JP5675859B2 - fuse - Google Patents

Description

The present invention relates to a fuse used in the automotive field. More specifically, for example, in a fuse of a type in which an arc extinguishing agent is filled inside a casing such as a high-voltage fuse, the occurrence of cracking or rupture of the casing at the time of fusing is eliminated or suppressed. On obtaining fuses.

There are various types of fuses used in the automotive field. For example, there is a high-voltage fuse that cuts off an overcurrent such as a short-circuit current without causing smoke or ignition outside.

As is well known, the structure of this high-voltage fuse incorporates a fuse element (hereinafter sometimes simply referred to as an element) that forms a melted portion with a narrow cross section into an insulating cylinder, and extinguishes the arc around the fuse element. It is filled with an agent and the insulating cylinder is sealed.

When the fuse element is blown, the arc extinguishing agent extinguishes the arc generated from the melted part of the element around the element, absorbs Joule heat generated from the fuse element in the process until fusing, and delays the fusing time It fulfills its function.

However, in this high-pressure fuse, a large amount of high-temperature and high-pressure fusing gas is generated from the fusing portion when the element is blown, so that the pressure inside the casing rises. When the pressure of this gas rises, the confidentiality of the casing is high, so this gas cannot be held inside the casing,
As a result, there is a problem that the casing is cracked, ruptured or the like.

Further, in this case, since the fusing gas is high temperature and high pressure, its volume expansion is large and the arc extinguishing agent also expands. However, since the space in the casing is occupied by the arc extinguishing agent, the internal pressure is relieved. It is not possible to promote the occurrence of the cracks and ruptures.

Further, when the casing material is made of resin, the inner wall surface of the casing is carbonized by Joule heat or arc heat generated from the element at the time of melting, and leakage current continues to flow on the surface, resulting in a problem of ignition.

As a conventional technique for dealing with such a casing problem, techniques described in Patent Document 1 and Patent Document 2 can be seen.

However, although these technologies all touch the necessity of preventing damage to the casing and cooling it, the main purpose of each is to prevent the short circuit of the metal terminal part by covering the metal terminal part with a ceramic sheet. In other words, it is intended to reliably cut off the current under high voltage by the same means, and none of them focused on the casing material and did not lead to a fundamental solution.
JP-A-11-185596 (Claim 1, paragraph 0032, FIG. 1) JP 11-191355 A (Claim 1, paragraph 0004, FIG. 1)

The present invention has been made to solve such problems of the prior art, and eliminates or suppresses the occurrence of cracks, ruptures, etc. in the casing when the fuse is blown, and prevents ignition due to carbonization of the fuse casing. An object is to provide a fuse that can be prevented.

In order to solve the above-mentioned problem, the invention described in claim 1 includes a fuse element having terminal portions on both sides of a fusing portion, and a casing surrounding the fusing portion, and the casing has an inside at the time of fusing the fuse element. An arc extinguishing agent that extinguishes the generated arc is filled, and the inside of the casing is a fuse element and a fuse composed only of the arc extinguishing agent that is filled, and the casing is made of a breathable material, And a two-walled type consisting of one casing and the other casing along the axial direction of the casing. It is configured.

  According to a second aspect of the present invention, in the fuse of the first aspect, a convex portion is formed on a joint surface of the one casing, and a convex shape of the one casing is formed on a joint surface of the other casing. A concave groove that can be fitted into the part is formed.

According to a third aspect of the invention, the fuse according to claim 1 or 2, wherein the breathable material, characterized in that it is made of ceramic or sintered metal or a mixture thereof.

Invention of claim 4, exposed in the fuse according to claim 1, wherein the casing, said cylindrical body surrounding the periphery of the fusion portion of the fuse element, the pin portion to the outside characterized in that in a state consisting of a cap body for closing the opposite ends of the cylindrical body.

According to the fuse of claim 1, since the casing surrounding the fusing part is formed of a breathable material, filling the arc extinguishing agent inside the casing increases the temperature of the gas,
An increase in internal pressure before fusing can be suppressed, and problems such as cracking and rupture of the casing described above can be eliminated or suppressed.

