JPH0529792B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a reciprocating device using shape memory elements.

[Conventional technology and its problems]

Conventionally, there is an actuator, for example, as a device that performs reciprocating movement using a shape memory alloy, and in this actuator, the shape memory alloy is controlled to be heated and cooled to hold a desired article.

The method of controlling heating and cooling of this shape memory alloy plate is as follows: (1) Hot air and cold air are blown onto the shape memory alloy.

(2) A current is applied to generate heat due to the resistance of the shape memory alloy itself.

However, both methods require time to heat and cool the shape memory alloy, which has a large heat capacity, to return to its original shape, and the time required for cooling is particularly long, making it difficult to respond quickly to repeated use. There was a problem with the rapid response of the device.

[Means to solve the problem]

The present invention speeds up repetitive motion by using a plurality of shape memory elements each having an opposing shape memory effect: a shape memory effect at a predetermined temperature and a shape memory effect at a predetermined temperature raised by heating. This is a plate-shaped shape memory alloy that is curved with respect to the center line at room temperature, and is memorized to curve in the opposite direction from the curved state at room temperature at a predetermined high temperature. Two curved plates made with alternating cuts perpendicular to the center line and reinforced with hard electrical insulating material on both ends parallel to the center line are connected so that their curves are opposite to each other. In a device in which one end is fixed and the other end is free, each shape memory alloy is alternately and repeatedly controlled to be energized, and by repeating heating and natural cooling, the bending direction changes, and the free side tip changes. The gist is that the section performs left-right fluctuations.

〔Example〕

The present invention will be explained below based on embodiments shown in the drawings.

First, a first embodiment of the present invention will be explained. The shape memory alloy plate 1 as the shape memory element used in the reciprocating device in this embodiment has the required width, length and thickness as shown in FIG. A slit 2 is cut in the plate 1, and connecting terminal portions 3, 3 are formed at both ends of the plate 1, and a current is caused to flow between the connecting terminal portions 3, 3 at both ends. At this time, the current path becomes a meandering line as shown by the arrow in FIG. 3, and heat is generated due to the electrical resistance of this plate. If the electrical resistance between these terminals is r, the current i flowing through the plate 1 generates a heat amount of Qli ² r and the temperature of the shape memory alloy plate 1 increases. Since this plate alone cannot provide the mechanical strength of a plate, reinforcing plates 4, 4 made of a hard insulating material are sandwiched on both sides of the plate 1 to integrate it. This state is shown in FIGS. 1 and 2. In this way, a pair of shape memory alloys 1 integrally provided with reinforcing plates 4, 4 on both sides are used as opposed to each other. For example, when implemented as a gripping device as shown in FIG. 1, two pairs of shape memory alloy plates are used.

As shown in Fig. 4, this shape memory alloy plate 1 is curved as shown in Fig. 4A at room temperature, and when it becomes high temperature by supplying electricity to it, it curves as shown in Fig. 4B.
The shape is memorized and manufactured so that it curves to the opposite side as shown in the figure.

Next, the gripping device shown in FIG. 1 will be explained.

In the figure, 1A and 1B are a pair of shape memory alloy plates that curve outward from each other as shown in the figure at room temperature, and 1C and 1D are a pair of shape memory alloy plates that curve inward toward each other at room temperature. Using these two pairs of shape memory alloy plates, first, reinforcing plates 4, 4 provided at one ends of the alloy plates 1C, 1D are fixed to the frame 5. The other pair of alloy plates 1 and 1 are connected to the other end sides of the opposing alloy plates 1C and 1D through reinforcing plates 41 and 41 that also serve as connectors.
Fix one end of A and 1B. At this time, although the reinforcing plates 4, 4 provided on the alloy plates 1A and 1C, 1B and 1D facing each other are not shown, they are fixed using other connecting tools, and the alloy plates 1A and 1C, 1B and 1D are fixed together. The alloy plates 1A, 1C and 1B, 1D are made to face each other. And these alloy plates 1A, 1B
Attachments 61 and 62 suitable for use as a gripping device are protruded from the reinforcing plate 6 at the tip thereof.
The shape of this attachment is shown in the figure.
Although we used the method of inserting it under the body, it is also possible to use a sandwiching method or other shapes as appropriate.

Next, the operation of the gripping device constructed as described above will be explained.

Now, at room temperature, the gripping device having the structure shown in FIG. 1 is moved to position the object G to be held between two opposing shape memory alloy plates 1A and 1B.

FIG. 5A shows an example of a time-temperature curve when a shape memory alloy plate is electrically heated and cooled;
shows the cases of shape memory alloy plates 1C and 1D, respectively. T1 indicates room temperature, and T2 indicates a high temperature higher than room temperature at which the shape memory alloy plate changes shape.

t1 indicates the time to heat the shape memory alloy plates 1A and 1B to high temperature, and t2 indicates the time to heat the shape memory alloy plates 1C and 1D to high temperature, respectively.

