Optical connector

Abstract

An optical connector (1) includes: a ferrule (10) including a connection end surface (10a) in which a plurality of fiber holes (11) are formed side by side in a Z-axis direction (first direction); an urging member (60) for urging the ferrule (10) in an X-axis direction (second direction) in which the connection end surface (10a) faces; a pin clamp (50) for transmitting the urging force of the urging member (60) to the ferrule (10); and a housing (20) for accommodating a portion of the ferrule (10), the urging member (60), and the pin clamp (50). The urging member (60) is an elliptical coil spring with the long axis extending in the Z-axis direction, and the dimension of at least the major axis changes as the urging member increasing approaches the ferrule (10) in the X-axis direction.

Description

Optical Connector

[0001] This application claims priority to Japanese Patent Application No. 2024-098103, filed on June 18, 2024, the contents of which are incorporated herein by reference.

[0002] Patent Document 1 below discloses an optical connector that accommodates multiple optical fibers. Such an optical connector generally includes a ferrule having multiple fiber holes into which multiple optical fibers are inserted in the longitudinal direction, a spring that biases the ferrule toward a connection target such as another connector, and a housing that accommodates part of the ferrule and the spring.

[0003] US Patent Application Publication No. 2023 / 0161116

[0004] Incidentally, the multi-fiber optical connector described above uses an elliptical coil spring. An elliptical coil spring has the advantage of requiring less space than a circular coil spring. However, an elliptical coil spring is prone to buckling if not compressed perpendicularly along its axial direction. If an elliptical coil spring buckles, the designed load will not be applied to the connecting end face of the ferrule, which may result in a mechanical connection failure of the optical fiber.

[0005] The present invention has been made in view of the above problems, and has as its object to ensure stable mechanical connection of optical fibers in a multi-fiber optical connector.

[0006] An optical connector according to a first aspect of the present invention comprises a ferrule having a connection end face in which a plurality of fiber holes are formed in a row in a first direction, a biasing member that biases the ferrule in a second direction in which the connection end face faces, an intermediate member that transmits the biasing force of the biasing member to the ferrule, and a housing that accommodates a portion of the ferrule, the biasing member, and the intermediate member, wherein the biasing member is an elliptical coil spring whose major axis extends in the first direction and at least the major diameter dimension changes as it moves toward the ferrule in the second direction.

[0007] In a second aspect of the present invention, in the optical connector of the first aspect, the biasing member may have a major diameter that decreases toward the ferrule in the second direction.

[0008] A third aspect of the present invention is the optical connector according to the first or second aspect, wherein the center position of the biasing member does not change in a direction perpendicular to the second direction.

[0009] A fourth aspect of the present invention is an optical connector according to the first or second aspect, which is provided with a latch provided on one side of the housing in the first direction, and the center position of the biasing member may change in the first direction relative to the latch.

[0010] A fifth aspect of the present invention is an optical connector according to any one of the first, second, and fourth aspects, which is provided with a latch provided on one side of the housing in the first direction, and the dimension of the biasing member on the side closer to the latch in the first direction may become smaller as it moves toward the ferrule in the second direction.

[0011] A sixth aspect of the present invention is the optical connector according to the fifth aspect, wherein the biasing member may have a constant dimension on a side farther from the latch in the first direction.

[0012] According to the above aspect of the present invention, stable mechanical connection of optical fibers can be ensured in a multi-fiber optical connector.

[0013] Fig. 1 is a perspective view of an optical connector according to a first embodiment. Fig. 2 is a front view of the optical connector according to the first embodiment. Fig. 3 is a cross-sectional view of the optical connector according to the first embodiment. Fig. 4 is an exploded perspective view of the optical connector according to the first embodiment. Fig. 5 is a cross-sectional view of the optical connector according to a second embodiment. Fig. 6 is an exploded perspective view of the optical connector according to the second embodiment. Fig. 7 is a side view showing the connected state of an optical connector according to a comparative example.

[0014] The optical connector of this embodiment will be described below with reference to the drawings.

