JP4435302B2 - Multi-core ferrule - Google Patents

Description

  The present invention relates to a multi-core ferrule used for an optical connector or the like.

  In this type of ferrule, high precision dimensional accuracy is required regardless of single core or multi-core, and in particular, it is necessary to increase the outer diameter dimensional accuracy on the front side and the coaxiality between the shaft center and the outer diameter dimension. A ferrule made of zirconia is mainly used. After a molded product obtained by injection molding or compression molding a mixed material of zirconia powder and a resin material is fired, a finishing process is performed using a diamond abrasive or the like.

  Zirconia ferrules can satisfy the specifications in terms of performance such as dimensional accuracy, but they are not suitable for mass production and price reduction because they are not easy to process, and ferrules are expected to increase in demand in the future. Therefore, development of a resin ferrule by injection molding of a thermoplastic resin material that can be mass-produced and reduced in price is expected.

  Resin ferrules are easier to process than zirconia and are suitable for mass production and cost reduction, but due to thermal shrinkage of the resin material after injection molding, etc. There is a risk that the coaxiality with the outer diameter may be impaired, there are problems in performance such as dimensional accuracy, and the ultra-fine pins forming the fiber core insertion holes are bent or bent by the injection pressure of the molded resin material. There was a problem.

  In order to increase the dimensional accuracy which is a problem of this resin ferrule, for example, Patent Documents 1 and 2 include at least an outer periphery on the front side in which a core insertion hole for inserting an ultrafine optical fiber core is formed on the axis. The ferrule which extended to the flange part formed in the intermediate part and mounted | worn with the metal insert pipe and its manufacturing method are disclosed.

  The resin ferrule is manufactured by mounting an insert pipe provided with a communication hole for injecting resin at a position matching the flange portion in the mold, and forming an insertion hole for the core and covering of the optical fiber terminal. A core pin is provided at the shaft center, and a molding resin material is injected from a gate provided in the vicinity of the communication hole through the communication hole, and the entire ferrule including the flange portion is integrally formed by injection molding.

  According to this resin ferrule, the roundness of the outer circumference on the front side is ensured by inserting the insert pipe and injection molding, the outer dimension accuracy and the coaxiality are increased, and the other party through the sleeve attached to the outer circumference. Since the consistency when connecting with the ferrule is improved and the positioning accuracy with respect to the optical fiber core inserted into the core insertion hole of the shaft center is also improved, an effect of reducing transmission loss can be expected.

As for the multi-core ferrules having two or more cores and the manufacturing method of the multi-core ferrules, MT type ferrules in which the ferrule body is formed in a square shape are mainly used as in Patent Document 3, for example, but the size can be reduced. For example, Patent Documents 4 and 5 propose an SC ferrule that is formed by metal injection molding in a cylindrical shape with a ternary metal or the like.
JP 2000-84974 A JP 2001-96570 A JP-A-6-226793 Japanese Patent No. 3005754 JP 2001-356240 A

  Future optical communications are expected to increase in transmission volume and spread of two-way communications as they are introduced into ordinary households. Although cost reduction is expected, it is difficult to sufficiently meet these requirements when the conventional ferrule, which is injection-molded into a cylindrical shape, is directly multi-core.

  For example, when the injection-molded ferrules of Patent Documents 1 and 2 are made multi-core by applying the technical ideas of Patent Documents 3 and 4 and 5, the core wire of the ferrule to which a number of optical fiber core wires are attached Since the insertion holes are arranged in parallel in a separated state, there is a limit to downsizing, and it is difficult to cope with further progress in multi-core and downsizing. .

  Also, since many core pins are juxtaposed to form a large number of core wire insertion holes when resin molding is performed, the core pins are more likely to be bent or bent than in the case of a single core. If the parallelism is not maintained, the dimensional accuracy is lowered and the product performance is varied. If the quality control of the core pin is strict, the productivity may be lowered.

  In the case of MT type multi-core ferrules such as Patent Document 3, there are difficulties in miniaturization and handling, and in the case of Patent Documents 4 and 5, the material itself is expensive. In addition, much time and expense are required for sintering, degreasing and polishing after molding, and the cost becomes higher than a ferrule injection-molded with a thermoplastic resin material.

