JP5250387B2 - Ferrule - Google Patents

Description

  The present invention relates to a ferrule used when optically coupling an optical fiber and an optical device or optically coupling optical fibers.

The receptacle type optical connector mounted on the circuit board is fitted with a plug type optical connector provided at the end of the optical fiber cable so that optical coupling is achieved. A plug-type optical connector is usually structured to pull out an optical fiber cable straight. However, for example, because of space limitations, the optical fiber cable may be bent and pulled out in a direction substantially perpendicular to the fitting direction of the optical connectors. Exists (for example, see Patent Documents 1 and 2 below). Since an optical fiber composed of a core and a clad is vulnerable to extreme bending, an optical connector for bending and pulling out an optical fiber cable is provided with a structure for preventing excessive bending.
Japanese Patent Laid-Open No. 10-78534 JP 2001-51151 A

  The optical connector disclosed in Patent Literature 1 has a spring cap (named in the literature is a ferrule holder) disposed behind the ferrule as a component constituting the optical connector. The spring cap is adapted to be fitted to the rear portion of the optical connector housing that houses the ferrule. The spring cap has a cylindrical portion that extends rearward and through which the optical fiber cable is inserted. Since the optical connector disclosed in Patent Document 1 has a cylindrical portion, the bending start position becomes the cylindrical portion tip position when the optical fiber cable is bent and pulled out. Therefore, when the optical connector is viewed at a distance (length) between the ferrule tip or the optical connector housing tip and the bending end position of the optical fiber cable, the size of the optical connector is large.

  On the other hand, the optical connector disclosed in Patent Document 2 is also provided with a spring cap. The spring cap is integrally formed with a structure for preventing excessive bending of the optical fiber cable. Each part of the spring cap is devised. When the optical fiber cable is bent and pulled out, the bending start position is the rear end face position of the ferrule. Therefore, the optical connector disclosed in Patent Document 2 is more compact in size than the optical connector disclosed in Patent Document 1.

  By the way, the minimum bending radius of the optical fiber cable is determined, and the length required for fitting to the receptacle type optical connector is also limited, so that the conventional plug type optical connector is further miniaturized. It has the problem that it is difficult.

  This invention is made | formed in view of an above-described situation, and makes it a subject to provide the ferrule which has an effective structure for size reduction of an optical connector.

In order to solve the above-mentioned problems, the ferrule of the present invention according to claim 1 includes an optical connector housing 4 that fits into a receptacle-type optical connector, and the front and rear surfaces of the optical connector housing 4 are open at the front and rear surfaces. A pair of ferrule housing chambers 8 is formed, a protrusion 9 and a wall 10 are formed on the rear surface of the optical connector housing 4, and an overbending prevention housing 6 for preventing excessive bending of the optical fiber cable 2 is provided, The optical fiber cable 2 is housed in the ferrule housing chamber 8 of the optical connector 1 configured to bend in a direction substantially perpendicular to the fitting direction of the optical connectors,
An optical fiber cable 2 configured to include an optical fiber 11 composed of a core and a clad and a jacket 12 provided outside the optical fiber 11 is stripped of the optical fiber 11 by removing the jacket 12 to a predetermined length. In this state, an optical fiber insertion hole 14 for inserting the optical fiber 11 of the optical fiber cable 2 is formed on the front side, and the optical fiber cable 2 has the rear of the optical fiber insertion hole 14 behind the optical fiber insertion hole 14. A ferrule 3 in which a jacket insertion hole 15 for inserting the jacket 12 provided outside the optical fiber 11 is formed,
The jacket insertion hole 15 of the ferrule 3 is penetrated to the rear end surface 17 of the ferrule, and is formed in accordance with the diameter of the jacket 12.
The jacket insertion hole 15 of the ferrule 3 is formed with a taper portion 18 that gradually widens and is longer than the diameter of the jacket 12 at the rear end surface 17 of the ferrule and opens at least in the cable bending direction .
The length from the position where the taper portion 18 starts to be inclined to the ferrule rear end surface 17 is set to be about three times or more the length of the optical fiber guide portion 16;
The optical fiber cable 2 protruding from the opening of the tapered portion 17 is arranged so that bending starts from the inclination start position P of the tapered portion 18 and the jacket 12 does not adhere within the tapered portion 18. ,
The optical connector 1 is characterized in that a bending start position 2 b of the optical fiber cable 2 is set inside the ferrule 3 .

