KR20070105023A - The extrusion dies with no eccentricity for double wall resin pipe - Google Patents

Abstract

A non-eccentric extrusion mold for manufacturing a double deposition wall pipe is provided to minimize temperature errors between synthetic resins, and to form outer pipes of uniform thickness by forming at least one injection path and maintaining the length of each injection path. A non-eccentric extrusion mold for manufacturing a double deposition wall pipe comprises an outer mold(21), an inner mold(22), a core mold(23), a read molding part(22A), and a front molding part(22B). The outer mold comprises a pipe shaped guide part(G), a hollow(H) and an injection hole. The inner mold comprises an axial direction hollow(H') whose diameter is decreased toward the front end. The core mold is inserted in the hollow of the inner mold in non-contact manner. An injection passage(C) through which molten or half melted synthetic resin is supplied is extended in the rear molding part. The front molding part comprises an outer space(r0) having annular section.

Description

The extrusion dies with no eccentricity for double wall resin pipe}

1 is a cross-sectional structural view of a mold for manufacturing a conventional double-layered wall tube.

Figure 2 is a side view of the inner mold for manufacturing a conventional double laminated wall tube.

Figure 3 is a perspective view of an embodiment of the present invention uncentered extrusion mold.

Figure 4 shows an embodiment of the present invention uncentered extrusion mold,

  (A) is a partial cross-sectional structural diagram showing a state of non-operation,

  (B) is a partial cross-sectional structural diagram showing a state of operation.

5 is a cross-sectional view taken along the line A-A of FIG.

Figure 6 is a side view of an embodiment inner mold constituting the present invention an uneccentric extrusion mold.

Figure 7 is an exploded view of the injection passage formed in the inner mold in one embodiment.

((Explanation of symbols for main parts of drawing))

  11,22. Inner mold 12,23. Core mold 12A. Front core

  12B. Rear core part 13,21. Outer mold 22A. Rear inner mold part

  22B. Front inner mold part

  C. Injection channel C-1. Primary injection flow path C-2. 2nd injection path

  C-2-1. Rear flow path C-2-1. Rear flow path C-2-2. Forward Euro

  C-3. Third injection oil C-3-1. Rear channel C-3-2. Forward Euro

  D. Dam F. Flange G. Guide Section

H. I. hollow injection port P _I. Inner tube

P _O. Outer tube R _R. Rear space R _F. Forward space

r _I. Inner space r _O. Outer space

The present invention, by forming a spiral synthetic resin flow path for the outer tube of two or more wires of the same length on the outer peripheral surface of the inner mold for the extrusion of the inner tube during the manufacture of the double-layer laminated tube in which the inner tube and the outer tube of the round tube tightly bonded, In the eccentric extrusion mold for manufacturing a double layered wall tube, in which the thickness of the outer tube can be uniformly extruded even when both of the outer molds are moved and the inner and outer molds are fixed without adjusting the thickness of the outer tube. It is about.

Generally, synthetic resin pipes are manufactured in the form of straight pipes, in which the inner and main surfaces of the circular cross section have a curvature but form a smooth surface by extruding synthetic resins in a molten or semi-melt state, and before being completely hardened immediately after being extruded in the form of straight pipes. By forming the outer circumferential surface, corrugated pipes with arc-shaped irregularities and spiral tubes with irregularities formed with spirals are manufactured.

Synthetic resin pipes produced by extrusion as described above are mostly single layer wall, that is, in the form of a single pipe, but in the case of a single pipe, there is a problem that the rigidity is insufficient depending on the modification, but if the thickness is manufactured to increase the manufacturing cost There is a problem.

In addition, due to industrialization, the use of synthetic resins is rapidly increasing due to the rapid increase in the use of synthetic resins. However, there is no special countermeasure. However, only waste synthetic resins have been collected so that they are not buried and contaminate soil. A method of recycling it is being studied, and only a few methods are actually applied.

