Airbag and module

Description of equivalent WO 2004052696 A1

AIRBAG AND MODULE

This invention relates to an airbag module for a passenger side airbag.

An airbag module typically comprises an airbag, an airbag inflator, and a mechanism for initiating the inflation of the airbag. An airbag located on the passenger side of the vehicle may have the airbag inflator placed inside the airbag. The airbag may have an insertion hole sized to receive one end of the airbag inflator.

A tight fit between the hole in airbag and the airbag inflator is desirable to ensure that gas exhausted from the airbag inflator during deployment is retained within the airbag. This tight fit makes the insertion of the airbag inflator into the airbag difficult. During deployment of the airbag, the airbag may slide along the length of the inflator. It is thus necessary to secure the airbag inflator to the airbag to ensure proper deployment of the airbag. An airbag inflator has gas ports in some cases configured around one of its ends. The seams and fabric of the airbag must be protected from the heat of the gas generated by the airbag inflator.

A need exists for a simple airbag module design for a passenger side airbag that may easily accommodate an airbag inflator while still securing the airbag inflator to the airbag and protecting the airbag against hot gases from the inflator.

There is provided in accordance with the present invention

Figure 1 illustrates an airbag of the inventive airbag module, highlighting tabs attached to the airbag.

Figure 2 illustrates the inventive airbag module, including airbag inflator prior to its insertion into airbag.

Figure 3 shows the inventive airbag module of Figures 1 and 2 with airbag inflator inserted into airbag.

Figure 4 illustrates an alternative view of the inventive airbag module with airbag inflator inserted.

Figure 5 illustrates heat shield of inventive airbag module. Figures 6A-6C illustrates an installation of an alternative design of a heat shield to be employed with the inventive airbag module.

Figure 7A illustrates a further step in the installation of the heat shield of Figures 6A-6C.

Figure 7B illustrates the installation of a heat shield onto a side panel of the airbag.

Figure 8A illustrates the heat shield of Figures 6A-6C installed in the airbag module.

Figure 8B illustrates the airbag having an inversion hole to permit the airbag to be sewn inside out.

Figure 9 illustrates the completed airbag module.

Figures 1 and 2 illustrate the inventive airbag module 10. Referring to Figure 1 , an airbag 14 is made of known typically woven fabric and may comprise several panels of fabric that are sewn together. The airbag 14 may be made with three panels, a first side panel 100, a main panel 30, and a second side panel 105. Each side panel 100, 105 may be stitched to the main panel 30. The main panel 30 in addition to providing volume to the airbag covers an airbag inflator 18 to be inserted in airbag 14.

In contrast to known airbags and airbag modules, the airbag 14 has projections 34, here a first tab 38 and a second tab 42, which form a portion of each side panel 100, 105. While the tabs 38, 42 are shown here as part of the side panels 100, 105, the tabs may instead be formed on the main panel 30. The first tab 38 is a protrusion and part of the inboard side panel 100. The second tab 42 is a protrusion and part of the outboard side panel 105. Preferably, the first tab 38 is located near a first hole 46 that extends through the first side panel 100 while the second tab 42 is located near a second hole 50 that extends through the second side panel 105. It is preferable that first tab 38 have a third hole 54 therethrough to match the size of the first hole 46 and the second tab have a fourth hole 60 therethrough sized to match the second hole 50.

Figure 2 shows the airbag 14 as well as the housing 24 and the airbag inflator 18. Here, projections 34, i.e., a first tab 38 and a second tab 42, are pulled through the slots 17 in the housing 24 to extend outside of the housing 24. The housing 24 may comprise steel and have two holes to match the size of the first hole 46 and the second hole 50. The housing 24 serves to protect the airbag 14 and inflator 18.

Tabs 38, 42 permit the easy installation of the airbag inflator 18 into the airbag 14. As shown in Figure 2, the airbag inflator 18 has a first end 22 and a second end 26 and is inserted into the first hole 46 in the airbag 14 along the direction of arrow A. As the airbag inflator 18 is slid into the airbag 14, the first tab 38 may be held in place by applying a force along the direction of arrow B to prevent the movement of the first hole 46 and airbag 14. The first tab 38 further helps slide the airbag 14 and first hole 46 along the airbag inflator 18 during its insertion to prevent bunching of the airbag 14 around the airbag inflator 18. The second tab 42 may be used to adjust the airbag 14 and the second hole 50 around the airbag inflator 18 also.

Figures 3 and 4 illustrate another novel aspect of the airbag module 10. These figures illustrate how the tabs 38, 42 may be folded over the ends of the airbag inflator 18 to secure the airbag 14 to the airbag inflator 18. In Figure 3 the airbag inflator 18 is within the housing 24 and the main panel 30 and the between side panel 100 and the side panel 105. The second end 26, here a threaded end, is inserted into the airbag 14 through the first hole 46 to pass through the second hole 50. The second tab 42 is then folded over the second end 26 such that the fourth hole 60 passes over and encircles the second end 26. Because the second hole 26 and the fourth hole 60 pass over the same end of airbag inflator 18, the second hole 26 and the fourth hole 60 will be matched in size to fit snuggly around the second end 26 of the airbag inflator. By folding over the second tab 42 of the airbag 14 over the second end 26 of the airbag inflator, the second end 26 of the airbag inflator 18 is secured to the airbag 14 through the fourth hole 60. In addition, a washer 70 and nut 74 further secure the airbag inflator 18 to the airbag 14 and housing 24 and further prevent the side panel 105 of the airbag from sliding along the direction of arrow B to uncover the gas exit ports 82. An electrical connector 78 may be attached to the second end 26, as known, to provide a contact for activating the airbag inflator 18.

As shown in Figure 4, the first tab 38 may be folded over the first end 22 of the airbag inflator 18, which is inserted into the airbag 14 and housing 24. Again, the first tab 38 may have a third hole 54 therethrough, which may encircle and secure the first end 22 of the inflator to the airbag 14. Again, because the third hole 54 secures the same end of airbag inflator 18, the first end 22, as the first hole 46, both the third hole 54 and first hole 46 are matched in size to fit securely around this end of the airbag inflator. In this way, the airbag inflator 18 may be held to the airbag 14 without any attachment feature, ensuring proper airbag 14 deployment.

Figure 5 illustrates another important feature of the airbag module 10. The airbag inflator 18 has gas ports 82 (shown in Figure 2), which exhaust hot gas. This hot gas may burn the fabric of an airbag as well as the threads of the airbag that form the seams between panels of the airbag. To prevent damage to the airbag 14 and any potential leakage of gas from the airbag 14, the airbag 14 has a heat shield 64, which may be inserted into the main panel 30 over a seam 86 near the second hole 50 near the anticipated location of the gas ports 82 of the airbag inflator within the airbag 14. The heat shield 64 may comprise fabric, such as the fabric used for the airbag 14, or fabric coated with a heat absorbing material such as silicone, that is folded over and sewn to the main panel 30. The heat shield 64 may have a fifth hole 90 therethrough sized to match the size of the second hole 50 to permit the second end 26 of the airbag inflator to pass therethrough. The heat shield 64 provides an inexpensive way to guard against damage to the airbag 14 and the inadvertent leakage of gas from the airbag 14.

Figures 6A-6C illustrate another heat shield 130 to be used with the inventive airbag module. The main panel 30 is shown prior to its attachment to side the panels 100, 105. The main panel 30 has a first neck 120 and a second neck 124, both portions narrower than the body 126 of the main panel 30. The first neck 120 is longer than the second neck 124 so that ultimately the first neck 120 may be stitched over the second neck 124 as shown in Figure 7A to form the main panel 30 into a loop to which the side panels 100, 105 are stitched. As shown in Figure 6A, the heat shield 130 is sewn at stitch line 138 to the first neck 120. The heat shield 130 comprises a rectangular shaped fabric treated with a heat resistant material such as silicone or neoprene. The heat shield 130 is folded down in the direction of arrow A over itself, creating another shielding insulation layer. To assist in folding the heat shield 130, slits 134 are provided through the heat shield 130 to allow fabric to fold more easily and lay flat. The slits 134 are located where folds lines are to be made.

As shown in Figure 6B, after the heat shield 130 is folded down, a stitch line 142 is added to hold the heat shield 130 in place to the neck 120. Then, the heat shield 130 is folded upward across the neck along the direction of arrow B to create another layer of insulation as illustrated in Figure 6C. Another stitch line 144 is added to sew this layer of the heat shield 130 to the first neck 120. These layers are placed near the anticipated location of the exit ports 82 of an inserted airbag inflator 18. Then, as shown in Figure 7A, the first neck 120 and the second neck 124 are stitched together along with the side panels 100, 105 (not shown in Figure 7A). Figure 7B shows the attachment of a secondary heat shield 150 onto the side panel 105 using stitch lines 160, 170. Figure 8A shows the side panel 105 stitched together with the main panel 30 using stitch line 180. Above the stitch line 180, an additional stitch line 190 is used to attached the heat shield 130 to the secondary heat shield 150 above the stitch line 190.

As generally known, the airbag 14 may be sewn with interior stitches while the airbag is inside out. Figure 8B illustrates the airbag 14 as seen inside out. Normally, such as during airbag deployment, the airbag 14 has a first surface 207 forming the outside surface of the airbag 14 while a second surface 205 forms the interior surface. As illustrated here, however, second surface 205 is shown outside of the first surface 207 (inside out). This technique permits stitch lines to be hidden behind the seams of the airbag.

The stitch line 206 holds the main panel 30 to the side panel 100, to form a seam 210 while the stitch line 208 holds the main panel 30 to the side panel 100 to form a seam 212. To assist in the manufacture of the airbag 14, the airbag 14 is sewn with a gap 230 between the seams 210, 212. The side panel 105, as seen through the gap 230 between the side panel 100 and the main panel 30, is sewn to the main panel 30 without a gap. The first side panel 100, second side panel 105, and the main panel 30 form an airbag volume 216 with a surface 205 forming the exterior surface at this point. When the airbag 14 is almost entirely sewn up, the airbag volume 216 is turned outside out by pulling the second surface 207 through the gap 230 along arrow B so that the second surface 207 now forms the exterior surface of airbag volume 216 and first surface 205 forms the interior. The gap 230 is then sewn shut by a stitch line 200 as shown in Figure 9.

As shown in Figures 1 and 9, the side panels 100, 105, and the main panel 30 form an end portion 204 to receive the airbag inflator 18. The heat shields 130, 150 and reinforcement panels sewn to the end portion 204, as shown in Figure 8, serve to give the end portion 204 a semi-rigid shape that enables the end portion 204 to be placed within the housing 24 and maintain its shape and location there. As a consequence, the airbag inflator 18 may be more easily received by the end portion 204.