Star-shaped hydrogen storage alloy actuator

Abstract

To provide an actuator that is autonomously driven by converting thermal energy into mechanical energy by using release and storage of hydrogen caused by hydrogen storage alloy.SOLUTION: An actuator includes a rotating base, a plurality of output modules, and a motion conversion mechanism coupled to each of the base and the plurality of output modules. The plurality of output modules is mounted to the base so that a direction of translational motion to be output becomes a radial direction around a rotating shaft. The motion conversion mechanism converts the translational motion of the plurality of output modules into rotational motion of the base. Each of the plurality of output modules includes a storage part of the hydrogen storage alloy, an operation part communicated with the storage part and a translational motion part coupled to the operation part. In the operation part, an operating body moves on the basis of pressure of hydrogen that is emitted from the hydrogen storage alloy when a temperature of the storage part is high and that is stored in the hydrogen storage alloy when the temperature is low. The translational motion part performs translational motion along with the movement of the operation body.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to actuator technology, and more particularly to a star-shaped hydrogen storage alloy actuator that can effectively extract power by utilizing pressure changes caused by the release and absorption of hydrogen from a hydrogen storage alloy. [Background technology]

[0002] A hydrogen storage alloy is an alloy that can reversibly absorb and release hydrogen. When cooled, the hydrogen equilibrium pressure decreases, allowing hydrogen to be absorbed, and when heated, the hydrogen equilibrium pressure increases, allowing hydrogen to be released. Generally, a hydrogen storage alloy can absorb hydrogen up to about 1,000 times its volume.

[0003] Various actuators that use hydrogen storage alloys to convert thermal energy into power have been proposed. Patent Document 1 (Japanese Patent No. 4951737) proposes an autonomously driven hydrogen storage alloy actuator. This actuator includes one hydrogen storage alloy module placed in a low-temperature region and another hydrogen storage alloy module placed in a high-temperature region. Rotational motion is derived from the stroke motion generated by the supply of hydrogen from the hydrogen storage alloy or the absorption of hydrogen, and the stroke motion is used to alternately move one module and the other module between the low-temperature region and the high-temperature region, thereby achieving autonomous drive.

[0004] Patent Document 2 (JP-B 1-56270) proposes an automatic rotation actuator that uses a hydrogen storage alloy and utilizes fluctuations in the center of gravity. This actuator has multiple arms arranged radially around an axis, with a membrane-like material, a hydrogen storage alloy, and a bellows arranged radially outward from the arms in this order. The membrane-like material in the arms passes through water, a low-temperature heat source, and air, a high-temperature heat source, in that order. The membrane-like material is cold when passing through water and during the subsequent evaporation of water, but becomes hot when passing through air. The pressure of the hydrogen released and absorbed due to this temperature difference causes the bellows to expand and contract. The expansion and contraction of the bellows changes the distance from the axis to the center of gravity of each arm, and this change in center of gravity is utilized to rotate this multi-arm actuator. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 4951737 [Patent Document 2] Special Publication No. 1-56270 [Patent Document 3] U.S. Patent No. 6,405,532 [Non-patent literature]

[0006] [Non-Patent Document 1] Metal hydride actuator for a rescue jack driven by hydrogen desorption, Minako Hosono, Kouji Sakaki, Yumiko Nakamura, Shuichi Ino, International Journal of Hydrogen Energy, 2019, vol.44, 29310-29318 [Non-patent document 2] Performance simulation of metal hydride based helical spring actuators during hydrogen sorption, PV Jithu, G. Mohan, International Journal of Hydrogen Energy, 2022, 47(33), 14942-14951. [Non-patent document 3] Metal hydride hydrogen compressors: A review, MVLototskyy, et al., International Journal of Hydrogen Energy, 2014, vol.39, 5818-5851 Summary of the Invention [Problem to be solved by the invention]

[0007] The technology of Patent Document 2 utilizes latent heat to generate a temperature difference to adsorb and desorb hydrogen from a hydrogen storage alloy. Therefore, in a device using this technology, hydrogen adsorption and desorption do not occur in an environment where water evaporation is difficult, and automatic rotation is not achieved. Furthermore, this technology uses pressure changes caused by hydrogen adsorption and desorption to extend and retract each arm of the actuator, shifting the center of gravity of each arm to generate rotational force due to gravity. Therefore, the rotation axis is limited to the horizontal direction. Furthermore, with the structure of Patent Document 2, there is a possibility that the internal hydrogen pressure may remain high, and in practice, it is necessary to control the flow of hydrogen inside using a check valve or the like. However, Patent Document 2 does not explicitly state such a structure, and the invention remains incomplete.

[0008] An object of the present invention is to provide an actuator that operates autonomously by converting thermal energy into mechanical energy by utilizing the release and absorption of hydrogen by a hydrogen storage alloy. [Means for solving the problem]

[0009] The object of the present invention can be achieved by arranging a plurality of modules in a star shape, which output translational motion by utilizing the release and absorption of hydrogen by a hydrogen storage alloy, and adopting a mechanism for converting the translational motion of each module into rotational motion by sequentially exposing the hydrogen storage alloy of each module arranged in this manner to high-temperature and low-temperature regions.

