End configuration of optical connector

Abstract

An end structure of an optical connector includes a ferrule, a spring, a spring pusher, a housing, a braided tube, and a fixing member. A tube mounting portion of the spring pusher has a first straight cylinder portion and a tapered cylinder portion. The fixing member is engaged with the tube mounting portion in a state where the braided tube is sandwiched between an outer peripheral surface of the tapered cylinder portion and an inner peripheral surface of the fixing member in the length direction. A length of the first straight cylinder portion is equal to or greater than a mesh spacing of the braided tube.

Description

Technical Field

[0001] This invention relates to the end structure of an optical connector.

[0002] This application claims priority based on Japanese Patent Application No. 2021-068104, filed in Japan on April 14, 2021, the contents of which are incorporated herein by reference. Background Technology

[0003] In the construction of an optical fiber connector, the end of the optical fiber is inserted and installed. To protect the optical fiber extending from the connector, it is inserted through a protective tube inside the tube. Rubber tubes are often used as protective tubes.

[0004] Patent Document 1 discloses a construction in which the end of a protective tube is mounted to the end of an optical connector by inserting the end of the protective tube, which is cylindrical in shape, into the inside of the end of the protective tube. The end of the protective tube is typically fixed to the end of the optical connector using a metal retaining sleeve. More specifically, the protective tube is fixed by clamping the end of the protective tube radially between the end of the optical connector and the retaining sleeve.

[0005] Patent Document 1: Japanese Patent Application Publication No. 2016-218344

[0006] However, braided tubing is sometimes used as a protective tube. Braided tubing is constructed by weaving together fibers that can be bent and deformed (e.g., resin fibers made of polyester). Therefore, braided tubing has the characteristic that its diameter changes significantly compared to rubber tubing when it is stretched or contracted along its axial direction. Consequently, braided tubing has the advantage of being easily applied to various optical fibers with different diameters.

[0007] However, in the method of fixing the braided tube by simply clamping it between the end of the fixed tube and the end of the optical connector, there is a problem that the braided tube is difficult to fix stably due to its characteristic that the diameter size can easily change. Summary of the Invention

[0008] The present invention was made in view of the above-described situation, and its object is to provide an end structure of an optical connector capable of stably fixing a braided tube to the end of an optical connector.

[0009] The first aspect of the present invention relates to an end structure of an optical connector comprising: a ferrule having a connecting end face and an optical fiber hole through which an optical fiber can be inserted; a spring disposed behind the ferrule when the side containing the connecting end face is positioned forward and the opposite side is positioned rearward in the longitudinal direction of the optical fiber hole; a spring pusher that clamps the spring between itself and the ferrule in the longitudinal direction and surrounds the optical fiber; a housing that internally houses the ferrule and the spring, the spring pusher being engaged with the housing to apply a forward force to the ferrule by the spring; a braided tube mounted on the spring pusher; and a fixing member that fixes the braided tube to the spring pusher, the spring pusher having... The tube mounting portion is formed as a cylindrical part extending along the length direction and inserted into the inside of the braided tube. The tube mounting portion has a first straight cylindrical part with a constant outer diameter in the length direction and a tapered cylindrical part located behind the first straight cylindrical part with an outer diameter that decreases as it faces rearward. The fixing member is formed as a cylinder so that the tube mounting portion can be inserted into the tube mounting portion from the rear. The end of the braided tube mounted on the tube mounting portion is located inside the fixing member. The fixing member is engaged with the tube mounting portion in the length direction with the braided tube sandwiched between the outer peripheral surface of the tapered cylindrical part and the inner peripheral surface of the fixing member. The length of the first straight cylindrical part is greater than or equal to the mesh spacing of the braided tube.

[0010] In the end configuration of the aforementioned optical connector, the length of the first cylindrical portion may be more than twice the mesh spacing.

[0011] In the end configuration of the aforementioned optical connector, the outer diameter of the first cylindrical portion may be larger than the inner diameter of the braided tube.

[0012] In the end configuration of the aforementioned optical connector, the tube mounting portion may have a second straight cylindrical portion extending rearward from the aforementioned tapered portion. The outer diameter of the second straight cylindrical portion is constant in the aforementioned length direction and is smaller than the outer diameter of the aforementioned first straight cylindrical portion. When the aforementioned fixing member is locked in the aforementioned tube mounting portion, a gap is formed between the outer peripheral surface of the aforementioned second straight cylindrical portion and the inner peripheral surface of the aforementioned fixing member.

[0013] In the end configuration of the aforementioned optical connector, a gap may be formed between the outer peripheral surface of the first cylindrical portion and the inner peripheral surface of the fixing member when the fixing member is engaged with the tube mounting portion.

[0014] In the end configuration of the aforementioned optical connector, the first radial distance between the outer peripheral surface of the first cylindrical portion and the inner peripheral surface of the fixing member may be less than or equal to the second radial distance between the outer peripheral surface of the second cylindrical portion and the inner peripheral surface of the fixing member.

[0015] In the end configuration of the aforementioned optical connector, the fixing member may have an observation window that radially penetrates the fixing member, and the observation window is disposed at a position corresponding to the outer peripheral surface of the first cylindrical portion in the length direction when the fixing member is locked to the tube mounting portion.

[0016] In the end structure of the aforementioned optical connector, the aforementioned tube mounting portion may have an externally threaded cylindrical portion, which is disposed in front of the aforementioned first cylindrical portion and has an external thread formed on its outer peripheral surface, and an internal thread that engages with the external thread is formed on the inner peripheral surface of the aforementioned fixing member.

