JPS60195386A - Shape memory actuator - Google Patents

Abstract

PURPOSE:To eliminate the need for using current adjusting means and simplify construction by forming a layer of electricity insulating body on the surface of a shape memory alloy, and forming a layer of heating resistor on the surface of said electricity insulating body layer, and enabling a resiting value to be maintained constant even when said allow is displaced. CONSTITUTION:As a means of applying heat, a layer of heating resistor 4 is formed through a layer of electricity insulating body 3, on one side surface of a board like shape memory alloy 2. This heating resistor layer 4 is formed with a thin film resistor and is constructed to be bent with respect to the mechanical displacement of the shape memory actuator 1. Even if the shape memory alloy 2 is subjected to plastic deformation by applying external force through a loading spring 5 on the end of the alloy 2 at normal temperatures, it will be restored again to its initial linear state by electrifying and controlling the layer of heating resistor 4 formed on the surface of the alloy 2 by a heating and controlling means 6 containing electric source of heater. Due to this construction, even if the shape memory alloy 2 is displaced accompanying the restoration of its shape, the resistance value for determining the generation of heat for the alloy 2 is constantly maintained, enabling a currnt adjusting means to be eliminated, to simplify construction.

Description

[Detailed description of the invention] [Technical field to which the invention pertains] The invention relates to shape memory actuators.

[Technological environment]

In recent years, the development of devices that utilize the thermo-mechanical energy conversion function due to the shape memory effect of shape memory alloys has been attracting attention.

Various types of shape memory alloys are known, and a typical shape memory alloy is one. The shape memory effect of this unidirectional shape memory alloy is known as a phenomenon in which even if the shape memorized in the high temperature phase is changed at room temperature, the shape returns to the original shape in the high temperature phase upon heating.

[Prior art]

Conventional shape memory actuators are composed of a single shape memory alloy that has shape memory. Such conventional shape memory actuators include those of an indirect drive type in which the actuator is heated indirectly with a heating means, and those of a direct drive type in which the actuator is heated in contact with the heating means.

A conventional shape-memory actuator using an indirect drive method is a type in which the shape-memory alloy itself is exposed to a so-called thermal atmosphere at a temperature higher than the shape-memory setting temperature to return to its original shape.

Therefore, this type of shape memory actuator receives the heat required for shape recovery indirectly.

The drawback was that the heat receiving efficiency was poor. 'f, This type of shape memory actuator has the disadvantage that direct drive control is not possible, and its application has been encouraged. Conventional shape memory actuators using a direct drive method eliminate the above-mentioned disadvantages, and shape memory Alloy KT [The alloy is electrically connected to heat the alloy and driven in M contact.] That is, since the shape memory alloy has an electric resistance specific to the alloy, by directly applying current to cause a thermo-mechanical energy conversion in the shape memory alloy, it is used as an actuator. The shape recovery power of the shape memory alloy of this type of shape memory actuator is heated @A degree.

Since the change depends on the heating rate, shape memory actuators are known in which the sufficient displacement is set by fully energized heating control of the shape memory alloy.However, in the conventional shape memory actuator mentioned above, the drive control section uses shape memory. Since it is an alloy itself, the resistance value, which is a physical property of the shape memory alloy, changes due to the deformation that occurs when the shape memory alloy recovers its shape. Detects changes in the resistance value of the shape memory alloy! This method has the drawback of requiring means for adjusting the current value.

[Purpose of the invention]

The object of the invention is to form an electrical insulator layer on the surface of a shape memory alloy, and to form a resistance heating layer on the surface of the electrical insulator layer, so that the shape memory alloy is displaced as it recovers its shape. Also, the resistance value that determines the heat generation of the shape memory alloy is a single value, and the configuration is simplified by omitting the means to detect all changes in the resistance value of the shape memory alloy and adjust the current value passed through the shape memory alloy. The purpose of the present invention is to provide a shape memory actuator that can

[Structure of the invention]

The uninvented shape memory actuator includes a shape memory alloy,
an electrical insulator layer formed on the surface of the shape memory alloy;
and a resistance heating element layer formed on the surface of the electric chimney body.

