TWI450301B - Repeatable fuse - Google Patents

Description

Repeatable fuse [related application]

The present application claims the priority of the Korean Patent Application No. 10-2010-0088282, filed on Sep. 9, 2010, and the entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire content The manner is incorporated herein.

BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to a reproducible fuse, and more particularly to a reproducible fuse that can be manufactured in small size for accurate operating temperature and current rating properties for various operating temperatures and current ratings. wire.

In general, all appliances that use electricity always have an opportunity for an accident caused by overheating due to abnormal overcurrent or external overheating in the circuit. Conventionally, in order to prevent overheating, a disposable fuse made of a material which is blown and cut by heat generated when an overcurrent flows has been used. However, since the disposable fuse is not expensive but can no longer be used, the disposable fuse should be replaced by a new disposable fuse after being blown, which disadvantageously results in a large cost. To solve this problem, a two-metal thermal switch combined with two different metal plates having different thermal expansion coefficients is used in place of the disposable fuse. However, bimetal thermal switches have the problem that they only serve as contact points and have large operational deviations depending on temperature, as well as additional devices such as limit switches.

Although polymer fuses using special polymers have been developed, polymer fuses also have problems in that their material chemistry is unstable, and there is a fire attributable to an explosion or the like in the event of a sudden change in voltage and current. The danger. In addition, polymer fuses are unstable in materials and have low durability and slow reaction times, which may lead to an emergency.

At the same time, electrical devices have recently required fuses that allow surface mounting due to the devices typically mounted on the surface of printed circuit boards. However, since the soldering in the process of surface mounting a conventional disposable fuse requires a temperature of 270 ° C or more, the fuse is blown due to its intrinsic properties and thus cannot be surface mounted. Of course, although the bimetal thermal switch can solve this problem, it is difficult to surface mount the switch due to its bulkiness and the possibility of deterioration caused by the soldering temperature.

To solve these problems, shape memory alloy fuses have been developed using reusable and surface mountable elastic members such as shape memory alloys. Since the shape memory alloy has a small temperature deviation, it provides a reproducible fuse with high reliability.

However, the shape memory alloy spring wire and the bias spring wire of the shape memory alloy fuse (which provides the tension corresponding to the shape memory alloy spring) have not been established, such as the wire diameter, the number of wire turns, and the like. Dimension makes it practical to manufacture shape memory alloy fuses by trial and error through extensive experimentation. Therefore, the manufacturing time is prolonged and the manufacturing cost is increased due to the materials used in the experiment, thereby deteriorating the productivity of the shape memory alloy fuse.

The present invention provides a reproducible fuse that can be manufactured in a small body and that can be used repeatedly.

Additionally, the present invention provides a repeatable fuse having accurate operating temperature and current rating properties for various operating temperatures and current ratings.

Moreover, the present invention provides a repeatable fuse with improved productivity by reducing manufacturing time and cost.

According to an aspect of the present invention for achieving the objects, a reproducible fuse comprising: a shape memory alloy spring; and a bias spring corresponding to the shape memory alloy spring, wherein the shape memory alloy spring The coil shape is formed to have a wire diameter of 0.15 mm to 0.50 mm and a wire number of 3.5 to 7.0.

Preferably, the shape memory alloy spring has a wire diameter of 0.20 mm to 0.40 mm and a wire diameter of 4.0 to 6.5.

The shape memory alloy spring may be formed to have an outer diameter of 7.0 to 8.5 times the diameter of the wire.

The average spacing of the shape memory alloy springs is preferably from 1.0 mm to 1.5 mm.

The wire diameter of the biasing spring is preferably 60% to 65% of the wire diameter of the shape memory alloy spring.

The biasing spring has a wire diameter of 0.10 mm to 0.30 mm. The number of turns of the biasing spring is greater than the number of turns of the shape memory alloy spring and is 4.0 to 7.5.

Preferably, the biasing spring has a wire diameter of 0.15 mm to 0.25 mm and a wire diameter of 5.0 to 6.0.

The average pitch of the biasing springs is preferably from 1.0 mm to 1.5 mm.

The height of the biasing spring is preferably from 120% to 125% of the height of the shape memory alloy spring.

The shape memory alloy spring preferably comprises nickel (Ni) and titanium (Ti).

The shape memory alloy spring may include at least one of cobalt (Co), molybdenum (Mo), tungsten (W), and chromium (Cr).

The bias spring may comprise SUS stainless steel, and the stainless steel may be coated with at least any one of Ni, Cu, Ag, Au, and Sn.

