JP2015196355A - Breaker plate and extruder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a breaker plate having a new structure that can suppress stagnation of a material flow and the like.SOLUTION: A breaker plate includes first through holes arranged on the circumference of a first circle having a first radius to form a through hole row on the outermost periphery, and second through holes arranged on the circumference of a second circle, having a second radius smaller than the first radius, arranged concentrically with the first circle. The first through hole extends so that a direction connecting the center of the first circle and an opening of the first through hole formed on one surface side and a direction connecting the center and an opening of the first through hole formed on the other surface side form a first torsion angle. The second through hole extends so that a direction connecting the center of the second circle and an opening of the second through hole formed on one surface side and a direction connecting the center of a breaker plate and an opening of the second through hole formed on the other surface side form a second torsion angle. The second torsion angle is larger than the first torsion angle.

Description

  The present invention relates to a breaker plate and an extruder.

  In the extruder, a breaker plate is disposed in front of the screw of the extruder. Various techniques have been proposed for breaker plates (see, for example, Patent Documents 1 to 5). For example, when extruding engineering plastic and rubber materials, especially high-filling and high-viscosity materials, the resin flow stays around the breaker plate, causing resin burning, material decomposition, and increased load on the screw. In some cases, normal extrusion may not be possible.

JP-A-5-16207 JP-A-6-20544 Japanese Utility Model Publication No. 7-21327 JP 2007-118519 A Japanese Patent No. 4163148

  An object of the present invention is to provide a breaker plate having a novel structure capable of suppressing retention of a material flow and the like, and an extruder using such a breaker plate.

According to one aspect of the present invention,
A breaker plate having a plurality of concentric rows of through-hole rows formed by arranging a plurality of through-holes on the circumference,
A first through hole disposed on the circumference of a first circle having a first radius and forming an outermost through hole array;
A second through-hole disposed on the circumference of a second circle having a second radius smaller than the first radius and concentric with the first circle;
A direction connecting the center of the first circle and the opening of the first through hole formed on one surface side of the breaker plate, and the first formed on the other surface side of the center and the breaker plate. The first through hole extends such that a direction connecting the openings of the through holes forms a first twist angle;
A direction connecting the center and the opening of the second through hole formed on one surface side of the breaker plate, and an opening of the second through hole formed on the other surface side of the center and the breaker plate. The second through-hole extends so that the direction of connection forms a second twist angle;
A breaker plate having a second twist angle larger than the first twist angle is provided.

According to another aspect of the invention,
A cylinder,
A screw disposed in the cylinder;
A breaker plate disposed in front of the screw and having a plurality of concentric rows of through-hole rows formed by arranging a plurality of through-holes on the circumference;
The breaker plate is
A first through hole disposed on the circumference of a first circle having a first radius and forming an outermost through hole array;
A second through-hole disposed on the circumference of a second circle having a second radius smaller than the first radius and concentric with the first circle;
A direction connecting the center of the first circle and the opening of the first through hole formed on one surface side of the breaker plate, and the first formed on the other surface side of the center and the breaker plate. The first through hole extends such that a direction connecting the openings of the through holes forms a first twist angle;
A direction connecting the center and the opening of the second through hole formed on one surface side of the breaker plate, and an opening of the second through hole formed on the other surface side of the center and the breaker plate. The second through-hole extends so that the direction of connection forms a second twist angle;
An extruder having the second twist angle larger than the first twist angle is provided.

  Inflow into the breaker plate by increasing the second torsion angle of the second through hole arranged radially inward relative to the first torsion angle of the first through hole arranged in the outermost through hole row It becomes easy to pass the material to be smoothly passed.

FIG. 1 is a schematic sectional view showing an example of the structure of an extruder according to an embodiment of the present invention. 2A to 2C are a front view, a cross-sectional view, and a side view of the screw model assumed in the simulation, respectively. 3A and 3B are a plan view and a cross-sectional view of the cylinder model assumed in the simulation, respectively, and FIG. 3C is a schematic cross-sectional view showing an overall analysis model. FIG. 4A is a vector diagram showing the flow of the molding material at the screw tip position, and FIG. 4B is a graph showing the radial distribution of the molding material flow at the screw tip position. FIG. 5A is a perspective view schematically showing the flow of the molding material in the vicinity of the tip of the screw, and FIG. 5B is a perspective view schematically showing the through hole shape of the breaker plate according to the embodiment. 6A and 6B are a schematic plan view and a cross-sectional view, respectively, of a breaker plate according to a first example of the embodiment, and FIG. 6C is a schematic plan view of a breaker plate according to a second example. 6D is a schematic plan view of a breaker plate according to a third example. 7A and 7B are a schematic plan view and a cross-sectional view, respectively, of a breaker plate according to a comparative embodiment, and FIG. 7C is a schematic plan view showing a broken state of the breaker plate according to the comparative embodiment. 7E is a schematic plan view and a cross-sectional view of a breaker plate according to a comparative example, respectively. FIG. 8 is a table summarizing the screw rotation speed, breaker plate structure, and evaluation results in Examples and Comparative Examples.

