Work machine

Abstract

Provided is a work machine (1) in which a hydrogen tank can be mounted. A work machine (1) comprises a lower traveling body (10), an upper turning body (20) mounted on the lower traveling body (10) so as to be capable of turning, a work device (30) capable of performing a work operation that is a relative operation with respect to the upper turning body (20), a motive power source (41) for generating motive power by using hydrogen as a fuel, and a hydrogen supply system (HS) for supplying hydrogen to the motive power source (41). The motive power source (41) is mounted on the upper turning body (20). The hydrogen supply system (HS) includes a hydrogen tank (50) for storing hydrogen, and the hydrogen tank (50) is mounted on the work device (30).

Description

Work machinery

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

[0002] Patent Document 1 discloses a work machine having an upper rotating body including a counterweight and an energy storage system including a fuel cell, at least a portion of the energy storage system being installed as part of the counterweight.

[0003] When the fuel cell is a hydrogen fuel cell, the energy source is hydrogen, and therefore the working machine needs to be equipped with a hydrogen tank for storing hydrogen.

[0004] JP 2014-9589 A

[0005] An object of the present invention is to provide a work machine that can be equipped with a hydrogen tank.

[0006] The present invention provides a working machine comprising: a lower traveling body, an upper rotating body mounted on the lower traveling body so as to be rotatable relative to the lower traveling body, a working device connected to the upper rotating body and capable of performing a working operation that is a relative operation with respect to the upper rotating body, a power source mounted on the upper rotating body and generating power using hydrogen as fuel, and a hydrogen supply system that supplies hydrogen to the power source. The hydrogen supply system includes a hydrogen tank that stores hydrogen, and the hydrogen tank is mounted on the working device.

[0007] FIG. 1 is a side view of a work machine according to a first embodiment of the present invention, with a tank cover and a fill port cover removed from a work device of the work machine. FIG. 2 is a side view of the work machine according to the first embodiment, with the tank cover and the fill port cover attached to the work device. FIG. 3 is a rear view of the body of the work machine according to the first embodiment. FIG. 4 is a block diagram showing a drive system of the work machine according to the first embodiment. FIG. 5 is a perspective view showing a boom of a work machine according to a second embodiment of the present invention. FIG. 6 is a side view of a work machine according to a third embodiment of the present invention.

[0008] Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0009] Figures 1 to 3 show a work machine 1 according to a first embodiment of the present invention. The work machine 1 illustrated in Figures 1 to 3 is a crawler-type shovel. However, the work machine according to the present invention is not limited to shovels. Examples of work machines other than shovels include demolition machines, loading and unloading machines, and agricultural machines.

[0010] The work machine 1 includes a lower traveling body 10, an upper rotating body 20, a working device 30, a drive system 40 shown in Fig. 4, and a hydrogen supply system HS. The lower traveling body 10 and the upper rotating body 20 constitute the body of the work machine.

[0011] The lower traveling body 10 is capable of traveling on the ground. The lower traveling body 10 illustrated in FIG. 3 includes a traveling frame 11 that supports the upper rotating body 20 and a pair of traveling devices 12.

[0012] As shown in Figure 2, the travel frame 11 includes a central frame 11A and a pair of crawler frames 11B. The upper rotating body 20 is connected to the central frame 11A. The pair of crawler frames 11B are disposed on both sides of the central frame 11A in the width direction of the lower travel structure. The width direction of the lower travel structure is a direction perpendicular to the fore-aft direction of the lower travel structure, and the fore-aft direction of the lower travel structure is a direction parallel to the travel direction in which the lower travel structure 10 travels. The pair of crawler frames 11B are integrally connected to both ends of the central frame 11A in the width direction of the lower travel structure, i.e., the left and right ends.

[0013] The pair of travelling devices 12 operate to enable the undercarriage 10 to travel on the ground. The pair of travelling devices 12 illustrated in FIGS. 1 to 3 are so-called crawler-type devices and are supported by the pair of crawler frames 11B, respectively. Each of the pair of travelling devices 12 includes a front idler, a sprocket, an upper roller, a lower roller, and a crawler. The front idler is located in front of the crawler frame 11B in the longitudinal direction of the undercarriage. The sprocket is located behind the crawler frame 11B in the longitudinal direction of the undercarriage. The upper roller is located above the crawler frame 11B and between the front idler and the sprocket in the longitudinal direction of the undercarriage. The lower roller is located below the crawler frame 11B and between the front idler and the sprocket in the longitudinal direction of the undercarriage. The crawler is stretched around the front idler, the sprocket, the upper roller, and the lower roller.

