Variable aperture extrusion die for multi-core conductor and extrusion device

Abstract

The application relates to the technical field of cable manufacturing, in particular to a variable-aperture extruding die for a multi-core conductor and an extruding device, which comprises an outer die body, the front end of the outer die body is conical, and the rear end is provided with a variable diameter; an inner core body is threadedly connected in the outer die body, the front end of the inner core body is provided with a first variable-diameter pipe, a second variable-diameter pipe and a straight elastic wire supporting pipe which are connected in sequence, the straight elastic wire supporting pipe is an elastic pipe, and a plurality of long grooves parallel to the axis of the outer die body are arranged on the straight elastic wire supporting pipe; in normal operation, the straight elastic wire supporting pipe is connected with the inner wall of the outer die body; when the multi-core conductor is connected, the straight elastic wire supporting pipe is separated from the inner wall of the outer die body. The elastic spring sheet of the straight elastic wire supporting pipe is used to realize free expansion of the aperture, so that the pain point that the conductor is too large to smoothly pass through the die due to the head-to-tail connection between different discs of the multi-core conductor can be solved, and the continuous production efficiency and material utilization rate of the multi-core conductor cable are greatly improved.

Description

Technical Field

[0001] This invention relates to the field of cable manufacturing technology, specifically to a variable aperture extrusion mold and extrusion apparatus for multi-core conductors. Background Technology

[0002] In cable manufacturing enterprises, due to the unstable shape of the conductor structure during the extrusion production of Category 2 and Category 5 multi-core conductors, manufacturers generally use fusion splicing or twisting to connect the ends of two conductor coils in order to reduce material consumption and ensure continuous production.

[0003] Chinese Patent CN121447848A discloses a reinforced cable extrusion mold structure and cable for lifting equipment, belonging to the technical field of injection molding. The reinforced cable extrusion mold structure for lifting equipment includes a core unit, a sleeve unit, and two adjustment units. The core unit includes two core seats and a connecting structure between the two core seats, which is used to adjust the distance between the two core seats. The sleeve unit includes a cover with a receiving cavity, and the cover also has adjustment grooves corresponding to the core seats and a through groove connecting the two adjustment grooves. The adjustment units are correspondingly arranged in the adjustment grooves. The adjustment unit includes a turntable in the adjustment groove, multiple outer arc plates spaced apart on the outer periphery of the turntable, and a drive structure connected to the turntable. The outer arc plates have openings that align with the through grooves. The drive structure is used to adjust the position of the arc plates so that different outer arc plates align with the through grooves.

[0004] Chinese Patent CN121716291A discloses an elliptical extrusion mold with eccentricity compensation function, applied to the production process of special cables. The processing method of the elliptical extrusion mold includes the following steps: S1: Preparation of mold body blank, determining the basic size parameters of the mold body according to the molding requirements of the insulation layer of special cables; S2: Calculation of eccentricity compensation parameters, calculating the pre-deformation compensation parameters of the elliptical mold based on the conductor diameter, target thickness of the insulation layer, melt flow characteristics of the extruded material, and material offset law under gravity of the special cable. This can fundamentally offset the uneven flow of extruded material caused by gravity, significantly improve the concentricity of the insulation layer of special cables, solve the insulation layer eccentricity defect caused by neglecting the influence of gravity in traditional mold processing, and ensure the electrical insulation performance and structural stability of special cables.

[0005] However, due to the limitation of the inner diameter of the die core, the joint of Category 2 and Category 5 multi-core conductors cannot pass smoothly through the die head in more than 90% of cases. This leads to the multi-core conductor getting stuck and breaking inside the die head, which not only affects production efficiency but also results in significant material waste. Therefore, how to provide an extrusion die with an expandable orifice diameter at normal production speed has become an urgent problem to be solved. Summary of the Invention

[0006] To address the problem in existing technologies where the splicing joints of multi-core conductors cannot pass smoothly during the insulation extrusion process, this invention provides a variable aperture extrusion die and extrusion device for multi-core conductors, which can quickly handle multi-core bundles of wire, allowing the stranded wires to pass smoothly through the die head after splicing.

