Construction machine

Abstract

To provide a construction machine that has a hydrogen storage part for storing hydrogen, built into a counterweight and can be moved even with a counterweight removed.SOLUTION: A work front 5 and a detachable counterweight 13 are provided on an upper rotating body 4 of a hydraulic shovel 1, and a hydrogen absorbing alloy 18 is built into the counterweight 13. Hydrogen from the hydrogen absorbing alloy 18 is used to generate electricity in a fuel cell module 17, the electricity is supplied to an electric motor to drive a hydraulic pump, and discharged hydraulic oil is supplied to hydraulic actuators 6a, 7a, and 8a provided in various parts of the hydraulic shovel 1 to operate them. A removable and portable hydrogen tank 29 is housed in a utility room 15 of the upper rotating body 4, and hydrogen from the hydrogen tank 29 can be supplied to the fuel cell module 17 in place of hydrogen from the hydrogen absorbing alloy 18 depending on switching of a selector valve 22.SELECTED DRAWING: Figure 2

Description

[Technical field]

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

[0002] As an example of a construction machine that uses hydrogen as fuel, Patent Document 1 discloses a hydraulic excavator equipped with a fuel cell that generates electricity using hydrogen. Hydrogen stored in a hydrogen storage alloy is supplied to the fuel cell, and the generated electricity is used to operate an electric motor to drive a hydraulic pump, and the discharged hydraulic oil is supplied to hydraulic actuators in various parts of the vehicle body to operate the hydraulic excavator. A work front equipped with an excavation bucket and the like is connected to the front of the hydraulic excavator body, and a counterweight is attached to the rear of the vehicle body to balance the weight of the work front. The hydrogen storage alloy is built into the counterweight, which makes effective use of the weight of the hydrogen storage alloy and reduces the installation space. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2003-213728 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, the counterweight is not always attached to the hydraulic excavator, and for example, the counterweight may be removed when the hydraulic excavator is transported on a trailer, and the counterweight may not be attached when the hydraulic excavator is manufactured. In such a situation, it is not possible to expect a supply of hydrogen from the hydrogen storage alloy built into the counterweight, which causes problems such as problems when loading and unloading the hydraulic excavator onto and from a trailer for transportation, or when moving the hydraulic excavator on a production line.

[0005] The present invention has been made to solve these problems, and its object is to provide a construction machine that has a hydrogen storage unit for storing hydrogen built into the counterweight, and can be moved even with the counterweight removed. [Means for solving the problem]

[0006] In order to achieve the above-mentioned object, the construction machine of the present invention is characterized in that it has a working device and a detachable counterweight mounted on a vehicle body, a first hydrogen storage tank for storing hydrogen built into the counterweight, and a power system that operates a power source using hydrogen supplied from the first hydrogen storage tank as fuel, and further comprises a second hydrogen storage tank mounted on the vehicle body, and a hydrogen switching unit that selectively connects the first hydrogen storage tank and the second hydrogen storage tank to the power source. Effect of the Invention

[0007] According to the construction machine of the present invention, the hydrogen storage unit for storing hydrogen is built into the counterweight, and the machine can be moved even with the counterweight removed. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a side view showing a hydraulic excavator according to an embodiment. [Diagram 2] 1 is a configuration diagram showing a fuel cell system according to a first embodiment. [Diagram 3] This is an oblique view of the interior of the machine room with the door open, viewed diagonally from the front left. [Figure 4] FIG. 2 is a side view showing the counterweight installation / removal device. [Diagram 5] FIG. 13 is a configuration diagram showing a fuel cell system according to a second and third embodiment having a function of automatically switching a switching valve. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] [First embodiment] Hereinafter, a first embodiment in which the present invention is embodied in a hydraulic excavator will be described. Fig. 1 is a side view showing a hydraulic excavator according to this embodiment, and first, a schematic configuration of the hydraulic excavator will be described with reference to Fig. 1. In the following description, the front-rear, left-right, and up-down directions are expressed with reference to an operator riding on the hydraulic excavator.