In order to recycle waste synthetic resin which is very important in terms of environmental pollution as mentioned above, synthetic resin tube is closely bonded to outer tube of circular cross section on outer circumferential surface of circular cross section to increase rigidity of synthetic resin tube or to reduce manufacturing cost. Double laminated wall tubes have been developed.

That is, the outer tube is manufactured using the first synthetic resin raw material produced for aesthetic appearance, the inner tube is made of waste synthetic resin, thereby reducing the manufacturing cost of the synthetic resin tube, and the rigidity by adjusting the thickness or material of the inner tube It is also possible to produce improved synthetic resin tubes.

Synthetic resin double laminated wall tube having the above advantages is manufactured by a double extrusion method, look at this as follows.

As shown in Figs. 1 and 2, the extrusion die for manufacturing the double laminated wall tube is circular along the axial direction in the extrusion hole of the inner die 11 having a diameter that varies with position but has an inner circumferential surface of a circular cross section. By inserting and engaging the front part of the core metal mold | die 12 which has the outer peripheral surface of a cross section, the inner space r _I of an annular (or ring-shaped) cross section is formed between the inner metal mold 11 and the core metal mold | die 12. FIG.

Then, the inner die 11 is inserted into the extrusion hole of the outer die 13 having the inner circumferential surface having a circular cross section, and thus, the front die is inserted between the outer circumferential face of the inner die 11 and the inner circumferential face of the outer die 13. The outer space r _O of the annular cross section opened to the end side is formed.

At this time, the core mold 12 is divided into a front core portion 12A inserted into the inner mold 11 and a rear core portion 12B exposed outside the inner mold 11.

And the front end part of the outer side metal mold | die 13 is equipped with the pipe-shaped guide part G for guide | inducing the double laminated wall tube extruded.

In the above-described mold structure, the inner pipe synthetic resin is injected from the rear end side to the front end side of the core mold 12 to form a straight pipe through the inner space r _I between the inner mold 11 and the core mold 12. The inner tube of the form continues to the front side after leaving the front end of the inner mold 11.

Then, the synthetic resin for the outer tube is injected into the rear end of the outer mold and then laminated in close contact with the outer circumferential surface of the inner tube that flows between the outer space r _O and travels out of the front end of the inner mold 12, thereby forming an outer circumferential surface of the inner tube. The inner circumferential surface of the outer tube is laminated in close contact with each other.

At this time, the injection flow path C for introducing the outer pipe synthetic resin injected into the outer circumferential surface of the inner mold 11 into the outer space r _O is the outer circumferential surface of the inner mold 11 in close contact with the inner circumferential surface of the outer mold 13. Formed in a spiral shape along with the outer space (r _O ) of the annular cross-section, the synthetic resin is filled in the outer space (r _O ) through the injection passage (C), and then the synthetic resin is pushed forward by the injection pressure to the inner side. The outer tube is formed on the outer peripheral surface of the tube.

The conventional injection flow path (C) formed as described above, the synthetic resin is introduced into one side of the outer space (r _O ) of the annular cross-section, the synthetic resin is rotated to fill the inside of the outer space (r _O ), the outer space According to the position at (r _O ), the temperature difference between the synthetic resins increases, and as a result, the thickness of the outer tube formed on the outer circumferential surface of the inner tube becomes uneven, thereby degrading the quality.

Therefore, in order to prevent the thickness unevenness of the outer tube as described above, the inner and outer molds 11 and 13 are moved to each other so as to be eccentric with each other, that is, either one of the inner and outer molds 11 and 13. By moving in the direction perpendicular to the axis to adjust the radial distance of the outer space (r _O ) having an annular cross section along the arc, there is also attached a mold eccentric device to adjust the thickness of the outer tube, Not only is the apparatus complicated, but a lot of quality deviations may occur depending on the skill of the operator.

