JP2002295408A - Hydraulic drive control device - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To provide a hydraulic drive control device capable of automatically obtaining an optimum output characteristic of a variable hydraulic pump according to work contents, thereby reducing fuel consumption. SOLUTION: Operation levers 16 and 17 operated by an operator, specific operation state instructing means 19 for detecting a specific operation state of a working machine by the operation levers 16 and 17 and transmitting a detection signal to a controller 8; 20,2
The controller 8 has variable displacement hydraulic pumps 2, 3 according to a signal from the specific operation state instructing means.
Has a maximum value setting means for setting the maximum value of the input torque to a predetermined value.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic drive control device for controlling a hydraulic drive system of a hydraulic shovel, for example.

[0002]

2. Description of the Related Art Conventionally, in a construction machine such as a hydraulic excavator, for example, 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 are used. Various working machines such as a boom, an arm, and a bucket are driven by pressure oil discharged from the variable displacement hydraulic pump. Here, a control device for controlling the discharge oil amount of the variable displacement hydraulic pump (variable hydraulic pump) includes a hydraulic circuit for supplying pressure oil to a servo valve for adjusting a swash plate angle of the variable hydraulic pump. A control valve, wherein the control valve is adjusted in accordance with 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.

In this control device, since the input torque of the variable hydraulic pump becomes a constant value, the maximum value of the input torque is changed to the torque at the rated point of the maximum set output state of the engine at the set engine speed. Is set to a value commensurate with. Then, in the actual work, when a large power is required, for example, in heavy excavation, the target rotation speed of the engine is set to the maximum, and the input torque limit value of the variable hydraulic pump is set at the rated output of the engine. When the output torque of the engine is almost at its limit and the input torque of the variable hydraulic pump is increasing, the input torque of the variable hydraulic pump is set to the actual engine speed and the target engine speed. It is controlled to decrease as the deviation from the number increases. Further, in the case of work requiring relatively small power, the target rotation speed of the engine is set to be low, and the variable hydraulic pump is used with reduced absorption power.

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. The input torque limit 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 to perform the work. As a result, the maximum supply amount of the pressurized oil to be supplied is reduced, and the maximum speed of the actuator is reduced, so that the working efficiency is reduced.

[0005] To deal with such problems,
The operator can select and specify the maximum value of the input torque of the variable hydraulic pump corresponding to the output torque of the engine from among a plurality of values according to the work mode. There is a hydraulic pump drive system control device that sets a target displacement of a discharge amount control means corresponding to a selected input torque maximum value from a detected discharge pressure of a variable hydraulic pump (Japanese Patent Publication No. 4-59457). Gazette).

[0006]

However, in the control device described in Japanese Patent Publication No. 4-59457, when an operator selects a certain work mode, the input of the variable hydraulic pump is made corresponding to the work mode. Since the torque maximum value is set to a predetermined value, for example, in the heavy excavation work mode, after the earth and sand accumulated in the bucket by the excavation work are discharged, the operation of lowering while turning the boom again, so-called “ When an operation called "down swing" is performed, a downward force due to its own weight falls acts on the bucket, which causes the variable hydraulic pump to perform extra work, and wasteful fuel consumption is made. This is a factor that deteriorates fuel efficiency. In short, in this conventional device, once the operator sets the work mode, the maximum input torque of the variable hydraulic pump does not change even if the work is changed in the work mode. Is caused.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and it is possible to automatically obtain an optimum output characteristic of a variable hydraulic pump according to work contents, thereby reducing fuel consumption. It is an object of the present invention to provide a hydraulic drive control device capable of performing the following.