FIG. 6 is an explanatory diagram showing a state in which each shape memory alloy plate constituting the gripping device shown in FIG. 1 undergoes shape memory change according to the time-temperature curve shown in FIG. 5A. It is. In this figure, even if the reinforcing plate 6 at the tip of the shape memory alloy plates 1A and 1B is displaced, the article G protruding from the reinforcing plate 6
It shows the state of change of the attachments 61 and 62 that hold the .

In FIG. 6, when the distance between the center line C-C' passing through the center 5a of the frame 5 and the reinforcing plate 6 is the displacement l, the temporal change in displacement between each member is 5
It will look like the curve shown in Figure B.

FIG. 6A shows the case at room temperature, where the change l=l1.

From this state, a pair of shape memory alloy plates 1A, 1
When B is energized, it is heated, and after t1, the high temperature T1
As a result, the shape memory alloy plates 1A and 1B change their shape and reach the state shown in FIG. It is held between the two.

Next, in order to release the sandwiched article G, the power supply to the shape memory alloy plates 1A and 1B is stopped, and the power is supplied to the other pair of shape memory alloy plates 1C and 1D. After t2, the temperature reaches T1, and the shape memory The alloy plates 1C and 1D change their shape and become in the state shown in FIG. 6C.

In this case, since the other pair of shape memory alloy plates 1A and 1B are connected to the tips of the shape memory alloy plates 1C and 1D via reinforcing plates 41 and 41, the shape memory alloy plates 1C and 1D are The shape change also affects the shape memory alloy plates 1A and 1B. In other words, even if the shape memory alloy plates 1A and 1B stop energizing, cooling from high temperature to room temperature is done by natural cooling, so it is not possible to return to the original room temperature shape instantly, but it takes a certain amount of time. becomes.

Therefore, shape memory alloy plates 1A and 1B are shown in FIG. 6B.
Since the state shown in FIG. 6C is maintained, the shape memory alloy plates 1C and 1D change their shapes to become the state shown in FIG. 6C. In this case, the displacement l=l1, and the distance between the reinforcing plates 6, 6 is □× as in the case shown in FIG. 6A.
2, and the article G is released from the opposing attachments 61 and 62.

FIG. 6D shows a state in which the shape memory alloy plates 1A and 1B are cooled and returned to normal temperature after a certain period of time has passed.

Further, when the current supply to the shape memory alloy plates 1C and 1D is stopped, the gripping device returns to the normal temperature state shown in FIG. 6A when the shape memory alloy plates 1C and 1D are cooled and returned to the normal temperature state after a certain period of time.

In this way, the article G can be held and released by only sequentially applying electricity to and heating the shape memory alloy plates 1A, 1B, 1C, and 1D facing each other, and can be used as a gripping device. Regardless of whether each shape memory alloy plate is cooled and returns to its original state at room temperature, by heating the shape memory alloy plate, it is possible to clamp and release objects, making it extremely responsive and fast. It becomes a responsive device.

Although the gripping device has been described as an example, the gripping device is not limited thereto, and as shown in FIG. Since the displacement □×, which is the distance from the center line C-C' passing through the center 5A, can be varied, it can also be used as a reciprocating device.

In addition, in this example, two sets of shape memory alloy plates 1A, 1B and 1C, 1D are used to face each other, but this is not limited to two sets, and it is possible to combine three or more sets. Of course. Furthermore, it goes without saying that the shape to be memorized by the shape memory alloy plate is not limited to the curved shape shown in this embodiment, but may be any other predetermined shape.

Further, in this example, two sets of shape memory alloy plates are arranged to face each other, but one set of shape memory alloy plates 1B and 1D, for example, are fixed without moving, and shape memory alloy plates 1A and 1C are fixed. A similar effect can be obtained even if only one part is movable.

In this example, the shape memory alloy plate has the required width, length, and thickness as shown in Fig. 3, and has a shape in which slits are cut into each other at regular intervals from both sides. Since the method was used to heat the device by passing an electric current through it to generate heat, it does not have a negative impact on the surrounding environment.

Note that the shape of the shape memory alloy plate is not limited to this, and it goes without saying that the method of heating the shape memory alloy plate is not limited to this either.

Next, a gripping device shown in FIG. 7 will be described as a second embodiment of the present invention.

