A polyolefin insulated flexible cable extruder

Abstract

This invention relates to the field of plastic molding technology, specifically disclosing a polyolefin insulated flexible cable extruder, including a frame and extrusion molding components. The die head body has an inner lining channel inside, with a flexible metal thin-walled sleeve fitted in the middle section of the inner lining channel. The two ends of the sleeve are fixed and rolled to form deformable sections. The outer side is divided into multiple independent pressure regulating chambers by a grid plate, and corresponding media injection ports are provided. One end of the inner lining channel is provided with a diverter consisting of an outer sleeve and a cable inner core tube, forming a first and second annular diverter channels that are interconnected. This solution adjusts the pressure inside the chambers through the injection ports, allowing the flexible thin-walled sleeve to elastically displace between the melt pressure and the media pressure, thus constructing an adaptive pressure-stabilizing regulating channel. This effectively suppresses melt pressure pulsation and significantly improves the dimensional accuracy, concentricity, and surface smoothness of the flexible cable insulation layer, solving the technical defects of traditional rigid channels that are difficult to micro-control online.

Description

Technical Field

[0001] This invention relates to the field of plastic molding technology, and more particularly to a polyolefin insulated flexible cable extruder. Background Technology

[0002] Polyolefins (such as polyethylene and polypropylene) are widely used in the manufacture of insulation and sheath layers of flexible cables due to their excellent electrical insulation properties, chemical corrosion resistance and good flexibility. In the production process of flexible cables, the extruder is the core equipment. Its working principle is to wrap molten polyolefin material onto the moving cable core through the die head mold, and form the finished product after cooling and shaping.

[0003] Current extruders typically employ a rigid, fixed design for their core flow channel structure and forming die. During production, they rely primarily on the constant rotational speed of the screw to establish extrusion pressure, forcing the melt to coat the cable through a die nozzle with a fixed diameter. The cable is then transported to the cooling process via a linear traction mechanism.

[0004] However, for polyolefin insulated flexible cables, due to the significant non-Newtonian fluid characteristics of their melt material (i.e., sensitivity to pressure and shear), and the fact that the finished flexible cable is extremely susceptible to deformation due to gravity and internal stress immediately after extrusion, existing rigid extrusion equipment has significant limitations. That is, existing equipment lacks an adaptive buffering mechanism for the fluctuation of melt pressure inside the flow channel, which causes the instability of the pressure during melt extrusion to be directly mapped to the unevenness of the insulation layer thickness, thereby affecting the compactness of the insulation layer and limiting the quality of the final finished cable. Summary of the Invention

[0005] The main objective of this invention is to provide a polyolefin insulated flexible cable extruder, which aims to at least solve one of the aforementioned technical problems existing in the prior art.

[0006] To achieve the above objectives, the present invention provides a polyolefin insulated flexible cable extruder, including a frame and an extrusion molding assembly disposed on the upper part of the frame. The extrusion molding assembly includes a die head body, an inner lining channel is formed inside the die head body, a flexible metal thin-walled sleeve is coaxially sleeved in the middle section of the inner lining channel, the two ends of the flexible metal thin-walled sleeve are fixedly connected to the inner lining channel, and its inner surface is rolled to form a deformable section of the inner lining channel. An annular gap is formed between the outer surface of the flexible metal thin-walled sleeve and the inner lining channel. Multiple grid plates are arrayed inside the annular gap, and the multiple grid plates divide the annular gap into multiple independent pressure regulating chambers. Several medium injection ports corresponding to and communicating with the pressure regulating chambers are also formed on the die head body.

[0007] The inner lining channel is provided with a diversion component at one end of the deformable section. The diversion component includes an outer tube closed at one end and a cable inner core tube coaxially sleeved inside the outer tube. One end of the cable inner core tube passes through the deformable section, and its outer wall surface forms a first annular diversion channel and a second annular diversion channel that are interconnected with the inner wall of the outer tube and the inner wall of the deformable section, respectively.

[0008] Furthermore, the first annular diversion channel is also provided with a diversion block sleeved on the outside of the cable inner core tube. The diversion block is conical and has a flow-blocking end face on one side. An annular gap is formed between the outer edge of the flow-blocking end face and the inner wall of the outer sleeve. A conical guide surface is formed on the other side of the diversion block. The conical guide surface gradually contracts towards the axis of the cable inner core tube in a direction away from the flow-blocking end face and smoothly transitions to the outer wall of the cable inner core tube.

[0009] Furthermore, a heating cylinder is provided on the side of the main body of the machine head, and an extrusion screw is rotatably provided inside the heating cylinder. The discharge end of the heating cylinder is connected to the feed port on the side wall of the outer sleeve through a connecting pipe, and a filter screen is provided at the connection between the connecting pipe and the feed port. A wire insertion inlet coaxially connected to the inner core tube of the cable is provided on the rear end face of the main body of the machine head.

[0010] Furthermore, the inner lining channel has a forming component located at the other end of the deformable section. The forming component includes a sizing mold tube and an inner mold tube that is coaxially inserted inside the sizing mold tube and can move axially. One end of the sizing mold tube is connected to the second annular diverting channel. The outer wall of one end of the inner mold tube is slidably sealed to the inner wall of the sizing mold tube, and its interior has a tapered guide hole that gradually narrows along the feeding direction. The end of the cable inner core tube extends coaxially into the tapered guide hole and forms an annular covering channel with the inner wall of the tapered guide hole.

[0011] Furthermore, the other end of the sizing tube extends to the outside of the inner lining channel and its inner wall is provided with a conical pressure ring. The other end of the inner tube is provided with several elastic arc-shaped flaps with overlapping side edges to form an annular extrusion nozzle. The outer wall of the elastic arc-shaped flaps abuts against the conical pressure ring. The inner tube drives the elastic arc-shaped flaps to slide and contract along the conical pressure ring by axial movement to adjust the orifice diameter of the annular extrusion nozzle.

[0012] Furthermore, a sliding adjustment mechanism is provided on the section of the sizing mold tube extending to the outer side of the inner lining flow channel. The sliding adjustment mechanism includes an axial guide groove and an adjusting external thread formed on the sizing mold tube. The adjusting external thread covers the length region of the axial guide groove along the axial direction. A transmission guide block is fixed on the outer wall of the inner mold tube. The transmission guide block passes through the axial guide groove and extends to the outside of the sizing mold tube. An adjusting nut sleeve is screwed onto the adjusting external thread. An annular groove is formed on the inner wall of the adjusting nut sleeve. The extended end of the transmission guide block is adapted to be embedded in the annular groove.

