Air bag comprising a valve

Abstract

An air bag has an outflow opening (14) in an outer wall (12), which outflow opening is covered by a valve (16), wherein the valve (16) comprises at least two flexible valve elements (18) which are located adjacently to one another along a circumferential edge (20) of the outflow opening (14). Each valve element (18) has an outer edge (22) which is located at the circumferential edge (20) of the outflow opening (14) and is fixedly fastened there at least in portions, and each valve element (18) has a surface portion (28) which extends from the circumferential edge (20) into the surface of the outflow opening (14) and, in the region of the outflow opening (14), ends in an inner edge (24). The surface portions (28) are at least partially unattached to each other in the region of the outflow opening (14) and are movable perpendicularly to the surface of the outflow opening (14), so that the gas flow through the outflow opening (14) is variable. The surface portions (28) of adjacent valve elements (18) partially overlap.

Description

[0001] Gasbag with valve

[0002] The invention relates to a gas bag with a valve, in particular for a vehicle occupant protection system.

[0003] To protect a vehicle occupant, airbags are filled with high gas pressure in a short time. However, the optimal protective effect of an airbag also depends on its internal pressure. For example, a gasbag with a high internal pressure is often more beneficial for a large, heavy vehicle occupant, while a gasbag with a lower internal pressure may provide better protection for a small, light vehicle occupant. Different distances between the vehicle occupant and the airbag can also be better compensated for by adjusting the internal pressure. Likewise, for airbags that can be filled with different volumes, a volume-independent internal pressure can be set.

[0004] Adjusting the internal pressure should be as simple as possible, which is why passive valves are advantageous. These are valves that open and close purely by the internal pressure and do not include any additional mechanical, electrical, or pyrotechnic control mechanisms.

[0005] The object of the invention is to create a gas bag with a passive valve that is easy to manufacture and cost-effective.

[0006] This object is achieved by a gas bag with an outflow opening in an outer wall, wherein the outflow opening is covered by a valve comprising at least two flexible valve elements arranged next to one another along a peripheral edge of the outflow opening. Each valve element has an outer edge which is arranged on the peripheral edge of the outflow opening and is firmly fixed there, at least in sections. In addition, each valve element has a surface section which extends from the peripheral edge into the surface of the outflow opening and ends in an inner edge in the region of the outflow opening. The surface sections are at least partially unattached to one another in the region of the outflow opening. The surface sections are also movable perpendicular to the surface of the outflow opening, such that the outflow opening has a variable gas flow. The surface sections of adjacent valve elements overlap in sections.

[0007] This results in an arrangement of overlapping valve elements around the discharge opening. In particular, the valve elements can be arranged in a scale or iris-like pattern around the discharge opening.

[0008] The higher the internal pressure in the gas bag, the more the surface sections of the valve elements are pushed outward perpendicular to the surface of the discharge opening, and the higher the gas flow through the now-open valve. However, if the internal pressure in the gas bag drops below a certain value, the valve elements press against each other and together seal the surface of the discharge opening to the maximum degree. The valve is then closed. The valve is therefore a pressure-adaptive passive valve.

[0009] The overlap of the individual valve elements creates a labyrinth-like structure through which the gas must pass to escape from the gas bag through the outlet opening. The degree of overlap, the number, shape, and stiffness of the valve elements can be adjusted to control the gas flow rate and its pressure dependence.

[0010] Preferably, adjacent valve elements overlap both at their outer edge and at their surface portion and thus at least with a portion of their inner edge.

[0011] Apart from the valve elements, no other components are required for the valve, making it cost-effective and simple to manufacture. In particular, the valve has no tear seams or tension elements.

[0012] For example, gas bag fabric can be used for the valve elements. The individual valve element can consist of a single layer of fabric. To increase rigidity, the individual valve element can also consist of several identically shaped fabric layers that are superimposed and connected to each other, for example, by gluing, welding, or sewing.

[0013] The rigidity of the individual valve element can also be increased by using a coating.

[0014] Preferably, all valve elements of a valve are identically constructed and shaped.

[0015] The valve elements can be attached to the peripheral edge of the discharge opening along their entire outer edge.

