Roof-mounted occupant restraint system
By installing a multi-chamber roof airbag system in autonomous vehicles, and utilizing different fluid pressure controls and tether structures, the problem of effective deployment of airbag protection systems and occupant protection in unmanned vehicles has been solved, achieving multi-layered buffering and protection effects.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- ZF PASSIVE SAFETY SYST US INC
- Filing Date
- 2018-12-03
- Publication Date
- 2026-06-05
AI Technical Summary
In autonomous vehicles, the lack of traditional vehicle structures such as dashboards and steering wheels makes it difficult for airbag protection systems to be effectively positioned and deployed, thus failing to effectively protect occupants.
The system employs a multi-chamber airbag system mounted on the roof, which utilizes airbag components and tethering structures controlled by different fluid pressures to provide multi-layered protection. The roof is used as a reaction surface to ensure that the airbags effectively deploy and protect occupants during a collision.
It achieves effective occupant protection in autonomous vehicles, ensuring that airbags deploy quickly in a limited space, providing multi-layered buffering and protection, and avoiding reliance on traditional structures.
Smart Images
Figure CN111801250B_ABST
Abstract
Description
[0001] Related applications
[0002] This application claims the benefit of U.S. Provisional Application No. 62 / 666,771, filed May 4, 2018; U.S. Provisional Application No. 62 / 661,667, filed April 24, 2018; and U.S. Provisional Application No. 62 / 636,899, filed March 1, 2018, the entire contents of which are incorporated herein by reference. Technical Field
[0003] The present invention relates generally to vehicle airbags, and more specifically to an airbag mounted on the roof of a vehicle having multiple chambers. Background Technology
[0004] Inflatable vehicle occupant protection devices (such as airbags) are known to help protect vehicle occupants. One particular type of airbag is a frontal airbag that inflates between the front seat occupant and the vehicle's dashboard. Such airbags can be driver airbags or passenger airbags. When inflated, driver and passenger airbags help protect occupants from impacts with vehicle components (e.g., the vehicle's dashboard and / or steering wheel).
[0005] Typically, passenger airbags are stored in a deflated state in a module mounted on the vehicle's dashboard. An airbag door may be connected to the module and / or dashboard to help surround and conceal the airbag in its stored state. When the passenger airbag deploys, the airbag door opens to allow the airbag to move into its inflated state. The opening of the airbag door is a result of the force exerted on the door by the airbag's inflation.
[0006] Typically, the driver's airbag is stored in a deflated state in a module mounted on the vehicle's steering wheel. An airbag cover may be attached to the module and / or the steering wheel to help surround and conceal the airbag in its stored state. When the driver's airbag deploys, the airbag cover opens to allow the airbag to move into its inflated state. The opening of the airbag cover is a result of the force exerted on the cover as the driver's airbag inflates.
[0007] There's a trend in the automotive industry towards making vehicles more spacious. Styling has already resulted in smaller dashboards, and therefore further away from the occupants. Looking ahead, driverless, autonomous vehicles will be even more spacious. Autonomous vehicles have been considered for some time, and their mass adoption is now approaching. Autonomous vehicles can eliminate certain structural features.
[0008] In this context, the paradigm for occupant safety systems must shift. In the past, the necessity of a vehicle operator / driver led to a certain standard vehicle cabin configuration. In the United States, the driver was the forward-facing occupant in the left front seat with access to vehicle controls and instruments (steering wheel, pedals, dashboard, console, etc.). This driver configuration helped determine the layout of the rest of the vehicle (forward-facing passenger-side occupants in the front seats, forward-facing occupants in the rear seats (second row, third row, etc.)). Therefore, in the past, typically, this cabin layout, along with the associated occupant positions and orientations, were considered when designing occupant safety systems.
