Airbag module with light-emitting surface

Abstract

Airbag module with a case (10), a cover (20) comprising a roof (25) with an outer surface, wherein the cover (20) has a first part (30) comprising a first section (31) of the roof (25), an airbag cushion (80) located within a receiving space enclosed by the housing (10) and / or the first part (30) of the cover (20), an inflation device for inflating the airbag cushion (80), at least one light-emitting element (66) arranged outside the recording space, wherein the light-emitting element (66) has an active state in which it emits light, and a lighting arrangement with a light-emitting surface (53a) forming a section of the outer surface of the roof (25), such that the light-emitting surface (53a) emits light to the outside of the module when the light-emitting element (66) is in its active state, characterized in that the cover (20) further comprises: a second part (40) located outside the reception area and comprising a second section (42) of the roof (25) covering the light-emitting element (66), wherein the second section (42) of the roof (25) is at least partially separated from the first section (31) of the roof (25), a third part (50) which is different from the first part (30), wherein the third part (50) comprises a third section (53) of the roof (25) which fills the gap between the first section (31) of the roof (25) and the second section (42) of the roof (25) and has the light-emitting surface (53a).

Description

[0001] The invention relates to an airbag module according to the preamble of claim 1 and a method for manufacturing it according to claim 13.

[0002] The invention primarily relates to so-called driver airbag modules, which are designed and intended for mounting on the steering wheel of a vehicle. For this reason, reference is mainly made to such a driver airbag module; however, it should be mentioned that the invention can also be applied to other types of airbag modules, in particular to so-called passenger airbag modules.

[0003] A driver airbag module typically consists of a housing and a cover, such that the housing and cover enclose a receiving space for an airbag cushion. Furthermore, an inflation device is provided, usually mounted on a bottom wall of the housing. The cover naturally includes a roof spanning the housing, with this roof having a visible outer surface. A section of this roof forms a door that can be opened by the deploying airbag cushion. This door is connected to a surrounding section of the roof by at least one predetermined breaking point and at least one hinge.

[0004] In most cases, the cover still has a side panel that is connected to the housing, often by a snap-fit ​​connection. The cover is usually an injection-molded plastic part.

[0005] To improve the optical appearance of the cover (namely its roof), it is known to provide a lighting arrangement which has a light-emitting surface which forms a section of the outer surface of the roof of the cover.

[0006] For example, EP 1 973 767 A1 discloses the use of a light-emitting element (which could also be called a "light-generating element") outside the airbag's receiving space and directing the light from this element via a light guide to a central section of the roof that has a light-emitting surface. The problem with this method is that the light guide is usually located in the airbag's deployment path.

[0007] JP 2008 - 238 879 A1 shows something similar.

[0008] DE 697 30 642 T2 proposes, among other things, to provide light-emitting elements and light guides in the roof of a driver airbag module.

[0009] US patent 5,203,226 A describes a steering wheel for a bus which features an illuminated element. This steering wheel does not include an airbag module.

[0010] The generic patent US 6 848 706 (also published as US 2002 / 0 153 712 A1) also shows an airbag module whose roof has a light-emitting surface. Here, the lighting arrangement is located completely outside the airbag's receiving area, so that this lighting arrangement does not impede the airbag's deployment.

[0011] From DE 10 2017 223 719 A1 a steering wheel is known in which a light guide designed to emit light extends section by section around the steering wheel hub in which the driver airbag is received.

[0012] Based on this state of the art, it is an object of the invention to further improve a generic airbag module.

[0013] This problem is solved by an airbag module having the features of claim 1. A method for manufacturing such an airbag module is specified in claim 13.

[0014] The method for creating the receiving space through the housing and cover while inserting the airbag cushion into this receiving space is often relatively crude and requires specialized machinery. It has been found that ensuring the lighting assembly elements are not damaged during this process can be difficult. According to the invention, the airbag module is therefore constructed such that it comprises a first subassembly including the airbag cushion packed into the receiving space and the elements enclosing this receiving space, and this subassembly can be manufactured before any lighting assembly element is mounted to it.

[0015] To achieve this, the cover need not consist of a single part (as is common in the prior art), but of at least a first part, a second part, and a third part. The first part can be connected to the housing so that this first part and the housing enclose the airbag receiving space. This first part can comprise a first roof section having at least one door that can be opened by the deploying airbag. The second part can be located outside the receiving space and comprises a second roof section that covers the light-emitting element. This second roof section can be spaced at least partially apart from the first roof section. Furthermore, the cover can comprise a third part that is different from the first part.This third part may include a third section of the roof that fills the gap between the first section of the roof and the second section of the roof, and may include the light-emitting surface.

