JP2008131327A - Branch connection structure of communication line - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a branch connection structure which can sufficiently improve a waveform strain of a transmitted signal and can suppress an increase in manufacturing cost by a small number of components. <P>SOLUTION: In the branch connection structure of a communication line wherein branch lines are branched from a trunk line which constitutes a communication circuit, insulation coating is stripped off from terminals of the trunk line and branch lines to expose core lines and the exposed core lines of the trunk line and branch lines are terminal splice-connected by welding or terminal crimping to form a branch connection portion. At a position near the terminal splice portion, the trunk line and branch lines are converged and passed through a through hole of an attenuation element for attenuating a waveform strain of signals occurring in the branch connection portion. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a branch connection structure for communication lines, and more particularly to a branch connection structure having a function of reducing distortion of a transmission waveform generated at a branch part that branches a branch line from a trunk line of a communication network such as an in-vehicle LAN.

  In a communication network such as an in-vehicle network, when transmitting a signal from one communication device to another communication device, there is a problem that the transmission waveform is distorted due to electrical or magnetic noise and communication is not normally performed. is there. This waveform distortion is also caused by signal reflection mainly due to impedance mismatch, and it is inevitable that impedance mismatch occurs at the branch point of the communication line. For this reason, various techniques for improving waveform distortion at a branch point have been proposed.

  For example, as shown in FIG. 8, branch paths 92 connected to all the communication lines 91 branching in large numbers at the branch point of the branch connector 90 are inserted into the through holes of the ferrite beads 93, respectively. It has been proposed to reduce the distortion of the transmission waveform so that an inductive characteristic can be obtained in the branch path 92. The ferrite bead 93 and the branch path 92 are insulated by an insulating coating (not shown).

  Further, Patent Document 1 (Japanese Patent Publication No. 7-500463) discloses that between the branch points of the star-connected branch paths, that is, between the branch points of the pair of communication lines (CANH and CANL) constituting the CAN bus. In addition, it is described that, by providing a load impedance, it is terminated with a characteristic impedance of the communication line approximately at the branch portion when viewed from each communication line side. That is, it is described that the generation of a reflected wave caused by impedance mismatch in the branching portion is suppressed by setting the branching portion to the end of the communication line.

JP 7-700463 Gazette

  However, the branch connector 90 shown in FIG. 8 requires a bus bar for forming the branch path 92 and a connector housing for accommodating the bus bar, which increases the number of parts and increases the branch portion of the communication circuit. There's a problem.

  The present invention has been made in view of the above problems, and it is an object of the present invention to sufficiently improve the distortion of a transmission waveform with a smaller number of parts, suppress an increase in manufacturing cost, and reduce the size of a branch portion.

In order to solve the above problems, the present invention is a communication line branch connection structure in which a branch line branches from a main line constituting a communication circuit,
The core wire exposed from the insulation coating at the terminal of the main line and the terminal of the branch line are connected to each other by terminal splice by welding or terminal crimping to form a branch connection part,
A branch of a communication line, wherein the trunk line and the branch line are converged and passed through a through hole of an attenuation element that attenuates signal waveform distortion generated in the branch connection part at a position close to the terminal splice part. Provides a connection structure.

According to the branch connection structure of the communication line of the present invention, since the attenuation element is provided in the vicinity of the terminal splice part of the trunk line and the branch line of the communication line, the attenuation element absorbs the magnetic field generated in the vicinity of the branch connection part. By changing to heat, the high frequency component increased due to the mismatch of the branch portion can be reduced. In this way, it is possible to ideally improve the distortion of the transmission waveform that is likely to occur in the branch connection portion while having a simple configuration in which the terminal side that is the branch connection portion of the communication line is passed through one attenuation element, and The number of parts and the manufacturing cost can be reduced, and the branch connection portion can be made small.
In addition, the terminal of the said trunk line and a branch line shall also include the terminal formed by turning up the core wire exposed by peeling off the intermediate | middle skin | peel.
Moreover, in order to attenuate the signal waveform distortion generated in the branch connection portion by the attenuation element, it is preferable that 3 to 10 communication lines extend from the terminal splice portion.

