JP5981163B2 - Current fuses and electronics - Google Patents

Description

  The present invention relates to a current fuse and an electronic device using the current fuse.

  A current fuse is known as a component for protecting an electric circuit when an overcurrent flows. An example of the current fuse is a chip-type current fuse disclosed in Patent Document 1. The chip-type current fuse includes an insulating substrate, a fuse element provided on the upper surface of the insulating substrate, and electrodes provided over the upper surface, side surfaces, and lower surface of the insulating substrate. Such a chip-type current fuse is used by connecting a portion of the electrode provided on the lower surface of the insulating substrate to an external circuit.

JP 2003-151425 A

  However, in the chip-type current fuse disclosed in Patent Document 1, a fuse element is provided on the upper surface of the insulating substrate, and a portion of the electrode provided on the lower surface of the insulating substrate is connected to an external circuit. Therefore, there is a problem that energy loss increases when a current is passed through the chip-type current fuse. Specifically, there is a problem in that unnecessary resistance occurs in a portion that electrically connects the upper surface and the lower surface of the insulating substrate, that is, a portion of the electrode that is provided on the side surface of the insulating substrate. .

  The present invention has been made in view of such problems, and an object thereof is to provide a current fuse capable of suppressing energy loss when a current is passed and an electronic apparatus using the current fuse.

The current fuse of one embodiment of the present invention includes an insulating substrate, a thick portion provided on the upper surface of the insulating substrate, and a connected region connected to a wiring conductor of an external circuit on the upper surface, and the thick wall and two metal plates having upper and lower directions thickness thin walled portion than parts, each of both ends in each of the thin portions of the two metal plates has a fuse element electrically connected , Each of the thin portions of the two metal plates has an upper surface and side surfaces facing each other
A notch portion is provided in the notch portion, and both end portions of the fuse element are respectively disposed inside the notch portion .

  An electronic device according to an aspect of the present invention includes the current fuse according to the present invention, the current fuse being mounted in a mounting region with an upper surface facing down, and each of the connected regions being a wiring conductor in the mounting region. And an external circuit connected to each of them.

According to the current fuse and the electronic device of one embodiment of the present invention, the thick portion having an insulating substrate and a connected region provided on the upper surface of the insulating substrate and connected to the wiring conductor of the external circuit on the upper surface. and two metal plate having thin portions vertical thickness is less than the thick portion respectively, each of end portions, each of the thin portion of the two metal plates and a fuse element electrically connected Each of the thin portions of the two metal plates is provided with a notch that opens to the upper surface and the side surfaces facing each other, and both end portions of the fuse element are disposed inside the notch. This eliminates the need to electrically connect the upper surface and the lower surface of the insulating substrate. As a result, it is possible to suppress energy loss when a current is passed through the current fuse.

It is a perspective view which shows the example of the current fuse of one Embodiment of this invention. FIG. 2 is a cross-sectional view taken along the line X-X ′ in the current fuse shown in FIG. 1. FIG. 2 is a plan view of the current fuse shown in FIG. 1. It is sectional drawing which shows the electronic device using the current fuse shown in FIG. It is a current fuse which concerns on the modification 1, Comprising: It is a perspective view which shows the state except the brazing material inside a notch part. 10 is a perspective view showing a current fuse according to Modification 2. FIG.

  Hereinafter, a current fuse 100 and an electronic apparatus 200 using the current fuse 100 according to an embodiment of the present invention will be described with reference to the drawings.

<Configuration of current fuse 100>
As shown in FIGS. 1 to 3, a current fuse 100 according to an embodiment of the present invention includes an insulating substrate 1, two metal plates 2, 2 provided on the upper surface of the insulating substrate 1, and two metal plates 2. 2 and a metal plate 2 and an insulating member 4 surrounding the fuse element 3.

  The current fuse 100 is a component for protecting the external circuit 6 when an overcurrent flows. Specifically, the current fuse 100 is installed inside the external circuit 6 and normally functions as a conductor. When an overcurrent flows through the external circuit 6, the current fuse 100 cuts off the current flowing through the external circuit 6 by fusing the fuse element 3.

<Configuration of insulating substrate 1>
The insulating substrate 1 is an insulating substrate. The insulating substrate 1 has a quadrangular shape when viewed in plan. The insulating substrate 1 is a member for mounting the metal plate 2 on the upper surface. The insulating substrate 1 is also a member for protecting the fuse element 3 together with the insulating member 4 and the metal plate 2 when mounted on the external circuit 6 with the upper surface of the current fuse 100 facing down.

