Knee-protecting airbag device

• US 20040164527A1
• Filed: 12/24/2003
• Published: 08/26/2004
• Est. Priority Date: 12/27/2002
• Status: Active Grant

• Current Assignee: Toyoda Gosei Company Limited (Toyota Motor Corporation)
• Original Assignee: Toyoda Gosei Company Limited (Toyota Motor Corporation)
• Inventors: Nagata, Atsushi, Sato, Yuji, Mizuno, Yoshio, Nakayama, Kazuhiro
• Granted Patent: US 7,201,395 B2
• Time in Patent Office: Days
• US Class Current: 280/730.1
• CPC Class Codes: B60R 2021/161 characterised by additional means for controlling deployment trajectory
• CPC Class Codes: B60R 2021/23169 specially adapted for knee protection
• CPC Class Codes: B60R 2021/23316 Inner seams, e.g. creating separate compartments or used as tethering means
• CPC Class Codes: B60R 2021/23382 Internal tether means
• CPC Class Codes: B60R 21/205 in dashboards
• CPC Class Codes: B60R 21/206 in the lower part of dashboards, e.g. for protecting the knees
• 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 21/2338 Tethers
• CPC Class Codes: B60R 21/2342 Tear seams
• CPC Class Codes: B60R 21/237 characterised by the way they are folded

Abstract

In a knee-protecting airbag device according to the present invention, an airbag folded and housed in undeployed condition protrudes rearward from a housing case to deploy upward and protects knees of a driver upon inflow of inflation gas. The airbag includes a cover portion for covering a vehicle'"'"'s rear side of an area proximate to the key cylinder upon completion of deployment, and a general portion in the upper edge side of the airbag except the cover portion. Kinetic energy of the cover portion as deployed in a position of complete deployment is restrained compared with a kinetic energy of the general portion as deployed in a position of complete deployment. This restraint is achieved by reducing amount of inflation gas flowing into the cover portion. The knee-protecting airbag device of the present invention prevents the inflating airbag from contacting with key accessories hung down from an ignition key inserted into the key cylinder in a manner to cause gas leakage.

Claims

1. A knee-protecting airbag device located below a steering column in front of a driver and, at a lower side of a key cylinder into which an ignition key with an accessory is inserted, the airbag device comprising:

a housing case located below the steering column;

an airbag folded and housed in the housing case in undeployed condition, and upon inflow of inflation gas, the airbag protruding rearward from the housing case to deploy upward for protecting knees of the driver;

the airbag comprising;

a cover portion located in a left or right corner in an upper edge side of the airbag as completely deployed for covering a vehicle'"'"'s rear side of an area proximate to the key cylinder; and

a general portion being the upper edge side of the airbag completely deployed except the cover portion; and

a damage prevention means for preventing the airbag from being damaged by the key accessory and leaking gas when the inflated airbag contacts with the key accessory directly.

2. The knee-protecting airbag device according to claim 1, wherein:

the damage prevention means constitutes a restraining means to restrain a kinetic energy of the cover portion of the airbag as deployed in a position of complete deployment compared with a kinetic energy of the general portion as deployed in a position of complete deployment; and

the airbag is housed in the housing case while being equipped with the restraining means.

3. The knee-protecting airbag device according to claim 2, wherein the restraining means functions as a gas-flow regulating means to regulate flow of inflation gas.

4. The knee-protecting airbag device according to claim 3, wherein:

the airbag as completely inflated takes a substantially plate shape including a column side wall located toward the steering column and a driver'"'"'s side wall located toward the driver;

the airbag internally comprises a tether joining the column side wall and the driver'"'"'s side wall for regulating thickness of the airbag as completely inflated; and

the tether constitutes the gas-flow regulating means to slow down a flow speed of inflation gas flowing into the cover portion than a flow speed of inflation gas flowing into the general portion.

5. The knee-protecting airbag device according to claim 3, wherein:

the airbag as completely inflated takes a substantially plate shape including a column side wall located toward the steering column and a driver'"'"'s side wall located toward the driver;

the airbag internally comprises a tether joining the column side wall and the driver'"'"'s side wall for regulating thickness of the airbag as completely inflated;

the tether is located upstream of inflation gas below the general portion and the cover portion of the completely inflated airbag transversely;

the general portion and the cover portion have gas inlet ports, respectively, between left and right ends of the tether and inner surface of the airbag in the transverse direction;

in a folding process of the airbag, when at least one of the left and right edge side of the airbag is folded toward center of the airbag on folds along vertical direction, the vertical fold toward the cover portion is formed to cross the tether while the vertical fold toward the general portion is formed away from the tether,

whereby the vertical fold crossing the tether toward the cover portion constitutes the gas-flow regulating means.

