JP2001096570A - Ferrule and its molding method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a ferrule which can be easily mass-produced at a low manufacturing cost by injection-molding a resin material and shows high outer shape dimensional precision and also high coaxiality and a ferrule molding method. SOLUTION: The ferrule comprises a ferrule body 2 of resin having inserting holes 5a, 5b, 5c for an optical fiber terminal formed in a shaft center, a flange part 4 of resin formed protruding from the outer periphery of an intermediate part of the ferrule body 2 and an insert pipe 3 of a hard material fitted to the outer periphery of the ferrule body 2. In addition, the flange part 4 and the ferrule body 2 are joined together in one piece through a resin injection hole 7 formed in the insert pipe 3 in such a way that the insert pipe 3 is tightly held by the flange part 4 and the ferrule body 2. Further, a fitting recessed part 8 formed on an inner face at an opposite position to the resin injection hole 7 collaboratively holds the ferrule body 2 and the flange part 4 in place to the insert pipe 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a ferrule for an optical fiber connector for connecting optical cables to each other, and a method for molding the ferrule by injection molding the ferrule.

[0002]

2. Description of the Related Art Ferrules are a major component of optical fiber connectors that are expected to increase in demand in the field of optical information communication and other fields, and their quality depends on the performance, quality and cost of optical fiber connectors. Since it has a direct effect, high-performance and high-quality products are required, and in order to provide mass production at low cost, it is desirable to use an injection molded product made of a resin material.

In an optical fiber connector, a pair of ferrules each having an optical fiber projecting from a cable coating and inserted into a shaft hole are arranged in a butt state, and a metal splitting is provided on the outer periphery of a joint end thereof for positioning. Since the connection is performed with the grooved sleeve attached and the fiber strand aligned on the coaxial line, the outer diameter roundness of the ferrule to which the sleeve is attached and the axial hole through which the fiber strand is inserted Dimensional accuracy, such as concentricity with respect to the outer diameter, is required.

[0004] The conventional resin-made ferrule made by injection molding is not sufficient in terms of dimensional accuracy, particularly the roundness of the outer diameter and the coaxial accuracy of the axis with respect to the outer diameter. The uneven packing density and the heat shrinkage may cause distortion, damage the outer surface of the soft resin when attaching the sleeve, and adhere to the outer surface of the resin under the influence of static electricity. Because of this, as a result, the connection characteristics of the optical connector are degraded, such as an increase in connection loss and an amount of return loss of the end face.

For example, in Japanese Patent Application Laid-Open No. 4-298315, a ferrule molding die is proposed in which a runner is formed by a ring-shaped portion surrounding a product portion (cavity) and a centripetal portion extending from the ring-shaped portion to the product portion. The resin injected from the spool passes through the ring-shaped part and flows into the product part from the gate formed at the inner end of the centripetal part, thereby equalizing the mold temperature around the product part after injection molding. At the same time, the occurrence of non-uniform directional shrinkage is reduced, and the roundness is improved.

Japanese Patent Application Laid-Open No. Hei 8-5866 proposes a "method of manufacturing an optical fiber connector" in which a ceramic pipe is inserted into a fitting portion with a sleeve, and a ferrule body has a thermal expansion coefficient similar to that of ceramic. The ceramic pipe is inserted into a mold when the ferrule body is injection-molded and integrally molded, thereby improving dimensional accuracy and facilitating mass production, reducing costs, etc. Is being planned.

Further, the applicant of the present application has previously filed Japanese Patent Application No. 10-25 / 1990.
No. 6504, “Injection molding insert pipe and its processing method and molded article”, a cylindrical metal pipe having an outer peripheral wall provided with a communication hole formed by a polygonal opening and a petal-shaped standing piece is used as an insert member. By injecting the resin material into the pipe from the axial direction, an inner shape portion is formed in the metal pipe, and an outer shape portion is formed on the outer peripheral wall of the metal pipe with the resin material flowing out through the communication hole. We are making proposals for molded products.

[0008]

However, in the case of Japanese Patent Application Laid-Open No. 4-298315, when the injection pressure and the degree of filling are increased, abrasion occurs on the inner surface of the mold due to biting of the resin material during long-term use. There is a risk that the external dimensions of the molded product may not be able to be secured, and the frictional resistance between the inner surface of the mold and the molded product is large. There remains a problem that needs to be solved, such as that the product may be taken out in a distorted state.

In the case of Japanese Patent Application Laid-Open No. Hei 8-5866, an expensive ceramic pipe is used as an insert pipe, so that an inexpensive ferrule cannot always be provided. Since the thermal expansion coefficient is extremely small compared to the resin material such as liquid crystal polymer to be formed, there is a problem that the concentricity may decrease due to the deformation due to the thermal contraction of the resin material after injection molding. Was left.

