JPH11185596A - Fuse - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fuse capable of ensurly cutting off under a high voltage. SOLUTION: A boxed container 4 with an opening 3 open on the lower face and a plate cover 5 to block the opening are formed of an insulating synthetic resin. A pair of metal terminals 11 are insert-molded on the cover 5. A metal wire 12 to be fused with an overcurrent is passed through an insulating nearly hollow column cylinder 14 which is provided with through-holes 18 on both end faces and filled with silica sand 15. The metal wire 12 guided out of the cylinder 14 is connected at both ends to metal terminals 11 and tensed. Organopolysiloxane-based polymer is applied to the metal terminals 11, ranging from the outer periphery of the metal wire 12 to both end faces of the cylinder 14, and a flexible ceramic sheet 20 is secured thereto. The organopolysiloxane- based polymer is hardened to form a coating 19 and the cover 5 and the container 4 are fitted to each other to form a fuse 1. The short-circuit of the metal wire 12 after fused is prevented by the arc-extinguishing operation of the silica sand 15 and the occurrence of arc due to metallic gas leaked from the cylinder 14 is prevented by the cooling operation of the ceramic sheet 20.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuse that protects against overcurrent by melting and opening metal.

[0002]

2. Description of the Related Art Conventionally, as a fuse of this type, for example, a configuration described in Japanese Patent Application Laid-Open No. 9-223451 is known.

In the fuse described in Japanese Patent Application Laid-Open No. 9-223451, a pair of metal terminals is provided on a lid which is attached by closing an opening on one surface of a container, and a metal wire is bridged between the metal terminals. ing. The metal wire and the connection portion of the metal wire and the metal terminal are coated with an organopolysiloxane polymer having an arc-extinguishing function so as to interpose a gap with the inner peripheral surface of the container.

On the other hand, silica sand is known as a substance having an excellent arc-extinguishing function.

[0005]

However, in the conventional fuse described in Japanese Patent Application Laid-Open No. 9-223451, when an overcurrent flows through a metal wire and the metal wire melts to generate a metal gas, an overcurrent occurs. When the current is high and the pressure of the metal gas is increased, the metal gas flows along the space between the metal terminal and the organopolysiloxane-based polymer, and the organopolysiloxane-based polymer may be separated from the metal terminal so as to blow off. For this reason, there is no substance that shields between the pair of metal terminals, and there is a possibility that an arc generated by fusing of the metal wire causes a short circuit between the metal terminals, which may cause damage such as melting of the metal terminals.

On the other hand, when the organopolysiloxane-based polymer is filled in the container without interposing a gap with the inner peripheral surface of the container so that the organopolysiloxane-based polymer is not blown off, the metal wire is cross-linked. The assembly of the cover provided with the metal terminals and the container becomes complicated, and the container may be damaged by the metal gas so that the container is blown off together with the organopolysiloxane polymer.

Further, when silica sand is used instead of the organopolysiloxane polymer, since the silica sand has a very high thermal conductivity, the temperature of the container becomes extremely high due to the heat generated by the metal wire during energization and fusing. And the container may be melted.

The present invention has been made in view of the above problems, and has as its object to provide a fuse which can be reliably cut off even under a high voltage and which can be easily manufactured.

[0009]

According to a first aspect of the present invention, there is provided a fuse, comprising: a pair of metal terminals; a metal wire stretched between the metal terminals and blown at a predetermined current value; An arc-extinguishing portion having an insulating hollow portion that accommodates the metal wire in the quartz sand while penetrating the metal wire, and a covering portion that covers the metal terminal with an organopolysiloxane polymer. A cooling member which is attached to the surface of the covering portion and has a flexibility mainly composed of ceramics.