  The insulating substrate 1 is made of, for example, a ceramic material such as alumina, mullite, or aluminum nitride, a glass ceramic material, or an insulating polymer material. In addition, the thickness of the insulating substrate 1 is set to 0.1 mm or more and 1 mm or less, for example.

<Configuration of metal plate 2>
The metal plate 2 is a metal plate having a thick portion 21 and a thin portion 22. The metal plate 2 is a member for electrically connecting the current fuse 100 and the external circuit 6. Two metal plates 2 are provided on the upper surface of the insulating substrate 1 apart from each other.

  The thick portion 21 has a connected region 23 connected to the wiring conductor 62 of the external circuit 6 on the upper surface. The thin portion 22 is thinner in the vertical direction than the thick portion 21. Each of both end portions of the fuse element 3 is electrically connected to each of the thin portions 22 of the two metal plates 2.

  Since the connected region 23 is provided on the upper surface of the thick portion 21, each of the connected regions 23 is connected to the wiring conductor 62 of the mounting region 61 of the external circuit 6 with the upper surface of the thick portion 21 facing down. In this case, the thin portion 22 and the external circuit 6 are separated. Therefore, both ends of the fuse element 3 can be joined to the upper surfaces of the thin portions 22 of the two metal plates 2. For joining the thin portion 22 and the fuse element 3, for example, a brazing material such as solder is used.

Since the fuse element 3 is bonded to the upper surface of the thin portion 22, the bonding area between the fuse element 3 and the thin portion 22 is larger than when the fuse element 3 is bonded to the side surface of the thin portion 22. can do. Thereby, the resistance between the fuse element 3 and the thin portion 22 can be reduced. Therefore, it is possible to suppress the generation of heat at the joint portion between the fuse element 3 and the thin portion 22. As a result, it is possible to suppress the current fuse 100 from being insulated at the joint portion between the fuse element 3 and the thin portion 22 by melting the fuse element 3.

  In particular, when the fuse element 3 has a plate shape like the current fuse 100 of this example, the fuse element 3 The thin portion 22 can be surface bonded. Thereby, the junction area of the fuse element 3 and the thin part 22 can be enlarged more. As a result, it is possible to suppress the generation of heat at the joint portion between the fuse element 3 and the thin portion 22.

  Each of the thin portions 22 of the two metal plates 2 and 2 is located between the thick portions 21 of the two metal plates 2 and 2. As a result, the fuse element 3 provided on the upper surface of the thin portion 22 is positioned between the two thick portions 21. As a result, the two thick portions 21 partially surround the fuse element 3. For this reason, it can suppress that the fuse element 3 is damaged by the fuse element 3 contacting with the exterior. As a result, the fuse element 3 can be prevented from being blown at a temperature lower than the assumed temperature.

  The metal plate 2 is made of, for example, a metal material such as copper, silver, or nickel, or an alloy thereof. The thickness of the metal plate 2 is set, for example, such that the thick portion 21 is 0.2 mm to 1 mm and the thin portion 22 is 0.05 mm to 0.2 mm.

<Configuration of fuse element 3>
The fuse element 3 is a member for electrically insulating the two metal plates 2 and 2 when an overcurrent flows through the current fuse 100. The fuse element 3 is a member that is blown when the temperature of the fuse element 3 becomes a specific temperature or higher. The fuse element 3 is a plate-like member. Each of both end portions of the fuse element 3 is bonded to the upper surface of the thin portion 22 of the two metal plates 2.

  Since the fuse element 3 is bonded to the upper surface of the thin portion 22, a gap is formed between the fuse element 3 and the insulating substrate 1. Due to this gap, it is possible to suppress heat generated in the fuse element 3 from being conducted to portions other than the fuse element 3.

  Furthermore, since the fuse element 3 has a plate shape, the cross-sectional area when cut by a plane perpendicular to the direction of electricity flow can be reduced as compared with the case where the fuse element 3 has a rod shape. Thereby, the resistance of the fuse element 3 can be increased. As a result, the fuse element 3 can be easily melted.

  The fuse element 3 is made of, for example, a conductive material such as indium, bismuth or tin, or a mixed material such as an alloy thereof. The melting point at which the fuse element 3 is melted is set to, for example, 80 ° C. or higher and 180 ° C. or lower. The thickness of the fuse element 3 is set to, for example, 0.05 mm or more and 0.5 mm or less. The length of the fuse element 3 in the direction in which the current flows is set to, for example, 1 mm or more and 4 mm or less. The width in the direction perpendicular to the direction in which the current of the fuse element 3 flows is set to, for example, 0.1 mm or more and 1 mm or less.

