CN217881390U

CN217881390U - Thermal fuse

Info

Publication number: CN217881390U
Application number: CN202221377032.XU
Authority: CN
Inventors: 洪尧祥; 陈春水; 黄荣钦
Original assignee: Xiamen Set Electronics Co Ltd
Current assignee: Xiamen Set Electronics Co Ltd
Priority date: 2022-06-02
Filing date: 2022-06-02
Publication date: 2022-11-22
Anticipated expiration: 2032-06-02

Abstract

The utility model relates to a thermal fuse, which comprises a shell, fusible alloy, a fluxing fusing agent and two lead wires; one end of the lead is provided with an end socket, and the end socket is provided with a groove; two ends of the fusible alloy are respectively connected with the ends of the two leads; the fusing assistant agent is coated on the outer side of the fusible alloy; the fusible alloy, the fluxing agent and the end are all arranged in the shell. The utility model discloses technical scheme sets up the end in the contact position of fusible alloy and lead wire, sets up the recess on the end, because the groove has capillary phenomenon, has the adsorption affinity to the easy gold utensil that fuses when fusible alloy fuses, and then makes the speed that fusible alloy fuses the end accelerate, and the opening part can accept partly fusible alloy, makes the disconnection distance strengthen. For the high-current thermal fuse, the ratio of the length to the diameter of the fusible alloy can be reduced, so that the overall length of the thermal fuse is reduced, and the fusing capability of a product is improved.

Description

Thermal fuse

Technical Field

The utility model relates to a safety protection circuit technical field especially relates to a fuse.

Background

A thermal fuse, also called a thermal fuse, is a temperature-sensitive circuit breaker. The temperature fuse can sense the overheating generated in the abnormal operation of the electric and electronic products, thereby cutting off the loop to avoid the fire. Is often used in electric appliances such as electric hair dryers, electric irons, electric cookers, electric furnaces, transformers, motors, drinking water dispensers, coffee makers and the like. The existing thermal fuse generally comprises a shell, a fusible alloy wire and two metal leads, wherein the fusible alloy wire is positioned in the shell, two ends of the fusible alloy wire are respectively connected and conducted with the two metal leads, the metal leads penetrate out of the shell, and the side surface of the fusible alloy wire is wrapped with a fuse-assisting agent.

In the prior art, in order to meet the requirement that the fusible alloy can be quickly shrunk to the metal leads on two sides when fused, the size of the fusible alloy is generally at least 3 according to the length-to-diameter ratio: 1, in the first order. In the existing temperature fuse, the effective coefficient of the absorption of the fusible alloy is generally 0.75, the relationship between the absorption surface Sd and the absorption height Hd of the fusible alloy at the metal pin connection part, the length L of the fusible alloy and the radius r of the fusible alloy is as follows: sd Hd 0.75 > Lpi r ² In order to increase the size of the fusible alloy absorbing surface, the size of the end surface of the pin contacting the fusible alloy is increased. In the application occasion of large current, the overall axial dimension of the temperature fuse is longer due to the length of the fusible alloy and the requirement of the absorption space. Such an elongated structure makes it impossible to use such a thermal fuse in applications where axial installation space is required.

SUMMERY OF THE UTILITY MODEL

Therefore, the fuse is needed to be provided aiming at the problems of overlong current high-current temperature fuse and inconvenience in installation and use.

A thermal fuse comprises a shell, a fusible alloy, a fluxing agent and two leads; one end of the lead is provided with an end head, and a groove is formed in the end head; two ends of the fusible alloy are respectively connected with the ends of the two leads; the fusing assistant agent is wrapped on the outer side of the fusible alloy; the fusible alloy, the fluxing agent and the end are all arranged in the shell.

Furthermore, the end head is of a boss structure with a cross section larger than that of the lead at other positions; the groove is formed by inwards sinking from the side wall of the end head.

Furthermore, the groove is in a V-shaped groove, a U-shaped groove or an inverted trapezoidal groove, and the end face of the end head is welded with the fusible alloy; the inner side wall of the groove and the side wall of the end head form an included angle of 30-90 degrees.

