JP2008286300A - Actuator control device of construction machinery - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To avoid occurrence of a dangerous state due to erroneous switching of a work mode during operation of an actuator in construction machinery equipped with a speed limit function in accordance with the work mode. <P>SOLUTION: Subject to the structure for switching the work mode by a mode switch means 6 and limiting the actuator speed or canceling the limit in accordance with the work mode, presence/absence of lever operation of a remote control valve 3 operating a control valve 4 is detected by pressure sensors 11 and 12, and is input to a controller 13, and switching of speed limiting and limit canceling is not performed during lever operation even when the work mode is switched by the mode switch means 6. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an actuator control device for a construction machine that switches between limiting / releasing actuator speed according to a work mode, such as a so-called high-reach hydraulic excavator having a crane function.

  The background art will be described taking the high reach hydraulic excavator as an example.

  The excavator is provided with mode switching means (switching switch) for switching between a crane work mode in which crane work is performed by a work attachment and a civil work mode in which general civil engineering work such as excavation is performed, and a crane that requires a slow operation In the work mode, the operation speed of the hydraulic actuator (usually the traveling hydraulic motor and the swing hydraulic motor) is limited.

  This speed limitation is generally performed by reducing the engine speed.

  Also, in a shovel that performs so-called load sensing control that controls the pump flow rate so that the difference between the pump pressure and the load pressure is constant, the same speed limitation is performed by limiting the pilot pressure of the remote control valve that operates the control valve. Sometimes (see Patent Document 1).

  FIG. 3 shows a conventional circuit configuration of an actuator control device that performs speed limitation according to such a work mode.

  A case where the crane work mode and the civil work mode are switched will be described as an example.

  As shown in the figure, a hydraulic pump 2 is driven by an engine 1 and pressure oil from the hydraulic pump 2 is supplied to a hydraulic actuator 5 via a hydraulic pilot type control valve 4 operated by a remote control valve 3 as an operating means. Is done. 3a is an operation lever of the remote control valve 3, and T is a tank.

  A switching signal from a mode switching means (switching switch operated by an operator) 6 for switching the work mode is sent to a switchability determination means 8 of a controller 7 as a control means, and when a crane work mode is selected, A speed limit command is sent from the controller 7 to the speed limiter based on the determination by the switchability determination unit 8.

  As speed limiting means, here, first speed limiting means 9 for limiting the engine speed (= pump speed) and secondary pressure by reducing the primary pressure of the remote control valve 3 (the pilot supplied to the control valve 4). The case where two of the second speed limiting means 10 for limiting the maximum pressure = the maximum stroke of the control valve 4 is provided is illustrated.

  Both speed limiting means 9 and 10 perform a speed limiting operation based on a command from the controller 7, whereby the operating speed of the hydraulic actuator 5 is limited in the crane work mode.

  That is, in the crane work mode, the actuator speed relative to the lever operation amount of the remote control valve 3 is lower than in the civil engineering work mode.

On the other hand, when the mode switching means 6 is switched to the civil engineering work mode side, a restriction release signal is sent from the controller 7 to both speed restriction means 9 and 10, and the speed restriction is released.
Japanese Patent Laid-Open No. 11-13548

  However, in the actuator control device having this configuration, the mode switching means 6 may be erroneously operated by the operator in the speed limit state or the limit release state. Alternatively, there may be a case where the above-mentioned erroneous operation is caused by an electrical trouble such as a short circuit of the circuit switching means 6 or the circuit wiring connecting this to the controller 7. Hereinafter, erroneous switching due to erroneous operation and electrical trouble is collectively referred to as erroneous switching.

  If this erroneous switching is performed while the actuator is operating, the actuator will be accelerated or decelerated, and if the lever operation amount is large, the actuator will suddenly increase or decrease speed. During the civil engineering work, the turning speed suddenly changes, the balance of the vehicle body is lost, and the debris piled on the bucket is scattered.

  Accordingly, the present invention provides an actuator control device that can reliably prevent a dangerous situation from occurring due to erroneous switching of a work mode during operation of an actuator in a construction machine having a speed limiting function according to a work mode. is there.

  The invention of claim 1 includes a hydraulic pump, a hydraulic actuator driven by pressure oil from the hydraulic pump, a control valve for controlling the operation of the hydraulic actuator, an operating means for operating the control valve, and a work mode. A mode switching means for switching between a plurality of types, a speed limiting means for limiting the operating speed of the hydraulic actuator, and a speed limit for executing speed limiting by the speed limiting means in response to switching of the work mode by the mode switching means In an actuator control device for a construction machine comprising a control means for switching between a state and a restriction release state for releasing the speed restriction, an operation detection means for detecting presence or absence of operation of the operation means is provided, and the control means Based on the signal from the operation detection means, provided that the operation means is not operated. Those that are configured to permit switching of the speed limit / restriction release.