[0017] According to the above-described method of the present invention, the braided tube can be stably fixed to the end (tube mounting part) of the optical connector. Attached Figure Description

[0018] Figure 1 This is a perspective view showing the end structure of an optical connector according to one embodiment.

[0019] Figure 2 yes Figure 1 Section II-II view.

[0020] Figure 3 yes Figure 1 An exploded perspective view of the end structure of the optical connector.

[0021] Figure 4 It is Figure 3 An enlarged perspective view of the spring pusher and fixing components.

[0022] Figure 5 It means Figure 3 , Figure 4 A cross-sectional view of the spring pusher, fixing components, and braided tube.

[0023] Figure 6 It means to Figure 5 A cross-sectional view of the fixed component being engaged with the spring pusher.

[0024] Figure 7 It means to Figure 5 A cross-sectional view of the braided tube installed in the spring pusher.

[0025] Figure 8 It means Figure 5 A cross-sectional view of the braided tube being fixed to the spring pusher by a fixing component.

[0026] Figure 9 This is a magnified side view showing an example of a braided tube. Detailed Implementation

[0027] The following is for reference Figures 1-9 An embodiment of the present invention will be described below.

[0028] like Figures 1-3 As shown, the end structure 1 of the optical connector in this embodiment includes multiple optical fibers 2, an optical connector 3, and a braided tube 4. The optical connector 3 includes: a ferrule 10, a housing 20, a connector 30, two guide pins 40, a pin clamping member 50, a spring 60, a spring pushing member 70, a fixing member 80, and a protective cover 90. The optical connector 3 in this embodiment is a so-called MPO (Multi-fiber Push On) type.

[0029] like Figure 2 , Figure 3 As shown, the ends of multiple optical fibers 2 are mounted on optical connector 3. The multiple optical fibers 2 extending from optical connector 3 are inserted into the inside of braided tube 4 and protected. The multiple optical fibers 2 can, for example, be interconnected to form a cored wire, or they can be bundled together by a bundling device.

[0030] The braided tube 4 is mounted on the spring-loaded pusher 70, which will be described later. The braided tube 4 is... Figures 1-3 The diagram is simplified to a simple cylindrical shape. Figures 4-8 Illustrations omitted. (See figure below.) Figure 9 As shown, the actual braided tube 4 is a tube made by weaving elastically flexible fibers 4A and 4B (usually resin fibers) into a mesh. The braided tube 4 has strong elasticity. Therefore, the diameter of the braided tube 4 can be freely varied to match the size (diameter) of the bundle of multiple optical fibers 2 inserted inside the braided tube 4.

[0031] Specifically, the braided tube 4 is composed of multiple first fibers 4A and multiple second fibers 4B. The multiple first fibers 4A are respectively formed in a clockwise spiral shape, and are distributed along the length of the braided tube 4 (axial direction X; in...) Figure 9 The first fibers 4A and second fibers 4B are arranged at equal intervals in the left-right direction. On the other hand, multiple second fibers 4B are formed in a counter-clockwise spiral shape and are arranged at equal intervals in the axial direction X. The first fibers 4A and second fibers 4B interlock at their intersections. Thus, the braided tube 4 has a rhomboid mesh 4C enclosed by two first fibers 4A and two second fibers 4B. The length of the mesh 4C in the axial direction X is varied by extending or contracting the braided tube 4 in the axial direction X, or by changing the diameter of the braided tube 4.

[0032] In the following description, without applying any external force to the braided tube 4, the interval between the joint portion of the first fiber 4A and the second fiber 4B arranged at intervals in the axial X direction (the length of the mesh 4C in the axial X direction) is called the mesh spacing 4P.

[0033] like Figure 1 , Figure 2 As shown, the ferrule 10 has two guide holes 11, multiple fiber optic holes 12, and two limiting protrusions 13. The guide holes 11 and fiber optic holes 12 open at the connection end face 14 of the ferrule 10. Guide pins 40 are inserted into each guide hole 11, and the ends of optical fibers 2 are inserted into each fiber optic hole 12. The number of fiber optic holes 12 in the ferrule 10 can be appropriately varied; for example, it can be only one. That is, the number of optical fibers 2 installed in the optical connector 3 can be one or more.

[0034] (Direction definition)

[0035] In this embodiment, the length direction of the optical fiber 2, guide hole 11, and optical fiber hole 12 is referred to as the axial direction X. The axial direction X is consistent with the length direction of the braided tube 4. The direction in which the two guide holes 11 or the two guide pins 40 are arranged is referred to as the left-right direction Y. The left-right direction Y is orthogonal to the axial direction X. The direction orthogonal to both the axial direction X and the left-right direction Y is referred to as the up-down direction Z. Furthermore, in the axial direction X, the side where the connecting end face 14 is located is referred to as the front (+X side) or the end side, and the opposite side is referred to as the rear (-X side) or the base end side.

[0036] The guide hole 11 and the fiber hole 12 of the ferrule 10 pass through the ferrule 10 in the axial direction X. In addition, the limiting protrusions 13 of the ferrule 10 protrude outward from both ends of the ferrule 10 in the left-right direction Y.

[0037] The end face of the optical fiber 2 inserted into the fiber optic hole 12 is exposed on the connection end face 14 of the ferrule 10. The connection end face 14 can also be tilted relative to the vertical direction Z, for example, in a manner that faces backward as it moves from top to bottom. Such a tilted connection end face 14 can be formed, for example, by grinding the ferrule 10.

[0038] In this embodiment, the insert 10 is formed as a cuboid with a horizontal length where the vertical dimension Z is smaller than the horizontal dimension Y.

