JPS5934887Y2 - fiber optic connector - Google Patents

Description

[Detailed explanation of the idea] The present invention relates to the structure of an optical fiber connector.

Since optical fibers are very thin and fragile, several layers of protective coatings are provided on the surface of the optical fibers to construct cables.

In order to easily connect or separate optical fibers, various types of optical fiber connectors (hereinafter simply referred to as connectors) have been put into practical use for single-fiber and multi-fiber types.

FIG. 1 is a partially cross-sectional view of an embodiment of a conventional single-core connector.

The optical fiber cable 1 consists of an optical fiber 2, a Kevlar 3 that protects it, and an outer sheath 4 that covers the Kevlar, while the connector has a coupling nut 1o and a contact 11.
The contact 11 further includes a ferrule 12.
, a body 13, a nut 14, a sleeve 15, a clamp nut 16, and other members.

In FIG. 1, the procedure for fixing the optical fiber cable 1 (hereinafter referred to as cable) to the contact 11 is as follows.

First, the cable 1 is terminal-treated by removing a necessary length of its jacket 4 to expose the Kevlar 3 and the optical fiber 2 made of a bundle of fibers.

Next, it has a cylindrical shape having an inner diameter approximately equal to the outer sheath 4 of the cable 1 shown in FIG.
7 is placed over the cable 1 from the tapered portion side, and the sleeve 15 is stopped at a position where the other end of the sleeve 15 coincides with the cut section of the jacket 4.

Then, the Kevlar 3 exposed from the other end of the sleeve is bent along the outer surface of the sleeve 15, and is placed over the outer surface of the sleeve so as to have a substantially uniform thickness.

Next, it has a cylindrical shape, and on the cylindrical surface, a protrusion 18 and two sets of screw threads are provided on both sides of the protrusion, and on the other hand, a small hole 19 large enough to allow the optical fiber 2 to pass through the central axis, A tapered surface 21 that connects to the pore and whose inner diameter decreases inward from the opening on the opposite side of the pore is formed, and when the sleeve 15 is inserted, the outer peripheral surface and the entire surface of the sleeve are formed. A nut 14 having a housing hole 20 shaped to create a substantially constant gap is placed over the cable 1 from the distal end side of the optical fiber 2 with the tapered surface 21 first.

The tapered surface 21 is the tapered portion 1 of the sleeve 15.
When the Kevlar 3 is advanced to a position where it overlaps with the sleeve 15, the Kevlar 3 placed over the outer peripheral surface of the sleeve 15 is inserted into the gap between the tapered surface 21 of the nut 14 and the tapered portion 17 of the sleeve 15.

Next, the inner circumferential surface of one of the openings has a female thread that engages with a set of threads of the nut 14, and following the female thread, there is a small diameter part with an inner diameter slightly smaller than the female thread. 22-shaped clamp nut 16 is placed over the cable from the extension side of the cable 1, and the above-mentioned female screw (which is actually fitted onto the cable in advance) is screwed into the thread of the nut 14 and rotated. Clamp nut 16 advances over nut 14.

When the tip of the tapered surface 21 of the nut 14 fits into the small diameter section 22 of the clamp nut 16, the tip of the tapered surface 21 is pressed toward the center by the inner peripheral surface of the small diameter section 19, so that the tapered surface 21 and the sleeve 15 The gap between the tapered portion 17 and the tapered portion 17 is reduced, and therefore, the end of the Kevlar 3 located in the gap is strongly compressed and fixed by both tapers.

After that, the tip of the optical fiber 2 is covered with the ferrule 12, and the optical fiber 2 is placed in the correct center of the end face of the ferrule.
The contact 11 is completed by fixing with an adhesive or the like, and polishing so that the end face of the ferrule and the end face of the optical fiber are flush with each other.

