JP7542987B2 - Optical connector system and plug - Google Patents

Description

This disclosure relates to optical connector systems and plugs.

Patent document 1 describes a structure for fitting a plug into a receptacle.

JP 2017-45597 A

When a plug is inserted into a receptacle, if there is a large gap between the inner wall surface of the receptacle and the outer surface of the plug, the plug may rattle relative to the receptacle, resulting in large optical signal loss (connection loss).

The purpose of the present invention is to reduce rattling between the receptacle and the plug and to reduce loss of optical signals.

The first main invention for achieving the above-mentioned object is a connector system comprising: a receptacle having a plug accommodating portion with a cylindrical inner wall surface and a groove on the inner wall surface; a plug that is inserted into the plug accommodating portion and has a tip portion on the side that is inserted into the receptacle and a main body portion, wherein the tip portion has a cylindrical outer peripheral surface facing the inner wall surface, and the main body portion has two parallel planar portions, two cylindrical portions disposed between the two planar portions and facing the inner wall surface, and a protrusion portion that fits into the groove.
The second main invention for achieving the above object is a plug to be inserted into a plug accommodating portion of a receptacle having a cylindrical inner wall surface, the plug comprising: a tip portion on the side to be inserted into the receptacle; and a main body portion, the tip portion having a cylindrical outer peripheral surface facing the inner wall surface, the main body portion having a pair of parallel flat portions, a pair of cylindrical portions disposed between the pair of flat portions and facing the inner wall surface, and a protrusion portion that fits into a groove formed in the inner wall surface.

Other features of the present invention will become clear from the following description and drawings.

The present invention can reduce rattling between the receptacle and the plug, and reduce loss of optical signals.

1A and 1B are perspective views of an optical connector system 1 of a reference example. FIG. 2 is a perspective view of the optical connector in a connected state. 3A and 3B are cross-sectional views of the optical connector system 1. FIG. Fig. 4A is a perspective view of the plug 20. Fig. 4B is a perspective view of the plug 20 with the coupling 30 separated. 5A and 5B are explanatory diagrams for explaining the positional relationship between the elastic piece 24 and the coupling 30. FIG. 6A to 6E are explanatory diagrams showing how receptacle 10 and plug 20 are connected. 7A to 7E are explanatory diagrams showing how the connection between the receptacle 10 and the plug 20 is released. Fig. 8A is an explanatory diagram of the deformation of the elastic piece 24 when the fitting projection 24A is released from the fitting hole 121. Fig. 8B is an explanatory diagram of the deformation of the elastic piece 24 of the comparative example. Fig. 9A is an explanatory diagram of a first comparative example, Fig. 9B is an explanatory diagram of a second comparative example, and Fig. 9C is an explanatory diagram of the present embodiment. 10A and 10B are perspective views of the optical connector system 2 of this embodiment. FIG. 11 is a perspective view of the receptacle 10 of the present embodiment. Fig. 12A is a perspective view of the plug 20 of this embodiment. Fig. 12B is a perspective view of the plug 20 of this embodiment with the coupling 30 separated. 13A and 13B are explanatory diagrams of modified examples of the arrangement of the protrusions 234. FIG. 14A and 14B are explanatory diagrams of modified examples of the plug 20. FIG.

At least the following points become clear from the description and drawings described below.

A connector system comprising: a receptacle having a plug accommodating section with a cylindrical inner wall surface and a groove on the inner wall surface; a plug to be inserted into the plug accommodating section, the plug having a tip portion on the side to be inserted into the receptacle and a main body portion, the tip portion having a cylindrical outer circumferential surface facing the inner wall surface, the main body portion having two parallel flat portions, two cylindrical portions disposed between the two flat portions and facing the inner wall surface, and a protrusion portion that fits into the groove. Such an optical connector system can suppress rattling between the receptacle and the plug, and suppress loss of optical signals.

It is desirable that the protrusions protrude in a direction perpendicular to the direction in which the pair of flat surfaces face each other. This makes it possible to suppress rattling between the receptacle and the plug in a direction perpendicular to the flat surfaces.

It is desirable that the protrusions extend from the planar portion. The protrusions can be realized with a simple configuration.

It is desirable that the protrusion have a surface parallel to the flat surface and a surface perpendicular to the flat surface. This makes it possible to suppress rattling between the receptacle and the plug in two directions (the direction perpendicular to the flat surface and the direction parallel to the flat surface).

It is preferable that the protrusion is disposed between the flat surface and the cylindrical surface. This makes it possible to suppress the gap in the direction perpendicular to the flat surface.

It is desirable for the number of protrusions to be an even number. This allows the protrusions to be arranged symmetrically while still allowing the faces of one protrusion to be parallel to the faces of another protrusion.

It is desirable that the protrusions are provided on each of the two flat surfaces. This allows the gap between the receptacle and the plug to be narrowed in the direction perpendicular to the flat surfaces on both flat surfaces.

It is desirable that a waterproofing material be arranged on the outer peripheral surface of the end portion. This makes it possible to waterproof the inside of the optical connector system.

the plug accommodating portion of the receptacle has a recess that accommodates the end portion of the plug,
It is preferable that the groove is located closer to the plug than the recess, thereby making it possible to prevent water from entering through the groove.

It is desirable that the end face of the protrusion facing the receptacle is inclined. This makes it easier to insert the plug into the receptacle.

A plug to be inserted into a plug receiving portion of a receptacle having a cylindrical inner wall surface, the plug comprising a tip portion on the side to be inserted into the receptacle and a main body portion, the tip portion having a cylindrical outer circumferential surface facing the inner wall surface, the main body portion having a pair of parallel flat portions, a pair of cylindrical portions disposed between the pair of flat portions facing the inner wall surface, and a protrusion portion that fits into a groove formed in the inner wall surface. Such a plug can suppress rattling relative to the receptacle and suppress loss of optical signals.

== ...
<Optical connector system 1>
1A and 1B are perspective views of an optical connector system 1 according to a reference example. Fig. 2 is a perspective view of an optical connector in a connected state. Figs. 3A and 3B are cross-sectional views of the optical connector system 1.

The optical connector system 1 has a receptacle 10 and a plug 20. The receptacle 10 may be called the "receptacle-side optical connector" and the plug 20 may be called the "plug-side optical connector." The receptacle 10 may also be called the "first optical connector" and the plug 20 may also be called the "second optical connector." Each of the receptacle 10 and the plug 20 may also simply be called an "optical connector."

In the following description, each direction is defined as shown in Figures 1A and 1B. That is, the direction in which the connector is attached and detached is the "front-rear direction", the side of the mating optical connector is the "front", and the opposite side is the "rear". The insertion direction in which the plug 20 is inserted into the receptacle 10 is parallel to the front-rear direction. The direction in which the pair of fitting holes 121 or the pair of fitting protrusions 24A are lined up is the "left-right direction", the right side when viewed from the rear to the front is the "right", and the opposite side is the "left". The direction perpendicular to the front-rear direction and the left-right direction is the "up-down direction". The side of the key groove 126 or the key protrusion 233 is the "up" and the opposite side is the "down".

<Receptacle 10>
The receptacle 10 is an optical connector for connecting the plug 20. The receptacle 10 has a fitting hole 121. The fitting hole 121 will be described later.

As shown in Figures 3A and 3B, the receptacle 10 has a ferrule 11, a housing 12, a spring 13, and a spring retainer 14.

