JP2001214851A - Actuator and control method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve an operational characteristic when heating a shape memory alloy by a thermoelectric module. SOLUTION: This actuator is provided with the shape memory alloy 1, the thermoelectric module 4 for heating and cooling the shape memory alloy 1, a bias member 6 for imparting prestrain to the shape memory alloy 1, and a control part for controlling a deformation amount of the shape memory alloy 1 by a current-carrying quantity to the thermoelectric module. A heat sink 5 composed of a heat accumulating material is installed on the other heat exchange surface of the thermoelectric module 1 for heating and cooling the shape memory alloy 1 via a heat equalizing material 3 when one heat exchange surface contacts with the heat equalizing material 3, and the shape memory alloy 1 is heated by a thermal movement from the heat sink 5.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an actuator comprising a shape memory alloy and a thermoelectric module for heating and cooling the same and a method for controlling the actuator.

[0002]

2. Description of the Related Art Various types of actuators utilizing a shape memory alloy, particularly an actuator which obtains a thrust by heating and cooling a shape memory alloy pre-strained by a bias member by a thermoelectric module are provided.

[0003]

However, in the prior art, when heating and cooling by the thermoelectric module, the original heating / cooling capacity (steady capacity) of the thermoelectric module is used. The usage and number of modules had to be increased.

SUMMARY OF THE INVENTION The present invention has been made in view of the foregoing, and an object of the present invention is to improve the operating characteristics of a shape memory alloy having a high heat capacity during heating and cooling by increasing the number of thermoelectric modules. It is an object of the present invention to provide an actuator which can be obtained without any problem and a control method thereof.

[0005]

SUMMARY OF THE INVENTION The present invention provides a shape memory alloy, a thermoelectric module for heating and cooling the shape memory alloy, a bias member for prestraining the shape memory alloy, and a shape memory alloy. A controller for controlling the amount of deformation by the amount of current supplied to the thermoelectric module, wherein one of the heat exchange surfaces contacts the soaking material and heats and cools the shape memory alloy through the soaking material. It is characterized in that a heat sink made of a heat storage material is attached to the other heat exchange surface of the module, and the shape memory alloy is heated by heat transfer from the heat sink.

It is preferable that the heat equalizing material is formed of a flexible material or that a lubricating medium is interposed between the shape memory alloy and the heat equalizing material.

It is desirable that the shape memory alloy is in the form of a flat plate.

[0008] It is also preferable that the contact surface between the shape memory alloy and the soaking material is an uneven surface that fits each other.

[0009] The shape memory alloy may have a corrugated shape or a mesh structure in the direction of expansion and contraction.

The heat equalizing material may be formed in an arc shape, and the shape memory alloy may be disposed along the arc surface of the heat equalizing material. In this case, the shape memory alloy has a plate shape or a direction in which the shape memory alloy expands and contracts. On the other hand, the thermoelectric module may be corrugated or have a mesh structure, and the thermoelectric module may be arranged along the inner circumference of the heat equalizing material, or the heat sink may be arranged inside the heat equalizing material. You may arrange in space.

Further, the present invention provides a shape memory alloy, a thermoelectric module for heating and cooling the shape memory alloy, a bias member for applying a pre-strain to the shape memory alloy, and a deformation amount of the shape memory alloy to the thermoelectric module. An actuator having a control unit that controls the amount of electricity, the other of the thermoelectric module having one heat exchange surface fixed to the shape memory alloy, heating and cooling the shape memory alloy, and moving following the deformation of the shape memory alloy. Another feature is that a heat sink made of a heat storage material is attached to the heat exchange surface, and the shape memory alloy is heated by heat transfer from the heat sink.

In this case, as the shape memory alloy, a coil shape formed of a strip can be suitably used.

The thermoelectric module may be fixed to the shape memory alloy via an intermediate layer for relaxing the stress, or may be fixed on a fixing projection integrally projecting from the shape memory alloy.

[0014] A high thermal conductivity material layer having a thermal conductivity higher than the thermal conductivity of the shape memory alloy is provided on the surface of the shape memory alloy other than the fixing portion of the thermoelectric module. It is also desirable to coat the surface except for the heat insulating material. It is also preferable that the shape memory alloy has a polygonal cross section having a plurality of planes on its outer surface.

