JP2008215366A - Actuator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide large driving force and a displacement quantity with a simple constitution, in an actuator using a hydrogen storage alloy. <P>SOLUTION: This actuator has a hydrogen storage alloy piece 1 presenting a plate shape and having a difference in a hydrogen absorbing characteristic between its both surfaces, a hydrogen introducing means 3 for storing hydrogen in the hydrogen storage alloy piece 1, a temperature setting means 4 and a pressure reduction means 5 for discharging the hydrogen stored in the hydrogen storage alloy piece 1, and operates with the hydrogen storage alloy piece 1 as an actuator. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an actuator using a hydrogen storage alloy.

Conventionally, as an actuator using a hydrogen storage alloy, a fluid pressure is generated by the absorption and release of hydrogen accompanying heating and cooling of the hydrogen storage alloy, and the driven body is driven by the fluid pressure (see, for example, Patent Documents 1 and 2). Has been proposed.
JP 2005-291289 A JP 7-243409 A

However, in the actuator using the conventional hydrogen storage alloy, the fluid pressure generated by the absorption and release of hydrogen accompanying the heating and cooling of the hydrogen storage alloy is low, so it is necessary to increase the fluid pressure using, for example, an accumulator tank, As a result, there is a problem that the equipment becomes large.
According to the method of driving the driven body using the contraction and expansion of the hydrogen storage alloy itself accompanying the hydrogen storage and release of the hydrogen storage alloy, a large driving force can be obtained, but the contraction amount of the hydrogen storage alloy itself is Since it is extremely small, there is a problem that the driven body cannot be moved by a necessary distance.

  Therefore, an object of the present invention is to obtain a large driving force and displacement with a simple configuration in an actuator using a hydrogen storage alloy.

  The actuator according to the present invention comprises a hydrogen storage alloy piece (1) which has a plate shape and has a difference in hydrogen absorption characteristics between both surfaces, and means for causing the hydrogen storage alloy piece (1) to store hydrogen. And means for discharging the hydrogen stored in the hydrogen storage alloy piece (1), and the hydrogen storage alloy piece (1) serves as an actuator.

In the actuator of the present invention described above, in the process of storing hydrogen in the hydrogen storage alloy piece (1), the hydrogen storage alloy piece (1) is different from the hydrogen storage alloy piece (1 ) The amount of hydrogen absorbed into the surface differs between the two surfaces, and one surface layer in which more hydrogen has been absorbed expands more than the other surface layer, resulting in hydrogen storage alloy pieces ( Bending deformation occurs in 1).
Thereafter, in the process of discharging hydrogen from the hydrogen storage alloy piece (1), the hydrogen storage alloy piece (1) returns to its original shape.
Therefore, the hydrogen storage alloy piece (1) can be used as an actuator by taking out the bending deformation and return operation of the hydrogen storage alloy piece (1) as a reciprocating movement.

In a specific configuration, the environment (2) in which the hydrogen storage alloy piece (1) is disposed includes means for storing hydrogen in the hydrogen storage alloy piece (1), and storage in the hydrogen storage alloy piece (1). Means for discharging the hydrogen that is being discharged are connected.
The means for storing hydrogen in the hydrogen storage alloy piece (1) can be constituted by hydrogen introduction means (3) for supplying high-pressure hydrogen into the environment (2). Further, the means for discharging the hydrogen stored in the hydrogen storage alloy piece (1) includes a temperature setting means (4) for heating the environment (2) and a decompression for reducing the pressure in the environment (2). Means (5).
According to the specific configuration, the hydrogen storage alloy piece (1) can store hydrogen or the hydrogen storage alloy piece (1) can be discharged with simple equipment.

In another specific configuration, the hydrogen storage alloy piece (1) has a hydrogen content between both surfaces depending on the presence or absence of the oxide layer (11) on the both surfaces or the difference in thickness of the oxide layer (11). It has a difference in gas absorption characteristics.
In the specific configuration, for example, by polishing only one surface thereof, it is possible to realize the presence or absence of the oxide layer (11) on both surfaces, or the difference in thickness of the oxide layer (11), Thereby, it is possible to easily give a difference to the absorption characteristics of hydrogen gas on both surfaces of the hydrogen storage alloy piece (1).
As the polishing, buffing or buffing after emery polishing can be employed.