[0009] Autonomous vehicles eliminate the need for an operator / driver, thus eliminating the need for conventional positioning and orientation of the operator / driver. Vehicle manufacturers are free to utilize the passenger space as they see fit, without being constrained by predetermined passenger arrangements (e.g., all occupants facing forward) or vehicle structural configurations (e.g., steering wheel / dashboard configuration, center console configuration, footwell pedal controls, etc.).
[0010] This presents not only the challenge of where to place the airbag system, but also the challenge of finding a reactive surface against which the airbag rests so that it can absorb the impact. Typically, front airbags mounted on the dashboard and steering wheel utilize these structures as reactive surfaces so that the airbag can resist, mitigate, and absorb the impact energy of an occupant in an impact and provide the desired ride-down effect. However, in autonomous vehicles, the vehicle may not have a dashboard or steering wheel at all, and occupants may be positioned and oriented in unconventional ways. This may make it difficult or impossible to utilize traditional vehicle structures as reactive surfaces. Summary of the Invention
[0011] In one example, a restraint system for helping to protect occupants of a vehicle having a roof and a passenger compartment with seats for the occupants includes a first inflation device and a second inflation device. The first inflation device is used to provide inflation fluid at a first fluid pressure, and the second inflation device is used to provide inflation fluid at a second fluid pressure higher than the first fluid pressure. The airbag includes a stored state within the roof and is inflatable to a deployed state extending into the passenger compartment and aligned with the seats. The airbag includes a first portion and a second portion, the first portion defining a first chamber fluidly connected to the first inflation device, and the second portion defining a second chamber fluidly connected to the second inflation device and fluidly isolated from the first chamber. The first portion moves relative to the second portion in response to an occupant sinking into the first portion.
[0012] In another example, a restraint system for helping to protect occupants of a vehicle having a roof and a passenger compartment with seats for the occupants includes a first inflation device for providing inflation fluid at a first fluid pressure. A second inflation device provides inflation fluid at a second fluid pressure greater than the first fluid pressure. An airbag has a stored state within the roof and is inflatable to a deployed state extending into the passenger compartment and aligned with the seats. The airbag includes panels interconnected by seams to form a first portion and a second portion, the first portion defining a first chamber and the second portion defining a second chamber fluidly isolated from the first chamber. The second portion extends around the entire periphery of the first portion. The first and second chambers are fluidly connected to corresponding first and second inflation devices. The first portion moves relative to the second portion in response to an occupant sinking into the first portion.
[0013] Other objects and advantages of the invention, as well as a more complete understanding of the invention, will become apparent from the following detailed description and accompanying drawings. Attached Figure Description
[0014] Figure 1 It is a top view of a vehicle including an exemplary occupant restraint system mounted on the roof.
[0015] Figure 2 This is a schematic diagram of a vehicle passenger compartment with an airbag in a stored state, equipped with an occupant restraint system.
[0016] Figure 3 It is a schematic representation of the passenger compartment of a vehicle with airbags in the deployed state.
[0017] Figure 4A yes Figure 3 Front view of the airbag.
[0018] Figure 4B It is along Figure 4A The cross-sectional view taken from line 4B-4B.
[0019] Figure 5 yes Figure 3 A schematic illustration of the occupant restraint system after the occupant is trapped in the airbag.
[0020] Figure 6 This is a schematic representation of the passenger compartment of a vehicle with another exemplary occupant restraint system, featuring airbags in the deployed state.
[0021] Figure 7 yes Figure 5 A schematic illustration of the occupant restraint system after the occupant is trapped in the airbag. Detailed Implementation
[0022] The present invention relates generally to vehicle airbags, and more specifically to an airbag mounted on the roof of a vehicle having multiple chambers. Figure 1 and Figure 2 An exemplary vehicle safety system in the form of an occupant restraint system 10 is shown. A vehicle 20 extends along a centerline 22 from a first end or front end 24 to a second end or rear end 26. The vehicle 20 extends to a left side portion 28 and a right side portion 30 on opposite sides of the centerline 22. The first end 24 of the vehicle 20 includes a dashboard 42 facing the passenger compartment or passenger cabin 40. A windshield or deflector 44 may be located between the dashboard 42 and the roof 32.