When the shape memory alloy is coil-shaped and expands and contracts in the axial direction, the bias portion applies the axial bias force and the torsional bias force to the shape memory alloy. Is also good.

Preferably, the biasing member is formed of an elastic material covering the periphery of the shape memory alloy.

The bias member may be formed of another shape memory alloy and a thermoelectric module for heating and cooling the shape memory alloy.

It is preferable that the heat sink is formed of a heat storage material with a change in latent heat.

Further, as the heat sink, a heat sink having irregularities on a portion other than the fixing surface to the thermoelectric module, a heat sink having a porous shape, a heat sink formed in an arc shape, or the like can be suitably used.

A shape memory alloy is disposed along the outer peripheral surface of a heat equalizing material rotatable around an axis, and one end of the shape memory alloy having one end fixed to the heat equalizing material is fixed via a bias member. It may be.

The two links connected by the shaft may be connected by a shape memory alloy on one side and connected by a bias member on the other side.

In controlling the actuator, the heat exchange surface on the shape memory alloy side of the thermoelectric module is cooled with a current within the maximum current value when the maximum cooling capacity of the thermoelectric module is given, and the maximum current value It is preferable to heat the heat exchange surface on the shape memory alloy side of the thermoelectric module with the above current.

The amount of current supplied to the thermoelectric module can be changed while referring to a preset target current value,
It is also preferable that the preheating up to the control start target temperature of the thermoelectric module at the time of first power-on is performed by temperature feedback control.

[0024]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to an example of an embodiment. In FIG. 1, an output shaft 2 is connected to one end of a shape memory alloy 1 having a coil shape. A thermoelectric module 4 is arranged on the outer periphery of the shape memory alloy 1 via a cylindrical heat equalizing material 3. The thermoelectric module 4 here has a π-type structure in which a p-type thermoelectric element and an n-type thermoelectric element are sequentially connected in series by an electrode plate, and is formed so as to surround the outer periphery of the cylindrical heat equalizing material 3. The heat exchange surface on the inner peripheral side is brought into contact with the outer peripheral surface of the heat equalizing material 3, and the cylindrical heat sink 5 formed of a heat storage material is brought into contact with the heat exchange surface on the outer peripheral side. Further, one end of a bias member 6 composed of a coil spring is fixed to the heat equalizing member 3, and the other end of the bias member 6 is brought into contact with one end of the shape memory alloy 1 on the output shaft 2 side. In the figure, reference numeral 9 denotes a control unit for performing current control.

In this actuator, FIG.
In the state in which the shape memory alloy 1 is contracted, the heat exchange surface on the heat equalizing material 3 side of the thermoelectric module 4 and the heat exchange on the heat sink 5 side are switched by switching the polarity of the power supply supplied to the thermoelectric module 4. If the surface is an endothermic surface, the coil-shaped shape memory alloy 1 is stretched by the shape recovery operation, and
As shown in (b), the output shaft 2 is compressed while the bias member 6 is compressed.
Press in the direction of its axis.

Conversely, when the shape memory alloy 1 is cooled, the rigidity of the shape memory alloy 1 is reduced, and the shape memory alloy 1 is returned to the original state by the elastic force of the bias member 6. A friction medium between the shape memory alloy 1 and the soaking material 3 is reduced by arranging a lubricating medium made of heat conductive grease at a contact portion between the shape memory alloy 1 and the soaking material 3.

Here, one of the heat exchange surfaces is connected to the heat equalizing material 3.
The heat storage material is used as the heat sink 5 as described above as the heat sink 5 that is in contact with the other heat exchange surface of the thermoelectric module 4 that is in contact with the shape memory alloy 1 via the. That is, the heat released from the other heat exchange surface of the thermoelectric module 4 when the heat exchange surface on the shape memory alloy 1 side is cooled is stored in the heat sink 5, and the heat exchange surface on the shape memory alloy 1 side is heated. In this case, the amount of heat stored in the heat sink 5 is moved to the shape memory alloy 1 side, and when the polarity of current supply to the thermoelectric module 4 is switched, the amount of heat stored in the shape memory alloy 1 is changed to the heat storage material. Is moved to the heat sink 5.

In the actuator in which the operating force is generated by heating the shape memory alloy 1, the heat sink 5 made of a heat storage material is disposed on the other heat exchange surface. As compared with the one arranged on the surface, the actuator can respond to the heating of the shape memory alloy 1 having a higher heat capacity and can have an actuator with good responsiveness.

