Dual-chamber airbag with asymmetrically adjustable parameters

Abstract

Vehicle airbag assembly (100) comprising: an airbag (102) comprising a first chamber (104) and a second chamber (106), the first chamber (104) having a larger volume than the second chamber (106) in an inflated state of the airbag (102); a first internal vent opening (116) allowing gas to enter the first chamber (104); and a second internal vent opening (118) allowing gas entry into the second chamber (106), the first internal vent opening (116) being configured for a greater gas flow than the second internal vent opening (118); and one or more inner straps (130,132) coupled to the second chamber (106) to limit the depth of the second chamber (106) in the inflated state, further comprising: a gas inlet (110) arranged on an outer wall of the airbag (102) for inflating the airbag (102); and an internal passage (114) connecting the gas inlet (110) to the first internal vent opening (116) and the second internal vent opening (118), further comprising a plurality of deflection elements (124, 126, 128) defining at least one inner wall of the first chamber (104) and at least one inner wall of the second chamber (106), wherein the first internal vent opening (116) is formed by a first gap between a first deflection element (124) and a second deflection element (126) of the plurality of deflection elements (124, 126, 128), and the second Internal vent opening (118) is formed by a second gap between the first deflection element (124) and a third deflection element (128) of the plurality of deflection elements (124, 126, 128), characterized in that the height of the third deflection element (128) is greater than the height of the second deflection element (126).

Description

FIELD OF TECHNOLOGY

[0001] This application generally concerns supplementary restraint systems in a motor vehicle and, in particular, dual-chamber knee airbags with asymmetrically adjustable design parameters. BACKGROUND

[0002] Most motor vehicles include some type of supplemental restraint system, such as an inflatable airbag, that supplements the vehicle's seatbelt system to enhance the protection of a vehicle occupant during a loading event (e.g., vehicle impact or collision). For example, a typical frontal impact causes forward movement of the occupant (e.g., driver or front passenger) toward a dashboard (or instrument panel), glove compartment (or glove box), or other vehicle panel. Accordingly, the supplemental restraint system may include one or more airbags that deploy in front of the vehicle occupant to substantially prevent the occupant from impacting the vehicle's front panel(s).

[0003] One type of frontal airbag is a knee airbag, which inflates in front of the occupant's lower legs and / or knees to help prevent impact with lower portions of the vehicle's panels. Many knee airbags contain a single internal chamber that expands laterally upon inflating to protect both occupant's legs evenly. However, such knee airbags typically do not account for loading events that occur off-center or at an angle to a vehicle's direction of motion (such as an offset impact, a small offset rigid obstacle (SORB) impact, an angled impact, etc.), and therefore cause sideways movement of the occupant within the vehicle compartment, e.g., toward a vehicle door or center console, in addition to forward movement.Furthermore, many existing knee airbags do not take into account other forms of uneven interference or load distribution of the occupant's knees and / or legs during an impact, e.g., due to an uneven engine compartment within the vehicle, a bulge of a lower portion of the instrument panel or glove box (e.g., in the area adjacent to the occupant's knees or legs), or stiffness differences between the instrument panel, glove box, center console, or other vehicle panels.

[0004] For example, an existing knee airbag has a non-symmetrical single-chamber design, featuring a widened, thicker section at the end of the airbag facing an outboard side of the vehicle, thus restricting both sideways and forward movement of the occupant during a loading event. The front or main section of the airbag has a uniform thickness and stiffness, which, however, does not account for uneven interference with the vehicle compartment, which can affect the load distribution on at least one front side of the knees and / or legs or the amount of energy expected to be absorbed by the various contact areas.

[0005] The document US 2002 / 0 171 232 A1 discloses a leg protection device for protecting the legs of a vehicle occupant from a vehicle element, which comprises a gas generator for generating gas and an airbag, wherein the airbag is attached to the gas generator and comprises a first chamber with a first gas inlet and a second chamber with a second gas inlet, so that it expands outside and along the vehicle element when inflated.

[0006] The document DE 101 64 519 A1 discloses an airbag arrangement in which a gas generator is arranged in a flexible chamber within a gas bag, wherein the gas for inflating the gas bag is guided through the flexible chamber into the gas bag.

