JP2001096601A - Extruding die for cylindrical body composed of rubber, resin, etc. - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the generation of a groove-shaped thin part (spider mark) in a cylindrical body composed of rubber, resin, etc., in which rubber, resin, etc. are packed insufficiently, on the spider downstream side of an extruding die for the cylindrical body. SOLUTION: In a spider 8 fitted to an extruding die 10, an outer peripheral side opening part 14 and a central side opening part 15 are formed continually between a spider outer cylinder 12 and a mandrel 6 to be arranged in the shape of concentric layers, and in each fan-shape, connecting both ends of each standard length (x) which divided the outer circumference of the spider 8 uniformly with the center (c) of the spider 8, the areas of the openings are equalized in each fan-shape.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an extrusion die used for extruding a cylindrical body made of rubber, resin or the like, in which a spider having no spider mark is provided between an expansion region and a compression region. It relates to the extrusion die provided.

[0002]

2. Description of the Related Art FIG. 5 is a longitudinal sectional view of a general extrusion die of a conventional extruder for a cylindrical body such as a rubber or a resin. As shown in FIG. (The whole is not shown), that is, the screen 3 and the breaker plate 4 are attached to the tip 40 of the barrel 1 having the screw 2 therein. Furthermore, the extrusion die 1
Reference numeral 0 denotes an expansion region 7, a spider 8, a compression region 9, and a mandrel 36 supported by the spider member 5 therein.
It has.

[0003] Rubber, resin and the like formed into a cylindrical body are heated and kneaded by an extruder kneading portion (not shown) to be in a fluid state. The rubber, resin and the like are removed of foreign matter by the filter 3, fed into the extrusion die 10, formed into a cylindrical shape by the expansion region 7 and the mandrel 36, and after passing through the spider 8, are compressed by the compression region 9. It is extruded as a cylindrical body from the nozzle 11 while repairing a defect (a spider mark, which will be described in detail later) due to the spider member 5.

A conventional extrusion die spider 8 is shown in FIG.
As shown in the front view of FIG.
A cross-shaped spider member 5 is provided inside the spider outer cylinder 12 that is in contact with 5 (see FIG. 5) to integrally support the mandrel support 6. In this case, the mandrel support 6 is tubular and fits and supports a mandrel 31 (see FIG. 8), which will be described in detail later, inside. An opening 13 is formed in the spider member 5 to serve as a flow path for rubber, resin, or the like. FIG. 4 shows another shape of the spider member 5.
As shown in part (b), the spider member 5 'is formed in a spiral shape, and as shown in FIG. 3, there is a spider member 5' provided with two or three circular openings.

However, in the conventional extrusion die as described above, the spider member 5 for supporting the mandrel 36 inside the extrusion die 10 is formed in the expansion region 7 and flows. It is attached by penetrating a cylindrical body such as rubber or resin. Therefore, this cylindrical body is cut once in the flow direction at the position of the spider member 5, compressed by the subsequent compression region 9, and formed again into a cylindrical body. At this time, there is a problem that a portion which is cut by the spider member 5 and has a gap is not sufficiently repaired by the compression region 9 and a groove-like defect occurs in the flow direction. This groove-like defect is what is called a spider mark.

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and has as its object to provide an extrusion die for a cylindrical body made of rubber, resin, or the like, the extrusion die having a spider free from spider marks. It is an object.

[0006]

In order to solve the above problems, a die for extruding a cylindrical body made of rubber, resin or the like according to claim 1 (hereinafter also referred to as a rubber or resin cylindrical body) is provided. An extrusion die provided with a spider between the expansion region and the compression region, wherein the spider is disk-shaped, forms a spider outer cylinder on the outer peripheral side, and has a mandrel support body that supports the mandrel inside thereof. Supported via a spider member,
The spider member is provided with an opening that is a flow path of the rubber, resin, or the like, and the opening is formed intermittently in a plurality of layers concentrically, and both ends of a reference length obtained by equally dividing the outer periphery of the spider. Assuming a sector connecting the center point of the spider and the center of the spider, the area of the opening in the sector is equal in any sector.

