WO2011149042A1 - Resin sleeve for optical connector and optical connector member - Google Patents

Abstract

Provided is a resin sleeve for an optical connector which has a low weight and cost relative to ceramic or metal sleeves for optical connectors, which is capable of preventing the disconnection of ferrules and a sleeve by means of a simple, space-saving structure, and which does not require a sleeve holder. The cylindrical resin sleeve (1) for an optical connector coaxially holds two ferrules provided on the ends of fiber optic cables, and has a disconnection prevention structure for holding both ferrules so that when one ferrule (4) (on the left side of the drawing) is disconnected, the resin sleeve (1) is fixed to the other ferrule (4) (on the right side in the drawing). The disconnection prevention structure comprises a flange (2) formed on one end of the cylinder, and an engagement site (3a) formed on the housing (3) of the optical connector member so as to fix the resin sleeve to the other ferrule (4) by engaging with the flange (2).

Description

Resin sleeve for optical connector and optical connector member

The present invention relates to an optical connector resin sleeve for coaxially butting and holding two ferrules provided at an end of an optical fiber cable, and an optical connector member including the same.

When connecting an optical fiber cable, a part called a ferrule is attached to the end of the cable, and the ferrules are connected by an optical connector part such as a cylindrical sleeve. When a cylindrical sleeve is used, the two ferrules are coaxially butted and held inside the sleeve. At the time of connection, in order to prevent light attenuation, it is necessary to reduce the coaxiality between ferrules provided at the ends of the optical fiber cable. For this reason, it is necessary to increase the accuracy of the inner diameter dimension of the sleeve and the outer diameter dimension of the ferrule. The coaxiality means the degree to which the axes of ferrules arranged so as to have a common axis do not coincide (JISＪB 182).

Conventionally, ceramics are mainly used as a constituent material for optical connector sleeves because the above-described high precision is required. For example, in a split sleeve for optical communication that has an axial slit leading from one opening of a cylindrical body to the other opening and connects optical fibers inserted through both openings, the sleeve is made of zirconia, alumina, nitriding A material formed of ceramics having crystal grains mainly composed of silicon, silicon carbide, aluminum nitride, cordierite, mullite, or the like has been proposed (see Patent Document 1). The sleeve is formed by electroforming, and has a first ferrule having an optical fiber insertion hole and a second ferrule having an optical fiber insertion hole positioned coaxially with the optical fiber insertion hole of the first ferrule. Furthermore, an optical fiber connector structure having a protective sleeve formed by electroforming to cover these ferrules has been proposed (see Patent Document 2).

Since the sleeve has a cylindrical shape, when one ferrule is pulled out from a state where two ferrules are held, the ferrule and the sleeve are interlocked by frictional force and the like, and the sleeve also comes out of the other ferrule. May occur. In order to prevent the sleeves from coming off together, a sleeve holder or the like is provided to fix the sleeve. For example, there has been proposed a member in which a cylindrical engaging member of a sleeve holder is provided with a positioning engagement portion for restricting the rotation of the center of the split sleeve (see Patent Document 3). In addition, in order to reduce the cost by reducing the number of parts without using a sleeve holder, a member for storing the split sleeve by abutting two half-sleeve storage portions that accept and support substantially half of the split sleeve has also been proposed. (See Patent Document 4).

In recent years, in the automobile field, the demand for high-capacity information transmission in the vehicle has increased due to an increase in the amount of data handled by car navigation systems and AV devices mounted on the vehicle. The adoption of is considered. Further, in the automobile field, energy saving is progressing, and the adoption of the above optical fiber is also studied for the purpose of reducing the weight. Because of the increase in the amount of information transmitted, the optical fiber is made of glass used for optical communication from the conventional plastic, and the core diameter is required to be smaller. Therefore, the inner diameter dimension of the sleeve and the outer diameter dimension of the ferrule are further increased. High precision is required. In addition, since the optical connector component in the case of using the optical fiber is required at a rate of about one for every 20 m of the optical fiber cable, when the optical fiber cable is lengthened, the weight reduction is hindered. Therefore, a compact and light-weight structure is required as compared with conventional optical connector parts for communication, and studies such as downsizing, thinning, and resinization of sleeves are underway.

As a sleeve formed of resin, for example, a hollow cylindrical plastic split sleeve provided with a slit of a certain width on the side surface, and the flow direction of the resin when the resin is injection-molded and the physical property values in the vertical direction A sleeve comprising a resin composition having a resin anisotropy value represented by a ratio of 1.5 or less has been proposed (see Patent Document 5). In addition, assuming that the sleeve is formed of a plurality of materials, the first sleeve (inner diameter side) into which the ferrule is inserted is made of ceramics or resin, and the second sleeve (outer diameter side) covering the outside of the first sleeve is made of metal. An optical fiber connector has also been proposed (see Patent Document 6).

Also, in applications where there are vibrations, such as in-vehicle use, when holding two ferrules coaxially with a sleeve, the ferrule tips are held in contact with each other with a certain gap (fine gap) between them. It prevents chipping caused by On the other hand, if the gap is too large, or if the gap width fluctuates, light attenuation occurs at the joint, so the axial length of the sleeve is used to position the ferrule tip in the axial direction. High accuracy is also required for the axial dimension (also referred to as width dimension) of the sleeve.

JP 2004-347857 A International publication WO2003 / 104871 JP 2010-197739 A JP 2001-91791 A Japanese Patent Laid-Open No. 9-318842 JP 2002-250840 A

However, in the case of using ceramics as in Patent Document 1, it is possible to reduce the thickness and increase the accuracy, but the cost of materials and processing increases. In addition, in the ceramic alone, vibrations and impacts from the outside are also transmitted to the inner diameter holding the ferrule, which may affect light attenuation. Further, the ceramic alone is heavy, and as described above, connector parts are required at a rate of about one for every 20 m of the optical fiber cable. Therefore, when the optical fiber cable is lengthened, the weight reduction is hindered. In particular, in the case where an optical fiber cable is loaded, ceramics is not preferable because the above-mentioned vibration and weight problems become significant. Moreover, when the rigidity of the sleeve is high, the ferrule side may be deformed when the ferrule is inserted, and the misalignment between the cables may increase.

Further, when the protective sleeve is formed only by electroforming as in Patent Document 2, it is necessary to increase the thickness in order to ensure the strength of the connector, and the processing time becomes longer, resulting in an increase in cost. Similarly to Patent Document 1, when only electroforming is used, there is a possibility that the inner diameter is affected by vibration or impact, and the weight is increased.

In addition, when a sleeve holder as in Patent Document 3 is provided to prevent joint omission, the number of components increases, making it difficult to reduce the size and cost of the optical connector member. In addition, as in Patent Document 4, when the shape is such that two members having a sleeve storage portion are combined instead of using a sleeve holder, the structure is complicated, and miniaturization and cost reduction are still sufficient. Can't plan.

Also, as in Patent Document 5, when the sleeve is made of resin, unlike ceramic, it is necessary to secure a contact portion with a gate portion and an ejector pin at the time of injection molding, and thinning is not easy. When the material is a resin, it is difficult to secure high dimensional accuracy, although the problem of weight reduction can be solved. Patent Document 5 describes that high accuracy can be achieved with respect to the inner diameter, thickness, outer diameter roundness, etc. of the sleeve, but sufficient accuracy cannot always be achieved with respect to the axial dimension of the sleeve. Absent. As described above, in the case where the axial position of the ferrule tip is positioned in the axial direction of the sleeve, it is particularly important to improve the accuracy of the dimension in the sleeve axial direction. The technique of Patent Document 5 does not position the tip end of the ferrule in the axial direction with a sleeve as shown in FIG.

Further, as in Patent Document 6, when the first sleeve is made of ceramics and the second sleeve is made of metal, similarly to Patent Document 1, the cost of materials and processing is high, and the inner diameter due to vibration or impact is increased. There are problems such as influence and weight increase.