  In a more specific configuration, the hydrogen storage alloy piece (1) outputs a displacement of the free end that accompanies hydrogen storage and discharge, with one end serving as a fixed end and the other end serving as a free end. is there. Thereby, a large displacement can be generated at the free end of the hydrogen storage alloy piece (1).

  Therefore, if the reciprocating mechanism is connected to the free end of the hydrogen storage alloy piece (1), the displacement of the free end of the hydrogen storage alloy piece (1) can be taken out as reciprocation along one direction.

  The actuator according to the present invention has a configuration in which the bending deformation of the hydrogen storage alloy piece is output as a displacement by a simple method that merely gives a difference in hydrogen absorption characteristics between both surfaces of the hydrogen storage alloy piece. Therefore, not only a large displacement amount but also a large driving force can be obtained.

Hereinafter, embodiments of the present invention will be specifically described with reference to the drawings.
As shown in FIG. 1, the actuator according to the present invention is provided with a strip-shaped hydrogen storage alloy piece (1) as an actuator in an environment (2), and both surfaces of the hydrogen storage alloy piece (1). In the meantime, there is a difference in hydrogen absorption characteristics (easiness to pass through).

  Specifically, the oxide layer (11) is formed on one surface Sb of the hydrogen storage alloy piece (1), and the oxide layer (11) is removed by polishing on the other surface Sa. The polishing surface Sa of the hydrogen storage alloy piece (1) allows hydrogen to pass more easily than the non-polishing surface Sb. Further, the non-polished surface Sb is suppressed from absorbing hydrogen by the oxide layer (11).

The environment (2) includes a hydrogen introducing means (3) for storing hydrogen in the hydrogen storage alloy piece (1) and a temperature setting means for discharging the hydrogen stored in the hydrogen storage alloy piece (1). (4) and the decompression means (5) are connected.
It is possible to supply high-pressure (for example, 10 atm) hydrogen gas from the hydrogen introduction means (3) into the environment (2). Further, the environment (2) can be heated from room temperature (25 ° C.) to about 900 ° C. by the temperature setting means (4), and then cooled to room temperature. Furthermore, the inside of the environment (2) can be reduced to a vacuum pressure by the pressure reducing means (5).

For example, as shown in FIG. 2, when high-pressure hydrogen is introduced into the environment (2) in step S1 with the base end of the hydrogen storage alloy piece (1) fixed on the base (10), A large amount of hydrogen is absorbed from the polished surface Sa of the storage alloy piece (1), while almost no hydrogen is absorbed from the non-polished surface SB of the hydrogen storage alloy piece (1).
As a result, a gradient of the hydrogen storage amount occurs in the thickness direction inside the hydrogen storage alloy piece (1), whereby the surface layer on the polishing surface Sa side of the hydrogen storage alloy piece (1) becomes the non-polishing surface Sb. As shown in the drawing, the hydrogen storage alloy piece (1) bends and deforms with the polishing surface Sa as the back surface, and a vertical displacement occurs at the free end of the hydrogen storage alloy piece (1).

  Thereafter, in Step S2, when the environment (2) is heated in a vacuum, hydrogen stored in the hydrogen storage alloy piece (1) is released into the environment (2). As a result, the gradient of the hydrogen storage amount in the hydrogen storage alloy piece (1) disappears, whereby the hydrogen storage alloy piece (1) returns to its original shape. Finally, in step S3, the environment (2) is cooled to room temperature.

  If the above cycle is repeated, the free end of the hydrogen storage alloy piece (1) will reciprocate between the position where the vertical displacement has occurred and the position where it has returned. By taking out this reciprocating movement to the outside, the hydrogen storage alloy piece (1) can be used as an actuator.

  In this way, if the actuator is configured using the hydrogen storage alloy piece (1) as an actuator, a large displacement can be obtained with a simple configuration in which a difference in hydrogen absorption characteristics is simply given to both surfaces of the hydrogen storage alloy piece (1). I can do it. 8 to 20 show the contents and results of an experiment conducted to verify the effect.

