JP6217047B2 - Knee airbag device for vehicle - Google Patents

Description

  The present invention relates to an improved vehicle knee airbag device.

  In many vehicles, an instrument panel is formed in the vehicle width direction in front of a steering wheel operated by a driver. Some of such vehicles include a knee airbag device that can protect an occupant's knees inside an instrument panel. The knee airbag device includes an inflator attached to the inside of an instrument panel and a bag body that can be deployed in front of an occupant's knee by the gas pressure of the inflator.

  As such a knee airbag device, for example, there is a technique disclosed in Patent Document 1. According to Patent Document 1, gas generated by an inflator is introduced into a bag body at the time of a vehicle collision. The bag body that has been folded and stored is directed toward the steering wheel and deployed along the instrument panel. The bag enters between the instrument panel and the occupant's knee, and the occupant's knee is protected.

  Here, at the time of deployment, the bag is deployed while being expanded. Since the instrument panel and the occupant's legs are close to each other, the occupant's legs may interfere when the bag is deployed.

JP 2005-186887 A

  It is an object of the present invention to provide a knee airbag device that has a high degree of certainty about the deployment operation of the bag body.

According to the invention of claim 1,
An inflator is attached to the inside of the instrument panel, and a bag body that can be deployed in front of an occupant's knee by the gas pressure of the inflator is formed by stitching two pieces of cloth into a bag shape. In the vehicle knee airbag device in which the tether is sewn to
The tether is disposed from the inflator-side end portion of the bag body toward the distal end portion in the deployment direction of the bag body, and is sutured by first to third stitching portions,
The first stitching portion is formed by stitching to one of the two cloths from the end on the inflator side toward the tip.
The second stitching part is formed by stitching to the other cloth of the two cloths from the end part on the inflator side toward the tip part,
The third suture portion is
From the end part on the inflator side to the end part on the tip part side, it is a part formed by sewing the tethers continuously or intermittently,
At the end portion on the inflator side, a portion separated from both the first stitching portion and the second stitching portion is stitched,
By stitching the vicinity of the first stitching portion and the vicinity of the second stitching portion at the end on the tip side,
When a gas is supplied from the inflator, a vehicular knee airbag device is provided which is configured such that the opening amount of the bag body decreases toward the tip portion.

As claimed in claim 2, preferably,
The third stitching portion is broken when the internal pressure of the bag body exceeds a predetermined value.

  The tether which constitutes a part of the invention according to claim 1 is arranged inside the bag body from the end portion on the inflator side toward the tip portion in the deployment direction of the bag body. The tether has a first stitched portion formed by stitching one of two fabrics from an end on the inflator side toward a tip in the deployment direction of the bag body, and an end on the inflator side And a second stitched portion formed by stitching to the other of the two fabrics from the tip toward the tip.

  Therefore, the opening amount of the bag body (the thickness of the bag body) when the gas is supplied from the inflator is determined by the dimensions from the first stitching portion to the second stitching portion of the tether.

  Here, the tether further includes a third stitching portion formed by stitching the tethers continuously or intermittently from the end portion on the inflator side to the end portion on the tip end side. Of the third stitched portion, at the end portion on the inflator side, a portion separated from both the first stitched portion and the second stitched portion is stitched. On the other hand, at the end on the distal end side, the vicinity of the first stitching portion and the vicinity of the second stitching portion are stitched.

  Therefore, when gas is supplied to the bag body from the inflator, the dimension from the first stitching portion to the second stitching portion at the end portion on the distal end portion side is the first stitching portion to the second stitching portion at the end portion on the inflator side. Shorter than As a result, the opening amount of the bag body becomes smaller toward the tip.

  Thereby, at the time of expansion | deployment of a bag body, a bag body can be reliably expand | deployed also between the instrument panel and passenger | crew's leg which are mutually close. Therefore, it is possible to provide a knee airbag device with high certainty about the deployment operation of the bag body.

  In the invention which concerns on Claim 2, a 3rd stitching | suture part is fractured | ruptured when the internal pressure of a bag body exceeds a predetermined value. Specifically, the bag body is developed in a state where the bag body becomes thinner toward the distal end portion, and further, gas is supplied by the inflator, thereby increasing the pressure in the bag body. Thereafter, when the internal pressure of the bag exceeds a predetermined value, the third stitching portion is broken. When the third stitching portion breaks, the tethers that have been stitched together open, and the dimension from the first stitching portion to the second stitching portion of the tether becomes longer. That is, since the dimension of the part which controlled the opening amount of the bag body in the tether becomes longer, the opening amount of the bag body also increases.

  By increasing the opening amount of the bag, the degree of adhesion between the occupant and the bag increases. Therefore, the protection performance of the passenger can be enhanced.

1 is a schematic diagram of a vehicle having a knee airbag device according to Embodiment 1 of the present invention. It is a disassembled perspective view of the bag body shown by FIG. It is a top view of the bag body shown by FIG. It is a perspective view of the bag shown by FIG. FIG. 5 is a cross-sectional view of the bag shown in FIG. 4. It is an effect | action figure explaining until the bag body of the knee airbag apparatus by Example 1 is expand | deployed ahead of a passenger | crew's knee. It is an effect | action figure explaining until the bag body shown by FIG. 6 is expand | deployed further. It is a schematic diagram of the bag which comprises the knee airbag apparatus by Example 2 of this invention. It is a schematic diagram of the bag which comprises the knee airbag apparatus by Example 3 of this invention. It is a schematic diagram of the bag which comprises the knee airbag apparatus by Example 4 of this invention. It is a schematic diagram of the bag which comprises the knee airbag apparatus by Example 5 of this invention.

Embodiments of the present invention will be described below with reference to the accompanying drawings. In the description, left and right refer to the left and right based on the vehicle occupant, and front and rear refer to the front and rear based on the traveling direction of the vehicle. In the figure, Fr indicates the front, Rr indicates the rear, L indicates the left when viewed from the occupant, R indicates the right when viewed from the occupant, Up indicates the top, and Dw indicates the bottom.
<Example 1>

  The structure of the knee airbag device according to the first embodiment will be described with reference to FIGS.

  As shown in FIG. 1, a vehicle 10 has a vehicle compartment 12 with a windshield 11 as a boundary. An instrument panel 13 is attached to the front of the vehicle compartment 12 in the vehicle width direction. A steering column cover 14 is attached to the instrument panel 13. A steering wheel 15 that is covered by the steering column cover 14 and is operated by the occupant Mn is provided.

  A knee airbag device 20 that protects the knee Kn of the occupant Mn is housed inside the instrument panel 13. The knee airbag device 20 mainly includes an inflator 30 that generates gas when the vehicle 10 collides, and a bag body 40 that can be deployed in front of the knee Kn of the occupant Mn by the gas pressure of the inflator 30. The bag body 40 is folded and accommodated inside the instrument panel 13.

  As shown in FIGS. 2 and 3, the bag body 40 is formed in a bag shape by sewing the edges of the two cloths 51 and 52. Inside the bag body 40, a first tether 60 and a second tether 70 are stitched to direct the opening amount of the bag body 40 and the flow of gas when the bag body 40 is deployed.

  In particular, as shown in FIG. 3, the bag body 40 includes a base end portion 41 connected to the inflator (FIG. 1, reference numeral 30), and an extension portion 42 extending away from both ends of the base end portion 41. , 42, parallel portions 44, 44 extending parallel to each other from the distal ends of the respective extended portions 42, 42, and a distal end portion 46 extending parallel to the base end portion 41 so as to connect the distal ends of the parallel portions 44, 44. . Both the parallel portions 44 and 44 extend substantially perpendicular to the base end portion 41 and the tip end portion 46. There is a central portion 47 between the parallel portions 44 and 44.

  Referring again to FIG. 2, the cloths 51 and 52 both have a substantially hexagonal shape in which two adjacent corners of a rectangle are cut off. One cloth 51 is developed to face the instrument panel (FIG. 1, reference numeral 13). One cloth 51 is appropriately referred to as a first cloth 51. The other cloth 52 is unfolded so as to face the occupant (FIG. 1, symbol Mn). The other cloth 52 is appropriately referred to as a second cloth 52.

  The first tether 60 is formed by folding a rectangular cloth so that the dimension in the short direction is halved. As a result, the first tether 60 is formed with a first rectangular portion 61, a second rectangular portion 62, and a fold line 63. The first rectangular portion 61 and the second rectangular portion 62 are sewn together. Details of the stitched portion (third stitched portion 66) will be described in FIG.

  Similarly to the first tether 60, the second tether 70 is also formed with a first rectangular portion 71, a second rectangular portion 72, and a fold line 73. The first rectangular portion 71 and the second rectangular portion 72 are stitched together (third stitching portion 76).

  In the bag body 40, the first tether 60 and the second tether 70 are configured so that their folding lines 63 and 73 face each other and draw a substantially V shape from the center of the base end portion 41 toward the corner of the tip end portion 46. Has been placed.

  Referring also to FIG. 4, the side end 61 a in the longitudinal direction of the first rectangular portion 61 of the first tether 60 and the first cloth 51 are stitched together to form a first stitched portion 64. Further, the side end 62a in the longitudinal direction of the second rectangular portion 62 and the second cloth 52 are stitched together to form a second stitched portion 65.

  Similarly, in the second tether 70, the side ends 71a and 72a in the longitudinal direction of the rectangular portions 71 and 72 are sewn to the cloths 51 and 52, so that a first stitching portion 74 and a second stitching portion 75 are formed.

  Next, the 3rd stitching part 66 formed when the 1st rectangular part 61 and the 2nd rectangular part 62 of the 1st tether 60 are stitched together is explained. The third stitching portion 66 is formed so as to move away from the fold line 63 from the proximal end portion 41 side toward the distal end portion 46 side in the bag body deployment direction.

  In other words, the third stitching portion 66 is formed at a site separated from both the first stitching portion 64 and the second stitching portion 65 at least at the end portion 60a on the inflator (FIG. 1, reference numeral 30) side, and the distal end portion. At the end portion 60 b on the 46 side, it is formed in the vicinity of the first stitching portion 64 and in the vicinity of the second stitching portion 65.

  Further, the third stitching portion 76 formed by stitching the rectangular portions 71 and 72 of the second tether 70 together is also formed in the same manner as the third stitching portion 66 of the first tether 60.

  That is, the third stitching portion 76 is formed at least at the end portion 70a on the inflator side and away from both the first stitching portion 74 and the second stitching portion 75, and at the end portion 70b on the tip end portion 46 side, It is formed in the vicinity of the first stitching portion 74 and in the vicinity of the second stitching portion 75.

  Next, the operation of the present invention will be described. As shown in FIG. 6, when the vehicle 10 collides, the inflator 30 supplies gas to the bag body 40, and the bag body 40 in the housed state is deployed in front of the knee Kn of the occupant Mn. Hereinafter, the development of the bag body 40 will be described by dividing it into the opening amount of the bag body 40 (thickness of the bag body 40) and the gas flow in the bag body 40.

  First, the opening amount of the bag body 40 will be described. As shown in FIG. 4, the side end 61 a in the longitudinal direction of the first rectangular portion 61 of the first tether 60 and the first cloth 51 are stitched together to form a first stitched portion 64. Further, the side end 62a in the longitudinal direction of the second rectangular portion 62 and the second cloth 52 are stitched together to form a second stitched portion 65. (The second tether 70 has the same configuration as the first tether and will not be described below.)

  Since the bag body 40 is stitched to the first tether 60 via the first stitching portion 64 and the second stitching portion 65, the opening amount of the bag body 40 is from the first stitching portion 64 to the second stitching portion 65. Determined by the dimensions of

  Here, the first tether 60 is also formed with a third stitching portion 66 by stitching the first rectangular portion 61 and the second rectangular portion 62 together. Specifically, the third stitching portion 66 is formed so as to move away from the folding line 63 from the proximal end portion 41 side toward the distal end portion 46 side in the deployment direction of the bag body 40. That is, the third stitching portion 66 comes closer to both the first stitching portion 64 and the second stitching portion 74 as it goes toward the distal end portion 46 side.

  In other words, as shown in FIG. 5, the first end is advanced from the base end 41 side shown in FIG. 5A toward the tip end 46 side shown in FIGS. 5B and 5C. The overlapped dimensions of the rectangular portion 61 and the second rectangular portion 62 are increased, and the first cloth 51 and the second cloth 52 are pulled toward the inside of the bag body 40 so as to be close to each other. Moreover, the parallel parts 44 and 44 of a bag body will be in the slack state to the front-end | tip part 46 side shown by FIG.5 (b), (c).

  Therefore, as shown in FIG. 6, the opening amount of the bag body 40 decreases as it moves toward the distal end portion 46. Therefore, when the bag body 40 is deployed, the bag body can be reliably deployed between the instrument panel 13 and the legs of the occupant Mn that are close to each other.

  Further, in the knee airbag device 20 of the present invention, as shown in FIG. 6, even after the bag body 40 enters between the instrument panel 13 and the knee Kn of the occupant Mn, the inflator 30 applies the bag body 40 to the bag body 40. Gas supply continues. When the gas supply continues, the pressure in the bag body 40 increases, and when the internal pressure of the bag body 40 exceeds a predetermined value, the third stitching portion (reference numeral 66 in FIG. 5) breaks.

  When the third stitching portion 66 is broken, as shown in FIG. 7B, the first rectangular portion 61 and the second rectangular portion 62 that are sewn together open so as to be separated from each other, and are folded over. The part disappears. As a result, the dimension from the first stitching portion 64 to the second stitching portion 65 of the first tether 61 becomes long. The looseness which has arisen in the parallel parts 44 and 44 of the bag body 40 is also eliminated, and the opening amount of the bag body 40 is increased.

  Therefore, when the opening amount of the bag body 40 is increased, the degree of adhesion between the occupant Mn and the bag body 40 is increased as shown in FIG. Therefore, the protection performance of passenger | crew Mn can be improved.

  As shown in FIG. 3, the third stitching portion 66 is sewn in the end portion 60 a on the base end portion 41 side while being separated from both the first stitching portion 64 and the second stitching portion 65. It is only necessary that the vicinity of the first stitching portion 64 and the vicinity of the second stitching portion 65 are stitched at the end portion 60b on the distal end portion 46 side. In the present embodiment, the third stitching portion 66 is continuously formed from the proximal end portion 41 side toward the distal end portion 46 side, but may be formed intermittently.

  In this embodiment, two tethers, the first tether 60 and the second tether, are arranged in the bag body 40, but one or three or more tethers may be provided.

  Next, the gas flow in the bag body 40 will be described. As shown in FIG. 3, the first tether 60 and the second tether 70 are opposed to each other by folding lines 63 and 73, and are substantially V-shaped from the center of the base end portion 41 toward the corner of the tip end portion 46. It is arranged to draw.

  Therefore, when gas is supplied to the bag body 40 from the inflator (FIG. 6, reference numeral 30), the vicinity of the end portion 60a of the first tether 60 and the end portion 70a of the second tether 70 becomes a barrier, and the gas is supplied to the inflator (FIG. 6, it becomes difficult to flow on the extension line of the supply port of 30). On the other hand, the gas tends to flow on the outer surface (the parallel part 44 side) of the V shape. Thereafter, the gas reaches both ends of the front end portion 46 of the bag body 40 and flows into the center of the bag body 40 so as to be folded back. Therefore, the central portion 47 of the bag body 40 swells later than the vicinity of the parallel portions 44 and 44 that are both ends of the bag body 40.

  As described above, the bag body 40 in which the central portion 47 swells later than the parallel portions 44 and 44 is suitable for, for example, a vehicle in which the steering column cover 14 is provided on the foot side.

For example, when the steering column cover 14 is provided further downward, when the bag body 40 is deployed, the steering column cover 14 may become a convex portion and interfere with the developing bag body 40. However, if the central portion 47 swells with a delay, that is, if the central portion 47 is recessed, a space is created between the steering column cover 14 and the bag body 40. Therefore, the bag body 40 can be reliably deployed between the instrument panel 13 and the legs of the occupant Mn that are close to each other.
<Example 2>

  Next, a second embodiment of the present invention will be described with reference to FIG. As shown in FIG. 8, the first to fourth tethers 60 </ b> A, 70 </ b> A, 80 </ b> A, 90 </ b> A are arranged in the bag body 40 </ b> A so as to draw a letter W from the center of the base end portion 41 toward the tip end portion 46. ing. Other basic configurations are the same as those of the knee airbag device according to the first embodiment. About the part which is common in Example 1, while using a code | symbol, detailed description is abbreviate | omitted.

  When the tether is arranged so as to draw the letter W, the gas is supplied to the side surfaces of the first to fourth tethers 60A, 70A, 80A, 90A in which the letter W is drawn, that is, the parallel parts 44 in the bag body 40A. 44 and the central portion 47.

When the gas flows through the parallel portions 44 and 44 of the bag body 40A, that is, the edge of the bag body 40, the overall shape of the bag body 40A that is folded and stored is formed in a short time. At the same time, gas flows through the central portion 47, so that the parallel portions 44 and 44 and the central portion 47 swell simultaneously. Therefore, the arrangement of the first to fourth tethers 60A, 70A, 80A, 90A in the present embodiment is suitable when it is desired to develop the bag thickness uniformly in a short time.
<Example 3>

  Next, Embodiment 3 of the present invention will be described with reference to FIG. As shown in FIG. 9, the first tether 60 </ b> B and the second tether 70 </ b> B are arranged to draw a reverse V shape from the center of the base end portion 41 toward the corner of the tip end portion 46. Other basic configurations are the same as those of the knee airbag device according to the first embodiment. About the part which is common in Example 1, while using a code | symbol, detailed description is abbreviate | omitted.

  When the tether is arranged so as to draw an inverted V shape, the gas flows through the central portion 47 of the bag body 40B, and flows toward the parallel portions 44 that are both ends of the bag body 40B after reaching the distal end portion 46. Therefore, the parallel part 44 swells later than the central part 47.

The bag body 40B deployed in this manner is suitable for an instrument panel in which convex portions are formed on the left and right sides of the column cover, for example, in the design of the vehicle.
<Example 4>

  Next, a fourth embodiment of the present invention will be described with reference to FIG. As shown in FIG. 10, the first to fourth tethers 60 </ b> C, 70 </ b> C, 80 </ b> C, 90 </ b> C are arranged in the bag body 40 </ b> C so as to draw a letter W from the center of the base end portion 41 toward the tip end portion 46. ing. Other basic configurations are the same as those of the knee airbag device according to the first and second embodiments. About the part which is common in Example 1, 2, while using a code | symbol, detailed description is abbreviate | omitted.

  When the tether is arranged so as to draw the letter W, the gas is supplied to the side surfaces of the first to fourth tethers 60C, 70C, 80C, 90C that draw the letter W, that is, the parallel parts 44 in the bag body 40D, 44 and the central portion 47.

  Further, the end portions 60Cb, 70Cb, 80Cb, and 90Cb of the first to fourth tethers 60C to 90C are in contact with the distal end portion 46 of the bag body 40C. Therefore, the gas that passes through the parallel parts 44 and 44 and reaches both ends of the tip part 46 does not flow into the center. Furthermore, the end portions 60Ca and 70Ca of the first and second tethers 60C and 70C are arranged so as to overlap each other. The same applies to the end portions 80Ca and 90Ca of the third and fourth tethers 80C and 90C. Therefore, the gas does not easily flow from the overlapping end portion toward the tip end portion 46.

  That is, in the present embodiment, compared with the second embodiment, the gas easily flows only into the parallel portions 44 and 44 and the central portion 47. Therefore, compared with Example 2, this example is suitable for a case where it is desired to develop the bag body uniformly in a shorter time.

  In addition, semicircular openings 67C, 77C, 87C, and 97C are formed along the folding lines 63C, 73C, 83C, and 93C in the first to fourth tethers 60C to 90C. After the third stitching portions 66C, 76C, 86C, and 96C are broken, the first to fourth tethers 60C to 90C are opened, and the openings 67C, 77C, 87C, and 97C are circular. The gas enters the space surrounded by the first to fourth tethers 60C to 90C and the tip end portion 46 through the circular openings 67C to 97C, and the expansion of the bag body 40C is completed.

Note that the end portions 60Ca and 70Ca, 80Ca and 90Ca may be arranged apart from each other without overlapping. Furthermore, the shape of the openings 67C, 77C, 87C, 97C may be rectangular, and the number of openings can be increased or decreased. Thus, the behavior of the bag body development can be changed by appropriately changing and combining the arrangement of the tethers and the shape and number of the openings.
<Example 5>

  Next, a fifth embodiment of the present invention will be described with reference to FIG. As shown in FIG. 11, the first tether 60 </ b> D and the second tether 70 </ b> D are arranged to draw a reverse V shape from the center of the base end portion 41 toward the corner of the tip end portion 46. Other basic configurations are the same as those of the knee airbag device according to the first, third, and fourth embodiments. About the part which is common in Example 1, 3, and 4, while using a code | symbol, detailed description is abbreviate | omitted.

  In the present embodiment, the end 60Db and the second tether 70Db of the first tether 60D are in contact with the tip 46 of the bag body 40D. Therefore, the gas flows through the central portion 47 of the bag body 40D, but does not flow toward the parallel portions 44, 44 even if it reaches the distal end portion 46.

  Compared with the third embodiment, since the gas flows only into the central portion 47, the bag body 40D can be deployed in a shorter time than the third embodiment.

  In addition, semicircular openings 67D and 77D are formed in the first tether 60D and the second tether 70D along the folding lines 63D and 73D. After the third stitching portions 66D and 76D are broken, the first tether 60D and the second tether 70D are opened, and the openings 67D and 77D are circular. The gas flows into the parallel portions 44 and 44 through the circular openings 67D and 77D, and the expansion of the bag body 40D is completed.

  The vehicle knee airbag device according to the present invention is suitable for a passenger car.

DESCRIPTION OF SYMBOLS 13 ... Instrument panel 20 ... Knee airbag apparatus 30 ... Inflator 40 ... Bag body 41 ... Base end part 46 ... Tip part 51 ... 1st cloth (one cloth)
52. Second cloth (the other cloth)
60, 60A ... 1st tether 64 ... 1st stitching part 65 ... 2nd stitching part 66 ... 3rd stitching part 67C ... Opening part 70, 70A ... 2nd tether 74 ... 1st stitching part 75 ... 2nd stitching part 76 ... Third suture part 80A ... Third tether 90A ... Fourth tether Mn ... Crew Kn ... Knee

Claims (2)

An inflator is attached to the inside of the instrument panel, and a bag body that can be deployed in front of an occupant's knee by the gas pressure of the inflator is formed by stitching two pieces of cloth into a bag shape. In the vehicle knee airbag device in which the tether is sewn to
The tether is disposed from the inflator-side end portion of the bag body toward the distal end portion in the deployment direction of the bag body, and is sutured by first to third stitching portions,
The first stitching portion is formed by stitching to one of the two cloths from the end on the inflator side toward the tip.
The second stitching part is formed by stitching to the other cloth of the two cloths from the end part on the inflator side toward the tip part,
The third suture portion is
From the end part on the inflator side to the end part on the tip part side, it is a part formed by sewing the tethers continuously or intermittently,
At the end portion on the inflator side, a portion separated from both the first stitching portion and the second stitching portion is stitched,
By stitching the vicinity of the first stitching portion and the vicinity of the second stitching portion at the end on the tip side,
The vehicle knee airbag device, wherein when the gas is supplied from the inflator, the amount of opening of the bag body decreases toward the tip.   2. The vehicle knee airbag device according to claim 1, wherein the third stitching portion is broken when an internal pressure of the bag body exceeds a predetermined value.

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