extruder

Abstract

An extruder has a cylinder and a screw housed in the cylinder. The inner peripheral surface of the cylinder has a first groove forming region (22e) and a second groove forming region (22f) each forming a groove. In the first groove forming region (22e), the height of the ridge (22g) forming the groove (22d) is constant. In the second groove forming region (22f), at least a portion overlaps the material supply port (22a) when viewed in the circumferential direction, and the height of the ridge (22g) forming the groove (22d) is lower than that of the first groove forming region (22e).

Description

Technical Field

[0001] This invention relates to an extruder. Background Technology

[0002] An extruder is known to have a cylinder equipped with a heater and a screw housed in the cylinder, wherein a molding material is melted by heating based on the heater, and the molten molding material is extruded from the extrusion port of the cylinder.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2018-196970 Summary of the Invention

[0006] The problem that the invention aims to solve

[0007] The requirement is to increase the extrusion rate per unit time of the extruder. If the flow rate of molding material into the cylinder increases per unit time, the extrusion rate also increases. Increasing the inner diameter of the cylinder would increase the flow rate, but it would also require a larger extruder, increasing the space needed for installation and raising the manufacturing cost of the extruder.

[0008] The present invention was made in view of the following circumstances, and one of the exemplary objects of one embodiment of it is to provide a technique that can increase the flow rate of molding material into the extruder without making the extruder larger.

[0009] Methods for solving problems

[0010] To address the aforementioned issues, an extruder according to one embodiment of the present invention includes a cylinder and a screw housed within the cylinder. The inner circumferential surface of the cylinder has a first groove forming region and a second groove forming region, which respectively form grooves. In the first groove forming region, the height of the ridge forming the groove is constant. In the second groove forming region, at least a portion overlaps with the material supply port when viewed circumferentially, and the height of the ridge forming the groove is lower than that of the ridge forming the first groove forming region.

[0011] Furthermore, any combination of the above-mentioned constituent elements, or the substitution of the constituent elements of the present invention with each other in methods, apparatus, systems, etc., are also valid embodiments of the present invention.

[0012] Invention Effects

[0013] According to the present invention, the amount of molding material flowing into the extruder can be increased without increasing the size of the extruder. Attached Figure Description

[0014] Figure 1 This is a cross-sectional view of the extruder in the embodiment.

[0015] Figure 2 yes Figure 1 A three-dimensional view of the main body of the first cylinder block.

[0016] Figure 3 yes Figure 1 End view of the main body of the first cylinder block.

[0017] Figure 4 Therefore Figure 3 The unfolded diagram of the main body section cut along line AA.

[0018] Figure 5 yes Figure 4 BB line section view. Detailed Implementation

[0019] Hereinafter, the embodiments for carrying out the present invention will be described in detail with reference to the accompanying drawings. In the description of the drawings, the same elements are labeled with the same symbols, and repeated descriptions are omitted where appropriate.

[0020] Figure 1 This is a cross-sectional view of the extruder 100 according to the embodiment. Figure 1 This is a cross-sectional view of the extruder 100 taken with a vertical section including the central axis C of the cylinder 10 (described later). The extruder 100 is connected to an inflatable film forming machine, a cast film forming machine, a laminating device, or other devices, and supplies them with molten molding material.

[0021] The extruder 100 includes: a cylindrical cylinder 10; a screw 12 housed in the cylinder 10; a hopper 14 for filling molding material and supplying molding material to one end side of the cylinder 10 (hereinafter referred to as the upstream side); and a support member 16 for supporting the upstream side of the cylinder 10 and supporting the hopper 14.

[0022] Hereinafter, the direction parallel to the central axis C of the cylindrical internal space S of the cylinder 10 will be taken as the axial direction, the direction passing through the central axis C on the plane perpendicular to the central axis C will be taken as the radial direction, and the direction along the circumference of the circle centered on the central axis C on the plane perpendicular to the central axis C will be taken as the circumferential direction.

[0023] The cylinder block 10 includes a first cylinder block portion 18 and a second cylinder block portion 20 sequentially from the upstream. The first cylinder block portion 18 and the second cylinder block portion 20 are cylindrical components with substantially the same inner diameter and are coaxially connected.

