Adapter and optical connection structure

Abstract

The purpose of the present invention is to provide an adapter and an optical connection structure, the adapter being capable of appropriately connecting two types of optical connectors each having a different biasing force toward a ferrule.　An adapter (2) according to the present invention comprises: a first insertion port (18) through which a first housing (120) of a first optical connector (100) can be inserted; a second insertion port (25) through which a second housing (220) of a second optical connector (200) can be inserted and which opens in a direction opposite from the first insertion port (18); and a connection opening (14) which is disposed between the first insertion port (18) and the second insertion port (25) and through which the second ferrule (210) is insertably connected. The connection opening (14) has a shape restricting insertion of the first ferrule (110).

Description

Adapter and optical connection structure

[0001] This application claims priority to Japanese Patent Application No. 2023-034604, filed on March 7, 2023, the contents of which are incorporated herein by reference.

[0002] Patent Document 1 discloses an optical connection structure that connects two optical connectors using an adapter. In this optical connection structure, a good connection state is maintained by pressing the connection end faces of the ferrules of each optical connector together with an appropriate biasing force. The biasing force is generated by a biasing member biasing the ferrules within the housing of each optical connector.

[0003] Japanese Patent Application Publication No. 9-304655

[0004] The biasing force applied to the ferrules may differ depending on the type of optical connector. In other words, when connecting different types of optical connectors, the biasing force applied to each ferrule may differ. If the biasing force applied to each ferrule differs, the ferrules may be positioned in an inappropriate position (a position other than the predetermined mating surface). Specifically, a ferrule with a larger biasing force may be pushed into a ferrule with a smaller biasing force. As a result, a problem may arise in which a good connection state cannot be maintained.

[0005] The present invention has been made in consideration of the above circumstances, and aims to provide an adapter and an optical connection structure that can properly connect two types of optical connectors that have different biasing forces on the ferrules.

[0006] In order to solve the above problem, aspect 1 of the present invention is an adapter that connects a first optical connector having a first housing that holds a first ferrule having a first connecting end face therein, and a second optical connector having a second housing that holds a second ferrule having a second connecting end face that has a smaller area than the first connecting end face, the adapter having a first insertion port through which the first housing can be inserted, a second insertion port through which the second housing can be inserted and that opens in the direction opposite to the first insertion port, and a connection opening that is positioned between the first insertion port and the second insertion port and through which the second ferrule can be inserted, the connection opening having a shape that limits the insertion of the first ferrule.

[0007] Aspect 2 of the present invention is an adapter according to aspect 1, which comprises a first member having the first insertion port and a second member having the second insertion port, and the first member and the second member may be fixed together.

[0008] Aspect 3 of the present invention is an adapter according to aspect 1, comprising an outer housing having the first insertion port and the second insertion port, an inner plate housed in the outer housing and having the connection opening, and an elastic member that urges the inner plate toward the first connection end face, wherein the inner plate has a first abutment surface against which the first ferrule abuts, and the elastic member may be compressed between the outer housing and the inner plate.

[0009] A fourth aspect of the present invention is an adapter according to the third aspect, wherein the second optical connector is provided with a locking protrusion, the outer housing is provided with a locking hole into which the locking protrusion engages, and the dimension from the rear end of the locking hole to the opposing surface opposite the first abutment surface of the inner plate may be greater than the dimension from the portion of the locking protrusion that contacts the locking hole to the tip surface of the second housing.

[0010] Aspect 5 of the present invention is an adapter according to aspect 3 or 4, wherein the outer housing may have a first outer housing member and a second outer housing member, and the inner plate may be disposed within a space formed by the first outer housing member and the second outer housing member.

[0011] An optical connection structure according to a sixth aspect of the present invention may include the adapter according to any one of the first to fifth aspects, the first optical connector, and the second optical connector.

[0012] A seventh aspect of the present invention is an optical connection structure according to the sixth aspect, wherein the first optical connector has a first biasing member that biases the first ferrule, and the second optical connector has a second biasing member that biases the second ferrule, and when the first ferrule and the second ferrule are in contact, the biasing force of the first ferrule by the first biasing member may be within a range of 18 to 22 N, and the biasing force of the second ferrule by the second biasing member may be within a range of 7 to 13 N.

[0013] Aspect 8 of the present invention is an optical connection structure related to aspect 7, wherein the first optical connector has a protrusion, the adapter has an abutment portion adjacent to the connection opening and abutting the first connection end face, and a locking portion that locks onto the protrusion, and in the axial direction in which the first optical connector and the second optical connector face each other, the distance between the abutment portion and the locking portion may be set so that the biasing force of the first ferrule by the first biasing member is within the range of 18 to 22 N.

