JP4665750B2 - Fuse mounting structure and electrical junction box - Google Patents

Description

  The present invention relates to a fuse mounting structure and an electrical junction box, and more particularly to a fuse mounting structure with improved heat dissipation of a large current fuse having a large amount of heat generation.

  In electric circuits used in automobiles, fuses of various capacities are used, and a high current fuse of 60 to 250 amperes is interposed in a large current circuit from a battery to an alternator or the like. Since this type of large-current fuse generates a large amount of heat, the insulation material in the area that contacts the large-current fuse and the adjacent area is heated, causing melting at the contact area and distortion due to the thermal effect at the adjacent area. May occur. Therefore, it is necessary to take measures for heat dissipation at the mounting portion of the large current fuse.

For example, as an electrical junction box that enhances heat dissipation of a medium current circuit protection fuse interposed in an electrical circuit from a battery to a fan, an ABS motor, or the like, in Japanese Patent Laid-Open No. 2004-64871 (Patent Document 1), FIG. The electrical junction box shown is provided.
In the electrical junction box of Patent Document 1, a groove 3d is formed as a heat radiating space between the fuse 2 and the housing 3, and a slit 3e is provided on the bottom plate and the inner wall to make it difficult for heat to stay. Even if an overcurrent flows through 2, the housing 3 is configured not to melt.

The configuration of Patent Document 1 is effective for a fuse of a type that is fitted and fixed in a recess formed in an electrical junction box, but is molded with an insulating resin portion 20a as shown in FIG. As shown in FIGS. 10 (B) and 10 (C), an input terminal portion 20b using a large current fuse 20 having an input terminal portion 20b with a pair of bolt holes 20d and an output terminal portion 20c sandwiching the fusing portion. And the output terminal portion 20c on the bus bar 40 and cannot be applied to a fuse that is bolted.
Specifically, on the side of the electrical junction box to which the fuse 20 is attached, a pair of square columnar nut holding frames 1 are projected from the insulating plate 30, and the nuts N are accommodated and held in the center holes of the nut holding frame 1, The input terminal portion 20b and the output terminal portion 20c of the fuse 20 are overlapped with the entire surface of the terminal portion 41 of the bus bar 40 on the upper surface of the nut holding frame 1, and a bolt B is screwed into the nut N from above and fixed.
In this way, the entire surface of the terminal portion 41 of the bus bar is placed on the upper surface of the nut holding frame 1 because the fuse and the terminal of the bus bar stably receive the tightening load when the bolt is tightened.

  However, in the above structure, the entire surface of the terminal portion 41 of the bus bar 40 is in contact with the upper surface of the nut holding frame 1 protruding from the insulating plate 30, and the corresponding contact portion is tightly fixed by fastening bolts and nuts. Because there is no, it becomes easy to collect heat. Therefore, the contact surface of the nut holding frame 1 is directly affected by the heat generated during energization, and the heat generated by the large current fuse of 60 to 250 amperes increases. There is a risk of melting.

JP 2004-64871 A

  This invention is made | formed in view of the said problem, and makes it a subject to suppress the heating of the contact part of the terminal part of this fuse, and a bus-bar in a bolt fixing fuse.

In order to solve the above-mentioned problem, the present invention provides a fuse having a flat plate-like conductive material in which a pair of bolt hole terminal portions are opposed to each other with a fusing portion interposed therebetween, and an insulating resin portion in which the fusing portion is embedded. While using
A pair of nut holding frames project from the insulating plate, and the lower part of the nut having a screw hole at the center of the quadrangular column is accommodated and held in the nut holding frame, and the upper part protrudes from the upper surface of the nut holding frame. The terminal portions with bolt holes projecting from the bus bars arranged on the insulating plate are placed on the end surfaces of the nuts, the terminal portions of the fuses are overlapped with the terminal portions with bolt holes, and the bolts are connected to the fuses. It is configured to screw and fix to the nut through the bolt hole of the terminal part and the terminal part of the bus bar,
It provides a fuse mounting structure, characterized in that is provided a gap for heat radiation between the terminal portions of the upper surface and the bus bar of the nut hold frame.

