Extruder for cable processing and method of processing

Abstract

The application provides an extruder and a processing method for cable processing. The extruder comprises a screw extruder and an extrusion die head. The extrusion die head is connected to the discharge port of the screw extruder. The extrusion die head comprises a front die cavity, a rear die cavity, a central tube, a rotating cavity and a rotating driving part. The front die cavity, the rotating cavity and the rear die cavity are sequentially connected. The first channel is arranged in the front die cavity. The second channel is arranged in the rotating cavity. The rear die cavity is provided with a groove. The first channel, the second channel and the groove are sequentially connected to form an extrusion cavity. The rotating cavity is rotatably connected to the front die cavity and the rear die cavity. The central tube is coaxially arranged in the extrusion cavity. The rotating driving part is fixedly connected to the rear die cavity. The driving end of the rotating driving part is in transmission connection with the surface of the rotating cavity. The rotating driving part can drive the rotating cavity to rotate. The processing method drives the rotating cavity to rotate through the rotating driving part, so that the molten material in the extrusion die head is circumferentially stirred and rotated, and the dispersivity of the molten material in the extrusion die head is improved.

Description

Technical Field

[0001] This invention relates to the field of cable processing equipment technology, and in particular to an extruder and processing method for cable processing. Background Technology

[0002] A cable includes at least a wire and an insulation layer and a protective layer covering the outer surface of the wire. In the prior art, the insulation layer and the protective layer of a cable are generally processed by co-extrusion of the wire and the insulation layer material or the protective layer material. Specifically, the insulation layer material or the protective layer material is heated and melted and then extruded into a die with an annular cavity. The wire is allowed to pass through the middle of the annular cavity die. After the wire passes through, it is combined with the outer jacket layer extruded from the annular extrusion port, thereby completing the cable processing.

[0003] However, in the above scheme, the molten material extruded from the extruder flows into the annular cavity under pressure and fills the die cavity. Due to the shape limitation of the annular cavity and the influence of the connection position between the extruder outlet and the cavity, the dispersion and filling of the molten material extruded into the die cavity are insufficient. This leads to defects on the surface of the insulation and protective layers of the extruded cable, such as bubbles, gaps, and interfaces caused by uneven distribution during the extrusion process. These defects pose safety hazards to the quality of the cable.

[0004] Improving the dispersion and filling properties of molten material within the extrusion die has become one of the urgent technical problems to be solved. Summary of the Invention

[0005] In view of this, the present invention proposes an extruder and processing method for cable processing, aiming to improve the dispersion of molten material in the extrusion die by improving the structure of the extruder.

[0006] The technical solution of this invention is implemented as follows: This invention provides an extruder for cable processing, including a screw extruder and an extrusion die. The extrusion die is connected and installed at the discharge port of the screw extruder. The extrusion die includes a front die cavity, a rear die cavity, a central tube, a rotating cavity, and a rotating drive component. The front die cavity, the rotating cavity, and the rear die cavity are connected in sequence. The front die cavity has a first channel, the rotating cavity has a second channel, and the surface of the rear die cavity has a groove. The first channel, the second channel, and the groove are connected in sequence to form an extrusion cavity. The side of the rear die cavity has a feed port, which is connected to the groove. The end of the first channel away from the rotating cavity opens to be the discharge port. The rotating cavity is rotatably connected to both the front die cavity and the rear die cavity. The central tube is coaxially disposed within the extrusion cavity. The end of the central tube near the rear die cavity passes through the rear die cavity and is fixedly connected to it. The end of the central tube near the front die cavity passes through the discharge port and forms an annular outlet with a gap between it and the discharge port. The rotating drive component is fixedly connected to the rear die cavity. The driving end of the rotating drive component is connected to the surface of the rotating cavity through a transmission connection. The rotating drive component can drive the rotating cavity to rotate.

[0007] In some embodiments, the inner surface of the second channel is provided with helical protrusions along the axial direction.

