KR800001404Y1 - Tense fuse - Google Patents

Abstract

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Description

Tension fuse device

1 is a Cu-Zn-based state diagram.

2 is a pull-temperature characteristic diagram for β-brass and constantan.

3 is a resistance-temperature characteristic diagram for β-brass and constantan.

4 is a current-time characteristic diagram of a β-brazed fuse line.

5 is a schematic analysis diagram for obtaining the current-time characteristic of FIG.

6 is a schematic diagram showing each example of a state of use of the fuse wire used in the present invention.

7a is a plan view of an embodiment of the present invention.

(b) is a front view which cut | disconnected a part of (a) figure.

(c) is the bottom view of FIG.

The present invention relates to a fuse device using a current while applying a tension.

The communication fuse wire is required to have a small value of shear current / rated current in order to protect the communicator well and not to burn intimate semiconductor elements, organic heat-transfer materials, etc. due to a rise in temperature when a disturbance current flows. In addition, in an automatic telephone switch having a communication line of tens of thousands, it is desired to have a function of indicating (detecting) which fuse device of the fuse device of each fuse device installed on each line is cut.

However, generally used brass is α phase (α solid solution) of less than 35% of Zn shown in the Cu (copper) -Zn (zinc) state diagram of FIG. 1, or β phase when the ratio of Zn is increased to 40%. Appears and becomes alpha + beta phase. When the ratio of Zn is increased to 43%, the β phase becomes 80% or more, and when the ratio of Zn reaches 45%, the β phase approaches 100%, and at the same time, the γ phase starts to occur. The γ phase suddenly becomes vulnerable, and plastic processing such as cutting edges is impossible at all.

The present invention is 43-45% zinc, the remainder is copper, and the diameter of the wire is made by repeating the low temperature annealing and cutting process of 350 ± 50 ℃ for brass whose β phase is more than 80%. It is possible to make it as thin wire of about 0.06mm and to cut current while exerting the electric current while applying tension to β-brass wire having regular-irregular transformation point between 454-468 ℃ to exert its performance as fuse. In this case, it is to provide a tension fuse device, characterized in that to act both or one of the ON and cut display operation of the alarm circuit.

Hereinafter, the present invention will be described in detail, the physical constant at room temperature of β-brass is the same as in the first table.

[Table 1]

The most characteristic feature of this brass is the regular-irregular transformation point between 454 and 468 ℃, and below this temperature, the atoms of zinc are arranged at the center of the cubic lattice in the center of copper and 8 to form a regular grid of Cu-Zn. When the temperature becomes higher than the transformation point, atoms of copper and zinc are randomly mixed and arranged at lattice points. Accompanied by these rule-irregular transformations, the following characteristic changes are not found in other metals or alloys.

Figure 2 shows the temperature dependence of the tensile force with respect to β-brass and constantan (the rest of Ni 43-46%), and Figure 3 shows the temperature dependence of its electrical resistance. As can be seen, in solid solution such as constantan, the tensile strength generally decreases gradually as the temperature rises, while in β-brass, the decrease from room temperature to 200 ℃ is 250 ℃ even though the decrease rate is lower than that of the constantan. In the vicinity, the decrease is drastically increased, and if it exceeds 300 ° C, the decrease is more sharply reduced, and at 450 ° C, the decrease is reduced to ² kg / nm ² corresponding to about one fourth of 70-100 kg / nm ² at normal temperature.

As apparent from Fig. 3, the temperature coefficient of the electrical resistance of β-brass is approximately constant at 2.3 × 10 ^{−3 up} to 300 ° C, but when it is higher than that, it increases rapidly nonlinearly and reaches 470 ° C. 16-17 μΩ / cm, which is about three times 0.1 μΩ / cm.

In the present invention, while applying a current to the β-brass wire having the specific properties as described above in the manner of Fig. 6 (a) (b) and (c) it is used as a fuse.

In the case of FIG. 6A, tension is applied to both ends of the β-braze fuse line 11, and in this case, two spring terminals are provided. It is possible.

In the case of FIG. 6B, one end of the fuse line 11 is fixed and the tension is applied to the other end. In this case, since there is only one spring terminal, the alarm circuit is closed or one of the cut display operations is performed.

In the case of FIG. 6c, the fuse 11 is tensioned to fix both ends and the tension is applied by applying pressure or a tension force in the middle thereof. In this case, since there is only one spring terminal, as in FIG. One of closing or fuse cutting display operations is performed. In particular, in the case of Fig. 6 (a) and (b), the cut portion of the fuse wire acts to pull or drop rapidly due to the tension, which is effective to cut off the sparks generated at the time of short-circuit, and to multiply the breaking capacity compared to the tensionless fuse. There is an advantage to increase.

7 (a), 7 (b) and 7 (c) show an example in which the present invention is realized as a fuse device for protecting a relay circuit of an automatic telephone exchange.

