Injection molding method and injection molding device for prefabricated cable

Abstract

The invention relates to an injection molding method for a prefabricated cable, and the method comprises the steps: respectively stripping the outer skins of a main cable and a branch cable, exposing a main cable conductor and a branch cable conductor, and carrying out the crimping connection through a C-shaped connecting piece; the outer side of the C-shaped connecting piece and the outer side of the independent section of the main cable conductor are wrapped with an insulating layer; an isolation cover is installed on the outer side of the parallel section of the main cable conductor, the isolation cover wraps the parallel section of the main cable conductor and the outer side of the branch cable conductor, and a positioning pin made of an insulating material is installed on the outer side face of the isolation cover; and the joint of the main cable and the branch cable is placed in an injection mold for injection molding, and the positioning pin abuts against the inner wall of the injection mold. The connecting part of the cable after injection molding is centered through the isolation cover with the positioning pin, so that the pressure resistance and the structural strength of the branch connector are ensured; meanwhile, the radial tensile performance of the branch connector is improved, and the waterproof performance of the prefabricated cable is prevented from being affected by cracking of the branch connector.

Description

Technical Field

[0001] The invention relates to the technical field of cable preparation, and in particular to an injection molding method and an injection molding device for a prefabricated cable. Background Art

[0002] Prefabricated cables are branch cables prefabricated at specific locations of the trunk cables according to the power distribution design requirements. They have good power supply reliability and are widely used in medium and high-rise buildings, electrical shafts, etc. After the prefabricated cables are crimped between the trunk cables and the branch cables, a branch connector needs to be injection molded at the connection to improve the air tightness and waterproofness of the connection.

[0003] When the branch connector of the prefabricated cable is injection molded with halogen-free low-smoke rubber, the cable is easily pushed to one side due to the high injection pressure, affecting the pressure resistance and structural strength of the branch connector; and the existing prefabricated cables mainly improve the axial tensile resistance of the branch cable by setting a reinforcement ring on the branch cable, and during laying, the radial tension on the branch connector may cause damage to the branch connector, affecting the insulation and waterproof performance of the prefabricated cable.

[0004] Based on the above technical problems, the present application proposes an injection molding method and an injection molding device for prefabricated cables. Summary of the invention

[0005] The object of the present invention is to provide an injection molding method and an injection molding device for a prefabricated cable to solve the technical problems mentioned in the background technology. The object of the present invention is achieved through the following technical solutions: A method for injection molding a prefabricated cable comprises the following steps: Step S1, peeling off the outer skin of the trunk cable and the outer skin of the branch cable respectively to expose the trunk cable conductor and the branch cable conductor, and using a C-type connector to crimp the branch cable conductor to the trunk cable conductor; Step S2, wrapping an insulating layer around the outside of the C-type connector and the outside of the independent section of the main cable conductor, wherein the independent section refers to the part of the main cable conductor located on the side of the C-type connector away from the branch cable; Step S3, installing an isolation cover on the outside of the parallel section of the main cable conductor, the isolation cover covers the parallel section of the main cable conductor and the outside of the branch cable conductor, and the outer side of the isolation cover is installed with a positioning pin of an insulating material, wherein the parallel section refers to the part of the main cable conductor located on the side of the C-type connector close to the branch cable; Step S4, placing the connection between the trunk cable and the branch cable into an injection mold for injection molding, with the positioning pin abutting against the inner wall of the injection mold, and forming a branch connector after cooling and shaping.

[0006] Furthermore, a hollow hole is provided on the isolation cover.

[0007] Furthermore, the isolation cover comprises two symmetrical and equal-sized clamping members, and a clamping portion is provided between the two clamping members.

[0008] Furthermore, the clamping member includes a branch clamping portion, a connecting plate and a trunk clamping portion, the branch clamping portion and the trunk clamping portion are both semi-tubular, the connecting plate is installed between the branch clamping portion and the trunk clamping portion; the positioning pin is installed on the connecting plate.

[0009] Furthermore, the insulating layer is a heat shrinkable insulating tape.

[0010] Furthermore, the end of the positioning pin is provided with a chamfer or a step.

[0011] An injection molding device for the injection molding method of any of the above-mentioned prefabricated cables comprises two symmetrical half molds, the connecting surfaces of the two half molds are provided with a mold groove, the sides of the mold groove are provided with a threading groove and an injection molding groove, when the two half molds are closed, the two mold grooves surround a molding cavity, the two threading grooves surround a threading hole, the two injection molding grooves are spliced ​​into an injection molding flow channel, the bottom of the mold groove is provided with a positioning hole, and the end of the positioning pin is inserted into the positioning hole.

