Power supply system for electric construction machine

Abstract

The invention provides a power supply system for an electric construction machine, which can prevent a power supply cable from being damaged and improve the working efficiency of the electric construction machine. The power supply system includes a cable reel that pulls out and winds up a power supply cable from an external power source, a reel sensor, a rotation angle sensor that detects a wiring direction of the power supply cable with respect to the electric excavator, a monitor, and a controller. The controller calculates the winding length of the power supply cable wound around the cable reel on the basis of the rotation amount of the cable reel detected by the reel sensor, and causes the monitor to simultaneously display the winding length and the routing direction detected by the rotation angle sensor.

Description

Technical Field

[0001] The present invention relates to a power supply system for an electric construction machine that supplies electric power from an external power supply to the electric construction machine via a power supply cable. Background Art

[0002] An electric excavator, which is one of the electric construction machines, includes, for example, a traveling body, a revolving body rotatably arranged on the upper side of the traveling body, an electric motor mounted on the revolving body, a hydraulic pump mounted on the revolving body and driven by the electric motor, and a hydraulic actuator driven by pressure oil ejected from the hydraulic pump. Some electric excavators are configured to connect a power supply cable to the revolving body side, and supply power from an external power source via the power supply cable. In addition, the electric motor is driven by the power supplied via the power supply cable. Alternatively, a battery mounted on the revolving body is charged by the power supplied via the power supply cable, and the electric motor is driven by the power of the battery.

[0003] When the above-mentioned electric excavator rotates or performs other actions while the power supply cable is connected, the power supply cable may be damaged. Patent document 1 discloses a cable holder for preventing damage to the power supply cable. The cable holder of patent document 1 is installed on the rotating body of the electric excavator in a state that it can rotate around a vertical axis, and guides the power supply cable. In addition, the cable holder rotates in the opposite direction to the rotation of the rotating body, for example, so that an excessive load is not applied to the power supply cable.

[0004] Patent document 2 discloses a power supply system for supplying power to an electric excavator from an external power supply via a power supply cable. The power supply system includes a cable drum for pulling out and winding up the power supply cable from the external power supply, a detection unit for detecting the pulled-out length of the power supply cable pulled out from the cable drum, an alarm unit, and a controller for controlling the alarm unit. The controller controls the alarm unit and issues an alarm when the pulled-out length of the power supply cable detected by the detection unit is the maximum. As a result, the operator moves the electric excavator in a direction close to the external power supply or moves the electric excavator with the power supply cable removed. Therefore, damage to the power supply cable can be suppressed.

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: Japanese Patent Application Publication No. 2018-084099

[0008] Patent Document 2: Korean Patent Publication No. 10-2012-0114879 Summary of the invention

[0009] Problems to be solved by the invention

[0010] If the cable holder of Patent Document 1 is used, damage to the power supply cable can be suppressed. However, although it is not clearly stated in Patent Document 1, the rotation range of the cable holder is limited for reasons such as preventing the cable holder from contacting the cab, etc. Furthermore, when the rotation of the cable holder reaches the limit, if the rotary body of the electric excavator rotates, there is a possibility that the power supply cable will be caught. Therefore, for example, the operator needs to visually check the state of the power supply cable while operating the electric excavator, resulting in reduced work efficiency.

[0011] In addition, if the power supply system of Patent Document 2 is adopted, damage to the power supply cable can be suppressed. However, if the pull-out length of the power supply cable is not maximum, the operator cannot understand the movable range of the electric excavator, which leads to reduced work efficiency.

[0012] The present invention has been made in view of the above-mentioned circumstances, and an object of the present invention is to provide a power supply system for an electric construction machine that can prevent damage to a power supply cable and improve the working efficiency of the electric construction machine.

[0013] Means for solving problems

[0014] In order to achieve the above-mentioned purpose, the power supply system of the electric construction machinery of the present invention supplies power to the electric construction machinery from an external power supply via a power supply cable, and includes: a cable reel, which pulls out and reels in the power supply cable from the external power supply; a reel sensor, which detects a state quantity of the cable reel that changes due to the pulling out and reeling in of the power supply cable; a rotation angle sensor, which detects a wiring direction of the power supply cable relative to the electric construction machinery; a monitor; and a controller, which controls the display on the monitor, the controller calculates the winding length of the power supply cable wound on the cable reel based on the state quantity of the cable reel detected by the reel sensor, and causes the monitor to simultaneously display the winding length and the wiring direction detected by the rotation angle sensor.