[0015] (First embodiment) Fig. 1 is a perspective view of an optical connector 1 according to a first embodiment. Fig. 2 is a front view of the optical connector 1 according to the first embodiment. As shown in Fig. 1, the optical connector 1 includes a ferrule 10, a housing 20, and a boot 30. The ferrule 10 has a plurality of fiber holes 11 formed therein, which are aligned in a row. The plurality of fiber holes 11 may be aligned in two or more rows.

[0016] The ferrule 10 has a connection end face 10a in which a plurality of fiber holes 11 are formed. The connection end face 10a has fiber holes 11 and positioning holes 12 open. An optical fiber F is arranged in each of the plurality of fiber holes 11. Note that some of the fiber holes 11 may not have an optical fiber F arranged in them. In other words, the number of optical fibers F may be less than the number of fiber holes 11. The optical fibers F are exposed to the outside at the connection end face 10a. The optical connector 1 can be connected to another optical connector by abutting the connection end face of the other optical connector to be connected to the connection end face 10a.

[0017] In the following description, an XYZ Cartesian coordinate system is set, and the positional relationship of each component is sometimes described with reference to this XYZ Cartesian coordinate system. As shown in the figure, the X-axis direction is set to the connection direction of the optical connector 1 (the direction in which the connection end face 10a faces, the direction in which the fiber holes 11 extend, and the longitudinal direction of the optical connector 1). In the X-axis direction, the side of the connection end face 10a (+X side) may be referred to as the front side, and the opposite side (-X side) may be referred to as the rear side.

[0018] The Y-axis direction is set to the width direction of the optical connector 1 (short direction of the optical connector 1). In the Y-axis direction, one side (+Y side) may be referred to as the right side, and the other side (-Y side) may be referred to as the left side. The Z-axis direction is set to the height direction of the optical connector 1 (the direction in which the multiple fiber holes 11 are lined up in a row). In the Z-axis direction, one side (+Z side) may be referred to as the upper side, and the other side (-Z side) may be referred to as the lower side.

[0019] As shown in Fig. 2, the ferrule 10 has two positioning holes 12. The positioning holes 12 open to the connection end face 10a and penetrate the ferrule 10 in the X-axis direction. The two positioning holes 12 are spaced apart in the Z-axis direction. The two positioning holes 12 are arranged so as to sandwich a plurality of fiber holes 11 between them in the Z-axis direction. The optical connector 1 of this embodiment is a female side (female connector), and the relative positions of the optical connector 1 and the other optical connector are determined by inserting a positioning pin of another connector (male connector) into the positioning hole 12.

[0020] Recesses 13 and 14 are formed on a pair of side surfaces of the ferrule 10 facing the Y-axis direction. The recesses 13 and 14 are recessed inward in the Y-axis direction from the pair of side surfaces of the ferrule 10 facing the Y-axis direction. The housing 20 is formed with protrusions 21a and 21b that engage with the recesses 13 and 14. This determines the position of the ferrule 10 relative to the housing 20. The protrusions 21a and 21b function as so-called centering keys.

[0021] As shown in FIG. 1 , the housing 20 has a front housing 21, a rear housing 22, and a cover 23. The front housing 21 is attached to the front side (+X side) of the rear housing 22. The cover 23 is attached to the upper side (+Z side) of the rear housing 22. The housing 20 may be a single member. That is, the front housing 21, the rear housing 22, and the cover 23 may be integrally formed as a single member. A fitting hole 21c is formed on the side surface of the front housing 21 in the Y-axis direction. A fitting protrusion 22b that fits into the fitting hole 21c is formed on the side surface of the rear housing 22 in the Y-axis direction.

[0022] The cover 23 has an opening 23a in which the latch 40 is disposed. The latch 40 is provided on only one side (+Z side) of the housing 20. The latch 40 engages with an adapter (not shown) when connecting an optical fiber. In other words, the optical connector 1 has an asymmetrical engagement shape. The latch 40 is provided on only one side (+Z side) of the housing 20 in order to reduce the size of the optical connector 1, etc.

[0023] Fig. 3 is a cross-sectional view of the optical connector 1 according to the first embodiment. Fig. 4 is an exploded perspective view of the optical connector 1 according to the first embodiment. As shown in Fig. 3, the latch 40 includes a fixed portion 41, a bent portion 42, and a curved portion 43. The latch 40 is disposed between the rear housing 22 and the cover 23.