The ferrule 11 is a member that holds an optical fiber. The ferrule 11 is an MT type optical connector (an F12 type optical connector defined in JIS C5981) that holds multiple optical fibers. A pair of guide pins 11A protrude from the end face of the ferrule 11 of the receptacle 10. The ferrule 11 (and the guide pins 11A) are disposed rearward of the front edge of the receptacle 10 (more specifically, the housing 12). The receptacle 10 has two ferrules 11 arranged vertically. However, the number of ferrules 11 may be one, or three or more. Also, multiple ferrules 11 may be arranged horizontally instead of vertically.

The housing 12 is a member that accommodates the ferrule 11 so that it can retract. The housing 12 is configured in a cylindrical shape. The housing 12 is formed with a ferrule accommodating section that accommodates the ferrule 11. A protrusion is formed on the inner wall surface of the ferrule accommodating section, and the flange of the ferrule 11 comes into contact with this protrusion to prevent the ferrule 11 from slipping out from the front. The front side of the housing 12 is open, and the plug 20 is inserted through this opening. A pair of fitting holes 121 are formed on the left and right side surfaces of the front part of the housing 12. The housing 12 has the fitting hole 121, a plug accommodating section 122, a key groove 126, and a guide groove 127.

The mating hole 121 is a hole (engagement hole) for fitting the mating protrusion 24A of the plug 20. The plug 20 is connected to the receptacle 10 by fitting the mating protrusion 24A of the plug 20 into the mating hole 121. The front edge of the mating hole 121 is the portion where the mating protrusion 24A of the plug 20 engages, and serves as a mechanical reference surface on the receptacle 10 side.

The plug accommodating section 122 is a section that accommodates the plug 20. The plug accommodating section 122 is formed by the internal space at the front of the cylindrical housing 12. The plug accommodating section 122 has a recess 123. The recess 123 is a concave section that accommodates the tip 231 (described later) of the plug 20. The recess 123 is a concave section formed to surround the ferrule accommodating section. The inner wall surface of the recess 123 becomes a contact section that comes into contact with the O-ring 231A of the plug 20. When the receptacle 10 and the plug 20 are connected, the inner wall surface of the recess 123 comes into contact with the O-ring 231A of the plug 20, thereby waterproofing the inside of the optical connector system 1 (particularly the connection between the ferrules).

The key groove 126 (see FIG. 1B) is a groove-like portion formed on the inner wall surface of the cylindrical housing 12, and is formed to fit the key protrusion 233 of the plug 20. The key groove 126 is formed along the front-to-rear direction, and is formed on the upper side of the inner wall surface of the housing 12. By matching the key protrusion 233 of the plug 20 with the key groove 126, the receptacle 10 and the plug 20 are aligned in the circumferential direction (the rotational direction about the front-to-rear direction).

The guide groove 127 (see FIG. 1B) is a groove-like portion formed on the inner wall surface of the cylindrical housing 12, and is formed to fit the elastic piece 24 of the plug 20. The guide groove 127 is formed along the front-rear direction, and is formed on both the left and right sides of the inner wall surface of the housing 12. The fitting hole 121 is disposed in the guide groove 127. This allows the guide groove 127 to guide the fitting protrusion 24A of the elastic piece 24 into the fitting hole 121. The guide groove 127 guides the fitting protrusion 24A of the elastic piece 24 into the fitting hole 121, making it easier to fit the fitting hole 121 of the receptacle 10 and the fitting protrusion 24A of the plug 20.

The spring 13 is a member for pressing the ferrule 11 forward. The spring bearing 14 is a member fixed to the housing 12 and is a member that contacts the rear end of the spring 13. The spring 13 is disposed in a compressed state between the ferrule 11 and the spring bearing 14, and presses the ferrule 11 forward. The spring 13 and the spring bearing 14 form a floating mechanism that presses the ferrule 11 forward so that it can be moved backward.

<Plug 20>
The plug 20 is an optical connector that is connected to the receptacle 10. The plug 20 is inserted into the receptacle 10 and has an elastic piece 24 having a fitting protrusion 24A that fits into a fitting hole 121. The plug 20 also holds a coupling 30. The elastic piece 24 (and the fitting protrusion 24A) and the coupling 30 will be described later.

As shown in Figures 3A and 3B, the plug 20 has a ferrule 21, a housing 22, a spring 27, and a spring retainer 28.

The ferrule 21 is a member that holds an optical fiber. The ferrule 21 of the plug 20 is similar to the ferrule 11 of the receptacle 10, but does not have a guide pin 11A, and a guide hole for inserting the guide pin 11A opens at the end face of the ferrule. The ferrule 21 is disposed rearward of the front edge of the plug 20 (more specifically, the housing 22). The plug 20 has two ferrules 21 arranged vertically. However, the number of ferrules 21 may be one, or three or more. Also, multiple ferrules 21 may be arranged horizontally instead of vertically.

The housing 22 is a member that accommodates the ferrule 21 so that it can retract. The housing 22 has a housing body 23 and an elastic piece 24. The housing body 23 is a cylindrically configured portion, and is the portion of the housing 22 excluding the elastic piece 24. A ferrule accommodating portion that accommodates the ferrule 21 is formed in the housing body 23. A protrusion formed in the ferrule accommodating portion prevents the ferrule 21 from slipping out from the front. The front side of the housing body 23 is open, and the ferrule 11 of the receptacle 10 is inserted through this opening. The housing body 23 has a tip portion 231 and a key protrusion 233.

The tip 231 is a cylindrical part on the front side of the housing 22. The tip 231 protrudes forward from the ferrule 21 and has the function of protecting the ferrule 21. When the receptacle 10 and the plug 20 are connected, the tip 231 is accommodated in the recess 123 of the receptacle 10. An O-ring 231A is arranged on the outer circumferential surface of the tip 231. The O-ring 231A is a member that waterproofs the inside of the optical connector system 1 (particularly the connection part between the ferrules). When the receptacle 10 and the plug 20 are connected, the O-ring 231A comes into contact with the inner wall surface (contact part) of the recess 123 of the receptacle 10 and is compressed in the radial direction. The part of the housing main body 23 rearward of the tip 231 (the part where the elastic piece 24 is provided) is sometimes called the main body part 232.

The key projection 233 is a protruding portion formed on the outer peripheral surface of the cylindrical housing body 23, and is formed to fit into the key groove 126 of the receptacle 10. The key projection 233 is formed along the front-to-rear direction, and is formed on the upper side of the outer peripheral surface of the housing body 23. By matching the key projection 233 with the key groove 126 of the receptacle 10, the plug 20 is aligned in the circumferential direction (the rotation direction about the front-to-rear direction as an axis) with respect to the receptacle 10. In other words, the key projection 233 and the key groove 126 of the receptacle 10 form an alignment portion that aligns the plug 20 with the receptacle 10. Note that the key projection may be formed on the receptacle 10, and the key groove may be formed on the plug 20.

The spring 27 is a member for pressing the ferrule 21 forward. The spring receiver 28 is a member that is fixed to the housing 22 and is a member that contacts the rear end of the spring 27. The spring 27 is disposed in a compressed state between the ferrule 21 and the spring receiver 28, and presses the ferrule 21 forward. The spring 27 and the spring receiver 28 form a floating mechanism that presses the ferrule 21 forward so that it can be moved backward.

<Elastic piece 24 of plug 20 and coupling 30>
Fig. 4A is a perspective view of the plug 20. Fig. 4B is a perspective view of the plug 20 in a state where the coupling 30 is separated. Figs. 5A and 5B are explanatory views for explaining the positional relationship between the elastic piece 24 and the coupling 30.

