JP2008030971A - Ignition powder, initiator, gas generator, air bag unit and seat belt unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ignition powder having reduced friction sensitivity, an initiator having the ignition powder, a gas generator equipped with the initiator and an air bag unit and a seat belt unit, each having the gas generator. <P>SOLUTION: The ignition powder contains zirconium, potassium perchlorate and potassium nitrate, wherein it is preferable that the compounding ratio thereof is 40-60 wt.% zirconium, 10-55 wt.% potassium perchlorate and 1-35 wt.% potassium nitrate. A resin or rubber-based binder is added if need. The initiator is loaded with the ignition powder. The gas generator is provided with the initiator. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an ignition agent, an initiator using the ignition agent, and a gas generator including the initiator. This gas generator is incorporated in an airbag device or a seat belt device of an automobile, for example.

  An airbag device provided in a high-speed moving body such as an automobile is configured to rapidly inflate a bag-like airbag with a gas generator called an inflator. The gas generator includes a gas generating agent and an initiator for starting a gas generating reaction of the gas generating agent. The initiator includes a reactive agent and a filament (bridge wire) as a resistance heating element for initiating the reaction of the reactive agent (for example, US Pat. No. 5,404,263).

  An example of the conventional initiator will be described with reference to FIG.

  The initiator 10 has a substantially cup-shaped casing 12 whose rear part (lower part in FIG. 1) is open. An ignition powder 14 is accommodated in the casing 12. The rear part of the casing 12 is closed by an insulating material 16 made of sintered glass or the like. In the casing 12, the front ends of a pair of electrodes 18 and 20 that penetrate the insulating material 16 face.

  A filament 22 is installed between the tips of the electrodes 18 and 20. Both end sides of the filament 22 are welded to the tip surfaces of the electrodes 18 and 20. The filament 22 is in contact with the ignition powder 14 in the casing 12.

  The electrodes 18 and 20 and the casing 12 are arranged apart from each other so as not to make electrical contact.

  In the initiator 10 thus configured, one electrode 18 is connected to the positive electrode of the vehicle battery 26 via the control circuit 24 having a voltage booster circuit and the like, and the other electrode 20 is connected to the vehicle body of the vehicle ( Earth connection). The negative electrode of the battery 26 is connected to the vehicle body.

  In an emergency such as a vehicle collision, the switch element in the control circuit 24 is turned on, and a voltage is applied from the battery 26 to the filament 22 via the electrodes 18 and 20. As a result, the filament 22 generates heat, the ignition powder 14 is ignited, and the reaction starts. The reaction of the ignition powder 14 generates high-pressure gas and heat, and the gas generating agent in the gas generator causes a gas generating reaction.

  An example of a gas generator provided with the initiator 10 will be described with reference to FIG. The gas generator 30 includes a container including an outer shell body including an upper housing 32 and a lower housing 34 and a cylindrical partition member 36 installed in the outer shell body. One end of the partition member 36 passes through the opening on the bottom surface of the lower housing 34 and protrudes downward. The inner peripheral surface of the opening and the outer peripheral surface of the partition member 36 are welded by laser beam welding or the like. A transfer charge (booster propellant) 40 is accommodated inside the partition member 36, and a gas generating agent (main propellant) 42 is accommodated on the outer peripheral side of the partition member 36.

  The initiator 10 is installed at the one end of the partition member 36. When the transfer charge 40 is ignited by the initiator 10, gas is ejected from the opening 44 of the partition member 36, the gas generating agent 42 is ignited, and a large amount of gas is rapidly generated. 46, the air bag is inflated through the opening 48 to the outside of the gas generator 30. FIG. 2 is an example of a gas generator, and many types of gas generators having shapes other than those shown are used.

  As this igniting agent, there are those mainly composed of zirconium and potassium perchlorate.

  For example, claim 5 of JP-A-9-504599 includes 30 to 60% by weight of zirconium, 30 to 60% by weight of potassium perchlorate, 1 to 10% by weight of flake aluminum, 2 to 8% by weight of Kraton G, and Kraton. An electrical initiator comprising a primer containing 0.1 to 5% by weight of FG is described.