<Configuration of insulating member 4>
The insulating member 4 is a member for protecting the fuse element 3 together with the metal plate 2. Two insulating members 4 are provided on the upper surface of the insulating substrate 1 so as to sandwich the two metal plates 2. Each of the insulating members 4 is composed of a portion provided with each of the two metal plates 2 and 2 and a portion located between a pair of these portions. The two insulating members 4 and 4 constitute a frame 5 that surrounds the fuse element 3 together with the thick portions 21 of the two metal plates 2 and 2. The outer peripheral surface of the frame 5 is formed on the same surface as the outer peripheral surface of the insulating substrate 1. Since the fuse element 3 is surrounded by the frame 5, the fuse element 3 can be prevented from being damaged due to the fuse element 3 coming into contact with the outside. As a result, the fuse element 3 can be prevented from being blown at a temperature lower than the assumed temperature.

  As shown in FIGS. 1 and 2, it is preferable that the insulating member 4 is configured to have a greater vertical thickness than the thick portion 21. Thus, the upper surface of the insulating member 4 can be fixed to the external circuit 6 when the current fuse 100 is mounted in the mounting region 61 of the external circuit 6 with the upper surface of the current fuse 100 facing down.

  The insulating member 4 is made of, for example, a ceramic material such as alumina, mullite, or aluminum nitride, a glass ceramic material, or an insulating polymer material. In addition, the thickness of the insulating member 4 is set to 0.2 mm or more and 1 mm or less, for example.

  The insulating member 4 in the current fuse 100 of this example is formed integrally with the insulating substrate 1. Thereby, the intensity | strength with respect to the external force of the insulating substrate 1 and the insulating member 4 can be improved.

  In the current fuse 100 according to the embodiment of the present invention, two metal plates 2. 2 are provided on the upper surface of the insulating substrate 1. The two metal plates 2. In addition, the thin portion 22 is connected to the fuse element 3. That is, the current flowing in the connected region 23 of one metal plate 2 passes through the inside of one metal plate 2, the fuse element 3, and the inside of the other metal plate 2, and then the current of the other metal plate 2. The connection area 23 is reached. Therefore, in the current fuse 100, the current flows only on the upper surface side of the insulating substrate 1. This eliminates the need to electrically connect the upper surface and the lower surface of the insulating substrate 1. As a result, energy loss when a current is passed through the current fuse 100 can be suppressed.

  Moreover, as compared with the case where the fuse element 3 and the connected region 23 are electrically connected by a conductor formed by paste screen printing, like the chip-type current fuse disclosed in Patent Document 1, In the current fuse 100 of this example, the resistance between the fuse element 3 and the connected region 23 is small. Specifically, the conductor formed by screen printing with paste has a lower density than the metal plate 2. Accordingly, the conductor formed by screen printing with paste has a higher specific resistance than the metal plate 2. For this reason, as in the current fuse 100 of the present example, the fuse element 3 and the connected region 23 are electrically connected by the metal plate 2, thereby reducing the resistance in the portion other than the fuse element 3 in the portion where electricity flows. Can be small. As a result, generation of unnecessary heat generation in the current fuse 100 can be suppressed.

<Configuration of Electronic Device 200>
The electronic device 200 includes a current fuse 100 and an external circuit 6 on which the current fuse 100 is mounted. As shown in FIG. 4, the external circuit 6 has a mounting region 61 on the top surface where the current fuse 100 is mounted. In the mounting region 61, two or more wiring conductors 62 connected to each of the connected regions 23 are provided. The current fuse 100 is mounted in the mounting region 61 of the external circuit 6 with the upper surface facing down. Each connected region 23 is connected to a separate wiring conductor 62 in the mounting region 61.

In the electronic apparatus 200 of this example, the sum of the thickness of the wiring conductor 62 and the thickness of the thick portion 21 is set equal to the thickness of the insulating member 4. As a result, the upper surface of the external circuit 6 can be brought into contact with the upper surface of the insulating member 4 whose upper surface is on the lower side, and the wiring conductor 62 and the thick portion 21 can be brought into contact with each other. Thereby, the mountability with respect to the external circuit 6 of the current fuse 100 can be improved.