[0012] Furthermore, the injection groove is connected to the middle of the mold groove; an injection branch groove is opened on the injection groove, and when the two half molds are closed, the two injection branch grooves are combined into an injection branch channel, and the injection branch channel is connected to the largest cross-section of the cavity.

[0013] Furthermore, the aperture ratio of the injection molding runner to the injection molding branch runner is 1:0.75-0.85.

[0014] The technical solution provided in the embodiments of the present application has at least the following technical effects or advantages: 1. By installing an isolation cover with positioning pins on the outside of the main cable conductor and the branch cable conductor, it can be ensured that the cable connection is in the middle of the branch connector after injection molding, ensuring the pressure resistance and structural strength of the branch connector; at the same time, the isolation cover can improve the radial tensile strength of the branch connector, avoiding cracking of the branch connector to affect the waterproof performance of the prefabricated cable; 2. By opening a hollow hole on the isolation cover and not covering the outer side of the parallel section of the main cable conductor and the branch cable conductor with an insulating layer, the injection plastic can pass through the isolation cover and wrap around the outer side of the conductor, thereby increasing the friction between the conductor and the injection plastic and improving the axial tensile resistance of the branch connector; 3. By using heat shrinkable insulation tape as the insulation layer, the insulation layer can shrink during injection molding, expelling air and moisture between the insulation layer and the conductor, thus ensuring the insulation performance of the prefabricated cable; 4. By installing the positioning pins at the connecting plate between the branch clamping part and the trunk clamping part, the positioning pins are staggered with the trunk cable conductor and the branch cable conductor to prevent water vapor from entering the branch connector along the positioning pins and affecting the insulation performance of the prefabricated cable. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The drawings in the specification, which constitute a part of this application, are used to provide a further understanding of the present invention. The illustrative embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0016] Figure 1 This is a schematic diagram of the half-mold structure of an embodiment of the present application; Figure 2 This is a schematic diagram of the installation of the isolation cover in the embodiment of the present application; Figure 3 This is a schematic diagram of a clamping structure according to an embodiment of the present application; Figure 4 This is another schematic diagram of the structure of a clamping member according to an embodiment of the present application; Figure 5 This is a schematic diagram of the installation of the cable connector and the half-mold in the embodiment of the present application; Figure 6 for Figure 5 A partial enlarged view of .

[0017] Markings in the attached drawing: 1. Main cable; 11. Main cable conductor; 2. Branch cable; 21. Branch cable conductor; 3. C-type connector; 4. Isolation cover; 41. Branch clamping part; 42. Connecting plate; 43. Main clamping part; 44. Snap-in hole; 45. Snap-in pin; 46. Hollow hole; 5. Positioning pin; 6. Half mold; 61. Mould groove; 62. Threading groove; 63. Injection molding groove; 64. Injection molding branch groove; 65. Positioning hole. DETAILED DESCRIPTION

[0018] In order to better understand the above technical solution, the above technical solution will be described in detail below in conjunction with the drawings and specific implementation methods of the specification. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is by no means intended to limit the present invention and its application or use. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0019] Example 1 like Figure 1As shown, an injection molding device includes two symmetrical half molds 6, and the connecting surfaces of the two half molds 6 are provided with symmetrical grooves 61, and the groove 61 is a groove body with a larger left side and a smaller right side. The left side of the groove 61 is provided with two threading grooves 62 for inserting the trunk cable and the branch cable, and the right side of the groove 61 is provided with a threading groove 62 for inserting the trunk cable. The upper side of the groove 61 is provided with an injection molding groove 63, and the middle of the injection molding groove 63 is provided with an injection molding branch groove 64 connected to the groove 61, and the bottom of the groove 61 is also provided with a positioning hole 65.

[0020] When the two half molds 6 are closed, the two mold grooves 61 form a mold cavity for molding the branch connector; the threading groove 62 forms a threading hole to clamp and fix the main cable and the branch cable; the injection molding groove 63 is spliced ​​into an injection molding flow channel, and the injection molding branch groove 64 is spliced ​​into an injection molding branch flow channel to inject molten injection plastic into the mold cavity. Among them, the injection molding flow channel is connected to the middle of the mold cavity, and the injection molding branch flow channel is connected to the largest part of the mold cavity cross section. The aperture ratio of the injection molding flow channel to the injection molding branch flow channel is 1:0.8, so as to ensure that the injection molding plastic can quickly fill the mold cavity and reduce the pressure of the injection molding plastic on the cable connection to avoid cable deviation.

