Patent Description:
Currently, nearly all vehicle steering wheels are equipped with a driver's seat airbag device. The airbag cushion of the driver's seat airbag device is primarily stored 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.

Normally, the shape of an airbag cushion is determined based on the assumption that the occupant is seated in the seat in a normal posture. However, the occupant may not always be in a normal seating position, for example, when the occupant unexpectedly leans forward. When the occupant is in a non-normal seating position relative to the seat (commonly known as out-of-position), the airbag cushion may contact the head of the occupant from below in the unlikely event of an emergency situation. In this case, the airbag cushion will cause the head of the occupant to retroflex backwards. Due to the structure of the human body, it is known that movements that rotate the head, such as retroflexing backwards, tend to place a burden on the body.

As a countermeasure for the above out-of-position, for example, in Patent Document <NUM>, a rearwardly tilting flap <NUM> is provided in an airbag <NUM>. The rearwardly tilting flap <NUM> is described as having the function of suppressing the rearwardly tilting moment of the head when the airbag <NUM> starts to expand and deploy in close proximity to the head of the occupant that is out-of-position (paragraph <NUM>).

[Patent Document <NUM>] <CIT> Documents <CIT>, <CIT> and <CIT> each disclose air bags having cloth members located on a lower side of the airbag and guiding said airbag upwards.

However, as described in <FIG> of Patent Document <NUM>, the rearwardly tilting flap <NUM> is a long strip of material, one side of which is a free end. Therefore, the rearwardly tilting flap <NUM> may shift from the initially set position due to vibration or the like while stowed, or due to momentum when the airbag <NUM> is expanded and deployed. In order to increase the safety of the airbag <NUM> by means of the rearward tilting flap <NUM>, the rearward tilting flap <NUM> must be properly deployed in the desired position.

In view of these issues, an object of the present invention is to provide a driver's seat airbag device capable of fully restraining an occupant while giving consideration to safety aspects during expansion and deployment.

To solve the problems as described above, a driver's seat airbag device according to the present invention is defined by claim <NUM>.

According to the configuration described by claim <NUM>, when the head of the occupant is forward, the upper portion of the airbag cushion is covered with a cloth member, so that the occupant contacts the airbag cushion via the cloth member. The cloth member is then sandwiched between the occupant and the airbag cushion, making it difficult for the cloth member to move, which resists the expanding airbag cushion. This suppresses the behavior of the airbag cushion attempting to move toward the head of the occupant, or suppresses the load when the airbag cushion contacts the head, thereby preventing the head from being pushed up and retroflexed backward.

In particular, since the cloth member described above is stowed in a state pressed by the cover member from above, displacement can be prevented when subjected to vibration or the like, and when the cover door of the cover member is opened, the airbag cushion can start expanding and deploying leading with the cloth member. Accordingly, the configuration described above prevents misalignment of the cloth member both while stowed and during expansion and deployment of the airbag cushion, and enables the cloth member to be efficiently deployed to the desired position.

The cover member described above may have a design region that covers the airbag module and a wall part extending from the design region to enclose the airbag module, and one or a plurality of cover doors may be formed in the design region. With this configuration, a cover door that opens based on the expansion pressure of the airbag cushion can be suitably achieved.

The airbag module described above may be installed on the module installation surface with the rear end side of the cloth member reaching the bottom side of the airbag cushion in stowed form and folded between the airbag cushion and the wall part of the cover member. This configuration prevents misalignment of the cloth member while stowed and enables the cloth member to be efficiently deployed in the desired position.

The airbag module described above may be installed on the module installation surface with the rear end side of the cloth member reaching the bottom side of the airbag cushion in stowed form and wound or folded together with the airbag cushion. This configuration also prevents misalignment of the cloth member while stowed and enables the cloth member to be efficiently deployed in a desired position.

The airbag module described above may be installed on the module installation surface with a midway location of the cloth member folded between the airbag cushion and the design region of the cover member. According to this configuration, the dimensions of the cloth member while stowed can be suppressed while preventing the cloth member from being displaced while stowed.

The airbag module described above may have a temporary fastening part that temporarily fastens the folded portion of the cloth member, and the temporary fastening part may be release-able by expansion pressure of the airbag cushion. With this configuration, the cloth member can be reduced in size and prevented from being misaligned while stowed, while the cloth member can be smoothly deployed during expansion and deployment of the airbag cushion by releasing the temporary fastening part.

The temporary fastening part described above may be sewn in such a way as to enable being ruptured by the expansion pressure of the airbag cushion. According to this configuration, the temporary fastening part can be suitably released in accordance with the expansion and deployment of the airbag cushion.

To solve the problems as described above, a configuration of the driver's seat airbag device according to the present invention is a driver's seat airbag device as defined by claim <NUM>.

According to this configuration, when the head of the occupant is forward, the upper portion of the airbag cushion is covered with a cloth member so that the occupant contacts the airbag cushion via the cloth member. The cloth member is then sandwiched between the occupant and the airbag cushion, making it difficult for the cloth member to move, which resists the expanding airbag cushion. This suppresses the behavior of the airbag cushion attempting to move toward the head of the occupant, or suppresses the load when the airbag cushion contacts the head, thereby preventing the head from being pushed up and retroflexed backward.

In particular, since the cloth member described above is stowed in a state pressed by the cover member from above, displacement can be prevented when subjected to vibration or the like, and when the cover door of the cover member is opened, the airbag cushion can start expanding and deploying leading with the cloth member. Furthermore, the cloth member is configured to deploy when the airbag cushion expands and deploys based on releasing of the engaging part or breaking the fragile part, thus efficiently preventing misalignment while stowed.

The prescribed location of the steering wheel described above may include the wall part of the cover member. This configuration also allows a cloth member to be applied to the upper portion of the expanding and deploying airbag cushion.

The prescribed location on the steering wheel as described above can include the module installation surface. This configuration also allows a cloth member to be applied to the upper portion of the expanding and deploying airbag cushion.

The prescribed location of the steering wheel described above may include a location between the cover member and the portion adjacent to the cover member, and the front end side of the cloth member may be sandwiched between the above portions. This configuration also allows a cloth member to be applied to the upper portion of the expanding and deploying airbag cushion.

The one or plurality of cover doors described above may open upwardly, and the prescribed location of the steering wheel may include an area of the design region that is at or above the cover doors. This configuration also allows a cloth member to be applied to the upper portion of the expanding and deploying airbag cushion.

The one or plurality of cover doors described above may open upwardly. A cover door that opens upward provides a downward reaction force to the airbag cushion, thereby suppressing the deployment behavior of the airbag cushion that attempts to move toward the head of the occupant.

The airbag cushion has a restraining surface capable of restraining the chest of the occupant, and the cloth member is applied over the restraining surface from the top of the expanding and deploying airbag cushion. When the airbag cushion is expanded and deployed, the cloth member is sandwiched between the chest of the occupant and the airbag cushion, making it difficult for the cloth member to move. This allows the cloth member to resist the airbag cushion attempting to expand, and to suppress the behavior of the airbag cushion attempting to move toward the head of the occupant.

The upper portion of the expanded and deployed airbag cushion described above may be thicker in the vehicle front-rear direction than the lower portion of the airbag cushion. With this configuration, the upper portion of the airbag cushion can restrain the head of the occupant with the thickness thereof, and the lower portion can easily enter the narrow space between the steering wheel and the abdomen of the occupant. In particular, the lower portion of the airbag cushion is sandwiched between the steering wheel and the abdomen. Therefore, the shape of the airbag cushion is less likely to collapse, and the head restraining performance by the upper portion can also be improved.