As the hydrogen storage alloy piece (1), a Ni—Ti alloy having the composition shown in FIG. 8 was used. The material history of the Ni—Ti alloy is as shown in FIG. Further, the martensite transformation start temperature Ms, martensite transformation end temperature Mf, reverse transformation start temperature As, and reverse transformation end temperature Af of the Ni—Ti alloy are as shown in FIG.
The hydrogen storage alloy piece (1) has a test piece shape with a thickness t of 1 mm as shown in FIG.

As a method of introducing hydrogen into the hydrogen storage alloy piece (1), as shown in FIG. 12, a hydrogen storage alloy piece (1) and a Pt wire (35) surrounding the hydrogen storage alloy piece (1) are set to 0.1. It is soaked in a 9% by mass NaCl aqueous solution (36), and a DC power source (37) is connected to the hydrogen storage alloy piece (1) and the Pt wire (35) to conduct electricity at a current density of 100 A / m ^2. An electrolytic cathodic hydrogen charge was used.

  As a method of giving a difference in hydrogen absorption characteristics on both sides of the hydrogen storage alloy piece (1), a method of polishing only one side of the hydrogen storage alloy piece (1) is adopted, and # 2000 emery polishing and 0.3 μm alumina. Using buffing with powder, as shown in FIG. 13A, four types of test pieces A, B, C, and D having different polishing states were produced.

  Using these test pieces A, B, C, and D, the change in vertical displacement according to the hydrogen introduction time was measured, and the result shown in FIG. 13B was obtained. In specimen A that was neither emery-polished nor buffed, the vertical displacement remained zero even when hydrogen was introduced, whereas in specimen B that was emery-polished only, 6.65 mm in 6 hours. Vertical displacement was obtained. In addition, in the test piece C subjected to only buffing, a vertical displacement of 28.5 mm was obtained in 6 hours, and in the test piece D subjected to both emery polishing and buffing, 25.9 mm was obtained in 6 hours. Vertical displacement was obtained.

  In this way, according to the test piece in which only one surface is emery-polished, a certain amount of vertical displacement is obtained at the free end, and further, buffing is performed after emery polishing, or only buffing is performed. It can be seen that a sufficiently large vertical displacement can be obtained at the free end of the test piece. This is because the oxide layer formed on one side of the test piece is removed by polishing, and the hydrogen absorption characteristics are improved.

14 (a) and 14 (b) show the results of measuring the change in the amount of released hydrogen accompanying the temperature rise of the test pieces A, B, C and D by the temperature rising gas chromatograph method.
In the test piece A, since the oxide layers are still formed on both surfaces, the hydrogen storage amount is small, and as a result, the released hydrogen amount is also small. On the other hand, in test piece B, the hydrogen occlusion amount increased by emery polishing, so the hydrogen released hydrogen amount also increased, and in test pieces C and D, the hydrogen occlusion amount further increased by buffing, The amount of hydrogen released hydrogen is further increased.

  From the results shown in FIGS. 13 (b) and 14 (b), there is a difference in the hydrogen absorption characteristics depending on the polishing state on both surfaces of the hydrogen storage alloy piece (1). It is apparent that the hydrogen storage amount is given a gradient, and bending deformation occurs in the hydrogen storage alloy piece (1) depending on the magnitude of the gradient.

FIG. 15 shows a procedure for measuring the vertical displacement of the test piece C and the test piece F which is different from the test piece C in the presence or absence of the oxidation treatment after buffing. FIG. 16 shows the test piece C and the test piece. The change of the vertical displacement about F is represented. In the test piece F, the oxide layer was formed on both sides by the oxidation treatment after buffing, and the hydrogen absorption characteristics on both sides became the same, so the vertical displacement remained zero. .
FIG. 17 shows the relationship between the temperature and the hydrogen release amount for the test piece F, and the hydrogen release amount becomes a very low value even when the temperature rises.
From the results of FIGS. 16 and 17, it is clear that the presence or absence of the oxide layer affects the hydrogen absorption characteristics on both sides, and vertical displacement occurs due to the removal of the oxide layer.

