JP2013235676A - Fuse - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fuse the housing of which can be prevented from being eroded, even if the fuse body has a high temperature.SOLUTION: A fuse 100 includes a fuse body 110 connected with a tab terminal 7 and interrupting a current equal to or higher than a rated current, and a housing 120 for housing the fuse body 110, and is attached to the attachment part 5 of an electric connection box 1. The housing 120 includes a body case 130 which houses the fuse body 110 while covering, and an outer case 140 provided between the body case 130 and the attachment part 5. An air layer 150 is provided between the body case 130 and the outer case 140.

Description

  The present invention relates to a fuse, and more particularly to a fuse mounted on a vehicle.

  Conventionally, various electronic devices are mounted on vehicles such as automobiles, and many power transmission lines for supplying desired electric power to these electronic devices have been routed. The power transmission line is provided with an electrical connection box (so-called fuse box) provided so that a plurality of fuses can be extracted in order to protect the electrical circuit of each electronic device.

  A fuse used in such an electrical junction box includes a conductive fuse body and an insulating housing that houses the fuse body. The fuse body has a pair of terminal portions connected to the counterpart terminal, a connecting portion that connects the pair of terminal portions, and a fusible portion that is provided in the connecting portion and blows off a current exceeding the rating (so-called overcurrent). These are integrally formed of metal. The pair of terminal portions includes a spring piece that is connected to a mating terminal provided in the electrical connection box, and a locking piece that is located on the outer side and is locked to the inner surface of the housing. The fusible part includes a fusing point (so-called heat spot) where the connecting part 112 becomes narrow and a low melting point metal attached to the connecting part 112.

  In such a fuse, a pair of terminal portions are connected to a counterpart terminal in the mounting portion by mounting the housing on the mounting portion of the electrical junction box. When a current exceeding the rating is supplied to the fusible portion of the fuse, the low melting point metal melts, the melted low melting point metal diffuses into the fusing point, and the melting point of the fusing point is lowered. Thereby, heat_generation | fever of a fusing location is accelerated | stimulated and a fusing location cuts out and can interrupt | block electricity_supply.

JP 2004-281078 A

  However, in the conventional fuse described above, for example, in the case of a high rating (100 amperes, 120 amperes, 140 amperes, etc.), the connecting portion and the fusible portion (particularly, the fused portion) are likely to generate heat, and the fuse body itself becomes high temperature. It is assumed that In this case, high-temperature heat generated in the fuse main body is transmitted from each locking piece to the inner surface of the housing, and the housing may be melted.

  Accordingly, an object of the present invention is to provide a fuse capable of preventing the housing from being melted even when the fuse body is at a high temperature.

  In order to solve the above-described problems, the present invention has the following features. First, the first feature of the present invention is that a fuse body (fuse body 110) that is connected to a counterpart terminal (tab terminal 7) and cuts off a current exceeding the rated value, and a housing (housing 120) that houses the fuse body. A fuse mounted on a mounting portion (mounting portion 5) of an electrical junction box (electric junction box 1), wherein the housing covers the fuse body and houses the fuse body (Main body case 130) and an outer case (outer case 140) provided between the main body case and the mounting portion, and an air layer (air layer 150) is provided between the main body case and the outer case. ) Is provided.

  According to this feature, an air layer is provided between the main body case and the outer case. Thus, for example, even in the case of high ratings (100 amps, 120 amps, 140 amps, etc.), the high temperature heat generated in the fusible part is transmitted to the main body case, and the heat of the main body case passes through the air layer. Released to the outside. For this reason, it becomes difficult for the temperature of the main body case itself to rise, and the main body case can be prevented from being melted. Even if the main body case is melted, the outer case is provided on the outer side of the main body case, so that the melting of the mounting portion of the electrical junction box can be reliably prevented.

  A second feature of the present invention is the fuse according to the first feature of the present invention, wherein the outer case is provided at a position including the outside of a contact portion between the fuse body and the body case. The gist.

  According to such a feature, the outer case is provided at a position including the outside of the contact portion between the fuse main body and the main body case. Thereby, even if the heat generated in the fuse body is transferred from the contact portion to the main body case, the heat of the main body case can immediately pass through the air layer and be released to the outside. For this reason, it is possible to more reliably prevent the temperature of the main body case itself from rising.

  A third feature of the present invention is the fuse according to the first or second feature of the present invention, wherein an upper end (upper end 141) of the outer case is in a state where the housing is mounted on the mounting portion. The gist is that the mounting portion is provided at a position higher than the upper end (the upper end 5A).

  According to this feature, the upper end of the outer case is provided at a position higher than the upper end of the mounting portion. Thereby, the heat of the main body case transmitted from the fuse main body passes through the air layer and is released to the outside without touching the mounting portion of the electrical junction box. For this reason, it becomes difficult for heat to be more reliably transmitted to the mounting part of the electrical junction box, and the melting of the mounting part of the electrical junction box can be reliably prevented.

