WO2019239567A1

WO2019239567A1 - Optical connector

Info

Publication number: WO2019239567A1
Application number: PCT/JP2018/022814
Authority: WO
Inventors: 小松　幹也; 草原　裕次; 文之千国; 達也石室
Original assignee: 株式会社日新化成
Priority date: 2018-06-14
Filing date: 2018-06-14
Publication date: 2019-12-19

Abstract

[Problem] To obtain a desired minimal bending radius with a smaller space while sufficiently considering the bending loss or fracture strength of an optical fiber and also ensuring connection consistency with an adapter. [Solution] The present invention comprises: a crimp ring 150 that is located outside a diameter-reduced part 144 of a spring push 140, and fixes a round cable 200 by inserting therebetween; and an MPO boots 160 that is located outside the crimp ring 150 and covers an end of the round cable 200. By considering a minimum bending radius R of the round cable 200, a tensile load F applied to the MPO boots 160, an inner diameter dimension d2 at the end surface of the MPO boots, and an offset amount L of the end surface of the MPO boots 160 with respect to the end surface of the crimp ring 150, the relationship between Young's modulus E of the material that forms the MPO boots 160, and the external radius dimension d1 at the end surface of the MPO boots 160 is obtained, and the material and the shape of the MPO boots 160 is determined.

Description

Optical connector

The present invention relates to an optical connector such as an MPO (Multi-fiber Push-on) connector (optical connector for an optical fiber round cable) that connects a plurality of optical fibers at once, and more specifically, an optical fiber bending space. It is about securing.

As a general round cable MPO connector, for example, there is one shown in FIG. FIG. 4A is a perspective view, and FIG. 4B is a plan view and a cross-sectional view. In these drawings, the multi-core optical fibers 505 exposed on the front side or the front side of the MPO connector 500 are aligned in an MT (Mechanically Transferable) ferrule 510, and positioning pins 512 are provided at both ends. The MT ferrule 510 is covered with an inner housing 520, and the inner housing 520 is covered with an outer housing 530.

A round cable 540 connected to the rear side or back side of the MPO connector 500 (only shown in FIG. 5A) is covered with an MPO boot 550, and the optical fiber in the round cable 540 is the inner housing 520, MT ferrule. 510 is exposed as a multi-core optical fiber 505. The inner housing 520 is exposed from the skirt portion 532 on the round cable 540 side of the outer housing 530, and a spring push 560 is provided between the outer housing 530 and the MPO boot 550. The round cable 540 is fixed by the spring push 560.

The spring push 560 is reduced in diameter toward the rear side, and becomes a reduced diameter portion 562. A crimp ring 570 is provided outside the reduced diameter portion 562, and a ring 572 is provided outside the crimp ring 570. The crimp ring 570 is configured such that the Kevlar of the round cable 540 is sandwiched between the reduced diameter portion 562 of the spring push 560. Further, the ring 572 is for preventing the round cable 540 from being displaced by caulking the covering of the round cable 540. The overall length of the MPO connector 500 is 66 mm, and the length of the MPO boot 550 is 40 mm.

When attaching the MPO connector 500 to the MPO adapter 600, the MPO connector 500 is pushed in the direction of arrow F with the spring push 560, or the MPO connector 500 is pushed by holding the MPO boot 550 with a finger. On the contrary, when the MPO connector 500 is detached from the MPO adapter 600, the MPO connector 500 is detached by picking the outer housing 530 with a finger and pulling it in the direction opposite to the arrow F.

By the way, in order to improve the wiring flexibility of the optical fiber, an optical fiber having an allowable bending radius R of 15 mm (bending R15) is commercially available. However, an MPO connector for effectively utilizing this characteristic is required. . However, in the above-described general round cable MPO connector, since the boot shape is long and the rigidity is high, it is difficult to achieve the bending R15, and a space-saving MPO connector capable of achieving the bending R15 is desired. .
Further, as a background art focusing on this point, for example, there is an “optical connector” described in Patent Document 1 below. This is because the ferrule to which one end of the optical fiber is fixed is prevented from coming off from the housing and is extended from the rear end of the housing with the tip of the flexible protective boot engaged. The optical fiber tape core is formed by partially enclosing a portion of the other end side of the optical fiber and positioning an engaging portion between the stopper and the tip of the protective boot in the housing. The bending radius of the optical fiber ribbon considering the bending loss and breakage of the wire is ensured in a small space.

