Work machine

Abstract

The present invention is a work machine comprising: a lower traveling body; an upper turning body that is provided so as to be capable of turning relative to the lower traveling body by means of a turning mechanism; a work device that is attached to the upper turning body; an electric device that uses electric power to generate driving energy for operating the lower traveling body, the turning mechanism, and the work device; a power supply port to which a power cable connected to an external power source can be attached and detached; and a power storage device that can be charged by using electric power supplied from the external power source via the power cable connected to the power supply port, and that is capable of discharging power used for generating the driving energy. The control device restricts at the operation of at least one among the lower traveling body, the turning mechanism, and the work device when connection loss of the power cable is detected after the connection detection device detects the connection of the power cable to the power supply port.

Description

Work machinery

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

[0002] In recent years, as a countermeasure against global warming, electric work machines have become known as work machines that do not emit greenhouse gases. These work machines use an electric motor to drive a hydraulic pump, thereby supplying pressurized oil to an actuator to operate the actuator. In such electric work machines, an external power source is sometimes used as one of the power sources for the inverter that controls the electric motor. Specifically, the electric work machine is connected to an external power source installed in a predetermined location via a cable, and the inverter is operated using power supplied from the external power source to drive the electric motor and operate the work machine.

[0003] When a work machine operates an actuator while connected to an external power source via a cable as described above, the cable may be subjected to excessive physical load depending on the operation, for example, if the cable is pulled forcefully by the work machine's swinging motion, or if the work machine runs over the cable while traveling. This could result in damage to the cable, so it is necessary to prevent this as much as possible.

[0004] To address the above-mentioned issues, for example, the technology disclosed in Patent Document 1 is known. Patent Document 1 describes a work machine that includes a detection means for detecting that a power cable is connected to a connector, and a control means for prohibiting or limiting the operation of at least one of the electric drive means when the detection means detects that the power cable is connected to the connector, and that allows the lower traveling body to travel but limits the traveling speed to a low or very slow speed when the detection means detects that the power cable is connected to the connector.

[0005] Japanese Patent No. 5004834

[0006] In the work machine described in Patent Document 1, the traveling speed is limited to a low or very slow speed when the power cable is connected to a connector on the vehicle body, but even under such traveling speed restrictions, the power cable may become detached from the connector and fall off depending on the operation of the work machine. In such a case, if the work machine can continue to operate using power from an internal battery or the like even when the power cable is disconnected, there is still a risk that the operation of the work machine will damage the power cable. However, Patent Document 1 does not take into account the operation when the power cable becomes disconnected, and therefore cannot sufficiently prevent damage to the power cable in such a situation.

[0007] The present invention has been made in consideration of the above points, and its object is to realize a work machine that can prevent damage to the cable that supplies power from a power supply device to the work machine, even if the cable falls off the work machine.

[0008] a power supply port to which a power cable connected to an external power source can be attached; a power storage device that can be charged using power supplied from the external power source via the power cable connected to the power supply port and that can discharge the power used to generate the drive energy; and a control device that controls operation of the lower running body, the swing mechanism, and the work device, wherein the work machine is provided with a connection detection device that detects the connection state of the power cable to the power supply port, and when the control device detects loss of connection of the power cable after the connection detection device has detected that the power cable has been connected to the power supply port, the control device restricts operation of at least one of the lower running body, the swing mechanism, and the work device.

[0009] According to the present invention, even if the cable that supplies power from the power supply device to the work machine falls off from the work machine, damage to the cable can be sufficiently prevented.

[0010] Further features related to the present invention will become apparent from the description of the present specification and the accompanying drawings. In addition, problems, configurations, and effects other than those described above will become apparent from the following description of the embodiments.

[0011] An external view of an electric hydraulic excavator, which is an example of a work machine according to an embodiment of the present invention. A configuration diagram of a control system for a work machine according to a first embodiment of the present invention. A diagram showing a control flow of operation restriction processing. A configuration diagram of a control system for a work machine according to a second embodiment of the present invention. A configuration diagram of a control system for a work machine according to a third embodiment of the present invention.

