JP7205078B2 - automotive wiring harness - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an in-vehicle wire harness mounted in an automobile, for example.

Patent Literature 1 discloses a wire harness including a plurality of wirings and a shield exterior material surrounding the plurality of wirings. At this time, both ends of the shield sheathing material are connected to ground points using ground wires.

JP 2015-72883 A

By the way, in the wire harness described in Patent Document 1, both ends of the shield outer material are grounded, so that a certain noise reduction effect can be obtained. However, standing waves may occur in the wire harness when external noise is coupled to the wire harness. Therefore, noise tends to increase at a specific frequency, making it difficult to reduce noise. Further, if the frequency at which the noise increases coincides with the frequency at which the devices connected to the wire harness are likely to malfunction, various devices connected to the wire harness may malfunction.

SUMMARY OF THE INVENTION An object of the present invention is to provide a vehicle-mounted wire harness capable of suppressing noise.

In order to solve the above-described problems, the present invention provides a plurality of wires, a conductive shield surrounding the plurality of wires, and a plurality of wires connected between the conductive shield and a vehicle body having a ground potential. and a ground connection member, wherein the plurality of ground connection members are arranged at intervals in the length direction of the wiring, and the length dimension between the plurality of ground connection members is set to less than a quarter of the wavelength corresponding to the highest frequency of noise, and is characterized by suppressing the generation of standing waves in a band below the highest frequency of noise .

According to the present invention, noise can be suppressed.

1 is a vertical cross-sectional view showing a vehicle-mounted wire harness according to a first embodiment of the present invention; FIG. FIG. 2 is a cross-sectional view of the in-vehicle wire harness as viewed in the direction of arrows II-II in FIG. 1; FIG. 5 is a characteristic diagram showing frequency characteristics of insertion loss in the first embodiment and first and second comparative examples; FIG. 2 is a longitudinal sectional view showing a vehicle-mounted wiring harness according to a second embodiment of the present invention; FIG. 5 is a longitudinal sectional view showing an enlarged ground connection member in FIG. 4; FIG. 10 is a vertical cross-sectional view showing a vehicle-mounted wire harness according to a third embodiment of the present invention; FIG. 7 is a longitudinal sectional view showing an enlarged ground connection member in FIG. 6; FIG. 11 is a vertical cross-sectional view showing a vehicle-mounted wire harness according to a fourth embodiment of the present invention; FIG. 9 is a longitudinal sectional view showing an enlarged ground connection member in FIG. 8; FIG. 11 is a vertical cross-sectional view showing a vehicle-mounted wiring harness according to a fifth embodiment of the present invention; FIG. 11 is a longitudinal sectional view showing an enlarged relay connector in FIG. 10;

The present invention belongs to a group of inventions including a plurality of inventions described below. Hereinafter, as embodiments of the invention group, first to fifth embodiments will be described. The first to fourth embodiments correspond to the invention described in the claims of the present applicant.
DETAILED DESCRIPTION OF THE INVENTION A vehicle-mounted wire harness according to an embodiment of the present invention will be described in detail below with reference to the accompanying drawings.

1 and 2 show an in-vehicle wiring harness 1 according to a first embodiment of the present invention. A vehicle wiring harness 1 includes a plurality of wirings 2, a conductive shield 3 surrounding the plurality of wirings 2, and a plurality of ground connections connected between the conductive shield 3 and a vehicle body B having a ground potential. a member 4;

The wiring 2 is a conductor wire coated with an insulating coating, and transmits, for example, a signal or electric power. Both ends of the wiring 2 are connected to various devices such as a battery, an inverter, a motor, a controller, and the like.

The conductive shield 3 is composed of, for example, a cylindrical conductive tube made of a conductive metal material. All the wires 2 are accommodated inside the conductive shield 3 . Thereby, the conductive shield 3 electrically shields the wiring 2 . Specific examples of the conductive shield 3 include a metal foil such as aluminum foil, a braided wire in which metal wires are woven, and a metal film formed on a resin film by vapor deposition or the like.

