Gasbag module for a motor vehicle steering wheel as well as vehicle steering wheel

Abstract

Gasbag module for a motor vehicle steering wheel (10), comprising a gas generator (20) and a gasbag (22) folded into a package, characterized in that the gasbag (22) is arranged in the gasbag module (18) in such a way that it can be connected to the steering wheel (10) in a vibration-isolated manner, while the gas generator (20) has a fastening unit (24) via which it can be rigidly coupled to the steering wheel (10).

Description

The invention relates to a gas bag module for a motor vehicle steering wheel, comprising a gas generator and a gas bag folded into a package. The invention further relates to a vehicle steering wheel. A well-known problem with motor vehicle steering wheels is unwanted vibrations that are perceived as disturbing by the driver, occurring at least in certain speed ranges and being due, not least, to its rigid coupling with the steering column. To avoid such steering wheel vibrations, it has been suggested, among other things, to attach additional masses directly to the steering wheel itself, the effect of which shifts the natural resonance of the steering wheel (including the accelerator pedal module) into frequency ranges that are considered uncritical in motor vehicles. Furthermore, so-called vibration dampers, i.e., spring-mass systems, are used, which can have various designs. In particular, the gas generator of a gasbag module arranged in the steering wheel is used as a counter-oscillating damper mass. Finally, DE 199 13 120 A1 discloses a system in which the entire gasbag module is used as a vibration damper. In this way, the vibrating mass is increased without the use of a separate additional weight. The object of the invention is to provide a gasbag module for a motor vehicle steering wheel or a vehicle steering wheel in which unwanted steering wheel vibrations are effectively prevented or dampened without the use of additional weights. According to the invention, in a gasbag module of the type mentioned above, the gasbag is arranged within the gasbag module in such a way that it can be connected to the steering wheel in a vibration-isolated manner, while the gas generator has a mounting unit by which it can be rigidly coupled to the steering wheel. In the embodiment according to the invention, only the gasbag can vibrate relative to the steering wheel, but not the gas generator, which is rigidly coupled to the steering wheel, thus simplifying its mounting. Particularly when using a small and therefore lightweight gas generator, as is increasingly common in modern driver gasbag modules, the embodiment according to the invention also offers the advantage of increased vibration-isolated mass without the use of additional components. This allows unwanted steering wheel vibrations to be effectively suppressed or eliminated. It should be noted that such a gasbag module typically has a module housing that is rigidly connected to the steering wheel. The gas generator is, in turn, rigidly connected to this gasbag module housing; the gasbag is held within the gasbag module housing in a vibration-isolated manner. A structurally simple design results from the fact that the gas bag can preferably be connected to the steering wheel via at least one bracket in a vibration-isolated manner. The mounting can include at least one retaining element for vibration decoupling. This serves to connect the accelerator pedal to the steering wheel in a vibration-decoupled manner. Preferably, the at least one retaining element is designed as an elastic element; in particular, it is a spring or an elastomer. The connection of the accelerator pedal to the steering wheel (with simultaneous vibration decoupling) can be achieved exclusively via such an elastic element, for example, an elastomer vulcanized to the mounting. Alternatively, an additional locking mechanism in the form of a locking hook or a screw can supplement the elastic element. According to a preferred embodiment, at least one mounting bracket is arranged directly on the gasbag assembly. This allows it to be attached directly in a vibration-isolated manner. In a further development of the invention, the bracket comprises a bearing element on which the airbag is mounted and with which the airbag forms a pre-assembled unit that can be attached to the steering wheel in a vibration-isolated manner. Such a bearing element facilitates the mounting of the airbag in the airbag module or on the steering wheel. In particular, at least one retaining element then engages the bearing part, which also facilitates the attachment of the gas bag. In one embodiment of the invention, the bearing element is a diffuser cage surrounding the gas generator, on which the gas bag is mounted. While the gas generator itself is rigidly coupled to the steering wheel, the diffuser cage, including the gas bag, is vibration-isolated from the steering wheel. Alternatively or additionally, the bearing part can also be a retaining ring. Preferably, the at least one retaining element is coupled to the diffuser cage, in particular wherein the gas bag has an inlet nozzle that is clamped between the diffuser cage and a retaining ring. In this case, the retaining element can engage the diffuser cage or the retaining ring, depending on where, for example, a fastening part is attached and whether the diffuser flange or the retaining ring is located inside or outside the gas bag. Preferably, several mounting elements are provided that project from the rear and / or side of the rest of the airbag module in order to be connected to an end or side wall of a steering wheel hub. This offers various possibilities for vibration-isolated mounting of the airbag assembly to the steering wheel. According to a preferred embodiment, the gas bag is designed as a hot-pressed, folded package in the installed state. As such, the gas bag package is inherently rigid in the uninflated state. Alternatively, a gas bag package is also conceivable, which is wrapped in a kind of foil or with foil tape to