According to the foregoing embodiment of the present invention, it is possible to provide a reproducible fuse manufactured in a small body type, and the operational properties are maintained even when the reusable fuse is repeatedly used.

Additionally, the present invention can provide a repeatable fuse having accurate operating temperature and current rating properties for various operating temperatures and current ratings.

Furthermore, the present invention can provide a repeatable fuse in which the optimum design parameters of the shape memory alloy spring and the bias spring for the repeatable fuse can be presented, thereby reducing manufacturing time and cost and thereby improving productivity .

The preferred embodiments of the present invention can be understood in more detail from the following description taken in conjunction with the drawings.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. At the outset, it should be noted that like reference numerals are used to designate similar components or parts. When describing the present invention, the relevant A specific description of a function or configuration is made so that the gist of the present invention is not obscured.

1 is an exploded perspective view illustrating a repeatable fuse according to an embodiment of the present invention, and FIGS. 2 and 3 show an operational state of a repeatable fuse according to an embodiment of the present invention, and FIG. 4 is a diagram illustrating A cross-sectional view of a portion of a repeatable fuse of an embodiment of the invention.

As shown in FIGS. 1 through 4, a repeatable fuse according to an embodiment of the present invention includes: a housing 100; a first lead terminal 200 disposed in one side of the housing; and a second lead terminal 300 Is insulated from the outer casing and disposed in the other side of the outer casing; a spindle 400 disposed inside the outer casing to be electrically connected to the first lead terminal and connected to the second lead terminal or disconnected from the second lead terminal And an elastic member, that is, a shape memory alloy spring 510 and a biasing spring 520 disposed inside the outer casing to be coupled to the shaft and electrically connect or disconnect the second lead terminal 300 to the shaft.

The outer casing 100 has an inner space and is formed in a box shape extending in a longitudinal direction thereof to accommodate and protect the shaft 400, the shape memory alloy spring 510, and the biasing spring 520. The outer casing 100 may be in contact with the first lead terminal 200 to be electrically connected thereto such that the outer casing 100 is preferably formed of a conductive material. Of course, according to an embodiment, the outer casing 100 may be formed of a non-conductive material. The outer casing 100 may be formed to have a cross section perpendicular to the longitudinal direction of a circle, an ellipse, a polygon, or the like such that the outer casing may have a box shape of a cylinder, an elliptical cylinder, a prism, or the like. In this embodiment, the outer casing will be described as having the shape of a cylindrical box as shown in FIG.

Further, a catching protrusion 120 is formed to protrude horizontally inward from a predetermined position of the inner circumferential surface of the outer casing 100 to support the shape Memory alloy spring 510. The shape memory alloy spring 510 and the biasing spring 520 are mounted between the latch projection 120 and one end of the outer casing 100 on which the second lead terminal 300 is disposed. At this time, the design parameters of the shape memory alloy spring 510 and the bias spring 520 are accurately controlled, which will be described later in detail.

The first lead terminal 200 as a member for receiving external power or connected to a power source is made of a conductive material. The first lead terminal 200 is provided at one side of the outer casing 100, that is, in this embodiment, at the other end of the cylindrical case-shaped outer casing 100. The first lead terminal 200 is electrically connected to the shape memory alloy spring 510 or the bias spring 520 via the outer casing 100 or an additional connecting member (not shown), and is electrically connected via the shape memory alloy spring 510 or the bias spring 520. Connected to the shaft 400. For example, if the outer casing 100 is made of a conductive material and the shape memory alloy spring 510 or the bias spring 520 is in contact with the inner side of the outer casing 100 or the latch protrusion 120, the first lead terminal 200 is electrically connected to the first lead terminal 200 via the outer casing 100. Axis 400. In addition, a shape memory alloy spring 510 or a biasing spring 520 is coupled to one side of the shaft 400 and electrically connected thereto. Although the first lead terminal 200 is provided in a rod shape in this embodiment, the present invention is not limited thereto. That is, if the first lead terminal 200 is electrically connected, it may have any shape.

The second lead terminal 300 as a component for electrical connection transfers, for example, the current received from the first lead terminal 200 to the electronic/electrical device and is made of a conductive material. The second lead terminal 300 is configured to be spaced apart from the first lead terminal 200 by a predetermined distance. In this embodiment, the cylindrical case-shaped outer casing 100 has a second lead terminal 300, and the second lead terminal 300 It is formed in one end of the outer casing 100 and opposed to the other end of the outer casing in which the first lead terminal 200 is formed. Here, the second lead terminal 300 may be configured in such a manner that it penetrates the one end of the case and is inserted therein. However, the present invention is not limited thereto, and the second lead terminal 300 is spaced apart from the one end of the outer casing. That is, if the shaft 400 is moved to be connected or disconnected from the second lead terminal 300, the second lead terminal 300 may be disposed at any position.

