JPH06124631A - Current heating type driving element - Google Patents

Abstract

PURPOSE:To utilize an advantage of a heater system of small electric power consumption and provide a current heating type driving element easy to be manufactured with respect to a shape memory alloy in the driving element for operating the shape memory alloy by current heating. CONSTITUTION:An electric heater unit 2 having flexibility is attached to a shape memory alloy 1. The electric heater unit 2 is such constituted that a conductive wire is formed at the surface of a film-like heat resistant insulating member having flexibility; that a conductive wire is formed on a metal material having flexibility via a film-like heat resistant insulating member having flexibility; that a conductive wire is wound around a metal material having flexibility via an insulating layer; or that a pair of conductive wires are disposed inside of a resin resistor having self-temperature controlling characteristic and mixed with conductive carbon.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a current heating type drive element for operating a shape memory alloy by current heating.

[0002]

2. Description of the Related Art A drive element using a shape memory alloy is often operated by sensing a change in ambient temperature, but when it is operated independently of ambient temperature, it is usually heated and driven by an electric current. In this case, a method in which a current is directly applied to the shape memory alloy itself (hereinafter referred to as a direct energization method) is generally used, but recently, a shape memory alloy wound with a linear heating element has been proposed. (Practical application Sho 63-4817).

[0003]

The conventional direct energization method has a disadvantage that it requires a low-voltage and large-current power source and consumes more power than heating by a heater. On the other hand, a drive element in the form of a linear heating element wrapped around a shape memory alloy consumes less power than the direct current method, and in some cases a commercial power supply can be used as it is.
It is superior to the direct current method, but when the shape of the shape memory alloy is complicated, the manufacturing process for winding the heating element is difficult and the cost is high. In particular, the transformation temperature (martensite transformation temperature) of shape memory alloys that operate by current heating is usually several tens of degrees higher than normal temperature, and since such alloys have relatively low strength at normal temperatures, processing that winds a heating element. Will be even more difficult.

Therefore, an object of the present invention is to provide a current heating type drive element which takes advantage of the heater heating method which consumes less power and which can be easily manufactured and processed for a shape memory alloy.

[0005]

A current heating type drive element according to the present invention has a structure in which a flexible electrothermal type heater unit is mounted on the surface of a shape memory alloy. In this case, the electrothermal heater unit has a structure in which a heater wire is formed on the surface of a flexible film-shaped heat-resistant insulating material, or a flexible film-shaped heater is formed on the surface of a flexible metal material. It has a structure in which a heater wire is formed through a heat-resistant insulating material or a structure in which a heater wire is wound around a flexible metal material through an insulating layer.

Further, in this case, the electrothermal heater unit has a structure in which a pair of heater wires are mounted inside a resistor made of resin in which conductive carbon is mixed, and the resistor responds to temperature changes. It has a self-controlling property in which the resistance value is increased or decreased by expansion and contraction, and the resistance value is increased or decreased by the change in the distance between the particles of the conductive carbon mixed therein.

[0007]

In the structure of the present invention, when the shape memory alloy is heated by passing an electric current through the heater unit, the shape memory alloy operates so as to return to the memorized shape when the temperature reaches or exceeds the transformation point. At this time, since the heater unit is composed of a flexible member, it does not interfere with the operation of the shape memory alloy in accordance with the movement of the shape memory alloy, and always adheres to the shape memory alloy until the operation is completed. Keep heating.

Further, since the heater unit can be manufactured independently of the shape memory alloy, it is much easier to manufacture than the conventional manufacturing process in which the heater wire is directly wound around the shape memory alloy having low strength at room temperature. Easy to attach to shape memory alloy.

Further, when a so-called self-temperature control type heater unit in which a pair of heater wires are mounted inside a resistor made of a resin mixed with conductive carbon is used as the heater unit, it is possible to change the temperature according to the temperature environment. Since it has a self-temperature control function in which the amount of heat generation automatically increases and decreases, it can be used safely without overheating without the need for a temperature control device.