secure the package. In a further development of the invention, a cover cap is provided which is rigidly connected to the steering wheel, in particular spaced apart and vibration-isolated from the gas bag, or which forms a pre-assembled unit with the gas bag. In the latter case, the cover cap is placed over the gas bag or the gas bag assembly, but is not attached to the gas generator, which, unlike the gas bag, is not vibration-isolated from the steering wheel. Preferably, the gas bag and / or the pre-assembled unit acts as a vibration damper. This means that the natural frequency of the gas bag, the gas bag assembly, or the pre-assembled gas bag unit is tuned to the natural frequency of the rest of the steering wheel and its coupled components (including the gas generator) in such a way that the gas bag or gas bag unit eliminates unwanted vibrations. It is also conceivable that the vibration decoupling of the gas bag or gas bag unit shifts the natural frequencies of the steering wheel into non-critical ranges. The aforementioned problem is also solved by a vehicle steering wheel comprising a steering wheel hub, a steering wheel rim connected to the steering wheel hub via at least one spoke, and the gas bag module according to the invention, wherein the gas generator is rigidly coupled to the steering wheel hub and at least the gas bag is vibration-isolated from the steering wheel hub. Of course, a pre-assembled unit consisting of the gas bag and its mounting can also be vibration-isolated from the steering wheel hub. Furthermore, all advantages and further developments mentioned with regard to the gas bag module also apply to the vehicle steering wheel according to the invention. Further features and advantages of the invention will become apparent from the following description of several preferred embodiments with reference to the accompanying drawings. These show: Fig. 1 a schematic sectional view of a vehicle steering wheel with a gasbag module according to a first embodiment of the invention; Fig. 2 a schematic sectional view of a vehicle steering wheel with a gasbag module according to a second embodiment of the invention; and Fig. 3 a schematic sectional view of a vehicle steering wheel with a gasbag module according to a third embodiment of the invention. Fig. 1 shows a motor vehicle steering wheel 10, which has a cup-shaped steering wheel hub 12 and a steering wheel rim 16 connected to the steering wheel hub 12 via several spokes 14. Inside the cup-shaped steering wheel hub 12 is a gas bag module 18, which includes a gas generator 20 and a gas bag 22 folded into a package. The gas generator 20 is rigidly coupled to the steering wheel 10, more precisely to the steering wheel hub 12, via a fastening unit 24. In contrast, the gasbag 22, which in its installed state is designed as a hot-pressed, self-stiffening package, is vibrationally decoupled from the steering wheel 10 or the steering wheel hub 12 via a bracket 26. The bracket 26, located directly on the gas bag assembly, comprises a bearing element in the form of a diffuser cage 28, which surrounds the gas generator 20 and on which the gas bag 22 is mounted. The gas bag 22 and the diffuser cage 28 form a pre-assembled unit. A receiving pot can be used to house the gas bag 22. Furthermore, several retaining elements 30 are provided, designed as elastic elements, specifically springs, which engage the diffuser cage 28. These project from the rear of the remaining airbag module 18 and are connected to an end wall 32 of the steering wheel hub 12. In addition, further retaining elements 34 project laterally from the airbag module 18, which, for example, engage directly at the receiving cup of the airbag 22 and are connected to a side wall 36 of the steering wheel hub 12. The pre-assembled unit consisting of the airbag 22 and the diffuser cage 28 is vibrationally decoupled from the steering wheel hub 12 via the retaining elements 30 and 34, and can thus act as a vibration damper. As an alternative to the spring elements shown in the figure, the use of a sleeve-shaped elastomer or several elastomers surrounding the gas generator 26 is also conceivable, or the vibration-decoupled fastening of the gas bag package via an elastic element plus securing in the form of a locking hook or a screw. Additionally, a retaining ring (not shown in Fig. 1) can be provided, in which case an inlet nozzle 38 of the gas bag 22 is clamped between the diffuser cage 28 and the retaining ring. In this case, the retaining elements 30 can of course also engage the retaining ring. Fig. 2 shows a vehicle steering wheel 10 according to a second embodiment of the invention, the differences from the first embodiment of which will be discussed below. The vehicle steering wheel 10 with the airbag module 18 differs from the previously described one in that the unit consisting of the airbag 22 and the diffuser cage 28 is vibrationally decoupled from the steering wheel hub 12 exclusively via the retaining elements 30 projecting from the rear of the airbag module 18. Furthermore, the airbag module 18 has a cover cap 40 that is placed over the folded airbag 22 or the receiving cup and forms a pre-assembled unit with it. The cover cap 40 can therefore oscillate with the airbag 22 relative to the steering wheel 10. Fig. 3 shows a further embodiment of the vehicle steering wheel 10 with airbag module 18, which differs from that shown in Fig. 2 only in that a cover cap 40 is provided here, which is rigidly connected to the steering wheel 10. The cover cap 40 is thus spaced apart and vibration-isolated from the airbag 22 or the pre-assembled unit consisting of the airbag 22 and the diffuser cage 28. Naturally, each of the illustrated configurations of the gasbag module 18 can have any type of cover cap 40. To operate the horn, the cover cap 40 can be moved (see Fig. 3) or switches can be provided on the cover cap 40. In the embodiment according to Fig. 1 and Fig. 2, for example the gas bag 22, which is covered at the front, can be pressed towards the bottom of the steering wheel hub 12.