[0039] like Figure 2 , Figure 3 As shown, the housing 20 is formed as a cylinder extending along the axial direction X. The housing 20 has openings at both the front and rear. The insert 10 is inserted into the housing 20 from the rear. Figure 2 As shown, with the insert 10 housed inside the housing 20, the limiting protrusion 13 of the insert 10 abuts against the anti-detachment portion 21 formed on the inner side of the housing 20 from the rear. That is, the limiting protrusion 13 of the insert 10 prevents the insert 10 from falling forward from the housing 20. The front end portion of the insert 10, including the connecting end face 14, protrudes forward from the opening at the front end of the housing 20.

[0040] Two locking holes 22 are formed in the housing 20. The locking holes 22 are formed at both ends of the housing 20 in the left-right direction (Y). Figure 2 In the middle, each locking hole 22 penetrates the housing 20 in the left-right direction Y. Alternatively, each locking hole 22 may not penetrate the housing 20, but may be a bottomed recess that is recessed from the inner surface of the housing 20 toward the outer side in the left-right direction Y.

[0041] like Figures 1-3 As shown, the connector 30 is formed as a cylindrical shape extending along the axial direction X and surrounds the housing 20 from the outside. Although detailed description is omitted, the connector 30 is a component that is held by the user and pulled backward when the optical connector 3 is pulled out from the connected object (adapter, etc.).

[0042] A second spring (not shown) is provided between the housing 20 and the connector 30 along the axial direction X. The second spring exerts a force on the connector 30 toward the forward direction and a force on the housing 20 toward the rearward direction. The second spring has the function of restoring the connector 30, which has moved rearward relative to the housing 20, to its forward displacement.

[0043] like Figure 2 , Figure 3 As shown, the pin clamp 50 is positioned behind the insert 10 to hold the rear end of the guide pin 40 that protrudes rearward from the insert 10. The pin clamp 50 has a clamping body 51 and a spring retaining portion 52.

[0044] The clamping body 51 includes two pin retaining portions 53 spaced apart in the left-right direction (Y). Each pin retaining portion 53 retains the rear ends of two guide pins 40. Each guide pin 40, held by the pin retaining portions 53, extends forward in the axial direction (X) towards the clamping body 51. Each guide pin 40 is inserted into the guide hole 11 from the rear of the insert 10, for example, and protrudes forward from the connecting end face 14 of the insert 10. The clamping body 51, holding the two guide pins 40, contacts the insert 10 from the rear, thereby preventing the two guide pins 40 from falling out towards the front of the insert 10. Furthermore, as long as the positional relationship between the base end (base end side) of the insert 10 and the clamping body 51 is fixed, and the pin retaining portion 53 is an elastomer such as rubber, it is also possible to insert the guide pin 40 from the end side (connecting end face 14 side) of the insert 10, embedding and fixing the guide pin 40 to the pin retaining portion 53.

[0045] The spring retaining portion 52 protrudes rearward from the clamping body 51. The spring retaining portion 52 holds the front end of the spring 60, which is disposed behind the pin clamping member 50. Specifically, the spring retaining portion 52 is embedded inside the front end of the cylindrical spring 60. Thus, the front end of the spring 60 is held by the pin clamping member 50.

[0046] Furthermore, a through hole 54 extending along the axial direction X is formed in the pin clamping member 50. The through hole 54 is formed on both the clamping member body 51 and the spring retaining part 52 arranged along the axial direction X. An optical fiber 2 extending rearward from the ferrule 10 is inserted into the through hole 54.

[0047] Spring 60 is disposed behind ferrule 10 and pin holder 50, and is capable of elastic deformation along the axial direction X. Specifically, spring 60 is a cylindrical helical spring that elastically expands and contracts along the axial direction X. An optical fiber 2 is inserted through the inner side of spring 60 behind pin holder 50. Spring 60, ferrule 10, and pin holder 50 are housed together inside housing 20.

[0048] A spring 60 is clamped between a spring pusher 70 and a pin clamp 50 in the axial direction X. The spring pusher 70 is configured to allow the optical fiber 2 to be inserted. Furthermore, the spring pusher 70 is locked to the housing 20. The spring pusher 70 has a spring pusher body 71 and a tube mounting portion 72.

[0049] The spring pusher body 71 has a spring support 73 and two locking tabs 74.

[0050] The spring support 73 supports the spring 60 from the rear. A through hole 731 extending along the axial direction X is formed in the spring support 73. The through hole 731 communicates with the inner side of the cylindrical tube mounting part 72, which will be described later, in the axial direction X. An optical fiber 2 extending rearward from the spring 60 is inserted into the through hole 731 of the spring pusher body 71 and the inner side of the tube mounting part 72.

[0051] Two locking tabs 74 extend forward from the spring support portion 73. Specifically, the two locking tabs 74 extend forward from both ends of the spring support portion 73 in the left-right direction Y. A locking protrusion 741 is formed at the front end of each locking tab 74. Each locking protrusion 741 protrudes from the locking tab 74 outward from the outside of the spring push member 70 in the left-right direction Y.

[0052] like Figure 2 As shown, each locking protrusion 741 engages with the locking hole 22 of the housing 20. Specifically, a pin clamping member 50 and a spring 60 are sandwiched between the spring support 73 and the insert 10 in the axial direction X. Furthermore, when the locking piece 74 is inserted into the housing 20 from the rear, the locking protrusion 741 engages with the locking hole 22 of the housing 20. In this state, the spring 60 elastically compresses and deforms (elastic deformation), and the spring force of the spring 60 applies a force forward to the insert 10.