The present invention was devised to solve various problems of the conventional extrusion mold for manufacturing a double-layered laminated pipe, and by forming a plurality of injection passages so that the length of each injection passage is kept constant, each injection The temperature variation between the resins injected through the flow path is minimized, and the productivity can be improved, and the thickness of the outer tube can be uniformly formed even when both the inner and outer molds are fixed without adjusting the eccentricity. It is an object of the present invention to provide an eccentric extrusion mold for producing a double laminated wall tube.

The object of the present invention, after proceeding in a spiral toward the front side in the state of branching twice in equal intervals and the same length along the outer peripheral surface of the inner mold from the synthetic resin inlet extending through the outer mold to the outer peripheral surface of the inner mold It is achieved by two pairs of synthetic resin injection passages which are simultaneously joined and joined with the outer space which is the annular cross-sectional space between the inner and outer molds.

The uneccentric extrusion mold for producing a double-layered laminated wall tube of the present invention is composed of a core mold, an inner mold, and an outer mold like a conventional mold, but has an annular cross section between the front outer peripheral surface of the inner mold and the inner peripheral surface of the corresponding outer mold. In the state in which the outer space is formed, there are technical features of the two pairs of synthetic resin injection passages formed on the outer mold outer peripheral surface located behind the outer space, which will be described below.

At this time, the relative positions of the "front" and "rear" are referred to as the front, the side that proceeds on the basis of the direction in which the extrusion material proceeds, the rear.

The synthetic resin injection flow path is formed from the rear end of the outer circumferential surface of the inner mold to the front end and is a passage for supplying the synthetic resin in a molten or semi-melt state, and starts from the synthetic resin inlet formed through the outer mold.

That is, a pair of "primary injection flow paths" are formed while the injection holes penetrating through the inner and outer peripheral surfaces of the rear end of the outer mold and extending to the outer peripheral surface of the rear end of the inner mold are branched in opposite directions along the outer peripheral surface of the inner mold. Each primary injection passage is again branched into a pair of "secondary injection passages" which will again run in opposite directions.

In addition, a pair of secondary injection passages branched from each primary injection passage also proceed in opposite directions to each other to meet the outer space, which is an annular cross-sectional space between inner and outer molds, drawing a spiral trajectory. The "secondary injection flow path" is divided into a "rear flow path" from the time branched from the primary injection flow path to just before the start of the spiral trajectory, and a "forward flow path" having a spiral trajectory.

As described above, the most important point in the injection flow path branched from the injection port into a pair of primary injection flow passages → two pairs of injection flow passages (two pairs of rear flow passages → two pairs of forward flow passages) and extended to the outer space, Therefore, the length and amount of each synthetic resin injected into the outer space through each of the two pairs of secondary injection channels must be kept the same.

In order to do the above, the branch angles at each branch point must be the same, and the primary and secondary injection passages must be equally spaced from each other so that the amount of synthetic resin flowing into each passage can be exactly the same. In addition, the temperature change of the resin through each flow path can be maintained the same, so that the variation in the thickness of the outer pipe which can be caused by the variation of the resin temperature and the length of the run during each flow path can be prevented or minimized. It becomes possible.

As described above, in order to make the mutual length between a pair of primary injection paths and the mutual length between two pairs of secondary injection paths equal to each other, when viewed on an arcuate cross section, they branch in the left and right directions at the injection port. The center angle between the ends of the two primary injection passages is 180 °, and the center angle between the ends of the initial passages of the two secondary injection passages branching in opposite directions from the ends of each primary injection passage is It should be 90 ° around the tip.

That is, on the circular arc, the ends of the two primary injection flow passages branching along both sides of the upper surface of the circular arc, that is, along the left and right outer circumferential surfaces, are respectively located on the left and right front end surfaces constituting 180 °. The rear flow path ends of the two secondary injection flow paths branching up and down from the end of the primary injection flow path are moved up and down 45 ° from the end of the primary injection flow path, respectively, to have a center angle of 90 ° to each other. Finally, two pairs of trailing end portions of the rear flow path of the secondary injection flow passage are arranged at 90 ° intervals on the arc.

