Work machine

Abstract

Provided is a work machine (1) using hydrogen as fuel. The work machine (1) comprises: a lower traveling body (10); an upper turning body (20); a motive power source (41); a hydrogen storage unit (50) including at least one hydrogen tank (50t); and a hydrogen supply line (HL). The motive power source (41) generates motive power using hydrogen as fuel, and is mounted on the upper turning body (20). The hydrogen storage unit (50) is mounted on the lower traveling body (10). The hydrogen supply line (HL) is disposed across the lower traveling body (10) and the upper turning body (20) so that hydrogen can be supplied from the hydrogen storage unit (50) to the motive power source (41) through the hydrogen supply line (HL).

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, hydrogen, is stored in a hydrogen tank in the form of a high-pressure gas, and the energy density per unit volume of the hydrogen is lower than that of diesel fuel or the like. This results in a larger space being required to store hydrogen than the space required to store diesel fuel or the like. Therefore, a portion of the counterweight alone cannot store enough hydrogen to operate the work machine for an extended period of time. This results in the need to frequently refill the hydrogen tank mounted on the counterweight with hydrogen, thereby reducing work efficiency.

[0004] On the other hand, the upper rotating body is equipped with many elements in addition to the counterweight, and these many elements include, for example, a driver's seat, a portion to which a work attachment is attached, a hydraulic actuator for moving the work attachment, etc., a pump for supplying pressure oil to the hydraulic actuator, an electric motor for driving the pump, a fuel cell device for supplying power to the electric motor, a cooling device for cooling the fuel cell device, etc. For this reason, it is difficult to secure space in the upper rotating body other than the counterweight to mount another hydrogen tank to make up for the shortage of hydrogen.

[0005] JP 2014-9589 A

[0006] An object of the present invention is to provide a work machine equipped with a power source that uses hydrogen as fuel, and that is capable of efficiently storing hydrogen.

[0007] The present invention provides a work machine including 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 power source mounted on the upper rotating body and configured to generate power by using hydrogen as fuel, a hydrogen storage unit including at least one hydrogen tank for storing hydrogen, and a hydrogen supply line. The hydrogen storage unit is mounted on the lower traveling body. The hydrogen supply line is disposed across the lower traveling body and the upper rotating body so that hydrogen can be supplied from the hydrogen storage unit to the power source via the hydrogen supply line.

[0008] Fig. 1 is a side view of a work machine according to a first embodiment of the present invention. Fig. 2 is a rear view of the work machine according to the first embodiment, with the storage space door and filling port door of the work machine each in a closed state. Fig. 3 is a block diagram showing the drive system of the work machine according to the first embodiment. Fig. 4 is a rear view of the work machine according to the first embodiment, with the storage space door and filling port door of the work machine each in an open state. Fig. 5 is a side view showing a hydrogen supply line and the like according to the first embodiment. Fig. 6 is a side view of the body of a work machine according to a second embodiment of the present invention. Fig. 7 is a side view showing a hydrogen supply line and the like of a work machine according to a third embodiment of the present invention. Fig. 8 is a view showing a hydrogen supply unit according to the third embodiment.

[0009] Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0010] Figures 1 to 5 show a work machine 1 according to a first embodiment of the present invention. The work machine 1 illustrated in Figures 1 to 5 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.

[0011] The work machine 1 includes a lower traveling body 10, an upper rotating body 20, a working device 30, a drive system 40, and a hydrogen supply system. The lower traveling body 10 and the upper rotating body 20 constitute the body of the work machine.

[0012] The undercarriage 10 is capable of traveling on the ground. The undercarriage 10 illustrated in FIG. 2 includes a traveling frame 11 that supports the upper rotating body 20 and a pair of traveling devices 12.

[0013] 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.

[0014] 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 and 2 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 in rear of 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 made of, for example, rubber and is stretched around the front idler, the sprocket, the upper roller, and the lower roller.

[0015] As shown in FIGS. 1 and 2 , 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., a revolving center axis 26 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 part of the drive system 40.

[0016] The working device 30 includes a boom 31, an arm 32, and a tip attachment 33. The boom 31 has a boom base end and a boom tip end on the opposite side, and the boom base end is rotatably connected to the upper rotating body 20 so that the boom 31 can perform a hoisting operation. The hoisting operation is an operation in which the boom 31 rotates so that the boom tip moves up and down relative to the upper rotating body 20. The arm 32 has an arm base end and an arm tip end on the opposite side, and the arm tip is connected to the boom tip so that the arm 32 can rotate up and down relative to the boom 31. The tip attachment 33 constitutes the tip of the working device 30 and is connected to the arm tip so that it can rotate up and down relative to the arm 32. The tip attachment 33 illustrated in FIG. 1 is a bucket.

[0017] 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.

[0018] 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 3, 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.

[0019] 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 through the hydrogen supply system, 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.

[0020] 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.

[0021] The power source 41 may further include a secondary battery (a so-called battery).

[0022] 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.

[0023] The working pump 42 is a hydraulic pump, and is driven by the power source 41 to supply the working oil in the working oil tank 45 to the plurality of hydraulic actuators in the actuator group 44 through the control valve unit 43 .

[0024] The control valve unit 43 includes a plurality of control valves respectively corresponding to the plurality of 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.

[0025] The multiple actuators in the actuator group 44 operate to move multiple movable parts of the work machine 1 by the supply of hydraulic oil controlled by the control valve. Specifically, the multiple actuators include a swing motor 44A, the work actuator group 44B, and a pair of travel motors 44C. 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.

