pressure Pp of the hydraulic pump 1.
Is a pressure sensor for detecting the rotation speed N of the engine 27.
r is a rotational speed sensor for detecting the discharge pressure of the hydraulic pump 1 and the maximum load pressure of the actuator (the hydraulic motor 4).
Is the larger of the load pressure of the hydraulic cylinder 21 and the load pressure of the hydraulic cylinder 21 and is selected by the shuttle valve 29), that is, the LS differential pressure ΔPLS. Reference numeral 55 denotes a potentiometer for detecting the rotation amount Nθ of the governor lever 27b. The detection results of these sensors are input to the controller 50. 5
Reference numeral 7 denotes a rotation speed setting device for commanding a target rotation speed X in accordance with a manual operation of the fuel lever 57a, and the command signal is also input to the controller 50.

The controller 50 includes a first control circuit unit 60 as shown in FIG. 4 and a second control circuit unit 80 as shown in FIG.
And The control circuit unit 60 includes a load sensing control unit (hereinafter, an LS control unit) 61 and a torque control unit 62.
, A selection unit 63, and a servo control unit 64. LS
The control unit 61 determines the target differential pressure ΔPLSR and the differential pressure sensor 54
The deviation Δ (PLS) from the LS differential pressure ΔPLS detected in the step is calculated, and the variation Δθ of the target value is calculated from the deviation Δ (PLS).
L is calculated and integrated to obtain and output a target pump tilt angle θL for load sensing control.

The torque control unit 62 controls the engine speed Nr detected by the speed sensor 53 and the potentiometer 5.
5, a deviation ΔN from the governor lever position Nθ is calculated, and from this deviation ΔN, a target torque Tpo for preventing engine stall is calculated, and the target torque Tpo is calculated.
Is multiplied by the reciprocal of the pump discharge pressure Pp detected by the pressure sensor 52, and the value θps is filtered by a temporary delay element to obtain a target pump tilt angle θT for input torque limiting control. Ask.

The selecting section 63 determines the two target tilt angles θ
The smaller of L and θT is selected and the servo controller 6
4 is output. The servo control unit 64 compares the selected tilt angle command value θr with the tilt angle feedback value θs detected by the tilt angle sensor 51, and determines the pump tilt angle θs as the tilt angle command. The tilt angle control device 40 is controlled to match the value θr.

Here, according to the load sensing control, the displacement of the variable displacement hydraulic pump 1 (hereinafter, also referred to as the tilt angle) is controlled so that the LS differential pressure becomes a constant value.
Since the pump pressure is maintained higher than the load sensing pressure by a predetermined target value, the pump tilt angle is controlled so that the pump discharge flow rate is equal to the required flow rate of the control valve 2 or 20, and an extra flow rate is discharged. This eliminates waste due to throttle loss and improves fuel efficiency and operability. Further, according to the input torque limiting control, the torque of the hydraulic pump 1 is maintained within the range of the output torque of the engine 27, and the overload on the engine 27 is prevented.

On the other hand, in the second control circuit section 80 shown in FIG. 5, reference numeral 81 denotes a target rotation speed calculating section, which is a target rotation speed corresponding to a signal X corresponding to the displacement of the fuel lever 57a of the rotation speed setting device 57. Determine the number Nx. The displacement amount X and the target rotation speed Nx are set such that the target rotation speed N
x is set so as to linearly increase from the idle speed Ni.

Reference numeral 82 denotes a rotation speed correction value calculation unit which outputs signals x1 to x4 proportional to the operation amounts of the rotation speed correction characteristic adjustment dials 58a to 58d in accordance with the output pressure Pp of the hydraulic pump 1 which is the output of the pressure sensor 52. A rotation speed correction value ΔN is obtained from the correction characteristics adjusted by x4. These dials 58a to 58d may be provided in the driver's seat so that the operator can freely operate them, or may be provided in the form of a so-called hidden switch so that only a service person can operate them.

