JP2020155242A - Wire Harness - Google Patents

Abstract

To provide a wire harness capable of securing heat release property and space saving, and improving shield performance.SOLUTION: A wire harness comprising a flat shield layer for including a single cable or a plurality of cables, the flat shield layer is configured so that, a layer thickness on a part which is close to a center position of an AC current density flowing to a cable is greater than a layer thickness on a part which is separated from the center position of the AC current density flowing to the cable. The flat shield layer comprises long sides and short sides on a periphery of a cross section along a width direction, a layer thickness on the long side is greater than an average layer thickness of whole flat shield layer and a layer thickness on the short side is smaller than the average layer thickness.SELECTED DRAWING: Figure 1

Description

The present invention relates to a wire harness, and is particularly suitable for application to a shielded wire harness.

Conventionally, flat cables have high heat dissipation, so they have a large current capacity and the cross-sectional area of the wires can be reduced compared to round wires, which reduces the weight of wire harnesses and space for wiring, especially low profile. It is expected to become a product. In particular, the application of flat cables to high-voltage harnesses used in high-voltage, high-current environments is expected. However, high-voltage harnesses have been shielded by aluminum pipes and braids because electromagnetic induction noise due to large currents is regarded as a problem. For example, Patent Documents 1 and 2 describe a wire harness housed in a protective material and in which a flat flat cable is arranged inside a shield layer such as a metal braid. Patent Document 3 describes a wire harness in which laminated flat cables are shielded.

Japanese Unexamined Patent Publication No. 2011-134667 Japanese Unexamined Patent Publication No. 2012-235666 Japanese Unexamined Patent Publication No. 2014-128130

Here, when a flat cable is used for the wire harness or round wires are used side by side, there arises a problem that the shield circumference becomes long when shielding them. Also, when flat cables and round wires are used side by side, the aspect ratio defined by the length of the long side to the length of the short side is large in the cross section of the shield, unlike the shield of the round pipe used in the case of the round wire. Become. As a result, there arises a problem that the shield current density decreases at the corners and short side portions of the shield, and the shield performance deteriorates. Therefore, it is conceivable to shorten the peripheral length of the shield by stacking a plurality of flat cables, but on the contrary, the advantages of the flat cables such as heat dissipation and space saving will be impaired.

The present invention has been made in view of the above, and an object of the present invention is to provide a wire harness capable of improving shielding performance while ensuring heat dissipation and space saving.

In order to solve the above-mentioned problems and achieve the above-mentioned object, the wire harness according to the present invention is a wire harness provided with a flat shield layer including a single cable or a plurality of cables, and the flat shield layer is the said. The layer thickness of the portion of the AC current density flowing through the cable that is close to the center position is larger than the layer thickness of the portion of the AC current density flowing through the cable that is far from the center position.

In the above invention, the wire harness according to one aspect of the present invention has a long side and a short side at the circumference of a cross section along the width direction, and the layer thickness on the long side side is large. It is characterized in that it is larger than the overall average layer thickness of the flat shield layer and the layer thickness on the short side side is smaller than the average layer thickness.

The wire harness according to one aspect of the present invention is characterized in that, in the above invention, the aspect ratio of the long side to the short side is 3 or more and 30 or less.

In the above invention, in the wire harness according to one aspect of the present invention, a plurality of the cables are arranged in parallel in the width direction and included in the flat shield layer, and between the plurality of cables in the flat shield layer. The layer thickness of the portion covering the flat shield layer is larger than the layer thickness of the flat shield layer other than the portion covering between the plurality of cables.

In the wire harness according to one aspect of the present invention, in the above invention, the layer thickness of the portion having the largest layer thickness in the flat shield layer is 2 times or more and 10 times or less the layer thickness of the portion having the smallest layer thickness. It is characterized by being.

The wire harness according to one aspect of the present invention is a wire harness provided with a flat shield layer containing a single cable or a plurality of cables, and is a distance from the center position of the alternating current density flowing through the cables in the flat shield layer. A drain wire that is shielded and grounded independently of the flat shield layer is provided on the outer surface of the portion close to the flat shield layer.

In the above invention, in the wire harness according to one aspect of the present invention, a plurality of the cables are arranged in parallel in the width direction and included in the flat shield layer, and the drain wire is formed on the outer surface of the flat shield layer. It is characterized in that it is provided in a portion that covers between each of a plurality of cables.

In the wire harness according to one aspect of the present invention, in the above invention, the sum of the layer thickness of the flat shield layer and the layer thickness of the drain wire is the layer thickness of the portion where the layer thickness of the flat shield layer is the smallest. It is characterized in that it is 2 times or more and 10 times or less.

The wire harness according to one aspect of the present invention is characterized in that, in the above invention, the layer thickness of the flat shield layer is 0.08 mm or more and 1 mm or less.