[0010]

FIG. 1 is a constitutional view showing an embodiment of a current heating type drive element according to the present invention, in which a flexible shape is formed on the upper surface of a plate-shaped or strip-shaped shape memory alloy 1 partially bent in an arc shape. The electric heating type heater unit 2 is attached with a heat resistant adhesive. As the shape memory alloy 1, a Ni-Ti based alloy, a Cu-Al-Zn based alloy, or a Cu-Al-Ni based alloy can be used. In Ni-Ti alloys, N
The iTi alloy (binary alloy) and the NiTiCu alloy (ternary alloy) are particularly good driving elements.

FIG. 2 is a constitutional view showing an embodiment of the electrothermal heater unit 2, FIG. 2 (a) is a plan view, and FIG.
It is sectional drawing on the A'line. The heater unit 2 has a heater wire 4 made of a thin wire such as a nichrome wire or a stainless wire on a surface of an insulating material 3 made of a highly flexible heat-resistant film made of a polyimide resin, a Teflon resin or the like and having a required length. It is made up of only heat-resistant resin attached.
As another method for fixing the heater wire 4 to the insulating material 3, two films (insulating material) are used as shown in FIG.
The heater wire 4 may be sandwiched between the films 3, 3'and the films 3, 3'may be bonded together.

FIG. 3 is a constitutional view showing another embodiment of the electrothermal heater unit 2, in which a heater pattern 5 is formed on the surface of an insulating material 3 made of a polyimide resin or Teflon resin film by a method such as sputtering, and both ends are formed. The lead wire 6 is connected to.

In this structure, when the shape memory alloy 1 is heated by passing an electric current through the heater wire 4 or the heater pattern 5 of the electrothermal heater unit 2, the shape memory alloy 1 is shaped when the temperature becomes equal to or higher than the transformation point. Alloy 1 is activated and tries to return to the memory shape. At this time, since the heater unit 2 is flexible, it deforms following the shape memory alloy 1 without hindering the operation of the shape memory alloy 1.

Since this heating method is a heater heating method, the power consumption is smaller than that of the direct energization method. Further, since the heater unit 2 can be manufactured independently, it is much easier to manufacture than when the heater wire is wound around the shape memory alloy 1. Further, since the shape memory alloy 1 is plate-shaped, it is easy to attach the heater unit 2 thereto.

FIG. 4 is a constitutional view showing another embodiment of the current heating type drive element according to the present invention. FIG. 4 (a) shows the state of the shape memory alloy below the transformation point, and FIG. 4 (b) shows the shape memory. The state when the temperature of the alloy is above the transformation point is shown.

In this embodiment, a metal plate having a spring property (flexibility), such as phosphor bronze, having a shape close to the shape of the shape memory alloy 1 below the transformation point is formed on the top surface of the shape memory alloy 1. 7, the above-mentioned electrothermal heater unit 2 is attached to the upper surface of the metal plate 7, and the shape memory alloy 1
Also, one end of the metal plate 7 is fixed to the support member 8 with a fixing screw 9.

In this configuration, the shape memory alloy 1 is relatively soft below the transformation point, so it is bent by being restrained from above by the metal plate 7 (FIG. A), but an electric current is passed through the heater unit 2. When heated to a temperature equal to or higher than the transformation point, it acts to return to the memorized shape, and at the same time, the strength increases, so that the metal plate 7 is deformed to approach the memorized shape (FIG. B).

FIG. 5 is a constitutional view showing another embodiment of the current heating type drive element according to the present invention. FIG. 5A shows a state in which the shape memory alloy is below the transformation point, and FIG. The state when the temperature of the alloy is above the transformation point is shown.

In this embodiment, contrary to the above-mentioned embodiment (FIG. 4), the metal plate 7 is bent so that the shape memory alloy 1 is pulled from below, and the lower surface of the shape memory alloy 1 is springy. The above-mentioned heater unit 2 is attached to the lower surface of the metal plate 7, the one end is fixed to the supporting member 8 with the fixing screw 9, and the other end is fixed with the rivet 10.

Fixing of the shape memory alloy 1 and the metal plate 7 with the rivet 10 requires a structure capable of sliding in the longitudinal direction, but in this embodiment, two plates 1 and 7 are used.
The holes 1a and 7a, which are oval in shape, are drilled in each of the holes and loosely riveted to enable this.

