JP2005163300A - Hydraulic excavator with crane function - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hydraulic excavator with a crane function, more safely performing crane work in the hydraulic excavator. <P>SOLUTION: When an attachment of the hydraulic excavator with a crane function enters "crane work mode" (Y is determined in the step 80) and it is detected that a bucket 18 of the attachment is not completely closed (N is determined in the step 82), a warning to that effect is given to a worker (step 84). This determination is always performed while the attachment is in the crane work mode. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a hydraulic excavator with a crane function.

  A hydraulic excavator is a machine that excavates earth and sand, crushed rocks, and the like. For this reason, a hydraulic excavator having a crane function in which a hydraulic excavator has a function as a crane has been widely used.

  FIG. 4 shows a configuration example of a conventional hydraulic excavator with a crane function (see Patent Document 1).

  The excavator 12 includes a boom 14, an arm 16, and a bucket 18 as an attachment A. The crane work is performed via a lifting tool 22 arranged in the vicinity of the bucket 18 at the tip of the attachment A.

  When the excavator 12 is used as a crane, measures must be taken to prevent the excavator 12 from overturning during the crane operation. Therefore, in this hydraulic excavator 12 with a crane function, the posture of the attachment A such as the turning radius R (or working radius r) from the turning shaft 24 (or the starting point 9 of the boom 14) of the hydraulic excavator 12 to the lifting tool 22 or the like. The allowable limit value (rated load) is determined in advance according to the information, the suspension load Wg currently acting on the suspension 22 is obtained, and this is obtained by displaying it on a display device (not shown). The crane work can be performed within a range in which the suspension load Wg does not exceed the limit value.

  In order to calculate the suspension load Wg, a boom angle sensor 26 and an arm angle sensor 28 are attached to the excavator 12, and the boom 14 swings at the swing center 9 (starting point of the boom 14) by the boom angle sensor 26. The movement angle (boom angle) θ1 is detected by the arm angle sensor 28, and the swing angle (arm angle) θ2 of the arm 16 at the swing center 11 is detected. Further, a pressure sensor 36 for detecting the bottom pressure Pb1 of the boom cylinder 34 is provided.

  As a result of calculating the suspension load Wg and the rated load Ws from each detected value, an alarm is issued when it is determined that the suspension load Wg exceeds the rated load Ws.

  By the way, when performing a crane operation, it is assumed that the excavation bucket 18 is retracted to a fully closed position (so-called cloud position). This is to avoid physical interference such as contact between the bucket 18 and the suspended load W. Therefore, each arithmetic expression is set on the assumption that the bucket 18 is in a completely closed state. Therefore, if the actual position (swinging angle) of the bucket 18 is not fully closed, the limit calculation of the suspended load W is performed. As a result, the reliability of the result itself is lost.

  In consideration of this point, in Japanese Patent Application Laid-Open No. 2001-182102, only when the bucket is stored in the fully closed position, the operation of the display unit that displays the suspension load acting on the suspension is permitted (fully closed). A technique has been proposed in which the display means is not allowed to operate in a state where it is not stored in a position) and an accurate suspension load can be displayed (see Patent Document 2).

Japanese Patent Laid-Open No. 11-232081 JP 2001-182102 A

  However, during actual work, the bucket may be engaged in crane work before it reaches the fully closed position. In this case, even if the display means remains inactive and the load display of the suspended load is displayed. Even if the suspension was stopped, there was a problem that the suspended load itself had already started to be lifted.

  Also, in this type of conventional hydraulic excavator, when the crane operation mode is set, the remote control valve for opening and closing the bucket is operated by the operator's carelessness. In order to prevent the occurrence of a situation that interferes with the operation, a fail-safe function is provided so that the bucket does not operate in the opening direction even when the remote control valve is operated in the crane work mode. Many things (operation in the closing direction of the bucket is possible).

  However, even in a hydraulic excavator in which the bucket is not operated in the opening direction in the crane operation mode, the bucket may naturally open due to hydraulic pressure leakage during the crane operation. The problem arises that work will be done.