In addition, since the fuse is a non-conductive body as a whole, and when the fuse is normally used, the atmosphere in the casing is always in a state of ventilation or breathing with the outside air through the casing. There is an effect.
Moreover, since the casing is configured in a split type composed of one casing and the other casing along the axial direction of the casing, assembly is facilitated.

  According to the fuse of claim 2, in addition to the effect of the fuse of claim 1, a convex portion is formed on the joint surface of one casing, and the one surface of the other casing has Since the concave groove that can be fitted into the convex portion of the casing is formed, the concave groove of the other casing is pushed into and fitted into the convex portion of one casing, so that it can be easily integrated.

  According to the fuse of claim 3, in addition to the effect of the fuse of claim 1 or 2, the air-permeable material is formed of ceramics, sintered metal, heat-resistant synthetic resin, or a mixture thereof. Therefore, it has the required strength as a fuse, such as heat resistance and mechanical strength, and can be easily processed with these breathable materials.

  Moreover, by using ceramics or a sintered metal material as the breathable material, the ignition problem due to carbonization of the casing can be effectively solved.

According to the fuse of claim 4, wherein, in addition to the effects of the fuse according to any one of claims 1 to 3, casing, said cylindrical body surrounding the periphery of the fusion portion of the fuse element, the pin portion the consists of a cap body for closing the opposite ends of the cylindrical body in a state exposed to the outside, because these members have a breathable, it can suppress an increase in internal pressure in the casing against such fuses.

  The best mode of the fuse according to the present invention will be described below with reference to the drawings.

FIG. 1A is an overall perspective view having a partially broken portion according to the first embodiment of the fuse 10 of the present invention, and FIG. 1B is an enlarged view of a portion P of the casing A in FIG. 2 is an overall perspective view of the fuse element 1 used in the fuse 10 of FIG.

1A, a fuse 10 of the present invention is filled in a fuse element 1 having terminal portions 3 and 3 on both sides of a fusing portion 2, a casing 5 surrounding the fusing portion 2, and the entire inside of the casing 5. And arc extinguishing agent 6.

As shown in FIG. 2 which is a detailed view of the fuse element 1 in FIG. 1A, the center fusing part 2 is formed with a narrow width, and both end parts are formed with a slightly wider width than the fusing part 2. Further, for example, an integral type in which two terminal portions 3 are formed by bending a metal mainly containing copper and containing a small amount of tin, lead, zinc or the like as an additive component or a thin plate in which the metal is laminated as a solder layer. belongs to. Further, the fusing part 2 has a notch 2a and a plurality of small holes 2b in a direction perpendicular to the longitudinal direction of the element 1 so that the fusing part 2 is fused within a predetermined time when a predetermined overcurrent flows through the part. The terminal portion 3 is provided with a mounting hole 4 for connecting to a counterpart device.

In this way, the fuse element 1 shown in the figure is an integral type in which the terminal portion 3 is integrated with the fusing portion 2, but for example, as described in FIG. 2 of JP-A-9-63448,
Of course, the terminal part 3 may be composed of a separate member with respect to the fusing part 2, and both members may be of a separated type in which they are coupled with appropriate fastening members such as bolts, nuts, screws, and the like. Which type of element 1 is used as the element 1 used in the fuse 10 of the present invention can be appropriately selected depending on its use, rated current, and the like.

Returning to FIG. 1A again, the arc extinguishing agent 6 extinguishes an arc generated when the element 1 is melted, and is a known one such as silica sand or alumina.

As shown in FIG. 1 , the casing 5 is of a cylindrical type whose both ends are sealed with wall surfaces (without reference numerals) , and the casing 5 and the casing A are arranged along the cylindrical axis direction for easy assembly. The casing B is divided into two types. A filling hole 7 for the arc extinguishing agent 6 is formed at one end of the outer peripheral surface of the casing B. In addition, as shown in FIG. 1, although the semi-cylindrical part of both casings A and B and its both wall surface part have shown the thing of the aspect which integrally molded both parts, about both wall surfaces, it is in the said aspect. It may replace with a cap body of another member instead.