[0016] Since the second part of the cover typically needs to have different properties than the first and second parts (in particular, it must be at least partially transparent or translucent), it is often preferred that the first, second, and third parts of the cover are separate components. Alternatively, the third part can be integrally formed with the second part.

[0017] In an optically and mechanically preferred geometry, the third section of the roof can be ring-shaped and surround the first section, and the second section can also be ring-shaped and surround the third section. In this geometry, the third roof section can additionally form a seal between the first and second roof sections.

[0018] To facilitate assembly, it may be preferable for the third roof section to be snap-fitted to at least one of the two roof sections, preferably to the first and second roof sections.

[0019] As mentioned previously, the third section of the roof can include the light-emitting surface. Therefore, this third section can preferably be, or include, a light diffuser. A preferred material for the light diffuser is silicone, particularly a silicone with a Shore hardness between 30 and 90 Shore A. This facilitates the installation process and ensures a tight seal.

[0020] Since the third part does not emit light, the lighting arrangement typically includes a light-receiving surface to receive light from the light-emitting element. Although it would be possible in principle to feed the light generated by the light-emitting element directly into the third part of the cover, for geometric reasons and to optimize light scattering homogeneity, it is often preferable for the lighting arrangement to still include a separate light-guiding element to direct the light from the light-emitting element to the third part of the cover, with this light-guiding element comprising the light-receiving surface. This light-guiding element can be made, for example, of silicone, polymethyl methacrylate (PMMA), or polycarbonate (PC).

[0021] As mentioned previously, the housing, the first part of the cover, and the airbag can be components of a first subassembly. This first subassembly can also include the inflation device. The second part of the cover, the third part of the cover, and the light-emitting element can be components of a second subassembly attached to the first subassembly. If a light guide element is used, it can also be part of the second subassembly.

[0022] In a preferred method for manufacturing an airbag module, the assembly of the first subassembly can be completed before the second subassembly, or parts of the second subassembly, are mounted to the first subassembly, thus preventing damage to a part of the second subassembly. Preferably, the entire second subassembly can be completed before it is mounted to the first subassembly.

[0023] The invention will now be described in more detail with reference to preferred embodiments and the figures. The figures show: Fig. 1 all elements of a first subassembly of the described embodiment of the airbag module, Fig. 2 all elements of a second sub-assembly of the described embodiment of the airbag module, Fig. 3 the fully assembled first sub-assembly and the fully assembled second sub-assembly in a state in which the second sub-assembly is not yet mounted to the first sub-assembly, Fig. 4 the fully assembled airbag module (the first sub-assembly made of Fig. 3 and the second sub-assembly made of Fig. 3, which is mounted on the first sub-assembly), Fig. 5 the detail D from Fig. 4, where the airbag cushion is not shown, and Fig. 6 A perspective view of the airbag module.

[0024] A key concept of the invention is that the airbag module comprises two subassemblies, one subassembly (the first subassembly) comprising all the elements required to form a "conventional" airbag module. The elements of this first subassembly are arranged in Fig. shown:

[0025] A housing 10 and a first part 30 of the cover define a receptacle for an airbag cushion 80, which can be inflated by a gas generator 70. As is known from the prior art, this gas generator 70 is attached to the bottom wall 11 of the housing 10. The space enclosed by the housing 10 and the first part 30 of the cover is also referred to as the receptacle for the airbag cushion.

[0026] The housing 10 is largely designed like a conventional housing, i.e., it consists of a housing side wall 14 and the aforementioned bottom wall 11. An opening 12 for the inflator is provided in the center of the bottom wall 11. Furthermore, several holes 13 for hooks of the first part of the cover are provided in a radially outer section of the bottom wall 11. In the embodiment shown, the gas generator 70 comprises a main body 72 and a mounting flange 74 for attaching the gas generator 70 to the bottom wall 11.

[0027] A fastening section 15 extends radially outwards from the upper end of the side wall 14. Instead of a single ring-shaped fastening section 15, several fastening sections 15 could also be provided.

[0028] The first part 30 of the cover, like an ordinary cover, comprises a side wall 34 and a roof section, namely the first section 31 of the roof. The first section 31 of the roof is essentially flush with the side wall 34.

[0029] As is generally known from the prior art, 34 fastening hooks 36 extend from the lower edge of the side wall.

