Patent Publication Number: US-7904225-B2

Title: Working machine

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims priority to Japanese Patent Application No. 2005-163681 filed on Jun. 3, 2005. The entire disclosure of Japanese Patent Application No. 2005-163681 is hereby incorporated herein by reference. 
     TECHNICAL FIELD 
     The present invention relates to a working machine that includes working equipment such as a hydraulic breaker and a hydraulic compactor that is operated by a vibration generating device that is supplied with pressure oil from a hydraulic pump and generates vibration. 
     BACKGROUND ART 
     Known examples of this type of working machine are provided by hydraulic working machines disclosed in Japanese Patent Laid-Open Publication No. 7-331707 and Japanese Patent Laid-Open Publication No. 11-100869. In the aforementioned hydraulic working machine according to Japanese Patent Laid-Open Publication No. 7-331707, if a breaker is operated in the state where a breaker mode is selected by a mode change switch, flow rate control is performed so that a hydraulic pump is brought in a constant low capacity state. Also, in the aforementioned hydraulic working machine according to Japanese Patent Laid-Open Publication No. 11-100869, if a breaker is operated by an operation pedal in the state where a breaker mode is selected by the mode change switch, the smallest discharging amount is selected from a discharging amount that is set by a maximum discharging amount setting section, a discharging amount that is subjected to positive control in accordance with the operation amount of the operation pedal, and a discharging amount that is subjected to P-Q control that limits the discharging amount so that the hydraulic pump may not be brought in an overload state. Thus, flow rate control is performed so that the discharging amount of the hydraulic pump is set to the selected discharging amount. 
     DISCLOSURE OF INVENTION 
     However, since, even in the cases of the aforementioned known working machines, the above-discussed flow rate control is not performed in the case where modes other than the breaker mode are selected by the mode change switch when the breaker is operated, the flow rate of the pressure oil that is supplied to the breaker may be excessive in some modes. This may cause damage to a machine body, hydraulic equipment, or the like. 
     If a working machine can be configured to surely determine whether a breaker is in an operation state, action can be taken to protect a machine body and the like. Therefore, it is possible to prevent damage to the machine body and the like. In addition to this, the degree of damage to the machine body and the like can be determined. Therefore, it is possible to optimize the timing of maintenance and the like. 
     The present invention is aimed at solving the these situations, and its object is to provide a working machine that can surely determine whether working equipment such as a hydraulic breaker is in an operation state. 
     To achieve the above object, a working machine control device according to the first aspect of the present invention is adapted to control a working machine with working equipment that is operated by a vibration generating device that is supplied with pressure oil from a hydraulic pump and generates vibration. The working machine control device includes a pressure sensing section and a controller. The pressure sensing section is configured and arranged to detect the pump pressure of said hydraulic pump. The controller is configured to obtain the frequency characteristic of the pump pressure based on a pump pressure value that is detected by the pressure sensing section, and to determine whether said working equipment is in an operation state or not based on the frequency characteristic. 
     The working machine control device according to the second aspect of the present invention includes an alarm issuing section that is configured and arranged to issue an alarm, and said controller is configured to selectively control the working machine in at least one of a prescribed control mode for working by using said working equipment, and a different control mode different from the prescribed control mode. In this configuration, said controller is further configured to send a control signal to said alarm issuing section to issue the alarm when the controller determines that said working equipment is in the operation state while said different control mode is executed. 
     The working machine control device according to the third aspect of the present invention includes a flow rate adjustment section configured and arranged to adjust the flow rate of the pressure oil that is supplied from said hydraulic pump to said working equipment, and said controller is configured to selectively control the working machine in at least one of a prescribed control mode for working by using said working equipment, and a different control mode different from the prescribed control mode. In this configuration, said controller is further configured to send a command signal to said flow rate adjustment section to limit the flow rate of the pressure oil that is supplied from said hydraulic pump to said working equipment when the controller determines that said working equipment is in the operation state while said different control mode is executed. 
     In the working machine control device according to the fourth aspect of the present invention, said controller is configured to selectively control the working machine in a prescribed control mode that for working by using said working equipment, and a different control mode different from the prescribed control mode. In this configuration, said controller is further configured to switch from said different control mode to the prescribed control mode as a control mode to be executed when the controller determines that said working equipment is in the operation state while said different control mode is executed. 
     In the working machine control device according to the fifth aspect of the present invention, when the controller determines that said working equipment is in the operation state, said controller is configured to measure the amount of operation time in which said working equipment is in the operation state and to store the accumulated amount of the operation time. 
     In the working machine control device according to the sixth aspect of the present invention, said controller is configured to determine whether said working equipment is in the operation state or not based on said frequency characteristic, and an amplitude center value and an amplitude value of the waveform of the pump pressure. 
     In the working machine control device according to the seventh aspect of the present invention, said controller is further configured to determine the type of said working equipment based on said frequency characteristic. 
     In the working machine control device according to the eighth aspect the present invention, said controller is further configured to determine the type of said working equipment based on said frequency characteristic, and the amplitude center value and the amplitude value of the waveform of the pump pressure. 
     A working machine in accordance with the present invention preferably includes the working machine control device according to any of the above aspects of the present invention. 
     According to the present invention, since the working machine includes the controller that obtains the frequency characteristic of the pump pressure based on the pump pressure value that is detected by the pressure sensing section and determines whether the working equipment is in an operation state or not based on the frequency characteristic, it is possible to surely determine whether the working equipment is in an operation state or not. For this reason, if the controller determines that the working equipment is in the operation state in the state where the different control mode different from the prescribed control mode that suits for working by using the working equipment such as a hydraulic breaker, the alarm issuing section issues an alarm. Therefore, it is possible to urge an operator to switch to the prescribed control mode, and thus to prevent damage to a machine body, hydraulic equipment, and the like. 
     Also, since, if determining that the working equipment is in the operation state in the state where the different control mode different from the prescribed control mode, the flow rate adjustment section limits the flow rate of the pressure oil that is supplied from the hydraulic pump to the working equipment, it is possible to prevent damage to a machine body, hydraulic equipment, and the like. 
     Also, since, if determining that the working equipment is in the operation state in the state where the different control mode different from the prescribed control mode, the controller switches from the different mode to the prescribed control mode as a control mode to be executed, it is possible to prevent damage to a machine body, hydraulic equipment, and the like. 
     Also, since, if determining that the working equipment is in the operation state, the controller measures the elapsed time in which the working equipment is in the operation state and stores the accumulated operation time, it is possible to determine the damaged degree of a machine body or the like based on the accumulated operation time. Therefore, it is possible to optimize the timing of maintenance and the like. 
     Also, since it is determined whether the working equipment is in the operation state or not based on the frequency characteristic, and the amplitude center value and the amplitude value of the waveform of the pump pressure, it is possible to more surely determine whether the working equipment is in the operation state or not. 
     Also, since the type of the working equipment is determined based on the frequency characteristic, it is possible to surely determine the type of the working equipment that is mounted to the working machine. 
     Furthermore, since the type of the working equipment is determined based on the frequency characteristic, and the amplitude center value and the amplitude value of the waveform of the pump pressure, it is possible to surely determine the type of the working equipment that is mounted to the working machine. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a side view of a hydraulic shovel according to a first embodiment of the present invention. 
         FIG. 2  is a schematic structural view of a hydraulic driving system of the hydraulic shovel according to the first embodiment of the present invention. 
         FIG. 3  is an engine power torque characteristic diagram. 
         FIG. 4  includes a plurality of diagrams (a) to (c) showing exemplary pump pressure waveforms in working types. 
         FIG. 5  includes a plurality of diagrams (a) to (c) showing the results of frequency analysis of the pump pressure waveforms in working types. 
         FIG. 6  is a functional block diagram related to breaker work determination. 
         FIG. 7  is a flow chart showing the processing of a controller according to the first embodiment. 
     
