JP2016225104A - Shielded conductive path - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a sufficient noise canceling effect in both high-frequency and low-frequency bands.SOLUTION: A shielded conductive path A includes a conductive path body 10, a parallel shield line 14 arranged to be parallel to the conductive path body 10, and a spiral shield line 17 spirally wired along an outer circumference of the conductive path body 10 and in contact with the parallel shield line 14 in a crossing state. The parallel shield line 14 exhibits a good noise canceling effect in a low-frequency band. Since a noise current in the spiral shield line 17 easily flows toward the earth through the parallel shield line 14, the spiral shield line 17 exhibits a good noise canceling effect in a high-frequency band.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a shield conductive path.

  Patent Document 1 discloses a shielded cable having a structure in which a wire bundle is covered with a first strip member and a second strip member having a metal layer, and a drain wire is sandwiched between the first strip member and the second strip member. Yes. The metal layers and drain wires of the first and second belt-like members exhibit a shielding function with respect to the wire bundle.

Japanese Patent No. 5682597

  In the shielded cable, the metal layers of the first and second belt-like members are spirally wound along the outer periphery of the electric wire bundle, and the drain wire is also spirally wound along the outer periphery of the electric wire. However, the shielding means in which the metal layer and the drain wire are spirally wound cannot be expected to have a noise canceling effect in the low frequency band. Also, the noise cancellation effect in the high frequency band is not sufficient.

  The present invention has been completed based on the above-described circumstances, and an object thereof is to obtain a sufficient noise canceling effect in both high and low frequency bands.

The shield conductive path of the present invention is
A conductive path body;
A parallel shield wire arranged in parallel with the conductive path body;
A spiral shield wire is provided along the outer periphery of the conductive path main body and spirally connected to the parallel shield wire in a crossed state.

  The parallel shield wire exhibits a good noise canceling effect in the low frequency band. Further, since the noise current of the spiral shielded wire easily flows to the ground side through the parallel shielded wire, the spiral shielded wire exhibits a good noise canceling effect in the high frequency band.

Partially cutaway side view of shield conductive path of Example 1 XX sectional view of FIG. Partially cutaway side view of shield conductive path of Example 2

(A) The shield conductive path of the present invention may include a cylindrical fastening member that presses the spiral shield wire and the parallel shield wire toward the outer peripheral side of the conductive path main body.
According to this configuration, the spiral shield wire and the parallel shield wire can be reliably brought into contact with each other by the pressing action of the fastening member.

(B) In the shield conductive path of the present invention, the parallel shield line may be routed along a path that alternately crosses the spiral inside and outside of the spiral shield line.
According to this configuration, the spiral shield wire and the parallel shield wire can be prevented from being displaced away from the conductive path main body in the radial direction.

(C) The shield conductive path of the present invention is shaped in (b) so that the parallel shield wire is curved so as to form a waveform, and the spiral shield wire is formed at the crest and trough of the wave. It may be in contact with the parallel shield wire.
According to this configuration, since the spiral shield wire is positioned by fitting into the crest and trough portions of the parallel shield wire, the spiral pitch of the spiral shield wire is stabilized.

(D) In the shield conductive path of the present invention, a small-diameter portion that is partially thinned may be formed in a contact portion of the parallel shield wire with the spiral shield wire.
According to this configuration, since the spiral shield wire is positioned by fitting into the small diameter portion, the spiral pitch of the spiral shield wire is stabilized.

<Example 1>
Embodiment 1 of the present invention will be described below with reference to FIGS. The shield conductive path A of the first embodiment includes a conductive path main body 10, a shield member 13 that exhibits a shielding function by surrounding the conductive path main body 10, and a tightening member 18 that surrounds the shield member 13. It is configured.

  The conductive path main body 10 is configured by a single covered electric wire in which a conductor 11 having a circular cross section is surrounded by a cylindrical insulating coating 12. The noise of the current flowing through the conductor 11 is canceled by the shield member 13. The tightening member 18 is constituted by a cylindrical heat-shrinkable tube that is deformed to be reduced in diameter when heated, a member in which an adhesive tape is wound spirally, and the like. The tightening member 18 presses the shield member 13 inward in the radial direction so that the shield member 13 is in close contact with the outer periphery of the conductive path main body 10, and also closely contacts the parallel shield wire 14 and the spiral shield wire 17 constituting the shield member 13 described later. It has a function.

