JP2008240878A - Control device for working machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a control device for a working machine capable of determining whether or not pressurized oil has been supplied to a control valve without adding a component such as a pressure sensor. <P>SOLUTION: This control device is used for a working machine equipped with an acceleration cylinder 59 for operating actuators 5, 8, 9, 10 at a desired speed with a hydraulic pump 17 driven by an engine 15 of the vehicle as a hydraulic pressure source. The acceleration cylinder 50 is adapted to a working machine having a position detector 53 for detecting a position according to its operation amount, and includes a controller 30 for controlling a control valve 20 that operates the actuators 5, 8, 9, 10. The controller 30 operates only the acceleration cylinder 50 temporarily, and based on a signal from the position detector 53 of the acceleration cylinder 50, determines whether or not the control valve 20 is in a state of being supplied with pressurized oil. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a work machine control device used for a work machine such as a cargo handling machine, a construction machine, or a civil engineering machine mounted on a vehicle.

As a work machine mounted on a vehicle, for example, a vehicle-mounted crane is known (see, for example, Patent Document 1).
This type of crane includes a hydraulic pump and a plurality of actuators using the hydraulic pump as a hydraulic source. The hydraulic pump uses a vehicle engine as a power source and operates via a PTO (power take-off) connected to the vehicle engine. The pressure oil discharged from the hydraulic pump is supplied to the main pipeline, which is connected to a control valve (switching control valve device) of the crane body, and the return pipeline of the control valve is connected to the tank. An unloading valve is interposed in the middle part of the main pipeline. Furthermore, the control valve is connected to the control device of the crane body via a signal line. The control device has a controller that controls the control valve.

  Here, the control valve includes a plurality of indirect drive switching valves for driving the crane actuators, and an accelerator cylinder for opening and closing the vehicle accelerator and operating the crane actuators at a desired speed. And have. In addition, each switching valve and the accelerator cylinder are switched in accordance with a predetermined control signal input from the controller of the control device so that the pressure oil discharged from the hydraulic pump is appropriately supplied and discharged. ing. Each switching valve and the accelerator cylinder are configured with a proportional solenoid, and the position of the plunger in the axial direction is controlled proportionally.

When starting crane work with this type of crane, after starting the engine of the vehicle, the clutch of the vehicle is first disengaged and then the PTO is turned on. When the PTO is turned on, electric power is supplied from the vehicle to the control device of the crane body, and simultaneously with the clutch being connected, the hydraulic pump starts rotating and pressure oil is supplied to the control valve.
However, if any proportional solenoid of the control valve is stuck in a mechanically open state, the pilot pressure required to drive the switching valve is supplied to the piston chamber of the spool of the switching valve. End up. Therefore, there is a possibility that the spool moves without permission and the crane malfunctions.

Therefore, in order to prevent such a malfunction, the controller of the control device that controls the control valve is configured to include a valve abnormality detecting means that detects whether or not the control valve is abnormal.
This valve abnormality detection means checks whether or not all the spools are in the neutral position for about 3 seconds after the PTO is turned on by using the position detector of each spool, and any of the spools is neutral even once during the check. If it is detected that the valve has moved out of the range to be set, it is determined that the proportional solenoid is abnormal, the unload valve is driven, and the unload state is maintained until the power is turned on again. It has become. The plurality of switching valves have a position detector on each spool, but the proportional solenoid does not have such a position detector. Therefore, the controller indirectly determines whether or not there is an abnormality in the proportional solenoid by the movement of the position detector of each spool.
JP 2003-252569 A

  Incidentally, since the plurality of switching valves constituting the control valve are indirect drive systems, pilot pressure is required to move the spool. For this reason, when the proportional solenoid is checked, the control valve must be supplied with pressure oil. Here, although electric power is supplied immediately after the PTO is turned on, there is a time lag until the hydraulic pump is driven and pressure oil is supplied to the control valve. Therefore, conventionally, as described above, a time lag is dealt with by setting a check time of about 3 seconds after the PTO is introduced.

