Electric work machine

Abstract

This electric work machine comprises a vehicle body. The vehicle body includes batteries 112A to 112D, an electric motor, and an inverter for supplying electric power from the batteries 112A to 112D to the electric motor. The electric work machine includes: hub boxes 151A11, 151A12 connected to the batteries 112A to 112D; and a hub box 151B1 connected to the hub boxes 151A11, 151A12 and the inverter. An output unit of the hub boxes 151A11, 151A12 to the hub box 151B1, an input unit of the hub box 151B1 from the hub boxes 151A11, 151A12, and an output unit of the hub box 151B1 to the inverter are respectively provided with a connector 151S, a connector 152N, and a connector 152S. The connection between the hub boxes 151A11, 151A12 and the hub box 151B1 and the connection between the hub box 151B1 and the inverter are established by a cable 154 or the like via the connector 151S, the connector 152N, and the connector 152S. Thus, an electric work machine capable of easily changing the system output is provided.

Description

electric work machine

[0001] The present invention relates to an electric work machine, and more particularly to an electric work machine provided with a power relay device that relays power when power is supplied from a battery to an inverter.

[0002] Recently, from an environmental perspective, electrically powered working machines are increasingly being used. Some electric working machines are driven by a system in which a portion of the electric power used is supplied from a battery mounted on the machine. In this case, direct current from the battery is converted to alternating current by an inverter, which then drives an electric motor to operate the electric working machine. In this case, a power relay device that relays power may be used to transmit power from the battery to the inverter.

[0003] Patent Document 1 discloses a configuration in which a power supply unit is provided in the main body of a construction machine, the power supply unit comprising: a main battery; an auxiliary battery that receives, stores, and outputs surplus power from the main battery; an inverter that has an output section and converts direct current into alternating current; and a repeater that is interposed between the main battery and auxiliary battery, sends surplus power from the main battery to the auxiliary battery, prevents backflow, and sends the stored power in the auxiliary battery to the inverter when necessary.

[0004] Japanese Patent Application Publication No. 11-8945

[0005] When an electric work machine performs work such as excavation or traveling, the work is usually performed under a load assumed at the rated output. However, situations may arise where work is required under a heavy load that cannot be handled by the rated output. For an electric work machine that operates on electricity, it is conceivable to temporarily increase the system output above the rated output by changing the number of onboard batteries that serve as the power source to handle work under heavy loads. However, when the system output is changed by increasing or decreasing the number of onboard batteries, the change in vehicle weight due to the increase or decrease in the number of batteries changes the center of gravity of the vehicle, which may impair vehicle stability and affect work. Furthermore, changing the output may require changing the wiring connecting to the batteries. However, changing the wiring depending on the work is cumbersome, and there is a risk of electric shock if the operator touches the battery terminals. The present invention has been made in consideration of these problems, and its purpose is to provide an electric work machine that allows the system output to be easily changed.

[0006] In order to solve the above problems, the present invention provides an electric work machine having a vehicle body, the vehicle body including a battery, an electric motor, and an inverter that supplies power from the battery to the electric motor, the electric work machine having a first power relay device connected to the battery and a second power relay device connected to the first power relay device and the inverter, the electric work machine being characterized in that an output portion of the first power relay device to the second power relay device, an input portion of the second power relay device from the first power relay device, and an output portion of the second power relay device to the inverter are each provided with a connector, and the first power relay device and the second power relay device and the inverter are connected by cables via the connectors. In this case, an electric work machine can be provided in which a plurality of power relay devices that supply power from the battery to the inverter are provided, and by replacing a power relay device that is not directly connected to the battery with one having a different wiring, a system output can be easily changed.