JP 2003-215401 A

However, the optical connector described in Patent Document 1 described above relates to an MPO connector for a tape core wire, and is excellent in space saving but inferior in durability as compared with an MPO connector for a round cable. In addition, in the case of a round cable, it is necessary to consider the bending loss and breaking strength of the optical fiber even if the bending R15 is ensured in a small space. Also, connection consistency between the MPO connector and the MPO adapter is important.

The present invention focuses on the above points, and its purpose is to sufficiently consider the bending loss and breaking strength of the optical fiber, and to ensure the connection matching with the adapter, and to achieve the desired minimum bending in a smaller space. To get the radius.

The present invention includes a crimp ring that is positioned outside a reduced diameter portion of a spring push and is fixed with a cable interposed therebetween, and a boot that is positioned outside the crimp ring and covers an end portion of the cable. An optical connector having a minimum radius of curvature R of the cable, a tensile load F applied to the boot, an outer diameter d1, an inner diameter d2, and an offset L of the boot end surface with respect to the crimp ring end surface, The boot is formed of a material having a Young's modulus E determined in consideration of the above.

In another aspect of the invention, there is provided a crimp ring that is positioned outside the reduced diameter portion of the spring push and is fixed with a cable interposed therebetween, and a boot that is positioned outside the crimp ring and covers an end portion of the cable. An optical connector provided with a Young's modulus E of the material forming the boot, a minimum radius of curvature R of the cable, a tensile load F applied to the boot, an inner diameter dimension d2 of the end face of the boot, and the crimp ring end face with respect to the end face. The boot is formed so as to have an outer diameter dimension d1 determined in consideration of the offset amount L of the boot end face.

Still another invention is a crimp ring that is positioned outside a reduced diameter portion of a spring push and is fixed with a cable interposed therebetween, and a boot that is positioned outside the crimp ring and covers an end of the cable. In consideration of the minimum radius of curvature R of the cable, the tensile load F applied to the boot, the inner diameter dimension d2 of the end face of the boot, and the offset L of the end face of the crimp ring relative to the end face of the crimp ring. Then, the relationship between the Young's modulus E of the material forming the boot and the outer diameter d1 at the end face of the boot is obtained, and the material and shape of the boot are determined using this relationship. .

According to one of the main forms, the relationship between the Young's modulus E and the outer diameter d1 of the boot is

It is represented by.
According to still another aspect, the cable is a cable that can be bent with a minimum radius of curvature of 15 mm. According to still another aspect, the tensile load F applied to the boot is a standard value that defines the durability of the tensile load of the boot or a value lower than that, more specifically, The standard value is 3.3 kgf. In another embodiment, the inner diameter d2 at the end face of the boot is the outer diameter of the cable fixed by the crimp ring, and more specifically, the inner diameter d2 is 3 mm. It is characterized by. The above and other objects, features and advantages of the present invention will become apparent from the following detailed description and the accompanying drawings.

According to the present invention, the Young's modulus material or outer dimensions determined in consideration of the minimum radius of curvature of the cable, the tensile load applied to the boot, the inner diameter of the boot end face, and the offset of the boot end face with respect to the crimp ring end face. Since the boot is formed in the shape of the above, it is possible to obtain the desired minimum bending radius in a smaller space while ensuring the connection consistency with the adapter and sufficiently considering the bending loss and breaking strength of the optical fiber. Can do.

It is a figure which shows the whole MPO connector in Example 1 of this invention. (A) is a perspective view, (B) is a plane when (A) is viewed from the direction of arrow F1, and a part is a cross section viewed along the # 1- # 1 line in the direction of the arrow. (C) is a plan and cross-sectional view showing another embodiment. It is a figure which shows the mode of the cable attachment in the said Example. It is a figure which shows the example of a dimension of each part in the said Example. (A) shows a state where the cable is bent, and (B) is a graph showing the relationship between the Young's modulus and the outer diameter of the material of the MPO boot in the example of FIG. It is a figure which shows an example of the conventional MPO connector.

