DE20310575U1 - Blower system for inflating airbag has tubular gas generator with closed ends and aperture at midpoint releasing gas into manifold with two outlets - Google Patents

Abstract

The airbag inflating system has a gas generator (1) which is cylindrical and closed at both ends. The gas escapes through an aperture (15) at its midpoint into a manifold (2) with an outlet (27,28) at each end. The manifold is rectangular, with a central V-shaped indentation, forming an obtuse-angled edge (25) facing the outlet from the gas generator. The gas is equally divided into two streams (G1,G2).

Description

TAKATA-PETRI AG
Bahnweg 1

63743 Aschaffenburg
10

PTR463

Inflation device for inflating a gas bag Description

The invention relates to an inflation device for inflating a gas bag according to the preamble of claim 1.

Such an inflation device comprises a gas generator with at least one discharge opening through which gas can flow out of the gas generator along an outflow direction; with a gas guide device arranged downstream of the discharge opening, by means of which the gases flowing out of the discharge opening are guided into the gas bag to be inflated; and gas guide surfaces of the gas guide device,

through which the gases are guided in a defined direction. 40

The invention is based on the problem of further improving an inflation device of the type mentioned at the beginning.

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This problem is solved according to the invention by providing an inflation device with the features of claim 1.

According to this, the gas guiding device comprises two gas guiding surfaces which extend along different spatial directions and - viewed along the outflow direction of the gases from the gas generator - meet behind the outflow opening of the gas generator, so that the gas flow emerging from the outflow opening is split into at least two partial flows, each of which is guided along one of the two gas guiding surfaces.

The two partial flows can be fed to the gas bag to be inflated in a defined manner along the respective gas guide surface, avoiding flow losses. This is intended to ensure that the gases flow into the gas bag to be inflated with as little turbulence as possible.

The gas guide surfaces of the gas guide device act as impact and guide surfaces for the gases flowing out of the gas generator.

The area in which the two gas guide surfaces meet is preferably located behind the outflow opening of the gas generator in such a way that it is cut by a vertical line on the base area (cross-sectional area) of the outflow opening. At the same time, this area - viewed along the vertical line on the cross-sectional area of the outflow opening - is at a smaller distance from the outflow opening than the other areas of the gas guide surfaces.
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Viewed from the outflow opening, the two gas guide surfaces preferably form an angle of more than 180°, whereby the two gas guide surfaces can meet to form an edge on the one hand or to form a curved (curved) transition area on the other. The two gas guide surfaces therefore form a convex surface when viewed from the outflow opening of the gas generator, whereby the term "convex" should be understood in such a general way that it also includes the embodiment according to which the two gas guide surfaces meet to form an edge.

Each of the two gas guide surfaces extends, as seen from the gas generator's discharge opening, along a spatial direction which results from a combination (superposition) of a vertical on the cross-sectional area of the

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outflow opening and a perpendicular to this vertical. The two spatial directions differ in that the perpendicular to the vertical is oriented oppositely for one spatial direction to that for the other spatial direction.
5

The two gas guide surfaces are each part of a channel that extends from the outflow opening of the gas generator to at least one outlet of the gas guide device, whereby according to one variant a single outlet is provided at the end of the respective channel and according to another variant one or more outlets are arranged one behind the other along the channel. The size of the individual outlets preferably increases in the direction of extension of the respective channel.

Depending on the direction in which the gas from the gas generator is to be introduced into the gas bag to be inflated, the outlets of the channels can be oriented parallel, inclined or perpendicular to the cross-sectional area of the discharge opening of the gas generator.

According to a further development of the invention, the channels can be structured in such a way that the gas flow exiting the gas generator is split into more than two partial flows, e.g. by forming two or more partial flows in each of the channels.

Furthermore, it can be provided that the channels widen towards the outlets in order to ensure optimal flow conditions for the gas to be introduced into the gas bag. The gas guide surfaces of the channels can be either flat or curved.