[0015] Effects of the Invention

[0016] According to the present invention, it is possible to prevent the power supply cable from being damaged and improve the working efficiency of the electric construction machine. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a diagram showing the configuration of a power supply system in one embodiment of the present invention.

[0018] Figure 2 It is a figure which shows the structure of the cable reel in one embodiment of this invention.

[0019] Figure 3 It is a right side view showing the overall structure of the electric excavator in one embodiment of the present invention.

[0020] Figure 4 It is a rear view showing the overall structure of the electric excavator in one embodiment of the present invention.

[0021] Figure 5 It is a perspective view showing the structure of a cable holder of an electric excavator in one embodiment of the present invention.

[0022] Figure 6 This is a left side view showing the structure of a cable holder of an electric excavator in one embodiment of the present invention.

[0023] Figure 7 This is a diagram showing a configuration related to a boom cylinder in the configuration of a drive device for an electric excavator according to an embodiment of the present invention.

[0024] Figure 8 This is a block diagram showing the configuration of an electric system of an electric excavator according to one embodiment of the present invention together with related devices.

[0025] Fig. 9 This is a flowchart showing the contents of display control of the winding length of the power supply cable in one embodiment of the present invention.

[0026] Fig.10 1 is a flowchart showing the content of display control of the rotation angle of the cable holder in one embodiment of the present invention.

[0027] Fig.11A It is a diagram showing a specific example of a display screen of a monitor of an electric excavator according to one embodiment of the present invention.

[0028] Fig. 11B It is a diagram showing a specific example of a display screen of a monitor of an electric excavator according to one embodiment of the present invention. DETAILED DESCRIPTION

[0029] An embodiment of the present invention will be described with reference to the accompanying drawings.

[0030] Figure 1 It is a diagram showing the configuration of a power supply system in this embodiment. Figure 2 1 is a diagram showing the structure of the cable reel in this embodiment (from Figure 1 (viewed in the direction of arrow II). Figure 3 It is a right side view showing the overall structure of the electric excavator in this embodiment. Figure 4 This is a rear view (from the front) showing the overall structure of the electric excavator in this embodiment. Figure 3 (Figure viewed in the direction of arrow IV). Figure 5 It is a perspective view showing the structure of a cable holder of the electric excavator in the present embodiment. Figure 6 This is a left side view (from the left) showing the structure of the cable bracket of the electric excavator in this embodiment. Figure 5 (Figure observed in the direction of arrow VI).

[0031] The power supply system of this embodiment supplies power from an external power supply 1 (for example, commercial power supply) to an electric excavator 3 (electric construction machine) via a power supply cable 2 , and includes a cable reel 4 for pulling out and winding up the power supply cable 2 from the external power supply 1 .

[0032] The cable drum 4 includes a drum body 5 around which the power supply cable 2 is wound, a support platform 6 that rotatably supports the drum body 5, a spring (not shown) that applies force to the drum body 5, and a drum sensor 7 that detects the amount of rotation of the drum body 5 (hereinafter referred to as the amount of rotation of the cable drum 4). The drum body 5 rotates in one direction against the force of the spring, whereby the power supply cable 2 is pulled out from the drum body 5. Alternatively, the drum body 5 rotates in the opposite direction due to the force of the spring, whereby the power supply cable 2 is wound around the drum body 5. The drum sensor 7 outputs a detection signal to a controller (described in detail later) of the electric excavator 3 via the signal line 8. Therefore, the cable drum 4 also pulls out and reels in the signal line 8.

[0033] The electric excavator 3 includes a traveling body 11, a revolving body 12 provided on the upper side of the traveling body 11 in a revolving manner, and a front side ( Figure 1 and Figure 3 The travel body 11 travels by the rotation of a travel motor (not shown), and the revolving body 12 revolves by the rotation of a revolving motor (not shown).