    
    
     BEST MODE OF CARRYING OUT THE INVENTION 
     The following description will describe working machines equipped with working machine control devices according to exemplary embodiments of the present invention with reference to drawings. In addition, in the following embodiments, the present invention is adopted to a hydraulic shovel as a working machine. 
       FIG. 1  is a side view of a hydraulic shovel according to a first embodiment of the present invention, and shows the state where breaker work is performed. 
     The hydraulic shovel  1  according to this embodiment includes a lower travel unit  2 , and an upper revolving unit  4 , a working portion  8 , and an cab  9 . The upper revolving unit  4  is mounted to the aforementioned lower travel unit  2  via a revolving apparatus  3 . The working portion  8  is mounted to the front central part of the upper revolving unit  4 , and includes a boom  5 , an arm  6  and a breaker  7  that are pivotally coupled to each other from the upper revolving unit  4  side in this order. The cab  9  is arranged on the front left part of the upper revolving unit  4 . A boom cylinder  10 , an arm cylinder  11 , and an attachment cylinder  12  are mounted to the aforementioned working portion  8 . The boom cylinder  10  drives and pivots the boom  5 . The arm cylinder  11  drives and pivots the arm  6 . The attachment cylinder  12  drives and pivots the breaker  7 . The working portion  8  is driven to be folded or to be raised/lowered by expanding/contracting operation of the boom cylinder  10 , the arm cylinder  11 , and the attachment cylinder  12 . Note that, although the hydraulic breaker  7  is mounted as working equipment (working attachment) in the hydraulic shovel  1  shown in  FIG. 1 , the hydraulic breaker  7  can be replaced with a bucket, a hydraulic compactor, a hydraulic crusher, a hydraulic cutter or the like as an attachment for a wide variety of uses in accordance with working types. 
       FIG. 2  is a schematic structural view of a hydraulic driving system of the hydraulic shovel according to this embodiment of the present invention. 
     In the hydraulic driving system shown in  FIG. 2 , pressure oil that is discharged from a hydraulic pump  16  that is driven by an engine  15  is supplied into and exhausted from the boom cylinder  10 , the arm cylinder  11 , the attachment cylinder  12 , a travel hydraulic motor  18  that powers the lower travel unit  2 , and a revolving hydraulic motor  19  that drives the revolving apparatus  3  via a main operation valve  17 . The aforementioned main operation valve  17  is acted upon by pilot pressure oil from pressure reducing valves  22  and  23  that are attached to working portion control levers  20  and  21 , and pilot pressure oil from pressure reducing valves  26  and  27  that are attached to travel control levers  24  and  25 . The pilot pressure oil that acts upon the main operation valve  17  performs oil path switching operation of the main operation valve  17 . Thus, the operation of the working portion control levers  20  and  21 , and the travel control levers  24  and  25  performs folding or raising/lowering operation of the working portion  8 , revolving operation of the upper revolving unit  4 , and running operation of the lower travel unit  2 . Note that tanks are shown by reference numerals  28 ,  29 ,  30  and  31 , and pilot pressure oil sources are shown by reference numerals  32 ,  33 ,  34  and  35 , in  FIG. 2 . 
     Also, the pressure oil that is discharged from the aforementioned hydraulic pump  16  is supplied to the breaker  7  via an attachment operation valve  36 . This breaker  7  includes a chisel  40 , and a vibration generating device  39  that vibrates the chisel  40 , and is configured to suitably perform breaking work by means of the chisel  40  that is struck by a piston  38  in the vibration generating device  39 . The vibration generating device  39  includes a cylinder  37 , the piston  38  that is supplied with the pressure oil from the hydraulic pump  16  to vibrate within the aforementioned cylinder  37 , and a flow path switching valve  34 . The piston  38  is inserted in the cylinder  37 . The space inside the cylinder  37  is divided into a gas chamber  61 , and first and second pressure oil chambers  62  and  63 . The gas chamber  61  is filled up with gas, such as nitrogen gas. The piston  38  is pressed by the pressure of the gas in the gas chamber  61  in a direction in which the piston  38  presses the chisel  40  (i.e., downward). The pressure oil that is discharged from the hydraulic pump  16  is supplied into and exhausted from the first and second pressure oil chambers  62  and  63 . The first pressure oil chamber  62  is located under the gas chamber  61 . If the pressure oil flows into the first pressure oil chamber  62 , a force is applied to the piston  38  by the pressure of the pressure oil in the direction in which the piston  38  presses the chisel  40 . The second pressure oil chamber  63  is located under the first pressure oil chamber  62 . If the pressure oil flows into the second pressure oil chamber  63 , a force is applied to the piston  38  by the pressure of the pressure oil in a direction in which the piston  38  departs away from the chisel  40  (i.e., upward). The flow path switching valve  34  switches between the income and the outgo of the pressure oil in the first pressure oil chamber  62 , and the income and the outgo of the pressure oil in the second pressure oil chamber  63 . If the flow path switching valve  34  is brought into a first state where the flow path switching valve  34  allows the pressure oil to flow out from the first pressure oil chamber  62  and to flow into the second pressure oil chamber  63 , the piston  38  is raised by the pressure of the pressure oil that flows into the second pressure oil chamber  63 , and departs away from the chisel  40 . In this state, the gas in the gas chamber  61  is compressed by the piston  38 . If the piston  38  is raised, the flow path switching valve  34  is brought in a second state where the flow path switching valve  34  allows the pressure oil to flow out from the second pressure oil chamber  63  and to flow into the first pressure oil chamber  62 . Thus, the piston  38  is rapidly lowered by the pressure of the pressure oil in the first pressure oil chamber  62  and the pressure of the gas in the gas chamber  61  to strike the chisel. When the piston  38  strikes the chisel, the flow path switching valve  34  is brought into the first state again, and the aforementioned operation will be repeated. 