Claims

Gasbag module for a motor vehicle steering wheel (10), comprising a gas generator (20) and a gasbag (22) folded into a package, characterized in that the gasbag (22) is arranged in the gasbag module (18) in such a way that it can be connected to the steering wheel (10) in a vibration-isolated manner, while the gas generator (20) has a fastening unit (24) via which it can be rigidly coupled to the steering wheel (10). Gasbag module according to claim 1, characterized in that the gasbag (22) can be connected to the steering wheel (10) via at least one support (26) in a vibration-decoupled manner. Gasbag module according to claim 2, characterized in that the holder (26) has at least one retaining element (30, 34) for vibration decoupling. Gasbag module according to claim 3, characterized in that the at least one retaining element (30, 34) is designed as an elastic element. Gasbag module according to one of claims 2 to 4, characterized in that the at least one support (26) is arranged directly on the gasbag package. Gasbag module according to one of claims 2 to 5, characterized in that the holder (26) comprises a bearing part on which the gasbag (22) is mounted and with which the gasbag (22) forms a pre-assembled unit which can be attached to the steering wheel (10) in a vibration-decoupled manner. Gas bag module according to claim 6, characterized in that the at least one retaining element (30, 34) engages the bearing part. Gasbag module according to claim 6 or 7, characterized in that the bearing part is a diffuser cage (28) surrounding the gas generator (20), on which the gasbag (22) is mounted. Gas bag module according to claim 8, characterized in that the at least one retaining element (30, 34) is coupled to the diffuser cage (28), in particular wherein the gas bag (22) has an inlet mouth (38) which is clamped between the diffuser cage (28) and a retaining ring. Gasbag module according to one of the preceding claims, characterized in that retaining elements (30, 34) extend from the rear and / or side of the rest of the gasbag module (18) in order to be connected to an end wall or a side wall (32, 36) of a steering wheel hub (12). Gas bag module according to one of the preceding claims, characterized in that the gas bag (22) is designed as a hot-pressed, folded package in the installed state. Gasbag module according to one of the preceding claims, characterized in that a cover cap (40) is provided which is rigidly connected to the steering wheel (10), in particular spaced apart and vibration-decoupled from the gasbag (22), or which forms a pre-assembled unit with the gasbag (22). Gas bag module according to one of the preceding claims, characterized in that the gas bag (22) and / or the pre-assembled unit is a vibration damper. A vehicle steering wheel comprising a steering wheel hub (12), a steering wheel rim (16) connected to the steering wheel hub (12) via at least one spoke (14) and the gas bag module (18) according to one of the preceding claims, wherein the gas generator (20) is rigidly coupled to the steering wheel hub (12) and at least the gas bag (22) is vibration-decoupled from the steering wheel hub (12).

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