According to the wire harness according to the present invention, since the effective cross section of the portion where the current density of the shield current is high can be increased, it is possible to improve the shield performance while ensuring heat dissipation and space saving.

FIG. 1 is a cross-sectional view taken along the width direction showing a wire harness according to the first embodiment of the present invention. FIG. 2 is a cross-sectional view taken along the width direction showing the wire harness according to the second embodiment of the present invention. FIG. 3 is a cross-sectional view taken along the width direction showing the wire harness according to the third embodiment of the present invention. FIG. 4 is a cross-sectional view taken along the width direction showing the wire harness according to the fourth embodiment of the present invention. FIG. 5 is a cross-sectional view taken along the width direction showing the wire harness according to the fifth embodiment of the present invention. FIG. 6 is a cross-sectional view taken along the width direction showing the wire harness according to the sixth embodiment of the present invention. FIG. 7 is a cross-sectional view taken along the width direction showing a wire harness according to the prior art. FIG. 8 is a graph showing the frequency characteristics of noise in the wire harness. FIG. 9 is a cross-sectional view taken along the width direction in which the flat cable according to the first modification of the present invention shows two wire harnesses. FIG. 10 is a cross-sectional view taken along the width direction in which the flat cable according to the second modification of the present invention shows two wire harnesses.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In all the drawings of the following embodiments, the same or corresponding parts are designated by the same reference numerals. Further, the present invention is not limited to the embodiments described below.

First, before explaining the embodiment of the present invention, the diligent study conducted by the present inventor will be described. That is, since the flat cable has high heat dissipation, it has a large current capacity, and the cross section of the electric wire can be reduced as compared with the round wire, which contributes to weight reduction of the wire harness and space saving at the time of wiring. Therefore, it is conceivable to construct a wire harness which is a high voltage harness by using a flat cable. However, in high-voltage harnesses, electromagnetic induction noise due to a large current (hereinafter referred to as noise) becomes a problem, so it is shielded by an aluminum pipe or braid.

FIG. 7 is a cross-sectional view taken along the width direction showing a wire harness according to the prior art. As shown in FIG. 7, the flat cable 1 is configured by covering the periphery of a conductor 2 having a flat shape with a coating 3. The conductor 2 is composed of, for example, a core wire formed by twisting a plurality of strands of about 40 wires. Each wire is, for example, an aluminum wire and is made of high-purity aluminum or an aluminum alloy. The conductor 2 is an aggregate of stranded wires in which a plurality of stranded wires composed of a plurality of strands are arranged in the width direction, an aggregate of strands in which a plurality of strands are arranged in the width direction, and a flat conductor such as a flat conductor. A single wire having a different shape may be used. The coating 3 is made of an insulating resin such as polyvinyl chloride (PVC), polyethylene (PE), or a non-halogen material. An additive such as a plasticizer may be added to the resin constituting the coating 3. The flat cable 1 has a flat cross section (hereinafter referred to as a cross section in the width direction) along the width direction perpendicular to the longitudinal direction.

The wire harness 100 according to the prior art is a shielded flat wire harness contained in a flat shield layer 101 for the flat cable 1 to impart a shielding property. The flat shield layer 101 is composed of a braid or a pipe made of a material capable of conducting an electric current such as aluminum (Al) or copper (Cu). The flat shield layer 101 shown in FIG. 7 has a substantially rectangular cross section in the width direction. A predetermined clearance is provided between the flat cable 1 and the flat shield layer 101. Further, the layer thickness of the flat shield layer 101 in the cross section in the width direction is substantially constant along the circumferential direction.

When the flat cable 1 is used for the wire harness 100, the peripheral length of the flat shield layer 101 (2 × (A + B) in the example shown in FIG. 7) when shielding the flat cable 1 becomes long. Further, in the flat shield layer 101 provided so as to cover the flat cable 1, the aspect ratio (A / B) defined by the width A, which is the horizontal length, becomes larger than the thickness B, which is the vertical length. Due to these factors, the shield current density decreases at the corners and short sides of the flat shield layer 101, which may reduce the shield performance. In addition, the current and current distribution flowing through the flat shield layer 101, the ground resistance of the flat shield layer 101, and the like also affect the noise.

In this regard, the present inventor has conducted various studies. That is, the present inventor applies a high-voltage / large-current alternating current to the wire harness 100 by changing the frequency in the range of 10 kHz to 1 GHz to obtain a current density distribution of the flat cable 1 and the flat shield layer 101. It was measured. In the measured current density distribution, the present inventor has found that in a square shield such as the flat shield layer 101, the shield current tends to concentrate on the long side. The present inventor has focused on the fact that the shield current easily flows on the long side of the flat shield layer 101, and the shield current does not easily flow on the short side, especially on the corners. First, from Ampere's law (H = I / 2πr, H: magnetic field, I: current, r: distance), the electromagnetic induction noise in the wire harness 100 is a function of distance. Therefore, the shield performance is improved by increasing the cross section on the long side of the flat shield layer, particularly the cross section of the portion where the shield current tends to concentrate, and increasing the effective cross section that contributes to the shield current. I came up with that.

