A plasticizing device for rubber extruder

Abstract

The present invention provides a rubber extruder plasticizing device, belonging to the technical field of rubber extrusion machinery. The plasticizing device comprises a barrel, and a screw is arranged in the barrel; the screw comprises a feeding section, a plasticizing section and a conveying section; the outer walls of the feeding section and the conveying section are both provided with conveying threads, the plasticizing section is a cylindrical structure, and the outer wall of the plasticizing section is provided with a plasticizing element; the plasticizing element comprises a mounting portion and a dumbbell portion, and the mounting portion is an annular body arranged at intervals on the outer wall of the plasticizing section; the dumbbell portion comprises a cylindrical rod and a sphere located at both ends of the cylindrical rod, the middle part of the cylindrical rod is obliquely fixed on the mounting portion, and a plurality of dumbbell portions are fixed on the annular outer wall of each mounting portion, and the dumbbell portions on adjacent mounting portions are staggered, so that all dumbbell portions are arranged in a spiral shape when viewed along the length direction of the screw. The present invention improves the mixing ability and plasticizing ability of the rubber extruder by innovatively designing the plasticizing device of the extruder, and achieves a balance between extrusion output and plasticizing effect.

Description

Technical Field

[0001] The invention relates to the technical field of rubber extrusion machinery, in particular to a plasticizing device for a rubber extruder. Background Art

[0002] In the existing single-screw rubber cold-feed pin barrel extruder, the rubber material fed into the extruder is stirred, mixed, heated, plasticized, etc. under the joint action of the screw, barrel, and pins, and finally extruded through the die head at a certain extrusion temperature. In this process, the extrusion capacity, extrusion temperature, and plasticization capacity are interrelated in the "devil's triangle" relationship. It is almost impossible to ensure that all three are optimal at the same time.

[0003] The process goal of the cold feed extruder is to achieve the highest extrusion output and the best plasticizing effect under the premise of controllable extrusion rubber temperature. The basic structural type of the cold feed extruder is to install an integral screw into a pin barrel with an inner diameter slightly larger than the outer diameter of the screw. The main extrusion processing area of ​​the rubber is formed between the inner surface of the barrel and the outer surface of the screw. The material properties of the rubber change section by section during the extrusion process. According to the changing characteristics of the rubber state, it can be divided into three areas along the extrusion direction: solid conveying, plasticizing and melting, and melt conveying. They are also called the feeding section, plasticizing section and extrusion section of the extruder. Different functional sections have different screw rib structure designs and pin arrangement types. The rubber in the feeding section is in a highly elastic state, the rubber in the plasticizing section changes from a highly elastic state to a viscous flow state, and the rubber in the extrusion section is in a viscous flow state. In order to facilitate analysis and research, extrusion output, plasticizing effect and extrusion glue temperature are defined as the three elements of extrusion performance; feeding, plasticizing and extrusion are defined as the three elements of extrusion function, and the current extrusion mechanism that uses the same set of barrel and screw component combination to synchronously realize the three functional elements of "feeding, plasticizing and extrusion" is vividly summarized as a "1-1-1" three-stage synchronous extrusion mechanism.

[0004] Current extrusion theory research and production practice have proved that the three elements of extrusion performance cannot reach the ideal high-efficiency value area at the same time. If you want to increase the extrusion output, you must reduce the plasticizing effect, and the extrusion glue temperature will increase; if you want to improve the plasticizing effect, you need to reduce the extrusion glue temperature and extrusion output at the same time. The three show a mutually restrictive "devil's triangle" phenomenon. Therefore, in extrusion production practice, you can only choose to achieve a balance between extrusion output and plasticizing effect within the extrusion glue temperature range permitted by the process. Therefore, improving the mixing and plasticizing capabilities of the rubber extruder is the current direction for optimizing the working efficiency of the rubber extruder. Summary of the invention