     A pilot pressure operation type switching valve  43  is interposed on a tube path  42  that connects a discharge-side port  41  of the breaker  7  and an attachment operation valve  36 . The switching valve  43  is switched from a position A to a position B, when pilot pressure oil acts upon an operation portion  43   a . When the switching valve is switched to the position B, the oil that is returned from the breaker  7  is directly drained into the tank  30 . An solenoid switching valve  44  is interposed on an oil path from the operation portion  43   a  of the switching valve  43  to the pilot pressure oil source  35 . The solenoid switching valve  44  is switched from the position A to the position B based on a command signal from the controller  45 . When the solenoid switching valve  44  is switched to the position B, the pilot pressure oil from the pilot pressure oil source  35  acts upon the operation portion  43   a  of the switching valve  43 , and thus the switching valve  43  is switched from the position A to the position B. The controller  45  preferably constitutes at least a part of the working machine control device in accordance with the illustrated embodiment. 
     The aforementioned engine  15  is a diesel type engine. An electronic governor  46  is attached to the engine  15 . The electronic governor  46  adjusts the output of the engine  15  based on the command signal from the controller  45 . 
     The aforementioned hydraulic pump  16  is a variable displacement type hydraulic pump that varies a discharge amount in accordance with the inclination angle of a swash plate  16   a . The swash plate control device  47  is attached to the hydraulic pump  16  to control the inclination angle of the swash plate  16   a  based on the command signal from the controller  45 . The discharge oil amount of the hydraulic pump  16  is controlled based on the command signal from the controller  45 . In this embodiment, the discharge pressure (pump pressure) of the hydraulic pump  16  is detected by a pressure sensor (corresponding to a “pressure sensing section” in the present invention)  48 . The detected signal is provided to the controller  45 . The controller  45  performs feedback control of the hydraulic pump  16  based on the detected signal from the pressure sensor  48 . Note that the pressure sensor  48  detects the pressure of the pressure oil at a position right after the pressure oil is discharged from the hydraulic pump  16  and before the pressure oil branches out the main operation valve  17  and the attachment operation valve  36 . 
     A pressure-reducing valve  50  is attached to the attachment operation pedal  49  that operates the aforementioned breaker  7 . The pilot pressure oil acts upon the operation portion  36   a  of the attachment operation valve  36  by depressing the attachment operation pedal  49 . A electro-hydraulic proportional flow control valve (corresponding to a “flow rate adjustment section” in the present invention)  52  is interposed on a pilot pressure oil tube path  51  from the aforementioned pressure-reducing valve  50  to the operation portion  36   a  of the attachment operation valve  36 . The valve opening degree of the electro-hydraulic proportional flow control valve  52  is adjusted based on the command signal from the controller  45 . Thus, the pilot pressure oil is supplied to the operation portion  36   a  of the attachment operation valve  36  in accordance with the valve opening degree of the electro-hydraulic proportional flow control valve  52  that is adjusted based on the command signal from the controller  45 . As a result, the adjustment of the valve opening degree of the attachment operation valve  36  controls the flow rate of the pressure oil that is supplied from the hydraulic pump  16  to the breaker  7 . In this embodiment, the pressure switch  53  detects generation of the pilot pressure in the aforementioned pilot pressure oil tube path  51 . The controller  45  is provided with an ON signal that is provided from the pressure switch  53  when the pilot pressure is generated. 
     A monitor panel  54  is disposed in the aforementioned cab  9  (see  FIG. 1 ) to serve as a setting device that allows the operator to select a desired work mode from a plurality of work modes. The monitor panel  54  includes a display portion (corresponding to an “alarm issuing section” in the present invention)  54   a  that indicates the situation of a vehicle (hydraulic shovel  1 ), alarm information and the like, and a work mode selecting switches  54   b  and  54   c  for work mode selection. In this embodiment, the work modes that can be selected by the work mode selecting switches  54   b  and  54   c  include three modes of an active mode (mode A), an economy mode (mode E), and a breaker mode (mode B) in total. Also, when the active mode is selected by the work mode select switches  54   b  and  54   c , an active mode setting command signal is provided from the monitor panel  54  to the controller  45 . When economy mode is selected by the work mode select switches  54   b  and  54   c , an economy mode setting command signal is provided from the monitor panel  54  to the controller  45 . When the breaker mode is selected by the work mode select switches  54   b  and  54   c , the breaker mode setting command signal is provided from the monitor panel  54  to the controller  45 . 
     The aforementioned controller  45  mainly includes a central processing unit (CPU) that executes a predetermined program, a read-only memory (ROM) that stores the program and various types of tables, a rewritable memory (RAM) as a working memory that is required to execute the program, an input interface (an A/D converter, a digital signal generator, etc.), and an output interface (a D/A converter, etc.). The controller  45  includes a plurality of control modes. That is, the controller  45  includes the three modes of the active mode (corresponding to a “different control mode” in the present invention), the economy mode (corresponding to the “different control mode” in the present invention), and the breaker mode (corresponding to a “prescribed control mode” in the present invention) in total. If receiving the active mode setting command signal from the aforementioned monitor panel  54 , the controller  45  sets the active mode as a control mode to be executed and performs later-discussed processing. Also, if receiving the economy mode setting command signal from the aforementioned monitor panel  54 , the controller  45  sets the economy mode as a control mode to be executed and performs later-discussed processing. Also, if receiving the breaker mode setting command signal from the aforementioned monitor panel  54 , the controller  45  sets the breaker mode as a control mode to be executed and performs later-discussed processing. Note that the aforementioned control mode may include a mode that determines control setting of the engine  15 , the hydraulic pump  16  or the like irrespective of switching operation of the work mode select switches  54   b  and  54   c  as long as the mode determines control setting of the engine  15 , the hydraulic pump  16  or the like in accordance with a work mode that is selected by the work mode select switches  54   b  and  54   c.    