At this time, in the arc-shaped branching structure as described above, the end portion of the primary injection passage in which the secondary injection passage branches and the rear end portion of the rear passage passage in which the spiral forward flow passage starts are inclined in the vertical direction. Since the amount of synthetic resin proceeding to the two branching flow paths is different from each other, the end portion of the primary injection passage and the rear passage end of the secondary injection passage are parallel to the axial direction of the inner mold in the extrusion direction. It must be formed in the direction.

For example, when the secondary injection channel is rebranched in the up and down directions with the primary injection channel formed from the upper portion to the lower portion of the arc, the synthetic resin passing through the primary injection channel is branched upward by inertia. It flows mostly toward the secondary injection channel branched downward rather than the injection channel, and it is extremely difficult or almost impossible to prevent such a phenomenon and to uniformly distribute the synthetic resin on both sides.

However, when branching the secondary injection channel in the up-down direction in a state where the end portion of the primary injection channel is formed in parallel with the extrusion direction, the synthetic resin can be uniformly distributed in both directions.

Of course, gravity may tend to increase the amount of synthetic resin distributed to the downwardly branched secondary injection channel rather than the upwardly branched secondary injection channel, although from the end of the horizontal primary injection channel, As opposed to the downward direction but branched at the same angle, the above difference is sufficiently negligible by the injection pressure of the resin.

Then, the pair of secondary injection passages branching from the end portions of the primary injection passages in the horizontal direction are rear flow paths, and each rear flow passage is formed in the horizontal direction at the end portions after traveling in the up and down directions, respectively. At the end thereof, a forward flow passage of the secondary injection flow passage is formed spirally.

That is, when viewed from a circular cross section, the inlet is maintained at the upper end, the ends of the primary injection channel are at the left and right sides opposite to each other, and the rear channel ends of the secondary injection channel are equally spaced 90 ° from each other. As far as possible, it is located at 45 ° up and down about the end of the primary injection channel, and in the axial direction, the inlet port, the primary injection channel end, and the rear channel end of the secondary injection channel are located in the rear. It becomes the structure arrange | positioned forward.

Due to the structure of the injection channel as described above, all synthetic resins supplied to the injection port and proceeding to each branch flow path move the same distance to reach the outer space, and thus 90 ° equal intervals rather than one side of the rear end of the outer space. The synthetic resin flowing from the two pairs of helical front flow paths of the second injection flow path located in the outer space is uniformly mixed by the helical force in the outer space, filling the inside of the outer space, and then uniformly formed on the outer circumferential surface of the inner tube which is out of the inner circumferential surface of the inner mold front end. Lamination adheres to one thickness.

Details of the effects and the resulting effects, including the object and technical configuration of the present invention will be clearly understood by the following description with reference to the drawings showing a preferred embodiment of the present invention.

3 is a perspective view of the present invention uncentered extrusion die, FIG. 4 is a partial cross-sectional structural view of the present invention uncentered extrusion die, FIG. 5 is a cross-sectional view taken along line AA of FIG. And a side view of the inner mold, a developed view of the injection flow path formed in the inner mold in FIG.

As shown, the non-eccentric extrusion mold of the present invention is provided with a pipe-shaped guide portion G for guiding the double laminated wall pipe extruded at the front end portion, and has a rear space having a substantially cylindrical shape ( R _R ) and the conical front space (R _F ) of which the diameter is significantly reduced toward the front and the hollow (H) of the guide portion (G) are formed through the integrated state from the rear to the front along the axial direction toward the forward, And the outer mold 21 is formed through the injection hole (I) penetrating the outer peripheral surface and the inner peripheral surface on one end:

In the state inserted into the rear space R _R and the front space R _F of the outer mold 21, the outer peripheral surface adjacent to the rear end is in contact with the inner peripheral surface adjacent to the rear end of the outer mold 21 toward the front. The outer peripheral surface is gradually reduced and gradually spaced apart from the inner peripheral surface of the outer mold 21, the annular flange (F) which is in close contact with the rear end surface of the outer mold 21 is provided at the rear end portion, A rear mold portion 22A formed with an injection passage C, which is a passage through which the synthetic resin in the melted or semi-melted state is extruded and is supplied along the outer circumferential surface after being connected to the injection hole I; It is formed extending from the front end of the rear mold portion 22A, the outer peripheral surface is made of a front mold portion 22B further spaced apart from the inner peripheral surface of the outer mold 21 to form an outer space r _O of the annular cross section, With the inner mold 22 through which the axial hollow H 'is further reduced in diameter from the rear end to the front end:

The inner space r _I of the annular cross section between the inner circumferential surface of the inner mold 22 in a state where the outer circumferential surface is inserted into the hollow H 'of the inner mold 22 so as not to contact the inner circumferential surface of the inner mold 22. ) And a core mold 23 whose diameter decreases toward the front from the rear end side of the inner mold 22.

In the case of the inner mold 22 constituting the eccentric extrusion mold for producing a double-layered laminated wall tube configured as described above, both the front and rear mold portions 22B and 22A are inclined toward the front from the rear, and the front mold portion 22B. Inclination of the back mold part 22A is larger than that of the rear mold part 22A.

In addition, the non-eccentric extrusion mold for producing a double-walled laminated tube of the present invention has a technical feature in the injection passage C formed in the structure of the linear groove on the outer circumferential surface of the inner mold 22, which will be described in detail as follows.

The injection passage C is formed on an outer circumferential surface of the rear mold portion 22A of the inner mold 22, and is left on the upper outer circumferential surface of the rear mold portion 22A that meets the lower end of the injection hole I of the outer mold 21. Branching in both right directions forms a pair of primary injection passages (C-1), and each primary injection passage (C-1) branches again in both the upper and lower directions to form a secondary injection passage ( C-2).

At this time, the end of the primary injection channel (C-1) is formed in the horizontal direction, the secondary injection channel (C-2) branching from the horizontal end of the primary injection channel (C-1) is upward or It is divided into a rear channel C-2-1 in which the end portion thereof changes in the horizontal direction after the downward direction, and a spiral front channel C-2-2 starting at the horizontal end of the rear channel C-2-1.

In particular, it is important to form end portions of the first injection passage C-1 and the rear passage C-2-1 in the horizontal direction, and the two primary injection passages C-1 to have the same length of each passage. At the same time, the two end portions of the two rear flow passages C-2-1 branched off from the primary injection flow passage C-1, while the two ends of each side face each other on an arc, that is, have an angle of 180 °, By positioning the injection channel C-1 at a position of 45 ° up and down with respect to the end of the injection channel C-1, the two ends of the rear channel C-2-1 having two pairs are formed at equal intervals of 90 ° on the arc. It should be arranged.

However, the branch structure of the injection channel C may vary, so that a spiral channel is formed immediately without branching at the horizontal end of the primary injection channel C-1, or the secondary injection channel C is formed. A pair of tertiary injection flow paths may be diverted again at the end of each of the rear flow paths (C-2-1) in -2).

That is, the injection passage C formed on the outer circumferential surface of the inner mold 22 constituting the uneccentric extrusion mold for producing a double-layered wall tube of the present invention is composed of at least one pair or more even numbers according to the size and length of the mold, Each flow path is formed to have the same length while being arranged at equal intervals.

In addition, a stepped dam D is formed at the front end of the rear mold portion 22A at which the spiral front passage C-2-2 ends just before the front mold portion 22B starts. By C-2-2), the synthetic resin, which has advanced while rotating between the inner circumferential surface of the inner mold 22 and the inner circumferential surface of the outer mold 21, receives a pressure toward the rear while colliding with the dam D. As a result, in the rear mold portion 22A, a continuous flow is achieved in which the synthetic resin flow between the inner circumferential surface of the inner mold 22 and the inner circumferential surface of the outer mold 21 is seamless.