However, in recent years, an increasing number of vehicles have a relatively long time lag that takes more than 3 seconds. Therefore, when a crane is mounted on a vehicle with such a long time lag, even if the proportional solenoid is caught in an open state, the controller cannot detect this as an abnormality.
That is, when the PTO is turned on, power is supplied to the control device, whereby the controller in the control device executes the valve abnormality detection means and starts checking whether all the spools are in the neutral position. To do. At this time, immediately after the start of the check, even if the proportional solenoid is in an open state, the pressure oil is not yet supplied because of the time lag. Therefore, immediately after the start of the check, the spool remains in the neutral position and no abnormality is detected. Next, when the state in which pressure oil is not supplied as it is for 3 seconds elapses, the controller stops checking by the valve abnormality detection means and enters a state of waiting for manual or remote operation. Therefore, after that, if pressure oil is supplied to the control valve after 3 seconds or more have elapsed due to the time lag, the pilot pressure is supplied to the proportional solenoid that is caught in the open state.

  However, since the check by the valve abnormality detecting means has already been completed, the abnormality of the proportional solenoid is not detected, and the unload valve is not driven. Therefore, the spool starts to move on its own, resulting in a malfunction of the crane. As described above, in order to reliably detect the abnormality of the proportional solenoid, it is necessary to always supply the pressure oil to the control valve during the spool check when the PTO is turned on.

  Therefore, as a means for preventing the abnormality of the proportional solenoid from being detected due to the time lag from when power is supplied to when pressure oil is supplied as described above, for example, whether pressure oil is supplied. It is conceivable to add a pressure sensor (pressure switch or the like) for detecting whether or not. If such a pressure sensor is provided, it is possible to detect that the pressure oil has been supplied and to have a check time further from the time of detection, so it is possible to reliably detect an abnormality in the proportional solenoid. However, in the method of providing such a pressure sensor, it is necessary to add a part called a pressure sensor, and the signal of the pressure sensor must be taken into the controller. Therefore, an input port for the pressure sensor is added to the controller. There is a problem of having to.

  Further, as another measure, in order to deal with a vehicle with a long time lag as described above, for example, a measure in which the check time by the valve abnormality detection means is extended (for example, 6 seconds) can be considered. However, simply extending the check time is not preferable because the waiting time of the operator at the start becomes longer, and it is not preferable that the pressure oil is supplied. It is not sufficient to reliably detect the presence or absence of abnormalities.

  Therefore, the present invention has been made paying attention to such a problem, and it is possible to determine whether or not the pressure oil is supplied to the control valve without adding parts such as a pressure sensor. It is an object to provide a control device for a vehicle. It is another object of the present invention to provide a work machine control device that can reliably detect abnormality of a control valve.

  In order to solve the above-described problems, a first invention of the present invention is a hydraulic pump driven by a vehicle engine, a plurality of actuators using the hydraulic pump as a hydraulic source, and the plurality of actuators at a desired speed. And a control valve having a plurality of switching valves for supplying and discharging pressure oil for operating each of the plurality of actuators, and the accelerator cylinder according to the operation amount A control device used in a work machine having a position detector for detecting a position and having a controller for controlling the control valve, wherein the controller is in a state where pressure oil is supplied to the control valve. Pressure oil supply state determination means for determining whether or not the pressure oil supply state determination means Only once actuate the Sunda, based on a signal from the position detector of the accelerator cylinder, pressure oil to the control valve is characterized by determining whether a state of being supplied.

  According to the control device for a work machine according to the first invention, the controller includes the pressure oil supply state determination unit, and the pressure oil supply state determination unit temporarily operates only the accelerator cylinder, and the position of the accelerator cylinder is determined. Since it is determined whether or not pressure oil is supplied to the oil passage based on the signal from the detector, whether or not pressure oil is supplied to the control valve without adding a part such as a pressure sensor. Can be determined.