[0007] Here, for example, the battery and the first power relay device are connected by a cable via terminals or connectors provided on each of them. In this case, the connection between the battery and the first power relay device can be facilitated. Also, for example, the output portion of the battery to the first power relay device is a terminal, and the input portion from the battery to the first power relay device is a connector. In this case, the connection between the battery and the first power relay device can be further facilitated. Furthermore, for example, multiple batteries are provided, the first power relay device is connected to each of the multiple batteries, and the second power relay device changes the series-parallel connection of the multiple batteries. In this case, an appropriate output change depending on the work can be easily performed. Furthermore, for example, multiple batteries are provided, the first power relay device is connected to each of the multiple batteries, and the second power relay device changes the number of parallel connections of the multiple batteries. In this case, if a battery becomes unusable due to a malfunction or the like, the unusable battery can be disconnected. Also, for example, the second power relay device is provided in a position that is more outer than the first power relay device with respect to the center of the vehicle body. In this case, the second power relay device can be easily replaced. Furthermore, for example, the electric construction machine may have a cover that forms the exterior of the vehicle body, and the cover may be provided with an access opening for maintenance, and the second power relay device may be located closer to the access opening than the first power relay device. In this case, the second power relay device can be easily replaced using the access opening. Furthermore, for example, an insulation degradation sensor may be provided that monitors the insulation resistance between the vehicle body and the battery, and the insulation degradation sensor may be provided in the second power relay device. In this case, even in an electric construction machine that is used by increasing or decreasing the system output, any deterioration in circuit insulation can be easily detected.

[0008] According to the present invention, it is possible to provide an electric working machine that is capable of easily changing the system output.

[0009] 1A and 1B are diagrams illustrating an electric shovel according to the present embodiment. (a) and (b) are diagrams illustrating a first example of wiring between a high-voltage storage battery and a hub box, and wiring inside the hub box. (a) and (b) are diagrams illustrating a second example of wiring between a high-voltage storage battery and a hub box, and wiring inside the hub box. (a) is a diagram illustrating a third example of wiring between a high-voltage storage battery and a hub box, and wiring inside the hub box. (b) is a diagram illustrating a fourth example of wiring between a high-voltage storage battery and a hub box, and wiring inside the hub box. (a) is a diagram illustrating a fifth example of wiring between a high-voltage storage battery and a hub box, and wiring inside the hub box. (b) is a diagram illustrating a sixth example of wiring between a high-voltage storage battery and a hub box, and wiring inside the hub box. (a) to (c) are diagrams illustrating a seventh example of wiring between a high-voltage storage battery and a hub box, and wiring inside the hub box. Of these, (a) is the same as the diagram illustrated in FIG. 2A. (b) is a first example showing a case where the battery is disconnected. (c) is a second example showing a case where the battery is disconnected. (d) is a third example showing a case where the battery is disconnected. (a) to (d) are diagrams showing the position where a hub box is provided in an electric shovel. (a) and (b) are diagrams showing the position where an insulation deterioration sensor is to be disposed.

[0010] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0011] <Explanation of the configuration of the electric shovel 100> Fig. 1 is a diagram showing an electric shovel 100 according to this embodiment. The electric shovel 100 shown in Fig. 1 is an example of an electric work machine having a vehicle body. However, the electric work machine to which this embodiment is applied is not limited to the electric shovel 100, and may be a construction machine such as a wheel loader, a bulldozer, or a crane truck. The electric work machine may also be a truck that transports gravel or the like. Furthermore, for example, the electric work machine may be an agricultural machine such as a felling machine, a lumbering machine, a tractor, a forestry work vehicle, or a logging machine.

[0012] The electric shovel 100 shown in the figure is supplied with power from a system power supply 400 via a power cable 200. The electric shovel 100 is also supplied with power from a high-voltage storage battery 112. In other words, the electric shovel 100 is configured to be able to receive power from the system power supply 400 and also use power from a battery mounted on the electric shovel 100. However, in this embodiment, the power supplied to the electric shovel 100 may not be used, and the power may be supplied only from the high-voltage storage battery 112.

[0013] The electric shovel 100 includes a high-voltage circuit 110, a vehicle control device 120, a hydraulic circuit 130, and an operation system 140. The electric shovel 100 shown in the figure controls power supplied from a power cable 200 to the high-voltage circuit 110 using the vehicle control device 120 to drive an electric motor 118, which is a power source. The high-voltage circuit 110 includes an AC / DC converter 111 that receives power from a system power supply 400 and converts the AC power supplied from the power cable 200 into DC, a high-voltage storage battery 112 that is an example of a battery and stores power, an inverter 117 that is an example of an inverter device that converts the DC power from the AC / DC converter 111 and the high-voltage storage battery 112 into AC, an electric motor 118 that is driven by the AC power supplied from the inverter 117, and a hub box 150.