[0034] The working device 13 includes, for example, a swing column 14 connected to the front side of the swing body 12 so as to be rotatable in the left-right direction, a boom 15 connected to the upper side of the swing column 14 so as to be rotatable in the up-down direction, an arm 16 connected to the front end side of the arm 15 so as to be rotatable in the up-down direction, and a bucket 17 connected to the front end side of the arm 16 so as to be rotatable in the up-down direction. The swing column 14 is rotated by the extension and contraction of the swing cylinder 18, the boom 15 is rotated by the extension and contraction of the boom cylinder 19, the arm 16 is rotated by the extension and contraction of the arm cylinder 20, and the bucket 17 is rotated by the extension and contraction of the bucket cylinder 21.

[0035] The rotating body 12 includes a rotating frame 22 constituting a lower basic structure, a rotating frame 22 disposed on the left side (relative to the left side) of the rotating frame 22, and a rotating frame 22 disposed on the left side (relative to the left side) of the rotating frame 22. Figure 1 and Figure 3 The cab 23 is located on the inner side of the paper and is arranged on the rear side of the revolving frame 22 ( Figure 1 and Figure 3 The left side of the counterweight 24.

[0036] In addition, the rotating body 12 includes: a cable connector 25 disposed on the upper side of the counterweight 24 and capable of connecting the power supply cable 2; a connection sensor 26 (see later described) for detecting the state of connection between the power supply cable 2 and the cable connector 25; Figure 8 ); a signal line connector 27 disposed on the upper side of the counterweight 24 and capable of connecting the signal line 8; and a cable bracket 28 mounted on the upper side of the counterweight 24 and guiding the power supply cable 2 and the signal line 8 in a state that can rotate around a vertical axis.

[0037] The cable holder 28 includes: a pedestal 29 fixed to the counterweight 24; a rotating shaft 30 supported by a bearing (not shown) of the pedestal 29 so as to be rotatable around a vertical axis; a support frame 31 extending in the horizontal direction from the rotating shaft 30; a clamp 32 provided on the front end side of the support frame 31 and holding the power supply cable 2; a plurality of support members 33 arranged on the rotating shaft 30 and the clamp 32 and supporting the signal line 8; and a rotation angle sensor 34 for detecting the rotation angle of the rotating shaft 30 relative to the pedestal 29 (hereinafter referred to as the rotation angle of the cable holder 28). It should be noted that the rotation angle sensor 34 is equivalent to the rotation angle sensor for detecting the wiring direction of the power supply cable relative to the electric engineering machine described in the claims, and is equivalent to the rotation angle sensor for detecting the rotation angle of the cable holder around the vertical axis as the wiring direction of the power supply cable relative to the electric engineering machine.

[0038] For example, when the rotating body 12 rotates in the clockwise direction relative to the traveling body 11 when viewed from above, the rotating shaft 30 and the supporting frame 31 of the cable holder 28 rotate in the counterclockwise direction relative to the rotating body 12 when viewed from above. In addition, for example, when the rotating body 12 rotates in the counterclockwise direction relative to the traveling body 11 when viewed from above, the rotating shaft 30 and the supporting frame 31 of the cable holder 28 rotate in the clockwise direction relative to the rotating body 12 when viewed from above. As a result, an excessive load is not applied to the power supply cable 2 and the signal line 8. However, in order to avoid contact between the supporting frame 31 of the cable holder 28 and the cab 23, etc., the rotation range of the rotating shaft 30 is limited by a stopper not shown in the figure.

[0039] In this embodiment, as the reference value (0 degrees) of the rotation angle of the cable holder 28, the state where the support frame 31 faces the rear of the rotating body 12 is defined (see Figure 1 and Figure 3 to Figure 6 ). Furthermore, when it is defined that the rotation angle of the cable holder 28 increases as the support frame 31 rotates clockwise from the above state, the rotation angle of the cable holder 28 is limited to, for example, 90 degrees (limit value on one side). In addition, when it is defined that the rotation angle of the cable holder 28 increases as the support frame 31 rotates counterclockwise from the above state, the rotation angle of the cable holder 28 is limited to, for example, 90 degrees (limit value on the other side).

