JP2005129432A - Fusible alloy and thermal fuse - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fusible alloy and a thermal fuse having an operating temperature of 133°C and in which a manufacturing property and durability can be improved. <P>SOLUTION: This fusible alloy contains 43.5wt% or higher and 50wt% or lower Sn and 0.1wt% or higher and 5wt% or lower In and the remaining part is composed of Bi and unavoidable impurities. The fusible alloy is used in a fuse element and provided with a pair of electrical terminals 2 and 3 connected to the fuse element, and a case 8 storing at least the fuse element; and both end surfaces of the case 8 are formed so as to be non-parallel to each other. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a fusible alloy for a fuse and a thermal fuse that are suitably used for preventing failure of an electronic device due to abnormal overheating or overcurrent.

  In order to prevent the occurrence of equipment failure due to abnormal heat generation in batteries used in mobile phones and various electronic equipment, it has become necessary to mount thermal fuses inside batteries and electronic equipment. ing. For example, in a battery, when the positive electrode and the negative electrode are short-circuited for some reason, rapid discharge occurs. The battery suddenly generates heat due to this discharge. This heat generation may cause failure or malfunction of the battery and electronic components present in the vicinity thereof. Also in chargers, battery adapters, and the like, temperature rise may occur due to heat generation, and therefore, it is required to mount thermal fuses in these chargers, adapters, and the like.

  The thermal fuse is provided with terminal portions at both ends of a fuse element made of a fusible alloy that melts when reaching a predetermined temperature, and the terminal portions are connected to a part of the circuit wiring. When an abnormal heat generation occurs in a circuit or the like, the fuse element melts at the temperature due to the abnormal heat generation. By blowing the fuse element, the conduction is cut off, and damage to the battery and other parts is avoided.

Here, since the temperature at which the thermal fuse cuts off the conduction is determined by the melting temperature of the fusible alloy constituting the fuse element, the melting temperature of the fusible alloy can be adjusted to determine the operating temperature of the thermal fuse. Necessary. Conventionally, a thermal fuse that operates at around 100 ° C. has often been required, but in recent years, a thermal fuse as a safety measure has also been required for chargers and adapters, etc. That is, a melting alloy having a melting temperature of around 133 ° C. and a thermal fuse are required to be melted.

  In addition, fusible alloys constituting conventional fuse elements often contain environmentally hazardous substances such as Pb. For this reason, conventionally, binary and ternary soluble alloys using elements of In, Sn, and Bi have been used as soluble alloys that do not use Pb, which is an environmentally hazardous substance (for example, patents). Reference 1).

  FIG. 15 is a sectional view of an axial type thermal fuse in the prior art, and FIG. 16 is a perspective view of a radial type thermal fuse in the prior art. FIG. 14 shows a so-called axial type thermal fuse, and FIG. 15 shows a so-called radial type thermal fuse.

  100 is an axial type thermal fuse, 101 is a case, 102 is a fuse element, 103 is a flux, 104 is an electrical terminal, 105 is a sealing material, and 106 is a radial type thermal fuse. A fuse element 102 made of a fusible alloy is accommodated inside the case 101, and electrical terminals 104 are connected to both ends of the accommodated fuse element 101. The electric terminal 104 is composed of a lead terminal or the like. Both ends of the case 101 are sealed with a sealing material 105 such as a resin to prevent the molten soluble alloy from flowing out of the case even when the fuse element is melted. Further, the flux 103 is disposed so as to cover the fuse element 102 and improves the fusing performance.

The same applies to the radial type thermal fuse 106, in which the fuse element and flux are accommodated in the case 101, the electrical terminal 104 is connected to the fuse element 102, and the opening provided for accommodation is sealed. Sealed with a stopper 105.
JP 2003-82430 A

  However, the melting temperature is low at the conventional composition ratio of the binary and ternary soluble alloys in which the elements of In, Sn, and Bi are used in order to avoid Pb, and 133 ° C. required for lighting equipment and the like. There is a problem that a thermal fuse having an operating temperature of cannot be constructed.

  Conventional thermal fuses are constructed by storing the fuse element in a rectangular parallelepiped, cubic shape, or cylindrical case with vertical ends, but in this case, it takes time to seal the opening of the case. Thus, there is a problem that the durability is lowered and the variation of elements is increased. In particular, since the opening is vertically vertical, it is necessary to insert a sealing material or to apply and apply a large number of sealing materials when sealing with a sealing material. It takes a lot of time. In addition, the sealing material often overflows outside the case, and the sealing material with a high coefficient of thermal expansion puts extra stress on the case and electrical terminals when the temperature rises, preventing operation at the original fusing temperature. Although the performance of the fusible alloy has been achieved, there has been a problem that the target thermal fuse having an operating temperature of around 133 ° C. cannot be realized.

