JPS59211773A - Thermal-to-mechanical energy converter - Google Patents

Abstract

PURPOSE:To enlarge the stroke of a mobile part and to allow the form recovering force to reduce an angle two members, by utilizing the tendency of form recovery from the state of elongated deformation of a form-memorizing alloy, in a thermal-to-mechanical energy converter using said form-memorizing alloy. CONSTITUTION:The pivotal axis 3 of two members 1 and 2 which are joined with each other in a relatively rotatable manner is adjusted to coincide with the axis of a form memorizing alloy wound part 4. A string-like form memorizing alloy 5 is wound around the part 4 and its both ends are fixed to the members 1 and 2. A means of heating the form memorizing alloy 5 is provided, while said means being consisting of an electrifying or light radiating means. The members 1 and 2 are energized with a spring so that they are separated widely in the angular positions, while the form memorizing alloy 5, shows its maximum length, under the cooled state. When heated, the form memorizing alloy 5 shrinks from its full length due to the tendency of recovering its memory form (straight form), whereby reducing the angle between the members 1 and 2 and making the member 1 swing at a high speed.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field) The present invention relates to a thermo-mechanical energy conversion device that converts thermal energy into mechanical energy using a shape memory alloy.

(Prior art).

This type of device utilizes the recursive force J (hereinafter referred to as shape recovery force) that occurs during the process in which a shape memory alloy recovers from a deformed state to a memorized shape. It is well known that when a memory alloy is subjected to elongation deformation, Φ becomes significantly larger than when it is subjected to bending deformation or torsional deformation.

Also, related to this, the speed at which a shape memory alloy recovers from a deformed state to its memorized shape is faster when subjected to elongation deformation than when subjected to bending or torsional deformation. is also well known.

Therefore, in this type of device 63, it is desirable to apply elongation deformation to the shape memory alloy and utilize the shape recovery force from the elongation deformation.

However, in the past, as described above, elongation deformation is applied to the shape memory alloy, and the shape recovery force from the elongation deformation is
When trying to use it, it was difficult to increase the stroke of the movable part of the device, so we mainly applied bending deformation (and torsional deformation) to the shape memory alloy and created a shape from that bending deformation (and torsional deformation). He used his resilience. Therefore, there are disadvantages in that only a relatively small force can be generated and the operating speed is relatively slow.

Therefore, the present applicant first applied for patent application No. 57-118457.
In this issue, we proposed a thermo-mechanical energy conversion device that utilizes the shape recovery force of a shape memory alloy from elongation deformation, can increase the stroke of the movable part, and is suitable for use in manipulator arms, etc. .

In this device, one end side of a linear shape memory alloy is attached to one of two members rotatably connected to each other, and the shape memory alloy is attached to the other of the two members. The other end of the alloy is attached, and the middle part of the shape memory alloy is wrapped around the shape memory alloy wrapping part, but in the embodiment disclosed in the application of the present applicant,
In both cases, the shape recovery force of the shape memory alloy acted in a direction that increased the angle between the two members.

[Purpose of the invention]

The present invention was made in view of these circumstances, and is an IC.
A thermo-mechanical method that utilizes shape recovery from elongation deformation of shape memory alloys, can increase the stroke of the movable part, and that the shape recovery force acts in the direction of reducing the angle between two members. 7 [Summary of the Invention] A thermo-mechanical energy conversion device according to the present invention comprises two members rotatably connected to each other, and a shape memory alloy wrapped member. and a wire whose one end is attached to one of the two members and the other end is attached to the other of the two members, and whose middle part is wrapped around the shape memory alloy wrapping part. The shape memory alloy comprises a shape memory alloy having a shape and means for applying a tensile force to the shape memory alloy, and the shape memory alloy has a shape memory alloy whose shape increases as the angle between the two members increases. The above object is achieved by being wrapped around the shape memory alloy wrapping portion in a manner that increases elongation deformation.

〔Example〕

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in more detail below based on embodiments with reference to the drawings.

In FIGS. 1 and 2, one end of a structural member 1 and a structural member 2 are connected to each other by a shaft 3 so as to be relatively rotatable. A pulley-shaped shape memory alloy wrap @4, which constitutes a shape memory alloy wrap in this embodiment, is fixed to the structural member 1 with its center aligned with the shaft 3.

5 is a linear shape memory alloy such as a Ti-JJi alloy, and this shape memory alloy 5 has one end attached to the structural member 1, the other end attached to the structural member 2, and an intermediate portion. The shape memory alloy wrapping material 4 is wound around the shape memory alloy wrapping material 4. Here, the shape memory alloy 5 memorizes a straight shape as shown in FIG. 3 by being subjected to a predetermined shape memory treatment, and the total length of the alloy 5 in this memorized shape is It is L.

Further, the shape memory alloy 5 is wound around the shape memory alloy wrapping material 4 in a cross state, so that when the angle θ between the structural members 1 and 2 increases, the shape memory alloy 5 The elongation deformation ΔL is made to be large.

A spring 6 is interposed between the structural members 1.2 (
(See FIG. 2), this spring 6 biases the structural member 1.2 in the direction in which the angle θ increases.

