JPS623403B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an optical connector used for connecting single-core optical fiber cords that perform information communication and the like using light.

Conventionally, an optical connector plug 1 and an optical connector adapter 2 (FIG. 3) shown in FIGS. 1 and 2 have been used to connect single-core optical fiber cords. The optical connector adapter 2 joins a pair of optical connector plugs 1 together. As shown in FIG. 4, the single-core optical fiber cord 3 is constructed by covering an optical fiber core 4 with a Keppler 5 and a sheath 6 made of aramid fiber or the like. The optical fiber core 4 is a glass fiber optical fiber 6' coated with a nylon jacket 7. The optical connector plug 1 includes a cylindrical ferrule 8 into which an optical fiber core 4 is fitted.
, a plug frame 9 fitted onto the ferrule 8, a spring 10, and the plug frame 9.
A taper ring 11 is fitted between the tapered surface of the rear end and the optical fiber core 4 to sandwich the folded portion 5a of the Keppler 5, and a tightening nut 12 is loosely fitted into the plug frame 9 so as to freely rotate. and a rubber-based hood 13. The optical connector adapter 2 is divided into a cylindrical sleeve holder 14 and the sleeve 1 is split into a cylindrical sleeve holder 14.
5 is fitted inside, and the sleeve holder 14 is inserted and attached to the holder attachment hole of the housing 16 which is divided into two parts. The ferrules 8 of a pair of optical connector plugs 1 are fitted into the split sleeve 15 from both ends with their end faces abutting, and the tightening nut 12 of the optical connector plug 1 is screwed into the threaded portion 14a at the end of the sleeve holder 14. By doing so, the pair of optical connector plugs 1 are connected. In addition,
The plug frame 9 of the optical connector plug 1 has a fifth
The locking key 17 as shown in the figure is externally fitted and caulked, and the engagement piece 17a of the locking key 17 is
It is fitted into the keyway 16a of the housing 16.

However, this optical connector had the following drawbacks. First, the Keppler 5 is fixed with the plug frame 9 and the taper ring 11, and the plug frame 9 and the ferrule 8 are caulked and the ferrule 8 is
If there is looseness between the plug frame 9 and the ferrule 8, tension will be applied to the optical fiber core 4 when tension is applied to the optical fiber cord 3. may be added and disconnected. That is, in the portion 18 between the rear end surface of the ferrule 8 and the taper ring 11, tension is applied only to the optical fiber core 4, and the optical fiber core 4 is made of glass fiber and is thin.
This is because the strength is extremely low. In addition, in the part of the optical fiber cord 3 from which the sheath 6 has been removed, the coupler 5 remains exposed in the part 19 between the optical fiber cord 3 and the tapered ring 11, and there is no protection against bending, so that bending force is applied to the optical fiber cord 3. If the bending force is applied to the optical fiber core wire 4, there is a possibility that the bending force may be applied to the optical fiber core wire 4 and break it.

Another conventional example is shown in FIG.
20 is an adapter, 21 is a ferrule, 22 is a pipe, 23 is a cap, and 24 is an O-ring. In this example, the optical fiber core 4 is protected by the pipe 22, but there is no taper ring for fixing the Keppler, and the optical fiber core 4 and the ferrule 21 are only fixed by adhesive. Therefore, if the optical fiber cord 3 is bent, the optical fiber core 4 may be bent and broken, and if tension is applied to the optical fiber cord 3, the optical fiber core 4 may be directly Tension may be applied to the material and cause it to break.

7 to 9 show examples of proposed optical connectors that solve the problem of bending or breaking the optical fiber core 4 due to tension. In the figure, 30 is a pair of optical connector plugs, and 31 is an optical connector adapter. First, the optical connector plug 30 will be explained. The sheath 6 of the optical fiber cord 3 is cut off near the end to expose the optical fiber core 4, and a stainless steel pipe 32 is fitted onto the exposed portion. The rear end of the pipe 32 is embedded in the cut end surface of the sheath 6. 34 is a cylindrical ferrule into which the optical fiber core 4 is inserted together with the pipe 32. The ferrule 34 has a nut engaging flange 34a at the longitudinally intermediate portion of its outer periphery, and has a threaded portion 34b formed on the outer circumferential surface of the rear end. Ferrule 34
The opening on the rear end side is formed in a tapered surface 34c. Numeral 35 is a tightening nut for connecting the adapter, and is loosely fitted around the outer periphery of the ferrule 34 so as to be freely rotatable. The tightening nut 35 has an inner peripheral flange 35a at the rear end that engages with the nut engaging flange 34a of the ferrule, and an O-ring 36 is interposed between the nut engaging flange 34a and the inner peripheral flange 35a. . A tapered ring 37 that is fitted onto the pipe 32 from the outer surface of the Keppler 5 is fitted into the tapered surface 34c at the rear end of the ferrule 34, and the Keppler 5 is folded outward at the tip of the tapered ring 37 and then folded back. The portion 35a is the tapered surface 34 of the ferrule 34.
It is sandwiched between c. Taper ring 37
The rear end portion of the optical fiber cord 3 is formed into a cylindrical shape, and the rear end cylindrical portion 37 a is fitted onto the sheath 6 of the optical fiber cord 3 . 38 is the outer peripheral threaded portion 34 of the ferrule 34
It is a nipple screwed onto b, and there is a threaded part 3 on the outer periphery.
8a. Reference numeral 39 denotes a cap, the rear part of which fits over the optical fiber cord 3, and has a front step surface 39a on the inner surface that engages with the rear end surface of the tapered ring 37. The inner circumference of the front part of the cap 39 is the threaded part 3.
9b and is screwed into the nipple 38,
Taper ring 3 by screwing nipple 38
7 is pressed toward the ferrule 34 by the stepped surface 39a. In addition, the cap 39 has an engagement groove 39 on the rear outer circumference.
c, and a part of the cover 40 fitted onto the optical fiber cord 3 is fitted onto the cap 39 to form the engagement groove 39.
It is engaged with c. The nipple 38 is provided because the cap 39 cannot be directly attached to the ferrule 34 when assembling the connector.

