JP2014096930A - Grounding structure of electrical junction box - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a grounding structure of an electrical junction box, capable of reducing impedance between a ground electrode of an electrical junction box and ground.SOLUTION: In the grounding structure of an electrical junction box which connects an electrical junction box mounted on a vehicle to ground, a ground electrode of a substrate provided in the electrical junction box is provided with a connection terminal 12, and a braided wire 13 is routed between the connection terminal 12 and the ground. Since impedance between a filter circuit and the ground is reduced with such a configuration, noise superimposed on a power supply line routed in the electrical junction box can be effectively removed.

Description

  The present invention relates to a grounding structure when an electrical connection box mounted on a vehicle is grounded, and particularly relates to a technique for reducing impedance.

  In an electrical connection box such as a relay box (R / B) or a junction box (J / B) mounted on a vehicle, a filter circuit having a capacitor is provided in order to prevent the influence of noise. The filter circuit has one end connected to a power supply line (or signal line) and the other end connected to the ground via a ground line. Then, noise superimposed on the power supply line (or signal line) is removed.

  FIG. 6 is an explanatory view showing a conventional J / B 101, in which a ground wire 103 is connected to one terminal of a connector portion 104 mounted on the J / B 101, and further, a ground terminal is connected to the tip of the ground wire 103. 102 is fixed by crimping or the like, and the ground terminal 102 is connected to a ground such as a vehicle body. FIG. 7 is an equivalent circuit diagram of the filter circuit. As shown, the power supply line L1 is grounded via a capacitor C1 and a ground line 103.

  In such a conventional grounding structure of the electrical junction box, if the impedance of the ground wire 103 is high, the noise reduction effect by the filter circuit is lowered.

  As a method of connecting to the ground with low impedance, for example, Patent Document 1 describes a flexible bus bar made of a braided wire. However, Patent Document 1 is intended to prevent depression due to bolt tightening, and is not intended to reduce impedance.

JP 2008-41330 A

  As described above, in the conventional ground structure of the electrical junction box, the filter effect is reduced when the impedance of the ground line 103 connecting the filter circuit and the ground is higher than that of the corresponding load line. There is a problem of end up. That is, the connector unit 104 is intended to connect the signal line and does not consider connecting the ground line of the filter circuit. Therefore, the impedance is relatively smaller than the impedance of the corresponding load line. It will be high. Further, a normal harness is used as the ground line 103, and the impedance of this ground line is also relatively high, and the impedance between the capacitor C1 and the ground shown in FIG. The effect is reduced. For this reason, there is a problem that noise superimposed on the power supply line L1 shown in FIG. 7 cannot be effectively removed.

  The present invention has been made to solve such a conventional problem, and an object of the present invention is to provide an electrical connection capable of reducing the impedance between the ground electrode of the electrical junction box and the ground. It is to provide a grounding structure for a box.

  In order to achieve the above object, an invention according to claim 1 of the present application provides a grounding structure of an electrical junction box for grounding an electrical junction box mounted on a vehicle to the ground. A connection portion is provided, and a ground wire made of a low impedance material is routed between the connection portion and the ground.

  The invention according to claim 2 further includes a bus bar that conducts from the vicinity of the center of the substrate to the end portion of the substrate, and the connection portion is connected to a front end of the bus bar.

  The invention according to claim 3 is characterized in that a copper core layer is provided in an intermediate layer of the substrate, the ground electrode is connected to the copper core layer, and the connection portion is provided in the copper core layer.

  The invention according to claim 4 is characterized in that the grounding wire made of the low impedance material is a braided wire.

  The invention according to claim 5 is characterized in that the ground line is provided between a capacitor used as a filter circuit and a ground.

  In the first aspect of the invention, since the ground electrode of the electrical junction box and the ground are connected by the ground line made of a low impedance material, the power junction box is provided when a filter circuit is provided inside the electrical junction box. The noise superimposed on the power supply line or signal line connected to can be surely escaped to the ground and removed.

  In the invention of claim 2, since the bus bar that conducts from the vicinity of the center of the substrate to the end of the substrate is provided, the impedance of the ground wire can be further reduced, and the noise removal effect can be further enhanced.