The housing 22 of this reference example has an elastic piece 24. The elastic piece 24 is an elastically deformable portion. A gap 25 is formed between the elastic piece 24 and the housing body 23. As a result, the elastic piece 24 is elastically deformable in the radial direction (direction perpendicular to the insertion direction in which the plug 20 is inserted into the receptacle 10) when the plug 20 is inserted into the receptacle 10. The elastic piece 24 is a cantilever-shaped portion along the front-rear direction. The base end of the elastic piece 24 (the end of the elastic piece 24 fixed to the housing body 23) is located forward of the free end. In other words, the elastic piece 24 is shaped to extend from the base end on the front side toward the rear side. When the plug 20 is inserted into the receptacle 10, the elastic piece 24 is disposed inside the cylindrical housing 22 of the receptacle 10.
In this embodiment, a pair of elastic pieces 24 are disposed on both the left and right side surfaces of the housing main body 23. However, the number of elastic pieces 24 is not limited to two. Furthermore, the arrangement of the elastic pieces 24 may be on the outer circumferential surface of the housing 22, and is not limited to the left and right side surfaces.

The elastic piece 24 has a mating protrusion 24A. The mating protrusion 24A is a protrusion that fits into the mating hole 121 of the receptacle 10. The plug 20 is connected to the receptacle 10 by fitting the mating protrusion 24A into the mating hole 121 of the receptacle 10. The rear edge of the mating protrusion 24A is a portion (step portion) that engages with the mating hole 121 of the receptacle 10, and serves as a mechanical reference surface for the plug 20. Since the mating protrusion 24A is disposed on the elastic piece 24, when the elastic piece 24 elastically deforms, the mating protrusion 24A is displaced. The mating protrusion 24A is disposed on the outer surface of the elastic piece 24 and protrudes outward. When the plug 20 is inserted into the receptacle 10, the mating protrusion 24A fits from the inside to the outside of the mating hole 121 of the receptacle 10.

As shown in Figures 3A and 3B, the free end of the elastic piece 24 (the end opposite the base end) is held by a holding portion 31 (described below) of the coupling 30. This prevents the elastic piece 24 from being accidentally elastically deformed, and prevents the fitting protrusion 24A from coming out of the fitting hole 121.

As shown in FIG. 4B, a protrusion 24B is provided on the free end of the elastic piece 24 (the end opposite the base end). The protrusion 24B is a portion that protrudes outward from the side of the elastic piece 24. The protrusion 24B is a portion that comes into contact with the release mechanism 32 of the coupling 30 (see FIG. 4B). When the protrusion 24B comes into contact with the release mechanism 32 of the coupling 30, the free end of the elastic piece 24 is displaced radially toward the housing main body 23, and the engagement between the fitting hole 121 and the fitting protrusion 24A is released (the fitting protrusion 24A comes out of the fitting hole 121).

The elastic piece 24 has a first portion 241 and a second portion 242 (see FIG. 3A). The first portion 241 is the portion between the base end and the engaging protrusion 24A. The second portion 242 is the portion between the engaging protrusion 24A and the free end (protruding portion 24B). In other words, the portion in front of the engaging protrusion 24A is the first portion 241, and the portion behind the engaging protrusion 24A is the second portion 242. When the elastic piece 24 elastically deforms, mainly the first portion 241 elastically deforms and the second portion 242 is displaced.

3A and 3B, the second portion 242 is thicker than the first portion 241. Therefore, the second portion 242 is less likely to elastically deform than the first portion 241. If the second portion 242 were to have a shape that was more likely to elastically deform, even if the free end (protrusion 24B) of the elastic piece 24 were to be displaced toward the housing main body 23, the fitting protrusion 24A would be less likely to be displaced, and the fitting between the fitting hole 121 and the fitting protrusion 24A would be less likely to be released (see FIG. 8B, described below). However, as long as the fitting between the fitting hole 121 and the fitting protrusion 24A can be released, the second portion 242 does not need to be thicker than the first portion 241.

The second part 242 has a tapered portion 242A. The tapered portion 242A is an inclined surface provided on the surface facing the housing main body 23. A gap 25 is formed between the elastic piece 24 (second part 242) and the housing main body 23, and the tapered portion 242A is formed so that the gap 25 becomes larger toward the free end (protrusion 24B). This makes it possible to largely displace the free end (protrusion 24B) of the elastic piece 24 toward the housing main body 23, as described below (see FIG. 8A). However, if the engagement between the engagement hole 121 and the engagement protrusion 24A can be released, the tapered portion 242A does not have to be formed in the second part 242.

The coupling 30 is a member that can move relative to the housing 22 toward the side opposite the receptacle 10. In other words, the coupling is a member that can retract relative to the plug 20 (housing 22). The coupling 30 is held by the plug 20. The coupling 30 is a cylindrical member that is disposed on the outside of the housing 22. The coupling 30 has the function of maintaining the engagement between the engagement hole 121 and the engagement protrusion 24A, and the function of releasing the engagement between the engagement hole 121 and the engagement protrusion 24A. The coupling 30 has a holding portion 31 and a release mechanism 32.

The holding portion 31 is a portion that holds the end (free end) of the elastic piece 24. By holding the free end of the elastic piece 24 with the holding portion 31, the displacement of the free end of the elastic piece 24 is suppressed, and the engagement between the fitting hole 121 and the fitting protrusion 24A is maintained. When the holding portion 31 holds the free end of the elastic piece 24, the displacement of the free end of the elastic piece 24 is suppressed compared to a state in which the free end of the elastic piece 24 is not held. In other words, when the holding portion 31 holds the free end of the elastic piece 24, the free end of the elastic piece 24 may be allowed to displace slightly. The holding portion 31 is disposed on the inner wall surface of the cylindrical coupling 30. In this reference example, the holding portions 31 are disposed so as to correspond to each of the elastic pieces 24, and are disposed on both the left and right sides of the inner wall surface of the coupling 30.

The holding portion 31 of this reference example includes a pressing portion 31A and a connecting portion 31B (see Figs. 3A, 3B, 5A, and 5B). The pressing portion 31A is a portion that presses the free end of the elastic piece 24 from the inside (the side of the housing body 23) and is a plate-like portion parallel to the front-rear direction. As shown in Figs. 3A and 5A, the free end of the elastic piece 24 is inserted between the plate-like pressing portion 31A and the inner wall surface of the coupling 30, thereby holding the free end of the elastic piece 24. The connecting portion 31B is a portion that connects the pressing portion 31A to the inner wall surface of the coupling 30. The connecting portion 31B connects the rear edge of the plate-like pressing portion 31A to the inner wall surface of the coupling 30. As a result, a gap 25 for inserting the free end of the elastic piece 24 is formed between the pressing portion 31A and the inner wall surface of the coupling 30 at the front edge of the pressing portion 31A. Note that the holding portion 31 is not limited to an L-shaped cross section composed of the pressing portion 31A and the connecting portion 31B.

In this reference example, as shown in FIG. 5A, the length by which the holding portion 31 (more specifically, the pressing portion 31A) holds the free end of the elastic piece 24 is defined as L1. Also, as shown in FIG. 5B, the length by which the coupling 30 can move (retract) relative to the plug 20 (housing 22) is defined as L2. In this reference example, the length L1 is shorter than the length L2. This makes it possible to remove the free end of the elastic piece 24 from the holding portion 31 when the coupling 30 is retracted relative to the plug 20.

The release mechanism 32 is a part that elastically deforms the elastic piece 24 to release the engagement between the engagement hole 121 and the engagement protrusion 24A. In this reference example, since the release mechanism 32 is provided in the coupling 30, the elastic piece 24 can be elastically deformed to release the engagement between the engagement hole 121 and the engagement protrusion 24A by moving the coupling 30 relative to the plug 20. Note that the coupling 30 does not have to have the release mechanism 32. The release mechanism 32 is disposed so as to correspond to each of the pair of elastic pieces 24, and is disposed on both the left and right sides of the inner wall surface of the coupling 30. The release mechanism 32 is disposed forward of the retaining portion 31, and here, is provided on the front edge of the coupling 30.