[0014] As shown in FIGS. 1 to 3 , the upper rotating body 20 includes a revolving frame 24, a cab 21, and a machinery room 22. The revolving frame 24 is disposed on the undercarriage 10 and is connected to the undercarriage 10, specifically the central frame 11A, so as to be revolvable about an axis longitudinal to the undercarriage 10, i.e., the central axis of revolving shown in FIG. 4 . The cab 21 is mounted on the front of the revolving frame 24 in the fore-and-aft direction of the upper rotating body. The cab 21 includes a driver's seat and an operating unit (not shown), and an operator seated in the driver's seat can operate the operating unit to move the work machine 1. The fore-and-aft direction of the upper rotating body is the fore-and-aft direction as seen from the operator seated in the driver's seat. The machinery room 22 is mounted on the rear of the revolving frame 24 and houses a part of the drive system 40.

[0015] The working device 30 is connected to the upper rotating body 20 so as to be able to perform a work operation. The work operation is a relative movement with respect to the upper rotating body 20 for performing work.

[0016] The working device 30 includes a boom 31 , an arm 32 , and a tip attachment 33 .

[0017] The boom 31 is arranged on the revolving frame 24 so as to be aligned with the operator's cab 21 in the width direction of the upper revolving structure. The width direction of the upper revolving structure is a direction perpendicular to the fore-and-aft direction of the upper revolving structure and the revolving central axis. The boom 31 has a boom base end and a boom tip end. The boom base end is rotatably connected to the upper revolving structure 20 so that the boom 31 can perform a hoisting operation. The boom tip end is the end opposite the boom base end. The hoisting operation is an operation in which the boom 31 rotates relative to the upper revolving structure 20 so that the boom tip moves up and down.

[0018] The arm 32 has an arm base end and an arm tip end on the opposite side thereof. The arm base end is connected to the boom tip end so that the arm 32 can rotate up and down relative to the boom 31.

[0019] The tip attachment 33 constitutes the tip of the working device 30. The tip attachment 33 is connected to the tip of the arm 32 so as to be rotatable in the up and down direction relative to the arm 32. The tip attachment 33 illustrated in Figure 1 is a bucket. The working operation is constituted by at least one of the raising and lowering operation of the boom 31, the rotation of the arm 32, and the rotation of the tip attachment 33.

[0020] A group of work actuators 44B for moving the boom 31, the arm 32, and the tip attachment 33 are attached to the working device 30. The group of work actuators 44B are included in the drive system 40. As shown in FIG. 1 , the group of work actuators 44B includes a boom cylinder 46, an arm cylinder 47, and a tip attachment cylinder 48, each of which is an extendable and retractable hydraulic cylinder. The boom cylinder 46 extends and retracts to cause the boom 31 to perform the raising and lowering operation relative to the upper rotating body 20. The arm cylinder 47 extends and retracts to cause the arm 32 to perform the rotation operation relative to the boom 31. The tip attachment cylinder 48 extends and retracts to cause the tip attachment 33 to perform the rotation operation relative to the arm 32.

[0021] The drive system 40 is a system that hydraulically drives each of a plurality of movable parts of the work machine 1. As shown in Figure 4, the drive system 40 includes a power source 41, a working pump 42, a control valve unit 43, an actuator group 44 consisting of a plurality of actuators, and a hydraulic oil tank 45, and the power source 41, the working pump 42, the control valve unit 43 and the hydraulic oil tank 45 are housed in the machine room 22.

[0022] The power source 41 generates power for driving the working pump 42. The power source 41 according to the first embodiment is configured to generate electricity using hydrogen as fuel and drive the working pump 42 with the generated electricity. As shown in FIG. 3 , the power source 41 includes a hydrogen fuel cell 41A and an electric motor 41B. The hydrogen fuel cell 41A generates electricity by reacting hydrogen, supplied as fuel by the hydrogen supply system HS, with oxygen in the air. The electric motor 41B is driven by the electricity generated by the hydrogen fuel cell 41A and thereby drives the working pump 42. Specifically, the electric motor 41B has an output shaft that is rotated by the electricity, and the output shaft is connected to the rotary shaft of the working pump 42. Therefore, the working pump 42 is driven by driving the electric motor 41B, i.e., by rotating the output shaft.

[0023] A preferred example of the electric motor 41B is a three-phase motor including an inverter. The inverter performs current control to control the rotation of the output shaft. Specifically, the inverter converts the direct current supplied from the hydrogen fuel cell 41A into three-phase alternating current, and the output shaft of the electric motor 41B is rotated by the three-phase alternating current.