In addition, the present inventor has measured the frequency dependence of noise when an alternating current is applied to the wire harness 100 in a frequency range of 10 kHz to 1 GHz. The result is shown in FIG. FIG. 8 is a graph showing the frequency dependence of noise (dBm). From FIG. 8, it can be seen that when the frequency of the alternating current is 1 MHz or more when the alternating current is applied to the wire harness 100, the noise increases sharply. From this point, the present inventor has conceived that it is preferable to increase the effective cross section in which the shield current flows in the portion where the shield current tends to concentrate when the frequency of the alternating current is 1 MHz or more. The present inventor conducted a more specific study on the method that was conceived, and proposed that the layer thickness of the portion of the AC current density flowing through the flat cable near the center position be larger than the layer thickness of the portion far away. I put it out. As a result, the thickness of the shield layer in the portion where the current density of the shield current is low can be reduced, so that the weight of the wire harness can be reduced. The embodiments described below have been devised based on the above diligent studies.

(First Embodiment)
The wire harness according to the first embodiment of the present invention will be described. FIG. 1 shows a wire harness according to the first embodiment. As shown in FIG. 1, the wire harness 10 according to the first embodiment is configured by including a single flat cable 1 in a flat shield layer 11. The flat cable 1 has the same configuration as the conventional flat cable 1 described above. As shown in FIG. 1, when there is one flat cable 1, the center position P of the alternating current density is the cross-sectional center of the flat cable 1. Therefore, in the flat shield layer 11, the layer thickness of the portion where the distance from the center position of the AC current density flowing through the flat cable 1 is short is larger than the layer thickness of the portion where the distance from the center position of the AC current density is long. It is configured in. In other words, when the flat cable 1 is energized with an alternating current in the frequency band of 1 MHz or higher, the layer thickness of the portion where the current density of the shield current is high is configured to be larger than the layer thickness of the portion where the current density is low. Has been done. Here, the high current density means that the local current density in the width direction cross section of the flat shield layer 11 is higher than the average current density of the shield current flowing through the flat shield layer 11. On the contrary, low current density means that the local current density in the widthwise cross section of the flat shield layer 11 is lower than the average current density of the shield current flowing through the flat shield layer 11.

The flat shield layer 11 has a substantially rectangular shape having a long side and a short side on the circumference of the cross section in the width direction. The flat shield layer 11 is composed of a braid or a pipe made of a material capable of conducting an electric current such as Al or Cu. In the flat shield layer 11, on the long side side (hereinafter, long side side) of the flat cable 1, the layer thickness of the cross section in the width direction is directed from both sides along the width direction (x direction in FIG. 1) toward the substantially central portion. Is configured to increase. In other words, the widthwise cross-sectional shape of the flat shield layer 11 on the long side is a mountain shape such that the top portion 11a is located at a portion where the current density of the shield current is high. As a result, the layer thickness on the long side becomes larger than the overall average layer thickness of the flat shield layer 11, while the layer thickness on the short side becomes smaller than the average layer thickness. Here, it is preferable that the top portion 11a of the flat shield layer 11 is provided at a portion corresponding to the center position P of the AC current density flowing through the flat cable 1 when viewed from the thickness direction (y direction in FIG. 1).

The layer thickness D of the flat shield layer 11 can be variously different depending on the use of the wire harness 10, but it is preferably 0.08 mm or more and 1 mm or less in consideration of use in a vehicle or the like. In the flat shield layer 11, the layer thickness D ₁ at the top portion 21a where the layer thickness D is the maximum is typically _{2 with} respect to the layer thickness D ₂ on the corner portion and the short side where the layer thickness D is the minimum. It is fold or more and 10 times or less, preferably 3 times or more and 8 times or less, and more preferably 3 times or more and 4 times or less. In the flat shield layer 11 provided so as to cover the flat cable 1, the aspect ratio (A / B) of the width A to the thickness B, that is, the aspect ratio (A / B) of the wire harness 10 is preferably 3 or more and 30 or less. ..

The layer thickness on the short side of the flat shield layer 11 is configured to be substantially constant. Since the current density of the shield current is small on the short side of the flat shield layer 11, the layer thickness on the short side of the flat shield layer 11 is less than the layer thickness of the top 11a, preferably the average of the layer thicknesses on the long side. It is preferable to configure it as follows. Further, the flat shield layer 11 according to the first embodiment is provided so that the inner surface is close to the outer surface of the flat cable 1. As a result, the size of the wire harness 10 can be reduced.

