JP2012004082A - Shield wire and manufacturing method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a shield wire having a structure in which the shield wire is hard to break when passing through an extrusion machine, etc.SOLUTION: A shield wire 25 includes a core wire 21, a metal foil tape 22, and an insulation coating 23. The metal foil tape 22 is arranged along the outer peripheral surface of the core wire 21, and the plurality of metal foil tapes 22 are arranged in a longitudinal direction of the core wire 21. The insulation coating 23 has an electric insulation property, and is arranged along the outer peripheral surface of the metal foil tape 22. In addition, a boundary between the adjacent metal foil tapes 22 has a spiral shape.

Description

  The present invention mainly relates to a shielded electric wire in which a plurality of metal foil tapes are arranged in the longitudinal direction.

  Conventionally, a shielded electric wire composed of a core wire (wire material, core wire), a metal foil tape (shield foil tape), and an insulation coating is known. A core wire is comprised by what twisted the electric wire with a covering, for example. The metal foil tape is disposed outside the core wire, and is made of, for example, copper foil or aluminum foil. The insulating coating is disposed outside the metal foil tape and is made of synthetic resin or the like.

  This type of shielded electric wire can be manufactured using, for example, a manufacturing apparatus (tape forming apparatus, manufacturing apparatus for insulated wire) disclosed in Patent Documents 1 to 4 below.

  The tape forming apparatus of Patent Document 1 includes a guide roller, a vertically-attached cylindrical molding pipe, and a molding die as main components. The guide roller is for guiding the core wire and the metal foil tape. Then, the metal foil tape is introduced to the longitudinally-attached cylindrical molding pipe while being guided by the guide roller so as to be vertically attached onto the outer peripheral surface of the core wire. The metal foil tape is temporarily formed into a cylindrical shape so as to wrap the core wire in a vertically attached cylindrical forming pipe, and then finally formed into a cylindrical shape with a forming die. And insulation coating is shape | molded by extruding resin to the circumference | surroundings of metal foil tape with an extruder etc. FIG. A shielded electric wire can be manufactured as described above.

  The tape forming apparatus disclosed in Patent Document 2 discloses a method for manufacturing a shielded wire in the same manner as in Patent Document 1. In Patent Document 2, by forming a forming die (molding die) at an angle with respect to the take-up direction of the core wire, the hole of the forming die viewed from the take-off direction is made into an elliptical shape, and the core wire is The adhesive strength of the metal foil tape is increased. Therefore, it is possible to prevent the clogging in the hole of the forming die from occurring even during high speed molding.

  In the tape forming apparatus disclosed in Patent Document 3 and the insulated wire manufacturing apparatus disclosed in Patent Document 4, a shielded electric wire can be manufactured in the same manner as in Patent Document 1.

JP 2002-220159 A JP 2007-204204 A Japanese Patent Laid-Open No. 10-25065 JP 2009-181844 A

  By the way, as shown in Patent Document 3, the metal foil tape is supplied from a tape pad. The tape pad is composed of a central cylindrical member and a metal foil tape wound around the cylindrical member. And when the remaining amount of the metal foil tape wound around the cylindrical member is lost during the manufacture of the shielded electric wire, the end of the metal foil tape, the end of the metal foil tape supplied from the new tape pad, Is connected. In this way, production of shielded wires can be continued. In this connection, the metal foil tapes are not overlapped with each other in the thickness direction, and the adjacent metal foil tapes are arranged with a little space therebetween.

  However, the shielded electric wire may break when the boundary between the metal foil tapes passes through the extruder. Hereinafter, the reason will be described.

  First, the force received when the shielded wire passes through the extruder will be described. The shielded electric wire receives a tensile force from the winding side. Further, the shielded electric wire receives a pressing force from the extruder, and this pressing force is transmitted from the insulating coating to the inside (metal foil tape and core wire). Accordingly, a frictional force is generated between the insulating coating and the metal foil tape, and further a frictional force is generated between the metal foil tape and the core wire. By utilizing these frictional forces, the tensile force can be countered with an insulating coating, a metal foil tape, and a core wire.