[0007] Other existing knee airbags feature multi-chamber designs with non-uniform volumes, air pressures, or inflation timing to vary the protection of different knee and / or leg areas. However, the overall shape, volume, and stiffness of each chamber in such knee airbags cannot be individually or asymmetrically tuned to account for, for example, the geometry of the various panels in the vehicle compartment or the amount of energy expected to be absorbed in the event of contact between an occupant and the chamber.

[0008] Accordingly, there is a need for an improved knee airbag that can be asymmetrically configured consistent with uneven airbag engagements, including vehicle compartment geometry, to provide appropriate load distribution to each knee and / or leg of the vehicle occupant in various types of impacts (e.g., frontal impact, offset impact, angle impact). SUMMARY

[0009] The invention seeks to overcome the above-mentioned problems by providing systems for a dual-chamber knee airbag with design parameters that can be tuned asymmetrically with respect to each chamber, thereby providing an airbag that can be individually adjusted according to a geometry of the vehicle compartment and other factors that may contribute to uneven engagement of the airbag.

[0010] The object is achieved with a vehicle airbag arrangement having the features of independent patent claim 1. Advantageous embodiments can be found in the dependent claims.

[0011] For example, one embodiment provides a vehicle airbag assembly including an airbag having a first chamber and a second chamber, the first chamber having a larger volume than the second chamber in an inflated state of the airbag; a first internal vent opening allowing gas entry into the first chamber; and a second internal vent opening allowing gas entry into the second chamber, the first internal vent opening configured for a larger gas flow rate than the second internal vent opening.

[0012] Another exemplary embodiment provides a vehicle airbag assembly including an airbag having a first chamber and a second chamber and at least one inner strap coupled to the second chamber to restrict an inflation depth of the second chamber, the first chamber having an unrestricted depth and a volume greater than a volume of the second chamber in an inflated state of the airbag.

[0013] A method not encompassed by the invention includes forming a first airbag chamber having a first width selected according to a vehicle exterior configuration; forming a second airbag chamber having a second width selected according to a vehicle interior configuration; forming a first vent opening to permit a first gas flow into the first airbag chamber; and forming a second vent opening to permit a second gas flow into the second airbag chamber.

[0014] As will be appreciated, this disclosure is defined by the appended claims. The description summarizes aspects of the embodiments and should not be used to limit the claims. Further implementations are contemplated in accordance with the techniques described herein, as will be apparent to those skilled in the art upon examination of the following drawings and detailed composition, and these implementations are within the scope of this application. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] For a better understanding of the invention, reference may be made to the embodiments shown in the following drawings. The components of the drawings are not necessarily to scale, and related elements may be omitted, or in some cases, proportions may be exaggerated, in order to emphasize and clearly illustrate the novel features described herein. Furthermore, system components may be arranged in a variety of ways, as is known in the art. Furthermore, like reference numerals may designate corresponding parts throughout the different views. Fig. 1 is a side view of an exemplary vehicle with an exemplary knee airbag in an inflated state according to certain embodiments. Fig. 2 is a rear perspective view of an exemplary airbag assembly as shown in Fig. 1, according to certain embodiments. Fig. 3 is a cross-sectional view of an exemplary airbag assembly according to certain embodiments. Fig. 4 is a side view of an exemplary chamber in the airbag assembly of Fig. 3 according to certain embodiments. Fig. 5 is a side view of another exemplary chamber in the airbag assembly of Fig. 3 according to certain embodiments. Fig. 6 is a flowchart of an exemplary method for manufacturing a vehicle airbag according to certain embodiments. DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

[0016] While the invention may be embodied in different forms, there are shown in the drawings and described below some exemplary and non-limiting embodiments, it being understood that the present disclosure is to be considered as illustrative of the invention and not as limiting the invention to the specific embodiments shown.

[0017] In this application, the use of the disjunctive form is intended to include the conjunctive form. The use of definite and indefinite articles is not to be understood as cardinality. In particular, a reference to "the" object or "an" object is also to be understood as referring to one of a possible plurality of such objects.

