JP2014094660A - Wiring structure of electrical junction box for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wiring structure of an electrical junction box which can avoid influence on operation of a low impedance load by noise.SOLUTION: A wiring structure of electric wires for a J/B 11 (electrical junction box) which divides a power source line connected with a vehicle power line into at least three systems and supplies work loads connected with respective systems with electric power, wires the electric wires L1-L4 so that an electric wire L1 connected with a work load 21 where noise occurs most frequently among work loads 21-24 of a plurality of systems and an electric wire L2 connected with a work load 22 where impedance is lowest among work loads 21-24 except the work load 21 are not adjacent to each other. Thereby, noise is prevented from routing to the electric wire L2 connected with the lowest impedance work load, and malfunction caused by noise is avoided.

Description

  The present invention relates to a routing structure when routing an electric wire in an electrical junction box mounted on a vehicle.

  An electrical junction box (junction box; hereinafter abbreviated as “J / B”) mounted on a vehicle branches and outputs power lines connected to a battery into a plurality of systems (for example, see Patent Document 1). FIG. 3 is a circuit diagram showing a conventional J / B 100 and a plurality of loads 21 to 24 connected to the J / B. And a relay 101 for switching between connection and disconnection of the electric wire connected to the power supply terminal T1. Furthermore, the rear stage side of the relay 101 is branched into a plurality of systems (four systems in FIG. 3) of electric wires L1 to L4, and the electric wires L1 to L4 are connected to the load connection terminals T2 to T5. Each of the load connection terminals T2 to T5 is connected to the loads 21 to 24 via a harness. Further, fuses F1 to F4 for protecting the circuit when an overcurrent occurs are connected to the electric wires L1 to L4.

  The loads 21 to 24 are loads mounted on the vehicle such as a lamp, a motor, an airbag ECU, an ignition, and a wiper. Here, for example, the ignition generates a large noise at the time of start-up, so that there is a problem that the noise is superimposed on a low impedance load electric wire arranged in the vicinity thereof.

  For example, when the load 21 shown in FIG. 3 is an ignition and the load 22 adjacent to the load 21 is a low impedance load such as an airbag ECU or a navigation unit, noise generated by the ignition (load 21) is reduced. The electric power is transmitted from the electric wire L1 to the electric wire L2 of the load 22 via the path indicated by the arrow Y1 in the figure, and the low impedance load 22 is adversely affected. For example, when the low impedance load 22 is an airbag ECU, electromagnetic waves due to noise are radiated to the surroundings in a circuit connected to a noise filter provided in the airbag ECU. There may be a problem that the smart key installed in the passenger compartment malfunctions.

JP 2011-105205 A

  As described above, in a conventional electrical junction box routing structure, a load that generates a lot of noise and a low impedance load may be arranged close to each other in the J / B100 (electric junction box). In such a case, there has been a problem that the generated noise is transmitted to the low impedance load side to adversely affect the operation of the low impedance load.

  The present invention has been made to solve such a conventional problem, and an object of the present invention is to arrange an electrical junction box that can avoid the influence of noise on the operation of a low impedance load. To provide a cable structure.

  In order to achieve the above object, the invention described in claim 1 of the present application is an electrical connection box for branching a power line connected to a vehicle power source into at least three systems and supplying power to a load connected to each system. In the wiring structure of the electric wire, the electric wire (L1) connected to the first load that generates the most noise among the loads of a plurality of systems and the second load having the lowest impedance excluding the first load The electric wire is routed so that the electric wire (L2) is not adjacent.

  The invention described in claim 2 is characterized in that the wiring connected to the second load is made redundant.

  According to a third aspect of the present invention, the electrical junction box further includes at least two external connection terminals, and the electric wire connected to the second load is routed outside the electrical junction box and the two external connections. A loop wire (L11) that short-circuits between the connection terminals is included.