  However, when the boundary of the metal foil tape reaches the extruder, there is no metal foil tape in this portion, so that the frictional force acting on the metal foil tape cannot be used to counter the tensile force. Therefore, in this case, the pressing force from the extruder is directly transmitted from the insulating coating to the core wire, and both are integrated by friction (that is, only the insulating coating and the core wire) to counter the tensile force. There must be. Therefore, the shielded electric wire may break at the boundary of the metal foil tape without completely resisting the tensile force.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide a shielded electric wire having a configuration that is difficult to break when passing through an extruder or the like.

Means and effects for solving the problems

  The problems to be solved by the present invention are as described above. Next, means for solving the problems and the effects thereof will be described.

  According to the 1st viewpoint of this invention, the shield electric wire of the following structures is provided. That is, this shielded electric wire includes a core wire, a metal foil tape, and an insulating coating. The said metal foil tape is arrange | positioned so that the outer peripheral surface of the said core wire may be followed, and several sheets are arranged in the longitudinal direction of the said core wire. The said insulation coating has electrical insulation and is arrange | positioned along the outer peripheral surface of the said metal foil tape. Further, the boundary between the adjacent metal foil tapes is spiral.

  That is, when manufacturing a shielded electric wire, the shielded electric wire may be pulled from the outside of the insulation coating and pulled to run in the longitudinal direction. In this regard, according to the above-described configuration, the boundary between the metal foil tapes has a longitudinal extension, and therefore, when the pressing portion reaches the boundary, the metal foil tape is always compressed through the insulation coating and the core wire. Therefore, the mechanical strength of the shielded wire does not decrease. Therefore, the breakage at the time of manufacturing the shielded electric wire can be prevented.

  In the shielded electric wire, the metal foil tapes are preferably connected to each other by a bonding tape parallel to the inclination of the boundary between the metal foil tapes.

  Thereby, metal foil tapes can be connected appropriately. Moreover, by adjusting the shape of the bonding tape, it is possible to suppress the occurrence of breakage of the shielded electric wire or to improve the strength of the connection portion between the metal foil tapes.

  According to the 2nd viewpoint of this invention, the manufacturing method of the following shielded electric wires is provided. That is, this method for manufacturing a shielded electric wire includes a metal foil forming step and a covering forming step. In the metal foil forming step, a metal foil tape is formed so as to wrap the traveling core wire. In the coating forming step, an insulating coating is formed by extruding a resin around the metal foil tape. Moreover, when arranging at least two pieces of the metal foil tape in the longitudinal direction of the metal foil tape in the previous stage of the metal foil molding step, the boundary between the adjacent metal foil tapes is the boundary of the metal foil tape. Inclined with respect to a line perpendicular to the longitudinal direction.

  That is, in the covering molding process, the shielded electric wire is pressed from the outside of the insulating coating, and the shielded electric wire is pulled to run in the longitudinal direction. In this regard, according to the above-described configuration, the boundary between the metal foil tapes has a longitudinal extension, and therefore, when the pressing portion reaches the boundary, the metal foil tape is always compressed through the insulation coating and the core wire. Since it is integrated by force, the mechanical strength of the shielded wire does not decrease. Therefore, breakage in the coating molding process can be prevented.

Schematic which showed the whole structure of the electric wire covering line for manufacturing the covered electric wire of this invention. The perspective view which showed the structure which shape | molds a metal foil tape and insulation coating on the outer peripheral surface of a core wire. The figure which shows the shape of the boundary of the metal foil tape in the past. The figure which shows the shape of the boundary of the metal foil tape in this embodiment. The figure which shows the state which the conventional shield wire of this embodiment received the pressing force. The figure which shows the shape of the metal foil tape used for intensity | strength comparison, and a joining tape.

  Next, embodiments of the invention will be described. FIG. 1 is a schematic view showing an overall configuration of an electric wire covering line 1 including an extruder according to an embodiment of the present invention. FIG. 2 is a perspective view showing a configuration in which the metal foil tape 22 and the insulating coating 23 are formed on the outer peripheral surface of the core wire 21.

  An electric wire covering line 1 shown in FIG. 1 is an apparatus for manufacturing a shield electric wire 25, and includes a supply stand 10, a metal foil tape supply device 11, a tape processing device 12, an extruder 13, a water tank 14, and a take-up. Machine 15, accumulator 16, and gripping machine 17.

