Mounting structure of driver airbag unit, and steering wheel

1. A mounting structure of a driver airbag unit comprising:

a steering wheel; and

the driver airbag unit attached to the steering wheel so as to move at least toward and away from a driver, said driver airbag unit including

an airbag including a folded body,

an inflator for expanding the airbag,

a retainer to which the airbag and the inflator are attached,

a module cover attached to a driver-side face of the retainer, so as to cover the folded body of the airbag,

a leg member projecting from the retainer in a direction away from the driver to connect to the steering wheel,

a biasing member arranged between the steering wheel and the retainer such that the retainer is biased toward the driver, and

an electric circuit operated when the driver airbag unit is pressed by the driver and displaced away from the driver,

wherein the retainer includes a leg insertion hole; and the leg member is formed separately from the retainer, and inserted from a side of the driver through the leg insertion hole formed in the retainer such that the retainer moves at least toward and away from the driver along the leg member,

the module cover includes a main surface portion covering a driver-side face of the folded body of the airbag; and a wall portion projecting from the main surface portion in the direction away from the driver, and

the leg member includes a pair of guide plates projecting toward the driver, and the wall portion is inserted between the pair of guide plates so as to move at least away from and toward the driver along the pair of guide plates.

2. The mounting structure of the driver airbag unit according to claim 1 ,

wherein the leg member includes a main leg portion inserted through the leg insertion hole; and a stopper portion protruding in a lateral direction from a face of the main leg portion on the side of the driver, and

the stopper portion restricts the retainer from moving farther away from the steering wheel, upon being abutted to the retainer from the side of the driver.

3. The mounting structure of the driver airbag unit according to claim 1 ,

wherein one of the pair of guide plates includes a positioning projection projecting toward another of the pair of guide plates,

the wall portion includes a positioning slot with which the positioning projection is engaged so as to move at least away from and toward the driver, and

the module cover is positioned with respect to the steering wheel when the positioning projection is engaged with an edge of the positioning slot opposite to the driver, while the module cover is free from a pressure from the side of the driver.

4. The mounting structure of the driver airbag unit according to claim 3 ,

wherein the positioning projection has a tapered shape in which a width in a direction orthogonal to a projecting direction of the positioning projection from the one of the pair of guide plates and a direction from the driver toward an opposite side of the driver becomes narrower toward the opposite side of the driver, and

the positioning slot has a tapered shape in which a width in the direction orthogonal to the projecting direction of the positioning projection from the one of the pair of guide plates and the direction from the driver toward the opposite side of the driver becomes narrower toward the opposite side of the driver.

5. The mounting structure of the driver airbag unit according to claim 1 , wherein the steering wheel includes a steering wheel-side contact formed on an upper end portion thereof and the retainer includes airbag unit-side contact formed at a lower end portion thereof to face the steering wheel-side contact, and when the steering wheel-side contact contacts the airbag unit-side contact, the electric circuit is operated.