[0021] Example 2 like Figure 2-6 As shown, a method for injection molding a prefabricated cable comprises the following steps: Step S1 , peel off the outer sheaths of the trunk cable 1 and the branch cable 2 respectively to expose the trunk cable conductor 11 and the branch cable conductor 21 , and use a C-type connector 3 to crimp the branch cable conductor 21 onto the trunk cable conductor 11 .

[0022] Among them, the C-type connector is crimped by a symmetrical crimping pliers. After crimping, a convex ring surrounding the circumference of the C-type connector is formed on the surface of the C-type connector, thereby increasing the contact area between the injection molding material and the C-type connector and improving the tensile performance between the injection molding material and the C-type connector.

[0023] Step S2: wrap an insulating layer (not shown) around the outside of the C-type connector 3 and the outside of the independent section of the main cable conductor 11. The independent section refers to the part of the main cable conductor 11 located on the side of the C-type connector 3 away from the branch cable 2, that is, Figure 2 The right part of the C-shaped connector 3.

[0024] The insulating layer is a heat-shrinkable insulating tape. During injection molding, the heat-shrinkable insulating tape shrinks due to heat, and can squeeze out the air and moisture between the insulating layer and the C-type connector 3 and the main cable conductor 11, thereby ensuring the insulation performance of the prefabricated cable.

[0025] Step S3, install the isolation cover 4 outside the parallel section of the main cable conductor 11, the isolation cover 4 covers the parallel section of the main cable conductor 11 and the outside of the branch cable conductor 21, and the outer side of the isolation cover 4 is installed with a positioning pin 5 of insulating material. Among them, the parallel section refers to the part of the main cable conductor 11 located on the side of the C-type connector 3 close to the branch cable 2, that is, Figure 2 The left part of the C-shaped connector 3.

[0026] like Figure 2-Figure 4 As shown, the isolation cover 4 includes two symmetrical and equal-sized clamping parts, and a clamping part is arranged between the two clamping parts. Specifically, the clamping part includes a branch clamping part 41, a connecting plate 42 and a trunk clamping part 43. The branch clamping part 41 is a half-tube structure matched with the branch cable conductor 21, and the trunk clamping part 43 is a half-tube structure matched with the trunk cable conductor 11. The connecting plate 42 is a triangular plate. The connecting plate 42 is installed between the branch clamping part 41 and the trunk clamping part 43, and the positioning pin 5 is fixedly installed on the connecting plate 42. By installing the positioning pin at the connecting plate between the branch clamping part and the trunk clamping part, the positioning pin is staggered with the trunk cable conductor and the branch cable conductor, so as to prevent water vapor from entering the branch connector along the positioning pin and affecting the insulation performance of the prefabricated cable.

[0027] The branch clamping part 41 and the trunk clamping part 43 of one of the clamping parts are evenly distributed with snap-in holes 44 on both sides, and the branch clamping part 41 and the trunk clamping part 43 of the other clamping part are evenly distributed with snap-in pins 45 on both sides. The two clamping parts are snapped together through the snap-in holes 44 and the snap-in pins 45, so that the two branch clamping parts 41 clamp and fix the branch cable conductor 21, and the two trunk clamping parts 43 clamp and fix the trunk cable conductor 11.

[0028] Preferably, the branch clamping portion 41, the connecting plate 42 and the trunk clamping portion 43 are all provided with hollow holes 46, so that the injection plastic can pass through the hollow holes 46 and directly connect with the trunk cable conductor 11 and the branch cable conductor 21. Since the trunk cable conductor 11 and the branch cable conductor 21 are both twisted by guide wires, the friction between the injection plastic and the trunk cable conductor 11 and the branch cable conductor 21 can be increased, thereby improving the axial tensile resistance of the prefabricated cable.

[0029] The branch clamping part 41, the connecting plate 42, the trunk clamping part 43 and the positioning pin 5 are all made of nylon, and the branch clamping part 41, the connecting plate 42, the trunk clamping part 43 and the positioning pin 5 are made by injection molding. The end of the positioning pin 5 is provided with a chamfer or a step, so as to enhance the coating effect of the injection plastic on the end of the positioning pin 5, and prevent water vapor from entering the interior of the prefabricated cable along the positioning pin 5.

