JP6567411B2 - Airbag device - Google Patents

Description

  The present invention relates to an airbag apparatus including an airbag that can be inflated and deployed by a gas supplied from a gas generator such as an inflator when a vehicle collides. In particular, the present invention relates to an airbag device that prevents an airbag from being inflated and deployed at a stretch in the front-rear direction from the initial stage of inflation and deployment, restrains an occupant softly, and then inflates and deploys the airbag to a final shape.

  Conventionally, an air bag device has been used to protect an occupant during a vehicle collision or the like, and many automobiles are equipped with an air bag device. As an airbag device, it is used in various places for protecting passengers and pedestrians for drivers, for passenger seats, for windows on the side of the passenger compartment, and for side portions of the seat back. In the following, a driver airbag device will be described as an example.

  As an airbag device having a configuration that prevents the airbag from being inflated and deployed at a stretch in the front-rear direction at the initial stage of inflation and deployment, an airbag device using a fracture joint (see Patent Document 1) has been proposed.

  In the airbag apparatus of Patent Document 1 shown in FIG. 7, the airbag 30 is configured in a bag shape by sewing the outer peripheral portions of two base fabrics. The two base fabrics are joined by a fracture joint 32 that continuously extends from the radially inner side of the airbag 30 toward the outer circumferential direction. When the airbag 30 is inflated and deployed, the fracture joint portion 32 is sequentially fractured from the radially inner side to the outer circumferential direction of the airbag 30 by the deployment pressure, and the two pieces joined by the fracture joint portion 32 The joints in the base fabric are separated.

  By joining the two base fabrics at the rupture joint portion 32, it is possible to prevent the airbag from being inflated and deployed at a stretch in the front-rear direction at the initial stage of inflation and deployment, thereby restraining the occupant softly. Then, when the separation of the fracture joint portion is completed, the airbag is inflated and deployed in a final shape flat in the front-rear direction, and it is explained that a sufficient restraining force can be exhibited. In FIG. 7, reference numeral 31 denotes an opening surrounding an inflator (not shown).

JP 2005-193881 A

  In the airbag device described in Patent Document 1, the fracture joint portion 32 that joins two base fabrics that form the airbag 30 in a bag shape on the center side is formed in a continuous shape in a plan view. Has been. However, when the rupture joints 32 are formed in respective regions in the vertical and horizontal directions in the plan view of the airbag 30, zigzag, arcuate curved portions and straight portions are alternately arranged as the planar shape of the rupture joint 32. In other words, it is formed in a shape that is arranged in the shape, a shape in which the straight portion is refracted, or the like. And in each shape, the folding | returning part is formed in order to change a direction.

  These folded portions are formed as folded portions from the straight line portion, or are formed as folded portions from the arcuate curved portion. When the fracture joint portion sequentially breaks from the radially inner side to the outer circumferential direction of the airbag 30 due to the deployment pressure at the time of inflation and deployment, the fracture is smoothly and continuously performed in the connection section connected to the folded portion. Must be done to. In particular, when the folded portion is bent at a right angle or an obtuse angle, the break may stop at the folded portion until a higher development pressure is reached.

  That is, if the situation where the straight part and the arcuate curved part are continuously broken continues and continues to the folded part, the airbag 30 can be smoothly inflated and deployed as designed. For this reason, man-hours such as adjustment of the type of sewing thread at the fracture joint, the thickness of the sewing thread, and the sewing interval (pitch) are required.

  The present invention has a simple configuration and can form a connection section that is continuous with the folded portion in the fracture joint portion in a continuous and smooth state, and the fracture at the fracture joint portion is maintained at a constant speed. An object of the present invention is to provide an airbag device that can be kept running.

In order to solve the above problems, an airbag device according to the present invention is an airbag device including an airbag that can be inflated and deployed by gas. The airbag is formed in a bag shape, and the bag is in a deflated state. The first base fabric portion and the second base fabric portion that overlap each other are joined by a fracture joint portion that breaks at a predetermined deployment pressure during expansion and deployment,
The planar shape of the fracture joint is a linear part having at least one curved folded part, and the predetermined section from the folded part of the linear part is formed as a clothoid curve. It is said.

  By providing the above-described configuration, in the present invention, since the predetermined section from the folded portion can be formed with a clothoid curve in the fracture joint portion, the linear portion forming the fracture joint portion is continuously smooth. It can be configured as a single line. And when a fracture | rupture junction part fractures | ruptures by the expansion | deployment pressure at the time of expansion | deployment, a fracture | rupture junction part can be continued to fracture | rupture, maintaining a constant speed in a continuous and stable state. As a result, the airbag can be inflated and deployed safely and smoothly as designed with a simple configuration.

It is the rear view (a) which shows the fracture | rupture junction part of an airbag, and the rear view (b) which shows another fracture | rupture junction part. Example 1 It is explanatory drawing which shows the various elements of a clothoid curve. They are the principal part enlarged view (a) which shows the connection area in a fracture | rupture joining part, and the principal part enlarged view (b) which shows the connection area in another fracture | rupture joining part. Example 1 It is the rear view (a) which shows a fracture | rupture joined part, and the rear view (b) which shows another fracture | rupture joined part. (Example 2) It is the rear view (a) which shows the arrangement configuration of a vent hole, and the rear view (b) which shows the modification in the arrangement configuration of a vent hole. (Example 3) It is sectional drawing at the time of expansion | deployment expansion | deployment in the IV-IV cross section of FIG. Example 1 It is a rear view of an airbag apparatus. (Conventional example)

  Embodiments of the present invention will be specifically described below with reference to the accompanying drawings. As an airbag device of the present invention, a configuration in which an airbag module is mounted on a boss plate of a steering wheel will be described as an example. However, the airbag device according to the present invention is not limited to a driver airbag device, and may be a side airbag, a curtain airbag, a knee airbag, or the like as long as it has a fracture joint. It can be used as a device.

  Therefore, even if it is a structure other than the structure demonstrated below, if it is a shape and arrangement | positioning structure which can solve the subject of this invention, those shapes and arrangement | positioning structures can be employ | adopted. For this reason, this invention is not limited to the Example demonstrated below, A various change is possible.

(Constitution)
The structure of the airbag apparatus 1 which concerns on Example 1 of this invention is demonstrated using FIG. In FIG. 6, the initial state where the airbag 2 is inflated and deployed is shown by a thin line, and the state where the airbag device 1 is mounted in the steering wheel is shown by a cross-sectional view. The steering wheel includes an annular rim portion 3 that is gripped by the driver, a boss portion (not shown) located inside the rim portion 3, and a plurality of spoke portions that connect the rim portion 3 and the boss portion. Composed. A substantially cylindrical boss 5 fitted to the steering shaft is provided on the back surface of the boss portion.

  The airbag device 1 is arranged so as to cover the front surface of the boss portion, and includes a base plate 4 made of a synthetic resin or a metal plate, a bag-like airbag 2, an inflator 7 for generating inflation gas, and the like made of resin. It is provided in the airbag cover 6. The base plate 4 is attached to the steering wheel via a horn plate or a bracket portion, and the airbag 2, the inflator 7, and the airbag cover 6 are attached to the base plate 4. And the airbag 2 is accommodated in the airbag cover 6 in the state folded small.

  In FIG. 6, the airbag cover 6 shows a state before the airbag 2 is inflated and deployed, and when the airbag 2 is inflated and deployed by the gas from the inflator 7, the airbag 2 that is inflated and deployed. Thus, the airbag 2 can be broken along a tear line provided on the back surface of the airbag cover 6 on the passenger side, and the airbag 2 can be inflated to the outside of the airbag cover 6.

The airbag 2 is configured in a bag shape by folding the outer peripheral portions 9 of the first base fabric 2 a and the second base fabric 2 b together and sewing the folded portion 2 c with the sewing portion 8.
In addition, as a structure which forms the airbag 2 in a bag shape, it is not limited to the shape which sewn the outer peripheral parts of the 1st base fabric 2a and the 2nd base fabric 2b, It can form in a bag shape. If it is a structure, the suitable structure comprised using the base fabric of an airbag 1 sheet, 3 sheets, 4 sheets, etc. can be employ | adopted.

  As shown in FIG. 1, the second base fabric 2 b is formed with an opening 15 surrounding the inflator 7. The inflator 7 is accommodated in the airbag 2 through the opening 15, and the airbag 2 is stored in the inflator 7. And the base plate 4.

  The second base fabric 2b has a vent for discharging a part of the gas filled in the airbag 2 in order to restrain the occupant softly by restraining the repulsive force when the occupant is restrained by the inflated airbag 2 A hole 16 is formed.

  Then, at the initial stage when the airbag 2 is inflated and deployed, the central portion side where the first base fabric 2a and the second base fabric 2b overlap is broken and joined so that the airbag 2 does not inflate and deploy all the way to the final shape. It is joined by the part 10.

  As will be described later, when the airbag 2 starts to be inflated and deployed by the gas supplied from the inflator 7, the airbag 2 is not inflated and deployed at a stretch to the final shape by the fracture joint 10, and as shown in FIG. The side part and the part in the left-right direction (partial part inflated in the left-right direction are not shown) are tightened.

  By forming in this way, a small bulge portion can be formed on the passenger's head side, and a small bulge portion can also be formed on the left-right direction side. And a protrusion part with a large pressure-receiving area can be formed in an abdominal part or a knee side. And when a passenger | crew contacts the airbag 2, a passenger | crew can be restrained by a soft reception efficiently.

  Thereafter, with the occupant restrained by the airbag 2, the fracture joint 10 is ruptured, so that the airbag 2 can be inflated and deployed to the final shape, and can continue to restrain the occupant safely.

  As shown in FIGS. 1 (a) and 1 (b), the shape of the fracture joint 10 is formed in both the upper side and the left / right direction by arranging an opening 15 surrounding the inflator 7 at a substantially central portion of the airbag 2. ing. 3 (a) and 3 (b), the fracture joint 10 is formed as a single linear part, and the planar shape of the fracture joint 10 is a straight section 11 on both ends. Further, a curved section 12 is formed, and a folded portion 13 is formed between the ends of the adjacent sections 11 and 12 to connect them. A clothoid curve, which will be described later, is formed in a predetermined section (hereinafter, referred to as a connection section 14) that is continuous with the folded portion 13.

  In addition to the planar shape shown in FIGS. 1A and 1B, the planar shape of the fracture joint 10 is formed as the planar shape shown in FIGS. 4A and 4B as will be described later. be able to. In addition, the planar shape of the fracture | rupture joining part 10 shown here is an illustration, Comprising: If it is a planar shape which can function as the fracture | rupture joining part 10, it can form in another planar shape.

(Shape in the connection section of the fracture joint)
The shape of the connecting section 14 in which the straight section 11, the curved section 12, and the folded portion 13 are continuously connected will be described with reference to FIGS. Initially, the clothoid curve which comprises the connection area 14 is demonstrated using FIG.

  A clothoid curve is a kind of relaxation curve. Taking a car as an example, a clothoid is the locus that travels when a car running at a constant speed travels while rotating the steering wheel at a constant angular speed. It becomes a curve.

  A clothoid curve is demonstrated using the figure shown in FIG. The curve shown in FIG. 2 has a symmetrical shape with respect to a straight line drawn in the vertical direction of the figure. As the shape on one side of the straight line drawn in the vertical direction, a straight section is formed, and the end thereof is the starting point KA of the clothoid curve. The clothoid curve is formed to the end point KE, and the end point KE is a continuous curve in which one end of a circular curve is connected. On the straight line drawn in the vertical direction, the left continuous curve and the right continuous curve have the same tangent.

  In FIG. 2, the symbol R indicates the radius of curvature at the end point KE, and the symbol L indicates the clothoid curve length from the start point KA to the end point KE. The symbol LC indicates the length of the circular curve, that is, the length between the end points KE of the clothoid curve. Reference sign IP indicates an intersection when a linear section that is symmetrical is extended. Reference sign D indicates the tangent length from the start point KA to the intersection point IP.

At this time, the clothoid curve can be expressed as R × L = A ² . A is a constant having a dimension of length and is called a clothoid parameter. In the following, the planar shape of the fracture joint 10 will be described with reference to FIGS. 3A and 3B. The symbols and curve formulas representing the clothoid curve are the same as those used in FIG. I will use it.

  FIG. 3A shows a case where a cap-like curved shape is formed as the planar shape of the fracture joint portion 10, and FIG. 3B shows a planar shape of the fracture joint portion 10 where the central portion has an arc shape. The case where it forms in the shape of the raised mountain shape is shown.

  First, the planar shape of the fracture joint 10 shown in FIG. 3A will be described based on the clothoid curve shown in FIG. In Fig.3 (a), the site | part enclosed with the dotted line in the fracture | rupture joining part 10 illustrated on the upper left is shown in the state expanded to the lower right side.

  As shown in FIG. 3 (a), the cap-shaped head is formed as a curved section 12, and connection sections 14 each consisting of a clothoid curve are formed on both ends of the curved section 12, respectively. It is continuous. In each of the connection sections 14, the turn-back portions 13 are continuous.

  In the planar shape of the fracture joint 10 shown in FIG. 3B, the part surrounded by a dotted line in the fracture joint 10 shown in the upper left is shown in a state where it is enlarged to the lower right.

  As shown in FIG. 3 (b), both end portions of the fracture joint 10 are formed as linear sections 11, and each linear section 11 is a folded portion via a connecting section 14 made of a clothoid curve. 13 is continuous.

Any of the clothoid curves shown in FIGS. 3A and 3B can be expressed as R × L = A ² and R / 3 ≦ A ≦ R. A is a constant having a dimension of length and is called a clothoid parameter. As an example, in FIG. 3A, the connection section 14 is drawn with R = 25 and L = 23, and in FIG. 3B, the connection section 14 is drawn with R = 40 and L = 32. Is.

(effect)
By configuring the fracture joint 10 in this way, in FIG. 3A, the start point KA of the connection section 14 made of a clothoid curve is continuous with the curved section 12, and the end point KE of the connection section 14 is , And continues to the turn-up portion 13. In addition, the connection state at the start point KA and the end point KE is a smooth continuous connection, and the breaking speed when the fracture joint 10 breaks from one end side changes at the start point KA and the end point KE. Without breakage, the fracture joint 10 can be broken at a constant breaking speed.

  Moreover, in FIG.3 (b), the fracture | rupture junction part 10 fractured | ruptured from the linear area 11 is a smooth continuous connection to the linear area 11, the connection area 14, and the folding | returning part 13, and is a fracture | rupture junction part. When 10 breaks from the linear section 11 at both ends, the breaking speed does not change at the start point KA and the end point KE, and can be broken at a constant breaking speed.

  Moreover, by setting the clothoid parameter A of the clothoid curve forming the connection section 14 to R / 3 ≦ A ≦ R, the fracture joint 10 can be broken at a constant breaking speed. When the value of the clothoid parameter A is set to a value smaller than R / 3 or larger than R, the rupture is not performed at a constant rupture speed over the entire length of the fracture joint 10. Therefore, it is desirable that the clothoid parameter A is set to R / 3 ≦ A ≦ R.

  Thereby, the airbag 2 can be inflated and deployed as designed, and the passenger can be restrained safely. Moreover, even in a state where the occupant covers the steering wheel close to the steering wheel (so-called OOP), in the initial inflation state of the airbag 2, the airbag 2 is inflated slightly upward and laterally. As shown in FIG. 6, the downward direction of the airbag 2 can be quickly inflated to a state in which the airbag 2 projects in the front-rear direction as compared to the central portion of the airbag 2. As a result, the airbag 2 is quickly deployed downward, and the occupant restraint performance during proximity deployment is improved.

  The air bag device 1 configured as described above can greatly improve the occupant restraint performance called so-called belly insertion performance. In the conventional airbag device, in order to improve the performance of entering the stomach, it has been dealt with by setting a rectifying cloth or the like, but there is a problem that the cost becomes considerably high in order to provide the rectifying cloth. . However, in the present invention, the shape of the rupture joint 10 is devised, so that the belly penetration performance can be significantly improved at the cost of sewing the rupture joint 10.

  Moreover, since the fracture | rupture joining part 10 has the structure made to continue in the connection area 14 which consists of a clothoid curve, the fracture | rupture of the fracture | rupture joining part 10 does not stop on the way at the time of expansion | deployment of the airbag 2. FIG. For this reason, it is not necessary to adjust the type of sewing thread, the thickness of the sewing thread, and the sewing interval (pitch) at the conventional breaking joint. And a high passenger | crew restraint performance can be maintained, without reducing a passenger | crew restraint performance.

  The structure of the airbag apparatus 1 which concerns on Example 2 of this invention is demonstrated using Fig.4 (a), (b). In Example 2, the configuration of the fracture joint 10 is such that the fracture joint 10 disposed on the upper side formed in Example 1 is eliminated. Other configurations are the same as those in the first embodiment, and the same reference numerals as those used in the first embodiment are used for the same configurations as the first embodiment. And the overlapping description regarding the member is omitted.

  4A shows a configuration in which the fracture joint 10 disposed on the upper side in the configuration of FIG. 1A is eliminated, and FIG. 4B shows an upper side in the configuration of FIG. 1B. It has the structure which eliminated the fracture | rupture joining part 10 distribute | arranged to (3).

(effect)
The configuration of the fracture joint 10 is such that the fracture joint 10 disposed on the upper side is eliminated, so that at the initial stage when the airbag 2 is inflated and deployed at the time of close deployment (OPP), the airbag 2 Only the left-right direction is restricted, and it can be quickly expanded and deployed in the up-down direction. Thereby, in addition to the belly insertion performance which is the effect in Example 1, the rim insertion performance (performance in which the airbag 2 bulges from the boss portion to the occupant side from between the rim portion) is also improved.

  The structure of the airbag apparatus 1 which concerns on Example 3 of this invention is demonstrated using Fig.5 (a), (b). In Example 3, the formation site of the vent hole 16 is specified, and the formation position of the fracture joint 10 is the same as that in FIG. 1A shown in Example 1. Therefore, the same components as those used in the first embodiment are used for the same configurations as those in the first embodiment. And the overlapping description regarding the member is omitted.

  FIG. 5A shows a region 17 where the vent hole 16 is not hidden from the opening 15 in the central portion of the airbag 2 in the arrangement configuration of the fracture joint 10 shown in FIG. FIG. 1B shows a region 18 where the vent hole 16 is hidden from the opening 15 in the central portion of the airbag 2 in the arrangement configuration of the fracture joint 10 shown in FIG.

(effect)
As shown in FIG. 5A, the vent hole 16 is formed in the region 17 where the vent hole 16 is not hidden by the fracture joint 10 from the opening 15 at the center of the airbag 2, or as shown in FIG. As described above, by forming the vent hole 16 in the region 18 where the vent hole 16 is hidden by the fracture joint 10 from the opening 15 at the center of the airbag 2, the air is exhausted from the vent hole 16 in the initial state of inflation of the airbag 2. The amount of gas to be produced can be changed, and the timing at which the fracture joint 10 breaks can be easily adjusted.

  That is, by adjusting the formation position of the vent hole 16, it is possible to adjust the formation timing when the airbag 2 is inflated and deployed and the fracture joint 10 is not broken or when it is broken and deployed to the final shape. In addition, the effects achieved in the first embodiment can be similarly achieved in the third embodiment.

  The fracture joint 10 may be formed not only by sewing with a sewing thread, but also by adhesion or sticking with an adhesive or a seal. Moreover, the fracture | rupture joining part 10 should just be formed in at least one side in front view, and may be the left-right direction, an up-down direction, the front-back direction, or the diagonal direction.

  In each of the above-described embodiments, the broken joint portion has been described using the driver's seat airbag, but the passenger's seat airbag deployed from the instrument panel disposed in front of the passenger seat to the passenger side, Curtain airbags that cover the side windows in a curtain shape, side airbags that deploy from the back side of the seat toward the front, knees that deploy between the knees of the passengers in the driver and passenger seats and the instrument panel The present invention can be applied to a break joint portion of an appropriate airbag that needs to be inflated and deployed in a planar shape along a predetermined surface, such as an airbag.

  The present invention can be applied to an airbag apparatus in which a fracture joint is formed in an airbag.

DESCRIPTION OF SYMBOLS 1 ... Airbag apparatus, 2 ... Airbag, 10 ... Breaking junction part, 11 ... Straight section, 12 ... Curved section, 13 ... Folding part, 14 ... Connection section, 16 ... Vent hole, 17 ... Vent hole 18 ... region where vent hole is hidden, 30 ... air bag, 31 ... opening, 32 ... break joint, D ... tangential length, IP ... intersection of tangential length, KA ... clothoid start point, KE ... clothoid end point , L: clothoid curve length, LC: circular curve length, R: radius of curvature at the KE point.

Claims (4)

In an airbag device including an airbag that can be inflated and deployed by gas,
The airbag is formed in a bag shape,
The first base fabric portion and the second base fabric portion that overlap each other in a state where the bag is deflated are joined by a fracture joint portion that breaks at a predetermined deployment pressure at the time of expansion and deployment,
The planar shape of the fracture joint is a linear part having at least one curved folded part,
The airbag device according to claim 1, wherein a predetermined section from the folded portion of the linear portion is formed as a clothoid curve. The clothoid curve has a radius of curvature R, a curve length from the start point of the clothoid curve L, and a clothoid parameter A which is a constant having a dimension of length.
R × L = A ² , R / 3 ≦ A ≦ R
The airbag device according to claim 1, wherein the airbag device is a curve defined by:   The airbag device according to claim 1 or 2, wherein the fracture joint is formed at least in a left-right direction when viewed from the front.   The vent hole formed in the said 1st base fabric or the said 2nd base fabric was formed in the position hidden by the said fracture | rupture junction part from the center of the said airbag, or the position which is not hidden. The airbag apparatus in any one.

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