JPH01206305A - Manufacture of pin fitting type connector for optical fiber - Google Patents

Abstract

PURPOSE:To execute a physical contact of the end face of a core by working the tip of a connector body to a pyramidal or conical surface and polishing the tip of the core positioned at the apex of the tip of the connector to a projecting curved surface. CONSTITUTION:One end of a core 2 is inserted into a core insertion hole, fixed to the inside surface of the core insertion hole by an adhesive agent, and thereafter, brought to grinding by a polishing material, and an inclined surface where the tip of the core 2 is the apex is formed. As for the inclined surface of the tip of a connector 1, it is a necessary and sufficient condition that the apex of a cone or a pyramid which is formed by the inclined surface coincides with the center of the core, and as for the inclined surface, a plane or a curved surface will suffice. In such a way, since the end face of the core 2 is positioned at the apex of the tip of the connector 1, it becomes possible to apply a curved surface processing to the tip of the core 2 by an elastic grinding machine. Therefore, a junction by a physical contact of the core 2 can be executed.

Description

Detailed Description of the Invention 3.1. Purpose of the Invention [Industrial Field of Application of the Invention] This invention relates to a method of forming and processing a so-called pin-fitting connector for optical communication cables.

The tips of the core wires of the bottle-fitting connector are joined by direct pressure contact (physical contact), and the transmission efficiency of the joint surface is improved.

The present invention can be used in a manufacturing method for manufacturing optical communication cable connectors that do not require the presence of joining oil, grease, etc.

[Prior art and its problems] Conventional methods for manufacturing pin-fitting type connectors are generally comprised of the following steps for both single-core connectors with one core wire and multi-core connectors with two or more core wires. There is.

That is, a plastic connector body having a positioning pin fitting hole for fitting a pair of left and right guide pins p and a core wire insertion hole located at the midpoint between both positioning pin fitting holes] is formed by transfer molding or the like. For the product molded by Select only those with an error of 1 μ or less between the centers of the connector, insert one end of the core wire 2 into the core wire insertion hole of the connector, and fix it to the inner surface of the hole by adhesive. The contact surface is polished with a diamond film or the like to make it flat and smooth (the surface roughness of the core wire end surface is 1μ or less).

A pair of connectors made in this way are connected by inserting and fitting guide pins P having tapered ends into the positioning pin fitting holes.

At this time, the core wires 2 are butted and joined with the centers of their end surfaces aligned with each other.

Even if the core wire abutting surface of the connector is polished to a surface roughness of 1μ or less, there are microscopic irregularities, and these irregularities create an air layer where fine air M is interposed between the bonding surfaces of the core wires 2. Due to the presence of , Fresnel reflection occurs at the bonded surface, significantly reducing transmission efficiency.

In order to prevent this, the presence of the fine air layer is eliminated by applying oil or grease having the same refractive index as the core wire to the end face of the core wire.

For the conventional connectors mentioned above, it is essential to apply oil, etc. to the end face of the extremely thin core wire evenly and to prevent air from being trapped. This will result in poor bonding. Further, during a long period of service, intermediates such as oil may deteriorate and air may enter, reducing transmission efficiency. When disconnecting the connector and reconnecting it, it is necessary to completely wipe off any intermediate substances such as oil that have adhered to the end face of the core wire, and then apply new oil or the like.

Due to the problems mentioned above, it is desired to improve the transmission efficiency of the joint surface of the core wire in pin-fitting type connectors without intervening intermediates such as oil or grease between the end surfaces of the core wire. It was.

After the connector body 1 is molded, the distance between the centers of the first positioning pin fitting hole and the core wire insertion hole is precisely measured.

This measurement was performed using a microscope.

If this measured value is 1μ or more with respect to the standard dimension, it is excluded as defective. If there is an error of 1 μ or more, the core wires butt-joined to each other will have a misalignment of 2 μ or more. This precise measurement is performed in order to suppress the reduction in transmission efficiency due to eccentricity to a sufficiently small range. The distance between the center of the core wire insertion hole is measured using a microscope when the positioning pin is fitted into the hole. Measurement cannot be carried out, and the efficiency of measurement work is reduced.