[0007] This invention is achieved through the following technical solution: A variable-aperture extrusion mold for multi-core conductors, with the conductor's forward direction as the front, includes an outer mold body. The front end of the outer mold body is tapered, and the rear end is configured with a variable diameter. An inner core body is threadedly connected inside the outer mold body. The front end of the inner core body is sequentially connected to a first variable-diameter tube, a second variable-diameter tube, and a straight elastic bearing tube. The outer diameters of both the first and second variable-diameter tubes gradually decrease, the inner diameter of the first variable-diameter tube gradually decreases, and the inner diameter of the second variable-diameter tube remains constant. The inner diameter of the second variable-diameter tube is the same as the inner diameter of the straight elastic bearing tube. The outer diameter of the straight elastic bearing tube is equal to the minimum outer diameter of the second variable-diameter tube. The straight elastic bearing tube is cut to form multiple spaced elastic arc plates, and the elastic arc plates are age-hardened to form a certain outward expansion angle. The inner wall of the outer mold body is threadedly connected to the outer wall of the straight elastic bearing tube. During normal operation, the straight elastic conduit is connected to the inner wall of the outer mold; when the multi-core conductor is being joined, the straight elastic conduit separates from the inner wall of the outer mold.

[0008] Preferably, a transition section is provided at the internal connection between the first reducing pipe and the second reducing pipe.

[0009] Preferably, the transition section is rounded.

[0010] Preferably, the angle α between the first reducing tube and the central axis of the inner core is 25°~35°.

[0011] Preferably, the included angle β between the second reducing tube and the central axis of the inner core 4 is 8°~16°.

[0012] Preferably, the inner wall of the straight elastic conduit is coated with a wear-resistant coating, which is a diamond-plated film or a high-temperature wear-resistant metal-ceramic coating.

[0013] Preferably, the coefficient of thermal expansion of the material used to make the inner core is less than that of the material used to make the outer mold.

[0014] Preferably, the inner diameter of the end of the outer mold body transitions into the straight elastic conduit.

[0015] Preferably, the length of the straight elastic conduit is 5~7mm; the width between two adjacent elastic arc plates is set according to the wire diameter of the multi-core conductor, ranging from 0.2~0.6mm.

[0016] An extrusion apparatus including the aforementioned variable aperture extrusion mold for multi-core conductors includes: a die cap, a die sleeve seat, an outer die head body, a core die seat, and a rotating tube. The die cap is disposed at the front end of the outer die head body through the die sleeve seat. An extrusion flow channel is provided between the outer die head body and the core die seat. The outer die body is placed on the core die seat. The inner core body is threadedly connected to the outer die body. The rotating tube is connected to the rear end of the inner core body. During the production process, the outer mold body is fixed on the mold core seat by the reaction force of the extruded material in the extrusion channel; when the multi-core conductor connector passes through, the rotating tube is rotated to drive the inner core body out; after the multi-core conductor connector passes through, the reverse rotating tube drives the inner core body to reset.

[0017] Compared with the prior art, the present invention has the following beneficial effects: This invention discloses a variable-aperture extrusion mold for multi-core conductors. A straight elastic conductor tube is cut to form multiple age-hardened, outward-opening elastic arc plates, which are dynamically constrained through internal and external thread engagement. During normal operation, these plates are locked and closed by the inner wall of the outer mold for precise sizing. When a connector of the multi-core conductor passes through, simply driving the inner core backward allows the elastic arc plates to disengage from the front end constraint of the outer mold, automatically opening and thus enlarging the aperture. After the connector passes, driving the inner core forward resets it. This invention achieves online, non-stop diameter changing by reciprocating the movement of the inner core. Overall, it enables rapid, non-destructive connector passage during continuous production, stable extruded layer quality, convenient operation, and high high-temperature reliability, resulting in comprehensive benefits that improve production line efficiency. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the structure of an extrusion mold with variable aperture for multi-core conductors according to the present invention; Figure 2 This is a schematic diagram of the inner core in a variable aperture extrusion mold for a multi-core conductor according to the present invention. Figure 3 This is a cross-sectional view of an extrusion apparatus according to the present invention, which includes an extrusion die with a variable aperture for a multi-core conductor.

[0019] In the figure, 1. Outer mold body; 2. Straight elastic conduit; 3. Wear-resistant coating; 4. Inner core body; 5. First reducing pipe; 6. Second reducing pipe; 7. Pressing mold cover; 8. Mold sleeve seat; 9. Machine head outer body; 10. Extrusion runner; 11. Mold core seat; 12. Rotating tube. Detailed Implementation

[0020] The following specific embodiments illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification.

[0021] Exemplary embodiments of the present invention will now be described with reference to the accompanying drawings. However, the present invention may be embodied in many different forms and is not limited to the embodiments described herein. These embodiments are provided to fully and completely disclose the invention and to fully convey its scope to those skilled in the art. The terminology used in the exemplary embodiments illustrated in the drawings is not intended to limit the invention. In the drawings, the same units / elements are referred to by the same reference numerals.