[0010] A pair of left and right crawlers 3 are provided on a lower traveling structure 2 of the hydraulic excavator 1, and are driven by a hydraulic traveling motor (not shown) to travel the hydraulic excavator 1. An upper rotating structure 4 (corresponding to the "vehicle body" of the present invention) is provided on the lower traveling structure 2, and is driven to rotate by a hydraulic traveling motor (not shown). A multi-jointed work front 5 (corresponding to the "working device" of the present invention) is provided on the front right side of the upper rotating structure 4, and the work front 5 is composed of a boom 6, an arm 7, and a bucket 8. The angle of the boom 6 is changed by a boom cylinder 6a, the angle of the arm 7 is changed by an arm cylinder 7a, and the angle of the bucket 8 is changed by a bucket cylinder 8a.

[0011] A cab 10 is provided on the front left side of the upper rotating body 4, and various operating devices (not shown) provided in the cab 10 are operated by an operator. A fuel tank 11, a utility room 15, a machine room 12, a counterweight 13, etc. are provided on the rear side of the cab 10 on the upper rotating body 4, and a hydraulic unit 14 is mounted in the machine room 12. Although not shown, the hydraulic unit 14 is composed of an electric motor (corresponding to the "power source" of the present invention), a hydraulic pump driven by the electric motor, a hydraulic circuit for switching the hydraulic oil discharged from the hydraulic pump, etc. The hydraulic oil from the hydraulic pump is switched by the hydraulic circuit in response to the operation of the operating device, and is supplied to the hydraulic actuators such as the traveling and rotating hydraulic motors and the cylinders 6c to 8c of the work front 5. This allows the hydraulic excavator 1 to travel, the upper rotating body 4 to rotate, the work front 5 to operate, etc.

[0012] FIG. 2 is a configuration diagram showing the fuel cell system. A fuel cell system 16 is mounted in the utility room 15 of the upper rotating body 4 to drive the electric motor of the hydraulic unit 14. If the fuel cell system 16 were housed in the machinery room 12 together with the hydraulic unit 14, it would be subject to thermal damage from high-temperature hydraulic oil. To avoid this, the fuel cell system 16 is housed in the utility room 15, where the internal temperature is lower.

[0013] The fuel cell system 16 comprises a fuel cell module 17 (corresponding to the "power source" of the present invention) that generates electricity using hydrogen as fuel, a hydrogen storage alloy 18 (corresponding to the "first hydrogen storage device" of the present invention) that absorbs and stores hydrogen, and further auxiliary equipment such as a cooling radiator, a humidifier, and a back pressure valve (not shown), and the operating states of these components are controlled by a controller 19. The control content of the fuel cell system 16 is well known and will not be described in detail, but the controller 19 sequentially calculates the power required for the fuel cell module 17 based on the operation of the operator of the hydraulic excavator 1. Then, in order to achieve the required power, for example, the controller 19 controls the supply amount and humidity of hydrogen and air to the fuel cell module 17, or controls the cooling of the fuel cell module 17 by a radiator, etc.

[0014] The electric power generated by the fuel cell system 16 in this manner is supplied to the electric motor of the hydraulic unit 14, and the hydraulic excavator 1 operates using the electric motor as a power source as described above. In this embodiment, the hydraulic unit 14 and fuel cell system 16 correspond to the "power system" of the present invention.

[0015] FIG. 3 is a perspective view of the interior of the machine room 12 with the door open, seen from the front left. 2 and 3, a switching valve 22 (corresponding to the "hydrogen switching section" of the present invention) is connected to fuel cell module 17 via a hydrogen supply passage 21, and one end of a hydrogen supply hose 23 is connected to the switching valve 22. Hydrogen supply hose 23 is inserted into a communication hole 24a formed in a partition wall 24 between the utility chamber 15 and the machinery chamber 12, and is led into the machinery chamber 12, where a coupler 25 is provided at the other end.

