Electric construction machine

Abstract

To provide an electric construction machine capable of mounting many hydrogen storage devices.SOLUTION: A hydraulic excavator has a vehicle body made up of a lower traveling body 3B and an upper rotating body that is rotatably mounted on the lower traveling body 3B. A position of a center of gravity G of a hydrogen storage device provided on the vehicle body is, in plan view, contained within a frame (rectangular area 312) defined by both front-to-rear end portions (front tipping fulcrum P1 and rear tipping fulcrum P2) of ground contact areas (ground contact portions) 310, 311 of the lower traveling body 3B and both left-to-right end portions (left lateral tipping fulcrum P3 and right lateral tipping fulcrum P4) of the ground contact areas 310, 311 of the lower traveling body 3B, regardless of the state of rotation of the upper rotating body relative to the lower traveling body 3B.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to an electric construction machine. [Background technology]

[0002] For electric construction machinery powered by fuel cells, there is a demand to carry more hydrogen as an energy source in order to increase operating time. However, because the size of the vehicle body is limited, the size of the hydrogen storage device that can be installed is naturally also limited. As a method for solving this problem, Patent Document 1 discloses a configuration in which a hydrogen storage alloy is housed within a counterweight, so that the weight of the hydrogen storage alloy also serves as the weight of the counterweight. With this configuration, there is no need to install a hydrogen storage device and a counterweight separately, which also solves the problem of installation space restrictions. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2003-213728 Summary of the Invention [Problem to be solved by the invention]

[0004] However, depending on the model of electric construction machine and its posture when turning, the center of gravity of the counterweight may be located outside the tipping fulcrum of the vehicle body. Therefore, when considering the weight balance with the working device installed in the front of the electric construction machine, there is a problem that the amount of hydrogen storage device that can be installed is limited even when a configuration is adopted in which the hydrogen storage alloy is housed inside the counterweight.

[0005] An object of the present invention is to provide an electric construction machine that can be equipped with many hydrogen storage devices. [Means for solving the problem]

[0006] An electric construction machine according to one aspect of the present invention has a vehicle body consisting of a lower running body and an upper rotating body that is rotatably mounted on the lower running body, and the vehicle body is equipped with an electric motor that serves as a power source, a fuel cell that supplies power to the electric motor, and a hydrogen storage device that stores hydrogen that is supplied to the fuel cell, and the hydrogen storage device is arranged on the vehicle body so that its center of gravity fits within a frame defined by both front-to-rear ends of the ground contact portion of the lower running body and both left-to-right ends of the ground contact portion of the lower running body in a plan view, regardless of the rotation state of the upper rotating body relative to the lower running body. [Effects of the Invention]

[0007] According to the present invention, many hydrogen storage devices can be mounted on an electric construction machine. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a diagram showing the appearance of a hydraulic excavator. [Figure 2] FIG. 2 is a diagram illustrating the tipping support of the hydraulic excavator. [Figure 3] FIG. 3 is a diagram illustrating the arrangement of the devices provided on the upper rotating body. [Figure 4] FIG. 4 is a diagram showing a state in which the upper rotating body has rotated 90 degrees to the left relative to the lower traveling body from the state shown in FIG. [Figure 5] FIG. 5 is a perspective view of a lower traveling body in the second embodiment. [Figure 6] FIG. 6 is a view taken along the arrow D in FIG. [Figure 7] FIG. 7 is a perspective view of a lower traveling body in a modified example. [Figure 8] FIG. 8 is an exploded perspective view of a fixing member according to a modified example. [Figure 9] FIG. 9 is a diagram illustrating the attachment of the hydrogen storage device to the fixing member. [Figure 10] FIG. 10 is a plan view of a lower traveling body in the third embodiment. [Figure 11]FIG. 11 is a cross-sectional view taken along the line E-E in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. The following description and drawings are examples for explaining the present invention, and appropriate omissions and simplifications have been made for clarity of explanation. Furthermore, in the following description, identical or similar elements and processes are given the same reference numerals, and duplicate explanations may be omitted. Note that the content described below merely shows an example of an embodiment of the present invention, and the present invention is not limited to the following embodiment, and can be implemented in various other forms.