According to one embodiment, the gas guide device as a whole is designed symmetrically with respect to at least one plane extending through the connecting area of the two gas guide surfaces. As a result, the two partial flows of the gas flow originating from the gas generator are guided further into the airbag under the same conditions. However, an asymmetrical design of the gas guide device is also possible in order to specifically create different flow conditions in the partial flows of the gas flow.

The solution according to the invention is particularly suitable for use in longitudinally extended gas generators (tubular gas generators) with a - based on their

EM 03/51

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Longitudinal extension - central discharge opening. Such gas generators often have a plurality of discharge openings arranged one behind the other along their circumference, for safety reasons alone. In such a case, the discharge openings of the gas generator that are not required can be closed during or after installation of the gas generator in the inflation device according to the invention.

10

The gas flow can be separated into partial flows in such a way that the partial flows run obliquely along the longitudinal axis of the tubular gas generator, or in such a way that the partial flows are directed essentially perpendicular to the longitudinal axis of the tubular gas generator.

15

In order to optimize the flow conditions in the gas guiding device, which can in particular be a component of a housing enclosing the gas generator, the (total) cross-sectional area of the outlets of the gas guiding device is preferably larger than the cross-sectional area of the active (unclosed) outflow opening(s) of the gas generator.

20 25

Further features and advantages of the invention will become clear from the following description of embodiments with reference to the figures.

Show it:

Fig. 1 is a side view of a gas generator for inflating a gas bag with an associated gas guiding device;

Fig. 2 is a perspective view of the gas guiding device from Figure 1;

30

Fig. 3 shows a modification of the gas guiding device from Fig. 2 with regard to the arrangement of the outlets of the gas guiding device;

Fig. 4 shows a modification of the gas guiding device from Fig. 2 with regard to the design of the gas guiding surfaces;

Fig. 5 shows a modification of the gas guiding device from Fig. 2 with regard to the orientation of the outlets of the gas guiding device;

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Fig. 6 shows a modification of the gas guiding device from Figure 2 with regard to the arrangement and orientation of the outlets;

Fig. 7 shows a modification of the gas guiding device from Figure 2 with regard to the design of the gas guiding surfaces and the arrangement and orientation of the outlets;

Fig. 8 shows a modification of the gas guiding device from Figure 2 with regard to the

Structuring of the gas guiding surfaces;
10

Fig. 9 shows a modification of the gas guiding device from Fig. 2, wherein the gas guiding surfaces widen towards the outlets of the gas guiding device;

Fig. 10 shows a modification of the gas guiding device from Fig. 9 with regard to the orientation of the partial flows of the gas flow emerging from the gas generator, formed by the gas guiding device;

Fig. 11 a modification of the gas guide device from Figure 2 with lower

Symmetry;
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Fig. 12 shows a further modification of the gas guiding device from Figure 2 with less symmetry.

Figure 1 shows a gas generator 1 in the form of a tubular gas generator with a longitudinal axis L and an outflow opening 15 arranged centrally with respect to the longitudinal axis L, which is intended for inflating a gas bag in an airbag module for motor vehicles. The gas generator 1 is arranged in a housing 10 which has a gas guide device 2 for the gases flowing out of the outflow opening 15.
30

Usually, a tubular gas generator of the type shown in Figure 1 has a number of outlet openings arranged one behind the other along its circumference for safety reasons. This ensures that if the gas generator is accidentally triggered before installation in a motor vehicle, the gases escaping through the outlet openings do not lead to a strong acceleration of the gas generator in one direction. In this case, the unnecessary

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Discharge openings of the tubular gas generator 1 are closed, for which purpose, for example, closure means formed on the housing 10 can be used.

10

The gas guide device is arranged behind the outflow opening 15, viewed along the flow direction of the gases flowing out of the outflow opening 15, and has a housing 20 which forms two channels 21, 22, each of which extends from the outflow opening 15 to an outlet 27 or 28 and which each have a gas guide surface 23, 24 serving as an impact and guide surface for the gases flowing out of the outflow opening 15, see also Fig. 2.

