JP2002200966A - Gas generator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a gas generator capable of eliminating a working time delay by shortening the ignition time of an ignitor for the gas generator and capable of showing excellent performance by using a seat belt pre-tensioner. SOLUTION: This gas generator 34 is formed of a first cup 10 to be filled with a gas generating agent 14 for generating gas and the ignitor 12 arranged inside of the first cup 10 and having a second cup E for housing an ignition chemical. A separator 32 for covering the second cup E is arranged, and the separator 32 is provided with a flame hole 35.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a compact gas generator mainly used for operating a seat belt pretensioner of an automobile.

[0002]

2. Description of the Related Art A seatbelt pretensioner is known as one of safety devices for protecting an occupant from an impact generated at the time of an automobile collision. This pretensioner operates a cylinder with a large amount of high temperature and high pressure gas generated by a gas generator. Since this gas generator operates a cylinder instead of an airbag, the amount of generated gas is relatively small, and the gas generator has a structure in which high-temperature and high-pressure gas is directly injected into the cylinder without intervening a filter or coolant. ing. Usually, such a gas generator includes an igniter for storing an igniting agent that ignites when energized, a first cup for storing a gas generating agent, a holder for fixing the igniter and the first cup, and the like. I have.

FIG. 2 shows an example of a conventional gas generator for a seat belt pretensioner. The gas generator 108 of FIG.
Is a gas generating agent 106 that generates a large amount of gas upon ignition.
And an igniter 10 for storing an igniting agent ignited by energization.
4, a first cup 102 for storing the gas generating agent, an ignition device 104 and the first cup 102 fixed to the respective centers, and the gas generating agent 106 and the ignition device 104
2, an O-ring 105 disposed in a gap between the igniter 104 and the holder 101 to prevent moisture from entering through a gap between the igniter 104 and the holder 101, and an igniter 104. Two standing pins A
Shorting clip 1 to keep the short
07. In addition, a sealing agent (not shown) is applied to a gap between the first cup 102 and the holder 101 in order to prevent moisture from entering.

As shown in FIG. 3, the igniter 104 generally includes a second cup E for accommodating the igniting agent D, and an embolus B which is inserted and fitted into the second cup E to seal the igniting agent D. And a pin A made of two metal bars penetrating through the embolus B. Each pin A projects into the second cup E,
The tip is electrically connected by the electric bridge line F.
The electric bridge F is covered with an ignition ball C in contact with the ignition charge D.

In a conventional gas generator, an ignition device 104 is used.
Are held in the first cup 102 in a bare state. This igniter 104 has a problem of cost and assembly.
The second cup E may be made of a material such as a resin having a low material strength.

[0006] Generally, explosives such as ignition powder have a property that the burning speed is faster when burning under high pressure conditions. Therefore, if the second cup of the igniter is made of a material such as a resin having low material strength, even if the igniter in the igniter ignites, the second cup is formed before the pressure at the time of burning the igniter increases.
Since the cup breaks, the burning rate is reduced. Therefore, the time required for ignition of the igniter is usually about 2 ms,
In some cases, it may take longer.

[0007] The operation time of the gas generator generally needs to be within 2 ms, and if it is delayed more than that, sufficient performance may not be exhibited.

[0008]

SUMMARY OF THE INVENTION An object of the present invention is to shorten the ignition time of an ignition device of a gas generator, thereby eliminating a delay in operation time and exhibiting sufficient performance when used in a seat belt pretensioner or the like. It is to provide a gas generator which can be used.

[0009]

According to a first aspect of the present invention, there is provided a gas generator comprising: a first cup filled with a gas generating agent for generating gas by combustion;
A igniter disposed inside the first cup and having a second cup for storing an igniting agent, wherein a separator covering the second cup is disposed and the separator is provided. In which a flame hole is formed.

[0010] According to such a configuration, when the ignition agent in the second cup of the igniter is ignited, the separator operates.
This prevents the second cup of the igniter from breaking before the pressure at the time of burning the ignition charge increases. Thus, the igniter burns under high pressure. As a result, the combustion speed becomes higher than before, and the ignition delay of the gas generator is reduced. Here, in order to prevent the second cup of the igniter from breaking before the pressure at the time of burning the ignition charge increases, a material having high strength is preferable as the material used for the separator.
Therefore, as a separator that can be used, for example,
Metals such as iron, aluminum and stainless steel, or P
Examples include those made of BT, fluororesin, and the like. Further, if the second cup of the igniter can be prevented from breaking before the pressure at the time of burning the ignition charge increases, a mesh can be used for the separator. The separator need not cover the entire second cup, but preferably covers substantially the entire area. In addition, the gap between the separator and the second cup is preferably 1 mm or less, and more preferably 0.2 mm or less.