  Therefore, in order to solve these problems of the prior art, the applicant of the present application previously made it possible to further reduce the size by Japanese Patent Application No. 2002-182976 (hereinafter referred to as the prior application invention) and perform injection molding. The present inventors have proposed a cylindrical multi-core ferrule and a method for manufacturing the multi-core ferrule whose main purpose is to prevent the core pin from being bent or bent and to be manufactured inexpensively and easily.

  FIG. 1 shows a two-core ferrule 1 to which the invention of the prior application is applied, and is based on an inner cylinder formed by a resin molded portion 2 in which an optical fiber is mounted on an axis and an insert pipe 3 that holds the outer diameter of the resin molded portion 2. An outer cylinder is provided, the insert pipe 3 is mounted in the mold apparatus, and the resin molded portion 2 is injection molded to form an integrally connected inner cylinder and outer cylinder.

The resin molding part 2 is provided with a core insertion hole 4a for inserting the core part of the optical fiber in the front axis, and a sheath insertion hole 4c for inserting the coating part of the optical fiber in the rear axis. A fiber mounting hole 4 is formed in which the core wire insertion hole 4a and the sheath insertion hole 4c are in communication with each other through a tapered hole 4b.
The fiber mounting hole 4 is formed with a core insertion hole 4a so as to be compatible with a multi-core optical fiber in which two or more cores are provided in parallel in one optical fiber. In the embodiment, the core wire insertion holes 4a-1 and 4a-2 having two circular cross-sections are arranged side by side in the adjacent state so as to be compatible with the two-core optical fiber.

  FIG. 2 shows an example of a thin pin holder part for forming the core wire insertion hole, and the two core pins 5 having a conical introduction portion 5a formed at the tip with an outer diameter suitable for the core wire insertion hole 4a, It is inserted into a thin pin holder 7 having a square shape and a circular attachment hole 6 formed in the center of the shaft, and an epoxy adhesive or the like is injected into the attachment hole 6 and fixed.

The thin pin holder 7 is mounted in the fixed mold and protrudes from the opening of one side of the insert pipe 3 accommodated in the mold so that the tip side of the core pin 5 protruding from the thin pin holder 7 is projected from the axial center. A large-diameter core pin 8 that forms a tapered hole 4b and a covering insertion hole 4c is projected from the opening on the other side of the insert pipe 3 to the axial center, and the introduction portion 5a is provided in a conical groove 8a formed at the tip of the core pin 8. Fits and supports.
In the prior invention, by forming the core wire insertion hole 4a in a circular shape, the outer diameter can be reduced to meet the multi-core and miniaturization of ferrules expected in the future, and the adjacent ultrafine By arranging the core pins 5 in contact with each other, it is possible to prevent the core pins 5 from being bent or bent by the pressure of the molded resin material filled in the core pins 5 at the time of injection molding.

  However, there is still a problem that needs to be improved in the invention of the prior application. For example, in order to accurately match the optical axes of the fiber cores attached to the core insertion holes 4a, a fine pin holder can be used to make the When the base end side of the core pin is supported, it is necessary to set the mounting pitch of each adjacent core pin strictly, but the core pin mounting structure as shown in FIG.

  That is, in the case of the mounting structure in which the core pin is inserted into the circular connecting hole of the thin pin holder as shown in FIG. 2, it is necessary to process each circular hole forming the mounting hole with high accuracy and Since it is extremely difficult to set a predetermined pitch by adjustment, it is necessary to adjust the pitch after insertion.

  However, the higher the precision of the processing of each circular hole, the less the clearance to adjust the pitch, making it difficult to set the predetermined pitch, and the core pin may break when inserted into the mounting hole, Further, even when the loose hole is used, the pitch adjustment is performed in the circular hole, and the core pin may be broken during the adjustment.

An object of the present invention is to provide a high-quality multi-core ferrule with high product accuracy of a resin molded portion by injection molding, particularly high dimensional accuracy of a core wire insertion hole portion .

A multi-core ferrule according to the present invention includes a resin molded part by injection molding in which a plurality of core wire insertion holes into which a core of an optical fiber is inserted is formed in the axial center part on the front end side, and an outer peripheral part of the resin molded part A multi-core ferrule having a metal insert pipe attached to the outer cylinder, the front end side of the resin molding portion straddling the front end of the insert pipe inward and outward and on the outer peripheral side of the insert pipe And a slug pool portion of a molded resin material is formed on the outer peripheral side of the insert pipe.