[0022] Unless otherwise stated, the terms used herein (including technical terms) have their common meaning as understood by one of ordinary skill in the art. Furthermore, it is understood that terms defined in commonly used dictionaries should be understood to have a meaning consistent with the context of their relevant field, and not to be interpreted as having an idealized or overly formal meaning.

[0023] The present invention will be further described in detail below with reference to specific embodiments. These descriptions are for explanation purposes only and are not intended to limit the scope of the invention.

[0024] This invention discloses a variable aperture extrusion die for multi-core conductors, with reference to... Figure 1 and Figure 2 The system comprises an outer mold body 1, with a tapered front end and a variable-diameter rear end, taking the conductor's forward direction as the front. An inner core body 4 is internally threaded onto the outer mold body 1. A first variable-diameter tube 5, a second variable-diameter tube 6, and a straight elastic conductor tube 2 are sequentially connected to the front end of the inner core body 4. The outer diameters of both the first and second variable-diameter tubes 5 and 6 gradually decrease, while the inner diameter of the first variable-diameter tube 5 gradually decreases, and the inner diameter of the second variable-diameter tube 6 remains constant. The inner diameter of the second variable-diameter tube 6 is the same as the inner diameter of the straight elastic conductor tube 2. The outer diameter of the straight elastic conductor tube 2 is equal to the minimum outer diameter of the second variable-diameter tube 6. The straight elastic conductor tube 2 is cut to form multiple spaced elastic arc plates, which are then age-hardened to form a certain outward angle. The inner wall of the outer mold body 1 is threadedly connected to the outer wall of the straight elastic conductor tube 2. During normal operation, the straight elastic conductor tube 2 is connected to the inner wall of the outer mold body 1. When the multi-core conductor is joined, the straight elastic conductor tube 2 separates from the inner wall of the outer mold body 1.

[0025] This invention discloses a variable-aperture extrusion die for a multi-core conductor. An inner core 4 is screwed into an outer die 1. A straight, elastic conductor tube 2 is threaded and locked to the inner wall of the outer die 1. An elastic arc-shaped sheet is constrained by the inner wall of the outer die 1 and retracts, forming a sizing zone matching the outer diameter of the multi-core conductor. Driving the inner core 4 backward causes the straight, elastic conductor tube 2 to disengage from the constraint of the inner wall of the outer die 1. The elastic arc-shaped sheet expands outward due to the pre-stress formed by age hardening, instantly enlarging the aperture and allowing unobstructed passage of the multi-core conductor's splice joint (the diameter of the splice joint is larger than that of the normal conductor). After the splice joint passes, the inner core 4 is pushed back to its original position, and the elastic arc-shaped sheet is compressed and retracted by the inner wall of the outer die 1, returning to the normal extrusion working state.

[0026] The inner diameters of the first reducing tube 5 and the second reducing tube 6 are limited, i.e. the inner diameter of the first reducing tube 5 gradually decreases while the inner diameter of the second reducing tube 6 remains constant. This allows the plastic to be compressed and plasticized in the first reducing tube 5 and then enter the sizing forming zone in the second reducing tube 6 and the straight elastic bearing tube 2, thereby ensuring the consistency of the wall thickness and the roundness accuracy of the extruded layer.

[0027] In one embodiment, the length of the straight elastic conduit 2 is 5~7mm, and the width between two adjacent elastic arc plates is set according to the wire diameter of the multi-core conductor, ranging from 0.2~0.6mm.

[0028] In one embodiment, a transition section is provided at the internal connection between the first reducing pipe 5 and the second reducing pipe 6, and a rounding is provided on the transition section to reinforce the connection between the first reducing pipe 5 and the second reducing pipe 6.

[0029] In one embodiment, the included angle α between the first variable diameter tube 5 and the central axis of the inner core 4 is 25°~35°, and the included angle β between the second variable diameter tube 6 and the central axis of the inner core 4 is 8°~16°. By setting the first variable diameter tube 5 and the second variable diameter tube 6 with specific cone angles connected in sequence at the front end of the inner core 4, a two-stage smooth compression flow channel is formed, thereby ensuring the extrusion quality.

[0030] In one embodiment, the inner wall of the straight elastic conduit is coated with a wear-resistant coating 3. The wear-resistant coating 3 is made of diamond film or high-temperature wear-resistant metal ceramic coating to improve wear resistance and extend mold life.

[0031] In one embodiment, the coefficient of thermal expansion of the material used to make the inner core 4 is less than that of the material used to make the outer mold 1. This is because the radial gap between the elastic arc sheet and the inner wall of the outer mold 1 will increase slightly as the temperature rises. In order to prevent jamming at high temperature, the expansion of the inner core 4 is less than that of the outer mold 1, which can ensure smooth forward and backward movements under hot conditions.

