Abstract:
A maintenance device for a construction machine includes: an abnormality detection means for detecting abnormality of an apparatus installed on the construction machine; an abnormality information output means for outputting abnormality information about the apparatus detected by the abnormality detection means; and a maintenance mode setting means for setting a maintenance mode for performing a maintenance work of the apparatus, wherein the abnormality information output means for eliminating negation or output of the information, if any abnormality of the apparatus is detected in a state in which the maintenance mode is set by the maintenance mode setting means.

Description:
TECHNICAL FIELD 
     The present invention relates to a construction machine such as a hydraulic excavator, in particular to a maintenance device for a construction machine that disables output of abnormality information during maintenance work. 
     BACKGROUND ART 
     Commonly, a construction machine such as a hydraulic excavator has a controller (information processing device) installed on it that electronically controls the operation of various in-vehicle devices and apparatuses. The controller has a failure determination function to determine whether the various in-vehicle devices and apparatuses operate normally inside the construction machine. A result of the failure determination by the failure determination function is temporarily stored at the controller and then periodically transmitted to an information center or the like via a wireless communication terminal for a subsequent use, for instance, for the analysis of the cause of failure of the vehicle body. 
     The failure determination function of the controller is always working. This may cause the controller to determine that a failure has occurred in the absence of abnormalities (or malfunctions) in the in-vehicle device or apparatus as in the case of maintenance work of the vehicle body, such as exchange of parts, and to transmit abnormality information. However, the information center that received this abnormality information is unable to accurately determine whether the abnormality information is correct, i.e., whether it is caused by a failure or by a maintenance work, which makes it difficult to obtain correct data. 
     To avoid this, for instance, PTL 1 indicated below proposes a technology that eliminates transmission and reception of abnormality information generated upon exchange of parts by preliminarily setting, for instance, position information about a service shop where a maintenance work is performed or its periphery and road information. PTL 2 indicated below proposes a technology that eliminates transmission of abnormality information when an abnormality diagnosis apparatus that is able to collect abnormality information is connected to the vehicle body, for instance, at a service shop. 
     CITATION LIST 
     Patent Literature 
     PTL1: JP 2011-5880 A 
     PTL2: JP 2005-41438 A 
     SUMMARY OF INVENTION 
     Technical Problem 
     However, the above-mentioned technologies require that position information about the service shop where maintenance work is performed or its periphery and road information is set in advance and in addition, abnormality information about maintenance work performed at a place other than the service shop such as a customer site is difficult to be accurately determined whether it is correct. In case that failure diagnosis equipment is used, the equipment must be connected to the vehicle body all the time during the maintenance operation. 
     The present invention is to solve these problems and has for its main object to provide a novel maintenance device for a construction machine that is able to eliminate output of erroneous abnormality information that is generated upon a maintenance work. 
     Solution to Problem 
     In order to solve the problem, a maintenance device for a construction machine according to the 1st invention comprises: an abnormality detection means for detecting abnormality of an apparatus installed on the construction machine; an abnormality information output means for outputting abnormality information about the apparatus detected by the abnormality detection means; and a maintenance mode setting means for setting a maintenance mode for performing a maintenance work of the apparatus, wherein the abnormality information output means for eliminating negation or output of the information, if any abnormality of the apparatus is detected in a state in which the maintenance mode is set by the maintenance mode setting means. 
     This arrangement reliably avoids output erroneous abnormality information that is generated upon maintenance work by switching over the mode of the construction machine to a maintenance mode prior to upon maintenance work. This eliminates reception of erroneous abnormality information and in addition contributes to a reduction in communication load. The term “maintenance mode” as used herein refers to a state or condition in which although various devices and apparatuses installed on the construction machine as exemplified later are in an activated state or condition by being supplied energy, for instance, from batteries through keying on of the engine switch in order to maintain them, but in principle the engine is stopped. 
