Decorative unit and airbag module cover

Abstract

A decorative unit (5) designed to be a part of an airbag module cover (60) is described. This decorative unit comprises a first transparent or translucent part (10) having a surface comprising a front surface section (12) and a rear surface section, an illuminating part (30) comprising at least one light emitting element for at least indirectly emitting light to the surface of the first transparent or translucent part (10), and a housing part (40) being made of metal and having a sidewall (41 ) enclosing at least the illuminating part (30). In order to improve the optical appearance of the decorative unit (5), at least one recess (16) extends into the surface of the first transparent or translucent part (10) other than the front surface section (12). This recess (16) has at least a radial fraction and / or section. Further, the housing part (40) comprises at least one front connection section (42), being at least in sections located inside the at least one recess (16) extending into the surface of the first transparent or translucent part (10) (Fig. 10).

Description

[0001] Decorative unit and airbag module cover

[0002] The invention relates to a decorative unit according to the preamble of claim 1 and to an airbag module cover according to claim 10.

[0003] Especially the airbag module cover of a driver airbag module which is located in the hub of the steering wheel often comprises a main part and a decorative unit being attached to this main part. This decorative unit often comprises the logo of the car manufacturer.

[0004] In order to enhance the optical appeal of this decorative unit, it is known to provide this decorative unit with an illuminating part (usually a printed circuit board (PCB) carrying a plurality of LEDs) and with a first transparent or translucent part being illuminated by means of this illuminating part directly or indirectly. This first transparent or translucent part has of course an outer surface which comprises at least a front section (the section that is visible from the inside of the car) and a rear section. So, the decorative unit must at least comprise the just mentioned first transparent or translucent part and the just mentioned illuminating part. Usually, additionally a light guide between the illuminating part and the first transparent or translucent part is provided and often one also needs an endplate rear of the illuminating part. Of course, those elements must be “held together” and thus usually a housing part is provided which can also serve for attaching the whole decorative unit to the main part of the airbag module cover.

[0005] In the prior art a lot of proposals have been made for designing such a decorative unit, especially its housing, but many of those are either complicated to manufacture and to assemble (especially because they are comprised of too many parts) or are aesthetically not satisfying. Starting from this prior art, it is the object of the invention to provide a decorative unit which is easy to manufacture and that is sturdy enough to stay completely attached to the main part of the airbag module cover during deployment of the airbag and that is optically pleasing.

[0006] This task is solved by a decorative unit according to claim 1. An airbag module cover comprising a main part and such a decorative unit is defined in claim 10.

[0007] According to the invention, the decorative unit has several features whose combination makes it possible to provide a decorative unit that has the desired properties.

[0008] According to one feature of the invention, the housing part is made of metal. The use of metal has several advantages over the use of a plastic material: First of all, the housing part can be made light-weight and thin-walled and still provide the necessary sturdiness. Second: by using metal, the housing part can often be single-pieced which reduces the number of assembly steps. The drawback in the use of a metal housing part is that it is often not desired that parts of the metal housing part can be seen after final assembly of the airbag module cover. Thus, measures have to be taken in order to ensure the “invisibility” of the housing part. So, according to another feature of the invention, at least one recess extends into the surface of the first transparent or translucent part in such a way that this recess cannot be seen. This means that this recess extends into a section of the surface of the first translucent or translucent part other than the front surface section. The housing part comprises at least one front connection section that connects the first transparent or translucent part to the housing part. This front connection section extends from a sidewall of the housing part and is at least in sections located inside the at least one recess that extends into the surface of the first transparent or translucent part. Since the recess does not extend from the front surface section of the first transparent or translucent part, the housing part does also not extend to this front surface and so it can be designed such that it is invisible after the decorative units has been mounted to the main part of the airbag module cover. This of course means that the housing part does not encompass the first transparent or translucent part at its front surface. In order to compensate for that, the recess has at least a radial fraction and / or section, such that a force-fit connection in the axial direction is generated between the first transparent or translucent part and the housing part, namely its front connection section.

[0009] By those measures, a decorative unit with a uniform and continuous outside surface is provided. This uniform and continuous outside surface is esthetically pleasing.

[0010] Usually it is preferred that the at least one front connection section extends from the sidewall of the housing part radially inwards such that no extra space radially outside the sidewall of the housing is needed.

[0011] Often it is preferred that the housing part holds all elements of the decorative unit together and for this reason it is often preferred that the housing part further comprises at least one rear connection section being axially spaced from the at least one front connection section. This rear connection section holds the illuminating part at least indirectly. Since the housing part consists of metal, it is preferred that this rear connection section is generated by radial deformation of a housing part precursor as a final assembly step.

