JP2000006745A - Airbag device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the damaging of an airbag contracted after being expanded by its contact with an inflator heated by high temperature gas. SOLUTION: In an airbag device provided with an inflator 7 for generating gas upon detecting shocks and an airbag 4 unfolded/expanded by the gas generated by the inflator 7, a cooling member 5d having a plurality of cooling fins 5e for absorbing the heat of jetted-out gas is provided in the vicinity of the gas outlet 7a of the inflator 7, high temperature gas jetted out from the gas outlet 7a is rapidly cooled by the cooling fins 5e, and the high temperature of the cooling member 5d or the like is prevented. Thus, the generation of toxic gas caused by the combustion of the airbag 4 is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an airbag apparatus provided with a cooling member near a gas outlet of an inflator.

[0002]

2. Description of the Related Art Conventionally, an airbag device for protecting an occupant from an impact generated by a collision or the like is composed of an inflator which generates gas when an impact is detected, and an airbag which is instantly deployed and inflated by the gas generated from the inflator. Have been.

Further, in the above-mentioned conventional airbag apparatus, since the explosive in the inflator is burned to generate gas, a large amount of heat is generated at the same time as the gas is generated. If an airbag made of a polymer material touches the inflator, the airbag may be damaged.

[0004] In order to improve such a problem, for example, Japanese Patent Publication No. 57-53217 proposes a gas generator in which an airbag is prevented from touching a casing of an inflator.

The gas generator disclosed in the above publication is provided with a tongue-shaped thermal protection plate so as to cover the gas outlet of the inflator.
Even if the inflated airbag contracts, the airbag does not touch the casing of the inflator, which has become hot.

[0006]

However, in the case where the heat protection plate is provided integrally with the casing of the inflator so as to cover the gas ejection port, as in the gas generator disclosed in the above-mentioned publication, when the casing of the inflator becomes high in temperature, the casing becomes inoperable. Because the thermal protection plate attached to
It can be said that the function of dissipating the heat of the generated gas cannot be expected very much.

[0007] Further, since high-temperature and high-pressure gas is generated immediately after the start of combustion of the explosive, the rise of the output characteristic of the inflator gradually changes in a substantially S-shaped curve as shown by a solid line in FIG. Is ideal, but the broken line B
As shown by, it changes with a linear steep gradient.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned conventional problems, and suppresses the temperature of the inflator from becoming high by absorbing the heat of the gas at the initial stage of ignition, and at the same time, makes the rise of the output characteristics of the inflator gentle. It is an object of the present invention to provide an airbag device according to the above.

[0009]

According to the first aspect of the present invention, there is provided an airbag apparatus comprising: an inflator for generating a gas; and an airbag which is deployed and inflated by the gas generated from the inflator. , A cooling member having a plurality of cooling fins for absorbing the heat of the gas ejected separately from the inflator is provided near the gas outlet of the inflator.

According to the above configuration, the high-temperature gas generated from the gas outlet of the inflator is rapidly cooled when it comes into contact with the cooling fins. Therefore, the output characteristic of the inflator is such that the gas pressure gradually increases at the beginning of ignition. Accordingly, the impact when the airbag comes into contact with the occupant can be reduced.

In order to achieve the above object, according to a second aspect of the present invention, a cooling member is formed integrally with a base plate to which an inflator is attached.

With the above structure, the heat of the high-temperature gas absorbed by the cooling fins is radiated from the surface of the base plate, the surface of the reinforcing rib provided on the back surface of the base plate, the surface of the inflator attached to the base plate, and the like. The temperature of the base plate of the cooling member does not become high, so that even if the airbag contracted after inflation touches the cooling member or the base plate, it is possible to prevent the airbag from being damaged.

In order to achieve the above object, according to a third aspect of the present invention, each cooling fin of the cooling member has a predetermined inclination angle with respect to a gas jetting direction.

According to the above configuration, since the turbulence in the gas flow is reduced, the heat in the high-temperature gas can be efficiently absorbed.

[0015]

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

FIG. 1 is a front view of a steering wheel provided with an airbag device, FIG. 2 is an exploded perspective view of the airbag device, FIG. 3 is a cross-sectional view of an assembled state of the airbag device,
4 is an upper perspective view of the base plate, FIG. 5 is a lower perspective view of the same, and FIG. 6 is an operation explanatory view.

In FIG. 1, 1 is a steering wheel 2
The main body of the airbag device installed near the center of FIG.
, A cover 2a covering the upper surface, a retainer 3,
It comprises an airbag 4, a base plate 5, a belt 6, and an inflator 7, and is assembled as shown in FIG.

That is, the base plate 5 fixed in the steering wheel 2 is formed by integrally molding a metal having high thermal conductivity, for example, aluminum or magnesium by die casting, and has a substantially square flat plate portion 5a. A circular inflator insertion hole 5b is opened at the center of the flat plate portion 5a.

Around the inflator insertion hole 5b,
A plurality of small holes 5c into which mounting screws 3a protruding from the lower surface of the retainer 3 are inserted from above are opened, and a cooling member 5d is formed integrally with the flat plate portion 5a above the inflator insertion hole 5b. I have.

The cooling member 5d cools the high-temperature gas jetted from the gas jet port 7a of the inflator 7, and has a frusto-conical shape in which the upper end side gradually becomes smaller in diameter.
A large number of cooling fins 5e are formed in a vertical direction inside the peripheral surface portion.

The fins 5e have a substantially triangular shape and have a rectifying function for cooling the high-temperature gas jetted from the gas jet port 7a of the inflator 7 and for adjusting the jet direction of the gas at the same time. As shown in FIG. 6, a predetermined inclination angle is provided in the radial direction, and a notch 5f is formed on the lower side so as not to interfere with the inflator 7.

There are long and narrow gaps between the fins 5e, and gas is blown into the airbag 4 from these gaps. Support 5g for increasing rigidity of member 5d
Are provided in the longitudinal direction at intervals in the circumferential direction.

On the other hand, the airbag 4 folded as shown in FIG. 3 is housed on the base plate 5, and the periphery of the opening 4 a opened on the bottom surface of the airbag 4 extends from the inside of the airbag 4. The mounting screw 3a, which is airtightly sandwiched between the retainer 3 attached to the upper surface of the base plate 5 and the base plate 5 and protrudes from the lower surface of the retainer 3, moves downward from the small hole 5c of the base plate 5 to below the base plate 5. It is protruding.

An inflator 7 having a gas outlet 7a inserted into these mounting screws 3a from the lower surface of the base plate 5 into an inflator insertion hole 5b of the base plate 5.
The inflator 7 is fixed to the lower surface of the base plate 5 by inserting the mounting hole 7b and tightening the nut 3b.

A band 6 is provided on the peripheral surface of the base plate 5.
The cover 2a covers the upper portion of the airbag 4 by fitting a mounting portion 2b projecting from the inside of the cover 2a to the band 6.

Next, the operation of the airbag device configured as described above will be described.

When a running vehicle generates an impact due to a collision or the like, a collision detection sensor (not shown) detects the impact and ignites the explosive in the inflator 7.

As a result, the explosive is burned to generate high-temperature gas, which is ejected from the gas ejection port 7a.

The high-temperature gas impinges on the cooling fins 5e of the cooling member 5d and is released into the airbag 4 from the gaps between the cooling fins 5e while being rectified as shown by arrows in FIG. Instantly expands and expands,
The hot gas in the initial stage of ignition is rapidly cooled by the cooling fins 5e when it comes into contact with the plurality of cooling fins 5e of the cooling member 5d made of a metal having a high thermal conductivity.

As a result, the output characteristic of the inflator 7 after ignition gradually rises at the beginning of ignition as shown by the solid line A in FIG.
Reaches a predetermined pressure when restraining the occupant.

That is, since the gas pressure in the airbag 4 rises while drawing an ideal S-shaped curve, the impact when the airbag 4 comes into contact with the occupant can be reduced.

The heat of the high-temperature gas absorbed by the cooling fins 5e is transmitted from the cooling fins 5e to the flat plate portion 5a, and lattice-like reinforcing ribs provided on the front surface of the flat plate portion 5a and the back surface of the flat plate portion 5a. Since the surface 5h and the surface of the inflator 7 attached to the base plate 5 dissipate heat, the base plate 5 and the cooling member 5d do not become hot, so that the inflated and contracted airbag 4 is removed from the base plate 5 and the cooling member 5d. , There is no fear that the airbag 4 is damaged.

The grid-like reinforcing ribs 5h provided on the back surface of the base plate 5 are for increasing the strength of the base plate 5, but also function as a heat sink, so that a high heat dissipation effect can be obtained and the reinforcing ribs 5h can be obtained. Even if 5 g is pin-shaped, the same heat radiation effect can be obtained.

In the above embodiment, the cooling member 5d is provided integrally with the base plate 5, but the same effect can be obtained by providing the cooling member 5d integrally with the retainer 3 as shown in FIG.

[0035]

According to the present invention, as described in detail above, a cooling member having a plurality of cooling fins for absorbing the heat of the high-temperature gas ejected separately from the inflator is provided near the gas outlet of the inflator. Since the high-temperature gas jetted from the gas jet port is cooled by the cooling member, an output characteristic in which the gas pressure gradually increases at the initial stage of ignition of the inflator can be obtained. The impact when contacting the bag can be reduced, and the heat of the hot gas absorbed by the cooling fins is
Transmitted to the base plate,
Since heat is radiated from the reinforcing ribs on the back surface, the surface of the inflator attached to the base plate, and the like, the temperature of the inflator of the cooling member does not become high.

As a result, there is no fear that the airbag contracted after inflation will be damaged even if it touches the cooling member or the base plate.

Further, by providing the cooling fins of the cooling member with an inclination angle with respect to the gas ejection direction of the inflator in advance, the high-temperature gas is rectified and deflected by the cooling fins,
The heat of the high-temperature gas can be efficiently absorbed, so that the high-temperature gas can be cooled in a short time.

[Brief description of the drawings]

FIG. 1 is a front view of a steering wheel provided with an airbag device according to an embodiment of the present invention.

FIG. 2 is an exploded perspective view of the airbag device according to the embodiment of the present invention.

FIG. 3 is a sectional view showing an assembled state of the airbag device according to the embodiment of the present invention.

FIG. 4 is a top perspective view of a base plate constituting the airbag device according to the embodiment of the present invention.

FIG. 5 is a bottom perspective view of a base plate constituting the airbag device according to the embodiment of the present invention.

FIG. 6 is an operation explanatory view of the airbag device according to the embodiment of the present invention.

FIG. 7 is a diagram showing output characteristics of an inflator used in the airbag device according to the embodiment of the present invention.

FIG. 8 is an explanatory view showing a modification of a cooling member provided in the airbag device according to the embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Airbag apparatus main body 2 Steering wheel 2a Cover 2b Mounting part 3 Retainer 3a Mounting screw 3b Nut 4 Airbag 4a Opening 5 Base plate 5a Flat plate part 5b Inflator insertion hole 5c Small hole 5d Cooling member 5e Cooling fin 5f Notch 5g Post 5h Reinforcing rib 6 Band 7 Inflator 7a Gas outlet 7b Mounting hole

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Tetsuji Endo 218 Aoshima-cho, Fuji-shi, Shizuoka Prefecture, Japan Plast Co., Ltd. Terms (reference) 3D054 AA02 AA03 AA07 AA13 BB04 BB26 BB30 CC43 CC47 DD19

Claims (3)

[Claims] 1. An airbag apparatus comprising an inflator for generating gas and an airbag which is deployed and inflated by the gas generated from the inflator, wherein the airbag is ejected separately from the inflator in the vicinity of the gas outlet of the inflator. An airbag device comprising: a cooling member having a plurality of cooling fins for absorbing heat of the gas. 2. The airbag device according to claim 1, wherein the cooling member is formed integrally with a base plate to which the inflator is attached. 3. The airbag device according to claim 1, wherein each cooling fin of the cooling member has a predetermined inclination angle with respect to a gas ejection direction.