Knee Airbag with Passive Venting for Out of Position Occupant Protection

• US 20130020788A1
• Filed: 07/18/2011
• Published: 01/24/2013
• Est. Priority Date: 07/18/2011
• Status: Active Grant

• Current Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Original Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Inventors: Spahn, Brian Robert, Rao, Manoharprasad K., Hall, Ian Brewster
• Granted Patent: US 8,590,928 B2
• Time in Patent Office: Days
• US Class Current: 280/730.1
• CPC Class Codes: B60R 2021/23107 the bag being integrated in a multi-bag system
• CPC Class Codes: B60R 2021/23169 specially adapted for knee protection
• CPC Class Codes: B60R 2021/2395 comprising means to control the venting
• CPC Class Codes: B60R 21/23 Inflatable members B60R21/18 takes precedence; connection to inflation fluid source retainers B60R21/217

Abstract

A knee airbag installed in a lower portion of an instrument panel has a deployed condition wherein it extends rearward and upward. The airbag has a left lobe, a right lobe, and a central portion between and joined to the left and right lobes. A vent is formed in the reaction surface of each of the lobes to allow inflation gasses to escape from the airbag when, during a crash event, an occupant force applied forwardly against the lobes is below a threshold level. When the occupant force reaches or exceeds the threshold level, the vents are urged against the instrument panel to substantially block the escape of inflation gasses. The threshold level is selected such that a child-sized occupant standing forward of a desired passenger seating position exerts less than the threshold level.

Claims

1. An occupant protection system for a vehicle comprising a knee airbag installed in a lower portion of an instrument panel and having a deployed condition wherein it extends rearward and upward to place a reaction surface of the airbag in contact with the instrument panel, the airbag comprising:

a left lobe, a right lobe, and a central portion disposed between and joined to the left and right lobes; and

a vent formed in each of the lobes on the reaction surface, the vents allowing inflation gasses to escape from the airbag when an occupant force directed forwardly against the lobes is below a threshold level, and the vents being urged against the instrument panel to substantially block the escape of inflation gasses when the occupant force reaches or exceeds the threshold level.

2. The apparatus of claim 1 wherein the threshold level is selected such that a child-sized occupant standing forward of a desired passenger seating position is expected to exert an occupant force less than the threshold level.

3. The apparatus of claim 1 wherein the threshold level is selected such that an adult-sized occupant seated in a desired passenger seating position and properly restrained by a seat belt is expected to exert an occupant force less than the threshold level.

4. The apparatus of claim 1 wherein a vent-bearing portion of the reaction surface immediately adjacent each vent is recessed relative to a portion of the reaction surface surrounding the vent-bearing portion, whereby the vent-bearing portion is spaced from the instrument panel when the occupant force is below the threshold level and when the occupant force reaches the threshold level the vent-bearing portion is urged against the instrument panel.

5. The apparatus of claim 1 wherein when the airbag is in an inflated state the left and right lobes are thicker than the central portion to form a valley in the central portion oriented toward the passenger.

6. The apparatus according to claim 1 wherein the left and right lobes are spaced apart from one another by a distance determined by an expected inter-knee distance of a passenger properly seated in the passenger seating position.

7. The apparatus of claim 1 wherein the knee airbag is configured to inflate the lobes prior to the inflation of the central portion.

8. The apparatus of claim 1 further comprising:

a chest airbag installed in an upper portion of an instrument panel and having a deployed condition wherein it extends rearward to contact a thorax region of a seated occupant.

9. The apparatus of claim 8 wherein the chest airbag and the knee airbag are supplied with inflation gasses by a common inflator.

10. An occupant protection system for a vehicle comprising a knee airbag installed in a lower portion of an instrument panel and having a deployed condition wherein it extends rearward and upward immediately adjacent to the instrument panel, the knee airbag comprising:

a left lobe, a right lobe, and a central portion disposed between and joined to the left and right lobes;

a vent formed in an instrument panel-facing surface of each lobe at positions such that the vents are urged against the instrument panel and substantially blocked when an occupant force directed forwardly against the lobes reaches a threshold level.

11. The apparatus of claim 10 wherein the threshold level is selected such that a child-sized occupant standing forward of a desired passenger seating position is expected to exert an occupant force less than the threshold level.

12. The apparatus of claim 10 wherein the threshold level is selected such that an adult-sized occupant seated in a desired passenger seating position and properly restrained by a seat belt is expected to exert an occupant force less than the threshold level.

13. The apparatus of claim 10 wherein a vent-bearing portion of the reaction surface immediately adjacent each vent is recessed relative to a portion of the reaction surface surrounding the vent-bearing portion, whereby the vent-bearing portion is spaced from the instrument panel when the occupant force is below the threshold level and when the occupant force reaches the threshold level the vent-bearing portion is urged against the instrument panel.

14. The apparatus of claim 10 wherein when the airbag is in an inflated state the left and right lobes are thicker than the central portion to form a valley in the central portion oriented toward the passenger.

15. The apparatus according to claim 10 wherein the left and right lobes are spaced apart from one another by a distance determined by an expected inter-knee distance of a passenger properly seated in the passenger seating position.

16. The apparatus of claim 10 wherein the airbag is configured to inflate the lobes prior to the inflation of the central portion.

17. The apparatus of claim 10 further comprising:

a chest airbag installed in an upper portion of an instrument panel and having a deployed condition wherein it extends rearward to contact a thorax region of a seated occupant.

18. The apparatus of claim 17 wherein the chest airbag and the knee airbag are supplied with inflation gasses by a common inflator.

19. A method of protecting an occupant of an automotive vehicle during a crash event comprising:

inflating a knee airbag stored in a lower portion of the instrument panel to deploy upwardly between the instrument panel and the occupant, the knee airbag having a left lobe, a right lobe, and a central portion disposed between and joined to the left and right lobes, and a vent formed in an instrument panel-facing surface of each lobe, wherein an occupant force directed forwardly against the knee airbag by the occupant during the crash event is below a threshold level required to substantially block the escape of inflation gasses by urging vents against the instrument panel.

20. The method of claim 19 wherein the threshold level is selected such that an adult-sized occupant seated in a desired passenger seating position and properly restrained by a seat belt is expected to exert less than the threshold level.