JP2012124032A - Shield tube and wiring harness - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a shield tube and a wiring harness which maintain shield performance, handleability and versatility by forming a metal layer in a synthetic resin tube and which are made inexpensive and also made excellent in economical efficiency.SOLUTION: In a wiring harness 1, a shield tube 2 is formed by forming a metal layer 4 on the surface of a corrugated tube at a predetermined thickness, and on the surface of the metal layer 4, a plurality of non-formation parts 5, 5 .. of the meal layer are formed in which the sum of lengths L1 is 1/12 of the entire length of the shield tube 2 or less and the length L2 in the circumferential direction is 1/2 of the whole circumference of the shield tube 2 or less.

Description

  The present invention relates to a shield tube used for imparting shielding performance to an automobile wire harness, and a wire harness using the shield tube.

  For example, electromagnetic noise due to high-frequency current is generated in a conductive wire that supplies a motor driving current to an inverter device of an electric vehicle. Therefore, a shield tube is used for a wire harness to shield the electromagnetic noise. For example, Patent Document 1 discloses a modification in which an intermediate portion of a wire harness is covered with a main shield portion made of a metal pipe, and an end portion connected to the inverter device includes a cylindrical mesh member and a connection pipe. A configuration of a shield tube covered with a possible sub-shield portion is disclosed. In Patent Document 2, a spiral connection screw portion is formed at an end portion of a metal cylindrical member covering the wire harness, and this is screwed into a female screw portion formed at an introduction portion of the connector housing. The structure of the shield pipe to be connected is disclosed. In addition, the bellows part for bending is intermittently formed between the cylindrical members, and can be arbitrarily bent along the path of the wire harness.

JP 2004-171952 A JP 2009-123461 A

Since the above conventional shield tube is made of metal, it is heavy and unhandled, and when it is installed along the floor of the vehicle, it must be attached via an attachment member such as a bracket, and the installation space is also large. It was getting bigger. In addition, since high-precision mounting is required at a fixed position, work is troublesome.
Furthermore, even if the bellows portion is provided, there is a limit in flexibility, so that application is limited to a certain vehicle type, and versatility is low.
Therefore, it is conceivable to form a metal layer on the front or back surface of a lightweight and flexible synthetic resin tube to provide a shield. However, if a metal layer is formed on the entire surface of the synthetic resin tube, the cost increases.

  Therefore, the present invention provides a shield tube and a wire harness that are low in cost and economical in addition to ensuring the shielding performance as well as maintaining the handleability and versatility by forming a metal layer on the synthetic resin tube. It is intended to provide.

In order to achieve the above object, the invention described in claim 1 is a shield tube in which a metal layer is formed with a predetermined thickness on the front surface or the back surface of a synthetic resin tube, and the surface on which the metal layer is formed has an axial direction. A plurality of non-formed portions of the metal layer are formed in which the total length of the length is 1/12 or less of the total length of the shield tube, and the total length in the circumferential direction is 1/2 or less of the total length of the shield tube It is a feature.
Here, the “total length in the axial direction” means the net portion of the overall length in the axial direction of the shield tube occupied by the non-formed portion in the axial direction. Therefore, for example, when a plurality of non-formed portions arranged in the axial direction are formed and the non-formed portions are also arranged in the circumferential direction, the axial length of each non-formed portion overlapping in the circumferential direction is not added. , Add only one axial length.
Similarly, the “total length in the circumferential direction” also means the net part of the circumferential length of the shield tube occupied by the non-formed part in the circumferential direction. Therefore, for example, when a plurality of non-formed portions arranged in the circumferential direction are formed and the non-formed portions are also arranged in the axial direction, the circumferential lengths of the respective non-formed portions overlapping in the axial direction are not added. Add only one circumferential length.
According to a second aspect of the present invention, in the configuration of the first aspect, the total length of the non-formed portions in the axial direction is 1/24 or less of the total length of the shield tube.
According to a third aspect of the present invention, in the configuration of the first or second aspect, the synthetic resin tube has a bellows structure.
In order to achieve the above object, the invention according to claim 4 is a wire harness, wherein one or a plurality of electric wires are inserted through the shield tube according to any one of claims 1 to 3. To do.

According to invention of Claim 1 and 4, a shield performance is ensured and a handleability and versatility can be maintained. Further, since the metal layer is reduced to the limit necessary for the shielding performance by the non-formed portion, the cost is reduced and the cost is excellent.
According to invention of Claim 2, in addition to the effect of Claim 1, suitable shield performance can be obtained in a wide band of 10 kHz to 1 GHz.
According to invention of Claim 3, in addition to the effect of Claim 1 or 2, it is excellent in flexibility and handling property improves.