  Further, the second invention of the present invention is the work machine control device according to the first invention, wherein each of the plurality of switching valves has a position detector for detecting a position according to the operation amount, The controller includes valve abnormality detection means for detecting whether or not the control valve is abnormal, and the valve abnormality detection means determines that pressure oil has been supplied to the control valve by the pressure oil supply state determination means. Thereafter, the presence or absence of abnormality of the control valve is detected based on signals from position detectors provided in the plurality of switching valves.

  According to the work machine control device related to the second invention, the valve abnormality detection means is provided with a plurality of switching valves after the pressure oil supply state determination means determines that the pressure oil is supplied to the control valve. Since the presence or absence of abnormality of the control valve is detected based on the signal from the detector, it is possible to reliably detect that the pressure oil has been supplied to the control valve, and to have a check time from the time of detection. Therefore, since the check is started after reliably detecting the pressure oil supplied to the control valve, the reliability of the check can be improved. Further, when detecting an abnormality of each switching valve, the check time can be shortened within a necessary and sufficient range. Accordingly, for example, the waiting time of the operator at the time of activation can be shortened as compared with the case where the check time is simply extended to cope with the time lag.

  As described above, according to the present invention, it is possible to provide a work machine control device that can determine whether or not pressure oil is supplied to a control valve without adding components such as a pressure sensor. In addition, it is possible to provide a work machine control device capable of reliably detecting an abnormality of the control valve.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings as appropriate. FIG. 1 is a configuration diagram illustrating a vehicle-mounted crane as an embodiment of a work machine mounted on a vehicle according to the present invention, and FIG. 2 is an embodiment of a work machine control device according to the present invention. It is a block diagram explaining the control apparatus of a vehicle-mounted crane which is.
As shown in FIG. 1, in this vehicle-mounted crane 1, a column 6 is pivotably provided on a base 4 having an outrigger 2, and a boom 7 that expands and contracts at the upper end portion of the column 6 is pivotally supported. Has been. A winch 11 is provided in the column 6, and a wire rope 12 is led from the winch 11 to the tip of the boom 7, and is attached to a hook 13 for a suspended load via a pulley (not shown) at the tip of the boom 7. By hooking, the hook 13 is suspended from the tip of the boom 7.

Here, the crane 1 includes a swing hydraulic motor 5 and a boom hoisting hydraulic cylinder as a plurality of actuators for rotating the column 6, raising and lowering and extending and retracting the boom 7, and winding and unwinding the winch 11. 9, a boom expansion / contraction hydraulic cylinder 8, a winch hydraulic motor 10, and outrigger hydraulic cylinders 3L and 3R.
As shown in FIG. 2, the swing hydraulic motor 5, the boom hoisting hydraulic cylinder 9, the boom telescopic hydraulic cylinder 8, the winch hydraulic motor 10, and the outrigger hydraulic cylinders 3L and 3R are all vehicles. The hydraulic pump 17 driven by being connected to the PTO 16 of the engine 15 is operated by supplying pressure oil through the control valve 20. Between the pump port and the tank port, there are provided a main relief valve 38 and an unload valve 39 that opens the main relief valve 38 when unloading is necessary, and communicates the pump port with the tank port. Yes.

  Here, the control valve 20 is a multi-connecting valve device configured by connecting a plurality of switching valves for controlling the actuators. As shown in the figure, the swing hydraulic motor 5 and the boom hoisting hydraulic pressure are provided. A plurality of switching valves 31, 32, 33, 34 corresponding to the actuators of the cylinder 9, the boom telescopic hydraulic cylinder 8, and the winch hydraulic motor 10, and the actuators of the outrigger hydraulic cylinders 3L, 3R, respectively. A plurality of corresponding switching valves 28 and 29 and an accelerator cylinder 50 for operating each actuator at a desired speed are provided.