  According to the present invention having such a feature, the bending start position of the optical fiber cable is positioned inside the ferrule by the length of the tapered portion. If the bending start position moves, it will contribute to the miniaturization of the optical connector.

  A ferrule according to a second aspect of the present invention is the ferrule according to the first aspect, wherein the tapered portion is formed in a funnel shape.

  According to the present invention having such characteristics, the shape is such that there is a taper over the entire circumference. Thereby, it is not necessary to assemble a ferrule in accordance with the bending direction of the optical fiber cable, and as a result, it contributes to improvement in workability.

  According to the first aspect of the present invention, the ferrule can have a structure effective for miniaturization of the optical connector. By reducing the size of the optical connector, not only the material can be reduced, but also the weight can be reduced. If the weight is reduced as an in-vehicle optical connector, fuel efficiency can be improved.

  According to the second aspect of the present invention, since the tapered portion has a shape irrelevant to the directionality, it can contribute to the downsizing of the optical connector and also contributes to the improvement of the assembly workability. can do.

  Hereinafter, description will be given with reference to the drawings. FIG. 1 is a cross-sectional view of an optical connector showing an embodiment of the present invention. FIG. 2 is an enlarged cross-sectional view showing the tapered portion of the ferrule and the bending start position of the optical fiber cable.

  In FIG. 1, reference numeral 1 indicates a plug-type optical connector. The optical connector 1 is configured so that a pair of optical fiber cables 2 can be bent out. The optical connector 1 includes a ferrule 3 provided at the end of each optical fiber cable 2, an optical connector housing 4 that accommodates each ferrule 3 and fits into a receptacle-type optical connector (not shown), and an intermediate between the optical connector housing 4. The over-bending prevention which fits the rear part of the optical connector housing 4 which has the structure for preventing excessive bending with respect to each optical fiber cable 2 and the spacer 5 which fits to each ferrule 3 by fitting The housing 6 and a soft cover 7 provided so as to cover the overbending prevention housing 6 are configured.

  A pair of ferrule housing chambers 8 is formed in the optical connector housing 4 so that the front and rear surfaces are open. The overbending prevention housing 6 is formed with a protrusion 9 and a wall 10 for preventing the optical fiber cable 2 from being excessively bent. The optical fiber cable 2 is bent in a direction substantially perpendicular to the fitting direction of the optical connectors (quotation mark 2a indicates a bending end position). The optical fiber cable 2 is drawn from the end of the cover 7.

  The optical fiber cable 2 includes an optical fiber 11 composed of a core and a clad, and a jacket 12 provided outside the optical fiber 11 (the configuration is an example). At the end of the optical fiber cable 2, the jacket 12 is removed to a predetermined length, and the optical fiber 11 is exposed. The end face of the optical fiber 11 is exposed at the tip end face of the ferrule 3 (the end face of the optical fiber 11 does not protrude from the ferrule housing chamber 8).

  The ferrule 3 is formed in a substantially cylindrical shape. The ferrule 3 has two annular flange portions 13 on the outer peripheral surface. A locking portion of the spacer 5 is caught between the two flange portions 13. The ferrule 3 has an insertion hole that penetrates along the central axis. Specifically, it has an optical fiber insertion hole 14 and a jacket insertion hole 15.

  The optical fiber insertion hole 14 is formed on the front side of the ferrule 3 so that the optical fiber 11 can be inserted. The optical fiber insertion hole 14 is formed according to the diameter of the optical fiber 11.

  The jacket insertion hole 15 is formed behind the optical fiber insertion hole 14 so that the jacket 12 can be inserted therethrough. The jacket insertion hole 15 is formed according to the diameter of the jacket 12. The jacket insertion hole 15 is formed with a larger diameter than the optical fiber insertion hole 14.

  An optical fiber guide portion 16 is formed at a continuous position between the optical fiber insertion hole 14 and the jacket insertion hole 15. The optical fiber guide portion 16 is formed as a portion for smoothly guiding the optical fiber 11 passing through the jacket insertion hole 15 to the optical fiber insertion hole 14. The optical fiber guide portion 16 is also formed as a portion where the adhesive applied to the optical fiber 11 accumulates and hardens to increase the fixing force.

  The jacket insertion hole 15 is formed so as to penetrate to the ferrule rear end surface 17. The jacket insertion hole 15 is formed with a taper portion 18 that gradually widens and opens to the rear end face 17 of the ferrule. The taper portion 18 is a characteristic portion of the present invention, and is formed on the ferrule rear end surface 17 so as to be longer than the diameter of the jacket 12 and at least open in the cable bending direction. In the present embodiment, the tapered portion 18 is formed in a funnel shape.