[0008] In some embodiments, the first channel, the second channel, and the groove are all cylindrical, and the first channel, the second channel, and the groove are coaxially arranged and have the same inner diameter.

[0009] In some embodiments, a connecting plate is also included, wherein both the front mold cavity and the rear mold cavity are fixedly mounted on the surface of the connecting plate.

[0010] In some embodiments, the rotating cavity has a first chamfered surface along its outer circumference at one end near the front mold cavity, and a second chamfered surface along its circumference on the inner side of the first channel, with the first chamfered surface and the second chamfered surface slidingly engaged.

[0011] In some embodiments, a first thrust bearing is also included, wherein the inner ring of the first thrust bearing is coaxially embedded in a first chamfered surface, and the outer ring of the first thrust bearing is coaxially embedded in a second chamfered surface.

[0012] In some embodiments, the rotating cavity has a third chamfered surface along its outer circumference at one end near the rear mold cavity, and a fourth chamfered surface along its circumference is provided on the inner side of the groove, with the third chamfered surface and the fourth chamfered surface slidingly engaged.

[0013] In some embodiments, a second thrust bearing is also included, the inner ring of which is coaxially embedded in a third chamfered surface, and the outer ring of which is coaxially embedded in a fourth chamfered surface.

[0014] In some embodiments, a combustion nozzle is also included, which is fixedly mounted on the connecting plate, with the nozzle's nozzle outlet facing the outer surface of the rotating cavity.

[0015] In another aspect, the present invention provides a processing method for an extruder based on the above-mentioned cable processing, comprising the following steps: driving the wire to be conveyed at a constant speed to one side of the discharge port in the central tube; the screw extruder extrudes molten material into the extrusion cavity; rotating the drive component drives the rotating cavity to rotate and circumferentially stirs the molten material located in the rotating cavity; the molten material is extruded from the annular outlet and then covers the surface of the wire; after cooling, a cable is obtained.

[0016] Optionally, in the above processing method, the combustion nozzle can be turned on and the rotating cavity can be heated during the rotation of the rotating cavity.

[0017] The cable processing extruder and processing method of the present invention have the following advantages over the prior art:

[0018] This invention improves the internal structure of the extruder die by setting a rotating cavity in the middle section of the extrusion cavity that can rotate around the axis. When the molten material extruded from the screw extruder flows through the second channel of the rotating cavity, the different layers of fluid along the radial direction are rotated and stirred by the intermolecular forces under the rotation of the rotating cavity, thereby improving the uniformity of the dispersion of the molten material in the extrusion die. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention 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 the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is an isometric view of the extruder used for cable processing according to the present invention;

[0021] Figure 2 for Figure 1 Exploded view;

[0022] Figure 3 This is an isometric view of the extrusion die portion in the extruder used for cable processing according to the present invention.

[0023] Figure 4 for Figure 3 Exploded view;

[0024] Figure 5 for Figure 3 Cross-sectional view;

[0025] Figure 6 for Figure 3 Cross-sectional view under localized explosion conditions.

[0026] In the diagram: 1-Screw extruder, 2-Extrusion die head, 3-Connecting plate, 4-First thrust bearing, 5-Second thrust bearing, 6-Combustion nozzle, 21-Front die cavity, 22-Rear die cavity, 23-Center tube, 24-Rotating cavity, 25-Rotating drive component, 211-First channel, 2111-Second chamfered surface, 212-Discharge port, 221-Groove, 2211-Fourth chamfered surface, 222-Feed port, 241-Second channel, 242-First chamfered surface, 2411-Spiral protrusion, 243-Third chamfered surface. Detailed Implementation

[0027] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0028] It should be noted that when a component is referred to as being "fixed to" or "set on" another component, it can be directly on or indirectly on that other component. When a component is referred to as being "connected to" another component, it can be directly connected to or indirectly connected to that other component.