FIG. 1 shows the details of the rotation speed correction value calculating section 82. Reference numeral 820 denotes a programmable function generator for forming basic characteristics of the rotation speed correction value with respect to load pressure.
To 821d are rotational speed correction characteristic adjustment dials 58a to 58d.
It is a function generator that receives signals x1 to x4 from 8d and outputs adjustment signals S1 to S4, respectively, which will be described later. When the pump pressure increases beyond the rotation speed increase pressure set value Pu, the function generator 820 increases the increase characteristic NCup shown in the figure.
Then, a rotation speed correction value ΔN1 corresponding to the pump pressure is output. On the other hand, when the pump pressure decreases by a predetermined value or more,
That is, when the current value decreases by (Pu−Pd) or more, the rotation speed correction value ΔN1 corresponding to the pump pressure is output according to the illustrated decrease characteristic NCdw.

Here, the pressure Pd at which the rotation speed correction value ΔN1 becomes zero is called a rotation speed down set value, and the rotation speed down set value is a rotation speed down pressure setting dial 58.
a function generator 82 having as input the signal x1 output from
It is set by the adjustment signal S2 from 1a. Further, the rotation speed increasing pressure set value Pu is set by the adjustment signal S2 from the function generator 821b to which the signal x2 output from the rotation speed increasing pressure setting dial 58b is input. Pu and Pd
Is the hysteresis, and the increased rotation speed is not reduced unless the pump pressure is reduced by the difference or more, thereby preventing hunting.

The adjustment signal S3 from the function generator 821c to which the signal x3 output from the rotation-up amount setting dial 58c is input is a rotation speed correction value ΔN with respect to the pump pressure.
The adjustment signal S3 is multiplied by the output ΔN1 of the function generator 821 by the multiplier 822 to obtain the output ΔN2. The output ΔN2 is stored in the memory 823 at a predetermined timing, and the output of the memory 824 is input to the function generator 824. Function generator 824
Is to gradually decrease the input rotation speed ΔN2 so that the rotation speed correction value ΔN2 becomes zero when a delay time t0 set by an adjustment signal S4 described later elapses, and outputs a rotation speed correction value ΔN3. This output ΔN3 is supplied to the changeover switch 82
5 is connected to one input terminal. The adjustment signal S4 is output from a function generator 821d that receives the signal x4 output from the delay time setting dial 58d as an input, and the function generator 8
24 delay time t0 is set. This function generator 824
Is that ΔN2 input at a predetermined timing is the delay time t
ΔN2 is gradually reduced so that it becomes zero when 0 passes, and Δ
Output as N3. Accordingly, function generator 824 is a programmable function generator.

The output ΔN2 of the multiplier is changed by the changeover switch 8
25, and is input to a deviator 826, which takes a deviation ΔΔN between the previous rotation speed correction value ΔNold and the multiplier output ΔN2. This ΔΔN is the value of switch 8
When ΔΔN is positive, the switch 825 is switched to the position a, and when ΔΔN is negative, the switch 825 is switched to the position b. Changeover switch 82
5 is output to the switch 89 in FIG.
7 is stored. The output ΔNold of the memory 827 is the previous value of the rotation speed correction value.

As shown in FIG. 5, the rotation speed correction value ΔN obtained by the rotation speed correction value calculation unit 82 is input to a + input terminal of an addition unit 87 via a selection switch 89, where the target value The target rotation speed command value N is added to the rotation speed Nx.
y. The target rotation speed command value Ny is compared with a signal of the displacement amount Nθ of the governor lever 27b detected by the potentiometer 55 by the servo control unit 88, and the pulse motor 28 is adjusted according to the procedure shown in FIG. Is controlled. The selection switch 89 can be opened and closed by an operation of an operator, and can be opened and closed in response to a signal indicating a work mode.

