Excavator

Abstract

This excavator includes: an upper rotating body having an electric power source; a lower traveling body having an actuator to which electric power is supplied from the electric power source and a driver for driving the actuator; and a slip ring for rotatably connecting the upper rotating body and the lower traveling body and electrically connecting the electric power source and the driver.

Description

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[0001] The present invention relates to an excavator. The present invention claims priority based on Japanese Patent Application No. 2024-167562 filed in Japan on September 26, 2024, and incorporates the content herein by reference.

[0002] Patent Document 1 discloses a technique in a hydraulic excavator in which a swivel joint is interposed at a position between an upper revolving body having a machine room and a lower traveling body having a lower frame. The swivel joint of Patent Document 1 is interposed in a fuel circuit to which an engine and a fuel tank are connected. Patent Document 1 does not disclose a technique related to a slip ring (equivalent to an electrical swivel joint).

[0003] Japanese Patent Application Laid-Open No. 2021-1567

[0004] In an excavator equipped with a slip ring, depending on the location of the driver that drives the actuator, the number of ports of the slip ring may increase. In this case, the number of wirings connected to the slip ring increases, and the structure of the excavator is likely to become complicated.

[0005] Therefore, an object of the present invention is to provide an excavator capable of simplifying the structure.

[0006] An excavator according to an aspect of the present invention includes an upper revolving body having a power source, an actuator supplied with power from the power source, a lower traveling body having a driver that drives the actuator, and a slip ring that rotatably connects the upper revolving body and the lower traveling body and electrically connects the power source and the driver.

[0007] According to the above aspect, the structure of the excavator can be simplified.

[0008] Left side view of the shovel according to the first embodiment. Perspective view of the shovel according to the first embodiment with the work implement removed, viewed from the upper right front. Block diagram of the electrical circuit of the shovel according to the first embodiment. Perspective view of the lower traveling body according to the first embodiment, viewed from the left rear. Perspective view of the center frame according to the first embodiment, viewed from the upper left rear. Bottom view showing the lower side outer plate of the center frame according to the first embodiment removed. Perspective view showing the arrangement of the driver according to the first embodiment. Diagram showing the arrangement of the driver according to a comparative example. Diagram showing the arrangement of the driver according to the first embodiment. Perspective view of the lower traveling body according to the second embodiment, viewed from the upper left, showing the internal structure of the left side. Perspective view of the lower traveling body according to the second embodiment, viewed from the lower left. Top view of the lower traveling body according to the second embodiment, showing the internal structure of the left side. Perspective view of the lower traveling body according to the third embodiment, viewed from the upper left, showing the internal structure of the left side. Perspective view of the lower traveling body according to the third embodiment, viewed from the lower left. Top view of the lower traveling body according to the third embodiment, showing the internal structure of the left side. A perspective view of the lower traveling body according to the fourth embodiment, viewed from the upper left, showing the internal structure of the left portion. A perspective view of the lower traveling body according to the fourth embodiment, viewed from the lower left. A top view of the lower traveling body according to the fourth embodiment, showing the internal structure of the left portion. A perspective view showing an example of a driver being placed within the side frame. A perspective view showing an example of a driver being placed within the connection part.

[0009] Embodiments of the present invention will be described below with reference to the drawings. In these embodiments, a fully electric power shovel will be described, in which the main power source and actuators (working equipment, travel motor, etc.) are electrically powered.

[0010] In the following explanation, expressions indicating relative or absolute arrangements, such as "parallel," "orthogonal," "centered," and "coaxial," mean not only strictly such arrangements or states, but also include arrangements or states that are relatively displaced by angles or distances that allow for tolerances or similar functions. In the drawings used in the following explanation, the scale of each component may be changed as appropriate to make each component recognizable.

[0011] <First Embodiment> Figure 1 is a left side view of the shovel 1 according to the first embodiment. Figure 2 is a perspective view of the shovel 1 according to the first embodiment with the work implement 10 removed, viewed from the upper right front. Figure 3 is a block diagram of the electrical circuit of the shovel 1 according to the first embodiment. In Figure 1, a part of the exterior of the shovel 1 is omitted. Referring together to Figures 1 to 3, the shovel 1 comprises an upper rotating body 2 having a battery 20 (power source), a lower traveling body 3 having actuators 35A, 35B, 35C to which power is supplied from the battery 20, and drivers 45A, 45B, 45C that drive the actuators 35A, 35B, 35C, and a slip ring 4 that rotatably connects the upper rotating body 2 and the lower traveling body 3 and electrically connects the battery 20 and the drivers 45A, 45B, 45C.

[0012] Hereinafter, the forward direction, reverse direction, and vehicle width direction of Shovel 1 will be referred to as "vehicle front (one side in the vehicle's front-rear direction)," "vehicle rear (the other side in the vehicle's front-rear direction)," and "vehicle width direction," respectively. The vehicle width direction may also be referred to as "left side (one side in the vehicle width direction)" or "right side (the other side in the vehicle width direction)." The right side is referred to as the right side with respect to the direction in which Shovel 1 moves forward, and the left side is referred to as the left side with respect to the direction in which Shovel 1 moves forward. The vertical direction, upward, and downward when Shovel 1 is positioned on a horizontal plane will simply be referred to as the "vertical direction," "upward," and "downward."

[0013] The upper slewing body 2 is rotatably mounted on the lower traveling body 3. The upper slewing body 2 is located on the upper part of the lower traveling body 3. The upper slewing body 2 is equipped with a battery 20 as a power source, a controller 21 (control unit), drivers (not shown) for the electric cylinders 14A, 14B, 14C, and 14D of the work machine 10, a DC-AC inverter 22 (for driving the motors of the electric cylinders 14A, 14B, 14C, and 14D), a slewing motor 23, and the like. The upper slewing body 2 is rotatable around the center of rotation (around the center of the slip ring 4) relative to the lower traveling body 3. The upper slewing body 2 rotates relative to the lower traveling body 3 when the slewing motor 23 is driven. The upper slewing body 2 has a controller 21 that controls the actuators 35A, 35B, and 35C.

[0014] For example, the operation method of the shovel 1 may be unmanned or manned. In the case of manned operation, a driver's cab may be provided in the upper rotating body 2. For example, the driver's cab may be equipped with a seat for the operator of the shovel 1, as well as levers, pedals, and instruments for various operations. The configuration of the driver's cab can be changed according to the design specifications.

