JP2007196498A - Extrusion die structure for electric wire - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an extrusion die structure for an electric wire which can reduce protrusion in extrusion molding, and at the same time, which can mold a product having no flaw on the surface. <P>SOLUTION: This extrusion die 11 for the electric wire is equipped with the extrusion die 12 having a flow passage 15 for a thermoplastic resin member, and an extrusion nipple 13 which is arranged in the flow passage, and inserts and carries a wire material to be coated. The flow passage 15 has a flow passage section 16 of which the diameter contracts in a tapered shape from an inlet section 16a, and a flow passage section 17 of a specified diameter which communicates with the flow passage. The opening angle of the flow passage section 16 is set to be 25° to 35°, the inner diameter of the flow passage section 17 is set to be one to two times of the outer diameter of a product, and the length is set to be 3 mm to 4 mm. The extrusion nipple 13 has a tapered section 13b of which the diameter contracts in a tapered shape from the inlet of the flow passage 15, and a cylindrical section 13c of a specified diameter which is connected with the tapered section. Then, the opening angle of the tapered section is set to be 10° to 20°, and the length of the cylindrical section is set to be 4 mm to 5 mm. Also, the end surfaces of the outlet sections of the flow passage section 17 and the cylindrical section 13c are set to be flush with the structure of the extrusion die. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an extrusion mold structure for electric wires used for extrusion molding of electric wires such as shielded electric wires.

  Due to recent environmental problems, olefin-based members (halogen-free) are being used from PVC (polyvinyl chloride) members as insulating materials for electric wires (wire harnesses) for automobiles. When an olefin-based member is extruded as an insulating material for an electric wire for automobiles, the occurrence of a scum (resin residue) was not observed in the conventional PVC member, but a sag during the extrusion was easily generated due to the characteristics of the material. . When the generated sealant adheres to the surface of the cable covered, there is a problem that not only the external fitting of the cable is impaired but also the workability of the wire harness (W / H) becomes extremely difficult.

In order to solve such a problem, the radius of curvature is 0.1 mm or more at the outlet portion 2 of the hole portion 4 forming the flow path F of the molten thermoplastic resin member of the extruder die 1 as shown in FIG. A trumpet-shaped first curved wall (R portion) 5 that is less than 10 mm is formed, and a trumpet-shaped second curved wall (R portion) 8 that has a radius of curvature of 0.1 mm or more at the die entrance portion 6. An extrusion die is proposed in which the removal process of the spear is reduced and a product having no scratch on the cable surface is formed (see, for example, Patent Document 1).
Japanese Patent Laid-Open No. 11-34141 (page 3, FIG. 1)

  However, the die for an extruder having the above structure increases the cost for manufacturing the first and second curved portions (R portion) at the inlet portion and the outlet portion of the flow path of the thermoplastic resin member. However, it is not suitable for pipe extrusion production, and is not sufficient for prevention of mess. For this reason, there are problems that many defective products are generated in the manufacturing process of the shielded wire, the yield is poor, and the product cost is increased.

  The present invention has been made in view of the above-described points, and an object of the present invention is to provide an electric wire extrusion mold structure capable of reducing the occurrence of a crack during extrusion molding and molding a product having no scratch on the surface. .

  In order to achieve the above object, an extrusion die structure for an electric wire according to the present invention includes an extrusion die having a flow path of a thermoplastic resin member, and a wire rod that is concentrically arranged in the flow path and is to be covered. And an extrusion mold structure of an electric wire that covers the wire with the thermoplastic resin member by extrusion molding, and the flow path of the extrusion die is tapered from the inlet portion. A first flow path section and a second flow path section having a predetermined diameter communicating with the first flow path, and an opening angle of the first flow path section is set to 25 degrees to 35 degrees; The inner diameter of the flow channel is set to 1 to 2 times the outer diameter of the product and the length is set to 3 mm to 4 mm. The extrusion nipple is tapered from the inlet side of the flow channel, and the taper. A cylindrical portion of a predetermined diameter connected to the portion, and the opening angle of the tapered portion is 10 degrees to 20 degrees, the front The length of the cylindrical portion is set to 4 mm to 5 mm, and the outlet end surface of the second flow path portion of the extrusion die and the outlet portion end surface of the cylindrical portion of the extrusion nipple are set on the same plane. It is said.