[0012] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a work machine according to the present invention will now be described in detail with reference to the accompanying drawings, taking a hydraulic excavator as an example.

[0013] 1 is an external view of an electric hydraulic excavator, which is an example of a work machine according to an embodiment of the present invention. The electric hydraulic excavator 1 includes a lower traveling body 2 having a pair of left and right crawlers 5, an upper rotating body 3 provided on the lower traveling body 2 and connected to the lower traveling body 2 via a rotating mechanism 4, a boom 8 rotatably connected to one end of the upper rotating body 3, an arm 9 rotatably connected to one end of the boom 8, and a bucket 10 rotatably connected to one end of the arm 9.

[0014] The lower traveling body 2 is provided with a pair of left and right crawlers 5 each having a travel motor 35 for rotating the crawlers 5. The lower traveling body 2 can perform any one of forward traveling, backward traveling, and direction changes by driving the left and right crawlers 5 to rotate in either the forward or backward direction using the travel motor 35.

[0015] The upper rotating body 3 is provided with a cab 7 in which an operator rides to operate the hydraulic excavator 1. A swing motor 34 (see FIG. 2 ) is provided in a swing mechanism 4 that connects the lower traveling body 2 and the upper rotating body 3. By driving this swing motor 34, the swing mechanism 4 can swing the upper rotating body 3 at any angle relative to the lower traveling body 2.

[0016] In the hydraulic excavator 1, the boom 8, arm 9, and bucket 10 attached to the upper rotating body 3 constitute a work device for performing work such as excavation. The boom 8 and upper rotating body 3 are connected via a boom cylinder 31. The arm 9 and boom 8 are connected via an arm cylinder 32. The bucket 10 and arm 9 are connected via a bucket cylinder 33. In the hydraulic excavator 1, hydraulic pressure is supplied to the boom cylinder 31, arm cylinder 32, and bucket cylinder 33, respectively, to extend and retract these cylinders, thereby operating the boom 8, arm 9, and bucket 10, respectively, to perform work such as excavation.

[0017] A power feed port 90 is provided on the upper rotating body 3. The power feed port 90 has a structure that allows a power cable 92 connected to an external power source 100 installed near the hydraulic excavator 1 to be attached and detached. The hydraulic excavator 1 can receive power from the external power source 100 via the power cable 92 connected to the power feed port 90. The power supplied from the external power source 100 is charged in a storage battery 40 (see FIG. 2 ) built into the hydraulic excavator 1, and is used to generate hydraulic pressure for operating the swing motor 34, the travel motor 35, and each cylinder of the work device (boom cylinder 31, arm cylinder 32, bucket cylinder 33).

[0018] Figure 2 is a configuration diagram of a control system for a work machine according to the first embodiment of the present invention. The control system 200 shown in Figure 2 is a system that controls the operation of the hydraulic excavator 1 shown in Figure 1, and is configured to include the swing motor 34 and travel motor 35, which are hydraulic motors, the boom cylinder 31, arm cylinder 32, and bucket cylinder 33, which are hydraulic cylinders, and the hydraulic pump 50, pilot pump 51, and control valve unit 53 that generate and adjust the hydraulic pressure supplied to these actuators, respectively.

[0019] The hydraulic pump 50 and the pilot pump 51 are mechanically connected to the electric motor 60. The electric motor 60 is driven to rotate using AC power supplied from the inverter 70, thereby driving the hydraulic pump 50 and the pilot pump 51 and causing the hydraulic pump 50 and the pilot pump 51 to generate hydraulic pressure, respectively. The hydraulic pressure generated by the hydraulic pump 50 is output to the control valve unit 53, and the hydraulic pressure generated by the pilot pump 51 is output to the control valve unit 53 via the operation device 21.

