JP4731033B2 - Hydraulic drive control device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a hydraulic drive control device that controls, for example, a hydraulic drive system of a hydraulic excavator.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, a construction machine such as a hydraulic excavator is provided with an engine (internal combustion engine) controlled by adjusting a fuel injection amount by a fuel injection pump and a variable displacement hydraulic pump driven by the engine. Various working machines such as a boom, an arm and a bucket are driven by pressure oil discharged from the mold hydraulic pump. Here, as a control device that controls the amount of oil discharged from the variable displacement hydraulic pump (variable hydraulic pump), a hydraulic circuit that supplies pressure oil to a servo valve that adjusts the swash plate angle of the variable hydraulic pump is used. A control valve is provided, and this control valve is adjusted according to the discharge pressure of the variable hydraulic pump to control the discharge amount of the variable hydraulic pump, thereby controlling the input torque of the variable hydraulic pump to be constant. It has been known.
[0003]
In this control device, since the input torque of the variable hydraulic pump becomes a constant value, the maximum value of this input torque is a value commensurate with the rated point torque of the maximum set output state of the engine at the set engine speed. Has been set to. In actual work, for example, when heavy power is required, such as heavy excavation, the target engine speed is set to the maximum, and the input torque limit value of the variable hydraulic pump is set to the value at the rated output of the engine. When the output torque of the engine almost reaches the limit and the input torque of the variable hydraulic pump tends to increase, the input torque of the variable hydraulic pump is set to the actual engine speed and the target speed. It is controlled so as to decrease as the deviation from the number increases. Further, in the case of work that requires relatively small power, the target rotational speed of the engine is set to be low, and the absorption power of the variable hydraulic pump is reduced.
[0004]
However, in such a control device, when the target engine speed is set, the input torque limit value of the variable hydraulic pump is determined to be one value. Therefore, depending on the work contents or the work environment, the input torque limit value is determined. The value is not appropriate and may cause various inconveniences. For example, when working with low noise in the work environment, it is necessary to lower the engine speed, but when the engine speed is reduced in this way, the actuator is supplied proportionally. As a result, the maximum supply amount of the pressurized oil is lowered, the maximum speed of the actuator is lowered, and the working efficiency is lowered.
[0005]
As a countermeasure against such problems, the maximum value of the variable hydraulic pump input torque corresponding to the engine output torque can be selected and designated by the operator from a plurality of values according to the work mode. The hydraulic pump drive system that sets the target displacement of the discharge amount control means corresponding to the selected maximum input torque value from the selected maximum value of the input torque and the detected discharge pressure of the variable hydraulic pump There is a control device (see Japanese Patent Publication No. 4-59457).
[0006]
[Problems to be solved by the invention]
However, in the control device described in Japanese Patent Publication No. 4-59457, when an operator selects a specific work mode, the maximum input torque value of the variable hydraulic pump is set to a predetermined value corresponding to the work mode. Therefore, for example, in the heavy excavation work mode, after discharging the earth and sand accumulated in the bucket by excavation work, the operation of lowering the boom while turning it again, the so-called "down turning" If this is done, a downward force is applied to the bucket due to its own weight drop, which causes the variable hydraulic pump to do extra work, causing unnecessary fuel consumption and a deterioration in fuel efficiency. End up. In short, in this conventional apparatus, once the work mode is set by the operator, the maximum input torque value of the variable hydraulic pump does not change even if the work content changes in the work mode. There is a problem that it will occur.
[0007]
The present invention has been made in view of such problems, and it is possible to automatically obtain the optimum output characteristics of the variable hydraulic pump in accordance with the work content, thereby reducing the fuel consumption. An object of the present invention is to provide a drive control device.
