JP2959998B2 - Optical fiber holding device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical fiber holding device used for an optical connector for connecting optical fibers.

[0002]

2. Description of the Related Art Conventionally, to connect an optical fiber, an end of the optical fiber is held by a holding device called a ferrule, and this holding device is attached to a connector or the like, and the end faces of the optical fibers to be connected are accurately butted. The fixing method is mainly adopted. In this case, if the optical fiber is slightly damaged when it is held by the holding device, it may cause breakage. Therefore, it is required to hold the optical fiber firmly so as not to damage the optical fiber and not to come off.

As a method of holding an end of an optical fiber by a holding device, a method of inserting an optical fiber into a cylindrical sleeve or the like and fixing it with an adhesive is disclosed in Japanese Patent Publication No. Hei 5-48.
As shown in No. 446, a method of inserting an optical fiber into a metal pipe or the like, mechanically caulking the metal pipe, and fixing the metal pipe, forming a cut groove halfway in the axial direction of the metal pipe, and forming a divergent shape. After inserting the optical fiber into the metal pipe as the elastic piece, a method of pressing the elastic piece to elastically tighten and fix the optical fiber, as shown in JP-A-63-18306, A method of arranging a plurality of metal tubular members having a circular cross section and holding the tubular members in a compressed state by a holding member arranged around these tubular members has been proposed. I have.

[0004]

However, in the case of fixing with the above-mentioned adhesive, it takes time for pretreatment of the optical fiber and drying of the adhesive, so that not only the productivity is poor, but also the solidification of the adhesive takes place. There was a concern that the position of the optical fiber would shift.

In the above method of directly caulking and fixing a metal pipe, if the caulking force is a little too strong, the optical fiber may be damaged such as a break, and if the caulking force is too weak, the optical fiber may come off. Therefore, there has been a problem that the staking force must be strictly controlled.

Further, in the above-mentioned method using the elastic piece formed on the metal pipe, the area for elastically holding the optical fiber is very small, so that the material of the holding part and the processing accuracy must be strictly controlled. was there.

Furthermore, in the above-described method using a tubular member having a circular cross section, since the tubular member and the optical fiber are only in line contact, a sufficient fixing force cannot be obtained and the optical fiber may come off. Was.

On the other hand, the present inventor has already proposed an optical fiber holding device as shown in FIG. 9 in order to solve the above problem (see Japanese Patent Application No. 6-329979).

This optical fiber holding device comprises a pair of hollow members 1 formed by crushing a hollow metal pipe into a semicircular cross section.
1 and 12, an optical fiber 13 is sandwiched between the central portions of the flat portions 11a and 12a, and the outer circumferences of the hollow members 11 and 12 are pressed and held by a holder (not shown).
The elastic force provided by the hollow portions 11b and 12b of the first and second embodiments allows the optical fiber to be securely held without being damaged.

However, as a result of subsequent studies, it has been found that this holding device has the following new problems.
That is, when the hollow members 11 and 12 are set in the holder and the optical fiber 13 is to be inserted into the gap between the hollow members 11 and 12, not only is it difficult for the optical fiber 13 to enter the gap, but also by mistake the hollow portions 11b and 12b Had to be inserted.

As shown in FIG. 10, the optical fiber 13 generally comprises a fiber main body 14 comprising a core 14a and a clad 14b, and a resin jacket 15 covering the outer periphery thereof. When the holding device presses and holds the optical fiber 13, it is necessary to peel off the jacket 15 at the end of the optical fiber 13 and hold the fiber body 14.

However, if the gap between the hollow members 11 and 12 is increased to make it easier to insert the optical fiber 13, the optical fiber 13 is inserted up to the portion of the jacket 15, and the optical fiber 13 cannot be firmly pressed and held. there were.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide an inexpensive optical fiber holding device in which an optical fiber can be easily inserted and fixed, and which can securely tighten the optical fiber.

[0014]

To achieve the above object, the present invention comprises a pair of hollow members opposed to each other so as to sandwich an optical fiber, and a holder for pressing and holding the outer periphery of these hollow members. An optical fiber holding device, wherein the hollow member has a semi-cylindrical shape as a whole, and a holding groove for fitting an optical fiber along an axial direction is formed in the center of a plane portion of the hollow member. An optical fiber holding part is characterized in that one end of the groove has an enlarged inner diameter of the groove to form an optical fiber introduction part, and the other end of the holding groove has an inner diameter of the groove reduced to form an optical fiber fixing part. An apparatus is provided.

[0015] In a preferred aspect of the present invention, a step is provided in the middle of the flat portion of the hollow member, and the flat portion of the holding groove has a smaller height than the flat portion around the optical fiber introduction portion of the holding groove. A flat portion around the optical fiber fixing portion has a shape withdrawn into the outer peripheral side of the hollow member.