[0040] A driver's seat (not shown) for the operator to sit is provided in the cab 23. A travel operating lever / pedal (not shown) that can be operated by the operator is provided in front of the driver's seat. The travel operating lever / pedal indicates the movement of the travel body 11 by operating in the front-rear direction. A swing operating pedal (not shown) that can be operated by the driver is provided on the right side of the travel operating lever. The swing operating pedal indicates the movement of the swing column 14 by operating in the left-right direction.

[0041] On the left side of the driver's seat, there is a work operating lever (not shown) that can be operated by the operator. The work operating lever indicates the movement of the swing body 12 by operating in the left-right direction, and indicates the movement of the arm 16 by operating in the front-back direction. On the right side of the driver's seat, there is a work operating lever 35 (see later described) that can be operated by the operator. Figure 7 The operation lever 35 for operation is operated in the left-right direction to instruct the movement of the bucket 17, and is operated in the front-back direction to instruct the movement of the boom 15.

[0042] A locking lever 36 (see below) is provided on the left side of the driver's seat and can be operated by the operator. Figure 7 ). The locking lever 36 is selectively operated to a locked position and an unlocked position. It should be noted that the locking lever of the present embodiment is a door locking lever of the boarding and alighting opening of the cab 23. When the locking lever is operated to the locked position (upward position), the operator is allowed to board and alight. When the locking lever is operated to the unlocked position (downward position), the operator is prevented from boarding and alighting. A monitor 37 (see below) that can be visually recognized or operated by the operator is provided on the right side and in front of the driver's seat. Figure 8 ).

[0043] The electric excavator 3 includes a drive device that drives a plurality of hydraulic actuators (specifically, the travel motor, the swing motor, the swing cylinder 18 , the boom cylinder 19 , the arm cylinder 20 , and the bucket cylinder 21 described above). Figure 7 This is a diagram showing a configuration related to the boom cylinder 19 in the configuration of the drive device of the electric excavator 3 according to the present embodiment.

[0044] The drive device of this embodiment includes an electric motor 38, a hydraulic pump 39 and a pilot pump 40 driven by the electric motor 38, a control valve 41 that controls the flow (specifically, the direction and flow rate) of the pressure oil from the hydraulic pump 39 to the boom cylinder 19, and an operating device 42 for switching the control valve 41. It should be noted that the operating device 42 is mounted on the cab 23 of the revolving body 12, and the electric motor 38, the hydraulic pump 39, the pilot pump 40 and the control valve 41 are mounted on other parts of the revolving body 12.

[0045] The operating device 42 has the above-mentioned working operating lever 35, a pilot valve 43A that reduces the discharge pressure of the pilot pump 40 and generates a pilot pressure in accordance with the front side operation amount of the working operating lever 35, and a pilot valve 43B that reduces the discharge pressure of the pilot pump 40 and generates a pilot pressure in accordance with the rear side operation amount of the working operating lever 35.

[0046] Furthermore, when the operator operates the operation lever 35 to the front side, the pilot pressure generated by the pilot valve 43A is output to the pressure receiving portion 44A of the control valve 41 in accordance with the operation amount, thereby switching the control valve 41 to the switching position on the right side of the figure. As a result, the boom cylinder 19 is shortened. When the operator operates the operation lever 35 to the rear side, the pilot pressure generated by the pilot valve 43B is output to the pressure receiving portion 44B of the control valve 41 in accordance with the operation amount, thereby switching the control valve 41 to the switching position on the left side of the figure. As a result, the boom cylinder 19 is extended.

[0047] It should be noted that the configuration related to other actuators (specifically, the travel motor, the swing motor, the swing cylinder 18, the arm cylinder 20, and the bucket cylinder 21) is also the same as the configuration related to the boom cylinder 19. That is, the corresponding control valve is switched by the pilot pressure from the corresponding operating device, and the other actuators are operated by the pressure oil from the hydraulic pump supplied through the control valve.

[0048] The drive device of the present embodiment further includes a lock valve 45 provided between all the operating devices and the pilot pump 40 as a lock device that can switch between an ineffective state (lock state) and an effective state (lock release state) of the operation of the electric excavator 3 .