[0005] The purpose of the present invention is to provide a rubber extruder screw and a plasticizing device in response to the above-mentioned problems. The present invention aims at the "devil's triangle" defect existing in the existing single-screw rubber cold feed pin barrel extruder, innovatively reconstructs the current extrusion mechanism based on the decoupling of key elements, effectively separates the plasticizing device and the extrusion device of the rubber extruder, and improves the mixing ability and plasticizing ability of the rubber extruder through innovative design of the plasticizing device of the extruder, thereby achieving a balance between extrusion output and plasticizing effect.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is as follows:

[0007] A rubber extruder screw, the screw comprising a feeding section, a plasticizing section and a conveying section arranged in sequence; the outer side walls of the feeding section and the conveying section are both provided with conveying threads, the plasticizing section is a cylindrical structure, and the outer side wall of the plasticizing section is provided with a plasticizing element; the plasticizing element comprises a mounting portion and a dumbbell portion, the mounting portion is an annular body arranged at intervals on the outer side wall of the plasticizing section; a plurality of dumbbell portions are fixed on the annular outer side wall of each mounting portion, the dumbbell portion comprises a columnar rod and two spheres, the columnar rod is fixed on the mounting portion, and the two spheres are respectively located at both ends of the columnar rod.

[0008] In the present invention, preferably, the middle portion of the columnar rod is tilted and fixed on the mounting portion, and the dumbbell portions on adjacent mounting portions are staggeredly installed, so that when viewed along the length direction of the screw rod, all the dumbbell portions are arranged in a spiral shape.

[0009] In the present invention, preferably, the angle between the central axis of the columnar rod and the central axis of the screw is 8-12°.

[0010] In the present invention, preferably, the columnar rod is a cylindrical rod, the diameter of the cylindrical rod is 1 / 9 to 1 / 7 of the working diameter of the outer surface of the plasticizing section, the diameter of the sphere is 1 / 6 to 1 / 4 of the working diameter of the outer surface of the plasticizing section, and the center distance of the spheres at both ends of the same cylindrical rod is 3 / 8 to 5 / 8 of the working diameter of the outer surface of the plasticizing section.

[0011] In the present invention, preferably, the distance between the cylindrical rod and the plasticizing section is 1 / 32 to 3 / 32 of the working diameter of the outer surface of the plasticizing section, the mounting parts are arranged at equal intervals in the plasticizing section, and the distance between adjacent mounting parts is 7 / 10 to 1 of the working diameter of the outer surface of the plasticizing section; the number of dumbbell parts on each mounting part on the same screw is the same.

[0012] In the present invention, preferably, the length ratios of the feeding section, the plasticizing section and the conveying section are all 1:1.5 to 2.5:1.

[0013] The present invention also provides a rubber extruder plasticizing device using the above-mentioned screw, including a barrel, in which one or two horizontally arranged screws are arranged, both ends of the screw are rotatably connected to the bearing seat outside the barrel end through bearings, and one end of the screw is driven to rotate by a power device.

[0014] In the present invention, preferably, when two screws are arranged in the barrel, the two screws are respectively a fast screw and a slow screw, and are driven by different power devices. The feeding sections, plasticizing sections and conveying sections of the two screws are aligned respectively, and the mounting parts on the plasticizing section of the fast screw and the mounting parts on the plasticizing section of the slow screw are aligned one by one and have the same total number. The number of dumbbell parts on each mounting part on the plasticizing section of the fast screw is less than the number of dumbbell parts on each mounting part on the plasticizing section of the slow screw, and the dumbbell parts on the plasticizing section of the fast screw are partially meshed with the dumbbell parts on the plasticizing section of the slow screw.

[0015] In the present invention, preferably, the ratio of the number of dumbbell parts on each mounting part on the fast screw plasticizing section to the number of dumbbell parts on each mounting part on the slow screw plasticizing section is 1:2, 1:3 or 1:4.

[0016] In the present invention, preferably, the feeding section of the fast screw and the feeding section of the slow screw are provided with conveying threads with opposite thread directions and meshing with each other, and the conveying section of the fast screw and the conveying section of the slow screw are provided with conveying threads with opposite thread directions and meshing with each other.