[0024] The power source 41 may further include a secondary battery (a so-called battery).

[0025] Various modifications can be made to the specific configuration of the power source 41. For example, the power source 41 may include a hydrogen engine instead of the hydrogen fuel cell 41A and the electric motor 41B, and the hydrogen engine is an internal combustion engine that directly generates power by burning hydrogen.

[0026] The working pump 42 is a hydraulic pump, and is driven by the power source 41 to supply working oil from the working oil tank 45 to the plurality of actuators in the actuator group 44 through the control valve unit 43 .

[0027] The control valve unit 43 includes a plurality of control valves, each of which corresponds to a respective one of the actuators included in the actuator group 44. Each of the control valves opens and closes in accordance with an operation given to the operating unit by an operator in the cab 21 so as to control the supply of hydraulic oil to the actuator and the return of hydraulic oil from the actuator.

[0028] The plurality of actuators in the actuator group 44 operate to move a plurality of movable parts of the work machine 1 by the supply of hydraulic oil controlled by the control valve. Specifically, the plurality of actuators include a swing motor 44A, the work actuator group 44B, and a pair of travel motors 44C.

[0029] The swing motor 44A is a hydraulic motor for swinging the upper swing body 20 relative to the lower traveling body 10. As described above, the work actuator group 44B includes the boom cylinder 46, the arm cylinder 47, and the tip attachment cylinder 48. The pair of travel motors 44C are hydraulic motors for driving the pair of traveling devices 12, and are connected to the sprockets to rotate the sprockets.

[0030] The hydrogen supply system HS supplies hydrogen as fuel to the power source 41. Specifically, the hydrogen supply system HS includes a hydrogen tank 50, a hydrogen receiving section 51, a pressure reducing valve 52, a tank cover 54, a fill port cover 56, a hydrogen filling line 60, a high-pressure supply line 62, and a low-pressure supply line 64.

[0031] The hydrogen tank 50 stores hydrogen to be supplied to the power source 41. The hydrogen tank 50 has, for example, a cylindrical shape.

[0032] A feature of the work machine 1 is that the hydrogen tank 50 is mounted on the work device 30. Specifically, in the first embodiment, as shown in Fig. 1 , the hydrogen tank 50 is fixed to the outer surface of the boom 31. The outer surface is the surface of the boom 31 that faces the side opposite the operator's cab 21 (the front side in Fig. 1 ) of both side surfaces that face in the width direction of the upper rotating structure.

[0033] The hydrogen tank 50 is disposed so as to be located to the side of the outer surface of the boom 31. The hydrogen tank 50 is attached to the outer surface via, for example, a jig that protrudes from the outer surface of the boom 31 outward in the width direction of the upper rotating body (the side opposite the operator's cab 21).

[0034] Because the outer surface of the boom 31 is located on the opposite side from the cab 21, the hydrogen tank 50 fixed to this outer surface is out of the field of view of the operator sitting in the cab 21. This prevents the hydrogen tank 50 from getting in the way of the operator operating the work machine 1. In particular, the hydrogen tank 50 shown in Figure 1 is arranged in a position where the length direction of the hydrogen tank 50 substantially coincides with the boom length direction, which is the length direction of the boom 31, i.e., the direction from the boom base end toward the boom tip end of the boom 31, so the entire length of the hydrogen tank 50 is unlikely to be out of the field of view of the operator sitting in the cab 21.

[0035] 1 is disposed at a position closer to the boom base end than to the intermediate position of the boom 31 in the boom length direction, which reduces the possibility of the hydrogen tank 50 coming into contact with an obstacle or the like during the work operation of the work device 30. In other words, by disposing the hydrogen tank 50 at a position closer to the boom base end than to the intermediate position in the boom length direction, the hydrogen tank 50 is prevented from colliding with an obstacle and being damaged.

[0036] Thus, it is preferable that the hydrogen tank 50 mounted on the working device 30 has a small weight. For example, a lightweight hydrogen tank 50 made of carbon fiber reinforced plastic and glass fiber reinforced plastic is suitable. This is because the heavier the working device 30 is, the lower the lifting performance of the tip attachment 33, for example, the allowable scooping weight of the shovel.

[0037] The hydrogen receiving unit 51 receives hydrogen to be filled and stored in the hydrogen tank 50. The hydrogen receiving unit 51 is also mounted on the work device 30. Specifically, the hydrogen receiving unit 51 is disposed at or near the boom tip of the boom 31. The hydrogen receiving unit 51 has a hydrogen filling port 51a, which is a receiving port (receptacle) that receives a nozzle of a hydrogen dispenser installed at a hydrogen refueling location.

