JPH0236955Y2 - - Google Patents

Description

[Detailed Description of the Invention] <Technical Field> The present invention relates to a thermally driven rotating device that obtains rotational force through heat.

<Prior Art> Heat-driven rotation devices that utilize shape memory alloys such as Ni-Ti alloys to obtain rotational force have been well known.

For example, in Utility Model Application Publication No. 58-163688,
As a first embodiment, a large pulley and a small pulley are integrally provided on the same rotating shaft to form a first pulley body, and similarly to this first pulley body, the large pulley and small pulley are mounted on the same A second pulley body is formed integrally with the rotating shaft, and the first and second
The first pulley body is placed in a position where the large pulley and the small pulley face each other, and a shape memory alloy wire is crossed between the two pulleys.
It has been proposed that terminals of an electrical circuit for supplying power are connected to the small pulley of the second pulley body and the large pulley of the second pulley body, and rotational force is obtained by supplying current to the pulleys between them. has been done.

In this device, the wires have a shape memory so as to contract, and when the current is supplied, the shape memory alloy wires generate heat and take on the memorized, contracted shape, thereby causing the wires to mutually interact with each other. A wire installed between the two pulley bodies draws each other so as to rotate them in opposite directions, and at this time, the wire is hung on one pulley body on the small pulley and the other pulley body on the large pulley. This causes a torque difference, and this torque difference continues the rotational motion.

In addition, the same publication describes a second embodiment in which a plurality of pulley bodies are formed by integrating a large pulley and a small pulley, a ring-shaped wire made of a shape memory alloy is installed on the large pulley, and a shape memory alloy ring wire is installed on the small pulley. It has been proposed that a conventional ring-shaped wire is installed.

This is achieved by heating a part of the shape memory alloy wire and transmitting the torque difference between the pulley bodies using a normal non-stretchable wire to continue the rotational motion. It is becoming more and more like this.

The heat-driven rotation device described above heats the wire by supplying current to the pulley or shape memory alloy wire, making the heating method simpler than those using hot water or hot air. There are benefits to doing so. However, since it is necessary to provide the large pulley and the small pulley integrally on the same axis, a certain amount of thickness in the axial direction must be ensured, and there is a problem that it is not possible to reduce the thickness. Moreover, because the shape memory alloy wire needs to have a shape memory so that it shrinks when heated (for example, it needs to be formed into a small coil shape), there is a natural limit to the miniaturization of the device.

<Objective> The present invention has been made in view of the above points, and provides a compact thermally driven rotation device.

<Example> Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is an explanatory diagram of an embodiment of the present invention. In this FIG. 1, 1 is a large pulley, 2 is a first small pulley disposed facing the large pulley 1 at a predetermined distance, and 3 is between the large pulley 1 and the small pulley 2. It is a suspended shape memory alloy wire (hereinafter referred to as SMA wire). this
The SMA wire 3 has an annular shape and is loosely installed between the large pulley 1 and the small pulley, and has a linear shape memorized when heated and transformed into a high temperature phase. It goes without saying that the pulleys 1 and 2 are rotatably supported by shafts 4 and 5, and the small pulley 2 is made of a conductive material.

6 is a second small pulley that partially contacts this SMA wire 3 and is disposed between the large pulley 1 and the first small pulley 2. This second small pulley 6 is made of a conductive material and is rotatably supported by a shaft 7, and the shaft 7 supporting this pulley 6 is supported so as to be freely movable in the radial direction. 8 is a wire stretched between the shaft 7 and the fulcrum 9 to move the shaft 7; 10 is a bias spring installed between the central portion of the wire 8 and the fulcrum 11; is biased in the direction of contraction. Therefore, the bias spring 10 acts to cause the second small pulley 6 to apply a constant tension to the SMA wire 3. 12
is an electric circuit for applying voltage between the first small pulley 2 and the second small pulley 6, and this electric circuit 12 is connected to a DC power supply 13 and the (+) and (-) terminals of this power supply 13. from the electric wire 14 connecting to each of the small pulleys 2 and 6, the first small pulley 2, the second small pulley 6, and the SMA wire 3 installed between the first small pulley 2 and the second small pulley 6. It is a closed DC circuit consisting of Therefore, by configuring the DC closed circuit, a DC current flows between the first and second small pulleys 2 and 6, but the SMA
In the wire 3, the length between AC is shorter and the resistance is lower than that between ABC, so a larger current flows than between ABC, and the amount of heat generated per unit volume of the SMA wire increases between AC.

Now, the rotational operation of the device having the above configuration will be explained.