  In the invention of claim 3, since the copper core layer is provided in the intermediate layer of the substrate and the connection portion is provided in the copper core layer, the impedance from the filter circuit to the ground can be reduced.

  In the invention of claim 4, since the braided wire having a low impedance is used as the ground wire, the impedance of the ground wire can be reduced.

  In the invention of claim 5, since the ground line is provided between the capacitor used as the filter circuit and the ground, the noise removal effect by the filter circuit can be improved.

It is a perspective view which shows the structure of the electrical junction box by which the grounding structure of the electrical junction box which concerns on 1st Embodiment of this invention is employ | adopted. It is sectional drawing of the board | substrate provided in the inside of the electrical junction box by which the grounding structure of the electrical junction box which concerns on 1st Embodiment of this invention is employ | adopted. It is sectional drawing of the board | substrate provided in the inside of the electrical junction box by which the grounding structure of the electrical junction box which concerns on 2nd Embodiment of this invention is employ | adopted. It is sectional drawing of the board | substrate provided in the inside of the electrical junction box by which the grounding structure of the electrical junction box which concerns on 3rd Embodiment of this invention is employ | adopted. It is explanatory drawing which shows the connection state of the braided wire used for the grounding structure of the electrical junction box which concerns on embodiment of this invention. It is explanatory drawing which shows the structure of the conventional electrical junction box. It is an equivalent circuit diagram of a filter circuit.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a perspective view showing an electrical junction box employing a ground structure according to a first embodiment of the present invention. In the present embodiment, the case where the electrical junction box is a junction box (J / B) 11 that is mounted on a vehicle and branches a power supply line or a signal line will be described.

  As shown in FIG. 1, a connection terminal 12 (connection portion) connected to the ground electrode of the J / B 11 is provided at an appropriate position on the upper surface of the J / B 11. In addition, a braided wire 13 (low impedance ground wire) is provided to connect the connection terminal 12 to a ground such as a vehicle body. A metal socket 19 is provided at one end of the braided wire 13. A round terminal 14 is provided on the other end side.

  As shown in FIG. 5, the socket 19 has a rectangular fitting portion at the tip, and a braided wire is fixed to the socket 19 by soldering or crimping. And the braided wire 13 and the connection terminal 12 can be connected so that attachment or detachment is possible by fitting the fitting part of the socket 19 to the connection terminal 12. FIG. The round terminal 14 is fixed to a ground such as a vehicle body.

  FIG. 2 is a cross-sectional view of the substrate 15 provided inside the J / B 11. As shown in FIG. 2, a wiring pattern 17 serving as a ground electrode is provided in the intermediate layer of the substrate, and one terminal 18b of a capacitor 16 (for example, a film capacitor) is connected to the wiring pattern 17. ing. The other terminal 18a of the capacitor 16 is connected to a power supply line (not shown). Furthermore, the wiring pattern 17 is connected to a terminal 18 c that is the tip of the connection terminal 12 in the intermediate layer of the substrate 15.

  Accordingly, the capacitor 16 is disposed between the power supply line and the ground, and the terminal 18 b on the ground side of the capacitor 16 is connected via the wiring pattern 17, the connection terminal 12, and the braided wire 13. It will be connected to the ground such as the body of the vehicle.

  At this time, the braided wire 13 has a lower impedance than a normal wiring harness, and the connection terminal 12 and the socket 19 are connected with an extremely low impedance. As a result, the impedance of the ground line connecting the capacitor 16 and the ground can be reduced as compared with the case where the connector portion 104 of FIG. 6 shown in the conventional example and the ground wire 103 made of a normal harness are used. . Therefore, the noise superimposed on the power supply line can be released to the ground by the filter circuit composed of the capacitor 16, and the noise superimposed on the power supply line can be effectively removed.

  In this manner, in the grounding structure for the electrical junction box according to the first embodiment of the present invention, the impedance of the grounding wire can be lowered, so that reliable noise removal is possible.