[0024] The fixed portion 41 is sandwiched and fixed between the rear housing 22 and the cover 23. The bent portion 42 is connected to the rear side of the fixed portion 41 and is bent in a V-shape. The top (upper end) of the bent portion 42 protrudes to the outside through the opening 23a of the cover 23 and is capable of engaging with an adapter (not shown). The curved portion 43 is connected to the rear side of the bent portion 42 and is curved in a hook shape from rear to front (and from bottom to top). The tip of the curved portion 43 contacts the inner wall of the cover 23. When the curved portion 43 is pressed so that the bent portion 42 is flattened, it has a spring force that pushes back the bent portion 42 so that it bends to its original state.

[0025] The housing 20 accommodates a pin clamp 50 (intermediate member) and a biasing member 60. The tip end (the end on the +X side) of the ferrule 10 protrudes from the front end opening of the housing 20. An optical fiber F (not shown) is inserted through the fiber hole 11 of the ferrule 10, extends in the X-axis direction, passes through an insertion hole 51 a of the pin clamp 50, the inside of the biasing member 60, and an insertion hole 22 a of the rear housing 22, and is inserted into the inside of the boot 30.

[0026] Pin clamp 50 is disposed on the rear side (-X side) of ferrule 10. In other words, pin clamp 50 is disposed on the opposite side of ferrule 10 from connection end face 10a. Pin clamp 50 contacts the rear side of ferrule 10 and holds ferrule 10. Pin clamp 50 has the role of transmitting the biasing force of biasing member 60 to ferrule 10.

[0027] The pin clamp 50 has a main body 51 and two positioning pins 52. The main body 51 has an insertion hole 51a through which an optical fiber F (not shown) passes in the X-axis direction. The two positioning pins 52 protrude forward (toward the +X direction) from the main body 51. The relative positions of the ferrule 10 and the pin clamp 50 are determined by inserting the two positioning pins 52 into the positioning holes 12 of the ferrule 10.

[0028] Because the optical connector 1 of this embodiment is female, the positioning pin 52 does not protrude from the ferrule 10 toward the tip. If the optical connector 1 is male (male connector), the positioning pin 52 may protrude from the ferrule 10 toward the tip. On the rear side (-X side) of the pin clamp 50, a seat surface 60B that receives the front end of the urging member 60 is formed on the rear peripheral edge of the insertion hole 51a. On the inside of the rear housing 22, a seat surface 60A that receives the rear end of the urging member 60 is formed on the front peripheral edge of the insertion hole 22a.

[0029] As shown in Fig. 4, the biasing member 60 is an elliptical coil spring. The major axis of the elliptical biasing member 60 extends in the Z-axis direction. The minor axis of the elliptical biasing member 60 extends in the Y-axis direction. As shown in Fig. 3, the major axis dimension (dimension in the Z-axis direction) of the biasing member 60 changes as it moves toward the ferrule 10 in the X-axis direction. Specifically, the major axis dimension of the biasing member 60 decreases as it moves toward the ferrule 10 in the X-axis direction.

[0030] The major axis of the urging member 60 has a dimension D1 at the rear end on the seat surface 60A side. The major axis of the urging member 60 has a dimension D2 at the front end on the seat surface 60B side. D1 and D2 have a relationship of D1 > D2. In other words, the urging member 60 has a tapered shape in which the major axis dimension decreases from D1 to D2 toward the ferrule 10 in the X-axis direction. Note that, although only the major axis dimension of the urging member 60 in this embodiment changes, the minor axis dimension (dimension in the Y-axis direction) may also change.

[0031] As the biasing member 60 moves toward the ferrule 10 in the X-axis direction, the dimension of the biasing member 60 on the side closer to the latch 40 in the Z-axis direction (+Z side) decreases, and the dimension of the biasing member 60 on the side farther from the latch 40 in the Z-axis direction (-Z side) decreases by the same proportion. In other words, the center position of the biasing member 60 (the center position of the biasing member 60 in a plane perpendicular to the X-axis direction) is on the central axis O1 of the ferrule 10, and does not change in the directions perpendicular to the X-axis direction (the Y-axis direction and the Z-axis direction) over the entire biasing member 60 in the X-axis direction.

