CN108140508B

CN108140508B - Fuse element

Info

Publication number: CN108140508B
Application number: CN201680060187.1A
Authority: CN
Inventors: 川津雅巳
Original assignee: Dexerials Corp
Current assignee: Dexerials Corp
Priority date: 2015-10-27
Filing date: 2016-10-25
Publication date: 2020-01-17
Anticipated expiration: 2036-10-25
Also published as: JP2017084591A; TW201729230A; KR102032665B1; CN108140508A; JP6739922B2; KR20180050736A; WO2017073539A1; TWI701693B

Abstract

A small fuse element which can handle a large current with a simple structure is provided. The fuse element 1 includes: an insulating substrate 2; a 1 st electrode 3 and a 2 nd electrode 4 disposed on a surface 2a of the insulating substrate 2; and a conductor 6 connected to the 1 st electrode 3 and the 2 nd electrode 4 via the low-melting-point metal 5, respectively, and having a melting point higher than that of the low-melting-point metal 5, wherein the conductor 6 is moved to be separated from at least one of the 1 st electrode 3 and the 2 nd electrode 4 by melting of the low-melting-point metal 5, thereby cutting off an electrical path between the 1 st electrode 3 and the 2 nd electrode 4.

Description

Fuse element

Technical Field

The present invention relates to a fuse element that is mounted on a current path and blocks the current path when a predetermined current flows. This application claims priority based on Japanese application No. 2015-211340, filed on 27.10.2015, which is incorporated by reference into this application.

Background

Conventionally, a fuse element incorporating a fuse unit (fuse element) that melts and breaks a current path due to self-heating when a current exceeding a rated value flows has been used. As the fuse element, for example, a fuse element of an electrode clamp type in which solder is sealed in a glass tube, a patch fuse in which an Ag electrode is printed on a surface of a ceramic substrate, a screw-fixing type in which a copper electrode is partially thinned and incorporated in a plastic case, or an insertion type fuse element is often used.

Since the conventional fuse element described above is difficult to perform surface mounting by reflow and the efficiency of component mounting is low, a surface-mounted fuse element such as that described in patent document 1 has been developed in recent years.

The surface-mount fuse element described in patent document 1 has a function of cutting off a fuse element due to an overcurrent as in a general current fuse, and has an advantage that the fuse element can be used as a switch by blowing the fuse element at a desired timing based on control on the electric circuit side by a method of heating the fuse element by energizing a heater with an external circuit.

Such a fuse element is mainly used as a protection element for overcharge or overcurrent of a battery pack using a lithium ion secondary battery. Lithium ion secondary batteries are used in mobile devices such as notebook personal computers, cellular phones, and smart phones, and have been recently used in electric tools, electric bicycles, electric motorcycles (bikes), electric automobiles, and the like. Therefore, the capacity of the battery pack increases, and the rated current required for the fuse element also increases year by year.

In the fuse unit of patent document 1, in order to cope with a large current, a unit in which a low melting point metal layer and a high melting point metal layer are laminated is used, and the low melting point metal layer corrodes the high melting point metal layer to increase the fusing speed, and the quick-break property is secured regardless of the large current.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open No. 2013-229293.

Disclosure of Invention

Problems to be solved by the invention

With regard to the conventional fuse element, such a problem has been pointed out: when the current rating is increased to cope with a large current, if the fuse unit is increased in size and the current rating is increased, the volume of the fuse unit to be blown is increased, and quick-break performance is poor.

To describe in more detail, since it is necessary to reduce the resistance value of the fuse element in order to increase the rated current, the cross-sectional area of the fuse unit is increased, and the size of the entire fuse element is also increased.

Further, as a drawback of increasing the cross-sectional area of the fuse element, the volume of the melting element melted by heat generation of a heater or the like also increases, the melting element cannot be accommodated in the electrode, and there is a possibility that a failure in circuit disconnection may occur.

In order to accommodate a melting unit melted by heat generation of a heater or the like in an electrode, the size of the electrode can be increased, and the size of the fuse element is increased.

Further, the fuse element described in patent document 1 has a problem that: the fuse unit is miniaturized and quick-break property is ensured by laminating the low-melting-point metal layer and the high-melting-point metal layer, but the manufacturing process is complicated and the fuse unit is difficult to manufacture at low cost because a special structure is adopted in the fuse unit.

Accordingly, an object of the present invention is to provide a small fuse element that can handle a large current with a simple structure.

Means for solving the problems

In order to solve the above problem, a fuse element according to the present invention includes: an insulating substrate; a plurality of electrodes disposed on the insulating substrate; and a conductor connected to the plurality of electrodes through the low-melting-point metal and having a melting point higher than that of the low-melting-point metal, wherein the conductor is moved to be separated from at least one of the plurality of electrodes by melting of the low-melting-point metal, thereby cutting off an electrical path between any of the electrodes.

Effects of the invention

According to the present invention, since the circuit of the fuse element is cut not by the fusion of the fuse element, and when the low melting point metal connecting the electrode and the conductor is fused, the conductor is moved by the surface tension of the fused low melting point metal to cut the electrical path between the electrodes, the conductor corresponding to the fuse element does not need to be fused, and a low-cost conductor having a high melting point and a simple structure is used, thereby achieving the miniaturization of the fuse element.

Drawings

Fig. 1 is a plan view showing a 1 st example of a fuse element to which the present invention is applied.

Fig. 2 is a cross-sectional view showing a 1 st example of a fuse element to which the present invention is applied.

Fig. 3 is a plan view showing a 1 st example of a fuse element to which the present invention is applied, and shows a state after the fuse element is operated.

Fig. 4 is a circuit diagram illustrating a circuit configuration of example 1 of a fuse element to which the present invention is applied, fig. 4 (a) shows a state before an operation of the fuse element, and fig. 4 (B) shows a state after the operation of the fuse element.

Fig. 5 is a cross-sectional view showing a modification of the fuse element to which the present invention is applied.

Fig. 6 is a cross-sectional view showing another modification of the fuse element to which the present invention is applied.

Fig. 7 is a cross-sectional view showing another modification of the fuse element to which the present invention is applied.

Fig. 8 is a plan view showing another modification of the fuse element to which the present invention is applied.

Fig. 9 is a plan view showing another modification of the fuse element to which the present invention is applied.

Fig. 10 is a plan view showing a 2 nd example of a fuse element to which the present invention is applied.

Fig. 11 is a cross-sectional view showing a 2 nd example of a fuse element to which the present invention is applied.

Fig. 12 is a plan view showing a 2 nd example of a fuse element to which the present invention is applied, and shows a state after the fuse element is operated.

Fig. 13 is a circuit diagram illustrating a circuit configuration of example 2 of a fuse element to which the present invention is applied, fig. 13 (a) shows a state before an operation of the fuse element, and fig. 13 (B) shows a state after the operation of the fuse element.

Fig. 14 is a cross-sectional view showing a modification of the fuse element to which the present invention is applied.

Fig. 15 is a cross-sectional view showing another modification of the fuse element to which the present invention is applied.

Fig. 16 is a cross-sectional view showing another modification of the fuse element to which the present invention is applied.

Fig. 17 is a plan view showing another modification of the fuse element to which the present invention is applied.

Fig. 18 is a plan view showing another modification of the fuse element to which the present invention is applied.

Fig. 19 is a plan view showing another modification of the fuse element to which the present invention is applied.

Fig. 20 is a plan view showing a 3 rd example of a fuse element to which the present invention is applied.

FIG. 21 is a sectional view showing a 3 rd example of a fuse element to which the present invention is applied.