[0026] Next, the hydrogen supply system will be described with reference to Figures 4 and 5. The hydrogen supply system supplies hydrogen, which is fuel, to the power source 41. Specifically, the hydrogen supply system includes the hydrogen storage unit 50, a hydrogen receiving unit 51, a pressure reducing valve 52, and the hydrogen supply line HL. The power source 41 is mounted on the upper rotating body 20, while the hydrogen storage unit 50 is mounted on the lower traveling body 10. The hydrogen supply line HL is disposed across the lower traveling body 10 and the upper rotating body 20 so that hydrogen stored in the hydrogen storage unit 50 can be supplied to the power source 41 through the hydrogen supply line HL.

[0027] In FIG. 5, in order to clearly show the configuration of the hydrogen supply system, the lower traveling body 10 and the upper rotating body 20 on which the hydrogen supply system is mounted are shown by two-dot chain lines.

[0028] The hydrogen storage unit 50 is mounted on the undercarriage 10 and stores hydrogen to be supplied to the power source 41. The hydrogen storage unit 50 includes a plurality of hydrogen tanks 50t, each of which stores hydrogen under high pressure. Each of the hydrogen tanks 50t may be a lightweight hydrogen tank made of carbon fiber reinforced plastic and glass fiber reinforced plastic, as used in hydrogen fuel cell vehicles, for example. The hydrogen storage unit 50 may include only a single hydrogen tank 50t.

[0029] The hydrogen receiving portion 51 allows hydrogen to be stored in the hydrogen storage portion 50 to be filled into the multiple hydrogen tanks 50t through the hydrogen receiving portion 51. Specifically, the hydrogen receiving portion 51 defines a hydrogen receiving space and is incorporated into the traveling frame 11 (more specifically, the central frame 11A) in the example shown in FIGS. 4 and 5 . The hydrogen receiving portion 51 has a hydrogen filling port 51a and is commonly connected to each of the inlets of the multiple hydrogen tanks 50t so as to allow hydrogen introduced into the hydrogen receiving space through the hydrogen filling port 51a to be filled into each of the hydrogen tanks 50t. The hydrogen receiving portion 51 may be formed by a part of the traveling frame 11. That is, the hydrogen receiving space may be defined by a member that constitutes the traveling frame 11.

[0030] 4 and 5 is disposed midway along the hydrogen supply line HL, and allows hydrogen stored in each of the hydrogen tanks 50t to be supplied to the power source 41 through the hydrogen receiving portion 51. In other words, the hydrogen receiving space of the hydrogen receiving portion 51 also functions as part of the hydrogen supply passage.

[0031] The pressure reducing valve 52 has a function of reducing the pressure of the hydrogen supplied from the hydrogen storage unit 50 to the power source 41, i.e., depressurizing the hydrogen, while the hydrogen is being supplied. In other words, the pressure reducing valve 52 enables the high-pressure hydrogen discharged from the hydrogen storage unit 50 to be supplied to the power source 41 at an appropriate pressure after being depressurized by the pressure reducing valve 52.

[0032] 4 and 5, the pressure reducing valve 52 is provided midway along the hydrogen supply line HL and is located between the hydrogen receiving unit 51 and the power source 41. That is, in FIG. 4 and FIG. 5, hydrogen stored in the hydrogen storage unit 50 passes through the hydrogen receiving unit 51 and the pressure reducing valve 52 in this order and is then supplied to the power source 41.

[0033] The hydrogen supply line HL includes a plurality of piping elements for forming a hydrogen supply passage from the hydrogen storage unit 50 to the power source 41. Specifically, the hydrogen supply line HL illustrated in Figures 4 and 5 includes a first high-pressure piping 60, a second high-pressure piping 61, a lower low-pressure piping 63, an inner-joint piping 62, an upper low-pressure piping 64, and a rotary joint 56.

[0034] The first high-pressure piping 60 is arranged to connect the inlets of each of the multiple hydrogen tanks 50t to the common hydrogen receiving section 51. The multiple hydrogen tanks 50t and the hydrogen receiving sections 51 illustrated in Figure 4 are arranged side by side in the width direction of the lower running body (left and right direction in Figure 4), and the first high-pressure piping 60 extends in a direction approximately parallel to the width direction of the lower running body so as to connect the multiple hydrogen tanks 50t and the hydrogen receiving sections 51 to each other. The first high-pressure piping 60 illustrated in Figures 4 and 5 extends in a direction slightly inclined with respect to the width direction of the lower running body when viewed from above, and therefore only a portion of the first high-pressure piping 60 is shown in Figure 5.

[0035] The second high-pressure pipe 61 is arranged to mutually communicate the hydrogen receiving portion 51 and the pressure reducing valve 52. In the example shown in Figure 4, the hydrogen receiving portion 51 is arranged at a position offset to one side (the left side in Figure 4) in the width direction of the upper rotating body from the multiple hydrogen tanks 50t, and the pressure reducing valve 52 is arranged directly above the hydrogen receiving portion 51. Therefore, the second high-pressure pipe 61 extends in the vertical direction between the hydrogen receiving portion 51 and the pressure reducing valve 52.

[0036] A high pressure (e.g., 70 MPa) substantially equivalent to the pressure of hydrogen filled in each of the hydrogen tanks 50t is applied to the first and second high-pressure pipes 60, 61. Therefore, the first and second high-pressure pipes 60, 61 are provided with sufficient strength to withstand this high pressure and are designed to prevent deformation or breakage due to stress generated by the high pressure. For example, each of the first and second high-pressure pipes 60, 61 is preferably made of stainless steel piping material having a diameter of 3 / 8 inch or more.