[0016] The hydrogen storage alloy 18 is built into the counterweight 13, and a hydrogen supply passage 26 extends from the hydrogen storage alloy 18 with a coupler 27 at its tip. A communication hole 28a is formed in the rear wall 28 of the machinery room 12, and when the counterweight 13 is attached to the upper rotating body 4, the coupler 27 on the hydrogen storage alloy 18 side is exposed to the interior of the machinery room 12 through the communication hole 28a, and a coupler 25 of the hydrogen supply hose 23 is connected to it.

[0017] A hydrogen tank 29 (corresponding to the "second hydrogen storage device" of the present invention) for storing hydrogen is detachably attached within the utility room 15. The hydrogen tank 29 is set to a smaller capacity than the hydrogen storage alloy 18, which makes it small and lightweight enough to be manually carried by an operator or the like. The hydrogen tank 29 is connected to a switching valve 22 via a hydrogen supply path 30, and the switching valve 22 is switched between two positions, the hydrogen storage alloy 18 side and the hydrogen tank 29 side, in response to the operation of a change-over switch 31. Therefore, hydrogen from the hydrogen storage alloy 18 or hydrogen from the hydrogen tank 29 is selectively supplied to the fuel cell module 17 in response to the switching of the change-over valve 22.

[0018] Next, the procedure for attaching and detaching the counterweight 13 will be described. In a typical hydraulic excavator, the counterweight may be temporarily removed when the hydraulic excavator is transported by a trailer, etc. In addition, in this embodiment, when hydrogen in the hydrogen storage alloy 18 is consumed, the hydrogen storage alloy 18 may be replaced together with the counterweight 13 instead of refilling with hydrogen. For the replacement work, a counterweight detachment device 33 is provided at the rear of the hydraulic excavator 1. The configuration of the counterweight detachment device 33 is well known and will only be briefly described. For example, as shown in FIG. 4, the base ends of a pair of left and right rotating arms 34 (only one is shown) are supported by a shaft 37 at the rear of the upper rotating body 4, and the counterweight 13 can be connected to a connector 35 provided at the tip of the pair of rotating arms 34. The rotating arm 34 rotates about the shaft 37 by a lifting cylinder 36, and the counterweight 13 suspended from the connector 35 rises and falls following an arc-shaped trajectory.

[0019] The counterweight attachment / detachment device 33 operates on the condition that a detachment mode switch (not shown) provided in the operator's cab 10 is operated and a lock lever (not shown) is operated to prevent unintended operation of the hydraulic excavator 1. At this time, the counterweight attachment / detachment device 33 can rotate the rotating arm 34 in any direction by the lifting cylinder 36 in response to the operation of a lifting operation lever 38 (shown in FIG. 3) provided in the machine room 12. This makes it possible to lift the counterweight 13 on the ground surface to the rear of the upper rotating body 4 and fasten it with bolts, or to release the fastening of the counterweight 13 attached to the rear of the upper rotating body 4 and lower it to the ground surface.

[0020] In this embodiment, when the counterweight 13 is removed, the hydrogen storage alloy 18 built in the counterweight 13 is connected to and disconnected from the fuel cell system 16 on the vehicle body side. When removing the counterweight 13 from the upper rotating body 4, the coupler 27 of the hydrogen storage alloy 18 and the coupler 25 of the hydrogen supply hose 23 are separated in advance, thereby disconnecting the hydrogen storage alloy 18 from the fuel cell system 16. After the counterweight 13 is attached to the upper rotating body 4, the coupler 25 of the hydrogen supply hose 23 is connected to the coupler 27 of the hydrogen storage alloy 18 exposed in the machine room 12 through the communication hole 28a in the rear wall 28, thereby connecting the hydrogen storage alloy 18 to the fuel cell system 16.

[0021] Next, the effects of this embodiment will be described. During normal operation, the counterweight 13 is attached to the upper rotating body 4, and the hydrogen storage alloy 18 is connected to the switching valve 22 by connecting the couplers 25, 27, and the switching valve 22 is switched to the hydrogen storage alloy 18 side. Therefore, hydrogen released from the hydrogen storage alloy 18 in response to the pressure reduction operation is supplied to the fuel cell module 17, and the generated electricity is supplied to the electric motor of the hydraulic unit 14 to operate it. As a result, hydraulic oil is supplied from the hydraulic pump to each hydraulic actuator, and the hydraulic excavator 1 operates in response to the operation of the operator.