  The wire to be coated is inserted and conveyed into the extrusion nipple, and a molten thermoplastic resin member as a coating material is supplied to the flow path of the extrusion die to coat the wire. The opening angle of the first flow path part of the extrusion die is set to 25 to 35 degrees, the inner diameter of the second flow path part is set to 1 to 2 times the outer diameter of the product, and the length is set to 3 mm to 4 mm. The opening angle of the taper part is set to 10 to 20 degrees, the length of the cylindrical part is set to 4 mm to 5 mm, and the end face of the outlet part of the second flow path part of the extrusion die and the cylindrical part of the extrusion nipple Are set on the same surface, the occurrence of a seal (resin residue) on the mold exit side is prevented, and a product having no scratch on the cable surface can be formed.

  The wire extrusion mold structure according to claim 2 of the present invention is the wire extrusion mold structure according to claim 1, wherein the thermoplastic resin member is an olefin resin member. Yes.

  By restricting the structure of the extrusion die and the extrusion nipple as described above, even when an olefin-based resin member is used as the coating material for the electric wire, the occurrence of a resin (resin residue) is prevented. Thereby, pipe | tube extrusion manufacture like a shielded electric wire is attained.

  According to the present invention, since the R portion is not provided at the inlet portion and the outlet portion of the flow path of the extrusion die, it is possible to provide a die that has a simple structure and is capable of suppressing an increase in cost and is less expensive. In addition, by newly defining the nipple configuration for extrusion, it becomes possible to reduce the occurrence of scum (resin residue), and the work of removing scum is further reduced, and the surface of the surface is reduced by reducing the generation of scum. This makes it possible to mold a product without any problem and to produce a stable product. This eliminates the poor yield and makes it possible to manufacture products at low cost.

  Hereinafter, the best embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 shows a cross section of an extrusion die structure of an electric wire according to the present invention. An extrusion die 11 includes an extrusion die 12 and an extrusion nipple (mandrel) 13. The extrusion die 12 has a cylindrical shape, and a flow path 15 of a thermoplastic resin member melted from one end (inlet side) end surface 12a to the other side (outlet side) end surface 12b is formed through the center.

  The flow path 15 includes an inlet-side flow path section (first flow path section) 16 and an outlet-side flow path section (second flow path section) 17, and the flow path section 16 extends from the inlet section 16 a to the flow path section. The inner wall surface 16 b is formed in a tapered shape with a predetermined opening angle α up to the communicating portion with 17. The flow path part 17 has a predetermined inner diameter D, and the outlet part 17b opens to the end face 12b. And this flow-path part 17 is set to predetermined length Lb from the end surface 12b of the exit part 17b.

  The extrusion nipple 13 is arranged concentrically with an annular space at the center of the flow path 15. The distal end portion 13a of the extrusion nipple 13 has a shape substantially corresponding to the shape of the flow path 15 of the extrusion die 12, and the diameter of the flow path portion 16 is reduced from the end face 12a side of the extrusion die 12 in a tapered shape. The taper portion 13b is opposed to the inner wall surface 16b, and the cylindrical portion 13c is connected to the taper portion 13b and penetrates the flow passage portion 17. The end surface 13e of the outlet portion 13d of the cylindrical portion 13c is flush with the end surface of the outlet portion 17b of the flow channel portion 17, that is, the end surface 12b of the extrusion die 12, and has a predetermined length Lc (> Lb) from the end surface 12b. Is set to Further, the outer peripheral surface 13f of the tapered portion 13b is set to a predetermined opening angle β (<α).

  The inner diameter (exit diameter) D of the flow path portion 17 is set to be 1-2 times larger than the product outer diameter. Preferably, it is about 1.7 to 1.8 times. Further, the length (land length) Lb of the flow path portion 17 is set to 3 mm to 4 mm. The opening angle α of the inner wall surface 16b of the flow path portion 16 is set to 25 degrees to 35 degrees. The length (land length) Lc of the cylindrical portion 13c of the extrusion nipple 13 is set to 4 mm to 5 mm, and the opening angle β of the outer peripheral surface 13f of the tapered portion 13b is set to 10 degrees to 20 degrees.

  In the extrusion die 11 having the above structure, a wire to be coated (not shown) is conveyed in the extrusion nipple 13 from the tapered portion 13b side to the cylindrical portion 13c side as indicated by an arrow A, and melted heat to be coated (not shown). A plastic resin member such as an olefin resin member is supplied to the flow path 15 as indicated by an arrow B to coat and mold the wire.