[0016] In one variant, however, each valve element is only attached to the peripheral edge along a portion of its outer edge. This means that each valve element is also movable relative to the outer wall of the gas bag along at least a portion of its outer edge, allowing the valve element to open further outward relative to the area of ​​the discharge opening.

[0017] It is possible that the fixed section of the outer edge is located in the middle of the outer edge with respect to the circumference of the outflow opening and thus the valve element is movable on both sides of the fixed section relative to the circumferential edge of the opening.

[0018] The valve elements can be arranged to form an iris diaphragm arrangement in which the valve elements overlap one another in a scale-like or shingled manner along the peripheral edge of the discharge opening. The valve elements can move relative to each other to a certain extent, except for the sections of the outer edge that are fixed along the peripheral edge of the discharge opening.

[0019] Each valve element overlaps, for example, with exactly two adjacent valve elements, wherein preferably at least the majority of the valve elements are arranged one above the other in a scale-like or roof-tile manner along the peripheral edge of the discharge opening. Preferably, the section of the outer edge of the valve element that rests directly on the peripheral edge of the discharge opening is secured to the peripheral edge, while the section(s) of the outer edge that rest on another valve element remain unsecured.

[0020] A length of the partial section of the outer edge of the valve element fixed to the circumferential edge may be longer than a total length of the partial section(s) not fixed to the circumferential edge, for example twice as long.

[0021] The outer edge of each valve element can be longer than its inner edge.

[0022] For example, 2 to 15, in particular 2, 3, or 4, valve elements are arranged around the peripheral edge of the discharge opening. These designs have proven suitable for sealing the discharge opening essentially gas-tight at the desired internal pressures when the valve is closed and for allowing a sufficient amount of gas to escape when the valve is open.

[0023] Especially in the case of a circular outflow opening, the outer edge preferably extends in a circular arc over an angle of 30° to 270°, in particular over 120°, 135°, 150°, 165° or 270°.

[0024] The valve elements preferably have the shape of a circular segment, or, more generally, the shape of a segment of the cross-sectional area of ​​the discharge opening, even if this is not circular.

[0025] The inner edge of the valve elements, for example, runs in two sections that meet at a bend. If the outer edge's circumferential angle is less than 180°, the bend forms a point. If the circumferential angle is greater than 180°, the bend lies in a recess. The bend corresponds specifically to the point on the valve element that, in the case of a circular discharge opening, is radially closest to the center of the discharge opening.

[0026] In one variant, both sections of the inner edge run straight, which in the case of a circular segment-shaped valve element results in the inner edge sections lying along a radius of the outflow opening. In another variant, at least one of the sections of the inner edge runs concavely curved from the outer edge to the bend. The valve elements can, for example, be shaped and arranged such that there is a point on the surface of the outflow opening beyond which none of the surface sections protrudes radially. In the case of a circular outflow opening, this is preferably the center of the circle, which is only touched by all surface sections. All valve elements can then move most freely at the center of the surface of the outflow opening.

[0027] It is also conceivable to shape and arrange the valve elements in such a way that an area is provided at the center of the discharge opening surface that is not covered by any valve element, leaving a small area permanently available as a discharge opening. This can be advantageous, for example, to facilitate the discharge of gas from the airbag at the end of its intended service life.

[0028] According to another variant, all valve elements are connected to each other by a circumferential fixation in the surface sections. This fixation, which is usually a seam, restricts the movement of the valve elements perpendicular to the surface of the discharge opening and thus limits the gas escape. This design is therefore particularly suitable for higher intended internal pressures.

[0029] The fixation preferably runs concentrically to the edge of the outflow opening, preferably close to the center of the outflow opening, in order to be able to restrict the range of movement of the valve elements relatively strongly.

[0030] Particularly in this variant, it can also be advantageous if the valve elements have a bulge at their radially innermost point, where several valve elements overlap. This bulge can be used, for example, to secure the valve elements during the circumferential fixation, but also to increase the flow resistance in the area of ​​the center of the discharge opening.

[0031] According to a further aspect, in order to stiffen the respective valve element, the surface section of at least one valve element can have a fixed fold extending into the surface of the outflow opening.