[0022] By incorporating the heavy hydrogen storage alloy 18 in the counterweight 13, the weight of the hydrogen storage alloy 18 can be effectively used as the counterweight 13. In addition, since there is no longer a need to provide the hydrogen storage alloy 18 on the upper rotating body 4, the space can be diverted to another use, such as for installing other members.

[0023] When the amount of hydrogen remaining in the hydrogen storage alloy 18 becomes low or runs out while the hydraulic excavator 1 is in operation at the work site, the hydrogen storage alloy 18 is replenished with hydrogen, or the counterweight 13 is replaced with another counterweight 13 incorporating a replenished hydrogen storage alloy 18 using the counterweight detachment device 33. Since replenishment with hydrogen requires strict temperature control and requires careful handling of high-pressure hydrogen gas, it is difficult to carry out at the work site. Therefore, equipment is provided at a preset replenishment location to replenish hydrogen and replace the counterweight.

[0024] However, there is a possibility that the hydraulic excavator 1 cannot be moved to the replenishment location due to an insufficient amount of hydrogen remaining in the hydrogen storage alloy 18. In such a case, the operator operates the change-over switch 31 to switch the switching valve 22 to the hydrogen tank 29 side. This causes hydrogen from the hydrogen tank 29 to be supplied to the fuel cell module 17, and the hydraulic excavator 1 continues to operate using the generated electricity. Although the capacity of the hydrogen tank 29 is small compared to the hydrogen storage alloy 18, it has a capacity sufficient for traveling the short distance between the work site and the replenishment location, so the hydraulic excavator 1 can be moved to the replenishment location without any problems.

[0025] After refilling with hydrogen or replacing the counterweight 13 at the refilling location, the switching valve 22 is switched back to the hydrogen storage alloy 18 side, and hydrogen from the hydrogen storage alloy 18 is supplied to the fuel cell module 17. Therefore, the hydraulic excavator 1 can be operated to return to the work site and resume the interrupted work.

[0026] The hydraulic excavator 1 is also moved using the hydrogen tank 29 when the hydraulic excavator 1 is transported by trailer or when the hydraulic excavator 1 is manufactured. In either case, the counterweight 13 may not be attached to the upper rotating body 4, and as a result, the hydraulic excavator 1 cannot be loaded onto or unloaded from a trailer during transportation, and the hydraulic excavator 1 cannot be moved along the manufacturing line during manufacturing. In these cases, too, hydrogen from the hydrogen tank 29 can be supplied to the fuel cell module 17 by switching the switching valve 22 to the hydrogen tank 29 side. Therefore, the hydraulic excavator 1 can be moved even with the counterweight 13 removed, and the hydraulic excavator 1 can be moved to be loaded onto or unloaded from a trailer during transportation, and the hydraulic excavator 1 can be moved along the manufacturing line during manufacturing.

[0027] On the other hand, when the amount of hydrogen in the hydrogen tank 29 decreases due to the movement of the hydraulic excavator 1, it becomes necessary to replenish it. For example, when the hydraulic excavator 1 is moved to a hydrogen replenishment location, hydrogen is replenished into the hydrogen tank together with the hydrogen storage alloy. However, since the hydrogen tank 29 in this embodiment is detachable, the hydrogen tank 29 can be replaced with another hydrogen tank 29 that has already been replenished. Therefore, work by the hydraulic excavator 1 can be resumed more quickly compared to the case where hydrogen is replenished into the current hydrogen tank 29. Furthermore, when replacing the hydrogen tank 29, the operator can transport the hydrogen tank 29 by hand, so that the replacement work can be easily performed without using a crane or the like.

[0028] Furthermore, if the amount of hydrogen remaining in the hydrogen tank 29 is low to begin with, or if the distance from the work site to the replenishment location is longer than expected, there is a possibility that the hydrogen in the hydrogen tank 29 will be consumed completely on the way to the replenishment location of the hydraulic excavator 1. In this case, the hydraulic excavator 1 will become unable to travel and will be unable to reach the replenishment location, making it impossible to replenish hydrogen to the hydrogen storage alloy 18 or to resume work at the work site.