  According to the characteristics of the present invention, it is possible to provide a fuse capable of preventing the housing from being melted even when the fuse body is at a high temperature.

FIG. 1 is an exploded perspective view showing an electrical junction box and a fuse according to the present embodiment. FIG. 2 is a cross-sectional view showing an assembled state of the electrical junction box and the fuse according to the present embodiment. FIG. 3 is an exploded perspective view showing the fuse according to the present embodiment. FIG. 4 is a front, side, and plan view showing the fuse body according to the present embodiment. FIG. 5 is a front, side, and plan view showing the housing body according to the present embodiment.

  Next, an embodiment of a fuse according to the present invention will be described with reference to the drawings. In the following description of the drawings, the same or similar parts are denoted by the same or similar reference numerals. However, it should be noted that the drawings are schematic and ratios of dimensions and the like are different from actual ones. Accordingly, specific dimensions and the like should be determined in consideration of the following description. Moreover, the part from which the relationship and ratio of a mutual dimension differ also in between drawings may be contained.

(Configuration of electrical junction box)
First, the configuration of the electrical junction box 1 to which the fuse 100 according to the present invention is mounted will be described with reference to the drawings. FIG. 1 is an exploded perspective view showing an electrical junction box 1 and a fuse 100 according to the present embodiment. FIG. 2 is a cross-sectional view showing an assembled state of the electrical junction box 1 and the fuse 100 according to the present embodiment.

  As shown in FIGS. 1 and 2, the electrical junction box 1 includes a box-like (partly in the drawing) box body 3 and a wiring board (not shown) housed in the box body 3. The box body 3 is provided with a mounting portion 5 that is open at the top and to which the fuse 100 is mounted, and a connector fitting portion (not shown) into which a connector of a wire harness routed in a vehicle such as an automobile is fitted. It has been.

  The mounting portion 5 is formed in a box shape having an upper opening, and a plurality of mounting portions 5 are provided on the box body 3. Inside the mounting portion 5, a strip-like tab terminal 7 (mating terminal) provided on a bus bar of a wiring board (not shown) is provided.

  Such an electrical junction box 1 is routed between a power source such as a battery mounted on the vehicle and various electronic devices, that is, on a power transmission line for supplying desired power to various electronic devices. .

(Fuse configuration)
Next, the configuration of the fuse 100 described above will be described with reference to the drawings. FIG. 3 is an exploded perspective view showing the fuse 100 according to the present embodiment. FIG. 4 is a view showing the fuse body 110 according to the present embodiment. FIG. 5 is a view showing the housing 120 according to the present embodiment.

  As shown in FIGS. 1 to 3, the fuse 100 is a type of fuse that is inserted into the mounting portion 5 of the electrical junction box 1, and cuts off the power supply from the power source to the electronic device. As shown in FIGS. 2 and 3, the fuse 100 is connected to a tab terminal 7 provided in the mounting portion 5 of the electrical connection box 1 to cut off a current exceeding the rating (so-called overcurrent) 110. And a housing 120 that houses the fuse body 110.

  As shown in FIGS. 3 and 4, the fuse body 110 includes a pair of terminal portions 111, a connecting portion 112 that connects the pair of terminal portions 111, and a current exceeding a rating (so-called excessive current) provided in the connecting portion 112. And a fusible portion 113 that melts when an electric current is applied, and these are integrally formed of metal.

  The pair of terminal portions 111 includes a box-shaped terminal main body 111A arranged in parallel to each other, a spring piece 111B provided inside the terminal main body 111A, and an outer side of the terminal main body 111A and latched to the inner surface of the housing 120. And 111C of elastic locking pieces. The elastic locking piece 111C protrudes toward the inner surface of the housing 120, and stands upright in an inclined state from the bottom wall of the terminal body 111A.

  The connecting portion 112 is provided along the insertion direction of the tab terminal 7 to the pair of terminal portions 111, and is bent from the outer wall (bottom surface) of the terminal body 111A to connect the pair of terminal portions 111.

  The fusible portion 113 includes a heat spot 113A in which the connecting portion 112 becomes narrower, a low melting point metal 113B formed of a metal (for example, tin or tin alloy) having a melting point lower than that of the connecting portion 112, and a low melting point metal 113B. And caulking pieces 113C for caulking and fixing.

  As shown in FIGS. 3 and 5, the housing 120 includes a housing body 121 that houses the fuse body 110 from the upper opening 121 </ b> A, and a housing cover 122 that is attached to the housing body 121 from the opening 121 </ b> A side. Yes.