[0020] The operating device 21 provided in the cab 7 is disposed between the pilot pump 51 and the control valve unit 53 on the hydraulic circuit. When the operator in the cab 7 operates the lever of the operating device 21, hydraulic pressure is output from the pilot pump 51 to the control valve unit 53 in response to the lever operation, and the control valve unit 53 adjusts the opening from the hydraulic pump 50 to each actuator. As a result, hydraulic pressure generated by the hydraulic pump 50 is supplied to each actuator in response to the lever operation of the operating device 21, and each actuator operates.

[0021] As described above, in control system 200, hydraulic pump 50 and pilot pump 51 are driven by the rotational driving force of electric motor 60 using electricity, thereby supplying hydraulic pressure to travel motor 35, swing motor 34, boom cylinder 31, arm cylinder 32, and bucket cylinder 33, and thereby operating undercarriage 2, swing mechanism 4, and working device (boom 8, arm 9, bucket 10). In other words, electric motor 60 is rotationally driven using electricity, and thereby can generate hydraulic pressure that is supplied from hydraulic pump 50 and pilot pump 51 to the actuators of these devices as drive energy for operating undercarriage 2, swing mechanism 4, and working device.

[0022] An inverter 70 is connected to the electric motor 60. The inverter 70 converts DC power supplied from the power conversion device 80 and the storage battery 40 into AC power and supplies it to the electric motor 60 to rotate and drive the electric motor 60. The power conversion device 80 is connected to an external power source 100 via a power feed port 90 and a power cable 92, and converts AC power supplied from the external power source 100 into DC power and outputs it to the inverter 70 and the storage battery 40. The storage battery 40 is charged with the DC power output from the power conversion device 80 and supplies the charged power to the inverter 70 as needed. The power conversion device 80, the inverter 70, and the storage battery 40 are connected to each other via a power line 41.

[0023] 2 also includes a vehicle body controller 20, a monitor 22, and a position sensor 24. The vehicle body controller 20 is connected to the power conversion device 80, the inverter 70, the storage battery 40, and the hydraulic pump 50 via a signal line 42, and controls these devices by outputting predetermined control signals via the signal line 42. For example, the hydraulic pressure output from the pilot pump 51 to the control valve unit 53 is detected by a pressure sensor 54, and a signal corresponding to the detection result is transmitted to the vehicle body controller 20. The current position of the hydraulic excavator 1 and the positions (attitudes) of the upper rotating body 3 and the work implements (boom 8, arm 9, bucket 10) relative to the lower traveling body 2 are detected by the position sensor 24, and a signal corresponding to the detection result is transmitted to the vehicle body controller 20. Based on these signals transmitted from the pressure sensor 54 and the position sensor 24, the vehicle body controller 20 controls the AC power output from the inverter 70 to the electric motor 60, thereby controlling the rotation speed of the electric motor 60 and adjusting the hydraulic pressure discharged from the hydraulic pump 50 to a predetermined flow rate, and also adjusting the volume of the variable displacement hydraulic pump 50. In addition to this, various other controls for operating the hydraulic excavator 1 can be performed by the vehicle body controller 20.

[0024] A connection detection device 91 is provided between the power feed port 90 and the power conversion device 80. The connection detection device 91 detects when the power cable 92 is connected to the power feed port 90 and transmits a predetermined cable connection signal to the vehicle body controller 20 via the signal line 42. Based on the presence or absence of the cable connection signal transmitted from the connection detection device 91, the vehicle body controller 20 performs an operation restriction process for restricting the operation of at least one of the undercarriage 2, the swing mechanism 4, and the working device in accordance with the connection state of the power cable 92. Details of this process will be described below with reference to FIG. 3 . The connection detection device 91 may mechanically or electrically detect the connection of the power cable 92 to the power feed port 90 using a switch or the like, or may be provided as a function of the power conversion device 80 that detects the input of the external power source 100 to the power conversion device 80.

[0025] 3 is a diagram showing a control flow of the operation restriction process executed in the work machine according to one embodiment of the present invention. The control flow shown in FIG. 3 is executed, for example, by the vehicle controller 20 at predetermined processing intervals.