[0029] It should be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0030] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0031] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the embodiments of this invention pertain. If any definition stated in this section is contrary to or otherwise inconsistent with a definition stated in a patent, patent application, published patent application, or other publication incorporated herein by reference, the definitions listed here shall prevail over those incorporated herein by reference.

[0032] like Figure 1 As shown, combined with Figure 2-6 The cable processing extruder of the present invention includes a screw extruder 1 and an extrusion die 2. The extrusion die 2 is connected and installed at the discharge port of the screw extruder 1. The extrusion die 2 includes a front die cavity 21, a rear die cavity 22, a central tube 23, a rotating cavity 24, and a rotation drive component 25. The front die cavity 21, the rotating cavity 24, and the rear die cavity 22 are connected in sequence. A cylindrical first channel 211 is provided through the front die cavity 21, and a cylindrical second channel 241 is provided through the rotating cavity 24. A cylindrical groove 221 is provided on the surface of the rear die cavity 22. The first channel 211, the second channel 241, and the groove 221 are connected in sequence to form an extrusion cavity. A feed port 22 is provided on the side of the rear die cavity 22. 2. The feed inlet 222 is connected to the groove 221. The end of the first channel 211 away from the rotating cavity 24 is opened as the discharge port 212. The rotating cavity 24 is rotatably connected to the front mold cavity 21 and the rear mold cavity 22 respectively. The central tube 23 is coaxially disposed in the extrusion cavity. The end of the central tube 23 near the rear mold cavity 22 passes through the rear mold cavity 22 and is fixedly connected to the rear mold cavity 22. The end of the central tube 23 near the front mold cavity 21 passes through the discharge port 212 and forms an annular outlet with the discharge port 212 at intervals. The rotating drive component 25 is fixedly connected to the rear mold cavity 22. The driving end of the rotating drive component 25 is connected to the surface of the rotating cavity 24 through a transmission connection. The rotating drive component 25 can drive the rotating cavity 24 to rotate.

[0033] In the above embodiments, the central tube 23 is coaxial with the extrusion cavity formed by connecting the front die cavity 21, the rotating cavity 24 and the rear die cavity 22. An annular extrusion channel is formed between the outer wall of the central tube 23 and the inner wall of the extrusion cavity. The feed port 222 introduces the molten material in the screw extruder 1 into the annular extrusion channel. Under pressure, the molten material disperses and fills the space in the groove 221, and gradually flows to the second channel 241 and the first channel 211 in sequence. In conventional processes, this flow process is driven by the extrusion pressure of the screw extruder 1. The molten material is a fluid and has the tendency to flow out of the annular extrusion channel along the shortest channel. Therefore, it is easy for the molten fluid to flow unevenly in the annular extrusion channel. For example, the molten material near the feed port 222 is not easy to flow to the side away from the feed port 222. The rotating cavity 24 is driven to rotate around its axis by the rotating drive component 25. During the rotation, the molten material flowing through the second channel 241 is rotated and mixed in the second channel 241 under the rotation of the inner wall of the second channel 241, which promotes the uniform mixing and dispersion of the molten material in the second channel 241.

[0034] In some embodiments, the inner surface of the second channel 241 is provided with a helical protrusion 2411 along the axial direction.

[0035] In the above embodiments, when the rotating cavity 24 rotates, the driving effect on the molten material located in the second channel 241 is achieved through the viscosity between the inner wall of the second channel 241 and the molten material. This stirring effect is relatively limited, and it is difficult to form a stirring effect between the layers of molten material in the radial direction. In order to overcome this problem, a screw-shaped spiral protrusion 2411 is provided on the inner surface of the second channel 241. The spiral protrusion 2411 is arranged along the axial direction of the second channel 241. On the one hand, the spiral protrusion 2411 can improve the material exchange between layers and promote stirring. On the other hand, the screw-shaped spiral protrusion 2411 can play a pushing role along the axial direction when stirring, further strengthening the material exchange and stirring of the molten material at the axial position and the outer position.