Fig. 22 is a plan view showing a 3 rd example of a fuse element to which the present invention is applied, and shows a state after the fuse element is operated.

Fig. 23 is a circuit diagram illustrating a circuit configuration of example 3 of a fuse element to which the present invention is applied, fig. 23 (a) shows a state before an operation of the fuse element, and fig. 23 (B) shows a state after the operation of the fuse element.

Fig. 24 is a cross-sectional view showing a modification of the fuse element to which the present invention is applied.

Fig. 25 is a plan view showing another modification of the fuse element to which the present invention is applied.

Fig. 26 is a cross-sectional view showing another modification of the fuse element to which the present invention is applied.

Fig. 27 is a plan view showing another modification of the fuse element to which the present invention is applied.

Fig. 28 is a view showing a modification of a conductor provided in a fuse element to which the present invention is applied.

Detailed Description

Hereinafter, a fuse element to which the present invention is applied will be described in detail with reference to the drawings. The present invention is not limited to the following embodiments, and various modifications can be made without departing from the scope of the present invention. The drawings are schematic, and the proportions of the dimensions and the like may be different from those in reality. Specific dimensions and the like should be determined in consideration of the following description. In addition, it is obvious that the drawings include portions having different dimensional relationships or ratios from each other.

[ embodiment 1]

[ fuse element ]

As shown in fig. 1 to 3, a fuse element 1 according to the present invention includes: an insulating substrate 2; a plurality of electrodes 3 and 4 (hereinafter, referred to as a 1 st electrode 3 and a 2 nd electrode 4) disposed on the insulating substrate 2; and a conductor 6 connected to the 1 st electrode 3 and the 2 nd electrode 4 via a low-melting-point metal 5 and having a melting point higher than that of the low-melting-point metal 5.

Fig. 1 and 3 are plan views of the conductor 6 seen through the fuse element 1 from above, and the conductor 6 is shown by a broken line. Fig. 2 is a sectional view taken along line a-a' of fig. 1.

The insulating substrate 2 is substantially rectangular, and is formed in a square shape by an insulating member such as alumina, glass ceramic, mullite, or zirconia. The insulating substrate 2 may be a material for a printed wiring substrate such as a glass epoxy substrate or a phenol substrate.

The 1 st electrode 3 and the 2 nd electrode 4 are formed on opposite ends of the insulating substrate 2. The 1 st electrode 3 and the 2 nd electrode 4 are each formed by a conductive pattern such as Cu or Ag wiring, and in the case of a wiring material such as Cu which is easily oxidized, a protective layer such as a Ni/Au plating layer or a Sn plating layer is appropriately provided on the surface as a measure against oxidation. The 1 st electrode 3 and the 2 nd electrode 4 extend from the front surface 2a to the back surface 2b of the insulating substrate 2 through the side surfaces. The fuse element 1 is surface-mounted on a current path of a circuit board, not shown, via a 1 st electrode 3 and a 2 nd electrode 4 formed on the rear surface 2 b.

The low melting point metal 5 is a conductive connecting material for connecting the conductor 6 by mounting it on the 1 st electrode 3 and the 2 nd electrode 4, and for example, a metal containing Sn as a main component can be used as a solder paste. Is a material commonly referred to as "lead-free solder. The melting point of the low-melting metal 5 is set to be about the temperature of the reflow furnace.

The conductor 6 is made of a conductor material having a higher melting point and a lower resistance than the low melting point metal 5, and is disposed so as to overlap the 1 st electrode 3 and the 2 nd electrode 4 as shown in fig. 1 to 3, and is a substantially rectangular and plate-like member. The conductor 6 is not limited to a rectangular or plate shape, but this shape is adopted in the present embodiment from the viewpoint of ease of processing.

Specifically, the conductor 6 is preferably a high-melting-point and low-resistance metal material, and Ag, Au, Al, Cu alloy, or the like can be used. The conductor 6 is preferably made of Cu or a Cu alloy which is inexpensive, does not undergo natural oxidation, and is easily connected to the conductor by a low melting point metal. The conductor 6 forms a current path between the 1 st electrode 3 and the 2 nd electrode 4, and is not fused by self-heating (joule heat) of a current exceeding a rated value. However, the electric conductor 6 does not obviously prevent the fusing by self-heating.

The conductive body 6 has a high melting point that does not melt even when mounted on the insulating substrate 2 by a reflow furnace. This is because it is difficult to mount the conductor 6 when melted at the reflow temperature.

The fuse element 1 is small in size and has a high rating, and for example, the resistance value can be increased to 0.5 to 1 m.OMEGA. and 50 to 60A rating while the size of the fuse element as the insulating substrate 2 is reduced to about 3 to 4mm × 5 to 6 mm. It is apparent that the present invention can be applied to fuse elements having all sizes, resistance values, and current ratings.

[ operation of fuse element ]

In the fuse element 1, the conductor 6 slides on the surface 2a of the insulating substrate 2 until it is separated from at least one of the 1 st electrode 3 and the 2 nd electrode 4 by melting of the low melting point metal 5, and the current passing path between the 1 st electrode 3 and the 2 nd electrode 4 can be cut off.

The conductor 6 is connected to the 1 st electrode 3 and the 2 nd electrode 4 with the low melting point metal 5 at different connection areas. Therefore, the conductor 6 slides on the surface 2a of the insulating substrate 2 so as to be drawn to the larger connection area of the 1 st electrode 3 or the 2 nd electrode 4 by the different tensions due to the melting of the low melting point metal 5.

Specifically, as shown in fig. 1 to 3, the fuse element 1 is configured such that the connection area of the low-melting-point metal 5b on the 2 nd electrode 4 to the conductor 6 is larger than the connection area of the low-melting-point metal 5a on the 1 st electrode 3 to the conductor 6. Therefore, the conductor 6 is pulled toward the 2 nd electrode 4 side in the arrow direction in the figure by the melting of the low melting point metal 5, slides on the surface 2a of the insulating substrate 2, and is held on the 2 nd electrode 4 by the low melting point metal 5b as shown in fig. 3.

As shown in fig. 1 and 2, the conductor 6 is connected and held to the 1 st electrode 3 and the 2 nd electrode 4 via the low

melting point metals

5a and 5b in a state shifted (offset) toward the 2 nd electrode 4 side from the 1 st electrode 3.

Specifically, as shown in fig. 1, the length of the conductor 6 at the portion where the 1 st electrode 3 and the conductor 6 overlap is L₁And the length L of the 2 nd electrode 4 of the portion where the 2 nd electrode 4 does not overlap with the conductor 6₂Then to be L₁＜L₂The second electrode is assembled in a state of being shifted toward the 2 nd electrode 4.

This is because the length L of the conductor 6 to be fitted to the contact portion of the 1 st electrode 3 cannot be secured if necessary₁The above movement does not completely cut off the electrical connection between the conductor 6 and the 1 st electrode 3. In other words, the amount of movement of the conductor 6 by the slide conveyance depends on the length L of the 2 nd electrode 4 that does not overlap with the conductor 6₂Therefore, it can be said that L needs to be adjusted₂Is ensured to be L₁The above.

Next, the operation of the fuse element 1 will be described with reference to a circuit diagram. As shown in fig. 4 (a), in the fuse element 1, the conductor 6 is connected to the 1 st electrode 3 and the 2 nd electrode 4, and conduction is established between the 1 st electrode 3 and the 2 nd electrode 4. As shown in fig. 4 (B), when the low melting point metal 5 melts due to heat from the outside, the fuse element 1 slides the conductor 6 toward the 2 nd electrode 4 side, separates the conductor 6 from the 1 st electrode 3, and cuts off the conduction between the 1 st electrode 3 and the 2 nd electrode 4.