[0026] In step S10, the vehicle body controller 20 determines whether or not a cable connection signal is being transmitted from the connection detection device 91. If the cable connection signal is being transmitted from the connection detection device 91, it is determined that the power cable 92 is connected to the power feed port 90, and the process proceeds to step S20. If the cable connection signal is not being transmitted from the connection detection device 91, it is determined that the power cable 92 is not connected to the power feed port 90, and the process remains in step S10.

[0027] In step S20, the vehicle body controller 20 determines whether the rotation speed of the electric motor 60 is greater than 0 based on a signal indicating the control state of the electric motor 60 transmitted from the inverter 70. If the rotation speed of the electric motor 60 is greater than 0, it determines that the hydraulic excavator 1 is in operation and proceeds to step S30, whereas if the rotation speed of the electric motor 60 is 0, it determines that the hydraulic excavator 1 is in a non-operating state and returns to step S10.

[0028] In step S30, the vehicle body controller 20 implements operational restrictions when the power cable is connected. Here, the operation of at least one of the undercarriage 2, the swing mechanism 4, and the working device is restricted according to preset restrictions. For example, the vehicle body controller 20 restricts the traveling speed of the undercarriage 2 to a predetermined speed or less. Specifically, when the operator issues a travel command by operating the lever of the operation device 21, the vehicle body controller 20 suppresses the drive speed of the traveling motor 35 to restrict the traveling speed of the undercarriage 2 to a predetermined speed or less. This control can be achieved, for example, by changing the rotation speed command of the electric motor 60 sent to the inverter 70 and restricting the flow rate of hydraulic pressure supplied from the hydraulic pump 50 to the traveling motor 35 via the control valve unit 53 to a predetermined value or less. This prevents the power cable 92 connected to the power feed port 90 from accidentally disconnecting due to the traveling operation of the undercarriage 2.

[0029] The operation restriction when connecting the power cable in step S30 is not limited to the above. As long as the operation of at least one of the lower traveling body 2, the swing mechanism 4, and the working device is restricted and the restriction is effective in preventing the power cable 92 from falling off and ensuring safety during work, the vehicle body controller 20 can impose any operation restriction when connecting the power cable in step S30.

[0030] In step S40, similar to step S10, the vehicle body controller 20 determines whether or not a cable connection signal is being transmitted from the connection detection device 91. If the cable connection signal is being transmitted from the connection detection device 91, it is determined that the power cable 92 connected to the power feed port 90 has not become detached, and the process returns to step S30 to continue restricting operation when the power cable is connected. On the other hand, if the cable connection signal is not being transmitted from the connection detection device 91, it is determined that the power cable 92 has become detached from the power feed port 90, and therefore the connection detection device 91 has detected a loss of connection of the power cable 92, and the process proceeds to step S50.

[0031] In step S50, the vehicle body controller 20 notifies the operator that the power cable 92 has come off. Here, for example, a predetermined notification screen is displayed on the monitor 22 installed in the cab 7, so that the operator can recognize that the power cable 92 has come off from the power feed port 90.

[0032] In step S60, the vehicle body controller 20 implements operation restriction when the power cable is disconnected. Here, the operation of at least one of the undercarriage 2, the swing mechanism 4, and the working device is restricted according to preset restriction content. For example, the vehicle body controller 20 prohibits the undercarriage 2 from traveling or restricts the traveling speed to a predetermined speed or less. Specifically, when the operator issues a travel command by operating the lever of the operation device 21, the vehicle body controller 20 prohibits the driving of the travel motor 35 or reduces its driving speed to restrict the traveling speed of the undercarriage 2 to a predetermined speed or less. This speed restriction may be the same as or different from the speed restriction implemented in step S30 when the power cable is connected. Such control can be implemented, for example, by prohibiting or restricting the output of hydraulic pressure as an operation signal from the pilot pump 51 to the control valve unit 53 via the operation device 21, or by changing the rotation speed command of the electric motor 60 to the inverter 70, thereby stopping or restricting the flow rate of hydraulic pressure supplied from the hydraulic pump 50 to the travel motor 35 via the control valve unit 53 to a predetermined value or less. This prevents the power cable 92 that has fallen off the power supply port 90 from being accidentally stepped on by the lower traveling body 2.

