JPH0356446B2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to an optical connector.

FIG. 1 is a broken sectional view showing a state in which optical connectors A in a conventional example are connected to each other, and 1 in the figure.
is an adapter that connects the optical connector bodies A to each other. 2 is a ferrule, and an optical fiber 15 is inserted through the axial center of the ferrule 2 and fixed with an adhesive. A coil-shaped spring 12 is interposed in the rear part of the ferrule 2, and the rear part of the ferrule 2 is positioned within the plug frame 4 formed in a substantially cylindrical shape, and the ferrule 2 is inserted into the insertion hole 20 at the bottom of the plug frame 4. The rear end of the ferrule 2 is inserted, and the E-ring 7 is fitted into an E-ring groove cut into the rear end of the ferrule 2, thereby holding and fixing the ferrule 2 to the plug frame 4. At this time, in order to prevent the ferrule 2 from rotating freely in the circumferential direction relative to the plug frame 4, a key shape is formed at the rear of the ferrule 2 to prevent it from rotating, and this key shape is provided on the side of the plug frame 4. A key groove is formed into which the key can be inserted. Furthermore, a key ring 5 having a key that fits into the adapter 1 is pressed on the outer periphery of the plug frame 4 to prevent the optical connector main body A from rotating idly when the optical connector main body A is inserted into the adapter 1. The reason why it is not desirable to let the ferrule 2 idle in this way is to prevent the end surfaces of the optical fibers 15 of the ferrule 2 from rubbing against each other and being damaged.
The tip end face of the optical fiber 15 is exposed to the end face of the ferrule 2. A plug joint 6 is coupled to the rear of the plug frame 4, and a tightening nut 8 is provided on the outside of the plug frame 4 and the plug joint 6. Ferrule 2 is spring 12
The optical fiber 15 is biased toward the distal end side, thereby obtaining contact pressure with the other optical fiber 15 to be connected. 9 is a cap that covers the rear outer periphery of the plug joint 6 and the optical fiber cord 17 extending from the rear of the plug joint 6; 11 is a hood that covers the cap 9 and the optical fiber cord 17; 3'
is the split sleeve built into adapter 1,
This split sleeve 3' is used for aligning the outer diameter of the ferrule 2 when connecting the optical fiber 15.
10 is a taper ring, 13 is a washer, and 14 is a fixing nut.

FIG. 2 shows a sectional view of the adapter 1, which is composed of a pair of adapter housings 1a, 1a and a pair of sleeve holders 3a, 3a, and a split sleeve 3' is held by a pair of cylindrical sleeve holders 3a, 3a. I try to do that. That is, the recess 3 formed in the inner peripheral surface of both sleeve holders 3a, 3a
The split sleeve 3' is positioned and fixed within b,
Further, the sleeve holder 3a has a protrusion 3c that protrudes in an annular shape around the center thereof, and is positioned and fixed from both sides by the protrusion 1b provided on the inner circumference of the adapter housing 1a. Both adapter housings 1a, 1a are fixed with screws 23 at a flange portion 1c provided annularly around the central portion. Therefore, the split sleeve 3' is supported and fixed by the sleeve holder 3a and the adapter housing 1a. FIG. 3 shows a front view and a side view of the split sleeve 3', in which one slit 21 is formed over the entire axial length of the outer circumference of the cylindrical split sleeve 3'. FIG. 4 shows another conventional example of the split sleeve 3', in which three slits 21 are formed on each side of the split sleeve 3'. The inner circumferential surfaces of these split sleeves 3' abut on the outer circumferential surfaces of the two ferrules 2 to be connected so as to straddle the two, thereby supporting both the split sleeves 3', 3'.

Here, a split sleeve 3' as shown in FIG.
Even when using a ferrule, if there is a difference in the outer diameter of the left and right ferrules 2, 2', the following disadvantages occur. That is, as shown in FIG. 5, the outer diameter of one ferrule 2 is φD ₁ , and the outer diameter of the other ferrule 2'
The outer diameter of is φD ₂ , and the size relationship of the outer diameter is φD ₂ > φD ₁
It is. When both ferrules 2, 2' are supported by split sleeves 3', the ferrule 2' with the larger outer diameter
However, the ferrule 2, which has a small outer diameter, is supported by the split sleeve 3' because it is supported at three points: the inner central part X of the split sleeve 3' and the parts Y and Z on both sides of the slit 21. You will become free without being affected. Then, as shown in Figure 5a (a),
An axis deviation of at least φD ₂ −φD ₁ /2 will occur.

