JP2008003178A - Fixed structure of ferrule and optical fiber cable - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fixed structure capable of fixing between a ferrule and an optical fiber in consideration of cost, operation, control and quality. <P>SOLUTION: The optical fiber cable 21 is held between a ferrule body 29 and a separable component 30. In addition, the optical fiber cable 21 is pressurized by a holding projection 46, and is also fixed without directly playing a part in laser welding. The ferrule body 29 is provided with a cable insertion hole and an aperture joint part that opens in a manner releasing a part of the cable insertion hole. The separable component 30 has a cable inserting groove and is made attachable to the aperture joint part. The ferrule body 29 and the separable component 30 constitute one and the other separation type ferrules. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a fixing structure for fixing a ferrule and an optical fiber cable, and more particularly to a fixing structure of a ferrule and an optical fiber cable that is fixed by laser welding.

  As a method of fixing a ferrule to the end of an optical fiber cable, fixing with an adhesive is generally known. Recently, fixation by welding by laser transmission welding (laser welding) has also been attempted.

  5 and 6, according to the technique disclosed in Patent Document 1 below, a transparent plastic ferrule 1 is provided, and an optical fiber cable 3 is inserted through an insertion hole 2 formed through the ferrule 1. Thereafter, the laser beam 4 is applied to and transmitted through the ferrule 1, and the inner coating 5 of the optical fiber cable 3 is absorbed to absorb the energy of the laser beam 4, and the inner coating 5 is melted. A welding state is formed with the insertion hole 2 (see the schematic laser welding portion indicated by reference numeral 6).

Reference numeral 7 indicates an optical fiber including a core 8 and a clad 9. Reference numeral 10 indicates an outer sheath of the optical fiber cable 3. The inner coating 5 is black in consideration of energy absorption of the laser beam 4. The insertion hole 2 of the ferrule 1 is formed in a stepped shape having a portion through which the optical fiber 7 is inserted and a portion through which the inner coating 5 is inserted.
JP 2002-543466 Gazette

  By the way, the above prior art has some problems. The first is that the ferrule 1 and the inner coating 5 are formed using the same material or a material having an equivalent melting point, and in consideration of weldability, There is a problem in that the degree of freedom of such selection is restricted and the cost of each of the ferrule 1 and the optical fiber cable 3 is affected.

  The second is that a gap 11 is formed between the insertion hole 2 of the ferrule 1 and the inner coating 5 of the optical fiber cable 3, and this is considered in consideration of the insertion property. Therefore, there is a problem that gap size management involving complicated work is required, which affects the work surface and the management surface.

  Here, a supplementary explanation will be given regarding the gap size management. The diameter of the portion of the ferrule 1 through which the inner coating 5 is inserted is set to be larger than the diameter of the inner coating 5 of the optical fiber cable 3, and the formation of the gap 11 is allowed. It has a structure like that. This is to ensure the insertability as described above. When the gap 11 is set to be large, the insertion property of the optical fiber cable 3 is naturally improved, but the heat transfer efficiency is deteriorated at the time of laser welding. That is, the heat of the inner coating 5 melted by the energy of the laser beam 4 is not easily transmitted to the surface of the insertion hole 2. Conversely, if the gap 11 is set small, the heat transfer efficiency will be good, but the insertion of the optical fiber cable 3 will be difficult.

  Therefore, it is necessary to manage the diameter of the portion of the ferrule 1 through which the inner coating 5 is inserted and the diameter of the inner coating 5 of the optical fiber cable 3 so that these dimensional tolerances are kept to a minimum. This is a very complicated task.

  Furthermore, the third is that the inner coating 5 is deeply melted by the energy of the laser beam 4, which is necessary for fixing the ferrule 1 and the optical fiber cable 3. There is a problem that thermal damage may occur on the side and the quality may be affected.

  The present invention has been made in view of the above-described circumstances, and provides a fixing structure of a ferrule and an optical fiber cable that can be fixed in consideration of cost, work, management, and quality. This is the issue.

