Pipe extrusion molding die

Abstract

This invention relates to the field of pipe extrusion die technology, specifically disclosing a pipe extrusion molding die, comprising a sleeve and a core disposed within it, forming a molding cavity. The sleeve has an inlet and an annular outlet at both ends, connecting to the molding cavity. The core consists of a conical head facing the inlet and an axially extending core portion. The molding cavity is divided into an inlet flow channel cavity and a pipe body cavity. The sleeve has a conical cavity adapted to the conical head, with the two axially abutting and equipped with circumferentially distributed, concave-convex positioning parts to achieve precise radial positioning of the core. The inlet flow channel cavity consists of multiple sets of circumferentially distributed branch channels, with the positioning parts and branch channels arranged circumferentially in an alternating pattern. The inlet ends of each branch channel converge and align with the inlet. This invention, through the concave-convex positioning structure of the conical cavity and conical head, improves the radial positioning accuracy of the core and inlet, optimizes the circumferential wall thickness uniformity of the pipe, and shortens the melt transport path of the branch channels, improving extrusion molding stability and the quality of the finished pipe.

Description

Technical Field

[0001] This invention relates to the field of pipe extrusion die technology, and more specifically to a pipe extrusion molding die. Background Technology

[0002] Existing tube extrusion molding dies, such as Figure 1 The diagram shows a flow divider bracket 51, with several circumferentially arranged plates 52 on the bracket 51 providing radial support and positioning for the mold core 53. However, this design has drawbacks. The flow divider bracket 51 needs to be axially assembled with the flow divider cone 54, which must be directly aligned with the flow channel inlet 55. This results in a misalignment between the flow divider cone and the flow channel inlet 55, leading to a deviation in the concentricity of the mold core 53 and the flow channel inlet 55. Consequently, this affects the circumferential consistency of the molded tube wall thickness. Furthermore, because the flow divider bracket 51 is located behind the flow divider cone 54, the flow channel length from the flow channel inlet 55 to the tube cavity is excessively long, reducing material replacement efficiency and impacting molding stability and quality. Summary of the Invention

[0003] To overcome the shortcomings of the prior art, the present invention provides a tube extrusion molding die, which on the one hand can effectively improve the radial positioning accuracy of the core and the feed port and improve the circumferential uniformity of tube forming; on the other hand, it reduces the length of the flow channel and improves the stability and quality of tube forming.

[0004] To achieve the above objectives, the present invention is implemented through the following technical solution: A tube extrusion molding die includes: a core and a sleeve, the core being disposed within the sleeve, a molding cavity being provided between the core and the sleeve, and an inlet and an annular outlet communicating with the molding cavity being respectively provided at both ends of the sleeve; the core includes a conical head and a tube core portion, the tip of the conical head facing the inlet, the molding cavity including an inlet flow channel cavity and a tube body cavity, the tube body cavity being disposed between the tube core portion and the sleeve; the tube core portion extends axially from the end of the conical head away from the inlet; the sleeve is provided with at least a portion of the conical head... The conical cavity is adapted to the shape of the conical head and is axially abutted. Several positioning parts with concave and convex fits are provided between the conical cavity and the conical head. The positioning parts are circumferentially distributed around the axis of the conical head. The feed channel cavity is set between the conical head and the sleeve. The feed channel cavity includes several branch channels. The branch channels are evenly distributed around the axis of the conical head and the positioning parts and branch channels are staggered in the circumferential direction. The feed ends of the branch channels converge and face the feed inlet.

[0005] Furthermore, in a tube extrusion molding die of this application, the branch flow channel is disposed in the conical cavity and the conical head. The side of the conical head is divided into several inner positioning conical surfaces by the branch flow channel, and the side of the conical cavity is divided into several outer positioning conical surfaces by the branch flow channel. The inner positioning conical surfaces and the outer positioning conical surfaces abut and fit together. The positioning part is disposed between the inner positioning conical surfaces and the outer positioning conical surfaces. In the direction from the tip to the wide end of the conical head, the width of the branch flow channel gradually increases. Adjacent branch flow channels at the wide end of the conical head tend to merge in the circumferential direction.