The two gas guide surfaces 23, 24 each extend along a spatial direction R1 or R2, which results from a superposition (linear combination) of the vertical V on the base area (cross-sectional area) of the outflow opening 15 and a perpendicular S1, S2 thereto, wherein the two perpendiculars S1, S2 run in opposite directions along the longitudinal axis L of the tubular gas generator 1. As a result, the two spatial directions R1, R2, which define the extent of the gas guide surfaces 23, 24, each extend obliquely inclined along the longitudinal axis L of the tubular gas generator 2.

The two oppositely inclined gas guide surfaces 23, 24 of the gas guide device 2 meet immediately behind the outflow opening 15 of the gas generator 1 in a transition region 25 designed as an edge, which is intersected by the vertical V running through the center of the circular outflow opening 15. The two gas guide surfaces 23, 24, viewed from the outflow opening 15, form an obtuse angle α > 180 °.

The edge 25 further forms that portion of the gas guide surfaces 23, 24 with the smallest vertical distance (relative to the vertical V on the outflow opening 15 of the gas generator) from the outflow opening 15 or the surface of the gas generator 1 as a whole.

The two channels 21, 22 are each closed at the side by a boundary wall 20a, 20b of the housing 20 of the gas guide device 2 and the housing 20 is open on its underside 20c located directly above the gas generator 1, so that the gases emerging from the outflow opening 15 of the gas generator 1 can easily reach the interior of the gas guide device 2. The gases initially flow essentially along the vertical V onto the cross-sectional area of the outflow opening

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15 and are then divided by the gas guide surfaces 23, 24 acting as impact and guide surfaces into two gas flows G1, G2, which are guided in the respective channel 21 or 22 to the outlet 27, 28 provided at the end of the channel 21 or 22 and exit from the gas guide device 2 there to inflate a gas bag. The gas bag can, for example, be folded essentially next to the inflation device 1, 2, as is known from WO 96/25 309 A1.

As a result, the gas flow exiting the outflow opening 15 essentially along the vertical V is split into two partial flows G1, G2 by means of the gas guide surfaces 23, 24 of the gas guide device 2, with each gas flow being guided through the gas guide surfaces 23, 24 to the respective outlet 27, 28 of the gas guide device 2 with minimal flow losses (avoiding the formation of turbulence). The exit direction of the partial flows G1, G2 from the respective outlet 27, 28 is determined by its respective spatial orientation, with the cross-sectional area of the outlets 27, 28 being oriented essentially parallel to the cross-sectional area of the outflow opening 15, corresponding to an exit direction essentially perpendicular to the longitudinal axis L of the tubular gas generator 1.

Figure 3 shows a first modification of the gas guide device from Figures 1 and 2, the difference being that in the gas guide device shown in Figure 3 the outlets 27, 28 are provided in the lateral boundary surfaces 20a, 20b of the gas guide device 2 (and not adjacent to the gas guide surfaces 23, 24 as in the embodiment shown in Figure 2). As a result, the outlets 27, 28 are oriented essentially perpendicular to the cross-sectional area of the outflow opening of the gas generator and the gases exit from the outlets 27, 28 along the longitudinal axis of the tubular gas generator.

Figure 4 shows a further modification of the gas guide device from Figure 2, the difference being a curved (arched) design of the gas guide surfaces 23', 24' and accordingly also of the transition region 25' between the two gas guide surfaces. Viewed from the outflow opening of the gas generator, the gas guide surfaces 23', 24' together with the transition region 25' form a convex surface in the narrower sense.
35

In the modification of the gas guiding device from Figure 2 shown in Figure 5, the outlets 27, 28 of the channels 21, 22 are again immediately adjacent to the respective

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Gas guide surfaces 23 and 24 are arranged; however, they run inclined to the cross-sectional area of the discharge opening of the associated gas generator or to its longitudinal axis.