In multi-core ferrules, it is possible to adopt a form in which the entire ferrule is formed by a resin molding part, but the current technology has a difficulty in outer diameter dimensional accuracy and roundness, and the yield is not good. These problems can be improved by adopting a form in which the insert pipe is integrally attached to the outer periphery of the part. Furthermore, the front end side of the resin molded portion is provided with a portion extending across the front end of the insert pipe to the outer periphery side of the insert pipe, and does not affect the dimensional accuracy of the core wire insertion hole portion. Since the slug pool portion of the molded resin material is formed on the outer peripheral side, the slug of the injection molded material does not adversely affect the dimensional accuracy of the core wire insertion hole portion.

  Hereinafter, a multi-core ferrule and a multi-core ferrule manufacturing apparatus according to the present invention will be described in detail based on the embodiments of the accompanying drawings to which the present invention is applied. In FIGS. The multi-core ferrule and its manufacturing apparatus will be described, and FIGS. 8 to 10 describe the multi-core ferrule and its manufacturing apparatus according to another embodiment.

  As shown in FIG. 3, the multi-core ferrule 11 includes an inner cylinder formed of a resin molded portion 12 on which an optical fiber is mounted on an axis, and an outer cylinder formed of an insert pipe 13 that holds the outer diameter of the resin molded portion 12. As will be described in detail later, the insert pipe 13 is mounted in the mold apparatus, and the resin molded portion 12 is injection-molded to be integrally formed with the insert pipe 13.

  The resin molding part 12 is provided with a core insertion hole 14a for inserting the optical fiber core part into the front axis, and a coating insertion hole 14c for inserting the optical fiber cover part into the rear axis. A fiber mounting hole 14 is formed in which the core wire insertion hole 14a and the sheath insertion hole 14c are in communication with each other through a tapered hole 14b.

  The fiber mounting hole 14 is formed with a core insertion hole 14a so as to be compatible with a multi-core optical fiber in which two or more cores are provided in parallel in one optical fiber. Then, in order to be compatible with a four-core optical fiber, it is formed by a core wire insertion hole 14a in which four circular holes are juxtaposed in an adjacent state to form a circular connection.

  The core wire insertion hole 14a is formed in a circular connection shape, so that the outer diameter can be reduced to adapt to the multi-core and miniaturization of the ferrule expected in the future, and the injection will be described in detail later. At the time of molding, it can be prevented from being bent or bent by the pressure of the resin material filled with the ultrafine core pin forming the core wire insertion hole 14a.

  The resin molding part 12 selects and molds a molding resin material that can obtain a desired mechanical strength and dimensional accuracy from various thermoplastic resins. It is desirable to use a liquid crystal polymer having excellent dimensional stability and good processability.

  The insert pipe 13 is provided with a small-diameter cylindrical portion 15 whose outer diameter is reduced at the front end on the front side, and a small-diameter inner peripheral surface whose inner diameter is the same as that of the small-diameter cylindrical portion 15, and an inner diameter on the rear side. The large-diameter cylindrical portion 16 is formed to form a large-diameter inner peripheral surface by expanding the diameter of the rim, and a locking portion 17 is provided on the outer periphery of the rear end side of the large-diameter cylindrical portion 16, and the The radially inner peripheral surface communicates with the tapered inner peripheral surface, and the locking portion 17 is formed with an annular groove on the outer periphery in this embodiment.

The resin molded portion 12 includes a tip tapered portion 12 a at the tip of the small diameter cylindrical portion 15, a slug reservoir portion 12 b of a molded resin material on the outer peripheral side of the small diameter cylindrical portion 15, and an inner peripheral side of the small diameter cylindrical portion 15. A small-diameter cylindrical portion 12c that forms a core wire insertion hole 14a in the axial center, and a tapered portion 12d that forms a tapered hole 14b in the axial center on the inner peripheral side of the small-diameter cylindrical portion 15 and the large-diameter cylindrical portion 16 A large-diameter cylindrical portion 12e is formed on the inner peripheral side of the cylindrical portion 16 so as to form a covering insertion hole 14c in the axial center.
The insert pipe 13 is attached to the outer peripheral surface of the resin molded portion 12 to improve the outer diameter dimensional accuracy and roundness, and the small diameter cylindrical portion 15 on the distal end side is embedded in the resin molded portion 12 straddling the inside and outside. As a result, the inner diameter accuracy of the core wire insertion hole 14a can be improved as will be described in detail later by making the outer peripheral side of the small diameter cylindrical portion 15 into the slug reservoir portion 12b of the molded resin material.

