Gassack

Abstract

Gasbag (10), in particular a front gasbag, with an outer wall having a front wall (18) and a rear wall (24), a retaining strap (16) provided inside the gasbag (10) and an electrically actuated activation device (26) for releasing the retaining strap (16) so that it no longer exerts a restraining effect, wherein the gasbag (10) assumes a large or a small inflation volume depending on the actuation of the activation device (26), characterized in that the retaining strap (16) is composed of several retaining strap sections (30, 32) coupled to each other via a first tear seam (36) and a pulling element (40) is coupled to the activation device (26), which is coupled to the first tear seam (36) at its front end region in such a way thatthat when the activation device (26) is activated, the first tear seam (36) is destroyed by tension, and when inflated and the activation device (26) is not activated, the first tear seam (36) remains intact and the gas bag (10) has the smaller inflation volume.

Description

[0001] The invention relates to a gas bag, in particular a front gas bag, with an outer wall having a front and a rear wall, a retaining strap provided inside the gas bag and an electrically actuated activation device for releasing the retaining strap so that it no longer has a restraining effect, wherein the gas bag assumes a large or a small inflation volume depending on the actuation state of the activation unit.

[0002] These gas bags are specifically designed to provide a gas bag volume adapted to the containment situation. The gas bag can therefore assume two different geometries and two different volumes, depending on whether the retaining strap exerts a restraining effect on the front wall or not.

[0003] Furthermore, there are newer efforts to selectively influence the inflation and deployment behavior of the gasbag during the inflation process. This means that sections of the gasbag's outer wall are temporarily restrained during inflation to encourage expansion in other directions, and only then is the movement of the outer wall in the previously restrained area released. This temporary restraint is achieved primarily through rip seams on retaining straps, which are designed to rupture in every instance, i.e., during every inflation cycle.

[0004] In future piloted driving systems, it is expected that occupants may be reclined further back than usual in comfort positions, or that the seat may be moved further back than usual. This will necessitate even greater volume differences between the various airbag designs.

[0005] The object of the invention is to create a gas bag that can achieve large volume differences when fully inflated and that occupies the larger inflation volume when activated. At the same time, the gas bag should be able to be deployed in an optimized manner.

[0006] This problem is solved in a gas bag of the type mentioned above by the fact that the retaining strap is composed of several retaining strap sections coupled to each other via a first tear seam and a tensioning element is coupled to the activation device, which is coupled to the first tear seam at its front end (i.e. the end near the front wall) in such a way that when the activation device is actuated, the tear seam is destroyed by tension, namely by the tension generated by this movement of the front wall, and when inflated and the activation device is not actuated, the first tear seam remains intact and the gas bag has the smaller inflation volume.

[0007] In the gas bag according to the invention, the retaining strap is not simply released by the activation device, as is currently the case, or left attached when the activation device is not activated. Instead, actuating the activation device also causes the first tear seam to break, thus temporarily restraining the front wall during the inflation process. When the activation device is actuated, the retaining strap is destroyed, and the gas bag can assume its larger geometry with the greater inflation volume.

[0008] Preferably, the pulling element is attached to the safety strap at the first tear seam, i.e., the first tear seam connects at least three parts together, namely the two safety strap sections and the pulling element.

[0009] The controlled tearing, on the one hand, and the maintenance of the stability of the first tear seam, on the other, are achieved by the tensioning element having a front end. "Front" in this context means always closer to the front wall in the theoretically fully inflated state of the gas bag, ensuring that no part is damaged. From this front end, the tensioning element extends first towards the front wall to overlap the retaining strap. In this overlap area, the tensioning element is attached to the retaining strap by the first tear seam. After the tear seam, the tensioning element is folded over at an acute angle, with the folded portion no longer attached by the first tear seam. This folded section runs towards the activation device. The resulting technical effect is as follows.If the tensioning element is not released but remains anchored at its rear end, it exerts a so-called "peeling force" on the tear seam due to the change in direction after the first tear seam. The tear seam is unstable under this force and tears, because this peeling force tends to separate the tensioning element and the front wall laterally from each other. However, if the tensioning element is no longer held at its rear end, this "peeling" effect—i.e., the movement of the tensioning element laterally away from the safety strap—no longer occurs. The tear seam is then only subjected to shear stress and is strong enough to absorb the shear forces. The safety strap remains intact.

