Optical housings, optical harnesses, and in-vehicle networks

Abstract

To enable inexpensive bending restrictions at the base of optical cables without compromising the difficulty of cable routing. [Solution] An apparatus according to one aspect of the present disclosure is an optical housing in which a bending restricting portion for the root portion of an optical cable is integrated, wherein the bending restricting portion has a guide hole in which the root portion of the optical cable is housed, and the inner surface forming the guide hole includes a guide surface whose inner diameter increases from the inside to the outside of the optical housing, and the outer opening end of the guide surface terminates on the wall surface of the optical housing.

Description

[Technical Field]

[0001] The present disclosure relates to an optical housing, an optical harness, and an in-vehicle network. [Background Art]

[0002] An optical cable may be bent during routing. If the bending radius of the optical cable becomes excessively small, transmission degradation may occur or the internal optical fiber may be damaged. In particular, the root portion of the optical cable accommodated in the optical connector serves as a base point for bending behavior and is often bent with a small bending radius. In view of such a problem, Patent Documents 1 to 3 propose techniques related to bending restriction of the root portion of an optical cable.

[0003] Specifically, Patent Document 1 describes a bending boot that is easily attachable to and detachable from an optical cable and holds the optical cable such that the bending shape thereof is not smaller than the minimum bending radius. Patent Document 2 describes a connector terminal structure for an optical cable, in which bending of the optical cable is restricted by a protection member that covers the outer periphery of an extension protection region which is at least a part of the optical cable.

[0004] Further, Patent Document 3 describes an optical connector in which the minimum value of the bending radius of an optical fiber is restricted by a bending guide portion integrally formed on a housing main body portion into which an end portion of the optical fiber is inserted. [Prior Art Documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Unexamined Patent Application Publication No. 2009-282177 [Patent Document 2] Japanese Unexamined Patent Application Publication No. 2014-98823 [Patent Document 3] Japanese Unexamined Patent Application Publication No. 2003-149504 [Summary of the Invention] [Problems that the invention aims to solve]

[0006] Patent documents 1 and 2 require additional parts such as boots and protective members, which presents the problem of increased effort and cost for bending control. Patent Document 3 achieves bending restriction without increasing the number of parts by integrating the bending guide section. However, since the bending guide section protrudes from the housing body, there is a problem that the bending guide section gets in the way and makes cable routing difficult.

[0007] In light of the aforementioned conventional problems, this disclosure aims to enable inexpensive bending restrictions at the base of optical cables without compromising the difficulty of cable routing. [Means for solving the problem]

[0008] An apparatus according to one aspect of the present disclosure is an optical housing in which a bending restricting portion for the root portion of an optical cable is integrated, the bending restricting portion having a guide hole for housing the root portion of the optical cable, the inner surface forming the guide hole includes a guide surface whose inner diameter increases from the inside to the outside of the optical housing, and the outer opening end of the guide surface terminates on the wall surface of the optical housing. [Effects of the Invention]

[0009] According to this disclosure, bending restrictions at the base of optical cables can be implemented inexpensively without compromising the difficulty of cable routing. [Brief explanation of the drawing]

[0010] [Figure 1] Figure 1 is a perspective view showing an example of the external configuration of an optical harness. [Figure 2] Figure 2 is a cross-sectional view showing an example of the cross-sectional structure of an optical cable. [Figure 3] Figure 3 is an exploded perspective view of the longitudinal end of the optical housing. [Figure 4]Figure 4 is a plan view of the optical housing body showing an example of the guide hole shape. [Figure 5] Figure 5 is a connection diagram showing an example of an in-vehicle network using an optical harness. [Modes for carrying out the invention]

[0011] <Summary of the embodiments of this disclosure> The embodiments of this disclosure are outlined below.

[0012] (1) An apparatus according to one aspect of this embodiment is an optical housing in which a bending restricting portion for the root portion of an optical cable is integrated, wherein the bending restricting portion has a guide hole in which the root portion of the optical cable is housed, and the inner surface forming the guide hole includes a guide surface whose inner diameter increases from the inside to the outside of the optical housing, and the outer opening end of the guide surface terminates on the wall surface of the optical housing.

[0013] According to the optical housing of this embodiment, since the bending restriction portion is integrated into the optical housing, bending of the base portion of the optical cable can be restricted without providing additional parts such as the aforementioned boots or protective members. Therefore, bending restriction of the base portion of the optical cable can be performed inexpensively. Furthermore, since the outer opening end of the guide surface, which forms the guide hole at the base of the cable, terminates at the wall of the optical housing, the bending restriction portion does not get in the way during cable routing. Therefore, bending restrictions can be implemented at the base of the optical cable without compromising the ease of cable routing.