The body 13 has a female thread on a part of its inner circumferential surface that is screwed into the other set of threads of the nut 14, a shoulder 23 on the outer circumferential surface of one end, and a shoulder portion 23 on the inner circumferential surface. The body 13 is also a cylinder that forms a shoulder portion 24, and the coupling nut 10 is fitted onto the body 13 in advance, and then fitted onto the ferrule 12 and the nut 14 from the end face side of the ferrule 12 and rotated. For example, the body 13 moves forward due to the female thread on the inner circumferential surface and the thread of the nut 14, and its end surface touches the protrusion 18 of the nut 14.
At the same time, the shoulder 24 on the inner circumferential surface of the ferrule 3 is pressed against the shoulder 24 of the ferrule 3 to bring the ferrule 12 into close contact with the nut 14 and to integrate the ferrule 12 into the nut 14.

The coupling nut 10 is prevented from being pulled out forward by the shoulder portion 23, but is free to rotate, and is coupled by threading into a coupling screw (not shown) of the mating connector.

The conventional optical fiber connector configured as described above is
There are a large number of component parts, and there are many tapered parts and threaded parts, which increases the number of man-hours required to process the parts, making it expensive. This is disadvantageous in terms of high density, and since the entire assembly is done by tightening screws, there is a risk that the screws may loosen during use, causing failure of the connector.

The present invention eliminates the above-mentioned drawbacks, has fewer components, requires less man-hours for machining the parts, does not come loose during use, has a small shape, and can be applied to multi-core connectors. It is an object of the present invention to provide a suitable optical fiber connector.

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an optical fiber connector (hereinafter referred to as a connector) according to the present invention will be described below with reference to the drawings.

FIG. 3 is a partially cross-sectional external view of the connector of the present invention, which consists of a coupling nut 30 and a contact 31, and the contact 31 further includes a ferrule 32, an outer cylindrical body 40, and an inner cylindrical body 50. It consists of

The outer cylinder body 40 has an inner hole 42 with a constant inner diameter as shown in FIG.
A flat plate 44 is provided at one end of the cylinder 41 with a hole 43 through which the ferrule 32 can pass.
An annular portion 45 is formed at one end of the outer peripheral surface of the cylinder 41 continuously from the flat plate, and a shoulder portion 46 is formed at a portion of the annular portion 45 opposite to the flat plate.

Next, the inner cylinder body 50 has an external shape as shown in FIG. 5, in which FIG. 5A shows a front view, FIG. 5A shows a plan view, and FIG. 5C shows a side view.

At the center of the inner cylinder body 50 are two sets of inner holes 51 with different inner diameters.
The inner hole 52 has an inner diameter slightly larger than the outer diameter of the cable 1, and the inner hole 51 is thinner than that, and the cable with the outer jacket 4 removed to expose the Kevlar 3 is inserted through the inner hole 52. The inner diameter is set to be as large as possible, and the continuous point of the inner holes 51 and 52 forms a stepped portion 53.

The outer peripheral surface includes annular portions 54 and 55 having an outer diameter large enough to be inserted into the inner hole 42 of the outer cylinder body 40, and the annular portion 5.
4 and 55 and has a slightly smaller outer diameter, and an annular portion 56 adjacent to the annular portion 55 with a stepped portion 58 having an outer diameter approximately equal to the outer diameter of the cylinder 41 of the outer cylinder body 40. It is divided into an annular portion 57 having an annular portion 57.

A plurality of slots 59 are provided from the open end on the annular portion 54 side to the annular portion 56.

The assembly of the connector of the present invention using the above-mentioned members is performed in the following steps.

First, the cable 1 is formed by removing only the required length of the jacket 4 to expose the Kevlar 3, and further exposing the required length of the optical fiber 2 from the Kevlar end as shown in FIG.

When the cable is inserted from the tip side of the optical fiber 2 into the opening on the annular portion 57 side of the inner cylinder body 50, the removed end surface of the outer sheath 4 of the cable 1 comes into contact with the stepped portion 53. The cable will stop at this position.

