JP2743512B2 - Thermal protector - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermal protector that is used in various electric equipment and protects the electric equipment from burning due to abnormal heat generation and overcurrent.

2. Description of the Related Art Conventionally, this type of thermal protector has a structure in which a mount body in which a movable-side electrode and a fixed-side electrode are fixed to face each other is housed in a container. And such a thermal protector is attached to a heating part of various electric devices,
When the temperature of that part rises due to some abnormality or an overcurrent flows, the snap-action type thermo-responsive element of the movable side electrode reverses, and the element moves away from the fixed side electrode and moves to the electrical equipment. It has a protection function to cut off the current.

Problems to be Solved by the Invention This type of thermal protector is required to be able to withstand a large current, particularly when used in a motor, a fluorescent lamp stabilizer or the like. However, if it is miniaturized with such a structure,
Since the volume of the container is reduced, the internal pressure of the container increases due to the arc heat caused by the intense arc between contacts when energizing at a large current, and it is not possible to prevent the container from being damaged and igniting outside the container. There were serious disadvantages.

The present invention has been made in order to solve such a problem associated with a small-sized structure, and a small-sized thermal protector with high safety that does not cause ignition or the like even when used in a motor or a fluorescent lamp stabilizer. To provide.

Means for Solving the Problems A thermal protector according to the present invention has a movable side in which one end of a metal plate is connected to one end of a snap action type thermoresponsive element, and a movable electrode lead wire is connected to the other end of the metal plate. An electrode and a mount body provided with the fixed side electrode facing each other are housed in a container, the metal plate is made of a soluble metal, and has a cutout on at least one side on the snap action type thermoresponsive element side. I have.

In the present invention, when a large current flows through the thermal protector, the cutout portion of the soluble metal plate is instantaneously melted or deformed by softening, so that the contact portion is opened and cuts off the power supply to the thermal protector.

Embodiment Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

As shown in FIGS. 1 and 2, a thermal protector according to an embodiment of the present invention has a snap-action type thermoresponsive element 2 having a contact 1 welded to the tip, and one end at one end of the snap-action type thermoresponsive element. A metal plate 3 made of a soluble metal with a welded portion, and a movable electrode 5 made of a movable electrode lead wire 4 welded to the other end of the metal plate;
A bead 9 made of glass or resin is opposed to a fixed electrode 8 consisting of a fixed electrode lead wire 7 having a contact 6 welded to the tip so as to cross-contact with the contact 1 at a predetermined contact pressure.
The integrated mount body 10 is housed in a container 11 made of glass or resin, and the opening of the container is sealed with a filler 12 made of a heat-hardening type flame-retardant silicone rubber or epoxy resin. I have. The metal plate 3 is made of, for example, Monel metal, and has notches 3a on both sides on the side of the snap-action type thermoresponsive element.

When a large current flows through the thermal protector having the above configuration, the cutout 3a of the metal plate 3 is instantaneously deformed by fusing or softening. The contact 1 is separated, and the power supply to the thermal protector is cut off. Therefore, according to this thermal protector, it is possible to prevent ignition outside the container 11 due to a strong arc generated between the contacts 1 and 6.

Note that the entire metal plate cannot be formed so thin. That is, if the entire metal plate is formed with the width of the notch,
The workability of welding the metal plate and the lead wire of the movable electrode becomes extremely poor. However, as in the present invention, if a notch is provided on at least one side of the metal plate, the intended purpose can be achieved while maintaining the welding workability in a good condition.

Based on the above embodiment, a small thermal protector (product of the present invention) having dimensions as shown in Table 1 was manufactured.
When the short circuit test of AC125V ~ 250V200A was performed,
The results as shown in the table were obtained. In Table 1, the conventional product has the structure described in the related art, and in Table 2, the comparative product has the same structure as that of the conventional example.
85mm, total length 18mm).

As is evident from Tables 1 and 2, the product of the present invention can be completely prevented from igniting outside the container in the above test, even though it is a small product whose volume ratio is 40% smaller than the conventional product. Change.

In the above embodiment, an example in which notches are provided on both sides as metal plates has been described, but the notches may be provided on one side as shown in FIG. 3A. Further, the metal plate may have a shape as shown in FIGS. 3B and 3C.

Effect of the Invention As described above, the present invention connects a movable electrode to which one end of a metal plate is connected to one end of a snap action type thermoresponsive element, and a movable electrode lead wire is connected to the other end of the metal plate. Since the mount body provided with the fixed electrode facing the housing is housed in a container, the metal plate is made of a soluble metal, and has a cutout on at least one side on the snap action type thermal response element side. In addition, since the occurrence of arcs between the contacts at the time of energization with a large current can be prevented, it is possible to provide a very safe and small thermal protector that can avoid ignition to the outside of the container.

[Brief description of the drawings]

FIG. 1 is a partially cutaway front view of a thermal protector according to an embodiment of the present invention, FIG. 2 is a perspective view of a mount body of the thermal protector, and FIGS. It is a perspective view showing an example. 1 contact point 2 snap action type thermo-responsive element
3 ... Metal plate, 4 ... Movable electrode lead wire, 5 ... Movable electrode, 6 ... Contact, 7 ... Fixed electrode lead wire, 8 ... Fixed electrode, 9 ... Bead, 10 ... Mount Body, 11 ... container, 12 ... filler.

Claims (1)

(57) [Claims] An end of a metal plate is connected to one end of a snap action type thermoresponsive element, and a movable electrode having a movable electrode lead wire connected to the other end of the metal plate is opposed to a fixed electrode. A thermal protector characterized in that the mount body provided as above is housed in a container, the metal plate is made of a soluble metal, and has a cutout on at least one side on the side of the snap-action type thermally responsive element.