WO2021018662A1

WO2021018662A1 - Airbag assembly, seat assembly, motor vehicle and inflating unit

Info

Publication number: WO2021018662A1
Application number: PCT/EP2020/070506
Authority: WO
Inventors: Markus Leifheit; Marc Schock
Original assignee: Autoliv Development Ab
Priority date: 2019-07-31
Filing date: 2020-07-21
Publication date: 2021-02-04
Also published as: DE102019120673A1

Abstract

An airbag assembly, especially a side airbag assembly is described. This airbag assembly comprises an airbag and an inflating unit (15) being located inside the airbag at least in sections. The inflating unit (15) comprises an oblong inflator body (20) extending from a first axial end to a second axial end and having a generating surface with outlet openings (22) being provided in an outlet area of the generating surface near the second axial end in a thrust-neutral manner, and a deflector (30) having a covering section covering at least some of the outlet openings (22). The covering section and said outlet area define a free cross-section. The deflector (30) deflects at least the majority of the gas exhausted through outlet openings (22) in a first axial direction towards the first axial end of the inflator body (20). In order to save packing space without limiting the amount of gas deflected by the deflector, the gas streaming out of the outlet openings (22) when the inflator is triggered deforms the covering section at least partially such that the free cross-section is enlarged.

Description

Airbag assembly, seat assembly, motor vehicle and inflating unit

Description

The invention relates to an airbag assembly according to the preamble of claim 1 , to a vehicle seat assembly with such an airbag assembly according to claim 1 1 , to a motor vehicle comprising such a vehicle seat assembly according to claim 12 and to an inflating unit for the use in an airbag assembly according to claim 13.

Many of today’s motor vehicles, particularly passenger cars, are equipped with so called side airbag assemblies whose side airbag protect the pelvis as well as the thorax of a person. Such side airbag assemblies comprise an inflator and a side airbag and are usually located inside the vehicle seat and connected to the frame of this vehicle seat.

In the standard use of the side airbag assembly, this side airbag assembly is located on the outer side of the seat meaning that the airbag of this airbag assembly deploys between the outer structure of the vehicle and the person to be protected in the case of a side collision, but it is also known to provide such a side airbag assembly on the vehicle inner side of the seat meaning that this side airbag deploys between two seats.

The inflating unit of such a side airbag assembly most often comprises an inflator body with an oblong and basically cylindrical shape that in the mounted state extends from a lower first axial end to an upper second axial end. The electrical connector is usually located at the lower end or an ignition cable extends from the lower end. The outlet openings for the gas are most often located in an outlet area of the generating surface near the upper end in a thrust-neutral manner. From generic US 6 231 069 B1 it is known to provide a deflector having a covering section covering at least some of the outlet openings, wherein the covering section and said outlet area define a free cross-section. The deflector deflects at least the majority of the gas exhausted through outlet openings in an axial direction towards the first axial end of the inflator body and thus towards the lower area of the side airbag. This has the advantage that this lower area that is protecting the pelvis of the passenger is inflated more quickly.

Starting from the prior art it is an object of the invention to provide an airbag assembly which gives good and secure protection for a person to be protected even under difficult geometrical conditions.

This task is solved by an airbag assembly with the features of claim 1. A vehicle seat with such an airbag assembly is defined in claim 1 1 , and a car with such a vehicle seat is defined in claim 12. An inflator for the use in such an airbag assembly is defined in claim 13.

Often cars are designed in a way that only a little space for the airbag assembly is provided in the seat. Additionally the seat is often located very close to an adjacent structure (in the case of an outside side airbag assembly the outer structure of the vehicle) and the little space provided for the airbag assembly often leads to the necessity that the electrical connector is located at the lower end of the oblong inflator body and that the outlet openings are provided near the upper end of the oblong inflator body (as described above). It turned out that due to this geometry it can be difficult to design the vehicle such that the lower portion of the airbag protecting the pelvis of the person to be protected inflates sufficiently fast. In the side airbag known from generic US 6 231 069 B1 gas is deflected downwardly, which is an improvement, but often, the space available does not allow a geometry which leads to a sufficiently large free cross-section. According to the invention, the deflector is designed such that gas streaming out of the outlet openings deforms the covering section at least partially such that the free cross-section between the covering section and the generating surface is enlarged. By this measure, the inflating unit can be designed sufficiently slim, but still the gas stream downwards towards the lower area of the side airbag is strong enough to inflate this area quickly.

Usually, the covering section is a sleeve or a section of a sleeve.