Further, since the separator is provided with flame holes, high-temperature and high-pressure gas or particles generated by the ignition of the igniter can be intensively ejected only in the direction in which the gas generating agent is present. Therefore, the flame holes provided in the separator are preferably arranged in the direction in which the gas generating agent is arranged.
Further, by providing the flame holes, when the separator is broken by the igniter, the fragments can be prevented from scattering in all directions.

According to a second aspect of the present invention, in the gas generator according to the first aspect, the separator holds the first cup and holds the first cup by caulking with respect to a holder holding the ignition device. Is what is being done.

According to such a configuration, even when the gas generator operates, the separator is prevented from being scattered outside the gas generator. In addition, when the igniting agent in the igniter ignites, the displacement of the separator is prevented.

Further, in the gas generator according to the third aspect, the separator according to the first or second aspect, wherein the separator comprises the second one.
The holder is held by caulking in the holder together with the plug of the cup.

According to such a configuration, it is possible to reduce the design change and the change in the assembling process due to the arrangement of the separator, compared to the conventional gas generator without the separator. .

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a gas generator according to the present invention will be described below with reference to the drawings.

In FIG. 1, the gas generator 34 includes the first cup 10, the gas generating agent 14, the igniter 12, the holder 31, and the separator 32.

The gas generating agent 14 is filled in a state of directly contacting the inner periphery of the first cup 10 without passing through a filter and / or a coolant. Here, the gas generating agent that can be used is preferably a nitrogen-containing organic compound as a fuel component, and an inorganic compound and a gas generating agent containing at least one or more additives as an oxidizing agent component.
Examples of the fuel component include at least one selected from the group consisting of aminotetrazole, guanidine nitrate, and nitroguanidine. The oxidizing agent component includes at least one selected from the group consisting of strontium nitrate, ammonium nitrate, potassium nitrate, ammonium perchlorate, and potassium perchlorate. Additives include molybdenum trioxide, a self-igniting catalyst. Other additives that can be added to the gas generating agent include a binder, and the binder includes at least one selected from the group consisting of guar gum, methyl cellulose, carboxymethyl cellulose, water-soluble cellulose ether, and polyethylene glycol. No. Suitable gas generating agents include 5-
Aminotetrazole and guanidine nitrate, strontium nitrate and ammonium perchlorate as oxidizer components,
It is a gas generating agent containing molybdenum trioxide as a self-igniting catalyst and guar gum as a binder. More preferably, 5-aminotetrazole is used as a fuel component in 10 to 3 times.
0% by mass, 15 to 35% by mass of guanidine nitrate, 10 to 30% by mass of strontium nitrate as an oxidizing agent, 15 to 35% by mass of ammonium perchlorate, 1 to 10% of molybdenum trioxide as a self-igniting catalyst %, And a gas generating agent containing 1 to 10% by mass of guar gum as a binder.

The first cup 10 has a large-diameter cylindrical portion 10a,
It has a cylindrical portion 10b having a small diameter, and has a substantially bottomed cylindrical shape whose diameter is increased in one step from the bottom side. This first cup 1
A plurality of linear notches 10c are provided at the bottom of 0. When the gas generating agent 14 stored in the first cup 10 is burned, the notch 10c is broken and the gas is directly discharged to a seat belt pretensioner (not shown).
A flange portion 10d extending radially outward is formed at the open end of the first cup 10, and is attached to the holder 31 by caulking. Examples of the material of the first cup 10 include metal materials such as stainless steel and aluminum.

As shown in FIG. 3, the igniter 12 is erected for the purpose of supplying an igniting agent D, a second cup E filled with the igniting agent D, and electricity for igniting the igniting agent D. And two embodied pins A and embolus B.

A shorting clip 11 for short-circuiting two pins A as shown in FIG. 1 is attached to the igniter 12. The shorting clip 11 is for preventing malfunction due to static electricity or the like.

In FIG. 1, the holder 31 is preferably made of a metal material such as stainless steel or aluminum. The holder 31 has a first hole 31 c for inserting and fitting the plug B portion of the ignition device 12,
And a projection 31 a for caulking the first cup 10. Holder 31
The position of the first cup 10 is fixed so that the igniter 12 is positioned at the center of the first cup 10 and the igniter 12 is fixed.
Embolus B is held. At this time, the plug B of the ignition device 12
And a sealing member such as an O-ring,
It is preferable to achieve moisture proof between the holder and the holder 31. An O-ring 33 serving as a sealing member is provided in a gap between the first cup 10 and the holder 31. A sealant is applied to an inner contact surface 31d between the holder 31 and the inner peripheral surface of the first cup 10. Due to the sealant applied to the O-ring 33 and the inscribed surface 31 d, moisture from the outside causes the inscribed surface 31 d between the first cup 10 and the holder 31.
Through the first cup 10 is prevented.

The separator 32 is formed in a cup shape so as to cover the second cup E of the igniter 12 and the tip of the plug B of the igniter 12. A flange portion 32a is formed at the opening end so as to extend diagonally outward in the radial direction along the distal end portion of the embolus B so as to be attached by caulking to the holder 31. The flange portion 32a is attached to the holder 31 together with the plug B of the igniter 12 by the swaging protrusion 31b of the holder 31 which is swaged on the flange portion 32a of the separator 32. A sealant (not shown) is applied between contact surfaces between the holder 31 and the separator 32, that is, a gap. Further, since the surface of the second cup E of the igniter 12 is covered by the separator 32, the strength increases, and when the igniting agent inside the igniter 12 is ignited and burns, the pressure inside the igniter 12 increases. The ignition charge burns under high pressure without the second cup E breaking before. As a result, the combustion speed becomes higher than before, and the ignition delay of the gas generator 34 is reduced.

The separator 32 is made of iron, aluminum,
It is formed of a metal material such as stainless steel or a resin such as PBT or fluorine resin. Further, a flame hole 35 penetrating through the separator 32 is formed on a surface in contact with the gas generating agent 14. This flame hole 35 concentrates high-temperature gas and particles of the igniter 12 toward the gas generating agent 14,
From the viewpoint of preventing the breakage of the second cup, the separator 32 is preferably provided at the bottom of the bottomed cylindrical portion that covers the second cup E. The flame hole 35 is preferably provided at the bottom of the bottomed cylindrical portion of the separator 32 as described above, but may be provided at the cylindrical portion of the cylindrical portion. The separator 32 does not need to be formed of a single member, and may be formed by combining several members, but is preferably formed of a single member from the viewpoint of reducing the number of parts. Further, it may be in a mesh shape.

It is preferable that the inner surface of the separator 32 conforms to the outer surface of the second cup E of the igniter 12 so that the second cup E of the igniter 12 and the separator 32 are substantially in close contact with each other. . The gap between the second cup E and the separator 32 is preferably 1 mm or less,
More preferably, it is 0.2 mm or less.

With such a structure, moisture that enters the gas generating agent 14 is prevented. Further, the separator 32 is disposed so as to cover the second cup E of the igniter 12, and
Since the flame holes 35 are formed in the direction of the gas generating agent 14, the energy of the igniter 12 is concentrated in the direction of the gas generating agent 14. Further, since the second cup E of the igniter 12 is covered with the separator 32, the strength increases. Therefore,
When the igniting agent D inside the igniter 12 ignites and burns, the second cup E does not break before the pressure inside the igniter 12 increases, and the igniting agent burns under high pressure. As a result, the combustion speed becomes higher than before, and the ignition delay of the gas generator 34 is reduced.

The gas generator 34 configured as above is
It can be manufactured by the following procedure. First, the igniter 12 is attached to the first hole 31c of the holder 31, and then
The igniter 12 and the separator 32 are attached by covering the surface of the igniter 12 with the separator 32 having the flame hole 35 formed thereon and caulking the caulking projection 31b.
To the holder 31 integrally. Preferably, a sealant is applied between the contact surfaces of the holder 31 and the separator 32. Further, a sheet packing may be fitted instead of the sheet material.

Next, the first cup 10 filled with the gas generating agent 14 is fitted to the holder 31 on which the igniter 12 and the separator 32 are mounted. At this time, the holder 31
An O-ring 33 serving as a seal member is provided in a portion 36 where the first cup 10 comes into contact with the O-ring 33. And the first cup 1
The crimping projection 31a of the holder 31 crimped so as to be bent onto the flange portion 10d of the 0
The first cup 10 is attached to a holder 31. The O-ring 33 seals the inner contact surface 31d between the first cup 10 and the holder 31 to prevent water from entering from outside.

Next, the operation of the gas generator 34 will be described. When a collision sensor (not shown) detects a collision of the vehicle, the pin A provided on the ignition device 12 shown in FIG. 3 is energized. Then, the electric bridge line F in the ignition device 12 generates heat, and the ignition ball C is ignited. Subsequently, the ignition of the ignition ball C causes the ignition charge D to ignite and burn. Although the inside of the igniter 12 becomes high temperature and high pressure with the combustion of the ignition charge D, the second cup E of the igniter 12 is covered and reinforced by the separator 32 as shown in FIG. For,
This prevents the igniter 12 from expanding and breaking before the ignition agent D is sufficiently burned.

The explosives and the like used for the igniting charge D increase in combustion speed as the pressure increases, and as a result, the igniter 12 is broken faster than the case where the igniter D is not covered with the separator 32. . Gases and particles that have been further burned and have become high temperature and high pressure are released toward the separator 32. At this time, the flame holes 3 of the separator 32
5, high-temperature and high-pressure gas and particles are ejected to the gas generating agent 14 in the first cup 10 at a stretch. And
The gas generant 14 is ignited. The separator 32
Is fixed to the holder 31 and is not blown off toward the gas generating agent 14 side.

Subsequently, the combustion of the gas generating agent 14 causes the first
A large amount of gas generated in the cup 10
, The notch 10c provided at the bottom of the first cup 10 is broken, and is introduced into a seatbelt pretensioner (not shown), whereby the seatbelt pretensioner operates.

Although the gas generator according to the present invention is configured as described above, the gas generator according to the present invention is not limited to the above-described embodiment. Can also be applied.

For example, in the above embodiment, the igniter 1
Although the description has been given of the case where the embolus B and the holder 31 are separate bodies, the igniter 12 and the embolus B may be integrally formed of resin or the like. In this case, the separator is the first
The holder is caulked together with the cup 10 in the holder 31. Thus, the separator covers the second cup E, reinforces the second cup E, and also acts as an embolus of the first cup 10.

[0034]

According to the gas generator of the present invention, since the flame holes are formed in the separator, flames and the like from the igniter are intensively jetted toward the gas generating agent, so that the operation time is delayed. No, it can be used as a gas generator that can exhibit sufficient performance when used in a seat belt pretensioner or the like.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of an example of an embodiment of a gas generator according to the present invention.

FIG. 2 is a schematic sectional view of an example of a conventional general gas generator.

FIG. 3 is a schematic sectional view of an ignition device of a general gas generator.

[Explanation of symbols]

 B Embolus E 2nd cup 10 1st cup 11 Shorting clip 12 Ignition device 14 Gas generating agent 31 Holder 32 Separator 33 Seal member 34 Gas generator 35 Flame hole

Continued on the front page (72) Inventor Kenjiro Ikeda 3903-39, Tomimachi, Himeji-shi, Hyogo F-term (reference) in Nippon Kayaku Co., Ltd. Himeji Plant 3D018 MA00 4G068 DA08 DA10 DB14 DB26

Claims (3)

[Claims] 1. A first cup (10) filled with a gas generating agent (14) that generates a gas by combustion, and disposed inside the first cup (10) and containing an igniting agent (D). A gas generator (34) comprising: an igniter (12) having a second cup (E), wherein a separator (32) covering the second cup (E) is provided and the separator (32) is provided. 32) A gas generator in which a flame hole (35) is formed. 2. The method according to claim 1, wherein the separator (32) is provided with the first
While holding the cup (10), the igniter (1
The gas generator according to claim 1, wherein the gas generator is held by caulking with respect to a holder (31) holding 2). 3. The gas generator according to claim 2, wherein the separator (32) is held together with the igniter (12) by caulking in the holder (31).