[0008]

In order to achieve the above object, a hydraulic drive control device according to the present invention comprises a variable displacement hydraulic pump driven by an engine, and a pressure discharged from the hydraulic pump. A work machine driven by oil, discharge amount control means for controlling the discharge oil amount of the hydraulic pump, and the discharge amount so that the input torque of the hydraulic pump becomes substantially constant according to the discharge pressure of the hydraulic pump. In a hydraulic drive control device including a controller for controlling a control means, an operation lever operated by an operator, and a specific operation of detecting a specific operation state of the work implement by the operation lever and transmitting a detection signal to the controller State controller, and the controller comprises:
There is provided a maximum value setting means for setting a maximum value of the input torque of the hydraulic pump to a predetermined value in accordance with a signal from the specific operation state instruction means (first invention).

According to the present invention, a specific operation state of the work implement by the operation lever operated by the operator is detected, and when the operation lever, in other words, the work implement is in the specific operation state, the input torque of the hydraulic pump is detected. Is set to a predetermined value in accordance with the operation state. Therefore, the maximum value of the input torque of the hydraulic pump is set to an optimum value in accordance with the work content of the work machine, so that unnecessary fuel consumption can be eliminated and fuel efficiency can be reduced.

[0010] In the present invention, further, a work mode selecting means for selecting a desired work mode from a plurality of work modes performed by the work machine, and an engine according to the work mode selected by the work mode selecting means. It is preferable that an output torque setting means for setting the output torque characteristic is provided (second invention). By doing so, according to the work mode selected by the work mode selection means,
The engine output torque characteristics suitable for work can be obtained, and the output torque characteristics of this engine
The maximum value of the input torque of the hydraulic pump according to the work content is obtained, so not only the type of work, but also when the work content is changed within the same work, the optimal pump maximum torque that matches the work content Value can be obtained.

In each of the above inventions, it is preferable that the working machine is a boom of a hydraulic shovel, and the specific operation state is a combined operation state of a lowering operation and a turning operation of the boom (third invention). As described above, in the combined operation state of the boom lowering operation and the turning operation (down turning state), the bucket is lowered by its own weight, so that even if the pump horsepower is reduced, there is no problem in the operation, and furthermore, uncomfortable feeling. The fuel consumption can be reduced by lowering the input torque of the hydraulic pump. In this down turning state,
By setting the maximum value of the input torque as described above, there is also an advantage that the movement of the boom is performed smoothly.

[0012]

Next, a specific embodiment of a hydraulic drive control device according to the present invention will be described with reference to 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.

In this embodiment, an engine 1 is provided, and a first engine driven by the engine 1 is provided.
The variable displacement hydraulic pump 2 and the second variable displacement hydraulic pump 3 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 configured to be driven by a governor drive motor 6. The driving position of the fuel control lever 5a is detected by the potentiometer 7, and a detection signal is input to the controller 8. Further, a fuel dial 9 is provided for setting a 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. The actual rotation speed of the output shaft of the engine 1 is detected by a rotation speed sensor 10, and a detection signal thereof is also input to the controller 8.

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 supplied to an operation valve 11 (boom operation valve, arm operation valve, etc.).
Are supplied to a boom cylinder, an arm cylinder, a bucket cylinder, a traveling motor, a turning motor, and the like (not shown) to drive these working machines and the like. These variable displacement hydraulic pumps 2 and 3 are provided with servo valves 12 and 13
As a result, the tilt angles of the swash plates 2a and 3a of the hydraulic pumps 2 and 3 are changed, and the discharge oil amount per rotation is changed. Each of the servo valves 12 and 13 has a detector for detecting the tilt angle, and the tilt angle signal is input to the controller 8.

In the discharge oil passages of the respective variable displacement hydraulic pumps 2 and 3, hydraulic sensors 14 and 15 for detecting the discharge hydraulic pressure are provided, respectively, and the pressure signals detected by these hydraulic sensors 14 and 15 are supplied to a controller. 8 is input.

On the other hand, a turning / arm operating lever 16, a boom / bucket operating lever 17, and a traveling operating lever 18 are provided in the operator's cab to operate the work machine. These operating levers 16, 17, 18 are respectively provided. Are input to the controller 8 via the hydraulic switches 19, 20, and 21. A knob switch (power-up switch) 22 is attached to the turning / arm operation lever 16, and an operation signal of the knob switch 22 is also input to the controller 8.