[0014] According to the adapter and optical connection structure of the above aspects of the present invention, two types of optical connectors that have different biasing forces on the ferrules can be properly connected to each other.

[0015] 1 is a perspective view of an optical connection structure according to a first embodiment. FIG. 1 is a perspective view of the first optical connector of FIG. 1. FIG. 2 is a perspective view of the second optical connector of FIG. 1. FIG. 3 is a view of the first member of the adapter of FIG. 1 as seen from the first optical connector side. FIG. 4 is a cross-sectional view taken along the arrows V-V of FIG. 4. FIG. 1 is a cross-sectional view taken along the arrows VI-VI of FIG. 1. FIG. 1 is a cross-sectional view taken along the arrows VII-VII of FIG. 1. FIG. 3 is a cross-sectional view of a main part of an optical connection structure according to a second embodiment. FIG. 4 is a cross-sectional view of a main part of an optical connection structure according to a second embodiment. FIG. 8 is a perspective view of the first main body of FIG. 8. FIG. 9 is a perspective view of the second main body of FIG. 8. FIG. 9 is a perspective view of the inner plate of FIG. 8. FIG. 10 is a perspective view of the adapter of FIG. 8. FIG. 11 is a cross-sectional view of a main part of the adapter of FIG. 8.

[0016] First Embodiment An adapter and an optical connection structure according to a first embodiment will now be described with reference to the drawings. As shown in Fig. 1, the optical connection structure 1 includes a first optical connector 100, a second optical connector 200, and an adapter 2. As shown in Fig. 2, the first optical connector 100 includes a first ferrule 110 having a first connection end face 111, and a first housing 120 that holds the first ferrule 110 therein. A plurality of optical fibers F1 (first optical fibers) are exposed at the first connection end face 111.

[0017] 3, the second optical connector 200 includes a second ferrule 210 having a second connecting end face 211 and a second housing 220 that holds the second ferrule 210 therein. A plurality of optical fibers F2 (second optical fibers) are exposed at the second connecting end face 211. The adapter 2 has a function of maintaining the first connecting end face 111 and the second connecting end face 211 in contact with each other at appropriate positions. This allows the optical connection structure 1 to optically connect a plurality of optical fibers F1 and a plurality of optical fibers F2.

[0018] As shown in Fig. 3, the second optical connector 200 has two positioning pins 260. As shown in Fig. 2, the first optical connector 100 has two first positioning holes 113. The relative positions of the first optical connector 100 and the second optical connector 200 are determined by inserting the positioning pins 260 into the first positioning holes 113. In this embodiment, the first optical connector 100 is described as the female side and the second optical connector 200 is described as the male side. However, the first optical connector 100 may be the male side and the second optical connector 200 may be the female side. In other words, the first optical connector 100 may be provided with positioning pins, and the second optical connector 200 may not be provided with positioning pins.

[0019] (Directional Definition) As shown in FIG. 1 , the direction in which the first connecting end face 111 of the first optical connector 100 and the second connecting end face 211 of the second optical connector 200 face each other is referred to as the axial direction Z. In the axial direction Z, the side from the second optical connector 200 toward the first optical connector 100 (the +Z side) is referred to as the "first optical connector side" or the "base end side of the first optical connector." The opposite side (the -Z side) is referred to as the "second optical connector side" or the "base end side of the second optical connector." A direction perpendicular to the axial direction Z is referred to as the first orthogonal direction X. The first orthogonal direction X is also the direction in which the optical fibers F1 and F2 are arranged on the connecting end faces 111 and 211 (see FIGS. 2 and 3 ). A direction perpendicular to both the axial direction Z and the first orthogonal direction X is referred to as the second orthogonal direction Y. One side of the first orthogonal direction X is referred to as the +X side, and the other side is referred to as the -X side. One side in the second orthogonal direction Y is referred to as the +Y side, and the other side is referred to as the −Y side.

[0020] As shown in Figure 1, the adapter 2 of this embodiment has a first member 10 and a second member 20. The first member 10 is located on the +Z side, and the second member 20 is located on the -Z side. The adapter 2 is formed by combining these two members 10 and 20. However, the adapter 2 may also be a single member.

[0021] 4 and 5 , the first member 10 has a first main body 11, a protrusion 12, a contact portion 13, two first flanges 15, and two locking pieces 17. The first main body 11 is cylindrical and extends in the axial direction Z. In this embodiment, the first housing 120 has a substantially rectangular parallelepiped shape, and accordingly, the first main body 11 is also rectangular cylindrical (see FIGS. 1 and 2 ). However, the shapes of the first main body 11 and the first housing 120 can be changed.

