JP2000104290A - Controller for construction machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a controller for a construction machine preventing the overturn of a machine body in a slope without losing the workability. SOLUTION: An engine 5 drives a plurality of variable delivery hydraulic pumps 15, 16 so as to actuate a hydraulic actuator provided in a traveling body and an upper revolving structure. In this case, only such a hydraulic actuator as provided in the upper revolving structure and losing the balance of the machine by the operation in a slope is provided with an inclinometer 6 detecting an inclination angle of the machine and a controller 20 which restricts a pressure oil discharge of a variable delivery hydraulic pump 15 based on the inclination angle detected by the inclinometer 6.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a construction machine such as a hydraulic shovel, and more particularly, to a construction machine control device for preventing a machine body from overturning during work on a slope.

[0002]

2. Description of the Related Art Conventionally, as a construction machine having a function of preventing overturning on a slope, a vehicle safe driving system described in Japanese Patent Application Laid-Open No. 7-3844 is known.

[0003] This type of system, as shown in FIG.
The present invention can be applied to a construction machine in which the engine 50 drives the variable displacement hydraulic pumps 51 and 52 and operates the front attachment 53 with hydraulic pressure discharged from the variable displacement hydraulic pumps 51 and 52. An inclinometer 54 that generates an angle signal according to the inclination is installed on the vehicle body 55, and a plurality of inclination angles (first angle or less, first angle
Angle to the second angle, the second angle or more), and a different signal is provided to the controller 56 for each inclination angle.

[0004] The controller 56 does not perform control when the inclination angle output from the inclinometer 54 is equal to or less than the first angle.
In the range of the first angle to the second angle, the variable displacement hydraulic pump 5
The variable displacement hydraulic pump is controlled so that the absorption torque of the pumps 1, 52 is changed, and the pump displacement angle is minimized at the second angle or more.

According to such a configuration, as shown in the PQ characteristic diagram of FIG. 9, the absorption torque is automatically reduced as the inclination angle θ increases, and as a result, the work / running speed on the sloped ground Are both slowed down, thereby preventing falls and increasing safety.

[0006]

However, in the conventional safe driving system, when the inclination angle exceeds the first angle, the absorbing torque of the variable displacement hydraulic pump is reduced uniformly, so that all the hydraulic actuators need to be operated. There is a problem that the property is reduced. Specifically, there is a problem that even if an attempt is made to escape from a sloped land, it is not possible to escape quickly because the pressure oil supply flow rate to the traveling motor is also restricted.

SUMMARY OF THE INVENTION The present invention has been made in consideration of the problems of the conventional construction machines described above, and a control device for a construction machine which does not impair workability while ensuring safety by preventing a fall on an inclined land. To provide.

[0008]

According to the present invention, an upper revolving unit is mounted on a traveling body, a plurality of variable displacement hydraulic pumps are driven by a prime mover, and pressure oil discharged from each variable displacement hydraulic pump is used. In a construction machine that operates a hydraulic actuator provided on a traveling body and an upper revolving structure, an inclination angle detecting means for detecting a machine body inclination angle of the construction machine, and a hydraulic actuator provided on the upper revolving structure, and Limiting means for limiting the hydraulic oil discharge flow rate of the variable displacement hydraulic pump connected thereto only on the hydraulic actuator whose operation loses the balance of the body based on the inclination angle detected by the inclination angle detecting means; And a control device for a construction machine comprising:

In the present invention, it is preferable that the limiting means increase the limiting amount of the pressure oil discharge flow rate as the inclination angle detected by the inclination angle detecting means increases. It is preferable to stop the discharge of the pressure oil when the inclination angle exceeds the allowable inclination angle.

