WO2011054449A1

WO2011054449A1 - Air bag module

Info

Publication number: WO2011054449A1
Application number: PCT/EP2010/006453
Authority: WO
Inventors: Raimund Nebel; Martin Haas
Original assignee: Autoliv Development Ab
Priority date: 2009-10-27
Filing date: 2010-10-22
Publication date: 2011-05-12
Also published as: DE102009050893A1

Abstract

The invention relates to an air bag module, comprising a housing having a housing bottom, in which housing an air bag is accommodated, and an installation plate having an upper face and a lower face for arrangement on a vehicle part. The housing bottom lies on the upper face of the installation plate. The air bag module further comprises at least one retaining part, in particular a bolt (30, 30'), which is rigidly connected to the housing bottom and which has a lower wall, an opening in the installation plate, through which the retaining part extends, and a rod-shaped spring element, which is retained on the lower face of the installation plate and which is supported on contact sections of the lower face of the installation plate and which lies against the lower wall and which has at least two sections (52a, 52b). In order to reliably prevent rattling noises during driving without having to reduce the tolerances, the angle between the lower wall and the contact section changes in the radial direction of the lower wall in such a way that the angle has a smaller value in an outer area of the lower wall than in an inner area.

Description

Airbag module

description

Technical field of the invention

The invention relates to a gas bag module according to the preamble of claim 1.

For many years, almost every steering wheel of a motor vehicle has an airbag module, which in most cases is arranged in a recess in the hub region of the steering wheel body. There are numerous ways known how the housing of the gas bag module can be arranged directly or indirectly on the steering wheel body. A commonly used gas bag module is structured as follows:

PRIOR ART The gas bag module has a housing and a mounting plate. This mounting plate is either rigid or arranged by means of horn springs on the steering wheel body and the housing is rigidly connected to the mounting plate. In this case, the housing bottom rests on an upper side of the mounting plate. Vo housing bottom extends at least one holding part, for example in the form of a bolt, through an opening in the mounting plate. This holding part has a bottom wall. If the holding part, as usually, designed as a bolt, so extends into the lateral surface of the bolt, a groove having an upper and the lower wall, wherein at least the lower wall extends against the horizontal surface inclined so that it is pointing obliquely upward.

On the underside of the mounting plate, a rod-shaped spring element is held, which sections of the above-mentioned lower wall and at less

CONFIRMATION COPY Stens a contact portion of the underside of the mounting plate and thus holds the housing to the mounting plate. In most cases, at least two such bolts are present and the rod-shaped spring elements are sections of a U or Ω-shaped spring wire. However, it can also be provided two individual spring rods. The lower walls of the holding parts generally point inwards, ie toward the center of the gas bag module, and the spring elements are biased outwards. However, the reverse, ie outwardly facing lower walls and inwardly biased spring elements, is also possible. The assembly is done as follows.

First, the mounting plate is mounted in the recess of the steering wheel body. In this case, it can either be rigidly connected to the steering wheel body or by means of horn springs with this. Subsequently, the housing is snapped onto the mounting plate, wherein each rod-shaped spring element is first pivoted by the openings piercing through the holding part inwardly and then locks on the lower wall. A possible dismantling takes place in that each rod-shaped spring element is unlocked by means of a tool from its respective lower wall by pivoting inwards. The advantages of such a gas bag module are its cost-effective manufacturability and its ease of assembly and disassembly. A disadvantage of such a gas bag module is that, unless extremely narrow tolerances are maintained, rattling noises during driving can occur. The compliance with extremely small tolerances, however, increases the production costs significantly.

Subject of the invention

Therefore, the present invention has the object to develop a generic gas bag module to the effect that rattling noises are reliably prevented while driving, without the tolerances would have to be reduced and without compromising the reliability of the airbag module would have to be made. This object is achieved by an airbag module having the features of claim 1.