  Specifically, as shown in an enlarged view in FIG. 3, a main spool 36 is built in each switching valve 31, 32, 33, 34 of the control valve 20. The main spool 36 is normally held at a neutral position by left and right springs 36s. One end of the main spool 36 is connected to the operating lever 18 via a link 18r, and a pilot piston 37 is connected to the other end. An iron core 23 is provided at the tip of the piston rod 22. ing. The iron core 23 is inserted into a position detector 40 having a hollow cylindrical differential transformer. The position detector 40 detects the displacement of each main spool 36 and feeds back the detected displacement signal to the controller 30.

  Each switching valve 31, 32, 33, 34 is provided with a proportional solenoid (proportional electromagnetic pilot valve) 41 having a pair of solenoids 42L, 42R. Each proportional solenoid 41 has a port E to which pilot pressure oil is supplied from the hydraulic pump 17 via the pressure reducing valve 35 is normally closed, and a port F for returning the hydraulic oil to the tank 14 is normally open. When a control current is input to 42L and 42R, the pilot spool 42s slides, and the opening amount of the port E is controlled by the input current value. Thereby, the supply of pilot pressure oil to the left and right oil chambers 37L, 37R of the pilot piston 37 is controlled.

  When the pilot pressure oil is supplied to either one of the oil chambers 37R and 37L of the pilot piston 37, the main spool 36 moves to the left or right, and the switching valves 31, 32, 33, and 34 The ports A and B and the pump port P are communicated. As a result, the switching valves 31, 32, 33, and 34 operate the actuators of the swing hydraulic motor 5, the boom hoisting hydraulic cylinder 9, the boom telescopic hydraulic cylinder 8, and the winch hydraulic motor 10 described above. It has become. Note that the actuators of the swing hydraulic motor 5, the boom hoisting hydraulic cylinder 9, the boom telescopic hydraulic cylinder 8, and the winch hydraulic motor 10 are controlled by the controller 30 so as to interlock with each other according to the work contents of the crane 1. Be controlled. For example, when the boom 7 is extended while the distance between the tip of the boom 7 and the hook 13 is kept constant, the lowering operation of the winch 11 is also required as the boom 7 is extended. The hydraulic cylinder 8 and the winch hydraulic motor 10 are interlocked.

The switching valves 28 and 29 for driving the outrigger hydraulic cylinders 3L and 3R also have a position detector 40, which detects the displacement of each spool and feeds back the detected displacement signal to the controller 30. It is supposed to be.
On the other hand, as shown in an enlarged view in FIG. 4, the accelerator cylinder 50 is also provided with a proportional solenoid (proportional electromagnetic pilot valve) 51. Also for this proportional solenoid 51, the port E to which the pilot pressure oil is supplied is normally closed, and the port F for returning the hydraulic oil to the tank 14 is normally open. When the control current is input from the controller 30, the pilot spool 51s And the opening amount of the port E is controlled by the input current value. Thereby, the supply of the pilot pressure oil to the oil chamber 52s of the main spool 52 is controlled.

  The accelerator cylinder 50 is also provided with a position detector 53 for detecting the displacement of the main spool 52 and feeding it back to the controller 30 of the control device. Then, the controller 30 obtains the accelerator operation amount based on the selection of the actuator by the operation lever 18 or the remote controller 19 and the operation amount, etc., and outputs a necessary accelerator control signal to the proportional solenoid 51 of the accelerator cylinder 50. 50 is actuated. Further, the position detector 53 of the accelerator cylinder 50 feeds back the detected value to the controller 30, and the controller 30 performs necessary correction if there is an excess or deficiency. Note that the discharge amount of the pressure oil from the hydraulic pump 17 increases as the rotational speed of the engine 15 is increased by the accelerator operation.

Next, the controller 30 will be described in more detail.
The controller 30 of this control device stores a CPU control program and the like in advance in a predetermined area, a CPU for controlling the entire system of the vehicle-mounted crane 1 based on a predetermined control program (not shown). Data for external devices including the read-out ROM, the data read from the ROM, the RAM for storing the calculation results necessary for the calculation process of the CPU, and the remote controller 19 of the on-vehicle crane 1 And an I / F (interface) that mediates the input / output. These are connected to each other via a bus which is a signal line for transferring data so that data can be exchanged. And from the remote controller 19, the predetermined operation signal used as the execution command which operates each actuator of the crane 1 is input by switch operation by an operator.