The adapter 31 is formed into a cylindrical shape, and the ferrules 34 of the pair of optical connector plugs 30 are fitted into the adapter 31 from both ends so as to butt each other. The outer periphery of both ends of the adapter 31 is formed into a connecting screw portion 31a, into which a tightening nut 35 of the optical connector plug 30 is screwed. At this time, due to the elasticity of the O-ring 36, the abutting surfaces of the ferrule 34 are closely abutted so that no gaps are created. Since the adapter 31 needs to be incorporated into a circuit component, it is fixed to a housing 41 such as a chassis. That is, the adapter 31 has a middle portion formed with a large diameter, an outer periphery of which is formed as a mounting screw portion 31b, and a housing engagement flange 31c protruding from one end of the large diameter portion.
The housing 41 has an adapter fitting hole 41a,
It is fitted onto the adapter 31 and fixed by being pressed against the housing engagement flange 31c with a nut 42.
43 is Kikuzakin. The housing engagement flange 31c of the adapter 31 is provided with a pair of parallel cut-off surfaces (not shown) on its outer periphery in order to facilitate tightening of the nut 42. housing 4
An engagement groove 41b is provided in the adapter fitting hole 41a of No. 1, and a detent pin 44 is press-fitted and caulked into the housing engagement flange 31c of the adapter 31.
is engaged with the engagement groove 41b. The adapter 31 also has an engagement groove 41 that penetrates from the inner peripheral surface to the outer peripheral surface.
An air vent hole 45 communicating with b is provided.

The adapter 31 serves as a guide for aligning the optical connector plug 30 so that the fiber end faces of the optical fiber are aligned so that the light of the optical fiber does not shift.
The inner circumferential surface of is formed to fit tightly without play. Further, the inner circumferential hole of the ferrule 34 into which the optical fiber core wire 4 is inserted is similarly machined to have a precise hole diameter, and the eccentricity between the outer diameter of the ferrule 34 and the inner circumferential hole is also machined with an accuracy of several microns. The diameter of the inner circumferential hole of the ferrule 34 is approximately 25 to 200μ, but there is also a movement with a diameter of 125μ as a standard. In this way, since the adapter 31 is precisely machined, it is in a vacuum state when the optical connector plug 30 is pulled out.
The air vent hole 45 is provided for this purpose.

With such a configuration, the folded portion 5a of the Keppler 5 is connected to the ferrule 34 by the tapered ring 37.
The taper ring 37 is pressed against the tapered surface 34c, and the nipple 3 attached to the ferrule 34
8 and a cap 39, it is tightened and fixed to the ferrule 34. Therefore, even if tension is applied to the optical fiber cord 3, the tension is not applied to the optical fiber core wire 4, and the tension is borne by the Keppra 5. Therefore, the optical fiber core wire 4 is not easily cut due to tension. Furthermore, since the Keppler 5 is directly fixed to the ferrule 34 with the taper ring 37, there is no need to process the conventional plug frame 9, etc., resulting in a simple structure and easy assembly. Furthermore, since the cap 39 that is tightly fitted around the optical fiber cord 3 is fixed to the ferrule 34, the bending force can be borne by the cap 39, and therefore the bending force acting on the optical fiber core 4 is alleviated. , the optical fiber core wire 4 is prevented from being cut. In addition, a pipe 32 is connected to the optical fiber core wire 4.
Since it is externally fitted, protection against bending is even more reliable.