[0015] A work implement 10 is connected to the upper slewing body 2. The work implement 10 is located at the front of the upper slewing body 2. The work implement 10 is mounted so as to be able to bend and raise relative to the upper slewing body 2. The work implement 10 (boom 11) is rotatable around an axis extending in the left-right direction relative to the upper slewing body 2, and is also oscillating (swinging) around an axis extending in the up-down direction.

[0016] The work machine 10 comprises a boom 11, an arm 12, a bucket 13 (working tool), and a plurality (for example, four) of electric cylinders 14A, 14B, 14C, and 14D. The four electric cylinders 14A, 14B, 14C, and 14D are a swing cylinder 14A that swings the boom 11, a boom cylinder 14B that operates the boom 11 (rotating it around an axis extending in the left-right direction), an arm cylinder 14C that operates the arm 12, and a bucket cylinder 14D that operates the bucket 13. The base end of the boom 11 is rotatably connected to the upper slewing body 2. The tip of the boom 11 is rotatably connected to the base end of the arm 12. The tip of the arm 12 is rotatably connected to the bucket 13.

[0017] The lower vehicle 3 is configured to be self-propelled. The lower vehicle 3 comprises a center frame 30, a pair of left and right tracks 31L and 31R, and actuators 35A and 35B (e.g., electric motors) that drive the tracks 31L and 31R. The lower vehicle 3 moves when the tracks 31L and 31R are driven by the left and right drive motors 35A and 35B.

[0018] A blade 32 is provided at the front of the lower traveling body 3. The blade 32 functions as a dozer blade extending in the vehicle width direction of the lower traveling body 3. The lower traveling body 3 is equipped with an actuator 35C (e.g., an electric motor) that drives the blade 32. The height position of the blade 32 may be adjustable by driving the actuator 35C (blade motor 35C).

[0019] The slip ring 4 is positioned between the upper rotating body 2 and the lower traveling body 3. The slip ring 4 extends vertically so as to penetrate both the upper rotating body 2 and the lower traveling body 3. Control signals and drive power are supplied from the upper rotating body 2 to the lower traveling body 3 via the slip ring 4. The slip ring 4 electrically connects the controller 21 and the drivers 45A, 45B, and 45C.

[0020] Power buses 40A and 40B extend from the upper rotating body 2 to the lower traveling body 3 via slip rings 4. One end of power buses 40A and 40B is connected to the battery 20 in the upper rotating body 2. Power buses 40A and 40B are connected to the drivers in the upper rotating body 2 and to the drivers 45A, 45B, and 45C included in the lower traveling body 3, respectively. With this configuration, drive power is supplied from the battery 20 in the upper rotating body 2 to the drivers 45A, 45B, and 45C in the lower traveling body 3 via slip rings 4. For example, another battery (e.g., a battery cell) or capacitor may be connected to the other end or in the middle (the portion between one end and the other end of power buses 40A and 40B). This makes it possible to reduce the size of the battery 20 in the upper rotating body 2.

[0021] The controller 21 is connected to each actuator via each driver using bus communication (communication lines 41), such as CAN (Controller Area Network) communication. With this configuration, the number of communication lines 41 can always be the same (for example, 4 lines in the case of CAN communication), regardless of the number of devices on the lower traveling body 3. For example, the controller 21 may be connected not only to one end of the communication line 41, but also to the other end or in the middle of the communication line 41 (the portion between one end and the other end of the communication line 41). The connection method of the controller 21 can be changed according to the design specifications.

[0022] The actuators in the upper slewing body 2 include electric cylinders 14A to 14D for the boom 11, arm 12, and bucket 13, and a slewing motor 23, etc. The actuators 35A, 35B, and 35C in the lower traveling body 3 consist of left and right traveling motors 35A and 35B and a motor 35C for the blade. Drivers 45A, 45B, and 45C are provided on the wiring that connects the slip ring 4 and the actuators 35A, 35B, and 35C in the lower traveling body 3.

[0023] Excavator 1 includes drivers 45A, 45B, and 45C that drive actuators 35A, 35B, and 35C, and a connector 46 that connects the drivers 45A, 45B, and 45C to the actuators 35A, 35B, and 35C. The drivers 45A, 45B, and 45C and the connector 46 are located on the lower traveling body 3.

[0024] The drivers 45A, 45B, and 45C are configured to include a left-hand drive driver 45A that controls the left-hand drive motor 35A in the left-right direction of the vehicle, a right-hand drive driver 45B that controls the right-hand drive motor 35B in the left-right direction of the vehicle, and a blade driver 45C that controls the blade 32.

[0025] Figure 4 is a perspective view of the lower traveling body 3 according to the first embodiment, viewed from the left rear. Figure 5 is a perspective view of the center frame 30 according to the first embodiment, viewed from the left rear upper. Figure 6 is a bottom view showing the center frame 30 according to the first embodiment with the outer plate on the lower side removed. Figure 7 is a perspective view showing the arrangement of drivers 45A, 45B, and 45C according to the first embodiment. Figures 4 to 6 omit illustrations of work equipment, etc. Referring together to Figures 4 to 7, the lower traveling body 3 comprises a center frame 30 that supports the slip ring 4, and side frames 33 that are located on both sides in the vehicle width direction relative to the center frame 30 and support the tracks 31L and 31R.

[0026] The drivers 45A, 45B, and 45C are located inside the center frame 30 or the side frame 33. For example, the internal space of the center frame 30 or the side frame 33 may be provided with wiring (not shown) connected to the slip ring 4, the drivers 45A, 45B, and 45C and / or the actuators 35A, 35B, and 35C.

[0027] The center frame 30 has a main body portion 60 that supports the slip ring 4 and a connecting portion 61 that connects the main body portion 60 and the side frame 33. The drivers 45A, 45B, and 45C are arranged inside the main body portion 60. The drivers 45A, 45B, and 45C are positioned in front of or behind the slip ring 4 in the longitudinal direction of the vehicle.

[0028] The center frame 30 is X-shaped in plan view. The connecting portion 61 includes a pair of legs 62L, 62R, 63L, and 63R that branch off from the main body 60 in the front-rear direction of the vehicle in plan view. The legs 62L, 62R, 63L, and 63R connect the left-right outer portion of the main body 60 to the left-right inner portion of the side frame 33. The front and rear pair of legs 62L, 62R, 63L, and 63R extend such that the distance between them in the front-rear direction increases as they move from the main body 60 toward the side frame 33 in plan view. Wiring (dashed lines shown in Figure 6) connected to the left and right travel motors 35A and 35B may be provided in the internal space of the rear pair of legs 63L and 63R.

