Webbing for a motor vehicle seat belt system

Abstract

Webbing for a seat belt system (10) of a motor vehicle, comprising a woven webbing body (121) which has longitudinally extending warp threads and transversely extending weft threads, and at least one optical fiber (32, 34) which is woven into the webbing body (121), wherein several optical fibers (32, 34) are bundled together in a warp thread section (321, 341) to form a warp thread and individual optical fibers (32, 34) forming the warp thread with the warp thread section (321, 341) are woven into the webbing body (121) with a weft thread section (322, 342) in the direction of the weft threads of the webbing body (121).

Description

[0001] The invention relates to a webbing for a safety belt system of a motor vehicle, comprising a woven webbing body which has longitudinally running warp threads and transversely running weft threads, and at least one light guide which is woven into the webbing body.

[0002] Such seat belt systems are generally known from the prior art and constitute a simple and effective safety device for an occupant in a collision accident of a motor vehicle, whereby the seat belt system is intended to prevent a secondary collision of an occupant with a vehicle interior component, such as a steering wheel, an instrument panel or the like, and to prevent the occupant from being ejected from a motor vehicle.

[0003] To ensure that seat belts are always worn and to prevent them from being forgotten, acoustic and / or visual warning systems exist that emit a signal if an occupant is not wearing a seat belt. Detection of unfastened seat belts can be achieved, for example, using information from an interior camera. The camera monitors the area of ​​the vehicle's seating area and tracks the position of the seat belt. If a person is detected in the seat and the seat belt's position does not follow a predefined pattern, the warning system emits a signal. To ensure the seat belt can be detected even in darkness, it is illuminated. This is achieved by woven fiber optic cables into the seat belt.

[0004] The illuminated seatbelt ensures reliable visibility even in darkness. Furthermore, the illuminated seatbelt can be located more quickly by the occupant in the dark if they wish to fasten their arm. Such a seatbelt system is disclosed, for example, in WO 2019 / 144 750 A1.

[0005] A disadvantage of seat belts with integrated fiber optics is that the brightness decreases steadily with increasing distance from the light source to which the fiber optic is coupled, because light rays are continuously emitted along the length of the belt. This loss of brightness is particularly noticeable with long fiber optic cables. This creates the risk that the seat belt cannot be reliably detected by the interior camera in the dark, or only with considerable effort. Furthermore, the loss of brightness along the length of the fiber optic cable and its path along the seat belt detracts from the seat belt's appearance.

[0006] The object of the invention is to provide a webbing for a safety belt system of a motor vehicle in which homogeneous illumination through the light guide can be ensured in a simple and cost-effective manner.

[0007] The problem is solved by the features of claim 1.

[0008] According to the invention, several optical fibers bundled in a warp thread section form a warp thread, wherein individual optical fibers forming the warp thread with the warp thread section are woven into the weft body with a weft thread section in the direction of the weft threads of the weft body.

[0009] Each optical fiber thus comprises a warp thread section and a weft thread section adjoining the warp thread section. In the warp thread section of the optical fiber, total internal reflection of the light rays coupled into the optical fiber should occur as far as possible, so that the optical fiber in this section should function solely as a light guide. In the weft thread section of the optical fiber, the light rays coupled in and transmitted through the warp thread section by reflection should be coupled out of the optical fiber, thereby providing an illuminated webbing. To couple the light rays out of the optical fiber, a coupling structure is preferably formed on the weft thread section, which is designed in particular by having notches, a grinding structure, or a grooved structure on its surface. Due to the coupling structure, the optical fiber, i.e.,In the weft thread section, no total internal reflection of the coupled light rays takes place, whereby the light rays are coupled out.

[0010] Preferably, the weft thread sections of different light guides are woven into the webbing body at longitudinal intervals, thereby providing homogeneous illumination of the webbing in the longitudinal direction.

[0011] By designing the webbing in this way, the loss of brightness can be reduced in a simple manner by making the section of the light guide that couples out the light rays, i.e., the weft thread section, so short that the loss of brightness is negligible. This allows for homogeneous illumination of the base tape.