The second lead terminal 300 is connected or disconnected from the first lead terminal 200 by the shaft 400. Because the second lead terminal 300 is electrically connected to the first lead terminal 200 via the shaft 400, the second lead terminal 300 is configured to be insulated from the outer case 100 electrically connected to the first lead terminal 200. To this end, the end of the outer casing 100 configured with the second lead terminal 300 is formed to have an opening such that the second lead terminal 300 is spaced apart from the outer casing 100 or the outer surface of the outer lead 100 through which the second lead terminal 300 is coated may be coated with an insulator.

A shaft 400 as a member for connecting or disconnecting the first lead terminal 200 and the second lead terminal 300 is provided inside the outer casing 100. Similar to the outer casing 100 extending in the longitudinal direction, the shaft 400 may be provided in the shape of a shaft extending in its longitudinal direction. The shaft 400 may be formed to have a cross section perpendicular to the longitudinal direction, such as a circle, an ellipse, a polygon, or the like, and preferably has the same cross section as the cross section of the outer casing 100. In this embodiment, as shown in FIG. 1, the shaft 400 is formed to have a cylindrical shape to conform to the cylindrical box-shaped outer casing 100. The shaft 400 can be electrically connected to the first lead terminal 200 by a shape memory alloy spring 510. For this purpose, the shaft 400 is preferably formed of a conductive material. As shown in FIGS. 2 and 3, the shaft 400 is elongated and compressed by the shape memory alloy spring 510 and the biasing spring 520. Moving to reciprocate within the outer casing 100 in the longitudinal direction, thereby electrically connecting (see FIG. 2) to the second lead terminal 300 or disconnecting from the second lead terminal 300 (see FIG. 3). Therefore, as the shaft 400 is connected to or disconnected from the second lead terminal 300, the first lead terminal 200 and the second lead terminal 300 are also connected or disconnected from each other. A support 410 capable of supporting the shape memory alloy spring 510 or the bias spring 520 may be formed in at least a portion of one side of the shaft 400 such that the support 410 may be coupled to the shape memory alloy spring 510 or the bias spring 520. The support 410 may be formed to protrude from the side of the shaft 400 in a direction perpendicular to the axial direction of the shaft 400. The support 410 may be formed continuously or discontinuously around one side of the shaft 400. That is, if the shaft 400 is connectable to the shape memory alloy spring 510 or the biasing spring 520, the support 410 may have any shape.

The shape memory alloy spring 510 and the biasing spring 520 are members for connecting or disconnecting the second lead terminal 300 and the shaft 400. These springs are disposed within the outer casing 100 to elongate or compress in the longitudinal direction of the outer casing 100. The shape memory alloy spring 510 is coupled to the inner side of the outer casing 100. In this embodiment, the shape memory alloy spring 510 is coupled to the latching projection 120 of the outer casing 100. Next, a biasing spring 520 is coupled to the shaft 400 or the support 410 of the shaft to thereby electrically connect thereto. Although the shape memory alloy spring 510 is disposed on the left side of the shaft 400 and the bias spring 520 is disposed on the right side of the shaft 400 in this embodiment, the springs 510 and 520 may be configured to be interchanged in position. That is, the biasing spring 520 can be disposed on the left side of the shaft 400 and the shape memory alloy spring 510 can be disposed on the right side of the shaft 400. In this case, contrary to the condition in which the fuse can be repeated in the normal state, in the normal state The repeatable fuse is broken.

The foregoing is only for describing some of the embodiments in which the design dimensions of the shape memory alloy spring 510 and the biasing spring 520 which will be described later can be applied, and embodiments in which the design dimensions of the present invention are not intended to be limited are applicable. .

For a reproducible fuse having a shape memory alloy spring, the inventors have proposed a shape memory alloy spring exhibiting accurate operating temperature and rated current properties by fabricating shape memory alloy spring 510 and biasing spring 520 under various design conditions. 510 design parameters. In addition, design parameters of the biasing spring 520 corresponding to the design conditions of the shape memory alloy spring are proposed. Hereinafter, these design parameters will be described below.

The shape memory alloy spring 510 can be made of an alloy containing nickel (Ni) and titanium (Ti). It is possible to fabricate three springs having different operating temperature properties by varying the composition ratio as shown in Table 1 below. Of course, it is for illustrative purposes only, and the operating temperature is not limited thereto. Further, a spring having a plurality of operating temperature properties can be produced by containing at least one of cobalt (Co), molybdenum (Mo), tungsten (W), and chromium (Cr).