[0029] A blade 32 (an example of a work implement) is connected to the front of the main body 60. Drivers 45A, 45B, and 45C are positioned behind the slip ring 4. A blade connection section 34 is provided at the front of the main body 60. An extension section 50 is provided at the rear of the main body 60. The extension section 50 is located on the opposite side from the blade connection section 34 in the vehicle's longitudinal direction.

[0030] The extension 50 is formed by extending the outer panels on the upper and side surfaces of the center frame 30 and includes a first wall portion 51 that covers the drivers 45A, 45B, and 45C from above in the vertical direction of the vehicle and from both sides in the left-right direction of the vehicle; a second wall portion 52 that is formed by extending the outer panel on the lower surface of the center frame 30 and covers the drivers 45A, 45B, and 45C from below in the vertical direction of the vehicle; and a third wall portion 53 that is connected to the first wall portion 51 and the second wall portion 52 and covers the drivers 45A, 45B, and 45C from the rear in the front-rear direction of the vehicle.

[0031] The extension 50 is formed by extending a part of the main body 60. The extension 50 is formed by joining together a first metal wall 51, which is formed by extending the outer plates on the upper and side sides of the main body 60, a second metal wall 52, which is formed by extending the outer plate on the lower side of the main body 60, and a third metal wall 53, by welding or the like.

[0032] For example, the thicknesses (plate thicknesses) of the first wall portion 51, the second wall portion 52, and the third wall portion 53 may be the same or different. If the thicknesses are different, for example, the thickness of the first wall portion 51 may be 10 mm or more and 14 mm or less. In this case, the thicknesses of the second wall portion 52 and the third wall portion 53 may be 6 mm or more and less than 10 mm. The thicknesses of the first wall portion 51, the second wall portion 52, and the third wall portion 53 are not limited to the above and can be changed according to the design specifications. In this embodiment, an example is described in which the extension portion 50 is formed by extending a part of the main body portion 60, but it is not limited to this.

[0033] Drivers 45A, 45B, and 45C are installed in a watertight manner in the lower traveling body 3. Watertight means that no liquid will flow into the interior under pressure. Drivers 45A, 45B, and 45C are installed in a watertight manner by being positioned inside the main body 60, which is formed by welding metal walls 51, 52, and 53 to each other, so as not to allow any liquid to flow into the main body 60.

[0034] For example, each driver 45A, 45B, 45C may be formed in a rectangular parallelepiped shape. The left and right driving drivers 45A, 45B may be arranged on the second wall portion 52. The blade driver 45C may be arranged on the right driving driver 45B. Space for optional equipment may be formed on the left driving driver 45A. For example, multiple drivers 45A, 45B, 45C may be arranged in a distributed manner. For example, at least one of the multiple drivers 45A, 45B, 45C may be arranged in a space within the side frame 33. The shape and / or arrangement of each driver 45A, 45B, 45C is not limited to the above and can be changed according to the design specifications.

[0035] Figure 8 shows the driver arrangement according to the comparative example. Figure 9 shows the driver arrangement according to the first embodiment. As shown in Figure 8, in the comparative example, the driver is located on the upper slewing body and the actuator is located on the lower traveling body, so the slip ring connects the driver on the upper slewing body and the actuator on the lower traveling body. For this reason, the number of ports and the number of wires connected to the slip ring in the comparative example are determined according to the number of components on which the driver is located on the upper slewing body and the actuator is located on the lower traveling body. As the number of components on which the driver is located on the upper slewing body and the actuator is located on the lower traveling body increases, the number of ports on the slip ring and the number of wires connected to the slip ring also increase. As a result, the excavator in the comparative example has a complex structure.

[0036] In contrast, in this embodiment, as shown in Figure 9, the driver and actuator are located on the lower travel body, so the slip ring in this embodiment does not need to connect the driver and actuator. Instead, the slip ring in this embodiment connects the battery located on the upper slewing body to one driver included in the lower travel body. Therefore, the slip ring in this embodiment can reduce the number of ports and the number of wires connected to the slip ring compared to the slip ring in the comparative example. As a result, the structure of the excavator can be simplified.

[0037] Furthermore, the slip ring of this embodiment does not depend on the number of ports or connected wires, nor on the number of drivers or actuators located on the lower travel body. Therefore, even if the number of drivers or actuators located on the lower travel body increases, the number of ports on the slip ring remains unchanged, as does the number of wires connected to the slip ring. As a result, the structure of the excavator can be simplified.

[0038] As described above, because the slip ring in this embodiment uses bus communication, the number of ports on the slip ring and the connected wiring do not change even if the number of drivers and actuators included in the lower vehicle increases. For example, even if the number of actuators in the lower vehicle increases due to optional additions, the same slip ring can be used.

[0039] In the example shown in Figure 8, the upper rotating body is equipped with left and right driving drivers and blade drivers. Power lines (DC) from the battery and communication lines (CAN, etc.) from the controller are connected to each driver. Power lines (AC) and signal lines (resolver, temperature) from each driver are connected via slip rings to each actuator (left and right driving motors and blade motor, indicated by M in the figure) on the lower traveling body. There is three-phase wiring between each driver and each motor, corresponding to the U phase, V phase, and W phase. In the example shown in Figure 9, the lower traveling body is equipped with left and right driving drivers and blade drivers. Power lines (DC) from the battery and communication lines (CAN, etc.) from the controller are connected via slip rings to each driver on the lower traveling body. Power lines (AC) and signal lines (resolver, temperature) from each driver are connected to each actuator (left and right driving motors and blade motor, indicated by M in the figure) on the lower traveling body. There is three-phase wiring between each driver and each motor, corresponding to the U phase, V phase, and W phase. The number of wires shown in Figures 8 and 9 is just an example and can be changed according to the design specifications.

[0040] <Effects and Effects> As described above, the excavator 1 of this embodiment comprises an upper rotating body 2 having a battery 20, a lower traveling body 3 having actuators 35A, 35B, 35C supplied with power from the battery 20 and drivers 45A, 45B, 45C that drive the actuators 35A, 35B, 35C, and a slip ring 4 that rotatably connects the upper rotating body 2 and the lower traveling body 3 and electrically connects the battery 20 and the drivers 45A, 45B, 45C. For example, as shown in Figure 8, if each driver is arranged on the upper rotating body, the number of ports on the slip ring may increase. In this case, the number of wires connected to the slip ring increases, and the structure of the excavator may become complex. In contrast, with this configuration, since each driver 45A, 45B, 45C is arranged on the lower traveling body 3, the number of wires connecting the slip ring 4 and the drivers 45A, 45B, 45C can be reduced. Therefore, the structure of the excavator 1 can be simplified.

