JP2010218687A - Fuse - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuse of a novel structure for regulating a sticking position of a low melting-point metal with high precision at an element part where the surface of a wide part is extended and exposed around a stuck low melting-point metal, and for suppressing spread of the low melting-point metal on the surface of the wide part. <P>SOLUTION: An expansion resistance part 56, which suppresses expanding of a low melting-point metal 50 stuck to the surface of a wide part 32 by a width dimension larger than that of a fusing part 36, is formed around the sticking region of the low-melting point metal 50, at least on both sides in the width direction of the wide part 32 and on the side opposite to the fusing part 36. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a fuse for protecting electric wires and electrical equipment from overcurrent.

  2. Description of the Related Art Conventionally, fuses are used for the purpose of protecting electric wires and electric devices from overcurrent in electric circuits such as automobiles. In such a fuse, a low melting point metal such as tin is attached to the element part of a conductive plate made of a high melting point metal such as copper, and the fusing characteristics in the element part due to the formation of an alloy by diffusion of the low melting point metal. Improvements are being made. In other words, not only in dead shorts far exceeding the fuse rating, but also in currents that do not blow immediately or abnormal short-circuit currents, the melting time of the element part can be shortened by diffusion of low melting point metal. ing.

  In general, the element portion is formed with a wide portion which is widened to improve heat dissipation and the like on both sides of a fusing portion whose width is reduced and the cross-sectional area is reduced. And the low melting-point metal has adhered to the surface of this wide part (refer patent document 1).

  By the way, when the melted low melting point metal is attached to the wide part, in the case of the element part having a relatively small current capacity, the width dimension of the wide part is smaller than the amount of the low melting point metal to be attached. The entire width is covered with a low melting point metal. On the other hand, in the element portion having a relatively large current capacity, the width of the wide portion is larger than the amount of the low melting point metal attached. For this reason, the surface of the wide melting portion around the low melting point metal attached to the surface of the wide portion is covered with the low melting point metal not only on the fusing portion side and the opposite side but also on both sides in the width direction of the wide portion. It often spreads and is exposed.

  However, when the surface of the wide portion is widely exposed around the low melting point metal as described above, it is difficult to accurately define the adhesion position of the low melting point metal. In addition, it is difficult to make a visual judgment because there is no mark or the like when confirming and checking the adhesion position of the low melting point metal. Furthermore, if the low melting point metal spreads too much on the surface of the wide part, the diffusion property to the high melting point metal and the fusing property may become unstable. In addition, the low melting point metal adhesion position and adhesion area in the wide part varies between products, which will never give a good impression to the user, etc. There is also a risk of connection.

JP-A-9-265891

  The present invention has been made in the background as described above, and the problem to be solved is that the width dimension of the wide portion is made larger than the attached low melting point metal so that the circumference of the low melting point metal is increased. In the element part where the surface of the wide part spreads and is exposed, it is possible to define the adhesion position of the low melting point metal with high accuracy and to suppress the spread of the low melting point metal on the surface of the wide part. By this, it is possible to easily carry out visual confirmation and inspection of the low melting point metal adhering to the surface of the wide part, and it is also possible to stabilize the target fusing characteristics by the low melting point metal, The object is to provide a fuse having a novel structure in which the reliability and value of the product are improved.

  That is, the present invention has an element portion in which a wide portion is provided in at least one of energization directions of a narrow fusing portion, and a low melting point metal having a melting point lower than that of the element portion is attached to the surface of the wide portion of the element portion. In such a fuse, the low melting point metal is attached to the surface of the wide part with a width dimension larger than the width dimension of the fusing part, and at least the width direction of the wide part is around the adhesion area of the low melting point metal on the surface of the wide part. An extended resistance portion that suppresses the spread of the low melting point metal is formed on both sides and on the opposite side of the melted portion.

  In the fuse having the structure according to the present invention, when the low melting point metal spreads on the surface of the wide portion, the extended resistance portion must be overcome. At that time, the expansion resistance part acts like a levee or a weir against the spread of the low melting point metal, or the frictional resistance is increased due to the increase in the contact area. Energy is greatly required for exceeding the extended resistance portion. Thereby, the low melting point metal is prevented from spreading beyond the extended resistance portion on the surface of the wide portion, and a region surrounded by the extended resistance portion is set as a predetermined specific position, and the region Therefore, it is possible to stably attach the low melting point metal.

