JP2019202671A - On-board wiring harness - Google Patents

Abstract

To provide an on-board wiring harness that can suppress noise.SOLUTION: An on-board wiring harness 1 includes: a plurality of pieces of wiring 2; a conductive shield body 3 for enclosing the plurality of pieces of wiring 2; and a plurality of ground connection members 4 connected between the conductive shield body 3 and a vehicle body B having ground potential, where a linear dimension L between the ground connection members 4 is set to be equal to or less than one-quarter of a wave length corresponding to the maximum frequency of noise.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an in-vehicle wire harness mounted on, for example, an automobile.

  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 end portions of the shield exterior material are connected to a ground point using a ground wire.

Japanese Patent Laying-Open No. 2015-72883

  By the way, since the both ends of the shield exterior material are earth | grounded, the wire harness described in patent document 1 has a fixed noise reduction effect. However, when external noise is coupled to the wire harness, a standing wave may be generated in the wire harness. For this reason, noise tends to increase at a specific frequency, and noise tends to be difficult to reduce. In addition, if the frequency at which noise increases is coincident with the frequency at which malfunctions are likely to occur in devices connected to the wire harness, malfunctions may occur in various devices connected to the wire harness.

  The present invention has been made in view of the above-described problems of the prior art, and an object of the present invention is to provide a vehicle-mounted wire harness that can suppress noise.

  In order to solve the above-described problems, the present invention provides a plurality of wirings, a conductive shield that surrounds the plurality of wirings, and a plurality connected between the conductive shield and a vehicle body having a ground potential. An in-vehicle wire harness including a plurality of ground connection members, wherein a length dimension between the plurality of ground connection members is set to a quarter or less of a wavelength corresponding to a maximum noise frequency. It is characterized by.

  Another invention is an in-vehicle wire harness provided with 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 set to a quarter or less of a wavelength corresponding to a maximum noise frequency.

  According to the present invention, noise can be suppressed.

1 is a longitudinal sectional view showing an in-vehicle wire harness according to a first embodiment of the present invention. It is the cross-sectional view which looked at the vehicle-mounted wire harness from the arrow II-II direction in FIG. It is a characteristic diagram which shows the frequency characteristic of insertion loss about 1st Embodiment and a 1st, 2nd comparative example. It is a longitudinal cross-sectional view which shows the vehicle-mounted wire harness by the 2nd Embodiment of this invention. It is a longitudinal cross-sectional view which expands and shows the ground connection member in FIG. It is a longitudinal cross-sectional view which shows the vehicle-mounted wire harness by the 3rd Embodiment of this invention. It is a longitudinal cross-sectional view which expands and shows the ground connection member in FIG. It is a longitudinal cross-sectional view which shows the vehicle-mounted wire harness by the 4th Embodiment of this invention. It is a longitudinal cross-sectional view which expands and shows the ground connection member in FIG. It is a longitudinal cross-sectional view which shows the vehicle-mounted wire harness by the 5th Embodiment of this invention. It is a longitudinal cross-sectional view which expands and shows the relay connector in FIG.

  Hereinafter, an in-vehicle wire harness according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

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

  In the wiring 2, a conductor wire is provided with an insulation coating, and transmits a signal or power, for example. 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 constituted by a conductive tube formed in a cylindrical shape with, for example, a conductive metal material. All the wirings 2 are accommodated inside the conductive shield 3. Thus, the conductive shield 3 electrically shields (shields) the wiring 2. Specific examples of the conductive shield 3 include a metal foil such as an aluminum foil, a braided wire knitted with a metal wire, and a resin film formed by vapor deposition or the like.

  The ground connection member 4 includes a conductive clamp 4A formed 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 can be elastically deformed. The conductive clamp 4A has a pair of end portions 4A1 and 4A2. These end portions 4A1 and 4A2 can be expanded. When the conductive shield 3 is inserted into the conductive clamp 4A, the distance between the end portions 4A1 and 4A2 is widened. At this time, the conductive clamp 4A is in contact with the conductive shield 3 with the conductive shield 3 sandwiched therebetween. The conductive clamp 4A is attached to the vehicle body B by, for example, a bolt (not shown).

  The length dimension L between the plurality of ground connection members 4 is set to ¼ or less of the wavelength corresponding to the highest noise frequency. Specifically, the length dimension L between two adjacent ground connection members 4 is set to 0.1875 m or less when the maximum noise frequency is 400 MHz.

