DE102022121127A1 - Airbag module with light exit surface - Google Patents

Abstract

An airbag module with a housing (10) and a cover (20) is described. The cover (20) includes a roof (25) with an outer surface, and the cover (20) has a first part (30) which includes a first section (31) of the roof. At least one light-emitting element (66) is located outside a receiving space for an airbag. This light-emitting element (66) has an active state in which it emits light. Furthermore, a lighting arrangement is provided with a light exit surface (53a), which forms a section of the outer surface of the roof (25), so that the light exit surface (53a) emits light to the outside when the light-emitting element (66) is in its active state. In particular to simplify assembly, the cover (20) also comprises a second part (40) and a third part (50). The second part is located outside the receiving space and comprises a second section (42) of the roof which covers the light-emitting element (66), the second section (42) of the roof being at least partially spaced from the first section (31) of the roof . The third part (50) differs from the first part (30) and comprises a third section (53) of the roof (25) which fills the gap between the first section (31) of the roof and the second section (42) of the roof and the light emitting surface (53a).

Description

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

The invention primarily relates to so-called driver airbag modules, which are designed and intended for mounting on a steering wheel body of a vehicle steering wheel. For this reason, reference is primarily made to such a driver airbag module, but 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.

A driver airbag module typically consists of a housing and a cover, so that the housing and the cover enclose a receiving space for an airbag cushion. Furthermore, an inflation device is provided, which is usually attached to a bottom wall of the housing. The cover, of course, includes a roof spanning the housing, which roof has a visible exterior 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 portion of the roof by at least one breaking line and at least one hinge.

In most cases, the cover further includes a sidewall that is connected to the housing, often by a snap connection. The cover is usually a plastic injection molded part.

In order to improve the visual appearance of the cover (namely its roof), it is known to provide a lighting arrangement having a light emitting surface which forms a portion of the outer surface of the roof of the cover.

This is how it is, for example, from the EP 1 973 767 A1 It is known to provide a light-emitting element (one could also refer to it as a “light-generating element”) outside the receiving space for the airbag cushion and to direct the light of the light-emitting element via a light guide to a central section of the roof which has a light-emitting surface. The problem is that the light guide is usually located in the deployment path of the airbag cushion.

Also the US 6,848,706 shows an airbag module whose roof has a light exit surface. Here the lighting arrangement is located completely outside the receiving space of the airbag cushion, so that this lighting arrangement does not hinder the deployment of the airbag cushion.

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

This task is solved by an airbag module with the features of claim 1. A method for producing such an airbag module is specified in claim 13.

The process 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 special machinery. It has been found that it can be difficult to ensure that the elements of the lighting assembly are not damaged during this process. According to the invention, the airbag module is therefore constructed in such a way that the airbag module comprises a first subassembly which includes the airbag cushion packed in the receiving space and the elements surrounding this receiving space, this subassembly being able to be manufactured before an element of the lighting arrangement is mounted on it.

To achieve this, the cover may not consist of a single part (as is usual 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 receiving space for the airbag. This first part may include a first portion of the roof having at least one door that can be opened by the deploying airbag cushion. The second part can be located outside the receiving space and includes a second roof section that covers the light-emitting element. This second section of the roof can be spaced at least in sections from the first section of the roof. Furthermore, the cover may comprise a third part that is different from the first part. This third part may include a third portion of the roof that fills the gap between the first portion of the roof and the second portion of the roof, and may include the light emitting surface.

Since the second part of the cover must generally have different properties than the first part and the second part (in particular, it must be at least partially transparent or translucent), it is often preferred that the first part of the cover, the second part of the cover and the third part of the cover are separate parts. Old natively, the third part can be molded onto the second part.

In a visually and mechanically preferred geometry, the third section of the roof may be annular and surround the first section of the roof, and the second section of the roof may also be annular and surround the third section of the roof. With this geometry, the third roof section can additionally form a seal between the first roof section and the second roof section.