[0014] (2) In the optical housing described in (1) above, the shape of the guide surface may be an arc surface with a predetermined radius of curvature. This approach simplifies the manufacturing of molds and other components for forming the guide surface compared to using curved surfaces other than circular arcs.

[0015] (3) In the optical housing described in (2) above, the radius of curvature may be the minimum radius of curvature specified for the optical cable. According to this configuration, the bending of the optical cable is restricted by the guide surface such that the limit of bending the optical cable is the minimum radius of curvature.

[0016] (4) In the optical housing according to (2) and (3) above, the forming angle of the arc-shaped surface may be an angle value in a range of 15 degrees or more and 45 degrees or less. According to this configuration, the dimension of the bending restricting portion in the width direction can be made more compact compared to a case where the forming angle of the arc-shaped surface is 45 degrees or more.

[0017] (5) An apparatus according to another aspect of the present embodiment is an optical harness comprising: an optical cable; and the optical housing according to any one of (1) to (4) above, which is a housing that covers a terminal end portion of the optical cable. According to the optical harness of the present embodiment, since it includes the optical housing according to any one of (1) to (4) above, it exhibits the same operational effects as the optical housing according to any one of (1) to (4) above.

[0018] (6) In the optical harness according to (5) above, there are a plurality of said optical cables, and said optical housing may be a member that accommodates a connecting body that connects a plurality of optical fibers respectively leading to said plurality of optical cables in a branched configuration. By using such an optical harness, a tree-structured network in which a plurality of optical communication communication nodes are connected in a one-to-many manner can be easily constructed.

[0019] (7) An apparatus according to another aspect of the present embodiment is an in-vehicle network comprising: the optical harness according to (6) above; and a plurality of in-vehicle devices respectively connected via optical connectors provided at ends of said plurality of optical cables. According to the in-vehicle network of the present embodiment, a tree-structured network configuration in which a plurality of in-vehicle devices are connected in a one-to-many manner can be adopted.

[0020] <Details of Embodiments of the Present Invention> The embodiments of the present invention will be described in detail below with reference to the drawings. At least some of the embodiments described below may be combined in any way.

[0021] [Definition of Terms] In order to describe the details of the embodiments of this disclosure, we will first define the key terms.

[0022] "Optical cable": A cable with a structure that houses optical fibers within a sheath with a circular cross-section. Also called a "fiber optic cable." It can house one or more optical fibers. "Optical harness": An assembly of optical transmission components that includes at least one optical cable and an optical housing or optical connector attached to at least one end of the optical cable. Also called an "optical cable assembly".

[0023] "Optical housing": This is a housing that covers the termination portion of an optical cable. The housing may be made of plastic or metal, or a composite of plastic and metal. Since it is a housing that covers a connector that connects the ends of multiple optical fibers, it can connect two or more optical cables. If there are three or more, a splitter for connecting three or more optical fibers in a branched configuration is housed in the optical cover member. "Optical connector": This refers to a housing that has a mating portion for other optical connectors. In this embodiment, the optical connector is considered to be a type of optical housing.

[0024] "Extension direction": This refers to the direction along the center line of the optical cable when the optical cable of an optical harness is extended in a generally straight line. "First direction": This refers to the direction in which the optical cable extends. In this embodiment, the direction of the X-axis (X direction) in the illustrated three-dimensional coordinate system is defined as the first direction (extension direction).

[0025] "Second direction": This refers to any direction orthogonal to the first direction among the in-plane directions of the virtual plane S (see Figure 1) whose normal coincides with the first direction (extension direction). In this embodiment, the direction of the Y axis (Y direction) in the illustrated three-dimensional coordinate system is defined as the second direction. "Third direction": This refers to the in-plane direction of the virtual plane S (see Figure 1) where the normal coincides with the first direction (extension direction), and which is perpendicular to the first and second directions. In this embodiment, the direction of the Z axis (Z direction) in the illustrated three-dimensional coordinate system is defined as the third direction.

[0026] [Example of optical harness configuration] Figure 1 is a perspective view showing an example of the external configuration of the optical harness 100. Figure 2 is a cross-sectional view showing an example of the cross-sectional structure of the optical cable 10. Figure 3 is an exploded perspective view of the longitudinal end of the optical housing 30.