[0032] For this purpose, it would also be conceivable to connect adjacent, superimposed surface sections in sections with a radially extending fixation. The invention is described in more detail below using several exemplary embodiments with reference to the accompanying figures. The figures show:

[0033] Figure 1 is a schematic representation of an airbag according to the invention with a valve according to a first variant;

[0034] Figure 2 is a schematic representation of the components of the valve of Figure 1;

[0035] Figure 3 is a schematic representation of a valve element of the valve of Figure 1;

[0036] Figure 4 is a further schematic representation of the valve from Figure 1;

[0037] Figure 5 is a schematic sectional view along the line VV of Figure 4;

[0038] Figure 6 is a schematic sectional view along the line VI-VI of Figure 4;

[0039] Figure 7 is a schematic representation of the components of a valve of an airbag according to the invention according to a second variant;

[0040] Figure 8 is a schematic representation of a valve with valve elements according to Figure 7;

[0041] Figure 9 is a schematic sectional view of the valve of Figure 8 along the line IX-IX;

[0042] Figure 10 is a schematic representation of a valve element of the valve of Figure 8;

[0043] Figure 11 is a schematic representation of the valve of Figure 8 from the opposite side;

[0044] Figure 12 is a schematic sectional view along the line Xll-Xll of Figure 11;

[0045] Figure 13 shows a schematic representation of a valve element of a valve of a gas bag according to the invention according to a further variant; Figure 14 shows a schematic representation of a valve using valve elements according to Figure 13;

[0046] Figure 15 is a schematic sectional view of the valve of Figure 14 along the line XV-XV of Figure 14;

[0047] Figure 16 is a schematic representation of a valve element of a valve of an airbag according to the invention according to a further variant;

[0048] Figure 17 is a schematic representation of a valve using valve elements according to Figure 16;

[0049] Figure 18 is a schematic sectional view of the valve of Figure 17 along the line XVI I l-XVI II of Figure 17;

[0050] Figure 19 is a schematic representation of the size ratios of the valve elements of a valve of a gas bag according to the invention;

[0051] Figure 20 is a schematic representation of an alternative form of a valve element of a valve of a gas bag according to the invention;

[0052] Figure 21 is a schematic representation of a valve element of a valve of an airbag according to the invention according to a further variant;

[0053] Figure 22 is a schematic representation of the valve using valve elements according to Figure 21;

[0054] Figure 23 is a schematic sectional view along the line XXI I l-XXI 11 of Figure 22;

[0055] Figure 24 is a schematic sectional view along the line XXI V-XXI V of Figure 22;

[0056] Figure 25 is a schematic representation of a valve element of a valve of an airbag according to the invention according to a further variant;

[0057] Figure 26 is a schematic representation of the valve using valve elements according to Figure 23; and

[0058] Figure 27 is a schematic sectional view taken along line XXVII-XXVII of Figure 26. Throughout the figures, identical reference numerals designate identical or substantially identical components and parts. For reasons of clarity, not all identical components are always provided with reference numerals.

[0059] Figure 1 shows a gas bag 10 (only schematically indicated) with an outer wall 12 having an outflow opening 14 through which gas can flow outward from an interior of the gas bag 10. A passive valve 16 is arranged at the outflow opening 14, which can close or open the outflow opening 14 with a variable gas flow rate.

[0060] The term "closing" here means that the gas flow through the outflow opening 14 is severely restricted and at least largely prevented by the valve 16, while the term "releasing" means that gas can flow out through the outflow opening 14 and the valve 16 with a sufficiently low flow resistance to allow a significant gas transport from the gas bag 10 into the environment. It is therefore not necessarily the case that no gas at all can escape from the gas bag when the valve 16 is closed, nor is it the case that the valve 16 no longer offers any flow resistance when it is open.

[0061] In the first variant shown in Figures 1 to 6, the valve 16 comprises exactly two flexible valve elements 18, both of which are arranged on a peripheral edge 20 of the outflow opening 14.

[0062] Both valve elements 18 are identically shaped and here have the shape of a circular segment, which in this variant extends over a circumferential angle a of 270°.

