JP2011183750A - Extruder, and molding die used for the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an extruder capable of easily bending a rubber-molded object so as to have a desired curvature, in the case of extruding a predetermined length of the bending rubber-molded object through the opening of a nozzle and bonding the end portions of the rubber molded object to form an annular member, and to provide a molding die used for the extruder. <P>SOLUTION: The extruder 1 is configured to extrude the predetermined length of the bending rubber-molded object M through the opening 41 of the nozzle 4, bond the end portions of the object M to mold the annular member. The extruder 1 includes: an extruding machine 2 for extruding rubber material R; and a molding die 3 connected with the downstream side of the extruding machine 2 in an extruding direction, and having a plurality of flow paths 5 therein in order to guide the rubber material R extruded from the extruding machine 2 toward the nozzle 4. The plurality of flow paths 5 are formed side by side in the radial direction of the rubber-molded object M, the cross-sectional area of the outer peripheral side flow path 53 for guiding the rubber material R to the curved outer peripheral part M3 of the rubber-molded object M is larger than the cross-sectional area of the inner peripheral side flow path 51 for guiding the rubber material R to the curved inner peripheral part M1. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an extrusion apparatus for extruding a curved rubber molding from a mouth opening of a base for a predetermined length and joining ends thereof to form an annular member, and a molding die used therefor. .

  Generally, when manufacturing pneumatic tires, each tire component such as inner liner, sidewall, bead, and tread is bonded together in an unvulcanized state to form a green tire, which is then vulcanized. To make it.

  The bead is composed of a bead wire serving as a reinforcing material and a bead filler made of rubber having a substantially triangular cross section. Conventionally, an annular bead filler is formed by extruding a band-shaped rubber having the above-mentioned cross-sectional shape from an extruder, cutting it into a certain length, and joining the ends thereof. However, when forming an annular member such as a bead filler, simply joining the ends of the rubber molded product extruded by the extruder so as to form an annular shape causes the peripheral portion to be The tensile stress of a direction acts, and the problem which peels in a junction part or the whole warps arises. Therefore, when a rubber material is extruded from an extruder to form an annular member, it is necessary to extrude a curved rubber molded product having a desired curvature.

  As a method of molding a curved rubber molded product using an extruder, for example, a method described in Patent Document 1 below is known. Specifically, the direction of the movable die portion of the rotary die in the extruder is rotated by an arbitrary angle with respect to the central axis in the extrusion direction of the extruder, thereby tilting the molding material from the movable die portion. Extrude to give a curved shape. The curved molded product that is pushed out in an inclined manner is placed on a turntable that rotates at the same speed as the extrusion speed in the circumferential direction directed to the movable base part, and is conveyed and guided in the arc direction. A curved molded product having a degree of curvature corresponding to the rotation angle is manufactured.

JP 2006-103262 A

  However, the method of Patent Document 1 is not preferable because it requires a mechanism for rotating and rotating the movable base part, and requires extra space and cost.

  When extruding a curved rubber molded product from the extruder, it is conceivable to increase the flow rate of the rubber material on the outer peripheral side and decrease the flow rate of the rubber material on the inner peripheral side to make the curve. However, when the cross-sectional shape of the curved rubber molding is a special shape with a thick inner periphery and a thin outer periphery, for example, a shape like a bead filler, the rubber material becomes extremely difficult to flow on the outer periphery, and the movable base part It is difficult to cope with the method of Patent Document 1 in which the direction is rotated and curved.

  Accordingly, an object of the present invention is to easily form a rubber molded product having a desired curvature when a rubber molded product curved from the opening of the base is extruded for a predetermined length and the ends thereof are joined to form an annular member. It is an object of the present invention to provide an extrusion apparatus that can be bent in such a manner, and a molding die used therefor.

In order to solve the above problems, the extrusion apparatus according to the present invention is
An extrusion apparatus for extruding a curved rubber molding from the opening of the base for a predetermined length and joining the ends together to form an annular member,
An extruder for extruding rubber material;
A molding die connected to the downstream side in the extrusion direction of the extruder and having a plurality of flow paths formed therein for guiding the rubber material extruded from the extruder to the die;
The plurality of flow paths are formed side by side in the radial direction of the rubber molded product,
A cross-sectional area of the outer peripheral flow path for guiding the rubber material to the curved outer peripheral portion of the rubber molded product is larger than a cross-sectional area of the inner peripheral flow path for guiding the rubber material to the curved inner peripheral portion. .

  The effect of the extrusion apparatus having this configuration will be described. The extrusion apparatus of the present invention feeds a rubber material extruded from an extruder to a die through a plurality of flow paths of a molding die, and extrudes a rubber molding from an opening of the die. The plurality of flow paths formed inside the molding die are formed side by side in the radial direction of the rubber molding (the radial direction of the annular member to be molded), and the cross-sectional area of the outer peripheral side flow path is the inner peripheral side It is larger than the cross-sectional area of the flow path. When the cross-sectional area of the flow path is increased, the rubber pressure applied to the flow path is reduced, so that the rubber flow rate of the rubber material is increased. As a result, the outer peripheral flow path having a larger cross-sectional area than the inner peripheral flow path has a larger rubber flow rate than the inner peripheral flow path, and as a result, the extrusion amount of the rubber molding extruded from the opening of the base is Since the curved outer peripheral portion is larger than the curved inner peripheral portion, it is possible to easily extrude a curved rubber molded product. Moreover, it is also easy to curve the rubber molding so as to have a desired curvature by appropriately adjusting the cross-sectional areas of the inner peripheral flow path and the outer peripheral flow path.