In FIG. 6, first, in step S21, the target rotational speed command value Ny and the governor lever displacement amount Nθ are read, and the process proceeds to step S22. In step S22, the result of Nθ−Ny is stored in the memory as the rotational speed difference A, and in step S23, it is determined whether or not | A | ≧ K using the predetermined reference rotational speed difference K. If affirmative, the process proceeds to step S24, where it is determined whether or not the rotation speed difference A> 0. If A> 0, the governor lever displacement amount Nθ is larger than the target rotation speed command value Ny, that is, the control rotation speed is equal to the target rotation speed. Therefore, in step S25, a signal for instructing the motor to rotate in reverse is sent to the pulse motor 2 to reduce the engine speed.
8 is output. As a result, the pulse motor 28 rotates in the reverse direction, and the rotation speed of the engine 27 decreases.

On the other hand, if A ≦ 0, the governor lever displacement amount N
Since θ is smaller than the target rotation speed command value Ny, that is, the control rotation speed is lower than the target rotation speed, a signal for commanding the motor to rotate forward is output in step S26 to increase the engine rotation speed. As a result, the pulse motor 28 rotates forward and the rotation speed of the engine 27 increases. If step S23 is denied, the process proceeds to step S27 to output a motor stop signal, whereby the rotation speed of the engine 27 is maintained at a constant value. After executing steps S25 to S27, the process returns to the beginning.

In the above configuration, when the discharge pressure Pp of the hydraulic pump 1 detected by the pressure sensor 52 exceeds a predetermined value Pu (FIG. 1), the rotation speed correction value Δ corresponding to the pressure Pu.
N1 is output from function generator 820. This correction value Δ
N1 is multiplied by a rotation-up amount adjustment signal S3 in a multiplier 822, and a correction value ΔN2 is output. This correction value ΔN2
Is larger than the previous value ΔNold, the output ΔΔN of the deviation device 826 becomes positive, and the changeover switch 825 is switched to the contact point a. Therefore, the ΔN2 output from the multiplier 822 is set as the correction value ΔN, and the rotation speed correction value calculator 82 Output from

The correction value ΔN is calculated by the adder 87
It is added to the target rotation speed Nx set by the target rotation speed calculation unit 81. Therefore, the target rotation speed command value Ny becomes higher than the target rotation speed Nx, the actual rotation speed of the engine 27 increases accordingly, and the discharge of the hydraulic pump 1 is performed in a range where the flow rate of the control valve is not saturated. The flow rate increases.

On the other hand, once the pump pressure P exceeds Pu,
When p decreases by (Pu−Pd) or more, the function generator 82
ΔN1 output from 0 becomes smaller in accordance with the weight loss characteristic NCdw, ΔN output from the deviation device 826 becomes negative, and the changeover switch 825 is switched to the contact b. At the same time, the correction value ΔN2 at that time is stored in the memory 823, and the function generator 824 determines that the correction value ΔN2 has passed the delay time t0 according to the correction value ΔN2 and the delay time t0 set by the adjustment signal S4. After that, a signal which becomes zero after being output is output as the correction value ΔN3,
It is output via 25.

If the target rotation speed Nx by the fuel lever 57 does not fluctuate during the delay time t0 and the pump pressure Pp continues to decrease, the rotation speed of the prime mover gradually decreases according to the output ΔN3 of the function generator 824. I do. On the other hand, during the delay time t0, the target rotation speed Nx by the fuel lever 57 does not fluctuate, but when the pump pressure Pp increases to exceed the up set pressure Pu, the output Δ from the function generator 820 is output.
Since N2 becomes larger than the previous value ΔNold, the deviation unit 82
6, the output ΔΔN becomes positive, and the changeover switch 825 switches to the contact a. As a result, the output ΔN3 from the function generator 824 is cut off, and ΔN2 is output as a rotation speed correction value.