  An extruder according to an embodiment of the present invention will be described with reference to FIG. Drawing 1 is an outline sectional view showing an example of the structure of extrusion molding machine 100 by an embodiment. The extrusion molding machine 100 according to this example is formed including an extruder 10, a cross head 20, and a transport mechanism 30.

  The extruder 10 is formed to include a hopper 11, a cylinder 12, a screw 13, and a breaker plate 14. The molding material 40 is introduced into the inlet of the cylinder 12 through the hopper 11. The molding material 40 in this example is an insulating resin material. The molding material 40 is heated and melted in the cylinder 12, is kneaded by the rotation of the screw 13, and moves to the front side of the screw 13. A rough movement direction of the molding material 40 is indicated by an arrow AR.

  A breaker plate 14 is disposed in front of the screw 13. The molding material 40 that has moved to the tip of the screw 13 passes through the through hole of the breaker plate 14 and is injected into the crosshead 20. The breaker plate 14 is a rectifying member that improves flow uniformity in a plane that intersects the flow of the molding material 40. The breaker plate 14 also has a function of removing large foreign matters. For convenience of explanation, the cross section of the breaker plate 14 shown in FIG. 1 is indicated by X-shaped hatching. A specific cross-sectional shape example of the breaker plate 14 according to the embodiment will be described later with reference to FIG. 6B.

  The crosshead 20 includes a mandrel 21, a die 22, and a housing 23 that houses the mandrel 21 and the die 22. The conveyance mechanism 30 includes a core wire sending machine 31 and a cable winder 32.

  By the rotation of the screw 13 of the extruder 10, the molding material 40 injected into the crosshead 20 further passes between the mandrel 21 and the die 22 and is extruded from the die 22 so as to have a desired cross-sectional shape. . At the same time, the core wire 50 delivered from the core wire delivery machine 31 is inserted into the cross head 20 via the mandrel 21, passes through the molding material 40 injected between the mandrel 21 and the die 22, 22 is sent out of the crosshead 20.

  In the opening of the die 22, the core wire 50 passes through the center, and the molding material 40 passes outside the core wire 50. Thus, the extrusion molding which coat | covers the molding material (insulating resin material) 40 around the core wire 50 can be performed, and the insulated cable 60 in which the insulation coating 41 was formed in the core wire 50 can be formed. The cable winder 32 winds the insulated cable 60. The rotational speed of the screw 13 (the extrusion speed of the molding material 40), the delivery speed of the core wire 50 from the core wire delivery machine 31, and the like can be controlled by the control device 70 so as to satisfy appropriate conditions. These appropriate conditions can be determined experimentally, for example.

  The insulating resin material 40 is, for example, polybutylene naphthalate (PBN). The core wire 50 is made of, for example, tin-plated copper wire and has a diameter of, for example, 2.5 mm. The insulation cable 60 has a thickness of the insulation coating 41 of, for example, 0.35 mm, and a total diameter of the core wire 50 and the insulation coating 41 of, for example, 3.2 mm.

  Next, an extrusion molding machine according to a comparative form and a problem that easily occurs in the comparative form will be described. The comparative extrusion molding machine is different from the extrusion molding machine of the embodiment in the structure of the breaker plate. Other structures are the same as in the embodiment.

  7A and 7B are respectively a schematic plan view and a cross-sectional view of a breaker plate 114 according to a comparative example (a cross-sectional view in the thickness direction viewed from a line of sight perpendicular to the thickness direction, and AA shown in the plan view 7A. FIG. The breaker plate 114 has a circular planar shape, and has a plurality of through holes 115 that are constant in thickness and penetrate in the thickness direction. The opening shape of each through-hole 115 is a circle having a predetermined diameter.

  One through-hole 115 is arranged at the center of the breaker plate 114, and the other through-holes 115 are arranged concentrically around the center. More specifically, a plurality of through-hole rows in which a plurality of through-holes 115 are arranged side by side on the circumference are formed in a concentric manner. In the example shown in FIGS. 7A and 7B, two rows of through-hole rows are formed, the inner through-hole row has six through-holes 115 arranged at intervals of 60 °, and the outer through-hole row. Has twelve through-holes 115 arranged at intervals of 30 °.

  In the breaker plate 114 according to the comparative form, the extending direction of all the through holes 115 is parallel to the thickness direction. That is, the length directions of all the through holes 115 are perpendicular to the screw side surface (inflow side surface) into which the molding material flows or the screw opposite surface (outflow side surface) from which the molding material flows out. Yes.

