Work machine

Abstract

Provided is a work machine with improved convenience. An air compressor 10 includes a tank unit 20, a compression unit 40, and a control unit 100. The tank unit 20 stores compressed air. The compression unit 40 sends the compressed air to the tank unit 20. The control unit 100 includes a pressure sensor 108 for detecting the pressure in the tank unit 20. The control unit 100 can execute: compression unit diagnosis control for diagnosing the necessity of performing maintenance on the compression unit 40 on the basis of the drive time of the compression unit 40 and the pressure of the tank unit 20; and tank unit diagnosis control for diagnosing the necessity of performing maintenance on the tank unit 20 on the basis of the elapsed time from the point in time at which driving of the compression unit 40 is stopped and the pressure reduction amount of the tank unit 20.

Description

Work equipment

[0001] The present invention relates to a work machine.

[0002] The air compressor described in Patent Document 1 has an air tank that stores compressed air, a compression unit that compresses the air and supplies it to the air tank, a detection unit that detects current and voltage, and a control unit.

[0003] International Publication No. 2018 / 198672

[0004] An air compressor, which is an example of a work machine, has a compressor unit that compresses air and a tank unit that stores the air compressed by the compressor unit. When the components of the compressor unit wear out, the pressure in the tank unit becomes difficult to increase even if the compressor unit is continuously driven. For this reason, it is necessary to diagnose the wear state of the components of the compressor unit.

[0005] However, when diagnosing the operating condition of an air compressor, the cause of the difficulty in increasing the pressure in the tank section is not limited to wear of the components that make up the compression section, so diagnosing only the compression section is insufficient.

[0006] An object of the present invention is to provide a work machine with improved convenience.

[0007] In one embodiment, the work machine has a tank section that stores compressed air, a compression section that is driven to send compressed air to the tank section, and a control section that includes a pressure detection section that detects the pressure within the tank section, and the control section is capable of executing compression section diagnostic control that diagnoses whether or not maintenance is required for the compression section, and tank section diagnostic control that diagnoses whether or not maintenance is required for the tank section.

[0008] In one embodiment, the work machine has a tank section that stores compressed air, a compression section that is driven to send compressed air to the tank section, and a control section that includes a pressure detection section that detects the pressure within the tank section, and the control section is capable of driving the compression section, stopping the driving of the compression section when the pressure in the tank section becomes higher than a predetermined stop threshold, and performing tank section diagnostic control that diagnoses whether or not maintenance of the tank section is required based on the elapsed time from the point in time when the driving of the compression section was stopped and the amount of pressure drop in the tank section.

[0009] According to the present invention, the convenience of the work machine can be improved.

[0010] 1 is a perspective view showing the appearance of an air compressor according to an embodiment; FIG. 2 is a cross-sectional view showing the internal structure of the air compressor according to an embodiment; FIG. 3 is a front view of the internal structure of the air compressor according to an embodiment, as seen from the front; FIG. 4 is a longitudinal section view of the internal structure of the air compressor according to an embodiment, as seen from the rear; FIG. 5 is a block diagram showing the connection state of each part in the air compressor according to an embodiment; FIG. 6 is an explanatory diagram showing information displayed on a touch panel in the air compressor according to an embodiment; FIG. 7 is a graph showing the relationship between elapsed time and tank pressure in tank diagnostic control in the air compressor according to an embodiment; FIG. 8 is a table showing example messages related to pressure rise time, air leakage, and cumulative operating time set in the air compressor according to an embodiment; FIG. 9 is a flowchart showing each process before diagnosis starts in the air compressor according to an embodiment; FIG. 10 is a flowchart showing each process of compression section diagnosis in the air compressor according to an embodiment; FIG. 11 is a flowchart showing each process of compression section diagnosis in the air compressor according to an embodiment; 1 is a graph showing the relationship between the tank pressure and the elapsed time in an air leak diagnosis of an air compressor according to an embodiment of the present invention;

[0011] Hereinafter, an embodiment of a work machine of the present invention will be described in detail with reference to the drawings. Note that in all drawings referred to for describing the embodiment, the same or substantially the same configurations and elements will be designated by the same reference numerals. Furthermore, as a general rule, configurations and elements that have already been described will not be described repeatedly.

[0012] 1 shows an air compressor 10 as an example of a work machine. The air compressor 10 is capable of supplying compressed air to a pneumatic work machine such as a nail gun. The air compressor 10 has a main body frame 12, a tank unit 20, a compression unit 40, and a control unit 100 (FIG. 5).

[0013] <Main Body Frame> The main body frame 12 includes a pair of handles 16. The main body frame 12 is provided with an operation panel 14. The operation panel 14 is provided with a touch panel 121 ( FIG. 6 ) that can display the remaining capacity of the battery pack 52 (described later) and the internal pressure (MPa) of the tank unit 20. A plurality of legs 18 are provided on the underside of the main body frame 12. The main body frame 12 supports the tank unit 20, the compression unit 40, and the control unit 100 ( FIG. 5 ). An operator can move the air compressor 10 to any installation surface M by grasping and lifting the pair of handles 16.

[0014] <Definition of Directions> The air compressor 10 stands upright on the installation surface M in the up-down direction, which is an example of the vertical direction. The horizontal direction, which is orthogonal to the up-down direction, is defined as the front-rear direction and the left-right direction. In other words, the up-down direction, the left-right direction, and the front-rear direction are all orthogonal to each other. Here, the operation panel 14 is located at the top center of the front end of the air compressor 10. Note that the definitions of the up-down direction, the front-rear direction, and the left-right direction are merely for convenience of explanation.

[0015] 2, the tank unit 20 has a first air tank 22, a second air tank 32, a third air tank 34, and a fourth air tank 36. The first air tank 22, the second air tank 32, the third air tank 34, and the fourth air tank 36 each store compressed air A. The first air tank 22, the second air tank 32, the third air tank 34, and the fourth air tank 36 each extend in the vertical direction relative to the installation surface M (FIG. 1). This makes the installation area of ​​the air compressor 10 smaller than the installation area of ​​a configuration in which multiple air tanks extend horizontally.

[0016] The first air tank 22 and the second air tank 32 are aligned in the left-right direction. The third air tank 34 and the fourth air tank 36 are aligned in the left-right direction. The first air tank 22 and the third air tank 34 are aligned in the front-rear direction. The second air tank 32 and the fourth air tank 36 are aligned in the front-rear direction.

[0017] The first air tank 22, the second air tank 32, the third air tank 34, and the fourth air tank 36 have the same structure, except for their arrangement in the air compressor 10. Therefore, when specifically describing the structure of the tank unit 20, the first air tank 22 will be described, and a specific description of the second air tank 32, the third air tank 34, and the fourth air tank 36 will be omitted.

[0018] 1, the first air tank 22 is a vertically elongated tank that extends in the vertical direction. The first air tank 22 includes a cylindrical portion 23, a lower lid portion 27, and an upper lid portion 28.

