Method for producing covers for airbag modules

Abstract

The invention relates to a method for producing covers (1) for airbag modules. The covers (1) each comprise a receiving region (2) for at least one decorative element that is visible to a passenger in a mounted state of a cover (1). The covers (1) are each manufactured between a first nozzle-size mould half (5) and a second ejection-side mould half (6) of an injection mould (4). The receiving regions (2) of covers (1) of a first batch are adapted by at least one changeable insert (5A or 6A) or by changeable inserts (5A, 6A) which is / are inserted into the first mould half (5) and / or into the second mould half (6), respectively, and the receiving regions (2) of covers (1) of at least one second batch are adapted to differently designed decorative elements (10) to be inserted into the receiving regions (1) by inserting at least one further changeable insert or further changeable inserts.

Description

[0001] Method for manufacturing covers for airbag modules

[0002] The invention relates to a method for producing covers of airbag modules according to the type defined in more detail in the preamble of patent claim 1.

[0003] EP 2 687 413 A1 discloses a cover for an airbag module, which comprises a decorative element with a front side and a back side. The front side of the cover is visible when the cover is connected to the airbag module. Furthermore, a mounting element is provided, which is arranged on the back side of the decorative element and is intended for mounting the cover to a housing of the airbag module. The mounting element is formed by overmolding the decorative element and is connected directly to the decorative element.

[0004] Typically, such covers are manufactured using plastic injection molding, resulting in high tooling costs for a variety of different covers and decorative elements.

[0005] The object of the present invention is to provide a method by means of which covers of airbag modules for differently designed decorative elements can be produced in a simple and cost-effective manner.

[0006] According to the invention, this object is achieved by a method having the features of patent claim 1.

[0007] By means of the method according to the invention, covers for airbag modules are produced between a first nozzle-side mold half and a second ejector-side mold half of an injection molding tool. The covers each have a receiving area for at least one decorative element visible to a passenger when the cover is assembled.

[0008] According to the invention, the receiving areas of covers of a first series are adapted to differently designed decorative elements to be inserted into the receiving areas by at least one interchangeable insert which is inserted into the first tool half or into the second tool half, and the receiving areas of covers of at least a second series are adapted to differently designed decorative elements to be inserted into the receiving areas by replacing the interchangeable insert with a further interchangeable insert.

[0009] In addition, it is possible for the receiving areas of covers of the first series to be adapted to differently designed decorative elements to be inserted into the receiving areas by means of interchangeable inserts which are respectively inserted into the first tool half and into the second tool half, and for the receiving areas of covers of at least a second series to be adapted to differently designed decorative elements to be inserted into the receiving areas by replacing the interchangeable inserts with further interchangeable inserts.

[0010] The alternatives of the inventive method ensure that different decorative elements or emblems important for brand communication can be easily and cost-effectively integrated into largely identically designed covers using various interchangeable inserts in the airbag cap tool. This achieves the greatest possible differentiation of the covers with the best possible one-time effort, i.e., while simultaneously keeping development and tooling costs low.

[0011] In other words, the method according to the invention allows different brand emblems to be integrated into covers of airbag modules in a cost-effective manner, which only differ from one another in their receiving areas.

[0012] The receiving areas of the covers can each be arranged within tear lines created by the tool halves and / or by the interchangeable inserts in the covers, along which the covers tear open when the airbag module is deployed, revealing an opening for an airbag. Since the different design of the receiving areas does not influence the layout of the tear lines of the covers, costly development costs are avoided, which are always incurred for the proper functioning of an airbag module. The covers in the receiving areas can each be designed with at least one opening. Plug-in elements of decorative elements can be inserted into these openings to firmly connect a decorative element to a cover.Such a plug-in element of a decorative element can project beyond a rear side of the decorative element, which, when the decorative element is mounted, faces a front side of the receiving area of ​​the cover. This allows a decorative element to be attached to a cover with little effort and preferably with a desired orientation.