Moreover, the casing 5 is formed of a breathable material and the casing 5 is formed as a non-conductive body as a whole, as shown in an enlarged view of the P part in FIG.

Here, the “breathable material” refers to a porous material that can release a high-temperature, high-pressure fusing gas generated when the element 1 is blown out of the casing 5. In this way, a flow path communicating with the outside of the casing 5 is formed. Specific examples of such materials include ceramics (including glass and earthenware), sintered metals, heat-resistant synthetic resins, and the like.

Note that a commercially available material can be used as such a breathable material. For example, alumina ceramics in which porous alumina is molded into a porous shape having a porosity of 45 to 52%, which is an average pore diameter of 5 to 40 mμ, and a ratio of the pore volume to the entire material volume, is commercially available. (Model: AZP-50, AZP-70, manufacturer: manufactured by Aszac Corporation). In addition to the above-mentioned ventilation characteristics, this material also has the material characteristics required for the casing 5 of the fuse 10 of the present invention, such as low thermal conductivity and predetermined bending strength.

In this way, by appropriately selecting a commercially available casing material or changing its manufacturing conditions as appropriate, it is possible to easily ensure the target ventilation characteristics of the fuse 10 of the present invention.

In addition, although the arrangement | positioning density of the axial direction of the casing 5 of the said vent hole, ie, a vent hole may be concentrated and arrange | positioned in the fusing part 2 vicinity on the casing 5, for example, the pressure in a case is applied to the element 1. When a current is passed, the pressure in the casing gradually increases as the temperature of the arc-extinguishing agent 6 increases until the fuse is blown, so that a substantially uniform pressure distribution is obtained in both the casing axial direction and the inner wall radial direction.

Therefore, the distribution of the air holes 8 in the casing 5 may be uniform in the casing axial direction.

Next, “the casing 5 as a whole is a non-conductor” in the present invention means that the above-described air-permeable conductor such as sintered metal may be used in a part of the casing 5. However, when the casing 5 is assembled and integrated, in order to prevent a short circuit from occurring between both ends of the casing, the casing as a whole has no electrical conductivity and has a predetermined withstand voltage.

Further, when the element 1 is melted, the melted gas generated from the melted portion 2 is instantaneously expanded with respect to the substantially sealed casing 5 to fill the casing 5, so that the atmosphere in the casing 5 is increased in pressure. Therefore, the material of the casing 5 preferably has a predetermined mechanical strength that resists external forces such as tension and bending acting on the material.

In addition, the use of the fuse 10 of the present invention is not particularly limited. For example, in an in-vehicle application such as an automobile, the installation location of the fuse 10 of the present invention may be in an environment close to the outside air. It is preferable to have the following characteristics.

The thickness of the casing 5 is not particularly limited, and an appropriate thickness can be adopted depending on the strength of the case material.

Further, in the present embodiment, the casing 5 has a circular cross section, but it is of course possible to have other shapes.

In order to assemble the constituent members of the fuse 10 of the present invention described above, first, the element 1 is placed on both ends of the casing A so as to be supported at both ends, and then the both ends of the element 1 are supported. The positioning groove 4a is fitted into both ends of the casing A. This completes the setting of the fuse element 1 to the casing A.

Next, after aligning both ends of the casing B with the positioning grooves 4a at both ends of the element 1, the concave groove 5b of the casing B is pushed into the convex portion 5a of the casing A and fitted into both the casings A and B. After the integration, a predetermined amount of arc-extinguishing agent 6 is injected from the arc-extinguishing agent filling hole 7 of the casing.

Next, a snap ring (not shown) is attached to the two groove portions 5c formed on the outer peripheral surfaces of the integrated casings A and B, and the inner peripheral side of the snap ring is pressurized to be deformed into the groove portion 5c of the casing. And the casing A and the casing B are firmly coupled to complete the assembly.

  Next, the operation and effect of the fuse 10 of the present invention thus obtained will be described.