According to the present invention, during the operation of the construction machine, the inclination angle of the body is detected by the inclination angle detecting means and is given to the limiting means. In the limiting means, a hydraulic actuator provided on the upper-part turning body according to the detected inclination angle,
For example, a limit signal is output to a variable displacement hydraulic pump connected to a swing motor. Thus, the turning speed of the upper turning body having a large turning moment of inertia can be reduced, and the body can be prevented from tipping over. In addition, for a variable displacement hydraulic pump connected to a travel motor that is a hydraulic actuator other than the upper revolving superstructure, for example,
Since the pressure oil discharge flow rate is not limited, it is possible to escape from the sloped land quickly.

Further, in the present invention, when there is provided an operating means for operating a hydraulic actuator provided on the upper swing body and an operation detecting means for detecting the presence or absence of an operation by the operating means, the limiting means is provided by the operation detecting means. For the hydraulic actuator that is detected to be in the operating state, the pilot pressure of the control valve that controls the hydraulic actuator can be limited.

According to the present invention, during the operation of the construction machine, the inclination angle of the body is detected by the inclination angle detecting means and given to the restricting means, and the restricting means is connected to the upper swing body in accordance with the detected inclination angle. The hydraulic oil discharge flow rate of the variable displacement hydraulic pump is limited, but when the operation of a hydraulic actuator provided on the upper rotating body is detected, the operated hydraulic actuator, for example, a pilot of a control valve for controlling a swing motor is controlled. The restriction is performed by restricting the pilot pressure introduced to the port.
Therefore, it is possible to selectively limit only the hydraulic actuator operated by the operator among the plurality of hydraulic actuators provided in the upper swing body. By selectively restricting the operated hydraulic actuators among the hydraulic actuators provided on the upper-part turning body in this way, the operating speed of only the restricted hydraulic actuators can be reduced. There is an advantage that workability of the hydraulic actuator is not impaired. In addition, as a hydraulic actuator whose operation is preferably restricted, a swing motor, a boom cylinder, an arm cylinder and the like are shown. It should be noted that the operation of the bucket cylinder does not affect the overturn, so there is no need to limit the operation.

In the present invention, when the upper revolving structure has a front attachment and load detecting means for detecting the magnitude of a load acting on the front attachment, the limiting means is detected by the load detecting means. It can be configured such that when the load exceeds a predetermined value, the pressure oil discharge flow rate is limited.

According to the present invention, when earth and sand (load) is contained in, for example, a bucket of the front attachment and the magnitude of the load detected by the load detecting means exceeds a predetermined value, the limiting means sets the inclination of the body. The operation of a hydraulic actuator, for example, a swing motor provided on the upper swing body is limited according to the angle. Thereby, in the operation of turning the upper revolving structure to the valley side with the earth and sand in the bucket, it is possible to prevent the body from tipping over.

In the present invention, the limiting means adjusts the tilting angle of the regulator or reduces the rotation speed of the prime mover to limit the hydraulic oil discharge flow rate when limiting the hydraulic oil discharge flow rate. Can be restricted.

In the present invention, the vehicle body inclination angle of the construction machine includes the inclination of the grounded body in the front-rear direction and the width direction.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail based on an embodiment shown in the drawings.

FIG. 1 shows a configuration in which a control device for a construction machine according to the present invention is applied to a hydraulic shovel.

In FIG. 1, an excavator 1 has an upper revolving unit 4 rotatably mounted on a traveling unit 3 traveling by a traveling motor 2, and an engine 5 and an inclination angle detecting means in the upper revolving unit 4. The inclinometer 6 and the turning motor 7 are arranged.

The upper swing body 4 swings about a center axis OO ', and an inclinometer 6 is arranged on the center axis OO'. The inclinometer 6 has a horizontal line H. It is possible to measure a body inclination angle with respect to L (hereinafter, referred to as a ground angle θ).

A front attachment F is provided in front of the upper revolving unit 4, and the front attachment F is provided with a boom 9 which is raised and lowered by a boom cylinder 8.
, An arm 11 pushed or pulled by an arm cylinder 10, and a bucket 13 swinging by a bucket cylinder 12. These cylinders 8, 10, 12 are discharged from a variable displacement hydraulic pump described later. It operates by receiving a supply of pressurized oil.