First, as mentioned above, the first
When current flows between the second small pulleys 2 and 6, AC
The SMA wire 3 between the ACs generates heat, and finally the SMA wire 3 between the ACs transforms into a high-temperature phase. In other words, from A, which is the contact point between the SMA wire 3 and the first small pulley 2,
The SMA wire 3 up to point C, which is the contact point between the SMA wire 3 and the second small pulley 6, is transformed into a high temperature phase.

When the SMA wire 3 between the ACs transforms into a high-temperature phase in this way, the shape memory behavior between the ACs becomes as shown in FIG. 2. That is, as shown in FIG. 2, in the SMA wire 3 between ACs, the part that is in contact with the first pulley 2 (i.e., the part that is bent in an arc shape) is in contact with the second small pulley 6. There are many compared to the parts where there are. In other words, it is bent more on the first small pulley 2 side, and relatively less on the second small pulley 6 side. Therefore, the first and second
SMA wire 3 between small pulleys 2 and 6 is the second
Assuming that the shape is approximately straight due to the tension adjustment action of the small pulley 6, in the first small pulley 2, a force F is applied in the tangential direction as a force that causes the arc-shaped SMA wire 3 in contact with the pulley 2 to return to the straight shape. Similarly, a force f also acts on the second small pulley 6 in the tangential direction. These forces F and f both act as rotational moments Fr and fr that rotate the rotatably supported pulleys 2 and 6 in opposite directions.
As mentioned above, the first small pulley 2 is bent into an arc shape relatively many times, and the second small pulley 6 is bent relatively little, so the small pulleys 2, 6. Both rotate counterclockwise.
As a result of this operation, the wire 3 begins to rotate counterclockwise, and at the same time as it comes into contact with the pulley 2, it transforms into a high temperature phase and continues the above operation.
The movement of the SMA wire 3 also causes the large pulley 1 to rotate counterclockwise. Note that after leaving the second small pulley 6, the SMA wire 3 passes a small amount of current, but the amount of heat generated is very small, and is cooled by the outside air.
The SMA wire 3 between ABC transforms into a low temperature phase.

The rotating device can drive a driven object using the drive rotation of the large pulley 1. For example, if this rotation is transmitted to the wheels, it acts as a traveling device,
Further, by arranging appropriate mechanical means, it is possible to perform rocking motion, etc., and various applications can be considered.

In the above embodiment, if the current value of the power source 13 is changed, the amount of heat generated by the SMA wire 3 between ACs can be changed, and the generated force F also changes due to the change in the amount of heat generated. The rotation speed can be controlled by controlling the current value.

<Effects> As described above, the present invention includes a large pulley, a first small pulley formed to have a smaller diameter than the large pulley, and an annular shape memory alloy constructed between the large pulley and the first small pulley. a second small pulley disposed near the small pulley and in contact with the shape memory alloy wire; the shape memory alloy wire has a linear shape memorized; The position of the pulley is set such that the curvature of the wire contacting part of the second small pulley is smaller than the curvature of the wire contacting part of the first small pulley, and The small pulleys are both made of electrically conductive material and are a thermally driven rotating device equipped with an electrical circuit that supplies current to both pulleys.

Therefore, by supplying a current between the first small pulley and the second small pulley, the shape memory alloy wire between the small pulleys recovers its shape into a straight line, and this shape recovery The rotational motion can be continued by the torque difference generated by the .

In this case, since each pulley can be arranged approximately two-dimensionally, the device can be made thin. Moreover, since the shape memory alloy wire is memorized in a linear shape, it is possible to achieve a smaller size compared to a conventional device in which the shape memory alloy is memorized so as to shrink. Therefore, by making these devices thinner and smaller, the range of application of the thermal rotation drive device can be expanded.

[Brief explanation of the drawing]

FIG. 1 is a front view of an embodiment of the present invention, and FIG. 2 is an explanatory diagram of the same operation. 1...Large pulley, 2...1st small pulley, 3
...Shape memory alloy wire, 6...Second small pulley, 12...Electric circuit.

Claims (1)

[Claims for Utility Model Registration] A large pulley, a first small pulley formed to have a smaller diameter than the large pulley, and an annular shape memory alloy constructed between the large pulley and the first small pulley. wire, and a second wire disposed near the small pulley and in contact with the shape memory alloy wire.
a small pulley, the wire of the shape memory alloy has a linear shape memorized, and the second small pulley has a second small pulley with respect to the curvature of the wire contact portion of the first small pulley. The position of the pulley is set so that the curvature of the wire contact part is small, and the first small pulley and the second small pulley are both made of a conductive material, and current is supplied to both of the small pulleys. A thermally driven rotating device equipped with an electric circuit to