  The supply stand 10 is configured to send the core wire 21 toward the tape processing device 12 and the extruder 13 on the downstream side. In the present embodiment, the core wire 21 is formed by twisting a pair of covered electric wires.

  The metal foil tape supply device 11 has a cylindrical member around which the metal foil tape 22 is wound. Then, the metal foil tape 22 wound around the cylindrical member is sent toward the tape processing device 12. Further, when the metal foil tape 22 wound around the cylindrical member is lost, the end of the metal foil tape 22 and the end of the metal foil tape 22 wound around the new cylindrical member are connected. In addition, as the metal foil tape 22, it is preferable to use a conductive foil (for example, a metal foil such as an aluminum foil or a copper foil) in a tape shape, or a laminate of a resin film such as polyester on the conductive foil. it can.

  The tape processing device 12 is configured to wind the metal foil tape 22 around the core wire 21. The tape processing apparatus 12 includes a plurality of guide rollers 41 to 44, a first die 51, and a second die 52.

  The guide roller 41 guides the core wire 21, and the guide roller 42 guides the metal foil tape 22. The guide rollers 43 and 44 are configured not to rotate spontaneously in order to fix the positions of the core wire 21 and the metal foil tape 22 and prevent displacement in the take-up direction (longitudinal direction).

  The first die 51 is temporarily formed into a cylindrical shape by passing the metal foil tape 22 together with the core wire 21 so that both ends in the width direction of the metal foil tape 22 overlap each other. The second die 52 finally forms the metal foil tape 22 by passing the metal foil tape 22 after passing through the first die 51 together with the core wire 21. A metal foil forming process for forming the metal foil tape 22 is realized by the tape processing apparatus 12 having the above configuration.

  The extruder 13 extrudes a synthetic resin around the metal foil tape 22 disposed outside the core wire 21 to form a coating (sheath). The extruder 13 includes a kneading chamber (not shown), a screw disposed in the kneading chamber, and a crosshead type extrusion die 31 connected to one end of the kneading chamber.

  With this configuration, when a compound as a coating material is supplied to the extruder 13, the compound is kneaded inside the kneading chamber by driving a screw and heated by a heater (not shown), and the molten resin is added to the extrusion die. Extruded through 31.

  As a result, the insulating coating 23 can be formed by extruding the resin around the metal foil tape 22 passing through the extrusion die 31. The coating molding process is realized as described above. In addition, as resin used here, a polypropylene, polyvinyl chloride, etc. can be used.

  The shielded electric wire 25 can be manufactured through this covering molding process. The shielded electric wire 25 includes a core wire 21, a metal foil tape 22, and an insulating coating 23 in order from the inside. And the shield electric wire 25 pushed out from the extrusion die 31 is cooled by passing through the water tank 14, and then, via the take-up machine 15 for pulling and running the shield electric wire 25 from the upstream side, the gripping machine 17. And is shaped into a coil.

  The accumulator 16 is configured to be able to store the shielded electric wire 25 as appropriate and to change the storage length. And, for example, when the supply of the electric wire to the gripping machine 17 is stopped in order to remove the coiled electric wire from the gripping machine 17, by increasing the storage length of the shielded electric wire 25 in the accumulator 16, The slackness of the shielded electric wire 25 continuously supplied from the upstream side can be prevented.

  Next, the shape of the boundary between the metal foil tape 22 wound around the cylindrical member and the metal foil tape 22 wound around the new cylindrical member will be described. First, the shape of the boundary between metal foil tapes in the related art will be described with reference to FIG. FIG. 3 is a diagram showing the shape of the boundary of the conventional metal foil tape 22x. Note that, in the conventional example described below, the core wire and the insulation coating are the same as those of the present embodiment, and thus are denoted by the same reference numerals. Further, since the shape of the metal foil tape is different from that of the present embodiment, the metal foil tape is denoted by reference numeral 22x, and the shielded electric wire provided with the metal foil tape 22x is denoted by reference numeral 25x.