The release mechanism 32 is disposed between the holding portion 31 and the fitting protrusion 24A (see FIG. 5A). As a result, when the coupling 30 is moved rearward relative to the plug 20 (housing 22), the free end of the elastic piece 24 held by the holding portion 31 reaches the position of the release mechanism 32 (see FIG. 5B).

In this reference example, the release mechanism 32 has an inclined surface. The inclined surface is formed so as to protrude inward from the inner wall surface of the coupling 30 toward the front side. In other words, the inclined surface is formed so as to approach the housing main body 23 toward the front side. When the coupling 30 moves rearward relative to the plug 20 (housing 22), the inclined surface of the release mechanism 32 comes into contact with the protruding portion 24B of the elastic piece 24, displacing the free end of the elastic piece 24 radially toward the housing main body 23 (in a direction different from the moving direction of the coupling 30), and the engagement between the fitting hole 121 and the fitting protrusion 24A is released (the fitting protrusion 24A is removed from the fitting hole 121). For one elastic piece 24, two release mechanisms 32 are arranged to sandwich the elastic piece 24 from above and below (see Figures 5A and 5B). This suppresses circumferential positional deviation between the elastic piece 24 and the coupling 30.

As shown in Figures 3A and 3B, the coupling 30 is biased toward the receptacle 10 by the biasing member 35. In other words, the coupling 30 is held in the plug 20 (housing 22) in a state where it is pressed forward by the biasing member 35.

The biasing member 35 is a member that biases the coupling 30 forward relative to the plug 20 (housing 22). In this reference example, the biasing member 35 is, for example, a spring, but other members may be used. The rear end of the biasing member 35 (spring) is in contact with the housing 22, and the front end of the biasing member 35 is in contact with the coupling 30. In other words, the biasing member 35 is disposed between the housing 22 and the coupling 30. The biasing member 35 is disposed in a compressed state between the housing 22 and the coupling 30, and presses the coupling 30 forward relative to the housing 22.

In this reference example, the biasing member 35 biases the coupling 30 forward relative to the plug 20, so that as shown in FIG. 3A, the coupling 30 holds the end (free end) of the elastic piece 24 in a state biased by the biasing member 35. This makes it easier to transition to a state in which the engagement between the mating hole 121 of the receptacle 10 and the mating protrusion 24A of the plug 20 is maintained (a mating maintenance state) when the receptacle 10 and the plug 20 are connected, as described below.

The coupling 30 has a key groove 33 (see FIG. 4B). The key groove 33 is a groove-like portion formed on the inner wall surface of the cylindrical coupling 30, and is formed to fit the key protrusion 233 of the plug 20. The key groove 33 is formed along the front-rear direction, and is formed on the upper side of the inner wall surface of the coupling 30 in this reference example. The coupling 30 is guided by the key protrusion 233 of the plug 20 by the key groove 33 and can move in the front-rear direction relative to the plug 20. In this reference example, the key protrusion 233 of the plug 20 is formed to fit both the key groove 33 of the coupling 30 and the key groove 126 of the receptacle 10. As a result, one key protrusion 233 can have both the function of guiding the movement of the coupling 30 relative to the plug 20 and the function of aligning the plug 20 and the receptacle 10, and the shape of the plug 20 is simplified. However, the plug 20 may also have a separate key protrusion for guiding the coupling 30 (in this case, the plug 20 will have two key protrusions). Also, the coupling 30 does not have to have a key groove 33.

<Connection between receptacle 10 and plug 20>
6A to 6E are explanatory diagrams showing how receptacle 10 and plug 20 are connected.

Figure 6A is an explanatory diagram of the initial state. Because the biasing member 35 biases the coupling 30 forward relative to the plug 20, the holding portion 31 of the coupling 30 holds the end (free end) of the elastic piece 24 while being biased by the biasing member 35. Therefore, in the initial state, both ends of the cantilever-shaped elastic piece 24 are supported. When connecting the receptacle 10 and the plug 20, the worker inserts the plug 20 into the receptacle 10 while holding the housing body 23 of the plug 20 or the coupling 30.

Figure 6B is an explanatory diagram of the state in which the tip portion 231 of the plug 20 is inserted into the receptacle 10. The worker inserts the tip portion 231 of the plug 20 into the receptacle 10 while aligning the key protrusion 233 of the plug 20 with the key groove 126 of the receptacle 10. This allows the receptacle 10 and the plug 20 to be aligned in the circumferential direction (the rotation direction around the axis of the front-rear direction). Also, as shown in Figure 6B, when the tip portion 231 of the plug 20 is inserted into the receptacle 10, the front edge of the elastic piece 24 of the plug 20 enters the guide groove 127 of the receptacle 10. Then, when the plug 20 is further inserted into the receptacle 10 from the state shown in Figure 6B, the elastic piece 24 is guided into the guide groove 127. This further suppresses the circumferential positional deviation between the receptacle 10 and the plug 20. At the stage shown in FIG. 6B, the guide pin 11A of the ferrule 11 of the receptacle 10 has not been inserted into the guide hole of the ferrule 21 of the plug 20.

Figure 6C is an explanatory diagram of the state in which the guide pin 11A begins to be inserted into the guide hole. When the operator further inserts the plug 20 into the receptacle 10 from the state shown in Figure 6B, the guide pin 11A of the ferrule 11 of the receptacle 10 is inserted into the guide hole of the ferrule 21 of the plug 20, as shown in Figure 6C. By inserting the guide pin 11A into the guide hole, the ferrule 11 of the receptacle 10 and the ferrule 21 of the plug 20 are aligned with high precision. Note that at the stage shown in Figure 6C, the mating protrusion 24A of the elastic piece 24 is located forward of the front edge of the receptacle 10 and is not inserted into the receptacle 10.

Figure 6D is an explanatory diagram of the state in which the fitting protrusion 24A of the elastic piece 24 starts to be inserted into the receptacle 10. When the worker further inserts the plug 20 into the receptacle 10 from the state shown in Figure 6C, the guide pin 11A is inserted into the guide hole and the ferrule 11 of the receptacle 10 and the ferrule 21 of the plug 20 approach each other. Also, when the worker further inserts the plug 20 into the receptacle 10 from the state shown in Figure 6C, the fitting protrusion 24A of the elastic piece 24 enters the inside of the housing 12 of the receptacle 10 as shown in Figure 6D. At this time, the fitting protrusion 24A is pushed inward (toward the housing main body 23) and displaced, and the elastic piece 24 is elastically deformed. In this reference example, the elastic piece 24 is elastically deformed with the end (free end) of the elastic piece 24 held by the holding portion 31.

Figure 6E is an explanatory diagram of the state in which the mating projection 24A is mated with the mating hole 121. When the operator further inserts the plug 20 into the receptacle 10 from the state shown in Figure 6D, the mating projection 24A reaches the mating hole 121 of the receptacle 10. When the mating projection 24A reaches the mating hole 121 of the receptacle 10, the elastic deformation of the elastic piece 24 returns to its original state, the mating projection 24A is displaced outward, and the mating projection 24A fits into the mating hole 121 of the receptacle 10. At this time, the end faces of the ferrules butt against each other, and the ferrules 11 and 21 recede relative to the housing 22 (the springs 13 and 27 are compressed and deformed), and are pressed toward the mating ferrule by the springs 13 and 27 with a predetermined pressing force. This completes the connection between the plug 20 and the receptacle 10.