In the configuration of this embodiment, the shape memory alloy 1
Is pulled below the transformation point and bent downward, but when a current is applied to the heater unit 2 to heat it to a temperature above the transformation point, the shape memory alloy 1 resists the metal sheet 7. It deforms so that it approaches the memory shape. In the case of this embodiment, there is an advantage that the shape memory alloy 1 and the metal plate 7 are more closely adhered to each other and the thermal conductivity is more excellent than the above-mentioned embodiment (FIG. 4).

In the above-mentioned embodiment, the heater wire 4 or the heater pattern 5 is formed on the film-shaped insulating material 3, and the insulating material 3 is attached to the shape memory alloy 1 or the metal plate 7. Alternatively, the insulation-coated heater wire may be directly wound around the metal plate 7, and the metal plate 7 may be attached to the shape memory alloy 1. With this configuration, the manufacturing process can be further facilitated, the winding density of the heater wire can be changed depending on the position, and it is possible to prevent local strain from concentrating on the shape memory alloy 1. Also,
Bending deformation tends to cause strain concentration in the bending support portion, but this can be prevented.

FIG. 6 is a constitutional view showing another embodiment of the current heating type drive device according to the present invention, and the portions corresponding to those of the above-mentioned embodiment are designated by the same reference numerals. In this embodiment, a self-temperature control type heater unit 20 as an electrothermal type heater unit is attached to the upper surface of the band-shaped shape memory alloy 1 with a heat resistant adhesive.

The heater unit 20 has a pair of parallel heater wires 4 covered with a resistor 21 having a self-controlling property, as shown in the sectional view of FIG. It has a structure coated with.

The resistor 21 is a mixture of cross-linked fluororesin and conductive carbon. The fluororesin expands and contracts in response to temperature changes, and the distance between dispersed carbon particles changes, resulting in a resistance value. It has the function of increasing and decreasing.

In this structure, when a current is passed between the heater wires 4 of the self-temperature control type heater unit 20, the current flows from one heater wire 4 through the resistor 21 to the other heater wire 4, and the shape memory alloy. Heat 1. Shape memory alloy 1
When the temperature becomes higher than the transformation point, the shape memory alloy 1 operates and tries to return to the memorized shape. At this time, the heater unit 2
Since 0 has flexibility, it deforms following the shape memory alloy 1 without disturbing its operation.

At the same time, the fluororesin of the resistor 21 expands due to heat generation, the distance between the dispersed carbon particles increases, and the resistance value of the resistor 21 increases. As a result, the current flowing between the heater wires 4 is reduced, and the amount of heat generated is also automatically reduced.

As described above, since the heater unit 20 has a self-temperature control function in which the amount of heat generation automatically increases or decreases according to the temperature environment, it can be safely used without overheating without the need for a temperature control device. .

[0029]

According to the present invention, the heater unit as the heating source can be easily attached to the shape memory alloy. In addition, since the heating method is the heater heating method, a low-cost drive element that consumes less power, saves space, and is more reliable than the direct current heating method is put into practical use. If a metal plate is used for the electrothermal heater unit, it can be used as a bias spring for the shape memory alloy, and in this case, there is an advantage that the drive element becomes compact.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an embodiment of a current heating type drive element according to the present invention.

FIG. 2 is a configuration diagram showing an embodiment of the electrothermal heater unit shown in FIG.

FIG. 3 is a configuration diagram showing another embodiment of the electrothermal heater unit shown in FIG.

FIG. 4 is a configuration diagram showing another embodiment of the current heating type drive element according to the present invention.

FIG. 5 is a configuration diagram showing another embodiment of the current heating type drive element according to the present invention.

FIG. 6 is a configuration diagram showing another embodiment of the current heating type drive element according to the present invention.

7 is a sectional view showing an embodiment of the self-temperature control type heater unit shown in FIG.

[Explanation of symbols]

 1 Shape Memory Alloy 2 Electrothermal Heater Unit 3, 3'Insulation Material 4 Heater Wire 5 Heater Pattern 6 Lead Wire 7 Metal Plate 8 Supporting Member 9 Fixing Screw 10 Rivet 20 Self-Temperature Controlled Heater Unit 21 Self-Controlling Resistor 22 Insulation coating

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[Procedure amendment]

[Submission date] August 20, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] Full text

[Correction method] Change

[Correction content]

[Document name] Statement

Title: Current heating type drive element

[Claims]

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a current heating type drive element for operating a shape memory alloy by current heating.