  As a result, the adhesion region of the low melting point metal on the surface of the wide portion can be accurately defined. In addition, when manufacturing a large number of fuses, the same extended resistance portion is formed in each fuse, and the adhesion region of the low-melting point metal is defined at the same position. It becomes possible to carry out easily, accurately and quickly. In addition, the low melting point metal can be accurately attached to the surface of the wide part at a predetermined position, so that the target fusing characteristics can be stabilized, and the dispersion of the low melting point metal between the products can be suppressed. Reliability and product value are also improved.

  In addition, the extended resistance part can be employed in various shapes that are formed so as to protrude from the surface of the wide part and increase the resistance against spreading of the low melting point metal attached to the surface of the wide part. For example, in addition to one or a plurality of protrusions extending in contact with or along the outer peripheral edge of the low melting point metal attached to the surface of the wide portion, a lattice-like protrusion, or a plurality of independent protrusions A convex part etc. can be employ | adopted and you may employ | adopt combining them arbitrarily.

  In addition, the low melting point metal attached to the surface of the wide part has a melting point lower than that of the element part, and can realize fusing promotion by alloying (diffusion) with the metal that forms the wide part with melting. Any known one can be used. For example, in addition to tin, aluminum, lead, silver, magnesium, etc., alloys thereof can be selected according to required characteristics in consideration of the material of the wide portion.

  In addition, the low melting point metal should just be adhered so that it may not detach | leave with respect to the predetermined adhesion area | region in the surface of a wide part. Specifically, for example, the low melting point metal is adhered to the wide part in the molten state and directly fixed, or the solid low melting point metal is fixed to the wide part with an appropriate wax material or adhesive, or by caulking or the like. It is also possible to melt and fix it after mechanically fixing to the wide part.

  Further, in the present invention, a mode in which the periphery of the adhesion region of the low melting point metal on the surface of the wide portion is roughened, and an extended resistance portion is formed by the rough surface is suitably employed.

  In such an aspect, the extended resistance portion composed of a large number of convex portions formed on the surface of the wide portion by roughening is effective in spreading from the initial adhesion region to each direction with respect to the low melting point metal. Can be prevented. In addition, since the extended resistance function with respect to the low melting point metal is exhibited in the entire roughened area, for example, compared to the case where one protrusion is formed at a specific position, the low melting point metal attached It is possible to stably obtain the intended extended resistance function even with respect to some amount (attachment area) or deviation of the attachment position.

  In addition, the processing method for obtaining the “rough surface” which is one of the configurations of the present embodiment is not particularly limited as long as the extended resistance portion protruding from the surface of the wide portion can be formed. Well-known processing methods such as blasting and etching can be employed.

  Moreover, the formation area of a rough surface should just be present in the width direction of a wide part at the circumference | surroundings of the adhesion | attachment area | region of a low melting-point metal, and the opposite side of a fusing part, and may comprise an extended resistance part. For example, the entire surface of the wide portion excluding the low melting point metal adhesion region may be roughened.

  Further, in the present invention, at least one edge of the concave groove is built-up by forming a concave groove extending along the periphery of the adhesion region around the adhesion region of the low melting point metal on the surface of the wide portion. A mode in which the extended resistance portion is formed by protruding may be adopted.

  In such an embodiment, it is possible to form a ridge extending in a direction orthogonal to the spreading direction of the low melting point metal attached to the wide portion, which is lower than when, for example, scattered projections are provided. A more effective expansion resistance function can be exerted on the outer peripheral portion of the melting point metal.

  In addition, a ridge is formed on at least one side in the groove width direction of the formed single groove. That is, by forming one concave groove, there is one concave groove and at least one convex line outside the low melting point metal adhesion region. Therefore, not only the expansion resistance function by the ridges but also the expansion resistance function based on the storage action in the concave groove is exhibited, and a large resistance force can be exhibited against the expansion of the low melting point metal. In this aspect, a plurality of concave grooves may be formed in parallel.

The disassembled perspective view which shows the fuse as 1st embodiment of this invention. The principal part enlarged plan view of the fuse shown by FIG. The principal part enlarged view in the III-III cross section of FIG. The principal part enlarged plan view of the fuse as 2nd embodiment of this invention. The principal part enlarged view in the VV cross section of FIG.

  Hereinafter, in order to clarify the present invention more specifically, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 shows a fuse 10 as a first embodiment of the present invention. The fuse 10 has a structure in which a fuse body 12 that is a current-carrying member is covered with a housing 13 for electrical insulation.

  The fuse body 12 includes a first terminal portion 14 for an alternator, a second terminal portion 16 for a battery, and four output terminal portions 18 and 20. A first bus bar portion 22 is connected to the first terminal portion 14. Further, a second bus bar portion 24 is connected to the second terminal portion 16.