[0008]
[Means for solving the problems and actions / effects]
In order to achieve the above object, a hydraulic drive control device according to the first invention comprises:
A variable displacement hydraulic pump driven by an engine; a work machine driven by pressure oil discharged from the hydraulic pump; a discharge amount control means for controlling a discharge oil amount of the hydraulic pump; and a discharge of the hydraulic pump In a hydraulic drive control device comprising a controller for controlling the discharge amount control means so that the input torque of the hydraulic pump becomes substantially constant according to pressure,
An operation lever operated by an operator, a power up switch attached to the operation lever, and a heavy excavation mode, an excavation mode, a correction mode, and a fine operation mode among a plurality of operation modes performed by the working machine A work mode selection means for selecting a desired work mode, output torque setting means for setting an output torque characteristic of the engine in accordance with the work mode selected by the work mode selection means, and the work lever by the operation lever. Specific operation state instruction means for detecting a specific operation state and transmitting a detection signal to the controller, wherein the controller determines the input torque of the hydraulic pump according to a signal from the specific operation state instruction means. has a maximum value setting means for setting a maximum value to a predetermined value, said maximum value setting means, wherein the specific operation state, the hydraulic pressure When a composite work with the turning operation of the boom lowering operation and the upper revolving body of Yoberu, characterized by setting the maximum value of the input torque of the hydraulic pump as compared with the pivoting alone operation of the upper rotating body to a lower value It is what .
[0009]
According to the present invention, a specific operation state of the work machine by the operation lever operated by the operator is detected, and the specific operation state of the work machine by the operation lever is a boom lowering operation of the hydraulic excavator as the work machine. When the combined operation with the swing operation of the upper swing body, that is, in the so-called down swing operation state, the maximum value of the input torque of the hydraulic pump is set to a lower value than the swing single operation of the upper swing body . In the combined operation state of the boom lowering operation and the turning operation (down turning state), since the bucket is lowered by its own weight, there is no problem in operation even if the pump horsepower is reduced, and there is no sense of incongruity. The fuel consumption can be reduced by reducing the input torque. In addition, in this down turning state, setting the maximum value of the input torque as described above also has an advantage that the boom moves smoothly.
[0010]
The hydraulic drive control device according to the second invention is
A variable displacement hydraulic pump driven by an engine; a work machine driven by pressure oil discharged from the hydraulic pump; a discharge amount control means for controlling a discharge oil amount of the hydraulic pump; and a discharge of the hydraulic pump In a hydraulic drive control device comprising a controller for controlling the discharge amount control means so that the input torque of the hydraulic pump becomes substantially constant according to pressure,
An operation lever operated by an operator, a power up switch attached to the operation lever, and a heavy excavation mode, an excavation mode, a correction mode, and a fine operation mode among a plurality of operation modes performed by the working machine A work mode selection means for selecting a desired work mode, output torque setting means for setting an output torque characteristic of the engine in accordance with the work mode selected by the work mode selection means, and the work lever by the operation lever. Specific operation state instruction means for detecting a specific operation state and transmitting a detection signal to the controller, wherein the controller determines the input torque of the hydraulic pump according to a signal from the specific operation state instruction means. A maximum value setting means for setting a maximum value to a predetermined value, the maximum value setting means, wherein the specific operation state is hydraulic pressure The hydraulic pump is more complex than the single swing operation of the upper swing body when it is a combined work of any of the boom lift operation of the shovel, the arm dump operation, the bucket dump operation and the upper swing body swing operation. The maximum value of the input torque is set to a higher value.
[0011]
According to the present invention, the maximum value of the input torque of the hydraulic pump in a combined work of any one of the boom raising operation, the arm dumping operation, and the bucket dumping operation of the hydraulic excavator and the turning operation of the upper swing body Is set to a higher value, it is possible to obtain an optimum pump maximum torque value suitable for the work content.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Next, specific embodiments of the hydraulic drive control apparatus according to the present invention will be described with reference to the drawings.
[0013]
FIG. 1 is a system configuration diagram of a hydraulic drive control device according to an embodiment of the present invention applied to a hydraulic excavator.
[0014]
In the present embodiment, an engine 1 is provided, and a first variable displacement hydraulic pump 2 and a second variable displacement hydraulic pump 3 driven by the engine 1 are provided. The engine 1 is provided with a fuel injection pump 4 and a governor 5, and a fuel control lever 5 a of the governor 5 is driven by a governor drive motor 6. The drive position of the fuel control lever 5 a is detected by the potentiometer 7, and the detection signal is input to the controller 8. Further, a fuel dial 9 is provided for setting the throttle amount of the engine 1, and a throttle signal from a potentiometer 9 a attached to the fuel dial 9 is input to the controller 8. Further, the actual rotational speed of the output shaft of the engine 1 is detected by the rotational speed sensor 10, and the detection signal is also input to the controller 8.