The ground connection member 4 includes a conductive clamp 4A made of, for example, a conductive metal material. The conductive clamp 4A is formed in a C shape extending along the circumferential direction of the conductive shield 3 and is elastically deformable. Conductive clamp 4A has a pair of ends 4A1 and 4A2. These ends 4A1 and 4A2 can be expanded. When the conductive shield 3 is inserted inside the conductive clamp 4A, the distance between the ends 4A1 and 4A2 is widened. At this time, the conductive clamp 4A is in contact with the conductive shield 3 while holding the conductive shield 3 therebetween. The conductive clamp 4A is attached to the vehicle body B by, for example, bolts (not shown).

A length dimension L between the plurality of ground connection members 4 is set to less than a quarter of the wavelength corresponding to the highest frequency of noise. Specifically, the length dimension L between two adjacent ground connection members 4 is set to less than 0.1875 m when the maximum noise frequency is 400 MHz.

The in-vehicle wire harness 1 of this embodiment is configured as described above. Next, in order to confirm the noise suppression effect of the in-vehicle wire harness 1, a test simulating BCI (Bulk Current Injection) was performed on the in-vehicle wire harness 1. FIG. The results are shown in FIG.

In the BCI test, noise is injected into the in-vehicle wiring harness 1 using an injection probe. FIG. 3 shows the frequency characteristics of the insertion loss (S21) between port 1 (input terminal) as an injection probe and port 2 (output terminal) as an in-vehicle device end of the in-vehicle wiring harness 1. .

The dashed-dotted line in FIG. 3 indicates the insertion loss when the conductive shield 3 of the in-vehicle wiring harness 1 is not connected to the ground (vehicle body B) as a first comparative example. The dashed line in FIG. 3 indicates the insertion loss when the conductive shields 3 are connected to the ground (vehicle body B) at both ends of the vehicle-mounted wire harness 1 as a second comparative example. The solid line in FIG. 3 indicates the insertion loss when all the ground connection members 4 of the vehicle-mounted wire harness 1 with an interval of 0.1875 m are connected to the ground (vehicle body B) as the first embodiment.

As shown in FIG. 3, noise is suppressed in the second comparative example compared to the first comparative example. However, even in the second comparative example, the noise suppression effect is small in, for example, a frequency band of 200 MHz or more and 300 MHz or less.

In contrast, in the first embodiment, noise is suppressed by about 20 dB in all frequency bands below 400 MHz compared to the first comparative example. In addition to this, in the first embodiment, the noise suppression effect does not significantly deteriorate at a specific frequency, and the noise suppression effect can be obtained in all frequency bands. Therefore, in the first embodiment, compared to the second comparative example, for example, the noise suppression effect is higher in the frequency band of 200 MHz or more and 300 MHz or less.

Thus, in the in-vehicle wire harness 1 according to this embodiment, three or more ground connection members 4 are connected to the vehicle body B having the ground potential. For this reason, noise can be released to the vehicle body B side through the plurality of ground connection members 4 , so external noise is less likely to be coupled to the in-vehicle wire harness 1 .

Moreover, even when noise is coupled to the in-vehicle wiring harness 1, the noise does not increase at a specific frequency. More specifically, noise reflection occurs in a portion such as the ground connection member 4 where the impedance changes greatly. When a standing wave is generated in the in-vehicle wire harness 1 , the first antinode of the standing wave arrives at a position that is a quarter of the wavelength from the end of the in-vehicle wire harness 1 . The electric power becomes strong at the antinode of the standing wave. Therefore, when the interval (length dimension L) between two adjacent ground connection members 4 is, for example, a quarter of the wavelength of noise, noise increases.

On the other hand, in the in-vehicle wire harness 1 according to the present embodiment, the length dimension L between the plurality of ground connection members 4 is set to a value smaller than (less than) a quarter of the wavelength corresponding to the highest noise frequency. is set. At this time, a quarter of the wavelength corresponding to 400 MHz noise is approximately 0.1875 m. Therefore, in this embodiment, the length dimension L between the plurality of ground connection members 4 is set to 0.1875 m or less when the maximum noise frequency is 400 MHz.