[0018] Fig. 1 shows an exemplary vehicle 10 that includes a cabin area 12 configured to accommodate at least one front seat occupant 14 in a front seat 16. The illustration of the embodiment shows a driver side of the vehicle 10, wherein the front seat occupant 14 is a driver of the vehicle 10 and the front seat 16 is a driver seat. Although not shown, the cabin area 12 (or passenger compartment) may also include a front seat on a passenger side of the vehicle 10, as well as, in some cases, one or more rear passenger seats or rows of seats. While the vehicle 10 is Fig. 1 as a sedan or coupe, it should be understood that the vehicle 10 may be any type of motor vehicle, including, but not limited to, a sport utility vehicle (SUV), a minivan, a van, a truck, a station wagon, etc. Furthermore, while the vehicle 10 is shown as a left-hand drive vehicle, in other embodiments the vehicle 10 may be a right-hand drive vehicle.

[0019] As shown, the cabin area 12 includes a knee airbag 18 deployed from a lower portion of an instrument panel 20 (also referred to as an instrument panel) of the vehicle 10. As also shown in Fig. 2, the knee airbag 18 is configured to contact lower regions (e.g., knees and / or lower legs) of the front seat occupant 14 when in a fully deployed or inflated state. The cabin area 12 may further include other supplemental restraint system (SRS) devices, such as a driver airbag 19 deployable from a steering wheel 22 mounted on a steering column 24, and / or a side impact airbag (not shown) deployable from a vehicle door or other panel on an outboard side 26 of the vehicle 10. Although the knee airbag 18 is shown on the driver's side of the cabin compartment 12, it should be understood that the knee airbag 18 may also be installed on the passenger side of the vehicle 10 (e.g., deployed from a lower portion of a glove box of the vehicle 10) and / or in front of one or more rear passenger seats.The airbag 18 may be made or formed from a material suitable for use in airbags.

[0020] Although not shown, the outboard side 26 may include one or more vehicle doors, one or more vehicle pillars, and / or any other panels located on the exterior sides of the vehicle 10. The vehicle 10 may further include an inboard side 28, which includes a center console (not shown) and other interior panels of the vehicle 10. In some cases, the instrument panel 20 may include the steering column 24 and / or the steering wheel 22 extending therefrom, in addition to the instrument panel or instrument cluster positioned behind the steering column 24. Also, in some cases, the glove box may be considered an extension of the instrument panel 20 or coupled to a portion of the instrument panel 20 that extends into the passenger side of the vehicle 10. Therefore, the term "instrument panel," as used herein, may refer to any combination of these vehicle components.

[0021] In certain frontal loading events (e.g., angled impact, offset impact, SORB impact, etc.), an impact angle relative to the direction of travel of the vehicle 10 may cause uneven engagement with the cabin area 12, which may cause forward movement of the front seat occupant 14 toward the instrument panel 20 as well as sideways movement of the occupant 14 toward, for example, the outboard side 26 or the inboard side 28. In some cases, the loading event may also cause rearward and / or sideways movement of the instrument panel 20 or other panels of the vehicle 10 (e.g., the steering column 24, the steering wheel 22, outboard side panels, inboard side panels, etc.).Engagement with the cabin area 12 may also be uneven due to interior areas of the vehicle 10, including, but not limited to, an irregular engine compartment enclosure, a stiffness of the materials used for various panels in the cabin area 12, and a configuration of the panels in the cabin area 12, such as a geometry of the lower portion of the instrument panel 20 (or, in the case of a passenger side airbag, the lower portion of the glove box), a geometry of the outboard side 26 (e.g., geometries of the vehicle door, pillar(s), and other other exterior side panels), a geometry of the inboard side 28 (e.g., geometries of the center console and other other interior side panels), and the like. For example, as shown in FIG. Fig. 1, the lower portion of the instrument panel 20 may sweep away from the steering column 24 and toward the vehicle floor 10, and an angle of this sweep, as well as any protrusions or recesses therein, may cause the lower legs of the occupant 14 to impact the instrument panel 20 unevenly in a loading event.

