JP2009214631A - Power supply connection structure of vehicular shielded line - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electric wire offering high shielding performance, which can be routed in a vehicle interior without the need for being routed under the floor of a vehicle body. <P>SOLUTION: A power supply connection structure includes a shielded line including a core wire constituted by covering a conductor with an insulating covering layer, a shield layer comprising a metal braid tube covering the core wire, and a sheath made of an insulating resin covering the shield layer, and is configured, with the conductor of the core wire connected to the positive side of a power supply and the shield layer connected to the negative side thereof, such that a positive-side current path of the core wire and a negative-side current path of the shield layer are identical in axis and flow currents in parallel but opposite directions so that the magnetic field generated at the shield layer cancels the magnetic field generated at the conductor of the core wire to prevent the core wire's magnetic field from being discharged to the outside. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a power connection structure for a shielded wire for an automobile, and in particular, prevents a magnetic field generated from a core wire of the shielded wire from leaking to the outside.

  A large current flows in a power line connecting the battery and the inverter in the electric vehicle or the hybrid vehicle, a power line connecting the battery and the motor for driving the wheel, a conventional starter motor electric wire of the gasoline vehicle, and the like. For this reason, when there is an electric wire connected to an electronic device or an electronic circuit at a position close to these electric wires, the magnetic field generated from the electric wire with a large change in current amount becomes noise with respect to the adjacent electric wire, It is necessary to shield reliably.

For example, as an electric wire having a function of shielding a magnetic field to the outside, in a high-voltage wire harness disclosed in Japanese Patent Laid-Open No. 2006-156051 (Patent Document 1), as shown in FIG. A metal protector 2 is put on the outer periphery of the electric wire 1, and a shielded electric wire covered with a metal braided tube is used as the electric wire 3 in the routing route requiring flexibility, so that electromagnetic noise does not leak outside.
The electric wire that covers the metal protector 2 is composed of a power wire for underfloor wiring that connects a battery and an inverter in an electric vehicle or a hybrid vehicle. The power wire has a large amount of current change, and is compared with the electric wire that is wired inside the vehicle. Generates large noise. In order to prevent the noise from affecting the electronic devices and electric wires connected to the electronic circuit, a power line is wired under the floor to secure a distance from the electronic device and the electronic circuit and to shield it with a sheet metal of the vehicle body. Further, in order to perform wiring under the floor, the metal protector 2 is covered so as to protect the power supply line from external interference materials such as gravel and the like.

  However, when the metal protector 2 or the metal pipe is used, there is a problem from the viewpoint of improving the fuel consumption because the cost is increased and the mounting workability to the vehicle is deteriorated and the weight of the automobile is increased. In addition, when an electric wire is routed outside the vehicle body below the floor sheet metal, the length of the electric wire is longer than when the wire is routed inside the vehicle body. From this viewpoint, it is desired to develop a shielded electric wire that has higher electromagnetic wave shielding performance than a conventional shielded wire, does not have a large electric wire diameter, and does not change the flexibility and weight of the electric wire.

  In Japanese Patent Application Laid-Open No. 2006-312409 (Patent Document 2), similarly to Patent Document 1, the shield conductor is arranged under the floor of the vehicle body, but this is caused by the current flowing in the conductor path that is an electric wire. This is because the generated magnetic field cannot be sufficiently shielded by the shield conductor wire.

JP 2006-156051 A JP 2006-312409 A

  The present invention has been made in view of the above problems, and it is an object of the present invention to provide an electric wire with high shielding performance that can be routed in a vehicle without having to route the under floor of the vehicle body.

In order to solve the above-mentioned problems, the present invention is a connection structure between a shielded wire and a power source arranged in an automobile,
A core wire in which a conductor is covered with an insulating coating layer, a shield layer made of a metal braided tube that covers the core wire, and a shield wire that has a sheath made of an insulating resin that covers the shield layer,
The conductor of the core line is connected to the positive side of the power supply, the shield layer is connected to the negative side of the power supply, and the central axis of the positive current path of the core line and the central axis of the negative current path of the shield layer Are the same, the positive current and the negative current flow in the opposite direction in parallel, and the positive current amount and the negative current amount are the same,
A power supply connection structure for an automotive shielded wire is provided, wherein the magnetic field generated by the current flowing through the conductor of the core wire is canceled by the magnetic field generated by the current flowing through the shield layer.