[0010] The first and second sections of the safety strap can only run parallel to each other in the area where they are attached and are subjected to tensile stress in opposite directions. This results in no "peeling" effect occurring between the safety strap sections in the area of ​​the first tear seam; instead, the first tear seam is only subjected to shear stress with respect to the force exerted on it by the safety strap sections.

[0011] The traction element can have a first part that is attached to the retaining strap at its front end by the first tear seam, or that merges integrally into a section of the retaining strap at the first tear seam. The traction element has at least a second part that is optionally detachably attached to the rear end of the first part. The term "optionally detachable" means that, depending on the actuation of the activation device, the first and second parts can be detached from each other or remain attached. This allows for an additional temporary restraint effect through a further optional detachment, which also temporarily controls the deployment.

[0012] In this context, the traction element can fork at the rear end of the first part into a second and a third part, which run side by side towards the rear wall and the activation device. The second part is permanently attached at its rear end, while the third part is coupled to the activation device at its rear end, meaning it is detachable at its anchoring point. However, the second part remains anchored at its rear end completely independent of the activation device's operating state. This anchoring point can generally be located in the area of ​​the module or the rear wall. This embodiment allows for a further subdivision of the movement of the retaining strap and, additionally, the traction element, so that the traction element either remains stable or breaks. The coupling of the three parts of the traction element is achieved, in particular, as follows.The first and second sections, in the area where they are attached to each other, run exclusively alongside each other in an overlap zone when a tensile force is applied, i.e., when the gas bag is unfolded and inflated, and are subjected to tensile stress in opposite directions. The third section extends from its front end towards the front wall and is attached to the first and second sections by a second tear seam. This second tear seam thus secures all three sections of the tensioning device together. However, after the second tear seam, the third section is folded over at an acute angle and runs towards the activation device. Here, as previously observed with the retaining strap, the effect of "peeling" occurs, i.e., the second tear seam is destroyed if the third section remains attached and the activation device is not engaged.When the activation device is engaged, the second part, because its anchoring does not release, does not exert any additional force on the second tear seam, and it remains intact. In this case, the first and second parts exert a pure shear force on the second tear seam due to the opposing tensile forces. This results in an additional positive effect for the airbag, as a tear seam can always be activated, regardless of whether the activation device is engaged or not. This allows the deployment movements to be influenced in both activation states, as the front wall is temporarily held back (until the tear seam is destroyed), and a lateral or upward / downward deployment movement is supported.

[0013] The gasbag can comprise a front and a rear chamber, which can be fluidically coupled and decoupled by a valve assembly. The valve assembly is coupled to the retaining strap and is opened by the retaining strap when the activation device is engaged. This allows the gasbag to be either compact when the valve assembly is closed or large when the valve assembly is opened by the activation device. The front chamber is then either inflated or deflated.

[0014] The front chamber is preferably positioned on top of the rear chamber. When the front chamber is deflated, its front wall rests against the front wall of the rear chamber. The front chamber may also be secured to the rear chamber's front wall by tethered seams when deflated. When the valve assembly is opened by actuating the activation device, these tethered seams tear, and the front chamber inflates / fills.

[0015] The rear chamber has a front wall that is closed except for the valve assembly, according to the preferred embodiment. When the activation device is not actuated, this front wall forms a support wall for the occupant, and a wall rests on this wall, forming the front wall of the uninflated front chamber. This wall is attached to the front wall of the rear chamber and forms a smaller gas bag placed on top of the rear chamber, which then constitutes the front chamber.

[0016] Two adjacent and spaced-apart retaining elements can attach to the front wall and inside the gas bag, to which the safety strap is coupled. The front wall is inverted at the retaining elements to create a smaller inflation volume; when the activation unit is engaged, the safety strap is released and the inversion is eliminated.

[0017] The restraints inside the airbag can be connected to each other via a corset lacing system coupled to the safety strap when the activation device is not engaged. A corset lacing system is a cross-lacing system that alternates back and forth between the two restraints.