FIG. 18 shows a test piece G that is buffed on both sides and then oxidized, and then buffed only on one side, and then oxidized and then buffed on both sides and then polished. The procedure for measuring the vertical displacement is shown for the test piece H that is not present, and FIG. 19 shows the change in the vertical displacement for the test piece G and the test piece H.
In the test piece G, the single-side buffing after the oxidation treatment caused a difference in hydrogen absorption characteristics on both sides, so that a large vertical displacement occurred. In the test piece H, the oxidation treatment after the buffing was performed. Thus, after the oxide layer is formed on both sides, the single-sided buffing after the oxidation treatment is omitted, and the hydrogen absorption characteristics on both sides become the same, so the vertical displacement is extremely low.
FIG. 20 shows the relationship between the temperature and the hydrogen release amount for the test piece H, and the hydrogen release amount becomes a low value even when the temperature rises.
From the results of FIG. 19 and FIG. 20, it is clear that the presence or absence of the oxide layer affects the hydrogen absorption characteristics on both sides, and vertical displacement occurs when the oxide layer is removed.

FIG. 3 shows an example in which an actuator is configured using a plurality of hydrogen storage alloy pieces (1). In the actuator, as shown in FIG. 4, a support member (6) is provided at the bottom of the chamber (21), while a cylinder mechanism (7) is provided at the ceiling of the chamber (21). In the chamber (21), the base end portions of the plurality of hydrogen storage alloy pieces (1) are fixed to the support member (6), and the base of the plurality of hydrogen storage alloy pieces (1) is fixed to the cylinder mechanism (7). The ends of the two hydrogen storage alloy pieces (1) and (1) facing each other are connected to each other by elastic connecting pieces (12).
The plurality of hydrogen storage alloy pieces (1) are attached in a posture with the polishing surface Sa facing inward.

A gas introduction pipe (62) passes through the support member (6), and hydrogen gas is introduced into the chamber (21) from the gas introduction pipe (62).
Further, a bellows (71) is provided on the outer peripheral surface of the cylinder mechanism (7) to allow the cylinder mechanism (7) to reciprocate and to seal the inside of the chamber (21).

As shown in FIG. 3, the chamber (21) is installed on the machine base (61), and the gas introduction pipe (62) passes through the support member (6) and the support member (6). 62) is connected to a hydrogen tank (31) and a vacuum pump (51) via a metal hose (34).
A valve (33) and a pressure reducing valve (32) are connected to the outlet of the hydrogen tank (31), and a valve (52) is connected to the outlet of the vacuum pump (51).

A thermocouple (44) is attached to the tip of the gas introduction pipe (62) in the chamber (21), and the thermocouple (44) is connected to the temperature controller (41).
Further, an annular resistance furnace (42) and a water-cooled copper pipe (43) are provided surrounding the outer peripheral surface of the chamber (21) as shown in FIG. 3, and the temperature resistance (41) is provided in the annular resistance furnace (42). Is connected.

  In the actuator, by supplying high-pressure hydrogen gas from the hydrogen tank (31) into the chamber (21), the chamber (21) at room temperature is filled with high-pressure hydrogen gas. The hydrogen is absorbed by the plurality of hydrogen storage alloy pieces (1) in (). Here, since the hydrogen storage alloy piece (1) has a difference in hydrogen absorption characteristics between the polished surface and the non-polished surface, each hydrogen storage alloy piece (1) is bent and deformed with the polished surface as the back surface.

Thereafter, the inside of the chamber (21) is heated by the annular resistance furnace (42) under the control of the temperature controller (41) based on the temperature detection signal from the thermocouple (44), and the chamber ( 21) Depressurize the inside to a vacuum pressure. As a result, the hydrogen storage alloy piece (1) releases hydrogen and returns to its original shape.
Thereafter, the inside of the chamber (21) is cooled to room temperature by flowing cooling water through the water-cooled copper pipe (43).

  The bending deformation and restoration of the hydrogen storage alloy piece (1) described above are converted into reciprocating movement by the cylinder mechanism (7), and the driven part (not shown) in the subsequent stage is driven by the cylinder mechanism (7). .