In the gas guiding device shown in Figure 6, an outlet 27' or 28' is integrated into each gas guiding surface 23, 24 of the gas guiding device 2. The outlets 27', 28' widen in the direction away from the connecting region 25 of the gas guiding surfaces 23, 24 and towards the lateral boundary walls 20a ₁ 20b of the channels 21, 22.

Figure 7 shows a gas guiding device 2 with curved gas guiding surfaces 23', 24' and a curved transition region 25', as shown in Figure 4, but according to Figure 7, several, namely three, outlets 29a, 29b, 29c are arranged one behind the other in each gas guiding surface 23', 24'. The cross-sectional area, i.e. the diameter, of the circular outlets 29a, 29b, 29c increases along the direction from the transition region 25' towards the lateral boundary walls 20a, 20b of the gas guiding device 2.

The gas guide device 2 shown in Figure 8 is a further development of the one shown in Figure 5, wherein the channels 21a, 21b and 22a, 22b are each structured, i.e. divided into sub-channels, in such a way that the gas flow exiting the gas generator is divided into a total of four sub-streams. Accordingly, each sub-channel 21a, 21b of one channel and 22a, 22b of the other channel is assigned its own outlet 27a, 27b or 28a, 28b, through which the gas of the respective sub-stream can reach the gas bag to be inflated.

Furthermore, in the gas guide device shown in Figure 8, the connecting edge 25 of the two gas guide surfaces 23, 24 extends along the longitudinal axis of the associated gas generator, so that the gas guide surfaces 23, 24 themselves run perpendicular to that longitudinal axis. In contrast, in all previous embodiments, the connecting region 25 ran perpendicular to the longitudinal axis L of the gas generator 1 and the gas guide surfaces 23, 24 ran, albeit inclined, along that longitudinal axis L, see in particular Figure 1.

Figure 9 shows a modification of the gas guide device from Figure 2, in which the gas guide surfaces 23", 24" each expand along the direction away from the connecting edge 25. This expansion continues in the outlets 27", 28" immediately adjacent to the gas guide surfaces 23", 24". Accordingly, an expansion also takes place

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of the channels 21", 22" of the gas guiding device 2 perpendicular to their respective direction of extension.

Figure 10 shows a modification of the gas guide device from Figure 9, the difference being that in the gas guide device according to Figure 10 (as in the case of the gas guide device from Figure 8), the gas guide surfaces 23", 24" guide the partial flows of the gas flowing out of the gas generator essentially perpendicular to the longitudinal axis of the associated gas generator. The outlets 27", 28" of the two channels 21", 22" of the gas guide device 2 extend in a slot-like manner along the longitudinal axis of the associated gas generator and can, if necessary, extend along a substantial part of the length or even the entire length of the gas generator or the associated airbag module.

The embodiments of a gas guide device described so far with reference to Figures 1 to 10 are each characterized, among other things, by the fact that the gas guide device 2 is designed symmetrically with respect to a plane running through the respective connection region 25, 25' perpendicular to the longitudinal axis L of the gas generator 1 and with respect to a plane running along the longitudinal axis L of the gas generator 1 (plane spanned by the longitudinal axis L of the gas generator 1 and the vertical V on the outflow opening 15). This is not the case with the gas guide devices 3 shown in Figures 11 and 12. In particular, in these gas guide devices 3, the gas guide surfaces 33, 34 of the channels 31, 32 are not simply inclined in opposite directions to one another; instead, the extension directions of the gas guide directions 33, 34 are freely selected with regard to the desired direction of injection of the gases into an associated gas bag. The same applies to the arrangement and design of the outlets 37, 38 of the respective gas guiding device 3.

Furthermore, in the gas guiding devices shown in Figures 11 and 12, the gas guiding surfaces 33, 34 each meet in a connecting region 35 designed as an edge and are part of a channel 31, 32 of the gas guiding device 3, which, viewed along the direction of extension of the associated gas generator, is delimited by lateral boundary walls 30a, 30b of the housing 30 of the gas guiding device 3. The underside 30c of the respective housing 30 is open in order to allow gas to flow into the gas guiding device 3.