  In the shield wire in which the outer periphery of the core wire is covered with a shield layer made of a metal braided tube, and the outer periphery of the shield layer is covered with a sheath made of an insulating resin layer, the shield layer is the outer periphery of the insulating cover layer of the core wire having a circular cross section Therefore, the central axis of the conductor of the core wire and the central axis of the shield layer coincide with each other. In this way, since the central axis of the shield layer and the conductor of the core wire are coincident, it is generated from the core wire by passing a negative current through the shield layer in the opposite direction to the positive current passing through the core wire. And the magnetic field generated from the shield layer cancel each other, and the leakage magnetic field generated outside from the shield wire can be made almost zero.

In this way, the magnetic field generated from the conductor of the core wire is canceled out by the magnetic field generated from the shield layer simply by connecting the shield layer to the negative side of the power supply and flowing it in the direction opposite to the positive current flowing through the conductor of the core wire. Thus, the shield wire can be prevented from becoming a magnetic field generation source. Therefore, the magnetic field can be greatly reduced as compared with the shield wire in which the conventional shield layer is simply connected to the ground, and noise due to the magnetic field with respect to the electric wire wired in the proximity position can be reduced or eliminated. For this reason, it is not necessary to isolate the wires from other wires and to wire under the floor or the like, and it is not necessary to cover them with metal pipes or protectors required for underfloor wiring.
In addition, because it is structurally the same as the conventional shielded wire, it does not increase in weight and has the same flexibility, so that it can be handled easily and is easy to attach to a vehicle, and the degree of freedom in routing can be improved. it can. For this reason, as described above, it is not necessary to take a detour route called underfloor wiring, and the routing route can be made the shortest, thereby reducing cost and weight.

  In addition, since the positive current amount and the negative current amount are the same, if the current amount flowing through the core wire and the shield layer is the same, the magnetic fields cancel each other and the external magnetic field generated from the power supply line is almost zero. It can be. Therefore, the noise can be made almost zero with respect to other electric wires wired in close positions.

  The shield wire of the present invention may be a coaxial cable made of one core wire, or may be a shield wire surrounding a plurality of core wires with a shield layer made of one metal braided tube. In a shield wire having a plurality of core wires, The central axis surrounded by the core line is made to coincide with the central axis of the shield layer.

Both ends of the metal braided tube of the shield layer are drawn out from the ends of the core wire and the sheath, a terminal is connected to the lead-out end, one terminal is connected to the negative side of the power source, and the other terminal is a negative load It is preferable to be connected to a side circuit.
Thus, by connecting both ends of the metal braided tube, the same and reverse current flows in the conductor of the core wire and the shield layer, so that the induction of the electric field to the external device is prevented. it can.

The shield layer made of the metal braided tube may be provided with a plurality of flanges on the outer peripheral surface in the circumferential direction and extended in the axial direction to increase the surface area and enhance the heat dissipation function.
Thus, by providing a collar part in a metal braided tube, since the surface area of a metal braided tube becomes large and heat dissipation can be improved, the temperature rise by heat_generation | fever of a conductor can be suppressed. Therefore, when it is desired to reduce the cross-sectional area of the conductor as much as possible, it is preferable to provide a flange on the metal braided tube because the amount of heat generation increases.
Even if the metal braided tube is provided with a flange, the central axis of the metal braided tube is made to coincide with the central axis of the conductor of the core wire.

The shield wire of the present invention is used as a power supply line for connecting the battery and the inverter and a power supply line for connecting the battery and the wheel driving motor. Is routed inside the car body.
As described above, the shielded wire of the present invention can greatly reduce the magnetic field to be leaked, and in principle can be reduced to zero, and does not give noise to the electric wire arranged in the close position. There is no need to route the wires, and the wires can be wired on the floor in the vehicle body where wiring of the wires is easy.