In a first preferred embodiment the sleeve comprises at least one flap bending outwardly when gas flows out of the outlet openings. Such a sleeve can be produced very easily because it is only necessary to stamp slits or a breaking lines into the sleeve.

In a first preferred embodiment the sleeve is folded such that it comprises at least one three-layered section in the idle state of the inflating unit. In this case the sleeve, or a section of the sleeve, is expanded when gas flows out of the outlet openings, but keeps a closed generating surface. This can help to generate a reproducible deployment behavior.

Since it is a primary goal of the invention to provide a small inflating unit, it will often be preferred that the free cross-section is basically zero in the idle state of the inflating unit.

In order to reduce weight, it can be preferred that the sleeve is held by at least one stud extending from the inflator body.

Depending on the overall geometry and the desired inflating behavior, the deflector can be designed such that it additionally deflects a part of the gas exhausted through the outlet openings in an axial direction towards the second axial end of the inflator body. As mentioned, the main application of the invention is a side airbag assembly adapted for being mounted to a vehicle seat, wherein the deflector guides at least a part of the gas stream downwards, but of course other applications are possible. The invention will now be described in view of preferred embodiments in view of the figures. The figures show:

Figure 1 an inflator body, Figure 2 the in inflator body of Figure 1 and a deflector mounted to this inflator body such that an inventive inflating unit is formed,

Figure 3 a sectional view taking a long plane A-A in Figure 2, Figure 4 what is shown in Figure 3 with the inflating unit being a part of a side airbag assembly being mounted to the frame of the vehicle seat,

Figure 5 the inflating unit of Figure 2 in a sectional view taking along plane B-B in Figure 2,

Figure 6 the inflating unit shown in Figure 2 after the pyrotechnic load housed in the inflator body has been ignited,

Figure 7 what is shown in Figure 4 in the state shown in Figure 6,

Figure 8 as schematic representation of a side airbag assembly being comprised of the inflating unit shown in Figure 2 and a side airbag,

Figure 9 what is shown in Figure 8 after the inflating unit has being triggered such that the side airbag deploys, Figure 10 a schematic representation of a second embodiment of an inflating unit,

Figure 1 1 a blank for a sleeve of a deflector,

Figure 12 an inflating unit comprising a deflector being made from the sleeve of

Figure 1 1 in a mounted state and a plan view from the side,

Figure 13 a sectional view taken along plane C-C in Figure 12,

Figure 14 what is shown in Figure 12 after ignition of the inflating unit, Figure 15 what is shown in Figure 14 in a representation according to figure 13, Figure 16 a blank for a sleeve of a further embodiment of the inventive inflating unit,

Figure 17 the inflating unit in a representation according to Figure 12, Figure 18 the inflating unit of Figure 17 in a representation according to Figure

13,

Figure 18a what is shown in Figure 18 in an enlarged representation, Figure 19, the inflating unit of figure 17 after ignition of the inflating unit,

Figure 20 what is shown in Figure 19 in a representation according to Figure 18,

Figure 21 a schematic representation of a seat assembly of the prior art, Figure 22 a sectional view taken along plane E-E in Figure 21 , but without the person in the vehicle seat, and additionally a part of the outer vehicle structure,

Figure 23 what is shown in Figure 21 after deployment of the side airbag,

Figure 24 what is shown in Figure 23 in a sectional view taken along plane F-F in Figure 23 in case that the seats are each equipped with two side airbag assemblies, and

Figure 25 what is shown in Figure 22 when a side crash occurred.

In order to better understand the invention, reference is first made to the prior art in view of the Figures 21 to 25. Figure 21 shows a schematic side view onto a vehicle seat assembly being comprised of a vehicle seat 60 and at least one side airbag assembly being located inside the backrest of this seat. This side airbag assembly 5 is comprised of an inflating unit 15 and a side airbag 10 which is shown in its resting, folded state. The inflating unit has an inflator body being attached to the frame 62 of the backrest of the vehicle seat.

Figure 22 shows what is shown in Figure 21 (but without the occupant), and additionally a section of the outer vehicle structure 62, usually a section of the car body. One can see that often there is a little space between the side airbag assembly 5 and this vehicle structure 62.