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Starting from the (asymmetrical) gas guiding devices 3 shown in Figures 11 and 12, a large number of further modifications are conceivable in order to adapt the partial flows in the individual channels 31, 32 of the respective gas guiding device 3 to special requirements. For example, the gas guiding surfaces 33, 34 can have different lengths and/or widths; the outlets 37, 38 can have different positions, orientations and/or sizes; the boundary walls of the channels 31, 32 can be designed differently, etc. The only decisive factor is that the gas flow emerging from the gas generator is split into two partial flows, which are guided along different spatial directions by means of the respective gas guiding surfaces, with the transition region between the two gas guiding surfaces preferably being arranged directly behind the outflow opening of the gas generator and having the smallest vertical distance from the outflow opening of all the areas of the gas guiding surfaces.

Claims (27)

1. Inflation device for inflating an airbag for the protection of occupants of a motor vehicle with - a gas generator, - at least one outflow opening of the gas generator through which gas can flow out of the gas generator along an outflow direction, - a gas guide device arranged downstream of the outlet opening, by means of which the gases flowing from the gas generator are guided into the gas bag to be inflated, and - Gas guide surfaces of the gas guide device, by means of which the gases are diverted and guided in the gas guide device, characterized ,
that the gas guiding device has two gas guiding surfaces ( 23 , 24 ; 23 ', 24 '; 23 ", 24 "; 33 , 34 ) which extend along different spatial directions (R1, R2) and which - viewed along the outflow direction of the gases - meet behind the outflow opening ( 15 ), so that the gas flow emerging from the outflow opening ( 15 ) is separated into at least two partial flows (G1, G2), each of which is guided along one of the two gas guiding surfaces ( 23 , 24 ; 23 ', 24 '; 23 ", 24 "; 33 , 34 ). 2. Inflation device according to claim 1, characterized in that the region ( 25 , 25 ', 35 ) in which the two gas guide surfaces ( 23 , 24 ; 23 ', 24 '; 23 ", 24 "; 33 , 34 ) meet is cut by a vertical (V) on the base surface of the outflow opening ( 15 ). 3. Blow-out device according to claim 2, characterized in that the outflow direction of the gases from the gas generator ( 1 ) runs along the vertical (V) to the outflow opening ( 15 ). 4. Inflation device according to one of the preceding claims, characterized in that the region ( 25 , 25 ', 35 ) in which the two gas guide surfaces ( 23 , 24 ; 23 ', 24 '; 23 ", 24 "; 33 , 34 ) meet, viewed along a vertical (V) on the base surface of the outflow opening ( 15 ), has a smaller distance from the outflow opening ( 15 ) than the other regions of the gas guide surfaces ( 23 , 24 ; 23 ', 24 '; 23 ", 24 "; 33 , 34 ). 5. Inflation device according to one of the preceding claims, characterized in that the two gas guide surfaces ( 23 , 24 ; 23 ', 24 '; 23 ", 24 "; 33 , 34 ), viewed from the outflow opening ( 15 ), form an angle (α) of more than 180°. 6. Inflation device according to claim 5, characterized in that the two gas guide surfaces ( 23 , 24 ; 23 ", 24 "; 33 , 34 ) meet at an obtuse angle to form an edge ( 25 , 35 ). 7. Inflation device according to claim 5, characterized in that the gas guide surfaces ( 23 ', 24 ') meet to form a curved transition region ( 25 '). 8. Inflation device according to one of the preceding claims, characterized in that the gas guide surfaces ( 23 , 24 ; 23 ', 24 '; 23 ", 24 "; 33 , 34 ), viewed from the outflow opening ( 15 ), form a convex surface. 