  The shield member 13 is composed of four parallel shield wires 14 and one spiral shield wire 17. The four parallel shield wires 14 are all made of a metal wire having a circular cross section, and the outer diameters of the four parallel shield wires 14 are all the same. The four parallel shield wires 14 are routed along the outer periphery of the conductive path body 10 and substantially parallel to the axis of the conductive path body 10. Further, the four parallel shield wires 14 are arranged at a uniform pitch of approximately 90 ° in the circumferential direction. Both end portions of the four parallel shield wires 14 are grounded via ground members (not shown) such as terminal fittings and shield cases.

  The parallel shield wire 14 before being routed along the conductive path main body 10 is first formed into a linear shape, and then press-formed so as to form a substantially waveform having a constant wavelength. By this press molding, the parallel shield wire 14 is formed such that a plurality of crests 15 and troughs 16 are alternately arranged at a constant pitch in the length direction. The wavelengths of the waves of the four parallel shield lines 14 are all the same. Each parallel shield wire 14 is routed so that the peak portion 15 is separated from the outer periphery of the conductive path body 10 and the valley portion 16 is in contact with the outer periphery of the conductive path body 10. Then, in the axial direction of the conductive path main body 10, the phases of the waves of the four parallel shield wires 14 (the positions of the peak portions 15 and the valley portions 16) are shifted from each other in units of ¼ wavelength.

  The spiral shield wire 17 is made of a metal wire having a circular cross section. The outer diameter of the spiral shield wire 17 is the same as the outer diameter of the parallel shield wire 14. The spiral shield wire 17 is wound around the outer periphery of the conductive path body 10 in a spiral shape with a constant pitch. Both ends of the spiral shield wire 17 are grounded via a grounding member (not shown) like the parallel shield wire 14.

  As described above, the parallel shield wire 14 is routed so as to be parallel to the conductive path body 10, whereas the spiral shield wire 17 is routed so as to surround the conductive path body 10 in a spiral shape. The spiral shield wire 17 is in contact with the parallel shield wire 14 so as to intersect at the crest 15 and trough 16 of the wave. Each parallel shield wire 14 crosses the spiral shield wire 17 alternately inside and outside the spiral.

  That is, the crest 15 of the parallel shield wire 14 contacts the parallel shield wire 14 so as to intersect the outside of the spiral. In other words, the crest portion 15 of the parallel shield wire 14 sandwiches the spiral shield wire 17 with the outer periphery of the conductive path body 10 by the tightening action of the tightening member 18. Further, the valley portions 16 of the parallel shield wire 14 are in contact with the parallel shield wire 14 so as to intersect with each other inside the spiral. That is, the valley portion 16 of the parallel shield wire 14 is sandwiched between the spiral shield wire 17 and the conductive path body 10 by the tightening action of the tightening member 18. The parallel shield wire 14 and the spiral shield wire 17 are connected so as to be conductive by the tightening action of the tightening member 18.

  Since the parallel shield wire 14 is routed along the axis of the conductive path main body 10, the low frequency band noise superimposed on the conductive path main body 10 is canceled. The noise current of the parallel shield wire 14 is dropped to the ground. Further, since the spiral shield wire 17 is spirally arranged along the outer periphery of the conductive path main body 10, the high-frequency noise superimposed on the conductive path main body 10 is canceled.

  The noise current of the spiral shield wire 17 is also grounded in the same way as the parallel shield wire 14, but the spiral shield wire 17 has a coil shape and a high inductance. For this reason, the flow of the noise current becomes poor, and there is a concern that the noise canceling effect in the high frequency band is lowered. However, in the first embodiment, since the parallel shield wire 14 is in contact with the spiral shield wire 17 so as to be conductive at a plurality of locations, the noise current of the spiral shield wire 17 is grounded through the parallel shield wire 14. The Thereby, a good noise canceling effect can be obtained even in the high frequency band.

  As described above, the shield conductive path A according to the first embodiment includes the conductive path main body 10, the parallel shield wires 14 arranged so as to be parallel to the conductive path main body 10, and the spiral along the outer periphery of the conductive path main body 10. And a spiral shield wire 17 arranged in a shape. The spiral shield wire 17 contacts the parallel shield wire 14 in a crossed state. According to the shield conductive path A having such a configuration, the parallel shield wire 14 exhibits a good noise canceling effect in the low frequency band.

