Optical connector

An optical connector in which a seal member is difficult to be damaged during assembly. A seal member-accommodating portion that accommodates the seal member in a compressed state is formed as an intermediate portion of a through hole of a housing. When an insertion member is inserted into the through hole, an insertion portion of the insertion member presses the seal member into the seal member-accommodating portion.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to an optical connector, and more particularly to an optical connector having waterproof properties.

2. Description of Related Art

Conventionally, there has been proposed an optical connector comprising a shell member, an insulator, ferrules, sealing members, and fiber holding members (see Japanese Laid-Open Patent Publication (Kokai) No. H10-311933, Paragraph Nos. 0016 to 0022 and FIG. 1).

The shell member has a substantially hollow cylindrical shape and has a flange-shaped shell-holding portion formed on an outer peripheral surface thereof. A protrusion is formed on an inner peripheral surface of a front end portion of the shell member, and a groove is formed in an inner peripheral surface of a rear end portion of the shell member along a circumferential direction thereof. A stopper member is removably mounted on the groove.

The insulator has a substantially hollow cylindrical shape, and is inserted into the shell member to be fixed by the protrusion of the shell member and the stopper member. The insulator is formed with a through hole. The through hole extends in a fitting/removing direction of the optical connector with respect to a mating optical connector. A female screw is formed on an inner peripheral surface of a rear end portion of the through hole. An inner diameter of a front end portion of the through hole is smaller than inner diameters of the other portions of the through hole, and the inner diameters of the other portions of the through hole are substantially equal to each other.

The ferrule has a substantially hollow cylindrical shape and holds an optical fiber strand of one end portion of an optical fiber code. The ferrule includes a flange-shaped ferrule-holding portion.

The ferrule is inserted into the through hole of the insulator. A front end portion of the ferrule protrudes from the front portion of the through hole. The ferrule-holding portion of the ferrule is brought into abutment with a stepped surface (stepped surface that is adjacent to a rear of the front end portion of the through hole) in the through hole of the insulator.

The sealing member is formed of an elastic material such that it has a substantially annular shape, and is mounted on a rear end portion of the ferrule. The sealing member prevents water from passing through the through hole.

The fiber-holding member has a substantially hollow cylindrical shape and includes a fiber through hole. The optical fiber code is passed through the fiber through hole. Also, the rear end portion of the ferrule is inserted into a front end portion of the fiber through hole. A male screw that is screwed into the female screw of the insulator is formed on an outer peripheral surface of a rear end portion of the fiber-holding member.

Next, a description will be given of assembly of the conventional optical connector.

As a preparation for the assembly, the optical fiber code is passed through the fiber-holding member and the ferrule having the sealing member mounted thereon is caused to hold the optical fiber strand of the one end portion of the optical fiber code, in advance.

First, the insulator is inserted into the shell member until the insulator is brought into abutment with the protrusion of the shell member.

When the insulator is brought into abutment with the protrusion of the shell member, the stopper member is mounted in the groove of the shell member to fix the insulator to the shell member.

Next, the ferrule having the sealing member mounted thereon is inserted into the through hole of the insulator and is pushed in to the front end portion of the through hole by using e.g. a jig. When the ferrule is pushed in, the front end portion of the ferrule protrudes forward from the through hole.

Finally, the fiber-holding member is inserted into the through hole of the insulator, and the male screw of the fiber-holding member is screwed into the female screw of the insulator, whereby the sealing member is pressed to the ferrule-holding portion of the ferrule with a front end of the fiber-holding member.

When through the above-described process, the assembly of the optical connector is completed.

In the above-described optical connector, when the ferrule having the sealing member mounted thereon is inserted into the through hole of the insulator and is pressed in to the front end portion of the through hole by using e.g. a jig, the sealing member is moved while being rubbed against the inner peripheral surface (especially the female screw portion) of the through hole. Therefore, there is a fear that the sealing member is damaged. As a result, there is a fear that the optical connector cannot be made waterproof.

SUMMARY OF THE INVENTION

The present invention has been made in view of these circumstances, and an object thereof is to provide an optical connector having a seal member which is difficult to be damaged during assembly.

