JP2003036775A - Thin temperature fuse - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem that it is difficult to reduce the radius of a cylindrical insulating tube, or to form the space in which an insulating film is sealed, etc., related to a circular temperature fuse or an insulating film thermocompression type temperature fuse if the thickness of the temperature fuse in which a lead conductor is connected to a soluble alloy piece is reduced. SOLUTION: The temperature fuse comprises a pair of lead conductors, an insulating material which fixes both lead conductors, a soluble alloy piece which connects the lead conductors together, a flux which makes them globular, and a cap to keep them air-tight. The min body case is bisected into an integral mold case containing the lead conductor part and the cap part to seal them air-tight. The integral mold case containing the lead conductor is provided with an opening only on one side. The lead conductor contacts the bottom part of the resin mold case.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermal fuse formed by joining lead conductors with a fusible metal piece, a so-called alloy type thermal fuse, and to a technique for providing a compact thermal fuse having a low resistance and a thin profile. Is.

[0002]

2. Description of the Related Art A thermal fuse has a small and robust structure having a function of detecting an abnormal temperature and a circuit breaking function.
Detects thermal abnormalities in household or industrial electric equipment and immediately cuts off the circuit to prevent equipment damage or fire. There are two types of heat-sensitive elements, one of which uses a temperature-sensitive pellet, that is, an organic substance, and the other of which uses a low melting point alloy, that is, a fusible alloy piece. Generally, the operating temperature range is about 70 to 240 ° C for the temperature sensitive pellets and about 60 to 190 ° C for the low melting point alloy, that is, the fusible alloy pieces, and the rated current is 0.5 to 15A. It corresponds to a wide range of currents.

The characteristics of the thermal fuse are that it is small and has excellent temperature sensitivity to ambient temperature, that it has an airtight structure in order to have high accuracy of operation with little change in characteristics over time. Then, it is possible to ensure high safety because it does not recover even if the temperature drops, and it is possible to optimize its application by selecting several kinds of thermal fuses according to the application. In particular,
In recent years, high safety has been demanded for so-called household electric appliances and industrial electronic devices, and thermal fuses of this kind have been widely used in households and industries.

The above-mentioned thermal fuse is specifically an electric kotatsu or an electric stove, an electric carpet, an iron or a trouser press, a hair dryer, an air conditioner or a fan, a gas bath or a gas water heater, a pencil sharpener, a sewing machine, a liquid crystal television or a game. Bowl, color TV and stereo, video, refrigerator, electric rice cooker, microwave oven, fluorescent lamp, desk lamp,
It is used in various products such as transformers, power supplies, inverters, chargers, rechargeable batteries, battery packs, copiers and printers. It is also used as an industrial machine in various types of manufacturing equipment and processing equipment.

As described above, there are basically two types of temperature fuses depending on the type of the temperature sensitive element, that is, the temperature sensitive pellet type and the fusible alloy type, but the temperature fuse of the present invention is particularly applicable. Thermal fuse made by joining lead conductor to molten alloy piece,
Since the present invention relates to a so-called alloy type thermal fuse, the conventional technique will be described below focusing on this point. As this type of thermal fuse, for example, a cylindrical fuse as disclosed in Japanese Utility Model Laid-Open No. 57-141346 is used (FIG. 8). In this case, a linear fusible alloy piece 24 is welded to a pair of linearly opposed lead conductors 21, and a flux 25 is applied to the fusible alloy piece 24 to obtain a fusible alloy structure. Insulation cylinder 23 made of ceramics or the like
Into the insulating tube 23 and the lead conductor 21.
It has a structure in which the space between and is sealed by a sealing material 22.