[0053] like Figure 2 , Figure 3 As shown, the tube mounting portion 72 is formed into a cylindrical shape extending along the axial direction X and through which the optical fiber 2 is inserted. The tube mounting portion 72 extends rearward from the rear end of the aforementioned spring pusher body 71 (spring support portion 73). Figure 2 , Figure 7 As shown, the tube mounting portion 72 is inserted from its rear end into the inner side of the end (front end) of the braided tube 4 in the axial direction X. That is, the end of the braided tube 4 covers the tube mounting portion 72. Thus, the end of the braided tube 4 is mounted to the spring-loaded member 70. Figure 4 , Figure 5 As shown, the pipe mounting section 72 has a first straight cylindrical section 75, a tapered cylindrical section 76, a second straight cylindrical section 77, and an externally threaded cylindrical section 78.

[0054] like Figure 5 As shown, the outer diameter 75D of the first cylindrical section 75 is constant in the axial direction X. The outer diameter 75D of the first cylindrical section 75 is larger than the inner diameter 4D of the braided tube 4 under the condition of no external force.

[0055] The length 75L of the first straight cylindrical section 75 in the axial direction X is equal to the mesh spacing 4P of the braided tube 4 (refer to...). Figure 9 The length 75L of the first cylindrical portion 75 is more preferably more than twice the mesh pitch 4P. In addition, in order to avoid the optical connector 3 becoming too large (especially its length in the axial direction X), the length 75L of the first cylindrical portion 75 is preferably less than, for example, three times the mesh pitch 4P.

[0056] The tapered portion 76 extends rearward from the rear end of the first straight portion 75. The outer diameter of the tapered portion 76 decreases as it extends rearward from the rear end of the first straight portion 75. In other words, the outer circumferential surface of the tapered portion 76 is inclined relative to the axial direction X. Therefore, the outer circumferential surface (tapered outer surface) of the tapered portion 76 faces not only radially outward but also rearward (-X side).

[0057] The outer diameter of the tapered portion 76 at its front end (on the side of the first straight portion 75) is equal to the outer diameter 75D of the first straight portion 75. On the other hand, the outer diameter of the tapered portion 76 at its rear end (on the side of the second straight portion 77) is smaller than the outer diameter of the tapered portion 76 at its front end, and is equal to the outer diameter 77D of the second straight portion 77.

[0058] The second straight cylindrical portion 77 extends rearward from the rear end of the tapered cylindrical portion 76. The outer diameter 77D of the second straight cylindrical portion 77 is constant in the axial direction X and is smaller than the outer diameter 75D of the first straight cylindrical portion 75. The outer diameter 77D of the second straight cylindrical portion 77 can be, for example, the same as or slightly smaller than the inner diameter 4D of the braided tube 4. In this embodiment, the outer diameter 77D of the second straight cylindrical portion 77 is slightly larger than the inner diameter 4D of the braided tube 4. Figure 7As shown, if the second straight section 77 is inserted into the inside of the braided tube 4, the portion of the braided tube 4 corresponding to the second straight section 77 will deform slightly. The diameter of this portion of the braided tube 4 will hardly change compared to its diameter when no external force is applied to it.

[0059] like Figures 4-6 As shown, the externally threaded cylindrical portion 78 is used to engage the fixing member 80 (described later) with the pipe mounting portion 72. The externally threaded cylindrical portion 78 is configured to connect to the front of the first straight cylindrical portion 75. An external thread 781 is formed on the outer circumferential surface of the externally threaded cylindrical portion 78. The outer diameter of the externally threaded cylindrical portion 78 is larger than the outer diameter 75D of the first straight cylindrical portion 75. The externally threaded cylindrical portion 78, the first straight cylindrical portion 75, the tapered cylindrical portion 76, and the second straight cylindrical portion 77 are arranged sequentially from the rear end of the spring pusher body 71 (spring support portion 73) rearward. Figure 7 As shown, the end of the braided tube 4 covers the first straight section 75, the tapered section 76, and the second straight section 77, but does not cover the externally threaded section 78.

[0060] The inner diameter of the tube mounting portion 72, which includes the externally threaded cylindrical portion 78, the first straight cylindrical portion 75, the tapered cylindrical portion 76, and the second straight cylindrical portion 77, is constant in the axial direction X. The inner diameter of the tube mounting portion 72 is set according to the thickness and number of optical fibers 2 inserted into the tube mounting portion 72.

[0061] like Figure 2 , Figure 8 As shown, the fixing component 80 secures the braided tube 4, which is temporarily fixed to the tube mounting portion 72 of the spring pusher 70, relative to the tube mounting portion 72. Figure 4 , Figure 5 As shown, the fixing member 80 is formed as a cylinder extending along the axial direction X. (As shown...) Figure 8 As shown, the tube mounting portion 72 and the end of the braided tube 4 mounted on the tube mounting portion 72 are inserted into the inner side of the cylindrical fixing member 80 from the rear of the tube mounting portion 72. The fixing member 80 is configured to lock into the tube mounting portion 72 with the braided tube 4 sandwiched between the outer peripheral surface of the tapered portion 76 and the inner peripheral surface of the fixing member 80 in the axial direction X.

[0062] The fixing component 80 of this embodiment will be described in detail below.