The present invention has been made to deal with such problems. Resin sleeve for optical connectors that can reduce the weight and cost compared to the case of ceramics or metal, and can prevent the ferrule and sleeve from slipping out with a simple and space-saving structure that does not require a sleeve holder. The purpose is to provide. In addition, the optical connector resin with excellent dimensional accuracy that can reduce the tip of the ferrule tip and loss of optical communication in the configuration in which the axial direction of the ferrule tip is positioned as required by the axial length of the sleeve. An object is to provide a sleeve.

The resin sleeve for an optical connector of the present invention is a cylindrical resin sleeve for an optical connector for holding two ferrules provided at the end of an optical fiber cable so as to be coaxially butted, and the resin sleeve. Has a common slip-off preventing structure in which the resin sleeve is fixed to the other ferrule side when the one ferrule is pulled out from the state where the two ferrules are held. In the resin sleeve, the structure A in which the cylindrical thickness of the portion where the other ferrule is fitted and held is thicker than the cylindrical thickness of the portion where the one ferrule is fitted and held, and (2) the resin A flange formed on one cylindrical end of the sleeve, and an optical connector housing that engages with the flange and fixes the resin sleeve to the other ferrule side. Kicking, characterized in that at least one structure selected structure B from consisting of the engagement site.

The resin sleeve has the structure A. In the structure A, the cylindrical inner diameter of the resin sleeve or the cylindrical outer diameter of the resin sleeve is constant in the axial direction.

The resin sleeve has the structure B, and in the structure B, the engagement portion of the housing is in contact with the end surface on the opposite side in the axial direction of the end surface of the flange that is the cylindrical end surface of the resin sleeve. It is characterized by.

The resin sleeve has the structure B and is injection-molded by providing a gate portion on the flange. Further, the gate portion is provided on an outer diameter surface of the flange, an end surface of the flange serving as a cylindrical end surface of the resin sleeve, or an end surface of the flange opposite to the axial direction of the end surface. And

The resin sleeve has a contact portion with an ejector pin at the time of injection molding on the flange. Further, the resin sleeve has the contact portion on an end surface of the flange which is a cylindrical end surface of the resin sleeve or an end surface of the flange on the opposite side of the end surface in the axial direction.

The resin sleeve is provided with a gate portion on one cylindrical end surface and is injection-molded using a resin, and after that, at least a cylindrical end surface including the gate portion is additionally processed to have a surface having no convex portion with respect to the axial direction. In the resin sleeve, the fitting portions of the two ferrules are respectively fitted to the cylindrical inner surface, and the ferrule tips in the sleeve are in contact with the ferrules on the cylindrical end surfaces. The axial positioning of the part is performed.

In the resin sleeve, the gate portion is removed by the additional processing.

The above-mentioned additional machining is machining. Further, the machining is a grinding process. In particular, the grinding process is a lapping process.

The above additional machining is non-contact machining. Further, the non-contact processing is laser processing.

The resin forming the resin sleeve is a liquid crystalline resin or a polyetherimide resin. Further, the ferrule is made of resin, and the resin forming the resin sleeve is the same resin as that forming the ferrule.

In the resin sleeve, a frictional force between a cylindrical inner surface of a portion where the one ferrule is fitted and held and a fitting surface of the ferrule is a cylinder inner surface of a portion where the other ferrule is fitted and held. It is smaller than the frictional force with the fitting surface of the ferrule.

The optical connector member of the present invention includes a housing, two ferrules provided at the ends of different optical fiber cables, and a cylindrical sleeve that fits and holds these ferrules coaxially on the cylindrical inner surface. Thus, the sleeve is a resin sleeve for optical connectors according to the present invention.

The resin sleeve for an optical connector of the present invention has a structure that prevents the resin sleeve from being fixed to the other ferrule side when one ferrule is pulled out from a state in which two ferrules are held. (1) In the resin sleeve, the structure A in which the cylindrical thickness of the portion where the other ferrule is fitted and held is thicker than the cylindrical thickness of the portion where the one ferrule is fitted and held, and (2) A flange formed on one cylindrical end of the resin sleeve, and an engagement portion in the housing of the optical connector that engages with the flange and fixes the resin sleeve to the other ferrule side. Since the structure B is at least one structure selected from the structures B, it is possible to prevent the ferrule and the sleeve from slipping out with a simple structure that does not require the sleeve holder. Further, since it is made of resin and does not use a sleeve holder, the optical connector member using the sleeve can be reduced in size (space saving), reduced in weight, and reduced in cost.

In addition, when a flange is formed on a resin sleeve to prevent joint pull-out, even if it is a thin cylindrical resin sleeve, the flange is provided with a contact portion with an injection molded gate portion or an ejector pin. It becomes possible to manufacture by injection molding.

Further, the fitting portions of the two ferrules are respectively fitted to the inner diameter surface of the cylinder, and contacted with the respective ferrules at the respective cylindrical end surfaces, thereby positioning the ferrule tip portion in the sleeve in the axial direction. In the resin sleeve for optical connectors, the cylindrical end surface that comes into contact with the ferrule is an additional machined surface by machining or the like, so the dimensional accuracy of the sleeve in the axial direction is excellent. For this reason, the fluctuation | variation of the clearance gap between the front-end | tip parts of a ferrule can be suppressed, and the loss of the optical communication in the chip | tip of the ferrule front-end | tip part by a contact or a junction part can be reduced.

Further, since the resin-made sleeve for optical connectors is made of resin, it can be reduced in weight and cost as compared with the case where it is made of ceramic alone. Further, the surface is cylindrical, and is provided with a gate portion on one cylindrical end surface and is injection-molded using a resin. Then, a cylindrical end surface including at least the gate portion is additionally machined to have no convex portion in the axial direction. Therefore, it is possible to prevent the formation of gate marks and burrs on the inner diameter surface of the cylinder, and the orientation of the filler contained in the resin is the axial direction, and the dimensions of the inner and outer diameters of the cylinder due to resin sink marks during injection molding. Decrease in accuracy can be prevented. As a result, the misalignment and angular misalignment of the optical fibers to be connected are small, the coaxiality between the optical fibers is sufficiently small, and the loss of optical communication at the joint can be reduced.

It is sectional drawing which shows an example of resin-made sleeves. It is sectional drawing which shows the other example of resin-made sleeves. It is a figure which shows only the resin sleeves (with a flange) in FIG. It is sectional drawing which shows the gate part at the time of injection molding of resin sleeves. It is sectional drawing which shows the ejector pin at the time of injection molding of resin sleeves. It is a figure which shows the other example of the sleeves made from resin. It is a figure which shows the other example of a gate part. It is a figure (sectional view) which shows the resin sleeve which has a flange. It is sectional drawing which shows an optical connector junction part. It is sectional drawing which shows an example of the resin ferrules for optical connectors. It is a reference figure which shows the relationship between the length of a strand insertion hole, and the twist of an optical fiber strand. It is sectional drawing which shows an optical connector junction part. It is sectional drawing which shows the other example (with a metal core) of the resin ferrules for optical connectors. It is sectional drawing which shows the other example (there is a metal part in the internal peripheral surface of a strand insertion hole) of the resin-made ferrules for optical connectors. It is sectional drawing which shows the other example (the metal part exists in the inner peripheral surface of a core wire insertion hole) of the resin-made ferrules for optical connectors.

The resin sleeve for an optical connector of the present invention is a cylindrical shape for holding two ferrules provided at the end of an optical fiber cable so that they are coaxially abutted, and one ferrule from a state in which two ferrules are held. When pulling out, it has a structure that prevents the resin sleeve from being fixed to the other ferrule side. Here, the common omission prevention structure is the following structure A, structure B, or a combination thereof.
Structure A: In the resin sleeve, the cylindrical thickness of the portion where the other ferrule is fitted and held is thicker than the cylindrical thickness of the portion where the one ferrule is fitted and held Structure B: The resin sleeve A structure comprising a flange formed at one cylindrical end and an engagement portion in the housing of an optical connector that engages with the flange and fixes the resin sleeve to the other ferrule side

Further, the optical connector member of the present invention is a cylindrical present invention in which the housing and two ferrules respectively provided at the ends of different optical fiber cables are fitted and held together by abutting these ferrules coaxially on the cylindrical inner surface. A resin sleeve for optical connectors.