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

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

  The dashed-dotted line in FIG. 3 has shown the insertion loss when not connecting the electroconductive shield 3 of the vehicle-mounted wire harness 1 to a ground (vehicle body B) as a 1st comparative example. The broken line in FIG. 3 shows the insertion loss when the conductive shield 3 is connected to the ground (vehicle body B) at both ends of the in-vehicle wire harness 1 as a second comparative example. The solid line in FIG. 3 shows the insertion loss when connecting all the ground connection members 4 at the 0.1875 m interval of the in-vehicle wire harness 1 to the ground (vehicle body B) as the first embodiment.

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

  In contrast, in the first embodiment, noise is suppressed by about 20 dB compared to the first comparative example in all frequency bands of 400 MHz or lower. In addition, in the first embodiment, the noise suppression effect is not significantly deteriorated at a specific frequency, and the noise suppression effect can be obtained in all frequency bands. For this reason, in 1st Embodiment, compared with the 2nd comparative example, the suppression effect of noise is high in the frequency band of 200 MHz or more and 300 MHz or less, for example.

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

  Further, even when noise is coupled to the in-vehicle wire harness 1, the noise does not increase at a specific frequency. More specifically, noise reflection occurs at a site where the impedance changes greatly, such as the ground connection member 4. 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. Electric power increases at the belly of standing waves. For this reason, when the space | interval (length dimension L) of the two adjacent ground connection members 4 becomes 1/4 of the wavelength of noise, for example, noise becomes large.

  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 smaller (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 about 0.1875 m. Therefore, in the present 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.

  Thereby, the antinode of a standing wave does not appear in the vehicle-mounted wire harness 1 at a frequency of 400 MHz or less. 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. For this reason, the increase in the noise by a standing wave can be suppressed. As a result, there is no frequency at which it is difficult to reduce noise, the noise suppression effect can be enhanced, and immunity resistance is enhanced.

  The plurality of ground connection members 4 include conductive clamps 4A. For this reason, the cylindrical conductive shield 3 can be sandwiched by the conductive clamp 4A, and the conductive shield 3 can be electrically connected to the vehicle body B using the conductive clamp 4A.

  Next, a second embodiment of the present invention will be described with reference to FIGS. A feature of the second embodiment is that the plurality of ground connection members include a relay connector including a line bypass capacitor connected between the plurality of wirings and the vehicle body. Note that in the second embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and 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 connection member 14 in substantially the same manner 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 in the same manner as 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 including a line bypass capacitor 16 connected between the plurality of wires 12 and the vehicle body B.

  The relay connector 15 is located between the two divided wires 12A and electrically connects between them. In addition to this, the relay connector 15 is located between the two divided 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 for connecting the two divided wirings 12A, and a second conductive pattern provided on the printed circuit board 15A for connecting the two divided shielding bodies 13A. A conductor pattern 15C and a connection portion 15D that electrically connects the second conductor pattern 15C and the divided shield 13A to the vehicle body B are provided. The line bypass capacitor 16 is constituted by, 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 wirings 12 are formed on the printed board 15A. For this reason, the same number of line bypass capacitors 16 as the number of wirings 12 are provided on the printed board 15A.

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

  Thus, also in the second embodiment configured as described above, it is possible to obtain substantially the same operational effects as those of the first embodiment described above. In the second embodiment, the plurality of ground connection members 14 include relay connectors 15 each having a line bypass capacitor 16 connected between the plurality of wires 12 and the vehicle body B. Therefore, noise coupled to the wiring 12 can be released to the vehicle body B through the line bypass capacitor 16. Therefore, the immunity tolerance of the vehicle-mounted wire harness 11 can be improved compared to the first embodiment.

  Next, a third embodiment of the present invention will be described with reference to FIGS. The feature of the third embodiment resides in that the line bypass capacitor is constituted by a feedthrough capacitor. Note that in the third embodiment, the same components as those of the second embodiment are denoted by the same reference numerals, and description thereof is omitted.

  The in-vehicle wire harness 21 according to the third embodiment includes the wiring 12, the conductive shield 13, and the ground connection member 22 in substantially the same manner 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 including a feedthrough capacitor 24 as a line bypass capacitor connected between the plurality of wirings 12 and the vehicle body B. The feedthrough capacitor 24 includes a signal line portion 24A penetrating in the axial direction and a cylindrical outer peripheral electrode portion 24B surrounding the signal line portion 24A while being insulated from the signal line portion 24A. For example, an insulating resin material is filled between the signal line portion 24A and the outer peripheral electrode portion 24B. Both ends of the signal line portion 24A are connected to the two divided wirings 12A.