Therefore, conventionally, pin-fitting type connectors for this measurement work have always had their tip surfaces made flat.

In so-called cylindrical single-core connectors, the cylindrical connectors are inserted from both ends of one cylindrical body, and the left and right connectors are aligned using the cylindrical body, so the above problem with pin-fitting type connectors does not exist. do not. That is, the end surfaces of the connectors that are butted against each other are spherical surfaces,
By positioning the tip of the core wire at the apex, only the end faces of the core wire are pressed against each other, thereby crushing the fine irregularities on the end face of the core wire and joining in a so-called physical contact state. The above problems caused by the existence of .

However, with regard to pin-fitting type connectors, joining by physical contact of core wires has not been realized due to the restriction that the joining end surface must be flat for the above-mentioned precision measurement using an M-microscope.

[Invention Section M] An object of the present invention is to enable physical contact of the end faces of the core wires with respect to the above-described manufacturing method of the pin-fitting type connector without causing any hindrance to the precise measurement using a microscope. It is.

3.21 Structure of the Invention [Means taken to solve the problem] In order to clarify the means of the present invention, the manufacturing process of a conventional pin-fitting type connector is summarized as follows.

(a) Using a plastic material, mold a connector body having a pair of left and right positioning pin fitting holes and a core wire insertion hole located at the midpoint between the two fitting holes.

(b) Using a microscope, precisely measure the center-to-center distance between the core wire insertion hole and the positioning pin fitting hole that are open in the flat end surface of the connector body taken out from the mold.

(c) For those whose center-to-center distance is within the tolerance range, one end of the core wire is inserted into the core wire insertion hole and fixed to the inner surface of the core wire insertion hole with adhesive.

(d) Polish the end face of the connector body with a diamond film or the like to make it smooth and flat.

The means of the present invention includes (a) adding a simple cutting process between the above steps (c) and (d) to form an inclined surface with the tip of the core wire as the apex, and (b) the apex of the connector. The polishing process using a diamond film or the like is used as a curved surface process to make the end face of the core wire into a convex curved surface.

For cutting the end face of the connector body, grinding using an abrasive material is efficient and practical.

Any cutting method may be used as long as the four corners of the tip of the connector body are cut down to form an inclined surface, and cutting with a knife or cutting with an ultra-high-speed fluid jet may be used. However, it is not possible to adopt a cutting method that may cause permanent distortion in the end face by excessively machining or heating the tip of the connector main body. This is because this processing causes a deviation in the center-to-center distance between the positioning pin fitting hole of the connector and the core wire insertion hole, and also causes distortion in the adhesion to the optical fiber.

Regarding the inclined surface at the tip of the connector, it is a necessary and sufficient condition that the apex of the cone or pyramid formed by the inclined surface coincides with the center of the core wire, and its shape does not matter at all. . Therefore, the inclined surface may be a flat surface or a curved surface.

In terms of actual work efficiency, cutting is performed using a rotating grinder, but in the same way as cutting the tip of a pencil into a conical shape with a conical cutting blade that rotates and revolves, it is possible to cut the tip of a connector into a conical shape. It is also possible to adopt a cutting method in which the material is cut into a conical shape.

However, in the case of a multi-core connector, it is necessary to make the apex into a long straight line along the arrangement of a large number of core wires, so this cutting method cannot be adopted as a cutting method for a multi-core connector.

Polishing using diamond film 1 or the like at the apex is a process in which the tip of the core wire is made into a curved surface and the tips of the core wire are brought into pressure contact with the curved surfaces when connecting the connector, so in the case of a single-core connector, spherical processing is sufficient, but many For core connectors,
The cross-sectional shape must be a curved surface in a cross section perpendicular to the direction in which the core wires are arranged.