The geometry and dimensions of many components can be varied only to a very limited extent due to structural conditions and / or specifications of the vehicle manufacturer. These include, for example, the diameter of the bolts, which are usually used as holding parts and which can not be chosen arbitrarily large. This would also be undesirable due to a corresponding increase in modulus weight. Furthermore, the inclination of the lower wall can not be chosen arbitrarily steep, otherwise it is not ensured that the housing is held securely on ignition plate of the gas generator. These specifications result in the tolerance problem mentioned above. This is to be explained by the following extreme example: If the lower wall runs parallel to the contact section of the mounting plate, then the tolerance would be exactly zero: If the gap between lower wall and contact section of the mounting plate were only slightly too small, the rod-shaped spring element could not enter the gap between penetrate lower wall and abutment section. If the distance were only slightly too large, the Z-position of the bolt (and thus of the housing) would be undefined, which would inevitably lead to rattling noises. The steeper the lower wall is placed with horizontally extending contact section, the more the tolerance increases, however, the steepness is limited for the reasons mentioned above.

In other words: To achieve a high tolerance, the angle should see between the bottom wall and the associated contact portion of the underside of the mounting plate as steep as possible to ensure a secure holding the housing to the mounting plate at ignition of the gas generator, the angle be as flat as possible. According to the invention, therefore, the lower wall and / or the abutment portion of the underside of the retaining plate are formed so that at least two angles arise between these components, namely a shallow angle in an outer portion and a steeper angle in an inner portion. The different angles can be assigned exclusively to the holding part, exclusively the contact section or both components. The angular profiles can be divided into discrete sections or run continuously.

Preferred embodiments of the invention will become apparent from the subclaims and from the now explained in more detail with reference to the figures embodiments. Hereby show:

Brief description of the drawings

1 shows a gas bag housing in a first sectional view,

FIG. 2 shows a part of a steering wheel body with mounting plate accommodated in the hub region in a first sectional view,

Figure 3 shows the two components of Figures 1 and 2 in the assembled state in a second sectional view, wherein the section of this second sectional view is parallel to the sections of Figures 1 and 2

FIG. 3a the detail D1 from FIG. 3,

Figure 4 is a bottom view of the mounting plate from direction R1 in

FIG. 3,

FIG. 5 shows a second embodiment of the invention in a representation corresponding to FIG. 3,

FIG. 5a the detail D2 from FIG. 5,

FIG. 6 shows the embodiment shown in FIG. 5 in a representation corresponding to FIG. 4 and FIG

Figure 7 shows a second embodiment of the second embodiment in a representation corresponding to Figure 5a.

Description of preferred embodiments

In the embodiments shown, the holding parts are designed as a bolt, which is usually preferable, but not mandatory. In this case, the lower one Wall a lower wall of a groove which extends into the lateral surface of the bolt.

The following definitions apply to the following: The Z-direction or axial direction is the direction of the axis of the steering column 14, which in the embodiment shown is also the direction of the axis of the cylindrical gas generator 26. The bolts 30, 30 'on soft will be discussed in more detail later, are sections of cylinders, in the lateral surface 30a, 30a' grooves 32, 32 'are milled. The axes of the bolt underlying rotary parts also extend in the Z or axial direction. Perpendicular to this axial direction Z is the normal plane E. This is normal to the plane of the axial direction Z and thus also normal to the lateral surface of the cylindrical portions of the bolt. In FIGS. 1, 2, 3, 3a, 5 and 5a, the normal plane E is perpendicular to the plane of the drawing; in FIGS. 4 and 6, the normal plane E is parallel to the plane of the drawing. first embodiment

As can be seen with reference to Figures 1, 2, 3 and 4, the gas bag module consists of a housing 22 and a mounting plate 40. Figures 1 and 2 show the not yet mounted state, Figures 3 and 4, the mounted state , The illustration in FIGS. 1 and 2 correspond to the sectional plane A-A in FIG. 4, FIG. 3 is a section along the plane B-B in FIG. 4.

The mounting plate 40 is received in a recess 12 in the hub region of the steering wheel body 10 and connected to the steering wheel body 10. This connection with the steering wheel body 10 may be rigid or effected by means of springs acting in the axial direction. Since it does not depend on the connection between the mounting plate 40 and the steering wheel body 10 in the present case, the type of attachment is not shown.