[0038] The hydrogen filling line 60 is arranged so that hydrogen received from the hydrogen dispenser through the hydrogen filling port 51a into the hydrogen receiving part 51 can be filled into the hydrogen tank 50 through the hydrogen filling line 60. Specifically, the hydrogen filling line 60 illustrated in Figures 1 and 2 is arranged to extend along the outer surface of the boom 31 from the hydrogen receiving part 51 arranged at or near the tip of the boom to the hydrogen tank 50 arranged at or near the base of the boom, and is fixed to the outer surface.

[0039] The hydrogen filling line 60 is preferably made of high-pressure piping with high pressure resistance. This is because hydrogen flows through the hydrogen filling line 60 at a pressure as high as the hydrogen filling pressure (e.g., approximately 70 MPa) in the hydrogen tank 50. Therefore, the hydrogen filling line 60 is required to have high strength to achieve the high pressure resistance, and it is also necessary to consider preventing deformation or breakage due to the stress that occurs. Therefore, the hydrogen filling line 60 is preferably made of stainless steel piping with a diameter of, for example, 3 / 8 inch or more.

[0040] The hydrogen receiving section 51 disposed near the boom tip as described above can be positioned at a height accessible to an operator or the like from the ground when the working device 30 is in the boom-lowered position as shown in Fig. 1. The boom-lowered position is a position in which the boom 31 is lowered so that the boom tip approaches the ground, the arm 32 is rotated in the arm-pulling direction so that the arm 32 approaches the ventral surface of the boom 31, i.e., the surface that faces downward when the boom 31 is lowered, and the tip attachment 33 is rotated in the scooping direction relative to the arm 32 so that the tip attachment 33 is positioned between the boom 31 and the arm 32 in the vertical direction. In this position, an operator can easily insert the nozzle of the hydrogen dispenser into the hydrogen filling port 51a on the ground to fill the hydrogen tank 50 with hydrogen.

[0041] The pressure reducing valve 52 is a regulator that reduces the pressure of hydrogen supplied from the hydrogen tank 50 to the power source 41 to a pressure that can be used in the hydrogen fuel cell 41A of the power source 41. The pressure reducing valve 52 is mounted on the work device 30, along with the hydrogen tank 50 and the hydrogen receiving unit 51. In the example shown in Figure 1, the pressure reducing valve 52 is located near the base end of the boom, in the vicinity of the hydrogen inlet and outlet of the hydrogen tank 50.

[0042] The high-pressure supply line 62 and the low-pressure supply line 64 constitute a hydrogen supply line, which allows hydrogen to be supplied from the hydrogen tank 50 to the power source 41 through the hydrogen supply line; specifically, the high-pressure hydrogen discharged from the hydrogen tank 50 is reduced in pressure in the pressure reducing valve 52 before being supplied to the power source 41.

[0043] The high-pressure supply line 62 forms a hydrogen supply path from the hydrogen tank 50 to the pressure reducing valve 52. Specifically, the high-pressure supply line 62 illustrated in Figure 1 is arranged so as to branch off from the hydrogen filling line 60 in the immediate vicinity of the hydrogen tank 50 and lead to the pressure reducing valve 52.

[0044] Like the hydrogen filling line 60, the high-pressure supply line 62 carries hydrogen at a pressure equivalent to the pressure (e.g., about 70 MPa) of hydrogen filled in the hydrogen tank 50. Therefore, like the hydrogen filling line 60, the high-pressure supply line 62 is preferably made of stainless steel piping having a diameter of, for example, 3 / 8 inch or more.

[0045] On the other hand, the low-pressure supply line 64 forms a hydrogen supply path from the pressure reducing valve 52 to the power source 41. That is, the low-pressure supply line 64 enables hydrogen after being reduced in pressure by the pressure reducing valve 52 to be supplied to the power source 41 through the low-pressure supply line 64. Since the pressure reducing valve 52 is mounted on the boom 31 and the power source 41 is mounted on the upper rotating body 20, the low-pressure supply line 64 connecting the two is disposed so as to straddle the boom 31 and the upper rotating body 20. Therefore, it is preferable that the low-pressure supply line 64 be configured to flexibly bend in response to the raising and lowering operation of the boom 31 relative to the upper rotating body 20.