  In the first aspect of the invention, since the first load and the second load are not adjacent to each other, the electric wires connected to each load are routed with a large interval. Therefore, it is possible to prevent the noise generated in the first load from entering the electric wire connected to the second load, and to avoid the problem that the first load having a low impedance malfunctions due to the influence of noise. it can.

  In the invention of claim 2, since the wiring (L2) connected to the second load is made redundant, the impedance can be increased by the redundant amount, and as a result, noise is transmitted to the second load. Can be prevented.

  In the invention of claim 3, since the electric wire connected to the second load is routed to the outside of the electrical connection box using the external connection terminal, the impedance can be further increased, and the noise is transmitted to the second load. Can be prevented.

It is a circuit diagram showing the wiring structure of the electric junction box for vehicles concerning a 1st embodiment of the present invention. It is a circuit diagram which shows the wiring structure of the electrical-connection box for vehicles which concerns on 2nd Embodiment of this invention. It is a circuit diagram which shows the wiring structure of the conventional electrical junction box for vehicles.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[Description of First Embodiment]
FIG. 1 is a circuit diagram showing a wiring structure of an electric junction box for a vehicle according to a first embodiment of the present invention. As shown in FIG. 1, the electrical junction box 11 (hereinafter abbreviated as “J / B”) according to the first embodiment includes a power supply terminal T1 connected to a power supply line 31 of a vehicle battery, and the power supply terminal T1. And a relay 12 connected to.

  Furthermore, the rear stage side of the relay 12 is branched into a plurality of systems (in this example, 4 systems), which are connected to the load connection terminals T2 to T5 via the electric wires L1 to L4, respectively. T5 is connected to loads 21 to 24, respectively. The load 21 is a load (first load) that generates a lot of noise such as an ignition or a wiper, for example. The load 22 is a low impedance load (second load) such as an airbag ECU or a navigation unit. It is. The loads 23 and 24 are high impedance loads such as motors and lamps. And in J / B11 which concerns on this embodiment, the electric wires L1, L4, L3, and L2 are connected to the load connection terminals T2 to T5, respectively. Accordingly, the loads 21 to 24 are arranged in the order of the loads 21, 24, 23, and 22.

  Furthermore, the electric wire L2 connected to the load 22 which is a low impedance load is routed in a redundant (circular) manner inside the board provided in the J / B 11.

  Next, the operation of the routing structure according to the present embodiment configured as described above will be described. In the present embodiment, as shown in FIG. 1, among the loads 21 to 24 of a plurality of systems, the electric wire L1 connected to the load 21 that generates the most noise and the load 22 other than the load 21 are connected to the load 22 having the lowest impedance. The electric wires L1 to L4 are routed so as not to be adjacent to the electric wire L2. That is, the wires L1 and L2 are routed so as to be the farthest from each other. Furthermore, the electric wire L2 connected to the load 22 is wired redundantly.

  Accordingly, the distance of the electric wire L2 through which the noise generated in the load 21 is transmitted to the load 22 side, which is a low impedance load, becomes longer compared to the conventional case, and as a result, the impedance of the electric wire L2 becomes larger than the conventional value. It becomes large and it becomes difficult to transmit noise to the load 22 side. That is, the noise generated in the load 21 is transmitted to the load 22 side through the path indicated by the arrow Y2 in FIG. 1, and the impedance of this path is longer than the path indicated by the arrow Y1 in FIG. Is set. As a result, a low impedance load such as an airbag ECU is not easily affected by noise.

  Thus, in the wiring structure of the electric junction box for vehicles according to the first embodiment, the electric wire L1 connected to the load 21 that generates the noise most among the four loads 21 to 24 and the lowest impedance. Since the wires L1 to L4 are routed on the substrate so as not to be adjacent to the wire L2 connected to the load 22, the impedance of the wire L2 increases, and noise generated in the wire L1 wraps around the wire L2. Can be prevented.

  Therefore, it is possible to prevent the low impedance load from malfunctioning due to the influence of noise as in the prior art, and to prevent the emission of electromagnetic waves caused by noise. For this reason, it is possible to avoid the occurrence of problems such as malfunction of electronic devices such as smart keys provided in the passenger compartment due to the influence of electromagnetic waves.