[0019] The cylindrical portion 23 is made of a cylindrical steel plate. The cylindrical portion 23 has a central axis along the vertical direction. Both vertical ends of the cylindrical portion 23 are closed by a lower lid portion 27 and an upper lid portion 28. A drain pipe 25 (FIG. 2) for discharging drain (water) stored inside the first air tank 22 and a compression portion 40 (described later) are connected to the cylindrical portion 23.

[0020] The lower lid portion 27 and the upper lid portion 28 are welded to the cylindrical portion 23. That is, the inside of the first air tank 22 is sealed, so that the first air tank 22 can store compressed air A (FIG. 2).

[0021] <Compression Section> As shown in Fig. 2, the compression section 40 is surrounded by the tank section 20. The compression section 40 takes in atmospheric air present outside the air compressor 10. The compression section 40 generates compressed air A by compressing the taken-in air. The compression section 40 then delivers the compressed air A to each air tank in the tank section 20. The compressed air A delivered from the compression section 40 flows into the first air tank 22, the second air tank 32, the third air tank 34, and the fourth air tank 36. In other words, the tank section 20 stores the compressed air A delivered from the compression section 40. Note that air is an example of a gas.

[0022] The compression unit 40 can be driven by a battery pack 52 (FIG. 1). The battery pack 52 is a rechargeable secondary battery. Specifically, the battery pack 52 can be charged by power supplied from a power plug 54 (FIG. 1) connected to a commercial power source. The operating state of the compression unit 40 can be arbitrarily switched by operating the operation panel 14 (FIG. 1).

[0023] As an example, the compression section 40 has a structure that compresses atmospheric air to high pressure in two stages. The compression section 40 has a first compression section 42 that compresses air taken in from the outside, and a second compression section 44 that further compresses the air compressed by the first compression section 42. The first compression section 42 and the second compression section 44 are arranged opposite each other in the left-right direction.

[0024] An eccentric shaft 48 rotated by a motor 46 is rotatably provided between the first compression section 42 and the second compression section 44 .

[0025] The first compression section 42 has a cylindrical cylinder 43A, a columnar piston 43B housed in the cylinder 43A, and a piston ring 43C provided on the outer periphery of the piston 43B. The piston ring 43C slides against the inner periphery of the cylinder 43A as the piston 43B reciprocates. In the first compression section 42, the piston 43B operates within the cylinder 43A as the eccentric shaft 48 rotates, thereby generating compressed air A.

[0026] The second compression section 44 includes a cylindrical cylinder 45A, a columnar piston 45B housed in the cylinder 45A, and a piston ring 45C attached to the outer periphery of the piston 45B. The piston ring 45C slides against the inner periphery of the cylinder 45A as the piston 45B reciprocates. In the second compression section 44, the piston 45B operates within the cylinder 45A as the eccentric shaft 48 rotates, generating compressed air A. The piston rings 43C and 45C are made of rubber. Therefore, they may wear out due to the operation of the pistons 43B and 45B.

[0027] The compressed air A generated by the first compression section 42 and the second compression section 44 flows into the first air tank 22, and then flows into the second air tank 32, the third air tank 34, and the fourth air tank 36. The first air tank 22, the second air tank 32, the third air tank 34, and the fourth air tank 36 are in communication with one another. That is, the internal pressures of the first air tank 22 to the fourth air tank 36 are all maintained at approximately the same pressure.

[0028] The eccentric shaft 48 is rotated by a motor 46. The motor 46 is a brushless motor. The motor 46 is disposed on the axis of the eccentric shaft 48 between the first compression section 42 and the second compression section 44. The motor 46 is rotated by power supplied from a battery pack 52 or a power plug 54 (FIG. 1). The motor 46 is rotated in a predetermined rotational direction at a predetermined rotational speed by a drive circuit 116 (FIG. 5).

[0029] The compression unit 40 also includes a cooling fan 56 that is rotated by the motor 46. The cooling fan 56 functions to cool the first compression unit 42, the second compression unit 44, the battery pack 52 (FIG. 1), the drive circuit 116 (FIG. 5), and the like, which become hotter as the operation time increases.

[0030] 1, the air compressor 10 is provided with, for example, four couplers 64. Air tools such as nail guns that are powered by compressed air A can be connected to the four couplers 64. Pressure reducing valves 62 are provided above the couplers 64 in the air compressor 10.

[0031] 3, the pressure reducing valve 62 is provided with a dial 63, a first flow path section 65, and a second flow path section 67. The dial 63 is rotated by an operator. The first flow path section 65 is located upstream of the pressure reducing valve 62 in the air flow direction. The second flow path section 67 is located downstream of the pressure reducing valve 62 in the air flow direction.

[0032] In the pressure reducing valve 62, the pressure of the compressed air A output from the coupler 64 is adjusted (reduced) by the operator rotating the dial 63. This allows the air tool connected to the coupler 64 to be operated at an appropriate air pressure according to its specifications.

[0033] A pair of connection parts 58 are provided below the coupler 64 of the air compressor 10. Other air compressors can be connected to the connection parts 58. For example, if other air compressors 10 are connected to each of the connection parts 58, the total capacity of compressed air A can be increased three times.

[0034] 2 , the first air tank 22, the second air tank 32, the third air tank 34, and the fourth air tank 36 are connected to one another by, for example, a metal (aluminum) piping section 72. Specifically, the piping section 72 includes a first piping section 73, a second piping section 74, a third piping section 75, a fourth piping section 76, and a fifth piping section 77. Note that the first piping section 73, the second piping section 74, the third piping section 75, the fourth piping section 76, and the fifth piping section 77 may also be made of resin.

[0035] 4, the first flow path portion 65 and the second air tank 32 are connected by a pipe 82. The second flow path portion 67 and the coupler 64 are connected by a pipe 83. The first air tank 22 and the connection portion 58 are connected by a pipe 84. The first flow path portion 65 and the second flow path portion 67 are provided with a pressure sensor 108, which will be described later.

[0036] 3 , the air compressor 10 has a discharge section 92. The discharge section 92 discharges drainage stored in the tank section 20 to the outside. Specifically, the discharge section 92 has an open valve 94, a discharge pipe 96, and a drain cock 98.

[0037] <<Release Valve>> The release valve 94 is provided in the tank unit 20. The discharge pipe 96 extends from the release valve 94 to the outside of the air compressor 10. The drain cock 98 is provided in the release valve 94. The release valve 94 is provided in the second air tank 32, for example. The release valve 94 has a flow path (not shown). The flow path in the release valve 94 is opened and closed by opening and closing the drain cock 98.

[0038] When the drain cock 98 is opened, the release valve 94 is opened, and the compressed air A inside the tank unit 20 is discharged from the release valve 94 through the discharge pipe 96 to the outside of the air compressor 10. When the drain cock 98 is closed, the release valve 94 is closed, and the compressed air A inside the tank unit 20 remains inside the tank unit 20. In this way, the release valve 94 can release the compressed air A inside the tank unit 20.

[0039] <Configuration of Control System> As shown in FIG. 5 , the air compressor 10 has, in addition to the configuration described above, a control unit 100, a power supply control unit 112, an operation circuit 114, a drive circuit 116, a rotation detection circuit 118, an alarm unit 120, an AC power supply unit 126, and a DC power supply unit 128.