In a further preferred aspect of the present invention, the holder is a cylindrical member having an insertion hole through which an optical fiber is adapted to be inserted, the diameter of which is reduced at the rear end with respect to the front end. And an inner diameter of one end of the optical fiber guide is such that the pair of hollow members can be inserted therein, and the rear end of the optical fiber guide is press-fitted. When the hollow member is pushed in by the rear end of the optical fiber guide, a sleeve sized to press the outer periphery thereof is provided.

According to the optical fiber holding device of the present invention,
By placing a pair of hollow members facing each other with their flat portions facing inward, inserting an optical fiber into a gap formed by the holding groove in the flat portion of the hollow member, and pressing the outer periphery of the hollow member with a holder, the hollow member Compresses and deforms to secure the optical fiber. By tightening the optical fiber through the hollow member in this manner, the optical fiber is elastically tightened and fixed, so that damage and breakage of the optical fiber are unlikely to occur, and adjustment of the pressing force and the like need not be so strict. The performance is improved.

In the conventional method of caulking a metal pipe or holding the metal pipe by using an elastic piece, the contact area between the optical fiber and the pressing portion of the metal pipe is small, so that the pressing force is low. Although it was easy for the optical fiber to be concentrated and easily damaged, and it was easy for the optical fiber to come off if the pressing force was weak, in the holding device of the present invention, the optical fiber and the hollow member were wide in the axial direction and the circumferential direction. Since the contact is made over the entire area, the pressing force is dispersed and the optical fiber is hardly damaged, and a strong fixing force against detachment is obtained.

Further, in the method disclosed in JP-A-63-18306, a sufficient fixing force cannot be obtained because the optical fiber only makes line contact with the tubular member. However, in the present invention, a hollow having a semi-cylindrical shape is used. Since the optical fiber is fitted into the holding groove formed at the center of the plane portion of the member and pressed and held, the hollow member comes into surface contact with the outer periphery of the optical fiber, and a stronger fixing force can be obtained.

Further, according to the optical fiber holding device of the present invention, the inside diameter of the groove at one end of the holding groove of the hollow member is increased to form an optical fiber introduction portion, and the groove at the other end of the holding groove is formed. Since the inner diameter of the optical fiber is reduced to form the optical fiber fixing portion, the optical fiber can be easily inserted into the gap between the hollow members by inserting the optical fiber from the introduction portion side. Further, by setting the inner diameter of the groove of the fixing portion of the holding groove to a width that does not allow the jacket portion of the optical fiber to enter, it is possible to prevent the jacket portion from entering the fixing portion. Further, at the end face on the introduction portion side, the hollow portion has a crushed shape by increasing the inner diameter of the holding groove, so that the optical fiber is not erroneously inserted into the hollow portion.

[0021]

3 to 8 show an example of a hollow member used in the optical fiber holding device of the present invention. 3 is a front view, FIG. 4 is a plan view, FIG. 5 is a right side view, FIG. 6 is a left side view, FIG. 7 is a cross-sectional view taken along line AA of FIG. 3, and FIG.
It is sectional drawing along the BB line of FIG.

The hollow member 21 is preferably obtained by press-forming a cylindrical body made of a plastically deformable material such as metal, in this embodiment, brass, and has a substantially semi-cylindrical shape as a whole. I have. The plane portion 22 has a portion 22a protruding inward via a step 23 in the middle and a portion 22b retracted to the outer peripheral side. The outer periphery 23
Is a portion 23a that is recessed inward, an intermediate portion 23b, and a portion 2 that protrudes outward through two steps 24 and 25.
3c. Portion 22 protruding inside flat portion 22
a and a portion 23a retracted inside the outer periphery 23 are substantially at corresponding positions, and a portion 22b retracted toward the outer periphery of the flat portion 22 and a portion 23c protruding outside the outer periphery 23 substantially correspond to each other. In position.

An optical fiber holding groove 26 is formed in the center of the flat portion 22 along the axial direction. One end of the holding groove 26 has an enlarged inner diameter to form an optical fiber introduction portion 26a. Further, the other end of the holding groove 26 has a reduced inner diameter of the groove to form an optical fiber fixing portion 26b. Then, the introduction section 26a and the fixing section 2
6b, the tapered portion 26 whose inner diameter gradually decreases
c.

When the pair of hollow members 21 are opposed to each other with the plane portion 22 facing inward, the inner diameter of the introduction portion 26a of the holding groove 26 is set to a size that allows the portion covered with the optical fiber jacket to be inserted. The inner diameter of the fixing portion 26b of the optical fiber 26 is an inner diameter to which the fiber main body of the optical fiber substantially fits.

As shown in FIG. 5, the end face of the hollow member 21 where the introduction portion 26a is formed has an arc shape in which the hollow portion 27 is almost crushed by the introduction portion 26a having a wide and deep groove. ing. Therefore, it is possible to prevent the optical fiber from being erroneously inserted into the hollow portion 27 when the optical fiber is inserted.

