JP2018034315A - Nozzle for extruder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a nozzle for an extruder, when a sheet-shaped rubber member is extrusion-molded, capable of sufficiently suppressing the generation of the edge cutting of the extrusion-molded rubber member.SOLUTION: Provided is a nozzle for an extruder extrusion-molding a tire composing member with a prescribed cross-sectional shape, and comprising: a feed port to be fed with a material rubber; a discharge port with a shape same as that of the cross-sectional shape; and a rubber flow passage passing from the feed port to the discharge port. The rubber flow passage is respectively formed with rubber reservoirs each having a triangular tilted face from the feed port side toward the discharge port side on both the sides, and each triangular tilted face is formed so as to be tapered from the feed port side toward the discharge port side and is further formed so as to be tilted to the outside to the edge of the discharge port from the feed port side toward the discharge port side.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a die for an extruder for extruding a material rubber into a tire constituent member having a predetermined cross-sectional shape.

  In the production process of a green tire, for example, a sheet-like rubber member such as an inner liner rubber, a carcass ply, a sidewall rubber, a clinch rubber, or a tread rubber is attached to a molding drum to form a cylindrical green tire.

  These sheet-like rubber members are extruded into a sheet shape with a predetermined cross-sectional shape by an extruder (see, for example, Patent Document 1).

  The extruder includes an extruder die at the tip of the extruder body. Also, a jig (preformer) just before the base is provided adjacent to the upstream side of the base for the normal extruder, and the material rubber sent by the screw is used for the rubber flow path formed in the preformer and the extruder. It is formed in a predetermined shape by being discharged from the discharge port through the rubber flow path formed in the base (see, for example, Patent Document 2).

  When molding using the above extruder, the edge part of the rubber flow path of the die for the extruder is difficult for the material rubber to flow, and when the discharged rubber sheet is broken or cut to a predetermined length There is a problem of shrinking. In order to solve such problems, for example, an extruder die having a die plate 21 processed on the supply port side as shown in FIGS. 7 and 8 is used. 7 is an enlarged plan view of a conventional die plate as viewed from below, and FIG. 8 is a plan view of the conventional die plate as viewed from below.

  The conventional die plate 21 is provided with a rubber reservoir 23 so that the material rubber can be taken in from the outside of the edge toward the edge portion 22 of the rubber flow path 24. By using the extruder die processed in this way, the discharge amount in the vicinity of the edge portion 22 increases, so that the occurrence of edge breakage and shrinkage is suppressed.

JP 2002-160281 A JP 2012-81716 A

  However, when the above-described die plate is used, the occurrence of shrinkage can be eliminated. However, since the material rubber flows inward from the outer side in the width direction toward the edge in the edge portion 22, the material rubber is discharged from the edge portion 22. The increase in quantity is not enough. For this reason, there has been a problem that the occurrence of edge breakage cannot be sufficiently suppressed.

  Then, this invention makes it a subject to provide the nozzle | cap | die for extruders which can fully suppress generation | occurrence | production of the edge piece of the extruded rubber member when extruding a sheet-like rubber member.

The invention described in claim 1
An extruder die for extruding a tire component having a predetermined cross-sectional shape,
A supply port to which material rubber is supplied;
A discharge port having the same shape as the cross-sectional shape;
A rubber flow path leading from the supply port to the discharge port,
In the rubber flow path, rubber reservoirs each having a triangular inclined surface from the supply port side toward the discharge port side are formed on both sides, respectively.
Each inclined surface of the triangle is tapered from the supply port side toward the discharge port side, and further, from the supply port side toward the discharge port side with respect to the edge of the discharge port It is a die for an extruder characterized by being inclined outward.

The invention described in claim 2
The position of the apex closest to the discharge port of the inclined surface of the triangle is substantially coincident with the position of the discharge port,
2. The extruder die according to claim 1, wherein a position of an apex closest to the supply port of the triangular inclined surface substantially coincides with a position of the supply port.

The invention according to claim 3
3. The extruder die according to claim 1, wherein a width of the rubber reservoir having the triangular inclined surface at the supply port is 10 to 20 mm. 4.

The invention according to claim 4
The vertical distance between the apex closest to the supply port and the apex closest to the supply port next to the inclined surface of the triangle is 10 to 15 mm. It is a die for an extruder described in 1.

  ADVANTAGE OF THE INVENTION According to this invention, when extruding a sheet-like rubber member, the nozzle | cap | die for extruders which can fully suppress generation | occurrence | production of the edge cut of the extruded rubber member can be provided.