[0013] The front sides of the cover receiving areas, each facing the back of a decorative element to be inserted into a cover receiving area, can be designed with a topology or with a crown. This topology or crown makes it possible to support a decorative element from the back and prevent deformation of the element and the resulting operating noise, which could be caused, for example, by a so-called "clicking frog" effect. This is particularly advantageous when the front side of a decorative element is made of a thin metal sheet.

[0014] In a further advantageous variant of the method according to the invention, at least the covers of the first series are each formed with at least one connection area for decorative elements that can be illuminated at least in part. An illuminable decorative element can be connected to an on-board electrical and control system of a vehicle via such a connection area.

[0015] If at least the plug-in elements of the decorative elements are made of plastic and each pass through openings in the receiving areas of the covers, in a further variant of the method according to the invention, the plug-in elements are each hot-stitched to the backs of the covers to firmly connect the decorative elements to the covers or welded to the covers by ultrasonic welding. If at least the plug-in elements of the decorative elements are made of metal and each pass through the openings in the receiving areas of the covers, in a further variant of the method according to the invention that can be carried out with little effort, the free ends of the plug-in elements on the backs of the covers are each bent over or riveted to the covers to firmly connect the decorative elements.

[0016] At least the front sides of the covers can be covered with a layer of synthetic or natural leather. This makes it easy to conceal any unwanted visible tool separations in the area of ​​the covers, making them invisible to a passenger in the vehicle.

[0017] In addition to this or alternatively, it is also possible for the covers to be designed with graining or design edges, at least in the area of ​​their front sides, in order to conceal desired visible tool separations.

[0018] Furthermore, it can be provided that the covers in the receiving areas are each designed with a component weight that is adapted to the component weight of the decorative element to be attached to it. The adaptation can be provided in such a way that the sum of the component weights of the covers of the series and the various decorative elements associated with them is at least approximately equal. This allows weight differences of the various decorative elements to be attached to be easily compensated for by the injection molding structure in order to achieve uniform tearing behavior when the airbag is deployed.

[0019] In principle, it is possible to design the receiving areas as recesses in the covers. In other words, the front of the cover is then set back in the receiving area relative to the rest of the front of the cover, giving the receiving area an at least approximately bowl-shaped configuration. An outer peripheral area of ​​the receiving area can be adapted to the outline of a decorative element to be arranged therein and can be designed, for example, as circular, triangular, square, polygonal, or trapezoidal, or can also be manufactured with any other suitable outline shape for accommodating a decorative element.

[0020] Further advantages and advantageous developments of the invention emerge from the patent claims and the exemplary embodiments described in principle with reference to the drawing.

[0021] It shows:

[0022] Fig. 1 is a front view of a cover of an airbag module with a receiving area for a decorative element visible to a passenger when the cover is in the assembled state;

[0023] Fig. 2 is a rear view of the cover according to Fig. 1;

[0024] Fig. 3 is a highly simplified longitudinal sectional view through an injection molding tool intended for producing the cover according to Fig. 1;

[0025] Fig. 4 is a three-dimensional partial view of a receiving area of ​​a possible embodiment of the cover according to Fig. 1;

[0026] Fig. 5 is a partial longitudinal sectional view through the receiving area of ​​the cover according to Fig. 4, wherein a decorative element is inserted into the receiving area;

[0027] Fig. 6 is a view corresponding to Fig. 4 of the receiving area of ​​the cover according to Fig. 4, into which a decorative element is inserted;

[0028] Fig. 7 is a representation corresponding to Fig. 4 of a further embodiment of the receiving area of ​​the cover according to Fig. 1;

[0029] Fig. 8 is a view corresponding to Fig. 5 of the cover according to Fig. 7, into which a decorative element is inserted;

[0030] Fig. 9 is a view of the injection molding tool corresponding to Fig. 3, into which additional interchangeable inserts are inserted on the ejector side and the nozzle side; Fig. 10 is a schematic rear view of another embodiment of a cover manufactured using the interchangeable inserts shown in Fig. 9;