[0032] 3, the biasing member 60 is an elliptical coil spring whose major axis extends in the Z-axis direction, and at least the major axis dimension changes as it moves toward the ferrule 10 in the X-axis direction. The tapered biasing member 60 is compressed in sequence from the larger diameter side (-X side) to the smaller diameter side (+X side), thereby preventing buckling of the elliptical coil spring. This allows the biasing member 60 to be compressed without buckling up to the position where the design load is generated, enabling stable mechanical connection of the optical fiber F.

[0033] As described above, the optical connector 1 according to this embodiment includes a ferrule 10 having a connecting end face 10a on which a plurality of fiber holes 11 are formed aligned in the Z-axis direction (first direction), a biasing member 60 that biases the ferrule 10 in the X-axis direction (second direction) toward which the connecting end face 10a faces, a pin clamp 50 (intermediate member) that transmits the biasing force of the biasing member 60 to the ferrule 10, and a housing 20 that accommodates a portion of the ferrule 10, the biasing member 60, and the pin clamp 50. The biasing member 60 is an elliptical coil spring whose major axis extends in the Z-axis direction, and at least the dimension of its major diameter changes as it moves toward the ferrule 10 in the X-axis direction. With this configuration, a stable mechanical connection of the optical fibers F can be ensured in the multi-core optical connector 1.

[0034] In this embodiment, the major axis of the biasing member 60 decreases in the X-axis direction toward the ferrule 10. With this configuration, the biasing member 60 is compressed in sequence from the larger diameter side (-X side) toward the smaller diameter side (+X side), thereby suppressing swinging (tilting) of the ferrule 10.

[0035] In addition, in this embodiment, the center position of the urging member 60 does not change in the direction perpendicular to the X-axis direction across the entire urging member 60 in the X-axis direction. This configuration makes it easier to compress the urging member 60 vertically along the central axis O1.

[0036] Second Embodiment Next, a second embodiment of the present invention will be described. In the following description, the same or equivalent components as those in the above-described embodiment will be denoted by the same reference numerals, and the description thereof will be simplified or omitted.

[0037] Fig. 5 is a cross-sectional view of the optical connector 1 according to the second embodiment. Fig. 6 is an exploded perspective view of the optical connector 1 according to the second embodiment. As shown in these figures, in the second embodiment, the center position of the urging member 60 (the center position of the urging member 60 in a plane perpendicular to the X-axis direction) is shifted in the Z-axis direction with respect to the latch 40.

[0038] Specifically, the biasing member 60 has a tapered shape in which the major axis dimension decreases from D3 to D4 as it approaches the ferrule 10 in the X-axis direction, and also has an eccentric elliptical shape whose center position gradually moves away from the latch 40 toward the −Z side. In other words, the central axis O2 of the biasing member 60 intersects with the central axis O1 of the ferrule 10 at a predetermined angle.

[0039] The dimension of the biasing member 60 on the side closer to the latch 40 in the Z-axis direction (+Z side) decreases as it approaches the ferrule 10 in the X-axis direction. The side of the biasing member 60 closer to the latch 40 (+Z side) means the side above the central axis O1 of the ferrule 10. The +Z side of the biasing member 60 has a dimension A1 at the rear end on the seating surface 60A side. The +Z side of the biasing member 60 has a dimension A2 at the front end on the seating surface 60B side. A1 and A2 have a relationship of A1 > A2.

[0040] Furthermore, the dimension of the biasing member 60 on the side (-Z side) farther from the latch 40 in the Z-axis direction is constant. The side (-Z side) of the biasing member 60 farther from the latch 40 means the side below the central axis O1 of the ferrule 10. The -Z side of the biasing member 60 has a dimension A1 at the rear end on the seating surface 60A side. The -Z side of the biasing member 60 also has a dimension A1 at the front end on the seating surface 60B side. In other words, the dimension A1 does not change on the -Z side of the biasing member 60.

[0041] Fig. 7 is a side view showing the connection state of an optical connector 100 according to a comparative example. The optical connector 100 shown in Fig. 7 includes a ferrule 110 having a connection end face 110a and a housing 120 that accommodates a portion of the ferrule 110. Inside the housing 120, there are accommodated a spring (a normal oval coil spring) (not shown) that biases the ferrule 110 in the X-axis direction, and a pin clamp (not shown) that transmits the biasing force of the spring to the ferrule 110.