Referring to Figure 4, a shape memory alloy spring 510 and a biasing spring will be described. 520 design parameters. Herein, "wire diameter Φ1 or Φ2" means the diameter of the wire of the spring 510 or 520 (the length and width of the cross section in the case of a quadrilateral spring), and "the number of turns of the wire T1 or T2" means a coil-shaped spring The number of 510 or 520. In addition, "average pitch P1 or P2" means an average value of the intervals of the coil-shaped springs (interval between adjacent turns of the spring wires), and "height H1 or H2" means the total length of the springs 510 or 520. . Also, "outer diameter OD1 or OD2" means the diameter of a circle defined by the spring 510 or 520.

The shape memory alloy spring 510 is allowed to be formed in a coil shape to have a wire diameter Φ1 of 0.15 mm to 0.50 mm and a wire number T1 of 3.5 to 7.0. Thus, the operating temperature and rated current properties can be exhibited. Preferably, it has been experimentally confirmed that when the wire diameter Φ1 is 0.20 mm to 0.40 mm and the number of wire turns T1 is 4.0 to 6.5, more accurate operating temperature and rated current properties are exhibited. At the same time, the coil springs can have various shapes such as a circle, a polygon, and the like. However, the coil spring is preferably formed to correspond to the inner shape of the outer casing 100 to facilitate manufacture.

The outer diameter OD1 of the shape memory alloy spring is allowed to be about 7.0 to 8.5 times the wire diameter Φ1. For example, if the wire diameter Φ1 is 0.25 mm, the outer diameter OD1 of the spring is allowed to be approximately 1.75 mm, and if the wire diameter Φ1 is 0.3 mm, the outer diameter OD1 of the spring is allowed to be approximately 2.50 mm. Further, if the wire diameter Φ1 is 0.35 mm, the outer diameter OD1 of the spring is allowed to be approximately 3.00 mm. Thus, the minimum radius of curvature (3 to 5 times the diameter of the wire) required to process the shape memory alloy spring 510 can be ensured and used for expansion after heat treatment (about 10% or 10% The space of the upper expansion ratio, the space for assembling the outer casing 100 and the spring, and the like can be ensured.

To ensure proper elasticity of the shape memory alloy spring 510, the average pitch P1 of the shape memory alloy spring is allowed to be 1.00 mm to 1.50 mm. When the average pitch P1 is more than 1.50 mm or less than 1.00 mm, the appropriate elasticity used in the repeatable fuse is not obtained, and when the average pitch P1 is 1.00 mm to 1.50 mm, the optimum elasticity is obtained, in which case The experiment confirmed.

The average pitch P1 and the number of wire turns T1 are determined, and then the height H1 of the spring 510 can be determined. For example, since the two ends of the spring 510 overlap, when the average pitch P1 is 1.50 mm and the number of turns T1 is 5.0, the effective number of turns T1 should be 3.0 and thus the height H1 of the spring 510 is 1.50 mm. ×3.0 = 4.50 mm.

The wire diameter Φ1, the number of turns of the wire T1, the outer diameter OD1, the pitch P1, and the height H1 are designed in the range proposed above, and then the shape memory alloy spring 510 is manufactured.

The condition of the biasing spring 520 will be determined to obtain a tension corresponding to the design parameters along with the design parameters of the shape memory alloy spring 510.

After determining the design parameters of the shape memory alloy spring 510 in the foregoing range, the experiment for the condition of the biasing spring 520 is repeated, and the tension corresponding to the design parameters is generated in the condition of the biasing spring 520. As a result, it was confirmed that the accurate operational properties of the repeatable fuse can be implemented when the wire diameter Φ2 of the bias spring 520 is on average about 60% to 65% of the wire diameter Φ1 of the shape memory alloy spring 510. In addition, the wire that can be used in the biasing spring 520 is confirmed. When the number of turns T2 is greater than the wire diameter T1 of the shape memory alloy spring 510 by 0.5, the precise operational properties of the repeatable fuse are implemented.

More specifically, the biasing spring 520 is made of SUS stainless steel (for example, SUS304), or stainless steel coated with at least one of Ni, Cu, Ag, Au, and Sn may be used in order to adjust the resistance of the biasing spring 520. . Further, the biasing spring is formed to have a wire diameter Φ2 of 0.10 mm to 0.30 mm. Further, the biasing spring 520 is formed to have a shape corresponding to the coil shape of the shape memory alloy spring 510 and has a wire number T2 larger than the wire number T1 of the shape memory alloy spring. Preferably, the number of turns T2 of the biasing spring 520 is greater than the number of turns T1 of the shape memory alloy spring, for example, the number of turns T2 is in the range of 4.0 to 7.5. More preferably, it has been experimentally confirmed that when the biasing spring 520 has a wire diameter Φ2 of 0.15 mm to 0.25 mm and a wire number of 5.0 to 6.0, accurate operating temperature and rated current properties are exhibited.