[0041] In this embodiment, the upper swing body 2 has a controller 21 that controls the actuators 35A, 35B, and 35C. The slip ring 4 electrically connects the controller 21 and the drivers 45A, 45B, and 45C. According to this configuration, the controller 21 provided on the upper swing body 2 can control the actuators 35A, 35B, and 35C arranged on the lower traveling body 3 through the slip ring 4.

[0042] In this embodiment, the lower traveling body 3 includes a center frame 30 that supports the slip ring 4, and side frames 33 that are located on both sides in the vehicle width direction with respect to the center frame 30 and support the crawlers 31L and 31R. The drivers 45A, 45B, and 45C are arranged inside the center frame 30 or the side frames 33. According to this configuration, the drivers 45A, 45B, and 45C can be protected from external factors by being surrounded by the center frame 30 or the side frames 33. For example, the waterproofness and dustproofness of the drivers 45A, 45B, and 45C can be enhanced.

[0043] In this embodiment, the center frame 30 has a main body portion 60 that supports the slip ring 4. The drivers 45A, 45B, and 45C are arranged inside the main body portion 60. According to this configuration, the main body portion 60 of the center frame 30 can be used as an installation location for the drivers 45A, 45B, and 45C. For example, the unused cavities inside the main body portion 60 can be used to protect the drivers 45A, 45B, and 45C from external factors.

[0044] In this embodiment, the drivers 45A, 45B, and 45C are arranged in front of or behind the slip ring 4 in the vehicle longitudinal direction. According to this configuration, the front or rear of the slip ring 4 in the vehicle longitudinal direction can be used as an installation location for the drivers 45A, 45B, and 45C.

[0045] In this embodiment, a blade 32 is connected to the front portion of the main body 60. The drivers 45A, 45B, and 45C are arranged behind the slip ring 4. According to this configuration, since a wide space is easily secured behind the slip ring 4 because the blade 32 is not connected thereto, it is suitable for arranging the drivers 45A, 45B, and 45C.

[0046] In this embodiment, the drivers 45A, 45B, and 45C are installed in a watertight manner in the lower traveling body 3. According to this configuration, the waterproof property of the drivers 45A, 45B, and 45C can be enhanced.

[0047] In this embodiment, as shown in FIG. 7, the extension portion 50 is formed by extending the outer plates on the upper surface side and the side surface side of the center frame 30, and includes a first wall portion 51 that covers the drivers 45A, 45B, and 45C from above in the vehicle up-and-down direction and from both sides in the vehicle left-and-right direction, a second wall portion 52 that is formed by extending the outer plate on the lower surface side of the center frame 30 and covers the drivers 45A, 45B, and 45C from below in the vehicle up-and-down direction, and a third wall portion 53 that is connected to the first wall portion 51 and the second wall portion 52 and covers the drivers 45A, 45B, and 45C from the rear side in the vehicle front-and-rear direction. According to this configuration, the outer plates of the center frame 30 are extended in the front-and-rear direction to secure an installation space for the drivers 45A, 45B, and 45C, and the drivers 45A, 45B, and 45C can be protected from external factors.

[0048] In this embodiment, the drivers 45A, 45B, and 45C include a left traveling driver 45A that controls the traveling motor 35A on the left side in the vehicle left-and-right direction, a right traveling driver 45B that controls the traveling motor 35B on the right side in the vehicle left-and-right direction, and a blade driver 45C that controls the blade 32. According to this configuration, the number of wirings connecting the slip ring 4 and the respective drivers 45A, 45B, and 45C can be reduced. Therefore, the structure of the excavator 1 can be simplified.

[0049] <Second Embodiment> Figure 10 is a perspective view of the lower traveling body according to the second embodiment, viewed from the upper left, and shows the internal structure of the left portion. Figure 11 is a perspective view of the lower traveling body according to the second embodiment, viewed from the lower left. Figure 12 is a top view of the lower traveling body according to the second embodiment, and shows the internal structure of the left portion. Hereinafter, the excavator according to the second embodiment will be described with reference to Figures 10 to 12. In the configuration shown in Figures 10 to 12, the same reference numerals are used for components similar to those in the embodiment described above, and their detailed explanations are omitted.

[0050] The center frame 230 is composed of a main body 260 that supports the slip ring 4 and a connecting portion 261 that connects the main body 260 to the side frame 33. Inside the main body 260 or the connecting portion 261, there is space in which drivers 45A, 45B, and 45C can be arranged. For example, a battery cell or capacitor may be housed in the space inside the main body 260 or the connecting portion 261, or at least one of the drivers 45A, 45B, and 45C may be housed. This makes it possible to fill the space inside the main body 260 or the connecting portion 261 without waste.

[0051] The connecting portion 261 includes a pair of legs 262L, 262R, 263L, and 263R that branch off from the main body 260 in the front-rear direction of the vehicle when viewed from above. Inside the pair of legs 262L, 262R, 263L, and 263R, there is space for arranging drivers 45A, 45B, and 45C.

[0052] For example, the connecting portion 261 may include a front overhang 264 that extends forward along the outer edges of the front left and right pair of legs 262L, 262R, or it may include a rear overhang 265 that extends backward along the outer edges of the rear left and right pair of legs 263L, 263R. For example, the connecting portion 261 may include a left overhang 266L that extends to the left along the outer edges of the left front and rear pair of legs 262L, 263L, or it may include a right overhang 266R that extends to the right along the outer edges of the right front and rear pair of legs 262R, 263R. The configuration of the connecting portion 261 is not limited to the above and can be changed according to the design specifications.

[0053] For example, if there is ample space between a pair of legs 262L, 262R, 263L, and 263R, a battery cell or capacitor may be housed in the space between the pair of legs 262L, 262R, 263L, and 263R, or at least one of a plurality of drivers 45A, 45B, and 45C may be housed there. This allows for effective use of the space between the pair of legs 262L, 262R, 263L, and 263R.