In recent years, thin-type thermal fuses having a thickness of less than 1 mm have been used due to the thinning of electronic equipment. For example, JP-A-02-291624
Film laminations such as those disclosed in US Pat. FIG. 9 shows a partially cutaway sectional view of a conventional most common thin thermal fuse, and FIG. 10 shows a plan view thereof. The temperature fuses shown in FIGS. 9 and 10 are
The insulating plate 312, which is a thermoplastic resin, has one surface 3a which is the lower surface and the other surface 3b which is the tip portion 3 of the lead conductor 32.
Set 21 to be flush with each other,
Further, a fusible alloy 33 is bridged and welded between the tip portions 321 and a flux 34 is coated, and in addition, a sheet-like insulating plate 35 which is another thermoplastic resin is added.
Is bonded by thermocompression at the adhesion margin 351.

[0007]

However, in the case of a round type thermal fuse, a cylindrical member is used as the material thereof, and it is difficult to reduce the radius of the column and further reduce the thickness. Further, in the case of film type lamination, it is necessary to form a space for sealing the fusible alloy pieces in advance. In this type of internal space forming method, it is indispensable to form the corners round, and it is inevitable to reduce the internal space by downsizing. For this reason, the cross-sectional area of the fusible alloy piece becomes small and an increase in the resistance value cannot be avoided.

An object of the present invention is to provide a thin type thermal fuse which is small in size and thin in thickness while suppressing an increase in resistance value, and has excellent thermal response.

[Means for Solving the Problems]

In order to achieve the above object, in the thin type thermal fuse of the present invention, a lead conductor having an opening only on the cap seal surface and a resin-integrated case are molded in advance,
A fusible alloy piece is joined to this and flux is applied to seal the resin-integrated case and the cap. Thus, the thin thermal fuse is characterized in that the lead conductor and the molding resin are brought into close contact with each other in the case by integrally molding the lead conductor and the case having an opening on only one side.

That is, the thermal fuse of the present invention overcomes the problem of thinning of the round type by making the case, the lead conductor and the fusible alloy piece into a plate shape, and the film type has a problem. Regarding the reduction of the internal space area due to the presence of the rounded corners when forming the space for encapsulating the fusible alloy pieces, use a square cavity (internal space) and preferably a square low melting point solder. In addition, by embedding or closely adhering the lead conductor to the resin molded product in the lead resin integrated molding case, improvement in heat sensitivity can be expected.

BEST MODE FOR CARRYING OUT THE INVENTION Next, embodiments of the present invention will be described in detail.

The various configurations of the present invention and the effects thereof will be described below. FIG. 1 is a vertical cross-sectional view of a temperature fuse with a cap, showing an embodiment of a lead conductor and a resin-integrated thin thermal fuse according to claim 1 of the present invention. FIG. 2 shows a plan view of the temperature fuse with the cap 2 removed. This lead conductor-resin integrated thin type thermal fuse is constructed by incorporating a pair of strip-shaped lead conductors 1, 1 and the above-mentioned lead conductor on the bottom plate of the resin case 3 by integrally molding the resin and the lead conductor, and forming the bottom surface of the resin case opening. The thermal fuse is characterized in that the two lead conductors fixed on the top are joined by a fusible alloy piece 4, a flux 5 is applied in the opening of the case, and the opening is cap-sealed.

The invention according to claim 2 of the present invention is a thin thermal fuse characterized in that when the lead conductors 1, 1 are integrally molded with the lead conductors, a part of the lead conductor in the case opening is buried. is there. As described above, by burying the lead conductors 1 and 1 not only in the outer wall portion but also in the cavity in the resin case, it is possible to prevent bending and floating of the tips of the lead conductors 1 and 1 in advance. A good fusible alloy piece 4 can be attached. For this reason, the lead conductor to be embedded is not required to have both sides in the resin as long as the above-mentioned object is achieved. Further, this allows the resin case material and the lead conductor to be brought into close contact with each other, which is advantageous for downsizing and thinning. Furthermore, since there is no air layer between the resin case and the lead conductor, a thin thermal fuse excellent in thermal response can be realized.