The attenuation element is preferably formed of a ferrite core, ferrite rubber, a silicon steel plate, or permalloy.
According to the above configuration, since the attenuation element is formed of the soft magnetic material, it is possible to efficiently attenuate high-frequency signal waveform distortion generated at the branch connection portion.

It is preferable that the attenuation element is disposed within a range of 2 to 50 mm from the terminal splice part, and the trunk line and the branch line that are covered with insulation are passed through the through hole.
This is because if the attenuation element is located at a position closer than 2 mm from the branch connection portion, the attenuation element may be damaged when the splice connection is made. If the distance is greater than 50 mm, distortion of the transmission waveform at the branch portion is efficiently improved. Because you can't.

  A protective cap is put on the terminal splice part, the diameter of the protective cap is made larger than the diameter of the through hole provided in the attenuation element, and a stopper function for preventing the attenuation element from falling off is given to the protective cap. Is preferred.

  According to the above-described configuration, the terminal splice can be protected by the protective cap placed on the terminal splice, and the attenuation element can be prevented from coming off, and a structure for preventing the attenuation element from falling off is separately provided. There is no need to provide it.

When the communication line is composed of a pair of electric wires constituting a differential transmission line, the terminal side where the terminals of the first communication lines of the pair electric wires are spliced and the terminal side of which the terminals of the second communication lines are spliced Are respectively pierced through the cylindrical attenuation elements provided separately.
According to the above configuration, since the attenuation element is provided for each of the first and second communication lines, the attenuation element can be used for communication lines other than the paired wires, and the versatility of the attenuation element can be improved. .

Further, a terminal side where the terminals of the first communication lines of the paired wires are spliced and a terminal side where the terminals of the second communication lines are spliced are connected to each of the attenuation elements provided with two through holes. You may penetrate each hole.
According to the said structure, since it is possible to make one attenuation element even in the case of a pair electric wire, the number of parts and the manufacturing cost can be reduced.

  As described above, according to the present invention, it is possible to improve distortion of a signal waveform that easily occurs at a branch connection portion even though the attenuation element is provided in the vicinity of the terminal splice portion of the trunk line and the branch line of the communication line. In addition, the number of parts and the manufacturing cost can be reduced, and the branch connection portion can be reduced.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
1 to 3 show a first embodiment of the present invention.
A communication line branch connection structure 10 according to the present embodiment relates to a branch connection structure in which a branch line branches from a trunk line of a communication line 11 formed of a twisted pair electric wire constituting a communication line of an in-vehicle LAN represented by CAN.

  The communication line 11 is an electric wire in which the outer peripheral surface of a core wire 12 made of a conductor is covered with an insulating coating 13, and as shown in FIG. 1, a pair of first communication line 11H and second communication line 11L (CANH, CANL respectively) Corresponding to). In the present embodiment, two communication lines 11-1 (11H-1, 11L-1) constitute a trunk line of a communication circuit, while three communication lines 11-2 (11H-2, 11L-2) are included. Configure the branch line of the communication circuit.

  The terminal of the communication line 11 peels off the insulation coating 13 to expose the core wire 12, and the exposed core wires of all the first communication lines 11H (11H-1, 11H-2) constituting the trunk line and the branch line. The terminal splices 14H are formed by splicing 12 members together by ultrasonic welding. Similarly, the exposed core wires 12 of the second communication lines 11L (11L-1, 11L-2) are spliced together by ultrasonic welding to form a terminal splice portion 14L. In this way, by connecting the terminals of the first communication line 11H and the second communication line 11L of the communication line 11 to each other, a branch connection portion is formed in each of the first communication line 11H and the second communication line 11L. .