As described above, the eccentric extrusion mold for manufacturing a double-walled laminated tube of the present invention is formed with a plurality of injection flow paths to be a supply passage of the synthetic resin formed on the outer peripheral surface of the inner mold, each injection because the length of the injection flow path is formed the same By minimizing the temperature variation of the synthetic resin passing through the flow path, not only the variation of the thickness of the outer pipe is minimized, but also the synthetic resin is supplied through a plurality of injection flow paths, thereby increasing productivity.

Claims (8)

An outer mold (21) having a pipe-shaped guide portion (G) at a front end, a hollow (H) formed therethrough, and an injection hole (I) passing through an outer circumference and an inner circumference on one side of the rear end; An inner mold 22 inserted into the outer mold 21 and having an axial hollow H 'penetrated therethrough, the diameter of which decreases from the rear end to the front end; In the mold for producing a double-layered laminated tube, including a core mold 23 inserted and mounted so as not to be in close contact with the hollow H 'of the inner mold 22, The inner mold 22 is connected to the inlet I of the outer mold 21, and the rear mold portion 22A is formed with an injection passage C extending from the outer circumferential surface thereof to supply the synthetic resin in a molten or semi-melt state. Wow; A front edge extending from the front end of the rear mold portion 22A and having a conical outer circumferential surface whose diameter gradually decreases forwardly is spaced apart from the inner circumferential surface of the outer mold 21 to form an outer space r _O of an annular cross section. An eccentric extrusion die for producing a double layered wall tube, characterized in that the mold portion (22B). The pair of injection paths (C) of claim 1, wherein each of the injection passages (C) branches in the left and right sides of the upper outer peripheral surface of the rear mold portion (22A) that meets the lower end of the injection hole (I) of the outer mold (21). A primary injection passage C-1; An eccentric extrusion mold for manufacturing a double layered wall tube, characterized in that the pair consisting of two pairs of secondary injection passages (C-2) branched in both the upper and lower directions at the end of each primary injection passage (C-1). 3. An eccentric extrusion mold for manufacturing a double layered wall tube according to claim 2, wherein an end portion of the primary injection channel C-1 is formed in a horizontal direction. The method of claim 2, wherein the secondary injection flow path (C-2) is a rear flow path (C-2-1) whose end is changed in the horizontal direction after facing in one of the upper and lower directions; An eccentric extrusion mold for manufacturing a double layered wall tube, characterized in that the spiral front channel (C-2-2) starting at the horizontal end of the rear channel (C-2-1). The endless end of each of the pair of primary injection passages (C-1) is located in a position facing each other on the outer circumferential arc, the non-uniform extrusion mold for producing a double laminated wall tube. The endless end of each of said two pairs of secondary injection flow paths (C-2) is arranged in a 90 degree interval on the outer circumferential arc. The pair of injection paths (C) of claim 1, wherein each of the injection passages (C) branches in the left and right sides of the upper outer peripheral surface of the rear mold portion (22A) that meets the lower end of the injection hole (I) of the outer mold (21). A primary injection passage C-1; An eccentric extrusion mold for producing a double layered wall tube, characterized in that the spiral channel formed extending from the end of the primary injection channel (C-1). The pair of injection paths (C) of claim 1, wherein each of the injection passages (C) branches in the left and right sides of the upper outer peripheral surface of the rear mold portion (22A) that meets the lower end of the injection hole (I) of the outer mold (21). A primary injection passage C-1; Two pairs of secondary injection passages C-2 which are branched in both the upper and lower directions at the ends of the respective primary injection passages C-1; Eccentric extrusion mold for manufacturing a double layered wall tube, characterized in that made of three pairs of tertiary injection channel (C-3) which is branched in both up and down directions at the end of each secondary injection channel (C-2). .

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