JP3136966B2 - Thermal protector and method of manufacturing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a normally closed contact type self-recovering thermal protector and a method of manufacturing the same.

[0002]

2. Description of the Related Art Such a thermal protector comprises a movable electrode having a movable element such as a direct-heated or indirectly-heated bimetal or the like as a movable piece, and a fixed electrode constituting a normally closed contact type switch together with the movable electrode. Connected to the electrical equipment to protect the electrical equipment.

In other words, a thermal protector connected to a power supply circuit of an electric device has a switch contact by a bending action of a thermally responsive element only when an excessive current flows through the electric device or when an ambient temperature becomes abnormally high. , The power supply to the electric device is cut off. Then, the switch contact that has automatically returned due to the temperature drop due to the cutoff of the power supply restarts the power supply, which not only helps to prevent danger but also allows the electric device to always operate in a predetermined temperature range.
In addition, it is possible to notify an abnormality of the electric device.

[0004]

SUMMARY OF THE INVENTION The present invention can further improve the safety of a conventional thermal protector and has a function of interrupting an excessive current even when the switch contacts are fused. An object of the present invention is to provide a thermal protector and a method of manufacturing the same.

[0005]

Means for Solving the Problems] thermal protector of the present invention, have a fixed contact point to an end, and the fixed contact is
In a thermal protector having a fixed electrode whose only end on the opposite side is fixed, and a movable electrode having a movable contact at the end, which is deformed by heating and comes into contact with and separates from the fixed electrode, the fixed electrode is A plurality of electrode plates are fixed to each other in the longitudinal direction via a soluble metal portion, and a boundary surface of the electrode plate fixed to the soluble metal has an inclined shape.

Further, according to the method of manufacturing a thermal protector of the present invention, after a band-shaped fixed contact material is formed in the longitudinal direction of the metal plate on the surface of the band-shaped metal plate, a predetermined portion of the metal plate is removed by a extracting means. After forming the extraction part whose extraction surface has an inclined shape at the position, the soluble metal is poured into the extraction part by pouring the soluble metal from the side of the extraction area where the extraction area is large, and then the predetermined fixed electrode width and And a step of manufacturing a fixed electrode by cutting the fixed electrode.

Further, according to the method of manufacturing a thermal protector of the present invention, the soluble metal is removed to the extraction section by running the upper surface of a rotating roll provided in the molten metal tank on the metal surface having a larger extraction area. Has a pouring process.

[0008]

According to the thermal protector of the present invention, the contact area of the electrode plate with the soluble metal can be increased in the plurality of electrode plates fixed through the soluble metal, so that the thermal protector becomes a fixed electrode. A plurality of electrode plates can be firmly fixed to each other.

In the method of manufacturing a thermal protector according to the present invention, with such a configuration, the soluble metal flows smoothly between the plurality of electrode plates serving as fixed electrodes, that is, into the extraction portion, and the extraction portion is uniformly filled with the soluble metal. be able to.

Further, according to the method of manufacturing a thermal protector of the present invention, it is possible to easily flow the soluble metal into the extracting portion by such a configuration.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A thermal protector according to an embodiment of the present invention will be described below.

[0012] Thermal protector according to an embodiment of the present invention shown in Figure 1, have a fixed contact 2 to the end and the fixed contact
Fixed electrode 1 in which only the end opposite to point 2 is fixed
And a movable electrode 4 having a movable contact 3 at an end, deformed by heating and coming into contact with and separating from the fixed electrode 1. The fixed electrode 1 has electrode plates 5 and 6 fixed to each other via a soluble metal 7 in the longitudinal direction. The fixed electrode support plate 8 and the movable electrode support plate 9 are fixed by a resin block 10 and a filler 11, respectively. The fixed electrode support plate 8 and the movable electrode support plate 9 are electrically connected to the outside by an external lead wire 12. Connected. In addition, 13 shows a case.

The fixed electrode 1 has a plurality of electrode plates 5 and 6 fixed to each other in the longitudinal direction via a soluble metal 7, and a boundary surface between the electrode plates 5 and 6 fixed by the soluble metal 7. Has an inclined shape.

With such a configuration, even if an excessive current flows when the switch contacts are fused together, the excessive current melts the soluble metal between the electrode plates of the fixed electrode, and the fixed electrode is divided. Therefore, the current can be cut off. In addition, since the contact area between the plurality of electrode plates serving as fixed electrodes and the soluble metal can be increased, the mutual fixation of the plurality of electrode plates can be strengthened, and the strength of the fixed electrode with respect to the inversion return movement can be reduced. Can be enhanced.