  The first communication line 11H and the second communication line 11L, in which the terminals are spliced to converge the main line and the branch line, are respectively passed through the through holes 15a of the cylindrical attenuation element 15 made of a ferrite core provided separately. The attenuation element 15 is arranged at a position 2 mm away from the tip of the terminal splice 14 of the terminal in the axial direction. That is, the attenuation element 15 is arranged at a position where the core wire 12 of the communication line 11 is covered with the insulating coating 13 and is not in contact with the core wire 12. In addition, the attenuation element 15 has a width corresponding to the axial direction of the communication line 11 of 3 to 10 mm, the outer diameter of the communication line 11 with the concentrated outer diameter +2 mm to +10 mm, and the same outer diameter as the communication line 11 with the focused inner diameter. Yes.

  Each of the terminal splice parts 14 (14H, 14L) is covered with a protective cap 16 made of resin and having a bottomed cylindrical shape. As shown in FIG. 3, the tape T is wound around the terminal of the communication line 11 to be attenuated. The element 15 and the protective cap 16 are fixed to the communication line 11. The diameter of the protective cap 16 is made larger than the diameter of the through hole 15a of the attenuation element 15 (the inner diameter) so that the attenuation element 15 does not fall off the end of the communication line 11 by the protective cap 16 even before the tape T is wound. Yes.

According to the above configuration, since the attenuation element 15 is provided in the vicinity of the terminal splice part 14 formed by splicing the trunk line 11-1 and the branch line 11-2 of the communication line 11, the attenuation element 15 is connected to the terminal splice part. 14 can absorb the magnetic field generated in the vicinity of 14 and convert it into heat, thereby reducing the high frequency component increased due to the mismatch of the branching portion. In this way, it is possible to ideally improve the distortion of the transmission waveform that is likely to occur at the branching portion while having a simple configuration in which the terminal side that is the terminal splice portion 14 of the communication line 11 is passed through the attenuation element 15, and Thus, the number of parts and the manufacturing cost can be reduced, and the branch portion can be prevented from being greatly increased.
The attenuation element 15 is not limited to a ferrite core, and may be formed of a soft magnetic material such as ferrite rubber, silicon steel plate, or permalloy.
Further, the terminal splice portion 14 is not limited to splice connection by ultrasonic welding, but may be splice connection by resistance welding or co-crimping by a crimp terminal described later.
Further, the fixing of the protective cap 16 to the communication line 11 is not limited to the tape winding fixing, and the protective cap may be fixed by heat shrinking or may be fixed by filling the protective cap with a water-stopping agent. Good. Moreover, you may accommodate the terminal part which attached the terminal splice part 14 and the attenuation element 15 in resin-made cases.

4 and 5 show a second embodiment of the present invention.
In this embodiment, the connection structure of the terminal splice part 14 and the shape of the attenuation element 15 are different from those of the first embodiment.
That is, as shown in FIG. 5, in this embodiment, the exposed core wire 12 of the end of the core wire 11 is crimped and connected by the crimp terminal 17 to form the terminal splice portion 14.
As shown in FIG. 4, two through holes 15 a are provided in one rectangular parallelepiped attenuation element 15, and the first communication line 11 </ b> H and the second communication line 11 </ b> L, each having a terminal connected to each through hole 15 a, are connected. Each is penetrated.

According to the above configuration, similarly to the first embodiment, the distortion of the transmission waveform that is easily generated at the branch portion can be ideally improved while being a simple configuration, and the first communication line 11H and the second communication line Since 11L penetrates through one attenuation element 15, the number of parts and the manufacturing cost can be further reduced.
In addition, since another structure and an effect are the same as that of 1st Embodiment, the same code | symbol is attached | subjected and description is abbreviate | omitted.

FIG. 6 shows a third embodiment of the present invention.
In the present embodiment, a pin-shaped attenuation element 18 made of a ferrite core is passed through the through hole 15 a of the cylindrical attenuation element 15 together with the communication line 11.
According to the said structure, the attenuation effect can be heightened with the other pin-shaped attenuation element 18 which let the attenuation element 15 pass, and distortion of a transmission waveform can be improved more.
In addition, since another structure and an effect are the same as that of 1st Embodiment, the same code | symbol is attached | subjected and description is abbreviate | omitted.