[0024] The first cylinder block portion 18 includes: a cylindrical main body portion 22; a cooling portion 23 surrounding the downstream side of the main body portion 22; and a cover portion 24 surrounding the cooling portion 23. The main body portion 22 and the cooling portion 23, and the cooling portion 23 and the cover portion 24 are respectively joined by welding.

[0025] An opening, namely a material supply port 22a, is formed on the upstream side of the outer peripheral surface of the main body 22. A refrigerant flow path (not shown) is formed in the cooling section 23. Cooling water or other refrigerant flows through this flow path. As described above, the cooling section 23 surrounds the downstream side of the main body 22, thereby cooling the downstream side of the main body 22. A refrigerant flow path (not shown) is also formed in the support member 16. The upstream side of the main body 22 is cooled by the support member 16 surrounding the upstream side. If the molding material melts in the first cylinder section 18, it loses its propulsion force, and thus the molding material will not enter the downstream side. However, by cooling the main body 22 through the cooling section 23, this situation can be avoided.

[0026] Multiple heaters 26 are wound around the outer periphery of the second cylinder section 20. The heaters 26 heat the interior of the second cylinder section 20 to a temperature that melts the molding material. An extrusion port 20a for extruding molten molding material is formed on the downstream end face of the second cylinder section 20.

[0027] Bolt 32 is inserted axially into the flange portion 20b of the second cylinder portion 20 and the cover portion 24 of the first cylinder portion 18, and screwed into the threaded hole 16b formed in the support member 16, thereby fastening the second cylinder portion 20 and the first cylinder portion 18 together to the support member 16.

[0028] The screw 12 is housed within the internal space S of the cylinder 10. The screw 12 includes a circularly oriented screw shaft 28 extending axially and a helical screw thread 30 forming on the outer periphery of the screw shaft 28. The screw 12 is driven to rotate by a rotary drive device (not shown) connected to one end of the screw 12, and rotates within the internal space S about the central axis of the screw shaft 28. This rotation of the screw 12 causes the molding material to move towards the extrusion port 20a.

[0029] The support member 16 supports the upstream side of the cylinder body 10 and the hopper 14. The upstream side of the main body 22 of the first cylinder body 18 is embedded in the support member 16, and the material supply port 22a is located inside the support member 16. A communication hole 16a is formed in the support member 16, which connects the interior of the hopper 14 and the interior of the main body 22 of the first cylinder body 18.

[0030] The hopper 14 is filled with molding material. The molding material falls from the hopper 14 into the connecting hole 16a of the support member 16, and is supplied to the interior of the main body 22, i.e., the interior space S of the cylinder 10, via the material supply port 22a.

[0031] The above describes the basic structure of the extruder 100. Next, its operation will be explained. The molding material filled in the hopper 14 falls into the connecting hole 16a of the support member 16 and flows into the internal space S of the cylinder 10 via the material supply port 22a. The flowing molding material moves downstream due to the rotation of the screw 12. At this time, the molding material melts due to heat from the inner wall of the cylinder 10 (i.e., heating based on the heater 26) and shear heat generated by being sheared by the screw 12. The molten molding material is extruded from the extrusion port 20a.

[0032] Next, the structure of the main body 22 of the first cylinder block 18 will be described in more detail.

[0033] Figures 2-4 This is a diagram representing the main body 22. Figure 2 This is a three-dimensional view of the main body 22. Figure 3 This is an end view of the main body 22, which is cut by a vertical section perpendicular to the central axis C, i.e., a vertical section that cuts across the material supply port 22a. Figure 3 The arrow indicates screw 12 ( Figure 3 The direction of rotation (not shown in the figure). Figure 4 Therefore Figure 3 The unfolded view of the main body 22, which is cut along line AA and unfolded. Figure 4 The illustration of slot 22d is omitted.

[0034] The inner peripheral surface 22b of the main body 22 has a region where a groove 22d is formed, namely a groove forming region 22c. The main body 22 in this embodiment is not limited to this, and may have a groove forming region 22c that extends throughout its entire inner peripheral surface 22b. The groove 22d is formed on the inner peripheral surface 22b of the main body 22, thereby improving the shape friction effect between the inner peripheral surface 22b of the main body 22 and the molding material, and thus increasing the conveying force of the molding material.