The invention according to claim 3 of the present invention is the above-mentioned thin-type thermal fuse, characterized in that a thermoplastic resin is used for the cap 2 and the resin case 3 which are molded case materials. As described above, by using the thermoplastic resin as the molding case material, not only the time required for resin lead and resin integral molding can be shortened, but also the heat welding method can be adopted at the time of sealing the case and the cap thereafter. It is possible to perform resin sealing without using such as. The following can be used as examples of the thermoplastic resin that can be used in the present invention. Polyethylene terephthalate (hereinafter abbreviated PET) is used for the material of the cap 2 and the resin case 3,
Polyethylene naphthalate (hereinafter abbreviated PEN), polyphenylene sulfide (abbreviated PPS), polycarbonate (hereinafter abbreviated PC), polybutylene terephthalate (hereinafter abbreviated PB)
T), acrylonitrile-butadiene-styrene resin (abbreviated as ABS hereinafter), PAR (polyarylate), PTFE
A single or alloyed thermoplastic resin containing (polytetrafluoroethylene), POM (polyacetal) and LCP (liquid crystal polymer) as main components can be used.
Further, the material used at this time does not necessarily need to be the same as the resin molded case of the lead conductor and the cap, and may be joined by different materials. By selecting the material in this way, it becomes possible to obtain a molded product according to the ambient temperature, humidity and the like. Furthermore, by selecting a transparent thermoplastic resin, it becomes possible to obtain a thermal fuse in which the presence or absence of disconnection can be visually confirmed. For example,
Transparent grades such as PET, PEN and PC can be selected. Further, as a filler, various fillers and various property improving materials such as an antiaging agent and a copper damage inhibitor may be added.

According to a fourth aspect of the present invention, at least the lead conductors 1, 1 are joined to the fusible alloy pieces 4 and the electrode portions 1a, 1a required for spheroidizing,
A thin thermal fuse integrated with a lead conductor and a resin, which is characterized by being partially plated. Details of the present invention will be apparent from each of the embodiments described below. Thus, by plating the soluble alloy joint portion, it becomes possible to improve the solderability and promote spheroidization during operation. Examples of plating species that can be used in the present invention include the following. Sn, Pb, In, Bi, Zn, Ag mainly composed of solder,
By combining one or more of Ni and Cu, it is possible to select a combination in consideration of the melting point and wettability of various fusible alloy pieces. As described above, by providing the plating species containing solder as the main component, the solder wettability can be improved and the spheroidization of the soluble alloy can be assisted. You can

The invention according to claim 5 of the present invention is the invention according to claim 1.
In the integrated molding including the lead conductor described above, the case is a lead-conductor-integrated thin-type thermal fuse characterized in that the opening area increases as it goes to the opening. By thus increasing the opening area toward the opening, it becomes easier to position the fusible alloy piece 4 at the time of feeding, and there is an effect of improving workability. In addition, since the internal space can be widened by taking a large opening area, it becomes possible to assemble a fusible alloy piece with a large cross-sectional area.
As a result, it is possible to provide a low temperature thin fuse.

The invention according to claim 6 of the present invention is the invention according to claim 1.
A lead resin-integrated thin-type thermal fuse, characterized in that, in the integrally molded case including the lead conductors (1), (1) described above, a protrusion is provided in a part of an opening of the case. By providing the protrusions in a part of the opening portion in this manner, the fusible alloy piece 4 can be easily fixed, and the positioning accuracy during welding of the fusible alloy piece can be improved. Therefore, stable welding can be performed. Here, since the present invention is used for a thermal fuse, it is preferable that the position of the protrusion is between the electrodes, but the protrusion may be formed anywhere within the range permitted by the present purpose.

According to a seventh aspect of the present invention, the integrally molded case 3 or the cap 2 including the lead conductors 1 and 1 is provided.
Is a resin-integrated thin-type thermal fuse in which a rib is formed on either one of the sealing surfaces. By providing the ribs on the sealing surface in this way, the heat generation time in ultrasonic welding can be shortened, so that it is possible to provide a thermal fuse that can reduce the influence on the thermal fuse.

