JPH1088621A - Hydraulic control mechanism of excavating machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To facilitate the output control of an engine, by selecting an engine output characteristic corresponding to a work mode by a mode-selection switch, in an excavating machine mounting the engine provided with an electronic governer structure. SOLUTION: When one of a light load mode, a usual mode, and a heavy load mode is selected by a mode-selection switch S in accordance with a working mode, in a construction machine like back hoe, an isochronous control and a reverse droop control are combined and an engine output characteristic adaptable for the mode is set. And further, the pressure-flow rate characteristic of a variable quantity type hydraulic pump in a light load mode is shifted down against an usual mode and the characteristic of the pump in a heavy load mode is shifted up against it. In the case of the light load mode and the usual load mode, the characteristic is shifted up also by a traveling two-speed signal and an increased speed traveling mode is added. Accordingly, the engine output control is made easy and an appropriate delivery pressure and flow rate of the hydraulic oil can be supplied.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pressure-flow control diagram of a hydraulic pump for a working machine in an excavating machine equipped with an engine having an electronic governor mechanism.

[0002]

2. Description of the Related Art Conventionally, a technique for controlling a pressure-flow rate control diagram of a hydraulic pump for driving a working machine of an excavating machine has been known. For example, JP-A-62-1603
No. 33, JP-B-62-38498, and JP-A-3-147936.

[0003]

SUMMARY OF THE INVENTION The present invention relates to an excavator equipped with an engine equipped with an electronic governor mechanism, in which the output characteristic curve of the engine is varied according to the operation mode, and the "light load mode" and the "normal Mode and heavy load mode, the pressure-flow control diagram is prepared in accordance with each of the above-mentioned modes. By setting a pressure-flow rate control diagram of the pump, the output of the engine can be easily controlled. Further, by selecting a mode of a pressure-flow rate control diagram according to a work mode, work performance is improved and energy is saved. Further, since the control of the swash plate of the hydraulic pump is performed by the external bilot pressure PE / PF, the control can be easily changed or adjusted.

[0004] The output characteristic curves of the engine are three types of "light load mode", "normal mode" and "heavy load mode".
Although the mode is the mode, the pressure-flow rate control diagram of the hydraulic pump shows “light load mode”, “light load mode + increased traveling”, “normal mode”, “normal mode + increased traveling”, and “heavy load mode”. Load mode ”. In the case of “light load mode + speed-up traveling” and “normal mode + speed-up traveling”, the main relief pressure of the control valve CV is
The pressure is increased by about 20%. Further, the pressure-flow rate control diagram of the hydraulic pump is shifted up by about 10%.
This makes it possible to supply the flow rate and pressure of the pressurized oil necessary for speed-up traveling.

[0005] The pressure-flow control diagram in the "light load mode" is a configuration in which the pressure-flow control diagram in the "normal mode" is shifted down in the parallel direction. The pressure-flow control diagram of the “heavy load mode” is a configuration in which the pressure-flow control diagram of the “normal mode” is shifted up in the parallel direction, and the pressure-flow diagram of the “normal mode + speed increasing” is obtained.
It has the same configuration as the flow control diagram.

[0006]

The problem to be solved by the present invention is as described above. Next, means for solving the problem will be described. According to the first aspect, in the configuration in which the variable displacement pump for performing the constant horsepower control is mounted on the excavator, the output characteristics of the engine are different from those of the "light load mode", the "normal mode", and the "heavy load mode". And a pressure-flow control diagram of a hydraulic pump that matches the three modes is set.

According to a second aspect of the present invention, in the configuration in which a variable displacement pump for performing constant horsepower control is mounted on the excavator,
Engine output characteristics different from "light load mode", "normal mode" and "heavy load mode" are provided, and pressure-flow control diagrams of hydraulic pumps corresponding to the three modes are set, respectively. The mode is a "light load mode" and a "normal mode", and additionally includes a mode for "speed-up traveling".

According to a third aspect of the present invention, in the configuration in which a variable displacement pump for performing constant horsepower control is mounted on the excavator,
Engine output characteristics different from "light load mode", "normal mode" and "heavy load mode" are provided, and a pressure-flow rate control diagram of a hydraulic pump is set to match the three modes. The light-load mode pressure-flow control diagram is different from the pressure-flow control diagram in the normal mode.
Assuming that the maximum pressure is the same, the diagram is a diagram which is shifted in parallel and shifted down as a whole.

According to a fourth aspect of the present invention, in the configuration in which a variable displacement pump for performing constant horsepower control is mounted on the excavator,
Engine output characteristics different from "light load mode", "normal mode" and "heavy load mode" are provided, and a pressure-flow rate control diagram of a hydraulic pump is set to match the three modes. The pressure-flow control diagram of the "heavy load mode" is different from the pressure-flow control diagram of the "normal mode".
The maximum flow rate is the same, the maximum pressure is increased, and the diagram is shifted up by parallel movement as a whole.