  Here, the controller 30 executes a valve abnormality detection process for detecting whether or not the control valve 20 is abnormal after the operator starts the engine of the vehicle, and the main spool 36 of each switching valve 31, 32, 33, 34 is detected. Whether or not each of the proportional solenoids 41 is abnormal is determined based on the movement of the position detector 40, thereby preventing a malfunction of the crane.

Hereinafter, the valve abnormality detection process in the controller 30 will be described in detail. FIG. 5 is a flowchart of the valve abnormality detection process executed by the controller 30.
In this vehicle-mounted crane 1, when an operator starts the engine 15 of the vehicle and then turns off the clutch of the vehicle and then turns on the PTO 16, power is supplied from the vehicle to the control device of the crane body. The valve abnormality detection process shown in the figure is executed in the CPU, and first, the process proceeds to step S1.

  In step S1, the switching valves 31, 32, 33, 34 including the main spool 52 of the accelerator cylinder 50, and all the spools of the switching valves 28, 29 (the turning hydraulic motor 5, the boom raising hydraulic cylinder 9, the boom extending / contracting). Check whether the main spool 36 of the switching valve corresponding to each of the hydraulic cylinder 8 and the winch hydraulic motor 10 and the spool of the switching valve corresponding to the outrigger hydraulic cylinders 3L and 3R) is in the neutral position. If even one of them is not in the neutral position, the process proceeds to step S2, and if all the spools are in the neutral position, the process proceeds to step S3.

In step S2, it is determined that there is an abnormality in the control valve 20, and the unload valve 39 is driven to open the main relief valve 38, whereby an unload state is established in which the pump port and the tank port are in communication. Thereafter, the unload state is maintained until the power is turned on again (abnormal end).
In step S3, only the check of the main spool 52 of the accelerator cylinder 50 is canceled and the process proceeds to step S4. In step S4, a signal is output to the proportional solenoid 51 for the accelerator cylinder, and the process proceeds to step S5. Even if a signal is output to the proportional solenoid 51, the pressure oil is not immediately supplied due to the time lag, so the accelerator cylinder 50 does not immediately move at the time of step S4.

  In step S5, based on the displacement signal of the main spool 52 by the position detector 53 of the accelerator cylinder 50, it is determined whether or not the main spool 52 has exceeded the neutral position range. That is, it is determined whether or not the pressure oil has been supplied to the oil passage through the time lag. If the main spool 52 does not exceed the neutral position range (no pressure oil is supplied to the oil passage), the process proceeds to step S3. When the process is returned and the main spool 52 exceeds the range of the neutral position (pressure oil is supplied to the oil passage), the process proceeds to step S6.

  In step S6, output of the signal to the proportional solenoid 51 for the accelerator cylinder is stopped, and the process proceeds to step S7. In step S7, the unload valve 39 is driven to enter the unload state, and the process proceeds to step S8. Here, the reason why the unload valve 39 is driven in step S7 is that even if the proportional solenoid 51 of the accelerator cylinder 50 is caught in a mechanically open state at this time, the return spring of the accelerator cylinder 50 is returned. This is to reliably return the accelerator cylinder 50 to the neutral position.

  In step S8, it is determined whether or not the main spool 52 of the accelerator cylinder 50 has returned to the neutral position range. If the main spool 52 has returned to the neutral position range, the process proceeds to step S9. If the main spool 52 has not returned to the neutral position range, the process returns to step S6. In step S9, the driving of the unload valve 39 is stopped, the unload state is canceled and the process proceeds to step S10. In step S10, the check timer is reset (Timer = 0), and the process proceeds to step S11.