Next, a method of manufacturing a thermal protector according to an embodiment of the present invention will be described.

First, as shown in FIG.
As shown in FIG. 3, a fixed contact material 1 which becomes a fixed contact 2 made of Ag having a thickness of 150 μm and a width of 2 mm on a surface of a band-shaped metal plate 14 made of a Cu-Ni-based alloy having a width of 15 mm as shown in FIG.
5 is formed in the length direction of the metal plate 14 by a normal top-lay metal forming method, and then, as shown in FIG. 4, a metal sheet 14 having a width of 700 μm and a length of 7 cm A punched portion 16 was formed by punching out a rectangle so that the extraction surface had an inclined shape.
The portions 19 that are not punched at equal intervals are formed so that the strip-shaped metal plate 14 is bent so that the shape of the extraction portion 16 is not deformed. In addition, FIG.
FIG. 5 is a sectional view of the metal plate 14 taken along a broken line AB shown in FIG. 4.
The arrow C indicates the direction in which the soluble metal 7 is poured. Then, after forming the extraction portion 16 in the metal plate 14, FIG.
As shown in FIG. 2, the surface of the extraction portion 16 having a large extraction area is brought into contact with the rotating roll 17 installed in the molten metal tank 18 containing the soluble metal 7 and the upper portion of the roll 17 is run. The soluble metal 7 is poured from the side of the surface 16 having a large extraction area, that is, the direction indicated by the arrow C shown in FIG. 5, and then cut into a predetermined fixed electrode width, for example, 5 mm in width as shown in FIG. Thus, the fixed electrode 1 is manufactured. As the soluble metal 7, solder (Sn60 / Pb40) melted at 220 ° C. was used.

With such a configuration, the soluble metal 7 can be continuously and uniformly poured into the extraction portion 16 with good yield. Therefore, even if the switch contacts are fused, the above-mentioned fixed electrode of the thermal protector of the present invention having a function of interrupting an excessive current can be continuously and stably produced.

The fixed electrode 1 thus manufactured was fixed to the fixed electrode support plate 8 to which the external lead wire 12 was connected by welding. On the other hand, the movable electrode 4 in which the movable contact 3 was fixed to the movable electrode 4 as a thermally responsive element by welding was fixed to the movable electrode support plate 9 to which the external lead wire 12 was connected by welding. The two support plates 8 and 9 were fixed with a resin block 10 and a filler 11 according to a usual process, and a thermal protector according to one embodiment of the present invention was manufactured as shown in FIG.

Next, in the above-described thermal protector of the present embodiment (product of the present invention) and the above-described thermal protector of the present invention, as shown in FIG. A comparison was made with a thermal protector (comparative product) formed to be perpendicular to the thermal protector.

In the product of the present invention and the comparative product, after performing the specified number of reversing and returning movements 5000 times under the conditions of the maximum rated voltage and current, the fixed contact and the movable contact are forcibly welded, and the maximum current value is reduced. Five times was applied.

As a result, for each of the 50 samples, the soluble metal 7 is blown off as shown in FIG. 8 to open the circuit. Confirmed that it has a blocking function.

Next, after measuring the inversion temperature and the recovery temperature of each of 100 pieces of the present invention and the comparative article, each sample was left under high temperature and high humidity (60 ° C., 95% RH) for 24 hours. After a rated voltage and a current were applied to perform 10,000 inversion and return movements, which is twice the specified number of times, the inversion temperature and the recovery temperature were measured again.

As a result, eight comparative products in which the inversion temperature or the return temperature showed a deviation of 10% or more from each initial value were confirmed. On the other hand, in the product of the present invention, the inversion temperature or the return temperature has a temperature deviation of less than 5% with respect to each initial value, and it has been confirmed that the fluctuation of the temperature characteristic is extremely small. The reason for this is that, as shown in FIG. 9, in the comparative product, since the soluble metal cannot completely enter the extracted portion, it becomes easy to bend from the soluble metal portion of the fixed electrode due to the long-time inversion return movement, and the contact portion from the initial position. It is considered that the result of the considerable deviation affected the accuracy of the inversion temperature or the return temperature.

In the case of the comparative product shown in FIG. 9, since the extraction portion is formed perpendicular to the length direction of the fixed electrode, it is difficult for the extraction portion 16 to flow into the entire extraction portion 16, and the space between the electrode plates of the fixed electrode plate is maintained even after cooling. It is difficult to make the soluble metal 7 exist uniformly. On the other hand, in the case of the product of the present invention shown in FIG. 5, since the extraction surface is inclined and the soluble metal 7 is poured from the one having the larger extraction area, the pouring operation can be performed smoothly, and Is uniformly filled with the soluble metal 7.