[0040] The AC power supply unit 126 is an external power supply to which the power plug 54 (FIG. 1) is connected. The DC power supply unit 128 includes the battery pack 52 (FIG. 1). The power supply control unit 112 controls the supply of power from at least one of the AC power supply unit 126 and the DC power supply unit 128 to each unit of the air compressor 10.

[0041] When the operator operates the operation panel 14 (FIG. 1), the operation circuit 114 outputs an operation signal to the control unit 100. When the operator operates the operation panel 14, the operation mode related to the power supply of the air compressor 10 is switched. The operation modes include a first operation mode that uses the AC power supply unit 126, a second operation mode that uses the DC power supply unit 128, and a third operation mode that switches between the AC power supply unit 126 and the DC power supply unit 128.

[0042] The drive circuit 116 is controlled by the control unit 100 to control the power supply to the motor 46. In other words, the drive circuit 116 drives and stops the motor 46. The rotation detection circuit 118 detects the number of rotations of the motor 46 based on the number of rotation position detections counted within a unit time. The detection result by the rotation detection circuit 118 is output to the control unit 100 as a detection signal.

[0043] <Control Unit> The control unit 100 shown in Fig. 5 functions as a computer. The control unit 100 includes a CPU (Central Processing Unit) 102, a memory unit 104, a storage 106, a pressure sensor 108, and a timer 109. The control unit 100 can control the operation of each unit of the air compressor 10. The memory unit 104 or the storage 106 stores various data including programs executed by the CPU 102. A portion of the memory unit 104 can be used to load the programs. The programs cause the CPU 102 to execute each step described below. The pressure sensor 108 is an example of a pressure detection unit that detects the pressure inside the tank unit 20 (Fig. 2).

[0044] 4 , the pressure sensor 108 has a first pressure sensor 108A provided in the first flow path portion 65 and a second pressure sensor 108B provided in the second flow path portion 67. The first pressure sensor 108A detects the pressure of the compressed air A before the pressure is reduced by the pressure reducing valve 62, i.e., the pressure in the tank portion 20. The second pressure sensor 108B detects the pressure of the compressed air A after the pressure is reduced by the pressure reducing valve 62.

[0045] The pressure information detected by the first pressure sensor 108A and the pressure information detected by the second pressure sensor 108B are stored in the memory unit 104 (FIG. 5). In this embodiment, in diagnosing the operating state of the tank unit 20, the pressure information (pressure value) of the first pressure sensor 108A is used as the pressure information of the pressure sensor 108.

[0046] <Notification Unit> As shown in Fig. 6, the notification unit 120 is configured to receive a signal sent from the control unit 100 (Fig. 5), which will be described later, and notify the diagnosis result. The notification unit 120 is, for example, a touch panel 121 provided on the operation panel 14 (Fig. 1). The touch panel 121 has, for example, a button display unit 122, a mode display unit 123, and a status display unit 124.

[0047] The button display unit 122 displays a start button for starting the compression unit diagnosis and tank unit diagnosis, which will be described later. Note that, when preparations to start the diagnosis have not been completed, the start button is displayed inverted and cannot be operated. The mode display unit 123 displays messages indicating the self-diagnosis mode and messages indicating the operating mode of the air compressor 10. The status display unit 124 displays messages such as the results of each diagnosis, errors, and the status during the diagnosis.

[0048] 5 is capable of executing a start determination control for determining whether or not to start a diagnosis, a compression section diagnosis control for diagnosing whether or not there is wear in the piston rings 43C, 45C (FIG. 2), and a tank section diagnosis control for diagnosing whether or not there is air leakage. Furthermore, the control unit 100 is capable of executing a normal drive control.

[0049] <<Start Determination Control>> As shown in Fig. 7 , the control unit 100 (Fig. 5) sets a start threshold value Ps (MPa) for the pressure in the tank unit 20. Then, before executing the compression unit diagnostic control described below, the control unit 100 executes start determination control to determine whether or not to drive the compression unit 40 (Fig. 5). In determining whether or not to start, the control unit 100 determines that drive of the compression unit 40 can be started if the pressure in the tank unit 20 is equal to or lower than the start threshold value Ps. In other words, the control unit 100 determines that each diagnostic control can be started.

[0050] On the other hand, when the pressure in the tank unit 20 is higher than the start threshold value Ps, the control unit 100 determines that it is not possible to start driving the compression unit 40. In other words, the control unit 100 determines that it is not possible to start each diagnostic control. Note that when the pressure in the tank unit 20 is higher than the start threshold value Ps, the pressure in the tank unit 20 decreases when the operator opens the drain cock 98 (FIG. 1). As a result, if the pressure in the tank unit 20 decreases below the start threshold value Ps, it becomes possible to start the diagnosis.

[0051] <<Compression Unit Diagnostic Control>> Compression unit diagnostic control is control in which the control unit 100 diagnoses whether maintenance of the compression unit 40 is required based on the drive time (s) of the compression unit 40 and the pressure (MPa) of the tank unit 20 .

[0052] After the start determination control, if the control unit 100 determines that diagnosis can be started and receives an instruction to perform a pressure unit diagnosis from the operation circuit 114 (FIG. 5), the control unit 100 drives the compression unit 40. Then, the control unit 100 diagnoses whether maintenance of the compression unit 40 is required based on whether the pressure in the tank unit 20 reaches a predetermined pressure within a predetermined elapsed time ΔT (s).

[0053] Specifically, if the pressure in the tank unit 20 reaches a predetermined pressure within a predetermined elapsed time ΔT (s), the control unit 100 diagnoses that maintenance of the compression unit 40 is not required. If the pressure in the tank unit 20 does not reach the predetermined pressure within the predetermined elapsed time ΔT (s), the control unit 100 diagnoses that maintenance of the compression unit 40 is required. Note that in this embodiment, the control unit 100 causes the notification unit 120 ( FIG. 5 ) to notify the result of the pressure unit diagnostic control, but continues to execute the tank unit diagnostic control regardless of the result of the pressure unit diagnostic control.

[0054] <<Tank section diagnostic control>> Tank section diagnostic control is a control in which the control unit 100 diagnoses whether or not maintenance of the tank section 20 is required based on the elapsed time (s) from the point in time when the operation of the compression section 40 was stopped and the amount of pressure drop (MPa) in the tank section 20.

[0055] 7 shows the relationship between the elapsed time in the tank diagnostic control and the pressure in the tank 20. The tank diagnostic control is executed after the start determination control and the compression section diagnostic control are executed.

[0056] In tank unit diagnostic control, the control unit 100 drives the compression unit 40. If the pressure in the tank unit 20 ( FIG. 5 ) becomes higher than a predetermined stop threshold Pt (MPa) within a predetermined elapsed time ΔT (s), the control unit 100 stops driving the compression unit 40. Then, the control unit 100 diagnoses whether maintenance of the tank unit 20 is required (air leakage) based on the elapsed time ΔT1 from the point in time when driving of the compression unit 40 was stopped and the amount of pressure drop ΔP in the tank unit 20.

