Airbag for knee protection

• US 20090085333A1
• Filed: 09/18/2008
• Published: 04/02/2009
• Est. Priority Date: 09/27/2007
• Status: Abandoned Application

• Current Assignee: Toyoda Gosei Company Limited (Toyota Motor Corporation)
• Original Assignee: Toyoda Gosei Company Limited (Toyota Motor Corporation)
• Inventors: Imaeda, Hiroki, Sakakida, Katsumi
• Application Number:
  US12/232,544
• Publication Number:
  US 20090085333A1
• Time in Patent Office: Days
• US Class Current: 280/730.100
• CPC Class Codes: B60R 2021/23169 specially adapted for knee protection
• CPC Class Codes: B60R 2021/23324 Inner walls crating separate compartments, e.g. communicating with vents
• CPC Class Codes: B60R 2021/23509 Fabric
• CPC Class Codes: B60R 21/2032 the inflator or inflatable member not being rotatable with the steering wheel; Arrangements using the steering column or steering wheel rim for storing, supplying or evacuating the inflation gas or for storing the inflatable member
• CPC Class Codes: B60R 21/206 in the lower part of dashboards, e.g. for protecting the knees
• CPC Class Codes: B60R 21/2165 characterised by a tear line for defining a deployment opening
• CPC Class Codes: B60R 21/2171 specially adapted for elongated cylindrical or bottle-like inflators with a symmetry axis perpendicular to the main direction of bag deployment, e.g. extruded reaction canisters B60R21/2176 takes precedence
• CPC Class Codes: B60R 21/231 characterised by their shape, construction or spatial configuration
• CPC Class Codes: B60R 21/237 characterised by the way they are folded

Abstract

An airbag for knee protection internally includes a first tether that connects a knee-side wall and a vehicle body side wall by a connecting distance of 50 to 90 mm and partitions the airbag into an upper inflatable chamber and a lower inflatable chamber. The mainstreams of inflation gas heading to the upper inflatable chamber from the lower are located proximate left and right ends of the airbag. The upper inflatable chamber has an outer diameter of 150 to 220 mm at full airbag inflation. The lower inflatable chamber includes on the vehicle body side wall a mounting portion by which the airbag is secured to the case and is designed such that a top of its rear face is dislocated forward relative to that of the upper inflatable chamber by 10 to 70 mm at full inflation of the airbag.

Claims

1. An airbag for knee protection adapted to be mounted on a low location in front of a seat of vehicle in a folded-up state inside a case having an emergence opening oriented rearward for emergence from the emergence opening and deployment upward and rearward to protect knees of a vehicle occupant when fed with inflation gas, the airbag comprising:

an outer wall having a planar bag shape comprising a knee-side wall for deployment toward the seat and a vehicle body side wall continuing from an outer edge of the knee-side wall for deployment in front of and facing the knee-side wall, the knee-side wall and the vehicle body side wall having same outer contours as are flattened and being formed of base cloths having a Frazier air permeability of 0.6 L/cm²/min and below;

an upper inflatable chamber having a generally columnar contour that extends in a transverse direction and has an outer diameter of 150 to 220 mm when the airbag is fully inflated vertically by itself, the upper inflatable chamber acting as a knee-arresting portion for receiving entire front faces of knees to the vicinity of upper ends of shins of the occupant upon airbag deployment;

a lower inflatable chamber located below the upper inflatable chamber and having a smaller volume and thickness than the upper inflatable chamber at full inflation of the airbag, the lower inflatable chamber including on the vehicle body side wall a mounting portion for attachment of the airbag to the case and being designed such that a top of a rear face of the lower inflatable chamber projecting rearward in a thickness direction of the airbag is dislocated forward relative to a top of a rear face of the upper inflatable chamber by 10 to 70 mm when the airbag is fully inflated vertically by itself;

a first tether extending horizontally inside the airbag, the first tether connecting the knee-side wall and vehicle body side wall together by a connecting distance of 50 to 90 mm for controlling a thickness of the airbag in an opposing direction of the knee-side wall and vehicle body side wall upon airbag deployment and partitioning the upper inflatable chamber and lower inflatable chamber, the first tether being located at a location to defect from the case at full deployment of the airbag; and

a plurality of gas communication holes formed at a location of the first tether for communicating the upper inflatable chamber and lower inflatable chamber, the gas communication holes being configured such that mainstreams of inflation gas heading to the upper inflatable chamber from the lower inflatable chamber are located proximate both left and right ends of the airbag so the upper inflatable chamber inflates from left and right regions to the center.

2. The airbag for knee protection of claim 1 wherein the base cloths are made of woven fabric having no coating for preventing gas leakage.

3. The airbag for knee protection of claim 1 wherein the gas communication holes includes:

a center hole located proximate a center of the airbag in a transverse direction; and

each one end hole located proximate left and right ends of the airbag, each of which end holes having a greater opening area than the center hole.

4. The airbag for knee protection of claim 3 wherein:

the gas communication holes includes a plurality of the center holes disposed side by side along the transverse direction; and

a distance between a leftmost center hole and a rightmost center hole is greater than a transverse width of the emergence opening of the case.

5. The airbag for knee protection of claim 1 further comprising in the upper inflatable chamber a second tether that is connected to a joint of a front end of the first tether to the vehicle body side wall by a front end and connected to the vicinity of a vertically intermediate position between an upper end of the knee-side wall of the upper inflatable chamber and a joint of the first tether to the knee-side wall and at least in the vicinity of a center of the knee-side wall of the upper inflatable chamber in the transverse direction by a rear end such that, at airbag inflation, an area around a joint of the second tether to the knee-side wall of the upper inflatable chamber is located forward relative to a hypothetical top of the rear face of the upper inflatable chamber in a hypothetical configuration where the airbag has no said second tether.

6. The airbag for knee protection of claim 5 wherein the second tether is configured such that the rear face of the upper inflatable chamber is partially located forward by 5 to 40 mm at full inflation of the airbag relative to that in the hypothetical configuration where the airbag has no said second tether.

7. The airbag for knee protection of claim 5 wherein:

the airbag is a cut-and-sewn airbag that is formed by sewing a plurality of base cloths together; and

the front ends of the first tether and the second tether are sewn to the vehicle body side wall by a same, single seam.

8. The airbag for knee protection of claim 5 wherein the second tether is integral with a base cloth for forming the vehicle body side wall of the lower inflatable chamber.

9. The airbag for knee protection of claim 5 wherein a width of the second tether in the transverse direction is smaller than an assumed distance between knees of the occupant.