Inflatable device for driver airbag

An assembly for a vehicle includes a steering wheel having a hub, an airbag supported by the hub and inflatable to an inflated position, and an inflatable device supported by the hub and inflatable to an inflatable position. The inflatable device defines an inflation chamber. The inflatable device is a thermoplastic elastomer (TPE).

BACKGROUND

Vehicles are equipped with airbags. In the event of an impact, an inflator activates and provides inflation medium to the airbags, and the airbags pressurize and act as supplemental restraints for occupants during the impact. The airbags are located at various fixed positions in passenger cabins of vehicles. Vehicles typically include a driver airbag mounted in the steering wheel. Upon inflation, a rim of the steering wheel may act as a reaction surface for the driver airbag.

DETAILED DESCRIPTION

An assembly includes a steering wheel having a hub, an airbag supported by the hub and inflatable to an inflated position, and an inflatable device supported by the hub and inflatable to an inflated position. The inflatable device defines an inflation chamber and is a thermoplastic elastomer.

The steering wheel includes a rim, the rim being between the airbag and the inflatable device when the airbag and the inflatable device are in an inflated position.

The rim may be non-circular.

The assembly may include an instrument panel, the inflatable device being between the steering wheel and the instrument panel.

The inflatable device may include an outward panel, an inward panel between the outward panel and the hub, and a side panel extending from the inward panel to the outward panel, the side panel being folded when the inflatable device is in an uninflated position. The side panel may be an endless loop between the outward panel and the inward panel. The outward panel may be thicker than the side panel. The inward panel may be thicker than the side panel. The outward panel may be flush with the hub in the uninflated position. The assembly may include a tear seam between the outward panel and the hub. The hub may define a recess and the inflatable device may be disposed in the recess. The outward panel may be arcuate about the hub in the inflated position. The steering wheel includes a rim and the side panel may be planar and abut the rim in the inflated position.

The assembly may include a second inflatable device supported by the hub and inflatable to an inflated position, the second inflatable device defining a second inflation chamber and being a thermoplastic elastomer. The inflatable device may be fluidly isolated from the second inflatable device. The airbag may abut the inflatable device and the second inflatable device when in the inflated position. The hub may define a recess extending endlessly around the hub and the inflatable device and the second inflatable device may be disposed in the recess.

The airbag may be woven fabric.

The inflatable device may be configured to extend into a knee area of a passenger cabin.

With reference to the Figures, wherein like numerals indicate like parts throughout the several views, an assembly10for a vehicle12is generally shown. The assembly10includes a steering wheel14having a hub16, an airbag18supported by the hub16and inflatable to an inflated position, and an inflatable device22supported by the hub16and inflatable to an inflatable position. The inflatable device22defines an inflation chamber24. The inflatable device22is a thermoplastic elastomer (TPE).

The inflatable device22acts as a reaction surface for the airbag18in the event of an impact of the vehicle12. The inflatable device22may limit rotation of the airbag18by supporting the airbag18in the event of an impact to the vehicle12. Since the inflatable device22provides a reaction surface for the airbag18, the airbag18may be used with a non-circular steering wheel14, as discussed below.

The vehicle12may be any suitable type of automobile, e.g., a passenger or commercial automobile such as a sedan, a coupe, a truck, a sport utility vehicle, a crossover vehicle, a van, a minivan, a taxi, a bus, etc. The vehicle12, for example, may be an autonomous vehicle. In other words, the vehicle12may be autonomously operated such that the vehicle12may be driven without constant attention from a driver, i.e., the vehicle12may be self-driving without human input.

The vehicle12defines a passenger cabin28to house occupants, if any, of the vehicle12. The passenger cabin28may extend across the vehicle12, i.e., from one side to the other side of the vehicle12. The passenger cabin28includes a front end and a rear end with the front end being in front of the rear end during forward movement of the vehicle12.

The vehicle12may include an instrument panel20. The instrument panel20may be disposed at front end of the passenger cabin28. The instrument panel20may support vehicle controls, including the steering wheel14. The instrument panel20may extend across the front end of the passenger cabin28from one side of the vehicle12to the other side of the vehicle12.