[0036] In some embodiments, the height of the spiral protrusion 2411 is preferably 1 / 3 to 2 / 3 of the distance between the inner wall of the second channel 241 and the outer wall of the central tube 23.

[0037] The spiral protrusions 2411 of the above-mentioned height can achieve better stirring effect, and at the same time, the molten material is less likely to adhere to the spiral protrusions 2411 and block the channel.

[0038] In some embodiments, the first channel 211, the second channel 241, and the groove 221 are all cylindrical, and the first channel 211, the second channel 241, and the groove 221 are coaxially arranged and have the same inner diameter.

[0039] In the above embodiments, when the inner diameter is the same, the resistance is smaller when the material flows from the groove 221 into the first channel 211.

[0040] In some embodiments, a connecting plate 3 is also included, wherein the front mold cavity 21 and the rear mold cavity 22 are both fixedly mounted on the surface of the connecting plate 3.

[0041] In the above embodiments, a connecting plate 3 is used to connect the front mold cavity 21, the rear mold cavity 22 and the rotating cavity 24. Specifically, the three are connected to the connecting plate 3 by bolts. By using the connecting plate 3 to connect the three, the front mold cavity 21, the rear mold cavity 22 and the rotating cavity 24 can be disassembled, replaced and maintained.

[0042] In some embodiments, the rotating cavity 24 is provided with a first chamfered surface 242 along the outer periphery at one end near the front mold cavity 21, and a second chamfered surface 2111 is provided along the periphery on the inner side of the first channel 211, and the first chamfered surface 242 and the second chamfered surface 2111 are slidably engaged.

[0043] In the above embodiments, since the rotating cavity 24 and the front mold cavity 21 are rotatably connected, and the extrusion die 2 needs to withstand a large pressure, it is necessary to maximize the dynamic sealing effect at the rotating connection during rotation. Chamfered surfaces are provided on the outer periphery of the rotating cavity 24 and the inner periphery of the first channel 211 of the front mold cavity 21. The chamfered surfaces are conical surfaces. On the one hand, this can increase the contact area at the sliding fit and improve the sealing effect. On the other hand, the conical surfaces also have a positioning and guiding function, which can keep the axial alignment between the first channel 211 and the second channel 241.

[0044] In some embodiments, the system further includes a first thrust bearing 4, the inner ring of which is coaxially embedded in the first chamfered surface 242, and the outer ring of which is coaxially embedded in the second chamfered surface 2111.

[0045] In the above embodiments, when the surfaces are in contact, the friction is relatively large. In order to avoid the problem of large friction and severe wear caused by direct contact friction of materials, a first thrust bearing 4 is used to connect the two chamfered surfaces. Specifically, the first thrust bearing 4 is conical, with a conical outer ring surface and a conical inner ring surface. The two conical surfaces are used to cooperate and connect with the first chamfered surface 242 and the second chamfered surface 2111.

[0046] In some embodiments, the first thrust bearing 4 may be a sealed thrust bearing.

[0047] In some embodiments, in order to achieve a mating connection with the first thrust bearing 4, corresponding positioning grooves are provided circumferentially on the surfaces of the first chamfered surface 242 and the second chamfered surface 2111, respectively, for embedding the inner ring and outer ring of the first thrust bearing 4.

[0048] In some embodiments, the rotating cavity 24 is provided with a third chamfered surface 243 along the outer circumference at one end near the rear mold cavity 22, and a fourth chamfered surface 2211 is provided along the circumference on the inner side of the groove 221, and the third chamfered surface 243 and the fourth chamfered surface 2211 are slidably engaged.

[0049] Similarly, in order to improve the dynamic sealing effect and at the same time have a certain centering effect, the rotating cavity 24 and the rear mold cavity 22 are also fitted with a tapered chamfered surface for sliding fit.

[0050] In some embodiments, a second thrust bearing 5 is further included, the inner ring of which is coaxially embedded in the third chamfered surface 243, and the outer ring of which is coaxially embedded in the fourth chamfered surface 2211.