Further, a monitor panel (work mode selecting means) 23 for selecting a work mode such as a heavy excavation mode, an excavation mode, a straightening mode, and a fine operation mode in the hydraulic excavator is provided. The mode selection signal is also input to the controller 8.

The controller 8 determines a predetermined signal based on a deviation signal between a throttle signal (a target speed signal) input from a fuel dial 9 and an actual speed signal of the engine 1 detected by a speed sensor 10. A voltage satisfying the functional relationship 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 a characteristic as shown in FIG.

As an example, assuming that the fuel dial 9 is set at the maximum position, the potentiometer 9a
The output signal from the _'is set to a size which indicates a maximum target engine speed N _S is the controller _8' maximum target engine speed N _S motor drive signal corresponding to 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 (Maximum horsepower point). Thus, the output horsepower of the engine 1 and the engine speed are automatically set.

In this embodiment, the monitor panel 23
When the work mode selected by are heavy digging mode, the governor 5 sets the regulation line L _A shown in FIG. 2, when the work mode selected is excavation mode, governor 5 setting the regulation line L _E shown in FIG.

In the controller 8, the turning /
Arm operating lever 16, boom / bucket operating lever 1
When a specific operation state of the working machine is detected based on the operation lever signal from the driving operation lever 7 and the traveling operation lever 18, the maximum value (limit value) of the input torque of the variable displacement hydraulic pumps 2, 3 is limited to a predetermined value. In other words, in other words, the control is performed such that the maximum value of the input torque of the variable displacement hydraulic pumps 2 and 3 is set to a value lower than the originally set input torque according to the pattern of the work machine.

Next, the specific contents of the control for setting the input torque limit value will be described with reference to the flowchart shown in FIG.

S1: It is determined whether or not the work mode selected by the monitor panel 23 is the heavy excavation mode. When the mode is the heavy excavation mode, the process proceeds to the next step S2, and when a mode other than the heavy excavation mode is selected, the process proceeds to another flow. Note that this other flow is substantially the same as the flow of steps S2 to S11 described below, and a detailed description thereof will be omitted.

S2: The knob switch (power-up switch) 22 attached to the swing / arm operation lever 16 is turned off.
It is determined whether N operations have been performed. When the knob switch 22 is ON, the process proceeds to the next step S3, and when the knob switch 22 is not ON, the process skips to step S5.

S3: If the knob switch 22 has been turned ON, then it is determined whether or not the turning operation is being performed independently, in other words, the turning operation and other working machine operations are performed in combination. Is determined. When the turning operation is not performed alone (YES), the process proceeds to the next step S4, and when the turning operation is performed alone (NO), the process skips to step S5.

S4: If the knob switch 22 is turned ON and the turning operation is not performed independently,
It is determined whether or not the operation levers 16 and 17 are in the neutral position, in other words, whether or not the work equipment such as the boom, the arm, and the bucket is moving. When the operation levers 16 and 17 are at the neutral position (NO), the process proceeds to the next step S5. On the other hand, 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 operated.
Is not at the neutral position, the process proceeds to step S8.

S5: If 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, the condition is satisfied. Then, 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.

S6: When it is determined in the previous step S5 that the vehicle is in a turning state, it is next determined whether or not the operation is a turning-only operation. If the result of this determination is that the vehicle is not turning alone, the flow proceeds to the next step S7, and if it is a turning only, the flow proceeds to step S9.

S7: Next, it is determined whether or not the boom is down. When the vehicle is in the boom lowered state, the process proceeds to step S10.

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, Since it is not necessary to perform control to limit the maximum value of the input torque of the variable displacement hydraulic pumps 2 and 3 to a predetermined value, the pump input torque limit value (topping torque value) is shown by "operation 1" in FIG. Value, in other words, the maximum torque value of the output torque characteristic of the engine 1.

S9: Since the turning operation is performed independently, the pump input torque limit value (topping torque value) is set to the value (medium value) indicated by "Work 2" in FIG.
Set to.