  According to a second aspect of the present invention, in the configuration of the first aspect, the control means waits for an operation stop of the operating means when the mode switching means is switched during the operation of the operating means, and the speed limit / It is configured to allow switching of restriction release.

  According to a third aspect of the present invention, in the configuration of the first or second aspect, the mode selection means is between a crane work mode in which a crane work is performed by a work attachment and a civil work mode in which a general civil work such as excavation is performed by the work attachment. The switching and control means is configured to be in the speed limit state in the crane mode and in the limit release state in the civil engineering work mode.

  According to a fourth aspect of the present invention, in the configuration of the third aspect, as the hydraulic actuator, a traveling hydraulic motor for traveling the lower traveling body and a turning hydraulic motor for rotating the upper revolving body mounted on the lower traveling body are provided. The speed limiting means is configured to limit at least the operating speed of both the traveling hydraulic motor and the turning hydraulic motor.

  According to the present invention, switching between speed limit / restriction is allowed on condition that the operating means is not operated. In other words, even if there is an erroneous operation of the mode switching means or an electrical trouble, if the actuator is operating (during operation of the operating means), the speed limit / cancel release will not be switched, and the machine movement will increase rapidly. There is no risk of dangerous situations due to speed or sudden deceleration, and safety is achieved.

  By the way, in the present invention, when mode switching is performed during operation of the actuator, the mode switching operation itself can be invalidated and the processing can be terminated. However, in this case, there is an inconvenience that the mode switching operation must be performed again after the operation is stopped when the mode switching is the operator's intention and the operation time is just too early.

  In this respect, according to the second aspect of the invention, since the mode switching is suspended and the operation is stopped and executed, the troublesomeness of the re-operation can be eliminated.

  According to the invention of claim 3, if there is a sudden deceleration or a sudden increase of the actuator (especially, traveling or turning of claim 4) due to erroneous switching in a machine that switches between the crane work mode and the civil engineering work mode, as described above. In addition, it is easy to fall into a dangerous situation such as swinging of cargo or scattering of debris, so it is highly effective in improving work safety.

  An embodiment of the present invention will be described with reference to FIGS.

  FIG. 1 shows a circuit configuration of an actuator control apparatus according to the embodiment. In the figure, the same parts as those in the known technique shown in FIG.

In this device,
(I) The hydraulic pump 2 is driven by the engine 1, and the pressure oil from the hydraulic pump 2 is supplied to the hydraulic actuator 5 via a hydraulic pilot type control valve 4 operated by a remote control valve 3 as an operating means. Point
(Ii) A switching signal from a mode switching means (switching switch operated by an operator) 6 for switching the work mode is sent to a switchability determination means 15 of a controller 13 as a control means, and basically a crane work mode. Is selected, a speed limit command is sent from the controller 13 to the speed limiter based on the determination of the switchability determination unit 15;
(Iii) As speed limiting means, first speed limiting means 9 for limiting the engine speed (= pump speed) and secondary pressure by reducing the primary pressure of the remote control valve 3 (pilot supplied to the control valve 4) The second speed limiting means 10 for limiting the maximum pressure = the maximum stroke of the control valve 4),
(Iv) The speed limit operation of the hydraulic actuator 5 is limited in the crane work mode by the speed limit operation of both the speed limit means 9 and 10 based on the command from the controller 13;
(V) When the mode switching means 6 is switched to the civil engineering work mode side, a restriction release signal is sent from the controller 13 to both speed restriction means 9 and 10, and the speed restriction is released. The same.

  In this embodiment, the secondary pressure of the remote control valve 3 (pilot pressure supplied to the pilot ports on both sides of the control valve 4) is used as operation detection means for detecting whether or not the remote control valve 3 is operated (hereinafter referred to as lever operation). Are provided, and signals from the pressure sensors 11 and 12 are sent to the controller 13.

  The controller 13 receives the sensor signal and determines whether or not the lever is operated. Based on the determination by the lever 14 and the switching signal from the mode switching means 6 based on the determination by the means 14 and the switching signal from the mode switching means 6. A switchability determination means 15 for making a determination is provided, and speed limit / restriction release by the first and second speed limiters 9, 10 is controlled based on a command from the switchability determination means 15.

  More specifically, even if mode switching (including erroneous switching) is performed, if the lever is being operated (actuator is operating), switching between speed limit / restriction is not executed.

  The operation of this point will be described with reference to the flowchart of FIG.

  When the control is started, it is determined whether or not the mode has been switched in step S1. If NO (the mode has not been switched), the process ends. If YES (the mode has been switched), the process proceeds to step S2.