An example of the resin sleeve for an optical connector of the present invention will be described in detail with reference to FIG. FIG. 1 is a cross-sectional view showing an optical connector joint portion of an optical connector member using a resin sleeve having a common omission prevention structure A. FIG. As shown in FIG. 1, the resin sleeve 1 is fitted with fitting portions 4 a of a pair of ferrules 4 on its cylindrical inner surface, and holds the pair of ferrules 4 in a state of being abutted coaxially. . Further, the cylindrical end surface of the resin sleeve 1 is in contact with the stepped surface of the fitting portion 4 a of each ferrule 4, and the distal end portion of the ferrule in the resin sleeve 1 is positioned in the axial direction. The tip of the ferrule 4 is in a state of being abutted with a slight gap in order to prevent chipping due to contact.

Each ferrule 4 is provided at an end portion of an optical fiber cable, an optical fiber core wire 6 is inserted into a main body portion, and an optical fiber strand 5 is passed through a strand insertion hole 4b at a distal end portion. The optical fiber 5 is an optical fiber made of quartz glass (for example, 0.125 mm diameter) coated with an ultraviolet curable resin (for example, 0.25 mm diameter). The wire is further coated with a resin or the like. The strand insertion hole 4b is circular and has a hole diameter (about +1 to 20 μm) slightly larger than the diameter of the optical fiber strand 5. Within the ferrule, the optical fiber 5 and the optical fiber 6 are fixed to the respective insertion holes via an adhesive. By holding the pair of ferrules 4 in a state of being coaxially butted on the cylindrical inner surface of the resin sleeve 1, the wire insertion holes 4 b at the tip of the ferrule 4 are connected in a state where they coincide on the same axis.

The resin sleeve 1 has a cylindrical wall thickness of a portion 1a in which the right ferrule 4 in the drawing is fitted and held as a structure for preventing the slipping out, and a portion 1b in which the left ferrule 4 in the drawing on the drawing side is fitted and held. The structure A is thicker than the cylindrical wall thickness. Here, the portion where the ferrule 4 is fitted and held is the entire portion that is in direct fitting contact with each ferrule 4 in the axial direction of the resin sleeve 1. Further, the thickness of 1a and 1b may not be constant in the axial direction. When 1a is thicker than 1b, the thickness of the thinnest portion of 1a is larger than the thickness of the thickest portion of 1b. I hope. Therefore, for example, the resin sleeve 1 may be a tapered cylindrical member that is continuously thinned from the cylindrical end surface on the 1a side toward the cylindrical end surface on the 1b side. The difference in thickness is at least a difference that can cause a difference in the fixing force of a ferrule to be described later and prevent the joint from coming off. From these points, the flange shape (structure B) in which only a part of the part fitted and contacted with one ferrule is thick and the thickness of the other part is the same is the structure A. Not included.

In the embodiment shown in FIG. 1, the cylindrical inner diameter of the resin sleeve 1 is constant in the axial direction (the inner diameter is the same for 1a and 1b), and the outer diameter of the cylinder is 1a by making a difference about half of the axial direction as a boundary. The cylindrical wall thickness is made thicker than the cylindrical wall thickness of 1b. With this structure, the stress on the inner surface of 1a is larger than the stress on the inner surface of 1b. For this reason, when a ferrule having the same diameter is press-fitted and fitted, the inner diameter surface of 1a is fixed to the ferrule by the inner diameter surface of 1b even if the cylindrical inner diameter of the resin sleeve 1 is constant in the axial direction. It becomes larger than the force to fix. In addition, the fixing force is schematically represented by a white arrow in the figure. Due to this difference in fixing force, when the ferrule 4 on the 1b side is pulled out from the state where the two ferrules are held, the resin sleeve 1 is fixed to the ferrule 4 side on the 1a side, and the resin sleeve 1 is attached to the 1b side ferrule 4 side. In conjunction with the ferrule 4, it is possible to prevent a common omission that comes off the ferrule 4 on the 1a side. As a result, only the ferrule 4 on the 1b side is pulled out from the resin sleeve 1 (the lower diagram in FIG. 1). In this way, it is possible to prevent joint slippage with a simple structure that does not require a sleeve holder.

As another aspect, the cylindrical outer diameter of the resin sleeve 1 is constant in the axial direction (the outer diameter is the same for 1a and 1b), and the cylindrical inner diameter is given a difference at approximately half the axial direction as a boundary. The cylindrical wall thickness of 1a may be thicker than the cylindrical wall thickness of 1b. In this case as well, the force by which the inner diameter surface of 1a fixes the ferrule is larger than the force by which the inner diameter surface of 1b fixes the ferrule, so that it can be prevented from coming out together.

In the resin sleeve 1, the frictional force between the cylindrical inner surface of the portion 1 b where one ferrule 4 (left side in the figure) is fitted and held and the fitting surface of the ferrule 4 is determined as the other ferrule 4 (right side in the figure). It is preferable to make it smaller than the frictional force between the cylindrical inner surface of the portion 1 a to which is fitted and held and the fitting surface of the ferrule 4. For example, the surface roughness of each cylindrical inner surface can be changed, or a low friction coating can be formed only on the cylindrical inner surface of 1b. Examples of the low friction coating include an oxide coating and a diamond-like carbon coating. Such a configuration that gives a difference in frictional force can also be applied to the case of a joint slip prevention structure B described later.

Another example of the resin sleeve for optical connectors of the present invention will be described in detail with reference to FIGS. FIG. 2 is a cross-sectional view showing an optical connector joint using a resin sleeve having a common slip prevention structure B, and FIG. 3 (a) is a front view seen from the end face side of the resin sleeve. 3 (b) is a cross-sectional view taken along line AA in FIG. 3 (a). As shown in FIG. 2, this resin sleeve 1 has a flange 2 formed at one end of a cylinder and a ferrule 4 side that engages with the flange 2 (the right side in the figure) as a common slip-off preventing structure. It has a structure B consisting of an engagement portion 3a in the housing 3 of the optical connector for fixing the resin sleeve 1 to the housing. Other configurations such as the ferrule 4, the optical fiber 5 and the core 6 are the same as those shown in FIG. As shown in FIGS. 3 (a) and 3 (b), the flange 2 is a stepped portion (saddle portion) projecting toward the cylindrical outer diameter side formed at one cylindrical end portion. In the resin sleeve 1, the cylindrical thickness other than the portion where the flange 2 is formed is constant in the axial direction.

In addition to the shape shown in FIG. 2, the flange 2 and the engagement portion 3 a of the housing 3 have a shape that can prevent the resin sleeve 1 from coming out with the ferrule 4 on the drawing side (left side in the figure). I just need it. In the embodiment shown in FIG. 2, when the ferrule 4 on the drawing side (left side in the drawing) is pulled out from the state where two ferrules are held, the end surface 2 a of the flange 2 comes into contact with the engaging portion 3 a of the housing 3. The resin sleeve 1 is fixed to the middle right ferrule 4 side, and the resin sleeve 1 interlocks with the ferrule 4 on the drawing side (left side in the figure) to prevent the joint slipping out of the right ferrule 4 in the figure. it can. As a result, only the ferrule 4 on the extraction side (left side in the figure) is extracted from the resin sleeve 1 (the lower figure in FIG. 2). As shown in FIG. 3, the end surface 2 a of the flange 2 is an end surface on the opposite side in the axial direction of the end surface 2 b of the flange 2 that becomes the cylindrical end surface of the resin sleeve 1.