[0013] Furthermore, each of the elastic arc-shaped petals has a sliding contact protruding from its outer wall, and the elastic arc-shaped petals slide in contact with the inner surface of the conical pressure ring through the sliding contact. At the end of each of the elastic arc-shaped petals, extending to the outer edge of the sizing mold tube, there is also a flat, arc-shaped lip.

[0014] Furthermore, the upper part of the frame and located on one side of the extrusion molding assembly are provided with a traction mechanism for pulling the extruded cable product. The traction mechanism includes a fixed bracket, the top of which is connected to a traction cylinder. A traction ring is sleeved inside the traction cylinder. Multiple traction active friction wheels are arranged in a circumferential array inside the traction ring. The surfaces of the multiple traction active friction wheels form a concave arc-shaped traction surface that matches the outer contour of the cable product. The multiple traction active friction wheels form a circular traction channel through which the cable product passes by the concave arc-shaped traction surface.

[0015] Furthermore, an electric rotary drive module is provided between the traction cylinder and the traction ring. The electric rotary drive module is used to drive the traction ring to rotate relative to the axis of the traction cylinder around the finished cable.

[0016] Furthermore, a centering guide sleeve is coaxially installed at both ends of the traction cylinder opening. The inner hole of the centering guide sleeve is a bidirectional flared shape that expands outward at both ends and contracts in the middle. The inner wall of the centering guide sleeve is also coated with a wear-resistant ceramic layer.

[0017] Compared with the prior art, the beneficial effects that the present invention can achieve include at least the following:

[0018] 1. This invention constructs a dynamic balance system in which the flow channel boundary can be adaptively adjusted according to changes in internal pressure by coaxially sleeved with a flexible thin-walled metal sleeve in the middle section of the inner lining channel and using a grid plate to separate the flexible thin-walled metal sleeve and the inner lining channel to form multiple independent pressure regulating chambers. Combined with the pressure medium connected to the medium injection port, this system can effectively suppress pressure pulsations during the melt delivery process. At the same time, by differentially adjusting the medium pressure in each pressure regulating chamber, online precision correction of the concentricity of the insulation layer is achieved, significantly improving the dimensional accuracy of the finished cable.

[0019] 2. This invention, by setting a flow-blocking block with a flow-blocking end face and a conical flow-guiding surface inside the first annular flow-blocking channel, utilizes a physical barrier and forced flow-blocking mechanism to transform the unstable initial melt flow into an annular flow with equal pressure and velocity. This allows the melt to pass through the annular gap between the outer edge of the flow-blocking end face and the inner wall of the outer sleeve for rectification, and smoothly converge along the conical flow-guiding surface to the surface of the cable inner core tube. This ensures that the melt entering the subsequent deformable section has a high degree of circumferential uniformity, guaranteeing the consistency of the cable insulation layer thickness in the circumferential direction from the structural source.

[0020] 3. This invention, by setting an axially movable inner mold tube and its end elastic arc-shaped flap, in conjunction with the conical guide inner hole and conical pressure ring inside the sizing mold tube, realizes online linkage fine adjustment of the insulation layer wall thickness and the outer diameter of the finished product without stopping the machine. The displacement of the inner mold tube drives the conical guide inner hole to change the cross-sectional gap of the annular wrapping flow channel, and simultaneously drives the elastic arc-shaped flap to slide and contract along the conical pressure ring to adjust the orifice diameter of the annular extrusion nozzle. This not only effectively suppresses the mold-separation expansion effect of the melt, but also uses the flat lip at the end of the flap to perform secondary micro-pressing and smoothing on the surface of the cable, eliminating mold closing marks and ensuring the smoothness and roundness of the finished product surface.

[0021] 4. This invention achieves flexible, encircling traction and dynamic force distribution for soft plastic cables by incorporating a traction active friction wheel with a concave arc-shaped traction surface and an electric rotary drive module in the traction mechanism. The traction active friction wheel disperses radial clamping pressure through a spiral contact trajectory, effectively preventing longitudinal indentations caused by continuous pressure under a fixed path. Combined with bidirectional flared centering guide sleeves with wear-resistant ceramic layers at both ends of the traction cylinder, this ensures coaxial alignment of the cable while minimizing sliding friction resistance, preventing scratches on the cable surface, and comprehensively optimizing the appearance quality of the finished cable. Attached Figure Description

[0022] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the accompanying drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. In all the drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, the elements or parts are not necessarily drawn to scale.

[0023] Figure 1 This is a schematic diagram of the overall structure of the extruder of the present invention;

[0024] Figure 2 This is a schematic diagram of the internal structure of the main body of the machine head of the present invention;

[0025] Figure 3 This is a schematic diagram of the axial structure of the pressure regulating cavity formed by the flexible metal thin-walled sleeve and the inner lining flow channel of the present invention;

[0026] Figure 4 For the present invention Figure 1 A partially enlarged structural diagram of the sizing mold tube and the inner mold tube in the diagram;

[0027] Figure 5 This is a schematic diagram of the annular extrusion nozzle formed by the elastic arc-shaped flaps of the present invention.

[0028] Figure 6 This is a schematic diagram of the external partial pipe section structure of the sizing die pipe of the present invention;

[0029] Figure 7 This is a partial structural diagram of the traction structure of the present invention;

[0030] Figure 8 This is a schematic diagram of the axial internal structure of the traction cylinder and traction ring of the present invention.

[0031] In the above figures, the reference numerals are as follows: 1. Frame; 21. Head body; 211. Deformable section; 212. Flexible thin-walled metal sleeve; 213. Grating plate; 214. Pressure regulating chamber; 221. Outer sleeve; 222. Cable inner core tube; 2221. First annular diversion channel; 2222. Second annular diversion channel; 223. Diversion block; 2231. Flow-blocking end face; 2232. Conical guide surface; 231. Sizing mold tube. ; 2311, conical pressure ring; 232, inner mold tube; 2321, annular wrapping flow channel; 233, elastic arc-shaped flap; 2331, flat convex lip; 241, axial guide groove; 242, adjusting external thread; 243, transmission guide block; 244, adjusting nut sleeve; 3, heating barrel; 31, extrusion screw; 41, traction cylinder; 411, centering guide sleeve; 42, traction ring; 421, traction active friction wheel; 5, cable core.

[0032] The realization of the objective, functional features and advantages of the present invention will be further explained below with reference to the embodiments and the accompanying drawings. Detailed Implementation

[0033] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. 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.

[0034] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present invention are only used to explain the relative positional relationship and movement of each component in a specific posture. If the specific posture changes, the directional indication will also change accordingly.