Further, in the case of Japanese Patent Application No. 10-256504, the resin material is injected from the axial direction of the metal pipe as the insert member, so that it is difficult to increase the injection speed or increase the injection pressure. When the resin material is uniformly injected, there is a possibility that a small-diameter core pin disposed on the metal pipe axis to form a small-diameter hole for holding a fiber strand may be displaced or deformed.

The metal pipe used for the insert pipe has a communicating hole formed by a polygonal opening and a petal-shaped standing piece for forming a flange portion and integrally joining the metal pipe and the ferrule body. It is provided on the outer peripheral wall, these processing must be done by machining at present, but there is a possibility that it may not be compatible with small diameter metal pipes used for ferrules that are required to be further miniaturized in the future. Issues that needed to be resolved remained.

Therefore, the present invention proposes to solve these problems in the prior art by a new concept. The main object of the present invention is to form a ferrule with improved external dimensional accuracy and coaxiality by injection molding a resin material. It is an object of the present invention to provide a ferrule which can be mass-produced easily and inexpensively, and a molding method thereof.

[0013]

The ferrule of the present invention comprises:
A resin ferrule body provided with an insertion hole for an optical fiber terminal at the axis thereof, a resin flange formed so as to protrude from an outer periphery of an intermediate portion of the ferrule body, and a ferrule body extending from a distal end to at least a position where the flange is formed. A hard material insert pipe attached to the outer periphery, the insert pipe having a tip side outer periphery forming an insertion surface of a matching sleeve of an optical connector, and the insert pipe having inner and outer positions at a position where a flange portion is formed. The injection-molded flange portion and the ferrule main body are integrally joined by a resin material filled in the resin injection hole so as to sandwich the insert pipe, and a resin injection hole is provided in the insert pipe. A locking recess is provided on the inner surface facing the hole,
The resin material filled in the locking recess and the resin material filled in the resin injection hole cooperate to lock and hold the ferrule main body and the flange with respect to the insert pipe. (Claim 1)

In the ferrule of the first aspect, the insertion surface of the alignment sleeve of the optical connector is formed by the insert pipe made of a hard material, so that the required outer roundness and surface accuracy are easily secured, and The ferrule main body and the flange portion, which are injection-molded inside and outside the insert pipe, are integrally joined by the resin material filled in the resin injection hole and the locking recess of the insert pipe, so that they are strong in the axial direction and the circumferential direction. And the coaxial accuracy is also improved.

Another ferrule of the present invention is a resin ferrule main body having an optical fiber terminal fiber insertion wire and an insertion hole for a fiber core wire provided at the axis thereof, and is formed so as to protrude from a rear end outer periphery of the ferrule main body. A resin-made flange portion, and a hard material insert pipe attached to the outer periphery of the ferrule main body and extending to the rear from the position where the flange portion is formed, wherein the insert pipe has an outer periphery on the distal end side aligned with the optical connector. In addition to forming the insertion surface of the sleeve, the inner periphery of the rear end side forms an insertion hole for optical fiber coating, and the insert pipe is provided with a resin injection hole communicating the inside and the outside at the formation position of the flange portion, and injection molding The flange portion and the ferrule main body are integrally joined by a resin material filled in a resin injection hole so as to sandwich the insert pipe. (Claim 2)

According to the ferrule of the second aspect, the insertion surface of the matching sleeve of the optical connector is formed by the insert pipe made of a hard material, so that the required external roundness and surface accuracy can be easily secured. The ferrule main body and the flange portion, which are injection-molded inside and outside the insert pipe, are integrally joined by the resin material filled in the resin injection hole and the locking recess of the insert pipe, so that they are strong in the axial direction and the circumferential direction. And the coaxial accuracy is also improved.

In the ferrule of the second aspect, since the rear end side inner periphery forms the insertion hole of the optical fiber coating, the dimensional accuracy higher than that of the injection hole of the optical fiber coating molded by mounting the second core pin is provided. Obtained, especially for ferrules that are expected to be increasingly smaller in the future

In the ferrule of the second aspect, a locking recess is provided on an inner surface of the insert pipe facing the resin injection hole, and the resin material filled in the locking recess and the resin material filled in the resin injection hole are provided. Can cooperate to lock and hold the ferrule body and the flange portion with respect to the insert pipe. (Claim 3)

In the ferrule according to the third aspect, the ferrule body and the flange portion, which are injection-molded inside and outside the insert pipe, are integrally joined by the resin material filled in the resin injection hole and the locking recess of the insert pipe. In addition, the shaft is locked and held in the axial direction and the circumferential direction, so that the coaxial accuracy is also improved.