It is a cross-sectional view of a wire harness. It is a side view of a wire harness. It is a graph which shows the shielding performance of the wire harness of Example 1. It is a graph which shows the shielding performance of the wire harness of Example 2. It is a graph which shows the shield performance of the 100 MHz-1 GHz band of the wire harness of Example 2. It is a graph which shows the shielding performance of the wire harness of a reference example. It is a graph which shows the shield performance of 100 MHz-1 GHz band of the wire harness of a reference example.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows an example of a wire harness. The wire harness 1 is formed by inserting two electric wires 3 and 3 through a cylindrical shield tube 2. As shown in FIG. 2, the shield tube 2 used here is a synthetic resin tube having a bellows structure generally called a corrugated tube. Here, a metal layer 4 is formed on the surface of the shield tube 2. The metal layer 4 is made of copper, aluminum, or the like, but is not limited to a single metal, and may be formed of a plurality of layers such as copper + tin and copper + nickel.

As a means for forming the metal layer 4 in the shield tube 2, plating is often used, but it can also be formed by vapor deposition, coating, or pressure bonding of metal foil.
Further, the thickness of the metal layer 4 is desirably 13 μm or more in order to obtain the shielding performance required for the wire harness. The upper limit of the thickness is preferably 50 μm to 80 μm in consideration of cost.

However, the metal layer 4 here is not the entire surface of the shield tube 2 but is provided with non-formed portions 5, 5. The non-forming portion 5 has a rectangular shape having a predetermined length (for example, 1 mm in both the axial direction and the circumferential direction) in the axial direction and the circumferential direction of the shield tube 2, and is spaced at predetermined intervals along the axial direction of the shield tube 2. It is formed at a plurality of locations.
Further, if the non-formed part 5 is too large, the shielding performance is deteriorated. Therefore, the total of the axial lengths L1, L1, L1,... Not overlapping in the circumferential direction of all the non-formed parts 5 is the shield tube 2. The circumferential length L2 that does not overlap in the axial direction is less than or equal to 1/2 of the entire circumference of the shield tube 2 or less. Has been.

  Therefore, according to this wire harness 1, the total length L1 in the axial direction is 1/12 or less of the total length of the shield tube 2 on the surface of the synthetic resin shield tube 2 where the metal layer 4 is formed. By forming a plurality of metal layer non-formed portions 5, 5,... Having a length L2 of ½ or less of the entire circumference of the shield tube 2, the shield performance can be ensured and the handleability and versatility can be maintained. Further, since the metal layer 4 is reduced to the limit necessary for the shielding performance by the non-forming portion 5, the cost is reduced and the cost is excellent.

In addition, the number and shape of the non-formation part of a metal layer are not restricted to the said form, Other shapes, such as circular and an ellipse, may be sufficient. However, in any case, the length in the axial direction and the circumferential direction is the maximum dimension in each direction (for example, in a circular non-formed portion, the axial dimension and the circumferential direction are calculated by the diameter dimension).
Further, the non-formed portions are not limited to being provided in a single row in the axial direction, and a plurality of rows may be provided. In the case of this plurality of rows, the total length in the axial direction is not added to the axial length of each forming portion in the non-forming portions arranged (overlapping) in the circumferential direction, but only one axial length is added. Similarly, the total length in the circumferential direction is not added to the length in the circumferential direction of each forming portion in the non-forming portions arranged (overlapping) in the axial direction, but only one circumferential length is added.

On the other hand, the shield tube is not limited to a circular cross section, and may be an oval or elliptical cross section, and the metal layer may be formed on the back surface together with the non-formed portion. In addition, when forming a metal layer on the surface, if the outer surface of the metal layer is coated with a synthetic resin or the like, the metal layer will not be exposed, and even if another electric wire or the like is in contact, the metal layer is short-circuited. Etc. are prevented.
Furthermore, the shield tube is not limited to the one having the bellows structure as a whole, and even a synthetic resin tube having a bellows structure partially at a plurality of locations or a synthetic resin tube having no bellows structure if flexible is used. There is no problem.