     In this embodiment, the aforementioned active mode is a control mode that gives a higher priority to a working amount, and executes the following processes (A) and (B). (A) The electronic governor  46  is provided with a command signal that raises the output of the engine  15  to the rated output. (B) The swash plate control device  47  is provided with a command signal that controls the discharge flow rate of the hydraulic pump  16  so that the output torque of the engine  15  and the absorption torque of the hydraulic pump  16  match to each other at the engine power torque point shown by the symbol TP 1  in  FIG. 3  where the output of the engine  15  becomes the rated output. 
     In this embodiment, the aforementioned economy mode is a control mode that gives a higher priority to fuel efficiency, and executes the following processes (C) and (D). (C) The electronic governor  46  is provided with a command signal that sets regulation shown by the symbol L 2  in  FIG. 3  that is shifted at a predetermined rotational speed on the lower rotational speed side from a regulation line shown by the symbol L 1  in  FIG. 3  that is set as full power operation of the engine  15 . (D) The swash plate control device  47  is provided with a command signal that controls the discharge flow rate of the hydraulic pump  16  so that the output torque of the engine  15  and the absorption torque of the hydraulic pump  16  match to each other at the engine power torque point shown by the symbol TP 2  on the aforementioned regulation line L 2  in  FIG. 3  where fuel consumption is relatively small and engine output is approximately 70% of the rated output. Also, the aforementioned breaker mode is a control mode that suits the work using the breaker  7 , and executes the following processes (E) and (F) in addition to the aforementioned processes (C) and (D). (E) The electro-hydraulic proportional flow control valve  52  is provided to a command signal that restricts the flow rate of the pressure oil that is supplied from the hydraulic pump  16  to the breaker  7  to not more than an allowable flow rate of the breaker  7 . (F) The operation portion  44   a  is provided with a command signal that switches the solenoid switching valve  44  to the position B. Note that although, in this embodiment, it is a total of three kinds, the active mode, the economy mode, and the breaker mode are included as the control modes that are set by the controller  45 , a control mode other than these modes can be set in accordance with the type of work. 
       FIG. 4  includes a plurality of diagrams (a) to (c) showing exemplary pump pressure waveforms in working types. The diagram (a) of  FIG. 4  shows a pump pressure waveform in breaker work. The diagram (b) of  FIG. 4  shows a pump pressure waveform in skeleton work. The diagram (c) of  FIG. 4  shows a pump pressure waveform in dump truck loading work. Note that, in the diagrams (a) to (c) of  FIG. 4 , the vertical axes have the same scale, but the horizontal axes have different scales for the sake of clarity. Also,  FIG. 5  includes a plurality of diagrams showing the frequency characteristics that are obtained by the frequency analysis of pump pressure waveforms in working types. The diagram (a) of  FIG. 5  shows the frequency analysis of the pump pressure waveform in breaker work. The diagram (b) of  FIG. 5  shows the frequency analysis of the pump pressure waveform in skeleton work. The diagram (c) of  FIG. 5  shows the frequency analysis of the pump pressure waveform in dump truck loading work. 
     The amplitude center value of the pump pressure waveform in breaker work shown in the diagram (a) of  FIG. 4  is P 10 , and its amplitude is A 10 . In contrast to this, the amplitude center value of the pump pressure waveform in skeleton work shown in the diagram (b) of  FIG. 4  is approximately 0.8 times the value of P 10 , and its amplitude is approximately thirteen times the value of A 10 . Also, the amplitude center value of the pump pressure waveform in dump truck loading work shown in the diagram (b) of  FIG. 4  is approximately 0.85 times the value of P 10 , and its amplitude is approximately seventeen times the value of A 10 . Accordingly, the aforementioned amplitude center value P 10  and the amplitude A 10  can be used as exemplary reference values for determination whether the breaker  7  is in the operation state or not. The controller  45  stores in advance a prescribed range of P 10 ×0.9 to P 10 ×1.1 that is slightly broadened from the amplitude center value P 10 , and a prescribed range of A 10 ×0.9 to A 10 ×1.1 that is slightly broadened from the amplitude A 10 . The prescribed ranges are used as exemplary criteria for determination whether the breaker  7  is in the operation state or not. 
     Also, the frequency characteristics shown in the diagrams (a) to (c) of  FIG. 5  are different from each other in types of work. The frequency characteristics can be used as exemplary reference values for determination whether the breaker  7  is in the operation state or not. More specifically, a prescribed frequency characteristic for a prescribed type of work is preferably set in advance based on the frequency analysis results obtained by experimentally performing different types of work (e.g., breaker work, skeleton work, damp truck loading work, etc.) as well as by experimentally operating different working equipments of the same kind (e.g., breakers having the same specification manufactured by different manufacturers). For example, it is found in experiments that, when the breaker  7  is in the operation state, a particular frequency characteristic is obtained in which the frequency component (e.g., f 3  (Hz), f 4  (Hz) and f 5  (Hz)), which is not less than twice the power-spectrum average value E 2  and is not less than a prescribed threshold value E 1  in absolute value, is included in the prescribed frequency range (e.g., the frequency range from f 2  (Hz) to f 9  (Hz)) as shown in the diagram (a) of  FIG. 5 . Accordingly, in this embodiment, if the result of the frequency analysis of the pressure variation of the pump pressure shows that a frequency component, which is not less than twice the power-spectrum average value E 2  and is not less than the prescribed threshold value E 1  in absolute value, is included in the prescribed frequency range (e.g., from f 2  (Hz) to f 9  (Hz)), it can be determined that the breaker  7  is in the operation state. Note that the controller  45  stores in advance this determination logic. 
       FIG. 6  is a functional block diagram related to the breaker work determination. Also, Table 1 shows exemplary processes of various types of sections and component devices in the block diagram of  FIG. 6 . 
     
