screw mechanism

Abstract

The utility model discloses a screw mechanism, including machine cylinder and install in the screw of machine cylinder. Screw includes screw head and screw tail, and screw has feeding section, compression section and metering section in proper order from screw head to screw tail. Metering section has multithread structure, and multithread structure has at least two screw edges, and has screw groove between two adjacent screw edges, and multiple screw grooves are evenly distributed on the same section. The filling is transported through the compression section, and enters one of the multiple screw grooves of the metering section in proper order, so that the filling can be evenly distributed in the multiple screw grooves of the metering section, and the screw is formed in multiple directions and is continuously extruded, avoiding unilateral extrusion in the same direction, reducing the abrasion caused by the excessive contact between the unilateral screw edge of the screw and the machine cylinder, and realizing high-precision, long-life operation in the extrusion process.

Description

Technical Field

[0001] This utility model relates to the field of screw extruder technology, and specifically to a screw mechanism. Background Technology

[0002] Extrusion molding equipment is widely used in polymer processing, with the screw considered a core component determining the precision of the extrusion process. In a single-screw extruder, polymer filler sequentially passes through the feeding section, compression section, and metering section of the screw, distributing itself within the gap between the inner wall of the barrel and the outer edge of the screw. Under ideal conditions, the filler can fully fill all the gaps between the screw channel and the barrel, wrapping the screw 360° and applying uniform circumferential pressure to keep the screw in a straight position, thus effectively avoiding excessive contact between the screw and the barrel and the resulting abnormal wear. However, in actual production, due to fluctuations or intermittent material interruptions in the upstream feeding system, the filler in the barrel cannot continuously and uniformly fill the aforementioned gaps. In this case, the distribution of the filler in the screw channel exhibits a fixed radial periodicity related to the feeding frequency, causing the filler to apply a continuous and singular extrusive force to the screw only in a specific radial direction. As the screw rotates, this asymmetrical load will cause the screw to shift to the side subjected to the force, resulting in excessive contact between the screw edge on that side and the inner wall of the barrel and accelerated wear, thereby reducing extrusion accuracy, shortening equipment life and increasing maintenance costs. Utility Model Content

[0003] The purpose of this utility model is to overcome the shortcomings of the prior art and provide a screw mechanism that effectively suppresses unilateral force and wear on the screw caused by discontinuous feeding through a uniformly distributed screw edge and screw groove structure.

[0004] This utility model proposes a screw mechanism, including a barrel and a screw installed inside the barrel; the screw includes a screw head and a screw tail, and the screw has a feeding section, a compression section and a metering section sequentially from the screw head to the screw tail; the metering section has a multi-thread structure, the multi-thread structure has at least two screw edges, and there is a screw groove between two adjacent screw edges, and the multiple screw grooves are evenly distributed on the same cross section.

[0005] In one embodiment, the surfaces of the feeding section and the compression section are provided with a single thread.

[0006] In one embodiment, the outer diameter of the threads of the feeding section, the compression section, and the metering section are the same.

[0007] In one embodiment, the thread pitch width of the feeding section and the compression section is equal.

[0008] In one embodiment, the main body of the compression section is a conical section, and the diameter of the main body near the feeding section is smaller than the diameter of the main body near the metering section.

[0009] In one embodiment, the metering segment is evenly distributed with two, three, or four spiral ridges.

[0010] In one embodiment, a feed inlet is provided on one end of the barrel near the feeding section.

[0011] The screw mechanism provided by this utility model includes a barrel and a screw installed inside the barrel. The screw includes a screw head and a screw tail, and from the screw head to the screw tail, the screw has a feeding section, a compression section, and a metering section in sequence. The metering section has a multi-threaded structure with at least two screw ridges and a screw groove between two adjacent screw ridges, with multiple screw grooves evenly distributed on the same cross section. The filler is conveyed by the compression section and sequentially enters one of the multiple screw grooves in the metering section. In this way, the filler can be evenly distributed in the multiple screw grooves of the metering section, forming a multi-directional, uniform, and continuous compression of the screw, avoiding compression in the same direction on one side, reducing wear caused by excessive contact between the screw ridges on one side of the screw and the barrel, and achieving high-precision and long-life operation in the extrusion process. Attached Figure Description

[0012] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0013] Figure 1 This is a front view of an embodiment of the screw of this utility model; Figure 2 yes Figure 1 Sectional view along line AA; Figure 3 This is a structural cross-sectional view of an embodiment of the screw mechanism of this utility model; Explanation of icon numbers:

[0014] The realization of the purpose, functional features and advantages of this utility model will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0015] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0016] It should be noted that all directional indicators (such as up, down, left, right, front, back, etc.) in this utility model embodiment are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicator will also change accordingly.