[0037] The joint inner piping 62 is disposed in a swivel joint 54 shown in Fig. 5 so as to extend in the vertical direction along the central axis of rotation 26 of the upper rotating body 20. The swivel joint 54 is fixed to the traveling frame 11 (more specifically, the central frame 11A) of the lower traveling body 10 and interconnects the lower traveling body 10 and the upper rotating body 20 so as to allow the upper rotating body 20 to rotate about the central axis of rotation 26 relative to the lower traveling body 10 while allowing the joint inner piping 62 in the swivel joint 54 to be kept stationary regardless of the rotation. Specifically, the swivel joint 54 has a cylindrical shape that opens at the top and bottom, and is attached to the lower traveling body 10 at a position where the central axis of the swivel joint 54 coincides with the central axis of the upper rotating body 20.

[0038] The lower low-pressure piping 63 is disposed so as to interconnect the pressure reducing valve 52 and the upstream end (lower end) of the joint internal piping 62. Specifically, the lower low-pressure piping 63 illustrated in Fig. 5 is fixed to the traveling frame 11 (more specifically, the central frame 11A) of the lower traveling body 10 in a position extending from the pressure reducing valve 52 to the upstream end of the joint internal piping 62 in the fore-and-aft direction of the lower traveling body (the traveling direction).

[0039] The upper low-pressure piping 64 is disposed to interconnect the downstream end (upper end) of the intra-joint piping 62 and the power source 41. Specifically, the upper low-pressure piping 64 illustrated in Fig. 5 is fixed to the upper rotating body 20 in an orientation extending rearward in the fore-and-aft direction of the upper rotating body (the direction of the turning radius) from the intra-joint piping 62 to the power source 41, and has a front end which is the upstream end and a rear end which is the downstream end. The front end (upstream end) is connected to the downstream end (upper end) of the intra-joint piping 62 via the rotary coupling 56, and the rear end (downstream end) is connected to the hydrogen fuel cell 41A of the power source 41.

[0040] The rotary joint 56 is connected to the downstream end, i.e., the upper end, of the joint internal piping 62 on the rotation central axis 26, and allows the upper low-pressure piping 64 to rotate around the rotation central axis 26 together with the upper rotating body 20 relative to the joint internal piping 62 while maintaining the interconnection between the joint internal piping 62 and the upper low-pressure piping 64. The rotary joint 56 can be configured, for example, by a rotary joint or a swivel joint.

[0041] The joint internal piping 62, the lower low-pressure piping 63, and the upper low-pressure piping 64 only need to have the capacity to allow the passage of hydrogen gas after it has been depressurized by the pressure reducing valve 52, and are therefore not required to have the same pressure resistance as the first and second high-pressure piping 60, 61. Therefore, the lower low-pressure piping 63 and the upper low-pressure piping 64 can be made of, for example, flexible hydrogen piping whose surface is protected with a wire braid or the like, which makes it possible to easily handle the piping. However, it is not excluded that the lower and upper low-pressure piping 63, 64 can be made of highly rigid piping, for example, stainless steel piping.

[0042] The hydrogen supply line HL according to the first embodiment therefore allows hydrogen stored in the hydrogen storage unit 50 to be supplied to the hydrogen fuel cell 41A of the power source 41 through the first high-pressure piping 60, the hydrogen receiving unit 51, the second high-pressure piping 61, the pressure reducing valve 52, the lower low-pressure piping 63, the joint inner piping 62, the rotary joint 56 and the upper low-pressure piping 64.

[0043] The hydrogen receiving section 51 does not necessarily have to be provided on the hydrogen supply line HL. In other words, the hydrogen supplied from the hydrogen storage section 50 to the power source 41 does not necessarily have to pass through the hydrogen receiving section 51. For example, hydrogen may be filled into the hydrogen tank 50t through a pipe separate from the pipe that constitutes the hydrogen supply line HL.

[0044] The undercarriage 10 of the work machine 1 includes a storage section 13. Specifically, the storage section 13 is included in the travel frame 11 (more specifically, the central frame 11A) of the undercarriage 10, and stores at least the hydrogen storage unit 50 (in this embodiment, the hydrogen storage unit 50 and a portion of the first high-pressure pipe 60). Specifically, the storage section 13 defines a storage space 13s formed within the central frame 11A, and the multiple hydrogen tanks 50t that make up the hydrogen storage unit 50 are disposed within the storage space 13s. In this first embodiment, each of the hydrogen tanks 50t has an axially extending cylindrical shape, its central axis extends in the width direction of the undercarriage (the traveling direction), and is disposed within the storage space 13s with a hydrogen inlet / outlet facing rearward in the fore-and-aft direction (the traveling direction) of the undercarriage. The first high-pressure pipe 60 extends in the accommodation space 13s in a direction substantially parallel to the width direction of the lower running body behind the hydrogen tanks 50t.

[0045] The storage space 13s is open to the rear in the fore-and-aft direction (travel direction) of the undercarriage. That is, the rear end of the storage space 13s is an opening, i.e., a storage section opening, through which the storage space 13s is open to the outside of the central frame 11A. Therefore, the storage section opening allows workers to access the hydrogen storage section 50 and the first high-pressure piping 60. The inlets and outlets of the multiple hydrogen tanks 50t and the first high-pressure piping 60 are arranged along the storage section opening at positions immediately in front of the storage section opening.

[0046] The work machine 1 further includes a storage space door 14 for opening and closing the storage section opening. The storage space door 14 is attached to the rear end of the central frame 11A so as to be movable between a closed position in which the storage section opening is blocked to close the storage space 13s, as shown in Fig. 2, and an open position in which the storage section opening is opened to open the storage space 13s to the rear, as shown in Fig. 4. In the example shown in Figs. 2 and 4, the lower end of the storage space door 14 is connected to the central frame 11A so as to be rotatable about a horizontal axis extending in the width direction of the undercarriage along the lower end of the storage space door 14.