In FIG. 1 (a), when energized from the terminal part 3 of the element 1 and the fusing part 2 reaches the melting point temperature of the fuse element material, an arc is generated from the fusing part 2 and a large amount of high-temperature fusing gas is produced. The melted part 2 of the element 1 is melted.

The graph of FIG. 3 shows the relationship between the fusing current at this time and the time required for fusing, with the former as the horizontal axis and the latter as the vertical axis, for in-vehicle fuses and industrial general fuses.

In the figure, the curve P is for an in-vehicle fuse including the fuse 10 of the present invention,
Curve Q is for the general industrial fuse shown in contrast to curve P. A curve R is a smoke generation characteristic curve of the resin-coated electric wire.

As shown in the figure, although the fuses of the curves P and Q are not required to have a characteristic located above the curve R due to their required characteristics, the curve P of the in-vehicle fuse of the present invention is It is a gently sloping curve, and it melts when overcurrent continues to flow to any position on this curve.

Returning to FIG. 1 (a) again, the large number of fillers 6 around the element 1 extinguish the arc.
As shown in FIG. 1 (b), the melted gas that has been expanded and pressurized has a material of the casing 5 made of a breathable material. Then, it is discharged out of the casing 5.

Therefore, according to the fuse 10 of the present embodiment, the high-temperature and high-pressure fusing gas generated at the time of fusing of the element 1 can be effectively released to the outside of the casing 5, and problems such as cracking and rupture of the casing 5 can be solved. Can be suppressed.

Further, the fuse 10 of the present invention is a non-conductive body as a whole, and further, due to the presence of a vent hole in the casing 5, the atmosphere in the casing 5 is always air and breathing through the casing 5 during normal use. Is under possible conditions. Therefore, a moderate cooling effect acts on the casing 5 at all times, and the ignition problem due to carbonization of the casing 5 whose material is made of resin can be solved.

Although the fuse 10 of the present embodiment described above has been described with respect to the cylindrical fuse 10 in which the casing 5 of the fuse 10 is divided into two, it goes without saying that other appropriate divided types may be used.

The present invention has been described based on the embodiments. However, the present invention is naturally not limited to the above embodiments, and various improvements and modifications can be made without departing from the spirit of the present invention. Needless to say. For example, the present invention has been described mainly for in-vehicle use. However, the present invention can also be preferably applied to arc-extinguishing-type fuses such as industrial high-voltage fuses, and these uses are also within the scope of the present invention. Is included.

FIG. 1A is an overall perspective view having a partially broken portion, and FIG. 1B is a view of a P portion in FIG. 1A. It is a partial enlarged view. FIG. 2 is an overall perspective view of a fuse element used in the fuse of FIG. 1. It is a figure which shows the fusing current-time relationship of the fuse of FIG.

1 Fuse element 2 Fusing part 3 Terminal part 4 Mounting hole
5 Casing 6 Arc extinguishing agent
7 Arc-extinguishing agent filling hole 8 Vent hole 9 Fuse receiving portion 10 Fuse (present invention)

Claims (4)

A fuse element having a terminal portion on both sides of the fusing part, and a casing surrounding the fusing part, the inside of the casing is filled with an arc extinguishing agent that extinguishes an arc generated at the time of fusing the fuse element, The fuse has a fuse element and only the arc extinguishing agent filled in the casing ,
The casing is formed of a breathable material;
Consists of a cylindrical body and both wall surfaces closing both ends of the cylindrical body, and as a whole is a non-conductive body,
A fuse characterized in that it is configured in a split type comprising one casing and the other casing along the axial direction of the casing.   A convex portion is formed on the joint surface of the one casing, and a concave groove that can be fitted into the convex portion of the one casing is formed on the joint surface of the other casing. The fuse according to claim 1.   3. The fuse according to claim 1, wherein the air-permeable material is made of ceramics or sintered metal, heat-resistant synthetic resin, or a mixture thereof. The casing includes the cylindrical body that surrounds the periphery of the fused portion of the fuse element, and a cap body that closes both ends of the cylindrical body with the terminal portion exposed to the outside. Item 4. The fuse according to any one of Items 1 to 3.

Images