[0017] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0018] In the present invention, the screw includes a feeding section, a plasticizing section and a conveying section arranged in sequence. The outer walls of the feeding section and the conveying section are provided with conveying threads, and their functions focus on conveying the rubber material; the plasticizing section is a cylindrical structure, and its outer wall is provided with a dumbbell-shaped plasticizing element, and its functions focus on stirring, mixing and plasticizing. Such a design allows the plasticizing section to have the conveying function of the existing technology and increase the plasticizing capacity of the plasticizing section.

[0019] The present invention improves the existing pin type into a dumbbell type structure. The balls at both ends of the dumbbell type structure can make the shear contact surface larger. The setting direction of the columnar rod changes the shear direction of the original pin mode. The shapes and sizes of the various parts of the dumbbell type structure are different. These factors work together to increase the mixing, stirring and shearing effects, thereby improving the plasticizing effect. The dumbbell-shaped structures are staggered on the screw, and the dumbbell part is spirally arranged from the length direction of the screw. On the one hand, this structure can make the spirally arranged plasticizing device have the plasticizing ability while maintaining the conveying function; on the other hand, the pins of the existing pin-type structure are fixed to the inner wall of the barrel and will not rotate during the working process. The rubber material is sheared and plasticized while flowing; while the dumbbell-shaped structure in the present invention is fixed to the outer wall of the screw, it can rotate with the rotation of the screw, which enhances its stirring and shearing strength on the rubber material, and the shearing effect makes the rubber material in the barrel as a whole be subjected to the force, and the mixing and stirring are more uniform.

[0020] In the plasticizing device of the twin-screw extruder of the present invention, two screws are arranged in parallel, the number of dumbbell parts on each mounting part of the plasticizing section of the slow screw is in integer multiple relationship with the number of dumbbell parts on each mounting part of the plasticizing section of the fast screw, and partial meshing is formed between the dumbbell-shaped structures of the two screws. When in use, the speeds of the two screws are adjusted to different multiples of rotation speeds, and the shearing efficiency of the dumbbell parts on the rubber material is adjusted by the difference in the rotation speeds of the two screws, so that the rubber material inside the barrel is subjected to two different degrees of shearing, so as to achieve the purpose of adjusting and improving the shearing effect of the rubber material, and the plasticizing section can have stronger mixing and stirring capabilities, thereby improving the mixing ability and plasticizing ability of the rubber extruder on the rubber material.

[0021] When setting the size ratio of each part of the screw, the present invention designs parameters such as the diameter of the cylindrical rod, the diameter of the sphere, the center distance of the sphere, the distance between the columnar rod and the plasticizing section, and the spacing of the mounting parts, so as to achieve a balance between a more compact layout, lower material costs, better plasticizing effects, and higher output. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a front view of a screw rod of a rubber extruder provided by the present invention;

[0023] Figure 2 It is a stereoscopic diagram of a screw rod of a rubber extruder provided by the present invention;

[0024] Figure 3 It is a functional schematic diagram of a rubber extruder plasticizing device provided by the present invention;

[0025] Figure 4 yes Figure 3 View along AA direction;

[0026] Figure 5 yes Figure 3 View along BB direction;

[0027] Figure 6 yes Figure 5 View along CC direction;

[0028] Figure 7 yes Figure 5 View along DD direction.

[0029] Figure 8 This is a view of two screws used in pairs;

[0030] Fig. 9 yes Figure 8 Cross-sectional view along the EE direction.

[0031] Among them, 10-fast screw, 11-feeding section, 12-plasticizing section, 121-mounting part, 122-cylindrical rod, 123-sphere, 13-conveying section, 20-slow screw, 21-feeding section, 22-plasticizing section, 221-mounting part, 222-cylindrical rod, 223-sphere; 23-conveying section, 30-feeding end bearing seat, 40-barrel, 401-feed port, 402-discharge port, 50-discharge end bearing seat, 60-bearing one, 70-bearing two, 80-bearing three. DETAILED DESCRIPTION