A portion of the inflator described above may be inserted into the airbag cushion, a portion of the inflator may have a prescribed gas discharge port, the airbag cushion may have a rectifying cloth covering a portion of the inserted inflator, and the rectifying cloth may have an opening below a portion of the inflator.

The flow-regulating material described above allows gas supplied from the inflator to flow downward through the opening part, and thus the airbag cushion can expand from a lower portion side. Thus, the airbag cushion can quickly enter the space between the steering wheel and the abdomen of the occupant.

The airbag cushion in stowed form as described above may have a portion, which is centered on the occupant side when expanded and deployed, contact the cover member over the cloth member. According to this configuration, the airbag cushion can be efficiently expanded and deployed leading with the cloth member and the portion that is centered on the occupant side as the leading portion.

The airbag cushion in stowed form described above may be wound or folded radially from the periphery to the apex and contracted, with the apex being the center portion on the occupant side. According to this configuration, the portion of the airbag cushion that is centered on the occupant side can be efficiently positioned on the cover member side.

The steering wheel described above has a hub including a module installation surface and a cover member, and a rim to be grasped by an occupant, wherein the rim may have a shape in which an upper extent of the hub is partially omitted or in which a part located above the hub is closer to the hub side than a part located on either side of the hub.

Many new steering wheels that have been developed in recent years are not in conventional circular shape, and various designs exist, such as rims that exist only on the left and right sides of the hub, or rims in which the upper part of the hub is shaped closer to the hub side. These non-circular shaped steering wheels (variant steering wheels) do not have a part of the rim that is above the hub, or the dimensions of the upper part of the rim are omitted, and the like, enabling heads of occupants to travel further forward than with conventional steering wheels. Thus, in the unlikely event of an emergency situation when the occupant is in a non-normal seating position relative to the seat (commonly known as out-of-position), such as when the head of the occupant is forward, the airbag cushion may expand and deploy from below relative to the head of the occupant. In such a case, a conventional airbag cushion may push the head of the occupant up and cause the head to retroflex backward, which may cause physical strain. Therefore, installing an airbag module equipped with the cloth member described above in the variant steering wheel enables suitably utilizing the effect of the cloth member in reducing the burden on the occupant.

The cloth member described above may have a coefficient of static friction of the surface on the occupant side that is greater than the coefficient of static friction of the surface on the airbag cushion side. According to this configuration, the static frictional force between the cloth member and the occupant is increased, thus preventing the cloth member from slipping off the occupant and enabling the airbag cushion to fully restrain the occupant while allowing the cloth member to function suitably.

The cloth member described above may be coated with a prescribed resin on the occupant side surface. This configuration enables increasing the static frictional force between the cloth member and the occupant.

According to the present invention, a driver's seat airbag device capable of fully restraining an occupant while giving consideration to safety aspects during expansion and deployment can be provided.

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 a diagram illustrating an overview of a driver's seat airbag device <NUM> according to an embodiment of the present invention. <FIG> is a diagram illustrating a vehicle before activation of the driver's seat airbag device <NUM>. Hereinafter, regarding <FIG> and other diagrams, a vehicle front-rear 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).

The driver's seat airbag device <NUM> is applied in the present embodiment as the driver airbag for the driver's seat for vehicles with a steering wheel on a left side (front row left side seat <NUM>). Hereinafter, explanations are made assuming the front row left side seat <NUM>, for example, a vehicle outer side in the vehicle width direction (hereinafter, outer vehicle side) refers to a left side of the vehicle, and a vehicle inner side in the vehicle width direction (hereinafter, vehicle inner side) refers to a right side of the vehicle.

The airbag cushion (hereinafter referred to as the cushion <NUM> (see <FIG>) of the driver's seat airbag device <NUM> is stowed, folded, wound, or the like, in front of the seating position of the seat <NUM>, inside a central hub <NUM> of the steering wheel (variant steering wheel <NUM> described below). At this time, the cushion <NUM> is stowed together with an inflator <NUM> (see <FIG>) that supplies the gas, forming an airbag module <NUM> (see <FIG>). The hub <NUM> includes a surface cover member <NUM> and a module installation surface <NUM> (see <FIG>) and the like.

The variant steering wheel <NUM> on which the cushion <NUM> is installed in the present embodiment is assumed to be of a configuration in which an operation of the occupant is converted into an electrical signal and transmitted to the wheel. The variant steering wheel <NUM> has a rim <NUM> of a shape other than a circular ring, and is different in shape from a conventional steering wheel with a circular rim. The rim <NUM> is a part to be grasped by the occupant, and accepts operations causing rotation around the central hub <NUM>, but unlike conventional circular rims, operations to rotate the rim at a large angle are not necessary, so there is no need to pass the rim between the left and right hands. As a result, the rim <NUM> is shaped to be present only on the left, right and lower sides the hub <NUM>, and the area above the hub <NUM> being partially omitted.

The variant steering wheel <NUM> is an example of one having a shape in which a portion of the upper area of the hub <NUM> is omitted. Other examples of variant steering wheels <NUM> can include a shape in which the portion located above the hub is closer to the hub side than the portion located to the left or right of the hub, or a rim (grip) that is present only on the left or right side of the hub.

The upper side of the hub <NUM> means the side above the straight line connecting <NUM> o'clock and <NUM> o'clock in the case where the variant steering wheel <NUM> is regarded as a clock and the axis of the hands of the clock is located at the center of the hub <NUM>. The upper portion of the variant steering wheel <NUM> may be installed tilted toward the front of the vehicle. As a result, the vertical direction of the variant steering wheel <NUM> is the direction connecting <NUM> o'clock and <NUM> o'clock when the variant steering wheel <NUM> is viewed as a clock, which may not match the actual vertical direction. The left and right directions of the variant steering wheel <NUM> are the <NUM> o'clock or <NUM> o'clock directions when the variant steering wheel <NUM> is viewed as a clock.

<FIG> is a diagram illustrating a vehicle after the cushion <NUM> of the driver's seat airbag device <NUM> expands and deploys. The cushion <NUM> begins to expand while a cover <NUM> (see <FIG>) is forced open by gas from an inflator <NUM> (see <FIG>), and expands and deploys into a bag shape in front of the seating position of the seat <NUM> to restrain the upper body and head of the occupant from moving forward. The cushion <NUM> has a circular shape as viewed from the seating position side, and is formed by overlaying a plurality of panels that form the surface thereof and then stitching or adhering. The cushion <NUM> is covered with a cloth member <NUM> as a member unique to the driver's seat airbag device <NUM>. The cloth member <NUM> has the function of preventing the head of the occupant from retroflexing backward (see <FIG>).

<FIG> is a diagram illustrating a cushion <NUM> in <FIG> from each direction during expansion and deployment. <FIG> illustrates the cushion <NUM> in <FIG> seen from slightly above the vehicle outer side. In <FIG>, a portion of the panel configuring the cushion <NUM> is cut out to expose the internal inflator <NUM>.

The cushion <NUM> in the present embodiment has a shape similar to a truncated cone, with the diameter widening from the variant steering wheel <NUM> side (see <FIG>) toward the occupant side (vehicle rear side).