  A large current element portion 26 is provided so as to connect the first bus bar portion 22 and the second bus bar portion 24. In addition, element portions 28, 28, 30, and 30 are provided between the first bus bar portion 22 and the second bus bar portion 24 and the output terminal portions 18, 18, 20, and 20, respectively, so as to connect each other. ing.

  Each of these element portions 26, 28, 28, 30, 30 includes a fusing portion located in the middle portion in the energizing direction and wide portions located on both sides thereof. The wide portion has a width dimension larger than that of the melted portion and has a larger current cross-sectional area, and is designed to be disconnected at the melted portion when energized exceeding the allowable power.

  Specifically, the large current element portion 26 includes a first wide portion 32 and a second wide portion 34 extending from both opposing edges of the first bus bar portion 22 and the second bus bar portion 24, and the first wide portion. 32 and the second widened portion 34 and a fusing portion 36 that connects the opposite ends of the distal end.

  Similarly, the element portion 28 includes a first wide portion 38, a second wide portion 40, and a fusing portion 42, and extends across the opposing edge portions of the first bus bar portion 22 and the output terminal portion 18. ing. The element portion 30 includes a first wide portion 44, a second wide portion 46, and a fusing portion 48. The element portion 30 extends between the second bus bar portion 24 and the opposite edge portion of the output terminal portion 20. Yes.

  As described above, the fuse body 12 including the first and second terminal portions 14 and 16 and the output terminal portions 18 and 20, the bus bar portions 22 and 24, and the element portions 26, 28, and 30 is electrically conductive. It is integrally molded with the material. Specifically, for example, the fuse body 12 of the present embodiment can be obtained by subjecting a thin metal plate made of a copper alloy or the like to press working such as punching or bending.

  The fuse body 12 of the present embodiment obtained in this way has a substantially constant thickness dimension except for the element part 30 and the whole excluding the first terminal part 14 and the second terminal part 16. It is formed to spread on one plane. The element part 30 is slightly thinner than other parts. Further, the first terminal portion 14 and the second terminal portion 16 are bent at substantially right angles at the connecting portion between the first bus bar portion 22 and the second bus bar portion 24.

  Further, the low melting point metal 50 is attached to each of the element portions 26, 28 and 30. The adhesion position of the low melting point metal 50 is the tip of the first wide portion 32, 38, 44, which is one wide portion of each element portion 26, 28, 30, and the tip end portion on the connection side with the fusing portions 36, 42, 48. Has been.

  In the element portions 28 and 30, circular wide portions 52 and 54 are formed at the tips of the first wide portions 38 and 44. And the low melting-point metal 50 is adhered so that one surface of these wide parts 52 and 54 may be covered over the whole. That is, in the element portions 28 and 30 having a small width dimension, the widened portions 52 and 54 are formed in order to secure the adhesion area of the low melting point metal 50. On the other hand, since the first wide portion 32 is large in the large current element portion 26, the low melting point metal 50 is adhered so as to partially cover one surface of the first wide portion 32.

  The low melting point metal 50 can adjust the fusing at the fusing parts 36, 42, 48 of the element parts 26, 28, 30 and the like. For example, tin, phosphorus, solder, etc. Adopted according to the target function and characteristics. That is, by providing the low melting point metal 50 in close contact with the surface of the element portions 26, 28, and 30 of the fuse body 12 made of a high melting point metal, the low melting point metal 50 is heated and melted during abnormal energization such as intermittent short current. In addition, a reductive function for the fusible metal forming the element portions 26, 28, and 30 is exhibited, and a rapid fusing can be realized by promoting an increase in energization resistance and heat generation in the element portions 26, 28, and 30. Is possible. Alternatively, by allowing the low melting point metal 50 to absorb heat generated during energization of the element portions 26, 28, and 30 based on the large thermal conductivity and endothermic action of the low melting point metal 50, a motor lock current or the like is allowed. Or imparting delayed fusing characteristics.

  In order to attach the low melting point metal 50 to the first wide portions 32, 38, 44, for example, the low melting point metal 50 can be melted and attached. Specifically, the low melting point metal 50 in the first wide portions 32, 38, 44 is brought into contact with the respective adhesion planned portions of the first wide portions 32, 38, 44 by heating and melting the low melting point metal 50. The low melting point metal 50 can be attached to each of the first wide portions 32, 38, and 44 by utilizing the wettability to the melt and the surface tension of the molten low melting point metal 50.

  By the way, in the first wide portion 32 of the high current element portion 26 to which the low melting point metal 50 is adhered to a part of the surface, an extended resistance portion 56 is provided around the adhesion region of the low melting point metal 50.