[0022] As shown in FIG. 5, a first insertion opening 18 is provided at the end on the +Z side of the first main body 11. The first insertion opening 18 opens toward the +Z side. When connecting the optical connectors 100 and 200 using the adapter 2, the first optical connector 100 is inserted into the adapter 2 through the first insertion opening 18. A connection opening 14 is provided at the end on the -Z side of the first main body 11. The connection opening 14 is used to bring the two ferrules 110 and 210 into contact with each other. As shown in FIG. 4, the dimension (width) of the connection opening 14 in the second orthogonal direction Y is referred to as a third dimension L3.

[0023] As shown in FIG. 5, the protrusion 12 protrudes from the first main body portion 11 toward the -Z side. The connection opening 14 is located inside the protrusion 12. However, the protrusion 12 may be omitted. The abutting portion 13 protrudes toward the inside of the connection opening 14. The shape of the abutting portion 13 corresponds to the shape of the first connection end face 111. In this embodiment, as shown in FIG. 2, the first connection end face 111 is substantially rectangular. Therefore, as shown in FIG. 4, the abutting portion 13 has a square frame shape. The abutting portion 13 abuts along the outer periphery of the first connection end face 111. The abutting portion 13 has an abutting surface 13a facing the +Z side. The first connection end face 111 abuts against this abutting surface 13a. However, the shapes of the first connection end face 111 and the abutting portion 13 can be changed.

[0024] As shown in Fig. 4, the two first flange portions 15 protrude from the first main body portion 11 toward the +X side and the -X side. The first flange portions 15 are used to fasten the first member 10 and the second member 20 together. A first fixing hole 16 is formed in each of the two first flange portions 15. As shown in Fig. 5, the first fixing hole 16 has a small diameter portion 16a and a large diameter portion 16b. The large diameter portion 16b has an inner diameter larger than that of the small diameter portion 16a and is located on the -Z side of the small diameter portion 16a.

[0025] As shown in FIG. 6 , the second member 20 has a second main body 21, two second flanges 22, and two positioning protrusions 24. Some components included in the optical connection structure 1 have symmetrical shapes in the first orthogonal direction X. For this reason, reference numerals for some components are omitted in FIG. 6 and other figures. The second main body 21 is cylindrical and extends in the axial direction Z. In this embodiment, the second housing 220 has a substantially rectangular parallelepiped shape, and accordingly, the second main body 21 is also rectangular cylindrical. However, the shapes of the second main body 21 and the second housing 220 can be modified. A second insertion opening 25 is provided at the -Z side end of the second main body 21. The second insertion opening 25 opens toward the -Z side. When connecting the optical connectors 100 and 200 using the adapter 2, the second optical connector 200 is inserted into the adapter 2 through the second insertion opening 25.

[0026] As shown in Figure 6, each of the two second flange portions 22 has a second fixing hole 22a formed therein. Two positioning protrusions 24 protrude toward the +Z side from each of the two second flange portions 22. The positioning protrusions 24 are annular when viewed from the axial direction Z, and are formed along the opening edge of the second fixing hole 22a. These positioning protrusions 24 fit into the insides of the two large diameter portions 16b of the first member 10. This determines the relative positions of the first member 10 and the second member 20.

[0027] The first member 10 and the second member 20 are fixed to each other by fixing means. In the example of Fig. 6, the fixing means are screws B and nuts N. More specifically, two screws B are inserted into the first fixing hole 16 and the second fixing hole 22a, and nuts N are threaded onto the ends of each screw B. However, the fixing means are not limited to screws and nuts, and may be, for example, an adhesive or the like.

[0028] As shown in Figure 5, the two locking pieces 17 of the first member 10 are disposed inside the first main body 11. The two locking pieces 17 are disposed apart in the first orthogonal direction X. Each locking piece 17 has a locking portion 17a that protrudes toward the internal space of the first main body 11. Each locking piece 17 is elastically deformable in the first orthogonal direction X, starting from its base end (the end of the locking piece 17 on the -Z side). The locking pieces 17 and the locking portion 17a function to lock the first optical connector 100 to the adapter 2.

[0029] As shown in FIG. 6 , the first optical connector 100 includes a first ferrule 110 and a first housing 120, as well as a first intermediate member 130, a movable member 140, a first boot 150, a support member 160, a first biasing member 170, and two auxiliary biasing members 180. As shown in FIG. 2 , the first ferrule 110 includes a plurality of first fiber holes 112 and the two first positioning holes 113 described above. The plurality of first fiber holes 112 and the two first positioning holes 113 open to the first connecting end face 111. The two first positioning holes 113 are spaced apart in the first orthogonal direction X, sandwiching the plurality of first fiber holes 112 therebetween. A first optical fiber F1 is inserted through each of the first fiber holes 112. The size (external dimension) of the first connecting end face 111 in the second orthogonal direction Y is referred to as a first dimension L1.