In step S11, it is checked whether or not all the switching valves 31, 32, 33, 34 including the main spool 52 of the accelerator cylinder 50 and all the spools of the switching valves 28, 29 are in the neutral position. If it is not in the neutral position, the process proceeds to step S2, and if all the spools are in the neutral position, the process proceeds to step S12.
In step S12, it is determined whether or not a predetermined set time (for example, 3 seconds) has elapsed. If the set time has elapsed, the process proceeds to step S13, and if not, the process returns to step S11. In step S13, since all the spools are in the neutral position at a predetermined set time, it is determined that there is no abnormality in the control valve 20, the valve abnormality detection process is terminated (normal termination), and the process is returned. Therefore, it is in a state of waiting for operation of a manual or remote controller. Here, steps S1 to S13 shown in the flowchart of the valve abnormality detection process correspond to the valve abnormality detection means, and steps S3 to S9 among them correspond to the pressure oil supply state determination means.

  Next, operations and effects of the control device for the vehicle-mounted crane 1 will be described with reference to FIGS. 6 to 11 as appropriate. FIG. 6 is a timing chart relating to valve abnormality detection processing in the controller 30. 7 and 8 are longitudinal sectional views of the accelerator cylinder 50. FIG. 7 shows a state in which a control signal is output to the proportional solenoid, but no pressure oil is supplied. FIG. A control signal is output and pressure oil is supplied. 9 to 11 are longitudinal sectional views of the switching valves 31 and (32, 33, 34). FIG. 9 shows a state in which no pressure oil is supplied when the proportional solenoid is caught. 10 shows a malfunction state in which pressure oil is supplied when the proportional solenoid is caught. FIG. 11 shows a normal operation state in which a control signal is output to the proportional solenoid and pressure oil is supplied. Is shown.

  As described above, when the operator starts the engine 15 of the vehicle and then turns on the PTO 16 after turning off the clutch of the vehicle, the controller 30 of the control device supplies power to the control device of the crane body from the vehicle. Then, the valve abnormality detection process is executed, and it is first checked whether or not all the spools including the accelerator cylinder 50 are in the neutral position (step S1). Then, the controller 30 determines that it is abnormal if any one of the spools is not in the neutral position range by this check, and drives the unload valve 39 (step S2). When starting work, immediately after starting the engine of the vehicle, if any proportional solenoid of the control valve 20 is caught in a mechanically open state, a malfunction of the crane caused by the spool moving freely Can be prevented.

  Here, the check immediately after the PTO 16 is input is in the range (time) indicated by the symbol a in FIG. That is, although the electric power is supplied immediately after the PTO 16 is turned on, the range (time) indicated by the symbols a and b in FIG. 6 until the hydraulic pump 17 is driven and the pressure oil is supplied to the control valve 20. ), There is a time lag until the hydraulic pressure is raised, and the check is made in a state where the hydraulic pressure is not raised. Therefore, as shown in FIG. 9, if the proportional solenoid 41 is caught in any one of the switching valves 31, (32, 33, 34), when the pressure oil is not supplied, the main spool 36. If is in the neutral position range, it is not determined that the proportional solenoid is caught. Therefore, when pressure oil is supplied thereafter, as shown in FIG. 10, the main spool 36 operates and the crane malfunctions even though no control signal is output.

  Therefore, in the valve abnormality detection process executed by the controller 30, if all spools including the accelerator cylinder 50 are neutral after the check immediately after the PTO 16 is turned on, only the check of the main spool 52 of the accelerator cylinder 50 is canceled. Further, by outputting a signal to the proportional solenoid 51 for the accelerator cylinder, only the accelerator cylinder 50 is temporarily operated (step S4), and the displacement of the main spool 52 by the position detector 53 of the accelerator cylinder 50 is detected. Based on this signal, it is determined whether or not the main spool 52 exceeds the neutral position range (step S5).