  First, the configuration of the metal foil tape 22x before covering the core wire 21 will be described with reference to FIG. FIG. 3A is a diagram showing the boundary between the metal foil tapes 22x before covering the core wire 21. FIG. Further, FIG. 3 (a) and FIG. 4 (a) to be described later depict the metal foil tape before covering the core wire 21, but when the metal foil tape of the shielded electric wire is developed in a planar shape. It can also be expressed as a diagram showing the boundary between the metal foil tapes.

  As shown in FIG. 3A, conventionally, the longitudinal ends of the adjacent metal foil tapes 22x are perpendicular to the longitudinal direction. The metal foil tape 22x is arranged so that the ends face each other. In the boundary portion, the metal foil tapes 22x are not stacked in the thickness direction, and the adjacent metal foil tapes 22x are arranged with a slight gap in the longitudinal direction of the shielded electric wire 25x.

  Next, with reference to FIG.3 (b) and FIG.3 (c), the shape of the metal foil tape 22x after shape | molding the shield electric wire 25x is demonstrated. FIG. 3B is a diagram when the shielded electric wire 25x is viewed in a direction perpendicular to the longitudinal direction. FIG.3 (c) is the AA sectional drawing and BB sectional drawing in FIG.3 (b).

  In the case of the conventional shielded electric wire 25x, except for the boundary portion between the metal foil tapes, the cross section includes the core wire 21 and the metal foil tape as shown in the AA sectional view of FIG. 22x and insulating coating 23 appear. As the metal foil tape 22x is formed by the tape processing device 12 so as to wrap the core wire 21, both ends in the width direction of the metal foil tape 22x are overlapped in the thickness direction. In the cross-sectional view, such overlapping portions are omitted and are simply illustrated.

  Then, at the boundary between the metal foil tapes 22x adjacent in the longitudinal direction of the shielded electric wire 25x, the metal foil tapes 22x are slightly separated in the longitudinal direction of the shielded electric wire 25x as described above. For this reason, only the core wire 21 and the insulation coating 23 appear in the cross section of the shielded electric wire 25x as shown in the BB cross section of FIG. In other words, an annular boundary (gap) is formed between the cylindrical metal foil tapes 22x, and the gap is filled with the resin of the insulating coating 23.

  Next, the shape of the boundary between the metal foil tapes 22 in this embodiment will be described with reference to FIG. FIG. 4 is a diagram showing the shape of the boundary of the metal foil tape 22 in the present embodiment.

  First, the metal foil tape 22 before covering the core wire 21 will be described with reference to FIG. FIG. 4A is a diagram showing the boundary of the metal foil tape 22 before covering the core wire 21. As shown in FIG. 4 (a), both ends in the longitudinal direction of each metal foil tape 22 have an inclined straight outline rather than a right angle as in the prior art. The contour of the end portion is inclined with respect to the longitudinal direction of the metal foil tape 22 and is also inclined with respect to a line perpendicular to the longitudinal direction of the metal foil tape 22. And the some metal foil tape 22 is arrange | positioned so that this inclined edge part may become parallel. In addition, the edge parts of the metal foil tape 22 may be connected by the below-mentioned joining tape etc.

  Next, with reference to FIG.4 (b) and FIG.4 (c), the shape of the metal foil tape 22 after shape | molding the shield electric wire 25 is demonstrated. FIG. 4B is a diagram when the shielded electric wire 25 is viewed in a direction perpendicular to the longitudinal direction. FIG.4 (c) is CC sectional drawing and DD sectional drawing in FIG.4 (b).

  As shown in FIG. 4B, the boundary of the metal foil tape 22 in the shielded electric wire 25 is spiral, and the spiral of the boundary is outside the core wire 21 within a certain range in the longitudinal direction of the shielded electric wire 25. Is going around 1 round. For this reason, in the shielded electric wire 25 of the present embodiment, the boundary portion (excluding the spiral end) is cut perpendicularly to the longitudinal direction of the shielded electric wire 25, as shown in FIG. The core wire 21, the two metal foil tapes 22, and the insulation coating 23 appear. In this cross section, a gap in the circumferential direction is generated between the two metal foil tapes 22 at a portion corresponding to the spiral boundary, but the size is slight.