In the figure, 11 is a shape memory alloy spring formed into a spring shape that assumes an elongated shape at room temperature.
12 is a shape memory alloy spring formed into a spring shape that assumes a predetermined compressed shape at room temperature. First, the supporting members 21, 21 are fixed to both sides of the frame 41, and the spring fittings 22, 22 are fixed to the inner surfaces of the other ends of the supporting members 21, 21. This spring stopper 22
Shape memory alloy springs 11 and 12 are disposed at the other ends of the shape memory alloy springs, and spring stoppers 23 and 23 are disposed at the other ends of the shape memory alloy springs, so that the shape memory alloy springs 11 and 12 face each other.
At the tip of this spring stopper 23 are attachments 31, 3 suitable for use as a gripping device.
2 is provided protrudingly. The shape of this attachment is
In the illustration, a method is shown in which it is inserted under the clamped article G, but a clamping method or other shapes can be selected and used as appropriate. The shape change of the shape memory alloy springs 11 and 12 in this embodiment will be explained based on the diagram shown in FIG.
shows an elongated shape as shown in FIG. 8A at room temperature, and shows a predetermined compressed shape shown in FIG. 8B by heating, and the shape memory alloy spring 12 shows a predetermined compressed shape shown in FIG. 8B at room temperature. They are manufactured by memorizing their respective shapes so that they exhibit a predetermined compressed shape and then, by heating, exhibit an expanded shape as shown in FIG. 8A.

Next, the gripping device constructed as described above will be explained.

Now, at room temperature, the gripping device having the structure shown in FIG. 7 is moved to position the portion G to be held between the two sets of shape memory springs 31 and 32 facing each other. FIG. 9 is an explanatory diagram showing a state in which each shape memory alloy spring constituting the gripping device shown in FIG. 7 undergoes shape memory change.

This figure shows that the article G can be held by changing the distance between the attachments 31 and 32.

FIG. 9A shows the case at room temperature, at which time the distance between the attachments 31 and 32 is L=L1.
When the shape memory alloy spring 32 is heated from this state, its shape changes and becomes the elongated shape shown in FIG. 8A, and the gripping device becomes the state shown in FIG. , the article G is attached to the opposing attachment 31,
It is held at 32.

Next, in order to release the clamped article G, the heating of the shape memory alloy spring 32 is stopped, and
When the other shape memory alloy spring 31 is heated, its shape changes to the compressed shape shown in FIG. 8B, and the gripping device is in the state shown in FIG. , the article G is attached to the opposing attachments 31, 3.
It will be released from 2.

When the release of the article G is completed, the shape memory alloy spring 31,
32 respectively. Shape memory alloy spring 31,3
2 is cooled and returned to the normal temperature state, and the gripping device returns to the normal temperature state shown in FIG. 9A.

In this way, only by sequentially heating the opposing shape memory alloy springs 31 and 32, the article G can be held and released, and can be used as a gripping device.

It is extremely responsive and adaptable because it can clamp and release objects by heating the shape memory alloy plate regardless of whether each shape memory alloy spring is cooled and returns to its original state at room temperature. It becomes a device.

Although the gripping device has been explained as an example, the present invention is not limited to this, and since the spacing between the attachments can be varied by the shape memory of the shape memory alloy spring, it can also be used as a reciprocating device. can.

Further, in the embodiment, the shape memory alloy plate springs 31 and 32 are used as opposing shape memory alloy leaf springs, but the present invention is not limited to this, and other combinations are of course possible.

〔Effect of the invention〕

According to the present invention, the shape memory elements are sequentially arranged using a plurality of shape memory elements each having a shape memory effect in which the shape memory effect at a predetermined temperature and the shape memory effect at a predetermined temperature raised by heating are contradictory. By heating and changing shape at high temperatures, rapid repetitive motions can be performed without the need for time for each shape memory element to cool down and return to its pre-heated state, making it extremely responsive and fast. This has the effect of realizing responsive reciprocating motion.

Furthermore, since the device of the present invention has no friction or sliding parts, it is an optimal reciprocating device especially in clean rooms where dust generation is averse.

[Brief explanation of the drawing]

Fig. 1 is a front view showing a gripping device according to the first embodiment of the present invention, Fig. 2 is an external view of one unit, Fig. 3 is an explanatory view of the shape memory alloy, Fig. 4 is an explanatory view of the operation,
FIG. 5A is a diagram showing an example of a time-temperature curve when a shape memory alloy plate is electrically heated and cooled.
FIG. B is a diagram showing temporal changes in the displacement of the reinforcing plate 5, FIG. 6 is an explanatory diagram showing the state in which the shape of each shape memory alloy plate changes, and FIG. 7 is a diagram showing a second embodiment of the present invention. 8 is an explanatory view of the operation, and FIG. 9 is an explanatory view showing the state in which the shape of each shape memory alloy spring changes. 1 is a shape memory alloy plate, 2 is a slit, 3 is a connecting terminal portion, and 4 is a reinforcing plate.

Claims (1)

[Claims] 1. A plate-shaped shape memory alloy that is curved with respect to the center line at room temperature, and is memorized to curve in the opposite direction from the curved state at room temperature at a predetermined high temperature. Then, two curved plates, which are reinforced with hard electric insulating material on both ends parallel to the center line, are connected so that the curved states are opposite to each other, In a device in which one end is fixed and the other end is free, each shape memory alloy is alternately and repeatedly controlled to be energized, and by repeating heating and natural cooling, the bending direction changes, and the free side tip changes. A reciprocating device characterized by horizontal movement.