In this reference example, the plug 20 (including the elastic piece 24) is inserted into the receptacle 10, and as shown in FIG. 6E, when the plug 20 and receptacle 10 are connected, the elastic piece 24 is disposed inside the housing 12 of the receptacle 10. Therefore, when the plug 20 and receptacle 10 are connected, the elastic piece 24 is unlikely to receive external force. This makes it possible to prevent the elastic piece 24 from being unexpectedly elastically deformed, and to prevent the engagement between the engagement hole 121 and the engagement protrusion 24A from being unexpectedly released.

In addition, in this reference example, as shown in FIG. 6E, when the plug 20 and the receptacle 10 are connected, the end (free end) of the elastic piece 24 is held by the holding portion 31. By the holding portion 31 holding the free end of the elastic piece 24, it is possible to prevent the free end of the elastic piece 24 from being displaced, and the engagement between the engagement hole 121 and the engagement protrusion 24A can be maintained. Note that the state in which the holding portion 31 holds the free end of the elastic piece 24 to maintain the engagement between the engagement hole 121 and the engagement protrusion 24A is sometimes referred to as the "engagement maintained state."

The coupling 30 of this reference example has a holding portion 31 that holds the end (free end) of the elastic piece 24 in a state where it is biased by the biasing member 35. Therefore, in this reference example, when the fitting protrusion 24A reaches the fitting hole 121 of the receptacle 10, the end (free end) of the elastic piece 24 is held by the holding portion 31. As a result, the fitting protrusion 24A fits into the fitting hole 121 of the receptacle 10 with the end (free end) of the elastic piece 24 held by the holding portion 31. If the fitting protrusion 24A and the fitting hole 121 are fitted together in a state where the end (free end) of the elastic piece 24 is not held by the holding portion 31, there is a risk that the fitting between the fitting hole 121 and the fitting protrusion 24A may suddenly come off after the fitting until the holding portion 31 transitions to a state where it holds the free end of the elastic piece 24 (fitted state). In contrast, in this reference example, when the receptacle 10 and the plug 20 are connected, the receptacle 10 quickly transitions to a state in which the mating hole 121 of the receptacle 10 and the mating protrusion 24A of the plug 20 remain mated (a mating maintenance state), preventing the mating hole 121 and the mating protrusion 24A from accidentally coming loose.

6E, springs 13, 27 of receptacle 10 and plug 20 are compressed and deformed, and the contact portion between the rear edge of mating projection 24A (mechanical reference surface of plug 20) and the front edge of mating hole 121 (mechanical reference surface on the receptacle 10 side) receives the forces of springs 13, 27 of receptacle 10 and plug 20 (the spring force is applied to the contact portion). When receptacle 10 and plug 20 include multiple ferrules (two in this example) as in this reference example, the number of springs 13, 27 increases, and therefore the contact portion between the rear edge of mating projection 24A and the front edge of mating hole 121 receives a large force. Furthermore, when the number of optical fibers in each ferrule 11, 21 is large, it is necessary to increase the force pressing the ferrules 11, 21, and therefore strong springs 13, 27 are used, so that the contact portion between the rear edge of the fitting protrusion 24A and the front edge of the fitting hole 121 receives a large force. Under such circumstances, the frictional force acting between the rear edge of the fitting protrusion 24A and the front edge of the fitting hole 121 becomes large. If the force for restoring the elastic deformation of the elastic piece 24 to its original state is weak under such circumstances, when the fitting protrusion 24A reaches the fitting hole 121 of the receptacle 10, the frictional force may not cause the fitting protrusion 24A to be sufficiently displaced outward, and the fitting protrusion 24A may not be sufficiently fitted into the fitting hole 121.
In contrast, in this reference example, when the receptacle 10 and the plug 20 are connected, the coupling 30 is biased by the biasing member 35, so that the fitting protrusion 24A fits into the fitting hole 121 in a state in which the holding portion 31 holds the end (free end) of the elastic piece 24. That is, in this reference example, when the fitting protrusion 24A reaches the fitting hole 121 of the receptacle 10, the end (free end) of the elastic piece 24 is held by the holding portion 31, and both ends of the elastic piece 24 are supported. For this reason, in this reference example, the force with which the elastic deformation of the elastic piece 24 returns to its original state when the fitting protrusion 24A reaches the fitting hole 121 of the receptacle 10 is stronger than in a state in which the free end of the elastic piece 24 is not held by the holding portion 31 (the elastic piece 24 is in a cantilever supported state). As a result, in this embodiment, the fitting projection 24A can be sufficiently displaced outward against the frictional force, and the fitting projection 24A and the fitting hole 121 can be fitted together reliably.

<Disconnecting the receptacle 10 and the plug 20>
7A to 7E are explanatory diagrams showing how the connection between the receptacle 10 and the plug 20 is released.

Figure 7A is an explanatory diagram of the state when the receptacle 10 and plug 20 are connected. In the state shown in Figure 7A, the mating projection 24A of the plug 20 is mated with the mating hole 121 of the receptacle 10, similar to the state shown in Figure 6E. Also, in the state shown in Figure 7A, the holding portion 31 holds the free end of the elastic piece 24, and the mating between the mating hole 121 and the mating projection 24A is maintained (mating maintained state). When disconnecting the receptacle 10 and plug 20, the operator moves the coupling 30 from the state shown in Figure 7A to the rear side relative to the plug 20 (housing 22).

Figure 7B is an explanatory diagram of the state in which the coupling 30 is moved. When the operator moves the coupling 30 rearward relative to the plug 20 (housing 22), the holding portion 31 (pressing portion 31A) moves rearward relative to the free end of the elastic piece 24, thereby releasing the state in which the free end of the elastic piece 24 is held by the holding portion 31 (the engaged state). Also, when the operator moves the coupling 30 rearward relative to the plug 20 (housing 22), the release mechanism 32 (inclined surface) of the coupling 30 comes into contact with the protruding portion 24B of the elastic piece 24, displacing the free end of the elastic piece 24 radially toward the housing main body 23, thereby releasing the engagement between the engagement hole 121 and the engagement protrusion 24A (the engagement protrusion 24A comes out of the engagement hole 121).

In this reference example, as shown in FIG. 7B, the first portion 241 of the elastic piece 24 is elastically deformed while the second portion 242 is displaced, thereby disengaging the fitting hole 121 from the fitting protrusion 24A. By elastically deforming the first portion 241, the fitting protrusion 24A can be displaced significantly, making it easier to disengage the fitting hole 121 from the fitting protrusion 24A.

Figure 8A is an explanatory diagram of the deformation of the elastic piece 24 of this reference example when the engagement between the engagement hole 121 and the engagement protrusion 24A is released. Figure 8B is an explanatory diagram of the deformation of the elastic piece 24 of the comparative example.

In the elastic piece 24 of the comparative example, the thickness of the second portion 242 is thinner than that of the second portion 242 of the present reference example, and is approximately the same as that of the first portion. Therefore, in the comparative example, the second portion 242 is shaped to be easily elastically deformed compared to the present reference example. In the comparative example, even if the free end (protrusion 24B) of the elastic piece 24 is displaced toward the housing body 23, the fitting protrusion 24A fitted into the fitting hole 121 is difficult to displace against the frictional force, and the fitting between the fitting hole 121 and the fitting protrusion 24A is difficult to release. As already described, when the receptacle 10 or the plug 20 has multiple ferrules or when the number of optical fibers in each ferrule is large, a large frictional force acts between the rear edge of the fitting protrusion 24A and the front edge of the fitting hole 121. Under such circumstances, in the comparative example, the fitting between the fitting hole 121 and the fitting protrusion 24A is difficult to release in particular.