(Measurement method and measurement conditions for shield performance)
Next, the measuring method and the measuring conditions of the shield performance will be described. The shield performance is measured by the absorption clamp method (CISPR 16-1-3). Here, the terminating resistance is 50Ω, the housing resistance is 2mΩ, and the measurement frequency is 10 kHz to 1 GHz. The shield performance (dB) is a value obtained by subtracting the noise generated when the flat shield layer 11 is provided from the noise generated when the flat shield layer 11 is not provided. That is, the higher the numerical value, the higher the shielding performance of the flat shield layer 11, and the greater the shielding effect. As a criterion for determining the shield performance, it is not possible when the shield performance is 20 dB or less in all frequency bands, it is possible to exceed 20 dB and less than 30 dB, and 30 dB or more is excellent.

The sample wire harness 10 has the following conditions.
The flat cable 1 is a flat twisted electric wire under the following conditions.
Conductor 2: A two-layer structure in which the cross-sectional area in the width direction is 11 mm ² (11 sq), the core wire is an aluminum (Al) wire, and φ6.0 × 40 strands are twisted.
Coating 3: Thickness is 1 mm, and the material is cross-linked polyethylene.
Dimensions: The long side of the cross section in the width direction is 12 mm, the short side is 1.2 mm, the flatness is 10, and the length is 1 m.

The flat shield layer 11 as a sample has the following conditions.
Structure: Square aluminum pipe shield with the shape shown in Fig. 1.
Dimensions: The thickness of the thinnest part is 0.1 mm, the thickness of the thickest part is 1 mm, and the length is 1 m.
Resistance value: Shield resistivity is 3nΩ ・ m, shield resistance and each shield ground resistance are 15mΩ or less.

Based on the above-mentioned measurement method and measurement conditions of the shield performance, the shield performance of the wire harness 10 according to the first embodiment and the conventional wire harness 100 as a comparative example were measured. As a result, it was confirmed that the shield performance of the conventional wire harness 100 was 20 dB or less, whereas the shield performance of the wire harness 10 according to the first embodiment was more than 20 dB and 50 dB or less.

According to the first embodiment described above, the layer thickness of the portion of the flat shield layer 11 that is close to the center position P of the AC current density flowing through the flat cable 1 is set from the center position P of the AC current density. The effective cross-sectional area of the flat shield layer 11 even when the flat cable 1 that can realize heat dissipation and space saving is used for the wire harness 10 by making it larger than the layer thickness of the distant portion. Can be increased to improve the shielding performance.

(Second Embodiment)
Next, the wire harness according to the second embodiment will be described. FIG. 2 shows a wire harness according to the second embodiment. As shown in FIG. 2, unlike the wire harness 10 according to the first embodiment, the wire harness 20 according to the second embodiment has a predetermined position between the inner surface of the flat shield layer 21 and the outer surface of the flat cable 1. There is a clearance. As a result, when manufacturing the wire harness 20, the flat cable 1 can be easily inserted into the inner surface side of the flat shield layer 21.

Further, the flat shield layer 21 has a mountain-shaped cross-sectional shape on the long side in the width direction so that the top portion 21a is located at a portion where the current density of the shield current is high. Also in the second embodiment, the top portion 21a of the flat shield layer 21 is provided at a portion corresponding to the center position P of the AC current density flowing through the flat cable 1 when viewed from the thickness direction (y direction in FIG. 2). Is preferable. Other configurations are the same as in the first embodiment.

According to the second embodiment, the widthwise cross-sectional shape of the flat shield layer 21 on the long side is a mountain shape in which the top portion 21a is located at a portion where the current density of the shield current is high. The same effect as the morphology can be obtained.

(Third Embodiment)
Next, the wire harness according to the third embodiment will be described. FIG. 3 shows a wire harness according to the third embodiment. As shown in FIG. 3, the wire harness 30 according to the third embodiment is configured by including a single flat cable 1 in a flat shield layer 31. In the flat shield layer 31, the layer thickness D _{1 of the} portion where the distance from the center position of the AC current density flowing through the flat cable 1 is short is larger than the layer thickness D _{2 of the} portion where the distance from the center position of the AC current density is long. It is configured to be. In other words, the flat shield layer 31 is a layer in which the layer thickness D _{1 of the} portion where the current density of the shield current is high when the flat cable 1 is energized with an alternating current in the frequency band of 1 MHz or more is the layer where the current density is low. It is configured to be larger than the thickness D ₂ .

That is, the flat shield layer 31 is provided with a convex portion 32 at a substantially central portion along the width direction (x direction in FIG. 3) on the long side side. In other words, the widthwise cross-sectional shape of the flat shield layer 31 on the long side is a stepped shape such that the convex portion 32 is located at a portion where the current density of the shield current is high. The convex portion 32 of the flat shield layer 31 is preferably provided at a portion corresponding to the central position P of the AC current density flowing through the flat cable 1 when viewed from the thickness direction (y direction in FIG. 3).