By providing a plurality of concentric circular openings between the spider members, an outer peripheral opening (referred to as an outer peripheral opening of the plural layers of openings) and a central opening (multiple layers) are provided. A support member continuous in the outer peripheral direction is formed between the spider outer cylinder and the cylindrical member. A radial support member connecting the mandrel support is formed (there is a spider member integrally with these support members). In addition, since the openings are provided in a plurality of layers concentrically, the outer peripheral openings and the central openings can be provided alternately and partially overlap in the radial direction depending on the shape. This makes it possible to adjust the radial opening ratio, which will be described in detail later, and to uniformly adjust the amount of rubber, resin, and the like passing through these openings over the entire circumference.

[0008] The spider is formed in a disk shape for extruding a cylindrical body. Assuming a reference length by equally dividing the outer periphery of this spider, and assuming a sector connecting both ends of each reference length and the center of the spider, the opening area in the sector is equal in any sector. Designed to be. That is, the area of the opening is equal in any sector shape in the circumferential direction of the spider, and the thickness of rubber, resin, or the like extruded from the opening is equal in any position in the outer circumferential direction. That is, spider marks can be prevented from being generated.

In the present specification, the sector assumed as described above is also referred to as a reference sector, and the value obtained by dividing the area of the opening formed in the reference sector by the area of the reference sector is defined in the radial direction. Also called aperture ratio.

[0010] The extrusion die for a cylindrical body made of rubber, resin, or the like according to the second aspect, has a disk-shaped spider, forms a spider outer cylinder on the outer peripheral side, and supports a mandrel inside the spider outer cylinder. The body is supported via a spider member, and the spider member is provided with an opening serving as a flow path for the rubber or resin, and the opening is formed intermittently in a plurality of layers of concentric circles. Assuming a sector shape in which (360 °) is equally divided, the area of the opening is equal in any sector shape.

In the first aspect of the present invention, instead of dividing the disk-shaped spider into sectors according to the reference length, the center angle (360 °) is equally divided into sectors. By making the areas of the openings equal in any of the fan shapes, the thickness of the extruded cylindrical body such as rubber becomes uniform at any position in the outer peripheral direction.

In a third aspect of the present invention, a cylindrical die made of rubber, resin, or the like has a sector shape in which the openings are provided in two layers: an outer peripheral opening and a central opening. The extension lines of the both sides intersect at the center point of the spider, the extension lines of the sides of the outer peripheral opening coincide with the sides of the central opening, and the outer peripheral opening and the central opening are They are provided alternately in the outer peripheral direction.

Since the extension of the side of the outer peripheral side opening and the side of the central side opening coincide, the outer peripheral side opening and the central side opening do not overlap in the radial direction and are not separated in the outer peripheral direction. Become. The cylindrical body extruded from these openings,
There are no overlapping or spaced parts, and no spider marks are generated.

According to a fourth aspect of the present invention, in the extrusion die for a cylindrical body made of rubber, resin, or the like, the opening has a sector shape provided in two layers, an outer peripheral opening and a central opening. The radial length of the outer peripheral opening is shorter than the radial length of the central opening. Since the outer peripheral side length of the outer peripheral side opening in the reference sector is longer than the outer peripheral side length of the center side opening,
In order to equalize the opening area (radial opening ratio) in the reference sector, it is necessary to make the radial length of the outer peripheral opening shorter than the radial length of the central opening.

According to a fifth aspect of the present invention, in the extrusion die for a cylindrical body made of rubber, resin, or the like, the openings are alternately formed in two layers of an outer peripheral opening and a central opening and in the outer peripheral direction of the spider. The extension lines of both sides intersect at the center point of the spider, and the intersection angle is an angle obtained by equally dividing the center angle of the spider according to the number of the openings. is there.

The extension lines on both sides of the opening intersect at the center point, and the intersection angle is determined by the number of openings (total number of two layers).
Is an angle obtained by equally dividing the center angle of the spider in accordance with. As a result, the outer peripheral side opening and the central side opening are evenly distributed around the spider.