[0057] <<Normal Drive Control>> The control unit 100 also performs normal drive control of the air compressor 10. Normal drive control refers to the control unit 100 controlling the drive of the compression unit 40 so that the pressure in the tank unit 20 is within a normal pressure range NP, with a restart threshold Pr (MPa) as the lower limit and a stop threshold Pt as the upper limit. The restart threshold Pr is the lower limit of the pressure in the tank unit 20 when restarting the compression unit 40 is necessary. The stop threshold Pt is the upper limit of the pressure in the tank unit 20 when operation of the compression unit 40 must be stopped. In other words, during normal drive control, the control unit 100 starts drive of the compression unit 40 when the pressure in the tank unit 20 falls below the restart threshold Pr, and stops drive of the compression unit 40 when the pressure in the tank unit 20 exceeds the restart threshold Pr. Here, the start threshold Ps described above is smaller than the restart threshold Pr. However, even if the pressure in the tank section 20 falls below the restart threshold value Pr and the control section 100 starts driving the compression section 40, if the amount of compressed air A consumed by the air tool is greater than the amount of compressed air A produced by the compression section 40, the pressure in the tank section 20 will fall below the restart threshold value Pr.

[0058] 5 transmits a signal indicating either the diagnosis result that the compression section 40 is in a maintenance-requiring state or the diagnosis result that the tank section 20 is in a maintenance-requiring state based on the compression section diagnostic control and the tank section diagnostic control described above. The signal is transmitted to the notification section 120, for example.

[0059] In the compression section diagnostic control, when the driving time of the compression section 40 until the pressure in the tank section 20 reaches the diagnostic pressure threshold is longer than the driving time threshold, and when the amount of pressure drop in the tank section 20 when the elapsed time in the tank section diagnostic control is the elapsed time threshold is equal to or greater than the drop amount threshold, the control unit 100 causes the alarm unit 120 to alert that the tank section 20 is in a state requiring maintenance.

[0060] Furthermore, in the compression section diagnostic control, when the driving time of the compression section 40 until the pressure in the tank section 20 reaches the diagnostic pressure threshold is longer than the driving time threshold, and when the amount of pressure drop in the tank section 20 when the elapsed time is the elapsed time threshold is smaller than the drop amount threshold, the control unit 100 causes the notification unit 120 to notify that the compression section 40 is in a state requiring maintenance.

[0061] 8 shows, as an example of the notification of the diagnostic result, a list of a plurality of messages displayed on the notification unit 120. The list is stored in the storage 106, for example.

[0062] The parameters shown in Fig. 8 are parameters that appear in the diagnostic process described below. The measured pressure rise time is T, the preset standard pressure rise time is Ts, and the pressure rise reference time when drainage has accumulated in the tank unit 20 is Td. Furthermore, the cumulative operating time of the air compressor 10 is Ta. "Air leakage" refers to the presence or absence of air leakage in the compression unit 40. t1, t2, and t3, for example, refer to the time points (boundary values) at which the cumulative operating time Ta is divided into four time regions.

[0063] For example, if the pressure rise time T is longer than the standard pressure rise time Ts and the tank diagnostic control diagnoses "no air leak," it is highly likely that the piston rings 43C, 45C (FIG. 2) are worn. Therefore, a message recommending replacement of the piston rings 43C, 45C is displayed on the notification unit 120. On the other hand, if an air leak is diagnosed, a message recommending inspection of the piping, etc. for air leaks is displayed on the notification unit 120.

[0064] If the pressure rise time T is shorter than the standard pressure rise time Ts and the tank diagnostic control diagnoses "no air leak," there is no abnormality in the wear of the piston rings 43C, 45C or in the air leak. However, if the cumulative operating time Ta is long, a message recommending inspection is displayed on the notification unit 120. On the other hand, if the diagnosis is "air leak," there is no problem with the wear of the piston rings 43C, 45C, but a message recommending inspection of the piping, etc., is displayed on the notification unit 120.

[0065] If the pressure rise time T is shorter than the pressure rise reference time Td and the tank diagnostic control diagnoses "no air leak," there is no abnormality in the wear of the piston rings 43C, 45C or in the air leak. However, a message recommending drainage check (drain discharge) is displayed on the notification unit 120. On the other hand, if an air leak is diagnosed, a message recommending an air leak inspection of the piping, etc., and a drainage check is also displayed on the notification unit 120. Other conditions and display contents are as shown in FIG. 8.

[0066] [Operation of the Present Embodiment] Next, a description will be given of the operation of the air compressor 10. Note that the reference numerals of the components of the air compressor 10 will be referred to in Figs. 1 to 6, and individual reference numbers will be omitted.

[0067] <Diagnostic Processing> Each process shown in Figures 9, 10, 11, and 12 is performed in the control unit 100 by the CPU 102 reading out a diagnostic processing program from the memory unit 104 or the storage 106, expanding it in the memory unit 104, and executing it.

[0068] In step S10, the control unit 100 determines whether the motor 46 is stopped. If the motor 46 is stopped (S10: Yes), the control unit 100 proceeds to step S12. If the motor 46 is operating (S10: No), the control unit 100 proceeds to step S14.

[0069] In step S12, the control unit 100 determines whether the internal pressure of the tank unit 20 is 0.05 (MPa) or less based on the pressure information detected by the pressure sensor 108. If the internal pressure of the tank unit 20 is 0.05 (MPa) or less, the process proceeds to step S16. If the internal pressure of the tank unit 20 is greater than 0.05 (MPa), the process proceeds to step S18.

[0070] In step S14, the control unit 100 issues a request to stop the motor 46. Then, the process proceeds to step S30.

[0071] In step S16, the control unit 100 uses the temperature sensor to determine whether the temperature of the motor 46 and other components is 70° C. or less. If the temperature is 70° C. or less (S16: Yes), the process proceeds to step S20. If the temperature is higher than 70° C. (S16: No), the process proceeds to step S22.

[0072] In step S18, the control unit 100 displays on the touch panel 121 that the tank unit 20 is in a high-pressure state, and requests that air be bled using the drain cock 98. Then, the process proceeds to step S30.

[0073] In step S20, the control unit 100 determines whether the power supply voltage is 85 V or less based on information from the power supply control unit 112. If the power supply voltage is 85 V or less (S20: Yes), the process proceeds to step S24. If the power supply voltage is higher than 85 V (S20: No), the process proceeds to step S26.

[0074] In step S22, the control unit 100 displays on the touch panel 121 that the temperature of the motor 46 and the like is high, and requests a waiting time for natural cooling, and then proceeds to step S30.

[0075] In step S24, the control unit 100 enables the operation of the start button (diagnosis start button) on the touch panel 121. Specifically, the highlighted "Diagnosis Start" is displayed in color, and the operation of the diagnosis start button is permitted. Then, the process proceeds to step S28.

[0076] In step S26, the control unit 100 displays on the touch panel 121 that the battery is in a low voltage state, and requests confirmation of the installation state of the battery pack 52 and the connection state of the power plug 54. Then, the process proceeds to step S30.