In order to facilitate assembly, it may be preferred that the third roof section is in a snap connection with at least one of the two roof sections, preferably with the first and the second roof section.

As already mentioned, the third section of the roof can include the light exit surface. For this reason, the third part may preferably be or comprise a light diffuser. A preferred material for the light diffuser is silicone, particularly silicone with a Shore hardness between 30 and 90 Shore A. This facilitates the assembly process and ensures a tight seal.

Since the third part does not generate light, the lighting arrangement typically includes a light-receiving surface for receiving light from the light-emitting element. Although it would in principle be possible to feed the light generated by the light-emitting element directly into the third part of the cover, for geometric reasons and to optimize the light scattering homogeneity it can often be preferred that the lighting arrangement further includes a separate light-guiding element for guiding the light from the light-emitting element Element for the third part of the cover, this light-guiding element comprising the light-receiving surface. This light-guiding element can be made of silicone, polymethyl methacrylate (PMMA) or polycarbonate (PC), for example.

As already mentioned, the housing, the first part of the cover and the airbag can be parts of a first subassembly. This first subassembly may additionally contain the inflator. The second part of the cover, the third part of the cover and the light emitting element may be parts of a second subassembly that is attached to the first subassembly. If a light guide element is used, this can also be part of the second subassembly.

In a preferred method of manufacturing an airbag module, assembly of the first subassembly may be completed before the second subassembly or portions of the second subassembly are assembled to the first subassembly to avoid damage to a portion of the second subassembly. Preferably, the entire second assembly can be completed before being assembled to the first assembly.

• 1 alle Elemente einer ersten Unterbaugruppe der beschriebenen Ausführungsform des Airbagmoduls,
• 2 alle Elemente einer zweiten Unterbaugruppe der beschriebenen Ausführungsform des Airbagmoduls,
• 3 die vollständig montierte erste Unterbaugruppe und die vollständig montierte zweite Unterbaugruppe in einem Zustand, in dem die zweite Unterbaugruppe noch nicht an der ersten Unterbaugruppe montiert ist,
• 4 das vollständig montierte Airbagmodul (die erste Unterbaugruppe aus 3 und die zweite Unterbaugruppe aus 3, die an der ersten Unterbaugruppe montiert ist),
• 5 das Detail D aus 4, wobei das Airbagkissen nicht dargestellt ist, und
• 6 eine perspektivische Ansicht des Airbagmoduls.

The invention will now be described in more detail using preferred embodiments using the figures. The figures show:

• 1 all elements of a first subassembly of the described embodiment of the airbag module,
• 2 all elements of a second subassembly of the described embodiment of the airbag module,
• 3 the fully assembled first subassembly and the fully assembled second subassembly in a state in which the second subassembly is not yet assembled on the first subassembly,
• 4 the fully assembled airbag module (the first subassembly 3 and the second subassembly 3 , which is mounted on the first subassembly),
• 5 the detail D 4 , with the airbag cushion not shown, and
• 6 a perspective view of the airbag module.

• Ein Gehäuse 10 und ein erster Teil 30 der Abdeckung definieren eine Aufnahme für ein Airbagkissen 80, das durch einen Gasgenerator 70 aufgeblasen werden kann. Dieser Gasgenerator 70 ist, wie aus dem Stand der Technik bekannt, an der Bodenwand 11 des Gehäuses 10 befestigt. Der von dem Gehäuse 10 und dem ersten Teil 30 der Abdeckung eingeschlossene Raum wird auch als Aufnahmeraum für das Airbagkissen bezeichnet.

A primary concept of the invention is that the airbag module has two subassemblies, with one subassembly (the first subassembly) comprising all of the elements necessary to form a “conventional” airbag module. The elements of this first subassembly are in shown:

• A housing 10 and a first part 30 of the cover define a receptacle for an airbag cushion 80 that can be inflated by a gas generator 70. This gas generator 70 is, as is known from the prior art, 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 receiving space for the airbag cushion.

