Steering column mounted knee airbag device

A knee airbag device mounted to a steering column of a vehicle, comprising:

• a knee airbag that is placed in a folded state within a column cover that covers a rear end portion of the steering column, and is configured to deploy toward the outside of the column cover when gas is supplied to the knee airbag;
• an inflator that is placed in the knee airbag, and is configured to supply the knee airbag with gas;
• an inner case that has flexibility and houses the folded knee airbag;
• and
• an outer member that is fixed to a lower side of a vehicle-rear-side portion of the steering column that moves relative to a vehicle-front-side portion of the steering column when a load equal to or greater than a threshold load is applied to the steering column in an axial direction of the steering column, the outer member having a rigidity with which the shape of the folded knee airbag is maintained under normal conditions, wherein
• the outer member includes:
• a mounting portion mounted to the steering column, which is placed on an upper side of the inner case;
• and
• extensions that extend forward in a longitudinal direction of the vehicle from opposite end portions of the mounting portion and are spaced from each other by a distance larger than a length of the vehicle-front-side portion as measured in the width direction of the vehicle, and
• the outer member further includes:
• front walls that are placed, in a longitudinal direction of the vehicle, on a front side of the inner case and extend downward from front ends of the extensions;
• and
• a rear wall that is placed, in a longitudinal direction of the vehicle, on a rear side of the inner case and extends downward from a rear end of the mounting portion, and wherein
• an opening is formed by the mounting portion, the extensions and the front walls and is located in a region where the outer member would interfere with the vehicle-front-side portion when the vehicle-rear-side portion moves relative to the vehicle-front-side portion.