     According to the 2nd invention, in the maintenance device for a construction machine according to the 1st invention, the maintenance mode setting means, upon receipt of a request for setting a maintenance mode, requests inputting a password for authentication and allows the maintenance mode to be set if the password is identical with a preset password. This arrangement allows only regular personnel who participate in the maintenance work who know the relevant password to set the construction machine in a maintenance mode and thus enables output and notice of abnormality information if exchange or modification of the apparatus by a person other than the regular personnel who participate in the maintenance work occurs. 
     According to the 3rd invention, the maintenance device for a construction machine according to the 1st and the 2nd inventions further comprises: an engine start up lock means for locking start up of an engine in a state in which the maintenance mode is set, wherein the engine start up lock means, if a request for engine start up is made in a state in which the maintenance mode is set, requests inputting a password for authentication and if the input password is identical with a preset password, unlocks the engine start up. 
     This arrangement enables the engine to be directly started up in the maintenance mode. Consequently, upon maintenance work with starting up the engine, such as test drive, if any abnormality is detected in various in-vehicle devices and apparatuses, a state in which negating or outputting such information is eliminated can be maintained. 
     According to the 4th invention, the maintenance device for a construction machine according to any one of the 1st through the 3rd invention further comprises: a maintenance mode notice means for indicating that the construction machine is in a maintenance mode. This arrangement enables the operator to recognize without fail that the maintenance mode is set via display on the monitor screen or sound. 
     According to the 5th invention, in the maintenance device for a construction machine according to any one of the 1st through the 4th invention, the maintenance mode setting means, the engine start up lock means, and the maintenance mode notice means constitute a monitor device that includes an input means having a maintenance mode switch and a display means. This arrangement enables the operator to use a single monitor device to perform, for instance, on/off of the maintenance mode switch and input of the password as well as display of the abnormality information. 
     Advantageous Effects of Invention 
     According to the present invention, the construction machine is provided with a maintenance mode setting means that upon a maintenance work causes the construction machine to be switched to a maintenance mode prior to the maintenance work. This prevents the abnormality detection means from outputting erroneous abnormality information that is generated upon maintenance work. This eliminates transmission and reception of erroneous abnormality information, so that communication data amount can be decreased, which contributes to a decrease in communication load. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a perspective view showing an embodiment of a hydraulic excavator  100 , one of the construction machines according to the present invention; 
         FIG. 2  is an overall view showing a hydraulic system  200  controlled by a controller  30 ; 
         FIG. 3  is a block diagram showing the arrangement of a maintenance device  300  of the present invention; 
         FIG. 4  is a front view showing an example of a monitor device  25 ; 
         FIG. 5  is a flowchart illustrating the flow of processing of abnormality information by the maintenance device  300  of the present invention; 
         FIG. 6  is a state transition diagram of the vehicle body in case a maintenance mode is set; 
         FIG. 7  is a state transition diagram of the vehicle body in case a maintenance mode is set; 
         FIG. 8  is a front view of a display example of a monitor device  25  in case input of a password is requested; 
         FIG. 9  is flowchart illustrating the flow of processing in case input of an authentication password is requested upon transition to a maintenance mode; and 
         FIG. 10  is a flowchart illustrating the flow of processing in case the engine is directly started up. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     Now, an embodiment of the present invention is explained with reference to the attached drawings.  FIG. 1  shows an embodiment of a hydraulic excavator  100 , which is one of the construction machines according to the present invention. As shown in  FIG. 1 , the hydraulic excavator  100  includes as main components an undercarriage  10  that travels with a crawler and an upperstructure  20  provided swingably on the undercarriage  10 . The upperstructure  20  includes a cab  21  having a driver seat  21   a  and a front operation machine  22  on the front side of an upperstructure frame (not shown) and on the back side an engine room  23  accommodating an engine, a heat exchanger (not shown) and so on and on the further back side of these a weight  24 , etc. 