[0010]

Next, an embodiment of the present invention will be described. 1 is an overall view of an excavator such as a backhoe, FIG. 2 is a drawing showing a basic curve of an output characteristic curve of an engine with an electronic governor G of the present invention, and FIG. 3 is a "light load mode", a "normal mode" and a "normal mode". FIG. 4 is a diagram showing an output characteristic curve and a pressure-flow rate control diagram in each mode of “heavy load mode”, FIG. 4 is a hydraulic circuit diagram showing the arrangement of a shift-up valve VU and a shift-down valve VD, and FIG. FIG. 5 shows pressure-flow rate control diagrams in the case of “mode” and “light load mode + speed-up traveling”. FIG. 6 illustrates a pressure-flow rate control diagram of the “normal mode” and the “normal mode + increased traveling”. FIG. 7 illustrates a pressure-flow rate control diagram in the “heavy load mode”. FIG. 8 is a diagram showing a change in the pressure-flow control diagram in the “normal mode + increased traveling” and the “heavy load mode”, and FIG. 9 is a diagram showing a change in the load torque due to the relief pressure increase with respect to the output characteristic curve.

FIG. 1 shows a backhoe as a working machine, which comprises a boom 1 and an arm 2.
And a bucket 3 to perform an operation, a boom cylinder 1s for rotating the boom 1, an arm cylinder 2s for rotating the arm 2, and a bucket cylinder 3s for rotating the bucket 3
Is interposed. An output characteristic curve of each mode will be described with reference to FIGS. The "light load mode" lowers the upper limit value of the maximum engine speed, and the engine horsepower setting remains the "normal mode" horsepower setting, but the engine torque curve changes to the "normal mode" load. When the load is lower than the torque line and the load is shifted on the load torque curve at the time of light load work, and the load exceeding the torque set as the light load is applied to the engine, the "normal mode"
When a load is applied from an arbitrary no-load rotation speed, isochronous control is performed to keep the set rotation speed constant, and when a certain load ratio is exceeded, the rotation speed is changed. Is provided with an engine output characteristic for performing a reverse droop control to increase the value by a certain set value.

In the "light load mode", the maximum number of revolutions is set to 1500 when no load is applied, and when a load is applied, reverse droop control is performed so that the number of revolutions can be increased to 1700.
The torque curve is set to a rated torque of about 8.7 to 8.9 as in the “light load mode”. However, when a load is applied, the torque is increased without decreasing the rotation speed by the isochronous control. In the output characteristic of the "light load mode", the output characteristic curve of the "light load mode" is separately provided, but the output characteristic curve of the "normal mode" is hidden behind.

In the "normal mode", the upper limit of the number of revolutions that can be set by the operator is the maximum revolution number a when no load is applied. , The rotation speed is increased in proportion to the load to an arbitrary load point without decreasing the rotation speed.
+ Α, and when the load further increases, a + α is maintained without lowering the rotation speed to the rated point, and it is set in the full load rotation range without lowering the rotation speed even if the load increases from no load. The reverse droop that performs isochronous control to maintain the rotation speed when the load increases from the no-load rotation speed at the low rotation position, and increases the rotation speed by a certain value when the load exceeds a certain load factor It is provided with an output characteristic for controlling.

In the case of the "normal mode", the maximum no-load rotational speed is 1950 revolutions. When a load is applied, reverse droop control is performed in which the rotational speed increases in proportion to the torque load up to 2500 revolutions in a proportional state. . When the load further increases from 2500 revolutions, the "normal mode"
To the maximum torque. Next, when the load is further applied,
In the full-load rotation range of the "normal mode", isochronous control is used to maintain the set rotation speed without lowering the rotation speed even if the load increases compared to when there is no load. An output characteristic is provided in which the isochronous control is performed when the load is increased, and the reverse droop control is performed to increase the rotational speed by a certain value when the load factor is exceeded.

Next, the "heavy load mode" will be described.
The "heavy load mode" has two output characteristics that are completely different in the same engine. By selecting the "heavy load mode", an output diagram that fully draws out the capabilities of the engine is provided. Is provided with an output characteristic of increasing the torque by further increasing the rotation speed when a load exceeding the rated point of the "normal mode" is applied.

In the "heavy load mode", an output characteristic curve completely different from the output characteristic curve of the "normal mode" is provided. In the case of the "heavy load mode", the maximum no-load rotation speed is 1950 rotations. When a load is applied, reverse droop control is performed in which the rotation speed increases in proportion to the torque load up to 2500 rotations in a proportional state. . When the load further increases from the 2500 revolutions, the torque increases to the maximum torque in the “normal mode” by the isochronous control. When a load is further applied, reverse droop control is performed individually from the rotation speed to the full-speed of the engine to reach the output characteristic curve of the “heavy load mode”. The selection of the "light load mode", the "normal mode" and the "heavy load mode" is selected by the mode selection switch S.