[Explanation of Examples]

Next, embodiments of the invention will be described in detail with reference to the drawings.

Figure 1 is a cross-sectional view of the first embodiment of the present invention.

The shape memory actuator shown in FIG. 1 is a resistance heating element 1 in which a resistance heating element layer 4 is formed on one surface of a plate-shaped shape memory alloy 2 through an electric insulator layer 3 as a means for applying heat. Depending on the shape of 2, it is formed on a part of the surface or the entire surface.

Note that the shape of the shape memory alloy 2 is not limited to a plate shape, and various shapes such as a rod shape and a pipe shape can be used depending on the intended use of the actuator. There are various compositions of the shape memory alloy 2, and specifically, as an example, Cu-based alloys such as -rqt-N+ alloy and eu-Zn-A1 alloy may be used.

The resistance heating element layer 4 formed on the surface of the electric insulator layer 3 is formed using a thin film resistor so as to be bent in response to mechanical displacement of the shape memory actuator. Even if the gas insulating layer 3 and the resistance heating layer 4 formed on the surface of the shape memory alloy 2 are formed before the shape memory alloy 2 undergoes martensitic transformation and memorizes the shape, the shape is memorized and set. It may be formed after The resistance value of the resistance heating element layer 4 can be set arbitrarily.

- FIG. 2 is a sectional view showing a second embodiment of the invention.

The shape memory actuator shown in FIG. 2 has a resistance heating layer 4 formed on both the front and back surfaces of a plate-shaped shape memory alloy 2 via an electrical insulating layer 3.Detailed explanation can be found in the embodiment shown in FIG. Since this is basically the same as the related explanation, it will be omitted.

Next, the basic operation of the shape memory actuator shown in FIGS. 1 and 2 will be explained in detail.

After supporting the shape memory actuator shown in FIG. 1 in the form of a cantilever in which the shape memory actuator shown in FIG. Even if the shape memory alloy 2 is subjected to plastic deformation, the resistance heating layer 4 formed on the surface of the shape memory alloy 2 is energized by the heating control means 6 including a heating power source, so that the shape memory returns to its initial linear shape. FIG. 3 is an operation state diagram for explaining the basic operation of the actuator.

As shown in FIG. 3, a linear shape memory actuator is supported in a cantilevered manner, and an external force is applied to the tip by a load spring 5 at room temperature to cause plastic deformation. Load spring 5
guide machine II so that it can move horizontally in the length direction A of dyeing.
Connected to IJ7. In this state, the heating control means 6
In this case, no current is applied to the resistance heating element layer 4 formed by trapping the surface of the shape memory alloy 2.

Now, as shown in FIG. 3(b), the shape memory actuator that has been artificially plastically deformed is connected to a heating power source Kanakura in the resistance heating layer 4, and the heating control means 6 controls the current supply, so that the shape memory actuator becomes @3. It recovers to the shape of the high temperature phase shown in Figure (b), that is, the straight shape. Resistance heating element layer 4
When the resistance value is 1 kR and the total current value of the tail flow source of the external heating control means 6 is i, the maximum heating temperature determined by 12B is reached.

By setting the maximum heating temperature in the heating-cooling cycle total heating control means 6 so as to heat the shape memory alloy 2 to a temperature higher than the transformation temperature, the shape memory actuator 1 is heated as shown in FIG.
The shape shown in Figure 3 (I) repeats the shape shown in a + and Figure 3 (b), and since the recovery force associated with the shape memory of shape memory alloy 2 changes depending on the heating temperature and heating rate, it is shown in Figure 3 (I). When the duty of the energization time and non-energization time is arbitrarily set by the heating control means 6, current is applied to the resistance heating layer 4 in a pulsed manner.

The displacement of the tip of the cantilever dyeing can be set depending on the set current value and the maximum heating temperature determined by the current heating cycle.