The invention according to claim 8 of the present invention is a thin thermal fuse with integrated lead conductor according to claim 1, characterized in that a resin is applied from the outside to the joint between the lead conductors 1, 1 and the resin. is there. Depending on the usage environment, further air tightness may be required. By applying the resin after molding in this way, it is possible to prevent a decrease in airtightness due to insufficient adhesion due to interfacial peeling or the like due to a difference in thermal expansion coefficient generated during injection molding. Further, it is possible to prevent / reduce the occurrence of cracks due to stress applied to the leads. Resins that can be used include epoxy resins and UV
Resin or the like can be used.

The invention according to claim 9 of the present invention is the lead-conductor integrated thin-type thermal fuse according to claim 1, characterized in that a hole a is formed in a part of the lead conductors 1, 1.
By thus forming the holes a on the lead conductors 1 and 1 at predetermined positions, the following effects can be expected. First, when it is provided in the frame of the resin molding case 3,
This has the effect of fixing the resin molding case 3 and the lead conductors 1, 1. Moreover, as shown in FIG.
By providing it outside, the stress applied to the lead conductors 1, 1 can be relieved. Next, if this hole a is formed so as to cover a part of the case, a thin thermal fuse having the above-mentioned two effects is obtained.

Embodiments of the present invention will be described below with reference to the drawings.

First Embodiment FIG. 1 shows a first embodiment of the present invention.
It is a side view longitudinal cross-sectional view of a temperature fuse with a cap. FIG. 2 shows the first embodiment and is a plan view of the temperature fuse with the cap removed. Below, the example of a member of 1st Embodiment is shown. 1: Lead conductor 2: Cap 3: Resin molding case 4: Soluble alloy piece 5: Flux 6: Plating layer 7: Adhesive 1a: Electrode part In FIGS. 1 and 2, 1 indicates a lead conductor. Although phosphor bronze is used for the lead wire in the first embodiment, other pure materials or alloys such as copper wire, iron wire, and brass can be used, and the surface can be plated.
The lead conductor may have a flat plate shape or a round wire shape, and may be deformed or pressed. The contact surface between the lead conductor and the resin may be provided with irregularities or through holes by a physical / chemical method for improving the adhesion strength. 2 indicates a cap. An example in which alumina ceramic is used as the cap is shown. A resin molded case 3 is integrally molded with the lead conductor 1.
A thermosetting epoxy resin can be selected as the resin used here. Reference numeral 4 is a fusible alloy piece, and various temperature fuses can be made by blending easily meltable metals. Here, as an example, SnPb (183 ° C. product: 63 wt%, balance) having a melting point at 183 ° C. is used as a soluble alloy piece. Since the shape is a thin product, it is preferable to use an ellipse to a rectangular piece, but the use of a round wire fusible alloy piece does not affect the gist of the present invention. Further, since the lead conductor 1 and the resin molded product 3 are in close contact with each other, it is stable even when thermocompression bonding or the like is used as a welding method such as a positional deviation or a pressure from above when welding the fusible alloy piece 4. Welding becomes possible. Further, as the product, the resin molded product 3 and the lead conductor 1 are in close contact with each other without an air layer therebetween, and thus the thermal fuse has a good thermal response. Reference numeral 5 is a flux, and a material composed of rosin, wax, activator and the like can be selected. 6 is a plating formed on the lead conductor, and tin plating is used here. The type and place of plating can be arbitrarily selected depending on the welding method, cost, place of use, molding resin material used, and the like. In the first embodiment, a solder plating layer is provided on the entire surface because it is a soldered product, but in the case of joining with a counterpart member by resistance welding, not only the material of the lead conductor is selected, but also the plating position is partial plating or the like. be able to. By using SnCu as the plating species, it is possible to prevent remelting of the plating even when using a thermosetting epoxy resin that requires a high mold temperature during resin molding. 7
Is an adhesive, and in the first embodiment, the cap 2 and the resin molded case 3 can be joined by an adhesive. Next, the manufacturing method of the first embodiment will be described. A plating layer 6 is formed by plating the lead conductors 1, 1. The lead conductors 1, 1 are punched into a strip shape by pressing. The lead conductors 1, 1 are subjected to an injection molding machine to make an integrally molded product of the lead conductors and the thermosetting resin. The soluble alloy piece 4 is placed on the plated lead conductor and joined to the plated metal. Flux is applied on the fusible alloy piece 4 in the opening on the upper surface. An adhesive is applied to the four sides of the alumina ceramic cap 2, the adhesive is applied to the openings of the lead conductor resin molded product, and after curing, the frame is cut to obtain the element of the first embodiment. In addition, Example 1 is shown below.