[0014] The hub box 150 relays the power from the high-voltage storage battery 112 and supplies it to the inverter 117. The detailed configuration of the hub box 150 will be described later.

[0015] The vehicle control device 120 changes the power received from the grid power supply 400 while the electric excavator 100 is in operation. The AC / DC converter 111 adjusts the power received from the grid power supply 400 (upper limit of received power). For example, the power received from the grid power supply 400 can be adjusted by adjusting the resistance value in a current limiting circuit of the AC / DC converter 111. The vehicle control device 120 includes a control and calculation function unit 121, a data recording unit (memory) 122, and a communication function unit 123. The control and calculation function unit 121 performs calculations to control the AC / DC converter 111, the high-voltage storage battery 112, and the inverter 117. The AC / DC converter 111, the high-voltage storage battery 112, and the inverter 117 are provided with control units (controllers) 111CO, 112CO, and 117CO, respectively. The control units 111CO, 112CO, and 117CO transmit data representing the states of the AC / DC converter 111, the high-voltage storage battery 112, and the inverter 117 to the control and calculation function unit 121. The control and calculation function unit 121 performs calculations based on the transmitted data and transmits control signals for controlling the AC / DC converter 111, the high-voltage storage battery 112, and the inverter 117 to the control units 111CO, 112CO, and 117CO. When adjusting the power received from the grid power supply 400, the vehicle control device 120 transmits a command, which is received by the control unit 111CO of the AC / DC converter 111. The setting of the AC / DC converter 111 is then changed, thereby changing the power received from the grid power supply 400. The data recording unit (memory) 122 records program data used by the control and calculation function unit 121 to perform calculations. The communication function unit 123 is a communication interface used when transmitting control signals to the control units 111CO, 112CO, and 117CO.

[0016] The hydraulic circuit 130 includes a hydraulic pump 131 that generates hydraulic pressure, a hydraulic oil tank 132 that stores hydraulic oil, a first directional control valve 133, and a second directional control valve 134. The hydraulic pump 131 is a variable displacement hydraulic pump that is driven by the electric motor 118. This hydraulic pump 131 draws hydraulic oil from the hydraulic oil tank 132 and supplies the hydraulic oil to the swing motor 14 and the work device hydraulic cylinder 16 of the electric excavator 100 via the first directional control valve 133 and the second directional control valve 134, thereby operating the electric excavator 100.

[0017] The operation system 140 is provided in the driver's cab of the electric shovel 100, and is used by the operator when operating the electric shovel 100. The operation system 140 includes a work mode selection switch, a motor control dial (not shown) for setting the rotation speed of the electric motor 118, operation levers 141A, 141B, etc. The operation levers 141A, 141B correspond to the respective swing motors 14 and working device hydraulic cylinders 16, and are, for example, electric levers that output an electric operation signal (lever signal Lv) corresponding to the amount of operation.

[0018] <Explanation of the Configuration of Hub Box 150> Next, the configuration of the hub box 150 will be described in detail. Figures 2(a) and 2(b) are diagrams showing a first example of the wiring between the high-voltage storage battery 112 and the hub box 150, and the wiring inside the hub box 150. In Figure 2(a), four batteries 112A to 112D are shown as the high-voltage storage battery 112 on the left side of the figure. Also shown from the center to the right side of the figure are hub boxes 151A11 and 151A12 of hub box (A) and hub box 152B1 of hub box (B) as the hub box 150.

[0019] Eight cables 153 are connected between the batteries 112A to 112D and the hub boxes 151A11 and 151A12. In this case, the eight cables 153 are connected using terminals 112T, two of which are provided on each of the batteries 112A to 112D, and connectors 151N, four of which are provided on one side (left side in the figure) of each of the hub boxes 151A11 and 151A12. In this case, the batteries 112A to 112D are connected to the cables 153 via the terminals 112T, but they may also be connected to the cables 153 via connectors (not shown) provided on the batteries 112A to 112D.

[0020] The hub boxes 151A11 and 151A12 are connected to the hub box 152B1 by four cables 154. In this case, the four cables 154 are connected using four connectors 151S provided on each of the other sides (right side in the figure) of the hub boxes 151A11 and 151A12 and four connectors 152N provided on each of one sides (left side in the figure) of the hub box 152B1.