[0077] In step S28, the control unit 100 determines whether the diagnosis start button has been operated. If the diagnosis start button has been operated (S28: Yes), the process proceeds to step S32. If the diagnosis start button has not been operated (S28: No), the process proceeds to step S10.

[0078] In step S30, the control unit 100 keeps the diagnosis start button on the touch panel 121 in a highlighted state, making it inoperable, and then proceeds to step S10.

[0079] In step S32, the control unit 100 starts the motor 46. Then, the process proceeds to step S34.

[0080] In step S34, the control unit 100 prepares for the timer 109 to start counting the voltage increase. The voltage increase time (count value) measured by the timer 109 is set to Te. That is, in step S34, Te is set to 0. Then, the process proceeds to step S36.

[0081] In step S36, the control unit 100 acquires the tank pressure P (MPa) of the tank unit 20 based on the output of the pressure sensor 108. Then, the process proceeds to step S38.

[0082] In step S38, the control unit 100 starts counting (Te) by the timer 109. Then, the process proceeds to step S40.

[0083] In step S40, the control unit 100 lights up a diagnosis start button on the touch panel 121. The start button is lit in green, for example, and the process then proceeds to step S42.

[0084] In step S42, the control unit 100 displays a message indicating that the diagnosis is in progress on the touch panel 121. Furthermore, the control unit 100 displays a message to not release the air on the touch panel 121. Then, the process proceeds to step S44.

[0085] In step S44, the control unit 100 determines whether the pressure inside the tank unit 20 is 2 (MPa) or higher based on the output of the pressure sensor 108. If the pressure is 2 (MPa) or higher (S44: Yes), the process proceeds to step S46. If the pressure is lower than 2 (MPa) (S44: No), the process proceeds to step S48.

[0086] In step S46, the control unit 100 determines whether the pressure inside the tank unit 20 is 4.4 MPa or higher based on the output of the pressure sensor 108. If the pressure is 4.4 MPa or higher (S46: Yes), the process proceeds to step S50. If the pressure is lower than 4.4 MPa (S46: No), the process proceeds to step S52.

[0087] In step S48, control unit 100 determines whether the count (Te) by timer 109 is shorter than the first reference time T1 (s) for increasing the pressure to 2.0 (MPa). If the count is equal to or greater than the first reference time T1 (S48: No), control proceeds to step S58. If the count is shorter than the first reference time T1 (S48: Yes), control proceeds to step S42.

[0088] In step S50, the control unit 100 stops the rotation of the motor 46. Then, the process proceeds to step S54.

[0089] In step S52, the control unit 100 determines whether the count (Te) by the timer 109 is shorter than the second reference time T2 (s) for increasing the pressure to 4.4 (MPa). If the count is shorter than the second reference time T2 (S52: Yes), the control unit 100 proceeds to step S46. If the count is equal to or greater than the second reference time T2 (S52: No), the control unit 100 proceeds to step S58.

[0090] In step S54, the control unit 100 displays "Diagnosis in progress" on the start button of the touch panel 121. The start button is lit in blue, for example. Then, the process proceeds to step S56.

[0091] In step S56, the control unit 100 stops the timer 109. Then, the process proceeds to step S60.

[0092] In step S58, the control unit 100 displays on the touch panel 121 that the air leak diagnosis will proceed. At this time, a message is displayed indicating that the pressure rise time is slower than the reference time. In the air leak diagnosis, tank diagnosis control is performed. Then, the process proceeds to step S82.

[0093] In step S60, the control unit 100 acquires the voltage rise time T in step S58 as data, and then proceeds to step S62.

[0094] In step S62, the control unit 100 acquires the cumulative operation time Ta (s) of the air compressor 10. Then, the process proceeds to step S64.

[0095] In step S64, the control unit 100 acquires the average voltage Va (V) during operation of the air compressor 10. Then, the process proceeds to step S66.

[0096] In step S66, the control unit 100 obtains the standard voltage rise time Ts (s) from the memory unit 104. The standard voltage rise time Ts is a time that is preset in accordance with the length of the cumulative operating time Ta. Then, the process proceeds to step S68.

[0097] In step S68, the control unit 100 determines whether the pressure increase time T obtained in step S60 is shorter than the standard pressure increase time Ts obtained in step S66. If the pressure increase time T is shorter than the standard pressure increase time Ts (S68: Yes), the control unit 100 proceeds to step S70. If the pressure increase time T is equal to or longer than the standard pressure increase time Ts (S68: No), the control unit 100 proceeds to step S78.

[0098] In step S70, the control unit 100 acquires from the memory unit 104 the reference pressure increase time Td (s) when drainage accumulates in the tank unit 20. Furthermore, the control unit 100 determines whether the pressure increase time T is shorter than the reference pressure increase time Td. If the pressure increase time T is shorter than the reference pressure increase time Td (S70: Yes), the control unit 100 proceeds to step S72. If the pressure increase time T is equal to or longer than the reference pressure increase time Td (S70: No), the control unit 100 proceeds to step S76.

[0099] In step S72, the control unit 100 displays on the touch panel 121 a message prompting the user to check whether drainage has accumulated in the tank unit 20. At this time, a message indicating that the pressure is increasing too quickly and OK and NG buttons are also displayed. Then, the process proceeds to step S74.

[0100] In step S74, the control unit 100 determines whether drainage has accumulated in the tank unit 20 based on button operation by the operator. Specifically, if the OK button has been operated (S74: Yes), the control unit 100 determines that drainage has not accumulated and proceeds to step S80. On the other hand, if the NG button has been operated (S74: No), the control unit 100 proceeds to step S72. Note that when proceeding from step S74 to step S72, a message instructing the operator to discharge the drainage may be displayed.

[0101] In step S76, the control unit 100 displays a message indicating that the voltage increase is OK on the touch panel 121. Then, the process proceeds to step S80.

[0102] In step S78, the control unit 100 displays a message indicating that boosting is not possible on the touch panel 121. Then, the process proceeds to step S80.

[0103] In step S80, the control unit 100 displays on the touch panel 121 a message indicating that the air leak diagnosis will be performed. At this time, a message is displayed indicating that the pressure rise time is shorter than the reference time. Then, the process proceeds to step S82.

[0104] In step S82, the control unit 100 prepares the timer 109 to start counting. The time counted by the timer 109 in the air leak diagnosis is designated as Tc (s). That is, in step S82, Tc is set to 0. Then, the process proceeds to step S84.

[0105] In step S84, the control unit 100 starts counting Tc using the timer 109. Then, the process proceeds to step S86.

[0106] In step S86, the control unit 100 displays "Diagnosis in progress" on the start button of the touch panel 121. The start button is lit in purple, for example. Then, the process proceeds to step S88.

[0107] In step S88, the control unit 100 displays the message "Checking for air leaks" on the touch panel 121. Then, the process proceeds to step S90.