As a result, at a frequency of 400 MHz or less, an antinode of the standing wave does not appear in the in-vehicle wiring harness 1 . That is, even when a standing wave is generated between the ground connection members 4, the frequency of the standing wave is higher than 400 MHz, which is the highest noise frequency. Therefore, an increase in noise due to standing waves can be suppressed. As a result, there are no frequencies at which noise is difficult to reduce, so that the noise suppression effect can be enhanced and the immunity resistance can be enhanced.

Also, the plurality of ground connection members 4 includes conductive clamps 4A. Therefore, the cylindrical conductive shield 3 can be sandwiched between the conductive clamps 4A, and the conductive shield 3 can be electrically connected to the vehicle body B using the conductive clamps 4A.

Next, a second embodiment of the present invention will be described with reference to FIGS. 4 and 5. FIG. A feature of the second embodiment is that the plurality of ground connection members includes relay connectors having line bypass capacitors connected between the plurality of wirings and the vehicle body. In addition, in the second embodiment, the same components as those in the first embodiment are given the same reference numerals, and the description thereof is omitted.

The in-vehicle wire harness 11 according to the second embodiment includes a wiring 12, a conductive shield 13, and a ground connecting member 14, substantially the same as the in-vehicle wire harness 1 according to the first embodiment. The wiring 12 is configured similarly to the wiring 2 of the first embodiment. The conductive shield 13 is configured similarly to the conductive shield 3 of the first embodiment. However, the wiring 12 is divided into a plurality of divided wirings 12A. Similarly, the conductive shield 13 is divided into a plurality of divided shields 13A.

In the second embodiment, the ground connection member 14 includes a relay connector 15 having a line bypass capacitor 16 connected between the plurality of wirings 12 and the vehicle body B. As shown in FIG.

The relay connector 15 is positioned between the two split wirings 12A and electrically connects them. In addition, the relay connector 15 is located between the two split shields 13A and electrically connects them. The relay connector 15 includes a printed circuit board 15A, a first conductor pattern 15B provided on the printed circuit board 15A and connecting two divided wirings 12A, and a second conductive pattern 15B provided on the printed circuit board 15A and connecting two divided shields 13A. A conductor pattern 15C and a connection portion 15D for electrically connecting the second conductor pattern 15C and the divided shield 13A to the vehicle body B are provided. The line bypass capacitor 16 is composed of, for example, a chip component, and is electrically connected between the first conductor pattern 15B and the second conductor pattern 15C.

At this time, the same number of first conductor patterns 15B as the number of wires 12 are formed on the printed circuit board 15A. For this reason, the printed circuit board 15A is provided with the same number of line bypass capacitors 16 as the number of the wirings 12 .

A length dimension L between the plurality of ground connection members 14 is set to less than a quarter of the wavelength corresponding to the highest frequency of noise. Specifically, the length dimension L between two adjacent ground connection members 14 is set to less than 0.1875 m when the maximum noise frequency is 400 MHz.

Thus, substantially the same effects as those of the first embodiment described above can be obtained in the second embodiment configured as described above. Further, in the second embodiment, the plurality of ground connection members 14 includes relay connectors 15 having line bypass capacitors 16 connected between the plurality of wirings 12 and the vehicle body B. As shown in FIG. Therefore, noise coupled to the wiring 12 can be released to the vehicle body B through the line bypass capacitor 16. - 特許庁Therefore, compared with the first embodiment, it is possible to improve the immunity resistance of the in-vehicle wire harness 11 .

Next, a third embodiment of the present invention will be described with reference to FIGS. 6 and 7. FIG. A feature of the third embodiment resides in that the line bypass capacitor is constituted by a feedthrough capacitor. In addition, in 3rd Embodiment, the same code|symbol is attached|subjected to the component same as 2nd Embodiment, and the description is abbreviate|omitted.

The in-vehicle wire harness 21 according to the third embodiment includes a wiring 12, a conductive shield 13, and a ground connection member 22, substantially the same as the in-vehicle wire harness 11 according to the second embodiment.