[0035] In this invention, unless otherwise explicitly specified and limited, the terms "connection," "fixed," etc., should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral part; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be 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 invention according to the specific circumstances.

[0036] Furthermore, if the embodiments of the present invention involve descriptions using terms such as "first," "second," etc., these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Moreover, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or system that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or system. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or system that includes that element.

[0037] Example:

[0038] It is understandable that, since existing extruder head channels typically use rigid metal walls, their cross-sectional area and volume are constant. When polyolefin melt generates high-frequency pressure pulsations during screw conveying due to changes in shear rate, differences in raw material viscosity, or fluctuations in screw speed, the rigid channel wall cannot buffer or compensate for the fluid pressure through physical deformation. This pressure fluctuation is directly transmitted to the discharge die, causing instability in extrusion pressure. Consequently, the insulation layer ultimately covering the cable core exhibits uneven axial thickness or radial concentricity deviation.

[0039] Therefore, this embodiment provides a polyolefin insulated flexible cable extruder. Clearly, it is a core molding equipment used in the continuous production of insulation and sheathing layers for various flexible cables (soft cables), and is particularly suitable for precision extrusion processing of polyolefin melt materials such as polyethylene and polypropylene, which have non-Newtonian fluid characteristics and are sensitive to pressure shear. Specifically, it is a dedicated pressure-stabilizing extrusion device that breaks through the limitations of traditional rigid flow channels by constructing a flexible variable flow channel structure to achieve adaptive buffering and dynamic balance adjustment of melt pressure pulsations, thereby ensuring the extrusion quality of flexible cables.

[0040] For example, please refer to Figures 1 to 3 Its structure mainly includes a frame 1 and an extrusion molding assembly set on the upper part of the frame 1. The core of the extrusion molding assembly is the die head body 21, which has an inner liner channel for melt flow. Unlike the traditional one-piece rigid channel, this solution has a flexible metal thin-walled sleeve 212 coaxially sleeved in the middle section of the inner liner channel. The two ends of the flexible metal thin-walled sleeve 212 are rigidly fixed to the inner wall of the inner liner channel to ensure overall sealing, while the surface between the two ends is in a non-rigid constraint state, thereby curling to form the deformable section 211 of the inner liner channel. Thus, in terms of spatial structure, the outer surface of the flexible metal thin-walled sleeve 212 does not directly fit the inner liner channel, but an annular gap is reserved between them (in this embodiment, the inner liner channel expands radially outward at the position corresponding to the flexible metal thin-walled sleeve 212, such as...). Figure 2 As shown, the annular gap forms an independent accommodating space; of course, in other embodiments, the inner lining channel can also remain a straight pipe of equal diameter, and the annular gap is reserved only by reducing the outer diameter of the thin-walled sleeve. In order to achieve fine support and partition control of the flexible structure, the annular gap is provided with multiple grid plates 213 in the internal array. These grid plates 213 play the role of physical isolation and support, forcibly dividing the originally connected annular gap into multiple independent pressure regulating chambers 214. Correspondingly, several medium injection ports are opened on the outer shell of the machine head body 21. These injection ports correspond one-to-one with the above-mentioned multiple pressure regulating chambers 214 and are connected to them for connecting external pressure medium.

[0041] Furthermore, to coordinate with the aforementioned flexible flow channel and achieve synchronous transport of the cable core 5, this embodiment further includes a diverter located at one end of the deformable section 211 inside the inner lining flow channel. This diverter employs a double-layer sleeve structure, specifically including an outer sleeve 221 closed at one end and a cable core insert 222 coaxially sleeved inside the outer sleeve 221. One end of the cable core insert 222 extends forward and passes through the deformable section 211 to guide the cable core 5 through in a straight line. In terms of structural fit, the cable core 5... Fluid channels are maintained between the outer wall of the inner core tube 222 and the inner wall of the outer sleeve 221, as well as between the outer wall and the inner wall of the deformable section 211, thus forming a first annular diversion channel 2221 and a second annular diversion channel 2222 that are interconnected. The molten material first enters the first annular diversion channel 2221 for preliminary rectification, and then enters the second annular diversion channel 2222, which is enclosed by the inner core tube 222 and the flexible metal thin-walled sleeve 212 (i.e., the deformable section 211), for voltage stabilization. This diversion structure design not only realizes the coaxial combination of the cable core 5 and the molten material flow channel, but also ensures that the molten material has a stable laminar flow state before entering the flexible adjustment area, avoiding turbulence caused by structural abrupt changes from interfering with the adjustment effect of the flexible wall.

[0042] This solution constructs a dynamic balance system in which the flow channel volume can be adaptively adjusted according to changes in internal pressure by using the flexible metal thin-walled sleeve 212 designed above in conjunction with the pressure regulating cavity 214 on its outer side. In specific implementation, a fluid medium with a preset pressure is injected into each pressure regulating cavity 214 through the medium injection port. The pressure of the fluid medium acts on the outer surface of the flexible metal thin-walled sleeve 212, providing it with constant radial inward pressure support. This allows it to perform radial elastic displacement according to the real-time changes in the melt pressure in the second annular diversion channel 2222, thereby giving the inner lining flow channel a radial deformation compensation space.

[0043] Specifically, when the melt pressure in the second annular diversion channel 2222 increases instantaneously due to front-end fluctuations and exceeds the set medium pressure in the pressure regulating chamber 214, the high-pressure melt forces the flexible metal thin-walled sleeve 212 to overcome the outer medium pressure and generate radially outward (i.e., away from the axis of the cable core 5) elastic expansion deformation, thereby increasing the flow cross-section and local volume of the second annular diversion channel 2222 and reducing the peak melt pressure. Conversely, when the melt pressure in the second annular diversion channel 2222 instantly decreases to below the set medium pressure in the outer pressure regulating chamber 214, the flexible metal thin-walled sleeve 212 generates radially inward (i.e., closer to the cable core) elastic expansion deformation under the pressure of the medium pressure in the pressure regulating chamber 214. The contraction deformation of the 5-axis reduces the cross-section and local volume of the second annular diversion channel 2222, thereby squeezing the melt to supplement the flow channel pressure. Furthermore, due to the independent isolation design of the multiple pressure regulating cavities 214, this solution also has an online fine-tuning function for the eccentricity of the insulation layer. In specific operation, if a local thickness deviation is found in the circumferential direction of the extruded cable insulation layer, the technician can adjust the medium pressure in the corresponding pressure regulating cavity 214 in a differentiated manner. By changing the radial displacement of the flexible metal thin-walled sleeve 212 in that specific area, the size of the melt flow gap in that direction is finely adjusted, thereby balancing the melt flow velocity distribution in the circumferential direction and achieving precise correction of the concentricity of the finished product.