FIG. 6 shows a drawback that occurs when a split sleeve 3' having both ends split at the slits 21 as shown in FIG. 4 is used. That is, since both sides of the split sleeve 3' are split at the slits 21, if the ferrule 2 is inserted from both sides, both sides of the split sleeve 3' will expand, and the outer diameter of the ferrule 2 will adjust to the expansion. , even if there is an inclination θ between the end faces of both ferrules 2, the ferrule 2
The problem is that the end face is tilted, creating a gap.

Furthermore, FIG. 7 shows a diagram for explaining the problem that commonly occurs in split sleeves 3', and the split sleeves 3' shown in FIGS. 3 and 4 are both split by providing a slit 21. Therefore, as shown in FIG. 7b, dirt 22 and the like enter the split sleeve 3' through the slit 21, and as a result,
A gap (b) as shown in Fig. 7c is created between the end faces of both ferrules 2 due to this dust 22,
There was a problem that connection loss increased.

FIG. 8 shows a split sleeve 3' directly supported by the adapter housing 1a.
An annular protrusion 24 is provided protruding from the inner peripheral surface of the center portion of the adapter housing 1a, and a threaded portion 25 is formed inside the protrusion 24. An annular groove 26 is cut into the outer circumferential surface of the central part of the split sleeve 3'.
This groove 26 and the protrusion 24 are adapted to engage with each other. Further, a threaded portion 27 is formed on the outer peripheral surface of one end of the split sleeve 3', and this threaded portion 27 is screwed into the threaded portion 25 of the adapter housing 1a. That is, the split sleeve 3' is inserted into the adapter housing 1a from the side having the threaded part 25, the threaded parts 25 and 27 are screwed together, and the split sleeve 3' is passed through, the protrusion 24 and the groove 26 are engaged, and the split sleeve 3' is inserted into the adapter housing 1a. 3' is supported and fixed to the adapter housing 1a.

In FIG. 9, instead of the threaded parts 25 and 27 shown in FIG.
8 and 29, respectively. The split sleeve 3' has elasticity, and when the split sleeve 3' is inserted into the adapter housing 1a, the tapered part 2
The split sleeve 3' is supported and fixed to the adapter housing 1a by engaging the protrusion 24 in the groove 26 via the grooves 8 and 29. Since the split sleeves 3' shown in FIGS. 8 and 9 both have the slit 21, they suffer from the problems described above.

The present invention has been provided in view of the above-mentioned points, and it is an object of the present invention to more accurately align the outer diameter of a ferrule with a sleeve, prevent the intrusion of dust, etc., and reduce the connection loss of an optical fiber. The objective is to provide an optical connector for this purpose.

Embodiments of the present invention will be described in detail below with reference to the drawings. The gist of the present invention is the shape of the sleeve 3. As shown in FIG. 10, the sleeve 3 is formed into a cylindrical shape, and the outer peripheral surface is completely closed to prevent dust from entering from the outside. There is. In order to insert the ferrule 2 from both sides of the sleeve 3, thick portions 30 are formed on both sides of the sleeve 3 with the axial center portion as a boundary. A groove 31 having an arc-shaped cross section is formed in the thick wall portion 30 of the cross-sectional layer of the sleeve 3.
is cut in the axial direction of the sleeve 3, one end of the groove 31 opens into the sleeve 3 from the thick part 30, and the other end of the groove 31 is closed within the thick part 30. . The grooves 31 are formed on both sides of the sleeve 3, and three or more (four in this embodiment) grooves 31 are equally formed in the thick wall portions 30 on both sides. Further, the thick portion 30 between the groove 31 and the inside of the sleeve 3 is formed as an elastic contact piece 32 that makes elastic contact with the outer peripheral surface of the ferrule 2. This elastic contact piece 32 has elasticity and has a biasing force so that the outer diameter of the ferrule 2 is focused on the center of the inner diameter of the sleeve 3.
Further, the inner diameter of the sleeve 3 is precisely formed to be slightly smaller than the outer diameter of the ferrule 2, and has an interference margin of the outer diameter of the ferrule 2. Naturally, even if the outer diameter of the ferrule 2 is inserted, the sleeve 3 can be smoothly inserted into the tightening margin.