[0108] In step S90, the control unit 100 determines whether Tc is equal to or greater than 120 seconds. If Tc is equal to or greater than 120 seconds (S90: Yes), the control unit 100 proceeds to step S92. If Tc is less than 120 seconds (S90: No), the control unit 100 repeats step S90.

[0109] In step S92, the control unit 100 acquires the pressure P1 (corresponding to Tc 120) inside the tank unit 20 from the pressure sensor 108. Then, the process proceeds to step S94.

[0110] In step S94, the control unit 100 acquires the pressure PX inside the tank unit 20 from the pressure sensor 108. Then, the process proceeds to step S96.

[0111] In step S96, the control unit 100 determines whether the pressure (P1-PX) is lower than the reference pressure Pa (MPa) for determining air leakage. If the pressure (P1-PX) is lower than the reference pressure Pa (S96: Yes), the control unit 100 proceeds to step S98. If the pressure (P1-PX) is equal to or greater than the reference pressure Pa (S96: No), the control unit 100 proceeds to step S102.

[0112] In step S98, the control unit 100 determines whether the time Tc at the time when the pressure PX is acquired is 420 seconds or more. If the time Tc is shorter than 420 seconds (S98: Yes), the process proceeds to step S100. If the time Tc is 420 seconds or more (S98: No), the process proceeds to step S96.

[0113] In step S100, the control unit 100 displays the diagnosis result "No air leakage" on the touch panel 121. Then, the program ends.

[0114] In step S102, the control unit 100 displays the diagnosis result "Air Leak Present" on the touch panel 121. Then, the program ends.

[0115] <Diagnosis Example> Fig. 13 shows graphs G1, G2, G3, and G4 that represent the relationship between elapsed time and the pressure in the tank portion 20. The first pressure-rise reference time T1 corresponds to the upper limit time for determining whether or not an abnormality exists when the pressure is increased to 2 MPa. The second pressure-rise reference time T2 means the upper limit time for determining whether or not an abnormality exists when the pressure is increased to 4.4 MPa. Td is the pressure-rise reference time when drainage has accumulated in the tank portion 20. Ts is the standard pressure-rise time.

[0116] In the case of graph G1, the first pressure-rise reference time T1 has elapsed before the pressure in the tank section 20 reaches 2 MPa, so the motor 46 is stopped. In this case, the rate of pressure increase relative to the elapsed time is low (pressure increase is slow), so if the pressure continues to increase, unnecessary time will be wasted. Therefore, the diagnosis of the compression section 40 is NG.

[0117] In the case of graph G2, the pressure in the tank section 20 reaches 2 MPa within the first pressure-rise reference time T1, but the second pressure-rise reference time T2 elapses before the pressure in the tank section 20 reaches 4.4 MPa, so the motor 46 is stopped. In this case, too, the degree of pressure increase relative to the elapsed time is low (pressure increase is slow), so the diagnosis of the compression section 40 is NG.

[0118] In the case of graph G3, the pressure in the tank section 20 reaches 2 MPa within the first reference pressure-rise time T1, and the pressure in the tank section 20 reaches 4.4 MPa within the second reference pressure-rise time T2 (within the standard pressure-rise time Ts). Therefore, the diagnosis of the compression section 40 is OK.

[0119] In the case of graph G4, the pressure in the tank unit 20 reaches 4.4 MPa before the reference pressure increase time Td, which is a time before the first reference pressure increase time T1, has elapsed. In this state, the pressure in the tank unit 20 is increasing too quickly, and the volume of the tank unit 20 may be decreasing. In other words, the pressure may be increasing too quickly because a large amount of drainage has accumulated in the tank unit 20. For this reason, a warning indicating that drainage has accumulated in the tank unit 20 may be displayed on the touch panel 121 (FIG. 5).

[0120] FIG. 14 shows a graph G5 that indicates the state in which the pressure in the tank portion 20 reaches 4.4 MPa at time T4, and a graph G6 that indicates the change in the power supply voltage up to time T4.

[0121] As shown in graph G6, when the power supply voltage drops at time T3 (<T4) while the air compressor 10 is operating, the time required to increase the pressure in the tank unit 20 becomes longer than when the power supply voltage does not drop. Here, the average voltage Va, which is the power supply voltage per unit time, is defined. Furthermore, a table of standard voltage increase times Ts corresponding to each of a plurality of average voltages Va is prepared in advance. Then, by determining the standard voltage increase time Ts ( FIG. 13 ) according to the average voltage Va obtained by actual measurement, each diagnosis can be performed appropriately even when the power supply voltage drops.

[0122] 15 shows nine standard voltage rise times Ts (Ts1 to Ts9) when the average voltage Va (V) is divided into three stages and the cumulative operating time Ta (s) of the air compressor 10 is divided into three stages. In this way, it is preferable to change the standard voltage rise time Ts depending on the cumulative operating time Ta of the air compressor 10 and the average voltage Va during operation.

[0123] As an example, when the cumulative operating time Ta is equal to or greater than Ta1 but less than Ta2, and the average voltage Va is equal to or greater than Va1 but less than Va2, a standard voltage increase time Ts or Ts5 is set. If the elapsed time required for voltage increase is shorter than Ts5, the system is diagnosed as "no abnormality." If the elapsed time is Ts5 or greater, the system is diagnosed as "abnormal" and "inspection required."

[0124] FIG. 16 shows graphs G7 and G8 that represent the relationship between time (count value, Tc) and pressure in the tank unit 20 when diagnosing an air leak. Note that time Tc is any time between 120 s and 420 s, designated TX (s). The reference time used in diagnosing an air leak is 420 s. The pressure in the tank unit 20 at the start of the diagnosis (Tc = 0) is set to 4.4 MPa, and the pressure in the tank unit 20 at Tc = 120 s is designated P1.

[0125] In graph G7, the pressure in the tank unit 20 at Tc. TX is designated as PX1. In graph G8, the pressure in the tank unit 20 at Tc. 420 s is designated as PX2. Pressures PX1 and PX2 are examples of pressure PX. Pressure range AP refers to the range of pressures that serves as the reference for air leak diagnosis corresponding to time TX.

[0126] Immediately after the motor 46 is stopped, the temperature of the air in the tank unit 20 is high, and as the temperature of the air drops, the pressure in the tank unit 20 also drops. For this reason, the pressure P1 (MPa) in the tank unit 20 120 seconds after the motor 46 is stopped is obtained and used to diagnose an air leak. Note that the pressure range AP is set, for example, from pressure PX1 to pressure P1.

[0127] In the case of graph G7, the pressure in the tank unit 20 falls below the pressure range AP within the reference time of 420 s, so the control unit 100 diagnoses that "there is an air leak." In the case of graph G8, the pressure in the tank unit 20 falls within the pressure range AP within the reference time of 420 s, so the control unit 100 diagnoses that "there is no air leak."