The housing 10 is largely designed like a conventional housing, that is, it consists of a housing side wall 14 and the bottom wall 11 just mentioned. An opening 12 for the inflator is provided in the middle of the bottom wall 11. In addition, a plurality of 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 includes a main body 72 and a mounting flange 74 for attaching the gas generator 70 to the bottom wall 11.

A fastening section 15 extends radially outward from the upper end of the side wall 14. Instead of one annular fastening section 15, several fastening sections 15 could also be provided.

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.

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

shows all elements of a second subassembly of the airbag module. In the described embodiment, this second subassembly comprises the following elements: a second cover part 40 and a third cover part 50 are provided. In this embodiment, the second part 40 of the cover exclusively forms a second section 42 of the roof and the third part 50 of the cover exclusively forms a third section 53 of the roof. For this reason, the terms “second portion of the cover” and “second portion of the roof” may be used interchangeably, and the terms “third portion of the coverage” and “third portion of the roof” may also be used interchangeably.

The second part 40 of the cover is typically an injection molded part made from a standard opaque airbag module cover material, for example thermoplastic olefin (TPO) and/or thermoplastic elastomer (TPE), but another material may also be used as this second Part 40 of the cover lies outside the receiving space that accommodates the airbag cushion 80.

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

Both the second part 40 and the third part 50 are annular, so that the second part 40 forms an outer ring and the third part 50 forms an inner ring. Connecting means are provided so that the third part 50 can be attached to the second part 40, it being preferred that these fastening devices function without adhesive or the like. In this embodiment, these fastening 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 molded onto the third part 50 or vice versa.

The third part 50 also includes fasteners for securing the third part 50 to the first part 30 of the cover.

• - Zur Erzeugung des Lichts ist eine elektronische Einheit 65 vorgesehen, die eine ringförmige Leiterplatte (PCB) 64 und eine Vielzahl von Leuchtdioden (LEDs) 66 als lichtemittierende Elemente (die auch als lichterzeugende Elemente bezeichnet werden könnten) umfasst. Die LEDs 66 sind mechanisch und elektrisch mit der Leiterplatte 64 verbunden.
• - Um das von den LEDs 66 erzeugte Licht zum dritten Teil 50 der Abdeckung (dem Diffusor) zu leiten, ist ein Lichtleitelement 68 vorgesehen, das einen rohrförmigen Abschnitt mit einer Lichtaufnahmefläche 68a aufweist.
• - Schließlich dient ein Befestigungselement 62 mit einem Flanschabschnitt 62a und einem Rohrabschnitt 62b zur Befestigung der elektronischen Einheit 65 und des Lichtleitelements 68 an dem Befestigungsabschnitt 15 der Gehäuseseitenwand.

When the airbag module is fully assembled, the upper surface of the third part 50 forms a light exit surface 53a of the roof of the cover of this airbag module. Since the third part 50 does not produce light, a lighting subassembly 60 is provided to provide the third part 50 with light. In the embodiment shown, this lighting subassembly 60 includes three elements:

• - To generate the light, an electronic unit 65 is provided, which includes an annular 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 circuit board 64.
• - In order to guide 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 tube section 62b serves to fasten the electronic unit 65 and the light-guiding element 68 to the fastening section 15 of the housing side wall.

shows the first subassembly consisting of the in elements shown, and the second subassembly, which consists of the in elements shown. 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-producing, light-conducting or light emitting parts. The first subassembly is assembled like a conventional airbag module, so no further explanation is required.