In FIG. 11, the ferrule 2 is inserted into the sleeve 3, and the sleeve 3 is supported by the adapter housing 1a. The method of engagement between the sleeve 3 and the adapter housing 1a is the same as that shown in FIG. Ferrules 2 have different outer diameters, and one ferrule 2
The outer diameter of the ferrule 2' is φD ₁ , and the outer diameter of the other ferrule 2' is φD ₂ , and the relationship is φD ₂ >φD ₁ . The sleeve 3 is inserted into the adapter housing 1a, passes through the threaded portions 25 and 27, and the protrusion 24 is engaged in the groove 26. Then, the ferrules 2 are inserted from both sides of the sleeve 3, respectively. At this time, the outer peripheral surfaces of the ferrules 2 and 2' are connected to each elastic contact piece 3 of the sleeve 3.
2, they are brought into elastic contact with each other so as to converge at the center of the sleeve 3. Therefore, even if the outer diameters of both ferrules 2, 2' are different, both ferrules 2, 2' are located at the center of the sleeve 3, and the end faces of the optical fiber 15 of the ferrules 2, 2' are relative to each other. will be faced. As shown in FIG. 11a, no axis misalignment occurs between the ferrules 22'.
Furthermore, since the outer circumferential surface of the sleeve 3 is closed, no dust can enter from the outside, and no gap is created between the end faces of the ferrule 22', thereby preventing an increase in connection loss.

From FIG. 12 onward, the ferrule 2, the rear part, and the optical fiber cord 17 of the optical connector main body A are configured in an L-shape, making it difficult to apply external loads and making it compact. . This is designed to prevent light from passing through due to the optical fiber cord 17 being bent by a hand or a component hitting the optical connector main body A, or by being pulled onto the optical fiber cord 17 and breaking the optical fiber 15. . That is, the plug joint 6 is formed into an L-shape and half-split shape, and this plug joint 6 has L-shaped semicircular grooves 33 and 34 into which the optical fiber 15 and the optical fiber cord 17 can be inserted. It is formed as shown in FIG. At this time,
The semi-circular groove 33 that holds the optical fiber 15 is formed so as to leave a gap so that even if the ferrule 2 is pressurized, no compressive force is applied to the optical fiber 15, so that the optical fiber 15 is slightly shaken. On the other hand, the semi-circular groove 34 for holding the optical fiber cord 17 is formed to have a size similar to that of the seam. Plug joint 6
The L-shaped bending portion has an appropriate radius radius so that the optical fiber 15 can be bent easily. A bellows 35 or a hood 11 is formed at the base of the plug joint 6 to cushion the optical fiber cord 17 from bending. Alternatively, a bellows 35 or a hood 11 can be incorporated. As described above, the plug joint 6 is split in half, and both halves are connected by a thin bent portion 36.
6, which can be opened and closed as shown in FIG. Fig. 14 shows another embodiment of the plug joint 6, in which the plug joint 6 is completely divided in half and assembled, and the other structure is the same as that shown in Fig. 13. The same is true. In order to fix the Keppler 37 of the fiber cord 17, a V-groove-shaped protrusion 38 is provided on the half-split surface of the plug joint 6.
are formed under a plurality of conditions as shown in FIG.
It is fixed by sandwiching it in a sandwich shape. At this time, adhesive is applied to the halved surface of the plug joint 6. Further, instead of the V-groove-shaped projection 38, as shown in FIG. 16, a large number of triangular pyramid-shaped projections 38' may be provided on the half-split surface of the plug joint 6. In Fig. 12, numeral 39 is a chassis, and assuming that the dimension between the chassis 39 and the curved portion of the plug joint 6 is _L1 , Fig. 1 shows the case where the plug joint 6 is made straight. The overall length of the optical connector body A is shorter than the dimension _L2 , making it more compact. Also, since the plug joint 6 is configured in an L-shape, the 12th
As shown in the figure, the chassis 39 that fixes the optical connector body A and the optical fiber cord 17 are parallel to each other, making it difficult for external loads to be caught on or applied to the optical fiber cord 17. It can prevent deformation and damage. Also,
Since the Keppler 37 of the optical fiber cord 17 is fixed with the protrusion 38 on the half-split surface of the halved plug joint 6, fixing of the Keppler 37 is easy, and assembly is easy and operability is improved. It's good.

