JP3114258B2 - Inflator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inflator for supplying an inflation gas to an airbag in an automobile airbag apparatus.

[0002]

2. Description of the Related Art An airbag device for an automobile is composed of a collision detection device, an inflator for generating gas for inflating the airbag, and an airbag.
The airbag is inflated to absorb the impact on the driver and the occupant.

As shown in FIG. 5, a conventional inflator includes a gas generating agent 23 made of a mixture of an alkali metal azide and a metal oxide, and a igniter 24 in a case 21 having a gas discharging hole 22 formed in an outer wall. The ignition device 24 is composed of an ignition agent 25 and an igniter 26 that is activated by a signal from the impact detection device. In this structure, the ignition agent 25 is ignited by the igniter 26, and the gas generating agent 23 is burned by the thermal energy to instantaneously generate N ₂ gas.
The gas is introduced into the airbag through the gas discharge hole.

[0004]

The gas generating agent 23 using an alkali metal azide is 4NaN ₃ + O _2.
→ Nitrogen gas is generated by the reaction formula of 2Na ₂ O + 6N ₂ , but Na ₂ O as a by-product has extremely harmful properties to the human body. However, after the airbag is inflated,
Since it is necessary to gradually contract for shock absorption and escape, a gas escape hole is provided to allow excess gas to escape, but if harmful components are introduced into such a bag, it will pass through the hole. There was a problem that harmful components appeared and harmed the human body.

[0005] In the conventional airbag device, an explosive substance such as an explosive is used as the ignition agent 25 in order to burn the gas generating agent instantaneously. There is a problem in the safety of the assembling work etc. due to the danger of handling. In addition, there is a risk that anyone can obtain explosive substances when mounted on a car, and there is a problem in its protection.

The present invention has been made in view of the above problems, and a first object of the present invention is to provide an inflator capable of generating a large amount of gas containing no harmful components.

Another object of the present invention is to provide an inflator that can generate gas without using explosive substances.

[0008]

SUMMARY OF THE INVENTION In order to achieve the first object, the present invention provides a storage unit for a combustible substance generating a combustion gas, and a means for heating the combustible substance having an oxygen supply source. And a structure having:

As the flammable substance, volatile light petroleum can be used.

[0010]

Further , as the oxygen supply source, a thermally decomposable oxygen generator disposed around the heating means can be used.

[0012] The upper SL heating means, can also be achieved power and construction Then the second object from the heating element which generates heat by energization
You.

As the above power source, an electric double layer capacitor can be used.

[0014]

The detection signal of the action] shock, actuates the heating means flammable material and heated, thereby generating combustion gases.

The combustion gas of such a combustible substance is CO
₂ and H ₂ O, which do not contain harmful components and do not harm the human body even if they leak to the outside.

As the flammable substance, a substance which is easily flammable is used. In particular, when a highly volatile light petroleum product such as gasoline is used, the flammable substance can be easily ignited at a low heating temperature without a high-temperature generator. Since a large amount of gas is generated by combustion, the airbag can be inflated in a short time.

Further, during heating , the combustible material can be efficiently burned by actively supplying oxygen from the oxygen supply source by the heating means, and a large amount of gas can be generated in a short time.

In this case, if a thermally decomposable oxygen generating agent is arranged around the heating means as an oxygen supply source,
Since active oxygen can be generated around the heating section together with the heat generated by the heating means, the mixing property between the combustible substance and oxygen is improved, and the combustion efficiency can be greatly improved.

The heating means is energized heating element to generate heat by the power source, it is intended to heat the combustible material by Joule heat generated.

In such a structure in which heat is generated by energization, there is no danger as in the case of using an explosive substance, and since the heat generating element can generate heat instantaneously by the operation of a switch or the like, it has good responsiveness. Gas generation can be performed. Further, since the amount of heat generated can be changed depending on the magnitude of the current to be supplied, there is an advantage that the amount of gas to be generated can be easily controlled.

As the above-mentioned power source, a normal power source such as a battery or a capacitor can be used. However, if an electric double-layer capacitor is used, a large amount of electricity can be stored in a lightweight and compact shape, and the inflator can be used. Can be reduced in size.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment will be described below with reference to the accompanying drawings.

As shown in FIG. 1, the airbag device 1 comprises:
The inflator 2 and the airbag 3 are connected by a communication pipe 4, and a filter 5 for removing fine dust and the like in the gas is housed inside the communication pipe 4.

As shown in FIGS. 2 and 3, the inside of the inflator 2 is vertically partitioned by a thin metal film 6, and the upper portion of the metal film 6 is used as a storage section 8 for a flammable substance 7. Below the metal film 6, a heater 12 including a heating element 10 in which a plurality of metal wires 9 are arranged in parallel and a power supply circuit 11 are arranged. The powder of the oxygen generator 13 is filled.

The power supply circuit 11 comprises an electric double-layer capacitor 14 and a switch 15 which is activated by a signal from an impact detector (not shown) for detecting a pressure change or the like at the time of a collision. The metal wire 9 and the metal film 6 of the heating element 10 are connected in parallel.

The airbag device 1 having the above structure
In the above, when the switch 15 is turned on and a current flows from the capacitor 14 to the metal film 9 and the heating element 10, the heating element 10 generates heat and the oxygen generator 13 is thermally decomposed to generate active oxygen. 6 is melted and the combustible substance 7 falls onto the heating element 10. Therefore, the combustible substance 7 is heated by the heating element 10 and instantly burns by the generated oxygen to generate gas, and the gas flows into the airbag 3 to inflate the bag.

(Experimental Example) Next, a bag inflation experiment performed by using the above-described apparatus will be described. In the experiment, the content of the airbag 3 was set to 30 liters,
Stored 40 g of gasoline as the flammable substance 7. In addition, 660 g of Cu
O powder and the heating element 1 by the CuO powder
0 was entirely covered.

The metal film 6 is made of aluminum foil having a thickness of 2 μm, and the five metal wires 9 forming the heating element 10 are formed.
An aluminum wire having a wire diameter of 60 μm and a length of 40 μm was used.

After making the above preparations, the electric double-layer capacitor 1
4, a current of 2 A was set to flow through the metal film and a current of 1 A was set to flow through each metal wire 9 of the heating element 10.

By the operation of the switch 15, the metal wire 9 of the heating element 10 generates heat almost immediately, oxygen is instantaneously generated from the CuO powder in contact with the metal wire 9, and the metal film 6 is melted almost simultaneously, Dropped on the heating element 10 and ignited instantaneously. The combustion gas of the gasoline 7 was introduced into the airbag 3 through the communication pipe 4, and rapidly inflated the bag.

FIG. 4 shows the pressure change in the airbag in this inflation test.
３30 msec, the bag 3 shows the maximum internal pressure, 60 m
It expanded to a complete developed shape around sec.

When the gas inside the inflated airbag 3 was analyzed, most of the gas was CO ₂ , and no harmful components were contained.

Although gasoline is used as the flammable substance 7 in the above experimental example, other highly volatile petroleum products may be used.

The mixing of the combustible substance and oxygen is not limited to the above-described method. For example, an oxygen cylinder containing active oxygen is connected to an inflator via an on-off valve to heat the heating element. At the same time, the deployment valve may be opened to introduce oxygen.

[0035]

[Effect] As described above, Oite to the inventions is, subjected to oxygen
Gas is generated by burning flammable substances while supplying gas, so a large amount of gas harmless to the human body is generated in a short time.
As a result, the airbag can be inflated, and a safe airbag device can be realized.

Further, heats the combustible material by heat by passing electricity, there is no danger as in the case of burning explosive substances such as explosives, it can provide an excellent apparatus in safety.

[Brief description of the drawings]

FIG. 1 is a front view showing an airbag device of an embodiment.

FIG. 2 is a longitudinal sectional front view showing the internal structure of the above-described inflator.

FIG. 3 is a sectional view taken along the line III-III in FIG. 2;

FIG. 4 is a graph showing changes in the internal pressure of the airbag.

FIG. 5 is a perspective view showing the internal structure of a conventional inflator.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 airbag device 2 inflator 3 airbag 6 metal film 7 flammable substance 8 storage unit 10 heating element 11 power supply circuit 12 heater 13 oxygen generator 14 electric double layer capacitor

────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yoshihiro Nakai 1-3-1 Shimaya, Konohana-ku, Osaka Sumitomo Electric Industries, Ltd. Osaka Works (56) References JP-A-61-235247 (JP, A) Kaihei 3-79451 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B60R 21/16-21/32 B01J 7/00

Claims (5)

(57) [Claims] 1. An inflator comprising: a storage section for a combustible substance that generates a combustion gas; and heating means for the combustible substance having an oxygen supply source . 2. The inflator according to claim 1, wherein the oxygen supply source is a thermally decomposable oxygen generator disposed around a heating unit. 3. The inflator according to claim 1, wherein the combustible substance is volatile light petroleum. 4. The inflator according to claim 1, wherein said heating means comprises a power source and a heating element that generates heat when energized. 5. The inflator according to claim 4, wherein said power supply is an electric double-layer capacitor.