[0046] Because only hydrogen having a low pressure reduced by the pressure reducing valve 52 flows through the low-pressure supply line 64, the low-pressure supply line 64 is not required to have high pressure resistance. Therefore, the low-pressure supply line 64 can be made of flexible piping that is highly flexible and can be easily bent (for example, a hose compatible with hydrogen gas). In other words, the pressure reducing valve 52 mounted on the boom 31 allows the low-pressure supply line 64 located downstream thereof to be made of the flexible piping, thereby enabling hydrogen to be suitably supplied from the hydrogen tank 50 to the power source 41 regardless of the movement of the boom 31 relative to the upper rotating body 20.

[0047] 2 is detachably attached to an appropriate portion of the working device 30, or in the first embodiment, to the outer surface of the boom 31 near the boom base end, so as to cover the hydrogen tank 50 and the pressure reducing valve 52. By covering the hydrogen tank 50 and the pressure reducing valve 52 in this manner, the tank cover 54 prevents foreign matter such as mud, dust, and rainwater from adhering to the hydrogen tank 50 and the pressure reducing valve 52, and also prevents the hydrogen tank 50 and the pressure reducing valve 52 from being exposed to direct sunlight.

[0048] The fill port cover 56 is detachably attached to an appropriate portion of the working device 30, or in the first embodiment, to the outer surface of the boom 31 near the boom tip, so as to cover the hydrogen fill port 51a. By covering the hydrogen fill port 51a in this manner, the fill port cover 56 prevents foreign matter such as mud, dust, and rainwater from adhering to the hydrogen fill port 51a and also prevents the hydrogen fill port 51a from being exposed to direct sunlight.

[0049] The work machine 1 according to the first embodiment described above allows the hydrogen tank 50 to be mounted on the work device 30 so as not to interfere with work performed by the work device 30. Furthermore, unlike the upper rotating body 20 which is equipped with multiple heat sources (for example, the hydrogen fuel cell 41A, the electric motor 41B, and an inverter which controls the drive of the electric motor 41B), the work device 30 is not equipped with such a heat source, and therefore the hydrogen tank 50 mounted on the work device 30 is prevented from being affected by heat from such heat sources.

[0050] Next, a second embodiment of the present invention will be described with reference to Figure 5. Figure 5 shows a boom 31 according to the second embodiment. The boom 31 constitutes a working device of a work machine, and the configuration of this working device is equivalent to the configuration of the working device 30 according to the first embodiment.

[0051] 5 has a curved shape that is convex upward between a boom base end (left end in FIG. 5) 31a and a boom tip end (right end in FIG. 5) 31b in a side view, and at least a portion of the boom 31 (substantially the entire boom 31 in FIG. 5) is hollow and surrounds an internal space. In the second embodiment, a hydrogen tank, a hydrogen receiving portion, and a pressure reducing valve, which are components of a hydrogen supply system, are disposed within the internal space, and these are equivalent to the hydrogen tank 50, the hydrogen receiving portion 51, and the pressure reducing valve 52, respectively, according to the first embodiment.

[0052] The arrangement of the hydrogen tank, hydrogen receiving portion, and pressure reducing valve 52 according to the second embodiment is the same as the arrangement of the hydrogen tank 50, hydrogen receiving portion 51, and pressure reducing valve 52 according to the first embodiment, except that they are located inside the boom 31. That is, in the internal space of the boom 31 according to the second embodiment, the hydrogen tank is located at a position closer to the boom base end 31 a than to the intermediate position in the longitudinal direction of the boom 31, preferably at or near the boom base end 31 a, the hydrogen receiving portion is located at a position closer to the boom tip end 31 b than to the intermediate position, preferably at or near the boom tip 31 b, and the pressure reducing valve is located near the hydrogen inlet and outlet of the hydrogen tank.

[0053] The hydrogen supply system according to the second embodiment also includes a hydrogen filling line, a high-pressure supply line, and a low-pressure supply line similar to the hydrogen filling line 60, the high-pressure supply line 62, and the low-pressure supply line 64 according to the first embodiment, and of these, the entire hydrogen filling line, the entire high-pressure supply line, and a portion of the low-pressure supply line are housed within the internal space of the boom 31, while the other portion of the low-pressure supply line is led out to the outside of the boom 31 as an outlet portion 64d. Specifically, an insertion port 31c that communicates between the inside and outside of the boom 31 is formed in a rear side wall (upper wall in FIG. 5 ) in the vicinity of the boom base end 31a of the boom 31, and a gas pipe that constitutes the low-pressure supply line is inserted into this insertion port 31c. The outlet portion 64d is routed so as to extend from the insertion port 31c to a power source mounted on the upper rotating body of the work machine. At least the outlet portion 64d of the low-pressure supply line is configured by a flexible pipe that can bend in response to the raising and lowering operation of the boom 31 relative to the upper revolving body.

