Air bag device

Abstract: An air bag device, which is installed in the dashboard of a vehicle, contains a folded air bag (200). One end of an intervening cloth (300) is secured where the air bag (200) is mounted to the air bag device, and the other end is left free. When an inflator (150) is activated to deploy the air bag through the unit door, the air bag generates friction by contacting the unit door (130) or the vehicle's front glass (50). The intervening cloth (300), however, comes in between the air bag and the interior to provide a constant friction, thus allowing smooth deployment of the air bag (200).

Description: Background of the Invention This invention relates to an air bag device installed inside the dashboard on the passenger side of automobiles. Japanese Utility Model Publication No. 3-39326 (1991) and Japanese Laid-Open Patent No. 5-213132 (1993) disclose a type of air bag device that protects people in the vehicle during impact by providing a cover for the outer surface of the air bag. In the above first two examples, however, the air bags are provided only for the drivers. Also, the external covers are intended to reduce the impact on the drivers, and thus do not control the friction of the deploying bag. The latter example, especially, simply prevents direct contact between the air bag and the module cover, and does not facilitate smooth deployment of the bag or maintain a certain level of friction between the air bag and interior elements of the automobile. EP-A-489 174 which belongs to the patent family of Japanese Laid-Open Patent No. 4-055149 teaches a passenger's air bag assembly comprising an air bag with a cloth interposed between the air bag and a dash board cover. The cloth shown therein has a limited extension and its size corresponds exactly to that of the dashboard cover. In fact, as explained at column 2, lines 44-55, the cloth flaps (upon inflation of the air bag) to prevent rubbing between the air bag and the cover. Moreover, the known cloth has a surface which is equal to that of the dashboard cover, so that the cloth will never expand beyond the dashboard cover. JP-A-5-213312 teaches a cloth which is provided on a surface of a driver's air bag and has a limited extension. US-A-3 814 458 relates to a combined heat and kinetic absorption lining for an air bag. US-A-3 814 458 teaches in particular the introduction of a heat and kinetic energy absorbing expansible, but inelastic, further bag within the air bag. Summary of the Invention The object of the air bag device of this invention is to prevent the air bag from coming into direct contact with interior elements and to facilitate smooth and reliable deployment and contraction of the air bag under a constant level of friction during deployment. The above object and further objects which will become apparent hereinafter are achieved by an air bag as defined in claim 1. The air bag device in this invention is equipped with an air bag that is folded and stored within a case, an inflator, a case with a mounting part to secure the open end of the air bag, an intervening cloth attached outside of the air bag and near the mounting part of the air bag case. Air bag devices are required to fully deploy their air bags within a set time period after detecting an impact to the vehicle. Air bags come into contact with elements inside the vehicle and generate various types of friction. Because this invention installs an intervening cloth between the air bag and the interior elements, it secures a constant coefficient of friction. Thus, the air bag can deploy and contract smoothly. Brief Description of the Drawings Figure 1 is an explanatory drawing of the critical part of a vehicle equipped with the invention. Figure 2 shows an appearance of the air bag module. Figure 3 is a component drawing. Figure 4 is a cross section view of the air bag module in an example of the invention. Figure 5 is an example for securing the intervening cloth but is not part of the invention. Figure 6 is an enlarged view of the section A of Figure 4 another example of the invention. Figure 7 is an example for securing the intervening cloth according to the invention. Figure 8 is a cross section view of the mounting structure of the air bag module in the invention. Figure 9 is an explanatory diagram of the functions of the air bag in the invention. Figure 10 is an explanatory diagram of the functions of the air bag in the invention. Figure 11 is an explanatory diagram of the functions of the air bag in another application example of the invention. Figure 12 is an explanatory diagram of the functions of the air bag in another example of the invention. Figure 13 is an explanatory diagrams of the functions of the air bag in another example of the invention. Preferred Embodiments of the Invention Figure 1 is a summary diagram of a vehicle equipped with this invention and Figure 2 is a full view of the air bag module. Inside the vehicle (10), the dashboard (20) is located in front of the driver seat (12) and passenger seat (14). An air bag module (100) is installed inside the dashboard (20) in front of the passenger seat (14). The air bag module (100) in Figure 2 is equipped with a first case (110) and a second case (120) that store an air bag and an inflator, and the first case (110) is equipped with a door (130) at the opening. Figure 3 shows components of the air bag module and Figure 4 is a cross section of the air bag module. The air bag module (100) has a first case (110), which stores the folded air bag (200), and a second case (120), which is connected to the first case (110) and contains an inflator (150). The opening of the first case (110) is covered with a door (130). The door (130) is made of resin or similar materials, and the front surface of the door is covered with the same material as the dashboard (20). It is secured to the first case (110) via flanges (132, 134) that are attached at the back with fasteners such as bolts (135). One flange (134) has a groove (136) that allows the door (130) to open when the air bag (200) is inflated. The first case (110) is a square frame equipped with tabs (112) on the opening end opposite from the door mounting part. The tabs (112) are adapted to secure the open end of the air bag (200). The second case (120) has a cylinder (122), in which the inflator is stored, and the opening end (124) of the case is formed so that it is broader in width. A partition (140) inserted in the opening of the second case (120) has multiple slits (142). This partition (140) secures the inflator (150) and the gas from the inflator travels through the slits (142) to fill the air bag (200). The lower end of the first case (110) is inserted in the space between the leg parts (143) of the partition (140) that is inserted into the second case (120) and the widened part (122) of the second case (120), and is tightened by a fastener (160) to comprise the linking part. The mounting part (210) of the air bag (200) is bent and secured at the linking point of the first case (110) and the second case (120). The inflator (150) has electrical wiring (152) and generates gas. The air bag module of this invention has the above basic structure as well as an intervening cloth (300) installed on the outer surface of the air bag (200) in order to maintain constant friction between the vehicle's interior elements and the air bag (200) during deployment. Figures 5 through 7 show various mounting structures for the intervening cloth (300). In the example shown in Figure 5, which is not part of the claimed invention, the intervening cloth (300) is installed outside of the air bag with its end (310) integrated with the end of the air bag (210) and secured at the linking point of the first case (110) and the second case (120). The tabs (112) of the first case (110) are utilized for securing the pieces. In the application example shown in Figure 6, the intervening cloth (300) is sewed at the stitching positions (320) onto the air bag (200). The stitching positions (320) are positioned near where the air bag is mounted to the case. In the application example shown in Figure 7, the intervening cloth (300) is sewed at the stitching positions (330) in a similar fashion onto the air bag (200). The stitching positions, however, are positioned away from where the air bag (200) is mounted to the case. The free end (340) of the cloth (340) extends to the area near the opening end of the first case (110) when the air bag (200) is deployed. The following describes how this invention functions. Figure 8 shows the condition of the air bag unit (100) that is installed in the dashboard (20) in front of the passenger seat (14) of a vehicle. The air bag unit (100) is secured against a high-strength element (60) of the vehicle on the back of the dashboard (20) with a fastener (126). Figure 9 shows the condition in which the inflator has been ignited and the air bag (200) begins to deploy after the door (130) opens. The air bag (200) deploys in the direction of arrow A by the force of gas filling the bag. At this point, the air bag (200) comes into contact with the inner surface of the door (130), thus causing friction. This friction works to regulate the deployment of the air bag (200). In this invention, the air bag (200) comes into contact with an intervening cloth (300), which is installed outside of the air bag (200), during deployment. The air bag (200) deploys smoothly because the materials of, as well as the coefficient of friction between the air bag (200) and the cloth (300), are consistent. Figure 10 shows the condition of the air bag (200) when almost fully deployed. The air bag continues to deploy, coming into contact with the front glass (50) of the vehicle. The intervening cloth remains between the air bag (200) and the front glass (50). Thus, the air bag (200) proceeds to deploy smoothly, while receiving constant friction. Figure 11 shows another example of the invention. In this example, the hinges of the door (130) for the air bag unit (100) are arranged at the lower side of the unit. The intervening cloth (300) is also installed at the lower side of the air bag (200) intervening the door (130) in order to facilitate smooth deployment of the air bag. Figure 12 shows another example in which the intervening cloth (300) is arranged at the upper and lower sides of the air bag (200). The intervening cloth (300) is arranged in order to maintain a constant coefficient of friction between the air bag (200) and the surrounding interior elements, and thus does not cover the area of contact with the passenger (200A). Figure 13 shows another example with the intervening cloth (300) installed on both the left and right sides of the air bag (200). The intervening cloth (300) is sewed at the stitching positions (350) to the air bag (200). As described above, the air bag module of this invention is equipped with an intervening cloth located outside of the air bag which is being deployed by gas. Air bags usually generate friction when they come into contact with surrounding elements inside the car as they are being deployed. This device is structured so that the intervening cloth is sandwiched between surfaces coming into contact. Therefore, the air bag touches only the intervening cloth in stead of interior elements which have various coefficients of friction. The coefficient of friction between the air bag and the intervening cloth is constant, thus the air bag can be deployed smoothly into a set form and within a set time period. In addition, the inflated air bag can contract smoothly. Furthermore, this invention effectively protects the air bag because it eliminates any instances of it being caught and damaged by interior elements. Where technical features mentioned in any claim are followed by reference signs, those reference signs have been included for the sole purpose of increasing the intelligibility of the claims and accordingly, such reference signs do not have any limiting effect on the scope of each element identified by way of example by such reference signs.

Claims: An air bag device comprising an air bag (200) having an open end; a case (110) storing the folded airbag (200) and provided with a mounting part (112) securing an open end of said air bag (200) and a door (130) closing an open side thereof; and an intervening cloth (300), said intervening cloth (300) being installed outside said air bag (200) and near said mounting part (112) , characterized in that said intervening cloth (300) has a length permitting said intervening cloth (300) to extend beyond said door (130) and into the interior of a vehicle (10) as said air bag (200) deploys, such as to intervene between said air bag (200) and interior components of said vehicle (10), said intervening cloth (300) being sewed unto said air bag (200). The air bag device according to claim 1, characterized in that said case (110) is adapted to be inserted into an opening of a dash board (20) of said vehicle (10). The air bag device according to claims 1 or 2, characterized in that said door (130) has a predetermined width and height, said door (130) closing said case open side with said air bag (200) folded therein and being adapted to be opened upon inflation of said air bag (200) to permit said air bag (200) to deploy into the interior of said vehicle (10).

Inventors: IINUMA SHOJI, KIKUCHI RYO, YOSHIMURA TOSHIFUMI, IINUMA, SHOJI, KIKUCHI, RYO, YOSHIMURA, TOSHIFUMI
Applicants: ISUZU MOTORS LTD, ISUZU MOTORS LIMITED
Application year: 1995
Main classification: B60R21
IPC codes: B60R21