JP2015091195A - Ignition prevention structure of on-vehicle feeder circuit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a novel ignition prevention structure of an on-vehicle feeder circuit capable of preventing occurrence of vehicle fire after tsunami or flood in a time of disaster, e.g., east Japan earthquake, without relying upon the waterproof structure of an on-vehicle feeder circuit.SOLUTION: In an on-vehicle feeder circuit 10 for feeding power from the power supply side to the load side, a junction 38 where an aluminum material 40 and a copper material 42 are bonded is provided at a part closer to the power supply side than the load side.

Description

  The present invention relates to an ignition prevention structure for an in-vehicle power supply circuit that is mounted on a vehicle such as an automobile and constitutes an electrical system.

  Conventionally, as an in-vehicle power supply circuit that is mounted on a vehicle such as an automobile and supplies power from the power source side of a battery or the like to the load side, an electrical connection box, a wire harness connected to the load side, and a connection provided at the terminal thereof Various members are used such as a combination of terminals and a connector to which a connection terminal provided at a terminal of the wire harness is mounted. Through such an in-vehicle power supply circuit, power distribution from the battery to various loads is performed in a space efficient manner.

  By the way, if water intrudes into such an in-vehicle power supply circuit, a short circuit or the like may occur. Therefore, the in-vehicle power supply circuit has a certain degree of waterproofing in consideration of water splashes assumed when the vehicle is used. Has been made. For example, in Japanese Patent No. 4585980 (Patent Document 1), with respect to an electric junction box as an on-vehicle power supply circuit, the gap of the case is sealed with a sealing material or the like, or a drain slope is provided at an appropriate position in the case. A waterproof structure that promotes drainage of water that has entered the interior is disclosed. Japanese Laid-Open Patent Publication No. 2001-85101 (Patent Document 2) discloses a connector as a vehicle-mounted power supply circuit to which a waterproof structure in which a waterproof seal is disposed is applied.

  However, the conventional waterproof structure of the in-vehicle power supply circuit is assumed to be used when the vehicle is used. Of course, it cannot be demonstrated. Many cases have been reported in which an electrical junction box or connector disposed near a battery of a vehicle ignites after an unexpected flood and a vehicle fire occurs, which is regarded as a problem.

  It is urgent to devise any countermeasures to prevent the in-vehicle power supply circuit from igniting after such unexpected flooding, but the in-vehicle power supply circuit should be designed to be waterproof even inundation due to a tsunami or flood. This not only increases the size and cost of the in-vehicle power supply circuit, but also hinders the function of the in-vehicle power supply circuit during normal vehicle use, and is not a realistic measure. Therefore, there has been a demand for an effective measure that can prevent ignition of the in-vehicle power supply circuit after flooding.

Japanese Patent No. 4585980 JP 2001-85101 A

  The present invention has been made in the background of the above-mentioned circumstances, and its solution is a novel that can prevent the occurrence of a vehicle fire after flooding without depending on the waterproof structure of the in-vehicle power feeding circuit. An object of the present invention is to provide an ignition prevention structure for an in-vehicle power supply circuit.

As a result of inventor's earnest research on the cause of ignition after vehicle inundation, the power supply side bus bar made of copper connected to the power supply line and the ground line particularly in the in-vehicle power supply circuit such as an electric junction box arranged near the battery. It has been found that ignition occurs at a site where the connected copper ground bus bars are arranged adjacent to each other. That is, when the vehicle is immersed in water containing an electrolyte such as salt water, electrolysis occurs between the power-side bus bar and the ground-side bus bar having a relatively large potential difference, and the cuprous oxide, which is a copper oxide at the anode, is generated. (Cu ₂ O) is deposited. When water is drawn, the deposited cuprous oxide is deposited between the power supply side bus bar and the ground side bus bar, thereby forming a short circuit between the two due to the cuprous oxide deposit. Even after flooding, the battery continues to be energized, and when the temperature rises to some extent, the cuprous oxide lowers its resistance, causing a short circuit. It was newly found out that a fire occurs when the insulating plate burns due to the heat generated at that time. The present invention has been completed based on such a new viewpoint.

  According to a first aspect of the present invention, in the in-vehicle power feeding circuit that feeds power from the power source side to the load side, a joint portion in which an aluminum material and a copper material are joined to a portion closer to the power source side than the load side is provided. An ignition prevention structure for an in-vehicle power feeding circuit, which is provided, is provided.