[0054] Meanwhile, a fill port window 31e that opens the hydrogen fill port of the hydrogen receiving section to the side is formed in the side wall of the boom 31, and a fill port door 58 for opening and closing the window 31e is attached to the boom 31. In other words, the work machine according to the second embodiment is provided with the fill port door 58 that can be switched between an open state and a closed state, and the fill port door 58 is configured so that in the open state, the hydrogen fill port is exposed to the outside of the boom 31, allowing the nozzle of the hydrogen dispenser or the like to be inserted into the hydrogen fill port, and so that in the closed state, the fill port door 58 covers the hydrogen fill port.

[0055] In the work apparatus according to the second embodiment described above, the hydrogen tank, the hydrogen receiving portion, and the pressure reducing valve are housed in the internal space of the boom 31, which prevents the hydrogen tank, the hydrogen receiving portion, and the pressure reducing valve from becoming contaminated with mud, dust, rainwater, and other foreign matter, and also prevents the hydrogen tank, the hydrogen receiving portion, and the pressure reducing valve from being exposed to direct sunlight. Furthermore, the hydrogen tank can be mounted on the work apparatus so as not to interfere with work performed by the work apparatus, including the boom 31.

[0056] Next, a third embodiment of the present invention will be described with reference to FIG.

[0057] Figure 6 shows a work machine 1 according to the third embodiment. The components of the work machine 1 are equivalent to the components of the work machine 1 according to the first embodiment, except for the following points. That is, the hydrogen supply system HS of the work machine 1 according to the third embodiment further includes a connection switching unit 66 arranged midway along the low-pressure supply line 64, as shown in Figure 6. The connection switching unit 66 is interposed between an upstream line 64a, which is the upstream portion of the low-pressure supply line 64, and a downstream line 64b, which is the downstream portion of the low-pressure supply line 64. The upstream line 64a is the portion of the low-pressure supply line 64 that is upstream of the connection switching unit 66, i.e., the portion from the pressure reducing valve 52 to the connection switching unit 66, and the downstream line 64b is the portion of the low-pressure supply line 64 that is downstream of the connection switching unit 66, i.e., the portion from the connection switching unit 66 to the power source.

[0058] The connection switching unit 66 can be switched between a connected state and a disconnected state. In the connected state, the connection switching unit 66 connects the upstream line 64 a and the downstream line 64 b to each other, and in the disconnected state, the connection is released, i.e., the upstream line 64 a and the downstream line 64 b are separated from each other.

[0059] For example, the connection switching unit 66 can be configured as a general hydrogen gas coupler. The coupler includes a plug and a socket into which the plug is detachably inserted, with the plug attached to either the downstream end of the upstream line 64a or the upstream end of the downstream line 64b, and the socket attached to the other. When the plug is inserted into the socket, the connection switching unit 66 enters the connected state, and when the plug is removed from the socket, the connection switching unit 66 enters the disconnected state. The coupler is preferably a gas-blocking type that has the function of blocking the release of hydrogen gas in the disconnected state. Alternatively, sealing plugs for sealing in the hydrogen gas may be attached to the plug and the socket, respectively, in the disconnected state.

[0060] The connection switching unit 66 allows, for example, the hydrogen tank 50 of the hydrogen supply system HS shown in FIG. 6 to be used in combination with a hydrogen tank on the aircraft that is different from the hydrogen tank 50.

[0061] The vehicle hydrogen tank is mounted on the vehicle body of the work machine. That is, the vehicle hydrogen tank is mounted on at least one of the upper rotating body 20 and the undercarriage 10. For example, the vehicle hydrogen tank may be either vehicle hydrogen tank 57A or vehicle hydrogen tank 57B shown in FIG. 6. The vehicle hydrogen tank 57A is housed in the machine room 22 included in the upper rotating body 20. The vehicle hydrogen tank 57B is housed inside the travel frame 11 included in the undercarriage 10, for example, inside the central frame 11A.

[0062] The hydrogen tank 50 and the aircraft hydrogen tank can be used together, for example, by normally using hydrogen stored in the aircraft tank and using hydrogen from the hydrogen tank 50 of the hydrogen supply system HS in an emergency when the hydrogen in the aircraft tank runs out. In this case, when hydrogen from the aircraft tank is being used, i.e., during normal operation, the connection switching unit 66 can be set to the disconnected state to disconnect the hydrogen tank 50 from the power source 41. In this way, in the disconnected state, the low-pressure supply line 64 is separated into the upstream line 64a connected to the pressure reducing valve 52 mounted on the work device 30 and the downstream line 64b connected to the power source 41 mounted on the upper rotating structure 20. This prevents stress from occurring in the gas piping that constitutes the low-pressure supply line 64 due to movement of the boom 31 relative to the upper rotating structure 20, and suppresses deterioration of the gas piping due to the stress.