As described above, the present invention provides an optical connector including:
The sleeve is formed into a cylindrical shape with a closed outer peripheral surface, and thick parts are provided around the cross-sectional layers on both sides of the sleeve, with a thin-walled part at the center in the axial direction as a boundary, and thick parts are provided around the cross-sectional layers on both sides of the sleeve. A plurality of grooves each having a substantially arcuate cross section are cut in the axial direction of the sleeve, one end of each of which is open inside the cross-sectional layer and the other end of which is closed, and the end surface is formed into a relative surface corresponding to the thin wall portion. Elastic contact pieces are formed in the cross-sectional layer between the groove and the inside of the sleeve so that the ferrule located inside the sleeve comes into elastic contact with the outer peripheral surface of the ferrule and is focused at the center of the inner diameter of the sleeve. Therefore, when the ferrules are inserted into the sleeve, the elastic contact pieces inside the sleeve bring the ferrules on both sides into elastic contact so as to converge them to the center of the sleeve's inner diameter, so that the ferrules are attached to each other at the center of the sleeve. Therefore, even if ferrules with different outer diameters are inserted from both sides of the sleeve, there will be no axis misalignment as in the conventional case, and both ferrules are elastically supported at the center of the inner diameter of the sleeve by elastic contact pieces. In this way, the outer diameter of the ferrule can be aligned with high precision, resulting in an effect of reducing connection loss. Moreover, when the ferrule is inserted into the sleeve, the elastic contact piece forces the ferrule into elastic contact with the center of the shaft, so there is no need for any other special construction. Optical fiber can be connected,
Particularly in on-site construction, the connection work can be done quickly, which has the effect of improving work efficiency. In addition, since the sleeve does not have a split like in the past, and its outer circumferential surface is closed, it is difficult for dust to enter the sleeve, and the end face of the optical fiber is not left with any gaps or scratches due to dust. This has the effect of reducing connection loss.

[Brief explanation of drawings]

Fig. 1 is a broken sectional view showing a connected state of a conventional optical connector main body, Fig. 2 is a sectional view of the same adapter, Figs. 3 a and b are front and side views of the above sleeve, and Fig. Figures a and b are a front view and a side view of another conventional example of the above sleeve, Figures 5 a and b are longitudinal sectional views and cross sectional views showing the state in which ferrules with different outer diameters are inserted, and Figure 6 The figure is an explanatory diagram of the operation when using the same sleeve with cracks on both sides. Figures 7 a, b, and c are explanatory diagrams of the operation showing a state in which dust has entered through the slits in the sleeve of the same. Figure 8 is the operation explanatory diagram of the same as the above. FIG. 9 is a sectional view showing another engaged state of the sleeve and the adapter housing. FIGS. 10 a and 10 b are a front view and a side view of the sleeve according to the embodiment of the present invention. , FIGS. 11a and 11b are a cross-sectional view and a longitudinal sectional view showing the engaged state of the same as above, FIG. 12 is a broken sectional view of the same as the above when the plug joint is shaped into an L-shape, and FIGS. 13a and b 14 is an exploded perspective view of another embodiment of the above plug joint, and FIG.
FIG. 5 is an enlarged perspective view of the main part of the same plug joint as above, and FIG. 16 is an enlarged perspective view of the main part showing another embodiment of the protrusion of the same plug joint as above. 2 is a ferrule, 3 is a sleeve, 15 is an optical fiber, 30 is a thick part, 31 is a groove, 32 is a cutting piece,
A indicates the optical connector body.

Claims (1)

[Claims] 1. When connecting optical connector bodies, the end surfaces of the optical fibers in both ferrules are made to face each other using a sleeve that spans the outer periphery of both ferrules of both connector bodies, and the axes of both ferrules are aligned. In the optical connector, the sleeve is formed into a cylindrical shape with a closed outer circumferential surface, and thick portions are provided around the cross-sectional layer on both sides of the sleeve with a thin wall portion at the center in the axial direction as a boundary, A plurality of grooves having a substantially arcuate cross section are cut in the axial direction of the sleeve, one end of which is open inside the cross-sectional layer and the other end of which is closed, in both thick parts of the layer, corresponding to the thin part. A cross-sectional layer between the groove and the inside of the sleeve is provided with an elastic contact piece for elastically contacting the outer peripheral surface of the ferrule located inside the sleeve with its end faces facing each other and converging the ferrule at the center of the inner diameter of the sleeve. 1. An optical connector characterized in that the optical connector is formed by forming the respective parts.