A miniature high-strength stainless steel laser-welded fiber optic cable splitter and assembly method

Abstract

This invention discloses a miniature high-strength stainless steel laser-welded optical cable splitter and its assembly method, relating to the field of optical communication device technology. The splitter includes: a branch tube for accommodating multiple branch optical cables; a fixing tube for positioning the main optical cable; a glue-injection tube, a hollow sleeve whose inner cavity accommodates the branch tube and fixing tube, forming an optical cable junction cavity, with glue-injection holes on its side wall; and an outer sheath, fitted over the internal core assembly and sealed by annular laser welding. During assembly, the branch optical cables are bundled and passed through the branch tube and pre-fixed with hot melt adhesive tape. The main optical cable passes through the fixing tube and the glue-injection tube. After the optical fibers are connected, the three components are inserted and combined. Adhesive is injected through the glue-injection holes and cured to form the internal core. Finally, the outer sheath is inserted for laser welding. The overall dimensions of the splitter of this invention are ≤48mm × Φ With a diameter of 8mm, it employs a dual guarantee of axial positioning injection and laser welding encapsulation to achieve high strength and excellent sealing performance under extreme miniaturization, making it suitable for mass production.

Description

Technical Field

[0001] This invention relates to the field of optical communication device technology, and in particular to a miniature high-strength stainless steel laser-welded optical cable splitter and its assembly method. Background Technology

[0002] As optical communication systems evolve towards higher density and miniaturization, the internal wiring space of optoelectronic equipment becomes increasingly limited, placing higher demands on optical cable branch protection devices. Traditional optical cable branch protection solutions mainly employ branch boxes or branch enclosures, using large cavities to house fiber optic splices and provide mechanical protection. However, these branch boxes are bulky, typically exceeding 100mm in length and 20mm in outer diameter, making it difficult to meet the miniaturization requirements of modern high-density equipment internal wiring.

[0003] To address the size issue, a simple solution using heat-shrink tubing for branch protection has emerged in existing technologies. This solution involves bundling multiple branch optical cables with the main optical cable, wrapping them in heat-shrink tubing, and then heating and shrinking them to achieve initial fixation and protection. However, heat-shrink tubing is made of a high-molecular polymer, which has limited mechanical strength and insufficient tensile and torsional resistance. When subjected to external pulling or twisting forces, it is prone to causing internal fiber breakage, making it difficult to pass rigorous reliability tests. Furthermore, heat-shrink tubing cannot provide an airtight seal, resulting in poor protection in humid or corrosive environments.

[0004] In specific applications requiring high-strength connections between a main optical cable and multiple branch optical cables within an ultra-miniaturized node—for example, within an installation space with a total length of less than 48mm and a maximum outer diameter of less than 8mm—it is necessary to simultaneously accommodate 12 branch optical cables while meeting reliability requirements such as tensile strength, torsional strength, and sealing. Traditional branch boxes are unsuitable due to their excessive size, while simple solutions such as heat-shrink tubing cannot meet the strength requirements. Furthermore, metal armoring or injection molding solutions are difficult to mass-produce within such a small size due to their complex structure, high processing difficulty, and high cost.

[0005] Therefore, there is an urgent need to develop an optical cable branch protection device that combines extreme miniaturization, high mechanical strength, excellent sealing performance, and good manufacturability to meet the pressing needs of internal wiring in high-density optoelectronic equipment. Summary of the Invention

[0006] In order to overcome the above-mentioned defects of the prior art, the present invention provides a miniature high-strength stainless steel laser-welded optical cable splitter and assembly method to solve the problems existing in the background art.

[0007] This invention provides the following technical solution: a miniature high-strength stainless steel laser-welded optical cable splitter and its assembly method, wherein the branch tube is used to accommodate and axially position multiple branch optical cables; Fixed tube, used for axial positioning of the main optical cable; The glue injection tube is a hollow sleeve, the inner cavity of which is used to accommodate the branch tube and the fixed tube, and the two are spaced apart along the axial direction to form an optical cable junction cavity; at least one glue injection hole is opened on the side wall of the glue injection tube. The main optical cable and the branch optical cable are optically connected in the optical cable junction cavity. The inner cavity of the glue injection tube is filled with adhesive injected and cured through the glue injection hole to solidify the fixing tube, the branch tube, the main optical cable and the branch optical cable into an internal core assembly. It also includes an outer protective tube, which is sleeved on the outside of the inner core assembly and forms a tight fit with the inner core assembly. The outer protective tube is fused and sealed with the inner core assembly by annular laser welding to form an integrated packaging structure.