[0010] First Embodiment Fig. 1 is a diagram showing the appearance of a hydraulic excavator 1. The hydraulic excavator 1 comprises a self-propelled lower traveling body 3B, an upper rotating body 3A rotatably attached to the lower traveling body 3B, and a front attachment 4 attached to the upper rotating body 3A. Fig. 1 is a diagram of the hydraulic excavator 1 as seen from the left side, and the left-right direction in the figure is the fore-and-aft direction of the hydraulic excavator 1, and the direction perpendicular to the plane of the page is the left-right direction of the hydraulic excavator 1.

[0011] The upper rotating body 3A is mounted on the lower traveling body 3B via a rotating device 5. The lower traveling body 3B has crawlers 31a and 31b on both the left and right sides, each of which is driven by a traveling motor 30. In FIG. 1, the right crawler 31b is hidden and not visible. When the hydraulic excavator 1 is upright without tilting relative to the ground 10, the crawlers 31a and 31b of the lower traveling body 3B are in contact with the ground 10.

[0012] 2 is a diagram illustrating the tipping fulcrum of the hydraulic excavator 1, and shows the lower traveling body 3B and the crawlers 31a, 31b in a plan view of the lower traveling body 3B seen from above. The hatched areas 310, 311 of each crawler 31a, 31b represent the portion of the crawler 31a, 31b facing the ground 10 when the lower traveling body 3B is upright without tilting relative to the ground 10. Here, the hatched areas 310, 311 are referred to as ground contact areas. The ground contact areas 310, 311 are areas that are set in advance based on the dimensions of the crawlers 31a, 31b of the lower traveling body 3B and are determined for each model.

[0013] The tipping fulcrum is a point that serves as a fulcrum when a construction machine such as a hydraulic excavator tips over. When the hydraulic excavator 1 tips forward in FIG. 1, the lower traveling body 3B of the hydraulic excavator 1 tilts with the front ends P1 of the ground contact areas 310, 311 of the crawlers 31a, 31b in FIG. 2 as the fulcrum. Conversely, when the hydraulic excavator 1 tips backward, the lower traveling body 3B tilts with the rear ends P2 of the ground contact areas 310, 311 as the fulcrum. Similarly, when the hydraulic excavator 1 tips over to the left, the left ends P3 of the ground contact areas 310, 311 (i.e., the left end of the left ground contact area 310) serve as the fulcrum, and when the hydraulic excavator 1 tips over to the right, the right ends P4 of the ground contact areas 310, 311 (i.e., the right end of the right ground contact area 311) serve as the fulcrum. Hereinafter, the fulcrums P1 to P4 will be referred to as a forward tipping fulcrum P1, a backward tipping fulcrum P2, a left side tipping fulcrum P3, and a right side tipping fulcrum P4, respectively.

[0014] 3 and 4 are diagrams illustrating the arrangement of equipment provided on the upper rotating body 3A of the hydraulic excavator 1. Fig. 3 shows a case where the upper rotating body 3A is rotated such that the front attachment 4 is in front of the lower traveling body 3B. On the other hand, Fig. 4 shows a state where the upper rotating body 3A has rotated 90 degrees to the left of the lower traveling body 3B from the state shown in Fig. 3.

[0015] A cab 12, various hydraulic equipment, an electric motor 13, various components constituting the power supply, a cooling system, a counterweight 14, and the like are mounted on a main frame 11 of the upper rotating body 3A. The hydraulic equipment includes a hydraulic pump 15 that is driven by the electric motor 13 and generates pressurized oil, a hydraulic oil tank 16, and a hydraulic valve 17 that controls the flow of pressurized oil. The power source for the electric motor 13 is made up of a fuel cell (FC) module 18 and a hydrogen storage device 19, among other components. Note that the symbol G indicates the center of gravity of the hydrogen storage device 19. The cooling system is made up of a heat exchanger 20, a cooling fan 21, and the like. The cab 12, in which the operator sits, is provided at the front of the main frame 11, and the counterweight 14 is mounted at the rear end of the main frame 11.