The vehicle12includes a steering system (not numbered). The steering system controls the turning of the wheels. The steering system is in communication with and receives input from the steering wheel14. The steering system may include a rack-and-pinion system with electric power-assisted steering, a steer-by-wire system, as are both known in the art, or any other suitable system. The steering wheel14allows an operator to steer the vehicle12by transmitting rotation of the steering wheel14to movement of a steering rack. The steering system includes a steering column supporting the steering wheel14. The steering system may include a steering column shroud58covering the steering column in the passenger cabin28. The steering column shroud58is between the instrument panel20and the inflatable device22, and the inflatable device22is between the airbag18and the steering column shroud58.

With reference toFIGS. 1-3, the hub16of the steering wheel14is rotatable about a rotational axis A (identified inFIG. 1). The rotational axis A generally extends in a vehicle longitudinal direction. As an operator rotates the steering wheel14to turn the vehicle12, the hub16rotates about the rotational axis A.

The steering wheel14includes a rim26supported by the hub16. The rim26may be spaced from the hub16. Specifically, the steering wheel14may include a space between the rim26and the hub16so that the rim26may be gripped by the driver.

The rim26is supported by the hub16. The rim26is spaced radially from the hub16. The rim26may include multiple segments spaced from the hub16and spaced from each other, e.g., paddles shown in the Figures, that may be gripped by a vehicle driver. In such an example, the steering wheel14may include two paddles spaced from each other in a cross-vehicle direction when the steering wheel14is steered straight. In such an example, the steering wheel14is non-circular, as described further below. The hub16may be centrally disposed relative to the rim26.

The steering wheel14may include one or more arms44extending from the hub16to the rim26. For example, as shown in the Figures, the steering wheel14includes a pair of arms44extending from the hub16to the rim26. The arms44may extend from the hub16to the rim26, e.g., to the paddles. The steering wheel14may include any suitable number of arms44extending from the hub16to the rim26. The arms44may extend radially outwardly relative to the rotational axis A from the hub16to the rim26. When the airbag18and the inflatable device22are in the inflated position, the arms44are between the airbag18and the inflatable device22. The airbag18and the inflatable device22may abut the arms44when the airbag18and the inflatable device22are in the inflated positions.

The steering wheel14may be non-circular, as shown in the Figures. Specifically, the rim26may be non-circular circumferentially about the hub16. As one example, the rim26may be longer in one direction than another. As another example in which the rim26is non-circular, the rim26may include at least two paddles that are discontinuous relative to each other about the hub16and spaced from the hub16in a cross-vehicle direction when the steering wheel14is steered straight. As other examples of the rim26being non-circular, the rim26may be endless and be, e.g., oval, rectangular, rounded rectangular etc. In other examples the rim26may be circular, i.e., a ring.

The steering wheel14, e.g., the rim26, includes a top50, a bottom52spaced from the top50, and two sides54spaced from each other and each extending from the top50to the bottom52. Specifically, the rim26may define the top50, bottom52, and sides54of the steering wheel14. The top50of the steering wheel14is above the bottom52of the steering wheel14when the steering wheel14is steered straight.

In the example shown in the Figures including the paddles, the paddles may be separated by a gap56. The gap56may be positioned at the top50of the steering wheel14and/or at the bottom52of the steering wheel14. The gaps56may be elongated in the cross-vehicle direction. In the example shown in the Figures, the rim26includes one gap56at the top50, one gap56at the bottom52, and two paddles at the sides54, respectively.

The assembly10includes an airbag assembly (not numbered) supported by the hub16of the steering wheel14. With reference toFIG. 5, the airbag assembly includes the airbag18and an inflator62and may include a housing60. The inflator62inflates the airbag18from an uninflated position (FIG. 1) to an inflated position (FIG. 2). In an example in which the airbag assembly includes the housing60, the inflator62of the airbag assembly may be supported by the housing60. In an example including the housing60, the housing60may be of any material, e.g., a rigid polymer, a metal, a composite, etc.

