JP2598813B2 - Combustion chamber of gas generator for airbag deployment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an airbag deployment used for deploying an airbag such as an air bag, a lifesaving bag, a rubber boat, and an escape chute for a collision safety device by using gas. The present invention relates to a gas generating device for a vehicle, and particularly to a structure of a combustion chamber thereof.

[Conventional technology]

Conventionally, in a passenger car, a collision safety device for protecting a driver from a shock at the time of the collision includes, for example, an airbag having a volume of 60 liters and an airbag deployment gas for deploying the airbag with gas. When a passenger car collides, a gas generating agent composed of explosives or a similar composition filled in the air bag deploying gas generating device is ignited and burned, and the air bag is generated by the generated gas. It deploys instantaneously to protect the driver from collisions and prevent serious injury to the driver.

FIG. 8 shows a conventional gas generator for deploying an air bag disclosed in Japanese Patent Application Laid-Open No. 55-110652, wherein reference numeral 11 denotes a large number of pellet-shaped gas generating agents 13. 2 shows a combustion chamber.

In the center of the combustion chamber 11, an igniter 15 and an ignition charge 17 for burning the gas generating agent 13 are arranged.
A combustion chamber filter 19 is arranged along the inner periphery of the combustion chamber 11.

A charge chamber 21 that surrounds the combustion chamber 11 and in which the gas that has passed through the combustion chamber filter 19 flows is arranged in an annular shape.

In the charging chamber 21, a charging chamber filter 23 is accommodated, and in the charging chamber 21, a charging chamber filter 23 is provided.
A gas outlet 25 for discharging the gas passing through the airbag to the airbag is provided.

In such a gas generator for airbag deployment, when electricity is supplied to the igniter 15, the igniting agent 17 burns, and the combustion causes the gas generating agent 13 to burn. After flowing through the combustion chamber filter 19 disposed along the inner periphery of the combustion chamber 11 and flowing into the charging chamber 21, it is purified by the charging chamber filter 23 and flows into the airbag through the gas outlet 25. Then, for example, the airbag is sufficiently inflated in a short time of about 0.04 seconds.

[Problems to be solved by the invention]

However, in such a conventional gas generator for deploying an air bag, since the combustion chamber 11 is filled with a large number of granules or a pellet-shaped gas generating agent 13,
The porosity is very large, and as a result, the volume of the combustion chamber 11 becomes large, and there is a problem that it is very difficult to reduce the size of the airbag deployment gas generator.

That is, for example, in a gas generator for deploying an airbag incorporated in a steering wheel of an automobile, it has been strongly demanded to reduce the size of the gas generator for deploying an airbag in order to improve the incorporation and appearance. However, it was very difficult to reduce the size for such a reason.

An object of the present invention is to solve the above-described problems and to provide a combustion chamber of a gas generator for deploying an air bag that can significantly reduce the volume of the combustion chamber as compared with the related art.

[Means for solving the problem]

The combustion chamber of the gas generator for airbag deployment of the present invention,
In the combustion chamber of the gas generator for deploying an air bag in which an igniter and an igniting agent are arranged adjacent to each other in the center and a plurality of gas generating agents are arranged outside the igniter and the igniting agent, the gas generating agents penetrate to the center While being formed in an annular plate shape forming a hole, a chamfered portion is formed on the outer periphery and the through hole,
Each of these gas generating agents is laminated on the entire surface except for the chamfered portion via the annular wire mesh separator, and is filled with an igniting agent in the space formed by each central through-hole, and is surrounded by a sealed container. It is characterized by having.

(Operation)

In the combustion chamber of the airbag deployment gas generator of the present invention, the annular wire mesh separator is arranged on the entire surface of the overlapping surface between the gas generating agents except for the chamfered portion of the gas generating agent to be laminated. Particularly, since the gas generating agent is sandwiched between the annular wire mesh separators, stable combustion can be maintained even when the surface area of the gas generating agent changes due to combustion, and a combustion passage can be secured.

Further, since the annular wire mesh separator has a wire mesh shape, the flow of the combustion gas is emphasized in different directions such as a horizontal direction and a vertical direction, whereby the heat particles are dispersed and the combustion ignition is performed smoothly.