[0033] In addition, when restricting operation in the event of a power cable disconnection as described above, the traveling operation of the lower traveling body 2 in either the forward or reverse direction may be prohibited or limited. Specifically, because the power feed port 90 is provided at the rear end of the upper rotating body 2, the extending direction of the power cable can be estimated from the position (orientation) of the upper rotating body 2. Therefore, traveling operation in the extending direction of the power cable is prohibited or the traveling speed is limited to a predetermined speed or less. Alternatively, based on the positional relationship between the lower traveling body 2 and the external power source 100, traveling operation in either the forward or reverse direction toward the external power source 100 is prohibited or the traveling speed is limited to a predetermined speed or less, and traveling operation in the direction away from the external power source 100 is not limited. In this way, it is possible to effectively prevent the power cable 92 from being stepped on while ensuring the operability of the hydraulic excavator 1 as much as possible.

[0034] Furthermore, instead of or in addition to the traveling operation of the lower traveling body 2, the swing operation of the swing mechanism 4 may be prohibited or restricted. Specifically, when the operator issues a command for a swing operation by operating the lever of the operation device 21, the driving of the swing motor 34 is prohibited or the driving speed thereof is suppressed to limit the swing speed of the upper swing body 3 to a predetermined speed or less. Alternatively, the swing range is limited to a predetermined range based on the positional relationship between the upper swing body 3 and the external power source 100. This makes it possible to prevent the power cable 92 that has fallen off the power feed port 90, workers present around the hydraulic excavator 1, and the like from being entangled in the upper swing body 3 or the working device due to the swing operation of the upper swing body 3.

[0035] The operation restriction in step S60 when the power cable falls off is not limited to the above. The vehicle body controller 20 can implement any operation restriction in step S60 when the power cable falls off, as long as it restricts the operation of at least one of the lower traveling body 2, the swing mechanism 4, and the working device, and is effective in preventing damage to the fallen power cable 92 and ensuring safety during work. The restriction may be the same as or different from the restriction in step S30.

[0036] In step S70, the vehicle body controller 20 determines whether a predetermined release command has been input in response to the notification of the disconnection of the power cable 92 to the operator, which was made in step S50. When, for example, a notification screen such as that described above is displayed on the monitor 22 in response to the disconnection of the power cable 92, the operator performs a predetermined release operation by operating the monitor 22, which is a touch panel, or by operating an operation switch (not shown) installed in the cab 7, after checking the surrounding area for safety as necessary. When a release command is transmitted from the monitor 22 or the operation switch to the vehicle body controller 20 in response to this release operation, the vehicle body controller 20 determines in step S70 that a release command has been input, and proceeds to step S80. On the other hand, if the operator has not performed the release operation and a release command has not been input to the vehicle body controller 20, the process returns to step S40 and repeats the above-described process.

[0037] In step S80, the vehicle body controller 20 releases the operational restrictions imposed when the power cable becomes disconnected. Here, the restrictions imposed in step S60 on the operation of at least one of the lower traveling body 2, the swing mechanism 4, and the working device are released, and the traveling motor 35, the swing motor 34, the boom cylinder 31, the arm cylinder 32, and the bucket cylinder 33 are allowed to operate in accordance with the operation of the operating device 21. As a result, when the operator determines that safety has been ensured in the hydraulic excavator 1, the reduction in work efficiency due to the operational restrictions is eliminated, allowing for efficient work to be performed.

[0038] After the process of step S80 is executed, the control flow of FIG. 3 ends.

[0039] In the control system 200 of this embodiment, by executing the operation control processing as described above in the vehicle body controller 20, it is possible to prevent damage to the power cable 92 while ensuring safety in both the case where the power cable 92 is connected and the case where the power cable 92 has become disconnected.

[0040] According to the first embodiment of the present invention described above, the following advantageous effects are achieved.