[0021] Although not shown, a cable connected to the inverter 117 is connected to the right side of the hub box 152B1 in the drawing. This cable is connected using two connectors 152S provided on the other side (right side in the drawing) of the hub box 152B1.

[0022] In this configuration, power transmitted from batteries 112A to 112D is transmitted in this order via hub box 151A11 or hub box 151A12 and hub box 152B1, and then directed to inverter 117. Thus, hub box 150 serves as a power relay device that relays power from batteries 112A to 112D and supplies it to inverter 117.

[0023] The configuration of hub box 150 shown in Figure 2(a) can also be described as follows. Hub boxes 151A11 and 151A12 function as first power relay devices connected to batteries 112A-112D. Hub box 152B1 functions as a second power relay device connected to hub boxes 151A11 and 151A12, which are first power relay devices, and inverter 117. Connectors are provided at the output portions of hub boxes 151A11 and 151A12 to hub box 152B1, the input portions of hub box 152B1 from hub boxes 151A11 and 151A12, and the output portion of hub box 152B1 to inverter 117. These connectors are connector 151S, connector 152N, and connector 152S, respectively. Hub boxes 151A11, 151A12 are connected to hub box 152B1, and hub box 152B1 is connected to inverter 117 by cables via connectors. That is, hub boxes 151A11, 151A12 are connected to hub box 152B1 by cable 154 via connectors 151S, 152N. Hub box 152B1 is connected to inverter 117 by connector 152S and the cable connected to inverter 117, as described above. Batteries 112A-112D are connected to hub boxes 151A11, 151A12 by cable 153 via terminals or connectors provided on each battery. However, in FIG. 2A, the output portion of the batteries 112A to 112D to the hub boxes 151A11 and 151A12 is a terminal 112T, and the input portion of the hub boxes 151A11 and 151A12 from the batteries 112A to 112D is a connector 151N.

[0024] Compared to FIG. 2(a), FIG. 2(b) shows the case where hub box 152B1 has been replaced with hub box 152B2. Hub box 152B2 has the same number and location of connectors 152N as hub box 152B1, but the internal wiring is different. Hub boxes 152B1 and 152B2 are detachable, so hub box 152B1 can be replaced with hub box 152B2. Conversely, hub box 152B2 can also be replaced with hub box 152B1. In other words, among hub boxes 150, hub boxes 151A11 and 151A12 have fixed wiring, but hub boxes 152B1 and 152B2 can be swapped to have different wiring.

[0025] 2(a), the four batteries 112A to 112D can be wired in a two-in-series, two-in-parallel configuration. This allows the voltage of two batteries to be output from the hub box 150 to the inverter 117. On the other hand, in FIG. 2(b), the four batteries 112A to 112D can be wired in a four-in-series configuration (four in series, one in parallel). This allows the voltage of four batteries to be output from the hub box 150 to the inverter 117.

[0026] 2(a) and 2(b), the hub boxes 151A11 and 151A12 are connected to the multiple batteries 112A to 112D, respectively, and the hub boxes 152B1 and 152B2 change the series-parallel connection of the multiple batteries 112A to 112D. This configuration can also be described as changing the series-parallel connection of the batteries 112A to 112D by replacing the hub box 152B1 with one having a different wiring configuration. In this case, the hub boxes 151A11 and 151A12 combine the voltages required to operate the electric excavator 100. The hub boxes 151A11 and 151A12 are installed to obtain the voltage required to operate the electric excavator 100 at its rated output. The hub boxes 152B1 and 152B2 vary the voltage combined by the hub boxes 151A11 and 151A12. In other words, when the electric excavator 100 is operated at rated output during normal work, the wiring state using the hub box 152B1 shown in Fig. 2(a) is used. On the other hand, when work under a heavy load that cannot be handled by the rated output of the electric excavator 100 is required, the hub box 152B1 shown in Fig. 2(a) is replaced with the hub box 152B2, and the wiring state using the hub box 152B2 shown in Fig. 2(b) is used. This makes it possible to easily switch between operating the electric excavator 100 at normal rated output and operating it at a heavy load output that cannot be handled by the rated output, without changing the number of mounted batteries, by simply exchanging the hub box 152B1 and hub box 152B2, which serve as the second power relay device.