[0010] An arc extinguishing portion is formed by penetrating a metal wire that blows at a predetermined current value or more through an insulating hollow portion for accommodating the silica sand so that it cannot escape, and accommodating the silica wire in the silica sand. Since the metal wire provided with is stretched between the pair of metal terminals, even if an overcurrent flows through the metal wire and the metal wire is blown out, the arc is extinguished by the silica sand and short circuit does not occur again. Also, even if the metal gas generated at the time of fusing the metal wire is released from the hollow portion, the cooling action of the flexible cooling member mainly composed of ceramics prevents the occurrence of the arc or shortens the duration of the arc. And prevent influence on the surroundings. Further, the flexibility of the cooling member facilitates the attachment to the metal terminal and improves the productivity, and the addition of the flexibility allows the organopolysiloxane-based polymer even when the cooling member is in a state where the metal gas can flow. Since the metal terminals are protected by the covering portions provided by covering the metal terminals, even if an arc is generated by the metal gas, the metal terminals are not short-circuited.

According to a second aspect of the present invention, there is provided the fuse according to the first aspect, further comprising a hollow box-shaped envelope for housing the metal wire and the arc-extinguishing portion therein.

Further, since the hollow box-shaped envelope accommodating the metal wire and the arc extinguishing portion is provided, the metal gas generated when the metal wire is blown is discharged from the arc extinguishing portion into the envelope. Therefore, the metal gas is not scattered to the outside, and damage to members located around the metal gas is prevented.

[0013]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a fuse according to an embodiment of the present invention.

1 and 2, reference numeral 1 denotes a fuse. The fuse 1 has an envelope 2. The envelope 2 includes a container 4 which is formed in a box shape with an opening 3 formed on the lower surface of, for example, polyether sulfone or polybutylene terephthalate having an insulating property, and an opening of the container 4. And a cover 5 which is formed in a plate shape with, for example, insulating polyethylene terephthalate or polybutylene terephthalate. The lid 5 has the same area as the opening area of the opening 3 of the container 4.

An engagement recess 7 as an engagement means is provided on the inner surface near the opening 3 of the container 4 at an opposing position. Further, on the outer peripheral surface of the lid 5, an outwardly protruding locking claw portion 8 as locking means for locking to the engaging concave portion 7 corresponding to the engaging concave portion 7 of the container 4 is provided. The locking means 9 is configured by the engagement of the engagement concave portion 7 and the locking claw portion 8 with each other, and the housing 4 and the lid 5 are integrally combined to configure the envelope 2. It should be noted that any structure that can be locked by engaging with each other, such as protruding into a claw shape as an engaging means and being formed into a concave shape as a locking means, can be used.

The lid 5 is provided with a pair of metal terminals 11, 11 which penetrate in the thickness direction and are formed, for example, of copper (Cu) in a thin line shape. Note that these metal terminals
In the surfaces of 11, 11, a low-melting metal (not shown) such as solder is coated on the surface by plating or the like. The metal terminals 11 are buried at the time of molding the lid 5 so that one end side protrudes longer than the other end side.

Further, a metal wire 12 that is blown at a current value of a predetermined value or more is stretched on one end side of the metal terminals 11 and 11 so that tension is not applied. The metal wire 12 has a lower melting point and is softer than the metal terminal 11, and has a higher melting point than the low melting point metal coated on the surfaces of the metal terminals 11, 11, for example, a low melting point alloy mainly composed of silver (Ag). Are formed in a thin line shape.

The metal wire 12 is provided with an arc extinguishing portion 13. The arc-extinguishing portion 13 has an approximately cylindrical cylindrical body 14 as an insulating hollow hollow portion through which the metal wire 12 penetrates, and an arc-extinguishing material filled in the cylindrical body 14 so as to cover the metal wire 12. It is composed of silica sand 15 as a material. The cylindrical body 14 has a substantially bottomed cylindrical body 16 having one end closed, and the body
It is formed in a substantially hollow cylindrical shape with both ends closed, with a closing plate 17 attached by closing the other end of 16. In addition, in the bottom 16a of the body 16 and in the approximate center of the closing plate 17, a through hole having a size through which the metal wire 12 can be inserted and in which the filled silica sand 15 cannot flow out when the metal wire 12 is inserted is provided. 18 and 18 are respectively drilled at opposing positions.