[0027] As shown in Figure 1, the optical harness 100 of this embodiment comprises a plurality of optical cables 10 (three in the illustrated example) and a connector 20 that connects each optical fiber 12 that leads to each of the plurality of optical cables 10. Furthermore, the optical harness 100 of this embodiment has an optical housing 30 that covers the above-mentioned connector 20 from the surroundings.

[0028] [Example of optical cable configuration] As the optical cable 10, an optical cable developed for automotive use, such as the one described in Japanese Patent Publication No. 2013-213988, can be used. As shown in Figure 2, for example, such an optical cable 10 comprises a sheath 11 with a circular cross-section, an optical fiber 12 housed inside the sheath 11, and a plurality of tension members 13 surrounding the optical fiber 12 inside the sheath 11.

[0029] The optical fiber 12 is made of, for example, glass. In the example in Figure 2, the optical fiber 12 has two cores, but it may also have one core. The tension member 13 functions as a tensile strength member, such as a Kevlar fiber ("Kevlar" is a registered trademark). The tension member 13 is filled into the sheath 11 at a density that does not hinder the movement of the optical fiber 12 in the cross-sectional direction. The sheath 11 is a flexible cylindrical member made of a polypropylene-based resin material that is resistant to degradation.

[0030] As shown in Figure 4, an engaging member 14, for example, as described in Japanese Patent Publication No. 5254499, is fixed to the end of the sheath 11 of the optical cable 10. The engaging member 14 is a cylindrical body having a small-diameter portion 15 and a large-diameter portion 16 integrally. The small-diameter portion 15 is crimped to the outer circumferential surface of the end of the sheath 11. The large-diameter portion 16, together with an inner ring (not shown) housed in this portion, is the part that fixes the tension fiber 13 so that it cannot move in the stretching direction (X direction).

[0031] [Example of optical housing configuration] As shown in Figures 1 and 3, the optical housing 30 is composed of a hollow casing with the longest dimension in the X direction, and includes an optical housing body 40 and a lid member 50 as its components. Both the optical housing body 40 and the lid member 50 are made of, for example, thermoplastic engineering plastic. The joining of these members 40 and 50 is achieved, for example, by engaging the claw member 53 of the lid member 50 with the engaging projection 46 of the optical housing body 40.

[0032] As shown in Figure 3, the optical housing 30 has a bending restriction portion 60 at the base of the optical cable 10 housed inside the optical housing 30. The bending restricting portion 60 is a wall structure integrated with the longitudinal end (X-direction end in the illustrated example) of the optical housing body 40, and includes a first restricting portion 61 integrated on the optical housing body 40 side and a second restricting portion 62 integrated on the lid member 50 side.

[0033] The first restricting section 61 and the second restricting section 62 have a symmetrical, split shape in the height direction (Z direction). Therefore, when the opening of the optical housing body 40 is closed with the cover member 50, the first restricting section 61 and the second restricting section 62 abut against each other in the Z direction to form a single bending restricting section 60. The bending restriction section 60 has at least one guide hole 63, which is a through hole in the X direction, and the base portion of the optical cable 10 is housed in the guide hole 63.

[0034] The bending restricting sections 60 are positioned at both ends of the optical housing 30 in the X direction. One guide hole 63 is formed in the bending restricting section 60 located at one end in the X direction, and a pair of guide holes 63, 63 are formed in the bending restricting section 60 located at the other end in the X direction, separated in the Y direction.

[0035] [Examples of guide hole shapes for bending restriction sections] Figure 4 is a plan view of the optical housing body 40 showing an example of the shape of the guide hole 63. As shown in Figure 4, the inner surface forming the guide hole 63 includes a retaining surface 64 with a constant inner diameter and a guide surface 65 whose inner diameter increases as it moves from the inside (positive X-direction side) to the outside (negative X-direction side) of the optical housing body 40.

[0036] The inner diameter of the retaining surface 64 is approximately equal to the outer diameter of the optical cable 10. Therefore, the retaining surface 64 has the function of holding the orientation of the sheath 11 of the optical cable 10 in the X direction. The X-direction end face of the bending restricting portion 60 constitutes the wall surface 40A of the optical housing body 40 (which is also the wall surface of the optical housing 30), and the outer opening end 65A of the guide surface 65 terminates at the wall surface 40A. Therefore, the bending restricting portion 60 in this embodiment does not protrude outward in the X direction relative to the optical housing 30.