[0006] Furthermore, in a tube extrusion molding die of this application, the core also includes a transition core located between the conical head and the tube core portion; The forming cavity further includes an annular transition channel located between the feed channel cavity and the tube body cavity. The annular transition channel is located between the transition core and the sleeve. The annular transition channel includes a stress relief annular cavity. In the direction extending from the feed channel cavity to the tube body cavity, the width of the stress relief ring cavity in the radial direction first increases, then decreases, and finally tends to match the width of the tube body cavity. Furthermore, the radial width of the stress relief ring cavity near the feed channel cavity is smaller than the radial width near the tube body cavity.

[0007] Furthermore, in a tube extrusion molding die of this application, the annular transition channel further includes a confluence ring cavity, which is located between the stress relief ring cavity and the feed channel cavity, and the width of the confluence ring cavity is generally smaller than the width of the stress relief ring cavity in the radial direction.

[0008] Furthermore, in a tube extrusion molding die of this application, the sleeve is provided with a flow regulating ring, the flow regulating ring includes an elastic ring, the elastic ring is located radially outside the confluence ring cavity, the sleeve is provided with a plurality of extrusion members abutting against the elastic ring, the extrusion members correspond one-to-one with the branch flow channels, the position of each extrusion member is directly opposite the corresponding branch flow channel in the direction of extension of the confluence ring cavity, the extrusion members can be adjusted and moved on the sleeve to compress the elastic ring to deform in the radial direction.

[0009] Furthermore, in a tube extrusion molding die of this application, the elastic ring includes rigid bodies and spring sheets that are staggered and connected in the circumferential direction, the spring sheets correspond one-to-one with the extruder, and the extruder abuts against the spring sheets.

[0010] Furthermore, in a tube extrusion molding die of this application, the flow regulating ring further includes a support ring located at one axial end of the elastic ring. The outer surface of the flow regulating ring is provided with an annular notch. The flow regulating ring also includes an annular beam located radially inside the annular notch. The annular beam and the annular notch are located axially between the support ring and the elastic ring. The support ring and the elastic ring are integrally connected to the annular beam.

[0011] Furthermore, in this application, a tube extrusion molding die is provided, wherein the sleeve includes a feed sleeve and a discharge sleeve, the feed sleeve and the discharge sleeve are detachably connected, the feed port and the conical cavity are provided on the feed sleeve, the annular discharge port is provided on the discharge sleeve, the feed sleeve and the discharge sleeve abut against each other axially, an annular groove is provided between the feed sleeve and the discharge sleeve axially, a flow regulating ring is embedded in the annular groove, and the rigid body and the support ring abut against the side wall of the annular groove radially upward.

[0012] Furthermore, in a tube extrusion molding die of this application, the stress relief ring cavity is located radially inside the support ring, the ring groove is provided on the feed sleeve, the end of the ring groove near the discharge sleeve is open, and the two axial ends of the flow regulating ring are tightly abutted axially with the side wall of the ring groove and the end face of the discharge sleeve.

[0013] Furthermore, in a tube extrusion molding die of this application, the discharge sleeve extends radially outward from one end near the feed sleeve and is provided with a positioning ring portion. The feed sleeve is provided with a groove for receiving the positioning ring portion. The positioning ring portion is adapted to the groove and is installed in the groove. The sleeve also includes a limiting ring, which is sleeved on the discharge sleeve. The limiting ring and the feed sleeve are axially detachably connected. The upper limit of the positioning ring portion is located between the limiting ring and the groove.

[0014] As can be seen from the above technical solution, the present invention has the following beneficial effects: 1. This invention provides a tube extrusion molding die. Axial and radial positioning of the sleeve and core is achieved through the axial contact of the conical cavity and conical head. Furthermore, circumferential positioning of the sleeve and core is achieved through a positioning part. The branch flow channels are uniformly distributed circumferentially between the conical surface of the conical head and the sleeve, effectively ensuring the uniformity of tube forming. Moreover, the positioning part and the branch flow channels are integrally set on the conical head, which not only strengthens the positioning rigidity of the core and sleeve but also avoids the multi-stage assembly errors caused by traditional branch support brackets, significantly improving the symmetry of the in-mold flow field and the uniformity of the tube wall thickness.

[0015] 2. The present invention provides a tube extrusion molding die that eliminates the structure of the flow divider at one end of the conical head, reduces the length of the flow channel, and increases the material replacement rate, thereby improving the stability and quality of tube forming.