     The front operation machine  22  includes a boom  22   a , an arm  22   b , bucket  22   c  and hydraulic cylinders  46 ,  46  . . . and so on. These parts are operated by operating operation levers  21   b  provided on both sides of the driver seat  21   a  in the cab  21  to slide the respective hydraulic cylinders  46 ,  46 , . . . . In the configuration shown in  FIG. 1 , the bucket  22   c  is attached to a leading end of the arm  22   b . However, instead of the bucket  22   c , various attachments such as a grabbler may be attached. The movement mechanism of the undercarriage  10  may use tires instead of the crawler. 
     In front of the driver seat  21   a  is provided a monitor device  25  provided with a liquid crystal display unit, which is able to display various types of information described later. Near the operation lever  21   b  on the left side of the driver seat  21   a  is provided a gate lock lever (GL)  21   c . When the gate lock lever  21   c  is held up, a locked state is set. In this state, if the operation lever  21   b  is tilted while the engine is being started up, the vehicle body will not move and tilting down of the gate lock lever  21   c  allows the vehicle body to move. 
     At the back of the driver seat  21   a , for instance, a controller  30  and a wireless communication terminal  31  are accommodated. The controller  30  controls overall the hydraulic system  200  as shown in  FIG. 2 . In  FIG. 2 , reference numeral  40  denotes an engine having an output axle  41 , to which are connected a first hydraulic pump  42 , a second hydraulic pump  43 , and a third hydraulic pump  44 , which are variable displacement pumps. Pressure oil delivered from each of the hydraulic pumps  42 ,  43 ,  44  is sent to a hydraulic circuit  45  that includes a control valve and is controlled for its quantity and flow direction and supplied to, for instance, a hydraulic cylinder  46  and a hydraulic motor  47 . 
     The controller  30  receives signals that are input from an engine control dial  50 , various types of sensors  51 , and the operation lever  21   b  and so on and integrally controls an engine control computing unit  30   a  and a pump control computing unit  30   b  based on the input signals. 
     That is, the engine control dial  50  is able to adjust a command value of rotation speed. The command rotation speed adjusted by the engine control dial  50  is input to the engine control computing unit  30   a . The engine control computing unit  30   a  calculates a target engine rotation speed based on the value input to it and sends the calculated target engine rotation speed to an engine control unit (ECU)  48 . The ECU  48  controls the rotation speed of the engine based on the target engine rotation speed. 
     On the other hand, a signal from the sensor  51  that detects pump pressure, etc. and an operation signal from the operation lever  21   b  are input into the engine control computing unit  30   a  and the pump control computing unit  30   b . The pump control computing unit  30   b  calculates command values based on the input values and controls the hydraulic pumps  42 ,  43 ,  44  to be driven based on the calculated command values. Specifically, the pump control computing unit  30   b  is configured to send pump torque pressure necessary for pump regulators  42   a ,  43   a ,  44   a  that regulate pump deliveries so that pumping rates in correspondence to the operation amount of the operation lever  21   b  can be obtained. 
       FIG. 3  is a block diagram showing the arrangement of a maintenance device  300  according to the present invention, focusing on the controller  30 . As shown in  FIG. 3 , the maintenance device  300  includes the controller  30 , an information controller  60 , and a wireless communication terminal  61  and so on. The controller  30  is constituted by an information processing device including hardware such as input/output interfaces  31 ,  32 , a CPU  33 , a ROM  34 , and a RAM  35 . 
     To the input/output interface  31  of the controller  30  are input elements S such as a sensor signal S 1  and an engine key switch signal S 2  and predetermined computing processing is performed at the CPU  33  based on the input elements S. The calculated output signal as command signals are output from the input/output interface  32  to hydraulic pumps  42  to  44  and actuator  36  such as a hydraulic cylinder  46 . A control program used to cause predetermined computing processing to be executed at the CPU  33  is stored at the ROM  34 . It is loaded at the RAM  35  when the engine key switch signal S 2  is input and sequentially executes various controls described later. 