[0128] <Summary of Operation> As explained above, in the diagnosis of the compression unit in the air compressor 10, whether maintenance of the compression unit 40 is required is diagnosed based on the operating time of the compression unit 40 and the pressure in the tank unit 20. If the pressure in the tank unit 20 does not increase to a predetermined pressure even after operating the compression unit 40 for a long time, it is diagnosed that maintenance of the compression unit 40 is required. Note that if the pressure in the tank unit 20 does not increase to a predetermined pressure even after operating the compression unit 40 for a long time, this does not necessarily mean that the compression unit 40 is the cause. For example, if there is a problem with air leakage in the tank unit 20, it will be difficult to increase the pressure in the tank unit 20 to a predetermined pressure even if the compression unit 40 is operated for a long time.

[0129] Here, in the tank section diagnostic control of the air compressor 10, whether or not maintenance of the tank section 20 is required is diagnosed based on the time elapsed since the operation of the compression section 40 was stopped and the amount of pressure drop in the tank section 20. In other words, the presence or absence of air leakage in the tank section 20 is diagnosed. As a result, if the pressure does not rise to a predetermined pressure in the compression section diagnosis, it can be determined that the cause is the tank section 20, not the compression section 40.

[0130] In this way, by performing tank section diagnostic control in addition to compression section diagnostic control, it is possible not only to determine whether or not there is a malfunction in the air compressor 10, but also to isolate the cause of the malfunction (identify the location of the malfunction), thereby improving the convenience of the air compressor 10.

[0131] In the air compressor 10, before executing the compression unit diagnostic control, it is determined whether or not the compression unit 40 can be driven. Then, the compression unit 40 can be driven only when the pressure in the tank unit 20 is equal to or lower than the start threshold value Ps. This allows the initial pressure in the tank unit 20 when starting the compression unit diagnostic control to be consistent at a pressure equal to or lower than the start threshold value Ps every time, thereby enabling appropriate compression unit diagnosis. Furthermore, by consistent initial pressures at the start of the compression unit diagnosis, conditions such as temperature at the end of the compression unit diagnosis can also be consistent, allowing appropriate tank unit diagnostic control.

[0132] In the air compressor 10, the start threshold Ps of the pressure in the tank unit 20 is set to a value smaller than the restart threshold Pr within the normal pressure range NP, so there is no need to unnecessarily increase the pressure in the tank unit 20 when starting a diagnosis. This makes it possible to prevent the compression unit 40 from being driven unnecessarily.

[0133] In the air compressor 10, the compressed air A remaining inside the tank section 20 is released by opening the release valve 94, so diagnosis can be performed by setting the start threshold for the pressure in the tank section 20 to a value close to 0 (zero).

[0134] In the air compressor 10, the control unit 100 sends a signal to selectively display either the diagnostic result of the compression unit 40 or the diagnostic result of the tank unit 20. As a result, if the signal is received within the air compressor 10, the diagnostic result can be displayed in the air compressor 10, and if the signal is received by an external device outside the air compressor 10, the diagnostic result can be displayed in the external device, thereby improving the convenience of the work machine.

[0135] If the diagnosis result of the compression section 40 indicates a maintenance-required state and the diagnosis result of the tank section 20 indicates a maintenance-required state, it is clear that an air leak is occurring at least in the tank section 20. Therefore, the diagnosis result of the tank section 20 is considered to be correct.

[0136] On the other hand, it is highly likely that the reason it took so long for the pressure to rise in the compression section 40 was due to air leakage in the tank section 20. Therefore, if the tank section 20 is serviced, the maintenance-required state of the compression section 40 may be resolved. For these reasons, if the diagnosis result of the compression section 40 indicates a maintenance-required state and the diagnosis result of the tank section 20 indicates a maintenance-required state, it is sufficient to notify the tank section 20 that it is in a maintenance-required state.

[0137] Next, if the diagnosis result of the compression unit 40 indicates a maintenance-required state and the diagnosis result of the tank unit 20 does not indicate a maintenance-required state, the diagnosis result of the compression unit 40 is considered to be correct because there is no air leakage from the tank unit 20. In this case, it is sufficient to notify the user that the compression unit 40 is in a maintenance-required state. In this way, the air compressor 10 can appropriately notify the user of the diagnosis results of the compression unit 40 and the tank unit 20.

[0138] In the air compressor 10, if the pressure in the tank section 20 does not become higher than a predetermined shutdown threshold within a predetermined time, it can be diagnosed that maintenance of the compressor section is necessary.

[0139] In the tank section diagnostic control, the need for maintenance of the tank section 20 is diagnosed based on the time elapsed since the drive of the compression section 40 was stopped and the amount of pressure drop in the tank section 20. In other words, the presence or absence of air leakage in the tank section 20 is diagnosed. As a result, if the pressure does not rise above a predetermined stop threshold Pt, it is determined that the cause is the tank section 20, not the compression section 40. In this way, the compression section 40 can be diagnosed while the tank section diagnostic control is being performed.

[0140] Furthermore, by performing the start control, it is possible to make the pressure in the tank unit 20 at the start of the diagnosis uniform at the same level every time, and therefore it is possible to detect the degree of pressure increase with high accuracy. In this way, the convenience of the air compressor 10 can be improved. However, even if the start control is not performed, the control unit 100 can perform the tank unit diagnosis control, although some error may occur.

[0141] [Modifications of the Present Embodiment] The present embodiment is not limited to the above embodiment, and various modifications are possible without departing from the spirit of the present embodiment. Modifications of the present embodiment will be described below.

[0142] The number of air tanks serving as the tank unit 20 in the air compressor 10 is not limited to four, but may be one, two, three, five or more. The compression unit 40 is not limited to one that performs compression in two stages, but may be one that performs compression in one stage, or three or more stages.

[0143] In the air compressor 10, it is not necessary to perform the start determination to determine whether or not to drive the compression unit 40 before performing the compression unit diagnostic control. The start threshold value Ps may be equal to the restart threshold value Pr.

[0144] The compressed air A inside the tank 20 may be released not only by the release valve 94 but also by a coupler 64 or the like.

[0145] The destination of the signal of the diagnosis result is not limited to the notification unit 120 (touch panel 121), but may also be a mobile terminal 132 (FIG. 17) described later.

[0146] The notification of the diagnosis result by the notification unit 120 is not limited to notification by displaying a message, but may be notification by voice, or notification may be made by lighting or not lighting a lamp of the target item.

[0147] 17 shows a work machine diagnostic system 130. As an example, the work machine diagnostic system 130 includes a mobile terminal 132 and an air compressor 10 capable of wireless communication with the mobile terminal 132. The air compressor 10 is provided with a wireless communication unit 134. The wireless communication unit 134 performs short-range wireless communication with the mobile terminal 132 using Bluetooth (registered trademark) or the like.

[0148] The mobile terminal 132 is an example of an external device, and is a mobile communication device such as a smartphone or a tablet terminal. The mobile terminal 132 has, as an example, a touch panel 121. The mobile terminal 132 can transmit an operation start signal for diagnostic control in the control unit 100 ( FIG. 5 ) to the wireless communication unit 134, and can also receive and display information on the diagnostic results.