  The insert pipe 13 is provided on the outer periphery on the rear end side while ensuring a substantially constant thickness of the resin molded portion 12 on the outer periphery of the covering insertion hole 14c and the taper hole 14b by the large-diameter cylindrical portion 16 on the rear side. The locking portion 17 is effective in the case of using a multi-core ferrule as it is for an optical semiconductor module, or in manufacturing a ferrule for SC-type or ST-type butt connection using a multi-core ferrule.

  The insert pipe 13 can be used for hard metal materials such as stainless steel, titanium and fiber reinforced metal (FRM), ceramics including zirconia, and high-performance engineering plastics such as polyimide resin. When used, a metal pipe that can be easily laser-welded is desirable, and among them, a stainless steel pipe that is inexpensive, highly heat resistant, and has high rigidity and dimensional accuracy is optimal.

  In this embodiment, the insert pipe 13 uses a thick pipe material, and particularly when a stainless steel pipe is used, the outer circumference on the front side and the inner circumference and the outer circumference on the rear end side are enlarged or reduced by cutting or the like. Thus, the processing for forming the small-diameter cylindrical portion 15, the large-diameter cylindrical portion 16, and the locking portion 17 can be performed with high accuracy and relatively inexpensively.

  Next, in FIG. 4, a thin pin holder that supports the base end side of the extremely thin (for example, 0.125 mm) first core pin 18 (thin pin) forming the core wire insertion hole 14 a of the multicore ferrule. Referring to FIG. 19, the thin pin holder 19 includes a grooved plate 19A and a contact plate 19B.

  The thin pin holder 19 is provided with a receiving groove 21 on the side of the joining inner surface 20 of a rectangular plate-like grooved plate 19A. The receiving groove 21 has a plurality of (four in the illustrated embodiment) first core pins 18. Are formed in a width that can be accommodated in a parallel state, and the accommodated first core pin 18 has a depth that does not protrude from the joining inner surface 20, and the groove bottom surface of the accommodation groove 21 is formed as a flat surface.

  The contact plate 19B is a square plate formed with a flat surface on the joining inner surface 22 side, and the joining inner surface 22 is brought into contact with the joining inner surface 20 to sandwich the proximal end portion of the first core pin 18 with the grooved plate 19A. At the same time, the tip 18a side of the first core pin 18 having a truncated cone shape is protruded by a predetermined length necessary to form the core wire insertion hole 14a, and is passed through screw means (not shown). Connect together.

  In order to prevent the sink of the multi-core ferrule at the time of molding, the thin pin holder 19 is subjected to a metal plating such as nickel or a nickel alloy using a metal material such as copper having good conductivity as a base material. It is desirable to finish to a desired dimension by casting or the like.

  As will be described in detail later, the thin pin holder 19 is mounted in the mold apparatus 25 in such a manner that the distal end side of the first core pin 18 protrudes into the cavity, and has a large diameter that forms the tapered hole 14b and the covering insertion hole 14c. A tip end portion 18a of the first core pin 18 is inserted into and supported by an elliptical fitting slot 24 formed at the tip of the second core pin 23 (thick pin).

  Whether or not the first core pins 18 are arranged in the receiving grooves 21 of the thin pin holder 19 at a predetermined pitch is determined on the thin pin holder 19 before being mounted on the mold apparatus 25 or the multi-core ferrule 11 formed by trial punching. On the other hand, the measurement is performed using a high-precision optical device. If the pitch is outside the allowable range set by this measurement, the pitch is adjusted by exchanging with the core pin prepared by sorting according to the outer diameter. Then, a heat-resistant adhesive B such as epoxy is filled and fixed at the adjustment position.

  That is, a core pin having a reference outer diameter (for example, a diameter of 0.125 mm), a core pin having a slightly larger diameter and a core pin having a smaller diameter are prepared by sorting in advance according to the outer diameter. If the pitch between the first core pins 18 and 18 accommodated in the pin holder 19 is not appropriate, the pitch is adjusted by replacing with a core pin that is appropriate according to the ± of the pitch.

