Airbag device

Abstract: The object is to provide an airbag device which is lightweight, in which alignment of an instrument panel and a lid is quite easy, and in which a lid does not lift from the instrument panel. The airbag device of the present invention comprises a retainer (1), an airbag (2) folded and accommodated in the retainer (1), a lid (3) for covering the opening of the retainer (1), and an inflator (4) for deploying the airbag (2). Belts (7) are arranged to extend along the outside of the retainer (1). The both ends of each belt (7) are connected to legs (6), respectively. The peripheral edge of the opening (11) of the instrument panel (10) is provided with a first stepped portion (10a), and a second stepped portion (10b). The rear surface of the peripheral edge of the lid (3) is laid on the first stepped portion (10a) and spacers (6L) are laid on the second stepped portion (10b). The belts (7) have elastic deformable portions (7b) so that the belts (7) are in elastic contact with the bottom of the retainer (1).

Description: [Industrial Field of the Invention] The present invention relates to an airbag device installed in a vehicle and, more particularly, to an airbag device suitably used as a passenger-side airbag device for protecting a front seat passenger in a vehicle. [Related Art] In a passenger-side airbag device, an airbag is accommodated within a canister-like retainer and the retainer is covered by a lid. The passenger-side airbag device is mounted to an instrument panel of a vehicle. In the event of a vehicle collision, an inflator spouts out gas, thereby inflating the airbag. The lid is opened toward the inside of a vehicle cabin due to pressing force by the airbag being inflated so as to allow the airbag to be inflated inside the vehicle cabin. There is an airbag device in which the lid is connected to the retainer by belts so that the lid can freely shift in directions crossing the instrument panel (in this specification, the directions will be referred to as "upward and downward directions"). DE 19 750 182 A, WO 9929539A and JP 07 117609A disclose an airbag device according to the preambles of independent claims 1 and 2. Fig. 8 is a sectional view showing the aforementioned conventional passenger-side airbag device in which an airbag 21 is arranged in the inside of a retainer 20 and an inflator 22 is disposed beneath the airbag 21. The top opening of the retainer 20 is covered by a lid 23. Arranged on both sides of the retainer 20 are hook fittings 24 of which hook portions 24a are inserted in holes 26 formed in legs 25 of the lid 23. The hook fittings 24 on the both sides of the retainer 20 are connected by belts 30. The belts 30 are fixed to the bottom of the retainer 20 by rivets 31. Engaging pieces 27 are formed on the outside of the legs 25. The periphery of a mounting opening 29 for an airbag device of the instrument panel 28 is engaged with the engaging pieces 27, whereby the lid 23 is fixed to an instrument panel 28. [Problems to be resolved by the Invention] In the conventional example shown in Fig. 8, since the belts 30 are fixed to the retainer 20 by the rivets 31, a reaction force from the belts 30 may be applied to the lid 23 fitted to the instrument panel 28. Therefore, stress may be constantly applied to the peripheral edge of the opening 29 of the instrument panel 28 and the periphery of the rid 23. Due to the upward pressing force of the belts 30, the lid 23 is pushed upward because of a clearance between the engaging pieces 27 and the opening 29 of the instrument panel 28 so that the lid 23 may be undesirably lifted slightly from the instrument panel 28. In the airbag device shown in Fig. 8, the movable range of the lid 23 is limited during installation of the airbag device to the instrument panel. It is an object of the present invention to solve the aforementioned problems and to provide an airbag device in which a lid is substantially not connected to a retainer..It is another object of the present invention to prevent the lid from lifting from the instrument panel. [Means to Solve the Problems] According to the present invention, this object is achieved by an airbag device as defined in claim 1 or claim 2. The dependent claim defines an advantageous and preferred embodiment of the present invention. An airbag device according to the present invention (claim 1) comprises: a canister-like retainer having an opening; an airbag which is accommodated in the retainer and of which a gas inlet is attached to the retainer; a lid for covering the opening of the retainer; and a fitting member for fitting the lid to an opening of an instrument panel, and is characterized in that both ends of each winding member which is arranged to extend along the outer surface of the retainer are connected to the lid; the winding member is elastic and at least a portion of the winding member is in elastic contact with the outer surface of the retainer whereby the lid is biased toward the retainer. A further airbag device according to the present invention (claim 2) comprises: a canister-like retainer having an opening; an airbag which is accommodated in the retainer and of which a gas inlet is attached to the retainer; an inflator for inflating the airbag; a lid for covering the opening of the retainer; and a fitting member for fitting the lid to an opening of an instrument panel, wherein both ends of the inflator outwardly project from the retainer, and is characterized in that both ends of each winding member which is arranged to extend along the outer surface of the inflator are connected to the lid; the winding member is elastic and at least a portion of the winding member is in elastic contact with the outer surface of the inflator whereby the lid is biased toward the retainer. In the airbag device having the structure mentioned above, the lid is pulled toward the retainer by the winding members, thereby preventing the lid from lifting from the instrument panel. Since the winding members are in elastic contact with the retainer (claim 1) or the inflator (claim 2), the winding members never hit nor rub the retainer, thus preventing noise generation. According to the present invention, the winding member may be directly connected to the lid or may be connected to the lid through attachments. In the latter case, it is preferable that the lid has legs projecting from the rear surface thereof to extend along the outer surface of the retainer, and attachments are attached to the legs and the winding members are connected to the attachments. This structure allows a tensile biasing force of the winding members to be transmitted to a wider area of the lid. [Brief Explanation of the drawings] Fig. 1 is a sectional view of an airbag device according to an embodiment of the invention. Fig. 2 is a front view of the airbag device shown in Fig 1. Fig. 3 is a sectional view of an airbag device according to another embodiment of the invention. Fig. 4 is a sectional view taken along a line IV-IV of Fig. 5. Fig. 5 is a front view showing an airbag device according to still another embodiment of the invention. Fig. 6 is a front view showing an airbag device according to further another embodiment of the invention. Fig. 7 is a perspective view showing a belt fixing member as an attachment. Fig. 8 is a sectional view showing a conventional example of an airbag device. Fig. 9 is a sectional view of a winding member used in an airbag device according to still another embodiment of the present invention. Fig. 10 is a sectional view of the airbag device to which the winding members shown in Fig. 9 are assembled. Fig. 11 is a perspective view of a fixing member for this airbag device. Fig. 12 is a sectional view showing the state of attaching the fixing member-shown in Fig. 11 to a leg of a lid. [Embodiments for carrying out the Invention] Hereinafter, embodiments of the present invention will be described with reference to the attached drawings. Fig. 1 is a sectional view of an airbag device according to an embodiment of the present invention, Fig. 2 is a front view of the airbag device. In this embodiment, the upward and downward directions mean directions crossing an instrument panel 10, that is, directions of arrows Z (upward and downward directions in Fig. 1), the forward and backward directions mean the forward and backward directions of a vehicle, that is, directions of arrows X, and the leftward and rightward directions mean the vehicle width directions, that is, directions of arrows Y. The airbag device comprises a retainer 1 having an opening formed in its top (front), an airbag 2 folded and accommodated in the retainer 1, a lid 3 made of synthetic resin for covering the opening of the retainer 1, an inflator (gas generator) 4 for deploying the airbag 2, and fittings 5 for mounting the airbag 2 to the retainer 1. In this embodiment, the retainer 1 is a canister which is long in the vehicle width direction and short in the vehicle longitudinal direction and has an opening formed in its top. The opening at its top is formed in a general rectangular shape. The lid 3 has legs 6 projecting from the rear surface thereof. The legs 6 are arranged to extend along the peripheral surfaces of an upper portion of the retainer 1 with a predetermined space between each leg 6 and each peripheral surface. The legs 6 have elasticity so that the legs 6 are deformable in the directions of arrows X. The legs 6 are inserted through an opening 11 of an instrument panel 10 from the upper side (from a vehicle cabin). The peripheral edge of the opening 11 is provided with a first stepped portion 10a, and a second stepped portion 10b extending from the first stepped portion 10a. The first stepped portion 10a is sank from the outer surface of the instrument panel 10 into the side behind the instrument panel 10 and the second stepped portion is further sank from the first stepped portion 10a. The lid 3 is provided with a plurality of L-like spacers 6L at the comers between the peripheral edge and the legs 6. Each spacer 6L comprises a vertical elongated portion along the outside surface of the leg 6 and a lateral elongated portion along the rear surface of the lid 3. The vertical elongated portions of the spacers 6L are inserted together with the legs 6 in the opening 11 and the lateral elongated portions of the spacers 6L are laid on the second stepped portion 10b so as to achieve alignment between the instrument panel and the lid. In this engaged state, the rear surface of the peripheral edge of the lid 3 is laid on the first stepped portion 10a. This mounting method can provide good appearance. Belts 7 as winding members are arranged to extend around the outside of the retainer 1. The both ends of each belt 7 are connected to the legs 6, 6, respectively. That is, the legs 6 are formed with holes 6a through which end portions of the belts 7 are inserted. Each end portion of the belts 7, after having been inserted through the hole 6a, is superposed on a portion of the respective belt 7 and is fastened by a rivet 8. Each of the belts 7 used in this embodiment has two elastic deformable portions 7b. The elastic deformable portions 7b are positioned on both sides of the retainer 1. A portion of the belt 7 between the elastic deformable portions 7b and 7b is in elastic contact with a bottom portion of the retainer 1, whereby the lid 3 is pulled downward toward the retainer 1 and is thus pressed against the instrument panel 10. The belt 7 is composed of a knitted cord or band of synthetic resin yams, a metallic belt such as a steel belt having elasticity, a fiber reinforced synthetic resin belt, or a rubber belt having embedded steel cords. The belt 7 is not connected to the retainer 1 at all and just extends along the both sides and the bottom of the retainer 1. There are slight spaces between the side surfaces of the retainer and the belt 7. The slight spaces allow the lid 3 to shift in directions of arrows Z, X for alignment without being substantially obstructed by the retainer 1. There are a plurality of belts 7 (two belts shown in Fig. 2) spaced apart from each other in the vehicle width direction (direction of arrows Y). A bracket for mounting the retainer 1 to a body member of the vehicle (not shown) is disposed on.a portion between the belts 7. Disposed on the rear surface of the lid 3 in a direction perpendicular to the legs 6 are further legs which extend along edges of the retainer 1 in the direction of arrows X, but not illustrated. The airbag device having the aforementioned structure is installed in the instrument panel 10 by inserting the airbag device through the opening of the instrument panel 10 from above of the instrument panel 10, laying the lateral elongated portions of the spacers 6L onto the second stepped portion 10b, laying the rear surface of the peripheral edge of the lid 3 onto the first stepped portion 10a, and fixing the retainer 1 to the body member of the vehicle through the bracket. The lid 3 of the airbag device having the aforementioned structure is not restricted by the retainer at all so as to freely shift in the upward and downward directions, the forward and backward directions, and the rightward and leftward directions because the belts 7 are not fixed to the retainer 1. Therefore, even when there is slight locational error between the airbag device and the opening 11 of the instrument panel 10, the error can be absorbed during the assembly of the airbag device into the instrument panel 10, whereby the lid 3 can be fitted to the opening 11 in the proper attitude. In addition, for installation of the airbag device into the instrument panel, the movable range of the lid 3 is greater than that of the device shown in Fig. 8. The lid shown in Fig. 1 can be easily formed by injection molding because under cut portions are not necessarily formed at portions corresponding to the spacers 6L in a mold for forming the lid. In this embodiment, when the airbag device is installed in the instrument panel 10, the lid 3 is pressed against the instrument panel 10. Therefore, even when the lid 3 is pushed upward by the airbag 2, the lid 3 does not lift from the instrument panel 10. In addition, the belts 7 are prevented from hitting or rubbing the retainer 1 because the belts 7 never vibrate or swing, thereby preventing noise generation. It should be understood that, as the inflator 4 spouts out gas in the event of an emergency such as a vehicle collision, the airbag 2 is inflated with the gas and the .lid 3 is torn along tear lines 3a to open, thereby allowing the airbag 2 to be inflated toward the inside of the vehicle cabin. Fig. 3 is a sectional view of an airbag device according to another embodiment. In this embodiment, only one stepped portion is formed around the peripheral edge of the opening 11 of the instrument panel 10. In this embodiment, a lid 3' has projections 12 on the outer surface of each leg 6. Interposed between the projections 12 and the peripheral edge of the lid 3' is the peripheral edge of the opening 11 of the instrument panel 10. Each projection 12 is formed to have an inferior surface inclined in such a direction closer to the retainer 1 from the tip to the lowest position. According to this design, when the airbag device with the lid 3' is inserted through the opening 11 of the instrument panel 10 so as to be installed in the vehicle, the inferior surfaces of the projections 12 slide on the peripheral end face of the opening 11, whereby the projections 12 are smoothly passed the edge of the opening 11. There are slight spaces between the projections 12 and the edge of the opening 11 of the instrument panel 10. The airbag device is installed to the instrument panel 10 by inserting the airbag through the opening 11 of the instrument panel 10 from above of the instrument panel 10, sandwiching the peripheral edge of the opening 11 of the instrument panel by the edges of the lid 3' and the projections 12, and fixing the retainer 1 to the body member of the vehicle through the bracket. During the airbag device is inserted through the opening 11, the legs 6 are deformed toward the retainer 1. After the projections pass the opening 11, the legs 6 are elastically restored to the original shape, whereby the peripheral edge of the opening 11 is sandwiched between the projections 12 and the peripheral edge of the lid 3'. The other components of this embodiment are the same as those of the airbag device shown in Fig. 1 so that the same numerals indicate the corresponding parts. Figs. 4 and 5 are a sectional view and a front view showing an airbag device according to another embodiment, respectively. Fig. 4 is a sectional view taken along a line IV-IV of Fig. 5. Fig. 6 is a front view showing an airbag device according to further another embodiment, and Fig. 7 is a perspective view showing a belt fixing member as an attachment. The airbag device comprises a retainer 1A having an opening formed in its top (front), an airbag 2 folded and accommodated in the retainer 1A, a lid 3A for covering the opening of the retainer 1A, an inflator (gas generator) 4A for deploying the airbag 2, and fittings for mounting the airbag 2 to the retainer 1A. In this embodiment, the retainer 1 is a canister which is long in the vehicle width direction and short in the vehicle longitudinal direction and has an opening formed in its top. The opening at its top is formed in a general rectangular shape. The lower half of the retainer 1A is shorter in the vehicle width direction than the upper half of the retainer 1A so that the both ends of the substantially cylindrical inflator 4A project outwardly from the side surfaces of the retainer 1A. The lid 3A has legs 6A projecting from the rear surface thereof. The legs 6A are arranged to extend along the peripheral surfaces of the upper half of the retainer 1A with a predetermined space between each leg 6A and each peripheral surface. The lid 3A also has projecting clasps 3b having hook-like shape to be engaged with the instrument panel. Belts 7A are arranged to extend around the outer periphery of the inflator 4A. The both ends of the belts 7A are fixed to the belt fixing members 70 as the attachments fixed to the legs 6A, 6A by fasteners such as rivets 8 and bolts. As clearly shown in Fig. 7, the fixing member 70 comprises hooks 71 to be received by holes 6a of the leg 6A, tongues 72 extending downward, and rivet holes 73 formed in the tongues 72. The number of the hooks 71 to be received by one leg 6A is greater than the number of the belts 7A. The belts 7A are fastened to the tongues 72 by rivets 8. The belts 7A are not connected to the retainer 1A and the inflator 4A at all and just extends along the both sides and the bottom of the inflator 4A. The belts 7A are in close contact with the inflator 4A. There is a slight space between the rear surface of the lid 3A and the top of the retainer 1A. This slight space is enough to shift for positioning without being obstructed by the retainer 1A. The other components and actions of the airbag device are the same as those of the aforementioned airbag device as shown in Fig. 1. Though the belts 7A receive the inflator 4A in Figs. 4 and 5, the belts 7A may receive the retainer as shown in Fig. 6. In the airbag device in Fig. 6, the length of the lower half of the retainer 1B in the vehicle width direction is longer than that of the retainer 1A of the airbag device shown in Fig. 5. The belts 7A are arranged to extend along the bottom of the retainer 1B. The other components of the airbag device shown in Fig. 6 are the same as those of the airbag device in Figs. 4 and 5 so that the same numerals indicate the corresponding parts. Since the belts 7A are not fixed to any of the retainer 1A, 1B and the inflator 4A, the lid 3A of the airbag device in Figs. 4 through 7 having the aforementioned structure can freely shift in the upward and downward directions, the forward and rearward directions, and the leftward and rightward directions without being restricted relative to the retainer 1A, 1B. Therefore, even when there is slight locational error between the airbag device and the opening 11 of the instrument panel 10, the error can be absorbed during the installation of the airbag device into the instrument panel 10, whereby the lid 3A can be fitted to the opening 11 in the proper attitude. In addition, for installation of the airbag device into the instrument panel 10, the movable range of the lid 3A is greater than that of the device shown in Fig. 8. Also in this embodiment, after installation of the airbag device into the instrument panel 10, the lid 3A is pressed against the instrument panel 10. Therefore, even when the lid 3A is pushed upward by the airbag 2, the lid 3A does not lift from the instrument panel 10. In addition, the belts 7A are prevented from hitting or rubbing the retainer 1A or 1B because the belts 7A never vibrate or swing, thereby preventing noise generation. Since the attachments 70 are provided, stress to be applied from the winding members 7A to the legs 6A can be widely dispersed. Therefore, the lid 3A is entirely uniformly biased to the retainer 1A or 1B. In the lid 3A of the airbag device according to the embodiments shown in Figs. 4 through 7, the projecting clasps 3b may have simply a rod-like shape, not a hook-like shape, thereby further facilitating the molding of the lid 3A by injection molding or the like. In this case, the rod-like projecting clasps 3b may be each provided with a rib to be laid on a step formed in the instrument panel, just like the spacer of the embodiment of Figs. 1-2, thereby increasing the rigidity of lid. Fig. 9 is a sectional view of a belt 7B as the winding member used in the airbag device according to another embodiment of the present invention, Fig. 10 is a sectional view of the airbag device to which the belts 7B are assembled, Fig. 11 is a perspective view of a fixing member 70A for this airbag device, and Fig. 12 is a sectional view showing the state of attaching the fixing member 70A to the leg 6B of the lid. In this embodiment, as shown in Fig. 10, the belt 7B has a convexly curved portion 80 which is formed by convexly curving a middle portion of the belt 7B. The belt 7B is elastically curved upward as a whole and arranged along the bottom of the inflator 4A. The both ends of the belt 7B are fixed to the fixing members 70A as attachments attached to the legs 6B, 6B of the lid 3B so that the top of the convexly curved portion 80 is in elastic contact with the inflator 4A. As shown in Fig. 11, the fixing member 70A comprises hooks 84 to be received by holes 82 of the leg 6B, dowel-like projections 88 to be fitted in the pin holes 86 of the leg 6B, tongues 90 extending downward, and rivet holes 92 formed in the tongues 90. The belts 7B are fixed to the tongues 90 by rivets 8. In the fixing member 70A, just like the fixing member 70 shown in Figs. 4 and 5, the number of the hooks 84 to be received by one leg 6B is greater than the number of the belts 7B. The structure of the lid 3B is the same as that of the lid 3A shown in Figs. 4, 5 except that the legs 6B each provided with the holes 82 and the pin holes 86 are employed instead of the legs 6A. The structure of the airbag device comprising the belts 7B, the fixing members 70A, and the lid 3B is the same as that of the airbag device shown in Figs. 4, 5, except that the belt 7A is replaced by the belt 7B, the fixing members 70 are replaced by the fixing members 70A, and the lid 3A is replaced by the lid 3B. The description of the other components of the airbag device is omitted since the same or corresponding components in Figs. 9 through 12 are marked by the same numerals used in Figs. 4, 5. In the airbag device shown in Figs. 9 through 12 having the structure mentioned above, the tops of the convexly curved portions 80 can shift in a relatively wide range from the upper-most position to the lower-most position or from the lower-most position to the upper-most position, according to the deformation of the belts 7B. Therefore, in the state that the airbag device is installed in the instrument panel (not shown), even when the retainer 1A and the lid 3B are in such a positional relation that these are too close to each other due to their locational error, or even when the retainer 1A and the lid 3B are in such a positional relation that these are too spaced or apart from each other, the tops of the convexly curved portions 80 can be kept in elastic contact with the inflator 4A, whereby the belts 7B constantly exert the biasing force to the lid 3B toward the retainer 1A. It should be understood that since the belts 7B are not fixed to any of the retainer 1A and the inflator 4A, the lid 3B of the airbag device can freely shift in the upward and downward directions, the forward and rearward directions, and the leftward and rightward directions without being restricted relative to the retainer 1A. Also in this embodiment, after installation of the airbag device into the instrument panel 10, the lid 3B is pressed against the instrument panel. Therefore, even when the lid 3B is pushed upward by the airbag 2, the lid 3A does not lift from the instrument panel. In addition, the belts 7B are prevented from hitting or rubbing the retainer 1A because the belts 7B never vibrate or swing, thereby preventing noise generation. In this embodiment, since the fixing members 70A are provided, stress to be applied from the belts 7B to the legs 6B can be widely dispersed, in the same manner as the airbag device shown in Figs. 4, 5. Therefore, the lid 3B is entirely uniformly biased to the retainer 1A. In addition, the dowel-like projections 88 are fitted in the aforementioned pin holes 86 when the hooks 84 are received by the aforementioned holes 82, whereby the fixing members 70A are not allowed to move relative to the side surfaces of the legs 6B. Therefore, the hooks 84 can be securely prevented from coming off the holes 82 due to vibration and the like. Also in the lid 3B of the airbag device according to the embodiment shown in Figs. 9 through 12, the projecting clasps 3b may have simply a rod-like shape, not a hook-like shape. In this case, the rod-like projecting clasps 3b may be each provided with a rib to be laid on a step formed in the instrument panel, just like the spacer of the embodiment of Figs. 1-2. This structure can facilitate the molding of the lid 3B by injection molding or the like and, because of the ribs, can increase the rigidity of lid. [Effects of the Invention] As described above, in the airbag device of the present invention, the lid can freely shift in the upward and downward directions, the forward and backward directions, and the rightward and leftward directions and has a greater shifting range, thereby significantly facilitating the alignment of the lid and the opening of the instrument panel for installation of the airbag device. The airbag device is installed without conventional hook fitting and can be made lightweight. In the airbag device, the lid does not lift from the instrument panel and the winding members never collide with the retainer, thus preventing noise generation.

Claims: An airbag device comprising: a canister-like retainer (1, 1B) having an opening; an airbag (2) which is accommodated in said retainer (1, 1B) and of which a gas inlet is attached to said retainer (1, 1B); a lid (3, 3', 3A) for covering the opening of said retainer (1, 1B); and a fitting member (6L) for fitting said lid (3, 3', 3A) to an opening (11) of an instrument panel (10), wherein both ends of each winding member (7, 7A) which is arranged to extend along the outer surface of said retainer (1, 1B) are connected to said lid (3, 3', 3A); and, said airbag device being characterized in that said winding member (7, 7A) is elastic and at least a portion of said winding member is in elastic contact with the outer surface of said retainer (1, 1B) whereby the lid (3, 3', 3A) is biased toward the retainer. An airbag device comprising: a canister-like retainer (1A) having an opening; an airbag (2) which is accommodated in said retainer (1A) and of which a gas inlet is attached to said retainer (1A); an inflator (4A) for inflating said airbag (2); a lid (3A, 3B) for covering the opening of said retainer (1A); and a fitting member (3b) for fitting said lid (3A, 3B) to an opening (11) of an instrument panel (10), wherein both ends of each winding member (7A, 7B) which is arranged to extend along the outer surface of said inflator (4A) are connected to said lid (3A, 3B), said airbag device being characterized in that both ends of said inflator (4A) outwardly project from said retainer (1A); and that said winding member (7A, 7B) is elastic and at least a portion of said winding member (7A, 7B) is in elastic contact with the outer surface of said inflator (4A) whereby the lid (3A, 3B) is biased toward the retainer (1A). An airbag device as claimed in claim 1 or 2, being characterized in that said lid (3A, 3B) has legs (6A, 6B) projecting from the rear surface thereof to extend along the outer surface of said retainer (1A, 1B), and that attachments (70, 70A) are attached to said legs (6A, 6B) and said winding members (7A, 7B) are connected to said attachments (70, 70A).

Inventors: IGAWA TADAHIRO, UCHIYAMA ATSUYUKI, IGAWA, TADAHIRO, UCHIYAMA, ATSUYUKI
Applicants: TAKATA CORP, TAKATA CORPORATION
Application year: 2001
Main classification: B60R21
IPC codes: B60R21