In the above embodiment, the rotation speed correction value can be adjusted as follows. When the pump pressure Pp exceeds a predetermined value Pu, the function generator 820 starts to output the rotation speed correction value ΔN1 according to the increase characteristic NCup of FIG. 1, but the predetermined value Pu is arbitrarily adjusted by operating the rotation-up pressure setting dial 58b. it can. When the pump pressure Pp falls after exceeding the predetermined value Pu, the function generator 820 raises the pump pressure from the current value by (Pu−
The output correction value ΔN1 does not fluctuate until it decreases by the amount of Pd), and when the pump pressure decreases by more than (Pu−Pd) from the current value, the rotation speed correction value ΔN1 starts to be output according to the reduction characteristic NCdw of FIG. The predetermined value Pd can be arbitrarily adjusted by operating the rotation down pressure setting dial 58a. Rotation speed correction value ΔN1 output from function generator 820
Can be arbitrarily adjusted by operating the rotation-up amount setting dial 58c. The length of the delay time for reducing the once increased rotation speed correction value ΔN to zero can be adjusted by operating the delay time setting dial 58d.

By adjusting the rotation speed correction characteristic as described above, the rotation speed can be corrected according to the work mode and the preference of the operator. For example, in heavy excavation work, in order to obtain a larger amount of work, it is preferable that the number of rotations rises to a higher rotation region at high pressure. Therefore, as described above, the number of rotations is corrected by operating the rotation amount setting dial 58c. It is better to increase the value, and at the time of light excavation, it is better that the fluctuation of the rotation speed is small in consideration of the operation feeling and the fuel consumption, and the rotation speed correction value is reduced by operating the rotation up amount setting dial 58c.

The displacement capacity of the above-described variable displacement hydraulic pump is adjusted according to a predetermined pressure-flow rate curve, that is, a PQ curve, and the flow rate decreases as the pump pressure increases. In a normal excavation operation in which the displacement volume is controlled by such a PQ curve, it is better to increase the rotation speed in a region where the pressure is high and the flow rate is insufficient to some extent. On the other hand, in the leveling operation, in order to improve the operation feeling, it is better to increase the number of revolutions at a higher pressure than during normal excavation. Therefore, by operating the rotation-up pressure setting dial 58b, the predetermined value Pu is set low during excavation, and the predetermined value Pu is set high during leveling work. Furthermore, in the case of a suspended load operation, from the viewpoint of safety, it is better not to increase the number of rotations even if the pump pressure is increased. In this case, the predetermined value Pu
Is set to a very large value, or the selection switch 89 is opened.

In the excavation work, when the pump pressure becomes low after the rotation speed is increased, it is preferable to lower the increased rotation speed correction value to some extent slowly with a delay time because the rotation speed does not frequently increase and decrease. However, if the delay time until the rotation speed correction value becomes zero is set uniformly, some operators may feel that the operation feeling is bad. In this case, the delay time setting dial 58
Adjust the delay time as desired with d.

The adjustment dials 58a to 58c may be configured as shown in FIG. In FIG. 7, reference numeral 80 denotes a mode dial. The dial 80 is rotated to select one of the first to fifth modes. The mode dial 80 is connected to the four function generators 821a to 821d shown in FIG. 1, and a signal according to the selected mode is input to each function generator.

The first mode is the heavy work 1 mode, in which the rotation speed increase is started from a relatively low pressure, and the increase rotation speed correction value is large. The second mode is a heavy work second mode in which the increase in the number of revolutions is started from a relatively high pressure, and the increased number of revolutions correction value is large. The third mode is a normal operation mode in which the rotation speed is increased from an average pressure, and the increased rotation speed correction value is also an average value. The fourth mode is a light operation mode in which the rotation speed increase is started from a relatively low pressure, but the increase rotation speed correction value is small. The fifth mode is a leveling operation or a suspended load operation mode, and does not correct the increase in the number of rotations.

Table 1 shows the output signals in each mode.