  SUMMARY OF THE INVENTION The present invention solves the above-described conventional problems by using a fusible alloy for a fuse having a melting temperature of around 133 ° C. without using Pb, which is an environmentally hazardous substance, and a thermal fuse using this fusible alloy. It is an object of the present invention to provide a thermal fuse with improved durability and reduced variation.

  The present invention is configured to include Sn of 43.5 wt% to 50 wt% and In of 0.1 wt% to 5 wt% with the balance being Bi and inevitable impurities.

  According to the present invention, a fusible alloy having a melting temperature of around 133 ° C., which has been required in recent years, and a fuse element formed from this fusible alloy are realized without using Pb which is an environmentally hazardous substance.

  In addition, by making the end faces of the case of the thermal fuse non-parallel and further non-perpendicular to the longitudinal direction, the openings formed at both ends of the case have an oblique shape, and the dispenser is used when sealing this Can be used. Thereby, since a sealing process is simplified, sealing accuracy improves and durability also improves. In addition, due to the simplification of the sealing process, device variations are also reduced.

  In addition, by defining the ratio of the amount of penetration of the sealing material, it is possible to prevent the adverse effect on the fuse element inside the case due to the thermal expansion of the sealing material.

  The invention according to claim 1 of the present invention is a case for storing a fuse element formed of a fusible alloy, a pair of electrical terminals connected to the fuse element, and at least the fuse element, and both end faces of the case Are temperature fuses that are non-parallel to each other, and are temperature fuses that operate at around 133 ° C., and that the sealing material such as resin does not overflow to the outside of the case. Can do.

  The invention according to claim 2 of the present invention is characterized in that both end faces of the case that are non-parallel to each other are a projecting surface of the electrical terminal and a surface facing the projecting surface. The fuse has an effect of improving the working efficiency of sealing the opening and reducing the overflow of the sealing material to the outside of the case.

  According to a third aspect of the present invention, there is provided the thermal fuse according to any one of the first and second aspects, wherein notches are provided in at least a part of both end faces of the case that are not parallel to each other. Thus, the overflow of the sealing material that seals the opening can be further reduced.

  The invention according to claim 4 of the present invention is characterized in that at least one of both end faces of the case which are non-parallel to each other is non-perpendicular to the protruding direction of the electric terminal. Or a thermal fuse according to claim 1, wherein a discharger that discharges a sealing material when sealing the opening can be applied perpendicularly to the longitudinal direction of the case, and the sealing work efficiency is improved. It can be sealed with a small amount of sealing material.

  The invention according to claim 5 of the present invention is the thermal fuse according to any one of claims 1 to 4, wherein a side cross section along the protruding direction of the electric terminal of the case is substantially trapezoidal. Thus, when the opening is sealed, the discharger that discharges the sealing material can be applied perpendicularly to the longitudinal direction of the case, so that the sealing work efficiency is improved and sealing is performed with a small amount of the sealing material. Can do.

  The invention according to claim 6 of the present invention is characterized in that the longest portion and the shortest portion exist on the side surface along the protruding direction of the electrical terminal of the case. And by making the opening into a shape cut obliquely, the sealing work efficiency of the sealing material can be improved and the sealing material overflow can be prevented.

  According to a seventh aspect of the present invention, in the temperature fuse according to any one of the first to sixth aspects, the thermal fuse is an axial type in which a pair of electrical terminals protrude from opposite end faces of the case. A highly durable axial type fuse having an operating temperature of around 133 ° C. can be provided.

  The invention according to claim 8 of the present invention is a thermal fuse according to any one of claims 1 to 6, which is a radial type in which a pair of electrical terminals protrude from an arbitrary surface of the case. A highly durable radial type fuse having an operating temperature of around 133 ° C. can be provided.

  The invention according to claim 9 of the present invention is the temperature fuse according to any one of claims 1 to 8, characterized in that the flux is enclosed in the case and in contact with the fuse element. Thus, the fuse element has an action of promoting separation by fusing.

  The invention according to claim 10 of the present invention is the thermal fuse according to claim 9, characterized in that the case has permeability and the flux enclosed inside has a color. Automatic non-defective product determination based on the amount of sealing is possible using image recognition.