[0027] Furthermore, because hub boxes 151A11 and 151A12, which are the first power relay devices, and hub boxes 152B1 and 152B2, which are the second power relay devices, are connected by connectors 151S and 152N, cable 154 can be easily removed and reconnected. This simplifies the work of changing the wiring. In other words, because hub boxes 151A11 and 151A12, which are the first power relay devices, and hub boxes 152B1 and 152B2, which are the second power relay devices, are connected by connectors 151S and 152N, it is no longer necessary to open hub boxes 151A11 and 151A12 and hub boxes 152B1 and 152B2 or to use tools to change the terminal connections of cable 154, making it easy to remove and reconnect cable 154. Furthermore, when changing the system output, the operator only needs to disconnect and reconnect the cables 154 connected by connectors and replace the hub boxes 152B1 and 152B2, which are the second power relay devices, without touching the terminals 112T of the batteries 112A-112D. This prevents electric shock from the batteries 112A-112D. Furthermore, even if the hub box 152B1 is replaced with the hub box 152B2, the four cables 154 still use the same number and positions of connectors 151S and 152N. This prevents the cables 154 from being connected to the wrong connectors, ensuring excellent safety. The same applies to the cables connecting the hub boxes 152B1 and 152B2 to the inverter 117.

[0028] 3(a) and 3(b) are diagrams showing a second example of the wiring between the high-voltage storage battery 112 and the hub box 150, and the wiring inside the hub box 150. Comparing Figs. 3(a) and 3(b) with Figs. 2(a) and 2(b), Figs. 3(a) and 3(b) are similar except that the two hub boxes 151A11 and 151A12 are combined into one hub box 151A1.

[0029] FIG. 4( a) shows a third example of the wiring between the high-voltage battery 112 and the hub box 150, as well as the wiring inside the hub box 150. This third example is an electric excavator 100 with a higher normal rated output than that shown in FIG. 2( a). Comparing FIG. 4( a) with FIG. 2( a) reveals that the number of high-voltage batteries 112 has increased from four (batteries 112A-112D) to six (batteries 112A-112F). Correspondingly, the number of hub boxes 151A11-151A12 has increased from two (hub boxes 151A21-151A23) to three (hub boxes 151A21-151A23). Furthermore, the hub box 152B3 is wired in a two-in-series, three-in-parallel configuration for the six batteries 112A-112F. Furthermore, the number of cables 153 has increased from eight to twelve, and the number of cables 154 has increased from four to six.

[0030] FIG. 4(b) shows a fourth example of the wiring between the high-voltage battery 112 and the hub box 150, as well as the wiring inside the hub box 150. In this fourth example, the electric excavator 100 has a higher normal rated output than the third example. Comparing FIG. 4(b) with FIG. 2(a), the number of high-voltage batteries 112 has increased from four (batteries 112A-112D) to eight (batteries 112A-112F). Accordingly, the number of hub boxes 151A11-151A12 has increased from two (hub boxes 151A31-151A34) to four (hub boxes 151A31-151A34). Hub box 152B4 is wired two in series and four in parallel for the eight batteries 112A-112F. Furthermore, the number of cables 153 has increased from eight to sixteen, and the number of cables 154 has increased from four to eight.

[0031] In FIG. 4(a), the six batteries 112A-112F are wired in a 2-series, 3-parallel configuration. This allows the voltage equivalent to two batteries to be output from the hub box 150 to the inverter 117. Also, in FIG. 4(b), the eight batteries 112A-112H are wired in a 2-series, 4-parallel configuration. This allows the voltage equivalent to two batteries to be output from the hub box 150 to the inverter 117. Even in the cases of FIGS. 4(a) and 4(b), the series-parallel configuration of the batteries 112A-112D can be changed by replacing the hub box 152B3 or 152B4 with a different wiring configuration. In the case of FIG. 4(a), replacing the hub box 152B3 allows for a 6-series (6-series, 1-parallel) wiring configuration, for example. In the case of FIG. 4(b), replacing the hub box 152B4 allows for a 4-series, 2-parallel, or 8-series (8-series, 1-parallel) wiring configuration, for example.