In the third embodiment, the ground connection member 22 includes a relay connector 23 having a feedthrough capacitor 24 as a line bypass capacitor connected between the plurality of wirings 12 and the vehicle body B. FIG. The feedthrough capacitor 24 includes a signal line portion 24A penetrating in the axial direction, and a cylindrical outer electrode portion 24B surrounding the signal line portion 24A while being insulated from the signal line portion 24A. An insulating resin material, for example, is filled between the signal line portion 24A and the peripheral electrode portion 24B. Both ends of the signal line portion 24A are connected to the two split wirings 12A.

The relay connector 23 holds a plurality of feedthrough capacitors 24 . Therefore, the relay connector 23 is positioned between the two divided wirings 12A and electrically connects the two divided wirings 12A via the feedthrough capacitors 24 . The relay connector 23 is provided on both end sides of the feedthrough capacitor 24 and has connection portions 23A. At this time, the outer peripheral electrode portion 24B of the feedthrough capacitor 24 is electrically connected to the vehicle body B through the connecting portion 23A. The feedthrough capacitors 24 are provided in the relay connector 23 in the same number as the wirings 12 .

A length dimension L between the plurality of ground connection members 22 is set to less than a quarter of the wavelength corresponding to the highest frequency of noise. Specifically, the length dimension L between two adjacent ground connection members 22 is set to less than 0.1875 m when the maximum noise frequency is 400 MHz.

Thus, even in the third embodiment configured in this way, substantially the same effects as those of the second embodiment can be obtained. The feedthrough capacitor 24 is not limited to a columnar capacitor, and may be, for example, a chip-shaped three-terminal capacitor.

Next, a fourth embodiment of the present invention will be described with reference to FIGS. 8 and 9. FIG. A feature of the fourth embodiment is that the plurality of ground connection members includes a relay connector including a line bypass capacitor connected between a plurality of wirings and the vehicle body, and a resistor connected in series with the line bypass capacitor. That's what it is. In addition, in 4th Embodiment, the same code|symbol is attached|subjected to the component same as 2nd Embodiment, and the description is abbreviate|omitted.

A vehicle-mounted wire harness 31 according to the fourth embodiment includes a wiring 12, a conductive shield 13, and a ground connection member 32, substantially the same as the vehicle-mounted wire harness 11 according to the second embodiment.

However, in the fourth embodiment, the ground connection member 32 includes a line bypass capacitor 34 connected between the plurality of wirings 12 and the vehicle body B, and a resistor 35 connected in series with the line bypass capacitor 34. A relay connector 33 is included.

The relay connector 33 is positioned between the two split wirings 12A and electrically connects them. In addition, the relay connector 33 is located between the two split shields 13A and electrically connects them. The relay connector 33 has substantially the same configuration as the relay connector 15 according to the second embodiment. Therefore, the relay connector 33 connects the printed circuit board 33A, the first conductor pattern 33B provided on the printed circuit board 33A and connecting the two divided wirings 12A, and the two divided shields 13A provided on the printed circuit board 33A. A second conductor pattern 33C and a connection portion 33D for electrically connecting the second conductor pattern 33C and the divided shield 13A to the vehicle body B are provided. The line bypass capacitor 34 and the resistor 35 are connected in series and connected between the first conductor pattern 33B and the second conductor pattern 33C. Both the line bypass capacitor 34 and the resistor 35 are composed of chip parts.

At this time, the same number of first conductor patterns 33B as the number of wires 12 are formed on the printed circuit board 33A. For this reason, the printed circuit board 33A is provided with the same number of line bypass capacitors 34 and resistors 35 as the number of wires 12 .

A length dimension L between the plurality of ground connection members 32 is set to less than a quarter of the wavelength corresponding to the highest frequency of noise. Specifically, the length dimension L between two adjacent ground connection members 32 is set to less than 0.1875 m when the maximum noise frequency is 400 MHz.