[0063] On the other hand, in an emergency, the connection switching unit 66 can be set to the connected state to supply hydrogen from the hydrogen tank 50 to the power source 41. For example, when the hydrogen in the aircraft tank runs out and the working machine 1 is moving to a hydrogen refueling location, the connection switching unit 66 can be set to the connected state to supply emergency hydrogen from the hydrogen tank 50 of the hydrogen supply system HS to the power source 41. In this case as well, since there is no need to operate the working device 30 relative to the upper rotating body 20 during the movement, stress generation in the gas piping that constitutes the low-pressure supply line 64 is suppressed.

[0064] The present invention is not limited to the above-described embodiments.

[0065] For example, the hydrogen tank 50, the hydrogen receiving portion 51, and the pressure reducing valve 52 according to the third embodiment may also be accommodated in the internal space of the boom 31, as in the second embodiment.

[0066] Furthermore, the location where the hydrogen tank is mounted in the work apparatus is not limited to the outer surface of the boom 31 shown in Fig. 1 and the internal space of the boom 31 shown in Fig. 5. Other examples of locations where the hydrogen tank can be disposed include the outer surface of the boom 31 at or near the tip of the boom, the internal space of the boom 31 at or near the tip of the boom, the outer surface of the arm 32 at or near the tip of the arm 32, and the internal space of the arm 32.

[0067] Furthermore, if it is acceptable for the hydrogen tank 50 to be within the field of view of the operator in the cab 21, the hydrogen tank 50 may be placed on either the side of the boom 31 or the arm 32 that is closer to the cab 21, i.e., the inner side, or on the back of the boom 31 or the arm 32 (the upper surface in the position shown in Figure 1).

[0068] As described above, there is provided a work machine that can be equipped with a hydrogen tank. The work machine includes a lower traveling body, an upper rotating body mounted on the lower traveling body so as to be rotatable relative to the lower traveling body, a work device connected to the upper rotating body and capable of performing work operations that are relative operations with respect to the upper rotating body, a power source mounted on the upper rotating body and generating power using hydrogen as fuel, and a hydrogen supply system that supplies hydrogen to the power source. The hydrogen supply system includes a hydrogen tank that stores hydrogen, and the hydrogen tank is mounted on the work device.

[0069] Specifically, the hydrogen supply system preferably includes a pressure reducing valve and a low-pressure supply line. The pressure reducing valve is mounted on the working device and reduces the pressure of hydrogen supplied from the hydrogen tank to the power source. The low-pressure supply line is disposed across the working device and the upper rotating body so that hydrogen reduced in pressure by the pressure reducing valve can be supplied to the power source through the low-pressure supply line. The combination of the pressure reducing valve and the low-pressure supply line enables hydrogen to be supplied to the power source at an appropriate pressure. Furthermore, because the hydrogen flowing through the low-pressure supply line is reduced in pressure by the pressure reducing valve, the strength required of the members constituting the low-pressure supply line is low.

[0070] In this case, it is preferable that the hydrogen supply system further includes a connection switching unit interposed between the upstream line and the downstream line of the low-pressure supply line, and the connection switching unit is switchable between a connection state in which the upstream line and the downstream line are connected to each other and a connection disconnection state in which the connection is disconnected. The upstream line is the portion of the low-pressure supply line upstream of the connection switching unit, and the downstream line is the portion of the low-pressure supply line downstream of the connection switching unit. In the connection state, the connection switching unit allows hydrogen to be supplied from the hydrogen tank through the low-pressure supply line to the power source, and in the connection disconnection state, the connection switching unit allows the hydrogen tank and the pressure reducing valve to be disconnected from the power source.

[0071] This makes it possible, for example, when the work machine further includes an on-board hydrogen tank that stores hydrogen and is a tank different from the hydrogen tank, to switch the tank to be used between the hydrogen tank and the on-board tank. The on-board hydrogen tank is mounted on the upper rotating body or the undercarriage.

[0072] Preferably, the hydrogen supply system further includes a hydrogen receiving unit including a hydrogen filling port and a hydrogen filling line. The hydrogen receiving unit receives hydrogen to be stored in the hydrogen tank through the hydrogen filling port. The hydrogen filling line interconnects the hydrogen receiving unit and the hydrogen tank so that the hydrogen received in the hydrogen receiving unit can be filled into the hydrogen tank through the hydrogen filling line. The hydrogen receiving unit and the hydrogen filling line enable hydrogen to be replenished into the hydrogen tank as needed.