  According to this aspect, since the joint portion in which the aluminum material and the copper material are joined to the portion closer to the power supply side than to the load side is intentionally provided, the joint portion between the aluminum material and the copper material is dissimilar when immersed. Intermetallic corrosion can be actively generated. As a result, aluminum is eluted at the joint portion to form an oxide film, and power supply from the power source side to the load side is interrupted relatively early after the flooding, thereby preventing ignition due to continued energization.

  Here, the in-vehicle power supply circuit is mounted with an electrical connection box, a combination of a wire harness connected to the load side and a connection terminal provided at the terminal, and a connection terminal provided at the terminal of the wire harness. Various circuit members such as a connector are included. By providing the joint portion at a position closer to the power supply side than the load side of such an in-vehicle power supply circuit, it is possible to cut off energization on the upstream side and realize reliable fire prevention.

  In addition, the junction part of an aluminum material and a copper material includes all formed by well-known joining structures, such as welding, a press, and a mechanical clinch. Further, a case where one of the male terminal and the female terminal is made of an aluminum material and the other is made of a copper material and joined is also included in the joint portion of the present invention.

  According to a second aspect of the present invention, in the one described in the first aspect, the in-vehicle power supply circuit is configured by an electrical connection box that houses a bus bar as a conductive member, and the bus bar is the aluminum material. The aluminum bus bar and the copper bus bar as the copper material are joined together.

  According to this aspect, in the bus bar housed in the electrical junction box, a part of the bus bar disposed at a position close to the power supply side is configured as an aluminum bus bar, and is joined to the downstream bus bar by a simple structure. The ignition prevention structure of the present invention can be easily applied to an existing electrical junction box.

  A third aspect of the present invention is the one described in the first aspect, wherein the in-vehicle power feeding circuit is connected to the load side and a connection provided to the terminal and connected to the power source side. It is comprised by the combination of a terminal, The said connection terminal is comprised including the said junction part of the said aluminum material and the said copper material.

  According to this aspect, the in-vehicle power feeding circuit is configured by a combination of a wire harness connected to the load side and a connection terminal provided on the terminal and connected to the power supply side, closer to the power supply side than the load side. By using the connection terminal disposed at the position, a joint between the aluminum material and the copper material can be easily provided. In addition, by providing the connection portion on the connection terminal connected to the power supply side, it is possible to more reliably prevent energization to the downstream side and prevent the occurrence of fire.

  According to the present invention, the aluminum material and the copper material are joined to the portion closer to the power supply side than the load side. Intermetallic corrosion can be actively generated. As a result, aluminum is eluted at the joint portion to form an oxide film, and power supply from the power source side to the load side is interrupted relatively early after the flooding, thereby preventing ignition due to continued energization.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an exploded perspective view showing an ignition prevention structure for an in-vehicle power supply circuit as a first embodiment of the present invention. The principal part enlarged view of the II-II cross section in FIG. The whole perspective view which shows the ignition prevention structure of the vehicle-mounted electric power feeding circuit as 2nd embodiment of this invention. The principal part enlarged view of the IV-IV cross section in FIG.

  Embodiments of the present invention will be described below with reference to the drawings.

  First, FIGS. 1 and 2 show a structure for preventing ignition of an in-vehicle power supply circuit when it is submerged by using the in-vehicle power supply circuit ignition prevention structure according to the first embodiment of the present invention. The electric connection box 10 that is an in-vehicle power feeding circuit that feeds power from the power source side to the load side includes a bus bar circuit body 12 that constitutes an internal circuit, an upper case 14, and a lower case 16. Then, the upper case 14 and the lower case 16 are overlapped and assembled from both the upper and lower sides of the bus bar circuit body 12 to provide the electrical connection box 10 in which the bus bar circuit body 12 is accommodated inside the case. . The bus bar circuit body 12 is fixed to the case by known fixing means such as a bolt (not shown). Further, in the following description, unless otherwise specified, “upper” means the upper side in FIG. 1 where the upper case 14 is located, and “lower” means the lower side in FIG. 1 where the lower case 16 is located.

  As shown in FIG. 1, the upper case 14 and the lower case 16 are made of synthetic resin and have a substantially rectangular shallow box shape that opens toward the other side. Then, the upper case 14 and the lower case 16 are engaged, for example, by engaging engaging claws (not shown) provided in the upper case 14 through an engaging frame (not shown) provided in a corresponding portion of the lower case 16. So, they can be assembled together. Further, the peripheral wall of the upper case 14 or the lower case 16 is provided with a bracket mounting portion (not shown) at an appropriate place spaced in the circumferential direction, and a bracket (not shown) provided on the vehicle body side is mounted so that the electrical connection box 10 is provided. It is mounted and fixed at the appropriate place of the vehicle such as in the engine room.