[0032] FIG. 5(a) is a diagram showing a fifth example of the wiring between the high-voltage storage battery 112 and the hub box 150, and the wiring inside the hub box 150. The fifth example is similar to the third example, except that the three hub boxes 151A21-A23 are combined into one hub box 151A2. FIG. 5(b) is a diagram showing a sixth example of the wiring between the high-voltage storage battery 112 and the hub box 150, and the wiring inside the hub box 150. The sixth example is similar to the fourth example, except that the four hub boxes 151A31-A34 are combined into one hub box 151A3.

[0033] 6(a) to 6(c) are diagrams showing a seventh example of the wiring between the high-voltage storage battery 112 and the hub box 150, and the wiring inside the hub box 150. Of these, FIG. 6(a) is a diagram similar to the case shown in FIG. 2(a). Here, it is assumed that at least one of the batteries 112C and 112D has become inoperable due to a malfunction or the like. In this case, the battery 112C and the battery 112D are disconnected.

[0034] Figure 6(b) is a first example showing the case where battery 112C and battery 112D are disconnected. Here, the case where battery 112C and battery 112D are disconnected by removing the two lower cables 154 shown in Figure 6(a), resulting in a wiring configuration of two in series and one in parallel. These cables 154 are cables connected to hub box 151A12 and hub box 152B1 via connectors and are easily detachable.

[0035] FIG. 6C shows a second example in which batteries 112C and 112D are disconnected. Here, hub box 152B1 is replaced with hub box 152B5, disconnecting batteries 112C and 112D and changing the wiring from two in series and two in parallel to two in series and one in parallel. In this configuration, hub boxes 151A11 and 151A12 are connected to each of the multiple batteries 112A-112D, and hub boxes 152B1 and 152B5 change the number of parallel connections among the multiple batteries 112A-112D. In this configuration, replacing hub box 152B1 with one with a different wiring configuration changes the number of connected batteries 112A-112D. In this way, even when disconnecting an unusable battery due to a battery failure or the like, the work can be simplified by simply disconnecting and reconnecting the cable 154 connected by the connector and replacing the hub boxes 152B1 and 152B5, which are the second power relay devices. Furthermore, because the worker only needs to disconnect and reconnect the cable 154 connected by the connector and replace the hub boxes 152B1 and 152B5, which are the second power relay devices, there is no need for the worker to touch the terminals 112T of the batteries 112A to 112D. This prevents electric shock from the batteries 112A to 112D.

[0036] 7 shows a third example in which the batteries 112C and 112D are disconnected. In this case, a hub box 152B6 is used in which two disconnectors 152K are provided inside the hub box 152B1. By turning off the disconnectors 152K, the same wiring as the hub box 152B5 in FIG. 6C can be achieved. This allows the batteries 112C and 112D to be disconnected and the wiring to be two in series and one in parallel.

[0037] <Description of the Position Where the Hub Box 150 is Provided> FIGS. 8( a) to 8(d) and 9(a) and 9(b) are diagrams showing the position where the hub box 150 is provided in the electric shovel 100. In the diagrams, CAB is the driver's cab. LIB is a lithium-ion battery, which is the battery described above. Furthermore, C / W is a counterweight. In the diagrams, the X direction is the direction from the rear to the front of the body of the electric shovel 100. The Y direction is the direction from the right to the left of the body of the electric shovel 100. The Z direction is the direction from the bottom to the top of the body of the electric shovel 100. Of these, FIGS. 8(a) to 8(d) are diagrams showing the position where the hub box 150 is provided when the electric shovel 100 is viewed from above. Furthermore, FIGS. 9(a) and 9(b) are diagrams showing the position where the hub box 150 is provided when the electric shovel 100 is viewed from the side. Here, BOX_A refers to the hub boxes 151A1 to 151A3, 151A11 to 151A12, 151A21 to 151A23, and 151A31 to 151A34, which are the first power relay devices described above. Hereinafter, when there is no need to distinguish between the hub boxes 151A1 to 151A3, 151A11 to 151A12, 151A21 to 151A23, and 151A31 to 151A34, they may be simply referred to as hub boxes 151. Hereinafter, BOX_B refers to the hub boxes 152B1 to 152B6, which are the second power relay devices described above. Hereinafter, when there is no need to distinguish between the hub boxes 152B1 to 152B6, they may be simply referred to as hub boxes 152.