  As described above, the height of the nut holding frame protruding from the insulating plate is lower than the nut that is bolted and fixed by overlapping the terminal portion of the fuse and the terminal portion of the bus bar, and the terminal portion of the bus bar and the nut holding frame The heat release generated without energization is retained and the nut holding frame is melted down by providing a heat dissipation gap between the nut holding frame and the bus bar terminal. Can be prevented.

In the fuse mounting structure, it is preferable that the nut holding frame has a square frame shape and the height thereof is half or less of the nut.
Thus, heat dissipation can be improved more by making a nut holding frame into the height below half of a nut.

Furthermore, it is good also as a structure which provides the protrusion part which has the cross-section L-shaped part which fits each corner of the said nut from four corners of the said nut holding frame, and makes the height of these protrusion parts also lower than the height of a nut.
The strength of the nut holding frame can be increased and the nut can be securely held and held by providing the protruding portion having the L-shaped section that fits each corner of the nut from the four corners of the nut holding frame as described above. it can.
Moreover, since the height of the protruding portion is lower than the height of the nut, the terminal portion of the bus bar does not come into contact with the protruding portion, so that the protruding portion can be prevented from being melted.
It is preferable that each of the protrusions is provided with a protrusion from the outer side surface of the rectangular tube portion to provide the L-shaped section.

  Furthermore, in the present invention, the fuse mounting structure is provided, the insulating plate and the bus bar are accommodated in the lower case and the upper case, the fuse mounting portion is provided in the upper case, and the fuse mounting portion is the fuse mounting portion. An opening is provided on both sides of the mounting portion of the insulating resin portion to expose the terminal portion with the bolt hole of the bus bar mounted on the upper surface of the nut, and the bolt is overlapped with the terminal portion with the bolt hole through the opening. An electrical junction box characterized by being fastened is provided.

As described above, by providing the upper case with a fuse mounting part that exposes the terminal part with the bolt hole of the bus bar, the fuse can be attached and detached with the upper case attached, and maintenance is performed when the fuse is replaced by fusing the fuse. Can be improved.
Further, by providing the mounting portion of the insulating resin portion of the fuse in the fuse mounting portion, the fuse can be stably held when the terminal portion of the fuse is bolted and fixed. And by providing this mounting part, it can prevent that a foreign material inserts into an upper case at the time of fuse replacement | exchange operation | work.
The electrical junction box is mounted in an engine room of a vehicle, and a bus bar input terminal is supplied with a power source current (raw power source), and is most suitable when the allowable current amount of the fuse is 60 amperes to 250 amperes. It will be a thing.

  As described above, according to the fuse mounting structure of the present invention, the nut holding frame and the bus bar terminal are protruded from the nut holding frame by screwing and fixing the fuse terminal portion and the bus bar terminal portion. A space for heat dissipation can be provided between the two portions. Therefore, it is possible to effectively dissipate heat during heat generation and prevent the nut holding frame from being melted.

In addition, according to the electrical junction box of the present invention having the fuse mounting structure, by providing a fuse mounting portion in the upper case, it is possible to attach and detach the fuse with the upper case mounted, thereby improving maintainability. be able to.
In addition, by providing a mounting portion for the insulating resin portion of the fuse in the fuse mounting portion, it is possible to stably hold the insulating resin portion of the fuse in the mounting portion described above, and foreign matter is prevented from flowing into the upper case during fuse replacement work. Can be prevented.

Embodiments of the present invention will be described with reference to the drawings.
1 to 5 show a first embodiment of the present invention, in which a bus bar is attached to a nut N accommodated and held in a pair of nut holding frames 10 protruding from an insulating plate 30 made of an insulating resin in an electrical junction box. 40 terminal portions 41 are placed, and the terminal portions 20b and 20c of the fuse 20 are stacked thereon and fixed with bolts B.