In the ferrule of the first or third aspect, the insert pipe may have a configuration in which the resin injection hole and the locking recess are provided at a plurality of positions on the same circumference at substantially equal intervals. it can. (Claim 4)

In the ferrule according to the fourth aspect, the plurality of resin injection holes and the locking recesses provided at substantially equal intervals on the same circumference of the insert pipe are equally formed with respect to the ferrule body 2 and the flange portion 4. , The locking and holding in the axial and circumferential directions between them can be performed more firmly without deviation.

In the ferrule of the present invention, the insert pipe may be formed of a stainless steel pipe, and the ferrule body and the flange may be formed by injection molding of a liquid crystal polymer. (Claim 5)

In the ferrule according to the fifth aspect, the stainless steel pipe is inexpensive, the processing of the resin injection hole, the locking concave portion or the locking projection is easy, and the fine surface roughness and high dimensional accuracy can be obtained by polishing. The thermal expansion coefficient of the liquid crystal polymer is close to that of the stainless steel pipe, so that the liquid crystal polymer has good compatibility with the stainless steel pipe.

According to the ferrule molding method of the present invention, an insert pipe provided with a resin injection hole on an outer periphery of an intermediate portion in an axial direction is provided.
It is mounted in a cavity formed by a fixed mold and a movable mold, and a core pin for forming an insertion hole of a fiber end is disposed at an axis of an insert pipe in this cavity. A cavity for molding is defined, and a P.I. When a molding cavity for the flange portion is defined in the vicinity of L and the resin material is injected into the molding cavity for the flange portion via the gate, the injected resin material passes through the resin injection hole of the insert pipe and the ferrule body. Of the insert pipe, and the flange formed on the outer periphery of the insert pipe and the ferrule main body formed in the insert pipe are integrally joined via the resin injection hole. (Claim 6)

According to the ferrule molding method of the sixth aspect, the resin material flowing into the insert pipe from the resin injection hole is:
The viscosity rises due to shear heat insulation generated when passing through the resin injection hole formed by the pores, the viscosity decreases and the fluidity is increased, and the jet is dispersed in a mist from the resin injection hole into the insert pipe. As a result, the ferrule main body can be injection-molded with high weld strength, high strength and high dimensional accuracy since the filling is performed quickly and uniformly.

In the method of forming a ferrule according to claim 6, a method is adopted in which a stainless steel pipe is used for the insert pipe, a liquid crystal polymer is used for the resin material, and a crystal direction of the liquid crystal polymer is aligned with an axial direction of the insert pipe. be able to. (Claim 7)

According to the ferrule molding method of the present invention, the liquid crystal polymer forming the ferrule main body and the inserted stainless steel pipe have similar thermal expansion coefficients. No stress or damage is applied, and the ferrule body has high dimensional accuracy in the axial direction along the crystal direction of the liquid crystal polymer, and the dimensional accuracy in the radial direction, which has difficulties in dimensional accuracy, is ensured by the outer dimensions of the insert pipe Is done.

According to a sixth aspect of the present invention, a resin material is injected into the molding cavity of the flange portion through a plurality of gates communicating with each other from a ring-shaped runner around the flange portion. It is possible to adopt a method in which the injected resin material is injected into the molding cavity of the ferrule main body through the plurality of resin injection holes provided on the same circumference of the insert pipe. (Claim 8)

According to the ferrule molding method of the present invention, the resin material is injected into the insert pipe from the ring-shaped runner through the plurality of gates and the plurality of resin injection holes, so that the lengths of the respective flow paths are substantially equal. And good injection molding can be performed.

In the ferrule molding method according to any one of claims 6 to 8, a first core pipe made of a non-metallic hard material to which the insert pipe is fitted is mounted in the fixed mold so as to perform injection molding. A method can be adopted. (Claim 9)

According to the ferrule molding method of the ninth aspect, the first core pipe can prevent the insert pipe from being deformed at the time of injection molding, and can have an outer diameter having a high roundness. In addition to eliminating the risk of abrasion of the insert pipe causing a decrease in the accuracy of the outer diameter, if the inner dimensional accuracy is reduced due to wear over a long period of use, replace it easily to maintain the dimensional accuracy. Can be.

In the method for forming a ferrule according to any one of claims 6 to 8, a nonmetallic metal fitting into which a tip end of a core pin for forming an insertion hole of a fiber end projecting from an axis of the insert pipe is fitted. The method of mounting the second core pipe made of the hard material described above and performing injection molding can be adopted. (Claim 10)

According to a tenth aspect of the present invention, there is provided a method for forming a ferrule.
By holding the first core pin with high coaxial accuracy at the axis of the insert pipe by the second core pipe, it is possible to form the fiber insertion hole formed by this first core pin with high coaxial accuracy at the axis of the ferrule. it can.