       
         
           
               
               
               
               
             
               
                 TABLE 1 
               
               
                   
               
               
                 Num. 
                 Section 
                 Processing 
                 Component Device 
               
               
                   
               
             
            
               
                 71 
                 Pump pressure signal 
                 Obtainment of pressure 
                 Pressure sensor 48, 
               
               
                   
                 input section 
                 waveform signal of pump 
                 a/d converter 
               
               
                 72 
                 Pressure switch signal 
                 Obtainment of state of pressure 
                 Pressure switch 53, 
               
               
                   
                 input section 
                 switch 
                 digital signal 
               
               
                   
                   
                   
                 generator 
               
               
                 73 
                 Signal-processing 
                 Primary processing (primary 
                 CPU 
               
               
                   
                 section 
                 delay filtering) on pump pressure 
               
               
                   
                   
                 waveform 
               
               
                 74 
                 Pump pressure data 
                 Creation of FFT (fast Fourier 
                 Memory 
               
               
                   
                 storing section 
                 transform) analysis data 
               
               
                 75 
                 Pump pressure wave 
                 Execution of FFT analysis 
                 CPU 
               
               
                   
                 analysis section 
               
               
                 76 
                 Breaker operation state 
                 Determination whether breaker 
                 CPU 
               
               
                   
                 determining section 
                 is in operation state based on 
               
               
                   
                   
                 FFT analysis result, etc. 
               
               
                 77 
                 Breaker operation time 
                 Measurement of breaker 
                 CPU 
               
               
                   
                 measuring section 
                 operation time 
               
               
                 78 
                 Breaker operation time 
                 Storage of breaker operation 
                 Memory 
               
               
                   
                 storing section 
                 time 
               
               
                 79 
                 Breaker operation time 
                 Indication of breaker operation 
                 External display 
               
               
                   
                 indicating section 
                 time 
                 (display portion 54a, 
               
               
                   
                   
                   
                 PC monitor, etc.) 
               
