Patent ID: 12202431

EMBODIMENTS OF THE INVENTION

The airbag device according to the embodiment of the present disclosure will be described in detail according to the drawings below. The airbag device according to the embodiment of the present invention is equipped to a seat of a vehicle.

The “vertical direction” of the vehicle referred to in the descriptions below indicates a direction on a line connecting the center of the roof of the vehicle to the center of the floor of the vehicle, where the direction toward the roof is “upper” and the direction toward the floor is “lower”. Additionally, the “front-to-back direction” refers to the direction in which the vehicle travels, where the advancing direction is the “front direction” and the reverse direction is the “back direction”. Furthermore, the “vehicle width direction” is the direction orthogonal to the “front-to-back direction” described above, and is the direction in which the regular seats are arranged in a line in the passenger compartment.

FIG.1is a perspective view schematically illustrating the interior of a passenger compartment1in which the airbag device4according to the embodiment is installed.FIG.1depicts a driver seat2and a passenger seat3installed on a floor10of a passenger compartment1, as well as a seatbelt23equipped in the driver seat2. The driver seat2includes a seat portion21and a backrest22that rises upward from the rear side of the seat portion21, and an occupant20(seeFIG.4) is seated on the seat part21with the seatbelt23buckled in.

The airbag device4according to the embodiment is incorporated into the side of the passenger seat3side of the backrest22of the driver seat2.FIG.2is a cross section view of the airbag device4along line II-II inFIG.1. The vertical direction in this drawing corresponds to the “front-to-back direction” described above.

The airbag device4includes an airbag cushion5and an inflator6that are stowed in the stowage part40. The stowage part40is a box body provided with an outward opening on the side surface of the passenger seat3side (left side inFIG.2) of the backrest22, and is configured, for example, using a portion of the backrest22skeleton frame. The opening of the stowage part40is covered by a cover plate41which is flush with the side surface of the backrest22. The cover plate41is a resin plate of lower strength than the stowage part40, and a cleavage groove42is formed on the inner surface of the front portion (upper portion inFIG.2) of the cover plate41extending in the vertical direction.

The airbag cushion5is, for example, a bag body made of cloth reinforced by weaving in high-strength fibers such as nylon fiber or the like, and stowed inside the stowage part40in a folded state. The inflator6is cylindrical in shape and is mounted inside the airbag cushion5. A stud bolt60protruding radially outward is mounted on the circumferential surface of the inflator6and this stud bolt60passes through a stud hole532(seeFIG.7) and extends outside the airbag cushion5.

The inflator6is secured by tightening a nut61onto the stud bolt60passed through the bottom plate of the stowage part40, and the airbag cushion5is secured by being sandwiched between the inflator6and the bottom plate of the stowage part40at the stowage position of the inflator.

The inflator6is activated in the event of an emergency such as a vehicle collision and the like and injects gas for expansion and deployment into the airbag cushion5. The airbag cushion5expands explosively under the action of the injected gas of the inflator6, ruptures the cover plate41at the position of the cleavage groove42, and expands outwardly as a support for the stowage part40.

FIG.3is a perspective view of the airbag cushion5depicting the form thereof during expansion and deployment. As depicted inFIG.3, the airbag cushion5includes a main deployment part53and a protruding part54that protrudes upwards from the center part of the upper surface of the main deployment part53. In other words, the airbag cushion5is composed of an upper surface panel50, an opposing lower surface panel51separated in the vertical direction, and a cylindrical shaped side surface panel52(first panel) that connects the periphery of the upper surface panel50and the lower surface panel51(second panel, bottom surface panel).

The side surface panel52is composed of a front side surface panel521and a rear side surface panel522separated and opposed in the front-to-back direction. The front side surface panel521is arranged more forward than the rear side surface panel522. The edges of the front side surface panel521and the rear side surface panel522are sewn together, forming a cylindrical shape.

The upper surface panel50, lower surface panel51, and side surface panel52are integrally joined by having their respective edges sewn together and as depicted in the figures, constitute the main deployment part53that deploys as a rectangular body elongated in the left-right direction (vehicle width direction). The protruding part54rises upward at the center in the length direction of the upper surface panel50, and deploys with an appropriate width in the left-right direction.