[0054] For example, if there is unused space inside the side frame 33, battery cells or capacitors may be housed in the space inside the side frame 33, or at least one of the multiple drivers 45A, 45B, and 45C may be housed there. This makes it possible to fill the space inside the side frame 33 without wasting any space.

[0055] The center frame 230 has an opening 251h for inserting and removing drivers 45A, 45B, and 45C. The center frame 230 with the opening 251h is provided with a cover portion 252 to close the opening 251h.

[0056] The opening 251h is formed in the main body portion 260 of the center frame 230. The lid portion 252 is detachably attached to the main body portion 260. The main body portion 260 is composed of a bottom wall portion 251a formed in an annular shape in plan view, a peripheral wall portion 251b rising upward from the outer peripheral edge of the bottom wall portion 251a, and an upper wall portion 251c extending inward from the upper edge of the peripheral wall portion 251b and formed in an annular shape in plan view. The internal space of the main body portion 260 is the space enclosed by the bottom wall portion 251a, the peripheral wall portion 251b, the upper wall portion 251c, and the lid portion 252. For example, wiring (dashed lines in the figure) connected to the slip ring 4, drivers 45A, 45B, 45C and / or actuators 35A, 35B, 35C may be provided in the internal space of the main body portion 260. For example, the main body 260 may surround the drivers 45A, 45B, 45C, etc., with the upper surface of the bottom wall 251a, the inner surface of the peripheral wall 251b, the lower surface of the upper wall 251c, and the upper surface of the lid 252.

[0057] The main body 260 has a space inside which drivers 45A, 45B, and 45C can be placed. The opening 251h is formed by opening the bottom wall 251a of the main body 260 in the vertical direction. The opening 251h is circular in shape when viewed from above.

[0058] The lid portion 252 is detachably connected to the main body portion 260 via fastening members such as bolts. The lid portion 252 is formed in a circular shape with a size greater than or equal to the opening 251h when viewed from above. For example, with the lid portion 252 superimposed on the opening 251h when viewed from above, the lid portion 252 can be connected to the main body portion 260 by inserting a bolt through a through hole formed on the outer circumference of the lid portion 252 and screwing it into the female thread of a bracket provided on the bottom wall portion 251a of the main body portion 260.

[0059] The implement 10 is connected to the upper rotating body 2. The blade 32 (implement) is not connected to the center frame 230 of the lower traveling body 3. The center frame 230 does not have a blade connection section 34.

[0060] Drivers 45A, 45B, and 45C are installed in a watertight manner on the lower traveling body 3. Drivers 45A, 45B, and 45C are installed in a watertight manner so as not to allow liquid to flow into the main body 260, by being positioned inside the main body 260, which is surrounded by the bottom wall portion 251a, the peripheral wall portion 251b, the upper wall portion 251c, and the lid portion 252. For example, drivers 45A, 45B, and 45C may be installed in a watertight manner inside the main body 260 by fastening the lid portion 252 to the main body 260 with bolts via a rubber packing (an example of an elastic member).

[0061] In this embodiment, the center frame 230 has a main body portion 260 that supports the slip ring 4 and a connecting portion 261 that connects the main body portion 260 and the side frame 33. The drivers 45A, 45B, and 45C are arranged inside the main body portion 260 or the connecting portion 261. With this configuration, the main body portion 260 or the connecting portion 261 of the center frame 230 can be used as the installation location for the drivers 45A, 45B, and 45C. For example, the unused cavity inside the main body portion 260 or the connecting portion 261 can be used to protect the drivers 45A, 45B, and 45C from external factors.

[0062] In this embodiment, the drivers 45A, 45B, and 45C are arranged inside the side frame 33. With this configuration, the side frame 33 can be used as a mounting location for the drivers 45A, 45B, and 45C. For example, the unused cavity inside the side frame 33 can be used to protect the drivers 45A, 45B, and 45C from external factors.

[0063] In this embodiment, the center frame 230 has an opening 251h for inserting and removing drivers 45A, 45B, and 45C. The center frame 230 with the opening 251h is provided with a cover portion 252 that closes the opening 251h. With this configuration, when the opening 251h is closed by the cover portion 252, the drivers 45A, 45B, and 45C can be protected from external factors. On the other hand, when the cover portion 252 is removed and the opening 251h is open, the drivers 45A, 45B, and 45C can be inspected, etc.

[0064] In this embodiment, the drivers 45A, 45B, and 45C are installed in a watertight manner on the lower traveling body 3. This configuration enhances the waterproofness of the drivers 45A, 45B, and 45C.

[0065] In this embodiment, the work implement 10 is connected to the upper rotating body 2, and the blade 32 (work implement) is not connected to the center frame 230. The drivers 45A, 45B, and 45C are arranged inside the center frame 230 or the side frame 33. With this configuration, the center frame 230 or the side frame 33 can be used as the installation location for the drivers 45A, 45B, and 45C. The center frame 230 is suitable for arranging the drivers 45A, 45B, and 45C because it is easier to secure a large space since no work implement is connected to it.

[0066] <Third Embodiment> Figure 13 is a perspective view of the lower traveling body according to the third embodiment, viewed from the upper left, and shows the internal structure of the left portion. Figure 14 is a perspective view of the lower traveling body according to the third embodiment, viewed from the lower left. Figure 15 is a top view of the lower traveling body according to the third embodiment, and shows the internal structure of the left portion. Hereinafter, the excavator according to the third embodiment will be described with reference to Figures 13 to 15. In the configuration shown in the figures, the same reference numerals are used for components as in the embodiments described above, and their detailed descriptions are omitted.

[0067] The center frame 330 is composed of a main body 360 that supports the slip ring 4 and a connecting portion 361 that connects the main body 360 to the side frame 33. Inside the main body 360 or the connecting portion 361, there is space in which drivers 45A, 45B, and 45C can be arranged. For example, a battery cell or capacitor may be housed in the space inside the main body 360 or the connecting portion 361, or at least one of the drivers 45A, 45B, and 45C may be housed. This makes it possible to fill the space inside the main body 360 or the connecting portion 361 without waste.

[0068] For example, if there is unused space inside the side frame 33, battery cells or capacitors may be housed in the space inside the side frame 33, or at least one of the multiple drivers 45A, 45B, and 45C may be housed there. This makes it possible to fill the space inside the side frame 33 without wasting any space.

[0069] The center frame 330 has an opening 351h for inserting and removing drivers 45A, 45B, and 45C. The center frame 330 with the opening 351h is provided with a cover portion 352 to close the opening 351h.