By using an existing stepped portion or the like in the housing 3 as the engaging portion 3a, it is possible to provide a structure that prevents the joint from slipping out by simply forming the flange 2 that is a simple structure on the resin sleeve 1 side. In this case, not only a sleeve holder for holding the sleeve is unnecessary, but also the housing side of the optical connector is not required to be processed, and the cost can be further reduced.

As shown in FIG. 4, the resin sleeve 1 having a flange is formed by injection molding, for example, by providing a gate portion 7 on the flange 2. The gate portion 7 includes an outer diameter surface 2c of the flange 2 (FIG. 4A), an end surface 2b of the flange 2 serving as a cylindrical end surface of the resin sleeve (FIG. 4B), or an axial direction of the end surface 2b. It is preferable to provide on the end surface 2a of the flange 2 on the opposite side. Since the gate portion 7 is provided on the end face 2b or the like, the gate structure is a pinpoint gate / side gate. Moreover, in order to ensure the roundness of the resin sleeve 1, it is preferable to use a multipoint gate arranged at a predetermined interval.

As shown in FIG. 4A, in the resin sleeve 1, the gate portion 7 is provided on the outer diameter surface 2c of the flange 2 and injection molding is performed, so that no gate mark is formed on the end surface 2b of the flange 2 on which the ferrule hits. Even with no additional machining, the axial dimension can be improved with high accuracy. Further, as shown in FIG. 4B, even when the gate portion 7 is provided on the end surface 2b of the flange 2, the gate mark is removed by an additional process or the like described later, and the axial dimension can be increased in accuracy. .

As shown in FIG. 5, the resin sleeve 1 having the flange 2 preferably has a contact portion with the ejector pin 8 at the time of injection molding. In FIG. 5, the end surface 2 a on the opposite side in the axial direction of the end surface 2 b of the flange 2 serving as the cylindrical end surface of the resin sleeve 1 is used as the contact portion, but the end surface 2 b of the flange 2 serving as the cylindrical end surface of the resin sleeve 1 is applied. It is good also as a contact part. Usually, when the resin sleeve 1 is injection-molded, it is difficult to form a thin cylinder because it is difficult to secure a contact portion with the ejector pin. On the other hand, by forming the flange 2 in the resin sleeve 1 and receiving the ejector pin 8 at the end face 2a or 2b of the flange 2, the protrusion can be made even when the portion other than the flange 2 is made thin. It becomes.

When the resin sleeve 1 has a structure A in addition to the structure B as a common slip-off preventing structure, the flange 2 is provided with a contact portion between the gate portion 7 and the ejector pin 8 for injection molding ( After that, the flange is removed by an additional process, and a thin resin sleeve without flange can be manufactured. This method is effective when the flange shape is not possible depending on the application.

In the resin sleeve 1, it is preferable that the ratio (L / D) of the cylindrical length (L) to the cylindrical outer diameter (D) is 2 or more. The cylindrical outer diameter (D) is the average cylindrical outer diameter in the axial direction when there is a difference in thickness and the outer diameter is not constant in the axial direction. Is the diameter. By setting L / D to be 2 or more, it is easy to maintain the coaxiality of the ferrules held on the cylindrical inner surface. Note that if the cylindrical length L is too large, the length of the corresponding ferrule needs to be increased, and it may be difficult to perform processing while maintaining the accuracy of the ferrule. Therefore, L / D is set to 2 to 4. It is more preferable. The cylindrical thickness of the resin sleeve 1 is preferably 0.3 to 0.6 mm for the purpose of maintaining strength.

The resin sleeve 1 of the present invention is formed by resin injection molding or the like. As the resin material, a known resin used for a resin sleeve can be used. A resin excellent in injection moldability that hardly generates burrs or the like is preferable. In addition, a resin having a large elastic modulus and excellent dimensional stability with respect to a temperature change is preferable in order to be usable for an in-vehicle optical fiber cable used in a wide temperature range (about −40 ° C. to 90 ° C.). Examples of the resin that can be used in the present invention include crystalline resins such as liquid crystal resin (LCP), polyphenylene sulfide (PPS) resin, polyether ether ketone (PEEK) resin, polyacetal (POM) resin, and polyamide (PA) resin, Alternatively, amorphous resins such as polyetherimide (PEI) resin, polyphenylsulfone (PPSU) resin, polyethersulfone (PES) resin, polyphenylene ether (PPE) resin, and polyamideimide (PAI) resin can be used. . Among these resins, it is preferable to use a liquid crystal resin or a polyetherimide resin.

Examples of liquid crystal resins include aromatic polyester resins, aromatic polyesterimide resins, and aromatic polyesteramide resins that can form an anisotropic molten phase. Examples of the aromatic polyester resin include those having units represented by the following chemical formulas 1 to 3. Since it is excellent in heat resistance, the wholly aromatic polyester resin of Chemical formula 1 is particularly preferred. Since the liquid crystal resin exhibits liquid crystallinity in a molten state, it has good fluidity during molding and can be easily molded even if the resin sleeve 1 is thin.

　上式において、ｎは０または１を、ｘ、ｙ、ｚはそれぞれ任意の整数を表す。

In the above formula, n represents 0 or 1, and x, y, and z each represents an arbitrary integer.

Other than that, a liquid crystal resin that forms an anisotropic melt phase, for example, a resin system that exhibits thermotropic liquid crystallinity can be used.

The polyetherimide resin is a thermoplastic resin having an imide bond and an ether bond in the molecule, has a high elastic modulus, and is excellent in workability (injection moldability). It is suitable as a resin material for the resin sleeve 1.

The above resin materials can be blended with known fillers for the purpose of preventing sink marks during injection molding and improving mechanical strength. Examples of the filler that can be used in the present invention include inorganic fillers such as glass fibers, carbon fibers, glass beads, graphite, zinc oxide, potassium titanate, magnesium oxide, titanium oxide, and graphite. These fillers are blended within a range that does not lower the fluidity of the resin. As shown in FIG. 4 and FIG. 6 to be described later, in the resin sleeve, when the gate portion is provided on the flange or the cylindrical end surface and injection molding is performed, the orientation of the filler in the resin sleeve is the axial direction. Thereby, the fall of the dimensional accuracy of the cylinder inner / outer diameter due to resin sink during injection molding can be prevented.

Further, since the ferrule 4 is required to have high accuracy, it is mainly composed of metal or ceramics, but can be composed of resin. When the ferrule 4 is made of resin, the resin that forms the resin sleeve 1 is made of the same resin as the resin that forms the ferrule 4, so that the linear expansion coefficient is the same. It is possible to suppress the shaking of the fixing force and to stably prevent the common omission. Further, it is possible to suppress the occurrence of misalignment and angular misalignment of the optical fibers to be connected during use. Furthermore, it is more preferable that the orientation of the filler is matched between the resin sleeve 1 and the ferrule 4.

Since the sleeve is made of resin, it can be reduced in weight and cost compared to the case of ceramic. In particular, by providing a contact portion with a gate portion and an ejector pin on the flange and performing injection molding, the resin sleeve can be thinned, and further miniaturization (space saving) and weight reduction can be achieved. Further, even when the ferrule 4 as a mating partner is made of metal or ceramics, vibration and impact are not easily transmitted to the ferrule 4 by the resin sleeve 1, and the ferrule 4 itself or the optical fiber 5 inside thereof is damaged. Can be prevented.

FIG. 6 shows another example of a resin sleeve for an optical connector. 6A is a front view as seen from the end face side of the resin sleeve, and FIG. 6B is a cross-sectional view of FIG. 6A taken along line BB. FIG. 6C is a cross-sectional view of the resin sleeve after injection molding (before gate processing). The resin sleeve 11 has a cylindrical shape, and as shown in FIG. 6C, a gate portion 12 is provided on one cylindrical end surface 11a and is injection-molded using a resin. Thereafter, the cylindrical end surface 11a including the gate portion 12 is additionally machined by a method described later to make a surface without a convex portion in the axial direction, and a cylindrical resin sleeve 11 as shown in FIGS. 11 (a) and 11 (b). Is obtained. In the resin sleeve 11, at least the cylindrical end surface 11 a including the gate portion 12 may be additionally processed, and the opposite cylindrical end surface 11 b may be additionally processed. In the configuration in which the axial position of the ferrule tip is positioned in the axial length of the sleeve, high accuracy is required for the axial dimension of the sleeve, so it is preferable to additionally process both cylindrical end surfaces after molding. . In addition, the cylindrical sleeve shown in FIG. 6 can be provided with, for example, a common omission prevention structure A.