[0029] In such a case, because the hydrogen tank 29 in this embodiment is removable and portable, the operator can remove the hydrogen tank 29 and carry it to a replenishment location, thereby refilling the hydrogen tank 29 with hydrogen and restoring the traveling function of the hydraulic excavator 1. Therefore, the hydraulic excavator 1 can be moved to the replenishment location and hydrogen can be refilled into the hydrogen storage alloy 18, thereby preventing the worst case scenario of being unable to resume work.

[0030] [Second embodiment] The difference from the first embodiment is that the controller 19 has a function of switching the switching valve 22 to the hydrogen tank 29 side when, for example, the hydrogen storage alloy 18 runs out of hydrogen. As shown in Fig. 5, the basic configuration is the same as in the first embodiment, so the differences will be mainly described.

[0031] A pressure sensor 41 (corresponding to the "pressure detection unit" of the present invention) that detects the hydrogen pressure P in the hydrogen supply hose 23 is connected to the input side of the controller 19, and a switching valve 22 is connected to the output side of the controller 19 together with the fuel cell module 17. When the remaining amount of hydrogen in the hydrogen storage alloy 18 decreases, the hydrogen pressure P decreases, and a pressure judgment value P0 is set in advance to judge this state.

[0032] The controller 19 constantly monitors the hydrogen pressure P detected by the pressure sensor 41, and when the pressure P falls below the pressure determination value P0, it determines that hydrogen replenishment is required and switches the switching valve 22 to the hydrogen tank 29 side. In the first embodiment described above, the operator had to manually operate the switching valve 22 to the hydrogen tank 29 side, but in this embodiment, this switching operation is performed automatically. Therefore, the operator is no longer required to operate the switching valve 22, and can concentrate on driving the hydraulic excavator 1 to the hydrogen replenishment location.

[0033] [Third embodiment] The difference from the first embodiment is that the controller 19 has a function of switching the switching valve 22 to the hydrogen storage alloy 18 side when hydrogen is replenished to the hydrogen storage alloy 18 and the couplers 25, 27 are connected. The basic configuration is the same as the second embodiment shown in Fig. 5, so the differences will be mainly described.

[0034] When the couplers 25, 27 are connected after refilling the hydrogen storage alloy 18 with hydrogen and hydrogen begins to be released from the hydrogen storage alloy 18 by depressurizing, the hydrogen pressure P changes from less than the pressure determination value P0 to equal to or greater than the pressure determination value P0. The controller 19 constantly monitors the hydrogen pressure P detected by the pressure sensor 41, and when the pressure P reaches or exceeds the pressure determination value P0, it determines that refilling with hydrogen is complete and switches the switching valve 22 to the hydrogen storage alloy 18 side.

[0035] In the first embodiment, the operator had to manually operate the switching valve 22 to the side of the hydrogen storage alloy 18, but in this embodiment, this switching operation is performed automatically. Therefore, the operator is no longer required to operate the switching valve 22, and can concentrate on driving the hydraulic excavator 1 to the work site. The controller 19 may be provided with the functions of both the second and third embodiments.

[0036] This concludes the description of the embodiments, but the aspects of the present invention are not limited to the first to third embodiments. For example, the above embodiments are embodied in a hydraulic excavator 1, but the present invention is not limited to this and can be applied to any construction machine equipped with a fuel cell module 17. Therefore, the present invention may be applied to, for example, a rolling vehicle that compacts road surfaces such as asphalt, or a wheel loader that loads soil and sand onto a truck.

[0037] In each of the above embodiments, the counterweight 13 has a built-in hydrogen storage alloy 18 as the first hydrogen storage device, and the utility room 15 of the upper rotating body 4 houses a removable and portable hydrogen tank 29 as the second hydrogen storage device, but this is not limited to the above. For example, the counterweight 13 may have a built-in hydrogen tank as the first hydrogen storage device, and the utility room 15 may house a hydrogen storage alloy as the second hydrogen storage device. Furthermore, the hydrogen tank 29 in the utility room 15 may be made non-removable (and therefore non-portable), or the hydrogen tank 29 may be housed in a location other than the utility room 15 of the upper rotating body 4.