[Description of Second Embodiment]
Next, a second embodiment of the present invention will be described. FIG. 2 is a circuit diagram showing a wiring structure of the electric junction box for a vehicle according to the second embodiment. The wiring structure shown in FIG. 2 is substantially the same as the wiring structure shown in FIG. 1 described above, but the point that the external connection terminals T11 and T12 are provided, and the loop electric wire L11 is connected to the external connection terminals T11 and T12. It differs in that it is routed.

  That is, in the J / B (electrical connection box) 11a according to the second embodiment, the electric wire L2 connected to the load 22 which is a low impedance load is divided into electric wires L2a and L2b, and among these, the electric wire L2a is the external connection terminal T11. The electric wire L2b is connected to the external connection terminal T12. In addition, as described above, the two external connection terminals T11 and T12 are short-circuited by the loop electric wire L11. Further, the loop electric wire L11 has a certain length and is routed so as to pass through another substrate or the like.

  And in the routing structure which concerns on 2nd Embodiment comprised in this way, noise will be transmitted along arrow Y3 shown in FIG. For this reason, since the electric wire for connecting to the load 22 which is a low impedance load is the total distance of L2a, L11, and L2b and the wiring distance is set longer than in the conventional case, noise is generated in the load 21. When this occurs, this noise can be prevented from wrapping around the load 22 via the electric wires L1, L2a, L11, and L2b. As a result, it is possible to prevent the load 22 from malfunctioning due to the influence of noise and emitting electromagnetic waves.

  Moreover, since the loop electric wire L11 is routed outside the substrate of the J / B 11a and made redundant, the resistance value of the electric wire can be further increased as compared with the first embodiment, and noise wraps around. Can be effectively suppressed.

  As mentioned above, although the wiring structure of the electrical junction box for vehicles of this invention was demonstrated based on embodiment of illustration, this invention is not limited to this, The structure of each part is arbitrary which has the same function. It can be replaced with a configuration one.

  For example, in the first and second embodiments described above, the example in which the J / Bs 11 and 11a are branched into four systems has been described. In the first and second embodiments described above, the example in which the load 21 that generates the most noise and the load 22 having the lowest impedance are arranged so as to be the farthest from each other has been described. The position of the load 23 shown in FIG. 2 (position not adjacent to the load 21) can also be used.

  In the first and second embodiments, the example in which the electric wires L2 (L2a, L2b) connected to the load 22 are made redundant has been described. However, it is only necessary to move the wiring positions of the electric wires L1 and L2 away from the electric wires L2. If the impedance can be increased, the electric wires L2 can be routed without making them redundant.

  The present invention is extremely useful in preventing noise from entering a low impedance load when connecting electric wires to a plurality of loads.

11 Electrical connection box 12 Relay 21 Load (first load; load that generates noise)
22 load (second load; low impedance load)
23, 24 Load 31 Power supply line L1-L4 Electric wire L11 Loop electric wire F1-F4 Fuse T1 Power supply terminal T2-T5 Load connection terminal T11, T12 External connection terminal

Claims (3)

In the wiring structure of the electric connection box for supplying power to the load connected to each system, branching the power line connected to the vehicle power source into at least three systems,
The electric wires are connected so that the electric wires connected to the first load that generates the most noise among the loads of the plurality of systems and the electric wires connected to the second load having the lowest impedance excluding the first load are not adjacent to each other. A wiring structure of an electric junction box for a vehicle, characterized by wiring.   The wiring structure for an electric junction box for a vehicle according to claim 1, wherein wiring for connecting to the second load is made redundant.   The electric connection box further includes at least two external connection terminals, and the electric wire connected to the second load is routed outside the electric connection box and short-circuits between the two external connection terminals. The wiring structure of the electric junction box for vehicles according to claim 2 characterized by things.

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