[0047] When the storage space door 14 is in the open position, the storage compartment opening is opened, allowing an operator to access the hydrogen storage unit 50 and the first high-pressure pipe 60 through the storage compartment opening. This makes it possible to check from outside the storage space 13s through the storage compartment opening whether there is an abnormality in the first high-pressure pipe 60, which is part of the hydrogen supply line HL, and whether there is an abnormality in the connection between each hydrogen tank 50t and the first high-pressure pipe 60.

[0048] On the other hand, by closing the storage section opening in the closed position, the storage space door 14 can prevent foreign matter such as mud, dust, and water such as rainwater from entering the storage space 13s through the storage section opening.

[0049] The storage space door 14 is preferably provided with a key for locking the storage space door 14 in the closed position, which makes it possible to prevent people other than a serviceman in charge of maintenance from accidentally touching the first high-pressure pipe 60 through which the high-pressure gas before decompression flows.

[0050] It is preferable that the work machine 1 further includes a hydrogen detector capable of detecting a hydrogen leak, and an alarm that, when the hydrogen detector detects a hydrogen leak, alerts nearby workers and the operator operating the work machine 1. It is preferable that the hydrogen detector be provided, for example, at a position higher than the plurality of hydrogen tanks 50t within the accommodation space 13s.

[0051] The work machine 1 further includes a storage space door detector 72 and a storage space door interlock device 74 shown in FIG.

[0052] The storage space door detector 72 can detect that the storage space door 14 is in the closed position. The storage space door detector 72 includes, for example, a proximity sensor that is located in a position close to the closed position and detects the presence of the storage space door 14.

[0053] The storage space door interlock device 74 restricts the operation of the work machine 1 when the storage space door detector 72 does not detect that the storage space door 14 is in the closed position, that is, performs an interlock related to the opening and closing of the storage space door 14. The storage space door interlock device 74 may be included in a controller 70 that controls the operation of the work machine 1, as shown in FIG. 4 , or may be a device independent of the controller 70. For example, when the storage space door detector 72 does not detect that the storage space door 14 is in the closed position, the storage space door interlock device 74 prohibits the driving of the electric motor 41B regardless of whether or not an operation (switch operation, key operation, etc.) for starting the electric motor 41B has been performed, thereby preventing the operation pump 42 from operating. This prevents the work machine 1 from operating erroneously during maintenance of the hydrogen tank 50t or the first high-pressure piping 60.

[0054] The storage space door interlock device 74 is not limited to one that prohibits the start of the electric motor 41B. For example, the storage space door interlock device 74 may be configured to permit the start of the electric motor 41B but prohibit or suppress the operation of at least a part of the actuator group 44 when it is not detected that the storage space door 14 is in the closed position, that is, to restrict the movement of the actuators corresponding to the operation regardless of the operation given to the operation unit in the driver's cab 21.

[0055] In addition, the storage space door interlock device 74 may be configured to stop the operation of the electric motor 41B when the storage space door detector 72 no longer detects that the storage space door 14 is in the closed position after the electric motor 41B is started, or to prohibit or suppress the movement of the actuator corresponding to the operation regardless of the operation given to the operating unit inside the driver's cab 21.

[0056] The work machine 1 further includes a fill port door 16 shown in Figures 2 and 4. The fill port door 16 is attached to the traveling frame 11 (more specifically, the central frame 11A) so as to enable the hydrogen fill port 51a to be opened and closed.

[0057] 4 and 5, the hydrogen filling port 51a is disposed so as to open to the rear in the fore-and-aft direction of the undercarriage and is housed in a filling port housing chamber 15 formed in the central frame 11A. The filling port housing chamber 15 opens to the rear of the central frame 11A, and the filling port door 16 is attached to the central frame 11A so as to be able to open and close the filling port housing chamber 15, specifically so as to be movable between a closed position shown in FIG. 2 and an open position shown in FIG. 4. When in the open position, the filling port door 16 opens the filling port housing chamber 15 and exposes the hydrogen filling port 51a to the outside of the central frame 11A, thereby allowing an operator to access the hydrogen filling port 51a in the filling port housing chamber 15 from outside the central frame 11A. On the other hand, when in the closed position, the filling port door 16 closes the filling port accommodating chamber 15, i.e., covers the hydrogen filling port 51a, thereby preventing foreign matter such as mud, dust, and water such as rainwater from entering the filling port accommodating chamber 15 and the hydrogen filling port 51a.

[0058] Furthermore, because the fill port door 16 is configured to open and close the hydrogen fill port 51a independently of the storage space door 14, it is possible to prevent a worker accessing the hydrogen fill port 51a from coming into contact with the first high-pressure piping 60. For example, if the worker filling the hydrogen fuel is someone other than a regular serviceman, such as an operator of the work machine 1, the worker can safely perform the filling work without coming into contact with the first high-pressure piping 60 by opening only the fill port door 16 out of the storage space door 14 and the fill port door 16.

[0059] The work machine 1 includes a fill port door detector 76 and a fill port door interlock device 78 shown in FIG.

[0060] The fill port door detector 76 can detect when the fill port door 16 is in the closed position. The fill port door detector 79 can include, for example, a proximity sensor that is located near the closed position and detects the presence of the fill port door 16.