[0038] In the above embodiments, hydrogen is supplied from a hydrogen storage alloy or a hydrogen tank to the fuel cell module 17, and the generated electricity is used to operate the electric motor of the hydraulic unit 14 to drive the hydraulic pump, but the present invention is not limited to this. For example, instead of an electric motor, a hydrogen engine that runs on hydrogen as fuel may be used to drive the hydraulic pump of the hydraulic unit 14, and hydrogen may be supplied to the hydrogen engine from a hydrogen storage alloy or a hydrogen tank. In this case, the hydrogen engine corresponds to the "power source" of the present invention, and the hydraulic unit 14 corresponds to the "power system" of the present invention.

[0039] In addition, in each of the above embodiments, the counterweight 13 is detached by the counterweight attachment / detachment device 33 provided at the rear of the upper rotating body 4, but it is not necessary to provide the hydraulic excavator 1 with the counterweight attachment / detachment device 33. For example, a crane may be prepared at the hydrogen replenishment location, and the replacement work of the counterweight 13 may be carried out using this crane. [Explanation of symbols]

[0040] 1. Hydraulic excavator (construction machinery) 4. Upper rotating body (car body) 5 Work front (work equipment) 13 Counterweight 6a Boom cylinder (hydraulic actuator) 7a Arm cylinder (hydraulic actuator) 8a Bucket cylinder (hydraulic actuator) 14 Hydraulic unit 14 (power system) 16 Battery system 16 (power system) 17 Fuel cell module (power source) 18 Hydrogen storage alloy (first hydrogen storage vessel) 19 Controller 22 Switching valve (hydrogen switching section) 29 Hydrogen tank (second hydrogen storage tank) 41 Pressure sensor (pressure detection part)

Claims

1. A construction machine having a vehicle body provided with a working device and a detachable counterweight, a first hydrogen storage tank for storing hydrogen built into the counterweight, and a power system for operating a power source using hydrogen supplied from the first hydrogen storage tank as fuel, A second hydrogen storage device provided in the vehicle body; a hydrogen switching unit that selectively connects the first hydrogen storage unit and the second hydrogen storage unit to the power source; A construction machine comprising:

2. The second hydrogen storage device is detachably provided on the vehicle body.

2. The construction machine according to claim 1 .

3. the power source is a fuel cell module that generates electricity using hydrogen supplied from the first or second hydrogen storage tank as fuel, and an electric motor that operates using the electricity generated by the fuel cell module; The power system is a hydraulic unit that supplies hydraulic oil from a hydraulic pump driven by the electric motor to hydraulic actuators provided in various parts of the construction machine to operate them, and a fuel cell system that includes the fuel cell module.

2. The construction machine according to claim 1 .

4. the power source is a hydrogen engine that is operated using hydrogen supplied from the first or second hydrogen storage tank as fuel, The power system is a hydraulic unit that supplies hydraulic oil from a hydraulic pump driven by the hydrogen engine to hydraulic actuators provided in various parts of the construction machine to operate them.

2. The construction machine according to claim 1 .

5. a pressure detection unit that detects the pressure of hydrogen supplied from the first hydrogen storage tank; A controller for controlling the hydrogen switching unit; Further equipped with The controller switches the hydrogen switching unit to the second hydrogen storage unit when the pressure detected by the pressure detection unit falls below a preset pressure determination value.

2. The construction machine according to claim 1 .

6. a pressure detection unit that detects the pressure of hydrogen supplied from the first hydrogen storage tank; A controller for controlling the hydrogen switching unit; Further equipped with The controller switches the hydrogen switching unit to the first hydrogen storage unit when the pressure detected by the pressure detection unit reaches or exceeds a preset pressure determination value.

2. The construction machine according to claim 1 .

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