[0016] 3. This invention provides a tube extrusion molding die with a stress-relief annular cavity. Because the radial width of the stress-relief annular cavity near the feed channel is smaller than that near the tube cavity, it increases the shear rate of the molding material fluid before entering the tube cavity, thereby reducing viscosity and increasing flow rate. Furthermore, the molding material fluid entering the stress-relief annular cavity releases internal stress, allowing the molecular chains to release stress and stabilize flow behavior, avoiding uneven flow caused by excessive local shearing. The tube molding material (molten adhesive) can achieve a stable and uniform flow state before entering the tube cavity, contributing to improved molding quality consistency.

[0017] 4. The present invention provides a tube extrusion molding die, wherein the manifold cavity can increase the shear rate of the tube molding material (molten adhesive) before entering the tube cavity, and a flow regulating ring is provided outside the manifold cavity to adjust the molten adhesive in a state of lower viscosity and better fluidity, thereby significantly improving the sensitivity and accuracy of flow control. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the tube extrusion molding die in Embodiment 1 of this application; Figure 2 This is a flow channel analysis diagram of the tube extrusion molding die in Embodiment 1 of this application; Figure 3 This is a plan view of a tube extrusion molding die according to Embodiment 2 of this application; Figure 4 for Figure 3 A cross-sectional view along the AA direction; Figure 5 This is a flow channel analysis diagram of a tube extrusion molding die according to Embodiment 2 of this application; Figure 6 This is an exploded view of a component of a tube extrusion molding die according to Embodiment 2 of this application; Figure 7 This is a schematic diagram of the feed sleeve in Embodiment 2 of this application; Figure 8 This is a schematic diagram of the installation of the flow regulating ring in Embodiment 2 of this application.

[0019] In the diagram: 1-core; 11-conical head; 111-inner positioning conical surface; 112-protrusion; 12-core section; 13-transition core section; 2-Sleeve body; 201-Feed inlet; 2011-Outer positioning cone surface; 2012-Recess; 202-Annular discharge outlet; 203-Conical cavity; 204-Annular groove; 21-Feed sleeve; 211-Groove body; 22-Discharge sleeve; 221-Positioning ring; 23-Extruded part; 24-First screw; 25-Limiting ring; 26-Second screw; 27-Third screw; 3-Forming cavity; 31-Feed channel cavity; 310-Branch channel; 32-Pipe body cavity; 33-Annular transition channel; 331-Stress relief annular cavity; 332-Bulk annular cavity; 4-Flow regulating ring; 41-Support ring; 42-Elastic ring; 421-Rigid body; 422-Spring piece; 43-Annular beam; 430-Annular notch; 51-Diverter bracket; 52-Plate body; 53-Mold core; 54-Diverter cone; 55-Inlet of convection channel. Detailed Implementation

[0020] Example 1 like Figure 1 The tube extrusion die shown employs a flow divider support 51. The radial support and positioning of the die core 53 is achieved through several circumferentially arranged plates 52 on the flow divider support 51. However, this design has a drawback: the flow divider support 51 needs to be axially assembled with the flow divider cone 54, which must be directly aligned with the flow channel inlet 55. This results in a misalignment between the relative positions of the flow divider cone and the flow channel inlet 55, leading to a deviation in the concentricity of the die core 53 and the flow channel inlet 55. Consequently, this affects the circumferential consistency of the formed tube wall thickness. Furthermore, because the flow divider support 51 is located behind the flow divider cone 54, the flow channel length from the flow channel inlet 55 to the tube cavity 32 is excessively long, reducing material displacement efficiency and affecting the stability and quality of the molding process.

[0021] And as Figure 2 As shown, the width of the flow channel passing through the flow divider 51 converges gradually until it merges with the tube cavity 32. This flow channel structure results in an excessively low shear rate of the molding material before entering the tube cavity 32, leading to poor material flowability (excessively high viscosity). This, in turn, causes excessively high shear stress during flow, resulting in severe chain breakage of the material's molecular chains, which affects the material's properties.