The layer thickness D of the flat shield layer 31 is 0.08 mm or more and 1 mm or less. In the flat shield layer 31, the layer thickness D ₁ of the convex portion 32 is typically twice or more and 10 times or less with respect to the layer thickness D ₂ on the corner portion or the short side where the layer thickness D is the minimum. , Preferably 3 times or more and 8 times or less, and more preferably 3 times or more and 4 times or less. Further, the flat shield layer 31 according to the third embodiment is provided so that the inner surface is close to the outer surface of the flat cable 1. As a result, the size of the wire harness 30 can be reduced. Other configurations are the same as in the first embodiment.

According to the third embodiment, the convex portion 32 is provided in the substantially central portion on the long side side of the flat shield layer 31, and the convex portion 32 is located in the portion where the current density of the shield current is high. Therefore, the same effect as that of the first embodiment can be obtained.

(Fourth Embodiment)
Next, the wire harness according to the fourth embodiment will be described. FIG. 4 shows a wire harness according to the fourth embodiment. As shown in FIG. 4, in the wire harness 40 according to the fourth embodiment, a plurality of flat cables 1a, 1b, 1c in the example shown in FIG. 4 are arranged in the width direction (x direction in FIG. 4). They are adjacent and arranged in parallel. The wire harness 40 is configured to be included in the flat shield layer 41 so that the flat cables 1a, 1b, and 1c do not overlap each other. In the fourth embodiment, the wire harness 40 can be arranged between, for example, an inverter (not shown) mounted on a vehicle and a three-phase AC motor (not shown). In this case, the wire harness 40 supplies the U-phase, V-phase, and W-phase three-phase alternating currents output from the inverter to the three-phase alternating current motor. That is, the flat cables 1a, 1b, and 1c can be energized with three-phase alternating currents of U-phase, V-phase, and W-phase, respectively.

The flat cables 1a, 1b, and 1c are configured such that the circumferences of the flat conductors 2a, 2b, and 2c are covered with insulating coatings 3a, 3b, and 3c, respectively. That is, the flat cables 1a, 1b, and 1c have the same structure as the flat cable 1 described above, and have a flat cross section in the width direction.

As shown in FIG. 4, when energizing a three-phase alternating current to the flat cable 1 a to 1 c, the center position P _1, P ₂ of the alternating current density becomes a position between each of the flat cables 1 a to 1 c. Therefore, the flat shielding layer 41, the layer thickness D _11, D ₁₂ parts a short distance from the center position P _1, P ₂ of the alternating current density flowing through the flat cable 1a~1c is, the AC current density center position P ₁ , P ₂ is configured to be larger than the layer thickness D _{2 in the} far part. In other words, in the flat shield layer 41, the layer thicknesses D ₁₁ and D _{12 of the} portion where the current density of the shield current is high when a three-phase alternating current in the frequency band of 1 MHz or more is energized are the portions where the current density is low. It is configured to be larger than the layer thickness D ₂ . That is, in the flat shield layer 41, the convex portion 42 is provided so as to cover the portion between the flat cables 1a and 1b along the width direction on the long side. Further, in the flat shield layer 41, a convex portion 43 is provided so as to cover a portion between the flat cables 1b and 1c along the width direction on the long side side. In other words, the cross-sectional shape in the width direction on the long side of the flat shield layer 41 is a stepped shape such that the convex portions 42 and 43 are located in the portions where the current density of the shield current is high. Each protrusion 42, 43 of the flat shielding layer 41, (in FIG. 4, y-direction) the thickness direction as viewed from the respective portion corresponding to the center position P ₁ of the alternating current flowing flat cable 1a, the 1b, and It is preferable to cover the portion corresponding to the center position P ₂ of the alternating current flowing through the flat cables 1b and 1c.

The layer thickness of the flat shield layer 41 is 0.08 mm or more and 1 mm or less. In the flat shield layer 41, the layer thickness D ₁₁ of the convex portion 42 and the layer thickness D ₁₂ of the convex portion 43 are typical with respect to the layer thickness D ₂ on the corner portion and the short side where the layer thickness D is minimized, respectively. It is 2 times or more and 10 times or less, preferably 3 times or more and 8 times or less, and more preferably 3 times or more and 4 times or less. Further, the flat shield layer 41 according to the fourth embodiment is provided so that the inner surface is close to the outer surface on the long side side of the flat cables 1a, 1b, 1c. As a result, the size of the wire harness 40 can be reduced. As a result, the size of the wire harness 40 can be reduced. Other configurations are the same as those of the first and third embodiments.