  In the extruder using the breaker plate 114 according to the comparative form, for example, when an engineering plastic type or rubber type material is extruded, particularly a high-filling / high-viscosity material, the resin burns due to the residence of the resin flow around the breaker plate. And the material is decomposed, and the load on the screw is increased, which makes it difficult to perform normal extrusion. Moreover, as shown in FIG. 7C, when extruding a high-viscosity material, there is also a phenomenon in which a portion between the through holes arranged on the outermost circumference (portion indicated by a broken line) is continuously broken.

  The inventor of the present application proposes a breaker plate capable of suppressing such a problem as described below. First, as a preliminary study, a simulation for examining the flow state of the molding material in the extruder will be described. This simulation was performed using Particleworks (registered trademark) manufactured by Promec Software Co., Ltd., which is simulation software based on a particle method.

  2A to 2C are a front view and a sectional view of the screw model SC assumed in the simulation (a longitudinal sectional view as seen from a line of sight perpendicular to the longitudinal direction, in the AA direction shown in the front view 2A. It is sectional drawing) and a side view. The screw SC has a root portion and a screw portion. A screw portion having a length of 88 mm is attached to a root portion having a diameter of 28 mm and a length of 28 mm. The screw portion includes a screw structure portion in which blades are formed around the screw shaft, and a tip portion that is disposed in front of the screw structure portion and has a diameter that decreases toward the front.

  The screw structure portion has a root side portion, a tip side portion, and an intermediate portion arranged between the root side portion and the tip side portion, and the diameter of the shaft of the root side portion is 20 mm. The diameter of the shaft of the part is 24 mm, and the diameter of the shaft of the middle part changes so as to increase from the root side toward the tip side. The length of the root portion is 28 mm, the length of the root portion and the intermediate portion is 56 mm, and the total length of the screw structure portion including the root portion, the intermediate portion and the tip portion is 84 mm. The total length of the screw part obtained by adding the screw structure part and the tip part is 88 mm.

  The diameter of the screw blade is 28 mm, and one pitch of rotation of the screw blade is 28 mm. The thickness of the screw blade is 4 mm.

  3A and 3B are a plan view (top view seen from the inlet side) and a sectional view (side sectional view seen from the side) of the cylinder model CY assumed in the simulation, respectively. FIG.

  The outer width of the cylinder CY is 40 mm, and the length is 168 mm (40 mm + 128 mm). The diameter of the cylinder chamber formed inside the cylinder, containing the screw and injected with the molding material is 28 mm. On the central axis of the cylinder CY at one end of the cylinder CY, an outlet portion having a diameter of 8 mm serving as an outlet for the molding material is formed. The cylinder chamber and the outlet portion are connected at an intermediate portion whose diameter narrows toward the outlet portion. The outlet side of the cylinder CY is called the downstream side, and the opposite side is called the upstream side.

  In a plan view, an inlet having a width of 8 mm and a length of 24 mm is formed on the upstream side of the central axis of the cylinder CY. The length from the end on the outlet side (downstream side) of the cylinder CY to the end on the upstream side of the inlet is 128 mm. The length from the end (downstream side) end of the cylinder chamber (connection position with the intermediate portion) to the upstream end of the inlet is 100 mm. The length of the intermediate part is 24 mm. The length from the upstream end of the cylinder CY to the upstream end of the inlet is 40 mm.

  3C is a schematic cross-sectional view (a side view seen from the side) showing an overall analysis model in which the screw model SC shown in FIGS. 2A to 2C and the cylinder model CY shown in FIGS. 3A and 3B are combined. FIG. For ease of illustration, the screw SC shows a side view instead of a sectional view.

  Z-axis extending in the direction of the rotational axis of the screw SC and the central axis of the cylinder CY, Y-axis extending in the direction from the rotational axis of the screw SC and the central axis of the cylinder CY toward the inlet of the cylinder CY, and the Z-axis And an XYZ orthogonal coordinate system having an X axis orthogonal to the Y axis. The screw SC rotates in the XY plane, and the molding material is extruded in the Z direction.

  A screw SC is disposed in the cylinder chamber. In the cylinder chamber, a breaker plate BP is further arranged in front of the screw SC. The center of the breaker plate BP is disposed on the rotation axis of the screw SC.

  The breaker plate model BP assumed in the simulation has the same structure as the breaker plate 114 of the comparative form described with reference to FIGS. 7A and 7B. The breaker plate BP has a diameter of 28 mm and a thickness of 8 mm. The diameter of the through hole is 4 mm. The breaker plate BP has one through hole arranged at the center, an inner through hole array having six through holes arranged at intervals of 60 ° on the circumference having a diameter of 10 mm, and a circumference having a diameter of 20 mm. And an outer through-hole row having 12 through-holes arranged at intervals of 30 °. The distance between the tip of the screw SC and the screw side (upstream side) surface of the breaker plate BP is 4 mm.