FIG. 2 shows a first embodiment of a hydraulic control circuit mounted on the hydraulic excavator 1. In the figure, a pilot pump 1
4, a first variable displacement hydraulic pump (hereinafter, referred to as a first hydraulic pump) 15 and a second variable displacement hydraulic pump (hereinafter, referred to as a second hydraulic pump) 16 are connected.

The hydraulic oil discharged from the first hydraulic pump 15 passes through a control valve 17 for controlling a boom and a control valve 18 for controlling a swing motor connected in series with the control valve 17 to control the hydraulic oil tank T.
Is returned to. Note that the swing motor 7 is connected to the control valve 18.

The flow rate of the hydraulic oil discharged from the first hydraulic pump 15 is adjusted by a regulator 19 for tilting the angle of the pump swash plate. The regulator 19 converts a control signal output from a controller 20 as a limiting means into a hydraulic signal. The control is performed by an electromagnetic proportional valve 21 that performs conversion.

The pilot primary pressure Sp discharged from the pilot pump 14 is introduced into a remote control valve 23. When the operating lever (operating means) 23a of the recommon valve 23 is operated in the direction A, the pilot secondary pressure Sp1 acts on the pilot port 18a of the control valve 18 to switch the valve from the neutral position A to the A position, and the swing motor 7 Rotates forward. Conversely, when the operation lever 23a is operated in the direction B, the pilot secondary pressure Sp2 acts on the pilot port 18b of the control valve 18 to switch the valve from the neutral position A to the C position, and the swing motor 7 rotates in the reverse direction. . In addition, the ground angle signal Sa output from the inclinometer 6
Is given to the controller 20.

The hydraulic oil discharged from the second hydraulic pump 16 is supplied to the hydraulic oil tank T through a control valve 25 for controlling the traveling motor and a control valve 26 for controlling the bucket connected in series with the control valve 25. Will be returned.

Next, a description will be given of the control operation of the hydraulic control circuit having the above configuration when the work is performed on a slope such as that shown in FIG.

In the operation on the slope, the central axis O-
O ′ is the horizontal line H. It is inclined by θ degrees with respect to L. When the swing operation of the upper swing body 4 is performed in this posture, the weight of the front attachment works to accelerate the swing speed of the upper swing body 4.

However, in the configuration of the hydraulic control circuit of the present embodiment, the inclinometer 6 detects the ground angle θ and gives it to the controller 20 as the ground angle signal Sa. The controller 20 detects the detected ground angle signal Sa Based on
The stability of the aircraft during the turning operation is determined, and if it is determined that the stability cannot be ensured, control is performed to output the limit signal Sb to the electromagnetic proportional valve 21. In particular,
For example, when the detected ground angle θ exceeds the allowable ground angle θlimit in comparison with the allowable ground angle (allowable tilt angle) θlimit stored in advance in the memory 20 a of the controller 20, the limit signal is sent to the electromagnetic proportional valve 21. By outputting Sb, the tilt angle of the first hydraulic pump 15 is changed, and the flow rate of the hydraulic oil supplied to the control valve 18 is reduced. Therefore, the pressure oil supplied to the turning motor 7 decreases, and the turning speed is limited.

On the other hand, since the second hydraulic pump 16 does not limit the flow rate of the hydraulic oil, a normal working speed can be obtained. Specifically, when escaping from a slope,
Since the flow rate of the pressure oil is not restricted for the control valve 25 that operates the traveling motor 2, it is possible to escape quickly and avoid danger.

FIG. 3 shows a second embodiment of the hydraulic control circuit. In the following description, the same components as those in FIG. 2 are denoted by the same reference numerals, and description thereof will be omitted.

In the configuration shown in FIG.
An electromagnetic proportional valve 22 is provided in an oil path connecting the remote controller 4 and the remote control valve 23, and the controller 20 outputs a limit signal Sc to the electromagnetic proportional valve 22. In this case, by outputting the limit signal Sc, the pilot primary pressure Sd1 decreases, and even if the operation lever 23a is operated deep, the pilot secondary pressure Sp1 or Sp2 does not increase and the valve opening of the control valve 18 does not increase. . Even in the case of such a configuration, the turning speed of the turning motor 7 can be limited to a low speed as in the first embodiment. The electromagnetic proportional valve 22 can be provided in an oil passage connecting the remote control valve 23 and the control valve 18.