[ modification 1]

Next, modified example 1 will be described as another example of embodiment 1. The same portions as those of the fuse element 1 described above are denoted by the same reference numerals, and the description thereof is omitted, and the differences will be specifically described.

As shown in fig. 5, the fuse element 1 according to modification 1 includes a support member 7 for supporting the conductor 6 between the 1 st electrode 3 and the 2 nd electrode 4 on the surface 2a of the insulating substrate 2. Fig. 5 is a cross-sectional view corresponding to line a-a' in fig. 1. The support member 7 is disposed between the 1 st electrode 3 and the 2 nd electrode 4, and is preferably made of an insulating material or coated with an insulating material (coating) in order to avoid short-circuiting between the electrodes.

The support member 7 supports the conductor 6 so as to be slidable and is fixed to the surface 2a of the insulating substrate 2. That is, the support member 7 and the conductor 6 are not fixed, and the support member 7 is formed with a shape or coating such that the conductor 6 slips.

When the low melting point metal 5 melts, the conductor 6 is supported by the support member 7 and can smoothly slide toward the 2 nd electrode 4 side in the horizontal direction. That is, in the middle of the sliding movement of the low melting point metal 5 toward the 2 nd electrode 4 side, the conductor 6 is in a state in which the low melting point metal 5b on the 2 nd electrode 4 is cantilevered, and therefore it is conceivable that the conductor 6 is inclined on the surface 2a of the insulating substrate 2 and cannot perform the sliding movement properly. Therefore, the support member 7 can be supported to be able to appropriately perform sliding movement by maintaining the horizontal state of the conductor 6.

[ modification 2]

Next, modification 2 will be described as another example of embodiment 1. The same portions as those of the fuse element 1 described above are denoted by the same reference numerals, and the description thereof is omitted, and the differences will be specifically described.

As shown in fig. 6, the fuse element 1 according to modification 2 includes a cover member 8 for protecting the 1 st electrode 3, the 2 nd electrode 4, the low melting point metal 5, the conductor 6, and the like on the surface 2a of the insulating substrate 2. Fig. 6 is a cross-sectional view corresponding to line a-a' in fig. 1.

The cover member 8 is provided with a movement regulation portion 8a for regulating the movable region of the conductor 6, and has a stopper function for preventing the conductor 6 from moving in a direction other than the predetermined direction. The cover member 8 can be formed of an insulating member such as a thermoplastic, ceramic, or glass epoxy substrate.

In the cover member 8, a movement regulation portion 8a extends to the same height as the conductor 6 on the surface 2a of the insulating substrate 2, and the movement regulation portion 8a is provided at a position where a predetermined gap is maintained from the initial position of the conductor 6 to the 1 st electrode 3 side. That is, the movement regulating portion 8a and the conductor 6 do not contact each other at the initial position of the conductor 6, but when the conductor 6 moves toward the 1 st electrode 3 side due to impact or the like in a state where the low melting point metal 5 is melted, the movement regulating portion 8a and the conductor 6 contact each other, and the conductor 6 does not slide in an incorrect direction.

Even in a state where the movement of the conductor 6 is regulated by the movement regulation portion 8a, if the connection area of the conductor 6 on the low melting point metal 5b side is large, the conductor 6 is pulled toward the 2 nd electrode 4 side due to the tension of the low melting point metal 5b at all times, and the conductor 6 also slides toward the 2 nd electrode 4 side.

Therefore, the movement regulating portion 8a regulates the movement of the conductor 6 in the opposite direction, thereby preventing the conductor 6 from moving to the 1 st electrode 3 side and reliably moving to the 2 nd electrode 4 side by sliding.

[ modification 3]

Next, modified example 3 will be described as another example of embodiment 1. The same portions as those of the fuse element 1 described above are denoted by the same reference numerals, and the description thereof is omitted, and the differences will be specifically described.

As shown in fig. 7, the fuse element 1 according to modification 3 includes a movement regulation member 9 for regulating movement of the conductor 6 on the surface 2a of the insulating substrate 2. Fig. 7 is a sectional view corresponding to line a-a' in fig. 1.

The movement regulating member 9 is fixed to the surface 2a of the insulating substrate 2, and in this configuration, the member fixed to the 1 st electrode 3 in particular has a braking function of preventing the conductor 6 from moving in a direction other than the predetermined direction. The movement regulating member 9 can be made of, for example, an insulator, but does not cause a problem such as a short circuit in a circuit structure, and therefore, when it is integrally manufactured with the 1 st electrode 3, the same metal material as that of the 1 st electrode 3 can be used.

The movement regulation member 9 extends to the same height as the conductor 6 on the surface 2a of the insulating substrate 2, and the movement regulation member 9 is provided at a position where a predetermined gap is maintained from the initial position of the conductor 6 toward the 1 st electrode 3 side. That is, the movement regulating member 9 and the conductor 6 do not contact each other at the initial position of the conductor 6, but when the conductor 6 moves toward the 1 st electrode 3 side due to impact or the like in a state where the low melting point metal 5 is melted, the movement regulating member 9 and the conductor 6 contact each other, and the conductor 6 does not slide in an incorrect direction.

Even in a state where the movement regulating member 9 regulates the movement of the conductor 6, if the connection area of the conductor 6 on the low melting point metal 5b side is large, the conductor 6 is pulled toward the 2 nd electrode 4 side due to the tension of the low melting point metal 5b at all times, and the conductor 6 also slides toward the 2 nd electrode 4 side.

Therefore, the movement regulating member 9 regulates the movement of the conductor 6 in the opposite direction, thereby preventing the conductor 6 from moving to the 1 st electrode 3 side and reliably moving to the 2 nd electrode 4 side.

[ modification 4]

Next, modified example 4 will be described as another example of embodiment 1. The same portions as those of the fuse element 1 described above are denoted by the same reference numerals, and the description thereof is omitted, and the differences will be specifically described.

As shown in fig. 8, the fuse element 1 according to modification 4 includes a guide portion 10 for guiding the movement of the conductor 6 on the surface 2a of the insulating substrate 2. Fig. 8 is a plan view of the conductive body 6 as seen from above the fuse element 1, and the conductive body 6 is shown by a broken line.

The guide member 10 is fixed to the surface 2a of the insulating substrate 2, and has a guide function in a moving direction for moving the conductor 6 in a predetermined direction. The guide member 10 is preferably formed of two parallel members extending from the 1 st electrode 3 side to the 2 nd electrode 4 side, and an insulator such as a resin material is used so that short circuit between both electrodes does not occur.

The guide member 10 extends to the same height as the conductor 6 on the surface 2a of the insulating substrate 2, and the guide member 10 is provided at a position serving as a guide rail defining a movement direction from a side surface in a range where the conductor 6 moves from the initial position to the 2 nd electrode 4 side. That is, the guide member 10 and the conductor 6 are in contact with each other on the side from the initial position of the conductor 6, and the conductor 6 is not slid in the wrong direction until the conductor 6 moves toward the 2 nd electrode 4 side in a state where the low melting point metal 5 is melted.

Therefore, the guide member 10 regulates the movement of the conductor 6 in the direction of inclination or in the direction of inclination, so that the conductor 6 can be reliably slid toward the 2 nd electrode 4 side.

[ modification 5]

Next, modification 5 will be described as another example of embodiment 1. The same portions as those of the fuse element 1 described above are denoted by the same reference numerals, and the description thereof is omitted, and the differences will be specifically described.