  The present invention has been made to solve such a conventional problem, and can perform a crane operation in a hydraulic excavator more safely and smoothly under accurate suspension load information. The challenge is to provide a hydraulic excavator with a pad.

  The present invention relates to a hydraulic excavator with a crane function configured to be switchable between an excavation work mode in which the attachment is used for excavation work and a crane work mode in which the attachment is used to lift and move an object. Means for detecting whether or not the work is in the crane work mode; means for detecting whether or not the bucket of the attachment used in the excavation work mode is in a fully closed position; and work in the attachment And a means for automatically driving the bucket to the fully closed position when it is detected that the bucket is not in the fully closed position and the bucket is not in the fully closed position. It is.

  In the present invention, when it is detected that the work in the attachment is in the crane work mode and the bucket is not in the fully closed position, the fail-safe function is present regardless of the operation of the remote control valve of the worker's bucket at that time. Regardless of the presence or absence of this, the bucket is automatically (forcedly) driven to the fully closed position.

  As a result, even if the operator enters the crane operation mode without confirming the fully closed state, the bucket is reliably driven to the fully closed position, so that the buffering of the bucket and the suspended load can be reliably prevented, In addition, a highly reliable suspension load can always be calculated. In addition, since the fully closing operation is automatically performed without bothering the operator's hand, the smoothness of the work can be improved. This action works particularly effectively in a hydraulic excavator provided with fail-safe means for disabling the operation of the remote control valve for opening and closing the bucket in the crane work mode.

  Crane work on a hydraulic excavator can always be performed safely and smoothly under safe conditions.

  Hereinafter, an example of an embodiment of the present invention will be described in detail with reference to the drawings. In addition, in order to make an understanding easy, the same code | symbol is used about the member similar to the past.

  FIG. 2 shows a main configuration of a hydraulic excavator 12S with a crane to which the present invention is applied.

  The attachment A includes a boom 14, an arm 16, and a bucket 18, and is driven by a boom cylinder 34, an arm cylinder 36, and a bucket cylinder 38, respectively. This basic configuration is the same as the conventional one. Further, in order to detect the boom angle θ1 of the boom 14, the arm angle θ2 of the arm 16, and the bucket angle θ3 of the bucket 18, a boom angle sensor 26 and an arm angle sensor are provided at the swing centers (starting points) 9, 11, and 13, respectively. 28 and a bucket angle sensor 29 are respectively disposed. Further, pressure sensors 35 and 37 for determining the bottom pressure Pb1 and the rod pressure Pb2 of the boom cylinder 34 are arranged on the bottom side 34a and the rod side 34b of the boom cylinder 34, respectively.

  The output signals of these sensors are respectively input to the analog ports 50 to 54 of the controller CL, subjected to analog-digital conversion, and then used as parameters for arithmetic processing as will be described later.

  On the other hand, the main part of the drive hydraulic circuit Cb of the bucket cylinder 38 among the hydraulic circuits for driving the cylinders of the hydraulic excavator 12S is shown in the lower half of FIG. Note that a similar hydraulic circuit is basically incorporated in driving the boom cylinder 34 and the arm cylinder 36.

  The hydraulic circuit Cb is switched by an operator's operation, and is switched by a remote control valve 60 that switches a generation mode of a pilot pressure that determines a driving direction of the bucket 18, and a pilot pressure generated by the remote control valve 60. The control valve 62 mainly supplies a predetermined hydraulic pressure to the rod side 38a and the bottom side 38b of the cylinder 38.

  Reference numeral 66 denotes a regulating solenoid valve arranged to perform an operation described later when the excavator 12S is set to the crane work mode. Reference numeral 70 is a monitor that displays the suspended load Wg and the rated load Ws of the suspended load W that is lifted by a signal from the digital port 56, and 72 is a buzzer that generates an alarm by a signal from the digital port 57. 74 is a warning light that emits light in response to a signal from the digital port 58.