  Next, an embodiment of the extrusion die 1 having the above structure will be described.

1. About the exit diameter (inner diameter) D of the flow passage portion 17 of the extrusion die 12 (i) The amount of occurrence of the sag at the outlet portion 17b of the flow passage portion 17 of the extrusion die 12 is 360 stages from the start of extrusion in five stages. Table 1 shows the results of the evaluation (evaluated in five stages from 1, 2, 3, 4 and 5 from those with a small amount of mains).

（ii）製品へのメヤニ付着状態を表２に示す。

(Ii) Table 2 shows the state of adherence to the product.

上記検証結果より、流路部１７の出口径Ｄは、製品外径の１〜２倍程度、好ましくは１.７〜１.８倍程度であることが分かった。
２．流路部１７の長さ（ランド長さ）Ｌbについて
（i）押出用ダイ１２の流路部１７の出口部１７ｂのメヤニ発生量を押出開始から３６０ｍ製造直後の状態について５段階で評価（メヤニ量の少ないものから１・２・３・４・５として５段階で評価）した結果を表３に示す。

From the above verification results, it was found that the outlet diameter D of the flow channel portion 17 was about 1 to 2 times, preferably about 1.7 to 1.8 times the product outer diameter.
2. About the length (land length) Lb of the flow path portion 17 (i) Evaluation of the amount of occurrence of the sealant at the outlet portion 17b of the flow path portion 17 of the extrusion die 12 in five stages from the start of extrusion to 360 m (manifold) Table 3 shows the results of evaluation in five levels from 1, 2, 3, 4, and 5 in ascending order.

（ii）製品へのメヤニ付着数（３６０ｍ製造時）を表４に示す。

(Ii) Table 4 shows the number of sticking to the product (at the time of manufacturing 360 m).

上記検証結果より、流路部１７の長さ（ランド長さ）Ｌbは、３ｍｍ〜４ｍｍ程度が好ましいことが分かった。
３．押出用ダイ１２の流路部１６のテーパ状の内壁面１６ｂの開き角度αについて
（i）押出用ダイ１２の流路部１７の出口部１７ｂのメヤニ発生量を押出開始から３６０ｍ製造直後の状態について５段階で評価（メヤニ量の少ないものから１・２・３・４・５として５段階で評価）した結果を表５に示す。

From the verification result, it was found that the length (land length) Lb of the flow path portion 17 is preferably about 3 mm to 4 mm.
3. The opening angle α of the tapered inner wall surface 16b of the flow passage portion 16 of the extrusion die 12 (i) A state immediately after the start of extrusion of 360 m from the start of extrusion, the amount of occurrence of the sag at the outlet portion 17b of the flow passage portion 17 of the extrusion die 12 Table 5 shows the results of evaluation in 5 stages (evaluated in 5 stages from 1, 2, 3, 4 and 5 from the one with the least amount of mains).

（ii）製品へのメヤニ付着数（３６０ｍ製造時）を表６に示す。

(Ii) Table 6 shows the number of spears attached to the product (at the time of production of 360 m).

上記検証結果より、流路部１６の内壁面１６ｂの開き角度αは、２５度〜３５度が好ましいことが分かった。
４．押出用ニップル１３の円筒部１３ｃの長さ（ランド長さ）Ｌcについて
（i）押出用ダイ１２の流路部１７の出口部１７ｂのメヤニ発生量を押出開始から３６０ｍ製造直後の状態について５段階で評価（メヤニ量の少ないものから１・２・３・４・５として５段階で評価）した結果を表７に示す。

From the above verification results, it was found that the opening angle α of the inner wall surface 16b of the flow path portion 16 is preferably 25 degrees to 35 degrees.
4). About the length (land length) Lc of the cylindrical portion 13c of the extrusion nipple 13 (i) The amount of occurrence of the sag at the outlet portion 17b of the flow passage portion 17 of the extrusion die 12 is five stages from the start of extrusion to a state immediately after production of 360 m. Table 7 shows the results of the evaluation in (Evaluated in 5 stages from 1,2,3,4,5 from the one with the least amount of mains).

（ii）製品へのメヤニ付着数（３６０ｍ製造時）を表８に示す。

(Ii) Table 8 shows the number of spots on the product (when manufacturing 360 m).