[0044] Based on this, this embodiment utilizes the dynamic mechanical balance mechanism between the inner melt pressure and the outer regulating cavity medium pressure of the flexible metal thin-walled sleeve 212 to effectively suppress pressure pulsation during melt delivery. At the same time, combined with the refined control of the independent chamber, it ensures that the melt flowing through the deformable section 211 enters the subsequent forming process under a constant and uniform pressure. This constant extrusion back pressure not only eliminates axial thickness fluctuations but also ensures the compactness of the melt when covering the cable core 5, thereby solving the problem of insufficient density of the insulation layer of existing cable products and further improving the dimensional accuracy, concentricity, density and appearance quality of the insulation layer of flexible cables, ultimately improving the quality of the finished cable products.

[0045] In some embodiments, to balance high-temperature resistance and excellent elastic fatigue life, the flexible metal thin-walled sleeve 212 is preferably made of a high-yield-strength elastic alloy material, such as beryllium bronze alloy, titanium alloy, or high-strength spring steel, with a wall thickness between 0.5 mm and 2.0 mm, to ensure that no plastic deformation or fatigue fracture occurs under long-term high-frequency pressure pulsation conditions. The pressure medium is preferably high-temperature resistant hydraulic oil or methyl silicone oil to ensure good thermal stability and incompressibility at polyolefin extrusion temperatures (typically 150℃-250℃), enabling precise pressure transmission.

[0046] Furthermore, regarding the independent sealing of the pressure regulating chamber 214, the grating plate 213 is preferably a rigid rib structure integrally formed or welded to the inner wall of the lining channel. During assembly, the outer surface of the flexible metal thin-walled sleeve 212 is continuously and sealed to the top end face of each grating plate 213 via high-energy laser welding or precision brazing. This connection method ensures rigid anchoring between the flexible metal thin-walled sleeve 212 and the grating plate 213, preventing cross-flow of the medium between adjacent pressure regulating chambers 214.

[0047] Based on the above embodiments, as a further optional implementation, such as Figure 2 As shown, the first annular diversion channel 2221 is further provided with a diversion block 223 sleeved on the outside of the cable inner core tube 222. The diversion block 223 is conical, and a flow-blocking end face 2231 is formed on one side. An annular gap is formed between the outer edge of the flow-blocking end face 2231 and the inner wall of the outer sleeve. A conical guide surface 2232 is formed on the other side of the diversion block 223. The conical guide surface 2232 gradually shrinks towards the axis of the cable inner core tube 222 in a direction away from the flow-blocking end face 2231 and smoothly transitions to the outer wall of the cable inner core tube 222.

[0048] It is understandable that during the operation of the extruder, when the molten polyolefin material enters the die head channel through the barrel, there is often a local pressure gradient or flow rate difference in the circumferential direction. If this unhomogenized melt directly enters the subsequent second annular diversion channel 2222, it will cause the flexible metal thin-walled sleeve 212 to have inconsistent stress states in different circumferential directions, which will cause deviations in the adjustment response at various points in the channel, ultimately resulting in uneven thickness of the extruded cable insulation layer in the circumferential direction.

[0049] Therefore, this solution, by setting the flow-diverting block 223, utilizes physical obstruction and forced flow-diversion mechanisms to transform the unstable initial melt flow into a uniform annular flow. Specifically, during melt flow, the flow-diverting block 223 is located on the necessary path of the melt flow. When melt with velocity differences arrives at this area, the flow-diverting end face 2231 first axially cuts off the mainstream core of the melt, forcing the melt streamline to change from axial flow to radially outward diffusion flow. Subsequently, driven by the accumulated pressure, the melt is forced to fill and pass through the outer edge of the flow-diverting end face 2231 and... The annular gap defined between the inner and outer walls of the outer sleeve is used to rectify the melt into an annular melt with equal pressure and flow rate by utilizing the geometric uniformity of the annular gap. Finally, the rectified annular melt smoothly converges towards the axis along the slope direction of the conical guide surface 2232 and seamlessly adheres to the surface of the inner core tube 222 of the cable to form a uniform annular fluid column. This ensures that the subsequent flexible metal thin-walled sleeve 212 can synchronously adjust the uniformly distributed melt, thereby achieving the thickness consistency of the insulation layer of the finished flexible cable in the circumferential direction and improving the quality of the finished cable.

[0050] Based on the above embodiments, as a further optional implementation method, in Figure 1 As shown in the figure, a heating cylinder 3 is also provided on the side of the head body 21. An extrusion screw 31 is rotatably provided inside the heating cylinder 3. The discharge end of the heating cylinder 3 is connected to the feed port on the side wall of the outer sleeve through a connecting pipe. A filter screen is provided at the connection between the connecting pipe and the feed port. A wire insertion inlet coaxially connected to the inner core tube 222 of the cable is opened on the rear end face of the head body 21.

[0051] In the specific implementation of this scheme, the continuous rotation of the extrusion screw 31 is used to spirally extrude and convey the molten material in the heating barrel 3, forcing the material to pass through the filter screen via the connecting pipe and smoothly inject it into the feed port on the side wall of the outer sleeve; at the same time, the cable core 5 is introduced in a straight line through the wire insertion inlet and enters the inner core insertion tube 222 of the cable along the axial direction.

[0052] Clearly, based on the above structure, this solution not only achieves continuous plasticization and pressurized conveying of polyolefin granular raw materials, but also effectively filters out unmelted particles and impurities in the melt by utilizing the physical interception effect of the filter screen, ensuring the purity of the melt entering the precision flow channel of the die head; at the same time, the coaxial setting of the rear wire inlet provides a straight and smooth guide path for the cable core 5, ensuring the coaxial alignment of the cable core 5 and the die head flow channel, thereby meeting the basic process requirements for continuous extrusion production of flexible cables.

[0053] In some embodiments, to ensure the plasticizing quality and conveying stability of polyolefin raw materials, the structure of the heating barrel 3 and the extrusion screw 31 is illustrated here:

[0054] The heating cylinder 3 is a cylindrical body with a feed hopper on the side, which is used to receive external granular raw materials. A drive mechanism is also connected to one end of the cylinder. The drive mechanism is preferably a drive motor including a gearbox. The output end of the drive motor is connected to the tail end of the extrusion screw 31 (e.g., through a spline or flat key) through the output shaft of the gearbox, thereby ensuring that the extrusion screw 31 can obtain a constant and strong rotational driving force when facing high-viscosity polyolefin melt, and maintain the precise stability of the extrusion volume.