[0042] One side (+Z side) of the housing 120 is provided with a latch 140 that engages with the adapter 200 when connecting optical fibers. In the optical connector 100 with such an asymmetrical engagement shape, the pressing force between the ferrules 110 when connecting optical fibers is received by the latch 140 located on one side. As a result, the optical connector 100 rotates around the latch 140 as a fulcrum, and the pressing force F1 on the side farther from the latch 140 becomes weaker than the pressing force F2 on the side closer to the latch 140. This poses a problem in that mechanical connection failures are likely to occur in optical fibers located farther from the latch 140.

[0043] 5, the center position of the biasing member 60 is shifted in the Z-axis direction relative to the latch 40. Specifically, the dimension of the biasing member 60 on the side closer to the latch 40 in the Z-axis direction (+Z side) decreases as the biasing member 60 moves toward the ferrule 10 in the X-axis direction, making it possible to relatively increase the biasing force on the side farther from the latch 40 (-Z side). This achieves a balance between the biasing force of the biasing member 60 on the side closer to the latch 40 (+Z side) and the biasing force on the side farther from the latch 40 (-Z side), thereby eliminating mechanical connection problems with the optical fiber F arranged farther from the latch 40.

[0044] While preferred embodiments of the present invention have been described and illustrated, it should be understood that these are illustrative of the present invention and should not be considered as limiting. Additions, omissions, substitutions, and other modifications can be made without departing from the scope of the present invention. Accordingly, the present invention should not be deemed limited by the foregoing description, but rather by the scope of the claims.

[0045] For example, in the above embodiment, a configuration has been described in which the major axis dimension of the urging member 60 decreases as it moves toward the ferrule 10 in the X axis direction, but the major axis dimension of the urging member 60 may increase as it moves toward the ferrule 10 in the X axis direction. In this case, the urging member 60 is compressed sequentially from the larger diameter side (+X side) toward the smaller diameter side (−X side), and therefore, the same effects as those of the above embodiment can be achieved.

[0046] 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.

[0047] 1...optical connector, 10...ferrule, 10a...connection end face, 11...fiber hole, 12...positioning hole, 13...recess, 14...recess, 20...housing, 21...front housing, 21a...protrusion, 21b...protrusion, 21c...fitting hole, 22...rear housing, 22a...insertion hole, 22b...fitting protrusion, 23...cover, 23a...opening, 30...boot, 40...latch, 41...fixing portion 42...Bending portion, 43...Curved portion, 50...Pin clamp, 51...Main body, 51a...Insertion hole, 52...Positioning pin, 60...Using member, 60A...Seat, 60B...Seat, 100...Optical connector, 110...Ferrule, 110a...Connection end face, 120...Housing, 140...Latch, 200...Adapter, F...Optical fiber, F1...Pressing force, F2...Pressing force, O1...Central axis, O2...Central axis

Claims

1. An optical connector comprising: a ferrule having a connecting end face on which a plurality of fiber holes are formed aligned in a first direction; a biasing member that biases the ferrule in a second direction in which the connecting end face faces; an intermediate member that transmits the biasing force of the biasing member to the ferrule; and a housing that contains a portion of the ferrule, the biasing member, and the intermediate member, wherein the biasing member is an elliptical coil spring whose major axis extends in the first direction and at least the dimension of its major axis changes as it moves toward the ferrule in the second direction.

2. The optical connector according to claim 1, wherein the major axis of the biasing member decreases in the second direction toward the ferrule.

3. An optical connector according to claim 1 or 2, wherein the central position of the biasing member does not change in a direction perpendicular to the second direction.

4. An optical connector according to claim 1 or 2, further comprising a latch provided on one side of the housing in the first direction, and the center position of the biasing member varies in the first direction relative to the latch.

5. An optical connector according to any one of claims 1, 2 and 4, further comprising a latch provided on one side of the housing in the first direction, and wherein the dimension of the biasing member on the side closer to the latch in the first direction decreases as the biasing member moves toward the ferrule in the second direction.

6. The optical connector according to claim 5, wherein the biasing member has a constant dimension on the side farther from the latch in the first direction.

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