               
                 80 
                 Control mode input 
                 Input of control mode (mode A, B, 
                 Switch (monitor 
               
               
                   
                 section 
                 C, etc.) 
                 panel 54) 
               
               
                 81 
                 Supply flow rate setting 
                 Input flow rate setting value of 
                 Switch (monitor 
               
               
                   
                 value input section 
                 pressure oil to be supplied to 
                 panel 54) 
               
               
                   
                   
                 breaker 
               
               
                 82 
                 Control mode 
                 Comparison of control mode, and 
                 CPU 
               
               
                   
                 comparing section 
                 determination whether alarm 
               
               
                   
                   
                 command signal is provided 
               
               
                 83 
                 Control mode storing 
                 Storage of current control mode 
                 Memory 
               
               
                   
                 section 
               
               
                 84 
                 Control mode 
                 Determination of control mode 
                 CPU 
               
               
                   
                 determining section 
               
               
                 85 
                 Supply flow rate 
                 Determination of flow rate of 
                 CPU 
               
               
                   
                 determining section 
                 pressure oil to be supplied to 
               
               
                   
                   
                 breaker 
               
               
                 86 
                 Supply flow rate setting 
                 Storage of current flow rate 
                 Memory 
               
               
                   
                 value storing section 
                 setting value of pressure oil to be 
               
               
                   
                   
                 supplied to breaker 
               
               
                 87 
                 Alarm indicating 
                 Indication of alarm 
                 Display Portion 54a 
               
               
                   
                 section 
               
               
                 88 
                 Engine pump control 
                 Control of engine and oil 
                 CPU, D/A converter, 
               
               
                   
                 section 
                 pressure pump in accordance 
                 electronic governor 
               
               
                   
                   
                 with control mode 
                 46, swash plate 
               
               
                   
                   
                   
                 control device 47 
               
               
                 89 
                 Supply flow rate control 
                 Control of flow rate of pressure 
                 CPU, D/A converter, 
               
               
                   
                 section 
                 oil to be supplied to breaker 
                 electro-hydraulic 
               
               
                   
                   
                   
                 proportional flow 
               
               
                   
                   
                   
                 control valve 52 
               
               
                   
               
            
           
         
       
     