Further, if a heat sink having a latent heat change is used as the heat sink 5 made of a heat storage material, a heat sink 5 having the same heat storage power can be used as compared with the case where a heat sink having no latent heat change is used. The size can be reduced.
In addition, as the heat sink 5 having a latent heat change, a heat sink in which a paraffin is included in a copper container, a heat pipe, or the like can be used.

As the shape memory alloy 1, an alloy (Nitinol) having a mixing ratio of nickel and titanium of about 50:50 and having an austenite phase at a high temperature and a martensite phase at a low temperature can be preferably used. It may be provided with an intermediate phase of high temperature and low temperature by heat treatment, or may be slightly mixed with copper or aluminum, and is not limited to the above.

As the heat equalizing material 3, a rigid material such as aluminum or copper, or a flexible material obtained by mixing carbon or noble metal particles into silicon or silicon rubber is used. By using a cylindrical shape, heat conduction along the shape memory alloy 1 is possible, and a material having a fast thermal response can be obtained. Further, when the soft heat equalizing material 3 is used, the shape of the shape memory alloy 1 can be fitted, so that a high-speed response by high-speed heat transfer can be realized.

When the coil-shaped shape memory alloy 1 is expanded and contracted, the shape memory alloy 1 changes its outer diameter.
May be separated. FIG. 2 addresses this point. The other end of the coil-shaped shape memory alloy 1 having one end fixed thereto and one end of a bias member 6 which is a coil spring are fixed, and the other end of the bias member 6 is connected to a rotating body. The rotating body 60 is fixed to the heat equalizing material 3 by a fixing screw 61.
It can be fixed to. If the rotating body 60 is rotated and fixed with the fixing screw 61, the bias member 6 as a coil spring and the coil-shaped shape memory alloy 1 can be twisted. Can also apply a torsional bias force to the coil-shaped shape memory alloy 1. The diameter change that is about to occur with the expansion and contraction of the shape memory alloy 1 is
Since it is suppressed by the biasing force in the twisting direction, the thermal contact between the heat equalizing material 3 and the shape memory alloy 1 can be favorably maintained.

The present invention is not limited to the shape memory alloy 1 having a coil shape and capable of taking out an output in the axial direction. As shown in FIGS.
Alternatively, a thermoelectric module 4 may be arranged on a flat shape memory alloy 1 with a soaking material 3 interposed therebetween. Also,
When the shape memory alloy 1 is long, a plurality of thermoelectric modules 4 may be arranged on the soaking material 3. Also, here, the shape memory alloy 1 is shown to be elongated in the longitudinal direction during heating and contracted by the force of the bias member 6 during cooling. However, it is needless to say that the shape memory alloy 1 may be stored in a shape-memory manner. The heat storage heat sink 5 may be provided for each thermoelectric module 5 or a heat sink 5 extending over a plurality of thermoelectric modules 1 may be used.

FIG. 5 shows that the uneven surface corresponding to the uneven surface of the shape memory alloy 1 on the side of the heat equalizing material 3 is provided on the heat equalizing material 3 so that the contact area between the shape memory alloy 1 and the heat equalizing material 3 can be reduced. In this case, the heat transfer area can be improved, and thus the response of the shape memory alloy 1 can be improved.

When the shape memory alloy 1 is expanded and contracted in its longitudinal direction, the thrust can be increased by arranging a plurality of shape memory alloys 1 on the heat equalizing plate 3 in parallel. As described above, by making the shape memory alloy 1 into a corrugated shape or as shown in FIG.
The amount of expansion and contraction can be increased. The bias member 6 can be arranged as shown in FIG. 8 with respect to the shape memory alloy 1 which expands and contracts in the longitudinal direction.