For reasons similar to those of the shape memory alloy spring 510, the biasing spring 520 is preferably formed to have an outer diameter OD2 similar to the outer diameter OD1 of the shape memory alloy spring.

Further, in order to ensure proper elasticity of the biasing spring 520, the distance P2 between the biasing springs is allowed to be 1.00 mm to 1.50 mm and the height H2 thereof is larger than the height H1 of the shape memory alloy spring by about 20% to 25%. .

As described above, it is possible to appropriately combine the wire diameter Φ1 of the shape memory alloy spring 510, the number of wire turns T1, the outer diameter OD1, the pitch P1, and the height H1 with the wire diameter Φ2 of the bias spring 520, and the number of wire turns T2. , outer diameter OD2, pitch P2 and height H2 are manufactured to have 2A to 20A A repeatable fuse of rated current.

Further, if the shape memory alloy spring 510 is made of a shape memory alloy having a different transition temperature, it is possible to not change the wire diameters Φ1 and Φ2 of the shape memory alloy spring 510 and the bias spring 520, and the number of turns T1 And T2, outer diameter OD1 and OD2, pitches P1 and P2, and heights H1 and H2 to produce a repeatable fuse that can be operated at various temperatures (such as 75 ° C, 95 ° C, 115 ° C, and the like) . That is, the change in the operating temperature can be performed by changing the composition of the shape memory alloy, and the wire diameter Φ2 of the biasing spring 520 corresponding thereto is designed to gradually differ depending on the operating temperature. For example, a repeatable fuse of 95 ° C can reduce wire diameter by about 5% to 12% compared to a recyclable fuse of 75 ° C, and a repeatable fuse of 115 ° C can be used with 95 The repeatable fuse of °C reduces the wire diameter by about 5% to 12%.

If the shape memory alloy spring 510 and the biasing spring 520 having the aforementioned design parameters are used, it is possible to manufacture a micrometer having a diameter of about 1.5 mm (in the case of a quadrilateral, the length and width of the cross section) and a length of about 4 mm. (subminiature) a repeatable fuse. Even in the case where the rated current is 20A of a large current, it is possible to manufacture a small body having a diameter of about 4.5 mm (in the case of a quadrilateral, the length and width of the cross section) and a length of about 10 mm or less. Repeatable fuses.

The technical significance for the aforementioned parameter values will be described via an example of the following experiment. In the example of the following experiment, "◎" designates "excellent" and means that the reproducible fuse is excellent in operation close to the center of the operating temperature range. In addition, "○" specifies "good" and means that the operating temperature deviation is within ±5 degrees. The medium and repeatable fuses operate well near the center of the operating temperature range. "△" specifies "average" and means that the operating temperature deviation is slightly larger and the rated current is unstable, but a repeatable fuse can be used. "X" specifies "impossible operation" and means that the fuse with too high operating temperature or repeatability cannot be operated at all. The rated current is a current that can be allowed to flow stably in the device at a normal temperature for a long time, and the actual breaking current of the fuse operation (that is, in the case of a non-repeatable fuse, the fuse is melted) Destroyed) is 2 or 3 times the rated current.

Example 1 of the experiment

Several experiments with respect to the shape memory alloy spring 510 having an operating temperature property of 75 degrees (±5 degrees) were performed with the wire diameter Φ1 and the number of wire turns T1 changed so that the results shown in Table 2 below were obtained.

Referring to Table 2, it can be seen that if the wire diameter Φ1 of the shape memory alloy spring 510 is less than 0.15 mm, it is impossible to manufacture a spring, or even if possible, The spring is also almost non-elastic.

When the wire diameter Φ1 is 0.15 mm and the number of wire turns T1 is 3.5 or 4.5, it can be seen that although the operating temperature deviation is slightly large and the rated current is unstable, even a repeatable fuse is manufactured to have a small body type (for example, Repeatable fuses ("average") can still be used with a diameter of about 1.5 mm and a length of about 4 mm.

In addition, when the wire diameter Φ1 is 0.15 mm and the number of wire turns T1 is 4, it can be seen that the operating temperature deviation is ±5 degrees and the repeatable fuse is relatively well operated near the center of the operating temperature range ("good" ).