[0002]

2. Description of the Related Art A drive element using a shape memory alloy is often operated by sensing a change in ambient temperature, but when it is operated independently of ambient temperature, it is usually heated and driven by an electric current. In this case, a method in which a current is directly applied to the shape memory alloy itself (hereinafter referred to as a direct energization method) is generally used, but recently, a shape memory alloy wound with a linear heating element has been proposed. (Practical application Sho 63-4817).

[0003]

The conventional direct energization method has a disadvantage that it requires a low-voltage and large-current power source and consumes more power than heating by a heater. On the other hand, a drive element in the form of a linear heating element wrapped around a shape memory alloy consumes less power than the direct current method, and in some cases a commercial power supply can be used as it is.
It is superior to the direct current method, but when the shape of the shape memory alloy is complicated, the manufacturing process for winding the heating element is difficult and the cost is high. In particular, the transformation temperature (martensite transformation temperature) of shape memory alloys that operate by current heating is usually several tens of degrees higher than normal temperature, and since such alloys have relatively low strength at normal temperatures, processing that winds a heating element. Will be even more difficult.

Therefore, an object of the present invention is to provide a current heating type drive element which takes advantage of the heater heating method which consumes less power and which can be easily manufactured and processed for a shape memory alloy.

[0005]

A current heating type drive element according to the present invention has a structure in which a flexible electrothermal type heater unit is mounted on the surface of a shape memory alloy. In this case, the electrothermal heater unit has a structure in which a conductive wire is formed on the surface of a flexible film-shaped heat-resistant insulating material, or a flexible film-shaped heat-resistant material on the surface of a flexible metal material. A conductive wire is formed through a conductive insulating material, or a conductive wire is wound around a flexible metal material through an insulating layer.

Further, in this case, the electrothermal type heater unit has a structure in which a pair of conductive wires is mounted inside a resistor made of a resin in which conductive carbon is mixed, and the resistor is adapted to change in temperature. It has a self-controlling property in which the resistance value is expanded and contracted, and the resistance value is increased or decreased according to the change in the distance between the particles of the conductive carbon mixed therein.

[0007]

In the structure of the present invention, when the shape memory alloy is heated by passing an electric current through the heater unit, the shape memory alloy operates so as to return to the memorized shape when the temperature reaches or exceeds the transformation point. At this time, since the heater unit is composed of a flexible member, it does not interfere with the operation of the shape memory alloy in accordance with the movement of the shape memory alloy, and always adheres to the shape memory alloy until the operation is completed. Keep heating.

Further, since the heater unit can be manufactured independently of the shape memory alloy, it is much easier to manufacture than the conventional manufacturing process in which the conductive wire is directly wound around the shape memory alloy having a low strength at room temperature, and the shape is improved. Easy to attach to memory alloy.

Further, when a so-called self-temperature control type heater unit in which a pair of conductive wires is mounted inside a resin resistor containing a mixture of conductive carbon is used as the heater unit, heat is generated according to the temperature environment. Since it has a self-temperature control function in which the amount automatically increases and decreases, it can be safely used without overheating without the need for a temperature control device.

[0010]

FIG. 1 is a constitutional view showing an embodiment of a current heating type drive element according to the present invention, in which a flexible shape is formed on the upper surface of a plate-shaped or strip-shaped shape memory alloy 1 partially bent in an arc shape. The electric heating type heater unit 2 is attached with a heat resistant adhesive. As the shape memory alloy 1, a Ni-Ti based alloy, a Cu-Al-Zn based alloy, or a Cu-Al-Ni based alloy can be used. In Ni-Ti alloys, N
The iTi alloy (binary alloy) and the NiTiCu alloy (ternary alloy) are particularly good driving elements.

2A and 2B are structural views showing an embodiment of the electrothermal type heater unit 2. FIG. 2A is a plan view and FIG. 2B is a sectional view taken along the line AA '. The heater unit 2 has a conductor 4 made of a thin wire such as a nichrome wire or a stainless wire on the surface of an insulating material 3 made of a highly flexible heat-resistant film made of polyimide resin, Teflon resin or the like and having a required length. It is constructed by sticking only a heat resistant resin.
As a method of fixing the conductor wire 4 to the insulating material 3, other than this, as shown in FIG. 3C, two films (insulating material) 3,
The conductors 4 may be sandwiched between 3'and the films 3, 3'may be bonded together.