[Table 1]

In the structure of the above embodiment, the hydraulic motor 4 and the working hydraulic cylinder 21 serve as hydraulic actuators, the fuel lever 57a serves as operating means, the target speed calculating section 81 serves as target speed setting means, and the speed correcting means. Value calculation unit 82
Denotes a rotation speed correction unit, the pulse motor 28 and the servo control unit 88 operate as a motor control unit, the pressure sensor 52 operates as a detection unit, the adjustment dials 58 a to 58 c and the function generator 821.
a to 821d constitute the adjusting means.

In the above description, the load on the hydraulic actuator is detected based on the pump pressure. However, the load on the actuator can be detected based on the pressure of the hydraulic actuator and the deviation between the actual engine speed and the target speed. In the above description, an example in which the engine target rotation speed is set according to the operation amount of the fuel lever has been described. However, the operation means is not limited to the fuel lever. For example, the engine target rotation speed is set according to the travel pedal operation amount. The present invention can also be applied to an object. Also, an engine target speed is set by an up / down switch, or a heavy load switch, a light load switch, and an idle switch are provided, and when each switch is operated, the engine target speed is set to a predetermined target value. You may do it. Further, the present invention can be similarly applied to hydraulic construction machines other than hydraulic excavators. Furthermore, the load sensing hydraulic drive control device has been described, but the present invention is not limited to this control method.

[0042]

As described above, according to the present invention, when increasing the number of rotations of the prime mover according to the load, the rotation number correction characteristic can be adjusted according to the work form and the preference of the operator. It is possible to provide a hydraulic construction machine with high operability.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating details of a rotation speed correction value calculation unit according to an embodiment.

FIG. 2 is a diagram illustrating an entire configuration of a drive control device of the hydraulic construction machine.

FIG. 3 is a diagram showing a pilot operation circuit of FIG. 2;

FIG. 4 is a block diagram of a pump control circuit unit.

FIG. 5 is a block diagram of a rotation speed control unit.

FIG. 6 is a flowchart illustrating a procedure of engine speed control.

FIG. 7 is a diagram showing a modification of the adjustment dial.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Variable displacement hydraulic pump 2 Traveling control valve 4 Traveling hydraulic motor 6 Pilot valve 6a Traveling pedal 8 Forward / reverse switching valve 20 Working control valve 21 Working cylinder 27 Engine (motor) 28 Pulse motor 40 Tilt control device 50 Controller Reference Signs List 51 tilt angle sensor 52 pressure sensor 53 rotation speed sensor 54 differential pressure sensor 55 potentiometer 57 rotation speed setting device 57a fuel lever 58a rotation down pressure setting dial 58b rotation up pressure setting dial 58c rotation up amount setting dial 58d delay time Setting dial 60 first control circuit unit 61 LS control unit 62 torque control unit 63 selection unit 64 servo control unit 80 second control circuit unit 81 target rotation speed calculation unit 82 rotation speed correction value calculation unit 820, 824 function Generator 822 Multiplier 823,827 Mori 826 Deflector

Claims (4)

(57) [Claims] 1. A variable displacement hydraulic pump driven by a prime mover, a hydraulic actuator driven by oil discharged from the hydraulic pump, detection means for detecting a load on the hydraulic actuator, and operation of an operation means. Target speed setting means for setting a target speed of the prime mover,
Based on the detected load of the hydraulic actuator,
A motor rotation speed control device for a hydraulic construction machine, comprising: a rotation speed correction unit that corrects the set target rotation speed; and a motor control unit that controls the motor to be the corrected target rotation speed. An engine speed control device for a hydraulic construction machine, comprising an adjusting means for adjusting a correction characteristic of the speed by the speed correcting means. 2. The control device according to claim 1, wherein said adjusting means adjusts a load for starting correction of the rotational speed. 3. The control device according to claim 1, wherein said adjusting means adjusts a magnitude of a rotational speed correction value with respect to a load. 4. The control device according to claim 1, wherein the rotation speed correction unit includes a gradual reduction unit that gradually reduces the rotation speed correction value to be zero after a set delay time has elapsed. A motor rotation speed control device for a hydraulic construction machine, wherein a delay time is adjusted.