  In step S2, it is determined whether or not there is a lever operation. Only when there is no lever operation (NO), the process proceeds to step S3 and it is determined whether or not the speed is being limited.

  If the speed is already being limited, the speed limit is canceled in step S5. If the speed is not limited, the speed limit is executed in step S4.

  On the other hand, if YES in step S2, that is, if it is determined that there is a lever operation, step S2 is not performed, and step S2 is repeated until the operation turns without lever operation.

  In other words, the speed limit / release switching associated with the mode switching is executed after the lever operation is stopped (lever neutral).

  Therefore, even if an erroneous mode change is performed due to an erroneous operation of the mode switching means 6 or a short circuit wiring, etc., switching of speed limit / restriction is allowed if the actuator is operating (during lever operation). Not.

  For this reason, it is possible to increase the safety of work by avoiding the occurrence of dangerous situations such as load swinging due to erroneous switching during crane work (during speed limit) or scattering of debris due to erroneous switching during civil engineering work. it can.

  In addition, when the mode is switched during the lever operation (YES in step S2), this mode switching is suspended, and is executed after waiting for the lever operation to stop (transition to step S3). Therefore, when the operation timing is just too early, it is possible to eliminate the troublesomeness of having to redo the mode switching operation after stopping the operation.

Other Embodiments (1) The controller 13 is provided with a timer, and it is determined between steps S2 and S3 in FIG. 2 whether or not the state of no lever operation has continued for a certain period of time. Good.

  In this way, when the lever 3a of the remote control valve 3 is only momentarily returned to the neutral position as when the lever 3a is operated on the opposite side, the speed limit / restriction release is not switched, so the control is not performed. Stabilize.

  (2) As a detection method for detecting the lever operation, a method for detecting the movement of the lever 3a by a limit switch or the like instead of the method for detecting the secondary pressure of the remote control valve by the pressure sensors 11 and 12 in the above embodiment, or a load A system for detecting the movement of the load sensing valve device may be employed in the circuit configuration for performing the sensing control.

  (3) In the above embodiment, the first speed limiting means 9 for limiting the engine speed and the second speed limiting means 10 for limiting the primary pressure of the remote control valve 3 are used as the speed limiting means. Only one of these may be used. Or what restrict | limits the maximum value of the secondary pressure of the remote control valve 3 may be employ | adopted.

  (4) The present invention is particularly effective when applied to a high-reach type hydraulic excavator that switches between a crane work mode and a civil engineering work mode as in the above-described embodiment. The present invention can be widely applied to construction machines that perform speed restriction / restriction according to mode switching.

It is a circuit block diagram of the actuator control apparatus concerning embodiment of this invention. It is a flowchart for demonstrating the effect | action of the apparatus. It is a conventional circuit block diagram.

Explanation of symbols

DESCRIPTION OF SYMBOLS 2 Hydraulic pump 3 Remote control valve as operation means 3a Lever 4 Control valve 5 Hydraulic actuator 6 Mode switching means 9 1st speed limiting means 10 2nd speed limiting means 11, 12 Pressure sensor as operation detection means 13 Controller as control means 14 Controller lever operation presence / absence judging means 15 Controller switching possibility judging means

Claims (4)

  A hydraulic pump, a hydraulic actuator driven by pressure oil from the hydraulic pump, a control valve for controlling the operation of the hydraulic actuator, an operating means for operating the control valve, and a work mode are switched between a plurality of types. A mode switching unit, a speed limiting unit for limiting the operating speed of the hydraulic actuator, and a speed limiting state and a speed limit for executing the speed limitation by the speed limiting unit according to the switching of the work mode by the mode switching unit. In an actuator control apparatus for a construction machine having a control means for switching to a restriction release state, an operation detection means for detecting the presence or absence of an operation of the operation means is provided, and the control means receives a signal from the operation detection means. Based on the condition that the operating means is not operated. Actuator control system for a construction machine characterized in that it is configured to permit switching of release.   The control means is configured to allow the speed limit / restriction change to wait after the operation means is stopped when the operation mode is switched by the mode switching means during operation of the operation means. The construction machine actuator control device according to claim 1, wherein:   The mode selection means is switched between a crane work mode in which crane work is performed by the work attachment and a civil work mode in which general civil work such as excavation is performed by the work attachment, and the control means is in a speed limited state in the crane mode, The actuator control device for a construction machine according to claim 1 or 2, characterized in that the restriction is released in a civil engineering work mode.   The hydraulic actuator includes a traveling hydraulic motor that travels the lower traveling body, and a turning hydraulic motor that swings the upper swinging body mounted on the lower traveling body, and the speed limiting means includes at least both the traveling and the turning motors. 4. The construction machine actuator control device according to claim 3, wherein the operation speed of the hydraulic motor is limited.

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