It can be seen that a repeatable fuse can be used for the rated current of 2A when the wire diameter Φ1 is 0.20 mm, wherein the repeatable fuse "good" operation when the wire number T1 is 3.5 or 4.5, and When the number of turns of the wire T1 is 4.0, the repeatable fuse is close to the center of the operating temperature range and is excellently operated ("excellent").

Example 2 of the experiment

Several experiments on the shape memory alloy spring 510 having an operating temperature property of 95 degrees (±5 degrees) were performed with the wire diameter Φ1 and the number of wire turns T1 changed so that the results shown in Table 3 below can be obtained.

[Table 3] Manufacturing experiment of reproducible fuse for 10A medium rated current

Referring to Table 3, it can be seen that when the wire diameter Φ1 of the shape memory alloy spring 510 is 0.35 mm, a repeatable fuse can be used for the rated current of 10 A.

In detail, it can be seen that the repeatable fuse operates "goodly" when the wire diameter Φ1 is 0.35 mm and the number of wire turns T1 is 5.0 or 6.0. In addition, it can be seen that the repeatable fuse operates "excellently" when the wire diameter Φ1 is 0.35 mm and the number of wire turns T1 is 5.5.

At the same time, it can be seen that when the wire diameter Φ1 is 0.40 mm, a repeatable fuse can be used unsteadily for a rated current of 10 A or more.

Specifically, it can be seen that the repeatable fuse is "generally" operated when the wire diameter Φ1 is 0.40 mm and the wire number T1 is 5.5 or 7.0, and when the wire diameter Φ1 is 0.40 mm and the wire number T1 is The reproducible fuse is "good" at 6.0.

Example 3 of the experiment

Performing a shape memory alloy spring with an operating temperature property of 115 degrees (±5 degrees) with a change in wire diameter Φ1 and wire number T1 Several experiments at 510 resulted in the results shown in Table 4 below.

According to Table 4, when the shape memory alloy spring 510 has a wire diameter Φ1 of more than 0.50 mm, it can be seen that although it is possible to manufacture a spring and obtain an effective rated current, the repeatable fuse having the spring manufactured above is obtained. It has a diameter of more than 4.5 mm (in the case of a quadrilateral spring, the length and width of the cross section) and a length of more than 10 mm, which makes it difficult to miniaturize the device.

Meanwhile, when the wire diameter Φ1 is 0.40 mm, it can be seen that a repeatable fuse can be used for the rated current of 20 A.

In particular, when the wire diameter Φ1 is 0.40 mm and the number of wire turns T1 is 6.0 or 7.0, it can be seen that the repeatable fuse operates "good". In addition, when the wire diameter Φ1 is 0.40 mm and the number of wire turns T1 is 6.5, it can be seen that the repeatable fuse is "excellently" operated.

Meanwhile, when the wire diameter Φ1 is 0.50 mm, it can be seen that the repeatable fuse can be used steadily for the rated current of 20 A or more.

In particular, it can be seen that when the wire diameter Φ1 is 0.50 mm and the number of wire turns T1 is 6.5 or 7.5, the repeatable fuse is "generally" operated, and when the wire diameter Φ1 is 0.50 mm and the number of wire turns T1 At 7.0, the repeatable fuse is "excellently" operated.

If the design parameters of the shape memory alloy spring 510 have been determined, the biasing spring 520 is designed such that it has a tension corresponding to the shape memory alloy spring 510. Therefore, the spring outer diameter OD2 as the design parameter of the biasing spring 520 is equal to or smaller than the outer diameter OD1 of the shape memory alloy spring 510 to be assembled with the outer casing 100. In addition, since it is in the initial assembled state, the bias spring applies tension and the shape memory alloy spring should be suppressed, and the wire diameter T2 of the bias spring should be slightly larger than the wire number T1 of the shape memory alloy spring 510. Under this condition, the range in which the wire diameter Φ2 of the biasing spring 520 can vary is narrowed.

The wire conditions of the shape memory alloy spring 510 and the biasing spring 520 that can be fabricated or will be fabricated with repeatable fuses having optimal operational properties are shown in FIGS. 5-8.

Figure 5 shows the operational properties of a repeatable fuse according to the wire diameter Φ1 of a shape memory alloy spring.