  The excavation work mode and the crane work mode are switched by a switch (not shown) attached to the monitor 70, and the operator operates the switch to input a desired work mode to the controller CL.

  Hereinafter, for the sake of convenience, a more detailed description of the configuration of the individual members and a description of their operation will be given together.

  When the remote control valve 60 is driven to the bucket closing side 60a by an operator to operate the bucket 18 in the closing direction, the pilot pressure Po from the pilot line Lo is output as the pilot pressure P1 to the pilot line L1 side. The On the other hand, in the case of the opening operation, the remote control valve 60 is driven to the bucket opening side 60b, and the pilot pressure P2 is output to the pilot line L2 side.

  Now, for example, it is assumed that an operator operates the bucket 18 in the opening direction on the driver's seat. In this case, the pilot pressure P2 generated on the pilot line L2 side reaches the control valve 62 via the regulating solenoid valve 66 and the line L3, and switches the control valve 62 to the open position 62b. As a result, the line pressure PL from the hydraulic power source 64 is led to the rod side 38a of the bucket cylinder 38 through the control valve 62 and the line L4, and the bucket 18 is opened.

  At this time, the line L5 on the bottom side of the control valve 62 communicates with the drain 65 so that the opening operation of the bucket 18 is smoothly performed.

  When the bucket 18 is stopped at an arbitrary position, the remote control valve 60 is set to the neutral state shown in FIG. In this state, since the pilot lines L1, L2 (L3) from the remote control valve 60 are both released to the drain 67, the control valve 62 is returned to the position (neutral position) shown in FIG. Both the line L4 on the side and the line L5 on the bottom side are blocked (blocked). As a result, the bucket cylinder 38 is fixed and maintained in that state, and the bucket 18 stops.

  On the other hand, if the operator operates the bucket 18 in the closing direction on the driver's seat, the pilot pressure P1 generated on the pilot line L1 side in this case switches the control valve 62 to the closed position 62a. As a result, the line pressure PL from the hydraulic pressure source 64 is led to the bottom side 38b of the bucket cylinder 38 through the control valve 62 and the line L5, and the bucket reaches the fully closed position as shown in FIG. 18 is closed.

  The regulation solenoid valve 66 is normally located at the position shown in the drawing (that is, the position where the pilot pressure P2 of the line L2 can be transmitted to the line L3 side). The restriction solenoid valve 66 is switched to the other position 66a side by a signal from the output port 55 of the controller 50 when the attachment A is set to the crane work mode, and the operator controls the remote control valve 60 to the bucket open side 60b. Even if it is inadvertently operated, the pilot pressure P2 is prevented from being transmitted to the pilot line L3 side, and the control valve 62 is restricted from switching to the open side 62b. Therefore, the function of the restriction solenoid valve 66 prevents the bucket 18 from being actively operated to the open side regardless of the operation state of the remote control valve 60 during the crane work mode.

  Further, the closing drive solenoid valve 68 is normally located at the position shown in the figure (that is, the position where the pilot pressure Po of the line Lo is blocked from the line L1 side). The closed drive solenoid valve 68 is switched to the other position 68a side by a signal from the output port 59 of the controller 50 when the attachment A is set to the crane work mode. As a result, regardless of the position of the remote control valve 62, the pilot pressure Po of the pilot line Lo is directly transmitted to the close side 62a of the control valve 62 via the check valve 69, and functions to close the bucket 18. . The check valve 69 is inserted for the purpose of preventing the pilot pressure P1 output from the remote control valve 60 to the line L1 from draining through the second solenoid valve 68 during normal operation. It is.

  FIG. 3 shows an outline of the calculation work of the suspension load Wg executed in the controller CL. Since the operation of calculating the suspension load Wg pertains to a known method, only the outline thereof will be described here with reference to FIG.