[0061] The fill port door interlock device 78 restricts the operation of the work machine 1 when the fill port door detector 76 does not detect that the fill port door 16 is in the closed position, i.e., performs an interlock related to the fill port door 16. The fill port door interlock device 78 may be included in the controller 70 that controls the operation of the work machine 1, as shown in FIG. 4 , or may be a device independent of the controller 70. For example, when the fill port door detector 76 does not detect that the fill port door 16 is in the closed position, the fill port door interlock device 78 prohibits the driving of the electric motor 41B regardless of whether or not an operation (switch operation, key operation, etc.) to start the electric motor 41B has been performed, thereby preventing the operation pump 42 from operating. This prevents the work machine 1 from operating by mistake during maintenance of the hydrogen tank 50t or the first high-pressure piping 60.

[0062] The filling port door interlock device 78 is not limited to a device that prohibits the start of the electric motor 41B. For example, the filling port door interlock device 78 may be configured to permit the start of the electric motor 41B but prohibit or suppress the operation of at least some of the actuator group 44 when it is not detected that the filling port door 16 is in the closed position, that is, to restrict the movement of the actuators corresponding to the operation regardless of the operation given to the operating unit in the cab 21.

[0063] In addition, the filling port door interlock device 78 may be configured to stop the operation of the electric motor 41B when the filling port door detector 76 no longer detects that the filling port door 16 is in the closed position after the electric motor 41B is started, or to prohibit or suppress the movement of the actuator corresponding to the operation regardless of the operation applied to the operating unit within the driver's cab 21.

[0064] In the work machine 1 according to the first embodiment described above, the hydrogen storage unit 50 including the plurality of hydrogen tanks 50t can be efficiently mounted using the lower traveling body 10.

[0065] There is no limitation on the number of hydrogen tanks 50t included in the hydrogen storage unit 50. The hydrogen storage unit 50 may include only a single hydrogen tank 50t. For example, the hydrogen storage unit 50 may include a single large hydrogen tank having a capacity approximately equal to the total capacity of the five hydrogen tanks 50t shown in FIG.

[0066] The position and orientation of the hydrogen tanks 50t are not limited to those shown in Figures 4 and 5. For example, at least one hydrogen tank 50t may be positioned such that the longitudinal direction of the hydrogen tank 50t is parallel to the width direction of the undercarriage. Furthermore, the hydrogen tanks 50t may be positioned such that the first high-pressure pipe 60 connecting the hydrogen tanks 50t to one another can be fixed to one of the pair of crawler frames 11B. However, such an arrangement may make it difficult for workers to access the first high-pressure pipe 60 due to the crawler frame 11B. In contrast, an arrangement in which the first high-pressure pipe 60 is located behind the hydrogen tanks 50t in the fore-and-aft direction of the undercarriage, as shown in Figures 4 and 5, allows workers to easily access the first high-pressure pipe 60.

[0067] Next, a working machine 1 according to a second embodiment of the present invention will be described with reference to FIG.

[0068] In the first embodiment, the hydrogen filling port 51a and the filling port door 16 that opens and closes it are located below the rear of the upper rotating body 20 as shown in Figure 4 in the basic posture in which the lower traveling body and the upper rotating body are positioned in the fore-and-aft direction, so that an operator needs to enter under the rear of the upper rotating body 20 to fill with hydrogen, whereas in the work machine 1 according to the second embodiment shown in Figure 6, the hydrogen filling port 51a and the filling port door 16 are arranged so that an operator can access the hydrogen filling port 51a from the outside of one of the pair of crawler frames 11B in the width direction of the lower traveling body. Specifically, a filling port accommodation chamber that accommodates the hydrogen filling port 51a is formed in one of the crawler frames 11B, the filling port accommodation chamber opens toward the outside of the crawler frame 11B, and the filling port door 16 that opens and closes the filling port accommodation chamber is attached to the outer surface of the crawler frame 11B. Such an arrangement eliminates the need for workers to enter under the upper rotating body 20 to perform the hydrogen filling operation, thereby enabling the efficiency of the hydrogen filling operation to be increased.

[0069] In the second embodiment, the hydrogen storage unit including at least one hydrogen tank can be efficiently mounted on the lower traveling body 10, similar to the hydrogen storage unit according to the first embodiment.

[0070] Next, a working machine 1 according to a third embodiment of the present invention will be described with reference to FIGS.

[0071] 7 , the working machine 1 according to the third embodiment is equipped with a hydrogen supply line HL, which includes a connection switching unit 66 in addition to the same components as those of the hydrogen supply line HL according to the first embodiment. The connection switching unit 66 is located in the hydrogen supply line HL between the pressure reducing valve 52 and the rotary coupling 56, and is switchable between a connection state in which a downstream line HL1 and an upstream line HL2 of the hydrogen supply line HL are connected to each other, and a connection disconnection state in which the connection is disconnected. The downstream line HL1 is the portion of the hydrogen supply line HL downstream of the connection switching unit 66 (i.e., the side closer to the power source 41), and the upstream line HL2 is the portion of the hydrogen supply line HL upstream of the connection switching unit 66 (i.e., the side closer to the hydrogen storage unit 50).

[0072] 7 , the lower low-pressure piping 63 included in the hydrogen supply line HL is composed of a downstream piping 63a and an upstream piping 63b that are separable from each other, and the connection switching unit 66 is interposed between the downstream piping 63a and the upstream piping 63b. The downstream piping 63a is the portion between the connection switching unit 66 and the in-joint piping 62 in the swivel joint 54, i.e., the portion downstream of the connection switching unit 66, and is therefore included in the downstream line HL1. The upstream piping 63b is the portion between the connection switching unit 66 and the pressure reducing valve 52, i.e., the portion upstream of the connection switching unit 66, and is therefore included in the upstream line HL2. The connection state of the connection switching unit 66 is a state in which the downstream piping 63a and the upstream piping 63b are connected to each other, as shown in FIG. 7 , and the disconnection state is a state in which the downstream piping 63a and the upstream piping 63b are separated from each other.