In addition, a slit is formed over the entire length of the synthetic resin tube in the axial direction to form a metal layer on the front surface and the back surface of one of the divided ends, and one end portion on which the metal layer is formed on the back surface A shield tube may be formed by overlapping the end portion of the shield from the outside with a predetermined overlap. According to this, insertion / removal of an electric wire becomes easy through a slit.
On the other hand, a synthetic resin pipe having a circular cross section is divided into two along its axial direction, and a metal layer is respectively provided on the surface of the obtained pair of half pipes, and a metal layer is provided on the back surface of both ends of either half pipe. The other half-divided tube from the outside of one half-divided tube may be combined in an opposing manner so that both end portions overlap each other over the entire length with a predetermined overlap allowance to obtain a shield tube. Thus, even if it divides into two, the contact state in the overlap margin is maintained by the rigidity of the half pipe, and the integrity can be maintained even if the shield pipe is bent.
In these cases, the non-formed portion may be formed at the overlapping portion, but it is desirable to form the non-formed portion at a portion other than the overlapping portion because the non-formed portion needs to be polymerized between the end portions.

  Hereinafter, specific examples will be described.

On the surface of a corrugated tube having an outer diameter of 18φ, an inner diameter of 15φ and a length of 1.2 m, a metal layer is formed by copper plating with a thickness of 30 μm, and the axial length of the metal layer is 1 mm. A plurality of non-formed parts whose circumferential length is expressed as an angle around the axis of 100 ° / 360 ° (28%) are formed at predetermined intervals so that the total axial length is 40 mm. Then, two 3 sq wires were inserted through the shield tube to create a wire harness. The result of measuring the shielding performance of the obtained wire harness is shown in FIG.
According to this measurement result, it was confirmed that a shield performance of 40 dB or more was obtained over substantially the entire band of 10 kHz to 1 GHz.

One slit is formed over the entire axial length of the corrugated tube having an outer diameter of 18φ, an inner diameter of 15φ, and a length of 1.2 mm, and the entire surface of the corrugated tube and the back surface of one end portion divided by the slit In addition, a shield layer was formed by forming a metal layer by copper plating with a thickness of 50 μm, and two 3 sq wires were inserted into the shield tube to prepare a wire harness.
Next, one end with the metal layer formed on the back surface of the shield tube is overlapped with the other end from the outside, and the axial length is 1 mm and the axial total is provided at a place other than the overlapped portion. A plurality of non-formed parts having a length of 40 mm are formed at predetermined intervals, and the circumferential length of each non-formed part is 22 ° / 360 ° (1/16 cut) to 360 ° / 360 ° at an angle around the axis. It was changed step by step within the range of (complete cut), and the shielding performance at each ratio was measured. The measurement results are shown in FIGS.

  According to this measurement result, the difference in the shielding performance becomes significant in a high frequency band of 30 MHz or more, and if the total length in the circumferential direction of the non-formed part is ½ (circumferential cut rate 50%) or less, 30 MHz. It was found that the necessary shielding performance (40 dB or more) can be obtained even in a high frequency band of ˜1 GHz.

[Reference example]
Here, the upper limit of the total axial length of the non-formed part is verified.
A slit is formed over the entire axial length of the corrugated tube having an outer diameter of 18φ, an inner diameter of 15φ, and a length of 1.2 mm. In addition, a metal layer made of copper plating with a thickness of 25 μm was formed to create a shield tube, and two 3 sq electric wires were inserted into the shield tube to create a wire harness.
Next, one end with the metal layer formed on the back surface of the shield tube is overlapped with the other end from the outside, and the total length in the axial direction of the gap formed in the thickness direction between both ends is calculated. The shield performance at each length was measured by changing stepwise in the range of 5 mm to 200 mm. The measurement results are shown in FIGS.

  According to this measurement result, the difference in shield performance becomes significant in a high frequency band of 30 MHz or more, and the total length in the axial direction of the non-formed part is 100 mm or less (1/12 or less of the total length of the shield tube) It was found that the necessary shielding performance (40 dB or more) was obtained even in the 30 MHz to 1 GHz band, and that shielding performance was obtained over the entire band if the total was 1/24 or less of the total length of the shield tube.

  1 .... Wire harness, 2 .... Shield tube, 3 .... Wire, 4 .... Metal layer, 5 .... Non-formed part, L1 .... Axial length of non-formed part, L2 .... Non-formed part Circumferential length.

Claims (4)

A shield tube in which a metal layer is formed with a predetermined thickness on the front or back surface of a synthetic resin tube,
On the surface on which the metal layer is formed, the total length in the axial direction is 1/12 or less of the total length of the shield tube, and the total length in the circumferential direction is 1/2 or less of the total circumference of the shield tube A shield tube in which a plurality of non-formed portions of the metal layer are formed.   The shield tube according to claim 1, wherein the total length of the non-formed portions in the axial direction is 1/24 or less of the total length of the shield tube.   The shield tube according to claim 1 or 2, wherein the synthetic resin tube has a bellows structure.   A wire harness, wherein one or a plurality of electric wires are inserted through the shield tube according to any one of claims 1 to 3.

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