The cloth member <NUM> is in the form of a band in the present embodiment, and is passed over the upper portion of the expanded and deployed cushion <NUM> in the vehicle front-rear direction. The cloth member <NUM> has a front end side 150a (see <FIG>) connected to stud bolts <NUM> of the inflator <NUM>, and a rear end side 150b is a free end. The cloth member <NUM> can be formed from a base fabric of the same material as the cushion <NUM>, but can also be formed from other fabric-like materials.

The inflator <NUM> is a device for supplying gas, and in the present embodiment, a disk type is used. The inflator <NUM>, where a portion thereof formed with a gas discharge port <NUM> is inserted into the cushion <NUM> through a rear panel <NUM>, is activated based on an impact detection signal transmitted from a sensor (not shown) to supply gas to the cushion <NUM>. The inflator <NUM> is provided with a plurality of stud bolts <NUM>. The stud bolts <NUM> pass through the rear panel <NUM> of the cushion <NUM> and is fastened to the module installation surface <NUM> (see <FIG>) of the variant steering wheel <NUM>. The cushion <NUM> is also secured to the interior of the hub <NUM> by the fastening the stud bolts <NUM>.

Note that examples of currently prevailing inflators include: types filled with a gas generating agent and that burns the agent to generate a gas; types filled with a compressed gas and supplies the gas without generating heat; hybrid types that utilize both a combustion gas and a compressed gas; and the like. Any of these types of inflators can be used as the inflator <NUM>.

<FIG> is a diagram illustrating the cushion <NUM> of <FIG> from a left side in the vehicle width direction. The cushion <NUM> is formed from a plurality of panels and includes a front panel <NUM> located on the occupant side, a rear panel <NUM> located on the variant steering wheel <NUM> side (see <FIG>), and side panels <NUM> connecting the front panel <NUM> and the rear panel <NUM> to form the side portions of the cushion <NUM>.

The expanded and deployed cushion <NUM> is shaped along a truncated cone, but is generally slightly inclined. Specifically, the shape is inclined such that a center P1 of the front panel <NUM> in a height direction is positioned above an imaginary line L1 horizontally extended from a center P2 of the rear panel <NUM> in the height direction. When the cushion <NUM> is expanded and deployed, the front panel <NUM> is arranged to extend substantially vertically, while the rear panel <NUM> is arranged so that the upper portion thereof is inclined to collapse to the vehicle front side (left side in <FIG>). As a result, in the vehicle front-rear direction, the width W1 of an upper portion 104a of the expanded and deployed cushion <NUM> is thicker than the width W2 of a lower portion 104b of the cushion <NUM>.

<FIG> is a diagram illustrating the cushion <NUM> of <FIG> from above. The cushion <NUM> is in the shape of an essentially symmetrical truncated cone when viewed from above. The cloth member <NUM> is configured to be passed over the upper end surface of the cushion <NUM> in the center of the vehicle width direction in the vehicle front-rear direction.

<FIG> is a diagram illustrating each panel configuring the cushion <NUM> in <FIG>. In <FIG>, each panel is illustrated in a state spread out on a plane. <FIG> is a diagram illustrating the front panel <NUM> of <FIG>. The front panel <NUM> is circular and expands in front of the upper body of an occupant seated in the driver's seat when the cushion <NUM> is expanded and deployed, forming an occupant restraining surface to restrain the occupant.

<FIG> is a diagram illustrating the rear panel <NUM> in <FIG>. The rear panel <NUM> is circular and forms a reaction surface that captures reaction forces from the variant steering wheel <NUM> (see <FIG>) when the cushion <NUM> is expanded and deployed. A securing area <NUM> is formed in the center of the rear panel <NUM> where the inflator <NUM> (see <FIG>) is inserted and secured to the module installation surface <NUM> (see <FIG>). The cushion <NUM> expands and develops in a shape of a truncated cone spreading toward the occupant side, and therefore, the rear panel <NUM> has a narrower area than the front panel <NUM> (see <FIG>).

<FIG> is a diagram illustrating the side panel <NUM> of <FIG>. The side panel <NUM> has an arcuate strip shape in a state spread out on a plane. Of two arcs <NUM> and <NUM>, the arc <NUM> on the larger diameter side is joined by sewing to the edge of the front panel <NUM> (see <FIG>), and the arc <NUM> on the smaller diameter side is joined by sewing to the edge of the rear panel <NUM> (see <FIG>). Longitudinal ends 134a and 134b of the side panels <NUM> are joined together at the bottom or top of the cushion <NUM>. The side panels <NUM> are also provided with vent holes 126a and 126b for emitting gas to the outside.

The two arcs <NUM> and <NUM> of the side panels <NUM> are joined to the entire circumference of the edge of the front panel <NUM> and the entire circumference of the edge of the rear panel <NUM>, respectively. As a result, the cushion <NUM> of <FIG> is configured with the side panels <NUM> intervening throughout between the front panel <NUM> and the rear panel <NUM>. In other words, the cushion <NUM> is manufactured in the shape of a three-dimensional bag, with the occupant side surface, the vehicle front side surface, and the side surface formed respectively by a total of three panels, while maintaining ease of sewing and the like.

<FIG> is a diagram illustrating the cloth member <NUM> in <FIG>. The cloth member <NUM> is in the form of a strip and is set to be long enough to reach from the rear panel <NUM> (see <FIG>), across the side panels <NUM>, and near the center of the front panel <NUM>. Holes 152a, 152b are provided in the front end side 150a of the cloth member <NUM> for fastening to the stud bolts <NUM> of the inflator <NUM>.

<FIG> is a diagram illustrating the airbag module <NUM> in <FIG> in stowed form. <FIG> is a perspective view of the airbag module <NUM> in stowed form. The stowed form is the form when the airbag module is stowed in the variant steering wheel <NUM> (see <FIG>). The airbag module <NUM> is installed on the variant steering wheel <NUM> in the form of a cushion <NUM> that is wound, folded or otherwise bundled in a smaller form.

The cloth member <NUM> is passed from the upper portion of the cushion <NUM> in stowed form across the cover member <NUM> side (see <FIG>) to reach the lower part of the cushion <NUM>. The excess portion of the rear end side 150b is folded at the bottom of the cushion <NUM>.

<FIG> is a cross-sectional view taken along line A-A of the hub <NUM> of the variant steering wheel <NUM> in <FIG>. <FIG> schematically illustrates how the airbag module <NUM> in the stowed form of <FIG> looks when stowed in the hub <NUM> of the variant steering wheel <NUM> in <FIG>.

The airbag module <NUM> is installed on the module installation surface <NUM> inside the hub <NUM> of the variant steering wheel <NUM> using the stud bolts <NUM> of the inflator <NUM> (see <FIG>). The cover member <NUM> of the hub <NUM> is mounted at a prescribed location of the variant steering wheel <NUM> so as to cover the airbag module <NUM> installed on the module installation surface <NUM> from the rear side of the vehicle (in other words, the occupant side).

The cover member <NUM> has a design region <NUM> where emblems and other decorations are applied to the front side. The design region <NUM> covers the airbag module <NUM> on the occupant side. The cover member <NUM> has a wall part <NUM> that covers a side surface of the airbag module <NUM>. The wall part <NUM> is formed on the back side of the design region <NUM> to enclose the airbag module <NUM>.

The design region <NUM> of the cover member <NUM> has a cover door <NUM> (see <FIG>) that opens by expansion pressure of the cushion <NUM>. The cover member <NUM> is configured to use the cover door <NUM> to release the cushion <NUM> when the cushion <NUM> is expanded and deployed.