[0015]
The discharge pressure oil of the first variable displacement hydraulic pump 2 and the discharge pressure oil of the second variable displacement hydraulic pump 3 are not shown via the operation valve 11 (boom operation valve, arm operation valve, etc.). These are supplied to a boom cylinder, an arm cylinder, a bucket cylinder, a travel motor, a turning motor, etc., and drive these working machines. In these variable displacement hydraulic pumps 2 and 3, the tilting angles of the swash plates 2a and 3a of the hydraulic pumps 2 and 3 are changed by the servo valves 12 and 13, respectively, and the amount of discharged oil per one rotation is changed. The servo valves 12 and 13 are provided with a detector for detecting the tilt angle, and the tilt angle signal is input to the controller 8.
[0016]
Oil pressure sensors 14 and 15 for detecting the discharge oil pressure are provided in the discharge oil passages of the variable displacement hydraulic pumps 2 and 3, respectively, and pressure signals detected by the oil pressure sensors 14 and 15 are input to the controller 8. Is done.
[0017]
On the other hand, a swivel / arm operation lever 16, a boom / bucket operation lever 17 and a travel operation lever 18 are provided in the cab to operate the work implement, and the operations of these operation levers 16, 17, 18 are provided. The lever signal is input to the controller 8 via the hydraulic switches 19, 20 and 21. The turning / arm operation lever 16 is provided with a knob switch (power up switch) 22, and an operation signal of the knob switch 22 is also input to the controller 8.
[0018]
Further, a monitor panel (work mode selection means) 23 for selecting a work mode such as a heavy excavation mode, excavation mode, correction mode, and fine operation mode in the hydraulic excavator is provided, and a work mode selection signal from the monitor panel 23 is provided. Is also input to the controller 8.
[0019]
The controller 8 has a predetermined functional relationship based on a deviation signal between the throttle signal (target speed signal) input from the fuel dial 9 and the actual speed signal of the engine 1 detected by the speed sensor 10. A satisfying voltage is generated as a drive signal, and the governor drive motor 6 is driven based on the drive signal. Further, the governor 5 controls the output torque of the engine 1 according to characteristics as shown in FIG.
[0020]
As an example, assuming that the fuel dial 9 is set at the maximum position, the output signal from the potentiometer 9a is set to a magnitude indicating the maximum target engine speed N _S ′. A motor drive signal corresponding to the target engine speed N _S ′ is applied to the governor drive motor 6. Thus the governor driving motor 6 operates the fuel control lever 5a to be set is the maximum speed regulation line L _S, synthetic absorbable torque and the P _S point of the output torque and variable displacement hydraulic pumps 2 and 3 of the engine 1 Matching will be done at (maximum horsepower point). Thus, the output horsepower and engine speed of the engine 1 are automatically set.
[0021]
In the present embodiment, when the work mode selected by the monitor panel 23 is heavy excavation mode, the governor 5 sets the regulation line L _A shown in FIG. 2, the selected working mode excavation mode If it is, the governor 5 sets a regulation line L _E shown in FIG.
[0022]
In the controller 8, when a specific operation state of the work implement is detected by operation lever signals from the turning / arm operation lever 16, the boom / bucket operation lever 17, and the travel operation lever 18, the variable displacement hydraulic pump In other words, the maximum value of the input torque of the variable displacement hydraulic pumps 2 and 3 is originally set so as to limit the maximum value (limit value) of the input torques 2 and 3 to a predetermined value. Control is executed so as to set a value lower than the input torque.
[0023]
Next, specific contents of the control for setting the input torque limit value will be described with reference to the flowchart shown in FIG.
[0024]
S1: It is determined whether or not the work mode selected by the monitor panel 23 is the heavy excavation mode. If it is in the heavy excavation mode, the process proceeds to the next step S2, and if a mode other than the heavy excavation mode is selected, the process proceeds to another flow. Since this other flow is almost the same as the flow of steps S2 to S11 described below, detailed description thereof will be omitted.