  The fixing structure of the ferrule of the present invention and the optical fiber cable according to claim 1 made to solve the above-mentioned problem is one separation type ferrule made of light-transmitting resin and the other made of light-absorbing resin. A separation type ferrule is provided, and the one and other separation type ferrules are provided with a structure for sandwiching an optical fiber cable having a coating, and a laser welding portion is provided only at the contact portion between the one and the other separation type ferrules. It is characterized by setting.

  According to the present invention having such characteristics, the ferrule and the optical fiber cable are obtained by sandwiching the optical fiber cable between the one and the other separation type ferrules and performing laser welding only on the ferrule side while maintaining the sandwiched state. And fixing. According to the present invention, the fixing structure is such that only the ferrule is welded by a laser without applying laser light to the optical fiber cable side. By welding one and the other separation type ferrules, the optical fiber cable is kept in a sandwiched state, and as a result, the fixation between the ferrule and the optical fiber cable can be maintained.

  According to the present invention, the fixing structure does not require the coating of the optical fiber cable to be heat absorbing. Therefore, it becomes a fixed structure in which a general optical fiber cable can be used. Further, according to the present invention, since the optical fiber cable is sandwiched, it becomes a fixed structure that can reduce the burden on the work surface and the management surface by eliminating the gap size management between the ferrule and the optical fiber cable.

  The fixing structure between the ferrule and the optical fiber cable according to the second aspect of the present invention is the fixing structure between the ferrule and the optical fiber cable according to the first aspect. It is characterized in that a holding convex portion is formed.

  According to the present invention having such a feature, the optical fiber cable is sandwiched between the one and the other separation type ferrules, and at this time, the fixing structure capable of pressing the optical fiber cable with the holding convex portion is obtained. . According to the present invention, by pressing the optical fiber cable with the holding convex portion, the sandwiched state of the optical fiber cable is maintained in a better state, and as a result, the fixation between the ferrule and the optical fiber cable is more reliably maintained. It becomes possible to do.

  The fixing structure between the ferrule of the present invention and the optical fiber cable according to claim 3 is the fixing structure between the ferrule and the optical fiber cable according to claim 1 or 2, wherein only the one and the other separation type ferrules are used. A positioning portion is formed in the contact portion.

  According to the present invention having such a feature, due to the presence of the positioning portion, the fixing structure can smoothly perform the sandwiching operation of the one and the other separation type ferrule with respect to the optical fiber cable.

  According to a fourth aspect of the present invention, there is provided a fixing structure between a ferrule and an optical fiber cable according to any one of the first to third aspects, wherein the cable insertion hole and one of the cable insertion holes are provided. The one and the other separation type ferrules are configured by a ferrule body having an opening joint portion that opens to open the portion, and a separation part that has a cable insertion groove and attaches to the opening joint portion. Yes.

  According to the present invention having such a feature, after inserting the optical fiber cable into the cable insertion hole of the ferrule body, the separation part is attached to the opening joint portion of the ferrule body, and the optical fiber cable exposed from the opening joint portion Is inserted. And laser welding is performed only to the ferrule side which consists of a ferrule main body and a separation component, maintaining the clamping state of the optical fiber cable performed with a ferrule main body and a separation component. Thereby, the pinched state of the optical fiber cable is maintained, and as a result, a fixing structure capable of maintaining the fixation between the ferrule and the optical fiber cable is obtained.

  According to the present invention as set forth in claim 1, it is possible to fix the ferrule and the optical fiber cable better than before, which can be fixed in consideration of cost, work, management, and quality. There is an effect that a structure can be provided. Further, according to the second aspect of the present invention, there is an effect that the fixing of the ferrule and the optical fiber cable can be more reliably maintained. Further, according to the present invention described in claim 3, there is an effect that workability can be further improved. Further, according to the present invention described in claim 4, there is an effect that a more specific and reliable direction of the fixing structure can be shown.

  Hereinafter, description will be given with reference to the drawings. 1A and 1B are diagrams showing an embodiment of a fixing structure between a ferrule and an optical fiber cable according to the present invention. FIG. 1A is a perspective view of a ferrule of an optical fiber cable terminal, and FIG. 1B is a ferrule of an optical fiber cable terminal. (C) is the enlarged view of A part, (d) is a BB sectional drawing. 2 is an exploded perspective view of the ferrule, FIG. 3 is a perspective view of the ferrule in which the ferrule body is indicated by a two-dotted line, and a separation part is indicated by a solid line, and FIG. 4 is a perspective view of the ferrule.