The airbag18is supported by the hub16and is inflatable from an uninflated position to an inflated position. As an example, the airbag assembly may include the housing60connected to the hub16with the airbag18supported by the housing60. In such an example, the housing60of the airbag assembly is supported by the steering wheel14. Specifically, the housing60is supported by the hub16of the steering wheel14and the airbag18is supported by the hub16through the housing60. The airbag18inflates away from the hub16toward the driver in a vehicle-rearward direction.

The airbag18may be referred to as a driver airbag. The airbag18may be supported on the vehicle-rearward side of the steering wheel14, i.e., the airbag18is supported by the hub16on the vehicle-rearward side of the steering wheel14. As a driver turns the steering wheel14about the rotational axis A to turn the vehicle12, the airbag18rotates about the rotational axis A along with the steering wheel14.

The airbag18may be inflatable along the rotational axis A toward the rear end of the passenger cabin28, i.e., the airbag18may extend into the passenger cabin28toward a driver seat when the airbag18is in the inflated position. When the airbag18inflates to the inflated position, the airbag18extends radially from the rotational axis A. The airbag18may extend radially outwardly relative to the rotational axis A farther than the rim26of the steering wheel14extends radially outwardly relative to the rotational axis A when the airbag18is in the inflated position.

The airbag18may be woven nylon yarn, for example, nylon 6. Other examples include polyether ether ketone (PEEK), polyetherketoneketone (PEKK), polyester, etc. The woven polymer may include a coating, such as silicone, neoprene, urethane, etc. For example, the coating may be polyorgano siloxane.

The inflator62of the airbag assembly is in fluid communication with the airbag18. The inflator62expands the airbag18with inflation medium, such as a gas, to move the airbag18from the uninflated position to the inflated position. The inflator62may be supported by any suitable component. For example, the inflator62may be supported by the housing60, as described above. The inflator62may be, for example, a pyrotechnic inflator that ignites a chemical reaction to generate the inflation medium, a stored gas inflator that releases (e.g., by a pyrotechnic valve) stored gas as the inflation medium, or a hybrid. The inflator62may be, for example, at least partially in the inflation chamber of the airbag18to deliver inflation medium directly to the inflation chamber or may be connected to the inflation chamber through fill tubes, diffusers, etc.

With reference toFIGS. 3-6, the inflatable device22is supported by the hub16. The inflatable device22may be disposed in the hub16in the uninflated position and extend from and remain supported by the hub16in the inflated position. The inflatable device22inflates radially away from the hub16.

The assembly10may include more than one inflatable device22. The example shown in the Figures, as an example, includes two inflatable devices22, i.e., a first inflatable device22and a second inflatable device22. In examples including more than one inflatable device22, the inflatable devices22may have common design and function. In the example shown in the Figures, the inflatable devices22are mirror images of each other. In examples including multiple inflatable devices22, the inflatable devices22may be fluidly isolated, i.e., the inflation chambers24of the inflatable devices22are not in fluid communication with each other.

The airbag18may abut the inflatable device22when in the inflated position. When both the airbag18and the inflatable device22are in the inflatable position, the airbag18contacts the side panel38of the inflatable device22. This contact may allow the inflatable device22to act as a reaction surface to control the kinematics of a driver during impact of the driver against the airbag18. For example, during a vehicle impact in which the driver is urged in a vehicle12forward direction, as the driver moves toward the instrument panel20, the airbag18is pushed against the inflatable device22and the inflatable device22offers resistance to the vehicle12forward movement of the driver, thereby controlling the kinematics of the driver. The inflatable device22acts as a reaction surface because the material of the inflatable device22, i.e., the thermoplastic elastomer, is more rigid than the material of the airbag18and/or because the inflatable device22abuts another component vehicle-forward of the inflatable device, e.g., the instrument panel20.

The inflatable device22is between the rim26of the steering wheel14and the instrument panel20in both the uninflated position and the inflated position. Specifically, in the uninflated position, the rim26extends from the hub16vehicle forward of the location of the inflatable device22in the hub16.FIG. 6shows the inflatable device22between the rim26and the instrument panel20.