[0010] The present invention provides a radial hydrogen storage alloy actuator. This radial hydrogen storage alloy actuator includes a base that rotates about a rotation axis, multiple output modules attached to the base, and a motion conversion mechanism connected to the base and each of the multiple output modules. The multiple output modules each output translational motion, and are attached to the base so that the direction of the translational motion is radially around the rotation axis. The motion conversion mechanism converts the translational motion of the multiple output modules into rotational motion of the base. Each of the multiple output modules has a storage section that stores a hydrogen storage alloy, an actuating section that communicates with the storage section, and a translational section that is connected to the actuating section. The actuating section is configured to move an actuating body based on the pressure of hydrogen released from the hydrogen storage alloy when the storage section is in a high temperature region and stored in the hydrogen storage alloy when the storage section is in a low temperature region. The translational section is configured to perform translational motion in conjunction with the movement of the actuating body.

[0011] The number of modules is preferably three, and the modules are attached to the base so that the directions of their translational motions are at an angle of 120° to each other. The storage unit is preferably configured to alternately pass through a high temperature region and a low temperature region that are arranged in axially symmetrical positions with respect to the rotation axis. The actuating unit preferably has a metal bellows. The translational motion unit preferably has a linear guide and a moving body that moves along the guide as the actuating body is driven.

[0012] In one embodiment, the motion conversion mechanism preferably includes a plurality of rods, each of which has one end rotatably connected to the output module and the other end rotatably fixed at a position eccentric to the rotation axis, the positions at which the other ends of the rods are fixed being the same or adjacent to each other.

[0013] In another embodiment, the motion conversion mechanism preferably includes a master rod and a plurality of sub-rods. One end of the master rod is rotatably connected to a first output module among the plurality of output modules, and the other end is rotatably fixed at a position eccentric from the rotation axis. One end of each of the plurality of sub-rods is rotatably connected to each of the output modules other than the first output module, and the other end is rotatably connected to the other end of the master rod at a position eccentric from the rotation axis of the other end.

[0014] From the viewpoint of effective utilization of low-quality energy, the hydrogen storage alloy in the storage section is preferably capable of chemical reaction at temperatures below 100°C, and more preferably capable of chemical reaction at temperatures below 0°C. [Effects of the Invention]

[0015] According to the present invention, it is possible to provide a star-shaped hydrogen storage alloy actuator that is capable of autonomous rotation with a simple configuration, without the need to use a mechanical mechanism to switch heat sources. [Brief explanation of the drawings]

[0016] [Figure 1] 1 is a schematic diagram showing the structure of a star-shaped hydrogen storage alloy actuator according to one embodiment of the present invention; [Figure 2] 5 is a schematic diagram showing the operation of the output module in the star-shaped hydrogen storage alloy actuator according to one embodiment of the present invention. FIG. [Figure 3A] 1A to 1C are schematic diagrams showing a series of operations of a star-shaped hydrogen storage alloy actuator according to an embodiment of the present invention. [Figure 3B] 1A to 1C are schematic diagrams showing a series of operations of a star-shaped hydrogen storage alloy actuator according to an embodiment of the present invention. [Figure 3C] 1A to 1C are schematic diagrams showing a series of operations of a star-shaped hydrogen storage alloy actuator according to an embodiment of the present invention. [Figure 4] 4 is a graph showing the change over time in the pressure inside the cylinder of the output module in the star-shaped hydrogen storage alloy actuator according to one embodiment of the present invention. [Figure 5] FIG. 1 is a schematic diagram showing an example of an application of the star-shaped hydrogen storage alloy actuator according to one embodiment of the present invention, in which the star-shaped hydrogen storage alloy actuator is used to store water for pumped-storage power generation. DETAILED DESCRIPTION OF THE INVENTION

[0017] The present invention will now be described in detail with reference to the drawings.

[0018] [Structure of star-shaped hydrogen storage alloy actuator] Fig. 1 is a schematic diagram showing the structure of a star-shaped hydrogen storage alloy actuator 1 according to one embodiment of the present invention, and the diagram on the left side of Fig. 1 is a schematic diagram showing the structure of the star-shaped hydrogen storage alloy actuator 1 as viewed from above. The diagram on the right side of Fig. 1 is a schematic diagram showing the structure of an output module. Fig. 2 is a schematic diagram showing the operation of an output module 40. Hereinafter, the star-shaped hydrogen storage alloy actuator 1 will be simply referred to as the actuator 1. The actuator 1 includes, as basic components, a base 20, three output modules 40, and a motion conversion mechanism 60, and is configured so that translational motion output from the three output modules 40 is converted into rotational motion by the motion conversion mechanism 60, causing the base 20 to rotate.

[0019] (base) The base 20 can be a disk that rotates around the rotation axis 21. Cylinders 43a of three output modules 40 are fixed to the base 20 in a radial arrangement centered on the rotation axis 21, and as the output modules 40 rotate, the base 20 also rotates, as described below. For example, by providing a gear or the like on the bottom surface of the base 20, rotational motion can be output from the actuator 1 via the gear. The base 20 is not limited to a circular disk, and may be, for example, a polygonal disk, or a cylinder or polygonal prism. In the case of a cylinder or polygonal prism, the cylinders of the output modules can be attached to the bottom or side of the cylinder or polygonal prism, for example.