FIG. 7 shows a fourth embodiment of the present invention.
In the present embodiment, the insulation coating 13 of the trunk line 11-1 ′ and the required branch line 11-2 ′ is peeled off, the core wire 12 is exposed at the intermediate peeling position, and the exposed core wire 12 is bent. Forming a terminal.
The trunk line 11-1 ′, the branch line 11-2 ′, and the branch line 11-1 stripped by the same method as in the first embodiment are focused, and the core wire 12 is ultrasonically welded to form the terminal splice portion 14. Yes. Further, a position close to the terminal splice portion 14 is passed through the through hole 15 a of the attenuation element 15.

According to the said structure, since the insulation coating 13 of an electric wire is peeled off and folded at the intermediate peeling position to form a terminal, two electric wires can be formed with one electric wire. The number can be reduced.
In addition, since another structure and an effect are the same as that of 1st Embodiment, the same code | symbol is attached | subjected and description is abbreviate | omitted.

  The communication line branch connection structure of the present invention is suitably used for communication circuits such as in-vehicle LAN, OA (Office Automation), and FA (Factory Automation).

It is the schematic of the branch connection structure of the communication line of 1st Embodiment of this invention. It is a perspective view of a branch connection structure. It is sectional drawing of a branch connection structure. It is a perspective view of the branch connection structure of 2nd Embodiment of this invention. It is a perspective view of a terminal splice part. It is drawing which shows 3rd Embodiment of this invention. (A) (B) is drawing which shows 4th Embodiment of this invention. It is drawing which shows a prior art example.

Explanation of symbols

10 communication line branch connection structure 11 communication line 11-1 trunk line 11-2 branch line 11H (11H-1, 11H-2) first communication line 11L (11L-1, 11L-2) second communication line 14 terminal splice unit 15, 18 Attenuating element 16 Protective cap

Claims (6)

A branch connection structure of communication lines in which a branch line branches from a trunk line constituting a communication circuit,
The core wire exposed from the insulation coating at the terminal of the main line and the terminal of the branch line are connected to each other by terminal splice by welding or terminal crimping to form a branch connection part,
A branch of a communication line, wherein the trunk line and the branch line are converged and passed through a through hole of an attenuation element that attenuates signal waveform distortion generated in the branch connection part at a position close to the terminal splice part. Connection structure.   The communication line branch connection structure according to claim 1, wherein the attenuation element is formed of a ferrite core, ferrite rubber, a silicon steel plate, or permalloy.   The branch connection structure for a communication line according to claim 1 or 2, wherein the attenuation element is arranged in a range of 2 to 50 mm from the terminal splice part, and a trunk line and a branch line that are covered with insulation are passed through the through hole.   A protective cap is put on the terminal splice part, the diameter of the protective cap is made larger than the diameter of the through hole provided in the attenuation element, and a stopper function for preventing the attenuation element from falling off is given to the protective cap. The branch connection structure of the communication line according to any one of claims 1 to 3.   The communication line is composed of a pair of electric wires constituting a differential transmission line, and a terminal side in which the terminals of the first communication lines of the pair electric wires are spliced and a terminal side in which the terminals of the second communication lines are spliced are separately provided. The branch connection structure of the communication line according to any one of claims 1 to 4, wherein the structure is penetrated through the cylindrical attenuation element.   The communication line is composed of a pair of electric wires constituting a differential transmission line, and a terminal side in which the terminals of the first communication lines of the pair electric wires are spliced and a terminal side in which the terminals of the second communication lines are spliced are connected to 2 The branch connection structure for a communication line according to any one of claims 1 to 4, wherein each through hole of one attenuation element provided with two through holes is penetrated.

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