[0022] Such uneven engagements may impose different loads on the left or right knee or leg of the occupant 14 upon contact with the knee airbag 18. For example, on the driver side, the left side (LHS) load may be greater than the right side (RHS) load, while on the passenger side, the RHS load may be greater than the LHS load, due at least in part to the different geometry and stiffness of the instrument panel 20 and the glove box, and in some cases, those of the inboard and / or outboard panels. Embodiments of the knee airbag 18 are configured to distribute the LHS and RHS loads more evenly, thereby helping to impose a lower peak load on the legs of the occupant 14, respectively. As discussed further below with respect to Fig. 3 to 6, the knee airbag 18 can achieve even more even load distribution by utilizing two asymmetrically configured chambers (e.g., an LHS chamber and an RHS chamber), each chamber being individually tuned based on the stiffness and / or configuration of the one or more vehicle panels that may contact the chamber upon deployment of the airbag 18.

[0023] In relation to Fig. 3 is a cross-sectional view of an exemplary vehicle airbag assembly 100 according to embodiments, including a dual-chamber airbag 102 (or airbag cushion) configured to include a first chamber 104 and a second chamber 106. In a preferred embodiment, the airbag assembly 100 is shown in Fig. 1 and Fig. 2. In further embodiments, the airbag assembly 100 may be included in another inflatable supplemental restraint system device, such as a side impact airbag or other airbag device designed for a different location on the vehicle 10. When not in use, the airbag assembly 100 may be stored in a deflated or at least partially deflated state in a dedicated vehicle panel (e.g., in a lower portion of the instrument panel or glove compartment). If a load event is detected, the airbag assembly 100 (e.g., as shown in Fig. 1 and Fig. 2) be inflated to a deployed condition by introducing a sufficient amount of gas 108 (or inflation fluid) through a gas inlet 110 on an outer wall 112 of the airbag 102 and / or the airbag assembly 100.

[0024] As shown, the gas 108 (or inflation gas) may be introduced into the airbag 102 at the gas inlet 110, flow through an interior passage 114 of the airbag 102, and then into each of the first and second chambers 104, 106. The interior passage 114 may be formed between the first and second chambers 104, 106 and connected to the gas inlet 110 at an inlet end of the passage 114, as shown. The airbag assembly 100 includes a first internal vent opening 116 for allowing gas entry into the first chamber 104 and a second, opposite internal vent opening 118 for allowing gas entry into the second chamber 106. Each of the vent openings 116, 118 may be connected to the passage 114 at a distal or an inner end of the passage 114 that is opposite the gas inlet 110.

[0025] As in Fig. 3, the two chambers 104 and 106 are positioned side by side or parallel to each other and configured to each contact a knee or other leg area of ​​a vehicle occupant (e.g., the front seat occupant 14) at contact points 120, 122, respectively, when deployed. In embodiments, the first chamber 104 is configured to support a greater load than the second chamber 106 and may therefore be located toward a side of the vehicle (e.g., outboard side or inboard side) where structural compromises are greater, a greater concentration of critical locations exists, or a generally greater amount of input energy is expected. For example, in a typical vehicle impact, a greater amount of incoming energy may be expected on the outboard sides of the vehicle, while a lesser amount of incoming energy may be expected on the inboard sides.Accordingly, the in . Fig. 3 shown airbag arrangement 100 on a driver side of a left-hand drive vehicle (e.g. the vehicle in Fig. 1) or on a passenger side of a right-hand drive vehicle such that the first chamber 104 is positioned toward the outboard side 26 to receive the left knee of the front seat occupant 14 at the contact point 120 and the second chamber 106 is positioned toward the inboard side 28 to receive the right knee of the front seat occupant 14 at the contact point 122.

[0026] As can be seen, in order to configure the airbag assembly 100 for installation, for example, on the passenger front side of the left-hand drive vehicle or the driver side of a right-hand drive vehicle, the airbag assembly 100 only needs to be turned over or inverted to form a mirror image of the Fig. 3. In these cases, the second chamber 106 may be placed on the left side of the airbag 102 to accommodate the left knee of the front seat passenger 14 at the contact point 122, and the first chamber 104 may be placed on the right side of the airbag 102 to accommodate the right knee of the front seat passenger 14 at the contact point 120.