Other conditions for the analysis are as follows. A Newtonian laminar flow model with constant viscosity was used as the calculation model. The particle diameter was 0.5 mm, and the number of particles was about 300,000 particles. The density of the molding material was 1000 kg / m ^3, and the viscosity of the molding material was 1000 Pa · sec. The inflow speed of the molding material to the inlet of the cylinder CY was 5 mm / sec, and the screw rotation speed was 30 rpm. The outlet pressure at the outlet of the cylinder CY was 0 Pa.

  Next, simulation results will be described with reference to FIGS. 4A and 4B. FIG. 4A is a vector diagram showing the flow of the molding material at the screw tip position. The left part shows an overall view and the right part shows an enlarged view. The flow of the molding material increases as it moves away from the rotation axis (Z-axis) in the radial direction, and tends to decrease as it approaches the cylinder inner surface beyond the vicinity of the center from the rotation axis to the cylinder inner surface.

  FIG. 4B is a graph showing a radial direction (Y direction) distribution of the flow of the molding material at the screw tip position. FIG. 4B shows the flow vector of the molding material in an exploded manner in a rotational direction (circumferential direction, X direction) velocity component Vx and an extrusion direction (axial direction, Z direction) velocity component Vz. Hereinafter, the vector notation and the vector magnitude notation may be used without distinction.

  The horizontal axis indicates the Y-direction position, that is, the radial position in mm, the Y-direction position 0 mm indicates the rotation axis center, and the Y-direction position 14 mm indicates the cylinder inner surface position. The vertical axis indicates the flow rate in mm / sec. The rotational flow rate (X direction component) is indicated by a rhombus plot, and the extrusion flow rate (Z direction component) is indicated by a square plot.

  The extrusion direction flow velocity shows a distribution that is substantially constant in the radial direction. On the other hand, the rotational flow velocity increases as the distance from the rotation axis increases, reaches a maximum near the center between the rotation axis and the cylinder inner surface, and further exhibits a parabolic radial distribution that decreases as the cylinder inner surface is approached. As described above, it was found from the above simulation that the flow of the molding material in the vicinity of the screw tip has a distribution in which the flow velocity in the rotational direction varies greatly in the radial direction.

  The breaker plate according to the comparative form has a through hole extending in parallel with the thickness direction, that is, the extrusion direction. Therefore, if the flow of the molding material is a flow having only a component in the extrusion direction, the flow smoothly passes through the through holes of the breaker plate.

  However, as described above, the flow of the molding material also has a rotational direction component, and the magnitude of the rotational direction component has a distribution that varies greatly in the radial direction. Therefore, when the breaker plate of the comparative form is used, the rotational direction component of the flow is likely to cause a large flow disturbance near the breaker plate, resulting in problems such as retention of molding material (resin) and increased pressure. It is considered a thing.

  Therefore, the inventor of the present application proposes the breaker plate 14 according to the embodiment having a through-hole shape in consideration of the rotational direction component in addition to the extrusion direction component of the flow of the molding material as described below. First, the through hole 15 included in the breaker plate 14 according to the embodiment will be described.

  FIG. 5A is a perspective view schematically showing the flow of the molding material in the vicinity of the screw tip (near the cylinder tip). The flow has an extrusion direction component Vz and a rotation direction component Vx, and a flow vector Vx + Vz obtained by combining these components is directed obliquely forward of the screw. The magnitude of the extrusion direction component Vz indicates a distribution Dz that is substantially constant in the radial direction (Y direction), and the magnitude of the rotational direction component Vx is a parabolic distribution as described above in the radial direction (Y direction). Dx is shown.

  FIG. 5B is a perspective view schematically showing the shape of the through hole 15 of the breaker plate 14 according to the embodiment. The through hole 15 connects an opening OP1 formed on the screw side surface (inflow side surface) of the breaker plate 14 and an opening OP2 formed on the screw opposite surface (outflow side surface) of the breaker plate 14. An opening OP1 is formed at a position separated from the center P of the breaker plate 14 by a distance r. The thickness of the breaker plate 14 is L.

  As a vector Vz indicating the extrusion direction component of the flow at the position of the opening OP1, a vector Vx indicating the rotation direction component, and a vector parallel to the combined flow vector Vx + Vz, vectors Uz, Ux and Ux + Uz are respectively obtained. Show. The ratio of the vectors Uz, Ux, Ux + Uz to the magnitudes of the vectors Vz, Vx, Vx + Vz is determined so that the magnitude of the vector Uz is equal to the thickness L of the breaker plate 14.