[0070] The opening 351h is formed in the main body portion 360 of the center frame 330. The lid portion 352 is detachably provided with respect to the main body portion 360. The main body portion 360 is composed of a bottom wall portion 351a, which in plan view has an outer edge formed in the shape of an octagonal frame, a side wall portion 351b that rises upward from the outer edge of the bottom wall portion 351a, and an upper wall portion 351c that is provided above the side wall portion 351b and is formed in the shape of an annular ring in plan view. The internal space of the main body portion 360 is the space enclosed by the bottom wall portion 351a, the side wall portion 351b, the upper wall portion 351c, and the lid portion 352. For example, wiring (dashed lines in the figure) connected to the slip ring 4, drivers 45A, 45B, 45C and / or actuators 35A, 35B, 35C may be provided in the internal space of the main body portion 360. For example, the main body 360 may surround the drivers 45A, 45B, 45C, etc., with the upper surface of the bottom wall 351a, the inner circumferential surface of the side wall 351b, the lower surface of the upper wall 351c, and the upper surface of the lid 352.

[0071] The main body 360 has a space inside which drivers 45A, 45B, and 45C can be placed. The opening 351h is formed by opening the bottom wall 351a of the main body 360 in the vertical direction. The opening 351h is circular in shape when viewed from above.

[0072] The lid portion 352 is detachably connected to the main body portion 360 via fastening members such as bolts. The lid portion 352 is formed in a rectangular shape with a size greater than or equal to the opening 351h when viewed from above. For example, with the lid portion 352 superimposed on the opening 351h when viewed from above, the lid portion 352 can be connected to the main body portion 360 by inserting bolts through through holes formed in each corner (each corner) of the lid portion 352 and screwing them into nuts provided on the bottom wall portion 351a of the main body portion 360.

[0073] Drivers 45A, 45B, and 45C are installed in a watertight manner on the lower traveling body 3. Drivers 45A, 45B, and 45C are installed in a watertight manner so as not to allow liquid to flow into the main body 360, by being positioned inside the main body 360, which is surrounded by the bottom wall portion 351a, the side wall portion 351b, the top wall portion 351c, and the lid portion 352. For example, drivers 45A, 45B, and 45C may be installed in a watertight manner inside the main body 360 by fastening the lid portion 352 to the main body 360 with bolts via a rubber packing (an example of an elastic member).

[0074] In this embodiment, the center frame 330 has a main body portion 360 that supports the slip ring 4 and a connecting portion 361 that connects the main body portion 360 and the side frame 33. The drivers 45A, 45B, and 45C are arranged inside the main body portion 360 or the connecting portion 361. With this configuration, the main body portion 360 or the connecting portion 361 of the center frame 330 can be used as the installation location for the drivers 45A, 45B, and 45C. For example, the drivers 45A, 45B, and 45C can be protected from external factors by utilizing the unused cavity inside the main body portion 360 or the connecting portion 361.

[0075] In this embodiment, the drivers 45A, 45B, and 45C are arranged inside the side frame 33. With this configuration, the side frame 33 can be used as a mounting location for the drivers 45A, 45B, and 45C. For example, the unused cavity inside the side frame 33 can be used to protect the drivers 45A, 45B, and 45C from external factors.

[0076] In this embodiment, the center frame 330 has an opening 351h for inserting and removing drivers 45A, 45B, and 45C. The center frame 330 with the opening 351h is provided with a cover portion 352 that closes the opening 351h. With this configuration, when the opening 351h is closed by the cover portion 352, the drivers 45A, 45B, and 45C can be protected from external factors. On the other hand, when the cover portion 352 is removed and the opening 351h is open, the drivers 45A, 45B, and 45C can be inspected, etc.

[0077] In this embodiment, the drivers 45A, 45B, and 45C are installed in a watertight manner on the lower traveling body 3. This configuration enhances the waterproofness of the drivers 45A, 45B, and 45C.

[0078] <Fourth Embodiment> Figure 16 is a perspective view of the lower traveling body according to the fourth embodiment, viewed from the upper left, and shows the internal structure of the left portion. Figure 17 is a perspective view of the lower traveling body according to the fourth embodiment, viewed from the lower left. Figure 18 is a top view of the lower traveling body according to the fourth embodiment, and shows the internal structure of the left portion. Hereinafter, the excavator according to the fourth embodiment will be described with reference to Figures 16 to 18. In the configuration shown in the figures, the same reference numerals are used for components as in the embodiments described above, and their detailed descriptions are omitted.

[0079] The center frame 430 is composed of a main body 460 that supports the slip ring 4 and a connecting portion 461 that connects the main body 460 to the side frame 33. Inside the main body 460 or the connecting portion 461, there is space in which drivers 45A, 45B, and 45C can be arranged. For example, a battery cell or capacitor may be housed in the space inside the main body 460 or the connecting portion 461, or at least one of the drivers 45A, 45B, and 45C may be housed. This makes it possible to fill the space inside the main body 460 or the connecting portion 461 without waste.

[0080] The connecting portion 461 includes a pair of legs 462L, 462R, 463L, and 463R that branch off from the main body 460 in the front-rear direction of the vehicle when viewed from above. Inside the pair of legs 462L, 462R, 463L, and 463R, there is space for arranging drivers 45A, 45B, and 45C.

[0081] For example, the connecting portion 461 may include a front overhang 464 that extends forward along the outer edges of the front left and right pair of legs 462L, 462R, or it may include a rear overhang 465 that extends backward along the outer edges of the rear left and right pair of legs 463L, 463R. For example, the connecting portion 461 may include a left overhang 466L that extends to the left along the outer edges of the left front and rear pair of legs 462L, 463L, or it may include a right overhang 466R that extends to the right along the outer edges of the right front and rear pair of legs 462R, 463R. The configuration of the connecting portion 461 is not limited to the above and can be changed according to the design specifications.

[0082] For example, if there is ample space between a pair of legs 462L, 462R, 463L, and 463R, a battery cell or capacitor may be housed in the space between the pair of legs 462L, 462R, 463L, and 463R, or at least one of a plurality of drivers 45A, 45B, and 45C may be housed in the space between the pair of legs 462L, 462R, 463L, and 463R. This allows for effective use of the space between the pair of legs 462L, 462R, 463L, and 463R.