Further, since the wire mesh is used, the combustion gas can be cooled and the combustion residue can be removed.

Next, with respect to the chamfered portion, ignition from the igniting agent can be performed efficiently, and combustion can be improved.

In addition, since the igniting agent is disposed in the central through hole of the gas generating agent to be laminated and accommodated in a sealed container, the ignition of the gas generating agent can be reliably performed by the ignition from the igniter together with the moisture proof effect.

〔Example〕

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

1 and 2 show details of a gas generating agent of the gas generator for developing an air bag shown in FIG. 3, and FIG. 3 shows a combustion chamber of the gas generating device for developing an air bag of the present invention. 1 shows an airbag deployment gas generator with one embodiment.

In FIG. 3, reference numeral 41 denotes a combustion chamber in which the gas generating agent 43 is stored.

In the center of the combustion chamber 41, an igniter 45 and an ignition charge 47 for burning the gas generating agent 43 are arranged.
A combustion chamber filter 49 is arranged along the inner periphery of the combustion chamber 41.

A charge chamber 51 surrounding the combustion chamber 41 and into which gas that has passed through the combustion chamber filter 49 flows is arranged in an annular shape.

In the charging chamber 51, a charging chamber filter including the filter 53 and the gas filtration filter 55 is accommodated. Further, in the charging chamber 51, a gas outlet 57 for discharging the gas that has passed through the gas filtration filter 55 to the airbag is disposed.

In this embodiment, the combustion chamber 41 is
It is formed by a bottomed cylindrical portion 61 of 59 and a lid member 65 that is electron beam welded 63 to this opening.

As shown in FIGS. 4 and 5, the housing body 59 has a bottomed cylindrical portion 61 and a flange portion 67 integrally formed outwardly with an opening of the bottomed cylindrical portion 61. From the outer periphery of the flange portion 67 to the bottom portion 69 of the housing body 59.
And an outer cylindrical portion 71 bent toward the side.

A second flange portion 73 is formed integrally at the tip of the outer cylindrical portion 71 toward the outside.
A mounting hole 75 for mounting an airbag is formed.

Then, as shown in FIG. 3, the charging chamber 51 covers the outer cylindrical portion 71 and the bottomed cylindrical portion 61 of the housing main body 59 from the bottom surface portion 69 side of the housing main body 59 with the covering member 77, The cover member 77 is formed by welding and joining to the outer tubular portion 71 and the bottomed tubular portion 61 by welding 79, 80 such as an electron beam or a laser beam.

In this embodiment, as shown in FIG. 6, the covering member 77 has an L-shaped cross section, and one end is inserted into the inside of the outer cylindrical portion 71 of the housing body 59, and the other end is inserted. The inner periphery of the bent portion 81 formed on the housing body 59 is in contact with the outer periphery of the bottomed cylindrical portion 61 of the housing body 59.

The bottomed cylindrical portion 61 of the housing body 59 is formed with a predetermined angle, for example, 18 orifices 82 are formed, and the covering member 77 is formed with a predetermined angle, for example. , 18 gas outlets 57 are formed.

Further, in this embodiment, the housing body 59, the lid member 65
The cover member 77 is formed of stainless steel.

Thus, in this embodiment, 5-6 gas generating agents are provided outside the igniter 45 and the igniter 47 in the combustion chamber 41.
43 are arranged, and in this embodiment, each gas generating agent 43 is provided.
As shown in FIG. 1 and FIG.
Is formed in the shape of an annular plate.

And each gas generating agent 43, in order to improve the ignitability,
Arc-shaped chamfers on the inner and outer circumferences of the gas generating agent 43
46 are formed with a flat shape between them.

The gas generating agent 43 is, for example,
It contains 28% by weight of iron oxide, 28% by weight of iron oxide, 8% by weight of potassium perchlorate, and 2% by weight of solder glass. For example, 18 grams of granules having these compositions are weighed and formed into an annular mold. Fill and press mold with pressure of 40-60 tons.

These gas generating agents 43 are stacked, and an igniter 45 and an igniter 47 are arranged in a through hole formed in the center.

Further, a separator 83 is arranged between the gas generating agents 43.

These separators 83 are, for example, stainless steel 10
It is made of an annular wire mesh using # 50 wire, which improves the ignitability of the gas generating agent 43 and enables the gas generating agent 43 to have an exhaust passage.

In this embodiment, these gas generating agent 43, separator 8
3. The igniting agent 47 and the combustion chamber filter 49 are surrounded by a sealed container 85 in order to prevent the gas generating agent 43 and the igniting agent 47 from absorbing moisture.

This sealed container 85 is made of flame-retardant thermoplastic,
For example, polypropylene, nylon with glass fiber, polycarbonate, polyacetal, polysulfone, polyethylene terephthalate, etc. and flame-retardant thermosetting resin,
For example, it is made of epoxy, phenolic resin, polyphenyl sulfide or aluminum.
Sealed by ultrasonic bonding or hot melt welding in the state of being inserted into 87. In this case, the aluminum is sealed by winding, bonding or electron beam welding.

At the center of the upper lid 86 of the sealed container 85, a concave portion 88 which is depressed toward the through hole of the gas generating agent 43 and accommodates the igniter 45 is formed.

The center of the gas generating agent 43 is filled with an igniting agent 47. In this embodiment, the igniting agent 47 is obtained by coagulating magnesium and ethylene tetrafluoride with a binder of ethylene trifluoride chloride. Is formed.

The igniting powder 47 is, for example, 60% by weight of magnesium and 40% by weight of ethylene tetrafluoride.
It is a flocculent igniting agent composed of 5% by weight. For example, when 1.1 g of an igniting agent is used, a calorific value is 1940 calories / g, a gas generation amount is 41 cc / g, and a conventional boron-potassium nitrate igniting agent is used. Compared to a calorific value of 1790 calories / g and a gas generation amount of 79cc / g, the heat generation amount is high and the gas generation amount is low.
43 can be obtained without cracking and with no time delay.

The ignition charge 47 is manufactured as described below.

That is, for example, in order to obtain an ignition agent 47 having a weight of 300 g, 180 g of magnesium was put into 14.2 g of ethylene trifluoride dissolved in toluene, and this magnesium was sufficiently wetted. Fluoroethylene 12
Add 0 g and mix, then pass through a 12-mesh sieve 5 times to dry, and after this drying, stir with a mixer to obtain a flocculent ignition powder.

FIG. 7 is a graph comparing the combustion pressure of the combustion chamber 41 in the case of using the ignition agent 47 described above and the ignition agent obtained by mixing conventionally used metal boron and potassium nitrate.

That is, the vertical axis of the figure indicates the combustion chamber when the same gas generating agent 43 is burned in the combustion chamber 41 using the respective igniting agents.
It shows a pressure of 41, and from this figure, the pressure due to the B + KNO ₃ igniting agent is 218 kg / cm ² , and it burns with an igniting agent 47 composed of magnesium, ethylene tetrafluoride and ethylene trifluoride chloride (Mg-Te). The pressure at this time is 130 kg / cm ² .

This is because the B + KNO ₃ igniting agent generates a large amount of igniting agent gas and has a high initial pressure at the time of ignition, so that the gas generating agent 43 is broken, thereby increasing the combustion pressure and shortening the combustion time. ing.

On the other hand, in the case of the ignition powder 47 made of Mg-Te, the waveform has a low pressure, and a normal combustion pressure waveform without cracks can be obtained.

That is, in this embodiment, since the gas generating agent 43 has a ring shape, if the same ignition method as that of the conventional air bag developing gas generating device shown in FIG.
Is destroyed, it is easy to cause abnormal combustion, and even when it does not lead to destruction, the ignitability varied, but in this example, magnesium was directly coagulated with Teflon at the center of the gas generating agent 43. Since the formed ignition charge 47 is filled, the risk of destruction of the gas generating agent 43 can be reliably eliminated.

A combustion chamber filter (first filter) 49 is arranged in the sealed container 85 so as to surround the gas generating agent 43.

This combustion chamber filter 49 has a mesh size of 10
It is configured by winding a stainless steel mesh of No. 35 to around a gas generating agent, and has the following functions.

A function of lowering the combustion gas temperature of the gas generating agent 43 and facilitating capture of combustion products by a filter.

A function that acts as a buffer against vibration and shock. That is, if the gas generating agent 43 is cracked, the surface area of the gas generating agent 43 increases, and abnormal combustion occurs.However, this combustion chamber filter 49 is used until the gas generating device for deploying an air bag is incorporated into a passenger car or the like. In this case, the gas generating agent 43 is prevented from being cracked due to a fall accident at or in a long-term vibration after being mounted on a passenger car.

Capture function of combustion products.

The function of retaining the gas generating agent 43 and securing the discharge path of the combustion gas. If there is no discharge path, the inside of the housing will be at a high pressure and may be broken.

The inside of the air charge chamber 51 is vertically divided by a partition plate 89, and an upper filter (second filter) 53 is provided above the partition plate 89, and a gas filtration filter (third filter) 55 is provided below the partition plate 89. Are located.

The partition plate 89 is made of, for example, a member such as stainless steel or aluminum, and is pressed into the inner peripheral surface of the covering member 77.
The partition plate 89 passes through the combustion chamber filter 49 and passes through the charging chamber 51.
After the combustion gas flowing into the inside flows into the upper filter 53, the flow of the combustion gas is changed, and the gas filtration filter 55
Acts to lead to.

The upper filter 53 is disposed opposite to the orifice 82 formed in the housing body 59, and is formed by, for example, press-molding a stainless steel demister wire mesh using a ring-shaped mold. The upper filter 53 has a function of causing the high-velocity combustion gas ejected from the orifice 82 to collide with the slag screen, thereby making the high-velocity combustion gas a turbulent flow and causing the combustion gas residue to adhere to the wire mesh.

The gas filtration filter 55 has a function of cooling combustion gas to such an extent that the airbag does not burn, removing combustion residues contained in the combustion gas, and supplying only harmless nitrogen gas to the airbag. It is formed by layering and winding a fine metal net, a sintered metal fiber cloth, an inorganic fiber sheet, a sintered metal fiber cloth, a woven woven metal net and a fine metal net in order from the inside.

Here, the fine wire mesh is, for example, configured by winding a stainless wire mesh of No. 10 to 45 in a cylindrical shape a plurality of times, and is necessary for cooling the combustion gas and appropriately expanding the airbag. It acts to adjust the amount of gas.

The fold woven wire mesh is made of, for example, a stainless steel wire mesh, and is wound around the outer periphery of the metal sintered cloth and acts to disperse the gas into a turbulent flow.

The inorganic fibrous sheet is wound around the inner periphery of the woven woven wire mesh via a sintered metal fiber cloth. In this embodiment, the fine particles of sodium oxide and sodium metal contained in the gas and cause a pungent odor are formed. It acts to filter the powder.

A sintered metal fiber cloth is wound adjacent to the inside and outside of the inorganic fiber sheet, and the sintered metal fiber cloth and the woven woven metal mesh prevent the inorganic fiber sheet from being broken by a gas flow. It acts to prevent.

The metal fiber sintered cloth is formed by compressing and sintering to a thickness of 0.2 to 1.0 mm using, for example, a stainless wire having a wire diameter of 4 to 8 μm at 500 g / m ^2. And the porosity is 65-90%.

Further, packings 91 are arranged above and below the gas filtration filter 55 in order to prevent gas leakage from the gas filtration filter 55.

The packing 91 is made of a heat-resistant and flame-retardant material such as silicone rubber to prevent burning, and has a thickness of 0.6 to 2.0 mm.

The igniter 45 is supported by a plug 93 screwed into a through hole formed in the center of the lid member 65.
Is filled with a seal member 95.

In the airbag deployment gas generator configured as described above, when electricity is supplied to the igniter 45, the igniter 47 burns, and by this combustion, the gas generating agent 43 burns. The gas of 43 passes through a combustion chamber filter 49 arranged along the inner periphery of the combustion chamber 41, and flows into the charging chamber 51.
After flowing into the upper filter 53, colliding with the partition plate 89 and inverting, the gas is filtered by the gas filtration filter 55, and the gas outlet 57
And flows into the airbag, and the airbag is sufficiently inflated in a short time of, for example, about 0.04 seconds.

Thus, in the combustion chamber of the gas generator for air bag deployment configured as described above, each gas generating agent 43 is formed in an annular plate shape having a through hole 44 formed at the center, and these gas generating agents 43 are formed. A through hole formed in the center by laminating the generator 43
Since the igniter 45 and the igniter 47 are arranged at 44, the porosity of the igniter is reduced as compared with the conventional case where a large number of granules or pellets of the gas generating agent 43 are filled in the combustion chamber 41. As a result, the volume of the combustion chamber 41 is reduced, and the size of the airbag deployment gas generator can be easily reduced.

Further, in the combustion chamber of the airbag deployment gas generator configured as described above, a separator is provided between the gas generating agents 43.
Since the 83 is provided, it is possible to sufficiently secure the ignitability of the gas generating agent 43 and the exhaust passage of the combustion gas.

Further, in this embodiment, the housing is constituted by the housing body 59, the lid member 65 and the cover member 65, and these are fixed to each other by welding, so that the airbag is combined with the structure of the combustion chamber 41. The deployment gas generator can be made much smaller than before.

In the above-described embodiment, the example in which the arc-shaped chamfered portion 46 is formed on the inner peripheral portion and the outer peripheral portion of the gas generating agent 43 has been described, but the present invention is not limited to such an embodiment. For example, it is a matter of course that the inner peripheral portion and the outer peripheral portion may be thin and the space between them may be thick.

Further, in the above-described embodiment, an example in which the gas generating agent 43 is formed in an annular shape has been described. However, the present invention is not limited to such an embodiment. Of course, it may be divided into two or four.

〔The invention's effect〕

As described above, according to the present invention, each gas generating agent filled in the combustion chamber is formed in an annular plate shape having a through hole in the center, and a chamfer is formed in the outer periphery and the through hole. Each of these gas generating agents is laminated on the entire surface except for the chamfered portion via an annular wire mesh separator, and is filled with an igniting agent in the space formed by each central through hole, and is surrounded by a sealed container. So, like before,
As compared with the case where a large number of granules or pellets of a gas generating agent are filled in the combustion chamber, the porosity can be significantly reduced, and as a result, the volume of the combustion chamber decreases,
It is possible to easily reduce the size of the airbag deployment gas generator.

Further, in the present invention, since the separator is arranged between the gas generating agents, it is possible to sufficiently secure the ignitability of the gas generating agent and the exhaust passage of the combustion gas, and further, the combustion gas is cooled by the separator. This has the advantage that combustion residues can be removed.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing the gas generating agent of FIG. FIG. 2 is a top view of the gas generating agent of FIG. FIG. 3 is a longitudinal sectional view showing an airbag developing gas generator provided with an embodiment of the combustion chamber of the airbag developing gas generator of the present invention. FIG. 4 is a longitudinal sectional view showing the housing body of FIG. FIG. 5 is a top view of the housing main body of FIG. FIG. 6 is a longitudinal sectional view showing the covering member of FIG. FIG. 7 is a graph showing the performance of the ignition charge. FIG. 8 is a longitudinal sectional view showing a conventional gas generator for deploying an air bag. [Description of Signs of Main Parts] 41: Combustion chamber 43: Gas generating agent 44: Through hole 45: Igniter 47: Igniter 49: Combustion chamber filter 51: Charging chamber 57: Gas outlet 59 Housing body 61 Bottom cylindrical part 69 Bottom part 67 Flange part 71 Outer cylinder part 77 Cover member 83 Separator.

 ──────────────────────────────────────────────────続 き Continued on the front page (56) References JP-A-51-125678 (JP, A) JP-A-2-24242 (JP, A) JP-A 1-145867 (JP, U)

Claims (1)

(57) [Claims] In the combustion chamber of a gas generator for deploying an airbag, wherein an igniter and an igniting agent are arranged adjacently at the center and a plurality of gas generating agents are arranged outside the igniter and the igniting agent, Is formed in an annular plate shape having a through hole at the center, and has a chamfered portion formed on the outer periphery and the through hole. A combustion chamber of a gas generator for deploying an airbag, wherein the combustion chambers are stacked one on another, filled with an igniter in a space defined by each central through-hole, and surrounded by a sealed container.