[0027] In order for the first chamber 104 to support a greater load or absorb more energy than the second chamber 106, according to embodiments, the first chamber 104 is generally configured to have a larger volume and / or greater stiffness than the second chamber 106. The exact configuration or geometry of each of the chambers 110 and 112, as well as the overall airbag assembly 100, may be specifically configured to accommodate a cabin configuration of the vehicle and / or a placement of the airbag assembly 100 within the vehicle (e.g., LHS or RHS). In particular, the airbag assembly 100 is arranged to provide a variety of design parameters, which may be tuned asymmetrically, e.g., by an airbag manufacturer, so that each of the chambers 104 and 106 has an appropriate or required amount of volume, stiffness, size, or area (e.g., length, width, depth, etc.).) and / or energy absorption to protect the particular knee or leg area it touches.

[0028] In embodiments, the design parameters are based, at least in part, on the arrangement of one or more internal deflection elements (e.g., deflection elements 124, 126 and 128 in Fig. 3) in the airbag 102 between the first chamber 104 and the second chamber 106. The baffles may be configured to (i) form a barrier or seal between the chambers 104 and 106 to substantially prevent the passage of the inflation gas 108 through the interior walls of the chambers 104 and 106, and (ii) form the vent openings 116 and 118 and the passage 114, respectively, allowing gas entry into the chambers 104 and 106, for example, as described in more detail below. In embodiments, the baffles define each of the chambers 104 and 106 by forming at least one interior wall of the first chamber 104 and at least one interior wall of the second chamber 106. The deflection elements may be inert sections of the airbag 102 that are not inflated when the gas 108 is introduced into the interior passage 114.For example, the deflection elements may be formed in the material of the airbag 102 by stapling, adhering, or otherwise sealing together the portions of the airbag material intended to serve as deflection elements. While a specific embodiment of the deflection elements is described below and illustrated in FIG. Fig. 3, but it will be appreciated that other techniques may be used to form a tunable vented barrier between the first and second chambers 104 and 106 in accordance with the principles disclosed herein.

[0029] Back to Fig. 3, the airbag assembly 100 includes a first baffle 124 configured to form a barrier between an upper region of the first chamber 104 and an upper region of the second chamber 106. As shown, a first wall of the first baffle 124 defines an upper interior wall of the first chamber 104, and a second, opposite wall of the first baffle 124 defines an upper interior wall of the second chamber 106. The airbag assembly 100 further includes a second baffle 126 configured to define a lower interior wall of the first chamber 104 and to form a barrier between a lower region of the first chamber 104 and the interior passage 114. The airbag assembly 100 further includes a third deflection element 128 configured to define a lower interior wall of the second chamber 106 and to form a barrier between a lower region of the second chamber 106 and the interior passage 114. As shown in Fig. 3, a length of the inner passage 114 may be defined or formed between opposing outer walls of the second and third baffles 126 and 128, and the distal end of the passage 114 may be defined by the side wall of the first baffle 124.

[0030] As in Fig. 3, the first chamber 104 has a length L1, measured from an outer sidewall of the chamber 104 to one of the inner walls formed by the first baffle 124 and the second baffle 126. Similarly, the second chamber 106 has a width L2, measured from an opposite outer sidewall of the chamber 106 to one of the inner walls formed by the first baffle 124 and the second baffle 126. In embodiments, each of the widths L1 and L2 can serve as an individually tunable design parameter to achieve a desired volume, size, and / or area coverage for the chambers 104 and 106, respectively. In a preferred embodiment, the width L1 is configured to be greater than the width L2, such that the size and volume of the first chamber 104 is greater than that of the second chamber 106.In further embodiments, width L1 may be equal to width L2, and other design parameters may be configured to achieve a larger volume for the first chamber 104. In some cases, width L1 may be selected to provide appropriate surface coverage of a portion of the instrument panel located toward an outboard side of the vehicle and any other nearby vehicle panels. Likewise, width L2 may be selected to provide appropriate surface coverage of a portion of the instrument panel located toward an inboard side of the vehicle and any other nearby vehicle panels.

[0031] Another tunable design parameter may be the width of the interior passage 114. For example, the width of the passage 114 may be selected to provide an amount of gas pressure sufficient or necessary to inflate the first and second chambers 104 and 106. The width of the passage 114 may further be selected to provide an amount of gas flowing into each of the vents 116 and 118 necessary to maintain a desired stiffness in the chambers 104 and 106. The desired stiffness for each of the chambers 104, 106 may be determined, for example, based on the stiffness of the vehicle panels adjacent to the chamber 104, 106 and / or an amount of energy expected to be absorbed by the chamber 104, 106.