[0031] Fig. 11 is a representation corresponding to Fig. 9 of the injection molding tool for producing a cover shown highly schematically in Fig. 12;

[0032] Fig. 12 is a representation corresponding to Fig. 10 of a further embodiment of a cover;

[0033] Fig. 13 is a representation corresponding to Fig. 10 of another possible embodiment of the cover;

[0034] Fig. 14 is a representation of the injection molding tool corresponding to Fig. 9, into which further interchangeable inserts are inserted, via which a crack line can be produced in some areas;

[0035] Fig. 15 is a view corresponding to Fig. 10 of a cover made with the interchangeable inserts according to Fig. 14;

[0036] Fig. 16 is a representation of the injection molding tool corresponding to Fig. 14, into which further interchangeable inserts are inserted for producing an embodiment of a cover shown in more detail in Fig. 17;

[0037] Fig. 17 is a representation corresponding to Fig. 15 of a further embodiment of a cover, in which the tear line in the receiving area has a course which differs from the course of the tear line of the cover according to Fig. 15;

[0038] Fig. 18 is a view corresponding to Fig. 10 of a further embodiment of the cover;

[0039] Fig. 19 is a simplified detailed view of an illuminable decorative element;

[0040] Fig. 20 is a rear view of the decorative element according to Fig. 19;

[0041] Fig. 21 is a front view of the decorative element according to Fig. 19, which is placed on a lens; and

[0042] Fig. 22 is a sectional view through the decorative element according to Fig. 19.

[0043] Fig. 1 shows a front view of a cover 1, which is an airbag cap of an airbag module not shown in detail in the drawing. Such an airbag module is integrated, among other things, into a vehicle's steering wheel to protect a driver. The cover 1 forms the front side of a housing of the airbag module and is placed on a lower part of the housing and firmly connected to it.

[0044] Additionally, a rear view of the cover 1 is shown in Fig. 2.

[0045] The cover 1 is formed within a circle K, which is identified in more detail in Fig. 1 and Fig. 2, with a receiving area 2 which is intended to receive a decorative element, such as a brand emblem or the like. The circular shape of the receiving area 2 is chosen here merely for illustrative purposes and, depending on the respective application, can be arranged within a different closed line consisting of curved and / or straight lines. When the cover 1 is installed, the decorative element is attached to the front side 3 of the cover 1 within the receiving area 2 and is visible to a passenger.

[0046] Fig. 3 shows a schematic longitudinal sectional view of an injection molding tool 4, which comprises a nozzle-side tool half 5 and an ejector-side tool half 6. To produce the cover 1 and the receiving area 2, so-called interchangeable inserts 5A and 6A are inserted into both the nozzle-side tool half 5 and the ejector-side tool half 6. Using the interchangeable inserts 5A, 6A, the receiving area 2 can be designed or constructed differently with little effort and in a cost-effective manner, and can be adapted to differently designed decorative elements without having to modify the remaining area of ​​the cover 1.

[0047] In addition, it is also possible for the receiving area 2 to be designed or constructed differently using only one of the interchangeable inserts 5A or 6A.

[0048] Fig. 4 shows a possible embodiment of the receiving area 2 of the cover 1, which is designed with openings 7 and with a defined topology 8. The topology 8 of the receiving area 2 of the cover 1 according to Fig. 4 comprises webs 9 extending in the circumferential direction U and also in the radial direction R of the receiving area 2, which webs are provided for supporting a decorative element 10 in the mounted state, shown in more detail in Fig. 5 and Fig. 6. The decorative element 10 has plug-in elements 11, which are inserted into the openings 7 starting from the front side 3 of the cover 1 during assembly of the decorative element 10 on the cover 1 according to Fig. 4. When the decorative element 10 is mounted, the plug-in elements 11 pass through the openings 7 of the cover 1 and project beyond the rear side 12 of the cover 1 in the vertical direction Z of the cover.The free ends 13 of the plug-in elements 11 are then bent over in order to firmly connect the decorative element 10 to the cover 1.