As depicted by a dashed line in the figures, the inflator6is stowed along the inner surface of the rear side surface panel522with the axial direction set to the vertical direction. Two stud bolts60used for the aforementioned securing are provided on the inflator6separated in the vertical direction and each protrude through stud holes532to the outside of the rear side surface panel522.

FIG.4is a front view depicting the deployed state of the airbag cushion5in the passenger compartment1as seen from the front. As described above, the airbag cushion5is stowed in the side part of the backrest22of the driver seat2, and in the event of an emergency such as a vehicle collision or the like, expands under the action of the gas injected by the inflator6and deploys between the driver seat2and the passenger seat3which are adjacent to each other in the vehicle width direction.

The main deployment part53composed of the upper surface panel50, the lower surface panel51, and the side surface panel52extends laterally at a height position corresponding to the waist and shoulder of the occupant20seated in the driver seat2and the occupant30seated in the passenger seat3, and restrains the occupants20and30from the side on both sides reaching the front position of the driver seat2and the passenger seat3. Accordingly, lateral movement of the occupants20and30during a side collision can be prevented and the occupants20and30can be effectively protected. Note that the occupants20and30inFIG.4are schematically illustrated by a two-dot chain line.

The protruding part54rises upward in the center of the main deployment part53and reaches a height position corresponding to the heads of the occupant20seated in the driver seat2and the occupant30seated in the passenger seat3. Therefore, even if, for example, the occupant30sitting in the passenger seat3is OOP (Out of Position), the head of the occupant30moving laterally towards the driver seat2can be restrained by the protruding part54.

An insertion passage55is formed at the seam of the rear side surface panel522and lower surface panel51enabling insertion of the inflator6into the airbag cushion5.FIG.5is an enlarged diagram depicting the part of the airbag cushion5near the insertion passage55andFIG.6is a vertical cross section view along the line VI-VI ofFIG.5. For convenience, the stud holes532are omitted inFIG.6and the stud bolts60are depicted as virtual lines (alternate long and short dashed line).

The insertion passage55includes a first piece531provided on the rear side surface panel522extending from a part of the edge of the lower surface panel51and, midway, folded inside the airbag cushion5, and opposite the first piece531, a second piece537provided on the lower surface panel51, and extending from the edge of the rear side surface panel522to the inside of the airbag cushion5. The first piece531has an elongated rectangular shape. The second piece537has a rectangular shape with the dimension in the longitudinal direction shorter than that of the first piece531and the dimension in the width direction substantially equal to that of the first piece531. A folded part538(corresponding part) of the first piece531, folded inside the airbag cushion5has a size substantially equal to the second piece537. The folded part538and the second piece537are positioned opposite each other.

The first piece531is integrally formed with the rear side surface panel522and includes a base part534and the folded part538. Furthermore, the first piece531and second piece537are integrally formed. The second piece537is connected to the tip of the first piece531. In other words, on the rear side surface panel522, an extension piece56extends from a part of the edge of the lower surface panel51and the extension piece56includes the first piece531and the second piece537(seeFIG.7andFIG.8).

In addition, a through hole533(internal opening) that is for example slit shaped, is formed at the border of the first piece531and the second piece537, in other words, penetrating in the thickness direction between the folded part538and the second piece537. The folded part538and the second piece537are separated using the through hole533as a reference. The length of the edge of the through hole533is substantially equal to the length of the outer periphery of a main body part63of the inflator6, described below.

In other words, the extension piece56is first folded towards the inside of the airbag cushion5at a position slightly separated from the base part534and then folded again at the through hole533causing the folded part538and the second piece537to face each other. The end part of the extension piece56(second piece537) is sewn to the lower surface panel51, as described below.

A first seam536sewing the folded part538and second piece537together is formed in the extension direction of the first piece531, in other words, along the longitudinal direction of the folded part538or second piece537. The first seams536are formed, separated in the width direction of the folded part538or second piece537, along the edges of both long sides of the folded part538and second piece537.

Thus, the insertion passage55, composed of the folded part538and second piece537, is formed extending in the longitudinal direction of the folded part538or second piece537, in other words, from inside to outside the airbag cushion5. With the insertion passage55, the through hole533is opened at a first end, inside the airbag cushion5, and an outer opening535is opened at a second end, outside the airbag cushion5.

In the insertion passage55, the spacing between the first seams536gradually increases moving away from the through hole533. Therefore, the outer opening535is larger than the through hole533.

The inflator6has a cylindrically shaped main body part63and a gas discharge outlet62for injecting gas for expansion and deployment is provided at a first end of the main body part63. The first end of the main body part63of the inflator6is inserted into the insertion passage55; thus, the gas discharge outlet62of said first end is arranged inside the airbag cushion5separated from the through hole533, while a second end is arranged near the outer opening535.

As described above, the spacing between the first seams536gradually increases while moving away from the through hole533so the spacing between the circumferential surface of the main body part63and the second piece537or the folded part538also gradually increases while moving away from the through hole533.

Second seams539a,539b, and539cthat sew together the edge parts of the lower surface panel51are formed on the edge part of the lower surface panel51of the rear side surface panel522excluding the first piece531portion (hereinafter, abbreviated to edge excluding the first piece531), and the edge part of the short side of the second piece537.

In detail, the second seam539aformed in an arc at both corners of the edge part of the second piece537sews together the lower surface panel51, the second piece537, the folded part538, and the base part534. In addition, the second seam539bformed along the end part of the short side of the second piece537sews together only the second piece537and the lower surface panel51. Furthermore, the second seam539cformed along the edge of the rear side surface panel522excluding the first piece531sews together the rear side surface panel522and the lower surface panel51. In particular, the second seam539ais formed so as to intersect the first seams536. The second seam539aoverlaps with the first seams536, enabling preventing of gas leakage.

FIG.7is an explanatory diagram for describing the configuration of the airbag cushion5. For convenience, the upper surface panel50, lower surface panel51, front side surface panel521, and rear side surface panel522, prior to being sewn together, are depicted in simplified form inFIG.7. In addition, the “up, down” and “left, right” in the figure are used in the description below.

FIG.7Adepicts the front side surface panel521and the front side surface panel521includes a rectangular portion constituting the main deployment part53and a narrow rectangular shape extending upward from a center part of a long side of the rectangular portion that constitutes the protruding part54.

FIG.7Bdepicts the rear side surface panel522and the rear side surface panel522includes a rectangular portion that constitutes the main deployment part53. A rectangle portion is provided on an upper long side of the rectangular portion extending upwards from a center part and the long narrow rectangular shape extension piece56is provided extending downward from near the left end part of a lower long side of the rectangular portion. One stud hole532is formed in the rectangular portion and two stud holes532are formed in the extension piece56.

FIG.7Cdepicts the upper surface panel50having a left-right symmetrical shape and the upper edge of the front side surface panel521is sewn to the edge of the upper recession and ridge shape thereof and the upper edge of the rear side surface panel522is sewn to the lower edge thereof.

FIG.7Ddepicts the lower surface panel51which has a roughly inverted trapezoidal shape. The front side surface panel521is sewn to the long edge of the two parallel sides of the lower surface panel51and the rear side surface panel522is sewn to the edge of the short side.

In the present embodiment, a case of configuring the airbag cushion5in a bag shape by sewing together the upper surface panel50, lower surface panel51, front side surface panel521, and rear side surface panel522is described, but is not limited to this case. For example, an arbitrary joining technique such as adhesion or welding can be used.

FIG.8toFIG.11are explanatory diagrams for describing the manufacturing procedure of the airbag device4according to the embodiment. In addition,FIG.8toFIG.11only depict the portions enclosed in dashed lines inFIG.7. The manufacturing method of the airbag device4according to the present Embodiment is described according toFIG.8toFIG.11.

First, the operator prepares the rear side surface panel522depicted inFIG.7B. As depicted inFIG.8, a narrow rectangular shaped extension piece56is provided on the rear side surface panel522extending from a portion of an edge of a long side. Stud holes532are formed in the center part of the extension piece56and in the base part534.

An operator forms a through hole533(seeFIG.9) in a slit shape in the extension direction, in other words, the longitudinal direction in the center part of the extension piece56. The through hole533extends in the width direction of the extension piece56. The extension piece56is divided into the first piece531on the base part534side and the second piece537on the tip end side at the through hole533reference. In other words, the through hole533is formed at the border of the first piece531and the second piece537.

Next, as inFIG.10, the operator folds the second piece537onto the base part534so that the folded part538is on top with the through hole533position as a fold line (see the white arrow inFIG.10). This causes the second piece537to overlap with the folded part538at a position separated from the base part534. The folded part538corresponds to the second piece537. InFIG.10, the second piece537prior to folding is depicted using an alternate long and short dashed line.

Here, a first sewing process, sewing the folded part538and second piece537together is performed in the extension direction of the first piece531, in other words, along the longitudinal direction of the folded part538or second piece537. The first sewing is performed, separated in the width direction of the folded part538or second piece537, along the edges of both long sides of the folded part538and second piece537. Therefore, as inFIG.10, the first sewing forms two first seams536. The first sewing is performed so that the spacing between the first seams536becomes gradually larger moving from the through hole533to the base part534.

With this manner of first sewing, the insertion passage55is formed extending in the longitudinal direction of the folded part538or second piece537. At the current point, the through hole533is open at the first end of the insertion passage55and the second end of the insertion passage55is open to the base part534. This open end becomes the outer opening535already described. As described above, the outer opening535is larger than the through hole533.

Next, as depicted inFIG.11, with the second piece537as-is in the overlapping state, the operator folds the folded part538so as to face the base part534(see the white arrow inFIG.11). InFIG.11, the folded part538prior to folding is depicted with a two-dot chain line. Here, the two stud holes532overlap, the folded part538overlaps on the base part534, and the second piece537overlaps on the folded part538.

In this state, the operator places the lower surface panel51on the second piece537and performs the second sewing process, sewing the rear side surface panel522, folded part538, second piece537, and lower surface panel51. InFIG.11, the lower surface panel51is depicted using an alternate long and short dashed line. The second seams539a,539b, and539care formed in the second sewing.

In other words, the second seam539athat sews together the lower surface panel51, the second piece537, the folded part538, and the base part534, are formed in an arc at both corners of the edge of the second piece537. In addition, the second seam539bthat only sews together the second piece537and the lower surface panel51is formed along the end part of the short side of the second piece537. In addition, the second seam539cthat sews together the rear side surface panel522and the lower surface panel51is formed along the edge part of the rear side surface panel522excluding the base part534. As described above, the second seam539ais formed so as to intersect with the first seams536.

Thereafter, the operator sews the edge of the first long side of the front side surface panel521to the edge of the lower surface panel51. In addition, the operator sews both short side edges of the rectangular portion of the front side surface panel521to both short side edges of the rectangular portion of the rear side surface panel522to configure the cylindrical shaped side surface panel52. Furthermore, the operator sews the upper surface panel50to the edge of the second long side of the front side surface panel521and the edge of the second long side of the rear side surface panel522

The airbag cushion5is formed by means of the work described above.

Next, the operator inserts the inflator6into the insertion passage55of the airbag cushion5. The first end of the main body part63of the inflator6is inserted into the insertion passage55through the outer opening535. The first end of the main body part63passes through the insertion passage55and protrudes from the through hole533into the airbag cushion5. The gas discharge outlet62at the first end of the main body part63is arranged separated from the through hole533and the second end is arranged near the outer opening535.

On the other hand, gas pressure in the airbag cushion5must be increased rapidly during expansion and deployment and gas leakage from between the airbag cushion5and the inflator6(main body part63) must be prevented. A method of attaching a metal fitting such as a so-called steel band in the insertion part of the inflator6of the airbag cushion5is generally used to prevent gas leakage. However, use of this manner of metal fitting increases the number of components, increases the manufacturing cost of the airbag device, and requires a separate process for crimping the metal fitting, causing poor productivity.

The airbag device4according to the embodiment is configured to enable resolving this type of problem. This is described in detail below.

FIG.12is a partial cross section view for schematically describing the expansion process of the airbag cushion5during expansion and deployment.FIG.12depicts the portion inFIG.6enclosed with a dashed line. In addition,FIG.12Adepicts the state just prior to expansion and deployment of the airbag cushion5,FIG.12Bdepicts the state part way through expansion and deployment of the airbag cushion5, andFIG.12Cdepicts the state with expansion and deployment of the airbag cushion5complete.

As described above, the inflator6is inserted into the insertion passage55of the airbag cushion5and with the insertion passage55, the outer opening535is larger than the through hole533where the spacing between the inner surface of the insertion passage55and the main body part63of the inflator6gradually increases approaching the outer opening535from the through hole533. In other words, the insertion passage55has a conical shape with the diameter reducing from the outside of the airbag cushion5inwards.

This type of spacing between the inner surface of the insertion passage55and the main body part63of the inflator6is maintained prior to expansion and deployment of the airbag cushion5where the lower surface panel51faces the rear side surface panel522and the inflator6is interposed between the lower surface panel51and the rear side surface panel522(seeFIG.12A).

Expansion and deployment of the airbag cushion5starts when the inflator6starts to inject gas. As described above, the gas discharge outlet62of the inflator6is separated from the through hole533so the discharge direction of the gas from the gas discharge outlet62will not be directed towards the through hole533. In other words, gas discharge will not enlarge the through hole533.

As depicted inFIG.12B, the discharged gas rapidly moves along the inner surface of the airbag cushion5. In other words, gas pressure is applied to the insertion passage55starting from the outer surface of the outer opening535. Also, the insertion passage55has a conical shape with the diameter thereof reduced from the outside toward the inside of the airbag cushion5so as inFIG.12B, gas flow is guided through the outer surface of the insertion passage55from the outer opening535toward the through hole533. Here, the gas applies pressure on the inflator6from all radial directions.

As described above, the insertion passage55is configured by overlapping and sewing of the folded part538and the second piece537and the inflator6is interposed between the folded part538and the second piece537. Therefore, gas pressure applied on the insertion passage55is applied in the direction of bringing the folded part538and the second piece537closer together. Therefore, the spacing between the folded part538and the second piece537, in other words, the inner surface of the insertion passage55and the inflator6, becomes narrower.

As gas pressure inside the airbag cushion5increases, the spacing between the inner surface of the insertion passage55and the inflator6becomes narrower and the spacing between the lower surface panel51and the rear side surface panel522widens. When expansion and deployment of the airbag cushion5is complete, the spacing between the inner surface of the insertion passage55and the inflator6is eliminated, closing the insertion passage55and the spacing between the lower surface panel51and the rear side surface panel522widens so as to roughly form a right angle (seeFIG.12C).

Thereafter, gas discharge from the inflator6is continued. However, the insertion passage55is closed so gas pressure inside the airbag cushion5increases even further, causing the insertion passage55to tighten even further. Therefore, gas leakage can be reliably prevented.

As described above, with the airbag device4according to the embodiment, the insertion passage55fulfills the role of a so-called check valve and can prevent gas leakage from inside the airbag cushion5to outside. Thus, there is no need to provide a separate metal fitting such as a steel band to prevent gas leakage. Therefore, the number of components can be reduced and manufacturing cost of the airbag device4can be lowered, and the process of crimping the metal fitting can be omitted, enabling an increase in productivity.

As described above, with the airbag device4according to the embodiment, the first piece531is integrally formed with the rear side surface panel522; furthermore, the first piece531is integrally formed with the second piece537, enabling reducing labor and increasing workability.

In the above, the case where the side surface panel52is configured using two parts, the front side surface panel521and rear side surface panel522was described as an example, but the present invention is not limited to this case and the side surface panel52can be configured from one panel. In other words, a single rectangular panel with a dimension in the longitudinal direction equal to the sum of the dimensions in the longitudinal direction of the front side surface panel521and the rear side surface panel522may be prepared and a cylindrical shape may be formed by sewing the edges of both short sides of this rectangular panel together.

In addition, in what is described above, the case where the first piece531is integrally formed with the rear side surface panel522and further the first piece531is integrally formed with the second piece537was described as an example, but the present invention is not limited to this case. A case where first piece531and the rear side surface panel522are respectively separate members and the first piece531and second piece537are respectively separate members is feasible, a case where the first piece531and the rear side surface panel522are respectively separate members and only the first piece531and second piece537are integrally formed is feasible, or a case where only the first piece531and the rear side surface panel522are integrally formed and the first piece531and second piece537are respectively separate members is feasible.

EXPLANATION OF CODES

1. Passenger compartment2. Driver seat3. Passenger seat4. Airbag device5. Airbag cushion6. Inflator50. Upper surface panel51. Lower surface panel52. Side surface panel55. Insertion passage56. Extension piece60. Stud bolt62. Gas discharge outlet63. Main body part521. Front side surface panel522. Rear side surface panel531. First piece533. Through hole534. Base part535. Outer opening536. First seam537. Second piece538. Folded part539a,539b,539c. Second seam