JP2010015715A - Fuse - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuse capable of eliminating or suppressing occurrence of crack, burst or the like in a casing and capable of preventing ignition due to carbonization of a synthetic resin casing, when the fuse is blown-out. <P>SOLUTION: A fuse 10 includes a fuse element 1 having terminal parts 3 at both ends of a blown-out portion 2 and a casing 5 surrounding the blown-out portion 2, and an arc-extinguishing material 6 for extinguishing an arc generated when an element is blown-out is filled inside the casing 5, wherein the casing 5 is formed of an air permeable material so as to be non-conductive body as a whole. <P>COPYRIGHT: (C)2010,JPO&INPIT

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 casing has high confidentiality, so that 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 according to claim 1 includes a fuse element having terminal portions on both sides of a fusing portion and a casing surrounding the fusing portion, and is generated inside the casing at the time of the element fusing. A fuse filled with an arc extinguishing agent for extinguishing an arc is formed, wherein the casing is made of a breathable material and is entirely non-conductive.

  According to a second aspect of the present invention, in the fuse of the first aspect, the air-permeable material is made of ceramics, sintered metal, or a mixture thereof.

  The invention according to claim 3 is the fuse according to claim 1 or 2, wherein the casing surrounds the periphery of the fusing part of the element, and / or the terminal part is exposed to the outside. It consists of a cap body that closes both ends.

  According to a fourth aspect of the present invention, in the fuse according to the first or second aspect, the casing is formed by solidifying the periphery of the fusing portion with powder or granules with both terminal portions of the element exposed to the outside. It is characterized by.

  According to the fuse of claim 1, the casing surrounding the fusing part is formed of a breathable material. Therefore, by filling the casing with an arc extinguishing agent, the gas temperature rises and the internal pressure before fusing The rise can be suppressed, and the above-described problems such as cracking and rupture of the casing can be solved 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.

  According to the fuse of claim 2, in addition to the effect of claim 1, the breathable material is formed of ceramics, sintered metal, heat resistant synthetic resin, or a mixture thereof. In addition to having the required strength as a fuse, such as mechanical strength, processing with these breathable materials can be facilitated.

  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 3, in addition to the effect of the fuse of claim 1 or 2, the casing exposes the cylindrical body surrounding the fusing part of the element and / or the terminal part to the outside. The cap body closes both end portions of the cylindrical body, and these members have air permeability. Therefore, an increase in internal pressure in the casing can be suppressed even for such a fuse.

  According to the fuse of claim 4, in addition to the effect of the fuse of claim 1 or 2, the periphery of the fusing part is solidified with powder or granules with the casing exposing both terminal portions of the element to the outside. Since it consists of a thing, the ring which integrates the divided | segmented casing and the cap body which obstruct | occludes the both ends of a cylinder are unnecessary. Further, as in the case of the fuse, an increase in the internal pressure of the casing can be suppressed.

  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 as shown in FIG. 2 of Japanese Patent Laid-Open No. 9-63448, for example, Of course, the 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 connected by a suitable fastening member such as a bolt, nut, or screw. 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 the figure, the casing 5 has a cylindrical shape with both ends sealed with wall surfaces. From the casing A and the casing B along the cylindrical axis direction for easy assembly. It 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.

  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 total volume of the material, 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 a part of the casing 5 is made of a breathable conductor such as the sintered metal described above. 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, and both the casings A and B are fitted. 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, a curve P is for an in-vehicle fuse including the fuse 10 of the present invention, and a curve Q is for the general industrial fuse shown in contrast to the 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, a large number of fillers 6 around the element 1 extinguish the arc, but the expanded and high-pressure fusing gas, as shown in FIG. Since the material is formed of a breathable material, the fusing gas is discharged out of the casing 5 through the ventilation channel in the casing 5 as indicated by the arrow in the figure.

  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.

  FIG. 4 is an overall perspective view having a partially broken portion according to the second embodiment of the fuse 20 of the present invention.

  In the description of the present embodiment, only the points different from the fuse 10 of the first embodiment will be described, and the other points are completely the same as those of the first embodiment, and the description thereof will be omitted.

  That is, the fuse 10 of the first embodiment is of a type in which the casing 5 is divided into two, but the fuse 20 of the present embodiment is a type in which the casing 21 is fitted with the cap body 23 from both sides of the cylindrical body 22. (In the figure, the right cap body 23 is not shown for the explanation of the internal structure.)

  The fuse 20 of this embodiment is configured as follows.

  The fuse element 1A has substantially the same configuration as the fuse element 1 of the first embodiment.