     The controller  30  has an abnormality detection function (abnormality detection program) that detects abnormality of various devices and apparatuses installed on the vehicle based on signals input from them. If the controller  30  determines that abnormality is detected, it causes it to be brought on display on the monitor device  25  in front of the driver seat  21   a .  FIG. 4  shows an example of the monitor device  25 . The monitor  25  has a monitor body  25   a  in a rectangular shape and a liquid crystal display unit  25   b  on the front surface of the monitor body  25   a  and an input unit  25   c  constituted by a plurality of input switches on the lower part of the monitor body  25 . 
     Among the plurality of input switches F 1  to F 7  that constitute the input unit  25   c  is provided a maintenance mode switch F 6  for switching the mode of the vehicle body to a maintenance mode. When, for instance, a maintenance person presses the maintenance mode switch F 6  (switches on) after turning the engine key switch on, the vehicle body is switched over to a maintenance mode as described later, and the switch over of the vehicle body to a maintenance mode is brought up on display, for instance by lighting up an icon  25   d  at the liquid crystal display unit  25   b . The switch over signal to switch to the maintenance mode is input into the controller  30  and the controller  30  switches over the mode of the vehicle body to a maintenance mode. 
     The operator can visually grasp what abnormality occurs to the vehicle body on the driver seat  21   a  by acknowledging the abnormality information that is brought up on display at the monitor device  25 . The controller  30  is configured to perform not only processing for bringing up an alarm on display at the monitor device  25  but also processing for issuing audible alarm if the abnormality is serious, for instance, by activating a buzzer device  26  to issue a warning buzzer sound to notify the operator and the like of occurrence of an emergency without fail. 
     This abnormality information is simultaneously stored at the information controller  60 , which transmits the stored abnormality information as needed or periodically to a server  70  via the wireless communication device  61 . The server  70  in receipt of this signal stores the received abnormality information at an abnormality information database  71 . This allows a terminal  72  at each business site or factory to confirm the abnormality information by accessing to the server  70 . 
       FIG. 5  is a flowchart illustrating the flow of processing of abnormality information by the maintenance device  300  according to the present invention having the configuration as described above. As shown in  FIG. 5 , the maintenance device  300  determines in a first step S 100  whether abnormality is detected based on input signals from input elements S such as various sensors. If it determines that abnormality is detected (YES), the operation proceeds to a next step S 102 . Detection of the abnormality is achieved as follows. If, for instance, disconnection or short occurs between sensor signals, then the voltage value of a sensor signal that is input into the controller  30  exceeds a certain threshold value. Consequently, the controller  30  detects sensor high voltage abnormality if the voltage value of the sensor signal exceeds the upper threshold value. On the contrary, if the voltage value of the sensor signal is below the lower threshold value, the controller  30  detects sensor low voltage abnormality. 
     In step S 102  the controller  30  determines whether the vehicle body is in a maintenance mode upon detection of the abnormality. If it determines that the vehicle body is in a maintenance mode (YES), the information controller  60  negates the abnormality information without storing it and terminates the processing. On the other hand, if the controller  30  determines that the vehicle body is not in a maintenance mode (NO), that is, the vehicle body is in a normal work state, the operation proceeds to a next step S 104 . In step S 104 , the controller  30  causes an alarm for the abnormality to be brought up on display on the liquid crystal display unit  25   b  of the monitor device  25  and simultaneously, in step S 106 , the information controller  60  stores the abnormality information and the operation proceeds to a next step S 108 . In step S 108 , processing to transmit the stored abnormality information from the wireless communication device  61  to the server  70  is executed after a predetermined time elapsed. 