[0030] Fig. Figure 1 shows all elements of a second subassembly of the airbag module. In the described embodiment, this second subassembly comprises the following elements: a second part 40 of the cover and a third part 50 of the cover are provided. In this embodiment, the second part 40 of the cover forms exclusively a second section 42 of the roof, and the third part 50 of the cover forms exclusively a third section 53 of the roof. For this reason, the terms "second part of the cover" and "second section of the roof" can be used interchangeably, and the terms "third part of the cover" and "third section of the roof" can also be used interchangeably.

[0031] The second part 40 of the cover is usually an injection-molded part made of a standard, opaque airbag module cover material, for example thermoplastic olefin (TPO) and / or thermoplastic elastomer (TPE), but another material may also be used, since this second part 40 of the cover is located outside the receiving space that receives the airbag cushion 80.

[0032] The third part 50 of the cover (also referred to as a diffuser) consists of a translucent, diffusing material that preferably exhibits a certain degree of elasticity. Based on current knowledge, the preferred material for this third part 50 is silicone.

[0033] Both the second part 40 and the third part 50 are ring-shaped, such that the second part 40 forms an outer ring and the third part 50 an inner ring. Connecting devices are provided so that the third part 50 can be attached to the second part 40, preferably functioning without adhesive or similar materials. In this embodiment, these connecting devices are a projection 43 on the second part 40 and a groove 54 in the third part 50. Alternatively, the second part 40 can be integrally formed with the third part 50, or vice versa.

[0034] The third part 50 also has fastening devices for attaching the third part 50 to the first part 30 of the cover.

[0035] When the airbag module is fully assembled, the upper surface of the third part 50 forms a light-emitting surface 53a of the roof of the cover of this airbag module. Since the third part 50 does not emit light, a lighting subassembly 60 is provided to supply the third part 50 with light. In the embodiment shown, this lighting subassembly 60 comprises three elements: - To generate the light, an electronic unit 65 is provided, comprising a ring-shaped printed circuit board (PCB) 64 and a plurality of light-emitting diodes (LEDs) 66 as light-emitting elements (which could also be referred to as light-generating elements). The LEDs 66 are mechanically and electrically connected to the printed circuit board 64. - To direct the light generated by the LEDs 66 to the third part 50 of the cover (the diffuser), a light guiding element 68 is provided which has a tubular section with a light receiving surface 68a. - Finally, a fastening element 62 with a flange section 62a and a pipe section 62b serves to fasten the electronic unit 65 and the light guide element 68 to the fastening section 15 of the housing side wall.

[0036] Fig. The first sub-assembly, consisting of the in Fig. The elements shown are present, and the second sub-assembly consists of the elements shown. Fig. The elements shown are present. It should be noted that these two subassemblies can be assembled completely independently of each other, so that the first subassembly (consisting of the first part 30 of the cover, the housing 10, the airbag cushion 80 and the gas generator 70) is completely free of any light-generating, light-conducting or light-emitting parts. The first subassembly is assembled like a conventional airbag module, so no further explanation is necessary.

[0037] For the second subassembly: The third part 50 is attached to the upper ends of the tube section 62b of the mounting element 62 and the light guide element 68, such that the third part 50 is in contact with or in close proximity to the upper end of the light guide element 68. This allows the light entering the light guide element 68 at the light-receiving surface 68a to be directed to the third part 50, so that it can be emitted from the light-emitting surface 53a. The LEDs 66 are located near the light-receiving surface 68a of the light guide element 68. The second part 40 of the cover is attached at its upper end to the third part 50 of the cover as described above and at its lower end to the flange section 62a of the mounting element 68.The light-emitting diodes 66 are completely enclosed by the second part 40 of the cover and the flange section 62a, so that the light generated by the light-emitting diodes 66 can only leave this enclosure via the light emission surface 53a of the third part 50.

[0038] Fig. The figure shows the fully assembled airbag module after the second sub-assembly has been attached to the first sub-assembly. In this final assembly step, the flange section 62a is attached to the mounting section 15, and the third part 50 of the cover is snapped onto the first part 30 of the cover.

[0039] Fig. detail D shows Fig. , however without the airbag cushion 80. It can be seen that the light emission surface 53a, the outer surface of the roof 25a and the second section of the roof 42 are flush and form a single continuous outer visible surface.

[0040] Fig.Figure 1 shows the airbag module again, and in particular its roof 25. The ring-shaped structure of the third part 50 and the second part 40 can be seen. In particular, it can be seen that the third part of the cover (third section 53 of the roof) fills and seals the gap between the first section 31 of the roof and the second section 42 of the roof.