  According to an eleventh aspect of the present invention, the fusible alloy contains Sn of 43.5 wt% or more and 50 wt% or less, 0.1 wt% or more of In and 0.1 wt% or less of In, and the balance is Bi and inevitable impurities The temperature fuse according to claim 1, wherein the temperature fuse operates appropriately at around 133 ° C. 11.

The invention according to claim 12 of the present invention is Sn of 43.5 wt% or more and 50 wt% or less,
Containing 0.1 wt% or more and 5 wt% or less of In,
It is a soluble alloy characterized in that the balance is Bi and unavoidable impurities and the melting temperature is 128 ° C to 138 ° C, and has a melting temperature of 128 ° C to 138 ° C. It is possible to obtain a fusible alloy that is optimal for a thermal fuse that operates before and after.

  The invention according to claim 13 of the present invention includes 43.5 wt% or more and 50 wt% or less of Sn, 0.1 wt% or more and 5 wt% or less of In, with the balance being Bi and inevitable impurities, A fuse element characterized in that a fusible alloy having a temperature of 128 ° C. to 138 ° C. is formed into a plate-like body, a rod-like body or a linear body, and is an optimum fuse for fusing at around 133 ° C. Element can be obtained.

  Hereinafter, it demonstrates using drawing.

(Embodiment 1)
First, the relationship between the melting temperature of the soluble alloy, the liquidus temperature, and the solidus temperature will be described. When a soluble alloy is heated and melted, the phase state generally changes in the order of a solid phase, a solid-liquid coexisting phase, and a liquid phase. Here, the boundary temperature between the solid phase and the solid-liquid coexisting phase is the solid phase temperature. The boundary temperature between the solid-liquid coexisting phase and the liquid phase is the liquidus temperature. The melting temperature of the soluble alloy exists between any of these solidification temperatures and liquidus temperatures. In particular, the actual melting temperature is between the solidus temperature and the liquidus temperature, and is in the vicinity of the liquidus temperature. If the difference between the solid phase temperature and the liquid phase temperature is large, the variation in the melting temperature increases. If the difference is small, the variation decreases, and the reliability and life are increased.

  FIG. 1 is a ternary composition diagram according to Embodiment 1 of the present invention. FIG. 1 shows a ternary relationship of In, Sn, and Bi, and the numbers on each side of the triangle in the figure indicate wt% of each element. The numbers on the bottom of the triangle when looking toward FIG. 1 are the wt% values of Bi, the numbers on the right side are the wt% values of Sn, and the numbers on the left side are the wt% values of In. It is a numerical value. The broken line described inside the triangle is a line connected for each element with respect to these wt% values. The part surrounded by the solid line in the ternary composition diagram and hatched is the part satisfying the composition ratio of the soluble alloy of the present invention.

  The soluble alloy of the present invention is a ternary alloy composed of three elements of In (indium), Sn (tin), and Bi (bismuth) except for inevitable impurities. First, the reason why these three elements of In, Sn, and Bi are used for the fusible alloy will be described.

  First, In is used because In is highly effective in reducing the melting point of the soluble alloy. A normal single metal has a very high melting point and is not suitable for the purpose of a thermal fuse in which conduction is cut off by fusing. It is necessary to lower the melting point of the fusible alloy to some extent, and In is a very suitable metal element for forming the fusible alloy because of its great effect of lowering the melting point of the fusible alloy. For this reason, when it is desired to lower the melting temperature, the In composition ratio may be increased. When it is desired to increase the melting temperature, the In ratio may be decreased.

  Next, Sn is easily mixed with other elements such as Zn and In and is a suitable element for forming a uniform alloy. Further, when Sn is contained, there is an effect that the wettability of the soluble alloy is increased. When the wettability of the fusible alloy is increased, it is suitable for coating and the like, and also suitable for stretching by rolling. This is a very suitable metal element. Sn is a very inexpensive metal and is a suitable metal as a main component of the soluble alloy in order to reduce the cost of the soluble alloy.

  This is because Bi has the effect of lowering the melting point of the fusible alloy like In, and the melting temperature of the fusible alloy can be adjusted to a target temperature around 133 ° C.

  Next, the reason why the composition ratio of the fusible alloy of the present invention is assumed that In is 0.1 wt% or more and 5 wt% or less, Sn is 43.5 wt% or more and 50 wt% or less, and the balance is Bi and inevitable impurities is described. .

