JPH025327A - Fuse - Google Patents

Abstract

PURPOSE:To have usability for general purpose, possibility for miniaturization and easiness for handling by having a current path of fuse material, which is provided on the inner wall face of a body facing the space part, and whose ends are connected to each of electrodes respectively. CONSTITUTION:A body 10 has a cylindrical form with a penetrating hole to form a space part 12 in its center. A current path 14 is formed spirally on the inner wall face of the body 10 facing the space part 12 from one end of the body 10 to another. This current path 14 is formed in such a way that after fuse material of tin, lead alloy or others is attached thin-filmlike on the inner wall face of the body 10 facing the space part 12 beforehand by vapor deposition, printing, or plating, the surface of the fuse material is cutting- processed until the depth reaching to the inner wall face of the body 10 by use of a cutting tool or a laser cutter. In this cutting processing, spiral cutting is performed so as to form a strip of the current path 14 connecting both end parts of the inner wall where the fuse material remains left.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to fuses.

(Prior Art) Conventionally, a fuse is inserted into a circuit to protect the circuit when an overcurrent flows. Examples of such fuses are shown in FIGS. 4 to 6.

The fuse shown in FIG. 4 has claw-like electrodes 102 and 104 provided at both ends of a fuse material 100, and is used for boat fishing by being attached to a switch of a power receiving facility.

The fuse shown in FIG.
Fit and fix the metal cap 12.114, insert the fuse wire 116 into the glass tube 110 through the small hole provided in the electrode 112.114, and solder both ends of the fuse wire 116 to the electrode 112.114. It is attached. Furthermore, external leads 118,120 are also soldered to the electrodes 112,114. Fuses of this type without external leads are also known.

The fuse shown in FIG.
36 is connected, the opening 138 of the casing 130 is closed with a lid 140, and both ends of the casing 130 are sealed with resin or the like, and external leads 132 and 134 are fixed.

(Problems to be Solved by the Invention) However, the above conventional fuses have the following problems.

Fuses with claws for switches are large and have the problem of being difficult to use for applications other than switches due to their shape. It is particularly unsuitable for mounting on circuit boards. For fuses in which the fuse wire is attached to a glass tube or a casing made of insulating material, a certain distance is required between the electrodes or leads because the fuse wire is stretched inside the glass tube or casing, making it possible to reduce the size of the fuse. do not have.

Furthermore, since they are easily broken, they often break, making them troublesome to handle, and also making it difficult to automatically attach the fuse to the board.

Therefore, the present invention has versatility and can be miniaturized.
The purpose is to provide fuses that are easy to handle.

(Means for Solving the Problems) In order to solve the above problems, the present invention has the following configuration: A base made of an electrically insulating solid material and formed into a cylindrical shape having a hollow space. a part, two electrodes made of a conductive material and fixed to the base part at a predetermined interval, and a fuse material provided on the inner wall surface of the space part of the base part, and both ends of the electrodes are fixed to the base part at a predetermined distance. and a current path connected to each electrode.

(effect) Let's talk about the action.

When an overcurrent flows through the current path, the fuse material forming the current path on the inner wall surface of the space of the base body is heated and melted by the overcurrent, and the current path is cut off. This stops the current flow between both electrodes.

(Embodiments) Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[First example] A first embodiment will be described with reference to FIG.

Reference numeral 10 denotes a base portion, which has a cylindrical shape with a through hole bored in the center to form a space 12. Base part 1
0 is made of an electrically insulating solid material such as ceramic, glass, or plastic.

Reference numeral 14 denotes a current path, which is formed in a spiral shape on the inner wall surface of the space 12 provided in the base body 10 from one end of the base body 1O to the other end. This current path 14 is formed by applying tin, which is a fuse material, on the inner wall surface of the space 12 of the base body 10 in advance.
After depositing a lead alloy or the like in a thin film by vapor depositing, printing, or peeling, the surface of the fuse material is cut using a cutting tool or a laser cutter to a depth that reaches the inner wall surface of the base portion 10. It is formed. In the cutting process, fuse material is left at both ends of the inner wall of the space 12, and spiral cutting is performed to form a single current path 14 connecting the remaining ends.

Reference numerals 16 and 18 designate electrodes, which are formed on a metal cap made of a conductive material such as silver, and have protruding portions 20 and 22 provided to protrude inward, respectively, in the space 1 of the base portion 10.
It is fixed by fitting into both ends of 2.

For both electrodes 16 and 18, the outer surfaces of protrusions 20 and 22 are
Since it is electrically connected to the fuse material left at both ends on the inner wall surface of the space 12 of the base body 10, that is, both ends of the current path 14, a single spiral is formed between the electrodes 16 and 18. They are electrically connected by a continuous current path 14.

The fuse thus constructed can be used by fitting the electrodes 16, 18 into a socket provided on a circuit board or the like and fixing the fuse. The current path 14 is provided inside the base portion 10 formed of a solid material, has a sturdy structure, and is easy to handle.