According to the fourth embodiment, in the portion on the long side of the flat shield layer 41, the cross-sectional shape in the width direction on the long side of the flat shield layer 41 is a convex portion 42, 43 in the portion where the current density of the shield current is high. Since the stepped shape is such that each of the above is located, the same effect as that of the first to third embodiments can be obtained.

(Fifth Embodiment)
Next, the wire harness according to the fifth embodiment will be described. FIG. 5 shows a wire harness according to the fifth embodiment. As shown in FIG. 5, in the wire harness 50 according to the fifth embodiment, as in the fourth embodiment, a single unit or a plurality of, for example, three flat cables 1a, 1b, 1c are adjacent to each other in the width direction. They are arranged in parallel so as not to overlap each other, and are included in the flat shield layer 51. In the wire harness 50, for example, the flat cables 1a, 1b, and 1c can be energized with three-phase alternating currents of U-phase, V-phase, and W-phase, respectively.

On the long side of the flat shield layer 51, the layer thickness is configured to be substantially constant along the width direction (x direction in FIG. 5). Similarly, also on the short side of the flat shield layer 51, the layer thickness is configured to be substantially constant along the thickness direction (y direction in FIG. 5). Further, the wire harness 50, the flat cable 1a, 1b, the center position P _1, the drain line 4a on the outer surface of the portion a short distance from P ₂ of the alternating current density flowing in 1c, 4b, 4c, 4d is arranged There is. In other words, when the flat cables 1a to 1c are energized with a three-phase alternating current in the frequency band of 1 MHz or more, the drain wires 4a to the drain wires 4a to the positions corresponding to the portions of the flat shield layer 51 where the current density of the shield current becomes high. 4d is arranged. The drain wires 4a to 4d can also be referred to as shield wires. The drain wires 4a to 4d are configured by covering the periphery of the flat conductors 5a, 5b, 5c, and 5d with insulating coatings 6a, 6b, 6c, and 6d, respectively. When the conductors 5a to 5d are individually coated with an insulating coating, the coatings 6a to 6d may not be provided. The drain wires 4a to 4d are installed in a shield grounded state independently of the flat shield layer 51, respectively. In this case, the layer thickness of the portion that contributes to the energization of the shield current is the sum of the layer thickness d ₁ of the flat shield layer 51 and the thickness d ₂ of the conductors 5a to 5d of the drain wires 4a to 4d (d ₁ + d _2). )become. That is, it is equivalent to increasing the substantial layer thickness of the flat shield layer 51 by the thickness d _{2 of the} conductors 5a to 5d.

The drain wires 4a and 4c are respectively arranged with respect to the flat shield layer 51 on the outer surface along the width direction on the long side side and so as to cover the portion between the flat cables 1a and 1b. Further, the drain wires 4b and 4d are arranged with respect to the flat shield layer 51 so as to cover the portion between the flat cables 1b and 1c along the width direction on the long side side. In other words, on the long side side of the flat shield layer 51, the shape of the outer circumference of the cross section in the width direction is a stepped shape such that the drain lines 4a to 4d are respectively located in the portions where the current density of the shield current is high. Each drain line 4a~4d, when viewed from the thickness direction, each part corresponding to the center position P ₁ of the alternating current flowing flat cable 1a, the 1b, and the respective centers of the alternating current flowing flat cable 1b, and 1c It is preferable to provide so as to cover the portion corresponding to the position P ₂ .

The layer thickness of the flat shield layer 51 is 0.08 mm or more and 1 mm or less. The layer thickness (d ₁ + d ₂ ) of the portion that contributes to the energization of the shield current is typically _{2 with} respect to the layer thickness D ₂ on the corner or short side where the layer thickness of the flat shield layer 51 is minimized. It is fold or more and 10 times or less, preferably 3 times or more and 8 times or less, and more preferably 3 times or more and 4 times or less. Other configurations are the same as in the fourth embodiment.

According to the fifth embodiment, on the outer surface of the portion on the long side side of the flat shield layer 51, the portion where the distance from the center positions P ₁ and P _{2 of the} AC current densities flowing through the flat cables 1a, 1b, 1c is short. By providing the drain wires 4a to 4d, the actual layer thickness of the shield in the portion having a high current density can be increased as compared with the portion in which the current density is low in the flat shield layer 51. The same effect as that of the embodiment can be obtained.

(Sixth Embodiment)
Next, the wire harness according to the sixth embodiment will be described. FIG. 6 shows a wire harness according to the sixth embodiment. As shown in FIG. 6, in the wire harness 60 according to the sixth embodiment, a plurality of round wire cables 7a, 7b, 7c in the example shown in FIG. 6 are in the width direction (x direction in FIG. 6). It is arranged in parallel adjacent to. The round wire cables 7a, 7b, and 7c are configured by coating the circumferences of the round conductors 8a, 8b, and 8c with insulating coatings 9a, 9b, and 9c, respectively. The wire harness 60 is configured such that round wire cables 7a, 7b, and 7c are arranged in parallel and included in a flat shield layer 61. In the wire harness 60, for example, the round wire cables 7a, 7b, and 7c can be energized with three-phase alternating currents of U-phase, V-phase, and W-phase, respectively.