Here, the cylindrical end surface of the sleeve means “a surface having no convex portion with respect to the axial direction” means a substantially flat surface perpendicular to the axial direction of the sleeve, and the surface may have some concave portions. . For example, as shown in FIG. 7, the periphery where the gate portion 12 is provided may be a recess.

Further, as shown in FIG. 8, in the resin sleeve 11, it is preferable to form a flange 13 at at least one cylindrical end. By providing this flange 13, it can be used as the common omission prevention structure B, and it is easy to apply a pressing force to the sleeve end face when the ferrule is fitted. When the flange 13 is formed, the end face of the flange 13 becomes the cylindrical end face 11a provided with the gate portion.

The additional machining may be any machining method that can machine the cylindrical end faces 11a and 11b of the resin sleeve 11 with high accuracy, and is excellent in mass productivity and machining accuracy. Therefore, such as turning, cutting, grinding, and polishing. It is preferable to use machining. In particular, by using a lapping process as a grinding process and simultaneously processing a large number of resin sleeves, the width dimension of each sleeve can be made highly accurate.

Also, non-contact processing using water or laser can be adopted. In the case of non-contact processing, deformation of the resin sleeve during processing can be minimized, and stable dimensional accuracy can be ensured. In particular, laser processing can reduce the irradiation diameter, and more accurate processing is possible.

As in the case described with reference to FIG. 4, since the gate portion 12 in FIG. 6 and the like is provided on the cylindrical end surface 11a, the gate structure is a pinpoint gate / side gate. Moreover, in order to ensure the roundness of the resin sleeve 11, it is preferable to use multipoint gates arranged at predetermined intervals. The gate portion 12 is removed by the additional process. The trace of the gate portion 12 (gate trace) is also usually removed by the additional process. As shown in FIG. 7, when the gate portion 12 is provided, the gate mark 12a may remain even after the additional work, but in this case also, the gate mark 12a does not protrude from the cylindrical end surface 11a.

The resin material in the resin sleeve in the mode of performing additional machining is the same as described above. The optical connector joint portion of the optical connector member using the optical connector resin sleeve will be described with reference to FIG. FIG. 9 is a cross-sectional view showing the optical connector joint. As shown in FIG. 9, the resin sleeve 11 has a cylindrical inner surface 11 c fitted with the fitting portions 14 c of the pair of ferrules 14, and holds the pair of ferrules 14 while being coaxially butted. Yes. Further, the cylindrical end surfaces 11 a and 11 b of the resin sleeve 11 are in contact with the step surfaces 14 a and 14 b of the fitting portions 14 c of the respective ferrules 14. According to this aspect, the axial positioning of the ferrule tip in the resin sleeve 11 is performed. By holding the pair of ferrules 14 in a state of being coaxially abutted on the cylindrical inner surface 11c of the resin sleeve 11, the wire insertion holes 14d at the tip of the ferrule 14 are connected in a state of being coaxially aligned.

In this aspect, since the cylindrical end surfaces 11a and 11b that contact the stepped surfaces 14a and 14b of the fitting portion 14c of the ferrule 14 are additional surfaces, the dimensional accuracy in the axial direction of the sleeve is excellent, and the ferrule 14 in the resin sleeve 11 is excellent. Excellent position accuracy in the axial direction of the tip. As shown in FIG. 9, the tip of the ferrule 14 is in a state of being abutted with a slight gap, but with the above-described configuration, fluctuations in the gap width and the like can be suppressed. The loss of optical communication at the junction can be reduced.

Since the resin sleeve 11 of this aspect is injection-molded with the gate portion 12 provided on the cylindrical end surface 11a, it is possible to prevent the occurrence of gate marks and burrs on the cylindrical inner surface. In addition, the orientation of the filler contained in the resin becomes the axial direction, and a decrease in the dimensional accuracy of the inner and outer diameters of the sleeve cylinder due to resin sink during injection molding can be prevented.

Further, in the resin sleeve 11, as described above, since the orientation of the filler is in the axial direction, the gate position and the like are optimized when the ferrule 14 is manufactured, and the orientation of the filler in the fitting portion of the ferrule 14 is also axial. The direction is preferred. Thereby, the orientation of the filler can be matched between the resin sleeve 11 and the ferrule 14.

Hereinafter, the resin ferrule for optical connectors used for the optical connector member of the present invention will be described.

When connecting optical fiber cables, the cables hold the ferrules at the end of each cable fitted into the sleeves and hold them together, and the optical fiber strands that protrude from the cable sheath at the ferrule joint ends are coaxial. Connected with matching on top. In this configuration, in order to reduce optical communication loss due to axial misalignment or the like, it is necessary to reduce the coaxiality between the optical fiber strands (element insertion holes) at the joint. Therefore, also on the ferrule side, the outer diameter roundness of the fitting portion fitted into the sleeve, the coaxiality with respect to the outer diameter of the strand insertion hole for inserting the optical fiber strand, the inner diameter perfect circle of the strand insertion hole High dimensional accuracy is required for degrees and cylindricity.

Since the optical connector ferrule requires such high accuracy, it is mainly composed of metal, ceramics, or the like. For example, a ceramic product is used which is obtained by firing a molded product obtained by injection molding or compression molding using a mixed material of ceramic powder such as zirconia powder and a resin material, followed by polishing. In a ceramic ferrule, a processing method for processing an insertion hole of an optical fiber strand with high accuracy has been developed (Japanese Patent Laid-Open No. 5-113523).

In recent years, the use of optical fiber has been promoted in the automobile field due to an increase in the amount of data handled by car navigation systems and AV devices mounted on vehicles. Further, in the automobile field, energy saving is progressing, and a compact and lightweight structure is required as compared with a conventional communication connector for the purpose of reducing the weight. In response to such demands, development of resin ferrules has been promoted in order to reduce weight, mass production, and cost.

For example, as a resin ferrule that can be economically manufactured without abnormality in the outer diameter, a fitting surface that is detachably fitted to the sleeve, and formed on one end side of the fitting surface, than the fitting surface A stepped surface with a small diameter, an end surface facing the tip of the optical fiber, a tapered surface that tapers toward the end surface and continues to the stepped surface, and a strand insertion hole through which the optical fiber strand is inserted through the end surface And a ferrule having a core guide hole that communicates with the strand insertion hole and through which the optical fiber core is passed is proposed (Japanese Patent Laid-Open No. 2001-147343).

In addition, in order to increase the outer diameter dimensional accuracy and coaxiality of the resin ferrule, a ferrule having a resin insert hole formed on the outer periphery of the resin ferrule body with an insertion surface to the sleeve. Has been proposed (Japanese Patent Laid-Open No. 2001-96570).

In addition, in the insert pipe that forms the outer cylinder, a resin molding part that forms a fiber mounting hole in the shaft center is integrally provided, and a ferrule body that has a locking part on the outer periphery of the rear end of the insert pipe, and a ferrule body A fiber mounting hole that is continuous with the fiber insertion hole is formed at the center of the shaft, and is formed of a cylindrical base portion that is resin-molded on the rear end side of the ferrule body. This base portion covers the engaging portion of the insert pipe. There has been proposed a ferrule that is integrally joined to a resin molding portion of a ferrule body in an aspect (Japanese Patent Laid-Open No. 2004-38005).