9. Inflation device according to one of the preceding claims, characterized in that the two gas guide surfaces ( 23 , 24 ; 23 ', 24 '; 23 ", 24 "; 33 , 34 ), viewed from the outflow opening ( 15 ), each extend along a spatial direction (R1, R2) which results from a combination of a vertical (V) to the base area of the outflow opening ( 15 ) and a perpendicular (S1, S2) to the vertical (V). 10. Inflation device according to claim 9, characterized in that the two perpendiculars (S1, S2) are directed oppositely to the vertical (V). 11. Inflation device according to one of the preceding claims, characterized in that the two gas guide surfaces ( 23 , 24 ; 23 ', 24 '; 23 ", 24 "; 33 , 34 ) are part of a channel ( 21 , 22 ; 21a , 21b ; 22a , 22b ; 21 ", 22 "; 31 , 32 ) which extends from the outflow opening ( 15 ) to at least one outlet ( 27 , 28 ; 27 ', 28 '; 27 ", 28 "; 29a , 29b , 29c ; 37 , 38 ) of the gas guide device ( 2 , 3 ). 12. Inflation device according to claim 11, characterized in that the outlet ( 27 , 28 ; 27 ", 28 "; 37 , 38 ) is arranged at the end of the channel ( 21 , 22 ; 21 ", 22 "; 31 , 32 ). 13. Inflation device according to claim 11 or 12, characterized in that at least one outlet ( 27 ', 28 '; 29 a, 29 b, 29 c) is formed in the respective gas guide surface ( 23 , 24 ; 23 ', 24 '). 14. Inflation device according to one of claims 11 to 13, characterized in that the base surface of the at least one outlet ( 27 , 28 ; 27 ', 28 '; 27 ", 28 "; 29a , 29b , 29c ; 37 , 38 ) runs parallel, inclined or perpendicular to the base surface of the outflow opening ( 15 ). 15. Inflation device according to one of claims 11 to 14, characterized in that the channels ( 21 a, 21 b; 22 a, 22 b) are structured such that more than two partial flows of the gas flow exiting the gas generator ( 1 ), in particular two partial flows per channel ( 21 a, 21 b; 22 a, 22 b), are formed. 16. Inflation device according to one of claims 11 to 15, characterized in that the channels ( 21 ", 22 ") widen towards their end facing away from the outflow opening ( 15 ). 17. Inflation device according to one of the preceding claims, characterized in that the gas guide surface ( 23 , 24 ; 23 ", 24 "; 33 , 34 ) is flat. 18. Inflation device according to one of claims 1 to 16, characterized in that the gas guide surface ( 23 ', 24 ') is curved. 19. Inflation device according to one of the preceding claims, characterized in that the gas guiding device ( 2 ) is designed symmetrically with respect to at least one plane of symmetry. 20. Inflation device according to one of claims 1 to 18, characterized in that the gas guiding device has no plane of symmetry. 21. Inflation device according to one of the preceding claims, characterized in that the region ( 25 , 25 ', 35 ) in which the gas guide surfaces ( 23 , 24 ; 23 ', 24 '; 23 ", 24 "; 33 , 34 ) meet extends linearly. 22. Inflation device according to one of the preceding claims, characterized in that the gas generator ( 1 ) is longitudinally extended, in particular is designed as a tubular gas generator. 23. Inflation device according to claim 22, characterized in that the partial flows (G1, G2) run obliquely along the longitudinal axis (L) of the gas generator ( 1 ). 24. Inflation device according to claim 22, characterized in that the partial flows run substantially perpendicular to the longitudinal axis (L) of the gas generator ( 1 ). 25. Inflation device according to one of claims 22 to 24, characterized in that the outflow opening ( 15 ) is arranged centrally with respect to the longitudinal axis (L) of the gas generator ( 1 ). 26. Inflation device according to one of the preceding claims, characterized in that the gas guide device ( 2 ) is part of a housing ( 10 ) enclosing the gas generator ( 1 ). 27. Inflation device according to one of the preceding claims, characterized in that the total base area of the outlets ( 27 , 28 ; 27 ', 28 '; 27 ", 28 "; 29a , 29b , 29c ; 37 , 38 ) of the gas guiding device ( 2 , 3 ) is overall larger than the base area of the outflow opening ( 15 ) of the gas generator ( 1 ).