[0073] Specifically, when the working device includes a boom having a boom base end and a boom tip end opposite the boom base end, and the boom base end is connected to the upper rotating body so that the boom can be raised and lowered relative to the upper rotating body, it is preferable that the hydrogen receiving unit be located at or near the boom tip, which allows ground workers to easily access the hydrogen filling port by setting the working device so that the boom tip is in a low position.

[0074] Meanwhile, it is preferable that the hydrogen tank be located at or near the boom base end. This prevents the moment required to move the boom from increasing due to the weight of the hydrogen tank. In this case, the hydrogen filling line is located along the boom from the hydrogen receiving portion to the hydrogen tank, allowing hydrogen to be filled from the hydrogen receiving portion to the hydrogen tank with a compact structure.

[0075] More specifically, when the upper rotating structure includes a cab and the boom is arranged so that the cab and the boom are aligned in the width direction of the upper rotating structure, the hydrogen tank is preferably arranged on the outer surface of the boom. The outer surface is one of the two sides of the boom that faces away from the cab, and the two sides are the sides of the boom that face the width direction. By arranging the hydrogen tank on the outer surface in this manner, the hydrogen tank is prevented from obstructing the view of the operator in the cab.

[0076] Alternatively, if the boom includes a portion that encloses an interior space, the hydrogen tank may be located within the interior space, which also prevents the hydrogen tank from obstructing the view of the operator in the cab.

Claims

1. A work machine comprising: a lower running body; an upper rotating body mounted on the lower running body so as to be rotatable relative to the lower running body; a work device connected to the upper rotating body and capable of performing work operations which are relative operations to the upper rotating body; a power source mounted on the upper rotating body and which generates power by using hydrogen as fuel; and a hydrogen supply system which supplies hydrogen to the power source, the hydrogen supply system including a hydrogen tank for storing hydrogen, the hydrogen tank being mounted on the work device.

2. A work machine as described in claim 1, wherein the hydrogen supply system is mounted on the work device and includes a pressure reducing valve that reduces the pressure of hydrogen supplied from the hydrogen tank to the power source, and a low-pressure supply line, and the low-pressure supply line is arranged across the work device and the upper rotating body so as to enable hydrogen reduced in pressure by the pressure reducing valve to be supplied to the power source through the low-pressure supply line.

3. A work machine as described in claim 2, wherein the hydrogen supply system further includes a connection switching unit interposed between the upstream line and downstream line of the low-pressure supply line, the connection switching unit being switchable between a connection state in which the upstream line and downstream line are mutually connected and a connection disconnection state in which the connection is disconnected, the upstream line being the portion of the low-pressure supply line upstream of the connection switching unit, and the downstream line being the portion of the low-pressure supply line downstream of the connection switching unit.

4. A work machine as set forth in claim 3, further comprising an aircraft hydrogen tank that is a tank different from the hydrogen tank and stores hydrogen, the aircraft hydrogen tank being mounted on the upper rotating body or the lower running body.

5. A work machine as set forth in any one of claims 1 to 4, wherein the hydrogen supply system further includes a hydrogen receiving section including a hydrogen filling port and a hydrogen filling line, the hydrogen receiving section receiving hydrogen to be stored in the hydrogen tank through the hydrogen filling port, and the hydrogen filling line interconnecting the hydrogen receiving section and the hydrogen tank so as to enable the hydrogen received in the hydrogen receiving section to be filled into the hydrogen tank through the hydrogen filling line.

6. A work machine as set forth in claim 5, wherein the work device includes a boom including a boom base end and a boom tip end opposite the boom base end, the boom base end being connected to the upper rotating body so that the boom can be raised and lowered relative to the upper rotating body, and the hydrogen receiving unit being located at or near the boom tip.

7. A work machine according to claim 6, wherein the hydrogen tank is located at or near the base end of the boom, and the hydrogen filling line is arranged along the boom from the hydrogen receiving section to the hydrogen tank.

8. A work machine as set forth in claim 6 or 7, wherein the upper rotating body includes a cab, the boom is arranged so as to be aligned with the cab in the width direction of the upper rotating body, the hydrogen tank is arranged on the outer surface of the boom, the outer surface being one of both sides of the boom facing away from the cab, and the both sides being sides of the boom facing in the width direction.

9. A work machine according to claim 6 or 7, wherein the boom includes a portion that surrounds an interior space, and the hydrogen tank is disposed within the interior space.

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