[0041] (1) A hydraulic excavator 1 serving as a work machine includes a lower traveling body 2, an upper rotating body 3 connected to the lower traveling body 2 via a swing mechanism 4 and rotatable relative to the lower traveling body 2 by the swing mechanism 4, work equipment (boom 8, arm 9, bucket 10) attached to the upper rotating body 3, an electric device (electric motor 60) that uses electric power to generate drive energy for operating each of the lower traveling body 2, the swing mechanism 4, and the work equipment, a power feed port 90 to which a power cable 92 connected to an external power source 100 can be attached / detached, a power storage device (storage battery 40) that can be charged using electric power supplied from the external power source 100 via the power cable 92 connected to the power feed port 90 and can discharge the electric power used to generate the drive energy, and a control device (vehicle controller 20) that controls the operation of the lower traveling body 2, the swing mechanism 4, and the work equipment. When the vehicle body controller 20 detects loss of connection of the power cable 92 after the power cable 92 is connected to the power feed port 90 (step S40: NO), it restricts the operation of at least one of the undercarriage 2, the swing mechanism 4, and the work device (step S60). In this way, even if the power cable 92, which supplies power from the external power source 100, which is a power supply device, to the hydraulic excavator 1, becomes detached from the hydraulic excavator 1, damage to the power cable 92 can be sufficiently prevented.

[0042] (2) In step S60, the vehicle body controller 20 prohibits the traveling operation of the lower traveling body 2 or limits the traveling speed to a predetermined speed or less, for example. In this way, when the power cable 92 falls out of the power feed port 90, the lower traveling body 2 can be prevented from accidentally running over the power cable 92.

[0043] (3) In step S60, the vehicle body controller 20 may prohibit the traveling operation of the undercarriage 2 in either the forward or reverse direction, or may limit the traveling speed to a predetermined speed or less. In this way, when the power cable 92 falls off the power feed port 90, the operability of the hydraulic excavator 1 can be ensured as much as possible, while effectively preventing the undercarriage 2 from accidentally running over the power cable 92.

[0044] (4) In step S60, the vehicle body controller 20 may prohibit the rotation of the upper rotating body 3 by the rotation mechanism 4 or may limit the rotation range to a predetermined range. In this way, when the power cable 92 falls off from the power feed port 90, it is possible to prevent the power cable 92 or workers around the hydraulic excavator 1 from being entangled in the upper rotating body 3 or a work device due to the rotation.

[0045] (5) When the power cable 92 is connected to the power feed port 90 (step S10: YES), the vehicle body controller 20 restricts the operation of at least one of the lower traveling body 2, the swing mechanism 4, and the working device (step S30). This prevents the power cable 92 connected to the power feed port 90 from accidentally coming off.

[0046] (6) The vehicle body controller 20 may impose different restrictions on the operation of at least one of the lower traveling body 2, the swing mechanism 4, and the working device in the operation restriction when the power cable 92 is connected in step S30 when the power cable 92 is connected to the power feed port 90, and the operation restriction when the power cable is disconnected in step S60 when loss of the power cable 92 is detected. In this way, appropriate operation restrictions can be imposed depending on the respective situations when the power cable 92 is connected and when it is disconnected.

[0047] (7) When the vehicle body controller 20 detects that the power cable 92 has been disconnected (step S40: NO), the vehicle body controller 20 notifies the operator (step S50). In this way, when the power cable 92 has been disconnected from the power supply port 90, the operator can be notified of the disconnection and alerted to the disconnection.

[0048] (8) The hydraulic excavator 1 includes, for example, a touch panel monitor 22 as an input device that accepts input operations from the operator. After notifying the operator in step S50, if the operator performs a predetermined release operation via the monitor 22 (step S70: YES), the vehicle body controller 20 releases the restrictions on the operation of at least one of the undercarriage 2, the swing mechanism 4, and the work device (step S80). As a result, if the operator determines that safety has been ensured in the hydraulic excavator 1, the reduction in work efficiency due to the operation restrictions is eliminated, allowing for efficient work to be performed.

[0049] Second Embodiment In this embodiment, an example will be described in which the operation of a hydraulic excavator 1 is controlled by a system configuration different from that of the control system 200 described in the first embodiment.