The rim26is between the airbag18and the inflatable device22when the airbag18and the inflatable device22are in the inflated position. Specifically, the airbag18inflates vehicle-rearward from the steering wheel14and vehicle-rearward of the rim26. The inflatable device22inflates radially from the steering wheel14vehicle-forward of the rim26. The inflatable device22and the airbag18may both abut the rim26in the inflated position, as shown inFIG. 6.

As set forth above, the inflatable device22is a thermoplastic elastomer. Specifically, the inflatable device22has walls that are thermoplastic elastomer (TPE). The walls of the inflatable device22define the inflation chamber24. A thermoplastic elastomer has both thermoplastic and elastomeric properties. Types of TPEs include styrenic block copolymers, thermoplastic olefins, elastomeric alloys, thermoplastic polyurethanes, thermoplastic copolyesters, and thermoplastic polyamides. The material of the walls of the inflatable device22is solid, not woven, fabric, etc. As an example, the inflatable device22, and specifically the walls of the inflatable device22may be formed by injection molding.

The assembly10includes an inflator32. The inflator32is in fluid communication with the inflation chamber24. The inflation chamber24is filled with inflation medium that inflates the inflatable device22. Specifically, the inflator32expands the inflation chamber24with inflation medium, such as a gas, to move the inflatable device22from the uninflated position to the inflated position. In examples including more than one inflatable device22, the assembly10may include one inflator32that feeds each inflatable device22or may include multiple inflators32each dedicated to in inflatable device22. The inflator32may be supported by any suitable component. For example, the inflator32may be supported by the hub16. The inflator32may be, for example, a pyrotechnic inflator that ignites a chemical reaction to generate the inflation medium, a stored gas inflator that releases (e.g., by a pyrotechnic valve) stored gas as the inflation medium, or a hybrid. The inflator32may be, for example, at least partially in the inflation chamber24to deliver inflation medium directly to the inflation chamber24or may be connected to the inflation chamber24through fill tubes, diffusers, etc.

The inflatable device22includes an outward panel34, an inward panel36, and a side panel38. The outward panel34forms the outermost surface of the inflatable device22with respect to the hub16. The inward panel36is between the outward panel34and the hub16. The inflatable device22may be connected to the hub16at the inward panel36. The side panel38extends from the inward panel36to the outward panel34. The side panel38may be an endless loop. The outward panel34, inward panel36, and side panel38may be unitary, i.e., a single, uniform piece of material with no seams, joints, fasteners, or adhesives holding them together. As an example, outward panel34, the inward panel36, and the side panel38may be formed together simultaneously as a single continuous unit, e.g., by injection molding. Non-unitary components, in contrast, are formed separately and subsequently assembled, e.g., by adhesive, welding, etc.

With reference toFIGS. 3 and 7, the side panel38is folded when the inflatable device22is in an uninflated position. The side panel38is folded in an accordion fashion. The folding of the side panel38compresses the inflatable device22and allows the inflatable device22to be packaged with the hub16.

The outward panel34may be thicker than the inward panel36and/or the side panel38. As an example, the outward panel34may have a wall thickness of 4-8 mm thick, the side panel38may have a wall thickness of 2-4 mm, and the side panel38may have a wall thickness of 2-4 mm.

The outward panel34may be arcuate about the hub16in the uninflated position and/or in the inflated position. Specifically, the outward panel34may curve circumferentially about the hub16, e.g., about the rotational axis A. In the uninflated position, the outward panel34may follow contours of the hub16, as described below. In the inflated position, the outward panel34may be semi-circular. In the example including two inflatable devices22, the inflatable devices22may abut each other to, in combination, encircle the hub16about the rotational axis A. Specifically, in the uninflated position, the outward panels34may abut each other to encircle the hub16. In the inflated position, portions of the side panels38may abut each other so that the inflatable devices46, in combination, encircle the hub16.