In contrast, in this reference example, the second portion 242 is thicker than the first portion 241. Therefore, the second portion 242 is less likely to elastically deform than the first portion 241. Therefore, as shown in FIG. 8A, when the free end (protrusion 24B) of the elastic piece 24 is displaced toward the housing main body 23, the fitting protrusion 24A that is fitted into the fitting hole 121 is easily displaced against the frictional force, and the fitting between the fitting hole 121 and the fitting protrusion 24A is easily released.

In addition, in this reference example, a gap 25 is formed between the elastic piece 24 (second part 242) and the housing main body 23, and a tapered portion 242A is formed in the second part 242 so that the gap 25 becomes larger toward the free end (protruding portion 24B). If the tapered portion 242A is not formed in the second part 242 (the second part 242 thicker than the first part 241), even if the free end of the elastic piece 24 is displaced so as to contact the housing main body 23, the fitting protrusion 24A cannot be displaced significantly, so that the fitting hole 121 and the fitting protrusion 24A are difficult to disengage. In contrast, in this reference example, by forming the tapered portion 242A in the second part 242, it is possible to displace the free end (protruding portion 24B) of the elastic piece 24 significantly toward the housing main body 23 as shown in FIG. 8A, and it becomes easier to disengage the fitting hole 121 and the fitting protrusion 24A.

Figures 7C and 7D are explanatory diagrams of the state in which the connection between the receptacle 10 and the plug 20 has been released. When the engagement between the engagement hole 121 and the engagement protrusion 24A is released, the compressed and deformed springs 13 and 27 return to their original state, and the force of the springs 13 and 27 at this time separates the receptacle 10 and the plug 20 (see Figure 7C). The operator removes the plug 20 from the receptacle 10 by further retracting the plug 20 from the state shown in Figure 7C to the state shown in Figure 7D.

<Summary of reference examples>
As described above, the optical connector system 1 of the reference example includes a receptacle 10, a plug 20, and a coupling 30 (see FIGS. 1A and 1B). The receptacle 10 has a fitting hole 121, the plug 20 has an elastic piece 24 having a fitting protrusion 24A, and the plug 20 is inserted into the receptacle 10. The coupling 30 is held by the plug 20 and is biased toward the receptacle 10 by a biasing member 35 (see FIGS. 3A and 3B), and can move toward the opposite side to the receptacle 10 with respect to the plug 20 (housing 22). The elastic piece 24 can be elastically deformed in a radial direction (a direction perpendicular to the insertion direction in which the plug 20 is inserted into the receptacle 10) when the plug 20 is inserted into the receptacle 10.

The coupling 30 of the reference example has a holding portion 31 that holds the end (free end) of the elastic piece 24 in a state where it is biased by a biasing member 35 (see Figures 3A and 3B). Therefore, when the fitting protrusion 24A reaches the fitting hole 121 of the receptacle 10, the end (free end) of the elastic piece 24 is held by the holding portion 31. As a result, the fitting protrusion 24A fits into the fitting hole 121 of the receptacle 10 with the end (free end) of the elastic piece 24 held by the holding portion 31. According to the reference example, when the receptacle 10 and the plug 20 are connected, the state where the fitting hole 121 of the receptacle 10 and the fitting protrusion 24A of the plug 20 are kept engaged with each other (fitting maintained state) is quickly transitioned to, so that the fitting hole 121 and the fitting protrusion 24A are prevented from being suddenly disengaged from each other.

====Present Embodiment====
<Outline of this embodiment>
Fig. 9A is an explanatory diagram of a first comparative example. A plug accommodating portion 122 having a cylindrical inner wall surface is formed in the housing 12 of the receptacle 10, and in the first comparative example, the housing 22 of the plug 20 has a cylindrical outer peripheral surface that faces the inner wall surface of the receptacle 10. In addition, in order to fit the housing 22 of the plug 20 into the plug accommodating portion 122 of the receptacle 10, a gap W1 is formed between the inner wall surface of the receptacle 10 and the outer peripheral surface of the plug 20, as shown in the partially enlarged view of Fig. 9A. In the case of the first comparative example, the plug 20 rattles relative to the receptacle 10 by the amount of the gap W1.

Figure 9B is an explanatory diagram of a second comparative example. As already explained, elastic pieces 24 (not shown in Figure 9B; see Figure 4B) are provided on both side surfaces of the housing body 23 of the plug 20. In order to allow the elastic pieces 24 to be elastically deformed, it is necessary to provide a gap 25 between the elastic pieces 24 and the housing body 23. For this reason, as shown in Figure 9B, flat portions 23A are formed on both the left and right side surfaces of the housing body 23 (the sides on which the elastic pieces 24 are provided). As a result, as shown in Figure 9B, the housing body 23 has a shape having two parallel flat portions 23A and two cylindrical portions 23B arranged between the two flat portions 23A.

9B, in the cylindrical portion 23B of the plug 20, a gap W1 is formed between the housing 12 of the receptacle 10 and the housing 22 of the plug 20, as in the first comparative example. When the flat portion 23A is formed on the housing main body 23, the gap W2 between the inner wall surface of the receptacle 10 and the outer peripheral surface of the plug 20 becomes large in the left-right direction in the figure (direction perpendicular to the flat portion 23A). Therefore, when the flat portion 23A is formed on the outer peripheral surface of the plug 20 as in the second comparative example, the wobble of the plug 20 in the direction perpendicular to the flat portion 23A with respect to the receptacle 10 becomes large. In this way, if the wobble between the receptacle 10 and the plug 20 becomes large, the loss of the optical signal (connection loss) may become large.

Figure 9C is an explanatory diagram of this embodiment. In this embodiment, as in the second comparative example, the housing body 23 has two parallel flat surfaces 23A and two cylindrical surfaces 23B disposed between the two flat surfaces 23A.

In this embodiment, a groove 128 is formed on the inner wall surface of the receptacle 10. Also, in this embodiment, the housing body 23 of the plug 20 has a protrusion 234. As shown in the partially enlarged view of FIG. 9C, in this embodiment, the protrusion 234 of the plug 20 fits into the groove 128 of the receptacle 10. In this embodiment, compared to the second comparative example described above, the gap W between the inner wall surface of the receptacle 10 and the outer peripheral surface of the plug 20 in the direction perpendicular to the flat surface portion 23A can be narrowed. This makes it possible to suppress rattling between the receptacle 10 and the plug 20, and to suppress loss of optical signals.

<Configuration of this embodiment>
Fig. 10A and Fig. 10B are perspective views of the optical connector system 2 of this embodiment. Fig. 11 is a perspective view of the receptacle 10 of this embodiment. Fig. 12A is a perspective view of the plug 20 of this embodiment. Fig. 12B is a perspective view of the plug 20 in a state in which the coupling 30 of this embodiment is separated.

The optical connector system 2 of this embodiment has a receptacle 10, a plug 20, and a coupling 30, similar to the optical connector system 1 of the reference example. The receptacle 10 has a fitting hole 121. The plug 20 has an elastic piece 24 with a fitting protrusion 24A, and is inserted into the receptacle 10. The coupling 30 is held by the plug 20, and is biased toward the receptacle 10 by a biasing member 35 (not shown: see Figures 3A and 3B) similar to the reference example, and can move toward the opposite side to the receptacle 10 with respect to the plug 20 (housing 22). The elastic piece 24 can be elastically deformed in the radial direction (direction perpendicular to the insertion direction in which the plug 20 is inserted into the receptacle 10) when the plug 20 is inserted into the receptacle 10.
Also in this embodiment, as in the reference example, coupling 30 has a holding portion 31 that holds an end (free end) of elastic piece 24 in a state where it is biased by biasing member 35 (not shown: see FIGS. 3A and 3B ). Therefore, also in this embodiment, when fitting protrusion 24A reaches fitting hole 121 of receptacle 10, the end (free end) of elastic piece 24 is held by holding portion 31. As a result, also in this embodiment, fitting protrusion 24A fits into fitting hole 121 of receptacle 10 with the end (free end) of elastic piece 24 held by holding portion 31. Therefore, in this embodiment as well, as in the reference example, when the receptacle 10 and the plug 20 are connected, the engagement between the mating hole 121 of the receptacle 10 and the mating protrusion 24A of the plug 20 is maintained quickly (an engagement maintained state), thereby preventing the engagement between the mating hole 121 and the mating protrusion 24A from suddenly coming loose.