[0016] The center of gravity of the counterweight 14 is located further rearward than the rear tipping fulcrum P2 in the swing state shown in FIG. 3, and is located to the right of the right side tipping fulcrum P4 in the swing state shown in FIG. 4. Here, x and y coordinate axes are set as shown in FIG. 2, and the x and y coordinates of the tipping fulcrums P1 to P4 and the center of gravity of the counterweight 14 are (x(P1), y(P1)), (x(P2), y(P2)), (x(P3), y(P3)), (x(P4), y(P4)), and (x(P14), y(P14)). The center of gravity of the counterweight 14 satisfies y(P2) > y(P14) in the case of FIG. 3, and x(P14) > x(P4) in the case of FIG. 4. That is, the x and y coordinates of the center of gravity of the counterweight 14 are located outside a rectangular area (area indicated by a dashed line) 312 enclosed by the lines indicating the tipping fulcrums P1 to P4.

[0017] On the other hand, in Figure 2, the xy position of the center of gravity G of the hydrogen storage device 19 in the swing state shown in Figure 3 is the position indicated by the black circle. Because the hydrogen storage device 19 is mounted on the upper swing body 3A, it changes depending on the swing state of the upper swing body 3A. In Figure 2, symbol C1 indicates the swing center of the upper swing body 3A. The center of gravity G of the hydrogen storage device 19 moves on a circumference 190 centered on the swing center C1 depending on the swing state of the upper swing body 3A. In other words, regardless of the swing state of the upper swing body 3A, the center of gravity G of the hydrogen storage device 19 will be located between the front tipping fulcrum P1 and the rear tipping fulcrum P2 and between the left side tipping fulcrum P3 and the right side tipping fulcrum P4 in a plan view.

[0018] By arranging the hydrogen storage device 19 between the tipping fulcrums of the lower traveling body 3B when mounting it on the upper rotating body 3A in this way, the hydraulic excavator 1 will not tip over even if the weight of the hydrogen storage device 19 exceeds the balance weight of the front attachment 4. In other words, tipping of the hydraulic excavator 1 due to the weight of the hydrogen storage device 19 can be prevented, and more hydrogen storage devices 19 can be mounted without being subject to weight restrictions. On the other hand, in a configuration in which the hydrogen storage device (hydrogen storage alloy) 19 is housed within the counterweight 14 as described in Patent Document 1, the counterweight 14 is located outside the rectangular area 312 surrounded by the lines indicating the tipping fulcrums P1 to P4 in a plan view. Therefore, if the weight of the hydrogen storage device (hydrogen storage alloy) 19 becomes excessive, there is a risk of the excavator tipping over on the side where the counterweight 14 is provided.

[0019] <Second embodiment> 5 and 6 are diagrams illustrating a second embodiment of the present invention. In the first embodiment described above, the hydrogen storage device 19 was mounted on the upper rotating body 3A, but in the second embodiment, it is mounted on the lower traveling body 3B. FIG. 5 is a perspective view of the lower traveling body 3B on which the rotating device 5 is provided. The rotating device 5 is provided in the center of the track frame 32 of the lower traveling body 3B, and travel motors 30 are provided at the rear ends of both the left and right sides of the track frame 32. Four hydrogen storage devices 19 are attached to the track frame 32 by fixing members 6, respectively.

[0020] The fixing member 6 is composed of a bracket 6a attached to the truck frame 32 and a metal band 6b that fixes the hydrogen storage device 19 to the bracket 6a. Each hydrogen storage device 19 is positioned inward of the crawlers 31a, 31b in the left-right direction of the vehicle. In the example shown in Figure 5, the hydrogen storage device 19 is detachably fixed to the bracket 6a attached to the truck frame 32 by the band 6b, but it may also be fixed directly to the truck frame 32 by the band 6b.

[0021] In the case of a configuration in which the hydrogen storage device 19 is disposed inside the exterior cover of the main frame 11 as in the first embodiment, the installation space may be limited due to its relationship with other equipment. On the other hand, in the second embodiment, by utilizing the free space on the truck frame 32, it is possible to mount more hydrogen storage devices 19. Of course, the hydrogen storage devices 19 may be mounted on both the main frame 11 and the truck frame 32.