The outward panel34may be flush with an outer surface64of the hub16in the uninflated position, as shown inFIG. 3. Specifically, as shown inFIG. 7, the hub16may be recessed such that the outer surface64of the hub16is flush with the outward panel34when the inflatable device22is connected to the hub16. In such an example, the hub16may have a recess40that receives the inflatable device22. As set forth above, the side panel38may be folded in the uninflated position to accommodate for packaging in the recess40with the outward panel34flush with the outer surface64of the hub. The recess40may be endless around the hub16. For example, in the example including two inflatable devices22, the inflatable devices22may abut each other to extend endless around the hub16in the recess.

The outward panel34may follow the contours of the outer surface64of the hub16. The outward panel34may have a class-A surface. Specifically, the outward panel34may match the appearance of the outer surface64of the hub16such that the inflatable device22is concealed in the uninflated position.

In one example, as shown inFIG. 7, the inflatable device22is fixed to the hub16. In such an example, the inflatable device may have connections68that engage the hub16in the recess40. For example, the connections68may be Christmas tree fasteners engageable with holes72in the hub. In such an example, the connections68may be unitary with the inward panel36, as shown inFIG. 7. In addition or in the alternative, connections70may extend through the outward panel34and the outer surface64to engage the inflatable device22to the hub16. As an example, the connections70may be threaded fasteners. In the example shown inFIG. 7, the outward panel34may have a tear seam66that allows the inflatable device22to release and expand to the inflated position. The tear seam66may be, for example, a line of decreased material thickness and/or perforations to induce tearing along the tear seam66when subjected to sufficient force.

As another example, the hub16and the inflatable device22may be unitary i.e., a single, uniform piece of material with no seams, joints, fasteners, or adhesives holding them together. As an example, hub16and the inflatable device22may be formed together simultaneously as a single continuous unit, e.g., by injection molding. In examples in which the hub16and the inflatable device22are unitary, the hub16and the inflatable device22may be joined at a tear seam. The tear seam may be, for example, a line of decreased material thickness and/or perforations to induce tearing along the tear seam when subjected to sufficient force.

The vehicle12may include a computer, e.g., a restraints control module. The computer may be a microprocessor-based computing device implemented via circuits, chips, or other electronic components. For example, the computer may include a processor, memory, etc. The memory of the computer may store instructions executable by the processor as well as data and/or databases. The processor is programmed to initiate an inflation of the airbag18and inflation of the inflatable device22in response to a vehicle impact. Specifically, the processor is programmed to activate the inflators32,62in response to a vehicle impact.

The vehicle12may include an impact sensor (not shown). The impact sensor is programmed to detect an impact to the vehicle12. The impact sensor may be of any suitable type, for example, post-contact sensors such as accelerometers, pressure sensors, and contact switches; and pre-impact sensors such as radar, LIDAR, and vision-sensing systems. The vision systems may include one or more cameras, CCD image sensors, CMOS image sensors, etc. The impact sensor may be located at numerous points in or on the vehicle12.

The vehicle12may include a communication network. The communication network includes hardware, such as a communication bus, for facilitating communication among vehicle components. The communication network may facilitate wired or wireless communication among the vehicle components in accordance with a number of communication protocols such as controller area network (CAN), Ethernet, WiFi, Local Interconnect Network (LIN), and/or other wired or wireless mechanisms. The computer, impact sensors, and inflators32,62are in communication on the communication network.

During a vehicle impact detected by the impact sensors, the computer instructs the inflators32,62to activate. The inflator32inflates the inflatable device22and the inflator62inflates the airbag18. As described above, the inflatable device22acts as a reaction surface for the airbag18to position the airbag. Specifically, the inflatable device22retains the airbag18in a vehicle-rearward position of the inflatable device22to position the airbag18relative to an occupant and to control movement of the airbag18when impacted by an occupant so that the airbag18controls the kinematics of the occupant. The inflatable device22may control the kinematics of the occupant. For example, in an example shown in the Figures, one of the inflation devices22extends downwardly from the steering wheel14and controls the kinematics of the knees of the vehicle12occupant when in the inflated position. Specifically, the inflatable device22is configured to extend into a knee area of a passenger cabin28. The knee area of the passenger cabin is the volume typically occupied by the knees of an occupant in the seat of the vehicle12. Specifically, the knee area is between the inflatable device22in the inflated position and a seat bottom of the seat.