[0073] The connection switching unit 66 can be configured, for example, by a general hydrogen gas coupler including a plug and a socket into which the plug is detachably inserted. One of the socket and the plug is attached to the upstream end of the downstream line HL1, i.e., the upstream end of the downstream piping 63a in the example shown in FIG. 7 , and the other is attached to the downstream end of the upstream line HL2, i.e., the downstream end of the upstream piping 63b in the example shown in FIG. 7 . Inserting the plug into the socket connects the downstream line HL1 (the downstream piping 63a) and the upstream line HL2 (the upstream piping 63b) to each other. Conversely, removing the plug from the socket disconnects the downstream line HL1 (the downstream piping 63a) and the upstream line HL2 (the upstream piping 63b).

[0074] The coupler is preferably a gas-blocking type that blocks gas from escaping when the plug is removed from the socket and the connection is released.

[0075] The working machine 1 of the third embodiment further includes a unitizing member 80 shown in Figures 7 and 8. In the illustrated example, the unitizing member 80 is a housing that houses, i.e., supports, a hydrogen storage unit 50 including a plurality of hydrogen tanks 50t, a hydrogen receiving unit 51, a pressure reducing valve 52, and a portion of the hydrogen supply line HL, thereby enabling the hydrogen storage unit 50, the hydrogen receiving unit 51, the pressure reducing valve 52, and a portion of the hydrogen supply line HL to be attached to the undercarriage 10 as a single hydrogen supply unit 82. The portion of the hydrogen supply line HL includes a first high-pressure piping 60 that interconnects the plurality of hydrogen tanks 50t and the hydrogen receiving unit 51, a second high-pressure piping 61 that interconnects the hydrogen receiving unit 51 and the pressure reducing valve 52, and a portion of the lower low-pressure piping 63.

[0076] As shown in FIG. 8 , the housing, which is the unitizing member 80, defines an accommodation space 13s and a filling port accommodating chamber 15, respectively, similar to the accommodation space 13s and the filling port accommodating chamber 15 according to the first embodiment. The multiple hydrogen tanks 50t are accommodated in the accommodation space 13s, and the hydrogen filling port 51a of the hydrogen receiving portion 51 is accommodated in the filling port accommodating chamber 15. The accommodation space door 14 and the filling port door 16 shown in FIG. 8 are attached to the housing. The accommodation space door 14, like the accommodation space door 14 according to the first embodiment, is attached to the housing so as to be switchable between a closed state that closes the rear opening of the accommodation space 13s and an open state that opens the rear opening. The filling port door 16, like the filling port door 16 according to the first embodiment, is attached to the housing so as to be switchable between a closed state that closes the rear opening of the filling port accommodating chamber 15 and an open state that opens the rear opening. The filling port door 16 is switched to an open state when hydrogen is filled through the hydrogen filling port 51a, thereby opening the hydrogen filling port 51a to the outside.

[0077] Of the lower low-pressure piping 63, the downstream piping 63a and at least the end (downstream end) of the upstream piping 63b connected to the connection switching unit 66 are arranged outside the hydrogen supply unit 82, that is, outside the unitizing member 80 in this embodiment. This makes it possible to perform the operation for switching the connection switching unit 66 between the connected state and the disconnected state outside the housing, which is the unitizing member 80.

[0078] Furthermore, after the connection switching unit 66 has been switched to the disconnected state, the unitizing member 80 enables the multiple hydrogen tanks 50t, the hydrogen receiving unit 51, and the pressure reducing valve 52 to be removed as a single hydrogen supply unit 82 from the undercarriage 10. Furthermore, by providing the connection switching unit 66 at a position downstream of the pressure reducing valve 52 in the hydrogen supply line HL, the operation of switching the connection switching unit 66 to the disconnected state can be performed safely.

[0079] The unitizing member 80 is not limited to a housing, and may be any member that supports the hydrogen storage unit 50, the hydrogen receiving unit 51, and the pressure reducing valve 52 and enables them to be attached to and detached from the lower running body 10 as a single hydrogen supply unit 82. The unitizing member 80 may be, for example, a frame that supports the hydrogen storage unit 50, the hydrogen receiving unit 51, and the pressure reducing valve 52 and unitizes them.

[0080] The traveling frame 11 of the lower traveling body 10 defines a unit accommodating space that detachably accommodates the hydrogen supply unit 82, which includes the hydrogen storage unit 50, the hydrogen receiving unit 51, the pressure reducing valve 52, and the unitizing member 80, thereby enabling the entire hydrogen supply unit 82 to be detachably accommodated in the traveling frame 11. In the example shown in Figures 7 and 8, the unit accommodating space is formed at the rear end of the center frame 11A of the traveling frame 11 in the fore-and-aft direction of the lower traveling body, and the hydrogen supply unit 82, which includes the unitizing member 80, is detachably attached to this rear end.

[0081] The unitizing member 80 enables the hydrogen storage unit 50, the hydrogen receiving unit 51, and the pressure reducing valve 52 to be easily attached to and detached from the traveling frame 11 as a single hydrogen supply unit. It is also possible for the hydrogen storage unit 50 to be filled with hydrogen at a location remote from the work machine 1.

[0082] The work machine 1 may be provided with a plurality of hydrogen supply units that are attached to the undercarriage 10 so as to be interchangeable with one another, that is, alternatively. This makes it possible to use a hydrogen supply unit of the plurality of hydrogen supply units that is not attached to the undercarriage 10 as a spare unit with hydrogen filled in the hydrogen storage section 50 of that hydrogen supply unit, and to replace that hydrogen supply unit with the spare unit when the remaining amount of hydrogen in the hydrogen storage section 50 of a hydrogen supply unit of the plurality of hydrogen supply units that is mounted on the work machine 1 becomes low, thereby making it possible for the work machine 1 to operate continuously for long periods of time despite the limited amount of hydrogen that can be stored in the hydrogen storage section 50 of each hydrogen supply unit.