[0022] Example 2 Combination Figure 3 and Figure 4 The embodiment shown provides a tube extrusion molding die, comprising: The core 1 and the sleeve 2 are provided. The core 1 is disposed inside the sleeve 2. A molding cavity 3 is provided between the core 1 and the sleeve 2. The sleeve 2 has an inlet 201 and an annular outlet 202 at both ends that communicate with the molding cavity 3, respectively. The core 1 includes a conical head 11 and a tube core 12. The tip of the conical head 11 faces the feed inlet 201. The forming cavity 3 includes a feed flow channel cavity 31 and a tube cavity 32. The tube cavity 32 is disposed between the tube core 12 and the sleeve 2. The core section 12 extends axially from the end of the conical head 11 away from the feed inlet 201; The sleeve 2 is provided with a conical cavity 203 that is adapted to at least part of the shape of the conical head 11. The conical cavity 203 is axially abutted against the conical head 11. A number of positioning parts with concave and convex fits are provided between the conical cavity 203 and the conical head 11. The number of positioning parts are circumferentially distributed around the axis of the conical head 11. The feed channel cavity 31 is disposed between the conical head 11 and the sleeve 2. The feed channel cavity 31 includes a plurality of branch channels 310. The plurality of branch channels 310 are evenly distributed in a circle around the axis of the conical head 11, and the positioning part and the branch channels 310 are staggered in the circumferential direction of the distribution. The feed ends of the plurality of branch channels 310 converge and face the feed port 201.

[0023] Based on the above structure, the principle of a tube extrusion molding die is as follows: the raw material is extruded from the feed port 201 into the molding cavity 3, passes through the feed channel cavity 31 and the tube cavity 32, and is continuously extruded from the annular discharge port 202 to form a tube.

[0024] On the one hand, the axial and radial positioning of the sleeve 2 and the core 1 is achieved through the axial contact of the conical cavity 203 and the conical head 11, and the circumferential positioning of the sleeve 2 and the core 1 is achieved through the positioning part. The branch flow channel 310 is uniformly distributed circumferentially between the conical surface of the conical head 11 and the sleeve 2, which can effectively ensure the uniformity of tube forming. Furthermore, the positioning part and the branch flow channel are set on the conical head 11, which not only strengthens the positioning rigidity of the core and the sleeve, but also avoids the multi-stage assembly errors caused by traditional branch support, significantly improving the symmetry of the flow field in the mold and the uniformity of the tube wall thickness.

[0025] On the other hand, compared with the existing extrusion mold such as in Example 1, the structure of the flow divider at one end of the conical head is eliminated, the length of the flow channel is reduced, and the material replacement rate is increased, thus improving the stability and quality of tube forming.

[0026] Combination Figure 6 and Figure 7 As shown, in this embodiment, the branch flow channel 310 is disposed on the conical cavity 203 and the conical head 11. The side of the conical head 11 is divided into several inner positioning conical surfaces 111 by the branch flow channel 310, and the side of the conical cavity 203 is divided into several outer positioning conical surfaces 2011 by the branch flow channel 310. The inner positioning conical surfaces 111 and the outer positioning conical surfaces 2011 abut against each other, and the positioning part is disposed between the inner positioning conical surfaces 111 and the outer positioning conical surfaces 2011. In the direction from the tip to the wide end of the conical head 11, the width of the branch flow channel 310 gradually increases. Adjacent branch flow channels 310 at the wide end of the conical head 11 tend to merge in the circumferential direction, making the flow of the tube molding material (molten adhesive) smoother, reducing unnecessary flow resistance and pressure loss, and improving the overall flow efficiency. Specifically, the positioning part includes a protrusion 112 disposed on the inner positioning conical surface 111 and a recess 2012 disposed on the outer positioning conical surface 2011. A first screw 24 is provided on the sleeve 2, and the front end of the first screw 24 passes through the recess 2012 and is threadedly connected to the protrusion 112.

[0027] Furthermore, in this embodiment, the core 1 also includes a transition core 13 located between the conical head 11 and the core portion 12; The forming cavity 3 also includes an annular transition channel 33 located between the feed channel cavity 31 and the tube cavity 32. The annular transition channel 33 is located between the transition core 13 and the sleeve 2. The annular transition channel 33 includes a stress relief annular cavity 331. In the direction extending from the feed channel cavity 31 to the tube body cavity 32, the width of the stress relief ring cavity 331 in the radial direction first increases, then decreases, and finally tends to match the width of the tube body cavity 32. Furthermore, the radial width of the stress relief ring cavity 331 near the feed channel cavity 31 is smaller than the radial width near the tube body cavity 32. Based on this structure, since the radial width of the stress relief ring cavity 331 near the feed channel cavity 31 is smaller than the radial width near the tube body cavity 32, combined with… Figure 5 As shown, the shear rate of the molding material fluid before entering the tube cavity 32 can be increased, thereby reducing viscosity and increasing flow rate. Furthermore, the molding material fluid entering the stress relief annular cavity 331 can release internal stress, allowing the molecular chains to release stress and stabilize flow behavior, avoiding uneven flow caused by excessive local shearing. The tube molding material (molten adhesive) can achieve a stable and uniform flow state before entering the tube cavity 32, which helps improve the consistency of molding quality.