[0149] The control unit 100 is capable of executing the compression unit diagnostic control and the tank unit diagnostic control described above. Furthermore, the control unit 100 is capable of transmitting information on each diagnostic result to the mobile terminal 132. In this manner, each diagnosis of the air compressor 10 may be performed through communication with devices external to the air compressor 10. Note that, in the compression unit diagnostic control, the control unit 100 may use information on noise and vibrations generated in the compression unit 40 due to wear of the piston rings 43C and 45C, instead of using the drive time of the compression unit 40 and the pressure in the tank unit 20. Furthermore, in the tank unit diagnostic control, the control unit 100 may use information on noise and vibrations generated in the tank unit 20 due to air leakage, instead of using the elapsed time since the drive of the compression unit 40 was stopped and the amount of pressure drop in the tank unit 20.

[0150] <Note> A work machine diagnostic system having a mobile terminal and a work machine capable of wireless communication with the mobile terminal, the work machine having a tank section that stores compressed air, a compression section that is driven to send the compressed air to the tank section, a control section that includes a pressure detection section that detects the pressure inside the tank section, and a wireless communication section that is capable of wireless communication with the mobile terminal, the mobile terminal being capable of sending to the wireless communication section a signal to start operation of diagnostic control in the control section and also being capable of receiving and displaying information on the diagnosis result, the control section being capable of executing compression section diagnostic control that diagnoses whether or not maintenance of the compression section is required based on the drive time of the compression section and the pressure in the tank section, and tank section diagnostic control that diagnoses whether or not maintenance of the tank section is required based on the elapsed time since drive of the compression section was stopped and the amount of pressure drop in the tank section.

[0151] DESCRIPTION OF SYMBOLS 10...air compressor, 12...main body frame, 14...operation panel, 16...handle, 18...legs, 20...tank section, 22...first air tank, 23...cylindrical section, 25...drain piping, 27...lower cover section, 28...upper cover section, 32...second air tank, 34...third air tank, 36...fourth air tank, 40...compression section, 42...first compression section, 43A...cylinder, 43B...piston, 43C...piston ring, 44...second compression section, 45A...cylinder, 45B...piston, 45C...piston ring , 46...motor, 48...eccentric shaft, 52...battery pack, 54...power plug, 56...cooling fan, 58...connection portion, 62...pressure reducing valve, 63...dial, 64...coupler, 65...first flow path portion, 67...second flow path portion, 72...piping portion, 73...first pipe, 74...second pipe, 75...third pipe, 76...fourth pipe, 77...fifth pipe, 82...piping, 83...piping, 84...piping, 92...discharge portion, 94...open valve, 96...discharge pipe, 98...drain cock, 100...control portion, 102...CPU, 104...mechanical Memory section, 106...storage, 108...pressure sensor, 108A...first pressure sensor, 108B...second pressure sensor, 109...timer, 112...power supply control section, 114...operation circuit, 116...drive circuit, 118...rotation detection circuit, 120...alarm section, 121...touch panel, 122...button display section, 123...mode display section, 124...status display section, 126...AC power supply section, 128...DC power supply section, 130...work machine diagnostic system, 132...portable terminal, 134...wireless communication section, A...compressed air, AP...pressure range, M...installation surface, NP...normal pressure range, P...tank pressure, P1...pressure, Pa...reference pressure, Pr...restart threshold, Ps...start threshold, Pt...stop threshold, PX...pressure, PX1...pressure, PX2...pressure, T...pressure rise time, T1...first reference pressure rise time, T2...second reference pressure rise time, T3...time, T4...time, Ta...cumulative operating time, Tc...time, Td...reference pressure rise time, Ts...standard pressure rise time, TX...time, Va...average voltage, ΔP...pressure drop amount, ΔT...elapsed time, ΔT1...elapsed time

Claims

1. A work machine having a tank section for storing compressed air, a compression section for sending compressed air to the tank section, and a control section including a pressure detection section for detecting the pressure within the tank section, wherein the control section is capable of executing compression section diagnostic control for diagnosing whether or not maintenance is required for the compression section, and tank section diagnostic control for diagnosing whether or not maintenance is required for the tank section.

2. The work machine according to claim 1, wherein the control unit performs diagnostic control of the compression unit based on the drive time of the compression unit and the pressure of the tank unit.

3. A work machine as described in claim 1, wherein the control unit performs diagnostic control of the tank section based on the amount of pressure drop in the tank section and the elapsed time from the point in time when the drive of the compression section was stopped.

4. A work machine as described in claim 2 or 3, wherein the control unit is capable of executing a start feasibility determination to determine whether or not the compression unit can be operated before executing the compression unit diagnostic control, and in the start feasibility determination, the control unit determines that operation of the compression unit can be started if the pressure in the tank unit is equal to or lower than a start threshold, and determines that operation of the compression unit cannot be started if the pressure in the tank unit is higher than the start threshold.

5. The work machine described in claim 4, wherein the control unit performs normal drive control to start driving the compression unit when the pressure in the tank section falls below a restart threshold and to stop driving the compression unit when the pressure in the tank section exceeds a stop threshold, the start threshold being smaller than the restart threshold.

6. A work machine as described in claim 5, wherein the tank portion is provided with an open valve capable of releasing the compressed air inside the tank portion.

7. A work machine as described in claim 1, wherein the control unit sends a signal to display either a diagnosis result that the compression unit is in a state requiring maintenance or a diagnosis result that the tank unit is in a state requiring maintenance based on the compression unit diagnostic control and the tank unit diagnostic control.

8. A work machine as described in claim 7, further comprising an alarm unit capable of receiving the signal and notifying the diagnosis result, wherein the control unit causes the alarm unit to display a maintenance required state when, in the compression unit diagnostic control, the drive time of the compression unit until the pressure of the tank unit reaches the diagnostic pressure threshold is longer than the drive time threshold and, in the tank unit diagnostic control, the amount of pressure drop in the tank unit when the elapsed time from the time when drive of the compression unit was stopped is equal to or greater than the elapsed time threshold, and causes the alarm unit to display a maintenance required state when, in the compression unit diagnostic control, the drive time of the compression unit until the pressure of the tank unit reaches the diagnostic pressure threshold is longer than the drive time threshold and, in the tank unit diagnostic control, the amount of pressure drop in the tank unit when the elapsed time is equal to the elapsed time threshold is smaller than the elapsed amount threshold.

9. A work machine having a tank section for storing compressed air, a compression section for driving to send compressed air to the tank section, and a control section including a pressure detection section for detecting the pressure within the tank section, wherein the control section drives the compression section, stops driving the compression section when the pressure in the tank section becomes higher than a predetermined stop threshold, and performs tank section diagnostic control to diagnose whether or not maintenance is required for the tank section based on the elapsed time from the point in time when the driving of the compression section was stopped and the amount of pressure drop in the tank section.

10. The control unit is capable of executing start control that enables the start of operation of the compression unit when the pressure in the tank unit is equal to or lower than a start threshold value, and does not enable the start of operation of the compression unit when the pressure in the tank unit is higher than the start threshold value, and is capable of stopping the operation of the compression unit and executing the tank unit diagnosis control when the pressure in the tank unit becomes higher than the predetermined stop threshold value within a predetermined time after operation of the compression unit has started by the start control.

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