     As described above, the maintenance device according to the present invention, which includes the maintenance mode switch  25   c  that switches over the vehicle body to a maintenance mode, for instance, at the monitor device  25 , is able to reliably avoid outputting erroneous abnormality information that would arise with the maintenance work by switching the vehicle body to a maintenance mode with the switch  25   c  before a maintenance work, such as exchange of a part or parts, is started. This eliminates transmission and reception of erroneous abnormality information so that the amount of communication data can be reduced, which contributes to a reduction in communication load. The switching operation may be achieved by using a touch panel or dial operation instead of the maintenance mode switch  25   c.    
       FIGS. 6 and 7  show each the transition state of the vehicle body when the maintenance mode as described above is set. First, when the vehicle body is in a stop state S 1 , the engine key switch is off and the engine is in a stop state as shown in  FIG. 6 . If the engine key switch is turned to key on in this state, the power-supply line from the batteries is connected to the controller  30  and other parts to activate the controller  30  to transition to a preparation state S 2  for awaiting the start up of the engine. 
     If, in this preparation state, the engine key switch is further turned to a start position, the engine starts up and the vehicle body transitions to a standby state S 4 . In this state, the gate lock lever  21   b  is in a locked state. When the gate lock lever  21   b  is unlocked, the vehicle body transitions to a work state S 5  to be ready for the operation of the front work machine  22  or travel operation of the undercarriage  10 . If, in the work state S 5 , the engine key switch is returned to the original position to key off, the engine is stopped to bring the vehicle body to a stop state. 
     On the other hand, if the maintenance mode switch F 6  of the monitor device  25  is pressed in the preparation state S 2 , the vehicle body transitions to a maintenance state (maintenance mode) S 3 . In this case, the controller  30  may be configured to request inputting an authentication password and allow the vehicle body to transition to the maintenance state S 3  only if the authentication password is identical to a preset one.  FIG. 8  shows an example of display at the monitor device  25  when the inputting a password is requested. In case the password for authentication is requested, it should be of, for instance, 8 digits and a message such as “INPUT A PASSWORD” is brought up on display at the display unit  25   a  as shown in  FIG. 8 . 
     By requesting an authentication password upon transition to a maintenance mode and allowing transition to a maintenance state (maintenance mode) S 3  only when the authentication password is identical to the preset one as described, it is possible to allow the maintenance work to be dealt with only by a qualified person or persons. To start up the engine in the maintenance state S 3 , the engine key switch is once turned off to return to the stop state S 1  and then turned to the preparation state S 2 . Thereafter, the engine key switch is further turned to start up the engine. Thus, the vehicle body transitions to the standby state S 4 . 
       FIG. 9  is a flowchart illustrating the flow of processing in case input of an authentication password is requested upon transition to the maintenance mode. First, the controller  30  determines whether the maintenance mode switch F 6  is pressed in the first step S 200 . If it determines that the maintenance mode switch F 6  is not pressed (NO), it causes the processing to end immediately, whereas if it determines that the maintenance mode switch F 6  is pressed (YES), it causes the operation to proceed to the next step S 202 . In step S 202 , the controller determines whether the engine is started up. If it determines that the engine is started up (YES), it causes the processing to end immediately, whereas if it determines that the engine is not started up, that is, the engine is at a stop (NO), it causes the operation to proceed to the next step S 204  to execute the processing for requesting inputting an authentication password and then to the next step S 206 . 
     In step S 206 , the controller  30  makes a decision on the input password. If it decides that the password is identical (YES), it causes the operation to proceed to the next step S 208  to allow the vehicle body to transition to the maintenance state, whereas if it decides that the input password is not identical (NO), it causes the operation to proceed to step S 210  to buzz an alarm to perform processing for notifying the occurrence of an input mistake. Then it causes the operation to proceed to the next step S 212 . The controller  30  may be configured to cause the monitor device  25  to bring up on display a predetermined warning instead of or in addition to the buzzer warning. The controller  30  may be configured to set a limit to the number of times of inputting any password to allow reentering any password until the set number of times of inputting is reached and disallow further reentering any password once the number of times of inputting of passwords exceeds the set number of times. 