  The relay connector 23 holds a plurality of feedthrough capacitors 24. For this reason, the relay connector 23 is located between the two divided wirings 12 </ b> A and electrically connects the two divided wirings 12 </ b> A via the feedthrough capacitor 24. The relay connector 23 is provided on both ends of the feedthrough capacitor 24 and includes a connection portion 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 connection portion 23A. As many feedthrough capacitors 24 as relay wires 23 are provided as the number of wires 12.

  The length dimension L between the plurality of ground connection members 22 is set to ¼ or less of the wavelength according to the highest noise frequency. Specifically, the length dimension L between two adjacent ground connection members 22 is set to 0.1875 m or less when the maximum noise frequency is 400 MHz.

  Thus, also in the third embodiment configured as described above, it is possible to obtain substantially the same operational effects as those of the second embodiment described above. The feedthrough capacitor 24 is not limited to a cylindrical shape, and may be a three-terminal capacitor formed in a chip shape, for example.

  Next, a fourth embodiment of the present invention will be described with reference to FIGS. The feature of the fourth embodiment includes a relay connector in which the plurality of ground connection members include a line bypass capacitor connected between the plurality of wirings and the vehicle body, and a resistor connected in series to the line bypass capacitor. There is. Note that, in the fourth embodiment, the same components as those of the second embodiment are denoted by the same reference numerals, and description thereof is omitted.

  The in-vehicle wire harness 31 according to the fourth embodiment includes the wiring 12, the conductive shield 13, and the ground connection member 32 in substantially the same manner as the in-vehicle 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 wires 12 and the vehicle body B, and a resistor 35 connected in series to the line bypass capacitor 34. A relay connector 33 is included.

  The relay connector 33 is located between the two divided wirings 12A and electrically connects between them. In addition, the relay connector 33 is located between the two divided shields 13A and electrically connects between them. The relay connector 33 is configured in substantially the same manner as the relay connector 15 according to the second embodiment. Therefore, the relay connector 33 connects the printed board 33A, the first conductor pattern 33B provided on the printed board 33A to connect the two divided wirings 12A, and the two divided shields 13A provided on the printed board 33A. A second conductor pattern 33C and a connection portion 33D that electrically connects 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 are connected between the first conductor pattern 33B and the second conductor pattern 33C. Both the line bypass capacitor 34 and the resistor 35 are constituted by chip parts.

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

  The length dimension L between the plurality of ground connection members 32 is set to a quarter or less 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 0.1875 m or less when the maximum noise frequency is 400 MHz.

  Thus, also in the fourth embodiment configured as described above, it is possible to obtain substantially the same operational effects as those of the second embodiment described above. When the resistance value between the divided shield 13A and the vehicle body B is large to some extent, the high frequency noise coupled to the divided shield 13A does not escape to the vehicle body B and is coupled to the wiring 12 via the line bypass capacitor 34. There is a risk of it. In contrast, in the fourth embodiment, the plurality of ground connection members 32 include a line bypass capacitor 34 connected between the plurality of wires 12 and the vehicle body B, and a resistor 35 connected in series to the line bypass capacitor 34. The relay connector 33 provided with these is included. For this reason, it is possible to suppress the high-frequency noise coupled from the divided shield 13A to the wiring 12 by the resistor 35, and the high-frequency noise coupled to the divided shield 13A can be released to the vehicle body B. Accordingly, 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. A feature of the fifth embodiment is that a plurality of wirings are surrounded by an insulator, and a relay connector having a line bypass capacitor connected between the plurality of wirings and the vehicle body is provided. Note that, in the fifth embodiment, the same components as those of the second embodiment are denoted by the same reference numerals, and description thereof is omitted.

  A vehicle-mounted wire harness 41 according to the fifth embodiment includes a 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 constituted by a resin tube formed in a cylindrical shape by an insulating resin material, for example. All the wirings 42 are accommodated inside the insulator 43. The insulator 43 is divided into a plurality of divided insulators 43A.

  The relay connector 44 includes a line bypass capacitor 16 connected between the plurality of wirings 42 and the vehicle body B. The relay connector 44 is located between the two divided wirings 42A and electrically connects between them. In addition, the relay connector 44 is located between the two divided insulators 43A. The relay connector 44 includes a printed circuit board 44A, a first conductor pattern 44B that is provided on the printed circuit board 44A and connects the two divided wirings 42A, a second conductor pattern 44C that is separate from the first conductor pattern 44B, A connecting 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 wirings 42 are formed on the printed circuit board 44A. For this reason, the same number of line bypass capacitors 16 as the number of wirings 42 are provided on the printed circuit board 44A.