[0032] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. The drawings are only for illustrative purposes and represent only schematic diagrams, not physical drawings, and cannot be understood as limitations on this patent. In order to better illustrate the specific implementation methods of the present invention, some parts of the drawings may be omitted, enlarged or reduced, and do not represent the size of the actual product. It is understandable to those skilled in the art that some well-known structures, parts and their descriptions in the drawings may be omitted. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0033] In the description of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "disposed" and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0034] The purpose of the present invention is to improve the existing extrusion screw to optimize the "devil's triangle" relationship between the three functional elements of "feeding, plasticizing, and extruding", improve the mixing ability and plasticizing ability of the rubber extruder, and achieve a balance between extrusion output and plasticizing effect. In this embodiment, an improved rubber extruder screw is first proposed, see Figure 1 and Figure 2 The screw comprises a feeding section 11, a plasticizing section 12 and a conveying section 13 which are arranged in sequence. The screw is integrally formed but the functions and structures of each part are different. The outer walls of the feeding section 11 and the conveying section 13 are provided with conveying threads for conveying rubber materials. The plasticizing section 12 is a cylindrical structure, which is quite different from the existing screw structure. The outer wall of the plasticizing section 12 is provided with a plasticizing element. The plasticizing element comprises a mounting portion 121 and a dumbbell portion. The mounting portion 121 is an annular body arranged at intervals on the outer wall of the plasticizing section 12, which is used to install and fix the dumbbell portion, and can be welded with the outer wall of the plasticizing section 12. The dumbbell part includes a columnar rod 122 and a sphere 123 located at both ends of the columnar rod 122. The middle part of the columnar rod 122 is tilted and fixed on the mounting part 121, preferably fixed by welding, and preferably the angle between the central axis of the columnar rod 122 and the central axis of the screw is 8-12°, more preferably 10°. A plurality of dumbbell parts are fixed on the annular outer wall of each mounting part 121. The number of dumbbell parts can be two or more, and the dumbbell parts on adjacent mounting parts 121 are staggered, so that all dumbbell parts are arranged in a spiral shape when viewed along the length direction of the screw. The present invention improves the existing pin type into a dumbbell type structure. The spheres at both ends can make the shear contact surface larger. The setting direction of the columnar rod 122 changes the shear direction of the original mode, and the shapes and sizes of the various parts of the dumbbell type structure are different. These factors work together to increase the mixing, stirring and shearing effects, thereby improving the plasticizing effect. The columnar rod 122 is tilted so that the multiple dumbbells are arranged in a spiral shape along the length of the screw, so that the plasticizing section of the present invention can not only convey the material but also help plasticize the rubber material.

[0035] When the screw of the present invention is implemented, the technical personnel in this field can set the specific size according to the design specifications. As long as the above-mentioned technical features are met, they are within the protection scope of the present invention. However, in order to achieve a balance between a more compact layout, lower material costs, better plasticizing effect, and higher output, the present invention also optimizes the parameters. Specifically, the columnar rod 122 can be a cylindrical rod 222 or a square columnar rod. The cylindrical rod 222 is now used to illustrate the specific design. The diameter of the cylindrical rod 222 is 1 / 9 to 1 / 7 of the working diameter of the outer surface of the plasticizing section 12, preferably 1 / 8. The diameter of the sphere 123 is 1 / 6 to 1 / 4 of the working diameter of the outer surface of the plasticizing section 12, preferably 1 / 5. The center distance of the spheres 123 at both ends of the same columnar rod 122 is 3 / 8 to 5 / 8 of the working diameter of the outer surface of the plasticizing section 12, preferably 1 / 2. The distance between the columnar rod 122 and the plasticizing section 12 is 1 / 32 to 3 / 32 of the working diameter of the outer surface of the plasticizing section 12, preferably 1 / 16. The mounting parts 121 are arranged at equal intervals in the plasticizing section, and the distance between adjacent mounting parts 121 is 7 / 10 to 1, preferably 4 / 5, of the working diameter of the outer surface of the plasticizing section 12. The length ratio of the feeding section 11, the plasticizing section 12 and the conveying section 13 is 1:1.5 to 2.5:1, preferably 1:2:1. The relationship between the above dimensions is the preferred reference value during design. In the specific implementation, those skilled in the art can make any combination and optimization of the above parameters, which are all within the protection scope of the present invention.