Figure 23 shows what is shown in Figure 21 after deployment of the side airbag 10 and Figure 24 shows a sectional view taken along plane F-F in Figure 23 in the case that both vehicle seats 60, 60^' are equipped with two side airbag assemblies each having a side airbag 10a, 10; one at the outer side of the vehicle and one at the inner side of the vehicle. At this point it is to be noted that the invention described in detail later, can be applied to both: side airbag assemblies being located on the outer side of the vehicle seat and side airbag assemblies being located on the inner side of the vehicle seat. The reason for this is that the available space can be limited in both cases. The arrow in Figure 24 indicates a typical height at which an external object hits the vehicle in case of an accident.

Figure 25 shows the situation after an external object 64 (for example a car) hits the vehicle structure 62 basically at the height indicated by the arrow in Figure 24. Since the outlet openings 22 are located at the upper end of the inflator body 20 there can occur a problem that gas exhausted through this outlet openings does not reach the lower end of the side airbag 10 quickly enough such that the intruding part of the vehicle structure 26 hinders this lower part from deploying. This would of course lead to a reduced protection. A deflector as shown in generic US 6 231 069 B1 might help to improve the deployment behavior but can often not be used because there is not sufficient space.

In view to Figures 1 to 9 a first embodiment of an inventive inflating unit is described which solves the above described problem. The basic idea is to provide a deflector at the upper end of the inflator body such that a covering section of this deflector covers at least a part of the outlet openings in a way that at least a part of the gas that leaves the inflator body in a radial direction is directed downwards towards the lower end of the side airbag (basically in axial direction). Of course there must be a relatively large free cross-section between the generating surface of the inflator body and the covering section so that sufficient gas can flow into this direction.

If one used a static deflector this would mean that either the overall volume occupied by the inflating unit would be relatively large or that the free cross-section between the generating surface of the inflator body and the deflector would be relatively small. So, according to the invention a deflector is used that is deformable at least in sections, such that the gas streaming out of the outlet openings when the inflator is triggered deforms the covering section at least partially such that the free cross-section is enlarged.

Figure 1 shows the inflator body 20 alone. This inflator body is basically in form of a cylinder that has a generating surface 20a and extends from a first axial end 20b to a second axial end 20c. The outlet openings 22 are arranged in an outlet area of the generating surface 20a near the second axial end 20c in a thrust-neutral manner. An ignition cable extends from the first axial end 20b at least in the mounted state of the inflator body 20 (not shown).

Figure 2 shows the complete inflating unit 15 which additionally comprises a deflector 30 in form of a cap meaning that this deflector 30 has an end wall 32 and a sleeve 34. The end wall 32 is connected to the end wall of the inflator body 20 forming its second axial end 20c. This connection is not shown in detail in the figures.

The lower area of the sleeve 34 covers the outlet openings 22. This lower area of the sleeve 34 is divided into sections (here three sections 34a, 34b and 34c) by means of slits (here three slits 35a, 35b and 35c). Of course, other numbers of sections/ slits could be chosen.

When the pyrotechnic load 26 inside the inflator body is ignited and gas streams out of the inflator body 20 through the outlet openings 22 in radial direction, the gas pressure presses the sections 34a, 34b and 34c to the outside such that the free cross section between the generating surface 20a of the inflator body 20 and the sleeve 34 (which is a part of the deflector) is increased. Since the deflector 30 is closed at its upper end, basically all of the gas streaming out of the outlet openings 22 is directed downwards towards the first axial end 20b of the inflator body 20 as shown in Figure 6. Figure 8 shows an inventive side airbag assembly with the inflating unit 15 just described in a not deployed state; Figure 9 shows what is shown in figure 8 in a deployed state. One can see here that the gas is guided by the deflector and the side airbag 10 basically deploys from its lower area.

Figure 10 shows a second embodiment of the inventive inflating unit 15 in an also schematic sectional view after the pyrotechnic load has been ignited. Here the deflector 30 is also basically in a form of a cap, but its lower end (the end remote from the second axial end 20c of the inflator body 20) is crimped to the inflator body 20. The flaps (there are two flaps 34a, 34b shown in Figure 10) are surrounded by basically U-shaped cut-outs or breaking lines. In this embodiment additionally a hole 33 is provided in the end wall 32 of the deflector 30 such that a part of the gas streams into an upwards direction when the deflector is mounted. Figures 1 1 to 15 show an embodiment which is very easy to manufacture. Here, the deflector 30 only consists of a sleeve being bent from a basically rectangular blank 40 shown in Figure 1 1 . The blank 40 is usually a stamped piece of sheet metal. This blank 40 has a hole 42 and an indention 44. Additionally this blank shows at least two slits 35a, 35b such that at least one flap (section of the sleeve) 34a is defined. When assembling the inflating unit 15, a stud extending from the inflator body 20 near the second axial end 20 of the inflator body is pushed through the hole 42 and then the blank 40 is wrapped around the inflator body until the same stud extends through the indention 44. By this process the sleeve 40 is generated. For example by screwing a nut onto the stud, the sleeve can be fixed to the inflator body 20. As it has already been described, the flap 34a is bent outwards as soon as gas streams out of the outlet openings 22. Of course, more than one flap can be provided with the same technic.