It is a front view by the side of the supply port of the nozzle | cap | die for extruders which concerns on one embodiment of this invention. It is the top view which looked at the die plate in one embodiment of the present invention from the lower part. It is the perspective view which combined the nozzle | cap | die for extruders which concerns on one embodiment of this invention, and the preformer. It is a figure explaining the material rubber flow in the edge part of the nozzle | cap | die for extruders which concerns on one embodiment of this invention. It is a YY arrow line view of the nozzle | cap | die for extruders which concerns on one embodiment of this invention. It is the front view which looked at the preformer from the discharge outlet side. It is the enlarged plan view which looked at the conventional die plate from the lower part. It is the top view which looked at the conventional die plate from the bottom.

  Hereinafter, the present invention will be described with reference to the drawings by embodiments.

1. Extruder Base FIG. 1 is a front view on the supply port side of an extruder base according to the present embodiment. In FIG. 1, the die plate 11 which is characteristic in the present invention is indicated by a solid line, and the receiver 12 is indicated by a two-dot chain line. FIG. 2 is a plan view of the die plate 11 viewed from the X direction of FIG. FIG. 3 is a perspective view in which the extruder die and the preformer according to the present embodiment are combined.

  As shown in FIG. 1, the base 1 includes a die plate 11 and a receiver 12. The base 1 includes a supply port 14 to which the material rubber is supplied, a discharge port 16 having the same shape as the tire constituent member, and a rubber flow path 15 that leads from the supply port 14 to the discharge port 16. The rubber flow path 15 is formed with rubber reservoirs each having a triangular inclined surface 13 from the supply port 14 toward the discharge port 16 on both sides.

  Each triangular inclined surface 13 is tapered from the supply port 14 side toward the discharge port 16 side, and further, from the supply port 14 side toward the discharge port 16 side with respect to the edge of the discharge port 16. Inclined outward.

  As shown in FIG. 2, A is the apex closest to the supply port 14 among the apexes of the triangular inclined surface 13, A ′ is the apex next to the supply port 14, and B is the closest to the discharge port 16. Close vertex.

  C is the width at the supply port 14 of the rubber reservoir having the triangular inclined surface 13. D is the vertical distance between the apex B and the apex A ′ of the triangular inclined surface 13, and is the height of the supply port.

  FIG. 4 is a diagram for explaining the flow of the material rubber at the edge portion of the extruder die according to the present embodiment, and FIG. 5 is a view taken along the YY arrow of the extruder die according to the present embodiment. is there. In FIG. 5, 17 is a supply port forming end surface, 18 is a discharge port forming end surface, and t is the thickness of the base.

  By providing the rubber reservoir having the triangular inclined surface 13 as described above, when the material rubber moves from the supply port 14 to the discharge port 16 as shown by arrows in FIG. Can be forced to flow from the inside toward the outside with respect to the edge of the discharge port 16 in the width direction. Further, as shown in FIG. 5, the material rubber flows downwardly from the vertex A ′ toward the vertex B. As a result, the flow of the material rubber is concentrated on the edge of the rubber flow path 15 near the discharge port 16, and the occurrence of edge breakage of the extruded rubber member can be sufficiently suppressed.

2. Method of Using Extruder Base The above-described base 1 is used in combination with the following preformer. That is, as shown in FIG. 3, the base 1 is attached to the discharge port side end face of the preformer 3 on the downstream side of the preformer 3. The material rubber is supplied to the rubber flow path 15 of the base 1 through the preformer 3, and tire constituent members having a predetermined cross-sectional shape are continuously discharged from the discharge port 16. The preformer 3 includes an upper mold 31 and a lower mold 32. For example, as shown in FIG. 6, a discharge port 33 having a rectangular cross section is formed.

3. Preferred Mode of Extruder Base The width C (FIG. 1) at the supply port 14 of the rubber reservoir having the triangular inclined surface 13 is preferably 10 to 20 mm.

  When the width C is within this range, the effect of forming the triangular inclined surface 13 is more fully exhibited, and thus edge breakage is sufficiently suppressed.

  In addition, the vertical distance D (the height of the supply port) D between the apex B and the apex A ′ of the triangular inclined surface 13 is set to be equal to or greater than the height E (FIG. 6) of the discharge port 33 of the preformer 3. It is preferable that the width of 14 (the frontage) be equal to or larger than the width of the discharge port 33 because the retention of the material rubber at the boundary between the base 1 and the preformer 3 is suppressed and the material rubber flows more smoothly. FIG. 6 is a front view of the preformer as seen from the discharge port side.