The airbag module <NUM> is installed on the module installation surface <NUM> with a cover member <NUM> over the cloth member <NUM>, and with the cloth member <NUM> sandwiched between the cover member <NUM> and the cushion <NUM> in stowed form. At this time, the rear end side 150b of the cloth member <NUM> has reached the lower side of the cushion <NUM> and is folded between the cushion <NUM> and the wall part <NUM> of the cover member <NUM>. According to these configurations, even if the cloth member <NUM> is subjected to vibrations or the like while stowed, the cloth member <NUM> can be prevented from shifting in position, and the cloth member <NUM> can be efficiently deployed to the desired position during expansion and deployment of the cushion <NUM>.

The cushion <NUM> in stowed form is configured such that the center portion thereof on the occupant side when expanded and deployed contacts the design region <NUM> of the cover member <NUM> over the cloth member <NUM>. For example, an apex <NUM> of the cover member <NUM> side of the cushion <NUM> in stowed form in <FIG> is formed by a portion corresponding to a center P1 in the height direction of the front panel <NUM> in <FIG> and the center of the circular front panel <NUM> in <FIG>. By using the center of the front panel <NUM> as the apex <NUM> and having this apex <NUM> contact and accommodate the design region, the cushion <NUM> can be efficiently expanded and deployed leading with the center of the front panel <NUM>.

As described with reference to <FIG>, the cushion <NUM> is formed into a three-dimensional bag by three panels. The cushion <NUM> in stowed form of <FIG> can be formed, for example, by making the center of the front panel <NUM> of <FIG> the apex <NUM>, and wrapping or folding the surrounding side panels <NUM> and the like radially toward this apex <NUM> and contracting them. This enables efficiently placing the portion of the cushion <NUM> that is centered on the occupant side of the cushion <NUM> on the cover member <NUM> side.

<FIG> is a diagram illustrating the cushion <NUM> of <FIG> and the occupant <NUM> in a normal seating position. <FIG> illustrates an occupant <NUM> normally seated in the cushion <NUM> and seat <NUM> as viewed from the left side in the vehicle width direction. The cushion <NUM> can restrain the occupant <NUM> from the head <NUM> to the chest <NUM>, and to the abdomen <NUM> thereof, with the occupant side front panel <NUM> as the primary restraining surface.

In the present example, as described with reference to <FIG>, the upper portion 104a of the expanded and deployed cushion <NUM> is configured to be thicker in the vehicle front-rear direction than the lower portion 104b of the cushion <NUM>. In particular, the expanded and deployed cushion <NUM> is installed in an orientation whereas a boundary L2 between the side panel <NUM> and the front panel <NUM> extends upwardly when viewed from the vehicle width direction. In an emergency, the occupant <NUM> attempting to move forward in the vehicle will make contact at an early stage from the upper portion 104a of the cushion <NUM>. The upper portion 104a of the cushion <NUM> absorbs a load from the head <NUM> of the occupant <NUM> with a thickness thereof.

As described with reference to <FIG>, the width W2 in the vehicle front-rear direction of the lower portion 104b of the cushion <NUM> is slightly smaller than the width W1 of the upper portion 104a. In an ordinary vehicle, the steering wheel is inclined at an angle of approximately <NUM>° to <NUM>° to the vehicle front side, and a space between the steering wheel and the occupant <NUM> narrows in the vehicle front-rear direction toward the side of the lower abdomen <NUM>. With the cushion <NUM> of the present example, the width in the vehicle front-rear direction decreases as the cushion moves toward the lower portion 104b, and therefore, the lower portion 104b easily enters the narrow space between the variant steering wheel <NUM> and the abdomen <NUM>.

According to the configuration described above, the lower portion 104b of the cushion <NUM> is sandwiched by the variant steering wheel <NUM> and the abdomen <NUM>, and thus the shape of the cushion <NUM> is less likely to collapse. Furthermore, the restraining performance of the upper portion 104a of the cushion <NUM> with regard to the head <NUM> of the occupant <NUM> is also improved as a result. In particular, by stabilizing the orientation of the cushion <NUM>, movement of the head <NUM> of the occupant <NUM>, such as forward bending and backward retroflexing of the head <NUM>, which can easily cause physical strain, can be prevented.

As described above, the cushion <NUM> of the present embodiment is configured with a wide area of the front panel <NUM>, which serves as the occupant restraining surface, and a narrow area of the rear panel <NUM>, which captures a reaction force from the variant steering wheel <NUM>. The variant steering wheel <NUM> has a narrower contact range with the airbag cushion than a conventional circular steering wheel. The rear panel <NUM> can be set to a dimension according to the variant steering wheel <NUM> so as to omit portions that do not contact the variant steering wheel <NUM>. This enables reducing the amount of material used to construct the rear panel <NUM> and to reduce the gas capacity of the cushion <NUM>, thereby contributing to cost reduction.

The cushion <NUM> of the present embodiment can be set to have a gas capacity in the range of <NUM> to <NUM> liters by employing a small diameter rear panel <NUM>. This reduces the number of panels configuring the cushion <NUM>. Therefore, the cushion <NUM> can be folded or the like into a smaller storing form, and thus can be easily installed on the variant steering wheel <NUM> with limited storing space.

A gas capacity within the aforementioned range eliminates the need for a high output inflator and an inflator <NUM> (see <FIG>), which is as small and inexpensive as possible, can be used. For example, the inflator <NUM> can use an output in a range of <NUM> kPa to <NUM> kPa. An inflator <NUM> of this output is small and inexpensive, which is beneficial in terms of weight reduction and cost reduction. Reducing the gas capacity of the cushion <NUM> shortens the time required for the expansion of the cushion <NUM> to be completed, which leads to the improvement of the occupant restraining performance.

In the present embodiment, an upper end 120a of the front panel <NUM> of the expanded and deployed cushion <NUM> is set to be located at a height within a range of ±<NUM> of the center of gravity of the head of an adult male. For example, the occupant <NUM> in <FIG> is assumed to be a test dummy doll AM50 (50th percentile male equivalent, <NUM> tall and <NUM> in weight) that mimics a physique that conforms to 50th percentile, or the average U. adult male. The upper end 120a of the front panel <NUM> of the cushion <NUM> is set to be located at a height within a range of ±<NUM> of a center of gravity P3 of the head of this AM50.

The head <NUM> of the occupant <NUM>, when in contact with the front panel <NUM> from the chin, forehead, or the like, may cause a rotational movement such as forward retroflexing or backward retroflexing. As described above, forward retroflexing and backward retroflexing of the head <NUM> are likely to cause a burden on the body due to the structure of the human body. The cushion <NUM> of the present embodiment contacts the front panel <NUM> from the center of gravity P3 of the head, restraining the head <NUM> and preventing excessive movement and reducing the burden on the body.

<FIG> is a diagram illustrating the cushion <NUM> in <FIG> and the occupant <NUM> in a non-normal seating position. <FIG> illustrates the occupant <NUM> in a non-normal seating position (commonly referred to as out-of-position) relative to the cushion <NUM> and seat <NUM> (see <FIG>), viewed from the left in the vehicle width direction.

The cushion <NUM> approaches the head of the occupant from below, for example, when the occupant is leaning out of the seat <NUM> (see <FIG>). However, in the airbag module <NUM> of the present embodiment, the occupant <NUM> is in direct contact with the cloth member <NUM> as the cloth member <NUM> is passed from the upper portion of the cushion <NUM> to the front panel <NUM>, which is the restraining surface. At this time, the front end side 150a of the cloth member <NUM> is secured to the stud bolts <NUM> of the inflator <NUM> (<FIG>), while the rear end side 150b of the cloth member <NUM> is sandwiched between the chest <NUM> or the like of the occupant <NUM> and the cushion <NUM>, making it difficult for the cloth member to move. As a result, the cloth member <NUM> resists the cushion <NUM> moving to expand and deploy from below, with the front end side 150a and the rear end side 150b in a secured state.

<FIG> is a diagram of the airbag module <NUM> and the occupant <NUM> in <FIG> as viewed from the front of the vehicle. As described above, the cloth member <NUM> is sandwiched between the occupant <NUM> and the cushion <NUM>, making it difficult for the cloth member to move and causing the cloth member to press downwardly on the cushion <NUM>. This causes the cushion <NUM> to expand in such a way as to avoid the cloth member <NUM> to the left and right, for example.

According to the configuration described above, the deployment behavior of the cushion <NUM> toward the head <NUM> of the occupant <NUM> can be suppressed, or the load when the cushion <NUM> contacts the head <NUM> can be suppressed, preventing the head <NUM> from being pushed up and retroflexed backward.

In particular, as described with reference to <FIG>, the cloth member <NUM> is stowed in a state being pressed by the cover member <NUM> from above, and when the cover door <NUM> (see <FIG>) of the cover member <NUM> is opened, the cushion <NUM> begins to expand and deploy leading with the cloth member <NUM>. Accordingly, the present embodiment prevents misalignment of the cloth member <NUM> both while stowed and during expansion and deployment of the cushion <NUM>, and enables efficient deployment of the cloth member <NUM> at a desired position, or in other words, between the cushion <NUM> in the process of deployment and the head <NUM> to the chest <NUM> of the occupant <NUM>.

The cloth member <NUM> functions primarily when the cushion <NUM> starts to expand and deploy in proximity to the occupant <NUM> (see <FIG>) in a non-normal seating position, in other words, in the middle of the expansion and deployment of the cushion <NUM>. For example, if the occupant <NUM> is present in a normal seating position (<FIG>) and there is distance between the cushion <NUM> and the occupant <NUM>, the cushion <NUM> will have completed expansion and deployment and will be greatly inflated. In that state, the cloth member <NUM> may not be draped over the front panel <NUM>.

The cloth member <NUM> can be treated to increase frictional resistance in order to make it easier to sandwich the cloth member between the occupant <NUM> and the cushion <NUM>. For example, the frictional resistance of the cloth member <NUM> can be increased by applying a silicone coating to the surface of the occupant <NUM> side of the cloth member <NUM>. Although the cloth member <NUM> is in the form of a band in the present embodiment, the area thereof can be increased or the width can be narrowed to make the cloth member a cord. These wide area cloth members and thread-like cloth members can also be used to hold the cushion <NUM> downward by being sandwiched between the cushion <NUM> and the occupant <NUM>.

An additional configuration of the driver's seat airbag device <NUM> will be described. <FIG> is a diagram illustrating the variant steering wheel <NUM> of <FIG> from each direction. <FIG> is an enlarged view of the variant steering wheel <NUM> of <FIG>. In the present embodiment, for consideration of safety aspects during expansion and deployment of the cushion <NUM> (see <FIG>, and the like), and for further improvement of occupant restraint performance, an ingenious design is applied to the cover member <NUM> of the hub <NUM>.

The cover member <NUM> is configured to have a cover door <NUM> formed when the cushion <NUM> is expanded and deployed. The cover door <NUM> of the present embodiment comprises a large portion of the design region <NUM> of the cover member <NUM> that opens as a single door. The shape of the cover door <NUM> is defined by a groove part <NUM> carved into the back of the design region.

<FIG> is a cross-sectional view taken along line B-B of the hub <NUM> of the variant steering wheel <NUM> in <FIG>. As illustrated in <FIG>, a cleavage-inducing groove part <NUM> is formed into the back of the design region of the cover member <NUM>.

<FIG> is a diagram illustrating the cover member <NUM> in <FIG> in an opened state. <FIG> illustrates the area around the hub <NUM> of the variant steering wheel <NUM> omitting the cushion <NUM>. The cover member <NUM> of the present embodiment comprises one cover door <NUM> that opens upwardly toward the hub <NUM> when the groove part <NUM> (see <FIG>) is opened by the expansion pressure of the cushion <NUM>. At this time, a hinge <NUM> is formed in the cover member <NUM> to connect the body of the cover member <NUM> to the cover door <NUM> so that the cover door <NUM> does not shatter.

The upwardly opening cover door <NUM> of the present embodiment can also avoid contact with the rim <NUM> and switch-type objects on either side of and below the hub <NUM>. By reducing the opportunity for the cover door <NUM> to contact a structure such as the rim <NUM>, it is possible to prevent the cover door <NUM> from falling off due to impact or the like, thereby further enhancing safety.

The cover door <NUM> can be used as a supporting surface for the cushion <NUM>. A cover door <NUM> that opens upwardly can support the upper front side of the cushion <NUM> and provide a downwardly directed reaction force against the cushion <NUM> on the occupant side. In other words, a cover door <NUM> that opens upwardly is less likely to push up the cushion <NUM> than a cover door that opens downwardly.

As explained with reference to <FIG>, by expanding and deploying the cushion <NUM> toward the rear lower side, the cushion <NUM> can be placed between the variant steering wheel <NUM> and the abdomen <NUM> and <NUM> of the occupant <NUM>, and the cushion <NUM> can be sandwiched between the variant steering wheel <NUM> and the abdomen <NUM> of the occupant <NUM>, thereby making the orientation of the cushion <NUM> to collapse less readily and improving the restraining performance of the cushion <NUM> relative to the head <NUM> of the occupant <NUM>. The behavior of the cushion <NUM> of moving toward the rearward lower side of the cushion <NUM> is less likely to contact the head <NUM> of the occupant <NUM> from below than the behavior of moving toward the rearward upper side of the cushion <NUM>, thus preventing backward retroflexing of the head <NUM> of the occupant <NUM>, and other movements of the head <NUM> that are likely to cause strain. In particular, since the cushion <NUM> tends to contact the head <NUM> of an out-of-position occupant <NUM> described above from below, it is extremely effective to generate rear-downward behavior of the cushion <NUM>.

In order to efficiently open the cover door <NUM> upwardly, it is also effective to make the lower range of the cover member <NUM> of the groove part <NUM> (see <FIG>) deeper than the upper range. According to this configuration, the groove part <NUM> induces cleavage first in the lower range before the upper range, and the cleavage speed is also faster, so that the cover door <NUM> can efficiently generate an upward movement.

As described above, according to the present embodiment, a driver's seat airbag device <NUM> capable of fully restraining an occupant <NUM> while giving consideration to safety aspects during expansion and deployment can be achieved.

Modified examples of each of the above-described components are described below. In each of the diagrams <FIG>, the same sign is attached to the same elements as those already described, and the description of the previously mentioned elements are 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.

<FIG> is a diagram illustrating a first modified example (airbag module <NUM>) and a second modified example (airbag module <NUM>) of the airbag module <NUM> in <FIG>. <FIG> illustrates the airbag module <NUM>. In the airbag module <NUM>, the rear end side 150b of the cloth member is inserted and fastened into a gap in the wound or folded cushion <NUM>. This configuration also enables the airbag module <NUM> in stowed form to prevent the cloth member <NUM> from being misaligned while stowed and to efficiently deploy the cloth member <NUM> at a desired position.

<FIG> illustrates the airbag module <NUM>. In <FIG>, hatching of the cushion <NUM> is omitted. In the airbag module <NUM>, the cloth member <NUM> is fastened so that the rear end side 150b is inserted into a gap in the folded cushion <NUM>, and is sandwiched between the cushion <NUM> and the inflator <NUM>. This configuration also enables the airbag module <NUM> in stowed form to prevent misalignment of the cloth member <NUM> while stowed and to efficiently deploy the cloth member <NUM> at a desired position.

<FIG> is a diagram illustrating a third modified example of the airbag module <NUM> in <FIG> (airbag module <NUM>). <FIG> illustrates the airbag module <NUM>, corresponding to <FIG>. A cloth member <NUM> provided by the airbag module <NUM> is fastened on both ends to the stud bolts 118a and 118b, and is configured with a fragile part <NUM> formed at a prescribed location that breaks under the expansion pressure of the cushion <NUM>.

<FIG> is a diagram illustrating the cloth member <NUM> corresponding to <FIG>. The cloth member <NUM> has holes 246a and 246b for fastening to the stud bolts <NUM> of the inflator <NUM> not only on a first end side 242a, but also on a second end side 242b. The fragile part <NUM> is implemented by, for example, providing a fine slit in a broken line at a point near the second end side 242b.

As illustrated in <FIG>, the cloth member <NUM> has the first end side 242a connected to the stud bolt 118a of the inflator <NUM>, and the second end side 242b connected to the stud bolt 118b across the cover member <NUM> side of the cushion <NUM> in stowed form from the first end side 242a. For the cloth member <NUM>, misalignment of the cushion while stowed can be efficiently prevented. As the cushion <NUM> begins to expand and deploy, the fragile part <NUM> of the cloth member <NUM> breaks and the prescribed range of the rear end side 150b becomes a free end state. This configuration also allows the cloth member <NUM> to be passed over the top of the cushion <NUM> when the cushion <NUM> is expanded and deployed. Similar to the cloth member <NUM> of <FIG>, the cloth member <NUM> can also suppress the behavior of the cushion <NUM> attempting to move toward the head <NUM> of the occupant <NUM>, or suppress the load when the cushion <NUM> contacts the head <NUM>, and prevent the head <NUM> from being pushed up and retroflexed backward.

The fragile part <NUM> can be implemented by providing a fine slit, but can also be achieved by other configurations. For example, if a single cloth member is achieved by connecting two pieces of cloth with a breakable thread, or by welding them to a breakable degree, the connection or welding portion functions as the fragile part described above.

In addition to a fragile part that can be broken, such as a breaking part <NUM> [sic], the same function as the breaking part can be achieved by an engaging part that can be released by the expansion pressure of the cushion <NUM>. For example, if a protrusion with a retainer is provided on one of the two pieces of cloth, and a slit or the like is provided on the other to capture the protrusion, and these protrusions and slits are engaged to achieve a single cloth member, the engaging part can be released by the expansion pressure of the cushion <NUM> to enable deployment of the cloth member.

In each of the cloth members described above, in addition to the configuration in which the end parts are fastened to the stud bolts <NUM> of the inflator <NUM>, the ends can be connected and secured to the vehicle front side of the cushion <NUM> by sewing or the like. At that time, for example, even by connecting one end of the cloth member to the cushion <NUM> by sewing, which is easy to break or unravel, that connection point can be caused to function as the fragile part described above.

<FIG> is a diagram illustrating a fourth modified example of the airbag module <NUM> in <FIG> (airbag module <NUM>). <FIG> illustrates the internal structure of the cushion <NUM> through each panel of the cushion <NUM> of <FIG>. In the airbag module <NUM>, the cushion <NUM> is provided with a rectifying cloth <NUM> as a new internal structure.

The rectifying cloth <NUM> is a member that directs the gas of the inflator <NUM> (see <FIG>) in a particular direction, and is connected to the rear panel <NUM> at the interior of the cushion <NUM>, covering the portion having the gas discharge port <NUM> of the inserted inflator <NUM>. The flow-regulating material <NUM> has an opening portion <NUM> below the inflator <NUM> that discharges gas, and small diameter exhaust ports 366a, 366b (see <FIG>) on side portions that also discharge gas.

<FIG> is a diagram illustrating the flow-regulating material <NUM> in <FIG> from a side. The flow-regulating material <NUM> is formed in a bag shape by stitching, and a lower side edge is open to form an opening portion <NUM>.

<FIG> illustrates a state where the flow-regulating material <NUM> of <FIG> unstitched and spread out on a plane. The rectifying cloth <NUM> is provided with an insertion opening <NUM> in the center through which a portion of the inflator <NUM> (see <FIG>) is inserted, and is secured to the module installation surface (see <FIG>) together with the rear panel <NUM> by the stud bolts <NUM> of the inflator <NUM>. Exhaust ports 366a, 366b are provided at two locations on left and right sides to supply gas in the vicinity of the center of the cushion <NUM>. The aperture <NUM> is formed to a larger diameter than the exhaust ports 366a and 366b and allows more gas to pass through than the exhaust ports 366a and 366b.

With the rectifying cloth <NUM> described above, the gas supplied from the inflator <NUM> is preferentially supplied to the lower portion 104b of the cushion <NUM> (<FIG>) through the aperture <NUM>. As a result, the cushion <NUM> expands and deploys preferentially from the lower 104b side. According to this configuration, the cushion <NUM> allows the lower portion 104b to enter between the variant steering wheel <NUM> and the abdomen <NUM> of the occupant <NUM> at an early stage and to be sandwiched between the variant steering wheel <NUM> and the abdomen <NUM>.

<FIG> is a diagram illustrating a fifth modified example of the airbag module <NUM> in <FIG> (airbag module <NUM>). <FIG> illustrates an airbag module <NUM>, corresponding to <FIG>. The cushion <NUM> provided with airbag module <NUM> differs in configuration from that of cushion <NUM> of <FIG> in that two panel members, front panel <NUM>, and rear panel <NUM>, are provided, in other words, side panel <NUM> is omitted. The cloth member <NUM> is also provided for the cushion <NUM>.

<FIG> is a diagram illustrating the front panel <NUM> of <FIG>. The front panel <NUM> is circular in shape. <FIG> is a diagram illustrating the rear panel <NUM> of <FIG>. The rear panel <NUM> is circular and is formed to approximately the same dimensions as the front panel <NUM>. The cushion <NUM> of <FIG> can be formed by joining the edge of the front panel <NUM> to the edge of the rear panel <NUM>.

In the airbag module <NUM> of this configuration (see <FIG>), by applying the cloth member <NUM> over the upper portion of the cushion <NUM>, similar to the airbag module <NUM> of <FIG>, behavior of the cushion <NUM> during deployment of attempting to move toward the head <NUM> of the occupant <NUM> can be suppressed, or the load when the cushion <NUM> contacts the head <NUM> can be suppressed; thus preventing the head <NUM> from being pushed up and retroflexed backward. In the airbag module <NUM>, as in the airbag module <NUM> of <FIG>, by using a stowed form with the center of the front panel <NUM> as the apex, the portion of the cushion <NUM> that is centered on the occupant side can be positioned on the cover member <NUM> side.

<FIG> is a diagram illustrating a sixth modified example of the airbag module <NUM> in <FIG> (airbag module <NUM>). <FIG> illustrates an airbag module <NUM>, corresponding to <FIG>. Similar to the cushion <NUM> of <FIG>, a cushion <NUM> provided with the airbag module <NUM> is composed of two panel members, a front panel <NUM> and a rear panel <NUM>, but differs from the cushion <NUM> in that the front panel <NUM> and the rear panel <NUM> are rectangular.

<FIG> is a diagram illustrating the front panel <NUM> of <FIG>. The front panel <NUM> is formed in a near square shape. <FIG> is a diagram illustrating the rear panel <NUM> of <FIG>. The rear panel <NUM> is also nearly square in shape and is formed to approximately the same dimensions as the front panel <NUM>. When forming the cushion <NUM> of <FIG>, one of the front panels <NUM> or rear panels <NUM> is tilted at about <NUM>° to the other and joined edge to edge with each other.

In the airbag module <NUM> of these configurations (see <FIG>), by applying the cloth member <NUM> over the upper portion of the cushion <NUM>, similar to the airbag module <NUM> of <FIG>, it is possible to suppress the behavior of the cushion <NUM> during deployment attempting to move toward the head <NUM> of the occupant <NUM>, or suppress the load when the cushion <NUM> contacts the head <NUM>, and prevent the head <NUM> from being pushed up and retroflexed backward. In the airbag module <NUM>, as in the airbag module <NUM> of <FIG>, by using a stowed form with the center of the front panel <NUM> as the apex, the portion of the cushion <NUM> that is centered on the occupant side can be positioned on the cover member <NUM> side.

<FIG> is a diagram illustrating a first modified example (cover member <NUM>) and a second modified example (cover member <NUM>) of the cover member <NUM> in <FIG>. These cover members <NUM> and <NUM> are different in configuration from the cover member <NUM>, regarding the shape of the cover door.

<FIG> is a diagram illustrating a cover member <NUM>. The cover member <NUM> comprises two cover doors 404a and 404b on the left and right sides formed by a groove part <NUM>. The cover doors 404a and 404b are formed by bisecting a design region <NUM> of the cover member <NUM> into left and right sides, such that an emblem <NUM> is included in the left side cover door 404a. The cover member <NUM> is formed with hinges 410a and 410b that connect the body of the cover <NUM> to the cover doors 404a and 404b so that the cover doors 404a and 404b do not fly away.

In the cover member <NUM>, when the groove part <NUM> is opened by the expansion pressure of the cushion <NUM> (see <FIG>), the two cover doors 404a and 404b respectively open upwards. The upwardly-opening cover doors 404a and 404b are less likely to push up the cushion <NUM> than downwardly-opening cover doors, and provide a downward reaction force to the cushion <NUM>, thereby suppressing the deployment behavior of the cushion <NUM> attempting to move toward the head <NUM> of the occupant <NUM> (see <FIG>).

<FIG> is a diagram illustrating the cover member <NUM>. The cover member <NUM> also comprises two cover doors 424a and 424b that bisect the design region <NUM> into left and right sides by a groove part <NUM>. The cover doors 424a and 424b are configured to open toward each of the left and right diagonally upward directions when viewed from the center of the hub <NUM>.

Hinges 444a and 444b are formed at respective locations diagonally upwardly away from the center of the hub <NUM>. Even the cover doors 424a and 424b, which open diagonally upward from right to left, provide a downward reaction force against the cushion <NUM>, so that it is difficult to push up the cushion <NUM> compared to a downwardly-opening cover door, thereby suppressing the deployment behavior of the cushion <NUM> attempting to move toward the head <NUM> of the occupant <NUM> (see <FIG>).

<FIG> is a diagram illustrating a seventh modified example (airbag module <NUM>) and an eighth modified example (airbag module <NUM>) of the airbag module <NUM> in <FIG>. <FIG> illustrates an airbag module <NUM> of the seventh modified example. The front end side 150a of the cloth member <NUM> can also be connected to the wall part <NUM> of the cover member, for example, as a part that makes up the variant steering wheel <NUM>. The front end side 150a of the cloth member <NUM> can be connected to the wall part <NUM> by use of a fastener such as a rivet <NUM> or by welding, for example, when the wall part <NUM> is made of resin. This configuration also allows the cloth member <NUM> to be applied to the top of the expanding and deploying cushion <NUM>.

<FIG> illustrates an airbag module <NUM> of the eighth modified example. The front end side 150a of the cloth member <NUM> can also be connected to the module installation surface <NUM>, for example, as a part that makes up the variant steering wheel <NUM>. The front end side 150a of the cloth member <NUM> can be connected to the module installation surface <NUM> using a bolted bracket <NUM>. With the bracket <NUM>, whether the module installation surface <NUM> is made of metal or resin, providing support is feasible. When the module installation surface <NUM> is made of resin, the front end side 150a of the cloth member <NUM> can be connected to the module installation surface <NUM> by welding in addition to the bracket <NUM>. This configuration also allows the cloth member <NUM> to be applied to the top of the expanding and deploying cushion <NUM>.

<FIG> is a diagram illustrating a ninth modified example (airbag module <NUM>) and a tenth modified example (airbag module <NUM>) of the airbag module <NUM> in <FIG>. <FIG> illustrates an airbag module <NUM> of the ninth modified example. The front end side 150a of the cloth member <NUM> can also be sandwiched as a part comprising the variant steering wheel <NUM>, for example, at a point between the cover member <NUM> and a part adjacent to this cover member <NUM>, for example, at the edge of the module installation surface <NUM>. This configuration also allows the front end side 150a of the cloth member <NUM> to be connected to the variant steering wheel <NUM>, and the cloth member <NUM> to be applied to the upper portion of the cushion <NUM> that is expanded and deployed.

<FIG> illustrates an airbag module <NUM> of the tenth modified example. The front end side 150a of the cloth member <NUM> can also be connected to the design region <NUM> of the cover member <NUM>, for example, as a part that makes up the variant steering wheel <NUM>. The front end part 150a of the cloth member <NUM> can be connected to the design region <NUM> by, for example, welding or the like to the design region <NUM> together with a prescribed emblem <NUM>.

As described with reference to <FIG>, the cover member <NUM> comprises one cover door <NUM> that opens upwardly. This cover door <NUM> is formed by including an emblem <NUM>. Accordingly, when the cushion <NUM> is expanded, the front end side 150a of the cloth member <NUM> is positioned above the cushion <NUM>. Therefore, this configuration also allows the cloth member <NUM> to be suspended on top of the expanding cushion <NUM>. Otherwise, the front end part 150a of the cloth member <NUM> can be connected not only to the area that will be the cover door <NUM>, but also to the area above the cover door <NUM> in the design region <NUM> by welding or riveting. According to this configuration, regardless of the direction in which the cover door <NUM> is opened, the front end side 150a of the cloth member <NUM> can be positioned above the cushion <NUM>, and the cloth member can be suspended on the upper portion of the cushion to be expanded and deployed.

<FIG> is a diagram illustrating an eleventh modified example of the airbag module <NUM> in <FIG> (airbag module <NUM>). <FIG> is a perspective view of the airbag module <NUM> in stowed form, corresponding to <FIG>. In the present modified example, the configuration differs from the above examples in that a folding part <NUM> is provided in the middle of the cloth member <NUM>. The folding part <NUM> is formed by folding a midway point of the longitudinal side of the cloth member <NUM> in a pleated manner.

<FIG> is a cross-sectional view of the airbag module <NUM> corresponding to <FIG>. As illustrated in <FIG>, the folding part <NUM> is folded so as to be sandwiched between the apex <NUM> of the cushion <NUM> and the design region <NUM> of the cover member <NUM>. This configuration allows the cloth member <NUM> while stowed to be shortened for the airbag module <NUM> while preventing the cloth member <NUM> from shifting position while stowed. In addition, with the folding part <NUM> overlapping the apex <NUM> of the cushion <NUM>, the cloth member <NUM> can be smoothly deployed by suitably releasing the folding part <NUM> as the cushion <NUM> expands and deploys.

<FIG> is a diagram illustrating a twelfth modified example of the airbag module <NUM> in <FIG> (airbag module <NUM>). <FIG> is a perspective view of the airbag module <NUM> in stored form, corresponding to <FIG>. In the present modified example, the configuration differs from the above examples in that the cloth member <NUM> is provided with a temporary fastening part <NUM> in addition to the folding part <NUM>. The temporary fastening part <NUM> is provided for temporarily fastening the folding part <NUM>.

<FIG> is a cross-sectional view of the airbag module <NUM> corresponding to <FIG>. The temporary fastening part <NUM> is formed so as to enable being released by the expansion pressure of the cushion <NUM>. For example, the temporary fastening part <NUM> is formed by sewing that can be broken by the expansion pressure of the cushion <NUM>. The temporary fastening part <NUM>, together with the folding part <NUM>, is sandwiched between the apex <NUM> of the cushion <NUM> and the design region <NUM> of the cover member <NUM>. Therefore, the temporary fastening part <NUM> can easily apply force during the expansion and deployment of the cushion <NUM> and can be smoothly released.

With the configuration of the airbag module <NUM> described above, the cloth member <NUM> can be shortened and prevented from being displaced while stowed by the folding portion <NUM> and the temporary fastening part <NUM>, while the cloth member <NUM> can be smoothly deployed by releasing the temporary fastening part <NUM> during expansion and deployment of the cushion <NUM>. The temporary fastening part <NUM> is not limited to breakable sewing, but can also be realized by, for example, bonding or heat welding that can be peeled off by the expansion pressure of the cushion <NUM>.

<FIG> is a diagram illustrating a thirteenth modified example (airbag module <NUM>) of the airbag module <NUM> in <FIG>. <FIG> is a perspective view of the airbag module <NUM> corresponding to <FIG>. In this modified example, the configuration differs from the above examples in that the static frictional force on the occupant side of a cloth member <NUM> is enhanced to make slipping difficult.

The cloth member <NUM> has a configuration in which the static coefficient of friction of the surface on the occupant side is greater than the static coefficient of friction of the surface on the cushion side. For example, the cloth member <NUM> has a resin coated surface <NUM> on the occupant side. The resin-coated surface <NUM> is coated with silicone (as an example of a type of resin), and has a large static frictional force against the occupant <NUM> (<FIG>), causing slipping against the occupant <NUM> to occur less readily. Accordingly, with the airbag module <NUM>, when the cloth member <NUM> contacts the occupant <NUM>, the cloth member <NUM> and the cushion <NUM> are prevented from slipping off the occupant <NUM>, and the cloth member <NUM> appropriately exerts the function of preventing the head <NUM> of the occupant <NUM> from being pushed up, while enabling the cushion <NUM> to fully restrain the occupant <NUM> [sic].

<FIG> shows the test results of evaluating cloth members with different static friction coefficients. The tests were performed on a total of <NUM> samples from A to K. Each cloth member sample has a different amount of silicon applied. The tests were performed on the measurement of the coefficient of static friction, the evaluation of the injury value of the occupant <NUM> (see <FIG>) in a non-normal seating position (out of position (OOP)), and the evaluation of the deployment behavior of the cushion <NUM>. As explained with reference to <FIG>, the non-normal seating position assumes that the occupant <NUM> is leaning out of the seat.

The measurement of the coefficient of static friction of the cloth member was carried out in accordance with ISO <NUM> by preparing two sample pieces of the same type of cloth member, securing one side to the test table, and strapping the other side to a sliding piece of the testing machine, and sliding the sliding piece in motion on the test table. The two sample pieces of the cloth member were fixed to the test table and the slip piece, respectively, so that the occupant-side surfaces were in contact with each other. The injury values and deployment behavior of the occupant <NUM> were also analyzed using computer simulations.

As shown in <FIG>, the OOP injury values performed well on and after sample D, where the static friction coefficient was greater than <NUM>. This is because when the static friction coefficient of the cloth member is less than <NUM>, when the cloth member is pressed against the abdomen <NUM> of the occupant <NUM> (see <FIG>) while the cushion <NUM> expands and deploys, the cloth member slips and the cushion <NUM> expands upward as is, pushing up the chin of the occupant <NUM>.

The deployment behavior of the cushion <NUM> performed well on and before sample I. This was because when the coefficient of static friction of the cloth member was higher than a certain level, excessive static frictional force was generated between the cloth member and the cover member <NUM> (<FIG>) when the cushion <NUM> expanded and deployed, and the cloth member altered the deployment behavior of the cushion <NUM>.

From the above, the coefficient of static friction on the occupant side of the cloth member was confirmed to be favorable when within the range of values from <NUM> to <NUM>. If the cloth member is within this range, the cushion <NUM> can fully restrain the occupant <NUM> while preventing slipping way from the occupant <NUM> upon contact with the occupant <NUM> (see <FIG>), and suitably preventing the head <NUM> from being pushed up and retroflexed backward by suppressing the deployment behavior of the cushion <NUM> toward the head <NUM> of the occupant <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.

Claim 1:
A driver's seat airbag device comprising:
a vehicle steering wheel; and
an airbag module (<NUM>) stowed in the steering wheel containing an inflator (<NUM>) and an airbag cushion (<NUM>), said airbag cushion (<NUM>) comprising a front panel (<NUM>) forming the restraining surface for an occupant, and having an upper portion (104a) when in its deployed state, wherein
the steering wheel has a module installation surface (<NUM>) on which the airbag module (<NUM>) is installed and a cover member (<NUM>) that covers the airbag module (<NUM>) installed on the module installation surface (<NUM>);
the cover member (<NUM>) is formed with one or a plurality of cover doors (<NUM>) that open upon receiving expansion pressure from the airbag cushion (<NUM>);
the airbag module (<NUM>) further includes a cloth member (<NUM>) being connected on the front end side to the inflator (<NUM>), or the vehicle front side of the airbag cushion (<NUM>), or a prescribed location of the steering wheel, wherein the rear end side (150b) of the cloth member (<NUM>) is a free end when the airbag cushion (<NUM>) in not deployed;
in the airbag module (<NUM>), the airbag cushion (<NUM>) is put into a stowed form, such as being wound up or folded, the cloth member (<NUM>) is suspended across the cover member side of the airbag cushion (<NUM>) in stowed form; and the cover member (<NUM>) is laid on top of the cloth member (<NUM>);
characterized in that
the cloth member (<NUM>) hangs on and is suspended on the upper portion (104a) of the airbag cushion (<NUM>) upon expansion and deployment and passes from the upper portion (104a) of the airbag cushion (<NUM>) to the front panel (<NUM>), such that the upper portion (104a) of the airbag cushion (<NUM>) is covered with the cloth member (<NUM>) and the rear end side (150b) of the cloth member (<NUM>) is in a position to be sandwiched between the chest of the occupant and the airbag cushion (<NUM>).