A coating portion 19 made of an organopolysiloxane polymer such as silicon resin or silicon rubber, which is a so-called silicon resin, is provided on the outer peripheral surface of the metal terminals 11, 11 on which the metal wire 12 is stretched. The coating is formed. The covering portion 19 is formed of a metal wire derived from the end face of the cylindrical body 14 and the cylindrical body 14.
The outer peripheral surface of 12 is also formed so as to cover the through hole 18 of the cylindrical body 14.

A ceramic sheet 20, which is a flexible cooling member mainly composed of ceramics, is attached to the outer peripheral surface of the covering portion 19 so as not to interfere with the cylindrical body 14 and the metal wire 12. I have.

Next, a method of manufacturing the fuse 1 will be described.

First, the container 4 and the lid 5 are formed of an insulating synthetic resin such as polybutylene terephthalate in advance. When the lid 5 is formed, a pair of metal terminals 11, 11 are arranged substantially in parallel and insert-molded. Further, the metal terminals 11 and 11 are subjected to a surface treatment by previously forming a low-melting metal such as solder (not shown) on the surface.

On the other hand, an arc extinguishing section 13 is formed by filling a silica body 15 serving as an arc extinguishing material into a body section 16 previously formed of an insulating member and attaching a closing plate 17 to form a cylindrical body 14. Next, while rotating the arc extinguishing section 13 around the central axis as a rotation axis,
For example, a thin metal wire 12 made of a low melting point alloy containing silver (Ag) as a main component is inserted through a hole 18 to penetrate the arc extinguishing portion 13.

Thereafter, both ends of the metal wire 12 to which the cylindrical body 14 is attached, which are led out from the cylindrical body 14, are connected to a pair of metal terminals 11 and Connect to one end of 11 and stretch. The connection of the metal wire 12 can be performed by any method such as spot welding, or by connecting the end of the metal terminal 11 by pressing and heating the metal terminal 11 so as to sandwich the metal wire.

Next, one end of the metal terminals 11, 11 where the metal wire 12 is stretched, the metal wire 12 led out from the cylinder 14, and both end faces of the cylinder 14 are treated with an organopolysiloxane polymer. Is applied, and the ceramic sheet 20 is attached to the organopolysiloxane-based polymer. Then, the organopolysiloxane-based polymer is cured by, for example, heating and drying to form the covering portion 19, and the ceramic sheet 20 is fixed. Note that the ceramic sheet 20 is porous in order to have flexibility, but a part of the organopolysiloxane polymer forming the coating portion 19 may have irregularities on the surface of the ceramic sheet 20 and pores. And enters the surface of the ceramic sheet 20 slightly.

Thereafter, the engaging recess 7 of the housing 4 and the locking claw 8 of the lid 5 are locked to cover the metal terminals 11, 11 on which the metal wire 12 provided with the cylindrical body 14 is stretched. The fuse 1 is formed by fitting the lid 5 and the housing 4 as described above.

Next, the operation of the fuse 1 will be described.

When an overcurrent flows through the metal terminals 11, 11 of the fuse 1 attached to a circuit board (not shown) for protection from overcurrent, the metal wire 12 is blown. The silica sand 15 is located at the fusing portion of the metal wire 12, and the arc is prevented by the arc-extinguishing effect of the silica sand 15 in the cylindrical body 14. Also metal wire
At the time of melting of 12, metal gas is generated. When the gas pressure of the metal gas increases, the metal gas passes through the through-hole of the cylindrical body 14.
From 18, it flows into the container 4 through the outer peripheral surface of the cylindrical body 14 and between the coating portions 19 formed of the organopolysiloxane polymer to be coated.

Here, the metal terminals 11, 11 are covered with the covering portion 19, and no arc due to the metal gas is generated by the cooling action of the ceramic sheet 20 attached to the metal terminals 11, 11, or the generated arc. Can be shortened, and the metal terminals 11, 11 covered by the covering portion 19 are not short-circuited by the arc, and the envelope 2 can be prevented from being damaged by the arc.