  In addition, a plurality of connector housing portions 20 a to 20 c having a peripheral wall protruding upward from the upper case 14 are provided on the upper surface 18 of the upper case 14. Through the terminal insertion holes 22 formed in the bottom walls of the plurality of connector accommodating portions 20a to 20c, the bus bar terminals 30 provided at the end portions of the bus bars 28a to 28d to be described later are projected upward from the upper case 14. Yes. The bus bar terminals 30 form a group composed of a plurality of appropriate combinations and are arranged in the respective connector housing portions 20a to 20c.

  And the external connector provided in the terminal of the electric wire which comprises the external electric circuit which is not shown in figure is inserted with respect to connector accommodating part 20a-c. By inserting the external connector, an electric wire constituting an external electric circuit is connected to the bus bar terminal 30 protruding in the connector housing portions 20a to 20c.

  On the other hand, the bus bar circuit body 12 is configured such that the bus bars 28a to 28d are overlapped and supported on the surface of the substantially thin plate-like insulating plate 26. That is, on the surface of the insulating plate 26, bus bar fitting grooves 34 having a shape corresponding to the bus bars 28a to 28d that are supported by being overlapped are formed, and the bus bars 28a to 28d are fitted into the bus bar fitting grooves 34. Has come to be supported. As a result, the bus bars 28a to 28d are placed on the surface 36 of the insulating plate 26 on the arrangement surface 36, which is the bottom surface of the bus bar fitting groove 34, and assembled in a positioned state.

  Each of the bus bars 28a to 28d is a plate formed by punching a conductive metal plate or the like, and includes a bus bar terminal 30 at an appropriate position of the edge portion. These bus bar terminals 30 are formed on the insulating plate 26 so as to be bent at a substantially right angle upward. A base end portion of each bus bar terminal 30 is supported by a bottom wall portion of a bus bar fitting groove 34 formed in the insulating plate 26. On the other hand, the insulating plate 26 is made of synthetic resin and has a substantially rectangular shape.

  In the present embodiment, the power input to the bus bar terminal 30a of the bus bar 28c is branched to the load side via the bus bar terminal 30b of the bus bar 28c.

  And in the electrical junction box 10, the joining part 38 by which the aluminum material and the copper material were joined with respect to the bus bar 28c accommodated in the site | part close | similar to the power supply side of a battery rather than the load side of various electrical components etc. is provided. Yes. Specifically, the bus bar 28c has a bus bar terminal 30a close to the power source side, an aluminum bus bar 40 made of an aluminum material such as aluminum or aluminum alloy, and a bus bar terminal 30b close to the load side. A copper bus bar 42 made of a copper material such as an alloy is included. As shown in FIG. 2, the joining portion 38 is configured by superimposing a copper bus bar 42 on the aluminum bus bar 40 and joining them together by welding. In addition, the joining part 38 of an aluminum material and a copper material can be formed by well-known joining structures, such as a press and a mechanical clinch, other than welding. The bus bar 40 may be made of copper, and the bus bar 42 may be made of aluminum.

  Thus, by providing the joint part 38 in which the aluminum material and the copper material are joined to the portion closer to the power supply side than the load side, the aluminum bus bar 40 made of the aluminum material and the copper material are made when immersed. Corrosion between dissimilar metals can be positively generated at the joint portion 38 of the copper bus bar 42. As a result, aluminum elutes at the joint 38 and an oxide film is formed. Therefore, the power supply from the power supply side to the load side is interrupted at a position near the power supply side relatively early after the flooding, and the occurrence of ignition due to the continued power supply can be prevented.

  Next, with reference to FIGS. 3 to 4, the ignition prevention structure of the in-vehicle power supply circuit according to the second embodiment of the present invention will be described in detail. About members and parts having the same structure as the above embodiment, In the figure, the same reference numerals as those in the above embodiment are attached, and detailed description thereof is omitted. In the present embodiment, the in-vehicle power supply circuit is configured by a combination of a wire harness 46 connected to the load side and a connection terminal 48 provided at the terminal and connected to the power source side, and the connection terminal 48 is made of an aluminum material. The embodiment different from the above-described embodiment is shown in that it is configured to include the copper joint portion 50.

