JPH07201263A - Thin type fuse - Google Patents

Abstract

PURPOSE:To provide such a thin type fuse as being capable of well preventing the breakage of a low melting point fusible metal strip in a simple means even if bending or torsional moment is applied to band conductors by providing a specified groove in the surface of an insulating layer. CONSTITUTION:The ends 21 of a pair of band conductors 2, 2 are put in contact with the back of an insulating plate 1, the swollen portions 22 formed at near the centers of these ends 21 are exposed to the surface of the insulating plate 1 and the contact faces of the insulating plate 1 with the band conductors 2 are welded. A low melting point fusible metal strip 3 is bridged between the exposed portions 22, 22 of the band conductors with welding or brazing and an insulating layer 5 is applied on the surface of the insulating plate 1. A longitudinal groove 51 is provided as an improving means in the surface of the insulating layer 5 along its four-way edges.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to thin fuses, for example,
The present invention relates to an alloy type thin temperature fuse.

[0002]

2. Description of the Related Art In an alloy type temperature fuse, it is used by being attached to an electric device to be protected, and when the electric device generates heat due to an overcurrent, the generated heat is melted by a low melting point which is a fuse element. It is transmitted to the metal piece, the low melting point metal piece is melted and the electric power to the electric equipment is cut off,
It is possible to prevent abnormal heat generation of the electric device and eventually a fire.

In this alloy type temperature fuse, a flux having a melting point lower than that of the metal piece is applied onto the low melting point fusible metal piece, and the molten low melting point fusible metal is already melted. Under the coexistence with, the spheroidization is caused by the interfacial energy, the molten metal is divided by the progress of the spheroidization, and when the arc generated during this division disappears due to the increase in the distance between the divisions, the current is cut off. The above-mentioned interruption of energization is completed, and the divided molten metal is cooled and solidified as the electric equipment is cooled.

With the recent miniaturization of electrical equipment, the fuses are also required to be smaller and thinner. However,
In the present inventor, each end portion of the pair of strip-shaped conductors is brought into contact with the back surface of the insulating plate, and the substantially central portion of each end portion is exposed on the surface of the insulating plate and the insulating plate. It has already been proposed a thin fuse in which a low melting point fusible metal piece is bridged between the exposed portions of the strip-shaped conductor by bonding between the strip-shaped conductor and the strip-shaped conductor, and an insulating layer is coated on the surface side of the insulating plate. .

In this thin fuse, an insulating plate is used.
It is not necessary to pull out a lead conductor from between the
It is possible to easily prevent the outflow of molten metal and molten flux during fuse operation, and to efficiently transfer the heat generated by the equipment to the low melting point fusible metal piece through the band-shaped conductor, resulting in quick operation characteristics. Can be guaranteed.

[0006]

However, in this thin fuse, the bending or torsional rigidity of the low melting point fusible metal piece is smaller than that of the strip conductor, and the insulating plate and insulating layer are smaller than those of the strip conductor. When the bending moment or the twisting moment acts on the belt-shaped conductor, the portion between the pair of belt-shaped conductors is intensively bent or twisted and deformed to have a low melting point. The soluble metal pieces are easily broken.

It is an object of the present invention to bring the ends of a pair of strip-shaped conductors into contact with the back surface of the insulating plate so that the substantially central portion of each end is exposed on the surface of the insulating plate. A thin fuse in which a plate and a band-shaped conductor are bonded to each other, a low melting point fusible metal piece is bridged between the exposed parts of the band-shaped conductor, and an insulating layer is coated on the surface of the insulating plate. In order to provide a thin fuse capable of satisfactorily preventing the low melting point fusible metal piece from being broken by a simple means even when a bending or twisting moment acts on the strip conductor.

[0008]

A thin fuse according to the present invention
The ends of the pair of strip-shaped conductors are brought into contact with the back surface of the insulating plate so that the substantially central portions of these end portions are exposed on the surface of the insulating plate, and the insulating plate and the strip-shaped conductor are exposed. In the fuse in which the low melting point metal piece is bridged between the exposed portions of the strip-shaped conductor, and the surface side of the insulating plate is covered with the insulating layer, the surface of the insulating layer is insulated. A longitudinal groove along the edge of the layer or a thick portion is provided.