As shown in fig. 9, the fuse element 1 according to modification 5 is configured such that the conductor 6 has a trapezoidal shape. Fig. 9 is a plan view of the conductive body 6 as seen from above the fuse element 1, and the conductive body 6 is shown by a broken line.

The conductor 6 has a rectangular shape in the other example, but has a trapezoidal structure having an upper bottom whose short side is the 1 st electrode 3 side and a lower bottom whose long side is the 2 nd electrode 4 side. That is, the area of the conductor 6 on the 1 st electrode 3 side becomes smaller, while the area on the 2 nd electrode 4 side becomes larger. Therefore, the connection area of the conductor 6 and the 1 st electrode 3 and the 2 nd electrode 4 by the low melting point metal 5 is larger on the 2 nd electrode 4 side than on the 1 st electrode 3 side, and the tensile force by the molten low melting point metal 5b becomes large.

Therefore, the fuse element 1 can reliably slide the trapezoidal conductor 6 toward the 2 nd electrode 4 side.

The modifications of embodiment 1 described above can be used in any combination, and it is obvious that the modifications can be used in appropriate combinations in order to obtain the effects of the combination. That is, it can be said that by applying all the modifications, the electric conductor 6 can be reliably moved when the low melting point metal 5 is melted, and the electric connection between the 1 st electrode 3 and the 2 nd electrode 4 can be reliably cut.

[ 2 nd embodiment ]

[ fuse element ]

Another embodiment of the fuse element 1 according to the present invention will be described. Note that the same reference numerals are given to the components having the same functions as those described in embodiment 1, and the description thereof is omitted.

As shown in fig. 10 to 12, the fuse element 1 according to the present invention includes: an insulating substrate 2; a plurality of

electrodes

3, 4, and 11 (hereinafter, referred to as a 1 st electrode 3, a 2 nd electrode 4, and a 3 rd electrode 11) disposed on the insulating substrate 2; a conductor 6 connected to the 1 st electrode 3, the 2 nd electrode 4, and the 3 rd electrode 11 via a low-melting-point metal 5, respectively, and having a melting point higher than that of the low-melting-point metal 5; and a heater 12 disposed below the 2 nd electrode 4.

Fig. 10 and 12 are plan views of the conductor 6 seen through and from above the fuse element 1, and the conductor 6 is shown by a broken line. Fig. 11 is a sectional view taken along line B-B' of fig. 10.

On one end of the insulating substrate 2, a 1 st electrode 3 and a 3 rd electrode 11 are formed with a predetermined distance therebetween. Further, a 2 nd electrode 4 is formed on the other end portion of the insulating substrate 2, particularly, on an end portion adjacent to the one end portion on which the 1 st electrode 3 and the 3 rd electrode 11 are provided. The 2 nd electrode 4 extends so as to face the 1 st electrode 3 and the 3 rd electrode 11, and is disposed on the surface 2a of the insulating substrate 2 so that the 1 st electrode 3 and the 3 rd electrode 11 face the 2 nd electrode 4.

The 1 st electrode 3, the 2 nd electrode 4, and the 3 rd electrode 11 are each formed by a conductive pattern such as Cu or Ag wiring, and in the case of wiring materials such as Cu which are easily oxidized, a protective layer such as Ni/Au plating or Sn plating is appropriately provided on the surface as a measure against oxidation. The 1 st electrode 3, the 2 nd electrode 4, and the 3 rd electrode 11 extend from the front surface 2a to the back surface 2b of the insulating substrate 2 through the side surfaces. The fuse element 1 is surface-mounted on a current path of a circuit board, not shown, via a 1 st electrode 3, a 2 nd electrode 4, and a 3 rd electrode 11 formed on the rear surface 2 b.

The low melting point metal 5 is a conductive connecting material for connecting the conductor 6 by mounting it on the 1 st electrode 3, the 2 nd electrode 4, and the 3 rd electrode 11, and for example, a metal containing Sn as a main component can be used as a solder paste. Is a material commonly referred to as "lead-free solder. The melting point of the low-melting metal 5 is set to be about the temperature of the reflow furnace.

The conductor 6 is made of a conductor material having a higher melting point and a lower resistance than the low melting point metal 5, and is disposed so as to overlap the 1 st electrode 3, the 2 nd electrode 4, and the 3 rd electrode 11 as shown in fig. 10 to 11, and is a substantially rectangular and plate-shaped member. The conductor 6 is not limited to a rectangular or plate shape, but this shape is adopted in the present embodiment from the viewpoint of ease of processing.

Specifically, the conductor 6 is preferably a high-melting-point and low-resistance metal material, and Ag, Au, Al, Cu alloy, or the like can be used. The conductor 6 is preferably made of Cu or a Cu alloy which is inexpensive, does not undergo natural oxidation, and is easily connected to the conductor by a low melting point metal. The conductor 6 forms a current path between the 1 st electrode 3 and the 3 rd electrode 11, and is not fused by self-heating (joule heat) of a current exceeding a rated value. However, the electric conductor 6 does not obviously prevent the fusing by self-heating.

The heater 12 is a resistance member that generates heat for melting the low melting point metal 5, and is electrically and thermally connected to the 2 nd electrode 4, although the description will be given with reference to a circuit diagram to be described later. When a rated current flows through the electric circuit, heat is applied to melt the low melting point metal 5.

[ operation of fuse element ]

In the fuse element 1, the conductor 6 slides on the surface 2a of the insulating substrate 2 by melting of the low melting point metal 5 until the conductor is separated from the 1 st electrode 3 and the 3 rd electrode 11 among the 1 st electrode 3, the 2 nd electrode 4, and the 3 rd electrode 11, and the current path between the 1 st electrode 3 and the 3 rd electrode 11 can be cut off.

The conductor 6 is connected to the 1 st electrode 3 and the 3 rd electrode 11 in combination and the 2 nd electrode 4 by the low melting point metal 5 at different connection areas. Therefore, the conductor 6 is drawn by the different tensions to the combination of the 1 st electrode 3 and the 3 rd electrode 11 and the larger connection area of the 2 nd electrode 4 by the melting of the low melting point metal 5, and slides on the surface 2a of the insulating substrate 2.

Specifically, as shown in fig. 10 to 12, in the fuse element 1, the connection area of the low-melting-point metal 5b on the 2 nd electrode 4 to the conductor 6 is made larger than the sum of the connection area of the low-melting-point metal 5a on the 1 st electrode 3 to the conductor 6 and the connection area of the low-melting-point metal 5c on the 3 rd electrode 11 to the conductor 6. Therefore, the conductor 6 is drawn toward the 2 nd electrode 4 side in the arrow direction in the figure by the melting of the low melting point metal 5b, slides on the surface 2a of the insulating substrate 2, and is held on the 2 nd electrode 4 by the low melting point metal 5b as shown in fig. 12.

As shown in fig. 10 and 11, the conductor 6 is connected and held to the 1 st electrode 3, the 2 nd electrode 4, and the 3 rd electrode 11 via the low

melting point metals

5a, 5b, and 5c in a state shifted toward the 2 nd electrode 4 side from the 1 st electrode 3 and the 3 rd electrode 11, respectively.

Specifically, as shown in fig. 10, the length of the conductor 6 is L at the portion where the 1 st electrode 3 and the 3 rd electrode 11 overlap with the conductor 6₁And the length L of the 2 nd electrode 4 of the portion where the 2 nd electrode 4 does not overlap with the conductor 6₂Then to be L₁＜L₂The second electrode is assembled in a state of being shifted toward the 2 nd electrode 4.