Receptacle 10
11A and 11B, the receptacle 10 (more specifically, the housing 12) of this embodiment has a plug accommodating portion 122, similar to the reference example. The inner wall surface of the plug accommodating portion 122 is formed into a cylindrical shape. The receptacle 10 of this embodiment has grooves 128 in the cylindrical inner wall surface. In this embodiment, the receptacle 10 has four grooves 128.

The groove 128 is a groove-like portion formed on the inner wall surface of the cylindrical housing 12, and is formed to fit the protrusion 234 of the plug 20 (see Figures 9C, 12A, and 12B). The groove 128 is formed along the front-rear direction. As shown in Figure 11B, in this embodiment, the groove 128 is located forward (toward the plug 20) of the recess 123 of the plug accommodating portion 122. This is because if the groove 128 were also formed in the recess 123, a gap would be formed between the inner wall surface of the recess 123 and the O-ring 231A (waterproof member) of the plug 20, and water would enter through the gap.

The grooves 128 are formed in a V-groove shape having a first surface 128A and a second surface 128B. The first surface 128A is a surface parallel to the front-rear and left-right directions. The second surface 128B is a surface parallel to the front-rear and left-right directions. The first surface 128A of a certain groove 128 and the first surface 128A of the alignment groove 128 adjacent to it in the left-right direction are located on the same plane. In addition, the second surface 128B of a certain groove 128 and the second surface 128B of the alignment groove 128 adjacent to it in the up-down direction are located on the same plane. Therefore, when the first surface 128A and the second surface 128B of each of the four grooves 128 are extended, a virtual square tube is formed. When the receptacle 10 is viewed from the front side, the ferrule 11 of the receptacle 10 is arranged inside this virtual square tube.

Plug 20
12A and 12B , the plug 20 has a tip portion 231 and a main body portion 232. The tip portion 231 is a cylindrical portion on the front side (the receptacle 10 side) of the plug 20 (housing 22). The outer circumferential surface of the tip portion 231 is formed into a cylindrical shape so that an O-ring 231A can be disposed on the outer circumferential surface of the tip portion 231. The outer circumferential surface of the tip portion 231 faces the inner wall surface of the plug accommodating portion 122 of the receptacle 10.

The main body 232 is a part that constitutes the housing main body 23 together with the tip portion 231. The main body 232 is a part rearward of the tip portion 231 (opposite the receptacle 10 side). Elastic pieces 24 are arranged on both the left and right side surfaces of the main body 232. The main body 232 has a flat portion 23A, a cylindrical portion 23B, and a protrusion 234.

The flat surface 23A is a planar portion that constitutes the outer peripheral surface of the main body 232. The flat surface 23A is disposed on the side where the elastic piece 24 is provided, and here, is disposed on both the left and right side surfaces of the main body 232. This forms a gap 25 between the flat surface 23A and the elastic piece 24, allowing the elastic piece 24 to be displaced toward the main body 232. In this embodiment, two flat surfaces 23A are disposed on both the left and right side surfaces of the main body 232.

The cylindrical portion 23B is a portion having a cylindrical outer peripheral surface that faces the inner wall surface of the receptacle 10. The cylindrical portion 23B is disposed between the two flat portions 23A. In this embodiment, the two cylindrical portions 23B are disposed above and below the main body portion 232. A key protrusion 233 is disposed on the upper cylindrical portion 23B.

The protrusion 234 is a ridge protruding from the outer circumferential surface of the main body 232 (the outer circumferential surface of the cylindrical portion 23B) and is a portion that fits into the groove 128 of the receptacle 10. The protrusion 234 is formed to fit into the groove 128 of the receptacle 10. The protrusion 234 is formed along the front-rear direction. In this embodiment, the protrusion 234 fits into the groove 128 of the receptacle 10, thereby narrowing the gap W between the inner wall surface of the receptacle 10 and the outer circumferential surface of the plug 20 in the direction perpendicular to the flat surface portion 23A (see FIG. 9C). Therefore, according to this embodiment, the protrusion 234 fits into the groove 128 of the receptacle 10, thereby allowing the receptacle 10 and the plug 20 to be aligned with high precision (aligned in a direction perpendicular to the front-rear direction). In this embodiment, the main body 232 has four protrusions 234.

The protrusion 234 is formed in a triangular shape (inverted V-shape) having a first surface 234A and a second surface 234B. The first surface 234A is a surface parallel to the front-rear direction and the left-right direction. The second surface 234B is a surface parallel to the front-rear direction and the up-down direction. The first surface 234A of a certain protrusion 234 and the first surface 234A of the protrusion 234 adjacent in the left-right direction are located on the same plane. In addition, the second surface 234B of a certain protrusion 234 and the second surface 234B of the protrusion 234 adjacent in the up-down direction are located on the same plane. Therefore, when the first surface 234A and the second surface 234B of each of the four protrusions 234 are extended, a virtual square tube is formed. When the plug 20 is viewed from the front side, the ferrule 21 of the plug 20 is arranged inside this virtual square tube. The imaginary square tube formed by the four protrusions 234 fits into the imaginary square tube formed by the four grooves 128 of the receptacle 10.

In this embodiment, the protrusion 234 protrudes in a direction (here, the up-down direction) perpendicular to the direction in which the pair of flat portions 23A face each other (here, the left-right direction). In other words, as shown in FIG. 9C, the second surface 234B of the protrusion 234 protrudes in the up-down direction beyond the extension of the outer circumferential surface of the cylindrical portion 23B. This makes it possible to narrow the gap W between the inner wall surface of the receptacle 10 and the outer circumferential surface of the plug 20 in the direction perpendicular to the flat portions 23A (here, the left-right direction) (see FIG. 9C).

In addition, in this embodiment, the protrusion 234 extends from the planar portion 23A. In other words, as shown in FIG. 9C, the second surface 234B of the protrusion 234 is configured as an extension of the planar portion 23A. This allows the protrusion 234 to be realized with a simple configuration. However, the second surface 234B of the protrusion 234 does not have to be disposed on the same plane as the planar portion 23A.

In addition, in this embodiment, the protrusion 234 has a second surface 234B parallel to the flat surface 23A, and a first surface 234A perpendicular to the flat surface 23A. This makes it possible to suppress wobbling between the receptacle 10 and the plug 20 in two directions, the left-right direction and the up-down direction. Note that since the two directions, the left-right direction and the up-down direction, correspond to directions perpendicular to the optical axis (the optical axis of the optical fiber held by the ferrules 11 and 21), suppressing wobbling in these two directions is particularly effective in suppressing loss of optical signals.

In this embodiment, the protrusion 234 is disposed between the planar portion 23A and the cylindrical portion 23B. As in the second comparative example shown in FIG. 9B, the gap W2 between the planar portion 23A and the cylindrical portion 23B in the direction perpendicular to the planar portion 23A becomes large. In contrast, in this embodiment, by disposing the protrusion 234 between the planar portion 23A and the cylindrical portion 23B, the gap W in the direction perpendicular to the planar portion 23A can be reduced as shown in FIG. 9C.

