A thermal cut-off device

Abstract

The utility model relates to the field of circuit protection devices, and in particular to a thermal fuse cutter. The utility model discloses a thermal fuse cutter, comprising a first electrode, a second electrode, a heating unit, a fusible alloy, an attraction electrode and a flux, wherein the first electrode and the second electrode are electrically connected through the fusible alloy, the heating unit is used to heat the fusible alloy, the attraction electrode is made of a metal material, the attraction electrode is arranged in contact with the fusible alloy, and the flux is coated on the fusible alloy and the attraction electrode or the flux is coated on the fusible alloy. The utility model arranges the attraction electrode, utilizes the wettability of the attraction electrode and the fusible alloy to attract the molten fusible alloy, and uses the flux to rapidly adsorb the molten fusible alloy to the attraction electrode, thereby improving the fusing effect of the fusible alloy and ensuring the fusing reliability.

Description

Technical Field

[0001] The utility model belongs to the field of circuit protection devices, in particular to a thermal fuse cutter. Background Art

[0002] The thermal cutoff is a protector that can act in time when an abnormality occurs, such as overcurrent and overcharging risks (when the main circuit has overcurrent or short circuit, the internal fusible alloy heats up and melts itself to cut off the power supply; the control circuit lead and the two main circuit electrode sheets form a control loop. When the main circuit has an abnormal overcharge, the control circuit is connected, and the heating sheet heats up to melt the fusible alloy and cut off the circuit). In order to improve the overcurrent capacity of the thermal cutoff, the thermal cutoff design will be enlarged to increase the size and thickness of the fusible alloy (that is, increase the cross-sectional area of ​​the fusible alloy) to improve the current carrying capacity. Increasing the size and thickness of the fusible alloy will cause a large amount of molten alloy to accumulate after the fusible alloy is controlled to melt. Since the space of the heating sheet pad is limited, it cannot absorb all the molten alloy. The molten alloy will remain on the heating sheet and cause adhesion, causing the fuse function to fail. Summary of the invention

[0003] The purpose of the utility model is to provide a thermal fuse cutoff device to solve the above-mentioned technical problems.

[0004] To achieve the above-mentioned purpose, the technical solution adopted by the utility model is: a thermal fuse cutoff, comprising a first electrode, a second electrode, a heating unit, a fusible alloy, an attraction electrode and a flux, the first electrode and the second electrode are electrically connected through the fusible alloy, the heating unit is used to heat the fusible alloy, the attraction electrode is made of metal material, the attraction electrode is arranged in contact with the fusible alloy, and the flux is coated on the fusible alloy and the attraction electrode or the flux is coated on the fusible alloy.

[0005] Furthermore, the heating unit is implemented by a heating plate, and the fusible alloy is fixedly arranged on the heating plate.

[0006] Furthermore, the fusible alloy is adhered to the first electrode, the second electrode and the heating plate and fixedly connected by welding.

[0007] Furthermore, it also includes a shell, the first electrode, the second electrode, the heating unit, the fusible alloy, the attraction electrode and the flux are arranged in the shell, and the outer ends of the first electrode and the second electrode pass through the shell and extend to the outside of the shell.

[0008] Furthermore, a positioning groove is provided on the inner side wall of the shell for positioning the attraction electrode.

[0009] Furthermore, positioning grooves are respectively provided on one of the opposite inner side walls of the shell, and the two ends of the attraction electrode are arranged in the positioning grooves.

[0010] Furthermore, the attraction electrode is provided with a plurality of openings.

[0011] Furthermore, the cross section of the attraction electrode is an arch-shaped structure, or the attraction electrode is a flat sheet structure.

[0012] Furthermore, it also includes a heat-conducting electrode sheet, which is attached to the heating unit.