[0023] Vehicle 20 can be an autonomous vehicle, in which case passenger compartment 40 may be without operator controls (e.g., steering wheel, pedals, instrument panel, center console, etc.). Therefore, dashboard 42 can be reduced in size or completely removed to maximize space in passenger compartment 40.
[0024] Seat 50 is positioned within passenger compartment 40. In this open passenger compartment 40 configuration, vehicle seats 50 can be configured, positioned, and arranged in various ways, without being constrained by the needs of the vehicle driver / operator. For example, in Figure 2 In this configuration, seats 50 can be arranged in the front and rear rows 52 and 54, facing each other, with the front rows facing rearwards towards the rear rows. Alternatively, the front and rear rows 52 and 54 can both be arranged facing forward (not shown), similar to the arrangement in a conventional car. In either case, each seat 50 is equipped with a seatbelt 56 to restrain its occupant 60. For example, control interfaces for climate control, GPS, navigation, entertainment, etc., can be provided in the center console area of the vehicle 20 located between the occupants 60 in the front row 52 and / or the rear row 54.
[0025] for Figure 2 In this unconventional front-to-rear seating arrangement, in the event of a frontal collision, the forward-facing occupants 60 of the rear row 54 are restrained by their respective seatbelts 56. The rear-facing occupants 60 of the front row 52 are restrained by the backrests of the vehicle seats 50 while being buckled in a frontal collision. Therefore, the seats 50 must be configured to support the occupants 60 in the event of a collision. For the forward-facing occupants 60 of the rear row 54, the seatbelts 56 provide a degree of restraint. However, it is desirable that both rows 52 and 54 include additional restraints for head and neck support.
[0026] Since the front row 52 does not need to face forward and is not necessarily adjacent to the dashboard 42 or the area where the dashboard is typically located, there can be a significant amount of space between the front row 52 and the front passenger compartment structure facing forward. Therefore, deploying the airbag from this location may not be effective due to the large volume required. This will cause problems in determining the size of the airbag(s) and inflator(s) to occupy that large volume, and may also cause problems in deploying the airbag(s) to that large volume within the necessary short time required to protect occupants in a collision.
[0027] Therefore, it is evident that the various passenger seating configurations realized by autonomous vehicles may pose challenges to the traditional concept of airbag protection. Furthermore, the lack of typical vehicle architectures (e.g., dashboards) to serve as reaction surfaces presents an additional challenge, as airbags require structures (e.g., reaction surfaces) to support the deployed airbag in response to occupant entrapment.
[0028] With this in mind, Figures 1 to 2 The occupant restraint system 10 shown includes at least one airbag module 68 positioned along the roof 32 of the vehicle 20. Each airbag module 68 includes at least one vehicle occupant protection device in the form of an inflatable curtain airbag 70 and inflator devices 74, 76 for supplying inflation gas to the airbag. Mounting the airbag module 68 in the vehicle roof 32 is convenient because the airbag 70 can be positioned at a desired distance from the occupant 60 it is intended to help protect. This helps reduce the necessary inflatable volume of the airbag 70 and also helps provide the desired airbag deployment time without requiring an excessively large inflator device.
[0029] Airbag module 68 is housed / concealed within the roof structure of vehicle 20, for example, behind headliner 72. Airbag 70 undergoes at least one of rolling up and folding within airbag module 68 before being placed behind headliner 72. Inflators 74, 76 are operably connected (e.g., via wiring) to airbag controller 80 (see... Figure 2 The airbag controller includes or communicates with one or more collision sensors (not shown). The controller 80 is operable to determine the occurrence of a collision event and actuate the inflator devices 74, 76 in a known manner to inflate the airbag 70. The inflator devices 74, 76 can be of any known type, such as gas-storage, solid propellant, pressurized, or hybrid. In any case, the inflator device 74 supplies the airbag 70 with inflation fluid at a first fluid pressure. The inflator device 76 supplies the airbag 70 with inflation fluid at a second fluid pressure greater than the first fluid pressure.
