JPS61292106A - Method for fixing tensile body of optical fiber to connector for optical fiber - Google Patents

Abstract

PURPOSE:To make operation easier and reliability higher by moving a fastener consisting of an N-T alloy in a concentrical state onto a coupler and tightening the coupler by the directional effect of the N-T alloy which restores the shape of the memorized base phase thereby fixing the coupler and inside frame. CONSTITUTION:The Ni-Ti alloy (expressed as N-T alloy hereunder) which is set at <=30 deg.C martensite transformation temp. is used for either case of a shape memory alloy or superelastic alloy. The fastener 11 formed of such N-T alloy to an annular shape is so formed that the inside diameter of the ring thereof is smaller by, for example, about 4% than the outside diameter of the coupler to be connected and fixed at the martensite transformation temp. or above. The inside diameter thereof is preliminarily expanded by about 7-8% and is held by a holding part. The coupler 62 is forced into an inside frame 12 by the force at which the N-T alloy restores the memorized shape by which an optical fiber cord 61 is held to the connector.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention This invention relates to a method for fixing Kepra, which is a tensile strength member for protecting an optical fiber core when connecting an optical fiber cord to an optical fiber connector, to an optical fiber connector.

Conventional optical fiber cords used for information transmission lines, etc. are optical fiber cores, and tensile strength members (aromatic polyamide fibers) are placed closely concentrically on the core fibers.

Furthermore, a sheath (vinyl) is covered concentrically thereon. Conventionally, optical fiber connectors have been used to connect optical fibers together.In order to attach the above-mentioned optical fiber cord to the connector, the optical fibers are connected and fixed to a ferrule, but it is necessary to firmly maintain the connection. Therefore, it was necessary to fix Keppra, a tensile strength member, to the connector. FIG. 6 shows a conventional fixing method. What is shown in FIG. 6 is a longitudinal cross-sectional view of an optical fiber connector, where 61 indicates an optical fiber cord, and from the tip of this optical fiber cord 61 excluding the sheath, Keppler 62 and optical fiber core wire 63 are separated, and An optical fiber ferrule 64 is attached to the tip of the optical fiber core 63. Here, the Keppler 62 is fixed to the outer periphery 65A of the inner frame 65 with adhesive, and a retaining collar 66 is further provided on the outer periphery of the Keppler 62.
Kepra 62 is inserted between the retaining collar 66 and the outer peripheral portion 65A.
This retaining collar 66 and the inner frame 6
In order to firmly fix the connection between the inner frame 65 and the holder 67, a method is adopted in which the Kevlar 62 is strongly held down through the retaining collar 66 through a threaded connection between the threaded part provided on the inner frame 65 and the threaded part provided on the holder 67. ing. In addition, 68 is an optical fiber ferrule 6 between the inner frame 65 which is screw-coupled with the outer frame.
4 and the compression spring 69.
The optical fiber ferrule 64 is always moved forward (6th
70 is a connection ring for attaching to an adapter (not shown) used when connecting with the other party's optical fiber connector to be connected;
1 is a hood for protecting the connection between the optical fiber cord and the inner frame.

Problems to be Solved by the Invention However, when connecting such conventional optical fiber cords and connectors, it is difficult to fix the tensile strength member, which is the primary coating, and the connector using adhesive as the main ingredient. For some reason, the reliability is questionable, and there is a problem that the adhesion deteriorates due to changes in the temperature and humidity of the surrounding environment.
In addition, when making a screw connection, the inner frame and holder must be subjected to detailed and difficult processing such as thread cutting of M 6 x P 0.5, and the screw connection may loosen due to temperature changes, vibrations, etc. There were problems such as high processing costs and a large number of parts.

Means to solve problems The present invention will be explained below based on the drawings.

FIG. 1(a) shows an embodiment of the present invention, and is a longitudinal sectional view showing a state in which an optical fiber cord and a connector are connected. In this figure, 11 is a shape memory alloy or a superelastic alloy (for example, a Ni-Ti alloy is used in either case, hereinafter referred to as an N-T alloy), and the martensitic transformation temperature is set to -30'C or less. Use this N
The fastener is a metal fitting made of -T alloy formed into an annular ring. For this tightening, the inner diameter of the annular ring of the metal fitting 11 is, for example, approximately 4
% (make the shape of the matrix to be memorized about 4% smaller than the outer diameter of Keppler), expand its inner diameter by about 7 to 8% in advance, and hold it with a holding part (for example, a connecting part). I'll let it happen.