However, when the ferrule is formed only from metal or ceramics, it is not easy to reduce the weight and cost. Since connector components are required at a rate of about one for every 20 m of optical fiber cable, weight reduction for each ferrule alone is an important issue when the optical fiber cable is loaded on a vehicle. By using ceramics having a specific gravity smaller than that of metal, the weight can be reduced as compared with the case of using metal. However, in order to finish the optical fiber insertion hole with high accuracy, for example, as disclosed in JP-A-5-113523 Difficult machining is required, and cost reduction is difficult.

On the other hand, resin ferrules cannot make the length of the wire insertion hole longer than ceramic ferrules such as zirconia. For this reason, the optical fiber strands in the strand insertion holes are greatly twisted, and the misalignment and angular misalignment of the optical fibers connected using the ferrule tend to be large.

Also, with resin ferrules, if the flow path during injection molding is long or the cavity shape is complicated, the flowability and filling amount of the resin may be non-uniform, and the dimensional accuracy may be due to resin sink marks. May decrease. For example, there is a possibility that the outer diameter roundness of the fitting portion fitted to the sleeve in the ferrule is inferior, or the inner peripheral surface of the optical fiber strand insertion hole is distorted.

In the technique disclosed in Japanese Patent Laid-Open No. 2001-147343, it is possible to improve the abnormality of the outer diameter of the ferrule joint end portion. However, in the fitting portion fitted to the sleeve, there is a portion where the resin thickness is not constant. For this reason, there is a possibility that the dimensional accuracy of the wire insertion hole is inferior due to the sink mark of the resin at the time of injection molding.

In addition, when using an insert pipe made of a hard material as in JP-A-2001-96570 and JP-A-2004-38005, it is disadvantageous in terms of weight reduction and cost reduction. In addition, since the mating surface with the sleeve is made of a hard material, in the case where the sleeve side is also made of ceramics, vibrations and impacts are likely to be transmitted to the optical fiber and may be damaged.

Because of these problems, even when the length of the strand insertion hole is such that the twist of the optical fiber strand can be sufficiently reduced in the resin ferrule, the outer diameter of the fitting portion and the optical fiber fitted into the sleeve It is desired to provide a resin ferrule for optical connectors that is excellent in dimensional accuracy of a wire insertion hole for inserting a wire and can reduce optical communication loss.

The resin ferrule for an optical connector of the present invention is fitted to a main body portion having a core wire insertion hole through which a core wire of an optical fiber is passed, and a sleeve having a strand insertion hole through which the strand of the optical fiber is passed. A resin ferrule for an optical connector comprising a joint portion, wherein the fitting portion having the wire insertion hole and the main body portion are integrally formed by resin injection molding, and the fitting portion is A cylindrical shape having the strand insertion hole as an axial center. Since the fitting part has a cylindrical shape centered on the element insertion hole, the thickness of the outer periphery (fitting part) of the element insertion hole is constant, and the element insertion hole due to resin sink marks during injection molding And the fall of the dimensional accuracy of a fitting part outer diameter can be prevented.

The ratio (Lin / D) between the axial length Lin and the hole diameter D of the wire insertion hole is 15 or more. In addition, the axial length Lout of the fitting portion is not less than the axial length Lin of the strand insertion hole. Since the ratio (Lin / D) between the axial length Lin and the hole diameter D of the strand insertion hole is 15 or more, the core of the optical fiber in which the strand insertion hole is secured long and is connected using the ferrule Deviation and angular deviation can be reduced, and the coaxiality of the optical fibers to be connected can be sufficiently reduced. Thus, it is possible to reduce optical communication loss when optical fibers are connected using the resin ferrules for optical connectors.

In the fitting portion, a cored bar is provided on the outer periphery of the strand insertion hole so as to be separated from the inner peripheral surface of the strand insertion hole. Further, the core bar is a cylindrical shape concentric with the wire insertion hole. Further, the core metal is made of stainless steel. In the fitting portion, a cored bar is provided on the outer periphery of the strand insertion hole so as to be separated from the inner peripheral surface of the strand insertion hole, so that the dimensional accuracy of the strand insertion hole due to resin sink at the time of injection molding is improved. Decline can be prevented.

In the fitting portion, a sleeve-like metal portion is formed on the inner peripheral surface of the wire insertion hole. The metal part is an electroformed part formed by electroforming. The electroformed part includes nickel (hereinafter referred to as Ni), copper (hereinafter referred to as Cu), palladium (hereinafter referred to as Pd), chromium (hereinafter referred to as Cr), and nickel-cobalt (hereinafter referred to as “Pd”). , Ni—Co), and at least one metal selected from an alloy is used as a plating substrate. Since the sleeve-shaped metal portion is formed on the inner peripheral surface of the strand insertion hole, it is possible to prevent a reduction in the dimensional accuracy of the strand insertion hole due to resin sink marks during injection molding. Further, by making the metal part an electroformed part formed by electroforming, the dimensional accuracy of the inner peripheral surface of the electroformed part that becomes an actual strand insertion hole is excellent.

In the main body portion, a sleeve-like metal portion is formed on the inner peripheral surface of the core wire insertion hole, and the core wire of the optical fiber is bonded and fixed on the metal portion. The metal part is made of stainless steel. In the main body portion, a sleeve-like metal portion is formed on the inner peripheral surface of the core wire insertion hole, and the core wire of the optical fiber is bonded and fixed at the metal portion. A reduction in the dimensional accuracy of the wire insertion hole can be prevented. In addition, by performing the bonding with the optical fiber core wire at the metal portion, the adhesive strength with the optical fiber core wire (in the coating) can be excellent, and the shift or disconnection of the core wire can be prevented.

The resin forming the ferrule is a liquid crystalline resin or a polyetherimide resin. Since the resin forming the ferrule is a liquid crystalline resin or a polyetherimide resin, it has excellent injection moldability, and the ratio (Lin / D) between the axial length Lin and the hole diameter D of the wire insertion hole is 15 or more. This resin ferrule can be molded while suppressing the occurrence of burrs. In addition, since it has excellent dimensional stability against temperature changes, it can be suitably used as a ferrule for an on-vehicle optical fiber cable used in a wide temperature range (about −40 ° C. to 90 ° C.).

The fitting portion of the sleeve with the fitting portion is made of resin, and the resin forming the ferrule is the same resin as the resin forming the fitting portion of the sleeve. Since the fitting part of the sleeve with the fitting part is made of resin and the resin forming the ferrule is the same resin as the resin forming the fitting part of the sleeve, the linear expansion coefficient is the same. Yes, it is possible to suppress the occurrence of misalignment and angular misalignment of the optical fibers to be connected during use.

An example of a resin ferrule for an optical connector will be described with reference to FIG. As shown in FIG. 10, the resin ferrule 21 includes a main body portion 23 having a core wire insertion hole 23a through which an optical fiber core wire 25 is passed, and a strand insertion hole 22a through which an optical fiber strand 24 is passed. The fitting part 22 which has this. The main body 23 has a hollow portion 23c on the outer diameter surface 23b, and is fixed to an optical connector member (not shown) by a spring or the like at this portion.

The fitting portion 22 includes a fitting surface 22b that is detachably fitted to a cylindrical sleeve (see FIG. 12), and an end surface 22c that is a butt surface where the tip of the optical fiber 24 is positioned. Have The fitting portion 22 has a cylindrical shape with the strand insertion hole 22a as an axis. Here, as shown in FIG. 10, the cylindrical shape with the strand insertion hole 22a as an axis is a cylindrical shape in which only the portion of the strand insertion hole 22a is removed from the columnar shape concentric with the strand insertion hole 22a. It is. By forming the fitting portion 22 in this shape, the thickness of the outer periphery of the strand insertion hole 22a becomes constant, and the strand insertion hole 22a and the fitting surface 22b of the fitting portion 22 due to resin sink during injection molding are formed. Decrease in dimensional accuracy can be prevented. Further, in order to facilitate the assembly of the ferrule and the sleeve, a C chamfering or an R chamfering may be provided at the corner between the fitting surface 22b and the end surface 22c within a range that does not deteriorate the accuracy of the strand insertion hole 22a. Good (see FIG. 1 etc.). When such chamfering is provided, the fitting portion 22 has a substantially cylindrical shape (a portion other than the chamfered portion is cylindrical). The “cylindrical shape” of the fitting portion 22 in this specification includes the substantially cylindrical shape as long as the accuracy of the strand insertion hole 22a is not deteriorated.