Furthermore, the groove is a recess which is recessed from the end face of the end head along the axial direction.

Further, the end head and the lead are integrally formed, the size of the cross section of the end head is the same as that of the other positions of the lead, and the end face of the end head is welded with the fusible alloy.

Further, a ratio of an axial length of the fusible alloy to a diameter length of the fusible alloy is less than or equal to 2.

Furthermore, the number of the grooves is multiple, and the grooves are uniformly distributed on the end head at equal intervals.

Furthermore, a wrapping shell is arranged between the fusing assistant agent and the shell.

Further, the wrapping shell comprises a first shell and a second shell which are provided with buckles; the first shell and the second shell are buckled with each other to form an accommodating cavity, the fusible alloy, the fluxing agent and the end are arranged in the accommodating cavity, and the lead is led out from the accommodating cavity and the shell; wherein, the shell is integrally formed by injection molding of a thermosetting material.

The utility model discloses technical scheme sets up the end at the contact position of fusible alloy and lead wire, sets up the recess on the end, because groove has capillary phenomenon, has the adsorption affinity to the easy gold utensil that fuses when fusible alloy fuses, and then makes fusible alloy fusing shrink the speed of end accelerate, and the opening part can receive partly fusible alloy, makes the disconnection distance strengthen. For the thermal fuse with large current, the ratio of the length to the diameter of the fusible alloy can be reduced, so that the overall length of the thermal fuse is reduced, and the fusing capability of the product is improved.

Drawings

Fig. 1 is a disassembled schematic structural view of a first embodiment of the thermal fuse of the present invention;

fig. 2 is a schematic cross-sectional view of a first embodiment of the thermal fuse of the present invention;

fig. 3 is a schematic longitudinal cross-sectional view of a first embodiment of the thermal fuse of the present invention;

FIG. 4 is a schematic diagram of various terminals of the thermal fuse of the present invention;

fig. 5 is an exploded view of an embodiment of the thermal fuse of the present invention;

fig. 6 is a schematic structural diagram of a lead wire and fusible alloy of a second embodiment of the thermal fuse of the present invention;

fig. 7 is a schematic end head structure of a second embodiment of the thermal fuse of the present invention.

In the drawings, the reference numbers indicate the following list of parts:

1. a housing; 2. a fusible alloy; 3. a fusing assistant agent; 4. a lead; 5. a tip; 51. a groove; 6. wrapping the shell; 61. a first housing; 62. a second housing.

Detailed Description

In order to make the above objects, features and advantages of the present invention more comprehensible, embodiments of the present invention are described in detail below with reference to the accompanying drawings. It is to be understood that the specific details described below are merely exemplary of some embodiments of the invention, and that the invention is capable of other embodiments than those described herein. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative work all belong to the protection scope of the present invention.

It will be understood that when an element is referred to as being "secured to" another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present. The terms "vertical," "horizontal," "left," "right," and the like as used herein are for illustrative purposes only and do not denote a single embodiment.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

In a first embodiment of the present invention, please refer to fig. 1, fig. 2, fig. 3 and fig. 5, a thermal fuse includes a housing 1, a fusible alloy 2, a fusing assistant 3 and two leads 4; one end of the lead 4 is provided with an end head 5, and the end head 5 is provided with a groove 51; two ends of the fusible alloy 2 are respectively connected with the end heads 5 of the two lead wires 4; the fusing assistant agent 3 is wrapped on the outer side of the fusible alloy 2; the fusible alloy 2, the fusing assistant 3 and the end 5 are all arranged in the shell 1.