[0022] 6 is a view taken along arrow D in FIG. 5, showing the lower traveling body 3B as seen from the left side of the vehicle. The hydrogen storage devices 19 are arranged so that the position of their center of gravity G is between the front tipping fulcrum P1 and the rear tipping fulcrum P2. Each hydrogen storage device 19 is arranged more inward than the crawlers 31a, 31b in the left-right direction of the vehicle. Therefore, the left-right position of the center of gravity G of each hydrogen storage device 19 in a plan view is located between the tipping fulcrums P3, P4, which are the outer ends of the ground contact areas 310, 311 of the crawlers 31a, 31b. As a result, as in the first embodiment, even if the weight of the hydrogen storage device 19 increases, tipping of the hydraulic excavator 1 due to the weight of the hydrogen storage device 19 can be prevented.

[0023] (Variation) 7 to 9 are diagrams illustrating a modified example of the second embodiment described above. FIG. 7 is a perspective view of a lower traveling body 3B in the modified example. In the modified example, the structure of the fixing member 6 differs from that of the second embodiment described above. FIG. 8 is an exploded perspective view of the fixing member 6 in the modified example. The fixing member 6 in the modified example is composed of a bracket 6c attached to the truck frame 32, and two sets of a first clamping member 6d and a second clamping member 6e for fixing the hydrogen storage device 19 to the bracket 6c.

[0024] The bracket 6c has a fixing portion 60 fixed to the truck frame 32 with a bolt 62, and an upright portion 61 extending upright from the fixing portion 60. The pair of first clamping members 6d are fixed to both longitudinal ends of the upright portion 61 with bolts 63. The pair of second clamping members 6e are each fixed to the first clamping member 6d with a bolt 64. As shown in FIG. 9 , small-diameter supported portions 190 are provided on both ends of the cylindrical hydrogen storage device 19. The hydrogen storage device 19 is fixed to the upright portion 61 of the bracket 6c by clamping the supported portions 190 on both ends between the first clamping member 6d and the second clamping member 6e, respectively.

[0025] <Third embodiment> 10 and 11 are diagrams illustrating a third embodiment of the present invention. In the second embodiment, a hydrogen storage device 19 made of a hydrogen storage alloy is stored in a hollow region 320 in a truck frame 32. FIG. 10 is a plan view of a lower traveling body 3B. FIG. 11 is an E-E cross-sectional view of FIG. 10. A turning device 5 is provided in the center of the X-shaped truck frame 32. As shown in FIG. 11, hollow regions 320 having a rectangular cross section are formed in four frames extending obliquely from the center of the truck frame 32. A hydrogen storage device 19 is disposed in each hollow region 320.

[0026] Storing the hydrogen storage devices 19 in hollow area 320 within truck frame 32 in this way prevents the adverse effects of external environmental factors such as dust and moisture. Furthermore, the center of gravity G of each hydrogen storage device 19 is located between front tipping fulcrum P1 and rear tipping fulcrum P2 and between left side tipping fulcrum P3 and right side tipping fulcrum P4, as shown in Figure 10, so tipping due to the weight of the hydrogen storage devices 19 can be prevented.

[0027] In the first to third embodiments described above, the hydraulic excavator 1 that travels on crawlers has been described as an example of an electric construction machine, but the present invention is not limited to hydraulic excavators and can be applied to various electric construction machines. For example, the present invention can also be applied to wheel loaders that travel on tires, in which case the contact point of the tires is set as the tipping fulcrum.

[0028] According to the embodiment and modified examples of the present invention described above, the following advantageous effects are achieved.

[0029] (1) As shown in Figures 2 and 3, a hydraulic excavator 1, which is an electric construction machine, has a vehicle body 3 consisting of a lower traveling body 3B and an upper rotating body 3A that is rotatably mounted on the lower traveling body 3B. The vehicle body 3 is equipped with an electric motor 13 as a power source, an FC module (fuel cell) 18 that supplies power to the electric motor 13, and a hydrogen storage device 19 that stores hydrogen that is supplied to the FC module 18. In a plan view, the center of gravity of the hydrogen storage device 19 is located within a frame (rectangular area 312) that is defined by both front-to-rear end portions (front tipping fulcrum P1 and rear tipping fulcrum P2) of the ground contact areas (ground contact portions) 310, 311 of the lower traveling body 3B and both left-to-right end portions (left lateral tipping fulcrum P3 and right lateral tipping fulcrum P4) of the ground contact areas 310, 311 of the lower traveling body 3B, regardless of the rotation state of the upper rotating body 3A relative to the lower traveling body 3B.