This is because the length L of the conductor 6 corresponding to the contact portion between the 1 st electrode 3 and the 3 rd electrode 11 cannot be secured if necessary₁The above movement does not completely cut off the electrical connection between the conductor 6 and the 1 st electrode 3 and the 3 rd electrode 11. In other words, the amount of movement of the conductor 6 by the slide conveyance depends on the length L of the 2 nd electrode 4 that does not overlap with the conductor 6₂Therefore, it can be said that L needs to be adjusted₂Is ensured to be L₁The above.

Next, the operation of the fuse element 1 will be described with reference to a circuit diagram. As shown in fig. 13 (a), in the fuse element 1, the conductor 6 is connected to the 1 st electrode 3, the 2 nd electrode 4, and the 3 rd electrode 11, and the 1 st electrode 3, the 2 nd electrode 4, and the 3 rd electrode 11 are electrically connected to each other. As shown in fig. 13 (B), when the low melting point metal 5 is melted by heat from the heater 12, the fuse element 1 slides the conductor 6 toward the 2 nd electrode 4 side, separates the conductor 6 from the 1 st electrode 3 and the 3 rd electrode 11, and cuts off the conduction of the 1 st electrode 3 and the 3 rd electrode 11. It is clear that the conduction between the 1 st electrode 3 and the 2 nd electrode 4, and between the 3 rd electrode 11 and the 2 nd electrode 4 is cut off. This also cancels the energization of the heater 12, and thus the heater 12 stops generating heat.

[ modification 6]

Next, modified example 6 will be described as another example of embodiment 2. The same portions as those of the fuse element 1 described above are denoted by the same reference numerals, and the description thereof is omitted, and the differences will be specifically described.

As shown in fig. 14, the fuse element 1 according to the modification 6 includes a support member 7 for supporting the conductor 6 between the 1 st and 3

rd electrodes

3 and 11 and the 2 nd electrode 4 on the surface 2a of the insulating substrate 2. Fig. 14 is a sectional view corresponding to line B-B' in fig. 10. The support member 7 is disposed between the 1 st and 3

rd electrodes

3 and 11 and the 2 nd electrode 4, and is preferably made of an insulating material or coated with an insulating material in order to avoid short-circuiting between the electrodes.

[ modification 7]

Next, modified example 7 will be described as another example of embodiment 2. The same portions as those of the fuse element 1 described above are denoted by the same reference numerals, and the description thereof is omitted, and the differences will be specifically described.

As shown in fig. 15, the fuse element 1 according to modification 7 includes a cover member 8 for protecting the 1 st electrode 3, the 2 nd electrode 4, the 3 rd electrode 11, the low melting point metal 5, the conductor 6, and the like on the surface 2a of the insulating substrate 2. Fig. 15 is a sectional view corresponding to line B-B' in fig. 10.

The cover member 8 is provided with a movement regulation portion 8a for regulating the movable region of the conductor 6, and has a braking function for preventing the conductor 6 from moving in a direction other than the predetermined direction. The cover member 8 can be formed of an insulating member such as a thermoplastic, ceramic, or glass epoxy substrate.

In the cover member 8, a movement regulation portion 8a extends to the same height as the conductor 6 on the surface 2a of the insulating substrate 2, and the movement regulation portion 8a is provided at a position where a predetermined gap is maintained from the initial position of the conductor 6 to the 1 st electrode 3 and the 3 rd electrode 11 side. That is, the movement regulating portion 8a and the conductor 6 do not contact each other at the initial position of the conductor 6, but when the conductor 6 moves toward the 1 st electrode 3 and the 3 rd electrode 11 due to impact or the like in a state where the low melting point metal 5 is melted, the movement regulating portion 8a and the conductor 6 contact each other, and the conductor 6 does not slide in an incorrect direction.

Even in a state where the movement of the conductor 6 is regulated by the movement regulation section 8a, if the connection area of the conductor 6 on the low melting point metal 5b side is large, the conductor 6 is pulled toward the 2 nd electrode 4 side due to the tension of the low melting point metal 5b at all times, and the conductor 6 is also slidingly moved toward the 2 nd electrode 4 side.

Therefore, the movement regulating portion 8a regulates the movement of the conductor 6 in the opposite direction, thereby preventing the conductor 6 from moving to the 1 st electrode 3 and the 3 rd electrode 11 side and reliably moving to the 2 nd electrode 4 side by sliding.

[ modification 8]

Next, modified example 8 will be described as another example of embodiment 2. The same portions as those of the fuse element 1 described above are denoted by the same reference numerals, and the description thereof is omitted, and the differences will be specifically described.

As shown in fig. 16, the fuse element 1 according to the modification 8 includes a movement regulation member 9 for regulating the movement of the conductor 6 on the surface 2a of the insulating substrate 2. Fig. 16 is a sectional view corresponding to line B-B' in fig. 10.

The movement regulating member 9 is fixed to the surface 2a of the insulating substrate 2, and in the present configuration, particularly, the members fixed to the 1 st electrode 3 and the 3 rd electrode 11 have a braking function of preventing the conductor 6 from moving in a direction other than the predetermined direction. Since the movement regulation member 9 is provided so as to overlap the 1 st electrode 3 with the 3 rd electrode 11, an insulator such as a resin material is preferably used in order to prevent a short circuit in the circuit.

The movement regulation member 9 extends to the same height as the conductor 6 on the surface 2a of the insulating substrate 2, and the movement regulation member 9 is provided at a position where a predetermined gap is maintained from the initial position of the conductor 6 to the 1 st electrode 3 and the 3 rd electrode 11 side. That is, the movement regulating member 9 and the conductor 6 do not contact each other at the initial position of the conductor 6, but when the conductor 6 moves toward the 1 st electrode 3 and the 3 rd electrode 11 due to impact or the like in a state where the low melting point metal 5 is melted, the movement regulating member 9 and the conductor 6 contact each other, and the conductor 6 does not slide in an incorrect direction.

Therefore, the movement regulating member 9 regulates the movement of the conductor 6 in the opposite direction, thereby preventing the conductor 6 from moving to the 1 st electrode 3 and the 3 rd electrode 11 side and reliably sliding toward the 2 nd electrode 4 side.

[ modification 9]

Next, modified example 9 will be described as another example of embodiment 2. The same portions as those of the fuse element 1 described above are denoted by the same reference numerals, and the description thereof is omitted, and the differences will be specifically described.

As shown in fig. 17, the fuse element 1 according to modification 9 includes a guide portion 10 for guiding the movement of the conductor 6 on the surface 2a of the insulating substrate 2. Fig. 17 is a plan view of the conductive body 6 as seen from above the fuse element 1, and the conductive body 6 is shown by a broken line.

The guide member 10 is fixed to the surface 2a of the insulating substrate 2, and has a guide function in a moving direction for moving the conductor 6 in a predetermined direction. The guide member 10 is preferably formed of two parallel members extending from the 1 st electrode 3 and the 3 rd electrode 11 side to the 2 nd electrode 4 side, and an insulator such as a resin material is used so that short circuit between both electrodes does not occur.

Therefore, the guide member 10 can reliably slide toward the 2 nd electrode 4 side by defining the conductor 6 to be inclined or to move in an inclined direction.

[ modification 10]

Next, modified example 10 will be described as another example of embodiment 2. The same portions as those of the fuse element 1 described above are denoted by the same reference numerals, and the description thereof is omitted, and the differences will be specifically described.

As shown in fig. 18, the fuse element 1 according to modification 10 is configured such that the conductor 6 has a trapezoidal shape. Fig. 18 is a plan view of the conductive body 6 as seen from above the fuse element 1, and the conductive body 6 is shown by a broken line.