     In the block diagram shown in  FIG. 6 , the pressure waveform signal of the hydraulic pump  16  that is obtained by a pump pressure signal input section  71  is subjected to primary delay filtering in a signal-processing section  73 , and is then sent to a pump pressure data storing section  74 . The pump pressure data storing section  74  creates and stores pump pressure data based on the necessary sampling data that is obtained at a predetermined sampling period from the aforementioned pressure waveform signal that is subjected to the signal processing. The pump pressure data is provided to a pump pressure wave analysis section  75  and a breaker operation state determining section  76 . 
     The aforementioned pump pressure power wave analysis section  75  performs Fourier transform (Fast Fourier Transform) on the pump pressure data from the pump pressure data storing section  74 , and performs the frequency analysis of the pump pressure waveform. Also, the breaker operation state determining section  76  determines whether the breaker  7  is in the operation state or not based on the pump pressure data from the pump pressure data storing section  74 , the result of the frequency analysis by the pump pressure wave-analysis section  75 , and the state of the pressure switch  53  that is obtained by a pressure switch signal input section  72 . The result of determination is provided to a control mode comparing section  82 , a control mode determining section  84 , and a breaker operation time measuring section  77 . 
     The aforementioned control mode comparing section  82  compares the result of determination by the breaker operation state determining section  76  with the current control mode that is stored by a control mode storing section  83 , and determines whether to provide an alarm command signal. If the control mode comparing section  82  provides the alarm command signal, an alarm is indicated by an alarm indicating section  87 . 
     Also, the aforementioned control mode determining section  84  determines a control mode to be executed based on the result of determination by the breaker operation state determining section  76 , the control mode that is selected by a control mode input section  80 , and the current control mode that is stored by the control mode storing section  83 . An engine pump control section  88  then controls the output of the engine  15 , and the discharge flow rate of the hydraulic pump  16  in accordance with the control mode that is determined by the control mode determining section  84 . 
     Also, if receiving the result of determination that the breaker  7  is in the operation state from the breaker operation state determining section  76 , the breaker operation time measuring section  77  measures the operation time of the breaker  7 . The result of the measurement is stored by a breaker operation time storing section  78 , and is indicated by a breaker operation time indicating section  79 . 
     Also, in the block diagram shown in  FIG. 6 , a supply flow rate determining section  85  is provided with a signal from a supply flow rate setting value input section  81  that sets the flow rate setting value of the pressure oil to be supplied to the breaker  7 . The supply flow rate determining section  85  determines the flow rate of the pressure oil to be supplied to the breaker  7  based on the flow rate setting value by the supply flow rate setting value input section  81 , the current flow rate setting value that is stored by a supply flow rate setting value storing section  86 , and the control mode that is determined by the aforementioned control mode determining section  84 . A supply flow rate control section  89  then controls the flow rate of the pressure oil that is supplied to the breaker  7  based on the flow rate that is determined by the supply flow rate determining section  85 . 
       FIG. 7  is a flow chart showing the processing of the controller according to this embodiment. Note that symbols “S” in  FIG. 7  show steps. 
     In the flow chart shown in  FIG. 7 , if it determined based on an ON signal from the pressure switch  53  that the attachment operation pedal  49  is depressed, it is then determined whether the currently-executed control mode is the breaker mode or not (S 1  and S 2 ). If the currently-executed control mode is not the breaker mode, in other words, is a mode other than the breaker mode (e.g., the active mode), the pump pressure value that is detected by the pressure sensor  48  is monitored at a predetermined period, and the data of the pump pressure value is maintained (S 3 ). The pump pressure data that is latched in Step S 3  is subjected to Fourier transform (fast Fourier transform), and the frequency analysis on the pump pressure waveform is executed (S 4 ). Subsequently, the amplitude center value and the amplitude value of the pump pressure waveform are calculated based on the pump pressure data (S 5 ). After that, if the amplitude center value falls within the range P 10 ×0.9 to P 10 ×1.1, and the amplitude value falls within the range A 10 ×0.9 to A 10 ×1.1, and additionally if a frequency component is included which is not less than twice the power-spectrum average value E 2 , and is not less than E 1  in absolute value, in the frequency range from f 2  (Hz) to f 9  (Hz), it is determined that the breaker  7  is in the operation state, and thus the command signal for indication of an alarm is provided to the monitor panel  54  (S 6  to S 9 ). As a result, an alarm is indicated on the display portion  54   a  of the monitor panel  54 . 
     According to this embodiment, since, if the controller  45  determines that the breaker  7  is in the operation state in the state where the active mode is executed, an alarm is indicated on the display portion  54   a  of the monitor panel  54 , it is possible to urge an operator or the like to switch to the breaker mode. Therefore, it is possible to prevent damage to a machine body, hydraulic equipment, and the like. 
     Note that, although, in this embodiment, an example of the alarm issuing section is provided by the display portion  54   a  that indicates an alarm in response to the command signal from the controller  45 , the present invention is not limited to this. The alarm issuing section may be a buzzer that emits an audible alarm in response to the command signal from the controller  45 , a voice alarm that generates a voice alarm message in response to the command signal from the controller  45 , or the like. In addition to this, the aforementioned display portion  54   a , and the aforementioned buzzer and voice alarm may be suitably combined. In this case, it is possible to further attract the attention of the operator. Furthermore, needless to say, the aforementioned buzzer and voice alarm can be installed inside the monitor panel  54 , or can be disposed separately from the monitor panel  54 . 
     Second Embodiment 
     Basically, hardware configuration according to this embodiment is similar to the hardware configuration shown in  FIG. 2  according to the foregoing first embodiment except that processing of the controller  45  is partially different from the first foregoing embodiment. More specifically, only the processing of Step S 9  in the flow chart shown in  FIG. 7  is different from the first foregoing embodiment. The following description will mainly describe this difference. 
     If it is determined that the breaker  7  is in the operation state in Step S 8 , the electro-hydraulic proportional flow control valve  52  is provided with a command signal that restricts the flow rate of the pressure oil to be supplied from the hydraulic pump  16  to the breaker  7  to not more than the allowable flow rate of the breaker  7  (or zero). Thus, the pilot pressure oil is supplied to the operation portion  36   a  of the attachment operation valve  36  in accordance with the valve opening degree of the electro-hydraulic proportional flow control valve  52  that is adjusted based on the command signal from the controller  45 . As a result, the adjustment of the valve opening degree of the attachment operation valve  36  restricts the flow rate of the pressure oil that is supplied from the hydraulic pump  16  to the breaker  7  to not more than the allowable flow rate of the breaker  7  (or zero). 
     According to this embodiment, since, if the controller  45  determines that the breaker  7  is in the operation state in the state where the active mode is executed, the electro-hydraulic proportional flow control valve  52  restricts the flow rate of the pressure oil to be supplied from the hydraulic pump  16  to the breaker  7  to not more than the allowable flow rate of the breaker  7  (or zero), it is possible to prevent damage to a machine body, hydraulic equipment, and the like. 
     Third Embodiment 
     Basically, hardware configuration according to this embodiment is similar to the hardware configuration shown in  FIG. 2  according to the foregoing first embodiment except that processing of the controller  45  is partially different from the first foregoing embodiment. More specifically, only the processing of Step S 9  in the flow chart shown in  FIG. 7  is different from the first foregoing embodiment. The following description will mainly describe this difference. 