[0018] Further features and advantages of the invention will become apparent from the following description and from the following drawings, to which reference is made. The drawings show: - Fig. 1 a side view of an embodiment of the gas bag according to the invention with small and large inflation volume, - Fig. 2 a schematic view of the gasbag interior according to a first variant with retaining strap and pulling device in the initial situation, - Fig. 3 A schematic view of the retaining strap and pulling mechanism with the activation device engaged and a large gas bag volume, - Fig. 4 A schematic view of the retaining strap and pulling mechanism with the activation device not activated and a small gas bag volume, - Fig. 5 a second embodiment in schematic side view of the gasbag according to the invention with a large gasbag volume, - Fig. 6 a front view of the gasbag according to the invention in a third embodiment with a small gasbag volume, - Fig. 7 a sectional view in side view through the gasbag to Fig. 6 with the activation device not activated, and - Fig. 8 a schematic view according to the arrow X in Fig. 7, which shows a corset lacing.

[0019] In Fig. Figure 1 shows a front airbag 10, which is housed in a vehicle's instrument panel 12 and is furthermore stored folded in an airbag module 14. The airbag 10 unfolds from the airbag module 14 in the event of an impending or ongoing accident.

[0020] The gasbag 10 can assume two different shapes: a small inflation volume (shown with solid lines) and a large inflation volume (shown with dashed lines). Therefore, the gasbag 10 can also assume two different geometries.

[0021] In particular, the large inflation volume should be available when an occupant is in a so-called comfort position, i.e., has either pushed the vehicle seat very far back and / or has reclined the backrest sharply; in all other cases, the small inflation volume should be used.

[0022] In order to be able to assume the different shapes, the gasbag 10 has inside one or more retaining straps 16, which are attached on the one hand to the front wall 18 with their front end 20 and on the other hand with their rear end 22 either to the gasbag module 14 or to the gasbag wall, e.g. on the rear wall 24 in the area of ​​the blowing mouth.

[0023] To control the two different states of the gasbag 10, an activation device 26 is housed in the gasbag module 14, for example, a pyrotechnically operated but electrically actuated activation device 26. Depending on the determined parameter, this device is either activated, i.e., actuated, or not. The different inflation volumes are achieved based on this. The gas generator 28 for inflating the gasbag 10 is typically a single-stage gas generator, but a multi-stage gas generator can also be used.

[0024] In Fig. Figure 1 shows the retaining strap 16 and the activation device 26 only very schematically; further details can be found in the Fig. 2, Fig. 3 to Fig. 4.

[0025] It should be emphasized in advance, however, that the principle of all the embodiments shown is to achieve the larger inflation volume when the activation device 26 is actuated.

[0026] Furthermore, the activation device is implemented, for example, in such a way that it releases the rear anchorage of a traction element described below, or destroys the traction element in the area of ​​the rear anchorage, so that it is no longer held.

[0027] In Fig. Figure 2 shows one way in which the tether strap 16 can be released.

[0028] The retaining strap 16 consists of a first retaining strap section 30, which is attached to the front wall 18 at its front end 20, and a second retaining strap section 32. The second retaining strap section 32 is permanently, i.e., non-removably, anchored at its rear end 34 in the area of ​​the gas bag module. The attachment can also be made to the rear wall, e.g., at the inlet nozzle, or to the gas generator or other components.

[0029] The safety strap sections 30 and 32 are separate, originally distinct parts that are joined together by a first tear seam 36. For this purpose, the front end region of safety strap section 32 and the rear end region of safety strap section 30 overlap. They form an overlap zone in which they run exclusively alongside each other; that is, when the safety strap 16 is subjected to tensile stress, there is no deflection into any area of ​​the safety strap sections 30 and 32 or in the overlap zone. The applied tensile forces act in the opposite direction. With sufficient tensile stress, the safety strap sections 30 and 32 exhibit a linear profile in side view, as shown in Fig. 2 can be seen, and this linear progression continues into the overlap area.

[0030] A tensile element 40 is attached to the tether band 16 by the tear seam 36, which is hereinafter referred to as the first tear seam 36, wherein the tensile element 40 can also consist of several parts, in the present embodiment of a first part 42 with a front end 44, which from the front end 44 first runs parallel to the tether band 16, i.e. also parallel to the tether band sections 30, 32, in order to then run after the tear seam 36 at an acute angle, here less than 180° or almost 180°, towards the rear wall 24 or module 14.