  First, the reason why In is 0.1 wt% or more and 5 wt% or less will be described. If In is not included at all, the effect of lowering the melting point of the fusible alloy is very weak, so that the target fusing temperature around 133 ° C. cannot be achieved. On the other hand, if it exceeds 5 wt%, the temperature difference between the liquid phase and the solid phase of the fusible alloy becomes too large, resulting in a plurality of fusing temperature peaks or too much fusing variation.

  Next, the reason why Sn is set to 43.5 wt% or more and 50 wt% or less will be described. When Sn is less than 43.5 wt%, the temperature difference between the solid phase and the liquid phase becomes too large, resulting in large fusing variations. On the other hand, if it is larger than 50 wt%, the flexibility is lost, and if it is made linear, there is a problem that it is hard and breaks, resulting in poor workability.

  In addition, since In has a higher cost than Sn, the lower the In ratio, there is a merit that leads to cost reduction.

  Bi is the remaining ratio of the composition ratio of In and Sn, and the target melting temperature can be achieved.

  From the above composition ratio, a soluble alloy having a melting temperature of about 133 ° C., more specifically, 128 ° C. to 138 ° C. can be formed.

  Here, inevitable impurities are other elements that cannot be completely prevented from being mixed during production, oxides generated during melting, and the like. Examples of other elements that may be mixed as unavoidable impurities include Al, Ag, Sb, As, Fe, Cu, Pb, and Bi.

  Next, an example in which a sample of a fusible alloy was actually produced and experimented will be described to clarify the characteristics of the fusible alloy according to the present invention.

  A fusible alloy was prepared according to a predetermined composition ratio, and a thermal fuse using a fuse element made of this fusible body was actually manufactured as a sample.

  In preparation, first, In having a purity of 99.99% or more, Sn having a purity of 99.99% or more, and Bi having a purity of 99.99% or more were weighed in a weight ratio specified for each sample, and placed in a melting furnace. I put it in. In the melting furnace, the metals are melted with sufficient time until they are completely melted. At the stage of melting, stirring is also performed to produce an alloy having a uniform distribution. After sufficiently stirring and melting, the sample was cooled at room temperature for a sufficient time to obtain a soluble alloy sample. About the obtained soluble alloy, the solidification temperature, liquidus temperature, and the difference were measured, and it was confirmed whether it had desired melting temperature and melting performance. For these confirmation experiments, DSC (differential scanning calorimeter) manufactured by Seiko Instruments Inc. was used.

  Sample 1 is a fusible alloy produced with a composition ratio of 2.5 wt% In, 40 wt% Sn, and 57.5 wt% Bi.

  Sample 2 is a fusible alloy produced with a composition ratio of 2.5 wt% In, 43.5 wt% Sn, and 54 wt% Bi.

  Sample 3 is a fusible alloy manufactured with a composition ratio of 2.5 wt% In, 50.0 wt% Sn, and 47.5 wt% Bi.

  Sample 4 is a fusible alloy produced with a composition ratio of 5.0 wt% In, 43.5 wt% Sn, and 51.5 wt% Bi.

  Sample 5 is a fusible alloy produced with a composition ratio of 5.0 wt% In, 48.0 wt% Sn, and 47.0 wt% Bi.

  Sample 6 is a fusible alloy prepared with a composition ratio of 5.0 wt% In, 50.0 wt% Sn, and 45.0 wt% Bi.

  Sample 7 is a fusible alloy produced with a composition ratio of 6.0 wt% In, 48.0 wt% Sn, and 46.0 wt% Bi.

  Sample 8 is a fusible alloy produced with a composition ratio of 9.0 wt% In, 48.0 wt% Sn, and 43.0 wt% Bi.

  Sample 9 is a fusible alloy produced at a composition ratio of 6.0 wt% In, 50.0 wt% Sn, and 44.0 wt% Bi.

  Sample 10 is a fusible alloy produced with a composition ratio of 9.0 wt% In, 50.0 wt% Sn, and 41.0 wt% Bi.

  Sample 11 is a fusible alloy produced with a composition ratio of 2.5 wt% In, 55.0 wt% Sn, and 42.5 wt% Bi.

  The experimental results of each of these samples are shown in (Table 1).

  In (Table 1), the liquidus temperature, the solid phase temperature, the liquid phase-solid phase temperature difference, remarks, and determination for each sample are written. First, in the liquidus temperature determination, it is determined whether or not the liquidus temperature is in a desired range of 128 ° C to 138 ° C. Next, in consideration of the large liquid phase-solid phase temperature difference and the variation, the determination of ◯ and X is finally made. In addition, the reason why the determination of “x” was made in the remarks for the items determined as “x”.

