JPH10213720A - Ferrule with metal fittings - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate the need for the severeness of size tolerance and to lower the cost by deforming a wall surface in the ferrule pressed-in recessed part of a metal holder by a groove formed in the wall surface when the ferrule is pressed in and bringing it contact with the outer peripheral surface of the ferrule. SOLUTION: A holding member 20 is made of a metallic material such as stainless steel, brass, and various allows and has a fiber insertion hole in the center and the ferrule pressed-in recessed part (pressed-in recess part) 22 at one end. The pressed-in recessed part 22 has many grooves of depth (s) in the wall surface and the wall surface plastically deforms when the ferrule 10 is pressed in to come into contact with the outer peripheral surface of the ferrule 10. Therefore, even when the external diameter d1 of the ferrule 10 is large and much larger than the internal diameter d2 of the pressed-in recessed part 22, the wall surface plastically deforms and absorbs the difference, so the ferrule is easily assembled and the outer peripheral surface of the metal holder 20 is prevented from swelling outward.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ferrule with metal fittings in which a ferrule for an optical connector used for connecting optical fibers to each other or an optical fiber and a photoelectric conversion element is fixed by a holding metal fitting.

[0002]

2. Description of the Related Art In a general optical connector, as shown in FIG. 9, a ferrule 10 made of ceramics such as zirconia and having a through hole 11 in the center is used. It is press-fitted into a ferrule press-fitting recess 22 provided in a metal holding fitting 20 having a fiber insertion hole 21 and is fixed.

After the optical fiber 30 is fixed to the ferrule 10, the optical fiber 30 and the adhesive are inserted into the fiber insertion hole 21 from the side opposite to the ferrule 10 in the holding metal fitting 20 and adhered. 30 removes the coating at the tip to expose the core 31, fits the core 31 into the through hole 11 of the ferrule 10, and furthermore, the coating 32 is held in the fiber insertion hole 21 of the holding member 20. Become.

[0004] When an optical connector is constructed, the ferrule 10 and the holding bracket 20 are mounted in a housing (not shown), and a front end face is formed between the ferrule 10 and another ferrule (not shown) similarly constructed. Optical signals can be transmitted between the two optical fibers by abutting the optical fibers 13 with each other.

When an optical module is configured, the ferrule 10 is provided in a package having a photoelectric conversion device.
, A light signal can be transmitted to the photoelectric conversion element.

In the conventional ferrule holding bracket 20, the press-fit recess 22 has a blind hole shape, and strict dimensional accuracy is required for the inner diameter of the press-fit recess 22 and the outer diameter of the ferrule 10. That is, when the inner diameter of the press-fit recess 22 is almost the same as or larger than the outer diameter of the ferrule 10, the ferrule 10 cannot be firmly supported and fixed. However, there is a risk that the fiber may break out of the holding bracket 20 and break the fiber. On the other hand, the press-fit recess 2
If the inner diameter of the ferrule 10 is too small with respect to the outer diameter of the ferrule 10, the ferrule and its fiber insertion hole 21 are tightened even if the ferrule 10 can be press-fitted. It is.

In this regard, since the ferrule 10 is made of a ceramic sintered body, it is relatively easy to increase the dimensional accuracy, and the ferrule 10 is actually manufactured with high accuracy. 0.002-0.
A tight tolerance of about 020 mm has been required.

[0008]

However, in practice, it is very difficult to process a metal part with a tolerance of about 0.002 to 0.020 mm and to produce it stably.
Attempting to meet the above tolerances has resulted in high cost parts.

In addition, when the holding fitting which does not satisfy the dimensional tolerance is used, as described above, the force for holding the ferrule is insufficient, and the ferrule cannot be firmly supported and fixed, or the assembly cannot be performed. In other words, the ferrule and its fiber insertion hole are tightened even if press-fitting is performed, and there is a problem that the fiber cannot be inserted.

[0010]

According to the present invention, a number of grooves or projections are formed in a ferrule press-fitting recess of a holding fitting for supporting and fixing a ferrule.

[0011]

According to the ferrule with the metal fitting of the present invention, the wall is plastically deformed when the ferrule is press-fitted by the groove provided on the wall inside the ferrule press-fitting concave portion of the holding metal, so that the ferrule comes into close contact with the outer peripheral surface of the ferrule. Therefore, the power to hold the ferrule is large,
Further, even if the outer diameter of the ferrule is considerably larger than the inner diameter of the ferrule press-fitting concave portion, the wall surface is plastically deformed and absorbs that amount, so that assembly is possible and the outer periphery of the metal fitting is prevented from expanding outward.

