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. There are various types of airbag devices depending on the installation site and application. For example, in a driver's seat, a front airbag is provided in the center of a steering wheel. Furthermore, in a front passenger seat, a passenger airbag is provided on an instrument panel or a peripheral area thereof.

The shape of the airbag cushion of various airbag devices is devised in accordance with surrounding structures and the like so as to efficiently restrain an occupant. For example, an airbag <NUM> described in Patent Document <NUM> is for a front passenger seat, and is configured such that a forward expanding part <NUM> contacts and presses against an instrument panel I and a windshield W so as to stand on its own above the instrument panel I.

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

Document <NUM> discloses a front passenger seat airbag with two side panels, which are connected by three central panels. These panels are connected together sequentially, so that the three panels create a loop.

Cited Document <NUM> states that a foremost end portion B of a bottom portion 11a of the forward expanding part <NUM> may be arc-shaped (see paragraph <NUM>). However, depending on the degree of the arc shape of the foremost end portion B, it may affect the retention of the self-supporting posture of the airbag <NUM>. For example, if the radius of curvature of the arc shape of the foremost end portion B is large, a front surface portion 11b also protrudes greatly toward the windshield W, causing the front surface portion 11b to strongly interfere with the windshield W. In such a case, for example, the forward expanding part <NUM> may interfere with the windshield W and bounce up, the bottom portion 11a may rise off the instrument panel I, making it difficult for the airbag <NUM> to obtain a reaction force from the instrument panel I, or the front surface portion 11b may have a trough-like depression, making it difficult to absorb a load from the occupant.

In view of the foregoing, an objective of the present invention is to provide a front passenger seat airbag device capable of efficiently restraining an occupant while maintaining a self-supporting posture on an instrument panel and a method of manufacturing a front passenger seat airbag device.

In order to solve the problem above, a typical configuration of a front passenger seat airbag device according to the present invention includes:.

With the configuration above, the airbag cushion contacts the upper surface of the instrument panel through the strip-shaped main panel. In particular, in the front side expanding part of the airbag cushion formed by the acute angle portion of the side panel, the outer seam margin of the main panel is formed to extend further forward from the front end, such that the front end is less likely to become rounded. By efficiently forming the tapered front side expanding part in the airbag cushion in this manner, the airbag cushion can be suitably inserted between the instrument panel and the windshield in contact with the instrument panel, and thus the self-supporting posture of the airbag cushion can be maintained.

The airbag cushion may have a front side expanding part that includes the acute angle portions of the pair of side panels and expands so as to protrude to the front of the vehicle in a wedge shape along the upper surface of the instrument panel, and the outer seam margin may be in a condition extending from a front end of the front side expanding part. With the wedge-shaped front side expanding part, the front end is formed as an outer seam margin, and thus is less likely to become rounded, can suitably fit between the instrument panel and the windshield, and can contact the instrument panel with a flat surface, such that the self-supporting posture of the airbag cushion can be maintained.

The main panel may have a through hole formed at a location contacting the upper surface of the instrument panel and connected to the inflator in a condition in which a portion of the inflator is inserted. By connecting the through hole of the main panel to the inflator secured inside the instrument panel, the airbag cushion can be efficiently established on the upper surface of the instrument panel.

The airbag cushion further may have a diffuser provided in a periphery of the through hole of the main panel on the inner side of the airbag cushion to cover the inflator and guide gas in a prescribed direction. By providing the diffuser, it becomes possible to efficiently expand and deploy the airbag cushion.

Upper edges of the pair of side panels may extend in a shape that approximates a straight line. This configuration suppresses the airbag cushion from expanding in an excessively convex manner toward the windshield when expanded and deployed, and allows the front side expanding part of the airbag cushion to be smoothly inserted between the windshield and the instrument panel.

The upper edges of the pair of side panels may be curved downward and recessed. This configuration also suppresses the airbag cushion from expanding in an excessively convex manner toward the windshield when expanded and deployed, and allows the front side expanding part of the airbag cushion to be smoothly inserted between the windshield and the instrument panel.

The pair of side panels further may have: a front side region including the acute angle portion and positioned above the instrument panel; a restraining region positioned between the instrument panel and the occupant and extending below the front side region; and a recessed portion formed on a boundary between the front side region and the restraining region of the lower edges of the pair of side panels and curved upward and indented.

With the configuration above, when an occupant comes into contact with the airbag cushion, the airbag cushion bends at an angle corresponding to an approaching direction of the occupant starting from the recessed portion of the side panel, such that the occupant can be more appropriately restrained.

A typical configuration of a method of manufacturing a front passenger seat airbag device according to the present invention is a method of manufacturing a front passenger seat airbag device as defined by claim <NUM> the method including: a step of manufacturing a pair of side panels having an acute angle portion that extends along the upper surface of the instrument panel toward the front of the vehicle at an acute angle; a step of connecting edges of the pair of side panels together by a strip-shaped main panel to achieve a condition in which end portions on two sides of the main panel in a longitudinal direction further extend to the front of the vehicle to vertically overlap; a step of inverting the airbag cushion from an opening between the end portions of the main panel; and a step of joining the end portions of the main panel.

A front passenger seat airbag device having the functions and effects described above can be manufactured by the manufacturing method. In other words, the manufacturing method can manufacture a front passenger seat airbag device having an airbag cushion capable of efficiently restraining an occupant while favorably maintaining a self-supporting posture.

The present invention can provide: a front passenger seat airbag device capable of efficiently restraining an occupant while maintaining a self-supporting posture on an instrument panel; and a method of manufacturing a front passenger seat airbag device.

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.

<FIG> is diagrams illustrating the outlines of a front passenger seat airbag device <NUM> according to an embodiment of the present invention. <FIG> is a diagram illustrating a vehicle before activation of the front passenger seat airbag device <NUM>. Hereinafter, regarding <FIG> and other diagrams, a vehicle front-to-back direction is illustrated by the symbols F (Front) and B (Back), a vehicle width direction of the vehicle by the symbols L (Left) and R (Right), and a vehicle up-down direction by the symbols U (Up) and D (Down).

In the present Embodiment, the front passenger seat airbag device <NUM> is implemented as a passenger bag for a passenger seat (seat <NUM> on the right in the front row) in a vehicle with the steering wheel on the left side. Hereinafter, in order to provide descriptions assuming the seat <NUM> is on the right in the front row, for example, the outside of the vehicle in the width direction of the vehicle means the right side of the vehicle, while the inside of the vehicle in the width direction of the vehicle means the left side of the vehicle. Furthermore, "upward" refers to a head direction as viewed from an occupant <NUM> (see <FIG>) normally seated on the seat <NUM>, and "downward" refers to a lower limb direction as viewed from the occupant <NUM>.

An airbag cushion <NUM> (see <FIG>) of the front passenger seat airbag device <NUM> is stowed in a stowing part <NUM> provided in an instrument panel <NUM> of the vehicle. The stowing part <NUM> is installed in the front of the vehicle seat <NUM> and stows an inflator <NUM> (see <FIG>), which is a gas generating device, in addition to the airbag cushion <NUM>.

<FIG> is a diagram illustrating the vehicle after activation of the front passenger seat airbag device <NUM> in <FIG>. The airbag cushion <NUM> has a bag shape and is formed by overlaying and sewing or adhering a plurality of base fabrics forming a surface thereof.

<FIG> is a schematic cross-sectional view along A-A of the airbag cushion <NUM> of <FIG>. As illustrated in <FIG>, the airbag cushion <NUM> expands and deploys above the instrument panel <NUM> and between the instrument panel <NUM> and the occupant <NUM> of the seat <NUM> to restrain the occupant <NUM> from the front of the vehicle, while being in contact with the upper surface of the instrument panel <NUM>.

A part of the inflator <NUM>, which is a gas generating device, is inserted inside the airbag cushion <NUM>. The inflator <NUM> is secured to the inside of the instrument panel <NUM> using a stud bolt (not illustrated), and is actuated by an impact detection signal sent from a prescribed sensor to supply gas to the airbag cushion <NUM>. The airbag cushion <NUM> begins to expand by means of the gas from the inflator <NUM>, cleaves a cover <NUM> (see <FIG>), and expands and deploys toward the seat <NUM> based on the expansion pressure.

The inflator <NUM>, in the present Embodiment, is a disk type. Examples of currently prevailing inflators include: types which are filled with a gas generating agent and burn the agent to generate gas; types which are filled with compressed gas and supply gas without generating heat; hybrid types which utilize both combustion gas and compressed gas; and the like. Any of these types can be used for the inflator <NUM>.

The diffuser <NUM> is a member that rectifies gas from the inflator <NUM> and is provided inside the airbag cushion <NUM> so as to cover the inflator <NUM>. The diffuser <NUM> is provided with an opening for gas flow at a prescribed location. Providing the diffuser <NUM> enables expansion and deployment of the airbag cushion <NUM> to be performed in an efficient manner.

<FIG> is a diagram illustrating an outline of the airbag cushion <NUM> in <FIG>. <FIG> is a perspective view of the airbag cushion <NUM> when expanded and deployed in <FIG>. The airbag cushion <NUM> constitutes a central main panel <NUM> and a pair of left and right side panels <NUM>. The vehicle rear side of the airbag cushion <NUM> forms an occupant restraining part <NUM> having a large vertical dimension.

A front side expanding part <NUM> of the airbag cushion <NUM> on the front side of the vehicle expands along an upper surface 102a of the instrument panel <NUM> (see <FIG>) so as to protrude in a wedge shape to the front of the vehicle. The front side expanding part <NUM> enters a space between the instrument panel <NUM> and a windshield <NUM>, makes contact with the upper surface 102a of the instrument panel <NUM>, and maintains the airbag cushion <NUM> in a self-supporting posture.

<FIG> is a diagram illustrating the side panel <NUM> in <FIG>. A pair of the side panels <NUM> are provided on the airbag cushion <NUM> (see <FIG>), in a symmetrical shape in the vehicle width direction (left-right) and form side portions on two sides of the airbag cushion <NUM> in the vehicle width direction.

A front side region <NUM> of the side panels <NUM> is a region positioned above the instrument panel <NUM> (see <FIG>). The vehicle front side of the front side region <NUM> forms an acute angle portion <NUM> that forms a side portion of the wedge-shaped front side expanding part <NUM> in the vehicle width direction. The acute angle portion <NUM> extends along the upper surface 102a of the instrument panel <NUM> toward the front of the vehicle at an acute angle.

A restraining region <NUM> of the side panels <NUM> is a portion that forms the occupant restraining part <NUM> of the airbag cushion <NUM> (see <FIG>), is positioned between the instrument panel <NUM> and the occupant <NUM>, and is positioned below the front side region <NUM>. The restraining region <NUM> is provided with a vent hole <NUM> for discharging gas from an interior of the airbag cushion <NUM>.

An upper edge <NUM> of the side panel <NUM> that extends continuously from the front side region <NUM> and the restraining region <NUM> extends obliquely in a shape that approximates a straight line. The shape of the upper edge <NUM> of the side panel <NUM> that approximates a straight line prevents the airbag cushion <NUM> (see <FIG>) from expanding in an excessively convex manner toward the windshield <NUM> when expanded and deployed. This configuration enables the front side expanding part <NUM> to be smoothly inserted into the space between the windshield <NUM> and the instrument panel <NUM>.

A recessed portion <NUM> of a lower edge <NUM> of the side panel <NUM> is formed at a boundary between the front side region <NUM> and the restraining region <NUM>. The recessed portion <NUM> has a concave shape that curves upward. The recessed portion <NUM> is a portion positioned near a corner between the upper surface 102a and a design surface 102b of the instrument panel <NUM> (see <FIG>) when the airbag cushion <NUM> is expanded and deployed. By providing the recessed portion <NUM>, when the occupant <NUM> contacts the airbag cushion <NUM>, the occupant restraining part <NUM> of the airbag cushion <NUM> can bend at an angle corresponding to the approaching direction of the occupant <NUM> to absorb the load, thereby more appropriately restraining the occupant <NUM>.

<FIG> is a diagram illustrating the main panel <NUM> in <FIG>. The main panel <NUM> has an elongated strip shape, and the edges of the pair of side panels <NUM> (see <FIG>) are connected to each other by sewing or the like. The end portions 138a, 138b on two sides of the main panel <NUM> in the longitudinal direction gradually approach the front of the vehicle along the upper edge <NUM> and lower edge <NUM> of the side panels <NUM>, and then are joined by sewing or the like to each other at a position extending from a tip end of the acute angle portion <NUM> of the side panel <NUM> to form an outer seam margin <NUM> (see <FIG>).

The main panel <NUM> is provided with a through hole <NUM> connected to the inflator <NUM> (see <FIG>). The through hole <NUM> is formed at a location on the main panel <NUM> that contacts the upper surface 102a of the instrument panel <NUM>. A bolt hole <NUM> into which a stud bolt of the inflator <NUM> is inserted is also provided in the area of the through hole <NUM>. A part of the inflator <NUM> is inserted into the through hole <NUM> using the bolt hole <NUM> or the like and the through hole <NUM> is connected to the inflator <NUM>.

By securing the through hole <NUM> of the main panel <NUM> together with the inflator <NUM> (see <FIG>) to the inside of the instrument panel <NUM>, the airbag cushion <NUM> can be efficiently established on the upper surface 102a of the instrument panel <NUM>. Note that the diffuser <NUM> described above is also provided around the through hole <NUM> of the main panel <NUM> inside the airbag cushion <NUM> by sewing or the like.

<FIG> is enlarged views of the front side expanding part <NUM> of the airbag cushion <NUM> in <FIG>. <FIG> illustrates the front side expanding part <NUM> in <FIG> from the left side in the vehicle width direction. The outer seam margin <NUM> is formed at the front end of the front side expanding part <NUM>. The outer seam margin <NUM> is a portion where the end portions 138a, 138b (see <FIG>) of the main panel <NUM> are joined vertically by sewing or the like. In a conventional airbag cushion, the seam margin is formed on the inner side, but the front side expanding part <NUM> of the airbag cushion <NUM> is intentionally formed with the outer seam margin <NUM> positioned on the outer side, such that the front end of the front side expanding part <NUM> can be expanded and deployed at a more acute angle without becoming rounded.

<FIG> is a perspective view of the front side expanding part <NUM> of the airbag cushion <NUM> in <FIG> viewed obliquely from above. The outer seam margin <NUM> is formed by vertically overlapping and joining the end portions 138a, 138b on two sides of the main panel <NUM> in the longitudinal direction in a condition further extending to the front of the vehicle from the acute angle portion <NUM> of the pair of side panels <NUM>. In this manner, the outer seam margin <NUM> is formed at the front end of the front side expanding part <NUM> so as to extend in the vehicle width direction.

<FIG> is cross-sectional views of the front side expanding part <NUM> in <FIG>. <FIG> is a cross-sectional view along B-B of the front side expanding part <NUM> in <FIG>. By providing the outer seam margin <NUM>, the front side expanding part <NUM> is expanded and deployed in a wedge shape without becoming rounded. Therefore, a bottom surface <NUM> of the front side expanding part <NUM> is flatter and can make wide surface contact with the upper surface 102a of the instrument panel <NUM> (see <FIG>). This allows the airbag cushion <NUM> to efficiently stand on its own on the instrument panel <NUM>.

<FIG> is a cross-sectional view along C-C of the front side expanding part <NUM> in <FIG>. An inner seam margin <NUM> is formed at a location on the front side expanding part <NUM> other than the front end. The inner seam margin <NUM> joins an edge of the main panel <NUM> and the edges of the side panels <NUM> in a condition bent to the inner side of the airbag cushion <NUM>. The inner seam margin <NUM> is formed at all joints between the main panel <NUM> and the side panels <NUM>. In other words, the airbag cushion <NUM> has a seam margin formed on the inner side besides where the outer seam margin <NUM> is formed at the front end of the front side expanding part <NUM>, such that the seam margin does not come into contact with the occupant <NUM> (see <FIG>) or other structures.

As described above, in the front side expanding part <NUM> formed by the acute angle portion <NUM> of the side panels <NUM> and the end portion side of the main panel <NUM>, the outer seam margin <NUM> of the end portions 138a, 138b of the main panel <NUM> is formed to extend further forward from the front end, making the front end of the front side expanding part <NUM> difficult to become rounded. Therefore, the front side expanding part <NUM> is expanded and deployed in a tapered wedge shape. The front side expanding part <NUM> having this shape can form the flat bottom surface <NUM> (see <FIG>), make surface contact with the instrument panel <NUM>, and maintain a self-supporting posture of the airbag cushion <NUM>, while being suitably inserted between the instrument panel <NUM> (see <FIG>) and the windshield <NUM>. This allows the airbag cushion <NUM> to maintain a self-supporting posture and efficiently restrain the occupant <NUM>.

A method of manufacturing the front passenger seat airbag device <NUM> having the airbag cushion <NUM> described above will be described below.

The manufacturing method first includes a step of manufacturing the pair of side panels <NUM> (see <FIG>). The side panels <NUM> are manufactured to have the acute angle portion <NUM> that extends to the front of the vehicle at an acute angle along the upper surface 102a of the instrument panel <NUM> (see <FIG>).

In a subsequent step, edges of the pair of side panels <NUM> are joined together by the strip-shaped main panel <NUM> (see <FIG>). At this time, the end portions 138a, 138b on two sides of the main panel <NUM> in the longitudinal direction are processed so as to extend further to the front of the vehicle from the acute angle portion <NUM> of the pair of side panels <NUM> and to overlap vertically.

Next, a step of creating an opening between the end portions 138a, 138b of the main panel <NUM> and inverting the airbag cushion <NUM> from the opening is performed prior to forming the outer seam margin <NUM> (see <FIG>). With this step, a seam margin for connecting the side panels <NUM> and the main panel <NUM> is positioned inside the airbag cushion <NUM>, thereby forming the inner seam margin <NUM> (see <FIG>).

After the inner seam margin <NUM> (see <FIG>) is formed, a step of vertically joining the end portions 138a, 138b of the main panel <NUM> by sewing or the like is performed to form the outer seam margin <NUM> (see <FIG>). This completes the manufacture of the airbag cushion <NUM> having the wedge-shaped front side expanding part <NUM> and capable of maintaining a self-supporting posture.

The airbag cushion <NUM> manufactured by the manufacturing method described above is also useful for installation of the diffuser <NUM> (see <FIG>). Conventionally, an airbag cushion has been inverted using the through hole <NUM> for an inflator (see <FIG>) after sewing each panel member. However, in this method, when the diffuser <NUM> is provided around the through hole <NUM>, work must be performed in which the diffuser <NUM> must be sewn or the like inside the airbag cushion after the airbag cushion is inverted, thereby causing installation work of the diffuser <NUM> to be time consuming. On the other hand, with this manufacturing method, the airbag cushion <NUM> is inverted by opening the front end of the front side expanding part <NUM> instead of the through hole <NUM> for the inflator. Therefore, the diffuser <NUM> can be provided around the through hole <NUM> prior to the inversion process. In other words, with this manufacturing method, it is possible to easily install the diffuser <NUM> on the main panel <NUM> in advance.

Furthermore, with this manufacturing method, the diffuser <NUM> can also be installed on the main panel <NUM> in a folded and temporarily sewn state. The temporary sewing is sewing in which the thread breaks or frays when a certain amount of force is applied, thereby eliminating the thread. By folding the diffuser <NUM> and performing temporary sewing, it is possible to prevent the position of the diffuser <NUM> from shifting when the airbag cushion <NUM> is stowed. Furthermore, when gas pressure is applied, the temporary sewing is eliminated, the diffuser <NUM> is deployed, and a gas rectifying function of the diffuser <NUM> allows the airbag cushion <NUM> to smoothly expand and deploy. In providing such a temporarily sewn diffuser <NUM>, the aforementioned manufacturing method of opening the front end of the front side expanding part <NUM> and inverting the airbag cushion <NUM> is extremely useful.

Modified examples of each of the above-described components are described below. <FIG> is a modified example of the side panel <NUM> in <FIG> (side panel <NUM>). In <FIG>, the same signs are attached to the same structural elements as those described above, and a description of the aforementioned structural elements is omitted. In the following description, components having the same name as a component already described are assumed to have the same function unless otherwise specified, even if marked with a different sign.

In the side panel <NUM>, an upper edge <NUM> is curved downward and indented. The upper surface of the airbag cushion <NUM> (see <FIG>) bulges to some extent toward the windshield <NUM> in a rounded shape due to the pressure of the gas when receiving gas. Therefore, if the side panel <NUM> has the upper edge <NUM> curved and indented in advance, the airbag cushion <NUM> can be prevented from being excessively convex toward the windshield <NUM> by suppressing roundness when expanded and deployed. Therefore, even if the side panel <NUM> is used, the wedge-shaped front side expanding part <NUM> can be efficiently formed, and thus the front side expanding part <NUM> can be smoothly inserted into the space between the windshield <NUM> and the instrument panel <NUM>.

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. Furthermore, expressions and terms used in the specification of the present application are used for providing a description, and the invention is not limited thereto, unless specifically described otherwise.

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 in a front passenger seat airbag device having an airbag cushion that expands and deploys between an instrument panel of a vehicle and an occupant on a front passenger seat, and in a method of manufacturing a front passenger seat airbag device.

Claim 1:
A front passenger seat airbag device (<NUM>), comprising:
an airbag cushion (<NUM>) that expands and deploys above an instrument panel (<NUM>) of a vehicle and between the instrument panel (<NUM>) and a front passenger seat (<NUM>) in a condition contacting an upper surface of the instrument panel (<NUM>); and
an inflator (<NUM>) that supplies gas to the airbag cushion (<NUM>), the inflator (<NUM>) being secured to an inner side of the instrument panel (<NUM>); wherein
the airbag cushion (<NUM>) includes:
a pair of side panels (<NUM>) that form side portions on two sides of the airbag cushion (<NUM>) in a vehicle width direction, and
a strip-shaped main panel (<NUM>) connecting edges of the pair of side panels (<NUM>) to each other;
the pair of side panels (<NUM>) have an acute angle portion (<NUM>) that extends along the upper surface (102a) of the instrument panel (<NUM>) toward the front of the vehicle at an acute angle; and
the airbag cushion (<NUM>) further includes:
an inner seam margin (<NUM>) in which an edge of the main panel (<NUM>) and edges of the pair of side panels (<NUM>) are joined in a condition bent to the inner side of the airbag cushion (<NUM>), and
an outer seam margin (<NUM>) in which end portions (138a, 138b) on two sides of the main panel (<NUM>) in a longitudinal direction are vertically overlapped and joined in a state further extending to the front of the vehicle from the acute angle portion (<NUM>) of the pair of side panels (<NUM>).