According to a sixth aspect of the present invention, the extrusion die for a cylindrical body made of rubber, resin, or the like is assumed to have a fan shape connecting both ends of a reference length obtained by equally dividing the outer periphery of the spider and a center point of the spider. At this time, the difference between the maximum value and the minimum value of a value obtained by dividing the area of the opening in the sector by the area of each sector (referred to as radial opening ratio) is divided by the maximum value (the radial opening ratio). (Also referred to as variation) is less than 0.45.

It is desirable that the radial aperture ratio is uniform, but the variation in the radial aperture ratio is 0.45, that is, the difference between the maximum value and the minimum value of the radial aperture ratio is 4 which is the maximum value.
If it is less than 5%, the extruded cylindrical body does not show spider marks that are problematic in quality.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, an embodiment of a cylindrical body extrusion die according to the present invention will be described with reference to the drawings.

FIG. 1 is a front view and a sectional view showing a spider 8 according to the first embodiment, FIG. 2 is a front view showing a spider 8 'according to the second embodiment, and FIG. 3 is a spider 8 "according to the third embodiment.
FIG.

Embodiment 1 As shown in the front view of the spider 8 in FIG. 1A, the openings (the outer opening 14 and the center opening 14) which are evenly arranged in two layers in the outer direction of the spider 8 are shown. 15) are fan-shaped, and are arranged alternately so as not to overlap in the radial direction.

The outer peripheral side opening portion 14 and the central side opening portion 15 have an outer peripheral length between both ends (segment 17) of a predetermined length x obtained by dividing the outer periphery of the spider 8 into 12 equal parts and the center point c of the spider 8. Lengths y and z divided by the connected radius display line 16 are set. The sides of the openings 14 and 15 coincide with the radius display line 16, and the sides of the outer peripheral side opening 14 and the sides of the center side opening 15 are arranged on the same radius display line 16. ing. Due to this positional relationship, the outer peripheral side opening 14 and the central side opening 15 are in a positional relationship such that they do not overlap in the radial direction and do not separate in the outer peripheral direction.

The radial length a of the outer peripheral side opening 14 is designed to be shorter than the radial length b of the central side opening 15,
a: b is derived by determining the cross-sectional area of each opening to be equal. As a result, the ratio of the area of the opening to the area of the sector corresponding to the reference length (the length obtained by dividing the entire circumference of the spider into 30 in the first embodiment, which will be described later in detail) (radial opening ratio) is constant. The spider outer cylinder 12 and the mandrel support 6 are provided between the layer of the outer peripheral side opening 14 and the layer of the central side opening 15 which are arranged concentrically.
D that can form a spider member 5 sufficient to connect
Is open.

By forming the outer peripheral side opening 14 and the central side opening 15, the radial opening ratio becomes uniform over the entire circumference of the spider 8, and the cylindrical body made of extruded rubber, resin, or the like. Becomes uniform.

FIG. 1B is a cross-sectional view taken along line AA of FIG. 1A. The spider 8 has an outer peripheral opening 14 at the center of the spider outer cylinder 12 and a center as shown in FIG. Side opening 15
Are formed, and a cylindrical mandrel support portion 6 is provided on the center side thereof. A mandrel 31 shown in a longitudinal sectional view in FIG. 8 is fitted into the hollow portion of the mandrel support portion 6, and a mandrel tip portion 30 is attached to a coupling portion 32 of the mandrel 31. To form an extrusion die. Note that the imaginary line in FIG. 8 indicates a state in which the spider 8 is fitted to the mandrel 31, and the flow direction of rubber, resin, or the like is indicated by an arrow x '.

Embodiment 2 As shown in FIG. 2, the shapes of the openings 14 'and 15' of the spider 8 'of the extrusion die of Embodiment 2 are triangular, and one vertex is formed on the outer peripheral side layer. An outer layer side opening 14 ′ having a triangular shape toward the center direction, and a center side opening 15 ′ having a triangular shape with one vertex directed toward the outer periphery of the spider in the center side layer, are alternately arranged. They are arranged close to each other.

