JP2005156038A - Initiator, and gas producer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an initiator capable of using a reaction drug with easy production and safe handling, and a gas producer provided with the initiator. <P>SOLUTION: The reaction drug 58 is held in a cup 52 of the initiator 50. Pins 60 and 60 are inserted in a hole 54a of a header 54, and plates 62 are fixed to their tips. A conductive ignition element 64 formed by binding an ignition chemical by a conductive binder is arranged between the plates 62. When a voltage is applied between the pins 60 and 60, a high temperature reaction product is produced from the conductive ignition element 64, and the reaction drug 58 starts to react. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an initiator suitable for incorporation in a gas generator such as an airbag device or a seat belt pretensioner, and a gas generator including the initiator.

  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. Conventionally, this 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 this 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. 2) is open. A reactive agent 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 reactive agent 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 reactive agent 14 is ignited, and the reaction starts. The reaction of the reactive agent 14 generates high-pressure gas and heat, whereby the gas generating agent in the gas generator causes a gas generating reaction.

As the reactive agent, for example, a first reactive agent made of a mixture of lead stiffate and aluminum powder arranged so as to surround the filament 22, and BKNO ₃ or black explosive arranged so as to surround the first reactive agent. A second reactive agent is used. The first reactive agent rapidly undergoes an exothermic reaction, and the second reactive agent starts to react with the heat of the first reactive agent to generate high-pressure hot gas and fine particles.

  An example of a gas generator provided with this 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. An ignition agent (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 igniting agent 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. 3 is an example of a gas generator, and many types of gas generators having shapes other than those shown are used. An initiator using a bridge wire is also described in WO01 / 031281 and the like.
US Pat. No. 5,404,263 WO01 / 031281

  In the conventional initiator shown in FIG. 3, in order to conduct heat of the bridge wire to the igniting agent, the supplied power cannot necessarily be transmitted to the igniting agent 100% (loss may occur). ).

  An object of the present invention is to provide an initiator that can use a reactive agent that does not use a resistance heating element such as a filament, is easy to manufacture, and is safe to handle. Another object of the present invention is to provide a gas generator equipped with this initiator.

  The initiator of the present invention contains a casing, a reactive agent disposed in the casing, an ignition agent that is disposed in the casing and ignites when energized to start the reaction of the reactive agent. The conductive igniter is provided.

  As the conductive igniter, a material obtained by solidifying an igniting agent with a conductive binder is preferable.

  In the initiator of the present invention, when a voltage is applied to the electrode, the conductive igniter is energized, and the ignition agent in the conductive igniter starts to react. The reaction agent starts to react by the heat generated at this time, and the gas generating agent of the gas generator is ignited by the high-pressure gas and heat generated by this reaction. Since this initiator is provided with a conductive igniter instead of a filament, it is easy to manufacture, and an initiator having no quality variation can be manufactured at a high yield and at a low cost.

  In addition, the conductive igniter itself reacts to generate a reaction product such as a high-temperature and high-pressure gas, and this reaction product initiates the reaction of the reactive agent, so that the conductive igniter and the reactive agent are in close contact with each other. Even if it is not, the reaction agent surely starts the reaction.

  The gas generator with this initiator constantly checks the resistance value of its conductive igniter by the electronic control unit of the vehicle equipped with the airbag device incorporating it, and confirms that the resistance value is in the normal range. can do.

  Hereinafter, embodiments will be described with reference to the drawings. 1A is a longitudinal sectional view of an initiator according to an embodiment of the present invention, FIG. 1B is a sectional view taken along line BB of FIG. 1A, and FIG. 1C is a perspective view of a header.

  In the initiator 50 of FIG. 1, a casing is constituted by a cup 52 and a header 54 inserted into an inlet portion of the cup 52, and a reactive agent 58 is filled in the casing. In this embodiment, the cup 52 has a circular container shape made of SUS304 or the like. The header 54 is a substantially disk-shaped member made of a non-conductive material such as ceramic or synthetic resin, and the cup 52 is fixed to the outer peripheral surface thereof by caulking or the like.

  Metal pins 60 are respectively inserted into the two pin insertion holes 54a provided in the header 54, and are fixed by glass, adhesive or the like. When the header 54 is made of a synthetic resin, the pins 60 may be integrated by insert molding. The lower end of the pin 60 extends below the header 54.

  On the upper surface of the header 54, two circular recesses 54b concentric with the pin insertion holes 54c are provided. These circular recesses 54b are connected to each other through a groove 54c. A circular metal plate 62 is integrally provided at the upper end of the pin 60, and each plate 62 is disposed in a circular recess 54b. In addition, you may employ | adopt what fixed the plate of another body to the upper end of a pin.

  The conductive igniter 64 is filled in the groove 54c. In this embodiment, the conductive igniter 64 is obtained by hardening an igniting agent with a conductive binder, and is disposed so as to contact both plates 62. It is preferable that the conductive igniter 64 is filled in the groove 54c by filling the groove 54c with a paste-like material before the binder is hardened, and then heating and curing as necessary. In this way, the cross-sectional area of the conductive igniter 64 becomes constant, and the resistance value of the conductive igniter 64 is stabilized. In addition, when filling this groove part 54c with this paste, it is desirable for the plate 62 to be arrange | positioned in the recess 54b.

  The upper surface of the cup 52 is provided with a cross-shaped groove 52a for starting the cleavage of the cup 52 when the reactive agent 58 starts reaction. A seal ring 66 is interposed between the side peripheral surface of the cup 52 and the side peripheral surface of the header 54.

The reactive agent 58 may consist of only the first reactive agent (ignition agent), or may consist of a mixture of the first reactive agent and the second reactive agent (oxidant particles). There are no particular limitations on the first reaction agent, Mg, Zr, Ti, W , B, Si, C, Be, Li, Al, V, CaC 2, Ca, Ce, elemental metal or an alloy such as La, Compounds etc. are used. There are no particular limitations on the second reaction _{agent, KClO 4, KClO 3, KIO} 4, NH 4 ClO 4, NH 4 NO 3, KNO 3, Fe 2 O 3, Fe 3 O 4, Sr (NO 3) 2 CuO, NiO, etc. are used.

  As the ignition agent, the same as the reactive agent is used. (It is different from the reaction agent that it is hardened using a conductive binder.) As a conductive binder for hardening this igniting agent, fine particles such as silver, copper, nickel and graphite having high conductivity are blended. Conductive epoxy resin, conductive paint and the like can be used. The proportion of the conductive binder is preferably about 20 to 50% by weight in the conductive igniter.

  In addition, these chemical | medical agents, an electroconductive binder, and the compounding ratio are examples, and this invention is not limited to these.

  In the initiator 50 configured as described above, when a voltage is applied between the pins 60 and 60, the conductive igniter 64 is energized through the plate 62, and the conductive binder in the conductive igniter 64 is discharged. Heat is generated, and the igniting agent in the conductive igniter 64 reacts by the heat, and a reaction product such as a high-temperature gas is generated. This heat causes the reactive agent 58 to start a reaction, and a gas containing hot fine particles is generated at a high pressure. When the reactive agent 58 contains oxidant particles, the metal particles rapidly oxidize due to the oxidizing action of the oxidant particles to generate heat, and the reaction is accelerated.

  In this embodiment, the filament (wire bridge) is not used, and the labor of manufacturing is greatly reduced.

  In this embodiment, the high-temperature reaction product is stably generated by the conductive igniter 64. For this reason, the reactive agent (ignition agent) is surely ignited and the handling of the reactive agent is facilitated.

  The conductive igniter used in this embodiment is obtained by solidifying an igniting agent using a conductive binder such as a conductive epoxy, and for many years, the degree of contact with the electrode and the resistance value are electronically controlled on-vehicle. Can be checked by the device. In addition, this conductive igniter can reduce its heat capacity, thereby improving the ignition efficiency.

  The amount of current supplied to the initiator is the same as that of the prior art, for example, about 1.2 A × 2 mSec.

  The initiator of the present invention can be applied to various gas generators. The gas generator can be incorporated in various airbag devices such as a driver seat, a passenger seat, a rear seat, a side, a head protection, a pedestrian protection, and a seat belt tensioner.

(A) is a cross-sectional view of an initiator according to an embodiment of the present invention, (b) is a cross-sectional view taken along the line BB of (a), and (c) is a perspective view of the vicinity of the upper surface of the header. It is sectional drawing of the initiator which concerns on a prior art example. It is sectional drawing which shows an example of a structure of a gas generator.

Explanation of symbols

50 Initiator 52 Cup 54 Header 58 Reactive Agent 60 Pin 62 Plate 64 Conductive Igniter

Claims (3)

  A casing, a reactive agent disposed in the casing, a conductive igniter containing an ignition agent, which is disposed in the casing and ignites when energized to start a reaction of the reactive agent. Initiator comprising.   2. The initiator according to claim 1, wherein the conductive igniter is obtained by solidifying an ignition agent with a conductive binder.   A gas generator comprising a gas generating agent and an initiator for initiating a gas generating reaction of the gas generating agent, wherein the initiator is the initiator according to claim 1 or 2.

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