[0030] As shown in Figure 7, the first connecting end face 111 is inclined with respect to the second orthogonal direction Y. More specifically, the first connecting end face 111 is inclined toward the +Z side as it approaches the +Y side. Similarly, the second connecting end face 211 of the second ferrule 210 is also inclined. The inclined connecting end faces 111, 211 are formed, for example, by polishing the end faces of the ferrules 110, 210. The abutting surface 13a of the adapter 2 is also inclined to align with the first connecting end face 111. However, the connecting end faces 111, 211 and the abutting surface 13a do not have to be inclined.

[0031] As shown in FIG. 6 , the first housing 120 has a storage portion 121 and a wide portion 122. The storage portion 121 is a rectangular cylindrical portion extending in the axial direction Z. A portion of the first ferrule 110, the first intermediate member 130, the first biasing member 170, and a portion of the support member 160 are housed inside the storage portion 121. The wide portion 122 is located on the +Z side of the storage portion 121. In the first orthogonal direction X, the dimension of the wide portion 122 is larger than that of the storage portion 121. More specifically, the wide portion 122 protrudes from the +Z side end of the storage portion 121 toward both sides in the first orthogonal direction X. The wide portion 122 supports the auxiliary biasing member 180 from the +Z side (the base end side of the first optical connector).

[0032] The first intermediate member 130 is in contact with the end of the first ferrule 110 on the +Z side. The first intermediate member 130 has the role of transmitting the biasing force of the first biasing member 170 to the first ferrule 110. The movable member 140 is a so-called push-pull member that is gripped by the user when attaching or detaching. The movable member 140 has a rectangular cylindrical shape extending in the axial direction Z and surrounds the first housing 120 from the outside. A spring seat 141 that protrudes inward is formed on the movable member 140. The movable member 140 is movable in the axial direction Z relative to the first housing 120. Two auxiliary biasing members 180 are arranged in the gap between the movable member 140 and the first housing 120.

[0033] The +Z side end of the auxiliary biasing member 180 contacts the wide portion 122 of the first housing 120, and the −Z side end of the auxiliary biasing member 180 contacts the spring seat 141 of the movable member 140. The auxiliary biasing member 180 is, for example, a coil spring and is compressed in the axial direction Z. Therefore, the movable member 140 receives a biasing force from the auxiliary biasing member 180 toward the −Z side. When no external force is acting on the movable member 140, the biasing force of the auxiliary biasing member 180 causes the −Z side end of the movable member 140 to enter between the first main body portion 11 and the locking piece 17 of the adapter 2. This restricts the locking piece 17 from elastically deforming outward. When the user moves the movable member 140 toward the +Z side against the biasing force, the movable member 140 disengages from the adapter 2, allowing the locking piece 17 to elastically deform outward in the first orthogonal direction X.

[0034] As shown in FIG. 6 , the first housing 120 has two protrusions 123 that protrude from the accommodation portion 121 toward the +X side and the −X side. The locking portions 17a of the locking pieces 17 are locked onto these two protrusions 123. This restricts the first housing 120 from moving toward the +Z side relative to the adapter 2. To remove the first optical connector 100 from the adapter 2, the first optical connector 100 is simply pulled toward the +Z side while the movable member 140 is moved toward the +Z side. The locking portions 17a come into contact with the inclined surfaces of the protrusions 123, causing the locking pieces 17 to elastically deform outward in the first orthogonal direction X. As a result, the locking portions 17a are released from the protrusions 123, and the first optical connector 100 is detached from the adapter 2.

[0035] As shown in FIG. 6 , the support member 160 has a first support surface 161 and two engagement protrusions 162. The first support surface 161 faces the -Z side and contacts the +Z side end of the first biasing member 170. The -Z side end of the first biasing member 170 contacts the first intermediate member 130. The first biasing member 170 is, for example, a coil spring, and is compressed between the support member 160 and the first intermediate member 130. Furthermore, two engagement holes 124 are formed in the accommodating portion 121 of the first housing 120. The engagement protrusions 162 of the support member 160 engage with these engagement holes 124.

[0036] As shown in FIG. 6 , the second optical connector 200 includes a second ferrule 210, a second housing 220, a second intermediate member 230, an elastic locking piece 240, and a second boot 250. As shown in FIG. 3 , the second ferrule 210 includes a plurality of second fiber holes 212 and two second positioning holes 213. The plurality of second fiber holes 212 and the two second positioning holes 213 open to a second connecting end face 211. The two second positioning holes 213 are spaced apart in the first orthogonal direction X, sandwiching the plurality of second fiber holes 212 therebetween. Positioning pins 260 are inserted through the second positioning holes 213. A second optical fiber F2 is inserted through each of the second fiber holes 212. The size (external dimension) of the second connecting end face 211 in the second orthogonal direction Y is referred to as a second dimension L2.

