JPS59219828A - Temperature sensitive switch unit - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a temperature-sensitive switch device that detects temperature changes within electrical equipment and opens and closes electrical circuits.

Conventional devices of this type use bimetal as the temperature sensing element, but bimetal has a small operating force during operation and is difficult to miniaturize, so it can be used by incorporating it into the coil of a motor, for example. There wasn't.

The present invention aims to provide a temperature-sensitive switch device that can solve these problems.

The temperature-sensitive switch device of the present invention will be explained below with reference to the accompanying drawings. In FIG. 1, reference numeral 10 denotes an exterior body which includes a switch mechanism 20 therein and is constructed to include connection terminals 11, 11, . . . .

The switch mechanism 2o includes a temperature sensing element made of a shape memory alloy, for example, a temperature sensing wound body 30 in the shape of a coil spring.
A bias element, such as a bias spring 40, which acts to suppress the operation of the temperature-sensitive wound body 30 is provided.

The switch mechanism 20 has a required number of switch parts 21, for example, three in the case of a three-phase AC motor, and the switch part 21 has fixed contacts 21 provided on the stator 22.
1 and a movable contact 212 provided on the movable element 23, and each of the contacts 211 and 212 is connected to the terminal 11, respectively.

The temperature-sensitive winding body 30 of the temperature-sensing element part embodiment is preliminarily memorized with an operating shape due to abnormal temperatures, and is also set to have a resting shape, which is opposite to the operating shape, at a steady temperature. The switch section 21 is set to be in a steady state when it is in the resting shape, and is set to be switched to an abnormal state opposite to the steady state when it is in the operating shape.

In the embodiment, the temperature-sensitive wound body 30 is made of a two-way memory alloy so that it expands when the temperature rises and contracts when the temperature falls, and the switch section 21 is configured to close the circuit in a steady state. is interposed between the movable element 23 and the stator 22.

The bias spring 40 is made in a coil shape, and pushes the movable element 23 downward in the figure to push the switch part 2
One movable contact 212 is brought into contact with the fixed contact 211.

Therefore, in the device of this embodiment, electricity is applied during normal times, and when the temperature rises, the temperature-sensitive wound body 30 expands and pushes the movable element 23 upward in the figure against the bias spring 40. It operates to open the switch section 21.

The safety switch device constructed in this way is used by being inserted into the electromagnetic coils 51, 52 and 53 of a motor, as shown in FIG. 2, for example.

In this case, the temperature-sensitive wound body 30 is connected to the coils 51 and 52°5.
If the temperature of the Joule heat generated when an overcurrent flows through the motor 3 is set so that the temperature-sensitive winding body 30 expands, the switch part 21 will expand when an abnormality occurs in the motor.
Because it opens between the contacts.

The motor can be stopped in the event of an abnormality.

In the above, the temperature-sensitive wound body 3 as the temperature-sensitive element
0 is made of a two-way memory alloy as in the embodiment, when the temperature of the electromagnetic coils 51, 52, and 53 returns to normal temperature, the temperature-sensitive winding body 30 contracts and the switch part 21 is closed again. Therefore, the motor will automatically resume operation, but in some cases, the temperature sensing element may be made of a one-way memory alloy.In this way, when an abnormal situation occurs, the motor that has stopped will be able to resume its operation. It is possible to maintain the condition.

Furthermore, the device of the present invention can be used in other electrical equipment to detect abnormalities caused by heat; for example, it can be used as a detection means for fire alarms and hot air devices. For example, if a heater for control is attached, it is possible to operate by the heat generated from the heater.

The above-mentioned temperature sensing element may be used for other purposes in normal times, and in the embodiment, the temperature sensing wound body 30 is
If used for maintaining the posture in step 3, the bias spring 40 can be omitted.

Since the switch device of the present invention is as described above, the following effects can be expected.

Since the force of shape memory alloys to return to their memorized shape is much greater than that of bimetals, it is possible to obtain a large operating force, and since the temperature sensing element can be made small, the entire device can be downsized.

Since the shape memory alloy has good formability, it is possible to easily make a temperature sensing element in the shape of a coil spring as in the embodiment, or in other shapes.

Therefore, the temperature sensing element can also be used for other purposes as a component of the device during normal use.

Temperature-sensitive elements using shape memory alloys have extremely accurate response to temperature, so malfunctions can be prevented by strictly setting the operating temperature range.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional front view of the device of the present invention, and FIG. 2 is a schematic diagram showing an example of use of the same device. In the figure, 10 is an exterior body, 20 is a switch mechanism, 21 is a switch section, and 30 is a temperature-sensitive wound body as a temperature-sensing element. 40 indicates a bias spring.

Claims (1)

[Claims] 1. A switch mechanism having a required number of switch parts is provided in the exterior body, and a temperature sensing element made of a shape memory alloy is attached to the switch part, and the temperature sensing element has a predetermined temperature. The operating shape is memorized by temperature, and the switch section is set to have a resting shape different from the operating shape under normal conditions, and the switch section is set to the normal state when the temperature sensing element assumes the resting shape. A temperature-sensitive switch device characterized in that, when the temperature-sensing element exhibits an operating shape when a force is applied, the change in shape causes the temperature-sensitive element to be switched to an abnormal state. 2. The switch section is configured to be closed in a normal state and opened in an abnormal state, and a pair of contacts constituting the switch section are provided on the stator and mover, respectively, and the temperature sensing element is 2. The temperature-sensitive switch device according to claim 1, wherein the temperature-sensitive switch device is made in the shape of a coil spring and is interposed between the stator and the movable element.