[0020] (output module) The three output modules 40 are configured to output translational motion based on the pressure of hydrogen released and absorbed by the hydrogen storage alloy. Each output module 40 has a storage section 41 that stores the hydrogen storage alloy, hydrogen piping 42, an operating section 43 that operates based on the hydrogen pressure, and a translational motion section 44 that performs translational motion in conjunction with the operation of the operating section 43. The structure of the output module 40 will be described later in connection with the operation of the output module 40.

[0021] <Storage section> The storage unit 41 stores the hydrogen storage alloy therein and is connected to the hydrogen pipe 42. The storage unit 41 is configured so that hydrogen can be released from the hydrogen storage alloy and supplied to the hydrogen pipe 42 by external heating, and hydrogen supplied from the hydrogen pipe 42 can be absorbed into the hydrogen storage alloy by external cooling. The structure of the storage unit 41 is not particularly limited as long as it achieves the above-described functions. For example, the storage unit 41 may be configured so that a hydrogen storage alloy formed into a hollow, donut-like columnar shape is stored inside a hollow cylindrical storage vessel. The hollow, cylindrical shape of the hydrogen storage alloy ensures a hydrogen flow path within the storage vessel and accommodates expansion and contraction of the hydrogen storage alloy. The storage vessel is preferably made of a material with good thermal conductivity, such as copper tubing.

[0022] Known hydrogen storage alloys include Ti-Fe alloys, V alloys, AB2 alloys, and AB5 alloys, all of which can be used in the star-shaped hydrogen storage alloy actuator of the present invention. In response to the recent increase in energy demand, there is a demand for effective utilization of low-quality energy. For example, low-temperature thermal energy can be considered low-quality energy. Much of this low-temperature thermal energy is in the temperature range close to room temperature, resulting in low thermal efficiency and difficulty in energy conversion. In particular, in low-temperature regions such as Hokkaido, a vast amount of unused low-temperature thermal energy exists, and technologies for effectively utilizing this low-temperature thermal energy are attracting attention. Therefore, with an emphasis on the effective utilization of low-quality energy, a hydrogen storage alloy that can chemically react at temperatures below 100°C is particularly suitable for the star-shaped hydrogen storage alloy actuator of the present invention. A hydrogen storage alloy that can chemically react at temperatures below 0°C is more preferable. Such a hydrogen storage alloy can be selected, for example, based on the van't Hoff plot, which shows the relationship between temperature and pressure during an equilibrium reaction, as shown in Non-Patent Document 3. As a hydrogen storage alloy particularly suitable for an actuator that can be used at low temperatures, it is more preferable to select a material that exhibits a large difference in hydrogen storage pressure due to temperature change, that is, a material that exhibits a large slope in the van't Hoff plot, for example.

[0023] <Hydrogen piping> The storage section 41 and the operating section 43 are connected to each other by hydrogen via hydrogen piping 42. Hydrogen released from the hydrogen storage alloy is supplied from the storage section 41 to the operating section 43 through the hydrogen piping 42, and hydrogen absorbed in the hydrogen storage alloy is supplied from the operating section 43 to the storage section 41 through the hydrogen piping 42.

[0024] <Operating part> The actuating unit 43 has a cylindrical cylinder 43a and a piston (actuating body) 43c that protrudes partially from the cylinder 43a and moves in the longitudinal direction of the cylinder 43a, and is configured to operate based on the pressure of hydrogen released and stored by the hydrogen storage alloy in the storage unit 41. The output module 40 is arranged so that the piston 43c protrudes from the cylinder 43a radially outward of the actuator 1. A connecting member 43e is connected to the piston 43c, and the connecting member 43e is connected to a translational motion unit 44, which will be described later.

[0025] 1 and 2, the structure and operation of the output module 40 will be described. The output module 40 has an actuating section 43. As described above, the actuating section 43 has a cylindrical cylinder 43a and a piston 43c that protrudes partially from the cylinder 43a and moves in the longitudinal direction of the cylinder 43a. The piston 43c has a flange 43cc that is connected to a connecting member 43e outside the cylinder 43a, and a rod 43cb that is connected to the flange 43cc. An internal space 43b that receives hydrogen from the storage section 41 is provided inside the cylinder 43a, and the hydrogen in the internal space 43b applies pressure to the bellows 43d.

[0026] The cylinder 43a has an expandable and contractible metal bellows 43d inside. The bellows 43d is a bellows-shaped member made of metal, with one end attached to the end of the rod 43cb of the piston 43c and the other end attached to the inner surface of the end in the longitudinal direction of the cylinder 43a. The bellows 43d attached in this manner contracts when the piston 43c moves (advance) in the direction out of the cylinder 43a (radially outward from the actuator 1), and expands when the piston 43c moves (retract) in the direction back into the cylinder 43a (radially inward from the actuator 1).