[0012] It is possible to provide a single rear connection section, for example in form of a circumferential deformation of the sidewall of the hosing part. Alternatively, a plurality of spaced rear connection sections, especially in form of flaps or ears, can be provided. The same applies to the front connection section.

[0013] As is generally known, a second transparent or translucent part, especially in form of a light guide, can be provided between the illuminating part and the first transparent or translucent part. In one embodiment, the first transparent or translucent part is injection molded to the housing part, such that the at least one recess is formed during the injection molding process, mainly by the front connection section. A very tight and secure connection between the front connection section and the first transparent or translucent part is generated thereby. This allows a robust and precise connection between the first transparent or translucent part and the housing part. In particular, it allows to receive the other internal components without specific attachment to the first transparent or translucent part. Thus, the latter can be free of fixing features (typically a protruding centering pin arranged to be heat stacked) which could impact the light diffusion or homogeneity.

[0014] Alternatively, the first transparent part can be a pre-manufactured part and the at least one front connection section is deformed into the at least one recess. This has the advantage that no sophisticated molding tool is needed.

[0015] Usually, the housing part further comprises attachment ears for attaching the decorative unit to a vehicle part, especially to a main part of an airbag module cover. These attachment ears can be one-pieced with the sidewall of the housing part.

[0016] The invention will now be described by means of preferred embodiments in view of the accompanying figures. The figures show:

[0017] Figure 1 a housing part precursor of a housing part made of metal in a view from the side,

[0018] Figure 2 a view from direction R1 in Figure 1 ,

[0019] Figure 3 a sectional of the housing part precursor of Figure 1 , Figure 4 the housing part precursor of Figure 3 after a first transparent or translucent part has been molded to it,

[0020] Figure 5 the sub-assembly of Figure 4, a light guide and a PCB with LEDs,

[0021] Figure 6 the sub-assembly of Figure 4 with the light guide and the PCB of

[0022] Figure 5 being inserted between the sidewall of the housing part precursor,

[0023] Figure 7 the items of Figure 6 after bending of the rear connection sections of the precursor of the housing part such that the housing part precursor transits to the housing part and the assembly process of the decorative unit is finished,

[0024] Figure 8 the decorative unit of Figure 7 and a section of a main part of an airbag module cover,

[0025] Figure 9 the items shown in Figure 8 after the decorative unit has been inserted into a recessed section of the main part of the airbag module cover of Figure 8,

[0026] Figure 10 the items shown in Figure 9 after the attachment ears of the housing part have been bent in order to secure the decorative element to the main part of the airbag module cover,

[0027] Figure 11 a first transparent or translucent part and the front section of a housing part precursor of a second embodiment in a schematic cross-sectional representation, Figure 12 the items shown in Figure 11 after a section of the first transparent or translucent part has been inserted into the precursor of the housing part,

[0028] Figure 13 the items shown in Figure 12 after the front connection section has been generated,

[0029] Figure 14 a realistic plan view onto the recessed section of a main part of an airbag module cover of a second embodiment of the invention,

[0030] Figure 15 the inner side of the recessed section of Figure 14,

[0031] Figure 16 the decorative unit of the second embodiment in a perspective representation,

[0032] Figure 17 a perspective view onto the airbag module cover of the second embodiment of the invention after the decorative unit of Figure 16 has been mounted in the recessed section of the main part of the airbag module cover shown in Figure 14, and

[0033] Figure 18 essentially what is shown in Figure 17 in a cross-sectional representation.

[0034] The invention will first be described in detail by means of the assembly process of a schematically shown first embodiment in view of Figures 1 to 10.

[0035] Figures 1 to 3 show a housing part precursor 40’ that transforms to a housing part 40 during the assembly process. This housing part precursor 40’ comprises a sidewall 41 which is in the shape of a hollow cylinder and a front connection section 42 extending from a front end section 41a of the sidewall 41 in radial direction DR to the inside (see especially Figures 2 and 3). The front connection section 42 is in form of a continuous ring, but in other embodiments, a plurality of separate front connection sections could be provided, wherein in this case it is also preferred that those separate front connection sections extend to the inside. The housing part precursor 40’ further comprises parts 44’ (in the form of ears) extending from the rear end 41 b of the sidewall 41 substantially in axial direction, and attachment ears 46, which do also extend from the rear end section 41 b of the sidewall 41. The parts 44’ transform to rear connection sections 44 during the assembly process as will be seen later. In the embodiment shown, the parts 44’ and the attachment ears 46 do not only extend from the rear end section 41 b of the side wall, but from the rear end edge of sidewall 41 .