[0055] Obviously, a layer of spirally distributed ceramic heating tiles is tightly attached to the inner wall of the heating barrel 3 along its axial direction. The continuous spiral distribution of the ceramic heating tiles eliminates the axial cold gaps that may occur with traditional segmented heating, creating a uniform external thermal field. Simultaneously, the extrusion screw 31 is constructed with a gradually decreasing compression structure, specifically, the screw groove depth (or pitch) gradually decreases from the feed end to the discharge end. This structural combination ensures that the material undergoes continuous and stable forced compression during forward transport. This not only forces the material to adhere tightly to the hot inner wall of the barrel to maximize heat conduction efficiency but also utilizes internal frictional heat under high pressure to assist plasticization. Thus, while simplifying the structure, it ensures that the final output melt has a highly consistent temperature uniformity and dense structure.

[0056] Based on the above embodiments, as a further optional implementation method, in Figure 2 and Figure 4 As shown in the diagram, the inner lining flow channel has a molding component located at the other end of the deformable section 211. The molding component includes a sizing mold tube 231 and an inner mold tube 232 that is coaxially inserted inside the sizing mold tube 231 and can move axially. One end of the sizing mold tube 231 is connected to the second annular diversion channel 2222. The outer wall of one end of the inner mold tube 232 is slidably sealed to the inner wall of the sizing mold tube 231, and its interior has a tapered guide hole that gradually narrows along the feeding direction. The end of the cable inner core tube 222 extends coaxially into the tapered guide hole and forms an annular covering flow channel 2321 with the inner wall of the tapered guide hole.

[0057] Understandably, since the die gap of a conventional extruder is fixed, if the extruded insulation layer is found to be too thin or too thick during production, or if different specifications of cables need to be produced, the machine must usually be stopped, disassembled, and replaced with a die core or sleeve of a different diameter. This will cause the extruder to stop production and is inefficient. Therefore, in this embodiment, through a cleverly designed axially movable inner die tube 232 and its internal tapered guide hole, the technical problem of the conventional die head's difficulty in fine-tuning the discharge gap and melt back pressure online is solved by utilizing the principle of relative position change between the tapered surface of the tapered guide hole and the cylindrical surface at the end of the cable inner core tube 222 during the final extrusion molding stage.

[0058] In actual implementation, since the position of the inner core tube 222 of the cable is relatively fixed, when the inner mold tube 232 is controlled to slide slightly along the axial direction, the tapered guide hole inside it will move synchronously. Based on the geometric characteristics of a cone, this axial displacement will directly translate into a change in the radial distance between its tapered inner wall and the outer wall of the inner core tube 222 of the cable (i.e., change the cross-sectional width of the annular covering flow channel 2321). For example, when the inner mold tube 232 is driven to move against the direction of melt flow (i.e., closer to the inner core of the cable), When the inner mold tube 232 moves in the direction of melt flow (i.e., extends forward away from the inner mold tube 222), its constricted section gradually approaches the inner mold tube 222, causing the annular gap to narrow. At this time, the resistance to melt flow increases, the discharge back pressure rises, and the extruded insulation layer is thinner and the structure is denser. Conversely, when the inner mold tube 232 moves in the direction of melt flow (i.e., extends forward away from the inner mold tube 222), its conical inner hole gradually moves away from the tube, causing the annular gap to widen, the flow resistance to decrease, the discharge back pressure to decrease, and the wall thickness of the extruded insulation layer to increase relatively. Specifically, inside the inner mold tube 232, when the cable core 5 passes through at high speed, the annular melt under pressure converges towards the center along the constricted slope of the conical guide inner hole, and at the end outlet of the conical guide inner hole, it initially coats the surface of the cable core 5 to form an insulation layer with a specific thickness. That is, through the axial displacement of the inner mold tube 232, the throttling resistance before the melt convergence point is dynamically changed, thereby realizing the control and adjustment of the final coating thickness. Meanwhile, the sliding seal between the inner mold tube 232 and the sizing mold tube 231 ensures that the melt will not overflow or leak during the adjustment process.

[0059] This solution enables effective adjustment of the insulation layer wall thickness and density without stopping the machine. While avoiding production interruptions, it significantly improves the dimensional accuracy and process flexibility of the finished product, thereby greatly improving the production efficiency of the extruder and enhancing its performance.

[0060] In some embodiments, a sliding seal is used between the inner mold tube 232 and the sizing mold tube 231. Specifically, the outer periphery of the inner mold tube 232 is provided with at least one set of high-temperature resistant sealing components, or a damping seal structure is formed by a high-precision clearance fit. In actual implementation, the sealing components or clearance fit are used to block the path of high-pressure melt overflowing backward, while ensuring that the inner mold tube 232 has sufficient flexibility when adjusting axial movement. Those skilled in the art can select existing high-temperature sealing rings, packing seals, or metal labyrinth seal structures according to the melt pressure and temperature parameters, which is not the focus of this application, so the details of the sliding seal will not be described here.

[0061] As a further optional implementation, such as Figure 4 As shown, the other end of the sizing tube 231 extends to the outside of the inner lining channel, and its inner wall is provided with a conical pressure ring 2311. The other end of the inner tube 232 is provided with several elastic arc-shaped flaps 233 with overlapping side edges to form an annular extrusion nozzle (such as...). Figure 5 As shown), the outer wall of the elastic arc-shaped flap 233 abuts against the conical pressure ring 2311, and the inner mold tube 232 drives the elastic arc-shaped flap 233 to slide and contract along the conical pressure ring 2311 by axial movement to adjust the orifice diameter of the annular extrusion nozzle.

[0062] It should be noted that although this solution achieves effective adjustment of the insulation layer wall thickness during cable extrusion, in the final stage of the actual extrusion process (i.e., at the moment of demolding), the polymer melt often exhibits "demolding expansion" due to pressure release. Furthermore, the cable core 5 itself has a slight diameter tolerance. The rigid sizing mold in the existing technology cannot actively adapt to this volume change, which can easily lead to out-of-tolerance outer diameter dimensions or sheath loosening due to insufficient covering force in the finished cable.

[0063] Therefore, this solution constructs a variable-diameter annular extrusion nozzle structure by cooperating with the elastic arc-shaped flap 233 added to the end of the inner mold tube 232 and the conical pressure ring 2311 added to the inner wall of the sizing mold tube 231. On the basis of controlling and adjusting the wall thickness of the insulation layer, it further realizes the physical constraint and precise sizing of the final outer diameter of the finished cable.

