JP2005199987A - Airbag device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reliably open an air vent vent hole at the end of deployment and to easily control the opening timing of the vent hole.
SOLUTION: One end of a vent hole cover 40 is fixed in the vicinity of the center portion of a second base cloth 37, and the other end is connected to a joint portion 39 of the first and second base cloths 36, 37 in the vicinity of the outer peripheral portion of the airbag 32. Since the joints 39 are separated at the end of deployment of the airbag 32, the other end of the vent hole cover 40 can be separated from the first and second base fabrics 36, 37 by opening the vent hole 37b. As a result, the vent hole 37b is kept closed until the deployment of the airbag 32 is almost completed to promote the increase of the internal pressure, and after the deployment of the airbag 32 is completed, the gas is discharged from the vent hole 37b and the internal pressure is excessive. Increase can be suppressed. In addition, by adjusting the position where the other end of the vent hole cover 40 is joined to the joining portion 39, the timing at which the vent hole 37b is opened can be easily controlled.
[Selection] Figure 7

Description

  The present invention relates to an airbag apparatus in which a vent hole is formed in a base fabric constituting an airbag and the vent hole is opened in a process in which the airbag is deployed with a gas generated by an inflator when a vehicle collides.

  An airbag that restrains an occupant by deploying in a vehicle interior with gas supplied from an inflator at the time of a vehicle collision includes a vent hole for preventing the internal pressure from rising excessively. If this vent hole is opened from the initial stage of airbag deployment, the gas supplied from the inflator leaks from the vent hole and the rise of the internal pressure of the airbag is delayed, so the vent hole is opened while the airbag is deployed. An air bag device that performs such a process is known from Japanese Patent Application Laid-Open No. 2004-228561.

The conventional airbag apparatus includes a strap that connects the inner surfaces of the airbag in order to regulate the final deployment shape of the airbag, and an intermediate portion of the strap is sewn around a vent hole so that the vent When the hole is closed and tension is applied to the strap in the process of deploying the airbag and the sewing part is broken, the vent hole is opened and gas is discharged.
Japanese Patent Laid-Open No. 6-107099

  By the way, in the above-mentioned conventional one, there is a possibility that the sewing portion of the strap breaks before the airbag is fully deployed and the vent hole opens, and it is difficult to adjust the timing when the vent hole opens. There was a problem.

  The present invention has been made in view of the circumstances described above, and it is an object of the present invention to reliably open the vent hole of an airbag at the end of deployment and easily control the timing of opening the vent hole.

  In order to achieve the above object, according to the first aspect of the present invention, a process of forming a vent hole in a base fabric constituting an airbag and deploying the airbag with a gas generated by an inflator at the time of a vehicle collision In the airbag device that opens the vent hole at the vent, the overlapped base fabric is joined at a separable joint, and the joint is separated by a load when the airbag is deployed, and the vent hole closes the vent hole An air bag characterized in that an end portion of a cover is joined to the joint portion in the vicinity of an outer peripheral portion of the airbag, and the vent hole is opened by separating the end portion of the vent hole cover from a base cloth by separating the joint portion. A device is proposed.

  According to the invention described in claim 2, in addition to the configuration of claim 1, an airbag apparatus characterized in that the vent hole cover is joined to a base cloth at a part of the periphery of the vent hole. Proposed.

  According to the invention described in claim 3, the vent hole is formed in the base fabric constituting the airbag, and the vent hole is opened in the process of deploying the airbag with the gas generated by the inflator at the time of the collision of the vehicle. In the bag device, the overlapped base fabric is joined at a separable joint, the joint is separated by a load when the airbag is deployed, one end communicates with the vent hole, and the other end of the airbag A duct that is joined and closed to the joint portion in the vicinity of the outer peripheral portion is provided along the inner surface of the base fabric, and the vent hole is opened by releasing the other end of the duct by separating the joint portion. An airbag device is proposed.

  According to the invention described in claim 4, the vent hole is formed in the base cloth constituting the airbag, and the vent hole is opened in the process of deploying the airbag with the gas generated by the inflator at the time of the collision of the vehicle. In the bag device, the overlapped base fabric is joined at a separable joint, the joint is separated by a load when the airbag is deployed, one end communicates with the vent hole, and the other end of the airbag An air bag characterized in that a duct that is joined and closed to the joint near the outer periphery is provided outside the airbag, and the vent hole is opened by releasing the other end of the duct by separating the joint. A device is proposed.

  According to the invention described in claim 5, in addition to the configuration of any one of claims 1 to 4, the joint portion extends from the center portion of the first and second base fabrics to the outer peripheral portion. An airbag device is proposed which extends in a spiral shape.

  According to the invention described in claim 6, in addition to the configuration of claim 5, the spiral joint has a non-joint part in which joining is interrupted at least at one place. An airbag device is proposed in which the portion is disposed at a position shifted in the circumferential direction with respect to the radially inner end of the joint portion.

  According to the seventh aspect of the present invention, in addition to the configuration of any one of the first to sixth aspects, the radially inner end of the joined portion, or the joined portion is connected to the non-joined portion. An airbag device is proposed in which the continuous end portions are directed to the central portion of the airbag.

  According to the invention described in claim 8, in addition to the structure of any one of claims 1 to 7, the vent hole formed in at least one of the first and second base fabrics functions. Therefore, there is proposed an airbag device characterized by having a gas discharge portion that opens and discharges gas when the internal pressure of the airbag becomes equal to or higher than a predetermined value.

  The first and second base fabrics 36 and 37 of the embodiment correspond to the base fabric of the present invention, the sewing portion 39 of the embodiment corresponds to the joint portion of the present invention, and the non-sewn portions 39a and 39b of the embodiment. Corresponds to the non-joined portion of the present invention, and the weakened portions 38a and 53 of the embodiment correspond to the gas discharge portion of the present invention.

  According to the configuration of the first aspect, since the overlapped base fabrics are joined at the separable joining portion, the inside pressure of the airbag is changed by sequentially separating the joining portions with a load when the airbag is deployed. It is possible to restrain the occupant softly by appropriately controlling the vehicle. Since the end of the vent hole cover is joined to the joint near the outer periphery of the airbag, the vent hole cover is separated from the base fabric by separating the joint at the end of the airbag deployment. As a result, the vent hole is kept closed until the airbag deployment is almost completed to promote the increase of the internal pressure, and after the airbag deployment is completed, the gas is discharged from the vent hole. An excessive increase in internal pressure can be suppressed. And the timing which a vent hole opens can be easily controlled by adjusting the position which joins the edge part of a vent hole cover to a junction part.

  According to the configuration of the second aspect, since the vent hole cover is joined to the base cloth at a part around the vent hole, the direction of the gas discharged from the vent hole can be regulated by the vent hole cover.

  According to the configuration of the third aspect, since the overlapped base fabrics are joined at the separable joining portion, the inside pressure of the airbag is changed by sequentially separating the joining portions with a load when the airbag is deployed. It is possible to restrain the occupant softly by appropriately controlling the vehicle. In addition, since the duct is provided along the inner surface of the base fabric with one end communicating with the vent hole and the other end joined to the joint portion, the vent hole cover is separated by separation of the joint portion at the end of the airbag deployment. The vent hole can be opened by releasing the blockage at the other end. This keeps the vent hole closed until the airbag deployment is almost completed, thereby increasing the internal pressure and completing the airbag deployment. After that, gas can be discharged from the vent hole to suppress an excessive increase in internal pressure. Moreover, by adjusting the position where the other end of the vent hole cover is joined to the joint, it is possible not only to easily control the timing at which the vent hole opens, but also to reduce the amount of gas discharged by changing the diameter of the duct. Can be controlled.

  According to the configuration of the fourth aspect, since the overlapped base fabrics are joined at the separable joint, the inner pressure of the airbag is changed by sequentially separating the joint with a load when the airbag is deployed. It is possible to restrain the occupant softly by appropriately controlling the vehicle. In addition, since the duct is provided outside the airbag with one end communicating with the vent hole and the other end joined to the joint portion, the other end of the vent hole cover is separated by separation of the joint portion at the end of the airbag deployment. The vent hole can be released by releasing the blockage of the air bag, thereby maintaining the vent hole in a closed state until the deployment of the airbag is almost completed and promoting an increase in the internal pressure. Excessive rise in internal pressure can be suppressed by discharging gas from the vent hole. Moreover, by adjusting the position where the other end of the vent hole cover is joined to the joint, it is possible not only to easily control the timing at which the vent hole opens, but also to reduce the amount of gas discharged by changing the diameter of the duct. Further, the exhaust gas can be prevented from hitting the occupant by providing the duct in a direction away from the occupant. Further, by providing a duct outside the airbag, the length of the duct can be freely set and the gas discharge amount and discharge time can be controlled more appropriately.

  According to the structure of Claim 5, since a junction part is spirally extended toward the outer peripheral part from the center part of the 1st, 2nd base fabric, the said junction part is centered with the load at the time of an airbag expansion | swelling. By separating sequentially from the outer part to the outer peripheral part, it is possible to prevent the airbag from being expanded in the front-rear direction at the initial stage of deployment, and by gradually increasing the volume of the airbag to appropriately control the change in internal pressure, In addition to being able to be restrained softly, when the separation of the joint portion is completed, the airbag can be deployed in a final shape that is flat in the front-rear direction to exhibit a sufficient restraining force. In addition, a large stress can be concentrated on the end of the joint to ensure separation, and the separation direction of the joint does not change abruptly, enabling smooth separation of the joint and enabling the internal pressure and deployment of the airbag. The speed can be easily controlled.

  According to the configuration of the sixth aspect, since the non-joining portion where the joining is interrupted is provided in at least one of the spiral joining portions, even if a part of the joining portion is pressed down and the separation is stopped there, the joining The airbag can be deployed without hindrance by newly starting separation from the end where the portion continues to the non-joined portion. Moreover, since the non-joined portion is disposed at a position shifted in the circumferential direction with respect to the radially inner end of the joined portion, the probability that both the radially inner end of the joined portion and the non-joined portion are simultaneously pressed down is reduced. The airbag can be deployed more reliably.

  According to the configuration of the seventh aspect, since the radially inner end of the joined portion or the end portion where the joined portion continues to the non-joined portion is directed to the central portion of the airbag, an inflator provided in the central portion of the airbag is generated The load due to the pressure of the gas to be performed can be effectively separated at the inner end in the radial direction of the joint portion or the end portion where the joint portion continues to the non-joint portion and can be reliably separated.

  According to the configuration of claim 8, when the vent hole formed in at least one of the first and second base fabrics does not function for some reason and the internal pressure of the airbag becomes a predetermined value or more, the gas discharge portion is caused by the internal pressure. Since the gas inside the airbag is discharged after being opened, it is possible to prevent the internal pressure of the airbag from excessively increasing by causing the gas exhaust portion to function as a vent hole.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below based on examples of the present invention shown in the accompanying drawings.

  1 to 7 show a first embodiment of the present invention. FIG. 1 is a perspective view of a front part of a passenger compartment of an automobile, FIG. 2 is an enlarged sectional view taken along line 2-2 of FIG. 1, and FIG. 4 is a front view of the airbag, FIG. 5 is a rear view of the airbag, FIG. 6 is an enlarged sectional view taken along line 6-6 of FIG. 5, and FIG. is there.

  As shown in FIG. 1, a driver seat airbag module 13 is housed in a steering wheel 12 disposed in front of the driver seat 11.

  As shown in FIG. 2, the steering wheel 12 includes a boss portion 16 fixed to the rear end of the steering shaft 14 with a nut 15, a front cover 17 fixed to the boss portion 16, and a bolt 18 on the rear surface of the front cover 17. .., A plurality of spoke portions 20 extending radially from the front cover 17, and a steering wheel main body portion 21 connected to the outer periphery of the spoke portions 20. A retainer 22 is fastened to the inner peripheral surface of the rear cover 19 with bolts 18, and the airbag module 13 is supported by the retainer 22. On the inner surface of the rear cover 19, a thin tear line 19a that is broken when the airbag 32 is inflated is formed.

  The airbag module 13 includes an inflator 31 filled with a propellant that generates high-pressure gas by combustion, an airbag 32 configured by sewing a base fabric, and a fixing ring 33 that fixes a base portion of the airbag 32. The flange 31a of the inflator 31 and the fixing ring 33 are overlapped on the front surface and the rear surface of the retainer 22, and are fastened by bolts 34 and nuts 35. At this time, the base portion of the airbag 32 is sandwiched and fixed between the rear surface of the retainer 22 and the front surface of the fixing ring 33.

  As shown in FIG. 3, the circular airbag 32 includes a first base fabric 36 on the rear side (side facing the occupant) and a second base fabric 37 on the front side superimposed on the front surface thereof, The second base fabrics 36 and 37 are sewn together at an outer peripheral sewing portion 38. The second base cloth 37 of the airbag 32 is penetrated by a circular opening 37a surrounding the inflator 31, two vent holes 37b and 37b through which a part of gas escapes when the airbag 32 is inflated, and bolts 34. A number of bolt holes 37c are formed. The airbag 32 further includes a vent hole cover 40 made of the same material as the first and second base fabrics 36 and 37. The vent hole cover 40 includes an annular mounting portion 40a and two belt-like portions 40b and 40b extending in a direction away from each other. The mounting portion 40a has a circular opening 40c and bolts 34. Four bolt holes 40d ... penetrating therethrough are formed.

  4 to 6, the attachment portion 40a of the airbag cover 40 is superimposed on the outer surface of the center portion of the second base fabric 37, and is sewn integrally with the two sewing portions 41, 41. The two belt-like portions 40 b and 40 b of the airbag cover 40 are inserted into the two vent holes 37 b and 37 b of the second base fabric 37 from the outer surface side to the inner surface side. At this time, since the diameters of the vent holes 37b and 37b are the same as the widths of the strip portions 40b and 40b, the vent holes 37b and 37b are closed by the strip portions 40b and 40b. The overlapped second base fabric 37 and the mounting portion 40a of the vent hole cover 40 are sandwiched between the rear surface of the retainer 22 and the front surface of the fixing ring 33, and are fastened together with bolts 34. The gas generated by the inflator 31 is supplied into the airbag 32 from the central opening 37 a of the second base fabric 37 and the opening 40 c of the vent hole cover 40.

  The overlapped first and second base fabrics 36 and 37 are sewn by three concentric sewing portions 39 at positions close to the outer periphery. The outer peripheral sewing portion 38 is firmly sewn with a thick thread so as not to be broken when the airbag 32 is inflated, but the three concentric sewing portions 39 inside thereof are broken when the airbag 32 is inflated. It is fragilely sewn with a thin thread to obtain. At this time, the tips of the two belt-like portions 40b, 40b extending inside the airbag 32 are simultaneously sewn by the three sewing portions 39.

  Therefore, when acceleration of a predetermined value or more is detected at the time of a vehicle collision, the inflator 31 is ignited, and the folded airbag 32 starts to be inflated with the gas generated by the inflator 31. The rear cover 19 that has received pressure to inflate the airbag 32 breaks the tear line 19a, and the airbag 32 is deployed into the passenger compartment through an opening formed therein.

  As shown in FIG. 7 (A), when the airbag 32 is inflated, the three sewing portions 39... Integrally join the first and second base fabrics 36 and 37. The occupant can be restrained softly by preventing inflating. As the internal pressure of the airbag 32 increases, the three sewn portions 39... Sequentially break from the radially inner side to the outer side, so that the airbag 32 gradually increases in volume while maintaining an appropriate internal pressure. Finally, it can be developed into a flat shape in the front-rear direction to exhibit the maximum restraining force.

  Since the other ends of the belt-like portions 40b, 40b of the vent hole cover 40 are restrained by the first and second base fabrics 36, 37 until the three sewing portions 39 are all broken, the vent holes 37b, 37b is blocked by the belt-like portions 40b and 40b to prevent gas leakage, so that the internal pressure of the airbag 32 can be quickly raised and the internal pressure can be appropriately maintained. When the three sewing parts 39 are all broken at the end of deployment of the airbag 32, as shown in FIG. 7B, the other ends of the belt-like parts 40b and 40b of the vent hole cover 40 are released. The vent holes 37b and 37b are opened by part of the belt-like portions 40b and 40b being pushed out of the vent holes 37b and 37b. As a result, excess gas can be discharged from the vent holes 37b and 37b to prevent an excessive increase in the internal pressure of the airbag 32.

  In this embodiment, the tips of the belt-like portions 40b, 40b of the vent hole cover 40 are sewn to all three sewing portions 39, but the inner two sewing portions 39, 39 or the innermost one. The timing at which the vent holes 37b and 37b are opened can be arbitrarily adjusted by sewing on the sewing portion 39. Further, since the belt-like portions 40b and 40b are arranged so as to pass through the vent holes 37b and 37b, the belt-like portions 40b and 40b are prevented from being displaced with respect to the vent holes 37b and 37b to cause gas leakage. Can do.

  Next, second and third embodiments of the present invention will be described with reference to FIGS.

  In the first embodiment, the attachment portion 40a of the vent hole cover 40 is disposed on the outer surface of the second base cloth 37, and the belt-like portions 40b and 40b pass through the vent holes 37b and 37b and enter the inner surface of the second base cloth 37. However, the vent hole cover 40 of the second embodiment shown in FIG. 8 is disposed so as to be entirely along the inner surface of the second base fabric 37. At this time, the strips 40b and 40b are allowed to slide in the longitudinal direction on the inner surface of the second base cloth 37 so that the strips 40b and 40b of the vent hole cover 40 are not displaced with respect to the vent holes 37b and 37b. The guide member 42 is fixed by the sewing parts 43 and 43.

  Further, the vent hole cover 40 of the third embodiment shown in FIG. 9 is disposed so as to be entirely along the outer surface of the second base cloth 37, and the belt-like portions 40b and 40b are not displaced with respect to the vent holes 37b and 37b. In this manner, the guide member 42 that allows the belt-like portions 40 b and 40 b to slide in the longitudinal direction is fixed to the outer surface of the second base fabric 37 by the sewing portions 43 and 43.

  Thus, the second and third embodiments can achieve the same effects as those of the first embodiment described above.

  Next, a fourth embodiment of the present invention will be described with reference to FIG.

  In the first to third embodiments, the attachment portion 40 a of the vent hole cover 40 is fixed to the center portion of the second base cloth 37, and the tips of the belt-like portions 40 b and 40 b are fixed to the outer peripheral portion of the second base cloth 37. However, in the fourth embodiment, the two vent hole covers 40, 40, which are formed in a band shape as a whole, are arranged in parallel so as to sandwich both sides of the opening 37a on the outer surface of the second base fabric 37. Each vent hole cover 40 slidably penetrates two guide members 42 and 42 fixed to the second base cloth 37 by sewing portions 43 so as to cover the vent hole 37b of the second base cloth 37. The second base fabric 37 is sewn by three concentric sewing portions 39 that can be broken at both ends.

  Thus, the fourth embodiment can achieve the same effects as those of the first embodiment described above. The vent hole covers 40, 40 may be disposed on the inner surface of the second base fabric 37, or may be disposed through the vent holes 37b, 37b so that one end side is disposed on the outer surface and the other end side is disposed on the inner surface.

  Next, a fifth embodiment of the present invention will be described with reference to FIGS.

  The fifth embodiment includes a duct component member 44 fixed to the inner surface of the second base fabric 37. The duct component member 44 includes an annular mounting portion 44a and two duct portions 44b and 44b extending in directions away from each other. The mounting portion 44a has a circular opening 44c and bolts 34. Four bolt holes 44d through are formed. The attachment portion 44a is superimposed on the inner surface of the center portion of the second base fabric 37 and integrally sewn with two sewing portions 45, 45, and the duct portions 44b, 44b are secondly formed with U-shaped sewing portions 46, 46. It is sewn on the inner surface of the base fabric 37. Thereby, cylindrical ducts 47 and 47 are formed between the duct portions 44b and 44b and the second base cloth 37, and the radially inner ends thereof communicate with the vent holes 37b and 37b, and the vicinity of the radially outer end is 3. The sewing parts 39 are sewn to prevent the airbag 32 from communicating with the internal space.

  Therefore, the vent holes 37b and 37b do not function at the initial and middle stages of the deployment of the airbag 32, because the ducts 47 and 47 are closed by the sewing sections 39, and the sewing sections 39 and so on at the end of the deployment of the airbag 32. When the air bag 32 is broken, the internal space of the airbag 32 communicates with the vent holes 37b and 37b through the ducts 47 and 47, thereby discharging excess gas and preventing an excessive increase in the internal pressure of the airbag 32. it can.

  According to the fifth embodiment, in addition to the effects of the first to fourth embodiments described above, the amount of gas discharged from the vent holes 37b and 37b can be adjusted by adjusting the diameters of the ducts 47 and 47. The further effect can be achieved.

  Next, a sixth embodiment of the present invention will be described with reference to FIGS.

  The fifth embodiment described above includes two ducts 47, 47 inside the airbag 32, but the sixth embodiment includes three ducts 48 ... outside the airbag 32. That is, three vent holes 37b... Are formed on the outer peripheral portion of the second base cloth 37 of the airbag 32, and the same as the first and second base cloths 36, 37 around these vent holes 37b. The base ends of the cylindrical duct constituent members 49 made of a material are sewn at the sewing portions 50.

  The three severable sewn portions 39... For integrating the first and second base fabrics 36, 37 extend spirally from the radially inner side to the radially outer side, and the folded duct constituent member 49. The tip is sewn integrally with the breakable sewing portion 39. The point a at the radially inner end of the sewing portion 39... Is oriented toward the center of the airbag 32. When the airbag 32 is deployed, stress is concentrated on the point a to accelerate the start of breakage of the sewing portion 39. doing.

  Therefore, at the initial and middle stages of deployment of the airbag 32, the ducts 48 are closed by the sewing portions 39, so the vent hole 37b does not function, and the sewing portions 39 break at the end of the deployment of the airbag 32. Then, the internal space of the airbag 32 communicates with the atmosphere via the vent holes 37b and the ducts 48, so that excess gas can be discharged and an excessive increase in the internal pressure of the airbag 32 can be prevented.

  According to the sixth embodiment, in addition to the effects of the first to fourth embodiments described above, the amount of gas discharged from the vent holes 37b can be adjusted by adjusting the diameter of the ducts 48, and so on. By directing the duct component members 49 to the front side of the vehicle body, that is, the side opposite to the passenger, it is possible to achieve a further effect that the gas discharged from the vent hole 37b does not hit the passenger. Further, by providing the ducts 48 outside the air bag 32, the length of the ducts 48 can be freely set to control the gas discharge amount and discharge time more appropriately. Can be achieved.

  In addition, the first and second base fabrics 36 and 37 of the airbag 32 are sewn by the spiral sewing portions 39... And the spiral sewing portions 39. By breaking, the occupant can be effectively restrained by arbitrarily controlling the internal pressure, the deployment speed, the shape and the like in the deployment process of the airbag 32. In particular, the spiral sewing parts 39 have substantially the same curvature and there is no portion where the curvature changes abruptly, so that not only the breakage is performed smoothly, but also the internal pressure and deployment during the deployment process of the airbag 32 Control of speed, shape, etc. becomes easier.

  In the above-described sixth embodiment, when the inflator 31 is ignited in two stages, the strength of the sewing portions 39 is weakened between the points a and b on the radially inner side, and the points b on the radially outer side and It is strengthened between points c, and the first stage ignition of the inflator 31 breaks the points a and b of the sewing portions 39... on the front side of the vent hole 37b. The internal pressure of the airbag 32 can be controlled with higher accuracy by breaking between the points b and c of the sewing parts 39 including the vent holes 37b.

  For example, even if there is an error in the time at which the points a and b of the sewing portion 39 break due to the first stage ignition of the inflator 31, the second stage of the inflator 31 is ignited at a timing to compensate for the error. By breaking between the points b and c of the sewing portions 39, it is possible to eliminate an error in the timing of opening the vent holes 37b. Of course, the inflator 31 may ignite in three or more stages.

  Next, a seventh embodiment of the present invention will be described with reference to FIGS.

  The seventh embodiment includes three sewing portions 39 for sewing the overlapped first and second base fabrics 36, 37 in a spiral shape, and one vent hole provided in the second base fabric 37. Both end portions of the vent hole cover 40 that closes the cover 37b are sewn together by three sewing portions 39. At this time, a portion located on the outer peripheral side of the airbag 32 in the vicinity of the vent hole 37 b is sewn integrally to the vent hole cover 40 by the sewing portion 51.

  Each of the sewing parts 39 has non-sewing parts 39a and 39b where sewing is interrupted at a plurality of places (two places in the embodiment), and the sewing parts 39 connected to the non-sewing parts 39a and 39b. The point “d” at the end of “...” points toward the center of the airbag 32. At least one of the two non-sewn portions 39a and 39b, in the embodiment, the circumferential position of the radially inner non-sewn portion 39a is relative to the point a at the radially inner end of the sewn portions 39. Are displaced in the circumferential direction.

  Therefore, when the airbag 32 is deployed, the non-breakable portion surrounded by the chain line is pressed against something, so that the break starting from the point a at the radial inner end of the spiral sewing portion 39 stops at the non-breakable portion. However, first, the rupture is newly started in the clockwise direction and the counterclockwise direction from the point d facing the two non-sewn parts 39a and 39b of the sewing parts 39, and finally, all the sewing parts 39 except the non-breakable parts. By breaking, ..., most of the airbag 32 can be deployed to exhibit occupant restraint performance. At this time, the point d facing the two non-sewn portions 39a and 39b of the sewing portion 39 is directed to the center of the airbag 32 in the same manner as the point a at the radially inner end of the sewing portion 39. The stress can be concentrated there and the fracture can be started reliably.

  The circumferential position of at least one of the non-sewn parts 39a, 39b (non-sewn part 39a in the embodiment) is circumferential with respect to the point a at the corresponding radial inner end of the sewn part 39. Therefore, it is possible to avoid the situation in which the points a and the plurality of points d are all included in the non-breakable portion and the sewing portions 39 are not broken.

  Further, when the restriction at both ends of the vent hole cover 40 is released and the vent hole 37b is opened, the outer peripheral side of the airbag 32 around the vent hole 37b is blocked by the vent hole cover 40 (FIG. 16B). Reference), excess gas discharged from the vent hole 37b can be deflected toward the center of the airbag 32.

  Next, an eighth embodiment of the present invention will be described with reference to FIG.

  In the seventh embodiment, one vent hole cover 40 is sewn by the sewing portion 51 on one side near the vent hole 37b, but in the eighth embodiment, two vent hole covers 40, 40 are overlapped. One vent hole cover 40 is sewn by a sewing part 51 on one side near the vent hole 37b, and the other vent hole cover 40 is sewn by a sewing part 52 on the other side near the vent hole 39b. It is.

  Thus, the two vent hole covers 40 and 40 cooperate to guide both sides of the vent hole 37b so as to discharge excess gas straight forward.

  Next, a ninth embodiment of the present invention will be described with reference to FIG.

  The ninth embodiment is a modification of the first embodiment shown in FIG. 5, and two vent holes 37 b and 37 b are formed in the second base cloth 37 of the first and second base cloths 36 and 37 overlapped with each other. Is formed, and a predetermined number (three in the embodiment) of fragile portions 38a... Are formed on the outer periphery of the first and second base fabrics 36 and 37. The fragile portions 38a are sewn with a thread that is thinner than the other portions of the sewing portion 38, and are easily broken accordingly.

  Thus, at the end of deployment of the airbag 32, when the two vent holes 37b and 37b remain blocked for some reason and cannot function, the internal pressure of the airbag 32 exceeds a predetermined value. The weak part 38a ... of the sewing part 38 is broken, and the opening formed therein functions as a vent hole to discharge gas, thereby preventing the internal pressure of the airbag 32 from being excessively increased.

  Next, a tenth embodiment of the present invention will be described with reference to FIG.

  The tenth embodiment is a modification of the ninth embodiment shown in FIG. 18. In the ninth embodiment, the fragile portions 38a are formed in the sewing portion 38, but the tenth embodiment has a second base fabric 37. A fragile portion 53 is formed by sewing so as to close the slit obtained by cutting the wire into a line. The breaking strength of the fragile portion 53 is set to be higher than the breaking strength of the sewing portions 39 and lower than the breaking strength of the sewing portion 38.

  Thus, at the end of deployment of the airbag 32, when the two vent holes 37b and 37b remain blocked for some reason and cannot function, the internal pressure of the airbag 32 exceeds a predetermined value. Since the fragile portion 53 is broken and the opening formed therein functions as a vent hole to discharge gas, it is possible to prevent the internal pressure of the airbag 32 from being excessively increased.

  The embodiments of the present invention have been described above, but various design changes can be made without departing from the scope of the present invention.

  For example, in the embodiment, the first and second base fabrics 36, 37 are sewn by the sewing portions 39, but separable adhesion or welding can be employed instead of the sewing.

  Further, the shape of the sewing portions 39 is not limited to an annular shape or a spiral shape, and may be any other shape such as a twisted shape.

  Further, the sewing strength (joint strength of the joint portion) of the sewing portion 39 is changed depending on the thickness of the sewing thread, the material of the sewing thread, the density of the stitches, the length of the sewing portion 39, the number of times of sewing by overlapping. Thus, the internal pressure of the airbag 32 can be controlled. In general, when the breaking strength of the sewing portions 39 is increased or the length of the sewing portions 39 is increased, the volume of the airbag 32 becomes difficult to increase, so that the internal pressure increases, and vice versa. Since the volume of 32 tends to increase, the internal pressure becomes low.

  Further, by combining a portion having a high breaking strength and a portion having a low breaking strength in one sewing portion 39, the internal pressure of the airbag 32 can be controlled more precisely. Specifically, if the breaking strength at the point a, which is the starting point of the sewing portion 39, is increased, the sewing portion 39 is less likely to break at the initial stage of deployment. Therefore, it is necessary to quickly raise the internal pressure of the airbag 32 at the initial stage of deployment. By securing the occupant restraining force and then breaking the sewing portion 39, the internal pressure of the airbag 32 can be kept substantially constant and optimal occupant restraining performance can be exhibited.

  Moreover, what combined each characteristic of 1st Example-10th Example mentioned above arbitrarily shall also be contained in the Example of this invention.

Perspective view of the front part of the car compartment 2-2 line enlarged sectional view of FIG. Exploded perspective view of airbag Front view of airbag Airbag rear view 6-6 enlarged sectional view of FIG. Action diagram when deploying airbag The figure corresponding to the said FIG. 5 based on 2nd Example. The figure corresponding to the said FIG. 5 based on 3rd Example. The figure corresponding to the said FIG. 5 based on 4th Example. The figure corresponding to the said FIG. 3 based on 5th Example. Action diagram when deploying airbag The figure corresponding to the said FIG. 3 based on 6th Example. Action diagram when deploying airbag The figure corresponding to the said FIG. 5 based on 7th Example. 16-16 expanded sectional view of FIG. The figure corresponding to the said FIG. 16 based on 8th Example. The figure corresponding to the said FIG. 5 based on 9th Example. The figure corresponding to the said FIG. 5 based on 10th Example.

Explanation of symbols

31 Inflator 32 Airbag 36 First Base Fabric (Base Fabric)
37 Second base fabric (base fabric)
37b Vent hole 38a Weak part 39 Sewing part (joint part)
39a Non-sewn part (non-joined part)
39b Non-sewing part (non-joining part)
40 Vent hole cover 47 Duct 48 Duct 53 Vulnerable part

Claims (8)

A vent hole (37b) is formed in the base fabric (36, 37) constituting the airbag (32), and the vent hole is developed in the process of deploying the airbag (32) with the gas generated by the inflator (31) when the vehicle collides. In the airbag device that opens (37b),
The overlapped base fabric (36, 37) is joined at a separable joint (39), and the joint (39) is separated by a load when the airbag (32) is deployed, and the vent hole (37b) The end of the vent hole cover (40) that closes the joint (39) is joined to the joint (39) in the vicinity of the outer periphery of the airbag (32), and the vent hole cover (40) is separated by separating the joint (39). An air bag apparatus characterized in that the vent hole (37b) is opened by separating the end from the base fabric (36, 37).   The airbag device according to claim 1, wherein the vent hole cover (40) is joined to a base fabric (36, 37) at a part of the periphery of the vent hole (37b). A vent hole (37b) is formed in the base fabric (36, 37) constituting the airbag (32), and the vent hole is developed in the process of deploying the airbag (32) with the gas generated by the inflator (31) when the vehicle collides. In the airbag device that opens (37b),
The overlapped base fabrics (36, 37) are joined by a separable joining part (39), the joining part (39) is separated by a load when the airbag (32) is deployed, and one end is a vent hole. A duct (47) that communicates with (37b) and is closed at the other end in the vicinity of the outer periphery of the airbag (32) by being joined to the joint (39) along the inner surface of the base fabric (36, 37). The airbag device is provided, wherein the vent hole (37b) is opened by unblocking the other end of the duct (47) by separating the joint portion (39). A vent hole (37b) is formed in the base fabric (36, 37) constituting the airbag (32), and the vent hole is developed in the process of deploying the airbag (32) with the gas generated by the inflator (31) when the vehicle collides. In the airbag device that opens (37b),
The overlapped base fabrics (36, 37) are joined by a separable joining part (39), the joining part (39) is separated by a load when the airbag (32) is deployed, and one end is a vent hole. A duct (48) that communicates with (37b) and that is closed at the other end in the vicinity of the outer peripheral portion of the airbag (32) by being joined to the joining portion (39); An air bag device characterized in that the vent hole (37b) is opened by unblocking the other end of the duct (48) by separating the portion (39).   The said joining part (39) extends in the spiral form toward the outer peripheral part from the center part of the said 1st, 2nd base fabric (36, 37), The any one of Claims 1-4 characterized by the above-mentioned. 2. The airbag device according to item 1.   The spiral joint (39) has at least one non-joint part (39a, 39b) where the joint is interrupted, and the non-joint part (39a, 39b) has a diameter of the joint part (39). The airbag device according to claim 5, wherein the airbag device is disposed at a position shifted in a circumferential direction with respect to a direction inner end.   A radially inner end of the joint portion (39) or an end portion where the joint portion (39) continues to the non-joint portion (39a, 39b) is directed to a central portion of the airbag (32). The airbag device according to any one of claims 1 to 6. When the internal pressure of the airbag (32) becomes a predetermined value or more without functioning the vent hole (37d) formed in at least one of the first and second base fabrics (36, 37), the predetermined value or more The airbag device according to any one of claims 1 to 7, further comprising a gas discharge portion (38a, 53) that discharges gas by being released by an internal pressure of the air bag.

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