[0036] In the embodiment provided by the present invention, the screw is also applied to the plasticizing device of the rubber extruder to achieve its plasticizing extrusion function. The plasticizing device of the rubber extruder includes a barrel 40, in which one screw or two screws arranged horizontally side by side can be arranged. Figure 5 The two ends of the screw are rotatably connected to the feeding end bearing seat 30 and the discharging end bearing seat 50 on the outer sides of the two ends of the barrel 40 through bearings, and one end of the screw is driven to rotate by a power device (not shown). When designed as a twin-screw plasticizing device, the two screws can be exactly the same or have some differences in structure. A feed port 401 is provided on one side of the top of the barrel 40, and a discharge port 402 is provided on one side of the bottom. The feed port 401 is located above the screw feeding section 11, and the discharge port 402 is located below the screw conveying section 13.

[0037] Another preferred embodiment is that two screws are arranged in the barrel 40, namely a fast screw 10 and a slow screw 20, see Figure 3-7The positional relationship and similarity between the fast screw 10 and the slow screw 20 are that the feeding sections (11, 21), the plasticizing sections (12, 22) and the conveying sections (13, 23) of the fast screw 10 and the slow screw 20 are aligned respectively, the mounting portion 121 on the plasticizing section 12 of the fast screw 10 and the mounting portion 221 on the plasticizing section 22 of the slow screw 20 are aligned one by one, and the ends of the fast screw 10 and the slow screw 20 close to the feeding sections (11, 21) are rotatably mounted in the feeding end bearing seat 30 through bearing two 70 and bearing three 80, and the ends protrude from the outside of the feeding end bearing seat 30, and the outer surface of the protruding part is provided with a spline groove for connecting to an external reduction box and a driving motor, and the feeding end bearing seat 30 can be fixed to the outer wall of one end of the barrel 40 by bolts. The ends of the fast screw 10 and the slow screw 20 near the conveying section (13, 23) are rotatably connected to the discharge end bearing seat 50 through a bearing 60. In this embodiment, the feed port 401 is located above the feeding section 11 of the fast screw 10 and the feeding section 21 of the slow screw 20; the discharge port 402 is located below the conveying section 13 of the fast screw 10 and the conveying section 23 of the slow screw 20. In addition, the two screws have some structural differences. The difference is reflected in that, first, the two screws are respectively the fast screw 10 and the slow screw 20, which are driven by different power devices. When the fast screw 10 and the slow screw 20 rotate at different speeds, the plasticizing elements of the fast screw 10 and the slow screw 20 are partially engaged, so that the plasticizing elements of the plasticizing section (12, 22) can have strong mixing and stirring capabilities, thereby improving the mixing and plasticizing capabilities of the rubber extruder. The second difference is that the number of dumbbell parts on each mounting part 121 of the plasticizing section 12 of the fast screw 10 is less than the number of dumbbell parts on each mounting part 221 of the plasticizing section 22 of the slow screw 20. Preferably, the ratio of the number of dumbbell parts on each mounting part 121 of the plasticizing section 12 of the fast screw 10 to the number of dumbbell parts on each mounting part 221 of the plasticizing section 22 of the slow screw 20 is 1:2, 1:3 or 1:4. By adjusting the shearing efficiency of the dumbbell parts on the rubber material through the different rotation speeds of the two screws and the different settings of the number of dumbbell parts, the rubber material inside the barrel is subjected to two different degrees of shearing, so as to achieve the purpose of adjusting and improving the shearing effect of the rubber material, so that the plasticizing section can have stronger mixing and stirring capabilities, thereby improving the mixing and plasticizing capabilities of the rubber extruder on the rubber material.

[0038] The third difference is that see Figure 8 and 9 The feeding section 11 of the fast screw 10 and the feeding section 21 of the slow screw 20 are provided with conveying threads with opposite thread directions and meshing with each other, and the conveying section 13 of the fast screw 10 and the conveying section 23 of the slow screw 20 are provided with conveying threads with opposite thread directions and meshing with each other, thereby improving the conveying capacity and conveying stability.

[0039] The above description is a detailed description of the preferred feasible embodiments of the present invention, but the embodiments are not intended to limit the scope of the patent application of the present invention. All equivalent changes or modified changes completed under the technical spirit suggested by the present invention should fall within the patent scope covered by the present invention.

