Die head special for multi-layer co-extrusion cable

Abstract

The utility model relates to the technical field of cable die heads, in particular to a die head special for a multi-layer co-extrusion cable, which comprises a die head shell, a plurality of die sleeves are detachably mounted in the die head shell, and a plurality of runners for circulating insulating materials in a molten state are formed in each die sleeve in an annular array manner. The die sleeve comprises a first die sleeve body installed in the die head shell in a threaded mode, a second die sleeve body is installed on one side of the first die sleeve body in a threaded mode, and a third die sleeve body is installed on one side of the second die sleeve body in a threaded mode. The runner is fixedly provided with a sealing ring at the joint of each die sleeve, so that a molten insulating material is effectively prevented from leaking from the joint of the die sleeve, and a through hole is formed in the center of each die sleeve in a penetrating manner, so that a cable core wire can pass through the through hole; a fixing plate used for further fixing the die sleeve is further installed in the die head shell in a sliding mode.

Description

Technical Field

[0001] This utility model relates to the field of cable die head technology, and in particular to a special die head for multi-layer co-extruded cables. Background Technology

[0002] Multi-layer co-extrusion technology is an advanced plastics processing technology that uses multiple extruders to feed materials, forming a multi-layered molten preform through a multi-layered composite die, which is then blow-molded or extruded into multi-layered plastic products. In the cable manufacturing industry, multi-layer co-extrusion technology is widely used to produce cables with multi-layered insulation structures.

[0003] Chinese Patent CN222328986U discloses a multi-layer co-extrusion extruder head for cables. This utility model slides multiple molds around the outside of the die core, and uses a drive component to drive relative movement between adjacent molds, thereby automatically disassembling the molds outside the die core one by one. It also has a sealing component to seal between adjacent molds to prevent leakage in the material conveying channel. Compared with the prior art, it can disassemble the molds more efficiently and facilitate mold maintenance.

[0004] Due to the complex internal structure of the die head, inconvenient disassembly, poor sealing, and uneven distribution of the insulation layer, problems such as easy leakage of insulation material and unstable insulation layer quality occur during cable production. In view of this, a special die head for multi-layer co-extrusion cables is provided. Utility Model Content

[0005] The main purpose of this utility model is to provide a special die head for multilayer co-extrusion cables, so as to solve the problems of easy leakage of insulation material and unstable insulation quality in cable production when the die head has a complex internal structure, is inconvenient to disassemble, has poor sealing performance, and has uneven insulation layer distribution.

[0006] To achieve the above objectives, according to one aspect of the present invention, a special die head for multilayer co-extrusion cables is provided, including a die head housing, wherein a plurality of die sleeves are detachably installed inside the die head housing, and each die sleeve has a plurality of channels for the flow of molten insulating material in a circular array, wherein a sealing ring is fixedly provided at the connection of each die sleeve, and a through hole is provided through the center of each die sleeve for the cable core wire to pass through, and a fixing plate for further fixing the die sleeves is also slidably installed inside the die head housing;

[0007] The mold sleeve includes a first mold sleeve threadedly installed inside the mold head housing, a second mold sleeve threadedly installed on one side of the first mold sleeve, a third mold sleeve threadedly installed on one side of the second mold sleeve, and the fixing plate tightly fitting the side wall of the third mold sleeve.

[0008] Furthermore, both the mold head housing and the first mold sleeve are provided with multiple annularly distributed flow channel structures, each flow channel structure including a first flow channel, a second flow channel, and a third flow channel; similarly, the second mold sleeve is also provided with multiple annularly distributed flow channel structures, each flow channel structure including a first flow channel and a second flow channel; the third mold sleeve is also provided with multiple annularly distributed flow channel structures, each flow channel structure including a first flow channel.

[0009] Furthermore, the mold head housing has a plurality of first slots arranged in a ring array inside, each of which is connected to each flow channel. The mold head housing also has an installation groove arranged in a ring shape, and the mold head housing also has an annular cavity filled with a refrigerant.

[0010] Furthermore, the first mold sleeve has several second slots arranged in a ring array at both ends, and the second slots are respectively connected to each flow channel. A fixing ring is fixedly connected to one end of the first mold sleeve, and an expansion ring is fixedly connected to one end of the fixing ring. The fixing ring is threaded in the mounting groove. Similarly, the second mold sleeve is threaded on one side of the first mold sleeve, and the third mold sleeve is threaded on one side of the second mold sleeve.