[0032] In one embodiment, the inner diameter of the end of the outer mold body 1 is transitionally fitted with the straight elastic bearing tube 2, which can ensure that the radial gap after the elastic arc sheet is compressed under normal working conditions is minimized, preventing plastic backflow or leakage, and can also ensure accurate guidance during reset, reducing the probability of eccentricity.

[0033] The present invention also discloses an extrusion apparatus including the aforementioned variable aperture extrusion die for multi-core conductors, with reference to... Figure 3 It includes: a compression mold cover 7, a mold sleeve seat 8, a machine head outer body 9, a mold core seat 11, and a rotating tube 12. The compression mold cover 7 is set at the front end of the machine head outer body 9 through the mold sleeve seat 8. An extrusion flow channel 10 is left between the machine head outer body 9 and the mold core seat 11. The outer mold body 1 is placed on the mold core seat 11. The inner core body 4 is threadedly connected to the outer mold body 1. The rotating tube 12 is connected to the rear end of the inner core body 4. During production, the outer mold 1 is fixed to the core seat 11 by the reaction force of the extruded material in the extrusion channel 10. When the conductor splice passes through, the rotating tube 12 drives the inner core 4 out of the outer mold 1. After the conductor splice passes through, the reverse rotating tube 12 drives the inner core 4 back into the outer mold 1. This extrusion device can achieve online aperture switching without stopping the machine or disassembling the mold. There is no need to stop the machine to change the mold during production, and the splice passage time is only a few seconds, which can improve continuous production efficiency and reduce scrap rate. It is particularly suitable for continuous extrusion production lines for long-distance, long-length cables.

[0034] Taking a multi-core conductor as an example, the outer mold body 1 is made of alloy steel, and its external dimensions match the internal fixed structure of the machine head. The diameter of the inner hole at the end of the outer mold body 1 is transitionally fitted with the end of the straight elastic bearing tube 2, thereby ensuring that the end of the straight elastic bearing tube 2 is always in a tight fit during normal production. The inner wall of the inner hole of the outer mold body 1 and the external thread of the straight elastic bearing tube 2 are threadedly fitted.

[0035] The inner core 4 is the fixed base of the straight elastic bearing tube 2. It is made of cobalt-based material because the expansion coefficient of cobalt-based material is less than that of alloy steel, making it suitable for extrusion in high-temperature die heads and preventing die jamming.

[0036] The angle between the first reducing pipe 5 and the axis is 30°, and the angle between the second reducing pipe 6 and the axis is 8°.

[0037] The straight elastic conduit 2 is made of cobalt-based and chromium-tungsten carbide elastic tubing. The end tube is evenly cut into multiple elastic arc pieces along the axis, and the elastic arc pieces are formed by age hardening and set with an outward opening angle of 0.5°. When the outer mold body 1 is tightly closed, the elastic arc pieces reform a slightly smaller circular hole. The straight elastic conduit 2 is coated with a diamond film or a high-temperature wear-resistant metal ceramic coating to improve the wear resistance inside the tube.

[0038] During the normal production process of multi-core conductor insulated wire, the straight elastic bearing tube 2 is entirely within the end hole of the outer mold body 1, the end of the straight elastic bearing tube 2 is in a tightly closed state, and the diameter of the straight elastic bearing tube 2 is just suitable for passing through the multi-core conductor with a normal structure. The multi-core conductor enters sequentially. Figure 3 The rotating tube 12 and the straight elastic bearing tube 2 are then fed into the die head for insulating extrusion.

[0039] During the multi-core conductor splicing process, the rotating tube 12 outside the machine head drives the tail end structure of the straight elastic bearing tube 2 to rotate counterclockwise, pushing the end tube of the straight elastic bearing tube 2 out of the end hole of the outer mold body 1 and into the convergence area of ​​the outer mold body 1. At this time, the straight elastic bearing tube 2 is no longer constrained by the internal port of the outer mold body 1, and each elastic arc plate is in an outward expansion state, increasing the cross-sectional area through which the conductor passes. When the thicker conductor splice passes through the machine head, the rotating tube 12 is used to rotate and push the straight elastic bearing tube 2 back into the internal port of the outer mold body 1. The elastic arc plates tighten the mold core hole diameter again, ensuring that the multi-core conductor is re-aligned after passing through the mold. This solves the problem of conductors being too large to pass smoothly through the mold when splicing the beginning and end of multi-core conductor discs, and has a significant effect on improving the continuous production efficiency and material utilization of multi-core conductor cables.

