JPH03176926A - Thermal protector - Google Patents

Abstract

PURPOSE:To prevent the ignition to the outside of a container by the breakage of the container by forming a constriction section with a current fuse function and hooking holes on a part of a moving electrode plate or a fixed electrode plate, and burying them in an insulating block. CONSTITUTION:When a large current is fed to a thermal protector, a constriction section 12c provided on a moving electrode plate 12 is melted. The occurrence of an intense arc across a moving contact 2 and a fixed contact 6 can be prevented, the constriction section 12c is buried in an insulating block 9, and an arc generated across one end section 12a and the other end section 12b when the constriction section 12c is melted can be sealed by the insulating block 9. Even if the moving electrode plate 12 is removed from the insulating block 9 by the arc and the arc breaks the container 10 and goes out of the container 10, the moving electrode plate 12 is hooked on the insulating block 9 by hooking holes 12e, 12f provided on the wide section 12d of the moving electrode plate 12, thus the removal of the moving electrode plate 12 can be prevented, and the ignition to the outside of the container 10 can be avoided.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention is used in various electrical equipment, such as motors or fluorescent lamp ballasts, and is used as a thermal protector to prevent burnout of electrical equipment due to abnormal heat generation and excessive current. , especially regarding small thermal protectors.

Conventional technology Conventionally, a small thermal protector is shown in Fig. 2 fal+b+
It has the configuration shown in . That is, a movable electrode body is formed by welding an inverted trimetal 3 with a movable contact 2 welded to its tip to one end 1a of a movable electrode plate 1, and a fixed electrode plate includes a contact plate 7 with a fixed contact 6 welded to its tip. A fixed electrode body formed by welding to one end 5a of 5,
A movable contact 2 and a fixed contact 6 are provided facing each other so as to be in contact with each other with a predetermined contact pressure, and the movable electrode plate 1 and the fixed electrode plate 5 are fixedly supported by being embedded in an insulating block 9 made of resin at approximately the center thereof. The movable covered lead wire 4 is welded to the other end 1b of the movable electrode plate 1, and the fixed covered lead wire 8 is welded to the other end 5b of the fixed electrode plate 5 to form a mount body. This mount body is housed in a container 10 made of resin having an opening at one end, and the movable covered lead wire 4 and the fixed covered lead wire 8 are passed through the opening of the container 10.
The opening of the container 10 is filled with a filler 11 made of resin.
It is sealed in.

The thermal protector having such a configuration is attached to a motor, etc., and in response to an abnormal temperature rise and excessive current, the reversible trimetal 3 performs an inverting return operation.
It has the function of opening and closing the movable contact 2 and fixed contact 6 to prevent burnout of the motor, etc.

Problems to be Solved by the Invention This type of thermal protector must be able to withstand large currents, especially when used in motors, fluorescent lamp ballasts, and the like. However, when this structure is miniaturized, the volume of the container becomes smaller, and as a result, the internal pressure of the container increases due to the arc heat caused by the intense arc between the contacts when energizing at a large current, causing the container to break and cause the container to leak out. The major drawback was that it was impossible to prevent the fire from igniting.

The present invention was made to solve these problems associated with a compact structure, and provides a highly safe compact thermal protector that will not cause a fire when used in motors, fluorescent lamp ballasts, etc. This is what we provide.

Means for Solving the Problems The thermal protector of the present invention is provided with a movable electrode body having a movable electrode plate and a fixed electrode body having a fixed electrode plate facing each other, and wherein the movable electrode plate and the fixed electrode A mount body in which the plate is integrated with an insulating block is housed in a container, and at least one of the movable electrode plate and the fixed electrode plate has a constricted portion having a current fuse function, and a wide constricted portion following the constricted portion. A locking hole is formed in the part, and the constricted part and the hole are embedded in the insulating block.

Function: According to the present invention, when a large current flows through the thermal protector, the constricted portion having a current fuse function melts, thereby preventing the occurrence of intense arcing between the contacts. However, when the constriction is fused, an explosive arc is generated between both ends of the electrode plate where the constriction is formed. However, this arc is contained by an insulating block. In addition, in rare cases, the arc may cause the electrode plate to be pulled out of the insulating block, causing the arc to exit the container. Since it is locked to the insulating block, there is no need to remove the electrode plate. As a result, ignition outside the container can be prevented.

EXAMPLE Hereinafter, an example of the present invention will be described with reference to the drawings.