[0064] Specifically, in actual implementation, the inner mold tube 232 serves as the driving component, and the sizing mold tube 231 and its conical pressure ring 2311 serve as relatively fixed constraint components. When the inner mold tube 232 undergoes axial displacement, the elastic arc-shaped flap 233 at its end moves accordingly. Since the outer wall of the elastic arc-shaped flap 233 always abuts against the conical surface of the conical pressure ring 2311, the axial thrust of the inner mold tube 232 forces the elastic arc-shaped flap 233 to slide along the inclined surface of the conical pressure ring 2311. Guided by the inclination of the conical surface, the elastic arc... During the sliding process, the shaped petal plate 233 is forced to generate radial displacement (i.e., contraction or expansion) towards the central axis. During this process, since the side edges of the elastic arc-shaped petal plate 233 are arranged in a layered overlapping manner, when each petal plate contracts and moves towards the center, the side edges of adjacent petal plates slide and cover each other, ensuring the continuity of the inner wall of the annular extrusion nozzle formed by the enclosure and avoiding gaps. In this way, the actual through-hole diameter of the annular extrusion nozzle is directly changed through the above actions, thereby applying physical limiting and shaping effects to the outer layer of the cable passing through the nozzle.

[0065] Therefore, this embodiment utilizes the mechanical combination of conical guidance and elastic contraction to convert the axial adjustment of the inner die tube 232 into a radial diameter change of the discharge nozzle. This radial physical constraint is applied to the molten insulation layer, further densifying it and achieving final sizing. Simultaneously, the smoothing effect of the end-mounted flat lip 2331 eliminates the die-scraping effect, resulting in a cable product with a smooth surface and precise dimensions. This not only effectively suppresses the die-scraping effect of the melt but also ensures a highly rounded and dense cable surface, completely solving the technical deficiency of existing extruders that cannot simultaneously control wall thickness and outer diameter sizing due to a single rigid die tube.

[0066] In some embodiments, the elastic arc-shaped flap 233 is made of an alloy material with high resilience and wear resistance. In the initial assembled state, the side edges of two adjacent flaps are fitted and covered by inclined wedge-shaped surfaces, so that when the elastic arc-shaped flap 233 contracts, the adjacent side edges can slide relative to each other without separating, thus maintaining the circumferential sealing of the nozzle inner wall and preventing the melt from getting stuck in the gaps or causing surface extrusion marks. Preferably, the outer surface of the elastic arc-shaped flap 233 is hardened and polished to reduce the coefficient of sliding friction between it and the conical pressure ring 2311, ensuring the sensitivity of the adjustment action.

[0067] Based on the above embodiments, please further refer to... Figure 4 and Figure 6A sliding adjustment mechanism is also provided on the section of the fixed-sizing mold tube 231 extending to the outer pipe section of the inner lining flow channel. The sliding adjustment mechanism includes an axial guide groove 241 and an adjusting external thread 242 formed on the fixed-sizing mold tube 231. The adjusting external thread 242 covers the length region of the axial guide groove along the axial direction. A transmission guide block 243 is fixed on the outer wall of the inner mold tube 232. The transmission guide block 243 passes through the axial guide groove 241 and extends to the outside of the fixed-sizing mold tube 231. An adjusting nut sleeve 244 is screwed onto the adjusting external thread 242. An annular groove is formed on the inner wall of the adjusting nut sleeve 244. The extended end of the transmission guide block 243 is adapted to be embedded in the annular groove.

[0068] Understandably, this embodiment, through the setting of the above-mentioned sliding adjustment mechanism, utilizes the displacement conversion characteristics of the threaded transmission to realize the conversion of external rotational operation into precise axial linear feed of the internal mold tube 232.

[0069] Specifically, during actual adjustment, the operator rotates the adjusting nut sleeve 244, which, through the meshing action of the threaded pair, causes it to move axially along the guide groove. This, in turn, drives the transmission guide block 243 embedded therein to slide axially synchronously through the annular groove. During this process, the axial guide groove 241 limits and prevents the transmission guide block 243 from rotating, thus forcibly constraining the inner mold tube 232 to only perform simple axial translation and not to follow the rotation. In this way, this solution achieves axial sliding adjustment of the inner mold tube 232, so that after the inner mold tube 232 moves, it can drive the tapered guide inner hole (or the elastic arc-shaped flap 233 at its end) to produce a precise axial displacement relative to the sizing mold tube 231 or the cable inner core tube 222, thereby directly changing the cross-sectional gap of the annular wrapping flow channel 2321 or the diameter of the discharge nozzle.

[0070] Based on this, this solution not only enables online fine-tuning of the cable insulation layer thickness, density, and dimensions without shutting down the machine, but also ensures the stability of the adjustment position under high extrusion pressure by utilizing the self-locking characteristics of the threaded pair. Furthermore, it should be noted that since the axial guide groove 241 is opened on the pipe section extending from the sizing die tube 231 to the outside of the inner lining flow channel, the adjustment mechanism is completely isolated from the internal high-pressure melt chamber in space through a sealed fitting section. Thus, while realizing the external adjustment function, the risk of melt overflowing and leaking through the gap of the adjustment mechanism is completely eliminated from the structure.

[0071] Based on the above embodiments, as a further preferred implementation, in Figure 4As shown in the figure, the outer walls of several elastic arc-shaped petal plates 233 are provided with sliding contacts, and the elastic arc-shaped petal plates 233 slide in contact with the inner surface of the conical pressure ring 2311 through the sliding contacts. At the end of several elastic arc-shaped petal plates 233, extending to the outer edge of the sizing mold tube 231, there is also a flat arc-shaped lip 2331.

[0072] Understandably, to avoid excessive frictional resistance between the outer wall of the elastic arc-shaped valve 233 and the conical pressure ring 2311 due to large-area contact, which could cause the elastic arc-shaped valve 233 to sluggishly adjust, jam, or be damaged, this solution specifically provides a sliding contact protruding from the outer wall of the elastic arc-shaped valve 233. This contact slidingly engages with the inner surface of the conical pressure ring 2311, transforming the original full-surface contact between the two into a point contact with an extremely low coefficient of friction. This significantly reduces the contact area and friction between the elastic arc-shaped valve 233 and the conical pressure ring 2311 during actual adjustment, ensuring that the inner mold tube 232 is smoother and more sensitive when driving the elastic arc-shaped valve 233 to contract or expand, and ensuring the consistency of force on all valves.

