WO2002098618A1

WO2002098618A1 - Working mechanism using shape memory alloy

Info

Publication number: WO2002098618A1
Application number: PCT/JP2002/002715
Authority: WO
Inventors: Hitoshi Yoshida
Original assignee: National Institute Of Advanced Industrial Science And Technology
Priority date: 2001-06-01
Filing date: 2002-03-20
Publication date: 2002-12-12
Also published as: JP2002369561A

Abstract

A working mechanism using a shape memory alloy comprises a working structure unit composed of a shape memory alloy and an electric resistor for heating the alloy, a sensor unit composed of means for detecting a change in the environment of the working structure unit, a control unit composed of a computer, and a relay unit composed of a relay. The working mechanism is characterized in that if an change in the environment of the working structure unit occurs, the sensor unit detects the change and converts the change into an electric signal, the control unit receives the electric signal, the relay unit operates in response to a transmission signal from the control unit, the electric resistor of the working structure unit generates heat, the shape memory alloy is heated by the heat generation, and thus the shape memory alloy carries out a memorized action.

Description

Specification

Actuation mechanism using shape memory alloy.

The present invention relates to an operation mechanism using a shape memory alloy. Background art

As seen in a robot or the like, an operation mechanism for performing a predetermined mechanical movement (operation) in accordance with a change in the surrounding environment is known.

However, the mechanical movement by the conventional operation mechanism uses a micromotor and a number of gears interlocked with the micromotor, so that the structure is complicated and the cost is high.

An object of the present invention is to provide a low-cost operating mechanism having a simple structure. Disclosure of the invention

The present inventors have conducted intensive studies to solve the above-mentioned problems, and as a result, have completed the present invention.

That is, according to the present invention, the following operating mechanism is provided.

(1) An operating structure portion, a sensor portion, a control portion, and a relay portion. The operating structure portion includes a shape memory alloy and an electric resistor for heating the alloy. A part is constituted by means for detecting a change in the surrounding environment of the actuation structure, the control unit is constituted by a computer, and the relay unit is an actuation mechanism constituted by a relay. When a change occurs in the surrounding environment of the body, this change is detected by a part of the sensor and converted into an electric signal, and the electric signal is received by the control unit and transmitted from the control unit. Operating the relay section based on the signal to generate heat in the electrical resistor of the operating structure section, heating the shape memory alloy by the generated heat, and performing an operation previously stored in the shape memory alloy. Shape memory alloy characterized by Actuating mechanism was used. (2) The mechanism according to (1), wherein the sensor section is disposed on the operating structure section.

(3) The actuating structure comprises a semicircular ring-shaped body that changes its shape by heating, and the ring-shaped body is

(i) having a shape memory alloy along the circumferential direction of the ring,

(ii) the radius of curvature of the shape memory alloy is reduced or increased by heating;

(iii) having an electrical resistor for heating the alloy;

The operation mechanism according to any one of the above (1) to (2), characterized in that: BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a schematic explanatory view of the operation mechanism of the present invention.

FIG. 2 shows an explanatory view of one embodiment of the working structure used in the present invention. FIG. 2 (a) shows an overall explanatory view.

FIG. 2B is an explanatory sectional view of the ring R. BEST MODE FOR CARRYING OUT THE INVENTION

The actuation mechanism of the present invention has an actuation structure. In the case of the present invention, the actuating structure comprises a shape memory alloy and an electric resistor for heating the shape memory alloy. When the electric resistor is energized to generate heat, the shape memory alloy is heated and Perform the memorized exercise (motion). The motion of the shape memory alloy in this case includes elongation, shortening, bending, and motion for increasing or decreasing the radius of curvature.

The shape of the shape memory alloy may be any appropriate shape according to the movement to be stored in the shape memory alloy, and includes a linear shape, a band shape, a ring shape, a rod shape, a plate shape and the like.

Various types of conventionally known shape memory alloys, for example, Ti-Ni alloy and the like are used. As such a shape memory alloy, an appropriate one is selected according to the movement to be stored therein, the temperature at which the movement is started, and the like.

It is preferable that the shape memory alloy is used by being supported by an elastic body. In this case, panel, steel, plastic, FRP, or the like is used as the elastic support. As the electric resistor, a conventionally known one such as a nickel-chromium alloy is used. The shape can be various shapes such as a linear shape and a narrow band shape. This electric resistor is wound at a position where the shape memory alloy can be heated, usually in a spiral shape around the shape memory alloy, or disposed adjacent thereto.