FIG. 9 shows the use of a soaking material 3 having an arc-shaped outer surface, and a linear, band-shaped, wavy, or mesh-shaped shape memory alloy 1 disposed along the arc-shaped outer surface. Then, the shape memory alloy 1 expands and contracts along the arc surface of the soaking material 3 by heating and cooling by the thermoelectric module 4 in which one heat exchange surface is brought into contact with the end face of the soaking material 3. Further, FIG. 10 shows that the heat equalizing material 3 is cylindrical, the outer peripheral surface is the surface on which the shape memory alloy 1 is arranged, and a plurality of thermoelectric modules 4 are arranged on the inner peripheral surface at substantially equal intervals in the circumferential direction. Showing things. FIG.
In FIG. 10, the heat sink 5 is fixed to one surface of the thermoelectric module 4, but in the one shown in FIG. 10, the cylindrical heat sink 5 is disposed on the inner peripheral side of the thermoelectric module 4, The entire area on the inner peripheral side may be the heat sink 5. Further, the bias member 6 can be arranged as shown in FIG. 11 with respect to a shape memory alloy that expands and contracts along the outer peripheral surface of the heat equalizing material 3.

The thermoelectric module 4 may be fixed directly to the surface of the shape memory alloy 1. FIG. 12 shows an example of this case, in which a plurality of thermoelectric modules 4 are fixed to the outer peripheral surface (or inner peripheral surface) of a shape memory alloy 1 formed by winding a strip material into a coil shape. I have.
In this case, the distance between the thermoelectric modules 4 changes as the shape memory alloy 1 expands and contracts.
It is provided for each thermoelectric module 1.

As shown in FIG. 13, the thermoelectric module 4 may be fixed to the shape memory alloy 1 via the intermediate layer 45.
The thermoelectric module 4 can be fixed to the outer surface of the shape memory alloy 1 having a round cross section, and the stress applied to the thermoelectric module 4 when the shape memory alloy 1 is deformed can be reduced by the intermediate layer 45. In this case, the soaking material 3
It is preferable to use the same material as described above.

Further, as shown in FIG. 14, a fixing projection 14 is integrally protruded from the coil-shaped shape memory alloy 1 to the outer peripheral side, and the thermoelectric module 4 is fixed on the fixing projection 14. In this case, stress applied to the thermoelectric module 4 when the shape memory alloy 1 is deformed can be reduced.

Even when the thermoelectric module 4 is fixed to the shape memory alloy 1, the shape memory alloy 1 does not have to be coil-shaped. FIG. 15 shows a case where a plurality of thermoelectric modules 4 are fixed on one surface of a strip-shaped shape memory alloy 1 which expands and contracts in the longitudinal direction at intervals. Since the distance between the thermoelectric modules 4 changes with the expansion and contraction of the shape memory alloy 1, a heat sink 5 made of a heat storage material is provided for each thermoelectric module 4.

In the structure shown in FIG. 15, a portion of the surface of the shape memory alloy 1 where the thermoelectric module 4 is not fixed is provided with a high heat having a heat conductivity higher than that of the shape memory alloy 1. The conductivity material layer 16 is provided to prevent a temperature non-uniformity in the shape memory alloy 1 and promote high-speed heat transfer. As the material of the high thermal conductivity material layer 16, the same material as the above-described heat equalizing material 3 can be used. Instead of the high thermal conductivity material layer 16, as shown in FIG. 16, the outer surface of the shape memory alloy 1 except for the fixing portion of the thermoelectric module 4 may be covered with a heat insulating material 17.

The shape memory alloy 1 having a polygonal cross-section having a plurality of flat outer surfaces is preferable from the viewpoint that the bonding strength can be increased, from the viewpoint of fixing the thermoelectric module 4. Is, as shown in FIG.
The thermoelectric module 4 may be fixed to a plurality of outer surfaces.

Note that the thermoelectric module 4
18 can be arranged in the same configuration as that shown in FIG. 1 to FIG. 11, but in addition, as shown in FIG.
Is covered with a bias member 6 made of an elastic material,
If the shape memory alloy 1 and the bias member 6 are integrated, it is advantageous for miniaturization as a whole. This configuration can be applied to a case where the thermoelectric module 4 is not fixed to the shape memory alloy 1.

Further, the bias member 6 may be composed of another shape memory alloy 1 and the thermoelectric module 4.
FIG. 19 shows an example of this case. A pair of shape memory alloys 1 each having a coil shape and a thermoelectric module 4 fixed to the outer surface are arranged in the axial direction, and one of the shape memory alloys 1 is arranged.
Is heated by the thermoelectric module 4, the other shape memory alloy 1 is cooled by the thermoelectric module 4. Each shape memory alloy 1 functions as a bias member 6 for the other shape memory alloy 1 when heated.

