JPH03294666A - Inch worm mechanism using shape memory alloy - Google Patents

Abstract

PURPOSE:To carry out inch worm operation effectively by controlling a clamp mechanism clamping a shape memory alloy rod and a driving unit alternately. CONSTITUTION:A driving unit 4 consists of a pair of clamp mechanisms 6 clamping a shape memory alloy rod 1, feeder terminals 5 provided unsymmetrically on both sides of each clamp mechanism 6, a power source 7 supplying power to each terminals 5 and a switch 8. The driving unit 4 and the clamp mechanisms 6 are operated alternately by controller. Thereby the inch worm operation can be carried out effectively.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an inchworm mechanism using a shape memory alloy.

(Prior Art) In order to construct an actuator that performs linear motion using a shape memory alloy, the conventional method has been to process the shape memory alloy into a spring shape and counterbalance the springs. but,
In this method, springs are placed on both sides of the object to be moved, and movement is possible only between the points of balance of the springs.
If you try to increase the displacement, the actuator also becomes larger.

(Problem to be solved by the invention) The amount of deformation of a shape memory alloy that can be used as a type of thermally driven actuator only by electrical heating and natural cooling is usually from several percent to 1%.
It is necessary to keep it below. Therefore, in order to increase the amount of displacement, the actuator itself must also become larger.

The present invention aims to increase the amount of displacement of a shape memory alloy, and to provide an inchworm mechanism with a simple structure for operation.

(Means for solving the problem) A pair of clamp mechanisms for clamping a shape memory alloy, a feeder provided asymmetrically on both sides of each clamp mechanism,
It consisted of a drive unit consisting of a power supply and a switch for feeding power to each feeder, and a control device that alternately operated the drive unit and the clamp mechanism.

In addition, two pairs of feeders are provided asymmetrically on both sides of the clamp mechanism to enable movement in opposite directions.

(Example) FIG. 1 shows the basic configuration of the present invention. 1 is a wire or tape-shaped shape memory alloy, and 2 is a moving unit 1 to 2 covered with the shape memory alloy 1. 3 is a linear guide that guides the unit, and 4 is a drive unit.

Note that if the moving unit 2 is fixed and a linear guide 3 is provided on the unit 2 to guide the drive unit 4, the moving units 1 to 4 can also act as moving actuators.

FIG. 2 shows the configuration of the drive unit 4. Drive unit 4
It consists of a feeder 5 for passing current through the shape memory alloy 1 and a clamp mechanism 6 for clamping the shape memory alloy 1. The feeder 5 is installed so as to be asymmetrical with respect to the clamp mechanism 6 (that is, the center of the clamp mechanism 6 and the center of the feeder 5 do not coincide). In the case of FIG. 2, it is composed of two units each including four feeders 5, a pair of clamp mechanisms 6, a heating power source 7, and a switch 8 for controlling them. 9 is a spring for suppressing the feeding electron.

(Operation) The operation principle will be explained based on the diagram shown in Fig. 3 (in the figure, the drive unit 4 side is depicted as moving, but this is due to the relative movement between the shape memory alloy 1 and the drive unit 4). If the drive unit 4 is fixed, the shape memory alloy 1 side, that is, the moving unit side moves).

(1) Close the switch 8Ω1 on the left side, heat the diagonally shaded area to turn it into an austenite phase, and then clamp the shape memory alloy 1 with the clamp 6Q on the left side. At this time, the rigidity of the shaded area is high, and the strain rate of this area is smaller than that of other areas. (If we consider the state of force balance, the strain rate in the austenite phase part will be small and that in the martensitic phase part will be large.)
.

(2) When the forces are balanced, clamp 6 on the right side
Clamp with r.

(3) After clamping with the right clamp 6r, release the left clamp 6Q, open the left switch 8Q□, and close the right switch 8r. After this operation, the part directly under the left clamp 6Q that was in the austenite phase cools and changes to the martensite phase, and the shaded part directly under the right clamp 6r becomes the austenite phase, and the unit 6
It moves to the right as the r part moves.

(4) Once the forces are balanced, clamp with the left clamp 6Q.

By repeating the cycles (1) to (4) above,
The drive unit 4 moves to the right relative to the shape memory alloy 1. Conversely, if the right switches 8Q2, 8r, etc. are used instead of the left switches 8Q, 1°8r□, it will move to the left.

In the above explanation, the shape memory alloy is heated by electricity and cooled naturally, but it is not limited to these methods, and various heating and cooling methods, such as induction heating, can be used.

It is also possible to use a combination of a ceramic heater, etc., oil cooling, forced air cooling, Peltier element, etc.

(Effects) A pair of clamp mechanisms that clamp the shape memory alloy, and feeders provided asymmetrically on both sides of each clamp mechanism,
It consists of a drive unit consisting of a power supply and a switch that feeds power to each feeder, and by alternately controlling the drive unit and clamp mechanism, inchworm operation can be performed effectively.

This mechanism made it possible to obtain an inchworm actuator with a large displacement.

[Brief explanation of drawings]

FIG. 1 is a conceptual diagram of the present invention. Figure 2 is a detailed diagram of the Odo Units 1. FIG. 3 is an explanatory diagram of the operation. In the figure; 1 Shape memory alloy 3 Linear guide 5　Electron feeder 7 Power supply 9 Spring mobile unit Rotating Units 1~ clamp mechanism switch I"2

Claims (2)

[Claims] (1) A drive unit consisting of a pair of clamp mechanisms that clamp the shape memory alloy, feeders provided asymmetrically on both sides of each clamp mechanism, a power source and a switch for feeding power to each feeder, and the drive unit described above. An inchworm mechanism using a shape memory alloy, comprising a control device that alternately operates a unit and a clamp mechanism. (2) Claim (2) characterized in that two pairs of feeders are provided asymmetrically on both sides of the clamp mechanism to enable movement in opposite directions.
An inchworm mechanism using the shape memory alloy described in item 1).