  The flow in the vicinity of the screw tip is represented by the vector Vx + Vz as described above and heads diagonally forward of the screw. Therefore, if the extension direction of the through-hole 15 of the breaker plate 14 is set to be obliquely shifted so as to be shifted from the thickness direction (extrusion direction) to the circumferential direction (rotation direction) so as to follow the flow, the breaker plate The flow of the molding material passing through can be made smoother than in the comparative embodiment.

  The preferable extending direction of the through hole 15 can be estimated by the following concept. If the molding material that has flowed into the inflow opening OP1 of the breaker plate 14 flows as it is, the molding material proceeds in the thickness direction by the thickness L of the breaker plate 14, that is, by the vector Uz, and at the same time, in the circumferential direction by the vector Ux. Will only reach the outflow side surface. Therefore, the outflow side opening OP2 may be disposed at the tip of the combined vector Ux + Uz.

  Such a relationship is expressed by the following equation. The direction connecting the center P of the breaker plate 14 and the center of the opening OP1 and the center of the center P of the breaker plate 14 and the center of the opening OP2 (in the XY plane, that is, in plan view as viewed from the thickness direction of the breaker plate 14) Let θ be the angle formed by the direction connecting. Since the opening OP2 can be regarded as being disposed at a position where the opening OP1 is twisted by an angle θ, the angle θ is referred to as a “twist angle θ”.

  In terms of the twist angle θ, when the molding material advances by L in the extrusion direction at a speed Vz, the molding material advances in the rotation direction by rtan θ at a speed Vx. That is, the relationship Vx: Vz = rtanθ: L is established, and can be expressed as tanθ = LVx / (rVz). A preferable value of the twist angle θ can be estimated so as to satisfy such a relationship, and the through hole 15 can be formed so as to have an extending direction corresponding to the twist angle θ.

  Next, the overall structure of the breaker plate 14 will be described. First, the breaker plate 14 according to the first example will be described with reference to FIGS. 6A and 6B.

  6A and 6B are a schematic plan view and a sectional view (thickness direction sectional view in the AA direction shown in the plan view 6A) of the breaker plate 14 according to the first example of the embodiment, respectively. The breaker plate 14 has a structure in which a plurality of through holes 15 are formed in a plate-like member 14BS having a circular planar shape and a constant thickness. The opening arrange | positioned on the screw side surface (inflow side surface) of each through-hole 15 is shown with a broken line, and the opening arrange | positioned on the screw opposite side surface (outflow side surface) is shown with a continuous line. The opening shape of each through hole 15 is circular. In addition, the through-hole inner surface visible with the line of sight seen from the outflow side is shown by hatching.

  One through hole 15P is arranged at the center of the breaker plate 14, and the other through holes 15 are arranged concentrically around the center. A plurality of through holes 15 are arranged on a circumference 17 concentric with the center of the breaker plate 14 to form a through hole row 16. Reference numerals a, b, and c are attached from the outside to the inside of the breaker plate 14 to distinguish the through holes 15 and the through hole rows 16. The breaker plate 14 according to the first example has three rows of through-hole rows 16a to 16c.

  The outermost through-hole row 16a is formed by 18 through-holes 15a arranged at intervals of 20 ° on the circumference 17a. A through-hole row 16b adjacent to the inside of the through-hole row 16a is formed by twelve through-holes 15b arranged at intervals of 30 ° on the circumference 17b. The six through-holes 15c arranged at intervals of 60 ° on the circumference 17c form an adjacent (innermost) through-hole row 16c inside the through-hole row 16b.

  The extending direction of the central through hole 15P is parallel to the thickness direction. The extending direction of the other through holes 15 excluding the central through hole 15P is slanted so as to deviate from the thickness direction of the breaker plate 14 in the circumferential direction, and is a direction connecting the center of the breaker plate and the screw side opening. The direction connecting the center of the breaker plate and the screw opposite side opening forms a twist angle θ. The central through hole 15P can also be regarded as a through hole having a zero twist angle θ.

  As described above, the flow rate in the rotation direction of the molding material shows a radial distribution that is maximized between the rotation shaft and the cylinder inner surface. Correspondingly, the torsion angle θ is determined so as to have a distribution that is relatively large between the center and the outer periphery of the breaker plate 14 and relatively smaller as the distance from the center and the outer periphery is increased. Is preferred.

  In the breaker plate 14 according to the first example, the twist angle θa of the through-hole 15a forming the outer through-hole row 16a and the twist angle θa of the outer through-hole row 16a with respect to the twist angle θb of the through-hole 15b forming the intermediate through-hole row 16b The torsion angles θc of the through holes 15c forming the through hole row 16c are set to be small. In this manner, by arranging three rows (or three or more rows) of through-hole rows, it becomes easy to form a twist angle distribution corresponding to the radial direction distribution of the rotational flow velocity.