[0027] There are no particular limitations on the metal that can be used for the bellows 43d as long as it is resistant to hydrogen embrittlement and heat resistance, and metals that are generally used for bellows pumps, such as austenitic stainless steel (e.g., SUS316L), cold-rolled steel, Fe-based heat-resistant alloys (e.g., SUH660), and aluminum alloys (e.g., A6061-T6), can be used as appropriate.

[0028] The hydrogen storage alloy in the storage unit 41 releases hydrogen when it is in the high temperature region (shown as High in FIG. 2), and the released hydrogen is supplied to the internal space 43b of the cylinder 43a through the hydrogen piping 42. When hydrogen is supplied to the internal space 43b, the bellows 43d contracts due to the pressure of the hydrogen, and the piston 43c moves forward. On the other hand, the hydrogen storage alloy in the storage unit 41 absorbs hydrogen when it is in the low temperature region (shown as Low in FIG. 2). As the absorbed hydrogen is supplied from the internal space 43b to the storage unit 41 through the hydrogen piping 42, the hydrogen pressure in the internal space 43b decreases, and the bellows 43d expands due to its restoring force, causing the piston 43c to move backward.

[0029] In another embodiment, instead of an expandable metal bellows, rubber reinforced with reinforced plastic or plastic fiber cloth (see, for example, Non-Patent Document 1), an expandable bag made of a polymer material (see, for example, Patent Document 3), or a hydrogen storage alloy formed into a coil shape (a shape memory coil that absorbs and desorbs hydrogen by utilizing the deformation of the alloy) (see, for example, Non-Patent Document 2) can also be used as appropriate.

[0030] 1, a flange 43cc of a piston 43c of the output module 40 is connected to a connecting member 43e, and when the piston 43c advances, the connecting member 43e moves radially outward of the actuator 1, and when the piston 43c retreats, the connecting member 43e moves radially inward of the actuator 1. The connecting member 43e is connected to a translational motion unit 44.

[0031] <Translational movement part> The translational motion unit 44 has a linear rail 44a, which is a linear guide, and a linear bushing 44b, which is a moving body that moves linearly along the linear rail 44a. The linear rail 44a is disposed so that the rotation axis 21 is located on an extension line of one end of the linear rail 44a and its length extends in the radial direction of the rotation circle of the actuator 1. The linear bushing 44b is connected to a connecting member 43e. Therefore, when the piston 43c advances, the linear bushing 44b moves along the linear rail 44a in a direction away from the rotation axis 21 (radially outward of the actuator 1), and when the piston 43c retreats, the linear bushing 44b moves along the linear rail 44a in a direction toward the rotation axis 21 (radially inward of the actuator 1).

[0032] The three output modules 40 are attached to the base 20 so that the direction of translational motion is the radial direction centered on the rotation axis 21. That is, each of the three output modules 40 is arranged so that the length direction of the linear rail 44a of the translational motion section 44 (or the movement direction of the linear bushing 44b) extends from the rotation axis 21 radially outward of the actuator 1, and the three output modules 40 are attached to the base 20 so that the respective linear rails 44a form angles of 120° with respect to each other.

[0033] <Another form of the actuating part and the translational part> In this embodiment, the output module 40 is configured so that the piston 43c advances radially outward of the actuator 1 when the internal space 43b is pressurized (i.e., when hydrogen is released from the hydrogen storage alloy), and retracts radially inward of the actuator 1 when the internal space 43b is depressurized (i.e., when hydrogen is absorbed into the hydrogen storage alloy). However, the configuration of the output module is not limited to this, and for example, the output module may be configured so that the piston moves in the opposite direction depending on the release and absorption of hydrogen by the hydrogen storage alloy. That is, the output module may be configured so that the piston retracts radially inward of the actuator when the internal space is pressurized (i.e., when hydrogen is released from the hydrogen storage alloy), and retracts radially outward of the actuator when the internal space is depressurized (i.e., when hydrogen is absorbed into the hydrogen storage alloy).

[0034] (Movement conversion mechanism) The motion conversion mechanism 60 converts the translational motion output from the three output modules 40 into motion that rotates the three output modules 40 themselves, i.e., into rotational motion that rotates the base 20 to which the cylinders 43a of the output modules 40 are attached. The motion conversion mechanism 60 has a master rod 61 connected to one of the three output modules 40, sub-rods 62 and 63 connected to the other two of the three output modules 40, respectively, and a fixed plate 64 connected to the master rod 61 and on which the master rod 61 is rotatably supported. In FIG. 1 , of the three output modules 40, the master rod 61 is connected to the output module 40 shown in the upper part of the figure, the sub-rod 62 is connected to the output module 40 shown in the lower right of the figure, and the sub-rod 63 is connected to the output module 40 shown in the lower left of the figure.

[0035] The master rod 61 has one end 61a, the other end 61c, and a shaft 61b connecting the one end 61a and the other end 61c. The one end 61a is rotatably supported by a linear bushing 44b of the output module 40. The other end 61c has a larger diameter than the shaft 61b and is rotatably supported by a fixed plate 64. The position at which the other end 61c is supported by the fixed plate 64, i.e., the position of the rotation axis 61d of the other end 61c, is eccentric from the rotation axis 21. The large-diameter other end 61c preferably has a structure having two flange-shaped disks spaced apart in the longitudinal direction of the rotation axis 61d.

[0036] The sub-rod 62 has one end 62a, the other end 62c, and a shaft 62b connecting the one end 62a and the other end 62c. Similarly, the sub-rod 63 has one end 63a, the other end 63c, and a shaft 63b connecting the one end 63a and the other end 63c. The one ends 62a and 63a are both rotatably supported by the linear bushings 44b of the two output modules 40. The other ends 62c and 63c are both rotatably supported by the other end 61c of the master rod 61, which has a larger diameter. The other ends 62c and 63c are preferably supported while inserted into the gap between the two flange-shaped disks of the other end 61c.

[0037] The positions at which the other ends 62c, 63c are pivotally supported by the other end 61c of the master rod 61 are preferably different from each other and eccentric from the rotation axis 61d of the other end 61c, i.e., the positions at which the rotation axis 61d and the other ends 62c, 63c are pivotally supported are preferably adjacent to each other. In another embodiment, the positions at which the other ends 62c, 63c are pivotally supported by the other end 61c of the master rod 61 may be the same as the rotation axis 61d of the other end 61c. In yet another embodiment, the positions at which the other ends 62c, 63c are pivotally supported by the other end 61c of the master rod 61 may be the same as the rotation axis 61d of the other end 61c.

[0038] With the above configuration, in the motion conversion mechanism 60, the translational motion output from the three output modules 40 moves the master rod 61 and the sub-rods 62, 63 in the radial direction of the actuator 1, and rotational motion of the three output modules 40 is obtained as the master rod 61 and the sub-rods 62, 63 move.

[0039] [Operation of star-shaped hydrogen storage alloy actuator] Next, the operation of the actuator 1 will be described. FIGS. 3A to 3C are schematic diagrams showing a series of operations of the actuator 1 according to one embodiment of the present invention. In FIGS. 3A to 3C, the actuator 1 is shown as having the same configuration as that shown in FIG. 1. A high-temperature region is located on one side of the actuator 1, and a low-temperature region is located on the opposite side of the actuator 1 from the high-temperature region. In other words, the high-temperature region and the low-temperature region are arranged in positions symmetrical with respect to the rotation axis 21. Of the three output modules 40, the output module located at the top in FIG. 3A is designated 40-1, the output module located at the bottom right is designated 40-2, and the output module located at the bottom left is designated 40-3. The three output modules rotate clockwise around the rotation axis 21 in the plan view of FIG. 3. As of FIG. 3A, the output module 40-1 is located midway between the high-temperature region and the low-temperature region, the output module 40-2 is located in the low-temperature region, and the output module 40-3 is located in the high-temperature region. To avoid cluttering the drawings, the reference numbers of the parts of output modules 40-2 and 40-3 that correspond to those of 40-1 are omitted in Fig. 3A. Similarly, the reference numbers of the parts are omitted in Fig. 3B and Fig. 3C.

[0040] In FIG. 3A, the storage section 41 of the output module 40-1 has moved out of the high-temperature region and into a position midway between the high-temperature region and the low-temperature region. As a result, the temperature of the storage section 41 gradually drops, and the hydrogen in the storage section 41 and the cylinder 43a begins to be absorbed by the hydrogen storage alloy. As the hydrogen is absorbed and the hydrogen pressure in the internal space 43b of the output module 40-1 decreases, the bellows 43d in the cylinder 43a expands, the piston 43c retracts radially inward, and the connecting member 43e moves radially inward. As the connecting member 43e moves, the linear bushing 44b operates to push the master rod 61 in the direction of the arrow in FIG. 3A, i.e., toward the rotation axis 61d.

[0041] At the same time in FIG. 3A, the storage section 41 of the power module 40-2 is in the low-temperature region (more specifically, it is still in the low-temperature region, although it is about to leave the low-temperature region). Therefore, in the storage section 41 of the power module 40-2, hydrogen in the storage section 41 and the cylinder 43a is in the process of being absorbed by a hydrogen storage alloy. While the storage section 41 passes through the low-temperature region, hydrogen is absorbed and the hydrogen pressure in the internal space 43b of the power module 40-2 continues to decrease. As a result, the bellows 43d in the cylinder 43a expands, the piston 43c retracts radially inward, and the connecting member 43e moves radially inward. As the connecting member 43e moves, the linear bushing 44b operates to push the sub-rod 62 in the direction of the arrow, i.e., toward the rotation axis 61d. At this point, the storage section 41 of output module 40-2 has been cooled for a longer period of time than the storage section 41 of output module 40-1, so the position of the linear bushing 44b is closer to the rotation axis 21c than the position of the linear bushing 44b of output module 40-1.