As shown in FIGS. 1(a) and (bl), the thermal protector according to the embodiment of the present invention has a snap-action type thermally-responsive element made of an inverted trimetal 3 with a movable contact 2 welded to the tip in the center part. Neck part 12c with hinnies function
A movable electrode body is formed by welding to one end 12a of a movable electrode plate 12 provided with a fixed electrode body, and a fixed electrode body is formed by welding a contact plate 7, which has a fixed contact 6 welded to its tip, to one end 5a of a fixed electrode plate 5. are provided facing each other so that the movable contact 2 and the fixed contact 6 are in contact with each other with a predetermined contact pressure.

Approximately central portions of the movable electrode plate 12 and the fixed electrode plate 5 are embedded and integrated in an insulating block 9 made of resin. In this case, a constricted portion 12c having a current fuse function is provided in the center of the movable electrode plate 12, and a locking hole 12e is provided in a wide portion i-2d following the constricted portion 12c.
, 12f are provided, and the constricted portion and the locking hole are buried in the resin block 9 so as to be located in the center thereof.

The movable covered lead wire 4 is welded to the other end 121 of the movable electrode plate 12, and the fixed covered lead wire 8 is welded to the other end 5b of the fixed electrode plate 5. The mount body is constructed as described above. This mount body is a container 1 made of resin with an opening at one end and has a length of 16.4 mm, a width of 6.0 mm, and a thickness of 3.1 mm.
The movable covered lead wire 4 and the fixed covered lead wire 8 are led out from the opening of the container 10, and the opening of the container 10 is sealed with a filler 11 made of epoxy resin or the like. .

In such a thermal protector, for example, 200A
When a large current of , is buried in the insulating block 9, so that the insulating block 9 can confine the arc generated between the one end 12a and the other end 12b when the constriction], 2c is fused. In addition, although it is rare, the arc may cause the movable electrode plate 12 to be pulled out from the insulating block 9, and the arc may break through the container 10 and exit the container. Since the movable electrode plate 12 is locked to the insulating block 9 through the provided locking holes 12e and 12f, it is possible to prevent the movable electrode plate 12 from being pulled out and to avoid ignition outside the container.

Furthermore, this thermal protector does not require the addition of any new parts and does not require any changes in the assembly process, so it can be obtained at low cost.

In addition, in the above embodiment, a case was explained in which a constricted portion having a current fuse function was provided on the movable electrode plate.
Of course, the constricted portion may be provided on the fixed electrode plate, or may be provided on both plates.

DETAILED DESCRIPTION OF THE INVENTION As described in detail, the present invention provides a movable electrode body having a movable electrode plate and a fixed electrode body having a fixed electrode plate facing each other, and wherein the movable electrode plate and the fixed electrode plate A mount body integrated with an insulating flock is housed in a container, and at least one of the movable electrode plate and the fixed electrode plate has a constricted portion having a current fuse function, and a wide portion following this constricted portion. A locking hole is formed, and the constriction and the locking hole are buried in the insulating block, so that when a large current is applied, the constriction of the electrode plate melts and arcs between the contacts are prevented. In addition, the arc that occurs between both ends of the electrode plate when the constriction melts is contained by the insulating block, and the fused electrode plate is locked to the insulating block by the locking hole provided in the electrode plate. By doing so, it is possible to prevent the electrode plate from being pulled out, which prevents the arc from exiting the container, which is extremely safe as it can reliably avoid ignition outside the container. Providing a small thermal protector at low cost] Figure 1 (al and fbl are a partially cutaway front view and side view of a thermal protector according to an embodiment of the present invention;
Figures (al and bl) are a partially cutaway front view and a side view of a conventional thermal protector.

2...Movable contact, 2...Trimetal,
5...Fixed electrode plate, 6...Fixed contact, 9...Insulating flock, 10...
Container, 12...Movable electrode plate, 12c...
...Narrow part, 12d...Wide part, 1.2
e, 12f...Hole for locking.

Claims (1)

[Claims] A mount body in which a movable electrode body having a movable electrode plate and a fixed electrode body having a fixed electrode plate are provided facing each other, and the movable electrode plate and the fixed electrode plate are integrated with an insulating block is placed in a container. a constricted portion having a current fuse function in a portion of at least one of the movable electrode plate and the fixed electrode plate, and a locking hole formed in a wide portion following the constricted portion; and the hole is embedded in the insulating block.