[0037] 6, the second housing 220 has a distal side member 220a and a proximal side member 220b. The second housing 220 is formed by combining these two members 220a, 220b. However, the second housing 220 may be a single member. A part of the second ferrule 210, the second intermediate member 230, and the second biasing member 270 are housed inside the second housing 220.

[0038] The second intermediate member 230 is in contact with the end of the second ferrule 210 on the -Z side. The second intermediate member 230 has the role of transmitting the biasing force of the second biasing member 270 to the second ferrule 210. The second intermediate member 230 also holds two positioning pins 260. For this reason, the second intermediate member 230 is also referred to as a pin clamp. The elastic locking piece 240 is disposed on the -X side of the second housing 220. The elastic locking piece 240 has a locking protrusion 241 that protrudes toward the -X side. The second main body 21 of the adapter 2 also has a locking hole 21a. The locking protrusion 241 is locked in this locking hole 21a, thereby restricting movement of the second optical connector 200 toward the -Z side relative to the adapter 2. Although details are omitted, when the second optical connector 200 is removed from the adapter 2, the elastic locking piece 240 is elastically deformed, causing the locking protrusion 241 to move to the +X side and release the locking from the locking hole 21a.

[0039] The base-end member 220b of the second housing 220 has a second support surface 221 facing the +Z side. The -Z side end of the second biasing member 270 contacts the second support surface 221. The +Z side end of the second biasing member 270 contacts the second intermediate member 230. The second biasing member 270 is, for example, a coil spring, and is compressed between the second support surface 221 and the second intermediate member 230.

[0040] With the above configuration, a biasing force toward the -Z side generated by the first biasing member 170 acts on the first ferrule 110. Furthermore, a biasing force toward the +Z side generated by the second biasing member 270 acts on the second ferrule 210. Here, in this embodiment, the first optical connector 100 and the second optical connector 200 are different types. The area of ​​the first connecting end face 111 is larger than the area of ​​the second connecting end face 211. Furthermore, the biasing force acting on the first ferrule 110 is larger than the biasing force acting on the second ferrule 210. As a specific example, the biasing force acting on the first ferrule 110 is in the range of 18 to 22 N, and the biasing force acting on the second ferrule 210 is in the range of 7 to 13 N.

[0041] If the abutting portion 13 were not present, the difference in biasing force would cause the connection end faces 111, 211 in the axial direction Z to move toward the -Z side from the state shown in Figure 7. In this case, there is a possibility that the second biasing member 270 would be excessively compressed and deformed, or that unexpected interference between parts would occur between the two optical connectors 100, 200. As a result, there is a possibility that a good connection between the optical fibers F1, F2 cannot be maintained.

[0042] 7, the present embodiment is configured such that the first ferrule 110 cannot be inserted through the connection opening 14, and the second ferrule 210 can be inserted through the connection opening 14. More specifically, the dimensions L1, L2, and L3 shown in FIGS. 2 to 4 satisfy the following conditional expression (1): L1>L3>L2 (1)

[0043] In other words, the connection opening 14 has a shape that restricts the insertion of the first ferrule 110 through the connection opening 14 (a shape that satisfies conditional formula (1)), making it impossible for the first ferrule 110 to be inserted through the connection opening 14. Therefore, as shown in FIG. 7 , the range of movement of the first ferrule 110 toward the −Z side is determined by the position of the abutting portion 13 in the axial direction Z. Furthermore, the second ferrule 210 passes through the connection opening 14 toward the +Z side, and the second connection end face 211 abuts against the first connection end face 111. The position of the second ferrule 210 is determined by the balance between the biasing force of the first biasing member 170 and the biasing force of the second biasing member 270. Because the biasing force of the second biasing member 270 is smaller than the biasing force of the first biasing member 170, excessive movement of the second ferrule 210 toward the +Z side is suppressed. As described above, the positions of both the first ferrule 110 and the second ferrule 210 in the axial direction Z can be appropriately determined.

[0044] As described above, the adapter 2 of this embodiment connects a first optical connector 100 including a first housing 120 that holds therein a first ferrule 110 having a first connecting end face 111, and a second optical connector 200 that includes a second housing 220 that holds therein a second ferrule 210 that has a second connecting end face 211 that has an area smaller than that of the first connecting end face 111. The adapter 2 has a first insertion opening 18 through which the first housing 120 can be inserted, a second insertion opening 25 through which the second housing 220 can be inserted and that opens in the direction opposite to the first insertion opening 18 (the -Z side), and a connection opening 14 that is disposed between the first insertion opening 18 and the second insertion opening 25 and through which the second ferrule 210 can be inserted, and the connection opening 14 has a shape that limits the insertion of the first ferrule 110. According to such an adapter 2 or optical connection structure 1, two types of optical connectors 100, 200 that have different biasing forces acting on the ferrules can be properly connected to each other.