[0042] Meanwhile, the storage section 41 of the output module 40-3 is in a high-temperature region and is heated, causing hydrogen to be released from the hydrogen storage alloy. The released hydrogen is supplied from the storage section 41 to the internal space 43b, and the hydrogen pressure in the internal space 43b increases. This hydrogen pressure causes the piston 43c to move radially outward, and the connecting member 43e to move radially outward. As the connecting member 43e moves, the linear bushing 44b operates to retract the sub-rod 63 in the direction of the arrow, i.e., the direction opposite to the rotation axis 61d.

[0043] A rotation axis 61d at the other end 61c of the master rod 61 is rotatably connected to a fixed plate 64 at a position eccentric from the rotation axis 21 of the base 20 (above the rotation axis 21 in FIG. 3), and the other ends 62c and 63c of the sub-rods 62 and 63 are rotatably connected to the other end 61c. Therefore, when the master rod 61 and the sub-rod 62 are pushed toward the rotation axis 61d and the sub-rod 63 is pulled in the direction opposite to the rotation axis 61d by the above operation, a force is applied to the output module 40 for the output modules 40-1 and 40-2 in a direction increasing the distance from, for example, the outermost end of the cylinder 43a to the rotation axis 61d, and a force is applied to the output module 40-3 in a direction decreasing the distance from, for example, the outermost end of the cylinder 43a to the rotation axis 61d. Therefore, a torque that rotates the three output modules 40 in a clockwise direction in FIG. 3 is applied to the three output modules 40.

[0044] At the time shown in Figure 3B, a certain amount of time has passed since Figure 3A, the storage section 41 of the output module 40-1 is in the low-temperature region (more specifically, it is still in the low-temperature region, although it is trying to leave the low-temperature region). Therefore, the temperature of the storage section 41 of the output module 40-1 is lower than it was at the time shown in Figure 3A, and hydrogen is absorbed by the hydrogen storage alloy, further reducing the hydrogen pressure in the internal space 43b. As a result, the bellows 43d in the cylinder 43a expands further. Therefore, the linear bushing 44b of the output module 40-1 operates to push the master rod 61 further toward the rotation axis 61d compared to the time shown in Figure 3A.

[0045] At the same time in Figure 3B, the storage section 41 of the power module 40-2, which was in the low-temperature region in Figure 3A, is now in the high-temperature region. The temperature of the storage section 41 gradually rises, causing hydrogen to be released from the hydrogen storage alloy. The released hydrogen increases the hydrogen pressure in the internal space 43b of the cylinder 43a, causing the piston 43c to move radially outward. Therefore, the linear bushing 44b of the power module 40-2 operates to retract the sub-rod 62 in the direction opposite to the rotation axis 61d, in the opposite direction from that in Figure 3A.

[0046] 3A, the storage section 41 of the output module 40-3, which was in the high-temperature region, has just left the high-temperature region. At this point, hydrogen is still being released from the hydrogen storage alloy, and the pressure of the released hydrogen causes the piston 43c to move radially outward. Therefore, the linear bushing 44b of the output module 40-3 operates to further retract the sub-rod 63 in the direction opposite the rotation axis 61d compared to the point in time shown in FIG. 3A. At this point, the position of the linear bushing 44b of the output module 40-3 is radially farther from the rotation axis 21c than the position of the linear bushing 44b of the output module 40-2.

[0047] At the time shown in FIG. 3C, a certain time has passed since the time shown in FIG. 3B, the storage section 41 of the output module 40-1 is located in the high-temperature region. The temperature of the storage section 41 is rising, and hydrogen is being released from the hydrogen storage alloy. The released hydrogen increases the hydrogen pressure in the internal space 43b of the cylinder 43a, causing the piston 43c to move forward radially outward. Therefore, the linear bushing 44b of the output module 40-1 operates to retract the master rod 61 in the direction opposite to the rotation axis 61d, which is the opposite of the time shown in FIG. 3B.

[0048] The storage section 41 of the power module 40-2, which was entering the high temperature region at the time of Figure 3B, is entering the low temperature region in Figure 3C. As a result, the temperature of the storage section 41 of the power module 40-2 drops, and hydrogen is absorbed by the hydrogen storage alloy, reducing the hydrogen pressure in the internal space 43b. As a result, the bellows 43d in the cylinder 43a expands, and the piston 43c retracts radially inward. Therefore, the linear bushing 44b of the power module 40-2 operates to push the sub-rod 62 toward the rotation axis 61d, in the opposite direction to that at the time of Figure 3B.

[0049] Furthermore, the storage section 41 of the output module 40-3, which was exiting the high-temperature region at the time of Figure 3B, is now exiting the low-temperature region. At this point, the hydrogen storage alloy continues to store hydrogen, the bellows 43d in the cylinder 43a expands further, and the piston 43c retracts radially inward. Therefore, the linear bushing 44b of the output module 40-3 operates to push the sub-rod 63 toward the rotation axis 61d. At this point, the position of the linear bushing 44b of the output module 40-3 is closer to the rotation axis 21c than the position of the linear bushing 44b of the output module 40-2.

[0050] 3B and 3C, the output modules 40-1 to 40-3 and the motion converting mechanism 60 operate in this manner, and therefore, for the reason explained in connection with Fig. 3A, a force that rotates the three output modules 40 in the clockwise direction in Fig. 3 continues to be applied to them in response to the pushing and pulling of the master rod 61 and the sub-rods 62, 63. As a result, the actuator 1 can rotate autonomously.