One of the vertexes of the center side opening 15 'is arranged close to the gap between the intermittently arranged outer side openings 14'. This allows the mandrel support 6 '
Can be designed to be thin, and the aperture ratio of the entire spider 8 'can be designed to be large. Further, by designing the circumferential ends 18 of the openings 14 ′ and 15 ′ to be acute angles, the radial opening ratio of the sector 19 with respect to the reference length can be made more uniform.

On the other hand, if the circumferential end portion 18 is formed at an acute angle, it becomes difficult to remove the rubber, resin, etc. (also referred to as residual rubber) remaining without being extruded at the end of the extrusion operation.
Processing of the spider 8 becomes difficult. Therefore, in the second embodiment,
By forming the circumferential ends 18 of the openings 14 ′ and 15 ′ in a semicircular shape, processing of residual rubber and the like is facilitated, and processing of the spider is facilitated. Although there is some variation in the radial direction aperture ratio, it can be significantly reduced as compared with the comparative example.

Incidentally, the reference length for calculating the radial opening ratio is such that the outer periphery of the spider 8 'is set to the outer peripheral side opening 14'.
Center opening 15 'adjacent to the radius passing through the center corner of
And the radius passing through the outer corner of the outer periphery is divided into five equal parts (
Each length shown by).

COMPARATIVE EXAMPLE 1 As shown in FIG. 3, the extrusion die spider 8 "of Comparative Example 1 has openings 14" and 15 "having a circular cross-sectional shape, and the outer peripheral opening 14" is located on the center side. It is a larger circle than the opening 15 ″. The intermittent opening 1 provided in two layers
By making the cross-sectional shape of 4 "and 15" circular, processing of the spider 8 "becomes extremely simple and adhesion of residual rubber and the like is reduced. In addition, the openings 14" and 15 "partially overlap in the radial direction. The reference sector for calculating the radial opening ratio is formed by connecting the outer periphery of the spider 8 ″ to the outer peripheral opening 14 ″.
And the other outer peripheral side opening 14 ″
Equally divides by 8 with the radius passing through the center of the standard length (~)
Was set as a fan shape.

COMPARATIVE EXAMPLE 2 As shown in FIG. 4A, a spider 8 of Comparative Example 2 has a cross-shaped spider member 5 provided inside a spider outer cylinder 12 to support a mandrel support 6, and a spider member 5, an opening 13 is formed. Note that the reference length for calculating the radial opening ratio is 16
It is equally divided into (~ 16).

The variation in the aperture ratio in the radial direction between Examples 1 and 2 and Comparative Examples 1 and 2 is as follows.

FIG. 6A shows Example 1, FIG. 6B shows Example 2, FIG. 6C shows Comparative Example 1, and FIG. 7 shows Comparative Example 2.
The numbers on the vertical axis represent numerical numbers of the radial opening ratios (referred to as opening indices), and represent the reference sector numbers (also referred to as sector numbers) divided by reference lengths (, etc.) or the positions of the outer circumferences. The position numbers (in the case of Comparative Example 2) are shown on the horizontal axis. The variation of the index in each figure represents the variation of the radial aperture ratio. Note that the radial aperture ratio is based on a reference sector (see FIG. 1) that connects both ends of each reference length x obtained by equally dividing the outer circumference of the spiders 8, 8 ′, 8 ″ and the spider center point c. It is calculated by dividing the area of the openings 13, 14, 15 and the like occupied in each sector by the area of the whole sector. The thickness variation of the cylindrical body becomes small.