[0008] Preferably, one end of the fixing tube is provided with a first insertion part, and one end of the glue injection tube is provided with an interface structure that mates with the first insertion part; The other end of the glue injection tube is provided with a second insertion part, which is used to insert and cooperate with one end of the branch tube.

[0009] Preferably, the branch tube is pre-fixed to the multiple branch optical cables by hot melt adhesive tape. The hot melt adhesive tape is wrapped around the outer periphery of the bundled branch optical cables and cured by high temperature, so that the branch tube and the bundled branch optical cables are fixed together as one unit.

[0010] Preferably, the injection hole is a U-shaped hole, a circular hole, or an elongated hole, used to inject adhesive into the optical cable junction cavity.

[0011] Preferably, the branch pipe, fixing pipe, glue injection pipe and outer protective pipe are all made of SUS304 stainless steel and undergo electrochemical polishing treatment.

[0012] Preferably, the overall dimensions of the brancher are: length ≤ 48mm, outer diameter ≤ 8mm.

[0013] Preferably, the central through-hole of the branch tube is used to accommodate multiple loosely bundled branch optical cables passing through, and the diameter of the central through-hole of the fixed tube is adapted to the outer diameter of the main optical cable.

[0014] An assembly method for a miniature high-strength stainless steel laser-welded optical cable splitter includes the following steps: S1: Optical Cable Preparation and Preliminary Positioning After multiple branch optical cables are bundled together, they are wrapped and fixed with hot melt adhesive tape and passed through the central through hole of the branch tube together; the hot melt adhesive tape is heated to melt and solidify, fixing the branch tube and the branch optical cable bundle into one unit; The main optical cable is passed through the fixing tube and the glue injection tube in sequence, and the fixing tube and the glue injection tube are inserted and fixed. S2: Internal Assembly and Gluing Connect the fiber optic sections of the main optical cable and the branch optical cable; Push the fixing tube and the glue injection tube towards the branch tube so that the glue injection tube is inserted and fixed to the branch tube; Adhesive is injected into the optical cable junction cavity through the injection hole on the injection tube; S3: Curing and External Packaging The adhesive is cured by heating to form the internal core assembly; Insert the internal core assembly into the outer protective tube; A 360° circumferential laser welding is performed at the tail end of the outer protective tube to fuse and seal the outer protective tube with the glue injection tube; S4: Inspection The finished product was tested for dimensions, appearance, pull-out force, torsional properties, and optical properties. Preferably, the adhesive is an epoxy resin adhesive.

[0015] Preferably, the laser welding is continuous or pulsed laser welding, and the welding depth is at least through the outer protective tube wall thickness and melts into the outer wall of the glue injection tube.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. This invention simplifies the overall structure of the splitter into four parts: branch tube, fixing tube, injection tube, and outer protective tube. By adopting an axially spaced layout, the overall size can be controlled within the limit range of length ≤48mm and maximum outer diameter ≤8mm. Within this miniaturized space, it can still accommodate 12 branch optical cables and 1 main optical cable for connection and protection. This fills the gap in the existing technology that cannot balance capacity and strength under extreme size, thus meeting the usage requirements of internal wiring in high-density optoelectronic equipment. 2. The internal core assembly of this invention consists of a branch tube, a fixed tube, and a glue injection sleeve. The parts have simple shapes and are easy to precision machine. At the same time, the parts are axially positioned by a plug-in structure. During assembly, they can be plugged in one by one to form an accurate optical cable junction cavity without the need for complicated tooling fixtures. With the hot melt adhesive tape pre-fixing process and glue injection window design, the entire assembly process is convenient and reliable, improving production efficiency and product consistency. 3. This invention injects epoxy resin adhesive into the optical cable junction cavity through the injection hole. After curing, the branch tube, fixing tube, main optical cable, and 12 branch optical cables are fixed together as one unit. The adhesive fully wets all optical cables, effectively dispersing external tension and avoiding stress concentration at the optical fiber splice point, thereby improving tensile and torsional resistance. After the outer sheath is tightly fitted with the internal core assembly, it is fused and sealed by 360° annular laser welding to form an all-metal integrated shell. This not only ensures the structural strength of the shell but also achieves permanent fixation. This dual protection greatly improves the tensile, compressive, and torsional strength of the brancher. Attached Figure Description

[0017] Figure 1 This is an exploded view of the present invention.

[0018] Figure 2 This is a schematic diagram of the assembly process of the present invention.

[0019] Figure 3 This is a schematic diagram showing the assembly of the present invention.