  In this thin pin holder 19, the slotted plate 19A and the contact plate 19B can be opened and closed instead of inserting the ultra-fine core pin into the circular hole as in the circular connecting hole of FIG. The operation of attaching and removing the first core pin 18 to and from the receiving groove 21 is easy, and an excessive external force is not applied to the first core pin 18, so that the core pin can be prevented from being broken.

  Further, since the thin pin holder 19 is joined to the grooved plate 19A and the contact plate 19B by the joined inner surfaces 20 and 22 formed on the flat surface, the dimensional accuracy difference between the two and the mold pin 25 are mounted. Even when a horizontal displacement occurs between the grooved plate 19A and the contact plate 19B due to the mounting accuracy at the time, an excessive external force is not applied to the first core pin 18 or the displacement does not occur.

  In the illustrated embodiment, the receiving groove 21 is formed as a trapezoidal receiving groove that gradually decreases in diameter toward the bottom of the groove so that the slot processing is easy. However, for example, the receiving groove 21 has a constant lateral width. The grooved plate 19 </ b> A and the contact plate 19 </ b> B can also be formed in a shape such that the back surfaces of the joining inner surfaces 20 and 22 are formed in a semicircular arc shape.

  Next, FIG. 5 is a longitudinal sectional view showing a main part of a mold apparatus 25 for injection molding a multi-core ferrule, but a fixed mold 25A is provided on one side (upper side in the drawing) of the mold dividing surface PL. A movable side mold 25B is provided on the other side (lower side in the drawing), and a nozzle mounting hole 27a into which the nozzle of the injection molding machine is inserted into the fixed side mold 25A by a locating ring 26, a fixed side mounting plate 27, or the like. Is forming.

  On the fixed side mold 25A side, a fixed side mold plate 28 superposed on the fixed side mounting plate 27 is provided, and a spool bush 30 that forms a spool 30a is attached to the fixed side mold plate 28 on the bottom side of the nozzle mounting hole 27a. At the same time, a first template 31 for mounting one side of the mold body is attached to a position adjacent to the spool bush 30.

  The movable side mold 25B is provided with a movable side mold plate 32 facing the fixed side mold plate 28 at the mold dividing surface PL, and an ejector plate 33 superposed on the movable side mold plate 32. A runner 34 is formed along the mold dividing surface PL, and a spool lock pin 29 is inserted into the spool 30a, and a second mold plate 35 for mounting the other side of the mold body is provided at a position adjacent to the runner 34. It is attached.

  FIG. 6 shows an enlarged cross-sectional view and a plan view of one side of the mold main body mounted on the first mold 31. The first mold 31 has a core block 36 for mounting the thin pin holder 19 and an insert. A cavity block 38 that forms the cavity 37 by mounting the pipe 13, and a pressing block 39 that holds the thin pin holder 19 at a position adjacent to the core block 36 are attached.

  FIG. 7 shows an enlarged plan view and a cross-sectional view of the other side of the mold body mounted on the second mold plate 35. The second mold plate 35 has a large diameter provided with a fitting slot 24 at the tip. The first and second ejectors for attaching the core block 40 to which the second core pin 23 is attached and attaching the proximal end side to the ejector plate 33 to project the molded product to the second template 35 and the core block 40. Pins 41 and 42 are inserted.

  The runner 34 is formed by a straight main runner 34 a that communicates with the spool 30 a at one end side, and a sub runner 34 b that is annularly provided on the other end side of the main runner 34 a so as to surround the cavity 37. A plurality of (four in the illustrated embodiment) gates 43 communicate between the cavities 37 in a radial manner, and air vents 44 that communicate with the sub-runners 34b are provided at positions opposed to the main runners 34a.

  In the mold apparatus 25, the insert pipe 13 is attached to the cavity 38 formed in the cavity block 38, and the first core pin 18 is supported by the thin pin holder 19 attached to the core block 36. As shown in FIG. When tightening, the tip of the second core pin 23 supported by the core block 40 protrudes into the insert pipe 13, and the tip 18 a side of the first core pin 18 is inserted and supported in the fitting groove 24.