In the method for forming a ferrule according to any one of claims 6 to 8, a first core pipe made of a non-metallic hard material to which the insert pipe is fitted is mounted in the fixed mold. It is possible to adopt a method in which a second core pipe made of a non-metallic hard material is fitted to the distal end side of a core pin for forming an insertion hole of a fiber end projecting from an axis, and injection molding is performed. (Claim 11)

In the method for forming a ferrule according to claim 11,
The above-described effects of both the ninth and tenth aspects are obtained.

In the method for forming a ferrule according to any one of claims 9 to 11, the first core pipe and the second core pipe may be made of zirconia ceramic. (Claim 12)

In the method for forming a ferrule according to claim 12,
By using zirconia ceramic, high dimensional accuracy can be obtained, and a pipe made of zirconia ceramic, which is frequently used at present, can be used for the ferrule body, so that it can be obtained relatively inexpensively and easily.

The injection molding in the method for molding a ferrule according to any one of claims 6 to 12 can employ a method in which a resin material having low viscosity and improved fluidity is subjected to high injection speed and low injection pressure. (Claim 13)

In the method for forming a ferrule according to claim 13,
By filling the resin material at a high injection speed, it is possible to prevent the occurrence of a weld line with respect to the front end surface of the ferrule main body and to improve the accuracy of the connection end surface, and to fill the resin material at a low injection pressure to thereby form a very fine first material. The coaxiality of the wire insertion hole can be improved by preventing deformation of the core pin.

[0040]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a ferrule according to the present invention; FIG. FIG. 2, FIG. 2 is a central longitudinal sectional view along the axial direction of the ferrule, FIG. 3 is a central longitudinal sectional view of a ferrule according to another embodiment, and FIG. 4 is a central longitudinal sectional view of a ferrule according to still another embodiment. 5 is an enlarged cross-sectional view of an insert pipe used for a ferrule, FIG. 6 is a cross-sectional view of a main part of a mold apparatus used for a ferrule molding method, and FIG. 7 is an enlarged cross-sectional view of a main part of a mold apparatus. FIG. 8 is a perspective view showing an internal space in which the resin material of the mold apparatus flows, and FIG. 9 is a sectional view of a main part of another mold apparatus.

As shown in FIG. 1, the ferrule 1 has a cylindrical ferrule body 2 made of resin and a ferrule body 2
And an insert pipe 3 attached to an outer periphery of the insert pipe 3, and a resin flange portion 4 protruding from the outer periphery of the insert pipe 3.
The outer periphery of the distal end side (frontward of the flange portion 4) of the insert pipe 3 forms an insertion surface of an alignment sleeve of an optical connector, and an insertion hole 5 for an optical fiber terminal is provided at the axis. ing.

The ferrule 1 can adopt various embodiments as shown in FIGS. 2 to 4, for example. In the ferrule 1A shown in FIG. 2, the insert pipe 3A is attached to a position slightly behind the position of the flange portion 4. In the ferrules 1B and 1C shown in FIGS. 3 and 4, the insert pipes 3B and 3C are attached to the rear end, and the insert pipe 3 needs to be attached at least to the position of the flange portion 4 for the reason described later. is there.

The ferrule 1 has a wire insertion hole 5a for inserting and holding a fiber wire, a core wire insertion hole 5b for inserting and holding a fiber core, and a sheath insertion for inserting and holding a fiber coating. The insertion hole 5 of the optical fiber terminal formed by the hole 5c is provided. In the ferrules 1A and 1B, the coating insertion hole 5c is formed in the ferrule main bodies 2A and 2B.
The ferrule 1C is formed in the inner shape of the insert pipe 3C.

The insert pipe 3 has a resin injection hole 7 communicating the inside and outside with the outer periphery at an intermediate position where the flange portion 4 is formed.
And a flange portion 4 is formed so as to cover the periphery of the resin injection hole 7, and the ferrule main body 2 is formed of a resin material filled in the insert pipe 3 through the resin injection hole 7. By doing so, the ferrule main body 2 and the flange portion 4 are interconnected via the resin injection hole 7.

FIG. 5 shows the details of the insert pipe 3. The insert pipe shown in FIG.
No. 256504, which is based on the insert pipe, and has a polygonal pyramid-shaped perforating punch, in which a resin injection hole 7 is formed, and at the same time, is cut and raised in a petal shape inside the opening edge of the resin injection hole 7. Although it is a machined insert pipe having a locking projection 9, a locking recess 8 is formed at a position facing the resin injection hole 7.