[0011] Furthermore, one end of the sealing ring is inserted into the first slot, and the other end of the sealing ring is fixedly installed in the second slot near the fixing ring. Similarly, a sealing ring is inserted into the flow channel connection between the second mold sleeve and the first mold sleeve, and a sealing ring is inserted into the flow channel connection between the third mold sleeve and the second mold sleeve.

[0012] Furthermore, the diameter of the through hole at the center of the first mold sleeve is larger than the diameter of the through hole at the center of the second mold sleeve, the diameter of the through hole at the center of the second mold sleeve is larger than the diameter of the through hole at the center of the third mold sleeve, and each mold sleeve has several annular grooves that communicate with the through holes.

[0013] Furthermore, the first mold sleeve has several branch channels arranged in a ring array. One end of each branch channel is connected to the third flow channel, and the other end is connected to the annular groove in the first mold sleeve. The second flow channel and the first flow channel have the same structure.

[0014] Furthermore, a through groove is provided at the center of the fixing plate, through which the cable core wire passes. A sliding groove is symmetrically provided on the mold head housing, and a screw hole is provided on the mold head housing near one end of the sliding groove. A slider is symmetrically fixedly connected to the outer wall of the fixing plate, and a screw is threaded through the slider. The slider is slidably installed in the sliding groove, and one end of the screw is threaded in the screw hole.

[0015] Compared with the prior art, the present invention has the following beneficial effects:

[0016] 1. In this multi-layer co-extrusion cable die head, the die sleeve is installed inside the die head housing by threads. This detachable installation structure facilitates the replacement and maintenance of the die sleeve, and also makes it easy to adjust the number and type of die sleeves according to production needs to adapt to the production of cables of different specifications and materials. The flow channel is located at the connection of each die sleeve and a sealing ring is fixedly installed, which effectively prevents the molten insulation material from leaking from the die sleeve connection, ensuring the cleanliness of the production environment and the integrity of the insulation layer.

[0017] 2. In this multi-layer co-extrusion die for cables, the cavity inside the die housing is filled with coolant. When the cable core passes through the die, it is cooled by the coolant, which helps to reduce the temperature of the cable core and promotes the rapid solidification of the molten insulation material that has just been laid on its surface, thus improving production efficiency. A through slot is provided in the center of the fixing plate, through which the cable core passes, providing stable support. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the overall structure of the multilayer co-extruded cable die head in a preferred embodiment of this utility model;

[0019] Figure 2 This is a cross-sectional view of the die head for multilayer co-extruded cables in a preferred embodiment of this utility model;

[0020] Figure 3 This is a cross-sectional view of the mold head housing in a preferred embodiment of the present invention;

[0021] Figure 4 This is a preferred embodiment of the present invention. Figure 3 Enlarged schematic diagram of the structure at point A in the middle;

[0022] Figure 5 This is a cross-sectional view of the first mold in a preferred embodiment of the present invention;

[0023] Figure 6 This is a preferred embodiment of the present invention. Figure 5 Enlarged schematic diagram of the structure at point B;

[0024] Figure 7 This is a schematic diagram of the overall structure of the fixing plate in a preferred embodiment of the present invention.

[0025] Illustration:

[0026] 1. Mold head housing; 11. Slide groove; 12. Screw hole; 13. Cavity; 14. First slot; 15. Mounting slot;

[0027] 2. First mold sleeve; 7. Third flow channel; 22. Through hole; 23. Retaining ring; 28. Expansion ring; 24. Branch channel; 25. Ring groove; 26. Second slot;

[0028] 3. Second mold sleeve; 8. Second runner; 4. Third mold sleeve; 9. First runner;

[0029] 5. Fixing plate; 51. Through groove; 52. Slider; 53. Screw; 6. Sealing ring. Detailed Implementation

[0030] To further illustrate the technical means and effects adopted by this utility model in order to achieve the intended utility model purpose, the following detailed description of the specific implementation methods, structure, features and effects of this utility model is provided in conjunction with the accompanying drawings and preferred embodiments.

[0031] Please see Figures 1-7 As shown, the purpose of this embodiment is to provide a special die head for multilayer co-extrusion cables, including a die head housing 1. Several die sleeves are detachably installed inside the die head housing 1. Each die sleeve has several channels arranged in a ring array for the flow of molten insulating material. A sealing ring 6 is fixedly installed at the connection of each die sleeve. A through hole 22 is opened through the center of each die sleeve for the cable core wire to pass through. A fixing plate 5 for further fixing the die sleeves is also slidably installed inside the die head housing 1.

[0032] The mold sleeve includes a first mold sleeve 2 threadedly installed inside the mold head housing 1, a second mold sleeve 3 threadedly installed on one side of the first mold sleeve 2, a third mold sleeve 4 threadedly installed on one side of the second mold sleeve 3, and the fixing plate 5 tightly fitting the side wall of the third mold sleeve 4.

