Inflatable seat belt including a thorax airbag

A seat belt assembly for use in a seat belt system of a motor vehicle to restrain a vehicle occupant. The assembly includes a belt webbing extending from a first end to a second end and includes tubular webbing extending from the first end and configured to open at a tear seam. An airbag is disposed within the tubular webbing and configured to inflate and deploy through the tear seam. A gas generator is fluidly coupled to the airbag and configured to provide an expanding gas to inflate and deploy the airbag in response to a control signal. A first part of the airbag is configured to inflate above the tubular webbing such that the first part of the airbag is disposed between a side or door of the vehicle and the thorax of the vehicle occupant.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to automotive safety restraint systems. In particular, the invention relates to safety belt systems having webbing integrated airbags.

2. Description of Related Art

Numerous designs of passive and active automotive occupant restraint systems are known for enhancing occupant protection in the event of a vehicle impact. Passive systems are deployed with no action required by the occupant and include inflatable restraints, air bags for frontal and side impacts, and automatically deployed seat belt systems. Active systems, such as seat belts, have been used for many decades and are manually deployed by the occupant. The conventional seat belt system uses three points of connection with the vehicle structure or a vehicle seat and incorporates a lap belt portion for engaging the occupant's lower torso or pelvis, and a shoulder belt portion for engaging the occupant's upper torso or thorax. When engaged by the occupant, the seat belt restrains movement of the occupant in the event of a vehicle impact or rollover event.

One development in the area of seat belts includes inflatable seat belt systems. An inflatable seat belt system incorporates an airbag into a section of the belt webbing which is inflated by a gas, typically by means of a pyrotechnic inflator, to increase its size and volume. When an inflatable seat belt is activated, the airbag expands and the normally narrow seat belt webbing increases in area and volume to significantly reduce the contact pressure between the belt and the occupant during an impact event. The airbag also acts as a belt pretensioner since the inflatable section fills in the slack area between the occupant and the belt webbing.

However, conventional inflatable seat belts pose a number of design challenges. For example, typical inflatable seat belts dispose the inflatable section in the shoulder belt portion. The increased thickness of the inflatable belt section creates difficulties with cycling the webbing through a D-ring of the seat belt system. Additionally, occupants of different sizes draw differing amounts of the shoulder belt portion across their thorax, creating problems with properly positioning the inflatable belt section. Another disadvantage stems from the fact that they are primarily effective in frontal impact events. To protect against side impacts, an additional side impact or thorax airbag is often installed in the seat or another structure of the motor vehicle.

Motor vehicle designers are continually striving to provide enhanced performance of occupant protection systems while reducing the complexity and weight of vehicle systems while enhancing component packaging.

SUMMARY OF THE INVENTION

In satisfying the above need, as well as overcoming the enumerated drawbacks and other limitations of the related art, the present invention provides a seat belt assembly for use in a motor vehicle to restrain a vehicle occupant. The assembly has a belt webbing extending from a first end to a second end and includes a tubular webbing section and a single panel webbing section. The tubular webbing section extends from the first end at a lower anchorage to a transition point. The solid webbing extends from the transition point to the second end. In some examples, a web stop button may be disposed on the solid webbing proximal to the transition point. The first end is attached to an anchor and is positioned in a lap belt region of the webbing and the second end is attached to a retractor spool. The tubular webbing is configured to open at a tear seam. An airbag is disposed within the tubular webbing and configured to inflate and deploy through the tear seam. A gas generator communicates with the airbag and provides expanding gas to inflate and deploy the airbag in response to a control signal. In one embodiment of the invention, a first part of the airbag is configured to inflate and deploy above the tubular webbing such that the first part of the airbag provides protection for the thorax of the occupant between a side or door of the motor vehicle and the occupant.

In another embodiment of the present invention, the assembly includes a second airbag part configured to inflate and deploy from the tubular webbing along a longitudinal length of the tubular webbing to restrain the pelvis of the occupant.