[0051] Here, we will explain the torque fluctuations of the actuator 1 having three output modules 40-1 to 40-3. Fig. 4 is a graph showing the results of measuring the change over time in the internal pressure of the cylinder 43a in each of the output modules 40-1 to 40-3 of the actuator 1 prototyped by the inventors. The lines for Cylinders 1 to 3 in the graph represent the pressure change in the cylinder 43a of each of the output modules 40-1 to 40-3. The output of the output modules 40-1 to 40-3 changes in response to the change in the internal pressure of the cylinder 43a, and the output of the output modules 40-1 to 40-3 is converted into the torque of the actuator 1, so the change in the internal pressure of each cylinder 43a is linked to the torque fluctuations.

[0052] As shown in FIG. 4, the internal pressure of each cylinder 43a fluctuates over time as the storage units 41 of each of the power modules 40-1 to 40-3 pass through high-temperature and low-temperature regions (or are exposed to high and low temperatures). For example, at the time shown on the left side of FIG. 4, Cylinder 1 has the highest pressure of the three (the corresponding storage unit is in the high-temperature region and hydrogen is being released from the hydrogen storage alloy), and Cylinder 3 has the lowest pressure (the corresponding storage unit is in the low-temperature region and hydrogen is being absorbed into the hydrogen storage alloy). After that, the pressure of Cylinder 1 drops (the corresponding storage unit is leaving the high-temperature region and heading toward the low-temperature region), and Cylinder 3 rises instead (the corresponding storage unit is leaving the low-temperature region and heading toward the high-temperature region). As Cylinder 3 drops, Cylinder 2 rises next. When Cylinder 2 is at low pressure, Cylinder 3 again becomes high-pressure. In this way, output is always obtained from one of the output modules 40-1 to 40-3, allowing the actuator 1 to rotate autonomously. As is clear from Fig. 4, the torque output from one output module fluctuates significantly over time, but by arranging the three output modules in a star shape at equal angles, the torque fluctuations can be leveled out. By further increasing the number of output modules, the torque fluctuations can be further leveled out.

[0053] The number of output modules 40 fixed to the base 20 is not limited to three, but may be two, four, or more. The greater the number of output modules 40, the more even out the torque fluctuations of each output module 40, enabling smoother rotation of the actuator as a whole. Although two output modules may be used, for example, if the two output modules are arranged opposite each other so that the translational motions from the two output modules move along the same straight line, there is a risk that the rotation of the actuator will stop when the two storage sections 41 are in a position that is neither in the high temperature region nor the low temperature region. Therefore, it is more preferable that the number of output modules 40 be three or more. However, as the number of output modules 40 increases, problems arise such as increased costs, a more complex structure, and increased weight.

[0054] Alternatively, the base 20 and the three output modules 40-1 to 40-3 may be combined into one unit, and an actuator may be constructed with multiple units stacked in multiple layers. In this case, from the viewpoint of torque leveling, it is preferable that the output modules between adjacent units are arranged at an angle of 60° to each other when viewed from above. However, as with the actuators of this type, as the number of units increases, problems arise in terms of increased cost, complexity of the structure, and weight.

[0055] [Examples of applications for star-shaped hydrogen storage alloy actuators] FIG. 5 is a schematic diagram showing an example of an application of the actuator 1 according to one embodiment of the present invention, in which the actuator 1 is used to store water for pumped-storage power generation. In this application, the actuator 1 is used as a power generating source for driving an Archimedes pump. Note that Archimedes pumps are not limited to use in pumped-storage power generation applications, and it is well known to those skilled in the art that they are also used to transport slurries and the like in material recycling systems, for example. Therefore, the actuator 1 can also be used in material recycling systems.

[0056] In recent years, pumped-storage power generation systems have been proposed that use wind power as a power source to drive an Archimedes pump, pump water from a low elevation to a high elevation, and then drop the pumped water to generate electricity. This system, for example, works in wind farms, where, when wind speeds are higher than expected and the amount of electricity generated exceeds the power demand, the surplus power is used to drive the Archimedes pump to pump seawater. When wind speeds are low, the power shortage is compensated for by hydroelectric power generation, thereby stabilizing power throughout the system. Instead of wind power generation, the system shown in FIG. 5 uses an actuator according to the present invention as a power source for the Archimedes pump to create a pumped-storage power generation system. This system allows stable operation throughout the year without relying on unstable wind power generation.

[0057] In this system, an Archimedes pump driven by actuator 1 is installed between a reservoir at a high altitude and a water source (e.g., seawater) at a low altitude. Actuator 1 is connected so that its rotating shaft 21 is coaxial with the rotating shaft of the screw on the high altitude side of the Archimedes pump, and when rotating shaft 21 of actuator 1 rotates, the screw of the Archimedes pump rotates and water is pumped up into the reservoir. A transmission is installed between actuator 1 and the Archimedes pump as needed.