The ceramic sheet 20 is provided with flexibility such as a so-called ceramic paper.
Although it is porous and has air permeability, it is attached to the metal terminal 11 with the organopolysiloxane polymer forming the covering portion 19, so that the pores are closed and attached.

As described above, according to the above-described embodiment, the metal wire 12 penetrates the cylindrical body 14 of the arc-extinguishing portion 13 which is insulative and substantially cylindrical and accommodates the silica sand 15 so as not to flow out. Since the metal wire 12 is stretched between the pair of metal terminals 11 provided so that one end is located in the envelope 2, even if an overcurrent flows under a high voltage in the metal wire 12, the metal wire 12 is blown. Short-circuiting can be prevented without arcs being extinguished by silica sand and no arcing.

Further, even if the metal gas generated when the metal wire 12 is blown is released from the cylindrical body 14 into the envelope 2, the metal gas is covered by the coating portion 19 formed of the organopolysiloxane polymer. The short circuit is not caused by the arc generated by the metal gas flowing out between the metal terminals 11, and the generation of the arc can be prevented or the duration of the arc can be reduced by the cooling action of the ceramic sheet 20, and the envelope 2 can be prevented from being damaged. Furthermore, since the metal gas is released into the envelope 2 and is not scattered outside the fuse 1, it is possible to prevent an influence such as damaging surrounding members or short-circuiting a circuit pattern of a circuit board.

Since the ceramic sheet 20 has flexibility, the ceramic sheet 20 can be easily attached to the metal terminals 11 and 11 to improve the manufacturability. Even in the porous state having the permeable property, the insulation between the metal terminals 11 and 11 is not broken through the air-permeable ceramic sheet 20 because the insulation is attached at the covering portion 19. Even if an arc is generated by the metal gas between the metal terminals 11 and 11 covered with 19, a short circuit does not occur and the metal terminal can be reliably shut off.

Further, the generated metal gas is discharged from the arc extinguishing section 13 to the space inside the container 4, so that the metal gas pressure is relaxed in this space and the container 4 is blown off by the metal gas pressure. Damage of the envelope 2 can be prevented.

Then, the arc-extinguishing portion 13 formed by accommodating the silica sand 15 in the cylindrical body 14 is rotated around the central axis as the rotation axis, penetrates the metal wire 12 along the axial direction, and is accommodated in the silica sand 15. Metal wire
Since the arc extinguishing part 13 is provided on the metal sand 12, the silica sand 15 can be provided so as to easily cover the metal wire 12, and the productivity can be improved.

In the above embodiment, the surfaces of the metal terminals 11 and 11 are coated with a low-melting-point metal and surface-treated, but any of the metal terminals 11 and 11 and the metal wire 12 can be used.

The envelope 2 can be of any shape other than the configuration assembled by the locking means 9, and if there is no influence on the surroundings, the envelope 2 need not be used.

Furthermore, the hollow portion constituting the arc-extinguishing portion 13 has been described using the substantially cylindrical cylindrical body 14. However, the hollow portion that can accommodate the quartz sand 15 and penetrate through the metal wire 12 and be accommodated in the quartz sand 15 is described. Any shape can be used.

[0039]

Next, an experiment on the breaking characteristics of a fuse manufactured based on the embodiment of the above embodiment will be described.

The envelope 2 was made of glass reinforced polybutylene terephthalate resin (trade name: G2830R, manufactured by Mitsubishi Rayon Co., Ltd.). As the metal terminal 11, a copper wire having a diameter of 0.6 mm and having a surface plated with solder so as to have a thickness of about 12 μm was used. As the metal wire 12, a silver alloy wire having a diameter of 0.15 mm (a silver alloy of JIS-Z-3261) was used. In addition, the arc extinguishing part
In 13, the cylinder 14 was formed of a phenol resin, and silica sand (particle size: 42 to 48 mesh) was used as an arc-extinguishing material. Further, as the ceramic sheet 20, ceramic paper having a thickness of about 1 mm (trade name: Kao Wool Paper T, manufactured by Isolite Industry Co., Ltd.) is used. Pasted with something.