[0038] As shown in Figures 8 and 9, the hub box 152 is provided in a position that is more outward from the center O of the vehicle body than the hub box 151. The hub box 152 is also provided in proximity to an access opening 160 provided in the vehicle body. The electric shovel 100 has a cover that forms the exterior of the vehicle body, and the cover is provided with the access opening 160 as an opening for maintenance. The access opening 160 is fitted with a door, lid, or the like, and is closed by these in a normal state, but can be opened to access the inside of the electric shovel 100 during maintenance, etc. In other words, from the perspective of ease of attachment and detachment, the hub box 152 is preferably provided in a position that is more outward from the center O of the vehicle body than the hub box 151 and in a position that is closer to the access opening 160.

[0039] In the case of Figure 8(a), access opening 160 is provided in the center of the right side of the vehicle body, and hub box 152 is provided adjacent to access opening 160. Meanwhile, hub box 151 is provided further inward on the vehicle body than hub box 151, and hub box 152 is provided in a position that is more outward than hub box 151 with respect to the center O of the vehicle body. Furthermore, hub box 152 is provided in a position closer to access opening 160 than hub box 151.

[0040] In the case of Figure 8(b), the access opening 160 is provided in the front part of the right side of the vehicle body, and the hub box 152 is provided adjacent to the access opening 160. On the other hand, the hub box 151 is provided further rearward on the vehicle body than the hub box 152, and the hub box 152 is provided in a position that is more outward than the hub box 151 with respect to the center O of the vehicle body. In addition, the hub box 152 is provided in a position closer to the access opening 160 than the hub box 151.

[0041] In the case of Figure 8(c), access opening 160 is provided in the center of the left side of the vehicle body, and hub box 152 is provided adjacent to access opening 160. On the other hand, hub box 151 is provided in a position closer to the right side of the vehicle body than the left side, and hub box 152 is provided in a position that is more outward than hub box 151 with respect to the center O of the vehicle body. In addition, hub box 152 is provided in a position closer to access opening 160 than hub box 151.

[0042] In the case of Figure 8(d), access opening 160 is provided at the rear part of the right side of the vehicle body, and hub box 152 is provided adjacent to access opening 160. Meanwhile, hub box 151 is provided in a central position in the fore-and-aft direction of the vehicle body, and hub box 152 is provided in a position that is more outward than hub box 151 with respect to the center O of the vehicle body. Furthermore, hub box 152 is provided in a position closer to access opening 160 than hub box 151.

[0043] 9(a), access opening 160 is provided at the rear part of the upper surface of the vehicle body, and hub box 152 is provided adjacent to access opening 160. Meanwhile, hub box 151 is provided in a central position in the vertical direction of the vehicle body, and hub box 152 is provided in a position that is further outward than hub box 151 with respect to the center O of the vehicle body. Furthermore, hub box 152 is provided in a position closer to access opening 160 than hub box 151.

[0044] In the case of Figure 9(b), access opening 160 is provided at the rear part of the underside of the vehicle body, and hub box 152 is provided adjacent to access opening 160. Meanwhile, hub box 151 is provided in a central position in the vertical direction of the vehicle body, and hub box 152 is provided in a position that is more outward than hub box 151 with respect to the center O of the vehicle body. Furthermore, hub box 152 is provided in a position closer to access opening 160 than hub box 151.

[0045] <Description of Insulation Deterioration Sensor> The hub box 152 is preferably equipped with an insulation deterioration sensor. The insulation deterioration sensor is a sensor that monitors the insulation resistance between the vehicle body and the high-voltage storage battery 112, and has the function of outputting a warning signal if the insulation resistance deteriorates.