[0063] A circular outer edge 22 of the valve element 18, together with an inner edge 24, encloses a surface section 28. The inner edge 24 has two radially and rectilinearly extending sections 24a, 24b that meet at a bend 26 in the center of the circle. Since the circumferential angle a is greater than 180°, the two inner edge sections 24a, 24b define a recess 30.

[0064] The two valve elements 18 are placed on the surface of the discharge opening 14 such that the outer edge 22 runs along the peripheral edge 20 of the discharge opening 14. The valve elements 18 are positioned such that they are arranged mirror-symmetrically with respect to their inner edges 24, i.e., the recess 30 in both valve elements 18 is offset by 180°. One of the valve elements 18 is placed over the other valve element 18. Due to the shape of the valve elements 18, both the outer edges 22 and the surface sections 28 overlap in sections, but not the recesses 30.

[0065] The outer edge 22 of each valve element 18 is secured to the peripheral edge 20 of the discharge opening 14 by a fixation 31, in these examples by a seam (illustrated, for example, in Figures 5 and 6). A connection by other suitable means, in particular gluing or welding, would of course also be possible.

[0066] The valve elements 18 are either fixed along their entire outer edge 22 to the peripheral edge 20 of the outflow opening 14 (see Figures 3 to 6), or only a partial section 32 of the outer edge 22 is fastened to the peripheral edge 20 (see Figures 1 and 2).

[0067] In the latter embodiment, the fixed portion 32 of the outer edge 22 is the area of ​​the outer edge 22 that is not covered by the other valve element 18. This corresponds to the central 90° portion of the outer edge 22, as can be seen in Figures 1 and 2. The overlapping portions 34, 36, hereinafter also referred to as the first and second circumferential ends, are indicated by dotted lines in Figure 2.

[0068] In this variant, the valve elements 18 are neither fixed directly to the outer wall 12 of the gas bag 10 nor to each other in the sections 34, 36 in which they overlap.

[0069] Here, the sections 34, 36 of one valve element 18 both rest on the other valve element 18. However, it would also be possible to place the two valve elements 18 one inside the other in such a way that one of the sections 34, 36 rests on top of the other valve element 18 and the other section 36, 34 rests under the other valve element 18.

[0070] Up to a certain value of the internal pressure in the gas bag 10, the mechanical resistance of the valve elements 18 is so high that essentially no gas flows out of the gas bag 10. If this internal pressure value is exceeded, however, the forces acting outward on the valve elements 18 are high enough to partially push the valve elements 18 outwards, creating a labyrinth-like flow path from the interior of the gas bag 10 between the individual valve elements 18 to the outside, through which gas can flow out of the gas bag 10. If the internal pressure in the gas bag 10 drops again, the valve elements 18 rest against one another again, thus closing the outlet opening 14 again.

[0071] The valve 16 is thus designed to be purely passive and is opened and closed exclusively by the current internal pressure of the gas bag 10, whereby the degree of opening also depends on the internal pressure.

[0072] In all variants described in this application, it is possible to fix the outer edge 22 all the way around or only in sections to the peripheral edge 20.

[0073] The functionality of valve 16 is the same for all variants.

[0074] Figures 7 to 12 show a valve 16 in a second variant.

[0075] The general structure, the functional principle and the arrangement of the valve elements 18 around the outflow opening 14 are analogous to the first variant described above.

[0076] In contrast to the first variant, there are a total of four valve elements 18. These are also designed as circular segments, but with a circumferential angle a of 135°.

[0077] Since the circumferential angle a is less than 180°, the bend 26 forms a point at which the two inner edge sections 24a, 24b meet.

[0078] The four valve elements 18 are superimposed along the circumferential edge 20 of the outflow opening 14 in a scale-like or roof-tile manner, resulting in an iris diaphragm arrangement. Each valve element 18 overlaps the two adjacent valve elements 18 at its outer edge 22 with its surface section 28 for a total of approximately two-thirds of its length, with a first circumferential end at section 34 lying on a second circumferential end at section 36 of the adjacent valve element 18 on one side, and the second circumferential end at section 36 lying below the first circumferential end at section 34 of the adjacent valve element 18 on the other side. This is also outlined in the sectional view in Figure 9.

[0079] Sections 34, 36 are marked with dashed lines in Figure 7.

