JP5466866B2 - Inflator for airbag - Google Patents

Description

  The present invention relates to an inflator that generates gas to be supplied to an airbag installed in an automobile as a safety device.

  The airbag device protects an occupant from an impact at the time of collision by deploying the airbag with gas generated by an inflator.

  FIG. 5 is a cross-sectional view illustrating an example of the structure of a single stage inflator 1 (for example, Patent Document 1). Reference numeral 2 denotes a housing constituted by a diffuser 2a, an adapter 2b, and a base 2c. The housing 2 includes, for example, the following components.

  3 is an initiator that is ignited by an electric signal, and 4 is a tube that partitions the initiator 3 and the gas generating agent 7, both of which are attached to the adapter 2b. Further, a cup 6 containing an ignition powder 5 is disposed inside the tube 4.

  A filter 8 is disposed on the inner peripheral side of the side wall of the housing 2, and an aluminum foil 9 is attached to the gas ejection hole 2 aa provided in the side wall of the diffuser 2 a.

The flow of gas generation in the inflator 1 having the above configuration will be described below.
The initiator 3 is ignited by the ignition signal from the vehicle (a in FIG. 5), and the ignition powder 5 in the cup 6 is ignited (from (b) to (c) in FIG. 5).

  When the ignition agent 5 is ignited, the flame is discharged to the gas generating agent 7 through the slits 6a and 4a provided in the cup 6 and the tube 4 (FIG. 5D), and the gas generating agent 7 is ignited and burned (FIG. 5). 5) A large amount of gas is generated instantaneously (f in FIG. 5).

  The generated gas is filtered through a filter 8 disposed along the inner peripheral side of the side wall of the housing 2 to remove dust and the like, and then an aluminum foil 9 attached to a gas ejection hole 2aa provided on the side wall of the diffuser 2a. The air bag is deployed.

  As shown in FIGS. 6 and 7, the gas generation amount and generated gas temperature generated during combustion of the gas generating agent in the case of the inflator having the above configuration are large in initial gas generation amount and high in gas temperature. Therefore, the tank pressure expressed as the inflator output by integrating the gas generation amount and the generated gas temperature also increases as shown in FIG.

  As a result, the damage to the airbag module at the time of ignition of the airbag and the effect on the damaging effect on the occupant increased, and there was a concern about the reduction of the initial increase in tank pressure.

JP 2008-105618 A

  Since the conventional inflator has a high combustion speed at the initial stage of operation, the initial increase rate (increase speed) of the tank pressure expressed as the inflator output becomes high (fast). The problem to be solved by the present invention is that, in the case of a conventional inflator, for the reasons described above, the damage to the airbag module at the time of ignition of the airbag and the influence on the damaging effect on the passenger are increased.

  The inflator for an air bag according to the present invention has the following in order to reduce the amount of gas at the initial generation when the gas generating agent is ignited from the igniting agent and generate gas over a long period of time. The composition is to be adopted.

That is, the inflator for an airbag of the present invention is
Inside the housing,
at least,
An initiator ,
An ignition agent that is ignited by ignition of the initiator,
A gas generating agent that is ignited and burned by the ignition of the ignition powder;
A tube for partitioning the gas generating agent and the initiator and the ignition agent ;
A filter disposed on the inner peripheral side of the side wall of the housing in order to form a housing for the gas generating agent with this tube;
An inner lid that covers this filter and the tube is disposed,
A through-hole that allows a gap to be formed between the inner cover and the housing that covers the filter and the tube, and that discharges a flame generated by ignition of the ignition agent into the gap. And a through hole is provided at a position communicating with the outer peripheral side of the tube, and the flame generated by the ignition of the ignition powder is bypassed above the upper end of the tube, and is guided from above the gas generating agent. The most important feature is that the gas generating agent is combusted from above, and the generated gas is jetted out of the housing through the filter .

  In the present invention, as a means for diverting the flame generated in the tube above the upper end of the tube and guiding it from above the gas generating agent, for example, a slit for releasing the flame is not provided on the side wall of the tube. The inner lid may be provided with a through hole for releasing the flame.

  By doing so, the gas generating agent burns from the upper side to the lower side of the gas generating agent compared to the conventional case where the gas generating agent burns in the radial direction from the vicinity of the igniting portion, so the combustion surface area per unit time is small and constant. Thus, a small amount of gas generation continues for a long time in a constant state.

  In the present invention, “upward” refers to the direction from the base 2c of the housing 2 toward the diffuser 2a, and “downward” refers to the opposite direction.

  In the present invention, compared with the conventional inflator, since a small amount of gas generation continues in a stable state for a long time, the initial rise in tank pressure can be suppressed, damage to the airbag module at the time of airbag ignition, The impact on the harmfulness is reduced. On the other hand, a sufficient amount of gas can be obtained for restraining the passenger.

  Further, since the deployment behavior of the airbag becomes gentle, the components of the airbag module can be simplified.

It is sectional drawing which shows an example of the structure of the inflator of this invention. It is a perspective view of a tube, (a) is the tube of this invention, (b) is the conventional tube. It is a perspective view of the inner lid of the present invention. It is a prediction figure of the gas generation amount generated at the time of combustion of the gas generating agent in the present invention and the conventional inflator. It is sectional drawing which shows an example of the structure of a single stage type inflator. It is a figure showing the gas generation amount generated at the time of combustion of the gas generating agent in the inflator of FIG. It is a figure showing the gas temperature generated at the time of combustion of the gas generating agent in the inflator of FIG. It is a figure showing the tank pressure expressed as an inflator output by integration of gas generation amount and generated gas temperature.