  Accordingly, as shown in FIG. 4, in the accelerator cylinder 50, since no control signal is initially output to the proportional solenoid 51, the main spool 52 is positioned at the initial position, and the position detector 53 is positioned at the initial position. The corresponding displacement signal is output. Next, when a control signal is output to the proportional solenoid 51, the pilot spool 51s slides, but the main spool 52 does not move until pressure oil is supplied as shown in FIG. Accordingly, the displacement signal from the position detector 53 does not change. On the other hand, when the pressure oil is supplied to the oil passage after the time lag, the pressure oil is supplied from the port E to the oil chamber 52s of the main spool 52, whereby the main spool 52 slides as shown in FIG. Therefore, a displacement signal is output from the position detector 53 in accordance with the displacement. Therefore, the controller 30 can determine whether or not the pressure oil is supplied to the control valve 20 by monitoring the change in the signal from the position detector 53. Although the accelerator cylinder 50 is once operated, there is no safety problem because the crane itself does not move even if the accelerator cylinder 50 is operated.

  That is, according to the controller 30, the pressure oil supply state determination unit is provided. The pressure oil supply state determination unit temporarily operates only the accelerator cylinder 50, and from the position detector 53 of the accelerator cylinder 50. Since it is determined whether or not the pressure oil is supplied to the oil passage based on the signal, for example, it is determined whether or not the pressure oil is supplied to the control valve 20 without adding a part such as a pressure sensor. can do. In step S5, when the signal from the position detector 53 does not exceed the range of the initial position (until the range (time) indicated by symbol c in FIG. 6 is reached), the process returns to step S3. Therefore, during the time lag, it waits in this step, and thereafter, when the pressure oil is supplied from the hydraulic pump 17 to the control valve 20, the accelerator cylinder 50 starts to move, so that after the pressure oil is reliably supplied to the control valve 20, Move on to the next step.

  Next, the controller 30 stops the output to the proportional solenoid 51 when the amount of movement of the accelerator cylinder 50 is out of the initial range (step S6), and further drives the unload valve 39 to unload. A state is set (step S7). Therefore, since the output of the proportional solenoid 51 is stopped and the unload valve 39 is also driven, the accelerator cylinder 50 is spring-loaded and the main spool 52 is returned to the initial position (the range (time indicated by the symbol d in FIG. 6) )). Thus, even if the proportional solenoid 51 of the accelerator cylinder 50 is caught in a mechanically open state, the main spool 52 of the accelerator cylinder 50 is reliably returned to the initial position by the return spring of the accelerator cylinder 50. (Steps S6 to S8).

  Next, when the accelerator cylinder 50 returns to the initial position, the controller 30 stops driving the unload valve 39 (step S9), and then the set time (range (time) indicated by reference sign e in FIG. 6). Then, for example, for 3 seconds, all spools including the main spool 52 of the accelerator cylinder 50 are checked again (steps S11 and S12). If all the spools are within the neutral position (or the initial position, the same applies hereinafter) during the set time, the check ends (normally ends) (step S13), and the operation waits for manual operation or remote operation. It becomes. If any of the spools exceeds the neutral position range, the unload valve 39 is driven to complete the unloading state and terminate the check (abnormal termination) (step S2), so the spool moves freely. Therefore, it is possible to reliably prevent the malfunction of the crane.

  That is, according to the controller 30 of this control device, it is possible to confirm whether or not pressure oil has been supplied to the control valve 20 without adding components such as a pressure sensor, so there is no need to add components such as a pressure sensor. In addition, there is no need to separately acquire a signal from the pressure sensor or the like in the controller. Therefore, it is not necessary to add an input port for the pressure sensor to the controller. Since all proportional solenoids including the accelerator cylinder 50 are checked after the pressure oil is supplied, the abnormality of the control valve 20 can be reliably detected.

  Furthermore, since it is reliably detected that pressure oil has been supplied to the control valve 20 and a check time is provided from the time of detection, the reliability of the check can be further improved. Further, when detecting an abnormality in each of the switching valves 31, 32, 33, 34, etc., the check time can be shortened within a necessary and sufficient range. Therefore, for example, the waiting time of the operator at the time of activation can be shortened as compared with the case where the check time is simply extended to cope with the time lag until the pressure oil rises.