[0046] 10(a) and 10(b) are diagrams showing the position at which the insulation degradation sensor 152Z is ​​disposed. Of these, Fig. 10(a) shows an example in which the insulation degradation sensor 152Z is ​​attached to the hub box 152B1 shown in Fig. 2(a). Fig. 10(b) shows an example in which the insulation degradation sensor 152Z is ​​attached to the hub box 152B2 shown in Fig. 2(b). In both cases, the insulation degradation sensor 152Z is ​​provided so as to be connected to the transmission lines 152L1 and 152L2 supplied to the inverter 117.

[0047] As shown in these examples, it is preferable to provide the insulation degradation sensor 152Z in the hub box 152 rather than in the hub box 151. The specifications of the insulation degradation sensor 152Z must match the voltage to be used. That is, the insulation degradation sensor 152Z must match the voltage output to the inverter 117. In the case of FIG. 10(a), two batteries are connected in series and two batteries are connected in parallel, and the voltage used here is the voltage equivalent to two batteries output to the inverter 117, as described above. In the case of FIG. 10(b), four batteries are connected in series, and the voltage used here is the voltage equivalent to four batteries output to the inverter 117, as described above. The hub box 152 has a circuit configuration that changes this voltage. If an insulation degradation sensor 152Z that matches the voltage to be used is attached to the hub box 152, then when the hub box 152 is replaced, the appropriate insulation degradation sensor 152Z will automatically be attached. In this case, the insulation degradation sensor 152Z attached to the hub box 152B2 is selected to have a higher voltage specification than the insulation degradation sensor 152Z attached to the hub box 152B1. In Fig. 10(a), an insulation degradation sensor 152Z compatible with M (Middle) voltage is used, and in Fig. 10(b), an insulation degradation sensor 152Z compatible with Hi voltage is used as the higher voltage specification insulation degradation sensor 152Z.

[0048] Although the present embodiment has been described above, the technical scope of the present invention is not limited to the scope described in the above embodiment. It is clear from the claims that various modifications and improvements to the above embodiment are also included in the technical scope of the present invention.

[0049] DESCRIPTION OF SYMBOLS 100... electric shovel, 110... high voltage circuit, 111... AC / DC converter, 112... high voltage storage battery, 112A to 112H... battery, 112T... terminal, 151N, 151S, 152N, 152S... connector, 117... inverter, 120... vehicle control device, 151A1 to 151A3, 151A11 to 151A12, 151A21 to 151A23, 151A31 to 151A34... hub box (first power relay device), 152B1 to 152B6... hub box (second power relay device), 152Z... insulation deterioration sensor, 153, 154... cable, 160... access port

Claims

1. An electric working machine having a vehicle body, wherein the vehicle body includes a battery, an electric motor, and an inverter that supplies power from the battery to the electric motor, the electric working machine further comprising a first power relay device connected to the battery, and a second power relay device connected between the first power relay device and the inverter, wherein connectors are provided at an output portion of the first power relay device to the second power relay device, an input portion of the second power relay device from the first power relay device, and an output portion of the second power relay device to the inverter, and the connection between the first power relay device and the second power relay device and the connection between the second power relay device and the inverter are connected by a cable via the connectors.

2. The electric working machine according to claim 1, wherein the battery and the first power relay device are connected by a cable via terminals or connectors provided on each of them.

3. The electric working machine according to claim 2, wherein an output portion of the battery to the first power relay device is a terminal, and an input portion of the first power relay device from the battery is a connector.

4. The electric working machine according to claim 1, wherein a plurality of the batteries are provided, the first power relay device is connected to each of the plurality of batteries, and the second power relay device changes the series-parallel connection of the plurality of batteries.

5. The electric working machine according to claim 1, wherein a plurality of the batteries are provided, the first power relay device is connected to each of the plurality of batteries, and the second power relay device changes the number of parallel connections of the plurality of batteries.

6. The electric working machine according to claim 1, wherein the second power relay device is provided at a position outside the first power relay device with respect to the center of the vehicle body.

7. In the electric working machine according to claim 1, it has a cover that serves as the exterior of the vehicle body, an access port for maintenance is provided in the cover, and the second power relay device is provided at a position closer to the access port than the first power relay device. An electric working machine characterized by this.

8. In the electric working machine according to claim 1, it is provided with an insulation deterioration sensor that monitors the insulation resistance between the vehicle body and the battery, and the insulation deterioration sensor is provided in the second power relay device. An electric working machine characterized by this.

Images