[0036] In a first assembly step, a first transparent or translucent part 10 is molded to the front end section of the housing part precursor 40’, meaning to the front end section 41 a of the sidewall and the front connection section 42, in such a way that the front connection section 42 extends into this first transparent or translucent part 10. The first transparent or translucent part 10 has - of course - a surface which comprises a rear surface section 11 , a front surface section 12 and a side surface section 14. Because the first transparent or translucent part 10 is molded to the housing part precursor 40’, especially around the front connection section 42, a recess is formed which extends from the surface of the first transparent or translucent part and which accommodates the front connection section 42. In other words: This recess is or comprises the negative form of the front connection section 42 and thus, since the front connection section 42 extends radially inwards, the recess also extends radially into the first transparent or translucent part 10 from its surface, here from its side surface section 14. It is not necessary that this recess 16 (and the front connection section 42) extends completely in radial direction, but it must have a radial extending part or a radial extending fraction such that a force- fit between the front connection section 42 and the first transparent or translucent part 10 is generated not only in radial direction, but also in axial direction. In the subsequent assembly step or steps, a second transparent or translucent part in form of a light guide 20 and an illuminating part 30 - a PCB which carries at least one light emitting element, usually a plurality of LEDs 32 - is inserted from the rear end side of the sidewall 41 , such that a front surface of the light guide 20 is in contact or at least in close proximity to the rear surface section 11 of the first transparent or translucent part 10. Providing such a second translucent or transparent part will often be preferred but might not be mandatory in all embodiments. In any case, an illuminating part needs to be provided in such a way that light emitted by this illuminating part is directly or indirectly fed into the first transparent or translucent part 10, usually its rear surface section 11.

[0037] In a next step, the parts 44’ or the housing precursor are bent inwards to form the rear connection sections 44 of the housing part 40. The assembly process of the decorative unit 5 is now finished.

[0038] Next, this decorative unit 5 is mounted to the main part 50 of an airbag module cover in particular for driver side applications. This main part 50 of the airbag module cover comprises a basic body 52 which is a molded plastic part, and optionally a covering 54 which usually consists of leather or artificial leather. The main part 50 of the airbag module cover comprises a recessed section 56 for accommodating the decorative unit 5. Through-holes 58 for the attachment ears 46 of the housing part 40 and a through-hole for the electric cable 34 extending from the illuminating part 30 are provided, as is generally known in the art.

[0039] As shown in Figures 9 and 10, the decorative unit 5 is inserted into the recessed section 56, from the outside of the main part of the airbag module cover, such that sections of the attachment ears 46 extend through the just mentioned through- holes 58. Subsequently, those attachment ears 46 are bent in order to secure the decorative unit 5 to the main part 50 of the airbag module cover, such that the assembly of this airbag module cover 60 is completed. The attachment ears can additionally be riveted, heat stacked, screwed or glued to the basic body 52. The recess provides a large bearing surface for the decorative unit 5 favorable for a robust and simple attachment. Such a recessed section 56, when it requires an insertion of the decorative unit 5 from the outside of the airbag module covering is particularly suitable for airbag module covers wrapped with a covering 54 as it allows to easily receive and hide the ends of the covering 54.

[0040] Now, a second embodiment is described in view of Figures 11 to 13. Even though it will often be preferred to mold the first transparent or translucent part 10 to the housing 40 or its precursor 40’, it is also possible to provide a pre-manufactured first transparent or translucent part 10 which already comprises the at least one recess. In this case, it is for example possible to create the front connection section 42 (or a plurality of front connection sections) by deforming the housing a part 42’ of the precursor 40’, for example by means of crimping, as is shown in Figures 12 and 13.

[0041] Figures 13 to 18 show a third embodiment which is very similar to the first embodiment, but shown in a more realistic representation. In Figure 14 one sees a central section of a main part 50 of an airbag module cover with a recessed section 56. One can see the through-holes 58 for the attachment ears, as well as a through-hole 57 for a cable which usually needs to be provided for delivering electricity to the illuminating part 30 of the decorative unit 5.

[0042] As can be seen from Figure 15 which is a rear view to the recessed section 56, accommodations 59 for the attachment ears can be provided in order to even better secure the decorative unit 5 to the main part of the airbag module cover.