  The length dimension L between the plurality of relay connectors 44 is set to ¼ or less of the wavelength according to the highest noise frequency. Specifically, the length dimension L between two adjacent relay connectors 44 is set to 0.1875 m or less when the maximum noise frequency is 400 MHz.

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

  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. 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 a feedthrough capacitor may be used instead of the line bypass capacitor 16 as in the third embodiment.

  The specific numerical values described in the above embodiments are examples, and are not limited to the exemplified values. These numerical values are appropriately set according to, for example, the specification to be applied.

  Each of the embodiments described above is an exemplification, and needless to say, partial replacement or combination of configurations shown in different embodiments is possible.

  Next, the invention included in the above embodiment will be described. The present invention includes a plurality of wirings, a conductive shield surrounding the plurality of wirings, and a plurality of ground connection members connected between the conductive shield and a vehicle body having a ground potential. The wire harness for in-vehicle use is characterized in that a length dimension between the plurality of ground connection members is set to a quarter or less of a wavelength corresponding to the highest frequency of noise.

  With this configuration, even when a standing wave is generated between the ground connection members, the frequency of the standing wave is higher than the highest noise frequency. For this reason, the increase in the noise by a standing wave can be suppressed. As a result, there is no frequency at which it is difficult to reduce noise, and the noise suppression effect can be enhanced.

  In the present invention, the plurality of ground connection members include conductive clamps. For this reason, the cylindrical conductive shield can be sandwiched by the conductive clamp, and the conductive shield can be electrically connected to the vehicle body using the conductive clamp.

  In the present invention, the plurality of ground connection members include a relay connector provided with a line bypass capacitor connected between the plurality of wirings and the vehicle body. For this reason, noise coupled to the wiring can be released to the vehicle body through the line bypass capacitor. Accordingly, the immunity resistance of the in-vehicle wire harness can be improved.

  In the present invention, the plurality of ground connection members include a relay connector including a line bypass capacitor connected between the plurality of wirings and the vehicle body, and a resistor connected in series to the line bypass capacitor. Yes. For this reason, it can suppress by a resistance that high frequency noise couple | bonds with a wiring from a conductive shield, and the high frequency noise couple | bonded with the conductive shield can be escaped to a vehicle body. Accordingly, the immunity resistance of the in-vehicle wire harness can be further improved.

  In the present invention, the length dimension between the plurality of ground connection members is set to 0.1875 m or less when the highest noise frequency is 400 MHz. Thereby, even when a standing wave is generated between the ground connection members, the frequency of the standing wave is higher than 400 MHz which is the highest noise frequency. For this reason, the increase in the noise by a standing wave can be suppressed. As a result, there is no frequency at which it is difficult to reduce noise, and the noise suppression effect can be enhanced.

  Further, the present invention is a vehicle-mounted wire harness provided with 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, The length dimension between the plurality of relay connectors is characterized by being set to a quarter or less of the wavelength corresponding to the highest frequency of noise. For this reason, noise coupled to the wiring can be released to the vehicle body through the line bypass capacitor. Accordingly, the immunity resistance of the in-vehicle wire harness can be improved.

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 Resistance 43 Insulator

Claims (6)

Multiple wires,
A conductive shield surrounding the plurality of wirings;
A vehicle-mounted wire harness comprising a plurality of ground connection members connected between the conductive shield and a vehicle body having a ground potential;
A length dimension between the plurality of ground connection members is set to a quarter or less of a wavelength corresponding to the highest frequency of noise.   The in-vehicle wire harness according to claim 1, wherein the plurality of ground connection members include conductive clamps.   The in-vehicle wire harness according to claim 1, wherein the plurality of ground connection members include a relay connector including a line bypass capacitor connected between the plurality of wirings and the vehicle body.   The plurality of ground connection members include a relay connector including a line bypass capacitor connected between the plurality of wirings and the vehicle body, and a resistor connected in series to the line bypass capacitor. The in-vehicle wire harness according to claim 1 or 2.   5. The length dimension between the plurality of ground connection members is set to 0.1875 m or less when a maximum frequency of the noise is 400 MHz. 6. Automotive wire harness. An in-vehicle wire harness having a plurality of wires,
A plurality of relay connectors having line bypass capacitors connected between the plurality of wires and a vehicle body having a ground potential;
A length dimension between the plurality of relay connectors is set to a quarter or less of a wavelength corresponding to a maximum frequency of noise.

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