To attain the above object, the present invention provides an optical connector comprising a housing including a through hole, an insertion member that is inserted into the through hole, a holding member that holds an optical fiber and is accommodated in the through hole, and a seal member that is mounted on an outer peripheral surface of the holding member and prevents fluid from passing through the through hole, the through hole of the housing including a seal member-accommodating portion formed as an intermediate portion thereof for accommodating the seal member in a compressed state, the insertion member being provided with a pressing portion that presses the seal member into the seal member-accommodating portion when the insertion member is inserted into the through hole.

With the arrangement of the optical connector according to the present invention, when the seal member is pressed into the seal member-accommodating portion as an intermediate portion of the through hole by the pressing portion of the insertion member inserted into the through hole of the housing, the seal member is compressed, and by a restoring force thereof, the seal member is pressed onto an inner peripheral surface of the seal member-accommodating portion and onto an outer peripheral surface of the holding portion, whereby a high sealing force is generated. Also, it is not until the seal member is pressed into the seal member-accommodating portion as the intermediate portion of the through hole of the housing that the seal member is brought into contact with an inner peripheral surface of the through hole. In other words, the seal member is not brought into contact with the inner peripheral surface of the through hole until the seal member is pressed into the seal member-accommodating portion.

Preferably, the holding member comprises a ferrule for holding the optical fiber, and a flange member that is mounted on an insertion member-side end portion of the ferrule and includes a flange portion for receiving the seal member when the insertion member is inserted into the through hole, and at least one recess is formed in an outer peripheral surface of the flange portion, and a protruding portion that is capable of fitting to the recess is formed on an inner peripheral surface of the through hole of the housing.

Preferably, the insertion member includes an operating portion that protrudes outside from the through hole when the insertion member is inserted into the through hole.

According to this invention, the seal member is difficult to be damaged during assembly of the optical connector.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention will now be described in detail with reference to the drawings showing preferred embodiments thereof.

As shown inFIG. 1, an optical connector1is used in combination with an optical adapter20.

As shown inFIGS. 2 and 3, the optical connector1is comprised of a housing3, an insertion member5, a holding member7, a seal member9, a sleeve11, and a seal member12. The optical connector1is connected to an optical fiber code19and is fixed to a panel17. The optical fiber code19is comprised of an optical fiber strand191composed of an optical fiber formed of a fiber-shaped core and a clad covering the core, none of which are shown, and a primary coating covering the optical fiber, a secondary coating192covering the optical fiber strand191, and an outer sheath193covering the secondary coating192.

As shown inFIGS. 4,5, and6, the housing3includes a plate-shaped portion31, a hollow rectangular prism-shaped portion32, and a hollow cylindrical portion33.

The plate-shaped portion31has a rectangular shape, and has a screw insertion hole311formed in each corner thereof. A groove312is formed in a surface of the plate-shaped portion31toward the hollow cylindrical portion33. When viewed from a rear side of the housing3, the groove312encircles the hollow cylindrical portion33(seeFIG. 5).

The hollow rectangular prism-shaped portion32is located on a front side of the plate-shaped portion31. Two corner portions of the hollow rectangular prism-shaped portion32are each formed with a guide hole321. The two guide holes321are located on the same diagonal line. A pin insertion hole322is formed in each side of the hollow rectangular prism-shaped portion32(seeFIG. 4). A Pin35is inserted into each pin insertion hole322and is fixed to the hollow rectangular prism-shaped portion32(seeFIG. 3). A key groove323is formed in an upper surface of the hollow rectangular prism-shaped portion32as viewed inFIG. 4.

The hollow cylindrical portion33is located on a rear side of the plate-shaped portion31.

A through hole34is formed in a central portion of the housing3. As shown inFIG. 6, the inner diameter of the through hole34is not uniform. The through hole34is comprised of a ferrule-holding portion341, a flange-accommodating portion342, a seal member-accommodating portion343, an accommodating portion344, a female screw portion345, and a receiving portion346. These portions341,342,343,344,345, and346are disposed such that the receiving portion346, the ferrule-holding portion341, the flange-accommodating portion342, the seal member-accommodating portion343, the accommodating portion344, and the female screw portion345are disposed in the mentioned order in a direction from a front side (left side as viewed inFIG. 6) to the rear side (right side as viewedFIG. 6) of the housing3.