[0035] Groove 22d is a groove extending in a spiral shape along the axial direction. The spiral extension of groove 22d provides a higher form friction effect compared to a non-spiral extension. Furthermore, the direction of the spiral of groove 22d is opposite to the direction of the spiral of the screw thread 30, resulting in an even higher form friction effect compared to a groove with the same direction. A higher form friction effect increases the conveying force of the molding material. Additionally, groove 22d is not limited to a spiral extension; for example, it can be a groove extending in a straight line along the axial direction.

[0036] The groove forming region 22c has a first groove forming region 22e and a second groove forming region 22f. Figure 4 In the diagram, the area enclosed by the dashed line is the first groove forming area 22e, and the area enclosed by the single-dot dashed line is the second groove forming area 22f.

[0037] The first groove forming region 22e is a region where the height of the hill 22g forming the groove 22d is constant. In other words, the first groove forming region 22e is a region where the distance from the central axis C to the top of the hill 22g is constant. Furthermore, the "height" of the hill 22g is the radial distance between the top of the hill 22g and a cylindrical reference plane P centered on the central axis C. In this example, the reference plane P is the cylindrical surface passing through the deepest part of the groove.

[0038] The second groove forming region 22f is the region where the height of the hill 22g forming groove 22d is lower than that of the hill 22g in the first groove forming region 22e. In other words, the second groove forming region 22f is the region where the distance from the central axis C to the hill 22g is longer. The second groove forming region 22f is not particularly limited; in this example, the hill 22g is higher the farther it is from the material supply port 22a. In other words, the farther the hill 22g is from the material supply port 22a, the longer the distance from the central axis C to the hill 22g. Furthermore, the second groove forming region 22f is not particularly limited; in this example, each hill 22g is higher the farther it is from the material supply port 22a. In other words, the farther each hill 22g is from the material supply port 22a, the longer the distance from the central axis C.

[0039] The second groove forming region 22f is set axially ( Figure 4 The range Rf in the left-right direction (in the middle) at least partially overlaps with the range Ra in the axial direction of the material supply port 22a.

[0040] In the illustrated example, the second groove forming region 22f is configured such that its axial extent Rf is wider than the axial extent Ra of the material supply port 22a, and completely overlaps with the extent Ra. In other words, the second groove forming region 22f is configured such that its axial extent Rf includes the axial extent Ra of the material supply port 22a. Furthermore, the second groove forming region 22f is configured to extend from an upstream side (specifically, the upstream end face 22h of the main body 22) to a downstream side of the material supply port 22a.

[0041] The second groove forming region 22f is located near the circumferential material supply port 22a and on both sides of the circumferential direction of the material supply port 22a. The second groove forming region 22f is preferably configured to extend circumferentially from the material supply port 22a (i.e., continuous with the material supply port 22a). In this example, the second groove forming region 22f is provided on both sides of the circumferential direction of the material supply port 22a, but it is also possible to provide the second groove forming region 22f only on one side of the circumferential direction of the material supply port 22a.

[0042] On the other hand, the portion of the inner circumferential surface 22b adjacent to the material supply port 22a in the axial direction ( Figure 4The portion to the right and left of the material supply port 22a does not form the second groove forming region 22f, but in this example, the first groove forming region 22e is formed. Of course, it is not limited to this, and the second groove forming region 22f may also be formed in these portions.

[0043] The second groove forming region 22f can also be formed by cutting the mountain part 22g of the first groove forming region 22e. That is, it can also be done in the following way: first, the groove forming region 22c is formed as a whole as the first groove forming region 22e, and the second groove forming region is formed by cutting a part of the mountain part 22g, that is, a part of the first groove forming region is changed into the second groove forming region 22f.

[0044] By designating the groove forming region 22c near the material supply port 22a as a second groove forming region 22f where the mountain 22g is lower than the first groove forming region 22e, instead of the first groove forming region 22e, the internal space S of the cylinder 10 near the material supply port 22a is correspondingly widened. In other words, an arc-shaped space (bag portion) Sa for the molding material to enter is formed between the virtual circle passing through the apex of the mountain 22g of the first groove forming region 22e and the line connecting the apex of the mountain of the second groove forming region. The wider internal space S increases the inflow of molding material per unit time, resulting in an increase in the extrusion rate.