[0049] The locking valve 45 is switched in accordance with the operation of the locking rod 36 described above. Specifically, the locking rod 36 is provided with a locking switch 46. When the locking rod 36 is operated to the locking position (rising position), the locking switch 46 becomes an open state. As a result, since the solenoid portion of the locking valve 45 is not energized, the locking valve 45 becomes a blocking position on the right side of the figure, and the discharge pressure of the pilot pump 40 is not introduced into all operating devices (locked state). Therefore, the driving of all hydraulic actuators is prohibited. On the other hand, when the locking rod 36 is operated to the lock release position (descending position), the locking switch 46 becomes a closed state. As a result, the solenoid portion of the locking valve 45 is energized and the locking valve 45 is switched to the communication position on the left side of the figure, and the discharge pressure of the pilot pump 40 is introduced into all operating devices (lock release state). Therefore, the driving of all actuators is allowed (lock release state). It should be noted that the lock switch 46 corresponds to an operation detection device described in the claims for detecting an effective state and an ineffective state of the operation of the electric construction machine.

[0050] The electric motor 38 is driven by the electric power supplied from the external power source 1 via the power supply cable 2. Alternatively, the battery 47 (see below) charged by the electric power supplied from the external power source 1 via the power supply cable 2 may be driven by the electric power supplied from the external power source 1 via the power supply cable 2. Figure 8 ) is driven by electricity. The electrical system of the electric excavator 3 constructed in this way uses Figure 8 illustrate. Figure 8 This is a block diagram showing the configuration of the electrical system of the electric excavator in this embodiment together with related devices.

[0051] The electrical system of this embodiment includes: a rectifier 48 that converts AC power supplied from an external power source 1 via a power supply cable 2 into DC power; an inverter 49 that controls the rotation speed of an electric motor 38; a switch 50 that switches the connection between the rectifier 48, the inverter 49, and the battery 47; and a controller 51 that controls the switch 50, the inverter 49, the monitor 37, etc. It should be noted that the battery 47, the rectifier 48, the inverter 49, the switch 50, and the controller 51 are mounted on the rotating body 12.

[0052] Although not shown, the controller 51 includes a processor that executes processing according to a program, a memory that stores programs and data, etc. When the connection sensor 26 detects that the power supply cable 2 is connected to the cable connector 25, the controller 51 controls the switch 50 to connect the rectifier 48 to the inverter 49 or the battery 47. In this case, the electric motor 38 is driven by the power supplied from the external power supply 1 via the power supply cable 2.

[0053] Alternatively, when the connection sensor 26 detects that the power supply cable 2 is connected to the cable connector 25, the controller 51 controls the switch 50 to connect the rectifier 48 to the battery 47. As a result, the battery 47 is charged with power supplied from the external power supply 1 via the power supply cable 2. When the connection sensor 26 detects that the power supply cable 2 is not connected to the cable connector 25, the controller 51 controls the switch 50 to connect the inverter 49 to the battery 47. In this case, the electric motor 38 is driven by the power of the battery 47.

[0054] Here, as a feature of the present embodiment, the controller 51 calculates the winding length of the power supply cable 2 wound on the cable drum 4 based on the rotation amount of the cable drum 4 detected by the drum sensor 7. And, the controller 51 performs control to simultaneously display the calculated winding length and the rotation angle of the cable holder 28 detected by the rotation angle sensor 34 (in other words, the wiring direction of the power supply cable 2 relative to the electric excavator 3) on the monitor 37. In the following, the display control of the winding length of the power supply cable 2 and the display control of the rotation angle of the cable holder 28 are explained separately.

[0055] use Fig. 9 Next, the display control of the winding length of the power supply cable 2 will be described. Fig. 9 This is a flowchart showing the contents of the display control of the winding length of the power supply cable in the present embodiment.

[0056] In step S1, the controller 51 determines whether the power cable 2 is connected to the cable connector 25 based on the detection result of the connection sensor 26. In the case where the power cable 2 is connected to the cable connector 25, the process proceeds to step S2. In step S2, the controller 51 calculates the winding length L of the power cable 2 based on the rotation amount of the cable reel 4 detected by the reel sensor 7. Then, the process proceeds to step S3, and the monitor 37 displays the winding length L of the power cable 2. For example, Fig.11A As shown, the display screen 60A of the monitor 37 displays the numerical value of the winding length La of the power cable 2, and the power cable icon 63 between the external power icon 61 and the excavator icon 62 displays the pulled-out length of the power cable 2 pulled out from the cable drum 4 in an image. Fig. 11B As shown, the display screen 60B of the monitor 37 displays the numerical value of the winding length Lb of the power supply cable 2 , and the power supply cable icon 63 between the external power supply icon 61 and the excavator icon 62 displays the pulled-out length of the power supply cable 2 pulled out from the cable drum 4 in an image.