  In this example, the inflow side openings of the through holes 15P and 15a to 15c are arranged on the same straight line in a certain direction (up and down direction on the paper surface). The cross-sectional view shown in FIG. 6B is a cross-sectional view passing on such a straight line. The left side is the inflow side and the right side is the outflow side.

  The central through hole 15P has an extending direction parallel to the thickness direction, and has a constant thickness and opens on the outflow side surface. The through hole 15b has the largest torsion angle θ and does not open to the outflow side on this straight line. The other through-holes 15a and 15c are open to the outflow side on this straight line, but by having a twist angle θ, the opening width on this straight line is narrower on the outflow side than the inflow side. .

  Next, with reference to FIG. 6C, the breaker plate 14 by the 2nd example of embodiment is demonstrated. FIG. 6C is a schematic plan view of the breaker plate 14 according to the second example. In the first example, three through-hole rows are formed, whereas in the second example, two through-hole rows are formed.

  In the second example, the twist angle of the through hole 15b forming the inner through hole row 16b is set larger than the twist angle of the through hole 15a forming the outer through hole row 16a. The central through hole 15P can be regarded as having a zero twist angle, as in the first example.

  In the first example, the through holes 15a having a relatively small twist angle are provided on both sides (outside and inside) of the through hole row 16b that is disposed in the middle in the radial direction and has the through holes 15b having a relatively large twist angle. , 15c having through-hole rows 16a and 16c are arranged.

  On the other hand, in the second example, the through-hole row 16a having the through-hole 15a having a relatively small twist angle is arranged only outside the through-hole row 16b having the through-hole 15b having a relatively large twist angle θ. Yes. However, a central through hole 15P having a twist angle of zero is arranged inside the through hole row 16b. Thereby, even when the number of through-hole rows is two, it is possible to form a twist angle distribution corresponding to the radial direction distribution of the rotational flow velocity.

  In addition, even when the number of through-hole rows is two rows or three or more rows, (any) through-holes arranged on the inner side with respect to the torsion angle of the through-holes of the outermost through-hole rows The torsion angle of the through hole in the row is set large. Thereby, it is possible to form at least a twist angle distribution corresponding to the radial distribution of the rotational flow velocity from the cylinder inner surface (from the screw outer side) toward the rotation axis.

  Next, with reference to FIG. 6D, the breaker plate 14 by the 3rd example of embodiment is demonstrated. FIG. 6D is a schematic plan view of the breaker plate 14 according to the third example. In the first example and the second example, the opening shape of the through hole 15 is circular, but the opening shape of the through hole 15 is not limited to a circular shape. For example, as in the example shown in FIG. 6D, an opening shape in which the center portion of the sector shape is cut out may be used. Thus, even if the opening shape is other than a circle, it is possible to form a through-hole having an appropriate twist angle based on the above-described concept.

  The extrusion molding machine 100 according to the embodiment uses the breaker plate 14 according to the embodiment as described in the first to third examples, for example, as the breaker plate of the extruder 10. As a result, the flow of the molding material passing through the breaker plate can be made smoother than in the comparative embodiment, so that the resin flow around the breaker plate can cause resin burning or material decomposition or be applied to the screw. Problems such as an increase in burden and the inability to perform normal extrusion can be suppressed.

  In the above description, an example using a crosshead die as the extrusion molding machine 100 according to the embodiment is illustrated, but the breaker plate 14 according to the embodiment is applied to other types of molding machines, for example, those using a straight die. However, the same effect can be obtained.

  In the description of the above embodiment, for convenience of explanation, the expression of the screw side (inflow side) and the screw opposite side (outflow side) is used for the one side surface and the other side surface of the breaker plate 14. You may invert these mutually. That is, the surface described as the screw side (inflow side) in the above description is arranged on the screw opposite side (outflow side), and the surface described as the screw opposite side (outflow side) in the above description is the screw side (inflow side). The breaker plate 14 according to the embodiment has the same effect with respect to the same rotation direction of the screw.

  Next, an evaluation experiment using the breaker plate according to the above-described embodiment will be described. An extrusion experiment was conducted on a material in which about 50% magnesium hydroxide was included as a filler in polybutylene naphthalate (PBN), which is an engineering plastic. The experimental conditions were as follows. A screw having a diameter of 28 mm and a length of 1120 mm was used. The extrusion temperature of the cylinder and the head was constant at 200 ° C., and the screw rotation speed was changed to 20 rpm, 30 rpm, and 40 rpm. In addition to the experiment (Example) using the embodiment of the breaker plate, an experiment (Comparative Example) using the comparison plate was also performed.