[0032] In the illustrated embodiment, each of the deflection elements 124, 126, and 128 has a width k1, k2, and k3, respectively, which may also serve as tunable design parameters. In some embodiments, the widths k1, k2, and k3 may be tuned to adjust the width L1 of the first chamber 104, the width L2 of the second chamber 106, and / or the width of the interior passage 114 therebetween, e.g., when the overall dimensions (e.g., overall width) of the airbag 102 are fixed. As shown in Fig. 3, a total width of the airbag 102 may be equal to the sum of the width L1 of the first chamber 104, the width k1 of the first deflection element 124, and the width L2 of the second chamber 106. Further, the width k1 of the first deflection element 124 may be equal to the sum of the width k2 of the second deflection element 126, the width of the interior passage 114, and the width k3 of the third deflection element 128. Accordingly, respective adjustments of the widths k1, k2, and k3 may affect a total volume and / or stiffness of each of the chambers 104 and 106, as well as an amount of gas and pressure introduced into the airbag 102 via the interior passage 114.

[0033] In embodiments, the vent openings 116 and 118 may be formed by the deflection elements 124, 126 and 128. For example, as in Fig. 3, the second and third baffles 126 and 128 are positioned substantially parallel to each other and configured to project substantially perpendicularly from a sidewall of the first baffle 124, but not extend completely to the sidewall. A remaining space or gap between the sidewall of the baffle 124 and each protruding end of the baffles 126 and 128 may form or provide the respective vent openings 116 and 118. In embodiments, the height of each of the baffles 124, 126, and 128 may be used as a design parameter to select a desired height d1 for the first vent opening 116 and a desired height d2 for the second vent opening 118.The resulting heights d1 and d2 can serve as design parameters for determining the amount of gas flowing through each of the vents 116 and 118, and thereby the stiffness of each of the chambers 104 and 106 upon deployment. In a preferred embodiment, the height d1 of the first vent 116 is configured to be greater than the height d2 of the second vent 118, such that more of the inflation gas 108 flows into or enters the first chamber 104 than the second chamber 106, and such that the first chamber 104 has a greater stiffness than the second chamber 106. In further embodiments, the height d1 may be equal to the height d2, and further design parameters may be configured to achieve greater stiffness in the first chamber 104.

[0034] In embodiments, the airbag assembly 100 may include one or more internal straps (also referred to as buffers or plates) coupled to the front and rear walls of the second chamber 106 to limit a depth or thickness of the second chamber 106 relative to the first chamber 104, thereby reducing the volume of the second chamber 106 and the amount of inflowing gas required to inflate the second chamber 106. For example, in Fig. 3, the second chamber 106 includes a first belt 130 and a second belt 132 positioned parallel to each other and coupled on one side to the first and third deflection elements 124 and 128, respectively. In a preferred embodiment, each of the belts 130 and 132 has a width B1 and B2 that is smaller than the width L2 of the second chamber 106, such that the belts 130 and 132 do not extend across the entire chamber 106. In further embodiments, the widths B1 and B2 may be equal to the width L2. The belts 130 and 132 serve to reduce the depth of the second chamber 106 relative to the depth of the first chamber 104, so that the first chamber 10 can provide fuller or deeper area coverage. For example, the first chamber 104 may require more stiffness, volume, or depth to protect the occupant from impact with the vehicle's exterior panels.

[0035] In embodiments, the widths B1 and B2 may serve as tunable design parameters for adjusting the volume and / or stiffness of the second chamber 106 when inflated. For example, larger B1 and B2 values ​​may result in a smaller overall volume and / or lower stiffness for the second chamber 106 and cause more of the inflation gas 108 to be forced into the first chamber 104. In embodiments, the values ​​for the widths B1 and B2 may be selected based on the configuration or geometry of the instrument panel (e.g., the portion of the instrument panel 20 disposed toward the inboard side 28) and interior side panels (e.g., the center console) of the vehicle.