[0083] At least one of the connection switching section 66 and the unitizing member 80 according to the third embodiment can also be applied to the work machine 1 according to the first embodiment or the second embodiment.

[0084] As described above, a work machine is provided that is equipped with a power source that uses hydrogen as fuel and is capable of efficiently storing hydrogen. The work machine includes 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 power source mounted on the upper rotating body and that generates power using hydrogen as fuel, a hydrogen storage unit including at least one hydrogen tank for storing hydrogen, and a hydrogen supply line. The hydrogen storage unit is mounted on the lower running body. The hydrogen supply line is arranged across the lower running body and the upper rotating body so that hydrogen can be supplied from the hydrogen storage unit to the power source through the hydrogen supply line.

[0085] In the work machine, the hydrogen storage unit is efficiently arranged in the lower running body, and hydrogen stored in the hydrogen storage unit can be supplied to the power source in the upper rotating body through the hydrogen supply line.

[0086] The working machine preferably further comprises a pressure reducing valve mounted on the undercarriage for reducing the pressure of hydrogen supplied from the hydrogen storage unit to the power source through the hydrogen supply line, the pressure reducing valve enabling hydrogen stored in the hydrogen storage unit to be supplied to the power source at an appropriate pressure.

[0087] The hydrogen supply line preferably includes a rotary joint disposed on the rotation axis of the upper rotating body and an upper pipe disposed on the upper rotating body so as to connect the rotary joint to the power source. The rotary joint allows the upper pipe to rotate around the rotation axis together with the upper rotating body, and enables hydrogen from the hydrogen tank to be supplied to the power source via the rotary joint and the upper pipe.

[0088] It is preferable that the hydrogen supply line further includes a connection switching unit disposed between the hydrogen storage unit and the rotary joint and switchable between a connected state and a disconnected state. In the connected state, the connection switching unit interconnects an upstream line, which is a portion of the hydrogen supply line closer to the hydrogen storage unit than the connection switching unit, with a downstream line, which is a portion of the hydrogen supply line closer to the power source than the connection switching unit, thereby enabling hydrogen to be supplied from the hydrogen storage unit to the power source through the hydrogen supply line. In contrast, when switched to the disconnected state, the connection switching unit disconnects the upstream line and the hydrogen storage unit and other components connected thereto from the power source.

[0089] Preferably, the working machine further includes a hydrogen receiving unit mounted on the undercarriage, the hydrogen receiving unit receiving hydrogen to be stored in the hydrogen storage unit and allowing the hydrogen to be filled into the at least one hydrogen tank of the hydrogen storage unit.

[0090] For example, in a case where the undercarriage includes a pair of crawler frames, the pair of crawler frames are spaced apart in a width direction of the undercarriage perpendicular to the traveling direction of the undercarriage, and each of the crawler frames supports a crawler for traveling of the undercarriage, the hydrogen receiving unit may be located at a position accessible from the outer surface of one of the pair of crawler frames, which allows workers to easily access the hydrogen receiving unit.

[0091] Preferably, the work machine further includes a fill port door that can be switched between an open state and a closed state, the lower traveling body includes a traveling frame that supports the upper rotating body, and a fill port housing chamber that houses the hydrogen fill port of the hydrogen receiving unit is formed within the traveling frame. In the open state, the fill port door opens the fill port housing chamber to the outside of the traveling frame, allowing an operator to access the hydrogen fill port, and in the closed state, closes the fill port housing chamber, preventing foreign matter from entering the fill port housing chamber and the hydrogen fill port.

[0092] In this case, it is preferable that the work machine further comprises a filling port door detector capable of detecting that the filling port door is in a closed state, and a filling port door interlock device that limits the operation of the work machine when the filling port door detector does not detect the closed state. The filling port door interlock device prevents the work machine from operating inadvertently even when the filling port door is not in the closed state.

[0093] The lower traveling body may include a traveling frame, and an accommodation space for accommodating the hydrogen storage unit and a portion of the hydrogen supply line may be formed within the traveling frame.

[0094] It is preferable that the work machine is provided with a hydrogen detector for the storage space, which is preferably provided above the hydrogen storage unit within the storage space and is capable of detecting hydrogen leakage from the hydrogen storage unit or the hydrogen supply line.

[0095] Preferably, the work machine further includes a storage space door that can be switched between a closed state and an open state. In the open state, the storage space door opens the storage space to the outside of the traveling frame, allowing an operator to access the hydrogen storage unit and the like within the storage space, while in the closed state, the storage space door closes the storage space, preventing foreign objects from entering the storage space.

[0096] It is preferable that the work machine further comprises a storage space door detector capable of detecting that the storage space door is in the closed state, and a storage space door interlock device that restricts operation of the work machine when the storage space door detector does not detect that the storage space door is in the closed state. The storage space door interlock device prevents the work machine from operating inadvertently even when the storage space door is not in the closed state.

[0097] When the work machine is equipped with the pressure reducing valve and the hydrogen receiving unit, it is preferable that the hydrogen receiving unit be provided in the hydrogen supply line between the hydrogen storage unit and the pressure reducing valve, which allows the hydrogen received in the hydrogen receiving unit to be filled into the hydrogen tank of the hydrogen storage unit without passing through the pressure reducing valve.