[0045] The adapter 2 also includes a first member 10 having a first insertion opening 18 and a second member 20 having a second insertion opening 25, with the first member 10 and the second member 20 being fixed together. This configuration allows the first member 10 or the second member 20 to be replaced with another member depending on the type of connector being used. For example, consider a case where the type of second optical connector 200 is changed. If the first insertion opening 18 and the second insertion opening 25 were provided in a single member, it would be necessary to prepare multiple variations of the adapter, each with a common first insertion opening 18 shape but a different second insertion opening 25 shape. The number of variations required is equal to the number of connector combinations.

[0046] In contrast, with the adapter 2 of this embodiment, if the type of second optical connector 200 is changed, the first member 10 can be used as is, and the second member 20 can be changed to another member. In other words, by dividing the adapter 2 into two members 10 and 20, the number of required variations can be reduced. Therefore, the overall costs due to the manufacturing or management of parts can be reduced.

[0047] Furthermore, the first optical connector 100 has a first biasing member 170 that biases the first ferrule 110, and the second optical connector 200 has a second biasing member 270 that biases the second ferrule 210. When the first ferrule 110 and the second ferrule 210 are in contact with each other, the biasing force of the first biasing member 170 on the first ferrule 110 may be within a range of 18 to 22 N, and the biasing force of the second biasing member 270 on the second ferrule 210 may be within a range of 7 to 13 N. Thus, even if the biasing forces of the first optical connector 100 and the second optical connector 200 are different, this embodiment allows the connection end faces 111 and 211 to be positioned appropriately. Therefore, the connection state of the optical fibers F1 and F2 can be stabilized.

[0048] Furthermore, the first optical connector 100 has a protrusion 123, and the adapter 2 has an abutting portion 13 that abuts against the first connecting end face 111 adjacent to the connection opening 14, and a locking portion 17a that locks with the protrusion 123. In the axial direction Z in which the first optical connector 100 and the second optical connector 200 face each other, the distance between the abutting portion 13 and the locking portion 17a is set so that the biasing force of the first ferrule 110 by the first biasing member 170 is within a range of 18 to 22 N. In other words, the position and biasing force of the first ferrule 110 in the axial direction Z are determined primarily by the structures of the first optical connector 100 and the adapter 2. This configuration allows for more stable optical connection than in the conventional case in which the position and biasing force of the ferrule fluctuate greatly depending on the balance of the biasing forces of the two ferrules.

[0049] 7, the abutting portion 13 has an abutting surface 13a that abuts against the first connecting end face 111, and the abutting surface 13a is inclined with respect to a plane perpendicular to the axial direction Z (the X-Y plane) so as to match the inclination of the first connecting end face 111. With this configuration, even if the first connecting end face 111 is polished and inclined, it is possible to prevent the first connecting end face 111 and the abutting surface 13a from making one-sided contact.

[0050] Furthermore, the abutting portion 13 surrounds the connection opening 14 when viewed from the axial direction Z. With this configuration, the abutting portion 13 and the first connection end face 111 can be abutted against each other so as to follow the contour of the outer periphery of the first connection end face 111. Therefore, the posture of the first ferrule 110 can be stabilized when the first connection end face 111 is abutted against the abutting portion 13.

[0051] Second Embodiment Next, a second embodiment of the present invention will be described. The basic configuration is similar to that of the first embodiment. Therefore, the same components are denoted by the same reference numerals, and their description will be omitted. Only the differences will be described. In this embodiment, as shown in Figures 8 and 9, an adapter 2A includes an outer housing 3, a rectangular inner plate 30, and an elastic member 40. The outer housing 3 includes a first member (first outer housing member) 10A and a second member 20A (second outer housing member).

[0052] 9 and 10 , the first main body portion 11 has a recess 190 at its end on the −Z side. The recess 190 is shaped like a rectangle recessed in the +Z direction. Specifically, the recess 190 is shaped so that the entire +Z side end of the inner plate 30 can fit into it. When the inner plate 30 is placed in the recess 190, the inner plate 30 is disposed at a distance from the first main body portion 11.