In a fitting/removing direction D of the housing3with respect to the optical adapter20, the ferrule-holding portion341is located in a substantially intermediate position of the through hole34. The inner diameter of the ferrule-holding portion341is smaller than that of any other portion (e.g. the flange-accommodating portion342). The flange-accommodating portion342is continuous with a rear side of the ferrule-holding portion341. The inner diameter of the flange-accommodating portion342is larger than the inner diameter of the ferrule-holding portion341. A protruding portion342ais formed on an inner peripheral surface of the flange-accommodating portion342(seeFIG. 5). The seal member-accommodating portion343is continuous with a rear side of the flange-accommodating portion342. The inner diameter of the seal member-accommodating portion343is larger than the inner diameter of the flange-accommodating portion342. The accommodating portion344is continuous with a rear side of the seal member-accommodating portion343. The inner diameter of the accommodating portion344is larger than the inner diameter of the seal member-accommodating portion343. The female screw portion345is continuous with a rear side of the accommodating portion344. The inner diameter of the female screw portion345is smaller than the inner diameter of the accommodating portion344. The receiving portion346is continuous with a front side of the ferrule-holding portion341. The receiving portion346includes a large-diameter portion346aand a small-diameter portion346b. The large-diameter portion346ais located on a front side of the small-diameter portion346b. The inner diameter of the large-diameter portion346ais larger than the inner diameter of the small-diameter portion346b.

As shown inFIG. 2, the insertion member5includes a pressing portion51, a male screw portion52, and an operating portion53, and is inserted into the through hole34of the housing3except for the operating portion53. The pressing portion51has a hollow cylindrical shape, and is inserted into the seal member-accommodating portion343when the male screw portion52is screwed into the female screw portion345of the through hole34. The male screw portion52has a cylindrical shape and is continuous with a rear side of the pressing portion51. The outer diameter of the male screw portion52is larger than the outer diameter of the pressing portion51. The male screw portion52is screwed into the female screw portion345. A through hole54is formed in a central portion of the insertion member5.

As shown inFIG. 2, the holding member7holds the optical fiber strand191and is accommodated in the through hole34of the housing3. As shown inFIG. 7, the holding member7is comprised of a ferrule71and a flange member72. InFIG. 7, the upper half of the holding member7is cut off.

The ferrule71is made of e.g. zirconia and has a substantially hollow cylindrical shape, as shown inFIG. 7. A holding hole711is formed in a central portion of the ferrule71. The optical fiber strand191of the optical fiber code19is inserted into the holding hole711, and is held by the ferrule71. A tapered surface712is formed on a rear end portion of the ferrule71. The tapered surface712is continuous with an inner peripheral surface of the holding hole711. The tapered surface712guides the optical fiber strand191into the holding hole711.

The flange member72is made of e.g. stainless steel and includes a flange portion721, a large-diameter portion722, and a small-diameter portion723. Four recesses721aare formed at equally-spaced intervals in an outer peripheral surface of the flange portion721. The flange portion721is accommodated in the flange-accommodating portion342of the through hole34of the housing3. At this time, the protruding portion342aof the housing3is fitted to one of the four recesses721a. By doing so, the holding member7is prevented from rotating. Also, by properly selecting one recess721afrom the four recesses721awhich is to be fitted to the protruding portion342a, it is possible to adjust a position of the optical fiber strand191around an optical axis with respect to a mating optical fiber strand (not shown). The large-diameter portion722is continuous with a rear side of the flange portion721. The outer diameter of the large-diameter portion722is smaller than the outer diameter of the flange portion721. The small-diameter portion723is continuous with a rear side of the large-diameter portion722. The outer diameter of the small-diameter portion723is smaller than the outer diameter of the large-diameter portion722.