  When a molding resin material such as a liquid crystal polymer is injected into the spool 30a from the nozzle of the injection molding machine inserted into the nozzle mounting hole 27a with respect to the mold apparatus 25 in the clamped state, the molding resin material becomes the runner 34 and the gate. The multi-core ferrule 11 shown in FIG. 3 which is filled in the cavity 38 through 43 and integrated with the insert pipe 13 is injection-molded.

  In this injection molding, the first core pins 18 for forming the core wire insertion holes 14a of the multi-core ferrule are provided in parallel with the inner surfaces of the adjacent first core pins 18 and 18 in a contact state. While the 1 core pins 18 and 18 support each other, they are prevented from being bent or bent by the injection pressure of the molded resin material.

  In addition, the flow path is narrowed to the center by the taper portion formed at the tip of the second core pin 23 with respect to the molded resin material flowing into the cavity 37 in the insert pipe 13 provided with the first core pin 18. The first core pins 18 and 18 are urged in the contacting direction to support each other, and are prevented from being bent or bent by the injection pressure of the molded resin material.

  Further, since the flow path is narrowed by the insert pipe 13 surrounding the first core pin 18, the injection speed can be increased without increasing the injection pressure, and the damage to the first core pin 18 can be reduced to bend or bend. Can be prevented, and the mold temperature can be made uniform to reduce thermal shrinkage.

  In particular, since the pitch between the adjacent first core pins 18 and 18 can be positioned with high precision by the thin pin holder 19 that supports the proximal end side of the first core pin 18, the insert pipe that defines the outer diameter dimension 13 can be used to set the outer diameter dimension, the roundness of the outer diameter, and the position of each core wire insertion hole 14a with respect to the outer diameter with high accuracy.

  Next, the multi-core ferrule 45 according to the second embodiment will be described with reference to FIG. 8. The multi-core ferrule 45 has eight core wire insertion holes 46 disposed laterally as shown in FIGS. It is formed in a row of circularly connected shapes, and is configured in the same manner as in the first embodiment except for the difference in the number of core wire insertion holes 46. However, two or more core wires can be inserted. Other embodiments in which holes are formed are also possible.

  The multi-pin ferrule 45 uses a thin pin holder 47 shown in FIG. 8A when injection molding, and the thin pin holder 47 is provided with a grooved plate 47A and a contact plate as in the case of the first embodiment. The eight first core pins 50 are accommodated in parallel in a housing groove 48 formed of 47B and formed on the inner surface side of the grooved plate 47A and having a flat bottom surface, and sandwiched by a contact plate 47B having a flat inner surface side. is doing.

  Next, the multi-core ferrule 51 according to the third embodiment will be described with reference to FIG. 9. As shown in FIGS. 9B and 9C, the multi-core ferrule 51 has eight pieces as in the second embodiment. A group of core wire insertion holes 52 in which a plurality of core wire insertion holes 52 are continuously connected in a horizontal row are arranged in two upper and lower rows in a separated state to provide a total of 16 core wire insertion holes 52. .

  The multi-core ferrule 51 uses the thin pin holder 53 shown in FIG. 9A when injection molding is performed. The thin pin holder 53 is similar to the case of the second embodiment, with the grooved plate 53A and the contact plate 53B. In addition to the grooved plate 53A, the grooved plate 53C is arranged on the outer surface side of the abutting plate 53B so as to face each other.

  The thin pin holder 53 accommodates eight first core pins 56, 56 in parallel in housing grooves 54, 55 formed on the inner surface side of the grooved plates 53A, 53C, respectively, with a flat groove bottom surface. An abutting plate 53B having a flat surface on each side is interposed in the middle.

  Although not shown, receiving grooves 54 and 55 are provided on both the inner and outer surfaces of the grooved plate 53A, and a contact plate 53B is mounted on each of the inner and outer surfaces of the grooved plate 53A to attach the first core pins 56 and 56 to each other. It is possible to adopt a form of arranging in two rows, and a form of arranging in two or more rows based on the same technical idea is also possible.

  For example, each of the grooved plates 53A and 53C is provided with receiving grooves 54 and 55 on both the inner and outer surfaces, respectively, and the contact plate is provided in the middle of each of the grooved plates 53A and 53C and at one of the two outer surface sides. When 53B is mounted, the first core pins 56 can be arranged in three rows.