[0051] In the above embodiments, the installation method and structure of the second thrust bearing 5 are the same as those of the first thrust bearing 4. The second thrust bearing 5 is used as a rotating connector to avoid direct sliding contact between the third chamfered surface 243 and the fourth chamfered surface 2211, thereby reducing sliding resistance.

[0052] In some embodiments, the surfaces of the third chamfered surface 243 and the fourth chamfered surface 2211 are also provided with annular grooves for fitting the inner and outer rings of the second thrust bearing 5, and are connected by embedding to improve sealing.

[0053] In some embodiments, the second thrust bearing 5 may be a sealed thrust bearing.

[0054] In some embodiments, a combustion nozzle 6 is also included, which is fixedly mounted on the connecting plate 3, and the nozzle 6 is positioned facing the outer surface of the rotating cavity 24.

[0055] In the above embodiments, since the rotating cavity 24 needs to maintain rotation, the rotation process can easily lead to crystallization in the molten material. In order to avoid this problem and improve the stirring effect during the rotation process, the combustion nozzle 6 is used to heat the rotating cavity 24, thereby heating the molten material inside and improving the fluidity of the molten material.

[0056] In some embodiments, an annular protrusion structure is provided on the inner surface of the first channel 211 near the second channel 241, and the annular protrusion structure protrudes from the inner wall of the first channel 211.

[0057] In the above embodiments, the annular protrusion structure is provided to block and disturb the material layer on the side of the molten material flowing into the first channel 211 near the inner wall of the first channel 211, which plays a role in forcibly pushing and stirring the flow. Unlike the spiral stirring effect of the spiral protrusion 2411, when the molten material flows through the annular protrusion structure, the flow channel becomes smaller abruptly, the internal pressure of the fluid increases, and the flow velocity increases. At the same time, this process is conducive to eliminating structures such as bubbles and air gaps in the fluid, further improving the surface and internal quality of the extruded material, and helping to reduce internal defects.

[0058] In some embodiments, a second annular protrusion is integrally formed on the outer surface of the central tube 23 and on the side of the annular protrusion structure near the discharge port 212. The second annular protrusion and the annular protrusion structure form a maze-like structure.

[0059] In the above embodiments, the second annular protrusion, in conjunction with the annular protrusion structure, can further compress and stir the molten material, promoting the elimination of defects such as internal air bubbles or gaps, while also enhancing the stirring effect.

[0060] In some embodiments, the side of the second annular protrusion near the discharge port 212 smoothly transitions with the outer surface of the central tube 23.

[0061] In the above embodiments, the smooth transition of the second annular protrusion facilitates the filling of the extruded molten material into the first channel 211, avoiding insufficient filling.

[0062] In some embodiments, the processing method of the extruder in the above embodiments includes:

[0063] The drive wire is uniformly conveyed to the discharge port 212 side in the central tube 23. The screw extruder 1 extrudes the molten material into the groove 221. Under pressure, the molten material gradually flows through the second channel 241 and the first channel 211 and is finally extruded from the discharge port 212. During the flow through the second channel 241, the rotating drive component 25 is turned on, which drives the rotating cavity 24 to rotate, thereby rotating and stirring the molten material flowing through the second channel 241. The extruded molten material is sleeved on the outside of the wire and hardened after stretching and cooling to obtain the cable.

[0064] In other embodiments, the combustion nozzle 6 can be turned on to heat the rotating cavity 24, so that the internal temperature of the rotating cavity 24 is maintained within the target temperature range, and the molten material has good fluidity.