However, this proposed example had the following problems. That is, in order to prevent the adapter 31 from rotating idly, the housing engagement flange 3 of the adapter 31 is
Although a hole is provided in the housing engagement flange 31c and the engagement pin 44 is press-fitted therein, drilling the hole in the housing engagement flange 31c is a secondary process, which increases the number of processing steps. Also,
Since the engagement pin 44 and the hole are press-fitted, mutual dimensional tolerances must be managed. Furthermore, a press-fitting process for the engagement pin 44 is required, which increases the cost. Furthermore, since the adapter 31 and the ferrule 34 are fitted precisely as described above, an air vent hole 45 is required to remove the ferrule 34. Therefore, when the adapter 31 is tightened, there is a possibility that dust from the threaded portion 31b enters through the air vent hole 45 and adheres to the end face of the optical fiber, increasing optical connection loss.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide an optical connector that has a simple structure for preventing rotation of an adapter with respect to a housing, and that can prevent dust from entering through an air vent hole provided in the adapter.

An embodiment of this invention is shown in FIGS. 10 to 13. That is, in this optical connector, a circumferentially split cylindrical pin 49 is fitted into the air vent hole 45' of the adapter 31, and the outwardly protruding portion of the cylindrical pin 49 is engaged with the engagement groove 41b of the housing 41. It is something. In addition, the threaded portions of the nipple 38 and the threaded portions 38a, 39b of the cap 39 are formed to have some play, and the tapered ring 3 of the Keppler 5 is
The folded portion 5a sandwiched by 7 is further extended, and the extended portion 5b is connected to the nipple 38 and the cap 39.
It is inserted between the threaded parts 38a and 39b.
In addition, a pipe 32 fitted onto the optical fiber core 4
The end of the sheath 6 of the optical fiber cord 3 is deeply embedded in the cut end surface of the sheath 6 to a depth that is approximately at the rear end of the cap 39, and the rear end cylindrical portion 37a of the tapered ring 37 is formed long. and Kepra 5 are connected to the rear end cylindrical portion 37a of the tapered ring 37 and the pipe 3.
I try to sandwich it between 2 and 2. Ferrule 34
A notch 46 (first
3) is provided, and the engaging piece 47 of the detent key 47 is provided.
A is fitted. The detent key 47 has a ring-shaped portion 47b and is fitted onto the ferrule 34. The distal end portion of the engagement piece portion 47a of the detent key 47 fits into a keyway 48 formed in the connecting screw portion 31a of the adapter 31. The other configurations are the same as the proposed example shown in FIG.

With this configuration, the cylindrical pin 49 can serve both to prevent the adapter 31 from rotating and to vent air, simplifying the structure. Further, since the cylindrical pin 49 is a split pin, the diameter of the air vent hole 45' can be easily controlled. Compared to the proposed example, the hole for press-fitting the engaging pin 44 is located in the housing engaging flange 3.
There is no need to provide the engagement pin 1c, and therefore, there is no need to manage the press-fit dimensions, and there is no need to insert the engagement pin 44, which simplifies manufacturing. Furthermore, cylindrical pin 4
9 protrudes from the outer periphery of the adapter 31, the first
As shown in FIG. 2, the dust M on the threaded portion 31b is blocked by the cylindrical pin 49, making it difficult for it to enter the air vent hole 45', thereby suppressing an increase in connection loss of the optical fiber due to the dust M. Furthermore, after the attachment of the adapter 31 to the housing 41 is completed, the engagement groove 41b is closed by the washer 43 and the housing engagement flange 31c, so there is no problem of dust entering.

On the other hand, with this configuration, during assembly, the Keppler 5 is sandwiched between the outer circumferential threaded portion 38a of the nipple 38 and the inner circumferential threaded portion 39b of the cap 39 and tightened. At this time, the taper ring 37 is also tightened at the same time. Therefore, the Keppler 5 is clamped and fixed between the taper ring 37 and the ferrule 34 under tension. Therefore, when tension is applied to the optical fiber cord 3, the tension is not applied to the optical fiber core wire 4, and the tension is more reliably maintained by the Keppler 5, thereby preventing the optical fiber core wire 4 from being cut. This can be reliably prevented. Further, the pipe 32 fitted to the optical fiber core wire 4 is deeply embedded in the cut end surface of the sheath 6, and the sheath 6 and Keppler 5 are sandwiched between the rear end cylindrical portion 37a of the tapered ring 37 and the pipe 32. When a bending force is applied near the cut end surface of the sheath 6 of the optical fiber cord 3, the bending force is not directly applied to the optical fiber core wire 4, and the bending force is more reliably applied to the optical fiber core wire 4. Cutting can be prevented. Furthermore, the adapter 31
The structure is simple because the cylindrical pin 49 inserted into the air hole 45 also serves to prevent the adapter 31 from rotating relative to the housing 41. Moreover, the presence of the cylindrical pin 49 prevents dust from entering through the air vent hole 45', and prevents the connection loss from increasing due to dust. Furthermore, since the locking key 47 is provided between the adapter 31 and the ferrule 34, the following effects can be obtained. That is, insert the plug 30 into the adapter 31 and tighten the tightening nut 35.
If the ferrule 34 rotates when tightening the
The abutting end face of the optical fiber core wire 4 is rubbed and scratched, increasing connection loss, but this problem is solved. Furthermore, when inserting or removing the plug 30 into or out of the adapter 31, the rotational position of the plug 30 relative to the adapter 31 can always be kept at the same position due to the anti-rotation key 47. Therefore, there is little variation in connection loss and the reproducibility is is good. Moreover, since the locking key 47 is provided directly on the ferrule 34, unlike the conventional one shown in FIG. 1, unnecessary parts such as the plug frame 9 can be omitted, resulting in a simple structure. Also, in the one in Figure 1, the plug frame 9
When providing the detent key 17, a process such as caulking is required, but this is not necessary in this embodiment, and assembly is very easy. Also, plug 30
If excessive force is applied to the detent key 47 when inserting the lock, the O-ring 36 can absorb the force.
The detent key 47 is difficult to deform.