Claims

1. A rubber extruder screw, characterized in that: The screw comprises a feeding section, a plasticizing section and a conveying section which are arranged in sequence; the outer walls of the feeding section and the conveying section are both provided with conveying threads; the plasticizing section is a cylindrical structure, and the outer wall of the plasticizing section is provided with a plasticizing element; the plasticizing element comprises a mounting portion and a dumbbell portion, and the mounting portion is an annular body arranged at intervals on the outer wall of the plasticizing section; a plurality of dumbbell portions are fixed on the annular outer wall of each mounting portion, and the dumbbell portion comprises a columnar rod and two spheres, the columnar rod is fixed on the mounting portion, and the two spheres are respectively located at both ends of the columnar rod.

2. The rubber extruder screw according to claim 1, characterized in that: The middle part of the columnar rod is fixed on the mounting part at an angle, and the dumbbell parts on adjacent mounting parts are installed in a staggered manner, so that when viewed along the length direction of the screw rod, all the dumbbell parts are arranged in a spiral shape.

3. The rubber extruder screw according to claim 2, characterized in that: The angle between the central axis of the columnar rod and the central axis of the screw is 8-12°.

4. A rubber extruder screw according to claim 2 or 3, characterized in that: The columnar rod is a cylindrical rod, the diameter of the cylindrical rod is 1 / 9 to 1 / 7 of the working diameter of the outer surface of the plasticizing section, the diameter of the sphere is 1 / 6 to 1 / 4 of the working diameter of the outer surface of the plasticizing section, and the center distance of the spheres at both ends of the same cylindrical rod is 3 / 8 to 5 / 8 of the working diameter of the outer surface of the plasticizing section.

5. A rubber extruder screw according to claim 2 or 3, characterized in that: The distance between the columnar rod and the plasticizing section is 1 / 32 to 3 / 32 of the working diameter of the outer surface of the plasticizing section. The mounting parts are arranged at equal intervals in the plasticizing section, and the distance between adjacent mounting parts is 7 / 10 to 1 of the working diameter of the outer surface of the plasticizing section. The number of dumbbell parts on each mounting part on the same screw is the same.

6. A rubber extruder screw according to claim 1, characterized in that: The length ratio of the feeding section, the plasticizing section and the conveying section is 1:1.5 to 2.5:

1.

7. A rubber extruder plasticizing device, characterized in that: The rubber extruder screw according to any one of claims 1 to 5 comprises a barrel, wherein one or two horizontally arranged screws are arranged in the barrel, both ends of the screws are rotatably connected to the bearing seats on the outer side of the barrel end through bearings, and one end of each screw is driven to rotate by a power device.

8. A rubber extruder plasticizing device according to claim 7, characterized in that: When two screws are arranged in the barrel, the two screws are respectively a fast screw and a slow screw, and are driven by different power devices. The feeding sections, plasticizing sections and conveying sections of the two screws are aligned respectively, and the mounting parts on the plasticizing section of the fast screw and the mounting parts on the plasticizing section of the slow screw are aligned one by one, and the total number is the same. The number of dumbbell parts on each mounting part on the plasticizing section of the fast screw is less than the number of dumbbell parts on each mounting part on the plasticizing section of the slow screw; a feed port is arranged on one side of the top of the barrel, and a discharge port is arranged on one side of the bottom, and the feed port is located above the feeding section of the fast screw and the feeding section of the slow screw; the discharge port is located below the conveying section of the fast screw and the conveying section of the slow screw.

9. A rubber extruder plasticizing device according to claim 8, characterized in that: The ratio of the number of dumbbell parts on each mounting part on the fast screw plasticizing section to the number of dumbbell parts on each mounting part on the slow screw plasticizing section is 1:2, 1:3 or 1:

4.

10. A rubber extruder plasticizing device according to claim 8, characterized in that: The feeding section of the fast screw and the feeding section of the slow screw are provided with conveying threads with opposite thread directions and meshing with each other, and the conveying section of the fast screw and the conveying section of the slow screw are provided with conveying threads with opposite thread directions and meshing with each other.

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