As described above, the output characteristic curve of the engine is
"Light load mode", "Normal mode" and "Heavy load mode"
, And the pressure-flow rate control diagram of the hydraulic pump is also configured as shown in FIG. 3 for each of the three modes. Hydraulic pumps P1, P2 and P
3 and P4 are driven by the engine. The hydraulic pump P4 supplies working machine / travel remote control valve and signal circuit pressure oil for traveling second speed. Hydraulic pump P2
Is a boom cylinder 1 that drives boom 1 and bucket 2
s, which is supplied to the bucket cylinder 3s. The hydraulic pump P1 discharges pressure oil supplied to an arm cylinder 2s that drives the arm 2. Hydraulic pump P3
Is a pump that supplies pressure oil to a bucket cylinder 3s that drives a swing motor and blades.

The pressure-flow control diagrams of the hydraulic pumps shown in FIGS. 5 to 7 show the pressure-flow control diagrams of the hydraulic pumps P1 and P2. Although two pressure-flow control diagrams of the hydraulic pumps P1 and P2 are shown, the pressure-flow control diagrams of the hydraulic pumps P1 and P2 depend on whether the hydraulic pump P3 is at a high pressure or a low pressure. This is because the control diagram changes. Since the hydraulic pump P3 changes between 10 and 190K, the hydraulic pumps P1 and P2
Also changes between the two pressure-flow control diagrams.

In the present invention, the pressure-flow rate control diagram includes not only the three modes of "light load mode", "normal mode" and "heavy load mode" but also "light load mode + speed increasing mode". There is a mode of “normal mode + increased traveling”. The “normal mode + increased traveling” and the “heavy load mode” are configured to have the same pressure-flow rate control diagram. FIG. 5 shows a pressure-flow rate control diagram in the case of the “light load mode” and the “light load mode + increased traveling”. FIG. 6 illustrates a pressure-flow rate control diagram of the “normal mode” and the “normal mode + increased traveling”.
FIG. 7 illustrates a pressure-flow rate control diagram in the “heavy load mode”.

The "light load mode", "light load mode + increased traveling", "normal mode", and "normal mode + increased traveling"
The switching of the pressure-flow control diagram between the five modes of “heavy load mode” is performed by the shift-up valve VU shown in FIG.
And the role of the shift-down valve VD. The shift-down valve VD is turned on when a "light load mode" signal is input.
Then, the pressure oil is supplied to the oil passage PE to the hydraulic cylinder R in the direction of shifting down the swash plates of the hydraulic pumps P1 and P2. The pressure of the pressurized oil is 40K, "light load mode"
And the state in which the hydraulic cylinder R is supplied to the hydraulic cylinder R in the downshift direction of “light load mode + speed-up traveling”. Conversely, when the "heavy load mode" or the "second travel speed signal" is input to the upshift valve VU, the hydraulic cylinder Q is shifted in the direction of shifting up the swash plates of the hydraulic pumps P1 and P2.
Is supplied with pressure oil from the oil passage PF.

As a result, the hydraulic cylinder Q
The swash plates of the hydraulic pumps P1 and P2 are tilted to the shift-up side by the pressure oil to the pump. The case of the “heavy load mode” and the “running second speed signal” is the “light load mode +
This is the case of "accelerated running", "normal mode + accelerated running", and "heavy load mode". In the case of “light load mode + speed-up traveling”, the state is such that pressure oil is supplied to both the hydraulic cylinder R and the hydraulic cylinder Q.

When the shift-up valve VU is switched, hydraulic oil is supplied to the oil passage PF, and the hydraulic cylinder Q is extended, and the swash plates of the hydraulic pumps P1 and P2 are tilted to the shift-up side. Further, another oil passage is configured such that the pressure oil is also supplied to the relief valve of the control valve C / V, and the relief valve increases the relief pressure.

[0023]

As described above, the present invention has the following advantages. In the configuration in which the variable displacement pump for performing the constant horsepower control is mounted on the excavator, the output characteristic of the engine is set to the “light load mode”.
And different modes from the "normal mode" and the "heavy load mode", and set the pressure-flow rate control diagram of the hydraulic pump to match the three modes. By setting the control diagram separately, it is possible to supply the discharge pressure and the flow rate of the hydraulic oil appropriate for each mode.