The fuse 20 is formed of the fuse shown in FIG. 10A, and the input terminal portion 20b and the output terminal portion 20c each provided with a bolt hole 20d are on the same plane with a fusing portion molded by the insulating resin portion 20a interposed therebetween. It is a shape that protrudes in a shape.
The fuse 20 of the present embodiment is provided in a circuit through which a power source current (raw current) is conducted, and is a large current fuse having an allowable current amount of 60 amperes to 250 amperes.

  As shown in FIGS. 2A and 2B, the pair of nut holding frames 10 projecting from the insulating plate 30 is a rectangular frame portion 10a at the height of h1 from the insulating plate 30, and four of the rectangular frame portions 10a. Projecting portions 10b having a L-shaped cross section that fit the respective corners of the nut N project from the upper surface of the corners. The height of these protruding portions 10b from the insulating plate 30 is h2. A space 10c for heat dissipation in which the nut N is exposed is formed between the adjacent protrusions 10b. The height h1 of the square frame is not more than half of the height h3 of the nut N.

  The nut N has a quadrangular prism shape as shown in FIG. 2B, and a screw hole Na is provided at the center. The lower part of the nut N is housed in a state embedded in the rectangular frame part 10a of the nut holding frame 10, and the upper part of the nut N protrudes from the upper surface of the rectangular frame part 10a, and the four corners of the protruding nut N Is surrounded by the protruding portion 10b, and the portion facing the space 10c between the protruding portions 10b is exposed to the outside. And the upper end surface of the nut N is made to protrude slightly from the upper part of the protrusion part 10b of four corners. In other words, the height h3 of the nut N protruding from the insulating plate 30 is higher than the height h1 of the square frame portion 10a and the height h2 of the protrusion 10b of the nut holding frame 10, and the nut N is accommodated. Thus, the upper portion of the nut N is protruded from the protruding portion 10 a of the nut holding frame 10.

  A pair of bus bars 40 (40A, 40B) connected to the input terminal portion 20b and output terminal portion 20c of the fuse 20 are fixed to the upper surface of the insulating plate 30, and terminal portions refracted in an L shape from these bus bars 40 are fixed. 41 is provided, and a bolt hole 41 a is provided at the center of the tip horizontal portion of the terminal portion 41.

  Each terminal portion 41 of the bus bar 40 is placed on the upper surface of the nut N protruding from the nut holding frame 10, and the bolt hole 41 a communicates with the screw hole Na of the nut N. At that time, the terminal portion 41 is in contact only with the upper surface of the nut N and is not in contact with the protruding portions 10 b at the four corners of the nut holding frame 10.

The insulating plate 30 to which the nut N and the bus bar 40 are attached is housed and fixed in the lower case 60 of the electric junction box 100 shown in FIGS. 3 and 5, and the upper case 50 is assembled to the lower case 60.
A substantially rectangular fuse mounting portion 51 is provided on the upper surface of the upper case 50. In the present embodiment, two fuse mounting portions 51 are provided side by side.

Each fuse mounting portion 51 is provided with a mounting portion 51a for stably holding the insulating resin portion 20a of the fuse 20 at the center, and openings 51b and 51c are provided on both sides thereof.
With the upper case 50 assembled to the lower case 60, the terminal portions 41 of the bus bars 40 placed on the nuts N are exposed inside the openings 51b and 51c.
In addition, on the outer surface side of the upper case 50, the input terminal portion 20 b and the output terminal portion of the fuse 20 are opened in the openings 51 b and 51 c with the insulating resin portion 20 a of the fuse 20 placed on the placement portion 51 a of the fuse mounting portion 51. 20c is set to be arranged.

  The fuse 20 is mounted by placing the fuse 20 on the fuse mounting portion 51 of the upper case 50. In this state, the input terminal portions 20b and 20c of the fuse 20 are overlapped on the upper surface of the terminal portion 41 of the bus bar on the upper surface of the pair of nuts N. In addition, the screw hole Na of the nut N, the bolt hole 41a of the terminal portion 41, the input terminal portion 20b of the fuse, and the bolt holes 20d of the output terminal portion 20c are in communication with each other.