[0058] The actuator 1 is installed, for example, as shown in the upper right diagram showing the view of the arrows A-A'. That is, the actuator 1 is installed so that as it rotates, the hydrogen storage alloy storage sections 41 of some of the output modules 40 are located underwater in the water tank, and the storage sections 41 of the other output modules 40 are located in the air. In the summer, the water tank stores cold water, for example, meltwater from snow removal or cold water waste heat, and in the winter, it stores, for example, groundwater.

[0059] A pumped-storage power generation system configured as described above operates as follows. In summer, as described above, cold water such as meltwater is stored in the water tank, and the water temperature is, for example, approximately 0°C to 10°C. In contrast, the outside air temperature in summer is, for example, 20°C or higher, so a high-temperature heat source is located on one side of the actuator 1, and a low-temperature heat source is located on the opposite side of the actuator 1 from the high-temperature heat source. Then, the actuator 1 operates as described with reference to FIG. 3, the three output modules 40 rotate autonomously, rotating the rotating shaft 21, and the Archimedes pump connected to the rotating shaft 21 pumps water from a low location to a reservoir at a high location. The water thus collected is then passed through a generator and dropped down, thereby generating stable electricity.

[0060] In winter, groundwater is stored in the water tank, and the water temperature is, for example, about 15°C to 20°C. Because the outside air temperature in winter is, for example, below 0°C, the placement of the high-temperature and low-temperature heat sources is reversed, but the situation is the same as in summer, with the high-temperature heat source on one side of the actuator 1 and the low-temperature heat source on the opposite side of the actuator 1 from the high-temperature heat source. Therefore, the three output modules 40 rotate autonomously in the same way, and the Archimedes pump pumps up water. By dropping the pumped up water in this way, stable power generation is performed. [Explanation of symbols]

[0061] 1. Star-shaped hydrogen storage alloy actuator 20 base 21 Rotation axis 40 Output Module 41 Hydrogen storage alloy storage section 42 Hydrogen piping 43 Operating unit 43a Cylinder 43b Interior space 43c Piston (actuator) 43d Bellows 43e Connecting member 44 Translational motion part 44a Linear rail (guide) 44b Linear bush (moving body) 60 Motion conversion mechanism 61 Master Rod 61a One end 61b shaft 61c Wider other end 61d Rotation axis 62, 63 Sub-rod 62a, 63a, 62b, 63b shafts 62c, 63c other end 64 Fixed plate High High temperature area Low Low temperature range HM Hydrogen storage alloy

Claims

1. a base that rotates around a rotation axis; a plurality of output modules, each outputting a translational motion, mounted on the base such that the direction of the translational motion is radial about the axis of rotation; a motion conversion mechanism coupled to the base and each of the plurality of output modules, for converting translational motion of the plurality of output modules into rotational motion of the base; Equipped with Each of the plurality of output modules a storage section for storing a hydrogen storage alloy; an actuating unit that is in communication with the storage unit, and that moves an actuating body based on the pressure of hydrogen released from the hydrogen storage alloy when the storage unit is in a high temperature region and absorbed in the hydrogen storage alloy when the storage unit is in a low temperature region; a translational motion unit connected to the actuation unit and performing translational motion in accordance with movement of the actuation body; having Star-shaped hydrogen storage alloy actuator.

2. the motion conversion mechanism has a plurality of rods; one end of each of the plurality of rods is rotatably connected to the output module, and the other end is rotatably fixed at a position eccentric to the rotation axis; The positions at which the other ends of the plurality of rods are fixed are the same position or positions adjacent to each other.

2. The star-shaped hydrogen storage alloy actuator according to claim 1.

3. the motion conversion mechanism includes a master rod and a plurality of sub-rods; one end of the master rod is rotatably connected to a first output module among the plurality of output modules, and the other end is rotatably fixed at a position eccentric from the rotation axis; one end of each of the plurality of sub-rods is rotatably connected to each of the output modules other than the first output module, and the other end is rotatably connected to the other end of the master rod at a position eccentric from the rotation axis of the other end; 2. The star-shaped hydrogen storage alloy actuator according to claim 1.

4. the plurality of modules are three in number and are mounted on the base such that their directions of translation are at an angle of 120° to each other; 2. The star-shaped hydrogen storage alloy actuator according to claim 1.

5. At least the storage section is configured to alternately pass through a high temperature region and a low temperature region that are arranged at positions symmetrical with respect to the rotation axis, 2. The star-shaped hydrogen storage alloy actuator according to claim 1.

6. The hydrogen storage alloy in the storage unit is capable of chemically reacting at a temperature of less than 100°C.

2. The star-shaped hydrogen storage alloy actuator according to claim 1.

7. The hydrogen storage alloy in the storage section is capable of chemically reacting at a temperature of 0°C or less.

7. The star-shaped hydrogen storage alloy actuator according to claim 6.

8. The actuating part has a metal bellows.

2. The star-shaped hydrogen storage alloy actuator according to claim 1.

9. The translational motion unit includes a linear guide and a moving body that moves along the guide as the actuating body is driven. having 2. The star-shaped hydrogen storage alloy actuator according to claim 1.

Images