As described above, in the optical connector of the present invention, a cylindrical pin is fitted into the air vent hole of the adapter, and the protruding portion of the cylindrical pin is engaged with the engagement groove provided in the adapter fitting hole of the housing. Because of this, the cylindrical pin can be used both to prevent the adapter from rotating and to bleed air, making the structure simple.Moreover, since the cylindrical pin protrudes from the outer circumferential surface of the adapter, there is no possibility that dust will enter the air vent hole from the threaded part on the outer circumference of the adapter when tightening. This has the effect of preventing dust from entering the optical fiber and reducing the connection efficiency of the optical fiber.

[Brief explanation of the drawing]

Fig. 1 is a partially cutaway perspective view of a conventional optical connector plug, Fig. 2 is a partially cutaway side view thereof, Fig. 3 is a partially cutaway perspective view of a conventional optical connector adapter, and Fig. 4 is a partially cutaway perspective view of a conventional optical connector plug.
The figure is a cross-sectional view of an optical fiber cord, Figure 5 is a perspective view of the locking key of the optical connector plug in Figure 1, Figure 6 is a cross-sectional view of another conventional optical connector, and Figure 7 is a proposed optical connector. 8 is a partially enlarged sectional view of the example, FIG. 9 is an enlarged sectional view of other parts, FIG. 10 is a sectional view of an embodiment of the present invention, and FIG. 11 is a partially enlarged sectional view of the example. FIG. 12 is an enlarged sectional view of other parts, and FIG. 13 is a partially exploded perspective view. 3... Optical fiber cord, 4... Optical fiber core wire, 5... Kepra, 5a... Folded portion, 5b...
...Extending portion, 6... Sheath, 6'... Optical fiber, 7... Jacket, 30... Optical connector plug, 31... Adapter, 31b... Threaded portion, 32
...Pipe, 34...Ferrule, 34a...Nut engagement flange, 34c...Tapered surface, 35...
...Tightening nut, 37...Taper ring, 37a...
... Rear end cylinder part, 38 ... Nipple, 39 ... Cap, 41 ... Housing, 42 ... Nut, 4
5'... Air vent hole, 47... Detent key, 49
...Cylindrical pin.

Claims (1)

[Scope of Claims] 1. A pair of connector plugs having a ferrule into which an optical fiber core of an optical fiber cord is fitted, and a tightening nut loosely fitted to the outer periphery of the intermediate portion of the ferrule so as to be rotatable only; The ferrules of a pair of connector plugs are formed into a cylindrical shape that is fitted into the butt from both ends, and have connecting screw portions on the outer periphery of both ends into which the tightening nuts of the respective connector plugs are screwed, and on the outer periphery of the intermediate portion. an adapter having a housing engagement flange and a mounting thread; a housing that fits externally into the adapter and has an axial engagement groove formed in the inner peripheral surface of the adapter fitting hole; a nut that is screwed to press and fix the housing to the engagement flange of the adapter; an air vent hole provided in the adapter that opens in the engagement groove of the housing and penetrates the inner and outer surfaces; An optical connector comprising: a cylindrical pin that is inserted into a pull-out hole and whose protruding portion engages with the engagement groove of the housing. 2. A nut engaging flange with which the tightening nut engages in the axial direction is provided on the outer periphery of the ferrule, grooves that match each other are provided in the nut engaging flange and the outer surface of the adapter, and a ring is fitted onto the ferrule. 2. The optical connector according to claim 1, further comprising a locking key having a ring portion and an engaging piece portion extending from the ring portion and fitting into the nut engaging flange and the groove of the adapter.