     If it is determined that the breaker  7  is in the operation state in Step S 8 , the active mode is switched to the breaker mode as a control mode to be executed. Accordingly, the following processes (C), (D), (E) and (F) is executed. (C) A command signal that sets regulation shown by the symbol L 2  in  FIG. 3  that is shifted at a predetermined rotational speed on the lower rotational speed side from a regulation line shown by the symbol L 1  in  FIG. 3  that is set as full power operation of the engine  15 . (D) The swash plate control device  47  is provided with the command signal that controls the discharge flow rate of the hydraulic pump  16  so that the output torque of the engine  15  and the absorption torque of the hydraulic pump  16  match to each other at the engine power torque point shown by the symbol TP 2  on the aforementioned regulation line L 2  in  FIG. 3  where fuel consumption is relatively small and engine output is approximately 70% of the rated output. (E) The electro-hydraulic proportional flow control valve  52  is provided with the command signal that restricts the flow rate of the pressure oil to be supplied from the hydraulic pump  16  to the breaker  7  to not more than the allowable flow rate of the breaker  7 . (F) The operation portion  44   a  is provided with a command signal that switches the solenoid switching valve  44  to the position B. 
     Execution of the aforementioned processes (C) and (D) sets the output of the hydraulic pump  16  to a suitable pump output for breaker work. Also, execution of the aforementioned process (E) supplies the pilot pressure oil to the operation portion  36   a  of the attachment operation valve  36  in accordance with the valve opening degree of the electro-hydraulic proportional flow control valve  52  that is adjusted based on the command signal from the controller  45 . As a result, the adjustment of the valve opening degree of the attachment operation valve  36  restricts the flow rate of the pressure oil that is supplied from the hydraulic pump  16  to the breaker  7  to not more than the allowable flow rate of the breaker  7 . Also, execution of the aforementioned process (F) allows the pilot pressure oil from the pilot pressure oil source  35  to act upon the operation portion  43   a  of the switching valve  43  so that the switching valve  43  is switched to from the position A to the position B. As a result, the oil that is returned from the breaker  7  is directly drained into the tank  30 . Note that, since, when the oil that is returned from the breaker  7  is directly drained into the tank  30 , the back pressure of the breaker  7  becomes almost zero, the striking operation by the breaker  7  is more effectively conducted. 
     According to this embodiment, since, if the controller  45  determines that the breaker  7  is in the operation state in the state where the active mode is executed, the active mode is switched to the breaker mode as a control mode to be executed, it is possible to prevent damage to a machine body, hydraulic equipment, and the like. 
     Fourth Embodiment 
     Basically, hardware configuration according to this embodiment is similar to the hardware configuration shown in  FIG. 2  according to the foregoing first embodiment except that processing of the controller  45  is partially different from the first foregoing embodiment. More specifically, only the processing of Step S 9  in the flow chart shown in  FIG. 7  is different from the first foregoing embodiment. The following description will mainly describe this difference. 
     If it is determined that the breaker  7  is in the operation state in Step S 8 , the amount of operation time in which the breaker  7  is in the operation state is measured and the accumulated amount of the operation time is stored. The accumulated amount of the operation time is indicated on the display portion  54   a  of the monitor panel  54 . Note that the accumulated amount of the operation time may be confirmed through a remote terminal device via radiotelegraphy. 
     According to this embodiment, since, if determining that the breaker  7  is in the operation state, the controller  45  measures the amount of operation time in which the working equipment is in the operation state and stores the accumulated amount of the operation time, it is possible to determine the damaged degree of a machine body or the like based on the accumulated amount of the operation time. Therefore, it is possible to optimize the timing of maintenance, rental fee, the estimate of a pre-owned machine, and the like. 
     Note that, although, in the foregoing embodiments, the hydraulic breaker  7  is mounted as an example of working equipment (attachment for work) of the hydraulic shovel  1 , the present invention can be applied to the hydraulic shovel with a hydraulic compactor as working equipment mounted thereto. In this case, though not illustrated, this hydraulic compactor includes a vibration generating device that has a cylinder and a piston that is supplied with the pressure oil from the hydraulic pump and vibrates within the aforementioned cylinder. The hydraulic compactor is configured to suitably perform compaction by means of a compaction plate that receives vibration of the piston that vibrates in the vibration generating device. 
     Fifth Embodiment 
     Although, in the foregoing embodiments, it is determined whether the breaker  7  is in the operation state or not based on the frequency characteristic, and the amplitude center value and the amplitude value of the pump pressure waveform, the type of working equipment can be determined instead of or in addition to the operation state of working equipment. 
     In this embodiment, the controller  45  stores in advance the model data of the amplitude center value, the amplitude value and the frequency characteristic of the pump pressure waveform for each type of working equipment. The controller  45  compares the model data with the amplitude center value, the amplitude value and the frequency characteristic of the pump pressure waveform that are calculated based on pump pressure values that are detected by the pressure sensor  48  (hereinafter, referred to as “detection data”), and determines a currently-mounted working equipment. 
     For example, the controller  45  stores in advance the model data of a breaker (hereinafter, referred to as a “breaker model”) similar to the data shown in the diagram (a) of  FIG. 4  and the diagram (a) of  FIG. 5 , the model data of a bucket for skeleton work (hereinafter, referred to as a “skeleton model”) similar to the data shown in the diagram (b) of  FIG. 4  and the diagram (b) of  FIG. 5 , and the model data of a bucket for dump truck loading work (hereinafter, referred to as a “loading-of-dump-truck model”) similar to the data shown in the diagram (c) of  FIG. 4  and the diagram (c) of  FIG. 5 . The controller  45  compares detection data with the breaker model, the skeleton model and the loading-of-dump-truck model, and searches for model data that matches the detection data. For example, in the case where the detection data matches the breaker model, the controller  45  determines that the breaker is mounted. 
     Note that, as for the “type” used herein, devices of the same working equipment with different specifications are distinguished from each other as different types. For example, the controller  45  can store in advance the model data related to a plurality of breakers with different specifications to compare detection data with the model data related to a plurality of breakers with different specifications, and can determine the type of the breaker. 
     According to this embodiment, the type of working equipment can be determined based on the amplitude center value, the amplitude value and the frequency characteristic of the pump pressure waveform. Therefore, it is possible to surely determine the type of the currently-mounted working equipment. The controller  45  can thus automatically recognize the type of working equipment, and can execute suitable control in accordance with the type of working equipment. 
     Note that comparison between the detection data and the model data is not limited to complete matching, but the determination whether the detection data matches the model data may be made inconsideration of some extent of expected error. 
     Other Embodiments 
     In the foregoing embodiments, although the frequency analysis of the pump pressure waveform has been conducted using fast Fourier transform, the frequency analysis method in the present invention is not limited to this. 
     Also, in the case where the present invention is applied to a known attachment-type hydraulic shovel, there is an advantage that can provide the aforementioned effect by changing the software logic of the controller  45  without mounting any additional component to the hydraulic shovel. 
     The present invention provides an effect that can surely determine whether working equipment such as a hydraulic breaker is in an operation state. Therefore, the present invention is useful for working machines.