  In addition, housing grooves 54 and 55 are provided on both the inner and outer surfaces of each of the grooved plates 53A and 53C, and the contact plate 53B is provided at three positions between the outer surface side of each of the grooved plates 53A and 53C and each of the grooved plates 53A and 53C. Can be arranged in four rows, and the number of first core pins can be set appropriately, and the number of core wire insertion holes can be different for each row.

  As described above, in the third embodiment, a plurality of core wire insertion holes into which a large number of optical fibers can be mounted are arranged in a horizontal row, and the core wire insertion hole groups are arranged in a plurality of rows at spaced positions. By arranging them side by side, a small ferrule having a circular cross section can be made multi-core, and the mounting pitch of each core wire insertion hole can be made with high accuracy and can be injection-molded at low cost.

  Next, the multi-core ferrule 57 according to the fourth embodiment will be described with reference to FIG. 10, and the multi-core ferrule 57 has four core wire insertion holes 58 arranged laterally as shown in FIGS. 10 (b) and 10 (c). The thin pin holder 59 shown in FIG. 10A is used when the multi-core ferrule 57 is injection-molded.

  As in the case of the first and second embodiments, the thin pin holder 59 includes a grooved plate 59A provided with an accommodation groove 60 having a flat groove bottom surface, and a contact plate 59B formed with a joining inner surface 61 on a flat surface. The four first core pins 62 are arranged at predetermined intervals with respect to the housing groove 60, and the interval holding pins 63 are arranged between the adjacent first core pins 62 and 62.

  The spacing pin 63 is substantially the same diameter as the first core pin 62, but is formed in a short length whose length matches the vertical dimension of the thin pin holder 59, and the pitch between the first core pins 62, 62 is set. It is mounted to adjust within the set reference value range, and is held together with the first core pin 62 by the grooved plate 59A and the contact plate 59B.

  Therefore, when the pitch between the first core pins 62 and 62 mounted on the thin pin holder 59 is measured by the optical device and is outside the set reference value range, the first core pin 18 in the first embodiment and Similarly, the pitch adjustment is performed by selecting an appropriate one from among the spacing pins that have slightly different outer diameters and replacing them.

  In FIG. 10, one spacing pin 63 is mounted between each first core pin 62, but it is possible to adopt a mode in which two or more spacing pins 63 are mounted. In combination with the technical idea of the embodiment, the core wire insertion holes 58 according to this embodiment may be arranged in two or more rows.

  Furthermore, the core wire insertion holes 58 in each row are mixed with a row of core wire insertion hole groups arranged continuously in a circular shape and a row of core wire insertion hole groups arranged with a space. It is possible to adopt a form in which the core wire insertion holes 58 continuously connected in a circular shape and the core wire insertion holes 58 with a space are mixed in the core wire insertion hole group of each embodiment.

  When the adjacent first core pins 62 and 62 are separated by the spacing holding pin 63 as in the fourth embodiment, the fitting slot 24 of the second core pin 23 that supports the tip side of the first core pin 62 is used. Are formed in a conical shape or a circular shape separated by a predetermined pitch.

  Therefore, according to the fourth embodiment, the ferrule provided with the core wire insertion holes into which a large number of optical fibers can be mounted can be multi-core by arranging the core wire insertion holes at a desired pitch, The mounting pitch of each core wire insertion hole can be made highly accurate and can be injection-molded at low cost.

  In addition, as one of the usage forms of this type of ferrule, it is connected in a state of abutting with the counterpart ferrule via a joining member such as a split ring, but in the case of a ferrule by current injection molding, the outer diameter dimension Insert pipes are used in the first to fourth embodiments for reasons such as difficulty in increasing accuracy and poor yield. If this point is improved, multi-cores that do not use insert pipes are used. An embodiment applied to a ferrule can also be taken.

  As is clear from the above embodiment, according to the multi-core ferrule and the multi-core ferrule manufacturing apparatus according to the present invention, downsizing of the ferrule, which is expected to increase in demand in the future as the amount of transmission information increases. In addition, it is possible to cope with the increase in the number of cores by injection molding of a thermoplastic resin material that is inexpensive and can be mass-produced.