  In the extrusion apparatus according to the present invention, it is preferable that the cross-sectional area of the outer peripheral flow path is larger than the cross-sectional area of the inner peripheral flow path at least on the upstream side in the extrusion direction.

  In order to reduce the rubber pressure applied to the flow path, it is effective to increase the cross-sectional area of the flow path on the upstream side in the extrusion direction connected to the extruder. It is possible to reliably increase the rubber flow rate as compared with the inner peripheral flow path.

  In the extrusion apparatus according to the present invention, it is preferable that the molding die includes a separable die body and a nest accommodated in the die body and having the flow path formed therein.

  According to this configuration, by preparing a plurality of nestings that can bend the rubber molding so as to have an arbitrary curvature, the rubber molding that is curved so as to have a desired curvature simply by replacing the nesting. Can be extruded.

  In the extrusion apparatus of the present invention, it is preferable that the annular member is an annular bead filler having a substantially triangular cross section that is vertically long in the radial direction.

  In order to extrude a bead filler having a substantially triangular cross-section that is vertically long in the radial direction, the opening of the die needs to have a substantially triangular shape that is vertically long in the radial direction corresponding to the bead filler. In such an opening shape, since the outer peripheral side is thin, the rubber material is very difficult to flow. Therefore, the present invention is particularly useful when a bead filler is molded as an annular member.

1 shows the overall configuration of the extrusion apparatus of the present invention, (a) is a perspective view, (b) is a longitudinal sectional view. Exploded perspective view of molding die and die Nested cross section Cross-sectional view showing another embodiment of nesting Cross-sectional view showing another embodiment of nesting

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows the overall configuration of an extrusion apparatus according to the present invention, where (a) is a perspective view and (b) is a longitudinal sectional view. The arrow X in the figure indicates the extrusion direction.

  As shown in the figure, an extrusion apparatus 1 according to the present invention includes an extruder 2, a molding die 3, and a die 4. The extrusion device 1 of the present invention is for extruding a curved rubber molding M from an opening 41 of a base 4 for a predetermined length, and joining ends thereof to form an annular member.

  The extruder 2 can knead the rubber material R supplied from a hopper (not shown) inside and extrude it from the extruder tip 2a. As the extruder 2, any conventionally known extruder can be used.

  The molding die 3 is connected to the downstream side in the extrusion direction X of the extruder 2, that is, to the extruder tip 2a. The molding die 3 is formed with a plurality of flow paths 5 for guiding the rubber material R extruded from the extruder 2 to the die 4 (details will be described later).

  The base 4 is connected to the downstream side in the extrusion direction X of the molding die 3. The base 4 is provided with a through hole along the extrusion direction X, and the rubber material R guided to the base 4 by the molding die 3 is pushed out from the opening 41 on the downstream side. The opening 41 is formed in a shape corresponding to the cross-sectional shape of the rubber molded product M to be extruded. In the present embodiment, the opening 41 has a rectangular shape. The opening on the upstream side of the through hole is also rectangular.

  FIG. 2 is an exploded perspective view of the molding die 3 and the base 4. The molding die 3 includes a mold body 31 that can be divided and a nest 32 that is accommodated in the mold body 31. As a whole, the rectangular parallelepiped mold body 31 includes an upper mold 311 and a lower mold 312. The upper mold 311 and the lower mold 312 are formed with concave grooves 311a and 312a along the extrusion direction X, respectively, on opposite surfaces. Furthermore, fitting holes 311b and 312b are provided in the center of the concave grooves 311a and 312a, respectively. The mold body 31 may include a temperature adjustment mechanism for heating the rubber material R in the flow path.

  The nest 32 includes a rectangular parallelepiped channel portion 32a and convex portions 32b and 32c that protrude from the channel portion 32a in the vertical direction. The flow path portion 32 a is configured to fit into the concave grooves 311 a and 312 a of the molding die 3, and the convex portions 32 b and 32 c are configured to fit into the fitting holes 311 b and 312 b of the molding die 3, respectively. ing.

  A plurality of flow paths 5 are formed in the flow path portion 32a. In the present embodiment, an example in which three flow paths 51, 52, 53 are formed is shown, and the three flow paths are collectively referred to as a flow path 5. FIG. 3 shows a cross-sectional view of the nesting 32 of FIG. All of the flow paths 5 are through holes formed along the extrusion direction X. In this embodiment, as shown in FIG. 2, the cross section of any flow path is circular. The cross section of the flow path is not limited to a circular shape and may be a square shape or the like, but a circular shape is preferable from the viewpoint of processability, rubber fluidity, and the like.

