JPH0434251B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a block-type fuse, and more specifically, to a block-type fuse adapted to obtain a fusing action at a temperature much lower than the red-hot temperature of the fusible part. This invention relates to an improvement of the block-type fuse.

[Conventional technology]

Conventional block type fuses of this type are disclosed in Japanese Patent Application Laid-open No. 163127/1982 and Japanese Utility Model Application No. 66844/1983.
There is a technique disclosed in Japanese Utility Model Application Publication No. 58-345.

First of all, the device disclosed in JP-A No. 58-163127 has a structure in which the fusible part and each terminal part are integrally formed using a copper alloy as a material, and the material is , Fe (iron) is 0.5-3.5%, P (phosphorus) is 0.01-0.15%, Zn (zinc) is 0.01-1.0%,
The remainder has a composition of Cu (copper). Of the same composition, Fe has an effect on improving the fusing property after red heat and against stress corrosion cracking, and also has an effect of increasing strength, and P similarly improves the fusing property after red heat. It is also described that Zn is effective in deoxidizing during melt cutting, and that it increases strength and acts effectively as a deoxidizing and degassing agent in the melting process during material production. Furthermore, in this product, the fusible body part that is integrally molded with each terminal part is sealed and fixed with a ceramic heat absorber, excluding the narrow part that will become a melting point, to absorb the heat generated by the fusible body part, and the casing The aim is to reduce the thermal effects on the surrounding areas.

Next, in the method disclosed in Japanese Utility Model Application No. 59-66844, a fusible conductor is formed from a metal with large thermal distortion such as a bimetal, and this is spot-welded to each terminal portion made of a copper alloy. By using the bimetal as a fusible conductor in a bonded structure, the fusing action can be sharply and reliably performed by the simultaneous action of fusing due to short circuit current and tensile stress due to thermal strain. In this case, since it cannot handle the starting current of the motor load, etc., a heat absorber made of a low melting point alloy is placed in the middle of the fusible conductor to absorb the heat generated by the fusible conductor. By delaying the time, there is a time lag for fusing in the large current range.

Furthermore, the device disclosed in Japanese Utility Model Application Publication No. 58-345 provides a fusing accelerator such as ceramic in the fusing part at the center of the fusible conductor to speed up the fusing time in a small current range and achieve so-called quick characteristics. I'm trying to make it last.

[Problem that the invention seeks to solve]

However, in each of the fuses according to the above-mentioned conventional examples, for example, the rated current is 150%
% overload current, it is not possible to fuse this without any problem. In other words, in general, the melting of a fusible conductor occurs only after the fused part becomes red-hot, that is, reaches a significantly high temperature. This may cause damage to the housing due to heat effects, or adversely affect other equipment or cables placed in the surrounding area, and furthermore, heat cycles due to intermittent currents near the rated current. It was relatively susceptible to deterioration.

This invention was made to solve the above-mentioned conventional problems, and its purpose is to lower the red-hot temperature of the fusible part by using an overload current of about 150% of the rated current! It is an object of the present invention to provide a block type fuse of this type which can obtain a fusing action at a very low temperature and which does not deteriorate due to heat cycles.

[Means for solving problems]

In order to achieve the above object, the block type fuse according to the present invention includes a horizontally extending fusible part,
and a pair of terminal parts extending perpendicularly downward from both ends of the fusible part, each of which is integrally molded from a copper alloy material, and a narrow terminal part is provided in the longitudinal middle part of the fusible part. a fused portion, and a pair of heat absorbing portions each having a concave shape in the longitudinal direction sandwiching the fused portion, and further,
A heat absorbing member made of a heat absorbing member made of tin or a tin alloy, a flux disposed on the longitudinal center portion or the outer circumferential surface thereof, and a heat absorbing body made of a conductive member surrounding and covering the longitudinal outer circumferential surface thereof is provided, and a concave portion of each heat absorbing portion is provided. A heat absorbing body is fitted and fixed inside each.

[Effect]

That is, in this invention, when the fuse is fused in a relatively small current range, that is, when a current of about twice the rated current flows through the fusible part, the heat generated in the fused part is transferred to the heat absorbing part, The flux is melted and activated, and when the temperature further rises and reaches the melting point of the endothermic member, the endothermic member begins to melt, and together with the activated flux, the copper alloy surface of the fusible body melts. Wetting begins, the tin component is diffused into this base material, causing local alloying, and the electrical resistance value of this alloyed part increases at an accelerated rate, accelerating the fusing time and reaching a predetermined temperature. The fusing action is quickly achieved at this point, and due to the diffusion and alloying of the tin component into the copper base metal, the melting temperature is lowered and red-hot formation is suppressed, and the fusing action is quickly achieved in the high current range. Even in the case of melting, the heat generated at the fusing part is transferred to the heat absorbing part, and this is used as the latent heat of melting to melt the tin. This also suppresses red heat at the fusing part, and as a result, surface oxidation is reduced. As a result, deterioration due to heat cycles can be effectively prevented.