[0043] In Figure 16 a complete decorative unit 5 is shown, Figure 17 shows the decorative unit 5 being accommodated in the recessed section 56 and being secured to the main part of the airbag module cover. Figure 18 shows the same as Figure 17, but in a cross sectional view. In this embodiment, the decorative unit further comprises an endplate 35 on the rear of the illuminating part 30. This endplate 35 advantageously protect the back side of the illuminating part 30 and can also support in a better way optional sealing elements. Sealing elements or features can be provided against moisture as well as to avoid light leakage by the back side of the decorative element 5. Another difference to the first embodiment is that the front connection section of the housing part extends partly into the rear surface section of the first transparent or translucent part 10.

[0044] One can see from the described embodiments that the decorative unit can be easily assembled form a minimum of parts, can be designed very sturdy because of the full metal housing part and is optically pleasing because only the first transparent or translucent part is visible from the inside of the car. The first transparent or translucent part usually shows on its front surface section the emblem of the car manufacturer.

[0045] List of reference numbers

[0046] 5 decorative unit

[0047] 10 first transparent or translucent part

[0048] 11 rear surface section

[0049] 12 front surface section

[0050] 14 side surface section

[0051] 16 recess in side surface (one annular groove, or plurality of recesses)

[0052] 20 second translucent or transparent element (light guide)

[0053] 30 illuminating part (PCB with LEDs)

[0054] 32 LED

[0055] 34 cable

[0056] 35 endplate

[0057] 40 housing part

[0058] 40’ housing part precursor

[0059] 41 sidewall

[0060] 41 a front end section of sidewall

[0061] 41 b rear end section of sidewall

[0062] 42 front connection section

[0063] 42’ part of housing part precursor being crimped to front connection section

[0064] 44 rear connection section

[0065] 44’ part of housing part precursor being bent to the rear connection section

[0066] 46 attachment ear

[0067] 50 main part of airbag module cover

[0068] 52 basic body

[0069] 54 leather covering

[0070] 56 recessed section of airbag module cover for accommodating decorative unit

[0071] 57 through-hole for cable

[0072] 58 through-hole for attachment ear

[0073] 59 accommodation for attachment ear

[0074] 60 airbag module cover DA axial direction

[0075] DR radial direction

Claims

Claims1 . Decorative unit (5) designed to be a part of an airbag module cover (60), comprising: a first transparent or translucent part (10) having a surface comprising a front surface section (12) and a rear surface section (11 ), said front surface section (12) defining a first end of the decorative unit (5) in an axial direction (DA), an illuminating part (30) comprising at least one light emitting element for at least indirectly emitting light to the surface of the first transparent or translucent part (10) other than the front surface section (12), a housing part (40) having a sidewall (41 ) enclosing at least the illuminating part (30), characterized in that at least one recess (16) extends into the surface (14) of the first transparent or translucent part (10) other than the front surface section, said recess having at least a radial fraction and / or section, the housing part (40) is made of metal, the housing part (40) comprises at least one front connection section (42), said front connection section (42) being at least in sections located inside the at least one recess (16) extending into the surface (14) of the first transparent or translucent part (10).

2. Decorative unit according to claim 1 , characterized in that the at least one front connection section (42) extends from the sidewall (41 ) of the housing part (40) inwards.

3. Decorative unit according to claim 1 or claim 2, characterized in that the housing part (40) further comprises at least one rear connection section (44) being axially spaced from the at least one front connection section (42) and holding the illuminating part (30) at least indirectly.

4. Decorative unit according to claim 3, characterized in that the at least one rear connection section (44) is generated by plastic deformation of at least a part (44’) of a housing part precursor (40’) from which the housing part (40) is made.

5. Decorative unit according to any one of claims 3 or 4, characterized in that a plurality of rear connection sections (44) is provided, each rear connection section (44) being an inwardly bent section of the housing.

6. Decorative unit according to any one of the preceding claims, characterized in that a second transparent or translucent part (20) is provided between the illuminating part (30) and the first transparent or translucent part (10).

7. Decorative unit according to any one of the preceding claims, characterized in that the first transparent or translucent part (10) is injection molded to the housing part (40), such that the at least one recess (16) is formed during the injection molding process.

8. Decorative unit according to any one of the claims 1 to 6, characterized in that the first transparent or translucent part (10) is a pre-manufactured part and the at least one front connection section (42) is deformed into the at least one recess (16).

9. Decorative unit according to any one of the preceding claims, characterized in that the housing part (40) further comprises attachment ears (46) for attaching the decorative unit (5) to a vehicle part, especially to a main part (50) of an airbag module cover.

10. Airbag module cover (60) comprising a main part (50) and a decorative unit according (5) to claim 9 being attached to the main part (50) by means of the attachment ears.

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