FIG. 6A shows the opening indices of the first embodiment in the order of sector numbers in which a set of the outer opening 14 and the center opening 15 are divided into five (see FIG. 1A). it's shown. The aperture index is stable at approximately 20 regardless of the sector number, indicating that the radial aperture ratio is constant. FIG. 6B shows the opening indices of Example 2 in the order of the sector numbers. The opening indices vary from approximately 17 to 25, and the variation in the radial aperture ratio is 32%. FIG. 6C shows the opening indices of Comparative Example 1 in the order of the sector numbers, and the opening indices vary from 5 to 9;
The variation in the radial aperture ratio is 45%. In Comparative Example 1, a small amount of spider marks remained on the extruded cylindrical body. FIG. 7 shows the opening indices of Comparative Example 2 in order of position number (the entire circumference of the spider 8 is divided into 16), the opening indices vary between 0 and 12, and the variation in the radial opening ratio is 100%. It changes greatly. That is, a portion (,,, 13) of the spider 8 corresponding to the spider member 5
, The opening area is 0, and the opening index is 1 in a portion (,, etc.) corresponding to the opening 13 (see FIG. 4A).
It becomes 2. In Comparative Example 2, rubber, resin or the like formed into a cylindrical shape by the spider member 5 is cut in the flow direction, and the trace is left as a spider mark.

[0035]

As is apparent from the above description,
The extrusion die for a cylindrical body made of rubber, resin or the like of the present invention has the following excellent effects.

(1) The extrusion die for a cylindrical body according to the first aspect is provided with openings arranged intermittently in a plurality of layers arranged concentrically on the spider so as to make the radial opening ratio uniform. By doing so, the amount of rubber, resin, etc. extruded is equal at any position in the outer peripheral direction of the spider, the thickness of the cylindrical body extruded from the nozzle becomes uniform at any position in the outer peripheral direction, and the spider mark No cylindrical body is obtained.

(2) The die for extruding a cylindrical body according to claim 2 is a method for assuming a reference sector shape, in which, instead of the reference length, a sector shape in which the center angle is equally divided is assumed.
This discloses one means for specifying the radial aperture ratio. As in the first aspect, a cylindrical body without spider marks can be obtained.

(3) The cylindrical body extrusion die according to claim 3, wherein the side of the outer peripheral side opening and the side of the central side opening are on the same line when the opening has a sector shape. By lining up,
Since the outer peripheral side opening and the central side opening do not overlap in the radial direction and do not separate from each other, no spider mark is formed on a cylindrical body such as rubber extruded by these openings. .

(4) The cylindrical body extrusion die according to the fourth aspect has a fan-shaped opening, and a radial length of the outer peripheral side opening is shorter than that of the central side opening. Thus, in the same reference sector, the change in the opening area due to the circumferential length of the outer opening being longer than the circumferential length of the center opening is offset by adjusting the radial length. Keep the radial aperture constant.

(5) The extrusion die for a cylindrical body according to the fifth aspect has a sector shape in which an outer peripheral side opening and a center side opening are alternately provided, and a central angle corresponding to each sector is set to be equal to each other. The angles are equally divided according to the number of the sectors, the openings are uniformly distributed over the entire circumference, and the thickness of the extruded cylindrical body is balanced over the entire circumference.

(6) In the cylindrical die extrusion die according to the sixth aspect, the variation in the radial opening ratio is less than 45%.
Spider marks are not generated, and the obtained cylindrical body such as rubber and resin is satisfactory in quality.

[Brief description of the drawings]

FIGS. 1A and 1B show a spider according to a first embodiment of the present invention. FIG. 1A is a front view, and FIG.
It is -A sectional drawing.

FIG. 2 is a front view illustrating a spider according to a second embodiment of the present invention.

FIG. 3 is a front view showing a spider according to Comparative Example 1.

4A and 4B are front views showing a conventional general spider portion. FIG. 4A shows a spider of Comparative Example 2 in which a spider member 5 has a cross shape, and FIG. 4B shows a spider member 5 ′. 2 shows a spider in a spiral shape.

FIG. 5 is a cross-sectional view showing a distal end portion of a general extruder using a conventional spider.

FIGS. 6A and 6B are diagrams showing the radial opening ratio of the spider of the present invention as an index, in which FIG. 6A is calculated for the spider of the first embodiment, and FIG. FIG. 6 (c) shows the results calculated for the spider.
Is calculated for each spider.