  Hereinafter, based on an Example, this invention is demonstrated more concretely. In the following, the side wall rubber of a tire of size 195 / 65R15 was continuously extruded 20 m at an extrusion rotation speed of 30.0 rpm. The height of the discharge port of the preformer (E in FIG. 6) was set to 10 mm.

1. Extrusion molding of rubber member (1) Examples 1 to 15
1, 2, and 5, the width C of the rubber reservoir and the height D of the supply port are shown in Table 1 on the triangular inclined surface 13 of the vertex A, the vertex A ′, and the vertex B. Extrusion processing was performed using an extruder die changed as shown in FIG.

(2) Comparative Example 1
Extrusion was performed using an extruder die having the same shape on the supply port side as that on the discharge port side.

(3) Comparative Example 2
Extrusion was performed using an extruder die formed with a rubber reservoir (width a: 5 mm, length b: 11 mm, distance c from edge portion: 10 mm) shown in FIG.

2. Evaluation method The presence or absence of edge breakage was visually inspected, and an evaluation was made based on the number of occurrences of edge breakage by a 5-point method. 4 points or more are particularly preferable. The evaluation results are summarized in Table 1.

  From Table 1, the shape on the supply port side is the same as the shape on the discharge port side, and in the case of Comparative Example 1 in which no measures are taken for increasing the discharge amount in the vicinity of the edge portion, the evaluation score was 1 point. On the other hand, in Comparative Example 2 in which the base provided with the rubber reservoir 23 shown in FIG. 7 is used, the evaluation score is improved to 2 points. However, even if the rubber reservoir 23 is provided, it does not reach the particularly preferable four points, and it cannot be said that the effect of suppressing edge breakage is sufficient.

  On the other hand, the triangle has an apex A of the triangular inclined surface 13 defined by the extruder die of the present embodiment, and the thickness is reduced from the apex A toward the predetermined apex B where the thickness is the thinnest. In Examples 1 to 15 using the base on which the inclined surface 13 is formed, all of the evaluation points are equal to or higher than those of Comparative Example 2, and it can be seen that there is an effect for suppressing edge breakage.

  Also, in the examples, when the width C of the rubber pool is 10 to 20 mm and the height D of the supply port is 10 to 15 mm (Examples 5, 6, 8, 9, 11, 12), the evaluation points Was 4 points or more, and it was found that a particularly remarkable effect was obtained.

  As mentioned above, although this invention was demonstrated based on embodiment, this invention is not limited to said embodiment. Various modifications can be made to the above-described embodiment within the same and equivalent scope as the present invention.

1 base (extruder base)
DESCRIPTION OF SYMBOLS 3 Preformer 11, 21 Die plate 12 Receptacle 13 Triangular inclined surface 16, 33 Discharge port 14 Supply port 15, 24 Rubber flow path 17 Supply port formation end surface 18 Discharge port formation end surface 22 Edge part 23 Rubber reservoir 31 Upper mold | type 32 Lower mold A, A ', B Apex a, C Rubber reservoir width b Rubber reservoir length c Distance from edge D Supply port height E Discharge port height t Base thickness

Claims (4)

An extruder die for extruding a tire component having a predetermined cross-sectional shape,
A supply port to which material rubber is supplied;
A discharge port having the same shape as the cross-sectional shape;
A rubber flow path leading from the supply port to the discharge port,
In the rubber flow path, rubber reservoirs each having a triangular inclined surface from the supply port side toward the discharge port side are formed on both sides, respectively.
Each inclined surface of the triangle is tapered from the supply port side toward the discharge port side, and further, from the supply port side toward the discharge port side with respect to the edge of the discharge port A die for an extruder, which is formed to be inclined outward. The position of the apex closest to the discharge port of the inclined surface of the triangle is substantially coincident with the position of the discharge port,
2. The extruder die according to claim 1, wherein a position of an apex closest to the supply port of the triangular inclined surface substantially coincides with a position of the supply port.   The die for an extruder according to claim 1 or 2, wherein a width of the supply port of the rubber reservoir having the triangular inclined surface is 10 to 20 mm.   The vertical distance between the apex closest to the supply port and the apex closest to the supply port next to the inclined surface of the triangle is 10 to 15 mm. A base for an extruder according to 1.

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