JP2015091154A - Electric connection box - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electric connection box of a novel structure, capable of preventing the occurrence of a vehicle fire after flooded, without a waterproof structure of the electric connection box.SOLUTION: An electric connection box 10 includes a bus bar circuit body 12 having a plurality of bus bars 28a-d disposed on an insulating plate 26 and including a power side bus bar 28c connected to a power line and a ground side bus bar 28d connected to a ground line. The power side bus bar 28c and the ground side bus bar 28d are disposed mutually adjacently. One of the power side bus bar 28c and the ground side bus bar 28d is made of aluminum, whereas another is made of copper.

Description

  The present invention relates to an electrical junction box mounted on a vehicle such as an automobile, and more particularly to an electrical junction box having a fire prevention structure after being flooded.

  Conventionally, an electric junction box is provided at an appropriate place in an electrical system such as an automobile, and power distribution from a battery to various loads is performed efficiently. Specifically, a bus bar circuit body in which a power source side bus bar connected to a power source line such as a battery and a ground side bus bar connected to the ground line are arranged on an insulating plate is accommodated in the electrical junction box. Therefore, power distribution is performed.

  By the way, if water enters the inside of such an electrical junction box, there is a possibility that a short circuit of the bus bar circuit body may occur. Therefore, the electrical junction box has a certain degree of waterproofing in consideration of water splash expected when using the vehicle. Measures are being taken. For example, as described in Japanese Patent No. 4585980 (Patent Document 1), the gap between the cases of the electrical junction box is sealed with a sealing material or the like, or the water that has entered the interior by providing a drain slope at an appropriate place in the case It is known to encourage the drainage of water.

  However, since the conventional waterproof structure of the electrical junction box is assumed to be used when the vehicle is used, sufficient waterproof effect is exhibited in unexpected cases such as flooding due to tsunami or flood at the time of disaster such as the Great East Japan Earthquake. Of course it can't be done. Many cases have been reported in which an electrical junction box near the battery of a vehicle ignites and a vehicle fire occurs after unexpected flooding.

  It is urgent to devise any measures to prevent the electrical junction box from igniting after such unexpected flooding, but applying a waterproof structure to the electrical junction box that assumes flooding due to tsunami, flooding, etc. Not only does this increase the size and cost of the electrical junction box, but it may also hinder the function of the electrical junction box during normal vehicle use, which is not a realistic measure. Therefore, there has been a demand for an effective measure that can prevent ignition of the electrical junction box after flooding.

Japanese Patent No. 4585980

  The present invention has been made in the background of the above-mentioned circumstances, and its solution is a novel structure capable of preventing the occurrence of a vehicle fire after flooding without depending on the waterproof structure of the electrical junction box. Is to provide an electrical junction box.

As a result of inventor's earnest research on the cause of ignition after vehicle inundation, copper power-side bus bar connected to power line and copper ground-side bus bar connected to power line, especially in electrical connection box directly connected to battery It has been found that ignition occurs at a site where the two 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 accumulates between the power-side bus bar and the ground-side bus bar, so that a short-circuit path is formed between the two, and the temperature rises to some extent. At that time, the resistance of the cuprous oxide is reduced to cause 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.

  A first aspect of the present invention includes a bus bar circuit body in which a power supply side bus bar connected to a power supply line and a plurality of bus bars including a ground side bus bar connected to the ground line are arranged on an insulating plate. In the electrical junction box, the power supply side bus bar and the ground side bus bar are arranged adjacent to each other, and one of the power supply side bus bar and the ground side bus bar is made of aluminum and the other is made of copper. .

According to this aspect, one of the power supply side bus bar and the ground side bus bar arranged adjacent to each other is made of aluminum and the other is made of copper. Therefore, even if the vehicle is inundated by a tsunami or flood and electrolysis occurs between the adjacent power supply side bus bar and ground side bus bar with a large potential difference, more highly ionized aluminum is eluted than copper. Precipitation of aluminum oxide (Al ₂ O ₃ ) is promoted, and precipitation of cuprous oxide (Cu ₂ O) is suppressed. This prevents cuprous oxide from being deposited between the adjacent power supply side bus bar and ground side bus bar, and aluminum oxide is deposited instead. Here, since aluminum oxide is non-conductive, even if aluminum oxide is deposited between the power supply side bus bar and the ground side bus bar, a short circuit is formed to prevent a short circuit. Thereby, even if it does not depend on the waterproof structure of an electrical junction box, generation | occurrence | production of the ignition of the electrical junction box at the time of flooding can be prevented with a simple structure.

  In particular, by making either one of the electric wire side bus bar and the ground side bus bar made of aluminum and the other made of copper, the volume of the entire bus bar circuit body can be suppressed while suppressing the precipitation of cuprous oxide during water immersion. Therefore, for example, in the bus bar circuit body, only one of the adjacent electric wire side bus bar and the ground side bus bar is made of aluminum, and all the other bus bars are made of copper. Without requiring a design change, it is possible to easily apply an ignition prevention structure during flooding while avoiding an increase in the size of the electrical junction box.

  The power source side bus bar includes not only those directly connected to the plus terminal of the battery as the power line but also those indirectly connected through other members. The ground-side bus bar includes not only those directly connected to the negative terminal of the battery, which is a ground line, but also those indirectly connected via other members. In short, a power supply side bus bar and a ground side bus bar are configured by two adjacently arranged bus bars having a potential difference. The aluminum bus bar refers to a bus bar formed from aluminum or an aluminum alloy, and the copper bus bar refers to a bus bar formed from copper or a copper alloy.

  A second aspect of the present invention is the one described in the first aspect, wherein the power supply side bus bar is made of copper and the ground side bus bar is made of aluminum.