  The cylindrical body 22 has a cylindrical shape with openings at both ends, and on each outer peripheral surface in the vicinity of both ends, a tapered retaining protrusion 22a is formed to prevent the cap body 23 described later from coming off.

  The cap body 23 is attached to each end portion of the cylindrical body 22, the insertion hole 23 a of the terminal portion 24 is formed on the end surface thereof, and the cap body 23 is disposed on the outer peripheral surface thereof. A retaining hole 23b that engages with the retaining protrusion 22a when mounted on the retaining member 22 is formed.

  In the method of assembling the fuse 20 of the present embodiment, first, the right cap body 23 (not shown) is inserted into the right end portion of the cylindrical body 22 so that the terminal portion 24 of the element 1A is exposed from the insertion hole 23a.

  Next, the retaining hole 23b of the cap body 23 is fitted into the retaining protrusion 22a of the cylindrical body 22, and the element 1A, the cylindrical body 22 and the cap body 23 are bonded with an adhesive, fastened with screws or the like, or by an appropriate tolerance. They are integrated by connecting means such as fitting.

  Next, the whole is stood up so that the left side opening of the cylindrical body 22 faces upward, and a predetermined amount of arc-extinguishing agent 6 is filled from the opening. When the filling is completed, the left cap body 23 is mounted in the same manner as described above, and the retaining hole 22b of the cap body 23 is fitted into the retaining protrusion 22a of the cylindrical body 22, and similarly, the two members are integrated with an adhesive or the like. Turn into.

  In this case, also in the casing 21 of the present embodiment, the cylindrical body 22 and / or the cap body 23 are formed of the air-permeable material described above in the first embodiment, provided that the casing 21 is entirely non-conductive. In the figure, the cylindrical body 22 is formed of a breathable material, and the cap body 23 is formed of a nonconductive material such as ceramics to form a nonconductive body as a whole.

  The fuse 20 of this embodiment can also be effectively applied to such a type of fuse, and as shown by the arrows in the figure, the blown gas generated when the element 1A is blown is effectively transferred from the casing 21 to the outside of the casing. The air can be exhausted, and the same effect as in the first embodiment can be obtained.

  FIG. 5 is an overall perspective view having a partially broken portion according to the third embodiment of the fuse 30 of the present invention.

  In the description of the present embodiment, only differences from the fuse 10 of the first embodiment will be described.

  In the fuse 30 of the present embodiment, the periphery of the fusing part 32 is solidified in a rectangular parallelepiped shape as shown in the figure or other shape with the powder or particles around both the terminal portions 31 and 31 of the element 1B exposed to the outside. A thing is integrated as a casing 33.

  That is, the casing 33 is obtained by mixing a heat-resistant powder fluid that solidifies with heat treatment together with an adhesive so as to ensure the porosity as described in Example 1, for example, and then sintering and hardening them. It is.

  As described above, the casing 33 of the present embodiment is normally formed entirely of a gas permeable material, so that the gas permeable material used here is, for example, a non-conductive material such as a permeable ceramic. Material is preferred.

  The fuse 30 of the present embodiment can be applied to such a casing type fuse without any trouble, and as shown by the arrows in the figure, the blowing gas when the element 1B is blown can be effectively transferred from the casing 33 to the casing 33. It can be effectively exhausted outside.

  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. It is a whole perspective view which has a partially broken part of 2nd Example of the fuse which concerns on this invention. It is a whole perspective view which has a partially broken part of 3rd Example of the fuse which concerns on this invention.

Explanation of symbols

1, 1A, 1B Fuse element 2 Fusing part 3 Terminal part 4 Mounting hole
5, 21, 33 Casing 6 Arc extinguishing agent
7 Arc extinguishing agent filling hole 8 Vent hole 9 Fuse receiving part 10 Fuse (present invention)
20 Fuse (present invention)
22 Cylinder 22a Retaining protrusion
23 cap body 23a insertion hole 23b retaining hole 30 fuse (present invention)

Claims (4)

A fuse comprising a fuse element having terminal portions on both sides of a fusing part, and a casing surrounding the fusing part, wherein the casing is filled with an arc extinguishing agent that extinguishes an arc generated at the time of the element fusing. Because
The fuse is characterized in that the casing is made of a breathable material and is a non-conductive body as a whole.   2. 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 is composed of a cylinder body that surrounds the periphery of the fusing part of the element, and / or a cap body that closes both ends of the cylinder body with the terminal part exposed to the outside. 2. The fuse according to 2.   3. The fuse according to claim 1, wherein the casing is made of a material in which the periphery of the fusing part is hardened with powder or granules with both terminal portions of the element exposed to the outside.

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