[0017] In this utility model, unless otherwise explicitly specified and limited, the terms "connection," "fixing," etc., should be interpreted broadly. For example, "fixing" can mean a fixed connection, a detachable connection, or an integral part; it can mean a mechanical connection or an electrical connection; it can mean a direct connection or an indirect connection through an intermediate medium; it can mean the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0018] Furthermore, in this utility model, descriptions involving "first," "second," etc., are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, features defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the word "and / or" throughout the text means including three parallel solutions; taking "A and / or B" as an example, it includes solution A, solution B, or a solution that simultaneously satisfies A and B. Furthermore, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this utility model.

[0019] Extrusion molding equipment is widely used in polymer processing, with the screw considered a core component determining the precision of the extrusion process. In a single-screw extruder, polymer filler sequentially passes through the feeding section, compression section, and metering section of the screw, distributing itself within the gap between the inner wall of the barrel and the outer edge of the screw. Under ideal conditions, the filler can fully fill all the gaps between the screw channel and the barrel, wrapping the screw 360° and applying uniform circumferential pressure to keep the screw in a straight position, thus effectively avoiding excessive contact between the screw and the barrel and the resulting abnormal wear. However, in actual production, due to fluctuations or intermittent material interruptions in the upstream feeding system, the filler in the barrel cannot continuously and uniformly fill the aforementioned gaps. In this case, the distribution of the filler in the screw channel exhibits a fixed radial periodicity related to the feeding frequency, causing the filler to apply a continuous and singular extrusive force to the screw only in a specific radial direction. As the screw rotates, this asymmetrical load will cause the screw to shift to the side subjected to the force, resulting in excessive contact between the screw edge on that side and the inner wall of the barrel and accelerated wear, thereby reducing extrusion accuracy, shortening equipment life and increasing maintenance costs.

[0020] This utility model proposes a screw mechanism. Please refer to... Figures 1 to 3 The device includes a barrel 2 and a screw 1 installed inside the barrel 2. The screw 1 includes a screw head 11 and a screw tail 12. The screw 1 has a feeding section 13, a compression section 14 and a metering section 15 sequentially from the screw head 11 to the screw tail 12. The metering section 23 has a multi-thread structure with at least two screw ridges 131 and a screw groove 132 between two adjacent screw ridges 131. The multiple screw grooves 132 are evenly distributed on the same cross section.

[0021] In this embodiment, the screw mechanism mainly includes a barrel 2 and a screw 1 coaxially mounted inside the barrel 2 and rotatable about its own axis. The screw 1, along its axial direction from upstream to downstream, includes a screw head 11, a feeding section 13, a compression section 14, a metering section 15, and a screw tail 12. The screw head 11 is located at the upstream end and is used for transmission connection with a drive device (such as a motor and gearbox, not shown in the figure) to transmit rotational power to the entire screw 1. The screw tail 12 is located at the downstream end and is used for connection with a downstream mold or auxiliary device. The metering section 15 is located downstream of the compression section 14, and its outer surface is provided with a multi-threaded structure. This multi-threaded structure has at least two threaded edges 131, which are evenly distributed circumferentially on the same cross-section, such that a corresponding threaded groove 132 is formed between two adjacent threaded edges 131. In this embodiment, the metering section 15 can be flexibly configured with a double-thread, triple-thread, or quadruple-thread structure according to the characteristics of the extruded material and the production requirements. That is, the number of screw ridges 131 and screw grooves 132 are two, three, or four, respectively, and the depth, width, and lead of each screw groove 132 can be kept consistent to achieve uniform distribution, balanced plasticization, and stable metering of the material in the metering section 15. The outer diameter of the multi-thread structure is the same as the outer diameter of the threads in the feeding section 13 and the compression section 14, ensuring that the overall outer contour of the screw 1 is continuous and consistent, which facilitates the processing and assembly of the barrel 2 and reduces the risk of material retention and degradation in the transition zone.

[0022] Further, please refer to Figure 1 The surfaces of the feeding section 13 and the compression section 14 are provided with single threads.