  According to this aspect, the power supply side bus bar that conducts a relatively large current is made of copper having a high conductivity, and the ground side bus bar that conducts a relatively small current is made of aluminum having a low conductivity. It is possible to employ a structure that suppresses the precipitation of cuprous oxide while suppressing the body volume increase more advantageously.

  According to the present invention, one of the power supply side bus bar and the ground side bus bar arranged adjacent to each other is made of aluminum and the other is made of copper. Therefore, even if the vehicle is submerged by a tsunami or flood, aluminum having a high ionization tendency elutes more than copper, and the precipitation of aluminum oxide is promoted to suppress the precipitation of cuprous oxide. Here, since aluminum oxide is non-conductive, even if aluminum oxide is deposited between the power supply side bus bar and the ground side bus bar, a short circuit is formed to prevent a short circuit. In addition, for example, only one of the adjacent electric wire side bus bar and the ground side bus bar is made of aluminum, and all the other bus bars are made of copper, which requires a significant design change of the existing electric junction box. Therefore, it is possible to easily apply the structure for preventing ignition during flooding while avoiding the enlargement of the electrical junction box.

The disassembled perspective view which shows the electrical-connection box as one Embodiment of this invention.

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

  FIG. 1 shows an electrical junction box 10 as an embodiment of the present invention. As shown in FIG. 1, the electrical junction box 10 includes a bus bar circuit body 12, an upper case 14, and a lower case 16 that constitute an internal circuit. Then, the upper case 14 and the lower case 16 are overlapped and assembled from both sides of the bus bar circuit body 12 to provide the electrical junction 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 bus bar 28c is a power supply side bus bar connected to the power supply line, while the bus bar 28d is a ground side bus bar connected to the ground line. Here, the power supply side bus bar includes not only those directly connected to the plus terminal of the battery which is the power supply line, but also those connected indirectly through other members. The ground-side bus bar includes not only those directly connected to the negative terminal of the battery, which is a ground line, but also those indirectly connected via other members. In short, the power supply side bus bar and the ground side bus bar are constituted by two bus bars arranged adjacent to each other having a potential difference. For example, in addition to 12V, the power supply side bus bar includes a bus bar to which a voltage such as 24V or 48V is applied and a bus bar to which a voltage of 12V or less is applied. In addition to the bus bar to which a voltage of 0 V is applied, the ground-side bus bar includes a bus bar to which a voltage of 0 V or higher, which is lower than that of the power supply side bus bar, is applied. In the present embodiment, a voltage of 12V is applied to the power supply side bus bar 28c, and a voltage of 0V is applied to the ground side bus bar 28d.

As shown in FIG. 1, a power supply side bus bar 28c and a ground side bus bar 28d are disposed adjacent to each other. In the present embodiment, the power supply side bus bar 28c is made of copper made of a copper material such as copper or copper alloy, while the ground side bus bar 28d is made of aluminum made of an aluminum material such as aluminum or aluminum alloy. As a result, even if the vehicle is inundated by a tsunami or flood and electrolysis occurs between the adjacent power supply side bus bar 28c and the ground side bus bar 28d having a large potential difference, more highly ionized aluminum is eluted than copper. Thus, precipitation of aluminum oxide (Al ₂ O ₃ ) is promoted, and precipitation of cuprous oxide (Cu ₂ O) is suppressed. Therefore, aluminum oxide is deposited instead of cuprous oxide between the power supply side bus bar 28c and the ground side bus bar 28d. Here, since aluminum oxide is non-conductive, even if aluminum oxide is deposited, a short circuit is formed and short-circuiting is prevented. With the structure, it is possible to prevent the occurrence of ignition of the electrical junction box 10 at the time of flooding.

  In particular, in the present embodiment, only the ground-side bus bar 28d, which is one of the power-supply side bus bar 28c and the ground-side bus bar 28d that are adjacently disposed, is made of aluminum, and all the other bus bars are made of copper as in the prior art. As a result, the structure for preventing ignition at the time of flooding according to the present invention can be easily applied without requiring a significant design change of the existing electrical junction box, and the cost of the electrical junction box can be reduced while avoiding an increase in size. Therefore, it is possible to realize a fire prevention structure when flooded.

  Moreover, according to the present embodiment, the power supply side bus bar 28c that conducts a relatively large current is made of copper having a high conductivity, and the ground side bus bar 28d that conducts a relatively small current is made of aluminum having a low conductivity. . Therefore, the power supply side bus bar 28c can be significantly reduced in size as compared with the case where the power supply side bus bar 28c is made of aluminum. In short, by applying an aluminum bus bar, which requires an area larger than copper for energization, to the ground-side bus bar 28d, the increase in the volume of the bus bar circuit body 12 is further advantageously suppressed, and the precipitation of cuprous oxide is suppressed. It is possible to adopt a structure that can hold down.

  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 power supply side bus bar 28c is made of copper and the ground side bus bar 28d is made of aluminum, but the power supply side bus bar 28c may be made of aluminum and the ground side bus bar 28d may be made of copper.

10: Electrical connection box, 12: Bus bar circuit body, 26: Insulating plate, 28a to d: Bus bar

Claims (2)

In an electrical junction box comprising a bus bar circuit body in which a plurality of bus bars including a power source side bus bar connected to a power source line and a ground side bus bar connected to a ground line are arranged on an insulating plate,
While the power supply side bus bar and the ground side bus bar are arranged adjacent to each other,
One of the power supply side bus bar and the ground side bus bar is made of aluminum and the other is made of copper.   The electrical junction box according to claim 1, wherein the power supply side bus bar is made of copper, and the ground side bus bar is made of aluminum.

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