[0030] As described above, the center of gravity of the hydrogen storage device 19 is located between the front tipping fulcrum P1 and the rear tipping fulcrum P2 in a plan view, and between the left side tipping fulcrum P3 and the right side tipping fulcrum P4, which prevents the hydraulic excavator 1 from tipping over due to the weight of the hydrogen storage device 19. This allows a larger number of hydrogen storage devices 19 to be mounted while preventing tipping over.

[0031] (2) In the above (1), the hydrogen storage device 19 may be provided on the upper rotating body 3A as shown in Figures 3 and 4. This makes it possible to prevent the hydraulic excavator 1 from tipping over due to the weight of the hydrogen storage device 19, regardless of the rotation state of the upper rotating body 3A.

[0032] (3) In the above (1), the hydrogen storage device 19 may be disposed on the lower running body 3B as shown in Figures 5, 7 to 11, etc. For example, in the examples shown in Figures 5 and 7, the hydrogen storage device 19 is disposed on the track frame 32 of the lower running body 3B. In this way, by utilizing the empty space on the track frame 32, it becomes possible to mount more hydrogen storage devices 19.

[0033] In the configuration shown in Figure 5, the hydrogen storage device 19 is detachably fixed to the bracket 6a on the truck frame 32 by a band 6d, which is an elastically deformable band-shaped member, and in the configurations shown in Figures 7 to 9, the hydrogen storage device 19 is detachably fixed to the bracket 6c by first and second clamping members 6d, 6e. This makes it easy to replace the hydrogen storage device 19.

[0034] 10 and 11, the track frame 32 provided on the lower traveling body 3B may have a hollow area 320 therein, and the hydrogen storage device 19 made of a hydrogen storage alloy may be housed in the hollow area 320. By housing the hydrogen storage device 19 in the hollow area 320, it is possible to prevent adverse effects of the external environment, such as dust and moisture, and to suppress deterioration of the hydrogen storage alloy.

[0035] The above-described embodiments and various modified examples are merely examples, and the present invention is not limited to these contents as long as the characteristics of the invention are not impaired. Other aspects that can be considered within the technical scope of the present invention are also included within the scope of the present invention. [Explanation of symbols]

[0036] 1...hydraulic excavator (electric construction machine), 3...vehicle body, 3A...upper rotating body, 3B...lower running body (running body), 4...front attachment, 5...swivel device, 6...fixing member, 6a, 6c...bracket, 6b...band (strip-shaped member), 6d...first clamping member, 6e...second clamping member, 11...main frame, 12...cab, 13...electric motor, 14...counterweight, 15...hydraulic pump, 1 8...FC module (fuel cell), 19...hydrogen storage device, 31a, 31b...crawler, 32...track frame, 310, 311...ground contact area (ground contact portion), 312...rectangular area (frame), 320...hollow area, G...center of gravity, P1...forward tipping fulcrum (front end), P2...rear tipping fulcrum (rear end), P3...left side tipping fulcrum (left end), P4...right side tipping fulcrum (right end)

Claims

1. The vehicle has a vehicle body including a lower traveling body and an upper rotating body rotatably provided on the lower traveling body, In an electric construction machine, the vehicle body includes an electric motor as a power source, a fuel cell that supplies power to the electric motor, and a hydrogen storage device that stores hydrogen to be supplied to the fuel cell, An electric construction machine characterized in that the hydrogen storage device is arranged on the body so that its center of gravity fits within a frame defined by both front-to-rear ends of the ground contact portion of the lower running body and both left-to-right ends of the ground contact portion of the lower running body in a plan view, regardless of the rotation state of the upper rotating body relative to the lower running body.

2. The electric construction machine according to claim 1, The electric construction machine is characterized in that the hydrogen storage device is provided on the upper rotating body.

3. The electric construction machine according to claim 1, The hydrogen storage device is disposed on the undercarriage of the electric construction machine.

4. The electric construction machine according to claim 3, The hydrogen storage device is detachably fixed to brackets provided on both sides of the lower traveling body in the left and right direction.

5. The electric construction machine according to claim 3, The hydrogen storage device is detachably fixed to the undercarriage by an elastically deformable band-shaped member.

6. The electric construction machine according to claim 3, the undercarriage has an internal hollow area; The hydrogen storage device is made of a hydrogen absorbing alloy and is housed in the hollow area.

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