  The housing main body 121 is made of an insulating synthetic resin. The housing main body 121 includes a main body case 130 that covers the fuse main body 110 and accommodates the fuse main body 110, and an outer case 140 that is provided outside the main body case 130. An air layer 150 capable of releasing heat of the main body case 130 to the outside is provided between the main body case 130 and the outer case 140.

  The main body case 130 is formed in a rectangular tube shape whose lower side branches in two directions. A pair of terminal accommodating chambers 131 for accommodating the pair of terminal portions 111 are provided inside the main body case 130. Each terminal accommodating chamber 131 is formed with a locking receiving groove 132 for locking and receiving an elastic locking piece 111C provided outside the terminal main body 111A. Further, on the front and rear surfaces of the main body case 130, engagement protrusions 133 that are engaged with the housing cover 122 are formed.

  The outer case 140 is formed integrally with the main body case 130 so as to protrude laterally from both side surfaces of the main body case 130. The outer case 140 is provided between the main body case 130 and the mounting portion 5 of the electrical junction box 1. That is, the outer case 140 supports the main body case 130 in contact with the mounting portion 5 of the electrical junction box 1 in a state where the housing 120 is mounted on the mounting portion 5 of the electrical junction box 1.

  The outer case 140 is provided at a position including the outside of the contact portion between the fuse body 110 and the body case 130 (in this embodiment, the elastic locking piece 111C). The upper end 141 of the outer case 140 is provided at a position higher than the upper end 5A of the mounting portion 5 of the electrical connection box 1 in a state where the housing 120 is mounted on the mounting portion 5 of the electrical connection box 1 (see FIG. 2). The lower end 142 of the outer case 140 is provided at a position higher than the lower end 134 of the main body case 130.

  The housing cover 122 is made of a permeable material (for example, polyethersulfone (PES)) so that the fusible portion 113 of the fuse body 110 can be visually recognized. The housing cover 122 is formed with an engaging portion 122 </ b> A that engages with the engaging protrusion 133 of the housing main body 121.

(Fuse assembly method)
Next, a method for assembling the above-described fuse 100 will be briefly described.

  First, after a pair of terminal portions 111, a connecting portion 112, and a fusible portion 113 are punched or bent into a single sheet metal, a low melting point metal 113B is crimped and fixed to the connecting portion 112, and heat welding is performed. Let Then, the pair of fuse main bodies 110 are assembled in a box shape, and the end portions of the connecting portions 112 are bent so that the pair of fuse main bodies 110 face each other, thereby forming the fuse main body 110 shown in FIGS.

  Next, the fuse body 110 is mounted in the housing body 121. Then, as shown in FIG. 2, the elastic locking piece 111 </ b> C of the fuse body 110 is locked in the locking receiving groove 132 of the housing body 121.

  Next, the housing cover 122 is mounted from the opening 121 </ b> A side of the housing main body 121, and the engaging portion 122 </ b> A of the housing cover 122 is engaged with the engaging protrusion 133 of the housing main body 121. Thereby, the housing main body 121 and the housing cover 122 are fixed in a state where the fuse main body 110 is accommodated in the housing 120, and the fuse 100 is assembled.

  Thereafter, when the fuse 100 is mounted on the mounting portion 5 (see FIGS. 1 and 2) of the electrical junction box 1, the tab terminal 7 is inserted into the terminal body 111A. At this time, the spring piece 111B presses the tab terminal 7 inserted into the terminal body 111A toward the inner surface of the terminal body 111A. Thereby, the terminal part 111 and the tab terminal 7 are mutually connected.

  Here, since the air layer 150 is provided between the main body case 130 and the outer case 140, even if high-temperature heat generated in the fuse main body 110 is transmitted from the elastic locking pieces 111C to the inner surface of the main body case 130, the air layer 150 can be released.

  The fuse 100 mounted in the electrical junction box 1 connects the power source and the electronic device, and when a current exceeding the rating (so-called overcurrent) is applied to the fusible portion 113, the low melting point metal 113B. Melts. Then, the molten low melting point metal 113B diffuses to lower the melting point of the heat spot 113A. As a result, the heat generation of the heat spot 113A is promoted, the heat spot 113A is melted, and the power supply from the power source to the electronic device is interrupted.

(Action / Effect)
In the present embodiment described above, the air layer 150 is provided between the main body case 130 and the outer case 140. Thus, for example, even in the case of a high rating (100 amperes, 120 amperes, 140 amperes, etc.), the high temperature heat generated in the fusible portion 113 is transmitted to the main body case 130, and the heat of the main body case 130 is transferred to the air layer 150. Is released to the outside. For this reason, the temperature of main body case 130 itself becomes difficult to raise, and the main body case 130 can be prevented from being melted. Further, even if the main body case 130 is melted, the outer case 140 is provided outside the main body case 130, so that it is possible to reliably prevent the mounting portion 5 of the electrical connection box 1 from being melted. .