FIG. 7 is a diagram showing a radial direction aperture ratio of the spider of Comparative Example 2 as an index.

FIG. 8 is a cross-sectional view illustrating a positional relationship among the spider 8, the mandrel 31, and the mandrel tip 30 according to the first embodiment of the present invention.

[Explanation of symbols]

 1: Barrel 2: Screw 3: Screen 4: Breaker plate 5, 5 ', 5 ": Spider member 6: Mandrel support 7: Extended area 8.8', 8": Spider 9: Outer cylinder 10: Die 11 : Nozzle 12: Spider outer cylinder 31: Mandrel

Claims (6)

[Claims] 1. A cylindrical extrusion die made of rubber, resin, or the like, having a spider provided between an expansion region and a compression region, wherein the spider has a disk shape, and a spider outer cylinder is provided on an outer peripheral side. Is formed, a mandrel support for supporting the mandrel is supported on the inside thereof via a spider member, and the spider member is provided with an opening serving as a flow path for the rubber, resin, or the like, and the opening has a plurality of layers. Assuming a sector that is formed concentrically and intermittently and connects the center point of the spider with both ends of a reference length that equally divides the outer periphery of the spider, the area of the opening in this sector is An extrusion die for a cylindrical body made of rubber, resin, or the like, which is equal in a fan shape. 2. An extrusion die for a cylindrical body made of rubber, resin, or the like, having a spider provided between an expansion region and a compression region, wherein the spider has a disk shape, and a spider outer cylinder is provided on an outer peripheral side. Is formed, a mandrel support for supporting the mandrel is supported on the inside thereof via a spider member, and the spider member is provided with an opening serving as a flow path for the rubber, resin, or the like, and the opening has a plurality of layers. A cylinder made of rubber, resin, or the like, which is formed intermittently in a concentric manner, and assuming a sector shape in which the center angle of the spider is equally divided, the area of the opening is equal in any sector shape. Die for extruding shaped bodies. 3. The fan according to claim 1, wherein the opening has a sector shape provided in two layers, an outer periphery side opening and a center side opening, and an extension of a side of the sector intersects at a center point of the spider.
3. The extension according to claim 1, wherein the extension of the side of the outer peripheral side opening coincides with the side of the center side opening, and the outer peripheral side opening and the center side opening are alternately provided in the outer peripheral direction. Rubber
Extrusion die for cylindrical body made of resin or the like. 4. The opening has a sector shape provided in two layers of an outer peripheral opening and a central opening, and a radial length of the outer peripheral opening is a radius of the central opening. An extrusion die for a cylindrical body made of rubber, resin, or the like according to any one of claims 1 to 3, which is shorter than the length in the direction. 5. The fan according to claim 1, wherein the opening has a sector shape provided alternately in two layers of an outer periphery side opening portion and a center side opening portion in an outer periphery direction of the spider. And the intersection angle is an angle obtained by equally dividing the center angle of the spider according to the number of the openings.
4. A die for extruding a cylindrical body made of rubber, resin, or the like according to any one of 4. 6. A cylindrical extrusion die made of rubber, resin, or the like, provided with a spider between an expansion region and a compression region, wherein the spider has a disk shape, and a spider outer cylinder is provided on an outer peripheral side. Is formed, a mandrel support for supporting the mandrel is supported on the inside thereof via a spider member, and the spider member is provided with an opening serving as a flow path for the rubber, resin, etc., and the opening is formed of a plurality of layers. Assuming that the spiders are formed concentrically and intermittently and connect the center point of the spider and both ends of the reference length obtained by equally dividing the outer periphery of the spider, the areas of the openings in these fan shapes are respectively The opening is configured such that a value obtained by dividing a difference between a maximum value and a minimum value of a value (referred to as an opening ratio in a radial direction) divided by an area of a sector by the maximum value is less than 0.45. Rubber
Extrusion die for cylindrical body made of resin or the like.