According to a second aspect of the present invention, in the configuration in which the variable displacement pump for performing the constant horsepower control is mounted on the excavator, the output characteristics of the engine are set to the "light load mode" and the "normal mode".
And a different mode from the "heavy load mode", and set the pressure-flow rate control diagram of the hydraulic pump to match the three modes, respectively, and furthermore, the "light load mode" and the "normal mode".
In addition, since the mode for "speed-up" is added separately, the "light load mode", "normal mode" and "heavy load mode" cannot be used alone. As a result, a pressure-flow rate control diagram can be provided, and hydraulic oil having a pressure and a flow rate matching the load of the engine could be supplied.

According to a third aspect of the present invention, in the configuration in which the variable displacement pump for performing the constant horsepower control is mounted on the excavator, the output characteristics of the engine are set to the "light load mode" and the "normal mode".
And a different one from the “heavy load mode”, and set the pressure-flow control diagram of the hydraulic pump to match the three modes, respectively. The pressure-flow rate control diagram is the same as the maximum pressure, and the diagram is shifted in parallel and shifted down as a whole. Since high pressure oil is not supplied at a large flow rate, energy saving and fuel saving can be achieved.

According to a fourth aspect of the present invention, in the configuration in which the variable displacement pump for performing the constant horsepower control is mounted on the excavator, the output characteristics of the engine are set to the "light load mode" and the "normal mode".
And the heavy load mode are different from each other, and the pressure-flow control diagrams of the hydraulic pumps corresponding to the three modes are respectively set. ), The maximum pressure was increased, the maximum pressure was increased, and the whole was translated and shifted up, so in the "heavy load mode", the hydraulic oil with high pressure and large flow rate , It is possible to perform a strong work with strong oil pressure.

[Brief description of the drawings]

FIG. 1 is an overall view of an excavator such as a backhoe.

FIG. 2 is a drawing showing a basic curve of an output characteristic curve of the engine with the electronic governor G of the present invention.

FIG. 3 is a view showing an output characteristic curve and a pressure-flow rate control diagram in each of a “light load mode”, a “normal mode”, and a “heavy load mode”.

FIG. 4 is a hydraulic circuit diagram showing an arrangement of a shift-up valve VU and a shift-down valve VD.

FIG. 5 is a pressure-flow rate control diagram in the case of a “light load mode” and a “light load mode + increased traveling”.

FIG. 6 is a pressure-flow rate control diagram of “normal mode” and “normal mode + increased traveling”.

FIG. 7 is a pressure-flow rate control diagram in a “heavy load mode”.

FIG. 8: “Normal mode + speed-up traveling” and “heavy load mode”
6 is a diagram showing a change in a pressure-flow rate control diagram in FIG.

FIG. 9 is a diagram showing a change in load torque due to relief boosting with respect to an output characteristic curve.

[Explanation of symbols]

 1 Boom 2 Arm 3 Bucket VU Shift up valve VD Shift down valve R, Q Hydraulic cylinder

Claims (4)

[Claims] An excavating machine in which a variable displacement pump for performing constant horsepower control is mounted, wherein output characteristics of an engine are different from those of a "light load mode", a "normal mode", and a "heavy load mode". And a pressure-flow rate control diagram of a hydraulic pump adapted to the three modes is set, respectively. 2. A configuration in which a variable displacement pump for performing constant horsepower control is mounted on an excavator, wherein output characteristics of the engine are different from those of a "light load mode", a "normal mode", and a "heavy load mode". To set the pressure-flow rate control diagram of the hydraulic pump to match the three modes, and furthermore, the mode for the "light load mode", the "normal mode" and the "speed-up traveling" A hydraulic control mechanism for an excavator, wherein a hydraulic control mechanism is additionally provided. 3. A configuration in which a variable displacement pump for performing constant horsepower control is mounted on an excavator, wherein output characteristics of the engine are different from those of a "light load mode", a "normal mode", and a "heavy load mode". Are provided, and pressure-flow rate control diagrams of the hydraulic pump to be matched with the three modes are respectively set,
The pressure-flow control diagram in the "light load mode" should be the same as the pressure-flow control diagram in the "normal mode", with the same maximum pressure, but shifted in parallel and shifted down as a whole. A hydraulic control mechanism for an excavating machine. 4. A configuration in which a variable displacement pump for performing constant horsepower control is mounted on an excavator, wherein output characteristics of an engine are different from those of a "light load mode", a "normal mode", and a "heavy load mode". Are provided, and pressure-flow rate control diagrams of the hydraulic pump to be matched with the three modes are respectively set,
The pressure-flow control diagram in the "heavy load mode" is the same as the pressure-flow control diagram in the "normal mode", assuming the same maximum flow rate, increasing the maximum pressure, and moving up in parallel as a whole. A hydraulic control mechanism for an excavator, wherein the hydraulic control mechanism is a diagram.