[0031] In the region of the rear end 46 of the first part 42, the tensile element 40 splits into a second part 48 and a third part 50, all of which are joined to each other by a second rupture seam 52. The design of the rupture seam 52 and the position of the individual parts correspond to the orientation and position of the respective parts at the first rupture seam 36. This means that the front end of the second part 48 extends over or under the rear end of the first part 42 and overlaps it, without any change in direction, and both parts 42 and 48, when under tensile stress, run linearly in side view.

[0032] However, the third part 50 extends from its front end 53 first parallel and overlapping to the overlapping first and second parts 42, 48, but then, i.e. after the second tear seam 52 and the corresponding overlap area of ​​the parts 42, 48, 50, at an acute angle backwards in the direction of the activation device 26.

[0033] The rear end 54 of the second part 48 is permanently attached, e.g., to the gasbag or to another part of the module, e.g., to the gas generator. The rear end 56 of the third part 50, however, is coupled to the activation device 26 and can be released when the activation device 26 is actuated. This is shown here, purely symbolically, as the rear end 56 is held in a sliding bracket 61, which can be released after being moved (see arrow).

[0034] Fig. Figure 2 shows the state in which the retaining strap 16 and the tensioning element 40 are also essentially taut, with neither the retaining strap 16 nor the tensioning element 40 being in the activated state of the gas generator 28. The sections and parts were previously explained in this "slightly" inflated state. Only in the Fig. 3 and Fig. Figure 4 shows the states that exist after the gas generator is activated.

[0035] In the embodiment according to Fig. 3 the gas generator is ignited, and the activation device 26 is actuated. This means that the rear end 56 of the third part 50 is released, whereas the rear end 54 of the second part 50 and the rear end 34 of the retaining strap 16 both remain anchored, either because they are attached to the gasbag or to some other part of the gasbag module.

[0036] When the activation device 26 is actuated, the second tear seam 52 remains stable, and tension is applied to the first tear seam 36 via the tensioning element 40 by keeping the first part 42 and the second part 50 attached to each other as the front wall 18 moves forward toward the occupants. The length of this tensioning element 40 is such that it is shorter than the distance between the rear end 34 and the tear seam 36, or, in other words, the tensioning element 40 is tightened before the section of the retaining strap 16 between the rear end 34 and the first tear seam 36 is tightened.

[0037] Due to the deflection of the first part 42 at an acute angle, the tear seam 36 experiences a force generated by a so-called peeling effect. Because of the deflection, the first part 42 tends to detach laterally from the overlap area of ​​the first tether section 30 and the second tether section 32. With this force direction, the first tear seam 36 is unstable and breaks, so that not only does the tensile element 40 detach from the tether 16, but the tether 16 also breaks into its two components. This means that the tether 16 is destroyed, no longer active, and the two tether sections 30 and 32 are no longer attached to each other as described. Fig. 3 shows.

[0038] This allows the larger gasbag volume to be achieved. During the deployment process, however, the gasbag 10 was briefly held back, namely when the tension on the tensioning device 40 was first triggered, until the second tear seam 36 was destroyed. This temporarily prevents the front wall 18 from deploying, and the incoming gas deploys other sections of the gasbag.

[0039] Fig. Figure 4 shows the situation when the activation device 26 is not actuated, thus enabling the smaller gasbag volume. In this case, the rear end 56 remains anchored. For the same reason, namely the peeling effect, the second tear seam 52 is destroyed, causing the first part 42 to detach from both the second part 48 and the third part 50. The tension element 40 is destroyed and exerts no force on the first tear seam 36. This means the peeling effect no longer occurs. The first tear seam 36 is now only subjected to shear stress, and this stress does not lead to the destruction of the tear seam 36.

[0040] Thus, the retaining strap 16 remains intact and can prevent the front wall 18 from moving further towards the occupant.

[0041] In the variant according to Fig. The gasbag 10 has a rear chamber 60 and a front chamber 62 located on top of the rear chamber 60. The front chamber 62 is closer to the occupant and is formed by a gasbag wall 64 sewn onto the front wall 18 of the rear chamber 60. The front wall 18 also borders the front chamber 62 at its rear end.