Hereinafter, the best mode for carrying out the present invention will be described in detail based on examples.

FIG. 1 shows an MPO connector according to the present embodiment. FIG. 2A shows the appearance, and FIG. 2B shows a plane viewed from the arrow F1 in FIG. Also, in the same figure (B), the upper part from the center shows the internal structure viewed in the direction of the arrow along the # 1- # 1 line of the same figure (A), and the lower part shows the external appearance. In these drawings, the multi-core optical fibers 105 exposed on the front side of the MPO connector 100 are aligned in an MT (Mechanically Transferable) ferrule 110, and positioning pins 112 are provided at both ends. The MT ferrule 110 is covered with an inner housing 120, and the inner housing 120 is further covered with an outer housing 130. A spring push 140 is provided behind the outer housing 130. These structures and shapes are the same as those of the MPO connector 500 of the background art described above, and therefore, connection consistency is ensured with respect to the conventional MPO adapter.

Next, a spring 132 is provided between the inner housing 120 and the outer housing 130, and the outer housing 130 is slid against the urging force of the spring 132, thereby preventing the MPO adapter (see FIG. 5). The engagement is released and the MPO connector 100 can be removed. Further, a spring 142 is provided between the inner housing 120 and the spring push 140, and the MPO connector 100 is engaged with the MPO adapter by pushing the spring push 140 against the urging force of the spring 142. It comes to match.

The rear side (right side of the drawing) of the spring push 140 is a reduced diameter portion 144. The reduced diameter portion 144 is provided with a crimp ring 150, and the outer side thereof is provided with an MPO boot 160. Yes. In the MPO connector 500 of the background art shown in FIG. 5, the crimp ring 570 and the ring 572 are provided. However, in this embodiment, only the crimp ring 150 is provided, which is connected to the crimp ring 570 and the ring 572. I also use it.

Comparing the MPO connector 100 of this embodiment with the MPO connector 500 of FIG. 5 described above, the inner housing 120, the spring push 140, the crimp ring 150, and the MPO boot 160 are all shortened and designed to be compact. It is composed of the smallest shape. Specifically, the overall length of the MPO connector 500 shown in FIG. 5 is 66 mm, whereas the overall length of the MPO connector 100 of this embodiment is 32 mm.

Next, the connection of the round cable 200 will be described with reference to FIG. As shown in FIG. 1A, the round cable 200 has a Kevlar 202 on the outside of the above-described multi-core optical fiber 105, and further a coating 204 is formed on the outside thereof. Among these, the multi-core optical fiber 105 passes through the MPO boot 160, the crimp ring 150, the spring push 140, and the inner housing 120, and is arranged in the MT ferrule 110 as described above. Next, the Kevlar 202 is sandwiched between the reduced diameter portion 144 of the spring push 140 and the large diameter portion of the crimp ring 150 and fixed by crimping the crimp ring 150. The entire cable including the sheath 204 passes through the MPO boot 160 and is fixed by caulking with a small diameter portion on the entrance side of the crimp ring 150.

Next, conditions for setting the total bending length when the round cable 200 is bent at “bending R15” to 47.5 mm or less as shown in FIG. 3 will be described. In order to follow the bending of R15 of the round cable 200, first, a cable that bends corresponding to the bending R15 is used. Specifically, as shown in FIG. 4A, when a round cable 200 having an outer diameter of 3.0 mm is bent to R15, the length of the arc at the center of the cable is 15 × 2 × π / 4. On the other hand, the lengths of the inner and outer arcs are (15 ± 1.5) × 2 × π / 4, and the ratio is 100 ± 10%. Therefore, the expansion / contraction rate of the cable is required to be a numerical value that is infinitely close to 90% or more and 110% or less (90% ≦ expansion / contraction rate ≦ 110%) when a tensile load F as a load is applied. That is, the bending radius Rin of the inner arc is −10% and the bending radius Rin of the outer arc is + 10% with respect to the bending radius R = 15 mm of the central arc, and Rout = 16. 5 mm.