  In the present invention, for the purpose of reducing the amount of gas at the initial stage of gas generation, the flame generated by the ignition of the ignition agent inserted in the tube is bypassed above the upper end of the tube and guided from above the gas generating agent. This was realized by burning the gas generating agent.

Hereinafter, an exemplary embodiment for carrying out the present invention will be described with reference to FIG.
In order to suppress an increase in the initial rise in tank pressure, the inventors reduced the amount of gas generated at the initial generation when the gas generating agent is ignited from the igniting agent to generate gas. We thought that it should be continued in a stable state for a long time.

  The present invention realizes the above idea, and employs the following configuration as means for reducing the amount of gas at the initial stage of generation and continuing this small amount of generated gas in a stable state for a long time.

  That is, the present invention is to divert the flame generated by the ignition of the ignition agent inserted in the tube above the upper end of the tube, and to guide the gas generating agent from above to burn the gas generating agent. For example, the tube 4 was changed as follows, and the inner lid 10 was added.

  That is, in the present invention, unlike the conventional tube 4 shown in FIG. 2 (b), a tube 4 that does not have a flame releasing slit 4a on the side wall is adopted as shown in FIG. 2 (a). Further, in order to provide a gap serving as a bypass for the flame between the housing 2 and the housing 2, as shown in FIG.

  In order to guide the flame of the ignition powder 5 arranged in the tube 4 to the gap, the inner lid 10 is provided with a through-hole 10b as shown in FIG. The inner lid 10 is also provided with a through hole 10 a at a position communicating with the outer peripheral side of the tube 4.

  If such a tube 4 not provided with a slit 4a for releasing flame is used on the side wall, the ignition agent 5 ignited in the cup 6 by the ignition of the initiator 3 (a in FIG. 1) (from (b) in FIG. ) Rises in the tube 4.

  The flame that has risen in the tube 4 is once discharged into a gap outside the tube 4 from the through hole 10 b provided in the inner lid 10. The flame released into the gap outside the tube 4 strikes the diffuser 2a and reverses (d "in FIG. 1), burns the gas generating agent 7 from above through the through-hole 10a (d) in FIG. Generated (f in FIG. 1).

  In the case of the above ignition path, the gas generating agent 7 is burned in the vertical direction from the upper side to the lower side of the gas generating agent 7 as compared with the conventional case where the gas generating agent 7 burns in the radial direction from the vicinity of the ignition portion toward the outer peripheral side. Accordingly, the combustion surface area per unit time is small and constant, and a small amount of generated gas continues stably for a long time.

  In the case of such gas generation, the amount of gas per unit time in the initial stage of gas generation is reduced, but gas is generated while maintaining a stable state for a long time, and a sudden rise in output is suppressed. can do. Therefore, the components of the airbag module can be simplified and the cost can be reduced.

  Incidentally, the prediction diagram of the gas generation amount of the invention shown in FIG. 1 and the conventional product shown in FIG. 5 is shown in FIG. 4. From FIG. 4, in the case of the present invention, the sudden rise of the output is suppressed. I understand that I can do it.

  The present invention is not limited to the above examples, and the embodiments may be appropriately changed as long as they are included in the scope of the technical idea described in each claim.

  That is, the airbag inflator described above is a preferred example of the present invention, and other embodiments can be implemented or performed by various methods. In particular, the present invention is not limited to the detailed shape, size, configuration, and the like of the components shown in the accompanying drawings unless otherwise specified in the present specification. In addition, expressions and terms used in the present specification are for the purpose of explanation, and are not limited thereto unless specifically limited.

  For example, in the example of the invention in FIG. 1, an example in which the ignition powder 5 is stored in the cup 6 is shown, but the cup 6 is not necessarily required.

  The present invention described above can be applied not only to a single stage type but also to a double stage type inflator.

DESCRIPTION OF SYMBOLS 1 Inflator 2 Housing 2a Diffuser 2b Adapter 2c Base 3 Initiator 4 Tube 5 Igniter 7 Gas generating agent 10 Inner lid 10b Through-hole

Claims (2)

Inside the housing,
at least,
An initiator ,
An ignition agent that is ignited by ignition of the initiator,
A gas generating agent that is ignited and burned by the ignition of the ignition powder;
A tube for partitioning the gas generating agent and the initiator and the ignition agent ;
A filter disposed on the inner peripheral side of the side wall of the housing in order to form a housing for the gas generating agent with this tube;
An inner lid that covers this filter and the tube is disposed,
A through-hole that allows a gap to be formed between the inner cover and the housing that covers the filter and the tube, and that discharges a flame generated by ignition of the ignition agent into the gap. And a through hole is provided at a position communicating with the outer peripheral side of the tube, and the flame generated by the ignition of the ignition powder is bypassed above the upper end of the tube, and is guided from above the gas generating agent. An air bag inflator characterized in that the gas generating agent is combusted from above, and the generated gas is jetted out of the housing through the filter . The airbag inflator according to claim 1, wherein the tube is not provided with a slit for releasing a flame on a side wall .

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