The shape memory alloy 1 is different in softness between high temperature and low temperature, and can be softer than a normal bias spring at low temperature. Therefore, the thrust and stroke of the shape memory alloy 1 to be heated are reduced. It can be made large and is advantageous as an actuator. In addition, the configuration using the shape memory alloy 1 as the bias member 6 can also be applied to a configuration in which the thermoelectric module 4 is not fixed to the shape memory alloy 1.

The configuration in which the bias member 6 also applies a torsional bias force to the coil-shaped shape memory alloy 1 can be applied to a structure in which the thermoelectric module 4 is fixed to the shape memory alloy 1.

FIG. 20 shows another example of the heat sink 6, particularly one that can be suitably used for a type in which the thermoelectric module 4 is fixed to the shape memory alloy 1.
FIG. 20 (a) shows a case where irregularities are formed on a surface other than the surface fixed to the thermoelectric module 4, FIG. 20 (b) shows a case where many holes are formed,
FIG. 20 (c) shows an arc shape, and when the shape memory alloy 1 is a coil shape, it can be arranged along the shape memory alloy 1 so that the diameter of the actuator can be reduced when forming a circular cross section actuator. It shows what can be achieved.

FIG. 21 shows an actuator capable of obtaining a rotary motion as an actuator.
The thermoelectric module 4 is fixed to the end surface of the heat equalizing material 3 having a circular cross section which is rotatable around the center, and the other end of the shape memory alloy 1 having one end fixed along the outer peripheral surface of the heat equalizing material 3 is biased. It is fixed to a fixed part via a member 6. When the shape memory alloy 1 expands and contracts due to the heating and cooling of the shape memory alloy 1 by the thermoelectric module 4, since the heat equalizing material 3 rotates around the axis 30, a rotation output can be taken out from the heat equalizing material 3.

FIG. 22 shows a case where a bending type serial link is formed by using a telescopic actuator.
The two links 71 and 72 connected by 0 are connected by a telescopic actuator A on one side, and the other side is connected by a bias member 6. When the shape memory alloy of the actuator A is heated, as shown in FIG.
When the link 72 is tilted and the shape memory alloy is cooled, the link 71 returns by the force of the bias member 6 as shown in FIG.

When energizing the thermoelectric module 4 for heating and cooling the shape memory alloy 1, it is preferable to make the current value different between when the shape memory alloy 1 is heated and when it is cooled. When the current value when the maximum cooling capacity is given to the thermoelectric module 1 is set to the maximum current value, as shown in FIG. 23, when the shape memory alloy 1 is cooled, a current within the maximum current value flows. At the time of heating, a current equal to or more than the above-mentioned maximum current value flows. When a current exceeding the maximum current value is applied during cooling, the cooling capacity is rather reduced, but during heating, the heating heat increases in proportion to the current value, so the heating speed of the shape memory alloy 1 should be increased. Can be.

It is also preferable to make the amount of current supplied to the thermoelectric module 4 variable while referring to a preset target current value. As shown in FIG. 24, the target input power is calculated with reference to the environmental temperature and the shape memory alloy (SMA) temperature, an energization pattern corresponding to the obtained input power is generated, and the energization control according to the energization pattern is performed. Do it. It is possible to control the generation of unnecessary heat energy from the thermoelectric module.

Further, when the power is turned on for the first time,
If the preheating of the thermoelectric element module 4 until the temperature reaches the target temperature T0 at which the control is started is set as feedback control by detecting the current temperature T, it is effective to avoid overshoot that exceeds the target temperature T0.

[0053]

As described above, according to the present invention, a shape memory alloy, a thermoelectric module for heating and cooling the shape memory alloy, a bias member for prestraining the shape memory alloy, and a deformation of the shape memory alloy And a control unit for controlling the amount by the amount of electricity to the thermoelectric module,
A heat sink made of a heat storage material is attached to the other heat exchange surface of the thermoelectric module in which one heat exchange surface contacts the heat equalizing material and heats and cools the shape memory alloy via the heat equalizing material. Is heated by heat transfer from the heat sink, so that the shape memory alloy can be heated or cooled using the amount of heat stored in the heat sink. Even if the heat capacity of the shape memory alloy is high, The operating characteristics can be improved without requiring an increase in the number of thermoelectric modules, and the operation obtained by deformation of the shape memory alloy during heating can be made highly responsive.