The control device according to the present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention.
For example, in the above embodiment, a vehicle-mounted crane has been described as an example of a working machine mounted on a vehicle according to the present invention. However, the present invention is not limited thereto, and the working machine according to the present invention is mounted. In addition, the vehicle can be applied to a crane vehicle, an aerial work vehicle, a wheel loader, a power shovel, or the like.

It is a block diagram explaining the vehicle-mounted crane as one Embodiment of the working machine mounted in the vehicle which concerns on this invention. It is a block diagram explaining the control apparatus of the vehicle-mounted crane which is one Embodiment of the control apparatus for work machines which concerns on this invention. It is a longitudinal cross-sectional view containing the axis line of a switching valve, The figure has shown the state located in the neutral position where the control signal is not output to the proportional solenoid. It is a longitudinal cross-sectional view containing the axis line of an accelerator cylinder, The figure has shown the state located in the initial position where the control signal is not output to the proportional solenoid. It is a flowchart of the valve abnormality detection process performed with a controller. It is a timing chart which concerns on the valve abnormality detection process in a controller. It is a longitudinal cross-sectional view of an accelerator cylinder, and the figure shows a state in which a control signal is output to the proportional solenoid but no pressure oil is supplied. It is a longitudinal cross-sectional view of an accelerator cylinder, and the figure shows a state where a control signal is output to a proportional solenoid and pressure oil is supplied. It is a longitudinal cross-sectional view of a switching valve, The figure has shown the state by which pressure oil is not supplied, when a proportional solenoid is hooked. It is a longitudinal cross-sectional view of a switching valve, The figure has shown the state of the malfunction by which pressure oil was supplied when the proportional solenoid was caught. It is a longitudinal cross-sectional view of a switching valve, and shows the state of normal operation in which a control signal is output to a proportional solenoid and pressure oil is supplied.

Explanation of symbols

1 Vehicle-mounted crane (work machine)
2 Outrigger 3L, 3R Outrigger hydraulic cylinder (actuator)
4 Base 5 Turning hydraulic motor (actuator)
6 Column 7 Boom 8 Boom telescopic hydraulic cylinder (actuator)
9 Boom hydraulic cylinder (actuator)
10 Hydraulic motor (actuator) for winch
11 Winch 12 Wire rope 13 Hook 14 Tank 15 Engine 16 PTO
17 Hydraulic pump 18 Operating lever 19 Remote controller 20 Control valve 22 Piston rod 23 Iron core 28, 29 (For outrigger) switching valve 30 Controller 31, 32, 33, 34 Switching valve 35 Pressure reducing valve 36 Main spool 37 Pilot piston 37L, 37R Oil chamber 38 Main relief valve 39 Unload valve 40 Position detector 41 Proportional solenoid 42L, 42R Solenoid 50 Acceleration cylinder 51 Proportional solenoid 52 Main spool 53 Position detector

Claims (2)

A hydraulic pump driven by a vehicle engine, a plurality of actuators using the hydraulic pump as a hydraulic source, an accelerator cylinder for operating the plurality of actuators at a desired speed, and operating each of the plurality of actuators And a control valve having a plurality of switching valves for supplying and discharging pressure oil for use, and the accelerator cylinder is used in a work machine having a position detector that detects a position according to the operation amount, A control device having a controller for controlling the control valve,
The controller includes pressure oil supply state determining means for determining whether or not pressure oil is supplied to the control valve, and the pressure oil supply state determining means temporarily operates only the accelerator cylinder, A control device for a work machine that determines whether pressure oil is supplied to the control valve based on a signal from the position detector of the accelerator cylinder. Each of the plurality of switching valves has a position detector that detects a position according to the operation amount,
The controller includes valve abnormality detection means for detecting whether or not the control valve is abnormal, and the valve abnormality detection means determines that pressure oil has been supplied to the control valve by the pressure oil supply state determination means. 2. The work machine control device according to claim 1, further comprising detecting whether or not the control valve is abnormal based on signals from position detectors included in the plurality of switching valves.

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