The housing 22 has a housing bottom 24, through which the gas generator 26 extends into the interior of the housing 22 and into the interior of the gas bag 28 folded into the housing 22. From the housing bottom 24 extend Bolt 30, 30 ', in the embodiment shown two pieces, which are rigidly connected to the housing bottom 24. The bolts 30, 30 'extend in the axial or Z-direction. In the lateral surface 30a, 30a 'of each bolt 30, 30' is a groove 32, 32 'with an upper wall 34, 34' and a lower wall 36, 36 'milled. The grooves 32, 32 'in this case have inwardly, ie to the center of the housing bottom 24th

The mounting plate 40 has a central opening 56 for the gas generator 26 and for each bolt 30, 30 'an opening 54, 54'. Through these breakthroughs 54, 54 ', the bolts 30, 30' extend in the mounted state (FIGS. 3 and 4) such that in each case a part of the grooves 32, 32 'is located below the underside 44 of the mounting plate 40. On the bottom 44 of the mounting plate 40 is a U- or Ω-shaped spring wire 52 is held, including serve on the bottom 44 of the mounting plate 40 arranged bracket 50a to 50d. Left and right sections 52a, 52b of the spring wire 52 form rod-shaped spring elements and are biased so that they press outward, ie in the radial directions RA1 and RA2. In addition to each aperture 54, 54 'is at least one contact portion of the underside of the mounting plate on which abuts the respective portion of the spring wire. In the illustrated embodiment, each aperture two contact portions 45a, 45b; 45a ', 45b' assigned. The abutment sections may or may not be offset from the surrounding areas of the underside of the mounting plate. In the first embodiment, the abutment portions extend parallel to the normal plane E. Further, right and left portions 52a, 52b of the spring wire 52 abut each other on the lower wall 36a, 36a 'of their groove 32a, 32b, and press due to their bias and Slanting the lower walls 36, 36 ', the bolts 30, 30' down, whereby the housing bottom 24 is pressed onto the top 42 of the mounting plate 40. In the exemplary embodiment shown, the housing bottom 24 is pressed onto the upper side 42 of the mounting plate 40 essentially over its entire surface. Depending on the configuration of the housing base 24 and the mounting plate 40, this can only be done in sections. The bolts 30, 30 'and the regions of the openings 54, 54' and the adjacent abutment portions 45a, 45b; 45a ', 45b' are symmetrical to each other; The following explanations regarding the shape and function of the groove 32 and the associated abutment sections 45a, 45b of the left side also apply analogously to the groove 32 'with associated abutment sections 45a', 45b 'on the right side.

As can be seen in particular with reference to FIG. 3a, the lower wall 36 of the groove 32 has two sections, namely an outer section 36a and an inner section 36b, the outer section 36a having the normal plane E a first angle α and the inner section 36b with the normal planes includes a second section ß. Here, the first angle α is smaller than the second angle β, if the following definition applies: Counted is from the bottom wall of the groove in mathematically positive direction (ie to the left). In other words, the inner portion is flatter against the horizontal than the outer portion. Preferred ranges for the two angles are: 3 ° <α <15 ° and 20 ° <β <40 °.

In the first embodiment, as already mentioned, the abutment sections 45a, 45b of the lower side 44 of the mounting plate 40 are parallel to the normal plane E, so that the just-defined angular relationship also applies between the lower wall 36 and the abutment sections 45a, 45b, as in FIG. 3a is also shown. Due to the steeper angle of the inner portion 36b, the tolerance range in which the respective portion of the spring wire 52 bears against both the lower wall 36 and the abutment portions 45a, 45b is opposite to a lower wall 36 which continuously adjusts the angle outer portion 36a would have increased. The shallow angle of the outer portion 36a ensures that even if the gas generator 26 is ignited and also the housing 22 a large force in the Z direction is exerted, a snapping of the spring wire 52 is prevented from the groove 32. The improvement according to the invention is therefore achieved in that the angle between the lower wall 36 of the groove 32 and the associated abutment sections 45a, 45b is not constant. second embodiment

In the second embodiment as well, the symmetry relationship described above applies between the left and right sides, so that the left side is referred to:

In the second embodiment, shown in Figures 5, 5a and 6, the desired effect is not achieved by different angles of the bottom wall 36, but by different angles of the associated abutment portions 45a, 45b, including the bottom 44 of the mounting plate 40 ramps 46a, 46b; have, so that the abutment sections each have two subsections, which are designated in Figure 5a with 48a and 48b. These ramps rise outward and begin - in the projection views of FIGS. 5, 5a - "in" the groove 32, so that in the radial direction a distance a between the outer beginning of the groove and the beginning of the ramps 46a, 46b and, with respect to the radial extent of the groove, there are two different angles between the contact section and the lower wall 36 of the groove.These two angles are also denoted by .alpha. and .beta .. The above definitions regarding the orientation of the angles are retained same as described above, namely that the tolerance in the Z-direction is increased and yet in an edge region the angle between the lower wall and contact section is flat, which prevents inadvertent snapping of the spring wire upon ignition of the gas generator and corresponding introduction of force. 3 ° <α <15 ° and 20 ° <β <40 °.

FIG. 7 shows a second embodiment of the second embodiment. Here, instead of a ramp, a nose 60 is provided on the underside 44 of the mounting plate 40. This lug 60 is on the opposite side as the ramps 46a, 46b of the previously described embodiment and is oriented opposite. Again, there are different angles between the bottom wall 36 of the groove and the associated bearing portion, which also here has two subsections 48a, 48b. The first angle α can even be negative here. The lower wall of the groove can be relatively steep throughout. hen, as an unintentional snapping the portion 52 a of the spring wire 52 is prevented from the groove 32 through the nose 60.

Such a nose can in principle also be arranged on the lower wall of the groove, but would have the disadvantage of a less simple mounting and demountability of the housing on the mounting plate.

Mixed forms between the two embodiments just described are possible. Furthermore, it is possible that the angles of the contact section and / or of the lower wall 36 change continuously, resulting in continuous surfaces.

LIST OF REFERENCE NUMBERS

10 steering wheel body

12 recess

14 steering column

20 airbag module

22 housing

24 caseback

26 gas generator

28 airbag

30, 30 'bolts

30a, 30a 'lateral surface

32, 32 'groove

34 upper wall

36 lower wall

36a outer section

36b inner section

40 mounting plate

42 top

44 bottom

45a, 45a '

45b, 45b 'abutment section

46a, 46b

46a ', 46b' ramp

48a, 48b subsection

50a-d strap

52 spring wire

52a left section

52b right section

52c middle cut

54, 54 'opening

56 middle opening

60 nose

Claims

claims

1. Airbag module having a housing base (24) having a housing (22) in which a gas bag (28) is received, one of a top side (42) and a bottom (44) having mounting plate (40)

Arrangement on a vehicle part, wherein the housing bottom (24) rests on the upper side (42) of the mounting plate (40), at least one holding part, rigidly connected to the housing bottom (24), having a lower wall (36), an opening (54, 54 ') in the mounting plate (40) through which the holding part extends, and one at the bottom (44) of

Mounting plate (40) held on abutment portions (45a, 45b) of the underside (44) of the mounting plate (40) and supporting the lower wall (36) adjacent rod-shaped spring element (52),

characterized in that the angle between lower wall (36) 5 and abutment portion (45a, 45b) in the radial direction of the lower wall (36) changes such that it has a smaller value in an outer area of the lower wall (36) than in an inner area.

2. Airbag module according to claim 1, characterized in that the holding part is a part of a lateral surface (30a, 30a ') exhibiting bolt (30, 30'), in whose lateral surface (30a, 30a ') has a groove (32, 32 ') with an upper wall (34) and the lower wall (36),

3. Airbag module according to claim 1 or claim 2, characterized marked 5 net, that the angle at least two discrete values (a, ß) occupies.

4. The gas bag module according to any one of the preceding claims, characterized in that the lower wall (36) has an outer portion (36 a) and an inner portion (36 b) having different angles of inclination. The gas bag module according to any one of the preceding claims, characterized in that the abutment portion has an outer portion and an inner portion with different inclination angles.

The gas bag module according to one of the preceding claims, characterized in that the rod-shaped spring element is a section of a U-shaped or Ω-shaped spring wire (52).