  Next, a second embodiment of the present invention will be described. FIG. 3 is a cross-sectional view of the substrate 15a provided inside the electrical junction box in which the ground structure according to the second embodiment of the present invention is adopted. Similar to FIG. 2 described above, a wiring pattern 17 is provided in the intermediate layer of the substrate 15 a, and a terminal 18 b on the ground side of the capacitor 16 is connected to the wiring pattern 17. Further, a bus bar 20 is connected to the wiring pattern 17 through a terminal 18d.

  The bus bar 20 is arranged so as to extend in the direction of the end portion of the substrate 15a, and the connection terminal 12 is provided at the tip portion thereof. The connection terminal 12 is connected to the socket 19. Therefore, the capacitor 16 is disposed between the power supply line and the ground, and the terminal 18b on the ground side of the capacitor 16 is connected via the wiring pattern 17, the bus bar 20, and the braided wire 13. It is connected to the ground such as the body of the vehicle.

  In the second embodiment, since the bus bar 20 conducts from the vicinity of the center of the substrate 15a to the end of the substrate, the impedance can be further reduced as compared with the first embodiment described above. As a result, noise superimposed on the power supply line can be more effectively removed.

  Next, a third embodiment of the present invention will be described. FIG. 4 is a cross-sectional view of a substrate 15b provided inside an electrical junction box that employs a grounding structure according to a third embodiment of the present invention. In the third embodiment, the copper core layer 21 is provided in the intermediate layer of the substrate 15b. A terminal 18 b on the ground side of the capacitor 16 is connected to the copper core layer 21. Further, a connection terminal 22 is provided at the tip of the copper core layer 21, and the connection terminal 22 is connected to a socket 19 attached to the tip of the braided wire 13.

  Therefore, the capacitor 16 is disposed between the power supply line and the ground, and the terminal 18b on the ground side of the capacitor 16 is connected to the vehicle via the copper core layer 21 and the braided wire 13. It will be connected to the ground such as the body.

  In the third embodiment, by using the copper core layer 21, the impedance from the terminal 18b of the capacitor 16 to the round terminal 14 can be lowered. As a result, noise superimposed on the power supply line can be effectively removed.

  As mentioned above, although the grounding structure of the electrical junction box of the present invention has been described based on the illustrated embodiment, the present invention is not limited to this, and the configuration of each part is of an arbitrary configuration having the same function Can be replaced.

  For example, in each of the embodiments described above, J / B has been described as an example of the electrical connection box. However, the present invention is not limited to this, and can be applied to other electrical connection boxes such as a relay box. It is possible.

  Further, in each of the above-described embodiments, the example in which the braided wire is used as the ground wire made of the low impedance material has been described. It is.

  The present invention can be used to effectively remove noise superimposed on a power supply line.

DESCRIPTION OF SYMBOLS 12 Connection terminal 13 Braided wire 14 Round terminal 15 Board | substrate 15a Board | substrate 15b Board | substrate 16 Capacitor 17 Wiring pattern 18a, 18b, 18c, 18d Terminal 19 Socket 20 Bus bar 21 Copper core layer 22 Connection terminal 102 Ground terminal 103 Ground wire 104 Connector part

Claims (5)

In the grounding structure of the electrical junction box that grounds the electrical junction box mounted on the vehicle to the ground,
Providing a connection portion on the ground electrode of the substrate provided in the electrical connection box;
A grounding structure for an electrical junction box, wherein a grounding wire made of a low impedance material is routed between the connecting portion and the ground.   2. The grounding structure for an electrical connection box according to claim 1, further comprising a bus bar that conducts from the vicinity of the center of the substrate to an end portion of the substrate, wherein the connection portion is connected to a front end of the bus bar.   2. The electrical junction box according to claim 1, wherein a copper core layer is provided on an intermediate layer of the substrate, the ground electrode is connected to the copper core layer, and the connection portion is provided on the copper core layer. Grounding structure.   The grounding structure for an electrical junction box according to any one of claims 1 to 3, wherein the grounding wire made of the low impedance material is a braided wire.   The grounding structure for an electric junction box according to any one of claims 1 to 4, wherein the grounding wire is provided between a capacitor used as a filter circuit and a ground.

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