  In other words, in the present embodiment, the low melting point metal 50 is attached to the tip portion at the central portion in the width direction (vertical direction in FIG. 2) of the first wide portion 32. Accordingly, the fusing part 36 side of the outer peripheral edge (outer peripheral contour) of the low melting point metal 50 extends along the edge of the first wide part 32. Further, in the outer peripheral edge portion of the low melting point metal 50, both the width direction both sides of the first wide portion 32 and the opposite side of the fusing portion 36 are spaced inward from the outer peripheral edge portion in the first wide portion 32. It extends over the surface. The spreading width of the low melting point metal 50 is larger than the fusing part 36 and smaller than the first wide part 32.

  On the other hand, the surface 58 to which the low melting point metal 50 is adhered in the first wide portion 32 is roughened over the entire portion excluding the adhesion region of the low melting point metal 50. The rough surface processing in the present embodiment is performed, for example, by using a press die having a pressing surface on which a large number of protrusions are formed, pressing the press die against the surface 58 of the first wide portion 32, and the like. It is done.

  As shown in FIGS. 2 and 3, a large number of small concave portions 60 that open to the surface 58 are formed on the surface 58 subjected to such roughening. In the present embodiment, the concave portions 60 are formed in a dense state with a small distance from each other over the entire portion of the surface 58 of the first wide portion 32 excluding the adhesion region of the low melting point metal 50.

  Each recessed portion 60 is formed with an extended resistance portion 56 formed of an annular protrusion protruding from the surface 58 of the first wide portion 32 at the peripheral edge of the opening. In short, in this embodiment, the extended resistance portions 56 made of small annular protrusions have a small distance from each other over substantially the entire surface 58 of the first wide portion 32 except for the adhesion region of the low melting point metal 50. It is formed in a densely spaced state.

  As a result, the extended resistance portion 56 is provided around the low melting point metal 50 attached to the surface 58 of the first wide portion 32 over the entire circumference except for the edge portion on the fusing portion 36 side. is there.

  Further, as shown in FIG. 1, a housing 13 is assembled to the fuse body 12 having the above-described structure. The housing 13 has an upper and lower divided structure. The upper cover 62 and the lower cover 64 are overlapped and connected to each other so as to sandwich the fuse body 12 from both sides in the plate thickness direction. It is fixedly attached to.

  Each of these upper and lower covers 62 and 64 has a substantially flat plate shape, and the bus bar portions 22 and 24 of the fuse body 12, the element portions 26, 28 and 30, and the base end portions of the output terminal portions 18 and 20. Is covered from above and below.

  In short, in the fuse 10 of this embodiment configured by assembling the housing 13 with respect to the fuse body 12, each terminal portion 14, 16, 18, 20 is outward from the outer peripheral edge portion of the housing 13 at least at the tip portion. It has a protruding structure. Then, an external energization cable (not shown) is connected to each of these terminal portions 14, 16, 18, and 20.

  The upper and lower covers 62 and 64 are provided with a pin mechanism for positioning and fixing the fuse body 12, a window for visually confirming the state of each element part 26, 28 and 30, and the upper and lower covers 62 and 64. A locking mechanism or the like for connection is appropriately provided, but since these are well-known ones and are not the gist of the present invention, a detailed description is omitted.

  In the fuse 10 of the present embodiment as described above, since the extended resistance portion 56 is formed so as to surround the outer peripheral edge portion of the low melting point metal 50 attached to the first wide portion 32, the low melting point metal 50 is melted. In order to spread in a state, it is necessary to get over the extended resistance portion 56.

  Here, since the extended resistance portion 56 protrudes at a predetermined height from the surface 58 of the first wide portion 32 to which the low melting point metal 50 is attached, in order to get over the extended resistance portion 56, it is simply a flat surface. Compared with the case of extending 58, a large flow energy is required. Therefore, resistance is exerted against the expansion (spreading) of the low melting point metal 50 on the surface 58 of the first wide portion 32, and the expansion of the low melting point metal 50 is suppressed. Note that the expansion of the low melting point metal 50 to the fusing part 36 can be prevented based on the surface tension of the low melting point metal 50 and the like due to the small width dimension of the fusing part 36.

  As a result, it is possible to accurately and stably define the adhesion region of the low melting point metal 50 on the surface 58 of the first wide portion 32. Further, by improving the positional accuracy of the low melting point metal 50, it is possible to easily and accurately check the quality of the adhesion region of the low melting point metal 50 by visual inspection or the like when manufacturing a large number of fuses. Moreover, stabilization of the target fusing characteristic and improvement of commercial value are also achieved.