As a comparative sample, a comparative sample 1 in which a metal wire 12 is stretched by loosening a substantially middle portion between the metal terminals 11 and 11, and a metal wire 12 having an arc extinguishing portion 13 are connected to the metal terminals 11 and 11. Comparative sample 2 which was not provided with the covering portion 19 and the ceramic sheet 20 formed of the organopolysiloxane-based polymer only by being stretched in between, the ceramic sheet was not provided with the covering portion 19, and the ceramic sheet was positioned on the inner peripheral surface of the container 4. The comparative sample 3 was formed so as to be inserted and fixed so as to be fitted to cover the metal terminal 11.

Then, it is mounted on a printed circuit board (specified by IEC 127-4) by soldering, and 250
V, 500 A AC with a power factor (PF) of 0.
8 and a blocking test was performed, and the blocking state of each sample was observed.

As a result, in the comparative sample 1 in which the metal wire 12 is simply stretched and the comparative sample 2 in which only the arc extinguishing section 13 is provided, the metal terminals 11, 11 are melted without breaking the arc, and the printed circuit board is damaged. did. In Comparative Sample 3, in which the ceramic sheet 20 was provided without the covering portion 19, no damage was found on the printed circuit board, but the metal terminals 11, 11 were melted without breaking the arc. In the case of this example, no abnormal appearance was recognized, and the blocking was successfully completed.

[0044]

According to the fuse of the first aspect, the metal wire penetrates the hollow portion of the insulating arc-extinguishing portion for accommodating the silica sand so as not to flow out, and is accommodated in the silica sand so as to be interposed between the pair of metal terminals. Therefore, even if an overcurrent flows through the metal wire and the metal wire is blown out, no arc is generated due to the arc-extinguishing effect of the silica sand, thereby preventing a short circuit. Also,
Even if the metal gas generated at the time of fusing the metal wire is released from the hollow part, the cooling action of the flexible cooling member mainly composed of ceramics can prevent the occurrence of an arc or shorten the duration of the arc, The influence on the surroundings can be prevented. Furthermore, the flexibility of the cooling member can be easily attached to the metal terminal to improve the manufacturability, and the flexibility imparts the organopolysiloxane-based polymer to the organopolysiloxane polymer even when the cooling member is in a state where the metal gas can flow. In a state where the metal terminal is protected by the coating portion formed by coating the metal terminal, even if an arc is generated by the metal gas, a short circuit between the metal terminals can be prevented.

According to the fuse of the second aspect, in addition to the effect of the fuse of the first aspect, since the metal box and the hollow box-shaped envelope accommodating the arc-extinguishing portion are provided, the metal wire is blown. Since the metal gas generated at this time is discharged from the arc extinguishing portion into the envelope, the metal gas does not scatter outside and damage to members located around the metal gas can be prevented.

[Brief description of the drawings]

FIG. 1 is a side sectional view of a fuse showing an embodiment of the present invention.

FIG. 2 is a plan sectional view of the same.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Fuse 2 Enclosure 11 Metal terminal 12 Metal wire 13 Arc extinguishing part 14 Cylindrical body as hollow part 15 Silica sand 19 Coating part 20 Ceramic sheet which is a cooling member

Claims (2)

[Claims] 1. A pair of metal terminals, a metal wire stretched between these metal terminals and blown at a predetermined current value or more; An arc-extinguishing portion having an insulating hollow portion accommodated in the quartz sand; a coating portion covering the metal terminal with an organopolysiloxane polymer; and a ceramic as a main component attached to the surface of the coating portion. A fuse, comprising: a cooling member having flexibility. 2. The fuse according to claim 1, further comprising a hollow box-shaped envelope that accommodates the metal wire and the arc-extinguishing section therein.