That is, the displacement of the shape memory actuator is controlled by setting the magnitude of the current applied to the resistance heating layer 4 of the uninvented shape memory actuator and the current application cycle, and controlling the maximum heating temperature of the shape memory alloy 2. can do. Furthermore, since the resistance value of the resistance heating element layer 4 for controlling the heating of the shape memory alloy 2 of the shape memory actuator of the present invention does not depend on the physical property values of the shape memory alloy 2, when fine-grained position control is performed, the conventional shape There is no need to consider the change in resistance value due to displacement of the shape memory alloy as seen in the memory actuator trap.

That is, there is no need for means for detecting changes in the resistance value of the shape memory alloy.

Next, a specific application example of the inventive shape memory actuator will be explained.

FIG. 4 is a conceptual diagram of an additive type shape memory actuator using the shape memory actuators 1', 1'' shown in FIGS. 1 and 2.

The shape memory actuators 1' and 1'' are both set to memorize a straight line state.Now, at room temperature, the shape memory actuators 1/, 1//Y are configured with the load spring 5 so as to bend into an arcuate shape, and the shape memory actuators 1/, 1//Y are set to be plastic. Transform.

One end of the shape memory actuator 1' is connected to the fixed wall 8, and the other end is connected to the shape memory actuator i"tc by an intermediate rod 9. Furthermore, a tip rod lO is connected to one side of the shape memory actuator 1". It is connected.

The guides 11 and 12 each have an intermediate rod 9. It is configured to guide the tip rod 10 in the horizontal direction BK.

Now, using the heating control means 6, the shape memory actuator 1',
When the resistive heat generating layer formed on the surface of the shape memory actuators 1' and 1'' is heated by electricity, the shape memory actuators 1' and 1'' return to their original straight state. Thus, by controlling the energization heating control means 6, the tip 13 of the tip 10 connected to the shape memory actuator 1'' can be moved additively.

Now, the shape memory actuator 1 is controlled by the heating control means 6.
' and shape memory actuator 1' If heating is controlled for all at the same time or only one of them, the tip rod 1
The displacement of the tip 13 of the 0 can be changed. Therefore, the displacement of the tip of the tip rod can be controlled not only by connecting two shape memory actuators but also by connecting more shape memory actuators by intermediate rods and selectively heating and energizing them using the heating control means. It is possible to create an additive shape memory actuator that can be set arbitrarily.

Above, we have explained in detail the embodiments of non-invention.
The present invention is not limited to the embodiments of the present invention, and various modifications can be made without departing from the gist of the present invention. It will be done.

〔Effect of the invention〕

In the shape memory actuator of the present invention, instead of applying electricity to the shape memory alloy itself, by adding a resistance heating element layer to the surface of the shape memory alloy via an electrical insulator layer, it is possible to apply electricity to the resistance heating element layer. Since the resistance value can be maintained constant even if the shape memory alloy is displaced, changes in the resistance value of the shape memory alloy can be detected.

Electric fi for adjusting the current value passed through the shape memory alloy
! ! Since the i-clause means can be omitted, there is an effect that the configuration can be simplified.

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional view showing the complete embodiment of uninvented @1, Fig. 2 is a sectional view showing the second embodiment of uninvented, Fig. 3 tab (
bl is an operation state diagram for explaining the operation of the shape memory actuator shown in FIG. 1, and FIG. 4 is a conceptual diagram showing an example of application of the shape memory actuator shown in FIGS. 1 and 2. 1.1', 1"...shape memory actuator. 2...shape memory alloy, 3...electric insulator layer, 4...resistance heating element layer, 5... ...Load spring%
6... Heating control means, 7... Guide mechanism,
8...Fixed wall, 9...Intermediate rod, 1
0...Tip rod, 11.12...
・Guide, 13... Tip, A... Length direction of Sakae, B... Horizontal direction.

Claims (1)

[Claims] A shape memory actuator comprising a shape memory alloy, an electric insulator layer formed on the surface of the shape memory alloy, a resistance heating layer formed on the surface of the electric insulator layer, and gold.