[0053] As shown in FIG. 11 , the second flange portion 22 of the second member 20A is provided with a plate accommodating portion 29 that accommodates the inner plate 30. The plate accommodating portion 29 is rectangular and recessed in the −Z direction. Specifically, the plate accommodating portion 29 is shaped so that the entire −Z-side end of the inner plate 30 can fit within it. When the inner plate 30 is disposed within the plate accommodating portion 29, the inner plate 30 is spaced apart from the second main body portion 21. The second member 20A also has a rectangular elastic member accommodating portion 26. The elastic member accommodating portion 26 is provided between the second main body portion 21 and the second flange portion 22. The elastic member accommodating portion 26 has cylindrical second holes 27 that open in the +Z direction formed at each of its four corners. As shown in FIG. 9 , an elastic member 40 is accommodated within each second hole 27, and a second spring abutment surface 28 is provided against which the −Z-side end of the elastic member 40 abuts.

[0054] As shown in FIG. 8 , the inner plate 30 is disposed in a space S formed by the recess 190 of the first member 10A and the plate accommodating portion 29 of the second member 20A. The inner plate 30 is disposed so as to be independently movable within the space S. As shown in FIG. 12 , the inner plate 30 is provided with a connection opening 30A penetrating in the Z direction. As shown in FIG. 8 , the connection opening 30A has, from the +Z side, a large diameter portion 30a, a small diameter portion 30b, and a medium diameter portion 30c. The large diameter portion 30a has an inner diameter larger than that of the medium diameter portion 30c, and the medium diameter portion 30c has an inner diameter larger than that of the small diameter portion 30b. The connection opening 30A is used to bring the two ferrules 110, 210 into contact with each other.

[0055] The small diameter portion 30b is provided with a contact portion 31 against which the first connecting end face 111 of the first ferrule 110 abuts. The contact portion 31 protrudes toward the inside of the connecting opening 30A beyond the large diameter portion 30a and the medium diameter portion 30c. The contact portion 31 has a first contact surface 31a facing the +Z side and abutting against the first connecting end face 111. The first contact surface 31a abuts against the +Y and −Y direction ends of the first connecting end face 111. However, the abutment portion 31 may abut against the first connecting end face 111 along the outer periphery. Furthermore, as shown in FIG. 12 , the inner plate 30 is provided with first hole portions 32 at each of the four corners of the −Z side end face. Each of the four first hole portions 32 is provided with a first spring contact surface 32a against which the +Z side end of the elastic member 40 abuts. The material of the inner plate 30 is not particularly limited, but examples thereof include resin and metal (for example, SUS material).

[0056] As shown in FIG. 14 , the +Z side end of the elastic member 40 contacts the first spring abutment surface 32a of the inner plate 30, and the −Z side end of the elastic member 40 contacts the second spring abutment surface 28 of the second member 20A. The elastic member 40 is, for example, a coil spring, and is compressed in the axial direction Z. As a result, the inner plate 30 receives a biasing force toward the +Z side, and the first connecting end surface 111 abutting the first abutment surface 31a of the inner plate 30 is biased toward the +Z side. In this embodiment, as shown in FIG. 13 , elastic members 40 are provided at the four corners of the inner plate 30. The biasing force of one elastic member 40 is 2 N. As a result, the biasing force acting on the inner plate 30 by the four elastic members 40 is 8 N.

[0057] Next, the positional relationship between the inner plate 30 and the second member 20A will be described. The inner plate 30 is positioned so as not to come into contact with the second member 20A. More specifically, as shown in FIG. 14 , if the dimension from the portion of the locking protrusion 241 that contacts the locking hole 21a (the base portion of the locking protrusion 241) to the tip surface 220c of the second housing 220 is defined as P1, and the dimension from the rear end of the locking hole 21a on the -Z side of the adapter 2A to the opposing surface 31b of the inner plate 30 opposite the first abutment surface 31a (the surface of the inner plate 30 that faces 220c of the second housing 220) is defined as P2, then the following conditional expression (2) is satisfied: P2>P1 (2)

[0058] By satisfying the above conditional expression (2), the inner plate 30 is positioned so as not to come into contact with the second member 20A, thereby preventing the second housing 220 from excessively biasing the inner plate 30 in the +Z-axis direction.

[0059] In this embodiment, as in the first embodiment, a biasing force toward the -Z side generated by the first biasing member 170 acts on the first ferrule 110. Furthermore, a biasing force toward the +Z side generated by the second biasing member 270 acts on the second ferrule 210. The first optical connector 100 and the second optical connector 200 are different types. The area of ​​the first connecting end face 111 is larger than the area of ​​the second connecting end face 211. Furthermore, the biasing force acting on the first ferrule 110 is larger than the biasing force acting on the second ferrule 210.