[0083] For example, if there is unused space inside the side frame 33, battery cells or capacitors may be housed in the space inside the side frame 33, or at least one of the multiple drivers 45A, 45B, and 45C may be housed there. This makes it possible to fill the space inside the side frame 33 without wasting any space.

[0084] The center frame 430 has an opening 451h for inserting and removing drivers 45A, 45B, and 45C. The center frame 430 with the opening 451h is provided with a cover portion 452 to close the opening 451h.

[0085] The opening 451h is formed in the main body portion 460 of the center frame 430. The lid portion 452 is detachably attached to the main body portion 460. The main body portion 460 is composed of a bottom wall portion 451a formed in an annular shape in plan view, a peripheral wall portion 451b rising upward from the outer peripheral edge of the bottom wall portion 451a, and an upper wall portion 451c extending inward from the upper edge of the peripheral wall portion 451b and formed in an annular shape in plan view. The internal space of the main body portion 460 is the space enclosed by the bottom wall portion 451a, the peripheral wall portion 451b, the upper wall portion 451c, and the lid portion 452. For example, wiring (dashed lines in the figure) connected to the slip ring 4, drivers 45A, 45B, 45C and / or actuators 35A, 35B, 35C may be provided in the internal space of the main body portion 460. For example, the main body 460 may surround the drivers 45A, 45B, 45C, etc., with the upper surface of the bottom wall 451a, the inner surface of the peripheral wall 451b, the lower surface of the upper wall 451c, and the upper surface of the lid 452.

[0086] The main body 460 has a space inside which drivers 45A, 45B, and 45C can be placed. The opening 451h is formed by opening the bottom wall 451a of the main body 460 in the vertical direction. In plan view, the opening 451h is circular (in the example shown, it is an elongated oval or ellipse in the horizontal direction).

[0087] The lid portion 452 is detachably connected to the main body portion 460 via fastening members such as bolts. The lid portion 452 is formed in a circular shape (an elongated oval or elliptical shape in the example shown) that is larger than or equal to the opening 451h when viewed from above. For example, with the lid portion 452 superimposed on the opening 451h in a view from above, the lid portion 452 can be connected to the main body portion 460 by inserting a bolt through a through hole formed on the outer circumference of the lid portion 452 and screwing it into the female thread of a bracket provided on the bottom wall portion 451a of the main body portion 460.

[0088] Drivers 45A, 45B, and 45C are installed in a watertight manner on the lower traveling body 3. Drivers 45A, 45B, and 45C are installed in a watertight manner so as not to allow liquid to flow into the main body 460, by being positioned inside the main body 460, which is surrounded by the bottom wall portion 451a, the peripheral wall portion 451b, the upper wall portion 451c, and the lid portion 452. For example, drivers 45A, 45B, and 45C may be installed in a watertight manner inside the main body 460 by fastening the lid portion 452 to the main body 460 with bolts via a rubber packing (an example of an elastic member).

[0089] In this embodiment, the center frame 430 has a main body portion 460 that supports the slip ring 4 and a connecting portion 461 that connects the main body portion 460 and the side frame 33. The drivers 45A, 45B, and 45C are arranged inside the main body portion 460 or the connecting portion 461. With this configuration, the main body portion 460 or the connecting portion 461 of the center frame 430 can be used as the installation location for the drivers 45A, 45B, and 45C. For example, the drivers 45A, 45B, and 45C can be protected from external factors by utilizing the unused cavity inside the main body portion 460 or the connecting portion 461.

[0090] In this embodiment, the drivers 45A, 45B, and 45C are arranged inside the side frame 33. With this configuration, the side frame 33 can be used as a mounting location for the drivers 45A, 45B, and 45C. For example, the unused cavity inside the side frame 33 can be used to protect the drivers 45A, 45B, and 45C from external factors.

[0091] In this embodiment, the center frame 430 has an opening 451h for inserting and removing drivers 45A, 45B, and 45C. The center frame 430 with the opening 451h is provided with a cover 452 that closes the opening 451h. With this configuration, when the opening 451h is closed by the cover 452, the drivers 45A, 45B, and 45C can be protected from external factors. On the other hand, when the cover 452 is removed and the opening 251h is open, the drivers 45A, 45B, and 45C can be inspected, etc.

[0092] In this embodiment, the drivers 45A, 45B, and 45C are installed in a watertight manner on the lower traveling body 3. This configuration enhances the waterproofness of the drivers 45A, 45B, and 45C.

[0093] <Modification> In the above-described embodiment, the upper slewing body has a control unit for controlling the actuator, and the slip ring is described as electrically connecting the control unit and the driver, but the invention is not limited to this. For example, the control unit for controlling the actuator may be provided on the lower traveling body. For example, the upper slewing body does not have to have a control unit for controlling the actuator. The installation configuration of the control unit can be changed according to the design specifications.

[0094] In the embodiments described above, the lower running gear comprises a center frame that supports the slip rings and side frames that are located on both sides in the vehicle width direction relative to the center frame and support the tracks, and the driver is described as being located inside the center frame or side frame, but it is not limited to this. For example, the driver may be located in a different place in the lower running gear from the center frame and side frames. The manner in which the driver is installed in the lower running gear can be changed according to the design specifications.

[0095] In the embodiments described above, the center frame has a main body that supports the slip rings, and the driver is described as being located inside the main body; however, it is not limited to this. For example, the driver may be located outside the main body. The configuration of the driver on the center frame can be changed according to the design specifications.

[0096] In the embodiments described above, the driver was described as being positioned in front of or behind the slip ring in the longitudinal direction of the vehicle, but it is not limited to this. For example, the driver may be positioned to the left or right of the slip ring in the vehicle width direction. The configuration of the driver relative to the slip ring can be changed according to the design specifications.

[0097] In the embodiments described above, the work implement is connected to the front of the main body, and the driver is positioned behind the slip ring. However, the invention is not limited to this configuration. For example, the driver may be positioned to the left or right of the slip ring. The configuration of the driver relative to the connection point of the work implement can be changed according to the design specifications.

[0098] In the embodiments described above, the center frame has a main body that supports the slip ring and a connecting portion that connects the main body and the side frame, and the driver is described as being located inside the connecting portion, but it is not limited to this. For example, the driver may be located inside the main body or the side frame. For example, the driver may be located in a different location on the center frame from the connecting portion. The configuration of the driver on the center frame can be changed according to the design specifications.