  In the determination of (Table 1), only the samples that were all good after taking into account the liquidus temperature and the difference, fusing variation and other problems were determined as “good”, and otherwise determined as “poor”. As is apparent from the result of this determination, samples 2 to 6 were determined as “◯”, and other than these were determined as “x”.

  As is clear from these, in Sample 1, the Sn composition is insufficient, and in Samples 7-10, the In composition ratio is high, so the liquidus temperature is too low, or the temperature difference between the liquid phase and the solid phase is large. Therefore, it is impossible to obtain a target soluble alloy having a melting temperature of 128 ° C. to 138 ° C., for example, the fusing variation increases. In the sample 11, since the Sn composition ratio is too high, there is a demerit in workability.

  Throughout the experiment, a melting temperature between 128 ° C. and 138 ° C. was confirmed. By specifying this composition range in an alloy based on a ternary composition of In, Sn, and Bi, it is possible to obtain a fusible alloy that is optimally used for a thermal fuse having a desired operating temperature of around 133 ° C. did it.

  From the above, if the soluble alloy is 0.1 wt% or more and 5 wt% or less, Sn is 43.5 wt% or more and 50 wt% or less, and the balance is Bi and inevitable impurities as defined in the present invention, the target 128 ° C. to It was confirmed that a fusible alloy having a melting temperature of 138 ° C. can be obtained.

(Embodiment 2)
2, 3 and 5 are perspective views of the fuse portion according to the second embodiment of the present invention. FIG. 4 is a cross-sectional view of the fuse portion in the second embodiment of the present invention. 1 is a fuse element, 2 and 3 are electrical terminals, 4 and 5 are welded portions, and 6 is a flux.

  The fuse element 1 is manufactured using the fusible alloy described in the first embodiment. In FIG. 2, the linear fuse element 1 will be described as an example, but various shapes such as a plate-shaped fuse element and an elliptical fuse element may be used. The fuse element 1 is a part that actually melts in a thermal fuse that will be described later, and is a part that determines the operating temperature of the thermal fuse.

  As an example of manufacturing the fuse element 1, an alloy having a predetermined composition ratio is melted, poured into a cylindrical mold or the like, and then cooled to be solidified. The solid cylindrical alloy is produced by extruding it linearly by applying high pressure with an extruder or the like and cutting it into a predetermined length.

  Lead-type electrical terminals 2 and 3 are joined to both ends of the linear fuse element 1. As shown in FIG. 3, the electrical terminals 2 and 3 are welded to both ends of the fuse element 1 by welded portions 4 and 5 and are electrically connected. As a result, the electrical terminals 2 and 3 and the fuse element 1 are electrically conducted. Here, the electrical terminals 2 and 3 are made of a material having electrical conductivity, preferably a metal, specifically, at least one simple material selected from iron, nickel, copper, aluminum, gold, silver, and tin, or those An alloy of a metal material or a metal material in which an element other than the material group is contained in at least one simple substance or alloy selected from the above material group can be used. In the welding, a metal material or the like serving as a welding material is placed on the joint, and is electrically conducted to the electrical terminals 2 and 3, and the welding material is melted by the generated heat to be welded. FIG. 4 shows a cross section of the fuse portion. W1 represents the distance between the center lines of the fuse element 1 and the electrical terminal 2, and W2 represents the distance between the center lines of the fuse element 1 and the electrical terminal 3. W1 has a certain length as shown in FIG. 4, and W2 is almost zero.

  Since the surfaces of the electrical terminals 2 and 3 are plated, the larger the area where the fusible alloy is in contact with the plated surface, the higher the effect of promoting fusing. It is desirable to shift the center.

  FIG. 5 shows a state in which the flux 6 is provided around the fuse element 1. In use, when the temperature starts to rise, the flux 6 whose melting temperature is lower than that of the fuse element 1 starts to melt first, and the fuse element 1 is divided by the surface tension of the melted and liquefied flux 6. This can be realized more effectively. The flux 6 is preferably composed mainly of rosin or the like. However, the temperature fuse case described later is made of a permeable material, so that it can be confirmed whether the flux is sufficiently contained. Something with In this case, there is a merit that a non-defective product can be determined by automatic image recognition and manufacturing inspection can be performed at low cost.