  The three flow paths 51, 52, 53 are arranged side by side in the radial direction of the curved rubber molded product M, that is, in the radial direction of the annular member to be molded. Here, the inner peripheral flow path 51, the central flow path 52, and the outer peripheral flow path 53 are formed on the curved inner peripheral part M1, the central part M2, and the curved outer peripheral part M3 of the curved rubber molded product M shown in FIG. Each corresponding rubber material R is guided to the base 4.

  On the downstream side in the extrusion direction X, the inner diameter D1 of the inner peripheral flow path 51, the inner diameter D2 of the central flow path 52, and the inner diameter D3 of the outer peripheral flow path 53 are all the same size. Further, on the upstream side in the extrusion direction X, the inner diameter D4 of the inner circumferential flow path 51 is the same size as the inner diameter D1 on the downstream side. On the other hand, the inner diameter D5 on the upstream side of the central channel 52 and the inner diameter D6 on the upstream side of the outer channel 53 are larger than the inner diameters D2 and D3 on the downstream side from the upstream side to the predetermined lengths L1 and L2. The diameter has been expanded. Thus, when the inner diameter of the flow path 5 is increased and the cross-sectional area is increased, the rubber pressure applied to the flow path 5 is reduced, and the rubber flow rate of the rubber material R is increased. As a result, the rubber flow rate flowing through the central channel 52 and the outer peripheral channel 53 is greater than the rubber flow rate flowing through the inner peripheral channel 51.

  Further, in this example, the inner diameter D5 and the inner diameter D6 are equal, and the length L2 from the upstream side in the outer peripheral flow path 53 is longer than the length L1 from the upstream side in the central flow path 52. As a result, the volume of the enlarged diameter portion of the outer peripheral flow path 53 is larger than the volume of the enlarged diameter portion of the central flow path 52, and the rubber flow rate flowing through the outer peripheral flow path 53 flows through the central flow path 52. It becomes larger than the rubber flow rate.

  As a result, by forming the flow channel 5 as shown in FIG. 3, the rubber flow rate flowing through the flow channel 5 increases in the order of the inner peripheral side, the central portion, and the outer peripheral side, and is pushed out from the opening 41 of the base 4. The molded rubber product M has a curved shape as shown in FIG.

  When it is desired to further increase the curvature of the curved rubber molded product M, the lengths L1 and L2 are appropriately made longer than those in FIG. 3 as shown in FIG. Increase the rubber flow rate.

  Further, when it is desired to further increase the curvature of the curved rubber molded product M, the inner diameter D5 of the central channel 52 and the inner diameter D6 of the outer peripheral channel 53 on the upstream side may be further increased. For example, when the bead filler is formed by making the opening 41 of the base 4 into a substantially triangular shape that is vertically long in the radial direction, L1 and L1 in the central channel 52 and the outer circumferential channel 53 as shown in FIG. The rubber flow rate can be adjusted by increasing L2 or increasing the inner diameter D5 and the inner diameter D6. In this example, D4 <D5 <D6.

<Other embodiments>
The annular member may be an annular member such as a sidewall in addition to the above bead filler.

  In the above embodiment, the flow path 5 has an inner diameter that is increased from the upstream side to the predetermined lengths L1 and L2 as shown in FIG. 3, but may have a constant inner diameter from the upstream side to the downstream side. That is, the relationship between the inner diameters may be D1 = D4 <D2 = D5 <D3 = D6.

  In the above embodiment, the number of the flow paths 5 is three, but the number of the flow paths 5 may be two, or may be four or more.

DESCRIPTION OF SYMBOLS 1 Extruder 2 Extruder 3 Mold 4 Die 5 Flow path 31 Mold body 32 Nest 41 Opening 51 Inner peripheral flow path 52 Central flow path 53 Outer peripheral flow path R Rubber material M Rubber molding M1 Curve Inner circumference M3 Curved outer circumference

Claims (5)

An extrusion apparatus for extruding a curved rubber molding from the opening of the base for a predetermined length and joining the ends together to form an annular member,
An extruder for extruding rubber material;
A molding die connected to the downstream side in the extrusion direction of the extruder and having a plurality of flow paths formed therein for guiding the rubber material extruded from the extruder to the die;
The plurality of flow paths are formed side by side in the radial direction of the rubber molded product,
An extrusion apparatus characterized in that a cross-sectional area of an outer peripheral side channel for guiding a rubber material to the curved outer peripheral part of the rubber molding is larger than a cross-sectional area of an inner peripheral side channel for guiding the rubber material to a curved inner peripheral part.   The extrusion apparatus according to claim 1, wherein a cross-sectional area of the outer peripheral flow path is larger than a cross-sectional area of the inner peripheral flow path at least on the upstream side in the extrusion direction.   The extrusion apparatus according to claim 1 or 2, wherein the molding die includes a mold body that can be divided and a nest that is housed in the mold body and in which the flow path is formed. .   The extrusion apparatus according to any one of claims 1 to 3, wherein the annular member is an annular bead filler having a substantially triangular cross section that is vertically long in a radial direction.   The molding die used for the extrusion apparatus of any one of Claims 1-4.

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