Figures 16 to 20 show a similar embodiment, but here the slits are replaced by bending lines 36. In this embodiment eight bending lines 36a to 36h are provided. When applying this blank to the inflator body, these bending lines are folded such that folds 34d - 34f as shown in Figure 18a are generated. When gas streams out through the outlet openings, the sleeves expands as shown in Figures 19 and 20. If no additional measures are taken, the sleeve expands along its entire length (as shown) such that a part of the gas is deflected towards the second axial end 20c of the inflator body 20.

One sees that by means of a simple to produce deflector, the deployment behavior of a side airbag can be improved without demanding additional packaging space.

List of reference numbers

5 side airbag assembly

10 side airbag

10a outer side airbag

10b inner side airbag 15 inflating unit

20 inflator body

20a generating surface 20b first exial end

20c second axial end 22 outlet openings 24a first stud

24b second stud

26 pyrotechnic load

30 deflector

32 end wall

33 hole

34 sleeve

34a, b, c section of sleeve / flap

34d, e, f three-layered section 35a, b, c slit

36 bending lines

40 blank for sleeve 42 hole

44 indention

60, 60 vehicle seat

62 frame

62 vehicle structure 64 external object

Claims

1 Airbag assembly comprising

an airbag and

an inflating unit (15) being located inside the airbag at least in sections, said inflating unit (15) comprising an oblong inflator body (20) extending from a first axial end (20b) to a second axial end (20c) and having a generating surface (20a) with outlet openings (22) being provided in an outlet area of the generating surface (20a) near the second axial end (20c) in a thrust- neutral manner, and a deflector (30) having a covering section covering at least some of the outlet openings (22), said covering section and said outlet area defining a free cross-section, wherein the deflector (30) deflects at least the majority of the gas exhausted through outlet openings (22) in a first axial direction towards the first axial end (20b) of the inflator body (20), characterized in that the gas streaming out of the outlet openings (22) when the inflator is triggered, deforms the covering section at least partially such that the free cross-section is enlarged.

2. Airbag assembly according to claim 1 , characterized in that the free cross- section is basically zero in the idle state of the inflating unit (15).

3. Airbag assembly according to claim 1 or claim 2, characterized in that the covering section is a sleeve (34) or a section of a sleeve (34). 4. Airbag according to claim 3, characterized in that the sleeve (34) comprises a main part and at least one flap (34a, 34b, 34c) bending outwardly when gas flows out of the outlet openings (22).

5. Airbag according to claim 4, characterized in that the sleeve (34) is folded such that it comprises at least one three-layered section (34d, 34e, 34f) in the idle state of the inflating unit (15). 6. Airbag assembly according to one of the claims 3 to 5, characterized in that the sleeve is held by at least one stud (24a) extending from the inflator body

(20).

7. Airbag assembly according to one of the claims 3 to 6, characterized in that the deflector consists exclusively of a sleeve being formed from a single blank (40).

8. Airbag assembly according to one of the claims 1 to 3, characterized in that the deflector is in form of a cap, wherein the cap is preferably crimped to the inflator body (20).

9. Airbag assembly according to one of the preceding claims, characterized in that the deflector (30) additionally deflects a part of the gas exhausted through the outlet openings (22) in second axial direction opposite the first axial direction.

10. Airbag assembly according to one of the preceding claims, characterized in that the airbag is a side airbag (10) adapted for being mounted to a vehicle seat (60, 60’), wherein the deflector (30) guides at least a part of the gas stream downwards.

1 1. Vehicle seat assembly comprising a vehicle seat and an airbag assembly according to claim 8 being attached to the vehicle seat.

12. Motor vehicle with a vehicle seat (60, 60’) and a vehicle seat assembly according to claim 9, wherein the airbag assembly is mounted to the vehicle seat (60, 60’) at the vehicle-inner side of the vehicle seat (60, 60’).

13. Inflating unit (15) for an airbag assembly according to one of the claims 1 to 8.