  1A and 1B, reference numeral 21 indicates an optical fiber cable. Reference numeral 22 denotes a ferrule that is fixed to the end of the optical fiber cable 21 by welding using a laser transmission welding method (laser welding).

  In the present invention, laser welding is performed only on the ferrule 22 side and fixed, that is, laser welding so that laser welding portions 23 and 23 (see FIG. 1 (d)) are generated only on the ferrule 22 side, which will be described later. This is characterized in that the optical fiber cable 21 is fixed. Further, the present invention is characterized in that a general optical fiber cable 21 can be used and the structure of the ferrule 22 itself is different from the conventional one. Hereinafter, the structure and the like representing these features will be described with reference to FIGS.

  The optical fiber cable 21 includes an optical fiber 26 composed of a core 24 and a clad 25, and an inner coating 27 and an outer coating 28 that cover the optical fiber 26. Although the optical fiber cable 21 has been described as being general, the optical fiber cable 3 described in the conventional example (see FIG. 5). An optical fiber having a dedicated structure having an inner coating 5 in consideration of energy absorption of the laser light 4. It does not mean cable 3). In the present invention, the structure of the ferrule 22 itself can sufficiently cope with a commercially available optical fiber cable.

  The optical fiber cable 21 is subjected to terminal processing so that the optical fiber 26 and the inner coating 27 are exposed with a predetermined length. The exposed optical fiber 26 and the inner coating 27 are present inside the ferrule 22 by being fixed to the ferrule 22. Further, the end face of the optical fiber 26 is exposed at the front end position of the ferrule 22, and the end face of the outer coating 28 is brought into contact with the rear end position of the ferrule 22.

  The ferrule 22 includes one separation-type ferrule made of a light-transmitting resin and the other separation-type ferrule made of a light-absorbing resin. In this embodiment, the light-transmitting resin (transparent material) and the light-absorbing resin (heat absorbing material) are used in combination of the same resin material because the melting temperatures are the same (limited to this). is not). Examples of the light-transmitting resin (transparent material) and the light-absorbing resin (heat absorbing material) include PA12, PEI, and polycarbonate.

  The other separation-type ferrule made of light-absorbing resin will be described below as a ferrule body 29, and one separation-type ferrule made of light-transmitting resin will be described as a separation component 30 (the ferrule body 29 is made of light-transmitting resin and separated. The component 30 may be made of a light-absorbing resin (assuming no significant difference in effect).

  The ferrule main body 29 and the separation part 30 constituting the ferrule 22 become a substantially cylindrical member in an assembled state, and have an appearance shape that is not inferior to that of the known or conventional ferrule 1 (see FIG. 5). It is formed to become.

  The ferrule 22 including the ferrule main body 29 and the separation component 30 has a cable insertion hole 31 for the end of the optical fiber cable 21. The cable insertion hole 31 is formed in a stepped shape having a small diameter insertion hole 32 for inserting the optical fiber 26 and a large diameter insertion hole 33 for inserting the inner coating 27. The small diameter insertion hole 32 is configured such that this end portion opens at the front end position of the ferrule 22. The large diameter insertion hole 33 is open at the end of the ferrule 22.

  The ferrule 22 including the ferrule main body 29 and the separation component 30 is formed so that the external shape is a stepped shape. Reference numeral 34 indicates a small diameter portion, and reference numeral 35 indicates a large diameter portion. The large-diameter portion 35 is formed with annular flanges 36 and 37 at a predetermined interval. The flange 36 is disposed in the middle of the large diameter portion 35, and the flange 37 is disposed at the rear end position of the large diameter portion 35.

  The ferrule body 29 has an opening joint portion 38 that opens so as to open a part of the cable insertion hole 31. The opening joint portion 38 will be described in detail. A part of the large diameter insertion hole 33 of the cable insertion hole 31 is opened at a position from the continuous portion of the small diameter portion 34 and the large diameter portion 35 to the flange 36. An opening is formed. The opening joint portion 38 is formed so that the separation component 30 can be attached and separated before being fixed to the optical fiber cable 21.