[0042] The front wall 18 has one or more overflow openings 66, through which a flow connection between the chambers 60, 62 can be established.

[0043] A valve assembly 68 closes one or more overflow openings 66 in the initial state. The valve assembly 68 can, for example, be a fabric section or another flexible, flat component located inside the first chamber 60 and connected to the front wall 18, e.g., via tear seams 70.

[0044] The valve assembly 68 is actuated by the retaining strap 16 and can be moved from its originally closed state to an open state. The retaining strap 16 also has a first section 30 that extends to a first tear seam 36, where the first retaining strap section 30 is connected to a second retaining strap section 32. The rear end 34 of the retaining strap 16 is again permanently attached to the module or the gasbag.

[0045] In contrast to the embodiment according to the Fig. 2, Fig. 3 to Fig. 4. Here, the second retaining strap section 32 and the traction element 40 merge seamlessly into one another. This means that the corresponding part first runs from the rear end 34 to the first tear seam 36 and, after the first tear seam 36, at an acute angle back towards the module, where the other end is coupled to the activation device 26. This variant can, of course, also be used in the embodiment according to the Fig. 2, Fig. 3 to Fig. 4 will be realized.

[0046] When the activation device 26 is actuated, the rear end of the tension member 40 is no longer fixed, so that no force can be exerted on the first tear seam 36 via the tension member 40 and it remains stable. This, in turn, means that the valve device opens, because when the front wall 18 is moved forward, the retaining strap 16 is subjected to tension and tears open the valve device 68 by releasing the tear seams 70.

[0047] The overflow opening 66 is unobstructed, allowing gas to flow from the rear chamber 60 into the front chamber 62, and both chambers 60 and 62 are inflated. The gas bag 10 has the larger volume.

[0048] However, if the activation device 26 is not actuated, the tensioning element 40, when tightened, exerts a force on the first tear seam 36, causing it to break. The retaining strap 16 is then also broken, and no force is exerted on the valve device 68; the overflow opening 66 remains closed, and the second chamber 62 is not inflated. The so-called support wall 80, i.e., the front wall of the second chamber 62, rests on the front wall 18.

[0049] Fig. Figure 6 shows the front wall 18 of another gas bag 10 in its low inflation state. It can be seen that the front wall 18 is recessed in a central area 82. Laterally, the central area 82 is bounded by two linear areas 84 and 88, which are essentially parallel to each other and spaced apart laterally. Fig. Figure 7 shows a schematic cross-section through the gasbag 10. The areas 84 and 88 are formed by two adjacent and spaced-apart retaining elements 90 engaging the front wall 18 and causing the front wall 18 to be inverted, as shown in the section in Figure 7. Fig. Figure 7 shows a somewhat exaggerated view. The retaining means 90 can be stitched areas of the front wall 18 or, for example, sewn-on straps. The opposing retaining means 90 have holes 92 or corresponding eyelets which are inserted into Fig. 8 are shown and are connected to each other via a so-called corset lacing 94.

[0050] Corset lacing is defined by a cross-shaped lacing pattern.

[0051] The tether strap 16 attaches to the corset lacing. In Fig. Figure 7 does not show in detail how the tethering band 16 can be destroyed or remain active. Reference can be made to the preceding figures, which all show options for developing this mechanism.

[0052] If the retaining strap 16 remains undamaged, the corset lacing 94 will also not loosen, and the gasbag will remain in place. Fig. 7 smaller form shown. However, if the retaining strap 16 is destroyed because the activation device 26 is actuated, the corset lacing 94 can come loose, and more surface area of ​​the front wall 18 is available to bulge outwards, so that the gasbag can occupy the larger gasbag volume.