[0073] In addition, to avoid scratching or leaving mold marks on the surface of the still soft high-temperature melt during the shrinkage process of the end edge of the segmented structure, this solution also sets an arc-shaped flat lip 2331. In the final stage of cable extrusion, the flat lip 2331 uses its smooth arc surface to perform secondary micro-pressing and smoothing on the surface of the cable insulation layer that has just left the nozzle, thereby effectively eliminating the fine ridges that may be generated by the segment joints and ensuring that the surface of the final formed cable sheath has a high degree of roundness and smoothness.

[0074] Based on the above embodiments, as an optional implementation, the upper part of the frame 1, located on one side of the extrusion molding assembly, is further provided with a traction mechanism for pulling the extruded cable product, such as... Figure 7 As shown, the traction mechanism includes a fixed bracket, with a traction cylinder 41 connected to the top of the fixed bracket. A traction ring 42 is sleeved inside the traction cylinder 41. The traction ring 42 has multiple traction active friction wheels 421 arranged in a circumferential array inside. The surfaces of the multiple traction active friction wheels 421 form a concave arc-shaped traction surface that matches the outer contour of the finished cable. The multiple traction active friction wheels 421, through the concave arc-shaped traction surface, form a circular traction channel through which the finished cable passes. Figure 8 (As shown in the image).

[0075] Understandably, after the cable is extruded, a traction mechanism is needed to provide continuous and stable axial tension to transport the freshly extruded cable to the subsequent winding device at a constant speed. However, at this time, the insulation layer on the cable surface is still in a high-temperature semi-molten or incompletely cured soft plastic state, and its resistance to compressive deformation is extremely weak.

[0076] To address this, this solution employs an active friction wheel arranged in a circumferential array with a concave arc-shaped traction surface. This wheel's shape, adapted to the outer contour of the finished cable, achieves a wrapping surface contact with the cable. During actual traction, this large-area contact not only significantly increases the effective friction area, ensuring stable transmission of traction force, but more importantly, it evenly distributes the radial clamping pressure required for traction across the cable's circumferential surface. This effectively reduces localized pressure per unit area, ensuring that the cable, in its soft plastic state, is not prone to cross-sectional flattening or shape distortion due to concentrated force during continuous transport, thus maintaining good roundness of the finished product.

[0077] For example, during traction, when the extruded cable product passes through the circular traction channel, multiple traction active friction wheels 421 rotate synchronously under the action of the drive source. In this way, by utilizing the frictional contact between the concave arc-shaped traction surface and the outer wall of the cable, their rotational motion is converted into an axial linear traction force on the cable, thereby smoothly driving the cable product to be continuously pulled and transported backward along a predetermined path.

[0078] In some embodiments, the traction active friction wheel 421 and the traction ring 42 are connected by a bearing rotating frame, and an independent micro drive motor is fixedly installed on the bearing rotating frame. The output shaft of the micro drive motor is connected to the traction active friction wheel 421 through a coupling to provide it with rotational traction power.

[0079] Meanwhile, as a preferred option, in order to adapt to different wire diameters and establish effective frictional traction, a radial adjustment component (such as a hydraulic telescopic rod or a pneumatic push rod) is preferably provided between the bearing rotating frame and the traction ring 42. In the actual installation state, one end of the radial adjustment component is fixed to the inner wall of the traction ring 42, and the other end is connected to the bearing rotating frame. By driving the bearing rotating frame to move radially, the concave arc-shaped traction surface of the traction active friction wheel 421 can be forced to press against the outer surface of the finished cable with a predetermined pressure.

[0080] Based on the above embodiments, it is further preferred that an electric rotary drive module is provided between the traction cylinder 41 and the traction ring 42, the electric rotary drive module being used to drive the traction ring 42 to rotate relative to the traction cylinder 41 around the axis of the finished cable.

[0081] Obviously, in order to further improve the surface flatness of the finished cable in the soft plastic state and avoid the formation of longitudinal extrusion marks on its surface due to continuous clamping in one direction, this embodiment endows the traction component with rotation characteristics through the electric rotary drive module.

[0082] Specifically, during the traction operation, the electric rotary drive module drives the traction ring 42 to rotate at a low speed relative to the traction cylinder 41, so that the multiple traction active friction wheels 421 distributed in a circumferential array rotate to provide axial traction force while also rotating synchronously around the central axis of the finished cable.

[0083] In this way, the contact path between the traction active friction wheel 421 and the cable surface is transformed from a traditional straight-line trajectory to a continuously changing spiral trajectory. This composite motion not only enables continuous traction operations but also periodically and evenly distributes the radial clamping pressure required for traction to various angular positions on the cable surface, thereby achieving dynamic and uniform clamping of the cable surface. This effectively prevents localized continuous pressure under a fixed path and further ensures that the final output cable has a smooth surface, no longitudinal indentations, and uniform roundness.

[0084] In some embodiments, the electric rotary drive module serves as a power unit for outputting rotational torque, and can be implemented using general-purpose drive components such as a rotary drive or a hollow rotary platform. In actual implementation, those skilled in the art only need to perform conventional selection based on the traction load and rotational speed parameters required for actual production, and install it between the traction cylinder 41 and the traction ring 42 to achieve the drive function; therefore, its internal structure will not be described in detail here.

[0085] Based on the above embodiments, and more preferably, a centering guide sleeve 411 is coaxially installed at both ends of the traction cylinder 41 openings, and the inner hole of the centering guide sleeve 411 is a bidirectional flared shape that expands outward at both ends and contracts in the middle (in Figure 7 (As shown in the figure), and the inner wall of the centering guide sleeve 411 is also coated with a wear-resistant ceramic layer.

[0086] Understandably, this solution, through the aforementioned structural design, utilizes the bidirectional flared (i.e., hourglass-shaped hyperbolic contour) inner hole to construct a smooth inlet and outlet guide channel. Specifically, the flared openings at both ends serve as fault-tolerant guide zones, effectively capturing and guiding cables that experience slight vibrations and jumps, preventing the cables from scraping against the edge of the traction cylinder 41; while the constricted section in the middle serves as a precision positioning zone, ensuring that the cable always enters the traction center in a coaxial state, thereby facilitating the rotational traction operation of the finished cable.

[0087] Meanwhile, the wear-resistant ceramic layer (such as an alumina or silicon carbide coating) gives the inner wall of the guide sleeve extremely high surface hardness and extremely low coefficient of friction. This not only extends the service life of the guide sleeve under long-term friction conditions, but also reduces the sliding friction resistance between the guide wall and the cable surface in a soft plastic state. Thus, while playing a limiting and guiding role, it prevents the smooth surface of the cable insulation layer from being scratched or worn due to excessive friction, thereby improving the quality of the finished cable.