  The electronic device 200 in this example can protect the electronic device 200 when an overcurrent flows through the electronic device 200 by connecting the current fuse 100 to the wiring conductor 62. Specifically, when an overcurrent flows through the electronic device 200, the current fuse 100 cuts off the current flowing through the electronic device 200 by blowing the fuse element 3.

  Furthermore, the electronic device 200 can be an electronic device 200 with good energy efficiency by connecting the current fuse 100 in which energy loss is suppressed.

  In addition, this invention is not limited to the example of above-mentioned embodiment, A various change, improvement, etc. are possible in the range which does not deviate from the summary of this invention. For example, in the present embodiment, the insulating substrate 1 and the insulating member 4 are integrally formed, but the present invention is not limited to this. Specifically, a configuration in which the insulating member 4 is bonded onto the insulating substrate 1 may be employed.

  Further, in the present embodiment, the insulating member 4 is configured such that the thickness in the vertical direction is larger than that of the thick portion 21, but is not limited thereto. Specifically, the insulating member 4 and the thick portion 21 may have the same thickness. Further, the thickness of the thick portion 21 may be larger than the thickness of the insulating member 4.

  Moreover, in this embodiment, although the fuse element 3 is exposed upwards, it is not restricted to this. Specifically, it may be sealed with a sealing material such as resin.

  Further, in the present embodiment, the insulating substrate 1 and the frame 5 have a quadrangular shape when viewed in plan, but are not limited thereto. Specifically, it may be circular or polygonal.

<Modification>
A modification of the current fuse 100 will be described. In addition, in each structure of this example, about the member which has the structure and function similar to the above-mentioned current fuse 100, the same referential mark is attached | subjected and the detailed description is abbreviate | omitted.

In current fuse 100 shown in FIGS. 1-3, but the upper surface of the thin portion 22 is formed in a uniform flat surface, if example embodiment, as shown in FIG. 5, a uniform flat upper surface of the thin portion 22 Ru configuration der it is not already on the surface.

  In the present modification, each thin portion 22 is provided with a notch portion 24 that opens on the upper surface and the side surfaces of the two thin portions 22 facing each other. Both ends of the fuse element 3 are arranged inside the notch 24. Further, a brazing material is provided inside the notch 24 so as to electrically connect the inner peripheral surface of the notch 24 and the fuse element 3.

  Thereby, not only the lower surface of the fuse element 3 but also the side surface of the fuse element 3 can be electrically connected to the thin portion 22. Thereby, resistance between the thin part 22 and the fuse element 3 can be made smaller. As a result, heat is generated at the joined portion between the fuse element 3 and the thin portion 22, and the fuse element 3 is prevented from melting and the current fuse 100 is prevented from being insulated at the joined portion between the fuse element 3 and the thin portion 22. it can.

Further, as shown in FIG. 6, the width of the fuse element 3 and the width of the notch 24 may be made uniform, and the fuse element 3 may be fitted into the notch 24. With such a configuration, without providing a brazing material in the notch 24, in addition to the electrical connection between the lower surface of the fuse element 3 and the upper surface of the notch 24, the side surface of the fuse element 3 and the notch are cut off. Electrical connection with the inner peripheral surface of the notch 24 can be performed.

1: Insulating substrate 2: Metal plate 21: Thick portion 22: Thin portion 23: Connected region 24: Notch portion 3: Fuse element 4: Insulating member 5: Frame body 6: External circuit 61: Mounting region 62: Wiring Conductor 100: Current fuse 200: Electronic device

Claims (4)

An insulating substrate;
The insulating substrate has a thick portion having a connected region on the upper surface, which is provided on the upper surface of the insulating substrate and connected to a wiring conductor of an external circuit, and a thin portion whose thickness in the vertical direction is smaller than the thick portion. Two metal plates,
A fuse element in which both ends are electrically connected to each of the thin portions of the two metal plates ;
Each of the thin portions of the two metal plates is provided with a notch that opens on the top surface and the side surfaces facing each other,
Each of the both ends of the said fuse element is each arrange | positioned inside this notch part, The current fuse characterized by the above-mentioned . Wherein each of the thin portions of the two metal plates, current fuse according to claim 1, characterized in that positioned between each of the thick portions of the two metal plates. The current fuse according to claim 2 , wherein two insulating members constituting a frame surrounding the fuse element together with each of the thick portions are provided on an upper surface of the insulating substrate. The current fuse according to any one of claims 1 to 3 , and the current fuse are mounted in a mounting region with an upper surface facing down, and each of the connected regions serves as a wiring conductor in the mounting region. An electronic device with an external circuit connected to each.

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