[Function] The center distance ratio between the positioning pin fitting hole of the connector body 1 and the core wire insertion hole is determined using a microscope in the same way as in the conventional manufacturing method, with the end surface of the connector body being flat. Precisely measured. After this precise measurement, the tip of the connector is cut diagonally into a pyramid or cone, and the end face of the core wire is positioned at the apex of the cone, making it possible to apply curved surface processing to the tip of the core wire using an elastic polishing machine. The tip of the core wire can be firmly held at the apex, the tip of the core wire can be finished into a predetermined curved shape, and variations in processing accuracy can be kept as small as possible.

When polished, the tips of the core wires with curved ends are exposed at the tips of pyramidal or conical connectors, so when the connectors are pressed together, all of the pressure is transferred to the small contact point of the curved ends of the core wires. Concentrate on the contact surface, that is, a point in the case of a single-core wire, or a thin linear surface in the case of a multi-core wire, and sufficiently crush the fine irregularities (1μ or less) on the contact surface of the core wires, so that the core wires are connected to each other in a so-called physical state. They can be joined in a contact state. For reference, the applicant's experimental results show that the transmission characteristics of a single core wire are 40 decibels (dB).
, for multi-core wires with two core wires, the transmission characteristics are approximately 37d.
It was B or higher. This transmission characteristic is not inferior to the transmission characteristic of pin-fitting type connectors made using conventional manufacturing methods, and the standard value is 1, which is generally required as the current state of the art.
This is a value sufficiently larger than 5 dB.

The means of the present invention can be summarized as follows based on the above description.

(a) The means of the first invention is to precisely measure the distance between the centers of the pin fitting hole and the core wire insertion hole of the connector body using a microscope, and after inserting and fixing one end of the core wire into the core wire insertion hole, the connector The tip of the main body is cut to form an inclined surface, the tip of the core wire is made to protrude from the tip of the pyramid or conical portion created by the inclined surface, and the tip of the protruding core wire is polished into a curved surface using an elastic polishing machine.

(b) The means of the second invention is that the cutting process of the tip of the connector main body in the first invention is a flat surface process.

(c) The means of the third invention is that the cutting process of the tip of the connector main body in the first invention is a curved surface process.

(d) The means of the fourth invention is directed to the first invention in which the core wire is a single core wire.

(E) The means of the fifth invention is directed to the first invention in which the core wire is a multifilamentary wire.

(f) The means of the sixth invention is that the curved surface processing by the elastic polishing machine in the fourth invention is spherical processing.

(G) The means of the seventh invention is that the curved surface processing by the elastic polishing disk in the fifth invention is a curved surface processing whose cross section perpendicular to the direction in which the core wires are arranged is arc-shaped.

[Embodiment] An embodiment in which the present invention is applied to a single-core wire connector will be described with reference to the drawings.

As a cutting method for making the tip of the connector a sloped surface, cutting using a so-called polishing machine is adopted in consideration of work efficiency and ease of controlling the polishing depth.

The connector holder that holds the connector during cutting has an arm that is tilted at a specific angle with respect to its center line, front and back, left and right, and is fixed at that position.

Attach the connector to the end of the arm.

In order to shave off one of the four corners of the tip of the connector, the arm is tilted at an angle θ in either the left or right direction, and one corner of the long side is ground at the cutting angle θ. When the grinding surface, that is, the inclined surface X.

form.

Next, the arm is tilted in either direction forward or backward by an angle θ', and one corner of the short side is ground down at a cutting angle θ', until the ground surface, that is, the inclined surface y, reaches the center C of the core line 2. Then, the arm is stopped, the arm is tilted by an angle θ' to the opposite side, and the opposite corner is ground down in the same manner to form a ground surface, that is, an inclined surface y'.

As a result, a square pyramid consisting of planes x, x', y, and y'' with the center of the core wire 2 as its apex is formed at the tip of the connector. Polishing is performed in the order of polishing, final polishing, and buffing to polish the entire tip of the core wire into a spherical surface with a finishing accuracy of 1 μ or less. Through this polishing process, the end surface of the connector becomes a spherical curved surface as shown in Figure 3. Become.

Multi-core connectors are almost the same as single-core connectors, but in the case of multi-core connectors.

Since the tips of a large number of core wires are lined up in a row and exposed at the connector end surface, the apex of the pyramid becomes a long and thin line along the arrangement of the core wires.