According to the technical scheme of the utility model, the end 5 is arranged at the contact position of the fusible alloy 2 and the lead 4, the groove 51 is arranged on the end 5, the contact surface with the fusible alloy 2 is increased, and the absorption area of the fusible alloy 2 is increased; and the opening at the edge of the end part has a capillary phenomenon, so that the fusible alloy 2 has adsorption force to the fusible alloy 2 when being fused, the speed of fusing and shrinking the fusible alloy 2 to the end head 5 is accelerated, and the opening part can absorb a part of the fusible alloy 2, so that the disconnection distance is increased. For the high-current thermal fuse, the ratio of the length to the diameter of the fusible alloy 2 can be reduced, so that the overall length of the thermal fuse is reduced, and the fusing capability of a product is improved.

The embodiment of the utility model provides an in, fusible alloy 2 is cylindrical, and it is a low melting point alloy, and fusing temperature is generally less than 232 degrees, adopts fusible alloy 2 realization that present thermal fuse was used commonly. The main component of the fluxing agent 3 is rosin, which is also realized by the materials commonly used in the existing thermal fuse. Of course, the shape may be an oval, a square, or a rectangle, and is not limited to the description in the embodiment.

On the basis of the implementation, the end 5 is of a boss structure with a cross section larger than that of the lead 4 at other positions; the groove 51 is formed by recessing inward from the side wall of the tip 5. It can be understood that the boss structure can improve the axial tension and play a role in limiting; and under the condition of the same leading-out size of the electrode lead 4, the absorption area is increased, and the setting of the groove 51 accelerates the occurrence of the capillary effect; the raised boss structure may form a boundary to control the amount of fusing aid 3.

Referring to fig. 4, wherein the groove 51 extends inward from the end edge, the groove 51 may be in the shape of a V-shaped groove, a U-shaped groove or an inverted trapezoidal groove, and the end face of the tip 5 is welded to the fusible alloy 2; the inner side wall of the groove 51 and the side wall of the end head 5 form an included angle of 30-90 degrees. With such a structure, the melted fusible alloy 2 is more quickly absorbed into the groove 51 due to the capillary effect. Of course, the shape of the groove 51 may be other, which is not limited to the description in the embodiment.

In a second embodiment of the present invention, referring to fig. 6 and 7, the groove 51 is a recess recessed from the end surface of the end 5 in the axial direction. Further, the end 5 and the lead 4 are integrally formed, the cross section of the end 5 is the same as that of the lead 4, a boss structure is omitted, and the end face of the end 5 is welded with the fusible alloy 2.

In the technical scheme of the utility model, the ratio of the axial length of the fusible alloy 2 to the diameter length of the fusible alloy 2 is less than or equal to 2. Preferably, the ratio of the length to the diameter of the fusible alloy 2 thereof may be 1:1. the length of the thermal fuse is shortened through the structure, and meanwhile, the thermal fuse can be adapted to large current to be used, so that the product is more compact and convenient to install.

In order to increase the contraction speed of the fused fusible alloy 2 during fusion, the number of the grooves 51 is multiple, and the grooves 51 are uniformly distributed on the tip 5 at equal intervals.

For the above two embodiments, further, a wrapping shell 6 is provided between the fusing assistant 3 and the outer shell 1. Further, the wrapping case 6 includes a first case 61 and a second case 62 provided with a snap; first casing 61 forms one after the mutual buckle with second casing 62 and holds the chamber, and fusible alloy 2, help fusing agent 3 and end 5 all set up in holding the intracavity, and lead wire 4 draws in holding chamber and shell 1. The housing 1 is integrally injection molded from a thermosetting material.

Because the shell 1 is integrally formed by injection molding, the mold temperature needs to reach more than 170 ℃ during injection molding, and the fusing assistant 3 can be softened and flow by the high temperature of 170 ℃, so that the wrapping shell 6 is arranged, the wrapping shell 6 can adopt a mode of buckling the first shell 61 and the second shell 62, and also can adopt a mode of arranging ultrasonic welding ribs on the first shell 61 and the second shell 62 for ultrasonic welding. The method of using a coating resin may also be used. The connection manner is not described as a limitation in the present embodiment.

The shell 1 may be made of thermosetting material, and phenolic resin is generally used. Of course, it may be made of other materials, which are not limited to the description in this embodiment.