  FIG. 5 shows a main part of another actuator using the hydrogen storage alloy piece (1) as an actuator. The chamber (21) having the air holes (22) is filled with the electrolyte solution (23). Yes. An insulating support member (82) is attached to the bottom of the chamber (21) via an insulating packing (84), while a cylinder mechanism (7) is attached to the ceiling of the chamber (21).

  In the chamber (21), the base end portions of the plurality of hydrogen storage alloy pieces (1) are fixed to the insulating support member (82), and the plurality of hydrogen storage alloy pieces are fixed to the cylinder mechanism (7). The base end of (1) is fixed, and the free ends of the two hydrogen storage alloy pieces (1) and (1) facing each other are connected by an elastic connecting piece (12).

  The electrode member (8) passes through the insulating support member (82) and its tip protrudes into the electrolyte solution (23), and the conductor (85) passes through the insulating packing (84) and its tip. The part is connected to the hydrogen storage alloy piece (1). The electrode member (8) and the conductive wire (85) are connected to the power supply circuit (83).

In the actuator, a predetermined voltage is applied between the electrode member (8) in the electrolyte solution (23) and each hydrogen storage alloy piece (1) by the power supply circuit (83). Thus, hydrogen is absorbed by the plurality of hydrogen storage alloy pieces (1) in the chamber (21). Here, since the hydrogen storage alloy piece (1) has a difference in hydrogen absorption characteristics between the polished surface and the non-polished surface, each hydrogen storage alloy piece (1) is bent and deformed with the polished surface as the back surface.
The bending deformation of the hydrogen storage alloy piece (1) is transmitted to the cylinder mechanism (7), and the driven part at the rear stage is driven by the cylinder mechanism (7).

FIGS. 6 (a) and 6 (b) show the structure of another actuator using the hydrogen storage alloy piece (1) as an actuator, and the hydrogen storage installed in the environment (2) with the base end fixed. The alloy piece (1) and the electrode piece (91) arranged to face the free end of the hydrogen storage alloy piece (1) constitute a switch circuit for lighting the lamp (9).
When hydrogen is stored in the hydrogen storage alloy piece (1) by introducing hydrogen gas into the environment (2), the hydrogen storage alloy is preferentially introduced into the polishing surface Sa of the hydrogen storage alloy piece (1). The piece (1) is bent and deformed as shown in FIG. 5B, the switch circuit is turned on, and the lamp (9) is lit.
Therefore, the actuator can be applied to detection of hydrogen gas in the environment (2).

FIG. 7 shows the configuration of still another actuator using the hydrogen storage alloy piece (1) as an actuator, and the inside of the hydrogen storage container (26) having a hydrogen inlet (25) and a hydrogen outlet (24). A hydrogen storage alloy piece (1) serving as a valve body that opens and closes the flow path hole (27) is attached. The hydrogen-absorbing alloy piece (1) has a curved shape, the concave curved surface side is a polished surface Sa, and normally the flow path hole (27) is opened.
When excessive hydrogen gas is introduced into the hydrogen storage container (26), the internal pressure of the hydrogen storage container (26) increases, and hydrogen is preferentially introduced into the polishing surface Sa of the hydrogen storage alloy piece (1), The hydrogen storage alloy piece (1) is bent and deformed toward the flat plate shape, and the flow path hole (27) is closed. As a result, the introduction of hydrogen gas into the hydrogen storage container (26) is stopped.
Therefore, the actuator can be used as a device for preventing excessive supply of hydrogen gas into the hydrogen storage container (26).

In addition, each part structure of this invention is not restricted to the said embodiment, A various deformation | transformation is possible within the technical scope as described in a claim. For example, the method for polishing one surface of the hydrogen storage alloy piece (1) is not limited to emery polishing or buff polishing, and electrolytic polishing can also be employed.
Further, the method for giving a difference in hydrogen absorption characteristics on both surfaces of the hydrogen storage alloy piece (1) is not limited to the method of improving the hydrogen absorption characteristics by subjecting one surface to polishing or the like. It is also possible to employ a method for performing a treatment for reducing the absorption characteristics.
Furthermore, the material of the hydrogen storage alloy piece (1) is not limited to the NiTi alloy, and various known hydrogen storage alloys having a large deformability can be employed.
Furthermore, the present invention can be applied to various actuators other than the above as long as it is used as an actuator for the hydrogen storage alloy piece (1).

