JPS644069B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a heat sensitive pressurizing device using a shape memory alloy as an actuator.

When a plurality of members made of different materials are bonded using a thermosetting adhesive, when the temperature rises during bonding, distortion occurs due to mutually different coefficients of thermal expansion, resulting in poor bonding. Therefore, if we use a clamp made of shape memory alloy and start applying pressure for bonding when the temperature reaches approximately 100℃ during bonding, approximately 50% of the strain caused by thermal expansion will be removed and the defective rate will be significantly reduced. reduce

Incidentally, various types of heat-sensitive devices have been developed that use shape memory alloys as actuators and perform operations according to temperature beyond the transformation point. However, since shape memory alloys are considerably more expensive than spring steel, etc., the use of a large number of materials in order to obtain sufficient output as an actuator results in extremely high prices. Therefore, although products using shape memory alloys have excellent thermal response characteristics, cost problems are a major obstacle to their practical application.

The present invention has been made based on the above circumstances, and its purpose is to provide a heat-sensitive actuator that can obtain the necessary output even with a small amount of shape memory alloy and contribute to cost reduction. The purpose of the present invention is to provide a pressurizing device.

That is, the present invention includes a frame, a pressure member provided on the frame so as to be movable back and forth, and a substantially V-shaped frame having one end pivotally connected to the frame and the other end connected to the pressure member. a booster link, a shape memory spring that urges the booster link in either the pressurizing direction or the non-pressurizing direction of the pressure member in the austenite phase when the temperature exceeds a predetermined temperature; The heat-sensitive pressurizing device is characterized by comprising a shape memory spring that displaces the boosting link against the elastic force of the shape memory spring when the temperature of the memory spring is below a predetermined temperature.

A first embodiment of the present invention will be described below with reference to FIG. In FIG. 1, 1 is a frame made of metal or synthetic resin,
This frame 1 includes a base 2 and a side plate 4 fixed to the base 2 using fixing devices 3 such as bolts.
It consists of At one end side of the base 2, there is approximately a T.
A letter-shaped end portion 5 is formed. This end 5
has a through hole 6 for inserting the mounting bolt.
and an adjustment member 7 are provided. The adjusting member 7 consists of an adjusting screw 9 having a support portion 8 on its end surface and a lock nut 10. The adjusting screw 9 is screwed into the screw hole 11 formed in the end portion 5, and by changing the amount of screwing, the distance l to the pressure member 17, which will be described later, can be changed. It's summery.

Further, a slide guide 15 is attached to the frame 1 at a position on the end portion 5 side by a fixture 16. And this slide guide 15
A rod-shaped pressure member 17 is provided so as to be movable toward and away from the support portion 8 . The pressure member 17 and the adjustment member 7 constitute a clamp portion 18.

Note that the adjustment member 7 may be provided on the pressure member 17 side.

Further, the frame 1 is provided with a booster link 20. This booster link 20 has a first link member 21 and a second link member 22 connected by a pivot 23 to form a substantially V-shape. One end of the booster link 20 is pivotally connected to the frame 1 by a shaft 24, and the other end is pivotally connected to the frame 1 by a shaft 25.
It is connected to the pressure member 17 by.

Further, the second link member 22 is formed with an arm portion 26 extending laterally, and a bias spring 30 is stretched between the arm portion 26 and a locking portion 27 provided on the frame 1. has been done. The bias spring 30 may be a conventional tension coil spring made of spring steel. The bias spring 30 always pushes the booster link 20 onto the pressure member 17.
The pressure member 17 is biased in the non-pressurizing direction, that is, in the direction in which the pressure member 17 is separated from the support portion 8 .

Further, a shape memory spring 32 is stretched between an intermediate portion of the booster link 20, for example, a locking portion 31 provided on the first link member 21 and a locking portion 27 provided on the frame. This shape memory spring 32
is made of Ti-Ni alloy and other shape memory alloys,
During the so-called cooling phase, which is below the transformation point, it expands against the repulsive force of the bias spring 30, and in the temperature range above the transformation point, martensitic reverse transformation occurs and the coil becomes an austenite phase, thereby shortening the free length of the coil. It has a shape memory effect. In this austenite phase, the output is set to overcome the repulsive force of the bias spring 30 and move the booster link 20 in the direction in which the pressure member 17 is pressed, that is, in the direction in which it approaches the support portion 8. .

In the first embodiment configured as described above, the shape memory spring 32 is in the martensitic phase when it is cold below the transformation point, and the repulsive force is small. Therefore, the biasing force of the bias spring 30 is overcome, and the booster link 20 receives a torque in the direction in which its opening angle θ becomes narrower, and the shaft 2
The distance between 4 and 25 becomes smaller. Therefore, since the distance l between the pressure member 17 and the support part 8 increases,
For example, a rotating plate-shaped non-clamped object A can be placed in a non-pressurized state.

On the other hand, when the ambient temperature near the shape memory spring 32 rises and reaches a temperature exceeding the transformation point, the shape memory spring 32 reversely transforms into an austenite phase, thereby exhibiting an elastic restoring force several times higher than that of the martensitic phase. As a result, the force that draws the booster link 20 toward the locking portion 27 becomes large. That is, the booster link 20 is displaced in the direction in which the opening angle θ increases, and θ becomes approximately
Since the angle approaches 180°, even if the tensile force (output) by the shape memory spring 32 is small, the force can be increased several to several tens of times to move the pressure member 17 toward the support portion 8, and the pressure member 17 can be moved toward the support portion 8 without being clamped. Object A can be pressurized.