[0030] The airbag 70 can be constructed from any suitable material, such as nylon (e.g., textile nylon 6-6 yarn), and can be constructed in any suitable manner. For example, the airbag 70 may include one or more material pieces or inserts. If more than one material piece or insert is used, these material pieces or inserts can be interconnected in known ways (e.g., stitching, ultrasonic welding, thermal bonding, or adhesive) to form the airbag 70. The airbag 70 can be uncoated, coated with a material (e.g., impermeable urethane), or laminated with a material (e.g., an impermeable membrane). Thus, the airbag 70 can have an airtight or substantially airtight construction. Those skilled in the art will recognize that alternative materials (e.g., polyester yarn) and alternative coatings (e.g., silicone) can also be used to construct the airbag 70.
[0031] The occupant restraint system 10 may include a plurality of airbag modules 68 disposed along the roof 32 and within the headliner 72 at a position associated with and aligned with the seats 50 in each row 52, 54. In other words, each seat 50 in the vehicle 20 may have a separate airbag module 68, and therefore each seat may have a separate airbag 70 associated with and aligned therewith. In each case, the airbag 70 is positioned in front of the associated seat 50 in each row 52, 54 in the direction that the occupants 60 in these seats will be facing (i.e., behind the front row 52 and in front of the rear row 54).
[0032] Airbag 70 extends in the left-right direction of vehicle 20 and is generally parallel to the width of seat 50. Alternatively, a single airbag 70 may span the entire width of passenger compartment 40 to protect all passengers 60 (not shown) in a row 52 or 54. Figure 2 In the example shown, airbag 70 is positioned behind headliner 72 and associated with seat 50 in each row 52, 54. Airbag module 68 is identical, and therefore, for the sake of brevity, the construction and operation of the airbag module associated only with the seat 50 in the rear row 54 will be discussed.
[0033] like Figure 3 As shown, upon sensing an event that would cause the airbag 70 to inflate (e.g., a vehicle collision), the controller 80 provides a signal to the inflators 74 and 76. Upon receiving the signal from the controller 80, the inflators 74 and 76 are actuated and supply inflation fluid to the inflatable volume of the airbag 70 in a known manner. The inflating airbag 70 applies force to the headliner 72, causing the headliner to deploy. This releases the airbag 70 to inflate and deploy from its stored state behind the headliner 72 to a deployed state extending into the passenger compartment 40, in front of and aligned with the seat 50 in the rear seat 54. The airbag 70 helps protect the vehicle occupants 60 in the rear seat 54 by absorbing the impact of the occupants' impact while inflating.
[0034] The inflatable airbag 70 extends from its upper end 82 to its lower end 84 after deployment. The upper end 82 is connected to the vehicle 20 and fluidly connected to the inflators 74 and 76. The lower end 84 is positioned near the occupant 60 in the rear seat 50 of the rear row 54. (See reference...) Figures 4A to 4B The airbag 70 includes an inflatable volume 90 defined by opposing material panels 92, 94 and between these panels. The panels 92, 94 may be separate material pieces fastened together or integrally formed from each other in a one-piece woven manner. The panels 92 face the occupants 60 in the rear row 54 in the rearward direction of the vehicle 20. The panels 94 face away from the occupants 60 in the rear row 54 in the forward direction of the vehicle 20.
[0035] A seam 96 extends through the two panels 92, 94 to divide the airbag 70 into a first portion and a second portion 98, 102, which define corresponding first and second chambers 100, 104 of the inflatable volume 90. The seam 96 can have any configuration suitable for fluidly isolating the first and second chambers 100, 104 from each other. In one example, the seam 96 has a rectangular shape to define a polygonal (e.g., square or rectangular) first portion 98. Alternatively, the seam 96 can be round, circular, elliptical, etc. (not shown).
