JPH0544714U - Casing structure for inflatable occupant restraint system - Google Patents

Abstract

(57) [Summary] (Correction) [Purpose] To develop a casing of an inflatable occupant restraint device that accommodates an inflating airbag, which can be easily broken to instantly inflate the airbag. [Structure] A stress concentrating portion is provided in the casing 2,
The casing should break from the groove 12b even if a little stress is applied.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a casing for an inflatable occupant restraint system, and more particularly to a casing for a passenger when a vehicle collides with a vehicle or suddenly stops, or when the occupant hits a structure in the passenger compartment, or if the passenger has a window, in a significant case. The present invention relates to the structure of a casing used in an inflatable occupant restraint system to prevent the vehicle from being torn and thrown out of the vehicle.

[0002]

[Prior Art]

 As is well known, the damage to the occupant during a vehicle collision is caused by the primary impact that is received by a road structure or another vehicle, and the secondary impact that the occupant is impacted by a structure in the passenger compartment. There is. A so-called airbag device, which is instantly inflated by gas pressure in order to prevent this secondary collision and reduce the impact on the occupant, is proposed, for example, in US Pat. No. 4,148,503. Has been done.

By the way, the casing for accommodating the above-mentioned airbag device needs to be able to withstand a slight impact from the outside without hindering the rapid expansion of the bag body. Generally, this casing is made of relatively hard urethane resin, etc., but in order to make it easy to break according to the internal pressure of the case due to the expansion of the bag, The continuous grooves are recessed so as to face each other, thereby forming a continuous thin portion.

As for the thin portion formed by the groove formation, the following has been conventionally proposed. One of them is a groove that forms a thin portion, and has a considerable width, and has a large width so that the casing can be broken without resistance due to the expansion of the bag body. However, in this case, the fracture line becomes indeterminate, and the fracture may easily occur indefinitely.

The other one is to eliminate the drawbacks of the above, and is proposed by Japanese Utility Model Laid-Open No. 63-201862. This is designed so that when the airbag is inflated, it breaks along a predetermined breaking line, and this breaking line consists of thin-walled parts formed by grooves recessed on both the front and back sides of the casing, In addition, the center lines of both grooves are offset from each other.

[0006] However, this method is intended to clarify the breaking line and stabilize the breaking, and although the easiness of breaking is considerably improved, the edge of the square groove on the surface side is improved. Stress tends to concentrate at the edges, and break lines tend to appear clearly at the edges, but the groove shape on the back side is mountain-shaped, and since the apex is a rounded shape, the stress concentration point cannot be specified. However, due to this, the fracture line was small and bent in a zigzag shape, which was still insufficient. Further, in the conventional example, it is necessary to form an extremely thin portion for easy breakage, but there is a problem that the cover bends or the color changes at this thin portion. Therefore, the present invention forms an edge portion of a groove in which stress is likely to concentrate on the back surface side without forming an extremely thin portion as in the conventional example to facilitate breakage, and to break the edge between both surfaces. It is intended to clarify the fracture line by forming it so as to connect the parts.

[0007]

[Problems to be solved by the device]

 The problem to be solved by the present invention is to provide a casing of an inflatable occupant restraint system that is extremely easy to break and has a stable breaking line.

[0008]

[Means for Solving the Problems]

 This problem is related to the casing of an inflatable occupant restraint system, which is configured to fold and store an airbag that is instantly inflated by gas pressure, and to break at a predetermined location when the airbag is inflated. The breaking point can be solved by adopting a structure including a stress concentrating portion formed between the edge portions of the grooves recessed on the front and back surfaces of the casing.

[0009]

[Operation and configuration of the device]

 If this is done, stress concentrates on the edges of the groove, so it is extremely easy to break.If the edges of the groove on the front and back sides are placed close to each other, the break will be a shape that connects both edges, and the break line Will be stable. Also, if the shape of the edge part is made more acute, the stress concentration effect is enhanced and the fracture becomes easier.

[0010]

【Example】

 The present invention will be described in detail below with reference to the drawings.

[0011]

Embodiment 1 FIGS. 1 and 2 show a steering wheel equipped with an airbag device to which the present invention is applied.

The casing 2 of the airbag device 1 is formed as a center pad of the steering wheel 3, and is supported by a bracket 5 integrally fixed to a core metal 4 of a spoke via a stay 6. ..

The airbag device 1 housed in the casing 2 includes a bag body 7 as a nylon airbag having an inner wall coated with rubber, and an inflator 8 joined to an opening of the bag body 7. It consists of

The inflator 8 is composed of an ignition device 9 provided in the center and a gas generating agent 10 arranged on the outer periphery of the inflator 8, and the gas generating agent 10 is separately supplied by a signal from a collision detection device (not shown). The bag body 7 folded inside the casing 2 is instantly inflated by burning a large amount of gas generated by the combustion.

The casing 2 is substantially box-shaped, is made of a relatively hard resin, and is reinforced by a synthetic resin fiber core material 11 having a relatively high tensile strength. As shown in FIG. 1, on the front surface 2a of the casing 2, horizontal grooves 12a and 12b are provided in the upper and lower and central portions along the horizontal direction, and vertical grooves 12c are provided in the left and right portions along the vertical direction. ing. Then, the core material 11 is divided along the lateral groove 12b and the vertical groove 12c in the central portion as shown by the broken line in FIG. 1, and the inside of the side wall 2b of the casing 2 as shown in FIG. The end portion of the anchor 13 is connected to the anchor 13 connected to the stay 6.

As shown in FIG. 3, the horizontal groove 12b and the vertical groove 12C in the central portion form a substantially rectangular cross section, and the edge portion 18 of this groove and the groove 14 provided on the back surface side of this groove are A stress concentration part is formed at 17 together with the edge part 19, and this part is the weakest part. The portion of the lateral groove 12a is formed to be slightly thinner than the peripheral portion in order to bend without breaking at this portion.

When the bag body 7 expands from the inside of the casing 2 when a collision is detected, it breaks at the stress concentrating portion 17 formed by the edges 18 and 19 of the grooves 12b, 12c and 14 on the front and back surfaces. , In particular, at this time, if part of the fracture occurs due to the stress concentration effect, the fracture progresses continuously from this fracture point, and due to the notch effect, the fracture progresses smoothly along the edge portion in the form of connecting the edge portions. As a result, the casing can be easily fractured, and the fracture line is also stable in line with the edge. On the other hand, since the core material 11 is provided inside the upper and lower lateral grooves 12a of the front surface 2a, as shown by an imaginary line in FIG. The front surface 2a of the thing 2 is designed not to fall off from the side wall 2b. Although the drawing shows the case in which the core material 11 is disposed inside the casing 2, the present invention can be applied to a type in which the core material 11 is not disposed, for example, a casing of a thermoplastic elastomer. Needless to say,

[0018]

Embodiments 2 to 6 Various shapes can be considered for the stress concentration portion of the thin portion formed by the lateral groove 12 and the groove 14 in Embodiment 1 as shown in FIGS. In particular, since a bending moment load and a tensile load in the direction in which the casing bulges outward act simultaneously at the casing rupture portion, an acute groove edge with a high stress concentration effect was formed on the casing outer surface side. The example of No. 8 is the shape that is most easily broken. Other examples are also desirable forms of the present invention, and like the first embodiment, stress concentrates and breaks easily.

[0019]

[Effect of the device]

 As described above, according to the present invention, the edge portion of the groove can be extremely easily fractured by the stress concentration effect, and the fracture line is also stabilized by the notch effect, and the effect is extremely large.

[0020]

[Brief description of drawings]

[0021]

FIG. 1 is a partial front view of a steering wheel to which the present invention is applied.

[0022]

FIG. 2 is a sectional view taken along line II-II in FIG.

[0023]

FIG. 3 is an enlarged sectional view of a main part taken along the line III-III in FIG.

[0024]

FIG. 4 is an enlarged sectional view of an essential part showing another example of FIG.

[0025]

FIG. 5 is an enlarged cross-sectional view of main parts showing another example of FIG.

[0026]

FIG. 6 is an enlarged cross-sectional view of a main part showing another example of FIG.

[0027]

FIG. 7 is an enlarged cross-sectional view of an essential part showing another example of FIG.

[0028]

FIG. 8 is an enlarged cross-sectional view of an essential part showing another example of FIG. 1 ……………… Airbag device 2 ………… Casing 2a ………… Front face 2b …… Sidewall 3 ……………… Steering wheel 4 ……………… Core bar 5 ………… Bracket 6 ………… … Stay 7 ………… Bag body 8 ……………… Inflator 9 ………… Ignition device 10 ………… Gas generating agent 11 …… Core material 12a, 12b… Horizontal groove 12c… Vertical groove 13 ………… Anchor 14 ...... Groove on back side 17 ...... Stress concentration area 18 ...... Edge area 19 ............ Edge area

Claims (1)

[Scope of utility model registration request] In the casing of the inflatable occupant restraint system, which is configured to fold and store an airbag adapted to be instantly inflated by gas pressure, and to be ruptured at a predetermined position when the airbag is inflated, A casing structure for an inflatable occupant restraint system, characterized in that it comprises stress concentration portions formed between edge portions of grooves formed on both front and back surfaces of the casing.