[0063] like Figure 5 , Figure 6As shown, an internal thread 81 is formed on the inner circumferential surface of the fixing member 80 for engaging the fixing member 80 with the pipe mounting portion 72. The internal thread 81 engages with the external thread 781 of the pipe mounting portion 72. The internal thread 81 is located at the front end of the fixing member 80. Furthermore, the inner circumferential surface of the fixing member 80 includes a first straight inner surface 82, a tapered inner surface 83, and a second straight inner surface 84 arranged sequentially from the rear end of the internal thread 81 to the rear.

[0064] The diameter of the first inner surface 82 (the inner diameter of the fixed component 80 in the first inner surface 82) is constant in the axial direction X. For example... Figure 6 As shown, the first inner surface 82 faces the outer peripheral surface of the first cylindrical portion 75 radially when the fixing member 80 is engaged with the tube mounting portion 72. A gap is formed between the first inner surface 82 and the outer peripheral surface of the first cylindrical portion 75 when the fixing member 80 is engaged with the tube mounting portion 72.

[0065] The radial distance D1 (first distance) between the first inner surface 82 and the outer peripheral surface of the first cylindrical portion 75 can be, for example, formed by fibers 4A, 4B (see reference) of the braided tube 4. Figure 9 The diameter of the fiber can be the same as that of fiber 4A or 4B, or it can be larger than the diameter of fiber 4A or 4B.

[0066] like Figure 5 , Figure 6 As shown, the diameter of the tapered inner surface 83 (the inner diameter of the fixing member 80 within the tapered inner surface 83) decreases as it moves rearward from the rear end of the first straight inner surface 82. In other words, the tapered inner surface 83 is inclined relative to the axial direction X. Therefore, the tapered inner surface 83 faces not only radially inward towards the fixing member 80 but also forward (towards the +X side). The diameter of the tapered inner surface 83 at its front end (on the side of the first straight inner surface 82) is equal to the diameter of the first straight inner surface 82. On the other hand, the diameter of the tapered inner surface 83 at its rear end (on the side of the second straight inner surface 84) is equal to the diameter of the second straight inner surface 84.

[0067] like Figure 6 As shown, with the fixing member 80 engaged with the tube mounting portion 72, the conical inner surface 83 faces the outer peripheral surface of the conical cylinder portion 76 radially and axially (X). With the fixing member 80 engaged with the tube mounting portion 72, the distance between the conical inner surface 83 and the outer peripheral surface of the conical cylinder portion 76 in the axial direction (X) is preferably less than the diameter of the fibers 4A and 4B forming the braided tube 4. Furthermore, with the fixing member 80 engaged with the tube mounting portion 72, for example, the conical inner surface 83 may also contact the outer peripheral surface of the conical cylinder portion 76. The inclination angles of the conical inner surface 83 and the outer peripheral surface of the conical cylinder portion 76 relative to the axial direction (X) may, for example, be different from each other, but in this embodiment they are equal.

[0068] like Figure 8 As shown, if the fixing member 80 is engaged with the tube mounting portion 72 while the braided tube 4 covers the tube mounting portion 72, the braided tube 4 is fixed to the tube mounting portion 72. More specifically, the braided tube 4 mounted on the tube mounting portion 72 is clamped between the tapered inner surface 83 of the fixing member 80 and the outer peripheral surface of the tapered portion 76 in the axial direction X.

[0069] like Figure 5 , Figure 6 As shown, the diameter of the second straight inner surface 84 (the inner diameter of the fixed component 80 in the second straight inner surface 84) is constant in the axial direction X. Figure 6 As shown, the second straight inner surface 84 faces the outer peripheral surface of the second straight cylindrical portion 77 radially when the fixing member 80 is engaged with the tube mounting portion 72. When the fixing member 80 is engaged with the tube mounting portion 72, a gap is formed between the second straight inner surface 84 and the outer peripheral surface of the second straight cylindrical portion 77.

[0070] The radial distance D2 (second distance) between the second inner surface 84 and the outer peripheral surface of the second cylindrical portion 77 is greater than or equal to the radial distance D1 between the first inner surface 82 and the outer peripheral surface of the first cylindrical portion 75. The distance D2 between the second inner surface 84 and the outer peripheral surface of the second cylindrical portion 77 is preferably more than twice the diameter of the fibers 4A and 4B forming the braided tube 4.

[0071] To maximize the distance D2 between the second inner surface 84 and the outer peripheral surface of the second cylindrical portion 77, it is necessary to reduce the outer diameter 77D of the second cylindrical portion 77. However, reducing the outer diameter 77D results in an excessively thinner wall thickness for the second cylindrical portion 77, which reduces its strength. Therefore, the distance D2 between the second inner surface 84 and the outer peripheral surface of the second cylindrical portion 77 is preferably set to a level that ensures the strength of the second cylindrical portion 77. For example, the distance D2 between the second inner surface 84 and the outer peripheral surface of the second cylindrical portion 77 is preferably less than three times the diameter of the fibers 4A and 4B forming the braided tube 4.

[0072] like Figure 4 , Figure 5 As shown, the fixing member 80 of this embodiment further has an observation window 85 that radially penetrates the fixing member 80. The observation window 85 is formed at a location on the fixing member 80 that corresponds to the first inner surface 82 in the axial direction X. Thus, as Figure 6 As shown, with the fixing member 80 engaged with the tube mounting portion 72, the observation window 85 is positioned in the axial direction X, corresponding to the outer peripheral surface of the first straight cylindrical portion 75. Therefore, with the fixing member 80 engaged with the tube mounting portion 72, the outer peripheral surface of the first straight cylindrical portion 75 can be viewed from the outside of the fixing member 80 through the observation window 85.