[0033] The die housing 1 is mounted on the extruder, and the flow channel is connected to the extruder;

[0034] Both the die head housing 1 and the first die sleeve 2 are provided with multiple flow channel structures arranged in a ring. Each flow channel structure includes a first flow channel 9, a second flow channel 8, and a third flow channel 7. The first flow channel 9, the second flow channel 8, and the third flow channel 7 are located on the same straight line. The first flow channel 9, the second flow channel 8, and the third flow channel 7 all penetrate through the die head housing 1 and the first die sleeve 2.

[0035] The second mold 3 also has multiple flow channel structures arranged in a ring. Each flow channel structure includes a first flow channel 9 and a second flow channel 8. The first flow channel 9 and the second flow channel 8 are located on the same straight line and both the first flow channel 9 and the second flow channel 8 penetrate the second mold 3.

[0036] The third mold 4 also has multiple flow channel structures arranged in a ring, each flow channel structure including a first flow channel 9, which penetrates the third mold 4.

[0037] The molten insulating material can flow from the outside of the die housing 1 into the first flow channel 9, the second flow channel 8, and the third flow channel 7, and then wrap around the cable core wire.

[0038] The first flow channel 9 is used to initially wrap the cable core with a cross-linked polyethylene insulation layer, which has low dielectric loss, excellent electrical breakdown resistance, and good heat resistance, cold resistance, and chemical stability, providing reliable electrical protection and long-term stability. The second flow channel 8 is used to further wrap the cable core with a polyvinyl chloride insulation layer, which has good insulation, heat resistance, and chemical resistance, and is also malleable and easy to process, providing the cable with additional mechanical strength and abrasion resistance. The third flow channel 7 is used to finally wrap the cable core with a polyvinyl chloride insulation layer, similar to the PVC in the second flow channel 8, but the PVC in the third flow channel 7 focuses more on abrasion resistance and anti-aging performance, serving as the cable's sheath layer to protect the cable from damage from the external environment.

[0039] The mold head housing 1 has a plurality of first slots 14 arranged in a ring array inside, and the first slots 14 are respectively connected to each flow channel. The mold head housing 1 also has an installation groove 15, which is ring-shaped. The mold head housing 1 also has an annular cavity 13, which is filled with a refrigerant. The annular mold head housing 1 has a liquid inlet communicating with the cavity 13 for injecting the refrigerant into the cavity 13. Similarly, the mold head housing 1 also has a liquid outlet communicating with the cavity 13 for discharging the refrigerant from the cavity 13. Under normal use, both the liquid inlet and the liquid outlet of the mold head are equipped with sealing plugs.

[0040] The first mold sleeve 2 has several second slots 26 arranged in a ring array at both ends. Each second slot 26 is connected to a flow channel. A fixing ring 23 is fixedly connected to one end of the first mold sleeve 2, and an expansion ring 28 is fixedly connected to one end of the fixing ring 23. The fixing ring 23 is threaded in the mounting groove 15, that is, the fixing ring 23 has external threads and the mounting groove 15 has internal threads, which effectively prevents the molten insulation material from leaking from the connection between the two mold sleeves when the cable core wire passes through. When the fixing ring 23 is threaded in the mounting groove 15, the diameter of the expansion ring 28 is larger than the inner diameter of the mounting groove 15 to provide an interference fit, thereby tightly fitting the inner wall of the mounting groove 15, which not only improves the stability of the connection, but also effectively prevents the leakage of molten insulation material. Similarly, the second mold sleeve 3 is threaded on one side of the first mold sleeve 2, and the third mold sleeve 4 is threaded on one side of the second mold sleeve 3.

[0041] One end of the sealing ring 6 is inserted into the first slot 14, and the other end of the sealing ring 6 is fixedly installed in the second slot 26 near the fixed ring 23. Similarly, the sealing ring 6 is inserted into the flow channel connection between the second mold sleeve 3 and the first mold sleeve 2, and the sealing ring 6 is inserted into the flow channel connection between the third mold sleeve 4 and the second mold sleeve 3.