[0080] To manufacture the valve 16, all valve elements 18 are placed one above the other in the desired arrangement along the peripheral edge 20 of the outflow opening 14 and then connected to the outer wall 12 of the gas bag 10 by means of the fixing means 31.

[0081] In this variant too, all valve elements 18 are each fastened to the peripheral edge 20 of the outflow opening 14 by only a partial section 32, which here also corresponds to the section of the outer edge 22 which is not covered by any of the adjacent valve elements 18, i.e. outside the sections 34, 36.

[0082] Due to the smaller circumferential angle a, the bend 26, in which the two sections of the inner edge 24 meet, does not form a recess, but rather a tip, which here lies in the center point M of the surface of the outflow opening 14.

[0083] All valve elements 18 are arranged such that they do not overlap or only slightly overlap in the area of ​​the bend 26.

[0084] In Figures 10 to 12, the fixing means 31 is formed circumferentially around the entire circumferential edge 20 of the outflow opening, so that the valve elements 18 are connected along their entire outer edge 22 to the circumferential edge 20 of the outflow opening 14 and the fixing means 31 encompasses all of the valve elements 18 lying one above the other.

[0085] In the variant shown in Figures 13 to 15, four valve elements 18 are present with a circumferential angle a of 120°, while the valve 16 of the variant shown in Figures 16 to 18 has four valve elements 18 with a circumferential angle a of 150°. The different circumferential angle a is the only difference compared to the variant shown in Figures 10 to 12. The dimensions of the valve elements 18 are selected here such that the valve elements 18 completely cover the area of ​​the discharge opening 14.

[0086] For circular segment-shaped valve elements 18, in which the two sections 24a, 24b of the inner edge 24 each correspond to the radius of the circle, these should be slightly longer than the radius of the discharge opening 14, so that the outer edge 22 of the valve elements 18 can be fixed concentrically to the center point M of the discharge opening 14 along the peripheral edge 20 with sufficient spacing. The inner edge sections 24a, 24b should therefore have a length D that is greater than half the diameter d of the discharge opening 14. This is sketched in Figure 19.

[0087] Of course, it is also possible to use differently shaped valve elements 18, for example, in a crescent shape, as shown in Figure 20. In this case, the outer edge 22 follows a circular arc, while at least one of the inner edge sections 24a, 24b is concave. Overall, the surface area of ​​the surface section 28 is thus reduced compared to the other variants shown, which reduces the opening resistance of the valve 16.

[0088] Just as the exact number of valve elements 18, the specific shape of the valve elements 18 is at the discretion of the person skilled in the art.

[0089] Another variant is shown in Figures 21 to 24.

[0090] Here, too, there are four individual valve elements 18, which are arranged along the peripheral edge 20 of the outflow opening 14 in a manner analogous to the variants described above.

[0091] However, here each of the valve elements 18 is folded inward, as shown in Figures 11 and 13, forming an S-shaped fold 40 starting from the crease 26, extending to the outer edge 22 and in which the valve element 18 is folded along radial fold lines 41. The fold 40 is permanently secured in itself by a fixation 42, here a seam.

[0092] Overall, this again creates a valve element 18 with a circumferential angle a of 135° (other circumferential angle dimensions are of course also feasible), which is, however, stiffened by the fold 40 in its surface section 28.

[0093] The valve elements 18 thus prefabricated are arranged and fixed in the same way as those of the previous variant.

[0094] Figures 25 to 27 show yet another variant of a valve 16. As in previous variants, four valve elements 18 are provided in the form of a circular segment with a circumferential angle a of 135°.

[0095] Here, the surface section 28 forms a small bulge 44 in the area of ​​the bend 26, where the two sections 24a, 24b of the inner edge 24 meet.

[0096] When the valve elements 18 are placed one above the other in the desired arrangement along the peripheral edge 20 of the outflow opening 14, all bulges 44 of all valve elements 18 overlap in the region of the center point M of the outflow opening 14 (see Figures 26 and 27).

[0097] A fixation 46, here a seam, is formed around the bulge 44, which secures the adjacent valve elements 18 to one another. The fixation 46 is arranged here in the immediate vicinity of the center point M of the discharge opening 14, but could also be offset further toward the peripheral edge 20 of the discharge opening.