[0036] With reference to Fig. 4 and Fig. 5 shows Fig. 4 is an exemplary side view of the first chamber 104 of the airbag assembly 100 in an inflated state, and Fig. 5 is an exemplary side view of the second chamber 106 of the airbag assembly 100 in an inflated state, but with the first chamber 104 not shown for clarity. As in Fig. 4, the first chamber 104 can be inflated to an unrestricted or full depth because the first chamber 104 does not include any straps or buffers. As shown in Fig. 5, because the second chamber 106 includes the chords 130 and 132, the second chamber 106 has a restricted depth, at least where the chords 130 and 132 are coupled to the front and rear walls of the second chamber 106. In some cases, the design parameter values ​​for the first and second chambers 104 and 106 may be substantially equivalent (e.g., same L1 and L2 values, same d1 and d2 values), except for the presence of the chords 130, 132 in the second chamber 106. In such cases, the chords 130 and 132 serve to reduce the volume and depth of the second chamber 106 compared to those of the first chamber 104. Furthermore, the parameters of B1 and B2 may be adjusted to achieve a desired volume and / or stiffness for the second chamber 106.

[0037] Fig. 6 illustrates an exemplary method 600 for manufacturing a vehicle airbag according to embodiments. Method 600 may be used to manufacture a knee airbag (such as airbag assembly 100) specifically tailored to the configuration of the vehicle cabin in which the airbag is to be installed.

[0038] The method 600 may include, for example, at step 602, forming a first chamber (e.g., the first chamber 104) having a first width (e.g., width L1) selected according to a vehicle exterior configuration. For example, the width of the first chamber may be selected such that, when inflated, the first chamber has a size and volume sufficient to accommodate a load applied by a first leg and / or knee (e.g., the left leg and / or knee) of a vehicle occupant (e.g., the front seat occupant 14) and also provide protection for the leg / knee to prevent or minimize impact with surrounding vehicle panels. The term "vehicle exterior configuration," as used herein, includes the configuration or geometry of a portion of a vehicle instrument panel (e.g., the instrument panel 20) that faces toward an outboard side (e.g.,the outboard side 26) of the vehicle (e.g., the vehicle 10) and / or any other vehicle panels located on or toward the outboard side (e.g., a glove compartment of a vehicle when the knee airbag is located on the passenger side of the vehicle). For example, the vehicle outboard configuration may include a sweep of a lower portion of the outboard side of the instrument panel.

[0039] The method 600 may further include, at step 604, forming a second chamber (e.g., the second chamber 106) having a second width (e.g., width L2) selected according to a vehicle interior configuration. For example, the width of the second chamber may be selected such that, when inflated, the second chamber has a size and volume sufficient to accommodate a load applied by a second leg and / or knee (e.g., the right leg and / or knee) of the vehicle occupant and also provide sufficient protection for the leg / knee to prevent or minimize impact with surrounding vehicle panels. The term "vehicle interior configuration," as used herein, includes the configuration or geometry of a portion of the vehicle instrument panel that faces toward an inboard side (e.g.,the inboard side 28) of the vehicle and / or any vehicle panels located on or toward the inboard side (e.g., the center console). For example, the vehicle interior configuration may include a sweep of a lower portion of the inboard side of the instrument panel.

[0040] In embodiments, the first and second widths may be selected such that a first volume of the first chamber is greater than a second volume of the second chamber. For example, this may be achieved by selecting the first width to be greater than the second width. In some cases, the first chamber may need to have a larger width because the outboard side of the airbag has a larger surface area coverage than the inboard side of the airbag. In some cases, the first chamber may be configured to have a larger volume because, during a typical loading event, the outboard side of the airbag is expected to absorb more input energy than the inboard side.

[0041] In some embodiments, step 602 includes providing at least one inner wall (e.g., the first baffle 124 and / or the second baffle 126) in the first chamber, a first distance from a first side of the airbag (e.g., an outer side wall of the first chamber), wherein the first distance is equal to the first width. In some embodiments, step 604 includes providing at least one inner wall (e.g., the first baffle 124 and / or the third baffle 128) in the second chamber, a second distance from a second side of the airbag (e.g., an outer side wall of the second chamber), wherein the second distance is equal to the second width and the second side is opposite the first side.The inner walls of the first and second chambers may be configured to prevent gas flow through the walls of the chambers, thereby ensuring proper, independent inflation of each chamber.