[0013] Beneficial technical effects of the utility model:

[0014] The utility model arranges an attraction electrode, utilizes the wettability of the attraction electrode and the fusible alloy to attract the molten fusible alloy, and uses a flux to rapidly adsorb the molten fusible alloy to the attraction electrode, thereby improving the fusing effect of the fusible alloy and ensuring the fusing reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0016] Figure 1 This is a structural diagram of the first embodiment of the utility model;

[0017] Figure 2 A structural diagram of another perspective of the first embodiment of the utility model;

[0018] Figure 3 This is a structural diagram of the first embodiment of the utility model with the cover plate omitted;

[0019] Figure 4 This is a structural diagram of the first embodiment of the utility model with the housing omitted;

[0020] Figure 5 This is an exploded view of the first embodiment of the utility model;

[0021] Figure 6 It is a cross-sectional view of the first embodiment of the utility model;

[0022] Figure 7 This is a structural diagram of the attraction electrode of the second embodiment of the utility model;

[0023] Figure 8 This is a structural diagram of the third embodiment of the present invention with the cover plate omitted;

[0024] Fig. 9 This is a structural diagram of the third embodiment of the present utility model with the housing omitted;

[0025] Fig.10 This is the structure of the attraction electrode of the third embodiment of the present utility model. DETAILED DESCRIPTION

[0026] To further illustrate the various embodiments, the present invention provides drawings. These drawings are part of the disclosure of the present invention, which are mainly used to illustrate the embodiments and can be used in conjunction with the relevant descriptions in the specification to explain the operating principles of the embodiments. With reference to these contents, a person of ordinary skill in the art should be able to understand other possible implementations and advantages of the present invention. The components in the figures are not drawn to scale, and similar component symbols are generally used to represent similar components.

[0027] The utility model is now further described in conjunction with the accompanying drawings and specific implementation methods.

[0028] Embodiment 1

[0029] like Figure 1-6 As shown, a thermal fuse cutoff includes a housing 1, a first electrode 2, a second electrode 3, a heating unit 4, a fusible alloy 5, an attraction electrode 6 and a flux 7. The first electrode 2, the second electrode 3, the heating unit 4, the fusible alloy 5, the attraction electrode 6 and the flux 7 are arranged in the housing 1, and the outer ends of the first electrode 2 and the second electrode 3 pass through the housing 1 and extend to the outside of the housing 1. In this specific embodiment, the housing 1 is a rectangular parallelepiped structure, and the outer ends of the first electrode 2 and the second electrode 3 pass through the housing 1 and extend to the left and right sides of the housing 1 (with the outer ends of the first electrode 2 and the second electrode 3 extending to the left and right sides of the housing 1). Figure 1 In some embodiments, the housing 1 may be a cube, a cylinder or other shapes; the outer ends of the first electrode 2 and the second electrode 3 may extend from other positions of the housing 1.

[0030] The housing 1 can be made of insulating materials such as ceramic, bakelite or engineering plastics. The housing 1 includes a housing 11 with an opening at the top and a cover 12, and the cover 12 is covered on the opening of the housing 11. Preferably, the cover 12 is embedded in the opening of the housing 11 and is flush with the top of the housing 11, so that the structure is more compact and easy to assemble, but it is not limited to this. In some embodiments, the housing 1 can also be implemented by other housing structures.

[0031] In this specific embodiment, the housing 11 and the first electrode 2 and the second electrode 3 are integrally injection molded, which has good stability and is easy to assemble, but is not limited thereto.

[0032] The first electrode 2 and the second electrode 3 are located at the inner ends of the shell 1 and are spaced apart from each other and are electrically connected through the fusible alloy 5. The heating unit 4 is used to heat the fusible alloy 5. The attraction electrode 6 is made of metal material. The attraction electrode 6 is arranged in contact with the fusible alloy 5. The flux 7 is coated on the fusible alloy 5 and the attraction electrode 6.

[0033] In this specific embodiment, the heating unit 4 is implemented by using a heating sheet 41, which has a simple structure and is easy to implement. However, it is not limited thereto. In some embodiments, the heating unit 4 can also be implemented by using other existing heating structures.

[0034] The heating sheet 41 is disposed on the bottom of the housing 11 and between the inner ends of the first electrode 2 and the second electrode 3. A pad 411 is provided on the upper surface of the heating sheet 41. The fusible alloy 5 is attached to the inner ends of the first electrode 2, the inner ends of the second electrode 3, and the heating sheet 41 and is fixedly connected to the inner ends of the first electrode 2, the inner ends of the second electrode 3, and the pad 411 of the heating sheet 41 by welding. The fusible alloy 5 is directly welded and fixed to the heating sheet 41, improving the heating effect. However, it is not limited thereto. In some embodiments, a heat conducting member or the like can also be provided between the heating sheet 41 and the fusible alloy 5, and the heating sheet 41 heats the fusible alloy 5 through the heat conducting member. Specifically, in this embodiment, the fusible alloy 5 is fixedly welded together with the inner ends of the first electrode 2, the inner ends of the second electrode 3, and the pad 411 of the heating sheet 41 by reflow soldering. Of course, in some embodiments, it can also be resistance welding, ultrasonic welding, etc.