In the flat shield layer 61, the layer thickness D _{1 of the} portion where the current density of the shield current is high when the round wire cables 7a, 7b, 7c are energized with an alternating current in the frequency band of 1 MHz or more has a low current density. It is configured to be larger than the layer thickness D _{2 of the} portion. That is, in the flat shield layer 61, the convex portion 62 is provided so as to cover the portion between the round wire cables 7a and 7b along the width direction on the long side. Further, in the flat shield layer 61, a convex portion 63 is provided so as to cover a portion between the round wire cables 7b and 7c along the width direction on the long side side. In other words, the cross-sectional shape in the width direction on the long side of the flat shield layer 61 is a stepped shape in which the convex portions 62 and 63 are respectively located in the portions where the current density of the shield current is high. Portions each projecting portion 62 and 63 of the flat shielding layer 61, which (in FIG. 6, y-direction) thickness direction as viewed from, respectively corresponding to the central position P ₁ of the alternating current flowing round cables 7a, to 7b, It is preferable to cover the portion corresponding to the center position P ₂ of the alternating current flowing through the round wire cables 7b and 7c.

The layer thickness of the flat shield layer 61 is 0.08 mm or more and 1 mm or less. In the flat shield layer 61, the layer thickness D ₁₁ of the convex portion 62 and the layer thickness D ₁₂ of the convex portion 63 are typical with respect to the layer thickness D ₂ on the corner portion and the short side where the layer thickness D is minimized, respectively. It is 2 times or more and 10 times or less, preferably 3 times or more and 8 times or less, and more preferably 3 times or more and 4 times or less. Other configurations are the same as those of the first and third embodiments.

According to the sixth embodiment, in the portion on the long side of the flat shield layer 61, the cross-sectional shape in the width direction on the long side of the flat shield layer 61 is convex to the portion where the current density of the shield current is high. Since the stepped shape is such that each of the above is located, the same effect as that of the first to sixth embodiments can be obtained.

Although the embodiments of the present invention have been specifically described above, the present invention is not limited to the above-described embodiments, and various modifications based on the technical idea of the present invention are possible. For example, the numerical values given in the above-described embodiment are merely examples, and different numerical values may be used if necessary.

In the second embodiment described above, the outer surface of the flat shield layer 21 on the long side is configured to have a mountain shape, but the inner surface of the flat shield layer 21 on the long side is configured to have a mountain shape. You may.

Further, in the first to third embodiments described above, a filler obtained by filling and curing a liquid resin may be filled between the flat cable 1 and the flat shield layers 11, 21, 31. Further, in the fourth and fifth embodiments described above, a liquid resin is filled and cured between the flat cables 1a, 1b and 1c and between the flat cables 1a, 1b and 1c and the flat shield layers 41 and 51. The filler may be filled. Similarly, in the sixth embodiment, a liquid resin is filled and cured between the round wire cables 7a, 7b, 7c and between the round wire cables 7a, 7b, 7c and the flat shield layer 61. The agent may be filled. When the air gap inside the wire harness is filled with the filler, the air layer does not exist, so that the heat conduction is improved and the heat dissipation is improved.

Further, in the first to sixth embodiments described above, a protective material may be further provided on the outer periphery of the wire harnesses 10, 20, 30, 40, 50, 60. As the protective material, a corrugated tube or the like can be used, and a thermoplastic resin or the like is used as the material, preferably a polyamide resin or a polypropylene resin or the like.

In the above-described embodiment, the shape of the cross section in the width direction of the flat shield layers 11,21,31,41,51,61 is substantially rectangular, but it is a so-called non-circular shape such as an elliptical shape or a rounded rectangular shape. There may be.

In the first to sixth embodiments described above, one flat cable 1 and three flat cables 1a to 1c have been described, but the number of flat cables 1, 1a to 1c is not limited to these, and the width is not limited thereto. Two or four or more may be used as long as they are adjacent to each other in the direction and arranged in parallel so as not to overlap each other.

9 and 10 are cross-sectional views taken along the width direction showing the wire harnesses 40A and 40B having the two flat cables 1a and 1b according to the first modification and the second modification, respectively. As shown in FIGS. 9 and 10, in the wire harnesses 40A and 40B, it is assumed that two flat cables 1a and 1b arranged adjacent to each other in the width direction and arranged in parallel so as not to overlap each other are shielded. The reference numerals shown in FIGS. 9 and 10 are based on the reference numerals used in the fourth embodiment.