The operating mechanism of the present invention has a sensor unit. The sensor unit is configured to detect a change as an electric signal when a change occurs in the surrounding environment of the operation structure. Various changes in the surrounding environment of the operating structure include changes in the atmosphere and atmosphere such as temperature, humidity, and pressure, as well as changes in the distance of the object to the operating structure, such as the operating structure. Change in the distance between the pole and the working part when the player grips the ball, and the distance between the working structure and the object when the working structure pushes the approaching object back in the opposite direction And the like.

The sensor used in the sensor section only needs to detect a change in the surrounding environment of the operation structure section, and a conventionally known sensor can be used. For example, when the operating structure performs a certain operation (elongation, shortening, bending, etc.) in response to the ambient temperature, a temperature detector such as a thermistor is used, and an object is moved to the operating structure. When a certain distance is approached and a certain operation is performed in response to its presence, a photoelectric sensor that detects the presence of the object is used.

The sensor may be disposed at any position that can detect a change in the surrounding environment of the operating structure. In the case of the present invention, the operating structure is in contact with the surrounding environment. It is preferred to be located on the surface of the.

The operating mechanism of the present invention has a control unit. This control unit can be a computer, for example, a PLC (programmable controller) or the like.

The control unit operates using an electric signal from the sensor unit as an input signal, and transmits a pre-programmed electric signal as an output signal based on the input signal. The output signal includes a signal for applying a voltage to the electric resistor in the operation structure, a signal indicating a time for applying the voltage, and the like.

The operating mechanism of the present invention has a relay section. This relay section is composed of relays. The relay unit operates based on an electric signal from the control unit, and applies a voltage of a predetermined potential to an electric resistor provided in the operation structure unit for a predetermined time. It has a function to add.

FIG. 1 shows a schematic view of one embodiment of the operating mechanism of the present invention.

In FIG. 1, 1 indicates a control unit, 2 indicates a relay unit, 3 indicates an operation structure unit, and 4 indicates a sensor unit.

In FIG. 1, when a change in the surrounding environment of the operating structure 3 (for example, detection of an article) is detected in the sensor unit (for example, a photoelectric sensor) 4, an electric signal is transmitted from the sensor part 4. You. This signal is sent to the control unit (for example, PLC, etc.) 1 via line 5. The control unit 1 that has received this signal transmits a pre-programmed signal based on the signal. This signal is sent to the relay section 2 via the line 6, and the relay section 2 is operated for a predetermined time and then stopped. By the operation of the relay section 2, a predetermined voltage is applied to the operation structure section 3 via the line 7 for a predetermined time. When the predetermined voltage is applied for a predetermined time, the electric resistor of the operating structure 3 generates a predetermined amount of heat, and the heat is generated, thereby heating the shape memory alloy of the operating structure 3. The heating causes the shape memory alloy to perform a predetermined motion stored in the shape memory alloy.

Next, an example of an operation structure constituting the operation structure used in the present invention will be described with reference to the drawings.

FIG. 2 shows an explanatory view of the operation structure.

FIG. 2 (a) shows a general explanatory view of the working structure.

In this figure, R indicates a semicircular ring, S indicates a sensor (photoelectric sensor), T indicates a support rod, and B indicates a ball. 21 denotes an electric wire connected to the sensor S, and 22 denotes an electric wire connected to the heating wire U.

FIG. 2 (b) shows an explanatory sectional view of the semicircular ring R.

In this figure, 11 is a shape memory alloy (strip, linear, etc.), 12 is an elastic body (strip, linear, etc.), 13 is a molding material, and U is spirally wound on the shape memory alloy. Indicates heating wire.

In FIG. 2 (b), the cross-sectional shape of the ring R is shown as a rectangle, but may be another shape, for example, a circular shape or another polygonal shape.

The semicircular ring R shown in Fig. 2 has a shape memory with a certain radius of curvature a. Combining alloy 11 with a band-shaped elastic body (elastic body such as panel, steel, plastic, FRP, etc.) 12 processed to another radius of curvature b It is integrated (composite). In this case, the molding material 13 is not necessarily required, and can be integrated by an elastic body. This ring can be designed, for example, to have a radius of curvature a 'when heated (high temperature) and a radius b' when cold (unheated).

As a shape memory alloy, a Ti-Ni alloy is usually used, but any alloy having shape memory and having a difference in elastic modulus between a low temperature and a high temperature (tiling) may be used. . -If the radius of curvature a, _a ', b, b' is designed so that a> a '>b'> b, the radius of the ring R becomes large at high temperature and the radius of curvature at high temperature a ′, a ring (tiling) with a radius of curvature b ′ at low temperatures.