Next, the exposed Kevlar 3 is distributed almost evenly according to the number of slots 59, and is drawn out to the outside of the inner cylinder body 50 through the slots 59, and then exposed to light along the outer peripheral surface of the inner cylinder body. Fold back in the direction opposite to the tip of fiber 2.

This state is shown in FIG.

At this time, the exposed length of the Kevlar 3 is determined in advance so that the folded Kevlar 3 is only on the surface of the annular part 56 of the inner cylinder body 50 and does not reach the annular part 55, or the tip of the Kevlar is trimmed after the above-mentioned folding. A means is necessary.

Next, the ferrule 32 is placed over the exposed portion of the optical fiber 2, and the optical fiber 2 is inserted so that the outer diameter of the ferrule and the optical fiber 2 are kept correctly concentric at the end surface 33 of the ferrule 32.
is adhesively fixed to the ferrule 32, and then the ferrule end face 3
3 and the end face of the optical fiber are polished and finished so that they are flush with each other.However, the bonding of the optical fiber and the finishing of the end face may be performed after attaching the outer cylinder body 40, which will be described later.

After fitting the ferrule 32, the outer cylinder body 40 with the coupling nut 30 fitted from the cylindrical end face 47 side is inserted into the cable 1 and the inner cylinder as shown in FIG. 7 with the opening of the inner hole 42 first. When the assembly with the body 50 is covered from the ferrule 32 side and moved forward, it stops at the position where the flat plate 44 of the outer cylinder body 40 abuts against the shoulder 34 of the ferrule 32, as shown in FIG. The dimensions of each member are set in advance so that the cylindrical end surface 47 of the outer cylindrical body also contacts the stepped portion 58 of the inner cylindrical body 50 at the same time.

In this state, the annular parts 54 and 55 of the inner cylinder body are in sliding contact with the inner hole 42 of the outer cylinder body 40, and the Kevlar 3 is in a press-fit state between the inner peripheral surface of the outer cylinder body and the annular part 56 of the inner cylinder body. Since the cable 1 is held between the cables 1 and 2, the cable 1 is held sufficiently against the force pulling in the direction of its extension and does not come out. Since the removed end face 6 of the outer sheath 4 is in contact with the stepped portion 53, it is also held sufficiently.

At the same time, since the Kevlar 3 is press-fitted between the inner circumferential surface of the outer cylinder body 40 and the annular portion 56 of the inner cylinder body 50 having a slightly smaller outer diameter, and a frictional force is generated, the outer cylinder body 40
The two are integrally coupled to such an extent that the inner cylinder body 50 cannot be easily separated from the inner cylinder body 50. In order to further ensure this coupling, the following measures are taken.

That is, as shown in FIG. 9a, a protruding strip 60 having a substantially triangular cross section is provided on the outer circumferential surface of the annular portion 55 of the inner cylinder body 50, while a convex strip 60 having a substantially triangular cross section is provided on the inner circumferential surface near the end surface 47 of the inner hole 42 of the outer cylinder body 40. As shown in FIG. 9, a groove 48 having a substantially triangular cross section into which the protrusion 60 can be fitted is provided at a position facing the protrusion 60 when the outer cylinder body 40 is fitted onto the inner cylinder body 50.

As a result, when the outer cylinder body 40 is placed over the assembly of the cable 1 and the inner cylinder body 50 in the state shown in FIG. 7, the protrusion 60 and the groove 48 engage as shown in FIG. However, the outer cylinder body 40 is sufficiently locked to the inner cylinder body 50.

Further, in FIG. 10, the annular portion 5 of the inner cylinder body 50
When the area A of the outer cylinder body 40 corresponding to the position 6 is pressed from the outside with a suitable tool, the Kevlar 3 is sufficiently compressed between the outer cylinder body and the inner cylinder body due to the compression of the outer cylinder body 40 as shown in FIG. The outer cylinder body 4
0 and the inner cylindrical body 50, and cooperates with the engagement between the protrusions 60 and the grooves 48 to provide a practically sufficient bonding force.