The axial length Lout of the fitting portion 22 is preferably the same as or longer than the axial length Lin of the strand insertion hole 22a. By doing so, the thickness of the outer periphery of the strand insertion hole 22a is constant throughout the axial direction, and the dimensional accuracy is reduced due to resin sink marks during the injection molding over the entire axial direction of the strand insertion hole 22a. Can be prevented. Particularly preferably, the axial length Lout of the fitting portion 22 is the same as the axial length Lin of the strand insertion hole 22a. By doing so, the thickness of the fitting portion 22 is constant throughout the axial direction, and the resin sink marks during the injection molding over the entire axial direction of the strand insertion hole 22a and the fitting surface 22b of the fitting portion 22 are fixed. It is possible to prevent a decrease in dimensional accuracy due to

In the resin ferrule 21, it is preferable that the ratio (Lin / D) between the axial length Lin and the hole diameter D of the wire insertion hole 22a in the fitting portion 22 is 15 or more. More preferably, Lin / D is 30 or more. By setting Lin / D to 15 or more, the strand insertion hole 22a is secured long, and the optical fiber strand 24 in the strand insertion hole 22a is less twisted (see FIG. 11A). As a result, misalignment and angular misalignment between optical fibers connected using the ferrule can be reduced, and the coaxiality between optical fibers can be sufficiently reduced. On the other hand, if the length of the strand insertion hole is short as in the conventional resin ferrule, the optical fiber strand in the strand insertion hole becomes large (see FIG. 11B).

The optical connector joint portion of the optical connector member using the resin ferrule for optical connectors in this aspect will be described with reference to FIG. FIG. 12 is a cross-sectional view showing the optical connector joint. The resin ferrule 21 in FIG. 12 has the same axial length of the fitting portion 22 and the axial length of the strand insertion hole 22a. As shown in FIG. 12, a pair of resin ferrules 21 are held in a state where the fitting portions 22 are fitted and butted against a cylindrical sleeve 26, and a strand insertion hole 22 c is formed on the joining end surface 22 c of the resin ferrule 21. The connection is made in a state where 22a is coaxially matched. Examples of the sleeve 26 to be used include the above-described resin sleeve for optical connectors of the present invention.

In each resin ferrule 21, the strand insertion hole 22 a is long and the optical fiber strand 24 in the strand insertion hole 22 a is less twisted. At the same time, the length of the fitting surface 22 b of the fitting portion 22 is also reduced. Since it is secured for a long time, it is easy to keep the coaxiality of the ferrules small when fitted and held in the sleeve 26. In addition, since the dimensional accuracy of the strand insertion hole 22a and the fitting surface 22b of the fitting portion 22 is also excellent, the misalignment and angular deviation of the optical fibers to be connected are small, and the coaxiality between the optical fibers is sufficient. The optical communication loss at the joint can be reduced. Further, since the fitting surface 22b of the fitting portion 22 of the resin ferrule 21 is a resin surface, even when the sleeve 26 which is the mating partner is made of ceramics, vibration and impact are generated in the strand insertion hole 22a. It is difficult to be transmitted to the optical fiber 24 and damage can be prevented.

Another example of a resin ferrule for an optical connector will be described with reference to FIG. FIG. 13 is a cross-sectional view showing a resin ferrule for an optical connector having a cored bar. As shown in FIG. 13, the resin ferrule 21 of this aspect has a metal core 27 provided on the outer periphery of the strand insertion hole 22 a in the fitting portion 22 so as to be separated from the inner peripheral surface of the strand insertion hole 22 a. Become. In addition, it is set as the position which does not protrude to the fitting surface 22b. The core metal 27 is arranged in the fitting portion 22 by being placed at a predetermined position in the injection mold and insert-molded when the resin ferrule 21 is injection molded. As shown in FIG. 13, by providing the cored bar 27, it is possible to prevent a decrease in dimensional accuracy of the wire insertion hole 22a due to resin sink marks during injection molding.

The cored bar 27 has substantially the same axial length as the strand insertion hole 22a, and may be disposed in parallel with the strand insertion hole 22a. In order to make the wall thickness on the inner peripheral surface side of the strand insertion hole 22a uniform, it is particularly preferable to use a cylindrical shape (pipe shape) concentric with the strand insertion hole 22a. The thickness of the core metal 27 is preferably reduced within a range that does not deform during injection molding in order to reduce the weight of the entire ferrule. Further, by providing a through hole in a part of the core metal 27 and performing injection molding (insert molding), it is possible to prevent misalignment of the core metal 27 and the like.

The material of the metal core 27 can be any material such as brass or stainless steel, but is preferably made of stainless steel. By being made of stainless steel, it is excellent in rust prevention and mechanical strength, and has a relatively close thermal expansion coefficient to that of a liquid crystal resin or the like forming a ferrule, so that the fitting surface 22b of the fitting portion 22 and the strand insertion hole 22a Less affected by dimensional accuracy.

Another example of a resin ferrule for an optical connector will be described with reference to FIG. FIG. 14 is a cross-sectional view showing a resin ferrule for an optical connector having a sleeve-like metal portion on the inner peripheral surface of the strand insertion hole. As shown in FIG. 14, the resin ferrule 21 of this aspect is formed by forming a sleeve-like metal portion 28 on the inner peripheral surface of the strand insertion hole 22a. As the metal part 28, the thing which consists of a cylindrical metal pipe similarly to the said metal core, the thing formed by electroforming, etc. can be used. It is preferable that the metal portion 28 is an electroformed portion formed by electroforming because the dimensional accuracy of the inner peripheral surface of the electroformed portion that becomes an actual wire insertion hole is excellent.

As a method for forming an electroformed part by electroforming, a known method can be adopted. For example, a master shaft made of stainless steel or the like having the same diameter as the wire insertion hole is prepared, and an electroformed portion that becomes the metal portion 28 is formed by electroplating the outer periphery of the master shaft. The entire ferrule is formed by placing the master shaft having the electroformed portion at a predetermined position in the injection mold and insert molding. Thereafter, by pulling out only the master shaft, a resin ferrule having a metal part (electroformed part) on the sleeve formed on the inner peripheral surface of the strand insertion hole is obtained. In addition, since the inner peripheral surface of the strand insertion hole is determined by the outer peripheral surface of the master shaft, the outer peripheral surface of the master shaft has high surface accuracy such as roundness, cylindricity, and surface roughness in advance. It is necessary to finish it.

As the plating substrate, Ni, Cu, Pd, Cr, and a Ni—Co alloy are preferably employed because the thermal expansion coefficient is relatively close to that of the liquid crystal resin forming the ferrule. In addition to the electroplating described above, an electroless plating method in which metal is deposited by the action of a reducing agent added to an aqueous metal salt solution without using electricity may be employed.

Another example of a resin ferrule for an optical connector will be described with reference to FIG. FIG. 15 is a cross-sectional view showing a resin ferrule for an optical connector having a sleeve-like metal portion on the inner peripheral surface of the core wire insertion hole. As shown in FIG. 15, the resin ferrule 21 of this aspect has a main body portion 23 in which a sleeve-like metal portion 29 is formed on the inner peripheral surface of the core wire insertion hole 23 a. As the metal part 29, the thing which consists of a cylindrical-shaped metal pipe etc. can be used similarly to the said metal core. The metal part 29 is arranged in the main body part 23 by inserting a metal pipe or the like prepared in advance into a predetermined position in the injection mold when the resin ferrule 21 is injection-molded. The

The material and shape of the metal part 29 are preferably the same as those of the core metal. That is, the material is excellent in rust prevention and mechanical strength, and has a relatively close thermal expansion coefficient to the liquid crystal resin forming the ferrule, etc., and hardly affects the dimensional accuracy of the core wire insertion hole 23a of the main body 23. Therefore, it is preferable to use stainless steel.