6. The knee-protecting airbag device according to claim 3, wherein:

the airbag further internally comprises an inflator for supplying inflation gas; and

the inflator constitutes the gas-flow regulating means to discharge more inflation gas toward the general portion than toward the cover portion.

7. The knee-protecting airbag device according to claim 3, wherein the cover portion itself constitutes the gas-flow regulating means by being formed to have greater thickness, as completely inflated, than the general portion.

8. The knee-protecting airbag device according to claim 2, wherein the restraining means is constituted by an airbag folding process that delays unfolding of the cover portion than the general portion when the general portion and the cover portion are unfolded in the course of airbag deployment.

9. The knee-protecting airbag device according to claim 2, wherein the restraining means is constituted by a fold-keeping member that keeps the folded state of the cover portion in a releasable manner, whereby the cover portion is unfolded later than the general portion when the general portion and the cover portion are unfolded in the course of airbag deployment.

10. The knee-protecting airbag device according to claim 1, wherein:

the airbag as completely inflated takes a substantially plate shape comprising a column side wall located toward the steering column and a driver'"'"'s side wall located toward the driver;

folding process of the airbag for housing the airbag in the housing case comprises a roll-folding step in which, from flat state in which the column side wall and the driver'"'"'s side wall are overlaid on each other, the upper edge side of the airbag is roll-folded on the column side wall toward the lower edge side, and a cover-portion folding step to fold a corner of the cover portion toward the transverse center of the airbag; and

the damage prevention means is constituted by a series of processes that the cover-portion folding is performed before the roll-folding step, and then the airbag is housed in the case.

11. The knee-protecting airbag device according to claim 10, wherein the cover portion is folded on the driver'"'"'s side wall in the cover-portion folding step.

12. The knee-protecting airbag device according to claim 1, wherein:

the airbag comprises a primary inflatable portion, the primary inflatable portion being inflatable from initial stage of inflow of inflation gas, and including the general portion as a part thereof, and a secondary inflatable portion, the secondary inflatable portion starting to inflate around when the primary inflatable portion completes inflation,

the cover portion is located either in an area of the secondary inflatable portion of the airbag, or in an area near the secondary inflatable portion, whereby constituting the damage prevention means.

13. The knee-protecting airbag device according to claim 12, wherein:

the airbag as completely inflated takes a substantially plate shape including a column side wall located toward the steering column and a driver'"'"'s side wall located toward the driver; and

the primary inflatable portion and the secondary inflatable portion are formed by stitching yarn, the stitching yarn breakably stitching the column cover side wall and the driver'"'"'s side wall together.

14. A knee-protecting airbag device located below a steering column in front of a driver and, at a lower side of a key cylinder into which an ignition key with an accessory is inserted, the airbag device comprising:

a housing case located below the steering column;

an airbag folded and housed in the housing case in undeployed condition, and upon inflow of inflation gas, the airbag protruding rearward from the housing case to deploy upward for protecting knees of the driver, the airbag comprising a cover portion located in a left or right corner in an upper edge side of the airbag as completely deployed for covering a vehicle'"'"'s rear side of an area proximate to the key cylinder; and

a damage prevention member located in the periphery of the key cylinder for preventing the airbag from contacting with the key accessory in a manner to cause gas leakage.

15. The knee-protecting airbag device according to claim 14, wherein:

the damage prevention member is located to encircle the lower side of the key cylinder; and

the damage prevention member comprises

a receiving plane extended from a leading end plane of the key cylinder for receiving the key accessory hung down from the key from lower side, and

a guide plane extended downward from the rear end of the receiving plane for guiding the inflating airbag upward.

16. The knee-protecting airbag device according to claim 14, wherein the damage prevention member is protruded from periphery of the key accessory below the key accessories, a lower surface of the damage prevention member functioning as a guide surface to guide the inflating airbag upward.

17. The knee-protecting airbag device according to claim 14, wherein the damage prevention member is located at least one of the left or right side of the key accessory, the member protruding rearward of the vehicle than the key accessory, and a lower surface of the damage prevention member functioning as a guide surface to guide the inflating airbag upward.

18. The knee-protecting airbag device according to claim 17, wherein the damage prevention member is supported by a moving means movably between a preventing position where the damage prevention member prevents the damage of the airbag and a housed position where the member is housed in the periphery of the key cylinder.

19. The knee-protecting airbag device according to claim 18, wherein the moving means is actuated to protrude the damage prevention member up to the preventing position when a parking brake is released after a vehicle engine is started, and is actuated to return the damage prevention member to the housed position when the parking brake is applied.

20. The knee-protecting airbag device according to claim 14, wherein the damage prevention member prevents the inflating airbag from contacting with the key accessory by moving the key accessory.