[0040] In summary, the present invention provides a variable aperture extrusion die for multi-core conductors, which uses the elastic arc sheet of the straight elastic conductor tube 2 to freely expand the aperture. This solves the problem that the conductor is too large to pass smoothly through the die due to the connection between the beginning and end of different coils of multi-core conductors. It has a significant effect on improving the continuous production efficiency and material utilization of multi-core conductor cables.

[0041] The above description is merely a preferred embodiment of the present invention and is not intended to limit the technical solution of the present invention in any way. Those skilled in the art should understand that, without departing from the spirit and principles of the present invention, the technical solution can be modified and replaced in several simple ways, and these modifications and replacements are all within the scope of protection covered by the claims.

Claims

1. A variable aperture extrusion mold for multi-core conductors, characterized in that, With the conductor's forward direction as the front, it includes an outer mold body (1), the front end of which is conical and the rear end is set with a variable diameter; the outer mold body (1) is internally threaded with an inner core body (4), and the front end of the inner core body (4) is provided with a first variable diameter tube (5), a second variable diameter tube (6) and a straight elastic bearing tube (2) connected in sequence. The outer diameters of the first variable diameter tube (5) and the second variable diameter tube (6) gradually decrease, the inner diameter of the first variable diameter tube (5) gradually decreases, and the inner diameter of the second variable diameter tube (6) is constant. The inner diameter of the second variable diameter tube (6) is the same as the inner diameter of the straight elastic bearing tube (2); the outer diameter of the straight elastic bearing tube (2) is equal to the smallest outer diameter of the second variable diameter tube (6); the straight elastic bearing tube (2) is cut to form multiple spaced elastic arc pieces, and the elastic arc pieces are formed by age hardening to form a certain outward opening angle; the inner wall of the outer mold body (1) is threadedly connected to the outer wall of the straight elastic bearing tube (2). During normal operation, the straight elastic conduit (2) is connected to the inner wall of the outer mold body (1); when the multi-core conductor is joined, the straight elastic conduit (2) is separated from the inner wall of the outer mold body (1).

2. The variable aperture extrusion die for multi-core conductors according to claim 1, characterized in that, A transition section is provided at the internal connection between the first reducer (5) and the second reducer (6).

3. The variable aperture extrusion die for multi-core conductors according to claim 2, characterized in that, The transition section is rounded.

4. The variable aperture extrusion die for multi-core conductors according to claim 1, characterized in that, The angle α between the central axis of the first reducing tube (5) and the inner core (4) is 25°~35°.

5. The variable aperture extrusion die for multi-core conductors according to claim 1, characterized in that, The included angle β between the second reducing tube (6) and the central axis of the inner core (4) is 8°~16°.

6. The variable aperture extrusion die for multi-core conductors according to claim 1, characterized in that, The inner wall of the straight elastic conduit (2) is coated with a wear-resistant coating (3), which is made of diamond film or high-temperature wear-resistant metal ceramic coating.

7. The variable aperture extrusion die for multi-core conductors according to claim 1, characterized in that, The coefficient of thermal expansion of the material used to make the inner core (4) is less than that of the material used to make the outer mold (1).

8. The variable aperture extrusion die for multi-core conductors according to claim 1, characterized in that, The inner diameter of the end of the outer mold body (1) is fitted with the straight elastic conduit (2).

9. The variable aperture extrusion die for multi-core conductors according to claim 1, characterized in that, The length of the straight elastic conduit (2) is 5~7mm; the width between two adjacent elastic arc plates is set according to the wire diameter of the multi-core conductor, and the range is 0.2~0.6mm.

10. An extrusion apparatus comprising an extrusion die with a variable aperture for a multi-core conductor as described in any one of claims 1 to 9, characterized in that, include: The die cover (7), die sleeve seat (8), die head body (9), die core seat (11) and rotating tube (12) are provided. The die cover (7) is set at the front end of the die head body (9) through the die sleeve seat (8). An extrusion flow channel (10) is left between the die head body (9) and the die core seat (11). The outer die body (1) is placed on the die core seat (11). The inner core body (4) is threadedly connected to the outer die body (1). The rotating tube (12) is connected to the rear end of the inner core body (4). During the production process, the outer mold body (1) is fixed on the core seat (11) by the reaction force of the extruded material in the extrusion channel (10); when the multi-core conductor connector passes through, the rotating tube (12) is rotated to drive the inner core body (4) out; after the multi-core conductor connector passes through, the rotating tube (12) is rotated in the opposite direction to drive the inner core body (4) back to its original position.

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