  In the opening joint portion 38, reference numerals 39 and 39 indicate contact portions with respect to the separation component 30. The contact portions 39, 39 are formed in a planar shape. The contact portions 39, 39 are formed so as to be located on both sides of the central axis of the ferrule 22 and on the same plane. Protruding positioning portions 40 and 40 are formed in such contact portions 39 and 39.

  The protruding positioning portions 40, 40 are formed so that the separation component 30 can be smoothly guided when the separation component 30 is attached. The contact portions 39 and 39 are important portions where the laser welding portions 23 and 23 are formed when the separation component 30 is attached and fixed to the optical fiber cable 21.

  In addition to the contact portions 39 and 39, the portions denoted by reference numerals 41 and 42 can also be contact portions with respect to the separation component 30, but these contact portions 41 and 42 are portions not involved in laser welding.

  The separation component 30 is formed in a shape that is also removed from the ferrule 22 when forming the opening joint portion 38, that is, in a shape that is a substantially semi-cylindrical shape as illustrated. A cable insertion groove 43 is formed in the separation component 30. The cable insertion groove 43 includes a small diameter insertion groove 44 that becomes a part of the small diameter insertion hole 32 of the cable insertion hole 31 and a large diameter insertion groove 45 that becomes a part of the large diameter insertion hole 33.

  A plurality of holding convex portions 46 are formed in the middle of the large-diameter insertion groove 45 so as to contact and press the inner coating 27 of the optical fiber cable 21. In this embodiment, the holding convex portion 46 is formed in a substantially screw thread shape, and forms a good pressing state that bites into the inner coating 27 of the optical fiber cable 21. The holding convex portion 46 is formed to restrict movement of the optical fiber cable 21 in the pulling direction.

  On both sides of the cable insertion groove 43, contact parts 47, 47 on the separation component 30 side that are in surface contact with the contact parts 39, 39 of the ferrule body 29 are formed. The contact portions 47 and 47 are important portions where the laser welded portions 23 and 23 are formed when the optical fiber cable 21 is fixed. In such contact portions 47, 47, hole-shaped positioning portions 48, 48 are formed. Projecting positioning portions 40, 40 are inserted into and extracted from the hole-shaped positioning portions 48, 48. In the separation component 30, reference numerals 49 and 50 are portions corresponding to the contact portions 41 and 42 of the ferrule body 29, that is, contact portions.

  Next, each process regarding fixation with the ferrule 22 and the optical fiber cable 21 is demonstrated based on the above-mentioned structure.

  In the first step, an operation of inserting the optical fiber cable 21 with the terminal processed into the cable insertion hole 31 of the ferrule body 29 is performed. The optical fiber cable 21 is inserted from the large-diameter insertion hole 33 side until the end face of the optical fiber 26 is exposed at a portion that is the front end position of the ferrule 22, and the end face of the outer coating 28 is the rear end of the ferrule 22. This is done until it hits the position. When the insertion of the optical fiber cable 21 is completed, the inner coating 27 is exposed at the opening joint portion 38 of the ferrule body 29.

  In the second step, an operation of attaching the separation component 30 to the opening joint portion 38 of the ferrule body 29 is performed. Since the separation component 30 has the holding convex portion 46 in the middle of the large-diameter insertion groove 45, the separation component 30 is attached in a state in which the separation component 30 is pressed against the inner covering 27. The separation component 30 is smoothly guided to a predetermined position by the hole-shaped positioning portions 48 and 48 and the protruding positioning portions 40 and 40 of the opening joint portion 38. The separation component 30 proceeds to the next third step while maintaining the pressed state.

  In the third step, the laser beam 51 is applied to and transmitted through the separation part 30, and the energy of the laser beam 51 is absorbed by the contact parts 39 and 39 of the ferrule body 29. The operation of melting the contact portions 47 and 47 and thereby forming the laser welding portions 23 and 23 is performed. When the laser welding portions 23 and 23 are formed across the contact portions 39 and 39 of the ferrule main body 29 and the contact portions 47 and 47 of the separation component 30, a series of steps is completed. A ferrule 22 is fixed to the end of the optical fiber cable 21.