[0042] During installation, the retaining ring 23 of the first mold sleeve 2 is rotated and threaded into the mounting groove 15. During this process, the sealing ring 6 on it is compressed by the inner wall of the mold head housing 1 and contracts. As the retaining ring 23 rotates and goes deeper into the mounting groove 15, the sealing ring 6 will gradually align with the first slot 14, and the retaining ring 23 will be completely installed in the mounting groove 15. At this time, the sealing ring 6 will lose the compression pressure and recover, filling the gap of the first slot 14. The sealing ring 6 effectively prevents the leakage of molten insulating material from the flow channel joint. For the second mold sleeve 3 and the third mold sleeve 4, the above installation process needs to be repeated to ensure the sealing of the entire mold head system. It is worth noting that the sealing ring 6 is a high temperature resistant sealing ring. When the molten insulating material flows through the sealing ring 6, it will not cause the sealing ring 6 to deform or be damaged.

[0043] The diameter of the through hole 22 at the center of the first mold sleeve 2 is larger than the diameter of the through hole 22 at the center of the second mold sleeve 3, and the diameter of the through hole 22 at the center of the second mold sleeve 3 is larger than the diameter of the through hole 22 at the center of the third mold sleeve 4. This is because when the cable core moves from the third mold sleeve 4 to the first mold sleeve 2, it will pass through the flow channels of each mold sleeve in sequence. As the diameter of the through hole 22 of each mold sleeve gradually increases, the cable core will be wrapped with a new layer of insulating material when passing through each mold sleeve, thus making the insulation layer gradually thicker. In addition, each mold sleeve has several annular grooves 25, which are connected to the through hole 22.

[0044] The first mold sleeve 2 has several branch channels 24 arranged in a ring array. One end of each branch channel 24 is connected to the third flow channel 7, and the other end is connected to the annular groove 25 in the first mold sleeve 2. This ensures that the insulating material injected from the third flow channel 7 can be evenly distributed into each branch channel 24 and further flow into the annular groove 25. The second flow channel 8 and the first flow channel 9 have the same structure. After passing through each mold sleeve, the insulating material injected into the first flow channel 9 flows into the annular groove 25 opened in the third mold sleeve 4 through the branch channels 24. They will form a uniform insulating layer in the annular groove 25 and be evenly laid on its surface as the cable core wire gradually moves, thus distributing more evenly around the cable core wire.

[0045] Furthermore, the cavity 13 inside the die housing 1 is preferably filled with water-based coolant or liquid nitrogen. When the cable core wire passes through the die, it comes into contact with the wall of the cavity 13 and is thus cooled by the coolant, which helps to reduce the temperature of the cable core wire and promotes the rapid solidification of the molten insulation material that has just been laid on its surface. This not only improves production efficiency but also helps to reduce defects in the insulation layer and improve cable quality. In addition, the outside of the cavity 13 is made of heat-insulating material to prevent the molten insulation material in the flow channel from solidifying prematurely due to the coolant filling the cavity 13.

[0046] A through groove 51 is provided through the center of the fixing plate 5, through which the cable core wire passes. A sliding groove 11 is symmetrically provided on the die head housing 1, and a screw hole 12 is provided on the die head housing 1 near the sliding groove 11. A slider 52 is symmetrically fixedly connected to the outer wall of the fixing plate 5, and a screw 53 is threaded through the slider 52. The slider 52 is slidably installed in the sliding groove 11, and one end of the screw 53 is threaded in the screw hole 12. The screw 53 passes through the slider 52 and is screwed into the screw hole 12 to lock the position of the fixing plate 5. By controlling the position of the fixing plate 5, the stability and safety of the cable core wire during the processing are ensured.

[0047] In practical use, the fixing ring 23 of the first mold sleeve 2 is aligned with the mounting groove 15 of the mold head housing 1 and rotated and threaded into the mounting groove 15 of the mold head housing 1. During this process, the sealing ring 6 on it is compressed by the inner wall of the mold head housing 1 and contracts. As the fixing ring 23 rotates and goes deeper into the mounting groove 15, the sealing ring 6 gradually aligns with the first slot 14, and the fixing ring 23 is completely installed in the mounting groove 15. At this time, the sealing ring 6 loses the compression pressure and returns to its original shape, filling the gap in the first slot 14. The second mold sleeve 3 and the third mold sleeve 4 are then threaded onto the adjacent mold sleeves in sequence. The movable fixing plate 5 causes the slider 52 to slide in the groove 11, so that the fixing plate 5 is tightly attached to the side wall of the third mold sleeve 4, and the slider 52 is fixed in the screw hole 12 by the screw 53 to fix the position of the plate 5; the cable core wire is inserted into the through groove 51 of the fixing plate 5, and the cable core wire passes through the through holes 22 of the third mold sleeve 4, the second mold sleeve 3 and the first mold sleeve 2 in sequence. During this process, the extruder is started, so that the molten insulating material is evenly wrapped around the cable core wire through each flow channel. When the cable core wire passes through the die head housing 1, it is cooled by the coolant in the cavity 13, which promotes the rapid solidification of the insulating material.