In addition, in this embodiment, the number of protrusions 234 is an even number (four in this example). By making the number of protrusions 234 an even number, the protrusions 234 can be arranged symmetrically while the surface of one protrusion 234 (particularly the second surface) can be arranged parallel to the surface of another protrusion 234. Note that the number of protrusions 234 is not limited to four.

Figures 13A and 13B are explanatory diagrams of modified arrangements of the protrusions 234. As shown in these modified examples, the main body 232 may have two protrusions 234, and the second surface of one protrusion 234 may be arranged parallel to the second surface of the other protrusion 234. Even with this arrangement, it is possible to suppress the gap W in the direction perpendicular to the flat surface portion 23A.

The protrusions 234 are provided on each of the two planar portions 23A. In other words, at least one protrusion 234 is provided on one of the two planar portions 23A, and at least one protrusion is also provided on the other planar portion 23A. This makes it possible to narrow the gap W between the inner wall surface of the receptacle 10 and the outer peripheral surface of the plug 20 in the direction perpendicular to the planar portion 23A (here, the left-right direction) on both planar portions 23A (see FIG. 9C).

Also, as shown in Figures 12A and 12B, the end face 234C on the front side (the receptacle 10 side) of the protrusion 234 is inclined. In other words, the direction perpendicular to the end face on the front side (the receptacle 10 side) of the protrusion 234 is inclined with respect to the front-to-rear direction. This is because if the front end face of the protrusion 234 were perpendicular to the front-to-rear direction, when inserting the plug 20 into the receptacle 10, the end face of the protrusion 234 would hit the edge of the opening of the receptacle 10 (the front edge of the groove 128 of the housing 12), making it difficult to insert the plug 20. In contrast, in this embodiment, the end face of the protrusion 234 is inclined, making it easier to insert the plug into the receptacle 10.

In this embodiment, when the plug 20 is inserted into the receptacle 10, the end face of the protrusion 234 begins to be inserted into the front edge of the groove 128 of the receptacle 12 before the guide pin 11A (see FIG. 11B) of the ferrule 11 of the receptacle 10 is inserted into the guide hole of the ferrule 21 of the plug 20. That is, in this embodiment, when the guide pin 11A begins to be inserted into the guide hole as shown in FIG. 6C, the protrusion 234 is already engaged with the groove 128 of the receptacle 12. As a result, the plug 20 is aligned with the receptacle 10 by the engagement of the protrusion 234 with the groove 128 (alignment in the direction perpendicular to the front-rear direction), and then the guide pin 11A is inserted into the guide hole of the ferrule 21, so that the end face of the ferrule 21 can be prevented from being damaged by the guide pin 11A.

14A and 14B are explanatory diagrams of a modified example of the plug 20. In this modified example, the end face of the protrusion 234 is located behind the fitting protrusion 24A of the elastic piece 24, and when the plug 20 is inserted into the receptacle 10, the end face of the protrusion 234 begins to be inserted into the front edge of the groove 128 of the receptacle 12 after the guide pin 11A (see FIG. 11B) of the ferrule 11 is inserted into the guide hole of the ferrule 21 of the plug 20. Even with the configuration of this modified example, when the receptacle 10 and the plug 20 are connected, the protrusion 234 is engaged with the groove 128 of the receptacle 12. Therefore, even in this modified example, when the receptacle 10 and the plug 20 are connected, rattling between the receptacle 10 and the plug 20 can be suppressed, and loss of optical signals can be suppressed.

Coupling 30
As shown in FIG. 12B, the coupling 30 of this embodiment has four grooves 34. The grooves 34 are groove-shaped portions formed on the inner wall surface of the cylindrical coupling 30, and are formed to fit the protrusions 234 of the plug 20. The grooves 34 are formed along the front-rear direction. The grooves 34 are formed in a V-groove shape having a first surface 34A and a second surface 34B, similar to the grooves 128 of the receptacle 10 (see FIG. 9C and FIG. 11B). In this embodiment, the protrusions 234 of the plug 20 are formed to fit both the grooves 34 of the coupling 30 and the grooves 128 of the receptacle 10. As a result, one protrusion 234 can have both a function of aligning the coupling 30 with respect to the plug 20 and a function of aligning the plug 20 with the receptacle 10, and the shape of the plug 20 is simplified.

The shapes of the receptacle 10 and the plug 20 are not limited to those in this embodiment. For example, the shapes of the receptacle 10 and the plug 20 may be shapes that are compatible with FAS connectors, FA connectors, etc., or may be other shapes. Also, as long as the plug 20 has a flat surface portion 23A, it does not necessarily have to have an elastic piece 24.

===Other embodiments===
The above-mentioned embodiment is for the purpose of facilitating understanding of the present invention, and is not intended to limit the present invention. The present invention can be modified or improved without departing from the spirit of the present invention, and it goes without saying that the present invention includes equivalents thereof.

1 Optical connector system, 10 Receptacle,
11 ferrule, 11A guide pin,
12 housing, 121 fitting hole,
122 plug receiving portion, 123 recessed portion,
126 key groove, 127 guide groove,
128 groove, 128A first surface, 128B second surface,
13 spring, 14 spring support,
20 Plug, 21 Ferrule,
22 Housing, 23 Housing body,
23A: Planar portion; 23B: Cylindrical portion;
231 tip portion, 231A O-ring,
232 Main body portion, 233 Key protrusion,
234 protrusion, 234A first surface, 234B second surface, 234C end surface,
24 elastic piece, 24A fitting projection, 24B protruding portion,
241 first portion, 242 second portion, 242A tapered portion,
25 gap, 27 spring, 28 spring support,
30 Coupling, 31 Holding portion,
31A holding portion, 31B connecting portion,
32 release mechanism, 33 key groove,
34 groove, 34A first surface, 34B second surface,
35 biasing member

Claims (9)

a receptacle including a plug receiving portion having a cylindrical inner wall surface and a groove on the inner wall surface;
a plug that is inserted into the plug accommodating portion and has a tip portion that is inserted into the receptacle and a main body portion;
Equipped with
The tip portion has an outer circumferential surface shaped like a cylindrical surface facing the inner wall surface,
the main body portion has two parallel flat surfaces, two cylindrical portions disposed between the two flat surfaces and facing the inner wall surface, and a protrusion portion that fits into the groove ,
The protrusion is disposed between the flat portion and the cylindrical portion.
Optical connector system. 2. The optical connector system of claim 1,
The optical connector system according to claim 1, wherein the protrusion protrudes in a direction perpendicular to the direction in which the pair of planar portions face each other. 3. The optical connector system according to claim 1,
The optical connector system according to claim 1, wherein the protrusion extends from the planar portion. 4. The optical connector system according to claim 3,
The optical connector system according to claim 1, wherein the protrusion has a surface parallel to the flat surface and a surface perpendicular to the flat surface. The optical connector system according to any one of claims 1 to 4 ,
4. An optical connector system according to claim 1, wherein the number of said projections is an even number. The optical connector system according to any one of claims 1 to 5 ,
An optical connector system, characterized in that the protrusion is provided on each of the two planar portions. The optical connector system according to any one of claims 1 to 6 ,
An optical connector system comprising: an optical connector having a waterproof member disposed on an outer peripheral surface of the tip portion . 8. The optical connector system of claim 7 ,
the plug accommodating portion of the receptacle has a recess that accommodates the tip end of the plug,
An optical connector system according to claim 1, wherein the groove is located closer to the plug than the recess. The optical connector system according to any one of claims 1 to 8 ,
An optical connector system, wherein an end face of said projection on said receptacle side is inclined.

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