In some embodiments of this invention, the gas generator is attached to the anchor. In other embodiments, the anchor includes a tubular gas guide having at least one aperture and an internal passage. In those embodiments, the gas generator may be disposed within the internal passage of the tubular gas guide to provide a flow path for the expanding gas to enter the airbag. In one example of the gas guide, the first end of the tubular webbing includes a retaining ring. In this example, the belt webbing is attached to the anchor by axially disposing the tubular webbing through the aperture such that the ring contacts the internal passage.

In other embodiments, the gas generator is fluidly coupled to the airbag by means of a portion of the airbag being disposed through the retaining ring and into the passage of the tubular gas guide. In still other embodiments, the retaining ring is sewn into the first end of the tubular webbing, or the retaining ring may be woven into the first end of the tubular webbing. In another example, the belt webbing is woven as a unitary piece to transition from the tubular webbing to a single layer webbing at the transition point without stitching.

In still other embodiments, of the seat belt system the anchor, retractor and buckle are attached to an interior of the motor vehicle or are attached to a frame of a seat attached to the interior of the vehicle. In other examples, the shoulder potion may be guided into the retractor through a D-ring.

In yet another embodiment of the seat belt system, the latch plate may be slidably disposed along the belt webbing, or it may be fixedly disposed between the lap portion and the shoulder portion.

DETAILED DESCRIPTION OF THE INVENTION

With reference toFIGS. 1 and 2, a seat belt system10for protecting an occupant8seated in vehicle seat12is shown. The seat belt system10principally includes a seat belt assembly13having a webbing14. A first end of the webbing14attaches to a lower anchor26and extends to its second end attached to a retractor assembly36. The webbing14of the assembly13includes an upper shoulder belt portion16, and a lower lap belt portion18. The shoulder belt portion16passes around a “D” ring20of the system10. The “D” ring is typically mounted to the “B” pillar (not shown) of the motor vehicle (the vertical structural member separating the front and rear doors of a four-door vehicle). A seat belt latch plate or tongue22is attached to the seat belt webbing14and is received by a seat belt buckle24which is typically attached to the vehicle floor pan or the seat cushion frame by buckle strap24a. The embodiment shown incorporates a single spool retractor36, therefore the seat belt latch plate22slides along the webbing14. In the example shown, the anchor26, retractor36and buckle24are arranged such that the seat belt system10forms a three point configuration securing the occupant8by the lap portion18across their pelvis44and the shoulder portion16across their thorax and shoulder46.

With particular reference toFIG. 2, an isometric view of one embodiment the seat belt system10of the present invention is illustrated disassociated from the motor vehicle seat12and showing a single spool retractor assembly36. Turning to the assembly13, the lap belt portion18includes tubular webbing28and a conventional solid or single panel section31. The tubular webbing is coupled at a first end27to an anchor26, extends to a transition point29, and is configured to open at a tear seam30in response to a predetermined internal pressure. The single panel section31extends from the transition point29to the second end of the webbing14. The tubular webbing28is in fluid communication with a gas generator32attached to the anchor26. As best shown inFIG. 3, an airbag34is disposed within the tubular webbing28and is also in fluid communication with the gas generator32. The length of the tubular webbing28from the anchor26to the transition point29is constant, thereby improving the positioning of the airbag34with respect to the occupant8.

Returning toFIG. 2, the gas generator32may be activated by a control signal to provide an expanding gas to the airbag34. The expanding gas causes the airbag34to inflate and deploy through the tear seam30, rapidly expand in volume and, depending on the embodiment, provide side impact protection, reduce the contact pressure between the lap belt portion18and the occupant's pelvis44, or both (seeFIGS. 5 and 6). In addition, inflation of the airbag34may also act to pretension the webbing14in some embodiments.

In one example shown inFIG. 3, a web stop button21may be disposed on the single panel section31, proximal to the transition point29. This prevents the latch plate22from sliding onto the tubular webbing28and interfering with deployment of the airbag34. Likewise, the stop button21also prevents the tubular webbing28from sliding into and interfering with the “D” ring20when the latch plate22is disengaged from the buckle24and the webbing14is retracted by the retractor assembly36.