[0020] The attached diagram is labeled as follows: 100, main optical cable; 200, branch optical cable; 300, hot melt adhesive tape; 400, branch tube; 500, fixing tube; 501, first plug-in part; 600, glue injection tube; 601, second plug-in part; 602, glue injection hole; 700, outer protective tube. Detailed Implementation

[0021] The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, so that the advantages and features of the present invention can be more easily understood by those skilled in the art, thereby providing a clearer and more explicit definition of the scope of protection of the present invention.

[0022] This invention provides a miniature high-strength stainless steel laser-welded optical cable splitter, such as... Figure 1-3 As shown, it includes: main optical cable 100, branch optical cable 200, hot melt adhesive tape 300, branch tube 400, fixing tube 500, glue injection tube 600, and outer sheath 700. Branch tube 400 is used to accommodate and axially position multiple branch optical cables 200. Branch tube 400 is a ring-shaped part, the diameter of its central through hole is slightly larger than the outer diameter of the bundled 12 branch optical cables 200, to facilitate the passage of optical cables. Branch tube 400 and multiple branch optical cables 200 are pre-fixed by hot melt adhesive tape 300. Hot melt adhesive tape 300 is wrapped around the outer periphery of the bundled branch optical cables 200 and cured by high temperature, so that branch tube 400 and branch optical cables 200 are bundled and fixed as one unit.

[0023] The fixing tube 500 is used for axial positioning of the main optical cable 100. The fixing tube 500 is also a ring-shaped part with a central through hole diameter of Φ2.1mm, which forms a small gap fit with the outer diameter of the main optical cable 100 of 2.0mm. This facilitates cable threading and allows for tight fixation with adhesive after gluing, ensuring that the main optical cable is centered.

[0024] The glue injection tube 600 is a hollow sleeve whose inner cavity accommodates the branch tube 400 and the fixing tube 500, and the two are spaced apart axially to form an optical cable junction cavity. The inner diameter of the glue injection tube 600 is slightly larger than the outer diameter of the branch tube 400 and the fixing tube 500 to accommodate them and allow axial adjustment. At least one glue injection hole 602 is provided on the side wall of the glue injection tube 600. In this embodiment, it is preferably a U-shaped hole with the U-shaped opening facing the end or side of the glue injection tube 600, which facilitates the insertion of the glue injection gun tip and can also serve as a vent hole during glue injection to ensure that the glue is filled tightly and without air bubbles.

[0025] One end of the fixing tube 500 is provided with a first insertion part 501, and one end of the glue injection tube 600 is provided with an interface structure that mates with the first insertion part 501; the other end of the glue injection tube 600 is provided with a second insertion part 601, which is used to mate with one end of the branch tube 400. Both the first insertion part 501 and the second insertion part 601 are stepped structures, that is, the outer diameter changes in a stepped manner, and the ends of the glue injection tube 600 and the branch tube 400 that mate with them have corresponding stepped holes. This stepped insertion structure not only facilitates guidance and axial positioning during assembly, but also forms an effective sealing barrier during the glue injection process, preventing the adhesive from overflowing from the insertion gap and ensuring that the glue is used entirely to fill the optical cable junction cavity.

[0026] The main optical cable 100 and the branch optical cable 200 are connected within the optical cable junction cavity (either by fusion splicing or mechanical splicing). The inner cavity of the glue injection tube 600 is filled with adhesive injected and cured through the glue injection hole 602 to solidify the fixing tube 500, the branch tube 400, the main optical cable 100, and the branch optical cable 200 into an internal core assembly. The adhesive is preferably epoxy resin, which has advantages such as good fluidity, high bonding strength, and low curing shrinkage. After curing, it forms a solid whole, effectively dispersing external tensile force and preventing stress concentration at the optical fiber connection point.

[0027] It also includes an outer sheath 700, which is fitted over the inner core assembly and forms a tight fit with it. The outer sheath 700 is a thin-walled stainless steel sleeve, the inner diameter of which matches the outer diameter of the injection tube 600 (e.g., Φ7.8mm). After assembly, it is fused and sealed to the inner core assembly by annular laser welding to form an integrated encapsulation structure. The laser welding uses a continuous or pulsed laser, and the welding depth is at least through the wall thickness of the outer sheath 700 and melts into the outer wall of the injection tube 600, achieving a permanent metallurgical bond.

[0028] Branch tube 400, fixed tube 500, glue injection tube 600, and outer protective tube 700 are all made of SUS304 stainless steel and undergo electropolishing treatment. This material has good mechanical strength, corrosion resistance, and laser welding performance. Polishing further improves surface finish, reduces friction, and facilitates assembly.