In other words, the fuse line 11 made of β-brass is disposed in the tube portion 2 of the insulating base 1 and is installed between the metal spring terminals 4 and 5, which corresponds to the case of FIG. When the fuse line 11 is cut off, the spring terminals 4 and 5 spring up in the direction in which they are separated from each other. For example, the display 6 of the spring terminal 4 performs the cutting display operation. (5) makes the closing of the alarm circuit.

The rated current, wire diameter, mechanical and electrical performance, conditions of use, and fuse characteristics of the β-brased fuse wire 11 used in this tension fuse apparatus are shown in FIG. do.

[Table 2]

As described above, when an electric current is used while applying a tension to the β-brased fuse wire, when the excessive current flows, the temperature of the fuse wire increases due to the "joule" heat, thereby increasing the electrical resistance and thus promoting a temperature rise. As a result, the tensile force of the fuse line decreases sharply, and the fuse line is cut at the moment when it falls below the working tension.

Since the above mechanism is synergistic, the operating tension is selected to be 5-35% of the cutting load at room temperature of the fuse wire, and as shown in FIG. 4, the sensitive current-time characteristic which is not obtained with other single metals or alloys is obtained. Obtained. If a fuse wire is used with other single metals or alloys with internal resistance, creep breakage occurs when the applied tension is increased, whereas if the applied tension is reduced, the glow or incandescent state occurs during cutting. Therefore, it burns the surrounding organic dielectric material or changes the characteristics of semiconductor devices such as transistors and diodes. Here, as in the above-described embodiment, when the β-braze fuse wire is applied with a tension of 20 ± 15%, the temperature at the time of cutting is 400 ° C. or higher, as can be easily understood in the characteristics of FIGS. 2 and 3. It cannot be reached, and there is almost no creep disconnection during rated current energization.

The tension fuse device of the present invention having the above advantages is suitable for the protection of relay circuits such as cross type automatic telephone exchangers, electronic automatic telephone exchangers, or the protection of electronic circuits including semiconductor elements such as transistors and diodes.

Next, the effect of the tension fuse device of the present invention described so far will be explained theoretically.

The i-t curve showing the current-time characteristic of the fuse line when the tension is applied is obtained by solving the simultaneous equations of the following formulas (1) and (2).

Temperature-Time Curve: u = f (t) ---------------- (1)

Tensile force-temperature curve: τ = g (u) ------------- (2)

Where u denotes temperature (° C), t denotes time (sec), and τ denotes tension (g).

Since these are generally nonlinear equations, it is more convenient to solve them by the schematic analysis method shown in FIG.

Next, such a drawing method is explained.

First, the curve with the current value in as the parameter,

u = f (t) | i = in (n = 1,2… n) ---------------- (1 ')

Is the t-u curve at the first upper limit, and the relationship between the cutting load and the temperature determined by the material of the fuse line and the diameter of the line at the second upper limit,

τ = g (u) | d = d _o ------------------- (2 ')

Is plotted as a u-τ | d = d _o curve. Where d is the diameter of the line and d _o is the diameter of the particular line.

To find the it curve from these two curves, use the following procedure. Now, the case where the tension acting on the fuse line is τ ₁ will be described.

However, since τ> τ ₁ > τ ₀ , τ ₀ is the cut load of the fuse wire at room temperature. If 0τ ₁ is defined as the tension τ ₁ on the τ axis of the second upper limit and a parallel line is plotted on the longitudinal axis at τ ₁ , the intersection point with the u-τ | d = d _o curve is u ₁ , and this u ₁ is the tension τ _1. Since the cutting temperature of the fuse line in this case is displayed, the current i ₁ , i ₂ ... the intersection with the tu curve when i ₅ flows t ₁ , t ₂ . If t ₅ , these indicate cutting times, so the straight line drawn parallel to the longitudinal axis through these points and 0i ₁ , 0i ₂ . 0i ₅ is the current i ₁ , i ₂ . Take the magnitude of i ₅ , find the point of intersection with the straight line parallel to the horizontal axis by those points, and draw a curve connecting these points.

As can be seen from the above diagram, the i-t characteristic of the fuse acting under tension (current-time characteristic)

i = h (t) ----------------- (3)

Is the solution to the system of equations (1 ') and (2'). However, since Figs. 3 'and 2' of Formula 1 'are determined in Fig. 2, it is proved that the change of specific physical properties based on the rule-irregular transformation of the brass fuse wire is extremely effective.

In addition, depending on the ambient atmosphere using the tension fuse device of the present invention, nickel, silver, cadmium, tin, etc. may be plated on β-brass wire to prevent natural cutting due to corrosion.

As described above, according to the present invention, a tension is applied to a fuse wire of 43-45% of zinc and the remainder of copper, and the β phase is made of brass of 80% or more. And a fuse line cut detection function that enables both or one of the cut display operations, and has a sensitive current-time characteristic, and contributes to the rapid recovery of circuit failure in a temperature range where semiconductor devices and organic insulators are not burned. A tension fuse device can be provided.

Claims (1)

Tension is applied to the fuse wire 11 whose component is 43-45% of zinc and the remainder is copper and β phase is made of brass of 80% or more. Tension fuse device, characterized in that to enable the cutting detection operation by the reaction of.