A large-diameter hole724and a small-diameter hole725are formed in a central portion of the flange member72. The large-diameter hole724extends from a front end surface of the flange portion721to an intermediate location of the large-diameter portion722in a longitudinal direction L of the holding member7. The large-diameter hole724receives a rear end portion of the ferrule71. The rear end portion of the ferrule71is held by the large-diameter portion722. The small-diameter hole725extends from the intermediate location of the large-diameter portion722to a rear end of the small-diameter portion723in the longitudinal direction L. The small-diameter hole725permits the optical fiber strand191of the optical fiber code19to pass through the holding hole711of the ferrule71and receives a front end portion of the secondary coating192. The outer diameter of the small-diameter hole725is substantially the same as the outer diameter of the outer sheath193of the optical fiber code19.

As shown inFIGS. 2 and 7, the seal member9is mounted on an outer peripheral surface of the large-diameter portion722of the flange member72and is brought into contact with the flange portion721. The seal member9is formed of an elastic material such that it has a substantially ring shape, and is implemented e.g. by an O ring. The seal member9is accommodated in the seal member-accommodating portion343of the through hole34of the housing3in a state in which the seal member9is mounted on the large-diameter portion722. At this time, the seal member9is sandwiched between the outer peripheral surface of the large-diameter portion722and an inner peripheral surface of the seal member-accommodating portion343to become compressed in a radial direction (the direction of the outer diameter) of the seal member9.

As shown inFIG. 2, the sleeve11receives the small-diameter portion723of the flange member72and a front end portion of the outer sheath193of the optical fiber code19and couples the holding member7and the optical fiber code19to each other.

As shown inFIG. 2, the seal member12is accommodated in the groove312of the plate-shaped portion31of the housing3and seals between the plate-shaped portion31and the panel17when the plate-shaped portion31is fixed to the panel17with screws18.

As shown inFIGS. 9 and 10, the optical adapter20includes a housing21, a split sleeve22, a sleeve holder23, a plate24, and levers25.

The housing21includes a housing body211and a fitting portion212. The fitting portion212is continuous with a rear surface of the housing body211. A key groove212ais formed in a top of the fitting portion212. A mating optical connector40(seeFIGS. 17 and 18) is fitted to the fitting portion212.

The split sleeve22is accommodated in and held by the sleeve holder23.

The sleeve holder23is comprised of a first holder member231and a second holder member232.

The plate24is sandwiched between the first holder member231and the second holder member232. The plate24is provided with a pair of guide pins241. The guide pins241are inserted into the guide holes321(seeFIG. 16) of the housing3of the optical connector1. The plate24is fixed to a front surface of the housing body211with screws26.

Each lever25is rotatably attached to the housing21. The lever25has a hook portion251formed in a front end portion thereof. The hook portion251is hooked to an associated one of the pins35(seeFIG. 16) of the optical connector1. By doing so, the optical adapter20is locked to the optical connector1.

Next, a description will be given of assembly of the optical connector1with reference toFIGS. 11 to 15. Although the optical adapter20is fitted to the housing3of the optical connector1inFIGS. 11 to 15, it is not necessary that the optical adapter20is fitted to the housing3, when the holding member7, the sleeve11, the seal member9, and the insertion member5are assembled to the housing3.

As shown inFIG. 11, first, after combining the flange member72having the seal member9mounted thereon with the ferrule71, the optical fiber strand191of the optical fiber code19is inserted into the ferrule71via the flange member72, and then the optical fiber strand191is bonded to the ferrule71. In doing this, the optical fiber code19is passed through the insertion member5and the sleeve11in advance. Also, a front end of the outer sheath193of the optical fiber code19is brought into abutment with the rear end of the small-diameter portion723of the flange member72.

Next, the sleeve11is moved until the sleeve11is brought into abutment with the large-diameter portion722of the flange member72.

Then, by pinching the sleeve11, as shown inFIG. 12, the sleeve11is inserted into the through hole34until the seal member9mounted on the flange member72is brought into abutment with a rear end of the seal member-accommodating portion343of the through hole34of the housing3. At this time, since the ferrule71is inserted into the split sleeve22of the optical adapter20, deflection of the ferrule71is suppressed.

Next, as shown inFIG. 13, the insertion member5is inserted into the through hole34until the male screw portion52of the insertion member5is brought into abutment with the female screw portion345of the through hole34(at this time, no action is taken to screw the insertion member5into the through hole34). As a result, the seal member9is pressed into the seal member-accommodating portion343of the through hole34by the pressing portion51of the insertion member5. The seal member9pressed into the seal member-accommodating portion343becomes compressed in the radial direction thereof, sealing the through hole34.