[0028] In this embodiment, the annular transition channel 33 further includes a confluence annular cavity 332, which is located between the stress relief annular cavity 331 and the feed channel cavity 31. The width of the confluence annular cavity 332 in the radial direction is generally smaller than the width of the stress relief annular cavity 331. The confluence annular cavity 332 can improve the shear rate, enabling effective static mixing of the tube molding material (molten adhesive); simultaneously, it maintains a stable flow rate, ensuring uniform distribution of shear behavior and improving mixing quality.

[0029] In actual production, when the wall thickness of the formed tube is uneven, adjusting the radial position between the sleeve and the core can improve the tube forming quality. However, there are two reasons for uneven tube wall thickness: one is circumferential uneven flow rate in the tube cavity, and the other is radial deviation between the sleeve and the core. However, the shear rate of the forming material (molten adhesive) is low after entering the tube cavity, which leads to an increase in viscosity and makes it difficult to achieve precise flow distribution. It is difficult to simultaneously ensure circumferential uniformity of flow rate and product shape stability.

[0030] Therefore, in this embodiment, in combination with Figure 4 and Figure 8As shown, the sleeve 2 is equipped with a flow regulating ring 4, which includes an elastic ring 42 located radially outside the confluence ring cavity 332. The sleeve 2 has several extrusion members 23 that abut against the elastic ring 42. Each extrusion member 23 corresponds to a branch flow channel 310, with each extrusion member 23 positioned directly opposite the corresponding branch flow channel 310 in the direction extending outward from the confluence ring cavity 332. The extrusion members 23 are adjustable and movable on the sleeve 2 to compress the elastic ring 42 in the radial direction. Specifically, the extrusion member 23 is an adjusting screw that radially penetrates the sleeve 2, and the adjusting screw is threadedly connected to the side wall of the sleeve 2. By adjusting the extrusion members 23 to compress the elastic ring 42 in the radial direction, the flow rate entering the flow regulating ring 4 from each branch flow channel 310 can be independently adjusted. By adjusting the extrusion members 23 to apply compression to the preset deformation zone of the flow regulating ring 4, controllable changes in the local flow channel cross-section are achieved, resulting in a precise flow rate adjustment and dynamic flow balance adjustment. Therefore, on the one hand, setting up the manifold cavity 332 can increase the shear rate of the tube molding material (molten adhesive) before it enters the tube cavity 32. On the other hand, setting up the flow regulating ring 4 outside the manifold cavity 332 allows the molten adhesive to be adjusted in a state of lower viscosity and better fluidity, significantly improving the sensitivity and accuracy of flow control. Furthermore, the flow regulating ring 4 is designed with its shape according to the number of flow branches, allowing for independent or regional adjustment for each flow branch channel, thereby improving the problem of uneven flow distribution in multi-channel systems.

[0031] Specifically, the elastic ring 42 includes rigid bodies 421 and spring pieces 422 that are interleaved in the circumferential direction. Each spring piece 422 corresponds to a pressing member 23, and the pressing member 23 abuts against the spring piece 422. The number of rigid bodies 421, spring pieces 422, and corresponding pressing members 23 are 5. Further, in this embodiment, the flow regulating ring 4 also includes a support ring 41, which is located at one axial end of the elastic ring 42. An annular notch 430 is provided on the outer surface of the flow regulating ring 4. The flow regulating ring 4 also includes an annular beam 43 located radially inside the annular notch 430. The annular beam 43 and the annular notch 430 are located between the support ring 41 and the elastic ring 42 in the axial direction. The support ring 41 and the elastic ring 42 are integrally connected to the annular beam 43. The support ring 41 and the rigid body 421 are used to maintain the overall rigidity of the flow regulating ring 4, ensure the positional accuracy during installation, and improve service life. During the deformation of the spring 422, the support ring 41 will not deform. Furthermore, the setting of the ring beam 43 improves the effectiveness of the spring 422's outward reset, which can prevent material jamming caused by the deformation of the spring 422.