The conductor 6 has a rectangular shape in the other example, but has a trapezoidal structure having an upper base whose short side is the 1 st electrode 3 and the 3 rd electrode 11 side and a lower base whose long side is the 2 nd electrode 4 side. That is, the area of the conductor 6 on the 1 st electrode 3 and the 3 rd electrode 11 side becomes smaller, and the area on the 2 nd electrode 4 side becomes larger. Therefore, the connection area formed by the conductor 6, the 1 st electrode 3, the 2 nd electrode 4, the 3 rd electrode 11 and the low melting point metal 5 is larger on the 2 nd electrode 4 side than on the 1 st electrode 3 and the 3 rd electrode 11 side, and the tensile force by the molten low melting point metal 5b is increased.

[ modification 11]

Next, modified example 11 will be described as another example of embodiment 2. The same portions as those of the fuse element 1 described above are denoted by the same reference numerals, and the description thereof is omitted, and the differences will be specifically described.

As shown in fig. 19, the fuse element 1 according to modification 11 is configured such that the conductor 6 has a shape having two convex portions. Fig. 19 is a plan view of the fuse element 1 viewed from above through the conductor 6, and the conductor 6 is shown by a broken line.

The conductor 6 has a rectangular shape in the other example described above, but has a structure in which two convex portions 6a and 6b are provided in a trapezoidal shape having an upper bottom whose short side is the 1 st electrode 3 side and a trapezoidal shape having an upper bottom whose short side is the 3 rd electrode 11 side. That is, the area of the conductor 6 on the 1 st electrode 3 and the 3 rd electrode 11 side becomes smaller, and the area on the 2 nd electrode 4 side becomes larger. Therefore, the connection area formed by the conductor 6, the 1 st electrode 3, the 2 nd electrode 4, the 3 rd electrode 11 and the low melting point metal 5 is larger on the 2 nd electrode 4 side than on the 1 st electrode 3 and the 3 rd electrode 11 side, and the tensile force by the molten low melting point metal 5b is increased.

Modification 11 can also be said to be a shape in which a portion not contributing to current conduction is cut out so as to reduce the size of conductor 6 as compared with modification 10. The conductor 6 is easily moved by downsizing the conductor 6.

The modifications in embodiment 2 described above can be used in any combination, and it is obvious that the modifications can be used in appropriate combinations in order to obtain the effects of the combination. That is, it can be said that, by applying all the modifications, the electric conductor 6 is reliably moved when the low melting point metal 5 is melted, and the electric connection between the 1 st electrode 3 and the 3 rd electrode 11 can be reliably cut.

[ embodiment 3]

[ fuse element ]

Another embodiment of the fuse element 1 according to the present invention will be described. Note that the same reference numerals are given to the same components having the same functions as those described in embodiment 1, and the description thereof is omitted.

As shown in fig. 20 to 22, the fuse element 1 according to the present invention includes: an insulating substrate 2; a plurality of

electrodes

Fig. 20 and 22 are plan views of the conductor 6 seen through and from above the fuse element 1, and the conductor 6 is shown by a broken line. Fig. 21 is a sectional view taken along line C-C' of fig. 20.

The insulating substrate 2 has a substantially rectangular shape, and is formed in a square shape by an insulating member such as alumina, glass ceramic, mullite, or zirconia. The insulating substrate 2 may be a material for a printed wiring substrate such as a glass epoxy substrate or a phenol substrate.

A 1 st electrode 3 is formed on one end of the insulating substrate 2. Further, a 2 nd electrode 4 is formed on the other end portion of the insulating substrate 2, particularly, an end portion adjacent to the one end portion provided with the 1 st electrode 3. Further, a 3 rd electrode 11 is formed on an end portion of the insulating substrate 2 opposite to the end portion on which the 1 st electrode 3 is formed. The 1 st electrode 3 and the 3 rd electrode 11 are disposed to face each other on the surface 2a of the insulating substrate 2, and the 2 nd electrode 4 is provided so as to extend between the 1 st electrode 3 and the 3 rd electrode 11, in other words, the 2 nd electrode 4 is disposed so as to be separated from the 1 st electrode 3 and the 3 rd electrode 11.

The conductor 6 is made of a conductor material having a higher melting point and a lower resistance than the low melting point metal 5, and is disposed so as to overlap the 1 st electrode 3, the 2 nd electrode 4, and the 3 rd electrode 11 as shown in fig. 20 to 21, and is a substantially rectangular and plate-shaped member. The conductor 6 is not limited to a rectangular or plate shape, but this shape is adopted in the present embodiment from the viewpoint of ease of processing.

Specifically, the conductor 6 is preferably a high-melting-point and low-resistance metal material, and Ag, Au, Al, Cu alloy, or the like can be used. The conductor 6 is preferably made of Cu or a Cu alloy which is inexpensive, does not undergo natural oxidation, and is easily connected to the conductor by a low melting point metal. The conductor 6 forms a current path between the 1 st electrode 3 and the 3 rd electrode 11, and is not fused by self-heating (joule heat) by a current exceeding a rated value. However, the electric conductor 6 does not obviously prevent the fusing by self-heating.

[ operation of fuse element ]

In the fuse element 1, the conductor 6 is rotated and moved on the surface 2a of the insulating substrate 2 by melting of the low melting point metal 5 until the conductor is separated from the 1 st electrode 3 and the 3 rd electrode 11 among the 1 st electrode 3, the 2 nd electrode 4 and the 3 rd electrode 11, and the current passing path between the 1 st electrode 3 and the 3 rd electrode 11 can be cut off.

The conductor 6 is connected to the 1 st electrode 3 and the 3 rd electrode 11 in combination and the 2 nd electrode 4 by the low melting point metal 5 at different connection areas. Therefore, the conductor 6 is rotationally moved on the surface 2a of the insulating substrate 2 so as to be drawn by the different tensions to the combination of the 1 st electrode 3 and the 3 rd electrode 11 and the larger connection area of the 2 nd electrode 4 due to the melting of the low melting point metal 5.

Specifically, as shown in fig. 20 to 22, in the fuse element 1, the connection area of the low-melting-point metal 5b on the 2 nd electrode 4 to the conductor 6 is made larger than the sum of the connection area of the low-melting-point metal 5a on the 1 st electrode 3 to the conductor 6 and the connection area of the low-melting-point metal 5c on the 3 rd electrode 11 to the conductor 6. Therefore, the conductor 6 is drawn toward the 2 nd electrode 4 side in the arrow direction while rotating due to the melting of the low melting point metal 5b, and is rotated and moved on the surface 2a of the insulating substrate 2, and is held on the 2 nd electrode 4 by the low melting point metal 5b as shown in fig. 22.

As shown in fig. 20 and 21, the conductor 6 is disposed with its center portion O rotating on the 2 nd electrode 4, and is connected and held to the 1 st electrode 3, the 2 nd electrode 4, and the 3 rd electrode 11 by the low

melting point metals

5a, 5b, and 5c in a state where the end portions thereof slightly overlap with the 1 st electrode 3 and the 3 rd electrode 11, respectively.

Specifically, as illustrated in fig. 20, the conductor 6 is point-symmetrical about the center O, and preferably has a center of gravity at the center O. This is to facilitate the rotation of the conductor 6 about the center O. The angle θ defined by a line segment connecting the center O to the corner of the conductor 6₁This is the minimum rotation angle required for the conductor 6, and as shown in fig. 22, the angle defines the width required for the conductor 6 to rotate with respect to the 2 nd electrode 4.