[0098] In this variant too, the outer edge 22 of all valve elements 18 is fixed circumferentially along the peripheral edge 20 of the outflow opening 14.

[0099] A fabric, in particular a gas bag fabric, is used as the material for the valve elements 18. The valve element 18 consists of a single fabric layer or of several superimposed fabric layers. Optionally, the fabric can be provided with a coating. The number of fabric layers used and / or the coating determines the stiffness of the valve element 18 and thus influences the flow resistance of the valve 16. All variants of the valves 16 discussed here have this structure.

[0100] In all variants described here, all valve elements 18 of a valve 16 are always identically shaped and constructed. The invention is described here for a circular discharge opening 14. Accordingly, the valve elements 18 are also designed as circular segments. Of course, the invention is also transferable to other cross-sectional shapes of the discharge opening 14, for example, elliptical openings. In this case, the valve elements 18 should be analogously generally shaped as segments of the cross-sectional area that extend over a suitable circumferential angle α.

[0101] All features of the individual variants can be freely interchanged or combined with one another at the discretion of the person skilled in the art. In particular, the outer edge 22 of the valve elements 18 can be fixed over its entire length or only over a partial section 32 along the circumferential edge 20 of the outflow opening 14. The use of folds 40 in the surface section of the individual valve elements 18 is also conceivable for any desired shape and circumferential angle α of the valve elements 18. It is equally possible to use a central bulge 44 for valve elements 18 with any desired circumferential angle α. Optionally, valve elements 18 with and without fold 40 and / or bulge 44 can also be combined in one valve 16. It would also be conceivable to use valve elements 18 with different circumferential angles α in one valve 16.

Claims

Patent claims 1 . A gas bag with an outflow opening (14) in an outer wall (12) which is covered by a valve (16), wherein the valve (16) comprises at least two flexible valve elements (18) which are arranged next to one another along a peripheral edge (20) of the outflow opening (14), wherein each valve element (18) has an outer edge (22) which is arranged on the peripheral edge (20) of the outflow opening (14) and is fixed there at least in sections, and each valve element (18) has a surface section (28) which extends from the peripheral edge (20) into the surface of the outflow opening (14) and ends in an inner edge (24) in the region of the outflow opening (14), wherein the surface sections (28) are at least partially unfixed to one another in the region of the outflow opening (14) and the surface sections (28) are movable perpendicular to the surface of the outflow opening (14), so that the outflow opening (14) has a variable gas flow,and wherein the surface sections (28) of adjacent valve elements (18) overlap in sections., 2. Gas bag according to claim 1, wherein each valve element (18) is attached to the peripheral edge (20) only along a partial section (32) of its outer edge (22).

3. Gas bag according to claim 2, wherein each valve element (18) overlaps with exactly two adjacent valve elements (18).

4. Gas bag according to one of claims 2 and 3, wherein a length of the partial section (32) of the outer edge (22) of the valve element (18) fixed to the peripheral edge (20) can be longer than a total length of the partial section(s) of the outer edge (22) not fixed to the peripheral edge (20), in particular twice as long.

5. Gas bag according to one of the preceding claims, wherein 2 to 15, in particular 2, 3 or 4, valve elements (18) are arranged around the peripheral edge (20) of the outflow opening (14).

6. Gas bag according to one of the preceding claims, wherein the outer edge (22) extends over an angle of 30° to 270°, in particular 120°, 135°, 150°, 165° or 270°.

7. Gas bag according to one of the preceding claims, wherein the valve elements (18) have the shape of a circular segment and / or and together form an iris diaphragm arrangement.

8. Gas bag according to one of the preceding claims, wherein the valve elements (18) are shaped and arranged such that there is a point (M) on the surface of the outflow opening (14) beyond which none of the surface sections (28) protrudes radially.

9. Gas bag according to one of the preceding claims, wherein all valve elements (18) are connected by a circumferential fixing (46) in the surface sections (28).

10. Gas bag according to one of the preceding claims, wherein the surface section (28) of at least one valve element (18) has a fixed fold (40) extending into the surface of the outflow opening (14).

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