The insert pipe shown in FIG. 5B is a laser-processed insert pipe in which a resin injection hole 7 is formed by irradiating a laser beam and, at the same time, a locking recess 8 is formed at a position facing the resin injection hole 7. The insert pipe of FIG. 5A is different from the insert pipe of FIG. 5A in that the locking projection 9 is not formed. In the former case, the resin injection hole 7, the locking recess 8 and the locking projection 9 are formed. In the latter case, the resin injection hole 7 and the locking recess 8 are provided.
Respectively form a locking holding portion with the resin material.

The advantage of both is that the insert pipe of FIG. 5 (a) formed by machining is more effective in terms of the joining strength between the ferrule body 2 and the flange portion 4 formed of a resin material, but the same circumference. When processing a plurality of resin injection holes 7 and locking recesses 8 in FIG. 5A, the insert pipe of FIG. 5B by laser processing is different from the structure of FIG. Is advantageous in terms of work efficiency, and the structure of FIG. 5B is particularly suitable for a miniaturized ferrule.

The insert pipe 3 must have at least one resin injection hole 7 and at least one locking recess 8 at opposite positions on the same circumference. The bonding strength for locking and holding the resin material and the resin In order to perform injection molding through the injection hole 7, it is desirable to provide the resin injection hole 7 and the locking recess 8 at a plurality of positions at opposite positions on the same circumference, respectively. The injection holes 7 need to be arranged in a dispersed state so that they do not overlap with each other. In the illustrated embodiment, the resin injection holes 7 and the locking recesses 8 are equally arranged at three positions at 120 ° intervals.

Therefore, in the case of the insert pipe 3 of FIG. 5A which is machined, the resin injection hole 7, the locking recess 8 and the locking projection 9 are formed by the laser processing of the insert pipe 3 of FIG. In the case of, the resin injection hole 7 and the locking recess 8 are
By evenly joining the ferrule body 2 and the flange portion 4 at three locations on the same circumference, the locking and holding between the two in the axial and circumferential directions is performed firmly.

As a constituent material of the ferrule 1, the ferrule main body 2 and the flange portion 4 which are injection-molded with a resin material have a small heat shrinkage and a high dimensional accuracy, and a large mechanical strength and rigidity can be obtained. It is required to have heat resistance and little change with time, and to have high fluidity and low burr generation and excellent injection moldability. For example, a resin material meeting these requirements is a liquid crystal polymer (LCP). )
And polyphenylene sulfide (PPS) can be used.

The insert pipe 3 has low heat shrinkage and high dimensional accuracy, high mechanical strength and rigidity, high heat resistance and little change with time, processing and surface polishing, etc. As a pipe material meeting these requirements, for example, stainless steel (SUS), other hard metal materials, and ceramics such as zirconia can be used.

Here, as a preferred embodiment, the insert pipe 3 is made of stainless steel (SUS) which is inexpensive and easy to process the resin injection hole 7, the locking recess 8 or the locking projection 9.
The ferrule body 2 and the flange portion 4 are injection-molded using SUS303, which is particularly excellent in machinability and obtains a fine surface roughness and high dimensional accuracy by polishing, and SUS304 which is excellent in corrosion resistance and chemical resistance. As the resin material, a liquid crystal polymer (LCP) is used because, for example, the thermal expansion coefficient is close and the compatibility with the stainless steel pipe is good.

The liquid crystal polymer has a directionality in the crystal due to the crystalline plastic, and the crystals are aligned along a direction in which the liquid flows substantially during injection molding. However, since the insert pipe 3 is attached to the outer periphery, the accuracy of the outer dimensions is ensured, and the resin injection hole 7, the locking recess 8 or the locking protrusion is formed. Since the parts 9 are integrally joined by retaining them in the axial direction, the problem with respect to the directionality of the crystal is eliminated.

The ferrule body 2 and the flange portion 4 made of a liquid crystal polymer, the insert pipe 3 made of a stainless steel pipe, and the optical fiber of the optical cable inserted into the insertion hole 5 of the ferrule body 2 all have a coefficient of thermal expansion. Because of the similarity, the ferrule 1 does not give stress or damage to the fiber strand even when the temperature changes during use as an optical connector.

As described above, in the ferrule 1, the insert pipe 3 keeps the outer diameter at the tip end of each of the ferrules 1, 1 aligned by the attachment of the sleeve constant, and the ferrule formed by resin molding with respect to the insert pipe 3. The main body 2 and the flange portion 4 are firmly locked and held through the resin injection hole 7 and the locking recess 8 or the locking projection 9.

Therefore, the outer diameter and the roundness of the ferrule 1 can be easily adjusted to desired values by polishing, and the mechanical strength and the deformation due to the temperature change and the aging change are small. It can be mass-produced and provided at low cost.