As described above, according to the present invention, in a shielded wire that is used for a large current and has a large change in current value, the shield layer is connected to the minus side of the power source and is opposite to the plus side that flows through the conductor of the core wire. By energizing in the direction, the magnetic field generated from the conductor is canceled out by the magnetic field generated in the shield layer, so that the magnetic field can be greatly reduced or zero compared to the conventional shielded wire.
Therefore, since it does not become a magnetic field generation source, it is not necessary to wire under the floor and cover the power line with a metal pipe or metal protector, etc., and it is possible to reduce the weight, and the metal pipe and metal protector for each vehicle type as in the past. There is no need to create. Furthermore, since wiring in the passenger compartment is possible, the routing route can be made the shortest.
In addition, because it is structurally similar to the conventional shielded wire, there is no increase in weight and flexibility is the same, so it is easy to handle and attachable to the vehicle, and improves the freedom of routing. Therefore, cost reduction and weight reduction can be achieved.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
1 to 3 show a first embodiment of the present invention.
As shown in FIG. 1, the automotive shield wire 10 of the present invention is a power line 10 that connects the battery B and the inverter I of the hybrid vehicle 20, and is wired inside the vehicle body on the upper side of the floor sheet metal.

As shown in FIG. 2, the power supply line 10 includes a single core wire 13 in which a conductor 11 having a circular cross section is covered with an insulating coating layer 12, and a shield layer formed of a metal braided tube 14 that covers the core wire 13. And a shield wire made of a coaxial line provided with a sheath 15 made of an insulating resin covering the metal braided tube 14.
The central axis P1 of the metal braided tube 14 of the shield layer attached in contact with the outer peripheral surface of the core wire 13 coincides with the central axis P2 of the conductor 11 of the core wire.

  One end of the conductor 11 of the core wire 13 is connected to the positive side of the battery B, while one end of the metal braided tube 14 of the shield layer is connected to the negative side of the battery B. A plus-side current and a minus-side current flow in parallel in the braided tube 14, and a plus-side current in the conductor 11 flows in the X direction as shown in FIG. 2, and a minus-side current in the metal braided tube 14 in the Y direction. Flow, reverse direction.

  Specifically, as shown in FIG. 3, both ends 11a and 11b of the conductor 11 of the core wire 13 are pulled out from the sheath 15 and the insulating coating layer 12 and are crimped to the terminals 21a and 21b, and one terminal 21a is connected to the battery. While connecting to the positive side of B, the other terminal 21b is connected to the positive side of the inverter I.

The metal braided tube 14 covered over the entire length of the core wire 13 is drawn out on both sides in the length direction, and terminals 22a and 22b are crimped and connected to the drawn ends 14a and 14b. One terminal 22a is connected to the negative side of the battery B, while the other terminal 22b is a ground terminal and is connected to the negative side of a load (not shown).
From the battery B, the positive energizing amount for energizing the conductor 11 and the minus energizing amount for energizing the metal braided tube 14 of the shield layer have the same current value.

When the shield wire is connected to the battery B as described above, the metal braided tube 14 and the conductor 11 of the core wire 13 are on the same axis P1 and P2, and a reverse current flows at the same current value. The leakage magnetic field generated and the leakage magnetic field generated from the metal braided tube 14 cancel each other, so that the magnetic field leaking from the conductor 11 can be reduced, and can be zero in principle.
It should be noted that one end of the metal braided tube 14 serving as the shield layer may be grounded to the vehicle body panel so that the potential of the shield layer is zero.

  Therefore, even if the power supply line 10 is not a magnetic field generation source and it is wired indoors, it is possible to prevent noise caused by the magnetic field from being applied to the adjacent electric wires. Therefore, as shown in FIG. A power line connecting the battery and the inverter can be wired indoors.

FIG. 4 shows a second embodiment of the present invention.
In the power supply line 30 of the present embodiment, three core electric wires 33 </ b> A to 33 </ b> C are covered with one metal braided tube 14.
It arrange | positions so that the line which connects center axis line P3-P5 of each core electric wire 33A-33C may become an equilateral triangle. The axis P6 and the center axis P1 of the metal braided tube 14 that are equidistant from the center axes P3 to P5 of the conductors 31A to 31C of the three core electric wires 33A to 33C are the same axis. One terminal of the metal braided tube 14 is connected to the negative battery as in the first embodiment. The other terminal is connected to the negative side of three loads to which three core wires are connected.
The energization amount to the metal braided tube 14 is a current value equivalent to the total value of the energization amounts to the respective conductors of the three core wires 33A to 33C.