[0012]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a ferrule 1 with metal fittings of the present invention. The ferrule 1 with metal fittings has a ferrule 10 fixed to a holding metal fitting, and is mounted on an optical connector by mounting an optical fiber (not shown). is there.

The ferrule 10 is made of ceramics such as zirconia and has a cylindrical shape having a through hole 11 for inserting and fixing an optical fiber in the central axis direction. The outer periphery of 12 is a tapered tapered surface 14. In addition, the through hole 11
The fiber insertion port 11a on the side of the end 12 has a cone shape whose diameter gradually increases toward the end face, and has a shape such that an optical fiber can be easily inserted.

On the other hand, the holding member 20 is made of stainless steel / brass,
It is made of a metal material such as various alloys, has a fiber insertion hole 21 in the center, and has a ferrule press-fitting concave portion (hereinafter abbreviated as a press-fitting concave portion) 22 at one end. As shown in FIG.
A large number of grooves 24 having a depth s are formed in the ferrule 10, and as shown in FIG. 3, when the ferrule 10 is press-fitted, the wall surface 23 is plastically deformed and adheres to the outer peripheral surface 15 of the ferrule 10. Therefore, the force holding the ferrule 10 is large, and
As shown in FIG. 4, even if the outer diameter d1 of the ferrule 10 is considerably larger than the inner diameter d2 of the press-fit recess 22, the wall 23 is plastically deformed as described above and absorbs the amount (see FIG. 3). 3.) It is possible to assemble and prevent the outer peripheral surface 25 of the holding fitting 20 from expanding outward.

In the holding bracket 20, in order to sufficiently exhibit the above-described functions and effects, the depth s of the groove 24,
It is preferable that the pitch p and the angle θ are within the following numerical ranges. (See FIG. 2) Depth s: 0.005 to 0.600 mm Pitch: 0.020 to 1.000 mm Angle θ: 30 to 150 ° The reason why this numerical range is preferable is that If the depth s is smaller than 0.005 mm, there is almost no difference from the case without the groove. If the depth s is larger than 0.600 mm, the ferrule 1
If the pitch p is smaller than 0.020 mm, there is almost no difference from the case without the groove. If the pitch p is larger than 1.000 mm, the force for holding the ferrule 10 becomes insufficient. If the angle θ is less than 30 °, groove machining becomes difficult (the tool angle cannot be followed). If the angle θ is less than 30 °, when press-fitting,
There is a risk that the plastic deformation of the groove may be hindered. If the angle θ is larger than 150 °, the force of the plastic deformation that occurs at the time of press-fitting increases, and it is almost the same as the case without the groove.

Further, in the above ferrule with metal fitting 1,
It is desirable to satisfy the following relational expressions in order to sufficiently achieve the above-described functions and effects. (See FIG. 4) 0.12 s ≦ (d2−d1) ≦ 1.08 s where s is the depth of the groove 24 formed in the wall surface 23 of the press-fit recess 22 d1 is the outer diameter of the ferrule 10 d2 is the press-fit recess 22 That is, the inner diameter d2 of the press-fit recess 22 and the ferrule 1
When the difference (d2-d1) in the outer diameter of 0 is less than 0.12 times the depth s of the groove 24 formed in the wall surface 23 of the press-fit recess 22, the contact area between the ferrule 10 and the wall surface 23 is small and the supporting force is small. May run out. On the other hand, when the dimensional difference (d2-d1) exceeds 1.08 times the depth s of the groove 24, the groove 24 cannot completely absorb the plastic deformation due to the dimensional difference (d2-d1) and is held by excessive stress. There is a possibility that the outer periphery 25 of the metal fitting 20 may be expanded, or the assembly may be impossible.

The shape of the groove 23 provided in the press-fit recess 22 of the holding fitting 20 is not limited to a single spiral groove as in the above embodiment, but may be a parallel groove as shown in FIG. It is good also as thing of. These grooves can be formed to a desired depth s, pitch p, and angle θ (see FIG. 2) by cutting using a known inner diameter processing tool.
Also, if a known casting method is used, the groove 23 can be formed in a hatched shape as shown in FIG.

The ferrule 10 is made of Y ₂ O ₃ , MgO, Ca
It is preferable to use a partially stabilized zirconia ceramic containing a stabilizer such as O ₂ , CeO ₂ , or Dy ₂ O ₃ .

After the ferrule 10 is fixed to the holding bracket 20 as described above, the optical fiber 30 is inserted from the fiber insertion hole 21 and adhered as in the conventional example of FIG. Then, an optical connector can be formed by abutting the other ferrule having the same configuration with the tip end surface, or an optical module can be formed by bonding the ferrule to a package having a photoelectric conversion element.