  The breaker plates used in the examples were assumed to have three rows of through-hole rows, similar to the first example of the embodiment (see FIG. 6A). The torsion angles of the through holes forming the first, second and third through hole rows from the center side of the breaker plate were respectively θ1, θ2, and θ3, and the torsion angles θ1 to θ3 were variously changed.

  The torsion angles θ1 to θ3 obtained from the simulation corresponding to each screw speed were set as ideal values θs1 to θs3. The ideal values when the screw speed is 20 rpm are θs1 of 16 °, θs2 of 40 °, and θs3 of 10 °. The ideal values when the screw speed is 30 rpm are θs1 of 24 °, θs2 of 60 °, and θs3 of 15 °. The ideal values when the screw speed is 40 rpm are θs1 of 32 °, θs2 of 80 °, and θs3 of 20 °.

  At each screw rotation speed, the ideal value θs2 of the torsion angle of the through hole in the middle in the radial direction is larger than the ideal values θs1 and θs3 of the torsion angles of the through holes on the center side and the outer periphery side. Moreover, the ideal value of the torsion angle increases corresponding to the increase in the rotational flow velocity as the screw rotation speed increases (see also FIG. 5B). In general, the torsion angle in each embodiment is set so as to correspond to the tendency of the ideal value.

  The breaker plate of the example has a diameter of 28 mm, and through-hole rows of the first, second, and third rounds are formed on concentric circles having a diameter of 8 mm, a diameter of 16 mm, and a diameter of 24 mm, respectively. . The opening of the through hole is circular and has a diameter of 2 mm. Through holes are arranged at 60 ° intervals on the first round, 30 ° intervals on the second round, and 20 ° intervals on the third round. The thickness of the breaker plate is 8 mm. As a material of the breaker plate, for example, stainless steel SUS304 can be used, and through holes can be formed by, for example, electric discharge machining so as to have a desired arrangement, opening shape, twist angle, and the like.

  As shown in the plan view of FIG. 7D and the cross-sectional view of FIG. 7E, the breaker plate used in the comparative example had only through holes parallel to the thickness direction, and three concentric through hole rows were formed. Is. The arrangement of the through holes and the thickness of the breaker plate are the same as those of the breaker plate of the example.

  Resin pressure (motor load) under each experimental condition and appearance abnormality due to burning / decomposition were evaluated, and comprehensive quality determination was performed. The resin pressure was measured by the load current applied to the motor. The screw extruder used in this experiment is stopped by the limiter control when the motor load exceeds 80%.

  FIG. 8 is a table summarizing the screw rotation speed, breaker plate structure, and evaluation results in Examples and Comparative Examples. When the breaker plate of the comparative example was used, if the screw rotation speed was as low as 30 rpm or less, burning or material decomposition occurred (Comparative Example 1 and Comparative Example 2). When the screw speed was increased to 40 rpm to prevent burning and material decomposition, burning was not observed, but the resin pressure increased as the extrusion continued and the motor stopped due to overload. (Comparative Example 3).

  On the other hand, when the breaker plate according to the example is used, no burning occurs even when the screw rotation speed is slowed down to 20 rpm (Example 1), and even if the screw rotation speed is increased to 40 rpm, the motor load is extremely high. There was no increase (Examples 5 and 6). Even at an intermediate screw rotation speed of 30 rpm, motor load and burning problems did not occur (Examples 2 to 4). Thus, it was found that by adopting the twist angle in the through hole of the breaker plate, the motor load can be reduced and the burning / decomposition can be suppressed.

  In Examples 2 to 4, the twist angle θ1 and the twist angle θ3 are equal, and the twist angle θ2 is different. The torsion angle θ2 is set equal to the ideal value θs2 in the third embodiment and deviates from the ideal value θs2 in the second and fourth embodiments. In Examples 2 to 4, Example 3 shows the lowest motor load.

  In Examples 5 and 6, the torsion angle θ1 and the torsion angle θ3 are equal, and the torsion angle θ2 is different. The torsion angle θ2 is set equal to the ideal value θs2 in the sixth embodiment and deviates from the ideal value θs2 in the fifth embodiment. The sixth embodiment shows a lower motor load than the fifth embodiment.

  From the comparison between the results of Example 2 to Example 4 and the comparison between the results of Example 5 and Example 6, it was found that the effect of reducing the motor load and the like can be further increased as the twist angle is made closer to the ideal value. .

  As can be seen from the comparison results between Example 1 to Example 6 and Comparative Example 1 to Comparative Example 3, the resin pressure ( The effect of reducing the motor load) and the effect of suppressing the appearance abnormality due to burning / decomposition can be remarkably obtained.