The mold apparatus 10 for manufacturing the ferrule 1 is as follows.
As shown in FIG. 6, a vertical cross section of the main part is shown. As shown in FIG. Mold 1
6 are arranged opposite to each other with the mold division surface (PL) as a boundary.

The mold apparatus 10 includes an injection molding machine nozzle 17
The resin material is injected through the spool bush 1 attached to the fixed mold plate 12.
9 and the movable mold plate 15, and the distal end side of the spool 18 is closed by a spool lock pin 19 inserted from the receiving plate 14 side into the movable mold plate 15, and a mold dividing surface (PL). Is communicated with the runner 20 extending along the line.

A part (21A) of the first core pin 21 for forming the wire insertion hole 5 in the ferrule 1 is formed in the fixed mold 13.
Is attached, and the insert pipe 3 is attached in such a manner that the distal end of the fixed-side insert piece 22 supports one end, and the base side of the first core pin 21A is in the fixed-side insert piece 22. It is supported by the support member 23, and the distal end side protrudes from the axis of the insert pipe 3.

The movable mold 16 is provided with a movable insert 25 to which a second core pin 24 forming the coating insertion hole 6 is attached. The second core pin 24 is supported by the support member 26 in the movable side insertion piece 25 on the base side.
The distal end side protrudes from the axial center of the insert pipe 3, and the first core pin 21B further protruding from the distal end is fitted with the first core pin 21A in an abutting state.

As the cavity filled with the resin material, the inside diameter of the insert pipe 3, the first core pin 21 and the second core pin 2 in the fixed mold 13 and the movable mold 16 are formed.
4 and a cavity 27 for molding the distal end side of the ferrule main body 2 formed between the outer diameter portion of the ferrule main body 2 and the second side in the movable mold 16.
A cavity 28 for molding the rear end side of the ferrule main body 2 formed between the outer diameter portion of the core pin 24 and the movable mold 1
6 is provided with a cavity 29 for molding the flange portion 4 formed between the outer diameter portion of the insert pipe 3 and the inside thereof.

These cavities are formed in a ring-shaped runner 30 provided concentrically with the insert pipe 3 along the mold dividing surface (PL) so as to surround the cavities, and a cavity 29 is provided via gates 31, 31. The cavity 29 is connected to the resin injection hole 7 of the insert pipe 3.
The ring-shaped runner 30 is connected to the spool 19 via the runner 20.

Further, slug wells (material pools) 32, 33 are provided extending from appropriate positions of the ring-shaped runner 30, for example, from positions outside the gates 31, 31 and diagonal positions of the runner 20, and are provided on the receiving plate 14 side. Ejector pin 34 for projecting the product through which the movable mold 16 is inserted
Is mounted in such a manner that the tip thereof protrudes and retracts orthogonally to the ring-shaped runner 30 and the cavity 29, and the tip side of a pressure sensor 36 such as a load cell mounted on the sensor mounting plate 35 projects into the slug well 33.

In the injection molding of the ferrule 1 using the mold apparatus 10 having the above-described structure, the resin material injected from the injection molding machine nozzle 17 transfers the runner 20 and the ring-shaped runner 30 from the spool 19 as shown in FIG. Gate 3 through
The cavities 29 and 29 are filled into the cavity 29 through the resin injection holes 7 and filled into the cavities 28 and 29.

A plurality of (for example, eight) runners 20 are provided radially in a state of being branched from the spool 19 so that mass production can be achieved.
Can communicate with the cavity 29 by a desired position and the number of the gates 31 according to the number of the gates. By arranging the positions of the gates 31 evenly, the cavity can be uniformly filled with the resin material.

The resin material flowing into the cavities 28 and 29 through the resin injection holes 7 of the insert pipe 3 becomes viscous due to a temperature rise due to shear heat generated when the resin materials pass through the resin injection holes 7 formed by the fine holes. When the resin is discharged from the resin injection hole 7 into a wide space in the insert pipe 3, it becomes a mist-dispersed jet and is filled into the cavities 28 and 29. High density and quick filling.

The resin material that has flowed into the cavities 28 and 29 is injected toward the axis of the insert pipe 3 and then flows in a direction parallel to the axis.
1 is not deformed, and the coaxial accuracy of the fiber wire insertion hole 5a formed by the first core pin 21 with respect to the insert pipe 3 is ensured.

The tip end of the ferrule main body 2 is molded in the insert pipe 3. The liquid crystal polymer as the resin material forming the ferrule main body 2 and the stainless steel forming the insert pipe 3 have similar thermal expansion coefficients. Therefore, the insert pipe 3 does not give stress or damage to the ferrule body 2 due to the difference in heat shrinkage after injection molding.