  Next, with reference to FIG. 5, the disconnection which generate | occur | produces when the shield electric wire 25 of this embodiment and the conventional shield electric wire 25x pass the extruder 13 in the said coating | covering process is demonstrated. FIG. 5 is a diagram illustrating a state in which a pressing force is applied to the shielded electric wire 25 and the shielded electric wire 25x.

  As described above, the shielded electric wires 25 and 25x are traveling by receiving a tensile force from the winding side. In addition, the shielded wires 25 and 25x receive a pressing force from the crosshead type extrusion die 31 in the covering process. This compression force is transmitted from the insulating coating 23 to the inside (the metal foil tapes 22 and 22x and the core wire 21).

  Consider a case where the pressing force is applied to a portion (for example, a portion indicated by line AA in FIG. 3B) other than the boundary of the metal foil tape 22x in the shielded electric wire 25x having the conventional configuration. In this case, the compression force is sequentially transmitted from the insulating coating 23 to the metal foil tape 22x and from the metal foil tape 22x to the core wire 21 in the left sectional view of FIG. Therefore, a frictional force is generated against the displacement in the longitudinal direction between the insulating coating 23 and the metal foil tape 22x and between the metal foil tape 22x and the core wire 21. As a result, the insulating coating 23, the metal foil tape 22x, and the core wire 21 are well integrated with each other by a frictional force, so that the tensile force can be strongly countered.

  However, when this pressing force is applied to the portion of line BB in FIG. 3B, the metal foil tape 22x does not exist in this portion as shown in FIG. 3C. The compression force is transmitted from the insulation coating 23 to the core wire 21 as shown on the right side of FIG. 5A, and the insulation coating 23 and the core wire 21 are integrated by a frictional force to resist the pulling side pulling force. It will be. Therefore, the shield wire 25x is a portion of the BB line, and the tensile strength is greatly reduced locally by the amount that the drag of the metal foil tape 22x cannot be used, and the portion is easily broken.

  In this regard, the shielded electric wire 25 of the present embodiment is such that the two metal foil tapes 22 as a whole have a circle of approximately 360 ° as shown in FIG. 4C at any part of the boundary between the metal foil tapes 22. It is formed in an arc shape close to the ring and is sandwiched between the insulating coating 23 and the core wire 21. Therefore, no matter which part of the boundary is pressed, the insulation coating 23, the two metal foil tapes 22, and the core wire 21 are well integrated on the basis of the frictional force generated by the compression, and the winding is performed. It can counter the pulling force on the take-off side. As a result, it can be avoided that the tensile strength is greatly reduced locally at the boundary of the metal foil tape 22, and the shielded electric wire 25 can be prevented from being broken in the covering step.

  Next, an experiment conducted by the inventor of the present application to examine the influence of the angle of the end portion of the metal foil tape 22 and the shape of the joining tape applied to the boundary on the strength and the like of the shielded electric wire 25 will be described with reference to FIG. To do.

  In this experiment, the shielded electric wire 25 was manufactured by the electric wire covering line 1 described above by changing the angle of the boundary between the metal foil tapes 22 and the shape of the bonding tape 60, and the frequency of occurrence of breakage was examined. . An example of the metal foil tape 22 and the joining tape 60 used here is shown in FIGS. In addition, all the joining tapes 60 used here are affixed in parallel with the angle of the boundary between the metal foil tapes 22. In this experiment, a resin bonding tape 60 is used.

  As a result, when the conventional shielded electric wire 25x is used, breakage frequently occurs. For example, the configuration shown in FIG. 6A (tape thickness 25 μm, tape width 25 mm, and tape angle (metal foil tape) At the angle between the 22 boundaries (45 °), there was almost no disconnection. That is, it can be said that the effect of the present invention has been confirmed.

  In the configurations from (b) to (e) in FIG. 6, no disconnection occurred. When the tensile strengths of the configurations of (d) and (e) were compared, the configuration of (d) had a higher tensile strength than the configuration of (e).