[0025]
S2: It is determined whether or not the knob switch (power up switch) 22 attached to the turning / arm operation lever 16 is turned on. When the knob switch 22 is turned on, the process proceeds to the next step S3. When the knob switch 22 is not turned on, the process skips to step S5.
[0026]
S3: When the knob switch 22 is turned on, whether or not the next turning operation is performed independently, in other words, whether or not the turning operation and other work machine operations are performed in combination. Determine. When the turning operation is not performed alone (YES), the process proceeds to the next step S4, and when the turning operation is performed independently (in the case of NO), the process skips to step S5.
[0027]
S4: When the knob switch 22 is turned ON and the turning operation is not performed independently, whether or not the operation levers 16 and 17 are in the neutral position, in other words, a working machine such as a boom, an arm, and a bucket Determine if you are in a moving state. When the operation levers 16 and 17 are in the neutral position (NO), the process proceeds to the next step S5. On the other hand, if the knob switch (power up switch) 22 is turned ON, the turning operation is not performed independently, and the operation levers 16 and 17 are not in the neutral position, the process proceeds to step S8.
[0028]
S5: If any of the conditions that the knob switch 22 is not turned ON, the turning operation is performed alone, or the operation levers 16 and 17 are in the neutral position is satisfied, It is determined whether or not the vehicle is in a turning state. When it is determined that the vehicle is in the turning state, the process proceeds to the next step S6, and when it is determined that the vehicle is not in the turning state, the process proceeds to step S8.
[0029]
S6: If it is determined in the previous step S5 that the vehicle is in a turning state, it is next determined whether or not the vehicle is in a turning operation alone. If the result of this determination is that the vehicle is not turning alone, the operation proceeds to the next step S7, and if the vehicle is turning alone, the operation proceeds to step S9.
[0030]
S7: Next, it is determined whether or not the boom is lowered. When the boom is lowered, the process proceeds to step S10. When the boom is not lowered, the process proceeds to step S11.
[0031]
S8: Since the knob switch (power up switch) 22 is turned ON, the turning operation is not performed independently, and the operation levers 16 and 17 are not in the neutral position, the above-described variable capacity type Since it is not necessary to perform control to limit the maximum value of the input torque of the hydraulic pumps 2 and 3 to a predetermined value, the pump input torque limit value (the peak torque value) is the value indicated by “operation 1” in FIG. For example, the maximum torque value of the output torque characteristic of the engine 1 is set.
[0032]
S9: Since the turning operation is performed independently, the pump input torque limit value (heading torque value) is set to the value (medium value) indicated by “operation 2” in FIG.
[0033]
S10: In the combined work state of the turning operation and the boom lowering operation, in other words, in the so-called down turning operation state, the pump input torque limit value (heading torque value) is set to “operation 3” in FIG. Set to a lower value.
[0034]
S11: When the swing operation is not performed alone and the boom is not lowered, in other words, for example, a combined operation of the swing operation and the boom raising operation (hoist swing), a combined operation of the swing operation and the arm dump operation, or the swing operation Since this is a state of operation such as a combined operation with a bucket dump, the pump input torque limit value (the peak torque value) is set to a slightly higher value as indicated by “operation 4” in FIG.
[0035]
As described above, according to the present embodiment, the input torque limit value of the hydraulic pump can be automatically set to an optimum value according to the work content of the work implement. Therefore, it is possible to easily perform an operation that is extremely difficult for the operator to control the hydraulic pressure by manual operation with the operation lever and to perform the work machine operation. In particular, in the so-called down turning operation state in which the boom lowering operation and the turning operation are combined, the bucket is lowered by its own weight, so there is no trouble in operation even if the pump horsepower is reduced, and there is no sense of incongruity. It is possible to reduce the fuel consumption by reducing the input torque of the hydraulic pump. Further, at the time of this down turning operation, the boom does not move unnaturally such as moving downward after moving in the horizontal direction, and it can be smoothly moved while drawing a gentle curve toward the moving target point. There is also an effect.