Thus, even in the fourth embodiment configured in this manner, substantially the same effects as those of the second embodiment can be obtained. Further, when the resistance value between the divided shield 13A and the vehicle body B is relatively large, the high frequency noise coupled to the divided shield 13A is coupled to the wiring 12 via the line bypass capacitor 34 without escaping to the vehicle body B. There is a risk of it happening. On the other hand, in the fourth embodiment, the plurality of ground connection members 32 include line bypass capacitors 34 connected between the plurality of wirings 12 and the vehicle body B, and resistors 35 connected in series to the line bypass capacitors 34 . and a relay connector 33 provided with. Therefore, the resistor 35 can suppress high-frequency noise from being coupled to the wiring 12 from the divided shield 13A, and the high-frequency noise coupled to the divided shield 13A can escape to the vehicle body B. Therefore, the immunity resistance of the in-vehicle wire harness 31 can be further improved.

Next, a fifth embodiment of the present invention will be described with reference to FIGS. 10 and 11. FIG. A feature of the fifth embodiment is that a plurality of wires are surrounded by an insulator, and a relay connector having a line bypass capacitor connected between the plurality of wires and the vehicle body is provided. In addition, in the fifth embodiment, the same components as those in the second embodiment are given the same reference numerals, and the description thereof is omitted.

A vehicle-mounted wiring harness 41 according to the fifth embodiment includes wiring 42 , an insulator 43 , and a relay connector 44 . The wiring 42 is configured similarly to the wiring 12 of the second embodiment. The wiring 42 is divided into a plurality of divided wirings 42A.

The insulator 43 is composed of, for example, a cylindrical resin tube made of an insulating resin material. All the wirings 42 are housed inside the insulator 43 . The insulator 43 is split into a plurality of split insulators 43A.

The relay connector 44 has a line bypass capacitor 16 connected between the plurality of wirings 42 and the vehicle body B. As shown in FIG. The relay connector 44 is located between the two split wirings 42A and electrically connects them. In addition, the relay connector 44 is positioned between the two split insulators 43A. The relay connector 44 includes a printed circuit board 44A, a first conductor pattern 44B provided on the printed circuit board 44A and connecting the two split wirings 42A, a second conductor pattern 44C separate from the first conductor pattern 44B, A connection portion 44D for electrically connecting the second conductor pattern 44C to the vehicle body B is provided. The line bypass capacitor 16 is connected between the first conductor pattern 44B and the second conductor pattern 44C.

At this time, the same number of first conductor patterns 44B as the number of wires 42 are formed on the printed circuit board 44A. For this reason, the printed circuit board 44A is provided with the same number of line bypass capacitors 16 as the number of the wirings 42 .

A length dimension L between the plurality of relay connectors 44 is set to less than a quarter of the wavelength corresponding to the highest frequency of noise. Specifically, the length dimension L between two adjacent relay connectors 44 is set to less than 0.1875 m when the maximum noise frequency is 400 MHz.

Thus, in the fifth embodiment configured as described above, although noise is coupled to the in-vehicle wire harness 41 , the noise can escape to the vehicle body B via the line bypass capacitor 16 . In addition, at a frequency of 400 MHz or less, the antinode of the standing wave does not appear in the in-vehicle wiring harness 41 .

In addition, in the fifth embodiment, the wiring 42 is connected to the vehicle body B via the line bypass capacitor 16 . The present invention is not limited to this. For example, as in the fourth embodiment, the wiring may be connected to the vehicle body via a series connection circuit of a line bypass capacitor and a resistor. Also, in the fifth embodiment, the line bypass capacitor 16 made of a chip component is used. The present invention is not limited to this, and instead of the line bypass capacitor 16, a feedthrough capacitor may be used as in the third embodiment.

The specific numerical values described in each of the above embodiments are examples, and are not limited to the illustrated values. These numerical values are appropriately set, for example, according to the specifications of the application target.

It is needless to say that each of the above embodiments is an example, and partial substitutions or combinations of configurations shown in different embodiments are possible.