  In addition, from this experiment, it can be seen that the metal foil tape 22 of 30 ° can suppress the occurrence of disconnection better than the metal foil tape 22 of 45 ° tape angle (that is, the angle between the metal foil tapes 22). I understood. Further, it was found that the metal foil tape 22 with a tape width of 10 mm can suppress the occurrence of disconnection than the metal foil tape 22 with a tape width of 25 mm.

  As described above, the shielded electric wire 25 of the present embodiment includes the core wire 21, the metal foil tape 22, and the insulating coating 23. The metal foil tape 22 is disposed along the outer peripheral surface of the core wire 21, and a plurality of the metal foil tapes 22 are arranged in the longitudinal direction of the core wire 21. The insulating coating 23 has electrical insulation and is disposed along the outer peripheral surface of the metal foil tape 22. Moreover, the boundary between adjacent metal foil tapes 22 is spiral.

  Moreover, in this embodiment, the shielded electric wire 25 is manufactured by the method shown below. That is, this manufacturing method includes a metal foil forming step and a coating forming step. In the metal foil forming step, the metal foil tape 22 is formed so as to wrap the traveling core wire 21. In the coating molding process, the insulating coating 23 is molded by extruding a resin around the metal foil tape 22. Further, when arranging at least two metal foil tapes 22 in the longitudinal direction of the metal foil tape 22 in the previous stage of the metal foil forming step, the boundary between the adjacent metal foil tapes 22 is the metal foil tape 22. It is inclined with respect to a line perpendicular to the longitudinal direction.

  As a result, since the boundary between the metal foil tapes 22 extends in the longitudinal direction, the metal foil tape 22 is always integrated by the compression via the insulating coating 23 and the core wire 21 when the pressed portion reaches the boundary. Therefore, the mechanical strength of the shielded electric wire 25 does not decrease. Therefore, the breakage at the time of manufacturing the shielded electric wire 25 can be prevented.

  Moreover, in the shielded electric wire 25 of the present embodiment, the metal foil tapes 22 are connected to each other by a bonding tape parallel to the inclination of the boundary between the metal foil tapes 22.

  Thereby, metal foil tapes 22 can be connected appropriately. Moreover, by adjusting the shape of the bonding tape, it is possible to suppress the breakage of the shielded electric wire 25 or to improve the strength of the connection portion between the metal foil tapes 22.

  The preferred embodiment of the present invention has been described above, but the above configuration can be modified as follows, for example.

  As an angle formed by the boundary between the metal foil tapes 22 and the longitudinal direction of the metal foil tapes 22 has been experimentally described as being 30 °, other angles may be used. However, this angle is preferably 20 ° or more and 40 ° or less from the viewpoint of favorably preventing breakage.

  The core wire 21 supplied from the supply stand 10 is not limited to a twisted pair of electric wires, and various other forms of electric wires can be adopted as the core wires.

  Instead of the guide rollers 41 to 44, the metal foil tape 22 can be changed to be guided so as to be attached to the core wire 21 by appropriate guide means such as a guide sleeve.

DESCRIPTION OF SYMBOLS 1 Electric wire coating line 11 Metal foil tape supply apparatus 12 Tape processing apparatus 13 Extruder 21 Core wire 22,22x Metal foil tape 23 Insulation coating 25,25x Shielded electric wire 60 Joining tape

Claims (3)

With the heart
A metal foil tape that is arranged along the outer peripheral surface of the core wire, and a plurality of sheets are arranged in the longitudinal direction of the core wire;
Insulating coating that has electrical insulation and is disposed along the outer peripheral surface of the metal foil tape;
With
A shielded electric wire, wherein a boundary between adjacent metal foil tapes is spiral. The shielded electric wire according to claim 1,
The shielded electric wires characterized in that the metal foil tapes are connected to each other by a joining tape parallel to the inclination of the boundary between the metal foil tapes. A metal foil forming process for forming a metal foil tape so as to wrap the running core;
A coating molding step of molding an insulating coating by extruding a resin around the metal foil tape;
Including
When arranging at least two pieces of the metal foil tape in the longitudinal direction of the metal foil tape in the previous stage of the metal foil forming step, the boundary between the adjacent metal foil tapes is the longitudinal direction of the metal foil tape. A method of manufacturing a shielded wire, wherein the shielded wire is inclined with respect to a line perpendicular to the line.

Images