In Fig. 5, it is impossible to manufacture a spring in the area A1 in which the wire diameter Φ1 is less than 0.15 mm, or the spring is hardly elastic and thus cannot exhibit operational properties, if possible. The wire diameter is 0.15 mm to 0.20 m In the zone D1 of the rice zone and the zone D1 having a wire diameter of 0.40 mm to 0.50 mm, the repeatable fuse is operable although the operating temperature deviation is slightly present. In the zone C1 where the wire diameter is from 0.20 mm to 0.40 mm, the operating temperature deviation is a small temperature deviation near the center of the operating temperature range, and thus the repeatable fuse operates very well and exhibits optimum operational properties. . Therefore, if the wire diameter Φ1 of the shape memory alloy spring 510 is 0.15 mm to 0.50 mm, it is possible to manufacture a repeatable fuse which is operable even if it is miniaturized. For example, it is possible to manufacture a repeatable fuse that is operable even with a small body type (eg, a diameter of about 1.5 mm and a length of about 4 mm). In particular, when the wire diameter Φ1 is from 0.20 mm to 0.40 mm, it can be seen that a small repeatable fuse having optimum operational properties can be manufactured.

Figure 6 shows the operational properties of a repeatable fuse according to the number of turns T1 of the shape memory alloy spring.

In Fig. 6, the effective number of turns in the area A2 in which the number of turns T1 is less than 3.5 is not secured, so that the operational properties are not exhibited due to the lack of elasticity. In the region B2 where the number of wire turns is 3.5 to 4.0 and the region D2 where the number of turns of the wire is 6.5 to 7.0, although the operating temperature deviation is slightly present, the repeatable fuse can be operated even if it is miniaturized. In zone C2 where the number of turns of the wire is 4.0 to 6.5, the operating temperature deviation is a small temperature deviation near the center of the operating temperature range, so that the repeatable fuse operates very well and exhibits optimum operational properties. Therefore, when the wire diameter T1 of the shape memory alloy spring 510 is 3.5 to 7.0, it is possible to manufacture a repeatable fuse which is operable even if it is miniaturized. In particular, when the number of turns T1 is 4.0 to At 6.5, it can be seen that a repeatable fuse with optimum operational properties can be produced.

Figure 7 shows the operational properties of a repeatable fuse according to the wire diameter Φ2 of the biasing spring.

As described above, the biasing spring 520 is designed to achieve a tension corresponding to the previously designed shape memory alloy spring 510.

In Fig. 7, it is impossible to manufacture a spring in the region A3 where the wire diameter Φ2 is less than 0.10 mm, or the spring is hardly elastic even when possible and thus does not exhibit operational properties. In the region B3 where the wire diameter is 0.10 mm to 0.15 mm and the region D3 where the wire diameter is 0.25 mm to 0.30 mm, although the operating temperature deviation is slightly present, it is possible to manufacture a repeatable fuse which can be operated even if it is miniaturized. . In the zone C3 where the wire diameter is from 0.15 mm to 0.25 mm, the operating temperature deviation is a small temperature deviation near the center of the operating temperature range, so that the repeatable fuse operates very well and exhibits optimum operational properties. Therefore, when the wire diameter Φ2 of the biasing spring 520 is 0.10 mm to 0.30 mm, it is possible to manufacture a repeatable fuse which is operable even if it is miniaturized. In particular, when the wire diameter Φ2 is from 0.15 mm to 0.25 mm, it can be seen that a repeatable fuse having optimum operational properties can be manufactured.

Figure 8 shows the operational properties of a repeatable fuse according to the number of turns T2 of the biasing spring.

In Fig. 8, the number of turns of the wire which is effective in the region A4 in which the number of turns of the wire T2 is less than 4.0 is not secured, and the operational property is not exhibited due to the lack of elasticity. In the area where the number of wires is 4.0 to 5.0, B4 and the number of wires are 6.0 to In zone D4 of 7.0, although the operating temperature deviation is slightly present, the repeatable fuse can be operated even if it is miniaturized. In the region C4 where the number of turns of the wire is 5.0 to 6.0, the operating temperature deviation is a small temperature deviation near the center of the operating temperature range, so that the repeatable fuse operates very well and exhibits optimum operational properties. Therefore, when the number of turns T2 of the biasing spring 510 is 4.0 to 7.0, it is possible to manufacture a repeatable fuse which is operable even if it is miniaturized. In particular, when the number of turns T2 is from 5.0 to 6.0, it can be seen that a repeatable fuse having optimum operational properties can be manufactured.