[0049] Fig. 7 shows a representation corresponding to Fig. 4 of a further embodiment of the cover 1 or of the receiving area 2, which is formed with a plurality of openings 14, into which, in turn, plug-in elements 11 of the decorative element 10 can be inserted in the manner shown in more detail in Fig. 8 or can be partially plugged through these. The decorative element 10 according to Fig. 8 comprises a decorative upper side 15, which is attached to a carrier element 16, preferably made of plastic, which is provided with the plug-in elements 11.

[0050] Furthermore, it can also be provided that the decorative element 10 is made entirely of plastic and is painted, PVD-coated, made of a solid-colored material, or the like, at least on its decorative upper side 15. Furthermore, it is also possible for an upper side of the decorative element 10 to be made of metal, such as aluminum or the like, which is glued to a plastic support element.

[0051] The plug elements 11 of the support element 16 are first inserted with their free ends 13 into the openings 14 and are clipped, hot-stitched, welded, or firmly connected to the cover 1 on the rear side 12 of the cover 1 in another suitable manner. In Fig. 8, a plug element and its free end before hot-stitching are each identified in more detail by the reference numerals 11 and 13, whereas a plug element and its hot-stitched free end are each identified by the reference numerals 11A and 13A.

[0052] Additionally, it is possible for the decorative element 10 according to Fig. 8 to be firmly connected to the cover 1 by bending the free ends 13 of the plug-in elements 11 or by hot-staking the free ends 13 of the plug-in elements 11. Alternatively, it is also possible to firmly connect the plug-in elements 11 to the cover 1 by ultrasonic welding.

[0053] Fig. 9 shows a representation of the injection molding tool 4 corresponding to Fig. 3, wherein further interchangeable inserts 59A and 69A are inserted into the tool halves 5 and 6. By means of the interchangeable inserts 59A and 69A, the cover 1 or its receiving area 2 is designed with little effort and adapted to the shape of a decorative element 10 to be connected thereto, which differs in its shape, height and weight from a decorative element 10 which is shown in more detail by way of example in Fig. 5 and in Fig. 8.

[0054] As is known, the covers 1 of airbag modules are each designed with tear lines 17 or so-called split lines or tear edges, shown in more detail in Fig. 2, for example, along which the cover 1 releases an opening when the airbag module is triggered, through which an explosively deploying airbag emerges and dampens an impact of a passenger.

[0055] Using the injection molding tool 4 shown in Fig. 9, the tear line 17 is produced in the cover 1 via the nozzle-side tool half 6. In this case, the tear line 17 may have the course shown in Fig. 10. The tear line 17 of the cover 1 according to Fig. 10 surrounds the receiving area 2 with an arcuate section 17A extending above the receiving area 2, to which clamp-like sections 17B and 17C of the tear line 17 are connected on the outside.

[0056] Fig. 11 shows a representation of the injection molding tool 4 corresponding to Fig. 9, into which further interchangeable inserts 511A and 611A are inserted in order to be able to produce a receiving area 2 shown schematically in Fig. 12, which is essentially quadrangular. The tear line 17 is again produced in the rear side 12 of the cover 1 by the nozzle-side tool half 6 during the manufacture of the cover 1. Fig. 13 shows a representation corresponding to Fig. 12 with a further possible embodiment of the receiving area 2 of the cover 1, which can be produced with low tool costs by means of further interchangeable inserts 513A, 613A that can be inserted into the tool halves 5 and 6 and is in turn adapted to a further decorative element 10.

[0057] It is also possible to connect both single-piece decorative elements or decorative elements consisting of several individual parts to a cover 1. It can be provided that the latter multi-piece decorative elements only receive their final appearance through the form fit with the cover 1.