It is a figure which shows the structure of the actuator which concerns on this invention. It is a figure explaining operation | movement of the actuator which concerns on this invention. It is a figure which shows the application example of the actuator which concerns on this invention. It is a figure which shows the principal part of this application example. It is a figure which shows the principal part of another application example. It is a figure explaining the principle of another application example. It is a figure explaining the principle of another application example. It is a chart which shows the composition of a test piece. It is a graph which shows the raw material log | history of a test piece. It is a graph which shows the transformation and reverse transformation characteristic of a test piece. It is a top view which shows the shape of a test piece. It is a figure explaining the hydrogen introduction | transduction method to a test piece. It is a figure which shows the grinding | polishing state of test piece AD, and the change of a vertical displacement. It is a figure which shows the grinding | polishing state of test piece AD, and the change of the amount of discharge | released hydrogen. 4 is a flowchart showing a vertical displacement measurement procedure for test pieces C and F. 5 is a graph showing changes in vertical displacement for test pieces C and F. 5 is a graph showing a change in hydrogen release amount for test piece F. FIG. It is a flowchart showing the vertical displacement measurement procedure about the test pieces G and H. It is a graph showing the change of the vertical displacement about the test pieces G and H. 5 is a graph showing a change in hydrogen release amount for test piece H.

Explanation of symbols

(1) Hydrogen storage alloy pieces
(2) Environment
(3) Hydrogen introduction means
(4) Temperature setting means
(5) Pressure reducing means Sa Polished surface Sb Non-polished surface

Claims (12)

  A hydrogen storage alloy piece (1) which has a plate shape and has a difference in hydrogen absorption characteristics between both surfaces thereof, means for storing hydrogen in the hydrogen storage alloy piece (1), and the hydrogen storage alloy piece ( 1) means for discharging the stored hydrogen, and an actuator using the hydrogen storage alloy piece (1) as an actuator.   2. The actuator according to claim 1, wherein one surface of the hydrogen storage alloy piece (1) is subjected to a treatment for improving hydrogen absorption characteristics as compared with the other surface.   2. The actuator according to claim 1, wherein one surface of the hydrogen storage alloy piece (1) is subjected to a treatment for lowering hydrogen absorption characteristics than the other surface.   The environment (2) in which the hydrogen storage alloy piece (1) is disposed includes means for allowing the hydrogen storage alloy piece (1) to store hydrogen, and hydrogen stored in the hydrogen storage alloy piece (1). The actuator according to any one of claims 1 to 3, wherein means for discharging the gas is connected.   The actuator according to claim 4, wherein the means for storing hydrogen in the hydrogen storage alloy piece (1) supplies high pressure hydrogen into the environment (2).   The actuator according to claim 4, wherein the means for storing hydrogen in the hydrogen storage alloy piece (1) introduces hydrogen from the electrolytic solution in the environment (2) into the hydrogen storage alloy piece (1).   The means for discharging the hydrogen stored in the hydrogen storage alloy piece (1) includes a temperature setting means (4) for heating the environment (2), and a pressure reducing means for reducing the pressure in the environment (2). The actuator according to claim 4, comprising: (5).   The hydrogen storage alloy piece (1) has a difference in hydrogen gas absorption characteristics between both surfaces depending on the presence or absence of the oxide layer (11) on both surfaces or the difference in thickness of the oxide layer (11). The actuator according to any one of claims 1 to 7.   The hydrogen-absorbing alloy piece (1) is polished on only one surface thereof, and a difference is given in the presence or absence or thickness of the oxide layer (11) on both sides. The actuator according to claim 2, which has a difference of The actuator according to claim 9, wherein the polishing is buffing or buffing after emery polishing.   The hydrogen storage alloy piece (1) outputs a displacement of the free end accompanying hydrogen storage and discharge, with one end serving as a fixed end and the other end serving as a free end. The actuator according to any one of 10.   The actuator according to claim 11, further comprising a reciprocating mechanism for taking out the displacement of the free end of the hydrogen storage alloy piece (1) as a reciprocating movement along one direction.

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