Further, when polished with an elastic polisher, as shown in FIG. 4, a curved surface that is long along the arrangement of the core wires and has an arcuate cross section perpendicular to the direction in which the core wires are arranged is formed.

3.3. Effects As described above, the present invention makes it possible to join the end faces of the core wires using physical contacts in a pin-fitting type connector, but the end face of the connector main body is made flat and positioning is difficult. Without changing the basic manufacturing method, which involves precisely measuring the center-to-center distance between the pin fitting hole and the core wire insertion hole using a microscope, we added a cutting process to cut the tip of the connector body diagonally after the precise measurement. , simply changing the polishing of the tip of the core wire using an elastic polishing machine to curved surface machining, which is similar to the conventional manufacturing method.
This has the great advantage of eliminating the need to apply oil or grease evenly to the tip surface of the core wire.

Improvements in this manufacturing method have also made significant progress in making the quality of products more uniform and reducing processing costs.

By using optical measurement methods and performing data analysis using a microcomputer.

It is theoretically possible to accurately measure the center-to-center distance between the locating pin fitting hole and the core wire insertion hole to the nearest 1 μm for connectors whose tip is made into an inclined surface during molding. By doing so, it is not impossible to join the core wire end faces of the pin-fitting type connector by physical contact. However, adoption of this method requires a dedicated machine as the above-mentioned center-to-center distance measuring device, which is extremely expensive, and the reliability of measurement accuracy is not very high, so it has not yet reached a practical stage. The great merit of this invention is that it enables the core wires of pin-fitting type connectors to be joined by physical contact without using such so-called high-tech technology, but by using conventional and extremely common technology. .

[Brief explanation of the drawing]

Fig. 1 is a perspective view showing a conventional example, Fig. 2 is a front view and side view showing the processing steps according to an embodiment of the present invention, and Fig. 3 is a front view showing the finished state of the connector in the embodiment of Fig. 2. , FIG. 4 shows an embodiment of a multi-core connector. In the figure, 1... connector body, 2... core wire. p... Guide pin, b... Pin fitting hole, h... Core wire insertion hole, C... Center of core wire insertion hole, X, x, y, y
'...Grinded surface. Patent applicant Fujikura Electric Cable Co., Ltd. Agent
Patent Attorney Sumihiro Ki Tamabako Figure 1 Figure 4 r Figure 2

Claims (7)

[Claims] (1) A connector body having a pair of left and right positioning pin fitting holes and a core wire insertion hole located at the midpoint between the two pin fitting holes is formed into a mold, and the connector body is flat when taken out from the mold. Using a microscope, we precisely measured the distance between the centers of the core wire insertion hole and the positioning pin fitting hole, which are open on the end surface.
For those whose center-to-center distance is within the allowable error range,
After inserting one end of the core wire into the core wire insertion hole and fixing it to the inner surface of the core wire insertion hole with adhesive, the tip of the connector body is cut to form a pyramid or conical surface with the core wire tip as the apex,
A method of manufacturing an optical fiber pin-fitting connector in which the tip of the core wire located at the apex of the tip of the connector is polished into a convex curved surface using a buff. (2) The method for manufacturing an optical fiber pin-fitting connector according to claim 1, wherein the cutting process of the tip of the connector body is a flat surface process. (3) The method for manufacturing an optical fiber pin-fitting connector according to claim 1, wherein the cutting process of the tip of the connector body is a curved surface process. (4) The method for manufacturing an optical fiber pin-fitting connector according to claim 1, wherein the core wire is a single core wire. (5) The method for manufacturing an optical fiber pin-fitting connector according to claim 1, wherein the core wire is a multicore wire. (6) The method for manufacturing an optical fiber pin-fitting connector according to claim 4, wherein the curved surface processing by the elastic polishing machine is spherical surface processing. (7) The method for manufacturing an optical fiber pin-fitting connector according to claim 5, wherein the curved surface processing by the elastic polishing machine is a curved surface processing whose cross section perpendicular to the arrangement direction of the core wires is an arc.