The force of the N-T alloy returning to its memorized shape presses the Keppler 62 against the inner frame 12 and holds the optical fiber cord 61 in the connector. Since the other parts are the same as those shown in FIG. 6, they are designated by the same numbers as in FIG. 6 and their explanations will be omitted. Here, the above-mentioned tightening describes the process of expansion and contraction of the metal fitting 11. Here, even if the N-T alloy is deformed by about 8%, it returns to its original shape due to thermoelasticity. This is a load-deflection diagram schematically showing the changes in a shape memory alloy coil spring in the temperature range of the high-temperature phase (phase on the high temperature side) and the martensitic phase (phase on the lower temperature side than the transformation temperature of the N-T alloy) temperature range. explain.

In this figure, we first look at changes in the martensitic phase temperature range. When a shape-memory alloy coil spring is loaded, it undergoes elastic deformation at ■-■. When it is further loaded, it deforms from ■ to ■ while apparently yielding, resulting in ■. At this time, the relationship between load and deflection becomes nonlinear.

When the load is removed from state (2), state (2) is reached, but the strain remains. When this shape memory alloy coil spring is heated in a free state, it recovers to the state before deformation. In addition, when heating in state (■), the output load does not increase as the temperature rises, leading to (2). After that, by unloading, it recovers to ■. Next, we will look at changes in the matrix temperature range. When a shape-memory alloy coil spring is loaded, it undergoes elastic deformation at (1) - (2) and then deforms while apparently yielding due to a phase transformation called stress-induced M transformation, resulting in (2). At this time, the relationship between load and deflection becomes nonlinear. Furthermore, when the load is removed from ■, a hysteresis loop is drawn through reverse transformation and the shape returns to the shape ■ before deformation. Here, the tightening is performed by making the metal fitting 11 in the condition (■) in Fig. 7, that is, the shape to be memorized in the matrix temperature range, to a diameter that is about 4% smaller than the outer diameter of the Keppler connecting and fixing the metal fitting 11. In the site phase temperature range, it is expanded to the state shown in (1), that is, the inner diameter is expanded by about 7 to 8%, and held by a holding part. Since this retention is in the matrix temperature range under normal room temperature usage conditions, the action of returning from ■ to ■ is activated, and the tightening is done by tightening the metal fitting 11 by tightening the holding part with strong force, so it is firmly held in the holding part. It will be in a state where it is (The martensitic transformation temperature is -3
(Since the temperature is set to 0.6C or lower, the temperature used for normal optical fiber cords is in the matrix temperature range.)Then, during assembly and processing, the fitting 11 is cooled to the martensitic phase temperature range of -30"C or lower for tightening. By doing this, the state of ■ is reached, and the applied load becomes a small load of ■0■.This makes it possible to remove the metal fitting 11 with a small force. Tightening makes it easier to move the metal fitting 11.Next, by moving the metal fitting 11, the tightening becomes the state shown in ■, and the applied load becomes 0.After this, the tightening is performed by holding the metal fitting 11 on the outer periphery of Kepura. Depending on the outer temperature, tighten the metal fittings.
returns to the matrix temperature range, so the state is similar to the above-mentioned state (2), and the applied load becomes (2) 0. From this free state■
(diameter approximately 4% smaller than the outer diameter of Kepplar), the fitting 11 presses down Kepplar when tightening.
As a result, the optical fiber cord is retained.

Embodiment FIGS. 1(b) and 1(C) are diagrams showing the tightening process of an example of the embodiment of this invention, and FIG. 1(b) shows the tightening of the previous N-T alloy using the metal fittings FIG. 1(C) is a partial view of the state shown in FIG. 1(a), showing the state after tightening. In this figure, Fig. 1(b) is an example in which the metal fitting 11 is held on the outer periphery of the inner frame 12, and the inner diameter of the metal fitting 11 is memorized to be about 4% smaller than the outer diameter of the Keppler to be tightened. , a state B expanded from the outer diameter of the Keppler 62 to be tightened (for example, a state expanded by about 7 to 8%)
and is held in the inner frame 12.

Using the inner frame 12 in this state, the Keppler 62 is held and fixed. First, the sheath of the optical fiber cord 61 is removed, and the Kevlar 62 is placed in a concentric circle around the outer circumference 12A of the inner frame 12. Then, the tightening is performed by blowing cold air (for example, cold air of Freon gas using a Freon gas cylinder) into the metal fitting 11. The metal fitting 1.1 is injected, cooled to below the martensitic transformation temperature (-30"C in this case), and tightened to facilitate the movement of the metal fitting 1.1, and then tightened to place the metal fitting 11 on the Kepra 62 in a concentric state. If held as it is, the metal fitting 11 will be tightened due to the external temperature, which will rise above the martensitic transformation temperature, and as the temperature rises, the inner diameter of the metal fitting 11 will be The Keppler 62 is reduced to the memorized shape of the matrix, which is about 4% smaller than the outer diameter, and the Keppler 62 is securely fixed to the inner frame 12 by this force.The state is shown in Fig. 1(C). .