Next, the inventions included in the above embodiments will be described. The present invention includes a plurality of wires, a conductive shield surrounding the plurality of wires, and a plurality of ground connection members connected between the conductive shield and a vehicle body having a ground potential. The wiring harness for in-vehicle use is characterized in that the length dimension between the plurality of ground connection members is set to be less than 1/4 of the wavelength corresponding to the highest frequency of noise.

With this configuration, even when a standing wave occurs between the ground connection members, the frequency of the standing wave is higher than the maximum noise frequency. Therefore, an increase in noise due to standing waves can be suppressed. As a result, there are no frequencies at which noise is difficult to reduce, and the noise suppression effect can be enhanced.

In the present invention, the plurality of ground connection members includes conductive clamps. Therefore, the cylindrical conductive shield can be sandwiched between the conductive clamps, and the conductive clamp can be used to electrically connect the conductive shield to the vehicle body.

In the present invention, the plurality of ground connection members include relay connectors having line bypass capacitors connected between the plurality of wirings and the vehicle body. Therefore, noise coupled to the wiring can be released to the vehicle body through the line bypass capacitor. Therefore, it is possible to improve the immunity resistance of the in-vehicle wire harness.

In the present invention, the plurality of ground connection members include a relay connector having a line bypass capacitor connected between the plurality of wirings and the vehicle body, and a resistor connected in series with the line bypass capacitor. there is Therefore, the resistance can prevent high-frequency noise from being coupled to the wiring from the conductive shield, allowing the high-frequency noise coupled to the conductive shield to escape to the vehicle body. Therefore, it is possible to further improve the immunity resistance of the in-vehicle wire harness.

In the present invention, the length dimension between the plurality of ground connection members is set to less than 0.1875 m when the maximum frequency of the noise is 400 MHz. As a result, even when a standing wave occurs between the ground connection members, the frequency of the standing wave is higher than the maximum noise frequency of 400 MHz. Therefore, an increase in noise due to standing waves can be suppressed. As a result, there are no frequencies at which noise is difficult to reduce, and the noise suppression effect can be enhanced.

Further, the present invention provides an in-vehicle wiring harness having a plurality of wirings, comprising a plurality of relay connectors having line bypass capacitors connected between the plurality of wirings and a vehicle body having a ground potential, A length dimension between the plurality of relay connectors is characterized in that it is set to less than a quarter of the wavelength corresponding to the highest frequency of noise. Therefore, noise coupled to the wiring can be released to the vehicle body through the line bypass capacitor. Therefore, it is possible to improve the immunity resistance of the in-vehicle wire harness.

Reference Signs List 1, 11, 21, 31, 41 in-vehicle wire harness 2, 12, 42 wiring 3, 13 conductive shield 4, 14, 22, 32 ground connection member 4A conductive clamp 15, 23, 33, 44 relay connector 16 , 34 line bypass capacitor 24 feedthrough capacitor (line bypass capacitor)
35 resistor 43 insulator

Claims (5)

multiple wires and
a conductive shield surrounding the plurality of wires;
An in-vehicle wire harness comprising a plurality of ground connection members connected between the conductive shield and a vehicle body having a ground potential,
The plurality of ground connection members are arranged at intervals in the length direction of the wiring,
The length dimension between the plurality of ground connection members is set to be less than a quarter of the wavelength corresponding to the maximum frequency of noise, thereby suppressing the generation of standing waves in a band below the maximum frequency of noise . An in-vehicle wire harness characterized by: 2. The vehicle-mounted wiring harness according to claim 1, wherein the plurality of ground connection members include conductive clamps. 3. The in-vehicle wire harness according to claim 1, wherein the plurality of ground connection members include a relay connector having a line bypass capacitor connected between the plurality of wires and the vehicle body. The plurality of ground connection members include a relay connector having a line bypass capacitor connected between the plurality of wires and the vehicle body, and a resistor connected in series with the line bypass capacitor. The vehicle-mounted wire harness according to claim 1 or 2. 5. The length dimension between the plurality of ground connection members is set to less than 0.1875 m when the maximum frequency of the noise is 400 MHz. Automotive wiring harness.

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