[0030] Step S4: Figure 5 , Figure 6As shown, the connection between the trunk cable 1 and the branch cable 2 is placed in one half mold 6 of the injection mold, so that the trunk cable 1 and the branch cable 2 are respectively clamped in the threading grooves 62 at both ends of the groove 61, and the end of the positioning pin 5 is inserted in the positioning hole 65. The other half mold 6 is driven to close the mold by the mold closing mechanism, so that another positioning pin 5 is inserted in the positioning hole 65 of the other half mold 6, so that the position of the isolation cover 4 in the groove 61 is fixed. The molten injection plastic is injected into the cavity through the injection runner, and the branch connector is formed after cooling and finalization.

[0031] By installing an isolation cover with positioning pins on the outside of the main cable conductor and the branch cable conductor, it can be ensured that the cable connection is in the middle of the branch connector after injection molding, thereby ensuring the pressure resistance and structural strength of the branch connector; at the same time, the isolation cover can improve the radial tensile resistance of the branch connector, avoiding cracking of the branch connector and affecting the waterproof performance of the prefabricated cable.

[0032] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0033] In the description of the present invention, it is necessary to understand that the directions or positional relationships indicated by directional words such as "front, back, up, down, left, right", "lateral, vertical, perpendicular, horizontal" and "top, bottom" are usually based on the directions or positional relationships shown in the drawings. They are only for the convenience of describing the present invention and simplifying the description. Unless otherwise specified, these directional words do not indicate or imply that the device or element referred to must have a specific direction or be constructed and operated in a specific direction. Therefore, they cannot be understood as limiting the scope of protection of the present invention: the directional words "inside and outside" refer to the inside and outside relative to the contours of each component itself.

[0034] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for injection molding a prefabricated cable, characterized in that: The following steps are involved: Step S1, peeling off the outer skin of the trunk cable and the outer skin of the branch cable respectively to expose the trunk cable conductor and the branch cable conductor, and using a C-type connector to crimp the branch cable conductor to the trunk cable conductor; Step S2, wrapping an insulating layer around the outside of the C-shaped connector and the outside of the independent section of the main cable conductor, wherein the independent section refers to the portion of the main cable conductor located on the side of the C-shaped connector away from the branch cable; Step S3, installing an isolation cover on the outside of the parallel section of the main cable conductor, the isolation cover covers the parallel section of the main cable conductor and the outside of the branch cable conductor, and the outer side of the isolation cover is installed with a positioning pin of an insulating material, wherein the parallel section refers to the part of the main cable conductor located on the side of the C-type connector close to the branch cable; Step S4: placing the connection between the trunk cable and the branch cable into an injection mold for injection molding, wherein the positioning pin abuts against the inner wall of the injection mold, and a branch connector is formed after cooling and shaping.

2. The injection molding method of a prefabricated cable according to claim 1, characterized in that: The isolation cover is provided with a hollow hole.

3. The injection molding method of a prefabricated cable according to claim 1, characterized in that: The isolation cover comprises two symmetrical and equal-sized clamping members, and a clamping portion is arranged between the two clamping members.

4. The injection molding method of a prefabricated cable according to claim 3, characterized in that: The clamping member includes a branch clamping portion, a connecting plate and a trunk clamping portion. The branch clamping portion and the trunk clamping portion are both semi-tubular. The connecting plate is installed between the branch clamping portion and the trunk clamping portion. The positioning pin is installed on the connecting plate.

5. The injection molding method of a prefabricated cable according to claim 1, characterized in that: The insulating layer is a heat shrinkable insulating tape.

6. The injection molding method of a prefabricated cable according to claim 1, characterized in that: The end of the positioning pin is provided with a chamfer or a step.

7. An injection molding device for the injection molding method of the prefabricated cable according to any one of claims 1 to 6, comprising two symmetrical half molds, the connecting surfaces of the two half molds are provided with a groove, the side of the groove is provided with a threading groove and an injection molding groove, when the two half molds are closed, the two grooves surround the molding cavity, the two threading grooves surround the threading hole, and the two injection molding grooves are spliced ​​into an injection molding flow channel, characterized in that: A positioning hole is formed at the bottom of the groove, and the end of the positioning pin is inserted into and removed from the positioning hole.

8. An injection molding device according to claim 7, characterized in that: The injection molding groove is connected with the middle part of the molding groove; the injection molding groove is provided with an injection molding branch groove, when the two half molds are closed, the two injection molding branch grooves are combined into an injection molding branch channel, and the injection molding branch channel is connected with the largest cross-section of the molding cavity.

9. An injection molding device according to claim 8, characterized in that: The aperture ratio of the injection molding flow channel to the injection molding branch flow channel is 1:0.75-0.85.

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