[0041] The light-emitting elements (the LEDs 66) are hidden under the second section 42 of the roof, but when they are in their active, light-emitting state, at least some of this light is emitted from the light-emitting surface 53a. Reference symbol list 10 cases 11 Floor wall 12 Opening for the inflator 13 Opening for cover hooks 14 Case side panel 15 Mounting section of the housing side panel 20 Cover 25 roof 25a Exterior surface of the roof 30 first part of the cover 31 first part of the roof 31a External surface of the first part of the roof 34 Side wall of the first part of the cover 36 fastening hooks 40 second part of the cover 42 Second part of the roof 42a External surface of the second part of the roof 43 Nose 50 third part of the cover (diffuser) 53 third part of the roof 53a External surface of the third part of the roof / light exit surface 54 Nut 60 illuminating sub-assemblies 62 Fastening element 62a Flange section 62b Pipe section 63 screw 64 circuit boards 65 electronic unit 66 LEDs (light-emitting elements) 68 Light guiding element 68a Light receiving area 70 Gas generator 72 Main body of the gas generator 74 Mounting flange 80 airbag cushions

Claims

[1] Airbag module with a case (10), a cover (20) comprising a roof (25) with an outer surface, wherein the cover (20) has a first part (30) comprising a first section (31) of the roof (25), an airbag cushion (80) located within a receiving space enclosed by the housing (10) and / or the first part (30) of the cover (20), an inflation device for inflating the airbag cushion (80), at least one light-emitting element (66) arranged outside the recording space, wherein the light-emitting element (66) has an active state in which it emits light, and a lighting arrangement with a light-emitting surface (53a) forming a section of the outer surface of the roof (25), such that the light-emitting surface (53a) emits light to the outside of the module when the light-emitting element (66) is in its active state, characterized by , that the cover (20) further exhibits: a second part (40) located outside the reception area and comprising a second section (42) of the roof (25) covering the light-emitting element (66), wherein the second section (42) of the roof (25) is at least partially separated from the first section (31) of the roof (25), a third part (50) which is different from the first part (30), wherein the third part (50) comprises a third section (53) of the roof (25) which fills the gap between the first section (31) of the roof (25) and the second section (42) of the roof (25) and has the light-emitting surface (53a). [2] Airbag module according to claim 1, characterized by , that the first part (30) of the cover (20), the second part (40) of the cover (20) and the third part (50) of the cover (20) are different parts. [3] Airbag module according to one of claims 1 or 2, characterized by , that the third section (53) of the roof (25) is ring-shaped and surrounds the first section (31) of the roof (25). [4] Airbag module according to claim 3, characterized by , that the second section (42) of the roof (25) is ring-shaped and surrounds the third section (53) of the roof (25). [5] Airbag module according to any one of the preceding claims, characterized by , that the third part (50) of the roof (25) is in snap-fit ​​connection with at least one of the first part (30) of the roof (25) or the second part (40) of the roof (25), preferably with the first part (30) of the roof (25) and the second part (40) of the roof (25). [6] Airbag module according to claim 1 or any of the preceding claims, characterized by , that the third part (50) is a diffuser or includes one. [7] Airbag module according to claim 6, characterized by that the diffuser is made of silicone and preferably has a Shore hardness between 30 and 90 Shore A. [8] Airbag module according to any one of the preceding claims, characterized by , that the lighting arrangement continues to have a light-receiving surface (68a) for receiving light from the light-emitting element (66). [9] Airbag module according to claim 8, characterized by , that the lighting arrangement further comprises a light guiding element (68) for guiding light from the light-emitting element (66) to the third part (50) of the cover (20), wherein the light guiding element (68) comprises the light-receiving surface (68a) and the light guiding element (68) is distinct from the third part (50) of the cover (20). [10] Airbag module according to claim 9, characterized by, that the light guiding element (68) is made of silicone, polymethyl methacrylate (PMMA) or polycarbonate (PC). [11] Airbag module according to any one of claims 1 to 10, characterized by , that the housing (10), the first part (30) of the cover (20) and the airbag cushion (80) are parts of a first subassembly, which preferably also includes the inflation device, and that the second part (40) of the cover (20), the third part (50) of the cover (20) and the light-emitting element (66) are parts of a second subassembly, which is attached to the first subassembly. [12] Airbag module according to one of claims 9 or 10 and according to claim 11, characterized by , that the light guide element (68) is also part of the second subassembly. [13] Method for manufacturing an airbag module according to claim 11 or 12, wherein the assembly of the first sub-assembly is completed before the second sub-assembly or parts of the second sub-assembly are mounted on the first sub-assembly.

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