If the heat equalizing material is formed of a flexible material,
Contact between the shape memory alloy and the soaking material can be reliably ensured, and a high-speed response by high-speed heat transfer can be obtained.

If a lubricating medium is interposed between the shape memory alloy and the soaking material, friction during operation of the shape memory alloy can be reduced.

When the shape memory alloy is flat, it is easy to secure a contact area (heat transfer area) with the thermoelectric module.
High speed response of shape memory alloy can be expected.

By making the contact surface between the shape memory alloy and the soaking material a concave and convex surface which fits each other, the heat transfer area can be increased, and high speed response of the shape memory alloy can be expected.

The shape memory alloy may have a corrugated shape or a mesh structure in the direction of expansion and contraction. The expansion ratio of the shape memory alloy can be increased.

When the heat equalizing material is formed in an arc shape and the shape memory alloy is disposed along the arc surface of the heat equalizing material, the expansion / contraction rate per volume of the shape memory alloy can be increased. If the shape is a plate, heat transfer efficiency can be improved.If the shape memory alloy is corrugated in the direction of expansion or contraction or has a mesh structure, the expansion ratio of the shape memory alloy can be further increased. Can be higher. In addition, if the thermoelectric module is arranged along the inner circumference of the soaking material, the size can be reduced by using the dead space, and if the heat sink is arranged in the inner space surrounded by the soaking material, the size can be further reduced. Can be achieved.

Also, a shape memory alloy, a thermoelectric module for heating and cooling the shape memory alloy, a bias member for applying a pre-strain to the shape memory alloy, and a deformation amount of the shape memory alloy can be measured by an amount of electricity to the thermoelectric module. And a control unit for controlling the heat exchange surface of the thermoelectric module, wherein one of the heat exchange surfaces is fixed to the shape memory alloy to heat and cool the shape memory alloy and move following the deformation of the shape memory alloy. Even when a heat sink made of a heat storage material is attached to the surface and heating of the shape memory alloy is performed by heat transfer from the heat sink, heating or cooling of the shape memory alloy using the amount of heat stored in the heat sink can be performed. Even if the heat capacity of the shape memory alloy is high, the operating characteristics during heating and cooling can be improved without requiring an increase in the thermoelectric module. And the kill those can be a good operation resulting in deformation during heating of the shape memory alloy responsive.

In this case, it is advantageous to use the shape memory alloy in the form of a coil formed of a band plate in terms of improvement in the amount of expansion and contraction and fixing of the thermoelectric module.

If the thermoelectric module is fixed to the shape memory alloy via an intermediate layer for stress relaxation, breakage of the thermoelectric module due to stress concentration can be avoided. Even if the thermoelectric module is fixed on the fixing projection piece integrally projecting from the shape memory alloy, the breakage of the thermoelectric module due to stress concentration can be avoided.

By providing a high thermal conductivity material layer having a thermal conductivity higher than the thermal conductivity of the shape memory alloy on the surface of the shape memory alloy other than the fixing portion of the thermoelectric module, it is possible to prevent temperature unevenness of the shape memory alloy. And support for high speed heat transfer.

By covering the surface of the shape memory alloy except for the fixing portion of the thermoelectric module with a heat insulating material, unnecessary heat transfer can be prevented and the efficiency can be improved.

It is also preferable that the shape memory alloy has a polygonal cross section having a plurality of planes on its outer surface. The strength of the junction of the thermoelectric module can be increased.

When the shape memory alloy is coil-shaped and expands and contracts in its axial direction, the bias member applies the axial bias force and the torsional bias force to the shape memory alloy. Is also good. It can reduce the diameter change during expansion and contraction of the shape memory alloy,
It is particularly effective for those which need to be brought into contact with the soaking material.

If the bias member is formed of an elastic material covering the periphery of the shape memory alloy, the size can be reduced by integrating the shape memory alloy and the bias member.

The bias member may be formed of another shape memory alloy and a thermoelectric module for heating and cooling the shape memory alloy. Thrust and stroke as an actuator can be increased.

If the heat sink is formed of a heat storage material with a change in latent heat, the size of the heat sink can be reduced.