Although the repeatable fuses in accordance with the present invention have been described above with reference to the accompanying drawings, the invention is not limited to the embodiments and drawings disclosed herein. Various modifications of the invention will be apparent to those skilled in the <RTIgt;

100‧‧‧ Shell

120‧‧‧Lock projections

200‧‧‧First lead terminal

300‧‧‧Second lead terminal

400‧‧‧Axis

410‧‧‧Support

510‧‧‧Shape memory alloy spring

520‧‧‧bias spring

A1‧‧‧ District

A2‧‧‧

A3‧‧‧ District

A4‧‧‧ District

B1‧‧‧

B2‧‧‧

B3‧‧‧

B4‧‧‧

C1‧‧‧ District

C2‧‧‧ District

C3‧‧‧

C4‧‧‧ District

District D1‧‧‧

District D2‧‧‧

D3‧‧‧

D4‧‧‧ District

E1‧‧‧

E2‧‧‧ District

E3‧‧‧

E4‧‧‧

Height of H1‧‧‧ shape memory alloy spring

Height of H2‧‧‧ biasing spring

OD1‧‧‧ shape memory alloy spring outer diameter

OD2‧‧‧ outer diameter of the bias spring

Average spacing of P1‧‧‧ shape memory alloy springs

Average spacing of P2‧‧‧ biasing springs

T1‧‧‧ shape memory alloy spring wire turns

T2‧‧‧Twisted spring wire turns

Φ1‧‧‧ wire diameter of shape memory alloy spring

Φ2‧‧‧ wire diameter of bias spring

1 is an exploded perspective view illustrating a repeatable fuse in accordance with an embodiment of the present invention.

2 and 3 show operational states of a repeatable fuse in accordance with an embodiment of the present invention.

4 is a cross-sectional view illustrating a portion of a repeatable fuse in accordance with an embodiment of the present invention.

Figure 5 shows the operational properties of a repeatable fuse according to the wire diameter Φ1 of a shape memory alloy spring.

Figure 6 shows the operational properties of a repeatable fuse according to the number of turns T1 of the shape memory alloy spring.

Figure 7 shows the repeatable melting according to the wire diameter Φ2 of the biasing spring. The operational properties of silk.

Figure 8 shows the operational properties of a repeatable fuse according to the number of turns T2 of the biasing spring.

400‧‧‧Axis

410‧‧‧Support

510‧‧‧Shape memory alloy spring

520‧‧‧bias spring

Height of H1‧‧‧ shape memory alloy spring

Height of H2‧‧‧ biasing spring

OD1‧‧‧ shape memory alloy spring outer diameter

OD2‧‧‧ outer diameter of the bias spring

Average spacing of P1‧‧‧ shape memory alloy springs

Average spacing of P2‧‧‧ biasing springs

T1‧‧‧ shape memory alloy spring wire turns

T2‧‧‧Twisted spring wire turns

Φ1‧‧‧ wire diameter of shape memory alloy spring

Φ2‧‧‧ wire diameter of bias spring

Claims (11)

A repeatable fuse comprising: a shape memory alloy spring; and a biasing spring, wherein the shape memory alloy spring is formed in a coil shape to have a wire diameter of 0.15 mm to 0.50 mm and a wire number of 3.5 to 7.0, And the shape memory alloy spring is formed to have an outer diameter of 7.0 to 8.5 times the diameter of the wire. The repeatable fuse according to claim 1, wherein the wire of the shape memory alloy spring has a diameter of 0.20 mm to 0.40 mm, and the number of turns of the shape memory alloy spring is 4.0. To 6.5. The repeatable fuse of claim 1, wherein the shape memory alloy spring has an average pitch of 1.0 mm to 1.5 mm. The repeatable fuse of claim 1, wherein the biasing spring has a wire diameter of 60% to 65% of the wire diameter of the shape memory alloy spring. The repeatable fuse according to claim 4, wherein the wire of the biasing spring has a diameter of 0.10 mm to 0.30 mm, and the number of turns of the coil is larger than the coil of the shape memory alloy spring. The number is from 4.0 to 7.5. The repeatable fuse according to claim 4, wherein the wire of the biasing spring has a diameter of 0.15 mm to 0.25 mm, and the number of turns of the biasing spring is 5.0 to 6.0. . The repeatable fuse of claim 5 or 6, wherein the bias spring has an average pitch of 1.0 mm to 1.5 mm. The repeatable fuse according to any one of claims 1 to 6, wherein the height of the biasing spring is 120% to 125% of the height of the shape memory alloy spring. The reproducible fuse according to any one of claims 1 to 6, wherein the shape memory alloy spring comprises nickel (Ni) and titanium (Ti). The reproducible fuse of claim 9, wherein the shape memory alloy spring comprises at least one of cobalt (Co), molybdenum (Mo), tungsten (W), and chromium (Cr). The reproducible fuse according to any one of claims 1 to 6, wherein the bias spring comprises SUS stainless steel, and the stainless steel is coated with Ni, Cu, Ag, Au, and Sn. At least either.