In this case, it is also possible to use a method in which the above-mentioned outer cylinder body is pressed immediately in the state shown in FIG. 8 without providing the protrusions and grooves.

Further, as the cross-sectional shape of the protruding strip 60 and the groove 48, for example, the first
Various formats as shown in Figure 2 may be used.

Furthermore, in the contact of the present invention, the rear surface 3 of the ferrule 32 is attached as shown in FIG.
5 and the end surface 61 of the inner cylinder body 50 on the side of the annular portion 59 may not be brought into close contact with each other, but the spring 70 may be interposed therebetween.

As a result, when the end surface 33 of the ferrule 32 comes into contact with the mating end surface, the spring 70 is slightly compressed, and its repulsive force can keep both end surfaces 33 in close contact with each other at all times.

With this structure, it is difficult to fix the end faces of multiple contacts so that they are on the same plane, especially when the connector of the present invention is applied to a multicore connector, and there is always axial misalignment. However, this is extremely effective because the unevenness can be absorbed by the axial movement of each contact due to the spring elasticity.

As is clear from the above description, the optical fiber connector according to the present invention has a plurality of annular portions with different outer diameters, and a plurality of slots on the outer peripheral surface from one end to the other end. By inserting the optical fiber cable into the inner cylinder body provided with a The structure is such that Kevlar is held between the outer cylinder body, the inner cylinder body, and the gap in a press-fit state, so that the optical fiber cable can be held sufficiently, and there are also protrusions and grooves on the inner cylinder body and the outer cylinder body. By providing locking pads to lock each other and pressing and compressing the outer cylinder body, it is possible to further strengthen the clamping of the Kevlar and the connection between the inner cylinder body and the outer cylinder body, so each part can be secured during use. There is no risk of it coming loose,
It has many advantages, such as a small number of parts, no need for complicated processing such as screws or tapers, and low cost, and suitable for application to multi-core connectors.

[Brief explanation of drawings]

Figure 1 is a partial sectional view of a conventional optical fiber connector, Figure 2 is a partial cross-sectional view of a conventional optical fiber connector.
The figure is a partial cross-sectional view of the sleeve used in Figure 1, Figure 3 is a partial cross-sectional view of the optical fiber connector according to the present invention, Figure 4 is a partial cross-sectional view of the outer cylinder body, and Figure 5 is a partial cross-sectional view of the outer cylinder body. A partial sectional view of the cylinder body, Fig. 6 is a diagram of the terminal processing of the optical fiber cable, and Fig. 7 is an assembly diagram of the inner cylinder body and the optical fiber cable.
Fig. 8 is a state diagram in which the outer cylinder body is further covered with the assembly of the inner cylinder body and the optical fiber cable, Fig. 9 is another embodiment of the inner cylinder body and the outer cylinder body, and Fig. 10 is the figure 9. FIG. 11 is a partial sectional view of an optical fiber connector using the inner cylinder body and outer cylinder body of FIG. 10, and FIG.
The figures show examples of the protrusions and grooves on the inner cylinder body and the outer cylinder body, and FIG. 13 is a partial cross-sectional view of still another example of the optical fiber connector of the present invention. 1... Optical fiber cable, 3... Bent Kevlar,
4゜...Outer tube body, 50...Inner tube body, 54.55.56゜57...Annular part, 5
9... Suriwari.

Claims (1)

[Scope of utility model registration request] An inner cylindrical body having an annular portion having a smaller outer diameter than the adjacent portion on a part of the outer circumferential surface and having a plurality of slots extending from the end face of one open end toward the other open end; an outer cylinder body that is fitted onto the cylinder body, and the outer cylinder body is fitted onto the inner cylinder body so that the Kevlar of the optical fiber cable is connected to the annular part of the inner cylinder body and the inner circumferential surface of the outer cylinder body. An optical fiber connector characterized by being sandwiched between.