JP-A-6-207799 describes an igniting agent containing 20 to 50% by weight of zirconium, 40 to 60% by weight of potassium perchlorate and 5 to 20% by weight of pigmental aluminum. In addition, paragraph 0012 of the same publication discloses that a fluorine-based resin and a silicon adhesive are added as a resin-based binder.
US Pat. No. 5,404,263 Special table hei 9-504599 JP-A-6-207799

  In general, an ignition powder mainly composed of zirconium and potassium perchlorate has high friction sensitivity.

  The present invention relates to a zirconium-potassium perchlorate-based igniting agent with reduced friction sensitivity, an initiator having the igniting agent, a gas generator including the initiator, and an airbag device including the gas generator. And a seat belt device.

  The igniting agent according to claim 1 is characterized in that in the igniting agent containing the fuel component and the oxidizing agent, zirconium is contained as the fuel component and potassium perchlorate and potassium nitrate are contained as the oxidizing agent.

  The igniting agent according to claim 2 is characterized in that, in claim 1, zirconium includes 40 to 60% by weight of potassium perchlorate, 10 to 55% by weight, and potassium nitrate to 1 to 35% by weight.

  The igniting agent according to claim 3 is characterized in that, in claim 2, it contains 45 to 55 wt% zirconium perchlorate 20 to 45 wt% potassium nitrate 2 to 30 wt%.

  The igniting agent according to claim 4 is characterized in that, in any one of claims 1 to 3, it further contains a resin or a rubber-based binder.

  The igniting agent according to claim 5 is characterized in that, in claim 4, the content of the binder is 0.5 to 5% by weight.

  The igniting agent of claim 6 is characterized in that, in any one of claims 1 to 5, boron or tungsten is further contained as a fuel component.

  An initiator according to a seventh aspect comprises the ignition agent according to any one of the first to sixth aspects.

  A gas generator according to an eighth aspect comprises the initiator according to the seventh aspect.

  The airbag apparatus according to claim 9 is an airbag apparatus comprising an airbag and a gas generator for inflating the airbag, wherein the gas generator is the gas generator according to claim 8. It is characterized by this.

  The seat belt device according to claim 10 is provided with a seat belt and a pretensioner that applies pretension to the seat belt by gas pressure from the gas generator in an emergency, and the gas generator claims The gas generator according to Item 8, wherein the gas generator is characterized in that

  As a result of various studies, the present inventor has found that friction sensitivity is lowered by adding potassium nitrate in an ignition agent containing zirconium as a fuel component and potassium perchlorate as an oxidant. The present invention is based on such knowledge. If the friction sensitivity of the ignition powder is reduced, the management cost can be reduced and the initiator can be manufactured at a low cost.

  By adding a resin or rubber binder to the ignition agent, the ignition agent becomes easy to handle.

  The igniting agent of the present invention contains zirconium as a fuel component, and contains potassium perchlorate and potassium nitrate as oxidant components.

  The preferred composition of the fuel component of this igniting agent is as follows.

Zirconium: 40-60% by weight, especially 45-55% by weight
Potassium perchlorate: 10-55% by weight, especially 20-45% by weight
Potassium nitrate: 1 to 35% by weight, especially 2 to 30% by weight

  Zirconium is preferably a powder having a particle size of 10 μm or less, and its average particle size is preferably 5 μm or less, particularly preferably about 0.5 to 3.0 μm. The average particle size of potassium perchlorate and potassium nitrate is preferably about 3 to 10 μm. The particle size of the powder can be measured using, for example, a sieve.

The igniting agent of the present invention may consist of only the above components, and may further contain boron or tungsten as a fuel component. The boron content in the ignition agent is preferably 10% by weight or less, for example 2 to 8% by weight, and the tungsten content is preferably 40% by weight or less, for example 5 to 38% by weight.
The average particle size of boron is preferably 5 μm or less, and the average particle size of tungsten is preferably 5 μm or less.
In the present invention, a resin such as fluororubber, fluororesin, or silicone resin or a rubber-based binder may be blended in the ignition agent to facilitate handling. The blending amount of the binder is preferably 5% by weight or less, particularly about 0.5 to 5% by weight in the total 100% by weight with the above ignition components.

  Such an igniting agent is filled in the initiator as shown in FIG. 1, for example. This initiator is incorporated in the gas generator as shown in FIG. However, the configurations of the initiator and the gas generator are not particularly limited, and can be applied to various types other than those illustrated.

  Next, an example of a gas generator provided with the initiator 10 of FIG. 1, and an airbag device and a seat belt device provided with the gas generator will be described with reference to FIGS.

  FIG. 3 is a longitudinal sectional view of an airbag apparatus equipped with the gas generator of FIG.

  The air bag device 80 is folded with the gas generator 30 of FIG. 2, an air bag 81 that is inflated by the gas from the gas generator 30, and a retainer 82 that holds the gas generator 30 and the air bag 81. A module cover 83 attached to the retainer 82 is provided so as to cover the airbag 81.

  The airbag 81 has a front surface facing a vehicle occupant and the like when inflated and a rear surface opposite to the front surface, and an opening (mouth portion) 81a into which the gas generator 30 is inserted. ing.

  The retainer 82 includes a main plate portion 82a and leg piece portions 82b bent downward from the peripheral edge portion of the main plate portion 82a. A gas generator insertion port 82c is provided at the center of the main plate portion 82a. As shown in FIG. 3, the leading side of the gas generator 30 is inserted into the gas generator insertion port 82c from the back side of the main plate portion 82a. The mouth portion 81a of the airbag 81 is overlapped with the peripheral edge portion of the gas generator insertion port 82c and fixed by the attachment ring 84. The leading side of the gas generator 30 is disposed in the airbag 81 through the mouth portion 81a.

  Bolts (stud bolts) 84a project from the mounting ring 84, and the bolts 84a are provided around the insertion holes (reference numerals omitted) around the mouth portion 81a and around the gas generator insertion port 82c, and the flange 69. The airbag 81 and the gas generator 30 are fixed to the retainer 82 by being inserted into the insertion hole 70 and extending to the back side of the flange 69 and the nut 84b is fastened to the bolt 84a.

  The airbag device 80 is configured by folding the airbag 81 and mounting the module cover 83 so as to cover the folded body of the airbag 81.

  In this embodiment, a leg piece 83a is erected downward from the back surface of the module cover 83, and the leg piece 83a is fixed to the leg piece 82b of the retainer 82 by a fixing tool 83b such as a rivet. Has been. The module cover 83 is configured to be pushed and cleaved by the airbag 81 when the airbag is inflated. Reference numeral 83c indicates a tear line that induces this cleavage.

  In the gas generator 30 and the airbag device 80 having such a configuration, when the electrodes 18 and 20 of the initiator 10 are energized, the igniting agent 14 in the initiator 10 reacts, and thereby the igniting agent 40 is ignited. Next, the gas generating agent 42 is ignited by the high-temperature gas from the transfer charge 40 through the opening 44 to generate gas. This gas passes through the filter 46 and is ejected from the opening 48, that is, into the airbag 81. As a result, the airbag 81 is inflated. The airbag 81 inflates and deploys the module cover 83 so as to face the vehicle occupant and the like, thereby protecting the vehicle occupant and the like.

  FIG. 4 is an overall view of a seat belt apparatus provided with a gas generator, and FIG. 5 is an exploded perspective view of a retractor (pretensioner) of the seat belt apparatus.

  One end of the seat belt 91 of the seat belt device 90 is connected to a retractor 92 so that the seat belt 91 can be wound, and the other end is fixed to the vehicle body by an anchor 93. The middle part of the seat belt 91 is passed through a shoulder anchor 94 and a tongue 95, respectively. The anchor 93 is disposed on the side surface of the passenger compartment of the seat. A buckle device 96 for latching the tongue 95 is provided on the side of the seat opposite to the anchor 93. The shoulder anchor 94 is disposed at the upper part of the side surface of the passenger compartment.

  In this embodiment, the retractor 92 includes a pretensioner that applies pretension to the seat belt 91 in the event of a vehicle emergency, and an impact absorbing mechanism (EA mechanism) that absorbs an impact applied to the occupant from the seat belt 91. It has been. Hereinafter, the configuration of the retractor 92 will be described with reference to FIG.

  A spool 98 is accommodated in the base frame 97 of the retractor 92, and one end side of the seat belt 91 is wound around the spool 98. As the spool 98 rotates, the seat belt 91 is wound and unwound. A torsion bar 99 is disposed at the shaft center of the spool 98, and one end of the torsion bar 99 is supported by the support member 102 via the lock mechanism parts 100 and 101.

  The torsion bar 99 is a main part of the EA mechanism. When the tension of the seat belt 91 exceeds a predetermined value, the torsion bar 99 is plastic torsionally deformed, and accordingly, the spool 98 rotates in the unwinding direction of the seat belt 91 while receiving drag. .

  A gear 103 is provided at one end of the spool 98 (left end in FIG. 5). This gear 103 is engaged with a gear (not shown) in the return spring cover 104 shown at the lower left end of the lower stage of FIG. The spool 98 is biased in the direction of winding the seat belt 91 by a return spring (not shown) in the return spring cover 104.

  A pipe 107 is provided between the pretensioner cover 105 shown on the right side of the return spring cover 104 in FIG. 5 and the pretensioner plate 106 shown on the lower right end of FIG. Yes. A gas generator 108 is attached to one end of the pipe 107. A spring 109, a piston 110, and a plurality of balls 111 are arranged inside the pipe 107. A notch-shaped opening (reference numeral is omitted) is formed on the side surface near the other end of the pipe 107. A guide block 112 is fitted on the other end side of the pipe 107.

  The pretensioner cover 105 is provided with a pin 113, and a ring gear 114 having external teeth and internal teeth is held on the pin 113. The pipe 107 is disposed so as to go around the outer periphery of the ring gear 114. The pipe 107 is arranged such that the direction from the one end side to the other end side is the seat belt winding rotation direction of the spool 98. The opening is arranged so as to face the outer peripheral surface of the ring gear 104, and the leading ball 111 exposed in the opening engages with the outer teeth of the ring gear 104.

  The root portion 115 of the gear 103 is provided with a pinion 116 that can mesh with the inner teeth of the ring gear 114. When the ring gear 114 is held by the pin 113, the ring gear 114 and the pinion 116 are not engaged.

  When the gas generator 108 performs gas ejection operation, gas is supplied into the pipe 107, and the ball 111 moves in the other end side of the pipe 107, that is, the seat belt winding direction of the spool 98 by this gas pressure. At this time, when the leading ball 111 presses the ring gear 114, the pin 113 is bent and the holding of the ring gear 114 by the pin 113 is released, and the ring gear 114 meshes with the pinion 116.

  As a result, the spool 98 is urged in the seat belt winding rotation direction by the gas pressure from the gas generator 108 via the pinion 116, the ring gear 114 and the ball 111, and the seat belt 91 is wound around the spool 98. . Thereby, pretension is applied to the seat belt 91.

  In this embodiment, the gas generator 108 includes a substantially cylindrical housing, in which the gas generating agent and the initiator 10 shown in FIG. 1 are accommodated.

  In the gas generator 108 and the seat belt device 90 having such a configuration, when the initiator 10 is energized, the ignition agent 14 reacts, whereby the gas generating agent is ignited and gas is generated. Then, gas is ejected from the gas generator 108 into the pipe 107 by this gas pressure. As a result, the pretensioner mechanism of the retractor 92 operates as described above to apply pretension to the seat belt 91.

  Each of the above-described embodiments is an example of the present invention, and the present invention may take forms other than those illustrated. For example, the initiator of the present invention can be incorporated into various gas generators other than those described above. Further, this gas generator can be incorporated into various airbag devices and seat belt devices other than those described above.

  Hereinafter, examples and comparative examples will be described.

Examples 1-5, Comparative Example 1
Zirconium, potassium perchlorate and potassium nitrate and a fluororubber binder were mixed in the ratio shown in Table 1 to prepare an ignition agent.

  Zirconium having an average particle diameter of about 1 μm was used. Potassium perchlorate and potassium nitrate having an average particle size of about 7 μm pulverized by a ball mill were used. As the fluororubber, DuPont "Viton (registered trademark)" was used and dissolved in 50 ml of acetone per 1 g. These were mixed, dried, loosened, and used as an ignition powder. The friction sensitivity of each ignition powder was measured by JISK4810 (explosives performance test method). The results are shown in Table 1.

  Moreover, 50 mg of each ignition powder was measured to the metal cup. An initiator was assembled by press-fitting a header welded with a φ20 μm nichrome wire with a constant pressing force (1000 N). A constant current of 1.2 A × 2 ms was applied to the assembly as described above, the light at the time of ignition and ignition was detected by an optical sensor, and the ignition time was measured.

  The results are also shown in Table 1.

  As shown in Table 1, each of Examples 1 to 5 has lower friction sensitivity than Comparative Example 1. The average ignition time is slightly longer than that of Comparative Example 1, but is sufficient for practical use.

  In addition, Examples 1-5 are the composition systems which substituted a part of potassium perchlorate in the comparative example 1 with potassium nitrate. Therefore, assuming that the oxygen of potassium perchlorate was substituted with the oxygen of potassium nitrate based on the blending ratio of potassium perchlorate and potassium nitrate, the substitution ratio was calculated and shown in Table 1 as the oxygen substitution rate.

  Examples 1-5 are the compound which substituted 5-50% of oxygen of potassium perchlorate with potassium nitrate, and it is recognized that the friction sensitivity is falling in this range.

It is sectional drawing which shows an example of an initiator. It is sectional drawing which shows an example of a gas generator. It is a longitudinal cross-sectional view of the airbag apparatus provided with the gas generator of FIG. 1 is an overall view of a seat belt device provided with a gas generator. It is a disassembled perspective view of the retractor of the seatbelt apparatus of FIG.

Explanation of symbols

10 Initiator 14 Ignition powder 30,108 Gas generator 40 Transfer charge (Booster propellant)
42 Gas Generating Agent 80 Airbag Device 90 Seat Belt Device

Claims (10)

  An igniting agent containing a fuel component and an oxidant, comprising zirconium as a fuel component, and containing potassium perchlorate and potassium nitrate as an oxidant. In claim 1,
Zirconium 40-60% by weight
10-55% by weight potassium perchlorate
1 to 35% by weight of potassium nitrate
An ignition powder characterized by containing. In claim 2,
Zirconium 45-55 wt%
Potassium perchlorate 20-45% by weight
2-30% by weight potassium nitrate
An ignition powder characterized by containing.   The igniting agent according to any one of claims 1 to 3, further comprising a resin or a rubber-based binder.   The igniting agent according to claim 4, wherein the content of the binder is 0.5 to 5% by weight.   The igniting agent according to any one of claims 1 to 5, further comprising boron or tungsten as a fuel component.   An initiator comprising the ignition powder according to any one of claims 1 to 6.   A gas generator comprising the initiator according to claim 7.   An airbag device comprising an airbag and a gas generator for inflating the airbag, wherein the gas generator is the gas generator according to claim 8. In a seat belt apparatus comprising a seat belt and a pretensioner that applies pretension to the seat belt by gas pressure from a gas generator in an emergency,
The seat belt device according to claim 8, wherein the gas generator is the gas generator according to claim 8.

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