[0037] The shape of the guide surface 65 can be formed as an arcuate surface with a predetermined radius of curvature R. The radius of curvature R may be the minimum radius of curvature specified for the optical cable 10 (e.g., 7.5 mm). When adopting a circular arc with a predetermined radius of curvature R as the shape of the guide surface 65, the arc formation angle θ is often set to 90 degrees. However, setting θ=90 degrees presents a problem in that the widthwise dimension (Y-direction dimension) of the bending restricting portion 60 increases, leading to an increase in size.

[0038] Therefore, verification using an actual optical cable 10 (for example, the cross-sectional shape shown in Figure 2) revealed that the angular range in which the actual part can follow a circular arc surface with R=7.5mm is approximately 45 degrees. Accordingly, by setting the angular value of the forming angle θ to, for example, a range of 30 degrees or more and 45 degrees or less, the widthwise dimension of the bending restricting portion 60 can be made more compact. Furthermore, CAE (Computer-Aided Engineering) analysis confirmed that when the formation angle θ is set to 30 degrees, the curvature of the optical fiber 12 inside the sheath 11 does not fall below the allowable value even when the optical cable 10 is bent until the routing distance D from the wall surface 40A is 8 mm.

[0039] [Example of in-vehicle network configuration] Figure 5 is a connection diagram showing an example of an in-vehicle network using the optical harness 100. As shown in Figure 5, an optical connector 70A is connected to the end of one optical cable 10A of the optical harness 100, and the optical connector 70A is connected to the POB connector of the ECU (Electronic Control Unit) 80A.

[0040] Similarly, optical connectors 70B are connected to the ends of the two optical cables 10B of the optical harness 100, and each optical connector 70B is connected to a POB connector on the ECU 80B. In this way, by connecting one ECU 80A and two ECUs 80B, 80B using the branched optical harness 100 of this embodiment, an in-vehicle network with a one-to-many tree structure for the connection of multiple in-vehicle devices 80A, 80B, 80B can be easily constructed.

[0041] [Other variations] The embodiments described above are illustrative and not restrictive in all respects. The scope of this disclosure is defined by the claims and is intended to include all modifications in the sense and scope equivalent to the claims.

[0042] In the above-described embodiment, an example was given in which the bending restriction portion 60 is provided on the optical housing 30 having the connector 20, but the bending restriction portion 60 may also be provided on other optical housings such as optical connectors (for example, optical connectors 70A and 70B in Figure 5). [Explanation of Symbols]

[0043] 10 Optical Cables 10A fiber optic cable 10B Fiber Optic Cable 11 Sheath 12 Optical Fibers 13 Tension Fibers 14 Engaging Member 15 Small diameter section 16 Large diameter section 20 connectors 30 Optical Housing 40 Optical Housing Body 40A Wall 46 Engagement protrusion 50 Lid member 53 Claw member 60 Bending restriction section 61 First Regulatory Section 62 Second Regulatory Section 63 Guide holes 64 Holding surface 65 Guide surface 65A Outer open end 70A Optical Connector 70B Optical Connector 80A,80B,80B In-vehicle unit (ECU) 100 Optical Harness

Claims

1. An optical housing in which the bending restriction section at the base of the optical cable is integrated, The aforementioned bending restricting portion is The optical cable has a guide hole into which the base portion is housed, The inner surface that forms the guide hole is An optical housing comprising a guide surface whose inner diameter increases from the inside to the outside of the optical housing, wherein the outer opening end of the guide surface terminates on the wall surface of the optical housing.

2. The shape of the aforementioned guide surface is, The optical housing according to claim 1, wherein the surface is an arc of a circular curvature with a predetermined radius of curvature.

3. The radius of curvature is, The optical housing according to claim 2, wherein the optical cable has the minimum radius of curvature specified in the optical cable.

4. The angle at which the arc surface is formed is, The optical housing according to claim 2, wherein the angle value is in the range of 15 degrees or more and 45 degrees or less.

5. Optical cable and An optical harness comprising an optical housing according to any one of claims 1 to 4, which is a housing that covers the termination portion of the optical cable.

6. The aforementioned optical cables are multiple, The optical housing is The optical harness according to claim 5, which is a member that houses a connector for connecting multiple optical fibers, each leading to the multiple optical cables, in a branched configuration.

7. The optical harness according to claim 6, An in-vehicle network comprising: a plurality of in-vehicle devices, each connected via optical connectors provided at the ends of the plurality of optical cables.

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