[0036] The second portion 102 extends around the periphery of the first portion 98. Although the second portion 102 extends around the entire periphery of the first portion 98, the second portion may alternatively extend around a portion of the first portion (not shown). The second portion 102 may have a circular or rectangular cross-section extending along a centerline 106 parallel to the joint 96.
[0037] The first chamber 100 is fluidly connected to the first inflation device 74 and thus receives inflation fluid at a first fluid pressure. The second chamber 104 is fluidly connected to the second inflation device 76 and thus receives inflation fluid at a greater second fluid pressure. Since chambers 100 and 104 are fluidly isolated from each other, the second portion 102 is more rigid and less prone to deformation than the first portion 98.
[0038] As noted, there is no vehicle structure in a suitable position to serve as a reaction surface to restrain the movement of the deployed airbag 70. Therefore, the occupant restraint system 10 may include one or more tethers 110 ( Figure 3The one or more tethers are associated with each airbag 70 and extend from each airbag to a location near or on the roof 32. Each tether 110 is formed of a single piece of non-stretchable material and extends from a first end 112 connected to the lower end 84 of the airbag 70 to a second end 114 connected to the roof 32. The first end 112 may be configured as a stress reducer to distribute the connection between the tether 110 and the airbag 70 over a larger surface area of the airbag fabric to prevent tearing.
[0039] like Figure 1 As shown, two tethers 110 are attached to the roof 32 on opposite sides of the airbag 70, i.e., inside and outside each airbag. The tethers 110 associated with the airbag 70 near each rear seat 54 are attached to the roof 32 at a location behind the occupant-facing panel 92 of the airbag. Because the occupant 60 is strapped in, a frontal collision causing the occupant to move forward results in the occupant bending at the waist and following an angled or arc-shaped path toward the airbag 70, as... Figure 3 As indicated by arrow F in the diagram. Advantageously, as... Figure 3 As shown, the position of the second end 114 / roof 32 connection can be selected such that the tether 110 extends in a direction or along a path that approximates or coincides with (i.e., is substantially parallel to or extends along with) the path along which the occupant 60 travels and comes into contact with the airbag 70.
[0040] In this way, the tension applied to the airbag 70 by the tether 110 can be opposite to the impact force applied to the airbag by the trapped occupant 60. As a result, the roof 32 serves as a reaction surface for the airbag 70 via the tether 110. Figure 3 The exemplary configuration therefore does not require interaction with the front structure of the vehicle 20 (such as the dashboard, steering wheel, or seats) to provide a reactive surface for the airbag.
[0041] After the airbag 70 deploys but before the occupant 60 sinks in, the deployed airbag fully tensions the tether 110. The tether 110 holds the lower end 84 of the airbag 70 in the position shown to prevent the airbag from swinging / pivoting around the inflation devices 74, 76 when the occupant 60 sinks in. The occupant 60 moves in path F and eventually impacts and sinks into the inflated and deployed airbag 70.
[0042] The higher inflation fluid pressure of the second section 102 (which is connected to the tether 110 and the vehicle 20 via its connecting portion) helps ensure that the second section maintains its stiffness during the occupant 60's entrapment. Therefore, the deformation of the second section 102 is relatively negligible or nominal when the occupant 60 is entrapped in the airbag 70. On the other hand, the lower inflation fluid pressure of the first section 98 (relative to the second section 102) causes the panel 92 to move forward approximately in direction F within the vehicle 20 along with the entrapped occupant 60. In other words, the stiffness difference between the first section 98 and the second section 102 allows the first section to move with the entrapped occupant 60, while the second section is substantially held in place by the vehicle 20 and the tether 110.