[0065] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A cable processing extruder comprising a screw extruder (1) and an extrusion die (2) which is communicatively mounted at a discharge opening of the screw extruder (1), characterized in that The extrusion die (2) comprises a front die cavity (21), a rear die cavity (22), a center tube (23), a rotating cavity (24) and a rotating driving part (25), the front die cavity (21), the rotating cavity (24) and the rear die cavity (22) are sequentially connected, the first channel (211) is arranged in the front die cavity (21), the second channel (241) is arranged in the rotating cavity (24), the surface of the rear die cavity (22) is provided with a groove (221), the first channel (211), the second channel (241) and the groove (221) are sequentially communicated to form an extrusion cavity, the side of the rear die cavity (22) is provided with a feeding port (222), the feeding port (222) is communicated with the groove (221), the end of the first channel (211) away from the rotating cavity (24) is an outlet (212), the rotating cavity (24) is rotatably connected with the front die cavity (21) and the rear die cavity (22), the center tube (23) is coaxially and penetratingly arranged in the extrusion cavity, the end of the center tube (23) close to the rear die cavity (22) penetrates through the rear die cavity (22) and is fixedly connected with the rear die cavity (22), the end of the center tube (23) close to the front die cavity (21) penetrates through the outlet (212) and forms an annular outlet with the outlet (212), the rotating driving part (25) is fixedly connected with the rear die cavity (22), the driving end of the rotating driving part (25) is in transmission connection with the surface of the rotating cavity (24), the rotating driving part (25) can drive the rotating cavity (24) to rotate, the inner surface of the second channel (241) is provided with a spiral protrusion (2411) along the axial direction, the inner surface of the first channel (211) is provided with an annular protrusion structure on the side close to the second channel (241), the annular protrusion structure protrudes from the inner wall of the first channel (211), the outer surface of the center tube (23) is integrally and protrusively provided with a second annular protrusion on the side close to the outlet (212) of the annular protrusion structure, and the second annular protrusion forms a labyrinth structure with the annular protrusion structure.

2. A cable processing extruder as claimed in claim 1, characterized in that The inner surface of the second channel (241) is provided with a spiral protrusion (2411) along the axial direction.

3. A cable processing extruder as claimed in claim 1, characterized in that The front die cavity (21) and the rear die cavity (22) are fixedly installed on the surface of the connecting plate (3).

4. A cable processing extruder as claimed in claim 3, characterized in that The end of the rotating cavity (24) close to the front die cavity (21) is provided with a first chamfer surface (242) along the outer periphery, the inner side of the first channel (211) is provided with a second chamfer surface (2111) along the periphery, and the first chamfer surface (242) is in sliding connection with the second chamfer surface (2111).

5. A cable processing extruder as claimed in claim 4, characterized in that The inner ring of the first thrust bearing (4) is coaxially embedded on the first chamfer surface (242), and the outer ring of the first thrust bearing (4) is coaxially embedded on the second chamfer surface (2111).

6. A cable processing extruder as claimed in claim 3, characterized in that The end of the rotating cavity (24) close to the rear die cavity (22) is provided with a third chamfer surface (243) along the outer periphery, the inner side of the groove (221) is provided with a fourth chamfer surface (2211) along the periphery, and the third chamfer surface (243) is in sliding connection with the fourth chamfer surface (2211).

7. A cable processing extruder as claimed in claim 6, characterized in that The second thrust bearing (5) is coaxially embedded on the third chamfer surface (243) and the outer ring of the second thrust bearing (5) is coaxially embedded on the fourth chamfer surface (2211).

8. A cable processing extruder as claimed in claim 3, characterized in that The combustion nozzle (6) is fixedly installed on the connecting plate (3), and the jet port of the combustion nozzle (6) is arranged opposite to the outer surface of the rotating cavity (24).

9. A process for the processing of a cable-processed extruder according to any one of claims 1 to 8, characterized in that The method comprises the following steps: driving the wire to move uniformly in the center tube (23) to the side of the discharge port (212), extruding the molten material into the extrusion cavity by the screw extruder (1), driving the rotating cavity (24) to rotate by the rotating driving member (25) and stirring the molten material in the rotating cavity (24) in the circumferential direction, and extruding the molten material from the annular outlet to coat the surface of the wire, so that the cable is obtained after cooling.

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