[0023] Specifically, the outer surfaces of the feeding section 13 and the compression section 14 of the screw 1 are provided with a single thread. The outer diameter of the screw thread is consistent throughout the feeding section 13 and the compression section 14, and forms a uniform gap with the inner wall of the barrel 2, so as to ensure that the material can be preheated and initially compacted at the same time during the conveying process.

[0024] Further, please refer to Figure 1 The thread pitch widths of the feeding section 13 and the compression section 14 are equal.

[0025] Specifically, the thread pitch width (i.e., thread width) of the feeding section 13 and the compression section 14 is equal, so that the material maintains a stable axial propulsion speed during the conveying process, reducing the risk of pressure fluctuations and melt rupture caused by sudden changes in thread pitch.

[0026] Further, please refer to Figure 1 The main body of the compression section 14 is a conical section, and the diameter of the main body near the feeding section 13 is smaller than the diameter of the main body near the metering section 15.

[0027] Specifically, the main body of the compression section 14 is constructed as a conical section, with its small end close to the feeding section 13 and its large end close to the metering section 15. The diameter of the small end is slightly smaller than that of the large end, so that a gradually converging compression chamber is formed between the barrel wall of the barrel 2 and the screw 1 in the axial direction, so as to perform progressive compression and degassing on the material, thereby improving the melt density and plasticization uniformity.

[0028] Further, please refer to Figure 3 The barrel 2 has a feed inlet 2a at one end near the feeding section 13.

[0029] Specifically, a feed inlet 2a is provided on the cylinder wall near the upstream end (i.e. the end near the feeding section 13) of the cylinder 2, which is used to connect with the upstream feeding device (not shown in the figure) to ensure that the material can enter the cylinder 2 continuously or intermittently.

[0030] In one embodiment, when the screw 1 rotates inside the barrel 2, the material enters the feeding section 13 from the feed inlet 2a, is first conveyed and initially compacted by a single thread; then it enters the compression section 14, where it is further compressed, melted, and degassed in the conical cavity; finally, it enters the metering section 15, where it is evenly distributed into each screw groove 132 under the action of the multi-threaded structure, achieving circumferential balanced filling. Because the metering section 15 has multiple symmetrically distributed screw grooves 132 in the same cross-section, the radial pressure exerted by the material on the screw 1 is dispersed in multiple directions, forming a multi-point, evenly distributed support force. This effectively counteracts the unilateral load caused by discontinuous upstream feeding, significantly reducing the risk of the screw 1 shifting to the stressed side and mitigating excessive contact and wear between the screw edge 131 on that side and the inner wall of the barrel 2. Compared with the traditional single-threaded metering section, this invention can reduce the unilateral wear rate of the screw, extend its service life, and simultaneously improve extrusion pressure stability and product dimensional accuracy.

[0031] In the description of this specification, references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0032] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention without departing from the principles and spirit of the present invention.

Claims

1. A screw mechanism, characterized in that, The device includes a barrel (2) and a screw (1) installed inside the barrel (2); the screw (1) includes a screw head (11) and a screw tail (12), and the screw (1) has a feeding section (13), a compression section (14) and a metering section (15) sequentially from the screw head (11) to the screw tail (12); the metering section (15) has a multi-thread structure, the multi-thread structure has at least two screw edges (151), and there is a screw groove (152) between two adjacent screw edges (151), and the multiple screw grooves (152) are evenly distributed on the same cross section.

2. The screw mechanism as described in claim 1, characterized in that, The surfaces of the feeding section (13) and the compression section (14) are provided with single threads.

3. The screw mechanism as described in claim 2, characterized in that, The feed section (13), the compression section (14), and the metering section (15) have the same thread outer diameter.

4. The screw mechanism as described in claim 2, characterized in that, The thread pitch widths of the feeding section (13) and the compression section (14) are equal.

5. The screw mechanism as described in claim 1, characterized in that, The main body of the compression section (14) is a conical section, and the diameter of the main body near the feeding section (13) is smaller than the diameter of the main body near the metering section (15).

6. The screw mechanism as described in claim 1, characterized in that, The metering segment (15) has two, three or four spiral ridges (151) evenly distributed.

7. The screw mechanism as described in claim 4, characterized in that, The barrel (2) has a feed inlet (2a) at one end near the feeding section (13).

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