Then, as shown inFIG. 14, the insertion member5is pulled out of the through hole34once. As a result, the seal member9accommodated in the seal member-accommodating portion343can be seen from outside, thereby making it possible to confirm whether the seal member9is neither twisted nor broken.

Finally, as shown inFIG. 15, the insertion member5is inserted into the through hole34once again to screw the male screw portion52of the insertion member5into the female screw portion345of the housing3. As a result, the seal member9is pressed by the pressing portion51of the insertion member5and moved frontward in the seal member-accommodating portion343.

When through the above-described process, the assembly of the optical connector1is completed.

Next, a description will be given of an operation for connecting between the optical connector1and the mating optical connector40via the optical adapter20with reference toFIGS. 16 to 18.

As shown inFIG. 16, first, the optical adapter20is caused to face the optical connector1fixed to the panel17, and the pair of guide pins241of the optical adapter20(inFIG. 16, only one guide pin241is shown) are inserted into the associated guide holes321of the optical connector1, respectively. As a result, the split sleeve22of the optical adapter20(seeFIG. 2) is guided in the fitting/removing direction D, and the ferrule71of the optical connector1is relatively inserted into the split sleeve22. The ferrule71in the split sleeve22is positively held by the split sleeve22.

Next, the lever25of the optical adapter20is rotated such that the hook portions251of the lever25are hooked to the pins35of the optical connector1to thereby fix the optical adapter20to the optical connector1(seeFIG. 17).

Finally, as shown inFIG. 17, the mating optical connector40is caused to face the optical adapter20, and is inserted into the fitting portion212of the optical adapter20in the fitting/removing direction D. At this time, as shown inFIG. 18, a key41of the mating optical connector40is inserted into the key groove212aof the fitting portion212of the optical adapter20. By doing so, abnormal fitting of the mating optical connector40and the optical adapter20is prevented.

By the above-described operation, the optical connector1and the mating optical connector40are connected to each other via the optical adapter20.

According to the present embodiment, the seal member9is not compressed until the seal member9is pressed into the seal member-accommodating portion343as an intermediate portion of the through hole34, i.e., it is not until the seal member9is pressed into the seal member-accommodating portion343that the seal member9is compressed. Therefore, damage to the seal member9is suppressed compared to the above-described related art where a seal member is compressed as soon as the seal member is inserted into the through hole of a housing, and is moved to a predetermined position (seal member-fixing position) while being rubbed against an inner peripheral surface of the through hole.

Also, after the seal member9is pressed into the seal member-accommodating portion343, when the insertion member5is pulled out of the through hole34, it is possible to confirm from outside with the eye whether the seal member9accommodated in the seal member-accommodating portion343is properly accommodated in the seal member-accommodating portion343and whether the seal member9is not damaged. At this time, since the insertion member5is not screwed into the through hole34yet, the insertion member5can be easily removed from the housing3, whereby it is possible to quickly perform the confirmation operation on the seal member9.

Further, since the optical connector1has the sleeve11, the optical fiber strand191of the optical fiber code19can be inserted into the through hole34of the housing3by pinching the sleeve11, whereby the optical fiber strand191is less likely to be damaged.

Also, since the insertion member5includes the operating portion53, the insertion member5can be easily operated by operating the operating portion53.

It should be noted that although in the above-described embodiment, the holding member7is formed of the ferrule71and the flange member72, the holding member may be formed only of the ferrule.

Also, although the above-described insertion member5includes the operating portion53that protrudes from the through hole34, the operating portion53that protrudes from the through hole34is not necessarily required.

It should be noted that although in the above-described embodiment, the ferrule71holds the optical fiber strand191(the ferrule71indirectly holds the optical fiber via the primary coating), the ferrule71may either directly hold the optical fiber or indirectly hold the optical fiber via the primary coating and the secondary coating192.

It is further understood by those skilled in the art that the foregoing are the preferred embodiments of the present invention, and that various changes and modification may be made thereto without departing from the spirit and scope thereof.