[0057] Proceeding to step S4, the controller 51 determines whether the locking valve 45 is in a locked state according to whether the locking switch 46 is in an open state. When the locking valve 45 is not in a locked state, the process proceeds to step S5. In step S5, it is determined whether the winding length L of the power supply cable 2 is less than a specified value Lth (but Lth>0). When the winding length L of the power supply cable 2 is less than a specified value Lth, the process proceeds to step S6. In step S6, an alarm is issued by displaying a message such as "The winding length of the power supply cable is short" on the monitor 37. It should be noted that when the locking valve 45 is in a locked state (that is, when the action of the electric excavator 3 is in an invalid state), the process does not proceed to steps S5 and S6, and no alarm is issued.

[0058] Thus, the operator can easily check the winding length of the power supply cable 2, and can grasp the movable range of the electric excavator 3 at any timing. Therefore, the working efficiency of the electric excavator 3 can be improved. In addition, when an alarm related to the winding length of the power supply cable 2 is issued, the operator moves the electric excavator 3 in a direction close to the external power source 1, or moves the electric excavator 3 with the power supply cable 2 removed. Therefore, damage to the power supply cable 2 can be suppressed.

[0059] use Fig.10 The display control of the rotation angle of the cable holder 28 will be described. Fig.10 1 is a flowchart showing the contents of the display control of the rotation angle of the cable holder in the present embodiment.

[0060] In step S1, the controller 51 determines whether the power supply cable 2 is connected to the cable connector 25 based on the detection result of the connection sensor 26. If the power supply cable 2 is connected to the cable connector 25, the process proceeds to step S7. In step S7, the controller 51 causes the monitor 37 to display the rotation angle θ of the cable holder 28 detected by the rotation angle sensor 34. For example, Fig.11A As shown in FIG. 6A , the display screen 60A of the monitor 37 displays the rotation angle θa of the cable holder 28 in an image according to the orientation of the cable holder icon 65 relative to the excavator icon 64. Fig. 11B As shown, the display screen 60B of the monitor 37 displays the rotation angle θb of the cable holder 28 in an image according to the orientation of the cable holder icon 65 relative to the excavator icon 64 .

[0061] Entering step S4, the controller 51 determines whether the lock valve 45 is in the locked state according to whether the lock switch 46 is in the on state. If the lock valve 45 is not in the locked state, the process proceeds to step S8. In step S8, it is determined whether the rotation angle θ of the cable holder 28 reaches the set value θth on one side of the rotation direction (in detail, a value pre-set to be located inside the range compared to the limit value on one side that limits the rotation range of the cable holder 28, for example, 80 degrees) or reaches the set value θth on the other side of the rotation direction (in detail, a value pre-set to be located inside the range compared to the limit value on the other side that limits the rotation range of the cable holder 28, for example, 80 degrees). If the rotation angle θ of the cable holder 28 reaches the set value θth on one side of the rotation direction or the set value θth on the other side, the process proceeds to step S9. In step S9, an alarm is issued by displaying a message such as "the rotation angle of the cable holder is large" on the monitor 37. It should be noted that when the lock valve 45 is in the locked state (that is, when the operation of the electric excavator 3 is in the disabled state), the process does not proceed to steps S8 and S9, and no alarm is issued.

[0062] Thus, the operator can easily check the rotation angle of the cable holder 28 and can grasp the movable range of the electric excavator 3 at any timing. Therefore, the working efficiency of the electric excavator 3 can be improved. In addition, when an alarm related to the rotation angle of the cable holder 28 is issued, the operator can move the electric excavator 3 in a direction close to the external power source 1 or move the electric excavator 3 with the power supply cable 2 removed. Therefore, damage to the power supply cable 2 can be suppressed.