Further, as the heat sink, a heat sink having irregularities on a portion other than the fixing surface to the thermoelectric module, a heat sink having a porous shape, a heat sink formed in an arc shape, or the like can be suitably used. In particular, in the case where the shape memory alloy is in the form of a coil and the thermoelectric module is fixed to the shape memory alloy, the heat sink can be arranged along the shape memory alloy, which is advantageous in terms of miniaturization.

When a shape memory alloy is arranged along the outer peripheral surface of a heat equalizing material rotatable around an axis and one end of the shape memory alloy is fixed to the heat equalizing material, the other end of the shape memory alloy is fixed via a bias member. The rotational motion output can be taken out.

If the two links connected by a shaft are connected by a shape memory alloy on one side and connected by a bias member on the other side, a bent serial link can be obtained.

In controlling the actuator, the heat exchange surface on the shape memory alloy side of the thermoelectric module is cooled with a current within the maximum current value at the time of providing the maximum cooling capacity of the thermoelectric module. When the heat exchange surface on the shape memory alloy side of the thermoelectric module is heated with the above current, a high-speed heating can be obtained.

By changing the amount of current supplied to the thermoelectric module while referring to a preset target current value, it is possible to suppress and manage the generation of unnecessary heat energy from the thermoelectric module. By performing the preheating up to the control start target temperature by the temperature feedback control, it is possible to avoid overshooting the target temperature during the preheating.

[Brief description of the drawings]

FIG. 1 shows an example of an embodiment of the present invention, in which (a)
(b) is a sectional view.

FIG. 2 is a sectional view of another example.

FIGS. 3A and 3B are cross-sectional views of still another example.

FIG. 4 is a transverse sectional view of the same.

FIG. 5 is a cross-sectional view of another example.

FIG. 6A is a perspective view of another example, and FIG. 6B is an operation explanatory diagram of a shape memory alloy.

FIG. 7A is a perspective view of still another example, and FIG. 7B is an operation explanatory view of a shape memory alloy.

FIG. 8 is an explanatory diagram of an arrangement of a bias member according to the embodiment.

9A, 9B, 9C, and 9D are perspective views of different examples.

FIGS. 10A and 10B are perspective views of still another example.

FIG. 11 is an explanatory diagram of an arrangement of a bias member according to the embodiment.

FIG. 12 is a perspective view of an example of another embodiment.

FIG. 13 shows another example of the above, where (a) is a side view and (b)
Is a sectional view.

14 shows still another example of the above, and (a) and (b) are perspective views. FIG.

FIG. 15 is a sectional view of a different example from the above.

FIG. 16 is a sectional view of still another example of the above.

FIG. 17 is a cutaway perspective view of another example of the above.

FIG. 18 is a perspective view of still another example of the above.

FIG. 19 shows another example, in which (a) and (b) are cross-sectional views.

20 (a), (b) and (c) are perspective views showing other examples of the heat sink.

FIG. 21 is a side view of another example.

FIGS. 22A and 22B are side views of still another example.

FIGS. 23 (a) and 23 (b) are time charts showing current changes during heating and cooling according to the first embodiment.

FIG. 24 is an explanatory diagram of another operation control.

FIG. 25 (a) is a time chart of still another operation control, and FIG. 25 (b) is an explanatory diagram of feedback control.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Shape memory alloy 3 Heat equalizing material 4 Thermoelectric module 5 Heat sink

Continued on the front page (72) Inventor Yukihiko Kitano 1048 Kadoma, Kazuma, Osaka Pref. Matsushita Electric Works Co., Ltd. F-term (reference)

Claims (32)