  In this state, as shown in FIG. 4, the bolt B is connected from above the upper case 50 with the two washers W <b> 1 and W <b> 2, and the bolt hole 20 d of the fuse terminal portion and the bolt hole 41 a of the terminal portion 41. The fuse terminal portions 20b and 20c are fastened and fixed to the terminal portions 41 of the bus bar 40 as shown in FIG. In FIG. 4, the upper case 50 is omitted.

In the attached state of the fuse 20, as shown in FIG. A heat dissipation space S2 is provided between them.
Further, in the rectangular frame portion 10a where the protruding portion 10b of the nut holding frame 10 does not protrude, the space 10c between the protruding portions 10b is also a heat radiation space S1.
By providing the heat radiation spaces S1 and S2 in this way, even when the fuse 20 is a large current fuse and the amount of heat generated by energization is large, the generated heat is dissipated without stagnation and the heat to the nut holding frame 10 is obtained. By minimizing the influence, it is possible to prevent melting damage from occurring in the resin nut holding frame.
Further, by providing the protruding portion 10a protruding from the nut holding frame 10, the strength of the nut holding frame can be increased, and damage due to a tightening load at the time of bolt tightening can be prevented.
And since the terminal part 41 of the bus-bar 40 is exposed to the fuse attachment part 51 of the upper case 50 from opening 51b, 51c, it can aim at heat radiation from this exposed part.

  Further, the fuse 20 can be attached and detached while the upper case 50 is attached, and the maintainability can be improved. Furthermore, by providing the mounting portion 51a, the insulating resin portion 20a of the fuse 20 can be stably supported, and foreign matter can be prevented from entering the upper case during fuse replacement work or the like.

6A to 6C show a second embodiment of the present invention.
In the second embodiment, each of the nut holding frames 11 protruding in a pair from the insulating plate 30 protrudes from the insulating plate 30 with four protruding portions 11a having a L-shaped section that fits four corners of the nut N. I am letting. That is, the square frame portion having the closed cross section provided in the first embodiment is not provided.
The height of each projecting portion 11a is made lower than the height of the nut N, and the upper portion of the nut N protrudes from each projecting portion 11a, and the heat dissipation in which the nut N is exposed between each projecting portion 11a. A space 11b is formed. The nut N is fixed to the insulating plate 30 by being molded or press-fitted with the four projections 11 a surrounded by the four corners.

With this configuration, a space for heat dissipation is provided between the upper surface of each protruding portion 11a and the terminal portion 41 of the bus bar 40, and the tip of the nut N is formed in the space 11b where the nut N is exposed. A space for heat dissipation is provided up to the back surface of the terminal portion 41 of the bus bar 40 in contact with the surface.
Thus, since the part of the space 11b where the nut N is exposed is larger than that in the first embodiment, the heat dissipation can be further improved.
Since other configurations are the same as those of the first embodiment, description thereof is omitted.

7A to 7C show a first modification according to the second embodiment of the present invention.
The difference from the second embodiment is that projecting portions 12 a having a L-shaped section projecting from the insulating plate 30 are provided at two corners on the diagonal of the nut N.
By setting it as such a structure, the space 12b from which the nut N is exposed is formed between the protrusion parts 12a, and can improve heat dissipation.
In this embodiment, the abutment surface of each projecting portion 12a with which the nut N is fitted with the nut N is larger than the projecting portion 11a of the second embodiment in order to securely receive and hold the nut N. is doing.
Since other configurations are the same as those of the second embodiment, description thereof is omitted.

8A to 8C show a third embodiment of the present invention.
In the third embodiment, the pair of nut holding frames 13 protruding from the insulating plate 30 is formed only by the square frame portion of the first embodiment, and the height thereof is set to be half or less of the nut N. The nut N is press-fitted and fixed in the square frame portion 10a, or the nut N is molded and molded when the insulating plate 30 is molded, and the nut N is securely fixed to the nut holding frame 10.
By adopting the above-described configuration, the exposed portion of the nut N becomes larger as compared with the other embodiments, so that heat dissipation can be further improved.
Since other configurations are the same as those of the first embodiment, description thereof is omitted.