As shown in FIG. 6, the end surface of the hollow member 21 where the fixing portion 26b is formed forms a fixing portion 26b having a narrow and shallow groove, so that the hollow portion 27 is sufficiently crushed. It has a good gap. For this reason, the fixing portion 26b
The elasticity is obtained when the optical fiber is pressed by the, so that the optical fiber is not damaged.

FIGS. 1 and 2 show an embodiment of the optical fiber holding apparatus of the present invention in which the hollow member 21 is mounted on a holder. FIG. 1 shows a state before the optical fiber is tightened, and FIG. 2 shows a state where the optical fiber is tightened.

The optical fiber holding device 20 includes an optical fiber guide 31 made of ceramic such as stainless steel or zirconia, and a sleeve 41 made of stainless steel or the like.
And a pair of the hollow members 21 held in the sleeve 13 and the optical fiber 13 held between the hollow members 21. Optical fiber guide 31
And the sleeve 41 constitute a holder in the present invention.

The optical fiber guide 31 has a cylindrical shape as a whole, a front end 31a having a large outer diameter, and a rear end 31a.
b has a smaller outer diameter. Also, the shaft hole 32 of the optical fiber guide 31 has the optical fiber 13 except for the tip.
Is a size that can be loosely fitted. A guide sleeve 34 made of resin and having a guide hole 33 with an inner diameter to which the optical fiber 13 fits is inserted into the distal end of the shaft hole 32.
The guide hole 33 is gradually enlarged in diameter at the rear end face of the guide sleeve 34 to form a tapered portion 35, thereby facilitating insertion of the optical fiber 13.

A ring 36 is mounted on the outer periphery of the rear end 31b of the optical fiber guide 31. The ring 36 engages with a step 31c between the front end 31a and the rear end 31b, It does not move to the front end 31a.

The sleeve 41 has a holding hole 42 into which the hollow member 21 is inserted. The holding hole 42 communicates with an introduction hole 43 for introducing the optical fiber 13 and
It is a through hole passing through one axis. The holding hole 42 has a front end side into which the pair of hollow members 21 can be inserted, and
An enlarged diameter portion 42a having an inner diameter capable of press-fitting the rear end portion 12b of the optical fiber guide 12, and a reduced diameter portion 42b having an inner diameter capable of pressing the pair of hollow members 21 at the rear end side.

The outer periphery of the distal end of the sleeve 41 is a reduced diameter portion 41a, and an annular body 44 is mounted on the outer periphery. The ring body 44 is engaged with the step portion 41b so as not to move backward. The ring 44 is a portion fixed to an optical connector (not shown). A coil spring 45 is mounted between a ring 36 mounted on the outer periphery of the rear end of the optical fiber guide 31 and a ring 44 mounted on the outer periphery of the sleeve 41.

The rings 36 and 44 and the coil spring 4
Numeral 5 is provided for elastically abutting the tip of the optical fiber guide 31 when abutting the member to be connected, but these are not necessarily required in the present invention.

Next, a method of using the optical fiber holding device 20 will be described. First, as shown in FIG. 1, a pair of FIG.
8 are inserted from the introduction portion 26a side in a state where the flat portions 22 are abutted on each other. Also,
The ring body 44 and the coil spring 45 are mounted on the outer circumference of the reduced diameter portion 41 a of the sleeve 41. In this state, the rear end 31 b of the optical fiber guide 31 to which the ring 36 is attached is inserted into the enlarged diameter portion 42 a of the holding hole 42 of the sleeve 41.

Then, the end of the optical fiber 13 to be connected is passed through the introduction hole 43 of the sleeve 41, further between the pair of hollow members 21, and further through the shaft hole 32 and the guide hole 33 of the optical fiber guide 31. The optical fiber guide 31 is projected from the front end face. At this time, the end of the optical fiber 13 is peeled off the jacket 15 by a predetermined length, leaving the fiber main body exposed. The optical fiber 13 is connected to the introduction portion 2 of the holding groove 26 of the hollow member 21.
6a, it can be easily inserted.
In addition, the portion where the jacket 15 is attached is
a, but cannot be inserted into the fixing portion 26b. The optical fiber 13 is fitted and held in the holding groove 26 of the hollow member 21.

After setting the optical fiber 15 in this way, as shown in FIG. 2, the rear end 31b of the optical fiber guide 31 is connected to the enlarged diameter portion 42a of the holding hole 42 of the sleeve 41.
Push strongly into the back. As a result, the pair of hollow members 21
Is pushed into the reduced diameter portion 42b of the holding hole 42 from the introduction portion 26a side, as shown in FIG. At this time, the hollow member 2
Since the steps 24 and 25 are provided on the outer periphery 23 of the first member 1 and the outer diameter on the introduction portion 26a side is reduced, the hollow member 21 can be easily pushed into the reduced diameter portion 42b of the holding hole 42.