[0032] In this embodiment, the sleeve 2 includes a feed sleeve 21 and a discharge sleeve 22, which are detachably connected. The feed port 201 and the conical cavity 203 are provided on the feed sleeve 21, and the annular discharge port 202 is provided on the discharge sleeve 22. The feed sleeve 21 and the discharge sleeve 22 abut against each other axially. An annular groove 204 is provided between the feed sleeve 21 and the discharge sleeve 22 axially. The flow regulating ring 4 is embedded in the annular groove 204. The rigid body 421 and the support ring 41 abut against the side wall of the annular groove 204 radially upward.

[0033] In this embodiment, the stress relief ring cavity 331 is located on the radial inner side of the support ring 41, the ring groove 204 is provided on the feed sleeve 21, the end of the ring groove 204 near the discharge sleeve 22 is open, and the two axial ends of the flow regulating ring 4 are tightly abutted in the axial direction with the side wall of the ring groove 204 and the end face of the discharge sleeve 22 to effectively improve the sealing performance.

[0034] In this embodiment, combined with Figure 4 and Figure 6 As shown, the discharge sleeve 22 extends radially outward from one end near the feed sleeve 21 and is provided with a positioning ring 221. The feed sleeve 21 is provided with a groove 211 for receiving the positioning ring 221. The positioning ring 221 is adapted to the groove 211 and is installed inside the groove 211. The sleeve 2 also includes a limiting ring 25, which is sleeved on the discharge sleeve 22. The limiting ring 25 and the feed sleeve 21 are axially detachably connected by a second screw 26. The upper limit of the positioning ring 221 is located between the limiting ring 25 and the groove 211.

[0035] Specifically, a set of third screws 27 is provided on the side wall of the feed sleeve 21. The set of third screws 27 are evenly distributed in the circumferential direction and penetrate the side wall of the groove 211, abutting against the radial outer side of the positioning ring 221. By adjusting the third screws 27, the radial position between the discharge sleeve 22 and the core part 12 can be adjusted to achieve the adjustment of the uniformity of the formed tube wall thickness.

[0036] The technical principles of the present invention have been described above with reference to specific embodiments. These descriptions are merely for explaining the principles of the invention and should not be construed as limiting the scope of protection of the invention in any way. Based on this explanation, those skilled in the art can conceive of other specific embodiments of the invention without creative effort, and these embodiments will all fall within the scope of protection of the present invention.

Claims

1. A tube extrusion molding die, comprising: The core (1) and the sleeve (2) are provided. The core (1) is set inside the sleeve (2). A molding cavity (3) is provided between the core (1) and the sleeve (2). The sleeve (2) is provided with a feed port (201) and an annular discharge port (202) at both ends, which are connected to the molding cavity (3). The core (1) includes a conical head (11) and a tube core (12). The tip of the conical head (11) faces the feed inlet (201). The forming cavity (3) includes a feed channel cavity (31) and a tube cavity (32). The tube cavity (32) is located between the tube core (12) and the sleeve (2). Its features are: The sleeve (2) is provided with a conical cavity (203) that is adapted to at least part of the shape of the conical head (11). The conical cavity (203) and the conical head (11) are axially abutted together. A number of positioning parts with concave-convex fit are provided between the conical cavity (203) and the conical head (11). The number of positioning parts are circumferentially distributed around the axis of the conical head (11). The feed channel cavity (31) is located between the conical head (11) and the sleeve (2). The feed channel cavity (31) includes several branch channels (310). The several branch channels (310) are evenly distributed in a circle around the axis of the conical head (11), and the positioning part and the branch channels (310) are staggered in the circumferential direction of the distribution. The feed ends of the several branch channels (310) converge and face the feed inlet (201). The branch channels (310) are located on the conical cavity (203) and the conical head (11). The side of the conical head (11) is covered by the branch channels (310). The cone cavity (203) is divided into several inner positioning cone surfaces (111), and the side of the cone cavity (203) is divided into several outer positioning cone surfaces (2011) by the branch flow channel (310). The inner positioning cone surface (111) and the outer positioning cone surface (2011) abut and cooperate. The positioning part is set between the inner positioning cone surface (111) and the outer positioning cone surface (2011). In the direction from the tip to the wide end of the cone head (11), the width of the branch flow channel (310) increases from small to large. The branch flow channels (310) adjacent to each other at the wide end of the cone head (11) tend to merge in the circumferential direction.