The flow path of the injection-molded resin material flows into the molding cavity 29 of the flange portion 4 from each of the ring-shaped runners 30 through the gates 31 and 31. The injection pipe 7 is injected into the insert pipe 3 from the injection hole 7, and the length of each flow path is almost equalized by passing through each of the flow paths. As a result, good injection molding with less occurrence of well dry and the like is performed. Can be.

The liquid crystal polymer as a resin material is subjected to low-speed and high-pressure filling at a low injection speed and a high injection pressure in general injection molding, but here, as a preferred embodiment, the viscosity of the resin material is extremely low. High-pressure low-pressure filling with a high injection speed and a low injection pressure in a state of increased fluidity, thereby preventing the occurrence of weld lines on the front end surface of the ferrule body 2 and at the same time, The deformation of one core pin 21 is prevented.

That is, when low-speed and high-pressure filling is performed as in general injection molding, a weld line may be generated on the tip end surface of the ferrule body 2 which is butt-connected to a counterpart ferrule. This is solved by increasing the filling speed because of the cause. If the filling pressure is high, the very fine first core pin 21 may be deformed and the coaxiality of the wire insertion hole 5a may be reduced. To prevent deformation.

FIG. 9 shows an essential part of another embodiment of the mold apparatus 37 used in the method of forming a ferrule according to the present invention. The same members as those of the mold apparatus 10 according to the previous embodiment are the same. Although the detailed description is omitted by attaching the reference numerals, a first core pipe 38 and a second core pipe 3 made of a non-metallic hard material are provided in the fixed mold 13 of the mold apparatus 37.
9 is attached.

The first core pipe 38 is a cylindrical body into which the outer periphery of a portion to be attached to the ferrule main body 2 located on the distal end side of the insert pipe 3, that is, on the distal end side from the flange portion 4 of the ferrule 1, is fitted. The second core pipe 39 is a cylindrical body into which the first core pin 21 projecting from the axis of the insert pipe 3 toward the distal end is fitted.
Numeral 9 is made of, for example, zirconia ceramic or the like, which has a small thermal expansion coefficient and high processing dimensional accuracy.

When the injection molding of the ferrule 1 is performed by using the mold apparatus 37, the deformation of the insert pipe 3 at the time of injection molding by the first core pipe 38 is prevented, so that the outer diameter dimension is high in roundness. When the insert pipe 3 is mounted in a steel mold or insert, the insert pipe 3 is scratched when the molded product is knocked out by the ejector pin 34, so that the accuracy of the outer diameter is improved. The problem that may be reduced is the first core pipe 3
8 can be solved.

On the other hand, since the second core pipe 39 can hold the first core pin 21 with high coaxial accuracy on the axis of the insert pipe 3, the fiber wire insertion hole 5 a formed by the first core pin 21 is The ferrule 1 can be formed with high coaxial accuracy on the axis.

Furthermore, the core pipes 38, 39 can be easily replaced to maintain the dimensional accuracy when the internal dimensional accuracy is reduced due to wear due to long-term use, and zirconia ceramics are usually expensive. Although it is a material, a pipe made of zirconia ceramic having the same shape as the core pipes 38 and 39 is currently widely used for this kind of ferrule itself.
Since it is relatively inexpensive and easily available, it can be diverted.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an embodiment of a ferrule 1 according to the present invention.

FIG. 2 is a central longitudinal sectional view of the ferrule 1A along an axial direction.

FIG. 3 is a central vertical sectional view of a ferrule 1B according to another embodiment.

FIG. 4 is a central longitudinal sectional view of a ferrule 1C according to still another embodiment.

FIG. 5 is an enlarged sectional view of an insert pipe used for the ferrule 1.

FIG. 6 is a sectional view of a main part of a mold apparatus 10 used in the ferrule molding method according to the present invention.

FIG. 7 is an enlarged transverse sectional view of a main part of the mold apparatus 10 in FIG. 6;

FIG. 8 is a perspective view showing an internal space in which the resin material of the mold apparatus 10 in FIG. 6 flows.

FIG. 9 is a sectional view of a main part of a mold apparatus according to another embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Ferrule 2 Ferrule main body 3 Insert pipe 4 Flange part 5 Element wire insertion hole 6 Coating insertion hole 7 Resin injection hole 8 Locking concave part 9 Locking protrusion 10 Mold device 11 Fixed side mounting plate 12 Fixed side template 13 Fixed side Mold 14 Receiving plate 15 Movable mold plate 16 Movable mold 17 Injection molding machine nozzle 18 Spool 19 Spool lock pin 20 Runner 21 First core pin 22 Fixed side insert 23, 26 Support member 24 Second core pin 25 Movable side insert Pieces 27, 28, 29 Cavity 30 Ring runner 31 Gate 32, 33 Slug well 34 Ejector pin 35 Sensor mounting plate 36 Pressure sensor