FIG. 2 is a diagram showing another embodiment, in which FIG. 2(a) shows the state before tightening, and FIG. 2(b) shows the state after tightening. In this embodiment, the Keppler 62 is held by folding back, and the slit portion 21 has one or more slits 21A around the tip of the inner frame 21 with the same <N-T alloy matrix shape.
The memorized tightening is about 4% smaller than the outer diameter of B, and the inner diameter of the metal fitting 11 is expanded by about 7 to 8% and held on the outer periphery of the inner frame 21. , and place the base ring 22 with one or more slits 22A in approximately the left half at a position to hold the Keppler 62, fold the Keppler 62 around it and bring it close together in a concentric state, and then insert the inner frame 21. Slit portion 21B with multiple slits 21A around it
After moving it to the outer periphery of the Keppler 62, the fitting 11 is tightened by injecting cold air such as Freon gas to cool it below the martensitic transformation temperature (-30°C in this case), and then tightening by moving the fitting 11. After that, tighten the metal fitting 11.
is moved above the slit portion 21B. If this state is maintained, the tightening of the metal fitting 11 will rise above the martensitic transformation temperature due to the external temperature, and as the temperature rises, the inner diameter of the metal fitting 11 will tighten due to the unidirectional effect of the N-T alloy. The Keppler 62 shrinks to the memorized shape of the matrix, which is about 4% smaller than the outer diameter, and the force causes the Keppler 62 to shrink to the inner frame 2.
1 slit portion 21B and the base ring 22, and is also fixed to the optical fiber cord 61.

FIG. 3 is a diagram showing still another embodiment of the present invention.
Figure 3(a) shows the state before tightening, and Figure 3(b) shows the state after tightening. In this embodiment, the shape of the matrix of the N-T alloy is memorized to be smaller, for example, by about 4% than the outer diameter of Kepplar, as in the above, and the tightening is performed with the inner diameter of the metal fitting 11 expanded by, for example, about 7 to 8%. The sheath of the optical fiber cord 61 is removed, and the Kepra 62 is brought into close contact with the outer periphery 31A of the inner frame 31 in a concentric manner. By injecting cold air, the martensitic transformation temperature (in this case -
After cooling to below 30"C), tightening facilitates the movement of the metal fitting 11, and then tightening moves the metal fitting 11 so that it is concentric with the top of the Keppler 62. If it is held as it is,
When tightening, the metal fitting 11 rises above the martensitic transformation temperature due to the external temperature, and as the temperature increases, due to the unidirectional effect of the N-T alloy, the inner diameter of the metal fitting 11 is approximately 4% smaller than the outer diameter of Keppra 62. The Keppler is reduced to the memorized shape of the matrix, and this tightening is performed by the force of the metal fitting 11 to securely fix the Keppler to the outer peripheral portion 31A of the inner frame 31.

FIG. 4 is a diagram showing still another embodiment of the present invention.
Figure 4(a) shows the state before tightening, and Figure 4(b) shows the state after tightening. In this embodiment, the Kevlar 62 is held on the inner frame 42 through the holder 41 and tightened with the metal fittings 11.
The shape of the matrix of N-T alloy is 1 around the tip of the holder 41.
The tightening of the metal fitting 1 is memorized to be about 4% smaller than the outer diameter of the slit portion 41B in which more than 1 slits 41A are provided.
The inner diameter of the optical fiber cord 61 is expanded by, for example, 7 to 8% and held on the outer periphery of the inner frame 42.The sheath of the optical fiber cord 61 is removed, and the Kepra 62 is attached to the inner frame
The slit part 41B, which has one or more slits 41A provided around the tip of the holder 41, is moved to the outer periphery of the Keppler 62, and then tightened with the metal fittings. 11 is injected with cold air such as Freon gas to cool it below the martensitic transformation temperature (-30°C in this case), and then the fitting 11 is tightened to make it easier to move. move it above. If you hold it as it is, tighten the metal fitting 11.
increases above the martensitic transformation temperature due to the external temperature, and as the temperature rises, due to the unidirectional effect of the N-T alloy, the inner diameter of the metal fitting 11 is approximately 4% larger than the outer diameter of the slit portion 41B.
The rekepla 62 is reduced to a slightly memorized shape of the parent phase, and by the force thereof, the rekepla 62 is reliably fixed between the outer circumferential portion 42A of the inner frame 42 and the holder 41.