[0036]
Furthermore, according to the present embodiment, when the work mode is changed, the work mode can be appropriately selected by the monitor panel 23. Therefore, an engine output torque characteristic that is always suitable for work can be obtained according to the selected work mode. In addition, the maximum value of the input torque of the hydraulic pump corresponding to the work content can be obtained for the selected work mode.
[0037]
In the present embodiment, the description is centered on the combined operation of the turning operation and the boom lowering operation, but other work contents, for example, the combined operation of the boom lowering and the arm excavation or bucket excavation, and further the arm dump or bucket dump The pump input torque limit value can also be set individually for combined operations with the above. Furthermore, not only the work content of the work machine but also the case where the traveling operation and work of the vehicle main body are combined, the pump input torque limit value can be individually set for each.
[Brief description of the drawings]
FIG. 1 is a system configuration diagram of a hydraulic drive control device according to an embodiment of the present invention applied to a hydraulic excavator.
FIG. 2 is a graph for explaining a limit value of pump input torque.
FIG. 3 is a flowchart illustrating a control processing procedure according to the present embodiment;
[Explanation of symbols]
1 Engine 2, 3 Variable displacement hydraulic pump 4 Fuel injection pump 5 Governor 6 Governor drive motor 8 Controller (maximum value setting means, output torque setting means)
9 Fuel dial 10 Rotational speed sensor 11 Operation valve 12, 13 Servo valve 14, 15 Hydraulic sensor 16 Swing / arm operation lever 17 Boom / bucket operation lever 19, 20, 21 Hydraulic switch (specific operation state instruction means)
22 Knob switch (specific operation state indication means)
23 Monitor panel

Claims (2)

A variable displacement hydraulic pump driven by an engine; a work machine driven by pressure oil discharged from the hydraulic pump; a discharge amount control means for controlling a discharge oil amount of the hydraulic pump; and a discharge of the hydraulic pump In a hydraulic drive control device comprising a controller for controlling the discharge amount control means so that the input torque of the hydraulic pump becomes substantially constant according to pressure,
An operation lever operated by an operator, a power up switch attached to the operation lever, and a heavy excavation mode, an excavation mode, a correction mode, and a fine operation mode among a plurality of operation modes performed by the working machine A work mode selection means for selecting a desired work mode, output torque setting means for setting an output torque characteristic of the engine in accordance with the work mode selected by the work mode selection means, and the work lever by the operation lever. Specific operation state instruction means for detecting a specific operation state and transmitting a detection signal to the controller, wherein the controller determines the input torque of the hydraulic pump according to a signal from the specific operation state instruction means. has a maximum value setting means for setting a maximum value to a predetermined value, said maximum value setting means, wherein the specific operation state, the hydraulic pressure When a composite work with the turning operation of the boom lowering operation and the upper revolving body of Yoberu, characterized by setting the maximum value of the input torque of the hydraulic pump as compared with the pivoting alone operation of the upper rotating body to a lower value Hydraulic drive control device. A variable displacement hydraulic pump driven by an engine; a work machine driven by pressure oil discharged from the hydraulic pump; a discharge amount control means for controlling a discharge oil amount of the hydraulic pump; and a discharge of the hydraulic pump In a hydraulic drive control device comprising a controller for controlling the discharge amount control means so that the input torque of the hydraulic pump becomes substantially constant according to pressure,
An operation lever operated by an operator, a power up switch attached to the operation lever, and a heavy excavation mode, an excavation mode, a correction mode, and a fine operation mode among a plurality of operation modes performed by the working machine A work mode selection means for selecting a desired work mode, output torque setting means for setting an output torque characteristic of the engine in accordance with the work mode selected by the work mode selection means, and the work lever by the operation lever. Specific operation state instruction means for detecting a specific operation state and transmitting a detection signal to the controller, wherein the controller determines the input torque of the hydraulic pump according to a signal from the specific operation state instruction means. A maximum value setting means for setting a maximum value to a predetermined value, the maximum value setting means, wherein the specific operation state is hydraulic pressure The hydraulic pump is more complex than the single swing operation of the upper swing body when it is a combined work of any of the boom lift operation of the shovel, the arm dump operation, the bucket dump operation and the upper swing body swing operation. A hydraulic drive control device characterized in that the maximum value of the input torque is set to a higher value .

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