Next, the design of the MPO boot 160 is important, and it is important to optimize the rigidity of the MPO boot 160 to ensure a bending total length of 47.5 mm or less. Here, since the round cable 200 is bent from the end face PA of the crimp ring 150 which is the root, attention is paid to this point. When the Young's modulus (elastic coefficient) of the MPO boot 160 is E, the secondary moment of section is I, and the bending moment is M, the radius of curvature R of the round cable 200 is E × I as shown in the following equation (1). Proportional to the value of. For this reason, if a material and a shape with a high elastic modulus E are selected, the radius of curvature R becomes high and the bending R15 cannot be achieved.

On the other hand, when the outer diameter dimension at the end face PB of the MPO boot 160 is d1 and the inner diameter dimension is d2, the cylindrical sectional secondary moment I is expressed by the following equation (2).

Further, when the tension load applied to the MPO boot 160 when the round cable 200 is bent is F and the offset amount corresponding to the distance from the end face PA of the crimp ring 150 to the end face PB of the MPO boot 160 is L, the end face of the MPO boot 160 The bending moment M applied to PB is expressed by the following equation (3).

When the outer diameter d1 of the MPO boot 160 is obtained from the above formulas 1 to 3, the following formula 4 is obtained. This condition is a relationship that the outer diameter dimension d1 of the MPO boot 160 and the Young's modulus E of the material to be used should be satisfied.

FIG. 4B shows the relationship between the Young's modulus E of the material and the boot outer diameter d1 based on the equation (4). In addition,
a, radius of curvature R: 15 mm
b, tensile load F: 2kgf
c, Offset amount L: 2.8 mm
d, MPO boot inner diameter d2: 3mm
It was. In addition, the value of the tensile load of b mentioned above has an item that the durability of the tensile load of the MPO boot 160 is “3.3 kgf or more” in the MPO standard (Telcordia). It is a representative value. In addition, the value of the inner diameter d2 of the MPO boot 160 of the above d is a value in accordance with the outer diameter of a general round cable being “3 mm”. According to the graph of FIG. 6, if the MPO boot 160 is manufactured using a material having a Young's modulus of 260 MPa, for example, the optimum boot outer diameter d1 is 4.36 mm.

As described above, according to the present embodiment, the round cable 200 of the bending R15 is used,
a, the shape of the spring push 140 and the crimp ring 150 of the MPO connector 100,
b, Young's modulus E of the material used for the MPO boot 160,
c, the outer diameter d1 and the inner diameter d2, of the MPO boot 160
d, the offset amount L of the MPO boot 160 with respect to the crimp ring 150,
Therefore, a desired minimum bending radius can be obtained with less space. Specifically, when the MPO connector 100 having a minimum length of about 32 mm as an IEC standard product is used, the distance to obtain the R15 bending radius can be 47.5 mm or less. Further, there is no bending loss or breaking strength of the optical fiber, and connection consistency with the MPO adapter can be ensured. For this reason, the distance from the back panel which mounts an MPO connector and an MPO adapter to the inside of a door can be shortened, and a big space effect is acquired.

Next, Embodiment 2 of the present invention will be described with reference to FIG. The MPO connector 101 of this embodiment is similar to the above-described embodiment on the MT ferrule 110 side of the inner housing 121 as compared to the above-described embodiment of FIGS. 1A and 1B, but the opposite side 121B. Is slightly longer and is similar to the inner housing 520 of the MPO connector 500 of the background art shown in FIG. For this reason, the spring push 141 of the present embodiment is also as shown in the background art of FIG. 5, but is provided with a reduced diameter portion 144 as in the embodiment of FIGS. 1 (A) and 1 (B). .

The overall length of the MPO connector 101 of this embodiment is 34.5 mm, which is shorter than the overall length of 66 mm of the MPO connector 500 shown in FIG. 5, but the MPO of the embodiment shown in FIGS. The total length of the connector 100 is longer than 32 mm. However, according to this example,
a, Since the shape and dimensions on the ferrule side are the same as the conventional one, connection consistency with the MPO adapter is ensured.
b, since the shape from the reduced diameter portion 144 of the spring push 141 to the crimp ring 150 and the MPO boot 160 is the same as that of the above-described embodiment, the distance until the R15 bending radius is obtained is somewhat longer, but is similarly good. Space effect can be obtained.