As illustrated inFIG. 2, the retractor assembly36is preferably disposed behind trim panels and mounted to the “B” pillar of the motor vehicle. Retractor assembly36includes a spool assembly38mounted to a frame40. Spool assembly38is connected with and stows the webbing14of the shoulder belt portion16, while the end of the lap belt portion18of the webbing14is fixedly engaged with the anchor26. The anchor26is, for example, attached to the frame40, the “B” pillar, or another portion of the motor vehicle such as the seat12. The vertically extending portion of the webbing14extending from the spool assembly38and wrapping around D-ring20is preferably positioned behind a vehicle trim panel on the B-pillar. It is also possible to implement the present invention in a so-called integrated structural seat application in which the spool retractor assembly36, D-ring20, and the anchorage for buckle24are directly carried by the structure of seat12.

Additional details of the retractor assembly36of the system10include a spool39which engages the shoulder belt portion16of the webbing14and rotates to wind-up or pay-out belt webbing14. A torsional “clock” or “motor” type spring is carried within a spring end cap42and rotationally biases the spool to retract the webbing. Spool assembly38may further incorporate other spool control mechanisms which are known in accordance with the prior art, including pretensioners, inertia and webbing sensitive locking devices or other belt control devices. “Spool control systems” referred to in this specification describes any system which controls the rotational movement of a webbing spool, thus controlling the extraction and retraction of seat belt webbing. Spool locking devices typically incorporate an inertia sensitive element, such as a rolling ball or pendulum, and cause a sprocket of the spool to be engaged to prevent further withdrawing of webbing from spool39. Webbing sensitive locking devices sense rapid pay-out of webbing to lock the retractor. Various electronic sensing mechanisms which detect the withdrawal of webbing and/or the connection of the latch plate22to the buckle24may also be incorporated into retractor assembly36. As noted above, spool assembly38is mounted to a retractor frame40.

With particular reference toFIGS. 4A-4C, as noted above the gas generator32of the assembly13is used to provide expanding gas in response to a crash or control signal and is fired or activated by electrical impulses. These impulses are generated by a vehicle restraint system controller (not shown) which receives signals from vehicle crash sensors used to detect the occurrence of a vehicle impact. Gas generator32is coupled with the tubular webbing28and gas from the gas generator32is fluidly communicated through the tubular webbing28into the airbag34.

In a first embodiment, best shown inFIG. 5, the airbag34is shaped and folded within the tubular webbing28such that upon activation of the gas generator32a first or side part33of the airbag34will inflate and deploy above and to the side of the tubular webbing28, for example, at an acute angle48relative to a horizontal plane52of the motor vehicle. This disposes the side part33between the occupant8and a door or side of the motor vehicle (not shown) to provide protection to the thorax50of the occupant8, particularly in a side impact situation. In a second embodiment, best shown inFIG. 6, the airbag34also includes a second or lap part35. The lap part35is configured and positioned within the tubular webbing28such that upon activation of the gas generator32the lap part35inflates along a longitudinal axis of the lap portion18to protect the pelvis44of the occupant8. In still another embodiment (not shown), it is possible to omit the side part33such that the airbag34only includes the lap part35and upon inflation primarily protects the pelvis44.

Returning toFIGS. 4A-4C, the anchor26of the assembly13is shown in more detail and includes a tubular gas guide54having an aperture58. An inner guide wall56of the gas guide54defines a internal passage60within which at least a portion of the gas generator32is disposed. The internal passage60provides a substantially straight flow path to guide the expanding gases generated upon activation of the gas generator32into the airbag34.

A retaining ring62having a ring outer diameter64is coupled to the first end27of the tubular webbing28. The retaining ring may be, for example, woven or stitched into the material of the first end27or attached using any other appropriate means. The internal passage60includes a primary inner diameter66that is larger than the ring outer diameter64. However, adjacent the aperture58the internal passage60includes a secondary inner diameter68. The secondary inner diameter68is smaller than the ring outer diameter64and may optionally include a lip70. As is shown inFIG. 4C, the webbing14is attached to the anchor26by disposing the tubular webbing28through the aperture58such the ring outer diameter64of the retaining ring62contacts the secondary inner diameter68or the lip70. Thus, tension applied to the webbing14is transferred through the retaining ring62into the anchor26. A portion of the airbag34is disposed through the retaining ring62and into the internal passage60and is fluidly coupled to the gas generator32