FIG. 5 is a diagram showing still another embodiment of the present invention.
Figure 5(a) shows the state before tightening, and Figure 5(b) shows the state after tightening. In this embodiment, the Keppler 62 is held on the inner frame 52 by the metal fittings 11 through the hood 51, and the N
- Tightening with the shape of the matrix of the T alloy memorized to be about 8% smaller than the outer diameter of the hood, for example, the inner diameter of the metal fitting 11 is
It is held on the outer periphery of the inner frame 52 in a state in which it is expanded by about 8%. Then, the sheath of the optical fiber cord 61 is removed, and the Kepra 62 is attached to the outer peripheral portion 52 of the inner frame 52.
After fitting the hood 51 in a concentric circle around the A, and then covering the outer periphery of the Keppler 62 with the hood 51, further tighten the metal fitting 11.
For example, the cold air of Freon gas is injected to cool the metal fitting 11 to below the martensitic transformation temperature (-30°C in this case) to facilitate the movement of the metal fitting 11.
1 is moved onto the hood 51 so as to be concentric with the Keppler 62. If this state is maintained, the tightening of the metal fitting 11 will rise above the martensitic transformation temperature due to the external temperature, and as the temperature rises, the tightening of the metal fitting 11 will be reduced due to the unidirectional effect of the N-T alloy.
The inner diameter of Keppler 62 is reduced to the memorized shape of the matrix, which is about 8% smaller than the outer diameter of Kepplar 62, and this tightening is performed by the force of metal fitting 11, so that Kepplar 62 is securely fixed to outer peripheral portion 52A of inner frame 52. It is something.

DETAILED DESCRIPTION OF THE INVENTION As described, this invention does not use adhesives and
Tightening using T alloy moves the metal fittings concentrically on top of Kevlar, and returns to the memorized shape of the matrix.
The unidirectional effect of -T alloy reliably tightens Kepplar and fixes Kepplar and the inner frame. At this time, the temperature at which the metal fittings are tightened is low, for example, -30°C or lower, and unlike high-temperature work, it does not have any effect on the optical fiber cord and connector. Furthermore, tightening is easy because the metal fittings are held in advance on the connecting parts or similar parts. Furthermore, according to the present invention, it is possible to eliminate adhesives and screw processing, which increases the ease and reliability of work.
The number of parts is reduced, and processing costs are also reduced.

[Brief explanation of drawings]

Figure 1 shows an example of an embodiment of the present invention.
Figure 1 (a) is a longitudinal sectional view of the optical fiber connector, Figure 1 (b) shows the front of the tightening process, and Figure 1 (c) shows the rear of the tightening process. Partial views, Figure 2 are diagrams showing other embodiments, Figure 2 (a) shows the front tightening, Figure 2 (b) shows the rear tightening, and Figure 3 shows other examples. 1.11 Embodiments Figure 3 (a) shows the front tightening, Figure 3 (b) shows the rear tightening, and Figure 4 shows other examples. Figure 4(a) shows the front side of tightening, Figure 4(b) shows the rear side of tightening, and Figure 5 shows another example. 5(b) shows the front, and FIG. 5(b) shows the rear after tightening. FIG. 6 is a vertical cross-sectional view of a conventional optical fiber connector. FIG. 7 shows shape memory in the matrix temperature range and martensitic phase temperature range. FIG. 3 is a diagram schematically showing changes in an alloy coil spring on a load-deflection diagram. 11...Tighten the metal fittings 12.21...Inner frame 22...Foundation ring 31.42.52...Inner frame 61...Optical fiber cord 62...Keplar 65...Inner frame

Claims (1)

[Claims] (1) When connecting an optical fiber cord to an optical fiber connector, a method of fixing the tensile strength body of the optical fiber cord and the inner frame of the optical fiber connector is to cover the inner frame with a tensile strength body concentrically, and use a shape memory alloy or superelastic alloy. A slit is provided on the outer circumference of the tensile strength body or the outer diameter of the tensile strength body to store the shape of the annular inner diameter of the parent phase which is created in an annular shape using the . In addition, the inner diameter of the annular shape memory alloy or superelastic alloy is expanded from the outer diameter of the tensile strength member by providing a slit in advance on the outer diameter of the tensile strength member or the outer circumference of the tensile strength member, and is held in a holding part in a state in which the inner diameter of the annular shape memory alloy or superelastic alloy is expanded from the outer diameter of the part that holds the tensile strength member. When fixing a body, the shape memory alloy or superelastic alloy is cooled to below the martensitic transformation temperature, then moved to the outer periphery of the tensile strength body, and then the temperature of the shape memory alloy or superelastic alloy is raised to above the martensitic transformation temperature. The tensile strength of the optical fiber is applied to the optical fiber connector, which fixes the tensile strength body and the inner frame by utilizing the force that causes the annular inner diameter shape to return to the memorized shape of the matrix due to the unidirectional effect of the shape memory alloy or superelastic alloy. How to fix your body.