[0073] In this embodiment, a plurality of observation windows 85 are arranged at circumferential intervals around the fixing member 80. Furthermore, knurling is formed on the outer peripheral surface of the fixing member 80. This knurling prevents slippage when the operator rotates the fixing member 80. The radially outer end of the observation window 85 has an opening in the knurling. However, knurling may not be formed on the fixing member 80.

[0074] like Figure 2 , Figure 3 As shown, the protective cover 90 is formed as a cylinder extending along the axial direction X. The tube mounting portion 72 and the fixing member 80, which is locked to the tube mounting portion 72, are inserted into the inner side of the protective cover 90 from the rear of the fixing member 80. Furthermore, an optical fiber 2 and a braided tube 4 extending towards the rear of the tube mounting portion 72 and the fixing member 80 are inserted into the inner side of the protective cover 90. The protective cover 90 protects the tube mounting portion 72 and the fixing member 80 inserted within the protective cover 90. The protective cover 90 prevents the fixing member 80 from accidentally rotating relative to the tube mounting portion 72, thus disengaging (loosening) the locking state of the fixing member 80 relative to the tube mounting portion 72.

[0075] In the end structure 1 of the optical connector in this embodiment, the following is mainly referred to Figures 7-8 An example of a method for fixing the braided tube 4 to the spring pusher 70 will be described.

[0076] First, such as Figure 7 As shown, the tube mounting portion 72 of the spring pusher 70 is inserted into the inner side of the end of the braided tube 4. At this time, the braided tube 4 covers the second straight tube portion 77, the tapered tube portion 76, and the first straight tube portion 75 from the rear in sequence.

[0077] Here, although the outer diameter 77D of the second straight section 77 is larger than the inner diameter 4D of the braided tube 4, the difference is small. Therefore, the second straight section 77 can be easily inserted into the inside of the braided tube 4. Furthermore, if the outer diameter 77D of the second straight section 77 is less than or equal to the inner diameter 4D of the braided tube 4, the second straight section 77 can be inserted into the inside of the braided tube 4 even more easily.

[0078] Furthermore, a tapered section 76 and a first straight section 75 are arranged sequentially in front of the second straight section 77. Therefore, even if the outer diameter 75D of the first straight section 75 is larger than the inner diameter 4D of the braided tube 4, the first straight section 75 can be easily inserted into the inner side of the end of the braided tube 4 through the tapered section 76. More specifically, by moving the braided tube 4 forward, the inner diameter of the braided tube 4 expands along the outer circumferential surface of the tapered section 76.

[0079] With the first cylindrical portion 75 inserted inside the end of the braided tube 4, the braided tube 4 elastically deforms such that the diameter of the portion of the braided tube 4 corresponding to the first cylindrical portion 75 increases. That is, the elasticity of the braided tube 4 holds (temporarily fixes) the end of the braided tube 4 to the outer circumferential surface of the first cylindrical portion 75. Furthermore, in this state, the mesh 4C of the braided tube 4 (refer to…) Figure 8 The fibers 4A and 4B of the braided tube 4 in the outer peripheral surface of the first cylindrical portion 75 expand circumferentially, so the density of the fibers 4A and 4B in the first cylindrical portion 75 is less than the density of the fibers 4A and 4B in the state without external force.

[0080] Furthermore, with the tube mounting part 72 inserted inside the end of the braided tube 4, the braided tube 4 is also disposed on the outer peripheral surface of the tapered part 76.

[0081] After inserting the tube mounting part 72 into the inside of the end of the braided tube 4, as follows: Figure 8 As shown, the tube mounting portion 72 and the end of the braided tube 4 are inserted into the inner side of the fixing member 80, and the fixing member 80 is locked to the tube mounting portion 72. In this embodiment, the fixing member 80 is locked to the tube mounting portion 72 by rotating the fixing member 80 relative to the tube mounting portion 72, causing the internal thread 81 of the fixing member 80 to engage with the external thread 781 of the tube mounting portion 72. By rotating the fixing member 80 with the internal thread 81 engaged with the external thread 781, the fixing member 80 moves forward relative to the tube mounting portion 72. Therefore, a portion of the braided tube 4 is clamped between the tapered inner surface 83 of the fixing member 80 and the outer peripheral surface of the tapered portion 76 in the axial direction X. Thus, the braided tube 4 is fixed to the tube mounting portion 72 of the spring-loaded member 70.

[0082] As explained above, in the end configuration 1 of the optical connector in this embodiment, by locking the fixing member 80 to the tube mounting portion 72, the braided tube 4 mounted on the tube mounting portion 72 is clamped in the axial direction X between the outer peripheral surface of the tapered portion 76 of the tube mounting portion 72 and the tapered inner surface 83 of the fixing member 80. Therefore, the braided tube 4 can be stably fixed relative to the tube mounting portion 72 (the end of the optical connector 3).

[0083] Furthermore, in this embodiment, the outer diameter 75D of the first straight cylindrical portion 75 of the tube mounting portion 72 is larger than the inner diameter 4D of the braided tube 4 when no external force is applied. Therefore, when the end of the braided tube 4 covers the first straight cylindrical portion 75, the braided tube 4 elastically deforms in such a way that the diameter of the braided tube 4 increases. Here, the length 75L of the first straight cylindrical portion 75 is greater than or equal to the mesh spacing 4P of the braided tube 4, thereby allowing the braided tube 4 to be stably held (temporarily fixed) by utilizing the elasticity of the braided tube 4 and passing through the first straight cylindrical portion 75. Furthermore, if the length 75L of the first straight cylindrical portion 75 is more than twice the mesh spacing 4P of the braided tube 4, the braided tube 4 can be held more stably by the first straight cylindrical portion 75. Therefore, it is possible to prevent the end of the braided tube 4 from detaching from the tube mounting portion 72 during the period from when the end of the braided tube 4 covers the first straight cylindrical portion 75 to when the braided tube 4 is sandwiched between the outer peripheral surface of the tapered cylindrical portion 76 and the tapered inner surface 83 of the fixing member 80.