  Further, the noise current of the spiral shield wire 17 easily flows to the ground side through the parallel shield wire 14. That is, the parallel shield line 14 has a function as a drain line. Due to the drain function of the parallel shield wire 14, the spiral shield wire 17 can exhibit a good noise canceling effect in a high frequency band. Therefore, according to the shield conductive path A of the first embodiment, a sufficient noise canceling effect can be obtained in both the low and high frequency bands.

  Further, the shield conductive path A includes a cylindrical fastening member 18 that presses the spiral shield wire 17 and the parallel shield wire 14 radially inward toward the outer peripheral side of the conductive path main body 10. According to this configuration, the spiral shield wire 17 and the parallel shield wire 14 can be reliably brought into contact with each other by the pressing action of the fastening member 18. In the region where the parallel shield wire 14 and the spiral shield wire 17 are in contact with each other, the shield wires 14 and 17 are in close contact with each other by the pressing action of the fastening member 18. Therefore, even if a liquid such as water enters the inside of the cylindrical fastening member 18 (heat-shrinkable tube), the liquid does not sink into the contact area between the parallel shield wire 14 and the spiral shield wire 17, and the parallel The shield wire 14 and the spiral shield wire 17 are kept in contact with each other.

  Further, the parallel shield wire 14 is routed along a path that alternately crosses the spiral inside and outside of the spiral with respect to the spiral shield wire 17. According to this configuration, the spiral shield wire 17 and the parallel shield wire 14 can be prevented from being displaced away from the conductive path body 10 in the radial direction.

  Further, the parallel shield wire 14 is formed in a curved shape so as to have a substantially waveform, and the spiral shield wire 17 is in contact with the parallel shield wire 14 at the peak portion 15 and the valley portion 16 of the wave. According to this configuration, the spiral shield wire 17 is positioned by fitting into the wave crests 15 and valleys 16 of the parallel shield wire 14, so that the spiral pitch of the spiral shield wire 17 is stable so as to be constant. To do.

  Further, in the contact region between the parallel shield wire 14 and the spiral shield wire 17, the peak portion 15 and the valley portion 16 are curved and deformed along the outer peripheral surface of the spiral shield wire 17. Make line contact. Therefore, the contact area between the parallel shield wire 14 and the spiral shield wire 17 is secured wider than in the case of point contact. As a result, the noise current of the spiral shield wire 17 easily flows to the parallel shield wire 14.

<Example 2>
Next, a second embodiment of the present invention will be described with reference to FIG. The shield conductive path B of the second embodiment includes a conductive path main body 10, a shield member 20, and a tightening member 18. The conductive path main body 10, the spiral shield wire 17 constituting the shield member 20, and the tightening member 18 are all the same parts as in the first embodiment, and the operational effects are also the same as in the first embodiment. The same reference numerals are used, and detailed description is omitted.

  The shield member 20 includes the spiral shield wire 17 and four parallel shield wires 21. Each of the four parallel shield wires 21 is made of a metal wire having a circular cross section. The outer diameters of the wire materials used as the material of the four parallel shield wires 21 are all the same. The four parallel shield wires 21 are routed along the outer periphery of the conductive path body 10 and substantially parallel to the axis of the conductive path body 10. Further, the four parallel shield wires 21 are arranged at a uniform pitch of approximately 90 ° in the circumferential direction. Both ends of the four parallel shield wires 21 are grounded via ground members (not shown) such as terminal fittings and shield cases.

  The parallel shield wire 21 of the second embodiment is different from that of the first embodiment. In the shield conductive path A of the first embodiment, the parallel shield wire 14 is formed into a waveform, and the spiral shield wire 17 is fitted and brought into contact with the crest 15 and trough 16 of the wave. The pitch was stabilized. On the other hand, in the shield conductive path B of the second embodiment, a plurality of small diameter portions 22 that are partially thinned in a concentric circular cross section are formed in the contact area of the parallel shield wire 21 with the spiral shield wire 17. .

  The plurality of small diameter portions 22 are formed so as to be arranged at a constant pitch in the length direction of the conductive path main body 10 and the parallel shield wire 21. The arrangement pitch of the small diameter portions 22 in the four parallel shield wires 21 is all the same. In the axial direction of the conductive path main body 10, the positions of the small diameter portions 22 of the four parallel shield wires 21 are shifted from each other by a unit of ¼ of the arrangement pitch of the small diameter portions 22.