[0058] In addition, Fig. 14 shows a representation of the injection molding tool 4 corresponding to Fig. 9, into which further interchangeable inserts 514A and 614A are inserted on the nozzle side and ejector side. Using the further interchangeable inserts 514A and 614A, the cover 1 is produced with an outer circular shape of the receiving area 2 shown schematically in Fig. 15 and with a course of the tear line 17 also shown in Fig. 15. The clamp-like sections 17B and 17C of the tear line 17 are produced in the cover 1 via the ejector-side tool half 6. In contrast, the arc-shaped course 17A of the tear line 17 is produced within the receiving area 2 via the ejector-side interchangeable insert 614A. This reduces the visibility of the tear line 17, which improves the overall visual impression of a vehicle.

[0059] Fig. 16 shows a representation of the injection molding tool 4 corresponding to Fig. 14 with further interchangeable inserts 516A and 616A, via which the cover 1 with a receiving area 2 shown schematically in Fig. 17 can be produced. The arc-shaped course 17A of the cover 1 according to Fig. 15 has a substantially triangular course in the cover 1 according to Fig. 17, which is adapted to the rectangular peripheral area of ​​the receiving area 2. The triangular course 17A of the tear line 17 of the cover 1 according to Fig. 17 is in turn created via the ejector-side interchangeable insert 616A in the cover 1 during the plastic injection molding process. In contrast, the clamp-like sections 17B, 17C of the tear line 17 of the cover 1 according to Fig. 17 are formed via the ejector-side tool half 6.

[0060] A representation of a further embodiment of the cover 1 corresponding to Fig. 15 is shown in Fig. 18, in which the tear line 17 comprises an upper section 17D and a lower section 17E. The upper section 17D and the lower section 17E each have at least approximately a U-shaped profile. Between the two U-shaped sections 17D and 17E of the tear line 17, an arcuate profile 17A of the tear line 17 extends, connecting the two U-shaped sections 17D and 17E of the tear line 17 and laterally encompassing the circular receiving area 2.

[0061] Fig. 19 shows a detailed view of another embodiment of a decorative element 10 that can be illuminated or lit. For this purpose, the decorative element 10 comprises an LED 18 that is connected to a light guide 20 arranged on a rear side 19 of the decorative element 10 and shown in more detail in Fig. 20. The light guide 20 is circumferentially surrounded by a carrier 21 of the decorative element 10 according to Fig. 19 and is firmly connected to the latter. A decorative element 22 is attached to the front side of the carrier 21 and is surrounded by a diffuser 23, shown in more detail in Fig. 21, and is attached to the front side of the carrier 21. The diffuser 23 is formed with a PC film.

[0062] As can be seen from Fig. 22, which shows a longitudinal sectional view of the decorative element 10 according to Figs. 19 to 21, the carrier 21 comprises bores 24 for receiving plug-in elements of the decorative element 22 and so-called welding pins 25, via which the decorative element 10 can be firmly connected to the cover 1.

[0063] List of reference symbols

[0064] cover

[0065] Recording area

[0066] Front of the cover

[0067] Injection molding tool nozzle-side tool half of the injection molding toolA Interchangeable insert ejector-side tool half of the injection molding toolA Interchangeable insert

[0068] Opening the cover

[0069] Topology of the recording area

[0070] Web of the receiving area 0 decorative element 1 plug-in elements of the decorative element 1A hot-stitched plug-in element 2 back of the cover 3 free ends of the plug-in elements 3A free end of the hot-stitched plug-in element 4 opening of the receiving area 5 decorative top 6 support element 7 tear line 7A curved course of the tear line 7B clamp-like section of the tear line 7C clamp-like section of the tear line 8 LED 9 back of the decorative element 0 light guide 1 support 2 decorative element 3 diffuser 4 bore 5 welding pins 9A interchangeable insert 9A interchangeable insert