  In order to calculate the suspension load Wg, information from the pressure sensors 35 and 37 arranged on the boom angle sensor 26, the arm angle sensor 28, the bottom side 34a and the rod side 34b of the boom cylinder 34 is mainly used. Among these signals, the information on the boom angle θ1 and the arm angle θ2 is analog-digital converted by the A / D converters 51 and 52, and then input to the attitude calculation circuit 88, where various information (dimensions) The working radius r and the self-weight moment M of the attachment A are obtained together with the information in the ROM 89 storing the data. On the other hand, in the load calculation circuit 90, the suspension load Wg is calculated based on the information on the calculated working radius r and the own weight moment M and the information on the bottom pressure Pb1 and the rod pressure Pb2 sent from the pressure sensors 35 and 37. Perform the operation. More specifically, this calculation is performed by a method as shown in the lower part of FIG.

  First, the distance calculation block 92 calculates the (vertical) distance D between the swing center (boom foot) 9 of the boom 14 and the boom cylinder 34 based on the boom angle θ1. The thrust calculation block 93 calculates the thrust F of the boom cylinder 34 based on information on the bottom pressure Pb1 and the rod pressure Pb2 of the boom cylinder 34. The obtained distance D and cylinder thrust F are input to the thrust moment calculation block 94, and the thrust moment Mb of the boom cylinder 34 is calculated. The thrust moment Mb is obtained by multiplying the distance D and the cylinder thrust F. Next, in the suspended load moment calculation block 95, the suspended load moment Mw is obtained based on the information on the thrust moment Mb of the boom cylinder 34 obtained in the thrust moment calculation block 94 and the own weight moment M obtained in the posture calculation block 88. It is done. This calculation is performed by subtracting the self-weight moment M from the thrust moment Mb. When the suspended load moment Mw is obtained, the suspended load calculation block 96 calculates the suspended load Wg from the information on the work radius r (obtained by the posture calculation block 88) and the suspended load moment Mw. This calculation is performed by dividing the suspended load moment Mw by the working radius r.

  When the suspension load Wg is thus calculated, the suspension load Wg is compared with the rated load Ws. When the suspension load Wg exceeds the rated load Ws, the buzzer 72 is sounded and a warning lamp ( A warning is issued by turning on or blinking (not shown) to notify the operator that the suspension load Wg is overloaded (alert).

  Generally, in a crane-type hydraulic excavator, the rated load Ws is determined in advance according to the posture of the attachment for each model. Qualitatively, the rated load Ws decreases as the working radius r increases.

  The controller CL discriminates between the excavator work mode and the crane work mode by operating a switch attached to the monitor 70 operated by the operator. Do not execute. On the other hand, when it is determined that the crane work mode is set, the controller CL performs the following predetermined work before entering the calculation of the suspension load Wg. In order to control the core part of the present invention, it will be described in detail below.

  When entering the crane work mode, the operator is required to place the bucket 18 in a fully closed state (cloud state) in advance, but sometimes the crane work mode is entered before the bucket 18 is completely closed. There is. In this case, even if the suspension load Wg and the like are calculated in this state, since these calculations are incorporated on the assumption that the bucket 18 is in a completely closed state, the resulting suspension load Wg is obtained. May not always be an appropriate value. Therefore, the conclusion of “safety” or “overload” determined based on the calculation result is also less reliable.

  Therefore, in this embodiment, as shown in FIG. 1, when it is determined by the operator that the switch attached to the monitor 70 has been changed to the crane work mode (Y in step 80), the output of the bucket angle sensor 29 is output. From this, it is confirmed whether or not the bucket 18 is completely closed (step 82). As a result of the confirmation, when it is determined that the state is not “completely closed”, the routine proceeds to step 84 where the bucket 18 is switched to the closing drive solenoid valve 68 to automatically (force) the fully closed state. Outputs a command. As a result, the state of the closed drive solenoid valve 68 is switched to the other 68a side, and the pilot pressure P0 of the pilot line L0 is directly transmitted to the control valve 62 via the closed drive solenoid valve 68 and the check valve 69. Therefore, the controller valve 62 is switched to the closed side 62a, and the bucket 18 is driven to the closed side. That is, the bucket 18 is always driven in the closing direction regardless of the position of the remote control valve 60 or the function of the regulating solenoid valve 66 at that time.