[0099] In the embodiments described above, the center frame was explained as being X-shaped in plan view, but it is not limited to this. For example, the center frame may be I-shaped in plan view. The plan view shape of the center frame is not limited to the above and can be changed according to the design specifications.

[0100] In the embodiments described above, the driver was described as being located inside the side frame, but this is not limited to this. For example, the driver may be located in a different location from the side frame in the lower travel body. The installation method of the driver in the lower travel body can be changed according to the design specifications.

[0101] In the embodiments described above, an example was given in which the center frame has an opening for inserting and removing a screwdriver, and the center frame with the opening is provided with a cover to close the opening, but the invention is not limited to this. For example, the side frame may have an opening for inserting and removing a screwdriver, and the side frame with the opening may be provided with a cover to close the opening. For example, the manner in which the opening is formed and / or the manner in which the cover is installed can be changed according to the design specifications.

[0102] In the embodiments described above, the driver was explained as being installed in a watertight manner on the lower traveling body, but this is not limited to this. For example, the driver may be installed outside the lower traveling body. For example, the driver does not have to be installed in a watertight manner on the lower traveling body. The manner in which the driver is installed on the lower traveling body can be changed according to the design specifications.

[0103] As shown in Figure 19, each of the drivers 45A, 45B, and 45C may be placed inside the side frame 33. With this configuration, each of the drivers 45A, 45B, and 45C is enclosed by the side frame 33, thereby protecting each of the drivers 45A, 45B, and 45C from external factors.

[0104] As shown in Figure 20, each of the drivers 45A, 45B, and 45C may be placed inside the connecting portion 61 (leg portion 62L in the example shown) that connects the main body portion 60 and the side frame 33. With this configuration, each of the drivers 45A, 45B, and 45C is surrounded by the connecting portion 61 (leg portion 62L in the example shown), thereby protecting each of the drivers 45A, 45B, and 45C from external factors.

[0105] In the embodiments described above, an example of a fully electric power shovel, in which the main power source and actuators (work implements, travel motors, etc.) are electrically powered, was given, but the invention is not limited to this. For example, the shovel may be equipped with hydraulic motors instead of some electric motors. For example, the shovel may have an electric main power source and the actuators (work implements, travel motors, etc.) may be operated by hydraulics. The configuration of the shovel is not limited to the above and can be changed according to the design specifications.

[0106] Although embodiments of the present invention have been described above, the present invention is not limited thereto, and additions, omissions, substitutions, and other modifications to the configuration are possible without departing from the spirit of the invention, and the above embodiments can be combined as appropriate.

[0107] (Note 1) An excavator comprising: an upper rotating body having a power source; a lower traveling body having an actuator supplied with power from the power source and a driver for driving the actuator; and a slip ring that rotatably connects the upper rotating body and the lower traveling body and electrically connects the power source and the driver. (Note 2) The excavator according to Note 1, wherein the upper rotating body has a control unit for controlling the actuator, and the slip ring electrically connects the control unit and the driver. (Note 3) The excavator according to Note 2, wherein the lower traveling body comprises a center frame supporting the slip ring and side frames located on both sides in the vehicle width direction relative to the center frame and supporting the tracks, and the driver is disposed inside the center frame or the side frames. (Note 4) The excavator according to Note 3, wherein the center frame has a main body that supports the slip ring, and the driver is disposed inside the main body. (Note 5) The excavator according to Note 4, wherein the driver is positioned in front of or behind the slip ring in the longitudinal direction of the vehicle. (Note 6) The excavator according to Note 5, wherein a work implement is connected to the front of the main body, and the driver is positioned behind the slip ring. (Note 7) The excavator according to any one of Notes 3 to 6, wherein the center frame has a main body that supports the slip ring and a connecting part that connects the main body and the side frame, and the driver is positioned inside the connecting part. (Note 8) The excavator according to Note 7, wherein the center frame is X-shaped in plan view. (Note 9) The excavator according to any one of Notes 3 to 8, wherein the driver is positioned inside the side frame. (Note 10) The center frame or the side frame has an opening for inserting and removing the driver, and the center frame or the side frame having the opening is provided with a cover for closing the opening, as described in any of Notes 3 to 9. (Note 11) The driver is installed in a watertight manner on the lower traveling body, as described in any of Notes 1 to 10.

[0108] 1...Shovel, 2...Upper rotating body, 3...Lower running body, 4...Slip ring, 10...Work implement, 20...Battery (power source), 21...Controller (control unit), 30, 230, 330, 430...Center frame, 31L, 31R...Tracks, 32...Blade (work implement), 33...Side frame, 35A, 35B, 35C...Actuators, 45A...Left running driver (driver), 45B...Right running driver (driver), 45C...Blade driver (driver), 60, 260, 360, 460...Main body, 61, 261, 361, 461...Connection part, 251h, 351h, 451h...Opening, 252, 352, 452...Lid part,

Claims

1. An excavator comprising: an upper rotating body having a power source; a lower traveling body having an actuator supplied with power from the power source and a driver for driving the actuator; and a slip ring that rotatably connects the upper rotating body and the lower traveling body and electrically connects the power source and the driver.

2. The excavator according to claim 1, wherein the upper rotating body has a control unit for controlling the actuator, and the slip ring electrically connects the control unit and the driver.

3. The excavator according to claim 2, wherein the lower running body comprises a center frame that supports the slip ring and side frames that are located on both sides in the vehicle width direction relative to the center frame and support the tracks, and the driver is positioned inside the center frame or the side frames.

4. The shovel according to claim 3, wherein the center frame has a main body portion that supports the slip ring, and the driver is disposed inside the main body portion.

5. The shovel according to claim 4, wherein the driver is positioned in front of or behind the slip ring in the longitudinal direction of the vehicle.

6. The excavator according to claim 5, wherein a work implement is connected to the front of the main body, and the driver is positioned behind the slip ring.

7. The shovel according to claim 3, wherein the center frame has a main body portion that supports the slip ring and a connecting portion that connects the main body portion and the side frame, and the driver is disposed inside the connecting portion.

8. The excavator according to claim 7, wherein the center frame is X-shaped in plan view.

9. The shovel according to claim 3, wherein the driver is located inside the side frame.

10. The shovel according to claim 3, wherein the center frame or the side frame has an opening for inserting and removing the driver, and the center frame or the side frame having the opening is provided with a cover for closing the opening.

11. The shovel according to any one of claims 1 to 10, wherein the driver is installed in a watertight manner on the lower traveling body.

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