〔Example〕

Hereinafter, one embodiment of the block type fuse according to the present invention will be described in detail with reference to FIGS. 1 to 4.

FIG. 1 is a perspective view showing the overall structure of a block type fuse to which an embodiment of the present invention is applied, FIG. FIG. 4 is a longitudinal cross-sectional view showing the line section in FIG. 1 of the same as above, and FIG. 4 is a cross-sectional view corresponding to FIG. 2 according to another embodiment of the same.

That is, in the embodiments shown in FIGS. 1 to 3, the block type fuse 1 includes a fusible body part 2 extending substantially horizontally, and a pair of terminal parts 3 extending vertically downward from both ends of the fusible body part 2. It consists of
These fusible parts 2 and each terminal part 3 are made of plate-shaped copper containing 0.1% Fe (iron), 0.03% P (phosphorus), and the balance 99.8% or more Cu (copper) by weight. An alloy material is used, and the copper alloy material is integrally formed by punching, bending, etc.

Thus, a narrow fusing portion 4 is formed in the longitudinally intermediate portion of the fusible body portion 2, and
A pair of heat absorbing parts 5 are formed on both sides of the fusing part 4, and the surfaces of these parts 2, 4, and 5 are tin-plated.
On the other hand, the heat absorbing body 6 is fixed by caulking and pressurization. In this case, tin plating is applied to the surfaces of the fusible part 2, the fusing part 4, and the heat absorbing part 5.
When a non-fusing current is applied, the copper alloy material that is the material is oxidized due to heat generation.
This is to prevent surface peeling that causes blackening and property deterioration.

Furthermore, in the case of the embodiment configurations shown in FIGS. 1 to 3, the heat absorbing portion 5 has a rectangular recessed section in its longitudinal direction, and the heat absorbing body 6 has a rectangular cross section. It is formed into a rectangular shape, and its lower half is fitted tightly into the rectangular concave heat absorbing portion 5, and its upper half protrudes upward. The reason why the heat absorbing part 5 is formed to have a concave shape in the longitudinal direction is to make it easier to hold the block-shaped heat absorbing body 6 in the heat absorbing part 5, thereby obtaining stable positioning of the heat absorbing body 6. ,
Another purpose is to further increase the heat generating area by increasing the energized area as much as possible.

Here, as shown in FIGS. 2 and 3, the heat absorbing body 6 may be a longitudinal center portion of a heat absorbing member 7 made of tin or a tin alloy, or a fourth heat absorbing member 7 as another embodiment. As shown in the figure,
Flux 8 is disposed on the outer circumferential surface in the longitudinal direction, and the outer circumferential surface in the longitudinal direction is further surrounded and covered with a conductive member 9 made of a copper alloy. When attached to the heat absorbing portion 5, the lower halves of both end surfaces of the heat absorbing member 7, flux 8, and conductive member 9 of the heat absorbing body 6 are in strong contact with the inner end surfaces of the rectangular concave portion of the heat absorbing portion 5. pressure and are combined to form a whole. The conductive member 9 surrounds and covers the outer peripheral surfaces of the heat absorbing member 7 and the flux 8 in the longitudinal direction.By increasing the enclosing area of the conductive member 9, accurate heat can be generated in a short time. This is to cause a reaction to occur in the internal heat absorbing member 7 and flux 8, and to enable the heat absorbing body 6 surrounded and covered with the conductive member 9 to be properly clamped by the heat absorbing portion 5 having the concave shape. be. Here, as the flux 8, resin, rosin, colphony, etc. can be used, and the heat absorbing member 7
Preferably, the content of Flux 8 is in the range of about 0.2 to 5% by weight, based on tin or tin alloy.

However, in the embodiment configurations shown in FIGS. 1 to 3 and the embodiment configuration shown in FIG. When the flux 8 flows, the heat generated in the narrow fusing part 4 is transferred to the heat absorbing part 5, and when the temperature of the heat absorbing body 6 reaches about 125°C, the flux 8 melts to about 174°C. When the temperature rises further and reaches the melting point temperature of the heat absorbing member 7, which is the melting point temperature of tin or tin alloy, approximately 232°C, the heat absorbing member 7 begins to melt and becomes activated. Together with the flux 8, the copper alloy surface of the fusible body part 2, which is the base metal, starts to wet, and in this base metal, especially the base metal part A that is in contact with the heat absorber 6 on the fusible body part 2 side. , the tin component is diffused and locally alloys the same portion A, and as the alloying further progresses as the temperature rises, the electrical resistance value of this alloyed portion increases at an accelerating rate, In addition to accelerating the melting time in the same part A, the temperature is approximately 600~600℃.
It melts immediately when it reaches 700℃.