Note that the fuse blowing current value is determined by the width W, thickness T, and length of the current path 14, so by adjusting the cutting width C of the spiral cutting, a conventional fuse wire can be stretched in a substantially straight line. In comparison, you can get quite a bit of length. Therefore, if the current path 14 has the same length as a conventional fuse wire, it is possible to significantly reduce the size.

In this embodiment, electrodes 16.1 are provided at both ends of the base portion 100.
Since the space 12 is closed by fixing the space 8, foreign matter is prevented from entering the space 12. However, if the electrodes 16 and 18 have a shape that does not close both ends of the space 12, the inner wall surface of the space 12, including the current path 14, may be protected by forming a protective film with silicone heat-resistant paint or resin. , a heat-resistant resin or the like is sealed in the space 12 to form the current path 14.
What is necessary is to prevent short circuits between the main body and other members.

The melting point of the protective film and the encapsulating member is preferably 600° C. or higher, and is set higher than the melting point of the fuse material forming the current path 14.

Furthermore, even if the space 12 is open, if the fuse is housed in a fuse case or the like, the current path 14
There is no need to provide a protective film or the like as there is no need to worry about contact with other parts.

[Second example] A second embodiment will be described with reference to FIG.

In this embodiment, the current path 30 is formed linearly.

In this case, since the length of the current path 30 is determined in advance, the fusing current value is adjusted by the width or thickness of the current path 30. Although only one current path 30 is shown, a plurality of current paths 30 may be provided, including in the case of the first embodiment.

Furthermore, in this embodiment, the external leads 3 are connected to the electrodes 32, 34.
6.38 is attached and formed discretely, and in some cases an external lead 3 is attached instead of the electrode 32.34.
6.38 may be connected to the current path 30 and attached to the base portion 10.

Of course, it is also possible to have a linear current path 30 with only electrodes 32, 34 and no external leads 36, 38.

In addition, if the external leads 36, 38 are provided and the fuse is made into a discrete type, it becomes possible to automatically attach the fuse onto the circuit board by a machine by taping the external leads 36, 38.

[Third example] A third embodiment will be described with reference to FIG.

In this embodiment, the outer shape of the base body 40 is formed into a rectangular parallelepiped similar to a semiconductor chip, and the base body 40 can be divided into an upper part 42 and a lower part 44. A current path (not shown) is formed in a space (not shown) between the upper part 42 and the lower part 44 . Various patterns for the current path can be considered, including straight lines and curved shapes including spirals, but if the inner wall surface of the space where the current path is provided is flat, it is possible to increase the distance with a meandering folded pattern. .

As in the second embodiment, the base portion 40 is provided with external leads 50.52 for the electrodes 46.48, but the electrodes 46.48 alone may be used, or instead of the electrodes 48.48, external leads 50.52 connected to the current path are provided. Only leads 50, 52 may be provided.

Forming the base portion 40 into a chip shape makes it suitable for automatic mounting onto a circuit board using a robot device, for example.

As another embodiment, although not shown, a fuse material forming a current path previously formed to have a predetermined length, width, and thickness may be attached on the inner wall surface of the space. The pattern of the current path at this time may be arbitrary, such as spiral, straight line, or folded back.

Further, for all the embodiments, it will be easier to use if the fusing current value and the like are displayed on the outer surface of the base portion using color lines or character symbols.

Various preferred embodiments of the present invention have been described above, but the present invention is not limited to the above-described embodiments. For example, the electrodes and external leads may not necessarily be fixed at the ends. Of course, many more modifications may be made without departing from the spirit of the invention.

(Effects of the Invention) When the fuse according to the present invention is used, a versatile fuse can be provided by forming the base portion into an arbitrary shape and size. Furthermore, since a solid material is used for the base, it is a sturdy fuse that is easy to handle, and there is no risk of wire breakage. By making the base portion into a chip shape and providing external leads, it is also possible to automatically attach the fuse to a circuit board or the like. Furthermore, since the width and thickness of the current path can be easily adjusted, the fusing current value can be set precisely.

[Brief explanation of the drawing]

FIG. 1 is a front sectional view showing a first embodiment of a fuse according to the present invention, FIG. 2 is a front sectional view showing a second embodiment, and FIG. 3 is a perspective view showing a third embodiment. 4 to 6 are drawings showing conventional fuses. DESCRIPTION OF SYMBOLS 10... Base part, 12... Space part, 14... Current path, 16.18... Electrode, 30... Current path,
32.34...electrode, 36.38...external lead, 40...base part, 46.48...electrode, 50.5
2 ・ ・ ・External lead.

Claims (1)

[Claims] 1. A base made of an electrically insulating solid material and formed into a cylindrical shape with a hollow space, and a base made of a conductive material with a predetermined interval between the base parts. A fuse comprising: two fixed electrodes; and a current path made of a fuse material and provided on the inner wall surface of the space of the base, both ends of which are connected to each of the electrodes. . 2. The fuse according to claim 1, wherein the electrodes are fixed to both ends of the base body and close the space. 3. The fuse according to claim 1 or 2, wherein an external lead is connected to the electrode. 4. The fuse according to claim 1 or 2, wherein an external lead is provided in place of the electrode.