Further, the shape memory alloy 5 is connected to the current supply device 7 at both ends thereof.

Next, the operation of this embodiment will be explained.

If no current is applied to the shape memory alloy 5 and the alloy 5 is cooled, the force of the spring 6 will cause the angle θ between the structural members 1.2 and the shape memory alloy 5 to The elongation ΔL is at its maximum.

Next, when an appropriate amount of current is passed through the shape memory alloy 5 from the current supply device 7, the alloy 5 is heated by Joule heat,
When the temperature reaches a certain level or higher, phase transformation begins, and due to the shape memory effect, it attempts to return to the memorized shape (straight state) shown in FIG. 3.

Therefore, in terms of the expansion and contraction direction, the shape memory alloy 5 has a shape memory alloy 5 whose total length is L (in other words, ΔL is 0).
try to shrink)

Therefore, if the structural member 2 is now fixed, the structural member 1 will be as shown by the dashed line in FIG.
The structural member 1. is rotated clockwise in the figure against the spring 6.
The angle θ between the two becomes smaller.

Note that since the shape memory alloy 5 is linear, its shape recovery force from bending deformation is small, so the shape memory alloy 5 exhibits only slight shape recovery with respect to bending deformation.

Since this thermo-mechanical energy conversion device utilizes the shape recovery force of the shape memory alloy 5 from elongation deformation as described above, the structural member 1 can be driven at high speed with a very large force.

Furthermore, if the elongation ΔL of the shape memory alloy 5 is too large, plastic deformation will occur and complete shape recovery will not occur, so the ΔL cannot be increased beyond a certain level. In the target energy conversion device, the minute change in ΔL is greatly magnified and the displacement of the structural member 1 becomes large, so that the stroke of the structural member 1 can be increased.

Note that when the energization by the energizing device 7 is stopped and the shape memory alloy 5 is cooled, the 414-shaped member 1 is
is rotated counterclockwise in the figure, and the angle θ becomes large again.

In addition, the elongation Δ of the shape memory alloy 5 during heating and the angle θ between the structural members 1 and 2 are determined by the progress state of phase transformation of the shape memory alloy 5, and by extension the magnitude of the thermal energy input to the shape memory alloy 5. correspond to the situation.

Therefore, by controlling the magnitude of the current flowing from the energizing device 17 to the shape memory alloy 5, the structural member 1.2
It is possible to control the angle θ between tlNl-.

In the above embodiment, the part of the shape memory alloy wrapping material 4 on which the shape memory alloy 5 is wrapped is circular, and its center is aligned with the shaft 3; The said part of 4 does not necessarily have to be circular, nor does it need to have its center coincide with the axis 3.

Then, depending on the shape of the portion of the shape memory alloy wrapped @ 4 and the positional relationship between the portion and the shaft 3, the relationship between the angle θ and the elongation ΔL, and the angle θ when the shape memory alloy 5 is energized. The characteristic curve can be changed without showing the relationship between the torque and the torque generated by the device.

In the above embodiments, the shape memory alloy wrapping material 4 is a separate member from the structural member 1, but the shape memory alloy wrapping material 4 may be provided integrally with the structural member 1.

Alternatively, the shape memory alloy wrapping material 4 is made a separate member from the structural member 1, and the shape memory alloy wrapping material 4 is not fixed to the structural part ui, and the wrapping material 4 is attached to any of the structural members 1.2. It may also be rotatable.

Further, in the above embodiments, the shape memory alloy is heated by electrical heating, but in the present invention, the shape memory alloy may be heated by other methods such as irradiation with a laser beam or ordinary light.

Furthermore, in the above embodiment, a spring is used to stretch and deform the shape memory alloy, but it is also possible to use a structure in which the shape memory alloy is stretched and deformed by a force other than the spring force. It goes without saying.

〔Effect of the invention〕

As described above, the thermal-sonological one-energy conversion device according to the present invention utilizes the shape recovery from elongation deformation of the shape memory alloy, can increase the stroke of the movable part, and furthermore, the shape recovery force can be increased. This has the excellent effect of reducing the angle between the two parts.

[Brief explanation of drawings]

FIG. 1 is a front view showing an embodiment of a thermo-mechanical energy conversion device according to the present invention, and FIG. 2 is a plan view showing the same embodiment.
FIG. 3 is a front view showing the memory shape of the shape memory alloy included in the same example. 1.2... Structural member, 3... Shaft, 4... Shape memory alloy wrapping material, 5... Shape memory alloy, 6... Spring. Figure 1 4 Figure 2

Claims (1)

[Scope of Claims] Two members rotatably connected to each other, a shape memory alloy wrapping portion, one end of which is attached to one of the two members, and the other end of which is attached to one of the two members. A linear shape memory alloy is attached to the other back of the member, and the intermediate portion is wound around the shape memory alloy wrapping portion, and a means for applying a tensile force to the shape memory alloy is provided. Therefore, when the angle between the two members increases, the elongation deformation of the shape memory alloy increases. A thermo-mechanical energy conversion device characterized in that the shape memory alloy is unwound on the shape memory alloy winding part in a different relationship. ,.