On the other hand, at this time, if the base material is copper alone,
As the temperature rises, it becomes red hot and affects the casing or equipment around the fuse, causing undesirable results, but as mentioned above, tin is present in the copper base material. Because the components are diffused and alloyed, the melting temperature is lowered and a fusing action can be obtained without becoming red-hot, which reduces surface oxidation and effectively prevents deterioration due to heat cycles.

In addition, even in the case of melting in a large current range,
The heat generated at the narrow fusing section 4 is transferred to the heat absorbing section 5 and used as latent heat of melting to melt the tin, so red heat at the fusing section 4 is suppressed here as well.

Here, we will discuss the block-type fuse of the present invention according to the configuration of the above-mentioned embodiment and the conventional example disclosed in Japanese Patent Application Laid-open No. Sho.
The results of a performance comparison test with fuses disclosed in Japanese Utility Model Publication No. 58-163127 and Japanese Utility Model Application Publication No. 59-66844 will be described.

The performance comparison tests conducted included a voltage drop test, a fusing test, a temperature rise test, an intermittent current durability test, and a vibration durability test.

In the voltage drop test, the example product of the present invention showed a lower value of about 48 to 51% when compared to the conventional product.

In the fusing test, in the conventional product, the fusible part became red hot during fusing, and the terminal part became high temperature, but the example product of the present invention was fused without becoming red hot, and the temperature of the terminal part was also higher than that of the conventional product. When compared to the above, the value was significantly lower, and there was no abnormality caused by heat effects on the housing surrounding the fuse.

In the temperature rise test, the Example product of the present invention showed a lower value of about 6 to 7°C when compared to the conventional product.

Also in the intermittent current durability test, when compared with the conventional product, the product of the example of the present invention did not cause surface oxidation, and no abnormalities were observed overall.

In the vibration durability test, there were no abnormalities in both the conventional product and the example product of the present invention, and there was no difference between them.

〔Effect of the invention〕

As detailed above, according to the block type fuse according to the present invention, the fusible portion extends horizontally;
A pair of terminal parts extending perpendicularly downward from both ends of the fusible body part are integrally molded from a copper alloy material, and a narrow fusing part is provided in the longitudinal middle part of the fusible body part. A pair of heat absorbing parts each having a concave shape in the longitudinal direction are formed with the fusing part sandwiched therebetween,
Further, a heat absorbing body is provided, which includes a heat absorbing member made of tin or a tin alloy, a flux disposed at the longitudinal center portion or the outer circumferential surface of the heat absorbing member, and a conductive member surrounding and covering the longitudinal outer circumferential surface of the heat absorbing member, Since the heat absorbing body is fitted and fixed in the recess of each heat absorbing part, even if a current of about twice the rated current flows through the fusible part, the heat generated at the fusing part will not be transferred to the heat absorbing part. , the flux is melted and activated, and the heat absorbing member is melted, and together with the activated flux, the surface of the copper alloy of the fusible body is wetted, thereby forming an alloyed layer locally on the base material. By doing so, the fusing time can be accelerated and the fusing action can be achieved quickly when the predetermined temperature is reached. Also, in order to diffuse and alloy the tin component into the copper base material,
The melting temperature is lowered and redness can be suppressed. Therefore, the thermal influence on the fuse surroundings can be prevented as much as possible, deterioration due to heat cycles can be effectively prevented, and the structure is improved. It also has excellent features such as being relatively simple and easy to implement.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing the overall structure of an embodiment of a block-type fuse according to the present invention, FIG. 2 is an enlarged cross-sectional view of the section taken from FIG. 1 shown in FIG. - shows a longitudinal cross-sectional view of the line part,
Further, FIG. 4 is a cross-sectional view corresponding to FIG. 2 according to another embodiment of the same. 1... Block type fuse, 2... Fusible part,
3... Terminal portion, 4... Narrow fusing portion, 5... Heat absorbing portion, 6... Heat absorbing body, 7... Heat absorbing member, 8... Flux, 9... Conductive member.

Claims (1)

[Claims] 1. It has a fusible body part that extends horizontally, and a pair of terminal parts that extend vertically downward from both ends of this fusible body part, and each of these parts is integrally molded from a copper alloy material, and the longitudinal direction of the fusible body part In the middle part in the direction, a narrowed fusing part and a pair of heat absorbing parts each having a concave shape in the longitudinal direction are formed with the fusing part sandwiched therebetween. A heat absorbing body made of a conductive member that surrounds and covers the flux disposed at the center portion in the longitudinal direction or the outer circumferential surface thereof is provided, and the heat absorbing body is fitted and fixed in the recess of each of the heat absorbing portions. A block-shaped fuse characterized by its structure.