The conductor 6 has protrusions 6c and 6d protruding in the rotational direction on the 1 st electrode 3 side and the 3 rd electrode 11 side, respectively. That is, the conductor 6 can be said to have a substantially zigzag shape.

The conductor 6 is a protrusion 6c connected to the 1 st electrode 3 via the low-melting-point metal 5a and to the 2 nd electrode 4 via the low-melting-point metal 5 b. Therefore, the protrusion 6c protrudes in the rotational direction, and is drawn obliquely by the molten low-melting metal 5 b. The conductor 6 is a protrusion 6d connected to the 3 rd electrode 11 via the low-melting-point metal 5c and to the 2 nd electrode 4 via the low-melting-point metal 5 b. Therefore, the protrusion 6d protrudes in the rotational direction, and is drawn obliquely by the molten low-melting metal 5 b.

The conductor 6 is rotated about the center O as a rotation center by applying a force pulling in a rotation direction to the respective protrusions 6c and 6d point-symmetric to the outside of the center O to generate a rotation moment.

Next, the operation of the fuse element 1 will be described with reference to a circuit diagram. As shown in fig. 23 (a), the fuse element 1 has a conductor 6 connected to the 1 st electrode 3, the 2 nd electrode 4, and the 3 rd electrode 11, and allows conduction between the 1 st electrode 3, the 2 nd electrode 4, and the 3 rd electrode 11. As shown in fig. 23 (B), when the low melting point metal 5 melts due to heat from the heater 12, the fuse element 1 rotates and moves the conductor 6 toward the 2 nd electrode 4, separates the conductor 6 from the 1 st electrode 3 and the 3 rd electrode 11, and cuts off the conduction between the 1 st electrode 3 and the 3 rd electrode 11. It is clear that the conduction between the 1 st electrode 3 and the 2 nd electrode 4, and between the 3 rd electrode 11 and the 2 nd electrode 4 is cut off. This also eliminates the energization of the heater 12, and the heater 12 stops generating heat.

[ modification 12]

Next, modified example 12 will be described as another example of embodiment 3. The same portions as those of the fuse element 1 described above are denoted by the same reference numerals, and the description thereof is omitted, and the differences will be specifically described.

As shown in fig. 24, the fuse element 1 according to the modification 12 includes a support member 7 for supporting the conductor 6 between the 1 st and 3

rd electrodes

3 and 11 and the 2 nd electrode 4 on the surface 2a of the insulating substrate 2. Fig. 24 is a sectional view corresponding to line C-C' in fig. 20. The support member 7 is disposed between the 1 st and 3

rd electrodes

The support member 7 supports the conductor 6 so as to be capable of rotating and moving, and is fixed to the surface 2a of the insulating substrate 2. That is, the support member 7 and the conductor 6 are not fixed, and the support member 7 is formed with a shape or coating such that the conductor 6 slips. In addition, since the conductor 6 is rotationally moved, the support member 7 is preferably provided in an arc shape.

When the low melting point metal 5 melts, the conductor 6 is supported by the support member 7 and can smoothly rotate toward the 2 nd electrode 4 side in a horizontal direction. That is, in the middle of the rotational movement of the low melting point metal 5 toward the 2 nd electrode 4, the conductor 6 is in a state in which the low melting point metal 5b on the 2 nd electrode 4 is cantilevered, and therefore it is conceivable that the conductor 6 is tilted on the surface 2a of the insulating substrate 2 and cannot be rotated properly. Therefore, the support member 7 can be supported to be capable of rotating appropriately by maintaining the horizontal state of the conductor 6.

[ modification 13]

Next, modified example 13 will be described as another example of embodiment 3. The same portions as those of the fuse element 1 described above are denoted by the same reference numerals, and the description thereof is omitted, and the differences will be specifically described.

As shown in fig. 25, the fuse element 1 according to modification 13 includes a guide portion 10 for guiding the movement of the conductor 6 on the surface 2a of the insulating substrate 2. Fig. 25 is a plan view of the fuse element 1 viewed from above through the conductor 6, and the conductor 6 is shown by a broken line.

The guide member 10 is fixed to the surface 2a of the insulating substrate 2, and has a guide function in a moving direction for rotating and moving the conductor 6 in a predetermined direction. The guide member 10 is preferably formed by two opposing arc-shaped members extending from the 1 st electrode 3 and the 3 rd electrode 11 side to the 2 nd electrode 4 side, and an insulator such as a resin material is used so that short circuit between both electrodes does not occur.

The guide member 10 extends to the same height as the conductor 6 on the surface 2a of the insulating substrate 2, and the guide member 10 is provided at a position serving as a guide rail for defining a moving direction from a side surface in a range where the conductor 6 is rotationally moved from an initial position to the 2 nd electrode 4 side. That is, the guide member 10 and the conductor 6 are in contact with each other from the initial position of the conductor 6 on the side surface, and the conductor 6 is not separated from the rotating operation until the conductor 6 is rotated toward the 2 nd electrode 4 side in a state where the low melting point metal 5 is melted.

Therefore, the guide member 10 can reliably rotate and move the conductor 6 toward the 2 nd electrode 4 side.

[ modification 14]

Next, modified example 14 will be described as another example of embodiment 3. The same portions as those of the fuse element 1 described above are denoted by the same reference numerals, and the description thereof is omitted, and the differences will be specifically described.

As shown in fig. 26, the fuse element 1 according to modification 14 includes a cover member 8 for protecting the 1 st electrode 3, the 2 nd electrode 4, the 3 rd electrode 11, the low melting point metal 5, the conductor 6, and the like on the surface 2a of the insulating substrate 2. Fig. 26 is a sectional view corresponding to line C-C' in fig. 20.

The cover member 8 is provided with a movement regulation portion 8a for regulating the rotation movable region of the conductor 6, and has a braking function for preventing the conductor 6 from moving in a direction other than the predetermined rotation direction. The cover member 8 can be formed of an insulating member such as a thermoplastic, ceramic, or glass epoxy substrate.

In the cover member 8, a movement regulation portion 8a extends to the same height as the conductor 6 on the surface 2a of the insulating substrate 2, and the movement regulation portion 8a is provided at a position where a predetermined gap is maintained from the initial position of the conductor 6 to the 1 st electrode 3 and the 3 rd electrode 11 side. That is, the movement regulation portion 8a and the conductor 6 do not contact each other at the initial position of the conductor 6, but when the rotation axis of the conductor 6 is deviated from the center portion O by the collision or the like in the state where the low melting point metal 5 is melted, the movement regulation portion 8a and the conductor 6 contact each other, and the rotation direction of the conductor 6 is forcibly set to the center portion O as the rotation axis. That is, the movement regulation portion 8a may be referred to as a guide member for rotating the conductor 6.

Even in a state where the movement of the conductor 6 is regulated by the movement regulation unit 8a, if the connection area of the conductor 6 on the low melting point metal 5b side is large, the conductor 6 is pulled toward the 2 nd electrode 4 side due to the tension of the low melting point metal 5b at all times, and the conductor 6 is rotationally moved so as to be caught on the 2 nd electrode 4.

Therefore, the movement regulating unit 8a regulates movement of the conductor 6 in a direction other than the rotational direction, thereby preventing the conductor 6 from moving to the 1 st electrode 3 and the 3 rd electrode 11 side and reliably performing rotational movement so as to be attached to the 2 nd electrode 4.

[ modification 15]

Next, modified example 15 will be described as another example of embodiment 3. The same portions as those of the fuse element 1 described above are denoted by the same reference numerals, and the description thereof is omitted, and the differences will be specifically described.