[0098] In this case, it is preferable that the working machine further includes a unitizing member that supports the hydrogen storage unit, the hydrogen receiving unit, and the pressure reducing valve, and enables the hydrogen tank, the hydrogen receiving unit, and the pressure reducing valve to be attached to and detached from the undercarriage as a single hydrogen supply unit.

[0099] Furthermore, it is preferable that the hydrogen supply line includes a connection switching unit located outside the hydrogen supply unit, and the connection switching unit is switchable between a connection state in which an upstream line, which is a portion of the hydrogen supply line closer to the hydrogen storage unit than the connection switching unit, is connected to a downstream line, which is a portion of the hydrogen supply line closer to the power source than the connection switching unit, and a disconnection state in which the connection is disconnected. In the disconnection state, the connection switching unit allows the upstream line and the hydrogen supply unit to be attached to and detached from the undercarriage.

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 power source mounted on the upper rotating body and generating power by using hydrogen as fuel; a hydrogen storage unit mounted on the lower running body and including at least one hydrogen tank for storing hydrogen; and a hydrogen supply line, the hydrogen supply line being arranged across the lower running body and the upper rotating body so as to enable hydrogen to be supplied from the hydrogen storage unit to the power source through the hydrogen supply line.

2. A work machine according to claim 1, further comprising a pressure reducing valve mounted on the undercarriage for reducing the pressure of hydrogen supplied from the hydrogen storage unit to the power source through the hydrogen supply line.

3. A work machine as described in claim 1 or 2, wherein the hydrogen supply line includes a rotary coupling arranged on the central axis of rotation of the upper rotating body, and an upper pipe arranged on the upper rotating body so as to connect the rotary coupling to the power source, and the rotary coupling allows the upper pipe to rotate around the central axis of rotation together with the upper rotating body, while enabling hydrogen from the hydrogen tank to be supplied to the power source side via the rotary coupling and the upper pipe.

4. A working machine as set forth in claim 3, wherein the hydrogen supply line further includes a connection switching unit disposed between the hydrogen storage unit and the rotary coupling, and the connection switching unit is capable of switching between a connection state in which an upstream line, which is a portion of the hydrogen supply line closer to the hydrogen storage unit than the connection switching unit, is connected to a downstream line, which is a portion of the hydrogen supply line closer to the power source than the connection switching unit, and a disconnection state in which the connection is disconnected.

5. A working machine as set forth in claim 1, further comprising a hydrogen receiving section mounted on said undercarriage for receiving hydrogen to be stored in said hydrogen storage section and allowing said hydrogen to be filled into said at least one hydrogen tank of said hydrogen storage section.

6. A work machine according to claim 5, wherein the undercarriage includes a pair of crawler frames, the pair of crawler frames being spaced apart in the width direction of the undercarriage perpendicular to the direction of travel of the undercarriage, each of the crawler frames supporting a crawler for travelling of the undercarriage, and the hydrogen receiving section being located in a position accessible from the outer surface of either one of the pair of crawler frames.

7. A work machine as set forth in claim 5 or 6, further comprising a fill port door, wherein the lower running body includes a running frame supporting the upper rotating body, a fill port accommodating chamber for accommodating the hydrogen filling port of the hydrogen receiving section is formed within the running frame, and the fill port door is switchable between an open state that exposes the fill port accommodating chamber to the outside of the running frame and a closed state that closes the fill port accommodating chamber.

8. A work machine as set forth in claim 7, further comprising a fill port door detector capable of detecting that the fill port door is in a closed state, and a fill port door interlock device that restricts operation of the work machine when the fill port door detector does not detect the closed state.

9. A work machine as set forth in claim 1, wherein the undercarriage includes a traveling frame, and an accommodation space is formed within the traveling frame to accommodate the hydrogen storage unit and a portion of the hydrogen supply line.

10. A work machine as set forth in claim 9, further comprising a hydrogen detector provided in the accommodation space at a position above the hydrogen storage unit, capable of detecting hydrogen leakage from the hydrogen storage unit or the hydrogen supply line.

11. A work machine as set forth in claim 9 or 10, further comprising a storage space door, said storage space door being switchable between an open state that opens said storage space to the outside of said traveling frame and a closed state that closes said storage space.

12. A work machine as set forth in claim 11, further comprising a storage space door detector capable of detecting that the storage space door is in the closed state, and a storage space door interlock device that restricts the operation of the work machine when the storage space door detector does not detect that the storage space door is in the closed state.

13. A working machine as defined in claim 1, further comprising: a pressure reducing valve mounted on the undercarriage for reducing the pressure of hydrogen supplied from the hydrogen storage unit to the power source through the hydrogen supply line; and a hydrogen receiving unit mounted on the undercarriage for receiving hydrogen to be stored in the hydrogen storage unit and allowing the hydrogen to be filled into the at least one hydrogen tank of the hydrogen storage unit, the hydrogen receiving unit being provided on the hydrogen supply line between the hydrogen storage unit and the pressure reducing valve.

14. A work machine according to claim 13, further comprising a unitizing member that supports the hydrogen storage section, the hydrogen receiving section, and the pressure reducing valve, enabling the hydrogen tank, the hydrogen receiving section, and the pressure reducing valve to be attached to and detached from the undercarriage as a single hydrogen supply unit.

15. A work machine as set forth in claim 14, wherein the hydrogen supply line further includes a connection switching unit located outside the hydrogen supply unit, and the connection switching unit is capable of switching between a connection state in which an upstream line, which is a portion of the hydrogen supply line closer to the hydrogen storage unit than the connection switching unit, is connected to a downstream line, which is a portion of the hydrogen supply line closer to the power source than the connection switching unit, and a disconnection state in which the connection is disconnected, and in which the upstream line can be attached and detached together with the hydrogen supply unit to the undercarriage.

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