[0012] Preferably, each optical fiber has a single weft section, such that the weft section has a free end. This allows the light-emitting section of the optical fiber to be relatively short, with the weft sections of all optical fibers being of the same length. This ensures homogeneous illumination of the webbing. Alternatively, the weft section is loop-shaped, such that the optical fiber has a first warp section, a loop-shaped weft section, and a second warp section, with the weft section located between the two warp sections. In this case, the light-emitting weft section of the optical fiber is first unthreaded from the optical fiber bundle formed by the warp sections of the optical fibers and then rethreaded.This prevents the light guide bundle forming the warp thread from thinning longitudinally, as the light guides are returned. Preferably, the same light guides can have several loop-like weft thread sections at different locations. To compensate for any visible loss of brightness, the light extraction structure formed on the loop-like weft thread sections consists of several notches spaced apart longitudinally along the light guides, the geometry of which changes with distance from a light source. In this way, depending on the distance to the light source, more or less light can be extracted from the light guide by adjusting the design of the notches, thus compensating for the loss of brightness.

[0013] Preferably, several optical fibers, forming a first warp thread with the warp thread section, are arranged at a first edge region of the webbing, and several optical fibers, forming a second warp thread, are arranged at a second edge region. In this process, light beams are guided at both edge regions of the webbing via the warp thread sections of the optical fibers to predefined, distinct locations, i.e., the connection points of the weft thread sections, by total internal reflection within the optical fibers. Subsequently, starting from the edge regions, the light is coupled out of the optical fiber via the weft thread sections due to the coupling structure. This ensures a reliable, homogeneous light distribution or illumination of the webbing both transversely and longitudinally.In particular, the weft thread sections of the optical fiber forming the first warp thread and the weft thread sections of the optical fiber forming the second warp thread are arranged alternately in the longitudinal direction, thereby providing a particularly homogeneous light distribution on the webbing. When the optical fibers are designed with a loop-like weft thread section, the warp thread sections of the optical fiber forming the first warp thread are preferably arranged within the loop-like weft thread sections of the optical fiber forming the second warp thread.

[0014] Preferably, the optical fibers bundled in the warp thread section are coupled at one end to a single light source. This means that only one light source is required for all optical fibers. In a particularly preferred embodiment, the warp thread sections of the optical fibers forming the first warp thread and the warp thread sections of the optical fibers forming the second warp thread are bundled at one end and coupled to a single light source. This means that only one light source is required even if an optical fiber bundle is provided at both edge regions of the webbing.

[0015] An embodiment of the invention is explained in more detail with reference to the drawings. Fig. Figure 1 schematically shows a safety belt system in front view, Fig. Figure 2a shows a section of a first embodiment of a webbing of the safety belt system made of Fig. 1 in perspective view, Fig. Figure 2b shows the first version of the webbing of the safety belt system. Fig. 1 in detailed view, Fig. Figure 3a shows a section of a second version of a webbing of the safety belt system made of Fig. 1 in perspective view, Fig. Figure 3b shows the second version of the webbing of the safety belt system. Fig. 1 in detailed view, and Fig. Figure 4 shows a section of a light guide of the webbing of the seat belt system. Fig. 1 in perspective view.

[0016] In Fig. Figure 1 shows a seat belt system 10 for a motor vehicle, wherein the seat belt system 10 is used to fasten a person P.

[0017] The safety belt system 10 comprises a webbing 12, a belt retractor 14, an end fitting 16, a deflector 18, a tongue 20 and a belt buckle 22.

[0018] The webbing 12 is attached to the vehicle at one end via the end fitting 16 and at a second end opposite the first end via the belt retractor 14. The webbing 12 can be coupled to the belt buckle 22 via the movably attached plug tongue 20.

[0019] The webbing 12 comprises a webbing body 121, which has longitudinally running warp threads and transversely running weft threads. The webbing 12 also includes a lighting device 30, which extends from a first end of the webbing 12 in the area of ​​the end fitting 16 along the entire length of the webbing 12 to a second end of the webbing 12 opposite the first end in the area of ​​the belt retractor 14. In the area of ​​attachment to the vehicle, the lighting device 30 is coupled to a light source via a connecting element 35.

[0020] The lighting device 30 is in the Fig. 2a, Fig. 2b, Fig. 3a, Fig. 3b and Fig. Figure 4 shows the lighting device 30 comprising several light guide bundles 31, 33, each with several light guides 32, 34, wherein the light guides 32, 34 are each divided into a warp thread section 321, 341 and a weft thread section 322, 342. A first light guide bundle 31 with a first group of light guides 32 is arranged at a first edge region of the webbing body 121. A second light guide bundle 33 with a second group of light guides 34 is arranged at a second edge region of the webbing body 121. The warp thread sections 321, 341 of the light guides 32, 34 form a warp thread of the woven webbing body 121. The weft thread sections 322, 342 connect to the warp thread sections 322, 342 and run transversely to the warp thread section 322, 342, i.e. in the direction of the weft threads of the webbing body 121.The weft thread sections 322, 342 are integrated into the webbing body 121 in such a way that the weft thread sections 322, 342 are woven into the webbing body 121, as shown in . Fig. 2a and in Fig. Figure 3a shows that the weft thread sections 322 of the optical fiber 32 and the weft thread sections 342 of the optical fiber 34 are arranged alternately in the longitudinal direction of the webbing 12. The optical fiber bundles 31, 33 are connected to a single connecting element 35 and thus to a single light source.

