TECHNICAL FIELD

The present invention relates to a drivers side airbag device having an airbag cushion that expands and deploys between a steering wheel of a vehicle and an occupant.

BACKGROUND

Currently, nearly all vehicle steering wheels are equipped with driver's side airbag devices. The airbag cushion of the driver's side airbag device is primarily housed in the central hub of the steering wheel, and expands and deploys in front of the occupant by opening a plastic cover member or the like by the expansion pressure thereof.

With various airbag devices, a bag-like member may be provided inside an airbag cushion. For example, in the passenger seat airbag device of Patent Document 1, an inner bag41is provided inside the outer bag31for the purpose of adjusting the shape of the airbag cushion. The technology of Patent Document 1 employs an inflator21with a two-stage output, having a construction where gas is supplied to the inner bag41only when the inflator21is operated at high output. In addition, the configuration is such that when the inner bag41is inflated, a tear seam51, which is a stitched point between the inner bag41and the outer bag31, tears, and the outer bag31further expands.

RELATED ART DOCUMENTS

Patent Documents

[Patent Document 1] Japanese Unexamined Patent Application H11-321506

SUMMARY OF THE INVENTION

In addition to the technology of Patent Document 1, a diffuser, such as a bag-shaped or tubular diffuser may be provided inside the airbag cushion for the purpose of straightening gas flow, and the airbag cushion and the diffuser may be temporarily sewn in a breakable manner similar to the aforementioned tear seam51. However, in order to perform this type of temporary stitching in the mass production process of airbag devices, a special jig is required, increasing cost and labor, and also making it necessary to control quality variation. Therefore, a configuration that enables simpler temporary stitching of the airbag cushion and diffuser or the like is desirable.

Problem to be Solved by the Invention

In light of the foregoing, an object of the present invention is to provide a drivers side airbag device in which an airbag cushion and an internal diffuser can simply and temporarily be sewn together.

Means for Solving the Problem

In order to resolve the problem described above, a typical configuration of a driver's side airbag device according to the present invention includes an airbag cushion that expands and deploys between a steering wheel of a vehicle and an occupant, an inflator that supplies gas to the airbag cushion, and a diffuser that is contained in the airbag cushion and straightens gas flow from the inflator. The airbag cushion includes an occupant side panel arranged on the occupant side and a steering side panel arranged on the steering wheel side, and the diffuser includes a connecting part connected to the inflator and one or a plurality of supply ports for supplying gas received from the inflator into the airbag cushion, the one or more supply ports including an occupant side supply port that overlaps with a prescribed location of the occupant side panel of the airbag cushion with the diffuser contained therein, and the driver's side airbag device further includes a temporary stitched part that is breakably sewn between the diffuser and the prescribed location of the occupant side panel of the airbag cushion, across the occupant side supply opening of the diffuser.

With the temporary stitched part described above, connecting the diffuser to the occupant side panel can prevent the diffuser from being misaligned while stowed. In addition, use of the temporary stitched part stabilizes the occupant side panel and diffuser positions during the process of deployment of the airbag cushion. Therefore, gas can be supplied from the diffuser to the airbag cushion as set and also deployment behavior of the occupant side panel can be set for smooth expansion and deployment. The configuration described above enables mass production of airbag cushions of stable quality while improving the occupant restraint performance of the airbag cushion.

The temporary stitched part described above may be formed by a plurality of lines that intersect within the area of the occupant side supply port. This configuration of the temporary stitched part can be efficiently broken by the pressure of the gas from the occupant side supply port.

The occupant side supply port described above may be circular, and the temporary stitched part may be formed by two orthogonal lines in the center of the occupant side supply port. Even with this configuration of the temporary stitched part, the pressure of the gas from the occupant side supply port is applied evenly and thus the stitching can be efficiently broken.

A prescribed location of the occupant side panel of the airbag cushion described above may be marked with a prescribed color or pattern, and the temporary stitched part may be formed along the marking. By using the marking as a reference, the diffuser can easily be aligned with the occupant side panel, thereby improving work efficiency when forming the temporary stitched part.

The prescribed location described above of the occupant side panel may be near the center of the occupant side panel. Having the prescribed location near the center of the occupant panel is preferable as this will simplify alignment with the diffuser and simplify creation of the temporary stitched part.

Effect of the Invention

The present invention can provide a driver's side airbag device with simple temporary stitching between an airbag cushion and a diffuser contained therein.