[0063] It should be noted that, in the above-mentioned embodiment, the case where the reel sensor 7 detects the rotation amount of the reel body 5 is described as an example, but it is not limited to this, and the state amount of the cable reel 4 that changes according to the pulling out and winding up of the power supply cable 2 may be detected. The reel sensor 7 may also detect the weight of the reel body 5, for example.

[0064] In the above embodiment, the controller 51 causes the monitor 37 (notification device) to display a message as an alarm of the winding length of the power supply cable 2 and the rotation angle of the cable holder 28. However, the present invention is not limited to this, and other notification devices may be used to make notifications. That is, a buzzer or the like may be used to make an alarm.

[0065] In addition, in the above-mentioned embodiment, the drum sensor 7 outputs the detection signal to the controller 51 of the electric excavator 3 via the signal line 8, but the present invention is not limited thereto. The drum sensor 7 may output the detection signal to the controller 51 of the electric excavator 3 via wireless communication. In this case, the cable drum 4 does not pull out or reel in the signal line 8.

[0066] In addition, in the above-mentioned embodiment, the electric construction machine is an electric excavator as an example, but the invention is not limited thereto. That is, any electric construction machine including a traveling body, a revolving body provided on the upper side of the traveling body in a revolving manner, and a working device connected to the revolving body may be used, for example, an electric crane may be used.

[0067] Description of Reference Numerals

[0068] 1External power supply

[0069] 2 Power supply cable

[0070] 3Electric excavator (electric construction machinery)

[0071] 4 Cable reels

[0072] 7 reel sensor

[0073] 11 Traveling body

[0074] 12 Rotating Body

[0075] 28 Cable bracket

[0076] 34Rotation angle sensor

[0077] 37 Monitors

[0078] 46 Lock switch (action detection device)

[0079] 51 Controller

Claims

1. A power supply system for an electric construction machine, which supplies power to the electric construction machine from an external power source via a power supply cable, characterized in that it comprises: a cable reel for pulling out and winding up the power supply cable from the external power source; a reel sensor for detecting a state quantity of the cable reel that changes due to pulling out and winding up the power supply cable; A rotation angle sensor for detecting a wiring direction of the power supply cable relative to the electric engineering machine; Monitor; as well as a controller that controls the display to the monitor, The controller calculates a winding length of the power supply cable wound around the cable reel based on the state quantity of the cable reel detected by the reel sensor, and causes the monitor to simultaneously display the winding length and the wiring direction detected by the rotation angle sensor.

2. The power supply system for electric engineering machinery according to claim 1, characterized in that: A cable bracket is provided, which is mounted on the electric construction machine in a state where it can rotate around a vertical axis and guides the power supply cable. The rotation angle sensor detects a rotation angle of the cable holder around a vertical axis as a wiring direction of the power supply cable relative to the electric construction machine.

3. The power supply system for electric engineering machinery according to claim 2, characterized in that: The cable holder is mounted on a revolving body that is rotatably provided on an upper side of a traveling body in the electric construction machine.

4. The power supply system for electric engineering machinery according to claim 1, characterized in that: When the winding length is equal to or less than a predetermined value or the wiring direction reaches a set value, the notification device performs notification.

5. The power supply system for electric engineering machinery according to claim 1, characterized in that: The controller performs notification by the notification device when the winding length is equal to or less than a predetermined value or when the wiring direction reaches a set value on one side or a set value on the other side of the rotation direction.

6. The power supply system for electric engineering machinery according to claim 2, characterized in that: When the winding length is less than a specified value or the rotation angle of the cable holder reaches a set value on one side of the rotation direction or a set value on the other side, the controller notifies the notifying device. The one side setting value is preset to be inside the range of the limit value on one side limiting the rotation range of the cable holder, and the other side setting value is preset to be inside the range of the limit value on the other side limiting the rotation range of the cable holder.

7. The power supply system for electric engineering machinery according to claim 4, characterized in that: A motion detection device is provided to detect the effective state and the ineffective state of the motion of the electric construction machine. When the operation detection device detects the invalid state of the operation of the electric construction machine, the controller stops the notification device from notifying even when the winding length is less than the prescribed value or the wiring direction reaches the set value.

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