(First modification)
As shown in FIG. 9, the flat cable 1a, when the direction of the AC current flowing in 1b is opposite to each other, the center position P ₁ of the current density is located between the flat cable 1a, 1b. Therefore, the shielding performance of the wire harness 40A can be effectively improved by thickening the flat shield layer 41 at a portion close to the center position P ₁ of the current density and providing the convex portion 42 having a large layer thickness D _11. ..

(Second modification)
As shown in FIG. 10, when the direction of the alternating current flowing flat cable 1a, and 1b is the same direction, the center position P _1, P ₂ of the current density are located on both outer sides of the flat cable 1a, 1b. Therefore, the flat shield layer 41 at the portion where the distance from the center positions P ₁ and P _{2 of} the current density is short is thickened, and the convex portions 42 and 43 having large layer thicknesses D ₁₁ and D ₁₂ are provided, respectively. Further, in the wire harness 40B, it is preferable that the layer thickness D ₂ on the short side where the distance from the center positions P ₁ and P ₂ of the current density is short is as thick as the layer thicknesses D ₁₁ and D ₁₂ . With the above configuration, the shielding performance of the wire harness 40B can be effectively improved.

Further, in general, in adjacent flat cables 1a, 1b, 1c and the like, the phases of the alternating currents flowing through them are often different from each other, so that the flat shield layers 11,21,31,41,51,61 (hereinafter, hereinafter, The long side of 11 etc.) is close to the center positions P, P ₁ , P ₂ , P ₃ , and P ₄ of the current density. Therefore, for each of the flat shield layers 11 and the like, the layer thickness on the long side side is set to a uniform layer thickness larger than the overall average layer thickness of the flat shield layer 11 and the like, that is, a substantially uniform layer thickness, and the layer thickness on the short side side is set. May be a uniform layer thickness smaller than the average layer thickness. With such a configuration, the flat shield layer 11 and the like can be easily manufactured. On the other hand, as shown in the flat shield layers 11 and 21 (see FIGS. 1 and 2), the layer thickness continuously changes according to the distance from the center position P of the current density on the long side, or the flat shield layer. As shown in 31, 41, 61 (see FIGS. 3, 4, and 6), the layer thickness may change stepwise according to the distance from the center positions P, P _{1 to} P ₄ of the current density. preferable.

1,1a, 1b, 1c Flat cable 2,2a, 2b, 2c, 5a, 5b, 5c, 5d, 8a, 8b, 8c Conductor 3,3a, 3b, 3c, 6a, 6b, 6c, 6d, 9a, 9b , 9c Coating 4a, 4b, 4c, 4d Drain wire 7a, 7b, 7c Round wire cable 10, 20, 30, 40, 50, 60 Wire harness 11,21,31,41,51,61 Flat shield layer 11a, 21a Top 32, 42, 43, 62, 63 Convex

Claims (9)

A wire harness with a flat shield layer that contains a single or multiple cables.
In the flat shield layer, the layer thickness of the portion of the AC current density flowing through the cable that is close to the center position is larger than the layer thickness of the portion of the AC current density flowing through the cable that is far from the center position. A wire harness featuring. The flat shield layer has a long side and a short side at the circumference of a cross section along the width direction, and the layer thickness on the long side side is larger than the overall average layer thickness of the flat shield layer, and the short side The wire harness according to claim 1, wherein the layer thickness on the side is smaller than the average layer thickness. The wire harness according to claim 2, wherein the aspect ratio of the long side to the short side is 3 or more and 30 or less. A plurality of the cables are arranged in parallel in the width direction and included in the flat shield layer, and the layer thickness of the portion of the flat shield layer that covers between the plurality of cables is such that the plurality of flat shield layers have a thickness. The wire harness according to any one of claims 1 to 3, wherein the thickness is larger than the layer thickness other than the portion covering between the cables. Any one of claims 1 to 4, wherein the layer thickness of the portion having the largest layer thickness in the flat shield layer is twice or more and 10 times or less the layer thickness of the portion having the smallest layer thickness. The wire harness described in. A wire harness with a flat shield layer that contains a single or multiple cables.
The flat shield layer is characterized in that a drain wire shielded and grounded independently of the flat shield layer is provided on the outer surface of a portion of the flat shield layer that is close to the center position of the alternating current density flowing through the cable. Wire Harness. A plurality of the cables are arranged in parallel in the width direction and included in the flat shield layer, and the drain wire is provided on an outer surface of the flat shield layer so as to cover between the plurality of cables. The wire harness according to claim 6. 6. Claim 6 characterized in that the total of the layer thickness of the flat shield layer and the layer thickness of the drain wire is 2 times or more and 10 times or less the layer thickness of the portion having the smallest layer thickness of the flat shield layer. Or the wire harness according to 7. The wire harness according to any one of claims 1 to 8, wherein the thickness of the flat shield layer is 0.08 mm or more and 1 mm or less.

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