On the other hand, if the radius of curvature a, a ', b, b' is designed so that b> b,> a '> a, the radius of the ring R becomes large at low temperatures and the radius of curvature b ', The radius decreases when heated, resulting in a ring (tiling) with a radius of curvature a'.

In order to heat the ring R, as shown in Fig. 2 (b), a heating wire (electric resistance body such as a nichrome wire) is spirally wound around or near the shape memory alloy 11 of the ring R. Should be placed at

A ring R designed to have a large radius at high temperature has a large radius when the heating wire U is energized and the shape memory alloy 11 in the ring is heated above its phase transformation point temperature. Become.

On the other hand, a ring R designed to have a smaller radius at high temperatures, when a current is applied to the heating wire U and the shaped alloy 11 in the ring is heated to a temperature equal to or higher than its phase transformation point, the radius becomes larger. Becomes smaller.

By designing the semi-circular ring R shown in Fig. 2 so that its radius is reduced by heating, it is possible to grasp an article that has entered the semi-circular ring.For example, in Fig. 2 (a) , Paul B moves in the direction of the arrow, inside the semicircular ring When entering the space, the sensor S detects it and sends the electric signal to the control unit via the electric wire 21. Then, as shown in FIG. 1, when a predetermined voltage is applied to the heating wire U via the relay section for a predetermined time based on this signal, the semicircular ring R reduces its radius of curvature. , You will grab Paul B. This state continues as long as the heating wire U is energized. When the energization of the heating wire U is stopped and the shape memory alloy 11 is cooled, the radius of the ring R increases, and as a result, the ball B is released from the ring R.

In Fig. 2, the device that composes and releases the object is shown as a device that constitutes the operating structure, but other devices that move, such as an expanding and contracting operating structure, bending or twisting are generated. An actuation structure or the like can also be used. Example

Next, the present invention will be described in more detail with reference to examples. Example 1

(1) Working structure

In FIG. 2, a semi-circular ring R was produced using the elastic plastic 12 as the molding material 13 while omitting the elastic support 12.

In this case, the wire diameter of the Ni—Ti alloy 11 was set to 1 mm, and the ring R was designed so that the high-temperature radius was 25 mm and the low-temperature radius was 26 mm.

Phase change Additional temperature A _s of the shape memory alloy was 36. 6 ° C.

As the sensor S, a photoelectric sensor (manufactured by OMRON, E32-DC200E) was used.

(2) Manufacture of the operating mechanism,

An operating mechanism having the configuration shown in FIG. 1 was manufactured using the operating structure.

In this mechanism, when an object (ball) B enters the space of the semi-circular ring R as its operating structure, the sensor S detects this and the control device [producer mable controller (PLC), OMRON, CPMZC] to transmit the electric signal from the sensor S, and the relay closes for a predetermined time based on the command from the PCL. A predetermined voltage is applied to the heating wire (Nichrome wire) U arranged on the ring R. The heating wire U generates heat by this, the shape memory alloy by the heat generation is heated, reaches its phase transformation temperature _{A s = 3 6. 6 °} C, grab the pole is closed ring R

When the pre-programmed time in the PCL has elapsed, the relay is opened by the command, the power to the shape memory alloy is stopped, the temperature drops, and as a result, the ring R opens and the ball is released. Industrial applicability

According to the present invention, since the motion stored in the shape memory alloy is performed in advance on the working structure, the use of a micromotor, gears, and the like is unnecessary, and as a result, the overall structure is simple and low A costly actuation mechanism can be obtained. The operation mechanism of the present invention is used as a manipulator or the like.

Claims

The scope of the claims

1. An operating structure unit, a sensor unit, a control unit, and a relay unit. The operating structure unit includes a shape memory alloy and an electric resistor for heating the alloy. A part configured to detect a change in the surrounding environment of the operating structure, the control unit configured by a computer, the relay unit configured by a relay, a δ operating mechanism, and the operating structure unit When a change occurs in the surrounding environment of the sensor, the change is detected by a part of the sensor, converted into an electric signal, and the electric signal is received by the control unit, and based on a transmission signal from the control unit. Operating the relay section to generate heat in the electric resistor of the operating structure section, heating the shape memory alloy by the heat generation, and performing an operation previously stored in the shape memory alloy. Shape memory alloy There was actuation mechanism.

2. The mechanism according to claim 1, wherein said sensor unit is disposed on said operating structure unit.

3. The actuating structure comprises a semi-circular ring-shaped body whose shape is changed by heating, and the ring-shaped body is

(i i) the shape memory alloy has a radius of curvature that is reduced or increased by heating;

(i i i) having an electric resistor for heating the alloy;

The actuation mechanism according to any one of claims 1 to 2, characterized in that: