Patent Description:
Airbag devices have generally become standard equipment in vehicles in recent years. An airbag device is a safety device which is operated in the event of an emergency such as a vehicle collision, retaining and protecting passengers utilizing an airbag cushion which expands and deploys based on gas pressure. Prior to expansion and deployment, the airbag cushion is folded or rolled into a small, stowed form for installation in various places in a vehicle.

For example, patent Document <NUM> discloses a knee protection airbag device including an airbag that is folded and stowed on a lower surface side of a column cover covering a steering column and an inflator that supplies inflation gas to the airbag. In the knee protection airbag device of Patent Document <NUM>, an airbag into which the expansion gas discharged from the inflator flows protrudes from the stowed site on the lower surface side of the column cover, and expands and deploys so as to cover the lower surface side of the column cover. This enables protecting both knees of the driver. Patent Document <NUM> relates to a driver's side airbag module. Patent Document <NUM> relates to a knee impact protection device for a motor vehicle. Patent Document <NUM> relates to a gas bag module for a vehicle occupant restraint system. Patent Document <NUM> relates to an airbag module for a vehicle occupant restraint system. Patent Document <NUM> relates to a gas bag module for a vehicle occupant restraint system.

Patent Document <NUM>: <CIT> ; Patent Document <NUM>: <CIT> ; Patent Document <NUM>: <CIT> ; Patent Document <NUM>: <CIT> ; Patent Document <NUM>: <CIT> ; Patent Document <NUM>: <CIT>.

In an emergency, an airbag needs to rapidly expand and deploy. However, if the housing does not readily open, the expansion and deployment of the airbag will be hindered, and expanding and deploying an airbag at the desired timing will be difficult. Therefore, there has been a demand for the development of technology enabling housing to open more readily.

In light of these issues, an object of the present invention is to provide an airbag module where the housing opens readily during expansion and deployment of the airbag.

To resolve the problems described above, a typical configuration of an airbag module according to the present invention is defined in claim <NUM>. The airbag module includes:.

With the configuration described above, the pair of side walls of the housing are separated by the expanding and deploying airbag cushion. As a result, the opening on the upper side of the housing opens up. Therefore, when the airbag cushion expands, the airbag cushion can be easily deployed to the outside through the opening of the housing. As the housing opens readily in this manner, the speed of airbag cushion deployment can be increased. As a result, the deployment behavior is stable and the occupant can be restrained more quickly, so that occupant injury value can be reduced. In addition, the housing opening readily improves resistance of internal pressure reduction of the cushion during airbag cushion deployment. Therefore, the amount of cushion base material is anticipated to be reduced and the housing plate thickness is anticipated to be reduced enabling potential cost reduction.

Here, if a cover is used to cover the opening of the housing, the pair of side walls of the housing will separate before the airbag cushion breaks the cover and expands and deploys to the outside, especially when the height of the housing is high. Therefore, only deformation of the housing occurs, and deployment of the airbag cushion may be delayed.

Therefore, in the configuration described above, the cover is provided with a first weak portion extending in the longitudinal direction of the upper surface portion of the housing. This causes the cover to cleave at the first weak portion as the airbag cushion expands and deploys. Therefore, the airbag cushion can efficiently be expanded and deployed to the outside from the first weak portion that has been cleaved. Therefore, the airbag cushion can be rapidly expanded and deployed.

The convex polygonal shape described above is preferably a quadrangular shape. The aforementioned effect can be obtained by this manner of configuration as well. The "convex polygon" is in plan view, a polygon surrounded by three or more straight lines or curved line segments, where the inside angle of all of the angles is smaller than two right angles. Further, the cross-sectional view is defined as a plane observed in a plane orthogonal to the vertical direction from above or below.

The portion of the cover that covers the mutually opposed second pair of side surfaces of the housing is formed with second weak portions respectively extending downward from both ends of the first weak portion that are weaker than the area surrounding thereof and cleave subsequent to cleaving of the first weak portion.

With the configuration described above, the second weak portion of the cover also cleaves during expansion and deployment of the airbag cushion. As a result, the opening of the cover when the airbag cushion expands and deploys can be opened wider. Therefore, the effects as described above can be enhanced.

The direction in cross-section view of the second pair of side surfaces extending in the longitudinal direction intersects with the direction in cross-section view of the first pair of side surfaces extending in the longitudinal direction.

The cover described above may include a third weak portion that extends along the boundary of the portion that covers the opening of the housing and the portion that covers the second pair of side surfaces of the housing, that is weaker than the surrounding area thereof, and is cleaved subsequent to the first weak portion cleaving. With this manner of configuration, the cover is cleaved in the first weak portion and the third weak portion. As a result, the opening of the cover can be further widened, and the airbag cushion can be expanded and deployed more quickly.

The present invention enables providing an airbag module with the housing readily capable of opening when the airbag expands and deploys.

Preferred embodiments according to the present invention will hereinafter be described in detail with reference to the attached drawings. Dimensions, materials, other specific numerical values, and the like indicated in the embodiments are merely examples for ease of understanding of the invention and do not limit the present invention unless otherwise noted. Note that in the present specification and drawings, elements having essentially identical functions and configurations are labeled with identical symbols in order to omit redundant descriptions along with an illustration of elements not directly related to the present invention. In the drawings used in the following description, the upper and lower parts are referred to as "Up" and "Down".

<FIG> is a perspective view of the airbag module <NUM> according to Embodiment <NUM> of the present invention. For ease of understanding, <FIG> schematically illustrates a housing <NUM>, an airbag cushion <NUM>, and an inflator <NUM> of the airbag module <NUM>.

As illustrated in <FIG>, the airbag module <NUM> includes the housing <NUM>. The folded or wound airbag cushion <NUM> is stowed inside the housing <NUM>. The inflator <NUM> is installed in the airbag cushion <NUM>.

The cross-section of the housing <NUM> is a quadrangular shape and the upper part is an opening 410a. When the airbag cushion <NUM> expands and deploys, of the four side surfaces 412a, 412b, 414a, and 414b of the housing <NUM>, the first pair of side surfaces 412a, 412b facing each other expand so as to be separated from each other in the Ar1 direction, deforming the housing <NUM>. As a result, the opening 410a on the upper side of the housing <NUM> opens up. When the airbag cushion <NUM> expands, the airbag cushion <NUM> can be easily deployed to the outside through the opening 410a of the housing <NUM>.

As the housing <NUM> opens readily in this manner, speed of deployment of the airbag cushion <NUM> can be increased. As a result, the deployment behavior is stable and the occupant can be restrained more quickly, so that occupant injury value can be reduced. In addition, the housing <NUM> opening readily provides an improvement in cushion resistance, reducing internal pressure during deployment of the airbag cushion <NUM>. Therefore, the amount of cushion base material is anticipated to be reduced and the plate thickness of the housing <NUM> is anticipated to be reduced, enabling potential cost reduction.

Note that <FIG> illustrates the housing <NUM> having a quadrangular shape in cross-section view, but the present invention is not limited to this. Even if the housing <NUM> has a convex polygonal shape other than a quadrangular shape, the same effect as described above can be obtained.

And as illustrated in <FIG>, the airbag module <NUM> of Embodiment <NUM> further includes a cover <NUM> that covers the opening 410a and the four side surfaces 412a, 412b, 414a, and 414b of the housing <NUM>. The cover <NUM> has an upper surface portion 440a covering the opening 410a of the housing <NUM> and four opposing surfaces 442a, 442b, 444a, 444b that oppose the four side surfaces 412a, 412b, 414a, 414b of the housing <NUM>.

As a feature of Embodiment <NUM>, the cover <NUM> is formed with a first weak portion <NUM> and second weak portions 464a and 464b. The first weak portion <NUM> is formed in the upper surface portion 440a, which is a portion of the cover <NUM> that covers the opening 410a of the housing <NUM>, and extends in the longitudinal direction of the upper surface portion 440a. The first weak portion <NUM> is weaker than the area surrounding thereof and is cleaved by the separation of the first pair of side surfaces 412a and 412b.

The second weak portions 464a and 464b are formed on the opposing surfaces 444a and 444b, which are the portions of the cover <NUM> that cover the mutually opposed second pair of side surfaces 414a and 414b of the housing <NUM>, and continuously extend lower respectively from both ends of the first weak portion <NUM>. The second weak portions 464a and 464b are weaker than the area surrounding thereof, and cleave following the cleavage of the first weak portion <NUM>.

Providing the cover <NUM> with a first weak portion <NUM> as described above enables the cover <NUM> to cleave at the first weak portion <NUM> when the airbag cushion <NUM> expands and deploys. Therefore, the airbag cushion <NUM> can efficiently be expanded and deployed to the outside from the first weak portion <NUM> that has been cleaved. As a result, the airbag cushion <NUM> can be expanded and deployed more quickly and reliably than when a cover having no weak portion is used.

In addition, with the airbag module <NUM> of the present embodiment, the cover <NUM> is provided with the second weak portions 464a and 464b. Thus, the cover <NUM> also cleaves at the second weak portions 464a and 464b when the airbag cushion <NUM> expands and deploys. Therefore, the opening of the cover <NUM> when the airbag cushion <NUM> expands and deploys can be opened wider. Therefore, the airbag cushion <NUM> can be expanded and deployed to the outside more quickly and reliably. The direction in cross-section view of the second pair of side surfaces 414a and 414b extending in the longitudinal direction intersects with the direction in cross-section view of the first pair of side surfaces 412a and 412b extending in the longitudinal direction.

<FIG> is a schematic cross-sectional view taken along the line A-A of the cover <NUM> of <FIG>. As illustrated in <FIG>, rather than the first pair of side surfaces 412a and 412b that separate when the airbag cushion <NUM> expands and deploys, the cover <NUM> is provided with hinges 446a and 446b on the opposing surfaces 444a and 444b that are opposite the second pair of side surfaces 414a and 414b. Furthermore, straps 450a and 450b are engaged with hooks 448a and 448b and hooks 448c and 448d securing the hinges 446a and 446b to the opposing surfaces 444a and 444b.

With the configuration described above, even if the cover <NUM> is split into two due to cleavage of the first weak portion <NUM> and the second weak portions 464a and 464b, movement of the split cover <NUM> is restricted by the straps 450a and 450b. Therefore, scattering of the split cover <NUM> can be prevented.

<FIG> is a diagram describing Embodiment <NUM> of the cover. With the cover <NUM> of Embodiment <NUM>, the first weak portion <NUM> was formed on the upper surface portion 440a, and the second weak portions 464a and 464b were formed on the pair of opposing surfaces 444a and 444b. On the other hand, with the cover <NUM> illustrated in <FIG>, third weak portions 466a and 466b are formed in addition to the first weak portion <NUM> and second weak portions 464a and 464b.

The third weak portions 466a and 466b are the portions that cover the opening 410a of the housing <NUM> (see <FIG>) that extend along the boundaries of the upper surface portion 440a and the opposing surfaces 444a and 444b that are the portions that cover the second pair of side surfaces 414a and 414b of the housing <NUM> (see <FIG>). The third weak portions 466a and 466b are weaker than the areas surrounding thereof and cleave subsequent to cleaving of the first weak portion <NUM>.

With this manner of configuration, the cover <NUM> is cleaved at the third weak portions 466a and 466b in addition to the first weak portion <NUM> and the second weak portions 464a and 464b when the airbag cushion <NUM> expands and deploys. As a result, the opening of the cover <NUM> can be further widened, and the airbag cushion <NUM> can be expanded and deployed more quickly.

<FIG> is a diagram describing Embodiment <NUM> of the cover which is not part of the present invention. With the cover <NUM> of Embodiment <NUM>, the first weak portion <NUM> was formed on the upper surface portion 440a, and the second weak portions 464a and 464b were formed on the pair of opposing surfaces 444a and 444b. On the other hand, with a cover <NUM> illustrated in <FIG>, only the first weak portion <NUM> is formed.

With the configuration described above, cleaving of the opposing surfaces 444a and 444b due to the second weak portions 464a and 464b does not occur but the upper surface portion 440a is cleaved by the first weak portion <NUM>. Therefore, the effect of the airbag cushion <NUM> expanding and deploying externally from the first weak portion <NUM> cleavage location is achieved. Note, if a first weak portion <NUM> is formed as with the cover <NUM> illustrated in <FIG>, the cover <NUM> having an upper surface portion 440a is sufficient and having opposing surfaces 442a, 442b, 444a, and 444b is not absolutely necessary.

Next, a housing structure applicable to the housing <NUM> illustrated in <FIG> will be described. <FIG> is a perspective view illustrating a first housing structure <NUM>. <FIG> is an overall perspective view of the first housing structure <NUM>. <FIG> is a perspective view of the first housing structure <NUM> of <FIG> observed from a different direction. <FIG> is a schematic cross-sectional view of the leg part of <FIG> taken along the line A-A. For ease of understanding, <FIG> illustrates an airbag cushion <NUM> and an inflator <NUM> not shown in <FIG> as dashed lines.

As illustrated in <FIG>, the first housing structure <NUM> is quadrangular and has a first member <NUM> and a second member <NUM>. The first member <NUM> has three side walls 130a, 130b, and 130c. The second member <NUM> includes three side walls 140a, 140b, and 140c that are opposite the first member <NUM> and overlap inside the first member <NUM>.

As illustrated in <FIG>, leg parts <NUM> and <NUM> extend from bottom walls <NUM> and <NUM> of the first member <NUM> and the second member <NUM> respectively. The first housing structure <NUM> is secured with the leg parts <NUM> and <NUM> to the frame <NUM> by a bolt <NUM> and a nut <NUM>. In the first housing structure <NUM>, the bolt <NUM> connects the first member <NUM> and the second member <NUM>, and serves as a rotation axis for relative rotation thereof.

As illustrated in <FIG>, in Embodiment <NUM>, the housing <NUM> is provided with a pin <NUM> and a bracket <NUM> as a member for guiding the rotation of the first member <NUM> and the second member <NUM>. The pin <NUM> is secured to the first member <NUM>. The bracket <NUM> is arc-shaped and is secured to the second member <NUM>. An arc-shaped slot 164a in which the pin <NUM> is slidably inserted is formed in the bracket <NUM>.

<FIG> is a diagram describing the behavior of the first housing structure <NUM> of <FIG> during expansion and deployment of the airbag cushion <NUM>. Prior to expansion and deployment of the airbag cushion <NUM>, the pin <NUM> is positioned at start point P1 of the bracket <NUM> slot 164a as illustrated in <FIG>. Furthermore, when the airbag cushion <NUM> expands and deploys, the first member <NUM> is pushed out by the pressure thereof. Thus, the pin <NUM> moves in the slot 164a of the bracket <NUM> and the first member <NUM> rotates relative to the second member <NUM> around a rotational axis (bolt <NUM>). Furthermore, as illustrated in <FIG>, the pin <NUM> moves to the end point P2 of the slot 164a and the opening <NUM> of the upper side of the case type first housing structure <NUM> opens up.

With the configuration described above, rotation of the first member <NUM> with respect to the second member <NUM> causes the opening on the upper part of the first housing structure <NUM> to open up. In other words, the opening of the first housing structure <NUM> readily opens during expansion and deployment of the airbag cushion <NUM>. As the first housing structure <NUM> opens readily in this manner, speed of the airbag cushion deployment can be increased.

Also, with the configuration described above, the pin <NUM> and the bracket <NUM> are provided to enable guiding the rotation of the first member <NUM> relative to the second member <NUM> in the first housing structure <NUM>. Thus, stable operation is feasible and the desired behavior can be reliably obtained.

Furthermore, with the present embodiment, as illustrated in <FIG>, the first housing structure <NUM> includes bearings <NUM> that are connected to the bolt <NUM> as a rotation axis. Therefore, friction of the bolt <NUM> when the first member <NUM> rotates relative to the second member <NUM> can be reduced. Therefore, since the first member <NUM> and the second member <NUM> rotate more smoothly, the effects described above can be improved.

<FIG> is a perspective view describing a second housing structure <NUM>. As illustrated in <FIG>, the housing structure <NUM> includes four side walls, a side wall <NUM>, side wall <NUM>, side wall <NUM>, and side wall <NUM>, with the upper part thereof being an opening 210a, and two extendable walls 220a and 220b. The two extendable walls 220a and 220b connect one side wall <NUM> to two side walls <NUM> and <NUM> located on both sides thereof. As illustrated in <FIG>, the two extendable walls 220a and 220b are in a folded state before the airbag cushion <NUM> (see <FIG>) expands and deploys.

<FIG> is a perspective view illustrating a state in which the extendable walls 220a and 220b of the housing structure <NUM> of <FIG> are opened up. As illustrated in <FIG>, the two extendable walls 220a and 220b open up in this manner when the airbag cushion <NUM> (see <FIG>) expands and deploys. Thus, the opening 210a of the upper part of the four side walls <NUM>, <NUM>, <NUM>, and <NUM> opens up.

With the configuration described above, the opening 210a of the housing structure <NUM> more readily opens when the airbag cushion <NUM> expands and deploys. Thus, the deployment speed of the airbag cushion <NUM> can be increased, and deployment behavior is stabilized. Therefore, since the occupant can be restrained more quickly, the occupant injury value can be reduced.

In particular, with the second housing structure <NUM> illustrated in <FIG>, the two extendable walls 220a and 220b have a triangular shape. Since the two extendable walls 220a and 220b have symmetrical shapes, the extendable wall 220a will be used as representative of the walls and will be described in detail below.

As illustrated in <FIG>, the extendable wall 220a has a first side <NUM> along the edge of the side wall <NUM>, a second side <NUM> along the edge of the side wall <NUM>, and a third side <NUM> that connects the upper ends of the first side <NUM> and second side <NUM>, composing a triangular shape.

In the configuration described above, the two extendable walls 220a and 220b have a triangular shape with a width that increases toward the top. As a result, when the two extendable walls 220a and 220b open up during the expansion and deployment of the airbag cushion <NUM>, the opening 210a of the housing structure <NUM> widens toward the top. This enables further increase in the deployment speed of the airbag cushion <NUM>.

<FIG> is a perspective view illustrating a third housing structure <NUM>. <FIG> is an overall perspective view of the third housing structure <NUM>. <FIG> is a perspective view of the third housing structure <NUM> of <FIG> observed from a different direction. <FIG> is an expanded perspective view of the vicinity of a connecting member <NUM> in <FIG>.

As illustrated in <FIG>, the third housing structure <NUM> includes a first member <NUM> and a second member <NUM>. The first member <NUM> has three side walls 330a, 330b, and 330c. The second member <NUM> has three side walls 340a, 340b, and 340c, and is arranged inside the first member <NUM>. The first member <NUM> and second member <NUM> are connected by the connecting member <NUM>.

As illustrated in <FIG> and <FIG>, the connecting member <NUM> includes a first connecting member <NUM> and a second connecting member <NUM>. The first connecting member <NUM> includes a joint part <NUM>, a connecting part <NUM>, and a bending part <NUM>. The joint part <NUM> is the location for joining with the first member <NUM> and the connecting part <NUM> is the location for connecting to the second connecting member <NUM>. The bending part <NUM> that is a bending location is formed between the joint part <NUM> and the connecting part <NUM>.

The second connecting member <NUM> includes a joint part <NUM>, a connecting part <NUM>, and a bending part <NUM>. The joint part <NUM> is the location for joining with the second member <NUM> and the connecting part <NUM> is the location for connecting to the first connecting member <NUM>. A bending part <NUM> that is the bending portion that is separated from the first member or the second member is formed between the joint part <NUM> and the connecting part <NUM>.

The connecting portion <NUM> of the first connecting member <NUM> and connecting portion <NUM> of the second connecting member <NUM> are secured by a bolt <NUM> illustrated in <FIG> and a nut <NUM> illustrated in <FIG>. Thus, the first member <NUM> and second member <NUM> are connected by means of the first connecting member <NUM> and second connecting member <NUM>.

With the configuration described above, upon expansion and deployment of the airbag cushion <NUM> (see <FIG>), the pressure thereof causes the bending parts <NUM> and <NUM> that are the bent portions of the connecting member <NUM> to extend in the directions of the arrows D2 and D3 illustrated in <FIG>. Thus, the first member <NUM> separates from the second member <NUM> in the direction of the arrow D1 illustrated in <FIG> causing an opening 310a (see <FIG>) of the upper part of the third housing structure <NUM> to open.

Note, in the present embodiment, a configuration using two connecting members (first connecting member <NUM> and second connecting member <NUM>) was illustrated but the configuration is not limited to this. For example, if the connecting part <NUM> of the first connecting member <NUM> is connected to the second member <NUM>, the effect described above can be achieved without requiring the second connecting member <NUM>.

<FIG> is a diagram illustrating a vehicle equipped with the airbag module of the present embodiment. <FIG> illustrates an example of a motorcycle <NUM> as a vehicle, and the airbag module <NUM> of Embodiment <NUM> as an airbag module mounted on the motorcycle <NUM>. However, the vehicle is not limited to the motorcycle as a matter of course, and may be a four-wheeled vehicle, and the airbag module to be mounted may also use the airbag module of another embodiment.

As illustrated in <FIG>, the airbag module <NUM> is mounted on the front portion of the motorcycle <NUM>, that is, in front of the occupant P. The folded or rolled airbag cushion <NUM> and equipped inflator <NUM> are stowed inside the housing <NUM> of the airbag module <NUM> (see <FIG>).

<FIG> is a schematic diagram illustrating the behavior of the airbag module <NUM> of <FIG> during expansion and deployment. When the motorcycle <NUM> is traveling, the occupant P is in a forward leaning posture as illustrated in the position P'. In an emergency, as illustrated in <FIG>, the housing <NUM> is cleaved at the first weak portion <NUM> and the second weak portions 464a and 464b (see <FIG>). As a result, the airbag cushion <NUM> expands and deploys to the outside of the housing <NUM>, and as illustrated in <FIG>, the occupant P can therefore be restrained and protected.

Preferred examples of the present invention were described above while referring to the attached drawings. However, the embodiments described above are preferred examples of the present invention, and other embodiments can be implemented or performed by various methods. In particular, unless described otherwise in the specification of the present application, the invention is not limited to the shape, size, configurational disposition, and the like of parts illustrated in detail in the attached drawings.

Therefore, it is obvious that a person with ordinary skill in the art can conceive various changed examples or modified examples within the scope of the claims.

The present invention can be used as an airbag module provided with an airbag cushion and a case type housing for stowing the airbag cushion. Description of Codes.

Claim 1:
An airbag module (<NUM>), comprising:
a folded or rolled airbag cushion (<NUM>),
an inflator (<NUM>) equipped in said airbag cushion (<NUM>), and
a housing (<NUM> ; <NUM> ; <NUM> ; <NUM>) for stowing this airbag cushion (<NUM>), wherein
the housing (<NUM> ; <NUM> ; <NUM> ; <NUM>) has a convex polygonal shape in cross section, comprises at least a first pair of mutually opposed side surfaces and has an opening (<NUM> ; 210a ; 310a ; 410a) on the upper side, and when the airbag cushion (<NUM>) expands and deploys, the first pair of mutually opposed side surfaces is arranged to expand so as to separate from each other,
the airbag module (<NUM>) further comprises a cover (<NUM> ; <NUM>) covering the opening (<NUM> ; 210a ; 310a ; 410a) and side surfaces of the housing (<NUM> ; <NUM> ; <NUM> ; <NUM>),
the cover (<NUM> ; <NUM>) including an upper surface portion (440a) that covers the opening (<NUM> ; 210a ; 310a ; 410a) of the housing (<NUM> ; <NUM> ; <NUM> ; <NUM>) is formed with a first weak portion (<NUM>) that extends in the longitudinal direction of the upper surface portion (440a), that is weaker than the area surrounding thereof, and that is arranged to be cleaved by the separation of the first pair of side surfaces when the airbag cushion (<NUM>) expands and deploys,
the cover (<NUM> ; <NUM>) further includes a portion that covers a second pair of mutually opposed side surfaces of the housing (<NUM> ; <NUM> ; <NUM> ; <NUM>), formed with second weak portions (464a, 464b) that respectively extend continuously from a lower part of both ends of the first weak portion (<NUM>), that are weaker than a surrounding areas thereof, and that are arranged to cleave subsequent to cleaving of the first weak portion (<NUM>), and
the housing (<NUM> ; <NUM> ; <NUM> ; <NUM>) and the cover (<NUM> ; <NUM>) are each arranged to open rotationally with respect to the longitudinal axis to deploy the airbag cushion (<NUM>).