[Claims] 1. A shape memory alloy, a thermoelectric module for heating and cooling the shape memory alloy, a bias member for applying a pre-strain to the shape memory alloy, and a deformation amount of the shape memory alloy is determined by an amount of electricity supplied to the thermoelectric module. And a control unit for controlling the actuator, wherein one of the heat exchange surfaces is in contact with the heat equalizing material and heats and cools the shape memory alloy through the heat equalizing material. An actuator, wherein a heat sink made of a conductive material is attached, and heating of the shape memory alloy is performed by heat transfer from the heat sink. 2. The actuator according to claim 1, wherein the heat equalizing material is formed of a flexible material. 3. The actuator according to claim 1, wherein a lubricating medium is interposed between the shape memory alloy and the heat equalizing material. 4. The actuator according to claim 1, wherein the shape memory alloy is flat. 5. The actuator according to claim 1, wherein a contact surface between the shape memory alloy and the heat equalizing material is formed as an uneven surface that fits each other. 6. The actuator according to claim 1, wherein the shape memory alloy has a wavy shape in the direction of expansion and contraction. 7. The actuator according to claim 1, wherein the shape memory alloy has a mesh structure. 8. The actuator according to claim 1, wherein the heat equalizing material has an arc shape, and the shape memory alloy is disposed along an arc surface of the heat equalizing material. 9. The actuator according to claim 8, wherein the shape memory alloy has a plate shape. 10. The actuator according to claim 8, wherein the shape memory alloy is corrugated in the direction of expansion and contraction. 11. The actuator according to claim 8, wherein the shape memory alloy has a mesh structure. 12. The actuator according to claim 8, wherein the thermoelectric module is provided along an inner circumference of the heat equalizing material. 13. The actuator according to claim 12, wherein the heat sink is disposed in an inner peripheral space surrounded by the heat equalizing material. 14. A shape memory alloy, a thermoelectric module for heating and cooling the shape memory alloy, a bias member for applying a pre-strain to the shape memory alloy, and a deformation amount of the shape memory alloy is determined by an amount of electricity supplied to the thermoelectric module. And a control unit for controlling the heat exchange surface of the thermoelectric module, wherein one of the heat exchange surfaces is fixed to the shape memory alloy to heat and cool the shape memory alloy and to move following the deformation of the shape memory alloy. An actuator, wherein a heat sink made of a heat storage material is attached to a surface, and heating of the shape memory alloy is performed by heat transfer from the heat sink. 15. The actuator according to claim 14, wherein the shape memory alloy has a coil shape formed of a strip. 16. The actuator according to claim 14, wherein the thermoelectric module is fixed to the shape memory alloy via a stress relaxation intermediate layer. 17. The actuator according to claim 14, wherein the thermoelectric module is fixed on a fixing piece integrally projecting from the shape memory alloy. 18. A high thermal conductivity material layer having a thermal conductivity higher than the thermal conductivity of the shape memory alloy is provided on a surface of the shape memory alloy other than a fixing portion of the thermoelectric module. An actuator as described. 19. The actuator according to claim 14, wherein the surface of the shape memory alloy other than the fixing portion of the thermoelectric module is covered with a heat insulating material. 20. The actuator according to claim 14, wherein the shape memory alloy has a polygonal cross section having a plurality of planes on its outer surface. 21. The shape memory alloy is coil-shaped and expands and contracts in its axial direction, and the bias member applies an axial bias force and a torsional bias force to the shape memory alloy. The actuator according to claim 1 or 14, wherein: 22. The actuator according to claim 1, wherein the bias member is formed of an elastic material covering the periphery of the shape memory alloy. 23. The actuator according to claim 1, wherein the bias member is formed of another shape memory alloy and a thermoelectric module for heating and cooling the shape memory alloy. 24. The heat sink according to claim 1, wherein the heat sink is formed of a heat storage material having a latent heat change.
4. The actuator according to 4. 25. The actuator according to claim 1, wherein the heat sink is formed to have irregularities on a portion other than a surface fixed to the thermoelectric module. 26. The actuator according to claim 1, wherein the heat sink has a porous shape. 27. The actuator according to claim 1, wherein the heat sink is formed in an arc shape. 28. A shape memory alloy is disposed along an outer peripheral surface of a heat equalizing material rotatable around an axis and one end is fixed to the heat equalizing material. The other end of the shape memory alloy is fixed via a bias member. The actuator according to claim 1, wherein 29. The actuator according to claim 1, wherein the two links connected by the shaft are connected by a shape memory alloy on one side and connected by a bias member on the other side. 30. The method for controlling an actuator according to claim 1, wherein the heat exchange surface on the shape memory alloy side of the thermoelectric module has a current within a maximum current value when a maximum cooling capacity of the thermoelectric module is given. A method for controlling an actuator, wherein the heat exchange surface of the thermoelectric module is heated with a current not less than the maximum current value. 31. The method of controlling an actuator according to claim 1, wherein the amount of current supplied to the thermoelectric module is changed with reference to a preset target current value. . 32. The method for controlling an actuator according to claim 1, wherein the preheating of the thermoelectric module to a control start target temperature at the time of initial power-on is performed by temperature feedback control. Control method.