[0009]

By providing a groove in the longitudinal direction along the edge of the insulating layer on the surface of the insulating layer, the bending or twisting rigidity of the portion on the side where the low melting point fusible metal piece is present is defined by the groove. Direction of the insulating layer extending in the direction) is larger than the bending or twisting rigidity, and even if bending or twisting moment acts on the band-shaped conductor, the other side part of which the bending or twisting rigidity is small is bent or twisted. A portion that is bent or twisted and deformed to a greater extent than a portion having a large torsional rigidity (a portion where the low melting point soluble metal piece exists), that is, a portion having a large bending or torsional rigidity, that is, the side where the low melting point soluble metal piece exists Since the bending or twisting deformation of the portion is small, the breakage of the low melting point fusible metal piece is well prevented.

Further, when a thick portion in the longitudinal direction along the edge of the insulating layer is provided on the surface of the insulating layer, the thick portion has a rib action against bending or twisting and bends or twists in the strip conductor. When the ment acts, the amount of bending or twisting deformation of the portion where the low melting point soluble metal piece is present between the pair of strip-shaped conductors is suppressed due to the rib action. Is well prevented from breaking.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. 1A is a perspective explanatory view showing an embodiment of the invention described in claim 1, FIG. 1B is a plan explanatory view thereof, FIG. 1C is a bottom explanatory view thereof, and FIG. (D) is a sectional view taken along line (ii) in FIG. In FIGS. 1A to 1D, 1 is an insulating plate.
Reference numerals 2 and 2 are a pair of strip-shaped conductors, each conductor end portion 21 being in contact with the back surface of the insulating plate 1, and a bulging portion 22 formed substantially in the center of the contact end portion 21 being in the insulating plate 1. And the contact surface between the insulating plate 1 and the strip-shaped conductor 2 is adhered. Reference numeral 3 denotes a low melting point fusible metal piece bridged by welding or brazing between the strip-shaped conductor exposed portions 22, 22 and 4 denotes a flux applied to the low melting point fusible metal piece. Reference numeral 5 is an insulating layer coated on the surface side of the insulating plate, and 51 is a groove provided on the surface of the insulating layer along the four edges of the insulating layer.

The above-mentioned insulating plate 1 and insulating coating layer 5
For the thermoplastic resin, for example, polyethylene, vinyl chloride, polypropylene, polystyrene, ethylene-propylene, polyimide, polyethylene terephthalate, etc. can be used, and the same material is used for the insulating plate and the insulating coating layer. It is preferable to use one made of different materials, but it is also possible to use one made of different materials.

The strip-shaped conductor 2 is made of a single body of copper, or, as shown in FIG. 2, the surface of the insulating plate contacting the back surface is copper 201 and the other portion 202 is made of a different metal. It is also possible to use a composite with nickel, for example.

In order to bond the end portion of the strip-shaped conductor to the insulating plate, a swelling portion is pressed on the end portion of the strip-shaped conductor, and a hole slightly smaller than the swelling portion is formed in the insulating plate. Then, the end of the strip-shaped conductor is brought into contact with the back surface of the insulating plate, the bulging portion of the end of the strip-shaped conductor is fitted into the hole of the insulating plate, and the contact surfaces of both are pressed and heat-sealed together. The bulging part is pressed to the part, the end of the strip-shaped conductor is brought into contact with the back surface of the insulating plate,
Press and press under heating to cause the bulging part to bite toward the surface of the insulating plate and heat-bond the insulating plate and the band-shaped conductor, and remove the resin on the bulging part by grinding to swell A method of exposing the parts can be used.

After covering the insulating layer 5 with a low melting point fusible metal piece, a thermoplastic film 5 is placed on the upper side of the insulating plate 1 as shown in FIG. A cooling cylinder 61 is brought into contact with the central portion of the upper surface of the film 5, and the low melting point metal piece is cooled by the circulation of the cryogen 62 to the cylinder 61, while the insulating plate 5 is surrounded by an insulating plate by a heating ring 63. It is possible to use a method of heat-sealing the periphery of 1 and press-forming the four-way groove.

In the above embodiment, because of the longitudinal groove in the groove along the four-sided edge, the portion on the side where the low melting point metal piece is present [a in FIG. 1 (a)] is the boundary of this groove. The bending or twisting rigidity of the side part) becomes greater than the bending or twisting rigidity of the other side part (the b side part of (a) in FIG. 1) (mainly due to the size of the width), and bends or twists in the band-shaped conductor 2. When the moment acts, the other side portion b having a small bending or torsional rigidity is bent or twisted more largely than the portion a on the side where the low-melting point fusible metal piece having a large bending or torsional rigidity is present. Alternatively, since the bending or twisting deformation of the portion a on the side where the low melting point fusible metal piece having high torsional rigidity is present is small, the breakage of the low melting point fusible metal piece can be well prevented.