As shown in FIG. 15, by providing the metal part 29, it is possible to prevent a decrease in the dimensional accuracy of the core wire insertion hole 23a due to resin sink during injection molding. In addition, since the metal portion 29 is bonded to the optical fiber core wire 25, the metal portion 29 is not provided, and the metal portion 29 is not directly bonded to the inner peripheral surface (resin) of the core wire insertion hole. The adhesive strength with the optical fiber core 25 (coating) is excellent, and the optical fiber core 25 can be prevented from shifting or coming off.

The modes described with reference to FIGS. 13 to 15 may be a mode in which some or all of these modes are combined.

The main body portion 23 and the fitting portion 22 in the resin ferrule 21 are integrally formed by resin injection molding. In the injection molding, a core pin for forming a wire insertion hole 22a is arranged in an injection mold, and the entire ferrule including the fitting 22 having the wire insertion hole 22a and the main body portion 23 is integrally injection-molded. . Therefore, the strand insertion hole 22a is different from a hole formed by post-processing or the like, and the inner peripheral surface of the strand insertion hole 22a is a molding surface. By making the thickness of the outer periphery of the strand insertion hole 22a constant as described above, or using a cored bar or the like, the inner peripheral surface of the strand insertion hole 22a is a molding surface. Decline can be prevented.

As the resin material, known resins used for resin ferrules can be used. A resin excellent in injection moldability that hardly generates burrs or the like is preferable. Specifically, the same resin and filler as the above-described resin sleeve can be used, and it is preferable to use a liquid crystal resin or a polyetherimide resin.

When the strand insertion hole has an elongated shape (for example, Lin / D is 15 or more) as described above, the core pin that forms the strand insertion hole is elongated in the injection mold. Since the liquid crystal resin exhibits liquid crystallinity in a molten state, it has good fluidity at the time of molding, and it becomes easy to prevent the core pin from being displaced at the time of injection molding. Also, when a core metal as shown in FIG. 13 is placed in an injection mold and injection molded, the resin is sufficiently filled to the end.

The resin sleeve of the present invention has a simple structure that does not require a sleeve holder, and can prevent the ferrule and the sleeve from slipping out while reducing the size, weight, and cost, so that the end of the optical fiber cable can be prevented. It can be used as a sleeve for connecting optical ferrules provided in the section. For this reason, it can utilize suitably as a sleeve of the optical fiber cable for vehicle mounting in which weight reduction and size reduction (space saving) are required.

DESCRIPTION OF SYMBOLS 1 Resin sleeve 1a The part by which a ferrule is fitted and hold | maintained 1b The part by which the ferrule which is an extraction side is fitted and held 2 Flange 2a End surface of a flange (the axial direction opposite side of 2b)
2b Flange end face 2c Flange outer diameter face 3 Housing 3a Engagement part 4 Ferrule 4a Fitting part 4b Element insertion hole 5 Optical fiber element 6 Optical fiber core wire 7 Gate part 8 Ejector pin 11 Resin sleeve 11a Cylindrical end face 11b Cylindrical end surface 11c Cylindrical inner surface 12 Gate portion 12a Gate mark 13 Flange 14 Ferrule 14a Step surface 14b Step surface 14c Fitting portion 14d Strand insertion hole 15 Optical fiber strand 16 Optical fiber core wire 21 Plastic ferrule 22 Fitting portion 23 Main body 24 Optical fiber 25 Optical fiber core 26 Sleeve 27 Core 28 Metal part (provided on the inner peripheral surface of the wire insertion hole)
29 Metal part (provided on the inner peripheral surface of the core wire insertion hole)

Claims (18)

A cylindrical resin sleeve for an optical connector for holding two ferrules provided at the end of an optical fiber cable in a coaxial manner,
The resin sleeve has a joint slip prevention structure in which the resin sleeve is fixed to the other ferrule side when the one ferrule is pulled out from the state where the two ferrules are held.
In the joint slip prevention structure, (1) in the resin sleeve, the cylindrical thickness of the portion where the other ferrule is fitted and held is thicker than the cylindrical thickness of the portion where the one ferrule is fitted and held. Structure A and (2) a flange formed on one cylindrical end of the resin sleeve, and an optical connector member housing that engages with the flange and fixes the resin sleeve to the other ferrule side A resin-made sleeve for an optical connector, wherein the sleeve is at least one structure selected from the structure B consisting of the engagement portion in FIG. The resin sleeve has the structure A, and in the structure A, a cylindrical inner diameter of the resin sleeve or a cylindrical outer diameter of the resin sleeve is constant in an axial direction. Item 11. A resin sleeve for an optical connector according to Item 1. The resin sleeve has the structure B, and in the structure B, the engaging portion of the housing is in contact with the end surface on the opposite side in the axial direction of the end surface of the flange that is the cylindrical end surface of the resin sleeve. The resin sleeve for an optical connector according to claim 1. 2. The resin sleeve for an optical connector according to claim 1, wherein the resin sleeve has the structure B and is injection-molded by providing a gate portion on the flange. The gate portion is provided on an outer diameter surface of the flange, an end surface of the flange serving as a cylindrical end surface of the resin sleeve, or an end surface of the flange opposite to the end surface in the axial direction. The resin sleeve for optical connectors according to claim 4. 5. The resin sleeve for an optical connector according to claim 4, wherein the resin sleeve has a contact portion with an ejector pin at the time of injection molding on the flange. The said resin sleeve has the said contact part in the end surface of the said flange used as the cylindrical end surface of this resin sleeve, or the end surface of the said flange on the opposite side to the axial direction of this end surface. Resin sleeve for optical connectors. The resin sleeve is provided with a gate portion on one cylindrical end surface and is injection-molded using a resin, and then a cylinder end surface including at least the gate portion is additionally machined to have a surface having no convex portion with respect to the axial direction. And
In the resin sleeve, the fitting portions of the two ferrules are fitted to the inner diameter surface of the cylinder, respectively, and contact with the ferrules at the cylindrical end surfaces, and the axial direction of the tip end portion of the ferrule in the sleeve 2. The resin sleeve for an optical connector according to claim 1, wherein positioning is performed. The resin sleeve for an optical connector according to claim 8, wherein the gate portion is removed by the additional work in the resin sleeve. The resin sleeve for an optical connector according to claim 8, wherein the additional machining is machining. The resin sleeve for an optical connector according to claim 10, wherein the machining is grinding. The resin sleeve for an optical connector according to claim 11, wherein the grinding is lapping. The resin sleeve for an optical connector according to claim 8, wherein the additional processing is non-contact processing. 14. The resin sleeve for an optical connector according to claim 13, wherein the non-contact processing is laser processing. The resin sleeve for an optical connector according to claim 1, wherein the resin forming the resin sleeve is a liquid crystalline resin or a polyetherimide resin. The resin sleeve for an optical connector according to claim 1, wherein the ferrule is made of a resin, and the resin forming the resin sleeve is the same resin as the resin forming the ferrule. In the resin sleeve, a frictional force between a cylindrical inner surface of a portion where the one ferrule is fitted and held and a fitting surface of the ferrule is a cylindrical inner surface of a portion where the other ferrule is fitted and held. 2. The resin sleeve for an optical connector according to claim 1, wherein the sleeve is smaller than a frictional force with a fitting surface of the ferrule. An optical connector member comprising a housing, two ferrules provided at the ends of different optical fiber cables, and a cylindrical sleeve for fitting and holding these ferrules coaxially on the cylindrical inner surface. ,
The optical sleeve according to claim 1, wherein the sleeve is a resin sleeve for an optical connector.

Images