It is a figure which shows the fuse attachment structure of 1st Embodiment of this invention. The fuse attachment structure of the said 1st Embodiment is shown, (A) is a perspective view of a nut holding frame, (B) is a perspective view of the nut holding frame in which the nut was accommodated. The electrical junction box which mounts the fuse of 1st Embodiment is shown, (A) is a principal part expanded sectional view, (B) is a principal part enlarged plan view. It is a perspective view which shows the attachment operation | work of a fuse. It is sectional drawing which shows the attachment state of a fuse. The fuse attachment structure of 2nd Embodiment of this invention is shown, (A) is a perspective view of a nut holding frame, (B) is a perspective view of the nut holding frame in which the nut was accommodated, (C) was attached with the fuse. It is a perspective view which shows a state. The fuse mounting structure of the 1st modification which concerns on 2nd Embodiment of this invention is shown, (A) is a perspective view of a nut holding frame, (B) is a perspective view of the nut holding frame in which the nut was accommodated, (C). FIG. 3 is a perspective view showing a state where a fuse is attached. The fuse attachment structure of 3rd Embodiment of this invention is shown, (A) is a perspective view of a nut holding frame, (B) is a perspective view of the nut holding frame in which the nut was accommodated, (C) was attached with the fuse. It is a perspective view which shows a state. It is drawing which shows a prior art example. (A), (B), and (C) are drawings showing other conventional examples.

Explanation of symbols

10 Nut holding frame (first embodiment)
10a Square frame portion 10b Protruding portion 10c Space 11 between each protruding portion Nut holding frame (second embodiment)
11a Projecting portion (second embodiment)
11b Space between projecting portions (second embodiment)
12 Nut holding frame (first modification of the second embodiment)
12a Projecting portion (first modification of the second embodiment)
12b Space between projecting portions (first modification of the second embodiment)
13 Nut holding frame (third embodiment)
20 fuse 20a insulating resin portion 20b input terminal portion 20c output terminal portion 30 insulating plate 40 bus bar 41 bus bar terminal portion 50 upper case 51 fuse mounting portion 51a mounting portion 51b, 51c opening 60 lower case 100 electric connection box B bolt N nut

Claims (4)

While using a flat plate-like conductive material projecting a pair of terminal portions with bolt holes facing each other across the fusing portion, and a fuse having an insulating resin portion that embeds the fusing portion,
A pair of nut holding frames project from the insulating plate, and the lower part of the nut having a screw hole at the center of the quadrangular column is accommodated and held in the nut holding frame, and the upper part protrudes from the upper surface of the nut holding frame. The terminal portions with bolt holes projecting from the bus bars arranged on the insulating plate are placed on the end surfaces of the nuts, the terminal portions of the fuses are overlapped with the terminal portions with bolt holes, and the bolts are connected to the fuses. It is configured to screw and fix to the nut through the bolt hole of the terminal part and the terminal part of the bus bar,
Fuse mounting structure, characterized in that is provided a gap for heat radiation between the terminal portions of the upper surface and the bus bar of the nut hold frame.   2. The fuse mounting structure according to claim 1, wherein the nut holding frame has a square frame shape, and the height thereof is not more than half of the height of the nut.   The protrusion part which has the cross-section L-shaped part which fits each corner of the said nut from four corners of the said nut holding frame is provided, The height of these protrusion parts is also made lower than the height of a nut. Fuse mounting structure. The fuse mounting structure according to any one of claims 1 to 3, wherein the insulating plate and the bus bar are accommodated in the lower case and the upper case, and a fuse mounting portion is provided in the upper case, fuse mounting portion is provided with an opening to expose the bolt hole with the terminal portion of the bus bar placed on the upper surface of the nut on opposite sides of the mounting portion of the insulation Sophora fat portion of the fuse, the terminal portion of the fuse through an opening An electrical connection box characterized by being bolted over a terminal portion with a bolt hole.

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