In the above embodiment, the grooves are provided along the four edges of the insulating layer, but it is also possible to provide only the longitudinal groove at the width end of the insulating layer.

FIG. 4 is a perspective explanatory view showing an embodiment of the invention described in claim 2, in which the above-mentioned groove is formed on the surface of the insulating layer 1.
The thick portion 52 is provided, and the other structure is substantially the same as that of the embodiment of claim 1.

In this embodiment, the thick-walled portion 52 exhibits a rib action against bending or twisting, and when the bending or twisting moment acts on the strip-shaped conductor, a low melting point between the pair of strip-shaped conductors is possible. Since the amount of bending or twisting deformation of the portion where the molten metal piece is present is suppressed due to the rib action, the breakage of the low melting point soluble metal piece can be well prevented. In addition,
In this embodiment, the thick portion is provided along the four edges of the insulating layer, but it is also possible to provide only the thick portion in the longitudinal direction at the width end of the insulating layer.

[0020]

According to the present invention, the ends of the pair of strip-shaped conductors are brought into contact with the back surface of the insulating plate so that the substantially central portions of these ends are exposed on the surface of the insulating plate and insulated. In a fuse in which a plate and a band-shaped conductor are bonded to each other, a low melting point fusible metal piece is bridged between the exposed parts of the band-shaped conductor, and an insulating layer is coated on the surface of the insulating plate. By only providing a groove or thick portion on the surface of the insulating layer, it is possible to prevent breakage of the low melting point fusible metal piece under the action of bending or twisting moments. This can be easily carried out only by processing a molding surface for forming a groove or forming a thick portion in a pressure die.

In the fuse of the present invention, when the melting point of the low melting point soluble metal piece reaches its melting point T, that is, the temperature rise due to the Jule heat generation of the low melting point soluble metal piece is Δt ₁ , the equipment generation. The temperature rise of the low melting point fusible metal piece due to the receipt of heat Δ
If t ₂ and the ambient temperature are t ₀ , then t ₀ + Δt ₁ + Δt ₂ = T
When the current is large and the energizing current is large, Δt ₁ becomes large, and the fuse operates when Δt ₂ is relatively small. In this case, the energizing current is large and the arc energy is large. -As a result of the increase, the internal pressure generated due to the arc becomes particularly high, but even in such a case, the thermoplastic film for the insulating plate and the insulating coating, especially the thermoplastic film for the insulating coating is excellent. Due to its flexibility (expansion), it can absorb the internal pressure well and can avoid the explosion of the fuse to ensure the safety.

[Brief description of drawings]

1 (a) is a perspective explanatory view showing an embodiment of the invention of claim 1, FIG. 1 (b) is a similar plan explanatory view, FIG. 1 (c) is a similar bottom explanatory view, FIG. 1 (d) is a cross-sectional view taken along line 2-2 in FIG. 1 (b).

FIG. 2 is a perspective view showing an example of a strip-shaped conductor used in the present invention.

FIG. 3 is an explanatory view showing a pressing device used for manufacturing the thin fuse of the present invention.

FIG. 4 is an explanatory perspective view showing an embodiment of the invention of claim 2;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Insulation plate 2 Band-shaped conductor 21 Band-shaped conductor end 22 Exposed part of the band-shaped conductor 3 Low melting point fusible metal piece 5 Insulating layer 51 Groove 52 Thick part

Claims (2)

[Claims] 1. An end face of a pair of strip-shaped conductors is brought into contact with the back surface of an insulating plate, and a substantially central part of each end part is exposed on the surface of the insulating plate. In a fuse in which a band-shaped conductor is adhered, a low melting point fusible metal piece is bridged between the exposed parts of the band-shaped conductor, and the surface side of the insulating plate is covered with an insulating layer, the surface of the insulating layer is A thin fuse characterized in that a longitudinal groove is provided along the edge of the insulating layer.
Z. 2. An end face of a pair of strip-shaped conductors is brought into contact with the back surface of the insulating plate so that the substantially central portion of each end is exposed on the surface of the insulating plate and the insulating plate. In a fuse in which a band-shaped conductor is adhered, a low melting point fusible metal piece is bridged between the exposed parts of the band-shaped conductor, and the surface side of the insulating plate is covered with an insulating layer, the surface of the insulating layer is A thin fuse characterized in that a thick portion is provided along the edge of the insulating layer.