FIG. 4 shows a third embodiment of the hydraulic control circuit of the present invention. In the configuration shown in the figure, pressure sensors 24a and 24b as operation detecting means are provided in respective oil passages connecting the remote control valve 23 and the pilot ports 18a and 18b of the control valve 18, and these pressure sensors 24a or 24b are provided. Is supplied to the controller 20.

The controller 20 is provided with the ground angle signal Sa from the inclinometer 6 as described above, and when either of the operation signals So1 or So2 is input,
The limit signal Sb or Sc is output to the electromagnetic proportional valve 21 or the electromagnetic proportional valve 22.

That is, when the turning operation is actually performed in a tilted state in which the stability of the machine body cannot be ensured during the turning, the controller 20 controls the operated turning motor 7.
, The turning speed is selectively limited.

The hydraulic actuators to be limited are not limited to the swing motor 7, but can be limited to the boom and the arm. For example, when a heavy work tool (a hydraulic breaker, a crusher, or the like) is attached to the tip of the arm 11, when the arm is pushed out, the central axis OO 'is obtained.
The distance from the tool to the work tool increases, and the position of the center of gravity of the aircraft shifts forward. Therefore, if the arm is pushed out abruptly during the turning operation, there is a possibility that the balance of the body may be lost and the aircraft may fall.

As described above, if the operating speed of a boom or an arm that moves the center of gravity of the machine by operating is limited at the same time as the turning speed is limited, the work on the slope can be performed more stably. Can be.

As described above, the controller 20 compares the allowable ground angle stored in the memory 20a in advance,
When the detected ground angle θ exceeds the allowable ground angle θlimit, the limit signal Sb is output.
The control below t will be described below.

The memory 20a of the controller 20 stores a limit value that increases continuously or stepwise as the ground angle θ increases from “θmin” to “θlimit”. Is detected, the controller 20 reads the limit value corresponding to the θ from the memory 20a and outputs the limit value as the limit signal Sb or Sc. However, θmin indicates the upper limit of the ground angle at which the user can safely work even in the inclined posture. Therefore, in the range from zero to θmin, the limit value is zero and the limit signal is not output. .

In the configuration in which the limit value is output in accordance with the ground angle θ, even when traveling on a work site having uneven terrain, the turning speed is increased in accordance with the inclination angle, for example, as the ground angle θ increases. Since the restriction can be made gradually, it is possible to eliminate the uncomfortable feeling at the time of the operation in which the turning speed is rapidly reduced when the ground angle θ exceeds the allowable ground angle θlimit. Further, an optimum turning speed according to the ground angle can be obtained.

FIG. 5 shows a fourth embodiment of the hydraulic control circuit. In the configuration shown in FIG.
And the pilot port 18a of the control valve 18,
18b to oil passages 31a and 31
b is branched, and a shuttle valve 32 is provided at a connection portion between the oil passages 31a and 31b. A pressure sensor 34 is provided in an oil passage 33 communicating with the oil passage on the side selected by the shuttle valve 32 at a higher position. Therefore, the operation lever 23
When a is operated to either one, a signal is output from the pressure sensor 34 and given to the controller 35,
The operation of the swing motor 7 can be recognized.

A display 36 is connected to the controller 35. The display 36 displays the ground angle θ of the hydraulic shovel, the attitude of the aircraft body, the abnormal lamp for notifying that the allowable ground angle θlimit has been exceeded, and the like. It is supposed to.

A boom cylinder 37 is connected to the control valve 17, and a pressure sensor 39 is provided in an oil passage 38 connected to the head side oil chamber 37a. The pressure sensor 39 outputs a signal when the pressure in the head-side oil chamber 37a exceeds a pressure (predetermined value) during normal operation, and the output signal is given to the controller 35. Reference numeral 40 denotes a governor motor controlled by the controller 35, which controls the rotation speed of the engine 5.