Regarding the second subassembly: The third part 50 is attached to the upper ends of the tube section 62b of the fastening element 62 and the light-guiding element 68, so that the third part 50 is in contact with or in close proximity to the upper end of the light-guiding element 68, so that the in The light entering the light-guiding element 68 at the light-receiving surface 68a is guided 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 with its upper end to the third part 50 of the cover as described above and with its lower end to the flange portion 62a of the fastening 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 exit surface 53a of the third part 50.

shows the fully assembled airbag module after the second subassembly has been attached to the first subassembly. In this last assembly step, the flange section 62a is attached to the assembly section 15 and the third part 50 of the cover is snapped onto the first part 30 of the cover.

shows detail D , but without the airbag cushion 80. It can be seen that the light exit surface 53a, the outer surface of the roof 25a and the second section of the roof 42 are flush and form a single continuous external visible surface.

again shows the airbag module and in particular its roof 25. You can see the annular structure of the third part 50 and the second part 40. 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.

The light emitting elements (the LEDs 66) are hidden under the second portion 42 of the roof, but when in their active light emitting state, at least some of that light is radiated from the light emitting surface 53a.

Reference symbol list

10

Housing

11

floor wall

12

Opening for the inflator

13

Opening for cover hook

14

Housing side wall

15

Fastening section of the housing side wall

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

lighting subassembly

62

fastener

62a

flange section

62b

pipe section

63

screw

64

Circuit board

65

electronic unit

66

LED (light emitting element)

68

Light guide element

68a

Light receiving surface

70

Gas generator

72

Gas generator main body

74

mounting flange

80

Airbag cushion

QUOTES INCLUDED IN THE DESCRIPTION

This list of documents listed by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• EP 1973767 A1 [0006]
• US 6848706 [0007]

Claims (13)

Airbag module with a housing (10), a cover (20) which comprises a roof (25) with an outer surface, the cover (20) having a first part (30) which comprises a first section (31) of the roof, an airbag cushion (80) located within a receiving space enclosed by the housing (10) and/or the first part (30) of the cover, an inflator for inflating the airbag cushion, at least one light-emitting element (66), the is arranged outside the receiving 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) which forms a portion of the outer surface of the roof (25), so 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) which is located outside the receiving space and a second portion (42) of the roof covering the light-emitting element (66), the second portion (42) of the roof being at least partially spaced from the first portion (31) of the roof, a third portion (50) which is different from the first part (30), the third part (50) comprising a third section (53) of the roof (25) which forms the gap between the first section (31) of the roof and the second section (42) of the roof fills and has the light-emitting surface (53a). Airbag module Claim 1 , characterized in 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. Airbag module according to one of the Claims 1 or 2 , characterized in that the third section (53) of the roof is annular and surrounds the first section (31) of the roof. Airbag module Claim 3 , characterized in that the second section (42) of the roof is annular and surrounds the third section (53) of the roof. Airbag module according to one of the preceding claims, characterized in that the third part (50) of the roof is in snap connection with at least one of the first part (30) of the roof or the second part (40) of the roof, preferably with the first part (30 ) of the roof and the second part (40) of the roof. Airbag module Claim 1 or one of the preceding claims, characterized in that the third part (50) is or comprises a diffuser. Airbag module Claim 6 , characterized in that the diffuser is made of silicone and preferably has a Shore hardness between 30 and 90 Shore A. Airbag module according to one of the preceding claims, characterized in that the lighting arrangement further comprises a light receiving surface (68a) for receiving light from the light emitting element (66). Airbag module Claim 8 , characterized in 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, the light-guiding element (68) comprising the light-receiving surface (68a) and the light-guiding element (66 ) is different from the third part (50) of the cover. Airbag module Claim 8 , characterized in that the light-guiding element consists of silicone, polymethyl methacrylate (PMMA) or polycarbonate (PC). Airbag module according to one of the Claims 1 until 10 , characterized in 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 additionally comprises the inflator, and that the second part of the cover, the third part (40) of the cover and the light emitting element (66) are parts of a second subassembly which is attached to the first subassembly. Airbag module according to one of the Claims 9 or 10 and after Claim 11 , characterized in that the light-guiding element is also part of the second subassembly. Method for producing an airbag module Claim 11 or 12 , wherein assembly of the first subassembly is completed before the second subassembly or parts of the second subassembly are assembled to the first subassembly.

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