S10: In the combined operation 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 (the peaking torque value) in FIG. 3 ”is set to a lower value.

S11: When the operation is not the swing operation alone and is not in the boom lowering state, in other words, for example, a combined operation of a swing operation and a boom raising operation (a hoist swing), a combined operation of a swing operation and an arm dump operation, or Since the operation state is such as the combined operation of the turning operation and the bucket dump, the pump input torque limit value (topping torque value) is set to a slightly higher value shown in “operation 4” in FIG.

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 machine. Therefore, it is possible to easily perform an operation in which it is extremely difficult for the operator to operate the work implement by controlling the oil pressure by manual operation using the operation lever. In particular, in a so-called down swing operation state in which the boom lowering operation and the swing operation are performed in a combined manner, the bucket is lowered by its own weight. Fuel consumption can be reduced by reducing the input torque of the hydraulic pump. Further, during the down turning operation, the boom does not move unnaturally such as moving downward after moving in the horizontal direction, and can smoothly move by drawing a gentle curve toward the movement target point. There is also an effect.

Further, according to the present embodiment, when the work mode is changed, the work mode can be appropriately selected by the monitor panel 23, so that the engine output suitable for the work is always selected according to the selected work mode. The torque characteristic can be obtained, and the maximum value of the input torque of the hydraulic pump according to the work content can be obtained for the selected work mode.

In this embodiment, the description has been made centering on the combined operation of the turning operation and the boom lowering operation. However, other work contents, for example, the combined operation of the boom lowering and the arm excavation or the bucket excavation, and further, the arm dumping Alternatively, the pump input torque limit value can be individually set for a combined operation with a bucket dump or the like. Furthermore, not only the work content of the working machine, but also in a case where the traveling operation of the vehicle body and the work 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 illustrating a limit value of a pump input torque.

FIG. 3 is a flowchart illustrating a control processing procedure according to the embodiment;

[Explanation of symbols]

DESCRIPTION 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 Speed sensor 11 Operating valve 12, 13 Servo valve 14, Reference Signs List 15 Oil pressure sensor 16 Swivel / arm operation lever 17 Boom / bucket operation lever 19, 20, 21 Hydraulic switch (specific operation state indicating means) 22 Knob switch (specific operation state indicating means) 23 Monitor panel

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) F15B 11/02 F15B 11/02 C (72) Inventor Shinobu Kitayama 3-1-1 Ueno, Hirakata-shi, Osaka Shares (72) Inventor Shinji Maeda 3-25-1 Shinomiya, Hiratsuka-shi, Kanagawa Prefecture Incorporated Company Inside Komatsu Ltd. Shinomiya System Development Center (72) Inventor, Masahiko Hoshitani 3-25-1, Shinomiya, Hiratsuka-shi, Kanagawa F-term in Komatsu Ltd.'s Shinnomiya System Development Center (reference)

Claims (3)

[Claims] 1. A variable displacement hydraulic pump driven by an engine, a working 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, In a hydraulic drive control device including a controller that controls the discharge amount control means so that an input torque of the hydraulic pump becomes substantially constant according to a discharge pressure of the hydraulic pump, an operation lever operated by an operator; Specific operation state instructing means for detecting a specific operation state of the working machine by a lever and transmitting a detection signal to the controller, wherein the controller responds to a signal from the specific operation state instructing means, A hydraulic drive control device comprising a maximum value setting means for setting a maximum value of an input torque of a hydraulic pump to a predetermined value. 2. A work mode selection means for selecting a desired work mode from a plurality of work modes performed by the work machine, and an output of the engine according to the work mode selected by the work mode selection means. The hydraulic drive control device according to claim 1, further comprising an output torque setting means for setting a torque characteristic. 3. The hydraulic drive control device according to claim 1, wherein the working machine is a boom of a hydraulic shovel, and the specific operation state is a combined operation state of a lowering operation and a turning operation of the boom. .