[0050] Figure 4 is a configuration diagram of a work machine control system according to a second embodiment of the present invention. The control system 200A shown in Figure 4 differs from the control system 200 in Figure 1 mainly in that the operating device 21 is an electric operating device that transmits an operating signal corresponding to the operation content to the vehicle controller 20, and that an electromagnetic pilot valve 52 is provided in the control valve unit 53. Other aspects, such as the appearance and configuration of the hydraulic excavator 1, the other components of the control system 200A, and the content of the operation restriction processing for each actuator that is performed depending on the connection state of the power cable 92, are the same as those described in the first embodiment. Therefore, below, the operation control of the work machine of this embodiment will be described with reference to the appearance diagram of Figure 1 and the control flow of Figure 3, which were described in the first embodiment, in addition to Figure 4.

[0051] In this embodiment, the operating device 21 transmits an operation signal corresponding to the operation content of the operator to the vehicle body controller 20. The vehicle body controller 20 calculates the opening amount of the electromagnetic pilot valve 52 corresponding to the operation of each actuator based on the operation signal transmitted from the operating device 21, and transmits an electric signal corresponding to the calculation result to the electromagnetic pilot valve 52. As a result, the electromagnetic pilot valve 52 controls the hydraulic pressure supplied from the pilot pump 51 to the control valve unit 53 to control the control valve unit 50, which in turn controls the hydraulic pressure supplied from the hydraulic pump 50 to each actuator, thereby operating each actuator.

[0052] 3, when implementing operation restrictions when the power cable is connected in step S30 or when implementing operation restrictions when the power cable is disconnected in step S60, the vehicle body controller 20 restricts the operation of each actuator by restricting the opening amount of the electromagnetic pilot valve 52. That is, in accordance with the restriction contents that are preset for when the power cable 92 is connected and when it is disconnected, the opening amount of the electromagnetic pilot valve 52 when operating the corresponding actuator is restricted more than when no operation restriction is implemented. In this way, operation restrictions similar to those described in the first embodiment can be implemented.

[0053] According to the second embodiment of the present invention described above, the same effects as those described in the first embodiment are achieved.

[0054] Third Embodiment In this embodiment, an example will be described in which the operation of the hydraulic excavator 1 is controlled by a system configuration different from that of the control system 200 described in the first and second embodiments.

[0055] Figure 5 is a configuration diagram of a construction machine control system according to a third embodiment of the present invention. Control system 200B shown in Figure 5 differs from control system 200A in Figure 4 mainly in that electric motors 31B, 32B, and 33B are provided as power sources for operating boom 8, arm 9, and bucket 10, respectively, instead of boom cylinder 31, arm cylinder 32, and bucket cylinder 33, and that inverters 71, 72, and 73 are connected to electric motors 31B, 32B, and 33B, respectively. Other aspects, such as the external appearance and configuration of hydraulic excavator 1, other components of control system 200B, and the content of the operation restriction process for each actuator that is performed depending on the connection state of power cable 92, are the same as those described in the first and second embodiments. Therefore, below, the operation control of a construction machine according to this embodiment will be described with reference to the external view of Figure 1 and the control flow of Figure 3, which were described in the first embodiment, in addition to Figure 5.

[0056] In this embodiment, as in the first embodiment, the operating device 21 transmits an operation signal to the vehicle body controller 20 in accordance with the operation content of the operator. When operating the undercarriage 2 or the swing mechanism 4 based on the operation signal transmitted from the operating device 21, the vehicle body controller 20 calculates the opening amount of the electromagnetic pilot valve 52 in accordance with these operations and transmits an electric signal in accordance with the calculation result to the electromagnetic pilot valve 52. When operating the work implement, the vehicle body controller 20 calculates the rotation speeds of the electric motors 31B, 32B, and 33B in accordance with the respective operations of the boom 8, the arm 9, and the bucket 10 and transmits rotation speed commands in accordance with the calculation result to the inverters 71, 72, and 73. As a result, the hydraulic pressure supplied from the hydraulic pump 50 to the traveling motor 35 and the swing motor 34 via the control valve unit 53 is controlled, and the drive of the electric motors 31B, 32B, and 33B is controlled, thereby operating each actuator.