[0084] Furthermore, in this embodiment, when the fixing member 80 is engaged with the tube mounting portion 72, a gap is formed between the outer peripheral surface of the second straight section 77 and the second straight inner surface 84 (inner peripheral surface) of the fixing member 80. This prevents the braided tube 4 from being trapped between the outer peripheral surface of the second straight section 77 and the second straight inner surface 84. In particular, by making the distance D2 between the outer peripheral surface of the second straight section 77 and the second straight inner surface 84 more than twice the diameter of the fibers 4A and 4B of the braided tube 4, the trapping of the braided tube 4 between the outer peripheral surface of the second straight section 77 and the second straight inner surface 84 can be prevented more reliably. Therefore, when the fixing member 80 is engaged with the tube mounting portion 72 by threads (external thread 781 and internal thread 81), even if the fixing member 80 rotates relative to the tube mounting portion 72, the twisting of the braided tube 4 due to rotation with the fixing member 80 can be prevented.

[0085] Furthermore, in this embodiment, with the fixing member 80 engaged with the tube mounting portion 72, a gap is formed between the outer peripheral surface of the first cylindrical portion 75 and the first straight inner surface 82 (inner peripheral surface) of the fixing member 80. This prevents the braided tube 4 from being trapped between the outer peripheral surface of the first cylindrical portion 75 and the first straight inner surface 82. Therefore, when the fixing member 80 is engaged with the tube mounting portion 72 by the threads (the external thread 781 of the tube mounting portion 72 and the internal thread 81 of the fixing member 80), even if the fixing member 80 is rotated relative to the tube mounting portion 72, the situation where the braided tube 4 rotates together with the fixing member 80 and twists is prevented.

[0086] Furthermore, it is preferable that the distance D1 between the outer peripheral surface of the first straight cylindrical portion 75 and the first straight inner surface 82 is smaller than the distance D2 between the outer peripheral surface of the second straight cylindrical portion 77 and the second straight inner surface 84. For example, the distance D1 can also be equal to the diameter of the fibers 4A and 4B of the braided tube 4. In these cases, even if the braided tube 4 is sandwiched between the outer peripheral surface of the first straight cylindrical portion 75 and the first straight inner surface 82, it is possible to prevent the braided tube 4 from rotating together with the fixing member 80.

[0087] To explain this further, the braided tube 4 covering the first cylindrical portion 75 elastically deforms by increasing its diameter, thereby reducing the density of fibers 4A and 4B of the braided tube 4 on the outer circumferential surface of the first cylindrical portion 75. Therefore, even when the braided tube 4 is sandwiched between the first cylindrical portion 75 and the fixing member 80, the friction between the fixing member 80 and the braided tube 4 as the fixing member 80 rotates is reduced compared to before the diameter of the braided tube 4 increased. Thus, it is possible to suppress the situation where the braided tube 4 rotates along with the fixing member 80.

[0088] Furthermore, in this embodiment, the fixing member 80 is provided with an observation window 85, which allows the outer peripheral surface of the first cylindrical portion 75 to be viewed from the outside of the fixing member 80 when the fixing member 80 is engaged with the tube mounting portion 72. Therefore, it is possible to easily determine whether the braided tube 4 is fixed relative to the tube mounting portion 72 using the observation window 85.

[0089] Specifically, when the fixing member 80 is engaged with the tube mounting portion 72, and the braided tube 4 can be seen through the observation window 85 to be located on the outer peripheral surface of the first straight cylindrical portion 75, it can be determined that the braided tube 4 is sandwiched between the outer peripheral surface of the conical portion 76 and the conical inner surface 83 of the fixing member 80, that is, the braided tube 4 is fixed relative to the tube mounting portion 72. On the other hand, when the fixing member 80 is engaged with the tube mounting portion 72, and the braided tube 4 cannot be seen through the observation window 85 to be located on the outer peripheral surface of the first straight cylindrical portion 75, it can be determined that the braided tube 4 is not sandwiched between the outer peripheral surface of the conical portion 76 and the conical inner surface 83 of the fixing member 80, that is, the braided tube 4 is not fixed relative to the tube mounting portion 72.

[0090] Furthermore, according to this embodiment, an external thread 781 is formed in the tube mounting portion 72, and an internal thread 81 that engages with the external thread 781 is formed in the fixing member 80. Therefore, by engaging the internal thread 81 of the fixing member 80 with the external thread 781 of the tube mounting portion 72, the fixing member 80 can be easily secured to the tube mounting portion 72. Furthermore, with the internal thread 81 of the fixing member 80 engaged with the external thread 781 of the tube mounting portion 72, rotating the fixing member 80 relative to the tube mounting portion 72 allows the tapered inner surface 83 of the fixing member 80 to approach the outer peripheral surface of the tapered portion 76 in the axial direction X. That is, simply rotating the fixing member 80 relative to the tube mounting portion 72 allows the braided tube 4 to be easily clamped between the outer peripheral surface of the tapered portion 76 and the inner peripheral surface of the fixing member 80. Furthermore, by engaging the internal thread 81 with the external thread 781, the force exerted by the operator to rotate the fixing member 80 is amplified and becomes a propulsive force for the fixing member 80. Therefore, the force on the axial direction X of the braided tube 4 clamped by the conical inner surface 83 and the conical cylinder 76 increases, thereby enabling the braided tube 4 to be fixed more stably.