[0029] The overall dimensions of the splitter are: length ≤ 48mm, maximum outer diameter ≤ 8mm, to fit within the limited internal installation space of high-density optoelectronic equipment. Within this miniature size, the inner diameter of the central through-hole of the branch tube 400 is designed to accommodate 12 loosely bundled branch optical cables 200; the central through-hole diameter of the fixing tube 500 is Φ2.1mm to accommodate the main optical cable 100 with an outer diameter of 2.0mm. All parts are precision-machined to ensure dimensional tolerances.

[0030] The present invention also provides an assembly method for the above-mentioned miniature high-strength stainless steel laser-welded optical cable splitter, comprising the following steps: S1: Optical Cable Preparation and Preliminary Positioning After the 12 branch optical cables 200 are bundled together, they are secured by wrapping one loop of hot melt adhesive tape 300 and passing them together through the central through-hole of the branch tube 400. Then, the hot melt adhesive tape 300 is melted and solidified by heating to 120°C, thus fixing the branch tube 400 and the bundled branch optical cables 200 together. This pre-fixing step prevents the branch optical cables 200 from shifting relative to the branch tube 400 during subsequent operations, ensuring assembly accuracy. The main optical cable 100 is passed sequentially through the fixing tube 500 and the glue injection tube 600, and the first insertion part 501 of the fixing tube 500 is inserted into the interface structure at one end of the glue injection tube 600 to achieve insertion and fixation. At this time, the fixing tube 500 and the glue injection tube 600 form a sliding whole on the main optical cable 100.

[0031] S2: Internal Assembly and Gluing The optical fiber portions of the main optical cable 100 and the branch optical cable 200 are fused or mechanically connected to ensure optical performance. Then, the fixing tube 500 and the glue injection tube 600 are pushed towards the branch tube 400, so that the second insertion part 601 of the glue injection tube 600 is inserted into one end of the branch tube 400 until it is in place, thereby splicing the branch tube 400, the fixing tube 500, and the glue injection tube 600 into a whole. At this time, the connection point between the main optical cable 100 and the branch optical cable 200 is exactly located at the center of the optical cable junction cavity inside the glue injection tube 600. Inject sufficient epoxy resin adhesive into the internal optical cable junction cavity through the U-shaped injection hole 602 on the injection tube 600. Inject slowly until the adhesive slightly overflows from the other side of the U-shaped hole or the splice gap, indicating that the cavity is fully filled. Let it stand for a moment to allow the adhesive to level naturally and remove air bubbles.

[0032] S3: Curing and External Packaging The components are placed in a heating device and heated according to the curing process of epoxy resin adhesive to fully cure the adhesive and form a solid internal core component. Insert this inner core assembly into the outer sheath 700. Apply appropriate axial pressure to ensure that the outer sheath 700 completely covers the injection tube 600 and reaches the predetermined position; A laser welding machine is used to perform 360° circumferential scanning welding at the tail of the outer protective tube 700. The laser welding parameters are set according to the stainless steel material and wall thickness to ensure that the welding depth penetrates at least the wall thickness of the outer protective tube 700 and melts into the outer wall of the glue injection tube 600, forming a continuous and uniform fusion seal.

[0033] S4: Inspection The finished products undergo dimensional measurement, visual inspection, pull-out force testing, torsion performance testing, and optical performance testing to ensure they meet design standards.

[0034] Working principle of the invention: During assembly, the branch optical cables 200 are first bundled and passed through the branch tube 400 and pre-fixed with hot melt adhesive tape 300. The main optical cable 100 passes through the fixing tube 500 and the injection tube 600. Then, the main optical cable 100 is connected to the optical fiber of the branch optical cable 200. Next, the fixing tube 500 and the injection tube 600 are pushed towards the branch tube 400, so that the three are combined into a whole through the stepped plug-in structure. At this time, the optical cable connection point is located in the optical cable junction cavity inside the injection tube 600. Epoxy resin adhesive is injected into the cavity through the injection hole 602. The adhesive fills the cavity and wets all optical cables and the inner walls of the parts. After curing, all parts and optical cables are fixed into a whole core, achieving uniform distribution of internal stress. Finally, the core is inserted into the outer sheath 700, and the outer sheath 700 and the injection tube 600 are fused and sealed by laser welding to form an all-metal integrated protective shell.

[0035] Several points should be noted: First, in the description of this application, it should be noted that, unless otherwise specified and limited, the terms "installation", "connection" and "linkage" should be interpreted broadly, and can be mechanical or electrical connection, or internal connection between two components, or direct connection. "Up", "down", "left", "right", etc. are only used to indicate relative positional relationship. When the absolute position of the described object changes, the relative positional relationship may change.