上記検証結果より、円筒部１３ｃの長さ（ランド長さ）Ｌcは、４ｍｍ〜５ｍｍ程度が好ましいことが分かった。
５．押出用ニップル１３のテーパ部１３ｂの外周面１３ｆの開き角度βについて
（i）押出用ダイ１２の流路部１７の出口部１７ｂのメヤニ発生量を押出開始から３６０ｍ製造直後の状態について５段階で評価（メヤニ量の少ないものから１・２・３・４・５として５段階で評価）した結果を表９に示す。

From the verification results, it was found that the length (land length) Lc of the cylindrical portion 13c is preferably about 4 mm to 5 mm.
5). About the opening angle β of the outer peripheral surface 13f of the taper portion 13b of the extrusion nipple 13 (i) The amount of occurrence of the mean at the outlet portion 17b of the flow path portion 17 of the extrusion die 12 is 360 steps from the start of extrusion to a state immediately after production. Table 9 shows the results of evaluation (evaluated in five stages from 1, 2, 3, 4 and 5 from those having a small amount of sag).

（ii）製品へのメヤニ付着数（３６０ｍ製造時）を表１０に示す。

(Ii) Table 10 shows the number of spots on the product (at the time of production of 360 m).

上記検証結果より、押出用ニップル１３のテーパ部１３ｂ外周面１３ｆの開き角度βは、１０度〜２０度が好ましいことが分かった。

From the above verification results, it was found that the opening angle β of the outer peripheral surface 13f of the tapered portion 13b of the extrusion nipple 13 is preferably 10 to 20 degrees.

  As described above, by forming the extrusion die 12 and the extrusion nipple 13 of the extrusion mold 11 as described above, it is possible to prevent the occurrence of a resin (resin residue) at the outlet portion of the extrusion mold. became. In addition, by reducing the occurrence of scraping, it is possible to form a product having no scratch on the surface of the cable, and it is possible to manufacture a stable product. Therefore, the poor product yield caused by the mains that has been generated in the past has been improved, and the cable can be manufactured at low cost.

It is sectional drawing of one Embodiment of the extrusion die structure of the electric wire concerning this invention. It is sectional drawing of the die | dye for conventional extruders.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Die for extruders 2 Outlet part 4 Hole part 5 1st curved part (R part)
6 Die entrance part 8 Second bending part (R part)
F flow path 11 Extrusion die 12 Extrusion die 12a One side (inlet side) end surface 12b The other side (outlet side) end surface 13 Extrusion nipple 13a Tip portion 13b Tapered portion 13c Cylindrical portion 13d Outlet portion 13e End surface 13f Outer peripheral surface 15 Flow Channel 16 Inlet side channel section (first channel section)
16a Inlet part 16b Inner wall surface 17 Outlet side channel part (second channel part)
17b Outlet portion α First flow passage portion inner wall surface opening angle β Taper portion opening angle D Inner diameter (outlet diameter) of flow passage portion 17
Length of Lb channel section 17 (Land length)
Lc Length of cylindrical portion 13c (land length)

Claims (2)

An extrusion die having a flow path for a thermoplastic resin member; and an extrusion nipple that is concentrically disposed in the flow path to insert and convey a wire to be covered. The wire is made of the thermoplastic resin member by extrusion molding. An extrusion mold structure of an electric wire covering
The flow path of the extrusion die has a first flow path portion that has a diameter reduced in a tapered shape from an inlet portion, and a second flow path portion having a predetermined diameter that communicates with the first flow path, and the first flow The opening angle of the passage part is set to 25 degrees to 35 degrees, the inner diameter of the second flow path part is set to 1 to 2 times the outer diameter of the product, and the length is set to 3 mm to 4 mm.
The extrusion nipple has a tapered portion that is tapered from the inlet side of the flow path and a cylindrical portion having a predetermined diameter that is connected to the tapered portion, and an opening angle of the tapered portion is 10 degrees. ~ 20 degrees, the length of the cylindrical part is set to 4 mm to 5 mm, and the outlet end face of the second flow path part of the extrusion die and the outlet part end face of the cylindrical part of the extrusion nipple are flush with each other Electric wire extrusion mold structure characterized by setting.   The extrusion mold structure for an electric wire according to claim 1, wherein the thermoplastic resin member is an olefin resin member.

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