Claims

[1] Gas bag (10), in particular a front gas bag, with an outer wall having a front wall (18) and a rear wall (24), a retaining strap (16) provided inside the gas bag (10) and an electrically actuated activation device (26) for releasing the retaining strap (16) so that it no longer has a restraining effect, wherein the gas bag (10) assumes a large or a small inflation volume depending on the actuation of the activation device (26), characterized by, that the retaining strap (16) is composed of several retaining strap sections (30, 32) coupled to each other via a first tear seam (36) and a tensile element (40) is coupled to the activation device (26), which is coupled to the first tear seam (36) at its front end region in such a way that when the activation device (26) is actuated the first tear seam (36) is destroyed by tension and when inflated and the activation device (26) is not actuated the first tear seam (36) remains intact and the gas bag (10) has the smaller inflation volume. [2] Gas bag (10) according to claim 1, characterized by, that the traction element (40) merges integrally into one of the tether sections (32), wherein the tether section (32) is permanently attached at its rear end (34) and extends towards the front wall (18) to overlap with the other tether section (30), wherein the two tether sections (30, 32) are connected to each other in the overlap area via the first tear seam (36), and wherein with the first tear seam (36) the tether section (32) merges integrally into the traction element (40), which after the first tear seam (36) is folded at an acute angle to extend towards the activation device (26). [3] Gas bag (10) according to claim 1, characterized by , that the traction element (40) is attached to the tether strap (16) by the first tear seam (36). [4] Gasbag (10) according to claim 3, characterized by, that the traction element (40) has a front end (44) and from this extends first towards the front wall (18) to overlap with the retaining strap (16) and is attached to the retaining strap (16) in the overlap area with the first tear seam (36) and is folded over at an acute angle after the first tear seam (36) to extend towards the activation device (26). [5] Gas bag (10) according to any one of the preceding claims, characterized by , that the first and second sections of the retaining strap (30, 32) run exclusively alongside each other in the area where they are attached to each other and are subjected to tensile stress in opposite directions. [6] Gas bag (10) according to any one of the preceding claims, characterized by, that the traction element (40) has a first part (42) which is attached to the tether strap (16) at the first tear seam (36) in the area of ​​its front end (44) or which merges in one piece into a tether strap section (32) in the area of ​​the first tear seam (36), wherein the traction element (40) has a second part (48) which is detachably and controllably attached to the first part (42) in the area of ​​a rear end (46) of the first part (42). [7] Gas bag (10) according to claim 6, characterized by , that the traction element (40) forks in the area of ​​the rear end (46) of the first part (42) into a second part (48) and a third part (50), which run side by side towards the rear wall (24) and activation device (26), wherein the second part (48) is permanently attached at the rear end and the third part (50) is coupled to the activation device (26) at its rear end (56). [8] Gas bag (10) according to claim 6 or 7, characterized by, that the first and second parts (42, 48) run exclusively side by side in an overlap area where they are attached to each other and are subjected to tensile stress in opposite directions, and that the third part (50) extends at its front end (53) towards the front wall (18), first with a second tear seam (52) on the first and second parts (42, 48) and after the second tear seam (52) is folded over at an acute angle and extends towards the activation device (26). [9] Gas bag (10) according to any one of the preceding claims, characterized by , that the gas bag (10) comprises a front and a rear chamber (62, 60) which can be coupled and uncoupled fluidically by means of a valve device (68), wherein the valve device (68) is coupled to the retaining strap (16) and is opened by the retaining strap (16) when the activation device (26) is actuated. [10] Gas bag (10) according to claim 9, characterized by, that the front chamber (62) sits on the rear chamber (60). [11] Gas bag (10) according to claim 10, characterized by , that the rear chamber (60) has a front wall (18) which is closed except for the valve assembly (68), which, when the activation device (26) is not actuated, forms a support wall for the occupant and on which rests a wall which forms the front wall of the uninflated, front chamber (62), which is attached to the front wall (18) of the rear chamber (60). [12] Gas bag (10) according to any one of claims 1 to 9, characterized by , that two retaining means (90) positioned next to and apart from each other engage the front wall (18) and the inside of the gas bag, to which the retaining strap (16) is coupled, wherein the front wall (18) is inverted by the retaining means (90) to form the smaller inflation volume, wherein when the activation device (26) is actuated the retaining strap (16) is released and the inversion is omitted. [13] Gas bag (10) according to claim 12, characterized by , that the retaining means (90) inside the gasbag are connected to each other via a corset lacing (94) coupled to the retaining strap (16) when the activation device (26) is not activated.

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