Claims (13)

[Claims] 1. A resin ferrule main body having an insertion hole for an optical fiber terminal provided at an axis thereof, a resin flange protruding from an outer periphery of an intermediate portion of the ferrule main body, and at least a flange formed from a tip end side. An insert pipe made of a hard material attached to the outer periphery of the ferrule main body up to the position, wherein the outer periphery of the tip side forms an insertion surface of a matching sleeve of an optical connector, and the insert pipe has a flange portion. A resin injection hole communicating between the inside and the outside is provided at the position where the insert is formed, and the injection-molded flange portion and the ferrule body are integrally joined by a resin material filled in the resin injection hole in a manner to sandwich the insert pipe, The pipe is provided with a locking recess on the inner surface facing the resin injection hole, and the resin material filled in the locking recess and the resin injection hole are filled. Wherein the resin material cooperates to hold and hold the ferrule body and the flange to the insert pipe. 2. A resin ferrule main body having an optical fiber terminal fiber insertion wire and a fiber core wire insertion hole provided at an axis thereof, and a resin flange portion protruding from an outer periphery of a rear end portion of the ferrule main body. A hard material insert pipe that is attached to the outer periphery of the ferrule body and extends to the rear from the position where the flange portion is formed. And the rear end side inner periphery forms an insertion hole of the optical fiber coating, the insert pipe is provided with a resin injection hole communicating the inside and outside at the formation position of the flange portion, and the injection molded flange portion and A ferrule, wherein the ferrule body is integrally joined by a resin material filled in a resin injection hole in a manner to hold the insert pipe. 3. The insert pipe is provided with a locking recess at an inner surface facing the resin injection hole, and the resin material filled in the locking recess and the resin material filled in the resin injection hole cooperate. The ferrule according to claim 2, wherein the ferrule main body and the flange portion are locked and held with respect to the insert pipe. 4. The insert pipe has a plurality of resin injection holes and a plurality of locking recesses on the same circumference.
4. The ferrule according to claim 1, wherein said ferrules are provided at substantially equal intervals. 5. The ferrule according to claim 1, wherein the insert pipe is formed of a stainless steel pipe, and the ferrule body and the flange are injection-molded with a liquid crystal polymer. 6. An insert pipe provided with a resin injection hole at an outer periphery of an intermediate portion in an axial direction is mounted in a cavity formed by a fixed mold and a movable mold, and an axial center of the insert pipe in the cavity is provided. A core pin for forming an insertion hole of a fiber end is disposed in the insert pipe, and a molding cavity for a ferrule body is defined in the insert pipe. When a molding cavity for the flange portion is defined in the vicinity of L and the resin material is injected into the molding cavity for the flange portion via the gate, the injected resin material passes through the resin injection hole of the insert pipe and the ferrule body. The ferrule molding, characterized in that the flange part formed on the outer periphery of the insert pipe and the ferrule body molded in the insert pipe are integrally joined through a resin injection hole. Method. 7. The ferrule molding method according to claim 6, wherein a stainless steel pipe is used for the insert pipe, a liquid crystal polymer is used for the resin material, and a crystal direction of the liquid crystal polymer is aligned with an axial direction of the insert pipe. . 8. A resin material is injected into the molding cavity of the flange portion from a ring-shaped runner on the outer periphery thereof through a plurality of gates communicating with each other in a facing manner, and the injected resin material is the same as that of the insert pipe. 8. The ferrule molding method according to claim 6, wherein the resin is injected into the molding cavity of the ferrule main body through a plurality of resin injection holes provided on a circumference. 9. The injection molding is performed by mounting a first core pipe made of a non-metallic hard material into which the insert pipe is fitted in the fixed mold. The described ferrule molding method. 10. A second core pipe made of a nonmetallic hard material into which a distal end side of a core pin for forming an insertion hole of a fiber end projecting from an axis of the insert pipe is fitted in the fixed side mold. The ferrule molding method according to any one of claims 6 to 8, wherein injection molding is performed. 11. A non-metallic first core pipe made of a non-metallic hard material to which the insert pipe is fitted is inserted into the fixed mold, and a fiber end projecting from the axis of the insert pipe is inserted. The ferrule molding method according to any one of claims 6 to 8, wherein injection molding is performed by mounting a second core pipe made of a non-metallic hard material into which the tip end side of the hole forming core pin is fitted. 12. The method according to claim 9, wherein the first core pipe and the second core pipe are made of zirconia ceramic. 13. The ferrule molding method according to claim 6, wherein said injection molding is performed on a resin material having a low viscosity and improved fluidity under conditions of a high injection speed and a low injection pressure.