[0021] According to Fig. 2a The optical fibers 32, 34 have only a single weft thread section 322, 342, which has a free end. According to Fig. 3a the weft thread sections 322, 342 are loop-shaped, wherein the warp thread sections 321 of the optical fiber 32 forming the first warp thread are arranged within the loop-shaped weft thread sections 342 of the optical fiber 34 forming the second warp thread and vice versa.

[0022] Each optical fiber 32, 34 thus comprises a warp thread section 321, 341 and a weft thread section 322, 342 adjoining the warp thread section 321, 341. Total internal reflection of the light rays coupled into the optical fiber 32, 34 takes place in the warp thread section 321, 341. In the weft thread section 322, 342 of the optical fiber 32, 34, the light rays coupled at the connecting element 35 and transmitted through the warp thread sections 321, 341 by total internal reflection are coupled out of the optical fiber 32, 34. To couple the light rays out of the optical fiber 32, 34, an output coupling structure 50 with several notches is formed on the weft thread section 322, 342. Such an output coupling structure 50 is partially in Fig. Figure 4 shows that, due to the coupling structure 50, total internal reflection of the coupled light rays does not occur in the weft thread sections 322 and 342, thus coupling the light rays out. In the loop-like design of the weft thread sections 322 and 342 according to... Fig. 3a varies the geometry of the notches with the distance to the light source. In this way, depending on the distance to the light source, more or less light can be coupled out of the light guide by adjusting the design of the notches, thus compensating for the loss of brightness.

Claims

[1] Webbing for a seat belt system (10) of a motor vehicle, comprising a woven webbing body (121) having longitudinally extending warp threads and transversely extending weft threads, and at least one optical fiber (32, 34) woven into the webbing body (121), characterized by , that several optical fibers (32, 34) are bundled together in a warp thread section (321, 341) to form a warp thread and individual optical fibers (32, 34) forming the warp thread with the warp thread section (321, 341) are woven into the weft body (121) with a weft thread section (322, 342) in the direction of the weft threads of the weft body (121). [2] Webbing according to claim 1, characterized by , that the weft thread sections (322, 342) of different light guides (32, 34) are woven into the webbing body (121) at intervals between each other in the longitudinal direction of the webbing body (121). [3] Webbing according to claim 1 or 2, characterized by, that each optical fiber (32, 34) has a single weft section (322, 342) such that the weft section (322, 342) has a free end. [4] Webbing according to claim 1 or 2, characterized by , that the weft section (322, 342) is loop-shaped, such that the optical fiber (32, 34) has a first warp section (361), a loop-shaped weft section (322, 342) and a second warp section (362), wherein the weft section (322, 342) is located between the two warp sections (361, 362). [5] Webbing according to any one of the preceding claims, characterized by , that several optical fibers (32) forming a first warp thread with the warp thread section are arranged at a first edge region of the webbing body (121) and several optical fibers (34) forming a second warp thread are arranged at a second edge region. [6] Webbing according to claim 5, characterized by, that the weft thread sections (322) of the optical fibers (32) forming the first warp thread and the weft thread sections (342) of the optical fibers (34) forming the second warp thread are arranged alternately in the longitudinal direction. [7] Webbing according to claims 5 and 6, characterized by , that the warp thread sections (321) of the optical fibers (32) forming the first warp thread are arranged within the loop-like weft thread sections (342) of the optical fibers (34) forming the second warp thread. [8] Webbing according to any one of the preceding claims, characterized by , that the optical fibers (32, 34) bundled in the warp thread section (321, 341) are coupled at one end to a single light source. [9] Webbing according to claims 5 and 8, characterized by, that the warp thread sections (321) of the optical conductor (32) forming the first warp thread and the warp thread sections (341) of the optical conductor (34) forming the second warp thread are bundled at one end and coupled to a single light source. [10] Webbing according to any one of the preceding claims, characterized by , that a light output coupling structure (50) is formed on the weft thread section (322, 342) of the optical fiber (32, 34). [11] Webbing according to claim 10, characterized by , that the light output structure (50) is formed by several notches spaced apart from each other in the longitudinal direction of the light guides (32, 34), the geometry of the notches changing with distance to a light source.

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