[0035] In this specific embodiment, the upper surface of the pad 411 of the heating sheet 41 (the welding surface for welding with the fusible alloy 5) is flush with the upper surfaces of the inner ends of the first electrode 2 and the second electrode 3 (the welding surfaces for welding with the fusible alloy 5), that is, in the same plane, which is convenient for the assembly and fixation of the fusible alloy 5. However, it is not limited thereto. The controlled end 412 of the heating sheet 41 passes through the bottom of the housing 11, facilitating wiring during subsequent use. The heating sheet 41 can be implemented by using an existing heating sheet, such as a ceramic heating sheet.

[0036] In this specific embodiment, the fusible alloy 5 is a tin-copper alloy, a tin-lead alloy, a tin-bismuth alloy, etc., which is easy to implement and has a good fusing effect. However, it is not limited thereto. In some embodiments, the fusible alloy 5 can also be implemented by using other alloy materials.

[0037] The attracting electrode 6 is attached to the upper surface of the fusible alloy 5, improving the absorption capacity for the molten fusible alloy 5. Preferably, the attracting electrode 6 is located above the pad 411 of the heating sheet 41, further improving the absorption effect on the molten fusible alloy 5, thereby improving the fusing effect of the fusible alloy 5.

[0038] In this specific embodiment, the attracting electrode 6 is a long strip-shaped flat sheet structure and is generally in a "king" character structure, increasing the adsorption surface area of the attracting electrode 6 and further improving the absorption effect on the molten fusible alloy 5. However, it is not limited thereto.

[0039] The front and rear inner walls of the housing 11 are respectively provided with positioning grooves 111, which penetrate to the top of the front and rear inner walls of the housing 11. The two ends of the attraction electrode 6 are respectively arranged in the positioning grooves 111 on the front and rear inner walls. The attraction electrode 6 is positioned and installed and fixed to the left and right through the positioning grooves 111, which is not only easy to assemble but also can prevent the attraction electrode 6 from moving to ensure the absorption effect of the molten fusible alloy 5. Of course, in some embodiments, the location and number of the positioning grooves 111 can be set according to actual needs.

[0040] Furthermore, both ends of the attraction electrode 6 are fixed to the positioning groove 111 by a fixing glue (such as epoxy resin), so as to further improve the stability of the attraction electrode 6 .

[0041] The melting point of the attraction electrode 6 is greater than the melting point of the fusible alloy 5, so that when the fusible alloy 5 melts, the attraction electrode 6 will not melt, thereby ensuring the absorption effect of the molten fusible alloy 5. The attraction electrode 6 can be made of metal materials such as copper, nickel, and copper alloy.

[0042] The flux 7 has the function of preventing the surface of the fusible alloy 5 from being oxidized, and under the action of its surface tension, the molten fusible alloy 5 can be quickly adsorbed to the attraction electrode 6, thereby improving the fusing effect of the fusible alloy 5.

[0043] The first electrode 2 and the second electrode 3 are made of a copper substrate, and the surface may be plated with tin, nickel or silver to increase the conductivity.

[0044] In this specific embodiment, the thermal fuse cutoff further includes a heat-conducting electrode sheet 8 , and the heat-conducting electrode sheet 8 is attached to the bottom surface of the heating sheet 41 through heat-conducting silicone grease.

[0045] When in use, the thermal cutoff is connected to the main circuit through the first electrode 2 and the second electrode 3, and the controlled end 412 of the heating plate 41 is connected to the control circuit. When the main circuit has an overcurrent or short circuit, the fusible alloy 5 generates heat and melts by itself; or when the circuit has an abnormal condition such as overcharging, the control circuit is connected, and the heating plate 41 works to heat the fusible alloy 5 to melt the fusible alloy 5. The molten fusible alloy 5 is attracted to the attraction electrode 6 through the wettability of the attraction electrode 6 and the fusible alloy 5. At the same time, the capillary phenomenon formed by the surface tension of the flux 7 is quickly adsorbed to the attraction electrode 6, so that the fusible alloy 5 melts and the power supply is cut off.