  Also, if the core wire insertion holes in the multi-core ferrule are made into a group of core wire insertion holes that are connected in a horizontal row of circularly connected shapes, it is suitable for the use of a multi-core fiber tape in which a large number of fiber core wires are connected in a horizontal row. Further, in the illustrated embodiment, the ferrule having a circular section of 2.499 mm is illustrated, but it is also suitable for a half-size ferrule having a circular section of 1.249 mm.

It is a multi-core (two-core) ferrule according to an embodiment to which the invention of the prior application is applied, wherein (a) is a transverse sectional view, (b) is a longitudinal sectional view, and (c) is a plan view. FIG. 2 is a perspective view showing a thin pin holder to be mounted in a mold apparatus in order to injection-mold a core wire insertion hole in the multi-core (two-core) ferrule of FIG. 1. 1 is a multi-core (four-core) ferrule according to a first embodiment to which the present invention is applied, wherein (a) is a plan view and (b) is a longitudinal sectional view. 3 is a thin pin holder to be mounted in a mold apparatus for injection molding the core wire insertion hole of the multi-core (4-core) ferrule of FIG. 3, wherein (a) is a perspective view of the disassembled state, and (b) Shows the assembled state in a perspective view. The principal part longitudinal cross-sectional view of the metal mold | die apparatus which injects and molds the multi-core (4-core) ferrule of FIG. It is the elements on larger scale by the side of the cabinet block in the metallic mold device of Drawing 5, and (a) is a longitudinal section and (b) is a top view. It is the elements on larger side by the side of the core block in the metal mold | die apparatus of FIG. 5, Comprising: (a) is a longitudinal cross-sectional view, (b) is a top view. It is 2nd Embodiment to which this invention is applied, Comprising: (a) is the decomposition | disassembly state of the thin pin holder with which it mounts in a metal mold | die apparatus in order to carry out injection molding of the core wire insertion hole of a multi-core (8 core) ferrule (B) is a perspective view of a multi-core (8-core) ferrule, and (c) is an enlarged plan view of the multi-core (8-core) ferrule. FIG. 4 is a third embodiment to which the present invention is applied, in which (a) is an exploded state of a thin pin holder to be mounted in a mold apparatus in order to injection mold a core wire insertion hole of a multi-core (16-core) ferrule. (B) is a perspective view of a multi-core (16-core) ferrule, and (c) is an enlarged plan view of the multi-core (16-core) ferrule. 4A is a disassembled state of a thin pin holder mounted in a mold apparatus for injection molding a core wire insertion hole of a multi-core (4-core) ferrule according to a fourth embodiment to which the present invention is applied. (B) is a perspective view of a multi-core (4-core) ferrule, and (c) is an enlarged plan view of the multi-core (4-core) ferrule.

Explanation of symbols

11, 45, 51, 57 Multi-core ferrule 12 Resin molding part 13 Insert pipe 14 Fiber insertion hole 14a, 46, 52, 58 Core wire insertion hole 16 First core pin (thin pin)
19, 47, 53, 59 Thin pin holder 19A, 47A, 53A, 53C, 59A Grooved plate 19B, 47B, 53B, 59B Abutting plate 20, 22, 49, 61 Joint inner surface 21, 48, 54, 60 Housing groove 23 Second core pin (thick pin)
24 Fitting slot 25 Mold device 25A Fixed mold 25B Movable mold 26 Locating ring 27 Fixed mounting plate 27a Nozzle mounting hole 28 Fixed mold plate 29 Spool lock pin 30 Spool bush 30a Spool 31 First mold plate 32 Movable side plate 33 Ejector plate 34 Runner 35 Second mold plate 36, 40 Core block 37 Cavity 38 Cavity block 39 Holding block 41, 42 Ejector pin 43 Gate 44 Air vent 63 Spacing pin

Claims (1)

A resin molded part by injection molding in which a plurality of core wire insertion holes for inserting a core fiber of an optical fiber is inserted in the axial center part on the front end side, and an outer cylinder attached to the outer peripheral part of the resin molded part A multi-core ferrule having an insert pipe made of metal,
The front end side of the resin molded portion has a portion extending from the inner end to the outer end side of the insert pipe across the front end of the insert pipe, and a slug pool portion of a molded resin material is formed on the outer peripheral side of the insert pipe. A multi-core ferrule.

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