Further, the product of the present invention has a higher mutual fixing strength of the electrode plates of the fixed electrode than the comparative product, so that the soluble metal 7
When the band-shaped metal plate 14 into which the metal is poured is cut into a desired width by a press, the occurrence rate of cutting failures in which the metal plate 14 and the soluble metal 7 are separated can be reduced.

In this embodiment, one of the extraction surfaces has an inclined shape. However, as shown in FIG. 10, a part of the extraction surface is provided, and as shown in FIG. As long as a part of the extraction surface or, as shown in FIG. 12, an inclined shape is formed on the extraction surface of one of the electrode plates, the same effect as described above can be obtained in such a case.

In this embodiment, the shape of the extraction portion 16 is a straight line. However, FIGS.
As shown in the rectangle, curve and saw blade shape, respectively
Alternatively, a shape combining these (not shown),
The soluble metal 7 may be poured into the extraction portion 16.

In this embodiment, a pressing method is used as the extracting means. However, a metal plate may be extracted by a laser beam method, an electric discharge machining method, or the like, and an inclined surface may be provided in an extracted portion formed thereby. The effect of can be obtained.

[0029]

As described above, the thermal protector of the present invention can continue to have a function of interrupting an excessive current even when the switch contacts are fused to each other to close the circuit. Further, even after a long-time reversion-returning motion, the fixed electrode is not deformed, and the reversion temperature or the reversion temperature hardly changes from the initial characteristic value, so that the reliability can be extremely improved.

Further, according to the method of manufacturing a thermal protector of the present invention, a soluble metal can be smoothly poured between a plurality of electrode plates serving as fixed electrodes, that is, into a withdrawn portion.
A soluble metal can be uniformly filled in the extraction part.

Further, according to the method of manufacturing a thermal protector of the present invention, it is possible to easily flow a soluble metal into a extracting portion.

[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 diagram for explaining a method of manufacturing a thermal protector according to one embodiment of the present invention.

FIG. 3 is also an explanatory view

FIG. 4 is an explanatory view of the same.

FIG. 5 is a sectional view of the same fixed electrode.

FIG. 6 is also an explanatory view

FIG. 7 is also an explanatory view

FIG. 8 is a diagram showing an internal structure of the thermal protector of the present invention in a state where a soluble metal is molten.

FIG. 9 is a diagram showing a fixed electrode of a comparative thermal protector.

FIG. 10 is a diagram showing another shape of the fixed electrode of the thermal protector according to one embodiment of the present invention.

FIG. 11 is a view showing another shape of the fixed electrode.

FIG. 12 is a view showing another shape of the fixed electrode.

FIG. 13 is a view showing another shape of the fixed electrode.

FIG. 14 is a view showing another shape of the fixed electrode.

FIG. 15 is a view showing another shape of the fixed electrode.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Fixed electrode 2 Fixed contact 3 Movable contact 4 Movable electrode 5, 6 Electrode plate 7 Soluble metal 16 Extraction part 17 Roll

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-5-47278 (JP, A) JP-A-3-102728 (JP, A) Fully open 61-190646 (JP, U) Really open 1974 51473 (JP, U) Actually open 58-338 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01H 37/00-37/56 H01H 11/00-11/06 H01H 85/00

Claims (3)

(57) [Claims] [Claim 1] have a fixed contact to the end portion, and said stationary contact
A fixed electrode in which only the end opposite to the point is fixed,
In a thermal protector having a movable contact at an end, and a movable electrode that is deformed by heating and comes into contact with and separates from the fixed electrode, the fixed electrode has a plurality of electrode plates in the length direction via a soluble metal portion. A thermal protector, wherein a boundary surface between the electrode plates fixed to each other and fixed to the soluble metal has an inclined shape. 2. A strip-shaped fixed contact material is formed on a strip-shaped metal plate surface in the longitudinal direction of the metal plate, and then the stripping surface is inclined at a predetermined position on the metal plate by a stripping means. After forming the portion, the soluble metal is poured from the side of the extraction portion having the large extraction area, the extraction portion is filled with the soluble metal, and thereafter, the fixed electrode is manufactured by cutting to a predetermined fixed electrode width. A method for manufacturing a thermal protector, comprising: 3. The method according to claim 2, wherein the soluble metal is poured into the extraction section by running the upper surface of a rotating roll provided in the molten metal tank on the metal surface on the side where the extraction area is large. Manufacturing method of thermal protector.