[0071] 511 A interchangeable insert

[0072] 514A interchangeable insert

[0073] 516A interchangeable insert

[0074] 611 A interchangeable insert

[0075] 614A interchangeable insert

[0076] 616A interchangeable insert

[0077] K Circle

[0078] R radial direction

[0079] U circumferential direction

[0080] Z vertical direction

Claims

Patent claims 1 . Method for producing covers (1) of airbag modules, wherein the covers (1) each have a receiving area (2) for at least one decorative element (10; 22) visible to a passenger in the assembled state of a cover, wherein the covers (1) are each manufactured between a first nozzle-side tool half (5) and a second ejector-side tool half (6) of an injection molding tool (4), characterized in that the receiving areas (2) of covers (1) of a first series are formed by at least one interchangeable insert (5A or 6A) or by interchangeable inserts (5A, 6A), which is or are respectively inserted into the first tool half (5) and / or into the second tool half (6), and the receiving areas (2) of covers (1) of at least a second series are each formed by replacing the interchangeable inserts (5A, 6A) with at least one further interchangeable insert (59A, 69A; 511A, 611A; 514A, 614A;516A, 616A) or by means of further interchangeable inserts (59A, 69A; 511A, 611A; 514A, 614A; 516A, 616A) to suit differently designed decorative elements (10; 22) to be inserted into the receiving areas (2).

2. Method according to claim 1, characterized in that the receiving areas (2) of the covers (1) are each arranged within tear lines (17) which are produced by the tool halves (5, 6) and / or by the interchangeable inserts (516A, 616A) in the covers (1) and along which the covers (1) each tear open when the airbag module is triggered and release an opening for an airbag bag.

3. Method according to claim 1 or 2, characterized in that the covers (1) in the receiving areas (2) are each designed with at least one opening (7) into which a plug-in element (11) of the decorative element (10) can be inserted for firmly connecting a decorative element (10) to a cover (1), which plug-in element projects beyond a rear side (19) of the decorative element (10), which in the mounted state of the decorative element Element (10) faces a front side (3) of the receiving area (2) of the cover (1).

4. Method according to A, characterized in that the front sides (3) of the receiving areas (2) of the covers (1) are formed with a topology (8) or with a cambering, by means of which the decorative element (10) is supported on the rear and deformation of the element (10) is prevented.

5. Method according to one of the preceding claims, characterized in that at least the covers (1) of the first series are each formed with at least one connection area for decorative elements (22) which can be illuminated at least in some areas, wherein the illuminable decorative element (22) can be connected to an electrical on-board and control system of a vehicle through the connection area.

6. Method according to one of the preceding claims, characterized in that at least the plug-in elements (11) of the decorative elements (10) are made of plastic, which plug-in elements each pass through the openings (7) of the receiving areas (2) of the covers (1) and are hot-stitched on the rear sides (12) of the covers (1) in order to firmly connect the decorative elements (10) to the covers (1) or are welded to the covers (1) by means of ultrasonic welding.

7. Method according to one of the preceding claims, characterized in that at least the plug-in elements (11) of the decorative elements (10) are made of metal and each pass through the openings (7) of the receiving areas (2) of the covers, wherein free ends (13) of the plug-in elements (11) on the rear sides (12) of the covers (1) are each bent over or riveted to the covers (1) to firmly connect the decorative elements (10) to the covers (1).

8. Method according to one of the preceding claims, characterized in that at least the front sides (3) of the covers are each covered with a covering layer of artificial or natural leather.

9. Method according to one of the preceding claims, characterized in that the covers (1) are designed with graining or design edges at least in the region of their front sides (3).

10. Method according to one of the preceding claims, characterized in that the covers (1) in the receiving areas (2) are each designed with a component weight which is adapted to the component weight of the decorative element (10) to be fastened thereto in such a way that the sum of the component weights of the covers (1) of the series and of the different decorative elements (10) connected thereto is in each case at least approximately the same.

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