More specifically, in Fig. 2, the acting force F required to obtain a predetermined output P is expressed as F=2Psinα/cosα, and α rotates back and forth at an angle of _α1 to _α2 . The stroke ST in this case is expressed as ST=2L(cosα ₁ −cosα ₂ )...

Therefore, in the case of reciprocating rotation at an angle of α ₁ = 1° and α ₂ = 15°, in order to generate an output of pressurizing force P = 10 Kg at α ₁ = 1°, F = 0.349 Kg using the above formula. That would be enough. Furthermore, if H=18.9mm, the stroke ST will be approximately 4.5mm. Then, when the load is corrected depending on the mounting position of the shape memory spring 32, the spring size becomes wire diameter α = 1.0 mm, average coil diameter D = 10 mm, effective number of turns N = 12, and the spring unit weight is approximately 2.2 g. .

On the other hand, a general heat-sensitive pressurizing device that does not use a booster link (see Figure 3), which uses the repulsive force of a shape memory spring as a direct pressurizing force, is equivalent to this example. To obtain pressurizing force, d=3.6mm, D=
22mm, N=4.5, spring unit weight 29.7g is required. In other words, according to this example, the weight of the shape memory alloy material is reduced by 93%, which is extremely effective in terms of cost and weight. In the conventional device shown in FIG. 3, a indicates a shape memory spring, b a bias spring, and c a clamp portion.

Note that FIG. 4 shows a second embodiment of the present invention, and since the basic configuration is almost the same as the first embodiment, common parts are given the same reference numerals and explanations are omitted, and different parts are will be explained below.

That is, in the case of this second embodiment, the pressure member 17
is in the shape of a lever that reciprocates around the shaft 35, and the tip end surface 17a of this pressure member 17 is connected to the support portion 8.
is facing. One end of the second link member 22 is connected to a shaft 25 provided on a part of the pressure member 17, and an arm portion 26 is provided on the first link member 21, and a locking portion between this arm portion 26 and the frame. A bias spring 30 is stretched between the terminal and the terminal 27.

In the second embodiment having the above configuration, when the temperature rises above the transformation point of the shape memory spring 32, the shape restoring force of the shape memory spring 32 overcomes the bias spring 30, as in the first embodiment, and the booster link 20 Opening angle θ
By pulling the pressure member 17 in a direction closer to 180°, the end surface 17a of the pressure member 17 can be displaced toward the support portion 8 side. Also in this case, the pressure member 17 can be driven by increasing the slight force exerted by the shape memory spring 32. Therefore, the shape memory spring 32
If the amount of material used is at least (specifically, even if a shape memory spring with a small wire diameter or a small shape memory spring is used), a large pressing force can be obtained.

Further, according to the second embodiment, since the pressure member 17 rotates around the shaft 35, the width of the entire device, that is, the horizontal dimension in FIG. 4, is smaller than that of the first embodiment. It can be made smaller and more compact.

Note that the bias spring may be locked at a location other than the locking portion 27 and the arm portion 26, as long as the booster link can always be biased in the non-pressurizing direction of the pressure member. . Further, the shape memory spring 32 may be stretched between the pivot 23 and the locking portion 27.

Further, in each of the above embodiments, the pressure is generated at high temperatures, but the present invention is not limited to this. For example, by completely reversing the mounting position of the shape memory spring 32 and the bias spring 30, it is possible to generate pressure at low temperatures. A pressurizing force may be applied at times. That is, in the case of FIG. 1 or 4, a bias spring 30 is stretched between the locking portions 27 and 31, and a shape memory spring 32 is stretched between the arm portion 26 and the locking portion 27. In this way, when the temperature is low, the elastic force of the bias spring moves the booster link 20 in the direction of pressing the pressure member 17, and when the temperature is high, the bias spring repulses due to the shape recovery force of the shape memory spring. The pressurizing member 17 can be displaced in the non-pressurizing direction against the force to release the pressurizing force.

Furthermore, in the case of FIG. 1 or 4, a compression coil spring type shape memory spring is interposed between the parts corresponding to the locking parts 27 and 31 instead of the tension coil spring type shape memory spring 32. By providing the pressure member 17, the pressure member 17 may be displaced in the non-pressure direction when the temperature is high.

In addition to the above-mentioned application as a clamp, the present invention can also be used in a positioning device, a brake device, a cutting device, etc. that simply utilizes pressing force.

As explained above, according to the present invention, even if the output of the shape memory spring is small, the pressurizing force can be increased by the booster link to drive the pressurizing member, so that an expensive shape memory alloy material is used. Quantity can be saved. This is an extremely useful invention as it enables practical use of shape memory alloys as actuators due to cost reduction.

[Brief explanation of drawings]

Fig. 1 is a side view of a heat-sensitive pressurizing device showing a first embodiment of the present invention, Fig. 2 is a schematic diagram showing the relationship between dimensions and angles of the booster link, and Fig. 3 is a conventional shape memory spring. FIG. 4 is a side view, partially in cross section, of a second embodiment of the present invention. DESCRIPTION OF SYMBOLS 1... Frame, 7... Adjustment member, 17... Pressure member, 18... Clamp part, 20... Boosting link, 21... First link member, 22... Second link member, 30... Bias spring, 32...Shape memory spring.

Claims (1)

[Claims] 1 a frame, a pressure member provided on the frame so as to be movable back and forth, and a booster link having a substantially V-shape and having one end pivotally connected to the frame and the other end connected to the pressure member. , a shape memory spring that biases the booster link in either the pressurizing direction or the non-pressurizing direction of the pressurizing member in the austenite phase when a predetermined temperature is exceeded; and a bias spring that displaces the boosting link against the elastic force of the shape memory spring when the temperature is below .