JPH09280158A - Device for generating driving force - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a sufficient output by decreasing friction loss caused by an outer tube even in the case where a combination of a wire and the outer tube used for an output of a shape memory alloy. SOLUTION: To a wire 36 wound around a pulley 38, shape memory alloys 30 and 32 are connected to constitute a drive mechanism. The pulley 46 is connected to the wire 36 via a drive wire 42 so that pulley 46 and a robot hand 48 are reciprocated. The shape memory alloys 30 and 32 which are distorted is not prevented from being driven with the outer tube 50 thereby providing an efficient output.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a driving force generator for outputting a deforming force of a shape memory alloy to the outside to drive an object.

[0002]

2. Description of the Related Art A driving force generator is used which uses a deforming force of a shape memory alloy that expands or contracts at a predetermined temperature as a driving force. The shape memory effect of shape memory alloys excluding copper-based materials shows unidirectional characteristics with irreversible changes.

FIG. 2 shows an example of an apparatus for generating a driving force by utilizing only the contracting force of the shape memory alloys 10 and 12. The shape memory alloys 10 and 12 are fixed at one end and the wire 1 at the other end.
It is connected to the pulley 18 via the rollers 4 and 16. Since the pulley 18 reciprocates due to the stretching force of the shape memory alloys 10 and 12, the robot hand 20 can also be driven. Wire 1
4 and 16 need to have predetermined tension and rigidity in order to reduce the play of the robot hand 20, and a sufficient output can be obtained due to the frictional force between the outer tubes 22 and 24 and the elongation of the wire itself. There will be no.

[0004]

SUMMARY OF THE INVENTION It is an object of the present invention to obtain a driving force generator having a small output loss even when the driving force of a shape memory alloy is transmitted via a wire and an outer tube.

[0005]

According to a first aspect of the present invention, there is provided a driving force generator which reciprocates due to expansion and contraction of a shape memory alloy, a reciprocating member which outputs a driving force, and A pair of pulling wires that connect the driving force generating unit main body and the reciprocating member, transmit the reciprocating motion of the driving force generating unit main body to the reciprocating member as tensile forces, and reciprocate the reciprocating member, and these wires. And an outer tube that guides the wire by generating a frictional force between the wire and the outer circumference of the wire.

According to a second aspect of the present invention, there is provided a driving force generator, which is stretched between a first reciprocating member and a part of the reciprocating member and a fixed portion to pull the reciprocating member by a tensile force. The first shape memory alloy to be moved forward and the part of the reciprocating member are suspended between the fixed part and the opposite side via the reciprocating center, and the reciprocating member is returned by a tensile force. One of the second shape memory alloy, the second reciprocating member, and the second reciprocating member, which together with the first reciprocating member and the first shape memory alloy, form a driving force generating portion main body. Between the first retraction member and the second reciprocating member, which is laid between the second reciprocating member and a part of the driving force generating unit main body, and the first pulling wire opposite to the second reciprocating member via the reciprocating center. Second pulling wire which is hung between the side and the other part of the driving force generating portion main body to return the second reciprocating member. Covers the wires, is characterized by a pair of the outer tube for guiding the wire occurs a frictional force between the outer circumference of the wire.

As described above, according to the present invention, the main body of the driving force generator that reciprocates due to the expansion and contraction of the shape memory alloy has no friction with the outer tube, and there is no output loss due to this friction, resulting in an efficient driving force generation state. Become.

[0008]

1 shows a driving force generator according to an embodiment of the present invention. Shape memory alloy 3
0 and 32 are arranged in parallel, and one end of each is fixedly attached to the fixed wall 34. Wire 36 at the other end
Are respectively connected to both ends. The intermediate portion of the wire 36 is wound around the pulley 38. One ends of drive wires 42 and 44 are fixed to the middle portion of the wire 36, respectively. The shape memory alloys 30, 32, the wires 36, and the pulley 38 form the driving force generating unit main body A.

The other ends of the drive wires 42 and 44 are fixed to the opposite side of the pulley 46 with the rotating shaft interposed therebetween. A robot hand 48 projects from the pulley 46. The outer tube 5 is located between the drive wires 42 and 44.
The drive wire 4 is inserted even when the axes of 42 and 44 are bent, respectively.
The tensile forces of 2, 44 can be reliably transmitted to the pulley 46.

Here, wire 36 is simply drive wire 42,
Since it is provided to drive the robot 44, low tension is sufficient, while the wires 42 and 44 need to be given a predetermined tension in order to drive the robot hand 48 reliably.

The shape memory alloys 30 and 32 are designed to expand or contract at the operating point (52 ° C. in this embodiment). Therefore, one of the shape memory alloys 30 and 32 is heated or cooled by an unillustrated heating or cooling means. When one is heated and one is cooled, the pulley 38 revolves to reciprocate, and this reciprocating motion is transmitted to the pulley 46 and the robot hand 48 via the drive wires 42 and 44, and the output of the robot hand is generated.

In this case, the drive wires 42 and 44 generate a frictional force between the drive wires 42 and 44 and the outer tubes 50 and 52 to reduce the output, but the movement of the shape memory alloys 30 and 32 as the drive system may be hindered. Since it is not provided, an output about 30% larger than that of the conventional structure of FIG. 2 is obtained.

Shape memory alloy 3 used in this embodiment
0 and 32 are Ti—Ni alloys having a diameter of 0.495 mm, a length of 377 mm, a strain of 4%, and a maximum reciprocating displacement length of 30 mm.

[0014]

Since the present invention has the above-mentioned structure, it is possible to obtain the driving force generating device in which the output reduction is small due to the frictional force between the wire and the outer tube.

[Brief description of drawings]

FIG. 1 is a schematic plan view showing a driving force generator according to an embodiment of the present invention.

FIG. 2 is a schematic plan view showing a conventional driving force generator.

[Explanation of symbols]

A drive force generating body 30 shape memory alloy (first shape memory alloy) 32 shape memory alloy (second shape memory alloy) 36 wire 38 pulley (first reciprocating member) 42 drive wire (pulling wire, first) 1 pulling wire) 44 drive wire (pulling wire, second pulling wire) 46 pulley (reciprocating member, second reciprocating member) 48 robot hand (reciprocating member, second reciprocating member) 50 outer tube 52 Outer tube

Claims (2)

[Claims] 1. A drive force generator body that reciprocates by expansion and contraction of a shape memory alloy, a reciprocating member that outputs a drive force, and a drive force generator that connects the drive force generator body and the reciprocating member. The reciprocating motion of the main body is transmitted to each reciprocating member as a tensile force to reciprocate the reciprocating member. An outer tube that operates as a drive force generator. 2. A first reciprocating member, a first shape memory alloy which is hung between a part of the reciprocating member and a fixed portion to move the reciprocating member forward by a tensile force. The first reciprocating member and the first reciprocating member are reciprocally moved by a tensile force by being stretched between the fixed portion and the opposite side of the reciprocating member via the reciprocating center. A second shape memory alloy forming a driving force generating section main body together with the shape memory alloy, a second reciprocating member, a part of the second reciprocating member and a part of the driving force generating section main body. A first pulling wire which is laid between the two reciprocating members to move it forward; and an opposite side of the second reciprocating member via the reciprocating center and another part of the driving force generator main body. And a second pulling wire which is hung between the wire and the second reciprocating member to move back, Driving force generating device comprising a pair of outer tube for guiding the wire occurs a frictional force, to have a between.