  In the present embodiment, the outer case 140 is provided at a position including the outside of the contact portion (elastic locking piece 111 </ b> C) between the fuse body 110 and the body case 130. Thereby, even if the heat generated in the fuse body 110 is transferred from the contact portion to the main body case 130, the heat of the main body case 130 can immediately pass through the air layer 150 and be released to the outside. For this reason, it is possible to more reliably prevent the temperature of the main body case 130 itself from rising.

  In the present embodiment, the upper end 141 of the outer case 140 is provided at a position higher than the upper end 5 </ b> A of the mounting portion 5 of the electrical junction box 1. Thereby, the heat of the main body case 130 transmitted from the fuse main body 110 passes through the air layer 150 and is released to the outside without touching the mounting portion 5 of the electrical junction box 1. For this reason, it becomes difficult for heat to be more reliably transmitted to the mounting part 5 of the electrical junction box 1, and the melting damage of the mounting part 5 of the electrical junction box 1 can be prevented reliably.

  In the present embodiment, the lower end 142 of the outer case 140 is provided at a position higher than the lower end 134 of the main body case 130. Thereby, the material of the outer case 140 can be reduced, and the manufacturing cost of the fuse 100 can be reduced.

(Other embodiments)
Although the contents of the present invention have been disclosed through the embodiments of the present invention as described above, it should not be understood that the descriptions and drawings constituting a part of this disclosure limit the present invention. From this disclosure, various alternative embodiments, examples, and operational techniques will be apparent to those skilled in the art.

  For example, the embodiment of the present invention can be modified as follows. Specifically, the outer case 140 has been described as being provided at a position including the outside of the contact portion (elastic locking piece 111C) between the fuse main body 110 and the main body case 130, but is not limited thereto. In addition to the elastic locking piece 111C, it may be a contact portion between the fuse main body 110 and the main body case 130, that is, it may be provided between the main body case 130 and the mounting portion 5 of the electrical junction box 1. .

  Further, the outer case 140 has been described as being formed integrally with the main body case 130, but is not limited thereto, and is formed separately from the main body case 130 and attached to the main body case 130. May be.

  Moreover, although the upper end 141 of the outer case 140 was demonstrated as what is provided in the position higher than the upper end 5A of the mounting part 5 of the electrical junction box 1, it is not limited to this, A position equivalent to the upper end 5A, It may be provided at a position lower than the upper end 5A.

  Similarly, the lower end 142 of the outer case 140 has been described as being provided at a position higher than the lower end 134 of the main body case 130, but is not limited thereto, and is provided at a position equivalent to the lower end 134. Also good.

  Moreover, although the housing main body 121 and the housing cover 122 were demonstrated as what is fixed by latching with the engaging protrusion 133 and the engaging part 122A, it is not limited to this, By other lock mechanisms etc. It may be fixed.

  As described above, the present invention naturally includes various embodiments that are not described herein. Therefore, the technical scope of the present invention is determined only by the invention specifying matters according to the scope of claims reasonable from the above description.

DESCRIPTION OF SYMBOLS 1 ... Electric junction box 3 ... Box main body 5 ... Mounting part 5A ... End surface 7 ... Tab terminal (mating side terminal)
DESCRIPTION OF SYMBOLS 100 ... Fuse 110 ... Fuse main body 111 ... Terminal part 111A ... Terminal main body 111B ... Spring piece 111C ... Elastic locking piece 112 ... Connection part 113 ... Soluble part 113A ... Heat spot 113B ... Low melting point metal 113C ... Clamping piece 120 ... Housing 121 ... Housing body 121A ... Opening 122 ... Housing cover 122A ... Engagement part 130 ... Body case 131 ... Terminal accommodation chamber 132 ... Locking accommodation groove 133 ... Engagement projection 134 ... Lower end 140 ... Outer case 141 ... Upper end 142 ... Lower end 150 ... Air layer

Claims (3)

A fuse body that is connected to a counterpart terminal and cuts off a current exceeding the rating, and a housing that houses the fuse body, is a fuse that is attached to a mounting portion of an electrical connection box,
The housing is
A body case that covers the fuse body and accommodates the fuse body;
An outer case provided between the main body case and the mounting portion;
A fuse, wherein an air layer is provided between the main body case and the outer case. The fuse of claim 1,
The fuse is characterized in that the outer case is provided at a position including the outside of the contact portion between the fuse body and the body case. A fuse according to claim 1 or claim 2, wherein
The fuse is characterized in that an upper end of the outer case is provided at a position higher than an upper end of the mounting portion in a state where the housing is mounted on the mounting portion.

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