  With the above configuration, similarly to the first embodiment, reverse currents flow in parallel with the same current value, so that the magnetic field generated from the conductors of the three core wires 33A to 33C is generated from the metal braided tube 14. The magnetic field that is canceled out by the magnetic field and leaks from the power supply line 10 can be made substantially zero.

The number of core wires is not limited to three, and if a plurality of core wires are evenly arranged in the circumferential direction, the central axis of the metal braided tube 14 and the central axis surrounded by the plurality of core wires are made the same. As described above, the magnetic field from the power supply line 10 can be made substantially zero.
Since other configurations and operational effects are the same as those of the first embodiment, the same reference numerals are given and description thereof is omitted.

FIG. 5 shows a third embodiment of the present invention.
The shield layer made of the metal braided tube 34 is attached in a shape having a flange 34 a on the outer peripheral surface of the insulating coating layer of the core wire 13. The flange portions 34a are provided uniformly at intervals in the circumferential direction and are provided so as to extend in the axial direction. In the present embodiment, six hooks 34a are provided in the circumferential direction.
Similarly to the first and second embodiments, the metal braided tube 34 has one end connected to the negative side of the battery and the other end connected to the negative side of the load.

With the above configuration, since the metal braided tube 34 has a large surface area and can improve heat dissipation, when the amount of heat generated by the conductor 11 of the core wire 14 is large, the metal braided tube 34 can dissipate heat, The temperature rise of the wire 10 can be suppressed.
Note that the number of hooks is not limited to six, and the magnetic field from the power supply line 10 can be made substantially zero if the height of the hooks is equal at intervals close to the circumferential direction.
Since other configurations and operational effects are the same as those of the first embodiment, the same reference numerals are given and description thereof is omitted.

It is a figure which shows the wiring path | route of a hybrid vehicle. It is a figure which shows the power wire of 1st Embodiment, (A) is a perspective view, (B) is sectional drawing of an axial direction, (C) is sectional drawing of an orthogonal direction with an axial direction. It is the figure which showed the both ends of the power wire. It is sectional drawing which shows the power wire of 2nd Embodiment. It is a perspective view which shows the power wire of 3rd Embodiment. It is a figure which shows a prior art example.

Explanation of symbols

10 Automotive shielded cable (power cable)
11 Conductor 12 Insulation coating layer 13 Core wire 14 Metal braided tube 14a, 14b Lead end 15 Sheath 22a, 22b Terminal B Battery I Inverter

Claims (5)

A connection structure between a shielded wire and a power source that are routed in an automobile,
A core wire in which a conductor is covered with an insulating coating layer, a shield layer made of a metal braided tube that covers the core wire, and a shield wire that has a sheath made of an insulating resin that covers the shield layer,
The conductor of the core line is connected to the positive side of the power supply, the shield layer is connected to the negative side of the power supply, and the central axis of the positive current path of the core line and the central axis of the negative current path of the shield layer Are the same, the positive current and the negative current flow in the opposite direction in parallel, and the positive current amount and the negative current amount are the same,
A power supply connection structure for an automotive shielded wire, wherein a magnetic field generated by a current flowing through a conductor of the core wire is canceled by a magnetic field generated by a current flowing through the shield layer.   The shield wire is a coaxial cable made of a single core wire, or a shield wire surrounding a plurality of core wires with a shield layer made of a single metal braided tube, and the shield wire having the plurality of core wires is surrounded by the core wire. The power connection structure for a shielded wire for automobiles according to claim 1, wherein a central axis to be aligned with a central axis of the shield layer.   Both ends of the metal braided tube of the shield layer are pulled out from the ends of the core wire and the sheath, a terminal is connected to the lead-out end, one terminal is connected to the negative side of the power source, and the other terminal is a negative load. The power supply connection structure of the shielded wire for automobiles according to any one of claims 1 and 2, wherein the power supply connecting structure is connected to a side circuit.   The shield layer made of the metal braided tube is provided with a plurality of flange portions on the outer peripheral surface in the circumferential direction and extended in the axial direction, and has a large surface area to enhance the heat radiation function. The power supply connection structure of the shield wire for motor vehicles of any one.   The shield wire is a power line connecting the battery and the inverter and a power line connecting the battery and the wheel driving motor. The power supply connection structure of the shield wire for motor vehicles of any one of Claim 1 thru | or 4 currently wired in.

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