  As described above, the flow of the material passing through the breaker plate can be smoothed by adopting the twist angle in the through hole of the breaker plate. In addition, the torsion angle formed by the direction connecting the center of the breaker plate and the through hole opening on one surface side and the direction connecting the center of the breaker plate and the through hole opening on the other surface side is defined as the diameter of the breaker plate. By distributing the material so that it is relatively large in the middle of the direction and relatively small as it moves away from the center side and the outer peripheral side, the material flow can be made smooth in a wide area in the plane.

  As mentioned above, although this invention was demonstrated along embodiment, this invention is not restrict | limited to these. It will be apparent to those skilled in the art that various modifications, improvements, combinations, and the like can be made.

DESCRIPTION OF SYMBOLS 10 Extruder 11 Hopper 12 Cylinder 13 Screw 14,114 Breaker plate 14BS Disk-shaped member 15,15a, 15b, 15c, 15P, 115 Through-hole 16,16a, 16b, 16c Through-hole row | line | column 17,17a, 17b, 17c Circle Perimeter 20 Crosshead 21 Core 22 Die 23 Housing 30 Conveying mechanism 31 Core wire feeder 32 Cable winder 40 Molding material 41 Insulation coating 50 Core wire 60 Insulation cable 70 Controller 100 Extruder SC Screw CY Cylinder BP Breaker plate Vx Rotation Directional flow velocity Vz Extrusion direction flow velocity Dx Rotational direction flow velocity magnitude radial distribution Dz Extrusion direction flow velocity magnitude radial distribution OP1, OP2 (through-hole) openings θ, θa, θb, θc, θ1, θ2, θ3 , Θs1, θs2, θs3 Twist angle P Breaker cap Center of rate r Distance from center of breaker plate to through hole opening L Breaker plate thickness Ux Vector Uz parallel to rotational flow velocity Uz Vector parallel to extrusion flow velocity

Claims (5)

A breaker plate having a plurality of concentric rows of through-hole rows formed by arranging a plurality of through-holes on the circumference,
A first through hole disposed on the circumference of a first circle having a first radius and forming an outermost through hole array;
A second through-hole disposed on the circumference of a second circle having a second radius smaller than the first radius and concentric with the first circle;
A direction connecting the center of the first circle and the opening of the first through hole formed on one surface side of the breaker plate, and the first formed on the other surface side of the center and the breaker plate. The first through hole extends such that a direction connecting the openings of the through holes forms a first twist angle;
A direction connecting the center and the opening of the second through hole formed on one surface side of the breaker plate, and an opening of the second through hole formed on the other surface side of the center and the breaker plate. The second through-hole extends so that the direction of connection forms a second twist angle;
A breaker plate in which the second twist angle is larger than the first twist angle. further,
A first circle that is concentric with the first circle and the second circle and is arranged on a circumference of a third circle having a third radius smaller than the second radius, and forms an innermost through hole array; 3 through holes,
A direction connecting the center and the opening of the third through hole formed on one surface side of the breaker plate, and an opening of the third through hole formed on the other surface side of the center and the breaker plate The third through-hole extends so that the direction of connection forms a third twist angle;
The breaker plate according to claim 1, wherein the third twist angle is smaller than the second twist angle. further,
The breaker plate according to claim 1, wherein the breaker plate has a through hole disposed at the center and extending in a direction parallel to a thickness direction of the breaker plate. A disk-shaped member;
A plurality of through holes formed in the disk upper member;
The angle formed by the direction connecting the center of the disk-shaped member and the opening on one surface side of the through-hole and the direction connecting the center of the disk-shaped member and the opening on the other surface side of the through-hole. The plurality of through-holes are formed so that the twist angle has a distribution that is relatively large in the middle in the radial direction of the disk-shaped member, and relatively small as it moves away from the center side and the outer peripheral side. Breaker plate. A cylinder,
A screw disposed in the cylinder;
A breaker plate disposed in front of the screw and having a plurality of concentric rows of through-hole rows formed by arranging a plurality of through-holes on the circumference;
The breaker plate is
A first through hole disposed on the circumference of a first circle having a first radius and forming an outermost through hole array;
A second through-hole disposed on the circumference of a second circle having a second radius smaller than the first radius and concentric with the first circle;
A direction connecting the center of the first circle and the opening of the first through hole formed on one surface side of the breaker plate, and the first formed on the other surface side of the center and the breaker plate. The first through hole extends such that a direction connecting the openings of the through holes forms a first twist angle;
A direction connecting the center and the opening of the second through hole formed on one surface side of the breaker plate, and an opening of the second through hole formed on the other surface side of the center and the breaker plate. The second through-hole extends so that the direction of connection forms a second twist angle;
An extruder having a second twist angle larger than the first twist angle.