[0043] This configuration allows the occupant 60 to be cushioned on the airbag 70 and experience a smoother reaction to the airbag, while the tether 110 and roof 32 provide reaction surfaces for the deploying, moving airbag. In other words, providing multiple chambers 100, 104 for the airbag 70, filled with different fluid pressures, advantageously allows the occupant 60, trapped in the airbag 70, to decelerate more smoothly in a predetermined manner. For this purpose, the inflation devices 74, 76 can be configured to provide a first inflation fluid pressure and a second inflation fluid pressure, which allow the panel 92 to move in response to the occupant 60 being trapped in the airbag 70 and cushion a predetermined amount.
[0044] exist Figures 6 to 7 In another exemplary occupant restraint system 10a shown, the tether 110 is omitted. (See reference...) Figure 6 The airbag 70a is configured to deploy downwards to engage with the occupant 60 (e.g., engage the occupant's thighs and / or lower torso). The degree of engagement of the occupant 60 and the pressure of the second inflation fluid supplied by the second inflation device 76 are selected to help ensure that the lower end 84 of the airbag 70a is held in place when the occupant 60 is engaged in the first portion 98.
[0045] In other words, the lower end 84 is held in place by engaging the thigh of the occupant 60 to prevent the airbag 70a from sinking into the first part 98 in response to movement of the occupant in direction F (see...). Figure 7 And swing / pivot. Therefore, the lower end 84 of the airbag 70a in the occupant restraint system 10 functions similarly to the tether 110 in the occupant restraint system 10a. In this way, the occupant's 60 thighs serve as a reaction surface for the airbag 70a. Figure 6 The exemplary configuration therefore does not require interaction with the front structure of the vehicle 20 (such as the dashboard, steering wheel, or seats) to provide a reactive surface for the airbag.
[0046] Occupant 60 then interacts with the deployed airbag 70a in the same manner as described above. Specifically, occupant 60 moves along path F and eventually impacts and sinks into the inflated and deployed airbag 70a. The stiffness difference between the first part 98 and the second part 102 allows the first part to move with the sinking occupant 60, while the second part is substantially held in place by the vehicle 20 and the occupant 60's thighs. This configuration allows occupant 60 to be cushioned on the airbag 70a and experience a smoother reaction to the airbag, while the occupant's thighs provide a reaction surface for the moving airbag as it deploys.
[0047] Although the description of airbag 70 and tether 110 (if present) above refers to the rear seat 50 of the 54th row, it will be understood that the same airbags and tethers can be provided for the front seats of the 52th row (see [link to relevant documentation]). Figures 1 to 2 Because the seats 50 in rows 52 and 54 face opposite directions, the corresponding airbags 70 serve different purposes. In a frontal collision, the rear-facing seats 50 in the front row 52 will help protect the occupants by absorbing the impact of the occupants 60. The airbags 70 in the forward-facing rear seats 50 in the rear row 54 will help protect the occupants by absorbing the impact energy of the occupants 60. In a rear-end collision, the backrests of the forward-facing seats 50 in the rear row 54 will help protect the occupants 60 by absorbing the impact of the occupants. The airbags 70 in the rear-facing seats 50 in the front row 52 will help protect the occupants by absorbing the impact energy of the occupants 60.
[0048] The examples described above are examples of the invention. It is certainly impossible to describe every conceivable combination of components or methods for the purposes of describing the invention, but those skilled in the art will recognize that many other combinations and substitutions of the invention are possible. Therefore, the invention is intended to cover all such changes, modifications, and variations that fall within the spirit and scope of the appended claims.
Claims
1. A restraint system for helping to protect occupants of a vehicle, the vehicle having a roof and a passenger compartment having seats for the occupants, the restraint system comprising: A first inflation device, the first inflation device being used to provide inflation fluid at a first fluid pressure; A second inflation device is used to provide inflation fluid at a second fluid pressure greater than the first fluid pressure; An airbag having a stored state within the roof and an inflatable deployed state extending into the passenger compartment and aligned with the seats; the airbag includes a first portion and a second portion, the first portion defining a first chamber fluidly connected to a first inflator, the second portion defining a second chamber fluidly connected to a second inflator and fluidly isolated from the first chamber, the first portion moving relative to the second portion in response to an occupant sinking into the first portion.