  More specifically, the wire harness 46 includes a plurality of electric wires 52, and one side (right side in FIG. 3) is connected to the load side while the other side (left side in FIG. 3). ) Is connected to the power supply. On the other side connected to the power source side, a plurality of electric wires 52 are projected from the end portion of the wire harness 46 so as to be substantially fan-shaped. And the insulation coating of the electric wire 52 is stripped off at the terminal of the electric wires 52, and the core wire 54 is exposed. By caulking the core wire caulking portion 56 of the connection terminal 48 to the core wire 54, the electric wire A connection terminal 48 is fixed and connected to 52. The connection terminal 48 is integrally configured to include such a core caulking portion 56, a box-like connection portion 60 having an opening 58 at the front end, and a connecting portion 62 extending therebetween. For example, a bus bar terminal 64 on the power supply side connected to the power supply line can be inserted into the opening 58 of the connection portion 60 from the front, so that the connection terminal 48 is connected to the power supply side. It has become.

  Further, as shown in FIG. 3, the connecting portion 62 of the connection terminal 48 is provided with a joint portion 50 in which an aluminum material and a copper material are joined. The joining part 50 of an aluminum material and a copper material is formed by the well-known joining structure similar to the previous embodiment. Specifically, the connection portion 60 to which the bus bar terminal 64 of the power supply side bus bar is connected is made of aluminum made of aluminum material such as aluminum or aluminum alloy, while the core wire 54 of the electric wire 52 connected to the load side is connected. The core wire crimping portion 56 to be connected is made of copper made of a copper material such as copper or a copper alloy. And as shown in FIG. 4, the junction part 50 is formed by the upper end part of the core wire crimping part 56 being piled up with respect to the lower end part of the connection part 60, and welding with each other. In addition, the joining part 50 of an aluminum material and a copper material can be formed by well-known joining structures, such as a press and a mechanical clinch other than welding. Further, the connection part 60 may be made of copper, and the core wire crimping part 56 may be made of aluminum.

  Thus, by providing the joint part 50 in which the aluminum material and the copper material are joined to the portion closer to the power source side than the load side, the aluminum connection part 60 and the copper material made of the aluminum material when immersed in water. It is possible to positively generate the corrosion between different metals at the joint portion 50 of the copper core wire crimping portion 56 made of Therefore, as in the previous embodiment, power supply from the power supply side to the load side is interrupted at a position near the power supply side relatively early after flooding, and the occurrence of ignition due to continued power supply can be prevented. It is. In addition, the connection terminal disposed at a position closer to the power supply side than the load side can be easily performed simply by changing to the connection terminal 48 according to the present invention.

  As mentioned above, although embodiment of this invention was explained in full detail, this invention is not limited by the specific description. For example, in the present embodiment, the ignition prevention structure of the present invention is applied to the power supply circuit composed of the electrical junction box 10 or the combination of the wire harness 46 connected to the load side and the connection terminal 48 provided at the terminal. Although an example in which is applied is described in detail, any in-vehicle power supply circuit can be similarly applied to any power supply circuit such as a connector or a power supply unit.

  Further, in the present embodiment, the connection terminal 48 is configured to include the aluminum material and the copper material joining portion 50. For example, one of the female terminal and the male terminal connected to each other is composed of the aluminum material, and the other is used. The case of being composed of copper material and joining is also included in the joint portion of the present invention.

10: Electrical connection box (vehicle power supply circuit), 28a to d: bus bar, 38, 50: joint, 40: bus bar, 42: bus bar, 46: wire harness (vehicle power supply circuit), 48: connection terminal (vehicle mounted) Power supply circuit)

Claims (3)

  In a vehicle-mounted power supply circuit that supplies power from the power source side to the load side, the vehicle-mounted power supply circuit is provided with a joint portion in which an aluminum material and a copper material are joined to a portion closer to the power source side than the load side. Fire prevention structure of power supply circuit.   The in-vehicle power supply circuit is configured by an electrical connection box that houses a bus bar as a conductive member, and the bus bar is formed by joining the aluminum bus bar as the aluminum material and the copper bus bar as the copper material. The ignition prevention structure of the vehicle-mounted power feeding circuit according to claim 1, comprising:   The in-vehicle power supply circuit is configured by a combination of a wire harness connected to the load side and a connection terminal provided at the terminal thereof and connected to the power supply side, and the connection terminal is the aluminum material and the copper material The ignition prevention structure of the vehicle-mounted power feeding circuit according to claim 1, comprising the joint portion.

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