The control operation of the hydraulic circuit having the above configuration is described as follows.
This will be described with reference to the flowchart shown in FIG.

While working on a slope, the inclinometer 6
Output a ground angle signal from the controller 35, the controller 35 calculates a ground angle θ (step S100).

Next, the ground angle θ ≧ permissible ground angle θlimit
Is determined (step S101), and if yes, it is further determined whether or not the swing motor 7 is operated (step S102).

If "yes" in step S102, it is determined whether the head pressure in the head side oil chamber 37a of the boom cylinder 37 is the normal pressure based on whether a signal is output from the pressure sensor 39 (step S10).
3).

If "yes" here, the tilt angle command value q of the hydraulic pump 15 is set to the pump tilt limit qlimit (step S104), and the set tilt angle command value q is set as the limit signal Sb by electromagnetic proportionality. Output to the valve 21 (step S10
Five).

With such a configuration, even when a dangerous operation such as turning to the valley side with the earth and sand in the bucket 13 is performed during work on a slope, the aircraft loses balance and falls over. There is no fear. Moreover, the electromagnetic proportional valve 2
1. Since the amount of pressurized oil discharged from the first hydraulic pump 15 is limited via the regulator 19 and the amount of pressurized oil supplied to the turning motor 7 is reduced, the turning speed can be reliably reduced.

It should be noted that also in this configuration, the supply amount of the hydraulic oil is not limited for the second hydraulic pump 16, so that the hydraulic actuator such as the traveling motor can be operated at the normal speed.

Further, the controller 35 is not limited to limiting the amount of pressure oil discharged from the first pump 15 as described above,
Can be reduced.

In this case, the controller 35 outputs a control signal to the governor motor 40 to reduce the rotation speed of the engine 5. Also in this configuration, the rotation speed of the turning motor can be reliably reduced.

In each of the above-described embodiments, when the flow rate is reduced by tilting the pump swash plate, the pressure oil discharge flow rate Q is set according to the PQ diagram shown in FIG. The PQ diagram shown in the figure shows the relationship between the pump pressure P and the flow rate Q set corresponding to the ground angle θ,
As the ground angle θ of the hydraulic excavator increases, only the flow rate Q is limited without changing the pressure P.

The construction machine of the present invention can be applied not only to the excavator of the above embodiment but also to a hydraulic crane.

[0055]

As is apparent from the above description,
ADVANTAGE OF THE INVENTION According to this invention, the control apparatus of the construction machine which does not impair workability | operativity can be provided while ensuring safety by preventing overturn on the slope ground.

Further, according to the present invention, for a specific hydraulic actuator whose operation on a sloped land will lose the balance of the body, the hydraulic oil discharge flow rate of the variable displacement hydraulic pump connected to the hydraulic actuator is determined. Is restricted according to the inclination angle of the body, whereby the body can be prevented from tipping over. Further, since the operation of a hydraulic actuator that does not fall down even when it is activated, for example, a traveling motor, is not limited, it is possible to escape quickly from a slope.

According to the present invention having the operation detecting means, the hydraulic oil discharge flow rate of the variable displacement hydraulic pump is limited in accordance with the inclination angle, but when the operation of the hydraulic actuator provided on the upper rotating body is detected. In order to limit the pilot pressure of the control valve that controls the operated hydraulic actuator, it is possible to selectively limit only the hydraulic actuator operated by the operator among the plurality of hydraulic actuators provided in the upper-part turning body. it can.

According to the present invention having the load detecting means, when the load of the front attachment exceeds a predetermined value, the operation of the hydraulic actuator provided on the upper revolving unit is restricted, for example, a state in which sediment is contained in the bucket. In the operation of turning the upper revolving structure toward the valley side, it is possible to prevent the body from tipping over.