As shown in fig. 27, the fuse element 1 according to modification 15 is configured such that the conductor 6 has a shape having two recesses 6e and 6 f. Fig. 27 is a plan view of the fuse element 1 viewed from above through the conductor 6, and shows the conductor 6 by a broken line.

The conductor 6 has a substantially zigzag shape in the other example, but has a structure in which two recesses 6e and 6f are formed so as to be cut at the corner on the side farthest from the center O on the 1 st electrode 3 side and at the corner on the side farthest from the center O on the 3 rd electrode 11 side. That is, the area of the conductor 6 on the 1 st electrode 3 and the 3 rd electrode 11 side is reduced by the amount of the notch, and the area on the 2 nd electrode 4 side is increased. Therefore, the connection area of the conductor 6, the 1 st electrode 3, the 2 nd electrode 4, the 3 rd electrode 11 and the low melting point metal 5 is larger on the 2 nd electrode 4 side than on the total of the 1 st electrode 3 and the 3 rd electrode 11 side, and the tensile force by the molten low melting point metal 5b is increased.

Therefore, the fuse element 1 can reliably rotate and move the conductor 6 having the recesses 6e and 6f toward the 2 nd electrode 4.

Modification 15 may be a shape in which a portion not contributing to current conduction is cut out in order to reduce the size of conductor 6 as compared with modification 10. The conductor 6 can be easily moved by downsizing the conductor 6.

[ modification 16]

Next, modified example 16 will be described as another example of embodiment 3. The same portions as those of the fuse element 1 described above are denoted by the same reference numerals, and the description thereof is omitted, and the differences will be specifically described.

As shown in fig. 28, fuse element 1 according to modification 16 is configured such that conductor 6 has a shape in which two recesses 6e and 6f are formed in an arc-shaped cutout shape, as compared with modification 15. Fig. 28 is a diagram illustrating only the conductor 6, but the other portions are the same as in modification 15.

The conductor 6 has a substantially zigzag shape in the other example, but has a structure in which the recess portions 6e and 6f are formed so as to be cut in an arc shape at the corner portion on the side farthest from the center portion O on the 1 st electrode 3 side and at the corner portion on the side farthest from the center portion O on the 3 rd electrode 11 side, respectively. That is, the area of the conductor 6 on the 1 st electrode 3 and the 3 rd electrode 11 side is reduced by the amount of the notch, and the area on the 2 nd electrode 4 side is increased. Therefore, the connection area formed by the conductor 6, the 1 st electrode 3, the 2 nd electrode 4, the 3 rd electrode 11 and the low melting point metal 5 is larger on the 2 nd electrode 4 side than the total of the 1 st electrode 3 and the 3 rd electrode 11 side, and the tensile force by the molten low melting point metal 5b is increased.

Further, since the recesses 6e and 6f are cut in an arc shape, the conductor 6 has no corners, and thus, there is no portion that is caught during the rotational movement, and smooth rotation is possible.

The conductor 6 has a structure in which portions corresponding to the recesses 6e and 6f are formed as raised portions 6g and 6h that are raised so as to be separated from the surface 2a of the insulating substrate 2. That is, since the end face of the conductor 6 in the rotation direction is raised, smooth operation is possible when the conductor is attached to the 2 nd electrode 4, and rotation movement is prevented from being incomplete by being caught at the end of the 2 nd electrode 4.

Therefore, the fuse element 1 can reliably rotate and move the conductor 6 having the concave portions 6e and 6f and the warp portions 6g and 6h so as to be attached to the 2 nd electrode 4.

The modifications of embodiment 3 described above can be used in any combination, and it is obvious that the modifications can be used in appropriate combinations in order to obtain the effects of the combination. That is, it can be said that, by applying all the modifications, the electrical connection between the 1 st electrode 3 and the 3 rd electrode 11 can be reliably cut by reliably rotating and moving the conductor 6 when the low melting point metal 5 is melted.

In embodiment 3, as shown in fig. 28, for example, a support shaft S for supporting the conductor 6 may be provided, and the conductor 6 may be supported by the support shaft so that the center O does not deviate, and the conductor 6 may be supported by a simple structure without providing a guide portion or the like. The support shaft S may protrude from the 2 nd electrode 4, or may protrude from the cover member 8 when the cover member 8 is used. In addition, it is preferable to provide a recess or a through hole in the conductor 6 for receiving the support shaft S.

In addition, although the conductor 6 is described as an example of a metal plate such as Cu in the above embodiments 1 to 3, it is obvious that a stacked fuse unit of a low melting point metal and a high melting point metal may be used.

In the fuse element to which the present invention is applied, it is obvious that a heat source for melting the low melting point metal 5 is appropriately required regardless of the presence or absence of the built-in heater, and it is also obvious that a method of providing a heater externally or using self-heating of the conductor 6 may be employed.

Description of the reference symbols

1 a fuse element; 2 an insulating substrate; 2a surface; 2b a back side; 3, 1 st electrode; 4 a 2 nd electrode; 5a low melting point metal; 5a low melting point metal on the 1 st electrode; 5b a low melting point metal on the 2 nd electrode; 5c a low melting point metal on the 3 rd electrode; 6 an electrical conductor; 6a, 6b convex portions; 6c, 6d protrusions; 6e, 6f recesses; 6g and 6h warping parts; 7 supporting the member; 8a cover member; 8a movement regulation unit; 9 moving the prescribed member; 10 a guide member; 11 a 3 rd electrode; 12 heaters.

Claims

1. A fuse element is provided with:

an insulating substrate;

a plurality of electrodes disposed on the insulating substrate; and

a conductor connected to each of the plurality of electrodes via a low-melting-point metal and having a melting point higher than that of the low-melting-point metal,

the conductor is drawn by the melting of the low melting point metal to one of the plurality of electrodes by different tensions so as to be separated from at least one of the plurality of electrodes so as to have a larger connection area with the low melting point metal, thereby cutting off the current path between any of the electrodes.

2. The fuse element of claim 1,

the plurality of electrodes are composed of a 1 st electrode and a 2 nd electrode,

in the conductor, a connection area of the 2 nd electrode formed of the low melting point metal is larger than a connection area of the 1 st electrode formed of the low melting point metal.

3. The fuse element of claim 1,

the plurality of electrodes are composed of a 1 st electrode, a 2 nd electrode and a 3 rd electrode,

in the conductor, a connection area of the 2 nd electrode formed of the low melting point metal is larger than a sum of a connection area of the 1 st electrode formed of the low melting point metal and a connection area of the 3 rd electrode formed of the low melting point metal.

4. The fuse element according to any one of claims 1 to 3,

further comprises a predetermined member for defining the moving direction of the conductor when the low melting point metal is melted.

5. The fuse element according to any one of claims 1 to 3,

further comprises a guide member for guiding the moving direction of the conductor when the low melting point metal is melted.

6. The fuse element according to any one of claims 1 to 3,

further comprises a heater which is provided on the upper surface of the body,

the heater melts the low melting point metal by heat generated by energization.

7. The fuse element according to any one of claims 1 to 3,

in the conductor, an end portion of the low melting point metal on a side moving when melted is tilted upward in a direction separating from the insulating substrate.

8. The fuse element of claim 3,

the conductor is rotationally moved when the low melting point metal is melted, and has a line-symmetric shape with a rotational center position as a center.

9. The fuse element of claim 3 or claim 8,

the conductor rotates and moves when the low-melting-point metal is melted, and the center of gravity is located at the rotation center.

10. The fuse element according to any one of claims 1 to 3,

the conductor is made of Cu or Cu alloy.

11. The fuse element according to any one of claims 1 to 3,

the low-melting-point metal is solder paste.