  At this time, it is even better if an alarm is issued to the effect that the bucket 18 is not currently closed and that it is currently forcibly driven. The alarm is performed by either a warning bell by the buzzer 72, lighting or blinking of a warning lamp provided on the monitor 70, or a combination thereof. That is, if the bucket 18 is not completely closed, the bucket 18 is immediately driven to the fully closed position at that time regardless of the magnitude of the suspension load Wg that is actually being lifted at that time. And an alarm will be generated. As a result, a trouble such as “it is found that the suspended load Wg is actually larger than the predetermined rated load Ws after the suspended load W is lifted” without bothering the operator's hand. It can be surely prevented.

  These determinations and operations are always performed not only immediately after entering the crane operation mode but also during the crane operation mode. This is because even if the crane operation is started with the bucket 18 being completely closed at the beginning, the bucket 18 may be opened due to, for example, hydraulic leakage during a long crane operation. In this embodiment, even in such a case, the worker can be warned promptly that the bucket 18 has started to open.

  It should be noted that the alarm after entering the crane work is not necessarily performed at all times, and may be performed only at predetermined time intervals. In some cases, the alarm after entering the crane operation may be omitted.

  In the present invention, whether or not to design the crane work itself as it is during the work when it is determined that the bucket 18 is not completely closed is not particularly restricted. . If it is designed to stop the crane work itself when the bucket 18 is being closed, a safer work can be performed, but the workability is slightly reduced. In order to obtain a configuration that restricts the crane work itself when the bucket 18 is being closed, for example, the boom cylinder 34 and the arm cylinder 36 that contribute to the crane work correspond to when the condition is satisfied. What is necessary is just to make it not react even if a remote control valve (not shown) is operated. This configuration can be realized by inserting a solenoid valve (not shown) corresponding to the restriction solenoid valve 66 into a hydraulic circuit for driving the boom cylinder 34 and the arm cylinder 36.

The flowchart which shows the control flow performed in the controller of the hydraulic shovel with a crane function to which this invention was applied Main part configuration diagram of hydraulic excavator with crane function Block diagram showing the calculation process of suspension load executed in the controller Front view showing a schematic configuration of a conventional hydraulic excavator with a crane function

Explanation of symbols

A ... Attachment 12 ... Excavator 14 ... Boom 16 ... Arm 18 ... Bucket 26 ... Boom angle sensor 28 ... Arm angle sensor 29 ... Bucket angle sensor 34 ... Boom cylinder 36 ... Arm cylinder 38 ... Bucket cylinder 35, 37 ... Pressure sensor 60 ... Remote control valve 62 ... Control valve 66 ... Regulator solenoid valve 68 ... Closed drive solenoid valve 70 ... Monitor 72 ... Buzzer 74 ... Light CL ... Controller

Claims (4)

In the excavator with a crane function configured to be switchable between an excavation work mode in which the attachment is used for excavation work and a crane work mode in which the attachment is used to lift and move an object,
Means for detecting whether or not the work in the work attachment is in the crane work mode;
Means for detecting whether or not the bucket of the attachment used in the excavation work mode is in a fully closed position;
Means for automatically driving the bucket to the fully closed position when it is detected that the work in the attachment is in the crane work mode and the bucket is not in the fully closed position;
A hydraulic excavator with a crane function. In claim 1,
A crane excavator with a crane function, wherein the crane working mode is detected and whether or not the bucket is in the fully closed position is detected at the moment when the crane working mode is set and every predetermined time thereafter. In claim 1,
A hydraulic excavator with a crane function, wherein the crane work mode is set and whether or not the bucket is in the fully closed position is always detected while the crane work mode is being detected. In any one of Claims 1-3,
When it is detected that the work in the attachment is in the crane work mode and the bucket is not in the fully closed position, the bucket is automatically driven to the fully closed position, and an alarm to that effect is also generated. A hydraulic excavator with a crane function.

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