[Brief description of the drawings]

FIG. 1 is a side view showing a working state of a hydraulic shovel equipped with a control device according to the present invention.

FIG. 2 is a hydraulic circuit diagram showing a first embodiment of a control device according to the present invention.

FIG. 3 is a hydraulic circuit diagram showing a second embodiment of the control device according to the present invention.

FIG. 4 is a hydraulic circuit diagram showing a third embodiment of the control device according to the present invention.

FIG. 5 is a hydraulic circuit diagram showing a fourth embodiment of the control device according to the present invention.

FIG. 6 is a flowchart illustrating a control operation according to a fourth embodiment.

FIG. 7 is a PQ diagram illustrating flow rate limitation according to the present embodiment.

FIG. 8 is a hydraulic circuit diagram showing control on a slope according to a conventional construction machine.

FIG. 9 is a PQ diagram illustrating a conventional pressure / flow rate limitation.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Hydraulic excavator 2 Traveling motor 3 Traveling body 4 Upper revolving superstructure 5 Engine 6 Inclinometer 7 Rotating motor 8 Boom cylinder 9 Boom 15 First variable displacement hydraulic pump 16 Second variable displacement hydraulic pump 17 Control valve for boom 18 Rotating motor Control valve 19 Regulator 20 Controller 21 Proportional solenoid valve 23 Remote control valve 23a Operation lever

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Koji Yamashita 3-12-4 Gion, Asaminami-ku, Hiroshima City Inside Aburaya Heavy Industries, Ltd. (72) Kenrei Suzuki 1-18-18 Nishiki, Naka-ku, Nagoya City Takenaka Corporation Nagoya Branch (72) Inventor Shoji Otaki 1-18-18 Nishiki, Naka-ku, Nagoya City No. 22 Takenaka Corporation Nagoya branch F-term (reference) 2D003 AA01 AB02 AB03 BA06 BA07 BB10 DA03 DA04 DB02 DB04 2D015 DA04 GA02 GA03 GB03 HA03 HB02 HB04

Claims (6)

[Claims] An upper revolving unit is mounted on a traveling body, a plurality of variable displacement hydraulic pumps are driven by a prime mover, and the traveling unit and the upper revolving unit are driven by pressure oil discharged from each variable displacement hydraulic pump. A construction machine that operates a hydraulic actuator provided in the construction machine, wherein an inclination angle detecting means for detecting a body inclination angle of the construction machine; and Limiting means for limiting the hydraulic oil discharge flow rate of the variable displacement hydraulic pump connected thereto only for the hydraulic actuator that loses balance based on the inclination angle detected by the inclination angle detecting means. A control device for a construction machine, comprising: 2. The control device for a construction machine according to claim 1, wherein the limiting unit increases the restriction amount of the pressure oil discharge flow rate as the tilt angle detected by the tilt angle detecting unit increases. 3. The control of a construction machine according to claim 1, wherein the restricting unit stops the discharge of the pressure oil when the inclination angle detected by the inclination angle detecting unit exceeds an allowable inclination angle. apparatus. 4. An operating means for operating a hydraulic actuator provided on the upper swing body, and an operation detecting means for detecting presence or absence of an operation by the operating means, wherein the restricting means is operated by the operation detecting means. The control device for a construction machine according to any one of claims 1 to 3, wherein a pilot pressure of a control valve that controls the hydraulic actuator that is detected to be in a state is limited. 5. The vehicle according to claim 1, further comprising: a front attachment to the upper revolving unit; and a load detection unit configured to detect a magnitude of a load acting on the front attachment, wherein the limiting unit detects a load detected by the load detection unit. The pressure oil discharge flow rate is limited when exceeding a predetermined value.
3. The control device for a construction machine according to any one of 3. 6. The pressure oil discharge of the variable displacement hydraulic pump is controlled by adjusting a tilt angle of a regulator or reducing a rotation speed of the prime mover in limiting the pressure oil discharge flow rate. Claim 1 for limiting the flow rate
6. The control device for a construction machine according to any one of claims 5 to 5.