Further, the fixing portions 26b of the pair of hollow members 21
The peripheral flat portion 22b has a shape recessed toward the outer peripheral side, and the outer periphery 23c of that portion has a shape protruding outward. Therefore, the outer periphery 23c of the portion of the hollow member 21 where the fixing portion 26 is provided is formed. , Is effectively pressed by the reduced diameter portion 42b of the holding hole 42. As a result, the optical fiber 13 is pressed and fixed between the fixing portions 26 b of the pair of hollow members 21. Further, since the pressing force of the hollow member 21 is elastically provided by the hollow portion 27, it is possible to prevent the optical fiber 13 from being damaged. After the optical fiber 13 is fixed, the portion of the optical fiber 13 protruding from the tip of the optical fiber guide 31 is cut by a conventional method and polished as necessary.

As described above, the optical fiber holding device 2
0, the optical fiber 13 is elastically fastened and fixed by the pair of hollow members 21 having the hollow portion 27, so that the optical fiber 13 is hardly damaged and the contact area can be increased in the axial direction and the circumferential direction. Can be fixed firmly.

[0039]

As described above, according to the optical fiber holding device of the present invention, the flat portions of a pair of substantially semi-cylindrical hollow members are arranged to face each other, the optical fiber is sandwiched between these flat portions, and the holder is held. Press the outer periphery of the hollow member with
Since the optical fiber is elastically fastened and fixed, the optical fiber is hardly damaged, and the contact area can be increased in the axial direction and the circumferential direction to be firmly fixed. Further, since the hollow member is fixed by utilizing the elasticity when pressed, it is not necessary to strictly adjust the pressing force and the processing accuracy, and the productivity can be improved. Further, a holding groove for the optical fiber is formed at the center of the plane portion of the hollow member, and the holding groove has an inner diameter of the groove at one end which is increased to form an introduction portion of the optical fiber, and a groove at the other end. Since the inner diameter of the optical fiber is reduced and the optical fiber is fixed, the optical fiber can be easily and reliably inserted into the holding groove of the hollow member when the optical fiber is inserted with the hollow member attached to the holder.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing an embodiment of an optical fiber holding device of the present invention, showing a state before an optical fiber is tightened.

FIG. 2 is a cross-sectional view showing a state where an optical fiber of the optical fiber holding device is tightened.

FIG. 3 is a front view showing an example of a hollow member used in the optical fiber holding device of the present invention.

FIG. 4 is a plan view of the hollow member.

FIG. 5 is a right side view of the hollow member.

FIG. 6 is a left side view of the hollow member.

FIG. 7 is a sectional view taken along line AA of FIG. 3;

FIG. 8 is a sectional view taken along the line BB of FIG. 3;

FIG. 9 is a perspective view showing a main part of the optical fiber holding device filed before the present application.

FIG. 10 is a perspective view showing a general shape of an optical fiber.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 13 Optical fiber 20 Optical fiber holding device 21 Hollow member 22 Flat part 22a Inwardly protruding part 22b Outer part retracted 23 Outer part 23a Inwardly retracted part 23c Outwardly protruding part 26 Holding groove 26a Introducing part 26b Fixing part 31 Optical fiber guide 32 Shaft hole 33 Guide hole 41 Sleeve 42 Holding hole 42a Large diameter portion 42b Small diameter portion

Claims (3)

(57) [Claims] 1. An optical fiber holding device comprising: a pair of hollow members opposed to each other so as to sandwich an optical fiber; and a holder for pressing and holding the outer periphery of these hollow members. It has a cylindrical shape, and a holding groove for fitting an optical fiber along the axial direction is formed at the center of the plane portion, and one end of the holding groove has an increased inner diameter of the groove to introduce the optical fiber. An optical fiber holding device, wherein the other end of the holding groove has an inner diameter reduced to form an optical fiber fixing portion. 2. The flat portion of the hollow member is provided with a step in the middle thereof, and the flat portion of the holding groove around the optical fiber fixing portion of the holding groove is compared with the flat portion around the optical fiber introduction portion of the holding groove. The optical fiber holding device according to claim 1, wherein the flat portion has a shape withdrawn into the outer peripheral side of the hollow member. 3. The holder is a cylindrical member having, at the center, an insertion hole into which an optical fiber is fitted and inserted,
An optical fiber guide whose rear end is reduced in diameter with respect to the front end, and the inside diameter of one end is such that the pair of hollow members can be inserted, and the rear end of the optical fiber guide is press-fitted. 3. A sleeve having a size and an inner diameter at the other end, the sleeve having a size capable of pressing the outer circumference when the pair of hollow members are pushed in by the rear end of the optical fiber guide. The optical fiber holding device as described in the above.