2. The constraint system according to claim 1, wherein, The first part of the airbag is rectangular, and the second part extends around the periphery of the first part.
3. The constraint system according to claim 1, wherein, The second part extends around the entire periphery of the first part.
4. The constraint system according to claim 1, wherein, The second portion has a circular cross-section around a centerline that extends parallel to the periphery of the first portion.
5. The restraint system of claim 1, further comprising at least one tether having a first end and a second end, the first end being secured to the second portion and the second end being connected to the roof for limiting the movement of the second portion of the airbag in response to an occupant sinking into the first portion.
6. The constraint system according to claim 5, wherein, The airbag extends from a first end connected to the vehicle to a second end positioned near the seat, and the first end of the tether is connected to the second end of the airbag.
7. The constraint system according to claim 1, wherein, The second portion is configured to deploy and engage with the occupant to limit the movement of the second portion of the airbag in response to the occupant sinking into the first portion.
8. The constraint system according to claim 1, wherein, The first part moves relative to the second part in the forward direction of the vehicle in response to an occupant getting into the first part.
9. The constraint system according to claim 1, wherein, The first part moves relative to the second part in the rearward direction of the vehicle in response to an occupant getting into the first part.
10. The constraint system according to claim 1, wherein, The airbag includes a first panel and a second panel, which are interconnected by a seam to define the first portion and the second portion.
11. The constraint system according to claim 1, wherein, Only inflation fluid from the first inflation device enters the first chamber, and only inflation fluid from the second inflation device enters the second chamber.
12. A restraint system for helping to protect occupants of a vehicle, the vehicle having a roof and a passenger compartment having seats for the occupants, the restraint system comprising: A first inflation device, the first inflation device being used to provide inflation fluid at a first fluid pressure; A second inflation device is used to provide inflation fluid at a second fluid pressure greater than the first fluid pressure; An airbag having a stored state within the roof and an inflatable deployed state extending into the passenger compartment and aligned with the seats; the airbag includes panels interconnected by seams to form a first portion defining a first chamber and a second portion defining a second chamber fluidly isolated from the first chamber, the second portion extending around the entire periphery of the first portion, the first chamber and the second chamber being fluidly connected to corresponding first and second inflation devices, the first portion moving relative to the second portion in response to an occupant sinking into the first portion.
13. The constraint system according to claim 12, wherein, The first part of the airbag is rectangular.
14. The constraint system according to claim 12, wherein, The second portion has a circular cross-section around a centerline that extends parallel to the periphery of the first portion.
15. The restraint system of claim 12, further comprising tethers, each tether having a first end and a second end, the first end being secured to the second portion and the second end being connected to the roof for restricting movement of the second portion of the airbag in response to an occupant sinking into the first portion.
16. The restraint system according to claim 15, wherein, The airbag extends from a first end connected to the vehicle to a second end positioned near the seat, with the first end of each tether connected to the second end of the airbag.
17. The constraint system according to claim 12, wherein, The second portion is configured to deploy and engage with the occupant to limit the movement of the second portion of the airbag in response to the occupant sinking into the first portion.
18. The restraint system according to claim 12, wherein, The first part moves relative to the second part in the forward direction of the vehicle in response to an occupant getting into the first part.
19. The restraint system according to claim 12, wherein, The first part moves relative to the second part in the rearward direction of the vehicle in response to an occupant getting into the first part.
20. The restraint system according to claim 12, wherein, Only inflation fluid from the first inflation device enters the first chamber, and only inflation fluid from the second inflation device enters the second chamber.