     In step S 212 , the controller  30  executes the processing to bring the vehicle body to an engine key switch off waiting state and then causes the operation to proceed to the next step S 214  to determine whether the engine key switch is turned off. If it determines that the engine key switch is not turned off (NO), it causes the operation to return to step S 212 , whereas if it determines that the engine key switch is turned on (YES), it causes the operation to proceed to the next step S 216  to cause the vehicle body to transition to the stop state and causes the processing to end. 
     Here, as shown in  FIG. 7 , the controller  30  may be configured to request inputting an authentication password in case the engine is started up in the maintenance state S 3  to allow the vehicle body to transition to the standby state S 4 . In other words, if a person other than the authorized people who participate in the maintenance work accidentally starts up the engine in the maintenance state S 3 , unforeseen circumstances may arise. Accordingly, the controller  30  is configured to request inputting an authentication password in case the engine is to be started up directly in the maintenance state S 3  and allow the engine to be started up only if the input password is identical with the preset one. This enables unforeseen circumstances such as start up of the engine during maintenance work to be avoided. 
     If it is necessary to perform this maintenance work in a state in which the engine is started up, the controller  30  may be configured to enable transition from the maintenance state S 3  to the standby state S 4  directly to allow the maintenance mode to continue. This avoids inconveniences such as storage and transmission of abnormality information associated with the maintenance work at the time when the engine is started up. In this case, the controller  30  is configured to cause the maintenance state  33  to be reset when the engine key switch is turned off (or the engine is in a stop state). 
       FIG. 10  is a flowchart illustrating the flow of processing when the engine is directly started up in the maintenance state S 3  as described above. First, the controller  30  determines in a first step S 300  whether the vehicle body is at present in the maintenance state S 3 . If it determines that the vehicle body is not in the maintenance state S 3  (NO), it causes the processing to end, whereas if it determines that the vehicle body is in the maintenance state S 3  (YES), it causes the operation to proceed to the next step S 302 . In step S 302 , the controller  30  determines whether the engine key switch is turned to the engine start up position. If it determines that the engine key switch is not turned to that position (NO), it causes the processing to end directly, whereas if it determines that the engine key switch is turned to that position (YES), it causes the operation to proceed to the next step S 304  to request an authentication password and then to the next step S 306 . 
     In step S 306 , the controller  30  makes a decision as to whether the input password is identical with the preset one. If it decides that the input password is not identical with the preset one, it causes the processing to end directly, whereas if it decides that the input password is identical with the preset one (YES), it causes the operation to proceed to the next step S 308  to transition to the standby state S 4  and causes the processing to end. 
     It often happens that during maintenance work, another worker who is unaware that the vehicle body is being maintained tries to drive it. To avoid this, when the engine is to be started up, a warning signal for driving the vehicle body, such as a horn sound, is given according to a standard operating procedure. However, some operators may disregard or forget such a standard operating procedure. Accordingly, the configuration to request an authentication password upon starting up the engine during the maintenance work as described above eliminates a risk that the vehicle body is operated by a person other than the person who participates in the maintenance work and secures safety upon the maintenance work. In this embodiment, explanation is made on the example in which a hydraulic excavator is used as the construction machine. However, the same is equally true of wheel loaders, dump trucks, and bulldozers and so on. 
     REFERENCE SIGNS LIST 
     
         
           100  . . . hydraulic excavator (construction machine) 
           200  . . . hydraulic system 
           300  . . . maintenance device 
           10  . . . undercarriage 
           20  . . . upperstructure 
           25  . . . monitor device (maintenance mode setting means, engine start lock means, maintenance mode notice means) 
           25   b  . . . display unit 
           25   c  . . . input unit 
           26  . . . buzzer device (maintenance mode notice means) 
           30  . . . controller (abnormality detection means, maintenance mode setting means, engine start up lock means) 
           60  . . . information controller (abnormality information output means) 
           61  . . . wireless communication terminal (abnormality information output means) 
         F 6  . . . maintenance mode switch