[0046] Embodiment 2

[0047] like Figure 7 As shown, the difference between this embodiment and the first embodiment is that the attraction electrode 6 of this embodiment is provided with a through hole 61 to further improve the absorption effect of the molten fusible alloy 5.

[0048] In this specific embodiment, the through holes 61 are circular holes and there are multiple through holes, but it is not limited thereto. In some embodiments, the through holes 61 may also be square holes, elliptical holes or other shapes, and the number of through holes 61 may be set according to actual needs.

[0049] Embodiment 3

[0050] like Figure 8-10 As shown, the difference between this embodiment and the first embodiment is that the attraction electrode 6 of this embodiment is a long strip structure, the cross section of the attraction electrode 6 is an arch-shaped structure, the opening direction of the cross section of the attraction electrode 6 is set, the attraction electrode 6 is set on the pad 411 of the heating plate 41 and embedded in the middle of the fusible alloy 5, thereby dividing the fusible alloy 5 into two left and right pieces, the left and right pieces of the fusible alloy 5 are electrically connected through the attraction electrode 6, the flux breaker 7 is coated on the left and right pieces of the fusible alloy 5, and the top of the attraction electrode 6 is provided with a through hole 61. The attraction electrode 6 structure has more absorption space, thereby further improving the absorption effect of the molten fusible alloy 5.

[0051] In this embodiment, the fusible alloy 5 is assembled into two pieces, which reduces the amount of fusible alloy 5 and increases the shrinkage space of the molten fusible alloy when it is melted. However, it is not limited to this. In some embodiments, the fusible alloy 5 can also be more than two pieces, such as three pieces, four pieces, etc.

[0052] The utility model arranges an attraction electrode 6, utilizes the wettability of the attraction electrode 6 with the fusible alloy 5 to attract the molten fusible alloy, and uses a flux 7 to rapidly adsorb the molten fusible alloy 5 to the attraction electrode 6, thereby improving the fusing effect of the fusible alloy 5 and ensuring the fusing reliability.

[0053] Although the present invention has been specifically demonstrated and described in conjunction with the preferred embodiments, those skilled in the art should understand that various changes may be made to the present invention in form and detail without departing from the spirit and scope of the present invention as defined in the appended claims, all of which are within the scope of protection of the present invention.

Claims

1. A thermal cutoff device, characterized in that: It includes a first electrode, a second electrode, a heating unit, a fusible alloy, an attraction electrode and a flux. The first electrode and the second electrode are electrically connected through the fusible alloy. The heating unit is used to heat the fusible alloy. The attraction electrode is made of metal material. The attraction electrode is arranged in contact with the fusible alloy. The flux is coated on the fusible alloy and the attraction electrode or the flux is coated on the fusible alloy.

2. The thermal cutoff according to claim 1, characterized in that: The heating unit is implemented by a heating plate, and the fusible alloy is fixedly arranged on the heating plate.

3. The thermal cutoff according to claim 2, characterized in that: The fusible alloy is adhered to the first electrode, the second electrode and the heating plate and fixedly connected by welding.

4. The thermal cutoff according to claim 3, characterized in that: The welding surfaces of the first electrode, the second electrode and the heating plate that are welded with the fusible alloy are in the same plane.

5. The thermal cutoff according to claim 1, characterized in that: It also includes a shell, in which the first electrode, the second electrode, the heating unit, the fusible alloy, the attraction electrode and the flux are arranged, and the outer ends of the first electrode and the second electrode pass through the shell and extend to the outside of the shell.

6. The thermal cutoff according to claim 5, characterized in that: A positioning groove is provided on the inner side wall of the shell for positioning the attraction electrode.

7. The thermal cutoff according to claim 6, characterized in that: Positioning grooves are respectively arranged on opposite inner side walls of the shell, and two ends of the attraction electrode are arranged in the positioning grooves.

8. The thermal cutoff according to claim 1, characterized in that: The attraction electrode is provided with a plurality of openings.

9. The thermal cutoff according to claim 1 or 8, characterized in that: The cross section of the attraction electrode is an arch-shaped structure, or the attraction electrode is a flat sheet structure.

10. The thermal cutoff according to claim 1, characterized in that: It also includes a heat-conducting electrode sheet, which is attached to the heating unit.

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