  Next, the thermal fuse in which the fuse element 1 is stored in the case and the merits of making the both ends of the case non-parallel and non-vertical will be described.

  6 is a perspective view of the case according to the second embodiment of the present invention, FIG. 7 is a perspective view of the thermal fuse according to the second embodiment of the present invention, and FIG. 8 is a perspective view of the case according to the second embodiment of the present invention. FIG. 9 is a perspective view of a thermal fuse in which both ends of the case are sealed in the second embodiment of the present invention, and FIG. 10 is a side sectional view of the thermal fuse in the second embodiment of the present invention. 11 and 12 are perspective views of the case according to Embodiment 2 of the present invention, FIG. 13 is a perspective view of a radial type thermal fuse according to Embodiment 2 of the present invention, and FIG. 6 is a perspective view of a radial type case in Embodiment 2. FIG.

  8 is a case, 8a and 8b are openings at both ends of the case, 9, 10 is a sealing material, 11 is a dispenser, 12 is a needle tip of the dispenser, and 13 is a sealing material attached to the needle tip. The case 8 is of an axial type in which electrical terminals extend from both ends.

  Both ends of the case 8 are not parallel to each other and are not perpendicular to the longitudinal direction of the case 8. That is, the cross-sectional shape of the case 8 is substantially trapezoidal, and when the longitudinal direction is viewed, the longest part and the shortest part in the case 8 exist. Here, both ends of the case 8 have openings 8a and 8b as shown in FIG. 6, and the fuse element 1 and the like are inserted from the openings 8a and 8b, and the openings 8a and 8b are sealed. A thermal fuse is produced. FIG. 7 shows a state in which a part of the fuse element 1, the flux 6, and the electric terminals 2 and 3 are accommodated in the case 8. At this time, both ends of the case 8 serving as the openings 8a and 8b are inclined with respect to the longitudinal direction.

FIG. 8 shows a process in which the openings 8a and 8b of the case 8 are sealed. The dispenser 11 is a discharge device for the sealing material 9 and is used for work for discharging and sealing a sealing material such as resin. Here, if both ends of the case 8 serving as the opening are vertical as in the prior art, it is necessary to fill the opening with the sealing material 9 in a process of inserting the needle tip 12 of the dispenser 11 from the lateral direction. It is difficult to work. Furthermore, since the process is performed by inserting the needle tip 12, there is a problem that a thermal influence is exerted on a welding material to the fuse element 1 and the electric terminals 2 and 3 inside. Furthermore, the amount of the sealing materials 9 and 10 increases, and a very large amount of the sealing material overflows on the outer sides of both ends. Here, a resin is often used as the sealing materials 9 and 10 because of problems such as ease of manufacturing process and cost. Since this resin has a large coefficient of thermal expansion, if it overflows in large quantities, the resin will thermally expand as the temperature rises during use, causing deterioration such as expanding the openings 8a and 8b of the case. There is. Alternatively, there is a problem that pressure is applied to the electric terminals 2 and 3 to deteriorate the electric terminals 2 and 3 and stress is applied to a welded portion with the fuse element 1.

  On the other hand, when both ends of the opening are slanted as in the case 8 of the present invention, the needle tip 12 of the dispenser 11 is sealed in a state where the needle tip 12 is upright to the longitudinal direction of the case 8. The stopping material can be discharged. Since the sealing material can be filled in the form in which the dispenser 11 is erected, the work can be easily performed, the manufacturing process can be facilitated, the variation of elements is eliminated, and the cost can be reduced. Furthermore, generation of bubbles or the like in the sealing material can be prevented.

  For this reason, the absolute amount of the sealing material can be reduced, and the sealing material is less likely to overflow outside the case. If there is a lot of sealing material on the outside of the case, the thermal expansion and contraction of the sealing material made of resin, etc., is repeated, so that extra stress is applied to the case 8 and the electrical terminals 2, 3, and fusing There are problems such as adversely affecting performance and causing element degradation. On the other hand, when the opening is inclined as in the present invention, sealing is completed in a short time and with a small amount of work, so that the overflow of the sealing material is reduced. This can also reduce the stress on the electrical terminals 2, 3 and the case 8 due to the thermal expansion of the sealing material, and the adverse effect on the fusing performance is reduced. Of course, there is also an effect that the element deterioration is eliminated and the durability of the thermal fuse is increased.