In the embodiment using the snap, the snap may be provided on the first housing 61 and the second housing 62 and elastically deformed and restored to be locked. Of course, it may also be implemented in other ways, which are not described as limitations in this embodiment.

In the embodiment, in order to ensure that the plating layer of the pin lead 4 does not peel off in the high-temperature process of injection molding, the lead 4 can be processed by nickel plating.

In one embodiment, the fusible alloy 2 can also be made into a plurality of sheet-like structures which are not in contact with each other, the fusible alloy 2 is connected between the two end heads 5 in parallel, and the auxiliary fusing agent 3 is filled in a gap between different fusible alloys 2, so that the contact area between the fusible alloy 2 and the auxiliary fusing agent 3 is increased, and the fusing shrinkage speed of the fusible alloy 2 is further increased.

The utility model discloses technical scheme, through set up recess 51 at end 5, when having increased the contact surface with fusible alloy 2, also increase fusible alloy 2 and absorb the area, and recess 51 department at end 5 edges has capillary phenomenon, thereby to easily fusing gold 2 and having the adsorption affinity when fusible alloy 2 fuses, make fusible alloy 2's fusing shrink speed accelerate, and recess 51 department can absorb a part of fusible alloy 2, make the disconnection distance strengthen, improve the breaking capacity of product.

All possible combinations of the technical features in the above embodiments may not be described for the sake of brevity, but should be considered as being within the scope of the present disclosure as long as there is no contradiction between the combinations of the technical features.

The above examples only represent some embodiments of the present invention, and the description thereof is more specific and detailed, but not to be construed as limiting the scope of the present invention. It should be noted that, for those skilled in the art, without departing from the spirit of the present invention, several changes, substitutions and improvements can be made, and all of them should be covered by the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the claims.

Claims

1. A thermal fuse, comprising: the fuse comprises a shell, fusible alloy, a fluxing agent and two leads; one end of the lead is provided with an end socket, and a groove is formed in the end socket; two ends of the fusible alloy are respectively connected with the ends of the two leads; the fusing assistant agent is wrapped on the outer side of the fusible alloy; the fusible alloy, the fluxing agent and the end head are all arranged in the shell.

2. The thermal fuse according to claim 1, wherein said tip is a boss structure having a cross-section larger than other locations of said lead; the groove is formed by inwards recessing the side wall of the end head.

3. The thermal fuse according to claim 2, wherein said recess is in the shape of a V-shaped groove, a U-shaped groove or an inverted trapezoidal groove, and the end face of said tip is welded to said fusible alloy; the inner side wall of the groove and the side wall of the end head form an included angle of 30-90 degrees.

4. The thermal fuse according to claim 1, wherein said groove is a recess recessed from an end surface of said tip in an axial direction.

5. The thermal fuse according to claim 4, wherein said tip is integrally formed with said lead wire, and wherein said tip has a cross-section of the same size as the other portions of said lead wire, and wherein said tip has an end surface welded to said fusible alloy.

6. The thermal fuse according to claim 1, wherein a ratio of an axial length of the fusible alloy to a diameter length of the fusible alloy is less than or equal to 2.

7. The thermal fuse according to claim 1, wherein the number of the grooves is plural, and the grooves are uniformly distributed on the terminal at equal intervals.

8. A thermal fuse according to any one of claims 1 to 7, wherein a wrapping sheath is provided between the fuse aid and the sheath.

9. The thermal fuse according to claim 8, wherein the pack case includes a first case and a second case provided with a snap; the first shell and the second shell are buckled with each other to form a containing cavity, the fusible alloy, the fluxing agent and the end are arranged in the containing cavity, and the lead is led out from the containing cavity and the shell.

10. The thermal fuse according to claim 8, wherein the pack case includes a first case and a second case; the first shell and the second shell are welded through ultrasonic waves to form an accommodating cavity, the fusible alloy, the fluxing agent and the end are arranged in the accommodating cavity, and the lead is led out from the accommodating cavity and the shell; wherein the shell is integrally injection molded by thermosetting materials.