  The first embodiment of the present invention has been described in detail above. However, the present invention is not construed as being limited by the specific description in the first embodiment.

  For example, as in the second embodiment shown in FIG. 4, the extended resistance portion 66 made of a ridge extending along the periphery of the attached low melting point metal 50 is formed on the surface 58 of the first wide portion 32. It may be adopted.

  The extended resistance portion 66 can be formed by, for example, pressing the first wide portion 32 using a press die having a ridge on the press surface. That is, by such press work or the like, the first wide portion 32 is formed with a substantially V-shaped concave groove 68 that opens to the surface 58 and extends as shown in FIG. In addition, a ridge extending continuously over the entire length of the groove along the tip edge of the outer side wall is formed at the opening edge of the groove 68, and the extended resistance portion 66 is formed by this ridge. 66 are formed in a protruding manner.

  In particular, in this embodiment, on the surface 58 of the first wide portion 32, the expansion resistance is extended so as to extend in parallel to the protruding direction (energization direction) of the first wide portion 32 on both sides of the low melting point metal 50 in the width direction. Concave grooves 68 and 68 forming the portion 66 are formed. In addition, a recessed groove 68 that forms the extended resistance portion 66 is also formed behind the low melting point metal (on the side opposite to the fusing portion 36) so as to extend in the width direction of the first wide portion 32. The extended resistance portion 66 extending so as to surround the low melting point metal 50 is formed by the three linearly extending concave grooves 68.

  Each of the concave grooves 68 has an end portion located inward by a predetermined distance from the outer peripheral edge of the first wide portion 32, and any of the concave grooves 68 is an outer peripheral portion of the first wide portion 32. Not open to.

  Also in the fuse of the present embodiment including the first wide portion 32 as described above, the low melting point metal 50 is surrounded by the extended resistance portion 66 in the entire periphery except the fusing portion 36 side. Any of the same effects as the embodiment can be exhibited.

  In the second embodiment, the three concave grooves 68 are formed independently of each other. However, for example, both end portions of the concave groove 68 positioned behind the expansion resistance portion 66 are connected to the expansion resistance portion. One recess groove 68 that extends in a U-shape as a whole may be formed by continuing each one end portion of the pair of recess grooves 68 and 68 positioned on both sides of 66. Alternatively, it is also possible to form one concave groove 68 having an arc shape that curves and extends so as to surround the periphery of the expansion resistance portion 66.

  In the second embodiment, the groove 68 is formed in a single line around the adhesion region of the low melting point metal 50. However, a plurality of grooves may be formed in parallel, and the adhesion region of the low melting point metal 50 may be formed. Including, it may be formed over the entire surface of the first wide portion 32.

  Furthermore, the groove 68 extending in the protruding direction of the first wide portion 32 and the groove 68 extending in the width direction can be formed so as to intersect each other. Thereby, the extended resistance portion 66 extending in a lattice shape can be formed around the low melting point metal 50 on the surface 58 of the first wide portion 32.

  In the element portions 28 and 30 as well, the present invention is applied by adopting the same structure as the high current element portion 26 in the first and second embodiments for the adhesion region of the low melting point metal 50. It is also possible. The number of formed element parts is not limited, and it can be applied to a single element part or a fuse having various structures integrally including two, three, four, or six element parts. The present invention can be applied.

10: fuse, 26: element portion for large current (element portion), 32: first wide portion (wide portion), 34: second wide portion (wide portion), 36: fusing portion, 50: low melting point metal, 56 : Extended resistance portion, 58: surface, 66: extended resistance portion, 68: recessed groove

Claims (3)

A fuse having an element portion provided with a wide portion in at least one of energization directions of a narrow fusing portion, and a low melting point metal having a melting point lower than that of the element portion attached to the surface of the wide portion of the element portion ,
The low melting point metal is attached to the surface of the wide part with a width dimension larger than the width dimension of the fusing part, and at least the wide part around the adhesion area of the low melting point metal on the surface of the wide part. A fuse comprising an extended resistance portion that suppresses the spread of the low-melting-point metal on both sides in the width direction and on the opposite side of the fusing portion.   2. The fuse according to claim 1, wherein a periphery of the adhesion region of the low melting point metal on the surface of the wide portion is roughened, and the extended resistance portion is formed by the rough surface.   A concave groove extending along the periphery of the adhesion region is formed around the adhesion region of the low melting point metal on the surface of the wide portion, so that at least one edge of the concave groove protrudes in an overlaid manner. The fuse according to claim 1, wherein the extended resistance portion is formed.

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