FIG. 3 is a constitutional view showing another embodiment of the electrothermal heater unit 2, in which a heater pattern 5 is formed on the surface of an insulating material 3 made of a polyimide resin or Teflon resin film by a method such as sputtering, and both ends are formed. The lead wire 6 is connected to.

In this structure, when the shape memory alloy 1 is heated by passing an electric current through the conductor wire 4 or the heater pattern 5 of the electrothermal heater unit 2, the shape memory alloy 1 is heated when the temperature of the shape memory alloy 1 reaches the transformation point or higher. 1 operates and tries to return to the memory shape. At this time, since the heater unit 2 is flexible, it deforms following the shape memory alloy 1 without hindering the operation of the shape memory alloy 1.

Since this heating method is a heater heating method, the power consumption is smaller than that of the direct energization method. Further, since the heater unit 2 can be manufactured independently, it is much easier to manufacture than when the conductor wire is wound around the shape memory alloy 1. Further, since the shape memory alloy 1 is plate-shaped, it is easy to attach the heater unit 2 thereto.

FIG. 4 is a constitutional view showing another embodiment of the current heating type drive element according to the present invention. FIG. 4A shows a state in which the shape memory alloy is below the transformation point, and FIG. The state when the temperature of the alloy is above the transformation point is shown.

In this embodiment, a metal plate having a spring property (flexibility), such as phosphor bronze, having a shape close to the shape of the shape memory alloy 1 below the transformation point is formed on the top surface of the shape memory alloy 1. 7, the above-mentioned electrothermal heater unit 2 is attached to the upper surface of the metal plate 7, and the shape memory alloy 1
Also, one end of the metal plate 7 is fixed to the support member 8 with a fixing screw 9.

In this configuration, the shape memory alloy 1 is relatively soft below the transformation point, so it is bent by being restrained from above by the metal plate 7 (FIG. A), but an electric current is passed through the heater unit 2. When heated to a temperature equal to or higher than the transformation point, it acts to return to the memorized shape, and at the same time, the strength increases, so that the metal plate 7 is deformed to approach the memorized shape (FIG. B).

FIG. 5 is a constitutional view showing another embodiment of the current heating type drive element according to the present invention. FIG. 5A shows a state in which the shape memory alloy is below the transformation point, and FIG. The state when the temperature of the alloy is above the transformation point is shown.

In this embodiment, contrary to the above-mentioned embodiment (FIG. 4), the metal plate 7 is bent so that the shape memory alloy 1 is pulled from below, and the lower surface of the shape memory alloy 1 is springy. The above-mentioned heater unit 2 is attached to the lower surface of the metal plate 7, the one end is fixed to the supporting member 8 with the fixing screw 9, and the other end is fixed with the rivet 10.

Fixing of the shape memory alloy 1 and the metal plate 7 with the rivet 10 requires a structure capable of sliding in the longitudinal direction, but in this embodiment, two plates 1 and 7 are used.
The holes 1a and 7a, which are oval in shape, are drilled in each of the holes and loosely riveted to enable this.

In the configuration of this embodiment, the shape memory alloy 1
Is pulled below the transformation point and bent downward, but when a current is applied to the heater unit 2 to heat it to a temperature above the transformation point, the shape memory alloy 1 resists the metal sheet 7. It deforms so that it approaches the memory shape. In the case of this embodiment, there is an advantage that the shape memory alloy 1 and the metal plate 7 are more closely adhered to each other and the thermal conductivity is more excellent than the above-mentioned embodiment (FIG. 4).

In the above-described embodiment, the conductor wire 4 or the heater pattern 5 is formed on the film-shaped insulating material 3 and the insulating material 3 is attached to the shape memory alloy 1 or the metal plate 7. It is also possible to wind the insulating-coated conductive wire directly on the metal plate 7 and attach the metal plate 7 to the shape memory alloy 1. According to this structure, the manufacturing process can be further facilitated, and the winding density of the conductive wire can be changed depending on the position, so that local strain can be prevented from concentrating on the shape memory alloy 1. Further, in bending deformation, strain concentration is likely to occur in the bending support portion, but this can be prevented.