[0042] The method 600 may further comprise, at step 606, forming a first vent opening (e.g., the first internal vent opening 116) to allow a first gas flow into the first chamber. Furthermore, at step 608, the method 600 may comprise forming a second vent opening (e.g., the second internal vent opening 118) to allow a second gas flow into the second chamber. In embodiments, the first vent opening may be formed in the at least one internal wall of the first chamber and the second vent opening may be formed in the at least one internal wall of the second chamber. In some embodiments, the method 600 comprises, at step 610, determining a first height (e.g., height d1) for the first vent opening and a second height (e.g.,the height d2) for the second vent opening, such that the first gas flow into the first chamber is greater than the second gas flow into the second chamber. In embodiments, the first height may be selected to be greater than the second height, for example, because the outboard side of the airbag may need to be stiffer than the inboard side to cope with larger expected loads.

[0043] In some embodiments, the method 600 includes, at step 612, coupling at least one inner strap (e.g., straps 130 and / or 132) to the second chamber to reduce a depth of the second chamber relative to the first chamber. In embodiments, the at least one inner strap may be coupled to front and rear sides of the second chamber and have a width less than or equal to the second width of the second chamber. It may be desirable to provide the first chamber with more complete or deeper area coverage than the second chamber due to the different configuration and stiffness of the exterior vehicle components relative to the interior vehicle components.

[0044] In some embodiments, the method 600 includes, at step 614, providing an interior passage (e.g., the interior passage 114) to allow gas flow from an inlet (e.g., the gas inlet) positioned on an exterior wall of the airbag to the first vent opening and the second vent opening. The interior passage may be formed between the first and second chambers and in communication with the first and second vent openings. The width of the interior passage may be dependent on or determined by the first and second widths of the first and second chambers and / or the widths of the interior wall(s) defining each chamber.

[0045] It should be noted that the embodiments described above, especially any "preferred" embodiments, are possible examples of implementations and are set forth merely to enable a clear understanding of the principles of the invention. Many variations and modifications of the above-mentioned embodiment(s) may be made without substantially departing from the spirit and principles of the techniques described herein. All such modifications are within the scope of the present disclosure and are protected by the following claims. This includes any alternative implementation of the embodiments shown in the figures, as in Fig.7, in which functions may be performed in a different order than shown or discussed, including substantially simultaneously or in reverse order, depending on the nature of the function involved, as will be understood by those skilled in the art.

Claims

[1] Vehicle airbag assembly (100) comprising: an airbag (102) comprising a first chamber (104) and a second chamber (106), the first chamber (104) having a larger volume than the second chamber (106) in an inflated state of the airbag (102); a first internal vent opening (116) allowing gas to enter the first chamber (104); and a second internal vent opening (118) allowing gas entry into the second chamber (106), the first internal vent opening (116) being configured for a greater gas flow than the second internal vent opening (118); and one or more inner straps (130,132) coupled to the second chamber (106) to limit the depth of the second chamber (106) in the inflated state, further comprising: a gas inlet (110) arranged on an outer wall of the airbag (102) for inflating the airbag (102); and an internal passage (114) connecting the gas inlet (110) to the first internal vent opening (116) and the second internal vent opening (118), further comprising a plurality of deflection elements (124, 126, 128) defining at least one inner wall of the first chamber (104) and at least one inner wall of the second chamber (106), wherein the first internal vent opening (116) is formed by a first gap between a first deflection element (124) and a second deflection element (126) of the plurality of deflection elements (124, 126, 128), and the second Internal vent opening (118) is formed by a second gap between the first deflection element (124) and a third deflection element (128) of the plurality of deflection elements (124, 126, 128), characterized by , that the height of the third deflection element (128) is greater than the height of the second deflection element (126). [2] The vehicle airbag assembly (100) of claim 1, wherein the width (L1) of the first chamber (104) is greater than the width (L2) of the second chamber (106). [3] The vehicle airbag assembly (100) of claim 1, wherein the second deflection element (126) forms a lower inner wall of the first chamber (104) and the third deflection element (128) forms a lower inner wall of the second chamber (106). [4] The vehicle airbag assembly (100) of claim 1, wherein the first deflection element (124) is disposed opposite the gas inlet (110) and wherein the internal passage (114) is formed between the second deflection element (126) and the third deflection element (128).

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