[0045] Furthermore, the second groove forming region 22f extends downstream of the material supply port 22a, thus widening the internal space S of the downstream side of the material supply port 22a due to the formation of the second groove forming region 22f. Although molding material also falls downstream from the material supply port 22a, the increased internal space S of the downstream side of the material supply port 22a (i.e., the extrusion port 20a side) further increases the inflow of molding material per unit time, resulting in a further increase in the extrusion volume.

[0046] Furthermore, even if the second groove forming region 22f extends upstream of the material supply port 22a, it will hardly or completely contribute to the increase of extrusion volume because it is on the opposite side of the extrusion port 20a. However, when the second groove forming region 22f is formed by cutting the mountain part 22g of the first groove forming region 22e, if the second groove forming region extends from the end face 22h of the main body 22, the processing of forming the second groove forming region 22f becomes easier.

[0047] Figure 5 yes Figure 4The BB-line cross-sectional view shows that, axially, the hill 22g of the second groove forming region 22f is connected to the hill of the first groove forming region 22e via an inclined portion to prevent the formation of a stepped portion between the hill 22g of the first groove forming region 22e and the hill 22g of the second groove forming region 22f. This reduces the flow resistance of the molding material and increases the conveying force of the molding material compared to the case where a stepped portion is formed.

[0048] According to the embodiment described above, a higher extrusion volume can be achieved using an extruder 100 of the same size as a conventional extruder. Conversely, an extrusion volume of the same level as a conventional extruder can be achieved using an extruder 100 that is smaller than a conventional extruder.

[0049] The present invention has been described above according to embodiments. Those skilled in the art should understand that these embodiments are merely examples, and the combination of each component and processing step can have various modifications, and such modifications are also within the scope of the present invention. Modifications will be described below.

[0050] Any combination of the above-described embodiments and variations is also effective as an embodiment of the present invention. New embodiments resulting from such combinations possess the effects of both the combined embodiments and variations.

[0051] Industrial availability

[0052] This invention relates to an extruder.

[0053] Symbol Explanation

[0054] 10-Cylinder body, 12-Screw, 18-First cylinder body section, 20-Second cylinder body section, 22-Main body section, 22a-Material supply port, 22b-Inner circumferential surface, 22c-Gutter forming area, 22d-Gutter, 22e-First groove forming area, 22f-Second groove forming area, 22g-Mountain section, 100-Extruder.

Claims

1. An extruder, characterized in that, have: Cylinder block; and The screw is housed within the cylinder. The inner circumferential surface of the cylinder has a first groove forming region and a second groove forming region, respectively forming grooves. In the region where the first trough forms, the height of the mountain forming the trough is constant. In the second groove forming region, the axial extent of the groove at least partially overlaps with the axial extent of the material supply port, and the height of the hill forming the groove is lower than that of the hill forming region of the first groove. In a cross section orthogonal to the axial direction, the higher the hill in the hill formed in the second groove forming region, the further away from the material supply port it is.

2. The extruder according to claim 1, characterized in that, The second groove forming area is located near the material supply port in the circumferential direction.

3. The extruder according to claim 1 or 2, characterized in that, The second groove forming area extends axially to a position downstream of the material supply port.

4. An extruder, characterized in that, have: Cylinder block; and The screw is housed within the cylinder. The inner circumferential surface of the cylinder has a first groove forming region, a second groove forming region, and another second groove forming region different from the first second groove forming region in a cross section orthogonal to the axial direction and transverse to the material supply port. In the region where the first trough forms, the height of the mountain forming the trough is constant. In the second trough-forming region and the other second trough-forming region, the height of the mountain forming the trough is lower than that of the mountain forming the first trough-forming region. In the circumferential direction, the second groove forming region is disposed between the material supply port and the first groove forming region, and the other second groove forming region is disposed on the side opposite to the second groove forming region relative to the material supply port, between the material supply port and the first groove forming region.

5. The extruder according to claim 4, characterized in that, The second groove forming region and the other second groove forming region extend axially to a position downstream of the material supply port.

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