  According to the present invention, the optical fiber cable 21 is sandwiched between the ferrule body 29 and the separation component 30. Further, the optical fiber cable 21 is pressed by the holding convex portion 46. Furthermore, the optical fiber cable 21 is fixed without directly participating in laser welding. Therefore, it becomes a fixed structure that does not require the gap size management between the optical fiber cable 21 and the cable insertion hole 31, which has been conventionally required. In other words, the work structure and the management surface are better than the conventional one.

  According to the present invention, the material selection for laser welding only needs to consider the ferrule 22 side, and a general optical fiber cable 21 is used. Therefore, the fixing structure is better in cost than the conventional one.

  According to the present invention, the optical fiber cable 21 is sandwiched between the ferrule body 29 and the separation component 30 as described above. Further, the optical fiber cable 21 is pressed by the holding convex portion 46. Furthermore, the optical fiber cable 21 is fixed without directly participating in laser welding. Therefore, the optical fiber 26 does not cause thermal damage and has a fixed structure with good quality.

  In addition, it goes without saying that the present invention can be variously modified without departing from the spirit of the present invention.

  That is, not limited to the above-described shape, for example, the ferrule may be formed into a simple split shape (symmetric shape), and laser welding may be performed to fix the ferrule to the optical fiber cable.

It is a figure which shows one Embodiment of the fixing structure of the ferrule of this invention and an optical fiber cable, (a) is a perspective view of the ferrule of an optical fiber cable terminal, (b) is sectional drawing of the ferrule of an optical fiber cable terminal (C) is the enlarged view of A part, (d) is a BB sectional drawing. It is a disassembled perspective view of a ferrule. It is the perspective view of the ferrule which showed the ferrule main body with the two-dot chain line, and showed the isolation | separation components with the continuous line. It is a perspective view of a ferrule. It is sectional drawing of the ferrule of the optical fiber cable terminal used as a prior art example. It is sectional drawing of FIG.

Explanation of symbols

21 Optical fiber cable 22 Ferrule 23 Laser welding part 24 Core 25 Cladding 26 Optical fiber 27 Inner coating 28 Outer coating 29 Ferrule body (the other separation type ferrule)
30 Separate parts (one separate ferrule)
31 Cable insertion hole 32 Small-diameter insertion hole 33 Large-diameter insertion hole 34 Small-diameter portion 35 Large-diameter portion 35 Large-diameter portion 36, 37 Flange 38 Open joint 39 Contact portion 40 Protruding positioning portion 41, 42 Contact portion 43 Cable insertion groove 44 Small-diameter insertion groove 45 Large-diameter insertion groove 46 Holding convex portion 47 Contact portion 48 Hole-shaped positioning portion 49, 50 Contact portion 51 Laser light

Claims (4)

One separation type ferrule made of light-transmitting resin and the other separation type ferrule made of light-absorbing resin are provided, and a structure in which an optical fiber cable having a covering is sandwiched between the one and the other separation type ferrule A fixing structure of the ferrule and the optical fiber cable is provided, and further, a laser welding portion is set at a contact portion between only the one and the other separated ferrules. In the fixing structure of the ferrule according to claim 1 and the optical fiber cable,
A holding convex portion for the covering is formed on one of the one and the other separation type ferrules. A fixing structure of a ferrule and an optical fiber cable. In the fixing structure of the ferrule according to claim 1 or claim 2 and the optical fiber cable,
A positioning structure is formed in the contact portion between only the one and the other separation type ferrule. A fixing structure of a ferrule and an optical fiber cable. In the fixing structure of the ferrule according to any one of claims 1 to 3 and the optical fiber cable,
A ferrule body having a cable insertion hole and an opening joint portion that opens so as to open a part of the cable insertion hole, and a separation part that has a cable insertion groove and attaches to the opening joint portion, thereby A fixed structure between a ferrule and an optical fiber cable, which is a separate ferrule.

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