[0060] As a specific example, the biasing force applied to the first ferrule 110 by the first biasing member 170 is 18 N toward the −Z side, and the biasing force applied to the second ferrule 210 by the second biasing member 270 is 10 N toward the +Z side. In this embodiment, the elastic member 40 further biases the first ferrule 110 toward the +Z side via the inner plate 30 with a total biasing force of 8 N. That is, the first ferrule 110 is subjected to a biasing force of 8 N in addition to the 10 N toward the +Z side, so that a total biasing force of 18 N acts toward the +Z side. Therefore, the biasing force toward the +Z side and the biasing force toward the −Z side at the abutting surface between the second connecting end face 211 and the first connecting end face 111 are balanced, so that the positions of both the first ferrule 110 and the second ferrule 210 in the axial direction Z can be appropriate.

[0061] Furthermore, when the second housing 220 is in contact with the inner plate 30, the inner plate 30 may be pushed toward the +Z side from its designed position. However, in this embodiment, the above conditional expression (2) is satisfied, and therefore it is possible to prevent the first ferrule 110 from moving toward the +Z side more than necessary.

[0062] Although the outer housing is configured to include the first member 10A and the second member 20A, the first member 10A and the second member 20A may be integrated. Also, in this embodiment, four elastic members 40 are provided, but the number is not limited thereto, and two elastic members may be arranged diagonally, or the outer housing may be configured with one frame-shaped elastic member.

[0063] The technical scope of the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention.

[0064] For example, the structures of the optical connectors 100 and 200 described above are merely examples, and the disclosure of the above embodiments can be suitably used for two types of optical connectors with different ferrule biasing forces.

[0065] In addition, it is possible to replace the components in the above-described embodiments with well-known components as appropriate, and the above-described embodiments and variations may be combined as appropriate, without departing from the spirit of the present invention.

[0066] DESCRIPTION OF SYMBOLS 1...optical connection structure 2...adapter 3...outer housing 10...first member 13...abutment portion 14...connection opening 17a...locking portion 18...first insertion opening 20...second member 25...second insertion opening 100...first optical connector 110...first ferrule 111...first connection end surface 120...first housing 30...inner plate 31a...first abutment surface 31b...opposing surface 40...elastic member 123...projection 170...first biasing member 200...second optical connector 210...second ferrule 211...second connection end surface 220...second housing 241...locking projection 270...second biasing member Z...axial direction

Claims

1. An adapter for connecting a first optical connector including a first housing that holds a first ferrule having a first connecting end face therein, and a second optical connector including a second housing that holds a second ferrule having a second connecting end face that has an area smaller than that of the first connecting end face, a first insertion opening through which the first housing can be inserted; a second insertion opening through which the second housing can be inserted and which opens in a direction opposite to the first insertion opening; a connection opening, which is disposed between the first insertion opening and the second insertion opening and through which the second ferrule can be inserted, The connection opening has a shape that limits insertion of the first ferrule.

2. a first member having the first insertion opening; a second member having the second insertion opening, The adapter of claim 1 , wherein the first member and the second member are fixed.

3. an outer housing including the first insertion opening and the second insertion opening; an inner plate accommodated in the outer housing and having the connection opening; an elastic member that biases the inner plate toward the first connection end surface, the inner plate has a first abutment surface against which the first ferrule abuts; The adapter of claim 1 , wherein the resilient member is compressed between the outer housing and the inner plate.

4. The second optical connector is provided with a locking protrusion, The outer housing is provided with a locking hole into which the locking projection is locked, 4. The adapter according to claim 3, wherein the dimension from the rear end of the locking hole to the opposing surface of the inner plate opposite the first abutment surface is greater than the dimension from the portion of the locking projection that contacts the locking hole to the tip surface of the second housing.

5. The outer housing includes a first outer housing member and a second outer housing member.

5. The adapter according to claim 3, wherein the inner plate is disposed within a space defined by the first outer housing member and the second outer housing member.

6. The adapter according to claim 1 or 2; the first optical connector; an optical connection structure comprising: the second optical connector;

7. the first optical connector has a first biasing member that biases the first ferrule, the second optical connector has a second biasing member that biases the second ferrule, 7. The optical connection structure according to claim 6, wherein, when the first ferrule and the second ferrule are in contact with each other, the biasing force of the first ferrule exerted by the first biasing member is within a range of 18 to 22 N, and the biasing force of the second ferrule exerted by the second biasing member is within a range of 7 to 13 N.

8. the first optical connector has a protrusion, the adapter has a contact portion adjacent to the connection opening and contacting the first connection end surface, and a locking portion locked to the protrusion, The optical connection structure described in claim 7, wherein in the axial direction in which the first optical connector and the second optical connector face each other, the distance between the abutment portion and the locking portion is set so that the biasing force of the first ferrule by the first biasing member is within the range of 18 to 22 N.