Further, as another embodiment of the present invention, as shown in FIG. 6, the ferrule 10 can be fixed to a plate-like holding bracket 40 for connecting to the photoelectric conversion element.
In this case, as shown in FIG. 6, a press-fitting recess 42 is formed at one end of the holding fitting 40, and a number of grooves 44 are formed on the wall surface 43 of the press-fitting recess 42. If a photoelectric conversion element (not shown) is provided at the tip of the holding bracket 40 so as to be on an extension of the central axis of the ferrule 10,
An optical module can be configured.

The ferrule with metal fittings of the present invention is not limited to the one in which a groove is provided on the wall surface of the press-fitting recess formed in the holding metal, and a large number of protrusions 56 as shown in FIG. May be formed on the holding bracket 50. In this case, the shape of the projection 56 may be arbitrary.
As shown in FIG. 8, it may be conical.

[0023]

[Experimental example] Ferrule 1 with metal fittings of the present invention as shown in FIG.
A press-in measurement gauge was installed on an assembling press for assembling (hereinafter, the present invention), and the press-in force during assembling (at the time of press-fitting) was measured. Further, as a comparative example, the same experiment was performed using a comparative example product similar to the above-described present invention product except that no groove was provided in the wall surface 23 of the ferrule press-fitting concave portion of the support fitting 20.
The dimensions of the ferrule 1 with metal fittings are as follows.
Since it is extremely difficult to accurately measure the holding force of the ferrule, an experiment was performed this time, considering press input as an index.

[Dimensions] Ferrule outer diameter = φ3.995 ± 0.001 mm Fit depth = 4.6 mm Inventive product / depth s = 0.458 mm Pitch p = 0.706 mm Angle θ = 60 ° Inner diameter d2 = φ3.98 ± 0.02 mm d2-d1 = 0.901 mm Comparative example product / inner diameter d2 = φ3.983 + 0.01 / −0 m
m Table 1 shows the results of these experiments.

[0025]

[Table 1]

As is clear from Table 1, the conventional product has a very large press-in force, and there is a possibility that the outer peripheral dimension of the support bracket 20 changes and the diameter of the through hole 11 changes.
The product of the present invention had an average value of about 114 kgf and an ideal press-fit.

[0027]

As described above, according to the present invention, the groove formed on the wall surface inside the ferrule press-fitting recess of the holding fitting causes the wall surface to be plastically deformed when the ferrule is press-fitted, and to closely adhere to the outer peripheral surface of the ferrule. Even if the ferrule has a large holding force, and the outer diameter of the ferrule is considerably larger than the inner diameter of the ferrule press-fitting concave portion, the wall can be plastically deformed and absorbed by that amount, so that assembly is possible and the outer periphery of the metal fitting swells outward. To prevent Therefore, the dimensional tolerance may be low, and the cost is low.

[Brief description of the drawings]

FIG. 1 is an exploded sectional view of a ferrule with metal fittings of the present invention.

FIG. 2 is an enlarged cross-sectional view of a ferrule press-fitting recess formed in a holding fitting constituting the ferrule with a fitting in FIG.

FIG. 3 is a sectional view of the ferrule with metal fittings of FIG. 1;

FIG. 4 is an enlarged cross-sectional view of a ferrule press-fitting recess formed in a holding fitting constituting the ferrule with a fitting of FIG. 1 and a press fitting end of the ferrule.

5 is an enlarged cross-sectional view of a ferrule press-fitting recess formed in a holding fitting constituting the ferrule with a fitting in FIG. 1, wherein (a) is a single spiral groove, (b) is a parallel groove, and (c) is hatching. Figure shows a groove in the shape of a circle.

FIG. 6 is a sectional view of a ferrule with a fitting according to another embodiment of the present invention.

FIG. 7 is a sectional view of a ferrule with a fitting according to another embodiment of the present invention.

FIG. 8 is a perspective view showing an example of a projection formed in the press-fit recess.

FIG. 9 is a sectional view of a conventional ferrule with metal fittings.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Ferrule with metal fittings 10 Ferrule 20, 40, 50 Support metal fitting 11 Through hole 12 End part 14 Tapered surface 11a Fiber insertion port 21 Fiber insertion hole 22, 42 Ferrule press-fitting concave part 23, 43 Wall surface s Depth 24, 44 Groove 15, 25 Outer surface d1 Outer diameter d2 Inner diameter p Pitch θ Angle 56 Projection

Claims (1)

[Claims] 1. A ferrule with metal fittings, wherein one end of a ferrule provided with a through hole in the axial direction is fitted into a ferrule press-fitting recess of a holding metal having a large number of grooves or projections formed on a wall surface.