The length from the position P (see FIG. 2) where the inclination of the taper portion 18 starts to the ferrule rear end face 17 (the length indicated by the dimension H in FIG. 2) is relatively long. In this embodiment, the optical fiber guide portion 16 It is set to be about 3 times or more of the length. The inclination of the taper portion 18 is set to be gentle. It is assumed that there is no adhesion with the jacket 12 in the tapered portion 18 .

  As shown in FIG. 1, when the optical connector 1 is assembled in such a shape that the optical fiber cable 2 is bent and pulled out, the optical fiber cable 2 starts to bend from the inside of the ferrule 3. Specifically, as shown in FIG. 2, the bending of the optical fiber cable 2 starts from the inclination start position P of the tapered portion 18 in the ferrule 3 (the bending starts at least within the range of the tapered portion 18). (Reference numeral 2b in the figure indicates the bending start position).

  In Patent Document 2 cited in the background art section, the bending start position is the rear end face position of the ferrule. However, when the ferrule 3 of the present invention is used, the dimension H corresponding to the length of the tapered portion 18 is obtained. Only the bending start position 2b can be moved in a direction advantageous for downsizing of the optical connector 1. As can be seen from the above description, the optical connector 1 is smaller than the conventional example.

  Up to this point, the ferrule 3 has been described as a feature. However, when the optical connector 1 is characterized, “the optical connector 1 sets the bending start position 2b of the optical fiber cable 2 inside the ferrule 3”. ing.

  It goes without saying that the present invention can be variously modified without departing from the spirit of the present invention.

It is sectional drawing of the optical connector which shows one embodiment of this invention. It is an expanded sectional view which shows the taper part of a ferrule and the bending start position of an optical fiber cable.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Optical connector 2 Optical fiber cable 2a Bending end position 2b Bending start position 3 Ferrule 4 Optical connector housing 5 Spacer 6 Overbending prevention housing 7 Cover 8 Ferrule accommodation chamber 9 Protrusion 10 Wall 11 Optical fiber 12 Jacket 13 Flange part 14 Optical fiber insertion Hole 15 Jacket insertion hole 16 Optical fiber guide part 17 Ferrule rear end face 18 Tapered part

Claims (2)

An optical connector housing 4 that fits into a receptacle-type optical connector is provided, and a pair of ferrule housing chambers 8 are formed on the front surface of the optical connector housing 4 so that the front surface and the rear surface are open. A protrusion 9 and a wall 10 are formed, and an overbending prevention housing 6 is provided for preventing the optical fiber cable 2 from being excessively bent. The optical fiber cable 2 is arranged in a direction substantially perpendicular to the fitting direction of the optical connectors. Accommodated in the ferrule housing chamber 8 of the optical connector 1 adapted to bend,
An optical fiber cable 2 configured to include an optical fiber 11 composed of a core and a clad and a jacket 12 provided outside the optical fiber 11 is stripped of the optical fiber 11 by removing the jacket 12 to a predetermined length. In this state, an optical fiber insertion hole 14 for inserting the optical fiber 11 of the optical fiber cable 2 is formed on the front side, and the optical fiber cable 2 has the rear of the optical fiber insertion hole 14 behind the optical fiber insertion hole 14. A ferrule 3 in which a jacket insertion hole 15 for inserting the jacket 12 provided outside the optical fiber 11 is formed,
The jacket insertion hole 15 of the ferrule 3 is penetrated to the rear end surface 17 of the ferrule, and is formed in accordance with the diameter of the jacket 12.
The jacket insertion hole 15 of the ferrule 3 is formed with a taper portion 18 that gradually widens and is longer than the diameter of the jacket 12 at the rear end surface 17 of the ferrule and opens at least in the cable bending direction .
The length from the position where the taper portion 18 starts to be inclined to the ferrule rear end surface 17 is set to be about three times or more the length of the optical fiber guide portion 16;
The optical fiber cable 2 protruding from the opening of the tapered portion 17 is arranged so that bending starts from the inclination start position P of the tapered portion 18 and the jacket 12 does not adhere within the tapered portion 18. ,
The ferrule, wherein the optical connector 1 sets a bending start position 2b of the optical fiber cable 2 inside the ferrule 3 . In the ferrule 3 according to claim 1,
The ferrule, wherein the tapered portion 18 is formed in a funnel shape.

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