  FIG. 10 is a side sectional view of the thermal fuse after being sealed. L1 is the length of the longest part of the case, L2 is the length of the shortest part of the case, and the longest part and the shortest part are formed in the longitudinal direction of the case 8 by making both end faces of the case 8 slanted. I understand that K is the protruding length of the sealing material 10 based on the longest part when both ends are sealed, and P is the penetration length in which the sealing material 10 is also recessed into the case from the end surface based on the longest part of the case. It is. Here, when both ends of the case 8 are slanted as shown in FIG. 10, overflow of the sealing material to the outside of both ends can be prevented, so that P> K can always be established. Thus, by setting P> K, it is possible to prevent the influence of the thermal expansion of the sealing material having the highest thermal expansion coefficient, and it is possible to prevent deterioration of the element.

  The case 14 shown in FIG. 11 has notches 14a and 14b at both ends thereof. By providing the notches 14a and 14b, there is an effect that the sealing material is less likely to overflow to the outside of the opening. As a result, P> K described with reference to FIG. 10 is more reliably configured, and adverse effects on the element due to the thermal expansion of the sealant using the resin can be reduced. It is preferable that the below-described portions 14a and 14b are provided in a part of the case as shown in FIG. Further, at the time of sealing with the sealing material, it is preferable that the notches 14a and 14b exist in the direction in which the dispenser is applied.

  FIG. 12 shows a case of a so-called radial type thermal fuse. 15 is a case and 15a is an opening. Since the case 15 is an axial type case, the two electric terminals extend from the opening 15 a of the case 15.

  FIG. 13 shows a perspective view of the internal fuse of the axial type fuse. Reference numerals 16 and 17 denote electric terminals, both of which extend outward from the opening. 19 is a sealing material, 20 is a fuse element, which is formed from the fusible alloy described in the first embodiment, and 21 is a flux, which is attached to cover the fuse element 20 in order to make fusing more reliable. .

As is apparent from FIG. 12, the case 15 is formed with the opening 15a obliquely, so that the case 15 has the shortest part M2 and the longest part M1. That is, the case 15 is substantially trapezoidal when viewed from the side. After the fuse element 20 or the like is stored in the case 15 having the shape composed of the shortest part M2 and the longest part M1, the opening 15a is sealed with a sealing material 19 such as resin.
Sealing with completes the thermal fuse.

  At this time, the opening 15a is inclined as shown in FIG. For this reason, when sealing using a dispenser, it is not necessary to insert the needle tip of the dispenser inside the opening 15a, and it is possible to seal in a short time by applying the needle tip from above. That is, the work in sealing becomes very easy, and the processing speed can be improved. If it is a horizontal opening rather than a diagonal as in the past, in order to seal this, it takes time to spread the resin evenly by inserting the needle tip of the dispenser into the opening. Had to be processed. For this reason, the resin overflows to the outside of the case, which may cause a problem due to the thermal expansion of the resin.

  FIG. 14 shows another type of radial type case. 22 is a case and 22a is an opening. The opening 22a is a step type, and the case 22 also has the shortest part M2 and the longest part M1. It is different from the conventional case shape close to a rectangular parallelepiped or a cube.

  As shown in FIG. 14, even when the stepped opening 22a is used, when sealing with a dispenser, it is not necessary to insert the tip of the dispenser into the opening 22a, and the resin can be easily applied from the outside. Can be sealed. For this reason, the bad influence by the thermal expansion of a sealing material can also be reduced, and the time which sealing requires can also be shortened.

  As described above, the shape of the case in the thermal fuse has the shortest part and the longest part, and is set to be substantially trapezoidal when viewed from a certain side surface. Shortening is possible. As a result, the sealing accuracy is improved, and the performance is improved and the cost is reduced by improving the yield. Furthermore, there is no excess overflow of the sealing material outside the case, etc., and the stress on the case and electrical terminals due to the thermal expansion of the sealing agent made of resin etc. can be reduced, adversely affecting the fusing performance and deteriorating the element. The temperature fuse which is prevented and has high durability is realized, and the fusible alloy described in the first embodiment makes it possible to obtain a temperature fuse which operates at around 133 ° C. which is optimal for a charger and an adapter.

  In addition, the above has mainly described the so-called axial type and radial type thermal fuses, but the embodiment is provided over the substrate film, the pair of electrical terminals provided on the substrate film, and the electrical terminals. The same applies to the thin thermal fuse composed of the fuse element made of the fusible alloy described in 1 and the cover film. Even in this case, by using the fusible alloy described in the first embodiment, it is possible to configure a temperature fuse having an operating temperature of around 133 ° C. that is optimal for a power supply, an adapter, and the like. It becomes the most suitable temperature fuse to install. Of course, other than these, it is a temperature fuse that can be applied to various electric devices such as lighting devices, electric heating devices such as kotatsu, and measuring devices with a rapid temperature rise.