[0048] The above are merely preferred embodiments of the present utility model and are not intended to limit the present utility model in any way. Although the present utility model has been disclosed above with reference to preferred embodiments, it is not intended to limit the present utility model. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present utility model. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present utility model without departing from the scope of the present utility model shall still fall within the scope of the present utility model.

Claims

1. Multilayer co-extrusion cable special die comprising a die housing (1), characterized in that, The die head housing (1) is detachably installed with several die sleeves. Each die sleeve has several channels arranged in a ring array for the flow of molten insulating material. Each channel is fixedly provided with a sealing ring (6) at the connection of each die sleeve. Each die sleeve has a through hole (22) at its center for the cable core wire to pass through. The die head housing (1) is also slidably installed with a fixing plate (5) for further fixing the die sleeves. The mold sleeve includes a first mold sleeve (2) threadedly installed in the mold head housing (1), a second mold sleeve (3) threadedly installed on one side of the first mold sleeve (2), a third mold sleeve (4) threadedly installed on one side of the second mold sleeve (3), and the fixing plate (5) tightly fitting the side wall of the third mold sleeve (4).

2. The multi-layer co-extrusion cable dedicated die according to claim 1, characterized in that, The mold head housing (1) and the first mold sleeve (2) are each provided with multiple flow channel structures arranged in a ring, each flow channel structure including a first flow channel (9), a second flow channel (8), and a third flow channel (7); similarly, the second mold sleeve (3) is also provided with multiple flow channel structures arranged in a ring, each flow channel structure including a first flow channel (9) and a second flow channel (8); the third mold sleeve (4) is also provided with multiple flow channel structures arranged in a ring, each flow channel structure including a first flow channel (9).

3. The multi-layer co-extrusion cable dedicated die according to claim 1, characterized in that, The mold head housing (1) has a plurality of first slots (14) arranged in a ring array inside, and the first slots (14) are connected to each flow channel respectively. The mold head housing (1) also has an installation groove (15) arranged in a ring, and the mold head housing (1) also has an annular cavity (13) arranged in a ring, which is filled with a refrigerant.

4. The multi-layer co-extrusion cable dedicated die according to claim 3, characterized in that, The first mold sleeve (2) has several second slots (26) arranged in a ring array at both ends. The second slots (26) are connected to each flow channel respectively. A fixing ring (23) is fixedly connected to one end of the first mold sleeve (2), and an expansion ring (28) is fixedly connected to one end of the fixing ring (23). The fixing ring (23) is threaded in the mounting groove (15). Similarly, the second mold sleeve (3) is threaded on one side of the first mold sleeve (2), and the third mold sleeve (4) is threaded on one side of the second mold sleeve (3).

5. The multi-layer co-extrusion cable dedicated die according to claim 4, characterized in that, One end of the sealing ring (6) is inserted into the first slot (14), and the other end of the sealing ring (6) is fixed in the second slot (26) near the fixed ring (23). Similarly, the sealing ring (6) is inserted into the flow channel connection between the second mold sleeve (3) and the first mold sleeve (2), and the sealing ring (6) is inserted into the flow channel connection between the third mold sleeve (4) and the second mold sleeve (3).

6. The multi-layer co-extrusion cable dedicated die according to claim 2, characterized in that, The diameter of the through hole (22) at the center of the first mold sleeve (2) is larger than the diameter of the through hole (22) at the center of the second mold sleeve (3), the diameter of the through hole (22) at the center of the second mold sleeve (3) is larger than the diameter of the through hole (22) at the center of the third mold sleeve (4), and each mold sleeve has several annular grooves (25) which are connected to the through holes (22).

7. The multi-layer co-extrusion cable dedicated die according to claim 6, characterized in that, The first mold (2) has several branch channels (24) arranged in a ring array. One end of the branch channel (24) is connected to the third flow channel (7), and the other end is connected to the ring groove (25) in the first mold (2). The second flow channel (8) and the first flow channel (9) have the same structure.

8. The multi-layer co-extrusion cable dedicated die according to claim 1, characterized in that, A through groove (51) is provided through the center of the fixing plate (5), through which the cable core wire passes. A sliding groove (11) is symmetrically provided on the mold head housing (1), and a screw hole (12) is provided on one end of the mold head housing (1) near the sliding groove (11). A slider (52) is symmetrically fixedly connected to the outer wall of the fixing plate (5), and a screw (53) is threaded through the slider (52). The slider (52) is slidably installed in the sliding groove (11), and one end of the screw (53) is threaded in the screw hole (12).

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