  As described above, the parallel shield wire 21 is arranged so as to be parallel to the conductive path main body 10, whereas the spiral shield wire 17 is arranged so as to surround the conductive path main body 10 in a spiral shape. The spiral shield wire 17 is in contact with the parallel shield wire 21 so as to intersect at a plurality of small diameter portions 22. Each parallel shield wire 21 crosses the spiral shield wire 17 alternately inside and outside the spiral. The parallel shield wire 21 and the spiral shield wire 17 are securely connected by the tightening action of the tightening member 18. Since the spiral shield wire 17 is positioned by fitting into the small diameter portion 22, the spiral pitch of the spiral shield wire 17 is stabilized.

  Further, in the contact region between the small diameter portion 22 and the spiral shield wire 17, the small diameter portion 22 is curved and deformed along the outer peripheral surface of the spiral shield wire 17, and thus makes a line contact with the outer peripheral surface of the spiral shield wire 17. Therefore, the contact area between the parallel shield wire 21 and the spiral shield wire 17 is secured wider than in the case of point contact. As a result, the noise current of the spiral shield wire 17 easily flows to the parallel shield wire 21.

<Other embodiments>
The present invention is not limited to the embodiments described with reference to the above description and drawings. For example, the following embodiments are also included in the technical scope of the present invention.
(1) As a means for positioning the spiral shield wire, the parallel shield wire is formed into a waveform in the first embodiment, and the small diameter portion is formed in the contact portion of the parallel shield wire with the spiral shield wire in the second embodiment. Not limited to this, a recess having a shape in which only a part in the circumferential direction is cut off may be formed on the outer periphery of the contact portion of the parallel shield wire with the spiral shield wire.
(2) In the first embodiment, the parallel shield wire is formed into a waveform, but the parallel shield wire may be formed so that the axis is linear.
(3) In the first and second embodiments, one parallel shield wire is routed along a path alternately traversing the inside and outside of the spiral with respect to the spiral shield wire. Alternatively, it may be routed along a path that crosses only the outside of the spiral of the spiral shield wire, and conversely, it may be routed along a path that crosses only the inside of the spiral of the spiral shield line. Also, when multiple parallel shielded wires are routed, parallel shielded wires that cross only the spiral outside of the spiral shielded wire and parallel shielded wires that cross only inside the spiral of the spiral shielded wire may be mixed. Good.
(4) In the first and second embodiments, the number of spiral shield wires is one, but a plurality of spiral shield wires may be provided.
(5) In the first and second embodiments, the spiral shield wire is spirally wound around one conductive path body. However, the present invention is not limited to this, and the spiral shield wire is spirally wound around a wire harness in which a plurality of conductive path bodies are bundled. It may be wound.
(6) In the first and second embodiments, four parallel shield wires are provided, but the number of parallel shield wires may be three or less or five or more.
(7) In Examples 1 and 2, the four parallel shield wires have the same outer diameter, but the four parallel shield wires have different outer diameters. Also good.
(8) In the first embodiment, the parallel shield wire and the spiral shield wire have the same outer diameter. However, the parallel shield wire and the spiral shield wire may have different outer diameters.
(9) Although the maximum outer diameter of the parallel shield wire and the outer diameter of the spiral shield wire are the same in the second embodiment, the maximum outer diameter of the parallel shield wire and the outer diameter of the spiral shield wire may be different from each other. Good.

A, B: shield conductive path 10: conductive path main body 14: parallel shield wire 15 ... mountain portion 16 ... valley portion 17 ... spiral shield wire 18 ... tightening member 21 ... parallel shield wire 22 ... small diameter portion

Claims (5)

A conductive path body;
A parallel shield wire arranged in parallel with the conductive path body;
A shield conductive path comprising a spiral shield line arranged in a spiral shape along an outer periphery of the conductive path main body and contacting the parallel shield line in a crossed state.   The shield conductive path according to claim 1, further comprising a cylindrical fastening member that presses the spiral shield line and the parallel shield line toward the outer periphery of the conductive path main body.   3. The shield conductive path according to claim 1, wherein the parallel shield line is routed along a path alternately traversing the inside and outside of the spiral with respect to the spiral shield line. The parallel shield wire is shaped into a curved shape so as to form a waveform.
4. The shield conductive path according to claim 3, wherein the spiral shield wire is in contact with the parallel shield wire at a peak portion and a valley portion of a wave.   The shield conductive path according to any one of claims 1 to 3, wherein a small-diameter portion that is partially thinned is formed in a contact portion of the parallel shield wire with the spiral shield wire.

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