[0091] The above describes the embodiments, but the present invention is not limited to the embodiments described above, and various modifications can be made without departing from the spirit of the present invention.

[0092] For example, the outer diameter 75D of the first cylindrical portion 75 may be 4D or less, which is the inner diameter of the braided tube 4 when no external force is applied. In this case, the braided tube 4 installed in the tube mounting portion 72 can be clamped in the axial direction X between the outer peripheral surface of the tapered portion 76 of the tube mounting portion 72 and the inner peripheral surface of the fixing member 80.

[0093] Furthermore, the structure for securing the fixing member 80 to the tube mounting portion 72 is not limited to a threaded structure (external thread 781 and internal thread 81). For example, it may also be composed of a claw formed on the inner periphery of the fixing member 80 and a recess formed on the outer periphery of the tube mounting portion 72 for the claw of the fixing member 80 to enter and hook.

[0094] Furthermore, the component forming the external thread 781 (external threaded cylinder 78) and the component forming the internal thread 81 (fixed component 80) may be made of materials with different glass contents, and thus have different elastic moduli. In this case, it is possible to suppress or prevent the loosening of the threads (loosening of the meshing between the external thread 781 and the internal thread 81) caused by external factors such as vibration.

[0095] Furthermore, the constituent elements in the above embodiments can be appropriately replaced with known constituent elements, and the above embodiments and variations can also be appropriately combined.

[0096] Explanation of reference numerals in the attached figures

[0097] 1...End structure of optical connector; 2...Optical fiber; 3...Optical connector; 4...Braided tube; 4D...Inner diameter of braided tube 4; 4P...Mesh spacing; 10...Flange; 14...Connecting end face; 20...Housing; 60...Spring; 70...Spring pusher; 72...Tube mounting part; 75...First straight cylinder part; 75D...Outer diameter of first straight cylinder part 75; 75L...Length of first straight cylinder part 75; 76...Conical cylinder part; 77...Second straight cylinder part; 77D...Outer diameter of second straight cylinder part 77; 78...Externally threaded cylinder part; 781...External thread; 80...Fixing component; 81...Internal thread; 85...Observation window; D1...First gap; D2...Second gap; X...Axial direction (length direction of fiber optic hole).

Claims

1. An end structure of an optical connector, characterized in that, have: A ferrule, the ferrule having a connection end face and an optical fiber hole for inserting an optical fiber into the connection end face; A spring is disposed at the rear of the ferrule when the side containing the connection end face is set as the front and the opposite side is set as the rear in the longitudinal direction of the optical fiber hole. A spring-loaded member, which clamps the spring between itself and the ferrule in the longitudinal direction and surrounds the optical fiber; A housing that internally houses the insert and the spring, the spring pusher being engaged with the housing to cause the insert to be forced forward by the spring; Braided tubing, the braided tubing being mounted on the spring pusher; as well as The fixing component secures the braided tube to the spring pusher. The spring pusher has a tube mounting portion, which is formed as a cylinder extending along the length direction and inserted into the inside of the braided tube. The pipe mounting section has a first straight cylindrical section with a constant outer diameter in the length direction, and a tapered section located behind the first straight cylindrical section whose outer diameter decreases as it moves rearward. The fixing component is formed in a cylindrical shape so that the tube mounting part can be inserted into it from the rear. The end of the braided tube installed in the tube mounting part is located inside the fixing component. The fixing component is engaged with the tube mounting portion in the longitudinal direction with the braided tube clamped between the outer circumferential surface of the conical portion and the inner circumferential surface of the fixing component. The length of the first straight section is greater than or equal to the mesh spacing of the braided tube.

2. The end structure of the optical connector according to claim 1, characterized in that, The length of the first straight section is more than twice the mesh spacing.

3. The end structure of the optical connector according to claim 1 or 2, characterized in that, The outer diameter of the first straight section is larger than the inner diameter of the braided tube.

4. The end structure of the optical connector according to any one of claims 1 to 3, characterized in that, The pipe mounting portion has a second straight cylindrical portion extending rearward from the conical portion. The outer diameter of the second straight cylindrical portion is constant in the length direction and is smaller than the outer diameter of the first straight cylindrical portion. When the fixing component is engaged with the pipe mounting portion, a gap is formed between the outer peripheral surface of the second straight section and the inner peripheral surface of the fixing component.

5. The end structure of the optical connector according to claim 4, characterized in that, When the fixing component is engaged with the tube mounting portion, a gap is formed between the outer peripheral surface of the first straight section and the inner peripheral surface of the fixing component.

6. The end structure of the optical connector according to claim 5, characterized in that, The first radial distance between the outer peripheral surface of the first straight cylindrical portion and the inner peripheral surface of the fixing member is less than or equal to the second radial distance between the outer peripheral surface of the second straight cylindrical portion and the inner peripheral surface of the fixing member.

7. The end structure of the optical connector according to any one of claims 1 to 6, characterized in that, The fixing component has an observation window that extends radially through the fixing component. The observation window is positioned in the length direction corresponding to the outer periphery of the first straight section when the fixing component is engaged with the pipe mounting portion.

8. The end structure of the optical connector according to any one of claims 1 to 7, characterized in that, The pipe mounting portion has an externally threaded cylindrical portion, which is located in front of the first straight cylindrical portion and has external threads formed on its outer circumferential surface. An internal thread that engages with the external thread is formed on the inner circumferential surface of the fixing component.

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