FIG. 6 is a constitutional view showing another embodiment of the current heating type drive device according to the present invention, and the portions corresponding to those of the above-mentioned embodiment are designated by the same reference numerals. In this embodiment, a self-temperature control type heater unit 20 as an electrothermal type heater unit is attached to the upper surface of the band-shaped shape memory alloy 1 with a heat resistant adhesive.

In the heater unit 20, as shown in the sectional view of FIG. 7, a pair of parallel conductive wires 4 are covered with a resistor 21 having self-controllability, and the outer periphery of the resistor 21 is covered with an insulating coating 22. It has a coated configuration.

The resistor 21 is a mixture of cross-linked fluororesin and conductive carbon. The fluororesin expands and contracts in response to temperature changes, and the distance between dispersed carbon particles changes, resulting in a resistance value. It has the function of increasing and decreasing.

In this structure, when an electric current is passed between the conductors 4 of the self-temperature control type heater unit 20, the electric current is reduced to one side.
The shape-memory alloy 1 is heated by flowing from the conductive wire 4 through the resistor 21 to the other conductive wire 4. When the temperature of the shape memory alloy 1 becomes equal to or higher than the transformation point, the shape memory alloy 1 operates and tries to return to the memorized shape. At this time, since the heater unit 20 has flexibility, it deforms following the shape memory alloy 1 without hindering the operation of the shape memory alloy 1.

At the same time, the fluororesin of the resistor 21 expands due to heat generation, the distance between the dispersed carbon particles increases, and the resistance value of the resistor 21 increases. As a result, the current flowing between the conductors 4 is reduced, and the amount of heat generated is also automatically reduced.

As described above, since the heater unit 20 has a self-temperature control function in which the amount of heat generation automatically increases or decreases according to the temperature environment, it can be safely used without overheating without the need for a temperature control device. .

[0029]

According to the present invention, the heater unit as the heating source can be easily attached to the shape memory alloy. In addition, since the heating method is the heater heating method, a low-cost drive element that consumes less power, saves space, and is more reliable than the direct current heating method is put into practical use. If a metal plate is used for the electrothermal heater unit, it can be used as a bias spring for the shape memory alloy, and in this case, there is an advantage that the drive element becomes compact.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an embodiment of a current heating type drive element according to the present invention.

FIG. 2 is a configuration diagram showing an embodiment of the electrothermal heater unit shown in FIG.

FIG. 3 is a configuration diagram showing another embodiment of the electrothermal heater unit shown in FIG.

FIG. 4 is a configuration diagram showing another embodiment of the current heating type drive element according to the present invention.

FIG. 5 is a configuration diagram showing another embodiment of the current heating type drive element according to the present invention.

FIG. 6 is a configuration diagram showing another embodiment of the current heating type drive element according to the present invention.

7 is a sectional view showing an embodiment of the self-temperature control type heater unit shown in FIG.

[Explanation of reference numerals] 1 shape memory alloy 2 electric heating type heater unit 3, 3'insulating material 4 conducting wire 5 heater pattern 6 lead wire 7 metal plate 8 supporting member 9 fixing screw 10 rivet 20 self-temperature control type heater unit 21 self-controllability 22 Insulating coating

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hideo Obata 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd.

Claims (5)

[Claims] 1. A current heating type drive element, characterized in that a flexible electrothermal heater unit is mounted on the surface of a shape memory alloy. 2. The current heating type drive element according to claim 1, wherein the electrothermal heater unit is formed by forming a heater wire on a surface of a flexible film-shaped heat-resistant insulating material. . 3. The electrothermal heater unit according to claim 1, wherein a heater wire is formed on a surface of a flexible metal material via a flexible film-shaped heat-resistant insulating material. A current heating type drive element characterized by the above. 4. The current heating type drive element according to claim 1, wherein the electrothermal heater unit is formed by winding a heater wire around a flexible metal material with an insulating layer interposed therebetween. 5. The electrothermal heater unit according to claim 1, wherein a pair of heater wires are mounted inside a resistor made of resin in which conductive carbon is mixed, and the resistor is a temperature sensor. A current heating type drive characterized in that it is a resistor having a self-controlling property that expands and contracts according to a change and the resistance value increases and decreases according to a change in the distance between the particles of the conductive carbon mixed in the inside. element.