  A fuse element made of a fusible alloy characterized by containing 43.5 wt% or more and 50 wt% or less of Sn and 0.1 wt% or more and 5 wt% or less of In, the balance being Bi and inevitable impurities, and the shortest By using a thermal fuse using a case in which a part and a longest part exist, the thermal fuse operates at around 133 ° C. and can be applied to a thermal fuse having high yield and durability.

Ternary composition diagram in Embodiment 1 of the present invention The perspective view of the fuse part in Embodiment 2 of this invention The perspective view of the fuse part in Embodiment 2 of this invention Cross-sectional view of the fuse portion in the second embodiment of the present invention The perspective view of the fuse part in Embodiment 2 of this invention The perspective view of the case in Embodiment 2 of this invention The perspective view of the thermal fuse in Embodiment 2 of this invention The sealing process figure of the opening part of the case in Embodiment 2 of this invention The perspective view of the thermal fuse which sealed the case both ends in Embodiment 2 of this invention Side sectional view of the thermal fuse in Embodiment 2 of the present invention The perspective view of the case in Embodiment 2 of this invention The perspective view of the case in Embodiment 2 of this invention The perspective view of the radial type thermal fuse in Embodiment 2 of this invention The perspective view of the radial type case in Embodiment 2 of this invention Sectional view of an axial type thermal fuse in the prior art Perspective view of radial type thermal fuse in the prior art

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,20 Fuse element 2,3 Electric terminal 4,5 Welding part 6,21 Flux 8 Case 8a, 8b Opening part 9, 10 Sealing material 11 Dispenser 12 Needle tip 13 Sealing material 14, 22 Case 14a, 14b Notch Part 15 Case 15a, 22a Opening 16, 17 Electrical terminal 19 Sealing material 100 Thermal fuse 101 Case 102 Fuse element 103 Flux 104 Electrical terminal 105 Sealing material 106 Thermal fuse

Claims (13)

A fuse element formed of a fusible alloy;
A pair of electrical terminals connected to the fuse element;
A thermal fuse, wherein at least the fuse element is housed, and both end faces of the case are non-parallel to each other. 2. The thermal fuse according to claim 1, wherein both end surfaces of the non-parallel case are a projecting surface of the electrical terminal and a surface facing the projecting surface. 3. The thermal fuse according to claim 1, wherein a notch portion is provided in at least a part of both end faces of the non-parallel case. The thermal fuse according to any one of claims 1 to 3, wherein at least one of both end faces of the non-parallel case is non-perpendicular to a protruding direction of the electric terminal. The thermal fuse according to any one of claims 1 to 4, wherein a side cross section along the protruding direction of the electric terminal of the case has a substantially trapezoidal shape. The thermal fuse according to any one of claims 1 to 5, wherein a longest portion and a shortest portion exist on a side surface of the case along the protruding direction of the electric terminal. The thermal fuse according to any one of claims 1 to 6, wherein the thermal fuse is an axial type in which the pair of electrical terminals protrude from opposite end faces of the case. The thermal fuse according to claim 1, wherein the thermal fuse is a radial type in which the pair of electrical terminals protrude from an arbitrary surface of the case. The thermal fuse according to claim 1, wherein a flux is sealed in the case and in contact with the fuse element. The thermal fuse according to claim 9, wherein the case is permeable, and the flux sealed inside has a color. 43.5 wt% or more and 50 wt% or less of Sn,
Containing 0.1 wt% or more and 5 wt% or less of In,
The thermal fuse according to any one of claims 1 to 10, wherein the balance is a fusible alloy composed of Bi and inevitable impurities. Sn of 43.5 wt% or more and 50 wt% or less;
Containing 0.1 wt% or more and 5 wt% or less of In,
A soluble alloy characterized in that the balance is Bi and inevitable impurities, and the melting temperature is 128 ° C to 138 ° C. Sn of 43.5 wt% or more and 50 wt% or less;
Containing 0.1 wt% or more and 5 wt% or less of In,
A fuse element comprising a fusible alloy having a balance of Bi and inevitable impurities and having a melting temperature of 128 ° C. to 138 ° C. made of a plate, rod, or wire.

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