[0088] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

[0089] Furthermore, it should be noted that the accompanying drawings in this specification are intended to schematically illustrate the structural principles and connection relationships of the present invention. To more clearly present the internal minute features and their operational logic, the shapes, sizes, or proportions of some structures may be appropriately exaggerated or distorted in the drawings, and are mainly shown using line drawing. Therefore, the drawings are only used to assist in understanding the technical solutions of the present invention and should not be regarded as a strict limitation on the actual product size proportions or specific appearance shape of the present invention. The actual dimensions and proportional relationships of each component should be based on the actual manufacturing process and application requirements. However, the positional relationships, connection methods, and operational coordination logic between the components shown in the drawings are clear and accurate.

Claims

1. A polyolefin insulated flexible cable extruder, comprising a frame and an extrusion molding assembly disposed on the upper part of the frame, characterized in that, The extrusion molding assembly includes a die head body, an inner liner channel is formed inside the die head body, a flexible metal thin-walled sleeve is coaxially sleeved in the middle section of the inner liner channel, the two ends of the flexible metal thin-walled sleeve are fixedly connected to the inner liner channel, and its inner surface is rolled to form a deformable section of the inner liner channel. An annular gap is formed between the outer surface of the flexible metal thin-walled sleeve and the inner liner channel. Multiple grid plates are arrayed inside the annular gap, and the multiple grid plates divide the annular gap into multiple independent pressure regulating chambers. Several medium injection ports corresponding to and connected to the pressure regulating chambers are also formed on the die head body. The inner lining channel is provided with a diversion component at one end of the deformable section. The diversion component includes an outer tube closed at one end and a cable inner core tube coaxially sleeved inside the outer tube. One end of the cable inner core tube passes through the deformable section, and its outer wall surface forms a first annular diversion channel and a second annular diversion channel that are interconnected with the inner wall of the outer tube and the inner wall of the deformable section, respectively.

2. The polyolefin insulated flexible cable extruder according to claim 1, characterized in that, The first annular diversion channel is further provided with a diversion block that is sleeved on the outside of the inner core tube of the cable. The diversion block is conical and has a flow-blocking end face on one side. An annular gap is formed between the outer edge of the flow-blocking end face and the inner wall of the outer tube. A conical guide surface is formed on the other side of the diversion block. The conical guide surface gradually contracts toward the axis of the inner core tube along the direction away from the flow-blocking end face and smoothly transitions to the outer wall of the inner core tube.

3. The polyolefin insulated flexible cable extruder according to claim 1, characterized in that, The side of the main body of the machine head is also provided with a heating cylinder. An extrusion screw is rotatably provided inside the heating cylinder. The discharge end of the heating cylinder is connected to the feed port on the side wall of the outer sleeve through a connecting pipe. A filter screen is provided at the connection between the connecting pipe and the feed port. A wire insertion inlet coaxially connected to the inner core tube of the cable is provided on the rear end face of the main body of the machine head.

4. The polyolefin insulated flexible cable extruder according to claim 1, characterized in that, The inner lining channel has a forming component at the other end of the deformable section. The forming component includes a sizing mold tube and an inner mold tube that is coaxially inserted inside the sizing mold tube and can move axially. One end of the sizing mold tube is connected to the second annular diversion channel. The outer wall of one end of the inner mold tube is slidably sealed to the inner wall of the sizing mold tube, and its interior has a tapered guide hole that gradually narrows along the feeding direction. The end of the cable inner core tube extends coaxially into the tapered guide hole and forms an annular covering channel with the inner wall of the tapered guide hole.

5. A polyolefin insulated flexible cable extruder according to claim 4, characterized in that, The other end of the sizing tube extends to the outside of the inner lining channel and its inner wall is provided with a conical pressure ring. The other end of the inner tube is provided with several elastic arc-shaped flaps with overlapping side edges to form an annular extrusion nozzle. The outer wall of the elastic arc-shaped flaps abuts against the conical pressure ring. The inner tube drives the elastic arc-shaped flaps to slide and contract along the conical pressure ring by axial movement to adjust the orifice diameter of the annular extrusion nozzle.

6. The polyolefin insulated flexible cable extruder according to claim 5, characterized in that, A sliding adjustment mechanism is also provided on the section of the sizing mold tube extending to the outer side of the inner lining flow channel. The sliding adjustment mechanism includes an axial guide groove and an adjusting external thread formed on the sizing mold tube. The adjusting external thread covers the length region of the axial guide groove along the axial direction. A transmission guide block is fixed on the outer wall of the inner mold tube. The transmission guide block passes through the axial guide groove and extends to the outside of the sizing mold tube. An adjusting nut sleeve is screwed onto the adjusting external thread. An annular groove is formed on the inner wall of the adjusting nut sleeve. The extended end of the transmission guide block is adapted to be embedded in the annular groove.

7. A polyolefin insulated flexible cable extruder according to claim 5, characterized in that, Each of the elastic arc-shaped petals has a sliding contact protruding from its outer wall, and the elastic arc-shaped petals slide in contact with the inner surface of the conical pressure ring through the sliding contact. At the end of each of the elastic arc-shaped petals, extending to the outer edge of the sizing mold tube, there is also a flat, arc-shaped lip.

8. A polyolefin insulated flexible cable extruder according to claim 7, characterized in that, The upper part of the frame and located on one side of the extrusion molding assembly is also provided with a traction mechanism for pulling the extruded cable product. The traction mechanism includes a fixed bracket, the top of which is connected to a traction cylinder. A traction ring is sleeved inside the traction cylinder. Multiple traction active friction wheels are arranged in a circumferential array inside the traction ring. The surfaces of the multiple traction active friction wheels form a concave arc-shaped traction surface that matches the outer contour of the cable product. The multiple traction active friction wheels form a circular traction channel through which the cable product passes by the concave arc-shaped traction surface.

9. A polyolefin insulated flexible cable extruder according to claim 8, characterized in that, An electric rotary drive module is also provided between the traction cylinder and the traction ring. The electric rotary drive module is used to drive the traction ring to rotate relative to the axis of the traction cylinder around the finished cable.

10. A polyolefin insulated flexible cable extruder according to claim 8, characterized in that, A centering guide sleeve is coaxially installed at both ends of the traction cylinder opening. The inner hole of the centering guide sleeve is a bidirectional flared shape that expands outward at both ends and contracts in the middle. The inner wall of the centering guide sleeve is also coated with a wear-resistant ceramic layer.

Images