In addition, this invention is not limited to the Example mentioned above, A various change can be added in the range which does not deviate from the summary of this invention. For example, the following are also included.
(1) The shapes and dimensions shown in the above embodiments are examples, and may be appropriately changed as necessary.
(2) The numerical values shown in the above-described embodiments are also examples, and are not limited thereto.
(3) The above-described embodiment is a suitable example of an MPO connector that connects a plurality of optical fibers at once, but can be applied to various optical connectors.

According to the present invention, the Young's modulus material or outer dimensions determined in consideration of the minimum radius of curvature of the cable, the tensile load applied to the boot, the inner diameter of the boot end face, and the offset of the boot end face with respect to the crimp ring end face. Since the boot is formed in the shape of the above, it is possible to obtain the desired minimum bending radius in a smaller space while ensuring the connection consistency with the adapter and sufficiently considering the bending loss and breaking strength of the optical fiber. It is suitable for MPO connectors and the like.

100, 101: Connector 105: Multi-core optical fiber 110: Ferrule 112: Pin 120, 121: Inner housing 130: Outer housing 132: Spring 140, 141: Spring push 142: Spring 144: Reduced diameter portion 150: Crimp ring 160: MPO boot 200: Round cable 202: Kevlar 204: Cover 500: Connector 505: Multi-core optical fiber 510: Ferrule 512: Pin 520: Inner housing 530: Outer housing 532: Skirt portion 540: Round cable 550: Boot 560: Spring push 562: Reduced diameter portion 570: Crimp ring 572: Ring 600: MPO adapter
d1: Boot outer diameter d2: Boot inner diameter PA, PB: End face

Claims

An optical connector that is located outside the reduced diameter portion of the spring push and that has a crimp ring that is fixed with the cable in between, and a boot that is located outside the crimp ring and covers the end of the cable. There,
Young determined by taking into consideration the minimum radius of curvature R of the cable, the tensile load F applied to the boot, the outer diameter d1, the inner diameter d2, and the offset L of the boot end face with respect to the crimp ring end face. An optical connector, wherein the boot is formed of a material having a rate E.
An optical connector that is located outside the reduced diameter portion of the spring push and that has a crimp ring that is fixed with the cable in between, and a boot that is located outside the crimp ring and covers the end of the cable. There,
Young's modulus E of the material forming the boot, minimum radius of curvature R of the cable, tensile load F applied to the boot, inner diameter dimension d2 of the boot end surface, offset amount L of the boot end surface with respect to the crimp ring end surface, An optical connector, wherein the boot is formed so as to have an outer diameter d1 determined in consideration.
An optical connector that is located outside the reduced diameter portion of the spring push and that has a crimp ring that is fixed with the cable in between, and a boot that is located outside the crimp ring and covers the end of the cable. There,
Considering the minimum radius of curvature R of the cable, the tensile load F applied to the boot, the inner diameter d2 of the end face of the boot, and the offset L of the end face of the boot relative to the end face of the crimp ring, the material of the material forming the boot An optical connector characterized in that a relationship between a Young's modulus E and an outer diameter d1 at an end face of the boot is obtained, and the material and shape of the boot are determined using this relationship.
The relationship between the Young's modulus E and the outer diameter d1 of the boot is

The optical connector according to claim 3, wherein
5. The optical connector according to claim 1, wherein the cable is a cable that can be bent with a minimum curvature radius of 15 mm.
6. The optical connector according to claim 1, wherein the tensile load F applied to the boot is set to a standard value that defines the durability of the tensile load of the boot or a value lower than the standard value. .
The optical connector according to claim 6, wherein the standard value is 3.3 kgf.
The optical connector according to any one of claims 1 to 7, wherein an inner diameter d2 of the end face of the boot is an outer diameter of a cable fixed by the crimp ring.
The optical connector according to claim 8, wherein the inner diameter d2 of the end face of the boot is 3 mm.