Example 1 Lead conductor 1: Phosphor bronze Cap 2: Alumina ceramic Resin molding case 3: thermosetting epoxy resin Soluble alloy 4: SnPb (183 ° C product, 63 wt%, balance) Flux 5: Rosin, wax, activator, etc. Plating 6: Tin-copper plating Adhesive 7: UV resin

[0021]

Second Embodiment FIG. 3 shows a second embodiment of the present invention,
It is a side view longitudinal cross-sectional view of a temperature fuse with a cap. FIG. 4 shows the second embodiment and is a plan view of the temperature fuse before the cap seal. Below, the example of a member of 2nd Embodiment is shown. 1: Lead conductor 2: Cap 3: Resin molding case 4: Soluble alloy piece 5: Flux 6: Plating 8: Rib a: Hole 1 in FIGS. 3 and 4 is a lead conductor, and a nickel material is used here. ing. Further, in order to prevent the bendability of the lead conductor and the resin molded product from being cracked, the bent portion of the lead conductor may be processed to have a hole or a narrow portion. 2 indicates a cap. As the material that can be used for this, LCP was used as the thermoplastic resin this time, but various materials can be used as long as the material is a thermoplastic resin. Further, the cap here is not limited to the frame shape, and may be a flat plate-like one as in the second embodiment or a rib may be formed in the seal portion. 3 is a resin molding case which is obtained by integral molding with the lead conductor. As the material that can be used here, various thermoplastic resins other than LCP can be used. The thermoplastic resin may be alloyed as a characteristic improvement, and various characteristics such as heat-welding property and heat resistance can be improved by alloying. 4 is a fusible alloy piece. 5 is a flux. 6 is tin plating on the lead conductor. In addition, since the plating place is considered to be joined by resistance welding, it is performed only on the fusible alloy piece joining portion and its periphery. However, tin plating may be applied to the entire surface even if it is a resistance welding product due to cost problems. The plating area will be further described. The plating area differs depending on the combination of the volume V of the soluble alloy piece, the electrode area S, and the cavity height h. Further, here, the electrode area S is the area on one electrode side indicated by 6'in FIG. There is a margin in the product height and the cavity height h
If h is high, the electrode area may be small, but conversely, in the present invention where thinness is required, it is preferable that h is small as a whole. In this case, if V is the same, it becomes necessary to increase the electrode area S. The following relational expression (1) can be derived by mathematically expressing the above relation. S × h ≧ V ··· (1) In addition, when manufacturing a low resistance thin temperature fuse, V
In this case, it can be realized by taking an electrode area satisfying the relational expression S ≧ V / h. Reference numeral 8 denotes a rib, which can be formed on the sealing surface on the cap side or the molding case side. By providing the ribs on the sealing surface of the thermoplastic resin, airtight sealing can be performed by ultrasonic welding as a welding method without using an adhesive. This also leads to a reduction in material costs and man-hours.

Next, the manufacturing method of the second embodiment will be described. Plating layer 6 by partial plating of lead conductors 1, 1
To form. The lead conductors 1 and 1 are stamped into a strip shape. The lead conductors 1, 1 are subjected to an injection molding machine to make an integrally molded product of the lead conductors 1, 1 and the thermoplastic resin. The fusible alloy piece is placed on the plated lead conductors 1, 1 and joined to the plated metal. Flux is applied on the fusible alloy piece 4 in the opening on the upper surface. The thermoplastic resin cap 2 is aligned with the lead conductor resin molding case opening K and heat-bonded, and finally the frame is cut to obtain the element according to the second embodiment. In addition, Example 2 is shown below.

Example 2 Lead conductor 1: Nickel plate cap 2: LCP (liquid crystal polymer) Resin molding case 3: LCP (liquid crystal polymer) Soluble alloy piece 4: SnPbIn (130 ° C .; 49 wt%, 17)
wt%, remaining) Flux 5: Rosin, wax, surfactant plating, etc. 6: Tin plating rib 8: LCP (liquid crystal polymer)

[0023]

[Third Embodiment] FIG. 5 shows a third embodiment and is a vertical cross-sectional view of a temperature fuse with a cap. Figure 6
[FIG. 6] is a plan view of the temperature fuse before the cap seal according to the third embodiment. 1: Lead conductor 2: Cap 3: Resin molding case 4: Soluble alloy piece 5: Flux 6: Plating 8: Rib 9: Adhesive a: Hole b: Protrusion In the third embodiment, the surface is roughened and the resin molding case is further formed. The resin molded case 3 and the nickel lead conductor 1 are formed by using the lead conductor 1 of the nickel plate having the hole a formed in the space 3.
Improves adhesion strength with. As a combination of the cap 2 and the resin molded case 3, a transparent PET grade is used for the cap 2 and PBT is used for the resin molded case 3. In this way, by using PBT having high moldability in the molding part and using PET which is easily available as a transparent sheet-molded product in the cap part, it is possible to make a combination utilizing the respective characteristics. In addition, the lead conductor 1 of the resin molded case 3
The protrusion b is provided between them, but this has the effect of increasing the positioning accuracy when the soluble alloy piece is supplied, and can stabilize the welding state. Further, the position of the lead conductor 1 does not necessarily have to come to the upper surface of the bottom portion of the opening of the resin molded case 3 as in the first and second embodiments.
You may bury it like this. The lead conductor 1 of the present invention is
In this manner, the state in which the resin molded case 3 and the resin molded case 3 are in close contact with each other without the air layer interposed therebetween indicates that a part of the lead conductor 1 is in the resin not only in the plane but also in the thickness direction. It is. In this way, the lead conductor 1 is formed into the resin molded case 3
By being embedded in the fusible alloy piece 4, not only the heat transferred from the lead conductor 1 but also the heat from the resin molded case 3 can be directly transferred, so that the fusible alloy piece 4 is excellent in thermal response. Also,
Since the internal space can be widened, it is advantageous for downsizing and thinning. Regarding the crack of the resin molded product caused by bending of the lead conductor 1 or the like, the adhesive 9 is used here in addition to the process of drilling the lead conductor or narrowing a part of the lead conductor as described in the second embodiment. It may be prevented by applying it to the connecting portion between the resin molded case 3 and the lead conductor 1.

Next, the manufacturing method of the third embodiment will be described. A plating layer 6 is formed by plating the lead conductors 1, 1. The lead conductors 1, 1 are punched into a strip shape by pressing. The lead conductors 1, 1 are subjected to an injection molding machine to make an integrally molded product of the lead conductors and the resin case 3. The fusible alloy piece 4 is placed on the plated lead conductors 1, 1 and joined to the plated metal. Fusible alloy piece 4 at the top opening
Apply flux 5 on top. The resin molding case 3 and the cap 2 are heat-sealed by ultrasonic welding. The molded product according to the third embodiment can be obtained by applying the adhesive 9 on the lead conductors 1 and 1 and curing it. In addition, Example 3
Is shown below.

[Embodiment 3] Lead conductor 1: Nickel plate cap 2: PET (polyethylene terephthalate) Resin molding case 3: PBT (polybutylene terephthalate)
G) Soluble alloy piece 4: SnPbBi (98 ° C; 16wt%, 32w
Flux 5: Rosin, wax, activator plating 6: PbSn plating rib 8: PET (polyethylene terephthalate) Adhesive 9: UV resin hole a: Round hole protrusion b: Step shape

[0025]

As described above, according to the present invention, since the temperature fuse element is constructed as described above, the size and thickness can be easily reduced and the top and bottom are flat and the thermal response is excellent as compared with the conventional film molded product. . A conceptual diagram comparing the internal spaces is shown below in FIG. In this way, comparing the internal cross-sectional areas, it can be clearly seen that the sizes increase in the order of cylindrical type <film type <mold type. Therefore, in the case where a thermal fuse having the same resistance value is produced, the lightest, thinnest, shortest size can be achieved as compared with the conventional one.

[Brief description of drawings]

FIG. 1 shows a first embodiment of the present invention, and is a vertical cross-sectional view of a temperature fuse with a cap, as viewed from the side.

FIG. 2 is a plan view of the temperature fuse showing the first embodiment of the present invention and having a cap removed.

FIG. 3 shows a second embodiment of the present invention, and is a vertical cross-sectional view of a temperature fuse with a cap attached, as viewed from the side.

FIG. 4 shows a second embodiment of the present invention and is a plan view of a temperature fuse before a cap seal.

FIG. 5 shows a third embodiment of the present invention, and is a vertical cross-sectional view of a temperature fuse with a cap, as viewed from the side.

FIG. 6 shows a third embodiment of the present invention and is a plan view of a temperature fuse before a cap seal.

FIG. 7 is a conceptual diagram for explaining the function and effect of the present invention.

FIG. 8 is a vertical cross-sectional view showing a conventional temperature fuse.

FIG. 9 is a vertical cross-sectional view as seen from a side view showing a conventional temperature fuse.

FIG. 10 is a partially cutaway plan view showing a conventional temperature fuse.

[Explanation of symbols]

1 lead conductor 1a Electrode part 2 cap 3 Resin molding case 4 Soluble alloy 5 flux 6 plating layer 7 adhesive 8 ribs 9 Adhesive a hole b protrusion

Continued front page    (72) Inventor Masayasu Nishikawa             3-1 Nichiden, Mizuguchi-cho, Koga-gun, Shiga Prefecture             − See Shot Components Co., Ltd.             In-house (72) Inventor Ryosuke Miura             3-1 Nichiden, Mizuguchi-cho, Koga-gun, Shiga Prefecture             − See Shot Components Co., Ltd.             In-house (72) Inventor Katsuyuki Murata             3-1 Nichiden, Mizuguchi-cho, Koga-gun, Shiga Prefecture             − See Shot Components Co., Ltd.             In-house (72) Inventor Yoshiharu Komori             3-1 Nichiden, Mizuguchi-cho, Koga-gun, Shiga Prefecture             − See Shot Components Co., Ltd.             In-house F-term (reference) 5G502 AA02 BA02 BB05 BC02 JJ01

Claims (9)

[Claims] 1. A thermal fuse comprising a pair of lead conductors, an insulating material for fixing the lead conductors, a fusible alloy piece for connecting the lead conductors, a flux for spheroidizing the fusible alloy piece, and a cap for airtightly holding the flux. The main body case part consists of an integrally molded case that includes the lead conductor part and a cap part that hermetically seals it, and the integrally molded case that contains the lead conductor has a structure in which the opening is provided on only one side. A thin thermal fuse characterized in that the lead conductor is in contact with the bottom of the resin molded case. 2. The thin thermal fuse according to claim 1, wherein the lead conductor width in the case opening is wider than a part of the case bottom opening. 3. A thin thermal fuse according to claim 1, wherein a thermoplastic resin is used as the integrally molded case material. 4. A thin thermal fuse according to claim 1, wherein the lead conductor is plated at least at a fusible alloy piece joint portion and its periphery. 5. A thin-type thermal fuse according to claim 1, wherein the integrally molded case including the lead conductor portion has an opening area increasing toward the upper surface of the opening. 6. The thin thermal fuse according to claim 1, wherein the integrally molded case including the lead conductor portion is provided with a protrusion in a part of the opening. 7. A thin thermal fuse according to claim 1, wherein a rib is formed on a sealing surface of either the integrally molded case including the lead conductor portion or the cap. 8. A thin thermal fuse according to claim 1, wherein a resin is applied from the outside to the joint between the lead conductor and the resin. 9. A thin temperature fuse according to claim 1, wherein a hole is formed in a part of the lead conductor.