2. The tube extrusion molding die according to claim 1, characterized in that: The core (1) also includes a transition core (13) located between the conical head (11) and the core section (12); The forming cavity (3) further includes an annular transition channel (33) located between the feed channel cavity (31) and the tube cavity (32). The annular transition channel (33) is located between the transition core (13) and the sleeve (2). The annular transition channel (33) includes a stress relief annular cavity (331). In the direction of extension from the feed channel cavity (31) to the tube cavity (32), the width of the stress relief ring cavity (331) in the radial direction first increases and then decreases, eventually becoming consistent with the width of the tube cavity (32). The radial width of the stress relief ring cavity (331) near the feed channel cavity (31) is smaller than the radial width near the tube cavity (32).

3. The tube extrusion molding die according to claim 2, characterized in that: The annular transition channel (33) further includes a confluence annular cavity (332), which is located between the stress relief annular cavity (331) and the feed channel cavity (31). In the radial direction, the width of the confluence annular cavity (332) is generally smaller than the width of the stress relief annular cavity (331).

4. The tube extrusion molding die according to claim 3, characterized in that: The sleeve (2) is provided with a flow regulating ring (4), which includes an elastic ring (42). The elastic ring (42) is located on the radial outer side of the confluence ring cavity (332). The sleeve (2) is provided with a number of extrusion members (23) that abut against the elastic ring (42). The extrusion members (23) correspond one-to-one with the branch flow channels (310). The position of each extrusion member (23) is directly opposite to the corresponding branch flow channel (310) in the direction of extension towards the confluence ring cavity (332). The extrusion members (23) can be adjusted and moved on the sleeve (2) to extrude the elastic ring (42) in the radial direction.

5. The tube extrusion molding die according to claim 4, characterized in that: The elastic ring (42) includes rigid bodies (421) and spring pieces (422) that are interleaved in the circumferential direction. The spring pieces (422) correspond one-to-one with the extruder (23), and the extruder (23) abuts against the spring pieces (422).

6. The tube extrusion molding die according to claim 4, characterized in that: The flow regulating ring (4) also includes a support ring (41), which is located at one axial end of the elastic ring (42). The outer surface of the flow regulating ring (4) is provided with an annular notch (430). The flow regulating ring (4) also includes an annular beam (43) located radially inside the annular notch (430). The annular beam (43) and the annular notch (430) are located between the support ring (41) and the elastic ring (42) in the axial direction. The support ring (41) and the elastic ring (42) are integrally connected with the annular beam (43).

7. A tube extrusion molding die according to claim 6, characterized in that: The sleeve (2) includes a feed sleeve (21) and a discharge sleeve (22). The feed sleeve (21) and the discharge sleeve (22) are detachably connected. The feed port (201) and the cone cavity (203) are provided on the feed sleeve (21), and the annular discharge port (202) is provided on the discharge sleeve (22). The feed sleeve (21) and the discharge sleeve (22) abut against each other axially. An annular groove (204) is provided between the feed sleeve (21) and the discharge sleeve (22) axially. The flow regulating ring (4) is embedded in the annular groove (204). The rigid body (421) and the support ring (41) abut against the side wall of the annular groove (204) radially upward.

8. The tube extrusion molding die according to claim 7, characterized in that: The stress relief ring cavity (331) is located on the radial inner side of the support ring (41). The ring groove (204) is set on the feed sleeve (21). The end of the ring groove (204) near the discharge sleeve (22) is open. The two axial ends of the flow regulating ring (4) are in close axial contact with the side wall of the ring groove (204) and the end face of the discharge sleeve (22).

9. A tube extrusion molding die according to claim 7, characterized in that: The discharge sleeve (22) extends radially outward from one end near the feed sleeve (21) and is provided with a positioning ring (221). The feed sleeve (21) is provided with a groove (211) for receiving the positioning ring (221). The positioning ring (221) is adapted to the groove (211) and is installed in the groove (211). The sleeve (2) also includes a limiting ring (25). The limiting ring (25) is sleeved on the discharge sleeve (22). The limiting ring (25) and the feed sleeve (21) are axially detachably connected. The upper limit of the positioning ring (221) is located between the limiting ring (25) and the groove (211).

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