[0036] The above description is only a preferred embodiment of the present invention. The scope of protection of the present invention is not limited to the above embodiments. Any equivalent modifications or changes made by those skilled in the art based on the content disclosed in the present invention should be included within the scope of protection set forth in the claims.

Claims

1. A miniature high-strength stainless steel laser-welded optical cable splitter, characterized in that, include: Branch tube, used to accommodate and axially position multiple branch optical cables; Fixed tube, used for axial positioning of the main optical cable; The glue injection tube is a hollow sleeve, the inner cavity of which is used to accommodate the branch tube and the fixed tube, and the two are spaced apart along the axial direction to form an optical cable junction cavity; at least one glue injection hole is opened on the side wall of the glue injection tube. The main optical cable and the branch optical cable are optically connected in the optical cable junction cavity. The inner cavity of the glue injection tube is filled with adhesive injected and cured through the glue injection hole to solidify the fixing tube, the branch tube, the main optical cable and the branch optical cable into an internal core assembly. It also includes an outer protective tube, which is sleeved on the outside of the inner core assembly and forms a tight fit with the inner core assembly. The outer protective tube is fused and sealed with the inner core assembly by annular laser welding to form an integrated packaging structure.

2. The miniature high-strength stainless steel laser-welded optical cable splitter according to claim 1, characterized in that: One end of the fixing tube is provided with a first insertion part, and one end of the glue injection tube is provided with an interface structure that is inserted into the first insertion part; The other end of the glue injection tube is provided with a second insertion part, which is used to insert and cooperate with one end of the branch tube.

3. The miniature high-strength stainless steel laser-welded optical cable splitter according to claim 1, characterized in that: The branch tube is pre-fixed to multiple branch optical cables by hot melt adhesive tape. The hot melt adhesive tape is wrapped around the outer periphery of the bundled branch optical cables and cured by high temperature, so that the branch tube and the branch optical cables are bundled and fixed as one.

4. The miniature high-strength stainless steel laser-welded optical cable splitter according to claim 1, characterized in that: The injection hole is a U-shaped hole, a circular hole, or an elongated hole, used to inject adhesive into the optical cable junction cavity.

5. A miniature high-strength stainless steel laser-welded optical cable splitter according to claim 1, characterized in that: The branch pipe, fixing pipe, glue injection pipe and outer protective pipe are all made of SUS304 stainless steel and undergo electrochemical polishing treatment.

6. A miniature high-strength stainless steel laser-welded optical cable splitter according to claim 1, characterized in that: The overall dimensions of the brancher are: length ≤ 48mm, outer diameter ≤ 8mm.

7. The miniature high-strength stainless steel laser-welded optical cable splitter according to claim 1, characterized in that: The central through-hole of the branch tube is used to accommodate multiple loosely bundled branch optical cables passing through, and the diameter of the central through-hole of the fixed tube is adapted to the outer diameter of the main optical cable.

8. An assembly method for a miniature high-strength stainless steel laser-welded optical cable splitter, based on the miniature high-strength stainless steel laser-welded optical cable splitter according to any one of claims 1 to 7, characterized in that, Includes the following steps: S1: Optical Cable Preparation and Preliminary Positioning After multiple branch optical cables are bundled together, they are wrapped and fixed with hot melt adhesive tape and passed through the central through hole of the branch tube together; the hot melt adhesive tape is heated to melt and solidify, fixing the branch tube and the branch optical cable bundle into one unit; The main optical cable is passed through the fixing tube and the glue injection tube in sequence, and the fixing tube and the glue injection tube are inserted and fixed. S2: Internal Assembly and Gluing Connect the fiber optic sections of the main optical cable and the branch optical cable; Push the fixing tube and the glue injection tube towards the branch tube so that the glue injection tube is inserted and fixed to the branch tube; Adhesive is injected into the optical cable junction cavity through the injection hole on the injection tube; S3: Curing and External Packaging The adhesive is cured by heating to form the internal core assembly; Insert the internal core assembly into the outer protective tube; A 360° circumferential laser welding is performed at the tail end of the outer protective tube to fuse and seal the outer protective tube with the glue injection tube; S4: Inspection The finished product is tested for dimensions, appearance, pull-out force, torsional properties and optical properties.

9. The assembly method of a miniature high-strength stainless steel laser-welded optical cable splitter according to claim 8, characterized in that: The adhesive is an epoxy resin adhesive.

10. The assembly method of a miniature high-strength stainless steel laser-welded optical cable splitter according to claim 8, characterized in that: The laser welding is continuous or pulsed laser welding, and the welding depth is at least through the outer protective tube wall thickness and melts into the outer wall of the glue injection tube.

Images