JPH04167321A - Thermally-actuated switch - Google Patents

Abstract

PURPOSE:To facilitate downsizing of a switch by providing a shape memory alloy spring which is deformed into a previously memorized shape at a prescribed temperature for energizing a second conductor in the separating direction from a first conductor and a balance spring. CONSTITUTION:A shape memory alloy spring 3 is not deformed in its shape to keep a state shown in the figure as long as ambient temperature is lower than a prescribed temperature, therefore, a switch is in an ON state. When the ambient temperature exceeds the prescribed temperature, the spring 3 is contracted due to an effect of a metal phase transformation process, and a second conductor 2 connected thereto is thereby drawn to the right side to be moved against tensile force of a balance spring 4 for separation from a conductor 1. Therefore, the switch becomes OFF. When the ambient temperature again becomes lower than the prescribed temperature, the spring 3 returns from the contraction state and the conductor 2 is drawn by the tensile force of the spring 4 to be moved to the left and brought into contact with the conductor 1. Therefore, the switch again becomes ON.

Description

[Detailed description of the invention] (Industrial application field) This invention relates to a thermally responsive switch.

More specifically, it relates to improvements in switches such as thermostats that utilize the thermal deformability of shape memory alloys.

(Prior Art) Conventionally, a thermostat using a shape memory alloy as a member that senses the temperature change and operates a conductor contact when the outside temperature or the temperature of equipment deviates from a set value is disclosed in, for example, Utility Model Application Publication No. 1-1- It is already known from No. 174834 and the like.

(Problems to be Solved by the Invention) All of these conventional switches using shape memory alloys are configured to move the on/off mechanism between the conductor contacts in the vertical direction. For this reason, it is necessary to secure space between the conductors for vertical movement, which has been an obstacle to miniaturization of the switch.

Also, in the case of an on/off mechanism that moves in the vertical direction.

Static electricity attracted dust from the surrounding area, often resulting in contact failure.

An object of the present invention is to eliminate the various disadvantages inherent in the above-mentioned on/off mechanism using vertical movement.

(Means for Solving the Problem) According to the present invention, the first conductor (1) has one end fixed, and the other end is movable in the horizontal direction and the other end can be contacted with the other end of the first conductor. The provided second conductor (2) is fixed at one end and connected to one end of the second conductor at the other end, and deforms into a pre-memorized shape at a set temperature to transform the second conductor into the first conductor. a shape memory alloy spring (3) that is biased in a direction away from the second conductor; A thermally responsive switch having a bias spring (4) that is always pressed and biased is obtained.

That is, in the ninth invention, the conductor contacts are moved in the horizontal direction using a shape memory alloy to turn on and off.

(Function) Due to the interaction between the shape memory alloy spring attached to the conductor and the bias spring, the conductor moves in the horizontal direction and comes into contact with and separates from the conductor.

(Example) FIG. 1 shows an example of a thermally responsive switch of the present invention. Note that the figure shows a state when the environmental temperature is lower than the set temperature.

A first conductor 1 is fixed at one end onto a stand 6 provided on the floor of an aluminum case 5. The conductor 1 has a tapered shape from one end to the other end as shown in the figure.

The second conductor 2 has its other end in contact with the other end of the first conductor l as shown in the figure, and one end thereof is provided so as to be movable in the horizontal direction. Although not particularly shown in the drawings, in order to guide the movement of the second conductor 2 in the horizontal direction, the case 5 is preferably provided with an appropriate guide or the like that engages with the second conductor 2.

One end of this second conductor 2 is connected to the other end of a spring 3 made of a shape memory alloy. Further, one end of this spring 3 is fixed to the case 5. This shape memory alloy spring 3 deforms into a pre-memorized shape when the set temperature is reached. In the case of this invention, a metal phase transformation treatment is performed so that the shape contracts when the environmental temperature exceeds a set temperature.

Similarly, the other end of a bias spring 4 is connected to one end of the second reception member 2, and this always presses the second conductor 2 toward the shape memory alloy spring 3.

Next, the effect will be explained.

First, as long as the environmental temperature is lower than the set temperature, the shape memory alloy spring 3 does not change its shape and maintains the state shown in FIG. 1.

In other words, the switch is in an on state.

When the environmental temperature exceeds the set temperature, the shape memory alloy spring 3 contracts due to the effect of the metal phase transformation treatment described above. Then, the second conductor 2 connected thereto is pulled to the right in the figure, moves against the tensile force of the balance spring 4, and is separated from the first conductor 1. In other words, the switch is turned off.

When the environmental temperature becomes lower than the set temperature again, the shape memory alloy spring 3 returns from the contracted state, and the second conductor 2 is pulled by the tensile force of the balance spring 4 and moves to the left in the figure, so that the first conductor 1 come into contact with. In other words, the switch is turned on again.

(Effects of the invention) Since the conductor moves horizontally using a shape memory alloy, there is no need to secure vertical space.

It becomes easy to downsize the switch. In addition, dust and the like that are attracted to the movable contact due to the horizontal movement are removed by friction with related members, thereby reducing the number of contact failures.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional side view showing the switch of the present invention in an on state, and FIG. 2 is a cross-sectional side view showing the switch in an off state. DESCRIPTION OF SYMBOLS 1... First conductor, 2... Second conductor, 3... Shape memory alloy spring, 4... Nokuransu no kune. Figure 1 Figure 2

Claims (1)

[Claims] 1. A first conductor (1) with one end fixed, and a second conductor with one end movable in the horizontal direction and the other end provided so as to be able to contact the other end of the first conductor. (2) fixed at one end and connected to one end of the second conductor at the other end, deformed into a pre-memorized shape at a set temperature and biased in a direction to separate the second conductor from the first conductor; a shape memory alloy spring (3) that is fixed at one end and connected to one end of the second conductor at the other end, and a bias spring that constantly presses and urges the second conductor in the direction of contacting the first conductor. (4) A thermally responsive switch comprising: