JPH05174680A - Thermal fuse and manufacture of thermal fuse - Google Patents

Abstract

PURPOSE:To carry out butt soldering without differentiating the core, and to use an enlarged part as a plug to inhibit inflow of a bonding agent by enlarging a front end part of a lead by press and compression to form a recessed part, and by making the recessed part receive the front end of a temperature sensitive element consisting of a special alloy wire. CONSTITUTION:When a temperature sensitive element 2 consisting of a special alloy is connected to the intermediate part between a pair of leads 1, and is sealed in an external case 4 to form a thermal fuse, the front end of the lead 1 makes an enlarged part 30 provided with a recessed part 3 on the center part, and the element 2 is inserted into the enlarged part and is welded. A bonding agent 5 of epoxy resin is used to close and seal the both ends of the case 4, and the inside of the case 4 is made airtight. Since pieces of the element melted and broken responding to a set temperature are converged into the enlarged part instantaneously and are formed into spheres, fuse breaking velocity is expedited, and the breaking of an electric circuit connected to the fuse is ensured.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermal fuse and a method for manufacturing the thermal fuse. What is a thermal fuse?
It is not directly related to the amount of current flowing in the connected electric circuit, and when the ambient temperature rises to a certain temperature, the alloy of special composition (hereinafter referred to as the temperature sensitive element) incorporated in the case is automatically It is the name of an electrical component that has the function of melting itself and breaking the electrical circuit connected to it. In particular, the present invention relates to a cylindrical packaged thermal fuse having a lead wire with a special tip shape, which has a great effect on quality improvement and cost reduction, and a manufacturing method thereof.

[0002]

2. Description of the Related Art Conventional thermal fuses suffer from many structural difficulties due to the structural defects described below, and their countermeasures are difficult. Various developments have been made to maintain the sensitivity and performance of the thermal fuse, but on the contrary, it causes a cost increase and hinders the reduction of manufacturing cost.

[0003]

The conventional thermal fuse has the following structural and manufacturing defects. When making a temperature-sensitive element wire (a temperature-sensitive element wire is made by directly abutting a temperature-sensitive element between two lead wires and soldering each other, which will be referred to as a "temperature-sensitive element wire"), which is the basis of the thermal fuse. , When soldering each lead wire and the temperature sensitive element, the end face comrades were carefully butt-jointed so that the center of the comrades would not be misaligned. As a result, there were many misalignments, which required a large number of tools and jigs as well as advanced technology and skill. Especially when the lead wire or the temperature sensitive element is thin (there are many types of thickness of the lead wire and the temperature sensitive element depending on the current capacity), the wire is weak and the core is liable to be misaligned. Requires advanced technology and skill,
I needed more advanced tools and jigs. When inserting the soldered temperature sensitive element wire into the cylinder (exterior case), advanced tools and jigs are required to align the center of the cylinder (exterior case) with the center of the temperature sensitive element wire. Yes The work required a high level of skill and skill. When the openings at both ends of the tubular body (exterior case) into which the temperature sensitive element wire is inserted are sealed and adhered with an adhesive, there is a difficulty in preventing the inflow of the adhesive. This is because if the adhesive adheres to the temperature-sensitive element, the performance and sensitivity of the thermal fuse will deteriorate, resulting in a defective product and a reduction in yield. The temperature sensitive element soldered between the two lead wires reacts to the set temperature, melts and breaks, and the melted fragments collect on both lead wires, interrupting the electric circuit energized there. However, the solder (the temperature-sensitive element is designed to melt at a predetermined temperature and is a special solder of a specially mixed alloy) has a leakability (when the solder melts, it spreads and spreads). Due to the leakiness of the lead wire), the lead wires end up condensing on the end surface of the lead wire, and the speed of the leaking property and the amount of the collected fragments are proportional to the cross-sectional area of the lead wire. In addition, there is a limit to the amount of fragments that can be collected on the lead wire, which has been a barrier to further improvement in sensitivity and performance of the thermal fuse. Further, the thermal fuse for large current is soldered by directly abutting a single lead wire having a thickness suitable for the current value and the temperature sensitive element. However, it is certain that the reaction of the thermal fuse of the same electric capacity that reacts to the same set temperature is transmitted to the center of one thick temperature sensitive element and melts and fractures, and that several thin temperature sensitive elements melt and fracture. Moreover, it reacts quickly.
It has been considered more difficult to bond a plurality of temperature sensitive elements to a lead wire.

The present invention solves the problems as described above. The tip of the lead wire is compressed and expanded, and the end face is molded into a recess, whereby the temperature is sensed in the recess. The tip of the element can be received and easily abutted and soldered without misalignment, and the enlarged portion of the tip can be fitted into the cylinder (outer case) to facilitate centering, and the enlarged portion can be plugged. It prevents the inflow of adhesive and improves the performance of the thermal fuse, and the large surface of the expanded portion collects molten fragments instantly and in large quantities on both lead wires to form a ball. An object of the present invention is to provide a thermal fuse and a method for manufacturing the thermal fuse, which can improve the sensitivity and can significantly improve the yield. The concave portion at the tip of the lead wire is not limited to one temperature-sensitive element, but can be formed to have a size or a plurality of concave portions into which a plurality of temperature-sensitive elements can be put together. When soldering several thin temperature sensitive elements for large current all together, if a curved recess is used, several thin temperature sensitive elements will not be dispersed and can be collected and soldered in the center of the recess of the lead wire. it can. It should be noted that although some shapes of the tip end portion are disclosed, the shape and size thereof can be appropriately designed or changed.

[0005]

In order to achieve the object of providing a highly sensitive and economical thermal fuse, the present invention has developed the following structure. When the lead wire and the temperature-sensitive element are butted against each other and soldered, the tip of the lead wire is compressed and expanded from the linear direction to prevent misalignment, and a special shape such as a dish Then, the flat end surface is molded into a recess, and the recess is used as a tray to receive the temperature sensitive element. With this configuration, butt soldering can be performed without mutual misalignment of the lead wires. The tip of the lead wire is not necessarily limited to a dish shape, but can be designed in any shape such as a trumpet shape, a star shape, or flattened like a nail head. It suffices if a concave portion is provided. The enlarged portion of the tip portion of the lead wire is designed to have an appropriate size and thickness, and is inserted into both ends of the cylindrical body (exterior case). With this configuration, the cylindrical body (exterior case) and the temperature-sensitive element wire can be easily centered. No special tools or jigs are required, neither advanced technology nor skill is required. In the manufacturing process, when the temperature sensitive element wires are sealed and adhered to the openings at both ends of the cylindrical body (exterior case) with the adhesive, the enlarged portions of the lead wires are arranged so as to function as plugs. With this configuration, the inflow of the adhesive is prevented and the adhesive is not brought into contact with the temperature sensitive element lines, so that the yield can be improved without deteriorating the performance of the thermal fuse. The tip of the lead wire is enlarged. When the thermal fuse actually operates, that is, when the temperature sensitive element soldered between the two lead wires reaches the set temperature of the external temperature, the fragments of the temperature sensitive element that have reacted and melted, It is best to instantly gather and condense on the end faces of both lead wires, and the enlarged part at the tip of the lead wire has a much larger cross-sectional area ratio than the lead wire itself, so the solder leakage property spreads. A thermal fuse with good performance and sensitivity can be manufactured. The lead wire has a concave portion at the tip. Several thin temperature-sensing elements, which have a cross-sectional area equal to that of one thick temperature-sensing element, react faster and reliably melt and break. It is possible to collectively press several thin temperature sensitive elements against the concave portion of the lead wire, and collect several thin temperature sensitive elements in the central portion of the concave portion of the lead wire for soldering without dispersing them. The thickness and the number of thin temperature sensitive elements can be appropriately designed according to their electric capacity,
Also, several can be twisted together.

According to the present invention, in a thermal fuse in which a temperature sensitive element is connected between a pair of lead wires and enclosed in a cylinder,
A thermal fuse is proposed in which the ends of the lead wires facing each other are enlarged portions provided with a concave portion, and a temperature sensitive element is welded to the concave portion. Similarly, in a thermal fuse in which a temperature sensitive element is connected between a pair of lead wires and enclosed in a cylindrical body, the leading end of the lead wire is an enlarged portion having a recessed portion at the center, and the recessed portion has a same or different current capacity. Book temperature sensor,
In other words, a temperature fuse is proposed in which temperature sensitive elements having the same diameter or different diameters are welded.

Further, as a manufacturing method thereof, in a method of manufacturing a thermal fuse in which a single or a plurality of temperature sensitive elements are connected between a pair of lead wires and enclosed in a cylindrical body, the tip end of each lead wire is applied in a straight line direction. A pressure-compressed portion is formed as an enlarged portion, and a concave portion is formed on the end surface of the enlarged portion. The concave portion is made to face in a straight line direction and a temperature-sensitive element of a predetermined length is abutted and welded to form a temperature-sensitive element wire. A method of manufacturing a thermal fuse, characterized in that the enlarged portions are positioned at both ends of a cylindrical body having an inner diameter substantially the same as the portion and sealed with an adhesive.

In the thermal fuse having this structure, the temperature sensitive element is abutted against the concave portion of the end face of the lead wire,
It is possible to regulate the mounting direction and solder at uniform positions. The concave portion serves as a tray for the temperature sensitive element, and the core is prevented from being displaced. Further, if the enlarged portion at the tip of the lead wire is designed to fit into the tubular body (exterior case), the tubular body (exterior case) and the temperature-sensitive element wire can be easily aligned with each other. Furthermore, when the openings at both ends of the tubular body (exterior case) into which the temperature sensitive element wire is inserted are sealed and adhered, the enlarged portion of the lead wire acts as a stopper to prevent the inflow of the adhesive. To do.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a thermal fuse and a method of manufacturing a thermal fuse according to the present invention will be described with reference to the drawings.
In the embodiment shown in FIG. 1, in a thermal fuse in which a temperature sensitive element 2 such as a special alloy wire is connected between a pair of lead wires 1 and enclosed in a cylindrical body (exterior case) 4, the tip of the lead wire 1 is located at the center. The thermal fuse is characterized in that an enlarged portion 30 having a recess 3 is provided and the temperature sensitive element 2 is inserted and welded in the recess 3. Reference numeral 5 in the figure denotes an adhesive such as an epoxy resin, which closes and seals both ends of the tubular body (exterior case) 4. The inner diameter Y of the cylindrical tubular body (exterior case) 4 and the outer diameter of the enlarged portion 30 at the tip of the lead wire 1 are substantially the same, and the shape thereof is formed into a disk shape that fits into the cylindrical space. The lead wire 1 is molded by pressing and compressing one end of the lead wire 1 from the linear direction as shown by an arrow in FIG. 2 (enlarged view) to expand it into a dish shape, and provide a recess 3 in the end face thereof. It is a thing. Further, it is also possible to change the design of the structure in which the enlarged tip portion 30 is molded as a separate component of a disk body having the recesses 3 formed on both sides and the lead wire 1 is bonded to one side. The shape of the enlarged tip portion 30 is shown as a dish, but various shapes such as a trumpet shape, a star shape, and a nail head shape can be designed as in each example of FIG. 3ABCD.

The thickness of the lead wire 1 and the size of the deep plate-shaped or trumpet-shaped enlarged portion 30 should be adjusted according to the current flowing therethrough.
The size and depth of the recess 3 can be appropriately designed according to the thickness of the temperature sensitive element 2. The concave portion 3 may have a curved and dented shape, or a dovetail shape. The recess 3 is
Depending on the case, a plurality of large and small pieces may be formed. If a plurality of concave portions 3 are provided, not only one temperature sensing element 2 but also a plurality of temperature sensing elements 2 having the same or different current capacity, that is, a plurality of temperature sensing elements having the same diameter or different diameters. 2 can also be welded. FIG. 4 is a side view showing a state where several thin temperature sensitive elements 2 are collectively soldered, and FIG. 5 is a side view showing a state where several temperature sensitive elements 2 are twisted together. If the temperature sensitive element 4 is fitted to the concave portion 3 at the tip of the lead wire 1 having such a shape and heated by a soldering iron or the like, it does not require high skill or skill, and does not require special tools or jigs. It is possible to perform soldering by linearly contacting each other without causing misalignment.

FIG. 6 is a process chart showing a method of manufacturing a thermal fuse. As a manufacturing method, in the method of manufacturing a thermal fuse in which a single or a plurality of temperature sensitive elements 2 are connected between a pair of lead wires 1 and enclosed in a cylindrical body (exterior case) 4, a tip portion of each lead wire 1 is straightened. From the direction, it is pressed and compressed to form the enlarged portion 30, and the concave portion 3 is formed on the end surface thereof. Enlargement part 3
The molding method of 0 may be batch press molding or stepwise molding. The shape of the enlarged portion 30 is designed in relation to the tubular shape of the tubular body (exterior case) 4 to be loaded. It is preferable to form the sliding contact side surface 31 on the peripheral edge of the enlarged portion 30. Next, the concave portions 3 of the pair of lead wires 1 are made to face each other in a straight line direction, and a temperature sensitive element 2 having a predetermined length is abutted and welded to a gap between the two to form a temperature sensitive element wire. In the following, the temperature-sensitive element wire refers to one in which the temperature-sensitive element 4 is soldered between the concave portions 3 of the two lead wires 1. This temperature sensitive element wire is inserted into the cylindrical body (exterior case) 4. Next, the enlarged portions 30 are positioned at both ends inside the tubular body 4 having an inner diameter substantially the same as the enlarged portion 30, and both side openings of the tubular body 4 are hermetically sealed with the adhesive 5.

When the temperature sensing element wire is inserted into the tubular body (exterior case) 4, the enlarged portion 30 at the tip of the lead wire 1 is designed to fit relatively tightly into the tubular body (exterior case) 4. The temperature sensitive element 2 can be easily centered in the center of the tubular body (exterior case) 4 and can be inserted straight without distortion and reliably.

Moreover, the temperature sensing element wire is inserted into the tubular body (exterior case) 4 by the enlarged portion 30 at the tip of the lead wire 1, and the openings at both ends of the tubular body (exterior case) 4 are bonded with epoxy resin or the like. When the adhesive 5 is sealed and adhered, the enlarged portion 30 at the tip of the lead wire 1 serves as a stopper to prevent the adhesive 5 from flowing into the cylindrical body (exterior case) 4 and to the temperature sensitive element 2. Adhesive 5
To prevent contact.

When the thermal fuse operates in response to the set temperature, the melted fragments of the temperature sensitive element 2 collect on the end faces of both the lead wires 1 (due to the leaking property of the solder), but the cutting assembly is incomplete. Sparks and fever may occur if there is any or if the gathering speed is slow. In the thermal fuse of the present invention, since the surface area of the end surface of the enlarged portion 30 at the tip of the lead wire 1 is very large compared to the cross-sectional area of the lead wire 1, the fragments melted in response to the set temperature are as shown in FIG. In addition, a large quantity of balls are instantly gathered on the end faces of both the lead wires 1 to form a ball 6 and a complete gap space 7 is formed, which is a temperature fuse having good sensitivity and reliable performance.

[0015]

The present invention has the above-described constitutional effects and has the following unique technical effects. a When the tip of the lead wire is compressed and expanded, and the end surface is provided with a recess, the two lead wires and the end surface of the temperature sensitive element, which are indispensable when manufacturing a thermal fuse, are abutted and soldered. There is no misalignment that occurs in the first place, so no special jig or tool is required to eliminate the misalignment. Even if you do not have a high level of skill or skill, both of the facing recesses can easily serve as a tray and a guide on a straight line of the temperature sensitive element,
Moreover, the soldering work can be performed by surely abutting. b During the assembly of the thermal fuse, when inserting the temperature sensing element wire into which the temperature sensing element is soldered in the linear direction in the concave portion at the tip of the two lead wires into the cylindrical body (exterior case), If the enlarged part of the lead wire is designed to fit into the cylinder (exterior case), the center of the lead wire and the center of the lead wire will match, so there is no need for special tools or jigs. It can be easily aligned and inserted without special skill or skill. c When the openings at both ends of the tubular body (exterior case) into which the temperature sensitive element wires are inserted are hermetically adhered with an adhesive, the enlarged portion of the lead wire acts as a plug, and the width of the tubular body (exterior case) To prevent the adhesive from flowing into the device, prevent the adhesive from adhering to the temperature-sensitive element wire, and improve the performance of the thermal fuse.
Product yield can be increased. Since the area of the enlarged portion at the tip of the lead wire is large compared to the cross-sectional area of the lead wire, fragments of the temperature sensitive element that melted and fractured in response to the set temperature are instantaneously gathered at the enlarged portions of both lead wires. Since a large amount of bulbs are formed, the breaking speed of the thermal fuse is increased, and a highly sensitive thermal fuse that reliably breaks the electric circuit connected thereto can be manufactured. eThe reaction speed at which the set temperature of the thermal fuse for large current reaches the center of the temperature sensitive element and melts and fractures, the temperature sensitive element of one thickness corresponding to the current capacity is soldered to the lead wire. Rather, when several thin temperature sensitive elements having a cross-sectional area comparable to the same electric capacity are collectively soldered, they react more reliably and quickly and melt and break. Multiple temperature sensitive elements,
Thermal fuses that are soldered together in the proper orientation and location can meet speed requirements.

As described above, in the thermal fuse and the method of manufacturing the thermal fuse according to the present invention, the lead wire having the enlarged tip and the concave portion on the end surface is developed, and the temperature sensitive element is connected to the lead wire. With this, the performance of the thermal fuse is improved, the sensitivity is ensured, the cost of the thermal fuse is reduced, and the yield is improved.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an embodiment of a thermal fuse according to the present invention.

FIG. 2 is an enlarged cross-sectional view of a tip portion of a lead wire.

FIG. 3 is a side cross-sectional view showing various examples of a lead wire distal end enlarged portion and an end view of the lead wire. A is a trumpet shape, B is a nail head shape, C is a star shape, and D is an example having a cross-shaped end surface.

FIG. 4 is a side view of a temperature sensing element line of a thermal fuse provided with a plurality of temperature sensing elements.

FIG. 5 is a side view of a temperature-sensitive element wire of a temperature fuse in which a plurality of temperature-sensitive elements are twisted and provided.

FIG. 6 is a process drawing showing the method of manufacturing the thermal fuse according to the present invention.

FIG. 7 is a side cutaway view showing a fused and fractured state of the thermal fuse according to the present invention.

[Explanation of symbols]

 1 Lead Wire 2 Temperature Sensitive Element (Special Alloy Wire) 30 Lead Wire Enlarged Part 31 Sliding Contact Side Edge of Enlarged Part 3 Recess 4 Cylinder (External Case) 5 Adhesive 6 Bonding 7 Gap Space

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[Procedure amendment]

[Submission date] March 4, 1992

[Procedure Amendment 2]

[Document name to be amended] Statement

[Name of item to be corrected] Full text

[Correction method] Change

[Correction content]

[Document name] Statement

Title: Thermal fuse and method of manufacturing thermal fuse

[Claims]

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermal fuse and a method for manufacturing the thermal fuse. What is a thermal fuse?
It is not directly related to the amount of current flowing in the connected electric circuit, and when the ambient temperature rises to a certain temperature, the alloy of special composition (hereinafter referred to as the temperature sensitive element) incorporated in the case is automatically It is the name of an electrical component that has the function of melting itself and breaking the electrical circuit connected to it. In particular, the present invention relates to a cylindrical packaged thermal fuse having a lead wire with a special tip shape, which has a great effect on quality improvement and cost reduction, and a manufacturing method thereof.

[0002]

2. Description of the Related Art Conventional thermal fuses suffer from many structural difficulties due to the structural defects described below, and their countermeasures are difficult. Various developments have been made to maintain the sensitivity and performance of the thermal fuse, but on the contrary, it causes a cost increase and hinders the reduction of manufacturing cost.

[0003]

The conventional thermal fuse has the following structural and manufacturing defects. The basic temperature fuse, the temperature sensing element lines (combined butt the temperature sensitive element in the straight line direction between the two leads, which was respectively soldered, hereinafter referred to as temperature sensitive element line) build At the time, when soldering each lead wire and the temperature sensitive element, the end faces of the comrades were carefully abutted to each other so that the centers of the comrades would not be misaligned. Because of this, there were many misalignments and many tools and jigs were required to deal with it, and high skill and skill were required. Especially when the lead wire or the temperature sensitive element is thin (there are many types of thickness of the lead wire and the temperature sensitive element depending on the current capacity), the wire is weak and the core is liable to be misaligned. Requires advanced technology and skill,
I needed more advanced tools and jigs. When inserting the soldered temperature sensitive element wire into the cylinder (exterior case), advanced tools and jigs are required to align the center of the cylinder (exterior case) with the center of the temperature sensitive element wire. Yes The work required a high level of skill and skill. When the openings at both ends of the tubular body (exterior case) into which the temperature sensitive element wire is inserted are sealed and adhered with an adhesive, there is a difficulty in preventing the inflow of the adhesive. This is because if the adhesive adheres to the temperature-sensitive element, the performance and sensitivity of the thermal fuse will deteriorate, resulting in a defective product and a reduction in yield. The temperature sensitive element soldered between the two lead wires reacts to the set temperature, melts and breaks, and the melted fragments collect on both lead wires, interrupting the electric circuit energized there. However, the solder (the temperature-sensitive element is designed to melt at a predetermined temperature and is a special solder of a specially mixed alloy) has a leakability (when the solder melts, it spreads and spreads). Due to the leakiness of the lead wire), the lead wires end up condensing on the end surface of the lead wire, and the speed of the leaking property and the amount of the collected fragments are proportional to the cross-sectional area of the lead wire. In addition, there is a limit to the amount of fragments that can be collected on the lead wire, which has been a barrier to further improvement in sensitivity and performance of the thermal fuse. Further, the thermal fuse for large current is soldered by directly abutting a single lead wire having a thickness suitable for the current value and the temperature sensitive element. However, it is certain that the reaction of the thermal fuse of the same electric capacity that reacts to the same set temperature is transmitted to the center of one thick temperature sensitive element and melts and fractures, and that several thin temperature sensitive elements melt and fracture. Moreover, it reacts quickly.
It has been considered more difficult to bond a plurality of temperature sensitive elements to a lead wire.

The present invention solves the problems as described above. The tip of the lead wire is compressed and expanded, and the end face is molded into a recess, whereby the temperature is sensed in the recess. The tip of the element can be received and easily abutted and soldered without misalignment, and the enlarged portion of the tip can be fitted into the cylinder (outer case) to facilitate centering, and the enlarged portion can be plugged. It prevents the inflow of adhesive and improves the performance of the thermal fuse, and the large surface of the expanded portion collects molten fragments instantly and in large quantities on both lead wires to form a ball. An object of the present invention is to provide a thermal fuse and a method for manufacturing the thermal fuse, which can improve the sensitivity and can significantly improve the yield. The concave portion at the tip of the lead wire is not limited to one temperature-sensitive element, but can be formed to have a size or a plurality of concave portions into which a plurality of temperature-sensitive elements can be put together. When soldering several thin temperature sensitive elements for large current all together, if a curved recess is used, several thin temperature sensitive elements will not be dispersed and can be collected and soldered in the center of the recess of the lead wire. it can. It should be noted that although some shapes of the tip end portion are disclosed, the shape and size thereof can be appropriately designed or changed.

[0005]

In order to achieve the object of providing a highly sensitive and economical thermal fuse, the present invention has developed the following structure. When the lead wire and the temperature-sensitive element are butted against each other and soldered, the tip of the lead wire is compressed and expanded from the linear direction to prevent misalignment, and a special shape such as a dish Then, the flat end surface is molded into a recess, and the recess is used as a tray to receive the temperature sensitive element. With this configuration, butt soldering can be performed without mutual misalignment of the lead wires. The tip of the lead wire is not necessarily limited to a dish shape, but can be designed in a trumpet shape, a star shape, or flattened like a nail head, and the tip of the temperature sensing element can be locked to the end surface. It suffices if a concave portion is provided. The enlarged portion of the tip portion of the lead wire is designed to have an appropriate size and thickness, and is inserted into both ends of the cylindrical body (exterior case). With this configuration, the cylindrical body (exterior case) and the temperature-sensitive element wire can be easily centered. No special tools or jigs are required, neither advanced technology nor skill is required. In the manufacturing process, when the temperature sensitive element wires are sealed and adhered to the openings at both ends of the cylindrical body (exterior case) with the adhesive, the enlarged portions of the lead wires are arranged so as to function as plugs. With this configuration, the inflow of the adhesive is prevented and the adhesive is not brought into contact with the temperature sensitive element lines, so that the yield can be improved without deteriorating the performance of the thermal fuse. The tip of the lead wire is enlarged. When the thermal fuse actually operates, that is, when the temperature sensitive element soldered between the two lead wires reaches the set temperature of the external temperature, the fragments of the temperature sensitive element that have reacted and melted, It is best to instantly gather and condense on the end faces of both lead wires, and the enlarged part at the tip of the lead wire has a much larger cross-sectional area ratio than the lead wire itself, so the solder leakage property spreads. A thermal fuse with good performance and sensitivity can be manufactured. The lead wire has a concave portion at the tip. Several thin temperature-sensing elements, which have a cross-sectional area equal to that of one thick temperature-sensing element, react faster and reliably melt and break. It is possible to collectively press several thin temperature sensitive elements against the concave portion of the lead wire, and collect several thin temperature sensitive elements in the central portion of the concave portion of the lead wire for soldering without dispersing them. The thickness and the number of thin temperature sensitive elements can be appropriately designed according to their electric capacity,
Also, several can be twisted together.

According to the present invention, in a thermal fuse in which a temperature sensitive element is connected between a pair of lead wires and enclosed in a cylinder,
A thermal fuse is proposed in which the ends of the lead wires facing each other are enlarged portions provided with a concave portion, and a temperature sensitive element is welded to the concave portion. Similarly, in a thermal fuse in which a temperature sensitive element is connected between a pair of lead wires and enclosed in a cylindrical body, the leading end of the lead wire is an enlarged portion having a recessed portion at the center, and the recessed portion has a same or different current capacity. Book temperature sensor,
In other words, a temperature fuse is proposed in which temperature sensitive elements having the same diameter or different diameters are welded.

Further, as a manufacturing method thereof, in a method of manufacturing a thermal fuse in which a single or a plurality of temperature sensitive elements are connected between a pair of lead wires and enclosed in a cylindrical body, the tip end of each lead wire is applied in a straight line direction. A pressure-compressed portion is formed as an enlarged portion, and a concave portion is formed on the end surface of the enlarged portion. The concave portion is made to face in a straight line direction and a temperature-sensitive element of a predetermined length is abutted and welded to form a temperature-sensitive element wire. A method of manufacturing a thermal fuse, characterized in that the enlarged portions are positioned at both ends of a cylindrical body having an inner diameter substantially the same as the portion and sealed with an adhesive.

In the thermal fuse having this structure, the temperature sensitive element is abutted against the concave portion of the end face of the lead wire,
It is possible to regulate the mounting direction and solder at uniform positions. The concave portion serves as a tray for the temperature sensitive element, and the core is prevented from being displaced. Further, if the enlarged portion at the tip of the lead wire is designed to fit into the tubular body (exterior case), the tubular body (exterior case) and the temperature-sensitive element wire can be easily aligned with each other. Furthermore, when the openings at both ends of the tubular body (exterior case) into which the temperature sensitive element wire is inserted are sealed and adhered, the enlarged portion of the lead wire acts as a stopper to prevent the inflow of the adhesive. To do.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a thermal fuse and a method of manufacturing a thermal fuse according to the present invention will be described with reference to the drawings.
In the embodiment shown in FIG. 1, in a thermal fuse in which a temperature sensitive element 2 such as a special alloy wire is connected between a pair of lead wires 1 and enclosed in a cylindrical body (exterior case) 4, the tip of the lead wire 1 is located at the central portion. The thermal fuse is characterized in that the temperature sensing element 2 is inserted and welded in the recess 3 as the enlarged portion 30 in which the recess 3 is provided. Reference numeral 5 in the figure denotes an adhesive such as an epoxy resin, which closes and seals both ends of the tubular body (exterior case) 4. The inner diameter Y of the cylindrical tubular body (exterior case) 4 and the outer diameter of the enlarged portion 30 at the tip of the lead wire 1 are substantially the same, and the shape thereof is formed into a disk shape that fits into the cylindrical space. The lead wire 1 is molded by pressing and compressing one end of the lead wire 1 from the linear direction as shown by an arrow in FIG. 2 (enlarged view) to expand it into a dish shape, and provide a recess 3 in the end face thereof. It is a thing. Further, it is also possible to change the design of the structure in which the enlarged tip portion 30 is molded as a separate component of a disk body having the recesses 3 formed on both sides and the lead wire 1 is bonded to one side. The shape of the enlarged tip portion 30 is shown as a dish, but various shapes such as a trumpet shape, a star shape, and a nail head shape can be designed as in each example of FIG. 3ABCD.

The thickness of the lead wire 1 and the size of the deep plate-shaped or trumpet-shaped enlarged portion 30 should be adjusted according to the current flowing therethrough.
The size and depth of the recess 3 can be appropriately designed according to the thickness of the temperature sensitive element 2. The concave portion 3 may have a curved and dented shape, or a dovetail shape. The recess 3 is
Depending on the case, a plurality of large and small pieces may be formed. If a plurality of concave portions 3 are provided, not only one temperature sensing element 2 but also a plurality of temperature sensing elements 2 having the same or different current capacity, that is, a plurality of temperature sensing elements having the same diameter or different diameters. 2 can also be welded. FIG. 4 is a side view showing a state where several thin temperature sensitive elements 2 are collectively soldered, and FIG. 5 is a side view showing a state where several temperature sensitive elements 2 are twisted together. If the temperature sensitive element 4 is fitted to the concave portion 3 at the tip of the lead wire 1 having such a shape and heated by a soldering iron or the like, it does not require high skill or skill, and does not require special tools or jigs. It is possible to perform soldering by linearly contacting each other without causing misalignment.

FIG. 6 is a process chart showing a method of manufacturing a thermal fuse. The production method is a method of manufacturing a thermal fuse encapsulated by connecting one or more of the temperature sensitive device 2 cylindrical body (outer case) 4 between a pair of lead wires 1, the leading end of each lead 1 The compressed portion is compressed in the linear direction to form the enlarged portion 30, and the concave portion 3 is formed on the end surface thereof. Enlargement part 3
The molding method of 0 may be batch press molding or stepwise molding. The shape of the enlarged portion 30 is designed in relation to the tubular shape of the tubular body (exterior case) 4 to be loaded. It is preferable to form the sliding contact side surface 31 on the peripheral edge of the enlarged portion 30. Next, the concave portions 3 of the pair of lead wires 1 are made to face each other in a straight line direction, and a temperature sensitive element 2 having a predetermined length is abutted and welded to a gap between the two to form a temperature sensitive element wire. In the following, the temperature-sensitive element wire refers to one in which the temperature-sensitive element 4 is soldered between the concave portions 3 of the two lead wires 1. This temperature sensitive element wire is inserted into the cylindrical body (exterior case) 4. Next, the enlarged portions 30 are positioned at both ends inside the tubular body 4 having an inner diameter substantially the same as the enlarged portion 30, and both side openings of the tubular body 4 are hermetically sealed with the adhesive 5.

When the temperature sensing element wire is inserted into the tubular body (exterior case) 4, the enlarged portion 30 at the tip of the lead wire 1 is designed to fit relatively tightly into the tubular body (exterior case) 4. The temperature sensitive element 2 can be easily centered in the center of the tubular body (exterior case) 4 and can be inserted straight without distortion and reliably.

Moreover, the temperature sensing element wire is inserted into the tubular body (exterior case) 4 by the enlarged portion 30 at the tip of the lead wire 1, and the openings at both ends of the tubular body (exterior case) 4 are bonded with epoxy resin or the like. When the adhesive 5 is sealed and adhered, the enlarged portion 30 at the tip of the lead wire 1 serves as a stopper to prevent the adhesive 5 from flowing into the cylindrical body (exterior case) 4 and to the temperature sensitive element 2. Adhesive 5
To prevent contact.

When the thermal fuse operates in response to the set temperature, the melted fragments of the temperature sensitive element 2 collect on the end faces of both the lead wires 1 (due to the leaking property of the solder), but the cutting assembly is incomplete. Sparks and fever may occur if there is any or if the gathering speed is slow. In the thermal fuse of the present invention, since the surface area of the end surface of the enlarged portion 30 at the tip of the lead wire 1 is very large compared to the cross-sectional area of the lead wire 1, the fragments melted in response to the set temperature are as shown in FIG. In addition, a large quantity of balls are instantly gathered on the end faces of both the lead wires 1 to form a ball 6 and a complete gap space 7 is formed, which is a temperature fuse having good sensitivity and reliable performance.

[0015]

The present invention has the above-described constitutional effects and has the following unique technical effects. a When the tip of the lead wire is compressed and expanded, and the end surface is provided with a recess, the two lead wires and the end surface of the temperature sensitive element, which are indispensable when manufacturing a thermal fuse, are abutted and soldered. There is no misalignment that occurs in the first place, so no special jig or tool is required to eliminate the misalignment. Even if you do not have a high level of skill or skill, both of the facing recesses can easily serve as a tray and a guide on a straight line of the temperature sensitive element,
Moreover, the soldering work can be performed by surely abutting. b During the assembly of the thermal fuse, when inserting the temperature sensing element wire into which the temperature sensing element is soldered in the linear direction in the concave portion at the tip of the two lead wires into the cylindrical body (exterior case), If the enlarged part of the lead wire is designed to fit into the cylinder (exterior case), the center of the lead wire and the center of the lead wire will match, so there is no need for special tools or jigs. It can be easily aligned and inserted without special skill or skill. c When the openings at both ends of the tubular body (exterior case) into which the temperature sensitive element wires are inserted are hermetically adhered with an adhesive, the enlarged portion of the lead wire acts as a plug, and the width of the tubular body (exterior case) To prevent the adhesive from flowing into the device, prevent the adhesive from adhering to the temperature-sensitive element wire, and improve the performance of the thermal fuse.
Product yield can be increased. Since the area of the enlarged portion at the tip of the lead wire is large compared to the cross-sectional area of the lead wire, fragments of the temperature sensitive element that melted and fractured in response to the set temperature are instantaneously gathered at the enlarged portions of both lead wires. Since a large amount of bulbs are formed, the breaking speed of the thermal fuse is increased, and a highly sensitive thermal fuse that reliably breaks the electric circuit connected thereto can be manufactured. eThe reaction speed at which the set temperature of the thermal fuse for large current reaches the center of the temperature sensitive element and melts and fractures, the temperature sensitive element of one thickness corresponding to the current capacity is soldered to the lead wire. Rather, when several thin temperature sensitive elements having a cross-sectional area comparable to the same electric capacity are collectively soldered, they react more reliably and quickly and melt and break. Multiple temperature sensitive elements,
Thermal fuses that are soldered together in the proper orientation and location can meet speed requirements.

As described above, in the thermal fuse and the method of manufacturing the thermal fuse according to the present invention, the lead wire having the enlarged tip and the concave portion on the end surface is developed, and the temperature sensitive element is connected to the lead wire. With this, the performance of the thermal fuse is improved, the sensitivity is ensured, the cost of the thermal fuse is reduced, and the yield is improved.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an embodiment of a thermal fuse according to the present invention.

FIG. 2 is an enlarged cross-sectional view of a tip portion of a lead wire.

FIG. 3 is a side cross-sectional view showing various examples of a lead wire distal end enlarged portion and an end view of the lead wire. A is a trumpet shape, B is a nail head shape, C is a star shape, and D is an example having a cross-shaped end surface.

FIG. 4 is a side view of a temperature sensing element line of a thermal fuse provided with a plurality of temperature sensing elements.

FIG. 5 is a side view of a temperature-sensitive element wire of a temperature fuse in which a plurality of temperature-sensitive elements are twisted and provided.

FIG. 6 is a process drawing showing the method of manufacturing the thermal fuse according to the present invention.

FIG. 7 is a side cutaway view showing a fused and fractured state of the thermal fuse according to the present invention.

[Explanation of reference numerals] 1 lead wire 2 temperature sensitive element (special alloy wire) 30 tip enlarged portion of lead wire 31 sliding side surface of peripheral edge of enlarged portion 3 recessed portion 4 cylindrical body (exterior case) 5 adhesive agent 6 bulb 7 void space

Claims (3)

[Claims] 1. In a thermal fuse in which a thermosensitive element is connected between a pair of lead wires and enclosed in a cylinder, the ends of the opposing lead wires are enlarged portions provided with concave portions, and the thermosensitive elements are welded to the concave portions. A thermal fuse characterized in that 2. In a thermal fuse in which a temperature sensitive element is connected between a pair of lead wires and enclosed in a cylindrical body, the leading end of the lead wire is an enlarged portion provided with a recessed portion in the central portion, and the recesses have the same current capacity. Alternatively, a thermal fuse characterized by welding a plurality of different temperature sensitive elements. 3. A method for manufacturing a thermal fuse in which a single or a plurality of temperature sensitive elements are connected between a pair of lead wires and enclosed in a cylindrical body, the tip end portion of each lead wire is compressed and expanded from a linear direction to expand. And a concave portion is formed on the end face of the concave portion, the concave portions are made to face each other in a linear direction, and a temperature-sensitive element of a predetermined length is abutted and welded to form a temperature-sensitive element wire. Positioning the enlarged portions at both ends of a cylinder having an inner diameter of
A method of manufacturing a thermal fuse, which comprises sealing with an adhesive.