Squib

Abstract

A squib includes a heat-generating portion that has an energizing portion and a fuel portion, and that is formed such that heat that is generated by supplying current to the energizing portion can be transmitted to the fuel portion to ignite same. The squib includes a noise removal device that is connected in parallel with the heat generating portion, and a circuit element that temporally scatters noise such that the noise is more completely removed by the noise removal device. In this manner, the heat-generating portion is protected from all typed of noise, including momentary noise, increasing reliability of the squib.

Description

[0001] Priority is claimed on Japanese Patent Application No. 2003-419478, filed Dec. 17, 2003, the contents of which are incorporated herein by reference. BACKGROUND OF THE INVENTION [0002] The present invention relates to a squib (i.e., an ignition apparatus) that is used in an explosive-actuated system for driving, for example, a seat belt pretensioner apparatus or an airbag apparatus for an automobile, and, in particular, to a squib that is provided with a heat generating portion capable of generating heat by means of a small amount of energy. [0003] In recent years squibs are used with the aim of igniting a gas generating agent in order to operate systems inclusive of, for instance, a seat belt pretensioner apparatus and an airbag apparatus. Generally, the squib is attached to an inflator that contains a gas generating agent in an explosive-actuated system. The squib is structured such that a heat generating portion is attached to a header to which pins are fixed, and an explos...

AI Technical Summary

Benefits of technology

[0009] According to the present invention, even when the noise is generated due to, for example, static electricity that is generated by the momentary supply of a large amount of power, it is possible to scatter the noise over a sufficient time period by means of the circuit element. As a result, the momentary noise thus scattered can be removed by the noise removal device. Accordingly, the heat generating portion can be protected from the noise even if the momentary noise is applied thereto, and reliability can thereby be increased.

[0011] According to this aspect, the two-way zener diode can be operated irrespective of the direction of the noise that is applied to the two-way zener diode. As a result, the reliability can be further improved.

[0013] According to this aspect, when the noise is being scattered temporally, the influence of the scattering on the ignition current can be reduced to a minimum. As a result, the heat generating portion can be protected from noise without losing the characteristics of the low energy squib that achieves an ignition using a small amount of energy being impaired.

[0014] In consequence, the first aspect of the present invention enables the heat generating portion to be protected from noise even if the momentary noise is applied thereto, and enables reliability to thereby be increased.

[0015] The second aspect of the present invention enables the two-way zener diode to be operated irrespective of the direction of the noise, thereby enabling the reliability to be further improved.

[0016] The third aspect of the present invention enables the influence of the scattering on the ignition current to be practically reduced to a minimum when the noise is being scattered temporally, thereby enabling the heat generating portion to be protected from noise without deteriorating the characteristics of the low energy squib that achieves an ignition using a small amount of energy being impaired.

Problems solved by technology

When current is supplied to the energizing portion, it causes a violent chemical reaction and a large quantity of heat is generated.

However, if the zener diode is simply connected to the heat generating portion of the low energy squib, a certain period of time, i.e., a delay time is needed until the zener diode operates against the applied noise.

Therefore, the zener diode does not operate effectively against momentary noise such as static electricity and, therefore, there is a possibility that the noise will intrude into the heat generating portion.

This creates the problem that there is a possibility that the reliability thereof will deteriorate.

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