[0057] 3 , when implementing operational restrictions when the power cable is connected in step S30 or when implementing operational restrictions when the power cable is disconnected in step S60, the vehicle body controller 20 restricts the operation of each actuator by restricting the opening amount of the electromagnetic pilot valve 52 and the rotational speed of the electric motors 31B, 32B, and 33B. That is, in accordance with the restrictions preset for when the power cable 92 is connected and when it is disconnected, the opening amount of the electromagnetic pilot valve 52 and the rotational speed of the electric motors 31B, 32B, and 33B when operating the corresponding actuator are restricted more than when no operational restrictions are implemented. This allows for operational restrictions similar to those described in the first embodiment.

[0058] According to the third embodiment of the present invention described above, the same effects as those described in the first embodiment are achieved.

[0059] Although the embodiments of the present invention have been described in detail above, the present invention is not limited to the above-described embodiments, and various design modifications can be made without departing from the spirit of the present invention as defined in the claims. For example, the above-described embodiments have been described in detail to clearly explain the present invention, and the present invention is not necessarily limited to those including all of the described configurations. Furthermore, it is possible to replace part of the configuration of one embodiment with the configuration of another embodiment, or to add the configuration of another embodiment to the configuration of one embodiment. Furthermore, it is possible to add, delete, or replace part of the configuration of each embodiment with other configurations.

[0060] 1: Hydraulic excavator 2: Undercarriage 3: Upper rotating body 4: Swing mechanism 5: Crawler 7: Cab 8: Boom 9: Arm 10: Bucket 20: Vehicle controller 21: Operation device 22: Monitor 31: Boom cylinder 32: Arm cylinder 33: Bucket cylinder 34: Swing motor 35: Travel motor 40: Storage battery 41: Power line 42: Signal line 50: Hydraulic pump 51: Pilot pump 52: Electromagnetic pilot valve 53: Control valve unit 54: Pressure sensor 60: Electric motor 70: Inverter 80: Power conversion device 90: Power supply port 91: Connection detection device 92: Power supply cable 100: External power source 200: Control system

Claims

1. A work machine comprising: a lower traveling body; an upper slewing body connected to the lower traveling body via a slewing mechanism and provided so as to be slewingly rotatable with respect to the lower traveling body by the slewing mechanism; a working device mounted on the upper slewing body; an electric device that generates driving energy for operating the lower traveling body, the slewing mechanism, and the working device respectively using electric power; a power supply port to which a power cable connected to an external power supply is detachable; a power storage device that can be charged using the power supplied from the external power supply via the power cable connected to the power supply port and can discharge the power used for generating the driving energy; and a control device that controls the operations of the lower traveling body, the slewing mechanism, and the working device, the work machine further comprising a connection detection device that detects a connection state of the power cable to the power supply port, wherein the control device restricts the operation of at least one of the lower traveling body, the slewing mechanism, and the working device when the connection loss of the power cable is detected after the connection of the power cable to the power supply port is detected by the connection detection device.

2. The work machine according to claim 1, wherein the control device prohibits the traveling operation of the lower traveling body or restricts the traveling speed to a predetermined speed or less when the connection loss of the power cable is detected by the connection detection device.

3. The work machine according to claim 1, wherein the control device prohibits the slewing operation of the upper slewing body by the slewing mechanism or restricts the slewing range within a predetermined range when the connection loss of the power cable is detected by the connection detection device.

4. The work machine according to claim 1, wherein the control device restricts the operation of at least one of the lower traveling body, the slewing mechanism, and the working device when the power cable is connected to the power supply port.

5. The work machine according to claim 4, wherein the control device restricts the operation of at least one of the lower traveling body, the slewing mechanism, and the working device with different contents respectively when the power cable is connected to the power supply port and when the connection loss of the power cable is detected.

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